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Looking closely at the small, worm-like nematode Eubostrichus dianeae under a microscope, one would observe what appears to be a carpet of long fur tendrils covering the exterior of the worm. Look even more closely and one would realize that the fur is in fact a mass of ectosymbiont bacteria, Gammaproteobacteria, that lives by attaching one end to the surface of the nematode’s cuticle, its outer surface. The longest of these bacteria is a stunning 140 microns long, at the threshold of perception according to resolution capabilities of our eye. In comparison, the common Escherichia coli is about 2 microns long. The nematode Eubostrichus fertilis is similarly covered by a carpet of shorter bacteria (image above), each of which is attached on both ends, and aligned along the long axis of the body.
Scientists at the University of Vienna have found that the exceptionally long bacteria coating the two nematodes exhibit exquisite control of division despite the bacteria having a one order-of-magnitude variation in size. On Eubostrichus dianeae, the bacteria size range from 16 to 140 microns (0.016 to 0.140 mm). In Eubostrichus fertilis, the bacteria range from 3 to 45 microns (0.003 to 0.045 mm). Despite the variation, the bacteria exhibit exquisite control over the reproduction process. A hither-to yet unknown internal machinery generates a constricting ring in the exact center, pinching off two progeny bacteria in a process of symmetric division.
DNA sequencing revealed that the bacteria on E dianeae and E fertilis are pure respectively, each belonging to a sulphur-oxidizing family. The exact species identities of the bacteria are not known. To establish the genetic uniformity, the researchers sequenced the well-conserved 16s ribosome, a universal protein-building machinery found in all bacteria and all life. This allowed not only analysis of variation within the population of surface-coating bacteria, but also a comparison to sequence information in existing databases. The resulting ribosomal sequences matched closely bacteria that had been characterized on other marine nematodes.
Wild chimps learning to use tools from each other may hint at humanity's past. We finally caught wild chimpanzees teaching each other new ways to drink water.
Under a tree in Uganda’s Budongo forest in 2013, Catherine Hobaiter first mentioned the strange chimp behaviors she'd seen two years before. Hobaiter, a chimpanzee researcher at the University of St. Andrews in the UK, told fellow primatologist Thibaud Gruber that she had witnessed a group of chimps using a mix of moss and leaves to soak up drinking water from a watering hole in the forest. In 20 years of research, no one had observed this behavior in this community of chimps, and yet Hobaiter had managed to capture the behavior on video — numerous times.
"When she told me that she had all the videos on her laptop and, most importantly, that we could probably extract from these videos all the information necessary to document the spread of the behavior within the community," Gruber explains, "I knew we were in business!"
Chimpanzees are widely considered the most "cultural" of all non-human animals, Gruber says. Their ability to use tools is well-known, and their capacity to transmit those behaviors socially has garnered a lot of attention in recent years. Until now, though, observations of chimps learning to use tools from each other had only taken place in captivity — a setting that, necessarily, doesn't resemble the wild. Captivity had limited the ecological validity of the earlier findings, says Gruber, who works at the University of Neuchâtel in Switzerland.
In the recent study, published today in PLOS Biology, Gruber and his team investigated how two new variations of "leaf-sponge" use spreads across a population. These single-use tools are usually the result of a chimp folding leaves into its mouth and subsequently using it to drink, or even to collect honey in experimental conditions. But Hobaiter’s footage showed that some chimps reuse their sponges, whereas others make them by mixing moss into the leaves. "The chimpanzees just decided to display this novel behavior right in front of us," Gruber says, "and we only needed our camcorders to capture the scenes."
With the footage in hand, the researchers gathered data and ran statistical models. The goal was to see if these novel behaviors were socially transmitted from chimp to chimp. And, according to their results, moss-sponging was a product of social learning among the chimp population. Leaf-sponge reuse, on the other hand, wasn't. What's more, every time an individual sees another chimpanzee perform a behavior, that first chimp is 15 times more likely to develop the behavior, the research showed. "Most interestingly," Gruber says, "the spread of the behavior was very fast, with seven individuals acquiring the novel behavior in only six days." This shows that chimpanzees can adopt new tools very quickly.
Yeast. They already participate in producing some of the most popular pain-killing substances around: beer and wine. Now, scientists have engineered yeast that can also make one of the most powerful analgesics:morphine. Their work is in the journal Nature Chemical Biology. [Kate Thodey, Stephanie Galanie and Christina D. Smolke, A microbial biomanufacturing platform for natural and semisynthetic opioids]
Experimenting within quantum theory is an extremely complex process, where common intuitions are regularly inverted within shifting reality. Over the years several quantum features and methods of their study have been identified. Now scientists have investigated a new set of assumptions and proposed a novel experiment, to test the consequences of making quantum theory more intuitive.
"While quantum theory is the science behind almost all of our technology, its disconnect with our everyday intuitions is still worrisome and actively researched," says lead author Associate Professor Daniel Terno.
"How do you find your way in a reality which is shifting, where the opposites are allowed to coexist? Moreover, how do you conduct experiments in it? These are the questions that must be answered when dealing with the floating world of quantum mechanics."
Throughout the development of quantum theory, a set of reasonable ideas has led to strange paradoxes, such as the famous Schrodinger's cat, which is neither dead nor alive.
Using this wave-particle duality as their starting point, the research team investigated a new and more comprehensible set of assumptions:
In taking these assumptions and applying them to an experiment, where the measuring device is controlled by a Schrodinger's cat-like state, the research team reached some perplexing paradoxes.
"Only after the cat was found to be dead or alive were we able to tell if what we did was to look for a particle or for a wave," says Associate Professor Terno. "Then these three innocent-looking ideas result in predictions that would contradict an experiment. The universe simply does not work like that: you can see things to be real, or certain, but not both."
Then the researchers tweaked their initial assumptions, replacing the third assumption with the requirement that how you set your detectors does not affect the system you study before they interact. This tweak lead to another strange result: it is not only that our quantum world is not like that, but such a combination cannot be realized in any universe.
"We can just repeat after Alice: things get stranger and stranger"
A device called the Rochester Cloak uses an array of lenses to bend light, effectively rendering what is on the other side invisible to the eye. And you can try it for yourself.
One of the problems with the cloaking devices developed to date -- and it's a big one -- is that they really only work if both the viewer and whatever is being cloaked remain still. This, of course, is not entirely practical, but a difficult problem to solve.
For the first time, researchers have made a cloaking device that works multi-directionally in three dimensions -- using no specialized equipment, but four standard lenses.
"There've been many high tech approaches to cloaking and the basic idea behind these is to take light and have it pass around something as if it isn't there, often using high-tech or exotic materials," said professor of physics at Rochester University John Howell, who developed the Rochester Cloak with graduate student Joseph Choi.
"This is the first device that we know of that can do three-dimensional, continuously multidirectional cloaking, which works for transmitting rays in the visible spectrum," Choi added.
As well as at least partially solving the viewpoint problem, the Rochester cloak also leaves the background undisturbed, without any warping, as has appeared in other devices. This invisibility has a range of around 15 degrees; as you can see in the video below at around the two-minute mark when Choi places his hand in between the lenses, the dead centre of the field is not included.
Scientists at IBM Research have created by far the most advanced neuromorphic (brain-like) computer chip to date. The chip, called TrueNorth, consists of 1 million programmable neurons and 256 million programmable synapses across 4096 individual neurosynaptic cores. Built on Samsung’s 28nm process and with a monstrous transistor count of 5.4 billion, this is one of the largest and most advanced computer chips ever made. Perhaps most importantly, though, TrueNorth is incredibly efficient: The chip consumes just 72 milliwatts at max load, which equates to around 400 billion synaptic operations per second per watt — or about 176,000 times more efficient than a modern CPU running the same brain-like workload, or 769 times more efficient than other state-of-the-art neuromorphic approaches. Yes, IBM is now a big step closer to building a brain on a chip.
The animal brain (which includes the human brain, of course), as you may have heard before, is by far the most efficient computer in the known universe. As you can see in the graph below, the human brain has a “clock speed” (neuron firing speed) measured in tens of hertz, and a total power consumption of around 20 watts. A modern silicon chip, despite having features that are almost on the same tiny scale as biological neurons and synapses, can consume thousands or millions times more energy to perform the same task as a human brain. As we move towards more advanced areas of computing, such as artificial general intelligence and big data analysis — areas that IBM just happens to be deeply involved with — it would really help if we had a silicon chip that was capable of brain-like efficiency.
75 billion. That's the potential size of the Internet Things sector, which could become a multi-trillion dollar market by the end of the decade.
That's a very big number of devices that Morgan Stanley has extrapolated from a Cisco report that details how many devices will be connected to the Internet of Things by 2020. That's 9.4 devices for every one of the 8 billion people that's expected to be around in seven years.
To help put that into more perspective, back in Cisco also came out with the number of devices it thinks were connected to the Internet in 2012, a number Cisco's Rob Soderbery placed at 8.7 billion. Most of the devices at the time, he acknowledged were the PCs, laptops, tablets and phones in the world. But other types of devices will soon dominate the collection of the Internet of Things, such as sensors and actuators.
By the end of the decade, a nearly nine-fold increase in the volume of devices on the Internet of Things will mean a lot of infrastructure investment and market opportunities will available in this sector. And by "a lot," I mean ginourmous. In an interview with Barron's, Cisco CEO John Chambers figures that will translate to a $14-trillion industry.
Granted, Cisco has a lot of reasons to be bullish about the prospect of the Internet of Things: with product offerings in the router and switch space and a recent keen interest on building intelligent routing and application platforms right inside those devices, Cisco stands to gain a lot of business if it can get itself out in front of this newfangled Internet of Things.
It's not just Cisco talking up the Internet of Things: late last week, Morgan Stanley published a big 29-page research note on the topic that sought to at once define the Internet of Things and also quantify its size, growth and potential to make money.
See also: Cisco Hearts Internet Of Things
The Ebola virus causes an acute, serious illness which is often fatal if untreated. Ebola virus disease (EVD) first appeared in 1976 in 2 simultaneous outbreaks, one in Nzara, Sudan, and the other in Yambuku, Democratic Republic of Congo. The latter occurred in a village near the Ebola River, from which the disease takes its name.
A Virginia Tech geobiologist with collaborators from the Chinese Academy of Sciences have found evidence in the fossil record that complex multicellularity appeared in living things about 600 million years ago – nearly 60 million years before skeletal animals appeared during a huge growth spurt of new life on Earth known as the Cambrian Explosion.
The discovery published online Wednesday in the journal Nature contradicts several longstanding interpretations of multicellular fossils from at least 600 million years ago.
"This opens up a new door for us to shine some light on the timing and evolutionary steps that were taken by multicellular organisms that would eventually go on to dominate the Earth in a very visible way," said Shuhai Xiao, a professor of geobiology in the Virginia Tech College of Science. "Fossils similar to these have been interpreted as bacteria, single-cell eukaryotes, algae, and transitional forms related to modern animals such as sponges, sea anemones, or bilaterally symmetrical animals. This paper lets us put aside some of those interpretations."
In an effort to determine how, why, and when multicellularity arose from single-celled ancestors, Xiao and his collaborators looked at phosphorite rocks from the Doushantuo Formation in central Guizhou Province of South China, recovering three-dimensionally preserved multicellular fossils that showed signs of cell-to-cell adhesion, differentiation, and programmed cell death—qualities of complex multicellular eukaryotes such as animals and plants.
The discovery sheds light on how and when solo cells began to cooperate with other cells to make a single, cohesive life form. The complex multicellularity evident in the fossils is inconsistent with the simpler forms such as bacteria and single-celled life typically expected 600 million years ago.
Scientists have found the beginnings of life-bearing chemistry at the centre of the galaxy. Iso-propyl cyanide has been detected in a star-forming cloud 27,000 light-years from Earth. Its branched carbon structure is closer to the complex organic molecules of life than any previous finding from interstellar space.
The discovery suggests the building blocks of life may be widespread throughout our galaxy. Various organic molecules have previously been discovered in interstellar space, but i-propyl cyanide is the first with a branched carbon backbone.
The branched structure is important as it shows that interstellar space could be the origin of more complex branched molecules, such as amino acids, that are necessary for life on Earth. Dr Arnaud Belloche from the Max Planck Institute for Radio Astronomy is lead author of the research, which appears in the journal Science.
"Amino acids on Earth are the building blocks of proteins, and proteins are very important for life as we know it. The question in the background is: is there life somewhere else in the galaxy?"
Astronomers using data from the NASA/ESA Hubble Space Telescope, the Spitzer Space Telescope, and the Kepler Space Telescope have discovered clear skies and steamy water vapour on a planet outside our Solar System. The planet, known as HAT-P-11b, is about the size of Neptune, making it the smallest exoplanet ever on which water vapour has been detected. The results will appear in the online version of the journal Nature on 24 September 2014.
The discovery is a milestone on the road to eventually finding molecules in the atmospheres of smaller, rocky planets more akin to Earth. Clouds in the atmospheres of planets can block the view of what lies beneath them. The molecular makeup of these lower regions can reveal important information about the composition and history of a planet. Finding clear skies on a Neptune-size planet is a good sign that some smaller planets might also have similarly good visibility.
"When astronomers go observing at night with telescopes, they say 'clear skies' to mean good luck," said Jonathan Fraine of the University of Maryland, USA, lead author of the study. "In this case, we found clear skies on a distant planet. That's lucky for us because it means clouds didn't block our view of water molecules."
HAT-P-11b is a so-called exo-Neptune — a Neptune-sized planet that orbits another star. It is located 120 light-years away in the constellation of Cygnus (The Swan). Unlike Neptune, this planet orbits closer to its star, making one lap roughly every five days. It is a warm world thought to have a rocky core, a mantle of fluid and ice, and a thick gaseous atmosphere. Not much else was known about the composition of the planet, or other exo-Neptunes like it, until now.
"We set out to look at the atmosphere of HAT-P-11b without knowing if its weather would be cloudy or not," said Nikku Madhusudhan, from the University of Cambridge, UK, part of the study team. "By using transmission spectroscopy, we could use Hubble to detect water vapour in the planet. This told us that the planet didn't have thick clouds blocking the view and is a very hopeful sign that we can find and analyze more cloudless, smaller, planets in the future. It is groundbreaking!"
Before the team could celebrate they had to be sure that the water vapour was from the planet and not from cool starspots — "freckles" on the face of stars — on the parent star. Luckily, Kepler had been observing the patch of sky in which HAT-P-11b happens to lie for years. Those visible-light data were combined with targeted infrared Spitzer observations. By comparing the datasets the astronomers could confirm that the starspots were too hot to contain any water vapour, and so the vapour detected must belong to the planet.
The results from all three telescopes demonstrate that HAT-P-11b is blanketed in water vapour, hydrogen gas, and other yet-to-be-identified molecules. So in fact it is not only the smallest planet to have water vapour found in its atmosphere but is also the smallest planet for which molecules of any kind have been directly detected using spectroscopy . Theorists will be drawing up new models to explain the planet's makeup and origins.
A quantum effect in which excited atoms team up to emit an enhanced pulse of light can be turned on its head to create 'superabsorbing' systems that could make the 'ultimate camera pixel'.
'Superradiance', a phenomenon where a group of atoms charged up with energy act collectively to release a far more intense pulse of light than they would individually, is well-known to physicists. In theory the effect can be reversed to create a device that draws in light ultra-efficiently. This could be revolutionary for devices ranging from digital cameras to solar cells. But there's a problem: the advantage of this quantum effect is strongest when the atoms are already 50% charged -- and then the system would rather release its energy back as light than absorb more.
Now a team led by Oxford University theorists believes it has found the solution to this seemingly fundamental problem. Part of the answer came from biology. 'I was inspired to study ring molecules, because they are what plants use in photosynthesis to extract energy from the Sun,' said Kieran Higgins of Oxford University's Department of Materials, who led the work. 'What we then discovered is that we should be able to go beyond nature's achievement and create a 'quantum superabsorber'.'
A report of the research is published in Nature Communications.
At the core of the new design is a molecular ring, which is charged to 50% by a laser pulse in order to reach the ideal superabsorbing state. 'Now we need to keep it in that condition' notes Kieran. For this the team propose exploiting a key property of the ring structure: each time it absorbs a photon, it becomes receptive to photons of a slightly higher energy. Charging the device is like climbing a ladder whose rungs are increasingly widely spaced.
'Let's say it starts by absorbing red light from the laser,' said Kieran, 'once it is charged to 50% it now has an appetite for yellow photons, which are higher energy. And we'd like it to absorb new yellow photons, but NOT to emit the stored red photons.' This can be achieved by embedding the device into a special crystal that suppresses red light: it makes it harder for the ring to release its existing energy, so trapping it in the 50% charged state.
The final ingredient of the design is a molecular 'wire' that draws off the energy of newly absorbed photons. 'If you built a system with a capacity of 100 energy units the idea would be to 'half-charge' it to 50 units, and the wire would then 'harvest' every unit over 50,' said Kieran. 'It's like an overflow pipe in plumbing -- it is engineered to take the energy level down to 50, but no lower.' This means that the device can handle the absorption of many photons in quick succession when it is exposed to a bright source, but in the dark it will simply sit in the superabsorbing state and efficiently grab any rare passing photon.
The atmospheric conditions associated with the unprecedented drought currently afflicting California are "very likely" linked to human-caused climate change, Stanford scientists write in a new research paper.
In a new study, a team led by Stanford climate scientist Noah Diffenbaugh used a novel combination of computer simulations and statistical techniques to show that a persistent region of high atmospheric pressure hovering over the Pacific Ocean that diverted storms away from California was much more likely to form in the presence of modern greenhouse gas concentrations.
The research, published on Sept. 29 as a supplement to this month's issue of the Bulletin of the American Meteorological Society, is one of the most comprehensive studies to investigate the link between climate change and California's ongoing drought.
"Our research finds that extreme atmospheric high pressure in this region – which is strongly linked to unusually low precipitation in California – is much more likely to occur today than prior to the human emission of greenhouse gases that began during the Industrial Revolution in the 1800s," said Diffenbaugh, an associate professor of environmental Earth system science at Stanford and a senior fellow at the Stanford Woods Institute for the Environment.
The exceptional drought currently crippling California is by some metrics the worst in state history. Combined with unusually warm temperatures and stagnant air conditions, the lack of precipitation has triggered a dangerous increase in wildfires and incidents of air pollution across the state. Arecent report estimated that the water shortage would result in direct and indirect agricultural losses of at least $2.2 billion and lead to the loss of more than 17,000 seasonal and part-time jobs in 2014 alone. Such impacts prompted California Gov. Jerry Brown to declare a drought emergency and the federal government to designate all 58 California counties as "natural disaster areas."
Scientists agree that the immediate cause of the drought is a particularly stubborn "blocking ridge" over the northeastern Pacific – popularly known as the Ridiculously Resilient Ridge, or "Triple R" – that prevented winter storms from reaching California during the 2013 and 2014 rainy seasons.
In the 1960s, the Soviet Union undertook a major water diversion project on the arid plains of Kazakhstan, Uzbekistan, and Turkmenistan. The region’s two major rivers, fed by snowmelt and precipitation in faraway mountains, were used to transform the desert into farms for cotton and other crops. Before the project, the Syr Darya and the Amu Darya rivers flowed down from the mountains, cut northwest through the Kyzylkum Desert, and finally pooled together in the lowest part of the basin. The lake they made, the Aral Sea, was once the fourth largest in the world.
Although irrigation made the desert bloom, it devastated the Aral Sea. This series of images from the Moderate Resolution Imaging Spectroradiometer(MODIS) on NASA’s Terra satellite documents the changes. At the start of the series in 2000, the lake was already a fraction of its 1960 extent (black line). The Northern Aral Sea (sometimes called the Small Aral Sea) had separated from the Southern (Large) Aral Sea. The Southern Aral Sea had split into eastern and western lobes that remained tenuously connected at both ends.
By 2001, the southern connection had been severed, and the shallower eastern part retreated rapidly over the next several years. Especially large retreats in the eastern lobe of the Southern Sea appear to have occurred between 2005 and 2009, when drought limited and then cut off the flow of the Amu Darya. Water levels then fluctuated annually between 2009 and 2014 in alternately dry and wet years. Dry conditions in 2014 caused the Southern Sea’s eastern lobe to completely dry up for the first time in modern times.
As the lake dried up, fisheries and the communities that depended on them collapsed. The increasingly salty water became polluted with fertilizer and pesticides. The blowing dust from the exposed lakebed, contaminated with agricultural chemicals, became a public health hazard. The salty dust blew off the lakebed and settled onto fields, degrading the soil. Croplands had to be flushed with larger and larger volumes of river water. The loss of the moderating influence of such a large body of water made winters colder and summers hotter and drier.
In a last-ditch effort to save some of the lake, Kazakhstan built a dam between the northern and southern parts of the Aral Sea. Completed in 2005, the dam was basically a death sentence for the southern Aral Sea, which was judged to be beyond saving. All of the water flowing into the desert basin from the Syr Darya now stays in the Northern Aral Sea. Between 2005 and 2006, the water levels in that part of the lake rebounded significantly and very small increases are visible throughout the rest of the time period. The differences in water color are due to changes in sediment.
"If science and medicine are so great, then why are so many people dying of cancer?" This question has been asked many times. The answer is complex and multifaceted:
(1) Most importantly, we are dying of cancer because more of us are living long enough to die of cancer. Thanks to scientific and technological advances, Americans no longer drop dead of diphtheria (which, in 1900, was the #10 cause of death). In 1900, the average American lifespan was a paltry 46.3 years for males and 48.3 years for females. By contrast, in 2010, life expectancy was 76.2 years for men and 81.1 years for women. Of course, as Thaddeus Sim smartly points out on his blog, that doesn't mean that old people didn't exist in 1900. They did. But, a far smaller percentage of Americans made it to old age: Fewer than half of Americans made it to age 60 in 1900, but more than half of Americans made it to age 80 in 2000.
The point is that life expectancy and the percentage of Americans reaching old age are both increasing. That explains why, as a paper in The New England Journal of Medicine showed, cancer was the #8 cause of death in 1900 but the #2 cause of death in 2010.* We aren't dying of cancer because of Monsanto's pesticides and GMOs, as one lady recently said to me in an e-mail. We are dying of cancer because we are running out of things to die from. As George Johnson explained in the New York Times:
(2) We are becoming better at diagnosing cancer. That's not necessarily good news. It is still possible that an early detection will not cause you to live a moment longer. (This is a phenomenon referred to as lead time bias.) But, knowing the cause of death is better than not knowing, and we have become quite good at medical diagnostics.
(3) And, what is MOST IMPORTANT, we are indeed slowly winning the war against cancer. How so? As a 2014 paper in CA: A Cancer Journal for Clinicians explains, a combination of factors -- including early detection, preventative measures, and improved treatment -- has reduced the cancer mortality rate from a peak of 215 deaths per 100,000 people in 1991 to 172 deaths per 100,000 people in 2010.
Source: Rebecca Siegel, Jiemin Ma, Zhaohui Zou, Ahmedin Jemal. "Cancer Statistics, 2014." CA: A Cancer Journal for Clinicians 64 (1): 9-29. Jan/Feb 2014. DOI: 10.3322/caac.21208
A patient was diagnosed with Ebola in the United States for the first time, CNBC reported, citing the U.S. Centers for Disease Control and Prevention (CDC). Until Tuesday, Ebola patients had only been treated in the U.S. after being diagnosed elsewhere. The AP confirmed the news.
According to WFAA.com, the patient was being treated at a Dallas hospital. Texas Health Presbyterian Hospital of Dallas announced on Monday that one its patients was being tested for Ebola. The patient was kept in isolation and CDC officials headed to Dallas to meet with doctors there. Texas health officials believe that the chances of an outbreak in the Dallas area are very low.
he CDC gave more details about the case in a Tuesday press conference.
Dr. Thomas Frieden, Director of the CDC, reported that the infected patient was traveling from Liberia and left on September 19th, arrived in the U.S. on September 20th, but had no symptoms of the disease during that timeframe. On September 24th, the patient developed symptoms, and then sought care on September 26th. On September 28th, the patient was admitted to the hospital in Dallas. Frieden stated that he had "no doubt that we'll stop this in its tracks in the U.S."
Friedan didn’t disclose much information about the patient beyond the fact that he is visiting family in the U.S. Doctors didn't reveal his nationality -- or whether he resides in the U.S. or is a tourist. Officials did confirm that he was critically ill and that the hospital was discussing experimental therapies with the patient’s family and drug providers.
Retrotransposons are thought to be remnants of ancient viruses that infected early animals and inserted their genes into the genome long before humans evolved. Now they can only replicate themselves within the genome. Depending on where a new copy gets inserted into the genome, a jumping event can disrupt normal genes and cause disease. Often the effect is neutral, simply adding to the overall size of the genome. Very rarely the effect might be advantageous, because the added DNA can itself be a source of new regulatory elements that enhance gene expression. But the high probability of deleterious effects means natural selection favors the evolution of mechanisms to prevent jumping events.
Their findings, published September 28 in Nature, show that over evolutionary time, primate genomes have undergone repeated episodes in which mutations in jumping genes allowed them to escape repression, which drove the evolution of new repressor genes, and so on. Furthermore, their findings suggest that repressor genes that originally evolved to shut down jumping genes have since come to play other regulatory roles in the genome.
"We have basically the same 20,000 protein-coding genes as a frog, yet our genome is much more complicated, with more layers of gene regulation. This study helps explain how that came about," said Sofie Salama, a research associate at the UC Santa Cruz Genomics Institute who led the study.
Researchers at the Department of Energy’s Oak Ridge National Laboratory are the first team to sequence the entire genome of the Clostridium autoethanogenum bacterium, which is used to sustainably produce fuel and chemicals from a range of raw materials, including gases derived from biomass and industrial wastes.
Reporting in the journal Nature Physics, physicists from Imperial College London and the Friedrich-Schiller-Universität Jena, in Germany, used semiconductor nanowires made of zinc oxide and placed them on a silver surface to create ultra-fast lasers.
By using silver rather than a conventional glass surface, the scientists were able to shrink their nanowire lasers down to just 120 nanometres in diameter - around a thousandth the diameter of human hair.
The physicists were able to shrink the laser by using surface plasmons, which are wave-like motions of excited electrons found at the surface of metals. When light binds to these oscillations it can be focused much more tightly than usual.
By using surface plasmons they were able to squeeze the light into a much smaller space inside the laser, which allowed the light to interact much more strongly with the zinc oxide.
This stronger interaction accelerated the rate at which the laser could be turned on and off to ten times that of a nanowire laser using a glass surface. These are the fastest lasers recorded to date, in terms of the speed at which they can turn on and off.
Senior author Dr Rupert Oulton from the Department of Physics at Imperial College London said: “This work is so exciting because we are engineering the interaction of light and matter to drive light generation in materials much faster than it occurs naturally. When we first started working on this, I would have been happy to speed up switching speeds to a picosecond, which is one trillionth of a second. But we’ve managed to go even faster, to the point where the properties of the material itself set a speed limit.”
PhD student Robert Röder, from Friedrich-Schiller Universität Jenasaid: “This is not only ‘world record’ regarding the switching speed. Most likely we also achieved the maximum possible speed at which such a semiconductor laser can be operated.”
More than a quarter of Vietnam’s residents live in areas likely to be subject to regular floods by the end of the century. Four percent of China’s residents — 50 million people — live in the same kind of areas. Across the globe, about one person in 40 lives in a place likely to be exposed to such flooding by the end of the century, absent significant changes.
Ashkenazi Jews (AJ), identified as Jewish individuals of Central- and Eastern European ancestry, form the largest genetic isolate in the United States. AJ demonstrate distinctive genetic characteristics1, 2, including high prevalence of autosomal recessive diseases and relatively high frequency of alleles that confer a strong risk of common diseases, such as Parkinson’s disease3and breast and ovarian cancer4. Several recent studies have employed common polymorphisms5,-13 to characterize AJ as a genetically distinct population, close to other Jewish populations as well as to present-day Middle Eastern and European populations. Previous analyses of recent AJ history highlighted a narrow population bottleneck of only hundreds of individuals in late medieval times, followed by rapid expansion12, 14.
The AJ population is much larger and/or experienced a more severe bottleneck than other founder populations, such as Amish, Hutterites or Icelanders15, whose demographic histories facilitated a steady stream of genetic discoveries. This suggests the potential for cataloguing nearly all founder variants in a large extant population by sequencing a limited number of samples, who represent the diversity in the founding group (for example, ref. 16). Such a catalogue of variants can make a threefold contribution: First, it will enable clinical interpretation of personal genomes in the sizeable AJ population by distinguishing between background variation and recent, potentially more deleterious mutations. Second, it will improve disease mapping in AJ by increasing the accuracy of imputation. Third, the ability to extensively sample a population with ancient roots in the Levant is expected to provide insights regarding the histories of both Middle Eastern and European populations.
Now a team of scientists report high-depth sequencing of 128 complete genomes of AJ controls. Compared with European samples, our AJ panel has 47% more novel variants per genome and is eightfold more effective at filtering benign variants out of AJ clinical genomes. Reconstruction of recent AJ history from such data confirms a recent bottleneck of merely ≈350 individuals. Modeling of ancient histories for AJ and European populations using their joint allele frequency spectrum determines AJ to be an even admixture of European and likely Middle Eastern origins. The researchers date the split between the two ancestral populations to ≈12–25 Kyr, suggesting a predominantly Near Eastern source for the repopulation of Europe after the Last Glacial Maximum.
Lately there's been news of a radical new theory proposing that the universe began from a hyper-dimensional black hole. Most of the reports seem to stem from an article posted a while back on the Nature blog, which references the original paper. So let's have a little reality check.
No one is abandoning the big bang model. The original paper hasn't even been peer reviewed yet and the paper doesn't present a radical new theory to overturn the big bang. What the paper is actually about is higher-dimensional gravitational theory.
The standard theory of gravity (general relativity) describes our universe as a geometry of three-dimensional space with one dimension of time. This is sometimes called 3 + 1 space, and it gives a very accurate description of the universe we observe. But theorists like to play around with alternative models to see how they differ from regular general relativity. They may look at 2 + 1 space, a kind of flatland with time, or 2 + 2, with two time dimensions. There isn't necessarily anything "real" about these models, and there certainly isn't any experimental evidence to support anything other than 3 + 1 gravity, but alternative models are useful because they help us gain a deeper understanding of general relativity. In this particular paper, the authors were exploring 4 + 1 gravity. That is, a five-dimensional universe with 4 spatial dimensions and 1 time.
Back in 2000, another team of authors proposed a model where our regular 3 + 1 gravity could be treated as a brane within a larger 4 + 1 universe. It is similar to the way a 2 + 1 universe could be imagined as a 2-dimensional surface (the brane) within our 3-dimensional space. In the 2000 paper, the authors showed that a particular 4 + 1 universe with a 3 + 1 brane could give rise to the type of gravity we actually see.
The new paper takes this model one step further. In it, the authors show that 4 + 1 gravity allows for the existence of black holes. So if a 4 + 1 universe had large stars, some of those stars could collapse into a 4-dimensional "hyper black hole". Like black holes in regular general relativity, these hyper black holes would have a central "singularity" of extremely dense and hot matter/energy. The authors then went on to show that a hyper black hole with the right conditions could not only create a three-dimensional brane, but the new brane would look very similar to the early universe we actually observe.
Water was crucial to the rise of life on Earth and is also important to evaluating the possibility of life on other planets. Identifying the original source of Earth's water is key to understanding how life-fostering environments come into being and how likely they are to be found elsewhere. New work found that much of our solar system's water likely originated as ices that formed in interstellar space.
Water is found throughout our Solar System. Not just on Earth, but on icy comets and moons, and in the shadowed basins of Mercury. Water has been found included in mineral samples from meteorites, the Moon, and Mars.
Comets and asteroids in particular, being primitive objects, provide a natural "time capsule" of the conditions during the early days of our Solar System. Their ices can tell scientists about the ice that encircled the Sun after its birth, the origin of which was an unanswered question until now.
In its youth, the Sun was surrounded by a protoplanetary disk, the so-called solar nebula, from which the planets were born. But it was unclear to researchers whether the ice in this disk originated from the Sun's own parental interstellar molecular cloud, from which it was created, or whether this interstellar water had been destroyed and was re-formed by the chemical reactions taking place in the solar nebula.
"Why this is important? If water in the early Solar System was primarily inherited as ice from interstellar space, then it is likely that similar ices, along with the prebiotic organic matter that they contain, are abundant in most or all protoplanetary disks around forming stars," Alexander explained.
"But if the early Solar System's water was largely the result of local chemical processing during the Sun's birth, then it is possible that the abundance of water varies considerably in forming planetary systems, which would obviously have implications for the potential for the emergence of life elsewhere."
Over the last decade, great enthusiasm has evolved for microRNA (miRNA) therapeutics. Part of the excitement stems from the fact that a miRNA often regulates numerous related mRNAs. As such, modulation of a single miRNA allows for parallel regulation of multiple genes involved in a particular disease. While many studies have shown therapeutic efficacy using miRNA inhibitors, efforts to restore or increase the function of a miRNA have been lagging behind.
The miR‐29 family has gained a lot of attention for its clear function in tissue fibrosis. This fibroblast‐enriched miRNA family is downregulated in fibrotic diseases which induces a coordinate increase of many extracellular matrix genes. Here, we show that intravenous injection of synthetic RNA duplexes can increase miR‐29 levels in vivo for several days. Moreover, therapeutic delivery of these miR‐29 mimics during bleomycin‐induced pulmonary fibrosis restores endogenous miR‐29 function whereby decreasing collagen expression and blocking and reversing pulmonary fibrosis. Our data support the feasibility of using miRNA mimics to therapeutically increase miRNAs and indicate miR‐29 to be a potent therapeutic miRNA for treating pulmonary fibrosis.
Fatigue, weight gain, chills, hair loss, anxiety, excessive perspiration -- these symptoms are a few of the signs that the thyroid gland has gone haywire. Harnessing electron microscopy to track the inner hair cells of the cochlea in two groups of mice, new research points to an additional complication caused by an imbalance in the thyroid gland: congenital deafness.
The study, published in Mammalian Genome, was conducted by Prof. Karen B. Avraham and Dr. Amiel Dror of the Department of Human Molecular Genetics and Biochemistry at TAU's Sackler School of Medicine. Using state-of-the-art imaging, the researchers found that congenital deafness can be caused by an absence of a thyroid hormone during development.
"Since our laboratory mainly focuses on the system of the inner ear, the study of a system such as the thyroid gland was new to us and therefore challenging," said Dr. Dror. "My curiosity as to how these two systems interact together to develop normal hearing led to this multidisciplinary study."
The researchers used mouse populations to study a form of congenital deafness that affects humans. Harnessing electron microscopy at the Sackler Cellular & Molecular Imaging Center, researchers tracked the inner hair cells of the cochlea (the auditory portion of the inner ear) in two groups -- control (wild) mice and mutant (congenitally deaf) mice. Inner-ear hair bundles in the affected mice were labelled with bright colors to highlight the disorganization of the ear's hair cells.
Examination of the inner ear showed a spectrum of structural and molecular defects consistent with hypothyroidism or disrupted thyroid hormone action. The researchers' analysis of the images revealed defective formation of the mice's thyroid glands: labelled thyroid follicles did not grow or grew incompletely.
"Our work demonstrated that normal hearing fails to develop when thyroid hormone availability is insufficient as a result of a genetic mutation," said Dr. Dror. "Our model provides a platform to test therapeutic approaches in order to prevent hearing loss before it occurs. There is still long way ahead before we get to the point of practical treatments with our research, but we believe we are moving in the right direction."