41,069 research outputs found
Evaluate ERTS Imagery for Mapping and Detection of Changes of Snowcover on Land and on Glaciers
ERTS-1 imagery for mapping and detecting changes in snow cover on land and glacier
Effects of Hyperbaric Hypoxia on Some Enzyme Systems in the Mammalian Liver
The metabolic effects of hypobaric hypoxic stress on the mammalian liver were studied. The lactate dehydrogenase (LDH) and succinate dehydrogenase (SDH) activity of mouse liver homogenates were measured after exposure to an equivalent altitude of 36,000 feet and compared to controls kept at zero altitude. After six and twelve hour incubation periods, the altitude exposed samples demonstrated a significantly higher LDH activity than controls. SDH activity remained unchanged from controls after six hours but was significantly lower than controls after a 12 hour exposure to altitude. It is concluded that the changes in enzyme activity reflect a metabolic control mechanism attempting to maintain adequate energy production during periods of exposure to hypobaric hypoxic stress
The Influence of Safety, Efficacy, and Medical Condition Severity on Natural v. Synthetic Drug Preference
Research indicates that there is a preference for natural v. synthetic products, but the influence of this preference on drug choice in the medical domain is largely unknown. We present 5 studies in which participants were asked to consider a hypothetical situation in which they had a medical issue requiring pharmacological therapy. Participants ( N = 1223) were asked to select a natural, plant-derived, or synthetic drug. In studies 1a and 1b, approximately 79% of participants selected the natural v. synthetic drug, even though the safety and efficacy of the drugs were identical. Furthermore, participants rated the natural drug as safer than the synthetic drug, and as that difference increased, the odds of choosing the natural over synthetic drug increased. In studies 2 and 3, approximately 20% of participants selected the natural drug even when they were informed that it was less safe (study 2) or less effective (study 3) than the synthetic drug. Finally, in study 4, approximately 65% of participants chose a natural over synthetic drug regardless of the severity of a specific medical condition (mild v. severe hypertension), and this choice was predicted by perceived safety and efficacy differences. Overall, these data indicate that there is a bias for natural over synthetic drugs. This bias could have implications for drug choice and usage
SIMsim: An End-to-End Simulation of The Space Interferometer Mission
We present the basic elements and first results of an end-to-end simulation
package whose purpose is to test the validity of the Space Interferometer
Mission design. The fundamental simulation time step is one millisecond, with
substructure at 1/8 ms, and the total duration of the simulation is five years.
The end product of a given "wide-angle" astrometry run is an estimated grid
star catalog over the entire sky with an accuracy of about 4 micro-arcseconds.
SIMsim is divided into five separate modules that communicate via data pipes.
The first generates the 'truth' data on the spacecraft structure and laser
metrology. The second module generates uncorrupted fringes for the three SIM
interferometers, based on the current spacecraft orientation, target stars'
positions, etc. The third module reads out the CCD white light fringe data at
specified times, corrupting that and the metrology data with appropriate
errors. The data stream out of this module represents the basic data stream on
the simulated spacecraft. The fourth module performs fringe-fitting tasks on
this data, recovering the total path delay, and the fifth and final module
inverts the entire metrology/delay dataset to ultimately determine the
instantaneous path delay on a fiducial baseline fixed in space. (Pathlength
feed forward is used every few milliseconds to re-position the interferometer
to keep the fringes in the delay window.) The average of all such delays over
an integration time (typically 30 s) is reported as one of several hundred
thousand measured stellar delays over the five-year period, which are then
inverted to produce the simulated catalog.
Future plans include taking into account more sources of error from the SIM
error budget and including narrow angle observations in the observing plan.Comment: 12 pages, 10 figures; in SPIE conference, Interferometry in Space,
Waikoloa, HI, 26-28 August, 200
Treatment approaches for dual diagnosis clients in England
Introduction - Dual diagnosis (DD, co-occurrence of substance use and mental health problems) prevalence data in England are limited to specific regions and reported rates vary widely. Reliable information on actual service provision for dual diagnosis clients has not been collated. Thus a national survey was carried out to estimate dual diagnosis prevalence in treatment populations and describe the service provision available for this client population in drug/alcohol (DAS) and mental health services (MHS). Design - A questionnaire was sent to managers of 706 DAS and 2374 MHS. Overall, 249 (39%) DAS and 493 (23%) MHS participated in the survey. Results - In both DAS and MHS, around 32% of clients were estimated to have dual diagnosis problems. However, fewer than 50% of services reported assessing clients for both problem areas. Regarding specific treatment approaches, most services (DAS: 88%, MHS: 87%) indicated working jointly with other agencies. Significantly fewer services used joint protocols (DAS: 55%, MHS: 48%) or shared care arrangements, including access to external drug/alcohol or mental health teams (DAS: 47%, MHS: 54%). Only 25% of DAS and 17% of MHS employed dual diagnosis specialists. Conclusions - Dual diagnosis clients constitute a substantial proportion of clients in both DAS and MHS in England. Despite recent policy initiatives, joint working approaches tend to remain unstructured
Stable isotope analysis of human hair and nail samples: the effects of storage on samples
When submitting samples for analysis, maintaining sample integrity is essential. Appropriate packaging must be used to prevent damage, contamination or loss of sample. This is particularly important for stable isotope analysis by isotope ratio mass spectrometry as this technique is capable of detecting subtle differences in isotopic composition with great precision. In a novel study, scalp hair and fingernail samples were placed in five different types of packaging, routinely used in forensic laboratories and stored for 6 weeks and 6 months. Samples were subsequently cleaned and submitted for 13C/12C, 15N/14N, 2H/1H and 18O/16O analysis. Results from 13C analysis indicate that type of packaging can cause slight changes in 13C abundance over time. Differences were noted in the 15N isotope signatures of both hair and nail samples after 6-week storage, but not after 6 months. This apparent discrepancy could be a result of the packaging not being properly sealed in the 6 weeks study. Fewer differences were noted when analyzing samples for 2H and 18O abundance
Comparison of different methods for estimating snowcover in forested, mountainous basins using LANDSAT (ERTS) images
Snow-covered areas on LANDSAT (ERTS) images of the Santiam River basin, Oregon, and other basins in Washington were measured using several operators and methods. Seven methods were used: (1) Snowline tracing followed by measurement with planimeter, (2) mean snowline altitudes determined from many locations, (3) estimates in 2.5 x 2.5 km boxes of snow-covered area with reference to snow-free images, (4) single radiance-threshold level for entire basin, (5) radiance-threshold setting locally edited by reference to altitude contours and other images, (6) two-band color-sensitive extraction locally edited as in (5), and (7) digital (spectral) pattern recognition techniques. The seven methods are compared in regard to speed of measurement, precision, the ability to recognize snow in deep shadow or in trees, relative cost, and whether useful supplemental data are produced
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