430 research outputs found
Does Antarctic Krill Employ Body Shrinkage as an Overwintering Strategy?
To determine if Antarctic krill employ body shrinkage as one of its overwintering mechanisms in the field, Euphausia superba and Euphausia crystallorophias were collected during fall and winter in and around Marguerite Bay through US Southern Ocean GLOBEC field programs during fall and winter 2001 and 2002. The relationships between the body length and weight of both krill species were exponentially correlated with no significant differences between the two species (p\u3e0.05). The ratio between eye diameter and body length of individual krill was examined in an expectation that it could be used as an indicator of the body shrinkage as previously suggested by Shin and Nicol (2002). These ratios were significantly different between the two krill species. Especially, E. crystallorophias had bigger eyes than E. superba. In both krill species, eye diameters were highly correlated with body lengths (regression coefficients ≥ 0.70). For E. crystallorophias, no significant differences of the ratio of eye diameter/body length were detected between fall and winter. Even though the ratios for E. superba were seasonally varied, it was not clear whether body shrinkage was an actual and critical overwintering mechanism for the krill population found in this study area. These results suggest that some individuals of E. superba might experience the body shrinkage during a part of their life, but this morphological index alone (eye diameter/body length) may be insufficient to unambiguously separate the shrunk krill from the non-shrunk ones in the field-collected animals
Accidental Releases of Sour Gas From Wells and Collection Pipelines in the Overthrust Belt: Calculating and Assessing Potential Health and Environmental Risks
Parts of the Overthrust Belt of western Wyoming and adjoining areas in Utah and Idaho contain geologic formations with significant accumulations of oil and natural gas. Some of these formations, though, yield gas that is contaminated with toxic hydrogen sulfide. As a consequence, the development of these so-called sour-gas reservoirs requires special safety procedures and technologies in order to prevent accidental releases of gas to the atmosphere that could cause adverse occupational and public health effects. To improve the analysis and assessment of wells and collection pipelines completed on lands leased from the Federal Government, the Minerals Management Service, Onshore Operations, now part of the Bureau of Land Management (BLM), asked Lawrence Livermore National Laboratory to conduct a study to test methods to the analysis of the potential risks associated with the development of sour-gas resources located near Evanston, Wyoming. The process of assessing the health risks of a potential sour-gas release involves estimation of the emission rate of hydrogen sulfide, specification of how the gas is released (e.g., vertically into the atmosphere or horizontally), prediction of downwind concentrations of the gas, analysis of the potential health effects, and finally, review of safety methods required to minimize the potential health risks. The first part of the report includes an analysis of data on the health effects of hydrogen sulfide to determine the nature of its dose-response relationship. Following that review is a study of the different methods of quantifying the emission rate of gas from wells and pipelines. Data on the frequency of accidental releases from those facilities are also analyzed. To assess the health risks of an accidental release from a well under BLM supervision located near Evanston, we collected meteorological data for 1 yr from four stations in that area. Our analysis of a worst-case release scenario (i.e., a gas plume that is near the surface) using those data indicates that the greatest risks of incurring an acute health effect (e.g., unconsciousness, respiratory arrest, pulmonary edema, or death) are located in the northwest sector downwind from the well because of the occurrence of stable atmospheric conditions along with slow winds from the southeast. The risks of an acute health effect in that northwest sector over the 20-yr operation of the well were on the order of 10 -4 to 10 -5 -- similar to the risk of accidental death caused by a natural disaster over the same period
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Reducing Interanalyst Variability in Photovoltaic Degradation Rate Assessments
The economic return on investment of a commercial photovoltaic system depends greatly on its performance over the long term and, hence, its degradation rate. Many methods have been proposed for assessing system degradation rates from outdoor performance data. However, comparing reported values from one analyst and research group to another requires a common baseline of performance; consistency between methods and analysts can be a challenge. An interlaboratory study was conducted involving different volunteer analysts reporting on the same photovoltaic performance data using different methodologies. Initial variability of the reported degradation rates was so high that analysts could not come to a consensus whether a system degraded or not. More consistent values are received when written guidance is provided to each analyst. Further improvements in analyst variance was accomplished by using the free open-source software RdTools, allowing a reduction in variance between analysts by more than two orders of magnitude over the first round, where multiple analysis methods are allowed. This article highlights many pitfalls in conducting 'routine' degradation analysis, and it addresses some of the factors that must be considered when comparing degradation results reported by different analysts or methods
Association of Kawasaki disease with tropospheric wind patterns
The causal agent of Kawasaki disease (KD) remains unknown after more than 40 years of
intensive research. The number of cases continues to rise in many parts of the world
and KD is the most common cause of acquired heart disease in childhood in developed
countries. Analyses of the three major KD epidemics in Japan, major non-epidemic
interannual fluctuations of KD cases in Japan and San Diego, and the seasonal
variation of KD in Japan, Hawaii, and San Diego, reveals a consistent pattern
wherein KD cases are often linked to large-scale wind currents originating in
central Asia and traversing the north Pacific. Results suggest that the
environmental trigger for KD could be wind-borne. Efforts to isolate the causative
agent of KD should focus on the microbiology of aerosols
The Spectroscopy of Plasma Evolution from Astrophysical Radiation Mission
The Spectroscopy of Plasma Evolution from Astrophysical Radiation (or the
Far-ultraviolet Imaging Spectrograph) instruments, flown aboard the STSAT-1
satellite mission, have provided the first large-area spectral mapping of the
cosmic far ultraviolet (FUV, lambda 900-1750 Ang) background. We observe
diffuse radiation from hot (10^4 to 10^6 K) and ionized plasmas, molecular
hydrogen, and dust scattered starlight. These data provide for the
unprecedented detection and discovery of spectral emission from a variety of
interstellar environments, including the general medium, molecular clouds,
supernova remnants, and super-bubbles. We describe the mission and its data,
present an overview of the diffuse FUV sky's appearance and spectrum, and
introduce the scientific findings detailed later in this volume
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