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Age Composition (age + composition)
Selected AbstractsTHE SOCIAL ECOLOGY OF VIOLENCE AGAINST WOMEN,CRIMINOLOGY, Issue 2 2004JANET L. LAURITSEN Despite more than three decades of research on the topic of violence against women, the relative contribution of individual, family and community factors to victimization risk remains unknown. We use self-report data from the Area-Identified National Crime Victimization Survey to study the correlates of stranger, nonstranger and intimate,partner violence against women. Regardless of victim-offender relationship, we find that the risk for victimization is highest among young, single women with children, particularly those who have lived in the current home for relatively shorter periods. Area family and age composition appear to have stronger direct relationships with women's violence than poverty or racial composition measures. We also find there to be more similarities than differences in the individual, family, and community correlates of stranger, nonstranger and intimate partner violence. We discuss these findings as part of the growing body of multilevel literature on violence and on violence against women. [source] Seasonal changes in abundance and age structure of burbot Lota lota (L.) and stone loach Barbatula barbatula (L.) in the littoral zone of a large pre-alpine lakeECOLOGY OF FRESHWATER FISH, Issue 1 2001N. Hofmann Abstract , Seasonal changes in the abundance and age structure of the stone loach and burbot populations in the littoral of Lake Constance, Germany were examined. The abundance of both species was lowest during the summer months and highest during autumn. The stone loach population in the littoral comprised age classes 1 to 3 plus, in autumn, age class 0. The burbot population showed distinct seasonal changes in both length and age composition. During spring and summer, only age class 1 was present in the littoral whereas, in autumn, only age class 0 was caught. This remarkably strict habitat segregation of two age classes by season is discussed with respect to a possible mechanism for avoiding conspecific predator risk in a cannibalistic species. [source] Term premia and the maturity composition of the Federal debt: new evidence from the term structure of interest ratesJOURNAL OF FORECASTING, Issue 7 2001Basma Bekdache Abstract This paper models bond term premia empirically in terms of the maturity composition of the federal debt and other observable economic variables in a time-varying framework with potential regime shifts. We present regression and out-of sample forecasting results demonstrating that information on the age composition of the Federal debt is useful for forecasting term premia. We show that the multiprocess mixture model, a multi-state time-varying parameter model, outperforms the commonly used GARCH model in out-of-sample forecasts of term premia. The results underscore the importance of modelling term premia, as a function of economic variables rather than just as a function of asset covariances as in the conditional heteroscedasticity models. Copyright © 2001 John Wiley & Sons, Ltd. [source] Social structure of a polygynous tent-making bat, Cynopterus sphinx (Megachiroptera)JOURNAL OF ZOOLOGY, Issue 2 2000Jay F. Storz Abstract The social structure of an Old World tent-making bat Cynopterus sphinx (Megachiroptera), was investigated in western India. A combination of census and mark,recapture data over 2 years (1996,98) was used to infer the form of the mating system, compositional stability of social groups and mode of new social group formation. The breeding population of C. sphinx was subdivided into diurnal roosting colonies, each of which contained one to five discrete roosting groups and often one or more solitary bats in adjacent roosts. Bats most frequently roosted in stem tents constructed in the flower/fruit clusters of the kitul palm Caryota urens. Temporal variation in social structure was assessed using visual census data for a subset of the study population over 3 years (1995,98) spanning six consecutive reproductive periods. The sex and age composition of diurnal roosting groups indicated a polygynous harem-forming mode of social organization, as groups invariably contained a single adult male, 1,37 reproductive females and their dependent young (n= 33 harems). Harem size averaged 6.1 adults in the wet season (n= 19, sd= 3.5) and 13.6 adults in the dry season (n= 14, sd= 8.5). The same harem social configuration was maintained year-round, despite a high degree of synchrony and seasonality in the timing of reproduction. Juveniles of both sexes dispersed after weaning and sexually immature bats were never present in harems at the time of parturition. Adult females often remained associated as roostmates from one parturition period to the next, and group cohesion was unaffected by turnover of harem males. Adult females frequently transferred among roosts within the same colony, and harems underwent periodic fissions and fusions. The founding of new harems most often resulted from the fissioning of previously cohesive harems within the same colony. However, some harems contained disproportionate numbers of yearling females, indicating that new groups are also founded by nulliparous females of the same age cohort. A significant degree of heterogeneity in age composition among harems was revealed in the 1998 dry season, but was unrelated to age-stratification of tent roosts. Although formation of new harems may be non-random with respect to age composition of the founders, founding events are not restricted to newly created tents and often involve recolonization of previously occupied roosts. [source] What can the age composition of a population tell us about the age composition of its out-migrants?POPULATION, SPACE AND PLACE (PREVIOUSLY:-INT JOURNAL OF POPULATION GEOGRAPHY), Issue 1 2007Jani S. Little Abstract Preliminary findings show that the age structure of a population can provide valuable information about the age composition of its out-migrants, and that this relationship can become a key ingredient in the proposed new method for estimating the age profile of out-migrants when accurate data are not available. The method relies on the Rogers-Castro model schedule to consistently and accurately represent age profiles of out-migration, and the results show that variation among these out-migration schedules can be captured by a typology based on a small set of clusters, or families of schedules. Membership of the clusters is then predicted from simple measures of population composition using discriminant function analysis. The investigation is based on data for US states, CMSAs, MSAs and non-metropolitan counties, and their outflows of migrants between 1995 and 2000. The measures of population age composition come from official 1995 intercensal age-specific population estimates for the same geographical units. Copyright © 2007 John Wiley & Sons, Ltd. [source] A Box,Cox Double-hurdle ModelTHE MANCHESTER SCHOOL, Issue 2 2000Andrew M. Jones The double-hurdle model with dependence is extended by incorporating the Box,Cox transformation. The model nests a range of popular limited dependent variable models, including the Gaussian double-hurdle, the generalized Tobit, and two-part models. Estimates of US beef consumption suggest that the Box,Cox specification outperforms all other restrictive models. Price elasticities are small and similar to findings in the literature. Household age composition and demographic variables also play significant roles in determining beef consumption. Income and cross-price elasticities are insignificant. [source] Growth and reproductive biology of the foxfish Bodianus frenchii, a very long-lived and monandric protogynous hermaphroditic labridJOURNAL OF FISH BIOLOGY, Issue 3 2010S. Cossington Samples of the foxfish Bodianus frenchii, collected over reefs on the lower west and south coasts of Western Australia, contained individuals ranging up to 78 years old. Although B. frenchii is far smaller than many other species within the Labridae, its maximum age is the greatest yet recorded for this highly speciose family and, together with Achoerodus gouldii, provides an example of a temperate hypsigenyine with exceptional longevity. Length and age compositions of females and males and the histological characteristics of gonads of a wide length range of individuals demonstrated that B. frenchii is a protogynous hermaphrodite. Furthermore, as, on both coasts, the length of the smallest male was greater than that at which all females had become mature, B. frenchii is a monandric protogynous hermaphrodite, i.e. all of its males are derived from functional females. Attainment of maturity by females is related more to length than age, whereas the reverse is true for sex change. On the basis of Schnute growth equations and length-to-body mass regression equations, the predicted length at age and body mass at length of fish on the south coast were greater than those on the west coast throughout life. Although B. frenchii spawns daily during the main spawning season, which extends from October to February on both coasts, its fecundity at any given length is substantially greater on the south than on the west coast. The more rapid growth of juveniles and earlier attainment of maturity by B. frenchii on the south coast than on the warmer west coast, together with maturation at a similar size on both coasts, run counter to the trends observed in many species and certain ecological theories regarding the relationships between life-cycle traits and latitude and temperature. The attainment by B. frenchii of a larger body length at age, of greater body mass at length and of greater fecundity at both length and body mass in fish on the south than on the west coast strongly suggests that conditions on the former, cooler coast are more favourable for this labrid, which belongs to a sub-genus whose other species typically live in cool, deep, temperate waters. [source] Age and size compositions, growth and reproductive biology of the breaksea cod Epinephelides armatus, a gonochoristic serranidJOURNAL OF FISH BIOLOGY, Issue 5 2007S. E Moore Details of the reproductive biology, size and age compositions and growth of the breaksea cod Epinephelides armatus, the sole representative of Epinephelides, were obtained by collecting monthly samples of a wide total length (LT) range of individuals from coastal marine waters at 31,32° S on the lower west coast of Australia. Although the modal LT class of females (250,299 mm) was markedly less than that of males (400,449 mm), the modal ages of the two sexes were similar, i.e. 4 v. 5 years, respectively. The similarity in the age compositions and the histological demonstration that the gonads of all E. armatus consist solely of either ovarian or testicular tissues demonstrate that this species is gonochoristic, which is highly unusual for an anthiinine serranid. The absence of a central, membrane-lined ,ovarian' lumen in the testes of juveniles would account for adult testes containing neither this ovarian remnant nor the peripherally located sperm sinuses that are found in the mature testes of almost all other serranids. The results demonstrate that E. armatus exhibits a very unusual pattern of sexual development for a serranid. The spawning period of E. armatus lasts for c. 9 months, which is long for a species in temperate Western Australian waters, but comparable with that of many other relatively small serranids elsewhere. Females grow slower than males, attaining LT at 3, 5 and 10 years of c. 200, 285 and 420 mm, respectively, compared with c. 215, 315 and 450 mm, respectively. Females, however, attain maturity at a greater LT and older age than males. [source] | |||||||||||||