science

Statistical validation of results, as Shaffer described it, simply involves testing the null hypothesis: that the pattern you detect in your data occurs at random. If you can reject the null hypothesis—and science and medicine have settled on rejecting it when there's only a five percent or less chance that it occurred at random—then you accept that your actual finding is significant. The problem now is that we're rapidly expanding our ability to do tests. Various speakers pointed to data sources as diverse as gene expression chips and the Sloan Digital Sky Survey, which provide tens of thousands of individual data points to analyze. At the same time, the growth of computing power has meant that we can ask many questions of these large data sets at once, and each one of these tests increases the prospects than an error will occur in a study; as Shaffer put it, "every decision increases your error prospects." She pointed out that dividing data into subgroups, which can often identify susceptible subpopulations, is also a decision, and increases the chances of a spurious error. Smaller populations are also more prone to random associations. In the end, Young noted, by the time you reach 61 tests, there's a 95 percent chance that you'll get a significant result at random. And, let's face it—researchers want to see a significant result, so there's a strong, unintentional bias towards trying different tests until something pops out. Young went on to describe a study, published in JAMA, that was a multiple testing train wreck: exposures to 275 chemicals were considered, 32 health outcomes were tracked, and 10 demographic variables were used as controls. That was about 8,800 different tests, and as many as 9 million ways of looking at the data once the demographics were considered.

By combining a hurricane model and coupled ocean-atmosphere general circulation model to investigate the early Pliocene, Emanuel, Brierley and co-author Alexey Fedorov observed how vertical ocean mixing by hurricanes near the equator caused shallow parcels of water to heat up and later resurface in the eastern equatorial Pacific as part of the ocean wind-driven circulation. The researchers conclude from this pattern that frequent hurricanes in the central Pacific likely strengthened the warm pool in the eastern equatorial Pacific, which in turn increased hurricane frequency — an interaction described by Emanuel as a “two-way feedback process.”�The researchers believe that in addition to creating more hurricanes, the intense hurricane activity likely created a permanent El Nino like state in which very warm water in the eastern Pacific near the equator extended to higher latitudes. The El Nino weather pattern, which is caused when warm water replaces cold water in the Pacific, can impact the global climate by intermittently altering atmospheric circulation, temperature and precipitation patterns.The research suggests that Earth’s climate system may have at least two states — the one we currently live in that has relatively few tropical cyclones and relatively cold water, including in the eastern part of the Pacific, and the one during the Pliocene that featured warm sea surface temperatures, permanent El Nino conditions and high tropical cyclone activity.Although the paper does not suggest a direct link with current climate models, Fedorov said it is possible that future global warming could cause Earth to transition into a different equilibrium state that has more hurricanes and permanent El Nino conditions. “So far, there is no evidence in our simulations that this transition is going to occur at least in the next century. However, it’s still possible that the condition can occur in the future.”�Whether our future world is characterized by a mean state that is more El Nino-like remains one of the most important unanswered questions in climate dynamics, according to Matt Huber, a professor in Purdue University’s Department of Earth and Atmospheric Sciences. The Pliocene was a warmer time than now with high carbon dioxide levels. The present study found that hurricanes influenced by weakened atmospheric circulation — possibly related to high levels of carbon dioxide — contributed to very warm temperatures in the Pacific Ocean, which in turn led to more frequent and intense hurricanes. The research indicates that Earth’s climate may have multiple states based on this feedback cycle, meaning that the climate could change qualitatively in response to the effects of global warming.

The ability of NASA's Mars Reconnaissance Orbiter to continue charting the locations of these hidden glaciers and ice-filled valleys -- first confirmed by radar two years ago -- adds clues about how these deposits may have been left as remnants when regional ice sheets retreated. The subsurface ice deposits extend for hundreds of kilometers, or miles, in the rugged region called Deuteronilus Mensae, about halfway from the equator to the Martian north pole. Jeffrey Plaut of NASA's Jet Propulsion Laboratory, Pasadena, Calif., and colleagues prepared a map of the region's confirmed ice for presentation at this week's 41st Lunar and Planetary Science Conference near Houston. The Shallow Radar instrument on the orbiter has obtained more than 250 observations of the study area, which is about the size of California. "We have mapped the whole area with a high density of coverage," Plaut said. "These are not isolated features. In this area, the radar is detecting thick subsurface ice in many locations." The common locations are around the bases of mesas and scarps, and confined within valleys or craters. Plaut said, "The hypothesis is the whole area was covered with an ice sheet during a different climate period, and when the climate dried out, these deposits remained only where they had been covered by a layer of debris protecting the ice from the atmosphere."

The site that yielded the snake — dubbed Sanajeh indicus, or "ancient-gaped one from India" — was located near a village in Gujarat in western India. It was a rich nesting ground for sauropods known as titanosaurs, with evidence for hundreds of egg clutches, each containing about six to 12 round, spherical eggs. Two other instances of fossil snakes found with these clutches suggest the newly described serpent species made its living plundering nests for young dinosaurs. "It would have been a smorgasbord," said researcher Jason Head, a paleontologist at the University of Toronto at Mississauga. "Hundreds or thousands of defenseless baby sauropods could have supported an ecosystem of predators during the hatching season." The dinosaur eggs likely were laid along the sandy banks of a small, quiet tributary and covered afterward by the mother with a thin layer of sediment. These dinosaurs did not seem to look after their young — no evidence for adults has been found at the site. The fact the bones and delicate structures, such as eggshells and the snake's skull, are arranged in anatomical order (as they would appear in real life) points to quick entombment of a serpent caught in the act, as opposed to them all getting washed together after they died. "Burial was rapid and deep," said researcher Shanan Peters, a geologist at the University of Wisconsin. "Probably a pulse of slushy sand and mud released during a storm."

 »We’ll just have to wait for the results of the laboratory tests.« These words are familiar to many patients. It then usually takes several days for specimens to be sent to the laboratory and analyzed and for the doctor to receive the results. For many illnesses, however, a speedy diagnosis is crucial if the treatment is to be successful. In future, the patient might only have to sit in the waiting room for a few minutes until the results are ready. In a joint project, researchers from seven Fraunhofer institutes have developed a modular platform for in vitro diagnosis which enables various types of bioanalysis – of blood and saliva for example – to be conducted in the doctor’s surgery. »Thanks to its modular design our IVD platform is so flexible that it can be used for all possible bioanalytical tasks,« states Dr. Eva Ehrentreich-Förster from the Fraunhofer Institute for Biomedical Engineering (IBMT) in Potsdam-Golm.The core element of the mini-laboratory is a disposable cartridge made of plastic which can be fitted with various types of sensor. For an analysis the doctor fills the cartridge with reagents – binding agents which indicate the presence of certain substances such as antigens in the specimen material. Various tests or assays are available for different types of analysis. To perform an assay, the doctor only has to place the relevant substances in the cartridge and the test then takes place automatically. »We have optimized the assays so that up to 500 assay reactions can be conducted in parallel in a single analysis step,« explains Dr. Ehrentreich-Förster. Even in the case of complex analyses the doctor obtains a result within about 30 minutes. A new module on the reverse side of the cartridge also makes it possible to analyze the specimen material at DNA level.Once the cartridge has been prepared, the doctor places it in the measurement system. The results can be read out with either optical or electrochemical biosensors. The researchers have installed a readout window for both methods in the measurement system, which features a bypass through which the specimen is pumped.

During evolution, living species have adapted to environmental constraints according to the mechanism of natural selection; when a mutation that aids the survival (and reproduction) of an individual appears in the genome, it then spreads throughout the rest of the species until, after several hundreds or even thousands of generations, it is carried by all individuals. But does this selection, which occurs on a specific gene in the genome of a species, also occur on the same gene in neighboring species? On which set of genes has natural selection acted specifically in each species? Researchers in the Dynamique et Organisation des Génomes team at the Institut de Biologie of the Ecole Normale Supérieure (CNRS/ENS/INSERM) have studied the genome of humans and three other primate species (chimpanzee, orangutan and macaque) using bioinformatics tools. Their work consisted in comparing the entire genomes of each species in order to identify the genes having undergone selection during the past 200,000 years. The result was that a few hundred genes have recently undergone selection in each of these species. These include around 100 genes detected in man that are shared by two or three other species, which is twice as many as might be anticipated as a random phenomenon. Thus a not inconsiderable proportion of the genes involved in human adaptation are also present in the chimpanzee, orangutan or macaque, and sometimes in several species at the same time. Natural selection acts not only by distancing different species from each other when new traits appear. But by acting on the same gene, it can also give rise to the same trait in species that have already diverged, but still have a relatively similar genome. This study thus provides a clearer understanding of the group of genes that are specifically implicated in human evolution (during the past 200,000 years), as it allows the identification of those genes which did not undergo selection in another primate line. An example that has been confirmed by this study is the well-known case of the lactase gene that can metabolize lactose during adulthood (a clear advantage with the development of agriculture and animal husbandry). The researchers have also identified a group of genes involved in some neurological functions and in the development of muscles and skeleton.

The difference between pointing by the Great Ape Trust bonobos - the only ones in the world with receptive competence for spoken English - and other captive apes that make hand gestures is explained by the culture in which they were reared, according to the paper's authors: Janni Pedersen, an Iowa State University Ph.D. candidate conducting research for her dissertation at Great Ape Trust; Pär Segerdahl, a scientist from Sweden who has published several philosophical inquires into language; and William M. Fields, an ethnographer investigating language, culture and tools in non-human primates. Fields also is Great Ape Trust's director of scientific research. Because Kanzi, Panbanisha and Nyota were raised in a culture where pointing has a purpose - The Trust's hallmark Pan/Homo environment, where infant bonobos are reared with both bonobo (Pan paniscus) and human (Homo sapiens) influences - their pointing is as scientifically meaningful as their understanding of spoken English, Fields said. The pointing study supports and builds on previous research on the effect of rearing culture on cognitive capabilities, including the 40-year research corpus of Dr. Duane Rumbaugh, Dr. Sue Savage-Rumbaugh and Fields, which is the foundation of the scientific inquiry at Great Ape Trust. Those studies included the breakthrough finding that Kanzi and other bonobos with receptive competence for spoken English acquired language as human children do - by being exposed to it since infancy. The bonobos adopted finger-pointing behavior for the same reasons, because they were reared in a culture where pointing has meaning.