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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.
1001

Microbial Activity in Sediments: Effects on Soil Behavior

Rebata-Landa, Veronica 23 August 2007 (has links)
Microorganisms have played a critical role in geological processes and in the formation of soils throughout geological time. It is hypothesized that biological activity can also affect soil properties in short engineering time-scales. Bioactivity in sediments is determined by the classical limiting factors (i.e., nutrients, water, C for biomass, temperature and pH) as well as by pore-size geometrical limits and mechanical interactions between bacterial cells and soil particles. These constraints restrict the range of grain size and burial depth where biomediated geochemical processes can be expected in sediments, affect the interpretation of geological processes and the development of engineering solutions such as bioremediation. When biological, geometrical and mechanical limiting factors are satisfied, bioactivity can be designed to alter the mechanical properties of a soil mass, including lowering the bulk stiffness of the pore fluid through controlled gas bio-generation, increasing the shear stiffness of the soil skeleton by biomineralization, and reducing hydraulic conduction through biofilm formation and clogging. Each of these processes can be analyzed to capture the bio-chemo-hydro-mechanical coupling effects, in order to identify the governing equations that can be used for process design. Design must recognize the implications of spatial variability, reversibility and environmental impacts.
1002

Effect of twist, fineness, loading rate and length on tensile behavior of multifilament yarn

Rypl, Rostislav, Vořechovský, Miroslav, Sköck-Hartmann, Britta, Chudoba, Rostislav, Gries, Thomas 03 June 2009 (has links) (PDF)
The idea underlying the present study was to apply twisting in order to introduce different levels of transverse pressure. The modified structure affected both the bonding level and the evolution of the damage in the yarn. In order to isolate this effect in a broader context, additional parameters were included in the experiment design, namely effects of loading rate, specimen length and filament diameter (directly linked to the fineness of the yarn). These factors have been studied in various contexts by several authors. Some related studies on involved factors will be briefly reviewed.
1003

ETHNICITY AND FERTILITY: THE FERTILITY EXPECTATIONS AND FAMILY SIZE OF MEXICAN-AMERICAN AND ANGLO ADOLESCENTS AND ADULTS, HUSBANDS AND WIVES (BIRTHS, HISPANIC).

SORENSON, ANN MARIE. January 1985 (has links)
Because pronatalist sentiments may be an important aspect of Mexican-American ethnic heritage, this research focuses on cultural as well as socioeconomic factors which may contribute to higher Mexican-American fertility. Language use and nativity are used as indirect indicators of identification with an ethnic culture. Wives' characteristics are generally considered adequate to the study of couples' fertility, but in light of earlier research by the author indicating the importance of cultural factors to the fertility expectations of Mexican-American adolescent males, characteristics of husbands as well as wives are included in this analysis. For this reason, the sample, which is drawn from the 1980 Census data for Arizona, Texas, and New Mexico, is limited to Mexican-American and Anglo women who have been married only once and live with their husbands. Two complementary methods of analysis are used. Linear regression describes the significance of husband's and wife's language use, nativity, and socioeconomic characteristics to mean family size. Parity progression ratios are used to study the contribution of these variables to the likelihood of the addition of one more child at each stage of the family building process. While wife's characteristics are sufficient to account for most of the variation observed in Anglo fertility, husband's socioeconomic characteristics significantly contribute to variation observed in the fertility of Mexican-American couples. Husbands' identification with Mexican-American culture may be somewhat more important to couples' fertility than that of their wives. This is consistent with research which suggests that children are more central to male sex role expectations as they are expressed in the context of Mexican-American culture than in that of Anglos. The measures of ethnic identity used in this study are clearly associated with socioeconomic status. The differential fertility of Anglos and Mexican Americans could be attributed to these differences. The association of Spanish language use and fertility has been linked to the lower opportunity costs represented by additional children to women who do not speak English proficiently. However, the analysis of these data, which compares structural and cultural explanations of fertility differentials, provides evidence of cultural effects as well as the effects of socioeconomic status on fertility.
1004

Male Combat, Paternal Care, and the Evolution of Male Biased Sexual Size Dimorphism in the Emei Moustache Toad (Leptobrachium boringii)

Hudson, Cameron 06 September 2012 (has links)
I describe the natural history and reproductive behaviours of the Emei Moustache Toad (Leptobrachium boringii), testing the hypotheses that the species exhibits resource defense polygyny, and that combat, and paternal care lead to the evolution of male-biased sexual size dimorphism. In this study I document combat behaviour and paternal care for the first time in this species. Between February and March of 2011 and 2012, 26 female and 55 male L. boringii from Mount Emei UNESCO World Heritage Site, Sichuan, China, were observed throughout the breeding season. Prior to the breeding season, males grow 10-16 keratinized maxillary spines, which fall off once the season has ended. Throughout this time, males construct and defend aquatic nests where they produce advertisement calls to attract females. In a natural setting, I documented 14 cases involving a total of 22 males where males used their moustaches for aggressive interaction, and nest take over was observed on seven occasions. Despite my predictions, neither male body size nor body condition significantly affects the outcome of an aggressive interaction, though this may be representative of a low sample size. Males were also observed to possess injuries resulting from combat. Combat trials conducted in artificial nests demonstrated heightened aggression from resident males towards intruders. Genetic analysis using microsatellite markers revealed several cases of multiple paternity, both within nest and within clutch, indicating that some alternative male reproductive strategy, such as satellite behaviour is occurring. Larger males were observed to mate more frequently, and in multiple nests, suggesting that females are selecting for larger males, or that larger males are more capable of defending high quality territories. Males showed evidence of paternal care behaviours by remaining with the nests once females had left, moving throughout the nest cleaning, touching the eggs, and blowing bubbles into the centre of the doughnut-shaped egg masses. From this study I conclude that the male biased sexual size dimorphism in L. boringii is likely the result of both combat and paternal care behaviours creating a selection pressure on male body size.
1005

Comparative study of established test methods for aggregate strength and durability of Archean rocks from Botswana

Jessica, Stålheim January 2014 (has links)
ABSTRACT Comparative study of established test methods for aggregate strength and durabilityof Archean rocks from Botswana In the current situation, river sand is used for building of roads and as raw material forconcrete in Botswana. River sand is a finite resource and important to preserve as itacts as natural water purification, groundwater aquifer and protection against soil erosion.Mining of bedrock may be a good alternative to replace the river sand with crushed rock(aggregates) in concrete and as road materials.The main purpose of this thesis was to determine if the rock grain size can be usedas a parameter to indicate durability and rock strength. It was also of interest to find outif the grain size correlates with established technical analysis and strength test methods.This knowledge can be used as a prospecting tool when searching for new quarry sites inthe future.In this master’s thesis, rock samples from the Gaborone granite complex have beenanalysed to examine how established test methods and the mineral grain size correspondswith the rock strength. By comparing technical properties (Los Angeles (LA) value ,aggregate crushing value (ACV), aggregate impact value (AIV) and 10 percent fines aggregatecrushing test (10 % FACT)) with quantitative analysis (mineral grain size andmineral grain size distribution), it is possible to determine the mineral grain size correspondenceto rock strength. Generally the result show that more fine-grained granitesshow better technical properties than more coarse-grained granites. The calculated meangrain size show weak negative correlation to ACV value, and a positive correlation to LA-, AIV- and 10 % FACT values. Best correlation can be seen between mean grain size andLA values (R2= 0.61) and AIV values (R2= 0.58). Low mean grain size tend to give bettertechnical properties in form of lower LA- and AIV values. The cumulative distributioncurve show that a high concentration of very fine material or fine material tend to contributeto a lower LA value. The results indicate that equigranular rocks with low meangrain size contributes to good technical properties, but when it comes to uneven grainedrock more factors must be taken into account to estimate technical properties.
1006

GENETIC ANALYSIS OF IMPORTANT TRAITS FOR CONFECTIONERY SUNFLOWER IN AUSTRALIA

Yue Sun Unknown Date (has links)
Sunflower is grown worldwide for oil production. In Australia, sunflower is under intense competition from canola as an oil crop. Confectionery sunflower aimed for the overseas snack food market is a potential opportunity for Australian farmers due to its ability to provide off-season supply to the major market located mainly in the northern hemisphere. To serve this aim, new confectionery sunflower hybrids adapted to Australian production system with drought tolerance, large achenes, high self-fertility and rust resistance are of paramount importance. The objectives of this project were to understand the genetic inheritance and genetic linkage relationships of the above traits and also to identify linked DNA markers with the potential for marker-assisted selection (MAS). The inheritance of achene-length was studied in a 12 x 12 diallel and a 14 x 12 North Carolina design II (NC II) mating design. Achene-length was evaluated under three environments for each mating design. Genetic correlation among all five achene-size related traits (achene-length, -width, - thickness and also kernel-length and -width) and 100-achene weight were moderate to high. Narrow-and broad-sense heritability for achene-length was moderate to high and similar for each design. The general combining ability (GCA) and maternal effects were found to be the main genetic factors controlling achene-length and each accounted for around 45% of the total genotypic variance. The inheritance of self-fertility (SF) was assessed with the same 12 x 12 diallel mating design evaluated in two environments. The 12 parents also displayed various levels of SF in addition to a wide range of achene-length. Negative genetic correlations between SF and all five achene-size related traits and 100-achene weight were observed. Modelling achene-length as a covariate revealed that certain pre-pollination floret characteristics represented by achene-length at maturity strongly affects SF in sunflower. When the effect of achene-length was removed statistically as a covariate, the specific combining ability (SCA) effect increased dramatically and became the major factor (other than pre-pollination floret characteristics) for SF determination and accounted for 65% of the total variance. Long achene genotypes tended to have low SF and a positive SCA effect was observed more frequently in F1 hybrids that involved small achene lines. The broad sense heritability was moderate (0.663 ± 0.017), while the estimate of narrow-sense heritability was nearly zero. A segregating F6:7 recombinant inbred line population with 239 progeny was developed from a cross between HaR4, a low delta (Δ), high transpiration efficiency (TE), sunflower line with rust resistance but relatively low SF, and SA52 with all the characteristics in the opposite direction. The population was evaluated in two environments for three TE-related traits including Δ, specific leaf weight (SLW) and chlorophyll content (CC) and four agronomic traits i.e. days to flowering (DTF), plant height (PlantH), SF and rust resistance (RustR). A linkage map 1074.6 cM in length with 138 SSR and 37 ISSR markers consisting of 19 linkage groups was constructed. Spatially adjusted BLUPs were used in QTL analysis for individual and combined environments. Altogether, 10 QTL were identified for Δ, SLW and CC at individual environments, and 7 were detected by a combined analysis. Sixteen QTL were identified for 4 agronomic traits and 14 of them were confirmed by a combined analysis. Significant linkage among all three TE related traits was discovered on linkage group 4 (LG4), where alleles from one parent had the same direction of influence on TE which suggested either coupling phase linkage or pleiotropy. QTL for SF and RustR were closely linked on LG13. An F2 population with 502 progeny developed from a cross between Jumbo, a large achene confectionery sunflower line, and RIL25, an oilseed small achene line, was evaluated for five achene-size related traits in a single field trial. Using a subset of 178 progeny a framework genetic linkage map, 899.7 cM in length, containing 128 SSR markers and 23 ISSR markers was constructed with 18 linkage groups. Based on the results of a simulated QTL analysis, a modified selective genotyping strategy was employed for QTL analysis with 178 F2 individuals (128 randomly selected, 25 shortest achene F2’s and 25 longest achene F2’s). Altogether 18 achene-size related QTL with small effects were identified. Achene-size related genes characteristically expressed additive gene action although several alleles were partially recessive towards the large achene parent. The 18 identified achene-size related QTL were validated in the same diallel mating experiment mentioned above. Significant marker-trait associations were detected for 15 QTL. In addition to 12 significant alleles detected from the F2 population, 12 additional alleles associated with achene-size traits were revealed after the analysis with the diallel. These markers are ready to be used in MAS for confectionery sunflower breeding. Great steps have been made in obtaining essential knowledge of inheritance and linkage of target traits for breeding confectionery sunflower adapted to Australian production environments. The identified markers can be used in MAS and further enhance the breeding process.
1007

GENETIC ANALYSIS OF IMPORTANT TRAITS FOR CONFECTIONERY SUNFLOWER IN AUSTRALIA

Yue Sun Unknown Date (has links)
Sunflower is grown worldwide for oil production. In Australia, sunflower is under intense competition from canola as an oil crop. Confectionery sunflower aimed for the overseas snack food market is a potential opportunity for Australian farmers due to its ability to provide off-season supply to the major market located mainly in the northern hemisphere. To serve this aim, new confectionery sunflower hybrids adapted to Australian production system with drought tolerance, large achenes, high self-fertility and rust resistance are of paramount importance. The objectives of this project were to understand the genetic inheritance and genetic linkage relationships of the above traits and also to identify linked DNA markers with the potential for marker-assisted selection (MAS). The inheritance of achene-length was studied in a 12 x 12 diallel and a 14 x 12 North Carolina design II (NC II) mating design. Achene-length was evaluated under three environments for each mating design. Genetic correlation among all five achene-size related traits (achene-length, -width, - thickness and also kernel-length and -width) and 100-achene weight were moderate to high. Narrow-and broad-sense heritability for achene-length was moderate to high and similar for each design. The general combining ability (GCA) and maternal effects were found to be the main genetic factors controlling achene-length and each accounted for around 45% of the total genotypic variance. The inheritance of self-fertility (SF) was assessed with the same 12 x 12 diallel mating design evaluated in two environments. The 12 parents also displayed various levels of SF in addition to a wide range of achene-length. Negative genetic correlations between SF and all five achene-size related traits and 100-achene weight were observed. Modelling achene-length as a covariate revealed that certain pre-pollination floret characteristics represented by achene-length at maturity strongly affects SF in sunflower. When the effect of achene-length was removed statistically as a covariate, the specific combining ability (SCA) effect increased dramatically and became the major factor (other than pre-pollination floret characteristics) for SF determination and accounted for 65% of the total variance. Long achene genotypes tended to have low SF and a positive SCA effect was observed more frequently in F1 hybrids that involved small achene lines. The broad sense heritability was moderate (0.663 ± 0.017), while the estimate of narrow-sense heritability was nearly zero. A segregating F6:7 recombinant inbred line population with 239 progeny was developed from a cross between HaR4, a low delta (Δ), high transpiration efficiency (TE), sunflower line with rust resistance but relatively low SF, and SA52 with all the characteristics in the opposite direction. The population was evaluated in two environments for three TE-related traits including Δ, specific leaf weight (SLW) and chlorophyll content (CC) and four agronomic traits i.e. days to flowering (DTF), plant height (PlantH), SF and rust resistance (RustR). A linkage map 1074.6 cM in length with 138 SSR and 37 ISSR markers consisting of 19 linkage groups was constructed. Spatially adjusted BLUPs were used in QTL analysis for individual and combined environments. Altogether, 10 QTL were identified for Δ, SLW and CC at individual environments, and 7 were detected by a combined analysis. Sixteen QTL were identified for 4 agronomic traits and 14 of them were confirmed by a combined analysis. Significant linkage among all three TE related traits was discovered on linkage group 4 (LG4), where alleles from one parent had the same direction of influence on TE which suggested either coupling phase linkage or pleiotropy. QTL for SF and RustR were closely linked on LG13. An F2 population with 502 progeny developed from a cross between Jumbo, a large achene confectionery sunflower line, and RIL25, an oilseed small achene line, was evaluated for five achene-size related traits in a single field trial. Using a subset of 178 progeny a framework genetic linkage map, 899.7 cM in length, containing 128 SSR markers and 23 ISSR markers was constructed with 18 linkage groups. Based on the results of a simulated QTL analysis, a modified selective genotyping strategy was employed for QTL analysis with 178 F2 individuals (128 randomly selected, 25 shortest achene F2’s and 25 longest achene F2’s). Altogether 18 achene-size related QTL with small effects were identified. Achene-size related genes characteristically expressed additive gene action although several alleles were partially recessive towards the large achene parent. The 18 identified achene-size related QTL were validated in the same diallel mating experiment mentioned above. Significant marker-trait associations were detected for 15 QTL. In addition to 12 significant alleles detected from the F2 population, 12 additional alleles associated with achene-size traits were revealed after the analysis with the diallel. These markers are ready to be used in MAS for confectionery sunflower breeding. Great steps have been made in obtaining essential knowledge of inheritance and linkage of target traits for breeding confectionery sunflower adapted to Australian production environments. The identified markers can be used in MAS and further enhance the breeding process.
1008

Elternwünsche eine empirische Studie über Wünsche und Vorstellungen junger Eltern und daraus folgende Konsequenzen für Politik und Gesellschaft

Müller-Burhop, Mareike January 2006 (has links)
Zugl.: Oldenburg, Univ., Diss., 2006
1009

Dependência entre o tamanho da unidade básica e as estimativas das dimensões da parcela experimental de batata / Dependence between the size of basic unit and the estimations of potato experimental plot dimensions

Oliveira, Sérgio José Ribeiro de 11 November 2005 (has links)
Fundação de Amparo a Pesquisa do Estado da Bahia / A uniformity trail with potato was carried out at potato seed production area of FEPAGRO, Julio de Castilhos city, in 2003 agricultural year. Tuber yield of 3456 hills was evaluated with a set of basic units (BU) compound of 1; 2; 3; 4; 6; 8 and 12 hills per BU, in order to study the effect of size of BU about experimental plot dimensions, with width (W) and length (L) restricted to (W ≤ L). Soil heterogeneity index estimated to each BU and a heterogeneity contour map constructed to six hills per BU in the same row. Relationships between numbers of hills per BU and optimum plot size (X0) and correspondent area (S) were through three algebric methods: Meier & Lessman (1971), MO, and two methods related by Thomas (1974), MV and MC. Correlation analysis and path analysis allowed verify direct and indirect dependence among parameters that compound functions that represent each method analyzed and m2. The results showed that same number of hills per BU, MO demanded more area and presented results coherent with practices applications than MV and MC that presented values of S minor that equivalent to one hill, not feasible to application of treatments. As the magnitude of origin as magnitude of curve were determinative of X0. The area demand occurs more intensely as from four hills per BU. The MC method was least responsive to changes. The soil presented more homogeneity within rows, indication of plot orientation in area such as plot shape, narrow and length in the same row. / Foi instalado um ensaio de uniformidade com batata, na área de produção de tubérculos de batata-semente da FEPAGRO, em Júlio de Castilhos, RS, no ano agrícola de 2003. Foi avaliado o rendimento de tubérculos de batata de 3456 covas, que foram constituídos, inicialmente, de uma unidade básica (UB). Foram planejadas, ainda, parcelas compostas de 2; 3; 4; 6; 8 e 12 covas por UB, com o objetivo de estudar o efeito do tamanho da UB nas dimensões das parcelas experimentais. Aplicou-se uma restrição entre os comprimentos (C) e larguras (L) selecionadas (L ≤ C). Foram estimados índices de heterogeneidade do solo para cada tamanho de UB e representado um mapa de heterogeneidade para UB compostas de seis covas numa mesma fila. Obtiveram-se relações entre tamanho ótimo de parcela (X0), área correspondente (S) e os diversos números de covas por UB, por três métodos algébricos: o método descrito por Meier & Lessman (1971), MO, e dois métodos descritos por Thomas (1974), MV e MC. Além da análise de correlação verificou-se também a ocorrência de dependência direta e indireta entre os parâmetros que compõem as funções que representam cada método estudado e a área correspondente. Os resultados obtidos demonstraram que para um mesmo número de covas por UB, o método MO demandou mais área e apresentou resultados mais coerentes com aplicações práticas que MV e MC, que apresentaram valores de área inferiores a uma cova, incompatível à aplicação de tratamentos. Tanto a magnitude da origem quanto a da curva foram determinantes de X0. A demanda por área ocorreu mais intensamente a partir de quatro covas por UB, sendo o método MC o que menos respondeu às variações. O solo apresentou-se mais homogêneo dentro das filas, o que orientou a direção das parcelas na área, assim como a forma, devendo ter maior comprimento que largura.
1010

Detecção de outliers baseada em caminhada determinística do turista / Outlier detection based on deterministic tourist walk

Rafael Delalibera Rodrigues 03 April 2018 (has links)
Detecção de outliers é uma tarefa fundamental para descoberta de conhecimento em mineração de dados. Cujo objetivo é identificar as amostras de dados que desviam acentuadamente dos padrões apresentados num conjunto de dados. Neste trabalho, apresentamos uma nova técnica de detecção de outliers baseada em caminhada determinística do turista. Especificamente um caminhante é iniciado para cada exemplar de dado, variando-se o tamanho da memória, assim, um exemplar recebe uma alta pontuação de outlier ao participar em poucos atratores, enquanto que receberá uma baixa pontuação no caso de participar numa grande quantidade de atratores. Os resultados experimentais em cenários artificiais e reais evidenciaram um bom desempenho do método proposto. Em comparação com os métodos clássicos, o método proposto apresenta as seguintes características salientes: 1) Identifica os outliers através da determinação de estruturas no espaço de dados ao invés de considerar apenas características físicas, como distância, similaridade e densidade. 2) É capaz de detectar outliers internos, situados em regiões entre dois ou mais agrupamentos. 3) Com a variação do valor de memória, os caminhantes conseguem extrair tanto características locais, quanto globais do conjunto de dados. 4) O método proposto é determinístico, não exigindo diversas execuções (em contraste às técnicas estocásticas). Além disso, neste trabalho caracterizamos, pela primeira vez, que as dinâmicas exibidas pela caminhada do turista podem gerar atratores complexos, com diversos cruzamentos. Sendo que estes podem revelar estruturas ainda mais detalhadas e consequentemente melhorar a detecção dos outliers. / Outlier detection is a fundamental task for knowledge discovery in data mining. It aims to detect data items that deviate from the general pattern of a given data set. In this work, we present a new outlier detection technique using tourist walks. Specifically, starting from each data sample and varying the memory size, a data sample gets a higher outlier score if it participates in few tourist walk attractors, while it gets a low score if it participates in a large number of attractors. Experimental results on artificial and real data sets show good performance of the proposed method. In comparison to classical methods, the proposed one shows the following salient features: 1) It finds out outliers by identifying the structure of the input data set instead of considering only physical features, such as distance, similarity or density. 2) It can detect not only external outliers as classical methods do, but also internal outliers staying among various normal data groups. 3) By varying the memory size, the tourist walks can characterize both local and global structures of the data set. 4) The proposed method is a deterministic technique. Therefore, only one run is sufficient, in contrast to stochastic techniques, which require many runs. Moreover, in this work, we find, for the first time, that tourist walks can generate complex attractors in various crossing shapes. Such complex attractors reveal data structures in more details. Consequently, it can improve the outlier detection.

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