bluuebunny/crossref_metadata_2025_split huggingface dataset:
Impact of Multiple Matched Controls on Design Sensitivity in Observational Studies
Authors: Rosenbaum Paul R. 
Published: February 2013

SummaryIn an observational study, one treated subject may be matched for observed covariates to either one or several untreated controls. The common motivation for using several controls rather than one is to increase the power of a test of no effect under the doubtful assumption that matching for observed covariates suffices to remove bias from nonrandom treatment assignment. Does the choice between one or several matched controls affect the sensitivity of conclusions to violations of this doubtful assumption? With continuous responses, it is known that reducing the heterogeneity of matched pair differences reduces sensitivity to unmeasured biases, but increasing the sample size has a highly circumscribed effect on sensitivity to bias. Is the use of several controls rather than one analogous to a reduction in heterogeneity or to an increase in sample size? The issue is examined for Huber'sm‐statistics, including thet‐test, the examination having three components: an example, asymptotic calculations using design sensitivity, and a simulation. Use of multiple controls with continuous responses yields a nontrivial reduction in sensitivity to unmeasured biases. An example looks at lead and cadmium in the blood of smokers from the 2008 National Health and Nutrition Examination Survey. A by‐product of the discussion is a new result giving the design sensitivity for the permutation distribution ofm‐statistics.
Prevalence Projections of Chronic Diseases and Impact of Public Health Intervention
Authors: Joly Pierre , Touraine Célia , Georget Aurore , Dartigues Jean‐François , Commenges Daniel , Jacqmin‐Gadda Hélène 
Published: February 2013

SummaryThe estimation of future prevalences of chronic diseases is essential for public health policy. Using incidence estimates from cohort data and demographic projections for general mortality and population sizes, we propose a method based on a general illness–death model to make prevalence projections for chronic diseases. In contrast to previously published methods, we account for differences between global mortality and mortality of healthy subjects and compare two assumptions regarding the secular trend for mortality of diseased subjects. Then we develop a methodology to estimate changes in future disease prevalences resulting from prevention campaign to reduce the frequency or the excess risk associated with a risk factor. The methods are applied for estimating dementia prevalence in France between 2010 and 2030.
Relational approach to work: conceptual definition and scale development
Authors: Matthew Cynthia T. , Buontempo Gina , Block Caryn J. 
Published: February 2013

AbstractThe aim of this study is to conceptually define and develop a scale to measure relational behavior in the workplace associated with theorized differences in how women and men approach work. Drawing from the gender studies and organizational literatures, the construct is defined and a relational approach to work scale is developed. Data were collected from a sample of 223 graduate students with work experience. Findings show preliminary evidence of reliability and validity.
The combined effect of ratee's bodyweight and past performance information on performance judgments
Authors: Nieminen Levi R. G. , Rudolph Cort W. , Baltes Boris B. , Casper Christine M. , Wynne Kevin T. , Kirby Lyndsay C. 
Published: February 2013

AbstractFew studies have examined how various biases operate in combination to influence performance judgments. Along these lines, the current study used experimental methods to test four competing models of the combined influence of ratee's bodyweight and past performance information on performance judgments. Results were consistent with an additive model, such that ratee's bodyweight and information about ratee's past performance combined independently to affect performance judgments. Consistent with a double disadvantage effect, the least favorable performance judgments were made for an overweight ratee with poor previous performance. Finally, mixed evidence was obtained for the interaction of ratee's bodyweight and perceptions of ratee's physical attractiveness, such that high‐perceived attractiveness buffered against the otherwise negative performance ratings associated with overweight status.
Attitude toward environmental policy measures related to value orientation
Authors: Hansla André , Gärling Tommy , Biel Anders 
Published: February 2013

AbstractModerated mediation effects on attitude toward environmental policy measures of a self‐enhancement vs. self‐transcendence value orientation were examined in two studies. Study 1 (n = 91) showed that for policy measures incurring nontransparent personal costs, influence of value orientation on attitude is fully mediated by environmental concern, whereas for measures incurring transparent personal costs, influence is partially mediated by environmental concern. Study 2 (n = 71) showed that while influence of value orientation on attitude toward eco‐labeled electricity is not mediated by environmental concern, it is fully mediated by reluctance to pay surcharges for eco‐labeled electricity. Value orientation was also shown to moderate influence of reluctance to pay on attitude in that reluctance had an effect only for a self‐enhancement value orientation.
Efficacy of different mouthrinse formulations in reducing oral malodour: a randomized clinical trial
Authors: Dadamio Jesica , Van Tournout Marie , Teughels Wim , Dekeyser Christel , Coucke Wim , Quirynen Marc 
Published: February 2013

AbstractAimsThe aim of this study was to assess the efficacy of mouthrinses formulations in oral malodour.Material & MethodsThis single‐centre, double‐blind, randomized, parallel group clinical trial compared the efficacy of Halita™ and meridol® with and without zinc lactate versus negative and positive control. Volunteers with confirmed oral malodour (18/group) rinsed with one mouthrinse during 7 days (15 ml, 2x/day for 1 min.). 15 min. after a first rinse (masking effect), and after 7 days (therapeutic effect) the change in organoleptic scores and level of sulphur compounds was recorded.ResultsAll rinses showed a masking effect (OLS 1 to 2 values reduced), only the rinses with antimicrobial ingredients showed a therapeutic effect (OLS 1 to 1.5 value less). The addition of zinc resulted in a more pronounced masking effect. Halita™ and meridol® with zinc showed the best therapeutic effect.ConclusionAlthough the masking effect of the rinses can be attributed partially to a dilution and the effect of aromas, the therapeutic effect should be linked to the anti‐microbial action of active ingredients and counter action of zinc ions on VSC. A complete resolution of the unpleasant breath by additional mechanical intervention remains to be proven.
Care Experiences of Managed Care Medicare Enrollees Near the End of Life
Authors: Elliott Marc N. , Haviland Amelia M. , Cleary Paul D. , Zaslavsky Alan M. , Farley Donna O. , Klein David J. , Edwards Carol A. , Beckett Megan K. , Orr Nate , Saliba Debra 
Published: February 2013

ObjectivesTo compare reports about care experiences of individuals who died within 1 year of survey with reports of those who did not.DesignMedicare Advantage (MA) Consumer Assessment of Healthcare Providers and Systems (CAHPS) surveys asked about care experiences. Survey completion dates were linked to Social Security Administration death records to identify enrollees dying within 1 year of survey completion. Propensity‐score weighting combined with regression‐based case‐mix adjustment was used to compare these individuals’ experiences with experiences of those who were alive 1 year later.SettingNationally representative sample of MA enrollees.ParticipantsFour hundred two thousand five hundred ninety‐three MA enrollees responding to 2008 and 2009 CAHPS Surveys.MeasurementsOutcomes were five care ratings (plan, prescription drug coverage, doctor, specialists, care) and five composite measures of care (getting needed care, getting care quickly, doctor communication, getting drugs, getting drug information). Analyses were adjusted for age, sex, race and ethnicity, education, Medicaid status, geographic region, and several health status measures.ResultsTwelve thousand one hundred two enrollees (3%) died within 1 year of survey completion (near‐end‐of‐life group). Those enrollees reported slightly better experiences than other enrollees with respect to getting care quickly (+2%, P < .001) and gave slightly higher ratings for their plans (+1%, P = .02) and prescription drug coverage (+1%, P < .001). There were no measures of participant experience for which the near‐end‐of‐life group reported worse experiences than other enrollees.ConclusionContrary to analyses based on retrospective reports from surviving relatives after an individual's death, MA enrollees’ reports about care within 1 year of death were as good as or better than reports of other MA enrollees. Future research might investigate whether results are similar in other Medicare populations.
Using a Choice Design to Screen Nutraceutical‐Rich Juices
Authors: Lawless Lydia J.R. , Threlfall Renee T. , Meullenet Jean‐François 
Published: February 2013

AbstractAvailability of functional foods containing nutraceutical compounds has increased because of growing demands for health‐oriented products. Choice surveys, which present hypothetical choice sets to participants, can be used to assess the market potential for products like nutraceutical‐rich juices. An online choice survey (n = 1,035) was used to identify a preferred juice blend and factors that influenced choice for juice blends of açaí, black cherry, blueberry, Concord grape, cranberry and/or pomegranate juice. Participants were given potential health‐oriented information (ranking of antioxidant composites) during the survey. Participants indicated perceived overall liking of individual juices and answered attitudinal statements for time preference and antioxidant information. Concord grape juice was the most liked, followed by cranberry, pomegranate, black cherry, blueberry and açaí. Liking of juice was positively correlated to presence of Concord grape and cranberry juice. Unfamiliarity of juices was negatively correlated to liking of juices. Analysis indicated that black cherry, Concord grape and pomegranate juice blend had the highest marginal utility as well as high overall liking and high antioxidant levels. Choice surveys can be used as screening designs for product development to determine the ingredients that drive consumer choices for nutraceutical‐rich products.Practical ApplicationsScreening designs are necessary to maximize research resource potential and to select the most suitable products for further development. Screening designs can be used for other products to facilitate the selection of the best profiles.
Landscape genetics of an early successional specialist in a disturbance‐prone environment
Authors: Pereoglou F. , Lindenmayer D. B. , MacGregor C. , Ford F. , Wood J. , Banks S. C. 
Published: February 2013

AbstractSpecies that specialize in disturbed habitats may have considerably different dispersal strategies than those adapted to more stable environments. However, little is known of the dispersal patterns and population structure of such species. This information is important for conservation because many postfire specialists are at risk from anthropogenic changes to natural disturbance regimes. We used microsatellite markers to assess the effect of landscape variation and recent disturbance history on dispersal by a small mammal species that occupies the early seral stage of vegetation regeneration in burnt environments. We predicted that a postfire specialist would be able to disperse over multiple habitat types (generalist) and not exhibit sex‐biased dispersal, as such strategies should enable effective colonization of spatially and temporally variable habitat. We found significant differentiation between sites that fitted an isolation‐by‐distance pattern and spatial autocorrelation of multilocus genotypes to a distance of 2–3 km. There was no consistent genetic evidence for sex‐biased dispersal. We tested the influence of different habitat‐ and fire‐specific landscape resistance scenarios on genetic distance between individuals and found a significant effect of fire. Our genetic data supported recently burned vegetation having greater conductance for gene flow than unburnt habitat, but variation in habitat quality between vegetation types and occupied patches had no effect on gene flow. Postfire specialists must evolve an effective dispersal ability to move over distances that would ensure access to early successional stage vegetation. Natural disturbance and natural heterogeneity may therefore not influence population genetic structure as negatively as expected.
Genetic diversity and differentiation in a wide ranging anadromous fish, American shad (Alosa sapidissima), is correlated with latitude
Authors: Hasselman Daniel J. , Ricard Daniel , Bentzen Paul 
Published: February 2013

AbstractStudies that span entire species ranges can provide insight into the relative roles of historical contingency and contemporary factors that influence population structure and can reveal patterns of genetic variation that might otherwise go undetected. American shad is a wide ranging anadromous clupeid fish that exhibits variation in demographic histories and reproductive strategies (both semelparity and iteroparity) and provides a unique perspective on the evolutionary processes that govern the genetic architecture of anadromous fishes. Using 13 microsatellite loci, we examined the magnitude and spatial distribution of genetic variation among 33 populations across the species' range to (i) determine whether signals of historical demography persist among contemporary populations and (ii) assess the effect of different reproductive strategies on population structure. Patterns of genetic diversity and differentiation among populations varied widely and reflect the differential influences of historical demography, microevolutionary processes and anthropogenic factors across the species' range. Sequential reductions of diversity with latitude among formerly glaciated rivers are consistent with stepwise postglacial colonization and successive population founder events. Weak differentiation among U.S. iteroparous populations may be a consequence of human‐mediated gene flow, while weak differentiation among semelparous populations probably reflects natural gene flow. Evidence for an effect of reproductive strategy on population structure suggests an important role for environmental variation and suggests that the factors that are responsible for shaping American shad life history patterns may also influence population genetic structure.
Uncovering symbiont‐driven genetic diversity across North American pea aphids
Authors: Russell Jacob A. , Weldon Stephanie , Smith Andrew H. , Kim Kyungsun L. , Hu Yi , Łukasik Piotr , Doll Steven , Anastopoulos Ioannis , Novin Matthew , Oliver Kerry M. 
Published: February 2013

AbstractHeritable genetic variation is required for evolution, and while typically encoded within nuclear and organellar genomes, several groups of invertebrates harbour heritable microbes serving as additional sources of genetic variation. Hailing from the symbiont‐rich insect order Hemiptera, pea aphids (Acyrthosiphon pisum) possess several heritable symbionts with roles in host plant utilization, thermotolerance and protection against natural enemies. As pea aphids vary in the numbers and types of harboured symbionts, these bacteria provide heritable and functionally important variation within field populations. In this study, we quantified the cytoplasmically inherited genetic variation contributed by symbionts within North American pea aphids. Through the use of Denaturing Gradient Gel Electrophoresis (DGGE) and 454 amplicon pyrosequencing of 16S rRNA genes, we explored the diversity of bacteria harboured by pea aphids from five populations, spanning three locations and three host plants. We also characterized strain variation by analysing 16S rRNA, housekeeping and symbiont‐associated bacteriophage genes. Our results identified eight species of facultative symbionts, which often varied in frequency between locations and host plants. We detected 28 cytoplasmic genotypes across 318 surveyed aphids, considering only the various combinations of secondary symbiont species infecting single hosts. Yet the detection of multiple Regiella insecticola, Hamiltonella defensa and Rickettsia strains, and diverse bacteriophage genotypes from H. defensa, suggest even greater diversity. Combined, these findings reveal that heritable bacteria contribute substantially to genetic variation in A. pisum. Given the costs and benefits of these symbionts, it is likely that fluctuating selective forces play a role in the maintenance of this diversity.
Mating system evolution and worker caste diversity inPheidoleants
Authors: Huang Ming H. , Wheeler Diana E. , Fjerdingstad Else J. 
Published: February 2013

AbstractThe efficiency of social groups is generally optimized by a division of labour, achieved through behavioural or morphological diversity of members. In social insects, colonies may increase the morphological diversity of workers by recruiting standing genetic variance for size and shape via multiply mated queens (polyandry) or multiple‐breeding queens (polygyny). However, greater worker diversity in multi‐lineage species may also have evolved due to mutual worker policing if there is worker reproduction. Such policing reduces the pressure on workers to maintain reproductive morphologies, allowing the evolution of greater developmental plasticity and the maintenance of more genetic variance for worker size and shape in populations.Pheidoleants vary greatly in the diversity of worker castes. Also, their workers lack ovaries and are thus invariably sterile regardless of the queen mating frequency and numbers of queens per colony. This allowed us to perform an across‐species study examining the genetic effects of recruiting more patrilines on the developmental diversity of workers in the absence of confounding effects from worker policing. Using highly variable microsatellite markers, we found that the effective mating frequency of the soldier‐polymorphicP. rhea(avg. meN = 2.65) was significantly higher than that of the dimorphicP. spadonia(avg. meN = 1.06), despite a significant paternity skew inP. rhea(avg. B = 0.10). Our findings support the idea that mating strategies of queens may co‐evolve with selection to increase the diversity of workers. We also detected patriline bias in the production of different worker sizes, which provides direct evidence for a genetic component to worker polymorphism.
De‐O‐acetylation of peptidoglycan regulates glycan chain extension and affects in vivo survival of Neisseria meningitidis
Authors: Veyrier Frédéric J. , Williams Allison H. , Mesnage Stéphane , Schmitt Christine , Taha Muhamed‐Kheir , Boneca Ivo G. 
Published: February 2013

SummaryPeptidoglycan O‐acetylation is a modification found in many bacteria. In Gram‐positive pathogens, it contributes to virulence by conferring resistance to host lysozyme. However, in Gram‐negative pathogens, its contribution to physiology and virulence is unknown. We examined the contribution of patA, patB and ape1 to peptidoglycan O‐acetylation in the major human pathogen Neisseria meningitidis (Nm). Using genetic expression of all possible combinations of the three genes in Escherichia coli and Nm, we confirmed that PatA and PatB were required for PG O‐acetylation, while ApeI removed the O‐acetyl group. ApeI was active on all O‐acetylated muropeptides produced by PatA and PatB during heterologous expression in E. coli and was also active on several PG structures in vitro. Interestingly, in Nm, ApeI was found to preferentially de‐O‐acetylate muropeptides with tripeptide stems (GM3), suggesting that its activity is highly regulated. Accordingly, de‐O‐acetylation of GM3 regulated glycan chain elongation and cell size. Additionally, the virulence of Nm lacking ApeI was drastically reduced suggesting that regulation of glycan chain length by O‐acetylation contributes to bacterial fitness in the host. Altogether, our results suggest that ApeI represents an attractive target for new drug development.
Esophageal Tissue Injury Following Pulmonary Vein Isolation Using the PVAC: Assessment by Endoscopy and Magnetic Resonance Imaging
Authors: von BARY CHRISTIAN , DORNIA CHRISTIAN , KIRCHNER GABRIELE , WEBER STEFAN , FELLNER CLAUDIA , NISENBAUM DAVID , GEORGIEVA MARTINA , STROSZCZYNSKI CHRISTIAN , HAMER OKKA W. 
Published: February 2013

BackgroundWe investigate the frequency of esophageal tissue injury (ETI) following ablation of atrial fibrillation (AF) using the pulmonary vein ablation catheter (PVAC) ascertained by esophageal endoscopy (ESE) and corresponding magnetic resonance imaging (MRI).MethodsA total of 41 patients with symptomatic AF presenting for pulmonary vein isolation (PVI) were included consecutively in two observational groups. Group A received MRI the day before and ESE plus MRI within 3–4 weeks following the ablation procedure using the PVAC. Group B received MRI the day before and ESE plus MRI within 2 days after PVI. MRI included T2‐weighted and T1‐weighted postcontrast with fat suppression (fs) and late‐enhancement scans to demonstrate postprocedural edema and contrast enhancement of the esophageal wall.ResultsA total of 13 (32%) patients were enrolled in Group A (26 ± 11 days post‐PVI), and 28 (68%) patients in Group B (2 ± 0.6 days post‐PVI). ETI was found by ESE in one (2%) patient (Group B) and resolved under conservative therapy. Corresponding MRI showed a false negative result with no alterations of esophageal structures using T1‐weighted, T2‐weighted, and late enhancement scans. In addition, false positive results were demonstrated by late‐enhancement MRI in five (12%) patients (three patients in Group A and two patients in Group B), which could not be verified by corresponding ESE.ConclusionsEndoluminal ETI is a rare but possible complication, which should be considered following PVAC procedures. MRI of the esophagus is currently not a reliable screening method due to false positive and negative findings compared to ESE.