1,921 research outputs found

    Importance of strategic management in the implementation of private medicine retailer programmes: case studies from three districts in Kenya

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    BACKGROUND: The home-management of malaria strategy seeks to improve prompt and effective anti-malarial drug use through the informal sector, with a potential channel being the Private Medicine Retailers (PMRs). Previous evaluations of PMR programmes focused on their impact on retailer knowledge and practices, with limited evidence about the influence of implementation processes on the impacts at scale. This paper examines how the implementation processes of three PMR programmes in Kenya, each scaled up within a district, contributed to the outcomes observed. These were a Ministry of Health programme in Kwale district; and two programmes supported by non-governmental organizations in collaboration with government in Kisii Central and Bungoma districts. METHODS: The research methods included 24 focus group discussions with clients and PMRs, 19 in-depth interviews with implementing actors, document review and a diary of events. The data were analysed using the combination of a broad policy analysis framework and more specific scaling up/diffusion of innovations frameworks. RESULTS: The Kisii programme, a case study of successful implementation, was underpinned by good relationships between district health managers and a "resource team", supported by a memorandum of understanding which enabled successful implementation. It had flexible budgetary and decision making processes which were responsive to local contexts, and took account of local socio-economic activities. In contrast, the Kwale programme, which had implementation challenges, was characterised by a complex funding process, with lengthy timelines, that was tied to the government financial management system which constrained implementation Although there was a flexible funding system in Bungoma, a perceived lack of transparency in fund management, inadequate management of inter-organisational relationships, and inability to adapt and respond to changing circumstances led to implementation difficulties. CONCLUSIONS: For effective scaling up of PMR programmes, the provision of technical support and adequate resources are vital, but not sufficient on their own. An active strategy to manage relationships between implementing actors through effective communication mechanisms is essential. Successful outcomes may be realised if a strong and transparent management system, including management of financial resources, is put in place. This study provides evidence of the value of assessing implementation processes as part of impact evaluation for public health programmes

    Dynamical Boson Stars

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    The idea of stable, localized bundles of energy has strong appeal as a model for particles. In the 1950s John Wheeler envisioned such bundles as smooth configurations of electromagnetic energy that he called {\em geons}, but none were found. Instead, particle-like solutions were found in the late 1960s with the addition of a scalar field, and these were given the name {\em boson stars}. Since then, boson stars find use in a wide variety of models as sources of dark matter, as black hole mimickers, in simple models of binary systems, and as a tool in finding black holes in higher dimensions with only a single killing vector. We discuss important varieties of boson stars, their dynamic properties, and some of their uses, concentrating on recent efforts.Comment: 79 pages, 25 figures, invited review for Living Reviews in Relativity; major revision in 201

    Gravitational Waves from Gravitational Collapse

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    Gravitational wave emission from the gravitational collapse of massive stars has been studied for more than three decades. Current state of the art numerical investigations of collapse include those that use progenitors with realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non--axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with advanced ground--based and future space--based interferometric observatories.Comment: 68 pages including 13 figures; revised version accepted for publication in Living Reviews in Relativity (http://www.livingreviews.org

    Seismic site characterization of the Kastelli (Kissamos) Basin in northwest Crete (Greece): Assessments using ambient noise recordings

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    Crete is actively seismic and site response studies are needed for estimating local site conditions subjected to seismic activity. In order to collect basic data, we performed ambient noise recordings to estimate the site response of the surface and near subsurface structure of the small-scale Kastelli Basin in northwest Crete. The spatial horizontal to vertical spectral ratios (HVSR) resonance pattern of the investigated sites in the centre of the Basin consists of either one or two peaks divided into low to high frequency range in different sites as follows: (a) in some sites only one amplified peak at low frequencies (0.6–1.2 Hz), (b) in other sites only one amplified peak at medium frequencies (2.9–8.5 Hz) and (c) in yet other sites two amplified peaks in the low to high frequency range (0.6–15.5 Hz). The investigated sites are amplified in the frequency range 0.6–15.5 Hz, while the amplitude reaches to a factor of 4 in the spectral ratios. The one HVSR amplified peak at low frequencies is related to locally soft or thick Quaternary deposits. Microtremors were measured in the coastal northwest part of the Basin in a well—lithified Cretaceous limestone site characterized by fractures and faults striking predominantly in a sector NNE to NNW. Sites of one amplified peak at medium frequencies are extended from coastal northwest to southwest delineating a structure striking to NNW. The two amplified peaks are attributed to shallow subsurface heterogeneities/irregularities, locally induced by fault zones and to the overlying Quaternary deposits. Spatial HVSR variations in the frequency and HVSR shape delineate four structures striking NNE, NNW and in a sector NW to WNW, crosscutting the dense populated Basin suggesting that microtremors could be a valuable tool for providing a first approximation of fault zone delineation at least for the Kastelli-Kissamos Basin. The Basin is classified into the X soil category of the Greek Seismic Code 2000.This work was implemented through the project entitled “Interdisciplinary Multi-Scale Research of Earth-quake Physics and Seismotectonics at the Front of the Hellenic Arc (IMPACT-ARC)” in the framework of action “ARCHIMEDES III—Support of Research Teams at TEI of Crete” (MIS380353) of the Operational Program “Education and Lifelong Learning” and is co-financed by the European Union (European Social Fund) and Greek national fund

    Search for a Technicolor omega_T Particle in Events with a Photon and a b-quark Jet at CDF

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    If the Technicolor omega_T particle exists, a likely decay mode is omega_T -> gamma pi_T, followed by pi_T -> bb-bar, yielding the signature gamma bb-bar. We have searched 85 pb^-1 of data collected by the CDF experiment at the Fermilab Tevatron for events with a photon and two jets, where one of the jets must contain a secondary vertex implying the presence of a b quark. We find no excess of events above standard model expectations. We express the result of an exclusion region in the M_omega_T - M_pi_T mass plane.Comment: 14 pages, 2 figures. Available from the CDF server (PS with figs): http://www-cdf.fnal.gov/physics/pub98/cdf4674_omega_t_prl_4.ps FERMILAB-PUB-98/321-

    Studying the Underlying Event in Drell-Yan and High Transverse Momentum Jet Production at the Tevatron

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    We study the underlying event in proton-antiproton collisions by examining the behavior of charged particles (transverse momentum pT > 0.5 GeV/c, pseudorapidity |\eta| < 1) produced in association with large transverse momentum jets (~2.2 fb-1) or with Drell-Yan lepton-pairs (~2.7 fb-1) in the Z-boson mass region (70 < M(pair) < 110 GeV/c2) as measured by CDF at 1.96 TeV center-of-mass energy. We use the direction of the lepton-pair (in Drell-Yan production) or the leading jet (in high-pT jet production) in each event to define three regions of \eta-\phi space; toward, away, and transverse, where \phi is the azimuthal scattering angle. For Drell-Yan production (excluding the leptons) both the toward and transverse regions are very sensitive to the underlying event. In high-pT jet production the transverse region is very sensitive to the underlying event and is separated into a MAX and MIN transverse region, which helps separate the hard component (initial and final-state radiation) from the beam-beam remnant and multiple parton interaction components of the scattering. The data are corrected to the particle level to remove detector effects and are then compared with several QCD Monte-Carlo models. The goal of this analysis is to provide data that can be used to test and improve the QCD Monte-Carlo models of the underlying event that are used to simulate hadron-hadron collisions.Comment: Submitted to Phys.Rev.

    Measurement of the Dipion Mass Spectrum in X(3872) -> J/Psi Pi+ Pi- Decays

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    We measure the dipion mass spectrum in X(3872)--> J/Psi Pi+ Pi- decays using 360 pb-1 of pbar-p collisions at 1.96 TeV collected with the CDF II detector. The spectrum is fit with predictions for odd C-parity (3S1, 1P1, and 3DJ) charmonia decaying to J/Psi Pi+ Pi-, as well as even C-parity states in which the pions are from Rho0 decay. The latter case also encompasses exotic interpretations, such as a D0-D*0Bar molecule. Only the 3S1 and J/Psi Rho hypotheses are compatible with our data. Since 3S1 is untenable on other grounds, decay via J/Psi Rho is favored, which implies C=+1 for the X(3872). Models for different J/Psi-Rho angular momenta L are considered. Flexibility in the models, especially the introduction of Rho-Omega interference, enable good descriptions of our data for both L=0 and 1.Comment: 7 pages, 4 figures -- Submitted to Phys. Rev. Let

    Measurement of Lifetime and Decay-Width Difference in B0s -> J/psi phi Decays

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    We measure the mean lifetime, tau=2/(Gamma_L+Gamma_H), and the width difference, DeltaGamma=Gamma_L-Gamma_H, of the light and heavy mass eigenstates of the B0s meson, B0sL and B0sH, in B0s -> J/psi phi decays using 1.7 fb^-1 of data collected with the CDF II detector at the Fermilab Tevatron ppbar collider. Assuming CP conservation, a good approximation for the B0s system in the Standard Model, we obtain DeltaGamma = 0.076^+0.059_-0.063 (stat.) +- 0.006 (syst.) ps^-1 and tau = 1.52 +- 0.04 (stat.) +- 0.02 (syst.) ps, the most precise measurements to date. Our constraints on the weak phase and DeltaGamma are consistent with CP conservation. Dedicated to the memory of our dear friend and colleague, Michael P. Schmid

    Measurement of the Top-Quark Mass in All-Hadronic Decays in p pbar Collisions at CDF II

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    We present a measurement of the top-quark mass, MtopM_{\mathrm{top}}, in the all-hadronic decay channel ttˉW+bWbˉq1qˉ2bq3qˉ4bˉt\bar{t} \to W^+b W^- \bar{b} \to q_1\bar{q}_2 b q_3 \bar{q}_4 \bar{b}. The analysis is performed using 310 pb1^{-1} of s\sqrt{s}=1.96 TeV ppˉp\bar{p} collisions collected with the CDF II detector using a multi-jet trigger. The mass measurement is based on an event-by-event likelihood which depends on both the sample purity and the value of the top-quark mass, using 90 possible jet-to-parton assignments in the six-jet final state. The joint likelihood of 290 selected events yields a value of MtopM_{\mathrm{top}}=177.1 ±\pm 4.9 (stat.) ±\pm 4.7 (syst.) GeV/c2c^2.Comment: 7 pages, 2 figures and 1 table, Submitted to Phys. Rev. Let

    Observation of WZ Production

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    We report the first observation of the associated production of a W boson and a Z boson. This result is based on 1.1 fb-1 of integrated luminosity from ppbar collisions at sqrt{s} = 1.96 TeV collected with the CDF II detector at the Fermilab Tevatron. We observe 16 WZ candidates passing our event selection with an expected background of 2.7 +/- 0.4 events. A fit to the missing transverse energy distribution indicates an excess of events compared to the background expectation corresponding to a significance equivalent to six standard deviations. The measured cross section is sigma(ppbar -> WZ) = 5.0^{+1.8}_{-1.6} pb, consistent with the standard model expectation.Comment: 7 pages, 3 figures. Submitted to Phys. Rev. Let
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