Ivan Pavlov's List: Science

The organic molecules found by the team also have chlorine atoms, and include chlorobenzene and several dichloroalkanes, such as dichloroethane, dichloropropane and dichlorobutane. Chlorobenzene is the most abundant with concentrations between 150 and 300 parts-per-billion. Chlorobenzene is not a naturally occurring compound on Earth. It is used in the manufacturing process for pesticides (insecticide DDT), herbicides, adhesives, paints and rubber. Dichloropropane is used as an industrial solvent to make paint strippers, varnishes and furniture finish removers, and is classified as a carcinogen.

A definitive geological timeline shows that a series of massive volcanic explosions 66 million years ago spewed enormous amounts of climate-altering gases into the atmosphere immediately before and during the extinction event that claimed Earth's non-avian dinosaurs, according to new research from Princeton University.

A primeval volcanic range in western India known as the Deccan Traps, which were once three times larger than France, began its main phase of eruptions roughly 250,000 years before the Cretaceous-Paleogene, or K-Pg, extinction event, the researchers report in the journal Science. For the next 750,000 years, the volcanoes unleashed more than 1.1 million cubic kilometers (264,000 cubic miles) of lava. The main phase of eruptions comprised about 80-90 percent of the total volume of the Deccan Traps' lava flow and followed a substantially weaker first phase that began about 1 million years earlier.

David Baum, University of Wisconsin, says: "All agree that eukaryotes arose from a symbiotic relationship between two cell types: bacteria that became mitochondria and a host cell, archaea, or a close relative of archaea, that became the cytoplasm and nucleus. This symbiosis explains the origin of mitochondria, but what about other eukaryotic structures, most notably the nucleus?"

The Baums' inside-out theory provides a gradual path by which eukaryotic cells could have evolved. The first stage began with a bacterial cell whose outer membrane forms protrusions, which the Baums call 'blebs', that reached out from the cell. These protrusions trapped free-living mitochondria-like bacteria between them. Using the energy gained from being in close contact with bacteria (and using bacterial-derived lipids), cells were able to get bigger and expand the size of their blebs.

The sides of the blebs formed the endoplasmic reticulum and their inner surfaces formed the outer membrane of the nucleus, with the original outer membrane of the archaeon becoming what we now call the inner nuclear membrane. Finally, the fusion of blebs with one another led to the formation of the plasma membrane. The result was the eukaryotic cell as we now know it. This inside-out theory is explained in more detail using a diagram in the research article (see notes to editors).

A nine-month-long, randomized controlled trial involving 221 prepubescent children found that those who engaged in moderate-to-vigorous physical activity for at least 60 minutes a day after school saw substantial improvements in their ability to pay attention, avoid distraction and switch between cognitive tasks, researchers report in the journal Pediatrics.

Drury, a geneticist, is a pioneer in new research exploring the biological impacts of early adversity on children. She is the first scientist to show that extreme stress in infancy can biologically age a child by shortening the tips of chromosomes, known as telomeres. These caps keep chromosomes from shrinking when cells replicate. Shorter telomeres are linked to higher risks for heart disease, cognitive decline, diabetes and mental illness in adults.

The theory suggests that the transition from black hole to white hole would take place right after the initial formation of the black hole, but because gravity dilates time, outside observers would see the black hole lasting billions or trillions of years or more, depending on its size. If the authors are correct, tiny black holes that formed during the very early history of the Universe would now be ready to pop off like firecrackers and might be detected as high-energy cosmic rays or other radiation. In fact, they say, their work could imply that some of the dramatic flares commonly considered to be supernova explosions could in fact be the dying throes of tiny black holes that formed shortly after the Big Bang.

...evidence shows that healers in Peru practiced trepanation - a surgical procedure that involves removing a section of the cranial vault using a hand drill or a scraping tool - more than 1,000 years ago to treat a variety of ailments, from head injuries to heartsickness.

Scientists had thought that there was a single species of housecat-sized Brazilian tigrina. However, the molecular data now show that tigrina populations in northeastern versus southern Brazil are completely separate, with no evidence of interbreeding between them. As such, they are best described as two distinct species.

3,700 year-old store room held 2,000 liters of strong, sweet wine.

Archaeologists have unearthed what may be the oldest -- and largest -- ancient wine cellar in the Near East, containing forty jars, each of which would have held fifty liters of strong, sweet wine. The cellar was discovered in the ruined palace of a sprawling Canaanite city in northern Israel, called Tel Kabri. The site dates to about 1,700 B.C. and isn't far from many of Israel's modern-day wineries.

Results from a DNA study of a young boy's skeletal remains believed to be 24,000 years old could turn the archaeological world upside down -- it's been demonstrated that nearly 30 percent of modern Native American's ancestry came from this youngster's gene pool, suggesting First Americans came directly from Siberia, according to a research team that includes a Texas A&M University professor.

The oldest big cat fossils ever found - from a previously unknown species "similar to a snow leopard" - have been unearthed in the Himalayas.

The skull fragments of the newly-named Panthera blytheae have been dated between 4.1 and 5.95 million years old.

Their discovery in Tibet supports the theory that big cats evolved in central Asia - not Africa - and spread outward.

One of the most complete early human skulls yet found suggests that what scientists thought were three hominin species may in fact be one.

This controversial claim comes from a comparison between the anatomical features of a 1.8-million-year-old fossil skull with those of four other skulls from the same excavation site at Dmanisi, Georgia. The wide variability in their features suggests that Homo habilis, Homo rudolfensis and Homo erectus, the species so far identified as existing worldwide in that era, might represent a single species.

In our Universe, a black hole is bounded by a spherical surface called an event horizon. Whereas in ordinary three-dimensional space it takes a two-dimensional object (a surface) to create a boundary inside a black hole, in the bulk universe the event horizon of a 4D black hole would be a 3D object — a shape called a hypersphere. When Afshordi’s team modelled the death of a 4D star, they found that the ejected material would form a 3D brane surrounding that 3D event horizon, and slowly expand.

The authors postulate that the 3D Universe we live in might be just such a brane — and that we detect the brane’s growth as cosmic expansion. “Astronomers measured that expansion and extrapolated back that the Universe must have begun with a Big Bang — but that is just a mirage,” says Afshordi.

"Gears are ubiquitous in the man-made world, found in items ranging from wristwatches to car engines, but it seems that nature invented them first.

A species of plant-hopping insect, Issus coleoptratus, is the first living creature known to possess functional gears, a new study finds. The two interlocking gears on the insect's hind legs help synchronize the legs when the animal jumps."