3,600 research outputs found
CONVEGNO LA RICERCA PER L’AGRICOLTURA BIOLOGICA E BIODINAMICA: UNA VISIONE DI INSIEME
This Conference was organized by the Italian Ministry of Agriculture and was aimed to an overview of the Research in Organic Farming in Italy.
This event was adapted for the presentation of FAVORDENONDE Project
Existence of Equilibrium Prices for Discontinuous Excess Demand Correspondences
The aim of the paper is to obtain the existence of equilibrium prices in economies where the excess demand correspondences—differently from the usual condition—are not necessarily upper semicontinuous. So, in our setting, we cannot use the Gale-Debreu-Nikaido Lemma. The existence of equilibrium prices is obtained for discontinuous excess demand correspondences which obey to a condition like of the weak axiom of reveled preferences.Discontinuous excess demand correspondences, existence of equilibrium prices, weak axiom of revealed preferences
Approximate social nash equilibria and applications
In this paper, a concept of approximate social Nash equilibria is considered and an existence result is given when the strategic spaces of the players are not compact. These have been obtained using an approximate fixed point theorem. As an application of the existence of such approximate social Nash equilibria, sufficient conditions for the existence of a suitable approximate walrasian equilibrium in finite economies are obtained. Among others things, it is shown that the approximate walrasian equilibrium here considered is approximatively weakly efficient.Abstract economy, approximate social Nash equilibrium, finite economy, approximate walrasian equilibrium, approximate fixed point theorems.
Data science of stroke imaging and enlightenment of the penumbra.
Imaging protocols of acute ischemic stroke continue to hold significant uncertainties regarding patient selection for reperfusion therapy with thrombolysis and mechanical thrombectomy. Given that patient inclusion criteria can easily introduce biases that may be unaccounted for, the reproducibility and reliability of the patient screening method is of utmost importance in clinical trial design. The optimal imaging screening protocol for selection in targeted populations remains uncertain. Acute neuroimaging provides a snapshot in time of the brain parenchyma and vasculature. By identifying the at-risk but still viable penumbral tissue, imaging can help estimate the potential benefit of a reperfusion therapy in these patients. This paper provides a perspective about the assessment of the penumbral tissue in the context of acute stroke and reviews several neuroimaging models that have recently been developed to assess the penumbra in a more reliable fashion. The complexity and variability of imaging features and techniques used in stroke will ultimately require advanced data driven software tools to provide quantitative measures of risk/benefit of recanalization therapy and help aid in making the most favorable clinical decisions
Major League Baseball\u27s Antitrust Exemption and the Impact of the Curt Flood Act
For many years, professional baseball has enjoyed a privileged antitrust exemption apart from other professional sports. With the passing of the Curt Flood Act in 1998 this exemption was removed; however, the act may not be as influential as it seems. Court rulings were prominent in initiating and maintaining the antitrust exemption for professional baseball. These include the Supreme Court Trilogy, especially the case of Curt Flood, a baseball player who fought against the reserve clause system which limited his and other players’ employment options. Collective bargaining as well as arbitration became dominant in professional baseball labor relations under the jurisdiction of the National Labor Relations Board and the National Labor Relations Act. Although the collective bargaining process in Major League Baseball has been contentious, it provided more bargaining power to the players, resulting in the elimination of many unfair labor practices including the reserve system. The Curt Flood Act of 1998, which allows professional Major League Baseball players to file lawsuits under antitrust regulations, served as the final step in equalizing the power between players and owners. Early predictions about the act concluded that it would either help strengthen baseball’s antitrust exemption or harm the collective bargaining process. Other researchers thought that the act would not have much of an effect at all because of its limitations and requirements. But others have noted some positive results, specifically in labor negotiations between players and owners, which point to the act having a genuine influence on Major League Baseball
Approximate Fixed Point Theorems in Banach Spaces with Applications in Game Theory
In this paper some new approximate fixed point theorems for multifunctions in Banach spaces are presented and a method is developed indicating how to use approximate fixed point theorems in proving the existence of approximate Nash equilibria for non-cooperative games.Nash equilibrium;noncooperative games
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Performance Comparison of Knowledge-Based Dose Prediction Techniques Based on Limited Patient Data.
PurposeThe accuracy of dose prediction is essential for knowledge-based planning and automated planning techniques. We compare the dose prediction accuracy of 3 prediction methods including statistical voxel dose learning, spectral regression, and support vector regression based on limited patient training data.MethodsStatistical voxel dose learning, spectral regression, and support vector regression were used to predict the dose of noncoplanar intensity-modulated radiation therapy (4π) and volumetric-modulated arc therapy head and neck, 4π lung, and volumetric-modulated arc therapy prostate plans. Twenty cases of each site were used for k-fold cross-validation, with k = 4. Statistical voxel dose learning bins voxels according to their Euclidean distance to the planning target volume and uses the median to predict the dose of new voxels. Distance to the planning target volume, polynomial combinations of the distance components, planning target volume, and organ at risk volume were used as features for spectral regression and support vector regression. A total of 28 features were included. Principal component analysis was performed on the input features to test the effect of dimension reduction. For the coplanar volumetric-modulated arc therapy plans, separate models were trained for voxels within the same axial slice as planning target volume voxels and voxels outside the primary beam. The effect of training separate models for each organ at risk compared to all voxels collectively was also tested. The mean squared error was calculated to evaluate the voxel dose prediction accuracy.ResultsStatistical voxel dose learning using separate models for each organ at risk had the lowest root mean squared error for all sites and modalities: 3.91 Gy (head and neck 4π), 3.21 Gy (head and neck volumetric-modulated arc therapy), 2.49 Gy (lung 4π), and 2.35 Gy (prostate volumetric-modulated arc therapy). Compared to using the original features, principal component analysis reduced the 4π prediction error for head and neck spectral regression (-43.9%) and support vector regression (-42.8%) and lung support vector regression (-24.4%) predictions. Principal component analysis was more effective in using all/most of the possible principal components. Separate organ at risk models were more accurate than training on all organ at risk voxels in all cases.ConclusionCompared with more sophisticated parametric machine learning methods with dimension reduction, statistical voxel dose learning is more robust to patient variability and provides the most accurate dose prediction method
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