756 research outputs found

    Application of advanced technologies to small, short-haul transport aircraft (STAT)

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    The benefits of selected advanced technologies for 19 and 30 passenger, short-haul aircraft were identified. Advanced technologies were investigated in four areas: aerodynamics, propulsion, structures, and ride quality. Configuration sensitivity studies were conducted to show design tradeoffs associated with passenger capacity, cabin comfort level, and design field length

    Corporate Governance, Opaque Bank Activities, and Risk/Return Efficiency: Pre- and Post-Crisis Evidence from Turkey

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    Does better corporate governance unambiguously improve the risk/return efficiency of banks? Or does either a re-orientation of banks' revenue mix towards more opaque products, an economic downturn, or tighter supervision create off-setting or reinforcing effects? The authors relate bank efficiency to shortfalls from a stochastic risk/return frontier. They analyze how internal governance mechanisms (CEO duality, board experience, political connections, and education profile) and external governance mechanisms (discipline exerted by shareholders, depositors, or skilled employees) determine efficiency in a sample of Turkish banks. The 2000 financial crisis was a wakeup call for bank efficiency and corporate governance. As a result, better corporate governance mechanisms have been able to improve risk/return efficiency when the economic, regulatory, and supervisory environments are more stable and bank products are more complex.corporate governance;bank risk;noninterest income;crisis;frontier

    Surveillance and Outbreak Response Management System (SORMAS) to support the control of the Ebola virus disease outbreak in West Africa

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    In the context of controlling the current outbreak of Ebola virus disease (EVD), the World Health Organization claimed that ‘critical determinant of epidemic size appears to be the speed of implementation of rigorous control measures’, i.e. immediate follow-up of contact persons during 21 days after exposure, isolation and treatment of cases, decontamination, and safe burials. We developed the Surveillance and Outbreak Response Management System (SORMAS) to improve efficiency and timeliness of these measures. We used the Design Thinking methodology to systematically analyse experiences from field workers and the Ebola Emergency Operations Centre (EOC) after successful control of the EVD outbreak in Nigeria. We developed a process model with seven personas representing the procedures of EVD outbreak control. The SORMAS system architecture combines latest In-Memory Database (IMDB) technology via SAP HANA (in-memory, relational database management system), enabling interactive data analyses, and established SAP cloud tools, such as SAP Afaria (a mobile device management software). The user interface consists of specific front-ends for smartphones and tablet devices, which are independent from physical configurations. SORMAS allows real-time, bidirectional information exchange between field workers and the EOC, ensures supervision of contact follow-up, automated status reports, and GPS tracking. SORMAS may become a platform for outbreak management and improved routine surveillance of any infectious disease. Furthermore, the SORMAS process model may serve as framework for EVD outbreak modelling

    User evaluation indicates high quality of the Surveillance Outbreak Response Management and Analysis System (SORMAS) after field deployment in Nigeria in 2015 and 2018

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    During the West African Ebola virus disease outbreak in 2014-15, health agencies had severe challenges with case notification and contact tracing. To overcome these, we developed the Surveillance, Outbreak Response Management and Analysis System (SORMAS). The objective of this study was to measure perceived quality of SORMAS and its change over time. We ran a 4-week-pilot and 8-week-implementation of SORMAS among hospital informants in Kano state, Nigeria in 2015 and 2018 respectively. We carried out surveys after the pilot and implementation asking about usefulness and acceptability. We calculated the proportions of users per answer together with their 95% confidence intervals (CI) and compared whether the 2015 response distributions differed from those from 2018. Total of 31 and 74 hospital informants participated in the survey in 2015 and 2018, respectively. In 2018, 94% (CI: 89-100%) of users indicated that the tool was useful, 92% (CI: 86-98%) would recommend SORMAS to colleagues and 18% (CI: 10-28%) had login difficulties. In 2015, the proportions were 74% (CI: 59-90%), 90% (CI: 80-100%), and 87% (CI: 75-99%) respectively. Results indicate high usefulness and acceptability of SORMAS. We recommend mHealth tools to be evaluated to allow repeated measurements and comparisons between different versions and users

    Development of chronic bronchitis and emphysema in β-epithelial Na+ channel-overexpressing mice

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    Rationale: Chronic obstructive pulmonary disease is a leading cause of death worldwide, but its pathogenesis is not well understood. Previous studies have shown that airway surface dehydration in β-epithelial Na+ channel (βENaC)-overexpressing mice caused a chronic lung disease with high neonatal pulmonary mortality and chronic bronchitis in adult survivors. Objectives: The aim of this study was to identify the initiating lesions and investigate the natural progression of lung disease caused by airway surface dehydration. Methods: Lung morphology, gene expression, bronchoalveolar lavage, and lung mechanics were studied at different ages in βENaC-overexpressing mice. Measurements and Main Results: Mucus obstruction in βENaC- overexpressing mice originated in the trachea in the first days of life and was associated with hypoxia, airway epithelial necrosis, and death. In surviving βENaC-overexpressing mice, mucus obstruction extended into the lungs and was accompanied by goblet cell metaplasia, increased mucin expression, and airway inflammation with transient perinatal increases in tumor necrosis factor-α and macrophages, IL-13 and eosinophils, and persistent increases inkeratinocyte-derived cytokine (KC), neutrophils, and chitinases in the lung. βENaC-overexpressing mice also developed emphysema with increased lung volumes, distal airspace enlargement, and increased lung compliance. Conclusions: Our studies demonstrate that airway surface dehydration is sufficient toinitiatepersistentneutrophilic airway inflammation with chronic airways mucus obstruction and to cause transient eosinophilic airway inflammation and emphysema. These results suggest that deficient airway surface hydration may play a critical role in the pathogenesis of chronic obstructive pulmonary diseases of different etiologies and serve as a target for novel therapies

    Measurements of D0D^{0} and DD^{*} Production in pp + pp Collisions at s\sqrt{s} = 200 GeV

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    We report measurements of charmed-hadron (D0D^{0}, DD^{*}) production cross sections at mid-rapidity in pp + pp collisions at a center-of-mass energy of 200 GeV by the STAR experiment. Charmed hadrons were reconstructed via the hadronic decays D0Kπ+D^{0}\rightarrow K^{-}\pi^{+}, D+D0π+Kπ+π+D^{*+}\rightarrow D^{0}\pi^{+}\rightarrow K^{-}\pi^{+}\pi^{+} and their charge conjugates, covering the pTp_T range of 0.6-2.0 GeV/cc and 2.0-6.0 GeV/cc for D0D^{0} and D+D^{*+}, respectively. From this analysis, the charm-pair production cross section at mid-rapidity is dσ/dyy=0ccˉd\sigma/dy|_{y=0}^{c\bar{c}} = 170 ±\pm 45 (stat.) 59+38^{+38}_{-59} (sys.) μ\mub. The extracted charm-pair cross section is compared to perturbative QCD calculations. The transverse momentum differential cross section is found to be consistent with the upper bound of a Fixed-Order Next-to-Leading Logarithm calculation.Comment: 15 pages, 16 figures. Revised version submitted to Phys. Rev.

    Measurements of Dihadron Correlations Relative to the Event Plane in Au+Au Collisions at sNN=200\sqrt{s_{NN}}=200 GeV

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    Dihadron azimuthal correlations containing a high transverse momentum (\pt) trigger particle are sensitive to the properties of the nuclear medium created at RHIC through the strong interactions occurring between the traversing parton and the medium, i.e. jet-quenching. Previous measurements revealed a strong modification to dihadron azimuthal correlations in Au+Au collisions with respect to \pp\ and \dAu\ collisions. The modification increases with the collision centrality, suggesting a path-length dependence to the jet-quenching effect. This paper reports STAR measurements of dihadron azimuthal correlations in mid-central (20-60\%) Au+Au collisions at \snn=200~GeV as a function of the trigger particle's azimuthal angle relative to the event plane, \phis=|\phit-\psiEP|. The azimuthal correlation is studied as a function of both the trigger and associated particle \pt. The subtractions of the combinatorial background and anisotropic flow, assuming Zero Yield At Minimum (\zyam), are described. The away-side correlation is strongly modified, and the modification varies with \phis, which is expected to be related to the path-length that the away-side parton traverses. The pseudo-rapidity (\deta) dependence of the near-side correlation, sensitive to long range \deta correlations (the ridge), is also investigated. The ridge and jet-like components of the near-side correlation are studied as a function of \phis. The ridge appears to drop with increasing \phis while the jet-like component remains approximately constant. ...Comment: 50 pages, 39 figures, 6 table

    System size and energy dependence of near-side di-hadron correlations

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    Two-particle azimuthal (Δϕ\Delta\phi) and pseudorapidity (Δη\Delta\eta) correlations using a trigger particle with large transverse momentum (pTp_T) in dd+Au, Cu+Cu and Au+Au collisions at sNN\sqrt{s_{{NN}}} =\xspace 62.4 GeV and 200~GeV from the STAR experiment at RHIC are presented. The \ns correlation is separated into a jet-like component, narrow in both Δϕ\Delta\phi and Δη\Delta\eta, and the ridge, narrow in Δϕ\Delta\phi but broad in Δη\Delta\eta. Both components are studied as a function of collision centrality, and the jet-like correlation is studied as a function of the trigger and associated pTp_T. The behavior of the jet-like component is remarkably consistent for different collision systems, suggesting it is produced by fragmentation. The width of the jet-like correlation is found to increase with the system size. The ridge, previously observed in Au+Au collisions at sNN\sqrt{s_{{NN}}} = 200 GeV, is also found in Cu+Cu collisions and in collisions at sNN\sqrt{s_{{NN}}} =\xspace 62.4 GeV, but is found to be substantially smaller at sNN\sqrt{s_{{NN}}} =\xspace 62.4 GeV than at sNN\sqrt{s_{{NN}}} = 200 GeV for the same average number of participants (Npart \langle N_{\mathrm{part}}\rangle). Measurements of the ridge are compared to models.Comment: 17 pages, 14 figures, submitted to Phys. Rev.
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