Category Archives: Instrumentation

Lidar used to find ancient city in Honduras

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Independent: A large, unmapped, densely forested area of eastern Honduras may be the site of an ancient city called Ciudad Blanca, first reported by Hernán Cortés in 1526. Cortés never found the city and neither have any subsequent explorers. Now Steve Elkins, a filmmaker and amateur archaeologist, has teamed with archaeologists from Colorado State University to use lidar to map part of the area. Lidar creates a 3D topological map of the ground and structures on it by firing billions of pulses of laser light that can penetrate the organic forest canopy. From data collected over one week, the researchers mapped a 155-km2 area, which revealed what may be a network of plazas and pyramids. Possibly dating back to 500 CE, the city also appears to have had paved roads, parks, and advanced irrigation systems. To prevent looting, the city’s precise location has not been revealed. In partnership with the Honduran government, Elkins plans to lead a ground expedition to explore the area and make a documentary film of the effort.

“Squeezed light” used to monitor molecules inside living cells

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MIT Technology Review: A lot of internal cellular activity occurs at subnanometer scales. Such activity is hard to view with conventional imaging techniques because of diffraction, or the way that light shone on an object is deflected as it strikes tiny particles in the object. The amount of diffraction depends on a phenomenon called quantum noise—uncertainties concerning the light photons’ positions. A new technique developed by Michael Taylor of the University of Queensland, Australia, and his colleagues uses “squeezed light”—carefully manipulated photons that reduce the amount of quantum noise. The researchers were able to attain a resolution of 10 nm, a 14% improvement over conventional imaging. The technique has allowed them to monitor the motions and interactions of nanoparticles inside a living cell. By monitoring multiple areas throughout the cell, they were able to create a map of nanoparticle diffusion patterns. And because of the lower diffraction rate, they were also able to image the cell to the same resolution as conventional techniques but at much lower light intensity, and therefore less risk of damage to the cell.

Camera lens provides bug’s-eye view

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BBC: In a paper published this week in Nature, researchers at the University of Illinois at Urbana-Champaign describe a camera lens based on the compound eye of an insect. The prototype’s 180 small lenses are placed over photodetectors and stretchable electronics. That complex network is then shaped into a hemisphere and the individual signals stitched together with computer software to give a 160-degree view. The device reportedly has remarkable wide-angle capability and depth of view. The researchers envision a number of uses for such a lens, such as in surveillance devices or endoscopy tools.

Atmospheric carbon dioxide nears a troubling milestone

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Nature: In 1958, an atmospheric carbon dioxide monitoring station was established on the summit of Mauna Kea in Hawaii. It is now the longest-running such monitoring station. Initial measurements put the concentration of CO2 at 316 parts per million (ppm), not significantly higher than the 280 ppm observed before the Industrial Revolution. Within the next month, if the current upward trend continues, the facility is expected to record a daily concentration of 400 ppm, a level not seen in that area for millions of years. According to Corinne Le Quéré of the University of East Anglia in the UK, the 400-ppm level is considered the tipping point at which it will become very difficult to keep global warming in check. Although the global average daily CO2 concentration is still several years away from reaching that mark, there are no signs that the increasing concentrations are slowing down.

Large storm systems can be tracked with seismometers

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Science: Hurricane Sandy, which struck the US East Coast in 2012, produced such large, pounding ocean waves that they triggered ground motions detectable by seismological equipment across the entire continental US, reported Oner Sufri of the University of Utah and colleagues at this week’s annual meeting of the Seismological Society of America in Salt Lake City. Because such storm-induced vibrations are at lower frequencies than those produced by earthquakes, they are easily identifiable. Scientists have recently begun to comb through old seismic data sets to study storm systems that occurred before weather satellites were launched. Such information may give insight into how climate change is affecting Earth’s oceans. In addition, it can also be used to map large structures within Earth’s crust, much like x-ray computed tomography scans of the human body.

Ground-based detector in Mexico images highest-energy light

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BBC: The High-Altitude Water Cherenkov (HAWC) Observatory, being built near Puebla, Mexico, is already detecting cosmic- and gamma-ray particles in Earth’s atmosphere. HAWC will consist of 300 tanks of pure water with detectors at the bottom. As the high-energy particles enter the atmosphere, they strike molecules in the air, setting off a chain-reaction particle cascade called an extensive air shower. When those faster-than-light particles enter HAWC’s water tanks, they emit the electromagnetic equivalent of a sonic boom. It is those flashes of light that can be used to determine the type, energy, and direction of the primary cosmic- and gamma-ray particles. With just 30 tanks up and running, HAWC is already producing images, according to HAWC collaboration member Thomas Weisgarber of the University of Wisconsin–Madison during his presentation Saturday at the April meeting of the American Physical Society in Denver. The full array should be in place by 2014.

Air-dropped javelins used to monitor Antarctic glacier

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BBC: The British Antarctic Survey has developed a system of sonobuoy-like javelins that can be dropped from airplanes to place monitoring equipment in otherwise hard-to-reach places. Currently, the devices are deployed on Pine Island Glacier in Antarctica. The glacier is fast moving and crossed by chasms and precipices that make ground access impossible. It is also responsible for almost 10% of the ice that flows off the west side of the continent. The javelins are dropped from a plane with small parachutes and hit the ice at 50 m/s. Almost 3 m long and weighing 10 kg, each device has fins that prevent it from burying itself in the ice and satellite antennae and monitoring equipment that include GPS to track the glacier’s movement. Because the javelins are built to withstand the forces of the impact, 25 of the 33 that were deployed are operational; they are expected to last for up to two years. The glacier is of significant interest because satellite and aerial observations have recorded a recent thinning of the ice and an increase in movement speed. Being able to monitor the glacier will allow researchers to better understand the effects of global warming on Antarctic ice.

Microfluidic device can diagnose cancer from blood samples

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MIT Technology Review: The standard method for cancer detection is a biopsy, which can be invasive and expensive. Now, Mehmet Toner of Harvard Medical School and his colleagues have developed a device that can identify the presence of almost any sort of cancer cell in the blood stream. The microfluidic device builds on a similar earlier device that Toner’s team developed, which had to be specifically prepared to detect certain cancers and took four to five hours to complete a diagnosis. The new device is faster and works by removing all the noncancerous cells from a blood sample in a single process. White blood cells are tagged with magnetic beads covered in antibodies that recognize the white blood cells. The red blood cells, plasma, and unused magnetic beads are filtered out by microfluidic chambers, and then the white blood cells are removed by a magnetic field. What’s left is easy to examine for the presence of cancer cells. The device will be very useful for identifying the presence of circulating cancer cells, but it is unknown if it will be useful for early identification of cancer, because early-stage cancers aren’t known to produce a large number of circulating cells.

Breath analysis could serve as fingerprinting system

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BBC: Researchers are trying to determine whether one person’s breath differs enough from another’s to be used as a unique identifier, like a fingerprint. Renato Zenobi of ETH Zürich and his colleagues took samples from test subjects over a span of nine days and ran them through a mass spectrometer, a device that measures the masses of the compounds present. They found that some compounds, such as water vapor and carbon dioxide, were fairly consistent across the test subjects, but that other compounds differed and were at individualized levels and ratios. Because breath analysis is noninvasive and produces immediate results, it could be used in many situations. Once the baseline breath levels of a patient have been established, anesthesia doses could be better calibrated, and tests for doping in sports could be easily administered. Zenobi’s team is currently working to develop a system for use in diagnosing lung diseases and several forms of cancer.

Avatar director donates sub to science

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BBC: Last year, movie director James Cameron took his Deepsea Challenger submarine to the bottom of the Mariana Trench, almost 11 kilometers below the surface of the Pacific Ocean. He was the first person to have done so in 50 years, and the only one ever to do it solo. While submerged, he filmed three-dimensional images for a National Geographic movie to be released later this year. Because of a lack of funding, however, Cameron decided he would be unable to make a second dive, so he is donating the sub to the Woods Hole Oceanographic Institution. The institution, which already operates its own fleet of submersibles, plans to use components from Cameron’s vehicle, such as its lights and cameras. Cameron hopes that the Deepsea Challenger will dive again, but he says that at least its hardware and technology will be preserved.