1,712 research outputs found

    The pro-poorness, growth and inequality nexus: Some findings from a simulation study

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    A widely accepted criterion for pro-poorness of an income growth pattern is that it should reduce a (chosen) measure of poverty by more than if all incomes were growing equiproportionately. Inequality reduction is not generally seen as either necessary or sufficient for pro-poorness. As shown in Lambert (2010), in order to conduct nuanced investigation of the pro-poorness, growth and inequality nexus, one needs at least a 3-parameter model of the income distribution. In this paper, we explore in detail the properties of inequality reduction and pro-poorness, using the Watts poverty index and Gini inequality index, when income growth takes place within each of the following models: the displaced lognormal, Singh-Maddala and Dagum distributions. We show by simulation, using empirically relevant parameter estimates, that distributional change preserving the form of each of these income distributions is, in the main, either pro-poor and inequality reducing, or pro-rich and inequality exacerbating. Instances of pro-rich and inequality reducing change do occur, but we find no evidence that distributional change could be both pro-poor and inequality exacerbating.poverty, growth, pro-poorness, income distribution.

    Heat pipes for spacecraft temperature control: An assessment of the state-of-the-art

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    Various heat pipe temperature control techniques are critically evaluated using characteristic features and properties, including heat transport capability, volume and mass requirements, complexity and ease of fabrication, reliability, and control characteristics. Advantages and disadvantages of specific approaches are derived and discussed. Using four development levels, the state of-the-art of the various heat pipe temperature control techniques is assessed. The need for further research and development is discussed and suggested future efforts are projected

    Measuring Concentration in Data with an Exogenous Order

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    Concentration measures order the statistical units under observation according to their market share. However, there are situations where an order according to an exogenous variable is more appropriate or even required. The present article introduces a generalized definition of market concentration and defines a corresponding concentration measure. It is shown that this generalized concept of market concentration satisfies the common axioms of (classical) concentration measures. In an application example, the proposed approach is compared with classical concentration measures; the data are transfer spendings of German Bundesliga soccer teams, the ``obvious'' exogenous order of the teams is the league ranking

    Parametric performance of circumferentially grooved heat pipes with homogeneous and graded-porosity slab wicks at cryogenic temperatures

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    A recently developed, potentially high-performance nonarterial wick has been extensively tested. This slab wick has an axially varying porosity which can be tailored to match the local stress imposed on the wick. The purpose of the tests was to establish the usefulness of the graded-porosity slab wick at cryogenic temperatures between 110 K and 260 K, with methane and ethane as working fluids. For comparison, a homogeneous (i.e., uniform porosity) slab wick was also tested. The tests included: (1) maximum heat pipe performance as a function of fluid inventory, (2) maximum performance as a function of operating temperature, (3) maximum performance as a function of evaporator elevation, and (4) influence of slab wick orientation on performance. The experimental data was compared with theoretical predictions obtained with the computer program GRADE

    Repeated Lobbying by Commercial Lobbyists and Special Interests

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    Using a model of repeated agency, we explain previously unexplained features of the real-world lobbying industry. Lobbying is divided between direct representation by special interests to policymakers, and indirect representation where special interests employ professional intermediaries called commercial lobbyists to lobby policymakers on their behalf. Our analytical structure allows us to explain several trends in lobbying. For example, using the observation that in the U.S. over the last 20 years policymakers have spent an increasing amount of their time fundraising as opposed to legislating, we are able to explain why the share of commercial lobbyist activity in total lobbying has risen dramatically and now constitutes over 60% of the total. The key scarce resource in our analysis is policymakers’ time. They allocate this resource via implicit repeated agency contracts which are used to incent special interests and commercial lobbyists to provide a mix of financial contributions and information on policy proposals. These implicit agency contracts solve both an information problem in the presence of unverifiable policy information and a contracting problem in the absence of legal enforcement. These repeated relationship, that are often described using the pejorative term cronyism in the popular press, may in certain circumstances be welfare improving

    Thin-layer agar for detection of resistance to rifampicin, ofloxacin and kanamycin in Mycobacterium tuberculosis isolates

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    BACKGROUND: In low-income countries there is a great need for economical methods for testing the susceptibility of Mycobacterium tuberculosis to antibiotics. OBJECTIVE: To evaluate the thin-layer agar (TLA) for rapid detection of resistance to rifampicin (RMP), ofloxacin (OFX) and kanamycin (KM) in M. tuberculosis clinical isolates and to determine the sensitivity, specificity and time to positivity compared to the gold standard method. METHODS: One hundred and forty-seven clinical isolates of M. tuberculosis were studied. For the TLA method, a quadrant Petri plate containing 7H11 agar with RMP, OFX and KM was used. Results were compared to the Bactec MGIT960 for RMP and the proportion method for OFX and KM. RESULTS: The sensitivity and specificity for RMP and OFX were 100% and for KM they were 100% and 98.7%, respectively. The use of a TLA quadrant plate enables the rapid detection of resistance to the three anti-tuberculosis drugs RMP, OFX and KM in a median of 10 days. CONCLUSION: TLA was an accurate method for the detection of resistance in the three drugs studied. This faster method is simple to perform, providing an alternative method when more sophisticated techniques are not available in low-resource settings

    Modeling of S-RAM Energy Recover Compressor Integration in a Transcritical Carbon Dioxide Cycle for Application in Electronics Cooling in Varying Gravity

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    As electronics in military aircraft become increasingly complicated, additional cooling is necessary to enable efficient and high computing performance. Additionally, the varying forces that a military aircraft endure during maneuvering and inverted flight introduce unique design constraints to the electronics cooling systems. Because this cooling system will be in an aircraft, the capacity and unique design constraints must all be met with a design that is as lightweight as possible. This paper presents a study comparing the coefficient of performance (COP) of several cycle architectures with both R134a and carbon dioxide ( ). Cycles with single-stage and two-stage compression with intercooling are compared, and both are modeled with suction-to-liquid line heat exchangers. The cycles utilizing are transcritical in order to reach the required temperatures for heat rejection from the gas cooler. Additionally, cycles with expansion work recovery and an ejector are compared. The cooling requirements are up to 150 kW with a heat source temperature as low as and a heat sink temperature of up to . The purpose of this analysis is to understand which of the above cycles performs with the highest efficiency for the given electronics cooling application

    A Dynamic Model Of A Vapor Compression Liquid Chiller

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    Recovery of Waste Thermal Energy in U.S. Residential Appliances

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    With the United States being the world’s second largest consumer of primary energy, research into areas of significant consumption can provide large impacts in terms of the global energy consumption. Buildings account for 41% of US total energy consumption with the residential sector making up a majority. Household appliances account for the second largest site energy consumption at 27%, after the HVAC system for the U.S. residential sector. By quantifying the expected energy available in the waste stream for five major appliances; household refrigerator, clothes dryer and washer, dishwasher, and cooking oven, a potential energy source is presented. A cold water cooling stream is applied to the waste stream of each appliance and an estimated amount of energy can be recovered. The household refrigerator is modeled having an increase in cooling capacity of about 12% and a reduction on compressor power consumption of about 26%. A sample operation of the clothes dryer has the exhaust air stream being cooled down to 30.5°C (86.9°F) or on the other side, is able to heat 19 liter (5 gal) of water up to about 54.5°C (130.1°F). Large volumes of water are available by the clothes washer, but due to typical operation characteristics, low wash and rinse temperatures, the waste stream was not high in temperature. While the dishwasher provided higher heat source temperatures, 40°C (104°F), than the clothes washer, 36°C (97°F), the opposite was true. The volume of waste water drained is very low compared to the clothes washer 11.7 liter (3.1 gal) to 155 liter (41 gal). Thus water temperatures in the storage tank did not reach above 30°C (86°F) even with low storage volumes. The cooking oven can generate very high water temperatures depending how small of a storage tank is connected. Further work in this area is recommended due to the potential of high water temperatures generated from residential waste energy streams not currently being captured, and thus can offset some site-energy usage
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