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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.
41

Quantitative trait loci affecting the agronomic performance of a Sorghum bicolor (L.) Moench recombinant inbred restorer line population

Moran Maradiaga, Jorge Luis 30 September 2004 (has links)
Lately the rate of genetic gain in most agronomic crop species has been reduced due to several factors that limit breeding efficiency and genetic gain. New genetic tools and more powerful statistical analyses provide an alternative approach to enhance genetic improvements through the identification of molecular markers linked to genomic regions or QTLs controlling quantitative traits. The main objective of this research was to identify genomic regions associated with enhanced agronomic performance in lines per se and hybrid combination in Sorghum bicolor (L.) Moench. A population composed of 187 F5:6 recombinant inbred lines (RIL) was derived from the cross of restorer lines RTx430 and RTx7000. Also, a testcross hybrid population (TCH) was developed by using each RIL as a pollinator onto ATx2752. A linkage map was constructed using 174 marker loci generated from AFLP and SSR primer combinations. These markers were assigned to 12 different linkage groups. The linkage map covers 1573 cM with marker loci spaced at an averaged 9.04 cM. In this study, 89 QTL that control variation in seven different morphological traits were identified in the recombinant inbred line population, while in the testcross hybrid population, 79 QTL were identified. These traits included grain yield, plant height, days to mid-anthesis, panicle number, panicle length, panicle exsertion and panicle weight. These putative QTL explained from 4 to 42% of the phenotypic variation observed for each trait. Many of the QTL were not consistent across populations and across environments. Nevertheless, a few key QTL were identified and the source of the positive additive genetics isolated. RTx7000 was consistently associated with better agronomic performance in RIL, while in testcrosses, RTx430 was. Some genomic regions from RTx7000 may be utilized to improve RTx430 as a line per se. However, it is very unlikely that such regions will have a positive effect on the combining ability of RTx430 since testcross results did not reveal any transgressive segregants from the RIL population.
42

Εκτίμηση αντοχής αυτοσυμπυκνούμενου σκυροδέματος με τη μέθοδο της ωριμότητας [maturity method] / Maturity method for ssr concrete

Αγγελόπουλος, Γρηγόρης 12 November 2007 (has links)
Η παρούσα διπλωματική εργασία κάνει μια σύντομη αναφορά στα θεωρητικά προσομοιώματα εκτίμησης της θλιπτικής αντοχής του αυτοσυμπυκνούμενου σκυροδέματος (ΑΣΣ), όπως και του συμβατού σκυροδέματος. Το ΑΣΣ είναι ένας τύπος σκυροδέματος που είναι ικανός να ρέει στους ξυλότυπους, χωρίς να παρουσιάζει διαχωρισμό, και μπορεί να πληρώσει ομοιόμορφα και πλήρως κάθε σημείο του ξυλότυπου ρέοντας αποκλειστικά και μόνο λόγω του ίδιου βάρους του, χωρίς καμία ανάγκη δόνησης ή κατανάλωσης άλλου είδους ενέργειας. Η διαδικασία για την εκτίμηση της αντοχής του σκυροδέματος γίνεται με τη χρήση της μεθόδου της ωριμότητας. Παρουσιάζονται, επίσης, κάποια εργαστηριακά αποτελέσματα προσδιορισμού τιμών αντοχής συγκεκριμένων μιγμάτων από σκυρόδεμα, τα οποία υπολογίστηκαν με τη χρήση της μεθόδου αυτής. / About ssr concrete characteristics. Estimating the strength of ssr concrete using the maturity method. There is also an attempt in the laboratory of estimating strength of different mixtures of concrete
43

Investigations into the Shear Strength Reduction method using distinct element models

Fournier, Mathew 11 1900 (has links)
This thesis reports a detailed investigation into the use of the Shear Strength Reduction (SSR) method to determine factor of safety values in discontinuum models using the Universal Distinct Element Code. The SSR method depends on the definition of failure within the model and two different criteria were compared: the numerical unbalanced force definition and a more qualitative displacement-monitoring based method. A parametric study was first undertaken, using a simple homogeneous rock slope, with three different joint networks representing common kinematic states. Lessons learned from this study were then applied to a more complex case history used for validation of the SSR method. The discontinuum models allow for the failure surface to propagate based on constitutive models that better idealize the rockmass than simpler methods such as limit equilibrium (e.g. either method of slices or wedge solutions) and even numerical continuum models (e.g. finite difference, finite element). Joints are explicitly modelled and can exert a range of influences on the SSR result. Simple elasto-plastic models are used for both the intact rock and joint properties. Strain-softening models are also discussed with respect to the SSR method. The results presented highlight several important relationships to consider related to both numerical procedures and numerical input parameters. The case history was modelled similar to how a typical forward analysis would be undertaken: i.e. simple models with complexities added incrementally. The results for this case generally depict a rotational failure mode with a reduced factor of safety due to the presence of joints within the rockmass when compared to a traditional limit equilibrium analysis. Some models with large persistence of steeply dipping joints were able to capture the actual failure surface. Softening models were employed in order to mimic the generation and propagation of joints through the rockmass in a continuum; however, only discontinuum models using explicitly defined joints in the model were able to capture the correct failure surface.
44

Genetic and Hormonal Regulation of Stem Vascular Tissue Development In Flax (Linum usitatissimum L.)

McKenzie, Ryan Unknown Date
No description available.
45

Investigations into the Shear Strength Reduction method using distinct element models

Fournier, Mathew 11 1900 (has links)
This thesis reports a detailed investigation into the use of the Shear Strength Reduction (SSR) method to determine factor of safety values in discontinuum models using the Universal Distinct Element Code. The SSR method depends on the definition of failure within the model and two different criteria were compared: the numerical unbalanced force definition and a more qualitative displacement-monitoring based method. A parametric study was first undertaken, using a simple homogeneous rock slope, with three different joint networks representing common kinematic states. Lessons learned from this study were then applied to a more complex case history used for validation of the SSR method. The discontinuum models allow for the failure surface to propagate based on constitutive models that better idealize the rockmass than simpler methods such as limit equilibrium (e.g. either method of slices or wedge solutions) and even numerical continuum models (e.g. finite difference, finite element). Joints are explicitly modelled and can exert a range of influences on the SSR result. Simple elasto-plastic models are used for both the intact rock and joint properties. Strain-softening models are also discussed with respect to the SSR method. The results presented highlight several important relationships to consider related to both numerical procedures and numerical input parameters. The case history was modelled similar to how a typical forward analysis would be undertaken: i.e. simple models with complexities added incrementally. The results for this case generally depict a rotational failure mode with a reduced factor of safety due to the presence of joints within the rockmass when compared to a traditional limit equilibrium analysis. Some models with large persistence of steeply dipping joints were able to capture the actual failure surface. Softening models were employed in order to mimic the generation and propagation of joints through the rockmass in a continuum; however, only discontinuum models using explicitly defined joints in the model were able to capture the correct failure surface.
46

Ανάλυση και έλεγχος ταχύτητας ατμοστροβίλου σε ΣΗΕ

Γιαννόπουλος, Ανδρέας 31 May 2012 (has links)
Κύριος στόχος της εργασίας αυτής είναι η κατανόηση της διαδικασίας της μοντελοποίησης Συστήματος Ηλεκτρικής Ενέργειας, και πως η διαδικασία αυτή βοηθά στην αντιμετώπιση του φαινομένου της υποσύγχρονης αντίδρασης. Το φαινόμενο αυτό εμφανίζεται όταν ΣΗΕ στο οποίο ενυπάρχει αντιστάθμιση σε σειρά συνδέεται με ατμοστρόβιλο. Αντικείμενο μελέτης της εργασίας αυτής είναι με ποιο τρόπο η εν σειρά αντιστάθμιση συντελεί στην εμφάνιση του φαινομένου. Μελετώνται αναλυτικές υπολογιστικές μέθοδοι διάγνωσης του, και τέλος προτείνονται τρόποι αντιμετώπισης. / The main target of this project is the understanding of modeling an electrical system, and how can this help in the specific case of sub synchronous resonance studies. This phenomenon occurs when a series compensated electrical system is connected with a steam turbine, sometimes resulting in torsional stress. In addition, computational methods for the study of the phenomenon are presented. Last, but not least, countermeasures are suggested.
47

Analýza genetické variability jírovce maďalu pomocí DNA markerů

Bačovský, Václav January 2015 (has links)
Some species of the genus Aesculus are every year heavily infested by horse chestnut leaf miner (Cameraria ohridella), whose larvae are mining the leaves, and under appropriate conditions may damage up to 100% of the leaf area. The effect of lower defense capability of infested trees lead to invasion of fungal (Erysiphe flexuosa, Guignardia aesculi) and bacterial (Pseudomonas syringae pv. aesculi) pathogens, and later to higher mortality of infected individuals. In this study were measured the genetic diversity of species A.hippocastanum, A. turbinata, A. glabra, A. parviflora, A. glabra var. arguta, A. x carnea, A. marilandica, A. pavia, and their genotypes with different susceptibility to the leaf miner. Analysis of 8 microsatellite loci, using the SB buffer for separation, showed high polymorfic information content 0.45 -- 0.77 (0,60 in average) and high genetic diversity. For each loci was found average 5.5 aleles. During two vegetation period, leaf area damage of these genotypes was evaluated in statistical software Assess 2.0. Different pressure of leaf miner and different development at each locality was recorded, and even in some cases lower damage was found, in one case it occured permanently. According to the data obtained, the pathological scale was established and the dendogram of similarity was created. Three groups of resistant, non -- resistant and immune individuals were distinguished and five main section of Aesculus was found. By cloning and analysing the inner transcribed spacers, ITS1 and ITS2, inner and inter species variability was examined. For the sequence of hybrid species A. x carnea no compliance was found in NBCI, therefore first sequence of this genotype was obtained.
48

Detecção da diversidade e associação de Lasiodiplodia theobromae com o cajueiro utilizando marcadores microssatélites. / Detection and diversity of Lasiodiploidia theobromae assiciated with cashew plants using microssatellites markers.

Farias, Fábio Costa January 2008 (has links)
FARIAS, F. C. Detecção da diversidade e associação de Lasiodiplodia theobromae com o cajueiro utilizando marcadores microssatélites. 2008. 42 f. Dissertação (Mestrado em Agronomia/Fitotecnia) - Centro de Ciências Agrárias, Universidade Federal do Ceará, Fortaleza, 2008. / Submitted by Francisco Lacerda (lacerda@ufc.br) on 2014-07-02T19:50:47Z No. of bitstreams: 1 2008_dis_fcfarias.pdf: 910648 bytes, checksum: 11c32ed2ac28af3a0d3eb679e579bd04 (MD5) / Approved for entry into archive by José Jairo Viana de Sousa(jairo@ufc.br) on 2014-07-02T20:07:46Z (GMT) No. of bitstreams: 1 2008_dis_fcfarias.pdf: 910648 bytes, checksum: 11c32ed2ac28af3a0d3eb679e579bd04 (MD5) / Made available in DSpace on 2014-07-02T20:07:46Z (GMT). No. of bitstreams: 1 2008_dis_fcfarias.pdf: 910648 bytes, checksum: 11c32ed2ac28af3a0d3eb679e579bd04 (MD5) Previous issue date: 2008 / The cashew crop is one of the most important agribusiness activity in northeastern Brazil, mainly due to its social and economic impact in that region. Nevertheless, severe outbreaks of gummosis and black branch dieback, both caused by the fungus Lasiodiplodia theobromae have imposed great losses under semi-arid conditions. Presently, these diseases are the most important ones over semi-arid conditions in Northeast Region. However, the limited amount of basic knowledge about population biology, genetic structure and pathogen, host and environment interaction are likely to hinder the efforts to manage this pathogen. This study was developed in order to establish a L. theobromae population associated with cashew plant from different ecological regions in the northeastern Brazil, to determine the survival endophytic ability of this fungus in cashew tissues and to characterize this population by using microsatellite markers. Initially, samples of cashew stems were gathered from three natural ecosystems in Brazil in order to isolate L. theobromae. A population of 41 isolates associated with cashew was obtained. Bioassays aiming to determine the surviving ability of this fungus in non infected tissues close to gummosis lesions were conducted using sampled stems. A subpopulation of 15 isolates of L. theobromae was used for DNA extraction followed by polimerase chain reaction (PCR) using 15 oligonucleotides primers designed to amplify microsatellites regions. PCR products were observed on agarose gel in ethidium bromide electrophoresis and analyzed by the unweighted pair-group method with arithmetic mean (UPGMA) by the Nei and Li similarity coefficient. L. theobromae was successfully isolated from cashew tissues as far as 90 cm from the border of the gummosis lesion in both up and down directions. This result confirms the endophytic behavior of this fungus in cashew plant. A great genetic variability of L. theobromae population was observed as determined by 16 similarities groups varying from 91% to 5%. None isolate achieved 100% similarity. The greatest similarity was found between pathogenic and endophytic isolates. / A cultura do cajueiro representa uma das mais importantes atividades agroindustriais do Nordeste do Brasil, sobretudo pelo seu caráter social e econômico para esta região. Entretanto, a ocorrência epifítica de doenças como a resinose e a podridão-preta-da-haste, ambas causadas pelo fungo Lasiodiplodia theobromae, têm produzido severas perdas principalmente nas regiões semi-áridas. Essas já assumem a posição de principais doenças em algumas regiões do semi-árido nordestino. Entretanto, os conhecimentos básicos sobre a biologia populacional, constituição genética e interação do patógeno com as plantas hospedeiras, por exemplo, são reduzidos e superficiais, não permitindo significativos avanços no manejo dessas enfermidades. Este estudo teve como objetivos estabelecer uma população de isolados L. theobromae associados ao cajueiro em diferentes micro-regiões do nordeste brasileiro, determinar a capacidade deste fungo sobreviver endofiticamente em tecidos de cajueiro e caracterizar geneticamente essa população usando marcadores microssatélites. Inicialmente, foram coletadas amostras de caules de cajueiro em três ecossistemas naturais brasileiros visando isolar o patógeno. Foi estabelecida uma população de 41 isolados de L. theobromae associados ao cajueiro. Bioensaios visando a determinação da sobrevivência do fungo em tecidos não infectados, mas próximos às lesões foram desenvolvidos a partir de amostras de caules com resinose. Uma sub-população de 15 isolados de L. theobromae foi usada na extração de DNA e posterior submissão a reações de polimerase (PCR) em cadeia usando 15 primers flanqueadores de regiões contendo seqüências simples repetidas (microssatélites). Os produtos amplificados do PCR foram observados em gel de eletroforese corados com brometo de etídio e analisados pelo método de agrupamento não balanceado baseado na média aritmética (UPGMA), estimando-se as similaridades genéticas pelo coeficiente de Nei e Li. L. theobromae foi isolado de tecidos do caule do cajueiro até 90 cm de distância da extremidade da lesão característica de resinose nos dois sentidos (ascendente e descendente) em relação à lesão, confirmando o comportamento endofítico desse fungo em cajueiro. Uma grande variabilidade genética da população avaliada, representada por 16 grupos de similaridade variando de 91% a 5%, foi observada. Nenhum isolado foi igual (100% similaridade). As maiores similaridades (91%) foram observadas entre isolados comprovadamente patogênicos e supostamente endofíticos.
49

Výzkum a ověřování metod pro efektní studium a mapování genomů Glycime Max (L.) a Prunus Persica (L.)

Baránek, Miroslav January 2004 (has links)
No description available.
50

Desenvolvimento de marcadores microssatélites para Stryphnodendron adstringens (barbatimão - Fabaceae) / Development of microssatellite markers for Stryphnodendron adstringens (barbatimão - Fabaceae)

Barateli, Luciana Oliveira 27 August 2018 (has links)
Submitted by Franciele Moreira (francielemoreyra@gmail.com) on 2018-11-05T13:39:32Z No. of bitstreams: 2 Dissertação - Luciana Oliveira Barateli - 2018.pdf: 3641421 bytes, checksum: a96d12f5fce8d5c02a9793dec50ebfbf (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2018-11-05T14:49:58Z (GMT) No. of bitstreams: 2 Dissertação - Luciana Oliveira Barateli - 2018.pdf: 3641421 bytes, checksum: a96d12f5fce8d5c02a9793dec50ebfbf (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2018-11-05T14:49:58Z (GMT). No. of bitstreams: 2 Dissertação - Luciana Oliveira Barateli - 2018.pdf: 3641421 bytes, checksum: a96d12f5fce8d5c02a9793dec50ebfbf (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2018-08-27 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Stryphnodendron adstringens presents a wide geographical distribution, being predominant in regions of Cerrado sensu stricto and is popularly known as "barbatimão". It is a species widely used in herbal medicine because of its anti-inflammatory, antibacterial and antiulcerogenic potential. The Cerrado’s removal of vegetation cover reduces significantly the number of several native species, among them S. adstringens. Thus, it is important that efficient strategies for the use and conservation of this species are drawn. In order to provide molecular tools for studies of genetic diversity and conservation of S. adstringens, the present work had the objective of developing microsatellite markers for the species. Genomic DNA was obtained from leaf tissue using the CTAB protocol. The identification of the microsatellite regions and the design of the primers were performed using the QDD program modules. From the identified microsatellite regions, 20 pairs of primers were designed, 14 of which flank microsatellite regions composed of dinucleotides, four by tetranucleotides and two by pentanucleotides. Initially, four individuals were used for the standardization tests of the PCR protocol and annealing temperatures. Subsequently, 48 individuals were selected, distributed in three populations, to evaluate polymorphism via 6% polyacrylamide gel. Of the 20 pairs of primers evaluated, 16 presented polymorphic amplification products and four monomorphic amplification products. Considering the 16 polymorphic markers, the number of alleles varied between two (SadH19) and 13 (SadH13), with a mean of seven alleles per locus. The observed heterozygosity (Ho) and expected (He) and PIC values were 0.506, 0.543, 0.635, respectively. The mean Hmax value founded (65,519) indicates values of genetic diversity that can be considered medians for this set of loci evaluated in three populations of S. adstringens. On the other hand, although genetic diversity is median, this set of 16 polymorphic markers exhibited a ombined probability of paternity exclusion high (0.9999983) and combined probability of genetic identity low (3,49x10-15). The analysis of variance of allelic frequencies presented significant values for two of the three estimated statistics with f not significant 0.050, significant θ equal to 0,329 and F in the overall value also significant 0.360. Thus, it can be concluded that the panel of polymorphic markers developed for S. adstringens is highly informative and indicated for population genetic studies for the species. Another important factor is that these markers can be tested in other evolutionarily close species for the availability of microsatellite markers, without the need to develop new primers. / Stryphnodendron adstringens apresenta ampla distribuição geográfica, sendo predominante em regiões de Cerrado stricto sensu e é conhecida popularmente como “barbatimão”. É uma espécie utilizada na medicina fitoterápica por seu potencial anti-inflamatório, antibacteriano e antiulcerogênico. A retirada de cobertura vegetal do Cerrado diminui significativamente o número de diversas espécies nativas, dentre elas S. adstringens. Dessa forma, é importante que sejam traçadas estratégias eficientes para o uso e a conservação dessa espécie. A fim de disponibilizar ferramentas moleculares para estudos de diversidade genética e conservação de S. adstringens, o objetivo desse estudo foi desenvolver marcadores microssatélites e estimar o potencial informativo desses marcadores para subsidiar estudos de genética populacional da espécie. A identificação das regiões microssatélites e o desenho dos primers foram realizados usando o programa QDD. Inicialmente, foram utilizados quatro indivíduos para os testes de padronização do protocolo de PCR e temperaturas de anelamento. Posteriormente, foram selecionados 48 indivíduos, provenientes de três populações, para avaliação de polimorfismo via gel de poliacrilamida a 6%. A partir das regiões microssatélites identificadas, foram desenhados 20 pares de primers, sendo que 14 flanqueiam regiões microssatélites compostas por dinucleotídeos, quatro por tetranucleotídeos e dois por pentanucleotídeos. Dos 20 pares de primers avaliados, 16 apresentaram produtos de amplificação polimórficos e quatro monomórficos. Considerando os 16 marcadores polimórficos, o número de alelos variou entre dois (SadH19) e 13 (SadH13), com uma média igual a sete alelos por loco. Os valores das médias da heterozigosidade observada (Ho) e esperada (He) e do PIC foram iguais a 0,506, 0,543, 0,635 respectivamente. A proporção da diversidade máxima encontrada foi de 65%, o que indica valores de diversidade genética que podem ser considerados medianos para esse conjunto de locos avaliados em três populações de S. adstringens. Por outro lado, embora a diversidade genética seja mediana, esse conjunto de 16 marcadores polimórficos exibiu uma probabilidade de exclusão de paternidade combinada alta (0,999983) e uma probabilidade de identidade combinada baixa (3,49x10-15). A análise de variância das frequências alélicas apresentou valores significativos para duas das três estatísticas estimadas com f não significativo 0,050, θ significativo igual a 0,329 e F no valor global também significativo 0,360. Assim, pode-se concluir que o painel de marcadores polimórficos desenvolvidos para S. adstringens é altamente informativo e indicado para estudos genéticos populacionais para a espécie. Outro fator importante é que esses marcadores podem ser testados em outras espécies próximas evolutivamente para possível disponibilização de marcadores microssatélites, sem a necessidade de desenvolvimento de novos primers.

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