Dissertations / Theses on the topic 'Transfert de fertilité'
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Drouineaud, Véronique. "Rôle de la protéine de transfert des phospholipides (PLTP) dans le système reproductif mâle." Dijon, 2007. http://www.theses.fr/2007DIJOMU10.
Full textPhospholipid transfer protein (PLTP) was first described as a plasma factor that facilitates the exchange of phospholipid species between circulating proteins. In addition, PLTP can bind and transfer several other amphipathic compounds, including unesterified cholesterol, lipopolysaccharides, diacylglycerides and vitamin E. Vitamin E is well-known for its anti-oxidative properties and is a major determinant of male fertility. The aim of the present study was to search for the presence of PLTP and to identify the physiological role of this protein in reproductive biology. First, PLTP was detected in human seminal plasma and accounted for almost 80% of the phospholipid transfer activity present in seminal plasma. Secondly, the effect of PLTP on reproductive biology was investigated through the comparison of wild-type and PLTP-knocked out mice. We show that PLTP deficiency is associated with hypofertility of mouse males but not mouse females. PLTP deficiency tended to reduce sperm motility and accounts for a significant decrease in total number of pups produced over a 2-month breeding period of PLTP knocked out mice (-32%, P<0. 03). In vitroo fertilization rates of wild-type oocytes with spermatozoa from PLTP-deficient males were markedly reduced as compared with those measured with spermatozoa from wild-type males (-60%, P<0. 05). PLTP is highly expressed in epididymis of mouse males, and alpha-tocopherol was significantly less abundant in cauda and caput epididymis of PLTP-deficient mice as compared with wild-type counterparts. These observations suggest that PLTP is a new key factor in male fertility, probably via the transfer of vitamin E
Rokia, Sarah. "Contribution à la modélisation des processus d'agrégation et de transfert d'éléments nutritifs dans les Technosols construits à partir de déchets." Thesis, Université de Lorraine, 2014. http://www.theses.fr/2014LORR0009/document.
Full textGreening of urban spaces requires large amounts of arable soil which is a non-renewable resource. To preserve this resource, a strategy is proposed to build fertile Technosols from wastes and by-products by pedological engineering. The properties of Technosols are highly influenced by their constitutive technogenic materials. In order To create favourable mixtures of materials for urban plant growth a preliminary scientific analysis is required. The fertility of the mixtures and their evolution can be assessed by the study of the aggregation process and nutrients transfer during the first stage of pedogenesis. An experimental model of constructed Technosol is proposed in this work. From this model a methodology is developed for the selection of eleven constitutive materials (e.g. bricks, compost made of sludge and green waste, concrete, demolition rubble, excavated earth materials, green wastes, paper mill sludge, sewage sludge, street sweeping wastes, track ballast). Each of these materials is representative of wastes deposits listed European wide and they are suitable candidates for the construction of fertile soils. The fertility of each pure material and of selected mixtures has been determined. Thereafter, experiments under controlled conditions enabled to assess the impact of different pedogenesis factors (e.g. anthropogenic, climatic and biological) involved in the definition of the fertility of constructed Technosols. The results demonstrate (i) the feasibility of the formulation of fertile constructed Technosols exclusively with two or three wastes presenting contrasted physico-chemical properties; and (ii) that the properties of selected mixtures can be modelled using the initial properties of their constitutive parent materials ; (iii) that during the first stage of pedogenesis of the mixtures, depending on parent materials nature and properties, stable aggregates can be formed, (iv) that nutrients transfer are highly dependent on organic matter nature and the process of particles mixing. The delivery of nutrients (e.g. phosphorus) seems to be related to the amounts and size of the formed aggregates and, consequently, to the established porosity. The understanding of the functioning and evolution of Technosols constructed with waste materials provides new knowledge for the development of pedological engineering. The methodology of wastes selection and the mixing process developed in this work enables us to propose mixtures and constructed soils favourable to various uses. The evolution models of the mixtures developed in this work allow the prediction of the physico-chemical fertility of constructed Technosols. The results acquired during this thesis are the main basis of a decision support tool for green spaces operators developed in the framework of the research program SITERRE-ADEME (2010-2015). The use of this decision support tool for plant biomass production, has to be associated with an expertise in soil construction
Demay, Joséphine. "La disponibilité en phosphore des sols pourrait-elle limiter la production de l’agriculture biologique dans un contexte de forte expansion ?" Electronic Thesis or Diss., Bordeaux, 2024. http://www.theses.fr/2024BORD0059.
Full textFaced with the current environmental and climate crises, food production systems urgently need to transform. Among possible alternatives, organic agriculture is often put forward. Yet, it is still under debate whether large scale expansion of organic farming would be limited by nutrient availability. So far, studies have shown that provided a strong redesign of food systems including a reduction in livestock densities and food waste, changes in diets and re-location of crops and livestock, the global food demand could be met by converting up to 60% of cropland areas to organic agriculture. Above this threshold, nitrogen (N) limitations would lead to an unsatisfied demand. However, these studies have not considered whether soil available phosphorus (P) could limit organic food production in the long run. This question arises because mineral P fertilizers, which currently contribute to more than half of global soil P inputs to cropland soils, are banned under organic farming. Filling this knowledge gap is of utmost importance not only to assess the ability of organic farming to expand globally but also in the context of the slow and inevitable depletion of phosphate rock reserves. In this thesis, we first quantified the reliance of current agricultural soil P fertility on past and current use of mineral P fertilisers. We then analysed the extent to which organic food production would be affected by the potential soil P deficits in a hypothetical 100% organic world. Finally, we quantified the N and P fertility transfers between grassland and cropland soils in order to assess their contribution to the total nutrient inputs to cropland soils. To simulate a 100% organic world, we coupled two already published models: the GOANIM model and the GPASOIL model and ran them for 100 years at a spatially explicit resolution. Overall, we show that the current P fertility of agricultural soils is highly reliant on the cumulated use of mineral P fertilizers over the 1950-2017 period, half of the global soil agricultural available P being of anthropic origin. This global pattern hides great discrepancies between countries, reflecting contrasting historical uses of mineral P fertilizers and contrasting soil biogeochemical backgrounds. The strong reliance on mineral P inputs is both an opportunity and an obstacle to the development of organic farming. On the one hand, heavy dependence on mineral P fertilizers often results in large inherited soil P stocks, making it easier to switch to organic farming. However, this reliance questions the long-term sustainability of farming systems without any mineral P inputs. Our simulations of a 100% organic world revealed that while crop production would be strongly limited by N in the short term, long term P limitations would also strongly affect food production, especially in places with initial low level of P fertility, high levels of production and a high share of N-fixing crop in rotations. After 100 years of farming the world organically, global food production would be reduced by 41%, with global cropland and grassland soil P deficit contributing to 39% and 18% of that loss respectively. We also show that under organic farming, fertility transfers from grassland to cropland soils contribute to 13% and 37% of total N and P inputs to cropland soils respectively, making cropland production levels reliant on the fertility of grassland systems. Overall, our work provides novel knowledge on the potential limitations of organic production by agricultural soil available P, highlighting long term risks for food security in a 100% organic world. Finally, we discuss various options for limiting this global soil P deficit, which include better connected livestock and crop production systems to enhance fertility transfers, closing the P cycle by limiting soil erosion and by better recycling of household organic waste and human excreta back to agricultural soils
Suharsono. "Effet du gène mitochondrial atp9 non-édité sur la fertilité, chez des plantes transgéniques de nicotiana tabacum." Bordeaux 2, 1993. http://www.theses.fr/1993BOR28256.
Full textHernould, Michel. "Etude de l'expression chez des plantes transgéniques, d'un gène mitochondrial non-édité (atp9) : effet sur la fertilité." Bordeaux 2, 1993. http://www.theses.fr/1993BOR28229.
Full textBisson, Anne. "Influence de l'organisation spatiale et de la pression d'herbivorie sur les transferts de fertilité et la productivité des systèmes agro-sylvo-pastoraux : approche écologique de questions agronomiques par l'utilisation de modèles mathématiques." Thesis, Montpellier, SupAgro, 2018. http://www.theses.fr/2018NSAM0052.
Full textThe sustainability of agro-ecosystem functioning and the management of the associated ecosystem services is one of the major challenges of agronomic and environmental sciences. West African agro-sylvo-pastoral systems (WA-ASPS), which have been studied by the scientific community for a long time, offer an interesting case study. Traditionally, the fertility of these agro-ecosystems relies on a very high rate of nutrient recycling within the agro-ecosystem maintained by both fallowing and livestock induced nutrient transfers.Socio-economic and demographic pressures lead to major changes in the spatial and temporal organization of WA-ASPS and in the associated agricultural practices, including those related to livestock. In this thesis, we are interested in the impact of these changes on crop and meat production at the scale of the agro-ecosystem.We chose to study ASPS by developing and analyzing mathematical models using the ecological concept of meta-ecosystems. In each of the three models proposed, we tried to represent the ASPS as simply as possible, by including the key biogeochemical mechanisms (plant growth, mineralization, leaching, deposition...) and the agricultural practices of interest. The aim was both to understand how mechanisms interact according to the practices and to identify emerging properties at the scale of the agro-ecosystem.Each model was developed to study the effect of a limited number of agricultural practices on the organization of spatial components or on the connectivity between spatial components.In the first part of this work, we studied the influence of the structure of the WA-ASPS on the agricultural production of these systems. In the model, four interconnected subsystems are represented: the compound ring, the bush ring, the savanna and the dwellings. The year is decomposed in two seasons: the dry and the rainy seasons, the dynamic of the system being different for each season. With this model, we studied the influence of three driving-forces on the crop production: (1) the rotation duration and duration of fallows within rotations, (2) the proportion of the agro-ecosystem surface allocated to the different cropland areas (compound/bush) and (3) the presence/absence of livestock in the agro-ecosystem. The results of this work highlight the ecosystem services provided by the savanna, the role of livestock as a "nutrient pump" from rangeland to cropland and the interactions between livestock effects and fallow effects on nutrient fluxes. In the second part, we used tools provided by control theory to take into account the variability over time of agricultural practices. We showed that by varying the herbivory pressure over time in an appropriate way, an additional gain in production is possible (compared to the one obtained with a constant herbivory pressure) for the same amount of nutrients transferred from rangelands to croplands.In the last part of this work, the multi-criteria optimization of the functioning of the agro-ecosystem makes it possible to address the complexity of the objectives of WA-ASPS as a production system and to take into account risks management in these systems. Our results highlight that trade-offs between crop and animal production may be linked to the choice of crops. Our results also show that external sources of nutrients can lead to an increase in productions, but that their efficiency decreases as their quantity increases. At the interface between ecology and agronomy, and by using tools from other fields, this modeling work offers new perspectives for optimizing crop production and fertility management in ASPS
McGowan, Rebecca. "Aneuploid Embryo Transfer: Clinical Policies and Provider Opinions at U.S. Fertility Clinics." University of Cincinnati / OhioLINK, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1563527467302174.
Full textUnderhill, Katharine Lynne. "Transfer and cytogenetic analysis of day 4 embryos in PMSGhCG treated prepuberal gilts." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66237.
Full textLi, Zhuoyang. "Fertility and pregnancy outcomes following fresh versus frozen-thawed embryo transfer in assisted reproductive technology." Thesis, The University of Sydney, 2019. http://hdl.handle.net/2123/20330.
Full textŽamac, Jovan. "Education, pensions, and demography /." Uppsala : Department of Economics, Uppsala University, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-7433.
Full textSuperti, Luiz Henrique Ferreira Cruz e. "Efeitos do programa brasileiro de transferência de renda sobre a fecundidade: evidências atravéss do uso de regressão descontínua." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/12/12138/tde-02102018-114154/.
Full textThe Brazilian cash transfer program Balsa Familia is a very, if not the most, important pil- lar of Brazil\'s welfare system. However, there is a common sense that the program\'s trans- fers incentive beneficiary couples to have more children. Using federal data (Cadunico and Caixa databases) and the eligibility rules for the program, I propose a quasi-experimental approach to verify both unconditional (UCT) and conditional transfers (CCT) on the beneficiaries\' fertility rates between 2011 and 2015, through a fuzzy regression disconti- nuity approach. Measure problems associated with the data (e.g.: manipulation, heaping, attriton), are solved using a non parametric estimation proposed by Gerard, Rokkanen & Rothe (2016), which determines lower and upper bounds for treatment effects. On one hand, there is no evidence that the CCT component affects the beneficiaries\' fertility rates, but on another, the more flexible component of Bolsa Familia, UCT, possibly reduced the fertility rates for the most poor. Those results are counter intuitive with the theoretical literature so far, but in line with the majority of other studies analyzing similar transfer programs in Latin America.
Wilsher, Sandra Ann. "Studies in equine reproduction." Thesis, University of Bedfordshire, 2009. http://hdl.handle.net/10547/134931.
Full textFiong, à Bitegni Jean-Bosco. "Entraide familiale et fécondité en contexte de pauvreté : le cas du Cameroun." Thesis, Paris 10, 2015. http://www.theses.fr/2015PA100046/document.
Full textThis thesis wondered mainly about the link between the family mutual aid and the fertility in context of poverty. Thus she accentuated the impact on the fertility of the changes of the behavior of the households towards the family mutual aid. We tried to identify the factors of the reduction in the fertility observed in Cameroon, and tu discuss the idea according to which a weakening of the system of the family mutual aid would be a determiner of fertility. Among others, we also looked to raise the transformations undergone by the Cameroonian households (configuration and composition), due the impact of the poverty on their organizations. By way of results, besides the beginning of a weakening of the system of family mutual aid, other factors such as the reduction in the infanto-young mortality, etc., explain the reduction of the fertylity in Cameroon. If we thus observe an obstinacy of the family mutual aid in Cameroon in spite of the poverty, let us note nevertheless an increase in importance of the nuclearization of family which is translated by a preference to help his remote relations through the financial support, instead of having them near one through the cohabitation
Sills, Eric Scott. "An evidence-based policy for the provision of subsidised fertility treatment in California : integration of array comparative genomic hybridisation with IVF and mandatory single embryo transfer to lower multiple gestation and preterm birth rates." Thesis, University of Westminster, 2013. https://westminsterresearch.westminster.ac.uk/item/8z17y/an-evidence-based-policy-for-the-provision-of-subsidised-fertility-treatment-in-california-integration-of-array-comparative-genomic-hybridisation-with-ivf-and-mandatory-single-embryo-transfer-to.
Full textMabeu, Marie Christelle. "Institutions and Immutable Causes of Human Capital." Thesis, Université d'Ottawa / University of Ottawa, 2020. http://hdl.handle.net/10393/40683.
Full textBerbel, Cláudio Sztulman. "Interações econômicas entre capital humano e fecundidade." reponame:Repositório Institucional do FGV, 2011. http://hdl.handle.net/10438/9947.
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In this article we show evidences that conditional cash transfer programs (CCTs) can be very effective to enhance changes in people reproductive behavior. Using the event of the launching of Bolsa Familia, we first test the hypothesis that teenage pregnancy would be stimulated by being perceived as a potential facilitator of program participation. Then, we use the heterogeneity in the concession of the benefit to adolescent mothers documented between brazilian states as an exogenous source of variation in the incentives faced by the young women in each place, since pregnancy would be perceived as a factor of non-participation in some places. The results of both estimations demonstrate a high level of response of the poorest people of the population to indirect and financially small incentives. Besides suggesting the alteration of Bolsa Familia participation rules, our analysis confirm the potential of CCT programs to achieve voluntarily fertility reduction and maybe even STD prevention, which are relevant to all regions denoted by poverty.
O primeiro artigo desta tese procura medir o impacto do programa Bolsa Familia sobre a gravidez juvenil, discutindo também a utilização de programas de transferência condicional de renda para a diminuição da fecundidade em áreas de pobreza. O segundo artigo realiza um exercício contrafactual para estimar o impacto de aumentos no investimento em educação sobre o consumo, considerando não só o aumento da produtividade, mas também o impacto da nova educação sobre a fecundidade das pessoas.
Thorne, Jacob Westley. "Fertility of Beef Recipients Following a Fixed-Time Embryo Transfer Protocol that Includes Follicle Stimulating Hormone Diluted in Hyaluronan." Thesis, 2013. http://hdl.handle.net/1969.1/149601.
Full text林語宸. "Will increasing government transfer payments improve the fertility level? An application of threshold regression model." Thesis, 2013. http://ndltd.ncl.edu.tw/handle/49219823388201629079.
Full textOh, Seung-Yun. "Social emulation, the evolution of gender norms, and intergenerational transfers: Three essays on the economics of social interactions." 2013. https://scholarworks.umass.edu/dissertations/AAI3589118.
Full textHurst, Michael James. "Intergeneric hybrids designed to transfer restoration of male fertility from radish (Raphanus sativus) to rape (Brassica napus) with the ogu male sterile cytoplasm and the effect of elevated temperatures on seed production from intergeneric crosses." 1985. http://hdl.handle.net/1993/28892.
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