On the dimension of the core of the assignment game

The set of optimal matchings in the assignment matrix allows to define a reflexive and symmetric binary relation on each side of the market, the equal-partner binary relation. The number of equivalence classes of the transitive closure of the equal-partner binary relation determines the dimension of the core of the assignment game. This result provides an easy procedure to determine the dimension of the core directly from the entries of the assignment matrix and shows that the dimension of the core is not as much determined by the number of optimal matchings as by their relative position in the assignment matrix.

Single-valued solutions for the Böhm-Bawerk horse market game

Single-valued solutions for the case of two-sided market games without product differentiation, also known as Böhm-Bawerk horse market games, are analyzed. The nucleolus is proved to coincide with the tau-value, and is thus the midpoint of the core. Moreover a characterization of this setof games in terms of the assignment matrix is provided.

An axiomatization of the nucleolus of the assignment game

[cat] En el domini dels jocs bilaterals d’assignació, es presenta una axiomàtica del nucleolus com l´unica solució que compleix les propietats de consistència respecte del joc derivat definit per Owen (1992) i monotonia de les queixes dels sectors respecte de la seva cardinalitat. Com a conseqüència obtenim una caracterització geomètrica del nucleolus mitjançant una propietat de bisecció més forta que la que satisfan els punts del kernel (Maschler et al, 1979).

A note on the coincidence between Stackelberg and Nash equilibria in a differential game between government and firms

[cat] A Navas i Marín Solano es va demostrar la coincidència entre els equilibris de Nash i de Stackelberg per a una versi´o modificada del joc diferencial proposat por Lancaster (1973). Amb l’objectiu d’obtenir una solució interior, es van imposar restriccions importants sobre el valors dels paràmetres del model. En aquest treball estenem aquest resultat, en el límit en que la taxa de descompte és igual a zero, eliminant les restriccions i considerant totes les solucions possibles.

The assignment game: core bounds for mixed-pair coalitions

In the assignment game framework, we try to identify those assignment matrices in which no entry can be increased without changing the coreof the game. These games will be called buyer¿seller exact games and satisfy the condition that each mixed¿pair coalition attains the corresponding matrix entry in the core of the game. For a given assignment game, a unique buyerseller exact assignment game with the same core is proved to exist. In order to identify this matrix and to provide a characterization of those assignment games which are buyer¿seller exact in terms of the assignment matrix, attainable upper and lower core bounds for the mixed¿pair coalitions are found. As a consequence, an open question posed in Quint (1991) regarding a canonical representation of a ¿45o¿lattice¿ by means of the core of an assignment game can now be answered

Video analysis software increases the interrater reliability of video gait assessments in children with cerebral palsy.

The aim of this study was to determine the effect of using video analysis software on the interrater reliability of visual assessments of gait videos in children with cerebral palsy. Two clinicians viewed the same random selection of 20 sagittal and frontal video recordings of 12 children with cerebral palsy routinely acquired during outpatient rehabilitation clinics. Both observers rated these videos in a random sequence for each lower limb using the Observational Gait Scale, once with standard video software and another with video analysis software (Dartfish(®)) which can perform angle and timing measurements. The video analysis software improved interrater agreement, measured by weighted Cohen's kappas, for the total score (κ 0.778→0.809) and all of the items that required angle and/or timing measurements (knee position mid-stance κ 0.344→0.591; hindfoot position mid-stance κ 0.160→0.346; foot contact mid-stance κ 0.700→0.854; timing of heel rise κ 0.769→0.835). The use of video analysis software is an efficient approach to improve the reliability of visual video assessments.

Video-assisted thoracic surgery diagnosis of thoracic spinal tuberculosis.

Tuberculous spondylitis is rare in economically well-developed countries. MRI is the most sensitive radiologic method of diagnosis. CT-guided fine needle aspiration can be an appropriate method for obtaining samples for culture, with positive cultures in 25 to 89% of cases. However, it can take >6 weeks for specimens to grow, and it is essential to have adequate culture and sensitivity studies for the diagnosis and treatment of mycobacterial diseases. We propose a minimally invasive diagnostic approach that ensures that adequate surgical specimens are obtained prior to initiating treatment.

Age vs. Experience: Evaluation of a Video Feedback Intervention for Newly Licensed Teen Drivers, TPF-5(207), 2013

This project examines the effects of age, experience, and video-based feedback on the rate and type of safety-relevant events captured on video event recorders in the vehicles of three groups of newly licensed young drivers: 1. 14.5- to 15.5-year-old drivers who hold a minor school license (see Appendix A for the provisions of the Iowa code governing minor school licenses); 2. 16-year-old drivers with an intermediate license who are driving unsupervised for the first time; 3. 16-year-old drivers with an intermediate license who previously drove unsupervised for at least four months with a school license. METHODS: The young drivers’ vehicles were equipped with an event-triggered video recording device for 24 weeks. Half of the participants received feedback regarding their driving, and the other half received no feedback at all and served as a control group. The number of safety-relevant events per 1,000 miles (i.e., “event rate”) was analyzed for 90 participants who completed the study. RESULTS: On average, the young drivers who received the video-based intervention had significantly lower event rates than those in the control group. This finding was true for all three groups. An effect of experience was seen for drivers in the control group; the 16-year-olds with driving experience had significantly lower event rates than the 16-year-olds without experience. When the intervention concluded, an increase in event rate was seen for the school license holders, but not for either group of 16-year-old drivers. There is strong evidence that giving young drivers video-based feedback, regardless of their age or level of driving experience, is effective in reducing the rate of safety-relevant events relative to a control group who do not receive feedback. Specific comparisons with regard to age and experience indicated that the age of the driver did not have an effect on the rate of safety-events, while experience did. Young drivers with six months or more of additional experience behind the wheel had nearly half as many safety-relevant events as those without that experience.

Elaboración de un video sobre calidad, seguridad y medio ambiente en la Unidad de Laboratorios Docentes (ULD) de la Facultad de Farmacia de la Universidad de Barcelona

La Unidad de Laboratorios Docentes (ULD) de la Facultad de Farmacia (UB) ha implantado un sistema de gestión de la calidad (SGC) que permite transmitir al estudiante una formación adicional con el objetivo de mejorar sus competencias transversales (siguiendo las directrices del Espacio Europeo de Educación Superior, EEES). Además, en el curso académico 06-07, se instauraron las Buenas Prácticas Ambientales (BPAL) para disponer de un sistema de gestión que incorporase los criterios de calidad, medioambiente y seguridad (sistema de gestión integrada, SGI). Durante el presente curso académico se ha procedido a la grabación y edición de un video sobre calidad, seguridad y medioambiente en la ULD con el objetivo de mejorar la formación transversal de los estudiantes facilitando la integración de los conocimientos y habilidades profesionales. De esta forma, al salir del entorno universitario, los licenciados y graduados de la Facultad de Farmacia dispondrán de un valor añadido en su formación, mejorando así sus competencias para el desarrollo de su futura profesión. En el video se muestra la manera de trabajar correctamente según las normas de calidad, seguridad y medioambiente recogidas además en un tríptico que se entrega a los estudiantes al acceder por primera vez a un laboratorio de prácticas. El video se difundirá a través de la página web de la ULD, de la videoteca de la UB, del canal You Tube Canal UB, así como de las asignaturas que lo soliciten (sirviendo de soporte para el personal docente).

Elaboración de un video sobre calidad, seguridad y medio ambiente en la Unidad de Laboratorios Docentes (ULD) de la Facultad de Farmacia de la Universidad de Barcelona

La Unidad de Laboratorios Docentes (ULD) de la Facultad de Farmacia (UB) ha implantado un sistema de gestión de la calidad (SGC) que permite transmitir al estudiante una formación adicional con el objetivo de mejorar sus competencias transversales (siguiendo las directrices del Espacio Europeo de Educación Superior, EEES). Además, en el curso académico 06-07, se instauraron las Buenas Prácticas Ambientales (BPAL) para disponer de un sistema de gestión que incorporase los criterios de calidad, medioambiente y seguridad (sistema de gestión integrada, SGI). Durante el presente curso académico se ha procedido a la grabación y edición de un video sobre calidad, seguridad y medioambiente en la ULD con el objetivo de mejorar la formación transversal de los estudiantes facilitando la integración de los conocimientos y habilidades profesionales. De esta forma, al salir del entorno universitario, los licenciados y graduados de la Facultad de Farmacia dispondrán de un valor añadido en su formación, mejorando así sus competencias para el desarrollo de su futura profesión. En el video se muestra la manera de trabajar correctamente según las normas de calidad, seguridad y medioambiente recogidas además en un tríptico que se entrega a los estudiantes al acceder por primera vez a un laboratorio de prácticas. El video se difundirá a través de la página web de la ULD, de la videoteca de la UB, del canal You Tube Canal UB, así como de las asignaturas que lo soliciten (sirviendo de soporte para el personal docente).

Mutual trust and cooperation in the evolutionary hawks-doves game

Using a new dynamical network model of society in which pairwise interactions are weighted according to mutual satisfaction, we show that cooperation is the norm in the hawks-doves game when individuals are allowed to break ties with undesirable neighbors and to make new acquaintances in their extended neighborhood. Moreover, cooperation is robust with respect to rather strong strategy perturbations. We also discuss the empirical structure of the emerging networks, and the reasons that allow cooperators to thrive in the population. Given the metaphorical importance of this game for social interaction, this is an encouraging positive result as standard theory for large mixing populations prescribes that a certain fraction of defectors must always exist at equilibrium.

Cardiovascular effects in patrol officers are associated with fine particulate matter from brake wear and engine emissions

Background: Exposure to fine particulate matter air pollutants (PM2.5) affects heart rate variability parameters, and levels of serum proteins associated with inflammation, hemostasis and thrombosis. This study investigated sources potentially responsible for cardiovascular and hematological effects in highway patrol troopers. Results: Nine healthy young non-smoking male troopers working from 3 PM to midnight were studied on four consecutive days during their shift and the following night. Sources of in-vehicle PM2.5 were identified with variance-maximizing rotational principal factor analysis of PM2.5-components and associated pollutants. Two source models were calculated. Sources of in-vehicle PM2.5 identified were 1) crustal material, 2) wear of steel automotive components, 3) gasoline combustion, 4) speed-changing traffic with engine emissions and brake wear. In one model, sources 1 and 2 collapsed to a single source. Source factors scores were compared to cardiac and blood parameters measured ten and fifteen hours, respectively, after each shift. The "speed-change" factor was significantly associated with mean heart cycle length (MCL, +7% per standard deviation increase in the factor score), heart rate variability (+16%), supraventricular ectopic beats (+39%), % neutrophils (+7%), % lymphocytes (-10%), red blood cell volume MCV (+1%), von Willebrand Factor (+9%), blood urea nitrogen (+7%), and protein C (-11%). The "crustal" factor (but not the "collapsed" source) was associated with MCL (+3%) and serum uric acid concentrations (+5%). Controlling for potential confounders had little influence on the effect estimates. Conclusion: PM2.5 originating from speed-changing traffic modulates the autonomic control of the heart rhythm, increases the frequency of premature supraventricular beats and elicits proinflammatory and pro-thrombotic responses in healthy young men. [Authors]

Observational methodology in football: Development of an instrument to study the offensiva game in football.

The following paper introduces a new approach to the analysis of offensive game in football. Therefore, the main aim of this study was to create an instrument for collecting information for the analysis of offensive action and interactions game. The observation instrument that was used to accomplish the main objective of this work consists of a combination of format fields (FC) and systems of categories (SC). This methodology is a particular strategy of the scientific method that has as an objective to analyse the perceptible behaviour that occurs in habitual contexts, allowing them to be formally recorded and quantified and using an ad hoc instrument in order to obtain a behaviour systematic registration that, since they have been transformed in quantitative data with the necessary reliability and validity determined level, will allow analysis of the relations between these behaviours. The codifications undertaken to date in various games of football have shown that it serves the purposes for which it was developed, allowing more research into the offensive game methods in football.