Minimal repair of failed components in coherent systems

© 2019 This document is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/ This document is the accepted version of a published work that appeared in final form in European Journal of Operational ResearchThe minimal repair replacement is a reasonable assumption in many practical systems. Under this as- sumption a failed component is replaced by another one whose reliability is the same as that of the component just before the failure, i.e., a used component with the same age. In this paper we study the minimal repair in coherent systems. We consider both the cases of independent and dependent compo- nents. Three replacement policies are studied. In the first one, the first failed component in the system is minimally repaired while, in the second one, we repair the component which causes the system fail- ure. A new technique based on the relevation transform is used to compute the reliability of the systems obtained under these replacement policies. In the third case, we consider the replacement policy which assigns the minimal repair to a fixed component in the system. We compare these three options un- der different stochastic criteria and for different system structures. In particular, we provide the optimal strategies for all the coherent systems with 1–4 independent and identically distributed components

The Dunkl–Williams constant, convexity, smoothness and normal structure

AbstractIn this paper we exhibit some connections between the Dunkl–Williams constant and some other well-known constants and notions. We establish bounds for the Dunkl–Williams constant that explain and quantify a characterization of uniformly nonsquare Banach spaces in terms of the Dunkl–Williams constant given by M. Baronti and P.L. Papini. We also study the relationship between Dunkl–Williams constant, the fixed point property for nonexpansive mappings and normal structure

Minimal repair of failed components in coherent systems

The minimal repair replacement is a reasonable assumption in many practical systems. Under this assumption a failed component is replaced by another one whose reliability is the same as that of the component just before the failure, i.e., a used component with the same age. In this paper we study the minimal repair in coherent systems. We consider both the cases of independent and dependent components. Three replacement policies are studied. In the first one, the first failed component in the system is minimally repaired while, in the second one, we repair the component which causes the system failure. A new technique based on the relevation transform is used to compute the reliability of the systems obtained under these replacement policies. In the third case, we consider the replacement policy which assigns the minimal repair to a fixed component in the system. We compare these three options under different stochastic criteria and for different system structures. In particular, we provide the optimal strategy for all the coherent systems with 1-4 independent and identically distributed components

Condiciones optimas de manipulación para la cuantificación de fibronectina en saliva

Introducción: La fibronectina (Fn) es una glucoproteína presente en múltiples fluidos y tejidos orgánicos, tanto en condiciones fisiológicas como patológicas. También en la saliva puede detectarse aunque en muy pequeñas cantidades y frecuentemente en cadenas fragmentadas, induce agregación bacteriana y sus niveles se reducen cuando aumentan los niveles de bacterias cariogénicas o periodontopatógenas. La capacidad infectiva de la saliva de los pacientes infectados por el virus de la inmunodificiencia humana (VIH) se ha relacionado con los niveles de esta proteína. En algunas enfermedades crónicas de la mucosa oral como es el liquen plano, la concentración de Fn salivar se encuentra reducida. También su cuantificación varía en presencia de algunos tumores como el carcinoma oral de células escamosas, aunque no puede considerarse un factor específico. Objetivo: Debido a la baja concentración de Fn en la saliva y a su labilidad en la forma soluble, las condiciones de recogida y conservación de las muestras son extremadamente importantes, por ello nos proponemos en el presente trabajo estandarizar dichas condiciones con el fin de poder cuantificarla de manera óptima. Material y método: Se determinó la concentración de Fn en saliva humana de 20 personas sanas de edades comprendidas entre 28 y 54 años mediante técnica de ELISA, comparando la concentración de la proteína en muestras frescas, conservadas 24 h a 4ºC, o congeladas a - 40ºC durante diferentes periodos de tiempo. Resultados y conclusiones: Tras comparar diferentes formas de conservación de las muestras de saliva, observamos que las condiciones óptimas son: recoger las muestras en tubos de vidrio, cuantificarlas inmediatamente tras su recogida o como máximo 24 horas después, conservándolas a 4ºC. La congelación y posterior descongelación para su cuantificación induce pérdidas de hasta el 60 % de la proteína.Introduction: Fibronectin (Fn) is a glycoprotein that is present in many body fluids and tissues in both physiological and pathological conditions. It can also be detected in the saliva, although only in very small quantities and frequently in broken chains. It induces bacterial aggregation and its levels fall when those of cariogenic or periodontal pathogenic bacteria rise. The infective capacity of the saliva of patients infected by human immunodeficiency virus (HIV) has been linked to the levels of this protein. In some chronic conditions of the oral mucosa, such as oral lichen planus, the concentration of salivary fibronectin is lower than usual. Fibronectin quantity also varies in the presence of some tumours, such as oral squamous cell carcinoma, although it cannot be considered a specific factor. Aims: Due to the low Fn concentration in saliva and its lability in the soluble form, sample collection and conservation conditions are extremely important. The aim of this study is therefore to standardise these conditions so that the Fn can be quantified in an optimum manner. Materials and methods: The Fn concentration in human saliva was determined in 20 healthy subjects aged between 28 and 54 by means of the ELISA technique and the concentration of the protein in fresh samples kept at 4ºC for 24 hours was compared with that of frozen samples kept at '40ºC for different periods of time. Results and Conclusions: After comparing different ways of conserving the saliva samples, we found that the optimum conditions were to collect the samples in glass tubes and to quantify them immediately after collection or conserve them at 4ºC and quantify them within a maximum of 24 hours. Freezing and later thawing for quantification induced losses of up to 60% of the protein

The Effect of Social Trust on Citizens’ Health Risk Perception in the Context of a Petrochemical Industrial Complex

Perceived risk of environmental threats often translates into psychological stress with a wide range of effects on health and well-being. Petrochemical industrial complexes constitute one of the sites that can cause considerable pollution and health problems. The uncertainty around emissions results in a perception of risk for citizens residing in neighboring areas, which translates into anxiety and physiological stress. In this context, social trust is a key factor in managing the perceived risk. In the case of industrial risks, it is essential to distinguish between trust in the companies that make up the industry, and trust in public institutions. In the context of a petrochemical industrial complex located in the port of Castellón (Spain), this paper primarily discusses how trust—both in the companies located in the petrochemical complex and in the public institutions—affects citizens’ health risk perception. The research findings confirm that while the trust in companies negatively affects citizens’ health risk perception, trust in public institutions does not exert a direct and significant effect. Analysis also revealed that trust in public institutions and health risk perception are essentially linked indirectly (through trust in companies)

Residents´ behaviour as a function of cognitive appraisals and affective responses toward a petrochemical industrial complex

Environmental degradation due to polluting industrial complexes constitutes a relevant issue for local community. Most studies focus on the negative externalities, in terms of pollution, of these industrial complexes, although some research has also explored the economic benefits of these installations and the harm their closure can inflict on the local economy. In the context of a petrochemical complex located in Castellón (Spain), the present paper analyses how residents' cognitive appraisal of the economic and environmental aspects leads to their affective responses, and how both elements – cognitive and affective – jointly explain their behavioural intention. The proposed hypotheses are tested on a sample of 992 individuals. The results confirm that cognitive appraisals, directly and by means of the affective response, have a significant influence on the residents' behavioural intention towards their place of residence. The findings also show that affective response has a higher impact than cognitive response and, additionally, that environmental aspects play a more important role than economic ones. Furthermore, the relationship between affects and behavioural intention has a greater weight among citizens who live closest to the petrochemical complex. Implications for firms' and public authorities' environmental management are discussed

Influencia de los estilos educativos paternos en el consumo de drogas en adolescentes

El presente estudio pretende examinar el papel predictivo de la percepcion de la educacion paterna por parte de los hijos, en el consumo de diferentes sustancias (alcohol, cannabis y tabaco) durante la adolescencia.Método: Se administro un cuestionario anonimo desarrollado para medir la cantidad de sustancias consumidas en una semana y el tipo de educacion percibida de sus padres, asi como diferentes variables personales. La muestra estaba compuesta por 1378 sujetos, con edades comprendidas entre los 13 y los 19 anos. El analisis se realizo a traves del Modelo de Regresion de Poisson.Resultados: El tipo de educacion recibida parece influir en funcion de la sustancia analizada. Se ha encontrado que un estilo educativo democratico autoritario es protector para el consumo de drogas y un estilo permisivo correlaciona con un mayor consumo. Por otro lado, la figura paterna influye en el consumo de alcohol y la de ambos padres en el consumo de cannabis y tabaco.Discusión: El tipo de educacion que reciben los adolescentes determina la utilizacion y el consumo que hacen de las drogas. Por tanto, es importante intervenir en el ambito familiar a traves de los programas de prevencion, ensenando a los padres las pautas mas adecuadas en la educacion de sus hijos

Noves dades sobre fongs ibèrics

Noves dades sobre fongs. Es presenten cinc espècies de fongs interessants per la seva raresa: Craterellus konradii Bourdot et Maire, Lepiota fuscovinacea F. H. Möller et J. E. Lange, Lepiota hystrix Möller et J. E. Lange, Lyophyllum fumosum (Pers.) P. D. Orton i L. rhopalopodium Clémençon, trobades a Barcelona, Girona i Cuenca (Espanya). Els diferents tàxons tractats van acompanyats de descripcions i iconografia original, així com de comentaris taxonòmics.New records of Iberian fungi. Five interesting rare species of fungi are reported: Cra terellus konradii Bourdot et Maire, Lepiota fuscovinacea F.H. Móller et J.E. Lange, Lepiota hystrix Möller et J.E. Lange, Lyophyllum fumosum (Pers.) P.D. Orton and L. rhopalopodium Clemençon, collected in Barcelona, Cuenca and Giron a (Spain). Descriptions, original iconography and comments are provided