4,619 research outputs found

    Blogging in the physics classroom: A research-based approach to shaping students' attitudes towards physics

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    Even though there has been a tremendous amount of research done in how to help students learn physics, students are still coming away missing a crucial piece of the puzzle: why bother with physics? Students learn fundamental laws and how to calculate, but come out of a general physics course without a deep understanding of how physics has transformed the world around them. In other words, they get the "how" but not the "why". Studies have shown that students leave introductory physics courses almost universally with decreased expectations and with a more negative attitude. This paper will detail an experiment to address this problem: a course weblog or "blog" which discusses real-world applications of physics and engages students in discussion and thinking outside of class. Specifically, students' attitudes towards the value of physics and its applicability to the real-world were probed using a 26-question Likert scale survey over the course of four semesters in an introductory physics course at a comprehensive Jesuit university. We found that students who did not participate in the blog study generally exhibited a deterioration in attitude towards physics as seen previously. However, students who read, commented, and were involved with the blog maintained their initially positive attitudes towards physics. Student response to the blog was overwhelmingly positive, with students claiming that the blog made the things we studied in the classroom come alive for them and seem much more relevant.Comment: 20 pages, 6 figure

    X-ray and radio observations of central black holes in nearby low-mass early-type galaxies: Preliminary evidence for low Eddington fractions

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    We present new radio and X-ray observations of two nearby (<4< 4 Mpc) low-mass early-type galaxies with dynamically-confirmed central black holes: NGC 5102 and NGC 205. NGC 5102 shows a weak nuclear X-ray source and has no core radio emission. However, for the first time we demonstrate that it shows luminous extended radio continuum emission in low-resolution, low-frequency (<3< 3 GHz) data, consistent with jet lobes on scales 100\gtrsim 100 pc formed from past accretion and jet activity. By contrast, in new, extremely deep, strictly-simultaneous Very Large Array and Chandra observations, no radio or X-ray emission is detected from the black hole in NGC 205. We consider these measurements and upper limits in the context of the few other low-mass early-type galaxies with dynamically-confirmed black holes, and show that the mean ratio of bolometric to Eddington luminosity in this sample is only log(Lbol/LEdd)=6.57±0.50\textrm{log} \, (L_{\rm bol}/L_{\rm Edd}) = -6.57\pm0.50. These Eddington ratios are lower than typical in a comparison sample of more massive early-type galaxies, though this conclusion is quite tentative due to our small sample of low-mass galaxies and potential biases in the comparison sample. This preliminary result is in mild tension with previous work using less sensitive observations of more distant galaxies, which predict higher X-ray luminosities than we observe for low-mass galaxies. If it is confirmed that central black holes in low-mass galaxies typically have low Eddington ratios, this presents a challenge to measuring the occupation fraction of central black holes with standard optical emission line, X-ray, or radio surveys.Comment: 13 pages, 4 figures, 3 tables. Accepted for publication in Ap

    Leisure-Time Sedentary Behavior, Alcohol Consumption, and Sexual Intercourse Among Adolescents Aged 12-15 Years in 19 Countries From Africa, the Americas, and Asia

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    BACKGROUND: The association between sedentary behavior and sexual behavior has not been investigated among adolescents. // AIM: The aim of this study was to: (i) investigate the association between leisure-time sedentary behavior and sexual intercourse, and (ii) test for mediation by alcohol consumption, drug use, physical activity, bullying victimization, parental support/ monitoring, loneliness, and depressive symptoms in a large global sample of young adolescents. // METHODS: Data were analyzed from 34,674 adolescents aged 12-15 years participating in the Global School-based Student Health Survey. Participants reported the number of hours spent in leisure-time sedentary behavior on a typical day (8 hours). Data on alcohol consumption, drug use, physical activity, bullying victimization, parental support/monitoring, loneliness, and depressive symptoms were considered as potential mediators. // OUTCOME: Participants reported whether or not they had sexual intercourse in the past 12 months (yes/no). // RESULTS: The prevalence of past 12-month sexual intercourse was 11.9%, whereas the prevalence of 8 hours per day of leisure-time sedentary behavior were 26.7%, 35.6%, 21.4%, 11.5%, and 4.9%, respectively. There was a dose-dependent relationship between sedentary behavior and odds of reporting sexual intercourse: compared with 8 hours/day of sedentary behavior were 1.12 (0.94-1.33), 1.22 (1.01-1.48), 1.34 (1.08-1.66), and 1.76 (1.37-2.27), respectively. There was no significant interaction by sex. The largest proportion of the association between sedentary behavior and sexual intercourse was explained by alcohol use (% mediated 21.2%), with other factors explaining an additional 11.2%. // CLINICAL TRANSLATION: Interventions to reduce leisure-time sedentary and/or alcohol consumption may contribute to a reduction in the proportion of adolescents engaging in sexual intercourse at a young age. The strengths and limitations of this study are the large, representative sample of adolescents from 19 countries. However, the cross-sectional design means causality or temporal associations could not be established. // CONCLUSIONS: In young adolescents, leisure-time sedentary behavior is positively associated with odds of having sexual intercourse in both boys and girls, in a dose-dependent manner. Alcohol consumption seems to be a key mediator of this relationship

    The colour dipole approach to small-x processes

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    We explain why it is possible to formulate a wide variety of high energy (small-x) photon-proton processes in terms of a universal dipole cross section and compare and contrast various parameterizations of this function that exist in the literature.Comment: 6 pages, latex, 2 figures. Contribution to Durham Collider Workshop (Sept 99) proceeding

    Robust stationary entanglement of two coupled qubits in independent environments

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    The dissipative dynamics of two interacting qubits coupled to independent reservoirs at nonzero temperatures is investigated, paying special attention to the entanglement evolution. The counter-rotating terms in the qubit-qubit interaction give rise to stationary entanglement, traceable back to the ground state structure. The robustness of this entanglement against thermal noise is thoroughly analyzed, establishing that it can be detected at reasonable experimental temperatures. Some effects linked to a possible reservoir asymmetry are brought to light.Comment: 8 pages, 6 figures; version accepted for publication on Eur. Phys. J.

    Ibuprofen, paracetamol, and steam for patients with respiratory tract infections in primary care: pragmatic randomised factorial trial

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    Objective: To assess strategies for advice on analgesia and steam inhalation for respiratory tract infections.Design: Open pragmatic parallel group factorial randomised controlled trial.Setting: Primary care in United Kingdom.Participants: Patients aged ?3 with acute respiratory tract infections.Intervention: 889 patients were randomised with computer generated random numbers in pre-prepared sealed numbered envelopes to components of advice or comparator advice: advice on analgesia (take paracetamol, ibuprofen, or both), dosing of analgesia (take as required v regularly), and steam inhalation (no inhalation v steam inhalation).Outcomes: Primary: mean symptom severity on days 2-4; symptoms rated 0 (no problem) to 7 (as bad as it can be). Secondary: temperature, antibiotic use, reconsultations.Results: Neither advice on dosing nor on steam inhalation was significantly associated with changes in outcomes. Compared with paracetamol, symptom severity was little different with ibuprofen (adjusted difference 0.04, 95% confidence interval ?0.11 to 0.19) or the combination of ibuprofen and paracetamol (0.11, ?0.04 to 0.26). There was no evidence for selective benefit with ibuprofen among most subgroups defined before analysis (presence of otalgia; previous duration of symptoms; temperature &gt;37.5°C; severe symptoms), but there was evidence of reduced symptoms severity benefit in the subgroup with chest infections (ibuprofen ?0.40, ?0.78 to ?0.01; combination ?0.47; ?0.84 to ?0.10), equivalent to almost one in two symptoms rated as a slight rather than a moderately bad problem. Children might also benefit from treatment with ibuprofen (ibuprofen: ?0.47, ?0.76 to ?0.18; combination: ?0.04, ?0.31 to 0.23). Reconsultations with new/unresolved symptoms or complications were documented in 12% of those advised to take paracetamol, 20% of those advised to take ibuprofen (adjusted risk ratio 1.67, 1.12 to 2.38), and 17% of those advised to take the combination (1.49, 0.98 to 2.18). Mild thermal injury with steam was documented for four patients (2%) who returned full diaries, but no reconsultations with scalding were documented.Conclusion: Overall advice to use steam inhalation, or ibuprofen rather than paracetamol, does not help control symptoms in patients with acute respiratory tract infections and must be balanced against the possible progression of symptoms during the next month for a minority of patients. Advice to use ibuprofen might help short term control of symptoms in those with chest infections and in children

    Developing a training course to teach research skills to people with learning disabilities: “It gives us a voice. We CAN be researchers!”.

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    Background Within learning disability research, it is important to involve people with learning disabilities at all stages, but there are limited opportunities for them to learn about the research process or to gain research skills. Method An eight-session research training course for people with learning disabilities was developed and piloted at a university in London. The focus was on understanding the research process and gaining practical skills in collecting, analysing and presenting research data. Training methods were experimental, with an emphasis on learning by experience in a “fun” way. Results Ten people with learning disabilities completed the course, showing great enthusiasm and commitment. During the final sessions, students developed and conducted their own research projects, choosing “Employment” as their research topic. The training methods were well received. Benefits included an increase in confidence and new work opportunities for several of the students. This paper was co-authored by the tutors and most of the course graduates. Conclusion It is possible for people with learning disabilities to become skilled researchers, but in order to do so, it is important that they have adequate training opportunities. Funding should be made available for more such courses
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