975 resultados para Fertility differentials
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Workers in less-secure jobs are often paid less than identical-looking workers in more secure jobs. We show that this lack of compensating differentials for unemployment risk can arise in equilibrium when all workers are identical and firms differ only in job security (i.e. the probability that the worker is not sent into unemployment). In a setting where workers search for new positions both on and off the job, the worker’s marginal willingness to pay for job security is endogenous, increasing with the rent received by a worker in his job, and depending on the behavior of all firms in the labor market. We solve for the labor market equilibrium and find that wages increase with job security for at least all firms in the risky tail of the distribution of firm-level unemployment risk. Unemployment becomes persistent for low-wage and unemployed workers, a seeming pattern of ‘unemployment scarring’ created entirely by firm heterogeneity. Higher in the wage distribution, workers can take wage cuts to move to more stable employment.
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We have established an in vitro culture system for adult schistosomes that allows monitoring gene expression for up to more than ten days. Comparing female worms that are paired with those that have been separated, we find distinct differences, clearly documenting an influence of the male in female gene expression. In perfect coincidence with classical observations that were based on histological techniques, we find that the male particularly regulates gene expression in those tissues that are characterized by cell proliferation, e.g. the vitellaria. From these results, we hypothesize that the key target for the inductive signal that is transferred from the male to the female during pairing is the activation of a growth factor that stimulates mitotic proliferation.
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Aim: This study examines the transition from fertility to obstetrical care of women who conceived through IVF. Materials & methods: 33 women filled out questionnaires before IVF, during pregnancy and after birth on infertility stress, maternal adjustment and depressive symptoms. During pregnancy, they participated in an interview about their emotional experiences regarding the transition. Responses were sorted into three categories: Autonomy, Dependence and Avoidance. Results: Exploratory results show that 51.5% of women had no difficulties making the transition (Autonomy), 21.2% had become dependent (Dependence) and 27.3% had distanced themselves from the specialists (Avoidance). Women who became dependent had more trouble adjusting to motherhood and more depressive symptoms. Conclusion: Difficulty making the transition may be linked to decreased ability to adjust to motherhood and more postpartum depressive symptoms.
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We define a new version of the exterior derivative on the basic forms of a Riemannian foliation to obtain a new form of basic cohomology that satisfies Poincaré duality in the transversally orientable case. We use this twisted basic cohomology to show relationships between curvature, tautness, and vanishing of the basic Euler characteristic and basic signature.
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The existing literature shows that social interactions in individuals' networks affect their reproductive attitudes and behaviors through three mechanisms: social influence, social learning, and social support. In this paper, we discuss to what extent the Theory of Planned Behavior (TPB), an individual based theorization of intentions and behavior used to model fertility, takes these social mechanisms into account. We argue that the TPB already integrates social influence and that it could easily accommodate the two other social network mechanisms. By doing so, the theory would be enriched in two respects. First, it will explain more completely how macro level changes eventually ends in micro level changes in behavioral intentions. Indeed, mechanisms of social influence may explain why changes in representations of parenthood and ideal family size can be slower than changes in socio-economic conditions and institutions. Social learning mechanisms should also be considered, since they are crucial to distinguish who adopts new behavioral beliefs and practices, when change at the macro level finally sinks in. Secondly, relationships are a capital of services that can complement institutional offering (informal child care) as well as a capital of knowledge which help individuals navigate in a complex institutional reality, providing a crucial element to explain heterogeneity in the successful realization of fertility intentions across individuals. We develop specific hypotheses concerning the effect of social interactions on fertility intentions and their realization to conclude with a critical review of the existing surveys suitable to test them and their limits.
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Future of Fertility Services in Northern Ireland (From People to Parents)
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Eye colour of Triatoma infestans is controlled at a single autosomal locus, with black-eye as the dominant gene and red-eye as the recessive. Inheritance of these characters follows a classical Mendelian system, enabling eye colour to be used as a marker for studies of mating frequency. We found no significant differences in oviposition rates and egg hatching rates irrespective of parental phenotypes. Different mating schedules between red-eye and black-eye parents showed that eye colour did not affect mating competence. Females mated with a single male or with different males together or in succession produced similar numbers of fertile eggs, with the eye colour of the offspring reflecting exposure to the different males. We conclude that although a single mating can provide sufficient sperm for the whole reproductive life of the female, multiple matings can result in balanced assortative sperm usage from the spermatheca.
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There are many negative impacts of obesity on fertility. Obese couples present decreased sperm count, decreased ovulation and conception rates, increased erectile dysfunction and spontaneous abortion rate as well as increased maternal and foetal complications of pregnancy. Moreover, obesity tends to decrease response to fertility treatments. Fortunately, intensive lifestyle modifications can restore fertility while decreasing pregnancy complications risk. With the increasing trend of obesity to affect young populations, taking care of these infertile couples rapidly is capital to restore fertility and decrease its related pregnancy complications.
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This article uses a mixed methods design to investigate the effects of social influence on family formation in a sample of eastern and western German young adults at an early stage of their family formation. Theoretical propositions on the importance of informal interaction for fertility and family behavior are still rarely supported by systematic empirical evidence. Major problems are the correct identification of salient relationships and the comparability of social networks across population subgroups. This article addresses the two issues through a combination of qualitative and quantitative data collection and analysis. In-depth interviewing, network charts, and network grids are used to map individual personal relationships and their influence on family formation decisions. In addition, an analysis of friendship dyads is provided.
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Improvement in cancer treatments resulted in an increased number of men surviving cancer. Quality of life has become an important issue in these patients. Anti cancer treatments might have transient or definitive harmful effects on male fertility. Sperm cryoconservation is currently the only proven method to preserve fertility in patients undergoing oncologic treatment. It should be proposed to every patient at reproductive age before chemotherapy, radiotherapy or any surgery involving reproductive tract. Despite low use rate, this simple method could allow patients presenting infertility after treatment to father a child.
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In seven studied communities of Western Mexico, triatomine specimens were sympatrically collected, some with atypical morphological characteristics in contrast to pure specimens, which were presumed to be hybrids. More than 200 specimens of Meccus pallidipennis and Meccus longipennis with brown-yellow markings on dorsal connexival segments were collected in Ahuacapán and Quitupan. In La Mesa, more than 60 specimens similar to Meccus picturatus in most morphological characteristics (including size) were collected, although they presented a largely yellowish corium like M. pallidipennis. Interfertility was proven between all of the studied wild hybrid specimens, as well as between all the experimental laboratory hybrids. Two different phenotypes (M. picturatus and M. longipennis) were obtained from crosses between M. picturatus x M. picturatus and M. longipennis x M. longipennis from the three studied localities in state of Nayarit as from La Mesita. Results support the hypothesis that the subspecific ranking of those triatomines may, therefore, be more appropriate because reproductive isolation has not been developed and complete interbreeding was recorded.
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CONTEXT AND OBJECTIVE: The optimal strategy for inducing fertility in men with congenital hypogonadotropic hypogonadism (CHH) is equivocal. Albeit a biologically plausible approach, pretreatment with recombinant FSH (rFSH) before GnRH/human chorionic gonadotropin administration has not been sufficiently assessed. The objective of the study was to test this method. DESIGN AND SETTING: This was a randomized, open-label treatment protocol at an academic medical center. PATIENTS AND INTERVENTIONS: GnRH-deficient men (CHH) with prepubertal testes (<4 mL), no cryptorchidism, and no prior gonadotropin therapy were randomly assigned to either 24 months of pulsatile GnRH therapy alone (inducing endogenous LH and FSH release) or 4 months of rFSH pretreatment followed by 24 months of GnRH therapy. Patients underwent serial testicular biopsies, ultrasound assessments of testicular volume, serum hormone measurements, and seminal fluid analyses. RESULTS: rFSH treatment increased inhibin B levels into the normal range (from 29 ± 9 to 107 ± 41 pg/mL, P < .05) and doubled testicular volume (from 1.1 ± 0.2 to 2.2 ± 0.3 mL, P < .005). Histological analysis showed proliferation of both Sertoli cells (SCs) and spermatogonia, a decreased SC to germ cell ratio (from 0.74 to 0.35), and SC cytoskeletal rearrangements. With pulsatile GnRH, the groups had similar hormonal responses and exhibited significant testicular growth. All men receiving rFSH pretreatment developed sperm in their ejaculate (7 of 7 vs 4 of 6 in the GnRH-only group) and showed trends toward higher maximal sperm counts. CONCLUSIONS: rFSH pretreatment followed by GnRH is successful in inducing testicular growth and fertility in men with CHH with prepubertal testes. rFSH not only appears to maximize the SC population but also induces morphologic changes, suggesting broader developmental roles.
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The glucocorticoid-induced leucine zipper (Tsc22d3-2) is a widely expressed dexamethasone-induced transcript that has been proposed to be important in immunity, adipogenesis, and renal sodium handling based on in vitro studies. To address its function in vivo, we have used Cre/loxP technology to generate mice deficient for Tsc22d3-2. Male knockout mice were viable but surprisingly did not show any major deficiencies in immunological processes or inflammatory responses. Tsc22d3-2 knockout mice adapted to a sodium-deprived diet and to water deprivation conditions but developed a subtle deficiency in renal sodium and water handling. Moreover, the affected animals developed a mild metabolic phenotype evident by a reduction in weight from 6 months of age, mild hyperinsulinemia, and resistance to a high-fat diet. Tsc22d3-2-deficient males were infertile and exhibited severe testis dysplasia from postnatal d 10 onward with increases in apoptotic cells within seminiferous tubules, an increased number of Leydig cells, and significantly elevated FSH and testosterone levels. Thus, our analysis of the Tsc22d3-2-deficient mice demonstrated a previously uncharacterized function of glucocorticoid-induced leucine zipper protein in testis development.