4,486 research outputs found
Parton branching at amplitude level
We present an algorithm that evolves hard processes at the amplitude level by
dressing them iteratively with (massless) quarks and gluons. The algorithm
interleaves collinear emissions with soft emissions and includes
Coulomb/Glauber exchanges. It includes all orders in , is spin
dependent and is able to accommodate kinematic recoils. Although it is
specified at leading logarithmic accuracy, the framework should be sufficient
to go beyond. Coulomb exchanges make the factorisation of collinear and soft
emissions highly non-trivial. In the absence of Coulomb exchanges, we show how
factorisation works out and how a partial factorisation is manifest in the
presence of Coulomb exchanges. Finally, we illustrate the use of the algorithm
by deriving DGLAP evolution and computing the resummed thrust, hemisphere jet
mass and gaps-between-jets distributions in .Comment: 54 pages, minor changes in version
The design of incentives for health care providers in developing countries : contracts, competition, and cost control
The authors examine the design and limitations of incentives for health care providers to serve in rural areas in developing countries. Governments face two problems: it is costly to compensate well-trained urban physicians enough to relocate to rural areas, and it is difficult to ensure quality care when monitoring performance is costly or impossible. The goal of providing universal primary health care has been hard to meet, in part because of the difficulty of staffing rural medical posts with conscientious caregivers. The problem is providing physicians with incentives at a reasonable cost. Governments are often unable to purchase medical services of adequate quality even from civil servants. Using simple microeconomic models of contracts and competition, the authors examine questions about: a) The design of rural service requirements and options for newly trained physicians. b) The impact of local competition on the desirable level of training for new doctors. c) The incentive power that can be reasonably expected from explicit contracts. One problem a government faces is choosing how much training to give physicians it wants to send to rural areas. Training is costly, and a physician relocated to the countryside is outside the government's direct control. Should rural doctors face a ceiling on the prices they charge patients?Can it be enforced? The authors discuss factors to consider in determining how to pay rural medical workers but conclude that we might have to set realistic bounds on our expectations about delivering certain kinds of services. If we can identify reasons why the best that can be expected is not a particularly good, it might lead us to explore entirely different policy systems. Maybe it is too hard to run certain decentralized systems. Maybe we should focus on less ambitious but more readily achievable goals, such as providing basic infrastructure.
Cost-Efficient Valuation of Aesthetic Amenities
In order to avoid costly data collection practices common in hedonic valuation of aesthetic amenities, easy-to-collect secondary County tax and geospatial data are used to derive estimates for spatial effects on residential land values. Three Georgia Counties were selected due to data availability: Clarke, Henry, and Richmond. All properties meeting panel-design criterion are included in analysis samples. Large datasets prompt the omission of traditional hedonic model variables such as property characteristics. The focus of analysis is directed toward Canopy and Impervious land-cover estimates. Focal means are calculated at different ranges for immediate and neighborhood-wide assessment of surrounding cover. Community variables designed to describe neighborhood composition are included. Class, the measure of average size and Density, the average distance between nearby homes, are calculated at same neighborhood ranges as Focal means. Regressors also include distances to Schools, Hospitals, Airports, and Highways. Pooled Ordinary Least Squares performed with data normalized by log-transformation yields practical, statistically significant results. Consistency of estimates among Counties provides assurance of model viability, while variety is still strong between all Counties. Some concerns of data reliability and appropriateness of goodness-of-fit measure are voiced for any future analysis.Land Economics/Use,
Use of Algal and Macroinvertebrate Indicators to Assess the Impact of Agricultural Practices on Surface Water Quality in the Mammoth Cave National Park Region, Kentucky
The karst aquifer underlying the Mammoth Cave area supports a unique and diverse cave aquatic ecosystem as well as providing the principal source of drinking water for many local residents of the region. This unique and fragile ecosystem is surrounded by one of the most intensively used agricultural areas in the Commonwealth with more than 80% of the surrounding region used in beef, dairy, burley tobacco and alfalfa production. Agricultural practices resulting in run-off of pollutants into the aquifer via sinkholes and sinking streams have a pronounced impact on an important drinking water source and on the cave ecosystem. The purpose of this project was to determine if applying biofiltered effluent on fields was having a deliterious effect on Buck Creek. Based on the results, there is impact but not impairment
Irish Representations in the Films of Jim Sheridan and Neil Jordan
This thesis explores four films from second wave directors Jim Sheridan and Neil Jordan: The Crying Game, The Butcher Boy, The Field, and The Boxer. In these films, Sheridan and Jordan add complexity to previously static film representations of Irish society and culture. The study analyzes the modifications Sheridan and Jordan make to the cultural and political representations of the first wave of Irish films, relating theoretical developments more traditionally used in literary studies, including postcolonialism and postmodernism. It also explores how these four films have influenced more recent developments in Irish cinema, including the recent shifting of the settings for Irish films to more international settings exemplified by Sheridan’s recent film, the Oscar-nominated In America
Characterization of the developing facial and hypoglossal motor systems in the neonatal Brazilian opossum
Aspects of development of the facial and hypoglossal motor systems were investigated in the neonatal Brazilian opossum, Monodelphis domestica. Monodelphis is a small pouchless marsupial whose young are born after 14 days of gestation in an extremely immature state while neurogenesis is still ongoing;1. The developmental time course for synaptogenesis in the facial motor nucleus (FMN) and the hypoglossal motor nucleus (HMN) was examined using immunohistochemistry against: synaptic vesicle-associated proteins, synaptophysin and synaptotagmin; a synaptic membrane protein, SNAP-25; a growth cone protein, GAP-43; and microtubule-associated proteins, Tau-1 and MAP-2. We found that appearance of synapse-associated proteins is delayed in the FMN as compared to the HMN during the first two weeks of postnatal life;2. To examine the postnatal development of the FMN and HMN we utilized retrograde tract tracing with cholera toxin subunit B (CtB). On the day of birth (1 PN), CtB labeled facial motoneurons were localized near the developing abducens nucleus. From 3 to 5 PN facial motoneurons were observed migrating to the FMN, and by 7 to 10 PN facial motoneurons had completed their migration. In contrast, CtB-labeled hypoglossal motoneurons were localized within the HMN from birth onward. Migrating facial motoneurons displayed a bipolar shape characteristic of migrating neurons, their rate of migration was faster than the rate of brainstem expansion, and they were localized in close proximity of vimentin immunostained radial glial fibers previously shown to guide migrating neurons;3. Utilizing immunohistochemistry against choline acetyltransferase, neurofilament, and synaptotagmin we demonstrated that both facial and hypoglossal motoneuron projections extend to their respective target muscles and appear to innervate them from the day of birth. These results suggest that facial and hypoglossal motoneurons innervate their target muscles at birth, during the period of facial motoneuron migration. Further, the FMN does not have synaptic or classical afferent innervation during this period. We suggest that the activity of facial motoneurons is regulated in a novel or distinct manner compared to hypoglossal motoneurons during this period of brain development
The Effect of Campaign Spending in Missouri State Legislative Elections 1998-2006 [abstract]
Abstract only availableExamining all Missouri state House and Senate elections 19982-2006, I find that campaign spending has a minimal impact on the outcome of elections. Using fixed-effects panel data regression, controlling for incumbency, party, quality of challenger, the presence of third parties, year, and district partisanship, the effects of spending.David Loschky Memorial Scholarshi
Ihara’s Lemma for Shimura curves over totally real fields via patching
We prove Ihara’s lemma for the mod l cohomology of Shimura curves, localized at a maximal ideal of the Hecke algebra, under a large image hypothesis on the associated Galois representation. This was proved by Diamond and Taylor, for Shimura curves over Q, under various assumptions on l. Our method is totally different and can avoid these assumptions, at the cost of imposing the large image hypothesis. It uses the Taylor–Wiles method, as improved by Diamond and Kisin, and the geometry of integral models of Shimura curves at an auxiliary prime
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