24 research outputs found

    Measurement of flavor asymmetry of light-quark sea in the proton with Drell-Yan dimuon production in p+pp+p and p+dp+d collisions at 120 GeV

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    Evidence for a flavor asymmetry between the uĖ‰\bar u and dĖ‰\bar d quark distributions in the proton has been found in deep-inelastic scattering and Drell-Yan experiments. The pronounced dependence of this flavor asymmetry on xx (fraction of nucleon momentum carried by partons) observed in the Fermilab E866 Drell-Yan experiment suggested a drop of the dĖ‰(x)/uĖ‰(x)\bar d\left(x\right) / \bar u\left(x\right) ratio in the x>0.15x > 0.15 region. We report results from the SeaQuest Fermilab E906 experiment with improved statistical precision for dĖ‰(x)/uĖ‰(x)\bar d\left(x\right) / \bar u\left(x\right) in the large xx region up to x=0.45x=0.45 using the 120 GeV proton beam. Two different methods for extracting the Drell-Yan cross section ratios, Ļƒpd/2Ļƒpp\sigma^{pd} /2 \sigma^{pp}, from the SeaQuest data give consistent results. The dĖ‰(x)/uĖ‰(x)\bar{d}\left(x\right) / \bar{u}\left(x\right) ratios and the dĖ‰(x)āˆ’uĖ‰(x)\bar d\left(x\right) - \bar u\left(x\right) differences are deduced from these cross section ratios for 0.13<x<0.450.13 < x < 0.45. The SeaQuest and E866/NuSea dĖ‰(x)/uĖ‰(x)\bar{d}\left(x\right) / \bar{u}\left(x\right) ratios are in good agreement for the xā‰²0.25x\lesssim 0.25 region. The new SeaQuest data, however, show that dĖ‰(x)\bar d\left(x\right) continues to be greater than uĖ‰(x)\bar u\left(x\right) up to the highest xx value (x=0.45x = 0.45). The new results on dĖ‰(x)/uĖ‰(x)\bar{d}\left(x\right) / \bar{u}\left(x\right) and dĖ‰(x)āˆ’uĖ‰(x)\bar{d}\left(x\right) - \bar{u}\left(x\right) are compared with various parton distribution functions and theoretical calculations

    The accessibility and acceptability of self-management support interventions for men with long term conditions: a systematic review and meta-synthesis of qualitative studies

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    Background: Self-management support interventions can improve health outcomes, but their impact is limited by the numbers of people able or willing to access them. Menā€™s attendance at existing self-management support services appears suboptimal despite their increased risk of developing many of the most serious long term conditions. The aim of this review was to determine whether current self-management support interventions are acceptable and accessible to men with long term conditions, and explore what may act as facilitators and barriers to access of interventions and support activities. Methods: A systematic search for qualitative research was undertaken on CINAHL, EMBASE, MEDLINE, PsycINFO and Social Science Citation Index, in July 2013. Reference lists of relevant articles were also examined. Studies that used a qualitative design to explore menā€™s experiences of, or perceptions towards, self-management support for one or more long term condition were included. Studies which focused on experiences of living with a long term condition without consideration of self-management support were excluded. Thirty-eight studies met the inclusion criteria. A meta-ethnography approach was employed to synthesise the findings. Results: Four constructs associated with menā€™s experience of, and perceptions towards, self management support were identified: 1) need for purpose; 2) trusted environments; 3) value of peers; and 4) becoming an expert. The synthesis showed that men may feel less comfortable participating in self-management support if it is viewed as incongruous with valued aspects of their identity, particularly when activities are perceived to challenge masculine ideals associated with independence, stoicism, and control. Men may find self-management support more attractive when it is perceived as action-oriented, having a clear purpose, and offering personally meaningful information and practical strategies that can be integrated into daily life. Conclusions: Self-management support is most likely to be successful in engaging men when it is congruent with key aspects of their masculine identity. In order to overcome barriers to access and fully engage with interventions, some men may need self-management support interventions to be delivered in an environment that offers a sense of shared understanding, connectedness, and normality, and involves and/or is facilitated by men with a shared illness experience

    Micro-fabricated stylus ion trap

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    An electroformed, three-dimensional stylus Paul trap was designed to confine a single atomic ion for use as a sensor to probe the electric-field noise of proximate surfaces. The trap was microfabricated with the UV-LIGA technique to reduce the distance of the ion from the surface of interest. We detail the fabrication process used to produce a 150 Ī¼m tall stylus trap with feature sizes of 40ā€‰Ī¼m. We confined single, laser-cooled, 25Mg+ ions with lifetimes greater than 2 h above the stylus trap in an ultra-high-vacuum environment. After cooling a motional mode of the ion at 4 MHz close to its ground state (āŸØnāŸ© = 0.34 Ā± 0.07), the heating rate of the trap was measured with Raman sideband spectroscopy to be 387 Ā± 15 quanta/s at an ion height of 62 Ī¼m above the stylus electrodes
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