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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
261

Geology of the Willamette Pass area, Cascade Range, Oregon

Woller, Neil M. 01 January 1986 (has links)
The Willamette Pass area is situated at the intersection of two hypothesized structural features, the Western Cascade-High Cascade boundary and the Eugene-Denio lineament. It is of interest due to its designation by the U.S. Department of the Interior as a Known Geothermal Resource Area.
262

The Role of Wood Microsites at Timberline-Alpine Meadow Borders for Conifer Regeneration

Johnson, Adelaide Chapman 07 August 2013 (has links)
This research aimed to determine whether wood microsites ("nurse logs"), which are regeneration sites in Pacific Northwest (PNW) subalpine forests, supported regeneration at timberline-alpine meadow borders. Upward advance of forests and conifer invasion into alpine meadows, which may be occurring in conjunction with climate warming, have gained worldwide attention. Successful alpine meadow seedling regeneration depends on suitable substrate availability, or microsites, for seedling establishment. To better understand factors associated with wood microsite occurrence, mechanisms of wood input were determined and four specific hypotheses were posed to assess: (1) seedling density and seedling survival; (2) growing season length, summer mean growing temperature, and growing degree hours (GDH); (3) active measures of seedling growth; and (4) global wood microsite climate associations. Of four studies, three were conducted in the Cascade Mountains of Washington state along a west - east precipitation gradient and one study, assessed various microsites globally. For Cascades-related research, wood and adjacent soil substrate temperature, moisture, and associated seedling density, survival, stomatal conductance, water potential, and leaf nitrogen were compared by percent transmitted radiation at 4 to 14 study sites. Analysis of variance (ANOVA), t-tests, regressions, and classification and regression trees (CARTs) were used to assess significance of comparisons. Wood microsites, common at 13 of 14 random Cascade sites, had greater seedling densities, greater seedling survival, greater volumetric moisture content (VWC), greater temperature, and greater number of GDH, as compared to adjacent soils. Greater seedling densities were positively associated with VWC (> 12%), conditions most commonly associated with wood substrate presence. For sites having > 25% percent transmitted radiation, positive relationships existed between stomatal conductance and VWC. Globally, high-elevation forests with wood microsites had mean annual precipitation from 86 cm to 320 cm and mean annual temperatures from 1.5°C to 4.7°C. In general, wood microsites facilitated alpine meadow regeneration better than adjacent soils. Management implications included enhanced understanding of factors associated with upward forest advance and wood use for restoration. Globally, wood microsites importance is likely underrepresented. Wood microsites role with warming climate will depend on precipitation pattern, timing, magnitude, and frequency.
263

Mapping current range with respect to abiotic site factors of selected southern oaks (Quercus spp) in Mississippi

Hobbs, Laura Kim 30 April 2011 (has links)
Physical characteristics of a site that plant species inhabit may be useful in deriving the range of the species. Current range maps for tree species of the United States were originally developed by Elbert Little. These range maps were based primarily on observations. The purpose of this study was to update Little’s (Little, 1971) range maps of select southern oak species in Mississippi by calculating the topological, soil, and climatic features of sites using a Geographic Information System (GIS) to analyze environmental variables associated with species distributions. Data collected from databases were input into ArcMap and site data extracted using Hawth’s Analyst Tools. Stepwise logistic regression performed with site variables yielded the parameters used in predictive models to generate probability maps for each species across Mississippi. These probability maps demonstrate the potential to efficiently manage forests by giving a more encompassing view of species occurrence.
264

Application of Concentration, Adsorption and pH in the Precipitation of the Metal Ions of Groups II and III

Cockerell, Leone Doris 06 1900 (has links)
In this thesis, the process involved in the precipitations and separations of the metal of Group II and Group III studied. Suggestions have also been offered whereby students can make an analysis without loosing metals in the initial precepitation.
265

The Long Term Effects of Short-Wave Diathermy and Long-Duration Static Stretch on Hamstring Flexibility

Graham, Daniel Joseph 01 December 2004 (has links) (PDF)
Objective: To compare changes in hamstring flexibility from treatments of pulsed short- wave diathermy and prolonged stretch versus sham diathermy and prolonged stretch and control and to observe how long those changes last. Background: Heat and stretch techniques have been touted for years. To date, the effect of short-wave diathermy and hamstring stretching has not been thoroughly studied. Because diathermy heats a large area and penetrates deep into the muscle, use of this device prior to or during hamstring stretching may increase flexibility and these gains may last longer. Study Design: A randomized, counterbalanced 3x2x6 repeated measures design. The 3 independent variables were day, pretest/posttest, and treatment mode. Treatment mode had 3 levels: diathermy and stretch, sham diathermy and stretch, and control. The dependent variable was the change in knee extension range of motion (ROM). Methods and Measures: Thirty college-age students with tight hamstrings (inability to achieve >160° knee extension at 90° hip flexion) participated. Subjects were assigned to 1 of 3 groups, (diathermy and stretch; sham diathermy and stretch; control). Range of motion was recorded before and after each treatment every other day for 2 weeks. Additional ROM measures were taken on days 15, 22, 29, and 36. A straight-leg raise stretch was performed using a mechanical apparatus. Subjects in the diathermy and stretch group received 10 minutes of diathermy (distal hamstrings), 5 minutes of diathermy and stretch, followed by 5 minutes of stretching only. Subjects in the sham diathermy and stretch group followed the same protocol, except the diathermy unit was turned off. Subjects in the control group lay on the table for 20 minutes. Data were analyzed using an ANOVA, an ANCOVA, and post hoc t-tests. Results: Least Squares (LS) Mean (± Pooled SE) increases in knee extension after 6 treatments were: 11.3 ± 1.2° for the diathermy and stretch group; 10.0 ± 1.2° for the sham diathermy and stretch group; and 3.2 ± 1.2° for the control group. At Day 15, 3 days after the last treatment, the diathermy and stretch group lost 6.9 ± 0.8°; the sham diathermy and stretch group lost 6.6 ± 0.8°; and the control group changed 1.6 ± 0.8°. At Day 22 the diathermy and stretch group had lost 7.4 ± 0.8°; the sham diathermy and stretch group lost 6.8 ± 0.8°; and the control group changed 1.7 ± 0.8° from the last treatment. At Day 29 the diathermy and stretch group had lost 8.2 ± 0.9°; the sham diathermy and stretch group lost 7.1 ± 0.9°; and the control group changed 1.7 ± 0.8° from the last treatment. At Day 36 the diathermy and stretch group had lost 8.3 ± 0.8°; the sham diathermy and stretch group lost 7.4 ± 0.8°; and the control group changed 2.1 ± 0.8° from the last treatment. Conclusion: These results indicate that hamstring flexibility can be improved when long-duration or prolonged stretching is used and that those improvements will slowly diminish over several weeks. Clinicians should consider the use of long-duration stretch to help patients with tight hamstrings increase flexibility and maintain those gains over time.
266

Long Range Surface Plasmon Waveguides for Electrochemical Detection

Hirbodvash, Zohreh 04 November 2022 (has links)
An electrochemical detection method based on long range surface plasmon waveguides is proposed and demonstrated in this integrated article thesis. This dissertation uses CYTOP gold (Au) waveguides supporting long range surface plasmon polaritons (LRSPPs) in conjunction with grating couplers as well as Au waveguides embedded on a one-dimensional photonic crystal (1DPC) supporting Bloch LRSPPs integrated grating couplers. Grating couplers for Au stripe waveguides embedded in Cytop are demonstrated and analyzed. Grating couplers are used in a broadside coupling scheme where a laser beam incident on a stripe of Au on Cytop. The use of gratings for excitation of LRSPPs simplifies optical alignment and does not require high-quality input and output edge facets. Over a broad operating wavelength range, optical experiments are performed to demonstrate coupling loss and determine the efficiency of grating coupling using both a cleaved bow-tie PM fiber and a lensed PM fiber. The coupling loss and grating coupling efficiency of both types of fibers are also calculated numerically. Fluoropolymers with refractive indices close to water, such as CYTOP, are widely used to make waveguide biosensors today. Due to its low glass transition temperature, CYTOP presents limitations to fabrication processes. A truncated 1D photonic crystal may replace a low-index polymer cladding such as CYTOP to support Bloch LRSPPs within the bandgap of the 1DPC over limited wavenumbers and wavelength range. As a result of the high sensitivity of Au stripe Bloch LRSPP waveguide biosensors and their compatibility with high levels of integration, microelectrode systems that can be integrated with such optical biosensors are examined. A chip bearing a Au LRSPP waveguide that can also function as a working electrode (WE), a Pt counter electrode (CE), and Pt/Cu electrical contact pads, is used to demonstrate the electrochemical performance of LRSPPs waveguides. The cyclic voltammetry measurements were performed at different scan rates and concentrations of potassium ferricyanide as the redox species on Au LRSPPs waveguides. By fitting our experimental data to the Randles-Sevcik equation, we find the diffusion coefficient of potassium ferricyanide. The results from CV measurements obtained from chips are compared with commercial macroscopic electrodes. The CV measurements are also compared with theoretical results computed using the Butler-Volmer equation to determine the rate constant of the redox species at zero potential. A waveguide containing a stripe of Au that propagates infrared surface plasmon polaritons (SPPs), acting simultaneously as an electrode in a three-electrode electrochemical cell is also examined. Under SPP excitation, cyclic voltammetry was measured as a function of incident optical power and wavelength (1350 nm). In oxidation and reduction reactions, energetic electrons are separated from energetic holes. Under SPP excitation, redox current densities increase by 10×. With the SPP power, the oxidation, reduction, and equilibrium potentials drop by as much as 2× and separate in correlation with the photon energy. According to electrochemical impedance spectroscopy, charge transfer resistance dropped by almost 2× under SPP excitation. During SPP excitation, the temperature of the working electrode is monitored in situ and independent control experiments are performed to isolate thermal effects. Measurements of chronoamperometry with SPPs modulated at 600 Hz yield a rapid current response modulated at the same frequency, ruling out thermally enhanced mass transport. The observation is attributed to the opening of optically controlled non-equilibrium redox channels associated with the energetic carrier transfer to the redox species. During CV and chronoamperometry measurements, convolutional voltammetry is performed by monitoring the SPP output power versus the applied voltage. Using both experimental and theoretical methods, we demonstrate that the SPP output power is proportional to the electrochemical current convolution. A SPP voltammogram confirms that signal changes are mainly caused by differences in refractive index between reduced and oxidized forms of redox species. In addition, we demonstrate that energetic carriers resulted from SPP absorption significantly improved electrochemical sensitivity. As a complementary electrochemical technique, convolutional voltammetry is useful since the signal is related directly to the concentration of electroactive species on the working electrode (WE) and independent of the scan rate. As a probe of electrochemistry taking place in waveguides, surface plasmon polaritons (SPPs) propagating along one are sensitive. In such a waveguide, the optical output power is proportional to the time convolution of the electrochemical current density, eliminating the need to calculate the latter a posteriori via numerical integration. It is demonstrated that a waveguide WE provide an optical response that can be experimentally validated by chronoamperometry and cyclic voltammetry measurements under SPP excitation for a few potassium ferricyanide (redox species) concentrations in potassium nitrate (electrolyte) and various scan rates. Cyclic voltammetry measurements taken under increasing SPP power produce a regime where SPPs no longer act solely as the probe, but also act as a pump, producing energetic electrons and holes via their absorption in the WE. The energetic carriers enhance (10×) redox current densities as well as the convolution signal measured directly as the optical output power over time.
267

Musculo-skeletal geometry and the control of single degree of freedom elbow movements

Gribble, Paul L. January 1995 (has links)
No description available.
268

Feral hogs in central Mississippi:home range, habitat use, and survival

Hayes, Robert Clay 05 May 2007 (has links)
I examined home range, habitat use, and survival of 29 feral hogs in central Mississippi using radio telemetry. During the dry season (1 April - 31 October 2005), densely-vegetated habitats were very important in home range placement (2nd-order selection) with selection favoring seasonallylooded old fields, followed by old fields and managed openings. During the wet season (1 November 2005 - 31 March 2006), old fields were still preferred followed by agricultural fields, but flooded old fields were not preferred. For habitat selection within the home range (3rd-order selection), hogs preferred old fields and managed openings during the dry season. All habitats were used randomly within home ranges during the wet season. Dry and wet season survival rates were 80.8% and 41.4%, respectively. Hunting was the major cause of mortality (80 ? 100%). Seasonal differences in habitat selection may have been caused by flooding of preferred habitats, food availability and hunting.
269

A COOPERATIVE INQUIRY INVESTIGATION OF TRANSPORT NURSES’ DECISION MAKING AND EXPERTISE

Reimer, Andrew P. 06 July 2010 (has links)
No description available.
270

Absolute continuity and on the range of a vector measure

De Kock, Mienie 15 July 2008 (has links)
No description available.

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