Representing Roomates' Preferences with Symmetric Utilities

In the context of the stable roommates problem, it is shown that acyclicity of preferences is equivalent to the existence of symmetric utility functions, i.e. the utility of agent i when matched with j is the same as j 's utility when matched with i .

Where is the value in high frequency trading?.

We analyze the impact of high frequency trading in financial markets based on a model with three types of traders: liquidity traders, market makers, and high frequency traders. Our four main findings are: i) The price impact of the liquidity trades is higher in the presence of the high frequency trader and is increasing with the size of the trade. In particular, we show that the high frequency trader reduces (increases) the prices that liquidity traders receive when selling (buying) their equity holdings. ii) Although market makers also lose revenue to the high frequency trader in every trade, they are compensated for these losses by a higher liquidity discount. iii) High frequency trading increases the volatility of prices. iv) The volume of trades doubles as the high frequency trader intermediates all trades between the liquidity traders and market makers. This additional volume is a consequence of trades which are carefully tailored for surplus extraction and are neither driven by fundamentals nor is it noise trading. In equilibrium, high frequency trading and traditional market making coexist as competition drives down the profits for new high frequency traders while the presence of high frequency traders does not drive out traditional market makersHigh frequency traders; High frequency trading; Flash trading; Liquidity traders; Institutional investors; Market microstructure;

Evaluating Hospital Efficiency Adjusting for Quality Indicators: an Application to Portuguese NHS Hospitals

The objective of this paper is to develop a methodology to incorporate measures of hospital quality in efficiency analysis, applied to Portuguese NHS hospitals, in order to assess whether there is a trade-off between efficiency and quality in Portuguese hospitals. We develop and compare two methodologies to compute DEA technical efficiency scores adjusted for output quality, for a sample of Portuguese NHS hospitals in 2009. When DEA efficiency scores are adjusted for output quality, the decision making units that lie on the technical efficiency frontier remain largely unaltered, even if a great weight is given to quality indicators over quantity indicators of output. Nevertheless, we find that outside of the frontier adjusting for quality does have an impact in efficiency scores.We conclude that the empirical evidence is not sufficient to identify a clear trade-off between efficiency and quality in the hospitals under review, implying the possibility that efficiency gains may achieved without a significant sacrifice of service quality. Nevertheless, there is enough evidence to conclude that analyzing hospital efficiency without consideration of differences in quality of service will generate biased results. When perceived quality is brought to the analysis, the gap between efficient and inefficient units tends to widen.Hospital efficiency, Hospital quality, Data Envelopment Analysis

The Wall between Latinas and Latinos? Gender and Immigration Enforcement Attitudes among U.S. Latina/o Voters

Donald Trump’s surprising level of support among U.S. Latina/o voters in 2016 and his improved performance in the 2020 election posed a puzzle for Latina/o politics scholars given his stridently anti-immigrant agenda. Although scholars have acknowledged the political gender gap between Latinas and Latino men, few studies have outlined the theoretical basis or explored the empirical existence of gender differences in Latina/o immigration enforcement attitudes. Building on the Latina politics literature documenting Latinas’ greater engagement in solidarity work with immigrants and their greater desire for cultural transmission and the maintenance of pan-ethnic identity, I test two hypotheses. The first (the Latina/o gender hypothesis) postulates that Latinas will exhibit more liberal attitudes on matters of immigration enforcement relative to Latino men. The second (the immigrant identity hypothesis) postulates that Latinas are more likely to rely on their sense of commonality with immigrants in the formation of their immigration enforcement attitudes. Bivariate and multivariate analyses of the 2020 Collaborative Multiracial Postelection Survey support both hypotheses, which suggests not only that immigration attitudes among Latinas and Latino men are meaningfully distinct, but also that there are important structural differences underlying Latina/o beliefs in this policy area

Estimating surface flow based on the equation of heavy rain type LnLn / Estimativa do escoamento superficial baseado na equação de chuvas intensas do tipo LnLn

Runoff simulation is important in modeling various hydrological processes with application in agricultural engineering. The estimate of the surface runoff by the soil water balance method, developed by the Research Group on Water Resources at the Federal University of Viçosa, Brazil, is based on the IDF equation. This work aimed to adapt the methodology for use in locations with the LnLn-type equation. The equations for estimating the maximum instantaneous rainfall intensity and other adaptations for estimating the surface runoff were presented. Based on the intense rainfall equations of Piracicaba and Andradina, located in the state of São Paulo, Brazil, considering soils with a basic infiltration rate of 10, 25 and 50 mm.h-1, the values of the soil water balance method were presented. The results showed that the differences obtained are due only to errors in the estimation of rainfall intensity due to the method of adjusting the parameters of the intense rainfall equations and that the equations presented in this article allow the use of the maximum flow depth estimation method. surface water balance for sites with the LnLn type equation

Reflexión sobre el trabajo de la Universidad de las Regiones Autónomas de la Costa Caribe Nicaragüense (URACCAN) como universidad comunitaria intercultural

In Latin America and the Caribbean, several intercultural community universities have emerged promoted by indigenous people, Afro-descendants and other ethnic communities, with the enthusiasm of offering their communities an education of their own according to their cultures, ways of thinking, and ways of living, knowings and practices. In Nicaragua, URACCAN is one of them; However, the work of this type of universities has not been easy, due to the resistance of recognizing them as such, to the point that government authorities in some countries attack their existence, alleging lack of quality, promoting until closing in some cases. Therefore, it is important to share the work of intercultural community universities in a way that helps the community in general to know and recognize the importance of these universities. In this sense, this essay describes the work of URACCAN; showing the positive results that it has had both in its construction as an intercultural community public university and with the strengthening of the Nicaraguan Regional Autonomy and recognition at the international levelEn América Latina y el Caribe han surgido diversas universidades comunitarias interculturales promovidas por indígenas, afrodescendientes y otras comunidades étnicas con el entusiasmo de ofrecer a sus comunidades una educación propia acorde a sus culturas, formas de pensar, formas de vivir, saberes y prácticas. En Nicaragua la URACCAN es una de ellas; sin embargo, el trabajo de este tipo de universidades no ha sido fácil, debido a la resistencia de reconocerlas como tales, hasta el punto de que autoridades gubernamentales de algunos países ataquen su existencia, alegando la falta de calidad, promoviendo hasta el cierre en algunos casos. Por consiguiente, se hace importante compartir el trabajo que realizan las universidades comunitarias interculturales de manera que se contribuya a que la comunidad en general conozca y reconozca la importancia de estas universidades. En este sentido, en este ensayo se describe el quehacer de la URACCAN; mostrando los resultados positivos que ha tenido tanto en su construcción como universidad pública comunitaria intercultural como con el fortalecimiento de la Autonomía Regional Nicaragüense y el reconocimiento a nivel internaciona

Optimising Humanness: Designing the best human-like Bot for Unreal Tournament 2004

This paper presents multiple hybridizations of the two best bots on the BotPrize 2014 competition, which sought for the best humanlike bot playing the First Person Shooter game Unreal Tournament 2004. To this aim the participants were evaluated using a Turing test in the game. The work considers MirrorBot (the winner) and NizorBot (the second) codes and combines them in two different approaches, aiming to obtain a bot able to show the best behaviour overall. There is also an evolutionary version on MirrorBot, which has been optimized by means of a Genetic Algorithm. The new and the original bots have been tested in a new, open, and public Turing test whose results show that the evolutionary version of MirrorBot apparently improves the original bot, and also that one of the novel approaches gets a good humanness level.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Nuevas observaciones sobre el contorno definicional: a propósito de la fórmula dicho de en el DRAE 2001

Una de las innovaciones que en su día llamaron quizá más la atención en la última edición del Diccionario de la lengua española de la Real Academia Española (en adelante DRAE 2001) es sin duda el deslinde que se hace —si bien no en todos los casos— de contorno y definición, según se indica en las advertencias preliminares (p. XLIX): La consideración como propia de una definición depende en muchas ocasiones de la posibilidad de deslindar, dentro de ella, su contenido, es decir, el enunciado semánticamente definidor, distinguiéndolo de su contorno, es decir, de todos aquellos elementos que informan sobre el contexto —sintáctico, situacional, etc.— en que se presenta habitual-mente. En este Diccionario se independizan, mediante el uso de fórmulas como las ahora ejemplificadas, tradicionales en la lexicografía académica, distintos contornos de adjetivos y locuciones adjetivas, sujetos del verbo y de la frase, adverbios y locuciones adverbiales