Variance components analyses of multiple asthma traits in a large sample of Australian families ascertained through a twin proband

Background: Intermediate phenotypes are often measured as a proxy for asthma. It is largely unclear to what extent the same set of environmental or genetic factors regulate these traits. Objective: Estimate the environmental and genetic correlations between self-reported and clinical asthma traits. Methods: A total of 3073 subjects from 802 families were ascertained through a twin proband. Traits measured included self-reported asthma, airway histamine responsiveness (AHR), skin prick response to common allergens including house dust mite (Dermatophagoides pteronyssinus [D. pter]), baseline lung function, total serum immunoglobulin E (IgE) and eosinophilia. Bivariate and multivariate analyses of eight traits were performed with adjustment for ascertainment and significant covariates. Results: Overall 2716 participants completed an asthma questionnaire and 2087 were clinically tested, including 1289 self-reported asthmatics (92% previously diagnosed by a doctor). Asthma, AHR, markers of allergic sensitization and eosinophilia had significant environmental correlations with each other (range: 0.23-0.89). Baseline forced expiratory volume in 1 s (FEV1) showed low environmental correlations with most traits. Fewer genetic correlations were significantly different from zero. Phenotypes with greatest genetic similarity were asthma and atopy (0.46), IgE and eosinophilia (0.44), AHR and D. pter (0.43) and AHR and airway obstruction (-0.43). Traits with greatest genetic dissimilarity were FEV1 and atopy (0.05), airway obstruction and IgE (0.07) and FEV1 and D. pter (0.11). Conclusion: These results suggest that the same set of environmental factors regulates the variation of many asthma traits. In addition, although most traits are regulated to great extent by specific genetic factors, there is still some degree of genetic overlap that could be exploited by multivariate linkage approaches.

Assortative Mating for Cigarette Smoking and for Alcohol Consumption in Female Australian Twins and their Spouses

Background Non-random mating affects population variation for substance use and dependence. Developmentally, mate selection leading to positive spousal correlations for genetic similarity may result in increased risk for substance use and misuse in offspring. Mate selection varies by cohort and thus, assortative mating in one generation may produce marked changes in rates of substance use in the next. We aim to clarify the mechanisms contributing to spousal similarity for cigarette smoking and alcohol consumption. Methods Using data from female twins and their male spouses, we fit univariate and bivariate twin models to examine the contribution of primary assortative mating and reciprocal marital interaction to spousal resemblance for regular cigarette smoking and nicotine dependence, and for regular alcohol use and alcohol dependence. Results We found that assortative mating significantly influenced regular smoking, regular alcohol use, nicotine dependence and alcohol dependence. The bivariate models for cigarette smoking and alcohol consumption also highlighted the importance of primary assortative mating on all stages of cigarette smoking and alcohol consumption, with additional evidence for assortative mating across the two stages of alcohol consumption. Conclusions Women who regularly used, and subsequently were dependent on cigarettes or alcohol were more likely to marry men with similar behaviors. After mate selection had occurred, one partner's cigarette or alcohol involvement did not significantly modify the other partner's involvement with these psychoactive substances.

A side order of stem cells: The SP phenotype

A defining property of murine hematopoietic stein cells (HSCs) is low fluorescence after staining with Hoechst 33342 and Rhodamine 123. These dyes have proven to be remarkably powerful tools in the purification and characterization of HSCs when used alone or in combination with antibodies directed against stem cell epitopes. Hoechst low cells are described as side population (SP) cells by virtue of their typical profiles in Hoechst red versus Hoechst blue bivariate fluorescent-activated cell sorting dot plots. Recently, excitement has been generated by the findings that putative stem cells from solid tissues may also possess this SP phenotype. SP cells have now been isolated from a wide variety of mammalian tissues based on this same dye efflux phenomenon, and in many cases this cell population has been shown to contain apparently multipotent stem cells. What is yet to be clearly addressed is whether cell fusion accounts for this perceived SP multipotency. Indeed, if low fluorescence after Hoechst staining is a phenotype shared by hematopoietic and organ-specific stem cells, do all resident tissue SP cells have bone marrow origins or might the SP phenotype be a property common to all stem cells? Subject to further analysis, the SP phenotype may prove invaluable for the initial isolation of resident tissue stem cells in the absence of definitive cell-surface markers and may have broad-ranging applications in stem cell biology, from the purification of novel stem cell populations to the development of autologous stem cell therapies.

A stochastic metapopulation model accounting for habitat dynamics

A stochastic metapopulation model accounting for habitat dynamics is presented. This is the stochastic SIS logistic model with the novel aspect that it incorporates varying carrying capacity. We present results of Kurtz and Barbour, that provide deterministic and diffusion approximations for a wide class of stochastic models, in a form that most easily allows their direct application to population models. These results are used to show that a suitably scaled version of the metapopulation model converges, uniformly in probability over finite time intervals, to a deterministic model previously studied in the ecological literature. Additionally, they allow us to establish a bivariate normal approximation to the quasi-stationary distribution of the process. This allows us to consider the effects of habitat dynamics on metapopulation modelling through a comparison with the stochastic SIS logistic model and provides an effective means for modelling metapopulations inhabiting dynamic landscapes.

Effects of rock properties on specific cutting energy in linear cutting of sandstones by picks

Specific cutting energy (SE) has been widely used to assess the rock cuttability for mechanical excavation purposes. Some prediction models were developed for SE through correlating rock properties with SE values. However, some of the textural and compositional rock parameters i.e. texture coefficient and feldspar, mafic, and felsic mineral contents were not considered. The present study is to investigate the effects of previously ignored rock parameters along with engineering rock properties on SE. Mineralogical and petrographic analyses, rock mechanics, and linear rock cutting tests were performed on sandstone samples taken from sites around Ankara, Turkey. Relationships between SE and rock properties were evaluated using bivariate correlation and linear regression analyses. The tests and subsequent analyses revealed that the texture coefficient and feldspar content of sandstones affected rock cuttability, evidenced by significant correlations between these parameters and SE at a 90% confidence level. Felsic and mafic mineral contents of sandstones did not exhibit any statistically significant correlation against SE. Cementation coefficient, effective porosity, and pore volume had good correlations against SE. Poisson's ratio, Brazilian tensile strength, Shore scleroscope hardness, Schmidt hammer hardness, dry density, and point load strength index showed very strong linear correlations against SE at confidence levels of 95% and above, all of which were also found suitable to be used in predicting SE individually, depending on the results of regression analysis, ANOVA, Student's t-tests, and R-2 values. Poisson's ratio exhibited the highest correlation with SE and seemed to be the most reliable SE prediction tool in sandstones.

Relationship between work performance and personality traits in Hong Kong organizational settings

Four hundred and thirty-seven employees from four Hong Kong organizations completed the Traditional Chinese versions of the Fifteen Factor Personality Questionnaire Plus (15FQ+) and the Cross-Cultural Personality Assessment Inventory (CPAI-2) (indigenous scales) and provided objective and memory-based recent performance appraisal scores. A number of significant bivariate correlations were found between personality and performance scores. Hierarchical multiple regression analyses revealed that a number of the scales from the 15FQ+ contributed to significantly predicting four of the performance competency dimensions, but that the CPAI-2 indigenous scales contributed no incremental validity in performance prediction over and above the 15FQ+. Results are discussed in the light of previous research and a call made for continued research to further develop and increase the reliability of the Chinese instruments used in the study and to enable generalization of the findings with confidence.

Bias, precision and heritability of self-reported and clinically measured height in Australian twins

Many studies of quantitative and disease traits in human genetics rely upon self-reported measures. Such measures are based on questionnaires or interviews and are often cheaper and more readily available than alternatives. However, the precision and potential bias cannot usually be assessed. Here we report a detailed quantitative genetic analysis of stature. We characterise the degree of measurement error by utilising a large sample of Australian twin pairs (857 MZ, 815 DZ) with both clinical and self-reported measures of height. Self-report height measurements are shown to be more variable than clinical measures. This has led to lowered estimates of heritability in many previous studies of stature. In our twin sample the heritability estimate for clinical height exceeded 90%. Repeated measures analysis shows that 2-3 times as many self-report measures are required to recover heritability estimates similar to those obtained from clinical measures. Bivariate genetic repeated measures analysis of self-report and clinical height measures showed an additive genetic correlation > 0.98. We show that the accuracy of self-report height is upwardly biased in older individuals and in individuals of short stature. By comparing clinical and self-report measures we also showed that there was a genetic component to females systematically reporting their height incorrectly; this phenomenon appeared to not be present in males. The results from the measurement error analysis were subsequently used to assess the effects of error on the power to detect linkage in a genome scan. Moderate reduction in error (through the use of accurate clinical or multiple self-report measures) increased the effective sample size by 22%; elimination of measurement error led to increases in effective sample size of 41%.

Evaluation of the indirect measures of rock brittleness and fracture toughness in rock cutting

Performance prediction models for partial face mechanical excavators, when developed in laboratory conditions, depend on relating the results of a set of rock property tests and indices to specific cutting energy (SE) for various rock types. There exist some studies in the literature aiming to correlate the geotechnical properties of intact rocks with the SE, especially for massive and widely jointed rock environments. However, those including direct and/or indirect measures of rock fracture parameters such as rock brittleness and fracture toughness, along with the other rock parameters expressing different aspects of rock behavior under drag tools (picks), are rather limited. With this study, it was aimed to investigate the relationships between the indirect measures of rock brittleness and fracture toughness and the SE depending on the results of a new and two previous linear rock cutting programmes. Relationships between the SE, rock strength parameters, and the rock index tests have also been investigated in this study. Sandstone samples taken from the different fields around Ankara, Turkey were used in the new testing programme. Detailed mineralogical analyses, petrographic studies, and rock mechanics and rock cutting tests were performed on these selected sandstone specimens. The assessment of rock cuttability was based on the SE. Three different brittleness indices (B1, B2, and B4) were calculated for sandstones samples, whereas a toughness index (T-i), being developed by Atkinson et al.(1), was employed to represent the indirect rock fracture toughness. The relationships between the SE and the large amounts of new data obtained from the mineralogical analyses, petrographic studies, rock mechanics, and linear rock cutting tests were evaluated by using bivariate correlation and curve fitting techniques, variance analysis, and Student's t-test. Rock cutting and rock property testing data that came from well-known studies of McFeat-Smith and Fowell(2) and Roxborough and Philips(3) have also been employed in statistical analyses together with the new data. Laboratory tests and subsequent analyses revealed that there were close correlations between the SE and B4 whereas no statistically significant correlation has been found between the SE and T-i. Uniaxial compressive and Brazilian tensile strengths and Shore scleroscope hardness of sandstones also exhibited strong relationships with the SE. NCB cone indenter test had the greatest influence on the SE among the other engineering properties of rocks, confirming the previous studies in rock cutting and mechanical excavation. Therefore, it was recommended to employ easy-to-use index tests of NCB cone indenter and Shore scleroscope in the estimation of laboratory SE of sandstones ranging from very low to high strengths in the absence of a rock cutting rig to measure it until the easy-to-use universal measures of the rock brittleness and especially the rock fracture toughness, being an intrinsic rock property, are developed.

Urinary excretion of cadmium among Torres Strait Islanders (Australia) at risk of elevated dietary exposure through traditional foods

This study explored urinary cadmium levels among Torres Strait Islanders in response to concerns about potential health impact of high levels of cadmium in some traditional seafood (dugong and turtle liver and kidney). Cadmium levels were measured by inductively coupled mass spectrometry in de-identified urine samples collected during general screening programs in 1996 in two communities with varying dugong and turtle catch statistics. Statistical analysis was performed to identify links between cadmium levels and demographic and background health information. Geometric mean cadmium level among the sample group was 0.83 mu g/g creatinine with 12% containing over 2 mu g/g creatinine. Cadmium level was most strongly associated with age (46% of variation), followed by sex (females > males, 7%) and current smoking status (smokers > non-smokers, 4.7%). Adjusting model conditions suggested further positive associations between cadmium level and diabetes (p = 0.05) and residence in the predicted higher exposure community (p = 0.07). Positive correlations between cadmium and body fat in bivariate analysis were eliminated by control for age and sex. This study found only suggestive differences in cadmium levels between two communities with predicted variation in exposure from traditional foods. However, the data indicate that factors linked with higher cadmium accumulation overlap with those of renal disease risk (i.e. older, females, smokers, diabetes) and suggest that levels may be sufficient to contribute to renal pathology. More direct assessment of exposure and health risks of cadmium to Torres Strait Islanders is needed given the disproportionate level of diet-related disease and the cultural importance of dugong and turtle. This study highlights the need to consider social and cultural variation in exposure and to de. ne "safe'' cadmium levels during diabetes given its rising global prevalence.

INTELIGÊNCIA EMOCIONAL, CAPITAL PSICOLÓGICO E PERCEPÇÃO DE SUPORTE ORGANIZACIONAL EM GESTORES DO SEGMENTO DE SAÚDE

O setor de saúde é fortemente impactado por diversos fatores e é considerado um dos mais importantes ramos da economia brasileira.O profissional da área é desafiado a responder pela gestão de temas para os quais não foi desenvolvido em seu processo educacional acadêmico. Considerando que pessoas emocionalmente inteligentes e ao mesmo tempo portadores de estados psicológicos positivos, que integram o capital psicológico, possuem uma estrutura psíquica que lhes possibilite atingir posições de liderança, este estudo objetivou interpretar e discutir as correlações entre inteligência emocional, capital psicológico, e percepção do suporte organizacional. Participaram do estudo 123 gestores com formação acadêmica em saúde e experiência em organizacões do segmento saúde. A coleta de dados foi realizada através de questionário eletrônico auto aplicável e os dados foram submetidos a análise descritiva e bivariada através do software SPSS em sua versão 19.0. Evidenciou-se que estes profissionais possuem em maior evidência a habilidade da inteligência emocional de autoconciencia, por outro lado apresentam limitações na disponibilidade e no estabelecimento das relações pessoais (sociabilidade) tão relevantes no processo de gestão. Já as dimensões relativas a capital psicológico, voltadas para o desempenho no trabalho, demonstraram que este profissional é confiante na sua capacidade de contribuição com os objetivos da empresa, bem como de superar os possíveis obstáculos inerentes a sua atividade laboral. Soma-se a seu capital psicológico a percepção de suporte que a organização possa lhe oferecer, quando necessitar de apoio para sentir-se bem e realizar suas tarefas.

AS RELAÇÕES ENTRE BEM-ESTAR NO TRABALHO E PARTICIPAÇÃO EM PROGRAMAS ORGANIZACIONAIS DE PROMOÇÃO DA SAÚDE

No campo científico, a busca por uma maior compreensão acerca de bem-estar no âmbito do trabalho é a tônica do momento, reunindo estudiosos das mais diferentes áreas que demonstram interesse pelo tema. No contexto empresarial, o papel dos programas de promoção da saúde e qualidade de vida torna-se marcante quando se deseja o crescimento da produtividade e do bem-estar dos trabalhadores, considerando a obtenção de resultados crescentes, pela empresa, como fundamentais para que as melhorias nas condições, organização e relações de trabalho ocorram permanentemente. Ou seja, as empresas entendem que com o investimento nesses programas a produtividade deve aumentar, gerando recursos, para que esta se sinta estimulada a continuar investindo no bem-estar dos empregados. Este estudo teve como objetivo promover uma análise sobre as relações entre bem-estar no trabalho, representado por satisfação com o trabalho, envolvimento com o trabalho e comprometimento organizacional afetivo; e freqüência a programas organizacionais de promoção da saúde. A amostra foi constituída por 117 trabalhadores de uma indústria multinacional química e farmacêutica, situada na Grande São Paulo, sendo 53 do sexo masculino e 64 do sexo feminino, com idade média de 30,28 anos, dos quais 63 eram solteiros, 46 casados e oito registram outro estado civil. Para desenvolvimento deste estudo, utilizou-se como instrumento um questionário composto por quatro escalas que mediram satisfação no trabalho, envolvimento com o trabalho, comprometimento organizacional afetivo e freqüência de participação em programas de promoção da saúde, realizados na empresa. Todos os dados recolhidos por meio do instrumento eram numéricos, o que permitiu sua análise eletrônica pelo SPSS, versão 13.0 para Windows. Nessa categoria de dados incluem-se os de descrição da amostra, os referentes a bem-estar no trabalho e freqüência aos programas de promoção da saúde. Foi criado um banco de dados para realização das análises descritivas (freqüências, percentuais, médias e desvios-padrão) e de correlação bivariada (r de Pearson). Os dados que permitiram descrever os programas de promoção da saúde promovidos pela empresa foram obtidos por meio de entrevista com a gerente de responsabilidade social, análise do relatório da empresa e de folhetos elaborados para divulgação e registro desses programas. Um total de cinco categorias de programas foi identificado: benefícios, atividades físicas, saúde, atividades culturais/lazer e ações comunitárias. A maior freqüência aos programas ocorreu na categoria benefícios, pela presença constante no restaurante da empresa. Os resultados deste estudo revelaram que grande parcela do bem-estar no trabalho especialmente no que tange o envolvimento com o trabalho, comprometimento afetivo com a organização, bem como satisfações com os colegas, com a chefia e com o próprio trabalho praticamente independe dos programas de promoção da saúde promovidos pela empresa. Por outro lado, participação em programas de promoção da saúde que incluem as categorias de benefícios, saúde e ações comunitárias, relacionou-se a satisfações com promoções e com salário

Combining the wavelet transform and forecasting models to predict gas forward prices

This paper presents a forecasting technique for forward energy prices, one day ahead. This technique combines a wavelet transform and forecasting models such as multi- layer perceptron, linear regression or GARCH. These techniques are applied to real data from the UK gas markets to evaluate their performance. The results show that the forecasting accuracy is improved significantly by using the wavelet transform. The methodology can be also applied to forecasting market clearing prices and electricity/gas loads.

Energy forward price prediction with a hybrid adaptive model

This paper presents a forecasting technique for forward electricity/gas prices, one day ahead. This technique combines a Kalman filter (KF) and a generalised autoregressive conditional heteroschedasticity (GARCH) model (often used in financial forecasting). The GARCH model is used to compute next value of a time series. The KF updates parameters of the GARCH model when the new observation is available. This technique is applied to real data from the UK energy markets to evaluate its performance. The results show that the forecasting accuracy is improved significantly by using this hybrid model. The methodology can be also applied to forecasting market clearing prices and electricity/gas loads.

Modeling equity market integration using smooth transition analysis:a study of Eastern European stock markets

This paper assesses the extent to which the equity markets of Hungary, Poland the Czech Republic and Russia have become less segmented. Using a variety of tests it is shown there has been a consistent increase in the co-movement of some Eastern European markets and developed markets. Using the variance decompositions from a vector autoregressive representation of returns it is shown that for Poland and Hungary global factors are having an increasing influence on equity returns, suggestive of increased equity market integration. In this paper we model a system of bivariate equity market correlations as a smooth transition logistic trend model in order to establish how rapidly the countries of Eastern Europe are moving away from market segmentation. We find that Hungary is the country which is becoming integrated the most quickly. © 2005 ELsevier Ltd. All rights reserved.