Monday, October 22, 2018

Enipniastes Eximia, The "Headless Chicken Monster" from the Deep



New underwater camera technology developed by Australian researchers is shining a light on previously unseen species in the Southern Ocean to help improve marine conservation.

For the first time, a deep-sea swimming sea cucumber, Enypniastes eximia, also known as a “headless chicken monster”, has been filmed in Southern Ocean waters off East Antarctica.

The unusual creature, which has only ever been filmed before in the Gulf of Mexico, was discovered using an underwater camera system developed for commercial long-line fishing by the Australian Antarctic Division.

Enipniastes eximia, the "headless chicken monster" 
Photo: NOAA

Australian Antarctic Division Program Leader Dr Dirk Welsford, said the cameras are capturing important data which is being fed into the international body managing the Southern Ocean, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR).

“The housing that protects the camera and electronics is designed to attach to toothfish longlines in the Southern Ocean, so it needs to be extremely durable,” Dr Welsford said.

“We needed something that could be thrown from the side of a boat, and would continue operating reliably under extreme pressure in the pitch black for long periods of time.”

“Some of the footage we are getting back from the cameras is breathtaking, including species we have never seen in this part of the world.”
Credit: Australian Antarctic Division

“Most importantly, the cameras are providing important information about areas of sea floor that can withstand this type of fishing, and sensitive areas that should be avoided.”

Dr Welsford said other CCAMLR nations, such as Chile, France, and the United Kingdom are now also using the super-strengthened devices, which are fabricated at the AAD’s headquarters in Tasmania.

“It’s a really simple and practical solution which is directly contributing to improving sustainable fishing practices,” Dr Welsford said.

The data collected from the cameras are being presented at the annual CCAMLR meeting starting in Hobart tomorrow.

Australia’s CCAMLR Commissioner, Ms Gillian Slocum, said Australia will continue to lead on the most pressing issues facing the Southern Ocean, including biodiversity conservation, climate change and science-based fisheries management.

“Australia will again be seeking support for the creation of a new East Antarctic Marine Protected Area,” Ms Slocum said.

“We will also support two other new Marine Protected Areas being proposed this year which will contribute to CCAMLR’s commitment of a representative system of MPAs in the Southern Ocean.”

These proposals are among a number of measures Australia will put forward during the 10-day meeting, including proposals to improve the way CCAMLR responds to the impacts of climate change.

“The Southern Ocean is home to an incredible abundance and variety of marine life, including commercially sought-after species, the harvesting of which must be carefully managed for future generations,” Ms Slocum said.


Contacts and sources: 
Australian Antarctic Division

Humans and Neanderthals Share Rock Art Gallery in The Cave Las Ventanas

Humans and Neanderthals may have interacted in Spain in southwest Europe, according to the art on the cave wall. 

A paper has just been published in PLOS ONE which confirms an age of 35,000 years for the oldest engravings found in The Cave Las Ventanas located in Granada (Spain)

According to the authors, "The south of Iberia conserves an important group of Palaeolithic rock art sites. The graphisms have been mostly attributed to the Solutrean and Magdalenian periods, while the possibility that older remains exist has provoked extensive debate. This circumstance has been linked to both the cited periods, until recently, due to the transition from the Middle to Upper Palaeolithic in the extreme southwest of Europe as well as the non-existence of some of the early periods of Palaeolithic art documented in northern Iberia"

The Solutrean toolkit includes the world's earliest identifiable sewing needles.


Their study presents the results of interdisciplinary research conducted in Las Ventanas Cave. These results enabled us to identify a new Palaeolithic rock art site. The technical, stylistic and temporal traits point to certain similarities with the range of exterior deep engravings in Cantabrian Palaeolithic rock art. Ventanas appears to corroborate the age attributed to those kinds of graphic expression and points to the early arrival of the Upper Palaeolithic in the south of Iberia. 

Importantly, the results provide information on the pre-Solutrean date attributed to trilinear hind figures. These findings challenge the supposed Neanderthal survival idea at one of the main late Middle Palaeolithic southern Iberian sites (Carigüela) and, due to the parallels between them and an engraving attributed to this period in Gibraltar, it raises the possibility of interaction between modern humans and Neanderthals in the extreme southwest of Europe.

The Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) has participated in a study led by the Universidad de Sevilla and published in the journal PLOS ONE, on the Paleolithic engravings in the cave Las Ventanas , one of the highest sites (at 1015 meters) where rock art has been found in the Iberian Peninsula.

Landscape of Andalusia, view from the caves of Las Ventanas, Pinar.
File:Landscape andalusia pinar.jpg
Credit: Jebulon / Wikimedia Commons

The Uranium Series Laboratory of the CENIEH has collaborated in establishing the chronological framework, and an age of 35,000 years has been confirmed for the oldest rock art found in this cave in the province of Granada, situated in the Sierra de Arana (Píñar).

“The dates we have obtained at the CENIEH, using multi-collector plasma source mass spectrometry, confirm the results of the carbon-14 analysis, using accelerator mass spectrometry, helping to underpin the ages calculated", comments Fernando Jiménez Barrido, from the Uranium Series Laboratory.

Fernando Jiménez Barredo a the URanium Series Laboratory

Credit: CENIEH

Specifically, two groups of engravings of different ages have been found: one dating from between the end of the Pleistocene and the start of the Holocene (8,500 – 15,000 years ago), and another going as far back as 35,000 years.

The technical and thematic “proximity” between the hundreds of engravings in this cave may open up, with all due caution, a way of identifying possible interactions between modern humans and Neanderthals.



Contacts and sources:     .
CENIEH
http://www.cenieh.es/en/inicio

Citation:   Pre-Solutrean rock art in southernmost Europe: Evidence from Las Ventanas Cave (Andalusia, Spain)
Cortés-Sánchez M, Riquelme-Cantal JA, Simón-Vallejo MD, Parrilla Giráldez R, Odriozola CP, et al. (2018) Pre-Solutrean rock art in southernmost Europe: Evidence from Las Ventanas Cave (Andalusia, Spain). PLOS ONE 13(10): e0204651. https://doi.org/10.1371/journal.pone.0204651   .



Sunday, October 21, 2018

'J waves' Indicate Earth’s Inner Core Is Solid

A new study by researchers at The Australian National University (ANU) could help us understand how our planet was formed.

Associate Professor Hrvoje Tkalčić and PhD Scholar Than-Son Phạm are confident they now have direct proof the earth's inner core is solid.

They came up with a way to detect shear waves, or "J waves" in the inner core - a type of wave which can only travel through solid objects.

Earth and atmosphere cutaway illustration
Earth-crust-cutaway-english.svg
Credit: Surachit / Wikimedia Commons

"We found the inner core is indeed solid, but we also found that it's softer than previously thought," Associate Professor Tkalčić said.

"It turns out - if our results are correct - the inner core shares some similar elastic properties with gold and platinum. The inner core is like a time capsule, if we understand it we'll understand how the planet was formed, and how it evolves."

Inner core shear waves are so tiny and feeble they can't be observed directly. In fact, detecting them has been considered the "Holy Grail" of global seismology since scientists first predicted the inner core was solid in the 1930s and 40s.

So the researchers had to come up with a creative approach.

Their so-called correlation wavefield method looks at the similarities between the signals at two receivers after a major earthquake, rather than the direct wave arrivals. A similar technique has been used by the same team to measure the thickness of the ice in Antarctica.

"We're throwing away the first three hours of the seismogram and what we're looking at is between three and 10 hours after a large earthquake happens. We want to get rid of the big signals," Dr Tkalčic said.

"Using a global network of stations, we take every single receiver pair and every single large earthquake - that's many combinations - and we measure the similarity between the seismograms. That's called cross correlation, or the measure of similarity. From those similarities we construct a global correlogram - a sort of fingerprint of the earth."

The study shows these results can then be used to demonstrate the existence of J waves and infer the shear wave speed in the inner core.

While this specific information about shear waves is important, Dr Tkalčić says what this research tells us about the inner core is even more exciting.

"For instance we don't know yet what the exact temperature of the inner core is, what the age of the inner core is, or how quickly it solidifies, but with these new advances in global seismology, we are slowly getting there.

"The understanding of the Earth's inner core has direct consequences for the generation and maintenance of the geomagnetic field, and without that geomagnetic field there would be no life on the Earth's surface."

The research has been published in Science Magazine.



Contacts and sources: .
Australian National University




Citation:  Hrvoje Tkalčić, Thanh-Son Phạm. Shear properties of Earth’s inner core constrained by a detection of J waves in global correlation wavefield. Science, 2018; 362 (6412): 329 DOI: 10.1126/science.aau7649    .



Beamed Microwave Energy May Launch Space Vehicles


 The Air Force Office of Scientific Research (AFOSR) has awarded two College of Engineering faculty members, Michael M. Micci, professor of aerospace engineering, and Sven G. Bilén, head of the School of Engineering Design, Technology, and Professional Programs and professor of engineering design, aerospace engineering and electrical engineering, funding totaling more than $823,000 for a three-year program to develop and use a facility to study the use of beamed microwave energy to launch space vehicles off the surface of Earth.
An experimental rocket engine to collect beamed microwave energy to heat propellants to plasma temperatures.

Credit: Penn State

The funding consists of two separate awards, with the first being $396,865 provided by the Defense University Research Instrumentation Program, which funds large-scale equipment acquisition by universities. This award will be used to acquire a five-foot diameter by eight-foot-long high-vacuum chamber to simulate both high altitudes and the space environment. The funding also provides for the acquisition of a high-power microwave source and related microwave and optical diagnostic equipment.

The second award of $426,913 from AFOSR is to utilize the facility to examine the feasibility of beaming microwave power to a space vehicle, where it is focused to heat either an on-board propellant or ingested surrounding air to create a plasma with temperatures higher than can be achieved with current chemical propulsion methods. Because of the higher propellant temperatures, more thrust can be achieved for the same flow rate of propellant. Since the microwave source is located on the ground and not on the space vehicle, it is powered by the commercial electrical grid, allowing a large amount of energy to be transmitted to the space vehicle without any weight penalty for the vehicle.

Michael M. Micci (left), professor of aerospace engineering, and Sven G. Bilén (right), head of the School of Engineering Design, Technology, and Professional Programs and professor of engineering design, aerospace engineering and electrical engineering, have been awarded more than $823,000 from AFOSR for a three-year program to develop and use a facility to study the use of beamed microwave energy to launch space vehicles off the surface of Earth.

Credit: Penn State

Experiments will also be conducted at the Air Force Research Laboratory in Albuquerque, New Mexico, where a multimillion-dollar 100-kilowatt, 95-gigahertz microwave source is located.

“If this concept proves viable, it has the potential to drastically reduce the cost of placing spacecraft into Earth’s orbit, something which has both governmental and commercial applications,” said Micci.

A reverse of the concept is shown here:  an array of solar collectors once envisioned by NASA as part of a Lunar Solar Power System. This field would collect the energy from sunlight and convert it into electricity. This power would then be converted into microwave beams directed toward the Earth. Large rectennas on the Earth would collect this energy and direct it into existing and new distribution grids.
Credit: NASA


Contacts and sources: 
Penn State College of Engineering

Saturday, October 20, 2018

Fish Teeth Document over 2,000 Years of Trade between Canaan and Egypt beginning 3500 Years Ago


Gilthead sea bream were caught in the Bardawil lagoon on a large scale and transported as dried fish to the area in which Israel is located today

Some 3,500 years ago, there was already a brisk trade in fish on the shores of the southeastern Mediterranean Sea. This conclusion follows from the analysis of 100 fish teeth that were found at various archaeological sites in what is now Israel.

Jaw with a durophagous dentition consisting of teeth with thick enamel of the gilthead sea bream (Sparus aurata): The large molariform tooth was used for oxygen isotope analysis and to estimate the size of the fish.
Credit: photo/©: Guy Sisma-Ventura, Israel

The saltwater fish from which these teeth originated is the gilthead sea bream, which is also known as the dorade. It was caught in the Bardawil lagoon on the northern Sinai coast and then transported from Egypt to sites in the southern Levant. This fish transport persisted for about 2,000 years, beginning in the Late Bronze Age and continuing into the early Byzantine Period, roughly 300 to 600 AD. 

"Our examination of the teeth revealed that the sea bream must have come from a very saline waterbody, containing much more salt than the water in the Mediterranean Sea," said Professor Thomas Tütken of Johannes Gutenberg University Mainz (JGU). The geoscientist participated in the study together with colleagues from Israel and Göttingen. The Bardawil lagoon formed 4,000 years ago, when the sea level finally stabilized after the end of the last Ice Age. The lagoon was fished intensively and was the point of origin of an extensive fish trade.

As demonstrated by archaeological finds, fishing was an important economic factor for many ancient cultures. In the southern Levant, the gilthead sea bream with the scientific name of Sparus aurata was already being fished by local coastal fishermen 50,000 years ago. More exotic fish, such as the Nile perch, were already being traded between Egypt and Canaan over 5,000 years ago. However, the current study shows the extent to which the trade between the neighbors increased in the Late Bronze Age and continued for 2,000 years into the Byzantine Period.

 "The Bardawil lagoon was apparently a major source of fish and the starting point for the fish deliveries to Canaan, today's Israel, even though the sea bream could have been caught there locally," stated co-author Professor Andreas Pack from the University of Göttingen.

Fish teeth document over 2,000 years of trade

Gilthead sea bream are a food fish that primarily feed on crabs and mussels. They have a durophagous dentition with button-shaped teeth that enable them to crush the shells to get at the flesh. For the purposes of the study, 100 large shell-cracking teeth of gilthead sea bream were examined. 

Large, shell-cracking molariform tooth of the gilthead sea bream found in Bronze Age layers in today's Israel
photo/©: Guy Sisma-Ventura, Israel

The teeth originate from 12 archeological sites in the southern Levant, some of which lie inland, some on the coast, and cover a time period from the Neolithic to the Byzantine Period. One approach of the researchers was to analyze the content of the oxygen isotopes 18O and 16O in the tooth enamel of the sea bream. The ratio of 18O to 16O provides information on the evaporation rate and thus on the salt content of the surrounding water in which the fish lived. In addition, the researchers were able to estimate the body size of the fish on the basis of the size of the shell-cracking teeth.

Map of the archeological sites in Israel where the sea bream teeth analyzed were found. Also shown is the Bardawil lagoon on the Sinai Peninsula, from which the sea bream remains dating back as far as the Late Bronze Age primarily originated

Ill./©: Thomas Tütken

The analyses showed that some of the gilthead sea bream originated from the southeastern Mediterranean but that roughly three out of every four must have lived in a very saline body of water. The only water that comes into question in the locality is that of the Bardawil lagoon, the hypersaline water of which has a salt content of 3.9 to 7.4 percent, providing the perfect environment for the growth of sea bream. The Bardawil lagoon on the Sinai coast is approximately 30 kilometers long, 14 kilometers wide, and has a maximum depth of 3 meters. It is separated from the Mediterranean by a narrow sand bar.

"There was a mainland route from there to Canaan, but the fish were probably first dried and then transported by sea," added Tütken. Even back then, sea bream were probably a very popular food fish, although it is impossible to estimate actual quantities consumed. However, it became apparent that the fish traded from the period of the Late Bronze Age were significantly smaller than in the previous era.

According to the researchers, this reduction in body size is a sign of an increase in the intensity of fishing that led to a depletion of stocks, which is to be witnessed also in modern times. "It would seem that fishing and the trade of fish expanded significantly, in fact to such a degree that the fish did not have the chance to grow as large," continued Tütken, pointing out that this was an early form of the systematic commercial exploitation of fish, a type of proto-aquaculture, which persisted for some 2,000 years.

Geoscientist Professor Thomas Tütken of the Department of Applied and Analytical Paleontology at JGU received an ERC Consolidator Grant from the European Research Council in 2016. The current research study was undertaken jointly with another ERC project of his colleagues in Israel. Dr. Guy Sisma-Ventura, who currently works at the Israel Oceanographic and Limnological Research (IOLR), stayed for a month in Mainz, where the researchers performed the major part of the oxygen isotope analyses.



Contacts and sources:     .
 Professor Thomas Tütken / Guy Sisma-Ventura
Johannes Gutenberg University Mainz (JGU)

Citation: G. Sisma-Ventura et al., Tooth oxygen isotopes reveal Late Bronze Age origin of Mediterranean fish aquaculture and trade, Scientific Reports, 20 September 2018,
DOI:10.1038/s41598-018-32468-1   .



New Study Finds Clues To How Birds Began To Fly

For the first time, researchers have measured what is known as the ground effect of flying animals - and it turns out that they save a lot more energy by flying close to the ground than previously believed. The study from Lund University in Sweden supports one of the theories on how birds began to fly.

Our measurements show that the ground effect saves animals twice as much energy as models have suggested.”, says Christoffer Johansson, biologist at Lund University.

For the first time, Christoffer Johansson, together with colleagues Anders Hedenström at Lund University and Lasse Jakobsen at the University of Southern Denmark, have successfully managed to measure the ground effect when Daubenton’s bats fly in a wind tunnel.

Daubenton's bat 
Daubenton's bat (Photo: Jens Rydell)
Photo: Jens Rydell

In short, the ground effect means that a surface, ground or water, acts as an aerodynamic mirror that increases the air pressure under the wings – it costs less to generate lift. The ground effect is achieved within one wingspan of the surface, and the effect decreases exponentially with distance to the surface. An even surface, e.g. a calm lake where bats and birds catch insects or drink while they fly, provides optimal conditions. The new study also shows that animals use even less energy if they flap their wings rather than gliding near the ground.



Although the study was performed on bats, it has implications for birds and insects. One theory of how animals developed the art of flying is that they threw themselves between branches and trees. Another theory is that flying began on the ground. By running and jumping, proto-wings could have allowed the animals to run faster and jump higher and eventually flight evolved, a theory commonly known as the “ground up” theory. The corresponding theory behind today’s flying insects is that they moved on the water surface and eventually evolved wings as a means of propelling themselves across the surface.

“This is obviously speculation, but if flapping animals save more energy than we previously believed by flying close to the ground, then the ground up theory becomes more probable, i.e. that the animals began to fly by first running and jumping on the ground with flapping precursors to wings.”, says Christoffer Johansson.

 

Contacts and sources: .
Christoffer Johansson, senior lecturer
 Lund University

Citation: .Flight in Ground Effect Dramatically Reduces Aerodynamic Costs in Bats



Dandelions Reveal Newly Found Form of Flight



The extraordinary flying ability of dandelion seeds is possible thanks to a form of flight that has not been seen before in nature, research has revealed.

The discovery confirms the common plant among the natural world’s best fliers.

It shows that movement of air around and within its parachute-shaped bundle of bristles enables seeds to travel great distances – often a kilometer or more, kept afloat entirely by wind power.

Blowing On A Dandelion (3562861685).jpg
Credit:

Improved drag

Researchers from the University carried out experiments to better understand why dandelion seeds fly so well, despite their parachute structure being largely made up of empty space.

Their study revealed that a ring-shaped air bubble forms as air moves through the bristles, enhancing the drag that slows each seed’s descent to the ground.

Stabilizing flow

This newly found form of air bubble – which the scientists have named the separated vortex ring – is physically detached from the bristles and is stabilized by air flowing through it.

The amount of air flowing through, which is critical for keeping the bubble stable and directly above the seed in flight, is precisely controlled by the spacing of the bristles.

This flight mechanism of the bristly parachute underpins the seeds’ steady flight.

It is four times more efficient than what is possible with conventional parachute design, according to the research.

Design inspiration

Researchers suggest that the dandelion’s porous parachute might inspire the development of small-scale drones that require little or no power consumption.

Such drones could be useful for remote sensing or air pollution monitoring.

The study, published in Nature, was funded by the Leverhulme Trust and the Royal Society.


Taking a closer look at the ingenious structures in nature – like the dandelion’s parachute – can reveal novel insights. We found a natural solution for flight that minimizes the material and energy costs, which can be applied to engineering of sustainable technology.Dr Cathal CumminsSchools of Biological Sciences and Engineering





Contacts and sources:     .
University of Edinburgh

Citation: A separated vortex ring underlies the flight of the dandelion.
Cathal Cummins, Madeleine Seale, Alice Macente, Daniele Certini, Enrico Mastropaolo, Ignazio Maria Viola, Naomi Nakayama.Nature, 2018; 562 (7727): 414 DOI: 10.1038/s41586-018-0604-2    .



New Way to Unmask Blood Doping in Athletes



A Duke University research team has found a way to help sporting officials detect whether an athlete's blood has been doped by an infusion of their own stored blood.

While tests have been developed to detect two of the three most common methods of dramatically boosting the oxygen-carrying capacity of a competitor's blood, so-called "autologous" or self-transfusions have been impossible to detect.

An autologous transfusion takes some of the athlete's blood out well before the competition, sorts out just the red blood cells, and then transfuses those cells back into the athlete right before competition to enhance the blood's ability to carry oxygen, the essential fuel of muscle performance.

Red blood cells ferry oxygen to tissues, providing fuel for muscular activity. Unscrupulous athletes have been able to 'dope' their blood by enriching their supply of red blood cells. But a new test of microRNA can tell old cells from new ones.

Credit: Bruce Blausen via Wikimedia Commons

The best detection method the World Anti-Doping Agency (WADA) has used to date is the "Athlete Passport," which compares a pre-competition blood sample to one taken at competition to see if there are 'significant' changes in biochemistry.

"The difficulty has been that the tests they have couldn't tell the difference between a young blood cell and an old one," said Jen-Tsan "Ashley" Chi, M.D., Ph.D., who led this WADA-funded research in his lab at Duke's Center for Genomic and Computational Biology.

Blood banks in the U.S. consider 42 days the outer limit of how long a unit of red blood cells should be stored because of biochemical changes that could harm recipients. The amount of energy-providing ATP drops and oxygen-binding hemoglobin declines as well. But those changes have not been precise enough to detect an autologous transfusion.

What Chi and his colleagues looked at in the red blood cells is nucleic acids, specifically RNA. Red blood cells were long thought to lack nucleic acids because they don't carry a nucleus, where one would normally find DNA. But it turns out they contain an abundant and diverse population of RNAs. Among these are some short RNA pieces called microRNAs (miRNA) which generally act to control the production of proteins in a cell.

The researchers drew three units of blood from volunteers and processed them to remove virtually all of the white blood cells and about 80 percent of the plasma, leaving behind a relatively purified sample of red blood cells, just as an autologous transfusion would require.

Then Jennifer Doss, a former Duke graduate student, and other lab members extracted and analyzed RNA samples taken from the cells at eight time intervals, from 1 day to 42 days. Changes in the RNA associated with storage became apparent as they compared the later samples to the Day 1 sample.

Two types of miRNA increased in number during storage and two declined, said graduate student Wen-Hsuan Yang, who performed the biochemistry experiments. One of the forms that declined, called miR-70, had the most dramatic and consistent changes.

With further testing, the researchers isolated the likely source of this 18-nucleotide fragment of RNA. It seems to result as a byproduct from a larger RNA that is cut by enzymes during storage, and it happens in a very precise, predictable way.

"This increase in miR-720 is significant enough and consistent enough that it could be used as a biomarker for detecting stored red blood cells," Chi said.

He said further research is focused on understanding why the enzyme that produces miR-720 is active in stored cells and what it might be doing as it breaks a larger RNA apart.

In addition to Chi, Yang and Doss, the research team included Katelyn Walzer, Shannon McNulty, Jianli Wu and John Roback.

This research, which appears Oct. 18 in the British Journal of Haematology, was supported by the World Anti-Doping Agency (WADA), the Partnership for Clean Competition, the National Institutes of Health, the National Science Foundation, the government of Taiwan and Duke University.




Contacts and sources: .
Karl Leif Bates
Duke University


Citation: "Angiogenin-mediated tRNA Cleavage as a Novel Feature of Stored Red Blood Cells," Wen-Hsuan Yang, Jennifer Doss, Katelyn Walzer, Shannon McNulty, Jianli Wu, John Roback and Jen-Tsan Chi. British Journal of Haemotology, Oct. 18, 2018. DOI: 10.1111/bjh.15605 .



Youth Violence Lower in Countries with Complete Ban on Corporal Punishment


A study published today in the BMJ Open shows that in countries where there is a complete ban on all corporal punishment of children there is less fighting among young people. 

There was 31% less physical fighting in young men and 42% less physical fighting in young women in countries where corporal punishment was banned in all settings, compared with those where corporal punishment was permitted both at school and at home. In countries where there was a partial ban on corporal punishment (such as in Canada, the US and the UK where corporal punishment not banned in at home), the level of violence in young men was similar to that in countries with no bans, though the level of violence in women was lower (at 56%).
Credit; McGill University

Previous studies have shown a clear relationship between childhood spanking and a host of negative outcomes later on ranging from aggression to mental health problems. In this case, however, the researchers caution that they see an association rather than a causal relationship between legal bans on corporal punishment and violence in youth.

“All we can say, at this point, is that countries that prohibit the use of corporal punishment are less violent for children to grow up in than countries that do not,” says Frank Elgar, of McGill’s Institute for Health and Social Policy, the lead author on the study. “At this point we are simply taking a stratospheric view of the issue at an international level and note the correlation. To be able to show an effect of bans on youth violence, we will need to go back in 4-8 years after more data has been collected. We will also need to ask children and youth more questions about what’s going on at home, something that researchers have typically been shy to do.”

Takeaways

Frequent fighting was generally more common in young men (close to 10%) than in young women (about 3%)

Fighting varied widely from one country to the next ranging from under 1% in Costa Rican young women to close to 35% in Samoan young men

The researchers found that the associations between corporal punishment and youth violence remained, even after taking potential confounders were taken into account such as per capita income, murder rates and parent education programmes to prevent child maltreatment.

How the research was done

The researchers used data gathered from adolescents in 88 countries around the world by the World Health Organization Health Behaviour in School Aged Children (HBSC) study and the Global School-Based Health Survey (GSHS). The youth responded to survey questions at varying ages about how often they got into fights. The researchers correlated this information with data from each country about the prohibition of corporal punishment. Countries were grouped into: those with a complete ban on the use of corporal punishment at home and in schools (30 countries, the majority of which are in Europe, as well as a smaller number in Latin America, Asia and Africa); those with a ban in schools but not in the home (38 countries, among them China, the US, UK, and Canada), and those with no ban on corporal punishment (20 countries, ranging from Myanmar to the Solomon Islands).


The research was funded by the Canadian Institutes for Health Research (CIHR), the Social Sciences and Humanities Research Council (SSHRC), and the Canada Research Chairs Program.


Contacts and sources: .
Frank Elgar, Institute for Health and Social Policy, McGill University
Katherine Gombay, McGill University


Citation: Corporal punishment bans and physical fighting in adolescents: an ecological study of 88 countries.
Elgar FJ, Donnelly PD, Michaelson V, et al. BMJ Open, 2018 DOI: 10.1136/bmjopen-2018-021616   .



First Proof of Quantum Computer Advantage; New Quantum Circuit Developed


Quantum computers promise to revolutionize the future of computing. A scientist from the Technical University of Munich (TUM) together with his colleagues from the University of Waterloo and from IBM have now demonstrated for the first time that quantum computers do indeed offer advantages over conventional computers.

For many years, quantum computers were not much more than an idea. Today, companies, governments and intelligence agencies are investing in the development of quantum technology. Robert König, professor for the theory of complex quantum systems at the TUM, in collaboration with David Gosset from the Institute for Quantum Computing at the University of Waterloo and Sergey Bravyi from IBM, has now placed a cornerstone in this promising field.

Layout of IBM's four superconducting quantum bit device. 
Image: IBM Research, https://www.flickr.com/photos/ibm_research_zurich/16662697764/in/album-72157663611181258/

WHY SHOULD QUANTUM COMPUTERS BE FASTER?

Conventional computers obey the laws of classical physics. They rely on the binary numbers 0 and 1. These numbers are stored and used for mathematical operations. In conventional memory units, each bit – the smallest unit of information – is represented by a microscopic dot on a microchip. Each of these dots can hold a charge that determines whether the bit is set to 1 or 0.

In a quantum computer, however, a bit can be both 0 and 1 at the same time. This is because the laws of quantum physics allow electrons to be in multiple places at one time. Quantum bits, or qubits, thus exist in multiple overlapping states. This so-called superposition allows quantum computers to perform operations on many values in one fell swoop whereas a single conventional computer typically must execute these operations sequentially. The promise of quantum computing lies in the ability to solve certain problems significantly faster.

FROM CONJECTURE TO PROOF

König and his colleagues have now conclusively demonstrated the advantage of quantum computers. To this end, they developed a quantum circuit that can solve a specific "difficult" algebraic problem. The new circuit has a simple structure: it only performs a fixed number of operations on each qubit. Such a circuit is referred to as having a constant depth. In their work, the researchers prove that the problem at hand cannot be solved using classical constant-depth circuits. They furthermore answer the question of why the quantum algorithm beats any comparable classical circuit: The quantum algorithm exploits the non-locality of quantum physics.

Prior to this work, the advantage of quantum computers had neither been proven nor experimentally demonstrated – notwithstanding that evidence pointed in this direction. One example is Shor’s quantum algorithm, which efficiently solves the problem of prime factorization. However, it is merely a complexity-theoretic conjecture that this problem cannot be efficiently solved without quantum computers. It is also conceivable that the right approach has simply not yet been found for classical computers.

A STEP ON THE ROAD TO QUANTUM COMPUTING

Robert König considers the new results primarily as a contribution to complexity theory. "Our result shows that quantum information processing really does provide benefits – without having to rely on unproven complexity-theoretic conjectures," he says. Beyond this, the work provides new milestones on the road to quantum computers. Because of its simple structure, the new quantum circuit is a candidate for a near-term experimental realization of quantum algorithms.

Contacts and sources:
Prof. Dr. Robert König .\
Technical University of Munich (TUM)


Citation: Quantum advantage with shallow circuits
Sergey Bravyi, David Gosset, Robert König. . Science, 2018; 362 (6412): 308 DOI: 10.1126/science.aar3106



Thursday, October 18, 2018

PrinTracker Can Analyze Machine "Fingerprints" and Help Identify 3D Printed Guns and Counterfeit Products Origins



- Like fingerprints, no 3D printer is exactly the same.

That's the takeaway from a new University at Buffalo-led study that describes what's believed to be the first accurate method for tracing a 3D-printed object to the machine it came from.

The advancement, which the research team calls "PrinTracker," could ultimately help law enforcement and intelligence agencies track the origin of 3D-printed guns, counterfeit products and other goods.

"3D printing has many wonderful uses, but it's also a counterfeiter's dream. Even more concerning, it has the potential to make firearms more readily available to people who are not allowed to possess them," says the study's lead author Wenyao Xu, PhD, associate professor of computer science and engineering in UB's School of Engineering and Applied Sciences.

Photo illustration of how the technology works.
illustration of how the 3D printer fingerprinting technology works
Credit: Wenyao Xu, University at Buffalo

The study will be presented in Toronto at the Association for Computing Machinery's Conference on Computer and Communications Security, which runs from Oct. 15-19. It includes coauthors from Rutgers University and Northeastern University.

To understand the method, it's helpful to know how 3D printers work. Like a common inkjet printer, 3D printers move back-and-forth while "printing" an object. Instead of ink, a nozzle discharges a filament, such as plastic, in layers until a three-dimensional object forms.

Each layer of a 3D-printed object contains tiny wrinkles -- usually measured in submillimeters -- called in-fill patterns. These patterns are supposed to be uniform. However, the printer's model type, filament, nozzle size and other factors cause slight imperfections in the patterns. The result is an object that does not match its design plan.

For example, the printer is ordered to create an object with half-millimeter in-fill patterns. But the actual object has patterns that vary 5 to 10 percent from the design plan. Like a fingerprint to a person, these patterns are unique and repeatable. As a result, they can be traced back to the 3D printer.

"3D printers are built to be the same. But there are slight variations in their hardware created during the manufacturing process that lead to unique, inevitable and unchangeable patterns in every object they print," Xu says.

To test PrinTracker, the research team created five door keys each from 14 common 3D printers -- 10 fused deposition modeling (FDM) printers and four stereolithography (SLA) printers.

With a common scanner, the researchers created digital images of each key. From there, they enhanced and filtered each image, identifying elements of the in-fill pattern. They then developed an algorithm to align and calculate the variations of each key to verify the authenticity of the fingerprint.

Having created a fingerprint database of the 14 3D printers, the researchers were able to match the key to its printer 99.8 percent of the time. They ran a separate series of tests 10 months later to determine if additional use of the printers would affect PrinTracker's ability to match objects to their machine of origin. The results were the same.

The team also ran experiments involving keys damaged in various ways to obscure their identity. PrinTracker was 92 percent accurate in these tests.

Xu likens the technology to the ability to identify the source of paper documents, a practice used by law enforcement agencies, printer companies and other organizations for decades. While the experiments did not involve counterfeit goods or firearms, Xu says PrinTracker can be used to trace any 3D-printed object to its printer.

"We've demonstrated that PrinTracker is an effective, robust and reliable way that law enforcement agencies, as well as businesses concerned about intellectual property, can trace the origin of 3D-printed goods," Xu says.


Contacts and sources:     .
Cory Nealon
University at Buffalo
     .



New Solar Heat to Electricity Cheap Enough to Compete with Fossil Fuels

Solar power accounts for less than 2 percent of U.S. electricity but could make up more than that if the cost of electricity generation and energy storage for use on cloudy days and at nighttime were cheaper.

A Purdue University-led team developed a new material and manufacturing process that would make one way to use solar power – as heat energy – more efficient in generating electricity.

The innovation is an important step for putting solar heat-to-electricity generation in direct cost competition with fossil fuels, which generate more than 60 percent of electricity in the U.S.

Credit: Purdue University

“Storing solar energy as heat can already be cheaper than storing energy via batteries, so the next step is reducing the cost of generating electricity from the sun's heat with the added benefit of zero greenhouse gas emissions,” said Kenneth Sandhage, Purdue’s Reilly Professor of Materials Engineering.

The research, which was done at Purdue in collaboration with the Georgia Institute of Technology, the University of Wisconsin-Madison and Oak Ridge National Laboratory, published in the journal Nature
S
A recent development would make electricity generation from the sun's heat more efficient, by using ceramic-metal plates for heat transfer at higher temperatures and at elevated pressures.
 Purdue University illustration/Raymond Hassan

This work aligns with Purdue's Giant Leaps celebration, acknowledging the university’s global advancements made for a sustainable economy and planet as part of Purdue’s 150th anniversary. This is one of the four themes of the yearlong celebration’s Ideas Festival, designed to showcase Purdue as an intellectual center solving real-world issues.

Solar power doesn't only generate electricity via panels in farms or on rooftops. Another option is concentrated power plants that run on heat energy.

Concentrated solar power plants convert solar energy into electricity by using mirrors or lenses to concentrate a lot of light onto a small area, which generates heat that is transferred to a molten salt. Heat from the molten salt is then transferred to a "working" fluid, supercritical carbon dioxide, that expands and works to spin a turbine for generating electricity.

To make solar-powered electricity cheaper, the turbine engine would need to generate even more electricity for the same amount of heat, which means the engine needs to run hotter.

The problem is that heat exchangers, which transfer heat from the hot molten salt to the working fluid, are currently made of stainless steel or nickel-based alloys that get too soft at the desired higher temperatures and at the elevated pressure of supercritical carbon dioxide.

Inspired by the materials his group had previously combined to make "composite" materials that can handle high heat and pressure for applications like solid-fuel rocket nozzles, Sandhage worked with Asegun Henry, now at the Massachusetts Institute of Technology, to conceive of a similar composite for more robust heat exchangers.

Two materials showed promise together as a composite: The ceramic zirconium carbide, and the metal tungsten.

Purdue researchers created plates of the ceramic-metal composite. The plates host customizable channels for tailoring the exchange of heat, based on simulations of the channels conducted at Georgia Tech by Devesh Ranjan's team.

Mechanical tests by Edgar Lara-Curzio’s team at Oak Ridge National Laboratory and corrosion tests by Mark Anderson’s team at Wisconsin-Madison helped show that this new composite material could be tailored to successfully withstand the higher temperature, high-pressure supercritical carbon dioxide needed for generating electricity more efficiently than today’s heat exchangers.

An economic analysis by Georgia Tech and Purdue researchers also showed that the scaled-up manufacturing of these heat exchangers could be conducted at comparable or lower cost than for stainless steel or nickel alloy-based ones.

“Ultimately, with continued development, this technology would allow for large-scale penetration of renewable solar energy into the electricity grid,” Sandhage said. “This would mean dramatic reductions in man-made carbon dioxide emissions from electricity production.”

A patent application has been filed for this advancement. The work is supported by the U.S. Department of Energy, which has also recently awarded additional funding for further development and scaling up the technology.

Contacts and sources: 
Kayla Wiles / Kenneth Sandhage
Purdue University


Citation: Ceramic–metal composites for heat exchangers in concentrated solar power plants
M. Caccia, M. Tabandeh-Khorshid, G. Itskos, A. R. Strayer, A. S. Caldwell, S. Pidaparti, S. Singnisai, A. D. Rohskopf, A. M. Schroeder, D. Jarrahbashi, T. Kang, S. Sahoo, N. R. Kadasala, A. Marquez-Rossy, M. H. Anderson, E. Lara-Curzio, D. Ranjan, A. Henry, K. H. Sandhage. . Nature, 2018; 562 (7727): 406 DOI: 10.1038/s41586-018-0593-1     .




Cuttlefish Camouflage: Wearing Thoughts on the Skin and Biological Invisibility


Computational image analysis of behaving cuttlefish reveals principles of control and development of a biological invisibility cloak

The unique ability of cuttlefish, squid and octopuses to hide by imitating the colors and texture of their environment has fascinated natural scientists since the time of Aristotle. Uniquely among all animals, these mollusks control their appearance by the direct action of neurons onto expandable pixels, numbered in millions, located in their skin. Scientists at the Max Planck Institute for Brain Research and the Frankfurt Institute for Advanced Studies/Goethe University used this neuron-pixel correspondence to peer into the brain of cuttlefish, inferring the putative structure of control networks through analysis of skin pattern dynamics.


A common cuttlefish (Sepia officinalis)
Credit: © MPI for Brain Research / Stephan Junek

Cuttlefish, squid and octopus are a group of marine mollusks called coleoid cephalopods that once included ammonites, today only known as spiral fossils of the Cretaceous era. Modern coleoid cephalopods lost their external shells about 150 million years ago and took up an increasingly active predatory lifestyle. This development was accompanied by a massive increase in the size of their brains: modern cuttlefish and octopus have the largest brains (relative to body size) among invertebrates with a size comparable to that of reptiles and some mammals. They use these large brains to perform a range of intelligent behaviors, including the singular ability to change their skin pattern to camouflage, or hide, in their surroundings.

Cephalopods control camouflage by the direct action of their brain onto specialized skin cells called chromatophores, that act as biological color “pixels” on a soft skin display. Cuttlefish possess up to millions of chromatophores, each of which can be expanded and contracted to produce local changes in skin contrast. By controlling these chromatophores, cuttlefish can transform their appearance in a fraction of a second. They use camouflage to hunt, to avoid predators, but also to communicate.

To camouflage, cuttlefish do not match their local environment pixel by pixel. Instead, they seem to extract, through vision, a statistical approximation of their environment, and use these heuristics to select an adaptive camouflage out of a presumed large but finite repertoire of likely patterns, selected by evolution. The biological solutions to this statistical-matching problem are unknown. But because cuttlefish can solve it as soon as they hatch out of their egg, their solutions are probably innate, embedded in the cuttlefish brain and relatively simple. A team of scientists at the Max Planck Institute for Brain Research and at the Frankfurt Institute for Advanced Studies (FIAS)/Goethe University, led by MPI Director Gilles Laurent, developed techniques that begin to reveal those solutions.

Cuttlefish chromatophores are specialized cells containing an elastic sack of colored pigment granules. Each chromatophore is attached to minute radial muscles, themselves controlled by small numbers of motor neurons in the brain. When these motor neurons are activated, they cause the muscles to contract, expanding the chromatophore and displaying the pigment. When neural activity ceases, the muscles relax, the elastic pigment sack shrinks back, and the reflective underlying skin is revealed. Because single chromatophores receive input from small numbers of motor neurons, the expansion state of a chromatophore could provide an indirect measurement of motor neuron activity.

“We set out to measure the output of the brain simply and indirectly by imaging the pixels on the animal’s skin” says Laurent. Indeed, monitoring cuttlefish behavior with chromatophore resolution provided a unique opportunity to indirectly ‘image’ very large populations of neurons in freely behaving animals. Postdoc Sam Reiter from the Laurent Lab, the first author of this study, and his coauthors inferred motor neuron activity by analyzing the details of chromatophore co-fluctuations. In turn, by analyzing the co-variations of these inferred motor neurons, they could predict the structure of yet higher levels of control, ‘imaging’ increasingly more deeply into the cuttlefish brain through detailed statistical analysis of its chromatophore output.

Credit: © Nature

Cuttlefish: Wearing thoughts on the skin

A new technique is allowing researchers to study the inner workings of a cuttlefish brain by tracking colour changing cells in their skin. These cell are directly controlled by neurons extending from the brain. By monitoring the cells with high resolution cameras, researchers can track the activity tens of thousands of neurons at once for the first time.

Getting there took many years of hard work, some good insights and a few lucky breaks. A key requirement for success was to manage to track tens of thousands of individual chromatophores in parallel at 60 high-resolution images per second and to track every chromatophore from one image to the next, from one pattern to the next, from one week to the next, as the animal breathed, moved, changed appearance and grew, constantly inserting new chromatophores. One key insight was “realizing that the physical arrangement of chromatophores on the skin is irregular enough that it is locally unique, thus providing local fingerprints for image stitching” says Matthias Kaschube of FIAS/GU. By iterative and piecewise image comparison, it became possible to warp images such that all the chromatophores were properly aligned and trackable, even when their individual sizes differed —as occurs when skin patterns change— and even when new chromatophores had appeared —as happens from one day to the next as the animal grows. 

 
Credit: nature video
With insights such as this one, and aided by multiple supercomputers, Laurent’s team managed to meet their goal and with this, started peering into the brain of the animal and its camouflage control system. Along the way, they also made unexpected observations. For example, when an animal changes appearance, it changes in a very specific manner through a sequence of precisely determined intermediate patterns. This observation is important because it suggests internal constraints on pattern generation, thus revealing hidden aspects of the neural control circuits. They also found that chromatophores systematically change colors over time, and that the time necessary for this change is matched to the rate of production of new chromatophores as the animal grows, such that the relative fraction of each color remains constant. Finally, from observing this development they derived minimal rules that may explain skin morphogenesis in this and possibly all other species of coleoid cephalopods.

“This study opens up a large range of new questions and opportunities”, says Laurent. “Some of these concern texture perception and are relevant to the growing field of cognitive computational neuroscience; others help define the precise link between brain activity and behavior, a field called neuroethology; others yet help identify the cellular rules of development involved in tissue morphogenesis. Finally, this work opens a window into the brain of animals whose lineage split from ours over 540 million years ago. Cephalopod brains offer a unique opportunity to study the evolution of another form of intelligence, based on a history entirely independent of the vertebrate lineage for over half a billion years”.



Contacts and sources: 
Dr. Arjan Vink
Max-Planck-Gesellschaft


Citation: Elucidating the control and development of skin patterning in cuttlefish
Sam Reiter, Philipp Hülsdunk, Theodosia Woo, Marcel A. Lauterbach, Jessica S. Eberle, Leyla Anne Akay, Amber Longo, Jakob Meier-Credo, Friedrich Kretschmer, Julian D. Langer, Matthias Kaschube, Gilles Laurent. . Nature, 2018; 562 (7727): 361 DOI: 10.1038/s41586-018-0591-3    .



Smartphone Tool Measures Users Alertness on the Job

Our level of alertness rises and falls over the course of a workday, sometimes causing our energy to drop and our minds to wander just as we need to perform important tasks.
To help understand these patterns and improve productivity, Cornell researchers have developed a tool that tracks alertness by measuring pupil size, captured through a burst of photographs taken every time users unlock their smartphones.
“Since our alertness fluctuates, if we can find a pattern it will be very useful to manage and schedule our day,” said Vincent W.S. Tseng, a doctoral student in information science and lead author of “AlertnessScanner: What Do Your Pupils Tell About Your Alertness,” presented in September at the 20th International Conference on Human-Computer Interaction with Mobile Devices and Services.
Traditional methods of analyzing alertness tend to be cumbersome, often including devices that must be worn. Researchers in Cornell’s People-Aware Computing Lab, run by Tanzeem Choudhury, associate professor of information science and senior author on the study, wanted to create a way to measure alertness unobtrusively and continuously.
File:Pupil - eye.jpg

“Since people use their phones very frequently during the day, we were thinking we could use phones as an instrument to understand and measure their alertness,” Tseng said. “And since people’s eyes are affected by their alertness, we were thinking that when people are looking at their phones, we could use a moment to measure their alertness at that point.”
When people are alert, the sympathetic nervous system causes the pupils to dilate to make it easier to take in information. When they’re drowsy, the parasympathetic nervous system causes the pupils to contract.
The paper, co-authored with Saeed Abdullah, an assistant professor in the College of Information Sciences and Technology at Pennsylvania State University, and Cornell information science doctoral student Jean Costa, included two studies conducted over two years. The first study analyzed results from 15 users, who were prompted to take photos of themselves every three hours. Their smartphones needed to have their infrared filters removed to make it easier to detect the contours of the pupil and the iris, particularly for people with dark eyes. The participants were also asked to complete a sleep journal, reporting how many hours they’d slept each night, and to take a phone-based Psychomotor Vigilance Test (PVT) – a five-minute quiz to gauge their reaction time – six times a day.
The photos gave researchers a view of participants’ eyes that they then used to measure pupil size, making allowances for position and lighting, in order to predict a person’s reaction time. This was then compared to the results from the PVT.
The researchers found that the pupil-scanning reliably predicted alertness. But because asking people to remove their phones’ infrared filters was impractical, and prompting them to take photos of themselves throughout the day was too obtrusive, they conducted a second study a year later, when smartphone camera quality had improved enough that they no longer needed to remove the filters.
In that second study, eight participants were given smartphones with high-resolution front-facing cameras that took a burst of 30 photos in one second whenever the phones were unlocked. Users also completed the sleep journal and took the PVTs.
Though the two studies were difficult to compare because of their different methods, both showed that pupil scanning was a reliable means of predicting alertness. The second study, which took the photos passively in a burst, was deemed more practical because it required less work by the user, Tseng said.
Tseng said the AlertnessScanner could be particularly useful in health care, since medical professionals often work long hours doing intricate and important work. For example, clinicians typically look at devices during surgery, and a front-facing camera on the devices could track their alertness throughout procedures.
But understanding alertness patterns could be helpful to people in many kinds of workplaces, Tseng said.
“If you want to get something very important done, then probably you should execute this task while you’re at the peak of your alertness; when you’re in a valley of your alertness, you can do something like rote work,” he said. “You’ll also know the best time to take a break in order to allow your alertness or energy to go back up again.”
The research was partly supported by Intel and the Semiconductor Research Corporation, through a Circadian-Rhythm Aware Computing grant.



Contacts and sources:     .
Melanie Lefkowitz / Jeff Tyson
Cornell University

      .



Why The Enhanced Computing Power of The Human Brain



Neurons in the human brain receive electrical signals from thousands of other cells, and long neural extensions called dendrites play a critical role in incorporating all of that information so the cells can respond appropriately.

Using hard-to-obtain samples of human brain tissue, MIT neuroscientists have now discovered that human dendrites have different electrical properties from those of other species. Their studies reveal that electrical signals weaken more as they flow along human dendrites, resulting in a higher degree of electrical compartmentalization, meaning that small sections of dendrites can behave independently from the rest of the neuron.

These differences may contribute to the enhanced computing power of the human brain, the researchers say.

MIT neuroscientists can now record electrical activity from the dendrites of human neurons.
MIT neuroscientists can now record electrical activity from the dendrites of human neurons.
Image: Lou Beaulieu-Laroche and Mark Harnett

“It’s not just that humans are smart because we have more neurons and a larger cortex. From the bottom up, neurons behave differently,” says Mark Harnett, the Fred and Carole Middleton Career Development Assistant Professor of Brain and Cognitive Sciences. “In human neurons, there is more electrical compartmentalization, and that allows these units to be a little bit more independent, potentially leading to increased computational capabilities of single neurons.”

Harnett, who is also a member of MIT’s McGovern Institute for Brain Research, and Sydney Cash, an assistant professor of neurology at Harvard Medical School and Massachusetts General Hospital, are the senior authors of the study, which appears in the Oct. 18 issue of Cell. The paper’s lead author is Lou Beaulieu-Laroche, a graduate student in MIT’s Department of Brain and Cognitive Sciences.

Neural computation

Dendrites can be thought of as analogous to transistors in a computer, performing simple operations using electrical signals. Dendrites receive input from many other neurons and carry those signals to the cell body. If stimulated enough, a neuron fires an action potential — an electrical impulse that then stimulates other neurons. Large networks of these neurons communicate with each other to generate thoughts and behavior.

The structure of a single neuron often resembles a tree, with many branches bringing in information that arrives far from the cell body. Previous research has found that the strength of electrical signals arriving at the cell body depends, in part, on how far they travel along the dendrite to get there. As the signals propagate, they become weaker, so a signal that arrives far from the cell body has less of an impact than one that arrives near the cell body.

Dendrites in the cortex of the human brain are much longer than those in rats and most other species, because the human cortex has evolved to be much thicker than that of other species. In humans, the cortex makes up about 75 percent of the total brain volume, compared to about 30 percent in the rat brain.

Although the human cortex is two to three times thicker than that of rats, it maintains the same overall organization, consisting of six distinctive layers of neurons. Neurons from layer 5 have dendrites long enough to reach all the way to layer 1, meaning that human dendrites have had to elongate as the human brain has evolved, and electrical signals have to travel that much farther.

In the new study, the MIT team wanted to investigate how these length differences might affect dendrites’ electrical properties. They were able to compare electrical activity in rat and human dendrites, using small pieces of brain tissue removed from epilepsy patients undergoing surgical removal of part of the temporal lobe. In order to reach the diseased part of the brain, surgeons also have to take out a small chunk of the anterior temporal lobe.

With the help of MGH collaborators Cash, Matthew Frosch, Ziv Williams, and Emad Eskandar, Harnett’s lab was able to obtain samples of the anterior temporal lobe, each about the size of a fingernail.

Evidence suggests that the anterior temporal lobe is not affected by epilepsy, and the tissue appears normal when examined with neuropathological techniques, Harnett says. This part of the brain appears to be involved in a variety of functions, including language and visual processing, but is not critical to any one function; patients are able to function normally after it is removed.

Once the tissue was removed, the researchers placed it in a solution very similar to cerebrospinal fluid, with oxygen flowing through it. This allowed them to keep the tissue alive for up to 48 hours. During that time, they used a technique known as patch-clamp electrophysiology to measure how electrical signals travel along dendrites of pyramidal neurons, which are the most common type of excitatory neurons in the cortex.

These experiments were performed primarily by Beaulieu-Laroche. Harnett’s lab (and others) have previously done this kind of experiment in rodent dendrites, but his team is the first to analyze electrical properties of human dendrites.


Using hard-to-obtain samples of human brain tissue, McGovern and MGH researchers have now discovered that human dendrites have different electrical properties from those of other species. These differences may contribute to the enhanced computing power of the human brain, the researchers say.

Credit: MIT

Unique features

The researchers found that because human dendrites cover longer distances, a signal flowing along a human dendrite from layer 1 to the cell body in layer 5 is much weaker when it arrives than a signal flowing along a rat dendrite from layer 1 to layer 5.

They also showed that human and rat dendrites have the same number of ion channels, which regulate the current flow, but these channels occur at a lower density in human dendrites as a result of the dendrite elongation. They also developed a detailed biophysical model that shows that this density change can account for some of the differences in electrical activity seen between human and rat dendrites, Harnett says.

Nelson Spruston, senior director of scientific programs at the Howard Hughes Medical Institute Janelia Research Campus, described the researchers’ analysis of human dendrites as “a remarkable accomplishment.”

“These are the most carefully detailed measurements to date of the physiological properties of human neurons,” says Spruston, who was not involved in the research. “These kinds of experiments are very technically demanding, even in mice and rats, so from a technical perspective, it’s pretty amazing that they’ve done this in humans.”

The question remains, how do these differences affect human brainpower? Harnett’s hypothesis is that because of these differences, which allow more regions of a dendrite to influence the strength of an incoming signal, individual neurons can perform more complex computations on the information.

“If you have a cortical column that has a chunk of human or rodent cortex, you’re going to be able to accomplish more computations faster with the human architecture versus the rodent architecture,” he says.

There are many other differences between human neurons and those of other species, Harnett adds, making it difficult to tease out the effects of dendritic electrical properties. In future studies, he hopes to explore further the precise impact of these electrical properties, and how they interact with other unique features of human neurons to produce more computing power.

The research was funded by the National Sciences and Engineering Research Council of Canada, the Dana Foundation David Mahoney Neuroimaging Grant Program, and the National Institutes of Health.


Contacts and sources: 
Anne Trafton 
Massachusetts Institute of Technology


Newly Identified Piranha-Like Jurassic Era Denizen Now Earliest Known Flesh Eating Fish

Jurassic era fish is first known meat eater.

This image shows a new piranha-like fish from Jurassic seas with sharp, pointed teeth that probably fed on the fins of other fishes. From the time of dinosaurs and from the same deposits that contained Archaeopteryx, scientists recovered both this flesh-tearing fish and its scarred prey.

Credit: M. Ebert and T. Nohl


Researchers reporting in Current Biology on October 18 have described a remarkable new species of fish that lived in the sea about 150 million years ago in the time of the dinosaurs. The new species of bony fish had teeth like a piranha, which the researchers suggest they used as piranhas do: to bite off chunks of flesh from other fish.

As further support for that notion, the researchers also found the victims: other fish that had apparently been nibbled on in the same limestone deposits in South Germany (the quarry of Ettling in the Solnhofen region) where this piranha-like fish was found.

"We have other fish from the same locality with chunks missing from their fins," says David Bellwood of James Cook University, Australia. "This is an amazing parallel with modern piranhas, which feed predominantly not on flesh but the fins of other fishes. It's a remarkably smart move as fins regrow, a neat renewable resource. Feed on a fish and it is dead; nibble its fins and you have food for the future."

The newly described fish is part of the world famous collections in the Jura-Museum in Eichstätt. It comes from the same limestone deposits that contained Archaeopteryx.

Careful study of the fossilized specimen's well-preserved jaws revealed long, pointed teeth on the exterior of the vomer, a bone forming the roof of the mouth, and at the front of both upper and lower jaws. Additionally, there are triangular teeth with serrated cutting edges on the prearticular bones that lie along the side of the lower jaw.

The tooth pattern and shape, jaw morphology, and mechanics suggest a mouth equipped to slice flesh or fins, the international team of researchers report. The evidence points to the possibility that the early piranha-like fish may have exploited aggressive mimicry in a striking parallel to the feeding patterns of modern piranha.

This illustration shows an artist's reconstruction of the piranha-like fish.

Credit: The Jura-Museum, Eischstatt, Germany
"We were stunned that this fish had piranha-like teeth," says Martina Kölbl-Ebert of Jura-Museum Eichstätt (JME-SNSB). "It comes from a group of fishes (the pycnodontids) that are famous for their crushing teeth. It is like finding a sheep with a snarl like a wolf. But what was even more remarkable is that it was from the Jurassic. Fish as we know them, bony fishes, just did not bite flesh of other fishes at that time. Sharks have been able to bite out chunks of flesh but throughout history bony fishes have either fed on invertebrates or largely swallowed their prey whole. Biting chunks of flesh or fins was something that came much later."

Or, so it had seemed.

"The new finding represents the earliest record of a bony fish that bit bits off other fishes, and what's more it was doing it in the sea," Bellwood says, noting that today's piranhas all live in freshwater. "So when dinosaurs were walking the earth and small dinosaurs were trying to fly with the pterosaurs, fish were swimming around their feet tearing the fins or flesh off each other."

The researchers call the new find a "staggering example of evolutionary versatility and opportunism." With one of the world's best known and studied fossil deposits continuing to throw up such surprises, they intend to keep up the search for even more fascinating finds.

Funding for this project was provided by the Volkswagen Foundation, Deutsche Forschungsgemeinschaft, and the Australian Research Council.





Contacts and sources:     .
Carly Britton
Cell Press

Citation: Current Biology, Kölbl-Ebert et al.: "A Piranha-like Pycnodontiform Fish from the Late Jurassic" https://www.cell.com/current-biology/fulltext/S0960-9822(18)31208-9 



Superflares From Young Red Dwarf Stars Imperil Planets



The word "HAZMAT" describes substances that pose a risk to the environment, or even to life itself. Imagine the term being applied to entire planets, where violent flares from the host star may make worlds uninhabitable by affecting their atmospheres.

NASA's Hubble Space Telescope is observing such stars through a large program called HAZMAT -- Habitable Zones and M dwarf Activity across Time.

"M dwarf" is the astronomical term for a red dwarf star -- the smallest, most abundant and longest-lived type of star in our galaxy. The HAZMAT program is an ultraviolet survey of red dwarfs at three different ages: young, intermediate, and old.

Violent outbursts of seething gas from young red dwarf stars may make conditions uninhabitable on fledgling planets. In this artist's rendering, an active, young red dwarf (right) is stripping the atmosphere from an orbiting planet (left). Scientists found that flares from the youngest red dwarfs they surveyed — approximately 40 million years old — are 100 to 1,000 times more energetic than when the stars are older. They also detected one of the most intense stellar flares ever observed in ultraviolet light — more energetic than the most powerful flare ever recorded from our Sun.
artist's sketch of red dwarf and steaming planet
Credits: NASA, ESA and D. Player (STScI)

Stellar flares from red dwarfs are particularly bright in ultraviolet wavelengths, compared with Sun-like stars. Hubble's ultraviolet sensitivity makes the telescope very valuable for observing these flares. The flares are believed to be powered by intense magnetic fields that get tangled by the roiling motions of the stellar atmosphere. When the tangling gets too intense, the fields break and reconnect, unleashing tremendous amounts of energy.

The team has found that the flares from the youngest red dwarfs they surveyed -- just about 40 million years old -- are 100 to 1,000 times more energetic than when the stars are older. This younger age is when terrestrial planets are forming around their stars.

Approximately three-quarters of the stars in our galaxy are red dwarfs. Most of the galaxy's "habitable-zone" planets -- planets orbiting their stars at a distance where temperatures are moderate enough for liquid water to exist on their surface -- likely orbit red dwarfs. In fact, the nearest star to our Sun, a red dwarf named Proxima Centauri, has an Earth-size planet in its habitable zone.

However, young red dwarfs are active stars, producing ultraviolet flares that blast out so much energy that they could influence atmospheric chemistry and possibly strip off the atmospheres of these fledgling planets.

"The goal of the HAZMAT program is to help understand the habitability of planets around low-mass stars," explained Arizona State University's Evgenya Shkolnik, the program's principal investigator. "These low-mass stars are critically important in understanding planetary atmospheres."

The results of the first part of this Hubble program are being published in The Astrophysical Journal. This study examines the flare frequency of 12 young red dwarfs. "Getting these data on the young stars has been especially important, because the difference in their flare activity is quite large as compared to older stars," said Arizona State University's Parke Loyd, the first author on this paper.

The observing program detected one of the most intense stellar flares ever observed in ultraviolet light. Dubbed the "Hazflare," this event was more energetic than the most powerful flare from our Sun ever recorded.

"With the Sun, we have a hundred years of good observations," Loyd said. "And in that time, we've seen one, maybe two, flares that have an energy approaching that of the Hazflare. In a little less than a day's worth of Hubble observations of these young stars, we caught the Hazflare, which means that we're looking at superflares happening every day or even a few times a day."

Could super-flares of such frequency and intensity bathe young planets in so much ultraviolet radiation that they forever doom chances of habitability? According to Loyd, "Flares like we observed have the capacity to strip away the atmosphere from a planet. But that doesn't necessarily mean doom and gloom for life on the planet. It just might be different life than we imagine. Or there might be other processes that could replenish the atmosphere of the planet. It's certainly a harsh environment, but I would hesitate to say that it is a sterile environment."

The next part of the HAZMAT study will be to study intermediate-aged red dwarfs that are 650 million years old. Then the oldest red dwarfs will be analyzed and compared with the young and intermediate stars to understand the evolution of the ultraviolet radiation environment of low-mass planets around these low-mass stars.


The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, in Washington, D.C.




Contacts and sources:
Ann Jenkins / Ray Villard
Space Telescope Science Institute, Baltimore, Maryland

Evgenya Shkolnik  / Parke Loyd
Arizona State University, Tempe, Arizona


Citation:




Scientific Research Will Help to Understand the Origin of Life in the Universe



Scientists from Samara University and several universities in the USA have proposed and experimentally confirmed new fundamental chemical mechanisms for the synthesis of polycyclic aromatic hydrocarbons (PAHs).

Until now, in the scientific community there has been the prevailing view that thermal processes associated exclusively with the combustion and high-temperature processing of organic raw materials such as oil, coal, wood, garbage, food, tobacco underpin the formation of PAHs. However, the scientists from Samara University, together with their colleagues from the University of Hawaii, Florida International University, and Lawrence Berkeley National Laboratory proved that the chemical synthesis of PAHs can occur at very low temperatures, namely -183 C.

The described processes make it possible to understand how complex molecules that are related to the origin of life in the Universe are formed.

Credit: Samara University


Their attention to this topic was attracted, among other things, by the results of the NASA and the European Space Agency mission "Cassini-Huygens" to Saturn's largest moon, Titan. During the space mission of an automatic interplanetary station the benzene molecule was discovered in the atmosphere of Titan. This, in turn, led scientists to believe that the emergence and growth of the orange-brownish haze layers that surround this moon is exactly the responsibility of PAHs. However, the fundamental chemical mechanisms leading to the chemical synthesis of PAHs in the atmosphere of Titan at very low temperatures were not disclosed.

Within the framework of the megagrant "Development of Physically Grounded Combustion Models" under the guidance of Professor of Florida International University Alexander Mebel, the scientists from Samara University searched for the mechanisms of PAH formation using modern high-precision quantum chemical calculation methods. Based on these data, their colleagues from the University of Hawaii and Lawrence Berkeley National Laboratory conducted laboratory experiments that confirmed that prototypes of PAH molecules (anthracene and phenanthrene) are synthesized in barrier-free reactions that take place at low temperatures typical of Titan atmosphere. Anthracene and phenanthrene, in turn, are the original "bricks" for larger PAH molecules, as well as precursors of more complex chemical compounds that were found in the orange-brownish organic haze layers surrounding the moon of Saturn.

"Experimental detection and theoretical description of these elementary chemical reactions change the well-established notion that PAHs can be formed and are able to grow only at very high temperatures, for example, in flames of organic fuels under terrestrial conditions, - concluded Alexander Mebel. - And this means that our discovery leads to the changing of existing scientific views on how PAHs can be formed and grow."

"Traditionally, models of PAH synthesis in hydrocarbon-rich atmospheres of the planets and their moons, such as Titan, assumed the presence of high temperatures, - emphasizes Professor at the University of Hawaii Ralf Kaiser. We provide evidence for a low-temperature reaction pathway".

Understanding the mechanism of PAH growth at low temperatures will allow scientists to understand how complex organic molecules that are related to the origin of life can be formed in the Universe. "Molecules similar to small PAHs, but containing nitrogen atoms, are key components of ribonucleic acids (RNA, DNA) and some amino acids, that is, components of proteins, - notes Alexander Mebel. - Therefore, the growth mechanism of PAHs can be associated with chemical evolution in the Universe, leading to the origin of life".

Moreover, the study of the atmosphere of Titan helps to understand the complex chemical processes occurring not only on the Earth, but also on other moons and planets. "Using new data, scientists can better understand the origin of life on the Earth at the time when nitrogen was more common in its atmosphere, as it is now on Titan", - said Musahid Ahmed, a scientist at Lawrence Berkeley National Laboratory.

As for the application of the presented work it should be mentioned that the understanding the mechanism of PAH growth in flames will allow the scientists of Samara University to offer engineers the mechanisms to reduce the release of these carcinogenic substances in the exhaust of various types of engines. And this is one of the main goals of the megagrant implemented by the University.

Polycyclic aromatic hydrocarbons are organic compounds which chemical structure contains two or more condensed benzene rings. In nature, PAHs are formed in the process of cellulose pyrolysis and are found in coal, brown coal and anthracite formations, and also as a product of incomplete combustion during forest fires. Many PAHs are potent carcinogens. The main sources of the emission of technogenic PAHs into the environment are enterprises of the energy complex, automobile transport, chemical and petroleum refining industry.

Megagrant "Development of Physically Grounded Combustion Models" has been implemented within the Russian Federation governmental support for scientific research since 2016. International scientific laboratory "Physics and Chemistry of Combustion" under the guidance of Professor of Florida International University Alexander Mebel was established to implement the megagrant in the University. The project is aimed at solving the burning problem -- prevention of environmental pollution. The results of research conducted by the scientists of Samara University in close cooperation with both international and Russian research centres will contribute to the creation of more environmentally friendly and efficient combustion chambers for gas turbine engines.


Contacts and sources:
Olga BuhnerSamara University




Citation:
Low-temperature formation of polycyclic aromatic hydrocarbons in Titan’s atmosphere
Long Zhao,  Ralf I. Kaiser,  Bo Xu,  Utuq Ablikim,  Musahid Ahmed,  Mikhail M. Evseev,  Eugene K. Bashkirov,  Valeriy N. Azyazov &  Alexander M. Mebel
Nature Astronomy (2018) http://dx.doi.org/10.1038/s41550-018-0585-y




Titanic Structure in the Early Universe Discovered



An international team of astronomers has discovered a titanic structure in the early Universe, just two billion years after the Big Bang. This galaxy proto-supercluster, nicknamed Hyperion, is the largest and most massive structure yet found at such a remote time and distance.

The team that made the discovery was led by Olga Cucciati of Istituto Nazionale di Astrofisica (INAF) Bologna, Italy and project scientist Brian Lemaux in the Department of Physics, College of Letters and Science at the University of California, Davis, and included Lori Lubin, professor of physics at UC Davis. They used the VIMOSinstrument on ESO's Very Large Telescope in Paranal, Chile to identify a gigantic proto-supercluster of galaxies forming in the early Universe, just 2.3 billion years after the Big Bang.

Hyperion is the largest and most massive structure to be found so early in the formation of the Universe, with a calculated mass more than one million billion times that of the Sun. This enormous mass is similar to that of the largest structures observed in the Universe today, but finding such a massive object in the early Universe surprised astronomers.

An international team of astronomers has discovered a titanic structure in the early Universe, just two billion years after the Big Bang. This galaxy proto-supercluster, nicknamed Hyperion, is the largest and most massive structure yet found at such a remote time and distance. It has a mass estimated at a million billion Suns.

Credit: Luis Calçada & Olga Cucciati/ESO


"This is the first time that such a large structure has been identified at such a high redshift, just over 2 billion years after the Big Bang," Cucciati said. "Normally these kinds of structures are known at lower redshifts, which means when the Universe has had much more time to evolve and construct such huge things. It was a surprise to see something this evolved when the Universe was relatively young."

Supercluster mapped in three dimensions

Located in the constellation of Sextans (The Sextant), Hyperion was identified by a novel technique developed at UC Davis to analyze the vast amount of data obtained from the VIMOS Ultra-Deep Survey led by Olivier Le Fèvre from Laboratoire d'Astrophysique de Marseille, Centre National de la Recherche Scientifique and Centre National d'Etudes Spatiales. The VIMOS instrument can measure the distance to hundreds of galaxies at the same time, making it possible to map the position of galaxies within the forming supercluster in three dimensions.

The team found that Hyperion has a very complex structure, containing at least seven high-density regions connected by filaments of galaxies, and its size is comparable to superclusters closer to Earth, though it has a very different structure.

"Superclusters closer to Earth tend to a much more concentrated distribution of mass with clear structural features," Lemaux said. "But in Hyperion, the mass is distributed much more uniformly in a series of connected blobs, populated by loose associations of galaxies."

The researchers are comparing the Hyperion findings with results from the Observations of Redshift Evolution in Large Scale Environments (ORELSE) survey, led by Lubin. The ORELSE survey uses telescopes at the W.M. Keck Observatory in Hawaii to study superclusters closer to Earth. Lubin and Lemaux are also using the Keck observatory to map out Hyperion and similar structures more completely.

The contrast between Hyperion and less distant superclusters is most likely due to the fact that nearby superclusters have had billions of years for gravity to gather matter together into denser regions -- a process that has been acting for far less time in the much younger Hyperion.

Given its size so early in the history of the Universe, Hyperion is expected to evolve into something similar to the immense structures in the local Universe such as the superclusters making up the Sloan Great Wall or the Virgo Supercluster that contains our own galaxy, the Milky Way.

"Understanding Hyperion and how it compares to similar recent structures can give insights into how the Universe developed in the past and will evolve into the future, and allows us the opportunity to challenge some models of supercluster formation," Cucciati said. "Unearthing this cosmic titan helps uncover the history of these large-scale structures."

This research will be published in an upcoming issue of the journal Astronomy & Astrophysics.


Contacts and sources:
Andy FellUniversity of California, Davis