Turning theory into practice — or at least a demo — scientists have created an invisibility cloak. The shield, a set of metamaterial concentric rings, bends microwaves around objects. The device only works in a narrow band of frequencies, only in two dimensions and not perfectly, but it shows that the concept is, well, more than just theory.

An experimental digital camera captures images with a single pixel. Even the cheapest of mass-produced digital cameras have millions of pixels. The trick is that the light bounces off a chip containing nearly 800,000 movable microscopic mirrors. A series of 10,000 exposures with different, random arrangements of the mirrors gives a computer enough information to construct an image. The advantage is simpler hardware and much lower power use. A Physics News Update story has more details.

A gel stops surgical wound bleeding in laboratory animals within 15 seconds without causing damage. The liquid bandage, made from peptides that automatically assemble into nanofibers, promises to shorten surgical procedures and reduce the amount of blood needed by patients.

In forecasting the effects of global warming there are generally two scenarios, bad and very bad.

A study by the Northeast Climate Impacts Assessment, a collaboration between the Union of Concerned Scientists and a team of independent scientists from universities across the US, plots the effects of global warming on the Northeast in two cases: changing to clean, renewable energy sources and continuing to use fossil fuels.

In the first scenario, temperatures rise 3.5 to 6.5 degrees Fahrenheit by the end of the century, the number of days over 100 degrees in Northeast cities increases from one or two to three to nine, the number of days with snow on the ground decreases 25 percent and the frequency of extreme rainstorms increases ten percent.

In the second scenario, temperatures rise 6.5 to 12.5 degrees Fahrenheit by the end of the century, the number of days over 100 degrees in Northeast cities increases to 14 to 28 and the number of days with snow on the ground decreases by 50 percent. One-to-three-month droughts increase from every two or three years to yearly, and three-to-six-month droughts increase from none or every 15 years to once every 10 years.

A study by the National Academies shows there is no good reason for the heavy underrepresentation of women in science and engineering faculty positions at American universities.

Four times more men than women with science and engineering Ph.D.’s hold full-time faculty positions. Female faculty members are generally paid less, promoted more slowly, receive fewer honors, and hold fewer leadership positions.

The study showed that these disparities are not accounted for by biological differences or job performance.

The red-eye removal feature in Photoshop, which uses object recognition technology to identify eyes, was Adobe’s first foray into working with the content of images. Automatic content analysis is a major focus of computer vision and image processing research, and there is a long way to go before computers can reliably identify objects in photographs. Adobe is aiming to use the technology for image retrieval – say, finding every photo of Uncle Ralph – as well as editing and touching up pictures. The company’s goal is to give computers a two-year-old’s ability to understand the content of images, said Martin Newell, a Fellow at Adobe Systems, Inc.

Nifty research papers

A pair of imaging techniques sharpen blurry photographs. (Removing Camera Shake From a Single Photograph and Coded Exposure Photography: Motion Deblurring using Fluttered Shutter)

A smart thimble combines a force feedback sensor, accelerometer and position tracker to translate finger movements, including tracing the shapes of objects, into computer input. The fingertip digitizer can also turn any surface into a touch input device for computers, PDAs and cell phones. (Fingertip Digitizer: Applying Haptics and Biomechanics to Tactile Input Technology)

A crowd simulator for virtual environments uses the mathematics of particle flow rather than the compute-intensive current approach of attempting to model each person’s movements, perception and decisions. (Continuum Crowds)

The U.S. wine making industry is poised to take a big hit from global warming in the coming decades. A climate model shows that premium wine growing regions — warm areas that suffer little frost or extreme heat — could decline by as much as 81 percent by the end of the century.

In western music, certain arrangements of chords and melodies sound “right” and others don’t. Musical theorists have long employed mathematics to try to understand harmony and melody, and particularly why only some sequences of notes lead from one specific chord to another in an aesthetically acceptable manner.

An advanced mathematical analysis uses a theoretical space in which all chords are points and sequences of notes connecting chords are lines between the points. The analysis shows that western music — even dissonant avant-garde compositions — use one of only three geometrical symmetries in the notes leading from one chord to another. This geometry of chords also provides a better understanding of consonance and dissonance, differences among musical genres and strategies of particular composers.

One of the few silver linings is fading as the ominous cloud of global warming comes into clearer view. Previous research involving greenhouse experiments suggested that the damaging effects of higher temperature and lower soil moisture on agriculture from global warming could be offset by the fertilizing effect of increases in carbon dioxide. A study based on open-field experiments shows that the carbon dioxide benefit is only half as great, leaving the world with a net loss in the global warming-agriculture equation.

A study of tropical mountain glaciers in the Andes and Himalayas shows that nothing like the global-warming-driven melting of the glaciers has happened for at least 2,000 years, and temperatures in those regions have not been as high for 5,000 years. The study found that Peru’s Qori Kalis glacier retreated 10 times faster — 60 meters per year — in the last 14 years than it did during the 15 years from 1963 to 1978. The study also found that precipitation in the glacial regions has increased over the last century, proving that rising temperatures are the cause of the glacial retreat. Glacier melt is contributing to rising sea levels and threatens the water supplies of many high-altitude communities.

The study also showed an abrupt global cooling about 5,200 years ago. Because tropical climates are relatively uniform, the abrupt cooling and today’s abrupt warming demonstrate the sensitivity of the global climate.

Separately, a study of sea surface temperatures in the tropical North Atlantic proves that about half of the record temperature increase last year was due to global warming, which is 1.5 times as much as natural variation and the effects of El Niño combined. The temperature increase was a major cause of last year’s deadly hurricane activity. Several previous studies had attributed the increased warming to a 60-to-80-year natural cycle.