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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.
191

Stellar masses and laboratory astrophysics

Haddock, D. J. January 1987 (has links)
No description available.
192

Radiative emission from O←3 and HNO←3 in the middle atmosphere

Pemberton, David N. C. January 1993 (has links)
No description available.
193

Within-day and between-day reliability of body composition by air-displacement plethysmography in the bod pod

Sparks, Jada L. January 1999 (has links)
The purpose of this study was to determine the reliability of within-day and between-day measurements of body volume (BV), thoracic gas volume (Vtg), and body fat percentages (%fat) taken in the BOD POD. Fifty subjects (25 men, 25 women) of varying ages (20-81 yrs.), races, and body composition (2.2-51.1% fat) were tested under ideal conditions set forth by the manufacturer at the same time of day (± 3 hours) on three separate days within two weeks. On each day, testing was repeated in succession until three trials were obtained which met the manufacturer's criteria for acceptable BV and Vtg. Repeated measures ANOVA revealed no significant mean differences between the three within-day trials or for the first trial between each of the three days with the exception of between-day BV where day 1 was found to be 260 ml greater than days 2 and 3. Coefficient of variation (SD/mean* 100) and intra-class correlations were determined for each variable both within the three trials of each day and between the first trials of each of the days. For BV, the CV for the 150 cases of within-day measurements was.1 ± .01% while the between-day CV was .4 +.3%. For both within and between day BV, r = .99. The CV and correlations for Vtg was 2.8 ± 2.4% and .99 and 4.1 ± 2.6% and .98 for within-day and between-day measures, respectively. The mean absolute difference between measured Vtg and the predicted value (Vpred) from age, height, and weight was 0.471 ± 0.392 L which would result in body fat estimates that differ by 1.3 ± 0.3%. Estimates of body fat from Vpred were within +2% fat of those derived from measured Vtg values in 80% of the trials. Body fat percentage produced a within-day CV of 2.8 + 4.6% with an r = .99 and a between-day CV of 3.8 ± 5.9% with an r =.99. However, with the exclusion of 3 subjects with body fat <7%, the within-day and between-day CV decreased to 2.0 ± 1.8% and 2.7 ± 2.1%, respectively. The difference between the first two trials of each day was < 2% fat in 93% of the cases, and all 150 cases resulted in fat within + 2% in the three trials. In conclusion, these results support that BOD POD measurements of BV, Vtg, and % fat are reliable both within and between days for a wide range of adults. Also, to obtain the most reliable measurement of % fat in the BP, measuring thoracic gas volume and averaging the values obtained from two trials which agree within + 2 % fat is recommended. / School of Physical Education
194

On the calculation of particle trajectories from sea surface current measurements and their use in satellite sea surface products off the Central California Coast

Spence, Luke J. 12 1900 (has links)
This thesis explores the possibility and feasibility of improving existing satellite measurements of sea surface temperature (SST) by the incorporation of high- frequency (HF) radar-derived surface current data. Water parcels tagged with SST are advected using particle trajectories calculated by integrating surface current velocity data. The SST of these advected water parcels are compared to SST measurements at the final times and locations of the advected water parcels. Different methods of generating surface currents from HF radar measurements are also examined. The Totals current method is a local fitting method which generates surface current measurements by solving a least-squares equation fitting multiple measurements from different radar sites. The Open-boundary Modal Analysis (OMA) method is a global method which fits a series of eigenfunction modes to available radial measurements. These modes are generated by solving two Laplacian eigenvalue problems on the domain with Dirichlet and Neumann boundary conditions, and adding a set of boundary modes to account for flow across open boundaries. Any current field in the domain can be described using a combination of these modes. The two methods are compared for accuracy against an analytic solution to the linear Stommel problem. / NOAA Corps author
195

The binocular interaction of ocular accommodation and vergence

Eadie, Andrew S. January 1993 (has links)
No description available.
196

Free thyroid hormone and sensitive thyrotrophin measurements in the assessment of thyroid status

Gow, Sadie Maxine January 1987 (has links)
No description available.
197

Measuring information gain in the objective force

Baird, Joseph A. 06 1900 (has links)
Approved for public release; distribution is unlimited. / Many researchers are attempting to quantify or understand the value of information, especially for the Army as it enters its transformation. Information can be decomposed into various qualities. Three of these qualities, timeliness, accuracy, and completeness, form the basis for this thesis. This thesis uses a simulation framework developed by the author to analyze the three components of information listed above. The scenario selected is a typical vignette of an Objective Force company-sized element conducting offensive operations against threat elements. Knowledge of the threat was compromised by the presence of decoy elements as well as previously damaged or killed systems (BDA). In this scenario the fires are initiated from standoff ranges. The initial and running assessments of the threat composition are made based on the information provided by sensors on board the unit's organic unmanned aerial vehicles (UAVs). Analysis of the simulation results helps in understanding how components of information quality affect the overall effectiveness of the force as reflected in an efficiency measure. Additionally, critical thresholds for accuracy, completeness, and timeliness of information are pinpointed to inform Objective Force decision makers. / Major, United States Army
198

A comparison of in-situ measurements and satellite remote sensing of underwater visibility

Museler, Erica A. 03 1900 (has links)
Approved for public release; distribution is unlimited. / SeaWiFS data converted to optical properties of the ocean in the form of vertical and horizontal underwater visibility products are compared to in-water diver and optical instrument measurements during the Model Diver Visibility (MoDiV) experiment. Results were collected from 19 to 21 August in the Mississippi Bight region of the United States. The SeaWiFS satellite data was processed with the Automated Processing System (APS), developed by the Naval Research Laboratory (Code 7333). APS converted radiance values into specific parameters studied: the beam attenuation coefficient, the diffuse attenuation coefficient, vertical visibility and horizontal visibility. These values were compared to the AC-9instrument, a-Beta instrument, Secchi disk and the observed visibilities from the divers. The results indicated that the beam attenuation coefficient and the diffuse attenuation coefficient are underestimated as compared to the in-situ measurements. These values then overestimate the vertical and horizontal visibility as compared to the Secchi disk and diver sightings. The visibility products from SeaWiFS should be used on an experimental basis for Naval Operational Planning. It is recommended that the use of in-water diver reports noting variability of SeaWiFS visibility product estimates are necessary for validation and offers feedback to the research and development field for algorithm improvement. / Lieutenant, United States Navy
199

Role of prostaglandins in nociception during ischaemia and reperfusion of the rat's tail

Gelgor, Linda 07 March 2014 (has links)
I have investigated the effects o f both systemic and intracerebroventricular administration o f non-steroidal anti-inflammatory drugs (NSAIDs), o f varying therapeutic potency, on i) nociception during tail ischaemia and ii) hyperalgesia to a noxious thermal stimulus, evident during reperfusion of the receptive field on the tail, in conscious Sprague-Dawley rats. NSAIDs were found to attenuate the hyperalgesia evident during reperfiision o f the tail, whilst having no effect on the escape latency to a noxious ischaemic stimulus or on the tail flick latency in the absence of tail ischaemia. The intracerebroventricular doses required to attenuate reperfiision hyperalgesia were 2-3 orders o f magnitude less than those required by systemic administration for the same drugs. Using mechanical search stimuli, I located neurones in the dorsal horn of the spinal cord of rats with receptive fields in the tail. Neuronal responses to noxious and innocuous mechanical stimulation, as well as to noxious thermal stimulation before ischaemia and during reperfusion after ischaemia, were assessed. Of the population of neurones I examined, only a minority responded to thermal stimulation before ischaemia, and during reperfiision the neurones became more sensitive to mechanical stimuli, but not to noxious thermal stimuli. Furthermore, the neurones exhibited a decreased sensitivity to mechanical stimulation during ischaemia. Application of NSAIDs to the spinal cord did not alter the response properties of the neurones during receptive field ischaemia, but decreased receptive field size and reduced spontaneous and evoked activity during reperfusion of the tail. I have shown that the neurochemical mechanisms underlying nociception during ischaemia and reperfusion of the rat tail are different. While prostaglandins appear to pla] .0 role in mediating nociception during ischaemia, they are mediators of the hyperalgesia and neuronal hypersensitivity evident during receptive field reperfusion.
200

The distribution of aerosol and trace gases in the lower troposphere over South Africa

Burger, Roelof Petrus January 2016 (has links)
A thesis submitted to the Faculty of Science, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. September 2016. / Numerous studies on the sources, transport and fates of criteria air pollutants and greenhouse gases have been done in southern Africa. However, debate on the priority pollutants and areas of concern continue despite a growing national air quality monitoring network. This study attempts a novel approach to characterise sources and ambient air quality over major industrial and urban areas using a single suite of instrumentation to provide information to improve management of air quality. Over 200 hours of data were collected from an airborne platform. Another 5 ground-based campaigns characterised sources and areas out of reach of the aircraft. The central aim of this study is to prioritise sources and areas of concern with regards to air quality management, using a mobile platform. This complements other modelling and spatial assessments and provides in situ validation for many contemporary debates. The specific aims were to characterise major anthropogenic sources; estimate the state of air quality; investigate the vertical distribution of pollutants; and prioritise sources and areas of concern for effective air quality management in South Africa. The research has delivered many original contributions to the body of knowledge of air quality over South Africa. These findings can be divided into spatial and temporal relationships between sources and receptors, characterising source contributions and understanding the contribution of atmospheric emissions. High resolution measurements show that spatial scales of prominent atmospheric plumes are much smaller than current remote sensing estimates.This underscores the difficulty of accurately assessing environments with diverse, clustered sources and complex meteorology through modelling studies and satellite based remote sensing. The current conceptual model of absolute stable layers is biased because of limited data availability where a limited number of levels are reported. At least 60 levels should be reported in soundings to study absolutely stable layers. The inclusion of the standard reporting levels, (850 hPa, 700 hPa, 500 hPa and 300 hPa), further biases the detection of atmospheric stable layers. The number of observed persistent levels change in number and character when these are omitted from the analysis. Numerous vertical profiles further show that the thermodynamic model of stability as the main driver of stratification is oversimplified, especially close to source regions where different pollutants are observed to peak at different levels unrelated to absolutely stable layers. This suggests that the original buoyancy which is governed by the release temperature, exit velocity and height are important drivers for the stratification of pollutants. The overall conclusion is made that a small team with a set of regular instrumentation can prioritise pollutants and areas of concern on a national scale. This method could be valuable for countries with limited resources and infrastructures and could be used in combination with modelling and satellite based remote sensing to assess priorities. The ability to obtain in situ data of a large number of variables over vast areas in a short time may offsets the caveats associated with mobile measurements and a limited sample volume. / LG2017

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