Evaluation of the changes in working limits in an automobile assembly line using simulation

The aim of the work presented in this paper consists of the development of a decision-making support system, based on discrete-event simulation models, of an automobile assembly line which was implemented within an Arena simulation environment and focused at a very specific class of production lines with a four closed-loop network configuration. This layout system reflects one of the most common configurations of automobile assembly and preassembly lines formed by conveyors. The sum of the number of pallets on the intermediate buffers, remains constant, except for the fourth closed-loop, which depends on the four-door car ratio (x) implemented between the door disassembly and assembly stations of the car body. Some governing equations of the four closed-loops are not compatible with the capacities of several intermediate buffers for certain values of variable x. This incompatibility shows how the assembly line cannot operate in practice for x0,97 in a stationary regime, due to the starvation phenomenon or the failure of supply to the machines on the production line. We have evaluated the impact of the pallet numbers circulating on the first closed-loop on the performance of the production line, translated into the number of cars produced/hour, in order to improve the availability of the entire manufacturing system for any value of x. Until the present date, these facts have not been presented in specialized literature. © 2012 American Institute of Physics

Cooperation in costly-access environments

Understanding cooperative behavior in biological and social systems constitutes a scientific challenge, being the object of intense research over the past decades. Many mechanisms have been proposed to explain the presence and persistence of cooperation in those systems, showing that there is no unique explanation, as different scenarios have different possible driving forces. In this paper, we propose a model to study situations in which voluntary participation involves an access cost to the cooperative interaction, besides the cost associated with cooperation. The proposed costly-access prisoner’s dilemma (PD), a symmetric donation game with voluntary and costly participation, breaks the symmetry between abstainers and participants of the voluntary PD. A mean-field approach shows that, in well-mixed populations, the dynamic always leads the system to abstention. However, depending on the return parameter, numerical simulations in structured populations display an alternating behavior between mono-strategic, multi-stable, and coexistence phases. This behavior is fully explained through a theoretical analysis of the strategic motifs, the transitions being determined by the change in stability of those motifs

Relación entre las pruebas de funcionalidad de la marcha en personas con daño cerebral adquirido en fase subaguda

Objetivo: Analizar el grado de relación entre cuatro pruebas que valoran la funcionalidad de la marcha en sujetos jóvenes con daño cerebral adquirido (DCA) en fase subaguda y conocer el grado de relación entre estas pruebas y la percepción subjetiva de seguridad en actividades de la vida diaria. Metodología: 67 participantes jóvenes con DCA en fase subaguda (43 hombres y 24 mujeres) con una edad media 35,09 años. Se realizó estadística descriptiva de todas las variables demográficas: género, edad, IMC, meses desde que se produjo la lesión y etiología lesional. Para analizar si existe correlación entre las variables se utilizó el coeficiente de Pearson. Resultados: El Timed 10-Meter Walk presenta una correlación muy alta con Timed Up and Go (TUG) (r=093), alta con el 6-Minute Walk Test (r=0,77) y moderada con el Step Test (r=0,56). El 6-Minute Walk Test presenta una correlación alta con el TUG (r=0,82) y una correlación moderada con el Step Test (r=0,69). El Step Test presenta una correlación moderada con el TUG (r= -0,68). The Activities-specific Balance Confidence Scale (ABC) presenta una correlación moderada con el Timed 10-Meter Walk (r=0,42), TUG (R=0,40), 6-Minute Walk Test (r=0,40) y Step Test (r=0,44). Conclusiones: Las pruebas de funcionalidad de la marcha presentan una correlación significativa entre moderada y muy alta en personas jóvenes con DCA. El ABC presenta una correlación significativa moderada con las cuatro variables de funcionalidad de la marcha analizadas en esta població

Relación de la mejora de la calidad de vida de los sujetos que practican actividad física con daño cerebral adquirido

RELACIÓN DE LA MEJORA DE LA CALIDAD DE VIDA DE LOS SUJETOS QUE PRACTICAN ACTIVIDAD FÍSICA CON DEÑO CEREBRAL ADQUIRID

Physical activity quantification in elder women

Cuantificación de la actividad física en mujeres mayores

Occupational Diseases and Perceived Health in Operating Room Nurses : A Multicenter Cross-Sectional Observational Study

Background: The surgical environment has multiple factors that could affect nurses' health. The aim was to determine the effects of the working environment of operating room nurses on their health compared to hospitalization nurses. Methods: A sample of operating room nurses and hospitalization nurses were included in the study and participated by filling in a self-report survey containing sociodemographic data items, the validated Nordic and SF12 scales and a list of medical conditions. Results: Three hundred and thirty-one nurses participated in the study. Statistically significant results had obtained for diagnoses of musculoskeletal disorders and contact dermatitis among the operating room nurses. Conclusion/Application to Practice: Continuous training in ergonomics is essential. Moreover, surgical protocols for preventing infection should be revised, optimizing the chlorhexidine content of soaps to reduce the risk of lesions among the surgical staff

Abiotrophia defectiva, una causa infrecuente de ictus cardioembólico

Abiotrophia defectiva supone una causa poco frecuente de endocarditis con una elevada tasa de embolización en comparación con otras endocarditis por estreptococo. Las complicaciones neurológicas pueden presentarse en el 20-40% de los casos, destacando aneurismas intracraneales y hemorragias subaracnoideas. Su aislamiento en el sistema nervioso central (SNC) es extremadamente raro y en la mayoría de los casos se asocia a procedimientos neuroquirúrgicos previos. Presentamos el caso de una paciente de 51 años que sufrió un ictus isquémico como complicación de una endocarditis por A. defectiva y se revisan los casos de infecciones del SNC causadas por dicho microorganismo. La relevancia del caso radica en su singularidad, debido a la ausencia de enfermedad valvular previa en la paciente y sin historia reciente de procedimientos invasivos o intervenciones quirúrgicas. Abiotrophia defectiva is a rare cause of endocarditis with a high embolization rate compared to other streptococcal endocarditis. Neurological complications may occur in 20-40% of cases, and include intracranial aneurysms and subarachnoid hemorrhage. Its isolation in the central nervous system (CNS) is extremely rare and is associated with previous neurosurgical procedures. We present the case of a 51-year-old patient who suffered an ischemic stroke as a complication of A. defectiva endocarditis, and the cases of CNS infections caused by this microorganism are reviewed. The relevance of the case lies in its singular character, due to the absence of previous valve disease in the patient without a recent history of invasive procedures or surgical interventions

Alternativas terapéuticas a la situación de «escalada simétrica» en terapia de familia.

Se realiza en este trabajo una revisión de los aspectos terapéuticos de la situación de Escalada simétrica en Terapia Familia

Alternativas terapéuticas a la situación de «escalada simétrica» en terapia de familia.

Se realiza en este trabajo una revisión de los aspectos terapéuticos de la situación de Escalada simétrica en Terapia Familia