7,211 research outputs found

    On some properties of the water-vapor spectrum and their relations to atmospheric radiation

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    In the present paper we investigate the physical consequences of the fact that the water vapor spectrum in the far infrared consists of a large number of narrow lines. It will be shown that the average width of these lines is much smaller than the intervals which could be resolved with the spectrographs used hitherto. For thick layer of vapor complete absorption is nevertheless reached in most parts of the spectrum. It can be shown that under such circumstances the total absorption is approximately proportional to the air pressure in the absorbing layers and is inversely proportional to the square root of the absolute temperature. There is an additional variation with temperature of a more complex type which cannot yet be quantitatively evaluated from the available measurements, but it is probably not very large

    Further studies of the efficacy of military, commercial and novel skin decontaminants against the chemical warfare agents sulphur mustard, soman and VX

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    Background/Aims: Following an incident involving toxic chemicals, deployment of countermeasures before the arrival of specialised services at the scene may provide a “therapeutic” window in which to mitigate skin absorption. Methods: Five potential candidates (itaconic acid, N,N′-methylenebisacrylamide, 2-trifluoromethylacrylic acid, fuller's earth and Fast-Act®) previously found effective against a simulant (methyl salicylate) were evaluated against a 10 μL droplet of 14C-sulphur mustard (HD), soman (GD) or VX applied to the surface of porcine skin mounted on static skin diffusion cells. Results: All the decontaminants applied to the skin 5 min post exposure achieved a marked reduction in the amount of 14C contaminant remaining within the skin at 24 h. Itaconic acid significantly (p <.05) reduced the amount of 14C-HD, GD and VX remaining in the skin at 24 h. Additionally, 2-trifluoromethylacrylic acid significantly reduced the amount of 14C-HD, whilst fuller's earth significantly reduced the amounts of 14C-HD and VX recovered within the skin at 24 h. Conclusion: All of the products evaluated in this study performed well in reducing the dermal absorption of all the chemical warfare agents tested.Peer reviewe

    The periodic standing-wave approximation: nonlinear scalar fields, adapted coordinates, and the eigenspectral method

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    The periodic standing wave (PSW) method for the binary inspiral of black holes and neutron stars computes exact numerical solutions for periodic standing wave spacetimes and then extracts approximate solutions of the physical problem, with outgoing waves. The method requires solution of a boundary value problem with a mixed (hyperbolic and elliptic) character. We present here a new numerical method for such problems, based on three innovations: (i) a coordinate system adapted to the geometry of the problem, (ii) an expansion in multipole moments of these coordinates and a filtering out of higher moments, and (iii) the replacement of the continuum multipole moments with their analogs for a discrete grid. We illustrate the efficiency and accuracy of this method with nonlinear scalar model problems. Finally, we take advantage of the ability of this method to handle highly nonlinear models to demonstrate that the outgoing approximations extracted from the standing wave solutions are highly accurate even in the presence of strong nonlinearities.Comment: RevTex, 32 pages, 13 figures, 6 table

    Optimization techniques applied to passive measures for in-orbit spacecraft survivability

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    Spacecraft designers have always been concerned about the effects of meteoroid impacts on mission safety. The engineering solution to this problem has generally been to erect a bumper or shield placed outboard from the spacecraft wall to disrupt/deflect the incoming projectiles. Spacecraft designers have a number of tools at their disposal to aid in the design process. These include hypervelocity impact testing, analytic impact predictors, and hydrodynamic codes. Analytic impact predictors generally provide the best quick-look estimate of design tradeoffs. The most complete way to determine the characteristics of an analytic impact predictor is through optimization of the protective structures design problem formulated with the predictor of interest. Space Station Freedom protective structures design insight is provided through the coupling of design/material requirements, hypervelocity impact phenomenology, meteoroid and space debris environment sensitivities, optimization techniques and operations research strategies, and mission scenarios. Major results are presented

    Staircases, dominoes, and the growth rate of 1324-avoiders

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    We establish a lower bound of 10.271 for the growth rate of the permutations avoiding 1324, and an upper bound of 13.5. This is done by first finding the precise growth rate of a subclass whose enumeration is related to West-2-stack-sortable permutations, and then combining copies of this subclass in particular ways

    Estimates of Marine Mammal, Sea Turtle, and Seabird Mortality in the California Drift Gillnet Fishery for Swordfish and Thresher Shark, 1996–2002

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    Estimates of incidental marine mammal, sea turtle, and seabird mortality in the California drift gillnet fishery for broadbill swordfish, Xiphias gladius, and common thresher shark, Alopias vulpinus, are summarized for the 7-year period, 1996 to 2002. Fishery observer coverage was 19% over the period (3,369 days observed/17,649 days fished). An experiment to test the effectiveness of acoustic pingers on reducing marine mammal entanglements in this fishery began in 1996 and resulted in statistically significant reductions in marine mammal bycatch. The most commonly entangled marine mammal species were the short-beaked common dolphin, Delphinus delphis; California sea lion, Zalophus californianus; and northern right whale dolphin, Lissodelphis borealis. Estimated mortality by species (CV and observed mortality in parentheses) from 1996 to 2002 is 861 (0.11, 133) short-beaked common dolphins; 553 (0.16, 103) California sea lions; 151 (0.25, 31) northern right whale dolphins; 150 (0.21, 27) northern elephant seals, Mirounga angustirostris; 54 (0.41, 10) long-beaked common dolphins, Delphinus capensis; 44 (0.53, 6) Dall’s porpoise, Phocoenoides dalli; 19 (0.60, 5) Risso’s dolphins, Grampus griseus; 11 (0.71, 2) gray whales, Eschrichtius robustus; 7 (0.83, 2) sperm whales, Physeter macrocephalus; 7 (0.96, 1) short-finned pilot whales, Globicephala macrorhychus; 12 (1.06, 1) minke whales, Balaenoptera acutorostrata; 5 (1.05, 1) fin whales, Balaenoptera physalus; 11 (0.68, 2) unidentified pinnipeds; 33 (0.52, 4) leatherback turtles, Dermochelys coriacea; 18 (0.57, 3) loggerhead turtles, Caretta caretta; 13 (0.73, 3) northern fulmars, Fulmarus glacialis; and 6 (0.86, 2) unidentified birds

    The market for endogenous trade protection : antidumping and tariff protection in South Africa's period of transition

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    Includes abstract.Includes bibliographical references (leaves 29-32).This paper examines the relationship between tariffs and antidumping (AD) within the political economy of trade protection in South Africa. Using graphs, tables, panel data regressions and an application of the Grossman-Helpman model I build an understanding of the relationship between tariffs and AD. Findings are that AD has increased with the decrease in tariffs. However this relationship is not a clear-cut substitution from one trade remedy to another

    The Admissibility of Wiretap Evidence in the Federal Courts

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    Dream Content Within the Partially Lucid REM Period: A Single Subject Content Analysis

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    Despite ten years of increasing research attention to lucid dreaming, quantitative content analysis is almost nonexistent. Most research describing their content has dealt almost exclusively with those qualities of the dreamer's consciousness that by definition serve to differentiate lucid dreams from their non-lucid counterparts. But aside from obvious differences in self-awareness and cognitive ability, in what ways do lucid and non-lucid dreams differ? While discussing the relevance of findings on lucid dreaming to dreaming in general, Foulkes asked: When you change ordinary dreaming by adding a self which intends and reflects, what else changes alongside this change? This is one way of evaluating the role played by the absence of self [-awareness] in ordinary dreaming, and is perhaps the point at which lucid dreaming data could be most relevant to ordinary dream psychology. However, at present there seems to be no systematic data comparing the REM-monitored lucid versus non-lucid dreams of the same dreamer
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