12,311 research outputs found
Accuracy assessment, using stratified plurality sampling, of portions of a LANDSAT classification of the Arctic National Wildlife Refuge Coastal Plain
An application of a classification accuracy assessment procedure is described for a vegetation and land cover map prepared by digital image processing of LANDSAT multispectral scanner data. A statistical sampling procedure called Stratified Plurality Sampling was used to assess the accuracy of portions of a map of the Arctic National Wildlife Refuge coastal plain. Results are tabulated as percent correct classification overall as well as per category with associated confidence intervals. Although values of percent correct were disappointingly low for most categories, the study was useful in highlighting sources of classification error and demonstrating shortcomings of the plurality sampling method
Analysis of X-ray and EUV spectra of solar active regions
Data acquired by two flights of an array of six Bragg crystal spectrometers on an Aerobee rocket to obtain high spatial and spectral resolution observations of various coronal features at soft X-ray wavelengths (9-23A) were analyzed. The various aspects of the analysis of the X-ray data are described. These observations were coordinated with observations from the experiments on the Apollo Telescope Mount and the various data sets were related to one another. The Appendices contain the published results, abstracts of papers, computer code descriptions and preprints of papers, all produced as a result of this research project
Biochemical processes in sagebrush ecosystems: Interactions with terrain
The objectives of a biogeochemical study of sagebrush ecosystems in Wyoming and their interactions with terrain are as follows: to describe the vegetational pattern on the landscape and elucidate controlling variables, to measure the soil properties and chemical cycling properties associated with the vegetation units, to associate soil properties with vegetation properties as measured on the ground, to develop remote sensing capabilities for vegetation and surface characteristics of the sagebrush landscape, to develop a system of sensing snow cover and indexing seasonal soil to moisture; and to develop relationships between temporal Thematic Mapper (TM) data and vegetation phenological state
Source population synthesis and the Galactic diffuse gamma-ray emission
Population synthesis is used to study the contribution from undetected
sources to the Galactic ridge emission measured by EGRET. Synthesized source
counts are compared with the 3rd EGRET catalogue at low and high latitudes. For
pulsar-like populations, 5-10% of the emission >100 MeV comes from sources
below the EGRET threshold. A steeper luminosity function can increase this to
20% without violating EGRET source statistics. Less luminous populations can
produce much higher values without being detected. Since the unresolved source
spectrum is different from the interstellar spectrum, it could provide an
explanation of the observed MeV and GeV excesses above the predictions, and we
give an explicit example of how this could work.Comment: Astrophysics and Space Science, in press. (Proceedings of Conference
'The multi-messenger approach to high-energy gamma-ray sources', Barcelona,
2006). Minor changes for accepted version, updated reference
Parameterization of the Angular Distribution of Gamma Rays Produced by p-p Interaction in Astronomical Environment
We present the angular distribution of gamma rays produced by proton-proton
interactions in parameterized formulae to facilitate calculations in
astrophysical environments. The parameterization is derived from Monte Carlo
simulations of the up-to-date proton-proton interaction model by Kamae et al.
(2005) and its extension by Kamae et al. (2006). This model includes the
logarithmically rising inelastic cross section, the diffraction dissociation
process and Feynman scaling violation. The extension adds two baryon resonance
contributions: one representing the Delta(1232) and the other representing
multiple resonances around 1600 MeV/c^2. We demonstrate the use of the formulae
by calculating the predicted gamma-ray spectrum for two different cases: the
first is a pencil beam of protons following a power law and the second is a
fanned proton jet with a Gaussian intensity profile impinging on the
surrounding material. In both cases we find that the predicted gamma-ray
spectrum to be dependent on the viewing angle.Comment: 8 pages, 7 figures, figure 7 updated, accepted for publication in
ApJ, text updated to match changes by the editor, two refs updated from
preprints to full journal
Assessing Undergraduate Nursing Students\u27 Knowledge, Attitudes and Cultural Competence in Caring for LGBT Patients
Lesbian, gay, bisexual, and transgender (LGBT) patients experience barriers to health care that include fear of discrimination and limited access to providers knowledgeable about and sensitive to the LGBT population and their specific health needs. This study examined the effectiveness of an educational intervention conducted at Illinois Wesleyan University designed to improve knowledge level and attitudes of nursing students toward LGBT patient care. The educational intervention focused on key terminology, health disparities, medical needs of transgender patients and culturally sensitive communication skills necessary for competent LGBT patient care. Knowledge level and attitudes were evaluated before and after the educational intervention using a survey based on a modified Attitudes Toward Lesbians and Gay Men Scale, and two assessment tools developed for this study. The results of this study showed both an improvement in attitudes and an increase in knowledge level directly after the educational intervention. Implications of this study support the inclusion of content related to LGBT patient healthcare into undergraduate nursing curricula to enhance knowledge as well as to promote cultural competence and sensitivity
Summer Climatic Moisture Balances for Yukon Xerophytic Grassland Slopes and Their Late-Wisconsinan Counterparts: Are Present-Day Grasslands Beringian Relicts?
Summer climatic moisture balances (precipitation vs. potential evapotranspiration) for topographic slopes favored by present-day xerophytic boreal grasslands (SSW aspects with 61% – 65% gradients) in southwest Yukon were compared to their unglaciated late-Wisconsinan (14 000 – 12 000 cal yr BP) Beringian counterparts. The purpose was to determine whether present-day grasslands are ecologically plausible Beringian relicts or analogues. The Beringian climate was represented by meteorological stations with average July temperatures 4˚C colder than those of present-day grassland areas; all were from Arctic locations. The most commonly occupied grassland slopes received maximum local solar radiation and likely represented the warmest topographic positions in the landscape. Their summer evapotranspiration demands exceeded the 200 mm moisture supply by 189 mm. The same slopes had late-Wisconsinan summer moisture balances of −57 to −101 mm because of colder and shorter growing seasons. Moisture balances for late-Wisconsinan SSW slopes were similar to those of present-day WNW – NW aspects, which do not support grasslands. Differences in moisture deficits indicated present-day xerophytic grasslands were improbable Beringian in situ relicts or analogues. Alternatively, it was hypothesized that present-day Calamagrostis purpurascens communities developed during the Holocene Thermal Maximum (11 000 – 9000 cal yr BP), whereas Hesperostipa comata communities formed less than 3000 years ago after postglacial migration of the species from central North America.Le bilan hydrique climatique pour la saison d’été (précipitations moins évapotranspiration potentielle) des pentes topographiques favorisées par les herbages boréaux xérophytes actuels (aspects SSO avec pentes de 61 % à 65 %) dans le sud-ouest du Yukon a été comparé à celui de leurs homologues béringiens dénués de glace du Wisconsinien tardif (de 14 000 à 12 000 années cal. BP). L’objectif consistait à déterminer si les herbages actuels sont des relictes béringiens écologiquement plausibles ou des analogues. Le climat béringien a été représenté par des stations météorologiques avec des températures moyennes de 4 ˚C plus froides en juillet que celles des zones d’herbages actuelles. Tous les emplacements étaient dans l’Arctique. Les pentes d’herbages les plus couramment occupées recevaient un rayonnement solaire local maximal et représentaient vraisemblablement les positions topographiques les plus chaudes du paysage. Pendant l’été, leurs demandes d’évapotranspiration ont dépassé l’apport d’humidité de 200 mm dans une mesure de 189 mm. Pour les mêmes pentes, le bilan hydrique du Wisconsinien tardif pour la saison d’été s’établissait de - 57 mm à - 101 mm en raison des températures plus froides et des saisons de croissance plus courtes. Le bilan hydrique des pentes SSO du Wisconsinien tardif ressemblait à celui des aspects ONO-NO actuels, qui ne peuvent pas soutenir les herbages. Les différences en matière de déficit hydrique indiquaient que les herbages xérophytiques actuels étaient d’improbables relictes béringiens in situ ou des analogues. Autrement, on a supposé que les communautés actuelles de Calamagrostis purpurascens se sont formées pendant le maximum thermique de l’Holocène (de 11 000 à 9 000 années cal. BP), tandis que les communautés de Hesperostipa comata se sont formées il y a moins de 3 000 ans, après la migration postglaciaire des espèces du centre de l’Amérique du Nord
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