This new estimate comes from mapping the thickness of the dusty ice by the Mars Express radar instrument that has made more than 300 virtual slices through layered deposits covering the pole. The radar sees through icy layers to the lower boundary, which in places is as deep as 3.7 kilometres below the surface.
Culture
Video evidence that an extinct woodpecker is alive and well in Arkansas, USA may prove to be a case of mistaken identity. Research published today in the open access journal BMC Biology shows how fleeting images thought to be the Ivory-billed Woodpecker Campephilus principalis could be another native woodpecker species.
Tiny tremors and temblors recently discovered in fault zones from California to Japan are generated by slow-moving earthquakes that may foreshadow catastrophic seismic events, according to scientists at Stanford University and the University of Tokyo.
In a study published in the March 15 issue of the journal Nature, the research team focused on weak seismic signals known as "non-volcanic tremor" and "low-frequency earthquakes," which seismologists say may be useful in forecasting the likelihood of potentially destructive mega-quakes of magnitude 8 or higher.
Although scientists know about basic voice production—the two "vocal folds" in the larynx vibrate and pulsate airflow from the lungs—the larynx is one of the body's least understood organs.
Sound produced by vocal-fold vibration has been extensively researched, but the specifics of how airflow actually affects sound have not been shown using an animal model—until now.
For the first time, scientists of the BaBar experiment at the Department of Energy's Stanford Linear Accelerator Center (SLAC) have observed the transition of one type of particle, the neutral D-meson, into its antimatter particle. This observation will now be used as a test of the Standard Model, the current theory that best describes all the universe's luminous matter and its associated forces.
Silicon Vertex Tracker.
Using a modified ink-jet printer, a McGill University researcher is producing three-dimensional bioceramic “bones” that could one day change the way reconstructive surgery is performed.
King Alfred burned the cakes, right? Wrong. For a start they were loaves – and for another thing, the Vikings reckon their terrifying-sounding hero Ragnar Hairybreeks should take the blame for this ninth century catering disaster.
University of Leeds professor Rory McTurk says the tale of Alfred and the cakes is probably the one story we all know about the Anglo-Saxon ruler, a detail as closely woven into popular history as Robert the Bruce being inspired by a spider and King Harold getting an arrow in the eye.
Why do some individuals sacrifice their own self-interest to help others? The evolution and maintenance of cooperative behavior is a classic puzzle in evolutionary biology. In some animal societies, cooperation occurs in close-knit family groups and kin selection explains apparently selfless behavior.
How do female chimps make sure they only get the best mates? By never wanting to reproduce at the same time, insuring that none of them have to settle for less.
At a depth of 2900 kilometres, the layer between the Earth's mantle and its core has always intrigued geophysicists because they are unable to explain the seismic data it generates. Researchers in the Solid State Structure and Properties Laboratory (CNRS/Université Lille 1/Lille National School for Advanced Chemistry) have studied its deformation which influences convection movements within the mantle or even those by tectonic plates.
Multiple sclerosis, diabetes, and arthritis are among a variety of autoimmune diseases that are aggravated when one type of white blood cell, called the immune regulatory cell, malfunctions. In humans, one cause of this malfunction is when a mutation in the FOXP3 gene disables the immune cells’ ability to function.
The fact that female wasp spiders have numerous sexual contacts is something which their male partners cannot prevent. What they can do, however, is ensure that no offspring ensue from these tête à têtes with their rivals: the male spiders simply place a chastity belt on their partner while copulating. The tip of their genital breaks off during intercourse, blocking the sexual orifice of the lady spider. Biologists from the universities of Bonn and Hamburg report on this amazing mechanism in the journal ‘Behavioral Ecology’ (vol. 18, pages 174-181, 2007).
Which navy commissioned the boat that sunk off the coast of Acre 200 years ago, which battles was it involved in and how did it end up at the bottom of the sea? The recent findings of marine archaeologists at the Leon Recanati Institute for Maritime Studies of the University of Haifa may provide the answers to these questions.
Carnegie Mellon University researchers say government officials need to adopt new ways of measuring and regulating the fine particles of smoke and soot so endemic to serious health problems and the global warming crisis.
In a March 2 article published in the journal Science, professors Allen L. Robinson and Neil M. Donahue report a new conceptual model for how microscopic particles behave in the atmosphere that raises new questions about current regulations.
Wood is formed from secondary xylem tissue consisting of cells with a heavily thickened secondary cell wall that is enriched in lignin and cellulose. In contrast, primary cell walls are composed mainly of polysaccharides (including cellulose), but contain very little lignin. Wood formation occurs through a complex series of steps involving cell division and expansion and the biosynthesis of lignin and cellulose. In addition, heartwood (darker wood at the center of the trunk) forms in many tree species through a highly regulated process of programmed cell death.