264 research outputs found
DESI Commissioning Instrument Metrology
The Dark Energy Spectroscopic Instrument (DESI) is under construction to
measure the expansion history of the Universe using the Baryon Acoustic
Oscillation technique. The spectra of 35 million galaxies and quasars over
14000 sq deg will be measured during the life of the experiment. A new prime
focus corrector for the KPNO Mayall telescope will deliver light to 5000 fiber
optic positioners. The fibers in turn feed ten broad-band spectrographs. We
will describe the methods and results for the commissioning instrument
metrology program. The primary goals of this program are to calculate the
transformations and further develop the systems that will place fibers within
5um RMS of the target positions. We will use the commissioning instrument
metrology program to measure the absolute three axis Cartesian coordinates of
the five CCDs and 22 illuminated fiducials on the commissioning instrument
RETROCAM: A Versatile Optical Imager for Synoptic Studies
We present RETROCAM, an auxiliary CCD camera that can be rapidly inserted
into the optical beam of the MDM 2.4m telescope. The speed and ease of
reconfiguring the telescope to use the imager and a straightforward user
interface permit the camera to be used during the course of other observing
programs. This in turn encourages RETROCAM's use for a variety of monitoring
projects.Comment: 6 pages, 6 figures, Accepted by A
How sensitive is tropospheric oxidation to anthropogenic emissions?
We use a global chemistry transport model to explore how changes in anthropogenic emissions alter ozone production and tropospheric oxidizing capacity over decadal (1990–2010) and centennial timescales (1900–2100). We find that the spatial extent of O3 production and loss in the troposphere changes very little despite large projected increases in precursor emissions. While tropospheric OH shows a long-term decrease of only 20% between 1900 and 2100, there are widespread changes in distribution which alter regional oxidation capacity substantially. We show that the remote marine boundary layer remains an important net sink of O3, as greater production related to increased continental NO x emissions is outweighed by greater O3 destruction. The critical NO x level required to support net O3 production doubles between 1900 and 2100, from 28 to 55 pptv on average, preventing any large-scale shift in production regime
Gramene database in 2010: updates and extensions
Now in its 10th year, the Gramene database (http://www.gramene.org) has grown from its primary focus on rice, the first fully-sequenced grass genome, to become a resource for major model and crop plants including Arabidopsis, Brachypodium, maize, sorghum, poplar and grape in addition to several species of rice. Gramene began with the addition of an Ensembl genome browser and has expanded in the last decade to become a robust resource for plant genomics hosting a wide array of data sets including quantitative trait loci (QTL), metabolic pathways, genetic diversity, genes, proteins, germplasm, literature, ontologies and a fully-structured markers and sequences database integrated with genome browsers and maps from various published studies (genetic, physical, bin, etc.). In addition, Gramene now hosts a variety of web services including a Distributed Annotation Server (DAS), BLAST and a public MySQL database. Twice a year, Gramene releases a major build of the database and makes interim releases to correct errors or to make important updates to software and/or data
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