77 resultados para gender and sex - theories
Resumo:
Participation research has documented the effect of partner and parenthood status, thereby ignoring the dynamic aspect of status changes. Based on theoretical insights on changes in political resources and interest, this study looks at partnership and parenthood as dynamic characteristics. Using data from the Swiss Household Panel (SHP), it examines to what extent important life-cycle transitions in partnership and parental status influence various forms of political and civic participation and whether they affect men and women's participation differently. Our regression analyses reveal that particularly the entry into separation or divorce is a main key point driving change in political and civic participation. Its effect is also highly gendered. Following separation, women participate less in voting, whereas men's participation rates are not affected in a negative way. Separation even increases men's level of anticipated activism. Children entering or leaving the household do not seem to represent key points of change in political and civic participation of the couple. Yet, the transition to having school-aged children significantly increases some types of participation, at least for women.
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OBJECTIVE: The sensitivity and tolerance regarding ADHD symptoms obviously differ from one culture to another and according to the informants (parents, teachers, or children). This stimulates the comparison of data across informants and countries. METHOD: Parents and teachers of more than 1,000 school-aged Swiss children (5 to 17 years old) fill in Conners's questionnaires on ADHD. Children who are older than 10 years old also fill in a self-report questionnaire. Results are compared to data from a North American sample. RESULTS: Swiss parents and teachers tend to report more ADHD symptoms than American parents and teachers as far as the oldest groups of children are concerned. Interactions are evidenced between school achievement, child gender, and informants. A relatively low rate of agreement between informants is found. CONCLUSION: These results strengthen the importance to take into account all informants in the pediatric and the child psychiatry clinic, as well as in the epidemiological studies.
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In hybrid zones, endogenous counter-selection of hybrids is usually first expressed as reduced fertility or viability in hybrids of the heterogametic sex, a mechanism known as Haldane's rule. This phenomenon often leads to a differential of gene flow between sex-linked markers. Here, we address the possibility of a differential gene flow for Y chromosome, mtDNA and autosomal markers across the hybrid zone between the genetically and chromosomally well-differentiated species Sorex antinorii and Sorex araneus race Vaud. Intermarker comparison clearly revealed coincidental centre and very abrupt clines for all three types of markers. The overall level of genetic differentiation between the two species must be strong enough to hinder asymmetric introgression. Cyto-nuclear mismatches were also observed in the centre of hybrid zone. The significantly lower number of mismatches observed in males than in females possibly results from Y chromosome-mtDNA interactions. Results are compared with those previously reported in another hybrid zone between S. antinori and S. araneus race Cordon.
Resumo:
Bowlby proposed that the individual's social experiences, as early as in infancy, contribute to the construction of Internal Working Models (IWMs) of attachment, which will later guide the individual's expectations and behaviors in close relationships all along his or her life. The qualitative, individual characteristics of these models reflect the specificity of the individual's early experiences with attachment figures. The attachment literature globally shows that the qualities of IWMs are neither gender specific nor cultural specific. Procedures to evaluate IWMs in adulthood have been well established, based on narrative accounts of childhood experiences. Narrative procedures at earlier ages (e.g., in the preschool years) have been proposed, such as Bretherton's Attachment Story Completion Task (ASCT), to evaluate attachment representations. More than 500 ASCT narratives of preschoolers, coming from five different countries, have been collected, in the perspective of examining possible interactions between gender and culture regarding attachment representations. A specific Q-Sort coding procedure (CCH) has been used to evaluate several dimensions of the narratives. Girls' narratives appeared as systematically more secure than those of same-age boys, whatever their culture. The magnitude of gender differences, however, varied between countries. Taylor's model of gender-specific responses to stress and Harwood's and Posada's hypothesis on inter-cultural differences regarding caregiving are evoked to understand the differences across gender and countries.
Resumo:
BACKGROUND: Urinary creatinine excretion is used as a marker of completeness of timed urine collections, which are a keystone of several metabolic evaluations in clinical investigations and epidemiological surveys. METHODS: We used data from two independent Swiss cross-sectional population-based studies with standardised 24-hour urinary collection and measured anthropometric variables. Only data from adults of European descent, with estimated glomerular filtration rate (eGFR) ≥60 ml/min/1.73 m2 and reported completeness of the urinary collection were retained. A linear regression model was developed to predict centiles of the 24-hour urinary creatinine excretion in 1,137 participants from the Swiss Survey on Salt and validated in 994 participants from the Swiss Kidney Project on Genes in Hypertension. RESULTS: The mean urinary creatinine excretion was 193 ± 41 μmol/kg/24 hours in men and 151 ± 38 μmol/kg/24 hours in women in the Swiss Survey on Salt. The values were inversely correlated with age and body mass index (BMI). CONCLUSIONS: We propose a validated prediction equation for 24-hour urinary creatinine excretion in the general European population, based on readily available variables such as age, sex and BMI, and a few derived normograms to ease its clinical application. This should help healthcare providers to interpret the completeness of a 24-hour urine collection in daily clinical practice and in epidemiological population studies.
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The objective of this study was to assess breeding and dispersal patterns of both males and females in a monogyne (a single queen per colony) population of ants. Monogyny is commonly associated with extensive nuptial flights, presumably leading to considerable gene flow over large areas. Opposite to these expectations we found evidence of both inbreeding and sex-biased gene flow in a monogyne population of Formica exsecta. We found a significant degree of population subdivision at a local scale (within islands) for queens (females heading established colonies) and workers, but not for colony fathers (the males mated to the colony queens). However, we found little evidence of population subdivision at a larger scale (among islands). More conclusive support for sex-biased gene flow comes from the analysis of isolation by distance on the largest island, and from assignment tests revealing differences in female and male philopatry. The genetic similarity between pairs of queens decreased significantly when geographical distance increased, demonstrating limited dispersal and isolation by distance in queens. By contrast, we found no such pattern for colony fathers. Furthermore, a significantly greater fraction of colony queens were assigned as having originated from the population of residence, as compared to colony fathers. Inbreeding coefficients were significantly positive for workers, but not for mother queens. The queen-male relatedness coefficient of 0.23 (regression relatedness) indicates that mating occurs between fairly close relatives. These results suggest that some monogyne species of ants have complex dispersal and mating systems that can result in genetic isolation by distance over small geographical scales. More generally, this study also highlights the importance of identifying the relevant scale in analyses of population structure and dispersal.
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Abstract The great diversity of sex determination mechanisms in animals and plants ranges from genetic sex determination (GSD, e.g. mammals, birds, and most dioecious plants) to environmental sex determination (ESD, e.g. many reptiles) and includes a mixture of both, for example when an individual's genetically determined sex is environmentally reversed during ontogeny (ESR, environmental sex reversal, e.g. many fish and amphibia). ESD and ESR can lead to widely varying and unstable population sex ratios. Populations exposed to conditions such as endocrine-active substances or temperature shifts may decline over time due to skewed sex ratios, a scenario that may become increasingly relevant with greater anthropogenic interference on watercourses. Continuous exposure of populations to factors causing ESR could lead to the extinction of genetic sex factors and may render a population dependent on the environmental factors that induce the sex change. However, ESR also presents opportunities for population management, especially if the Y or W chromosome is not, or not severely, degenerated. This seems to be the case in many amphibians and fish. Population growth or decline in such species can potentially be controlled through the introduction of so-called Trojan sex genes carriers, individuals that possess sex chromosomes or genes opposite from what their phenotype predicts. Here, we review the conditions for ESR, its prevalence in natural populations, the resulting physiological and reproductive consequences, and how these may become instrumental for population management.
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In addition to differences in protein-coding gene sequences, changes in expression resulting from mutations in regulatory sequences have long been hypothesized to be responsible for phenotypic differences between species. However, unlike comparison of genome sequences, few studies, generally restricted to pairwise comparisons of closely related mammalian species, have assessed between-species differences at the transcriptome level. They reported that gene expression evolves at different rates in various organs and in a pattern that is overall consistent with neutral models of evolution. In the first part of my thesis, I investigated the evolution of gene expression in therian mammals (i.e.7 placental and marsupials), based on microarray data from human, mouse and the gray short-tailed opossum (Monodelphis domestica). In addition to autosomal genes, a special focus was given to the evolution of X-linked genes. The therian X chromosome was recently shown to be younger than previously thought and to harbor a specific gene content (e.g., genes involved in brain or reproductive functions) that is thought to have been shaped by specific sex-related evolutionary forces. Sex chromosomes derive from ordinary autosomes and their differentiation led to the degeneration of the Y chromosome (in mammals) or W chromosome (in birds). Consequently, X- or Z-linked genes differ in gene dose between males and females such that the heterogametic sex has half the X/Z gene dose compared to the ancestral state. To cope with this dosage imbalance, mammals have been reported to have evolved mechanisms of dosage compensation.¦In the first project, I could first show that transcriptomes evolve at different rates in different organs. Out of the five tissues I investigated, the testis is the most rapidly evolving organ at the gene expression level while the brain has the most conserved transcriptome. Second, my analyses revealed that mammalian gene expression evolution is compatible with a neutral model, where the rates of change in gene expression levels is linked to the efficiency of purifying selection in a given lineage, which, in turn, is determined by the long-term effective population size in that lineage. Thus, the rate of DNA sequence evolution, which could be expected to determine the rate of regulatory sequence change, does not seem to be a major determinant of the rate of gene expression evolution. Thus, most gene expression changes seem to be (slightly) deleterious. Finally, X-linked genes seem to have experienced elevated rates of gene expression change during the early stage of X evolution. To further investigate the evolution of mammalian gene expression, we generated an extensive RNA-Seq gene expression dataset for nine mammalian species and a bird. The analyses of this dataset confirmed the patterns previously observed with microarrays and helped to significantly deepen our view on gene expression evolution.¦In a specific project based on these data, I sought to assess in detail patterns of evolution of dosage compensation in amniotes. My analyses revealed the absence of male to female dosage compensation in monotremes and its presence in marsupials and, in addition, confirmed patterns previously described for placental mammals and birds. I then assessed the global level of expression of X/Z chromosomes and contrasted this with its ancestral gene expression levels estimated from orthologous autosomal genes in species with non-homologous sex chromosomes. This analysis revealed a lack of up-regulation for placental mammals, the level of expression of X-linked genes being proportional to gene dose. Interestingly, the ancestral gene expression level was at least partially restored in marsupials as well as in the heterogametic sex of monotremes and birds. Finally, I investigated alternative mechanisms of dosage compensation and found that gene duplication did not seem to be a widespread mechanism to restore the ancestral gene dose. However, I could show that placental mammals have preferentially down-regulated autosomal genes interacting with X-linked genes which underwent gene expression decrease, and thus identified a novel alternative mechanism of dosage compensation.
NPAS2 as a transcriptional regulator of non-rapid eye movement sleep: genotype and sex interactions.
Resumo:
Because the transcription factor neuronal Per-Arnt-Sim-type signal-sensor protein-domain protein 2 (NPAS2) acts both as a sensor and an effector of intracellular energy balance, and because sleep is thought to correct an energy imbalance incurred during waking, we examined NPAS2's role in sleep homeostasis using npas2 knockout (npas2-/-) mice. We found that, under conditions of increased sleep need, i.e., at the end of the active period or after sleep deprivation (SD), NPAS2 allows for sleep to occur at times when mice are normally awake. Lack of npas2 affected electroencephalogram activity of thalamocortical origin; during non-rapid eye movement sleep (NREMS), activity in the spindle range (10-15 Hz) was reduced, and within the delta range (1-4 Hz), activity shifted toward faster frequencies. In addition, the increase in the cortical expression of the NPAS2 target gene period2 (per2) after SD was attenuated in npas2-/- mice. This implies that NPAS2 importantly contributes to the previously documented wake-dependent increase in cortical per2 expression. The data also revealed numerous sex differences in sleep; in females, sleep need accumulated at a slower rate, and REMS loss was not recovered after SD. In contrast, the rebound in NREMS time after SD was compromised only in npas2-/- males. We conclude that NPAS2 plays a role in sleep homeostasis, most likely at the level of the thalamus and cortex, where NPAS2 is abundantly expressed.
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Studies of behaviour are increasingly focusing on acquisition of traits through cultural inheritance. Comparison of patterns of spatial population structure (FST) between neutral genetic loci and behavioural or cultural traits can been used to test hypotheses about demography, life history, and the mechanisms of inheritance/transmission of these traits in humans, chimpanzees and other animals. Here, we develop analytical expectations to show how FST in cultural traits can differ strongly from that measured at neutral genetic markers if migration is largely restricted to one sex but social learning is predominantly modelled on the other (e.g. males migrate, females serve as models for cultural traits), if one individual is the learning model for many, or if rates of innovation (individual learning) are high or rates of social learning are low. We discuss how comparisons of FST between genetic loci and behavioural traits can be applied to evaluate the importance of innovation in shaping patterns of cultural differentiation, as even low rates of innovation can considerably reduce FST, relative to observed structure at neutral genetic loci. Our results also suggest that differentiation in neutral cultural traits should occur over much smaller scales in species with male migration and female enculturation (or the reverse).
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Taking as its point of departure recent insights about the performative¦nature of genre, The Poetics and Politics of the American Gothic¦challenges the critical tendency to accept at face value that gothic¦literature is mainly about fear. Instead, Agnieszka Soltysik Monnet¦argues that the American Gothic, and gothic literature in general,¦is also about judgment: how to judge and what happens when¦judgment is confronted with situations that defy its limits.¦Poe, Hawthorne, Melville, Gilman, and James all shared a concern¦with the political and ideological debates of their time, but tended¦to approach these debates indirectly. Thus, Monnet suggests, while¦slavery and race are not the explicit subject matter of antebellum¦works by Poe and Hawthorne, they nevertheless permeate it through¦suggestive analogies and tacit references. Similarly, Melville, Gilman,¦and James use the gothic to explore the categories of gender and¦sexuality that were being renegotiated during the latter half of the¦century. Focusing on The Fall of the House of Usher, The Marble¦Faun, Pierre, The Turn of the Screw, and The Yellow Wallpaper,¦Monnet brings to bear minor texts by the same authors that further¦enrich her innovative readings of these canonical works. At the same¦time, her study persuasively argues that the Gothic's endurance¦and ubiquity are in large part related to its being uniquely adapted¦to rehearse questions about judgment and justice that continue to¦fascinate and disturb.