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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.
181

CHARACTERIZATION AND DISTRIBUTION OF NOVEL NON-LTR RETROELEMENTS DRIVING HIGH TELOMERE RFLP DIVERSITY IN CLONAL LINES OF MAGNAPORTHE ORYZAE

Starnes, John H 01 January 2013 (has links)
The filamentous ascomycete fungus Magnaporthe oryzae is a pathogen of over 50 genera of grasses. Two important diseases it can cause are gray leaf spot in Lolium perenne (perennial ryegrass) and blast in Oryza sativa (rice). The telomeres of M. oryzae isolates causing gray leaf spot are highly variable, and can spontaneously change during fungal culture. In this dissertation, it is shown that a rice-infecting isolate is much more stable at the telomeres than an isolate from gray leaf spot. To determine the molecular basis of telomere instability several gray leaf spot isolates telomeres were cloned, which revealed two non-LTR retrotransposons inserted into the telomere repeats. The elements have been termed Magnaporthe oryzae Telomeric Retrotransposons (MoTeRs). These elements do not have poly-A tails common to many other non-LTR retrotransposons, but instead have telomere like sequences at their 5’ end that allow them to insert into telomeres. Intact copies of MoTeRs were restricted to the telomeres of isolates causing gray leaf spot. Surveys for the presence of these elements in M. oryzae showed they were present in several host-specialized forms including gray leaf spot isolates, but were largely absent in the rice blast isolates. The absence of MoTeRs in rice blast isolates, which are relatively stable by comparison, suggested that the telomere instability in gray leaf spot isolates could be due to MoTeRs. Analyzing spontaneous alterations in telomere restriction fragment profiles of asexual progeny revealed that MoTeRs were involved. Expansion and contraction of MoTeR arrays were observed and account for some telomere restriction profile changes. New telomere formation in asexual progeny followed by MoTeR addition was also observed. Based on this evidence, MoTeRs are largely responsible for the high variability of telomere restriction profiles observed in GLS isolates.
182

Budget-Related Prediction Models in the Business Environment with Special Reference to Spot Price Predictions

Kumar, Akhil 08 1900 (has links)
The purpose of this research is to study and improve decision accuracy in the real world. Spot price prediction of petroleum products, in a budgeting context, is the task chosen to study prediction accuracy. Prediction accuracy of executives in a multinational oil company is examined. The Brunswik Lens Model framework is used to evaluate prediction accuracy. Predictions of the individuals, the composite group (mathematical average of the individuals), the interacting group, and the environmental model were compared. Predictions of the individuals were obtained through a laboratory experiment in which experts were used as subjects. The subjects were required to make spot price predictions for two petroleum products. Eight predictor variables that were actually used by the subjects in real-world predictions were elicited through an interview process. Data for a 15 month period were used to construct 31 cases for each of the two products. Prediction accuracy was evaluated by comparing predictions with the actual spot prices. Predictions of the composite group were obtained by averaging the predictions of the individuals. Interacting group predictions were obtained ex post from the company's records. The study found the interacting group to be the least accurate. The implication of this finding is that even though an interacting group may be desirable for information synthesis, evaluation, or working toward group consensus, it is undesirable if prediction accuracy is critical. The accuracy of the environmental model was found to be the highest. This suggests that apart from random error, misweighting of cues by individuals and groups affects prediction accuracy. Another implication of this study is that the environmental model can also be used as an additional input in the prediction process to improve accuracy.
183

Cumulon: Simplified Matrix-Based Data Analytics in the Cloud

Huang, Botong January 2016 (has links)
<p>Cumulon is a system aimed at simplifying the development and deployment of statistical analysis of big data in public clouds. Cumulon allows users to program in their familiar language of matrices and linear algebra, without worrying about how to map data and computation to specific hardware and cloud software platforms. Given user-specified requirements in terms of time, monetary cost, and risk tolerance, Cumulon automatically makes intelligent decisions on implementation alternatives, execution parameters, as well as hardware provisioning and configuration settings -- such as what type of machines and how many of them to acquire. Cumulon also supports clouds with auction-based markets: it effectively utilizes computing resources whose availability varies according to market conditions, and suggests best bidding strategies for them. Cumulon explores two alternative approaches toward supporting such markets, with different trade-offs between system and optimization complexity. Experimental study is conducted to show the efficiency of Cumulon's execution engine, as well as the optimizer's effectiveness in finding the optimal plan in the vast plan space.</p> / Dissertation
184

Využití umělých neuronových sítí v klasifikaci land cover / Land cover classfication using artificial neural networks

Oubrechtová, Veronika January 2012 (has links)
Land cover classification using artificial neural networks Abstract This Diploma thesis deals with automatic classification of the satellite high spatial resolution image in the field of land cover. The first half of the work contains the theoretical information about remote sensing and classification methods. The biggest attention is given to the artificial neural networks. In practical part of Diploma thesis are these methods used for the classification of SPOT satellite image. Keywords: remote sensing, image classification, artificial neural networks, SPOT
185

Automatizovaná tvorba a kartografická generalizace kótovaných bodů z digitálních modelů reliéfu / Automatic Detection and Cartographic Generalization of Spot Heights from Digital Terrain Models

Polášek, Petr January 2015 (has links)
The aim of this work is to design automatic detection of spot heights from airborne laser scanning data and its generalization. The first part is about the idea of spot height: the importance of spot heights for altimetry representation on maps and suggestions concerning the scatter of spot heights on maps. In the following part, different approaches for terrain critical points extraction (peaks, depressions, passes) from digital terrain models are described as suitable places for spot heights location. Further, we introduce a description of geomorphological characteristics of these points by which is possible to identify its significance and generalize them. In accordance to analysis of Základní mapa ČR and recommendation for spot heights location described in literature we designed own method of automatic generation and generalization spot heights from digital terrain models. This method were implemented and there is a description of the test data and results on the real data DMR 5G of the algorithm in the end of the work. Powered by TCPDF (www.tcpdf.org)
186

Využití meteorologie a historické srovnání povětrnostních podmínek pro jachting a vodní sporty / Application meteorology and historical comparison between weather(meteorological) conditions for yachting and water sports

Hájek, Petr January 2016 (has links)
Title: Application meteorology and historical comparison between weather(meteorological) conditions for yachting and water sports Objectives: To be making maps about windsurfing sports within specific locations. Prove or disprove scientific research about weather conditions changing from 1980 to 2014 years. It's about yachting and water sports at the same locations. Methods: Diploma is descriptive and analytic article. There are methods like research, selections of sources, analysis of information and final synthesis everything knowledge. Results: Description four water ponds for water sports and analytic work with database about weather conditions in the studying locations. Keywords: Meteorology, wind, spot, water sport, yachting.
187

Využití meteorologie a historické srovnání povětrnostních podmínek pro jachting a vodní sporty / Use of meteorology and historical comparisons atmospheric conditions for yachting and water sports

Hájek, Petr January 2015 (has links)
Title: Use of meteorology and historicalcomparisons atmospheric conditions for yachting and water. Objectives: At work I use two basic methods of research. The method of content analysis and interview. Content analysis, I get the information for the theoretical part of the work, using professional sailing and meteorological publications. Furthermore, the method of non-standardized interview, which I took while visiting Mathematics - Physics Faculty at Charles University, Department of Meteorology and Climatology. Here I have discussed his work with Dr.. Joseph Brechler, PhD. Furthermore, with top windsurfing in the Black foothills and Nechranické dam. Methods: At work I used as a basic research methods method of content analysis and interview. Content analysis, I gained information for the theoretical part, the professional sailing and meteorological publications that deal with the issue. Non-standardized interview method I used when visiting Mathematics - Physics Faculty at Charles University, Department of Meteorology and Climatology. Here I discuss my work with Dr.. Joseph Brechler, PhD., Then Ing. Ružbatský in the foothills of the Black and F.Kasík of Nechranice. For wider acquaintance with the issues I was trying to get other sources of information on various internet portals related to...
188

The Effects of Laser and Electron Beam Spot Size in Additive Manufacturing Processes

Francis, Zachary Ryan 01 May 2017 (has links)
In this work, melt pool size in process mapped in power-velocity space for multiple processes and alloys. In the electron beam wire feed and laser powder feed processes, melt pool dimensions are then related to microstructure in the Ti-6Al-4V alloy. In the electron beam wire feed process, work by previous authors that related prior beta grain size to melt pool area is extended and a control scheme is suggested. In the laser powder feed process, in situ thermal imaging is used to monitor melt pool length. Real time melt pool length measurements are used in feedback control to manipulate the resulting microstructure. In laser and electron beam direct metal additive manufacturing, characteristics of the individual melt pool and the resulting final parts are a product of a variety of process parameters. Laser or electron beam spot size is an important input parameter that can affect the size and shape of a melt pool, and has a direct influence on the formation of lack-of-fusion and keyholing porosity. In this work, models are developed to gain a better understanding of the effects of spot size across different alloys and processes. Models are validated through experiments that also span multiple processes and alloys. Methods to expand the usable processing space are demonstrated in the ProX 200 laser powder bed fusion process. In depth knowledge of process parameters can reduce the occurrence of porosity and flaws throughout processing space and allow for the increased use of non-standard parameter sets. Knowledge of the effects of spot size and other process parameters can enable an operator to expand the usable processing space while avoiding the formation of some types of flaws. Based on simulation and experimental results, regions where potential problems may occur are identified and process parameter based solutions are suggested. Methods to expand the usable processing space are demonstrated in the ProX 200 laser powder bed fusion process. In depth knowledge of process parameters can reduce the occurrence of porosity and flaws throughout processing space and allow for the increased use of non-standard parameter sets.
189

Lipid profiles in wheat cultivars resistant and susceptible to tan spot and the effect of disease on the profiles

Kim, Dong Won January 1900 (has links)
Master of Science / Department of Plant Pathology / William W. Bockus / The effects of tan spot on lipid profiles in wheat leaves were quantified by mass spectrometry. Inoculation with Pyrenophora tritici-repentis significantly reduced the amount of many lipids, including the major lipids monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG), in leaves over time. These two lipids accounted for 89% of the mass spectral signal of detected lipids in wheat leaves. Reductions in amounts of lipids were at much higher rates over time for susceptible cultivars compared with resistant cultivars. Furthermore, data show that cultivars resistant to tan spot have different lipid profiles when compared with susceptible cultivars. Resistant cultivars had more MGDG and DGDG than susceptible ones, even in non-inoculated leaves. Using linear models that were fit to data, non-inoculated cultivars with a rating of 1 (highly resistant to tan spot) were calculated to have 66.1% more MGDG and 52.7% more DGDG signal than cultivars with a rating of 9 (highly susceptible). These latter findings are indirect evidence that the amounts of some lipids in wheat leaves may be determining factors in the resistance response of cultivars to tan spot.
190

Resistência de cultivares de caquizeiros à cercosporiose (Pseudocercospora kaki) e o efeito da doença na fisiologia da planta / Resistance of persimmon cultivars to angular leaf spot disease (Pseudocercospora kaki) and the effect of the disease on plant physiology

Antichera, Thaís Silvestre Sanches 07 March 2019 (has links)
O caquizeiro (Diospyros kaki L.) é uma planta caducifólia pertencente à família Ebenaceae, tendo como centro de origem a região central da China. Entre os estados brasileiros, São Paulo é o que apresenta maior produção de caquis com 49.727 t. A cercosporiose (Pseudocercospora kaki), também conhecida como mancha angular, é a principal doença foliar da cultura. Alguns autores atribuem à cercosporiose a queda precoce de folhas, maturação antecipada dos frutos e a redução da produção na safra seguinte. Entretanto, não existem trabalhos com o patossistema P. kaki - D. kaki que deem suporte a essas pressuposições. Diante disso, os objetivos desse trabalho foram comparar a susceptibilidade de quatro cultivares de caquizeiro e avaliar o efeito da cercosporiose na fisiologia da planta. Os experimentos foram conduzidos em condições naturais de campo, com as cultivares Fuyu, Rama Forte, Taubaté e Giombo, por serem as mais cultivadas no estado de São Paulo. Nos experimentos desenvolvidos buscou-se conhecer o grau de resistência das quatro cultivares à cercosporiose, avaliando a incidência, severidade e queda de folhas ao longo de dois ciclos de cultivo, assim como avaliar o controle químico na redução da doença em cvs. Taubaté e Rama Forte e, consequentemente, no acúmulo de reservas na raiz e na qualidade dos frutos colhidos. Foram avaliadas também os danos na fotossíntese em folhas das quatro cultivares com diferentes intensidades de cercosporiose. Como resultados pode-se constatar, que a cv. Fuyu é a mais susceptível à cercosporiose, seguida com resistência média \'Giombo\' e \'Rama Forte\' e com maior resistência a cv. Taubaté. A intensidade da cercosporiose, para severidades da doença de até 7% não influencia na queda de folhas. O controle químico reduziu a intensidade de doença nas cvs. Taubaté e Rama Forte, entretanto, entre as intensidades de cercosporiose avaliadas em plantas tratadas e não tratadas, não há redução no acúmulo de reservas no sistema radicular, assim como na qualidade físico-química dos frutos colhidos. Mesmo a cercosporiose afetando a fotossíntese, no processo fotoquímico, tanto na área lesionada como na área adjacente à lesão, a intensidade da doença observada no campo não foi suficiente para causar redução da produção à cultura. / The persimmon (Diospyros kaki L.) is a deciduous plant of the botanical family Ebenaceae, native to central China. Among the Brazilian states, São Paulo has the highest production of persimmon with 49,727 ton/year. The angular leaf spot of persimmon (Pseudocercospora kaki), also known as cercosporiosis, is the main leaf disease of the crop. Some authors attribute to the cercosporiosis the premature defoliation, early maturation of the fruits and the reduction of the yield in the next crop cycle. However, there are no previous studies with the Pseudocercospora kaki pathosystem that support these hypotheses. Therefore, the objectives of this study were to compare the susceptibility of four persimmon cultivars and evaluate the effect of angular leaf spot on plant physiology. A field experiment was conducted with Fuyu, Rama Forte, Taubaté and Giombo cultivars, the four most cultivated in the state of São Paulo. The degree of resistance to cercosporiosis was determined by the incidence and severity of the disease and by defoliation of the plants in two crop cycles. Chemical spraying for the disease reduction was also evaluated in cvs. Taubaté and Rama Forte. The reduction of the carbohydrate reserve accumulation in the roots and the quality of the fruits harvested were tested. The photosynthesis reduction was also evaluated in leaves of the four cultivars with different intensities of cercosporiosis. The Fuyu cultivar was the most susceptible to cercosporiosis, followed by moderate resistance of \'Giombo\' and \'Rama Forte\' and high resistance of cv. Taubaté. The intensity of cercosporiosis, for disease severity up to 7% does not influence leaf drop. Though the chemical control reduced the disease intensity in cvs. Taubaté and Rama Forte, treated and untreated plants showed no differences in the reserves accumulation in the roots, as well as in the physicochemical quality of the harvested fruits. Even though cercosporiosis affects photosynthesis in the photochemical process on both the necrotic and remaining green leaf area, the intensity of the disease observed in the field was not enough to cause yield reduction to the culture.

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