Exactly what happened 30,000–50,000 years ago still vexes archaeologists because the period is right at the limit of accurate radiocarbon dating. The technique is based on measuring the steady loss of radioactive carbon-14 molecules in organic remains. But after 30,000 years, 98% of the isotope is gone and younger carbon molecules are starting to infiltrate bones, making remains seem younger than they are. This means that dates for the final Neanderthals and for the first human occupations of Europe have been unreliable, fomenting the debate.
But over the past decade, Higham and his team have developed techniques that provide more accurate readings in bones up to 55,000 years old (see Nature 485, 27–29; 2012). First, they use a chemical pretreatment to remove the contaminating carbon from the collagen in bones, then they measure the minuscule amounts of radiocarbon using a particle accelerator.
Amid a neuroscience debate about how people and animals focus on distinct objects within cluttered scenes, some of the newest and best evidence comes from the way bats “see” with their ears, according to a new paper in the Journal of Experimental Biology. In fact, the perception process in question could improve sonar and radar technology.
Bats demonstrate remarkable skill in tracking targets such as bugs through the trees in the dark of night. James Simmons, professor of neuroscience at Brown University, the review paper’s author, has long sought to explain how they do that.
It turns out that experiments in Simmons’ lab point to the “temporal binding hypothesis” as an explanation. The hypothesis proposes that people and animals focus on objects versus the background when a set of neurons in the brain attuned to features of an object all respond in synchrony, as if shouting in unison, “Yes, look at that!” When the neurons do not respond together to an object, the hypothesis predicts, an object is relegated to the perceptual background.
By using many web services you have entered into an agreement to supply a lot of personal information to parties that use it internally and market it. XRay is a project at Columbia that intends to track some of this beginning with Gmail, YouTube and Amazon and expanding in the future.
The Web can be a black box. When a user sees an ad about spiritual meditation methods, she may not realize that she's seeing that ad because she recently received an email about depression or cancer. We are seeking to change that, and in doing so bring more transparency to the Web.
For this, we developed XRay, a new tool that reveals which data in a web account, such as emails, searches, or viewed products, are being used to target which outputs, such as ads, recommended products, or prices. It can increase end-user awareness about what the services they use do with their data, and it can enable auditors and watchdogs with the necessary tools to keep the Web in check.
Currently, XRay can reveal some forms of targeting for Gmail ads, Amazon product recommendations, and YouTube video recommendations. However, XRay's core mechanisms are largely service-agnostic, providing the necessary building blocks that we hope will enable a new generation of auditing tools that will help lift the curtain on how users' personal data is being used.
Using our XRay Gmail prototype, we found some pretty interesting examples of data uses, such as a number of ads targeting depression, cancer, and other illnesses. We also saw quite a few subprime loan ads for used cars that targeted debt, loan, or borrow keywords in users' inboxes.
I've mentioned Doug Rouch's work with the Urban Food Initiative that makes use of good food that would otherwise be discarded. Here is a paper in JAMA Pediatrics that offers more commentary (outside their paywall)
In the Central African rain forest, several groups of hunter-gatherers are significantly shorter than their agricultural neighbors are. Both the Batwa people in the east and the Baka in the west are commonly referred to as pygmies.
But exactly what factors were contributing to their reduced height wasn't clear. By analyzing the genomes of the Batwa and the Baka, and comparing them with the genomes of their average-height neighbors, the researchers were able to show that these two groups of humans showed variations in the region of the genome that codes for human growth hormone receptors and bone formation.
aximilian Schich, an art historian at the University of Texas at Dallas, and his colleagues used the Google-owned knowledge base, Freebase, to find 120,000 individuals who were notable enough in their life-times that the dates and locations of their births and deaths were recorded.
The list includes people ranging from Solon, the Greek lawmaker and poet, who was born in 637 bc in Athens, and died in 557 bc in Cyprus, to Jett Travolta — son of the actor John Travolta — who was born in 1992 in Los Angeles, California, and died in 2009 in the Bahamas.
The team used those data to create a movie that starts in 600 bc and ends in 2012. Each person’s birth place appears on a map of the world as a blue dot and their death as a red dot. The result is a way to visualize cultural history — as a city becomes more important, more notable people die there. The work that the animated map is based on was reported on 31 July in Science1.
The animation reflects some of what was known already. Rome gave way to Paris as a cultural centre, which was eventually overtaken by Los Angeles and New York. But it also puts figures and dates on these shifts — and allows for precise comparisons. For example, the data suggest that Paris overtook Rome as a cultural hub in 1789.