Wednesday, April 28, 2010

Selected readings 4/28/10

Interesting reading and news items.

These items are also bookmarked at my Diigo account.

Cross-discipline Effort Tracks Evolution of Human Uniqueness and Modern Behavior
A panel of scientists challenges what it is to be distinctly human and retraces the evolutionary steps that bipedal apes made to attain human traits. [Scientific American, 2/26/10]

Early Humans Used Brain Power, Innovation and Teamwork to Dominate the Planet
Scholars gathered to discuss how a unique combination of human traits helped our species survive to colonize the globe. [Scientific American, 2/27/10]

Mass of the Common Quark Finally Nailed Down
It’s not every day that scientists reduce the uncertainty in a fundamental constant of nature from 30% to 1.5%, but a team of theoretical physicists claims to have done just that. Using supercomputers and mind-bogglingly complex simulations, the researchers have calculated the masses of particles called “up quarks” and “down quarks” that make up protons and neutrons with 20 times greater precision than the previous standard. [ScienceNOW, 4/2/10]

Let’s draw Feynman diagrams!
There are few things more iconic of particle physics than Feynman diagrams. These little figures of squiggly show up prominently on particle physicists’ chalkboards alongside scribbled equations. ... The simplicity of these diagrams has a certain aesthetic appeal, though as one might imagine there are many layers of meaning behind them. The good news is that’s it’s really easy to understand the first few layers and today you will learn how to draw your own Feynman diagrams and interpret their physical meaning. [US LHC Blogs, 2/14/10]

More Feynman Diagrams
We could draw lines with arrows or wiggly lines and we were only permitted to join them using intersections (vertices) of the above form. These are the rules of the game. We then said that the arrowed lines are electrons (if the arrow goes from left to right) and positrons (if the arrow points in the opposite direction) while the wiggly lines are photons. The choice of rules is what we call a “model of particle interactions,” and in particular we developed what is called quantum electrodynamics, which is physics-talk for “the theory of electrons and photons.” [US LHC Blogs, 3/7/10]

QED + μ: introducing the muon
By now we’ve already familiarized ourselves with quantum electrodynamics (QED): the theory of electrons, positrons, and photons. Now we’re going to start adding on pieces to build up the Standard Model. We’ll start with the muon. [US LHC Blogs, 4/4/10]

Free will is an illusion, biologist says
When biologist Anthony Cashmore claims that the concept of free will is an illusion, he's not breaking any new ground. At least as far back as the ancient Greeks, people have wondered how humans seem to have the ability to make their own personal decisions in a manner lacking any causal component other than their desire to "will" something. But Cashmore, Professor of Biology at the University of Pennsylvania, says that many biologists today still cling to the idea of free will, and reject the idea that we are simply conscious machines, completely controlled by a combination of our chemistry and external environmental forces. [, 3/3/10]

Did the discovery of cooking make us human?
Cooking is something we all take for granted but a new theory suggests that if we had not learned to cook food, not only would we still look like chimps but, like them, we would also be compelled to spend most of the day chewing. [BBC News, 3/2/10]

Depression’s Upside
The mystery of depression is not that it exists — the mind, like the flesh, is prone to malfunction. Instead, the paradox of depression has long been its prevalence. While most mental illnesses are extremely rare — schizophrenia, for example, is seen in less than 1 percent of the population — depression is everywhere, as inescapable as the common cold. [New York Times, 2/25/10]

Human Culture, an Evolutionary Force
As with any other species, human populations are shaped by the usual forces of natural selection, like famine, disease or climate. A new force is now coming into focus. It is one with a surprising implication — that for the last 20,000 years or so, people have inadvertently been shaping their own evolution. [New York Times, 3/1/10]

Hogan’s noise
Cosmologist Craig Hogan, in contrast, has become enamored of a noise he claims is generated by something even tinier — a minuscule graininess in the otherwise smooth structure of spacetime. Call it Hogan’s noise. Many physicists are skeptical, but if his hunch about the existence of this subatomic clatter proves correct, it could have a mind-boggling implication: that the entire universe is nothing more than a giant hologram. [Science News, 3/13/10]

Hot tip: Target inflammation to ease obesity ills
What if you could be fat but avoid heart disease or diabetes? Scientists trying to break the fat-and-disease link increasingly say inflammation is the key. In the quest to prove it, a major study is under way testing whether an anti-inflammatory drug - an old, cheap cousin of aspirin - can fight the Type 2 diabetes spurred by obesity. And intriguing new research illustrates how those yellow globs of fat lurking under the skin are more than a storage site for extra calories. They're a toxic neighborhood where inflammation appears to be born. [, 3/1/10]

Protein folding: The dark side of proteins
Almost every human protein has segments that can form amyloids, the sticky aggregates known for their role in disease. Yet cells have evolved some elaborate defences. [Nature News, 4/7/10]

'Life as we don't know it' in the universe? Start with Titan.
From the dun plains of Meridiani on Mars to the "cool Jupiter" exoplanet CoRoT-9b circling a distant star in the constellation Serpens, scientists have put a premium on finding worlds that have the potential for liquid water, which enables life on Earth. But in Titan, scientists have found a world that, some suggest, could point to an exception to the rule. Might life exist without liquid water? Increasingly, Titan is becoming the focus of a movement to consider the possible existence of "life as we don't know it." [, 4/11/10]

Mirror Neurons - The unfalsifiable theory
I recently had the pleasure of giving a lecture on mirror neurons at UC San Diego which is a very active locale for folks working on the human mirror system. I expected a lot of push-back on my critical views of mirror neurons, and I wasn't disappointed. [Talking Brains, 3/19/10]

Explained: Radiative forcing
When people talk about global warming or the greenhouse effect, the main underlying scientific concept that describes the process is radiative forcing. [, 3/10/10]

Explained: Climate sensitivity
Climate sensitivity is the term used by the Intergovernmental Panel on Climate Change (IPCC) to express the relationship between the human-caused emissions that add to the Earth's greenhouse effect -- carbon dioxide and a variety of other greenhouse gases -- and the temperature changes that will result from these emissions. [, 3/19/10]

Did Society Do It?
Language seems unlikely to have started as the solution to any one problem. Evolution can handle any single task with a more focused adaptation. There seems no reason to doubt that early Homo did use proto-speech for referring to absent things and for recruiting, but there also seems no reason to suppose it was limited to that role. [Babel's Dawn, 4/11/10]

How robots think: an introduction
In the 1960's, researchers in artificial intelligence were boldly declaring that we'd have thinking machines fully equivalent to humans in 10 years. Instead, for most of the past half-century, the only robots we saw outside of movies and labs were arms confined to factory floors and were remotely operated by humans. Building machines that behaved intelligently in the real world was harder than anyone imagined. [Nobel Intent, 3/15/10]

Hunt for the sterile neutrino heats up
Neutrinos like to keep to themselves. These ghostly particles are so reluctant to interact with ordinary matter that billions zip harmlessly through each person every day, and it takes giant, specialized detectors to capture even a handful of them. Now astronomers are finding hints of an even more elusive type of neutrino, one so shy that it could never be detected directly: the sterile neutrino. [Nature News, 3/17/10]

Explained: Regression analysis
Regression analysis. It sounds like a part of Freudian psychology. In reality, a regression is a seemingly ubiquitous statistical tool appearing in legions of scientific papers, and regression analysis is a method of measuring the link between two or more phenomena. [, 3/16/10]

A Skeptic Questions Cancer Genome Projects
Vogelstein summed up by saying that cancer has gone from "a complete black box" to something that "we really kind of understand." The "sobering" part, he said, is that he doesn't expect there will be many new genes or genetic breakthroughs. He has pinned his own hopes for preventing cancer deaths on using genetics to diagnose cancers early, when they're more treatable. [ScienceInsider, 4/23/10]

Bigger, Better Space Telescopes Following In Hubble's Footsteps
Hubble Space Telescope huggers are celebrating the iconic observatory's 20th birthday, even as scientists anticipate the next generation of bigger and more powerful successors to the famed orbital instrument. [, 4/23/10]

What Is Mathematics For? [PDF]
What mathematics education is for is not for jobs. It is to teach the race to reason. It does not, heaven knows, always succeed, but it is the best method that we have. It is not the only road to the goal, but there is none better. [Notices of the AMS, 4/27/10]

When multi-tasking, each half of the brain focuses on different goals
The part of our brain that controls out motivation to pursue our goals can divide its attention between two tasks. The left half devotes itself to one task and the right half to the other. This division of labour allows us to multi-task, but it also puts an upper limit on our abilities. [Not Exactly Rocket Science, 4/15/10]

To sleep, perchance to dream, perchance to remember
The last decade of research has clearly shown that sleep is one of the best aide memoires that we have. During this nightly time-out, our brain can rehearse information that it has picked up during the day and consolidate them into lasting memories. Wamsley’s new study supports that idea but it also shows that dreaming while you nap can strengthen our memories even further. [Not Exactly Rocket Science, 4/22/10]

The Utrecht Paradigm
There is something wrong here. If you began stopping people on the street and asked them if they thought it likely that language depends on a mixture of biological adaptations and cultural innovations, wouldn’t the first 999 out of 1000 answer yes? So what kind of knot can language scholars have tied themselves into for the news out of Utrecht to be that they too would answer yes? But that’s the case, although it looks temporary and unsustainable. [Babel's Dawn, 4/25/10]

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