Category: Science News

{Deaths from ovarian cancer fell worldwide between 2002 and 2012 and are predicted to continue to decline in the USA, European Union (EU) and, though to a smaller degree, in Japan by 2020, according to new research published in the leading cancer journal Annals of Oncology today.}

The main reason is the use of oral contraceptives and the long-term protection against ovarian cancer that they provide, say the researchers, who are led by Professor Carlo La Vecchia (MD), from the Faculty of Medicine, University of Milan (Italy). They say the decline in hormone replacement therapy (HRT) to manage menopausal symptoms and better diagnosis and treatment may also play a role.

Using data on deaths from ovarian cancer from 1970 to the most recent available year from the World Health Organization, the researchers found that in the 28 countries of the EU (minus Cyprus due to the unavailability of data) death rates decreased by 10% between 2002 and 2012, from an age standardised death rate per 100,000 women of 5.76 to 5.19.*

In the USA the decline was even greater, with a 16% drop in death rates from 5.76 per 100,000 in 2002 to 4.85 in 2012. In Canada ovarian cancer death rates decreased over the same period by nearly 8% from 5.42 to 4.95. In Japan, which has had a lower rate of ovarian cancer deaths than many other countries, the death rate fell by 2% from 3.3 to 3.28 per 100,000. Large decreases occurred in Australian and New Zealand between 2002 and 2011 (the most recent year for which data were available); in Australia the death rate declined by nearly 12% from 4.84 to 4.27, and in New Zealand they dropped by 12% from 5.61 to 4.93 per 100,000 women.

However, the pattern of decreases was inconsistent in some areas of the world, for instance in Latin American countries and in Europe. Among European countries, the percentage decrease ranged from 0.6% in Hungary to over 28% in Estonia, while Bulgaria was the only European country to show an apparent increase. In the UK, there was a 22% decrease in death rates, which fell from 7.5 to 5.9 per 100,000 women. Other EU countries that had large decreases included Austria (18%), Denmark (24%) and Sweden (24%).

The Latin American countries tended to have lower rates of deaths from ovarian cancer. Argentina, Chile and Uruguay showed decreases between 2002 and 2012, but Brazil, Colombia, Cuba, Mexico and Venezuela all showed increases in death rates.

Prof La Vecchia said: “The large variations in death rates between European countries have reduced since the 1990s when there was a threefold variation across Europe from 3.6 per 100,000 in Portugal to 9.3 in Denmark. This is likely to be due to more uniform use of oral contraceptives across the continent, as well as reproductive factors, such as how many children a woman has. However, there are still noticeable differences between countries such as Britain, Sweden and Denmark, where more women started to take oral contraceptives earlier — from the 1960s onwards — and countries in Eastern Europe, but also in some other Western and Southern European countries such as Spain, Italy and Greece, where oral contraceptive use started much later and was less widespread.

“This mixed pattern in Europe also helps to explain the difference in the size of the decrease in ovarian cancer deaths between the EU and the USA, as many American women also started to use oral contraceptives earlier.

“Japan, where deaths from ovarian cancer have traditionally been low, now has higher rates in the young than the USA or the EU — again, reflecting infrequent oral contraceptive use.”

Another researcher, Dr Eva Negri, Head of Epidemiologic Methods at the IRCCS Istituto di Ricerche Farmacologiche Mario Negri in Milan, added: “Women in countries such as Germany, the UK and the USA were also more likely to use hormone replacement therapy to manage menopausal symptoms than in some other countries. The use of HRT declined after the report from the Women’s Health Initiative in 2002 highlighted the increased risk of cardiovascular disease, as well as breast and ovarian cancer, and so this may also help to explain the fall in death rates among middle-aged and older women in these countries.”

The researchers predicted the age-standardised ovarian cancer death rates for France, Germany, Italy, Poland, Spain and the UK, and for the whole of the USA, the EU and Japan up to 2020. They expect there will be a 15% decline in the USA and a 10% decline in the EU and Japan. Of the six European countries, only Spain showed a slight increase from 3.7 per 100,000 women to 3.9. “This is possibly due to the fact that women who are middle-aged or elderly now were less likely to use oral contraceptives when they were young,” concluded Prof La Vecchia.

Professor Paolo Boffetta (MD), the Annals of Oncology associate editor for epidemiology and Associate Director for Population Sciences at the Tisch Cancer Institute of the Icahn School of Medicine at Mount Sinai in New York (USA), commented: “The findings of Professor La Vecchia and his colleagues are important as they show how past use of hormone treatments has an impact on the mortality from ovarian cancer at the population level. As our understanding of preventable causes of this major cancer progresses, early detection strategies are being developed and novel therapeutic options become available, we enhance our ability to reduce ovarian cancer mortality.”

{Two years ago, scientists revealed that, when plucked like a guitar string, spider silk transmits vibrations across a wide range of frequencies, carrying information about prey, mates and even the structural integrity of a web. Now, a new collaboration has confirmed that spider webs are superbly tuned instruments for vibration transmission — and that the type of information being sent can be controlled by adjusting factors such as web tension and stiffness.}

Two years ago, a research team led by the University of Oxford revealed that, when plucked like a guitar string, spider silk transmits vibrations across a wide range of frequencies, carrying information about prey, mates and even the structural integrity of a web.

Now, a new collaboration between Oxford and Universidad Carlos III de Madrid has confirmed that spider webs are superbly tuned instruments for vibration transmission — and that the type of information being sent can be controlled by adjusting factors such as web tension and stiffness.

Researchers from the Oxford Silk Group, along with collaborators in Oxford’s Department of Engineering Science and Universidad Carlos III de Madrid’s Department of Continuum Mechanics and Structural Analysis, have studied the links between web vibration and web silk properties.

Their report in the Journal of the Royal Society Interface concludes that spider web vibration is affected by changes in web tension, silk stiffness and web architecture, all of which the spider is able to control.

Web-dwelling spiders have poor vision and rely almost exclusively on web vibrations for their ‘view’ of the world. The musical patterns coming from their tuned webs provide them with crucial information on the type of prey caught in the web and of predators approaching, as well as the quality of prospective mates. Spiders carefully engineer their webs out of a range of silks to control web architecture, tension and stiffness, analogous to constructing and tuning a musical instrument.

In order to study how vibrations propagate through a web, a combination of cutting-edge techniques was employed by the interdisciplinary and multinational team. High-powered lasers were able to experimentally measure the ultra-small vibrations, which allowed the team to generate and test computer models using mathematical finite element analysis. The combination of these techniques probes the links between the propagation of vibrations and silk material properties.

These new observations propose that the spider can use behaviour and silk properties to control the function of its web instrument. These control mechanisms could alter vibration filtering, as well as orientation to and discrimination of vibration sources in the web.

Dr Beth Mortimer, lead author of the report, which made use of the garden cross spider Araneus diadematus, said: ‘Spider orb webs are multifunctional structures, where both the transmission of vibrations and the capture of prey are important.’

Professor Fritz Vollrath, Head of the Oxford Silk Group, added: ‘It is down to the interaction of the web materials, a range of bespoke web silks, and the spider with its highly tuned behaviour and armoury of sensors that allows this virtually blind animal to operate in a gossamer world of its own making, without vision and only relying on feeling. Perhaps the web spider can teach us something new about virtual vision.’

{Skinny lines of ants snake through the rainforest carrying leaves and flowers above their heads — fertilizer for industrial-scale, underground fungus farms. Soon after the dinosaur extinctions 60 million years ago, the ancestors of leaf-cutter ants swapped a hunter-gatherer lifestyle for a bucolic existence on small-scale subsistence farms. A new study at the Smithsonian Tropical Research Institute (STRI) in Panama revealed that living relatives of these earliest fungus-farming ants still have not domesticated their crop, a challenge also faced by early human farmers.
}

Modern leaf-cutter ants can not live without their fungus and the fungus can not live without the ants — in fact, young queens carry a bit from the nests where they were born when they fly out to establish a new nest. The fungus, in turn, does not waste energy-producing spores to reproduce itself.

“For this sort of tight mutual relationship to develop, the interests of the ants and the fungi have to be completely aligned, like when business partners agree on all the terms in a contract,” said Bill Wcislo, deputy director at the STRI and co-author of the new publication in the Proceedings of the National Academy of Sciences. “We found that the selfish interests of more primitive ancestors of leaf-cutting ants are still not in line with the selfish interests of their fungal partner, so complete domestication hasn’t really happened yet.”

Just as human farmers harvest their vegetables before they go to seed, ants want their fungus to minimize the amount of energy it puts into creating inedible mushrooms full of spores. It is best for the ants if the fungus grows more of the fungal hyphae that fill up the chambers in their underground gardens and serve as food for the ants and their larvae.

In a study of Mycocepurus smithii, an ancestor of the leaf-cutters that has not yet domesticated its fungal crop, at the Smithsonian research center in Gamboa, Panama, Jonathan Shik, a Marie Curie Post-Doctoral Fellow in Jacobus Boomsma’s lab at the University of Copenhagen, and collaborators discovered that the ants adjust the protein and carbohydrate concentration of the mulch they provide to minimize the amount of mushrooms that their non-domesticated fungal cultivars produce. When they provide mulches rich in carbohydrates, the fungus can produce both hyphae and mushrooms, but carefully provisioned doses of protein can prevent the fungi from making mushrooms. However, this strategy of keeping their fungus in line requires that the total output of their fungus gardens remain low.

“The parallels between ant fungus farming and human agriculture are uncanny,” said Shik. “Human agriculture evolved in the past 10,000 years.”

“It took 30 million years of natural selection until the higher attine ants fully domesticated one of their fungal symbiont lineages. We think that finally resolved this farmer-crop conflict and removed constraints on increased productivity, producing the modern leaf-cutter ants 15 million years ago,” said Boomsma. “In contrast, it took human farmers relatively little time to domesticate fruit crops and to select for seedless grapes, bananas and oranges.”

{For (probably) the first time ever, plants modified with the “genetic scissors” CRISPR-Cas9 has been cultivated, harvested and cooked. Stefan Jansson, professor in Plant Cell and Molecular Biology at Umeå University, served pasta with “CRISPRy” vegetable fry to a radio reporter. Although the meal only fed two people, it was still the first step towards a future where science can better provide farmers and consumers across the world with healthy, beautiful and hardy plants.}

CRISPR (Clustered regularly interspaced short palindromic repeats)-Cas9 is a complicated name for an easy, but targeted, way of changing the genes of an organism. The decisive discovery was published in 2012 by researchers at Umeå University, and the “Swiss army knife of genetic engineering” has been predicted to change the world. With CRISPR-Cas9, researchers can either replace one of the billions of “letters” present in an organism’s genome (i.e. the entire gene pool consisting of DNA) or remove short segments, similar to when you edit a written text in a word processor. The technology is called “gene editing” or “genome editing.”

The first clinical applications are underway; maybe we can soon cure hereditary disease using this technology. However, the situation differs somewhat in the agricultural field. There, the issue is not IF researchers can create plants leading to a more sustainable land management, but rather if these will be allowed in farming. Will plants whose genome has been edited using CRISPR-Cas9 fall under GMO legislation or not? If they do, it makes them illegal to plant in great parts of the world. If not, they will — just like other plants — be allowed to be grown at the farmers own discretion.

The EU has avoided answering the question, but in November 2015 the Swedish Board of Agriculture interpreted the law as if only a segment of DNA has been removed and no “foreign DNA” has been inserted, it is not to be regarded as a genetically modified organism — a GMO. That also means that the plant can be cultivated without prior permission. In spring 2016, American authorities stated that they agreed. The organism in question there was a mushroom who had lost the part of its DNA that made it go brown. This opens up for using the technology to develop plants of the future.

This summer has been the first time that plants that have been gene-edited using CRISPR-Cas9 — in a way that does not classify the plant as GMO — have been allowed to be cultivated outside of the lab. This is definitely the first time in Europe, and even if it been done before in other parts of the world, it has been kept secret. This time, it was a cabbage plant and the Radio Sweden gardening show “Odla med P1” took part in the harvest leading to the probably first-ever meal of CRISPR-Cas9 genome-edited plants. The first CRISPR meal to have been enjoyed was “Tagliatelle with CRISPRy fried vegetables.”

“The CRISPR-plants in question grew in a pallet collar in a garden outside of Umeå in the north of Sweden and were neither particularly different nor nicer looking than anything else,” says plant scientist Stefan Jansson. But they represent both a new phase of agriculture where scientific advances will be implemented in new plant species and that to a small or large extent will be made available to farmers across the world. In other words: a meal for the future.

{Smoking the equivalent of a single ‘spliff’ of cannabis makes people less willing to work for money while ‘high’.}

Smoking the equivalent of a single ‘spliff’ of cannabis makes people less willing to work for money while ‘high,’ finds a new study. The research is the first to reliably demonstrate the short-term effects of cannabis on motivation in humans. The researchers also tested motivation in people who were addicted to cannabis but not high during the test, and found that their motivation levels were no different to volunteers in the control group.

“Although cannabis is commonly thought to reduce motivation, this is the first time it has been reliably tested and quantified using an appropriate sample size and methodology,” says lead author Dr Will Lawn (UCL Clinical Psychopharmacology). “It has also been proposed that long-term cannabis users might also have problems with motivation even when they are not high. However, we compared people dependent on cannabis to similar controls, when neither group was intoxicated, and did not find a difference in motivation. This tentatively suggests that long-term cannabis use may not result in residual motivation problems when people stop using it. However, longitudinal research is needed to provide more conclusive evidence.”

57 volunteers were involved in the research, which consisted of two separate studies. The first involved 17 adult volunteers who all used cannabis occasionally. Through a balloon, they inhaled cannabis vapour on one occasion and cannabis-placebo vapour on separate occasion. Straight after, they completed a task designed to measure their motivation for earning money. This was a real-life task as the volunteers were given money they had earned at the end of the experiment.

In each trial of the task, volunteers could choose whether to complete low- or high-effort tasks to win varying sums of money. The low-effort option involved pressing the spacebar key with the little finger of their non-dominant hand 30 times in 7 seconds to win 50p. The high-effort option involved 100 space bar presses in 21 seconds, for rewards varying from 80p to £2.

“Repeatedly pressing keys with a single finger isn’t difficult but it takes a reasonable amount of effort, making it a useful test of motivation,” explains senior author Professor Val Curran (UCL Clinical Psychopharmacology). “We found that people on cannabis were significantly less likely to choose the high-effort option. On average, volunteers on placebo chose the high-effort option 50% of the time for a £2 reward, whereas volunteers on cannabis only chose the high-effort option 42% of the time.”

In the second study, 20 people addicted to cannabis were matched with 20 control participants who reported the same levels of non-cannabis drug use. Participants were not allowed to consume alcohol or drugs, other than tobacco or coffee, for 12 hours before the study. They were then asked to perform the same motivation task as participants in the first study. The results showed that cannabis-dependent volunteers were no less motivated than the control group. However, much more research is needed to fully understand the relationship between long-term cannabis use and possible amotivational deficits.

{Scientists from the Higher School of Economics (HSE) together with colleagues from the University of Helsinki have discovered that learning foreign languages enhances the our brain’s elasticity and its ability to code information. The more foreign languages we learn, the more effectively our brain reacts and processes the data accumulated in the course of learning. An article of Yury Shtyrov, Leading Research Fellow of the HSE Centre for Cognition & Decision Making, Lilli Kimppa and Teija Kujala (University of Helsinki) summarizing the new findings has been recently published in Scientific Reports.}

According to the study, the neurophysiological mechanics of language and speech acquisition are underexplored when compared to the brain’s other functions. The reason for such scarce attention is the inability to study verbal function on test animals.

Researchers carried out experiments where the brain’s electrical activity was measured with EEG (electroencephalography). Twenty-two students in total (10 male and 12 female) participated in the investigation, with the average age being 24. The subjects had electrodes placed on their heads and then listened to recordings of different words in their native language, as well in foreign languages, both known and completely unknown by the subjects. When the known or unknown words popped up, changes in the brain’s activity were tracked. Researchers especially focused on the speed at which the brain readjusted its activity to treat unknown words. Afterwards, the accrued neurophysiological data was compared to the subjects’ linguistic background: how many languages they knew, at which age they started to learn it, and so on. Apparently, the ability of the brain to quickly process information depends on one’s “linguistic anamneses.”

The experiment has shown that the brain’s electrical activity of those participants who had already known some foreign languages, was higher. The author of the study, Yuriy Shtyrov commented that the more languages someone mastered, the faster the neuron network coding the information on the new words was formed. Consequently, this new data stimulates the brain’s physiology: loading the mind with more knowledge boosts its elasticity.

Scientists believe that understanding how the brain functions in acquiring language is of crucial importance in diagnosing speech impediments after accidents, strokes, and other related conditions, and finding ways to treat them. Moreover, when we achieve better insight into the principles of creating and strengthening neuron networks, we will be able to harness these mechanisms, speed them up and improve the learning process.

{Researchers have engineered a low-cost plastic material that could become the basis for clothing that cools the wearer, reducing the need for energy-consuming air conditioning.}

Stanford engineers have developed a low-cost, plastic-based textile that, if woven into clothing, could cool your body far more efficiently than is possible with the natural or synthetic fabrics in clothes we wear today.

Describing their work in Science, the researchers suggest that this new family of fabrics could become the basis for garments that keep people cool in hot climates without air conditioning.

“If you can cool the person rather than the building where they work or live, that will save energy,” said Yi Cui, an associate professor of materials science and engineering and of photon science at Stanford.

This new material works by allowing the body to discharge heat in two ways that would make the wearer feel nearly 4 degrees Fahrenheit cooler than if they wore cotton clothing.

The material cools by letting perspiration evaporate through the material, something ordinary fabrics already do. But the Stanford material provides a second, revolutionary cooling mechanism: allowing heat that the body emits as infrared radiation to pass through the plastic textile.

All objects, including our bodies, throw off heat in the form of infrared radiation, an invisible and benign wavelength of light. Blankets warm us by trapping infrared heat emissions close to the body. This thermal radiation escaping from our bodies is what makes us visible in the dark through night-vision goggles.

“Forty to 60 percent of our body heat is dissipated as infrared radiation when we are sitting in an office,” said Shanhui Fan, a professor of electrical engineering who specializes in photonics, which is the study of visible and invisible light. “But until now there has been little or no research on designing the thermal radiation characteristics of textiles.”

{{Super-powered kitchen wrap}}

To develop their cooling textile, the Stanford researchers blended nanotechnology, photonics and chemistry to give polyethylene — the clear, clingy plastic we use as kitchen wrap — a number of characteristics desirable in clothing material: It allows thermal radiation, air and water vapor to pass right through, and it is opaque to visible light.

The easiest attribute was allowing infrared radiation to pass through the material, because this is a characteristic of ordinary polyethylene food wrap. Of course, kitchen plastic is impervious to water and is see-through as well, rendering it useless as clothing.

The Stanford researchers tackled these deficiencies one at a time.

First, they found a variant of polyethylene commonly used in battery making that has a specific nanostructure that is opaque to visible light yet is transparent to infrared radiation, which could let body heat escape. This provided a base material that was opaque to visible light for the sake of modesty but thermally transparent for purposes of energy efficiency.

They then modified the industrial polyethylene by treating it with benign chemicals to enable water vapor molecules to evaporate through nanopores in the plastic, said postdoctoral scholar and team member Po-Chun Hsu, allowing the plastic to breathe like a natural fiber.

{{Making clothes
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That success gave the researchers a single-sheet material that met their three basic criteria for a cooling fabric. To make this thin material more fabric-like, they created a three-ply version: two sheets of treated polyethylene separated by a cotton mesh for strength and thickness.

To test the cooling potential of their three-ply construct versus a cotton fabric of comparable thickness, they placed a small swatch of each material on a surface that was as warm as bare skin and measured how much heat each material trapped.

“Wearing anything traps some heat and makes the skin warmer,” Fan said. “If dissipating thermal radiation were our only concern, then it would be best to wear nothing.”

The comparison showed that the cotton fabric made the skin surface 3.6 F warmer than their cooling textile. The researchers said this difference means that a person dressed in their new material might feel less inclined to turn on a fan or air conditioner.

The researchers are continuing their work on several fronts, including adding more colors, textures and cloth-like characteristics to their material. Adapting a material already mass produced for the battery industry could make it easier to create products.

“If you want to make a textile, you have to be able to make huge volumes inexpensively,” Cui said.

Fan believes that this research opens up new avenues of inquiry to cool or heat things, passively, without the use of outside energy, by tuning materials to dissipate or trap infrared radiation.

“In hindsight, some of what we’ve done looks very simple, but it’s because few have really been looking at engineering the radiation characteristics of textiles,” he said.

{Childhood bullying inflicts the same long-term psychological trauma on girls as severe physical or sexual abuse, suggests a new survey of college students led by bullying researcher.}

Childhood bullying inflicts the same long-term psychological trauma on girls as severe physical or sexual abuse, suggests a new survey of college students.

The study, which involved 480 college freshmen through seniors, indicated that the detrimental effects of bullying may linger for years, negatively affecting victims’ mental health well into young adulthood. While most of the scholarship on bullying has focused on kindergarten through 12th-grade students, the struggles revealed by college students who participated in the research suggest a need to develop assessments and interventions for this population, according to the researchers.

Participants in the study were surveyed about their exposure to a variety of traumatic experiences — including bullying, cyberbullying and crimes such as robbery, sexual assault, and domestic and community violence — from birth through age 17. Students also reported on their psychological functioning and symptoms of depression, anxiety and post-traumatic stress disorder.

The students who experienced bullying as children reported significantly greater levels of mental health problems than their peers, according to the study, published online by the journal Social Psychology of Education.

Educational psychologist Dorothy Espelage conducted the study while on the faculty of the University of Illinois, where she held appointments as the Hardie Scholar and the Edward William and Jane Marr Gutgsell Endowed Professor of Education.

Currently a professor of psychology at the University of Florida, Espelage is a nationally recognized expert on bullying, sexual harassment, homophobic teasing, and dating and gang violence.

Experiencing bullying was the strongest predictor of PTSD symptoms among the college students who participated in the survey, surpassing other types of trauma such as exposure to community violence or being abused or neglected by adults, Espelage and her co-authors found.

Females in particular struggled with the emotional damage inflicted by bullying, reporting significantly greater levels of depression, anxiety and PTSD than their male peers, according to the study.

“Bullying victimization significantly predicted students’ current levels of depression and anxiety — over and above other childhood victimization experiences,” Espelage said. “The prevalence of psychological distress in children who have been bullied is well-documented, and this research suggests that college students’ psychological distress may be connected in part to their perceptions of past childhood bullying victimization experiences.”

Students who experienced one interpersonal trauma were at the greatest risk of being victimized in other ways and of developing PTSD, the data indicated.

The researchers suggested that practitioners in college mental health centers need to be aware that students who request psychological help are likely to have experienced multiple forms of trauma that need to be assessed.

Practitioners should routinely collect information about the various types of trauma students may have experienced to identify those people at greatest risk of experiencing PTSD, the researchers advised.

A critical first step in restoring troubled college students’ social and behavioral functioning would be to provide clinicians at campus counseling centers with continued training on the current research on childhood bullying and its long-term effects, Espelage and her co-authors wrote.

The researchers also recommended that universities broaden the curricula of their sexual assault programs to encompass various other traumatic experiences, such as child abuse and domestic violence.

Connecting students with interventions that help them develop protective social support networks may be the best way to help them cope with the emotional aftermath of bullying and other traumatic experiences, the researchers suggested.

“Practitioners, in collaboration with school officials, need to make all efforts to develop and implement programs that increase traumatized students’ sense of empowerment and control as they navigate through college,” Espelage said. “This would be possible in a campus climate that fosters supportive ties among students, and between students and the campus community.”

U. of I. alumnus Jun Sung Hong, currently a professor of social work at Wayne State University, and Sarah Mebane of the Marine Corps Community Services co-wrote the study.

{Remarkable find by team of Australian researchers points to earliest existence of diverse life on Earth.
}
A team of Australian researchers has uncovered the world’s oldest fossils in a remote area of Greenland, capturing the earliest history of the planet and demonstrating that life on Earth emerged rapidly in the planet’s early years. The team discovered 3.7-billion-year-old stromatolite fossils in the world’s oldest sedimentary rocks, in the Isua Greenstone Belt along the edge of Greenland’s icecap.

In an extraordinary find, a team of Australian researchers have uncovered the world’s oldest fossils in a remote area of Greenland, capturing the earliest history of the planet and demonstrating that life on Earth emerged rapidly in the planet’s early years.

Led by the University of Wollongong’s (UOW) Professor Allen Nutman, the team discovered 3.7-billion-year-old stromatolite fossils in the world’s oldest sedimentary rocks, in the Isua Greenstone Belt along the edge of Greenland’s icecap.

The findings are outlined in a study published in Nature, with co-authors Associate Professor Vickie Bennett from The Australian National University (ANU), the University of New South Wales’ (UNSW) Professor Martin Van Kranendonk, and Professor Allan Chivas, from UOW.

The discovery of the Isua stromatolite fossils provides a greater understanding of early diversity of life on Earth and researchers said could have implications for our understanding of life on Mars. Professor Nutman, from UOW’s School of Earth and Environmental Sciences, said the Isua stromatolite fossils predated the world’s previous oldest stromatolite fossils — which were found in Western Australia — by 220 million years.

The discovery pushes back the fossil record to near the start of Earth’s geological record and points to evidence of life on Earth very early in its history. The Isua stromatolites, which were exposed by the recent melting of a perennial snow patch, were laid down in shallow sea, providing the first evidence of an environment in which early life thrived.

For much of Earth’s history, life was just single cells, and stromatolite fossils are mounds of carbonate constructed by these communities of microbes.

“The significance of stromatolites is that not only do they provide obvious evidence of ancient life that is visible with the naked eye, but that they are complex ecosystems,” Professor Nutman said.

“This indicates that as long as 3.7 billion years ago microbial life was already diverse. This diversity shows that life emerged within the first few hundred millions years of Earth’s existence, which is in keeping with biologists’ calculations showing the great antiquity of life’s genetic code.”

Co-lead investigator Associate Professor Vickie Bennett, from ANU, said this study provided a new perspective into the history of Earth.

“This discovery turns the study of planetary habitability on its head,” Associate Professor Bennett said.

“Rather than speculating about potential early environments, for the first time we have rocks that we know record the conditions and environments that sustained early life. Our research will provide new insights into chemical cycles and rock-water-microbe interactions on a young planet.”

Professor Martin Van Kranendonk, Director of the Australian Centre for Astrobiology at UNSW, of which Professor Nutman is also an Associate Member, said it was a groundbreaking find that could point to similar life structures on Mars, which 3.7 billion years ago was a damp environment.

“The structures and geochemistry from newly exposed outcrops in Greenland display all of the features used in younger rocks to argue for a biological origin,” Professor Van Kranendonk said.

“This discovery represents a new benchmark for the oldest preserved evidence of life on Earth. It points to a rapid emergence of life on Earth and supports the search for life in similarly ancient rocks on Mars.”

The investigation, conducted by the Australian science team in collaboration with a UK partner, was funded by a grant from the Australian Research Council.

{Violent thunderstorms can often cause torrential rain, which pose a threat for both humans and the infrastructure. Until now such extreme weather phenomena have been very poorly understood. However, using advanced simulations for cloud systems, researchers also from the Niels Bohr Institute have determined how complex cloud systems build up in the atmosphere, which then interact with each other and strengthen the further build up of heavy rain and severe thunderstorms.The results are published in the scientific journal, Nature Geoscience.}

Using high-resolution cloud models, researchers from the Max Planck Institute for Meteorology in Hamburg, the Swedish Meteorological and Hydrological Institute in Norrköping and the Niels Bohr Institute at the University of Copenhagen analysed how heavy rainfall is affected by rising temperatures. The simulations were performed over an area that typically constitutes a single field area in climate models, that is, an area of 200 km x 200 km. In the high-resolution cloud model the area is divided into smaller areas of 200 meters, resulting in a 1000 times greater resolution. The high resolution made it possible for the researchers to uncover the processes taking place in the atmosphere, which are only included in global climate models to a very approximate degree.

“To detect the physical process that form, for example, storm clouds, we use simulations that are capable of revealing local thermal and moisture variations, which give rise to so-called ‘convective’ clouds. Convection is the process that forms, for example, thunderstorm clouds. Due to the heating of the surface in connection with sufficient humidity, a warm updraft is released in the atmosphere. Traditional climate models do not see these processes to an adequate degree. It is interesting how systematically convective clouds occur. Where two clouds collide, new and stronger clouds often appear,” explains Jan O. Haerter, researcher at the Niels Bohr Institute at the University of Copenhagen.

Clouds are affected from the outside and inside

The simulations in the atmosphere build up a state of organisation that the researchers describe as a kind of ‘memory’.

“What we see here is a so-called complex system. The way the atmosphere behaves is not only influenced by large scales, but is also due to what we call self-organisation. Convective clouds come and go within a certain period. Over the course of the day, these periods increase and so does the intensity of rain,” explains Jan O. Haerter.

Their results show that heavy rain is produced when multiple clouds collide and thus interact with each other. Without these collisions between clouds, the rain remains light.

Isolated rain showers show no change in intensity with increasing temperatures, but rising temperatures lead to more frequent collisions of convective cloud systems. The researchers compare this dynamic to that of small streams merging to form larger rivers — in an analogous way collisions between cloud systems can result in heavier rain.

The new results therefore contradict the traditional global climate models where convective clouds are seen as being independent of each other.

{{Temperature sensitive rain clouds}}

In previous studies, the researchers discovered that heavy, thunderous rain showers that are often seen during summer in temperate latitudes were much more sensitive to temperature than expected.

The researchers found that when the temperature rose, these high clouds behaved very differently from the clouds that were spread over large areas, but they could not determine the main reason for the increased rainfall from the measurements alone.

“With the new model calculations, we are getting a better understanding of the intense thunderstorms that can lead to the severe flooding that often occurs in temperate latitudes,” explains Jan O. Haerter.