7,261 research outputs found

    Review of geographical stocks of tropical dolphins (Stenella spp. and Delphinus delphis) in the eastern Pacific

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    Information on geographical variation is reviewed for Stenella attenuata, S. longirostris, S. coeruleoalba, and Delphinus delphis in the eastern tropical Pacific, and boundaries for potential management units are proposed. National Marine Fisheries Service and Inter-American Tropical Tuna Commission sighting records made from 1979 to 1983 which were outside boundaries used in a 1979 assessment were examined for validity. Tagging returns and morphological data were also analyzed. Several stock ranges are expanded or combined. Three management units are proposed for S. attenuata: the coastal, northern offshore, and southern offshore spoiled dolphins. Four management units are proposed for S. longirostris: the Costa Rican, eastern, northern whitebelly, and southern whitebelly spinner dolphins. Two provisional management units are proposed for S. coeruleoalba: the northern and southern striped dolphins. Five management units (two of which are provisional) are proposed for D. delphis: the Baja neritic, northern, central, southern, and Guerrero common dolphins. Division into management units was based on morphological stock differences and distributional breaks. (PDF file contains 34 pages.

    Selected 2017 Highlights in Congenital Cardiac Anesthesia

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    This article is a review of the highlights of pertinent literature published during the 12 months of 2017, which is of interest to the congenital cardiac anesthesiologist. Following a search of the US National Library of Medicine PubMed database, several topics emerged where significant contributions were made in 2017, and that the authors of this manuscript felt were noteworthy to be summarized in this review: Training in pediatric cardiac anesthesia, the costs of congenital heart disease (CHD), catheter versus surgical intervention for CHD, cerebral oxygen saturation in CHD, and mechanical circulatory support in children

    Health and economic benefits of achieving hepatitis C virus elimination in Pakistan: A modelling study and economic analysis

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    Background: Modelling suggests that achieving the WHO incidence target for hepatitis C virus (HCV) elimination in Pakistan could cost US3.87billionover2018to2030.However,theeconomicbenefitsfromintegratingservicesorimprovingproductivitywerenotincluded.Methodsandfindings:WeadaptaHCVtransmissionmodelforPakistantoestimatetheimpact,costs,andcost−effectivenessofachievingHCVelimination(reducingannualHCVincidenceby803.87 billion over 2018 to 2030. However, the economic benefits from integrating services or improving productivity were not included.Methods and findings: We adapt a HCV transmission model for Pakistan to estimate the impact, costs, and cost-effectiveness of achieving HCV elimination (reducing annual HCV incidence by 80% by 2030) with stand-alone service delivery, or partially integrating one-third of initial HCV testing into existing healthcare services. We estimate the net economic benefits by comparing the required investment in screening, treatment, and healthcare management to the economic productivity gains from reduced HCV-attributable absenteeism, presenteeism, and premature deaths. We also calculate the incremental cost-effectiveness ratio (ICER) per disability-adjusted life year (DALY) averted for HCV elimination versus maintaining current levels of HCV treatment. This is compared to an opportunity cost-based willingness-to-pay threshold for Pakistan (US148 to US198/DALY).Comparedtoexistinglevelsoftreatment,scalingupscreeningandtreatmenttoachieveHCVeliminationinPakistanaverts5.57(95198/DALY). Compared to existing levels of treatment, scaling up screening and treatment to achieve HCV elimination in Pakistan averts 5.57 (95% uncertainty interval (UI) 3.80 to 8.22) million DALYs and 333,000 (219,000 to 509,000) HCV-related deaths over 2018 to 2030. If HCV testing is partially integrated, this scale-up requires an investment of US1.45 (1.32 to 1.60) billion but will result in US1.30(0.94to1.72)billioninimprovedeconomicproductivityover2018to2030.Thiseliminationstrategyishighlycost−effective(ICER=US1.30 (0.94 to 1.72) billion in improved economic productivity over 2018 to 2030. This elimination strategy is highly cost-effective (ICER = US29 per DALY averted) by 2030, with it becoming cost-saving by 2031 and having a net economic benefit of US$9.10 (95% UI 6.54 to 11.99) billion by 2050. Limitations include uncertainty around what level of integration is possible within existing primary healthcare services as well as a lack of Pakistan-specific data on disease-related healthcare management costs or productivity losses due to HCV.Conclusions: Investment in HCV elimination can bring about substantial societal health and economic benefits for Pakistan

    Transport Properties of Highly Aligned Polymer Light-Emitting-Diodes

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    We investigate hole transport in polymer light-emitting-diodes in which the emissive layer is made of liquid-crystalline polymer chains aligned perpendicular to the direction of transport. Calculations of the current as a function of time via a random-walk model show excellent qualitative agreement with experiments conducted on electroluminescent polyfluorene demonstrating non-dispersive hole transport. The current exhibits a constant plateau as the charge carriers move with a time-independent drift velocity, followed by a long tail when they reach the collecting electrode. Variation of the parameters within the model allows the investigation of the transition from non-dispersive to dispersive transport in highly aligned polymers. It turns out that large inter-chain hopping is required for non-dispersive hole transport and that structural disorder obstructs the propagation of holes through the polymer film.Comment: 4 pages, 5 figure

    Pharmacokinetics of Cefuroxime are not Significantly Altered by Cardiopulmonary Bypass in Children

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    Poster presented at: SPA/AAP PEDIATRIC ANESTHESIOLOGY 2010 - Winter Meeting; April 2010; San Antonio, TX

    A Randomized, Controlled Trial of Catheter-Related Infectious Event Rates Using Antibiotic-Impregnated Catheters Versus Conventional Catheters in Pediatric Cardiovascular Surgery Patients

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    We conducted a randomized, controlled clinical trial to determine whether a difference in catheter-associated blood stream infection (CABSI) incidence existed between children who underwent cardiac surgery and had a central venous catheter impregnated with minocycline and rifampin versus those who had a conventional, nonimpregnated catheter after cardiac surgery. Due to a lower number of infections than expected, the study was terminated early. Among 288 evaluable patients, the rates of CABSI and line-related complications were similar between the 2 groups

    Temperature and Field Dependence of the Mobility in Liquid-Crystalline Conjugated Polymer Films

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    The transport properties of organic light-emitting diodes in which the emissive layer is composed of conjugated polymers in the liquid-crystalline phase have been investigated. We have performed simulations of the current transient response to an illumination pulse via the Monte Carlo approach, and from the transit times we have extracted the mobility of the charge carriers as a function of both the electric field and the temperature. The transport properties of such films are different from their disordered counterparts, with charge carrier mobilities exhibiting only a weak dependence on both the electric field and temperature. We show that for spatially ordered polymer films, this weak dependence arises for thermal energy being comparable to the energetic disorder, due to the combined effect of the electrostatic and thermal energies. The inclusion of spatial disorder, on the other hand, does not alter the qualitative behaviour of the mobility, but results in decreasing its absolute value.Comment: 9 pages, 8 figures, submitted to Phys. Rev.

    Brush Seals for Cryogenic Applications: Performance, Stage Effects, and Preliminary Wear Results in LN2 and LH2

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    Brush seals are compliant contacting seals and have significantly lower leakage than labyrinth seals in gas turbine applications. Their long life and low leakage make them candidates for use in rocket engine turbopumps. Brush seals, 50.8 mm (2 in.) in diameter with a nominal 127-micron (0.005-in.) radial interference, were tested in liquid nitrogen (LN2) and liquid hydrogen (LH2) at shaft speeds up to 35,000 and 65,000 rpm, respectively, and at pressure drops up to 1.21 MPa (175 psid) per brush. A labyrinth seal was also tested in liquid nitrogen to provide a baseline. The LN2 leakage rate of a single brush seal with an initial radial shaft interference of 127 micron (0.005 in.) measured one-half to one-third the leakage rate of a 12-tooth labyrinth seal with a radial clearance of 127 micron (0.005 in.). Two brushes spaced 7.21 micron (0.248 in.) apart leaked about one-half as much as a single brush, and two brushes tightly packed together leaked about three-fourths as much as a single brush. The maximum measured groove depth on the Inconel 718 rotor with a surface finish of 0.81 micron (32 microinch) was 25 micron (0.0010 in.) after 4.3 hr of shaft rotation in liquid nitrogen. The Haynes-25 bristles wore approximately 25 to 76 micron (0.001 to 0.003 in.) under the same conditions. Wear results in liquid hydrogen were significantly different. In liquid hydrogen the rotor did not wear, but the bristle material transferred onto the rotor and the initial 127 micron (0.005 in.) radial interference was consumed. Relatively high leakage rates were measured in liquid hydrogen. More testing is required to verify the leakage performance, to validate and calibrate analysis techniques, and to determine the wear mechanisms. Performance, staging effects, and preliminary wear results are presented
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