927 resultados para Classificació AMS::01 History and biography
Resumo:
Extended gcd calculation has a long history and plays an important role in computational number theory and linear algebra. Recent results have shown that finding optimal multipliers in extended gcd calculations is difficult. We present an algorithm which uses lattice basis reduction to produce small integer multipliers x(1), ..., x(m) for the equation s = gcd (s(1), ..., s(m)) = x(1)s(1) + ... + x(m)s(m), where s1, ... , s(m) are given integers. The method generalises to produce small unimodular transformation matrices for computing the Hermite normal form of an integer matrix.
Resumo:
Background: The purpose of the present paper was to estimate the absolute risk of breast cancer over the remainder of a lifetime in Australian women with different categories of family history. Methods: Age-specific breast cancer incidence rates were adjusted for screening effects, and rates in those with no family history were estimated using the attributable fraction (AF). Relative risks from a published meta-analysis were applied to obtain incidence rates for different categories of family history, and age-specific incidence was converted to cumulative risk of breast cancer. The risk estimates were based upon Australian population statistics and published relative risks. Breast cancer incidence was from New South Wales women for 1996. The AF was calculated using prevalence of a family history of breast cancer from data on Queensland women. The cumulative absolute risk of breast cancer was calculated from decade and mid-decade ages to age 79 years, not adjusted for competing causes of death. Results: Lifetime risk is approximately 8.6% (1 in 12) for the general population and 7.8% (1 in 13) for those without a family history. Women with one relative affected have lifetime risks of 1 in 6-8 and those with two relatives affected have lifetime risks of 1 in 4-6. The cumulative residual lifetime risk decreases with advancing age; by age 60 years all groups with only one relative affected have well above a 90% probability of not developing breast cancer to age 79 years. Conclusions: These Australian risk statistics are useful for public information and in the clinical setting. Risks given here apply to women with average breast cancer risk from other risk factors.
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Background and Purpose-Subarachnoid hemorrhage (SAH) is more common in women than in men, but the role of hormonal factors in its etiology remains uncertain. The aim of this study was to examine the relationship between hormonal factors and risk of SAH in women. Methods-This was a prospective, multicenter, population-based, case-control study performed in 4 major urban centers in Australia and New Zealand. Two hundred sixty-eight female cases of first-ever aneurysmal SAH occurred during 1995-1998. Controls were 286 frequency-matched women from the general population of each center. Outcome measures included risk of SAH associated with use of oral contraceptive pills (OCPs), hormone replacement therapy (HRT), and various endogenous hormonal factors including menstrual patterns, parity, age at birth of first child, and breast-feeding practices. Results-Cases and controls did not differ with regard to menstrual and reproductive history except in age at bir th of first child, where older age was associated with reduced risk of SAH (odds ratio [OR], 0.63; 95% CI, 0.43, 0.91). Relative to never use of HRT, the adjusted OR for over use of HRT was 0.64 (95% CI, 0.41, 0.98), which did not alter significantly after further adjustment for possible confounding factors. Borderline evidence of an inverse association was detected for past use of HRT (adjusted OR, 0.59; 95% CI, 0.30, 1.13) and current use of HRT (adjusted OR, 0.67; 95% CI, 0.40, 1.13), but there was no evidence of an association for use of OCPs (adjusted OR, 0.97; 95% CI, 0.58, 1.60). Conclusions-The risks of SAH are lower in women whose first pregnancy is at an older age and women who have ever used HRT but not OCPs. The findings suggest an independent etiologic role for hormonal factors in the pathogenesis of aneurysmal SAH and provide support for a protective role fur HRT on risk of SAH in postmenopausal women.
Resumo:
A history of childhood trauma and the presence of dissociative phenomena are considered to be the most important risk factors for psychogenic nonepileptic seizure disorder (PNESD). This case-control study investigated 20 patients with PNESD and 20 with temporal lobe epilepsy (TLE) diagnosed by video/EEG monitoring who were matched for gender and age. Patients with both conditions were not included in the study. Groups were evaluated for age at onset and at diagnosis, worst lifetime weekly seizure frequency, trauma history, and presence of dissociative phenomena. Age at onset (P = 0.007) and age at diagnosis (P < 0.001) were significantly higher in the PNESD group than the control group, as were the scores on the Dissociative Experiences Scale (P < 0.001) and Childhood Trauma Questionnaire (P = 0.014). Only the differences in scores on the Childhood Trauma Questionnaire subscales Emotional Neglect (P = 0.013) and Emotional Abuse (P = 0.014) reached statistical significance. Dissociative phenomena and a reported history of childhood trauma are more common in patients with PNESD than in those with TLE. However, only emotional neglect and abuse were associated with PNESD in this study. (C) 2010 Elsevier Inc. All rights reserved.
Resumo:
Objective - To compare patterns of deaths from cirrhosis in Poland and Hungary in the context of differing alcohol policies in the 1980s. Design - Cohort analysis of deaths from chronic Liver disease and cirrhosis between 1959 and 1992 using mortality data from the World Health Organization database. Results - The pattern of alcohol related mortality in these countries is quite different. In both countries, death rates increased in the 1960s and 1970s. In Poland, this increase was arrested in 1980 and death rates have levelled out, with the exception of those in young females. In Hungary, rates have continued to climb, although the rate of increase decreased in the 1980s. This change coincides with the introduction of a policy, following the introduction of martial law, to reduce alcohol consumption. Conclusions - The countries of central and eastern Europe display many similarities in both political history and measures of health such as overall life expectancy. When examined more closely, substantial differences emerge. Policy makers must be cautious about adopting global solutions to health challenges that fail to take into account national variations.
Resumo:
The study of natural law theories is presently one of the most fruitful areas of research in the studies of early modern intellectual history, and moral and political theory. Likewise the historical significance of the Enlightenment for the development of modernisation' in many different forms continues to be the subject of controversy. This collection therefore offers a timely opportunity to re-examine both the coherence of the concept of an early Enlightenment', and the specific contribution of natural law theories to its formation. The works of major thinkers such as Grotius, Hobbes, Locke, Malebranche, Pufendorf and Thomasius are reassessed, and the appeal and importance of the discourse of natural jurisprudence both to those working inside conventional educational and political structures and to those outside - such as in the Huguenot diaspora - is evaluated. This volume will therefore be of importance to all those readers concerned to study the character of the debates in the period 1650-1750 surrounding moral and political agency, sovereignty and obligation, and the legitimation of religious toleration in the divergent states and patriotic contexts of Europe.
Resumo:
Selected as part of an anthology featuring best or most representative of 20th century art writing. Other authors in anthology included Benjamin, Greenberg, Krauss, T.j. Clark, Roger Fry, Stuart Hall, etc. Intended as US textbook. My essay featured as part of study day on globalism in art at Tate Modern. Essay itself subject of PhD thesis by Sally Butler of EMSAH and other subsequent commentaries.