127 research outputs found

    Fermilab E791

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    Fermilab E791, a very high statistics charm particle experiment, recently completed its data taking at Fermilab's Tagged Photon Laboratory. Over 20 billion events were recorded through a loose transverse energy trigger and written to 8mm tape in the the 1991-92 fixed target run at Fermilab. This unprecedented data sample containing charm is being analysed on many-thousand MIP RISC computing farms set up at sites in the collaboration. A glimpse of the data taking and analysis effort is presented. We also show some preliminary results for common charm decay modes. Our present analysis indicates a very rich yield of over 200K reconstructed charm decays.Comment: 4 pages, 1 figure, LaTe

    Dalitz Plot Analysis of the Decay D^+ --> K^- pi^+ pi^+ and Indication of a Low-Mass Scalar K pi Resonance

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    We study the Dalitz plot of the decay D^+ --> K^- pi^+ pi^+ with a sample of 15090 events from Fermilab experiment E791. Modeling the decay amplitude as the coherent sum of known K pi resonances and a uniform nonresonant term, we do not obtain an acceptable fit. If we allow the mass and width of the K^*_0(1430) to float, we obtain values consistent with those from PDG but the chi^2 per degree of freedom of the fit is still unsatisfactory. A good fit is found when we allow for the presence of an additional scalar resonance, with mass 797 +/- 19 +/- 43 MeV/c^2 and width 410 +/- 43 +/- 87 MeV/c^2. The mass and width of the K^*_0(1430) become 1459 +/- 7 +/- 5 MeV/c^2 and 175 +/- 12 +/- 12 MeV/c^2, respectively. Our results provide new information on the scalar sector in hadron spectroscopy.Comment: Accepted for publication in Physical Review Letter

    Recovery and resilience of tropical forests after disturbance

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    The time taken for forested tropical ecosystems to re-establish post-disturbance is of widespread interest. Yet to date there has been no comparative study across tropical biomes to determine rates of forest re-growth, and how they vary through space and time. Here we present results from a meta-analysis of palaeoecological records that use fossil pollen as a proxy for vegetation change over the past 20,000 years. A total of 283 forest disturbance and recovery events, reported in 71 studies, are identified across four tropical regions. Results indicate that forests in Central America and Africa generally recover faster from past disturbances than those in South America and Asia, as do forests exposed to natural large infrequent disturbances compared with post-climatic and human impacts. Results also demonstrate that increasing frequency of disturbance events at a site through time elevates recovery rates, indicating a degree of resilience in forests exposed to recurrent past disturbance

    Healthcare providers’ perspectives of disrespect and abuse in maternity care facilities in Nigeria: a qualitative study

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    Objectives To explore healthcare providers’ perspectives of disrespect and abuse in maternity care and the impact on women’s health and well-being. Methods Qualitative interpretive approach using in-depth semi-structured interviews with sixteen healthcare providers in two public health facilities in Nigeria. Interviews were audio-recorded, transcribed, and analysed thematically. Results Healthcare providers’ accounts revealed awareness of what respectful maternity care encompassed in accordance with the existing guidelines. They considered disrespectful and abusive practices perpetrated or witnessed as violation of human rights, while highlighting women’s expectations of care as the basis for subjectivity of experiences. They perceived some practices as well-intended to ensure safety of mother and baby. Views reflected underlying gender-related notions and societal perceptions of women being considered weaker than men. There was recognition about adverse effects of disrespect and abuse including its impact on women, babies, and providers’ job satisfaction. Conclusions Healthcare providers need training on how to incorporate elements of respectful maternity care into practice including skills for rapport building and counselling. Women and family members should be educated about right to respectful care empowering them to report disrespectful practices
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