Facebook users flipping through their feeds in the fall of 2016 faced a minefield of targeted advertisements pitting blacks against police, southern whites against immigrants, gun owners against Obama supporters and the LGBTQ community against the conservative right.
Placed by distant Russian trolls, they didn't aim to prop up one candidate or cause, but to turn Americans against one another.
The ads were cheaply made and full of threatening, vulgar language.
And, according to a sweeping new analysis of more than 2,500 of the ads, they were remarkably effective, eliciting clickthrough rates as much as nine times higher than what is typical in digital advertising.
"We found that fear and anger appeals work really well in getting people to engage," said lead author Chris Vargo, an assistant professor of Advertising, Public Relations and Media Design at University of Colorado Boulder.
The study, published this week in Journalism and Mass Communication Quarterly, is the first to take a comprehensive look at ads placed by the infamous Russian propaganda machine known as the Internet Research Agency (IRA) and ask: How effective were they? And what makes people click on them?
While focused on ads running in 2016, the study's findings resonate in the age of COVID-19 and the run-up to the 2020 election, the authors say.
"As consumers continue to see ads that contain false claims and are intentionally designed to use their emotions to manipulate them, it's important for them to have cool heads and understand the motives behind them," said Vargo.
For the study, Vargo and assistant professor of advertising Toby Hopp scoured 2,517 Facebook and Instagram ads downloaded from the U.S. House of Representatives Permanent Select Committee On Intelligence website. The committee made the ads publicly available in 2018 after concluding that the IRA had been creating fake U.S. personas, setting up fake social media pages, and using targeted paid advertising to "sow discord" among U.S. residents.
Using computational tools and manual coding, Vargo and Hopp analyzed every ad, looking for the inflammatory, obscene or threatening words and language hostile to a particular group's ethnic, religious or sexual identity. They also looked at which groups each ad targeted, how many clicks the ad got, and how much the IRA paid.
Collectively, the IRA spent about $75,000 to generate about 40.5 million impressions with about 3.7 million users clicking on them -- a clickthrough rate of 9.2%.
That compares to between .9% and 1.8% for a typical digital ad.
While ads using blatantly racist language didn't do well, those using cuss words and inflammatory words (like "sissy," "idiot," "psychopath" and "terrorist") or posing a potential threat did. Ads that evoked fear and anger did the best.
One IRA advertisement targeting users with an interest in the Black Lives Matter movement stated: "They killed an unarmed guy again! We MUST make the cops stop thinking that they are above the law!" Another shouted: "White supremacists are planning to raise the racist flag again!" Meanwhile, ads targeting people who sympathized with white conservative groups read "Take care of our vets; not illegals" or joked "If you voted for Obama: We don't want your business because you are too stupid to own a firearm."
Only 110 out of 2,000 mentioned Donald Trump.
"This wasn't about electing one candidate or another," said Vargo. "It was essentially a make-Americans-hate-each-other campaign."
The ads were often unsophisticated, with spelling or grammatical errors and poorly photoshopped images. Yet at only a few cents to distribute, the IRA got an impressive rate of return.
"I was shocked at how effective these appeals were," said Vargo.
The authors warn that they have no doubt such troll farms are still at it.
According to some news reports, Russian trolls are already engaged in disinformation campaigns around COVID-19.
"I think with any major story, you are going to see this kind of disinformation circulated," said Hopp. "There are bad actors out there who have goals that are counter to the aspirational goals of American democracy, and there are plenty of opportunities for them to take advantage of the current structure of social media."
Ultimately, the authors believe better monitoring, via both machine algorithms and human reviewers, could help stem the tide of disinformation.
Read more at Science Daily
Mar 28, 2020
Worldwide scientific collaboration unveils genetic architecture of gray matter
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| Brain and DNA concept illustration |
Now, for the first time, more 360 scientists from 184 different institutions -- including UNC-Chapel Hill -- have contributed to a global effort to find more than 200 regions of the genome and more than 300 specific genetic variations that affect the structure of the cerebral cortex and likely play important roles in psychiatric and neurological conditions.
The study, published in Science, was led by co-senior authors Jason Stein, PhD, assistant professor in the Department of Genetics at the UNC School of Medicine; Sarah Medland, PhD, senior research fellow at the QIMR Berghofer Medical Research Institute in Australia; and Paul Thompson, PhD, associate director of the Mark and Mary Stevens Neuroimaging and Informatics Institute at the University of Southern California. Ten years ago, these scientists cofounded the ENIGMA Consortium, an international research network that has brought together hundreds of imaging genomics researchers to understand brain structure, function, and disease based on brain imaging and genetic data.
"This study was only possible due to a huge scientific collaboration of more than 60 sites involved in MRI scanning and genotyping participants," Stein said. "This study is the crown jewel of the ENIGMA Consortium, so far."
The researchers studied MRI scans and DNA from more than 50,000 people to identify 306 genetic variants that influence brain structure in order to shed light on how genetics contribute to differences in the cerebral cortex of individuals. Genetic variants or variations are simply the slight genetic differences that make us unique. Generally speaking, some variants contribute to differences such as hair color or blood type. Some are involved in diseases. Most of the millions of genetic variants, though, have no known significance. This is why pinpointing genetic variants associated with cortex size and structure is a big deal. Stein and colleagues consider their new genetic roadmap of the brain a sort of "Rosetta stone" that will help translate how some genes impact physical brain structure and neurological consequences for individuals.
Among the findings of the research published in Science:
- Some genetic variants are associated with cortical folding, measured as surface area, while other genetic variants are associated with the thickness of the cortex.
- Genes that determine surface area are related to very early development in the fetal cortex, while thickness appears to be driven by genes active in the adult cortex.
- People at genetic risk for depression or insomnia are genetically inclined toward having lower surface area, while people with a genetic risk for Parkinson's disease tend to have higher surface area.
- The vast scale of the project allowed the discovery of specific genes that drive brain development and aging in people worldwide.
"Most of our previous understanding of genes affecting the brain are from model systems, like mice," Stein said. "With mice, we can find genes, knock out genes, or over express genes to see how they influence the structure or function of the brain. But there are a couple of problems with this."
One problem is, quite simply, a mouse is not a human. There are many human-specific features that scientists can only study in the human brain.
"The genetic basis for a mouse is very different than the genetic basis for humans," Stein said, "especially in in the noncoding regions of the genome."
Genes contain DNA, the basic human code that, when translated into action, creates proteins that "do" things, such as help your finger muscles type or your heart beat or your liver process toxins. But only about 3 percent of the human genome codes for proteins. The vast majority of the human genome is called the noncoding genome. Much of this region is not shared between mice and humans. This noncoding genome consists of tiny molecular switches that can modulate the expression of other genes. These switches don't directly alter the function of a protein, but they can affect the amounts of a protein that is expressed. Turns out, most genetic variants associated with psychiatric disorders are found in the noncoding region of the genome.
These findings can now be a resource for scientists to help answer important questions about the genetic influences on the brain and how they relate to numerous conditions.
Aysenil Berger, PhD, director of Psychiatry Neuroimaging Research and director of the Frank Porter Graham Child Development Institute at UNC-Chapel Hill, is a co-author on the study.
Read more at Science Daily
Mar 27, 2020
Neanderthals ate mussels, fish, and seals too
Over 80,000 years ago, Neanderthals were already feeding themselves regularly on mussels, fish and other marine life. The first robust evidence of this has been found by an international research team with the participation of the University of Göttingen during an excavation in the cave of Figueira Brava in Portugal. Dr Dirk Hoffmann at the Göttingen Isotope Geology Department dated flowstone layers -- calcite deposits that form like stalagmites from dripping water -- using the uranium-thorium method, and was thus able to determine the age of the excavation layers to between 86,000 and 106,000 years. This means that the layers date from the period in which the Neanderthals settled in Europe. The use of the sea as a source of food at that time has so far only been attributed to anatomically modern humans (Homo sapiens) in Africa. The results of the study were published in the journal Science.
The cave of Figueira Brava is located 30 kilometres south of Lisbon on the slopes of the Serra da Arrábida. Today it is located directly on the waterfront, but at that time it was up to two kilometres from the coast. The research team, coordinated by the first author of the study, Professor João Zilhão from the University of Barcelona, found that the Neanderthals living there were able to routinely harvest mussels and fish, and to hunt seals. Their diet included mussels, crustaceans and fish as well as waterfowl and marine mammals such as dolphins and seals. Food from the sea is rich in omega-3 fatty acids and other fatty acids that promote the development of brain tissue.
Until now, it has always been suspected that this consumption increased the cognitive abilities of the human populations in Africa. "Among other influences, this could explain the early appearance of a culture of modern people that used symbolic artefacts, such as body painting with ochre, the use of ornaments or the decoration of containers made of ostrich eggs with geometric motifs," explains Hoffmann. "Such behaviour reflects human's capacity for abstract thought and communication through symbols, which also contributed to the emergence of more organised and complex societies of modern humans."
The recent results of the excavation of Figueira Brava now confirm that if the habitual consumption of marine life played an important role in the development of cognitive abilities, this is as true for Neanderthals as it is for anatomically modern humans. Hoffmann and his co-authors previously found that Neanderthals made cave paintings in three caves on the Iberian Peninsula more than 65,000 years ago and that perforated and painted shells must also be attributed to the Neanderthals.
Read more at Science Daily
The cave of Figueira Brava is located 30 kilometres south of Lisbon on the slopes of the Serra da Arrábida. Today it is located directly on the waterfront, but at that time it was up to two kilometres from the coast. The research team, coordinated by the first author of the study, Professor João Zilhão from the University of Barcelona, found that the Neanderthals living there were able to routinely harvest mussels and fish, and to hunt seals. Their diet included mussels, crustaceans and fish as well as waterfowl and marine mammals such as dolphins and seals. Food from the sea is rich in omega-3 fatty acids and other fatty acids that promote the development of brain tissue.
Until now, it has always been suspected that this consumption increased the cognitive abilities of the human populations in Africa. "Among other influences, this could explain the early appearance of a culture of modern people that used symbolic artefacts, such as body painting with ochre, the use of ornaments or the decoration of containers made of ostrich eggs with geometric motifs," explains Hoffmann. "Such behaviour reflects human's capacity for abstract thought and communication through symbols, which also contributed to the emergence of more organised and complex societies of modern humans."
The recent results of the excavation of Figueira Brava now confirm that if the habitual consumption of marine life played an important role in the development of cognitive abilities, this is as true for Neanderthals as it is for anatomically modern humans. Hoffmann and his co-authors previously found that Neanderthals made cave paintings in three caves on the Iberian Peninsula more than 65,000 years ago and that perforated and painted shells must also be attributed to the Neanderthals.
Read more at Science Daily
ALMA resolves gas impacted by young jets from supermassive black hole
Astronomers obtained the first resolved image of disturbed gaseous clouds in a galaxy 11 billion light-years away by using the Atacama Large Millimeter/submillimeter Array (ALMA). The team found that the disruption is caused by young powerful jets ejected from a supermassive black hole residing at the center of the host galaxy. This result will cast light on the mystery of the evolutionary process of galaxies in the early Universe.
It is commonly known that black holes exert strong gravitational attraction on surrounding matter. However, it is less well known that some black holes have fast-moving streams of ionized matter, called jets. In some nearby galaxies, evolved jets blow off galactic gaseous clouds, resulting in suppressed star formation. Therefore, to understand the evolution of galaxies, it is crucial to observe the interaction between black hole jets and gaseous clouds throughout cosmic history. However, it had been difficult to obtain clear evidence of such interaction, especially in the early Universe.
In order to obtain such clear evidence, the team used ALMA to observe an interesting object known as MG J0414+0534. A distinctive feature of MG J0414+0534 is that the paths of light traveling from it to Earth are significantly distorted by the gravity of another 'lensing' galaxy between MG J0414+0534 and us, causing significant magnification.
"This distortion works as a 'natural telescope' to enable a detailed view of distant objects," says Takeo Minezaki, an associate professor at the University of Tokyo.
Another feature is that MG J0414+0534 has a supermassive black hole with bipolar jets at the center of the host galaxy. The team was able to reconstruct the 'true' image of gaseous clouds as well as the jets in MG J0414+0534 by carefully accounting for the gravitational effects exerted by the intervening lensing galaxy.
"Combining this cosmic telescope and ALMA's high-resolution observations, we obtained exceptionally sharp vision, that is 9,000 times better than human eyesight," adds Kouichiro Nakanishi, a project associate professor at the National Astronomical Observatory of Japan/SOKENDAI. "With this extremely high resolution, we were able to obtain the distribution and motion of gaseous clouds around jets ejected from a supermassive black hole."
Thanks to such a superior resolution, the team found that gaseous clouds along the jets have violent motion with speeds as high as 600 km/s, showing clear evidence of impacted gas. Moreover, it turned out that the size of the impacted gaseous clouds and the jets are much smaller than the typical size of a galaxy at this age.
"We are perhaps witnessing the very early phase of jet evolution in the galaxy," says Satoki Matsushita, a research fellow at Academia Sinica Institute of Astronomy and Astrophysics. "It could be as early as several tens of thousands of years after the launch of the jets."
Read more at Science Daily
It is commonly known that black holes exert strong gravitational attraction on surrounding matter. However, it is less well known that some black holes have fast-moving streams of ionized matter, called jets. In some nearby galaxies, evolved jets blow off galactic gaseous clouds, resulting in suppressed star formation. Therefore, to understand the evolution of galaxies, it is crucial to observe the interaction between black hole jets and gaseous clouds throughout cosmic history. However, it had been difficult to obtain clear evidence of such interaction, especially in the early Universe.
In order to obtain such clear evidence, the team used ALMA to observe an interesting object known as MG J0414+0534. A distinctive feature of MG J0414+0534 is that the paths of light traveling from it to Earth are significantly distorted by the gravity of another 'lensing' galaxy between MG J0414+0534 and us, causing significant magnification.
"This distortion works as a 'natural telescope' to enable a detailed view of distant objects," says Takeo Minezaki, an associate professor at the University of Tokyo.
Another feature is that MG J0414+0534 has a supermassive black hole with bipolar jets at the center of the host galaxy. The team was able to reconstruct the 'true' image of gaseous clouds as well as the jets in MG J0414+0534 by carefully accounting for the gravitational effects exerted by the intervening lensing galaxy.
"Combining this cosmic telescope and ALMA's high-resolution observations, we obtained exceptionally sharp vision, that is 9,000 times better than human eyesight," adds Kouichiro Nakanishi, a project associate professor at the National Astronomical Observatory of Japan/SOKENDAI. "With this extremely high resolution, we were able to obtain the distribution and motion of gaseous clouds around jets ejected from a supermassive black hole."
Thanks to such a superior resolution, the team found that gaseous clouds along the jets have violent motion with speeds as high as 600 km/s, showing clear evidence of impacted gas. Moreover, it turned out that the size of the impacted gaseous clouds and the jets are much smaller than the typical size of a galaxy at this age.
"We are perhaps witnessing the very early phase of jet evolution in the galaxy," says Satoki Matsushita, a research fellow at Academia Sinica Institute of Astronomy and Astrophysics. "It could be as early as several tens of thousands of years after the launch of the jets."
Read more at Science Daily
Forgotten tale of phage therapy history revealed
In the current situation when the fear of virus infections in the public is common, it is good to remember that some viruses can be extremely beneficial for humankind, even save lives. Such viruses, phages, infect bacteria. The research conducted at the University of Jyväskylä shed some light on the phage therapy history. It revealed that Brazil was a strong user and developer of phage therapy in 1920-40's. The research was published in Lancet Infectious Diseases -publication on March 2020.
After decades of antibiotic use and misuse, natural selection is giving bacteria the upper hand. The World Health Organization (WHO) warned that we are reaching the post-antibiotic era. As more pathogens become resistant, our chances to find new antibiotics diminish. Therefore, alternatives are urgently needed.
Use of phages, viruses that kill bacteria, as therapeutics was developed in Paris around 1920. Since these viruses could be safely used to treat patients, phage therapy quickly spread, but then slowly disappeared from the western world decades later, as antibiotics became common. Now, the revival of phage therapy is considered one viable solution to the antimicrobial resistance crisis.
Researchers of the University of Jyvaskyla investigated a forgotten hotspot of phage therapy of the past. Historical medical records in Portuguese (1915-1952) revealed that Brazil was a strong user and developer of phage therapy. From pioneer mass testing of phage products to routine, details have been uncovered about the safe use of phages against dysentery and staphylococcal infections. This information was made available to the modern research community by a historical review publication.
The practical and clinical data revealed can be important to shape modern phage therapy, against acute dysenteric infections and against dangerous resistant pathogens such as MRSA.
"The literature researched was an interesting trip to the past. This work is in principle a historical review, but it also provides relevant information to modern researchers. It might be an incentive to similar investigations on other countries, besides being a spark of hope to the recent Brazilian research community," says Postdoctoral Researcher Gabriel Almeida from the University of Jyväskylä.
From Science Daily
After decades of antibiotic use and misuse, natural selection is giving bacteria the upper hand. The World Health Organization (WHO) warned that we are reaching the post-antibiotic era. As more pathogens become resistant, our chances to find new antibiotics diminish. Therefore, alternatives are urgently needed.
Use of phages, viruses that kill bacteria, as therapeutics was developed in Paris around 1920. Since these viruses could be safely used to treat patients, phage therapy quickly spread, but then slowly disappeared from the western world decades later, as antibiotics became common. Now, the revival of phage therapy is considered one viable solution to the antimicrobial resistance crisis.
Researchers of the University of Jyvaskyla investigated a forgotten hotspot of phage therapy of the past. Historical medical records in Portuguese (1915-1952) revealed that Brazil was a strong user and developer of phage therapy. From pioneer mass testing of phage products to routine, details have been uncovered about the safe use of phages against dysentery and staphylococcal infections. This information was made available to the modern research community by a historical review publication.
The practical and clinical data revealed can be important to shape modern phage therapy, against acute dysenteric infections and against dangerous resistant pathogens such as MRSA.
"The literature researched was an interesting trip to the past. This work is in principle a historical review, but it also provides relevant information to modern researchers. It might be an incentive to similar investigations on other countries, besides being a spark of hope to the recent Brazilian research community," says Postdoctoral Researcher Gabriel Almeida from the University of Jyväskylä.
From Science Daily
How cognitive intelligence is a whole brain phenomenon
An international collaborative study led by researchers from the NUI Galway provides findings on the neural basis of intelligence, otherwise known as general cognitive ability (IQ).
This new research uses an imaging technique called diffusion tensor imaging (DTI) to provide an insight into how small variations in this wiring system is associated with differences in IQ in both the general population and how disorders such as schizophrenia manifest.
Over 40 scientists from around the world were involved in analysing brain MRI scans and measures of cognitive function of 1,717 participants, with both healthy functions and patients with schizophrenia. This resulted in a new method to harmonise data collection and analysis as part of the Enhancing Neuroimaging Genetics through Meta-Analysis project (ENIGMA), Schizophrenia Working Group. The study, published in The American Journal of Psychiatry, was led by Dr Laurena Holleran, Lecturer in Clinical Neuroscience and Professor Gary Donohoe, Established Professor at NUI Galway's School of Psychology and Centre for Neuroimaging Cognition and Genomics.
Commenting on the findings, lead author Dr Laurena Holleran, stated that: "To date, this is the largest meta-analysis study of brain structure and cognitive function in schizophrenia. Understanding the neural basis of cognitive function is essential so that effective therapies that address difficulties associated with disorders like schizophrenia, which aren't targeted by current treatments. This is important because cognitive deficits associated with the disorder strongly predict social and functional outcomes, such as employment or social relationships.
"Previous literature suggested that general intelligence relies on specific grey matter areas of the brain, including temporal, parietal and frontal regions. However, the results from this study indicate that efficient connection pathways across the entire brain provide a neural network that supports general cognitive function."
According to the study's senior author Professor Gary Donohoe: "These results advance our knowledge in a number of ways. Firstly, we have demonstrated that the relationship between brain structure and intelligence not only involves grey matter, but also white matter -- the brain's wiring system. Secondly, it's not just one part of this wiring system that is important for intelligence, but rather the wiring system as a whole. And finally, the relationship between intelligence and the brain's wiring system is basically the same in patients with schizophrenia and healthy people, in that the lack of pattern explains their cognitive abilities. This suggests that cognitive function in patients is the same as the general population, at least as far as white matter is concerned."
From Science Daily
This new research uses an imaging technique called diffusion tensor imaging (DTI) to provide an insight into how small variations in this wiring system is associated with differences in IQ in both the general population and how disorders such as schizophrenia manifest.
Over 40 scientists from around the world were involved in analysing brain MRI scans and measures of cognitive function of 1,717 participants, with both healthy functions and patients with schizophrenia. This resulted in a new method to harmonise data collection and analysis as part of the Enhancing Neuroimaging Genetics through Meta-Analysis project (ENIGMA), Schizophrenia Working Group. The study, published in The American Journal of Psychiatry, was led by Dr Laurena Holleran, Lecturer in Clinical Neuroscience and Professor Gary Donohoe, Established Professor at NUI Galway's School of Psychology and Centre for Neuroimaging Cognition and Genomics.
Commenting on the findings, lead author Dr Laurena Holleran, stated that: "To date, this is the largest meta-analysis study of brain structure and cognitive function in schizophrenia. Understanding the neural basis of cognitive function is essential so that effective therapies that address difficulties associated with disorders like schizophrenia, which aren't targeted by current treatments. This is important because cognitive deficits associated with the disorder strongly predict social and functional outcomes, such as employment or social relationships.
"Previous literature suggested that general intelligence relies on specific grey matter areas of the brain, including temporal, parietal and frontal regions. However, the results from this study indicate that efficient connection pathways across the entire brain provide a neural network that supports general cognitive function."
According to the study's senior author Professor Gary Donohoe: "These results advance our knowledge in a number of ways. Firstly, we have demonstrated that the relationship between brain structure and intelligence not only involves grey matter, but also white matter -- the brain's wiring system. Secondly, it's not just one part of this wiring system that is important for intelligence, but rather the wiring system as a whole. And finally, the relationship between intelligence and the brain's wiring system is basically the same in patients with schizophrenia and healthy people, in that the lack of pattern explains their cognitive abilities. This suggests that cognitive function in patients is the same as the general population, at least as far as white matter is concerned."
From Science Daily
Mar 26, 2020
Pablo Escobar's hippos may help counteract a legacy of extinctions
When cocaine kingpin Pablo Escobar was shot dead in 1993, the four hippos he brought to his private zoo in Colombia were left behind in a pond on his ranch. Since then, their numbers have grown to an estimated 80-100, and the giant herbivores have made their way into the country's rivers. Scientists and the public alike have viewed Escobar's hippos as invasive pests that by no rights should run wild on the South American continent.
A new study published in Proceedings of the National Academy of Sciences by an international group of researchers challenges this view. Through a worldwide analysis comparing the ecological traits of introduced herbivores like Escobar's hippos to those of the past, they reveal that such introductions restore many important traits that have been lost for thousands of years. While human impacts have caused the extinction of several large mammals over the last 100,000 years, humans have since introduced numerous species, inadvertently rewilding many parts of the world such as South America, where giant llamas once roamed, and North America, where the flat-headed peccary could once be found from New York to California.
"While we found that some introduced herbivores are perfect ecological matches for extinct ones, in others cases the introduced species represents a mix of traits seen in extinct species," says study co-author John Rowan, Darwin Fellow in organismic and evolutionary biology at the University of Massachusetts Amherst. "For example, the feral hippos in South America are similar in diet and body size to extinct giant llamas, while a bizarre type of extinct mammal -- a notoungulate -- shares with hippos large size and semiaquatic habitats. So, while hippos don't perfectly replace any one extinct species, they restore parts of important ecologies across several species."
Rowan was part of an international team of conservation biologists and ecologists from The University of Technology Sydney (UTS) in Australia, the University of Kansas and the University of California Davis and the Natural History Museum of Los Angeles County in the U.S., the University of Sussex in the U.K., the Universidad de Alcalá in Spain and Aarhus University in Denmark.
The authors note that what most conservation biologists and ecologists think of as the modern 'natural' world is very different than it was for the last 45 million years. Even recently, rhino-sized wombat-relatives called diprotodons, tank-like armored glyptodons and two-story tall sloths ruled the world. These giant herbivores began their evolutionary rise not long after the demise of the dinosaurs, but were abruptly driven extinct beginning around 100,000 years ago, most likely due to hunting and other pressures from our Late Pleistocene ancestors.
The researchers found that by introducing species across the world, humans restored lost ecological traits to many ecosystems; making the world more similar to the pre-extinction Late Pleistocene and counteracting a legacy of extinctions.
Erick Lundgren, lead author and Ph.D. student at the UTS Centre for Compassionate Conservation (CfCC), says the possibility that introduced herbivores might restore lost ecological functions had been suggested but not "rigorously evaluated."
To this end, the authors compared key ecological traits of herbivore species from before the Late Pleistocene extinctions to the present day, such as body size, diet and habitat.
"This allowed us to compare species that are not necessarily closely related to each other, but are similar in terms of how they affect ecosystems," Lundgren said. "By doing this, we could quantify the extent to which introduced species make the world more similar or dissimilar to the pre-extinction past. Amazingly they make the world more similar."
This is largely because 64% of introduced herbivores are more similar to extinct species than to local native species. These introduced 'surrogates' for extinct species include evolutionary close species in some places, like mustangs (wild horses) in North America, where pre-domestic horses of the same species lived but were driven extinct.
"Many people are concerned about feral horses and donkeys in the American southwest, because they aren't known from the continent in historic times," Rowan says. "But this view overlooks the fact that horses had been present in North America for over 50 million years -- all major milestones of their evolution, including their origin, takes place here. They only disappeared a few thousand years ago because of humans, meaning the North American ecosystems they have since been reintroduced to had coevolved with horses for millions of years."
"We usually think of nature as defined by the short period of time for which we have recorded history but this is already long after strong and pervasive human influences," said senior author Arian Wallach from UTS CfCC. "Broadening our perspective to include the more evolutionarily relevant past lets us ask more nuanced questions about introduced species and how they affect the world."
Read more at Science Daily
A new study published in Proceedings of the National Academy of Sciences by an international group of researchers challenges this view. Through a worldwide analysis comparing the ecological traits of introduced herbivores like Escobar's hippos to those of the past, they reveal that such introductions restore many important traits that have been lost for thousands of years. While human impacts have caused the extinction of several large mammals over the last 100,000 years, humans have since introduced numerous species, inadvertently rewilding many parts of the world such as South America, where giant llamas once roamed, and North America, where the flat-headed peccary could once be found from New York to California.
"While we found that some introduced herbivores are perfect ecological matches for extinct ones, in others cases the introduced species represents a mix of traits seen in extinct species," says study co-author John Rowan, Darwin Fellow in organismic and evolutionary biology at the University of Massachusetts Amherst. "For example, the feral hippos in South America are similar in diet and body size to extinct giant llamas, while a bizarre type of extinct mammal -- a notoungulate -- shares with hippos large size and semiaquatic habitats. So, while hippos don't perfectly replace any one extinct species, they restore parts of important ecologies across several species."
Rowan was part of an international team of conservation biologists and ecologists from The University of Technology Sydney (UTS) in Australia, the University of Kansas and the University of California Davis and the Natural History Museum of Los Angeles County in the U.S., the University of Sussex in the U.K., the Universidad de Alcalá in Spain and Aarhus University in Denmark.
The authors note that what most conservation biologists and ecologists think of as the modern 'natural' world is very different than it was for the last 45 million years. Even recently, rhino-sized wombat-relatives called diprotodons, tank-like armored glyptodons and two-story tall sloths ruled the world. These giant herbivores began their evolutionary rise not long after the demise of the dinosaurs, but were abruptly driven extinct beginning around 100,000 years ago, most likely due to hunting and other pressures from our Late Pleistocene ancestors.
The researchers found that by introducing species across the world, humans restored lost ecological traits to many ecosystems; making the world more similar to the pre-extinction Late Pleistocene and counteracting a legacy of extinctions.
Erick Lundgren, lead author and Ph.D. student at the UTS Centre for Compassionate Conservation (CfCC), says the possibility that introduced herbivores might restore lost ecological functions had been suggested but not "rigorously evaluated."
To this end, the authors compared key ecological traits of herbivore species from before the Late Pleistocene extinctions to the present day, such as body size, diet and habitat.
"This allowed us to compare species that are not necessarily closely related to each other, but are similar in terms of how they affect ecosystems," Lundgren said. "By doing this, we could quantify the extent to which introduced species make the world more similar or dissimilar to the pre-extinction past. Amazingly they make the world more similar."
This is largely because 64% of introduced herbivores are more similar to extinct species than to local native species. These introduced 'surrogates' for extinct species include evolutionary close species in some places, like mustangs (wild horses) in North America, where pre-domestic horses of the same species lived but were driven extinct.
"Many people are concerned about feral horses and donkeys in the American southwest, because they aren't known from the continent in historic times," Rowan says. "But this view overlooks the fact that horses had been present in North America for over 50 million years -- all major milestones of their evolution, including their origin, takes place here. They only disappeared a few thousand years ago because of humans, meaning the North American ecosystems they have since been reintroduced to had coevolved with horses for millions of years."
"We usually think of nature as defined by the short period of time for which we have recorded history but this is already long after strong and pervasive human influences," said senior author Arian Wallach from UTS CfCC. "Broadening our perspective to include the more evolutionarily relevant past lets us ask more nuanced questions about introduced species and how they affect the world."
Read more at Science Daily
A possible treatment for COVID-19 and an approach for developing others
SARS-CoV-2, the virus that causes COVID-19 disease is more transmissible, but has a lower mortality rate than its sibling, SARS-CoV, according to a review article published this week in Antimicrobial Agents and Chemotherapy, a journal of the American Society for Microbiology.
In humans, coronaviruses cause mainly respiratory infections. Individuals with SARS-CoV-2 may remain asymptomatic for 2 to 14 days post-infection and some individuals likely transmit the virus without developing disease symptoms.
So far, the most promising compound for treating COVID-19 is the antiviral, remdesivir. It is currently in clinical trials for treating Ebola virus infections.
Remdesivir was recently tested in a non-human primate model of MERS-CoV infection. Prophylactic treatment 24 hours prior to inoculation prevented MERS-CoV from causing clinical disease and inhibited viral replication in lung tissues, preventing formation of lung lesions. Initiation of treatment 12 hours after virus inoculation was similarly effective.
Remdesivir has also shown effectiveness against a wide range of coronaviruses. It has already undergone safety testing in clinical trials for Ebola, thereby reducing the time that would be necessary for conducting clinical trials for SARS-CoV-2.
Nonetheless, much work needs to be done to gain a better understanding of the mechanics of SARS-CoV-2. For example, understanding how SARS-CoV-2 interacts with the host ACE2 receptor -- by which SARS-CoV-2 gains entry into the host (whether human or animal) -- might reveal how this virus overcame the species barrier between animals and humans. This could also lead to design of new antivirals.
Although coronaviruses are common in bats, no direct animal source of the epidemic has been identified to date, according to the report. "It is critical to identify the intermediate species to stop the current spread and to prevent future human SARS-related coronavirus epidemics," the researchers write.
From Science Daily
In humans, coronaviruses cause mainly respiratory infections. Individuals with SARS-CoV-2 may remain asymptomatic for 2 to 14 days post-infection and some individuals likely transmit the virus without developing disease symptoms.
So far, the most promising compound for treating COVID-19 is the antiviral, remdesivir. It is currently in clinical trials for treating Ebola virus infections.
Remdesivir was recently tested in a non-human primate model of MERS-CoV infection. Prophylactic treatment 24 hours prior to inoculation prevented MERS-CoV from causing clinical disease and inhibited viral replication in lung tissues, preventing formation of lung lesions. Initiation of treatment 12 hours after virus inoculation was similarly effective.
Remdesivir has also shown effectiveness against a wide range of coronaviruses. It has already undergone safety testing in clinical trials for Ebola, thereby reducing the time that would be necessary for conducting clinical trials for SARS-CoV-2.
Nonetheless, much work needs to be done to gain a better understanding of the mechanics of SARS-CoV-2. For example, understanding how SARS-CoV-2 interacts with the host ACE2 receptor -- by which SARS-CoV-2 gains entry into the host (whether human or animal) -- might reveal how this virus overcame the species barrier between animals and humans. This could also lead to design of new antivirals.
Although coronaviruses are common in bats, no direct animal source of the epidemic has been identified to date, according to the report. "It is critical to identify the intermediate species to stop the current spread and to prevent future human SARS-related coronavirus epidemics," the researchers write.
From Science Daily
New mathematical model can more effectively track epidemics
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| Global virus and disease spread concept |
A new model developed by Princeton and Carnegie Mellon researchers improves tracking of epidemics by accounting for mutations in diseases. Now, the researchers are working to apply their model to allow leaders to evaluate the effects of countermeasures to epidemics before they deploy them.
"We want to be able to consider interventions like quarantines, isolating people, etc., and then see how they affect an epidemic's spread when the pathogen is mutating as it spreads," said H. Vincent Poor, one of the researchers on this study and Princeton's interim dean of engineering.
The models currently used to track epidemics use data from doctors and health workers to make predictions about a disease's progression. Poor, the Michael Henry Strater University Professor of Electrical Engineering, said the model most widely used today is not designed to account for changes in the disease being tracked. This inability to account for changes in the disease can make it more difficult for leaders to counter a disease's spread. Knowing how a mutation could affect transmission or virulence could help leaders decide when to institute isolation orders or dispatch additional resources to an area.
"In reality, these are physical things, but in this model, they are abstracted into parameters that can help us more easily understand the effects of policies and of mutations," Poor said.
If the researchers can correctly account for measures to counter the spread of disease, they could give leaders critical insights into the best steps they could take in the face of pandemics. The researchers are building on work published March 17 in the Proceedings of the National Academy of Sciences. In that article, they describe how their model is able to track changes in epidemic spread caused by mutation of a disease organism. The researchers are now working to adapt the model to account for public health measures taken to stem an epidemic as well.
The researchers' work stems from their examination of the movement of information through social networks, which has remarkable similarities to the spread of biological infections. Notably, the spread of information is affected by slight changes in the information itself. If something becomes slightly more exciting to recipients, for example, they might be more likely to pass it along or to pass it along to a wider group of people. By modeling such variations, one can see how changes in the message change its target audience.
"The spread of a rumor or of information through a network is very similar to the spread of a virus through a population," Poor said. "Different pieces of information have different transmission rates. Our model allows us to consider changes to information as it spreads through the network and how those changes affect the spread."
"Our model is agnostic with regard to the physical network of connectivity among individuals," said Poor, an expert in the field of information theory whose work has helped establish modern cellphone networks. "The information is being abstracted into graphs of connected nodes; the nodes might be information sources or they might be potential sources of infection."
Obtaining accurate information is extremely difficult during an ongoing pandemic when circumstances shift daily, as we have seen with the COVID-19 virus. "It's like a wildfire. You can't always wait until you collect data to make decisions -- having a model can help fill this void," Poor said.
"Hopefully, this model could give leaders another tool to better understand the reasons why, for example, the COVID-19 virus is spreading so much more rapidly than predicted, and thereby help them deploy more effective and timely countermeasures," Poor said.
Read more at Science Daily
As the ocean warms, marine species relocate toward the poles
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| Greenland iceberg |
"The main surprise is how pervasive the effects were," says senior author Martin Genner, an evolutionary ecologist at the University of Bristol. "We found the same trend across all groups of marine life we looked at, from plankton to marine invertebrates, and from fish to seabirds."
The new study builds on earlier evidence for a prevailing effect of climate change on the distributions, abundance, and seasonality of marine species. Based on those findings, Genner's team reasoned that marine species should be doing well at the leading (poleward) edge of their ranges but poorly at their trailing (equatorward) side. They also realized that existing databases of global species distributions could be used to test this hypothesis.
Based on a thorough search of available data in the literature, the researchers now report on a global analysis of abundance trends for 304 widely distributed marine species over the last century. The results show that -- just as predicted -- abundance increases have been most prominent where sampling has taken place at the poleward side of species ranges, while abundance declines have been most prominent where sampling has taken place at the equatorward side of species ranges.
The findings show that large-scale changes in the abundance of species are well underway. They also suggest that marine species haven't managed to adapt to warmer conditions. The researchers therefore suggest that projected sea temperature increases of up to 1.5°C over pre-industrial levels by 2050 will continue to drive the latitudinal abundance shifts in marine species, including those of importance for coastal livelihoods.
"This matters because it means that climate change is not only leading to abundance changes, but intrinsically affecting the performance of species locally," Genner says. "We see species such as Emperor penguin becoming less abundant as water becomes too warm at their equatorward edge, and we see some fish such as European seabass thriving at their poleward edge where historically they were uncommon."
The findings show that climate change is affecting marine species in a highly consistent and non-trivial way. "While some marine life may benefit as the ocean warms, the findings point toward a future in which we will also see continued loss of marine life," Genner says.
The long-term data included in the study primarily represent the most well-studied regions of the world. The researchers say that more work is needed to understand how climate change has affected marine life in all regions of the world in greater detail.
Read more at Science Daily
Mar 25, 2020
Fossil finds give clues about flying reptiles in the Sahara 100 million years ago
Three new species of toothed pterosaurs -- flying reptiles of the Cretaceous period, some 100 million years ago -- have been identified in Africa by an international team of scientists led by Baylor University.
The pterosaurs, which soared above a world dominated by predators, formed part of an ancient river ecosystem in Africa that teemed with life including fish, crocodiles, turtles and several predatory dinosaurs.
"Pterosaur remains are very rare, with most known from Europe, South America and Asia. These new finds are very exciting and provide a window into the world of pterosaurs in Cretaceous Africa," said lead author Megan L. Jacobs, a doctoral candidate in geosciences at Baylor University.
The study, published in the journal Cretaceous Research, is helping to uncover the poorly known evolutionary history of Africa during the time of the dinosaurs. The research finds that African pterosaurs were quite similar to those found on other continents. Their world included crocodile-like hunters and carnivorous dinosaurs, with few herbivores. Many predators, including the toothed pterosaurs, preyed on a superabundance of fish.
"For such large animals, they would have weighed very little," Jacobs said. "Their wingspans were around 10 to 13 feet, with their bones almost paper-thin and full of air, very similar to birds. This allowed these awesome creatures to reach incredible sizes and still be able to take off and soar the skies."
Pterosaurs snatched up their prey while on the wing, using a set of large spike-like teeth to grab. Large pterosaurs such as these would have been able to forage over hundreds of miles, with fossil evidence showing they flew between South America and Africa, similar to present-day birds such as condors and albatrosses, researchers said.
The specimens -- identified by researchers from chunks of jaws with teeth -- were obtained from fossil miners in a small village called Beggaa, just outside Erfoud in southeast Morocco. These villagers daily climb halfway up the side of a large escarpment, known as the Kem Kem beds, to a layer of a coarse sand, the most fossiliferous bed.
"They excavate everything they find, from teeth to bones to almost complete skeletons," Jacobs said. "They then sell their finds to dealers and scientists who conduct fieldwork, ensuring the villagers make enough money to survive while we get new fossils to describe. These pterosaur fragments are unique and can be identified easily -- if you know what to look for."
One of the species, Anhanguera, previously was only known to be from Brazil. Another, Ornithocheirus, had until now only been found in England and Middle Asia.
This year's find brings to five the total of toothed pterosaurs whose remains have been found in the Kem Kem beds, with the first described in the 1990s and the second one last year, Jacobs said. The specimens will be part of an acquisition in a museum in Morocco.
From Science Daily
The pterosaurs, which soared above a world dominated by predators, formed part of an ancient river ecosystem in Africa that teemed with life including fish, crocodiles, turtles and several predatory dinosaurs.
"Pterosaur remains are very rare, with most known from Europe, South America and Asia. These new finds are very exciting and provide a window into the world of pterosaurs in Cretaceous Africa," said lead author Megan L. Jacobs, a doctoral candidate in geosciences at Baylor University.
The study, published in the journal Cretaceous Research, is helping to uncover the poorly known evolutionary history of Africa during the time of the dinosaurs. The research finds that African pterosaurs were quite similar to those found on other continents. Their world included crocodile-like hunters and carnivorous dinosaurs, with few herbivores. Many predators, including the toothed pterosaurs, preyed on a superabundance of fish.
"For such large animals, they would have weighed very little," Jacobs said. "Their wingspans were around 10 to 13 feet, with their bones almost paper-thin and full of air, very similar to birds. This allowed these awesome creatures to reach incredible sizes and still be able to take off and soar the skies."
Pterosaurs snatched up their prey while on the wing, using a set of large spike-like teeth to grab. Large pterosaurs such as these would have been able to forage over hundreds of miles, with fossil evidence showing they flew between South America and Africa, similar to present-day birds such as condors and albatrosses, researchers said.
The specimens -- identified by researchers from chunks of jaws with teeth -- were obtained from fossil miners in a small village called Beggaa, just outside Erfoud in southeast Morocco. These villagers daily climb halfway up the side of a large escarpment, known as the Kem Kem beds, to a layer of a coarse sand, the most fossiliferous bed.
"They excavate everything they find, from teeth to bones to almost complete skeletons," Jacobs said. "They then sell their finds to dealers and scientists who conduct fieldwork, ensuring the villagers make enough money to survive while we get new fossils to describe. These pterosaur fragments are unique and can be identified easily -- if you know what to look for."
One of the species, Anhanguera, previously was only known to be from Brazil. Another, Ornithocheirus, had until now only been found in England and Middle Asia.
This year's find brings to five the total of toothed pterosaurs whose remains have been found in the Kem Kem beds, with the first described in the 1990s and the second one last year, Jacobs said. The specimens will be part of an acquisition in a museum in Morocco.
From Science Daily
Brain or muscles, what do we lose first?
Someone dies somewhere in the world every 10 seconds owing to physical inactivity -- 3.2 million people a year according to the World Health Organisation (WHO). From the age of 50, there is a gradual decline not just in physical activity but also in cognitive abilities since the two are correlated. But which of them influences the other? Does physical activity impact on the brain or is it the other way around? To answer this question, researchers from the University of Geneva (UNIGE), Switzerland, and the NCCR Lives Swiss National Centre of Competence in Research used a database of over 100,000 people aged 50-90 whose physical and cognitive abilities were measured every two years for 12 years. The findings, which are published in the journal Health Psychology, show that -- contrary to what was previously thought -- cognitive abilities ward off inactivity much more than physical activity prevents the decline in cognitive abilities. All of which means we need to prioritise exercising our brains.
The literature in this area has been looking at the impact of physical activity on cognitive skills for a number of years. "Correlations have been established between these two factors, particularly in terms of memory, but also regarding the growth and survival of new neurons," begins Boris Cheval, a researcher at UNIGE's Swiss Centre for Affective Sciences (CISA). "But we have never yet formally tested which comes first: does physical activity prevent a decline in cognitive skills or vice versa? That's what we wanted to verify."
What came first: the chicken or the egg?
Earlier studies based on the correlation between physical activity and cognitive skills postulated that the former prevent the decline of the latter. "But what if this research only told half the story? That's what recent studies suggest, since they demonstrate that our brain is involved when it comes to engaging in physical activity," continues the Geneva-based researcher.
The UNIGE researchers tested the two possible options formally using data from the SHARE survey (Survey of Health, Aging and Retirement in Europe), a European-wide socio-economic database covering over 25 countries. "The cognitive abilities and level of physical activity of 105,206 adults aged 50 to 90 were tested every two years over a 12-year period," explains Matthieu Boisgontier, a researcher at the Lives Swiss National Centre of Competence in Research (NCCR Lives). Cognitive abilities were measured using a verbal fluency test (naming as many animals as possible in 60 seconds) and a memory test (memorising 10 words and reciting them afterwards). Physical activity was measured on a scale of 1 ("Never") to 4 ("More than once a week").
The Geneva researchers employed this data in three separate statistical models. In the first, they looked at whether physical activity predicted the change in cognitive skills over time; in the second, whether cognitive skills predicted the change in physical activity; and in the third, they tested the two possibilities bidirectionally. "Thanks to a statistical index, we found that the second model adjusted the most precisely to the data of the participants," says Cheval. The study demonstrates, therefore, that cognitive capacities mainly influence physical activity and not vice versa, as the literature to date had postulated. "Obviously, it's a virtuous cycle, since physical activity also influences our cognitive capacities. But, in light of these new findings, it does so to a lesser extent," points out Boisgontier.
Slowing down an inevitable decline
From the age of 50, the decline in physical and cognitive abilities is inevitable. However, these results indicate that, contrary to what was once thought, if we act first on our cognitive skills, we can slow the decline of this virtuous circle. "This study backs up our theory that the brain has to make a real effort to get out of a sedentary lifestyle and that by working on cognitive capacities, physical activity will follow," says Cheval by way of conclusion.
Read more at Science Daily
The literature in this area has been looking at the impact of physical activity on cognitive skills for a number of years. "Correlations have been established between these two factors, particularly in terms of memory, but also regarding the growth and survival of new neurons," begins Boris Cheval, a researcher at UNIGE's Swiss Centre for Affective Sciences (CISA). "But we have never yet formally tested which comes first: does physical activity prevent a decline in cognitive skills or vice versa? That's what we wanted to verify."
What came first: the chicken or the egg?
Earlier studies based on the correlation between physical activity and cognitive skills postulated that the former prevent the decline of the latter. "But what if this research only told half the story? That's what recent studies suggest, since they demonstrate that our brain is involved when it comes to engaging in physical activity," continues the Geneva-based researcher.
The UNIGE researchers tested the two possible options formally using data from the SHARE survey (Survey of Health, Aging and Retirement in Europe), a European-wide socio-economic database covering over 25 countries. "The cognitive abilities and level of physical activity of 105,206 adults aged 50 to 90 were tested every two years over a 12-year period," explains Matthieu Boisgontier, a researcher at the Lives Swiss National Centre of Competence in Research (NCCR Lives). Cognitive abilities were measured using a verbal fluency test (naming as many animals as possible in 60 seconds) and a memory test (memorising 10 words and reciting them afterwards). Physical activity was measured on a scale of 1 ("Never") to 4 ("More than once a week").
The Geneva researchers employed this data in three separate statistical models. In the first, they looked at whether physical activity predicted the change in cognitive skills over time; in the second, whether cognitive skills predicted the change in physical activity; and in the third, they tested the two possibilities bidirectionally. "Thanks to a statistical index, we found that the second model adjusted the most precisely to the data of the participants," says Cheval. The study demonstrates, therefore, that cognitive capacities mainly influence physical activity and not vice versa, as the literature to date had postulated. "Obviously, it's a virtuous cycle, since physical activity also influences our cognitive capacities. But, in light of these new findings, it does so to a lesser extent," points out Boisgontier.
Slowing down an inevitable decline
From the age of 50, the decline in physical and cognitive abilities is inevitable. However, these results indicate that, contrary to what was once thought, if we act first on our cognitive skills, we can slow the decline of this virtuous circle. "This study backs up our theory that the brain has to make a real effort to get out of a sedentary lifestyle and that by working on cognitive capacities, physical activity will follow," says Cheval by way of conclusion.
Read more at Science Daily
Study shows how diligent we have to be to keep surfaces germ-free
During the COVID-19 pandemic, every frequently touched surface outside our home seems as dangerous as a hot pot right out of the oven. We won't get burned if we touch it, but we might get infected with a potentially dangerous virus.
A recent study suggests that even organized efforts to clean surfaces can fall short, a reminder for us all that keeping our surroundings clean may require some additional work.
For 5 ½ weeks, researchers tagged surfaces of a small-animal veterinary practice daily with a fluorescent dye visible only under black light. They checked tagged surfaces 24 hours later to see if the marks were showing. Surfaces were considered cleaned if the dye was completely removed.
Results showed that overall, only half of all surfaces were adequately cleaned during the study period. Human-touch surfaces -- such as medical instruments, dog run handles, and computer mice and keyboards -- were cleaned less frequently than areas touched primarily by animals. The results were similar to studies from other veterinary clinics.
The researchers recommended creating checklists of surfaces that need to be regularly cleaned and educating all staff on the importance of proper cleaning to protect animal and human health.
"The concept of infectious diseases is around us all the time, but now it's more important than ever to take steps to protect ourselves," said senior study author Jason Stull, assistant professor of veterinary preventive medicine at The Ohio State University.
"A recent study concluded the coronavirus causing COVID-19 has the ability to survive on certain types of surfaces for hours to a few days. At veterinary practices, other businesses and certainly human hospitals, surface cleaning and disinfection is extremely important. People come in and may contaminate an area and that area potentially can serve as a source of infection for other people."
The study is published in the February issue of the Journal of Small Animal Practice.
Stull specializes in veterinary infection control, including prevention of diseases that animals can share with each other or pass to humans -- such as Salmonella, E. coli and parasites.
For the current work, Stull and colleagues assessed almost 5,000 surfaces over the course of the study. On average, 50 percent of surfaces were cleaned, with broad variations by type of surface and hospital location. The human-touch surfaces were the least likely to be cleaned.
The study assessed everyday cleaning practices in a place where people spend lots of time with different animals and different people. It's not too much of a stretch to apply some lessons to what we're experiencing now with COVID-19, Stull said.
"Plenty of industries and groups outside of human health care have ramped up their efforts to clean and disinfect common-touch surfaces. The take-home messages from our study can have important parallels for others, such as other veterinary clinics, but also groups such as grocery stores.
"Our study also highlights that, despite our best efforts, 100 percent cleaning and disinfection is unlikely to occur. This is important to remember, as regardless of where you visit, it's also best to assume surfaces may be contaminated -- and before you come back into your home, you should follow the recommendations to clean your hands and clean items you've handled."
At home, Stull said, it makes sense to concentrate on cleaning common-touch surfaces like doorknobs and countertops.
"For the average person, it's thinking about your list of things in your own home and ensuring that in some way that you're actually hitting those pieces with reasonable effort," he said.
On a normal day, people who have touched commonly shared surfaces should wash their hands before eating or scratching their noses. But will we remain diligent about this level of personal cleanliness -- and community health -- once the worst of the coronavirus threat is behind us?
"People have a tendency to swing from extremes," Stull said. "Changing the innate behaviors of people is always difficult, and we've struggled in human and veterinary health care to change these everyday practices.
"The hard part is continuing these efforts. When we get to the end of this, and at some point that will happen, you will likely see people revert back to their norm. What we need is a culture shift, so people recognize that infection control through hand-washing and thorough cleaning of shared surfaces is a critically important thing we can all do all the time, and it has measurable impact."
Read more at Science Daily
A recent study suggests that even organized efforts to clean surfaces can fall short, a reminder for us all that keeping our surroundings clean may require some additional work.
For 5 ½ weeks, researchers tagged surfaces of a small-animal veterinary practice daily with a fluorescent dye visible only under black light. They checked tagged surfaces 24 hours later to see if the marks were showing. Surfaces were considered cleaned if the dye was completely removed.
Results showed that overall, only half of all surfaces were adequately cleaned during the study period. Human-touch surfaces -- such as medical instruments, dog run handles, and computer mice and keyboards -- were cleaned less frequently than areas touched primarily by animals. The results were similar to studies from other veterinary clinics.
The researchers recommended creating checklists of surfaces that need to be regularly cleaned and educating all staff on the importance of proper cleaning to protect animal and human health.
"The concept of infectious diseases is around us all the time, but now it's more important than ever to take steps to protect ourselves," said senior study author Jason Stull, assistant professor of veterinary preventive medicine at The Ohio State University.
"A recent study concluded the coronavirus causing COVID-19 has the ability to survive on certain types of surfaces for hours to a few days. At veterinary practices, other businesses and certainly human hospitals, surface cleaning and disinfection is extremely important. People come in and may contaminate an area and that area potentially can serve as a source of infection for other people."
The study is published in the February issue of the Journal of Small Animal Practice.
Stull specializes in veterinary infection control, including prevention of diseases that animals can share with each other or pass to humans -- such as Salmonella, E. coli and parasites.
For the current work, Stull and colleagues assessed almost 5,000 surfaces over the course of the study. On average, 50 percent of surfaces were cleaned, with broad variations by type of surface and hospital location. The human-touch surfaces were the least likely to be cleaned.
The study assessed everyday cleaning practices in a place where people spend lots of time with different animals and different people. It's not too much of a stretch to apply some lessons to what we're experiencing now with COVID-19, Stull said.
"Plenty of industries and groups outside of human health care have ramped up their efforts to clean and disinfect common-touch surfaces. The take-home messages from our study can have important parallels for others, such as other veterinary clinics, but also groups such as grocery stores.
"Our study also highlights that, despite our best efforts, 100 percent cleaning and disinfection is unlikely to occur. This is important to remember, as regardless of where you visit, it's also best to assume surfaces may be contaminated -- and before you come back into your home, you should follow the recommendations to clean your hands and clean items you've handled."
At home, Stull said, it makes sense to concentrate on cleaning common-touch surfaces like doorknobs and countertops.
"For the average person, it's thinking about your list of things in your own home and ensuring that in some way that you're actually hitting those pieces with reasonable effort," he said.
On a normal day, people who have touched commonly shared surfaces should wash their hands before eating or scratching their noses. But will we remain diligent about this level of personal cleanliness -- and community health -- once the worst of the coronavirus threat is behind us?
"People have a tendency to swing from extremes," Stull said. "Changing the innate behaviors of people is always difficult, and we've struggled in human and veterinary health care to change these everyday practices.
"The hard part is continuing these efforts. When we get to the end of this, and at some point that will happen, you will likely see people revert back to their norm. What we need is a culture shift, so people recognize that infection control through hand-washing and thorough cleaning of shared surfaces is a critically important thing we can all do all the time, and it has measurable impact."
Read more at Science Daily
Singapore modelling study estimates impact of physical distancing on reducing spread of COVID-19
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| Social distancing concept with domino pieces. |
While less effective than the combined approach, quarantine plus workplace measures presented the next best option for reducing SARS-CoV-2 cases, followed by quarantine plus school closure, and then quarantine only. All intervention scenarios were more effective at reducing cases than no intervention.
The study, published in The Lancet Infectious Diseases journal, is the first of its kind to investigate using these options for early intervention in Singapore using simulation. Despite heightened surveillance and isolation of individuals suspected to have COVID-19 and confirmed cases, the risk is ongoing, with the number of cases continuing to increase in Singapore. Schools have not been closed, and workplace distancing is recommended, but it is not national policy [correct as of 23.03.2020].
The study found that the combined approach could prevent a national outbreak at relatively low levels of infectivity (basic reproductivity value (R0) = 1.5), but at higher infectivity scenarios (R0 = 2.0 (considered moderate and likely) and R0 = 2.5 (considered high)), outbreak prevention becomes considerably more challenging because although effective at reducing infections, transmission events still occur.
Dr Alex R Cook, National University of Singapore, said: "Should local containment measures, such as preventing disease spread through contact tracing efforts and, more recently, not permitting short-term visitors, be unsuccessful, the results of this study provide policy makers in Singapore and other countries with evidence to begin the implementation of enhanced outbreak control measures that could mitigate or reduce local transmission rates if deployed effectively and in a timely manner."
To assess the potential impact of interventions on outbreak size, should local containment fail, authors developed an individual-based influenza epidemic simulation model, which accounted for demography, individual movement, and social contact rates in workplaces, schools, and homes, to estimate the likelihood of human-to-human transmission of SARS-CoV-2. Model parameters included how infectious an individual is over time, the proportion of the population assumed to be asymptomatic (7.5%), the cumulative distribution function for the mean incubation period (with the virus that causes SARS and the virus that causes COVID-19having the same mean incubation period of 5.3 days), and the duration of hospital stay after symptom onset (3.5 days).
Using this model, authors estimated the cumulative number of SARS-CoV-2 infections at 80 days, after detection of 100 cases of community transmission. Three values for the basic reproduction number (R0) were chosen for the infectiousness parameter, including relatively low (R0=1.5), moderate and likely (R0=2.0), and high transmissibility (R0=2.5). The basic reproduction numbers were selected based on analyses of data from people with COVID-19 in Wuhan, China.
In addition to a baseline scenario, which included no interventions, four intervention scenarios were proposed for implementation after failure of local containment: 1) isolation of infected individuals and quarantine of their family members (quarantine); 2) quarantine plus immediate school closure for 2 weeks; 3) quarantine plus immediate workplace distancing, in which 50% of the workforce is encouraged to work from home for 2 weeks; 4) a combination of quarantine, immediate school closure, and workplace distancing. These interventions follow some policy options currently being undertaken (quarantine and some workforce distancing) by the Singaporean Ministry of Health, as standard interventions for respiratory virus control.
For the baseline scenario, when R0 was 1.5, the median cumulative number of infections at day 80 was 279,000, corresponding to 7.4% of the resident population of Singapore. The median number of infections increased with higher infectivity: 727,000 cases when R0 was 2.0, corresponding to 19.3% of the Singaporean population, and 1,207,000 cases when R0 was 2.5, corresponding to 32% of the Singaporean population.
Compared with the baseline scenario, the combined intervention was the most effective, reducing the estimated median number of infections by 99.3% when R0 was 1.5 (resulting in an estimated 1,800 cases). However, at higher infectivity scenarios, outbreak prevention becomes considerably more challenging. For the combined approach scenario, a median of 50,000 cases were estimated at R0 of 2.0 (a reduction of 93.0% compared to baseline) and 258,000 cases at R0 of 2.5 (a reduction of 78.2% compared to baseline).
Authors also explored the potential impact if the proportion of asymptomatic cases in the population was greater than 7.5% (the proportion of people who are able to transmit despite having no or mild symptoms). Even at a low infectivity (when the R0 was 1.5 or lower), a high asymptomatic proportion presents challenges. Assuming increasing asymptomatic proportions up to 50·0%, up to 277,000 infections were estimated to occur at day 80 with the combined intervention, relative to 1,800 for the baseline at R0 = 1.5.
Dr Alex R Cook added: "If the preventive effect of these interventions reduces considerably due to higher asymptomatic proportions, more pressure will be placed on the quarantining and treatment of infected individuals, which could become unfeasible when the number of infected individuals exceeds the capacity of health-care facilities. At higher asymptomatic rates, public education and case management become increasingly important, with a need to develop vaccines and existing drug therapies."
The authors note several limitations in their study, including dated census population data, impact of migrant movement, the impact of seeding of imported cases (transmissions originating from outside of Singapore) the dynamics of contact patterns between individuals, and other unforeseen factors. Of note, epidemiological characteristics of COVID-19 remain uncertain in terms of the transmission and infectivity profile of the virus; therefore, estimates of the time between symptom onset and admission to hospital, how infectious an individual is over time, and the asymptomatic rate were based on SARS-CoV.
Read more at Science Daily
Mar 24, 2020
Commonly used mouthwash could make saliva significantly more acidic, change microbes
The first study looking at the effect of chlorhexidine mouthwash on the entire oral microbiome has found its use significantly increases the abundance of lactate-producing bacteria that lower saliva pH, and may increase the risk of tooth damage.
A team led by Dr Raul Bescos from the University of Plymouth's Faculty of Health gave a placebo mouthwash to subjects for seven days, followed by seven days of a chlorhexidine mouthwash.
At the end of each period, the researchers carried out an analysis of the abundance and diversity of the bacteria in the mouth -- the oral microbiome -- as well as measuring pH, saliva buffering capacity (the ability to neutralise acids in the mouth), lactate, glucose, nitrate and nitrite concentrations.
The research, published in Scientific Reports today, found using chlorhexidine mouthwash over the seven days led to a greater abundance of species within the families of Firmicutes and Proteobacteria, and fewer Bacteroidetes, TM7 and Fusobacteria. This change was associated with an increase in acidity, seen in lower salivary pH and buffering capacity.
Overall, chlorhexidine was found to reduce microbial diversity in the mouth, although the authors cautioned more research was needed to determine if this reduction in diversity itself increased the risk of oral disease.
One of the primary roles of saliva is to maintain a neutral pH in the mouth, as acidity levels fluctuate as a result of eating and drinking. If saliva pH gets too low, damage can occur to the teeth and mucosa -- tissue surrounding the teeth and on the inside of the mouth.
The research also confirmed findings from previous studies indicating that chlorhexidine disrupted the ability of oral bacteria to turn nitrate into nitrite, a key molecule for reducing blood pressure. Lower saliva and blood plasma nitrite concentrations were found after using chlorhexidine mouthwash, followed by a trend of increased systolic blood pressure. The findings supported earlier research led by the University that showed the blood pressure-lowering effect of exercise is significantly reduced when people rinse their mouths with antibacterial mouthwash rather than water.
Dr Bescos said: "There is a surprising lack of knowledge and literature behind the use of these products. Chlorhexidine mouthwash is widely used but research has been limited to its effect on a small number of bacteria linked to particular oral diseases, and most has been carried out in vitro.
"We believe this is the first study to look at the impact of 7-day use on the whole oral microbiome in human subjects."
Dr Zoe Brookes and Dr Louise Belfield, Lecturers in the Peninsula Dental School at the University of Plymouth, are co-authors of the study.
Dr Belfield said: "We have significantly underestimated the complexity of the oral microbiome and the importance of oral bacteria in the past. Traditionally the view has been that bacteria are bad and cause diseases. But we now know that the majority of bacteria -- whether in the mouth or the gut -- are essential for sustaining human health."
Dr Brookes added: "As dental clinicians, we need more information on how mouthwashes alter the balance of oral bacteria, so we can prescribe them correctly. This paper is an important first step in achieving this.
Read more at Science Daily
A team led by Dr Raul Bescos from the University of Plymouth's Faculty of Health gave a placebo mouthwash to subjects for seven days, followed by seven days of a chlorhexidine mouthwash.
At the end of each period, the researchers carried out an analysis of the abundance and diversity of the bacteria in the mouth -- the oral microbiome -- as well as measuring pH, saliva buffering capacity (the ability to neutralise acids in the mouth), lactate, glucose, nitrate and nitrite concentrations.
The research, published in Scientific Reports today, found using chlorhexidine mouthwash over the seven days led to a greater abundance of species within the families of Firmicutes and Proteobacteria, and fewer Bacteroidetes, TM7 and Fusobacteria. This change was associated with an increase in acidity, seen in lower salivary pH and buffering capacity.
Overall, chlorhexidine was found to reduce microbial diversity in the mouth, although the authors cautioned more research was needed to determine if this reduction in diversity itself increased the risk of oral disease.
One of the primary roles of saliva is to maintain a neutral pH in the mouth, as acidity levels fluctuate as a result of eating and drinking. If saliva pH gets too low, damage can occur to the teeth and mucosa -- tissue surrounding the teeth and on the inside of the mouth.
The research also confirmed findings from previous studies indicating that chlorhexidine disrupted the ability of oral bacteria to turn nitrate into nitrite, a key molecule for reducing blood pressure. Lower saliva and blood plasma nitrite concentrations were found after using chlorhexidine mouthwash, followed by a trend of increased systolic blood pressure. The findings supported earlier research led by the University that showed the blood pressure-lowering effect of exercise is significantly reduced when people rinse their mouths with antibacterial mouthwash rather than water.
Dr Bescos said: "There is a surprising lack of knowledge and literature behind the use of these products. Chlorhexidine mouthwash is widely used but research has been limited to its effect on a small number of bacteria linked to particular oral diseases, and most has been carried out in vitro.
"We believe this is the first study to look at the impact of 7-day use on the whole oral microbiome in human subjects."
Dr Zoe Brookes and Dr Louise Belfield, Lecturers in the Peninsula Dental School at the University of Plymouth, are co-authors of the study.
Dr Belfield said: "We have significantly underestimated the complexity of the oral microbiome and the importance of oral bacteria in the past. Traditionally the view has been that bacteria are bad and cause diseases. But we now know that the majority of bacteria -- whether in the mouth or the gut -- are essential for sustaining human health."
Dr Brookes added: "As dental clinicians, we need more information on how mouthwashes alter the balance of oral bacteria, so we can prescribe them correctly. This paper is an important first step in achieving this.
Read more at Science Daily
Unprecedented preservation of fossil feces from the La Brea Tar Pits
While Rancho La Brea, commonly known as the La Brea Tar Pits, is famous for its thousands of bones of large extinct mammals, big insights are coming from small fossils, thanks to new excavation and chemical techniques.
Today, a team of researchers from La Brea Tar Pits, the University of Oklahoma and the University of California Irvine report the first coprolites -- or fossil feces -- ever discovered in an asphaltic -- or tar pit -- context. These hundreds of fossilized rodent pellets were found during the excavation of a parking garage for the Los Angeles County Museum of Art in Hancock Park in 2016, which had also yielded the more traditional La Brea fossils, such as extinct mammoths, dire wolves and saber-toothed cats.
Alexis Mychajliw, a postdoctoral research associate at OU, is the lead author of the study. The details of the research team's findings were published today in Scientific Reports.
"It's incredible that after more than a century of excavation and study, we are still unearthing new types of fossils from La Brea's treasure trove of deposits," said Emily Lindsey, assistant curator at La Brea Tar Pits. "These tiny finds may lead to big discoveries about the climate and ecosystems of Ice Age Los Angeles."
Researchers were skeptical at first, given the abundance of urban rats in the area.
"We noted the occasional rodent fecal pellet in the processed matrix before, but it was easy to explain it away as modern contamination," said Laura Tewksbury, senior preparator at La Brea Tar Pits.
But, with more and more pellets appearing encased in asphalt, Tewksbury recalled, "We stared at the sheer number of pellets in silence for a minute, before looking at each other and stating, 'There's just no way that much is contamination.'"
Indeed, radiocarbon dates generated at UC Irvine would confirm the pellets were ~50,000 years old.
Rancho La Brea has been associated with the image of big animals getting stuck in "tar pits," or shallow, sticky asphalt pools, with carnivores attracted en masse by struggling herbivore prey. But these coprolites tell a new story of how fossils can be preserved at Rancho La Brea.
"The intact nature and density of the fossils require a taphonomic explanation other than entrapment. The preservation is more likely the result of an asphalt seep overtaking an existing rodent nest," noted Karin Rice, preparator at La Brea Tar Pits.
Using a suite of cutting-edge tools, including stable isotope analysis and scanning electron microscopy, the researchers demonstrated that the fecal pellets were associated with beautifully preserved twigs, leaves, and seeds, apparently as part of an intact nest made by a woodrat. Woodrats -- also known as packrats -- are well-known in the paleontological community for their hoarding behavior that produces massive nests that can be preserved for thousands of years. Slices of plant material from these nests, in turn, represent snapshots of vegetation and climate conditions of the past.
Read more at Science Daily
Today, a team of researchers from La Brea Tar Pits, the University of Oklahoma and the University of California Irvine report the first coprolites -- or fossil feces -- ever discovered in an asphaltic -- or tar pit -- context. These hundreds of fossilized rodent pellets were found during the excavation of a parking garage for the Los Angeles County Museum of Art in Hancock Park in 2016, which had also yielded the more traditional La Brea fossils, such as extinct mammoths, dire wolves and saber-toothed cats.
Alexis Mychajliw, a postdoctoral research associate at OU, is the lead author of the study. The details of the research team's findings were published today in Scientific Reports.
"It's incredible that after more than a century of excavation and study, we are still unearthing new types of fossils from La Brea's treasure trove of deposits," said Emily Lindsey, assistant curator at La Brea Tar Pits. "These tiny finds may lead to big discoveries about the climate and ecosystems of Ice Age Los Angeles."
Researchers were skeptical at first, given the abundance of urban rats in the area.
"We noted the occasional rodent fecal pellet in the processed matrix before, but it was easy to explain it away as modern contamination," said Laura Tewksbury, senior preparator at La Brea Tar Pits.
But, with more and more pellets appearing encased in asphalt, Tewksbury recalled, "We stared at the sheer number of pellets in silence for a minute, before looking at each other and stating, 'There's just no way that much is contamination.'"
Indeed, radiocarbon dates generated at UC Irvine would confirm the pellets were ~50,000 years old.
Rancho La Brea has been associated with the image of big animals getting stuck in "tar pits," or shallow, sticky asphalt pools, with carnivores attracted en masse by struggling herbivore prey. But these coprolites tell a new story of how fossils can be preserved at Rancho La Brea.
"The intact nature and density of the fossils require a taphonomic explanation other than entrapment. The preservation is more likely the result of an asphalt seep overtaking an existing rodent nest," noted Karin Rice, preparator at La Brea Tar Pits.
Using a suite of cutting-edge tools, including stable isotope analysis and scanning electron microscopy, the researchers demonstrated that the fecal pellets were associated with beautifully preserved twigs, leaves, and seeds, apparently as part of an intact nest made by a woodrat. Woodrats -- also known as packrats -- are well-known in the paleontological community for their hoarding behavior that produces massive nests that can be preserved for thousands of years. Slices of plant material from these nests, in turn, represent snapshots of vegetation and climate conditions of the past.
Read more at Science Daily
Christmas Island discovery redraws map of life
The world's animal distribution map will need to be redrawn and textbooks updated, after researchers discovered the existence of 'Australian' species on Christmas Island.
The University of Queensland's Professor Jonathan Aitchison said the finding revises the long-held understanding of the location of one of biology and geography's most significant barriers -- the Wallace line.
"The Wallace line -- named after its discoverer Alfred Russel Wallace -- delineates major biological division separating the species with Asian origins from those with Australasian ones," Professor Aitchison said.
"It runs along the narrow seaways separating Bali from Lombok, and Borneo from Sulawesi.
"To the west are the tigers, elephants, rhinoceroses and orang-utans of Eurasia and to the east, the marsupials and monotremes that are synonymous with Australia."
Working 1000 kilometres west of the conventional trace of Wallace line, on Christmas Island, Professor Aitchison and his colleagues, Dr Jason Ali from the University of Hong Kong and Professor Shai Meiri from the University of Tel Aviv, noted species with Australasian origins.
"Unexpectedly, half of Christmas Island's land mammal and land reptile species -- two rats, two skinks and one gecko -- have a genetic heritage to Australia's side of the divide," Dr Ali said.
"It was a highly surprising discovery.
"The ancestors of these species would have most likely have been washed over on uprooted trees of vegetation mats and transported in by a major oceanic current known as the Indonesian Throughflow.
"The Indonesian Throughflow is part of the global heat conveyor belt, and follows deeper waters that delineate the Wallace line.
"It's caused by the westernmost Pacific Ocean surface topography being slightly higher than its Indian Ocean counterpart.
"That's right -- it's a little mind-bending -- but the 'sea-level' varies slightly in different parts of the world."
Professor Aitchison said the species' journey must have occurred within the last five million years, as this is when Christmas Island emerged to form a new landmass.
"Christmas Island existed as a coral atoll from about 40 to 17 million years ago," Professor Aitchison said.
"But in response to a tectonics phenomenon originally described by Darwin, it subsided beneath the ocean surface and disappeared.
"It re-surfaced only five million years ago thanks to some flexing tectonic plates -- 300 to 350 kilometres to the south of where it is now located -- from then on land plants and animals could begin to establish new populations.
"Christmas Island is a strange and unique place, not just because of its geological history, but also its biological history.
Read more at Science Daily
The University of Queensland's Professor Jonathan Aitchison said the finding revises the long-held understanding of the location of one of biology and geography's most significant barriers -- the Wallace line.
"The Wallace line -- named after its discoverer Alfred Russel Wallace -- delineates major biological division separating the species with Asian origins from those with Australasian ones," Professor Aitchison said.
"It runs along the narrow seaways separating Bali from Lombok, and Borneo from Sulawesi.
"To the west are the tigers, elephants, rhinoceroses and orang-utans of Eurasia and to the east, the marsupials and monotremes that are synonymous with Australia."
Working 1000 kilometres west of the conventional trace of Wallace line, on Christmas Island, Professor Aitchison and his colleagues, Dr Jason Ali from the University of Hong Kong and Professor Shai Meiri from the University of Tel Aviv, noted species with Australasian origins.
"Unexpectedly, half of Christmas Island's land mammal and land reptile species -- two rats, two skinks and one gecko -- have a genetic heritage to Australia's side of the divide," Dr Ali said.
"It was a highly surprising discovery.
"The ancestors of these species would have most likely have been washed over on uprooted trees of vegetation mats and transported in by a major oceanic current known as the Indonesian Throughflow.
"The Indonesian Throughflow is part of the global heat conveyor belt, and follows deeper waters that delineate the Wallace line.
"It's caused by the westernmost Pacific Ocean surface topography being slightly higher than its Indian Ocean counterpart.
"That's right -- it's a little mind-bending -- but the 'sea-level' varies slightly in different parts of the world."
Professor Aitchison said the species' journey must have occurred within the last five million years, as this is when Christmas Island emerged to form a new landmass.
"Christmas Island existed as a coral atoll from about 40 to 17 million years ago," Professor Aitchison said.
"But in response to a tectonics phenomenon originally described by Darwin, it subsided beneath the ocean surface and disappeared.
"It re-surfaced only five million years ago thanks to some flexing tectonic plates -- 300 to 350 kilometres to the south of where it is now located -- from then on land plants and animals could begin to establish new populations.
"Christmas Island is a strange and unique place, not just because of its geological history, but also its biological history.
Read more at Science Daily
How squid communicate in the dark
In the frigid waters 1,500 feet below the surface of the Pacific Ocean, hundreds of human-sized Humboldt squid feed on a patch of finger-length lantern fish. Zipping past each other, the predators move with exceptional precision, never colliding or competing for prey.
How do they establish such order in the near-darkness of the ocean's twilight zone?
The answer, according to researchers from Stanford University and the Monterey Bay Aquarium Research Institute (MBARI) may be visual communication. Like the illuminated words on an e-book reader, these researchers suggest that the squid's ability to subtly glow -- using light-producing organs in their muscles -- can create a backlight for shifting pigmentation patterns on their skin. The creatures may be using these changing patterns to signal one another.
The research is published March 23 in the journal Proceedings of the National Academy of Sciences.
"Many squid live in fairly shallow water and don't have these light-producing organs, so it's possible this is a key evolutionary innovation for being able to inhabit the open ocean," said Benjamin Burford, a graduate student in biology in the School of Humanities and Sciences at Stanford and lead author of the paper. "Maybe they need this ability to glow and display these pigmentation patterns to facilitate group behaviors in order to survive out there."
Seeing the deep sea
Humboldt squid behavior is nearly impossible to study in captivity, so researchers must meet them where they live. For this research, Bruce Robison of MBARI, who is senior author of the paper, captured footage of Humboldt squid off the coast of California using remotely operated vehicles (ROVs), or unmanned, robotic submarines.
While the ROVs could record the squid's skin patterning, the lights the cameras required were too bright to record their subtle glow, so the researchers couldn't test their backlighting hypothesis directly. Instead, they found supporting evidence for it in their anatomical studies of captured squid.
Using the ROV footage, the researchers analyzed how individual squid behaved when they were feeding versus when they were not. They also paid attention to how these behaviors changed depending on the number of other squid in the immediate area -- after all, people communicate differently if they are speaking with friends versus a large audience.
The footage confirmed that squid's pigmentation patterns do seem to relate to specific contexts. Some patterns were detailed enough to imply that the squid may be communicating precise messages -- such as "that fish over there is mine." There was also evidence that their behaviors could be broken down into distinct units that the squid recombine to form different messages, like letters in the alphabet. Still, the researchers emphasize that it is too early to conclude whether the squid communications constitute a human-like language.
"Right now, as we speak, there are probably squid signaling each other in the deep ocean," said Burford, who is affiliated with the Denny lab at Stanford's Hopkins Marine Station. "And who knows what kind of information they're saying and what kind of decisions they're making based on that information?"
Although these squid can see well in dim light, their vision is probably not especially sharp, so the researchers speculated that the light-producing organs help facilitate the squid's visual communications by boosting the contrast for their skin patterning. They investigated this hypothesis by mapping where these light organs are located in Humboldt squid and comparing that to where the most detailed skin patterns appear on the creatures.
They found that the areas where the illuminating organs were most densely packed -- such as a small area between the squid's eyes and the thin edge of their fins -- corresponded to those where the most intricate patterns occurred.
Familiar aliens
In the time since the squid were filmed, ROV technology has advanced enough that the team could directly view their backlighting hypothesis in action the next time the squid are observed in California. Burford would also like to create some sort of virtual squid that the team could project in front of real squid to see how they respond to the cyber-squid's patterns and movements.
The researchers are thrilled with what they have found so far but eager to do further research in the deep sea. Although studying the inhabitants of the deep sea where they live can be a frustratingly difficult endeavor, this research has the potential to inform a new understanmetimes think of squid as crazy lifeforms living in this alien world but we have a lot in common -- they live in groups, they're social, they talkding of how life functions.
"We so to one another," Burford said. "Researching their behavior and that of other residents of the deep sea is important for learning how life may exist in alien environments, but it also tells us more generally about the strategies used in extreme environments on our own planet."
Read more at Science Daily
How do they establish such order in the near-darkness of the ocean's twilight zone?
The answer, according to researchers from Stanford University and the Monterey Bay Aquarium Research Institute (MBARI) may be visual communication. Like the illuminated words on an e-book reader, these researchers suggest that the squid's ability to subtly glow -- using light-producing organs in their muscles -- can create a backlight for shifting pigmentation patterns on their skin. The creatures may be using these changing patterns to signal one another.
The research is published March 23 in the journal Proceedings of the National Academy of Sciences.
"Many squid live in fairly shallow water and don't have these light-producing organs, so it's possible this is a key evolutionary innovation for being able to inhabit the open ocean," said Benjamin Burford, a graduate student in biology in the School of Humanities and Sciences at Stanford and lead author of the paper. "Maybe they need this ability to glow and display these pigmentation patterns to facilitate group behaviors in order to survive out there."
Seeing the deep sea
Humboldt squid behavior is nearly impossible to study in captivity, so researchers must meet them where they live. For this research, Bruce Robison of MBARI, who is senior author of the paper, captured footage of Humboldt squid off the coast of California using remotely operated vehicles (ROVs), or unmanned, robotic submarines.
While the ROVs could record the squid's skin patterning, the lights the cameras required were too bright to record their subtle glow, so the researchers couldn't test their backlighting hypothesis directly. Instead, they found supporting evidence for it in their anatomical studies of captured squid.
Using the ROV footage, the researchers analyzed how individual squid behaved when they were feeding versus when they were not. They also paid attention to how these behaviors changed depending on the number of other squid in the immediate area -- after all, people communicate differently if they are speaking with friends versus a large audience.
The footage confirmed that squid's pigmentation patterns do seem to relate to specific contexts. Some patterns were detailed enough to imply that the squid may be communicating precise messages -- such as "that fish over there is mine." There was also evidence that their behaviors could be broken down into distinct units that the squid recombine to form different messages, like letters in the alphabet. Still, the researchers emphasize that it is too early to conclude whether the squid communications constitute a human-like language.
"Right now, as we speak, there are probably squid signaling each other in the deep ocean," said Burford, who is affiliated with the Denny lab at Stanford's Hopkins Marine Station. "And who knows what kind of information they're saying and what kind of decisions they're making based on that information?"
Although these squid can see well in dim light, their vision is probably not especially sharp, so the researchers speculated that the light-producing organs help facilitate the squid's visual communications by boosting the contrast for their skin patterning. They investigated this hypothesis by mapping where these light organs are located in Humboldt squid and comparing that to where the most detailed skin patterns appear on the creatures.
They found that the areas where the illuminating organs were most densely packed -- such as a small area between the squid's eyes and the thin edge of their fins -- corresponded to those where the most intricate patterns occurred.
Familiar aliens
In the time since the squid were filmed, ROV technology has advanced enough that the team could directly view their backlighting hypothesis in action the next time the squid are observed in California. Burford would also like to create some sort of virtual squid that the team could project in front of real squid to see how they respond to the cyber-squid's patterns and movements.
The researchers are thrilled with what they have found so far but eager to do further research in the deep sea. Although studying the inhabitants of the deep sea where they live can be a frustratingly difficult endeavor, this research has the potential to inform a new understanmetimes think of squid as crazy lifeforms living in this alien world but we have a lot in common -- they live in groups, they're social, they talkding of how life functions.
"We so to one another," Burford said. "Researching their behavior and that of other residents of the deep sea is important for learning how life may exist in alien environments, but it also tells us more generally about the strategies used in extreme environments on our own planet."
Read more at Science Daily
Mar 23, 2020
Ancestor of all animals identified in Australian fossils
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| Primordial ocean floor concept |
The tiny, wormlike creature, named Ikaria wariootia, is the earliest bilaterian, or organism with a front and back, two symmetrical sides, and openings at either end connected by a gut. The paper is published today in Proceedings of the National Academy of Sciences.
The earliest multicellular organisms, such as sponges and algal mats, had variable shapes. Collectively known as the Ediacaran Biota, this group contains the oldest fossils of complex, multicellular organisms. However, most of these are not directly related to animals around today, including lily pad-shaped creatures known as Dickinsonia that lack basic features of most animals, such as a mouth or gut.
The development of bilateral symmetry was a critical step in the evolution of animal life, giving organisms the ability to move purposefully and a common, yet successful way to organize their bodies. A multitude of animals, from worms to insects to dinosaurs to humans, are organized around this same basic bilaterian body plan.
Evolutionary biologists studying the genetics of modern animals predicted the oldest ancestor of all bilaterians would have been simple and small, with rudimentary sensory organs. Preserving and identifying the fossilized remains of such an animal was thought to be difficult, if not impossible.
For 15 years, scientists agreed that fossilized burrows found in 555 million-year-old Ediacaran Period deposits in Nilpena, South Australia, were made by bilaterians. But there was no sign of the creature that made the burrows, leaving scientists with nothing but speculation.
Scott Evans, a recent doctoral graduate from UC Riverside; and Mary Droser, a professor of geology, noticed miniscule, oval impressions near some of these burrows. With funding from a NASA exobiology grant, they used a three-dimensional laser scanner that revealed the regular, consistent shape of a cylindrical body with a distinct head and tail and faintly grooved musculature. The animal ranged between 2-7 millimeters long and about 1-2.5 millimeters wide, with the largest the size and shape of a grain of rice -- just the right size to have made the burrows.
"We thought these animals should have existed during this interval, but always understood they would be difficult to recognize," Evans said. "Once we had the 3D scans, we knew that we had made an important discovery."
The researchers, who include Ian Hughes of UC San Diego and James Gehling of the South Australia Museum, describe Ikaria wariootia, named to acknowledge the original custodians of the land. The genus name comes from Ikara, which means "meeting place" in the Adnyamathanha language. It's the Adnyamathanha name for a grouping of mountains known in English as Wilpena Pound. The species name comes from Warioota Creek, which runs from the Flinders Ranges to Nilpena Station.
"Burrows of Ikaria occur lower than anything else. It's the oldest fossil we get with this type of complexity," Droser said. "Dickinsonia and other big things were probably evolutionary dead ends. We knew that we also had lots of little things and thought these might have been the early bilaterians that we were looking for."
In spite of its relatively simple shape, Ikaria was complex compared to other fossils from this period. It burrowed in thin layers of well-oxygenated sand on the ocean floor in search of organic matter, indicating rudimentary sensory abilities. The depth and curvature of Ikaria represent clearly distinct front and rear ends, supporting the directed movement found in the burrows.
The burrows also preserve crosswise, "V"-shaped ridges, suggesting Ikaria moved by contracting muscles across its body like a worm, known as peristaltic locomotion. Evidence of sediment displacement in the burrows and signs the organism fed on buried organic matter reveal Ikaria probably had a mouth, anus, and gut.
Read more at Science Daily
Star formation project maps nearby interstellar clouds
Astronomers have captured new, detailed maps of three nearby interstellar gas clouds containing regions of ongoing high-mass star formation. The results of this survey, called the Star Formation Project, will help improve our understanding of the star formation process.
We know that stars such as the Sun are born from interstellar gas clouds. These interstellar gas clouds are difficult to observe in visible light, but emit strong radio wavelength, which can be observed by the Nobeyama 45-m Radio Telescope in Japan. A research team led by Fumitaka Nakamura, an Assistant Professor at the National Astronomical Observatory of Japan (NAOJ), used the telescope to create detailed radio maps of interstellar gas clouds, the birthplaces of stars. The team including members from NAOJ, the University of Tokyo, Tokyo Gakugei University, Ibaraki University, Otsuma Women's University, Niigata University, Nagoya City University, and other universities, will use the observational data to investigate the star formation process.
The team targeted three interstellar clouds: the Orion A, Aquila Rift, and M17 regions. For the Orion A region, the group collaborated with the CARMA interferometer in the United States, combining their data to create the most detailed map ever of the region. The resultant map has a spatial resolution of about 3200 astronomical units. This means that the map can reveal details as small as 60 times the size of the Solar System.
Even the world's most powerful radio telescope, the Atacama Large Millimeter/submillimeter Array (ALMA), could not obtain a similar large-scale map of Orion A because of ALMA's limited field-of-view and observation time constraints. But ALMA can investigate more distant interstellar clouds. Therefore, this large-scale, most-detailed radio map of the Orion A gas cloud obtained by the Star Formation Project is complementary with other observational research.
From Science Daily
We know that stars such as the Sun are born from interstellar gas clouds. These interstellar gas clouds are difficult to observe in visible light, but emit strong radio wavelength, which can be observed by the Nobeyama 45-m Radio Telescope in Japan. A research team led by Fumitaka Nakamura, an Assistant Professor at the National Astronomical Observatory of Japan (NAOJ), used the telescope to create detailed radio maps of interstellar gas clouds, the birthplaces of stars. The team including members from NAOJ, the University of Tokyo, Tokyo Gakugei University, Ibaraki University, Otsuma Women's University, Niigata University, Nagoya City University, and other universities, will use the observational data to investigate the star formation process.
The team targeted three interstellar clouds: the Orion A, Aquila Rift, and M17 regions. For the Orion A region, the group collaborated with the CARMA interferometer in the United States, combining their data to create the most detailed map ever of the region. The resultant map has a spatial resolution of about 3200 astronomical units. This means that the map can reveal details as small as 60 times the size of the Solar System.
Even the world's most powerful radio telescope, the Atacama Large Millimeter/submillimeter Array (ALMA), could not obtain a similar large-scale map of Orion A because of ALMA's limited field-of-view and observation time constraints. But ALMA can investigate more distant interstellar clouds. Therefore, this large-scale, most-detailed radio map of the Orion A gas cloud obtained by the Star Formation Project is complementary with other observational research.
From Science Daily
New genetic editing powers discovered in squid
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| Squid |
The study, led by Isabel C. Vallecillo-Viejo and Joshua Rosenthal at the Marine Biological Laboratory (MBL), Woods Hole, is published this week in Nucleic Acids Research.
The discovery provides another jolt to the "central dogma" of molecular biology, which states that genetic information is passed faithfully from DNA to messenger RNA to the synthesis of proteins. In 2015, Rosenthal and colleagues discovered that squid "edit" their messenger RNA instructions to an extraordinary degree -- orders of magnitude more than humans do -- allowing them to fine-tune the type of proteins that will be produced in the nervous system.
"But we thought all the RNA editing happened in in the nucleus, and then the modified messenger RNAs are exported out to the cell," says Rosenthal, senior author on the present study. "Now we are showing that squid can modify the RNAs out in the periphery of the cell. That means, theoretically, they can modify protein function to meet the localized demands of the cell. That gives them a lot of latitude to tailor the genetic information, as needed." The team also showed that messenger RNAs are edited in the nerve cell's axon at much higher rates than in the nucleus.
In humans, axon dysfunction is associated with many neurological disorders. Insights from the present study could accelerate the efforts of biotech companies that seek to harness this natural RNA editing process in humans for therapeutic benefit.
Scientists from Tel Aviv University and The University of California at Denver collaborated with MBL scientists on the study.
Previously, Rosenthal and colleagues showed that octopus and cuttlefish also rely heavily on mRNA editing to diversify the proteins they can produce in the nervous system. Together with squid, these animals are known for strikingly sophisticated behaviors, relative to other invertebrates.
From Science Daily
East Antarctica's Denman Glacier has retreated almost 3 miles over last 22 years
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| Illustration of Antarctica on Earth from space. |
If fully thawed, the ice in Denman would cause sea levels worldwide to rise about 1.5 meters, almost 5 feet. With this sobering fact in mind, the UCI and NASA JPL scientists have completed the most thorough examination yet of the glacier and surrounding area, uncovering alarming clues about its condition under further global warming.
The team's assessment is the subject of a paper published today in the American Geophysical Union journal Geophysical Research Letters.
"East Antarctica has long been thought to be less threatened, but as glaciers such as Denman have come under closer scrutiny by the cryosphere science community, we are now beginning to see evidence of potential marine ice sheet instability in this region," said co-author Eric Rignot, chair, Donald Bren Professor and Chancellor's Professor of Earth system science at UCI.
"The ice in West Antarctica has been melting faster in recent years, but the sheer size of Denman Glacier means that its potential impact on long-term sea level rise is just as significant," he added.
According to the study, Denman Glacier experienced a cumulative mass loss of 268 billion tons of ice between 1979 and 2017.
Using radar interferometer data from the Italian Space Agency's COSMO-SkyMed satellite system, the researchers more precisely determined Denman's grounding line, the point at which the ice leaves the land and begins to float in the ocean.
"Differential synthetic aperture radar interferometer data from 1996 to 2018 showed us a marked asymmetry in the grounding line retreat at the ice sheet's land-sea interface," said lead author Virginia Brancato, a postdoctoral fellow with NASA JPL who was a postdoctoral scholar at UCI when the study was conducted.
Denman's eastern flank is protected from retreat by a subglacial ridge. But Brancato said that the western flank, which extends roughly 4 kilometers, is characterized by a deep and steep trough with a bed slope conducive to accelerated retreat.
"Because of the shape of the ground beneath Denman's western side, there is potential for rapid and irreversible retreat, and that means substantial increases in global sea levels in the future," she said.
In December, Nature Geoscience published a paper on the BedMachine Antarctica project led by Mathieu Morlighem, UCI associate professor of Earth system science, which revealed that the trough beneath Denman Glacier extends 3,500 meters below sea level, making it the deepest land canyon on Earth.
The UCI and NASA JPL scientists report in the Geophysical Research Letters paper that the bed configuration of Denman is unique in Antarctica's eastern sector. Other major glaciers, such as Totten and Moscow University, feature prograde beds that slope down in the flow direction, providing some measure of stability, Rignot said.
Tracking the state of the floating extension of Denman Glacier, a 24,000-square-kilometer mass that includes the Shackleton Ice Shelf and Denman ice tongue, will be especially important, he added. The researchers used the German Aerospace Center's TanDEM-X satellite in combination with data from COSMO-SkyMed to assess the melt rate of the floating sea ice, learning that the Denman ice tongue has shed mass at a rate of about 3 meters per year, above average compared to other East Antarctic ice shelves.
Read more at Science Daily
Mar 22, 2020
Scientists have discovered the origins of the building blocks of life
Rutgers researchers have discovered the origins of the protein structures responsible for metabolism: simple molecules that powered early life on Earth and serve as chemical signals that NASA could use to search for life on other planets.
Their study, which predicts what the earliest proteins looked like 3.5 billion to 2.5 billion years ago, is published in the journal Proceedings of the National Academy of Sciences.
The scientists retraced, like a many thousand piece puzzle, the evolution of enzymes (proteins) from the present to the deep past. The solution to the puzzle required two missing pieces, and life on Earth could not exist without them. By constructing a network connected by their roles in metabolism, this team discovered the missing pieces.
"We know very little about how life started on our planet. This work allowed us to glimpse deep in time and propose the earliest metabolic proteins," said co-author Vikas Nanda, a professor of Biochemistry and Molecular Biology at Rutgers Robert Wood Johnson Medical School and a resident faculty member at the Center for Advanced Biotechnology and Medicine. "Our predictions will be tested in the laboratory to better understand the origins of life on Earth and to inform how life may originate elsewhere. We are building models of proteins in the lab and testing whether they can trigger reactions critical for early metabolism."
A Rutgers-led team of scientists called ENIGMA (Evolution of Nanomachines in Geospheres and Microbial Ancestors) is conducting the research with a NASA grant and via membership in the NASA Astrobiology Program. The ENIGMA project seeks to reveal the role of the simplest proteins that catalyzed the earliest stages of life.
"We think life was built from very small building blocks and emerged like a Lego set to make cells and more complex organisms like us," said senior author Paul G. Falkowski, ENIGMA principal investigator and a distinguished professor at Rutgers University-New Brunswick who leads the Environmental Biophysics and Molecular Ecology Laboratory. "We think we have found the building blocks of life -- the Lego set that led, ultimately, to the evolution of cells, animals and plants."
The Rutgers team focused on two protein "folds" that are likely the first structures in early metabolism. They are a ferredoxin fold that binds iron-sulfur compounds, and a "Rossmann" fold, which binds nucleotides (the building blocks of DNA and RNA). These are two pieces of the puzzle that must fit in the evolution of life.
Proteins are chains of amino acids and a chain's 3D path in space is called a fold. Ferredoxins are metals found in modern proteins and shuttle electrons around cells to promote metabolism. Electrons flow through solids, liquids and gases and power living systems, and the same electrical force must be present in any other planetary system with a chance to support life.
There is evidence the two folds may have shared a common ancestor and, if true, the ancestor may have been the first metabolic enzyme of life.
Read more at Science Daily
Their study, which predicts what the earliest proteins looked like 3.5 billion to 2.5 billion years ago, is published in the journal Proceedings of the National Academy of Sciences.
The scientists retraced, like a many thousand piece puzzle, the evolution of enzymes (proteins) from the present to the deep past. The solution to the puzzle required two missing pieces, and life on Earth could not exist without them. By constructing a network connected by their roles in metabolism, this team discovered the missing pieces.
"We know very little about how life started on our planet. This work allowed us to glimpse deep in time and propose the earliest metabolic proteins," said co-author Vikas Nanda, a professor of Biochemistry and Molecular Biology at Rutgers Robert Wood Johnson Medical School and a resident faculty member at the Center for Advanced Biotechnology and Medicine. "Our predictions will be tested in the laboratory to better understand the origins of life on Earth and to inform how life may originate elsewhere. We are building models of proteins in the lab and testing whether they can trigger reactions critical for early metabolism."
A Rutgers-led team of scientists called ENIGMA (Evolution of Nanomachines in Geospheres and Microbial Ancestors) is conducting the research with a NASA grant and via membership in the NASA Astrobiology Program. The ENIGMA project seeks to reveal the role of the simplest proteins that catalyzed the earliest stages of life.
"We think life was built from very small building blocks and emerged like a Lego set to make cells and more complex organisms like us," said senior author Paul G. Falkowski, ENIGMA principal investigator and a distinguished professor at Rutgers University-New Brunswick who leads the Environmental Biophysics and Molecular Ecology Laboratory. "We think we have found the building blocks of life -- the Lego set that led, ultimately, to the evolution of cells, animals and plants."
The Rutgers team focused on two protein "folds" that are likely the first structures in early metabolism. They are a ferredoxin fold that binds iron-sulfur compounds, and a "Rossmann" fold, which binds nucleotides (the building blocks of DNA and RNA). These are two pieces of the puzzle that must fit in the evolution of life.
Proteins are chains of amino acids and a chain's 3D path in space is called a fold. Ferredoxins are metals found in modern proteins and shuttle electrons around cells to promote metabolism. Electrons flow through solids, liquids and gases and power living systems, and the same electrical force must be present in any other planetary system with a chance to support life.
There is evidence the two folds may have shared a common ancestor and, if true, the ancestor may have been the first metabolic enzyme of life.
Read more at Science Daily
Expanding universe: We may be in a vast bubble
The earth, solar system, entire Milky Way and the few thousand galaxies closest to us move in a vast "bubble" that is 250 million light years in diameter, where the average density of matter is half as large as for the rest of the universe. This is the hypothesis put forward by a theoretical physicist from the University of Geneva (UNIGE) to solve a conundrum that has been splitting the scientific community for a decade: at what speed is the universe expanding? Until now, at least two independent calculation methods have arrived at two values that are different by about 10% with a deviation that is statistically irreconcilable. This new approach, which is set out in the journal Physics Letters B, erases this divergence without making use of any "new physics."
The universe has been expanding since the Big Bang occurred 13.8 billion years ago -- a proposition first made by the Belgian canon and physicist Georges Lemaître (1894-1966), and first demonstrated by Edwin Hubble (1889-1953). The American astronomer discovered in 1929 that every galaxy is pulling away from us, and that the most distant galaxies are moving the most quickly. This suggests that there was a time in the past when all the galaxies were located at the same spot, a time that can only correspond to the Big Bang. This research gave rise to the Hubble-Lemaître law, including the Hubble constant (H0), which denotes the universe's rate of expansion. The best H0 estimates currently lie around 70 (km/s)/Mpc (meaning that the universe is expanding 70 kilometres a second more quickly every 3.26 million light years). The problem is that there are two conflicting methods of calculation.
Sporadic supernovae
The first is based on the cosmic microwave background: this is the microwave radiation that comes at us from everywhere, emitted at the time the universe became cold enough for light finally to be able to circulate freely (about 370,000 years after the Big Bang). Using the precise data supplied by the Planck space mission, and given the fact that the universe is homogeneous and isotropic, a value of 67.4 is obtained for H0 using Einstein's theory of general relativity to run through the scenario. The second calculation method is based on the supernovae which appear sporadically in distant galaxies. These very bright events provide the observer with highly precise distances, an approach that has made it possible to determine a value for H0 of 74.
Lucas Lombriser, a professor in the Theoretical Physics Department in UNIGE's Faculty of Sciences, explains: "These two values carried on becoming more precise for many years while remaining different from each other. It didn't take much to spark a scientific controversy and even to arouse the exciting hope that we were perhaps dealing with a 'new physics'." To narrow the gap, professor Lombriser entertained the idea that the universe is not as homogeneous as claimed, a hypothesis that may seem obvious on relatively modest scales. There is no doubt that matter is distributed differently inside a galaxy than outside one. It is more difficult, however, to imagine fluctuations in the average density of matter calculated on volumes thousands of times larger than a galaxy.
The "Hubble Bubble"
"If we were in a kind of gigantic 'bubble', continues professor Lombriser, where the density of matter was significantly lower than the known density for the entire universe, it would have consequences on the distances of supernovae and, ultimately, on determining H0."
Read more at Science Daily
The universe has been expanding since the Big Bang occurred 13.8 billion years ago -- a proposition first made by the Belgian canon and physicist Georges Lemaître (1894-1966), and first demonstrated by Edwin Hubble (1889-1953). The American astronomer discovered in 1929 that every galaxy is pulling away from us, and that the most distant galaxies are moving the most quickly. This suggests that there was a time in the past when all the galaxies were located at the same spot, a time that can only correspond to the Big Bang. This research gave rise to the Hubble-Lemaître law, including the Hubble constant (H0), which denotes the universe's rate of expansion. The best H0 estimates currently lie around 70 (km/s)/Mpc (meaning that the universe is expanding 70 kilometres a second more quickly every 3.26 million light years). The problem is that there are two conflicting methods of calculation.
Sporadic supernovae
The first is based on the cosmic microwave background: this is the microwave radiation that comes at us from everywhere, emitted at the time the universe became cold enough for light finally to be able to circulate freely (about 370,000 years after the Big Bang). Using the precise data supplied by the Planck space mission, and given the fact that the universe is homogeneous and isotropic, a value of 67.4 is obtained for H0 using Einstein's theory of general relativity to run through the scenario. The second calculation method is based on the supernovae which appear sporadically in distant galaxies. These very bright events provide the observer with highly precise distances, an approach that has made it possible to determine a value for H0 of 74.
Lucas Lombriser, a professor in the Theoretical Physics Department in UNIGE's Faculty of Sciences, explains: "These two values carried on becoming more precise for many years while remaining different from each other. It didn't take much to spark a scientific controversy and even to arouse the exciting hope that we were perhaps dealing with a 'new physics'." To narrow the gap, professor Lombriser entertained the idea that the universe is not as homogeneous as claimed, a hypothesis that may seem obvious on relatively modest scales. There is no doubt that matter is distributed differently inside a galaxy than outside one. It is more difficult, however, to imagine fluctuations in the average density of matter calculated on volumes thousands of times larger than a galaxy.
The "Hubble Bubble"
"If we were in a kind of gigantic 'bubble', continues professor Lombriser, where the density of matter was significantly lower than the known density for the entire universe, it would have consequences on the distances of supernovae and, ultimately, on determining H0."
Read more at Science Daily
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