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PubMedDate not supplied

The demography, career pattern, and motivation of locum tenens physicians in the United States.

The objective of this study was to provide a profile of locum tenens providers and their motivation for choosing this practice pattern. The research design used was a cross-sectional mailed survey questionnaire. Participants included the 1662 physicians who accepted at least one locum tenens assignment in 2001 from one physician staffing service. They were asked to complete a 50-element questionnaire; 776 (47 percent) responded. The average age of respondents was 53.0 years. Men represented 70.3 percent of the sample and were significantly older (56.3 years) than women providers who responded (45.3 years). One-third considered a locum tenens practice pattern permanent. Primary care locums were younger than specialists and subspecialists. Female providers were disproportionately practicing in primary care specialties (43.9 percent); 64 percent used locum income as their sole source of support and were frequently (31 percent) motivated by a need for a flexible work schedule. Male locum physicians were weighted toward the subspecialties and were motivated mostly (62 percent) by a desire to continue to practice part time. They used locum income as a secondary means of support (33 percent) or to augment pension and retirement resources (38 percent). A physician workforce from most major specialties and subspecialties and all age groups and career stages fulfills career and economic goals by working in a short-term, temporary employment pattern. Locum tenens appeals to physician providers who desire a healthier, more controllable lifestyle.

Adult↗
PubMed2005

Phylogeography and demography of sympatric sister surfperch species, Embiotoca jacksoni and E. lateralis along the California coast: historical versus ecological factors.

With 18 closely related endemic species that radiated in a diversity of ecological niches, the California surfperches (Embiotocidae) species flock is a good candidate for the study of sympatric speciation. Resource partitioning has been suggested as an important driving force in the radiation of the surfperch family. Within the family, two congeneric sister species, Embiotoca jacksoni and E. lateralis, are known to compete strongly for a preferred single food resource and may be used as a model of ecological interactions for the family. Along the California coast, the distribution of the two species differs. Embiotoca jacksoni has a continuous range, whereas E. lateralis shows a disjunction with a distribution gap in the Southern California Bight. Two hypotheses may explain this disjunct distribution. Ecological competition may have displaced E. lateralis in favor of E. jacksoni. Alternatively, a common vicariant event may have separated the species into northern and southern populations, followed by secondary contact in E. jacksoni but not in E. lateralis. The two hypotheses predict different phylogeographic and demographic signatures. Using a combined phylogeographic and coalescent approach based on mitochondrial control region data, we show that vicariance can only account for a portion of the observed divergences. Our results are compatible with a significant role played by ecological competition in the southern range of the species.

Animals↗
PubMed2005

Profile of graduates of Israeli medical schools in 1981--2000: educational background, demography and evaluation of medical education programs.

BACKGROUND: In light of changes in the medical profession, the different requirements placed on physicians and the evolving needs of the healthcare system, the need arose to examine the medical education curriculum in Israel. This survey, conducted by the Samuel Neaman Institute for Science and Technology, summarizes 20 years of medical education in Israel's four medical schools, as the first stage in mapping the existing state of medical education in Israel and providing a basis for decision-making on future medical education programs. OBJECTIVES: To characterize the academic background of graduates, evaluate their attitudes towards current and alternative medical education programs, and examine subgroups among graduates according to gender, medical school, high school education, etc. METHODS: The survey included graduates from all four Israeli medical schools who graduated between the years 1981 and 2000 in a sample of 1:3. A questionnaire and stamped return envelope were sent to every third graduate; the questionnaire included open and quantitative questions graded on a scale of 1 to 5. The data were processed for the entire graduate population and further analyzed according to subgroups such as medical schools, gender, high school education, etc. RESULTS: The response rate was 41.3%. The survey provided a demographic profile of graduates over a 20 year period, their previous educational and academic background, additional academic degrees achieved, satisfaction, and suggestions for future medical education programs. CONCLUSIONS: The profile of the medical graduates in Israel is mostly homogenous in terms of demographics, with small differences among the four medical schools. In line with recommendations of the graduates, and as an expression of the changing requirements in the healthcare system and the medical profession, the medical schools should consider alternative medical education programs such as a bachelor's degree in life sciences followed by MD studies, or education programs that combine medicine with disciplines such as law, engineering, computer science, among others.

Adult↗
PubMed2005

Genealogical footprints of speciation processes in wild tomatoes: demography and evidence for historical gene flow.

Multilocus studies assessing patterns of nucleotide polymorphism within and among closely related species provide access to genealogical information bearing on demographic and geographic aspects of their speciation history. However, the technical difficulties in obtaining sufficient sequence data have severely limited this approach thus far, especially in outbred plant taxa. We employ the analytical framework of divergence population genetics in testing the isolation model of speciation in three self-incompatible species of wild tomatoes (clade Lycopersicon), in particular the assumption of divergence without gene flow. Based on DNA sequence data for 13 nuclear loci, average levels of silent polymorphism vary more than three-fold among species. We estimate a large effective population size for the ancestral species, quite similar to that of the highly polymorphic L. peruvianum. The other two species, however, exhibit concordant signatures of population-size reduction. These demographic inferences are biologically plausible and consistent with results obtained from standard neutrality tests. While the isolation model cannot be rejected by goodness-of-fit criteria, patterns of intragenic linkage disequilibrium in L. peruvianum are indicative of historical introgression at least in some regions of the genome. Considered jointly with the geographic pattern of postzygotic reproductive isolation, our results suggest that speciation occurred under residual gene flow, implying natural selection as one of the evolutionary forces driving the diversification of tomato lineages.

Base Sequence↗
PubMed1992

The magnitude and origin of European-American admixture in the Gila River Indian Community of Arizona: a union of genetics and demography.

Complementary genetic and demographic analyses estimate the total proportion of European-American admixture in the Gila River Indian Community and trace its mode of entry. Among the 9,616 residents in the sample, 2,015 persons claim only partial Native American heritage. A procedure employing 23 alleles or haplotypes at eight loci was used to estimate the proportion of European-American admixture, m(a), for the entire sample and within six categories of Caucasian admixture calculated from demographic data, md. The genetic analysis gave an estimate of total European-American admixture in the community of 0.054 (95% confidence interval [CI] .044-.063), while an estimate from demographic records was similar, .059. Regression of m(a) on md yielded a fitted line m(a) = .922md, r = .959 (P = .0001). When total European-American admixture is partitioned between the contributing populations, Mexican-Americans have provided .671, European-Americans .305, and African-Americans .023. These results are discussed within the context of the ethnic composition of the Gila River Indian Community, the assumptions underlying the methods, and the potential that demographic data have for enriching genetic measurements of human admixture. It is concluded that, despite the severe assumptions of the mathematical methods, accurate, reliable estimates of genetic admixture are possible from allele and haplotype frequencies, even when there is little demographic information for the population.

Alleles↗
PubMed2005

[Genetic demography of the Kuznetsk Basin population: changes in marriage assortativeness with respect to ethnicity and age in the Belovo city population with time].

A genetic demographic study has been performed in the city of Belovo with the use of the data on marriages contracted there in 1970 and 1994-1999. Marriage assortativeness with respect to age has been found to be the strongest and remain unchanged during the lifetime of one generation (r = 0.730 in 1970 and r = 0.801 in 1994-1999). Monoethnic marriages were substantially more frequent than interethnic ones in the Belovo population during the period studied, although the ethnic marriage assortativeness considerably decreased (K = 0.386 in 1970 and K = 0.141 in 1994-1999). Panmixia has been observed in the Russian population of Belovo. Other Eastern Slavs (Ukrainians and Belarussians) are characterized by negative marriage assortativeness and panmixia; positive marriage assortativeness has been found in other ethnic groups.

Age Distribution↗
PubMed1991

The dynamics of population aging: demography and policy analysis.

The dynamics of population aging will broadly shape future social and economic conditions in the United States and in many other developed countries. Although the quantitative dimension of population aging is easily characterized, the associated forces producing changes in health and functioning among individuals are less well understood. For 14 years the Milbank Quarterly, under the editorship of David Willis, fostered research into the interaction of demographic, epidemiological, public health, and clinical factors in order better to understand population aging. The Quarterly spurred the collection of longitudinal data, based on representative samples of the U.S. elderly and oldest-old populations, which were crucial to efforts to answer critical questions about anticipated changes in health and functional status as the population ages. This research will give us a better grasp of the policy and service implications of an aging population.

Activities of Daily Living↗
PubMed1991

Older Rhode Islanders: demography, health status and the implications for the practice of medicine.

There is a large and growing elderly population in Rhode Island and that population is getting older. Rhode Island's elders are maldistributed geographically and represent a larger proportion of the population than nationally. Most have significant chronic conditions and many have major limitations in functional abilities. Relatively few reside in long-term care facilities and generally, the community-dwelling population rates their health favorably. The elderly in Rhode Island make more physician visits than any other segment of the population and account for a disproportionate number of hospital and nursing home days. The number of primary care physicians practicing adult medicine in Rhode Island has diminished and if the trends of graduating medical students continue, further decreases are to be expected. The costs of health care for the elderly in Rhode Island have skyrocketed over the last 20 years, and are projected to continue to increase dramatically over the next 40-50 years in part as a result in the growth of the state's elderly population. These cost increases will be magnified if health care costs in general continue to outpace other segments of our economy. If Rhode Island is to adequately meet the health care needs of older Rhode Islanders over the next 40-50 years, major changes must occur. Initiatives to prevent or forestall the onset of chronic illnesses and resultant functional limitations are likely to improve the quality of life of older Rhode Islanders as well as positively influence the costs of health care for this segment of our state's population.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

[Demography: an irreplaceable and unrecognized discipline].

In this introduction to demographic analysis the author emphasises the role of the population structure (sex and age distribution) resulting from the interplay and changes of demographic factors (births, deaths, migrations). Examples are given of errors to be avoided in the interpretation of demographic data, the apparent simplicity of which may be misleading.

Age Factors↗
PubMed1988

Multinomial and conditional logit discrete-choice models in demography.

Although discrete-choice statistical techniques have been used with increasing regularity in demographic analyses, McFadden's conditional logit model is less well known and seldom used. Conditional logit models are appropriate when the choice among alternatives is modeled as a function of the characteristics of the alternatives, rather than (or in addition to) the characteristics of the individual making the choice. We argue that this feature of conditional logit makes it more appropriate for estimating behavioral models. In this article, the conditional logit model is presented and compared with the more familiar multinomial logit model. The difference between the two techniques is illustrated with an analysis of the choice of marital and welfare status by divorced or separated women.

Adult↗