New Sample (new + sample)

Distribution by Scientific Domains

Selected Abstracts

A multivariate logistic regression equation to screen for dysglycaemia: development and validation

B. P. Tabaei
Abstract Aims To develop and validate an empirical equation to screen for dysglycaemia [impaired fasting glucose (IFG), impaired glucose tolerance (IGT) and undiagnosed diabetes]. Methods A predictive equation was developed using multiple logistic regression analysis and data collected from 1032 Egyptian subjects with no history of diabetes. The equation incorporated age, sex, body mass index (BMI), post-prandial time (self-reported number of hours since last food or drink other than water), systolic blood pressure, high-density lipoprotein (HDL) cholesterol and random capillary plasma glucose as independent covariates for prediction of dysglycaemia based on fasting plasma glucose (FPG) , 6.1 mmol/l and/or plasma glucose 2 h after a 75-g oral glucose load (2-h PG) , 7.8 mmol/l. The equation was validated using a cross-validation procedure. Its performance was also compared with static plasma glucose cut-points for dysglycaemia screening. Results The predictive equation was calculated with the following logistic regression parameters: P = 1 + 1/(1 + e,X) = where X = ,8.3390 + 0.0214 (age in years) + 0.6764 (if female) + 0.0335 (BMI in kg/m2) + 0.0934 (post-prandial time in hours) + 0.0141 (systolic blood pressure in mmHg) , 0.0110 (HDL in mmol/l) + 0.0243 (random capillary plasma glucose in mmol/l). The cut-point for the prediction of dysglycaemia was defined as a probability , 0.38. The equation's sensitivity was 55%, specificity 90% and positive predictive value (PPV) 65%. When applied to a new sample, the equation's sensitivity was 53%, specificity 89% and PPV 63%. Conclusions This multivariate logistic equation improves on currently recommended methods of screening for dysglycaemia and can be easily implemented in a clinical setting using readily available clinical and non-fasting laboratory data and an inexpensive hand-held programmable calculator. [source]

Sampling Procedures for Coordinating Stratified Samples: Methods Based on Microstrata

Desislava Nedyalkova
Summary The aim of sampling coordination is to maximize or minimize the overlap between several samples drawn successively in a population that changes over time. Therefore, the selection of a new sample will depend on the samples previously drawn. In order to obtain a larger (or smaller) overlap of the samples than the one obtained by independent selection of samples, a dependence between the samples must be introduced. This dependence will emphasize (or limit) the number of common units in the selected samples. Several methods for coordinating stratified samples, such as the Kish & Scott method, the Cotton & Hesse method, and the Rivière method, have already been developed. Using simulations, we compare the optimality of these methods and their quality of coordination. We present six new methods based on permanent random numbers (PRNs) and microstrata. These new methods have the advantage of allowing us to choose between positive or negative coordination with each of the previous samples. Simulations are run to test the validity of each of them. Résumé Le but de la coordination d'échantillons est de maximiser ou minimiser le recouvrement de plusieurs échantillons à l'intérieur d'une population qui évolue au fil des temps. Pour effectuer une coordination, la sélection d'un nouvel échantillon dépendra donc des échantillons précédemment tirés. Afin d'obtenir un recouvrement plus fort ou plus faible que celui fourni par des tirages indépendants, une dépendance entre les échantillons doit être introduite. Cette dépendance va augmenter ou limiter le nombre d'unités communes à tous les échantillons sélectionnés. Plusieurs méthodes pour coordonner des échantillons stratifiés ont déjàété développées. Parmi eux les méthodes de Kish and Scott, de Cotton and Hesse, et de Rivière sont présentées en détail. En utilisant des simulations, on compare l'optimalité et la qualité de la coordination pour chacune de ces trois méthodes. On présente six nouvelles méthodes basées sur l'utilisation de nombres aléatoires permanents et des microstrates et on essaye de les valider à l'aide des simulations. [source]

Effects of Accountability on Rating Behavior and Rater Accuracy

Neal P. Mero
We tested whether improvements in rater accuracy on a performance-appraisal task attributed to rater accountability could be explained by variance in rater behavior. Data from Mero and Motowidlo (1995) were used initially to test whether observed improvements in rater accuracy could be explained by rating process behaviors of attending to relevant subordinate performance and taking better notes to record that performance. Results showed that both behaviors were correlated with accuracy and that these behaviors partially mediated the relationship between accountability and improved decision quality for participants who were held accountable for their rating decision and did not have any preconceived information about that rating from their supervisor. We then tested this process model on a new sample of participants and found that attentiveness and notetaking mediated the relationship between accountability and accuracy. [source]

Psychiatric disorders and family functioning in children and adolescents with functional abdominal pain syndrome

Ahmad Ghanizadeh
Abstract Background and Aim:, Functional abdominal pain syndrome (FAPS) is a functional gastrointestinal disorder. There is a heightened risk when conducting potentially dangerous and unnecessary medical investigations and procedures in children with FAPS. The aim of this study was to survey the rate of the psychiatric disorders and family functioning in children and adolescents with FAPS. Methods:, The subjects were a consecutive new sample of 45 children and adolescents with FAPS, 45 with an organic abdominal pain, and 45 pain-free comparison subjects aged 5,18 years that were interviewed using the Farsi version of K-SADS. Family functioning and the severity of pain were also studied. Results:, About 51.1% of patients with FAPS suffered from at least one psychiatric disorder. Psychiatric disorders in the FAPS patients studied included general anxiety disorder (8.9%), obsessive-compulsive disorder (11.1%), attention deficit hyperactivity disorder (15.6%), separation anxiety disorder (24.4%), and major depressive disorder (15.6%). Except for generalized anxiety disorder and tic disorder, the other disorders were significantly more common in the FAPS group than in the two other control groups. Family functioning scores were not significantly different between groups. Discussion:, There is a high rate of psychiatric disorders in children and adolescents with FAPS in Iran, but our study found fewer incidences of disorders than previous reports have indicated. Family dysfunction difficulties in FAPS children are not more common than those in the control groups. [source]

Is the placebo powerless?

Update of a systematic review with 52 new randomized trials comparing placebo with no treatment
Abstract. Background., It is widely believed that placebo interventions induce powerful effects. We could not confirm this in a systematic review of 114 randomized trials that compared placebo-treated with untreated patients. Aim., To study whether a new sample of trials would reproduce our earlier findings, and to update the review. Methods., Systematic review of trials that were published since our last search (or not previously identified), and of all available trials. Results., Data was available in 42 out of 52 new trials (3212 patients). The results were similar to our previous findings. The updated review summarizes data from 156 trials (11 737 patients). We found no statistically significant pooled effect in 38 trials with binary outcomes, relative risk 0.95 (95% confidence interval 0.89,1.01). The effect on continuous outcomes decreased with increasing sample size, and there was considerable variation in effect also between large trials; the effect estimates should therefore be interpreted cautiously. If this bias is disregarded, the pooled standardized mean difference in 118 trials with continuous outcomes was ,0.24 (,0.31 to ,0.17). For trials with patient-reported outcomes the effect was ,0.30 (,0.38 to ,0.21), but only ,0.10 (,0.20 to 0.01) for trials with observer-reported outcomes. Of 10 clinical conditions investigated in three trials or more, placebo had a statistically significant pooled effect only on pain or phobia on continuous scales. Conclusion., We found no evidence of a generally large effect of placebo interventions. A possible small effect on patient-reported continuous outcomes, especially pain, could not be clearly distinguished from bias. [source]

Measuring Parental Perceptions of Child Oral Health-related Quality of Life

Aleksandra Jokovic MSc
Abstract Objectives: The aim of this study was to develop and evaluate the P-CPQ, a measure of parental/caregiver perceptions of the oral health-related quality of life of children. This forms one component of the Child Oral Health Quality of Life Questionnaire (COHQOL). Methods: An item pool was developed through a review of existing child health questionnaires and interviews with parents/caregivers of children with pedodontic, orthodontic, and orofacial conditions. The resulting 47 items were used in a study in which 208 parents/caregivers provided data on their frequency and importance. The 31 items rated the most frequent and important were selected for the final questionnaire (P-CPQ). The P-CPQ validity and reliability were assessed by a new sample of 231 parents, 79 of whom completed two copies for the assessment of test-retest reliability. Results: The P-CPQ discriminated among the three clinical groups included in the expected direction. Within-group analyses using clinical data provided some evidence that scores were associated with the severity of the condition. The P-CPQ also showed good construct validity. It had excellent internal consistency reliability with a Cronbach's alpha of 0.94 and demonstrated perfect test-retest reliability (ICC=0.85). Conclusion: The study provides data to indicate that the P-CPQ is valid and reliable. [source]

Cytonuclear disequilibrium in a hybrid zone involving deep-sea hydrothermal vent mussels of the genus Bathymodiolus

Y. Won
Abstract A hybrid zone involving the deep-sea mussels, Bathymodiolus azoricus and B. puteoserpentis, was recently discovered at Broken Spur hydrothermal vent field (29°10, N, 43°10, W) along an intermediate segment of the Mid-Atlantic Ridge axis. Examination of nuclear (allozymes) and cytoplasmic (mitochondrial DNA) gene markers in a new sample from Broken Spur revealed significant cytonuclear disequilibrium caused by an excess of the parental types (coupling phase) and a deficiency of recombinants (repulsion phase). An assignment test of individual multilocus genotypes also revealed an excess of parental genotypes in the admixed population. These results support the hypothesis that the Broken Spur mussel population comprises a nonequilibrium mixture of parental immigrants and hybrid individuals. [source]

A new sample of broad absorption-line quasars exhibiting the ghost of Lyman ,

Matthew North
ABSTRACT We have searched the broad absorption-line quasar (BAL QSO) sample presented recently by Reichard et al. for objects exhibiting the so-called ,ghost of Lyman ,'. This ghost manifests as a hump near ,5900 km s,1 in the troughs of the broad absorption lines and provides strong evidence for the importance of line driving in powering the outflows from BAL QSOs. Of the 224 sample BAL QSOs selected from the Sloan Digital Sky Survey Early Data Release, 198 satisfy our redshift constraints and 58 show clear evidence of multiple-trough (MT) structure in the C iv 1550 Å line. A composite spectrum constructed from this MT sample already shows evidence for a ghost feature. Narrowing our classification scheme further, we define a set of 36 objects that individually show evidence of a ghost feature, and then apply further cuts to arrive at a final ,best sample' that contains our seven strongest ghost candidates. A further five objects show evidence for a ghost feature that is almost strong enough to merit inclusion in our best sample. Despite its limited size, our best sample more than doubles the number of known BAL QSOs with clear ghost signatures and should make an excellent basis for detailed follow-up studies. [source]

Natural variation in baseline data: when do we call a new sample ,resistant'?,

Lukas Schaub
Abstract Mortality of pear psylla to amitraz was studied by means of bioassays. Variation between samples, temporal variation within the season in one orchard and spatial variation between Swiss regions were considered. Variation between samples was large enough to produce different Probit functions and LC50 values. Temporal and spatial variations were too small to indicate resistance. Prediction intervals of the pooled functions using bootstrapping were calculated to determine if future samples come from a population with decreased sensitivity. Probabilistic criteria on the population level were proposed for resistance. © 2002 Society of Chemical Industry [source]

Existence of a genetic risk factor on chromosome 5q in Italian Coeliac Disease families

Coeliac disease (CD) is a malabsorptive disorder of the small intestine resulting from ingestion of gluten. The HLA risk factors involved in CD are well known but do not explain the whole genetic susceptibility. Several regions of potential linkage on chromosomes 3q, 5q, 10q, 11q, 15q and 19q have already been reported in the literature. These six regions were analyzed with the Maximum Lod Score method on a dense set of markers. A new sample of 89 Italian sibpairs was available for study. There was no evidence for linkage for any of the regions tested, except for chromosome 5q. For this region, our data, as well as a sample of 93 sibpairs from our first genome screen (Greco et al. 1998), are compatible with the presence of a risk factor for CD with a moderate effect. [source]

Association of the G-2548A polymorphism in the 5, region of the LEP gene with overweight

Mutations in the translated part of the leptin gene (LEP) have been found in only two families. Nevertheless DNA polymorphisms in the LEP region are linked to extreme obesity. We previously found in the 5, region of LEP a polymorphism, G-2548A, associated with a difference in BMI reduction following a low calorie diet in overweight women. Recently, this polymorphism was associated with extreme obesity in women. In this work, we genotyped a new sample from the general population including 314 normal weight (BMI < 27 kg/m2) and 109 overweight subjects (BMI , 27 kg/m2). The genotype and allele frequencies were significantly different between groups, with the G-2548 allele being more frequent in the overweight subjects (p < 0.01). In men, carriers of this allele had lower leptin concentrations adjusted for fat mass (p= 0.05). Our results indicate that variations at the leptin locus are associated with common obesity phenotypes, and not only with extreme obesity or the rare mendelian obesity syndromes. [source]

A sample of GHz-peaked spectrum sources selected at RATAN-600: Spectral and variability properties

K.V. Sokolovsky
Abstract We describe a new sample of 226 GPS (GHz-Peaked Spectrum) source candidates selected using simultaneous 1,22 GHz multi-frequency observations with the RATAN-600 radio telescope. Sixty objects in our sample are identified as GPS source candidates for the first time. The candidates were selected on the basis of their broad-band radio spectra only We. discuss the spectral and variability properties of selected objects of different optical classes (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

A survey of Low Luminosity Compact sources

M. Kunert-Bajraszewska
Abstract Based on the FIRST and SDSS catalogues a flux density limited sample of weak Compact Steep Spectrum (CSS) sources with radio luminosity below 1026WHz,1 at 1.4 GHz has been constructed. Our previous multifrequency observations of CSS sources have shown that low luminosity small-scale objects can be strong candidates for compact faders. This finding supports the idea that some small-size radio sources are short-lived phenomena because of a lack of significant fuelling. They never ,grow up' to become FRI or FRII objects. This new sample marks the start of a systematic study of the radio properties and morphologies of the population of low luminosity compact (LLC) objects. An investigation of this new sample should also lead to a better understanding of compact faders. In this paper, the results of the first stage of the new project , the L-band MERLIN observations of 44 low luminosity CSS sources are presented (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Chromate reduction in wastewater at different pH levels using thin iron wires,A laboratory study

Li-Yang Chang
Abstract The effectiveness of using thin zero-valent iron (Fe0) wires in the treatment of wastewater generated from a metal cleaning facility and with a pH in the range of 2 to 10 was examined. It was found that (1) when the sample containing low levels of total chromium (,14 mg/L) was mixed with iron wires at a pH of 3 to 8, 50 to 90% of the total chromium could be reduced in 4 h; (2) the initial reduction efficiency was pH-dependent: the lower the pH, the higher the reduction rate; (3) variations of solution pH, redox electrical potential, and electrical conductivity (EC) in samples were also pH-dependent; (4) the adsorption/reduction efficiency was limited by the diffusion of Cr(VI) from wastewater to the iron surface when the test duration was long; (5) when the initial pH = 3, iron corrosion and redox reaction dominated the reduction process; however, with pH = 8 or 10, corrosion, surface passivation, or metal precipitation could compete with reduction; (6) the used iron wires were still effective in chromium removal in new samples at pH = 3; and (7) some desorption of adsorbed chromium was observed in acidic samples when the test duration was long. Scanning electron microscope images and energy-dispersive X-ray spectra collected from iron samples also indicate that the efficiency of chromium adsorption/reduction is pH-dependent. Our results suggest that using zero-valent iron to polish acidic wastewater containing low contents of chromium and other heavy metals is feasible. © 2005 American Institute of Chemical Engineers Environ Prog, 2005 [source]

Do patients with psychogenic nonepileptic seizures produce trustworthy findings on neuropsychological tests?

EPILEPSIA, Issue 4 2008
Carl B. Dodrill
Summary Drane et al. (2006) has recently raised the possibility that patients with psychogenic nonepileptic seizures (PNES) may make poor effort in taking neuropsychological tests in comparison with patients with epilepsy (ES). Therefore, findings previously reported with PNES patients may be in error, especially with regard to tests of mental abilities. Using the same measure of effort used by Drane et al. (2006) but with more broadly selected patients, this paper attempts to replicate their findings with new samples of ES (n = 65) and PNES (n = 32) cases. However, their findings could not be replicated, and no differences in test taking effort could be demonstrated across the groups. The highly selected samples of Drane et al. (2006) appear to be responsible for their results, and neuropsychological findings with PNES patients appear to be as trustworthy as those with ES patients. [source]


EVOLUTION, Issue 1 2002
Cortland K. Griswold
Abstract We analyzed sequences from a 275-bp hypervariable region in the 5, end of the mitochondrial DNA control region in 190 common chaffinches (Fringilla coelebs) from 19 populations in Europe and North Africa, including new samples from Greece and Morocco. Coalescent techniques were applied to estimate the time to the most recent common ancestor (TMRCA) and divergence times of these populations. The first objective of this study was to infer the locations of refugia where chaffinches survived the last glacial episode, and this was achieved by estimating the TMRCA of populations in regions surrounding the Mediterranean that were unglaciated in the late Pleistocene. Although extant populations in Iberia, Corsica, Greece, and North Africa harbor haplotypes that are basal in a phylogenetic tree, this information alone cannot be used to infer that these localities served as refugia, because it is impossible to infer the ages of populations and their divergence times without also considering the population genetic processes of mutation, migration, and drift. Provided we assume the TMRCAs of populations are a reasonable estimate of a population's age, coalescent-based methods place resident populations in Iberia, Corsica, Greece, and North Africa during the time of the last glacial maximum, suggesting these regions served as refugia for the common chaffinch. The second objective was to determine when populations began diverging from each other and to use this as a baseline to estimate current levels of gene flow. Divergence time estimates suggest that European populations began diverging about 60,000 years before present. The relatively recent divergence of populations in North Africa, Italy, and Iberia may explain why classic migration estimates based on equilibrium assumptions are high for these populations. We compare these estimates with nonequilibrium-based estimates and show that the nonequilibrium estimates are consistently lower than the equilibrium estimates. [source]

Imputation aware meta-analysis of genome-wide association studies

Noah Zaitlen
Abstract Genome-wide association studies have recently identified many new loci associated with human complex diseases. These newly discovered variants typically have weak effects requiring studies with large numbers of individuals to achieve the statistical power necessary to identify them. Likely, there exist even more associated variants, which remain to be found if even larger association studies can be assembled. Meta-analysis provides a straightforward means of increasing study sample sizes without collecting new samples by combining existing data sets. One obstacle to combining studies is that they are often performed on platforms with different marker sets. Current studies overcome this issue by imputing genotypes missing from each of the studies and then performing standard meta-analysis techniques. We show that this approach may result in a loss of power since errors in imputation are not accounted for. We present a new method for performing meta-analysis over imputed single nucleotide polymorphisms, show that it is optimal with respect to power, and discuss practical implementation issues. Through simulation experiments, we show that our imputation aware meta-analysis approach outperforms or matches standard meta-analysis approaches. Genet. Epidemiol. 34: 537,542, 2010. © 2010 Wiley-Liss, Inc. [source]

Comparing Personality Scales Across Time: An Illustrative Study of Validity and Consistency in Life-Span Archival Data

Leslie R. Martin
The goals of this study were: (a) to examine whether personality scales, meaningful in contemporary terms, could be derived from archival data; and (b) to use these scales to aid our understanding of the relation of personality to mortality. NEO PI-R data and a battery of archival items, taken from Terman's Life Cycle Study, were collected on two new samples (sample 1 mean age = 11.9, n = 167; sample 2 mean age = 22.2, n = 203). Measurement invariance of the archival scales was assessed, and validity was examined using both rational analyses and associations with the Five Factor Model. It was demonstrated that interpretable scales can be derived from 50- to 70-year-old archival data. The archival adult personality data were then used to predict mortality. Conscientiousness remains the strongest personality predictor of longevity. Criteria for establishing the validity of archivally derived scales are suggested. [source]

Spectroscopy of globular cluster candidates in the Sculptor group galaxies NGC 253 and 55

M. A. Beasley
We have obtained spectra for 103 published globular cluster candidates in the Sculptor group galaxies NGC 253 and 55. On the basis of radial velocities and digitized plate images, 14 globular clusters are identified in NGC 253 and one probable globular cluster is identified in NGC 55. The majority of the objects in the sample appear to be background galaxies. We have obtained and analysed COSMOS plate scans of NGC 253 and 55 and use these along with the spectroscopically identified clusters to define new samples of globular cluster candidates in the two galaxies which should have reduced contamination. [source]