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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.
331

Foz do Rio Iguaçu como rota alternativa para a reprodução de peixes: jusante das cataratas do Iguaçu / Foz do Iguaçu river as an alternative route for the reproduction of fish : downstream of the Iguassu Falls

Refatti, Alcione 24 February 2016 (has links)
Made available in DSpace on 2017-07-10T14:38:32Z (GMT). No. of bitstreams: 1 Alcione _Refatti.pdf: 576718 bytes, checksum: f91da01987284b0966b64d0b054ca091 (MD5) Previous issue date: 2016-02-24 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Abstract Dispersal patterns of early life stages of fish were evaluated in the Iguaçu River at Iguaçu National Park, Brazil-Argentina. Sampling was conducted in the stretch of 20 km, downstream the Iguaçu Falls to the mouth with Paraná River, over three spawning seasons (2011-2014). Higher densities of eggs drifting occurred especially in December, in 2012-2013. The eggs drift was high through all stretch, however, early stage of development was more abundant nearest downstream Iguaçu Falls, while later stages increased into the mouth. The larvae density drift was low, with predominance of preflexion and flexion stages, especially near the Iguaçu Falls. Our results revealed high drift of buoyant eggs highlighting fish spawning in the rapid and turbulent waters of the Iguaçu River, particularly downstream the Iguaçu Falls, and rainfall could be trigger to spawning. Eggs drift passively by rapid flow towards the mouth (5-11hours), probably most of them hatch in the Paraná River, and the larvae disperse to nursery habitats likely in Paraná River. Additionally, inshore zones along the stretch may provide habitats for the larval development / Padrões de dispersão de peixes na fase inicial da vida foram avaliados no rio Iguaçu no Parque Nacional do Iguaçu, Brasil-Argentina. A amostragem foi realizada no trecho de 20 km, da jusante das Cataratas do Iguaçu até a foz com o rio Paraná, ao longo de três estações de desova (2011-2014). Maiores densidades de ovos ocorreram especialmente em dezembro, em 2012-2013. A deriva de ovos foi elevada por todo trecho, no entanto, os estágios iniciais de desenvolvimento foram mais abundantes no trecho mais próximo à jusante das Cataratas do Iguaçu, enquanto os estágios mais avançados aumentaram na foz com o rio Paraná. A deriva de larvas foi baixa, com predominância dos estágios de pré-flexão e flexão, especialmente próximo das Cataratas do Iguaçu. Nossos resultados revelaram elevada deriva de ovos flutuantes destacando a desova dos peixes nas águas rápidas e turbulentas do rio Iguaçu, particularmente a jusante das Cataratas do Iguaçu, e a precipitação pode ser um gatilho para a desova. Ovos derivam passivamente pelo fluxo rápido em direção a foz (5-11horas), provavelmente a maioria deles eclode no rio Paraná, e as larvas provavelmente dispersam para habitats berçários no rio Paraná. Além disso, as zonas costeiras ao longo do trecho podem fornecer habitats para o desenvolvimento larval.
332

Morphological assessment of paranasal sinuses and teeth in the horse

Liuti, Tiziana January 2018 (has links)
Sinonasal and dental diseases can be a serious disorder in horses due to the persistence of the former and the common extension of the latter to the supporting bones of the skull. The diagnosis of equine sinonasal and dental disease can be challenging due to the complexity of these and adjacent anatomical structures, and therefore the use of advanced imaging, including computed tomography (CT) has greatly increased recently. A major aim of this study was to improve the morphological characterization of the sinuses and cheek teeth in normal horses of different ages. These studies defined the volumes of the 7 different sinus compartments; showed that the volume of the different compartments increase with age; that in contrast to accepted findings, the Triadan 09 alveoli is located in the caudal maxillary sinus (CMS) in 13% of the youngest group and the Triadan 10 alveoli is fully within the rostral maxillary sinus (RMS) in 53% of cases. The infraorbital canal was found to be susceptible to apical infection-related damage in horses < 2 years of age (< 2 y.o.) due to the intimate relationship of this canal and the medial aspect of the maxillary cheek teeth alveoli. The mean positions of the clinical crowns and apices of the maxillary Triadan 11s were 2.48 cm (adjusted 5.2% of head height) and 2.83 cm (adjusted 6.2% of head height) more rostral, respectively in horses >16 y.o. compared to horses < 6 y.o., consistent with rostral dental drift. Measurements of dental drift could provide further objective radiographic guidelines on ageing horses by dental imaging and also help our understanding of the aetiopathogenesis of cheek teeth diastemata. This study also found that the reserve crown length decreased from a mean of 4.7 cm (adjusted 19.7% of head height) in the youngest (< 6y.o.) group of horses to a mean of 2.9 cm (adjusted 10.5% of head height) in the oldest group (>15y.o.), with the 06s and 09s having the shortest reserve crowns. These data are useful reference information for clinicians and radiologists in the diagnosis and treatment of equine sinonasal and dental disease. Morphological characterization of the ventral and dorsal conchal bullae in horses of different age using CT described the age-related difference in sizes of these structures (smaller in younger horses). In the ventral conchal bulla, this reduction in volume was probably related to protrusion of the large dental alveoli in young horses into the nasal cavity and bulla. Bullae linear measurements and volumes were also associated with head size. The anatomical position of both bullae was associated with specific maxillary cheek teeth, thus increasing the diagnostic value of conventional radiography in the investigation of bulla disease and providing landmarks for the surgical treatment of this disorder. Skull shape analyzed with the use of Procrustes statistical analysis showed landmark variability between different age groups and in particular, high landmark variability between young (< 5y.o.) and old (>16y.o.) horses and less landmark variability between adult (6-15y.o.) and old horses. Future studies could investigate changes in the equine skull in relation to genotype to characterize breed-related diseases affecting teeth and sinonasal compartments. In the second part of the study, 32 infected maxillary cheek teeth extracted from clinical cases were evaluated grossly and histologically and these pathological results were compared to the pre-extraction radiographic and CT imaging findings. This study showed a high sensitivity (97%) of CT in detecting changes in teeth affected by apical infection. In the third part of the study, 30 cheek teeth assessed as being abnormal based on oral, radiographic and CT examinations were extracted along with their alveoli from 27 cadaver heads. Gross and histological examination findings from these teeth and alveoli were compared to the pre-extraction imaging findings, again showed high sensitivity (96.4%) of CT in diagnosing cheek teeth apical infection. Additionally, CT showed a high correlation with histology in detecting dental infection related alveolar bone changes including alveolar bone lysis, sclerosis and bone thickening. This aspect of the study was also the second largest pathological study of equine apical infection published to date and thus has also improved our understanding of the pathogenesis of this disorder. In conclusion, CT was shown to be an excellent imaging modality for improving the morphological characterization of the sinuses and teeth in normal horses of different ages, and thus also improving the value of this modality in diagnosis and treatment of disease affecting sinonasal and dental structures. This study also objectively showed the high sensitivity of CT in detecting cheek teeth apical infection in horses as compared to radiography, including by assessment of alveolar bone changes. Overall, the results of this project improve morphological knowledge of the equine skull and teeth and will have direct clinical benefits by improving the diagnosis and thus the treatment of equine sinonasal and dental disease.
333

Detecting rater effects in trend scoring

Abdalla, Widad 01 May 2019 (has links)
Trend scoring is often used in large-scale assessments to monitor for rater drift when the same constructed response items are administered in multiple test administrations. In trend scoring, a set of responses from Time A are rescored by raters at Time B. The purpose of this study is to examine the ability of trend-monitoring statistics to detect rater effects in the context of trend scoring. The present study examines the percent of exact agreement and Cohen’s kappa as interrater agreement measures, and the paired t-test and Stuart’s Q as marginal homogeneity measures. Data that contains specific rater effects is simulated under two frameworks: the generalized partial credit model and the latent-class signal detection theory model. The findings indicate that the percent of exact agreement, the paired t-test, and Stuart’s Q showed high Type I error rates under a rescore design in which half of the rescore papers have a uniform score distribution and the other half have a score distribution proportional to the population papers at Time A. All these Type I errors were reduced when using a rescore design in which all rescore papers have a score distribution proportional to the population papers at Time A. For the second rescore design, results indicate that the ability of the percent of exact agreement, Cohen’s kappa, and the paired t-test in detecting various effects varied across items, sample sizes, and type of rater effect. The only statistic that always detected every level of rater effect across items and frameworks was Stuart’s Q. Although advances have been made in the automated scoring field, the fact is that many testing programs require humans to score constructed response items. Previous research indicates that rater effects are common in constructed response scoring. In testing programs that keep trends in data across time, changes in scoring across time confound the measurement of change in student performance. Therefore, the study of methods to ensure rating consistency across time, such as trend scoring, is important and needed to ensure fairness and validity.
334

Drift of Oligophlebodes sigma and Baetis bicaudatus in a Mountain Stream

Pearson, William Dean 01 May 1970 (has links)
The objective of this study was to clarify the relationships between drift rates, population density, production rates, key environmental factors, and movements of adults within two populations of stream insects (a caddisfly--Oligophlebodes sigma and a mayfly--Baetis bicaudatus). Samples of benthic invertebrates (424 total) were collected every 2 8 days at four stations on Temple Fork of the Logan River, Utah, from October, 1967 to September, 1969. Samples of drift invertebrates (181 total) were collected every 14 days at three stations on Temple Fork during the same period. During summer months (June-September) a day and a night drift sample (681 total) were collected every other day. Drift rates of O. sigma larvae were greatest (5,987 gm/year for O. sigma) when density in the benthos (256 mg/0.1 m2) and production (430 mg/0.1 m2 /year) were greatest. Drift rates were not related positively to density in the benthos over an entire year, but drift rates were correlated positively and significantly (r = .78 and .55 for day drift of O. sigma and B. biaaudatus, respectively) with density during the months of June-September for both O. sigma larvae and B. bicaudatus nymphs. Flow, distance below the spring source of Temple Fork, and densities of competing aquatic insects were other factors of significance in the multiple regression analyses of factors affecting drift rates of the two insects. The 17 independent variables in the multiple regression analyses accounted for 65 percent and 55 percent of the variability in day drift rates of o. sigma and B. bicaudatus, respectively. The adults of O. sigma (but not those of B. bicaudatus) undertook a definite upstream migration estimated at 2-3 km. This flight of adults resulted in a concentration of eggs being laid in the upper reaches of the stream. The advantage of the upstream flight may be that it stores reproductive products in areas where they are relatively safe from the effects of anchor-ice in the winter and floods in late winter and early spring.
335

Foutier Transform Infrared Spectroscopy Instrumentation and Integration with Thermogravimetry

Xiang, Junjie 01 April 2018 (has links)
To discover the potential of IR spectroscopy and explore the details of FTIR instrumentation, a FTIR was built from most basic parts to provide access to every aspect of a IR spectrometer including the hardware and software. The optical system followed the most widely used double-interferometer design. The software control system was developed with LabVIEW to perform data acquisition of the detectors, data processing and controls of the actuators. The FTIR built will be able to provide a full optical IR spectroscopy platform which has a complete control and data acquisition system and can be continuously improved in accuracy and resolution to reach high lab experiment class as the research keep going. The availability of the hardware setup and software source code allows updating of this system for many advanced IR spectroscopy like spatially resolved and time resolved applications. To achieve in-situ material characterization with multiple measurements, some instruments can be modified and integrated with experiments. This thesis provides a practical and useful example of measuring IR spectra and mass of the sample simultaneously during thermal reactions. This instrument was designed and build with a Fourier transform infrared spectrometer (FTIR) and a thermogravimetric analyzer (TGA). Diffuse reflectance Fourier transform (DRIFT) was equipped to a commercial FTIR to acquire the IR spectra. A micro-balance was taken from a TGA was refitted to this system to measure the sample mass. A series of LabVIEW applications was developed for the FTIR control and communication, TGA communication and temperature control. The system was successfully built and tested with calcium oxalate decomposition experiments. The data showed that the instrument has good accuracy and repeatability of both the IR and mass measurement. The analysis of the calcium oxalate data demonstrated good correlation between the IR, mass and temperature parameters.
336

REMOVING VEHICLE SPEED FROM APPARENT WIND VELOCITY

Weiss, Austin M. 01 January 2019 (has links)
Variable-rate technologies for sprayer applications stand to increase efficacy by ensuring the right amount of chemical is applied at the right location. However, external environmental factors such as droplet drift caused by variable ambient condition, are not yet integrated into modern sprayer systems. Real-time wind velocity measurements can be used to control droplet spectra for reducing spray drift by actuating a variable-orifice nozzle. This work aimed to develop data processing methods needed to filter noise and remove vehicle speed from wind velocity measurements collected with an ultrasonic anemometer aboard a moving platform. Using a global navigation satellite system (GNSS), vehicle speed was calculated in the field and subtracted from apparent wind velocity for comparison to static measurements. Experiments under stationary and dynamic sensor deployments were used to develop an algorithm to provide instantaneous local wind velocity and to better understand the local spatiotemporal variability of wind under field conditions.
337

Distribution of sand within selected littoral cells of the Pacific Northwest

Pettit, Don Joseph 01 January 1990 (has links)
Beach sand acts as a buffer to wave energy, protecting the shoreline from erosion. Estimates of the quantity and distribution of beach sand in littoral cells of the PNW are critical to the understanding and prediction of shoreline erosion or accretion. This study was initiated in order to: 1) document the distribution of sand in littoral cells of the Pacific Northwest; 2) determine the factors which have brought about these present distributions; and 3) address the relationship of beach sand distribution to shoreline stability.
338

Pesticide drift in the Midwest: 2010-2016

Ricchio, Jessica L. 01 May 2018 (has links)
Approximately 92% of the land in Iowa, 64% in Indiana, and 27% in Michigan is agricultural farmland. Nearly 77% of farmland in Iowa and Indiana, and 58% of farmland in Michigan, were treated with herbicides in 2012 (USDA). Pesticide drift, or “overspray”, is defined as any off-site movement of pesticide during its application. Exposure to this drift has the potential to damage crops and landscaping, kill aquatic animals, and cause DNA damage, cancer, and allergic wheeze in applicators. The Pesticide Bureau of the Iowa Department of Agricultural and Land Stewardship (IDALS), the Indiana State Chemist (ISC), and the Michigan Department of Agriculture and Rural Development (MDARD) investigate complaints of pesticide misuse, including reports of pesticide drift. Individual narrative reports and case summaries are available, but have not been analyzed to identify contributing factors to prevent field, worker, and community exposures; nor has the community at large been surveyed about reporting practices. The aim of this research was to (1) identify determinants of pesticide drift events in the Midwest, comparing between states; (2) whether differing state policies were associated with drift characteristics and/or reporting of incidents; and (3) determine the proportion of events that occurred due to applicators ignoring pesticide label guidance. This examination will provide guidance when developing policies and prevention efforts used to minimize the hazards associated with pesticide drift. Narrative case reports from IDALS and MDARD, and case summaries from ISC spanning 2010-2016 were analyzed. Narratives and case summaries were converted to trackable data for ease of analysis using Excel. Data analysis includes descriptive statistics on continuous variables (e.g., distance, wind speed), chi-square tests, and t-tests. Analysis includes: crop damage associations with wind speed by chemical; ratio of human exposures across aerial applications, and associations of distance to target crop and reported plant damage. Key state policies were compared and the responses from a survey concerning the reporting of drift incidents was analyzed. The proportion of cases that violated weather and distance recommendations/label directions for the five most common pesticides in each were analyzed. Between 2010 and 2015, Iowa received 471 reported drift cases; between 2011 and 2016 Indiana received 391, and between 2014 and 2016 Michigan received 91 reports. The five most common pesticides analyzed for during drift investigations varied between states, but 2,4-D, glyphosate, and atrazine were common to all states. The method of application, (i.e., aerial or ground), wind speed, and the intended target crop were significantly associated with drift events across all three states. While Iowa was the only state to contain regulatory language concerning drift to bees or livestock, all states still reported 4 to 5% of cases in which pesticides drifted onto animals. Michigan was the only state to suggest the creation and use of a drift management plan and was the only state requiring applicators to inform neighbors of drift. About 30% of confirmed drift cases involved applications within 7.62 meters of desirable vegetation, and about 40% of applications occurred in wind greater than 4.5 m/s. More education, training, and community involvement are suggested interventions to reduce drift cases.
339

Is Rainbow Trout Condition Influenced By Invertebrate-Drift Density?

Filbert, Randall B. 01 May 1991 (has links)
Users of the Instream Flow Incremental Methodology CTFIM) commonly assume that there is a positive linear relationship between available habitat (WUA) and stream fish biomass. However, several studies have shown a lack cf correlation between WUA and biomass. Such poor relationships may occur if other factors limit fish abundance. Food availability is a potentially important factor limiting abundance of stream fishes and can affect blomass by influencing fish condition (individual weight). I collected rainbow trout (Oncorhynchus mykiss) exposed to different levels of invertebrate-drift density to determine if condition was greater where food was more abundant. I also examined whether size-selective predation and gut fullness varied with drift density. Size-selective predation was not related to drift density. However, condition and gut fullness were both significantly correlated with drift density. Furthermore, changes in drift density appeared to have a stronger influence on small-trout condition than large-trout condition. The results of this study and others support the contention that the reliability of the IFIM might be improved if food availability were incorporated into models.
340

DNS and LES of Scalar Transfer Across an Air-water Interface during Inception and Growth of Langmuir Circulation

Hafsi, Amine 17 November 2017 (has links)
Direct numerical simulations (DNS) of an initially quiescent coupled air-water interface driven by an air flow with free stream speed of 5 m/s have been conducted. The DNS solves a scalar advection-diffusion equation for dissolved gas (or scalar) concentration in order to determine the impact of the water-side turbulence on scalar (mass) transfer from the air side to the water side and subsequent vertical transport in the water column. Two simulations are compared: one with a freely deforming interface and a second one with a flat interface. In the first simulation, the deforming interface evolves in the form of gravity-capillary waves generating aqueous Langmuir turbulence characterized by small-scale (centimeter-scale) Langmuir cells (LCs). The second simulation is characterized by pure shear-driven turbulence in the absence of LCs as the interface is intentionally held flat. It is concluded that the Langmuir turbulence serves to enhance vertical transport of the scalar in the water side and in the process increases scalar transfer efficiency relative to the shear-dominated turbulence in the flat interface case. Furthermore, transition to Langmuir turbulence was observed to be accompanied by a spike in scalar flux via molecular diffusion across the interface characterized by an order of magnitude increase. Such episodic flux increases, if linked to gusts and overall unsteadiness in the wind field, are expected to be an important contributor in determining the long-term average of the air-sea gas fluxes. The effectiveness of popular transfer velocity models, namely the small eddy model and the surface divergence model, in predicting this spike is evaluated via the DNS. In addition to LCs, DNS reveals that the water side turbulence is characterized by smaller, shear-driven turbulent eddies at the surface embedded within the LCs. LES with momentum equation augmented with the well-known Craik-Leibovich (C-L) vortex force is used to understand the roles of the wave and shear-driven LCs (i.e. the Langmuir turbulence) and the smaller shear-driven eddies (i.e. the shear turbulence) in determining molecular diffusive scalar flux from the air side to the water side and vertical scalar transport beneath. The C-L force consists of the cross product between the Stokes drift velocity (induced by the interfacial waves) and the flow vorticity. It is observed that Stokes drift shear intensifies the smaller eddies (with respect to purely wind-driven flow, i.e. without wave effects) leading to enhanced diffusive scalar flux at the air-water interface. LC leads to increased vertical scalar transport at depths below the interface and thus greater scalar transfer efficiency.

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