4,905 research outputs found
Mathematics Professional Development that Focuses on Student Achievement: A Parallel Case Example
Data communication between data terminal equipment and the JPL administrative data base management system
Approaches to enabling an installed base of mixed data terminal equipment to access a data base management system designed to work with a specific terminal are discussed. The approach taken by the Jet Propulsion Laboratory is described. Background information on the Jet Propulsion Laboratory (JPL), its organization and a description of the Administrative Data Base Management System is included
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Pseudemys texana
Number of Pages: 2Integrative BiologyGeological Science
Spatial and Temporal Trends of Deer Harvest and Deer-Vehicle Accidents in Ohio
Author Institution: Buckeye Valley High School ; USDA Forest Service, Delaware CountyWhite-tailed deer (Odocoileus virginianus} have been increasing dramatically in the eastern United States, with concomitant increases in impacts resulting from deer browsing and deer-vehicle collisions. In Ohio, the number of deer were estimated at near zero in 1940 to over 450,000 in 1995. We analyzed estimates of deer harvest and deer-vehicle collisions in 1995 for 88 counties in Ohio. These data were also related to county-level spatial data on the length of major highways, urban land, rural land, crop land, forest land, all land, and human population. The objectives of this study were to evaluate the spatial and temporal trends of white-tailed deer across Ohio and to relate these patterns to the formerly mentioned environmental and human variables. For 1995 data, positive relationships existed between the amount of urban land in the county versus the number of deer-vehicle collisions, the amount of forest land in the county versus the number of deer harvested, the human population of a county versus the number of deer-vehicle collisions, and the length of major highways in a county versus the number of deer-vehicle collisions. Negative relationships existed between the amount of crop land in a county versus the number of deer harvested, the amount of crop land versus the number of deer-vehicle collisions, and the amount of urban land versus the number of deer harvested. Nine counties, representing various levels of land-use and human population tendencies, were analyzed for historic trends in deer harvest (1985-1995) and deer-vehicle collisions (1988-1995); in each case, there were substantial rises over the previous decade. Extensions of the resulting regression lines show the possibility for continued increases in deervehicle collisions, especially those with a high human population and forest cover. The dramatic increases in deer populations can be attributed to increasing forest land in the state, more habitat of shrubby land, few predators, mild winters, and the deer's ability to adapt to human-inhabited environments
Dust storms on Mars: Considerations and simulations
Aeolian processes are important in modifying the surface of Mars at present, and appear to have been significant in the geological past. Aeolian activity includes local and global dust storms, the formation of erosional features such as yardangs and depositional features such as sand dunes, and the erosion of rock and soil. As a means of understanding aeolian processes on Mars, an investigation is in progress that includes laboratory simulations, field studies of earth analogs, and interpretation of spacecraft data. This report describes the Martian Surface Wind Tunnel, an experimental facility established at NASA-Ames Research Center, and presents some results of the general investigation. Experiments dealing with wind speeds and other conditions required for the initiation of particle movement on Mars are described and considerations are given to the resulting effectiveness of aeolian erosion
Crystallographic studies of the Escherichia coli quinol-fumarate reductase with inhibitors bound to the quinol-binding site
The quinol-fumarate reductase (QFR) respiratory complex of Escherichia coli is a four-subunit integral-membrane complex that catalyzes the final step of anaerobic respiration when fumarate is the terminal electron acceptor. The membrane-soluble redox-active molecule menaquinol (MQH(2)) transfers electrons to QFR by binding directly to the membrane-spanning region. The crystal structure of QFR contains two quinone species, presumably MQH(2), bound to the transmembrane-spanning region. The binding sites for the two quinone molecules are termed Q(P) and Q(D), indicating their positions proximal Q(P)) or distal (Q(D)) to the site of fumarate reduction in the hydrophilic flavoprotein and iron-sulfur protein subunits. It has not been established whether both of these sites are mechanistically significant. Co-crystallization studies of the E. coli QFR with the known quinol-binding site inhibitors 2-heptyl-4-hydroxyquinoline-N-oxide and 2-[1-(p-chlorophenyl)ethyl] 4,6-dinitrophenol establish that both inhibitors block the binding of MQH(2) at the Q(P) site. In the structures with the inhibitor bound at Q(P), no density is observed at Q(D), which suggests that the occupancy of this site can vary and argues against a structurally obligatory role for quinol binding to Q(D). A comparison of the Q(P) site of the E. coli enzyme with quinone-binding sites in other respiratory enzymes shows that an acidic residue is structurally conserved. This acidic residue, Glu-C29, in the E. coli enzyme may act as a proton shuttle from the quinol during enzyme turnover
Bioprocesses
The application of remote sensing techniques to the study of eutrophication in natural waters and the location and characterization of fronts is considered. The specific problem to be studied is examined along with the feasibility and capabability of remote sensing techniques for each application
Avalanche Dynamics in Wet Granular Materials
We have studied the dynamics of avalanching wet granular media in a rotating
drum apparatus. Quantitative measurements of the flow velocity and the granular
flux during avalanches allow us to characterize novel avalanche types unique to
wet media. We also explore the details of viscoplastic flow (observed at the
highest liquid contents) in which there are lasting contacts during flow,
leading to coherence across the entire sample. This coherence leads to a
velocity independent flow depth at high rotation rates and novel robust pattern
formation in the granular surface.Comment: 5 pages, 3 figures in color, REVTeX4, for smaller pdfs see
http://angel.elte.hu/~tegzes/condmat.htm
Intern Self-Care: An Exploratory Study Into Strategy Use and Effectiveness
In this exploratory study, 363 interns were surveyed to assess the frequency of use and effectiveness of self-care strategies used during the internship year. Among the most frequently used strategies were family and friend social support, active problem solving, and humor. The most effective strategies were family and friend social support, seeking pleasurable experiences, and humor. A strong positive relationship was found between total scores for Frequency and Effectiveness subscales, and women reported significantly more use and effectiveness of strategies. Recommendations and resources are provided for interns and internship sites that seek to further understand and encourage intern self-care
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