نتایج جستجو برای: atacama river
تعداد نتایج: 85503 فیلتر نتایج به سال:
Global deserts occupy one-third of the Earth's surface and contribute significantly to organic carbon storage, a process at risk in dryland ecosystems that are highly vulnerable to climate-driven ecosystem degradation. The forces controlling desert ecosystem degradation rates are poorly understood, particularly with respect to the relevance of the arid-soil microbiome. Here we document correlat...
Using high-resolution microwave sky maps made by the Atacama Cosmology Telescope, we for the first time present strong evidence for motions of galaxy clusters and groups via microwave background temperature distortions due to the kinematic Sunyaev-Zel'dovich effect. Galaxy clusters are identified by their constituent luminous galaxies observed by the Baryon Oscillation Spectroscopic Survey, par...
The Atacama Large Millimeter Array, or ALMA, is an international telescope project which will be built over the coming decade in Northern Chile. With over 7000 m 2 of collecting area comprised of 64 12m antennas arrayed over baselines up to 14 km in extent, ALMA will provide images of unprecedented clarity and detail. One revolutionary feature of ALMA will be its ability to combine interferomet...
Avariety of high-quality spectroscopic studies have contributed to knowledge of the formyl cation, HCO, and its rare isotopologues, but technical limitations have previously limited precise determinations of the far-infrared, or terahertz spectrum. This study extends the microwave, millimeter, and submillimeter spectroscopy of HCO into the terahertz range. The resulting measurements and predict...
A two arm, opto-mechanical positioner mechanism is presented in this proceedings as a candidate steering system for the millimeter-wave XSPEC spectrograph. The design is well matched to the expected target density on the sky, and meeting all requirements of the Cerro Chajnantor Atacama Telescope (CCAT), site environmental conditions (e.g., operating temperature and power dissipation), and the p...
The Copernican principle remains largely unproven at Gpc radial scale and above. Generally, violations of this type cause a first-order anisotropic kinetic Sunyaev Zel'dovich (kSZ) effect. Here we show that, if large-scale radial inhomogeneities have amplitude large enough to explain the 'dark energy' phenomena, the induced kSZ power spectrum will be orders of magnitude larger than the Atacama ...
Soon robotic explorers will be able to produce more scientific data than can be transmitted or interpreted efficiently. We present a method for characterizing geology during rover traverse using autonomous data analysis techniques. The strategy detects discrete geologic features in images; distributions of these features constitute a signature that correlates with the geology of each site. Thes...
The 25 meter aperture Cornell Caltech Atacama Telescope (CCAT) will provide an enormous increase in sensitivity in the submillimeter bands compared to existing observatories, provided it can establish and maintain excellent image quality. To accomplish this at a very low cost, it is necessary to conduct accurate engineering trades, including the most effective segment and wavefront sensing and ...
The Atacama Desert in Chile is well known for being the driest and oldest desert on Earth. For these same reasons, it is also considered a good analog model of the planet Mars. Only a few decades ago, it was thought that this was a sterile place, but in the past years fascinating adaptations have been reported in the members of the three domains of life: low water availability, high UV radiatio...
Soils from the hyperarid Atacama Desert of northern Chile were sampled along an east-west elevational transect (23.75 to 24.70 degrees S) through the driest sector to compare the relative structure of bacterial communities. Analysis of denaturing gradient gel electrophoresis (DGGE) profiles from each of the samples revealed that microbial communities from the extreme hyperarid core of the deser...
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