Hundreds of thousands of volunteers have helped to overturn almost a century of galaxy classification, in a new study using data from the longstanding Galaxy Zoo project. The new investigation, published in the journal Monthly Notices of the Royal Astronomical Society, uses classifications of over 6000 galaxies to reveal that "well known" correlations between different features are not found in this large and complete sample.
Almost 100 years ago, in 1927, astronomer Edwin Hubble wrote about the spiral galaxies he was observing at the time, and developed a model to classify galaxies by type and shape. Known as the "Hubble Tuning Fork" due to its shape, this model takes account of two main features: the size of the central region (known as the 'bulge'), and how tightly wound any spiral arms are.
Hubble's model soon became the authoritative method of classifying spiral galaxies, and is still used widely in astronomy textbooks to this day. His key observation was that galaxies with larger bulges tended to have more tightly wound spiral arms, lending vital support to the 'density wave' model of spiral arm formation.
Now though, in contradiction to Hubble's model, the new work finds no significant correlation between the sizes of the galaxy bulges and how tightly wound the spirals are. This suggests that most spirals are not static density waves after all.
Galaxy Zoo Project Scientist and first author of the new work, Professor Karen Masters from Haverford College in the USA explains: "This non-detection was a big surprise, because this correlation is discussed in basically all astronomy textbooks -- it forms the basis of the spiral sequence described by Hubble."
Hubble was limited by the technology of the time, and could only observe the brightest nearby galaxies. The new work is based on a sample 15 times larger from the Galaxy Zoo project, where members of the public assess images of galaxies taken by telescopes around the world, identifying key features to help scientists to follow up and analyse in more detail.
"We always thought that the bulge size and winding of the spiral arms were connected," says Masters. "The new results suggest otherwise, and that has a big impact on our understanding of how galaxies develop their structure."
There are several proposed mechanisms for how spiral arms form in galaxies. One of the most popular is the density wave model -- the idea that the arms are not fixed structures, but caused by ripples in the density of material in the disc of the galaxy. Stars move in and out of these ripples as they pass around the galaxy.
New models however suggest that some arms at least could be real structures, not just ripples. These may consist of collections of stars that are bound by each other's gravity, and physically rotate together. This dynamic explanation for spiral arm formation is supported by state-of-the art computer models of spiral galaxies.
"It's clear that there is still lots of work to do to understand these objects, and it's great to have new eyes involved in the process," adds Brooke Simmons, Deputy Project Scientist for the Galaxy Zoo project.
Read more at Science Daily
Jun 11, 2019
An hour or two of outdoor learning every week increases teachers' job satisfaction
A Swansea University study has revealed how as little as an hour a week of outdoor learning has tremendous benefits for children and also boosts teachers' job satisfaction.
Through interviews and focus groups, researchers explored the views and experiences of pupils and educators at three primary schools in south Wales that had adopted an outdoor learning programme, which entailed teaching the curriculum in the natural environment for at least an hour a week.
Interviews were held with headteachers and teachers, and focus groups were conducted with pupils aged 9-11 both before and during the implementation of an outdoor learning programme within the curriculum.
The schools in the study reported a variety of benefits of outdoor learning for both the child and the teacher and for improving health, wellbeing, education and engagement in school.
Lead author of the study Emily Marchant, a PhD researcher in Medical Studies at Swansea University, explained: "We found that the pupils felt a sense of freedom when outside the restricting walls of the classroom. They felt more able to express themselves, and enjoyed being able to move about more too. They also said they felt more engaged and were more positive about the learning experience. We also heard many say that their well-being and memory were better, and teachers told us how it helped engage all types of learners."
The benefits of outdoor education for children are well documented, but a finding of this study is the impact that the outdoor learning programme had on teachers.
Emily said: "Initially, some teachers had reservations about transferring the classroom outdoors but once outdoor learning was embedded within the curriculum, they spoke of improved job satisfaction and personal wellbeing. This is a really important finding given the current concerns around teacher retention rates. Overall, our findings highlight the potential of outdoor learning as a curriculum tool in improving school engagement and the health, wellbeing and education outcomes of children.
"The schools within our study have all continued with regular outdoor learning within the curriculum. With support and recognition from education inspectorates of the wider benefits to children's development and education, outdoor learning could be set within the primary school curriculum."
From Science Daily
Through interviews and focus groups, researchers explored the views and experiences of pupils and educators at three primary schools in south Wales that had adopted an outdoor learning programme, which entailed teaching the curriculum in the natural environment for at least an hour a week.
Interviews were held with headteachers and teachers, and focus groups were conducted with pupils aged 9-11 both before and during the implementation of an outdoor learning programme within the curriculum.
The schools in the study reported a variety of benefits of outdoor learning for both the child and the teacher and for improving health, wellbeing, education and engagement in school.
Lead author of the study Emily Marchant, a PhD researcher in Medical Studies at Swansea University, explained: "We found that the pupils felt a sense of freedom when outside the restricting walls of the classroom. They felt more able to express themselves, and enjoyed being able to move about more too. They also said they felt more engaged and were more positive about the learning experience. We also heard many say that their well-being and memory were better, and teachers told us how it helped engage all types of learners."
The benefits of outdoor education for children are well documented, but a finding of this study is the impact that the outdoor learning programme had on teachers.
Emily said: "Initially, some teachers had reservations about transferring the classroom outdoors but once outdoor learning was embedded within the curriculum, they spoke of improved job satisfaction and personal wellbeing. This is a really important finding given the current concerns around teacher retention rates. Overall, our findings highlight the potential of outdoor learning as a curriculum tool in improving school engagement and the health, wellbeing and education outcomes of children.
"The schools within our study have all continued with regular outdoor learning within the curriculum. With support and recognition from education inspectorates of the wider benefits to children's development and education, outdoor learning could be set within the primary school curriculum."
From Science Daily
Genetics influence how protective childhood vaccines are for individual infants
A genome-wide search in thousands of children in the UK and Netherlands has revealed genetic variants associated with differing levels of protective antibodies produced after routine childhood immunizations. The findings, appearing June 11 in the journal Cell Reports, may inform the development of new vaccine strategies and could lead to personalized vaccination schedules to maximize vaccine effectiveness.
"This study is the first to use a genome-wide genotyping approach, assessing several million genetic variants, to investigate the genetic determinants of immune responses to three routine childhood vaccines," says Daniel O'Connor of the University of Oxford, who is co-first author on the paper along with Eileen Png of the Genome Institute of Singapore. "While this study is a good start, it also clearly demonstrates that more work is needed to fully describe the complex genetics involved in vaccine responses, and to achieve this aim we will need to study many more individuals."
Vaccines have revolutionized public health, preventing millions of deaths each year, particularly in childhood. The maintenance of antibody levels in the blood is essential for continued vaccine-induced protection against pathogens. Yet there is considerable variability in the magnitude and persistence of vaccine-induced immunity. Moreover, antibody levels rapidly wane following immunization with certain vaccines in early infancy, so boosters are required to sustain protection.
"Evoking robust and sustained vaccine-induced immunity from early life is a crucial component of global health initiatives to combat the burden of infectious disease," O'Connor says. "The mechanisms underlying the persistence of antibody is of major interest, since effectiveness and acceptability of vaccines would be improved if protection were sustained after infant immunization without the need for repeated boosting through childhood."
Vaccine responses and the persistence of immunity are determined by various factors, including age, sex, ethnicity, microbiota, nutritional status, and infectious diseases. Twin studies have also shown vaccine-induced immunity to be highly heritable, and recent studies have started to unpick the genetic components underlying this complex trait.
To explore genetic factors that determine the persistence of immunity, O'Connor and colleagues carried out a genome-wide association study of 3,602 children in the UK and Netherlands. The researchers focused on three routine childhood vaccines that protect against life-threatening bacterial infections: capsular group C meningococcal (MenC), Haemophilus influenzae type b (Hib), and tetanus toxoid (TT) vaccines. They analyzed approximately 6.7 million genetic variants affecting a single DNA building block, known as single nucleotide polymorphisms (SNPs), associated with vaccine-induced antibody levels in the blood.
The researchers identified two genetic loci associated with the persistence of vaccine-induced immunity following childhood immunization. The persistence of MenC immunity is associated with SNPs in a genomic region containing a family of signal-regulatory proteins, which are involved in immunological signaling. Meanwhile, the persistence of TT-specific immunity is associated with SNPs in the human leukocyte antigen (HLA) locus. HLA molecules present peptides to T cells, which in turn induce B cells to produce antibodies.
These variants likely account for only a small portion of the genetic determinants of persistence of vaccine-induced immunity. Moreover, it is unclear whether the findings apply to other ethnic populations besides Caucasians from the UK and Netherlands. But according to the authors, neonatal screening approaches could soon incorporate genetic risk factors that predict the persistence of immunity, paving the way for personalized vaccine regimens.
Read more at Science Daily
"This study is the first to use a genome-wide genotyping approach, assessing several million genetic variants, to investigate the genetic determinants of immune responses to three routine childhood vaccines," says Daniel O'Connor of the University of Oxford, who is co-first author on the paper along with Eileen Png of the Genome Institute of Singapore. "While this study is a good start, it also clearly demonstrates that more work is needed to fully describe the complex genetics involved in vaccine responses, and to achieve this aim we will need to study many more individuals."
Vaccines have revolutionized public health, preventing millions of deaths each year, particularly in childhood. The maintenance of antibody levels in the blood is essential for continued vaccine-induced protection against pathogens. Yet there is considerable variability in the magnitude and persistence of vaccine-induced immunity. Moreover, antibody levels rapidly wane following immunization with certain vaccines in early infancy, so boosters are required to sustain protection.
"Evoking robust and sustained vaccine-induced immunity from early life is a crucial component of global health initiatives to combat the burden of infectious disease," O'Connor says. "The mechanisms underlying the persistence of antibody is of major interest, since effectiveness and acceptability of vaccines would be improved if protection were sustained after infant immunization without the need for repeated boosting through childhood."
Vaccine responses and the persistence of immunity are determined by various factors, including age, sex, ethnicity, microbiota, nutritional status, and infectious diseases. Twin studies have also shown vaccine-induced immunity to be highly heritable, and recent studies have started to unpick the genetic components underlying this complex trait.
To explore genetic factors that determine the persistence of immunity, O'Connor and colleagues carried out a genome-wide association study of 3,602 children in the UK and Netherlands. The researchers focused on three routine childhood vaccines that protect against life-threatening bacterial infections: capsular group C meningococcal (MenC), Haemophilus influenzae type b (Hib), and tetanus toxoid (TT) vaccines. They analyzed approximately 6.7 million genetic variants affecting a single DNA building block, known as single nucleotide polymorphisms (SNPs), associated with vaccine-induced antibody levels in the blood.
The researchers identified two genetic loci associated with the persistence of vaccine-induced immunity following childhood immunization. The persistence of MenC immunity is associated with SNPs in a genomic region containing a family of signal-regulatory proteins, which are involved in immunological signaling. Meanwhile, the persistence of TT-specific immunity is associated with SNPs in the human leukocyte antigen (HLA) locus. HLA molecules present peptides to T cells, which in turn induce B cells to produce antibodies.
These variants likely account for only a small portion of the genetic determinants of persistence of vaccine-induced immunity. Moreover, it is unclear whether the findings apply to other ethnic populations besides Caucasians from the UK and Netherlands. But according to the authors, neonatal screening approaches could soon incorporate genetic risk factors that predict the persistence of immunity, paving the way for personalized vaccine regimens.
Read more at Science Daily
How the brain changes when mastering a new skill
Mastering a new skill -- whether a sport, an instrument, or a craft -- takes time and training. While it is understood that a healthy brain is capable of learning these new skills, how the brain changes in order to develop new behaviors is a relative mystery. More precise knowledge of this underlying neural circuitry may eventually improve the quality of life for individuals who have suffered brain injury by enabling them to more easily relearn everyday tasks.
Researchers from the University of Pittsburgh and Carnegie Mellon University recently published an article in PNAS that reveals what happens in the brain as learners progress from novice to expert. They discovered that new neural activity patterns emerge with long-term learning and established a causal link between these patterns and new behavioral abilities.
The research was performed as part of the Center for the Neural Basis of Cognition, a cross-institutional research and education program that leverages the strengths of Pitt in basic and clinical neuroscience and bioengineering, with those of CMU in cognitive and computational neuroscience.
The project was jointly mentored by Aaron Batista, associate professor of bioengineering at Pitt; Byron Yu, associate professor of electrical and computer engineering and biomedical engineering at CMU; and Steven Chase, associate professor of biomedical engineering and the Neuroscience Institute at CMU. The work was led by Pitt bioengineering postdoctoral associate Emily Oby.
"We used a brain-computer interface (BCI), which creates a direct connection between our subject's neural activity and the movement of a computer cursor," said Oby. "We recorded the activity of around 90 neural units in the arm region of the primary motor cortex of Rhesus monkeys as they performed a task that required them to move the cursor to align with targets on the monitor."
To determine whether the monkeys would form new neural patterns as they learned, the research group encouraged the animals to attempt a new BCI skill and then compared those recordings to the pre-existing neural patterns.
"We first presented the monkey with what we call an 'intuitive mapping' from their neural activity to the cursor that worked with how their neurons naturally fire and which didn't require any learning," said Oby. "We then induced learning by introducing a skill in the form of a novel mapping that required the subject to learn what neural patterns they need to produce in order to move the cursor."
Like learning most skills, the group's BCI task took several sessions of practice and a bit of coaching along the way.
"We discovered that after a week, our subject was able to learn how to control the cursor," said Batista. "This is striking because by construction, we knew from the outset that they did not have the neural activity patterns required to perform this skill. Sure enough, when we looked at the neural activity again after learning we saw that new patterns of neural activity had appeared, and these new patterns are what enabled the monkey to perform the task."
These findings suggest that the process for humans to master a new skill might also involve the generation of new neural activity patterns.
"Though we are looking at this one specific task in animal subjects, we believe that this is perhaps how the brain learns many new things," said Yu. "Consider learning the finger dexterity required to play a complex piece on the piano. Prior to practice, your brain might not yet be capable of generating the appropriate activity patterns to produce the desired finger movements."
Read more at Science Daily
Researchers from the University of Pittsburgh and Carnegie Mellon University recently published an article in PNAS that reveals what happens in the brain as learners progress from novice to expert. They discovered that new neural activity patterns emerge with long-term learning and established a causal link between these patterns and new behavioral abilities.
The research was performed as part of the Center for the Neural Basis of Cognition, a cross-institutional research and education program that leverages the strengths of Pitt in basic and clinical neuroscience and bioengineering, with those of CMU in cognitive and computational neuroscience.
The project was jointly mentored by Aaron Batista, associate professor of bioengineering at Pitt; Byron Yu, associate professor of electrical and computer engineering and biomedical engineering at CMU; and Steven Chase, associate professor of biomedical engineering and the Neuroscience Institute at CMU. The work was led by Pitt bioengineering postdoctoral associate Emily Oby.
"We used a brain-computer interface (BCI), which creates a direct connection between our subject's neural activity and the movement of a computer cursor," said Oby. "We recorded the activity of around 90 neural units in the arm region of the primary motor cortex of Rhesus monkeys as they performed a task that required them to move the cursor to align with targets on the monitor."
To determine whether the monkeys would form new neural patterns as they learned, the research group encouraged the animals to attempt a new BCI skill and then compared those recordings to the pre-existing neural patterns.
"We first presented the monkey with what we call an 'intuitive mapping' from their neural activity to the cursor that worked with how their neurons naturally fire and which didn't require any learning," said Oby. "We then induced learning by introducing a skill in the form of a novel mapping that required the subject to learn what neural patterns they need to produce in order to move the cursor."
Like learning most skills, the group's BCI task took several sessions of practice and a bit of coaching along the way.
"We discovered that after a week, our subject was able to learn how to control the cursor," said Batista. "This is striking because by construction, we knew from the outset that they did not have the neural activity patterns required to perform this skill. Sure enough, when we looked at the neural activity again after learning we saw that new patterns of neural activity had appeared, and these new patterns are what enabled the monkey to perform the task."
These findings suggest that the process for humans to master a new skill might also involve the generation of new neural activity patterns.
"Though we are looking at this one specific task in animal subjects, we believe that this is perhaps how the brain learns many new things," said Yu. "Consider learning the finger dexterity required to play a complex piece on the piano. Prior to practice, your brain might not yet be capable of generating the appropriate activity patterns to produce the desired finger movements."
Read more at Science Daily
Jun 10, 2019
Predicting seizures before they happen
A new study has found a pattern of molecules that appear in the blood before a seizure happens. This discovery may lead to the development of an early warning system, which would enable people with epilepsy to know when they are at risk of having a seizure.
Researchers at FutureNeuro, the SFI Research Centre for Chronic and Rare Neurological Diseases, hosted at RCSI (Royal College of Surgeons in Ireland) led the study, which is published in the current edition of the Journal of Clinical Investigation (JCI).
FutureNeuro and RCSI researchers have discovered molecules in the blood that are higher in people with epilepsy before a seizure happens. These molecules are fragments of transfer RNAs (tRNAs), a chemical closely related to DNA that performs an important role in building proteins within the cell. When cells are stressed, tRNAs are cut into fragments. Higher levels of the fragments in the blood could reflect that brain cells are under stress in the build up to a seizure event.
Using blood samples from people with epilepsy at the Epilepsy Monitoring Unit in Beaumont Hospital, Dublin and in a similar specialist centre in Marburg, Germany, the group found that fragment levels of three tRNAs "spike" in the blood many hours before a seizure.
"People with epilepsy often report that one of the most difficult aspects of living with the disease is never knowing when a seizure will occur," said Dr Marion Hogg, FutureNeuro investigator, Honorary Lecturer at RCSI, and the study's lead author.
"The results of this study are very promising. We hope that our tRNA research will be a key first step toward developing an early warning system."
Approximately 40,000 people in Ireland have epilepsy and one third of those do not respond to current treatments, meaning they continue to experience seizures. The World Health Organisation estimates that more than 50 million people worldwide have epilepsy.
"New technologies to remove the unpredictability of uncontrolled seizures for people with epilepsy are a very real possibility," said Professor David Henshall, Director of FutureNeuro and Professor of Molecular Physiology and Neuroscience at RCSI who was a co-author on the paper.
Read more at Science Daily
Researchers at FutureNeuro, the SFI Research Centre for Chronic and Rare Neurological Diseases, hosted at RCSI (Royal College of Surgeons in Ireland) led the study, which is published in the current edition of the Journal of Clinical Investigation (JCI).
FutureNeuro and RCSI researchers have discovered molecules in the blood that are higher in people with epilepsy before a seizure happens. These molecules are fragments of transfer RNAs (tRNAs), a chemical closely related to DNA that performs an important role in building proteins within the cell. When cells are stressed, tRNAs are cut into fragments. Higher levels of the fragments in the blood could reflect that brain cells are under stress in the build up to a seizure event.
Using blood samples from people with epilepsy at the Epilepsy Monitoring Unit in Beaumont Hospital, Dublin and in a similar specialist centre in Marburg, Germany, the group found that fragment levels of three tRNAs "spike" in the blood many hours before a seizure.
"People with epilepsy often report that one of the most difficult aspects of living with the disease is never knowing when a seizure will occur," said Dr Marion Hogg, FutureNeuro investigator, Honorary Lecturer at RCSI, and the study's lead author.
"The results of this study are very promising. We hope that our tRNA research will be a key first step toward developing an early warning system."
Approximately 40,000 people in Ireland have epilepsy and one third of those do not respond to current treatments, meaning they continue to experience seizures. The World Health Organisation estimates that more than 50 million people worldwide have epilepsy.
"New technologies to remove the unpredictability of uncontrolled seizures for people with epilepsy are a very real possibility," said Professor David Henshall, Director of FutureNeuro and Professor of Molecular Physiology and Neuroscience at RCSI who was a co-author on the paper.
Read more at Science Daily
Night owls can 'retrain' their body clocks to improve mental well-being and performance
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| 'Night owl' concept |
New international research by the Universities of Birmingham and Surrey in the UK, and Monash University in Australia, showed that, over a three-week period, it was possible to shift the circadian rhythm of 'night owls' using non-pharmacological and practical interventions.
The study, recently published in Sleep Medicine, showed participants were able to bring forward their sleep/wake timings by two hours, while having no negative effect on sleep duration. In addition, participants reported a decrease in feelings of depression and stress, as well as in daytime sleepiness.
"Our research findings highlight the ability of a simple non-pharmacological intervention to phase advance 'night owls', reduce negative elements of mental health and sleepiness, as well as manipulate peak performance times in the real world," lead researcher Dr Elise Facer-Childs from Monash University's Turner Institute for Brain and Mental Health said.
'Night owls' are individuals whose internal body clock dictates later-than-usual sleep and wake times -- in this study participants had an average bedtime of 2.30am and wake-up time of 10.15am.
Disturbances to the sleep/wake system have been linked to a variety of health issues, including mood swings, increased morbidity and mortality rates, and declines in cognitive and physical performance.
"Having a late sleep pattern puts you at odds with the standard societal days, which can lead to a range of adverse outcomes -- from daytime sleepiness to poorer mental wellbeing," study co-author Dr Andrew Bagshaw from the University of Birmingham said.
"We wanted to see if there were simple things people could do at home to solve this issue. This was successful, on average allowing people to get to sleep and wake up around two hours earlier than they were before. Most interestingly, this was also associated with improvements in mental wellbeing and perceived sleepiness, meaning that it was a very positive outcome for the participants. We now need to understand how habitual sleep patterns are related to the brain, how this links with mental wellbeing and whether the interventions lead to long-term changes."
Twenty-two healthy individuals participated in the study. For a period of three weeks participants in the experimental group were asked to:
- Wake up 2-3 hours before regular wake up time and maximise outdoor light during the mornings.
- Go to bed 2-3 hours before habitual bedtime and limit light exposure in the evening.
- Keep sleep/wake times fixed on both work days and free days.
- Have breakfast as soon as possible after waking up, eat lunch at the same time each day, and refrain from eating dinner after 7pm.
The results highlighted an increase in cognitive (reaction time) and physical (grip strength) performance during the morning when tiredness is often very high in 'night owls', as well as a shift in peak performance times from evening to afternoon. It also increased the number of days in which breakfast was consumed and led to better mental well-being, with participants reporting a decrease in feelings of stress and depression.
"Establishing simple routines could help 'night owls' adjust their body clocks and improve their overall physical and mental health. Insufficient levels of sleep and circadian misalignment can disrupt many bodily processes putting us at increased risk of cardiovascular disease, cancer and diabetes," Professor Debra Skene from the University of Surrey said.
Dr Facer-Childs said 'night owls', compared to 'morning larks', tended to be more compromised in our society due to having to fit to work/school schedules that are out of sync with their preferred patterns.
"By acknowledging these differences and providing tools to improve outcomes we can go a long way in a society that is under constant pressure to achieve optimal productivity and performance," she said.
Read more at Science Daily
Site of biggest ever meteorite collision in the UK discovered
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| Illustration of meteors streaking through Earth's atmosphere. |
Evidence for the ancient, 1.2 billion years old, meteorite strike, was first discovered in 2008 near Ullapool, NW Scotland by scientists from Oxford and Aberdeen Universities. The thickness and extent of the debris deposit they found suggested the impact crater -- made by a meteorite estimated at 1km wide -- was close to the coast, but its precise location remained a mystery.
In a paper published today in Journal of the Geological Society, a team led by Dr Ken Amor from the Department of Earth Sciences at Oxford University, show how they have identified the crater location 15-20km west of a remote part of the Scottish coastline. It is buried beneath both water and younger rocks in the Minch Basin.
Dr Ken Amor said: 'The material excavated during a giant meteorite impact is rarely preserved on Earth, because it is rapidly eroded, so this is a really exciting discovery. It was purely by chance this one landed in an ancient rift valley where fresh sediment quickly covered the debris to preserve it.
'The next step will be a detailed geophysical survey in our target area of the Minch Basin.'
Using a combination of field observations, the distribution of broken rock fragments known as basement clasts and the alignment of magnetic particles, the team was able to gauge the direction the meteorite material took at several locations, and plotted the likely source of the crater.
Dr Ken Amor said: 'It would have been quite a spectacle when this large meteorite struck a barren landscape, spreading dust and rock debris over a wide area.'
1.2 billion years ago most of life on Earth was still in the oceans and there were no plants on the land. At that time Scotland would have been quite close to the equator and in a semi-arid environment. The landscape would have looked a bit like Mars when it had water at the surface.
Earth and other planets may have suffered a higher rate of meteorite impacts in the distant past, as they collided with debris left over from the formation of the early solar system.
However, there is a possibility that a similar event will happen in the future given the number of asteroid and comet fragments floating around in the solar system. Much smaller impacts, where the meteorite is only a few meters across are thought to be relatively common perhaps occurring about once every 25 years on average.
It is thought that collisions with an object about 1 km (as in this instance) across occur between once every 100,000 years to once every one million years -- but estimates vary.
Read more at Science Daily
Mass anomaly detected under the moon's largest crater
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| Illustration of far side of the moon |
"Imagine taking a pile of metal five times larger than the Big Island of Hawaii and burying it underground. That's roughly how much unexpected mass we detected," said lead author Peter B. James,
Ph.D., assistant professor of planetary geophysics in Baylor's College of Arts & Sciences. The crater itself is oval-shaped, as wide as 2,000 kilometers -- roughly the distance between Waco, Texas, and Washington, D.C. -- and several miles deep. Despite its size, it cannot be seen from Earth because it is on the far side of the Moon.
The study -- "Deep Structure of the Lunar South Pole-Aitken Basin" -- is published in the journal Geophysical Research Letters.
To measure subtle changes in the strength of gravity around the Moon, researchers analyzed data from spacecrafts used for the National Aeronautics and Space Administration (NASA) Gravity Recovery and Interior Laboratory (GRAIL) mission.
"When we combined that with lunar topography data from the Lunar Reconnaissance Orbiter, we discovered the unexpectedly large amount of mass hundreds of miles underneath the South Pole-Aitken basin," James said. "One of the explanations of this extra mass is that the metal from the asteroid that formed this crater is still embedded in the Moon's mantle."
The dense mass -- "whatever it is, wherever it came from" -- is weighing the basin floor downward by more than half a mile, he said. Computer simulations of large asteroid impacts suggest that, under the right conditions, an iron-nickel core of an asteroid may be dispersed into the upper mantle (the layer between the Moon's crust and core) during an impact.
"We did the math and showed that a sufficiently dispersed core of the asteroid that made the impact could remain suspended in the Moon's mantle until the present day, rather than sinking to the Moon's core," James said.
Another possibility is that the large mass might be a concentration of dense oxides associated with the last stage of lunar magma ocean solidification.
James said that the South Pole-Aitken basin -- thought to have been created about 4 billion years ago -- is the largest preserved crater in the solar system. While larger impacts may have occurred throughout the solar system, including on Earth, most traces of those have been lost.
James called the basin "one of the best natural laboratories for studying catastrophic impact events, an ancient process that shaped all of the rocky planets and moons we see today."
This research was supported through the NASA Gravity Recovery and Interior Laboratory (GRAIL) science team.
Read more at Science Daily
Jun 9, 2019
The mystery of the galaxy with no dark matter
Galaxies with no dark matter are impossible to understand in the framework of the current theory of galaxy formation, because the role of dark matter is fundamental in causing the collapse of the gas to form stars. In 2018, a study published inNature magazine announced the discovery of a galaxy that lacked dark matter, which made a strong impact, and occupied the covers of popular scientific magazines.
Now, according to an article published in the Monthly Notices of the Royal Astronomical Society (MNRAS) a group of researchers at the Instituto de Astrofísica de Canarias (IAC) has solved this mystery via a very complete set of observations of KKS2000]04 (NGC1052-DF2), previously nicknamed "the galaxy without dark matter."
In this study the researchers, perplexed because all the parameters that depended on the distance of the galaxy were anomalous; have revised the available distance indicators. Using five independent methods to estimate the distance of the object they found that all of them coincided in one conclusion: the galaxy is much nearer than the value presented in the previous research.
The original article published in Nature stated that the galaxy is at a distance of some 64 million light years from Earth. However, this new research has revealed that the real distance is much less, around 42 million light years.
Thanks to these new results, the parameters of the galaxy inferred from its distance have become "normal" and fit the observed trends traced by galaxies with similar characteristics.
The most relevant datum that has been found via the new distance analysis is that the total mass of this galaxy is around a half of the mass estimated previously, but the mass of its stars is only about quarter of the previously estimated mass. This implies that a significant part of the total mass must be made up of dark matter. The results of this work show the fundamental importance of the correct measurement of extragalactic distances. It has always been one of the most challenging tasks in astrophysics: how to measure the distances to objects which are very far away and which we cannot touch.
From Science Daily
Now, according to an article published in the Monthly Notices of the Royal Astronomical Society (MNRAS) a group of researchers at the Instituto de Astrofísica de Canarias (IAC) has solved this mystery via a very complete set of observations of KKS2000]04 (NGC1052-DF2), previously nicknamed "the galaxy without dark matter."
In this study the researchers, perplexed because all the parameters that depended on the distance of the galaxy were anomalous; have revised the available distance indicators. Using five independent methods to estimate the distance of the object they found that all of them coincided in one conclusion: the galaxy is much nearer than the value presented in the previous research.
The original article published in Nature stated that the galaxy is at a distance of some 64 million light years from Earth. However, this new research has revealed that the real distance is much less, around 42 million light years.
Thanks to these new results, the parameters of the galaxy inferred from its distance have become "normal" and fit the observed trends traced by galaxies with similar characteristics.
The most relevant datum that has been found via the new distance analysis is that the total mass of this galaxy is around a half of the mass estimated previously, but the mass of its stars is only about quarter of the previously estimated mass. This implies that a significant part of the total mass must be made up of dark matter. The results of this work show the fundamental importance of the correct measurement of extragalactic distances. It has always been one of the most challenging tasks in astrophysics: how to measure the distances to objects which are very far away and which we cannot touch.
From Science Daily
How genes interact to build tissues and organisms
Although the knowledge we have about human cells and tissues has steadily increased over recent decades, many things remain unknown. For instance, cells exist in transient, dynamic states and understanding them is fundamental to decipher diseases and find cures. Classic techniques used in the lab to study cell types faced limitations and did not enable a finely detailed profile of cell function.
To overcome this obstacle, a group of scientists at the National Centre for Genomic Analysis (CNAG-CRG) from the Centre for Genomic Regulation (CRG), in Barcelona, Spain, led by Holger Heyn, developed a new computational tool, based on the mathematical Graph theory, to infer global, large-scale regulatory networks, from healthy and pathological organs, such as those affected by diabetes or Alzheimer's disease. The researchers were able to pinpoint genes relevant to organ function and potential drivers of diseases. They are publishing their results in the current issue of the Genome Biology journal.
"Our previously developed single-cell transcriptomic tools were very useful to discover unknown cell types," says Giovanni Iacono, senior postdoc researcher at the CNAG-CRG and first author of the study. "Those tools allowed us to describe new types and subtypes of cells, with their unique biological roles and hierarchical relationships," he adds.
Up to now, single-cell analysis had been used to understand cell types and their function within tissue. "Large-scale consortia like the Human Cell Atlas Project generate single-cell maps of entire organisms and sophisticated analysis strategies are required to transform big data into disruptive biological and clinical insights," says Holger Heyn, team leader of the Single Cell Genomics Group at the CNAG-CRG and senior author of the article.
The tool that this scientific team has now developed will enable them to go one step further, to see how genes interact to form tissues. "Our tool tries to address precisely the regulatory process that controls the morphology and functions of a cell," highlights Iacono.
The tool is based on the Graph theory, an abstract mathematical model in which there are nodes connected by edges. Once you have a graph, a structure, you can measure the importance of each node for the network. In this case, each node was a gene and importance was defined as the function of that gene being key for the biological system under study.
CNAG-CRG researchers processed datasets from ten-thousands of cells to infer the regulatory networks that drive cell phenotype formation and their respective functions. They applied their tool to study type 2 diabetes and Alzheimer's disease and were able to find the functional changes relevant to those diseases. Importantly, this opens the door to finding new drug targets.
"The network analysis we have developed goes beyond currently applied approaches to provide deep insights into how gene activities shape tissues and organs. This is critical to understand diseases in which these networks are disrupted and find their 'Achilles heels' for effective treatments." says Heyn.
Read more at Science Daily
To overcome this obstacle, a group of scientists at the National Centre for Genomic Analysis (CNAG-CRG) from the Centre for Genomic Regulation (CRG), in Barcelona, Spain, led by Holger Heyn, developed a new computational tool, based on the mathematical Graph theory, to infer global, large-scale regulatory networks, from healthy and pathological organs, such as those affected by diabetes or Alzheimer's disease. The researchers were able to pinpoint genes relevant to organ function and potential drivers of diseases. They are publishing their results in the current issue of the Genome Biology journal.
"Our previously developed single-cell transcriptomic tools were very useful to discover unknown cell types," says Giovanni Iacono, senior postdoc researcher at the CNAG-CRG and first author of the study. "Those tools allowed us to describe new types and subtypes of cells, with their unique biological roles and hierarchical relationships," he adds.
Up to now, single-cell analysis had been used to understand cell types and their function within tissue. "Large-scale consortia like the Human Cell Atlas Project generate single-cell maps of entire organisms and sophisticated analysis strategies are required to transform big data into disruptive biological and clinical insights," says Holger Heyn, team leader of the Single Cell Genomics Group at the CNAG-CRG and senior author of the article.
The tool that this scientific team has now developed will enable them to go one step further, to see how genes interact to form tissues. "Our tool tries to address precisely the regulatory process that controls the morphology and functions of a cell," highlights Iacono.
The tool is based on the Graph theory, an abstract mathematical model in which there are nodes connected by edges. Once you have a graph, a structure, you can measure the importance of each node for the network. In this case, each node was a gene and importance was defined as the function of that gene being key for the biological system under study.
CNAG-CRG researchers processed datasets from ten-thousands of cells to infer the regulatory networks that drive cell phenotype formation and their respective functions. They applied their tool to study type 2 diabetes and Alzheimer's disease and were able to find the functional changes relevant to those diseases. Importantly, this opens the door to finding new drug targets.
"The network analysis we have developed goes beyond currently applied approaches to provide deep insights into how gene activities shape tissues and organs. This is critical to understand diseases in which these networks are disrupted and find their 'Achilles heels' for effective treatments." says Heyn.
Read more at Science Daily
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