Population and land use change in the California Mojave: Natural habitat implications of alternative futures

Demographic and land use dynamics have important implications for the natural environment within both developed and developing nations. Within the context of developed nations, popular and policy debates surrounding contemporary patterns of suburbanization attest to the salience of demographic and development issues. We examine the implications of land-use patterns as related to population and development within the context of the California Mojave Desert ecosystem. In a general sense, we aim to better understand the land requirements inferred by varying levels of population growth and density, as well as the natural habitat implications of those requirements. We develop a GIS including remotely sensed imagery, and demographic, economic, and biophysical data to examine of the implications of various demographic scenarios on species diversity. Spatial and statistical models are designed to develop possible alternative land use `futures'. Within the context of the California Mojave region, our results suggest that high-density development could reduce conflict with regions providing potential habitat for threatened or endangered species by over 80 percent. The process of model development demonstrates a potentially useful tool for policymakers, allowing for estimation and visualization of the land use implications of policy decisions.     

Factorial ecology: A critique and some suggestions

Studies in factorial ecology have typically used the principal factor procedure coupled with varimax rotation. Since it can be shown that the results one obtains vary according to the factor and rotation models he employs, and since there is no one “best” way of obtaining initial and derived factor solutions, it is proposed that future research in the area adopt an approach involving the simultaneous use of several different computing algorithms for obtaining initial solutions and both orthogonal and oblique rotation procedures to avoid the possibility that the results one obtains are not method-dependent. Ideally, the factor models employed should differ maximally with respect to the principles upon which they are based. If one finds a given factor regardless of the method he uses, only then can he assert with any confidencethat it is not an artifact of his method. Factorial ecologists are often interested in computing “factor scores”, but “true” factor scores are not uniquely computable; they can only be estimated. Since the proposed research strategy involves using either a component or an image model, in which the corresponding scores are exact and uniquely computable, the factor score problem is, in a sense, solved. Next it is suggested that, by using orthogonal solutions, factorial ecologists may be overlooking a very important piece of information—the correlation between the factors. There is some reason to believe that this varies from city to city, and may account for the fact that some factors which emerge in studies of Western cities are sometimes not found in cities elsewhere. Some comments are also made on the value of using census tract data, and on the availability of computer programs for different initial and derived factor solutions.     

The Effects of Post-marital Childbearing on Divorce and Remarriage: An Application of Hazards Models with Time-dependent Covariates

In this paper we examine the effects of having a baby during a period of separation on the probability of divorce, and the impact of bearing a child while divorced on the likelihood of remarriage in the United States. Among whites, neither a first nor a second birth during separation had any significant effect on the probability of divorce. Among blacks, either a first or second birth significantly increased the chance of divorce. The function of post-marital childbearing among black women as an incentive to obtaining divorces (presumably to allow them to establish new unions formally) is important, because a large proportion remain separated indefinitely. Whereas the occurrence of both first and second births during divorce significantly increased the probability of remarriage among whites, only a second birth did so among blacks. Further analysis suggests that while the legitimization of births was an important factor among whites, there was little evidence of a comparable effect among blacks.     

The labour supply of Indigenous Australian females: the effects of fertility and interactions with the justice system

Indigenous females are among the most disadvantaged groups in Australia; Furthermore outcomes for Indigenous Australians compare unfavourably with those for similar First Nations around the world. There appears to be a demographic transition under way in Indigenous Australia whereby declines in fertility and mortality are likely to lead to an increase in the number of Indigenous people supplying their labour in the near future. This paper examines the determinants of Indigenous female labour force participation with a particular focus on the role of fertility and interaction with the justice system. The analysis controls for the standard determinants of labour supply, but its main contribution is in taking into account the endogeneity of these potential interruptions to labour market participation. These findings are also important because Indigenous Australian females are 22 times more likely to be in prison than other Australian females and hence the analysis has crucial implications for the ability of policy makers to ‘close the gaps’ between Indigenous and other Australians. Once endogeneity of fertility with labour supply is taken into account, there is no significant independent effect on labour force participation and hence policy should focus on the other factors including education and training.     

Understanding intimate partner violence against women in the rural South

Most U.S. intimate partner violence (IPV) research to date has been limited to women residing in urban areas, with the small body of research focusing on rural populations being primarily qualitative. In this case-control study of Southern rural women, while many factors are consistent with those found in urban settings, unlike findings elsewhere, IPV risk appears to increase with age, and race showed no increased risk. Furthermore, in rural areas where guns are more acceptable than in other parts of the United States, partners of IPV victims are considerably more likely to carry weapons than partners of nonabused women. Given the geographic limitations to police and medical response to severe IPV in a rural setting, an improved understanding of IPV risk among this population can aid health care providers in ascertaining risk before it escalates further.     

A prospective examination of depression,anxiety and stress throughout pregnancy

BackgroundPerinatal distress has largely been conceptualised as the experience of depression and/or anxiety. Recent research has shown that the affective state of stress is also present during the perinatal period and thus may add to a broader understanding of perinatal distress.AimThe aims of the present study were to investigate the changes in depression, anxiety and stress symptoms across pregnancy, and to explore the prospective relationships between these symptoms.MethodsTwo-hundred and fourteen pregnant women were recruited when they were less than 16 weeks gestation. Women completed depression, anxiety and stress measures on a monthly basis, from 16 weeks gestation through to 36 weeks gestation. The covariate measures of sleep quality and social support were assessed bi-monthly at 16, 24 and 32 weeks gestation.FindingsLevels of depression, anxiety and stress symptoms were all shown to change over time, with women experiencing fewer symptoms during the middle of their pregnancy. Higher symptoms early in pregnancy predicted higher symptom levels throughout the rest of pregnancy. Higher depression scores early in pregnancy were also shown to predict higher anxiety and higher stress scores in late pregnancy. Increased stress scores during mid pregnancy also predicted higher anxiety scores in late pregnancy.ConclusionCurrent findings indicate that symptom levels of depression, anxiety and stress vary over the course of pregnancy. Increased depression in early pregnancy seemed to be particularly pertinent as it not only predicted later depression symptoms, but also increased anxiety and stress in late pregnancy. Collectively, these results further highlight the importance of emotional health screening early in pregnancy.     

The transition to motherhood: Towards a broader understanding of perinatal distress

BackgroundA substantial body of research has focused on maternal perinatal mood and wellbeing, with the focus predominantly being on depression, and to a lesser extent, anxiety. Perinatal maternal stress has also been investigated recently, but to a far lesser extent. The present paper questions whether the term ‘perinatal distress’ accurately captures the range of challenges experienced by women during the perinatal period, when the scope of ‘distress’ is limited to the experience of depression and anxiety alone.MethodA review of the perinatal literature was conducted using several databases, to identify studies that have focused on the experience of stress as a distinct affective state in the perinatal period.FindingsThe findings of two recent studies which have employed a broader conceptualisation of perinatal distress to encompass the experience of stress as well as depression and anxiety are outlined. These recent studies have identified the experience of stress both in conjunction with and independent of depression and anxiety.ConclusionIt is argued that future studies should investigate the concept of stress as a separate affective state throughout the perinatal period, in order to further assess how it differs from depression and/or anxiety. A more comprehensive understanding of women's experiences during their transition to motherhood, and whether ‘stress’ plays a critical role in the development and maintenance of perinatal anxiety and/or depression is needed.