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Selected Variables (selected + variable)
Selected AbstractsPredictors of anemia in patients on hemodialysisHEMODIALYSIS INTERNATIONAL, Issue 3 2009Willy AASEBØ Abstract Even though the use of erythropoietin and intravenous iron has improved the treatment of anemia in hemodialysis patients, a considerable proportion of these patients still have anemia. The aim of this study was to identify predictors of anemia in a hemodialysis population. In a single-center hemodialysis unit, all patients were studied with blood tests and their medication recorded during a period of 22 months. Correlations with hemoglobin (Hb) were performed with a simple regression or a t test. Variables that reached 5% significance were entered in a multiple regression analysis. Selected variables were presented in quartiles with levels of Hb. Mean Hb was 11.3 g/dL, and 53 patients (40%) had Hb<11.0 g/dL. In the simple regression analysis Hb correlated positively with s-iron, CHr, s-albumin, and doses of sevelamer, and negatively with sedimentation rate (SR), ferritin, base excess, and doses of erythropoietin. In the multiple regression analysis erythrocytes SR was the only variable that remained significant. Elevated SR is the strongest predictor of anemia in hemodialysis patients receiving adequate treatment with erythropoietin and intravenous iron. Patients using high doses of sevelamer had higher Hb levels than patients using low doses. [source] Patterns of Treatment Services and Costs for Young Offenders with Mental DisordersJOURNAL OF CHILD AND ADOLESCENT PSYCHIATRIC NURSING, Issue 3 2005Deborah Shelton PhD PROBLEM:,This study describes mental health treatment service delivery patterns and costs for youth in a juvenile justice system. METHODS:,A secondary data analysis on a random sample of juvenile offenders (N = 312) was completed. Service patterns and costs were described. Selected variables were examined for their ability to predict who received treatment. FINDINGS:,Only 23% of youth diagnosed with a mental disorder received any treatment. Older youth and African American youth received fewer services, and race was the only significant predictor for receiving treatment (p = .001). CONCLUSIONS:,Mental health treatment services were scarce, and the data reflects a race bias in the provision of services. Although the law protects the right to treatment for these individuals, provision of services remains a challenge. [source] Cytopathologic differential diagnosis of malignant mesothelioma, adenocarcinoma and reactive mesothelial cells: A logistic regression analysis,DIAGNOSTIC CYTOPATHOLOGY, Issue 1 2009Ebru Cakir M.D. Abstract Distinguishing malignant mesothelioma, adenocarcinoma and reactive mesothelial proliferation in both cytologic and surgical pathologic specimens is often a diagnostic challenge. Conventional cytomorphologic assessment is an important step in the differential diagnosis of these entities. The pleural effusion cytologies from 40 cases of malignant mesothelioma, 40 cases of adenocarcinoma and 30 cases of reactive mesothelial proliferation diagnosed between 1997 and 2007 were reviewed. Twenty-seven cytologic features which are regarded as useful in the differential diagnosis of mesothelioma, adenocarcinoma and benign mesothelial proliferation were assessed. These cytologic features were subjected to a stepwise logistic regression analysis. Three features were selected to distinguish malignant mesothelioma from adenocarcinoma: giant atypical mesothelial cell (P = 0.0001), nuclear pleomorphism (P = 0.0001) and acinar structures (P = 0.0001), the latter two being characteristics of adenocarcinoma. The variables selected to differentiate malignant mesothelioma from reactive mesothelial cells were: cell ball formation (P = 0.0001), cell in cell engulfment (P = 0.0001) and monolayer cell groups (P = 0.0001), the latter being a feature of benign mesothelial proliferation. When these selected variables were subjected to a stepwise logistic regression analysis, the logistic model correctly predicted 90% of cases of benign mesothelial proliferation versus 97.5% of malignant mesothelioma and 92.5% of malignant mesothelioma versus 92.5% of adenocarcinoma. Conventional cytomorphologic assessment is the first step to establish an accurate diagnosis in pleural effusions. Several cytologic features have predictive value to seperate malignant mesothelioma from adenocarcinoma and reactive mesothelial proliferation. Diagn. Cytopathol. 2009. © 2008 Wiley-Liss, Inc. [source] Spatial, environmental and human influences on the distribution of otter (Lutra lutra) in the Spanish provincesDIVERSITY AND DISTRIBUTIONS, Issue 3 2001Ana Márcia Barbosa Abstract In a previous survey of otters (Lutra lutra L. 1758) in Spain, different causes were invoked to explain the frequency of the species in each province. To find common causes of the distribution of the otter in Spain, we recorded a number of spatial, environmental and human variables in each Spanish province. We then performed a stepwise linear multiple regression of the proportion of positive sites of otter in the Spanish provinces separately on each of the three groups of variables. Geographic longitude, January air humidity, soil permeability and highway density were the variables selected. A linear regression of the proportion of otter presence on these variables explained 62.4% of the variance. We then used the selected variables in a partial regression analysis to specify which proportions of the variation are explained exclusively by spatial, environmental and human factors, and which proportions are attributable to interactions between these components. Pure environmental effects accounted for only 5.5% of the variation, while pure spatial and pure human effects explained 18% and 9.7%, respectively. Shared variation among the components totalled 29.2%, of which 10.9% was explained by the interaction between environmental and spatial factors. Human factors explained globally less variance than spatial and environmental ones, but the pure human influence was higher than the pure environmental one. We concluded that most of the variation in the proportion of occurrences of otter in Spanish provinces is spatially structured, and that environmental factors have more influence on otter presence than human ones; however, the human influence on otter distribution is less structured in space, and thus can be more disruptive. This effect of large infrastructures on wild populations must be taken into account when planning large-scale conservation policies. [source] Measurement of pressure and flow rates during irrigation of a root canal ex vivo with three endodontic needlesINTERNATIONAL ENDODONTIC JOURNAL, Issue 7 2007C. Boutsioukis Abstract Aim, To monitor ex vivo intra-canal irrigation with three endodontic needles (25, 27 and 30 gauge) and compare them in terms of irrigant flow rate, intra-barrel pressure, duration of irrigation and volume of irrigant delivered. Methodology, A testing system was constructed to allow measurement of selected variables with pressure and displacement transducers during ex vivo intra-canal irrigation with a syringe and three different needles (groups A, B, C) into a prepared root canal. Ten specialist endodontists performed the irrigation procedure. Each operator performed ten procedures with each needle. Data recorded by the transducers were analysed using Friedman's test, Wilcoxon Signed Rank test, Mann,Whitney U -test and Kendall's Tb test. The level of significance was set to 95%. Results, Significant differences were detected among the three needles for most variables. Duration of delivery and flow rates significantly decreased as the needle diameter increased, whilst pressure increased up to 400,550 kPa. Gender of the operator had a significant impact on the results. Experience of the operators (years) were negatively correlated to volume of irrigant (all groups), to the duration of delivery (groups A, B) and to the average flow rate (group A). Conclusions, Finer diameter needles require increased effort to deliver the irrigant and result in higher intra-barrel pressure. The syringe and needles used tolerated the pressure developed. Irrigant flow rate should be considered as a factor directly influencing flow beyond the needle. Wide variations of flow rate were observed among operators. Syringe irrigation appears difficult to standardize and control. [source] Impacts of health and environmental consciousness on young female consumers' attitude towards and purchase of natural beauty productsINTERNATIONAL JOURNAL OF CONSUMER STUDIES, Issue 6 2009Soyoung Kim Abstract This study investigated young female consumers' beauty product shopping behavioural patterns, their perceived importance of product attributes, and their attitude towards and purchase of natural beauty products. This study also examines whether consumers' product attitudes and shopping behaviours are influenced by their health and environmental consciousness. Data were collected from a convenience sample of 210 female college students enrolled at a south-eastern university in the US. In order to examine the impacts of both health and environmental consciousness on other selected variables, the respondents were divided into four groups based on their scores on the two variables, and a series of analysis of variance were conducted to compare characteristics of the four groups. The results showed that health and environmental consciousness significantly influenced the importance placed on beauty product attributes. Additionally, those with a high level of both health and environmental consciousness were significantly more positive in their evaluations than those with low scores on both variables in their perceptions of natural beauty products. Those with low scores on both variables were significantly less willing than the other groups to pay more for natural beauty products. Analysis of variance results also indicated that the two groups with a high level of environmental consciousness purchased natural beauty products more frequently than those with a low level of health and environmental consciousness, indicating a relatively stronger impact of environmental consciousness than health consciousness on frequency of natural beauty product purchases. Health and environmental consciousness were both significantly related to a respondent's perceived level of knowledge of beauty products and ability to distinguish natural from conventional beauty products. [source] A variable selection strategy for supervised classification with continuous spectroscopic dataJOURNAL OF CHEMOMETRICS, Issue 2 2004Ulf Indahl Abstract In this paper we present a new variable selection method designed for classification problems where the X data are discretely sampled from continuous curves. For such data the loading weight vectors of a PLS discriminant analysis inherit the continuous behaviour, making the idea of local peaks meaningful. For successive components the local peaks are checked for importance before entering the set of selected variables. Our examples with NIR/NIT show that substantial simplification of the X space can be obtained without loss of classification power when compared with ,benchmark full-spectrum' methods. Copyright © 2004 John Wiley & Sons, Ltd. [source] The importance of weighted variables to OPEC's production quota allocationOPEC ENERGY REVIEW, Issue 2 2003Mahmoud Al-Osaimy The objective of this paper is to estimate a weighted variables formula that could be used to calculate OPEC quota distribution. Instead of assigning an arbitrary weight to each of the selected variables included in the formula, we estimate weights based on historical data, using regression analysis. Six national characteristics of OPEC Member Countries, related to oil and socio-economic factors, are considered in the estimation. Time-series are used from 1982 to 2001, for each OPEC Member Country. The results show that the estimated weights are sensitive to the periods considered in the analysis, as well as the number of variables selected. However, there is no specific optimum way of dealing with the sensitive, complex quota issue. [source] Differences Between Mistimed and Unwanted Pregnancies Among Women Who Have Live BirthsPERSPECTIVES ON SEXUAL AND REPRODUCTIVE HEALTH, Issue 5 2004Denise V. D'Angelo CONTEXT: Mistimed and unwanted pregnancies that result in live births are commonly considered together as unintended pregnancies, but they may have different precursors and outcomes METHODS: Data from 15 states participating in the 1998 Pregnancy Risk Assessment Monitoring System were used to calculate the prevalence of intended, mistimed and unwanted conceptions, by selected variables. Associations between unintendedness and women's behaviors and experiences before, during and after the pregnancy were assessed through unadjusted relative risks. RESULTS: The distribution of intended, mistimed and unwanted pregnancies differed on nearly every variable examined; risky behaviors and adverse experiences were more common among women with mistimed than intended pregnancies and were most common among those whose pregnancies were unwanted. The likelihood of having an unwanted rather than mistimed pregnancy was elevated for women 35 or older (relative risk, 2.3) and was reduced for those younger than 25 (0.8); the pattern was reversed for the likelihood of mistimed rather than intended pregnancy (0.5 vs. 1.7,2.7). Parous women had an increased risk of an unwanted pregnancy (2.1,4.0) but a decreased risk of a mistimed one (0.9). Women who smoked in the third trimester, received delayed or no prenatal care, did not breastfeed, were physically abused during pregnancy, said their partner had not wanted a pregnancy or had a low-birth-weight infant had an increased risk of unintended pregnancy; the size of the increase depended on whether the pregnancy was unwanted or mistimed CONCLUSION: Clarifying the difference in risk between mistimed and unwanted pregnancies may help guide decisions regarding services to women and infants [source] Cytopathologic differential diagnosis of small cell carcinoma and poorly differentiated non-small cell carcinoma in bronchial lavage specimens using a regression analysisAPMIS, Issue 2 2010EBRU CAKIR Cakir E, Demirag F, Aydin M. Cytopathologic differential diagnosis of small cell carcinoma and poorly differentiated non-small cell carcinoma in bronchial lavage specimens using a regression analysis. APMIS 2010; 118: 150,55. The aim of this study was to determine the most significant cytologic features to differentiate small cell carcinoma (SCC) from poorly differentiated non-small cell carcinoma (NSCC) in bronchial lavage specimens. Bronchial lavage specimens from 35 SCC cases and 63 poorly differentiated NSCC cases were examined and the cytologic parameters reviewed retrospectively. Thirty-five cytologic features considered useful in differential diagnosis were assessed. Statistical analysis indicated that salt and pepper chromatin, small cell size and nuclear molding have more than 90% sensitivity and 70% specificity for SCC cases. Logistic regression analysis demonstrated that the most effective criteria to differentiate SCC from poorly differentiated NSCC are small cell size, salt and pepper chromatin, prominent nucleolus and papilla formation. When these selected variables were used, sensitivity for predicting SCC was 94.3% and specificity 96.8%, and sensitivity for predicting NSCC was 96.8% and specificity 94.3%. There are several cytologic features, which are highly sensitive and specific for distinguishing SCC from NSCC. Nuclear features such as chromatin pattern, and size of the nucleoli and nuclei are more valuable than cytoplasmic features to distinguish between the two. [source] ACCOUNTING FOR POPULATION AGEING IN TAX MICROSIMULATION MODELLING BY SURVEY REWEIGHTING,AUSTRALIAN ECONOMIC PAPERS, Issue 1 2006LIXIN CAI This paper investigates the use of sample reweighting, in a behavioural tax microsimulation model, to examine the implications for government taxes and expenditure of population ageing in Australia. First, a calibration approach to sample reweighting is described, producing new weights that achieve specified population totals for selected variables. Second, the performance of the Australian Bureau of Statistics' (ABS) weights provided with the 2000,2001 Survey of Income and Housing Cost (SIHC) was examined and it was found that reweighting does not improve the simulation outcomes for the 2001 situation, so the original ABS weights were retained for 2001. Third, the implications of changes in the age distribution of the population were examined, based on population projections to 2050. A ,pure' change in the age distribution was examined by keeping the aggregate population size fixed and changing only the relative frequencies in different age-gender groups. Finally, the effects of a policy change to benefit taper rates in Australia were compared for 2001 and 2050 population weights. It is suggested that this type of exercise provides an insight into the implications for government income tax revenue and social security expenditure of changes in the population, indicating likely pressures for policy changes. [source] Variable Selection for Logistic Regression Using a Prediction-Focused Information CriterionBIOMETRICS, Issue 4 2006Gerda Claeskens Summary In biostatistical practice, it is common to use information criteria as a guide for model selection. We propose new versions of the focused information criterion (FIC) for variable selection in logistic regression. The FIC gives, depending on the quantity to be estimated, possibly different sets of selected variables. The standard version of the FIC measures the mean squared error of the estimator of the quantity of interest in the selected model. In this article, we propose more general versions of the FIC, allowing other risk measures such as the one based on Lp error. When prediction of an event is important, as is often the case in medical applications, we construct an FIC using the error rate as a natural risk measure. The advantages of using an information criterion which depends on both the quantity of interest and the selected risk measure are illustrated by means of a simulation study and application to a study on diabetic retinopathy. [source] Costs and Risks of Segregating GM Wheat in CanadaCANADIAN JOURNAL OF AGRICULTURAL ECONOMICS, Issue 3 2006William W. Wilson An analytical model was developed to explore prospective costs and risks of alternative testing strategies for a marketing system in Canada which markets both genetically modified (GM) and Non-GM wheats. The problem is solved using stochastic optimization, base case results are defined, and sensitivities conducted to evaluate impacts of selected variables. Added costs include: testing, rejection, and a risk premium which is required for handlers to be indifferent between the current and the proposed dual system. Protocols would require testing at the point of loading at the primary elevator, and export elevator, and supplementing this information with some form of grower variety declaration. There are several sources of inherent risks in such a system. For buyers, the cumulative impact of these is the risk of receiving GM content in a Non-GM shipment. For sellers, it is the risk of having a Non-GM shipment rejected. For sellers, the risk of rejection was typically less than 2%, and for buyers, the risk was typically less than 0.02%. Nous avons élaboré un modèle analytique pour explorer les coûts et les risques potentiels de la mise en place de nouvelles stratégies pour analyser le grain si le Canada décidait de commercialiser du blé génétiquement modifié (GM) et du blé non génétiquement modifié (NGM). Le problème est résolu à l'aide d'une optimisation stochastique; des scénarios de référence sont définis et des tests de sensitivité sont effectués pour évaluer l'impact de variables sélectionnées. Les coûts supplémentaires comprennent les coûts d'analyses, les coûts liés au rejet ainsi qu'une prime de risque exigée pour que les manutentionnaires demeurent indifférents entre le système actuel et le système double proposé. Les protocoles obligeraient la tenue d'analyses au point de chargement du silo primaire ainsi qu'au silo terminal, auxquelles s'ajouterait une certaine forme de déclaration du céréaliculteur sur la variété. Ce genre de système comporte plusieurs sources de risques inhérents. Pour les acheteurs, l'impact cumulatif est le risque de recevoir un chargement de blé NGM contenant du blé GM. Pour les vendeurs, c'est le risque qu'un chargement de blé NGM soit rejeté. Pour les vendeurs, le risque de rejet était généralement inférieur à 2%, et pour les acheteurs, le risque était généralement inférieur à 0.02%. [source] Developmental, behavioural and somatic factors in pervasive developmental disorders: preliminary analysisCHILD: CARE, HEALTH AND DEVELOPMENT, Issue 1 2004P. Whiteley Abstract Objectives To ascertain the frequency of parental reporting of selected variables related to development, behaviour and physiology in subgroups diagnosed with pervasive developmental disorders (PDDs) and identify any significant intragroup differences. Design Retrospective cross-sectional analysis of records of patients (n = 512) held on a computerized database with a chronological age between 3 and 11 years resident in the UK/Republic of Ireland and with a formal diagnosis of autism, Asperger syndrome (AS) or autism spectrum disorder (ASD). Methods Non-parametric analysis (P > 0.01) of the frequency of specific variables for PDD subgroups reported by parents/primary caregiver. Variables included timing of symptom onset, presence of skills acquired prior to symptom onset, indications of regression and regression events, current language, history of viral infections, history of ear problems, achievement of continence, current skin complaints, current bowel habits and adverse events at parturition. Results Preliminary results showed general agreement with the principle diagnostic differences between the PDD subgroups with patients diagnosed with AS showing an increased frequency of skills acquired before symptom onset (two- to three-word phrase speech, toileting skills) and a decreased frequency of regression in acquired skills when compared with other PDD subgroups. Developmental milestones such as the achievement of bowel and bladder continence were also more frequently reported for the AS group. Infantile feeding problems defined as vomiting, reflux, colic and failure to feed were more frequently reported for the AS group as was a reported history of the bacterial skin infection impetigo. Results are discussed with reference to relationships between behavioural and somatic factors in PDD. [source] Factors of significance for mobility in children with myelomeningoceleACTA PAEDIATRICA, Issue 2 2003S Norrlin Aim: To investigate neurological impairment, hand function and cognitive function in a group of children with myelomeningocele, in order to identify factors of significance for independent mobility and the physical assistance required for mobility in daily activities. Methods: The study material comprised 32 children, aged 6,11 y and without mental retardation. Mobility was assessed with the Pediatric Evaluation of Disability Inventory, scored as caregiver assistance. Statistical differences and correlations between the caregiver assistance scores and the selected variables were analysed. Results: Nine children scored independent mobility. The independent children had better hand coordination (p= 0.004) and walking ability (p= 0.01), lower cele levels (p= 0.011), higher performance IQ (p= 0.027), better visuospatial function (p= 0.029) and executive function (p= 0.037) than the others. The caregiver assistance scores were lower for both the children with early and severe symptoms of brainstem dysfunction and the children with scoliosis. Statistically significant correlations were found between the need for caregiver assistance and reduced walking ability, high cele level, poor hand strength and coordination, visuospatial function, executive function and performance IQ. In the subgroup of children who needed a wheelchair or walking aids, hand strength was the only variable significantly correlated with caregiver assistance (rs= 0.703, p= 0.000). Conclusion: Most of the children were dependent on others in daily activities. Impaired hand function and cognitive function were significant for mobility, and this has implications for the therapy programme in children with myelomeningocele. [source] Factors modifying stress from adverse effects of immunosuppressive medication in kidney transplant recipientsCLINICAL TRANSPLANTATION, Issue 1 2005Jaroslav Rosenberger Abstract:, Introduction:, The adverse effects of immunosuppression appear in the majority of patients with a negative impact on morbidity, mortality and quality of life. The group of adverse symptoms manifested as changes in appearance, mood and energy are often more stressful than serious metabolic changes because of their direct negative influence on patients' well-being. The aim of this study is to explore the adverse symptoms of immunosuppressive medication which are the most stressful for transplanted patients, and which are the modifying factors. Patients and methods:, A total of 157 adult kidney transplant recipients from two transplant centres in Slovakia with a functioning graft transplanted <7 yr ago were examined. Patients participated in an interview focusing on stress from adverse effects, and their education and social support. Medical records were searched for information about immunosuppression protocols, dialysis treatment before transplantation, type of received organ and period after transplantation. The effect of the selected variables on the total score for stress from adverse effects was tested using ANOVA. The effect of the selected factors on stress from each single adverse effect was explored using t -test and ANOVA. Results:, The most stressful symptoms were pain, weakness, weight gain, facial changes, depression and anxiety. The mean value of the total score for stress from adverse effects was 8.03 ± 6.53 (minimum 0, maximum 30, range: 0,64), indicating low stress. Women and patients with lower education significantly more often felt the adverse effects of immunosuppression as stressful (p < 0.001 and p < 0.05, respectively). Age, social support, dialysis modality before transplantation, time from transplantation and type of immunosuppressive treatment did not affect the total score for stress from adverse effects. However, variables that were not significant in the overall score reached significance in some symptoms. Conclusions:, Women and patients with lower education significantly more often felt the adverse effects of immunosuppression as stressful; in a more detailed analysis the use of new drugs was connected with less stress in some symptoms. The use of these drugs can improve life quality for transplant recipients, decrease non-compliance, and thus prevent graft loss. [source] | |||||||||||||