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Thesis (Ph.D.)--City University of New York, 2005. / Adviser: Virginia Held. Includes bibliographical references.

Inaug.-Diss.--Heidelberg. / Lebenslauf. "Benutzte literatur": p. [21]-22.

Thesis (Ph. D.)--University of Michigan, 1998. / Includes bibliographical references (leaves 122-137).

Thèse--Université de Strasbourg. / "Index bibliographique": p. 483-497.

Inaug.-diss.--Bonn. / Lebenslauf. "Literaturangabe": p. [28]-29.

Inaug.-diss.--Göttingen. / Lebenslauf. "Verzeichnis der benutzten literatur": p. 26-27.

Chum salmon embryonal discs were smeared and the cells stained with acetocarmine (60° C.) for chromosome content. Thirty-eight chromosomes (granular, sigmoid, and j-shaped) were counted, but the number was not considered absolute. The presence of sex chromosomes could not be established. Chromosomes in cells of differentiating gonads showed such excessive clumping that a count could not be made. Sex differentiation was followed in chum salmon. Sections from alevins (three weeks old) showed the gonads to be indifferent. Isolated nests of germ cells appeared which eventually formed a continuous cord (five weeks). At nine weeks the primordial ovary developed oocytes and in the succeeding week formed an endovarial canal. At this time the testis was first recognized (ten weeks). It was a small compact organ containing spermatogonia. Up to the final examination (fifteen weeks) the ovary showed no new structures excepting a prominent vena commites anteriad, while the testis retained its primitive features. The sex of pink and chum salmon fry migrants were shown by dissection. Ultraviolet light and temperature treatment of developing chum, pink, and sockeye embryos did not show that these factors would influence the sex ratio. Temperature data were decidedly inconclusive. An equal distribution of the sexes in pink and chum fry and sockeye smolts was found in data compiled from migrant runs at Port John, B. C. It is suggested that precocious male sockeye mature in the sea. The sex ratios at stages in the life history of the pink salmon are presented to show that there had occurred a natural sea mortality of 40.2 percent. / Science, Faculty of / Zoology, Department of / Graduate

This dissertation consists of three essays on Health Economics. Chapter 1 analyzes the effects of abortion costs for minors on abortions, sexual behavior, and births. We exploit a 2015 change in parental involvement (PI) laws in Spain as a natural experiment in costs, together with rich population-level data on abortions and births. Using the exact date of teenager birth, we first document a decrease in abortions by 17-years-olds using a difference-in-difference comparison with 18-years-olds, consistent with the law that targeted Spanish minors. Using bunching methods from the Public Finance literature, we show evidence of temporal displacement. Some 17-years-old delayed their abortion and waited until they turned 18 and thereby avoided involving their parents. Second, we consider how the law change may have influenced health-related behaviors, finding implicitly that sexual behaviors changed so as to reduce the likelihood of becoming pregnant before turning 18 (and thereby internalized the cost of parental involvement). This is seen in the permanent shift in the number of abortions at age 18 that exists after removing the temporal displacement abortions around the age 18 threshold and an increase in the number of births to mothers who were pregnant at age 17. This paper finds that an important dimension of risky youth behavior responds to incentives contained in parental notification laws. Chapter 2 analyzes the effects of abortion costs on sex-selection by exploiting a 2010 abortion liberalization in Spain and the difference in son-preferences by nationality and child order documented in the literature. We show using a difference-in-difference comparison a significant increase in the fraction of boys for Chinese parents giving birth to their third child or above relative to children born of Spanish parents. Consistent with the literature, we do not find any effect on the fraction of boys for the first or the second child. Using the provincial number of abortion centers per person as a measure of access to abortion, we show, at the correlation level, that the effects come from those provinces with higher access to abortions. Finally, we find suggestive evidence that birth outcomes of Chinese girls who are the third children, and thus are now more likely to be ``wanted'' after the reform, improve. Gestational weeks increase, and the chance of being born prematurely decrease although our evidence suffers from lack of power. Finally, chapter 3 analyzes the effects of a universal, unconditional cash transfer announcement on birth outcomes by exploiting the 2007 cheque bebé policy in Spain that provided 2,500 euros per child to all mothers giving birth immediately after its announcement (Jul 2007). We use a difference-in-difference analysis comparing those born before and after the announcement. By exploiting the timing of the policy announcement we can avoid the composition effects caused by the incentives to have children generated by the policy. We show that the birth weight of those children born after the policy announcement (Sept-Dec) significantly improved relative to those born before (Apr-Jun) using previous years to control for the seasonal effects. Moreover, we provide suggestive evidence that those who are more vulnerable, as measured by the average municipality income level, parents' marital status, or parents' age, experience the most substantial improvements on birth weight.

Made available in DSpace on 2016-08-12T18:48:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2015-04-08. Added 1 bitstream(s) on 2016-08-12T18:50:57Z : No. of bitstreams: 1 000865637.pdf: 1293456 bytes, checksum: d01165e048932b40382e97a518db2fc9 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A Tilápia do Nilo é uma espécie de grande relevância na aqüicultura mundial. Espécimes do sexo masculino têm maior crescimento quando comparado as fêmeas, uma característica importante em sistemas de produção de peixe. Infelizmente, os mecanismos envolvidos no desenvolvimento que levam à diferenciação sexual em peixes ainda são pouco compreendidos. Vários genes e miRNAs tem sido propostos como influênciadores desses processos, porém seu efetivo papel, permanece desconhecido. Considerando a importância biológica do desenvolvimento embrionário e determinação do sexo, microRNomas de tilápia do Nilo, expressos durante o desenvolvimento e em indivíduos machos e fêmeas adultos, foram analisados. Bibliotecas de pequenos RNAs foram geradas a partir de embriões de 3 e 5 dias pós fertilização (dpf), e cérebro e gônadas de indivíduos adultos de ambos os sexos, e seqüenciados via plataforma Illumina. Foram identificados 194 miRNAs já conhecidos com base em bancos de dados referência de zebrafish, sendo que destes 120 apresentaram expressão diferencial entre macho e fêmea de O. niloticus. Foram identificados ainda 74 novos miRNAs não presentes no banco de dados referência. Vinte e dois miRNAs foram testados por qPCR e cinco tiveram seus genes-alvo candidatos testados pelo ensaio de gene repórter da luciferase. Os resultados de qPCR mostraram que a expressão da família do miR-10 foi alta durante os períodos de 3 e 5dpf. Softwares de predição sugerem que essa família de miRNAs regula a expressão de membros dos genes Hox. Sendo assim, foram testados por qPCR e pelo ensaio do gene réporter da luciferase três genes dessa família: HoxA3a, HoxB3a e HoxD10a. Os resultados mostraram que miR-10b tem como alvos Hoxb3a e HoxD10a. Já na diferenciação do sexo, os resultados de qPCR apontaram uma alta expressão do miR-145-5p durante o desenvolvimento de embriões de fêmea, enquanto seu possível alvo, Sox9a, teve... / The Nile tilapia is a species of great importance in world aquaculture. Male specimens have increased growth compared with females, an important feature in fish production systems. Unfortunately, the mechanisms involved in the development and sexual differentiation in fish are still poorly understood. Several genes and miRNAs have been reported as influencing these processes, but its effective role remains unknown. Given the biological importance of miRNAs to embryonic development and sex determination, microRNomes were analyzed during development and in adult male and female of O. niloticus. Small RNAs libraries were generated from 3 and 5 dpf embryos, and brain and gonads of adult specimens, and sequenced using Illumina platform. Out of 194 miRNAs identified based on zebrafish database, 120 showed differential expression between male and female of O. niloticus. Additionally, 74 new miRNAs not detected in zefrafish database were found. Twenty-two miRNAs were tested by qPCR and five had their target candidate genes tested by luciferase reporter gene assay. The qPCR results showed that miR-10 family expression was high during the periods of 3 and 5dpf. Prediction software suggested that this family of miRNAs regulate the Hox genes family members. Therefore, were tested by qPCR and luciferase gene reporter assay, three Hox genes: Hoxa3a, HoxB3a and HoxD10a. The results showed that miR-10b have Hoxb3a and HoxD10a as target. In sex differentiation, the results of qPCR showed a high expression of miR-145-5p during the development of female embryos, while its possible target, Sox9, decreased. Moreover, the miR-181a expression decreased and his target gene, Cyp191a increased. The luciferase gene reporter assay validated the Cyp19a1 as a direct target of miR-181a, and Sox9 as a target of miR-145-5p. Our data suggest that, as in other vertebrates, Hox genes are extremely important in the development of Nile tilapia and are regulated by miR-10 ...