140 resultados para transition forest
Resumo:
The occurrence of cardiovascular diseases (CVD) and related risk factors was evaluated in Seychelles, a middle level income country, as accumulating evidence supports increasing rates of CVD in developing countries. CVD mortality was obtained from vital statistics for two periods, 1984-5 and 1991-3. CVD morbidity was estimated by retrospective review of discharge diagnoses for all admissions to medical wards in 1990-1992. Levels of CVD risk factors in the population were assessed in 1989 through a population-based survey. In 1991-93, standardized mortality rates were in males and females respectively, 80.9 and 38.8 for cerebrovascular disease and 92.9 and 47.0 for ischemic heart disease. CVD accounted for 25.2% of all admissions to medical wards. Among the general population aged 35-64, 30% had high blood pressure, 52% of males smoked, and 28% of females were obese. These findings substantiate the current health transition to CVD in Seychelles. More generally, epidemiologic data on CVD mortality, morbidity, and related risk factors, as well as similar indicators for other chronic diseases, should more consistently appear in national and international reports of human development to help emphasize, in the health policy making scene, the current transition to chronic diseases in developing countries and the subsequent need for appropriate control and prevention programs.
Resumo:
In sharp contrast to birds and mammals, most cold-blooded vertebrates have homomorphic (morphologically undifferentiated) sex chromosomes. This might result either from recurrent X-Y recombination (occurring e.g. during occasional events of sex reversal) or from frequent turnovers (during which sex-determining genes are overthrown by new autosomal mutations). Evidence for turnovers is indeed mounting in fish, but very few have so far been documented in amphibians, possibly because of practical difficulties in identifying sex chromosomes. Female heterogamety (ZW) has long been established in Bufo bufo, based on sex reversal and crossing experiments. Here, we investigate a sex-linked marker identified from a laboratory cross between Palearctic green toads (Bufo viridis subgroup). The F(1) offspring produced by a female Bufo balearicus and a male Bufo siculus were phenotypically sexed, displaying an even sex ratio. A sex-specific marker detected in highly reproducible AFLP genotypes was cloned. Sequencing revealed a noncoding, microsatellite-containing fragment. Reamplification and genotyping of families of this and a reciprocal cross showed B. siculus to be male heterogametic (XY) and suggested the same system for B. balearicus. Our results thus reveal a cryptic heterogametic transition within bufonid frogs and help explain patterns of hybrid fitness within the B. viridis subgroup. Turnovers of genetic sex-determination systems may be more frequent in amphibians than previously thought and thus contribute to the prevalence of homomorphic sex chromosomes in this group.
Resumo:
Les travaux qui se sont intéressés à l'hypothèse des avantages et désavantages cumulatifs (ADC) dans la perspective du parcours de vie montrent comment, au sein d'une même cohorte, des différences initiales pour une caractéristique déterminée (sexe, statut social, santé) contribuent à structurer des trajectoires de vie différenciées. La plupart de ces études se concentrent sur l'empan de vie sans mesurer l'effet que des transitions particulières jouent dans ce processus. Dans cet article nous nous centrons sur la transition à la parentalité pour montrer que le type d'insertion professionnelle des partenaires avant cette transition explique la différenciation subséquente de leurs trajectoires professionnelles. Abstract Life course studies focusing on the cumulated advantages and disadvantages (CAD) hypothesis indicate that initial differences in a specific characteristic (sex, social status, or health) have an impact on intracohort differentiation. Most of these studies consider an entire life course and do not focus on specific transitions as a key moment for differentiation. In this article, the researchers focus on the transition to parenthood, showing that variations in occupational participation of both partners before the birth of a first child explain how professional trajectories differentiate after the birth of the child. Zusammenfassung Die Arbeiten, die sich für die Hypothese der kumulierten Vor- und Nachteile in einer Lebenslaufperspektive interessiert haben, zeigen, wie anfängliche Unterschiede bezüglich bestimmter Charakteristiken (Geschlecht, sozialer Status, Gesundheit) innerhalb einer Kohorte zur Strukturierung unterschiedlicher Lebensläufe beitragen. Die meisten dieser Studien konzentrieren sich auf den Gesamtlebenslauf, ohne die Effekte spezifischer biographischer Übergänge zu messen. In diesem Artikel beschränken wir uns auf den biographischen Übergang zur Elternschaft. Wir zeigen auf, wie die Erwerbssituation der Partner vor diesem Übergang die nachfolgende Differenzierung ihrer Berufsverläufe beeinflusst.
Resumo:
We find that even very low Ni doping levels of high-quality Bi2Sr2Ca1Cu2O8 single crystals strongly affect the transition temperature T(c). We also observed that T(c) is not related to the total Ni concentration, but only to that of Ni engaged in NiO-type bonds. By controlling the temperature during crystal growth, one can modify the relative weight of Ni in NiO-type bonds with respect to other configurations-and therefore T(c).
Life Markers of the transition to adulthood. A first investigation of Traces LifeCourse Events data.
Resumo:
In Europe, Switzerland presents an unusual pattern of marriage with a very high proportion of couples who begin to cohabit without being married, but with a very low proportion of nonmarital births. A lot of couples marry before the conception of the child or during the pregnancy. In this article we focus on the point of view of men vis-agrave-vis the marriage and its meanings. Qualitative investigations show that men strongly desire marriage for several reasons, from their desire to participate in child rearing to the fear of having their paternity denied by Swiss institutions