An integrated assessment of vascular plants species of the Americas

Tropical forest.

Missouri Botanical Garden researcher Dr. Carmen Ulloa is the lead author of "An Integrated Assessment of Vascular Plant Species of the Americas," published today in Science. Ulloa along with 23 co-authors compiled a comprehensive, searchable checklist of 124,993 species, 6,227 genera and 355 families of vascular plants of the Americas. This represents one third of all known vascular plants worldwide.

Establishing a checklist like this one has long been a goal of the Garden. In 2015, Ulloa started to research what already existed among existing Garden projects and other botanical institutions across the Americas. She then contacted the editors of the 12 major projects in the last 25 years that served as the basis for this larger checklist including the checklists of Bolivia, Brazil, Colombia, Ecuador, the Guianas, Mexico, Peru, the Southern Cone (Argentina, Chile, Paraguay, Uruguay), Venezuela, and the West Indies. Two partially published datasets of the Flora of North America North of Mexico and the Flora Mesoamericana were also used.

The Garden's plant database, Tropicos® was used as the projects data repository for the project. In the process, more than 25,000 names were added to Tropicos before a final list was compiled.

"This is the first time we have a complete overview of the plants of the Americas," said Ulloa. "It represents not only hundreds of years of plant collecting, and botanical research, but 6,164 botanists who described species that appear on this list. It is vital we have this information so that we know what each species is for conservation purposes."

Co-author Dr. Robert Magill first developed Tropicos in the early 1980s on tiny Osborne 01 microcomputer. Today, it is the world's largest botanical database. It is accessed more 70 million times each year by researchers around the world. It is a link to the past, a digital version of 4.4 million specimens in the Garden's expansive Herbarium. It is also a link to the future, the basis of a larger project, the World Flora Online. The Missouri Botanical Garden and more than 40 other institutions are working to develop the World Flora Online with the goal of documenting all known plant life by 2020.

A number of co-authors are current or former members of the Missouri Botanical Garden research staff including Dr. Gerrit Davidse, Heather Stimmel, Dr. James Zarucchi, Dr. Peter Jørgensen, Magill and Garden President Emeritus Dr. Peter Raven. In addition to this, Dr. Tom Croat and Dr. Charlotte Taylor are both acknowledged in the study's supplemental material for having more than 400 described plant species on the Americas list.

Read more at Science Daily

How odors are turned into long-term memories

Neuroscientists from Bochum have investigated why the brain stores some odours in a special way.

The neuroscientists Dr Christina Strauch and Prof Dr Denise Manahan-Vaughan from the Ruhr-Universität Bochum have investigated which brain area is responsible for storing odours as long-term memories. Some odours can trigger memories of experiences from years back. The current study shows that the piriform cortex, a part of the olfactory brain, is involved in the process of saving those memories; the mechanism, however, only works in interaction with other brain areas. The findings have been published in the journal Cerebral Cortex.

"It is known that the piriform cortex is able to temporarily store olfactory memories. We wanted to know, if that applies to long-term memories as well," says Christina Strauch.

Artificial sensation through stimulation

Synaptic plasticity is responsible for the storing of memories in the memory structures of the brain: During that process the communication between neurons is altered by means of a process called synaptic plasticity, so that a memory is created. Strauch and Manahan-Vaughan examined if the piriform cortex of rats is capable of expressing synaptic plasticity and if this change lasts for more than four hours; indicating that long-term memory may have been established.

The scientists used electrical impulses in the brain to emulate processes that trigger the encoding of an olfactory sensation as a memory. They used different stimulation protocols which varied in the frequency and intensity of the pulses. It is known that these protocols can induce long-term effects in another brain area that is responsible for long term memories: the hippocampus. Strikingly, the same protocols did not induce long-term information storage in the form of synaptic plasticity in the piriform cortex.

Signal from a higher brain area needed

The scientists wondered whether the piriform cortex needs to be instructed to create a long-term memory. They then stimulated a higher brain area called the orbitofrontal cortex, which is responsible for the discrimination of sensory experiences. This time the stimulation of the brain area generated the desired change in the piriform cortex. "Our study shows that the piriform cortex is indeed able to serve as an archive for long-term memories. But it needs instruction from the orbitofrontal cortex -- a higher brain area -- indicating that an event is to be stored as a long-term memory," says Strauch.

From Science Daily

Plants reveal decision-making abilities under competition

The plant Potentilla reptans growing under simulated sparse vegetation.

Biologists from the University of Tübingen have demonstrated that plants can choose between alternative competitive responses according to the stature and densities of their opponents. A new study by researchers from the Institute of Evolution and Ecology reveals that plants can evaluate the competitive ability of their neighbors and optimally match their responses to them. The results were published in Nature Communications.

Animals facing competition have been shown to optimally choose between different behaviors, including confrontation, avoidance and tolerance, depending on the competitive ability of their opponents relative to their own. For example, if their competitors are bigger or stronger, animals are expected to "give up the fight" and choose avoidance or tolerance over confrontation.

Plants can detect the presence of other competing plants through various cues, such as the reduction in light quantity or in the ratio of red to far-red wavelengths (R:FR), which occurs when light is filtered through leaves. Such competition cues are known to induce two types of responses: confrontational vertical elongation, by which plants try to outgrow and shade their neighbors, and shade tolerance, which promotes performance under limited light conditions. Some plants, such as clonal plants, can exhibit avoidance behavior as a third response type: they grow away from their neighbors. "These three alternative responses of plants to light competition have been well-documented in the literature," says Michal Gruntman, lead author of the paper. "In our study we wanted to learn, if plants can choose between these responses and match them to the relative size and density of their opponents."

To answer this question, the researchers used the clonal plant Potentilla reptans in an experimental setup that simulated different light-competition settings. They used vertical stripes of transparent green filters that reduce both light quantity and R:FR and could therefore provide a realistic simulation of light competition. By changing both the height and density of this simulated vegetation, the researchers could present different light-competition scenarios to the plants.

The results demonstrated that Potentilla reptans can indeed choose its response to competition in an optimal way. When the plants were under treatments simulating short-dense neighbors, which presented competitors that where too dense to avoid laterally but could be outgrown vertically, Potentilla reptans showed the highest confrontational vertical growth. However, under simulated tall-dense neighbors, which could not be outgrown either vertically or laterally, plants displayed the highest shade tolerance behavior. Lastly, under tall-sparse neighbors, which could only be avoided laterally, plants exhibited the highest lateral-avoidance behaviors.

Read more at Science Daily

A 508-million-year-old sea predator with a 'jackknife' head

Fossil specimen of Habelia optata from the Royal Ontario Museum. This specimen spectacularly shows some of the very large jaws under the head shield. Note also the long dorsal spines on the thorax.

Paleontologists at the University of Toronto (U of T) and the Royal Ontario Museum (ROM) in Toronto have entirely revisited a tiny yet exceptionally fierce ancient sea creature called Habelia optata that has confounded scientists since it was first discovered more than a century ago.

The research by lead author Cédric Aria, recent graduate of the PhD program in the department of ecology & evolutionary biology in the Faculty of Arts & Science at U of T, and co-author Jean-Bernard Caron, senior curator of invertebrate palaeontology at the ROM and an associate professor in the departments of ecology & evolutionary biology and Earth sciences at U of T, is published today in BMC Evolutionary Biology.

Approximately 2 cm in length with a tail as long as the rest of its body, the long-extinct Habelia optata belongs to the group of invertebrate animals called arthropods, which also includes such familiar creatures as spiders, insects, lobsters and crabs. It lived during the middle Cambrian period approximately 508 million years ago and comes from the renowned Burgess Shale fossil deposit in British Columbia. Habelia optata was part of the "Cambrian explosion," a period of rapid evolutionary change when most major animal groups first emerged in the fossil record.

Like all arthropods, Habelia optata features a segmented body with external skeleton and jointed limbs. What remained unclear for decades, however, was the main sub-group of arthropods to which Habelia belonged. Early studies had mentioned mandibulates -- a hyperdiverse lineage whose members possess antennae and a pair of specialized appendages known as mandibles, usually used to grasp, squeeze and crush their food. But Habelia was later left as one of the typically unresolved arthropods of the Burgess Shale.

The new analysis by the U of T-ROM researchers suggests that Habelia optata was instead a close relative of the ancestor of all chelicerates, the other sub-group of arthropods living today, named for the presence of appendages called chelicerae in front of the mouth and used to cut food. This is mostly due to the overall anatomy of the head in Habelia, and the presence of two small chelicerae-like appendages revealed in these fossils.

"Habelia now shows in great detail the body architecture from which chelicerates emerged, which allows us to solve some long-standing questions," said Aria, who is now a post-doctoral researcher at the Nanjing Institute of Geology and Palaeontology, in China. "We can now explain why, for instance, horseshoe crabs have a reduced pair of limbs -- the chilaria -- at the back of their heads. Those are relics of fully-formed appendages, as chelicerates seem to originally have had heads with no less than seven pairs of limbs."

Aria and Caron analyzed 41 specimens in total, the majority of which are new specimens acquired by ROM-led fieldwork parties to the Burgess Shale.

The research illustrates that the well-armoured body of Habelia optata, covered in a multitude of different spines, was divided into head, thorax and post-thorax, all bearing different types of appendages. The thorax displays five pairs of walking legs, while the post-thorax houses rounded appendages likely used in respiration.

"Scorpions and the now-extinct sea scorpions are also chelicerates with bodies divided into three distinct regions," Aria explained. "We think that these regions broadly correspond to those of Habelia. But a major difference is that scorpions and sea scorpions, like all chelicerates, literally 'walk on their heads,' while Habelia still had walking appendages in its thorax."

The researchers argue that this difference in anatomy allowed Habelia to evolve an especially complex head that makes this fossil species even more peculiar compared to known chelicerates. The head of Habelia contained a series of five appendages made of a large plate with teeth for mastication, a leg-like branch with stiff bristle-like spines for grasping, and an elongate, slender branch modified as a sensory or tactile appendage.

"This complex apparatus of appendages and jaws made Habelia an exceptionally fierce predator for its size," said Aria. "It was likely both very mobile and efficient in tearing apart its preys."

The surprising outcome of this study, despite the evolutionary relationship of Habelia with chelicerates, is that these unusual characteristics led instead the researchers to compare the head of Habelia with that of mandibulates from a functional perspective. Thus, the peculiar sensory branches may have been used in a similar fashion as mandibulates use antennae. Also, the overlapping plate-like appendages in the middle series of five are shown to open and close parallel to the underside of the head -- much as they do in mandibulates, especially those that feed on animals with hardened carapaces.

Lastly, a seventh pair of appendages at the back of the head seems to have fulfilled a function similar to that of "maxillipeds" -- appendages in mandibulates that assist with the other head limbs in the processing of food. This broad correspondence in function rather than in evolutionary origin is called "convergence."

"From an evolutionary point of view, Habelia is close to the point of divergence between chelicerates and mandibulates," Aria said. "But its similarities with mandibulates are secondary modifications of features that were in part already chelicerate in nature. This suggests that chelicerates originated from species with a high structural variability."

The researchers conclude from the outstanding head structure, as well as from well-developed walking legs, that Habelia optata and its relatives were active predators of the Cambrian sea floors, hunting for small shelly sea creatures, such as small trilobites -- arthropods with hard, mineralized exoskeletons that were already very diverse and abundant during Cambrian times.

"This builds onto the importance of carapaces and shells for evolutionary change during the Cambrian explosion, and expands our understanding of ecosystems at this time, showing another level of predator-prey relationship and its determining impact on the rise of arthropods as we know them today," said Caron, who was Aria's PhD supervisor when the bulk of this research was completed.

Read more at Science Daily

Star in the constellation Pisces is 'eating' planets

This illustration shows a "disrupted planet" slowly broken up into a cloud of gas and dust as it orbits the star RZ Piscium about 550 light years from Earth.

Like the ancient Greek god Cronus who devoured his children, a star 550 light years from Earth has been discovered to be slowly consuming its "offspring" -- crushing one or more planets in its orbit into vast clouds of gas and dust.

The discovery that RZ Piscium -- located in the constellation Pisces -- is an insatiable "eater of worlds" was reported today in The Astronomical Journal. Indiana University astronomer Catherine Pilachowski is co-author on the study, titled "Is the Young Star RZ Piscium Consuming Its Own (Planetary) Offspring?"

The discovery may shed light on a brief but volatile period in the history of many solar systems, including our own.

"We know it's not uncommon for planets to migrate inward in young solar systems since we've found so many solar systems with 'hot Jupiters' -- gaseous planets similar in size to Jupiter but orbiting very close to their stars," said Pilachowski, who is the Daniel Kirkwood Chair in the IU Bloomington College of Arts and Sciences' Department of Astronomy. "This is a very interesting phase in the evolution of planetary systems, and we're lucky to catch a solar system in the middle of the process since it happens so quickly compared to the lifetimes of stars."

Doomed worlds that fly too close to their sun -- only to be ripped apart by its tidal forces -- are officially known as "disrupted planets." In the case of RZ Piscium, the material near the sun-like star is being slowly pulled apart to create a small circle of debris about the same distance from the star as the planet Mercury's orbit is from our sun.

"Based on our observations, it seems either that we're seeing a fairly massive, gaseous planet being pulled apart by the star, or perhaps two gas-rich planets that have collided and been torn apart," Pilachowski said of RZ Piscium.

Even solar systems whose planets are not lost to their sun are unstable in their early history, since newly born planets interact strongly with one another -- as well as their sun -- through gravity, she added. In our solar system, for example, some astronomers speculate that Uranus and Neptune swapped orbits about 4 billion years ago. But erratic orbits tend to stabilize over time, falling into regular patterns.

An expert on the analysis of light spectrum from distant stars to determine their temperature, gravity and elemental composition, Pilachowski was responsible in the new study for determining the gravitational strength near RZ Piscium's surface. The observation helped shed light on the star's radius and brightness, both of which suggest a young star in the midst of a freewheeling solar system with unstable planets.

This is significant because RZ Piscium's age was uncertain. The debris field around a star can result from either the erratic orbits in young solar systems or the destruction of planets that occurs as an old star grows before collapsing and dying.

Pilachowski's analysis of the star's light also helped determine the amount of lithium in the star, marking the star as a relatively young 30 million to 50 million years. Astronomers can use lithium levels to estimate a star's age because the element declines over time.

The study's authors also found the star's temperature to be about 9,600 degrees Fahrenheit (5,330 degrees Celsius) -- only slightly cooler than our sun's. Another sign of the star's relative youth: It produces X-rays at a rate roughly 1,000 times greater than our sun.

Read more at Science Daily

The origin of water's unusual properties found

Illustration showing fluctuations between regions of two different local structures (high density as red and low density liquid as blue) of water that depend on the temperature. Maxima in the thermodynamic response and correlation functions are observed as a function of temperature, when the numbers of molecules in the two structures become equal, resulting in strong enhancement in the anomalous properties of water in the deeply supercooled regime.

Using x-ray lasers, researchers at Stockholm University have been able to map out how water fluctuates between two different states when it is cooled. At -44°C these fluctuations reach a maximum pointing to the fact that water can exist as two different distinct liquids. The findings will be published in the journal Science.

Water, both common and necessary for life on earth, behaves very strangely in comparison with other substances. How water's density, specific heat, viscosity and compressibility respond to changes in pressure and temperature is completely opposite to other liquids that we know.

We all are aware that all matter shrinks when it is cooled resulting in an increase in the density. We would therefore expect that water would have high density at the freezing point. However, if we look at a glass of ice water, everything is upside down, since we expect that water at 0°C being surrounded by ice should be at the bottom of the glass, but of course as we know ice cubes float. Strangely enough for the liquid state, water is the densest at 4 degrees C, and therefore it stays on the bottom whether it's in a glass or in an ocean.

If you chill water below 4 degrees, it starts to expand again. If you continue to cool pure water (where the rate of crystallization is low) to below 0, it continues to expand -- the expansion even speeds up when it gets colder. Many more properties such as compressibility and heat capacity become increasingly strange as water is cooled. Now researchers at Stockholm University, with the help of ultra-short x-ray pulses at x-ray lasers in Japan and South Korea, have succeeded in determining that water reaches the peak of its strange behaviour at -44°C.

Water is unique, as it can exist in two liquid states that have different ways of bonding the water molecules together. The water fluctuates between these states as if it can't make up its mind and these fluctuations reach a maximum at -44°C. It is this ability to shift from one liquid state into another that gives water its unusual properties and since the fluctuations increase upon cooling also the strangeness increases.

"What was special was that we were able to X-ray unimaginably fast before the ice froze and could observe how it fluctuated between the two states," says Anders Nilsson, Professor of Chemical Physics at Stockholm University. "For decades there has been speculations and different theories to explain these remarkable properties and why they got stronger when water becomes colder. Now we have found such a maximum, which means that there should also be a critical point at higher pressures."

Another remarkable finding of the study is that the unusual properties are different between normal and heavy water and more enhanced for the lighter one. "The differences between the two isotopes, H2O and D2O, given here shows the importance of nuclear quantum effects," says Kyung Hwan Kim, postdoc in Chemical Physics at Stockholm University. "The possibility to make new discoveries in a much studied topic such as water is totally fascinating and a great inspiration for my further studies," says Alexander Späh, PhD student in Chemical Physics at Stockholm University.

"It was a dream come true to be able to measure water under such low temperature condition without freezing" says Harshad Pathak, postdoc in Chemical Physics at Stockholm University. "Many attempts over the world have been made to look for this maximum."

Read more at Science Daily

An Opioid Vaccine Developed by the US Military Could Combat Addiction

A heroin user prepares to shoot up on the street in a South Bronx neighborhood which has the highest rate of heroin-involved overdose deaths in the city on October 7, 2017 in New York City.

For the first time in a half a century, life expectancy in the United States declined for the second year in a row — and America’s opioid epidemic is to blame. A child born in 2016 is expected to live 78.6 years, down from 78.7 years in 2015 and 78.9 in 2014, according to statistics released by the US Centers for Disease Control and Prevention.

"Two years in a row is quite shocking," Robert Anderson, chief of the mortality statistics branch at the National Center for Health Statistics, told AFP. "The key factor in all this is the increase in drug overdose deaths."

Yet amid the overdose epidemic, another opioid vaccine has shown promising — albeit early — results in the laboratory.

Scientists at the US Military HIV Research Program at the Walter Reed Army Institute of Research (WRAIR) recently developed a vaccine that blocks the opioids in heroin from reaching the brain in mice and rats, offering a potential breakthrough in treating opioid addiction.

When injected, the heroine vaccine releases antibodies into the blood that prohibit the drug from breaking through the blood-brain barrier. This means that even if a heroin addict shoots up, they won’t experience a high. The vaccine includes a potent adjuvant, a substance that boosts the body’s immune response to a toxin, called the Army Liposome Formulation, also developed by researchers at WRAIR.

“All vaccines to substances of abuse function through causing the body to make antibodies that bind the drug of interest and prevent it from entering the brain,” Dr. Gary Matyas, chief of adjuvants and formulations for the US Military Research Program and one of the study authors, told Seeker.

While Matyas and his team have not directly tested their vaccine against vaccines from other research facilities, they have tested it against an older vaccine developed by WRAIR and found that the new one is more effective and very stable. “[Its stability] should increase its shelf-life and keep it from degrading during vaccine manufacturing and storage,” Matyas said.

Their study, published in the Journal of Medicinal Chemistry, found that this new vaccine was not only effective in preventing heroin from reaching the brain but worked with other commonly abused opioids as well, including hydrocodone, oxycodone, hydromorphone, oxymorphone, and codeine. It also lowered the toxic effect of very high doses of heroin, which could be key in preventing overdoses.

The antibodies in the vaccine did not bind to several other opioids like methadone, tramadol, sufentanil, nalbuphine, buprenorphine, and fentanyl. Fentanyl is one of the most widely abused synthetic forms of heroin and 100 times more powerful, which makes it extremely deadly. Due to the high risk of overdose, some researchers have prioritized the development of a treatment method specifically for fentanyl abuse. Along with their heroin vaccine, the Scripps Institute tested a fentanyl vaccine in mice and found it to be similarly effective, but clinical trials are still needed.

The discovery that the WRAIR vaccine does not interfere with opioids like methadone and buprenorphine turned out to be a positive development, as these drugs are often used in current treatment methods for opioid addiction. Because the vaccine’s antibodies do not bind with methadone, buprenorphine, or naltrexone, it can potentially be used in combination with these therapies.

Most importantly, the vaccine did not react with naloxone, which is used in emergency overdose rescue treatments to reverse respiratory complications. And it did not react to non-opioid pain relievers like ibuprofen or aspirin.

While this research is an important advancement in treating opioid addiction, it could be several years before the vaccine is commercially available. “Vaccines typically take many years to develop, test, and manufacture, and we are still in the early stages,” Matyas said. “We are currently pursuing funding for a clinical trial [and] we have licensed the product to Opiant Pharmaceuticals to continue development and manufacture at the appropriate point.”

Administering methadone or buprenorphine is the most common treatment option for heroin addicts, but these methods are often expensive and require inconvenient daily trips to a clinic. What’s more, the chance of relapse afterwards is very high. 91 people die every day from an opioid overdose in the US, according to the CDC. By addressing the issue of relapse due to intense cravings, this new vaccine offers one additional solution for treatment.

The US military’s vaccine, funded by the National Institute of Health, the Henry M. Jackson Foundation for the Advancement of Military Medicine, and the US Army, is not the only one in development. In June, the Scripps Research Institute published their work on a similar vaccine that was found to be effective in mice, as well as rhesus monkeys, and other opioid vaccines are also being developed and tested in order to address the growing epidemic.

Read more at Seeker

Beauty is in the eye of the beer holder

Men under the influence of alcohol are more likely to see women as sexual objects. This is according to a study which moves beyond the mere anecdotal to investigate some of the circumstances and factors that influence why men objectify women. The research is published in Springer's journal Sex Roles and is led by Abigail Riemer of the University of Nebraska-Lincoln in the US.

The study involved 49 men in their twenties and was conducted in the safe space of a college laboratory. Of the 49 subjects, 29 received two alcoholic drinks to mildly intoxicate them, and the rest received placebo drinks. All were shown photographs of 80 undergraduate women dressed to go out, and were asked to rate the women's appearances and personality. The women's photos were previously rated by an independent panel on how much warmth, good-naturedness, friendliness, competence, intelligence, confidence, and attractiveness they exuded. Eye-tracking technology noted which part of the women's bodies men were looking at when they were shown the images.

When the men assessed a photographed woman based on her appearance, the instruction most often triggered objectifying gazes from them. They spent less time looking at faces and focused far longer on chests and waists. This was particularly true when viewing women who had been rated high in attractiveness. It happened to a lesser degree when viewing women who exuded warmth and competence, especially when men were slightly drunk. The findings suggest that whether a man will sexually objectify a woman depends on the alcohol intoxication of the man, as well as how attractive, warm and competent a woman is perceived to be.

"The sum of these results supports the notion that being perceived as high in humanizing attributes, such as warmth and competence, or being average in attractiveness provides a buffer that protects women from sexual objectification," says Riemer.

"Environments in which alcohol is present are ripe with opportunities for objectifying gazes," adds Riemer, who says that the only other study previously done on the link between alcohol and objectification by men relied on self-reports from women. "Adopting objectifying gazes toward women leads perceivers to dehumanize women, potentially laying the foundation for many negative consequences such as sexual violence and workplace gender discrimination."

She hopes findings from the study will help to challenge specific maladaptive beliefs held by some men that it is OK and acceptable to direct objectifying gazes toward women, especially those who are not typically considered to be attractive or who are not perceived as being competent or to have a warm personality.

Read more at Science Daily

North Atlantic Oscillation synchronizes tree reproduction across Europe

Research by the University of Liverpool has found a strong correlation between the North Atlantic Oscillation and synchronised tree reproduction across Europe, supporting the idea that this phenomenon plays a greater role in large scale masting, the process whereby forest trees produce large numbers of seeds in the same year.

The North Atlantic Oscillation (NAO) refers to the large scale changes in pressure that occur naturally in the North Atlantic region. It has been shown to have a strong effect on atmospheric circulation and European climate.

It is known that tree reproduction tends to be strongly synchronised within local populations, so that if one tree is producing a very heavy seed or fruit crop, it is very likely that a neighbouring tree will also be heavily fruiting.

However, in a study, published in Nature Communications researchers analysed tree masting observational data taken over a 190-year period for two key tree species in Europe, European beech and Norway spruce, and compared this to data on the Northern Atlantic Oscillation.

They found that in 1976, 1995 and 2011, both of these species across all of Europe simultaneously produced heavy seed crops.

The researchers found that for the last sixty years continent-wide masting in beech and spruce coincided with high-frequency summer- and spring-NAO and low-frequency winter-NAO. It also reveals a weaker relationship between NAO and masting for the first part of the twentieth century.

Dr Andrew Hacket-Pain, Lecturer in Biogeography and Ecology at the University's Department of Geography and Planning, said: "Our work shows that the remarkable synchronisation of behaviour across such vast distances is linked to the North Atlantic Oscillation.

"We think this is because a strong NAO synchronises climate across large parts of Europe, especially during key phases of the tree reproduction cycle. This helps to synchronise seed crops across such large areas, but future work will be required to firmly establish this mechanism.

"The synchronisation of seed production is important, as it has knock-on effects on forest ecosystems. For example, heavy seed crops increase food availability for woodland-based birds and small animals, and consequently tend to increase the size of such animal populations in the short-term. Additionally, it has implications for human health, as the increase in animal hosts has a positive effect on tick numbers."

Read more at Science Daily

How plants form their seeds

Pollen tubes with internalized, fluorescence-labelled signal substances (RALF peptides).

Around 80 to 85 percent of our calorie needs is covered through seeds, either directly as food or indirectly through use as feed. Seeds are the result of plant reproduction. During the flowering period, the male and female tissues interact with each other in a number of ways. When pollen lands on the flower's stigma, it germinates and forms a pollen tube, which then quickly grows towards the plant's ovary. Once it finds an ovule, the pollen tube bursts to release sperm cells, which fertilize the ovule and initiate seed formation.

Pollen tube interacts with female plant tissue

Led by Ueli Grossniklaus, professor at the Department of Plant and Microbial Biology at the University of Zurich, an international research team has now demonstrated how the pollen tube interacts with, and responds to, female plant tissue. The pollen tube does so by secreting extracellular signals (RALF peptides) which it uses to explore its cellular environment and regulate its growth. Two receptors on the cell's surface enable it to perceive the secreted signals and transmit them to the inside of the cell.

Intracellular signals regulate growth

Working together with the teams of Christoph Ringli from UZH and Jorge Muschietti from the University of Buenos Aires, the team around Grossniklaus was able to determine that further proteins had to be active for the pollen tube to recognize the signals -- LRX proteins. These proteins were identified at UZH 15 years ago by Beat Keller and his research group, but their function had previously not been clear. LRX proteins are localized in the cell wall surrounding plant cells, where the signals can dock. "We suspect that the pollen tube explores changes in the cell wall by sending out signals and responding accordingly, for example by realigning its growth," says Ueli Grossniklaus. It is rare for plants to produce and perceive signals with the same cells. The researchers suspect that this allows the pollen tube, which grows extremely quickly, to faster respond to changes in its environment rather than being dependent on signals from other neighboring cells.

Molecular insights open up wide range of potential applications

The signaling pathways described by the researchers are involved in many other basic processes, and knowledge of how they work opens up numerous possible applications for plant breeding. "By better understanding how these proteins work, we can not only influence pollination and seed formation, but also the development and growth of plants or their defense against pests," concludes Ueli Grossniklaus.

From Science Daily

Radio observations point to likely explanation for neutron-star merger phenomena

A hidden or 'choked' jet (white) powering a radio-emitting 'cocoon' (pink) is the best explanation for the radio waves, gamma rays and X-rays the astronomers observed.

Three months of observations with the National Science Foundation's Karl G. Jansky Very Large Array (VLA) have allowed astronomers to zero in on the most likely explanation for what happened in the aftermath of the violent collision of a pair of neutron stars in a galaxy 130 million light-years from Earth. What they learned means that astronomers will be able to see and study many more such collisions.

On August 17, 2017, the LIGO and VIRGO gravitational-wave observatories combined to locate the faint ripples in spacetime caused by the merger of two superdense neutron stars. It was the first confirmed detection of such a merger and only the fifth direct detection ever of gravitational waves, predicted more than a century ago by Albert Einstein.

The gravitational waves were followed by outbursts of gamma rays, X-rays, and visible light from the event. The VLA detected the first radio waves coming from the event on September 2. This was the first time any astronomical object had been seen with both gravitational waves and electromagnetic waves.

The timing and strength of the electromagnetic radiation at different wavelengths provided scientists with clues about the nature of the phenomena created by the initial neutron-star collision. Prior to the August event, theorists had proposed several ideas -- theoretical models -- about these phenomena. As the first such collision to be positively identified, the August event provided the first opportunity to compare predictions of the models to actual observations.

Astronomers using the VLA, along with the Australia Telescope Compact Array and the Giant Metrewave Radio Telescope in India, regularly observed the object from September onward. The radio telescopes showed the radio emission steadily gaining strength. Based on this, the astronomers identified the most likely scenario for the merger's aftermath.

"The gradual brightening of the radio signal indicates we are seeing a wide-angle outflow of material, traveling at speeds comparable to the speed of light, from the neutron star merger," said Kunal Mooley, now a National Radio Astronomy Observatory (NRAO) Jansky Postdoctoral Fellow hosted by Caltech.

The observed measurements are helping the astronomers figure out the sequence of events triggered by the collision of the neutron stars.

The initial merger of the two superdense objects caused an explosion, called a kilonova, that propelled a spherical shell of debris outward. The neutron stars collapsed into a remnant, possibly a black hole, whose powerful gravity began pulling material toward it. That material formed a rapidly-spinning disk that generated a pair of narrow, superfast jets of material flowing outward from its poles.

If one of the jets were pointed directly toward Earth, we would have seen a short-duration gamma-ray burst, like many seen before, the scientists said.

"That clearly was not the case," Mooley said.

Some of the early measurements of the August event suggested instead that one of the jets may have been pointed slightly away from Earth. This model would explain the fact that the radio and X-ray emission were seen only some time after the collision.

"That simple model -- of a jet with no structure (a so-called top-hat jet) seen off-axis -- would have the radio and X-ray emission slowly getting weaker. As we watched the radio emission strengthening, we realized that the explanation required a different model," said Alessandra Corsi, of Texas Tech University.

The astronomers looked to a model published in October by Mansi Kasliwal of Caltech, and colleagues, and further developed by Ore Gottlieb, of Tel Aviv University, and his colleagues. In that model, the jet does not make its way out of the sphere of explosion debris. Instead, it gathers up surrounding material as it moves outward, producing a broad "cocoon" that absorbs the jet's energy.

The astronomers favored this scenario based on the information they gathered from using the radio telescopes. Soon after the initial observations of the merger site, the Earth's annual trip around the Sun placed the object too close to the Sun in the sky for X-ray and visible-light telescopes to observe. For weeks, the radio telescopes were the only way to continue gathering data about the event.

"If the radio waves and X-rays both are coming from an expanding cocoon, we realized that our radio measurements meant that, when NASA's Chandra X-ray Observatory could observe once again, it would find the X-rays, like the radio waves, had increased in strength," Corsi said.

Mooley and his colleagues posted a paper with their radio measurements, their favored scenario for the event, and this prediction online on November 30. Chandra was scheduled to observe the object on December 2 and 6.

"On December 7, the Chandra results came out, and the X-ray emission had brightened just as we predicted," said Gregg Hallinan, of Caltech.

"The agreement between the radio and X-ray data suggests that the X-rays are originating from the same outflow that's producing the radio waves," Mooley said.

Read more at Science Daily

Bad Breath Can Be Caused and Passed on Through a Genetic Mutation

About 90 percent of all bad breath cases originate in the mouth. Triggers could be as innocuous as consumption of a pizza covered in garlic or biting into a savory burger with raw onions. Tooth brushing and a swish of mouthwash usually remove the smells and also help to prevent odor-causing decay.

The other approximately 10 percent of halitosis bouts are considered to be extra-oral, arising internally from conditions affecting the nose, sinuses, tonsils, esophagus, or blood. These may include infections, diabetes, stomach disorders, or taking certain medications.

New research finds yet another cause to add to the list: People may inherit a genetic mutation that leads to perpetual bad breath. The study, published in the journal Nature Genetics, is the first to link a genetic defect to halitosis.

Co-author Edwin Winkel of the University of Groningen and the Clinic for Periodontology in Amsterdam told Seeker: “Extra-oral halitosis is always present since the odor comes from the blood via the lungs into the breath, while the oral form is caused by bacteria in the oral cavity."

Certain food components, such as the sulfuric compounds allyl methyl sulfide in garlic and methyl propyl sulfide in onions, contribute to halitosis, he added.

Strains of the bacterium Hyphomicrobium

The origins of the study go back 25 years, when a Dutch woman with smelly, never-ending bad breath visited Winkel's dental practice. The woman said her brother had the same halitosis problem.

Winkel obtained body fluid samples from the patient and sent them to Radboud University Nijmegen Medical Center for analysis. Albert Tangerman, Ron Wevers, and their colleagues found abnormally high concentrations of 4 sulfur-containing metabolites in the samples.

Two of the four are the volatile compounds dimethyl sulfide and methanethiol, which can originate from food and are produced in large amounts in the intestines. It is little wonder that the patient releasing these metabolites had bad breath.

"The odor of methanethiol is described as 'a distinctive putrid smell' and is also part of the smell of human flatus and of French cheese," co-author Huub Op den Camp of Radboud told Seeker. "The smell of dimethylsulfide resembles that released when cooking cauliflower or cabbage."

Op den Camp specializes in the ecology and physiology of microorganisms. He, along with colleagues, next investigated bacteria that break down methanethiol. They discovered a protein, methanethiol oxidase, in the bacterium Hyphomicrobium that does so. The bacterium feeds on contamination in sewage, including sulfur compounds like methanethiol.

"Since we knew the genome of this bacterium, we were able to identify the gene" that encodes the methanethiol oxidase, Op den Camp told Seeker. "The next step was the exciting discovery that humans have an identical gene in their genome."

Op den Camp, lead author Arjan Pol, and their team achieved this latest feat after Wevers asked various colleagues from around the world if they knew of patients with chronic halitosis and especially if the bad breath seemed to affect multiple members of the same family. This led to the identification of three such families: a family in Germany, a Portuguese family, and a Dutch family. 

The scientists took breath, blood, and urine from the patients, and determined that all had mutations in the SELENBP1 gene that encodes selenium-binding protein 1, which — as predicted — was found to be a methanethiol oxidase. Individuals harboring the mutation therefore cannot properly break down methanethiol, leading to the malodorous breath.

"In all patients, one of the mutations was maternally inherited and the other came from the father," Wevers said. "In the end, it will turn out that there will be equal numbers of males and females affected."

The mutation may even be more common than presently believed. The researchers calculate that about 1 in 90,000 people carry the mutation. For those who inherit the halitosis disorder, there is no cure, but they are advised to watch their diets to avoid foods that may further worsen the smell of their breath.

The halitosis perhaps affects nearby non-family members more than the patients themselves, since, as Wevers said: "They are used to having this smell around." It also does not seem to hurt their ability to taste food.

A far more worrisome health issue came to the forefront during the research on bad breath, however.

Prior studies have found that SELENBP1 is a possible biomarker for disease progression in several cancers, such as those affecting the breasts, kidney, and colon. Additionally, methanethiol and dimethylsulfide have been identified in numerous of cancers.

"We think that this is the reason dogs can smell cancer, because both metabolites have been found in several cancer types," Wevers said. "Humans can certainly smell each of these, but the dog's nose is simply much better at that."

Read more at Seeker

Easter Island had a cooperative community, analysis of giant hats reveals

Pukao are large, cylindrical stones made from a volcanic rock known as 'red scoria.' Weighing multiple tons, they were placed on the heads of the moai during prehistoric times, consistent with the Polynesian traditions of honoring their ancestors.

Analysis of giant stone hats found on Rapa Nui, Chile (Easter Island) provides evidence contrary to the widely held belief that the ancient civilization had a warrior culture. According to a new study conducted by a team of researchers, including a professor at Binghamton University, State University of New York, these stone hats suggest that the people of Rapa Nui were part of a supportive and inclusive community.

Carl Lipo, anthropology professor and director of the Environmental Studies Program at Binghamton University, and a team of researchers studied the monumental statues (moai) on Rapa Nui, and the previously unacknowledged giant stone hats (pukao) that were placed atop them. Pukao are large, cylindrical stones made from a volcanic rock known as 'red scoria.' Weighing multiple tons, they were placed on the heads of the moai during prehistoric times, consistent with the Polynesian traditions of honoring their ancestors.

The researchers produced the first study analyzing the pukao and their significance, examining the 70 multi-ton giant hats scattered around the island that have gradually eroded over time. Using photography to produce 3D computer models, the researchers were able to study the pukao in greater detail and discovered that there are far more drawings carved into the hats than was previously thought.

"With the building mitigating any sense of conflict, the moai construction and pukao placement were key parts to the success of the island," said Lipo. "In our analysis of the archaeological records, we see evidence that demonstrates the prehistoric communities repeatedly worked together to build monuments. The action of cooperation had a benefit to the community by enabling sharing of information and resources."

While Easter Island is famous, the archaeological record of the island is not well-documented, said Lipo. He believes that scientists can learn a great deal from the pukao by examining this new information.

Read more at Science Daily

Life on the ice: For the first time scientists have directly observed living bacteria in polar ice and snow

The research team positioned themselves away from polar wildlife to limit contamination, but one persistently curious character meant a testing site had to be abandoned.

For the first time scientists have directly observed living bacteria in polar ice and snow -- an environment once considered sterile. The new evidence has the potential to alter perceptions about which planets in the universe could sustain life and may mean that humans are having an even greater impact on levels of CO2 in Earth's atmosphere than accepted evidence from climate history studies of ice cores suggests.

Gases captured and sealed in snow as it compresses into ice can provide researchers with snapshots of Earth's atmosphere going back hundreds of thousands of years. Climate scientists use ice core samples to look at prehistoric levels of CO2 in the atmosphere so they can be compared with current levels in an industrial age.

This analysis of ice cores relies on the assumption that there is limited biological activity altering the environment in the snow during its transition into ice. Research reported in the Journal of the Royal Society Interface, which has directly observed microbial activity in Antarctic and Arctic snow, has revealed that the composition of these small samples of gas trapped in the ice may have been affected by bacteria that remain active in snow while it is being compressed into ice -- a process that can last decades.

Lead author of the research Dr Kelly Redeker from the Department of Biology at the University of York said "As microbial activity and its influence on its local environment has never been taken into account when looking at ice-core gas samples it could provide a moderate source of error in climate history interpretations. Respiration by bacteria may have slightly increased levels of CO2 in pockets of air trapped within polar ice caps meaning that before human activity CO2 levels may have been even lower than previously thought."

"In addition, the fact that we have observed metabolically active bacteria in the most pristine ice and snow is a sign of life proliferating in environments where you wouldn't expect it to exist. This suggests we may be able to broaden our horizons when it comes to thinking about which planets are capable of sustaining life," Redeker added.

Research conducted in laboratories has previously shown that bacteria can stay alive at extremely cold temperatures, but this study is the first time that bacteria have been observed altering the polar snow environment in situ.

The researchers looked at snow in is natural state, and in other areas they sterilised it using UV sterilising lamps. When they compared the results the team found unexpected levels of methyl iodide -- a gas known to be produced by marine bacteria -- in the untouched snow.

Cutting-edge techniques enabled the researchers to detect the presence of gases even at part-per-trillion levels, one million times less concentrated than atmospheric CO2 concentrations.

The researchers worked on sites in the Arctic and Antarctic and took precautions to limit the impact of sunlight and wind, using tarpaulins to protect their sample sites and positioning themselves on the middle of a glacier away from soil and other forms of polar wildlife which might contaminate the snow.

The results of the study also suggest that life can be sustained even in remote, cold, nutrient poor environments, offering a new perspective on whether the frozen planets of the universe could support microorganisms.

With more research, astrobiologists working to identify planets in the universe with temperature levels that could allow for the presence of liquid water may be able to expand the zones they consider potentially habitable to include planets where water is found as ice.

Read more at Science Daily

Mars: Not as dry as it seems

This is image shows modern Mars (left) dry and barren, compared with the same scene over 3.5 billion years ago covered in water (right). The rocks of the surface were slowly reacting with the water, sequestering it into the Martian mantle leading to the dry, inhospitable scene shown on the left.

When searching for life, scientists first look for an element key to sustaining it: fresh water.

Although today's Martian surface is barren, frozen and inhabitable, a trail of evidence points to a once warmer, wetter planet, where water flowed freely. The conundrum of what happened to this water is long standing and unsolved. However, new research published in Nature suggests that this water is now locked in the Martian rocks.

Scientists at Oxford's Department of Earth Sciences, propose that the Martian surface reacted with the water and then absorbed it, increasing the rocks oxidation in the process, making the planet uninhabitable.

Previous research has suggested that the majority of the water was lost to space as a result of the collapse of the planet's magnetic field, when it was either swept away by high intensity solar winds or locked up as sub-surface ice. However, these theories do not explain where all of the water has gone.

Convinced that the planet's minerology held the answer to this puzzling question, a team led by Dr Jon Wade, NERC Research Fellow in Oxford's Department of Earth Sciences, applied modelling methods used to understand the composition of Earth rocks to calculate how much water could be removed from the Martian surface through reactions with rock. The team assessed the role that rock temperature, sub-surface pressure and general Martian make-up, have on the planetary surfaces.

The results revealed that the basalt rocks on Mars can hold approximately 25 per cent more water than those on Earth, and as a result drew the water from the Martian surface into its interior.

Dr Wade said: 'People have thought about this question for a long time, but never tested the theory of the water being absorbed as a result of simple rock reactions. There are pockets of evidence that together, leads us to believe that a different reaction is needed to oxidise the Martian mantle. For instance, Martian meteorites are chemically reduced compared to the surface rocks, and compositionally look very different. One reason for this, and why Mars lost all of its water, could be in its minerology.

'The Earth's current system of plate tectonics prevents drastic changes in surface water levels, with wet rocks efficiently dehydrating before they enter the Earth's relatively dry mantle. But neither early Earth nor Mars had this system of recycling water. On Mars, (water reacting with the freshly erupted lavas' that form its basaltic crust, resulted in a sponge-like effect. The planet's water then reacted with the rocks to form a variety of water bearing minerals. This water-rock reaction changed the rock mineralogy and caused the planetary surface to dry and become inhospitable to life.'

As to the question of why Earth has never experienced these changes, he said: 'Mars is much smaller than Earth, with a different temperature profile and higher iron content of its silicate mantle. These are only subtle distinctions but they cause significant effects that, over time, add up. They made the surface of Mars more prone to reaction with surface water and able to form minerals that contain water. Because of these factors the planet's geological chemistry naturally drags water down into the mantle, whereas on early Earth hydrated rocks tended to float until they dehydrate.'

The overarching message of Dr Wade's paper, that planetary composition sets the tone for future habitability, is echoed in new research also published in Nature, examining the Earth's salt levels. Co-written by Professor Chris Ballentine of Oxford's Department of Earth Sciences, the research reveals that for life to form and be sustainable, the Earth's halogen levels (Chlorine, Bromine and Iodine) have to be just right. Too much or too little could cause sterilisation. Previous studies have suggested that halogen level estimates in meteorites were too high. Compared to samples of the meteorites that formed the Earth, the ratio of salt to Earth is just too high.

Many theories have been put forward to explain the mystery of how this variation occurred, however, the two studies combined elevate the evidence and support a case for further investigation. Dr Wade said 'Broadly speaking the inner planets in the solar system have similar composition, but subtle differences can cause dramatic differences -- for example, rock chemistry. The biggest difference being, that Mars has more iron in its mantle rocks, as the planet formed under marginally more oxidising conditions.'

We know that Mars once had water, and the potential to sustain life, but by comparison little is known about the other planets, and the team are keen to change that.

Dr Wade, said: 'To build on this work we want to test the effects of other sensitivities across the planets -- very little is known about Venus for example. Questions like: what if the Earth had more or less iron in the mantle, how would that change the environment? What if the Earth was bigger or smaller? These answers will help us to understand how much of a role rock chemistry determines a planet's future fate.

Read more at Science Daily

Origins of photosynthesis in plants dated to 1.25 billion years ago

The Angmaat Formation above Tremblay Sound on the Baffin Island coast. Bangiomorpha pubescens fossils occur in this roughly 500-meter thick rock formation.

The world's oldest algae fossils are a billion years old, according to a new analysis by earth scientists at McGill University. Based on this finding, the researchers also estimate that the basis for photosynthesis in today's plants was set in place 1.25 billion years ago.

The study, published in the journal Geology, could resolve a long-standing mystery over the age of the fossilized algae, Bangiomorpha pubescens, which were first discovered in rocks in Arctic Canada in 1990. The microscopic organism is believed to be the oldest known direct ancestor of modern plants and animals, but its age was only poorly dated, with estimates placing it somewhere between 720 million and 1.2 billion years.

The new findings also add to recent evidence that an interval of Earth's history often referred to as the Boring Billion may not have been so boring, after all. From 1.8 to 0.8 billion years ago, archaea, bacteria and a handful of complex organisms that have since gone extinct milled about the planet's oceans, with little biological or environmental change to show for it. Or so it seemed. In fact, that era may have set the stage for the proliferation of more complex life forms that culminated 541 million years ago with the so-called Cambrian Explosion.

"Evidence is beginning to build to suggest that Earth's biosphere and its environment in the latter portion of the 'Boring Billion' may actually have been more dynamic than previously thought," says McGill PhD student Timothy Gibson, lead author of the new study.

Pinpointing the fossils' age

To pinpoint the fossils' age, the researchers pitched camp in a rugged area of remote Baffin Island, where Bangiomorpha pubescens fossils have been found There,despite the occasional August blizzard and tent-collapsing winds, they collected samples of black shale from rock layers that sandwiched the rock unit containing fossils of the alga. Using the Rhenium-Osmium (or Re-Os) dating technique, applied increasingly to sedimentary rocks in recent years, they determined that the rocks are 1.047 billion years old.

"That's 150 million years younger than commonly held estimates, and confirms that this fossil is spectacular," says Galen Halverson, senior author of the study and an associate professor in McGill's Department of Earth and Planetary Sciences. "This will enable scientists to make more precise assessments of the early evolution of eukaryotes," the celled organisms that include plants and animals.

Because Bangiomorpha pubescens is nearly identical to modern red algae, scientists have previously determined that the ancient alga, like green plants, used sunlight to synthesize nutrients from carbon dioxide and water. Scientists have also established that the chloroplast, the structure in plant cells that is the site of photosynthesis, was created when a eukaryote long ago engulfed a simple bacterium that was photosynthetic. The eukaryote then managed to pass that DNA along to its descendants, including the plants and trees that produce most of the world's biomass today.

Origins of the chloroplast

Once the researchers had gauged the fossils' age at 1.047 billion years, they plugged that figure into a "molecular clock," a computer model used to calculate evolutionary events based on rates of genetic mutations. Their conclusion: the chloroplast must have been incorporated into eukaryotes roughly 1.25 billion years ago.

Read more at Science Daily

Giant bubbles on red giant star's surface

Astronomers using ESO's Very Large Telescope have directly observed granulation patterns on the surface of a star outside the Solar System -- the ageing red giant ?1 Gruis. This remarkable new image from the PIONIER instrument reveals the convective cells that make up the surface of this huge star. Each cell covers more than a quarter of the star's diameter and measures about 120 million kilometres across.

Astronomers using ESO's Very Large Telescope have for the first time directly observed granulation patterns on the surface of a star outside the Solar System -- the ageing red giant π1 Gruis. This remarkable new image from the PIONIER instrument reveals the convective cells that make up the surface of this huge star, which has 350 times the diameter of the Sun. Each cell covers more than a quarter of the star's diameter and measures about 120 million kilometres across. These new results are being published this week in the journal Nature.

Located 530 light-years from Earth in the constellation of Grus (The Crane), π1 Gruis is a cool red giant. It has about the same mass as our Sun, but is 350 times larger and several thousand times as bright. Our Sun will swell to become a similar red giant star in about five billion years.

An international team of astronomers led by Claudia Paladini (ESO) used the PIONIER instrument on ESO's Very Large Telescope to observe π1 Gruis in greater detail than ever before. They found that the surface of this red giant has just a few convective cells, or granules, that are each about 120 million kilometres across -- about a quarter of the star's diameter. Just one of these granules would extend from the Sun to beyond Venus. The surfaces -- known as photospheres -- of many giant stars are obscured by dust, which hinders observations. However, in the case of π1 Gruis, although dust is present far from the star, it does not have a significant effect on the new infrared observations.

When π1 Gruis ran out of hydrogen to burn long ago, this ancient star ceased the first stage of its nuclear fusion programme. It shrank as it ran out of energy, causing it to heat up to over 100 million degrees. These extreme temperatures fueled the star's next phase as it began to fuse helium into heavier atoms such as carbon and oxygen. This intensely hot core then expelled the star's outer layers, causing it to balloon to hundreds of times larger than its original size. The star we see today is a variable red giant. Until now, the surface of one of these stars has never before been imaged in detail.

By comparison, the Sun's photosphere contains about two million convective cells, with typical diameters of just 1500 kilometres. The vast size differences in the convective cells of these two stars can be explained in part by their varying surface gravities. π1 Gruis is just 1.5 times the mass of the Sun but much larger, resulting in a much lower surface gravity and just a few, extremely large, granules.

Read more at Science Daily

Are bones discovered under an Exeter street from the first turkey dinner in England?

Malene Lauritsen with turkey bones.

Bones dug up from under an Exeter street may be the remains of the first ever turkey dinner in England, archaeologists believe.

The 16th century bones -- two femurs (thigh bones) and an ulna (wing) -- have been analysed by University of Exeter archaeologists and identified as among some the first turkeys to be brought to England from the Americas. The bones are on display at the Royal Albert Memorial Museum & Art Gallery (RAMM) where Spanish, German and Italian pottery and glassware from the same site are also displayed. These items could have been on the table when the turkey dinner was served. The first turkeys were introduced to England in 1524 or 1526 by William Strickland, a member of Parliament in the reign of Elizabeth the first, following a voyage to the Americas.

Strickland is recorded to have bought six turkeys from Native American traders, and after he sailed back with them to Bristol, which is 80 miles away from Exeter, sold them for tuppence each.

When turkeys first appeared in England they would have been a rare sight and the first ones are more likely to have been kept as pets for display of wealth rather than served as food.

The bird became very popular after 1550 and already a common sight at Christmas dinners by the 1570s, before Thanksgiving in America was even invented. Popular history even suggests that Henry VIII may have had turkey for Christmas. The bird became so popular that thousands of turkeys were driven in to London like cattle in the 17th century.

The bones were found in 1983 as part of excavations at Paul Street, in central Exeter, before the building of a shopping centre but have never been identified or dated. Archaeologists at the University of Exeter have now examined the bones and judging from pottery lying beside them, they date from the period 1520 to 1550.

Professor Alan Outram, zooarchaeologist and Head of Archaeology at Exeter, said: "As the date of these bones overlaps with the historical evidence of Stickland's introduction of the birds, the remains of this feast may well represent the earliest physical evidence for a turkey dinner in Britain. This is an important discovery and could allow more research to be carried out about early domestic breeds and how the turkey has changed genetically since the 16th century."

Analysis by Malene Lauritsen, a post-graduate researcher in the University of Exeter's archaeology department, has proved from the bones that the turkeys were butchered and were probably eaten as part of a feast by wealthy people. The pottery lying alongside was also of high quality.

They were found together with the remains of a veal calf, several chickens, at least one goose and a sheep. This selection of food -- some of which were very expensive at the time -- suggests this was the rubbish created by a feast attended by people of high status.

"What is exciting about these turkey bones found in Exeter is that they date from almost exactly the same time as the first birds came to England. Their age certainly means it is possible that these are the remains of one of the first turkeys to come to England, or a turkey bred from this group," Ms Lauritsen said.

"It is extremely rare to find turkey bones from this period. Remains from the first half of the 16th century have only been found in two other sites in Britain, the oldest from at St Alban's Abbey in Hertfordshire. I have found cut marks on the bones, showing the birds were butchered. We can only guess at who ate them, and for what reason, but turkey would have been very expensive and the same household certainly ate other pricy meat too, so this must have been a special occasion."

Wild turkeys were eaten by native Americans and their feathers were also used for ceremonial purposes, including headdresses and robes.

They were first brought to Britain from America by William Strickland, a Puritan, who traded them with Native Americans. He continued to import them and made so much money, he was able to build a stately home in Yorkshire.

Strickland, who became an MP and was known for his ferocious debating style, adopted the turkey as the symbol on his family crest in 1550. His coat of arms is reported to be the first depiction of the turkey in Britain. The village church where Strickland is buried has images of turkeys depicted in stained-glass windows, a carved lectern and even stone sculptures on the walls. The bones found during excavations at Paul street, in central Exeter, have been stored in boxes in the Royal Albert Memorial Museum's stores, and are on temporary display.

The bones are part of the collections at RAMM, and are on temporary display to celebrate the new discovery about their origins. In February 2020, the bones will be displayed in RAMM's Making History Gallery alongside all the discoveries made from a wider archaeological research project with the University of Exeter called "Exeter: A Place in Time."

RAMM Assistant Curator Tom Cadbury said: "This is a fascinating discovery and really shows what an international place Tudor Exeter was. RAMM already displays some of the Spanish, German and Italian pottery and glassware found on the site, perhaps the turkey dinner was eaten off one of these. RAMM welcomes research on the archaeological finds from Exeter in the museum; evidence such as this helps us uncover stories about the lives of past people in Exeter."

Read more at Science Daily

More complex biological systems evolve more freely

First author Mato Lagator analyzes the phenotype of a sample of E. coli mutants.

Our genes (aka. the genotype) determine our characteristics (aka. the phenotype). Evolution acts on changes in the phenotype, which occur when mutations change the underlying genotype. But what changes to the phenotype can be produced by mutations is not without bounds -- ants cannot suddenly grow a trunk, or become the size of an elephant. Researchers at the Institute of Science and Technology Austria (IST Austria) found that in a gene regulatory system in the bacterium Escherichia coli, the more components that are mutated, the more freely the system can evolve. This is the result of a study published by a team led by Calin Guet and Jonathan Bollback, with first author postdoc Mato Lagator, in eLife.

Freedom to change

The effects of mutations define how a system can change. But when we take a system composed of several components, such as a system that regulates gene expression, what happens when not only a single component is mutated, but several? Does the system have fewer options for change, or more? The researchers studied this question in a small gene regulatory system in E. coli that consists of two components: a transcription factor, which is a protein that controls the rate of transcription of genetic information from DNA to RNA; and its binding site on the DNA, where the transcription factor binds to start transcription. In this study, the scientists looked at what happens when they mutate each component on its own, and when they mutate both components at the same time.

Somewhat counterintuitively, they found that the system's evolution is less limited when more components are mutated. "In stark contrast to what I assumed prior to conducting the experiments, if we mutate several components, the system can evolve more freely. This came as quite a surprise to me!" says first author Mato Lagator. The team then looked at why the system can evolve in more directions, compared to its individual components.

When 1+1 does not equal 2

They found that the system evolves more freely because mutations in the two components interact with each other, a phenomenon they call "intermolecular epistasis." Mato Lagator explains its significance: "Epistasis means that 1+1 does not equal 2, but 3 or 0. Genetically speaking, one point mutation changes the transcription factor so that the phenotype of our gene regulatory system changes by X, and the other point mutation changes the binding site so that the phenotype changes by Y. Now, when both mutations occur together, the phenotype is not simply X+Y, it is different." This means that mutations interact, giving the whole system more freedom to change and evolve.

So far, our understanding of epistasis has mostly been descriptive, but how the existing molecular mechanisms define the patterns of epistasis has not been understood. In this study, the researchers give a mechanistic understanding of how the mutations in two different molecules interact, explains Mato Lagator: "Most excitingly, we show that -- in this gene regulatory system -- most of the epistasis arises from the genetic structure of the system. This structure determines how the mutations interact with each other."

From Science Daily

Treasure trove of highly detailed fossils uncovered

Microscopic animal fossils. From left; the oldest known pterobranch hemichordate; teeth from a priapulid, a sediment dwelling predatory worm; the carapace of a tiny arthropod.

A team of researchers from Uppsala University have uncovered a hidden diversity of microscopic animal fossils from over half a billion years ago lurking in rocks from the northern tip of Greenland.

The 'Cambrian explosion' of animal diversity beginning ~541 million years ago is a defining episode in the history of life. This was a time when the seas first teemed with animal life, and the first recognisably 'modern' ecosystems began to take shape.

Current accounts of this explosion in animal diversity rely heavily on records from fossilised shells and other hard parts, since these structures are the most likely to survive as fossils.

However, since most marine animals are 'soft-bodied' this represents only a small fraction of the total diversity.

Rare sites of exceptional fossilisation, like the world-famous Burgess Shale, have revolutionised palaeontologists understanding of 'soft-bodied' Cambrian life. Because of the special conditions of fossilisation at these localities, organisms that did not produce hard mineralized shells or skeletons are also preserved. Such sites offer a rare glimpse into the true diversity of these ancient seas, which were filled with a dazzling array of soft and squishy predatory worms and arthropods (the group containing modern crustaceans and insects).

One of the oldest of these truly exceptional fossil bonanzas is the Sirius Passet site in the far north of Greenland. Unfortunately, during their long history, the rocks at Sirius Passet have been heated up and baked to high temperatures as the northern margin of Greenland smashed into various tectonic plates and buried these rocks deep beneath the surface.

All this heating has boiled away the delicate organic remains that once formed the fossils of soft bodied animals at Sirius Passet, leaving only faint impressions of their remains.

Not far to the south of Sirius Passet, the rocks have escaped the worst effects of this heating. A team of palaeontologists from Uppsala (Ben Slater, Sebastian Willman, Graham Budd and John Peel) used a low-manipulation acid extraction procedure to dissolve some of these less intensively cooked mudrocks. To their astonishment, this simple preparation technique revealed a wealth of previously unknown microscopic animal fossils preserved in spectacular detail.

Most of the fossils were less than a millimetre long and had to be studied under the microscope. Fossils at the nearby Sirius Passet site typically preserve much larger animals, so the new finds fill an important gap in our knowledge of the small-scale animals that probably made up the majority of these ecosystems. Among the discoveries were the tiny spines and teeth of priapulid worms -- small hook shaped structures that allowed these worms to efficiently burrow through the sediments and capture prey. Other finds included the tough outer cuticles and defensive spines of various arthropods, and perhaps most surprisingly, microscopic fragments of the oldest known pterobranch hemichordates -- an obscure group of tube-dwelling filter feeders that are distant relatives of the vertebrates. This group became very diverse after the Cambrian Period and are among some of the most commonly found fossils in rocks from younger deposits, but were entirely unknown from the early Cambrian. This new source of fossils will also help palaeontologists to better understand the famously difficult to interpret fossils at the nearby Sirius Passet site, where the flattened animal fossils are usually complete, but missing crucial microscopic details.

Read more at Science Daily

Star mergers: A new test of gravity, dark energy theories

Artist's illustration of two merging neutron stars. The rippling space-time grid represents gravitational waves that travel out from the collision, while the narrow beams show the bursts of gamma rays that are shot out just seconds after the gravitational waves. Swirling clouds of material ejected from the merging stars are also depicted. The clouds glow with visible and other wavelengths of light.

When scientists recorded a rippling in space-time, followed within two seconds by an associated burst of light observed by dozens of telescopes around the globe, they had witnessed, for the first time, the explosive collision and merger of two neutron stars.

The intense cosmological event observed on Aug. 17 also had other reverberations here on Earth: It ruled out a class of dark energy theories that modify gravity, and challenged a large class of theories.

Dark energy, which is driving the accelerating expansion of the universe, is one of the biggest mysteries in physics. It makes up about 68 percent of the total mass and energy of the universe and functions as a sort of antigravity, but we don't yet have a good explanation for it. Simply put, dark energy acts to push matter away from each other, while gravity acts to pull matter together.

The neutron star merger created gravitational waves -- a squiggly distortion in the fabric of space and time, like a tossed stone sending ripples across a pond -- that traveled about 130 million light-years through space, and arrived at Earth at almost the same instant as the high-energy light that jetted out from this merger.

The gravity waves signature was detected by a network of Earth-based detectors called LIGO and Virgo, and the first intense burst of light was observed by the Fermi Gamma-ray Space Telescope.

That nearly simultaneous arrival time is a very important test for theories about dark energy and gravity.

"Our results make significant progress to elucidate the nature of dark energy," said Miguel Zumalacárregui, a theoretical physicist who is part of the Berkeley Center for Cosmological Physics at the Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and UC Berkeley.

"The simplest theories have survived," he said. "It's really about the timing."

He and Jose María Ezquiaga, who was a visiting Ph.D. researcher in the Berkeley Center for Cosmological Physics, participated in this study, which was published Dec. 18 in the journal Physical Review Letters.

A 100-year-old "cosmological constant" theory introduced by Albert Einstein in relation to his work on general relativity and some other theories derived from this model remain as viable contenders because they propose that dark energy is a constant in both space and time: Gravitational waves and light waves are affected in the same way by dark energy, and thus travel at the same rate through space.

"The favorite explanation is this cosmological constant," he said. "That's as simple as it's going to get."

There are some complicated and exotic theories that also hold up to the test presented by the star-merger measurements. Massive gravity, for example -- a theory of gravity that assigns a mass to a hypothetical elementary particle called a graviton -- still holds a sliver of possibility if the graviton has a very slight mass.

Some other theories, though, which held that the arrival of gravitational waves would be separated in time from the arriving light signature of the star merger by far longer periods -- stretching up to millions of years -- don't explain what was seen, and must be modified or scrapped.

The study notes that a class of theories known as scalar-tensor theories is particularly challenged by the neutron-star merger observations, including Einstein-Aether, MOND-like (relating to modified Newtonian dynamics), Galileon, and Horndeski theories, to name a few.

With tweaks, some of the challenged models can survive the latest test by the star merger, Zumalacárregui said, though they "lose some of their simplicity" in the process.

Zumalacárregui joined the cosmological center last year and is a Marie Sk?odowska-Curie global research fellow who specializes in studies of gravity and dark energy.

He began studying whether gravitational waves could provide a useful test of dark energy following the February 2016 announcement that the two sets of gravitational-wave detectors called LIGO (the Laser Interferometer Gravitational-Wave Observatory) captured the first confirmed measurement of gravitational waves. Scientists believe those waves were created in the merger of two black holes to create a larger black hole.

But those types of events do not produce an associated burst of light. "You need both -- not just gravitational waves to help test theories of gravity and dark energy," Zumalacárregui said.

Another study, which he published with Ezquiaga and others in April 2017, explored the theoretical conditions under which gravity waves could travel at a different velocity than light.

Another implication for this field of research is that, by collecting gravitational waves from these and possibly other cosmological events, it may be possible to use their characteristic signatures as "standard sirens" for measuring the universe's expansion rate.

This is analogous to how researchers use the similar light signatures for objects -- including a type of exploding stars known as Type Ia supernovae and pulsating stars known as cepheids -- as "standard candles" to gauge their distance.

Cosmologists use a combination of such measurements to build a so-called distance ladder for gauging how far away a given object is from Earth, but there are some unresolved discrepancies that are likely due to the presence of space dust and imperfections in calculations.

Gathering more data from events that generate both gravitational waves and light could also help resolve different measurements of the Hubble constant -- a popular gauge of the universe's expansion rate.

The Hubble rate calibrated with supernovae distance measurements differs from the Hubble rate obtained from other cosmological observations, Zumalacárregui noted, so finding more standard sirens like neutron-star mergers could possibly improve the distance measurements.

The August neutron star merger event presented an unexpected but very welcome opportunity, he said.

"Gravitational waves are a very independent confirmation or refutation of the distance ladder measurements," he said. "I'm really excited for the coming years. At least some of these nonstandard dark energy models could explain this Hubble rate discrepancy.

"Maybe we have underestimated some events, or something is unaccounted for that we'll need to revise the standard cosmology of the universe," he added. "If this standard holds, we will need radically new theoretical ideas that are difficult to verify experimentally, like multiple universes -- the multiverse. However, if this standard fails, we will have more experimental avenues to test those ideas."

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