3,061 research outputs found

    Achieving high coverage of larval-stage mosquito surveillance: challenges for a community-based mosquito control programme in urban Dar es Salaam, Tanzania

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    Background: Preventing malaria by controlling mosquitoes in their larval stages requires regular sensitive monitoring of vector populations and intervention coverage. The study assessed the effectiveness of operational, community-based larval habitat surveillance systems within the Urban Malaria Control Programme (UMCP) in urban Dar es Salaam, Tanzania. Methods: Cross-sectional surveys were carried out to assess the ability of community-owned resource persons (CORPs) to detect mosquito breeding sites and larvae in areas with and without larviciding. Potential environmental and programmatic determinants of habitat detection coverage and detection sensitivity of mosquito larvae were recorded during guided walks with 64 different CORPs to assess the accuracy of data each had collected the previous day. Results: CORPs reported the presence of 66.2% of all aquatic habitats (1,963/2,965), but only detected Anopheles larvae in 12.6% (29/230) of habitats that contained them. Detection sensitivity was particularly low for late-stage Anopheles (2.7%, 3/111), the most direct programmatic indicator of malaria vector productivity. Whether a CORP found a wet habitat or not was associated with his/her unfamiliarity with the area (Odds Ratio (OR) [95% confidence interval (CI)] = 0.16 [0.130, 0.203], P < 0.001), the habitat type (P < 0.001) or a fence around the compound (OR [95% CI] = 0.50 [0.386, 0.646], P < 0.001). The majority of mosquito larvae (Anophelines 57.8% (133/230) and Culicines 55.9% (461/825) were not reported because their habitats were not found. The only factor affecting detection of Anopheline larvae in habitats that were reported by CORPs was larviciding, which reduced sensitivity (OR [95% CI] = 0.37 [0.142, 0.965], P = 0.042). Conclusions: Accessibility of habitats in urban settings presents a major challenge because the majority of compounds are fenced for security reasons. Furthermore, CORPs under-reported larvae especially where larvicides were applied. This UMCP system for larval surveillance in cities must be urgently revised to improve access to enclosed compounds and the sensitivity with which habitats are searched for larvae

    DATASET2050 D3.2 - Future Passenger Demand Profile

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    The FlightPath 2050 goal of enabling 90 per cent of European passengers to complete their door-to-door journey within four hours is a very challenging task. A major objective of the DATASET2050 project is to deliver insight into both current and future processes relating to the European transport system in this context. The deliverable D3.2 "Future Passenger Demand Profile" focuses on the future demand side of European (air) transport. Namely, the first goal is to develop a range of passenger profiles for the year 2035 and to provide implications for passenger profiles for 2050. For this purpose, the development of passenger characteristics - including demographic, geographic, socio-economic and behavioural aspects as well as particular mobility patterns - is analysed using available European data and forecasts. Based on this analysis, on specific mobility behaviour of the different member states (EU28 and EFTA countries) as well as on a high-level-factor identification, six different passenger profiles for 2035 are developed. These six profiles differ by main travel purpose (private, business and leisure, which is the combination of business and leisure trips), predominant age group, income level (low, medium, high) and several other characteristics. Furthermore, a demand model is applied showing the high relevance of gross domestic product (GDP) and education for a steady growth of passenger traffic volume in the EU28 and EFTA countries until 2050. The outcomes of the current deliverable will be put in contrast with those coming from D4.2 (Future supply profile), enabling thus a comprehensive assessment on the European door-to-door mobility in the future. Specifically, the deliverable results will be used in D5.1 (Mobility assessment), D5.2 (Assessment execution) and D5.3 (Novel concept foundations for European mobility)

    Implementation of higher-order absorbing boundary conditions for the Einstein equations

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    We present an implementation of absorbing boundary conditions for the Einstein equations based on the recent work of Buchman and Sarbach. In this paper, we assume that spacetime may be linearized about Minkowski space close to the outer boundary, which is taken to be a coordinate sphere. We reformulate the boundary conditions as conditions on the gauge-invariant Regge-Wheeler-Zerilli scalars. Higher-order radial derivatives are eliminated by rewriting the boundary conditions as a system of ODEs for a set of auxiliary variables intrinsic to the boundary. From these we construct boundary data for a set of well-posed constraint-preserving boundary conditions for the Einstein equations in a first-order generalized harmonic formulation. This construction has direct applications to outer boundary conditions in simulations of isolated systems (e.g., binary black holes) as well as to the problem of Cauchy-perturbative matching. As a test problem for our numerical implementation, we consider linearized multipolar gravitational waves in TT gauge, with angular momentum numbers l=2 (Teukolsky waves), 3 and 4. We demonstrate that the perfectly absorbing boundary condition B_L of order L=l yields no spurious reflections to linear order in perturbation theory. This is in contrast to the lower-order absorbing boundary conditions B_L with L<l, which include the widely used freezing-Psi_0 boundary condition that imposes the vanishing of the Newman-Penrose scalar Psi_0.Comment: 25 pages, 9 figures. Minor clarifications. Final version to appear in Class. Quantum Grav

    The enigma of GCIRS 3 - Constraining the properties of the mid-infrared reference star of the central parsec of the Milky Way with optical long baseline interferometry

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    GCIRS3 is the most prominent MIR source in the central pc of the Galaxy. NIR spectroscopy failed to solve the enigma of its nature. The properties of extreme individual objects of the central stellar cluster contribute to our knowledge of star and dust formation close to a supermassive black hole. We initiated an interferometric experiment to understand IRS3 and investigate its properties as spectroscopic and interferometric reference star at 10um. VISIR imaging separates a compact source from diffuse, surrounding emission. The VLTI/MIDI instrument was used to measure visibilities at 10mas resolution of that compact 10um source, still unresolved by a single VLT. Photometry data were added to enable simple SED- and full radiative transfer-models of the data. The luminosity and size estimates show that IRS3 is probably a cool carbon star enshrouded by a complex dust distribution. Dust temperatures were derived. The coinciding interpretation of multiple datasets confirm dust emission at several spatial scales. The IF data resolve the innermost area of dust formation. Despite observed deep silicate absorption towards IRS3 we favor a carbon rich chemistry of the circumstellar dust shell. The silicate absorption most probably takes place in the outer diffuse dust, which is mostly ignored by MIDI measurements. This indicates physically and chemically distinct conditions of the local dust, changing with the distance to IRS3. We have demonstrated that optical long baseline interferometry at infrared wavelengths is an indispensable tool to investigate sources at the Galactic Center. Our findings suggest further studies of the composition of interstellar dust and the shape of the 10um silicate feature at this outstanding region.Comment: accepted by A&A, now in press; 19 pages, 22 figures, 5 table

    DATASET2050 D5.2 - Assessment execution

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    Over recent years there has been an increasing effort to enhance European door-to-door mobility. Several initiatives have focused on improving the seamlessness, effectiveness and predictability of the European transport system through improving the related systems, technologies, concepts or processes. In an effort to establish a concrete methodology for assessing the system's current performance, this document describes a data-driven model centred on the current and future performance of European mobility. Included in this study, but not restricted to, is data and insight related to the Flightpath 2050 goal that states "90% of travellers within Europe [will be] able to complete their journey, door-to-door within four hours" where this journey includes at least one leg by air. In this report, the current door-to-door times and prices are quantified, dis-aggregated by passenger profile, door-to-door phase (door-kerb-gate-gate-kerb-door) and airport considered. In addition, major bottlenecks are identified that are hindering the 4-hour goal

    Dual Microsporidial Infection Due to Vittaforma corneae and Encephalitozoon hellem in a Patient with AIDS

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    A 46-year-old human immunodeficiency virus-infected Swiss citizen living in Tanzania presented with respiratory, abdominal, and urogenital complaints. Microsporidial spores were isolated from urine and a sinunasal aspirate and were propagated in MRC-5 cell cultures. Western blot analysis and riboprinting identified the sinunasal isolate as Encephalitozoon hellem. Electron microscopic investigation of the urine isolate revealed spores with diplokaryotic nuclei and five to six isofilar coils of the polar tube and sporonts with two or three diplokarya. All stages were enveloped by two membranes, corresponding to a cisterna of host endoplasmic reticulum studded with ribosomes. These characteristics have been described for the genus Vittaforma. Western blot analysis of this isolate revealed a banding pattern identical to that of the Vittaforma corneae reference isolate. Part of the small subunit rRNA gene was amplified, sequenced (239 base pairs), and found to be identical to that of V. corneae. This is the second isolation of V. corneae and the first description of urinary tract infection due to V. corneae in a patient with AID

    NACO/SAM observations of sources at the Galactic Center

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    Sparse aperture masking (SAM) interferometry combined with Adaptive Optics (AO) is a technique that is uniquely suited to investigate structures near the diffraction limit of large telescopes. The strengths of the technique are a robust calibration of the Point Spread Function (PSF) while maintaining a relatively high dynamic range. We used SAM+AO observations to investigate the circumstellar environment of several bright sources with infrared excess in the central parsec of the Galaxy. For our observations, unstable atmospheric conditions as well as significant residuals after the background subtraction presented serious problems for the standard approach of calibrating SAM data via interspersed observations of reference stars. We circumvented these difficulties by constructing a synthesized calibrator directly from sources within the field-of-view. When observing crowded fields, this novel method can boost the efficiency of SAM observations because it renders interspersed calibrator observations unnecessary. Here, we presented the first NaCo/SAM images reconstructed using this method.Comment: 8 pages, 10 figures, proceedings of the conference "Astrophysics at High Angular Resolution" (AHAR-2011

    Quantum ergodicity for graphs related to interval maps

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    We prove quantum ergodicity for a family of graphs that are obtained from ergodic one-dimensional maps of an interval using a procedure introduced by Pakonski et al (J. Phys. A, v. 34, 9303-9317 (2001)). As observables we take the L^2 functions on the interval. The proof is based on the periodic orbit expansion of a majorant of the quantum variance. Specifically, given a one-dimensional, Lebesgue-measure-preserving map of an interval, we consider an increasingly refined sequence of partitions of the interval. To this sequence we associate a sequence of graphs, whose directed edges correspond to elements of the partitions and on which the classical dynamics approximates the Perron-Frobenius operator corresponding to the map. We show that, except possibly for subsequences of density 0, the eigenstates of the quantum graphs equidistribute in the limit of large graphs. For a smaller class of observables we also show that the Egorov property, a correspondence between classical and quantum evolution in the semiclassical limit, holds for the quantum graphs in question.Comment: 20 pages, 1 figur
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