40,323 research outputs found
Spin-dependent recombination in Czochralski silicon containing oxide precipitates
Electrically detected magnetic resonance is used to identify recombination
centers in a set of Czochralski grown silicon samples processed to contain
strained oxide precipitates with a wide range of densities (~ 1e9 cm-3 to ~
7e10 cm-3). Measurements reveal that photo-excited charge carriers recombine
through Pb0 and Pb1 dangling bonds and comparison to precipitate-free material
indicates that these are present at both the sample surface and the oxide
precipitates. The electronic recombination rates vary approximately linearly
with precipitate density. Additional resonance lines arising from iron-boron
and interstitial iron are observed and discussed. Our observations are
inconsistent with bolometric heating and interpreted in terms of spin-dependent
recombination. Electrically detected magnetic resonance is thus a very powerful
and sensitive spectroscopic technique to selectively probe recombination
centers in modern photovoltaic device materials.Comment: 8 pages, 8 figure
Prosomal-width-to-weight relationships in American horseshoe crabs (Limulus polyphemus): examining conversion factors used to estimate landings
Horseshoe crabs (Limulus polyphemus) are valued by many
stakeholders, including the commercial fishing industry, biomedical companies, and environmental interest groups. We designed a study to test the accuracy of the conversion factors that were used by NOAA Fisheries and state agencies to estimate horseshoe crab landings before mandatory
reporting that began in 1998. Our results indicate that the NOAA Fisheries conversion factor consistently overestimates the weight of male horseshoe crabs, particularly those from New England populations. Because of the inaccuracy of this and other conversion factors, states are now mandated to report the number (not biomass) and sex of landed horseshoe
crabs. However, accurate estimates of biomass are still necessary for use in prediction models that are being developed to better manage the horseshoe crab fishery. We recommend that managers use the conversion factors presented in this study to convert current landing data from numbers to biomass of harvested horseshoe crabs
for future assessments
Large Area Crop Inventory Experiment (LACIE). User requirements
There are no author-identified significant results in this report
Research Notes : United States : Evaluation of soybean germplasm for stress tolerance and biological efficiency : To evaluate soybean germplasm for biological efficiency in - Harvest Index
Two hundred soybean plant introductions and cultivars in each of maturity groups III, IV, and V were evaluated during the 1983 planting season. Data collection consisted of days from emergence to maturity, final plant height, and oven-dried weights of stems and pod walls and seeds from four plants removed from each plot. Seed yield was determined by clipping off the end 30 cm of each plot and harvesting the remaining 1 m of the three rows. This report is limited to data on seed yield efficiency (SYE) values only
Disclosure of Maternal HIV Status to Children: To Tell or Not To Tell . . . That Is the Question
HIV-infected mothers face the challenging decision of whether to disclose their serostatus to their children. From the perspective of both mother and child, we explored the process of disclosure, providing descriptive information and examining the relationships among disclosure, demographic variables, and child adjustment. Participants were 23 mothers and one of their noninfected children (9 to 16 years of age). Sixty-one percent of mothers disclosed. Consistent with previous research, disclosure was not related to child functioning. However, children sworn to secrecy demonstrated lower social competence and more externalizing problems. Differential disclosure, which occurred in one-third of the families, was associated with higher levels of depressive and anxiety symptoms. Finally, knowing more than mothers had themselves disclosed was related to child maladjustment across multiple domains. Clinical implications and the need for future research are considered
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Social interaction contexts bias the perceived expressions of interactants
The present study sought to determine whether contextual information available when viewing social interactions from third-person perspectives, may influence observers’ perception of the interactants’ facial emotion. Observers judged whether the expression of a target face was happy or fearful, in the presence of a happy, aggressive or neutral interactant. In two experiments, the same target expressions were judged to be happier when presented in the context of a happy interactant, than when interacting with a neutral or aggressive partner. We failed to show that the target expression was judged as more fearful when interacting with an aggressive partner. Importantly, observers’ perception of the target expression was not modulated by the emotion of the context interactant when the interactants were presented back-to-back, suggesting that the bias depends on the presence of an intact interaction arrangement. These results provide valuable insight into how social contextual effects shape our perception of facial emotion
Limits on cosmological variation of quark masses and strong interaction
We discuss limits on variation of . The results are
obtained by studying -interaction during Big Bang, Oklo natural
nuclear reactor data and limits on variation of the proton -factor from
quasar absorpion spectra.Comment: 5 pages, RevTe
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