Reality Ruled Out? - 0 views
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Understandably upset by the idea that reality does not exist without an observer, many physicists have postulated the existence of "hidden variables" that could explain the mathematical and experimental data that give rise to these bizarre conclusions. But recently, as an article in PhysicsWeb describes, an experiment run in Austria appears to dash the hopes of the hidden variables crowd.
Pliocene Hurricaines - 0 views
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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.
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The Pliocene epoch is the period in the geologic timescale that extends from 5 million to 3 million years before present. Although scientists know that the early Pliocene had carbon dioxide concentrations similar to those of today, it has remained a mystery what caused the high levels of greenhouse gas and how the Pliocene's warm conditions, including an extensive warm pool in the Pacific Ocean and temperatures that were roughly 4 degrees C higher than today's, were maintained. In a paper published February 25 in Nature, Kerry Emanuel and two colleagues from Yale University's Department of Geology and Geophysics suggest that a positive feedback between tropical cyclones - commonly called hurricanes and typhoons - and the circulation in the Pacific could have been the mechanism that enabled the Pliocene's warm climate.
The genetic footprint of natural selection - 0 views
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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.
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A further step has been taken towards our understanding of natural selection. CNRS scientists working at the Institut de Biologie of the Ecole Normale Supérieure (CNRS/ENS/INSERM) have shown that humans, and some of their primate cousins, have a common genetic footprint, i.e. a set of genes which natural selection has often tended to act upon during the past 200,000 years. This study has also been able to isolate a group of genes that distinguish us from our cousins the great apes. Its findings are published in PloS Genetics (26 February 2010 issue).
'Hella' Proposed as Official Big Number - Yahoo! News - 0 views
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To become official, "hella" would have to jump through quite a few bureaucratic hoops. It would have to pass through the Consultative Committee for Units (CCU), one of 10 advisory committees of the International Committee for Weights and Measures (CIPM). If the CCU recommends it the CIPM, that board must then decide whether to advance the cause to the General Conference on Weights and Measures (CGPM), the official authority that can make changes to the SI system. That international organization, based in France, includes members from 81 countries. "I think that for a number of reasons it's a long shot," said Ben Stein, a spokesperson for the National Institute of Standards and Technology, the U.S. organization that handles measurements. "The types of things they would consider are is it needed, does it add or reduce confusion, are the names consistent with other names associated with the prefixes?" Sendek argues that the name would honor the scientific contributions of Northern Californians, who have famously popularized the phrase "hella" to mean "a whole lot."
Parenting Style Plays Key Role In Teen Drinking : NPR - 0 views
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For teenagers, friends play a big role in the decision to take that first drink. And by the 12th grade, more than 65 percent of teens have at least experimented with alcohol. But what parents do during the high school years can also influence whether teens go on to binge drink or abuse alcohol. Researchers at Brigham Young University have found that teenagers who grow up with parents who are either too strict or too indulgent tend to binge drink more than their peers.
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For some adults, there is a tendency to go beyond the call of duty. Particularly, when they are faced with choosing to allow or not allow. Maybe the scientific explanation is to do or not to do. And the reaction isn't always the most appropriate but it is better to be safe than sorry. What is the scientific explanation for adults that don't react or react inappropriately even when it's involves saving a teenager? What is the scientific solution for those in the center of difficult situations, who are not strict or liberal? What does a mind do when it is present many times in a teenage situation and it is not the parent?
Smelling Irresistibly Good with Choice Perfumes - 1 views
Authentic perfumes are usually expensive and hard to find. Most people I know go to department stores to look for their favorite fragrances. But I find it tiresome going to malls. Only ePerfume, an...
How Does A Turbine Work? - 0 views
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A turbine is a machine used to convert energy generated by moving liquid, gas or air into work. For example, the energy produced by fast flowing water is made to spin a rotating shaft by pushing on the angled blades set around a wheel mounted on the shaft, and this action produces the required work. ...
What is an Avalanche Diode and How Does It work? - 0 views
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How Does Solar Work? - 1 views
The amount of sunlight that reaches Earth's surface in just more than an hour and a half might provide enough energy for the whole planet for an entire year. These include photovoltaic (PV) panels ...
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