355 research outputs found

    Language Comprehension as an Effect of Aging and Hand Preference Using the Computerized Revised Token Test-Reading-Word Fade

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    Aims: The Computerized Revised Token Test (CRTT) is a standardized assessment of language comprehension and processing abilities. The CRTT-Reading-Word-Fade (CRTT-R-WF) is a self-paced version of the CRTT in which the previous word in a sentence disappears with the onset of each new word. In addition to the language skills needed to complete the assessment, the CRTT also requires perceptual-motor and cognitive capabilities that have the potential to negatively influence participant results. The purpose of this study was to investigate the effect of age and hand preference as two of these potential influences on CRTT performance. Methods: Sixty-four healthy, normal adults participated in this study. Participants were divided into two groups: younger adults (Group 1, 20-32 years) and older adults (Group 2, 65-78 years). Each group consisted of 32 participants (16 males and 16 females). All 64 participants completed the CRTT-R-WF version of the CRTT and CRTT-RT battery with both their right and left hand. The CRTT-R-WF mean scores, efficiency scores, and reading times were investigated to evaluate the effects of age and hand preference on the accuracy and efficiency of participant responses. Results: Statistically significant main effects were observed for both age and hand use on CRTT-R-WF mean scores, efficiency scores, and reading plus response times. The older adults demonstrated significantly lower mean and efficiency scores, as well as significantly slower reading times. Mean scores, efficiency scores and reading plus response times achieved with the left hand were also significantly lower and slower than the right hand across participants. Significant interactions between age and hand were found on CRTT-R-WF mean and efficiency scores. The older adult’s mean and efficiency scores were over-additively reduced with their left hand. Discussion: Decreased comprehension and efficiency of responses, as measured by the CRTT-R-WF, were observed with age and with non-preferred hand use with a computer mouse. Slower reading plus response times were also observed as an effect of age. Theories of working memory, processing speed, and resource allocation were discussed as possible explanations as to why these results were observed

    Prédicteurs de réussite en sciences : attitudes, valeurs et expériences antérieures des élèves en 8e année dans les programmes d'immersion française au Canada

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    Peu d'études ont examiné les résultats en sciences dans les programmes d'immersion française, malgré les différences entre les élèves de cette filière et leurs homologues du programme anglais régulier en termes de statut socio-économique moyen et de sexe - qui se sont tous deux avérés avoir un impact sur les résultats scolaires. Le rapport du PPCE (Programme pancanadien d'évaluation) 2013, Rapport de l'évaluation pancanadienne en science, en lecture et en mathématiques, a identifié six prédicteurs non cognitifs de la réussite scolaire en sciences chez les élèves de 8e année. Ces prédicteurs comprennent l'attitude à l'égard de la science, l'évaluation personnelle de ses aptitudes en sciences, l'expérience antérieure des sciences, l'importance des sciences au regard des objectifs de l’élève et de la société, la compréhension de la nature des sciences et des méthodes scientifiques, et la tendance au fatalisme (corrélé négativement avec la réussite). Nous avons cherché à déterminer si des différences dans ces attitudes, valeurs et expériences d'apprentissage existent entre les élèves des écoles anglophones qui étudient en immersion française et ceux qui étudient dans le programme régulier (anglais) au Canada. À partir de ces données du PPCE 2013, des comparaisons entre groupes ont été effectuées en utilisant l'ANCOVA pour contrôler le sexe et les indicateurs de statut socio-économique, suivies d'une régression logistique binaire. En plus de trouver des écarts significatifs dans les résultats scientifiques entre les deux groupes, nous avons identifié des différences significatives entre les scores moyens pour l'importance des sciences au regard des objectifs de l'élève et de la société et la compréhension de la nature des sciences et des méthodes scientifiques. Nous avons également constaté que sur les six variables présentées par le PPCE 2013 les seuls prédicteurs de la réussite en sciences n'étaient que l'Attitude de l'élève à l'égard des sciences, les Expériences antérieures des sciences et la Tendance au fatalisme, la variable de contrôle Nombre de livres à la maison présentant également un pouvoir prédictif significatif pour la réussite. La discussion tient également compte des différences de sexe et des différences socio-économiques entre ces deux programmes, en considérant celles-ci et d'autres raisons possibles pour expliquer les différences entre les groupes et leur rôle dans l'écart de réussite en sciences ainsi que les différences d'attitude, de valeurs et d'expériences antérieures des élèves explorées par cette analyse.Few studies have examined science achievement in French immersion programs, despite the differences between students in French Immersion and their English stream counterparts in terms of their average socioeconomic status and gender –which have both been shown to impact academic achievement. The PCAP (Pan-Canadian Assessment Program) 2013 Report on the Pan-Canadian Assessment of Science, Reading, and Mathematics identified six non-cognitive predictors of academic achievement in science among 8th-grade students. These predictors include attitude toward science, science self-efficacy, experience with science in early years, the value of science to the goals of the student and to society, the understanding what science is and how it is done, and tendency to fatalism. We sought to determine whether differences in these attitudes, values, and learning experiences exist between students who study in French immersion and those in the English stream in anglophone schools across Canada. Using these PCAP 2013 data, between-group comparisons were made using analysis by covariance (ANCOVA) to control for gender and indicators of socio-economic status, followed by a binary logistic regression, controlling for the same. Beyond identifying significant gaps in science achievement between the two groups, we identified statistically significant differences between the mean scores for Importance of science and Comprehension of the nature of science and scientific methodologies. We also found that, of the six variables presented by the PCAP 2013, significant predictive power with regards to success in science was only present for Attitude toward science, Previous experiences with science, and Tendency to fatalism, with the control variable Number of books at home also presenting significant predictive power for success. The discussion takes gender and socioeconomic differences between these two anglophone sub-populations into account while considering and other possible reasons as explanation for the between-group differences and their role in the science achievement gap as well as the differences in attitude, values and previous experiences of students explored through this analysis

    Noise Impacts from Professional Dog Grooming Forced-Air Dryers

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    This study was designed to measure the sound output of four commonly used brands of forced-air dryers used by dog groomers in the United States. Many dog groomers have questions about the effect of this exposure on their hearing, as well as on the hearing of the dogs that are being groomed. Readings taken from each dryer at 1 meter (the likely distance of the dryer from the groomer and the dog) showed average levels ranging from 105.5 to 108.3 dB SPL or 94.8 to 108.0 dBA. Using the 90 dBA criterion required by the US Occupational Safety and Health Administration, dog groomers/bathers are at risk if exposure to the lowest intensity dryer (94.8 dBA) exceeds 4 hours per day. If the more stringent 85 dBA criterion and 3 dB tradeoff is applied, less than one hour of exposure is permissible in an 8 hour day. Cautions are recommended for any persons exposed to noise from forced-air dryers

    An Always Correlated gene expression landscape for ovine skeletal muscle, lessons learnt from comparison with an “equivalent” bovine landscape

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    BACKGROUND: We have recently described a method for the construction of an informative gene expression correlation landscape for a single tissue, longissimus muscle (LM) of cattle, using a small number (less than a hundred) of diverse samples. Does this approach facilitate interspecies comparison of networks? FINDINGS: Using gene expression datasets from LM samples from a single postnatal time point for high and low muscling sheep, and from a developmental time course (prenatal to postnatal) for normal sheep and sheep exhibiting the Callipyge muscling phenotype gene expression correlations were calculated across subsets of the data comparable to the bovine analysis. An “Always Correlated” gene expression landscape was constructed by integrating the correlations from the subsets of data and was compared to the equivalent landscape for bovine LM muscle. Whilst at the high level apparently equivalent modules were identified in the two species, at the detailed level overlap between genes in the equivalent modules was limited and generally not significant. Indeed, only 395 genes and 18 edges were in common between the two landscapes. CONCLUSIONS: Since it is unlikely that the equivalent muscles of two closely related species are as different as this analysis suggests, within tissue gene expression correlations appear to be very sensitive to the samples chosen for their construction, compounded by the different platforms used. Thus users need to be very cautious in interpretation of the differences. In future experiments, attention will be required to ensure equivalent experimental designs and use cross-species gene expression platform to enable the identification of true differences between different species

    Horizontal Transmission and Recombination Maintain forever Young Bacterial Symbiont Genomes

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    Bacterial symbionts bring a wealth of functions to the associations they participate in, but by doing so, they endanger the genes and genomes underlying these abilities. When bacterial symbionts become obligately associated with their hosts, their genomes are thought to decay towards an organelle-like fate due to decreased homologous recombination and inef- ficient selection. However, numerous associations exist that counter these expectations, especially in marine environments, possibly due to ongoing horizontal gene flow. Despite extensive theoretical treatment, no empirical study thus far has connected these underlying population genetic processes with long-term evolutionary outcomes. By sampling marine chemosynthetic bacterial-bivalve endosymbioses that range from primarily vertical to strictly horizontal transmission, we tested this canonical theory. We found that transmission mode strongly predicts homologous recombination rates, and that exceedingly low recombination rates are associated with moderate genome degradation in the marine symbionts with nearly strict vertical transmission. Nonetheless, even the most degraded marine endosym- biont genomes are occasionally horizontally transmitted and are much larger than their ter- restrial insect symbiont counterparts. Therefore, horizontal transmission and recombination enable efficient natural selection to maintain intermediate symbiont genome sizes and sub- stantial functional genetic variation

    A Longitudinal Study of Pediatricians Early in their Careers: PLACES

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    The American Academy of Pediatrics (AAP) launched the Pediatrician Life and Career Experience Study (PLACES), a longitudinal study that tracks the personal and professional experiences of early career pediatricians, in 2012. We used a multipronged approach to develop the study methodology and survey domains and items, including review of existing literature and qualitative research with the target population. We chose to include 2 cohorts of US pediatricians on the basis of residency graduation dates, including 1 group who were several years out of residency (2002–2004 Residency Graduates Cohort) and a second group who recently graduated from residency at study launch (2009–2011 Residency Graduates Cohort). Recruitment into PLACES was a 2-stage process: (1) random sample recruitment from the target population and completion of an initial intake survey and (2) completion of the first Annual Survey by pediatricians who responded positively to stage 1. Overall, 41.2% of pediatricians randomly selected to participate in PLACES indicated positive interest in the study by completing intake surveys; of this group, 1804 (93.7%) completed the first Annual Survey and were considered enrolled in PLACES. Participants were more likely to be female, AAP members, and graduates of US medical schools compared with the target sample; weights were calculated to adjust for these differences. We will survey PLACES pediatricians 2 times per year. PLACES data will allow the AAP to examine career and life choices and transitions experienced by early-career pediatricians

    Differing responses of red abalone (Haliotis rufescens) and white abalone (H. sorenseni) to infection with phage-associated Candidatus Xenohaliotis californiensis

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    The Rickettsiales-like prokaryote and causative agent of Withering Syndrome (WS)—Candidatus Xenohaliotis californiensis (Ca. Xc)—decimated black abalone populations along the Pacific coast of North America. White abalone—Haliotis sorenseni—are also susceptible to WS and have become nearly extinct in the wild due to overfishing in the 1970s. Candidatus Xenohaliotis californiensis proliferates within epithelial cells of the abalone gastrointestinal tract and causes clinical signs of starvation. In 2012, evidence of a putative bacteriophage associated with Ca. Xc in red abalone—Haliotis rufescens—was described. Recently, histologic examination of animals with Ca. Xc infection in California abalone populations universally appear to have the phage-containing inclusions. In this study, we investigated the current virulence of Ca. Xc in red abalone and white abalone at different environmental temperatures. Using a comparative experimental design, we observed differences over time between the two abalone species in mortality, body condition, and bacterial load by quantitative real time PCR (qPCR). By day 251, all white abalone exposed to the current variant of Ca. Xc held in the warm water (18.5 °C) treatment died, while red abalone exposed to the same conditions had a mortality rate of only 10%, despite a relatively heavy bacterial burden as determined by qPCR of posterior esophagus tissue and histological assessment at the termination of the experiment. These data support the current status of Ca. Xc as less virulent in red abalone, and may provide correlative evidence of a protective phage interaction. However, white abalone appear to remain highly susceptible to this disease. These findings have important implications for implementation of a white abalone recovery program, particularly with respect to the thermal regimes of locations where captively-reared individuals will be outplanted

    Dynamics of growth factor production in monolayers of cancer cells and evolution of resistance to anticancer therapies

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    Tumor heterogeneity is well documented for many characters, including the production of growth factors, which improve tumor proliferation and promote resistance against apoptosis and against immune reaction. What maintains heterogeneity remains an open question that has implications for diagnosis and treatment. While it has been suggested that therapies targeting growth factors are robust against evolved resistance, current therapies against growth factors, like antiangiogenic drugs, are not effective in the long term, as resistant mutants can evolve and lead to relapse. We use evolutionary game theory to study the dynamics of the production of growth factors by monolayers of cancer cells and to understand the effect of therapies that target growth factors. The dynamics depend on the production cost of the growth factor, on its diffusion range and on the type of benefit it confers to the cells. Stable heterogeneity is a typical outcome of the dynamics, while a pure equilibrium of nonproducer cells is possible under certain conditions. Such pure equilibrium can be the goal of new anticancer therapies. We show that current therapies, instead, can be effective only if growth factors are almost completely eliminated and if the reduction is almost immediate
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