Selected readings 10/24/10

Interesting reading and news items.

Please leave some comments that indicate which articles you find most interesting or that identify topics you would like to read about, and I will try to include more articles of a similar nature in the future

These items are also bookmarked at my Diigo account.

The New Nu News!: There could be an extra, "sterile" neutrino out there, although cosmology places tight restrictions on that. There could be a fundamental difference between neutrinos and anti-neutrinos, which we don't (at present) understand at all. Or there could be some physics that's completely off the radar that explains this, but it looks like the good ol' standard model (and the simplest modifications to it) is woefully inadequate to explain what we're seeing. [Starts with a Bang, 9/27/10]
Primordial Magnetic Field May Permeate the Universe: Two physicists attempting to overcome some unexpected fuzziness in images of distant, supermassive black holes say they have found yet another potential big bang vestige: an extremely weak magnetic field that stretches across the universe. If scientists confirm the finding, it could help reveal the origins of magnetism in the cosmos. [ScienceNOW, 9/24/10]
The Itch of Curiosity: Curiosity is one of those personality traits that gets short scientific shrift. It strikes me as a really important mental habit - how many successful people are utterly incurious? - but it's also extremely imprecise. What does it mean to be interested in seemingly irrelevant ideas? And how can we measure that interest? While we've analyzed raw intelligence to death - scientists are even beginning to unravel the anatomy of IQ - our curiosity about the world remains mostly a mystery. [Wired, 8/3/10]
The Personality Paradox: There's an interesting new paper in Biological Psychiatry on the genetic variations underlying human personality. The study relied on a standard inventory of temperaments - novelty-seeking, harm avoidance, reward dependence and persistence - as measured in 5,117 Australian adults. What did the scientists find? Mostly nothing. The vast genetic search came up empty. [Wired, 8/9/10]
The Worm In Your Brain: So our cortex turns out to be a lot older than previously thought. The common ancestor of us and ragworms–a wormy creature that lived 600 million years ago–not only had a brain, but had an ur-cortex. And it probably used that ur-cortex to learn about its world–most likely learning about the odors it sniffed. That animal’s descendants diverged into different forms, and the ur-cortex changed along the way. Yet they still used many of the same genes their ancestor did long ago. [The Loom, 9/3/10]
Mapping the Brain on a Massive Scale: A massive new project to scan the brains of 1,200 volunteers could finally give scientists a picture of the neural architecture of the human brain and help them understand the causes of certain neurological and psychological diseases. The National Institutes of Health announced $40 million in funding this month for the five-year effort, dubbed the Human Connectome Project. Scientists will use new imaging technologies, some still under development, to create both structural and functional maps of the human brain. [Technology Review, 9/28/10]
Recipes For Limb Renewal: Bioengineers continue to refine prosthetic limbs, but they still can’t replicate the entire constellation of capabilities provided by flesh and blood. So a few determined scientists are pursuing a different solution: They are seeking the recipe for regrowing a missing limb. [Chemical & Engineering News, 8/2/10]
If low serotonin levels aren't responsible for depression, what is?: While traditional antidepressants do increase neurogenesis and relieve depression symptoms in some animal models, others show that neurogenesis and antidepressant behaviours are unrelated. Much of this debate comes down to the fact that we don't yet have a real understanding of neurogenesis, how it works, and how it is controlled both in normal brains and in the presence of antidepressants. Until we know, finding a truly effective antidepressant may remain out of reach. So while the monoamine/serotonin hypothesis for depression may be out, neurogenesis needs to step it up a little to make it in. [guardian.co.uk, 9/28/10]
A New Way to Make Stem Cells: A Harvard researcher has developed a way to make pluripotent stem cells that solves several of the major impediments to using them to treat human diseases. Derrick Rossi, an assistant professor at Harvard Medical School, created pluripotent stem cells--which can turn into virtually any other type of cell in the body--from non-stem cells without using viruses to tinker with a cell's genome, as conventional methods do. This means that Rossi's method could be substantially safer for treating disease. [Technology Review, 10/1/10]
Alien World Tour: The Exoplanets Around Star Gliese 581: The announcement Wednesday (Sept. 29) of two newfound alien planets circling the star Gliese 581 adds to the nearby solar system's intrigue, further cementing its status as a top candidate to harbor extraterrestrial life. One of the two newly discovered planets, known as Gliese 581g, is a small, Earth-like world that likely lies within its star's habitable zone - the just-right range of distances that allow liquid water to exist. Astronomers have now detected six planets orbiting Gliese 581, the most known to circle any star beyond our own sun. [Space.com, 9/29/10]
If There's Life on Alien Planet Gliese 581g, How Do We Find It?: After spending decades searching for alien planets capable of harboring life, astronomers may have found one. So how can they check to see if life actually exists on this alien world? ... One of the planet's discoverers said in a briefing yesterday that "the chances of life on this planet are 100 percent." To determine if this is true, researchers will have to scrutinize Gliese 581g from afar, searching its atmosphere for certain telltale molecules. But it might be a while before they have the tools to do this properly. [Space.com, 9/30,10]
Astronomer Seeks ET Machines: If we ever do receive a message from outer space, we’ll want to know what kind of aliens sent it. SETI researcher Seth Shostak says we shouldn’t expect them to be anything like us – in fact, they might not be biological at all, but instead, extraterrestrial machines. [Astrobiology Magazine, 10/1/10]
The Gates of Immortality: Why do cells allow some mistakes to accumulate? If evolution is such a powerful process-one that finds solutions to all manner of problems-how could there be processes or problems that can't be fixed? [The Scientist, 10/1/10]
The One True Path?: Niswender and Galli are elucidating a molecular link between mental illness and problems with how the body processes sugars. That link is part of the complex series of events that make up the insulin-signaling pathway, a crucial mechanism by which the pancreatic hormone insulin directs the transport and storage of glucose in virtually every cell type in the body. This is only one of a recent rash of discoveries about how insulin is also intricately involved in many disease processes, including the growth of cancer cells and defects in bone mass regulation. [The Scientist, 10/1/10]
A new source of CP violation?: Abazov et al. report an unexpectedly large value of the same-sign dimuon charge asymmetry. This means that they see pairs of positive muons, μ+μ+, among the debris of their proton-antiproton collisions more often than they see pairs of negative muons, μ-μ-. The key point is that their measurement violates CP symmetry, which relates the behavior of matter and antimatter particles. [Physics, 8/16/10]
Hagfish Analysis Opens Major Gap in Tree of Life: Since the 1970s, many evolutionary biologists have considered an eel-like, deep-sea-dwelling creature called the hagfish to be the closest extant relative of a last common ancestor for all backboned creatures. That made the hagfish a stand-in for a transitional species between invertebrates and higher animals, spanning a leap as dramatic as any in evolutionary history. But a new family tree based on high-powered molecular analysis lumps hagfish together with lampreys, a jawless fish that’s primitive, but very much a vertebrate. [Wired, 10/19/10]
On a quest to map the brain’s hidden territory: On a recent morning, Wedeen pulled up images created with the new technology, in which the lakes of white were crisscrossed by colorful, ropy bundles of fibers, revealing an elegant, three-dimensional architecture. Looking more like art than anatomy, these strands form the connections in the brain — the “connectome.’’ They are neural highways crucial for brain function, including thoughts, movements, and sensations. [The Boston Globe, 10/11/10]
The origin of complex life – it was all about energy: According to a new hypothesis, put forward by Nick Lane and Bill Martin, we are all natural-born gas-guzzlers. Our very existence, and that of every animal, plant and fungus, depended on an ancient partnership, forged a few billion years ago, which gave our ancestors access to unparalleled supplies of energy and allowed them to escape from the shackles of simplicity. [Not Exactly Rocket Science, 10/20/10]
The Fuel Of Evolution: Within the cells of humans and all other modern creatures are lots of tiny mitochondria, which may have been the key to the evolution of complex multicellular life billions of years ago. [InsideScience.org, 10/22/10]
Geologists revisit the Great Oxygenation Event: Why did oxygen levels spike 2.5 billion years ago, and how much oxygen was there in the atmosphere really? Why are banded iron formations made of layers only a few centimeters thick, and why did they stop forming so abruptly? If the oceans were oxygenated 2.5 billion years ago, why did multicellular life delay its appearance for another 2 billion years? And did all these changes really take place at pretty much the same time everywhere on Earth? [Physorg.com, 8/19/10]
Mirror Mirror On The Wall: Every one of the four forces of Nature we know of - gravity, electromagnetism, the weak force, and the nuclear force - all originate from slight variations of this narrative. Gauge symmetries are the origins of all the forces of Nature. For example, gravity arises from a gauge symmetry in 3D: a sphere of a gauge with its hand pointing in any direction in the full three dimensional span of space. [Schrödinger's Dog, 10/22/10]
Gravity Up Close: Scientists know how gravity works at big distances -- the inter-planetary or inter-stellar range -- but does it work the same way at the inter-atomic range? A variety of tabletop experiments are trying to explore this issue. Already some theorists say that a departure from conventional gravity behavior could hint at the existence of extra dimensions. [InsideScience.org, 10/13/10]
Cracks In The Universe: Physicists are hot on the trail of one of strangest theorized structures in the universe. A team of researchers have announced what they think are the first indirect observations of ancient cosmic strings, bizarre objects thought to have contributed to the arrangement of objects throughout the universe. [InsideScience.org, 10/11/10]