1,096 research outputs found
Influence of water temperature on the efficacy of diquat and endothall versus curlyleaf pondweed
determine the impact of water temperature on the efficacy
of the contact herbicides diquat (6,7-dihydrodipyrido [1,2-
α:2â,1â-c] pyrazinediium ion) and endothall (7-oxabicyclo
[2.2.1] heptane-2,3-dicarboxylic acid) for control of the exotic
nuisance species curlyleaf pondweed (Potamogeton crispus L.)
across a range of water temperatures
Spacelab system analysis: A study of the Marshall Avionics System Testbed (MAST)
An analysis of the Marshall Avionics Systems Testbed (MAST) communications requirements is presented. The average offered load for typical nodes is estimated. Suitable local area networks are determined
Spacelab system analysis: A study of communications systems for advanced launch systems
An analysis of the required performance of internal avionics data bases for future launch vehicles is presented. Suitable local area networks that can service these requirements are determined
YIG Oscillators: Is a Planar Geometry Better?
Two yttrium-iron-garnet (YIG) oscillator technologies are
comparerk the more mature YIG sphere oscillator technology which is
based on the uniform (resonant) precession of the electron spins in a smafl
sphere of YIG, and the new planar YIG technology which utilizes the
propagation of magnetostatic waves in an epitaxiaf film of YIG. The YIG
sphere technology has been used for microwave oscillators for more than
25 years, but has two significant areas of difficulty in applications the
alignment of the YIG sphere in the magnetic bias field coupfbrg cavity
requires great precision and the gain element requires a negative resistance
element to sustain oscillation. The MSW technology is much newer and
less well understood, but the resonator elements are fabricated using a
50- pm line width planar technology making it assappealhg candidate. Both
technologies are reviewed herein with regard to resonant element theory,
temperature, and noise characteristics. New data and theory are presented
on MSW resonator optimization
Relative Energy Requirements for an Erythemal Response of Skin to Monochromatic Wave Lengths of Ultraviolet Present in the Solar Spectrum**From the Departments of Dermatology and Pathology, Baylor University College of Medicine, Houston, Texas.
Perceptions of 24/7 Inâhouse Attending Coverage on Fellow Education and Autonomy in a Pediatric Cardiothoracic Intensive Care Unit
BackgroundThe 24/7 inâhouse attending coverage is emerging as the standard of care in intensive care units. Implementation costs, workforce feasibility, and patient outcomes resulting from changes in physician staffing are widely debated topics. Understanding the impact of staffing models on the learning environment for medical trainees and faculty is equally warranted, particularly with respect to trainee education and autonomy.ObjectiveThis study aims to elicit the perceptions of pediatric cardiology fellows and attendings toward 24/7 inâhouse attending coverage and its effect on fellow education and autonomy.MethodsWe surveyed pediatric cardiology fellows and attendings practicing in the pediatric cardiothoracic intensive care unit (PCTU) of a large, universityâaffiliated medical center, using structured Likert response items and openâended questions, prior to and following the transition to 24/7 inâhouse attending coverage.ResultsAll (100%) trainees and faculty completed all surveys. Both prior to and following transition to 24/7 inâhouse attending coverage, all fellows, and the majority of attendings agreed that the overnight call experience benefited fellow education. At baseline, trainees identified limited circumstances in which onâsite attending coverage would be critical. Preimplementation concerns that 24/7 inâhouse attending coverage would negatively affect the education of fellows were not reflected following actual implementation of the new staffing policy. However, based upon openâended questions, fellow autonomy was affected by the new paradigm, with fellows and attendings reporting decreased âappropriatenessâ of autonomy after implementation.ConclusionsOur prospective study, showing initial concerns about limiting the learning environment in transitioning to 24/7 inâhouse attending coverage did not result in diminished perceptions of the educational experience for our fellows but revealed an expected decrease in fellow autonomy. The study indirectly facilitated open discussions about methods to preserve fellow education and warranted autonomy in our PCTU; however, continued efforts are needed to achieve the optimal balance between supervised training and the transition to autonomous practice.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/111990/1/chd12261.pd
Enhanced diapycnal diffusivity in intrusive regions of the Drake Passage
Author Posting. © American Meteorological Society, 2016. This article is posted here by permission of American Meteorological Society for personal use, not for redistribution. The definitive version was published in Journal of Physical Oceanography 46 (2016): 1309-1321, doi:10.1175/JPO-D-15-0068.1.Direct measurements of oceanic turbulent parameters were taken upstream of and across Drake Passage, in the region of the Subantarctic and Polar Fronts. Values of turbulent kinetic energy dissipation rate Δ estimated by microstructure are up to two orders of magnitude lower than previously published estimates in the upper 1000 m. Turbulence levels in Drake Passage are systematically higher than values upstream, regardless of season. The dissipation of thermal variance Ï is enhanced at middepth throughout the surveys, with the highest values found in northern Drake Passage, where water mass variability is the most pronounced. Using the density ratio, evidence for double-diffusive instability is presented. Subject to double-diffusive physics, the estimates of diffusivity using the OsbornâCox method are larger than ensemble statistics based on Δ and the buoyancy frequency.This work was supported by grants from the U.S. National Science Foundation.2016-10-0
Cigarette Smoke Initiates Oxidative Stress-Induced Cellular Phenotypic Modulation Leading to Cerebral Aneurysm Pathogenesis.
OBJECTIVE: Cigarette smoke exposure (CSE) is a risk factor for cerebral aneurysm (CA) formation, but the molecular mechanisms are unclear. Although CSE is known to contribute to excess reactive oxygen species generation, the role of oxidative stress on vascular smooth muscle cell (VSMC) phenotypic modulation and pathogenesis of CAs is unknown. The goal of this study was to investigate whether CSE activates a NOX (NADPH oxidase)-dependent pathway leading to VSMC phenotypic modulation and CA formation and rupture.
APPROACH AND RESULTS: In cultured cerebral VSMCs, CSE increased expression of NOX1 and reactive oxygen species which preceded upregulation of proinflammatory/matrix remodeling genes (MCP-1, MMPs [matrix metalloproteinase], TNF-α, IL-1ÎČ, NF-ÎșB, KLF4 [Kruppel-like factor 4]) and downregulation of contractile genes (SM-α-actin [smooth muscle α actin], SM-22α [smooth muscle 22α], SM-MHC [smooth muscle myosin heavy chain]) and myocardin. Inhibition of reactive oxygen species production and knockdown of NOX1 with siRNA or antisense decreased CSE-induced upregulation of NOX1 and inflammatory genes and downregulation of VSMC contractile genes and myocardin. p47phox-/- NOX knockout mice, or pretreatment with the NOX inhibitor, apocynin, significantly decreased CA formation and rupture compared with controls. NOX1 protein and mRNA expression were similar in p47phox-/- mice and those pretreated with apocynin but were elevated in unruptured and ruptured CAs. CSE increased CA formation and rupture, which was diminished with apocynin pretreatment. Similarly, NOX1 protein and mRNA and reactive oxygen species were elevated by CSE, and in unruptured and ruptured CAs.
CONCLUSIONS: CSE initiates oxidative stress-induced phenotypic modulation of VSMCs and CA formation and rupture. These molecular changes implicate oxidative stress in the pathogenesis of CAs and may provide a potential target for future therapeutic strategies
Anaerobic Digestion in a Flooded Densified Leachbed
A document discusses the adaptation of a patented biomass-digesting process, denoted sequential batch anaerobic composting (SEBAC), to recycling of wastes aboard a spacecraft. In SEBAC, high-solids-content biomass wastes are converted into methane, carbon dioxide, and compost
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