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At least 937 records · Page 52Linked to original sources
PubMed1997

Modelling regional population growth in China.

"This paper develops a forward demographic rates-based multiregional population model on the basis of a set of multiregional population accounts. Forward emigration rates and immigration flows are adopted to describe the external migrations. The model is used to make consistent multiregional population projections of China at a provincial level.... Three sets of multiregional population projections of China at provincial level are made for the period 1987-2087. It is found that the national population trend is a combination of various regional population trends. Some regions, such as Zhejiang, will reach their population peak as early as the beginning of the next century while other regions, such as Xinjiang, will face continuous population growth in the first half of the next century."

Asia↗
PubMed1994

Illegal immigration in the presence of labor unions.

"This paper develops a general equilibrium framework of a two-sector economy which incorporates illegal immigration in the presence of labor unions. It demonstrates that stricter enforcement of immigration laws, by reducing the demand for or supply of illegal aliens, benefits all legal workers in the economy. The model is used to evaluate the impact of these policy changes on national income. Results indicate that national income does not necessarily fall when immigration controls are tightened. The existence of a union mitigates the negative welfare impact of a reduction in the number of illegal immigrants."

Demography↗
PubMed2001

Assessing culture via the Internet: methods and techniques for psychological research.

This study examines the acculturation experiences of Arabic immigrants and assesses the utility of the Internet as a data collection tool. Based on in-depth pilot interview data from 10 male Arabic immigrants and items selected from pre-existing measures, the Male Arabic Ethnic Identity Measure (MAEIM) was developed. Male Arab immigrants (115 males) were solicited through traditional methods in addition to the Internet. Satisfactory reliability and validity were reported for the MAEIM. No significant differences emerged between the Internet and Midwestern samples. The Internet proved to be an effective method for soliciting a relatively large, geographically dispersed sample of Arabic immigrants. The use of the Internet as a research tool is examined in the context of anonymity, networking, low-cost, perceived interactive control, methodological rigor, and external validity. The Internet was an effective vehicle for addressing concerns raised by prospective participants. It is suggested that the Internet may be an important method to assess culture-relevant variables in further research on Arab and other immigrant populations.

Acculturation↗
PubMed2001

Estimation of effective population size and migration rate from one- and two-locus identity measures.

Standard methods for inferring demographic parameters from genetic data are based mainly on one-locus theory. However, the association of genes at different loci (e.g., two-locus identity disequilibrium) may also contain some information about demographic parameters of populations. In this article, we define one- and two-locus parameters of population structure as functions of one- and two-locus probabilities for the identity in state of genes. Since these parameters are known functions of demographic parameters in an infinite island model, we develop moment-based estimators of effective population size and immigration rate from one- and two-locus parameters. We evaluate this method through simulation. Although variance and bias may be quite large, increasing the number of loci on which the estimates are derived improves the method. We simulate an infinite allele model and a K allele model of mutation. Bias and variance are smaller with increasing numbers of alleles per locus. This is, to our knowledge, the first attempt of a joint estimation of local effective population size and immigration rate.

Alleles↗
PubMed1997

Screening immigrants for tuberculosis in Newcastle upon Tyne.

BACKGROUND: Successive national guidelines on the control of tuberculosis in the United Kingdom have included recommendations for screening immigrants coming from countries with a high prevalence of tuberculosis. As there has been only one other study on the process and outcome of screening immigrants at a district level the aim of this study was to assess the contribution of screening immigrants to the control of tuberculosis in Newcastle. METHODS: The Port of Arrival (POA) forms were used to identify all new immigrants for screening in Newcastle during 1993. The Family Health Services Authority (FHSA) register was used to identify additional new immigrants from the Indian sub-continent. For all new immigrants identified by the POA forms and FHSA register, hospital and practice records were reviewed for evidence of screening and its outcome up to the end of 1994. RESULTS: There were 252 POA forms in 1993, 100 of which were for immigrants from the Indian sub-continent. This represents less than a third of all new immigrants from the Indian sub-continent. Of all immigrants identified by POA forms, 99 (39 per cent) had been screened. This resulted in the detection of one active case of tuberculosis. CONCLUSIONS: The POA system alone is inadequate for identifying immigrants for screening. The published evidence on screening immigrants for tuberculosis suggests that the system does not work well and the yield of new cases is low. To assess the effectiveness of screening immigrants a national audit is needed.

Emigration and Immigration↗
PubMed1995

Time trends in schizophrenia: changes in obstetric risk factors with industrialization.

The frequency of schizophrenia may have increased during the early stages of industrialization and may now be declining. Early in the process of development, the illness appeared to be more common among the upper classes and later, more common in the lower classes. As with certain other diseases, the occurrence of schizophrenia may be influenced by the transition from poverty to affluence. Explanations for such a pattern of occurrence include the combined effect of (1) variation in the rate of birth complications owing to cephalopelvic disproportion secondary to changes in nutrition, and (2) increased infant survival following improvements in obstetric and neonatal care. These effects help elucidate the pattern of occurrence of schizophrenia in immigrant groups.

Cross-Cultural Comparison↗
PubMed1995

Bovine tuberculosis in badger (Meles meles) populations in southwest England: the use of a spatial stochastic simulation model to understand the dynamics of the disease.

A spatial stochastic simulation model was developed to describe the dynamics of bovine tuberculosis in badger populations in southwest England, based on data from the literature and from unpublished sources. As there are no data on intra- and intergroup infection probabilities, estimates of these were obtained through repeated simulations based on field observations of the spread and prevalence of the disease. The model works on a grid-cell basis, with each grid cell potentially occupied by one badger social group; immigration to and emigration from the main grid are incorporated. Population regulation is assumed to occur at the group level through density-dependent fecundity and cub mortality, and the model can be run for various disease-free equilibrium group sizes (which are determined by the carrying capacity of the environment). The model works on a quarterly (three-monthly) basis and processes are stochastic at the individual level. Three classes of individual (adults, yearlings and cubs) and three classes of infection (susceptible, infected-but-not-infectious and infectious) are recognized. Bovine tuberculosis wa shown to persist in badger populations for long periods of time, even in populations with a disease-free equilibrium group size of only four adults and yearlings. However, with standard rates of intergroup infection and movement, the disease only became endemic in populations with a disease-free equilibrium group size greater than six adults and yearlings. In the endemic situation, the prevalence of the disease ranged between 11-22 degrees depending on the combination of inter- and intragroup infection probabilities used. Endemic infection within the homogeneous environment of the grid was characterized by a high degree of heterogeneity. Patches of infection were spatio-temporally unstable, but shifted in location relatively slowly. Spread of the disease from a point source of infection with standard rates of intergroup movement and infection only occurred to any marked extent in populations with disease-free equilibrium group sizes of eight or more adults and yearlings. Increasing the intergroup infection probability had a significant effect on increasing the probability and rate of spread, and considerably lowered the threshold group size for spread from a point source to around four adults and yearlings. However, increasing the rates of intergroup movement reduced the probability of spread of the disease except at the largest groups sizes. When both intergroup infection and movements were increased, the effects of increased infection in enhancing spread were offset to some degree by the increased movements. Perturbation to the badger population, as may be caused by control operations, could therefore increase the probability of persistence or spread of an infection.

Animals↗
PubMed1994

Assimilation and attachment in the context of international migration: the case of guestworkers in Germany.

"Immigrants' attachments to home and their assimilation into the host society have been identified as major factors influencing international return migration. This paper provides an empirical analysis of the determinants of attachment and assimilation, with a special focus on the impact of duration of stay. Using survey data on guestworkers in West Germany in 1984 and 1989, the study finds that assimilation increases at a decreasing rate as the duration of stay is extended. The relationship between attachment and length of stay is less strong, but shows a general trend of decreasing attachment levels as guestworkers prolong their stay in Germany. The resulting trends for return migration are characterized by an overall decline in the propensity to return as the duration of stay is extended. However, the rate of decline varies by gender, marital status, and nationality. Overall, the results allude to the importance of distinguishing between short term and long term immigrants."

Acculturation↗
PubMed1992

Hmong women: characteristics and birth outcomes, 1990.

Current demographic characteristics and pregnancy outcomes of immigrant Hmong women in a small town in southeastern United States were documented in a retrospective study. Interviews and review of existing records were used to determine prenatal practices and perceived problems. Sixteen health professionals and two women from the community were interviewed, and the labor and delivery records from 1985 to 1990 were reviewed for parity, child spacing, and health status of the women and newborns. The greatest concerns voiced by health caregivers were multiparity and the need for contraceptive compliance. Seventy-eight full-term infants were born to 64 women in five years, with 2 stillbirths. No eclampsia, diabetes, or Rh incompatibilities were noted. Evidence is limited that birth frequency or outcome for Hmong women is a problem. Their perinatal difficulties were thought to be sociocultural rather than medical. Further study of the effects of acculturation on maternal family position, perinatal risks, and birth outcomes is imperative as lifestyle and environment change for these immigrant women.

Adolescent↗