3,336 research outputs found
Axiomatic Bargaining Theory on Opportunity Assignments
This paper discusses issues of axiomatic bargaining problems over opportunity assignments. The fair arbitrator uses the principle of "equal opportunity" for all players to make the recommendation on re- source allocations. A framework in such a context is developed and several classical solutions to standard bargaining problems are reformulated and axiomatically characterized. Working Paper 06-4
Towards an Ontological Modelling of Preference Relations
Preference relations are intensively studied in Economics,
but they are also approached in AI, Knowledge Representation, and
Conceptual Modelling, as they provide a key concept in a variety of
domains of application. In this paper, we propose an ontological foundation
of preference relations to formalise their essential aspects across
domains. Firstly, we shall discuss what is the ontological status of the
relata of a preference relation. Secondly, we investigate the place of preference
relations within a rich taxonomy of relations (e.g. we ask whether
they are internal or external, essential or contingent, descriptive or nondescriptive
relations). Finally, we provide an ontological modelling of
preference relation as a module of a foundational (or upper) ontology
(viz. OntoUML).
The aim of this paper is to provide a sharable foundational theory of
preference relation that foster interoperability across the heterogeneous
domains of application of preference relations
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Modeling Flow and Transport Pathways to the Potential Repository Horizon at Yucca Mountain
The isotopic ratios of {sup 36}Cl/Cl are used in conjunction with geologic interpretation and numerical modeling to evaluate flow and transport pathways, processes, and model parameters in the unsaturated zone at Yucca Mountain. By synthesizing geochemical and geologic data, the numerical model results provide insight into the validity of alternative hydrologic parameter sets, flow and transport processes in and away from fault zones, and the applicability of {sup 36}Cl/Cl ratios for evaluating alternative conceptual models
Takeovers and cooperatives: governance and stability in non-corporate firms
Author's draft dated 11 January 2010. Final version published in Journal of economics available online at http://www.springerlink.com/If consumers wholly or partially control a firm with market power they
will charge less than the profit maximizing price. Starting at the usual monopoly
price, a small price reduction will have a second order effect on profits but a first order
effect on consumer surplus. Despite this desirable static result, it has been argued that
cooperatives are vulnerable to take-over by outsiders who will run them as for-profit
businesses. This paper studies takeovers of cooperatives. We argue that there will not
be excessive takeovers of cooperatives due to the Grossman-Hart problem of free
riding during takeovers.Research in part supported by ESRC grant RES-000-22-0650
Role of Bax in resveratrol-induced apoptosis of colorectal carcinoma cells
BACKGROUND: The natural plant polyphenol resveratrol present in some foods including grapes, wine, and peanuts, has been implicated in the inhibition, delay, and reversion of cellular events associated with heart diseases and tumorigenesis. Recent work has suggested that the cancer chemoprotective effect of the compound is primarily linked to its ability to induce cell division cycle arrest and apoptosis, the latter possibly through the activation of pro-apoptotic proteins such as Bax. METHODS: The expression, subcellular localization, and importance of Bax for resveratrol-provoked apoptosis were assessed in human HCT116 colon carcinoma cells and derivatives with both bax alleles inactivated. RESULTS: Low to moderate concentrations of resveratrol induced co-localization of cellular Bax protein with mitochondria, collapse of the mitochondrial membrane potential, activation of caspases 3 and 9, and finally, apoptosis. In the absence of Bax, membrane potential collapse was delayed, and apoptosis was reduced but not absent. Resveratrol inhibited the formation of colonies by both HCT116 and HCT116 bax -/- cells. CONCLUSION: Resveratrol at physiological doses can induce a Bax-mediated and a Bax-independent mitochondrial apoptosis. Both can limit the ability of the cells to form colonies
The fate of the homoctenids (Tentaculitoidea) during the Frasnian-Famennian mass extinction (Late Devonian)
The homoctenids (Tentaculitoidea) are small, conical-shelled marine animals which are amongst the most abundant and widespread of all Late Devonian fossils. They were a principal casualty of the Frasnian-Famennian (F-F, Late Devonian) mass extinction, and thus provide an insight into the extinction dynamics. Despite their abundance during the Late Devonian, they have been largely neglected by extinction studies. A number of Frasnian-Famennian boundary sections have been studied, in Poland, Germany, France, and the United States. These sections have yielded homoctenids, which allow precise recognition of the timing of the mass extinction. It is clear that the homoctenids almost disappear from the fossil record during the latest Frasnian “Upper Kellwasser Event”. The coincident extinction of this pelagic group, and the widespread development of intense marine anoxia within the water column, provides a causal link between anoxia and the F-F extinction. Most notable is the sudden demise of a group, which had been present in rock-forming densities, during this anoxic event. One new species, belonging to Homoctenus is described, but is not formally named here
Quantitative bone marrow lesion size in osteoarthritic knees correlates with cartilage damage and predicts longitudinal cartilage loss
<p>Abstract</p> <p>Background</p> <p>Bone marrow lesions (BMLs), common osteoarthritis-related magnetic resonance imaging findings, are associated with osteoarthritis progression and pain. However, there are no articles describing the use of 3-dimensional quantitative assessments to explore the longitudinal relationship between BMLs and hyaline cartilage loss. The purpose of this study was to assess the cross-sectional and longitudinal descriptive characteristics of BMLs with a simple measurement of approximate BML volume, and describe the cross-sectional and longitudinal relationships between BML size and the extent of hyaline cartilage damage.</p> <p>Methods</p> <p>107 participants with baseline and 24-month follow-up magnetic resonance images from a clinical trial were included with symptomatic knee osteoarthritis. An 'index' compartment was identified for each knee defined as the tibiofemoral compartment with greater disease severity. Subsequently, each knee was evaluated in four regions: index femur, index tibia, non-index femur, and non-index tibia. Approximate BML volume, the product of three linear measurements, was calculated for each BML within a region. Cartilage parameters in the index tibia and femur were measured based on manual segmentation.</p> <p>Results</p> <p>BML volume changes by region were: index femur (median [95% confidence interval of the median]) 0.1 cm<sup>3 </sup>(-0.5 to 0.9 cm<sup>3</sup>), index tibia 0.5 cm<sup>3 </sup>(-0.3 to 1.7 cm<sup>3</sup>), non-index femur 0.4 cm<sup>3 </sup>(-0.2 to 1.6 cm<sup>3</sup>), and non-index tibia 0.2 cm<sup>3 </sup>(-0.1 to 1.2 cm<sup>3</sup>). Among 44 knees with full thickness cartilage loss, baseline tibia BML volume correlated with baseline tibia full thickness cartilage lesion area (<it>r </it>= 0.63, <it>p</it>< 0.002) and baseline femur BML volume with longitudinal change in femoral full thickness cartilage lesion area (<it>r </it>= 0.48 <it>p</it>< 0.002).</p> <p>Conclusions</p> <p>Many regions had no or small longitudinal changes in approximate BML volume but some knees experienced large changes. Baseline BML size was associated to longitudinal changes in area of full thickness cartilage loss.</p
Measuring Group Disadvantage with Inter-Distributional Inequality Indices: A Critical Review and Some Amendments to Existing Indices
A long literature on inter-distributional inequality (IDI) has developed statistical tools for measuring the extent of inequality between two groups (e.g. men versus women). Firstly, I introduce the property of group-specific disadvantage focus (GDF). Indices satisfying this property are only sensitive to inequalities that are disadvantageous to one specific group. Then the paper reviews some of the most prominents IDI indices proposed in the last four decades. The assessment focuses on whether these indices satisfy GDF and, if not, how they react to inequalities that are disadvantageous to different groups. I also discuss whether these indices are informative, or not, regarding other interesting features related to IDI comparisons, e.g. distributional equality, absence of distributional overlap and presence of first-order stochastic dominance. Finally, I propose amendments to several of these indices in order to render them in fulfillment of GDF and more informative on the mentioned distributional features
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