11 research outputs found
The Robotic Multiobject Focal Plane System of the Dark Energy Spectroscopic Instrument (DESI)
A system of 5020 robotic fiber positioners was installed in 2019 on the Mayall Telescope, at Kitt Peak National Observatory. The robots automatically retarget their optical fibers every 10-20 minutes, each to a precision of several microns, with a reconfiguration time of fewer than 2 minutes. Over the next 5 yr, they will enable the newly constructed Dark Energy Spectroscopic Instrument (DESI) to measure the spectra of 35 million galaxies and quasars. DESI will produce the largest 3D map of the universe to date and measure the expansion history of the cosmos. In addition to the 5020 robotic positioners and optical fibers, DESI’s Focal Plane System includes six guide cameras, four wave front cameras, 123 fiducial point sources, and a metrology camera mounted at the primary mirror. The system also includes associated structural, thermal, and electrical systems. In all, it contains over 675,000 individual parts. We discuss the design, construction, quality control, and integration of all these components. We include a summary of the key requirements, the review and acceptance process, on-sky validations of requirements, and lessons learned for future multiobject, fiber-fed spectrographs
Clinical Trials in Head Injury
Traumatic brain injury (TBI) remains a major public health problem globally. In the United States the incidence of closed head injuries admitted to hospitals is conservatively estimated to be 200 per 100,000 population, and the incidence of penetrating head injury is estimated to be 12 per 100,000, the highest of any developed country in the world. This yields an approximate number of 500,000 new cases each year, a sizeable proportion of which demonstrate signficant long-term disabilities. Unfortunately, there is a paucity of proven therapies for this disease. For a variety of reasons, clinical trials for this condition have been difficult to design and perform. Despite promising pre-clinical data, most of the trials that have been performed in recent years have failed to demonstrate any significant improvement in outcomes. The reasons for these failures have not always been apparent and any insights gained were not always shared. It was therefore feared that we were running the risk of repeating our mistakes. Recognizing the importance of TBI, the National Institute of Neurological Disorders and Stroke (NINDS) sponsored a workshop that brought together experts from clinical, research, and pharmaceutical backgrounds. This workshop proved to be very informative and yielded many insights into previous and future TBI trials. This paper is an attempt to summarize the key points made at the workshop. It is hoped that these lessons will enhance the planning and design of future efforts in this important field of research.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/63185/1/089771502753754037.pd
The Dilemma Of Care: “Partial” Lockouts, Employment Contracts And Community Social Services In New Zealand
Recommended from our members
An integral field spectrograph for SNAP supernova studies
A well-adapted spectrograph concept has been developed for the SNAP (SuperNova/Acceleration Probe) experiment. The goal is to ensure proper identification of Type Ia supernovae and to standardize the magnitude of each candidate by determining explosion parameters. An instrument based on an integral field method with the powerful concept of imager slicing has been designed and is presented in this paper. The spectrograph concept is optimized to have very high efficiency and low spectral resolution (R {approx} 100), constant through the wavelength range (0.35-1.7{micro}m), adapted to the scientific goals of the mission
Recommended from our members
An integral field spectrograph for SNAP supernova studies
A well-adapted spectrograph concept has been developed for the SNAP (SuperNova/Acceleration Probe) experiment. The goal is to ensure proper identification of Type Ia supernovae and to standardize the magnitude of each candidate by determining explosion parameters. An instrument based on an integral field method with the powerful concept of imager slicing has been designed and is presented in this paper. The spectrograph concept is optimized to have very high efficiency and low spectral resolution (R {approx} 100), constant through the wavelength range (0.35-1.7{micro}m), adapted to the scientific goals of the mission
The BigBOSS Experiment
BigBOSS is a Stage IV ground-based dark energy experiment to study baryon
acoustic oscillations (BAO) and the growth of structure with a wide-area galaxy
and quasar redshift survey over 14,000 square degrees. It has been
conditionally accepted by NOAO in response to a call for major new
instrumentation and a high-impact science program for the 4-m Mayall telescope
at Kitt Peak. The BigBOSS instrument is a robotically-actuated, fiber-fed
spectrograph capable of taking 5000 simultaneous spectra over a wavelength
range from 340 nm to 1060 nm, with a resolution R = 3000-4800.
Using data from imaging surveys that are already underway, spectroscopic
targets are selected that trace the underlying dark matter distribution. In
particular, targets include luminous red galaxies (LRGs) up to z = 1.0,
extending the BOSS LRG survey in both redshift and survey area. To probe the
universe out to even higher redshift, BigBOSS will target bright [OII] emission
line galaxies (ELGs) up to z = 1.7. In total, 20 million galaxy redshifts are
obtained to measure the BAO feature, trace the matter power spectrum at smaller
scales, and detect redshift space distortions. BigBOSS will provide additional
constraints on early dark energy and on the curvature of the universe by
measuring the Ly-alpha forest in the spectra of over 600,000 2.2 < z < 3.5
quasars.
BigBOSS galaxy BAO measurements combined with an analysis of the broadband
power, including the Ly-alpha forest in BigBOSS quasar spectra, achieves a FOM
of 395 with Planck plus Stage III priors. This FOM is based on conservative
assumptions for the analysis of broad band power (kmax = 0.15), and could grow
to over 600 if current work allows us to push the analysis to higher wave
numbers (kmax = 0.3). BigBOSS will also place constraints on theories of
modified gravity and inflation, and will measure the sum of neutrino masses to
0.024 eV accuracy.Comment: This report is based on the BigBOSS proposal submission to NOAO in
October 2010, and reflects the project status at that time with minor update