نتایج جستجو برای: atacama river

تعداد نتایج: 85503  

2017
Julia W Neilson Katy Califf Cesar Cardona Audrey Copeland Will van Treuren Karen L Josephson Rob Knight Jack A Gilbert Jay Quade J Gregory Caporaso Raina M Maier

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...

Journal: :Physical review letters 2012
Nick Hand Graeme E Addison Eric Aubourg Nick Battaglia Elia S Battistelli Dmitry Bizyaev J Richard Bond Howard Brewington Jon Brinkmann Benjamin R Brown Sudeep Das Kyle S Dawson Mark J Devlin Joanna Dunkley Rolando Dunner Daniel J Eisenstein Joseph W Fowler Megan B Gralla Amir Hajian Mark Halpern Matt Hilton Adam D Hincks Renée Hlozek John P Hughes Leopoldo Infante Kent D Irwin Arthur Kosowsky Yen-Ting Lin Elena Malanushenko Viktor Malanushenko Tobias A Marriage Danica Marsden Felipe Menanteau Kavilan Moodley Michael D Niemack Michael R Nolta Daniel Oravetz Lyman A Page Nathalie Palanque-Delabrouille Kaike Pan Erik D Reese David J Schlegel Donald P Schneider Neelima Sehgal Alaina Shelden Jon Sievers Cristóbal Sifón Audrey Simmons Stephanie Snedden David N Spergel Suzanne T Staggs Daniel S Swetz Eric R Switzer Hy Trac Benjamin A Weaver Edward J Wollack Christophe Yeche Caroline Zunckel

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...

2008
Alwyn Wootten

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...

2007
Valerio Lattanzi Adam Walters Brian J. Drouin John C. Pearson

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...

2014
S. C. Chapman A. Tikhomirov C. M. Bradford S. Hailey-Dunsheath

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...

Journal: :Philosophical transactions. Series A, Mathematical, physical, and engineering sciences 2011
Pengjie Zhang Albert Stebbins

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 ...

2005
David R. Thompson Trey Smith David Wettergreen

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...

2010
John Z. Lou Andy Kissil Dave C. Redding Matt C. Bradford Steve Padin David Woody

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 ...

2014
Armando Azua-Bustos Carlos González-Silva

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...

Journal: :Applied and environmental microbiology 2006
Kevin P Drees Julia W Neilson Julio L Betancourt Jay Quade David A Henderson Barry M Pryor Raina M Maier

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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