College admissions and the role of information : an experimental study

We analyze two well-known matching mechanisms—the Gale-Shapley, and the Top Trading Cycles (TTC) mechanisms—in the experimental lab in three different informational settings, and study the role of information in individual decision making. Our results suggest that—in line with the theory—in the college admissions model the Gale-Shapley mechanism outperforms the TTC mechanisms in terms of efficiency and stability, and it is as successful as the TTC mechanism regarding the proportion of truthful preference revelation. In addition, we find that information has an important effect on truthful behavior and stability. Nevertheless, regarding efficiency, the Gale-Shapley mechanism is less sensitive to the amount of information participants hold

College Admissions and the Role of Information: An Experimental Study

We analyze two well-known matching mechanisms\the Gale-Shapley, and the Top Trading Cycles (TTC) mechanisms\in theexperimental lab in three different informational settings, and study the role of information in individual decision making. Our results suggest that\in line with the theory\in the college admissions model the Gale-Shapley mechanism outperforms the TTC mechanisms in terms of efficiency and stability, and it is as successful as the TTC mechanism regarding the proportion of truthful preference revelation. In addition, we find that information has an important effect on truthful behavior and stability. Nevertheless, regarding efficiency, the Gale-Shapley mechanism is less sensitive to the amount of information participants hold.

College admissions and the role of information : an experimental study

We analyze two well-known matching mechanisms—the Gale-Shapley, and the Top Trading Cycles (TTC) mechanisms—in the experimental lab in three different informational settings, and study the role of information in individual decision making. Our results suggest that—in line with the theory—in the college admissions model the Gale-Shapley mechanism outperforms the TTC mechanisms in terms of efficiency and stability, and it is as successful as the TTC mechanism regarding the proportion of truthful preference revelation. In addition, we find that information has an important effect on truthful behavior and stability. Nevertheless, regarding efficiency, the Gale-Shapley mechanism is less sensitive to the amount of information participants hold.Experiments, Information, Matching

Effect of the Gribov horizon on the Polyakov loop and vice versa

We consider finite temperature SU(2) gauge theory in the continuum formulation, which necessitates the choice of a gauge fixing. Choosing the Landau gauge, the existing gauge copies are taken into account by means of the Gribov-Zwanziger (GZ) quantization scheme, which entails the introduction of a dynamical mass scale (Gribov mass) directly influencing the Green functions of the theory. Here, we determine simultaneously the Polyakov loop (vacuum expectation value) and Gribov mass in terms of temperature, by minimizing the vacuum energy w.r.t. the Polyakov loop parameter and solving the Gribov gap equation. Inspired by the Casimir energy-style of computation, we illustrate the usage of Zeta function regularization in finite temperature calculations. Our main result is that the Gribov mass directly feels the deconfinement transition, visible from a cusp occurring at the same temperature where the Polyakov loop becomes nonzero. In this exploratory work we mainly restrict ourselves to the original Gribov-Zwanziger quantization procedure in order to illustrate the approach and the potential direct link between the vacuum structure of the theory (dynamical mass scales) and (de)confinement. We also present a first look at the critical temperature obtained from the Refined Gribov-Zwanziger approach. Finally, a particular problem for the pressure at low temperatures is reported.Comment: 19 pages, 8 .pdf figures. v2: extended section 3 + extra references; version accepted for publication in EPJ

Double non-perturbative gluon exchange: an update on the soft Pomeron contribution to pp scattering

We employ a set of recent, theoretically motivated, fits to non-perturbative unquenched gluon propagators to check in how far double gluon exchange can be used to describe the soft sector of pp scattering data (total and differential cross section). In particular, we use the refined Gribov--Zwanziger gluon propagator (as arising from dealing with the Gribov gauge fixing ambiguity) and the massive Cornwall-type gluon propagator (as motivated from Dyson-Schwinger equations) in conjunction with a perturbative quark-gluon vertex, next to a model based on the non-perturbative quark-gluon Maris-Tandy vertex, popular from Bethe-Salpeter descriptions of hadronic bound states. We compare the cross sections arising from these models with "older" ISR and more recent TOTEM and ATLAS data. The lower the value of total energy \sqrt{s}, the better the results appear to be.Comment: 14 pages, 8 .pdf figures. To appear in Phys.Rev.

Cavilha cefalomedular antirrotativa versus placa e parafuso dinâmico no tratamento de fraturas trocantéricas instáveis da anca.

As fraturas da extremidade superior do fémur, nomeadamente as fraturas trocantéricas, continuam a representar um sério problema de saúde pública em idosos com osteoporose, presentando um elevado índice de morbilidade e mortalidade, apesar dos avanços registados tanto na sua prevenção como no seu tratamento. Apenas o tratamento cirúrgico pode permitir uma marcha e uma recuperação funcional precoces, por forma que o doente consiga uma autonomia próxima da anterior à lesão. Para isso, o ortopedista dispõe atualmente de um leque alargado de implantes cirúrgicos que não tem, todavia, o mesmo valor e indicações, estando na dependência da “personalidade da fratura”. O objetivo central deste trabalho foi determinar, através de um estudo comparativo, os resultados radiológicos, clínicos e ortopédicos de uma série de 116 fraturas trocantéricas instáveis do fémur (AO 31 A2), em que se utilizaram dois tipos diferentes de implantes, a cavilha cefaloendomedular antirrotativa (PFNA®) e placa e parafuso dinâmico (DHS®). Foram analisados os registos clínicos de 116 doentes com fraturas trocantéricas instáveis, com um tempo de recuo igual ou superior a 12 meses. 66 casos foram tratados com DHS® e os restantes 50 com PFNA®. Procedeu-se ao registo do tempo operatório, do tempo de internamento, do tipo e qualidade da redução da fratura, do tempo de consolidação da fratura, da necessidade de transfusão sanguínea e das complicações clínicas e ortopédicas. Os dados obtidos foram sujeitos a um estudo estatístico usando o programa SPSS - Statistical Package for Social Sciences, versão 22.0 para Windows. Considerando a totalidade das fraturas 31 A2, o DHS® apresentou taxas superiores de reduções das fraturas consideradas insatisfatórias (23,4% e 18,0% para DHS® e PFNA®, respetivamente) e de complicações clínicas (34,8% e 32,0% para DHS® e PFNA®, respetivamente) e ortopédicas (15,2% e 14,0% para DHS® e PFNA®, respetivamente). O tempo de cirurgia, a necessidade de transfusão sanguínea (53,0% e 68,0% para DHS® e PFNA®, respectivamente) e a proporção de reduções das fraturas consideradas anatómicas (21,9% e 36,0% para DHS® e PFNA®, respectivamente) foi superior no grupo do PFNA®. O tempo de internamento e as taxas de consolidação foram semelhantes nos dois tipos de implante. Restringindo a análise apenas para o tipo específico de fraturas 31 A2.2., alguns resultados estatísticos sofreram alterações. As taxas de complicações clínicas (20,7% e 14,3% para DHS® e PFNA®, respectivamente) e ortopédicas (37,9% e 31,0% para DHS® e PFNA®, respetivamente) acentuaram-se no grupo do DHS®, com taxas de transfusão (69,0% e 64,3% para DHS® e PFNA®,respetivamente) semelhantes em ambos os grupos. No tratamento das fraturas trocantéricas instáveis da anca (31 A2.2) o PFNA® mostrou ser superior ao DHS®, em termos da qualidade de redução da fratura e nas taxas de complicações clínicas e ortopédicas. Nas estantes variáveis, o PFNA® não mostrou resultados inferiores

Decentralized matching markets with(out) frictions : a laboratory experiment

In a series of laboratory experiments, we explore the impact of different market features (the level of information, search costs, and the level of commitment) on agents’ behavior and on the outcome of decentralized matching markets. In our experiments, subjects on each side of the market actively search for a partner, make proposals, and are free to accept or reject any proposal received at any time throughout the game. Our results suggest that a low information level does not affect the stability or the efficiency of the final outcome, although it boosts market activity, unless coupled with search costs. Search costs have a significant negative impact on stability and on market activity. Finally, commitment harms stability slightly but acts as a disciplinary device to market activity and is associated with higher efficiency levels of the final outcome.info:eu-repo/semantics/publishedVersio

Decentralized matching markets : a laboratory experiment

We report data from controlled laboratory experiments on two-sided matching markets in which participants interact in a decentralized way, without having to refer to a central clearinghouse. Our treatments have been designed to evaluate the effect of information, search costs, and binding agreements on the final outcome and also on the individual strategies that lead to it. We find that these features affect the level and pace of market activity as well as the identity of those who receive proposals. While the lack of information alone does not reduce stability or efficiency, its combination with search costs can be detrimental.Financial support from Fundação para a Ciência e Tecnologia (FCCN); Juan de la Cierva program of the Spanish Ministry of Science and Innovation

Decentralized matching markets with(out) frictions : a laboratory experiment

In a series of laboratory experiments, we explore the impact of different market features (the level of information, search costs, and the level of commitment) on agents’ behaviour and on the outcome of decentralized matching markets. In our experiments, subjects on each side of the market actively search for a partner, make proposals, and are free to accept or reject any proposal received at any time throughout the game. Our results suggest that a low information level boosts market activity but does not affect stability or efficiency of the final outcome, unless coupled with search costs. Search costs have a significant negative impact on market activity, and on both stability and efficiency. Finally, commitment harms stability slightly but acts as a disciplinary device to market activity and is associated with higher efficiency levels of the final outcome.info:eu-repo/semantics/publishedVersio