Another year, another round of approvals, mixed reviews and high-profile failures. We look back on which medicines made the headlines.
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Gun deaths are a serious public health issue in the United States and the scope of the problem is often difficult to illustrate. A new study published in The American Journal of Medicine lays out the risk in concrete terms. When compared to 22 other high-income nations, Americans are ten times more likely to be killed by a gun than their counterparts in the developed world. Specifically, gun homicide rates are 25 times higher in the U.S. and, while the overall suicide rate is on par with other high-income nations, the U.S. gun suicide rate is eight times higher.
In order to help put America's relationship with guns into perspective, researchers from the University of Nevada-Reno and the Harvard T.H. Chan School of Public Health analyzed mortality data gathered by the World Health Organization in 2010. Investigators found that despite having similar rates of nonlethal crimes as other high-income countries, the U.S. has much higher rates of lethal violence, mostly driven by extremely higher rates of gun-related homicides.
The study reveals some stark truths about living and dying in the United States. When compared to other high-income nations, as an American you are:
• Seven times more likely to be violently killed
• Twenty-five times more likely to be violently killed with a gun
• Six times more likely to be accidentally killed with a gun
• Eight times more likely to commit suicide using a gun
• Ten times more likely to die from a firearm death overall
Homicide is the second leading cause of death for Americans 15 to 24 years of age, and the third leading cause of death among those 25 to 34 years of age. Investigators found that for these two groups, the risk relative to their counterparts in other developed nations is alarmingly elevated. Americans 15 to 24 years of age are 49 times more likely to die from firearm homicide compared to similarly aged young people in other high-income nations. For those aged 25 to 34, the risk is 32 times higher.
A planet roughly half the size of Neptune might be 100 percent rock, making it the largest known rocky world.
When it comes to big balls of rock, exoplanet BD+20594b might have all other known worlds beat. At roughly half the diameter of Neptune, BD+20594b is 100 percent rock, researchers suggest online January 28 at arXiv.org. The planet seems to defy recent calculations that indicate a planet this large should be gassy (SN: 8/22/15, p. 32).
BD+20594b sits about 500 light-years away in the constellation Aries. The planet is about 16 times as massive as Earth but just a little over twice as wide, making its density about 8 grams per cubic centimeter, Néstor Espinoza, an astrophysicist at the Pontifical Catholic University of Chile in Santiago, and colleagues report. Earth’s density, by comparison, is 5.5 grams per cubic centimeter. The new rocky planet was discovered in 2015 with the Kepler space telescope, which looks for the silhouettes of planets passing in front of their stars.
BD+20594b is comparable to Kepler 10c, a rocky “mega Earth” reported in 2014 (SN: 7/12/14, p. 10) to be 2.4 times as wide as Earth with a hefty mass (equal to about 17 Earths). Recent measurements indicate, however, that Kepler 10c isn’t quite as “mega” or as rocky as thought — only 14 times as massive as Earth — which means that the planet is probably encased in shell of gas or water.
A Drexel University materials scientist has discovered a way to encapsulate medication to deliver it more effectively inside the body. Until now, crystals have grown in rigid, structured formations (like the snowflake) — with a web of straight lines connecting to making a grid that grows into the crystalline flake.*
But the formation of a crystal is affected by the environment in which it forms. And Christopher Li, PhD, a professor in the College of Engineering and head of the Soft Materials Lab in the Department of Materials Science & Engineering, uses this workaround to engineer hollow crystal spheres. He recently reported his finding in Nature Communications(open access).
Li was able to overcome crystal’s edge-forming tendencies by creating a tiny bubble of oil to encase water molecules. When the surfactant bubble was cooled to the appropriate temperature, the molecules inside began to crystalize. But rather than forming an angular web of connections, the molecules, instead, lined up along the interior of the oil bubble — crystallizing in a hollow, spherical shape.
Early tests indicate that Li’s “crystalsome” (named for their similarity to liposomes — tiny bubbles with the same membrane as cells that are being explored for use as biological packages for delivering drug treatments) is a few hundred times stronger than liposomes, making them a sturdier option for medicine encapsulation.
A new study of ravens' behavior when they think they're being 'spied on' suggests they possess building blocks of humans' own ability to interpret others' thoughts, hopes, and fears.
Recent studies purported to demonstrate that chimpanzees, monkeys and corvids possess a basic Theory of Mind, the ability to attribute mental states like seeing to others. However, these studies remain controversial because they share a common confound: the conspecific’s line of gaze, which could serve as an associative cue. Here, we show that ravens Corvus corax take into account the visual access of others, even when they cannot see a conspecific.
Specifically, we find that ravens guard their caches against discovery in response to the sounds of conspecifics when a peephole is open but not when it is closed. Our results suggest that ravens can generalize from their own perceptual experience to infer the possibility of being seen. These findings confirm and unite previous work, providing strong evidence that ravens are more than mere behavior-readers.
Ravens do spy on each other, it turns out, and they can infer when other birds are snooping on them. New findings, released Tuesday in a study inNature Communications, highlight just how sophisticated – and human-like – ravens' cognitive abilities are.
Researchers at Harvard-affiliated Boston Children’s Hospital have, for the first time, visualized the origins of cancer from the first affected cell and watched its spread in a live animal. Their work, published in the Jan. 29 issue of Science, could change the way scientists understand melanoma and other cancers and lead to new, early treatments before the cancer has taken hold.
“An important mystery has been why some cells in the body already have mutations seen in cancer, but do not yet fully behave like the cancer,” says the paper’s first author, Charles Kaufman, a postdoctoral fellow in the Zon Laboratory at Boston Children’s Hospital. “We found that the beginning of cancer occurs after activation of an oncogene or loss of a tumor suppressor, and involves a change that takes a single cell back to a stem cell state.”
That change, Kaufman and colleagues found, involves a set of genes that could be targeted to stop cancer from ever starting. The study imaged live zebrafish over time to track the development of melanoma. All the fish had the human cancer mutation BRAFV600E — found in most benign moles — and had also lost the tumor suppressor gene p53.
Kaufman and colleagues engineered the fish to light up in fluorescent green if a gene called crestin was turned on — a “beacon” indicating activation of a genetic program characteristic of stem cells. This program normally shuts off after embryonic development, but occasionally, in certain cells and for reasons not yet known, crestin and other genes in the program turn back on.
“Every so often we would see a green spot on a fish,” said Leonard Zon, director of the Stem Cell Research Program at Boston Children’s and senior investigator on the study. “When we followed them, they became tumors 100 percent of the time.”
When Kaufman, Zon, and colleagues looked to see what was different about these early cancer cells, they found that crestin and the other activated genes were the same ones turned on during zebrafish embryonic development — specifically, in the stem cells that give rise to the pigment cells known as melanocytes, within a structure called the neural crest.
“What’s amazing about this group of genes is that they also get turned on in human melanoma,” said Zon, who is also a member of the Harvard Stem Cell Instituteand a Howard Hughes Medical Institute investigator. “It’s a change in cell fate, back to neural crest status.”
Finding these cancer-originating cells was tedious. Wearing goggles and using a microscope with a fluorescent filter, Kaufman examined the fish as they swam around, shooting video with his iPhone. Scanning 50 fish could take two to three hours. In 30 fish, Kaufman spotted a small cluster of green-glowing cells about the size of the head of a Sharpie marker — and in all 30 cases, these spots grew into melanomas. In two cases, he was able to see on a single green-glowing cell and watch it divide and ultimately become a tumor mass.
Via Steven Krohn
Combining the capabilities of an open-source drawing tool with Google Earth maps allows researchers to visualize real-world cross-sectional data in three dimensions.
If you could fly around your research results in three dimensions, wouldn’t you like to do it? Visualizing research results properly during scientific presentations already does half the job of informing the public on the geographic framework of your research. Many scientists use Google Earth™ mapping service (V126.96.36.1991) because it’s a great interactive mapping tool for assigning geographic coordinates to individual data points, localizing a research area, and draping maps of results over Earth’s surface for displaying the results in three dimensions. Yet scientists often do not fully explore the Google Earth™ platform.
Visualizations of research results in vertical cross sections through these maps are often not shown at the same time as the maps. However, a few tutorials to display cross-sectional data in Google Earth™ do exist, and the workflow is rather simple. By importing cross-sectional data into in the open software SketchUp Make [Trimble Navigation Limited, 2016], any spatial model displaying research results can be exported to a vertical figure in Google Earth™. A website now explains an easy workflow including tips, and discusses some of the endless applications of the method. This workflow will give researchers better spatial visibility of their results and will allow for more dynamic scientific presentations.
Via Catherine Russell
Using NASA’s Fermi Space Telescope, the Very Energetic Radiation Imaging Telescope Array System (VERITAS) in Arizona, and other telescopes, astronomers have detected high-energy gamma-ray emission from an extremely distant galaxy.
The gamma rays came from PKS 1441+25, a type of galaxy called a blazar, according to two studies published in the Astrophysical Journal Letters. This galaxy lies in the constellation Boötes, approximately 7.6 billion light-years away, and has a black hole of about 70 million solar masses at its center. If placed at the center of our own Solar System, the black hole’s event horizon would extend almost to the orbit of Mars.
High-energy gamma-rays from PKS 1441+25 were detected in April 2015 and observed by a range of telescopes sensitive to different wavelengths. NASA’s Fermi telescope detected gamma rays up to 33 billion electron volts (GeV). For comparison, visible light has energies between about 2 and 3 eV.
“Detecting these very energetic gamma rays with Fermi, as well as seeing flaring at optical and X-ray energies with NASA’s Swift satellite, made it clear that PKS 1441+25 had become a good target for MAGIC,” said Dr Luigi Pacciani of the Italian National Institute for Astrophysics in Rome, who is a member of the Major Atmospheric Gamma-ray Imaging Cerenkov (MAGIC) experiment.
The MAGIC team detected gamma rays with energies ranging from 40 to 250 GeV. “Because PKS 1441+25 is so far away, we didn’t have a strong expectation of detecting gamma rays with energies this high,” said Dr Josefa Becerra Gonzalez of NASA’s Goddard Space Flight Center, a co-author of the MAGIC study.
Researchers at MIT and Texas Instruments have developed a new type of radio frequency identification (RFID) chip that is virtually impossible to hack. If such chips were widely adopted, it could mean that an identity thief couldn’t steal your credit card number or key card information by sitting next to you at a café, and high-tech burglars couldn’t swipe expensive goods from a warehouse and replace them with dummy tags.
Texas Instruments has built several prototypes of the new chip, to the researchers’ specifications, and in experiments the chips have behaved as expected. The researchers presented their research this week at the International Solid-State Circuits Conference, in San Francisco.
According to Chiraag Juvekar, a graduate student in electrical engineering at MIT and first author on the new paper, the chip is designed to prevent so-called side-channel attacks. Side-channel attacks analyze patterns of memory access or fluctuations in power usage when a device is performing a cryptographic operation, in order to extract its cryptographic key.
“The idea in a side-channel attack is that a given execution of the cryptographic algorithm only leaks a slight amount of information,” Juvekar says. “So you need to execute the cryptographic algorithm with the same secret many, many times to get enough leakage to extract a complete secret.”
One way to thwart side-channel attacks is to regularly change secret keys. In that case, the RFID chip would run a random-number generator that would spit out a new secret key after each transaction. A central server would run the same generator, and every time an RFID scanner queried the tag, it would relay the results to the server, to see if the current key was valid.
The researchers’ new chip uses a bank of 3.3-volt capacitors as an on-chip energy source. But it also features 571 1.5-volt cells that are discretely integrated into the chip’s circuitry. When the chip’s power source — the external scanner — is removed, the chip taps the 3.3-volt capacitors and completes as many operations as it can, then stores the data it’s working on in the 1.5-volt cells.
When power returns, before doing anything else the chip recharges the 3.3-volt capacitors, so that if it’s interrupted again, it will have enough power to store data. Then it resumes its previous computation. If that computation was an update of the secret key, it will complete the update before responding to a query from the scanner. Power-glitch attacks won’t work.
Because the chip has to charge capacitors and complete computations every time it powers on, it’s somewhat slower than conventional RFID chips. But in tests, the researchers found that they could get readouts from their chips at a rate of 30 per second, which should be more than fast enough for most RFID applications.
“In the age of ubiquitous connectivity, security is one of the paramount challenges we face,” says Ahmad Bahai, chief technology officer at Texas Instruments. “Because of this, Texas Instruments sponsored the authentication tag research at MIT that is being presented at ISSCC. We believe this research is an important step toward the goal of a robust, low-cost, low-power authentication protocol for the industrial Internet.”
From October 2015 to January 2016, there were almost 4,000 cases of babies born with microcephaly in Brazil. Before then, there were just 150 cases per year. The suspected culprit is a mosquito-borne virus called Zika. Officials in Colombia, Ecuador, El Salvador and Jamaica have suggested that women delay becoming pregnant. And the Centers for Disease Control and Prevention has advised pregnant women to postpone travel to countries where Zika is active. Zika virus was first detected in Zika Forest in Uganda in 1947 in a rhesus monkey, and again in 1948 in the mosquito Aedes africanus, which is the forest relative of Aedes aegypti. Aedes aegypti and Aedes albopictus can both spread Zika. Sexual transmission between people has also been reported.
The World Health Organization says it is likely that the virus will spread, as the mosquitoes that carry the virus are found in almost every country in the Americas. Zika virus was discovered almost 70 years ago, but wasn’t associated with outbreaks until 2007.
The World Health Organization (WHO) expects the Zika virus, which is spreading through the Americas, to affect between three million and four million people, a disease expert said recently. The WHO's director-general said the spread of the mosquito-borne disease had gone from a mild threat to one of alarming proportions.
Marcos Espinal, an infectious disease expert at the WHO's Americas regional office, said: "We can expect 3 to 4 million cases of Zika virus disease". He gave no time frame. There is no vaccine or treatment for Zika, which is a close cousin of dengue and chikungunya and causes mild fever, rash and red eyes. An estimated 80 percent of people infected have no symptoms, making it difficult for pregnant women to know whether they have been infected.
WHO Director-General Margaret Chan said the organization's will convene an emergency committee on Monday to help determine the level of the international response to an outbreak of the virus spreading from Brazil that is believed to be linked to severe birth defects.
"The level of alarm is extremely high," Chan told WHO executive board members at a meeting in Geneva. "As of today, cases have been reported in 23 countries and territories in the (Americas) region."
Brazil's Health Ministry said in November 2015 that Zika was linked to a fetal deformation known as microcephaly, in which infants are born with abnormally small heads Brazil has reported 3,893 suspected cases of microcephaly, the WHO said last week, more than 30 times more than in any year since 2010 and equivalent to 1-2 percent of all newborns in the state of Pernambuco, one of the worst-hit areas.
New research from Griffith University’s Centre for Quantum Dynamics is broadening perspectives on time and space. In a paper published in the prestigious journal Proceedings of the Royal Society A, Associate Professor Joan Vaccaro challenges the long-held presumption that time evolution — the incessant unfolding of the universe over time – is an elemental part of Nature.
In the paper, entitled "Quantum asymmetry between time and space," she suggests there may be a deeper origin due to a difference between the two directions of time: to the future and to the past.
"If you want to know where the universe came from and where it's going, you need to know about time," says Associate Professor Vaccaro.
"Experiments on subatomic particles over the past 50 years ago show that Nature doesn't treat both directions of time equally. "In particular, subatomic particles called K and B mesons behave slightly differently depending on the direction of time.
"When this subtle behavior is included in a model of the universe, what we see is the universe changing from being fixed at one moment in time to continuously evolving. In other words, the subtle behavior appears to be responsible for making the universe move forwards in time."
"Understanding how time evolution comes about in this way opens up a whole new view on the fundamental nature of time itself. It may even help us to better understand bizarre ideas such as travelling back in time."
According to the paper, an asymmetry exists between time and space in the sense that physical systems inevitably evolve over time whereas there is no corresponding ubiquitous translation over space. This asymmetry, long presumed to be elemental, is represented by equations of motion and conservation laws that operate differently over time and space.
However, Associate Professor Vaccaro used a "sum-over-paths formalism" to demonstrate the possibility of a time and space symmetry, meaning the conventional view of time evolution would need to be revisited.
In mathematical terms, these supervised-learning systems are given a large set of inputs and the corresponding outputs; the goal is for a computer to learn the function that will reliably transform a new input into the correct output. To do this, the computer breaks down the mystery function into a number of layers of unknown functions called sigmoid functions. These S-shaped functions look like a street-to-curb transition: a smoothened step from one level to another, where the starting level, the height of the step and the width of the transition region are not determined ahead of time.
Decades ago, researchers proved that these networks are universal, meaning that they can generate all possible functions. Other researchers later proved a number of theoretical results about the unique correspondence between a network and the function it generates. But these results assume networks that can have extremely large numbers of layers and of function nodes within each layer. In practice, neural networks use anywhere between two and two dozen layers. Because of this limitation, none of the classical results come close to explaining why neural networks and deep learning work as spectacularly well as they do.
It is the guiding principle of many applied mathematicians that if something mathematical works really well, there must be a good underlying mathematical reason for it, and we ought to be able to understand it. In this particular case, it may be that we don’t even have the appropriate mathematical framework to figure it out yet. Or, if we do, it may have been developed within an area of “pure” mathematics from which it hasn’t yet spread to other mathematical disciplines.
Another technique used in machine learning is unsupervised learning, which is used to discover hidden connections in large data sets. Let’s say, for example, that you’re a researcher who wants to learn more about human personality types. You’re awarded an extremely generous grant that allows you to give 200,000 people a 500-question personality test, with answers that vary on a scale from one to 10. Eventually you find yourself with 200,000 data points in 500 virtual “dimensions”—one dimension for each of the original questions on the personality quiz. These points, taken together, form a lower-dimensional “surface” in the 500-dimensional space in the same way that a simple plot of elevation across a mountain range creates a two-dimensional surface in three-dimensional space.
What you would like to do, as a researcher, is identify this lower-dimensional surface, thereby reducing the personality portraits of the 200,000 subjects to their essential properties—a task that is similar to finding that two variables suffice to identify any point in the mountain-range surface. Perhaps the personality-test surface can also be described with a simple function, a connection between a number of variables that is significantly smaller than 500. This function is likely to reflect a hidden structure in the data.
In the last 15 years or so, researchers have created a number of tools to probe the geometry of these hidden structures. For example, you might build a model of the surface by first zooming in at many different points. At each point, you would place a drop of virtual ink on the surface and watch how it spread out. Depending on how the surface is curved at each point, the ink would diffuse in some directions but not in others. If you were to connect all the drops of ink, you would get a pretty good picture of what the surface looks like as a whole. And with this information in hand, you would no longer have just a collection of data points. Now you would start to see the connections on the surface, the interesting loops, folds and kinks. This would give you a map for how to explore it.
These methods are already leading to interesting and useful results, but many more techniques will be needed. Applied mathematicians have plenty of work to do. And in the face of such challenges, they trust that many of their “purer” colleagues will keep an open mind, follow what is going on, and help discover connections with other existing mathematical frameworks. Or perhaps even build new ones.
Scientists at Aalto University, Finland, have made a breakthrough in physics. They succeeded in transporting heat maximally effectively ten thousand times further than ever before. The discovery may lead to a giant leap in the development of quantum computers.
Heat conduction is a fundamental physical phenomenon utilized, for example, in clothing, housing, car industry, and electronics. Thus our day-to-day life is inevitably affected by major shocks in this field. The research group, led by quantum physicist Mikko Möttönen has now made one of these groundbreaking discoveries. This new invention revolutionizes quantum-limited heat conduction which means as efficient heat transport as possible from point A to point B. This is great news especially for the developers of quantum computers.
Quantum technology is still a developing research field, but its most promising application is the super-efficient quantum computer. In the future, it can solve problems that a normal computer can never crack. The efficient operation of a quantum computer requires that it can be cooled down efficiently. At the same time, a quantum computer is prone to errors due to external noise.
Möttönen's innovation may be utilized in cooling quantum processors very efficiently and so cleverly that the operation of the computer is not disturbed.
"Our research started already in 2011 and advanced little by little. It feels really great to achieve a fundamental scientific discovery that has real practical applications", Professor Mikko Möttönen rejoices.
In the QCD Labs in Finland, Möttönen's research group succeeded in measuring quantum-limited heat transport over distances up to a meter. A meter doesn't sound very long at first, but previously scientists have been able to measure such heat transport only up to distances comparable to the thickness of a human hair.
"For computer processors, a meter is an extremely long distance. Nobody wants to build a larger processor than that", stresses Möttönen.
New Hubble telescope observations suggest that a high-velocity gas cloud was launched from the outer regions of our own galaxy around 70 million years ago. Now, the cloud is on a return collision course and is expected to plow into the Milky Way's disk in about 30 million years. Astronomers believe it will ignite a spectacular burst of star formation then.
Hubble Space Telescope astronomers are finding that the old adage "what goes up must come down" even applies to an immense cloud of hydrogen gas outside our Milky Way galaxy. The invisible cloud is plummeting toward our galaxy at nearly 700,000 miles per hour. Though hundreds of enormous, high-velocity gas clouds whiz around the outskirts of our galaxy, this so-called "Smith Cloud" is unique because its trajectory is well known. New Hubble observations suggest it was launched from the outer regions of the galactic disk, around 70 million years ago. The cloud was discovered in the early 1960s by doctoral astronomy student Gail Smith, who detected the radio waves emitted by its hydrogen.
The cloud is on a return collision course and is expected to plow into the Milky Way's disk in about 30 million years. When it does, astronomers believe it will ignite a spectacular burst of star formation, perhaps providing enough gas to make 2 million suns.
"The cloud is an example of how the galaxy is changing with time," explained team leader Andrew Fox of the Space Telescope Science Institute in Baltimore, Maryland. "It's telling us that the Milky Way is a bubbling, very active place where gas can be thrown out of one part of the disk and then return back down into another."
Killing worn-out cells helps middle-aged mice live longer, healthier lives, a new study suggests. Removing those worn-out or “senescent” cells increased the median life span of mice from 24 to 27 percent over that of rodents in which senescent cells built up normally with age, Mayo Clinic researchers report online February 3 in Nature. Clearing senescent cells also improved heart and kidney function, the researchers found.
If the results hold up in people, they could lead to an entirely new way to treat aging, says gerontology and cancer researcher Norman Sharpless at the University of North Carolina School of Medicine in Chapel Hill. Most prospective antiaging treatments would require people to take a drug for decades. Periodically zapping senescent cells might temporarily turn back the clock and improve health for people who are already aging, he says. “If this paper is right, I believe it will be one of the most important aging papers ever,” Sharpless says.
Senescent cells are ones that have ceased to divide and do their usual jobs. Instead, they hunker down and pump out inflammatory chemicals that may damage surrounding tissues and promote further aging. “They’re zombie cells,” says Steven Austad, a biogerontologist at the University of Alabama at Birmingham. ”They’ve outlived their usefulness. They’re bad.”
Cancer biologist Jan van Deursen of the Mayo Clinic in Rochester, Minn., and colleagues devised the strategy for eliminating senescent cells by making the cells commit suicide. A protein called p16 builds up in senescent cells, the researchers had previously discovered. The team hooked up a gene for a protein that causes cells to kill themselves to DNA that helps turn on p16 production, so that whenever p16 was made the suicide protein was also made.
The suicide protein needs a partner chemical to actually kill cells, though. Once mice were a year old — 40 to 60 years old in human terms — the researchers started injecting them with the partner chemical. Mice got injections about every three days for six months. Mice that got the cell-suicide cocktail were compared with genetically engineered mice that were injected with a placebo mix.
Senescent cells were easier to kill in some organs than others, the researchers found. Colon and liver senescent cells weren’t killed, for instance. But age-related declines in the function of organs in which the treatment worked — eyes, fat, heart and kidney —were slowed.
Genetic engineering and regular shots would not be feasible for use in people, but several companies are developing drugs that might clear the zombie cells from humans, Austad says. Some side effects to the treatment in mice also would be important to consider if those drugs are ever used in people. Senescent cells have previously been shown to be needed for wound healing, and mice that got the killing cocktail couldn’t repair wounds as well as those that didn’t get the treatment. Once treatment stopped, the mice were able to heal normally again. That result suggests that people undergoing senescent-cell therapy might need to stop temporarily to heal wounds from surgery or accidents.
A rapid loss of phytoplankton threatens to turn the western Indian Ocean into an “ecological desert,” a new study warns. The research reveals that phytoplankton populations in the region fell an alarming 30 percent over the last 16 years.
A decline in ocean mixing due to warming surface waters is to blame for that phytoplankton plummet, researchers propose online January 19 in Geophysical Research Letters. The mixing of the ocean’s layers ferries phytoplankton nutrients from the ocean’s dark depths up into the sunlit layers that the mini plants inhabit.
The loss of these microbes, which form the foundation of the ocean food web, may undermine the region’s ecosystem, warns study coauthor Raghu Murtugudde, an oceanographer at the University of Maryland in College Park.
“If you reduce the bottom of the food chain, it’s going to cascade,” Murtugudde says. The phytoplankton decline may be partially responsible for a 50 to 90 percent decline in tuna catch rates over the last half-century in the Indian Ocean, he says. “This is a wake-up call to look if similar things are happening elsewhere.”
In the 20th century, surface temperatures in the Indian Ocean rose about 50 percent more than the global average. Previous investigations into this ocean warming’s impact on phytoplankton suggested that populations had increased. But those studies looked at only a few years of data — not long enough to clearly identify any long-term trend.
Roxy Mathew Koll, a climate scientist at the Indian Institute of Tropical Meteorology in Pune, Murtugudde and colleagues tracked the microscopic phytoplankton from space. Phytoplankton, like land plants, are tinted green. When the sea surface is filled with phytoplankton, the water takes on a lighter, greener tinge. As the phytoplankton population thins, the water turns darker and bluer.
As many as twenty-four new species from Australian rainforests are added to the weevil genus Trigonopterus. Museum scientists Dr. Alexander Riedel, State Museum of Natural History Karlsruhe, Germany, and Rene Tanzler, Zoological State Collection Munich, Germany, have first discovered them among unidentified specimens in different beetle collections. The study is published in the open-access journal ZooKeys.
Australia is well known for its extensive deserts and savanna habitats. However, a great number of native Australian species are restricted to the wet tropical forests along the east coast of northern Queensland. These forests are also the home of the recent discoveries.
Most of the weevil species now recognised as new have already been collected in the 80s and 90s of the past century. Since then they had been resting in museum collections until German researcher Alexander Riedel had the opportunity to study them.
“Usually a delay of decades or even centuries occurs between the encounter of a new species in the field and its thorough scientific study and formal naming,” he explains. “This is due to the small number of experts who focus on species discovery,” he elaborates. “There are millions of unidentified insect specimens stored in collections around the world but only few people have the training necessary to identify those of special interest.”
An international team of biologists has discovered how specialized enzymes remodel the extremely condensed genetic material in the nucleus of cells in order to control which genes can be used. The discovery will be published in the print edition of the journal Nature on Feb. 4, 2016.
It was known that the DNA in cells is wrapped around proteins in structures called nucleosomes that resemble beads on a string, which allow the genetic material to be folded and compacted into a structure called chromatin. "We knew that the compaction into chromatin makes genes inaccessible to the cellular machinery necessary for gene expression, and we also knew that enzymes opened up the chromatin to specify which genes were accessible and could be expressed in a cell, but until now, we didn't know the mechanism by which these enzymes functioned," said B. Franklin Pugh, Evan Pugh Professor, Willaman Chair in Molecular Biology, and professor of biochemistry and molecular biology at Penn State University and one of the two corresponding authors of the paper along with Matthieu Gérard of the University of Paris-Sud in France.
The discovery was achieved by an international collaboration of scientists from the Alternative Energies and Atomic Energy Commission in France (Commissariat à l'énergie atomique et aux énergies alternatives), the National Center for Scientific Research in France (Centre national de la recherche scientifique), the University of Paris-Sud in France, Southern Medical University in Guangzhou in China, and Penn State University in the United States.
The researchers first mapped the location of several "chromatin-remodeller enzymes" across the entire genome of the embryonic stem cells of the mouse. The mapping showed that remodeller enzymes bind to particular nucleosomes "beads" at the sites along the wrapped-up DNA that are located just before the gene sequence begins. These sites are important because they are the location where the process of expressing genes begins -- where other proteins required for gene expression team up for the process of turning a gene on.
The researchers then tested how the chromatin-remodeller enzymes impact gene expression by reducing the amount of each of these enzymes in embryonic stem cells. The scientists found that some chromatin-remodeller enzymes promote gene expression, some repress gene expression, and some can do both.
"The correct expression of genes is necessary to define the identity and function of different types of cells in the course of embryonic development and adult life," said Pugh. "Chromatin-remodeller enzymes help each cell type accurately express the proper set of genes by allowing or blocking access to the critical section of DNA at the beginning of genes."
Unusual silica formations spotted by a NASA rover look a lot like structures formed by microbes around geysers on Earth.
The hunt for signs of life on Mars has been on for decades, and so far scientists have found only barren dirt and rocks. Now a pair of astronomers thinks that strangely shaped minerals inside a Martian crater could be the clue everyone has been waiting for.
In 2008, scientists announced that NASA’s Spirit rover had discovered deposits of a mineral called opaline silica inside Mars's Gusev crater. That on its own is not as noteworthy as the silica’s shape: Its outer layers are covered in tiny nodules that look like heads of cauliflower sprouting from the red dirt.
No one knows for sure how those shapes—affectionately called “micro-digitate silica protrusions”—formed. But based on recent discoveries in a Chilean desert, Steven Ruff and Jack Farmer, both of Arizona State University in Tempe, think the silica might have been sculpted by microbes. At a meeting of the American Geophysical Union in December, they made the case that these weird minerals might be our best targets for identifying evidence of past life on Mars.
If the logic holds, the silica cauliflower could go down in history as arguably the biggest discovery ever in astronomy. But biology is hard to prove, especially from millions of miles away, and Ruff and Farmer aren’t claiming victory yet. All they’re saying is that maybe these enigmatic growths are mineral greetings from ancient aliens, and someone should investigate.
Spirit found the silica protrusions near the “Home Plate” region of Gusev crater, where geologists think hot springs or geysers once scorched the red planet's surface. To understand what that long-dormant landscape used to be like, we have to look closer to home: hydrothermal regions of modern Earth that resemble Mars in its ancient past.
To that end, Ruff has twice in the past year trekked to Chile’s Atacama Desert, a high plateau west of the Andes cited as the driest non-polar place on Earth. Scientists often compare this desert to Mars, and not just poetically. It’s actually like Mars. The soil is similar, as is the extreme desert climate.
In this part of the Atacama, it rains less than 100 millimeters per year, and temperatures swing from -13°F to 113°F. With an average elevation of 13,000 feet above sea level, lots of ultraviolet radiation makes it through the thin atmosphere to the ground, akin to the punishing radiation that reaches the surface of Mars.
Just as we interpret others’ behavior and emotions by peering into our own psychology, scientists look around our planet to help them interpret Mars, find its most habitable spots and look for signs of life. While the Atacama does have breathable oxygen and evolutionarily clever foxes (which Mars does not), its environment mimics Mars’s pretty well and makes a good standin for what the red planet may have been like when it was warmer and wetter.
So when geologists see something in the Atacama or another Mars analog that matches a feature on the red planet, they reasonably conclude that the two could have formed the same way. It’s not a perfect method, but it’s the best we’ve got. “I don't think there is any way around using modern Earth analogs to test where Martian microbes may be found,” says Kurt Konhauser of the University of Alberta, who is the editor-in-chief of the journal Geobiology.
But the comparison goes further: When Ruff peered closely at El Tatio’s silica formations, he saw shapes remarkably similar to those that Spirit had seen on Mars. Fraternal cauliflower twins also exist in Yellowstone National Park in Wyoming and the Taupo Volcanic Zone in New Zealand. In both of those places, the silica bears the fossilized fingerprints of microbial life.
Since microbes sculpted the silica features in Wyoming and New Zealand, it's possible they also helped make the formations at El Tatio. And if microbes were involved with the cauliflower at El Tatio, maybe they made it grow on Mars, too.
A new study sheds light on how fruit flies get their keen sense of smell.
Duke University biologist Pelin Volkan and colleagues have identified a set of genetic control switches that interact early in a fly’s development to generate dozens of types of olfactory neurons, specialized nerve cells for smell.
The same gene network also plays a role in programming the fly neurons responsible for taste, the researchers report in the journal PLOS Genetics.
The findings do more than merely explain how a household pest distinguishes rotting vegetables from ripening fruit, the authors say. The research could be a key to understanding how the nervous systems of other animals -- including humans, whose brains have billions of neurons -- produce such a dazzling array of cell types from a modest number of genes.
Fruit flies rely on their keen sense of smell to tell the difference between good food and bad, safety and danger, potential mates and those off-limits. The tiny insects perceive this wide range of chemical cues through a diverse set of olfactory sensory neurons along their antennae. More than 2000 such neurons are organized into 50 types, each of which transmits information to a specific region of the fly’s poppy seed-sized brain.
“Each neuron type detects a very specific range of odors,” Volkan said. Certain odors from fermenting fruit, for example, activate one class of neurons, and carbon dioxide activates another.
Volkan is interested in how the many types of smell neurons come to be as a fruit fly develops from egg to an adult. Smell neurons begin as identical precursor cells, immature cells that have not yet “decided” which type of nerve cell they will become. All precursor cells have the same DNA, and how they produce one neuron type versus another was unknown.
One way to get many types of cells or proteins from the same genetic starting material is by mixing and matching different parts of one gene to produce multiple gene readouts, a phenomenon known as alternative splicing. The team’s results point to another strategy, however: using the same genes in different combinations, or “combinatorial coding.”
By tweaking different fly genes and counting how many neuron types were produced as the flies matured, the team identified a network of five genes that work together like coordinated control switches to guide the precursor cells’ transformation to mature neurons. The genes regulate each other’s activity, interacting in unique combinations to set each precursor cell on a distinct path by turning on different olfactory receptors in each cell.
The researchers found that manipulating the network had similar effects in the legs, which flies use not only to walk but also to taste. “The same basic toolkit gives rise to diverse types of neurons in completely different tissues,” said Volkan, who is also a member of the Duke Institute for Brain Sciences.
Via Integrated DNA Technologies
A team of scientists at the Karlsruhe Institute of Technology, Germany, has created a glassy carbon nanolattice with single struts shorter than 1 μm and diameters as small as 200 nm -- the smallest lattice structure yet produced.
The world’s smallest lattice is visible under the microscope only, according to the team, led by Dr. Jens Bauer. “The smallest stable lattice structure presented now was produced by the established 3D laser lithography process at first,” said Dr. Bauer, who is the lead author of a paper published online yesterday in the journal Nature Materials.
For their experiments, Dr. Bauer and his colleagues manufactured three differently sized lattices with tetrahedral unit cells with edge or strut lengths of 10, 7.5 and 5 µm. In the subsequent pyrolysis step, these polymeric microlattices were converted into carbon nanostructures in a furnace. “The objects were exposed to temperatures of around 1,650 degrees Fahrenheit (900 degrees Celsius) in a vacuum tube furnace,” Dr. Bauer and co-authors explained.
“During the pyrolysis, the unit cell sizes of our structures shrank by roughly 80% compared to the initially fabricated sizes, yielding lattices with unit cell edge lengths of 2,020 nm, 1,440nm and 970 nm, respectively.”
“The struts of the pyrolyzed lattices have elliptical cross-sections with axial diameters of 330, 270 and 225 nm and lateral diameters of 275, 235 and 205 nm, respectively, for the three different lattice sizes.”
The resulting structures were tested for stability under pressure by the researchers. “According to the results, load-bearing capacity of the lattice is very close to the theoretical limit and far above that of unstructured glassy carbon,” said team member Prof. Oliver Kraft.
“The strength-to-density ratios of the nanolattices are 6 times higher than those of reported microlattices. With a honeycomb topology, effective strengths of 1.2 GPa at 0.6 g/cm3 are achieved,” the scientists said.
Researchers have designed a material that prevents transplanted human islet cells from being attacked by the immune system in patients with Type 1 diabetes. The advance could help patients control their blood sugar without taking drugs.
Since the 1980s, a standard treatment for diabetic patients has been injections of insulin produced by genetically engineered bacteria. While effective, this type of treatment requires great effort by the patient and can generate large swings in blood sugar levels.
At the urging of JDRF director Julia Greenstein, Anderson, Langer, and colleagues set out several years ago to come up with a way to make encapsulated islet cell transplantation a viable therapeutic approach. They began by exploring chemical derivatives of alginate, a material originally isolated from brown algae. Alginate gels can be made to encapsulate cells without harming them, and also allow molecules such as sugar and proteins to move through, making it possible for cells inside to sense and respond to biological signals.
However, previous research has shown that when alginate capsules are implanted in primates and humans, scar tissue eventually builds up around the capsules, making the devices ineffective. The MIT/Children’s Hospital team decided to try to modify alginate to make it less likely to provoke this kind of immune response.
“We decided to take an approach where you cast a very wide net and see what you can catch,” says Arturo Vegas, a former MIT and Boston Children’s Hospital postdoc who is now an assistant professor at Boston University. Vegas is the first author of the Nature Biotechnology paper and co-first author of the Nature Medicine paper.
“We made all these derivatives of alginate by attaching different small molecules to the polymer chain, in hopes that these small molecule modifications would somehow give it the ability to prevent recognition by the immune system.”
After creating a library of nearly 800 alginate derivatives, the researchers performed several rounds of tests in mice and nonhuman primates. One of the best of those, known as triazole-thiomorpholine dioxide (TMTD), they decided to study further in tests of diabetic mice. They chose a strain of mice with a strong immune system and implanted human islet cells encapsulated in TMTD into a region of the abdominal cavity known as the intraperitoneal space.
The pancreatic islet cells used in this study were generated from human stem cells using a technique recently developed by Douglas Melton, a professor at Harvard University who is an author of the Nature Medicine paper. Following implantation, the cells immediately began producing insulin in response to blood sugar levels and were able to keep blood sugar under control for the length of the study, 174 days.
“The really exciting part of this was being able to show, in an immune-competent mouse, that when encapsulated these cells do survive for a long period of time, at least six months,” says Omid Veiseh, a senior postdoc at the Koch Institute and Boston Children’s hospital, co-first author of the Nature Medicine paper, and an author of the Nature Biotechnology paper. “The cells can sense glucose and secrete insulin in a controlled manner, alleviating the mice’s need for injected insulin.”
European scientists have gathered tiny fungi that take shelter in Antarctic rocks and sent them to the International Space Station. After 18 months on board in conditions similar to those on Mars, more than 60% of their cells remained intact, with stable DNA. The results provide new information for the search for life on the red planet. Lichens from the Sierra de Gredos (Spain) and the Alps (Austria) also travelled into space for the same experiment.
The McMurdo Dry Valleys, located in the Antarctic Victoria Land, are considered to be the most similar earthly equivalent to Mars. They make up one of the driest and most hostile environments on our planet, where strong winds scour away even snow and ice. Only so-called cryptoendolithic microorganisms, capable of surviving in cracks in rocks, and certain lichens can withstand such harsh climatological conditions.
A few years ago a team of European researchers travelled to these remote valleys to collect samples of two species of cryptoendolithic fungi: Cryomyces antarcticus and Cryomyces minteri. The aim was to send them to the International Space Station (ISS) for them to be subjected to Martian conditions and space to observe their responses.
The tiny fungi were placed in cells (1.4 centimeters in diameter) on a platform for experiments known as EXPOSE-E, developed by the European Space Agency to withstand extreme environments. The platform was sent in the Space Shuttle Atlantis to the ISS and placed outside the Columbus module with the help of an astronaut from the team led by Belgian Frank de Winne.
For 18 months half of the Antarctic fungi were exposed to Mars-like conditions. More specifically, this is an atmosphere with 95% CO2, 1.6% argon, 0.15% oxygen, 2.7% nitrogen and 370 parts per million of H2O; and a pressure of 1,000 pascals. Through optical filters, samples were subjected to ultra-violet radiation as if on Mars (higher than 200 nanometers) and others to lower radiation, including separate control samples.
“The most relevant outcome was that more than 60% of the cells of the endolithic communities studied remained intact after ‘exposure to Mars’, or rather, the stability of their cellular DNA was still high,” highlights Rosa de la Torre Noetzel from Spain’s National Institute of Aerospace Technology (INTA), co-researcher on the project.
Leveraging publicly available social media posts could help disaster response agencies quickly identify impacted areas in need of assistance, according to a Penn State-led team of researchers. By analyzing the September 2013 Colorado floods, researchers showed that a combination of remote sensing, Twitter and Flickr data could be used to identify flooded areas.
"FEMA (the Federal Emergency Management Agency), the Red Cross and other response agencies use social media now to disseminate relevant information to the general public," said said Guido Cervone, associate professor of geography and associate director of the Penn State's Institute for CyberScience. "We have seen here that there is potential to use social media data from community members to help identify hotspots in need of aid, especially when it is paired with remote sensing imagery of the area."
After a disaster, response teams typically prioritize rescue and aid efforts with help from imagery and other data that show what regions are affected the most. Responders commonly use satellite imagery, but this on its own has drawbacks.
"Publicly available satellite imagery for a location isn't always available in a timely manner -- sometimes it can take days before it becomes available," said Elena Sava, graduate student in geography, Penn State. "Our research focused on identifying data in non-traditional data streams that can prove mission critical for specific areas where there might be damage. We wanted to see if social media could help filling the gaps in the satellite data."
The 2013 Colorado flooding was an unprecedented event. In nine days in September, Boulder, Colo., received more than 43 centimeters, or 17 inches of rain -- nearly the amount of rainfall it normally receives in a year. Officials evacuated more than 10,000 people and had to rescue several thousand people and pets.
Because the flooding occurred in an urban setting, the researchers were able to access more than 150,000 tweets from people affected by the flooding. Using a tool called CarbonScanner, they identified clusters of posts suggesting possible locations of damage. Then, they analyzed more than 22,000 photos from the area obtained through satellites, Twitter, Flickr, the Civil Air Patrol, unmanned aerial vehicles and other sources.
For the first time ever, lab-grown Caribbean corals have integrated with wild populations and successfully reproduced, representing the first good news we’ve heard since the world plunged itself into the third global bleaching eventin recorded history.
Scientists have predicted that the damage stemming from this event will affect 38 percent of the planet’s reefs, with 12,000 square kilometres expected to die out with the next 12 months. An estimated 80 percent of all Caribbean coralshave already disappeared over the last four decades.
In an effort to address this particularly beleagured population, scientists from the international conservation group SECORE (which stands for SExual COral REproduction) have been breeding baby corals in the lab to seed out into the wild.
"In 2011, offspring of the critically endangered elkhorn coral (Acropora palmata) were reared from gametes collected in the field and were outplanted to a reef one year later," said Valerie Chamberland, a coral reef ecologist a SECORE.
Now, just a few years later, the team is seeing the (very exciting) fruits of their labour. "In four years, these branching corals have grown to a size of a soccer ball and reproduced, simultaneously with their natural population, in September 2015," says Chamberland. "This event marks the first ever successful rearing of a threatened Caribbean coral species to its reproductive age."
Elkhorn coral is one of the most distinctive species you’ll come across, and this makes it vital to the Caribbean reef it inhabits. Its huge, branching shape - elkhorns grow 5 to 10 cm per year and often reach a diameter of 3.7 metres - not only protects the shore from storm damage, but provides a spacious home for other marine life, such as lobsters and parrotfish.
Although in theory it may seem possible to divide time up into infinitely tiny intervals, the smallest physically meaningful interval of time is widely considered to be the Planck time, which is approximately 10-43 seconds. This ultimate limit means that it is not possible for two events to be separated by a time smaller than this.
But now in a new paper, physicists have proposed that the shortest physically meaningful length of time may actually be several orders of magnitude longer than the Planck time. In addition, the physicists have demonstrated that the existence of such a minimum time alters the basic equations of quantum mechanics, and as quantum mechanics describes all physical systems at a very small scale, this would change the description of all quantum mechanical systems.
The researchers, Mir Faizal at the University of Waterloo and University of Lethbridge in Canada, Mohammed M. Khalil at Alexandria University in Egypt, and Saurya Das at the University of Lethbridge, have recently published a paper called "Time crystals from minimum time uncertainty" in The European Physical Journal C.
"It might be possible that, in the universe, the minimum time scale is actually much larger than the Planck time, and this can be directly tested experimentally," Faizal explains. The Planck time is so short that no experiment has ever come close to examining it directly—the most precise tests can access a time interval down to about 10−17 seconds.
Nevertheless, there is a great deal of theoretical support for the existence of the Planck time from various approaches to quantum gravity, such as string theory, loop quantum gravity, and perturbative quantum gravity. Almost all of these approaches suggest that it is not possible to measure a length shorter than the Planck length, and by extension not possible to measure a time shorter than the Planck time, since the Planck time is defined as the time it takes light to travel a single unit of the Planck length in a vacuum.
Motivated by several recent theoretical studies, the scientists further delved into the question of the structure of time—in particular, the long-debated question of whether time is continuous or discrete. "In our paper, we have proposed that time is discrete in nature, and we have also suggested ways to experimentally test this proposal," Faizal said.
One possible test involves measuring the rate of spontaneous emission of a hydrogen atom. The modified quantum mechanical equation predicts a slightly different rate of spontaneous emission than that predicted by the unmodified equation, within a range of uncertainty. The proposed effects may also be observable in the decay rates of particles and of unstable nuclei.
Based on their theoretical analysis of the spontaneous emission of hydrogen, the researchers estimate that the minimum time may be orders of magnitude larger than the Planck time, but no greater than a certain amount, which is fixed by previous experiments. Future experiments could lower this bound on the minimum time or determine its exact value.
The scientists also suggest that the proposed changes to the basic equations of quantum mechanics would modify the very definition of time. They explain that the structure of time can be thought of as a crystal structure, consisting of discrete, regularly repeating segments.
On a more philosophical level, the argument that time is discrete suggests that our perception of time as something that is continuously flowing is just an illusion.