3,473 research outputs found

    Development of a Graphical User Interface for In-Core Fuel Management Using MCODE

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    In the present work, a graphical user interface is developed to automate in-core fuel management using MCODE, an MCNP-ORIGEN linkage code. Data abstraction is achieved by means of five object classes that define the run, fuel assembly locations, fuel assemblies, fuel paths, and materials. The GUI and an associated fuel management wrapper were developed in Python, with the PyQt extension being used for GUI-specific features. To validate the fuel management wrapper, a model of the MIT Reactor core was used to run an equilibrium core. The results show that the wrapper performs reliably. Together, these tools will help the staff at the MITR perform in-core fuel management calculations quickly and with a higher level of detail than that previously possible

    Encapsulation of pentacene/C₆₀ organic solar cells with Al₂O₃ deposited by atomic layer deposition

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    © 2007 American Institute of Physics. The electronic version of this article is the complete one and can be found at: http://dx.doi.org/10.1063/1.2751108DOI: 10.1063/1.2751108Organic solar cells based on pentacene/C₆₀ heterojunctions were encapsulated using a 200-nm-thick film of Al₂O₃ deposited by atomic layer deposition (ALD). Encapsulated devices maintained power conversion efficiency after exposure to ambient atmosphere for over 6000 h, while devices with no encapsulation degraded rapidly after only 10 h of air exposure. In addition, thermal annealing associated with the ALD deposition is shown to improve the open-circuit voltage and power conversion efficiency of the solar cells

    Understanding the Impact of Childhood Sexual Abuse on Men’s Risk Behavior: Protocol for a Mixed-Methods Study

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    Background: Childhood sexual abuse (CSA) remains a critical public health issue among black and Latino men who have sex with men (MSM), as it is associated with multiple negative outcomes including substance misuse, poor mental health, revictimization, and high-risk sexual behavior. Most CSA research with MSM relies on quantitative assessment that often precludes consideration of cultural variations in how formative sexual experiences are understood and is based on inconsistent or overly restrictive definitions of abuse, and therefore may fail to detect certain abusive experiences (eg, those involving female perpetrators), which can have harmful health consequences if they remain unrecognized. Objective: The objective of this study is to overcome existing limitations in the literature by drawing on perspectives of black and Latino MSM and men who have sex with men and women (MSMW), as well as relevant service providers to better understand the role of, and the need to include, sexual abuse histories (eg, CSA) in treatment and counseling settings, with the long-term goal of improving assessment and health outcomes. Methods: We will conduct mixed-methods interviews, framed by an intersectionality approach, with 80 black and Latino men (40 MSM and 40 MSMW) in New York City (NYC), exploring appraisals of their formative sexual experiences, including those described as consensual but meeting criteria for CSA. We will also interview 30 local service providers representing substance abuse treatment, mental health care, and HIV prevention and outreach. Results: The study was launched in May 2017. Conclusions: This formative research will inform testable approaches to assessing and incorporating sexual abuse history into substance abuse treatment and other health and mental health services used by men with such histories

    Validation of a new automatic smoking machine to study the effects of cigarette smoke in newborn lambs

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    The aim of this study was to describe the characteristics and validate the use of a new, custom-built automatic smoking machine (ASM), primarily designed to study the effects of an environmental tobacco smoke surrogate (ETS surrogate) exposure in animals of various sizes, including large animals. The equipment includes a programmable ASM coupled to a vented whole body chamber, where animals can be exposed to both mainstream and sidestream smoke. The user-friendly interface allows for full programming of puff volume (1-60 mL), time interval between two puffs (1-60 s) and between two cigarettes (1-60 min). Eight newborn lambs were exposed to either 10 (4 lambs, C10 group) or 20 (4 lambs, C20 group) cigarettes, 8 h per day for 15 days. Four additional control, lambs were exposed to air (C0 group). Weight gain was identical in all three groups of lambs. Urinary cotinine/creatinine ratio increased with the number of cigarettes smoked (C0: 11 ± 7 ng/mg; C10: 961 ± 539 ng/mg; C20: 1821 ± 312 ng/mg), with levels in the C10 and C20 groups in keeping with values published in infants exposed to ETS. Overall, results show that our new ASM is especially well suited for ETS surrogate exposure in non-restrained, non-anaesthetized large animals such as sheep

    Party control, party competition and public service performance

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    publication-status: Acceptedtypes: ArticleThis article assesses party effects on the performance of public services. A policy-seeking model, hypothesizing that left and right party control affects performance, and an instrumental model, where all parties strive to raise performance, are presented. The framework also suggests a mixed model in which party effects are contingent on party competition, with parties raising performance as increasing party competition places their control of government at increasing risk. These models are tested against panel data on English local governments’ party control and public service performance. The results question the traditional account of left and right parties, showing a positive relationship between rightwing party control and performance that is contingent on a sufficiently high level of party competition. The findings suggest left–right models should be reframed for the contemporary context

    Preliminary Design of the SAFE Platform

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    Safe is a clean-slate design for a secure host architecture. It integrates advances in programming languages, operating systems, and hardware and incorporates formal methods at every step. Though the project is still at an early stage, we have assembled a set of basic architectural choices that we believe will yield a high-assurance system. We sketch the current state of the design and discuss several of these choices

    Synergies for Improving Oil Palm Production and Forest Conservation in Floodplain Landscapes

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    Lowland tropical forests are increasingly threatened with conversion to oil palm as global demand and high profit drives crop expansion throughout the world’s tropical regions. Yet, landscapes are not homogeneous and regional constraints dictate land suitability for this crop. We conducted a regional study to investigate spatial and economic components of forest conversion to oil palm within a tropical floodplain in the Lower Kinabatangan, Sabah, Malaysian Borneo. The Kinabatangan ecosystem harbours significant biodiversity with globally threatened species but has suffered forest loss and fragmentation. We mapped the oil palm and forested landscapes (using object-based-image analysis, classification and regression tree analysis and on-screen digitising of high-resolution imagery) and undertook economic modelling. Within the study region (520,269 ha), 250,617 ha is cultivated with oil palm with 77% having high Net-Present-Value (NPV) estimates (413/ha?yr–413/ha?yr–637/ha?yr); but 20.5% is under-producing. In fact 6.3% (15,810 ha) of oil palm is commercially redundant (with negative NPV of −299/ha?yr−-299/ha?yr--65/ha?yr) due to palm mortality from flood inundation. These areas would have been important riparian or flooded forest types. Moreover, 30,173 ha of unprotected forest remain and despite its value for connectivity and biodiversity 64% is allocated for future oil palm. However, we estimate that at minimum 54% of these forests are unsuitable for this crop due to inundation events. If conversion to oil palm occurs, we predict a further 16,207 ha will become commercially redundant. This means that over 32,000 ha of forest within the floodplain would have been converted for little or no financial gain yet with significant cost to the ecosystem. Our findings have globally relevant implications for similar floodplain landscapes undergoing forest transformation to agriculture such as oil palm. Understanding landscape level constraints to this crop, and transferring these into policy and practice, may provide conservation and economic opportunities within these seemingly high opportunity cost landscapes

    The interplay between double exchange, super-exchange, and Lifshitz localization in doped manganites

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    Considering the disorder caused in manganites by the substitution of Mn by Fe or Ga, we accomplish a systematic study of doped manganites begun in previous papers. To this end, a disordered model is formulated and solved using the Variational Mean Field technique. The subtle interplay between double exchange, super-exchange, and disorder causes similar effects on the dependence of T_C on the percentage of Mn substitution in the cases considered. Yet, in La2/3_{2/3}Ca1/3_{1/3}Mn1−y_{1-y}Gay_yO3_3 our results suggest a quantum critical point (QCP) for y≈0.1−0.2y\approx 0.1-0.2, associated to the localization of the electronic states of the conduction band. In the case of Lax_xCax_xMn1−y_{1-y}Fey_yO3_3 (with x=1/3,3/8x=1/3,3/8) no such QCP is expected.Comment: 6 pages + 3 postscript figures. Largely extended discussio
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