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Thursday, March 23, 2017

New Study Shakes the Roots of The Dinosaur Family Tree, Corrects 130-Year-Old Error

More than a century of theory about the evolutionary history of dinosaurs has been turned on its head following the publication of new research from scientists at the University of Cambridge and Natural History Museum in London. Their work suggests that the family groupings need to be rearranged, re-defined and re-named and also that dinosaurs may have originated in the northern hemisphere rather than the southern, as current thinking goes.

For 130 years palaeontologists have been working with a classification system in which dinosaur species have been placed in to two distinct categories: Ornithischia and Saurischia. But now, after careful analysis of dozens of fossil skeletons and tens of thousands of anatomical characters, the researchers have concluded that these long-accepted familial groupings may, in fact, be wrong and that the traditional names need to be completely altered.

Credit: Natural History Museum

The classification of dinosaurs dates back to Victorian times. Dinosaurs were first recognised as a unique group of fossil reptiles in 1842 as a result of the work of the anatomist, Professor Richard Owen (who later went on to found the Natural History Museum in London). Over subsequent decades, various species were named as more and more fossils were found and identified. During the latter half of the 19th century it was realised that dinosaurs were anatomically diverse and attempts were made to classify them into groups that shared particular features.

Kulindadromeus, a small bipedal ornithischian dinosaur that is now part of the new grouping Ornithoscelida and identified as more obviously sharing an ancestry with living birds

Credit: Pascal Godefroid

It was Harry Govier Seeley, a palaeontologist trained in Cambridge under the renowned geologist Adam Sedgwick, who determined that dinosaurs fell quite neatly into two distinct groupings, or clades; Saurischia or Ornithischia. This classification was based on the arrangement of the creatures’ hip bones and in particular whether they displayed a lizard-like pattern (Saurischia) or a bird-like one (Ornithischia).

As more dinosaurs were described it became clear that they belonged to three distinct lineages; Ornithischia, Sauropodomorpha and Theropoda. In 1887 Seeley placed the sauropodomorphs (which included the huge ‘classic’ dinosaurs such as Diplodocus and Brontosaurus) together with the theropods (which included T. rex), in the Saurischia. The ornithischians and saurischians were at first thought to be unrelated, each having a different set of ancestors, but later study showed that they all evolved from a single common ancestor.

This new analysis of dinosaurs and their near relatives, published today in the journal Nature, concludes that the ornithischians need to be grouped with the theropods, to the exclusion of the sauropodomorphs. It has long been known that birds (with their obviously ‘bird-like’ hips) evolved from theropod dinosaurs (with their lizard-like hips). However, the re-grouping of dinosaurs proposed in this study shows that both ornithischians AND theropods had the potential to evolve a bird-like hip arrangement- they just did so at different times in their history.

Lead author, Matthew Baron, says: “When we started our analysis, we puzzled as to why some ancient ornithischians appeared anatomically similar to theropods. Our fresh study suggested that these two groups were indeed part of the same clade. This conclusion came as quite a shock since it ran counter to everything we’d learned.”

“The carnivorous theropods were more closely related to the herbivorous ornithischians and, what’s more, some animals, such as Diplodocus, would fall outside the traditional grouping that we called dinosaurs. This meant we would have to change the definition of the ‘dinosaur’ to make sure that, in the future, Diplodocus and its near relatives could still be classed as dinosaurs.”

The revised grouping of Ornithischia and Theropoda has been named the Ornithoscelida which revives a name originally coined by the evolutionary biologist, Thomas Henry Huxley in 1870.

Co-author, Dr David Norman, of the University of Cambridge, says: “The repercussions of this research are both surprising and profound. The bird-hipped dinosaurs, so often considered paradoxically named because they appeared to have nothing to do with bird origins, are now firmly attached to the ancestry of living birds.”

For 130 years palaeontologists have considered the phylogeny of the dinosaurs in a certain way. Our research indicates they need to look again at the creatures’ evolutionary history. This is simply science in action. You draw conclusions from one body of evidence and then new data or theories present themselves and you have to suddenly reconsider and adapt your thinking. All the major textbooks covering the topic of the evolution of the vertebrates will need to be re-written if our suggestion survives academic scrutiny.”

While analysing the dinosaur family trees the team arrived at another unexpected conclusion. For many years, it was thought that dinosaurs originated in the southern hemisphere on the ancient continent known as Gondwana. The oldest dinosaur fossils have been recovered from South America suggesting the earliest dinosaurs originated there. But as a result of a re-examination of key taxa it’s now thought they could just as easily have originated on the northern landmass known as Laurasia, though it must be remembered that the continents were much closer together at this time.

Co-author, Prof Paul Barrett, of the Natural History Museum, says: "This study radically redraws the dinosaur family tree, providing a new framework for unravelling the evolution of their key features, biology and distribution through time. If we're correct, it explains away many prior inconsistencies in our knowledge of dinosaur anatomy and relationships and it also highlights several new questions relating to the pace and geographical setting of dinosaur origins".

The research was funded through a Natural Environment Research Council (NERC) CASE studentship.

Contacts and sources:
Paul Seagrove
Cambridge University

Citation: Matthew Baron et al: 'A new hypothesis of dinosaur relationships and early dinosaur evolution' Nature, 23 March 2017


Breakthrough May Make Blood Test Feasible for Detecting Cancer

Doctors may soon be able to detect and monitor a patient's cancer with a simple blood test, reducing or eliminating the need for more invasive procedures, according to Purdue University research.

W. Andy Tao, a professor of biochemistry and member of the Purdue University Center for Cancer Research, and colleagues identified a series of proteins in blood plasma that, when elevated, signify that the patient has cancer. Their findings were published in the early edition of the Proceedings of the National Academy of Sciences.

Tao's work was done with samples from breast cancer patients, but it is possible the method could work for any type of cancer and other types of diseases. The work relies on analysis of microvesicles and exosomes in blood plasma.

Andy Tao, a professor at Purdue University's College of Agriculture, discovers a protein that could make cancer detection possible through a blood test

Credit: Purdue Agricultural Communications/Tom Campbell

Protein phosphorylation, the addition of a phosphate group to a protein can lead to cancer cell formation. So phosphorylated proteins, known as phosphoproteins, have been seen as prime candidates for cancer biomarkers. Until now, however, scientists weren't sure identification of phosphoproteins in blood was possible because the liver releases phosphatase into the bloodstream, which dephosphorylates proteins.

"There are so many types of cancer, even multiple forms for different types of cancer, that finding biomarkers has been discouraging," Tao said. "This is definitely a breakthrough, showing the feasibility of using phosphoproteins in blood for detecting and monitoring diseases."

Tao and his colleagues found nearly 2,400 phosphoproteins in a blood sample and identified 144 that were significantly elevated in cancer patients. The study compared 1-milliliter blood samples from 30 breast cancer patients with six healthy controls.

The researchers used centrifuges to separate plasma from red blood cells, and high-speed and ultra-high-speed centrifuges to further separate microvesicles and exosomes. Those particles, which are released from cells and enter the bloodstream, may play a role in intercellular communication and are thought to be involved in metastasis, spreading cancer from one place to another in the body. They also encapsulate phosphoproteins, which Tao's team identified using mass spectrometry.

"Extracellular vesicles, which include exosomes and microvesicles, are membrane-encapsulated. They are stable, which is important," Tao said. "The samples we used were 5 years old, and we were still able to identify phosphoproteins, suggesting this is a viable method for identifying disease biomarkers."

A simple blood test for cancer would be far less invasive than scopes or biopsies that remove tissue. A doctor could also regularly test a cancer patient's blood to understand the effectiveness of treatment and monitor patients after treatment to see if the cancer is returning.

"There is currently almost no way to monitor patients after treatment," Tao said. "Doctors have to wait until cancer comes back."

Timothy Ratliff, director of the Purdue University Center for Cancer Research, said the findings are promising for early detection of cancer.

"The vesicles and exosomes are present and released by all cancers, so it could be that there are general patterns for cancer tissues, but it's more likely that Andy will develop patterns associated with different cancers. It's really exciting," Ratliff said. "Early detection in cancer is key and has been shown to clearly reduce the death rate associated with the disease."

Tao plans to analyze increased levels of phosphoproteins in various types of cancer to determine whether there are patterns that would signify the type of cancer a patient has. His company, Tymora Analytical, is also developing technology that would allow doctors to insert blood samples onto a cartridge and analyze phosphoproteins present, eliminating the need for ultra-high-speed centrifuges that aren't practical in clinical settings.

The National Institutes of Health, the National Science Foundation and the Purdue University Center for Cancer Research supported Tao's research.

Contacts and sources:: 
Shari Finnell
Purdue University

Citation: Phosphoproteins in Extracellular Vesicles as Candidate Markers for Breast Cancer

6000 Year Old Egyptian Ritual Images Linked to The Neolithic Period

Egyptologists at the University of Bonn discovered rock art from the 4th millennium BC during an excavation at a necropolis near Aswan in Egypt. The paintings were engraved into the rock in the form of small dots and depict hunting scenes like those found in shamanic depictions. They may represent a link between the Neolithic period and Ancient Egyptian culture. The discovery earned the scientists the award for one of the current ten most important archeological discoveries in Egypt from the Minister of Antiquities in Cairo.

For more than 100 years, Qubbet el-Hawa (English: hill of wind) has been a magnet for archeology. Over 80 burial mounds have been uncovered on the hill near Aswan in Egypt during countless excavations. The history of this necropolis for the provincial capital Elephantine extends from around 2200 to the 4th century BC. It was an important trading base for Egyptians in Nubia, and their nobles were buried in the burial mounds. Prof. Elmar Edel from the University of Bonn investigated and documented the necropolis from 1959 to 1984. "The majority of the objects in the Egyptian Museum in Bonn come from these field campaigns," reports Prof. Ludwig Morenz, who heads Egyptology at the Bonn alma mater.

The around 6000-year-old rock engravings can hardly be seen today. They were pecked into the rock with a hard point.

Credit: © Photo: David Sabel

A completely new aspect at Qubbet el-Hawa has now been uncovered during an excavation begun at the necropolis in 2015. The team led by Prof. Morenz with Amr El Hawary, Andreas Dorn, Tobias Gutmann, Sarah Konert and David Sabel discovered much older Neolithic rock art from the 4th millennium BC. "Style and iconography provide solid clues when dating these," says the scientist. "It opens up a new archeological dimension". Some of these engravings on the rock wall are clearly Egyptian in terms of iconography and stylistics, while others are clearly pre-Egyptian as regards the presentation method and motif.

The images were pecked into the rock with a hard point and are now barely perceivable due to their considerable age. Only the archeologically precise recording of the traces and the drawing of the outlines revealed the images with noteworthy iconography. The initially confusing-looking arrangement of dots allows three figures to be seen upon closer inspection: a hunter with bow, a dancing man with raised arms and, between them, an African ostrich.

The intentionally overvisualized tracing with inherent interpretation allows three figures to be identified: a hunter with a bow (right), a dancing man with a bird mask (left) and, in the center, the large flightless bird the ostrich.

Credit: © David Sabel

"The archer clearly shows hunting for the large flightless bird, while the man with raised arms can be identified as a hunt dancer," reports Prof. Morenz. The dancer apparently wears a bird mask. The scene is reminiscent of the conceptual world of hunting, masks and shamanism, as known from many parts of the Earth - including of ostrich hunting by what are known as San (bushmen).

Such hunting and dancing scenes are new in Egyptology

"This social practice and the associated complex of ideas have barely been looked at in Egyptology," says Prof. Morenz. Small painted female figures with dancing, raised arms and a bird mask also come from the 4th millennium BC, and some clay masks were discovered a few years ago in the Upper Egyptian Hierakonpolis. These finds show astounding consistency with the rock paintings of Qubbet el-Hawa.

Here the scientists at the University of Bonn have discovered the spectacular rock paintings. 

Credit: © Photo: David Sabel

They may represent a link between the ancient Near Eastern and even southern European Neolithic period and Ancient Egyptian culture. "This opens up new horizons for research," says Prof. Morenz. However, the finds need to be investigated more closely. The much older rock art clearly has nothing to do with the necropolis directly and is probably linked to a prehistoric network of trails that also needs to be researched more intensively.

Award from the Egyptian Minister of Antiquities

Despite the comparably short excavation time, the discovery by the team of scientists at the University of Bonn has already earned an award: to mark Egyptology day in Cairo, the Egyptian Minister of Antiquities Prof. Khaled El-Enany recently honored this mission with the award for one of the current ten most important archeological discoveries in Egypt.

Contacts and sources:
Prof. Ludwig D. Morenz
University of Bonn

Got Low-T: Ads for Low-Testosterone Treatments Benefit Sales but Not Necessarily Health

Direct-to-consumer advertising for drugs to treat testosterone deficiency — or “low T” — increases prescriptions to men for hormone-replacement therapies but may not improve their health, UC Davis physician Richard Kravitz said in an editorial published in the March 21 issue of the Journal of the American Medical Association.

Kravitz, a professor of internal medicine and researcher on improving communications between patients and their physicians, said an increase in ads and prescriptions for hormone-replacement therapies beginning around 2000 preceded professional guidelines for physicians and product-safety research and led to unnecessary treatments for low testosterone, or age-related hypogonadism.

“Between 2000 and 2011, testosterone use increased at least 3-fold in the United States,” Kravitz wrote. “Many men who were treated with these products did not undergo appropriate testing for testosterone deficiency or meet diagnostic criteria for hypogonadism.”
Credit: University of Miami/Wikimedia Commons

The likelihood of hypogonadism increases with age and can cause symptoms such as low libido, reduced strength, fatigue and depression. It is diagnosed with a blood test together with clinical symptoms and signs, and it is treated with products that increase levels of male-reproductive hormones known as androgens, most often testosterone, through injections, gels, transdermal patches or subcutaneous pellets.

In his editorial, Kravitz referenced a study in the same issue of the journal estimating that “1 additional exposure to an androgen replacement therapy television advertisement was associated with 14 new tests, 5 new initiations, and 2 initiations without testing per million men exposed,” suggesting that “patients respond to [direct-to-consumer-advertising] and physicians respond to patients.”

When medical research began to link androgen replacement therapy with cardiovascular disease, the number of ads for these products declined starting in 2014, likely due to U.S. Food and Drug Administration requirements for informing consumers in drug advertising about potential risks, according to Kravitz.

Credit: Vimeo

“But with revenue from topical testosterone products topping $2.2 billion the year before, the market for androgen replacement therapy was still substantial,” he wrote.

While restrictions on direct-to-consumer medication ads — such as limits on timing and content — have been proposed, Kravitz wrote that a complete ban is unlikely given free speech protections. He recommended continued research on the topic, since direct-to-consumer advertising, “while a potentially powerful tool in motivating patient behavior and perhaps even physician prescribing, does not necessarily serve to improve the health of patients or the public.”

Contacts and sources:
Karen Finney
University of California Davis

The Foundation of Aquatic Life Can Rapidly Adapt to Global Warming:

Important microscopic creatures which produce half of the oxygen in the atmosphere can rapidly adapt to global warming, new research suggests.

Phytoplankton, which also act as an essential food supply for fish, can increase the rate at which they take in carbon dioxide and release oxygen while in warmer water temperatures, a long-running experiment shows.

Monitoring of one species, a green algae, Chlamydomonas reinhardtii, after ten years of them being in waters of a higher temperature shows they quickly adapt so they are still able to photosynthesise more than they respire.

Phytoplankton can increase the rate at which they take in carbon dioxide and release oxygen while in warmer water temperatures.
Credit:  University of Exeter

Phytoplankton use chlorophyll to capture sunlight, and photosynthesis to turn it into chemical energy. This means they are critical for reducing carbon dioxide in the atmosphere and for providing food for aquatic life. It is crucial to know how these tiny organisms – which are not visible to the naked eye – react to climate change in the long-term. Experts had made predictions that that climate change would have negative effects on phytoplankton. But a new study shows green algae can adjust to warmer water temperatures. They become more competitive and increase the amount they are able to photosynthesise.

Algae examined by scientists which lived in warmer waters became fitter, and more competitive, proving that these tiny creatures adapt well to climate change. This suggests that this species could continue to be a plentiful source of food for aquatic life even if temperatures rise. Previous studies which sought to answer this question have been conducted only in laboratories rather than looking at how phytoplankton reacted to real conditions. In contrast this research, which has run so far for ten years, has allowed researchers to examine how the green algae fare in their natural environment, where they are exposed to a more complex environment, and competitors.

Scientists at the University of Exeter’s Penryn campus in Cornwall have for a decade monitored ten tanks home to the phytoplankton with freshwater heated to four degrees centigrade above the ambient temperature. This is the rate at which our climate will have been warmed by the end of the century. The temperatures of ten other tanks were kept at normal temperatures. All the tanks were kept outside the Freshwater Biological Association’s river laboratory in Dorset. All twenty tanks were populated with the same types and proportion of various freshwater phytoplankton, zooplankton, invertebrates and plants. In the laboratory scientists tested how much the algae could photosynthesise, how fast they were growing, and how well they outcompeted organisms from the ambient ponds.

Lead author Dr Elisa Schaum said: “phytoplankton may be microscopically small, but they are essential for all aquatic life. They provide food for zooplankton, which are then eaten by fish. Aquatic ecosystems produce the oxygen in every second breath we take, and are responsible for the oceans’ capacity as a sink for carbon dioxide.

“Other research had suggested that increased temperatures can pose problems for some types of phytoplankton. But we have shown that algae adapt very rapidly and that the mechanism underpinning their evolutionary response is linked to higher rates of photosynthesis – they can produce more energy, and channel it into faster growth rates and a better capacity for competition with other algae. They divide once a day and live in large populations of thousands of cells per millilitre of water. This means evolutionary changes are made through a few hundred of generations within a couple of years.

“It is important to recognise that climate change is a serious threat to aquatic ecosystems. Although the green algae monitored in our study cope well with elevated temperature, and may be able to sustain populations of organisms that eat them, we do not know yet what will happen to other groups of algae, and whether or not they will adapt through the same mechanisms.”

Adaptation of phytoplankton to a decade of experimental warming linked to increased photosynthesis by Elisa Schaum, Samuel Barton, Elvire Bestion, Angus Buckling, Bernardo Garcia-Carreras, Paula Lopez, Chris Lowe, Samraat Pawar, Nicholas Smirnoff, Mark Trimmer and Gabriel Yvon-Durocher (who is the group’s principle investigator) is published in the journal Nature Ecology and Evolution.

Contacts and sources:
Kerra Maddern
University of Exeter

Comet 67P Full of Surprises, Says New Study

Images returned from the European Space Agency's Rosetta mission indicate the surface of comet 67P/Churyumov-Gerasimenko was a very active place during its most recent trip through the solar system, says a new study led by CU Boulder.

The images show the comet's surface is full of growing fractures, collapsing cliffs and massive rolling boulders. Moving material buried some features on the comet’s surface and exhumed others. A study on 67P’s changing surface was released Tuesday in the journal Science.

"As comets approach the sun, they go into overdrive and exhibit spectacular changes on their surface," said Ramy El-Maarry, study leader and a member of the U.S. Rosetta science team who is a research scientist at CU Boulder's Laboratory for Atmospheric and Space Physics. "This is something we were not able to really appreciate before the Rosetta mission, which gave us the chance to look at a comet in ultra-high resolution for more than two years."

Comet 67P. 

Photo courtesy of NASA

The Jet Propulsion Laboratory (JPL) in Pasadena, California, a division of the California Institute of Technology in Pasadena, manages the U.S. contribution of the Rosetta mission for NASA's Science Mission Directorate in Washington, D.C. JPL also built the MIRO instrument and hosts its principal investigator, Mark Hofstadter.

Most comets orbit the sun in highly elliptical orbits that cause them to spend most of their time in the extremely cold outer solar system. When a comet approaches the inner solar system, the sun begins to warm the ice on and near the comet's surface.

When the ice warms enough it can rapidly sublimate, turning directly from a solid to a vapor state. This sublimation process can occur with variable degrees of intensity and timing and cause the surface to change rapidly. Between August 2014 and September 2016, Rosetta orbited comet 67P during the comet's swing through the inner solar system.

"We saw a massive cliff collapse and a large crack in the neck of the comet get bigger and bigger," said El-Maarry. "And we discovered that boulders the size of a large truck could be moved across the comet's surface – a distance as long as one-and-a-half football fields."

In the case of the boulder, Rosetta's cameras observed a 282-million-pound, 100-foot- wide space rock that had moved 450 feet from its original position on the comet’s nucleus. The massive space rock probably moved as a result of several cometary "outburst" events that were detected close to its original position, said El-Maarry.

The warming of 67P also caused the comet's rotation rate to speed up. The comet's increasing spin rate in the lead up to perihelion (when the comet was closest to the sun) is thought to be responsible for a 1,600-foot-long fracture spotted in August 2014 that runs through the comet's neck.

The fracture, which originally extended a bit longer than the Empire State Building is high, was found to have increased in width by about 100 feet by December 2014. In images taken in June 2016, a new 500- to 1,000-foot-long fracture was identified parallel to the original fracture.

"The large crack was in the neck of the comet, a small central part that connects the two lobes," said El-Maarry. "The crack was extending, indicating that the comet may split up one day."

Rosetta is a European Space Agency mission with contributions from its member states and NASA. Other institutions involved in the mission include the German Aerospace Center in Cologne, Germany; the Max Planck Institute for Solar System Research in Gottingen, Germany; the French National Space Agency in Paris; and the Italian Space Agency in Rome.

The Southwest Research Institute in San Antonio, Texas, and Boulder, Colorado developed the Rosetta orbiter's Ion and Electron Sensor (IES) and Alice instruments and hosts their principal investigators, James Burch (IES) and Joel Parker (Alice).

Contacts and sources:
Ramy El-Maarry
University of Colorado Boulder.  
 More information about Rosetta is available at http://www.esa.int/rosetta.

Amazon River No Younger Than 9 Million Years, New Study Shows

Researchers from the University of Amsterdam (UvA) and the University of Brasilia (Brazil) have determined the age of the formation of the Amazon River at 9.4 to 9 million years ago (Ma) with data that convincingly refutes substantial younger estimates. Their results are published as early view in the journal Global and Planetary Change.

The study comprised geochemical and palynological analyses of sediments from a hydrocarbon exploration borehole, situated offshore of Brazil, that reached more than 4.5 kilometers below sea level.

The results show a distinct change in sediment composition and plant residual matter during the late Miocene (9.4 to 9 Ma). This represents a switch in river source area from the tropical lowlands to the high Andes, which is diagnostic of the onset of the transcontinental Amazon River. The new data contradict younger estimates (c. 2.6 Ma) that have been proposed in recent literature and postdates estimates from an earlier study of this borehole by about 1 to 1.5 million years.

Map of the Amazon River drainage basin with the Amazon River highlighted.
Credit: Wikipedia

Sediments record evolutionary history

‘We were able to narrow down the age of onset of the Amazon River because we sampled the transition interval in a classical section of the Amazon submarine fan, where the sediments transported by this river are deposited and as a result accurately record its evolutionary history. We applied high resolution analytical techniques not previously performed in the region’, says professor Farid Chemale, senior author from the University of Brasilia (now at Universidade do Vale do Rio dos Sinos, São Leopoldo).

Amazon river mouth 
Credit: ESA

The study also gives novel insights into overall changes in plant composition in the Amazon drainage basin. Particularly, the rise in grass remains suggests that mountain uplift and Quaternary climatic changes strongly affected the landscape and probably opened up new habitats for grass colonization.

Dramatic changes

‘The changes detected in the sediment record lead to the tantalizing question of whether the Amazon region might have changed dramatically during Plio-Pleistocene global cooling’, says Dr Carina Hoorn, lead author and researcher at the UvA’s Institute for Biodiversity and Ecosystem Dynamics. ‘Our new data confirm an old age for the Amazon River and also point at an expansion of grasslands during the Pleistocene that was not known before. Further research on land and at sea may give further answers but will require investment in both continental and marine drilling.’

Largest drainage basin of all rivers

The Amazon River contributes a fifth of the total fresh water supply to the global oceans and has the largest drainage basin of all rivers around the world. The onset of the river is a defining moment in the reorganization of the paleogeography of South America, forming both a bridge and a divider for biota in the Amazon landscape.
Source of the Amazon
Credit: NASA

The history of the Amazon River and its drainage basin are hard to unravel, as the continental record is scarce and fragmented. The marine record is more complete, yet is equally difficult to access. Sediment aprons in the proximity of major rivers often hold continuous records of terrestrial material accumulated by the river over time. These records provide a unique insight into the historic climate, geography and biome evolution of the land.

Clim-Amazon project

The research was carried out in the context of the Clim-Amazon project, a joint Brazilian-European scientific initiative for climate and geodynamic research on the Amazon River Basin sediment and is supported by the EU (European Union) through the FP7 (Seventh Framework Programme for Research and Technological Development). See: http://www.clim-amazon.eu

Contacts and sources:
University of Amsterdam (UvA)

Citation: The Amazon at Sea: Onset and stages of the Amazon River from a marine record, with special reference to Neogene plant turnover in the drainage basin. 
Hoorn, C., Bogotá-A., G.R., Romero-Baez, M., Lammertsma, E.I., Flantua, S.G.A., Dantas, E.L., Dino, R., do Carmo, D.A., Chemale Jr., F., 2017. DIO: 10.1016/j.gloplacha.2017.02.005

Looking for Signs of the Big Bang and Primordial Gravitational Waves

The silence of an immense desolate land in which to search for reverberations coming from the time at which everything began. The Simons Observatory will be built in the Chilean Atacama desert at an altitude of several thousand metres for the purposes of studying primordial gravitational waves which originated in the first instants of the Big Bang. 

The SISSA research group led by Carlo Baccigalupi and Francesca Perrotta will take part in this prestigious international project which will lead to the realization of an ultra-modern telescope project. Their role will involve studying and removing ‘signal contaminants’, emissions from our galaxy and other astrophysical objects which interfere with the analysis and study of primordial gravitational waves.

“Studying and measuring these waves, which originated just a few instants after the Big Bang means getting even closer to that zero-moment when the universe began”. This is how cosmologists Carlo Baccigalupi and Francesca Perrotta explained the importance of the research which will see them involved in an international project funded by the Simons Foundation and the Heising-Simons Foundation. 

Credit:  iStock by GettyImages. Photographer: reubenheydenrych

“It is one of the great astrophysics and cosmology themes on which a lot of work is being done and which is bringing us important new scientific discoveries and challenges thanks to the progress made with the Planck probe. The Simons Observatory, for which 40 million dollars have been set aside, will make a great contribution to this”, continued the researchers.

Gravitational waves are distortions of the space-time curvature which propagate like waves. Foreseen by the theory of General Relativity but not by Newton’s theory of gravity, these are phenomena which have only been directly observed extremely recently, in 2015, as a result of the work of the LIGO interferometer team, as emissions resulting from the collision of two black holes dozens of times bigger than the sun. This extraordinary discovery gave a further powerful boost to the scientific community’s research into gravitational waves generated by the Big Bang.

The realization of the huge telescope project which will enable scientists to study these waves should begin in around two years’ time. All of the research groups involved will be meeting up in California this summer to decide on the technical characteristics of this ultra-sophisticated tool. The first observations are expected by the end of the decade. In a joint project involving the United States, Japan and Europe, SISSA - for now the only Italian partner - will be playing an important role.

In the words of Baccigalupi and Perrotta: “Our research group, involving also Davide Poletti, Nicoletta Krachmalnicoff and Giuseppe Puglisi, together with european institutions such as the Paris Laboratory of Astrophysics and Cosmology and Imperial College, London, we will study signal contaminants, i.e. the emissions coming from our galaxy, such as dust or gas, which can interfere with the analysis of primordial gravitational waves. What we will do is to attempt to measure polluting signals and eliminate them by means of applying mathematical models to the data. The Simons Observatory will be the focus for a study which will play a part in an already well-established research line for the Trieste group. Also related to this, the SISSA team is a participant in RadioForegrounds, a project which is part of the European Commission’s Horizon 2020 and of which Francesca Perrotta is the Italian lead.

The Atacama desert, with an area of more than 100,000 km2, is considered one of the driest places in the world and experiments are already under way there, with pre-existing telescopes such as that used in the POLARBEAR experiment (at an altitude of 5200 metres) in which SISSA’s scientists are playing an active part studying the cosmic microwave background. Two further telescopes, called the Simons Array, are already being built in the same area. These will now be joined by the larger Simons Observatory telescope program.

Contacts and sources:
Nico Pitrelli 

Riding ‘Drifting Carousel' to Understand Pulsars, the ‘Lighthouses in Space’

What sounds like a stomach-turning ride at an amusement park might hold the key to unravelling the mysterious mechanism that causes beams of radio waves to shoot out from pulsars − super-magnetic rotating stars in our Galaxy.

New research from Curtin University, obtained using the Murchison Widefield Array (MWA) radio telescope located in the Western Australian outback, suggests the answer could lie in a ‘drifting carousel’ found in a special class of pulsars.

Curtin PhD student Sam McSweeney, who led the research as part of his PhD project with the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) and the International Centre for Radio Astronomy Research (ICRAR), described pulsars as extremely dense neutron stars that emit beams of radio waves.

“These pulsars weigh about half a million times the mass of the Earth but are only 20km across,” Mr McSweeney said.

Schematic view of a pulsar. The sphere in the middle represents the neutron star, the curves indicate the magnetic field lines and the protruding cones represent the emission zones. 

Image credit: Mysid

“They are nicknamed ‘lighthouses in space’ because they appear to ‘pulse’ once per rotation period, and their sweeping light signal can be seen through telescopes at exceptionally regular intervals.”

Thousands of pulsars have been seen since their first discovery in the late 1960s, but questions still remain as to why these stars emit radio beams in the first place, and what type of emission model best describes the radio waves, or ‘light’, that we see.

“The classical pulsar model pictures the emission that is shooting out from the magnetic poles of the pulsar as a light cone,” Mr McSweeney said.

“But the signal that we observe with our telescopes suggests a much more complex structure behind this emission – probably coming from several emission regions, not just one.”


The ‘drifting carousel’ model manages to explain this complexity much better, describing the emission as coming from patches of charged particles, arranged in a rotating ring around magnetic field lines, or a carousel.

“As each patch releases radiation, the rotation generates a small drift in the observed signal of these sub-pulses that we can detect using the MWA,” Mr McSweeney said.

“Occasionally, we find that this sub-pulse carousel gets faster and then slower again, which can be our best window into the plasma physics underlying the pulsar emission.”

One possibility the researchers are currently testing is that surface temperature is responsible for the carousel changing rotation speed: localised ‘hotspots’ on the pulsar surface might cause it to speed up.


“We will observe individual pulses from these drifting pulsars across a wide range of radio frequencies, with lower frequency data than ever before,” Mr McSweeney said.

“Looking at the same pulsar with different telescopes simultaneously will allow us to trace the emission at different heights above their surface.”

The researchers plan to combine the data from the MWA, the Giant Metre-wave Radio Telescope in India and the CSIRO Parkes Radio Telescope in New South Wales to – literally – get to the bottom of the mysterious pulses.

A paper explaining the research “Low Frequency Observations of the Subpulse Drifter PSR J0034-0721 with the Murchison Widefield Array” was recently published in The Astrophysical Journal.

CAASTRO is a collaboration of The University of Sydney, The Australian National University, The University of Melbourne, Swinburne University of Technology, The University of Queensland, The University of Western Australia and Curtin University, the latter two participating together as the International Centre for Radio Astronomy Research (ICRAR). CAASTRO is funded under the Australian Research Council (ARC) Centre of Excellence program, with additional funding from the seven participating universities and from the NSW State Government’s Science Leveraging Fund.

ICRAR is a joint venture between Curtin University and The University of Western Australia and supported by the Western Australian Government.

The Murchison Widefield Array (MWA) is a low frequency radio telescope located at the Murchison Radio-astronomy Observatory in Western Australia’s Mid-West. The MWA observes radio waves with frequencies between 70 and 320 MHz and was the first of the three Square Kilometre Array (SKA) precursors to be completed.

Contacts and sources:
Sam McSweeney
CAASTRO, ICRAR, Curtin Institute of Radio Astronomy

Wednesday, March 22, 2017

Gluten Free Rice-Flour Bread Could Revolutionize Global Bread Production

100% natural, 100% gluten free - get ready for the battle of the grain.

Hiroshima University researchers have resolved the science behind a new bread-baking recipe. The method for making gluten-free bread, developed by Japan’s National Agriculture and Food Research Organization, NARO - uses rice-flour to produce bread with a similar consistency and volume to traditional wheat-flour loaves.

While rice-flour breads are not new, up until now their consistencies have either lacked the familiar bubble structure and volume found in wheat-flour bread – or this bubble structure has been artificially induced through additives.

Successful Rice Flour Bread
Credit: Hiroshima University 

This new rice bread is 100% natural, and importantly has a similar consistency expected by consumers used to wheat breads. This gluten-free alternative should appeal to celiac sufferers who can’t consume gluten, and to people who wish to avoid gluten in their diets.

How it works

Wheat-flour bread’s familiar texture is down to gluten’s ability to form a flexible matrix. This matrix stabilizes the thin dough/bread walls that form between CO2 bubbles released by fermenting yeast. It also enables bread to “rise” in response to increasing CO2 levels during the baking process.

Rice flour does not contain gluten so how are these vital bread characteristics achieved in this new bread recipe?

The secret lies in the processing of the rice flour used. Not all rice flours produce a satisfactory batch, hence why this simple technique has remained undiscovered for so long! NARO found that rice flour produced by a specific type of wet milling was the key.

Using this wet-milled flour to make bread, they observed the microstructure of the fermenting batter (rice flour does not form dough), and the resulting loaf - both contained bubbles coated in uniform undamaged starch particles in a “stone wall” arrangement.

Effect of undamaged starch in reducing water tension
Credit: Hiroshima University

When Hiroshima University researchers investigated this ingredient, they found it possessed amazingly novel properties not seen in rice-flour before – and these were down to the undamaged starch particles that resulted from its specific milling technique.

These stable “stone walls” apparently form due to the surface activity demonstrated by undamaged starch granules. It appears these granules are able to lower the surface tension of water and so reduce the tendency of the formed bubble walls to collapse! Other rice-flours tested, consisting of damaged starch, did not have the same water-tension lowering effect. They were thus devoid of these stable bubbles, and attempts to make bread with them fell flat.

Another factor hypothesized for undamaged starch bubble-stability in successful bread production is the uniform hydrophobicity of the similar sized granules - leading to their confinement to the interface between damp gaseous air pockets and the liquid batter.

This tightknit “stone wall” arrangement thus allows bubbles to grow and expand as CO2 levels increase within leading to successful voluminous bread.

Great Potential

Should producers see the benefits of moving to gluten-free rice flour for bread production it could conceivably shift the focus of global grain production from the prairies and steppes of the world to the paddy fields of Asia.

Hiroyuki Yano (NARO) and Masumi Villeneuve (Hiroshima University)
Credit: Hiroshima University 

This would contribute to increased rice exports at a time when consumption of the staple has decreased with the adoption of western dietary habits – including ironically the eating of more bread!

From a food science point of view - this newly discovered example of a food swelling mechanism could lead to the development of new unconceived foods with unique and exciting properties.

Contacts and sources:
Hiroshima University

Citation: Development of gluten-free rice bread: Pickering stabilization as a possible batter-swelling mechanism

Hiroyuki Yano, Akiko Fukui, Keiko Kajiwara, Isao Kobayashi, Koh-ichi Yoza, Akiyoshi Satake, Masumi Villeneuve Available online 1 December 2016

Archaeologists Find Prostate Stones, Shed New Light on 'Modern' Medical Problem

Archaeologists have helped solve a centuries’ old medical mystery which could change the way doctors today view the common condition of prostate stones.

An international team of researchers, including experts at Durham University, used neutron beam technology to identify three stone-like objects found during excavations of a prehistoric grave in Central Sudan.

They discovered that the mysterious objects were prostate stones – a condition previously thought to be exclusive to the modern era.

The find proves that far from being a modern condition, prostate stones also affected prehistoric men, even though their lifestyle and diet were significantly different to our own.

Prostate stone found in Central Sudan. 

Credit: D. Usai et al

The researchers hope their find might now provide medical researchers with the opportunity to learn more about what causes the disease.

The findings are published in the journal PLOS One.

“First known evidence”

Research co-author Dr Tina Jakob, in Durham’s Department of Archaeology, said: “Although bladder stones have been discovered at other archaeological sites, this is the first known evidence of severe prostate calcification affecting men as early as 10,000 BC.

“This is a truly remarkable discovery and will change the way we look at prostatic stones as a modern medical phenomenon.”

While excavating a cemetery in Central Sudan in 2013, a team of archaeologists from the UK and Italy unearthed a pre-Mesolithic burial with an unusual feature.

Three stone-like objects were found within the pelvic area of an adult male and it was initially thought they could be kidney, bladder or gall stones.

The stones were oval and irregular in shape with diameters ranging between 26mm and 30mm, weighing between 12g and 15g.

Common condition

Nowadays, prostatic stones are a common condition for modern men, affecting about 75 per cent of the middle-aged population – although most stones only grow to a few millimetres in diameter before being treated.

Extensive tests were carried out on the stones using the Science and Technology Facilities Council’s ISIS facility, the UK’s centre for studying the properties of materials on the atomic scale.

By measuring how neutrons were scattered by the stone sample, the researchers built up a picture of its mineral nature.

They were then able to identify the objects as prostate stones. Although archaeologists cannot say whether these stones killed the man, they were large enough to cause intense pain and affect his quality of life.

Neutron beam

Dr Antonella Scherillo, the lead scientist operating the neutron beam at ISIS, said: “We were delighted to be able to help the archaeologists find out the nature of these unusual objects.

“Using ISIS’ powerful neutron beam we were able to analyse the phase composition of the object without causing any damage.

“This is how we found out the stones were in fact prostate stones – a remarkable discovery considering the age of the burial site.”

Radiocarbon dating

Until now, the earliest possible discovery of calculi – a hard mass formed by minerals in the body – was from an Italian grave from around 6,500 BC.

The cemetery of Al Khiday, where the individual with the prostate stones was found, is located in Central Sudan on the left bank of the White Nile, and is home to 190 graves of various ages.

Archaeologists were able to deduce the age of these remains by the style of burial and a detailed study of the mineral deposition of the bones, as well as radiocarbon dating the rock and soil in the burial site, which suggested the male lived around 10,000 BC.

Universe's Ultraviolet Background May Provide Clues About Missing Galaxies

Astronomers have developed a way to detect the ultraviolet (UV) background of the Universe, which could help explain why there are so few small galaxies in the cosmos.

UV radiation is invisible but shows up as visible red light when it interacts with gas.

An international team of researchers led by Durham University, UK, has now found a way to measure it using instruments on Earth.

The researchers said their method can be used to measure the evolution of the UV background through cosmic time, mapping how and when it suppresses the formation of small galaxies.

The study could also help produce more accurate computer simulations of the evolution of the Universe.

 This movie follows the formation of galaxies with cosmic time, illustrating how ultraviolet (UV) radiation from other galaxies and from quasars suppresses the formation of stars inside small galaxies near to large galaxies similar to the Milky Way and Andromeda. The left panel shows a simulation that includes such diffuse UV radiation as in the real universe, where fewer smaller galaxies form. For comparison, the right panel shows what would happen in the absence of such radiation, with more small galaxies forming.
Credit:  University of Durham, S. McAlpine/S. Berry

The findings are published today (Wednesday, 22 March) in the journal Monthly Notices of the Royal Astronomical Society.

UV radiation - a type of radiation also given out by our Sun - is found throughout the Universe and strips smaller galaxies of the gas that forms stars, effectively stunting their growth.

It is believed to be the reason why some larger galaxies like our Milky Way don't have many smaller companion galaxies.

Simulations show that there should be more small galaxies in the Universe, but UV radiation essentially stopped them from developing by depriving them of the gas they need to form stars.

Larger galaxies like the Milky Way were able to withstand this cosmic blast because of the thick gas clouds surrounding them.

Galaxy UGC 7321 is surrounded by hydrogen gas, and as this gas is irradiated with UV radiation, it emits a diffuse red glow through a process known as fluorescence. This image shows the light emitted by stars inside the galaxy, surrounded by a red ring that represents the fluorescent emission induced by the UV radiation.

Credit: M. Fumagalli/T. Theuns/S. Berry

Lead author Dr Michele Fumagalli, in the Institute for Computational Cosmology and Centre for Extragalactic Astronomy, at Durham University, said: "Massive stars and supermassive black holes produce huge amounts of ultraviolet radiation, and their combined radiation builds-up this ultraviolet background.

"This UV radiation excites the gas in the Universe, causing it to emit red light in a similar way that the gas inside a fluorescent bulb is excited to produce visible light.

"Our research means we now have the ability to measure and map this UV radiation which will help us to further refine models of galaxy formation."

Co-author Professor Simon Morris, in the Centre for Extragalactic Astronomy, Durham University, added: "Ultimately this could help us learn more about the evolution of the Universe and why there are so few small galaxies."

Researchers pointed the Multi Unit Spectroscopic Explorer (MUSE), an instrument of the European Southern Observatory's Very-Large Telescope, in Chile, at the galaxy UGC 7321, which lies at a distance of 30 million light years from Earth.

Colour image of the starlight emitted by a nearby spiral galaxy called UGC 7321. Stars in this galaxy lie in a disc, similar to that of our galaxy, the Milky Way. We see this disc nearly perfectly edge-on. Other sources in the image are foreground or background objects (galaxies and stars), unrelated to galaxy UGC 7321.
Credit: M. Fumagalli/T. Theuns/S. Berry

MUSE provides a spectrum, or band of colours, for each pixel in the image allowing the researchers to map the red light produced by the UV radiation illuminating the gas in that galaxy.

The research, funded in the UK by the Science and Technology Facilities Council, could also help scientists predict the temperature of the cosmic gas with more accuracy.

Co-author Professor Tom Theuns, in Durham University's Institute for Computational Cosmology, said: "Ultraviolet radiation heats the cosmic gas to temperatures higher than that of the surface of the Sun.

"Such hot gas will not cool to make stars in small galaxies. This explains why there are so few small galaxies in the Universe, and also why our Milky Way has so few small satellite galaxies."

Contacts and sources:
Leighton Kitson
Durham University

430 Million-Year-Old Lobster-Like’ Fossil Named in Honor of Sir David Attenborough

An international team of scientists led by the University of Leicester has discovered a new 430 million-year-old fossil and has named it in honour of Sir David Attenborough - who grew up on the University campus.

The fossil is described as 'exceptionally well preserved in three-dimensions' - complete with the soft-parts of the animal, such as legs, eyes and very delicate antennae. The fossil has been determined as an ancient crustacean new to science - a distant relative of the living lobsters, shrimps and crabs. There are about 40,000 crustacean species known today.

An international team of scientists led by the University of Leicester has discovered a new 430 million-year-old fossil and has named it in honor of Sir David Attenborough - who grew up on the University campus.

Credit: © Siveter et al

The find comes from volcanic ash deposits that accumulated in a marine setting in what is now Herefordshire in the Welsh Borderland.

Professor David Siveter of the Department of Geology at the University of Leicester made the discovery working alongside researchers from the Universities of Oxford, Imperial College London and Yale, USA.

Professor Siveter said: "Such a well-preserved fossil is exciting, and this particular one is a unique example of its kind in the fossil record, and so we can establish it as a new species of a new genus."

"Even though it is relatively small, at just nine millimetres long, it preserves incredible detail including body parts that are normally not fossilized. It provides scientists with important, novel insights into the evolution of the body plan, the limbs and possible respiratory-circulatory physiology of a primitive member of one of the major groups of Crustacea."

Credit: University Leicester

The fossil is named Cascolus ravitis in honour of Sir David, who grew up on University College Leicester campus (the forerunner of the University), in celebration of his 90th birthday. Cascolus is derived from castrum meaning 'stronghold' and colus, 'dwelling in', alluding to the Old English source for the surname Attenborough; while 'ravitis" is a combination of Ratae - the Roman name for Leicester - 'vita', life, and 'commeatis', a messenger.

Professor Siveter said: "In my youth, David Attenborough's early programmes on the BBC, such as 'Zoo Quest', greatly encouraged my interest in Natural History and it is a pleasure to honour him in this way."

Sir David Attenborough said: "The biggest compliment that a biologist or palaeontologist can pay to another one is to name a fossil in his honour and I take this as a very great compliment. I was once a scientist so I'm very honoured and flattered that the Professor should say such nice things about me now."

Professor Siveter added: "The animal lived in the Silurian period of geological time. Some 430 million years ago much of southern Britain was positioned in warm southerly subtropical latitudes, quite close to a large ancient continent of what we now call North America, and was covered by a shallow sea. The crustacean and other animals living there died and were preserved when a fine volcanic ash rained down upon them."

The fossil specimen has been reconstructed as a virtual fossil by 3D computer modeling.

Contacts and sources:
David Siveter 
University of Leicester

The research is published in the journal Proceedings of the Royal Society B,

Tarnish-Proof Transparent Silver Films for Flexible Displays, Touch Screens, Metamaterials

The thinnest, smoothest layer of silver that can survive air exposure has been laid down at the University of Michigan, and it could change the way touchscreens and flat or flexible displays are made.

It could also help improve computing power, affecting both the transfer of information within a silicon chip and the patterning of the chip itself through metamaterial superlenses.

By combining the silver with a little bit of aluminum, the University of Michigan (U-M researchers found that it was possible to produce exceptionally thin, smooth layers of silver that are resistant to tarnishing. They applied an anti-reflective coating to make one thin metal layer up to )92.4 percent transparent.

University of Michigan researchers have created a transparent silver film that could be used in touchscreens, flexible displays and other advanced applications. L. Jay Guo, professor of electrical engineering and computer science, holds up a piece of the material.
 Image credit: Joseph Xu/Michigan Engineering.

The team showed that the silver coating could guide light about 10 times as far as other metal waveguides—a property that could make it useful for faster computing. And they layered the silver films into a metamaterial hyperlens that could be used to create dense patterns with feature sizes a fraction of what is possible with ordinary ultraviolet methods, on silicon chips, for instance.

Screens of all stripes need transparent electrodes to control which pixels are lit up, but touchscreens are particularly dependent on them. A modern touch screen is made of a transparent conductive layer covered with a nonconductive layer. It senses electrical changes where a conductive object—such as a finger—is pressed against the screen.

"The transparent conductor market has been dominated to this day by one single material," said L. Jay Guo, professor of electrical engineering and computer science.

This material, indium tin oxide, is projected to become expensive as demand for touch screens continues to grow; there are relatively few known sources of indium, Guo said.

"Before, it was very cheap. Now, the price is rising sharply," he said.

The ultrathin film could make silver a worthy successor.

L. Jay Guo, professor of electrical engineering and computer science at the University of Michigan, and Chengang Ji, a doctoral student in the same department, discuss results from a test of a "stainless" silver film that their research group has created.  
Image credit: Joseph Xu/Michigan Engineering

Usually, it's impossible to make a continuous layer of silver less than 15 nanometers thick, or roughly 100 silver atoms. Silver has a tendency to cluster together in small islands rather than extend into an even coating, Guo said.

By adding about 6 percent aluminum, the researchers coaxed the metal into a film of less than half that thickness—seven nanometers. What's more, when they exposed it to air, it didn't immediately tarnish as pure silver films do. After several months, the film maintained its conductive properties and transparency. And it was firmly stuck on, whereas pure silver comes off glass with Scotch tape.

In addition to their potential to serve as transparent conductors for touch screens, the thin silver films offer two more tricks, both having to do with silver's unparalleled ability to transport visible and infrared light waves along its surface. The light waves shrink and travel as so-called surface plasmon polaritons, showing up as oscillations in the concentration of electrons on the silver's surface.

Those oscillations encode the frequency of the light, preserving it so that it can emerge on the other side. While optical fibers can't scale down to the size of copper wires on today's computer chips, plasmonic waveguides could allow information to travel in optical rather than electronic form for faster data transfer. As a waveguide, the smooth silver film could transport the surface plasmons over a centimeter—enough to get by inside a computer chip.

The plasmonic capability of the silver film can also be harnessed in metamaterials, which handle light in ways that break the usual rules of optics. Because the light travels with a much shorter wavelength as it moves along the metal surface, the film alone acts as a superlens. Or, to make out even smaller features, the thin silver layers can be alternated with a dielectric material, such as glass, to make a hyperlens.

Such lenses can image objects that are smaller than the wavelength of light, which would blur in an optical microscope. It can also enable laser patterning—such as is used to etch transistors into silicon chips today—to achieve smaller features.

The first author is Cheng Zhang, a recent U-M doctoral graduate in electrical engineering and computer science who now works as a postdoctoral researcher at National Institute of Standards and Technology.

A paper on this research, titled "High-performance Doped Silver Films: Overcoming Fundamental Material Limits for Nanophotonic Applications" is published in Advanced Materials. The study was supported by the National Science Foundation and the Beijing Institute of Collaborative Innovation. U-M has applied for a patent and is seeking partners to bring the technology to market.

Contacts and sources:
Katherine McAlpine
University of Michigan

Breaking the Supermassive Black Hole Speed Limit

A new computer simulation helps explain the existence of puzzling supermassive black holes observed in the early universe. The simulation is based on a computer code used to understand the coupling of radiation and certain materials.

"Supermassive black holes have a speed limit that governs how fast and how large they can grow," said Joseph Smidt of the Theoretical Design Division at Los Alamos National Laboratory, "The relatively recent discovery of supermassive black holes in the early development of the universe raised a fundamental question, how did they get so big so fast?"

Using computer codes developed at Los Alamos for modeling the interaction of matter and radiation related to the Lab's stockpile stewardship mission, Smidt and colleagues created a simulation of collapsing stars that resulted in supermassive black holes forming in less time than expected, cosmologically speaking, in the first billion years of the universe.

This is a quasar growing under intense accretion streams.

Credit: Los Alamos National Laboratory

"It turns out that while supermassive black holes have a growth speed limit, certain types of massive stars do not," said Smidt. "We asked, what if we could find a place where stars could grow much faster, perhaps to the size of many thousands of suns; could they form supermassive black holes in less time?"

It turns out the Los Alamos computer model not only confirms the possibility of speedy supermassive black hole formation, but also fits many other phenomena of black holes that are routinely observed by astrophysicists. The research shows that the simulated supermassive black holes are also interacting with galaxies in the same way that is observed in nature, including star formation rates, galaxy density profiles, and thermal and ionization rates in gasses.

"This was largely unexpected," said Smidt. "I thought this idea of growing a massive star in a special configuration and forming a black hole with the right kind of masses was something we could approximate, but to see the black hole inducing star formation and driving the dynamics in ways that we've observed in nature was really icing on the cake."

Gravitational collapse of the universe.
Credit: Los Alamos National Laboratory

A key mission area at Los Alamos National Laboratory is understanding how radiation interacts with certain materials. Because supermassive black holes produce huge quantities of hot radiation, their behavior helps test computer codes designed to model the coupling of radiation and matter. The codes are used, along with large- and small-scale experiments, to assure the safety, security, and effectiveness of the U.S. nuclear deterrent.

"We've gotten to a point at Los Alamos," said Smidt, "with the computer codes we're using, the physics understanding, and the supercomputing facilities, that we can do detailed calculations that replicate some of the forces driving the evolution of the Universe."

Contacts  and sources:
Kevin Roark
Los Alamos National Laboratory

Research paper available at https://arxiv.org/pdf/1703.00449.pdf

Mystery of How Sperm Swim Revealed in Mathematical Formula

Researchers have developed a mathematical formula based on the rhythmic movement of a sperm's head and tail, which significantly reduces the complexities of understanding and predicting how sperm make the difficult journey towards fertilising an egg.

Researchers at the Universities of York, Birmingham, Oxford and Kyoto University, Japan, found that the sperm's tail creates a characteristic rhythm that pushes the sperm forward, but also pulls the head backwards and sideways in a coordinated fashion.

Successful fertility relies on how a sperm moves through fluid, but capturing details of this movement is a complicated issue.

Sperm stirs the fluid around in a very coordinated way locomotion, not too dissimilar to the way in which magnetic fields are formed around magnets.
Credit: Kyoto University

The team aim to use these new findings to understand how larger groups of sperm behave and interact, a task that would be impossible using modern observational techniques. The work could provide new insights into treating male infertility.

Dr Hermes Gadêlha, from the University of York's Department of Mathematics, said: "In order to observe, at the microscale, how a sperm achieves forward propulsion through fluid, sophisticated microscopic high precision techniques are currently employed.

"Measurements of the beat of the sperm's tail are fed into a computer model, which then helps to understand the fluid flow patterns that result from this movement.

"Numerical simulations are used to identify the flow around the sperm, but as the structures of the fluid are so complex, the data is particularly challenging to understand and use. Around 55 million spermatozoa are found in a given sample, so it is understandably very difficult to model how they move simultaneously.

"We wanted to create a mathematical formula that would simplify how we address this problem and make it easier to predict how large numbers of sperm swim. This would help us understand why some sperm succeed and others fail."

By analysing the head and tail movements of the sperm, researchers have now shown that the sperm moves the fluid in a coordinated rhythmic way, which can be captured to form a relatively simple mathematical formula. This means complex and expensive computer simulations are no longer needed to understand how the fluid moves as the sperm swim.

The research demonstrated that the sperm has to make multiple contradictory movements, such as moving backwards, in order to propel it forward towards the egg.

The whip-like tail of the sperm has a particular rhythm that pulls the head backwards and sideways to create a jerky fluid flow, countering some of the intense friction that is created due to their diminutive sizes.

Dr Gadêlha said: "It is true when scientists say how miraculous it is that a sperm ever reaches an egg, but the human body has a very sophisticated system of making sure the right cells come together.

"You would assume that the jerky movements of the sperm would have a very random impact on the fluid flow around it, making it even more difficult for competing sperm cells to navigate through it, but in fact you see well defined patterns forming in the fluid around the sperm.

"This suggests that sperm stirs the fluid around in a very coordinated way to achieve locomotion, not too dissimilar to the way in which magnetic fields are formed around magnets. So although the fluid drag makes it very difficult for the sperm to make forward motion, it does coordinate with its rhythmic movements to ensure that only a few selected ones achieve forward propulsion."

Now that the team has a mathematical formula that can predict the fluid movement of one sperm, the next step is to use the model for predictions on larger numbers of cells. They also believe that it will have implications for new innovations in infertility treatment.

The research is published in the journal Physical Review Letters.

Contacts and sources:
Samantha Martin
University of York

Handheld X-Ray Sources May Soon Be a Reality

Electronic oscillations in graphene could make a tabletop—or even handheld— source of X-rays a reality.

Since their discovery in 1895, X-rays have led to significant advances in science, medicine and industry. From probing distant galaxies to screening at airport security and facilitating medical diagnosis, they have allowed us to look beyond the surface and see what lies beneath.

Now, a collaboration between the A*STAR Singapore Institute of Manufacturing Technology (SIMTech) and the Massachusetts Institute of Technology (MIT) in the US has proposed a versatile, directional X-ray source that could fit on a laboratory bench and is based on the intriguing two-dimensional material graphene.

A free electron ‘wiggled’ by graphene plasmons emits an X-ray pulse.
Copyright : A*STAR Singapore Institute of Manufacturing Technology.

X-rays are high-frequency electromagnetic waves that can be generated using X-ray tube technology or from huge sources like synchrotrons and kilometrelong free electron lasers.

But X-ray tube sources, popularly used in medical diagnostics, emit radiation in all directions, wasting a significant amount of the generated X-rays. They are also not ‘tunable’, meaning that a different X-ray source must be installed in a diagnostic device for each desired wavelength.

Kilometre-long free electron lasers, on the other hand, can produce intense, tunable X-rays by accelerating free electrons to extremely high energies and then causing them to ‘wiggle’ using magnets. But these enormous X-ray sources only exist in a few places in the world and are housed in very large, expensive facilities.

An X-ray source that is both small and powerful has been much sought after for some time.

To this end, the team of SIMTech-MIT researchers employed graphene, a oneatom-thick sheet of carbon atoms, which, among other things, can support plasmons: collections of electronic oscillations that can be used to confine and manipulate light on scales of around ten nanometres.

The team first developed a robust simulation tool that models the exact physics of electrons interacting with a plasmon field sustained on a graphene sheet deposited on a piece of 'dielectric’, or insulating, material. By performing numerical simulations, the team showed that this set-up induces a ‘wiggling’ motion in electrons fired through the graphene plasmons, causing the electrons to produce high-frequency X-ray radiation. The simulations agreed with the analytical theory developed by the team to explain how electrons and plasmons interact to produce X-rays.

One standout characteristic of such a source will be its ‘pointability’, which will increase efficiency and hence reduce costs by ensuring that all the generated radiation goes where it’s intended. This will make the source promising for medical treatments as it could be used to target tumours more precisely and hence minimize damage to surrounding organs and cells.

Perhaps most attractive will be the source’s versatility. The output radiation frequency can be tuned in real time from longer infrared rays to shorter X-rays by modifying various elements of the source, such as the speed of the electrons, the frequency of the graphene plasmons and the conductivity of the graphene.

This flexible, compact source is promising as a cost-effective alternative to the high-intensity beams used for fundamental scientific and biomedical research. “Although there is a long way to go to actual realization, this is a very exciting research direction,” says Liang Jie Wong from SIMTech. “Developing an intense X-ray source that can fit on a table or be held in one’s hand would potentially revolutionize many areas of science and technology.”

The team next plans to experimentally verify their concept with proof-of-principle trials.

Contacts and sources:
Dr Liang Jie Wong
Singapore Institute of Manufacturing Technology
Agency for Science, Technology and Research

New Twist on the Sofa Problem That Stumped Mathematicians and Furniture Movers

Most of us have struggled with the mathematical puzzle known as the "moving sofa problem." It poses a deceptively simple question: What is the largest sofa that can pivot around an L-shaped hallway corner?

A mover will tell you to just stand the sofa on end. But imagine the sofa is impossible to lift, squish or tilt. Although it still seems easy to solve, the moving sofa problem has stymied math sleuths for more than 50 years. That's because the challenge for mathematicians is both finding the largest sofa and proving it to be the largest. Without a proof, it's always possible someone will come along with a better solution.

"It's a surprisingly tough problem," said math professor Dan Romik, chair of the Department of Mathematics at UC Davis. "It's so simple you can explain it to a child in five minutes, but no one has found a proof yet.

The Moving Sofa problem asks, what is the largest shape that can move around a right-angled turn? UC Davis mathematician Dan Romik has extended this problem to a hallway with two turns, and shows that a 'bikini top' shaped sofa is the largest so far found that can move down such a hallway.

Romik’s Ambidextrous Sofa is the largest sofa to fit round two turns. It has a sofa constant of 1.64.
Credit; Dan Romik, UC Davis

The largest area that will fit around a corner is called the "sofa constant" (yes, really). It is measured in units where one unit corresponds to the width of the hallway.

Inspired by his passion for 3-D printing, Romik recently tackled a twist on the sofa problem called the ambidextrous moving sofa. In this scenario, the sofa must maneuver around both left and right 90-degree turns. His findings are published online and will appear in the journal Experimental Mathematics.

Eureka Moment

Romik, who specializes in combinatorics, enjoys pondering tough questions about shapes and structures. But it was a hobby that sparked Romik's interest in the moving sofa problem--he wanted to 3-D print a sofa and hallway. "I'm excited by how 3-D technology can be used in math," said Romik, who has a 3-D printer at home. "Having something you can move around with your hands can really help your intuition."

The Gerver sofa is the largest found that will fit round a single turn. It has a “sofa constant” of 2.22 units, where one unit represents the width of the hallway.

Credit: Dan Romik/UC Davis

The Gerver sofa--which resembles an old telephone handset--is the biggest sofa found to date for a one-turn hallway. As Romik tinkered with translating Gerver's equations into something a 3-D printer can understand, he became engrossed in the mathematics underlying Gerver's solution. Romik ended up devoting several months to developing new equations and writing computer code that refined and extended Gerver's ideas. "All this time I did not think I was doing research. I was just playing around," he said. "Then, in January 2016, I had to put this aside for a few months. When I went back to the program in April, I had a lightbulb flash. Maybe the methods I used for the Gerver sofa could be used for something else."

Romik decided to tackle the problem of a hallway with two turns. When tasked with fitting a sofa through the hallway corners, Romik's software spit out a shape resembling a bikini top, with symmetrical curves joined by a narrow center. "I remember sitting in a café when I saw this new shape for the first time," Romik said. "It was such a beautiful moment."

Finding Symmetry

Like the Gerver sofa, Romik's ambidextrous sofa is still only a best guess. But Romik's findings show the question can still lead to new mathematical insights. "Although the moving sofa problem may appear abstract, the solution involves new mathematical techniques that can pave the way to more complex ideas," Romik said. "There's still lots to discover in math."

Contacts and sources:
Andy Fell
University of California Davis

New Non-Toxic Material Generates Electricity Through Hot and Cold, Could Charge Electronics

Thanks to the discovery of a new material by University of Utah engineers, jewelry such as a ring and your body heat could generate enough electricity to power a body sensor, or a cooking pan could charge a cellphone in just a few hours.

The team, led by University of Utah materials science and engineering professor Ashutosh Tiwari, has found that a combination of the chemical elements calcium, cobalt and terbium can create an efficient, inexpensive and bio-friendly material that can generate electricity through a thermoelectric process involving heat and cold air.

Thermoelectric effect is a process where the temperature difference in a material generates an electrical voltage. When one end of the material is hot and the other end is cold, charge carriers from the hot end move through the material to the cold end, generating an electrical voltage. The material needs less than a one-degree difference in temperature to produce a detectable voltage.

University of Utah materials science and engineering professor Ashutosh Tiwari and has team have an inexpensive and bio-friendly material that can generate electricity through a thermoelectric process involving heat and cold air. In this graphic, the heat from a hot stove, coupled with the cooler water or food in a cooking pot, could generate enough electricity to charge a cellphone.

Credit: Ashutosh Tiwari

Their findings were published in a new paper March 20 in the latest issue of Scientific Reports. The first author on the paper is University of Utah materials science and engineering postdoctoral researcher, Shrikant Saini.

For years, researchers have been looking for the right kind of material that makes the process more efficient and produces more electricity yet is not toxic. There are other materials that can generate power this way, such as cadmium-, telluride- or mercury-based materials, but those are toxic to humans. The unique advantage to this new material by Tiwari’s team is that it is inexpensive to produce and, mostly importantly, bio-friendly and eco-friendly while still being efficient at generating electricity, Tiwari says. Therefore, it could be safe to use with humans.

“There are no toxic chemicals involved,” he says. “It’s very efficient and can be used for a lot of day-to-day applications.”

The applications for this new material are endless, Tiwari says. It could be built into jewelry that uses body heat to power implantable medical devices such as blood-glucose monitors or heart monitors. It could be used to charge mobile devices through cooking pans, or in cars where it draws from the heat of the engine. Airplanes could generate extra power by using heat from within the cabin versus the cold air outside. Power plants also could use the material to produce more electricity from the escaped heat the plant generates.

University of Utah materials science and engineering professor Ashutosh Tiwari and his team have an inexpensive and bio-friendly material that can generate electricity through a thermoelectric process involving heat and cold air. The material (the black blocks between the two plates pictured) could be used with cooking pots to charge phones or jewelry to power health sensors.

Credit: Dan Hixson/University of Utah College of Engineering

“In power plants, about 60 percent of energy is wasted,” postdoctoral researcher, Saini, says. “With this, you could reuse some of that 60 percent.”

Finally, Tiwari says it could be used in developing countries where electricity is scarce and the only source of energy is the fire in stoves.

The Technology & Venture Commercialization Office of the University of Utah has filed a U.S. patent for the material, and the team will initially develop it for use in cars and for biosensors, Tiwari says.

In addition to Tiwari and Saini, co-authors on the paper include graduate students Haritha Sree Yaddanapudi, Kun Tian, Yinong Yin and David Magginetti.

Contacts and sources:
 University of Utah