972 resultados para Factor scores
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The aim of this study was to investigate the subjective experience of acquired deafness using quantitative (questionnaire) and qualitative (interview) methods. This paper presents findings from the questionnaire data. Eighty-seven people (of whom 38 had acquired a profound loss) participated in the study. The questionnaire contained items designed to examine both audiological and non-audiological aspects of deafened people's experiences. It also sought to measure the extent to which those aspects affect their quality of life. The questionnaire included three variables (i.e. reported frequency and impact of depression, and overall effect of deafness on one's life) as broad indicators of adjustment. Seventy-three respondents (including all but one of the profound group) completed the questionnaire. Factor analysis of the questionnaire data identified six major themes (with variance >10%) underlying the personal experience of acquired deafness. Three themes-communicative deprivation, restriction, and malinteraction by hearing people-dealt with observable aspects of respondents' experience. Multiple regression found that these factor themes associated with biomedical variables. The remaining three themes dealt with less tangible aspects of the deafness experience. These themes-feelings of distress in interaction, feelings of abandonment and benefit from positive experiences-did not associate with biomedical variables. Finally, multiple regression indicates that respondents' factor scores predict the impact of deafness at least as strongly as their audiological and social characteristics.
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Empirically derived phenotypic measurements have the potential to enhance gene-finding efforts in schizophrenia. Previous research based on factor analyses of symptoms has typically included schizoaffective cases. Deriving factor loadings from analysis of only narrowly defined schizophrenia cases could yield more sensitive factor scores for gene pathway and gene ontology analyses. Using an Irish family sample, this study 1) factor analyzed clinician-rated Operational Criteria Checklist items in cases with schizophrenia only, 2) scored the full sample based on these factor loadings, and 3) implemented genome-wide association, gene-based, and gene-pathway analysis of these SCZ-based symptom factors (final N= 507). Three factors emerged from the analysis of the schizophrenia cases: a manic, a depressive, and a positive symptom factor. In gene-based analyses of these factors, multiple genes had q<. 0.01. Of particular interest are findings for PTPRG and WBP1L, both of which were previously implicated by the Psychiatric Genomics Consortium study of SCZ; results from this study suggest that variants in these genes might also act as modifiers of SCZ symptoms. Gene pathway analyses of the first factor indicated over-representation of glutamatergic transmission, GABA-A receptor, and cyclic GMP pathways. Results suggest that these pathways may have differential influence on affective symptom presentation in schizophrenia.
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In this paper we compare conceptualising single factor technical and allocative efficiency as indicators of a single latent variable, or as separate observed variables. In the former case, the impacts on both efficiency types are analysed by means of structural equation modeling (SEM), in the latter by seemingly unrelated regression (SUR). We compare estimation results of the two approaches based on a dataset on single factor irrigation water use efficiency obtained from a survey of 360 farmers in the Guanzhong Plain, China. The main methodological findings are that SEM allows identification of the most important dimension of irrigation water efficiency (technical efficiency) via comparison of their factor scores and reliability. Moreover, it reduces multicollinearity and attenuation bias. It thus is preferable to SUR. The SEM estimates show that perception of water scarcity is the most important positive determinant of both types of efficiency, followed by irrigation infrastructure, income and water price. Furthermore, there is a strong negative reverse effect from efficiency on perception.
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BACKGROUND AND AIMS: Inflammatory bowel disease (IBD) frequently manifests during childhood and adolescence. For providing and understanding a comprehensive picture of a patients' health status, health-related quality of life (HRQoL) instruments are an essential complement to clinical symptoms and functional limitations. Currently, the IMPACT-III questionnaire is one of the most frequently used disease-specific HRQoL instrument among patients with IBD. However, there is a lack of studies examining the validation and reliability of this instrument. METHODS: 146 paediatric IBD patients from the multicenter Swiss IBD paediatric cohort study database were included in the study. Medical and laboratory data were extracted from the hospital records. HRQoL data were assessed by means of standardized questionnaires filled out by the patients in a face-to-face interview. RESULTS: The original six IMPACT-III domain scales could not be replicated in the current sample. A principal component analysis with the extraction of four factor scores revealed the most robust solution. The four factors indicated good internal reliability (Cronbach's alpha=.64-.86), good concurrent validity measured by correlations with the generic KIDSCREEN-27 scales and excellent discriminant validity for the dimension of physical functioning measured by HRQoL differences for active and inactive severity groups (p<.001, d=1.04). CONCLUSIONS: This study with Swiss children with IBD indicates good validity and reliability for the IMPACT-III questionnaire. However, our findings suggest a slightly different factor structure than originally proposed. The IMPACT-III questionnaire can be recommended for its use in clinical practice. The factor structure should be further examined in other samples.
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In an earlier investigation (Burger et al., 2000) five sediment cores near the Rodrigues Triple Junction in the Indian Ocean were studied applying classical statistical methods (fuzzy c-means clustering, linear mixing model, principal component analysis) for the extraction of endmembers and evaluating the spatial and temporal variation of geochemical signals. Three main factors of sedimentation were expected by the marine geologists: a volcano-genetic, a hydro-hydrothermal and an ultra-basic factor. The display of fuzzy membership values and/or factor scores versus depth provided consistent results for two factors only; the ultra-basic component could not be identified. The reason for this may be that only traditional statistical methods were applied, i.e. the untransformed components were used and the cosine-theta coefficient as similarity measure. During the last decade considerable progress in compositional data analysis was made and many case studies were published using new tools for exploratory analysis of these data. Therefore it makes sense to check if the application of suitable data transformations, reduction of the D-part simplex to two or three factors and visual interpretation of the factor scores would lead to a revision of earlier results and to answers to open questions . In this paper we follow the lines of a paper of R. Tolosana- Delgado et al. (2005) starting with a problem-oriented interpretation of the biplot scattergram, extracting compositional factors, ilr-transformation of the components and visualization of the factor scores in a spatial context: The compositional factors will be plotted versus depth (time) of the core samples in order to facilitate the identification of the expected sources of the sedimentary process. Kew words: compositional data analysis, biplot, deep sea sediments
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Several methods have been suggested to estimate non-linear models with interaction terms in the presence of measurement error. Structural equation models eliminate measurement error bias, but require large samples. Ordinary least squares regression on summated scales, regression on factor scores and partial least squares are appropriate for small samples but do not correct measurement error bias. Two stage least squares regression does correct measurement error bias but the results strongly depend on the instrumental variable choice. This article discusses the old disattenuated regression method as an alternative for correcting measurement error in small samples. The method is extended to the case of interaction terms and is illustrated on a model that examines the interaction effect of innovation and style of use of budgets on business performance. Alternative reliability estimates that can be used to disattenuate the estimates are discussed. A comparison is made with the alternative methods. Methods that do not correct for measurement error bias perform very similarly and considerably worse than disattenuated regression
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The variety and quality of the tenant mix within a shopping centre is a key concern in shopping centre management. Tenant mix determines the extent of externalities between outlets in the centre, helps establish the image of the centre and, as a result, determines the attractiveness of the centre for consumers. This then translates into sales and rents. However, the management of tenant mix has largely been based on perceived “optimum” arrangements and industry rules of thumb. This paper attempts to model the impact of tenant mix on the rent paid by retailers in larger UK shopping centres and, hence, the returns made by shopping centre landlords. It extends work on shopping centre rent determination (see Working Paper 10/03) utilising a database of 148 regional shopping centres in the UK, with detailed data for over 1900 tenants. Econometric models test the relationship between rental levels and the levels of retail concentration and diversity, while controlling for a range of continuous and qualitative characteristics of each tenant, each retail product, and each shopping centre. Factor analysis is then used to extract the core retail and service categories from the tenant lists of the 148 shopping centres. The factor scores from these core retailer factors are then tested against rent payable. The results from the empirical analysis allow us to generate some clear analytical and empirical implications for optimal retail management.
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Background: The relationship between continuity of care and user characteristics or outcomes has rarely been explored. The ECHO study operationalized and tested a multi-axial definition of continuity of care, producing a seven-factor model used here. Aims: To assess the relationship between user characteristics and established components of continuity of care, and the impact of continuity on clinical and social functioning. Methods: The sample comprised 180 community mental health team users with psychotic disorders who were interviewed at three annual time-points, to assess their experiences of continuity of care and clinical and social functioning. Scores on seven continuity factors were tested for association with user-level variables. Results: Improvement in quality of life was associated with better Experience & Relationship continuity scores (better user-rated continuity and therapeutic relationship) and with lower Meeting Needs continuity factor scores. Higher Meeting Needs scores were associated with a decrease in symptoms. Conclusion: Continuity is a dynamic process, influenced significantly by care structures and organizational change.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Measures of mortality represent one of the most important indicators of health conditions. For comprising the larger rate of deaths, the study of mortality in the elderly population is regarded as essential to understand the health situation. In this sense, the present study aims to analyze the mortality profile of the population from 60 to 69 (young elders) and older than 80 years old (oldest old) in the Rio Grande do Norte state (Brazil) in the period 2001 to 2011, and to identify the association with contextual factors and variables about the quality of the Mortality Information System (SIM). For this purpose, Mortality Proportional (MP) was calculated for the state and Specific Mortality Rate by Age (CMId) , according to chapters of ICD- 10, to the municipalities of Rio Grande do Norte , through data from the Mortality Information System (SIM) and the Brazilian Institute of Geography and Statistics (IGBE). In order to identify groups of municipalities with similar mortality profiles, Nonhierarchical Clustering K-means method was applied and the Factor Analysis by the Principal Components Analysis was resort to reduce contextual variables. The spatial distribution of these groups and the factors were visualized using the Spatial Analysis Areas technique. During the period investigated, 21,813 younger elders deaths were recorded , with a predominance of deaths from circulatory diseases (32.75%) and neoplasms (22.9 %) . Among the oldest old, 50,637 deaths were observed, which 35.26% occurred because of cardiovascular diseases and 17.27% of ill-defined causes. Clustering Analysis produced three clusters to the two age groups and Factor Analysis reduced the contextual variables into three factors, also the sum of the factor scores was considered. Among the younger elders, the groups are called misinformation profile, development profile and development paradox, which showed a statistically significant association with education and poverty and extreme poverty factors, factorial sum and the variable related to underreporting of deaths. Misinformation profile remained in the oldest old group, accompanied by the epidemiological transition profile and the epidemiological paradox, that were statistically associated with the development and health factor, as well as with the variables that indicate the SIM quality: proportion of blank fields about the schooling and underreporting. It proposed that the mortality profiles of the younger elders and oldest old differ on the importance of the basic causes and that are influenced by different contextual aspects , observing that 60 to 69 years group is more affected by such aspects. Health inequalities can be reduced by measures aimed to improve levels of education and poverty, especially in younger elders, and by optimizing the use of health services, which is more associated to the oldest old health situation. Furthermore, it is important to improve the quality of information for the two age groups
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Estudos sobre a violência urbana vêm sendo realizados no Brasil buscando encontrar correlações e associações significativas entre taxas de homicídio e/ou tráfico de drogas e indicadores sociais ou econômicos. Esses estudos costumam utilizar como unidade de análise as divisões administrativas oficiais: regiões, estados, municípios e bairros. Entretanto, não tem sido tarefa simples o desafio de encontrar evidências empíricas a respeito da relação positiva entre fenômenos socioeconômicos e taxas de homicídio e/ou tráfico de drogas no nível intraurbano. Neste sentido este trabalho tem o objetivo de estudar as relações espaciais e multivariada dos crimes de tráfico de drogas e homicídio e a urbanizaçã do município de Belém-PA. Inicialmente aplicou-se a técnica estatística análise descritiva para evidenciar as taxas dos crimes de tráfico de drogas e homicídio nos bairros de Belém. Em seguida, aplicou-se a técnica estatística multivariada análise fatorial, o que permitiu estimar os escores fatoriais, a partir dos quais pôde-se construir o índice de qualidade de urbanização (IQU), baseado em indicadores socioeconômicos e ambientais da cidade de Belém, permitindo a classificação dos bairros em péssimo, ruim, regular, bom e ótimo, de acordo com os atributos de cada bairro. Em seguida, de posse do índice de urbanização e das taxas de tráfico de drogas e homicídio pôde-se submeter esses dados a técnica estatística multivariada análise de correspondência, cujo objetivo foi averiguar o nível de correlação (associação positiva ou negativa) entre essas variáveis. Dessa maneira, dentre os principais resultados pôde-se observar que bairros com baixa urbanização estão associados à moderada ou alta taxa de tráfico de drogas e alta taxa de homicádio. Bairros com alta urbanização estão associados à baixa taxa de tráfico de drogas e baixa taxa de homicídio. Assim como, bairros com baixa taxa de tráfico de drogas possuem baixa taxa de homicídio e bairros com alta taxa de tráfico de drogas possuem alta taxa de homicídio no município de Belém.
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Sao Paulo state (Brazil) has one of the most overpopulated coastal zones in South America, where previous studies have already detected sediment and water contamination. However, biological-based monitoring considering signals of xenobiotic exposure and effects are scarce. The present study employed a battery of biomarkers under field conditions to assess the environmental quality of this coastal zone. For this purpose, the activity of CYP 450, antioxidant enzymes, DNA damage, lipid peroxidation and lysosomal membrane were analysed in caged mussels and integrated using Factorial Analysis. A representation of estimated factor scores was performed in order to confirm the factor descriptions characterizing the studied areas. Biomarker responses indicated signals of mussels` impaired health during the monitoring, which pointed to the impact of different sources of contaminants in the water quality and identified critical areas. This integrated approach produced a rapid, sensitive and cost-effective assessment, which could be incorporated as a descriptor of environmental status in future coastal zones biomonitoring. (C) 2011 Elsevier Inc. All rights reserved.
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This study aimed to provide the first biomonitoring integrating biomarkers and bioaccumulation data in Sao Paulo coast, Brazil and, for this purpose, a battery of biomarkers of defense mechanisms was analyzed and linked to contaminants' body burden in a weigh-of-evidence approach. The brown mussel Perna perna was selected to be transplanted from a farming area (Caraguatatuba) to four possibly polluted sites: Engenho D'Agua, DTCS (Dutos e Terminais do Centro-Oeste de Sao Paulo) oil terminal (Sao Sebastiao zone), Palmas Island, and Itaipu (It; Santos Bay zone). After 3 months of exposure in each season, mussels were recollected and the cytochrome P4501A (CYP1A)- and CYP3A-like activities, glutathione-S-transferase and antioxidants enzymes (catalase, glutathione peroxidase, and glutathione reductase) were analyzed in gills. The concentrations of polycyclic aromatic hydrocarbons, linear alkylbenzenes, and nonessential metals (Cr, Cd, Pb, and Hg) in whole tissue were also analyzed and data were linked to biomarkers' responses by multivariate analysis (principal component analysisfactor analysis). A representation of estimated factor scores was performed to confirm the factor descriptions and to characterize the studied stations. Biomarkers exhibited most significant alterations all year long in mussels transplanted to It, located at Santos Bay zone, where bioaccumulation of organic and inorganic compounds was detected. This integrated approach using transplanted mussels showed satisfactory results, pointing out differences between sites, seasons, and critical areas, which could be related to land-based contaminants' sources. The influence of natural factors and other contaminants (e.g., pharmaceuticals) on biomarkers' responses are also discussed.
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Objective: to evaluate the psychopathological profile in primary Restless Legs Syndrome (p-RLS) patients with and without nocturnal eating disorder (NED), analysing obsessive-compulsive traits, mood and anxiety disorder, and the two domains of personality proposed by Cloninger, temperament and character. Methods: we tested ten p-RLS patients without NED, ten p-RLS patients with NED and ten healthy control subjects, age and sex-matched, using Hamilton Depression and Anxiety Rating Scales, State-Trait Anxiety Inventory, Maudsley Obsessive Compulsive Inventory (MOCI) and Temperament and Character Inventory - revised (TCI). Results: p-RLS patients, particularly those with NED, had increased anxiety factor scores. MOCI-total, doubting and checking compulsion, and TCI-harm avoidance scores were significantly higher in p-RLS patients with NED. p-RLS patients without NED had significantly higher MOCI-doubting scores and a trend toward higher checking compulsion and harm avoidance scores with an apparent grading from controls to p-RLS patients without NED to p-RLS with NED. Conclusions: higher harm avoidance might predispose to display obsessive-compulsive symptoms, RLS and then, with increasing severity, compulsive nocturnal eating. RLS and NED could represent a pathological continuum in which a dysfunction in the limbic system, possibly driven by a dopaminergic dysfunction, could be the underlying pathophysiological mechanism.