414 research outputs found

    How New Caledonian crows solve novel foraging problems and what it means for cumulative culture.

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    New Caledonian crows make and use tools, and tool types vary over geographic landscapes. Social learning may explain the variation in tool design, but it is unknown to what degree social learning accounts for the maintenance of these designs. Indeed, little is known about the mechanisms these crows use to obtain information from others, despite the question's importance in understanding whether tool behavior is transmitted via social, genetic, or environmental means. For social transmission to account for tool-type variation, copying must utilize a mechanism that is action specific (e.g., pushing left vs. right) as well as context specific (e.g., pushing a particular object vs. any object). To determine whether crows can copy a demonstrator's actions as well as the contexts in which they occur, we conducted a diffusion experiment using a novel foraging task. We used a nontool task to eliminate any confounds introduced by individual differences in their prior tool experience. Two groups had demonstrators (trained in isolation on different options of a four-option task, including a two-action option) and one group did not. We found that crows socially learn about context: After observers see a demonstrator interact with the task, they are more likely to interact with the same parts of the task. In contrast, observers did not copy the demonstrator's specific actions. Our results suggest it is unlikely that observing tool-making behavior transmits tool types. We suggest it is possible that tool types are transmitted when crows copy the physical form of the tools they encounter.We are grateful to our funders: the SAGE Center for the Study of the Mind at the University of California Santa Barbara and the National Geographic Society/Waitt Grants Program (CJL), a Rutherford Discovery Fellowship from the Royal Society of New Zealand (AHT), the Marsden Fund (RG), and a BBSRC grant (WH; BB/I007997/1).This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.3758/s13420-015-0194-

    Multi-scenario modelling of learning

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    International audienceDesigning an educational scenario is a sensitive and challenging activity because it is the vector of learning. However, the designed scenario may not correspond to some learners’ characteristics (pace of work, cognitive styles, emotional factors, prerequisite knowledge, …). To personalize the learning task and adapt it gradually to each learner, several scenarios are needed. Adaptation and personalization are difficult because it is necessary on the one hand to know in advance the profiles and on the other hand to produce the multiple scenarios corresponding to these profiles. Our model allows to design many scenarios without knowing the learner profiles beforehand. Furthermore, it offers each learner opportunities to choose a scenario and to change it during their learning process. The model ensures that all announced objectives have enough resources for acquiring knowledge and activities for evaluation

    Does inter-vertebral range of motion increase after spinal manipulation? A prospective cohort study.

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    Background: Spinal manipulation for nonspecific neck pain is thought to work in part by improving inter-vertebral range of motion (IV-RoM), but it is difficult to measure this or determine whether it is related to clinical outcomes. Objectives: This study undertook to determine whether cervical spine flexion and extension IV-RoM increases after a course of spinal manipulation, to explore relationships between any IV-RoM increases and clinical outcomes and to compare palpation with objective measurement in the detection of hypo-mobile segments. Method: Thirty patients with nonspecific neck pain and 30 healthy controls matched for age and gender received quantitative fluoroscopy (QF) screenings to measure flexion and extension IV-RoM (C1-C6) at baseline and 4-week follow-up between September 2012-13. Patients received up to 12 neck manipulations and completed NRS, NDI and Euroqol 5D-5L at baseline, plus PGIC and satisfaction questionnaires at follow-up. IV-RoM accuracy, repeatability and hypo-mobility cut-offs were determined. Minimal detectable changes (MDC) over 4 weeks were calculated from controls. Patients and control IV-RoMs were compared at baseline as well as changes in patients over 4 weeks. Correlations between outcomes and the number of manipulations received and the agreement (Kappa) between palpated and QF-detected of hypo-mobile segments were calculated. Results: QF had high accuracy (worst RMS error 0.5o) and repeatability (highest SEM 1.1o, lowest ICC 0.90) for IV-RoM measurement. Hypo-mobility cut offs ranged from 0.8o to 3.5o. No outcome was significantly correlated with increased IV-RoM above MDC and there was no significant difference between the number of hypo-mobile segments in patients and controls at baseline or significant increases in IV-RoMs in patients. However, there was a modest and significant correlation between the number of manipulations received and the number of levels and directions whose IV-RoM increased beyond MDC (Rho=0.39, p=0.043). There was also no agreement between palpation and QF in identifying hypo-mobile segments (Kappa 0.04-0.06). Conclusions: This study found no differences in cervical sagittal IV-RoM between patients with non-specific neck pain and matched controls. There was a modest dose-response relationship between the number of manipulations given and number of levels increasing IV-RoM - providing evidence that neck manipulation has a mechanical effect at segmental levels. However, patient-reported outcomes were not related to this

    Effect of concurrent vitamin A and iodine deficiencies on the thyroid-pituitary axis in rats

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    OBJECTIVE: Deficiencies of vitamin A and iodine are common in many developing countries. Vitamin A deficiency (VAD) may adversely affect thyroid metabolism. The study aim was to investigate the effects of concurrent vitamin A and iodine deficiencies on the thyroid-pituitary axis in rats. DESIGN: Weanling rats (n = 56) were fed diets deficient in vitamin A (VAD group), iodine (ID group), vitamin A and iodine (VAD + ID group), or sufficient in both vitamin A and iodine (control) for 30 days in a pair-fed design. Serum retinol (SR), thyroid hormones (FT(4), TT(4), FT(3), and TT(3)), serum thyrotropin (TSH), pituitary TSHbeta mRNA expression levels, and thyroid weights were determined at the end of the depletion period. MAIN OUTCOME: Compared to the control and ID groups, SR concentrations were about 35% lower in the VAD and VAD + ID groups (p < 0.001), indicating moderate VA deficiency. Comparing the VAD and control groups, there were no significant differences in TSH, TSHbeta mRNA, thyroid weight, or thyroid hormone levels. Compared to the control group, serum TSH, TSHbeta mRNA, and thyroid weight were higher (p < 0.05), and FT4 and TT4 were lower (p < 0.001), in the VAD + ID and ID groups. Compared to the ID group, TSH, TSHbeta mRNA, and thyroid weight were higher (p < 0.01) and FT(4) and TT(4) were lower (p < 0.001) in the VAD + ID group. There were no significant differences in TT3 or FT3 concentrations among groups. CONCLUSION: Moderate VAD alone has no measurable effect on the pituitary-thyroid axis. Concurrent ID and VAD produce more severe primary hypothyroidism than ID alone

    Who Benefits Most from a University Degree?: A Cross-National Comparison of Selection and Wage Returns in the US, UK, and Germany

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    Recent research on economic returns to higher education in the United States suggests that those with the highest wage returns to a college degree are least likely to obtain one. We extend the study of heterogeneous returns to tertiary education across multiple institutional contexts, investigating how the relationship between wage returns and the propensity to complete a degree varies by the level of expansion, differentiation, and cost of higher education. Drawing on panel data and matching techniques, we compare findings from the US with selection into degree completion in Germany and the UK. Contrary to previous studies, we find little evidence for population level heterogeneity in economic returns to higher education

    Back pain outcomes in primary care following a practice improvement intervention:- a prospective cohort study

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    <p>Abstract</p> <p>Background</p> <p>Back pain is one of the UK's costliest and least understood health problems, whose prevalence still seems to be increasing. Educational interventions for general practitioners on back pain appear to have had little impact on practice, but these did not include quality improvement learning, involve patients in the learning, record costs or document practice activities as well as patient outcomes.</p> <p>Methods</p> <p>We assessed the outcome of providing information about quality improvement techniques and evidence-based practice for back pain using the Clinical Value Compass. This included clinical outcomes (Roland and Morris Disability Questionnaire), functional outcomes, costs of care and patient satisfaction. We provided workshops which used an action learning approach and collected before and after data on routine practice activity from practice electronic databases. In parallel, we studied outcomes in a separate cohort of patients with acute and sub-acute non-specific back pain recruited from the same practices over the same time period. Patient data were analysed as a prospective, split-cohort study with assessments at baseline and eight weeks following the first consultation.</p> <p>Results</p> <p>Data for 1014 patients were recorded in the practice database study, and 101 patients in the prospective cohort study. We found that practice activities, costs and patient outcomes changed little after the intervention. However, the intervention was associated with a small, but statistically significant reduction in disability in female patients. Additionally, baseline disability, downheartedness, self-rated health and leg pain had small but statistically significant effects (p < 0.05) on follow-up disability scores in some subgroups.</p> <p>Conclusions</p> <p>GP education for back pain that both includes health improvement methodologies and involves patients may yield additional benefits for some patients without large changes in patterns of practice activity. The effects in this study were small and limited and the reasons for them remain obscure. However, such is the impact of back pain and its frequency of consultation in general practice that this kind of improvement methodology deserves further consideration.</p> <p>Trial registration number</p> <p>ISRCTN: <a href="http://www.controlled-trials.com/ISRCTN30420389">ISRCTN30420389</a></p

    Contrastive prosody and the subsequent mention of alternatives during discourse processing

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    Linguistic research has long viewed prosody as an important indicator of information structure in intonationally rich languages like English. Correspondingly, numerous psycholinguistic studies have shown significant effects of prosody, particularly with respect to the immediate processing of a prosodically prominent phrase. Although co-reference resolution is known to be influenced by information structure, it has been less clear whether prosodic prominence can affect decisions about next mention in a discourse, and if so, how. We present results from an open-ended story continuation task, conducted as part of a series of experiments that examine how prosody influences the anticipation and resolution of co-reference. Overall results from the project suggest that prosodic prominence can increase or decrease reference to a saliently pitch-accented phrase, depending on additional circumstances of the referential decision. We argue that an adequate account of prosody’s role in co-reference requires consideration of how the processing system interfaces with multiple levels of linguistic representation

    A high density linkage map of the bovine genome

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    <p>Abstract</p> <p>Background</p> <p>Recent technological advances have made it possible to efficiently genotype large numbers of single nucleotide polymorphisms (SNPs) in livestock species, allowing the production of high-density linkage maps. Such maps can be used for quality control of other SNPs and for fine mapping of quantitative trait loci (QTL) via linkage disequilibrium (LD).</p> <p>Results</p> <p>A high-density bovine linkage map was constructed using three types of markers. The genotypic information was obtained from 294 microsatellites, three milk protein haplotypes and 6769 SNPs. The map was constructed by combining genetic (linkage) and physical information in an iterative mapping process. Markers were mapped to 3,155 unique positions; the 6,924 autosomal markers were mapped to 3,078 unique positions and the 123 non-pseudoautosomal and 19 pseudoautosomal sex chromosome markers were mapped to 62 and 15 unique positions, respectively. The linkage map had a total length of 3,249 cM. For the autosomes the average genetic distance between adjacent markers was 0.449 cM, the genetic distance between unique map positions was 1.01 cM and the average genetic distance (cM) per Mb was 1.25.</p> <p>Conclusion</p> <p>There is a high concordance between the order of the SNPs in our linkage map and their physical positions on the most recent bovine genome sequence assembly (Btau 4.0). The linkage maps provide support for fine mapping projects and LD studies in bovine populations. Additionally, the linkage map may help to resolve positions of unassigned portions of the bovine genome.</p
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