89 research outputs found

    Characterization of the transport properties of MoO3 films on copper

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    In this study we report the first transport experiments performed on a series of thin films of MoO3 grown on a thick Cu substrate. Electrical resistance measurements have been performed for different film thickness as function of temperature down to ∌20 K. Data show, due to the copper substrate, that thin films of molybdenum trioxide also at low temperature exhibits a metallic behaviour while for films with a thickness > 250 nm the semiconducting behaviour start to prevail on the metallic one. Local morphological properties and optical data are also showed to support the interpretation of the conductive behaviour of these thin layers of molybdenum oxides

    Effects of open (Racket) and closed (running) skill sports practice on children’s attentional performance

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    Aims: The first aim of the study was to examine the attentional performance of children (8–13 years of age) who practiced two different sport disciplines: Open skill sport – racket and closed skill sport – running and also to investigate the acute effects of these two specific training sessions on children’s immediate and delayed attentional performance. The second aim of the present study was to verify gender differences in attentional performance. Eighteen children+ (8 girls and 10 boys; age = 10.6 ± 1.5 yrs; height = 144.3 ± 12.2 cm; weight = 44.2 ± 12.5 kg; BMI = 20.8 ± 2.7 kg/m2) engaged in a racket sports and eighteen children (9 girls and 9 boys; age = 9.9 ± 1.2 yrs; height = 142.4 ± 9.5 cm; weight = 40.0 ± 8.6 kg; BMI = 19.6 ± 2.4 kg/m2) engaged in running were enrolled. Methods: Children’s training and experience with these activities averaged 2.3 (± 1.0) years. Children’s attentional capacity was measured before, immediately after and 50 minutes after each specific training session by the d2 test of attention. This paper-and-pencil letter cancellation test evaluated concentration and sustained attention under stress induced by a fixed executing time. A 2 (Sport: open vs closed skill) x 2 (Gender: boys vs girls) x 3 (Time: pre vs 0’ post vs 50’ post) repeated measures ANOVA for time was used to compare the effect of an open skill session and a closed skill session on the individual attentional variables. Results: Children of open skill sport showed higher attentional scores (higher processing speed-TN, higher concentration performance-CP and lower percentage of errors-E%; p < 0.01), improved CP from pre to 0’ post intervention (p = 0.01) and maintained this improved performance at 50’ post intervention (50’ post vs pre; p < 0.01), and decreased E% from pre to 0’ post intervention (p = 0.01) and maintained this improvement at 50’ post intervention (50’ post vs pre; p < 0.001). Children of closed skill sport significantly decreased their CP from pre to 50’ post intervention (50’ post vs pre; p = 0.001 and 50’ post vs 0’ post; p < 0.0001) and worsened their E% across the time (50’ post vs pre; p = 0.001 and 50’ post vs 0’ post; p < 0.0001). Boys showed significantly higher TN values than girls only in closed skill sport (p = 0.023). Finally, all girls of both open and closed skill sports significantly improved their CP from pre to 0’ post intervention (p = 0.04). Conclusion: Results of the study showed that open skill sport practice and training session positively affects children’s attentional performance

    Recurrence quantification analysis of heart rate variability to detect both ventilatory thresholds

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    Aims of this study were: To verify if Recurrence Quantification Analysis (RQA) of Heart Rate Variability (HRV) time series could determine both ventilatory thresholds in individuals with different fitness levels, and to assess the validity of RQA method compared to gasexchange method (GE). The two thresholds were estimated in thirty young individuals during incremental exercise on cycle-ergometer: Heart rate (HR), Oxygen consumption (VO2) and Workload were measured by the two methods (RQA and GE). Repeated measures ANOVA was used to assess main effects of methods and methods-by-groups interaction effects for HR, VO2 and Workload at aerobic (AerT) and anaerobic (AnT) thresholds. Validity of RQA at both thresholds was assessed for HR, VO2 and Workload by Ordinary Least Products (OLP) regression, Typical Percentage Error (TE), Intraclass Correlation Coefficients (ICC) and the Bland Altman plots. No methods-by-groups interaction effects were detected for HR, VO2 and Workload at AerT and AnT. The OLP analysis showed that at both thresholds RQA and GE methods had very strong correlations (r >0.8) in all variables (HR, VO2 and Workload). Slope and intercept values always included the 1 and the 0, respectively. At AerT the TE ranged from 4.02% (5.48 bpm) to 10.47% (8.53 Watts) (HR and Workload, respectively) and in all variables ICC values were excellent (≄0.85). At AnT the TE ranged from 2.53% (3.98 bpm) to 6.64% (7.81 Watts) (HR and Workload, respectively) and in all variables ICC values were excellent (≄0.90). Therefore, RQA of HRV time series is a new valid approach to determine both ventilatory thresholds in individuals with different physical fitness levels, it can be used when gas analysis is not possible or not convenient

    High School Student Athletes and Nonathletes\u27 Disciplinary Referrals and Grade Point Averages

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    High School Student Athletes and Nonathletes\u27 Disciplinary Referrals and Grade Point Averages by Jack Calhoun MEd, Georgia Southwestern State University, 1998 BS, Georgia Southwestern State University, 1997 Doctoral Study Submitted in Partial Fulfillment of the Requirements for the Degree of Doctor of Education Walden University December 2014 This quantitative study investigated how athletic participation in public high schools influenced students\u27 academic achievement and positive social behavior. Disciplinary referrals are on the rise in American schools and are a cause of concern for teachers, administrators, parents, and community members. School personnel currently implement programs designed to curb discipline problems in the classroom and foster productive behavior among adolescents. There is some debate and conflicting literature on whether sports participation has a beneficial influence on students. The writings of Virgina Chomitz, who hypothesized a positive relationship between academic achievement and physical fitness, guided this research. This study analyzed grade point average (GPA) and discipline referral data for 4,433 students in a suburban American high school over a 3-year time period. The GPA and referral data for athletes and nonathletes were compared using multiple t tests, and it was found that athletes had significantly higher GPAs and lower discipline referrals when compared to nonathletes. These results, which match the original hypotheses, provide greater insight into how participating in athletics may improve a student\u27s behavior and academic achievement. With this knowledge, educators may place greater emphasis on athletics as a method to promote achievement and positive experiences among high school students. These positive effects will contribute to social change for students at an individual level and for entire school environments

    EU-DEMO divertor: Cassette design and PFCs integration at pre-conceptual stage

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    The pre-conceptual design of the DEMO divertor cassette with a novelty, alternative path of the main cooling pipes inside cassette body is presented in this paper, focusing on cassette design and Plasma Facing Components (PFC) integration. The divertor cassette design is reviewed, considering recent updates in the DEMO configuration model as presented by the Programme Management Unit (PMU) in 2018. The new configuration requires the cooling pipes to be integrated inside the cassette body. The components affected by these changes and the impact on the divertor design are analyzed. The study focuses on a new integration system between cassette and cooling pipes. The paper describes the integration on the new cassette geometry and the divertor sub-systems. The design activities related to this system are discussed in detail in terms of CAD modeling and considerations with respect to manufacturing such as welding technologies and non-destructive testing

    Eurofusion-DEMO Divertor - Cassette Design and Integration

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    The Eurofusion-DEMO design will complete the Pre Conceptual Design phase (PCD) with a PCD Gate, named G1, scheduled to take place in Q4 2020 that will focus on assessing the feasibility of the plant and its main components prior to entering into the Conceptual Design phase. In the paper first an overview is given of the Eurofusion-DEMO Divertor Assembly including design and interface description, systems and functional requirements, load specification, system classification, manufacturing procedures and cost estimate. Then critical issues are discussed and potential design solutions are proposed, e.g.: - Neutron material damage limits of the different (structural) materials present in the divertor assembly (as CuCrZr, Eurofer) and in the vacuum vessel (AISI 316 L(N)-IG); - Temperature hot spots in parts of the divertor assembly exposed to high nuclear heating and high heat radiation (from the plasma core or the separatrix) causing difficulties for active or passive cooling (e.g. cassette body structure, liner support structures, mechanical supports, divertor toroidal rails); - Arrangement and design of plasma-facing components and liner with pumping slot in the divertor cassette to enable pumping of exhaust gases from the lower port

    Vascular risk factors in glaucoma: the results of a national survey

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    Background The role of vascular risk factors in glaucoma is still being debated. To assess the importance of vascular risk factors in patients with primary open-angle glaucoma (POAG), data from the medical history of 2,879 POAG patients and 973 age-matched controls were collected and analyzed. Methods Design: observational survey. Setting: 35 Italian academic centers. Study population: POAG patients and age-matched controls. In order to reduce bias consecutive patients were included. Observation procedures: data concerning vascular risk factors were collected for all patients with a detailed questionnaire. A complete ophthalmological examination with assessment of intraocular pressure (IOP), visual field, optic disc, and systemic blood pressure was performed. Main outcome measures: the ESH-ESC (European Society of Hypertension-European Society of Cardiology) guidelines were used to calculate the level of cardiovascular risk. Crude and adjusted estimates of the odds ratios (OR) were calculated for all cardiovascular risk factors in POAG and controls. Results The study included 2,879 POAG patients and 973 controls. POAG cases had a significantly higher systolic and diastolic blood pressure (p=0.001) and systolic perfusion pressure (p=0.02) as compared with controls. Also mean IOP was significantly higher in the POAG group (p=0.01), while diastolic perfusion pressure was not significantly different in the two groups. Myopia was more prevalent in the POAG group (23 vs 18%, p=0.005) as well as a positive family history for glaucoma (26 vs 12%, p= 0.004). POAG patients tended to have a higher cardiovascular risk than controls: 63% of glaucoma cases vs 55% of controls (OR: 1.38, p=0.005) had a “high” or “very high” cardiovascular risk. Conclusions The level of cardiovascular risk was significantly higher in glaucoma patients than in controls
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