A Non-Parametric Approach to Spatial Causality

The purpose of this paper is to show the capacity of a new non-parametric test based on symbolic entropy and symbolic dynamics to deal with the detection of linear and non-linear spatial causality. The good performance of the new test in detecting spatial causality and causal weighting matrix is notable and gives rise to an expectation that it may form a adequate tool for constructive specification searches.Causality; Spatial Dependence; Spatial Weight Matrices

Hardiness levels of professional spanish firefighters

Personality trait

Six years of sick leave spells in a group of university civilworkers. Can modernwork bring them a new health problem?

The objective of this study is to analyse sick leave episodes of a university’s collective of statutory workers in the State of São Paulo, between January 2010 and December 2015. For this, a descriptive study analysed 5776 registered spells of sick leave of four university units: agricultural sciences; human health, health and animal reproduction, and biological sciences; an administrative unit; and a university hospital. The medical expert assessment was carried out by general practitioners and psychiatrists who managed sick leave and return to work cases. Around 52% had up to three sick leave episodes, and 10% of the workers had 20 or more episodes. Each spell of sickness absence lasted a median of 30 days (IQR 8–60 days). Among all of sick leaves, 35% had as a primary cause mental or behavioural diseases, of which 30% were depressive disorders, followed by around 18% related to the musculoskeletal system and the connective tissues. In the medical reports, 80% of the workers reported pain and 30% reported psychological symptoms. The collective, seen as privileged by many for their job stability, has a high percentage of sick leave due to mental illness, with extended periods which affect the levels of disability and reduce possibilities of return

Laparoscopic and robot-assisted laparoscopic digestive surgery: Present and future directions

Laparoscopic surgery is applied today worldwide to most digestive procedures. In some of them, such as cholecystectomy, Nissen’s fundoplication or obesity surgery, laparoscopy has become the standard in practice. In others, such as colon or gastric resection, the laparoscopic approach is frequently used and its usefulness is unquestionable. More complex procedures, such as esophageal, liver or pancreatic resections are, however, more infrequently performed, due to the high grade of skill necessary. As a result, there is less clinical evidence to support its implementation. In the recent years, robot-assisted laparoscopic surgery has been increasingly applied, again with little evidence for comparison with the conventional laparoscopic approach. This review will focus on the complex digestive procedures as well as those whose use in standard practice could be more controversial. Also novel robot-assisted procedures will be updated

Detección de Dependencia Espacial mediante Análisis Simbólico

Testing for the assumption of independence between spatial variables is an important first step in spatial conometrics. Usually the researchers use the bivariate generalization of the Moran’s statistic, specifying a spatial matrix a priori. This test is applicable only to detect linear relations in pairs of variables, which must be spatially non-autocorrelated. We develop a new non-parametric test, based on symbolic dynamics, that is free of these shortcomings. The test is consistent, computationally simple to obtain and powerful as shown in our Monte Carlo experiment

A los adolescentes que no les gusta la educación física tienen peor condición física y más obesidad ¿Mito o realidad? Los estudios AVENA y UP&DOWN

Introduction: In the physical education context a well-known myth suggest that obese and unfit youth dislike physical education. Objective: To examine if adolescents who dislike physical education have higher levels of fatness and lower of fitness than their peers. Methods: Participants included 2606 (49.3% girls) adolescents from AVENA and UP&DOWN studies. physical education enjoyment was assessed with a 7-point Likert scale. Fatness was assessed with BMI, skinfolds and waist circumference. Physical fitness was assessed with cardiorespiratory, motor and muscular fitness tests. Results: Boys who dislike physical education had similar levels of fatness and fitness than their peers (all P>0.05). Adolescent girls who dislike physical education had higher levels in body fat (P=0.035), and lower levels in muscular (P=0.007) and motor (P=0.007) fitness than their peers. Conclusion: Since only girls who dislike physical education seem to have, albeit weak, higher levels of fatness and lower of fitness than their peers, it partially confirms the myth in adolescent girls.Introducción: En el contexto de la EF (educación física), un mito bien conocido podría sugerir que a los jóvenes obesos y con baja condición física no les gusta la EF. Objetivo: Examinar si a los adolescentes a los que no les gusta la EF tienen niveles más altos de obesidad y niveles más bajos de forma física que sus compañeros. Métodos: Se tomó a 2606 participantes (49.3% chicas) adolescentes de los estudios AVENA y UP&DOWN. El disfrute de la EF se evaluó empleando una escala Likert de 7 puntos. La obesidad se evaluó mediante el IMC, pliegues cutáneos y circunferencia de la cintura. La condición física fue evaluada mediante pruebas cardiorespiratorias, motoras y musculares. Resultados: Los chicos a los que no les gusta la EF presentaron niveles similares de obesidad que sus compañeros (total P>0.05). Las chicas adolescentes a las que no les gusta la EF presentaron niveles más altos de grasa corporal (P=0.035), y niveles más bajos en condición física muscular (P=0.007) y motora (P=0.007) que sus compañeros. Conclusión: Dado que solo las chicas a las que no les gusta la EF parecen presentar, sin bien levemente, niveles más altos de obesidad y niveles menores de forma física que sus compañeros, el mito se confirma parcialmente para las chicas adolescentes.The AVENA study was supported by the Spanish Ministry of Health (FIS Nº 00/0015) and the UP&DOWN study was supported by the Spanish Ministry of Economy and Competitiveness (DEP 2010-21662-C04)

¿Cuál matriz de pesos espaciales?. Un enfoque sobre selección de modelos

In spatial econometrics, it is customary to specify a weighting matrix, the so-called W matrix. The decision is important because the choice of W matrix determines the rest of the analysis. However, the procedure is not well defined and, usually, reflects the priors of the user. In the paper, we revise the literature looking for criteria to help with this problem. Also, a new nonparametric procedure is introduced. Our proposal is based on a measure of the information, conditional entropy, that uses information present in the data. We compare these alternatives by means of a Monte Carlo experiment

Selecting the Most Adequate Spatial Weighting Matrix:A Study on Criteria

In spatial econometrics, it is customary to specify a weighting matrix, the so-called W matrix, by choosing one matrix from a finite set of matrices. The decision is extremely important because, if the W matrix is misspecified, the estimates are likely to be biased and inconsistent. However, the procedure to select W is not well defined and, usually, it reflects the judgments of the user. In this paper, we revise the literature looking for criteria to help with this problem. Also, a new nonparametric procedure is introduced. Our proposal is based on a measure of the information, conditional entropy. We compare these alternatives by means of a Monte Carlo experiment

Detecting dependence between spatial processes

Testing the assumption of independence between variables is a crucial aspect of spatial data analysis. However, the literature is limited and somewhat confusing. To our knowledge, we can mention only the bivariate generalization of Moran’s statistic. This test suffers from several restrictions: it is applicable only to pairs of variables, a weighting matrix and the assumption of linearity are needed; the null hypothesis of the test is not totally clear. Given these limitations, we develop a new non-parametric test based on symbolic dynamics with better properties. We show that the test can be extended to a multivariate framework, it is robust to departures from linearity, it does not need a weighting matrix and can be adapted to different specifications of the null. The test is consistent, computationally simple and with good size and power, as shown by a Monte Carlo experiment. An application to the case of the productivity of the manufacturing sector in the Ebro Valley illustrates our approach

Testing Spatial Causality in Cross-section Data

The paper shows a new non-parametric test, based on symbolic entropy, which permits detect spatial causality in cross-section data. The test is robust to the functional form of the relation and has a good behaviour in samples of medium to large size. We illustrate the use of test with the case of relationship between migration and unemployment, using data on 3,108 U.S. counties for the period 2003-2008