8,433 research outputs found

    The politics of the doorstep : female survival strategies and the legacy of the miners’ strike 1984–85.

    Get PDF
    This paper considers the legacy of continuing activism of women in the North East of England who organized in support of the 1984-85 miners' strike. It refers to the traditional responsibility of women in mining localities for the maintenance of neighbourhood and kin relations and using the example of a key activist in one ex-mining village, it argues that the values associated with 'mining community' remain relevant as a reference point for a self-conscious, politicized reshaping of local relationships in post-industrial conditions. The material basis for this self-conscious approach has shifted from the masculine sphere of mining work and its associated community institutions to the feminized sphere of location and neighbourhood

    Quark Model Calculations Of Symmetry Breaking in Parton Distributions

    Get PDF
    Using a quark model, we calculate symmetry breaking effects in the valence quark distributions of the nucleon. In particular, we examine the breaking of the quark model SU(4) symmetry by color magnetic effects, and find that color magnetism provides an explanation for deviation of the ratio dV(x)/uV(x)d_V(x)/u_V(x) from 1/21/2. Additionally, we calculate the effect of charge symmetry breaking in the valence quark distributions of the proton and neutron and find, in contrast to other authors, that the effect is too small to be seen experimentally.Comment: 6 Pages, 3 postscript figures compressed using uufile

    Inclusion of non-spherical components of the Pauli blocking operator in (p,p') reactions

    Full text link
    We present the first calculations of proton elastic and inelastic scattering in which the Pauli blocking operator contains the leading non-spherical components as well as the usual spherical (angle-averaged) part. We develop a formalism for including the contributions to the effective nucleon-nucleon interaction from the resulting new G-matrix elements that extend the usual two-nucleon spin structure and may not conserve angular momentum. We explore the consequences of parity conservation, time reversal invariance, and nucleon-nucleon antisymmetrization for the new effective interaction. Changes to the calculated cross section and spin observables are small in the energy range from 100 to 200 MeV.Comment: 24 pages, 4 figures, to be published in Physical Review

    The influence of hamstring extensibility on preselected saddle height within experienced competitive cyclists

    Get PDF
    Background: Contemporary studies have investigated the effects of bicycle saddle height for optimal performance and injury prevention. A recent review established a dynamic knee flexion angle of 25˚-30˚ for optimal economy, anaerobic power, and knee tracking (Bini et al., 2011: Sports Medicine, 41, 463-476). Muyor et al, (2011: Journal of Human Kinetics, 29, 15-23), investigated hamstring extensibility within 96 highly trained cyclists. They concluded that shortened hamstrings had a negative influence over thoracic spinal curvature, yet no influence over saddle height. Whereas, Ferrer-Roca et al (2012: Journal of Strength and Conditioning Research, 26, 3025- 3029) examined 23 high level competitive male road cyclists and concluded that a lack of flexibility may have an influence over lower preselected saddle heights (> 40˚ knee flexion angle). Consequently, there remains uncertainty whether preselected saddle height may be dependent on hamstring extensibility. Purpose: The purpose of the study was to investigate the influence of hamstring extensibility on preselected saddle height within experienced competitive cyclists. It was suggested that preselected saddle height may be dependent on hamstring extensibility to enable a 25˚-30˚ knee flexion angle. Methods: Participants consisted of 32 moderate to high level male and female road cyclists (35.8 ± 8.4 years; 178.22 ± 11.0 cm; 77.7 ± 13.4 kg). They used their own individually set-up road bicycle, which was placed on an indoor wind trainer. Hamstring extensibility was measured using the passive knee extension test. Dynamic 2D analysis was used to measure bicycle knee flexion and passive knee extension angles. A cycling questionnaire was also used to determine experience, training and competition levels. Results: Pearson’s correlation coefficients revealed bicycle knee flexion angle, years cycling (r = -0.35, p 0.05). Discussion: Results suggest that sustained time period on the bike rather than hamstring extensibility determines preselected saddle height. In particular, being competitive for a longer duration precedes either volume or number of years cycling. However, it is apparent that in agreement with Muyor et al., (2011) a single variable such as hamstring length does not predetermine optimal saddle height. In addition, as suggested by Ferrer-Roca et al., (2012), experienced cyclists are unable to achieve a knee flexion angle of 25˚, unless they have sufficient flexibility. Conclusion: Results reveal that with experience, a competitive cyclist’s subjective and objective interpretation of their preselected saddle height becomes more consistent. Although hamstring extensibility does not appear to influence pre-selected saddle height, an initial 35˚ rather than 25˚ knee flexion angle is recommended. Future research should consider mixed methodologies, to further establish safe and effective recommendations for optimising bicycle fit. References Bini, R., Hume, P.A., & Croft, J.L. (2011). Effects of bicycle saddle height on knee injury risk and cycling performance. Sports Medicine, 41, 463-476. Ferrer-Roca, V., Roig, A., Galilea, P., & Garcia Lopez, J. (2012). Influence of saddle height on lower limb kinematics in well trained cyclists: static vs dynamic evaluation in bike fitting. Journal of Strength and Conditioning Research, 26, 3025- 3029. Muyor, J. M., Alacid, F., & Lopez-Minarro, P.A. (2011). Influence of hamstring muscles extensibility on spinal curvatures and pelvic tilt in highly trained cyclists. Journal of Human Kinetics, 29, 15-23

    Comparing the influence of ‘describing findings to the examiner’ or ‘examining as in usual practice’ on the students’ performance and assessors’ judgements during physical examination skills assessment

    Get PDF
    Background: Within assessment of physical examination skills, two approaches are common: “Describing Findings” (students comment throughout); and examining as “Usual Practice” (students only report findings at the end). Despite numerous potential influences on both students’ performances and assessors’ judgements, no prior studies have investigated the influence of either approach on assessments. Methods: Two group, randomised, crossover design. Within a 2-station simulated physical examination OSCE, we manipulated whether students “described findings” or examined as “usual practice”, collecting 1/. performance scores; 2/. Students’/examiners’ cognitive load ratings; ratings of the 3/. fluency and 4/. completeness of students’ presentations and 5/. Students’ task-finishing, comparing all 5 end-points across conditions. Results: Neither students’ performance scores nor examiners’ cognitive load were influenced by experimental condition. Students reported higher cognitive load (7/9) when “describing findings” than “usual practice” (6/9, p=0.002), and were less likely to finish (4 vs 12, p=0.007). Presentation completeness was higher for “describing findings” (mean=2.40, (95CIs=2.05-2.74)) than “usual practice” (mean=1.92 (1.65-2.18),p=0.016), whilst fluency ratings showed a similar trend. Conclusions: The decision to “Describe Findings” or examine as “Usual Practice” does not appear neutral, potentially influencing students’ efficiency, recall and (by inference) learning. Institutions should explicitly select one option based on assessment goals

    Pace of life, predators and parasites: predator-induced life-history evolution in Trinidadian guppies predicts decrease in parasite tolerance

    Get PDF
    A common evolutionary response to predation pressure is increased investment in reproduction, ultimately resulting in a fast life history. Theory and comparative studies suggest that short-lived organisms invest less in defence against parasites than those that are longer lived (the pace of life hypothesis). Combining these tenets of evolutionary theory leads to the specific, untested prediction that within species, populations experiencing higher predation pressure invest less in defence against parasites. The Trinidadian guppy, Poecilia reticulata, presents an excellent opportunity to test this prediction: guppy populations in lower courses of rivers experience higher predation pressure, and as a consequence have evolved faster life histories, than those in upper courses. Data from a large-scale field survey showed that fish infected with Gyrodactylus parasites were of a lower body condition (quantified using the scaled mass index) than uninfected fish, but only in lower course populations. Although the evidence we present is correlational, it suggests that upper course guppies sustain lower fitness costs of infection, i.e. are more tolerant, than lower course guppies. The data are therefore consistent with the pace of life hypothesis of parasite defence allocation, and suggest that life-history traits mediate the indirect effect of predators on the parasites of their prey

    A Model for the Analysis of Caries Occurrence in Primary Molar Tooth Surfaces

    Get PDF
    Recently methods of caries quantification in the primary dentition have moved away from summary ‘whole mouth’ measures at the individual level to methods based on generalised linear modelling (GLM) approaches or survival analysis approaches. However, GLM approaches based on logistic transformation fail to take into account the time-dependent process of tooth/surface survival to caries. There may also be practical difficulties associated with casting parametric survival-based approaches in a complex multilevel hierarchy and the selection of an optimal survival distribution, while non-parametric survival methods are not generally suitable for the assessment of supplementary information recorded on study participants. In the current investigation, a hybrid semi-parametric approach comprising elements of survival-based and GLM methodologies suitable for modelling of caries occurrence within fixed time periods is assessed, using an illustrative multilevel data set of caries occurrence in primary molars from a cohort study, with clustering of data assumed to occur at surface and tooth levels. Inferences of parameter significance were found to be consistent with previous parametric survival-based analyses of the same data set, with gender, socio-economic status, fluoridation status, tooth location, surface type and fluoridation status-surface type interaction significantly associated with caries occurrence. The appropriateness of the hierarchical structure facilitated by the hybrid approach was also confirmed. Hence the hybrid approach is proposed as a more appropriate alternative to primary caries modelling than non-parametric survival methods or other GLM-based models, and as a practical alternative to more rigorous survival-based methods unlikely to be fully accessible to most researchers

    Sexually transmitted infection risk exposure among black and minority ethnic youth in northwest London: findings from a study translating a sexually transmitted infection risk-reduction intervention to the UK setting.

    No full text
    OBJECTIVES: Young black women are disproportionately affected by sexually transmitted infections (STI) in the UK, but effective interventions to address this are lacking. The Young Brent Project explored the nature and context of sexual risk-taking in young people to inform the translation of an effective clinic-based STI reduction intervention (Project SAFE) from the USA to the UK. METHODS: One-to-one in-depth interviews (n = 37) and group discussions (n = 10) were conducted among men and women aged 15-27 years from different ethnic backgrounds recruited from youth and genitourinary medicine clinic settings in Brent, London. The interviews explored the context within which STI-related risks were assessed, experienced and avoided, the skills needed to recognise risk and the barriers to behaviour change. RESULTS: Concurrent sexual partnerships, mismatched perceptions and expectations, and barriers to condom use contributed to STI risk exposure and difficulties in implementing risk-reduction strategies. Women attempted to achieve monogamy, but experienced complex and fluid sexual relationships. Low risk awareness, flawed partner risk assessments, negative perceptions of condoms and lack of control hindered condom use. Whereas men made conscious decisions, women experienced persuasion, deceit and difficulty in requesting condom use, particularly with older partners. CONCLUSIONS: Knowledge of STI and condom use skills is not enough to equip young people with the means to reduce STI risk. Interventions with young women need to place greater emphasis on: entering and maintaining healthy relationships; awareness of risks attached to different forms of concurrency and how concurrency arises; skills to redress power imbalances and building self-esteem

    High-rate, high-fidelity entanglement of qubits across an elementary quantum network

    Full text link
    We demonstrate remote entanglement of trapped-ion qubits via a quantum-optical fiber link with fidelity and rate approaching those of local operations. Two 88{}^{88}Sr+{}^{+} qubits are entangled via the polarization degree of freedom of two photons which are coupled by high-numerical-aperture lenses into single-mode optical fibers and interfere on a beamsplitter. A novel geometry allows high-efficiency photon collection while maintaining unit fidelity for ion-photon entanglement. We generate remote Bell pairs with fidelity F=0.940(5)F=0.940(5) at an average rate 182s1182\,\mathrm{s}^{-1} (success probability 2.18×1042.18\times10^{-4}).Comment: v2 updated to include responses to reviewers, as published in PR
    corecore