Chloride Penetration Prediction in Concrete through an Empirical Model Based on Constant Flux Diffusion

An empirical model based on constant flux is presented for chloride transport through concrete in atmospherical exposure conditions. A continuous supply of chlorides is assumed as a constant mass flux at the exposed concrete surface. The model is applied to experimental chloride profiles obtained from a real marine structure, and results are compared with the classical error-function model. The proposed model shows some advantages. It yields a better predictive capacity than the classical error-function model. The previously observed chloride surface concentration increases are compatible with the proposed model. Nevertheless, the predictive capacity of the model can fail if the concrete microstructure changes with time. The model seems to be appropriate for well-maturated concretes exposed to a marine environment in atmospherical conditions.

Understanding the structure of the first atomic contact in gold

We have studied experimentally jump-to-contact (JC) and jump-out-of-contact (JOC) phenomena in gold electrodes. JC can be observed at first contact when two metals approach each other, while JOC occurs in the last contact before breaking. When the indentation depth between the electrodes is limited to a certain value of conductance, a highly reproducible behaviour in the evolution of the conductance can be obtained for hundreds of cycles of formation and rupture. Molecular dynamics simulations of this process show how the two metallic electrodes are shaped into tips of a well-defined crystallographic structure formed through a mechanical annealing mechanism. We report a detailed analysis of the atomic configurations obtained before contact and rupture of these stable structures and obtained their conductance using first-principles quantum transport calculations. These results help us understand the values of conductance obtained experimentally in the JC and JOC phenomena and improve our understanding of atomic-sized contacts and the evolution of their structural characteristics.

Validation of the Spanish version of mackey childbirth satisfaction rating scale

Background: The “Mackey Childbirth Satisfaction Rating Scale” (MCSRS) is a complete non-validated scale which includes the most important factors associated with maternal satisfaction. Our primary purpose was to describe the internal structure of the scale and validate the reliability and validity of concept of its Spanish version MCSRS-E. Methods: The MCSRS was translated into Spanish, back-translated and adapted to the Spanish population. It was then administered following a pilot test with women who met the study participant requirements. The scale structure was obtained by performing an exploratory factorial analysis using a sample of 304 women. The structures obtained were tested by conducting a confirmatory factorial analysis using a sample of 159 women. To test the validity of concept, the structure factors were correlated with expectations prior to childbirth experiences. McDonald’s omegas were calculated for each model to establish the reliability of each factor. The study was carried out at four University Hospitals; Alicante, Elche, Torrevieja and Vinalopo Salud of Elche. The inclusion criteria were women aged 18–45 years old who had just delivered a singleton live baby at 38–42 weeks through vaginal delivery. Women who had difficulty speaking and understanding Spanish were excluded. Results: The process generated 5 different possible internal structures in a nested model more consistent with the theory than other internal structures of the MCSRS applied hitherto. All of them had good levels of validation and reliability. Conclusions: This nested model to explain internal structure of MCSRS-E can accommodate different clinical practice scenarios better than the other structures applied to date, and it is a flexible tool which can be used to identify the aspects that should be changed to improve maternal satisfaction and hence maternal health.

Evolution of conducting channels in metallic atomic contacts under elastic deformation

We investigate both experimentally and theoretically the evolution of conductance in metallic one-atom contacts under elastic deformation. While simple metals like Au exhibit almost constant conductance plateaus, Al and Pb show inclined plateaus with positive and negative slopes. It is shown how these behaviors can be understood in terms of the orbital structure of the atoms forming the contact. This analysis provides further insight into the issue of conductance quantization in metallic contacts revealing important aspects of their atomic and electronic structures.

Psychometric behaviour of the strengths and difficulties questionnaire (SDQ) in the Spanish national health survey 2006

Background: The Strengths and Difficulties Questionnaire (SDQ) is a tool to measure the risk for mental disorders in children. The aim of this study is to describe the diagnostic efficiency and internal structure of the SDQ in the sample of children studied in the Spanish National Health Survey 2006. Methods: A representative sample of 6,773 children aged 4 to 15 years was studied. The data were obtained using the Minors Questionnaire in the Spanish National Health Survey 2006. The ROC curve was constructed and calculations made of the area under the curve, sensitivity, specificity and the Youden J indices. The factorial structure was studied using models of exploratory factorial analysis (EFA) and confirmatory factorial analysis (CFA). Results: The prevalence of behavioural disorders varied between 0.47% and 1.18% according to the requisites of the diagnostic definition. The area under the ROC curve varied from 0.84 to 0.91 according to the diagnosis. Factor models were cross-validated by means of two different random subsamples for EFA and CFA. An EFA suggested a three correlated factor model. CFA confirmed this model. A five-factor model according to EFA and the theoretical five-factor model described in the bibliography were also confirmed. The reliabilities of the factors of the different models were acceptable (>0.70, except for one factor with reliability 0.62). Conclusions: The diagnostic behaviour of the SDQ in the Spanish population is within the working limits described in other countries. According to the results obtained in this study, the diagnostic efficiency of the questionnaire is adequate to identify probable cases of psychiatric disorders in low prevalence populations. Regarding the factorial structure we found that both the five and the three factor models fit the data with acceptable goodness of fit indexes, the latter including an externalization and internalization dimension and perhaps a meaningful positive social dimension. Accordingly, we recommend studying whether these differences depend on sociocultural factors or are, in fact, due to methodological questions.

Percepción, activos intangibles y stakeholders: modelo para el análisis de imagen corporativa

El presente artículo abordará aproximaciones para la gestión de la imagen corporativa; pensada como un activo intangible que proyecta la institución. Además, se consideran diversos modelos y conceptos de capital intelectual que identifican factores relevantes hacia la toma decisión por parte de stakeholders. La percepción de imagen es un tema que ha suscitado interés por parte de instituciones, pues ésta se encuentra estrechamente vinculada a la formación integral de una idea que influye en el desarrollo de una actitud favorable o no hacia la reputación corporativa. De esta manera, los clientes, consumidores, proveedores, colaboradores, entre otros; reciben a través de distintas formas elementos que le ayudan a conformar una idea sobre la institución mediante sus percepciones; por lo que, orientar los esfuerzos y acciones en torno a este intangible, dará como resultado una rentabilidad no sólo monetaria sino una fidelidad y confianza por parte de sus stakeholders. Es así, que se ha visto la necesidad de proponer un modelo para el análisis de la imagen corporativa de instituciones, el mismo que consta de cinco categorías las cuales poseen parámetros de puntuación, construidos a partir de los aportes de diferentes autores.

Social Services in Times of Economic and Social Crisis: The case of Spain

The financial and economic crisis which originated in 2008 has had a severe impact on the population of the Southern European countries. The economic policies of austerity and public deficit control, as well as the neo-liberal and conservative social policies are redefining the public social protection systems, in particular the Social Services. In order to get to understand the current situation, we shall explain how the Social Services were developed in Spain and analyse the causes and consequences of the economic crisis. The working hypothesis is that the greater the increase on the population’s needs, the more developed the Social Services should be. We carried out a descriptive analysis of the situation as far as the social impacts of the crisis per region are concerned. We tested the hypothesis through a parametric model of analysis of variance (one-way ANOVA) triangulating with the non-parametric Kruscal-Wallis test. The working hypothesis failed. The regions with better developed Social Services show a lower level of poverty and social exclusion. The challenges that the public Social Services system faces in times of crisis is three-fold: 1) re-modelling of local administration and transferring of the municipal Social Services responsibilities to the regional administration; 2) an increase of the population at risk of poverty and social exclusion 3) impact on social policies.