959 resultados para Montgomery, John K.
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Also issued under Spanish and Portuguese titles.
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Mode of access: Internet.
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Mode of access: Internet.
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Includes bibliography.
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Based on the epidemiological finding that individuals with schizophrenia tend to be born in winter/spring when compared to the general population, we examined (1) the strength and timing of this effect in Northern Hemisphere sites, and (2) the correlation between the season of birth effect size and latitude. Studies were located via electronic data sources, published citations, and letters to authors. Inclusion criteria were that studies specify the diagnostic criteria used, that studies specify the counts of schizophrenia and general population births for each month, and that subjects and the general population be drawn from the same birth years and catchment area. We extracted data from eight studies based on 126,196 patients with schizophrenia and 86,605,807 general population births and drawn from 27 Northern Hemisphere sites. Comparing winter/spring versus summer/autumn births, we found a significant excess for winter/spring births (pooled odds ratio = 1.07; 95% confidence interval 1.05, 1.08; population attributable risk = 3.3%). There was a small but significant positive correlation between the odds ratios for the season of birth comparison and latitude (r = 0.271, p < 0.005). Furthermore, the shape of the seasonality in schizophrenia births varied by latitude band. These variations may encourage researchers to generate candidate seasonally fluctuating exposures.
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First, this study examined genetic and environmental sources of variation in performance on a standardised test of academic achievement, the Queensland Core Skills Test (QCST) (Queensland Studies Authority, 2003a). Second, it assessed the genetic correlation among the QCST score and Verbal and Performance IQ measures using the Multidimensional Aptitude Battery (MAB), [Jackson, D. N. (1984) Multidimensional Aptitude Battery manual. Port Huron, MI:Research Psychologist Press, Inc.]. Participants were 256 monozygotic twin pairs and 326 dizygotic twin pairs aged from 15 to 18 years (mean 17 years +/- 0.4 [SD]) when achievement tested, and from 15 to 22 years (mean 16 years +/- 0.4 [SD]) when IQ tested. Univariate analysis indicated a heritability for the QCST of 0.72. Adjustment to this estimate due to truncate selection (downward adjustment) and positive phenotypic assortative mating (upward adjustment) suggested a heritability of 0.76 The phenotypic (0.81) and genetic (0.91) correlations between the QCST and Verbal IQ (VIQ) were significantly stronger than the phenotypic (0.57) and genetic (0.64) correlations between the QCST and Performance IQ (PIQ). The findings suggest that individual variation in QCST performance is largely due to genetic factors and that common environmental effects may be substantially accounted for by phenotypic assortative mating. Covariance between academic achievement on the QCST and psychometric IQ (particularly VIQ) is to a large extent due to common genetic influences.
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Phytochemicals have provided an abundant and effective source of therapeutics for the treatment of cancer. Here we describe the characterization of a novel plant toxin, persin, with in vivo activity in the mammary gland and a p53-, estrogen receptor-, and Bcl-2-independent mode of action. Persin was previously identified from avocado leaves as the toxic principle responsible for mammary gland-specific necrosis and apoptosis in lactating livestock. Here we used a lactating mouse model to confirm that persin has a similar cytotoxicity for the lactating mammary epithelium. Further in vitro studies in a panel of human breast cancer cell lines show that persin selectively induces a G(2)-M cell cycle arrest and caspase-dependent apoptosis in sensitive cells. The latter is dependent on expression of the BH3-only protein Bim. Bim is a sensor of cytoskeletal integrity, and there is evidence that unique structure of the compound, persin could represent a novel class of microtubule-targeting agent with potential specificity for breast cancers.
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Leptospirosis is one of the most common zoonotic diseases in the world, resulting in high morbidity and mortality in humans and affecting global livestock production. Most infections are caused by either Leptospira borgpetersenii or Leptospira interrogans, bacteria that vary in their distribution in nature and rely on different modes of transmission. We report the complete genomic sequences of two strains of L. borgpetersenii serovar Hardjo that have distinct phenotypes and virulence. These two strains have nearly identical genetic content, with subtle frameshift and point mutations being a common form of genetic variation. Starkly limited regions of synteny are shared between the large chromosomes of L. borgpetersenii and L. interrogans, probably the result of frequent recombination events between insertion sequences. The L. borgpetersenii genome is ≈700 kb smaller and has a lower coding density than L. interrogans, indicating it is decaying through a process of insertion sequence-mediated genome reduction. Loss of gene function is not random but is centered on impairment of environmental sensing and metabolite transport and utilization. These features distinguish L. borgpetersenii from L. interrogans, a species with minimal genetic decay and that survives extended passage in aquatic environments encountering a mammalian host. We conclude that L. borgpetersenii is evolving toward dependence on a strict host-to-host transmission cycle.
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The importance of technology to developing countries is widely recognised as they compete internationally and develop internally. Firms acquire technology by different means and from diverse sources, and they possess varying levels of competence. Since countries are at various stages of economic and technological development, prescriptive approaches to technology and operations integration are not appropriate. The paper discusses factors in the literature that affect the integration of technology and operations in developing countries. Country similarities and differences also play a role, so the study examines three developing countries: Brazil, India and South Africa. These countries are emerging from periods of regulation and have developed certain sectors of their economies. Empirical evidence is provided from a study of managers in South Africa who were asked to assess the important factors in technology integration, and to score the extent to which they can control these. Results from the study concur with the literature regarding the importance of a country’s political stability and its policies towards new investment and infrastructure. Knowledge and understanding of technology are essential for successful integration in countries with insufficient skilled personnel, and where education levels are low.
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The further development of the use of NMR relaxation times in chemical, biological and medical research has perhaps been curtailed by the length of time these measurements often take. The DESPOT (Driven Equilibrium Single Pulse Observation of T1) method has been developed, which reduces the time required to make a T1 measurement by a factor of up to 100. The technique has been studied extensively herein and the thesis contains recommendations for its successful experimental application. Modified DESPOT type equations for use when T2 relaxation is incomplete or where off-resonance effects are thought to be significant are also presented. A recently reported application of the DESPOT technique to MR imaging gave good initial results but suffered from the fact that the images were derived from spin systems that were not driven to equilibrium. An approach which allows equilibrium to be obtained with only one non-acquisition sequence is presented herein and should prove invaluable in variable contrast imaging. A DESPOT type approach has also been successfully applied to the measurement of T1. T_1's can be measured, using this approach significantly faster than by the use of the classical method. The new method also provides a value for T1 simultaneously and therefore the technique should prove valuable in intermediate energy barrier chemical exchange studies. The method also gives rise to the possibility of obtaining simultaneous T1 and T1 MR images. The DESPOT technique depends on rapid multipulsing at nutation angles, normally less than 90^o. Work in this area has highlighted the possible time saving for spectral acquisition over the classical technique (90^o-5T_1)_n. A new method based on these principles has been developed which permits the rapid multipulsing of samples to give T_1 and M_0 ratio information. The time needed, however, is only slightly longer than would be required to determine the M_0 ratio alone using the classical technique. In ^1H decoupled ^13C spectroscopy the method also gives nOe ratio information for the individual absorptions in the spectrum.
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Peer reviewed
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La articulación entre las políticas de empleo y las políticas sociales condicionan la percepción subjetiva de incertidumbre los individuos. El modelo de mercado laboral tiene un peso determinante en la percepción de incertidumbre. El empleo en sí mismo ya no es suficiente garantía de ingresos seguros. El empleo a tiempo parcial y los contratos temporales generan una creciente demanda de políticas de redistribución de los ingresos en los países del Sur y Este de Europa. En los países escandinavos los mismos tipos de contratos laborales generan menos desigualdad porque el empleo público contribuye a generar un “círculo virtuoso” que favorece las políticas de igualdad y la conciliación entre la vida laboral y familiar. A nivel individual las actitudes pro-redistributivas las impulsan las mujeres, aquellas personas con incertidumbre en sus ingresos económicos y con bajo nivel de estudios. Por el contrario, quienes más confían en el éxito individual y el mérito son los jóvenes con estudios universitarios y aquellos que perciben ingresos económicos altos.
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Background: Globally, there is a progressive rise in the burden of non-communicable diseases (NCDs). This paper examined the health and social concerns of parents/caregivers on in-patient care for children with NCDs in Ghana. Methods: This was a cross-sectional study in three large health facilities in Ghana (the largest in the South, the largest in the North and the largest in the Eastern part of Ghana. Data was collected with a structured questionnaire among 225 caregivers (≥18 years) of 149 children with NCDs in health facilities in the three regions. Data was analyzed with simple descriptive statistics. Results: Most caregivers 169(75.0%) were women, relatively young (median age 35years), mostly married and resided in urban areas. Sickle cell disease was the commonest NCD among the children. All 169(75.0%) caregivers believed children suffer NCDs because of sins of parents/ancestors, 29(12.9%) believed herbalists/spiritualists have insights into treating NCDs and 73(32.6%) have previously used herbs/traditional medicine for child's illness. NCD in children was a burden and caused financial difficulties for families. Most caregivers (>96.0%) indicated NCDs in children should be included in national health insurance benefits package and a comprehensive national NCD policy is needed. Conclusion: Absence of national NCD policy for children is a major challenge. The burden of care rests mainly on the parents/ caregivers. A national strategic intervention on the importance of awareness generation on the causes, risk factors, prevention and treatment of NCDs for families and communities is essential. Government support through national health and social policy initiatives are essential.
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No era Ernest Lluch individuo propenso a adoptar un singular libro de cabecera, ni a seguir con fidelidad las huellas de un único maestro. Pero, por supuesto, tenía su personal esquema devalores y sus escalas de preferencias. Y uno de los autores que sin discusión estaba presente en su galería privada de economistas ilustres fue Piero Sraffa (1898-1983). Creo que también habríacolocado en esa división de honor a François Quesnay, Adam Smith, David Ricardo, Karl Marx, Knut Wicksell, John M. Keynes, Joseph A.Schumpeter, Maurice H. Dobb, Wassily Leontief, John K. Galbraith, Paolo Sylos Labini y Albert O. Hirschman.
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1. Sawfishes currently are among the most threatened elasmobranchs in the world. Only two species inhabit Atlantic waters: the largetooth sawfish (Pristis pristis) and the smalltooth sawfish (Pristis pectinata), both having suffered dramatic declines in their ranges. 2. The goal of this study was to evaluate the status of P. pristis in the Atlantic, and estimate local extinction risk based on historical and recent occurrence records. In order to accomplish these goals, a thorough search for historical and recent records of P. pristis in the Atlantic was conducted, by reviewing scientific and popular literature, museum specimens, and contacting regional scientists from the species’ historical range. 3. In total, 801 P. pristis records (1830–2009) document its occurrence in four major regions in the Atlantic: USA (n =41), Mexico and Central America (n =535), South America (n=162), and West Africa (n =48). Locality data were not available for 15 records. 4. Historical abundance centres were the Colorado-San Juan River system in Nicaragua and Costa Rica (and secondarily Lake Izabal of Guatemala), the Amazon estuary, and coastal Guinea-Bissau. 5. Currently, the species faces drastic depletion throughout its entire former range and centres of abundance. It appears to have been extirpated from several areas. The probability of extinction was highest in the USA, northern South America (Colombia to Guyane), and southern West Africa (Cameroon to Namibia). 6. Currently, the Amazon estuary appears to have the highest remaining abundance of P. pristis in the Atlantic, followed by the Colorado–San Juan River system in Nicaragua and Costa Rica and the Bissagos Archipelago in Guinea Bissau. Therefore the protection of these populations is crucial for the preservation and recovery of the species.