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We propose a computational method for relativistic spin-1/2 particles by solving the corresponding Feshbach–Villars equation. We have found that the Feshbach–Villars spin-1/2 Hamiltonian can be written as two spin-coupled Feshbach–Villars spin-0 Hamiltonians. For the solution method, we adopted an integral equation formalism. The potential operators are represented in a discrete Hilbert space basis and the relevant Green’s operator has been calculated by a matrix continued fraction.

A computational method is proposed to calculate bound and resonant states by solving the Klein–Gordon and Dirac equations for real and complex energies, respectively. The method is an extension of a non-relativistic one, where the potential is represented in a Coulomb–Sturmian basis. This basis facilitates the exact analytic evaluation of the Coulomb Green’s operator in terms of a continued fraction. In the extension to relativistic problems, we cast the Klein–Gordon and Dirac equations into an effective Schrödinger form. Then the solution method is basically an analytic continuation of non-relativistic quantities like the angular momentum, charge, energy and potential into the effective relativistic counterparts.

Much recent archaeological research focuses on social forces as the impetus for cultural change. Soils, Climate and Society, however, focuses on the complex relationship between human populations and the physical environment, particularly the land--the foundation of agricultural production and, by extension, of agricultural peoples. The volume traces the origins of agriculture, the transition to agrarian societies, the sociocultural implications of agriculture, agriculture's effects on population, and the theory of carrying capacity, considering the relation of agriculture to the profound social changes that it wrought in the New World. Soil science plays a significant, though varied, role in each case study, and is the common component of each analysis. Soil chemistry is also of particular importance to several of the studies, as it determines the amount of food that can be produced in a particular soil and the effects of occupation or cultivation on that soil, thus having consequences for future cultivators. Soils, Climate and Society demonstrates that renewed investigation of agricultural production and demography can answer questions about the past, as well as stimulate further research. It will be of interest to scholars of archaeology, historical ecology and geography, and agricultural history.

Birth weight, adult weight, and girth as predictors of the metabolic syndrome in postmenopausal women: the Rancho Bernardo Study. D E Yarbrough , E Barrett-Connor , D Kritz-Silverstein and D L Wingard Department of Family and Preventive Medicine, University of California, San Diego, La Jolla 92093-0607, USA. Abstract OBJECTIVE: Recent studies have demonstrated an association between low birth weight and chronic and metabolic disorders in adulthood such as type 2 diabetes, hypertension, and dyslipidemia. These disorders tend to cluster in a condition known as the metabolic syndrome (syndrome X). Only two studies have reported an association of birth weight to the metabolic syndrome. The present study is distinguished as the only study to focus on postmenopausal women. RESEARCH DESIGN AND METHODS: Subjects were 303 community-dwelling, postmenopausal Caucasian women aged 50-84 years. Metabolic and anthropometric variables were measured at a clinic visit; birth weight was assessed by self-report on a mailed questionnaire. RESULTS: The metabolic syndrome, defined as the simultaneous presence of hypertension, dyslipidemia, and abnormal glucose tolerance, was present in 7.9% of these women. Compared with women in the highest birth weight tertile (8.1-13.0 lb, mean 9.4 lb), those in the lowest birth weight tertile (2.5-6.8 lb, mean 5.5 lb) exhibited an increased prevalence (12.0 vs. 4.3%, P < 0.05) and 2.41 times the risk (95% CI 1.06-5.51) of developing the metabolic syndrome. Women with a heavy birth weight had an increased risk of adult obesity. Nevertheless, women in the lowest birth weight tertile who became adults in the highest tertile of BMI (>25.2 kg/m2) or waist circumference (>80.7 cm) had the highest prevalence of the metabolic syndrome (approximately 30%). CONCLUSIONS: Low birth weight coupled with adult obesity is a strong determinant of the metabolic syndrome in postmenopausal women.

Objective. This study examines the sex-specific associations of plasma concentrations of iron, copper, and zinc with cognitive function in older community-dwelling adults.Design: Cross-sectional study.Setting: 1988–92 follow-up clinic visit.Participants: 602 men and 849 women (average age=75 ±8 years) who were community-dwelling and not clinically demented.Measurements: Blood samples were assayed for trace elements and 12 cognitive function tests were administered. Sex-specific analyses were adjusted for age, education, alcohol consumption, smoking, exercise, and estrogen use in women.Results. Men and women differed significantly in education and alcohol intake (p's<0.001), concentrations of plasma iron, copper and zinc (p's<0.001) and scores on 11 of 12 cognitive function tests (p=0.04 to <0.001). Regression analyses showed significant inverted U-shaped associations in men;both low and high iron levels were associated with poor performance on total and long-term recall and Serial 7's (p's=0.018, 0.042 and 0.004, respectively) compared to intermediate concentrations. In women, iron and copper concentrations had inverse linear associations with Buschke total, long and short-term recall and Blessed scores (p's<0.05). Zinc was positively associated with performance on Blessed Items (p=0.008). Analyses comparing cognitive function using categorically defined mineral concentrations yielded similar sex specific results.Conclusion. Optimal trace element concentrations may exist for optimal cognitive function in older adults, and these levels may differ by sex and cognitive function domain.

To compare the prevalence of type 2 diabetes and features of the metabolic syndrome among Filipina and Caucasian women in San Diego County, California. Data on several chronic diseases were collected between 1992 and 1999 from community-dwelling Filipina (n=294) and Caucasian (n=379) women aged 50-69 years. Filipina and Caucasian women did not differ in mean age (59.7 vs. 60 years, respectively), BMI (25.6 vs. 25.4 kg/m(2)), percentage of body fat (33.5 vs. 34.2%), or waist-to-hip ratio (0.84 vs. 0.83), although Filipinas had larger waist circumferences and higher percentages of truncal fat. Compared with Caucasians, Filipinas were less likely to be obese (BMI > or = 30 kg/m(2), 8.8 vs. 14%, P=0.04) and less likely to smoke, consume alcohol, or take postmenopausal estrogen; Filipinas also had lower levels of HDL cholesterol. Compared with Caucasians, Filipinas had higher prevalence of type 2 diabetes by oral glucose tolerance test criteria (36 vs. 9%) and the metabolic syndrome (34 vs. 13%). These differences persisted after adjusting for age, body size, fat distribution, percentage of body fat, smoking, alcohol consumption, exercise, and estrogen therapy. A total of 10% of Filipinas with diabetes were obese, compared with one third of Caucasians with diabetes. The finding of a high prevalence of diabetes in an unstudied nonobese ethnic group reinforces the importance of expanding the study of diabetes to diverse populations. The high prevalence of diabetes in populations who are not of Northern European ancestry may be missed when they are not obese by Western standards.

In several clinical trials of interventions designed to lower plasma cholesterol, reductions in coronary heart disease mortality have been offset by an unexplained rise in suicides and other violent deaths. We have tried to find out whether depressive illness is related to low plasma cholesterol concentrations in men of 50 years and older. In 1985-87, Beck depression inventories were obtained from 1020 white men, aged 50-89 years, in the Rancho Bernardo, California, cohort. Disease history and behaviours were assessed by standard questionnaires. Plasma cholesterol and weight were measured at this time, as they had been in 1972-74. Among men aged 70 years and older, categorically defined depression was three times more common in the group with low plasma cholesterol (<4·14 mmol/L) than in those with higher concentrations (5/31 [16%] vs 22/363 [6%]; p=0·033). Depressive symptom scores correlated significantly and inversely with plasma cholesterol concentrations, even after adjustment for age, health status, number of chronic illnesses, number of medications, and exercise, as well as measured weight loss and change in plasma cholesterol in the previous 13 years. Our finding that low plasma cholesterol is associated with depressive symptoms in elderly men is compatible with observations that a very low total cholesterol may be related to suicide and violent death. Since cholesterol lowering in the general population is widely recommended, this observation warrants further investigation.

To evaluate the association of thyroid stimulating hormone levels with cognitive function and depressed mood in a community-based sample. Cross-sectional study. Clinic visit in 1999–2003. Community-dwelling men (N=447) and women (N=663) aged 42–99 years. Cognitive function was assessed with the Buschke-Fuld Selective Reminding Test, the Modified Mini-Mental State Examination, Trails B, and category fluency. Depressed mood was assessed with the Beck Depression Inventory (BDI). A fasting blood sample was obtained for thyroid stimulating hormone (TSH) measurement. Mean age was 73.6±10.0 in men and 74.3±10.4 in women. Mean TSH was 1.9 μIU/ml in both sexes; 9.0% of men and 24% of women reported thyroid medication use. Mean BDI scores were 4.6±4.1 in men and 5.2±4.3 in women; 9% of men and 11% of women used antidepressants. Before and after adjustment for covariates or exclusion of participants taking thyroid hormones, no associations were observed between TSH and cognitive function (ps>0.10). TSH was inversely associated with BDI (p=0.03) in men, but not women. Thyroid stimulating hormone level was unrelated to cognitive function in men and women, and was inversely associated with depressed mood in men only, possibly reflecting the greater use of both thyroid medications and antidepressants by women.

Uncertainties persist about the magnitude of associations of diabetes mellitus and fasting glucose concentration with risk of coronary heart disease and major stroke subtypes. We aimed to quantify these associations for a wide range of circumstances. We undertook a meta-analysis of individual records of diabetes, fasting blood glucose concentration, and other risk factors in people without initial vascular disease from studies in the Emerging Risk Factors Collaboration. We combined within-study regressions that were adjusted for age, sex, smoking, systolic blood pressure, and body-mass index to calculate hazard ratios (HRs) for vascular disease. Analyses included data for 698 782 people (52 765 non-fatal or fatal vascular outcomes; 8·49 million person-years at risk) from 102 prospective studies. Adjusted HRs with diabetes were: 2·00 (95% CI 1·83–2·19) for coronary heart disease; 2·27 (1·95–2·65) for ischaemic stroke; 1·56 (1·19–2·05) for haemorrhagic stroke; 1·84 (1·59–2·13) for unclassified stroke; and 1·73 (1·51–1·98) for the aggregate of other vascular deaths. HRs did not change appreciably after further adjustment for lipid, inflammatory, or renal markers. HRs for coronary heart disease were higher in women than in men, at 40–59 years than at 70 years and older, and with fatal than with non-fatal disease. At an adult population-wide prevalence of 10%, diabetes was estimated to account for 11% (10–12%) of vascular deaths. Fasting blood glucose concentration was non-linearly related to vascular risk, with no significant associations between 3·90 mmol/L and 5·59 mmol/L. Compared with fasting blood glucose concentrations of 3·90–5·59 mmol/L, HRs for coronary heart disease were: 1·07 (0·97–1·18) for lower than 3·90 mmol/L; 1·11 (1·04–1·18) for 5·60–6·09 mmol/L; and 1·17 (1·08–1·26) for 6·10–6·99 mmol/L. In people without a history of diabetes, information about fasting blood glucose concentration or impaired fasting glucose status did not significantly improve metrics of vascular disease prediction when added to information about several conventional risk factors. Diabetes confers about a two-fold excess risk for a wide range of vascular diseases, independently from other conventional risk factors. In people without diabetes, fasting blood glucose concentration is modestly and non-linearly associated with risk of vascular disease. British Heart Foundation, UK Medical Research Council, and Pfizer.