62 research outputs found
Detecting z > 2 Type IIn Supernovae
Type IIn supernovae (SNe IIn) dominate the brightest supernova events in
observed FUV flux (~1200-2000A). We show that multi-band, multi-epoch optical
surveys complete to m_r = 27 can detect the FUV emission of ~25 z > 2 SNe IIn
deg^-2 yr^-1 rest-frame (~10 SNe IIn deg^-2 yr^-1 observed-frame) to 4 sigma
using a technique monitoring color-selected galaxies. Moreover, the strength
and evolution of the bright emission lines observed in low redshift SNe IIn
imply that the Ly-a emission features in ~70% of z > 2 SNe IIn are above
8m-class telescope spectroscopic thresholds for ~2 yr rest-frame. As a result,
existing facilities have the capability to both photometrically detect and
spectroscopically confirm z > 2 SNe IIn and pave the way for efficient searches
by future 8m-class survey and 30m-class telescopes. The method presented here
uses the sensitivities and wide-field capabilities of current optical
instruments and exploits (1) the efficiency of z > 2 galaxy color-selection
techniques, (2) the intrinsic brightness distribution ( = -19.0 +/-0.9)
and blue profile of SNe IIn continua, (3) the presence of extremely bright,
long-lived emission features, and (4) the potential to detect blueshifted SNe
Ly-a emission shortward of host galaxy Ly-a features.Comment: 26 pages (pre-print), 6 figures, accepted Ap
An Ejectable Data Recorder Subsystem for the Ascent Abort-2 Test Flight of the Orion Launch Abort System
The Ejectable Data Record (EDR) subsystem was a unique development opportunity at NASA with challenges that necessitated innovation. EDR employed a skunkworks development approach in which we designed, built, and delivered 47 end items, not including ground support equipment. We used as many COTS components as possible, we looked for process efficiencies to meet our tight deadlines, and the EDR team was involved in the flight operations of the AA-2 test flight and responsible for the recovery operations of the ejected payloads. This paper will discuss the design and development of the EDR subsystem, as well as the results of the system performance during the AA-2 test flight
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Rangewide genetic analysis of Lesser Prairie-Chicken reveals population structure, range expansion, and possible introgression
The distribution of the Lesser Prairie-Chicken (Tympanuchus pallidicinctus) has been markedly reduced due to loss and fragmentation of habitat. Portions of the historical range, however, have been recolonized and even expanded due to planting of conservation reserve program (CRP) fields that provide favorable vegetation structure for Lesser Prairie-Chickens. The source population(s) feeding the range expansion is unknown, yet has resulted in overlap between Lesser and Greater Prairie-Chickens (T. cupido) increasing the potential for hybridization. Our objectives were to characterize connectivity and genetic diversity among populations, identify source population(s) of recent range expansion, and examine hybridization with the Greater Prairie-Chicken. We analyzed 640 samples from across the range using 13 microsatellites. We identified three to four populations corresponding largely to ecoregions. The Shinnery Oak Prairie and Sand Sagebrush Prairie represented genetically distinct populations (F (ST) > 0.034 and F (ST) > 0.023 respectively). The Shortgrass/CRP Mosaic and Mixed Grass ecoregions appeared admixed (F (ST) = 0.009). Genetic diversity was similar among ecoregions and N (e) ranged from 142 (95 % CI 99-236) for the Shortgrass/CRP Mosaic to 296 (95 % CI 233-396) in the Mixed Grass Prairie. No recent migration was detected among ecoregions, except asymmetric dispersal from both the Mixed Grass Prairie and to a lesser extent the Sand Sagebrush Prairie north into adjacent Shortgrass/CRP Mosaic (m = 0.207, 95 % CI 0.116-0.298, m = 0.097, 95 % CI 0.010-0.183, respectively). Indices investigating potential hybridization in the Shortgrass/CRP Mosaic revealed that six of the 13 individuals with hybrid phenotypes were significantly admixed suggesting hybridization. Continued monitoring of diversity within and among ecoregions is warranted as are actions promoting genetic connectivity and range expansion.Keywords: Spatial genetic population structure, Genetic diversity, Tympanuchus pallidicinctus, Gene flow, Hybridizatio
Correction to: Cluster identification, selection, and description in Cluster randomized crossover trials: the PREP-IT trials
An amendment to this paper has been published and can be accessed via the original article
Modelling human choices: MADeM and decision‑making
Research supported by FAPESP 2015/50122-0 and DFG-GRTK 1740/2. RP and AR are also part of the Research, Innovation and Dissemination Center for Neuromathematics FAPESP grant (2013/07699-0). RP is supported by a FAPESP scholarship (2013/25667-8). ACR is partially supported by a CNPq fellowship (grant 306251/2014-0)
A systematic review and meta-analysis of the influence of peritoneal dialysis catheter type on complication rate and catheter survival
Peritoneal dialysis (PD) is an effective treatment for end-stage renal disease. There are several configurations of PD catheter design that may impact catheter function, such as the shape of the intraperitoneal segment, the number of cuffs, and the subcutaneous configuration. This review and meta-analysis was carried out to determine whether there is a clinical advantage for one of the catheter types or configurations. Comprehensive searches were conducted in MEDLINE, Embase, and CENTRAL (the Cochrane Library 2012, issue 10). The methodology was in accordance with the Cochrane Handbook for Interventional Systematic Reviews and written based on the PRISMA statement. The initial search yielded 682 hits from which 13 randomized controlled trials were identified. Outcomes of interest were as follows: catheter survival, drainage dysfunction, migration, leakage, exit-site infections, peritonitis, and catheter removal. Comparing straight vs. swan neck and single vs. double-cuffed catheters, no differences were found when results were pooled. Comparison of straight vs. coiled-tip catheters demonstrated that survival was significantly different in favor of straight catheters (hazard ratio 2.05; confidence interval 1.10-3.79, P = 0.02). For surgically inserted catheters, the removal rate and survival at 1 year after insertion were significantly in favor of straight catheters. Our meta-analysis clearly demonstrates benefits for catheters with a straight intraperitoneal segment
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