Techniques of the FLASH Thin Target Experiment

The fluorescence yield in air is reported for wavelength and pressure ranges of interest to ultra-high energy cosmic ray detectors. A 28.5 GeV electron beam was used to excite the fluorescence. Central to the approach was the system calibration, using Rayleigh scattering of a nitrogen laser beam. In atmospheric pressure dry air, at 304 K the yield is 20.8 {+-} 1.6 photons per MeV

Potential for Post-Fire Recovery of Greater Sage-Grouse Habitat

In the western United States, fire has become a significant concern in the management of big sagebrush (Artemisia tridentata Nutt.) ecosystems. This is due to large‐scale increases in cover of the fire‐prone invasive annual cheatgrass (Bromus tectorum L.) and, concurrently, concerns about declining quantity and quality of habitat for Greater Sage‐grouse (Centrocercus urophasianus). The prevailing paradigm is that fire results in a loss of sage‐grouse habitat on timescales relevant to conservation planning (i.e., 1–20 yr), since sagebrush cover can take many more years to recover post‐fire. However, fire can have effects that improve sage‐grouse habitat, including stimulating perennial grass and forb production. The conditions under which fire results in the permanent loss or enhancement of sage‐grouse habitat are not well understood. We used long‐term data from the Utah Division of Wildlife Resources Range Trend Project to assess short‐term (1–4 yr post‐treatment) and long‐term (6–10 yr post‐treatment) effects of fire on vegetation cover at 16 sites relative to sage‐grouse habitat vegetation guidelines. Sagebrush cover remained low post‐fire at sites considered historically unsuitable for sage‐grouse (10%) pre‐fire sagebrush cover, sagebrush cover decreased to10% cover. Post‐fire sagebrush cover was positively related to elevation. Across all sites, perennial grasses and forbs increased in cover to approximately meet the habitat vegetation guidelines for sage‐grouse. Cheatgrass cover did not change in response to fire, and increased perennial grass cover appears to have played an important role in suppressing cheatgrass. Our results indicate that, while fire poses a potential risk for sage‐grouse habitat loss and degradation, burned sites do not necessarily need to be considered permanently altered, especially if they are located at higher elevation, have high sagebrush cover pre‐fire, and are reseeded with perennial grasses and forbs post‐fire. However, our results confirm that fire at more degraded sites, for example, those wit

STRP Screening Sets for the human genome at 5 cM density

BACKGROUND: Short tandem repeat polymorphisms (STRPs) are powerful tools for gene mapping and other applications. A STRP genome scan of 10 cM is usually adequate for mapping single gene disorders. However mapping studies involving genetically complex disorders and especially association (linkage disequilibrium) often require higher STRP density. RESULTS: We report the development of two separate 10 cM human STRP Screening Sets (Sets 12 and 52) which span all chromosomes. When combined, the two Sets contain a total of 782 STRPs, with average STRP spacing of 4.8 cM, average heterozygosity of 0.72, and total sex-average coverage of 3535 cM. The current Sets are comprised almost entirely of STRPs based on tri- and tetranucleotide repeats. We also report correction of primer sequences for many STRPs used in previous Screening Sets. Detailed information for the new Screening Sets is available from our web site: . CONCLUSION: Our new human STRP Screening Sets will improve the quality and cost effectiveness of genotyping for gene mapping and other applications

Radioecological studies related to the BANEBERRY event

On December 18, 1970, at 7:30 a.m., PST, a venting occurred at the Nevada Test Site in conjunction with the Baneberry test. The Lawrence Radiation Laboratory (LRL) Bio-Medical Research Division and the University of Utah responded to this event by activating their jointly operated air-sampling network and by gathering forage, milk, and animal samples. These data are used to calculate the dose to humans from inhalation, submersion, and food-chain contamination; food-chain contamination calculations are limited to the cow-milk pathway, but included bovine inhalation. The question of food-chain contamination is explored under both the actual situation that dairy cows were fed stored feed and under the hypothetical situation that dairy cows were fed fresh feed. Our results show that {sup 131}I was the significant radionuclide emitted by the event and that the strongest dose was received by the thyroid glands of both foraging animals and humans. The integrated concentrations of {sup 131}I were higher in the northern part of Utah; the maximum value of 1100 pCi h m{sup {minus}3} was recorded at Draper (near Salt Lake City). For conservative results, we calculated the dose to a child rather than an adult. For the actual conditions following the venting, we estimate on the basis of measurements of baled hay and or milk that the dose to an infant's thyroid via the cow-milk pathway was between 0.0065 and 0.012 rad at Draper. If cows had been continuously on fresh pasture, we estimate that the dose to the infant thyroid for the same integrated air concentration would have been 1.3 rad for dry deposition and up to 100 rad for wet deposition. 24 refs., 3 figs., 13 tabs

Timberland and woodland resources outside national forests in western Wyoming, 1984 /

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