6,316 research outputs found

    The Gamow-state description of the decay energy spectrum of neutron-unbound 25O

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    We show the feasibility of calculating the decay energy spectrum of neutron emitting nuclei within the Gamow-state description of resonances by obtaining the decay energy spectrum of 25O. We model this nucleus as a valence neutron interacting with an 24O inert core, and we obtain the resulting resonant energies, widths and decay energy spectra for the ground and first excited states. We also discuss the similarities and differences between the decay energy spectrum of a Gamow state and the Breit–Wigner distribution with energy-dependent width.Fil: Id Betan, Rodolfo Mohamed. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Rosario. Instituto de Física de Rosario. Universidad Nacional de Rosario. Instituto de Física de Rosario; ArgentinaFil: de la Madrid, Rafael. Lamar University; Estados Unido

    Cosmological tensor perturbations in theories beyond Lambda CDM

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    We study for the first time a complete analysis of the imprint of tensor anisotropies on the Cosmic Microwave Background for a class of f(R) gravity theories within the CAMB-PPF framework. Herein we present the most relevant equations, both for the cosmological background and gravitational wave perturbations, taking care to include all effects which arise from f(R) modifications. We find that that the dominant contribution to deviations from General Relativity in the temperature and polarization spectra can be attributed to modifications in the background. This demonstrates the importance of using the correct background in perturbative studies of f(R) gravity

    Sequentializing Parameterized Programs

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    We exhibit assertion-preserving (reachability preserving) transformations from parameterized concurrent shared-memory programs, under a k-round scheduling of processes, to sequential programs. The salient feature of the sequential program is that it tracks the local variables of only one thread at any point, and uses only O(k) copies of shared variables (it does not use extra counters, not even one counter to keep track of the number of threads). Sequentialization is achieved using the concept of a linear interface that captures the effect an unbounded block of processes have on the shared state in a k-round schedule. Our transformation utilizes linear interfaces to sequentialize the program, and to ensure the sequential program explores only reachable states and preserves local invariants.Comment: In Proceedings FIT 2012, arXiv:1207.348

    Iron(III)-catalyzed chlorination of activated arenes

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    A general and regioselective method for the chlorination of activated arenes has been developed. The transformation uses iron(III) triflimide as a powerful Lewis acid for the activation of N-chlorosuccinimide and the subsequent chlorination of a wide range of anisole, aniline, acetanilide and phenol derivatives. The reaction was utilized for the late-stage mono- and di-chlorination of a range of target compounds such as the natural product nitrofungin, the antibacterial agent chloroxylenol and the herbicide chloroxynil. The facile nature of this transformation was demonstrated with the development of one-pot tandem iron-catalyzed dihalogenation processes allowing highly regioselective formation of different carbon-halogen bonds. The synthetic utility of the resulting dihalogenated aryl compounds as building blocks was established with the synthesis of natural products and pharmaceutically relevant targets

    Covariant gauge-invariant perturbations in multifluid f(R) gravity

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    We study the evolution of scalar cosmological perturbations in the (1+3)- covariant gauge-invariant formalism for generic f(R)f(R) theories of gravity. Extending previous works, we give a complete set of equations describing the evolution of matter and curvature fluctuations for a multi-fluid cosmological medium. We then specialize to a radiation-dust fluid described by barotropic equations of state and solve the perturbation equations around a background solution of RnR^{n} gravity. In particular we study exact solutions for scales much smaller and much larger than the Hubble radius and show that n>2/3n>2/3 in order to have a growth rate compatible with the M\'esz\'aros effect.Comment: 32 pages, 3 figures, published versio

    A Novel Remaining Useful Estimation Model to Assist Asset Renewal Decisions Applied to the Brazilian Electric Sector

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    Assets deteriorate over time, as well as being covered, corroded, or becoming old in less obvious ways. Maintenance can extend the remaining useful life (RUL) of an asset system, but sooner or later it must surely be replaced. In this study, we propose a new RUL estimation methodology to assist in decision making for the maintenance and replacement of assets from prioritizing equipment in a renovation plan. Our methodology uses advanced data analysis techniques that consider multiple competing criteria with the goal of maximizing values of the asset throughout its life cycle, while considering the rules of remuneration and service quality of the current regulation, as well as the values at risk according to the decisions and actions taken. Experimental results with real datasets show the efficiency of the proposed approach. Finally, this work also presents the development of an analytical tool to optimize asset renewal decisions applying the RUL estimation methodology proposed and its application to the Brazilian electric sector

    Role of Bone Marrow Mesenchymal Stem Cells Concentrate Using Selective Retention Cell Technology in Posterolateral Spinal Fusion

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    IntroductionWith increasing rate of spinal fusion, the problem of pseudarthrosis which contributes to recurrent pain with patient disability is considered to be the most common cause of revision lu..

    Assessing the operational feasibility and acceptability of an inhalable formulation of oxytocin for improving community-based prevention of postpartum haemorrhage in Myanmar: a qualitative inquiry

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    Objective: This study assessed the potential operational feasibility and acceptability of a heat-stable, inhaled oxytocin (IOT) product for community-based prevention of postpartum haemorrhage in Myanmar. Methods: A qualitative inquiry was conducted between June 2015 and February 2016 through focus group discussions and in-depth interviews. Research was conducted in South Dagon township (urban setting) and in Ngape and Thanlyin townships (rural settings) in Myanmar. Eleven focus group discussions and 16 in-depth interviews were conducted with mothers, healthcare providers and other key informants. All audio recordings were transcribed verbatim in Myanmar language and were translated into English. Thematic content analysis was done using NVivo software. Results: Future introduction of an IOT product for community-based services was found to be acceptable among mothers and healthcare providers and would be feasible for use by lower cadres of healthcare providers, even in remote settings. Responses from healthcare providers and community members highlighted that midwives and volunteer auxiliary midwives would be key advocates for promoting community acceptance of the product. Healthcare providers perceived the ease of use and lack of dependence on cold storage as the main enablers for IOT compared with the current gold standard oxytocin injection. A single-use disposable device with clear pictorial instructions and a price that would be affordable by the poorest communities was suggested. Appropriate training was also said to be essential for the future induction of the product into community settings. Conclusion: In Myanmar, where home births are common, access to cold storage and skilled personnel who are able to deliver injectable oxytocin is limited. Among community members and healthcare providers, IOT was perceived to be an acceptable and feasible intervention for use by lower cadres of healthcare workers, and thus may be an alternative solution for the prevention of postpartum haemorrhage in community-based settings in the future

    Prevention of postpartum haemorrhage by community-based auxiliary midwives in hard-to-reach areas of Myanmar: a qualitative inquiry into acceptability and feasibility of task shifting

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    Background: In Myanmar, postpartum haemorrhage is the leading cause of maternal mortality and contributes to around 30% of all maternal deaths. The World Health Organization recommends training and supporting auxiliary midwives to administer oral misoprostol for prevention of postpartum haemorrhage in resource-limited settings. However, use of misoprostol by auxiliary midwives has not formally been approved in Myanmar. Our study aimed to explore community and provider perspectives on the roles of auxiliary midwives and community-level provision of oral misoprostol by auxiliary midwives. Methods: A qualitative inquiry was conducted in Ngape Township, Myanmar. A total of 15 focus group discussions with midwives, auxiliary midwives, community members and mothers with children under the age of three were conducted. Ten key informant interviews were performed with national, district and township level health planners and implementers of maternal and child health services. All audio recordings were transcribed verbatim in Myanmar language. Transcripts of focus group discussions were fully translated into English before coding, while key informants’ data were coded in Myanmar language. Thematic analysis was done using ATLAS.ti software. Results: Home births are common and auxiliary midwives were perceived as an essential care provider during childbirth in hard-to-reach areas. Main reasons provided were that auxiliary midwives are more accessible than midwives, live in the hard-to-reach areas, and are integrated in the community and well connected with midwives. Auxiliary midwives generally reported that their training involved instruction on active management of the third stage of labour, including use of misoprostol, but not all auxiliary midwives reported using misoprostol in practice. Supportive reasons for taskshifting administration of oral misoprostol to auxiliary midwives included discussions around the good relationship and trust between auxiliary midwives and midwives, whereby midwives felt confident distributing misoprostol to auxiliary midwives. However, the lack of clear government-level written permission to distribute the drug was perceived as a barrier to task shifting. Conclusion: This study highlights the acceptability of misoprostol use by auxiliary midwives to prevent postpartum haemorrhage, and findings suggest that it should be considered as a promising intervention for task shifting in Myanma
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