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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.
361

Relative Importance of Male Song on Female Mate Selection in the Zebra Finch (Taeniopygia Guttata)

Sprague, Casey 01 January 2014 (has links)
In the zebra finch (Taeniopygia guttata), song and its social context play an important role in female mate selection. The song of the zebra finch is unique in that it can only be produced by males, which makes the species ideal for analyzing the components of male song that influence female song preference and mate selection. There are three consistent features of zebra finch song that affect female mate preference: 1) the amount of time a male sings, 2) the size and complexity of his song repertoire, and 3) the structural conformation to species or population norms (reviewed in Nowicki et al. 2002). During courtship, male zebra finches often express ‘static-visual’ and ‘dynamic-visual’ elements in sync with song (Morris 1954), which would suggest that such behaviors also play a role in influencing female mate preference. However, with courtship comes the competition between males for the attention of potential mates. These agonistic interactions between males act settle disputes over access to mates, and as such, are also likely to influence female mate selection. As follows, we predict that, at the initial onset of courtship, there would be a higher prevalence of male-to-female courting interactions and singing behavior in comparison to male-to-male agonistic tendencies if female mate selection is fundamentally determined by song preference. However if female mate selection is more complicated than simple song preference, we would expect to initially observe a higher number of agonistic interactions between males as they compete for dominance. This hypothesis was tested by recording and analyzing the behavioral interactions between male and female zebra finches in the context of song complexity. We found that different males scored higher for song complexity than those for expression of courtship behaviors, which indicates that different elements of male courtship display likely influence female mate preference. Our data comparing male-to-male interactions and male-to-female interactions within the first 30 minutes after introduction was statistically insignificant, suggesting that female mate selection is more complicated than simple song preference. This preliminary research can be used as a basis for future studies using quantitative movement tracking analysis, which would further strengthen these initial observations. By increasing our understanding of the influence the male song has on female mate selection, we can better expound upon the nature and function of the favored traits that male songbirds possess and the benefits that females and their progeny might gain from choosing a male with these particular attributes.
362

The Role of Acculturation on Bosnian Refugee Adult Child Mate Selection

Herovic, Emina 01 January 2013 (has links)
Forced by the atrocities of war from their native country, Bosnian families came to United States seeking refuge and a new life. Immigrating to a new country, however, involves the process of acculturation which can dilute many native practices. Like many refugees that immigrated, Bosnians sought to adapt to the American way of life, while keeping their traditional ethnic customs, practices, and religion (Val & Iain-Walker, 2003). Many Bosnian refugee parents worked to keep the Bosnian practices prevalent in their first and second generation Bosnian American children. By doing so, Bosnian parents imbedded into their children the original customs, practices, and traditions of the Bosnian culture. Moreover, they raised their children to have great pride in their native country. Part of keeping the native culture alive, as an adult child of a refugee, involved marrying someone of the same ethnic and religious background (Inman, Howard, Beaumont, &Walker, 2007). Using Communication Acculturation Theory, this study examined the relationship between the degree of acculturation of Bosnian refugees in the United States and their preference and stress level in relational partner selection taking into consideration parental pressure and ethnic group community expectations. Results from this study find that acculturation is negatively correlated with the preference for a Bosnian mate but only the amount of interpersonal intimate communication the Bosnian members has with Bosnians and non-Bosnians is indicative of any mate selection stress experienced. Further, ethnic group community expectations and parental pressure are positively correlated with preference for a Bosnian mate, but only the expectations of the ethnic group and not pressure from parents was correlated with any stress the individual feels to find a Bosnian mate.
363

Sistemas de vehiculización de antioxidantes naturales y minerales

López Córdoba, Alex Fernando January 2014 (has links)
Las nuevas tendencias en el sector de alimentos incluyen la obtención de productos que, además de ser fuente de macronutrientes, aporten compuestos bioactivos que prevengan la aparición de enfermedades crónicas; siendo cada vez más importante satisfacer las necesidades específicas de poblaciones de individuos, ya sea en estado saludable o con una enfermedad particular. El objetivo del presente trabajo fue desarrollar sistemas de vehiculización para el transporte individual o simultáneo de antioxidantes naturales y minerales. Se obtuvieron polvos conteniendo zinc, extracto de yerba mate o una combinación de ambos, mediante la técnica de co-cristalización en matrices de sacarosa. En general, los productos obtenidos mostraron buena fluidez y bajos valores de contenido de humedad, actividad acuosa e higroscopicidad. Además, los compuestos activos encapsulados mostraron una buena estabilidad fisicoquímica durante el almacenamiento. Se prepararon bebidas con antioxidantes naturales usando como ingrediente los polvos con extracto de yerba mate. Estas fueron evaluadas sensorialmente por un panel de jueces no entrenados, encontrando elevados niveles de aceptación. Por otro lado, se prepararon tabletas mediante compresión directa, mezclando los compuestos activos encapsulados (zinc, extracto de yerba mate o una combinación de ambos) con excipientes (almidón de maíz y estearato de magnesio). Todas las formulaciones mostraron óptimas características de manipuleo (fluidez y humedad) y buena compactibilidad. Se evaluaron los atributos sensoriales de las tabletas obteniendo una buena aceptabilidad. Finalmente, se desarrollaron tabletas compartimentalizadas para co-vehiculización de zinc y extracto de yerba mate. Estas matrices permitieron mantener las propiedades individuales de cada compuesto activo. Para la compartimentalización, el almidón de maíz nativo fue usado como un vehículo de zinc. Las tabletas obtenidas se desintegraron rápidamente y mostraron una alta velocidad de liberación de los compuestos activos en agua. Los sistemas desarrollados para la vehiculización de minerales y antioxidantes naturales constituyen una alternativa para aumentar la ingesta dietaría de estos compuestos bioactivos con propiedades saludables.
364

New Insights into the Evolutionary Mantenance of Male Mate Choice Behaviour using the Western Black Widow Spider, Latrodectus hesperus

MacLeod, Emily 08 August 2013 (has links)
Mate choice among males is relatively understudied, despite recent evidence supporting its ubiquity. Theory predicts male mate choice in response to variation in female quality, and male mating strategies that limit polygyny. However empirical research investigating these connections, particularly under natural conditions, is generally lacking. Using the Western black widow spider, Latrodectus hesperus, I investigated male mate choice, male investment, and the advantage of mating with females that differ in their potential to deliver fitness benefits to males via higher fecundity and/or reduced risk of sperm competition. Males were found to be preferentially attracted to larger, high-diet virgin females over females that were smaller due to a lower diet, or having been previously mated, or both. Through a three-year field study on females I found that males likely benefit from selectivity, as smaller, low-diet females often failed to deposit any egg sacs throughout the breeding season, likely due to their shortened web-site tenure and/or lack of bodily resources. I investigated the costs and benefits to male genital breakage in L. hesperus, a strategy typically assumed to result in male sterility while providing paternity protection. I found that genital mutilation in L. hesperus did not cause sterility and that males were capable of inseminating multiple females, likely because of the comparatively low amount of genital damage and the likelihood of the efficient placement of genital fragments. Evidence from double mating trials supported the efficacy of broken genital fragments as plugs, but first male sperm precedence was often maintained in cases where male genital breakage failed or fragments were positioned incorrectly, which occurred frequently. Together, these laboratory and field experiments contribute to a more complete view of mate choice.
365

New Insights into the Evolutionary Mantenance of Male Mate Choice Behaviour using the Western Black Widow Spider, Latrodectus hesperus

MacLeod, Emily 08 August 2013 (has links)
Mate choice among males is relatively understudied, despite recent evidence supporting its ubiquity. Theory predicts male mate choice in response to variation in female quality, and male mating strategies that limit polygyny. However empirical research investigating these connections, particularly under natural conditions, is generally lacking. Using the Western black widow spider, Latrodectus hesperus, I investigated male mate choice, male investment, and the advantage of mating with females that differ in their potential to deliver fitness benefits to males via higher fecundity and/or reduced risk of sperm competition. Males were found to be preferentially attracted to larger, high-diet virgin females over females that were smaller due to a lower diet, or having been previously mated, or both. Through a three-year field study on females I found that males likely benefit from selectivity, as smaller, low-diet females often failed to deposit any egg sacs throughout the breeding season, likely due to their shortened web-site tenure and/or lack of bodily resources. I investigated the costs and benefits to male genital breakage in L. hesperus, a strategy typically assumed to result in male sterility while providing paternity protection. I found that genital mutilation in L. hesperus did not cause sterility and that males were capable of inseminating multiple females, likely because of the comparatively low amount of genital damage and the likelihood of the efficient placement of genital fragments. Evidence from double mating trials supported the efficacy of broken genital fragments as plugs, but first male sperm precedence was often maintained in cases where male genital breakage failed or fragments were positioned incorrectly, which occurred frequently. Together, these laboratory and field experiments contribute to a more complete view of mate choice.
366

Early-rearing Environment and Mate Choice in Chinook Salmon (Oncorhynchus tshawytscha) Aquaculture: Effects on the Immune System

Becker, Leandro Anibal January 2011 (has links)
Canada is the fourth largest producer of farmed salmon in the world, with Atlantic salmon being the major species cultivated. Paradoxically British Columbia (BC), which borders the Pacific Ocean, is the major producer province where Atlantic salmon was introduced in the mid-80’s. Escaped salmon may constitute a threat to natural populations of Pacific salmon as they compete for the same resources such as food and spawning territory. A potential solution to the aquaculture industry would be to further develop the aquaculture of native species in the region. The work presented here used semi-natural spawning channels to evaluate the effects of breeding strategies and early-rearing environments on the immune performance of Chinook salmon. Breeding strategy was tested analyzing artificial hatchery practices versus semi-natural propagation in spawning channels. Early-rearing environmental assessment contrasted indoor plastic hatchery tanks with outdoor gravelled-bottom spawning channels. A disease challenge involving over 1400 fish showed interaction effects between breeding strategy and rearing environment. Fish artificially mated presented a disease susceptibility influenced by the rearing environment. The contrary occurred in the offspring of self-breeding brood stock in the spawning channels, as no differences were observed in their susceptibility to the disease regardless of rearing environment. Monitoring of anti-Vibrio anguillarum antibodies during the disease challenge and a follow up of the survivors in sea net pens further confirmed the interaction between breeding strategy and rearing environment. Gene expression in pre- and post-infected artificially propagated fish showed differential gene expression when analyzed with a 695-gene cDNA microarray for Chinook salmon. Genotyping of major histocompatibility (MH) class II β1 alleles showed a tendency of a higher heterozygosity in survivors as expected, as well as a general tendency of a higher heterozygosity in semi-naturally propagated fish. The latter is likely a direct consequence of MH-linked mate choice, which was recently described in Chinook salmon (Neff et al., 2008). To further characterize the mating system of Chinook salmon in the spawning channels, brood stock were genotyped at 12 microsatellite loci. Females and males were found to mate randomly with regards to genetic pairwise relatedness, but they tended to mate with fish of similar condition as revealed by their pairwise differences in Fulton’s condition factor. This work demonstrated that genotype-by-environment interactions can modify the disease resistance of Chinook salmon. More importantly, these effects were seen after just one round of semi-natural spawning of domesticated hatchery fish, suggesting that further studies on spawning channels may highlight other hidden benefits. Therefore, breeding strategy and early-rearing environment should be considered when propagating cultured stocks. The use of more natural propagation methods such as spawning channels could improve the immune performance of Chinook salmon and help to expand the aquaculture of this native species in BC.
367

Can't buy me love or can I? : the influence of power, attitudes, and attractiveness on women's romantic partner preferences

Le, Yen-Chi Lam January 2008 (has links)
Thesis (Ph.D.)--University of Hawaii at Manoa, 2008. / In recent years, more studies are exploring how contextual factors may influence mate preferences. Based on social learning theory, power, attitudes towards egalitarian gender roles, and type of mating were expected to influence women's romantic preferences for physical attractiveness and for resources. An online questionnaire was administered to a community sample and data analyses were employed using structural equation modeling (SEM) and multivariate analyses of variance (MANOVA). Results showed that, as women's power increased, women showed increased preferences for physical attractiveness and sexiness in potential short-term mates and increased preference for intelligence in potential long-term mates. Power and attitudes were also found to be significant in predicting women's preferences for physical attractiveness relative to potential earning capacity in both short-term and long-term mating conditions. / Includes bibliographical references (leaves 85-92). / Also available by subscription via World Wide Web / 92 leaves, bound 29 cm
368

The ecstatic display call of the Adélie penguin (Pygoscelis adeliae)

Marks, Emma Josephine January 2009 (has links)
The ability to understand the complex mechanisms by which species communicate has been the focus of study for many years. The Adélie penguin (Pygoscelis adeliae) breeds in vocally challenging Antarctic colonies and has evolved a complex system of intra- and intersexual visual and vocal behaviours. Unique to the Adélie penguin, is the presence of two distinct display calls, the Loud Mutual Display (LMD) call and male Ecstatic Display Call (EDC). The EDC is used for both mate choice and territory defence; but apart from general structure and function this call remains basically unstudied. Therefore, the aim of this study is to examine the EDC with regard to its function (during mate choice) and variability over time, with location and with changing conditions. It is predicted that the EDC will be an individual call that is distinct from the LMD call. Additionally, the effects of an inclement breeding season on factors that affect breeding success will be examined using a logistic regression approach. The study took place over two breeding seasons(2000/1 & 2002/3) on Ross Island, Antarctica, with the majority of research being conducted at Cape Bird. Results of the study indicate that the EDC is an individual call that cannot reliably be described as a male display as females also give an EDC that is acoustically comparable. The similarities between the EDC and the LMD call seem to relate only to syllabic organisation (structure), as almost every call parameter was different between call types. Furthermore, several call parameters differed between Ross Island colonies. These parameters varied with both geographical location and colony size. In conjunction with variation in call parameters, the health and breeding success of the colonies was different. The stability of call parameters (from Cape Bird) indicated that parameters that separate colonies not only alter between breeding years, but also vary during a single breeding season. The function of the EDC as an honest signal during mate choice was supported by spectral analyses. These analyses found heavier males had significantly lower Frequency Modulation (FM) in the short repeated syllables of their calls than lighter males. Furthermore, a male’s breeding success could be predicted during the early breeding season by the FM. Logistic regression models showed that early male arrival, weight and good nest quality were most influential in predicting fledging success. The logistic regression method also showed that the parameters measured varied in their predictive ability as the season progressed. This study has not only enhanced the wealth of knowledge regarding Adélie breeding behaviour and developed our understanding of the vocal repertoire of this species, but also has implications for honest signalling theory, and the evolution and stability of vocal variation at different spatial and temporal scales.
369

The ecstatic display call of the Adélie penguin (Pygoscelis adeliae)

Marks, Emma Josephine January 2009 (has links)
The ability to understand the complex mechanisms by which species communicate has been the focus of study for many years. The Adélie penguin (Pygoscelis adeliae) breeds in vocally challenging Antarctic colonies and has evolved a complex system of intra- and intersexual visual and vocal behaviours. Unique to the Adélie penguin, is the presence of two distinct display calls, the Loud Mutual Display (LMD) call and male Ecstatic Display Call (EDC). The EDC is used for both mate choice and territory defence; but apart from general structure and function this call remains basically unstudied. Therefore, the aim of this study is to examine the EDC with regard to its function (during mate choice) and variability over time, with location and with changing conditions. It is predicted that the EDC will be an individual call that is distinct from the LMD call. Additionally, the effects of an inclement breeding season on factors that affect breeding success will be examined using a logistic regression approach. The study took place over two breeding seasons(2000/1 & 2002/3) on Ross Island, Antarctica, with the majority of research being conducted at Cape Bird. Results of the study indicate that the EDC is an individual call that cannot reliably be described as a male display as females also give an EDC that is acoustically comparable. The similarities between the EDC and the LMD call seem to relate only to syllabic organisation (structure), as almost every call parameter was different between call types. Furthermore, several call parameters differed between Ross Island colonies. These parameters varied with both geographical location and colony size. In conjunction with variation in call parameters, the health and breeding success of the colonies was different. The stability of call parameters (from Cape Bird) indicated that parameters that separate colonies not only alter between breeding years, but also vary during a single breeding season. The function of the EDC as an honest signal during mate choice was supported by spectral analyses. These analyses found heavier males had significantly lower Frequency Modulation (FM) in the short repeated syllables of their calls than lighter males. Furthermore, a male’s breeding success could be predicted during the early breeding season by the FM. Logistic regression models showed that early male arrival, weight and good nest quality were most influential in predicting fledging success. The logistic regression method also showed that the parameters measured varied in their predictive ability as the season progressed. This study has not only enhanced the wealth of knowledge regarding Adélie breeding behaviour and developed our understanding of the vocal repertoire of this species, but also has implications for honest signalling theory, and the evolution and stability of vocal variation at different spatial and temporal scales.
370

The ecstatic display call of the Adélie penguin (Pygoscelis adeliae)

Marks, Emma Josephine January 2009 (has links)
The ability to understand the complex mechanisms by which species communicate has been the focus of study for many years. The Adélie penguin (Pygoscelis adeliae) breeds in vocally challenging Antarctic colonies and has evolved a complex system of intra- and intersexual visual and vocal behaviours. Unique to the Adélie penguin, is the presence of two distinct display calls, the Loud Mutual Display (LMD) call and male Ecstatic Display Call (EDC). The EDC is used for both mate choice and territory defence; but apart from general structure and function this call remains basically unstudied. Therefore, the aim of this study is to examine the EDC with regard to its function (during mate choice) and variability over time, with location and with changing conditions. It is predicted that the EDC will be an individual call that is distinct from the LMD call. Additionally, the effects of an inclement breeding season on factors that affect breeding success will be examined using a logistic regression approach. The study took place over two breeding seasons(2000/1 & 2002/3) on Ross Island, Antarctica, with the majority of research being conducted at Cape Bird. Results of the study indicate that the EDC is an individual call that cannot reliably be described as a male display as females also give an EDC that is acoustically comparable. The similarities between the EDC and the LMD call seem to relate only to syllabic organisation (structure), as almost every call parameter was different between call types. Furthermore, several call parameters differed between Ross Island colonies. These parameters varied with both geographical location and colony size. In conjunction with variation in call parameters, the health and breeding success of the colonies was different. The stability of call parameters (from Cape Bird) indicated that parameters that separate colonies not only alter between breeding years, but also vary during a single breeding season. The function of the EDC as an honest signal during mate choice was supported by spectral analyses. These analyses found heavier males had significantly lower Frequency Modulation (FM) in the short repeated syllables of their calls than lighter males. Furthermore, a male’s breeding success could be predicted during the early breeding season by the FM. Logistic regression models showed that early male arrival, weight and good nest quality were most influential in predicting fledging success. The logistic regression method also showed that the parameters measured varied in their predictive ability as the season progressed. This study has not only enhanced the wealth of knowledge regarding Adélie breeding behaviour and developed our understanding of the vocal repertoire of this species, but also has implications for honest signalling theory, and the evolution and stability of vocal variation at different spatial and temporal scales.

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