Diffusive Transport Enhanced by Thermal Velocity Fluctuations

We study the contribution of advection by thermal velocity fluctuations to the effective diffusion coefficient in a mixture of two indistinguishable fluids. The enhancement of the diffusive transport depends on the system size L and grows as \ln(L/L_0) in quasi two-dimensional systems, while in three dimensions it scales as L_0^{-1}-L^{-1}, where L_0 is a reference length. The predictions of a simple fluctuating hydrodynamics theory are compared to results from particle simulations and a finite-volume solver and excellent agreement is observed. Our results conclusively demonstrate that the nonlinear advective terms need to be retained in the equations of fluctuating hydrodynamics when modeling transport in small-scale finite systems.Comment: To appear in Phys. Rev. Lett., 201

idmTPreg: Regression Model for Progressive Illness Death Data

The progressive illness-death model is frequently used in medical applications. For example, the model may be used to describe the disease process in cancer studies. We have developed a new R package called idmTPreg to estimate regression coefficients in datasets that can be described by the progressive illness-death model. The motivation for the development of the package is a recent contribution that enables the estimation of possibly time-varying covariate effects on the transition probabilities for a progressive illness-death data. The main feature of the package is that it befits both non-Markov and Markov progressive illness-death data. The package implements the introduced estimators obtained using a direct binomial regression approach. Also, variance estimates and confidence bands are implemented in the package. This article presents guidelines for the use of the package.BERC 2014-2017 SEV-2013-0323 MTM2016-76969-P FP7/2011: Marie Curie Initial Training Network MEDIASRE

Motor differences in cadet taekwondo athletes according to competition level

El objetivo de este estudio es observar las diferencias entre atletas cadetes de Taekwondo de diferentes niveles competitivos en términos antropométricos, de potencia muscular, flexibilidad y velocidad de reacción. Veinte atletas varones fueron analizados, divididos en dos grupos: medallistas nacionales y no medallistas nacionales. Para cada atleta se tomaron datos antropométricos, de velocidad de reacción, potencia muscular y rango de movimiento articular de la articulación coxofemoral. Los atletas medallistas mostraron valores significativamente menores en altura, envergadura, tiempo de reacción óculo-podal, y tiempo de reacción óculo-manual con mano no dominante; y valores mayores para longitud de piernas, flexión pasiva de cadera, y abducción de cadera tanto activa como pasiva. Las leves diferencias observadas entre grupos en potencia muscular, grasa corporal y flexión activa de cadera no concuerdan con estudios previos. Conocer está información podría ser de interés para los entrenadores para llevar a cabo programas de detección de talentosThe aim of this study was to determine the differences between Taekwondo cadet athletes belonging to different competition levels in terms of anthropometry, legs power, flexibility and reaction time. Twenty male athletes were analysed, divided in two groups: national medallist and non-national medallist. Data of every athlete’s anthropometric measurements, reaction speed ability, leg power and hip ROM (range of movement) were taken. Medallist athletes showed significantly lower values for height, arm span, foot reaction time (dominant and non-dominant) and non-dominant hand reaction time; and higher values for leg length, passive hip flexion, active hip abduction and passive hip abduction in ROM tests. Slight differences observed between medallists and non-medallists in leg power (CMJ), body fat (Σ skinfolds) and active hip flexion do not agree with previous studies. Knowing this information could be interesting for coaches in order to carry out talent detection program

Multi-item Inventory Problem: Literature Review and a Proposal for Practitioners

[EN] Inventory managers have to assign an inventory policy to each item seeking to satisfy a required global service level with the lowest inventory cost. This paper reviews the existing literature and, based on current research, the most appropriate options are proposed to be used by practitioners.[ES] Los gestores de inventario tienen que asignar una política de inventario a cada artículo con el fin de satisfacer un nivel de servicio global requerido con el menor coste de inventario. En el presente documento se examina la bibliografía existente y, sobre la base de las investigaciones actuales, se proponen las opciones más apropiadas para su utilización práctica.Cardós, M.; De-La-Fuente-Aragón, M.; Ros-Mcdonnell, L. (2021). Multi-item Inventory Problem: Literature Review and a Proposal for Practitioners. Direccion y Organizacion. 74:67-80. https://doi.org/10.37610/dyo.v0i74.603S67807

Regeneración de un "aulagar" con Ulex europaeus después de un incendio en el norte de España

The recuperation of a shrubland characterized by the presence of Genista hispánica ssp. occidentalis, Ulex europaeus and Erica vagans after of a fire, near Oviedo (North Spain) is studied. The regeneration strategy of Erica vagans was by means of vegetative regrowth. The recolonization of Ulex europaeus and Genista hispánica ssp. occidentalis was both vegetative and from seed, although in the last species the establishment by seedlings was very infrequent. The post-fire vegetation development was affected by floristic composition of shrubland previous to the fire.[es] Se estudia la recuperación de un matorral caracterizado por la presencia de Genista hispánica ssp. occidentalis, Ulex europaeus y Erica vagans después de un incendio, en las proximidades de Oviedo. La estrategia regenerativa de Erica vagans es mediante rebrote vegetativo, mientras Ulex europaeus y Genista hispánica ssp. occidentalis tienen capacidad de regenerarse por rebrote vegetativo y por semilla, aunque en este último taxon, el mecanismo de regeneración a través de plántulas fue muy escaso. El desarrollo de la vegetación está muy marcado por la composición florística previa al fuego. [fr] On à étudié la récupération de broussailles caractérisées par la présence de Genista hispánica ssp. occidentalis, Ulex europaeus et Erica vagans, après un incendie prés d’Oviedo (Nord de Espagne). La stratégie de régénération d’Erica vagans se fait moyennant des pousses végétatives, tandis que la régénération d’Ulex europaeus et Genista hispánica ssp. occidentalis s'esf faite par pousses végétatives et par graines, bien que pour ce dernier taxon, le mécanisme de régénération au travers de plantules a été très rare. Le développement de la végétation est très marqué par la composition floristique existante durant l'incendie

A parallel computation approach for solving multistage stochastic network problems

This paper presents a parallel computation approach for the efficient solution of very large multistage linear and nonIinear network problems with random parameters. These problems resul t from particular instances of models for the robust optimization of network problems with uncertainty in the values of the right-hand side and the objective function coefficients. The methodology considered here models the uncertainty using scenarios to characterize the random parameters. A. scenario tree is generated and, through the use of full-recourse techniques, an implementable solution is obtained for each group of scenarios at each stage along the planning horizon. As a consequence of the size of the resulting problems, and the special structure of their constraints, these models are particularly well-suited for the application of decomposition techniques, and the solution of the corresponding subproblems in a parallel computation environment. An Augmented Lagrangian decomposition algorithm has been implemented on a distributed computation environment, and a static load balancing approach has been chosen for the parallelization scheme. given the subproblem structure of the model. Large problems -9000 scenarios and 14 stages with a deterministic equivalent nonlinear model having 166000 constraints and 230000 variables- are solved in 15 minutes on a cluster of 4 small (16 Mflops) workstations. An extensive set of computational experiments is reported; the numerical results and running times obtained for our test set, composed of large-scale real-life problems, confirm the efficiency of this procedure

Prevalence, Related Factors, and Levels of Burnout Syndrome Among Nurses Working in Gynecology and Obstetrics Services: A Systematic Review and Meta-Analysis

Background: Although burnout levels and the corresponding risk factors have been studied in many nursing services, to date no meta-analytical studies have been undertaken of obstetrics and gynecology units to examine the heterogeneity of burnout in this environment and the variables associated with it. In the present paper, we aim to determine the prevalence, levels, and related factors of burnout syndrome among nurses working in gynecology and obstetrics services. Methods: A systematic review and meta-analysis of the literature were carried out using the following sources: CINAHL (Cumulative Index of Nursing and Allied Health Literature), LILACS (Latin American and Caribbean Health Sciences Literature), Medline, ProQuest (Proquest Health and Medical Complete), SciELO (Scientific Electronic Library Online), and Scopus. Results: Fourteen relevant studies were identified, including, for this meta-analysis, n = 464 nurses. The following prevalence values were obtained: emotional exhaustion 29% (95% CI: 11–52%), depersonalization 19% (95% CI: 6–38%), and low personal accomplishment 44% (95% CI: 18–71%). The burnout variables considered were sociodemographic (age, marital status, number of children, gender), work-related (duration of the workday, nurse-patient ratio, experience or number of miscarriages/abortions), and psychological (anxiety, stress, and verbal violence). Conclusion: Nurses working in obstetrics and gynecology units present high levels of burnout syndrome. In over 33% of the study sample, at least two of the burnout dimensions considered are apparent.This research was funded by the Excellence Research Project (P11HUM-7771) provided by the Andalusian Government (Spain)