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Obstetrics in family medicine: effects on physician work load, income, and age of practice population.

A survey of active members of the American Academy of Family Physicians was conducted to determine the effect of the practice of obstetrics by family physicians on patient age distribution, physician work load, and physician income. A questionnaire was mailed to 800 randomly selected physicians; the survey response rate was 60.4%. Almost 20% of all respondents had never provided obstetrical care of any type. Another 40% had provided obstetrics previously but had discontinued this service, while the remaining 40% currently provided obstetrical care. Physicians who provided obstetrical services reported a significantly higher mean proportion of children and a significantly lower proportion of middle-aged and elderly adults in their patient panels than did physicians who do not provide obstetrics. Those physicians who had never offered obstetrics saw approximately the same number of patients and worked approximately the same number of hours as did those who provided low-risk, routine obstetrics; however, the former group reported a significantly higher average annual income than did the latter group.

Adolescent↗
PubMed1992

Who pays for health care in the United States? Implications for health system reform.

This paper examines the distribution of health care spending and financing in the United States. We analyze the distribution of employer and employee contributions to health insurance, private nongroup health insurance purchases, out-of-pocket expenses, Medicaid benefits, uncompensated care, tax benefits due to the exemption of employer-paid health benefits, and taxes paid to finance Medicare, Medicaid, and the health benefit tax exclusion. All spending and financing burdens are distributed across the U.S. population using the Urban Institute's TRIM2 microsimulation model. We then examine the distributional effects of the U.S. health care system across income levels, family types, and regions of the country. The results show that health care spending increases with income. Spending for persons in the highest income deciles is about 60% above that of persons in the lowest decile. Nonetheless, the distribution of health care financing is regressive. When direct spending, employer contributions, tax benefits, and tax spending are all considered, the persons in the lowest income deciles devote nearly 20% of cash income to finance health care, compared with about 8% for persons in the highest income decile. We discuss how alternative health system reform approaches are likely to change the distribution of health spending and financing burdens.

Adult↗
PubMed2005

A close-coupling study of vibrational-rotational quenching of CO by collision with hydrogen atoms.

Quantum-mechanical scattering calculations were performed for the rovibrational relaxation of CO in collisions with H atoms using the close-coupling approach for collision energies between 10(-6) and 1500 cm(-1). We adopted the H-CO interaction potential of Werner, Keller, and Schinke and computed the state-to-state and total cross sections for the quenching of the upsilon=1, j=0-2 levels of CO. Numerous resonances, as a consequence of the van der Waals potential, are observed and the cross sections are found to approach the Wigner limit at low energies. Also, by averaging the cross sections over a Boltzmann distribution of velocities of the incoming atom, quenching rate coefficients are obtained and found to be consistent with previous infinite-order sudden approximation calculations for temperatures between 100 and 300 K.

Journal Article↗
PubMed2000

A major susceptibility locus influencing plasma triglyceride concentrations is located on chromosome 15q in Mexican Americans.

Although several genetic forms of rare or syndromic hypertriglyceridemia have been reported, little is known about the specific chromosomal regions across the genome harboring susceptibility genes for common forms of hypertriglyceridemia. Therefore, we conducted a genomewide scan for susceptibility genes influencing plasma triglyceride (TG) levels in a Mexican American population. We used both phenotypic and genotypic data from 418 individuals distributed across 27 low-income, extended Mexican American families. For the analyses, TG values were log transformed (ln TG). We used a variance-components technique to conduct multipoint linkage analyses for localizing susceptibility genes that determine variation in TG levels. We used an approximately 10-15-cM map, which was made on the basis of information from 295 microsatellite markers. After accounting for the effects of sex and sex-specific age terms, we found significant evidence for linkage (LOD = 3.88) of ln TG levels to a genetic location between the markers GABRB3 and D15S165 on chromosome 15q. This putative locus explains 39.7+/-7% (P=.000012) of total phenotypic variation in ln TG levels. Suggestive evidence was found for linkage of ln TG levels to two different locations on chromosome 7, which are approximately 85 cM apart from each other. Also, there is some evidence for linkage of high-density lipoprotein cholesterol concentrations to a genetic location near one of the regions on chromosome 7. In conclusion, we found strong evidence for linkage of ln TG levels to a genetic location on chromosome 15q in a Mexican American population, which is prone to disease conditions such as type 2 diabetes and the insulin-resistance syndrome that are associated with hypertriglyceridemia. This putative locus appears to have a major influence on ln TG variation.

Adult↗
PubMed2004

Evidence of a novel quantitative-trait locus for obesity on chromosome 4p in Mexican Americans.

Although several genomewide scans have identified quantitative-trait loci influencing several obesity-related traits in humans, genes influencing normal variation in obesity phenotypes have not yet been identified. We therefore performed a genome scan of body mass index (BMI) on Mexican Americans, a population prone to obesity and diabetes, using a variance-components linkage analysis to identify loci that influence BMI. We used phenotypic data from 430 individuals (26% diabetics, 59% females, mean age +/- SD = 43 +/- 17 years, mean BMI +/- SD = 30.0 +/- 6.7, mean leptin (ng/ml) +/- SD = 22.1 +/- 17.1) distributed across 27 low-income Mexican American pedigrees who participated in the San Antonio Family Diabetes Study (SAFDS) for whom a 10-15-cM map is available. In this genomewide search, after accounting for the covariate effects of age, sex, diabetes, and leptin, we identified a genetic region exhibiting the most highly significant evidence for linkage (LOD 4.5) with BMI on chromosome 4p (4p15.1) at 42 cM, near marker D4S2912. This linkage result has been confirmed in an independent linkage study of severe obesity in Utah pedigrees. Two strong positional candidates, the human peroxisome proliferator-activated receptor gamma coactivator 1 (PPARGC1) and cholecystokinin A receptor (CCKAR) with major roles in the development of obesity, are located in this region. In conclusion, we identified a major genetic locus influencing BMI on chromosome 4p in Mexican Americans.

Body Mass Index↗
PubMed2006

Perceived quality of reproductive care for girls in a competitive voucher programme. A quasi-experimental intervention study, Managua, Nicaragua.

OBJECTIVE: To determine whether female adolescents from low-income areas in Managua were satisfied with the sexual and reproductive health (SRH) care provided through a competitive voucher programme and to analyse the determinants of their satisfaction. DESIGN: A community-based quasi-experimental intervention study from 2000 to 2002. SETTING: Low-income areas of Managua. INTERVENTION: Distribution of 28,711 vouchers giving adolescents free-access to SRH care in 19 clinics; training and support for health care providers. STUDY PARTICIPANTS: A random sample of 3009 girls from 12 to 20 years completed self-administered questionnaires: 700 respondents had used this care in the last 15 months, 221 with voucher (users-with-voucher) and 479 without voucher (users-without-voucher). MAIN OUTCOME MEASURES: User satisfaction; Satisfaction with clinic reception; Clarity of doctors' explanations. RESULTS: User satisfaction was significantly higher in users-with-voucher compared with users-without-voucher [Adjusted odds-ratio (AOR) = 2.2; 95% confidence interval (95% CI) = 1.2-4.0]. Voucher use was associated with more frequent satisfaction with clinic reception, especially among sexually active girls not yet pregnant or mother (AOR = 6.9; 95% CI = 1.5-31.8). The clarity of doctors' explanations was not perceived differently (AOR = 1.4; 95% CI = 0.9-2.2). User satisfaction was highly correlated to satisfaction with clinic reception and clarity of doctors' explanations (P < 0.001). Longer consultation times, shorter waiting times, older age, and having a female doctor positively influenced user satisfaction. CONCLUSION: Voucher use by teenage girls was associated with a better perceived SRH care. This is an important result, given the crucial role user satisfaction plays in adoption and continued use of health care and contraceptives. Though more research is needed, confidential and guaranteed access appear key factors to voucher success.

Adolescent↗
PubMed2006

Apis mellifera bees acquire long-term olfactory memories within the colony.

Early studies indicate that Apis mellifera bees learn nectar odours within their colonies. This form of olfactory learning, however, has not been analysed by measuring well-quantifiable learning performances and the question remains whether it constitutes a 'robust' form of learning. Hence, we asked whether bees acquire long-term olfactory memories within the colony. To this end, we used the bee proboscis extension response. We found that within-the-nest bees do indeed associate the odour (as the conditioned stimulus) with the sugar (as the unconditioned stimulus) present in the incoming nectar, and that the distribution of scented nectar within the colony allows them to establish long-term olfactory memories. This finding is discussed in the context of efficient foraging.

Animals↗
PubMed2004

Phase transitions in scale-free neural networks: departure from the standard mean-field universality class.

We investigate the nature of the phase transition from an ordered to a disordered state that occurs in a family of neural network models with noise. These models are closely related to the majority voter model, where a ferromagneticlike interaction between the elements prevails. Each member of the family is distinguished by the network topology, which is determined by the probability distribution of the number of incoming links. We show that for homogeneous random topologies, the phase transition belongs to the standard mean-field universality class, characterized by the order parameter exponent beta=1/2 . However, for scale-free networks we obtain phase transition exponents ranging from 1/2 to infinity. Furthermore, we show the existence of a phase transition even for values of the scale-free exponent in the interval (1.5,2], where the average network connectivity diverges.

Journal Article↗
PubMed2000

Structure of growing networks with preferential linking.

The model of growing networks with the preferential attachment of new links is generalized to include initial attractiveness of sites. We find the exact form of the stationary distribution of the number of incoming links of sites in the limit of long times, P(q), and the long-time limit of the average connectivity q(s,t) of a site s at time t (one site is added per unit of time). At long times, P(q) approximately q(-gamma) at q-->infinity and q(s,t) approximately (s/t)(-beta) at s/t-->0, where the exponent gamma varies from 2 to infinity depending on the initial attractiveness of sites. We show that the relation beta(gamma-1) = 1 between the exponents is universal.

Algorithms↗
PubMed2002

Truncation of power law behavior in "scale-free" network models due to information filtering.

We formulate a general model for the growth of scale-free networks under filtering information conditions-that is, when the nodes can process information about only a subset of the existing nodes in the network. We find that the distribution of the number of incoming links to a node follows a universal scaling form, i.e., that it decays as a power law with an exponential truncation controlled not only by the system size but also by a feature not previously considered, the subset of the network "accessible" to the node. We test our model with empirical data for the World Wide Web and find agreement.

Electronic Data Processing↗
PubMed2002

Consumer demand for caesarean sections in Brazil: informed decision making, patient choice, or social inequality? A population based birth cohort study linking ethnographic and epidemiological methods.

OBJECTIVES: To investigate why some women prefer caesarean sections and how decisions to medicalise birthing are influenced by patients, doctors, and the sociomedical environment. DESIGN: Population based birth cohort study, using ethnographic and epidemiological methods. SETTING: Epidemiological study: women living in the urban area of Pelotas, Brazil who gave birth in hospital during the study. Ethnographic study: subsample of 80 women selected at random from the birth cohort. Nineteen medical staff were interviewed. PARTICIPANTS: 5304 women who gave birth in any of the city's hospitals in 1993. MAIN OUTCOME MEASURES: Birth by caesarean section or vaginal delivery. RESULTS: In both samples women from families with higher incomes and higher levels of education had caesarean sections more often than other women. Many lower to middle class women sought caesarean sections to avoid what they considered poor quality care and medical neglect, resulting from social prejudice. These women used medicalised prenatal and birthing health care to increase their chance of acquiring a caesarean section, particularly if they had social power in the home. Both social power and women's behaviour towards seeking medicalised health care remained significantly associated with type of birth after controlling for family income and maternal education. CONCLUSIONS: Fear of substandard care is behind many poor women's preferences for a caesarean section. Variables pertaining to women's role in the process of redefining and negotiating medical risks were much stronger correlates of caesarean section rates than income or education. The unequal distribution of medical technology has altered concepts of good and normal birthing. Arguments supporting interventionist birthing for all on the basis of equal access to health care must be reviewed.

Adult↗
PubMed2006

Youth smoking prevention and tobacco industry revenue.

OBJECTIVES: Epidemiological surveys make it clear that youth smoking contributes to both current and future tobacco industry revenue: over 80% of adult smokers reportedly began smoking before age 18. This paper estimates annual and lifetime revenue from youth smoking, and highlights the association between declines in youth smoking and declines in tobacco industry revenue. MAIN OUTCOME MEASURES: This paper reports the amount of tobacco industry revenue generated by youth smoking at two points in time (1997 and 2002), and describes the distribution of youth generated tobacco income among the major tobacco companies. The authors project the amount of tobacco industry revenue that will be generated by members of two cohorts (the high school senior classes of 1997 and 2002) over the course of their lifetimes. RESULTS: In 1997, youth consumed 890 million cigarette packs, generating $737 million in annual industry revenue. By 2002, consumption dropped to 541 million packs and revenue increased to nearly $1.2 billion. Fifty eight per cent of youth generated revenue goes to Philip Morris USA, 18% to Lorillard, and 12% to RJ Reynolds. The authors project that, over the course of their lives, the 1997 high school senior class will smoke 12.4 billion packs of cigarettes, generating $27.3 billion in revenue. The 2002 high school senior class is projected to smoke 10.4 billion packs, generating $22.9 billion in revenue over the course of their lives. CONCLUSIONS: Cigarette price increases from 1997 to 2002 have resulted in greater revenue for the tobacco industry, despite declines in youth smoking prevalence. However, in the absence of further cigarette price increases, declines in youth smoking are projected to lead ultimately to a loss of approximately $4 billion in future tobacco industry revenue from a single high school cohort.

Adolescent↗
PubMed2000

Synaptic efficacy and the transmission of complex firing patterns between neurons.

In central neurons, the summation of inputs from presynaptic cells combined with the unreliability of synaptic transmission produces incessant variations of the membrane potential termed synaptic noise (SN). These fluctuations, which depend on both the unpredictable timing of afferent activities and quantal variations of postsynaptic potentials, have defied conventional analysis. We show here that, when applied to SN recorded from the Mauthner (M) cell of teleosts, a simple method of nonlinear analysis reveals previously undetected features of this signal including hidden periodic components. The phase relationship between these components is compatible with the notion that the temporal organization of events comprising this noise is deterministic rather than random and that it is generated by presynaptic interneurons behaving as coupled periodic oscillators. Furthermore a model of the presynaptic network shows how SN is shaped both by activities in incoming inputs and by the distribution of their synaptic weights expressed as mean quantal contents of the activated synapses. In confirmation we found experimentally that long-term tetanic potentiation (LTP), which selectively increases some of these synaptic weights, permits oscillating temporal patterns to be transmitted more effectively to the postsynaptic cell. Thus the probabilistic nature of transmitter release, which governs the strength of synapses, may be critical for the transfer of complex timing information within neuronal assemblies.

Animals↗
PubMed1983

Health care in Canada: patterns of funding and regulation.

During the 1970s the share of health care expenditure in Canadian GNP remained roughly stable, in the range of 7-71/2 percent of GNP, in marked contrast to its escalation in most other countries (the U.S. in particular) and to previous Canadian experience. The shift to a stable pattern coincided with the completion of the Canadian system of universal comprehensive public hospital and medical care insurance. This paper explores how and why the public insurance system served to contain cost escalation. It then discusses the inadequacy of expenditure experience per se as a basis for health system evaluation--the same data will support claims of both "underfunding" and "spiralling costs." More serious questions involve the influence of alternative patterns of health care funding and delivery on the effectiveness and efficiency of care provision, and the resulting distributional patterns of care and income. A brief sketch is given of the present situation and future possibilities of Canadian health care under these heads.

Canada↗
PubMed1987

Stress, ethnic and distribution factors in a dichotomous response model of alcohol abuse.

An emerging methodology, the dichotomous response model, is applied to alcohol abuse. The model permits the systematic integration of events and factors from various theories of alcohol abuse as well as random influences to affect the outcome. Both the sociological and distribution of consumption hypotheses are drawn on to specify the factors influencing alcohol abuse. The empirical results based on data from Canada and the United States indicate that ethnic and stress factors strongly influence alcohol abuse. The stress variables include the rates of unemployment and divorce. The ethnic variables are the percentages of the population that are of African, French, Italian and Mexican ancestry. Distribution variables such as price, income and control measures were generally less important.

Alcoholism↗
PubMed2003

Socioeconomic position and health in a population of Brazilian elderly: the Bambuí Health and Aging Study (BHAS).

OBJECTIVE: Despite the vast scientific literature on the social determinants of health, there is still a debate on the extent to which this relationship remains in old age. The objective of this study was to examine the association between socioeconomic circumstances and health among older adults in a small town in Brazil. METHODS: The study was carried out in Bambuí, a town of around 15 000 inhabitants that is located in the state of Minas Gerais, which is in southeastern Brazil. From 1 177 residents aged 65 years or older, 1 074 of them (91.2%) were interviewed and 997 (84.7%) were examined (physical measurements and blood tests). Those in the lowest third of the distribution of total household monthly income, with an income of less than US$ 240 per month, were compared with those who had an income above that level. RESULTS: Lower family income was independently associated with: (1) some lifestyle risk factors (less consumption of fresh fruits or vegetables and less frequent exercise during leisure time in the preceding 30 days), (2) several indicators of worse health status (General Health Questionnaire score, self-rated health, self-rated visual acuity, level of difficulty in walking 300 meters, inability to perform routine activities because of a health problem in the preceding 2 weeks, and seropositivity for Trypanosoma cruzi), (3) a higher number of nonprescribed medications used in the preceding 3 months, and (4) a higher number of hospitalizations in the preceding 12 months. Obesity was more frequent in the higher-income group. CONCLUSIONS: The results of this study do not confirm observations in some developed countries of a lack of association between socioeconomic status and health among the aged. Our results showed that a small difference in monthly family income was sufficiently sensitive to identify elderly persons in worse health, even within a community that appears to be uniformly poor.

Aged↗
PubMed2002

Factors of insulin resistance syndrome--related phenotypes are linked to genetic locations on chromosomes 6 and 7 in nondiabetic mexican-americans.

Insulin resistance syndrome (IRS)-related phenotypes, such as hyperinsulinemia, obesity-related traits, impaired glucose tolerance, dyslipidemia, and hypertension, tend to cluster into factors. We attempted to identify loci influencing the factors of IRS-related phenotypes using phenotypic data from 261 nondiabetic subjects distributed across 27 low-income Mexican-American extended families. Principal component factor analyses were performed using eight IRS-related phenotypes: fasting glucose (FG), fasting specific insulin (FSI), BMI, systolic blood pressure (SBP), diastolic blood pressure (DBP), HDL cholesterol, ln triglycerides (ln TGs), and leptin (LEP). The factor analysis yielded three factors: factor 1 (BMI, LEP, and FSI), factor 2 (DBP and SBP), and factor 3 (HDL and ln TG). We conducted multipoint variance components linkage analyses on these factors with the program SOLAR using a 10--15 cM map. We found significant evidence for linkage of factor 1 to two regions on chromosome 6 near markers D6S403 (logarithm of odds [LOD] = 4.2) and D6S264 (LOD = 4.9). We also found strong evidence for linkage of factor 3 to a genetic location on chromosome 7 between markers D7S479 and D7S471 (LOD = 3.2). In conclusion, we found substantial evidence for susceptibility loci on chromosomes 6 and 7 that appear to influence the factors representing the IRS-related phenotypes in Mexican-Americans.

Adult↗