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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.

Sex ratio theory in a splash pool : the sex ratio trait of Tigriopus californicus

Voordouw, Maarten Jeroen. 10 April 2008 (has links)
Sex ratio theory makes predictions about how sexually reproducing organisms should allocate their reproductive efforts towards sons and daughters. Fisher predicted that the optimal strategy is one of equal investment (i.e. the 50:50 sex ratio). Subsequent analysis has shown that Fisher's equilibrium sex ratio is contingent on a number of assumptions such as autosomal inheritance of sex ratio alleles, large population size, additive offspring costs, etc. When any of these assumptions are violated the equilibrium sex ratio is not necessarily the one predicted by Fisher. To test sex ratio theory requires systems that exhibit variation for the primary sex ratio. The harpacticoid copepod, Tigriopus californicus is one such system. I have repeatedly detected a large, extra-binomial variance component in the primary sex ratio among full sib families in several natural populations on Vancouver Island. Environmental factors such as temperature and larval density have a mild effect on the primary sex ratio but are not likely to drive sex ratio variation at the population level. Cytoplasmic sex ratio distorters such as Wolbachia are known to cause sex ratio fluctuations in the populations of other crustaceans but were not detected in T. californicus. In the absence of sex-biased mortality, lineage analysis revealed that the sex ratio trait in a local population of T. calijornicus was paternally transmitted. Uniparentally transmitted sex ratio factors are generally under strong selection to increase the proportion of the transmitting sex in their host population. This observation may provide an explanation as to why the population-wide primary sex ratio in T. californicus and other harpacticoid copepods is often male-biased.

The relation of antecedent egg production to the sex ratio of the domestic fowl

Jull, Morley A. January 1924 (has links)
Presented as Thesis (Ph. D.)--University of Wisconsin--Madison, 1923. / Cover title. Reprinted from Journal of agricultural research, vol. XXVIII, no. 3 (19 Apr. 1924). Contribution from Bureau of Animal Industry (A-77). "The experimental part of the work was conducted in the Dept. of Genetics, Agricultural Experiment Station, University of Wisconsin, and at Macdonald College, St. Anne d'Bellevue, P.Q. Canada ... Pub. with the approval of the director of the Wisconsin Station as paper no. 46." "Literature cited": p. 221-224.

The sex ratio in mules and other hybrid mammals

Craft, William Arthur. January 1932 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1932. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves [38]-45).

Effects of resource availability on sex allocation in herbivores

Johnstone-Yellin, Tamara Lee, January 2010 (has links) (PDF)
Thesis (Ph. D.)--Washington State University, May 2010. / Title from PDF title page (viewed on July 15, 2010). "Department of Natural Resource Sciences." Includes bibliographical references.

Sex ratio in sheep

Henning, W. L. January 1937 (has links)
Thesis (Ph. D.)--University of Wisconsin--Madison, 1937. / Typescript. Includes abstract and vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaves 37-40).

Contrôle royal du sex-ratio chez les fourmis: approche methodologique et expérimentale

de Menten de Horne, Ludivine January 2005 (has links)
Doctorat en Sciences / info:eu-repo/semantics/nonPublished

The Sex Ratio Tipping Point: An Exploration of Crime during Frontier America

Stearmer, Steven Matthew 10 August 2011 (has links) (PDF)
Prior research confirms that the number of men in a population is associated with elevated levels of crime. The connection between higher numbers of males relative to females and crime is far less studied in larger aggregate populations, and the nature of the relationship is less clear. This study seeks to answer three questions: are unbalanced sex ratios associated with crime at the state level? At what level does the skew begin to matter? How quickly is the impact observed? These questions are examined through analysis of a novel longitudinal dataset of social characteristics and crime indicators for frontier American states between 1850 and 1920. Fixed effects longitudinal analysis reveals a positive association at the state level between skewed sex ratios - towards both men and women - and crime. This study concludes that any deviation from an equal sex ratio is associated with higher levels in crime, and this impact was demonstrated to occur within a short time frame.

Environmental influences on sex ratio and spatial distribution of dioecious Morella cerifera L. on a Virginia barrier island.

Hokkanen, Molly 05 August 2013 (has links)
For dioecious plant species, sex ratios within a population depend on multiple environmental and life history characteristics. Sex ratio is an indicator of population health and can be a predictor for genetic bottlenecking. My study established the previously unknown sex ratio for the shrub, Morella cerifera, on a Virginia barrier island. The ratio was compared with multiple environmental and reproductive traits to determine their potential influence on sex determination and/or distribution of male and female plants. Multivariate analyses were used to identify relationships between sex, sex ratio and environmental drivers. The sex ratio for M. cerifera changed depending on scale. The entire island ratio did not vary significantly from 50:50, based on a Chi-squared analysis. Different spatial scales resulted in different and more variable sex ratios. The environmental variables measured did not suggest any relationships with sex or sex ratio. Future studies with a focus at multiple spatial scales may elucidate the connection between environment and sex ratios for M. cerifera.

Modernization and women's status in India : a gender in development perspective on dowry deaths, sex ratios, and sex-selective abortions /

Mandal, Shipra, January 2000 (has links)
Thesis (Ph. D.)--University of Texas at Austin, 2000. / Vita. Includes bibliographical references (leaves 296-317). Available also in a digital version from Dissertation Abstracts.

The sex ratio and multiple births in cattle

Johansson, Ivar, January 1900 (has links)
Presented as Thesis (Ph. D.)--University of Wisconsin--Madison, 1930. / Cover title. Reprinted from Zeitschrift für Züchtung. Reihe B Tierzüchtung und Züchtungsbiologie einschliesslich Tierernährung, Band XXIV, Heft 2. Includes bibliographical references (leaves 264-268).

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