189 research outputs found

    Use of mixed methods designs in substance research: a methodological necessity in Nigeria

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    The utility of mixed methods (qualitative and quantitative) is becoming increasingly accepted in health sciences, but substance studies are yet to substantially benefit from such utilities. While there is a growing number of mixed methods alcohol articles concerning developed countries, developing nations are yet to embrace this method. In the Nigerian context, the importance of mixed methods research is yet to be acknowledged. This article therefore, draws on alcohol studies to argue that mixed methods designs will better equip scholars to understand, explore, describe and explain why alcohol consumption and its related problems are increasing in Nigeria. It argues that as motives for consuming alcohol in contemporary Nigeria are multiple, complex and evolving, mixed method approaches that provide multiple pathways for proffering solutions to problems should be embraced

    Simultaneous Extraction of the Fermi constant and PMNS matrix elements in the presence of a fourth generation

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    Several recent studies performed on constraints of a fourth generation of quarks and leptons suffer from the ad-hoc assumption that 3 x 3 unitarity holds for the first three generations in the neutrino sector. Only under this assumption one is able to determine the Fermi constant G_F from the muon lifetime measurement with the claimed precision of G_F = 1.16637 (1) x 10^-5 GeV^-2. We study how well G_F can be extracted within the framework of four generations from leptonic and radiative mu and tau decays, as well as from K_l3 decays and leptonic decays of charged pions, and we discuss the role of lepton universality tests in this context. We emphasize that constraints on a fourth generation from quark and lepton flavour observables and from electroweak precision observables can only be obtained in a consistent way if these three sectors are considered simultaneously. In the combined fit to leptonic and radiative mu and tau decays, K_l3 decays and leptonic decays of charged pions we find a p-value of 2.6% for the fourth generation matrix element |U_{e 4}|=0 of the neutrino mixing matrix.Comment: 19 pages, 3 figures with 16 subfigures, references and text added refering to earlier related work, figures and text in discussion section added, results and conclusions unchange

    Intensification of cattle ranching production systems: Socioeconomic and environmental synergies and risks in Brazil

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    Intensification of Brazilian cattle ranching systems has attracted both national and international attention due to its direct relation with Amazon deforestation on the one hand and increasing demand of the global population for meat on the other. Since Brazilian cattle ranching is predominantly pasture-based, we particularly focus on pasture management. We summarize the most recurrent opportunities and risks associated with pasture intensification that are brought up within scientific and political dialogues, and discuss them within the Brazilian context. We argue that sustainable intensification of pasturelands in Brazil is a viable way to increase agricultural output while simultaneously sparing land for nature. Since environmental degradation is often associated with low-yield extensive systems in Brazil, it is possible to obtain higher yields, while reversing degradation, by adopting practices like rotational grazing, incorporation of legumes and integrated crop-livestock-forestry systems. Technical assistance is however essential, particularly for small- and medium-scale farmers. Sound complementary policies and good governance must accompany these measures so that a ‘rebound effect’ does not lead to increased deforestation and other adverse social and environmental impacts. It is also important that animal welfare is not compromised. Although the discussion is presented with respect to Brazil, some aspects are relevant to other developing countries

    Meaningful time for professional growth or a waste of time? A study in five countries on teachers’ experiences within master’s dissertation/thesis work

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    The relationship between master’s thesis work and teachers’ professional development has rarely been explored empirically, yet. Drawing upon a larger study, this paper investigates how teachers who were studying for or who have recently graduated from Master of Education programmes offered in five countries – Poland, Portugal, England, Latvia, Romania – perceive the usefulness of dissertation/thesis work for their professional development and how they attempt to use their MA research results in their (future) teaching practice. Results suggest that although most respondents recognized their MA dissertation/thesis work as having a positive impact on their professional development by enhancing their professionalism, personal development and growth, and understanding the relationship between research and practice, they were less confident about the use of MA research findings in their (future) workplaces. These results are discussed in the context of current challenges regarding master’s level education for teachers, national governments’ educational policies, and the relationship between research, teachers’ practices and professional development

    Status of the X17 search in Montreal

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    At the Montreal Tandem accelerator, an experiment is being set up to measure internal pair creation from the decay of nuclear excited states using a multiwire proportional chamber and scintillator bars surrounding it from the DAPHNE experiment. The acceptance covers a solid angle of nearly 4π\pi. Preamplifiers and the data acquisition hardware have been designed and tested. The water-cooled 7^7LiF target, mounted on an Al foil is in a thin carbon fiber section of the beamline. The experiment will focus at first on a measurement of the internal pair creation from the 18.15 MeV state of 8^8Be. Assuming the ATOMKI evaluation of the electron-pair production rate from X17, a Geant4 simulation predicts observation of a clear signal after about two weeks of data taking with a 2 μ\muA proton beam. The IPC measurement could eventually be extended to the giant dipole resonance of 8^8Be, as well as to other nuclei, in particular to 10^{10}B.Comment: 5 pages, 4 figures, Proceedings contribution, TRIUMF Ariel Workshop, May 25-27 202

    Improved measurement of the K+->pi+nu(nu)over-bar branching ratio

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    An additional event near the upper kinematic limit for K+-->pi(+)nu(nu) over bar has been observed by experiment E949 at Brookhaven National Laboratory. Combining previously reported and new data, the branching ratio is B(K+-->pi(+)nu(nu) over bar)=(1.47(-0.89)(+1.30))x10(-10) based on three events observed in the pion momentum region 211<P<229 MeV/c. At the measured central value of the branching ratio, the additional event had a signal-to-background ratio of 0.9

    Experiences with community engagement and informed consent in a genetic cohort study of severe childhood diseases in Kenya

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    <p>Abstract</p> <p>Background</p> <p>The potential contribution of community engagement to addressing ethical challenges for international biomedical research is well described, but there is relatively little documented experience of community engagement to inform its development in practice. This paper draws on experiences around community engagement and informed consent during a genetic cohort study in Kenya to contribute to understanding the strengths and challenges of community engagement in supporting ethical research practice, focusing on issues of communication, the role of field workers in 'doing ethics' on the ground and the challenges of community consultation.</p> <p>Methods</p> <p>The findings are based on action research methods, including analysis of community engagement documentation and the observations of the authors closely involved in their development and implementation. Qualitative and quantitative content analysis has been used for documentation of staff meetings and trainings, a meeting with 24 community leaders, and 40 large public and 70 small community group meetings. Meeting minutes from a purposive sample of six community representative groups have been analysed using a thematic framework approach.</p> <p>Results</p> <p>Field workers described challenges around misunderstandings about research, perceived pressure for recruitment and challenges in explaining the study. During consultation, leaders expressed support for the study and screening for sickle cell disease. In community meetings, there was a common interpretation of research as medical care. Concerns centred on unfamiliar procedures. After explanations of study procedures to leaders and community members, few questions were asked about export of samples or the archiving of samples for future research.</p> <p>Conclusions</p> <p>Community engagement enabled researchers to take account of staff and community opinions and issues during the study and adapt messages and methods to address emerging ethical challenges. Field workers conducting informed consent faced complex issues and their understanding, attitudes and communication skills were key influences on ethical practice. Community consultation was a challenging concept to put into practice, illustrating the complexity of assessing information needs and levels of deliberation that are appropriate to a given study.</p

    Mixing of Active and Sterile Neutrinos

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    We investigate mixing of neutrinos in the ν\nuMSM (neutrino Minimal Standard Model), which is the MSM extended by three right-handed neutrinos. Especially, we study elements of the mixing matrix ΘαI\Theta_{\alpha I} between three left-handed neutrinos να\nu_\alpha (α=e,μ,τ\alpha = e,\mu,\tau) and two sterile neutrinos NIN_I (I=2,3I=2,3) which are responsible to the seesaw mechanism generating the suppressed masses of active neutrinos as well as the generation of the baryon asymmetry of the universe (BAU). It is shown that ΘeI\Theta_{eI} can be suppressed by many orders of magnitude compared with ΘμI\Theta_{\mu I} and ΘτI\Theta_{\tau I}, when the Chooz angle θ13\theta_{13} is large in the normal hierarchy of active neutrino masses. We then discuss the neutrinoless double beta decay in this framework by taking into account the contributions not only from active neutrinos but also from all the three sterile neutrinos. It is shown that N2N_2 and N3N_3 give substantial, destructive contributions when their masses are smaller than a few 100 MeV, and as a results ΘeI\Theta_{e I} receive no stringent constraint from the current bounds on such decay. Finally, we discuss the impacts of the obtained results on the direct searches of N2,3N_{2,3} in meson decays for the case when N2,3N_{2,3} are lighter than pion mass. We show that there exists the allowed region for N2,3N_{2,3} with such small masses in the normal hierarchy case even if the current bound on the lifetimes of N2,3N_{2,3} from the big bang nucleosynthesis is imposed. It is also pointed out that the direct search by using π+→e++N2,3\pi^+ \to e^+ + N_{2,3} and K+→e++N2,3K^+ \to e^+ + N_{2,3} might miss such N2,3N_{2,3} since the branching ratios can be extremely small due to the cancellation in ΘeI\Theta_{eI}, but the search by K+→μ++N2,3K^+ \to \mu^+ + N_{2,3} can cover the whole allowed region by improving the measurement of the branching ratio by a factor of 5.Comment: 30 pages, 32 figure
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