Suchergebnisse

AbstractWe investigate the joint signature of coherent systems, under the assumption that the components have independent and identically distributed lifetimes. The joint signature, for a particular ordering of failure times, is an ‐dimensional matrix depending solely on the composition of the systems and independent of the underlying distribution function of the component lifetimes. The elements of the ‐dimensional matrix are formulated based on the joint signatures of numerous series of parallel systems. The number of the joint signatures involved is an exponential function of the number of the minimal cut sets of each original system and may, therefore, be significantly large. We prove that although this number is typically large, a great number of the joint signatures are repeated, or removed by negative signs. We determine the maximum number of different joint signatures based on the number of systems and components. It is independent of the number of the minimal cut sets of each system and is polynomial in the number of components. Moreover, we consider all permutations of failure times and demonstrate that the results for one permutation can be of use for the others. Our theorems are applied to various examples. The main conclusion is that the joint signature can be computed much faster than expected.

Objetivo: Las audiencias locales que se sitúan fuera de las capitales y de las grandes urbes deben conformarse con la información y contenidos televisivos nacionales, perdiendo la conexión con sus territorios debido al marcado centralismo de los medios capitalinos. Este artículo caracteriza las tensiones de las audiencias locales del norte de Chile en relación con su televisión local, también denominada de proximidad. Materiales y métodos: La metodología es cualitativa, realizándose grupos focales con las audiencias de seis comunas de la región de Coquimbo que tuviesen televisoras locales operativas y que declarasen ver periódicamente medios locales. Resultados: Entre los hallazgos se destaca el interés y el requerimiento de la ciudadanía por las noticias locales en un claro sentido de proximidad y cercanía con su territorio, detectando además otras demandas sociales, políticas, culturales y educativas de las audiencias que podrían ser canalizadas por las televisoras locales. Se evidencia un distanciamiento y crítica hacia contenidos sensacionalistas de la televisión nacional, siendo el centralismo informativo una de las razones para la poca empatía hacia estos medios de comunicación. A juicio de los participantes, las tensiones entre lo local y lo capitalino no solo se aprecian a nivel país, sino también entre capitales regionales, provincias y comunas, siguiendo la división político-administrativa de Chile. Conclusiones: Se concluye que existe una marcada preferencia por el contenido de proximidad, lo que se explica en parte por el alejamiento y crítica que se declara hacia los medios de cobertura nacional. Se plantean como tensiones la falta de espacios de comunicación y promoción del diálogo social que les permita a las audiencias ser escuchadas por sus actores políticos locales y regionales, desaprovechando el interés de la televidencia local por contenidos de proximidad que les permitan crecer, desarrollarse y lograr una mayor participación ciudadana en el ecosistema medial chileno.

Willis, EM orcid:0000-0001-7576-971X ; © 2020 The Author(s). Background: High rates of mental distress, mental illness, and the associated physical effects of psychological injury experienced by ambulance personnel has been widely reported in quantitative research. However, there is limited understanding of how the nature of ambulance work contributes to this problem, the significant large toll that emergency medical response takes on the individual, and particularly about late and cumulative development of work-related distress among this first responder workforce. Methods: This study examined peer-reviewed qualitative research published from 2 to 2018 to outline the effect of emergency medical response work on the psychological, psychosocial, and physical health of paramedics, ambulance officers, ambulance volunteers, and call-takers. Databases searched included: Ovid Medline, CINAHL, Ovid EMcare, PsychInfo and Scopus. The systematic review was organised around five key areas: Impact of the work on psychological wellbeing; impact of psychological stress on physical wellbeing; how work-related well-being needs were articulated; effects of workflow and the nature of the work on well-being; and, effects of organisational structures on psychological and physical well-being. Results: Thirty-nine articles met the eligibility criteria. Several factors present in the day-to-day work of ambulance personnel, and in how organisational management acknowledge and respond, were identified as being significant and contributing to mental health and well-being, or increasing the risk for developing conditions such as PTSD, depression, and anxiety. Ambulance personnel articulated their well-being needs across four key areas: Organisational support; informal support; use of humour; and individual mechanisms to cope such as detachment and external supports. Conclusions: Interactions between critical incidents and workplace culture and demands have an overwhelming impact on the psychological, physical and social well-being of ambulance personnel. These include day-to-day managerial actions and responses, the impact of shift work, poorly-managed rosters, and long hours of work with little time between for recovery. Mental health issues result from exposure to traumatic events, and the way managers and peers respond to worker distress. Ambulance personnel suffering from work-related stress feel abandoned by peers, management, and the service, during illness, in return-to-work, and post-retirement. Policy, programmes and interventions, and education need to occur at an individual, peer, organisational, and government level.