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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.
51

Nematoides em feijoeiro-comum: ocorrência nos Estados do Paraná e São Paulo, e interação de cultivares com Pratylenchus brachyurus, Meloidogyne incognita e Meloidogyne javanica / Nematodes in common bean: occurence in Paraná and São Paulo state, and interaction of cultivars with Pratylenchus brachyurus, Meloidogyne incognita e Meloidogyne javanica

Mauro Ferreira Bonfim Junior 30 September 2013 (has links)
O feijoeiro-comum (Phaseolus vulgaris L.) é cultivado em vários países ao redor do mundo. O Brasil figura nesse cenário como o segundo maior produtor mundial de grãos secos da cultura, que é a principal fonte de proteína de origem vegetal para o consumo interno. Os nematoides-das-galhas, Meloidogyne incognita e M. javanica, são as principais espécies causadoras da redução de produtividade da cultura. Entretanto, o status hospedeiro das cultivares comerciais atuais ao nematoide das galhas é desconhecido. Da mesma maneira, a distribuição, a resistência de cultivares e os danos de Pratylenchus brachyurus à cultura não foram investigados até o momento. Tendo em vista tal situação, o presente trabalho teve como objetivo determinar quais espécies de nematoides ocorrem em áreas produtoras de feijoeirocomum; verificar a influência de P. brachyurus sobre o crescimento da cultivar Pérola; e o status hospedeiro de cultivares comerciais à P. brachyurus, M. incognita e M. javanica para o possível uso no manejo de áreas infestadas e como fonte de resistência em programas de melhoramento. No levantamento, coletaram-se 69 amostras compostas provenientes de dez cidades nos estados do Paraná e de São Paulo. Os efeitos de diferentes níveis populacionais de P. brachyurus sobre o crescimento de feijoeiro-comum cv. Pérola e sobre parâmetros de resistência [FR=população final (Pf)/população inicial (Pi) e nematoides/g de raiz (Nem./g)] foram avaliados. Trinta e cinco cultivares comerciais de feijoeiro-comum, adaptadas às regiões Centro-Oeste, Sudeste e Sul do Brasil foram avaliadas quanto à sua resistência às três principais espécies encontradas no levantamento, por meio do FR. Classificaram-se as cultivares com FR=1 como suscetíveis. As seguintes espécies foram encontradas nos levantamentos: P. brachyurus, P. crenatus, M. incognita, M. javanica, Rotylenchulus reniformis e Helicotylenchus dihystera. Observou-se redução na massa fresca de raízes (g) da cultivar Pérola, nos tratamentos inoculados com 6,66 e 20 nem./cm³ de solo. Os FR foram maiores nos tratamentos com baixa Pi (0,83 e 2,5 nem./cm³ de solo). Apesar das cultivares terem mostrado FR variado, nenhuma das cultivares apresentou resistência às três espécies estudadas. / Common bean is grown in several countries around the world. Brazil is the second main producing of dry grains, which is the main source of protein for national consumption. The root-knot nematodes, Meloidogyne incognita and M. javanica, are the major species causing yield reduction in that crop. However, the host status of actual cultivars to those rootknot nematodes is unknown. Likewise, the distribution, resistance and damage caused by Pratylenchus brachyurus to the crop were not investigated yet. In view of such situation, the present work aimed survey and identify phytonematodes in common bean fields; verify the effect of P. brachyurus on the growth of the cultivar Pérola; and the host status of actual cultivars to P. brachyurus, M. incognita and M. javanica, in order to enable the management in infested areas, as well as to use like source of resistance in breeding programs. A total of 69 samples from ten cities in Paraná and São Paulo State were surveyed. The effects of different population densities of P. brachyurus on the growth of cultivar Pérola and on parameters of resistance [FR=final population (Pf)/initial population (Pi) and nematodes/g of roots (Nem./g)] were evaluated. Thirty five common bean cultivars, adapted to center-west, southeast and south of Brazil were evaluated for resistance to the three main species found in the survey. The cultivars with FR=1 as susceptible. The following species were found in the surveys: P. brachyurus, P. crenatus, M. incognita, M. javanica, Rotylenchulus reniformis e Helicotylenchus dihystera. Reduction in root fresh weight (g) of cultivar Pérola, in the treatments inoculated with 6.66 and 20 nem./cm³ of soil were observed. The FR was higher in the treatments with low Pi (0.83 and 2.5 nem./cm³ of soil). Despite the cultivars have shown varied FR, resistance for the three nematode species studied was not found in any cultivar.
52

Desempenho agronômico de cultivares de mamona no Rio Grande do Sul

Aires, Rogério Ferreira 28 March 2008 (has links)
Made available in DSpace on 2014-08-20T14:33:05Z (GMT). No. of bitstreams: 1 Dissertacao_ Rogerio_ F_ Aires.pdf: 523607 bytes, checksum: a908349e99f4ee12d83b2ba89b389cde (MD5) Previous issue date: 2008-03-28 / The demand for technical information about castor crop in Rio Grande do Sul, has intensified in the past two years due to the government stimulation for the production of biofuels, through several applications of castor oil in the chemical and pharmaceutical industry and productivities achieved by castor crop in trials and experimental crops. Undoubtedly, this crop is an alternative to family farming diversification and to the development of the southern of the state, helping to create jobs and income. Research about the techmiques on castor planting are still incipient, lacking local technical information about the specie, difficulting its expansion. Thus, simultaneous actions are needed from several knowledge areas to generate technical information aiming to build a viable and sustainable castor production system. The objective of this work was generate technical information that will contribute to the construction of a production system that allows the commercial castor exploitation in the southern region of Brazil, through the evaluation of genotypes, times and densities of sowing. The test for evaluating cultivars have been conducted in three locations using seven varieties and six hybrids. The experiments of sowing time were planted in three places and three times, using four cultivars, two varieties and two hybrids. The density trial was composed of four cultivars, two varieties and two hybrids, where have been tested three sowing densities for varieties and hybrids. Ricinus communis. sowing times. sowing densities / A demanda por informações técnicas sobre a cultura da mamona no RS, se intensificou nos últimos dois anos, devido ao estímulo do governo para a produção de biocombustíveis, pelas diversas aplicações do óleo de mamona na indústria química e farmacêutica e pelos índices de produtividade alcançados pela cultura da mamona em ensaios e lavouras experimentais. Sem dúvida a cultura é uma alternativa para a diversificação da agricultura familiar e importante alternativa para impulsionar o desenvolvimento da Metade Sul do Estado, contribuindo na geração de empregos e renda. As pesquisas sobre prática de cultivo da mamona ainda são incipientes, havendo falta de informações técnicas regionalizadas sobre esta cultura, o que dificulta a expansão do cultivo. Desta forma, são necessárias ações conjuntas das diversas áreas de conhecimento para gerar informações técnicas para um sistema de produção de mamona viável à exploração econômica e sustentável. O objetivo deste trabalho foi gerar informações técnicas que venham a contribuir com a construção de um sistema de produção que permita a exploração comercial sustentável da mamona na região Sul do Brasil, através da avaliação de genótipos, épocas e densidades de semeadura. O ensaio de avaliação de cultivares foram conduzido em três locais utilizando sete variedades e seis híbridos. Os experimentos de época de semeadura foram semeados em três locais e três épocas, utilizando quatro cultivares, duas variedades e dois híbridos. O ensaio de densidade foi composto de quatro cultivares, duas variedades e dois híbridos, onde foram testadas três densidades para variedades e três para híbridos.
53

Profiling of rough terrain

Becker, Carl Martin 26 November 2009 (has links)
In the automotive industry one of the methods used in accelerating the design, testing and development of a system or a vehicle is the use of virtual vehicle simulations. The simulations cut costs in the form of fewer prototypes required for actual testing and accelerated fault finding in the design of a system. The simulation results are very dependent on the model used for the simulation and the inputs to the system. Feasible results can often be obtained with a simplified model if the correct input data is supplied to the simulation. In South Africa, the commercial, military and off-road vehicle industries mainly use the test tracks at the Gerotek Test Facilities for ride comfort and durability tests over repeatable terrains. Terrain profiles of these tracks are not available and cannot be measured using commercially available inertial profilometers due to the severe roughness of the terrain. This study concentrates on obtaining the input data in the form of the terrain profile used for vehicle simulations and field tests in which a vehicle is driving on rough terrains. The input data is referred to as the profile of the terrain and the profiled terrains are the actual terrains used for testing. Three different methods are used in measuring the profile of the terrain namely a mechanical profilometer, photogrammetry and a 3-D scanner using a laser displacement sensor. These methods are evaluated by profiling the same section of the Belgian paving and calculating the Displacement Spectral Densities. The most efficient method is used to profile additional terrains. The terrain profiles thus obtained is used as input to an existing off-road vehicle simulation model built in MSC Adams View. This model has previously been verified over discrete obstacles where excellent correlation with experimental results was obtained. Comparison between simulated and measured results over the terrains profiled in this study also gives good correlation, establishing further confidence in the measured terrain profiles. / Dissertation (MEng)--University of Pretoria, 2009. / Mechanical and Aeronautical Engineering / unrestricted
54

The Conservation Value of Residential Landscapes for Native Bird Communities: Patterns, Processes, and Management Implications

Lerman, Susannah Beth 01 September 2011 (has links)
Urbanization, as it transforms natural biotic systems into human-dominated landscapes, is recognized as one of the greatest threats to biodiversity throughout the world. Furthermore, urban dwellers are becoming increasingly disconnected with the natural world. Here I investigate whether residential landscape designs that mimic the natural environment can provide habitat for native birds. First I uncover some of the patterns of bird distribution in residential yards by incorporating habitat features, urbanization measurements and socioeconomic factors with bird monitoring data into a multivariate analysis. The results indicate that native birds associate with neighborhoods with native plants and shrubs, neighborhoods closer to desert tracts, and higher income neighborhoods. Very few bird species associate with low income and predominantly Hispanic neighborhoods. Additional analyses based on social survey data demonstrate that residents notice the varying levels of bird variety in their neighborhood. Second, I address whether perceived habitat quality differs between residential landscape designs by testing foraging decisions at artificial food patches. Birds foraging in yards landscaped with native plants consume fewer resources than birds foraging in exotic landscaped yards. This suggests that alternative food sources are more available in the native landscaped yards, indicating better quality habitat. Third, I investigate the relationship between native bird diversity and neighborhoods with a Homeowner Association (HOA). Neighborhoods with an HOA have higher native bird diversity, perhaps due to an active and enforceable landscape maintenance plan. I suggest an HOA adapt features from the Sustainable Sites Initiative to further improve habitat conditions for native birds and other wildlife. Results from the Dissertation support the implementation of native landscaping in residential yards to help reverse the loss of urban biodiversity. Consequentially, these landscapes will provide positive opportunities for urban dwellers to reconnect with the natural world.
55

Many Body Effects in the Electron Gas And Position Annihilation / Many Body Effects

Hede, Brian Bertrand John 11 1900 (has links)
<p> A number of questions are examined concerning many body correlations in connection with electron gas at metallic densities (2 < = rs <= 5.7) and the annihilation of a positron in simple metals, by means of a technique involving the two particle correlation Green's function. Estimates are made of low temperature contributions to angular correlation data, which describe the momentum distribution of annihilating electron positron pairs, in the form of smearing at the sharp cutoff corresponding to the Fermi momentum from electron- and positron- photon interactions, and in the form of broad tails beyond the cutoff resulting from the high-momentum components introduced into the electron wave function by the presence of a periodic crystal lattice. </p> <p> Phonon effects are introduced into the perturbation expansion of the two particle Green's function describing an electron positron pair. A calculation of the lowest order phonon contribution seems to indicate that such effects do not explain the smearing at the Fermi momentum. </p> <p> A Green's function calculation of the first-order enhancement of the lattice tails, due to the positron-electron correlation, is made by introducing particle-lattice interactions explicitly in a model based on a simple metal such as sodium. It considers a weak potential and treats as zero the lattice components corresponding to other than nearest-neighbours points in reciprocal lattice space. The enhancement for rs =4, which is almost a constant, is very similar to that for the main part of angular correlation data. This indicates that, for simple metals at least, angular correlation data can be interpreted directly from a free-particle model. </p> <p> Short-range correlations among opposite-spin electrons are examined by field-theoretic techniques as a step to obtaining a fundamental understanding of the correlations among electrons at metallic densities. A calculation of the p.d.f. for opposite-spin electrons is positive over a wide range of metallic densities and seems to account for short-range correlations of the Coulomb hole through the multiple scattering of particle-particle ladders. </p> / Thesis / Doctor of Philosophy (PhD)
56

Investigating the Presence and Population Densities of Plant-Parasitic Nematodes and the Influence of Soil Region, Cropping Practices and Soil Properties on these Nematodes in Corn Fields in Ohio

Simon, Abasola Compton Maurice 26 May 2015 (has links)
No description available.
57

Land-Use Structure And Population And Employment Densities: Empirical Analysis Of The Columbus (Ohio) Metropolitan Area

Lu, Jia 14 April 2008 (has links)
No description available.
58

Capillary Study on Geometrical Dependence of Shear Viscosity of Polymer Melts

Lin, X., Kelly, Adrian L., Woodhead, Michael, Ren, D.Y., Wang, K.S., Coates, Philip D. January 2014 (has links)
No
59

Host-parasite interaction between the potato tuber rot nematode (Ditylenchus destructor), stem nematode (Ditylenchus dipsaci) and potato

Mutua, Peter Mwaura 02 February 2015 (has links)
ZUSAMMENFASSUNG Nematoden rufen weltweit erhebliche Verluste in der Kartoffelproduktion hervor. Der Knollenfäule-Nematode Ditylenchus destructor Thorne 1945 und das Stock-und Stangelälchen Ditylenchus dipsaci Kühn 1857 Filipjev, 1936, verursachen Läsionen an der Kartoffelknolle, was deren Qualität und Marktwert verringert. Diese Nematoden sind aufgrund ihres umfangreichen Wirtspflanzenspektrums schwierig zu kontrollieren und werden daher in vielen Ländern als Quarantäne-Nematoden geführt. In der hier vorliegenden Doktorarbeit wurden Experimente durchgeführt, um die Wechselwirkung von Kartoffel mit jeder dieser beiden Nematodenarten zu untersuchen. Verschiedene Populationen von D. destructor und D. dipsaci wurden molekular und morphometrisch charakterisiert. Die Gensequenz kodierend für die Untereinheit I der Cytochrom Oxidase (COI) auf der mitochondrialen DNA (mtDNA) wurde analysiert, um eine phylogenetische Beziehung zwischen den untersuchten Populationen darzustellen. Die Ergebnisse zeigten zwei deutlich getrennte Cluster für die D. destructor und die D. dipsaci Populationen. Eine Diskriminanzanalyse der morphometrischen Daten von Männchen und Weibchen von D. destructor und D. dipsaci Populationen verdeutlichte, dass diese beiden Arten mittels a-ratio und ihrem Durchmesser unterschieden werden können. Die sich ergänzende Kombination von molekularen und morphometrischen Untersuchungen ermöglichte die Identifikation der untersuchten Arten. Es wurden zwei Gewächshausexperimente mit 25 angebauten Kartoffelsorten durchgeführt, um diese auf Resistenz und Toleranz gegenüber Nematoden zu testen. Dazu wurde ein Standard-Screening Protokoll entwickelt. Resistenz und Toleranz wurden gemäß der derzeitigen Definition (Nematologie) bewertet. Die relative Anfälligkeit und äußere Verletzung der Kartoffelknolle stellten sich als beste Parameter für die Beurteilung der Resistenz respektive der Toleranz heraus. Alle 25 untersuchten Kartoffelsorten waren weder resistent noch tolerant gegenüber D. destructor oder D. dipsaci. Jedoch wurden Unterschiede in der Toleranz der Sorten festgestellt. Im Vorfeld zum Pflanzenexperiment wurden die Populationsdichten von D. destructor und D. dipsaci und deren Einfluss auf Ertragsverlust untersucht. Die initiale Populationsdichte hatte einen signifikanten Effekt auf den Schaden an der Kartoffelknolle und den Fortpflanzungsfaktor der Nematoden unter Gewächshausbedingungen. D. destructor verursachte Schäden bereits bei einer geringeren initialen Populationsdichte als D. dipsaci. Unter Klimakammerbedingungen wurde gezeigt, dass die Temperatur Einfluss auf die Schadensrate von D. destructor und D. dipsaci an Kartoffelknollen nimmt. Im Gegensatz zu einer Temperatur von 16°C waren 26°C sowohl optimal für die Vermehrung von D. destructor als auch für D. dipsaci. Obwohl für D. destructor und D. dipsaci unterschiedliche Temperaturanforderungen beschrieben wurden, verursachten beide Arten in ähnlichen Temperaturbereichen äußere Verletzungen an der Kartoffelknolle. Beauveria bassiana ist ein weltweit verbreiteter Pilz, der vor allem zur Bekämpfung von Insektenschädlingen in der Kartoffelproduktion Anwendung findet. Doppelbefall von Kartoffeln mit B. bassiana Sporensuspensionen im Boden mit D. destructor oder D. dipsaci begünstigte die Nematoden, was zu einer erhöhten Nematodenfortpflanzung und Knollenbeschädigung führte. B. bassiana allein war nicht schädlich für die Kartoffel. Es wurde vermutet, dass B. bassiana eine indirekte Rolle in der Wechselwirkung Nematode-Kartoffel spielt. Vorschläge für zukünftige Experimente werden angebracht, die einen weiteren Beitrag zu den hier vorgestellten Studien leisten können.
60

Influência de cultivares e densidades de plantas sobre a eficácia da proteção química no patossistema soja-phakopsora pachyrrizi / Influence of cultivars and plant densities on the effectiveness of chemical protection in pathosystem soybean- Phakopsora pachyrrizi

Domingues, Lucas da Silva 26 February 2010 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Aiming to evaluate the response of ten soybean cultivars subjected to three arrangements of plants and eight fungicide programs in terms of expression and the development of Asian rust, penetration of light on the canopy, productivity and yield components of soybean experiment was conducted during the 2008/2009 season, in Itaara / RS. In the field, cultivars FCep 55, BMX Apollo, BMX Titan, BRS 243, A 8000, CD 214, NK 70, BRS Pampa, FCep 59 and Monasca were subjected to densities off 160, 300 and 440 thousand plants ha-1 and eight programs fungicide management: P1- treatment control, P2 - epoxiconazole + pyraclostrobin with application to closing the row space and 21 days after the first application; P3 - epoxiconazole + pyraclostrobin application to closing the row space and 28 days; P4 - epoxiconazole + pyraclostrobin with application in R1 and 21 days; P5 - epoxiconazole + pyraclostrobin with applications closing the row space, 21 days after the first application and the third application 14 days after the second; P6 - tebuconazole + carbendazin with application in closing the row space and 21 days after the first application; P7 - tebuconazole + carbendazin application to close row space and 28 days after and P8 - tebuconazole + carbendazin with application in R1 and 21 days. The variables were: percentage of light penetration within the canopy, Area under the progress disease curve (AUPDC), grain yield and yield components. The experimental design was a randomized block, with 4 replications and three-way design (10 cultivars x 3 planting densities x 8 fungicide management programs). For percentage of light penetration in the canopy, BMX Apollo cultivar performed better with values close to 1% when subjected to higher density. For the variables AUPDC and productivity cultivars might be grouped as responsive, not responsive and unresponsive to reduce the plant population. The responsive cultivars for AUPDC were FCep55, BMX Apollo, BRS 243, CD 214, has had this behavior to yield the cultivars FCep 55, A 8000, BMX Titan, BRS 243 and NK 70. Management programs had the same trend for these two variables where the program with three applications of epoxiconazole + pyraclostrobin showed lower AUPDC value and higher yield. The number of branches per plant showed that all cultivars reduce the production of branches when exposed to high density, which resulted in condensing the grain on the main stem, especially the cultivar BMX Apollo that concentrated 99.84% of the grain on the main stem and the higher density was only 0.02 branches for plant. For the yield components number of pods for m2 and number of grains for pod was significant difference only for the cultivars and plant density. For densities, the higher density of plants resulted in reducing the number of pods for area, grains per pod, among the cultivars NK 70 showed the highest number of pods for m2 and the cultivar BMX Apollo largest number of grains for pod. The mass of 1000 grains was the variable with little variation among worked. There interaction between programs and cultivars, where the maturity cultivars achieved the largest masses. For the participation of thirds in the number of pods, there was only difference among cultivars where the variability of response between the cultivars shows that this variable has genetic domain. / Com o objetivo de avaliar a resposta de dez cultivares de soja submetidas a três arranjos de plantas e à aplicação de oito programas de manejo fungicida no que tange à expressão e ao desenvolvimento da ferrugem asiática, penetração de luminosidade no dossel vegetativo, produtividade e componentes da produtividade da cultura da soja foi realizado experimento durante a safra agrícola 2008/2009, em Itaara/RS. Em campo, as cultivares FCep 55, BMX Apolo, BMX Titan, BRS 243, A 8000,CD 214,NK 70, BRS Pampa, FCep 59 e Monasca foram submetidas às densidades 160, 300 e 440 mil plantas ha-1 e a oito programas de manejo fungicida: P1- testemunha, P2 epoxiconazol +piraclostrobina com aplicação no fechamento da entre linha e 21 dias após a primeira aplicação; P3 epoxiconazol + piraclostrobina aplicado no fechamento da entre linha e 28 dias após; P4 epoxiconazol + piraclostrobina com aplicação em R1 e 21 dias após; P5 epoxiconazol + piraclostrobina com aplicações em fechamento das entre linhas, 21 dias após a primeira aplicação e com terceira aplicação 14 dias após a segunda; P6 tebuconazol + carbendazin com aplicação no fechamento da entre linha e 21 dias após a primeira aplicação; P7 tebuconazol + carbendazin aplicado no fechamento da entre linha e 28 dias após e P8 tebuconazol + carbendazin com aplicação em R1 e 21 dias após. As variáveis avaliadas foram: percentual de penetração de luz no dossel vegetativo, área abaixo da curva de progresso da doença (AACPD), rendimento de grãos e componentes do rendimento. O delineamento experimental utilizado foi o de blocos ao acaso, com 4 repetições, no esquema trifatorial (10 cultivares x 3 densidades de plantas x 8 programas de manejo fungicida). Para a variável percentual de penetração de luz no dossel vegetativo, a cultivar BMX Apolo obteve melhor desempenho com valores próximos a 1% quando submetida à maior densidade. Para as variáveis AACPD e produtividade, as cultivares puderam ser agrupadas como responsivas, não- responsivas e indiferentes à redução da população de plantas. As cultivares responsivas para AACPD foram FCep 55, BMX Apolo, BRS 243, CD 214, já para produtividade tiveram esse comportamento as cultivares FCep 55, A 8000, BMX Titan, BRS 243 e NK 70. Os programas de manejo tiveram a mesma tendência para essas duas variáveis, onde o programa com três aplicações de epoxiconazol + piraclostrobina apresentou menor valor de AACPD e maior rendimento. O número de ramos por planta mostrou que todas as cultivares reduzem a produção de ramos quando expostos a condições adensamento, o que refletiu em concentração da massa de grãos na haste principal, com destaque para a cultivar BMX Apolo que concentrou 99,84% da massa de grãos na haste principal e na maior densidade teve apenas 0,02 ramos por planta. Para os componentes do rendimento número de legumes por m2 e número de grãos por legume, houve diferença significativa somente para os fatores cultivares e densidade de plantas isoladamente. Para as densidades, o adensamento de plantas resultou na redução do número de legumes por unidade de área e de grãos por legume, já entre as cultivares, a cultivar NK 70 apresentou o maior número de legumes por m2 e a cultivar BMX Apolo, o maior número de grãos por legume. A massa de 1000 grãos foi a variável com menor variação dentre as trabalhadas, havendo interação entre os programas e as cultivares, onde as cultivares de ciclo precoce obtiveram as maiores massas. Para a participação dos terços no número de legumes, houve diferença somente entre as cultivares onde a variabilidade de resposta entre os materiais aponta para que essa variável tenha domínio genético.

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