969 resultados para Female Choice


Relevância:

20.00% 20.00%

Publicador:

Resumo:

The aim of the present study was to determine whether and how rats can use local olfactory cues for spatial orientation. Rats were trained in an eight-arm radial maze under different conditions as defined by the presence or absence of supplementary olfactory cues marking each arm, the availability of distant visuospatial information, and the illumination of the maze (light or darkness). The different visual conditions were designed to dissociate among the effects of light per se and those of visuospatial cues, on the use of olfactory cues for accurate arm choice. Different procedures with modifications of the arrangement of olfactory cues were used to determine if rats formed a representation of the spatial configuration of the olfactory cues and if they could rely on such a representation for accurate arm choice in the radial maze. The present study demonstrated that the use of olfactory cues to direct arm choice in the radial arm maze was critically dependent on the illumination conditions and implied two different modes of processing of olfactory information according to the presence or the absence of light. Olfactory cues were used in an explicit manner and enabled accurate arm choice only in the absence of light. Rats, however, had an implicit memory of the location of the olfactory cues and formed a representation of the spatial position of these cues, whatever the lighting conditions. They did not memorize the spatial configuration of the olfactory cues per se but needed these cues to be linked to the external spatial frame of reference.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The rise in world trade since 1970 has been accompanied by a rise in the geographic span of control of management and, hence, also a rise in the e ective international mobility of labor services. We study the e ect of such a globalization of the world's labor markets. The world's welfare gains depend positively on the skill-heterogeneity of the world's labor force. We nd that when peoplecan choose between wage work and managerial work, the worldwide labor market raises output by more in the rich and the poor countries, and by less in the middle-income countries. This is because the middle-income countries experience the smallest change in the factor-price ratio, and where the option to choose between wage work and managerial work has the least value in the integratedeconomy. Our theory also establishes that after economic integration, the high skill countries see a disproportionate increase in managerial occupations. Using aggregate data on GDP, openness and occupations from 115 countries, we find evidence for these patterns of occupational choice.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

OBJECTIVES: The aim of this study was to evaluate the risk factors associated with Contegra graft (Medtronic Minneapolis, MN, USA) infection after reconstruction of the right ventricular outflow tract. METHODS: One hundred and six Contegra grafts were implanted between April 1999 and April 2010 for the Ross procedure (n = 46), isolated pulmonary valve replacement (n = 32), tetralogy of Fallot (n = 24), double-outlet right ventricle (n = 7), troncus arteriosus (n = 4), switch operation (n = 1) and redo of pulmonary valve replacement (n = 2). The median age of the patients was 13 years (range 0-54 years). A follow-up was completed in all cases with a median duration of 7.6 years (range 1.7-12.7 years). RESULTS: There were 3 cases of in-hospital mortality. The survival rate during 7 years was 95.7%. Despite the lifelong endocarditis prophylaxis, Contegra graft infection was diagnosed in 12 (11.3%) patients at a median time of 4.4 years (ranging from 0.4 to 8.7 years). Univariate analysis of preoperative, perioperative and postoperative variables was performed and the following risk factors for time to infection were identified: female gender with a hazard ratio (HR) of 0.19 (P = 0.042), systemic-to-pulmonary shunt (HR 6.46, P < 0.01), hypothermia (HR 0.79, P = 0.014), postoperative renal insufficiency (HR 11.97, P = 0.015) and implantation of permanent pacemaker during hospitalization (HR 5.29, P = 0.075). In 2 cases, conservative therapy was successful and, in 10 patients, replacement of the infected valve was performed. The Contegra graft was replaced by a homograft in 2 cases and by a new Contegra graft in 8 cases. Cox's proportional hazard model indicated that time to graft infection was significantly associated with tetralogy of Fallot (HR 0.06, P = 0.01), systemic-to-pulmonary shunt (HR 64.71, P < 0.01) and hypothermia (HR 0.77, P < 0.01). CONCLUSION: Contegra graft infection affected 11.3% of cases in our cohort, and thus may be considered as a frequent entity that can be predicted by both intraoperative and early postoperative factors. After the diagnosis of infection associated with the Contegra graft was confirmed, surgical treatment was the therapy of choice.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Literature on sex occupational segregation has typically focused on the micro and macro determinants of it, on mobility patterns over the life course, on implications of segregation and mobility for gender inequalities. Rarely the link between sex-type occupations and women’s risk of labour market interruptions over family formation has been explored. In this piece of work we shall analyse whether women who are working in the female-dominated, male-dominated or integrated occupations have more or less chances to remain attached to the labour market, controlling for qualifications, class, sector and contract positions. By drawing from ECHP, and comparing Italy, Spain, Denmark and the UK, we shall in particular see whether such connection varies across countries with different institutional and cultural configurations.We find that, ceteris paribus, only in the UK the sex-composition of an occupation matters: women in female occupations are more likely to move to inactivity than women in mixed or male occupations. In the other countries considered the main cleavages lie elsewhere. In Italy what matters most is the sector of employment (public vs. private). In Spain the sector is relevant too, but also social class and the type of contract held (permanent vs. temporary). In Denmark women’s transitions to inactivity are largely independent of human capital and job characteristics.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper is aimed at exploring the determinants of female activity from a dynamic perspective. An event-history analysis of the transition form employment to housework has been made resorting to data from the European Household Panel Survey. Four countries representing different welfare regimes and, more specifically, different family policies, have been selected for the analysis: Britain, Denmark, Germany and Spain. The results confirm the importance of individual-level factors, which is consistent with an economic approach to female labour supply. Nonetheless, there are significant cross-national differences in how these factors act over the risk of abandoning the labour market. First, the number of trnasitions is much lower among Danish working women than among British, German or Spanish ones, revealing the relative importance of universal provision of childcare services, vis-à-vis other elements of the family policy, as time or money.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The following dissertation proposes a qualitative approach on the matter ofadvertising, society and construction of identity, based on the effect of householdappliances commercials in constructing female identity of Spanish women today.Conclusions will be drawn based on a juxtaposition of social background andadvertising content and on how Spanish women of today perceive the evolution offemale imagery depicted in advertisements. The aim is to demonstrate how muchcommercials mirrors society and how far it reinforces paradigms no longer existing

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This paper revisits the issue of the regulatory choice between a mandatory label and a minimum-quality standard. When the cost of regulation is relatively low, we show that the socially optimal choice depends on the producers’ cost structure for complying with regulation and improving quality. Under a marginal cost for improving quality, the mandatory labeling is sufficient for reaching the socially optimal level of quality. Under a fixed cost for improving quality, we show that each instrument or the combination of both instruments may emerge at the equilibrium.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The goal of this follow-up study was to assess the long-term survival of all patients having undergone a first PTCA between 1981 and 1990 and to relate the outcome to the baseline clinical and angiographic state. Although PTCA has become a widely accepted therapeutic choice for revascularization, the authors lacked information on long-term outcome. Data was collected by questionnaire, the end points being a second PTCA, MI, CABG, death or any of these events. The survival curves were constructed using the Kaplan-Meier method. Multivariate analysis was performed by a Cox proportional hazards model. Complete follow-up data were collected for 1,071 patients for a mean period of 7.4 years (SEM +/- 1.98 months) with a range of 0 to 14 years. Mean age was 57 years. PTCA was successful in 85% of patients. In-hospital event rates were death 1.3%, MI 4.4%, and emergency CABG 2.9%. Overall survival at 14 years was 69% (SEM +/- 9.6%) and event-free survival was 47% (SEM +/- 5.8%). MI rate was 11%, CABG 15%, and 20% of patients underwent repeat PTCA. Presence of cardiovascular risk factors, poor left ventricular ejection fraction, and prior CABG were significantly associated with poorer event-free survival. The short-term observations are consistent with results reported by the other follow-up studies. In addition, the study found a total survival rate 14 years after a first PTCA of 69% and 47% of the cohort remained event free.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

An experiment was conducted in France to evaluate the impact of health information on consumers’ choice between two different types of fish. Successive messages revealing risks (methylmercury) and benefits (omega-3s) of consuming the fish, along with consumption recommendations, were delivered. Results show a significant difference of reaction according to the order and type of information. The information about risks had a larger marginal impact on change in willingness to pay (WTP) than did the information about benefits. While the results show that detailed messages on risks/benefits, including recommendations for nutrition behavior, matter in the modification of WTP, 40% of respondents did not change their initial choices after the revelation of health information.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Several internally fertilizing hermaphroditic animals can only perform one sexual role at a time. In such species, two individuals that engage in a copulation may have different interests in acting as male or female. A gender choice must be made which, if both individuals have the same preference, may give rise to a severe sexual conflict. Here we tested the hypothesis that gender choice could be influenced by mating history, using the freshwater snail, Physa acuta. We recorded the copulatory behaviour of 240 pairs composed of a focal individual and a partner, each either short- or long-isolated. We found that the time to the first copulation was unaffected by isolation status, suggesting that first contacts in this species are random processes. In contrast, the duration of copulations and the frequency of rejection behaviours suggested that individual gender preference switches from male biased to female biased as isolation increases. In addition, snails rejected copulations more frequently when presented to a partner with the same isolation status. Reciprocity, measured as the rate of gender swapping between the first and second copulations, was high irrespective of gender status. We suggest possible evolutionary causes for this gender preference switch and discuss its potential importance in natural population as well as its consequences for the maintenance of hermaphroditism

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Melanin-based coloration exists in 2 types: black eumelanism and reddish-brown pheomelanism, which both have a strong heritable component. To test whether these 2 types of melanism are associated with alternative adaptations, we carried out a correlative study over 8 years and an experiment in a Swiss population of barn owls, Tyto alba. This species varies in coloration from reddish-brown to white and from lightly to heavily marked with black spots. Based on the fact that plumage coloration and spottiness are male- and female-specific secondary sexual characters, respectively, we examined whether the probability of breeding is associated with the degree of pheomelanism in males and of eumelanism in females. In males, recruited nestlings were significantly less reddish-brown than their nonrecruited nest mates. In females, individuals displaying larger black spots started to breed at a younger age and had a higher survival, and females with experimentally reduced plumage spottiness bred less often than control females. Therefore, in the barn owl, the degree of male pheomelanism is associated with the probability of being recruited in the local population, whereas the degree of female eumelanism correlates with age at sexual maturity, survival probability, and also the probability of skipping reproduction.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

In insects, the steroid hormone 20-hydroxyecdysone (20E) coordinates major developmental transitions. While the first and the final steps of 20E biosynthesis are characterized, the pathway from 7-dehydrocholesterol to 5β-ketodiol, commonly referred as the "black box", remains hypothetical and whether there are still unidentified enzymes is unknown. The black box would include some oxidative steps, which are believed to be mediated by P450 enzymes. To identify new enzyme(s) involved in steroid synthesis, we analyzed by small-scale microarray the expression of all the genes encoding P450 enzymes of the malaria mosquito Anopheles gambiae in active steroidogenic organs of adults, ovaries from blood-fed females and male reproductive tracts, compared to inactive steroidogenic organs, ovaries from non-blood-fed females. Some genes encoding P450 enzymes were specifically overexpressed in female ovaries after a blood-meal or in male reproductive tracts but only three genes were found to be overexpressed in active steroidogenic organs of both females and males: cyp307a1, cyp4g16 and cyp6n1. Among these genes, only cyp307a1 has an expression pattern similar to other mosquito steroidogenic genes. Moreover, loss-of-function by transient RNAi targeting cyp307a1 disrupted ecdysteroid production demonstrating that this gene is required for ecdysteroid biosynthesis in Anopheles gambiae.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

We explain the choice between franchising and vertical integration by estimating a model of relative performance in a sample of 250 Spanish car distributors, controlling for self-selection and including environmental factors. The method allows us to estimate performance counterfactuals. Organizational choice seemingly aims to contain moral hazard for both distributors and manufacturers but it is subject to start-up constraints and switching costs. While the market for franchises remained underdeveloped, information asymmetries led to the opening of integrated outlets. Their subsequent conversion into franchised outlets probably involved prohibitive transaction costs. Consequently, they performed worse than would have been expected had they been independent, as confirmed by the systematic improvement observed when they were in fact converted. The timing of such conversions suggests that switching costs were prohibitive until firms developed a substantial cushion of temporary contracts, previously forbidden by regulation.