1,426 research outputs found

    Semileptonic decays of baryons in a relativistic quark model

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    We calculate semileptonic decays of light and heavy baryons in a relativistically covariant constituent quark model. The model is based on the Bethe-Salpeter-equation in instantaneous approximation. It generates satisfactory mass spectra for mesons and baryons up to the highest observable energies. Without introducing additional free parameters we compute on this basis helicity amplitudes of electronic and muonic semileptonic decays of baryons. We thus obtain form factor ratios and decay rates in good agreement with experiment.Comment: 8 pages, 10 figures, 2 tables, typos remove

    Weighing simulated galaxy clusters using lensing and X-ray

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    We aim at investigating potential biases in lensing and X-ray methods to measure the cluster mass profiles. We do so by performing realistic simulations of lensing and X-ray observations that are subsequently analyzed using observational techniques. The resulting mass estimates are compared among them and with the input models. Three clusters obtained from state-of-the-art hydrodynamical simulations, each of which has been projected along three independent lines-of-sight, are used for this analysis. We find that strong lensing models can be trusted over a limited region around the cluster core. Extrapolating the strong lensing mass models to outside the Einstein ring can lead to significant biases in the mass estimates, if the BCG is not modeled properly for example. Weak lensing mass measurements can be largely affected by substructures, depending on the method implemented to convert the shear into a mass estimate. Using non-parametric methods which combine weak and strong lensing data, the projected masses within R200 can be constrained with a precision of ~10%. De-projection of lensing masses increases the scatter around the true masses by more than a factor of two due to cluster triaxiality. X-ray mass measurements have much smaller scatter (about a factor of two smaller than the lensing masses) but they are generally biased low by 5-20%. This bias is ascribable to bulk motions in the gas of our simulated clusters. Using the lensing and the X-ray masses as proxies for the true and the hydrostatic equilibrium masses of the simulated clusters and averaging over the cluster sample we are able to measure the lack of hydrostatic equilibrium in the systems we have investigated.Comment: 27 pages, 21 figures, accepted for publication on A&A. Version with full resolution images can be found at http://pico.bo.astro.it/~massimo/Public/Papers/massComp.pd

    Reproductive governance in a fragile and population-dense context: family planning policies, discourses, and practices in Burundi

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    This article describes the reproductive governance deployed in Burundi, which promotes fertility control through uptake of modern contraceptives as a solution to the economic hardship and land pressure of individuals and communities. Using a qualitative approach, we explore how women and couples in rural Burundi set their preferences, choices and practices of family planning, and how they relate with the government discourse. We describe how reproductive practices are complex and modulated by social and material factors and power dynamics. We argue that the current hegemonic discourse-largely supported by external donors-adopts a depoliticised and technocratic approach to family planning that aligns with neoliberal development frameworks, leaving existing power dynamics and resources distribution issues unexamined and unaddressed. By situating reproductive navigation in context, we show how medicalisation of reproduction is not fully enacted, and partly resisted by women and other actors

    Environmental Response Management Application

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    The Coastal Response Research Center (CRRC), a partnership between the University of New Hampshire (UNH) and NOAA\u27s Office of Response and Restoration (ORR), is leading an effort to develop a data platform capable of interfacing both static and real-time data sets accessible simultaneously to a command post and assets in the field with an open source internet mapping server. The Environmental Response Management Application (ERMA™) is designed to give responders and decision makers ready access to geographically specific data useful during spill planning/drills, incident response, damage assessment and site restoration. In addition to oil spill and chemical release response, this website can be relevant to other environmental incidents and natural disasters, responses and regional planning efforts. The platform is easy to operate, without the assistance of Information Technology or Geographic Information Systems (GIS) specialists. It allows users to access individual data layer values, overlay relevant data sets, and zoom into segments of interest. The platform prototype is being developed specifically for Portsmouth Harbor and the Great Bay Estuary, NH. The prototype demonstrates the capabilities of an integrated data management platform and serves as the pilot for web-based GIS platforms in other regions

    Differential Spectral Imaging of the CN Violet Band in Laser-Induced Plasmas on TNT Simulant Molecules

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    Dual channel emission imaging of m-nitrobenzoic acid and benzoic acid was performed in order to visualize the morphology of the CN violet band emission of a TNT analogue. The CN channel was corrected for continuum emission using a simultaneously imaged background channel. Simultaneous dual channel imaging alleviated problems with shot to shot variation in the plasma morphology due to the friable substrates and showed differences between plasmas formed on the two targets

    A role for ultrasonic vocalisation in social communication and divergence of natural populations of the house mouse (Mus musculus domesticus)

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    It has long been known that rodents emit signals in the ultrasonic range, but their role in social communication and mating is still under active exploration. While inbred strains of house mice have emerged as a favourite model to study ultrasonic vocalisation (USV) patterns, studies in wild animals and natural situations are still rare. We focus here on two wild derived mouse populations. We recorded them in dyadic encounters for extended periods of time to assess possible roles of USVs and their divergence between allopatric populations. We have analysed song frequency and duration, as well as spectral features of songs and syllables. We show that the populations have indeed diverged in several of these aspects and that USV patterns emitted in a mating context differ from those emitted in same sex encounters. We find that females vocalize not less, in encounters with another female even more than males. This implies that the current focus of USVs being emitted mainly by males within the mating context needs to be reconsidered. Using a statistical syntax analysis we find complex temporal sequencing patterns that could suggest that the syntax conveys meaningful information to the receivers. We conclude that wild mice use USV for complex social interactions and that USV patterns can diverge fast between populations

    Barriers to family planning use in the Eastern Democratic Republic of the Congo: an application of the theory of planned behaviour using a longitudinal survey

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    OBJECTIVE: In the Democratic Republic of the Congo, there is a low adherence of the population to the use of family planning (FP) due to various social barriers. This study aimed to understand the drives from social barriers to the use of FP in women in the Kivu, a region particularly affected by poverty and many years of conflicts. A theory of planned behaviour (TPB) using a generalised structural equation modelling has been applied to understand the complex sociocultural drivers to the intention and the ultimate decision to use FP. DESIGN: Longitudinal study. SETTING: A community-based approach was used to investigate FP use in the North and South-Kivu regions. PARTICIPANTS: Overall, 1812 women 15 years and older were enrolled in the baseline study and 1055 were retrieved during the follow-up. PRIMARY AND SECONDARY OUTCOMES: FP use and intention to use FP. RESULTS: The mean age was 36+/-12.9 years, with a minimum of 15 years old and a maximum of 94 years old. Among sexually active participants, more than 40% used a modern contraceptive method at the last sexual intercourse. Education was positively and significantly associated with intention to use FP (beta=0.367; p=0.008). Being married was positively and marginally significantly associated with intention to use FP (beta=0.524: p=0.050). Subjective norms were negatively and significantly associated with intention to use FP (beta=-0.572; p=0.003) while perceived control was positively associated with intention to use FP (beta=0.578; p<0.0001). Education and perceived control were positively and significantly associated with the use of FP (respectively, beta=0.422, p=0.017; and beta=0.374; p=0.017), while Intention to use FP was positively and marginally significantly associated with the use of FP (beta=0.583; p=0.052). CONCLUSION: TPB helped understand sociocultural barriers to FP use and it can be useful to define adapted strategies in different contexts

    Evidence of health system resilience in Myanmar during cyclone Nargis: a qualitative analysis

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    OBJECTIVE: The aim of this study is to improve the understanding of the characteristics of health system resilience in Myanmar's response to Cyclone Nargis and to explore ways to improve resilience at the system level. DESIGN AND SETTING: This is an explanatory qualitative study exploring the institutional capacity of resilience in Myanmar's health system. Analysis proceeded using a data-driven thematic analysis closely following the framework method. This process enabled comparisons and contrasts of key emergent themes between the participants, which later generated key results describing the foundational assets, barriers and opportunities for achieving resilience in Myanmar. PARTICIPANTS: The study comprised of 12 in-depth interviews conducted with representatives from international organisations and non-governmental organisations (NGOs). The inclusion criteria to recruiting the participants were that they had directly been a part of the Cyclone Nargis response at the time. There was a balanced distribution of participants across UN, bilateral and NGOs, and most of them were either Myanmar citizens or expatriates with extensive working experience based in Myanmar. RESULTS: Key findings elucidate the characteristics of resilience that have been salient or absent in Myanmar's response to Cyclone Nargis. Strong social capital and motivation propelled by its deep-rooted culture and religion served as Myanmar's greatest assets that filled major gaps in the system. Meanwhile, its postcolonial and military legacy posed barriers towards investing in building its long-term foundations towards resilience. CONCLUSIONS: This study revealed that resilience in the health system can be built through strategic investments towards building the foundations of resilience to better prepare for future shocks. In the case of Myanmar, social capital and motivation, which surfaced as its foundational assets, can be channelled into opportunities that can help achieve its long-term health goals, accelerating its journey towards resilience in the health system

    Electromagnetic properties of strange baryons in a relativistic quark model

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    We present some of our results for the electromagnetic properties of excited ÎŁ hyperons, computed within the framework of the Bonn constituent-quark model, which is based on the Bethe-Salpeter approach. The seven parameters entering the model are fitted against the best-known baryon masses. Accordingly, the results for the form factors and helicity amplitudes are genuine predictions. We compare with the scarce experimental data available and discuss the processes in which ÎŁ *'s may play an important role

    Thermo-tectonic evolution of a convergent orogen with low topographic build-up: Exhumation and kinematic patterns in the Romanian Carpathians derived from thermochronology

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    Andriessen, P.A.M. [Promotor]Matenco, L.C. [Copromotor
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