The brains of people with excellent general knowledge are particularly efficiently wired. This was shown by neuroscientists at Ruhr-Universität Bochum and Humboldt-Universität zu Berlin using magnetic resonance imaging. "Although we can precisely measure the general knowledge of people and this wealth of knowledge is very important for an individual's journey through life, we currently know little about the links between general knowledge and the characteristics of the brain," says Dr. Erhan Genç from the Department of Biopsychology in Bochum. The team describes the results in the European Journal of Personality on 28 July 2019.
Brain images and knowledge test
The researchers examined the brains of 324 men and women with a special form of magnetic resonance imaging called diffusion tensor imaging. This makes it possible to reconstruct the pathways of nerve fibres and thus gain an insight into the structural network properties of the brain. By means of mathematical algorithms, the researchers assigned an individual value to the brain of each participant, which reflected the efficiency of his or her structural fibre network.
The participants also completed a general knowledge test called the Bochum Knowledge Test, which was developed in Bochum by Dr. Rüdiger Hossiep. It is comprised of over 300 questions from various fields of knowledge such as art and architecture or biology and chemistry. The team led by Erhan Genç finally investigated whether the efficiency of structural networking is associated with the amount of general knowledge stored.
The result: People with a very efficient fibre network had more general knowledge than those with less efficient structural networking.
Linking pieces of information
"We assume that individual units of knowledge are dispersed throughout the entire brain in the form of pieces of information," explains Erhan Genç. "Efficient networking of the brain is essential in order to put together the information stored in various areas of the brain and successfully recall knowledge content."
An example: To answer the question of which constants occur in Einstein's theory of relativity, you have to connect the meaning of the term "constant" with knowledge of the theory of relativity. "We assume that more efficient networking of the brain contributes to better integration of pieces of information and thus leads to better results in a general knowledge test," says the Bochum-based researcher.
From Science Daily
Jul 31, 2019
Call it Mighty Mouse: Breakthrough leaps Alzheimer's research hurdle
University of California, Irvine researchers have made it possible to learn how key human brain cells respond to Alzheimer's, vaulting a major obstacle in the quest to understand and one day vanquish it. By developing a way for human brain immune cells known as microglia to grow and function in mice, scientists now have an unprecedented view of crucial mechanisms contributing to the disease.
The team, led by Mathew Blurton-Jones, associate professor of neurobiology & behavior, said the breakthrough also holds promise for investigating many other neurological conditions such as Parkinson's, traumatic brain injury, and stroke. The details of their study have just been published in the journal Neuron.
The scientists dedicated four years to devising the new rodent model, which is considered "chimeric." The word, stemming from the mythical Greek monster Chimera that was part goat, lion and serpent, describes an organism containing at least two different sets of DNA.
To create the specialized mouse, the team generated induced pluripotent stem cells, or iPSCs, using cells donated by adult patients. Once created, iPSCs can be turned into any other type of cell. In this case, the researchers coaxed the iPSCs into becoming young microglia and implanted them into genetically-modified mice. Examining the rodents several months later, the scientists found about 80-percent of the microglia in their brains was human, opening the door for an array of new research.
"Microglia are now seen as having a crucial role in the development and progression of Alzheimer's," said Blurton-Jones. "The functions of our cells are influenced by which genes are turned on or off. Recent research has identified over 40 different genes with links to Alzheimer's and the majority of these are switched on in microglia. However, so far we've only been able to study human microglia at the end stage of Alzheimer's in post-mortem tissues or in petri dishes."
In verifying the chimeric model's effectiveness for these investigations, the team checked how its human microglia reacted to amyloid plaques, protein fragments in the brain that accumulate in people with Alzheimer's. They indeed imitated the expected response by migrating toward the amyloid plaques and surrounding them.
"The human microglia also showed significant genetic differences from the rodent version in their response to the plaques, demonstrating how important it is to study the human form of these cells," Blurton-Jones said.
"This specialized mouse will allow researchers to better mimic the human condition during different phases of Alzheimer's while performing properly-controlled experiments," said Jonathan Hasselmann, one of the two neurobiology & behavior graduate students involved in the study. Understanding the stages of the disease, which according to the Alzheimer's Association can last from two to 20 years, has been among the challenges facing researchers.
Read more at Science Daily
The team, led by Mathew Blurton-Jones, associate professor of neurobiology & behavior, said the breakthrough also holds promise for investigating many other neurological conditions such as Parkinson's, traumatic brain injury, and stroke. The details of their study have just been published in the journal Neuron.
The scientists dedicated four years to devising the new rodent model, which is considered "chimeric." The word, stemming from the mythical Greek monster Chimera that was part goat, lion and serpent, describes an organism containing at least two different sets of DNA.
To create the specialized mouse, the team generated induced pluripotent stem cells, or iPSCs, using cells donated by adult patients. Once created, iPSCs can be turned into any other type of cell. In this case, the researchers coaxed the iPSCs into becoming young microglia and implanted them into genetically-modified mice. Examining the rodents several months later, the scientists found about 80-percent of the microglia in their brains was human, opening the door for an array of new research.
"Microglia are now seen as having a crucial role in the development and progression of Alzheimer's," said Blurton-Jones. "The functions of our cells are influenced by which genes are turned on or off. Recent research has identified over 40 different genes with links to Alzheimer's and the majority of these are switched on in microglia. However, so far we've only been able to study human microglia at the end stage of Alzheimer's in post-mortem tissues or in petri dishes."
In verifying the chimeric model's effectiveness for these investigations, the team checked how its human microglia reacted to amyloid plaques, protein fragments in the brain that accumulate in people with Alzheimer's. They indeed imitated the expected response by migrating toward the amyloid plaques and surrounding them.
"The human microglia also showed significant genetic differences from the rodent version in their response to the plaques, demonstrating how important it is to study the human form of these cells," Blurton-Jones said.
"This specialized mouse will allow researchers to better mimic the human condition during different phases of Alzheimer's while performing properly-controlled experiments," said Jonathan Hasselmann, one of the two neurobiology & behavior graduate students involved in the study. Understanding the stages of the disease, which according to the Alzheimer's Association can last from two to 20 years, has been among the challenges facing researchers.
Read more at Science Daily
Jul 30, 2019
The moon is older than previously believed
A new study spearheaded by Earth scientists at the University of Cologne's Institute of Geology and Mineralogy has constrained the age of the Moon to approximately 50 million years after the formation of the solar system. After the formation of the solar system, 4.56 billion years ago, the Moon formed approximately 4.51 billion years ago. The new study has thus determined that the Moon is significantly older than previously believed -- earlier research had estimated the Moon to have formed approximately 150 million years after solar system's formation. To achieve these results, the scientists analysed the chemical composition of a diverse range of samples collected during the Apollo missions. The study 'Early Moon formation inferred from hafnium-tungsten systematics' was published in Nature Geoscience.
On 21 July 1969, humankind took its first steps on another celestial body. In their few hours on the lunar surface, the crew of Apollo 11 collected and brought back to Earth 21.55 kg of samples. Almost exactly 50 years later, these samples are still teaching us about key events of the early solar system and the history of the Earth-Moon system. Determining the age of the Moon is also important to understand how and at which time the Earth formed, and how it evolved at the very beginning of the solar system.
This study focuses on the chemical signatures of different types of lunar samples collected by the different Apollo missions. 'By comparing the relative amounts of different elements in rocks that formed at different times, it is possible to learn how each sample is related to the lunar interior and the solidification of the magma ocean,' says Dr Raúl Fonseca from the University of Cologne, who studies processes that occurred in the Moon's interior in laboratory experiments together with his colleague Dr Felipe Leitzke.
The Moon likely formed in the aftermath of a giant collision between a Mars-sized planetary body and the early Earth. Over time, the Moon accreted from the cloud of material blasted into Earth's orbit. The newborn Moon was covered in a magma ocean, which formed different types of rocks as it cooled. 'These rocks recorded information about the formation of the Moon, and can still be found today on the lunar surface,' says Dr Maxwell Thiemens, former University of Cologne researcher and lead author of the study. Dr Peter Sprung, co-author of the study, adds: 'Such observations are not possible on Earth anymore, as our planet has been geologically active over time. The Moon thus provides a unique opportunity to study planetary evolution.'
The Cologne scientists used the relationship between the rare elements hafnium, uranium and tungsten as a probe to understand the amount of melting that occurred to generate the mare basalts, i.e., the black regions on the lunar surface. Owing to an unprecedented measurement precision, the study could identify distinct trends amongst the different suites of rocks, which now allows for a better understanding of the behaviour of these key rare elements.
Studying hafnium and tungsten on the Moon are particularly important because they constitute a natural radioactive clock of the isotope hafnium-182 decaying into tungsten-182. This radioactive decay only lasted for the first 70 million years of the solar system. By combining the hafnium and tungsten information measured in the Apollo samples with information from laboratory experiments, the study finds that the Moon already started solidifying as early as 50 million years after solar system formed. 'This age information means that any giant impact had to occur before that time, which answers a fiercely debated question amongst the scientific community regarding when the Moon formed,' adds Professor Dr Carsten Münker from the UoC's Institute of Geology and Mineralogy, senior author of the study.
Read more at Science Daily
On 21 July 1969, humankind took its first steps on another celestial body. In their few hours on the lunar surface, the crew of Apollo 11 collected and brought back to Earth 21.55 kg of samples. Almost exactly 50 years later, these samples are still teaching us about key events of the early solar system and the history of the Earth-Moon system. Determining the age of the Moon is also important to understand how and at which time the Earth formed, and how it evolved at the very beginning of the solar system.
This study focuses on the chemical signatures of different types of lunar samples collected by the different Apollo missions. 'By comparing the relative amounts of different elements in rocks that formed at different times, it is possible to learn how each sample is related to the lunar interior and the solidification of the magma ocean,' says Dr Raúl Fonseca from the University of Cologne, who studies processes that occurred in the Moon's interior in laboratory experiments together with his colleague Dr Felipe Leitzke.
The Moon likely formed in the aftermath of a giant collision between a Mars-sized planetary body and the early Earth. Over time, the Moon accreted from the cloud of material blasted into Earth's orbit. The newborn Moon was covered in a magma ocean, which formed different types of rocks as it cooled. 'These rocks recorded information about the formation of the Moon, and can still be found today on the lunar surface,' says Dr Maxwell Thiemens, former University of Cologne researcher and lead author of the study. Dr Peter Sprung, co-author of the study, adds: 'Such observations are not possible on Earth anymore, as our planet has been geologically active over time. The Moon thus provides a unique opportunity to study planetary evolution.'
The Cologne scientists used the relationship between the rare elements hafnium, uranium and tungsten as a probe to understand the amount of melting that occurred to generate the mare basalts, i.e., the black regions on the lunar surface. Owing to an unprecedented measurement precision, the study could identify distinct trends amongst the different suites of rocks, which now allows for a better understanding of the behaviour of these key rare elements.
Studying hafnium and tungsten on the Moon are particularly important because they constitute a natural radioactive clock of the isotope hafnium-182 decaying into tungsten-182. This radioactive decay only lasted for the first 70 million years of the solar system. By combining the hafnium and tungsten information measured in the Apollo samples with information from laboratory experiments, the study finds that the Moon already started solidifying as early as 50 million years after solar system formed. 'This age information means that any giant impact had to occur before that time, which answers a fiercely debated question amongst the scientific community regarding when the Moon formed,' adds Professor Dr Carsten Münker from the UoC's Institute of Geology and Mineralogy, senior author of the study.
Read more at Science Daily
At the edge of chaos: New method for exoplanet stability analysis
Exoplanets revolving around distant stars are coming quickly into focus with advanced technology like the Kepler space telescope. Gaining a full understanding of those systems is difficult, because the initial positions and velocities of the exoplanets are unknown. Determining whether the system dynamics are quasi-periodic or chaotic is cumbersome, expensive and computationally demanding.
In this week's Chaos, from AIP Publishing, Tamás Kovács delivers an alternative method for stability analysis of exoplanetary bodies using only the observed time series data to deduce dynamical measurements and quantify the unpredictability of exoplanet systems.
"If we don't know the governing equations of the motion of a system, and we only have the time series -- what we measure with the telescope -- then we want to transform that time series into a complex network. In this case, it is called a recurrence network," Kovács said. "This network holds all of the dynamical features of the underlying system we want to analyze."
The paper draws on the work of physicist Floris Takens, who proposed in 1981 that the dynamics of a system could be reconstructed using a series of observations about the state of the system. With Takens' embedding theorem as a starting point, Kovács uses time delay embedding to reconstruct a high-dimensional trajectory and then identify recurrence points, where bodies in the phase space are close to each other.
"Those special points will be the vertices and the edges of the complex network," Kovács said. "Once you have the network, you can reprogram this network to be able to apply measures like transitivity, average path length or others unique to that network."
Kovács tests the reliability of the method using a known system as a model, the three-body system of Saturn, Jupiter and the sun, and then applies it to the Kepler 36b and 36c system. His Kepler system results agree with what is known.
"Earlier studies pointed out that Kepler 36b and 36c is a very special system, because from the direct simulation and the numerical integrations, we see the system is at the edge of the chaos," Kovács said. "Sometimes, it shows regular dynamics, and at other times, it seems to be chaotic."
Read more at Science Daily
In this week's Chaos, from AIP Publishing, Tamás Kovács delivers an alternative method for stability analysis of exoplanetary bodies using only the observed time series data to deduce dynamical measurements and quantify the unpredictability of exoplanet systems.
"If we don't know the governing equations of the motion of a system, and we only have the time series -- what we measure with the telescope -- then we want to transform that time series into a complex network. In this case, it is called a recurrence network," Kovács said. "This network holds all of the dynamical features of the underlying system we want to analyze."
The paper draws on the work of physicist Floris Takens, who proposed in 1981 that the dynamics of a system could be reconstructed using a series of observations about the state of the system. With Takens' embedding theorem as a starting point, Kovács uses time delay embedding to reconstruct a high-dimensional trajectory and then identify recurrence points, where bodies in the phase space are close to each other.
"Those special points will be the vertices and the edges of the complex network," Kovács said. "Once you have the network, you can reprogram this network to be able to apply measures like transitivity, average path length or others unique to that network."
Kovács tests the reliability of the method using a known system as a model, the three-body system of Saturn, Jupiter and the sun, and then applies it to the Kepler 36b and 36c system. His Kepler system results agree with what is known.
"Earlier studies pointed out that Kepler 36b and 36c is a very special system, because from the direct simulation and the numerical integrations, we see the system is at the edge of the chaos," Kovács said. "Sometimes, it shows regular dynamics, and at other times, it seems to be chaotic."
Read more at Science Daily
Individuals with obesity get more satisfaction from their food
The propensity to overeat may, in part, be a function of the satisfaction derived from eating. A new study in the Journal of the Academy of Nutrition and Dietetics, published by Elsevier, found no significant difference in taste perceptions between participants of normal weight and those who were overweight. However, participants with obesity had initial taste perceptions that were greater than participants who were not obese, which declined at a more gradual rate than participants who were not obese. This quantification of satisfaction from food may help explain why some people eat more than others.
"Obesity is a major public-health problem. Thirty percent of the US population is obese, and obesity-related health problems (diabetes, hypertension, etc.) are increasing. Causes of obesity are varied, but food consumption decisions play an important role, especially decisions about what foods to eat and how much to consume. Taste perceptions may lead to overeating. If people with obesity have different taste perceptions than nonobese people, it could lead to better understanding of obesity and possibly designing new approaches to prevent obesity," explained lead investigator Linnea A. Polgreen, PhD, Department of Pharmacy Practice and Science, University of Iowa, Iowa City, IA, USA.
As individuals consume more of a food item, they experience diminishing marginal taste perception, which means their level of perceived taste from additional consumption may tend to decline (ie, additional consumption may become less pleasurable). The relationship between perceived taste and quantity consumed has traditionally been referred to as sensory-specific satiety.
In order to determine if marginal taste perceptions differ among participants of normal-weight, those who are overweight and those with obesity, and whether knowledge of nutritional information affects marginal taste perception, researchers at the University of Iowa conducted a non-clinical, randomized controlled trial of 290 adults (161 with normal BMI, 78 considered overweight, and 51 considered obese) to measure instantaneous taste perceptions. Eighty percent of the participants were female, and ages ranged from 18 to 75 years. Participants were offered and rated one piece of chocolate at a time in a controlled environment and could eat as much as they wanted without feeling uncomfortable. They consumed between two and 51 pieces. Half of the study participants received nutritional information about the chocolate before the chocolate tasting began.
The study identified a consistent association between taste from food, specifically chocolate, and BMI by directly observing instantaneous taste changes over a period of time, rather than just at the beginning and end of a period of consumption, as in prior studies.
Typically, the appeal of a specific food may decline as more of that food is eaten: the first bite of chocolate is better than the 10th, a phenomenon consistent with the concept of sensory-specific satiety. As anticipated, researchers found that ratings generally went down after each piece of chocolate consumed with no significant difference in taste perceptions between normal and overweight participants reported. However, participants with obesity had higher levels of initial taste perception, rated subsequent pieces higher than their counterparts without obesity, and their ratings declined at a more gradual rate compared to participants with normal weight and those with obesity. People hungrier prior to the study had greater taste perception; women's taste perceptions declined faster than men's; and providing nutritional information prior to chocolate consumption did not affect taste perception.
"In our study population, people with obesity reported a higher level of satisfaction for each additional piece of chocolate compared to nonobese people. Thus, their taste preferences appear markedly different," noted co-investigator Aaron C. Miller, PhD, Department of Epidemiology, University of Iowa, Iowa City, IA, USA. "Our findings further indicate that obese participants needed to consume a greater quantity of chocolate than nonobese participants to experience a similar decline in taste perceptions. Specifically, obese women needed to eat 12.5 pieces of chocolate to fall to the same level of taste perception as nonobese women who ate only 10 pieces, which corresponds to a difference of 67.5 calories. This may, in part, explain why obese people consume more than nonobese people."
Read more at Science Daily
"Obesity is a major public-health problem. Thirty percent of the US population is obese, and obesity-related health problems (diabetes, hypertension, etc.) are increasing. Causes of obesity are varied, but food consumption decisions play an important role, especially decisions about what foods to eat and how much to consume. Taste perceptions may lead to overeating. If people with obesity have different taste perceptions than nonobese people, it could lead to better understanding of obesity and possibly designing new approaches to prevent obesity," explained lead investigator Linnea A. Polgreen, PhD, Department of Pharmacy Practice and Science, University of Iowa, Iowa City, IA, USA.
As individuals consume more of a food item, they experience diminishing marginal taste perception, which means their level of perceived taste from additional consumption may tend to decline (ie, additional consumption may become less pleasurable). The relationship between perceived taste and quantity consumed has traditionally been referred to as sensory-specific satiety.
In order to determine if marginal taste perceptions differ among participants of normal-weight, those who are overweight and those with obesity, and whether knowledge of nutritional information affects marginal taste perception, researchers at the University of Iowa conducted a non-clinical, randomized controlled trial of 290 adults (161 with normal BMI, 78 considered overweight, and 51 considered obese) to measure instantaneous taste perceptions. Eighty percent of the participants were female, and ages ranged from 18 to 75 years. Participants were offered and rated one piece of chocolate at a time in a controlled environment and could eat as much as they wanted without feeling uncomfortable. They consumed between two and 51 pieces. Half of the study participants received nutritional information about the chocolate before the chocolate tasting began.
The study identified a consistent association between taste from food, specifically chocolate, and BMI by directly observing instantaneous taste changes over a period of time, rather than just at the beginning and end of a period of consumption, as in prior studies.
Typically, the appeal of a specific food may decline as more of that food is eaten: the first bite of chocolate is better than the 10th, a phenomenon consistent with the concept of sensory-specific satiety. As anticipated, researchers found that ratings generally went down after each piece of chocolate consumed with no significant difference in taste perceptions between normal and overweight participants reported. However, participants with obesity had higher levels of initial taste perception, rated subsequent pieces higher than their counterparts without obesity, and their ratings declined at a more gradual rate compared to participants with normal weight and those with obesity. People hungrier prior to the study had greater taste perception; women's taste perceptions declined faster than men's; and providing nutritional information prior to chocolate consumption did not affect taste perception.
"In our study population, people with obesity reported a higher level of satisfaction for each additional piece of chocolate compared to nonobese people. Thus, their taste preferences appear markedly different," noted co-investigator Aaron C. Miller, PhD, Department of Epidemiology, University of Iowa, Iowa City, IA, USA. "Our findings further indicate that obese participants needed to consume a greater quantity of chocolate than nonobese participants to experience a similar decline in taste perceptions. Specifically, obese women needed to eat 12.5 pieces of chocolate to fall to the same level of taste perception as nonobese women who ate only 10 pieces, which corresponds to a difference of 67.5 calories. This may, in part, explain why obese people consume more than nonobese people."
Read more at Science Daily
Tech companies not doing enough to protect users from phishing scams
Technology companies could be doing much more to protect individuals and organisations from the threats posed by phishing, according to research by the University of Plymouth.
However, users also need to make themselves more aware of the dangers to ensure potential scammers do not obtain access to personal or sensitive information.
Academics from Plymouth's Centre for Security, Communications and Network (CSCAN) Research assessed the effectiveness of phishing filters employed by various email service providers.
They sent two sets of messages to victim accounts, using email content obtained from archives of reported phishing attacks, with the first as plain text with links removed and the second having links retained and pointing to their original destination.
They then examined which mailbox it reached within email accounts as well as whether they were explicitly labelled in any way to denote them as suspicious or malicious.
In the significant majority of cases (75% without links and 64% with links) the potential phishing messages made it into inboxes and were not in any way labelled to highlight them as spam or suspicious. Moreover, only 6% of messages were explicitly labelled as malicious.
Professor Steven Furnell, leader of CSCAN, worked on the study with MSc student Kieran Millet and Associate Professor of Cyber Security Dr Maria Papadaki.
He said: "The poor performance of most providers implies they either do not employ filtering based on language content, or that it is inadequate to protect users. Given users' tendency to perform poorly at identifying malicious messages this is a worrying outcome. The results suggest an opportunity to improve phishing detection in general, but the technology as it stands cannot be relied upon to provide anything other than a small contribution in this context."
The number of phishing incidents has risen dramatically since they were first recorded in 2003. In fact, global software giant Kaspersky Lab reported that its anti-phishing system was triggered 482,465,211 times in 2018, almost double the number for 2017.
It is also a significant problem for businesses, with 80% telling the Cyber Security Breaches Survey 2019 that they have encountered 'Fraudulent emails or being directed to fraudulent websites' -- placing this category well ahead of malware and ransomware.
Phishing is designed to trick victims into divulging sensitive information, such as identity and financial-related data, and the threat can actually take several forms:
However, users also need to make themselves more aware of the dangers to ensure potential scammers do not obtain access to personal or sensitive information.
Academics from Plymouth's Centre for Security, Communications and Network (CSCAN) Research assessed the effectiveness of phishing filters employed by various email service providers.
They sent two sets of messages to victim accounts, using email content obtained from archives of reported phishing attacks, with the first as plain text with links removed and the second having links retained and pointing to their original destination.
They then examined which mailbox it reached within email accounts as well as whether they were explicitly labelled in any way to denote them as suspicious or malicious.
In the significant majority of cases (75% without links and 64% with links) the potential phishing messages made it into inboxes and were not in any way labelled to highlight them as spam or suspicious. Moreover, only 6% of messages were explicitly labelled as malicious.
Professor Steven Furnell, leader of CSCAN, worked on the study with MSc student Kieran Millet and Associate Professor of Cyber Security Dr Maria Papadaki.
He said: "The poor performance of most providers implies they either do not employ filtering based on language content, or that it is inadequate to protect users. Given users' tendency to perform poorly at identifying malicious messages this is a worrying outcome. The results suggest an opportunity to improve phishing detection in general, but the technology as it stands cannot be relied upon to provide anything other than a small contribution in this context."
The number of phishing incidents has risen dramatically since they were first recorded in 2003. In fact, global software giant Kaspersky Lab reported that its anti-phishing system was triggered 482,465,211 times in 2018, almost double the number for 2017.
It is also a significant problem for businesses, with 80% telling the Cyber Security Breaches Survey 2019 that they have encountered 'Fraudulent emails or being directed to fraudulent websites' -- placing this category well ahead of malware and ransomware.
Phishing is designed to trick victims into divulging sensitive information, such as identity and financial-related data, and the threat can actually take several forms:
- Bulk-phishing -- where the approach is not specially targeted or tailored toward the recipient;
- Spear-phishing -- where the message is targeted at specific individuals or companies and tailored accordingly;
- Clone-phishing -- where the scammers take a legitimate email containing an attachment or link, and replace it with a malicious version;
- Whaling -- in these cases the phishing is specifically targeted towards high value or senior individuals.
Jul 29, 2019
Origin of life: The importance of interfaces
Tiny gas-filled bubbles in the porous rock found around hot springs are thought to have played an important role in the origin of life. Temperature differences at the interface between liquid phases could therefore have initiated prebiotic chemical evolution.
A plethora of physicochemical processes must have created the conditions that enabled living systems to emerge on the early Earth. In other words, the era of biological evolution must have been preceded by a -- presumably protracted -- phase of 'prebiotic' chemical evolution, during which the first informational molecules capable of replicating themselves were assembled and selected. This scenario immediately raises another question: Under what environmental conditions could prebiotic evolution have taken place? One possible setting has long been discussed and explored -- tiny pores in volcanic rocks. An international team of researchers led by Dieter Braun (Professor of Systems Biophysics at Ludwig-Maximilians-Universitaet (LMU) in Munich) has now taken a closer look at the water-air interfaces in these pores. They form spontaneously at gas-filled bubbles and show an interesting combination of effects.
They found that they could have played an important part in facilitating the physicochemical interactions that contributed to the origin of life. Specifically, Braun and his colleagues asked whether such interfaces could have stimulated the kinds of chemical reactions that triggered the initial stages of prebiotic chemical evolution. Their findings appear in the leading journal Nature Chemistry.
The study strongly supports the notion that tiny gas-filled bubbles that were trapped in, and reacted with, the surfaces of pores in volcanic rocks could indeed have accelerated the formation of the chemical networks that ultimately gave rise to the first cells. Thus, the authors were able to experimentally verify and characterize the facilitating effects of air-water interfaces on the relevant chemical reactions. If there is a difference in temperature along the surface of such a bubble, water will tend to evaporate on the warmer side and condense on the cooler side, just as a raindrop that lands on a window runs down the flat surface of the glass and eventually evaporates. "In principle, this process can be repeated ad infinitum, since the water continuously cycles between the gaseous and the liquid phase," says Braun, who has characterized the mechanism and the underlying physical processes in detail, together with his doctoral student Matthias Morasch and other members of his research group. The upshot of this cyclical phenomenon is that molecules accumulate to very high concentrations on the warmer side of the bubble.
"We began by making a series of measurements of reaction rates under various conditions, in order to characterize the nature of the underlying mechanism," says Morasch. The phenomenon turned out to be surprisingly effect and robust. Even small molecules could be concentrated to high levels. "We then tested a whole range of physical and chemical processes, which must have played a central role in the origin of life -- and all of them were markedly accelerated or made possible at all under the conditions prevailing at the air-water interface." The study benefitted from interactions between Braun's group of biophysicists and the specialists in disciplines such as chemistry and geology who work together with him in the Collaborative Research Centre (SFB/TRR) on the Origin of Life (which is funded by the DFG), and from cooperations with members of international teams.
For example, the LMU researchers show that physicochemical processes which promote the formation of polymers are either stimulated -- or made possible in the first place -- by the availability of an interface between the aqueous environment and the gas phase, which markedly enhances rates of chemical reactions and catalytic mechanisms. In fact, in such experiments, molecules could be accumulated to high concentrations within lipid membranes when the researchers added the appropriate chemical constituents. "The vesicles produced in this way are not perfect. But the finding nevertheless suggests how the first rudimentary protocells and their outer membranes might have been formed," says Morasch.
Read more at Science Daily
A plethora of physicochemical processes must have created the conditions that enabled living systems to emerge on the early Earth. In other words, the era of biological evolution must have been preceded by a -- presumably protracted -- phase of 'prebiotic' chemical evolution, during which the first informational molecules capable of replicating themselves were assembled and selected. This scenario immediately raises another question: Under what environmental conditions could prebiotic evolution have taken place? One possible setting has long been discussed and explored -- tiny pores in volcanic rocks. An international team of researchers led by Dieter Braun (Professor of Systems Biophysics at Ludwig-Maximilians-Universitaet (LMU) in Munich) has now taken a closer look at the water-air interfaces in these pores. They form spontaneously at gas-filled bubbles and show an interesting combination of effects.
They found that they could have played an important part in facilitating the physicochemical interactions that contributed to the origin of life. Specifically, Braun and his colleagues asked whether such interfaces could have stimulated the kinds of chemical reactions that triggered the initial stages of prebiotic chemical evolution. Their findings appear in the leading journal Nature Chemistry.
The study strongly supports the notion that tiny gas-filled bubbles that were trapped in, and reacted with, the surfaces of pores in volcanic rocks could indeed have accelerated the formation of the chemical networks that ultimately gave rise to the first cells. Thus, the authors were able to experimentally verify and characterize the facilitating effects of air-water interfaces on the relevant chemical reactions. If there is a difference in temperature along the surface of such a bubble, water will tend to evaporate on the warmer side and condense on the cooler side, just as a raindrop that lands on a window runs down the flat surface of the glass and eventually evaporates. "In principle, this process can be repeated ad infinitum, since the water continuously cycles between the gaseous and the liquid phase," says Braun, who has characterized the mechanism and the underlying physical processes in detail, together with his doctoral student Matthias Morasch and other members of his research group. The upshot of this cyclical phenomenon is that molecules accumulate to very high concentrations on the warmer side of the bubble.
"We began by making a series of measurements of reaction rates under various conditions, in order to characterize the nature of the underlying mechanism," says Morasch. The phenomenon turned out to be surprisingly effect and robust. Even small molecules could be concentrated to high levels. "We then tested a whole range of physical and chemical processes, which must have played a central role in the origin of life -- and all of them were markedly accelerated or made possible at all under the conditions prevailing at the air-water interface." The study benefitted from interactions between Braun's group of biophysicists and the specialists in disciplines such as chemistry and geology who work together with him in the Collaborative Research Centre (SFB/TRR) on the Origin of Life (which is funded by the DFG), and from cooperations with members of international teams.
For example, the LMU researchers show that physicochemical processes which promote the formation of polymers are either stimulated -- or made possible in the first place -- by the availability of an interface between the aqueous environment and the gas phase, which markedly enhances rates of chemical reactions and catalytic mechanisms. In fact, in such experiments, molecules could be accumulated to high concentrations within lipid membranes when the researchers added the appropriate chemical constituents. "The vesicles produced in this way are not perfect. But the finding nevertheless suggests how the first rudimentary protocells and their outer membranes might have been formed," says Morasch.
Read more at Science Daily
Sun's solar wind and plasma 'burps' created on Earth
The sun's solar wind affects nearly everything in the solar system. It can disrupt the function of Earth's satellites and creates the lights of the auroras.
A new study by University of Wisconsin-Madison physicists mimicked solar winds in the lab, confirming how they develop and providing an Earth-bound model for the future study of solar physics.
Our sun is essentially a big ball of hot plasma -- an energetic state of matter made up of ionized gas. As the sun spins, the plasma spins along, too. This plasma movement in the core of the sun produces a magnetic field that fills the solar atmosphere. At some distance from the sun's surface, known as the Alfvén surface, this magnetic field weakens and plasma breaks away from the sun, creating the solar wind.
"The solar wind is highly variable, but there are essentially two types: fast and slow," explains Ethan Peterson, a graduate student in the department of physics at UW-Madison and lead author of the study published online July 29 in Nature Physics. "Satellite missions have documented pretty well where the fast wind comes from, so we were trying to study specifically how the slow solar wind is generated and how it evolves as it travels toward Earth."
Peterson and his colleagues, including physics professor Cary Forest, may not have direct access to the big plasma ball of the sun, but they do have access to the next best thing: the Big Red Ball.
The Big Red Ball is a three-meter-wide hollow sphere, with a strong magnet at its center and various probes inside. The researchers pump helium gas in, ionize it to create a plasma, and then apply an electric current that, along with the magnetic field, stirs the plasma, creating a near-perfect mimic of the spinning plasma and electromagnetic fields of the sun.
With their mini-sun in place, the researchers can take measurements at many points inside the ball, allowing them to study solar phenomena in three dimensions.
First, they were able to recreate the Parker Spiral, a magnetic field that fills the entire solar system named for the scientist who first described the solar wind. Below the Alfvén surface, the magnetic field radiates straight out from the Sun. But at that surface, solar wind dynamics take over, dragging the magnetic field into a spiral.
"Satellite measurements are pretty consistent with the Parker Spiral model, but only at one point at a time, so you'd never be able to make a simultaneous, large-scale map of it like we can in the lab." Peterson says. "Our experimental measurements confirm Parker's theory of how it is created by these plasma flows."
The researchers were also able to identify the source of the Sun's plasma "burps," small, periodic ejections of plasma that fuel the slow solar wind. With the plasma spinning, they probed the magnetic field and the speed of the plasma. Their data mapped a region where the plasma was moving fast enough and the magnetic field was weak enough that the plasma could break off and eject radially.
"These ejections are observed by satellites, but no one knows what drives them," Peterson says. "We ended up seeing very similar burps in our experiment, and identified how they develop."
The researchers stress that their Earth-bound experiments complement, but don't replace, satellite missions. For example, the Parker Solar Probe, launched in August 2018, is expected to reach and even dip below the Alfvén surface. It will provide direct measurements of solar wind never obtained before.
"Our work shows that laboratory experiments can also get at the fundamental physics of these processes," Peterson says. "And because the Big Red Ball is now funded as a National User Facility, it says to the science community: If you want to study the physics of solar wind, you can do that here."
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A new study by University of Wisconsin-Madison physicists mimicked solar winds in the lab, confirming how they develop and providing an Earth-bound model for the future study of solar physics.
Our sun is essentially a big ball of hot plasma -- an energetic state of matter made up of ionized gas. As the sun spins, the plasma spins along, too. This plasma movement in the core of the sun produces a magnetic field that fills the solar atmosphere. At some distance from the sun's surface, known as the Alfvén surface, this magnetic field weakens and plasma breaks away from the sun, creating the solar wind.
"The solar wind is highly variable, but there are essentially two types: fast and slow," explains Ethan Peterson, a graduate student in the department of physics at UW-Madison and lead author of the study published online July 29 in Nature Physics. "Satellite missions have documented pretty well where the fast wind comes from, so we were trying to study specifically how the slow solar wind is generated and how it evolves as it travels toward Earth."
Peterson and his colleagues, including physics professor Cary Forest, may not have direct access to the big plasma ball of the sun, but they do have access to the next best thing: the Big Red Ball.
The Big Red Ball is a three-meter-wide hollow sphere, with a strong magnet at its center and various probes inside. The researchers pump helium gas in, ionize it to create a plasma, and then apply an electric current that, along with the magnetic field, stirs the plasma, creating a near-perfect mimic of the spinning plasma and electromagnetic fields of the sun.
With their mini-sun in place, the researchers can take measurements at many points inside the ball, allowing them to study solar phenomena in three dimensions.
First, they were able to recreate the Parker Spiral, a magnetic field that fills the entire solar system named for the scientist who first described the solar wind. Below the Alfvén surface, the magnetic field radiates straight out from the Sun. But at that surface, solar wind dynamics take over, dragging the magnetic field into a spiral.
"Satellite measurements are pretty consistent with the Parker Spiral model, but only at one point at a time, so you'd never be able to make a simultaneous, large-scale map of it like we can in the lab." Peterson says. "Our experimental measurements confirm Parker's theory of how it is created by these plasma flows."
The researchers were also able to identify the source of the Sun's plasma "burps," small, periodic ejections of plasma that fuel the slow solar wind. With the plasma spinning, they probed the magnetic field and the speed of the plasma. Their data mapped a region where the plasma was moving fast enough and the magnetic field was weak enough that the plasma could break off and eject radially.
"These ejections are observed by satellites, but no one knows what drives them," Peterson says. "We ended up seeing very similar burps in our experiment, and identified how they develop."
The researchers stress that their Earth-bound experiments complement, but don't replace, satellite missions. For example, the Parker Solar Probe, launched in August 2018, is expected to reach and even dip below the Alfvén surface. It will provide direct measurements of solar wind never obtained before.
"Our work shows that laboratory experiments can also get at the fundamental physics of these processes," Peterson says. "And because the Big Red Ball is now funded as a National User Facility, it says to the science community: If you want to study the physics of solar wind, you can do that here."
Read more at Science Daily
Camera can watch moving objects around corners
David Lindell, a graduate student in electrical engineering at Stanford University, donned a high visibility tracksuit and got to work, stretching, pacing and hopping across an empty room. Through a camera aimed away from Lindell -- at what appeared to be a blank wall -- his colleagues could watch his every move.
That's because, hidden to the naked eye, he was being scanned by a high powered laser and the single particles of light he reflected onto the walls around him were captured and reconstructed by the camera's advanced sensors and processing algorithm.
"People talk about building a camera that can see as well as humans for applications such as autonomous cars and robots, but we want to build systems that go well beyond that," said Gordon Wetzstein, an assistant professor of electrical engineering at Stanford. "We want to see things in 3D, around corners and beyond the visible light spectrum."
The camera system Lindell tested, which the researchers are presenting at the SIGGRAPH 2019 conference Aug. 1, builds upon previous around-the-corner cameras this team developed. It's able to capture more light from a greater variety of surfaces, see wider and farther away and is fast enough to monitor out-of-sight movement -- such as Lindell's calisthenics -- for the first time. Someday, the researchers hope superhuman vision systems could help autonomous cars and robots operate even more safely than they would with human guidance.
Practicality and seismology
Keeping their system practical is a high priority for these researchers. The hardware they chose, the scanning and image processing speeds, and the style of imaging are already common in autonomous car vision systems. Previous systems for viewing scenes outside a camera's line of sight relied on objects that either reflect light evenly or strongly. But real-world objects, including shiny cars, fall outside these categories, so this system can handle light bouncing off a range of surfaces, including disco balls, books and intricately textured statues.
Central to their advance was a laser 10,000 times more powerful than what they were using a year ago. The laser scans a wall opposite the scene of interest and that light bounces off the wall, hits the objects in the scene, bounces back to the wall and to the camera sensors. By the time the laser light reaches the camera only specks remain, but the sensor captures every one, sending it along to a highly efficient algorithm, also developed by this team, that untangles these echoes of light to decipher the hidden tableau.
"When you're watching the laser scanning it out, you don't see anything," described Lindell. "With this hardware, we can basically slow down time and reveal these tracks of light. It almost looks like magic."
The system can scan at four frames per second. It can reconstruct a scene at speeds of 60 frames per second on a computer with a graphics processing unit, which enhances graphics processing capabilities.
To advance their algorithm, the team looked to other fields for inspiration. The researchers were particularly drawn to seismic imaging systems -- which bounce sound waves off underground layers of Earth to learn what's beneath the surface -- and reconfigured their algorithm to likewise interpret bouncing light as waves emanating from the hidden objects. The result was the same high-speed and low memory usage with improvements in their abilities to see large scenes containing various materials.
"There are many ideas being used in other spaces -- seismology, imaging with satellites, synthetic aperture radar -- that are applicable to looking around corners," said Matthew O'Toole, an assistant professor at Carnegie Mellon University who was previously a postdoctoral fellow in Wetzstein's lab. "We're trying to take a little bit from these fields and we'll hopefully be able to give something back to them at some point."
Humble steps
Being able to see real-time movement from otherwise invisible light bounced around a corner was a thrilling moment for this team but a practical system for autonomous cars or robots will require further enhancements.
"It's very humble steps. The movement still looks low-resolution and it's not super-fast but compared to the state-of-the-art last year it is a significant improvement," said Wetzstein. "We were blown away the first time we saw these results because we've captured data that nobody's seen before."
Read more at Science Daily
That's because, hidden to the naked eye, he was being scanned by a high powered laser and the single particles of light he reflected onto the walls around him were captured and reconstructed by the camera's advanced sensors and processing algorithm.
"People talk about building a camera that can see as well as humans for applications such as autonomous cars and robots, but we want to build systems that go well beyond that," said Gordon Wetzstein, an assistant professor of electrical engineering at Stanford. "We want to see things in 3D, around corners and beyond the visible light spectrum."
The camera system Lindell tested, which the researchers are presenting at the SIGGRAPH 2019 conference Aug. 1, builds upon previous around-the-corner cameras this team developed. It's able to capture more light from a greater variety of surfaces, see wider and farther away and is fast enough to monitor out-of-sight movement -- such as Lindell's calisthenics -- for the first time. Someday, the researchers hope superhuman vision systems could help autonomous cars and robots operate even more safely than they would with human guidance.
Practicality and seismology
Keeping their system practical is a high priority for these researchers. The hardware they chose, the scanning and image processing speeds, and the style of imaging are already common in autonomous car vision systems. Previous systems for viewing scenes outside a camera's line of sight relied on objects that either reflect light evenly or strongly. But real-world objects, including shiny cars, fall outside these categories, so this system can handle light bouncing off a range of surfaces, including disco balls, books and intricately textured statues.
Central to their advance was a laser 10,000 times more powerful than what they were using a year ago. The laser scans a wall opposite the scene of interest and that light bounces off the wall, hits the objects in the scene, bounces back to the wall and to the camera sensors. By the time the laser light reaches the camera only specks remain, but the sensor captures every one, sending it along to a highly efficient algorithm, also developed by this team, that untangles these echoes of light to decipher the hidden tableau.
"When you're watching the laser scanning it out, you don't see anything," described Lindell. "With this hardware, we can basically slow down time and reveal these tracks of light. It almost looks like magic."
The system can scan at four frames per second. It can reconstruct a scene at speeds of 60 frames per second on a computer with a graphics processing unit, which enhances graphics processing capabilities.
To advance their algorithm, the team looked to other fields for inspiration. The researchers were particularly drawn to seismic imaging systems -- which bounce sound waves off underground layers of Earth to learn what's beneath the surface -- and reconfigured their algorithm to likewise interpret bouncing light as waves emanating from the hidden objects. The result was the same high-speed and low memory usage with improvements in their abilities to see large scenes containing various materials.
"There are many ideas being used in other spaces -- seismology, imaging with satellites, synthetic aperture radar -- that are applicable to looking around corners," said Matthew O'Toole, an assistant professor at Carnegie Mellon University who was previously a postdoctoral fellow in Wetzstein's lab. "We're trying to take a little bit from these fields and we'll hopefully be able to give something back to them at some point."
Humble steps
Being able to see real-time movement from otherwise invisible light bounced around a corner was a thrilling moment for this team but a practical system for autonomous cars or robots will require further enhancements.
"It's very humble steps. The movement still looks low-resolution and it's not super-fast but compared to the state-of-the-art last year it is a significant improvement," said Wetzstein. "We were blown away the first time we saw these results because we've captured data that nobody's seen before."
Read more at Science Daily
Elephant extinction will raise carbon dioxide levels in atmosphere
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| Forest elephants, Central African Republic |
In a paper recently published in Nature Geoscience, a Saint Louis University biologist and his colleagues found that elephant populations in central African forests encourage the growth of slow-growing trees with high wood density that sequester more carbon from the atmosphere than fast growing species which are the preferred foods of elephants.
As forest elephants preferentially browse on the fast growing species, they cause high levels of damage and mortality to these species compared to the slow growing, high wood density species. The collapse of forest elephant populations will likely therefore causes an increase in the abundance of fast growing tree species at the expense of slow growing species, and reduce the ability of the forest to capture carbon.
Stephen Blake, Ph.D., assistant professor of biology at Saint Louis University, spent 17 years in central Africa doing, among other things, applied research and conservation work with elephants. While there, he collected a data set on forest structure and species composition in the Nouabalé-Ndoki Forest of northern Congo.
In the current study, Blake's collaborators developed a mathematical computer model to answer the question 'What would happen to the composition of the forest over time with and without elephant browsing?'
To find out, they simulated elephant damage through browsing in the forest and assumed they browse certain plant species at different rates. Elephants prefer fast-growing species in more open spaces. As they feed and browse, they cause damage, knocking off a limb or breaking a shrub. The model calculated feeding and breakage rates along with elephant mortality rates to see their effect on certain woody plants.
"Lo and behold, as we look at numbers of elephants in a forest and we look at the composition of forest over time, we find that the proportion of trees with high density wood is higher in forests with elephants," Blake said.
"The simulation found that the slow-growing plant species survive better when elephants are present. These species aren't eaten by elephants and, over time, the forest becomes dominated by these slow-growing species. Wood (lignin) has a carbon backbone, meaning it has a large number of carbon molecules in it. Slow growing high wood density species contain more carbon molecules per unit volume than fast growing low wood density species. As the elephants "thin" the forest, they increase the number of slow-growing trees and the forest is capable of storing more carbon."
These findings suggest far-ranging ecological consequences of past and present extinctions. The loss of elephants will seriously reduce the ability of the remaining forest to sequester carbon. Trees and plants use carbon dioxide during photosynthesis, removing it from the atmosphere. For this reason, plants are helpful in combating global warming and serve to store carbon emissions.
Without the forest elephants, less carbon dioxide will be taken out of the atmosphere. In monetary terms, forest elephants represent a carbon storage service of $43 billion.
"The sad reality is that humanity is doing its best to rid the planet of elephants as quickly as it can," Blake said. "Forest elephants are rapidly declining and facing extinction. From a climate perspective, all of their positive effect on carbon and their myriad other ecological roles as forest gardeners and engineers will be lost."
The study authors note that forest elephant conservation could reverse this loss.
"Elephants are a flagship species. People love elephants -- we spend millions every year on cuddly toys, they are zoo favourites and who didn't cry during Dumbo? and yet we're pushing them closer to extinction every day. On one hand we admire them and feel empathy and are horrified when they are murdered and on the other hand we're not prepared to do anything serious about it. The consequences may be severe for us all. We need to change our ways.
Read more at Science Daily
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