48 research outputs found

    A Lie algebra attached to a projective variety

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    Each choice of a K\"ahler class on a compact complex manifold defines an action of the Lie algebra \slt on its total complex cohomology. If a nonempty set of such K\"ahler classes is given, then we prove that the corresponding \slt-copies generate a semisimple Lie algebra. We investigate the formal properties of the resulting representation and we work things out explicitly in the case of complex tori, hyperk\"ahler manifolds and flag varieties. We pay special attention to the cases where this leads to a Jordan algebra structure or a graded Frobenius algebra.Comment: AMSTeX v2.1, 46 page

    Quantifying the advantages and disadvantages of pre-placement genetic screening

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    BACKGROUND: Tests of genotype may enable workers at unusual risk of future ill-health to be identified. Using them to select for employment, however, entails gains and losses to employers and employees. Ensuring a fair balance between the rights and obligations of each group requires a value judgement, but the advantages and disadvantages to interested parties must first be quantified in a meaningful way. METHOD AND RESULTS: The purposes of pre-employment screening are reviewed, and several simple measures relevant to the separate interests of employers and job applicants proposed-number screened to prevent a single adverse outcome; number excluded to prevent a case; expected incidence of the adverse outcome in those excluded; and preventable fraction. The derivation of these measures is illustrated, and the factors that influence them (the prevalence of the prognostic trait, the relative risk that it carries for an adverse outcome, and the overall incidence of disease) are related algebraically and graphically, to aid judgement on the utility of screening under different circumstances. CONCLUSIONS: In sensitive areas such as genetic testing the onus should be on the employer to justify plans for pre-placement screening. Several quantitative measures can be used to inform the ethical and economic debate about screening and to evaluate alternative strategies for prevention

    Mortality of workers exposed to ethylene oxide: extended follow up of a British cohort

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    Aims: To obtain further information about the risks of cancer associated with occupational exposure to ethylene oxide Methods: Follow up was extended by 13 years for a cohort of 2876 men and women with definite or potential exposure to ethylene oxide in the chemical industry or in hospital sterilising units. Subjects were traced through National Health Service and social security records, and their mortality was compared with that expected from rates in the national population by the person-years method. Results: Analysis was based on 565 deaths, of which 339 had occurred during the additional period of follow up. Mortality was close to or below expectation for all causes (565 deaths v 607.6 expected), all cancers (188 v 184.2), and for all specific categories of malignancy including stomach cancer (10 v 11.6), breast cancer (11 v 13.2), non-Hodgkin’s lymphoma (7 v 4.8), and leukaemia (5 v 4.6). All five deaths from leukaemia occurred in the subset of subjects with greatest potential for exposure to ethylene oxide, but even in this group the excess of deaths was small (2.6 expected). Conclusions: The balance of evidence from this and other epidemiological investigations indicates that any risk of human cancer from ethylene oxide is low, particularly at the levels of occupational exposure that have occurred in Britain over recent decades. This may reflect the capacity of human cells to repair DNA damage caused by the chemical, which is a potent genotoxin and animal carcinogen

    Health-related job loss: findings from a community-based survey

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    AIMS: To explore the frequency, nature, determinants and outcome of health-related job loss (HRJL) in men sampled from the general population of three rural areas. METHODS: Data on lifetime occupational history, including any HRJL, were obtained as part of a postal survey of men aged 24-70 years in three rural areas of England and Wales. Incidence rates were calculated for first health-related loss of a job that had been held for >or=1 year. Associations with risk factors were examined by Poisson regression, and by application of conditional logistic regression in a nested case-control study. RESULTS: HRJL was reported by 1408 (13%) of the 10 559 men who had held long-term jobs. The incidence rose steeply with age for cardiorespiratory and neurological disorders, but for accidents and poisoning the trend was, if anything, in the reverse direction. An increase in incidence over time was most marked for musculoskeletal disorders and mental illness, and much less prominent for cardiorespiratory and neurological disease. In comparison with other occupations, the risk was lower in agricultural workers (odds ratio (OR) 0.6, 95% CI 0.5 to 0.8), and higher in policemen (OR 2.4, 95% CI 1.6 to 3.7) and teachers (OR 2.0, 95% CI 1.5 to 2.7), this differential being even greater for HRJL caused by mental illness. Risk was also increased in employees relative to the self-employed (OR 2.0, 95% CI 1.7 to 2.3). Shift work was associated with a higher incidence of job loss caused by mental illness (OR 1.5, 95%CI 1.1-2.2), and heavy lifting with HRJL caused by musculoskeletal disorders (OR 2.6, 95% CI 2.0 to 3.5). After HRJL, 61% of subjects had subsequently obtained further long-term employment, usually within 1 year. CONCLUSIONS: In the population studied, HRJL has become increasingly common, especially in relation to musculoskeletal disorders and mental illness. In addition to being associated with ergonomic stresses in the workplace, it may be importantly influenced by cultural and economic factors. Future research should focus on the minority of workers who leave a job for health reasons and do not rapidly return to further work

    Changing minds? Not in Congress!

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    This paper shows a variety of evidence that members of Congress are ideologically consistent. Based upon the roll call voting record, once elected to Congress, members adopt a consistent ideological position and maintain it over time. There may be changing minds, but they are not in Congress. Copyright Springer Science+Business Media, LLC 2007Congress, NOMINATE, Optimal Classification,

    Non-fatal occupational injuries in British agriculture

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    OBJECTIVES: To investigate the incidence, nature and determinants of non-fatal occupational injuries in British agriculture. METHODS: As part of a postal survey, data on lifetime histories of work in agriculture and occupational accidents were obtained from men born between 1933 and 1977 and residing in three rural areas of England and Wales. Incidence rates for different categories of accident were compared with those derived from statutory reporting. Associations with risk factors were explored by Poisson regression, and summarised by incidence rate ratios (IRRs). RESULTS: Of the 10 765 responders (response rate = 31%), 3238 (30%) reported at least one occupational accident at the ages of 14-64 years, leading to absence from work for >or=3 days, including 1492 accidents that could be linked to a specific job listed in the history of agricultural work. The reported incidence of injuries in agriculture was markedly higher than that derived from statutory reporting, particularly for self-employed farmers. During 1996-2003, the highest rates of agricultural accidents were from handling, lifting or carrying (4.9/1000 person-years), falls from a height (4.6/1000 person-years) and injury by animals (3.4/1000 person-years). After adjustment for calendar period and age, the risk of accidents was elevated in men who had only recently entered agricultural work (IRR 3.7, 95% CI 2.7 to 5.1 for men who had worked in agriculture for up to 1 year relative to those who had entered the industry >25 years earlier), and in those who carried out forestry (IRR 1.7, 95% CI 1.5 to 1.9). CONCLUSION: Our findings confirm the substantial underascertainment of serious accidental injuries in agriculture through statutory reporting, particularly for the self-employed. The risk of accidents is highest in new recruits to the industry and in those undertaking forestry, and these groups should be a target for further preventive action

    A prospective cohort study of arm pain in primary care and physiotherapy--prognostic determinants

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    OBJECTIVE: To investigate outcome and prognostic determinants for arm pain presenting to primary care and physiotherapy services. METHODS: Patients with arm pain were recruited as they presented to primary care and physiotherapy services, and were followed for 12 months. At baseline, they were classified by diagnosis using a validated examination schedule. Depression, somatizing tendency, health anxiety, fear-avoidance beliefs and chronic pain outside the arm were ascertained using standard definitions. Three outcomes were considered: same-site pain during the final month of follow-up (continuing pain); pain present on most days of that month; and pain present without a break of 7 days over follow-up ('unremitting' pain). Associations were explored in multi-level logistic regression models and summarized as odds ratios (ORs) with 95% confidence intervals (95% CIs). RESULTS: Altogether, 313 (83%) of 375 subjects completed follow-up, including 53% with 'continuing' and 24% with 'unremitting' pain. 'Continuing' pain was predicted most strongly by male sex (OR 1.9, 95% CI 1.2-3.2) (this association was restricted largely to the elbow), higher frequency of pain in the past month at baseline (OR 2.5, 95% CI 1.1-5.6), chronic pain at sites outside the arm (ORs 1.6-2.4 for different sites) and current smoking (OR 3.3, 95% CI 1.6-6.6). There were also indications that mental health and fear-avoidance beliefs influenced prognosis. Predictors for the other two adverse outcomes were similar. CONCLUSION: Arm pain often persists in patients who consult medical services. Predictors of persistence include male sex (elbow only), frequency of pain at baseline, chronic pain at other sites and smokin

    Exposure to metal fume and infectious pneumonia

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    To test the hypothesis that inhalation of metal fume reversibly increases susceptibility to pneumonia, the authors conducted a case-control study. Men aged 20–64 years, admitted to 11 hospitals in West Midlands, England, with community-acquired pneumonia during 1996–1999 were interviewed about their lifetime occupational history, exposure to metal fume, and potential confounding factors. Similar information was collected from controls admitted to the same hospitals with nonrespiratory illness. For cases, exposures were timed relative to the onset of their illness (on average, 6 months before interview). Exposure histories for controls were censored 6 months before interview. Interviews were completed by 525 cases and 1,122 controls (response rates of 74% and 99%). Pneumonia was associated with reported occupational exposure to metal fume in the previous year (adjusted odds ratio (OR) = 1.6, 95% confidence interval (CI): 1.1, 2.4) but not in earlier periods (OR = 1.1). The risk was highest for lobar pneumonia and recent exposure to ferrous fume (OR = 2.3, 95% CI: 1.2, 4.3). The association was not specific to any one microorganism. These findings support the hypothesis that ferrous and possibly other metal fumes reversibly predispose to infectious pneumonia. Research should now focus on the underlying mechanisms and prevention. <br/
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