Optimizing a Simple Natural Dye Production Method for Dye-Sensitized Solar Cells: Examples for Betalain (Bougainvillea and Beetroot Extracts) and Anthocyanin Dyes

We present a study about the sensitizers extracted from natural resources. This paper focuses on how to select, extract and characterize natural dyes, giving some guides to establish a protocol for the whole process of fabricating and using these dyes. The influence of the extraction solvent and method, and of parameters such as pH are analyzed. Also, dye precursor and dye extract stability have been studied, as well as how the dye adsorbs onto substrates and the effect of mixing or concentrating the extracts. Results concerning betalain pigments present in bougainvillea and beetroot extracts, and anthocyanins in eggplant extracts, analyzed by using UV-Vis spectrometry, are included. As an example of application, we report procedures intended to test and enhance the dye potential as a main component of dye-sensitized solar cells (DSSCs). DSSCs mimic nature’s photosynthesis and have some advantages like an easy and low-cost fabrication procedure. Their efficiency depends on its design and fabrication process and also on the different components involved. Hence, optimizing each component is essential to achieve the best performance, and thus the dye used as a sensitizer is crucial. We fabricate cells by using a simple procedure: As the interest is focused on the sensitizer, the same consecutive steps are followed, varying only the dye extract. Among all the natural-dyes tested, beetroot extract reaches up to 0.47% cell efficiency, which is near the highest values found in literature for this pigment

Quantification of Total Phenolic and Carotenoid Content in Blackberries (Rubus Fructicosus L.) Using Near Infrared Spectroscopy (NIRS) and Multivariate Analysis

A rapid method to quantify the total phenolic content (TPC) and total carotenoid content (TCC) in blackberries using near infrared spectroscopy (NIRS) was carried out aiming to provide reductions in analysis time and cost for the food industry. A total of 106 samples were analysed using the Folin-Ciocalteu method for TPC and a method based on Ultraviolet-Visible Spectrometer for TCC. The average contents found for TPC and TCC were 24.27 mg·g−1 dw and 8.30 µg·g−1 dw, respectively. Modified partial least squares (MPLS) regression was used for obtaining the calibration models of these compounds. The RPD (ratio of the standard deviation of the reference data to the standard error of prediction (SEP)) values from external validation for both TPC and TCC were between 1.5 < RPDp < 2.5 and RER values (ratio of the range in the reference data to SEP) were 5.92 for TPC and 8.63 for TCC. These values showed that both equations were suitable for screening purposes. MPLS loading plots showed a high contribution of sugars, chlorophyll, lipids and cellulose in the modelling of prediction equations

Benchmarking research performance at the University. Level with information theoretic measures

This paper presents a new method for comparing universities based on information theoretic measures. The research output of each academic institution is represented statistically by an impact-factor histogram. To this aim, for each academic institution we compute the probability of occurrence of a publication with impact factor in different intervals. Assuming the probabilities associated with a pair of academic institutions our objective is to measure the Information Gain between them. To do so, we develop an axiomatic characterization of relative information for predicting institution-institution dissimilarity. We use the Spanish university system as our scenario to test the proposed methodology for benchmarking three universities with the rest as a case study. For each case we use different scientific fields such as Information and Communication Technologies, Medicine & Pharmacy, and Economics & Business as we believe comparisons must take into account their disciplinary context. Finally we validate the Information Gain values obtained for each case with previous studies

The municipal solid waste in a municipality of central Mexico: analysis of factors that influence their management

Los residuos sólidos urbanos (RSU) son aquellos de características domiciliarias y son un gran reto para los gobiernos municipales en México. En este trabajo, a manera de ejemplo, se analiza el manejo de los RSU del municipio de Huitzilac (estado de Morelos), en el centro de México, como base para mejorar la eficiencia de su manejo. Se llevó a cabo un diagnóstico de la generación y manejo de los residuos, utilizando bibliografía disponible y realizando encuestas a los trabajadores involucrados en la recolección y transporte; a los del sector informal y a habitantes del municipio. Los resultados demuestran que la infraestructura del municipio y el personal contratado, son insuficientes, lo que provoca que los habitantes busquen alternativas para la disposición final de los mismos. Los RSU son depositados en un vertedero a cielo abierto, que no cumple con la legislación en la materia, donde se encuentran personas que recuperan residuos valorizables trabajando en condiciones que ponen en riesgo su salud. Aunque algunos habitantes separan sus residuos, la recolección y el transporte no son diferenciados. El barrido, la recolección y las condiciones del sitio de disposición final, deben ser mejorados, además de incluir el compromiso y la participación de la poblaciónOs resíduos sólidos urbanos (RSU) são aqueles de características domiciliares e são um grande desafio para os governos municipais do México. Neste trabalho, como exemplo, é analisada a gestão dos RSU no município de Huitzilac (Es - tado de Morelos), no interior do México, como base para melhoria da eficiência de sua ges - tão. Foi realizado um diagnóstico da geração e gestão dos resíduos, por meio de bibliografía disponível e pesquisa junto aos trabalhadores envolvidos na coleta e transporte; junto ao setor informal e habitantes do município. Os resulta -dos mostram que a infraestrutura do município, bem como o pessoal contratado, são insuficien - tes, o que faz com que os moradores busquem alternativas para a deposição final dos resíduos. Os RSU são depositados em aterros a céu aber - to em desconformidade com a legislação. Nes tes aterros verificam-se pessoas que trabalham recolhendo resíduos que podem ser valorados, colocando em risco sua saúde. Embora alguns habitantes separem seus resíduos, a coleta e o transporte não são diferenciados. A varredura, coleta e condições do local de disposição final devem ser aprimoradas, além de incluir o com - prometimento e a participação da população.The municipal solid waste (MSW) are those of domiciliary characteristics and are a great challenge for the municipal governments in Mexico. In this work, as an example, we analyze the management of MSW in the municipality of Huitzilac (Morelos State), in the center of Me - xico, as a basis to improve their management efficiency. A diagnosis of the waste generation and management was carried out, using biblio - graphy available and carrying out surveys to the collection and transport workers; to those of the informal sector and to municipality inha - bitants. The results show that the municipality infrastructure, as well as the personnel hired, is insufficient, which causes that the inhabitants look for alternatives for the MSW final dispo - sition. The MSW are deposited in an open-air dump, which does not comply with the environ - mental regulation. In this dump, people recover valuable to waste working in conditions that put their health at risk. Although some inhabitants separate their waste, collection and transport are not differentiated. The sweep, collection, and final disposal conditions must be impro - ved, in addition to including the commitment and participation of the populationIncluye referencias bibliográficas

Mapping citation patterns of book chapters in the Book Citation Index

Complementary Material to this study can be found at http://hdl.handle.net/10481/22587.In this paper we provide the reader with a visual representation of relationships among the impact of book chapters indexed in the Book Citation Index using information gain values and published by different academic publishers in specific disciplines. The impact of book chapters can be characterized statistically by citations histograms. For instance, we can compute the probability of occurrence of book chapters with a number of citations in different intervals for each academic publisher. We predict the similarity between two citation histograms based on the amount of relative information between such characterizations. We observe that the citation patterns of book chapters follow a Lotkaian distribution. This paper describes the structure of the Book Citation Index using ‘heliocentric clockwise maps’ which allow the reader not only to determine the grade of similarity of a given academic publisher indexed in the Book Citation Index with a specific discipline according to their citation distribution, but also to easily observe the general structure of a discipline, identifying the publishers with higher impact and output.This research was sponsored by the Spanish Board for Science and Technology (MICINN) under grant TIN2010- 15157 co financed with European FEDER funds

Mapping academic institutions according to their journal publication profile: Spanish universities as a case study

Post-print versionWe introduce a novel methodology for mapping academic institutions based on their journal publication profiles. We believe that journals in which researchers from academic institutions publish their works can be considered as useful identifiers for representing the relationships between these institutions and establishing comparisons. However, when academic journals are used for research output representation, distinctions must be introduced between them, based on their value as institution descriptors. This leads us to the use of journal weights attached to the institution identifiers. Since a journal in which researchers from a large proportion of institutions published their papers may be a bad indicator of similarity between two academic institutions, it seems reasonable to weight it in accordance with how frequently researchers from different institutions published their papers in this journal. Cluster analysis can then be applied to group the academic institutions, and dendrograms can be provided to illustrate groups of institutions following agglomerative hierarchical clustering. In order to test this methodology, we use a sample of Spanish universities as a case study. We first map the study sample according to an institution’s overall research output, then we use it for two scientific fields (Information and Communication Technologies, as well as Medicine and Pharmacology) as a means to demonstrate how our methodology can be applied, not only for analyzing institutions as a whole, but also in different disciplinary contexts

The selective reduction of NOx with propene on Pt-beta catalyst: a transient study

The mechanism of the NO/C3H6/O2 reaction has been studied on a Pt-beta catalyst using transient analysis techniques. This work has been designed to provide answers to the volcano-type activity behaviour of the catalytic system, for that reason, steady state transient switch (C3H6/NO/O2 → C3H6/Ar/O2, C3H6/Ar/O2 → C3H6/NO/O2, C3H6/NO/O2 → Ar/NO/O2, Ar/NO/O2 → C3H6/NO/O2, C3H6/NO/O2 → C3H6/NO/Ar and C3H6/NO/Ar → C3H6/NO/O2) and thermal programmed desorption (TPD) experiments were conducted below and above the temperature of the maximum activity (Tmax). Below Tmax, at 200 °C, a high proportion of adsorbed hydrocarbon exists on the catalyst surface. There exists a direct competition between NO and O2 for Pt free sites which is very much in favour of NO, and therefore, NO reduction selectively takes place over hydrocarbon combustion. NO and C3H6 are involved in the generation of partially oxidised hydrocarbon species. O2 is essential for the oxidation of these intermediates closing the catalytic cycle. NO2 is not observed in the gas phase. Above Tmax, at 230 °C, C3H6 ads coverage is negligible and the surface is mainly covered by Oads produced by the dissociative adsorption of O2. NO2 is observed in gas phase and carbon deposits are formed at the catalyst surface. From these results, the state of Pt-beta catalyst at Tmax is inferred. The reaction proceeds through the formation of partially oxidised active intermediates (CxHyOzNw) from C3H6 ads and NOads. The combustion of the intermediates with O2(g) frees the Pt active sites so the reaction can continue. Temperature has a positive effect on the surface reaction producing active intermediates. On the contrary, formation of NOads and C3H6 ads are not favoured by an increase in temperature. Temperature has also a positive effect on the dissociation of O2 to form Oads, consequently, the formation of NO2 is favoured by temperature through the oxygen dissociation. NO2 is very reactive and produces the propene combustion without NO reduction. These facts will determine the maximum concentration of active intermediates and consequently the maximum of activity.The authors thank the Spanish Ministry of Education and Science (project CTQ2005-01358) for the financial support

Eficiencia técnica de la atención al paciente con diabetes en el primer nivel = Technical efficiency in primary care for patients with diabetes

Resumen Objetivo. Cuantificar en un primer nivel la eficiencia técnica de la atención al paciente con diabetes y distinguir la provisión de servicios y los resultados en salud, además de reconocer las fuentes potenciales de variación. Material y métodos. Se incluyeron insumos, actividades clínicas y resultados en salud de 47 clínicas familiares del IMSS Nuevo León. La medida de la eficiencia se realizó mediante el análisis envolvente de datos y se aplicaron modelos de regresión de Tobit. Resultados. Siete clínicas fueron eficientes en cuanto a la provisión de servicios y nueve en salud; dos coincidieron en ambos aspectos. La localización metropolitana y el total de consultas favorecieron la eficiencia en relación con la provisión de servicios, cualesquiera que fueran los atributos del paciente; y la edad del médico, la eficiencia de los resultados en salud. Conclusiones. El desempeño varió en una misma unidad y entre una y otra; algunas fueron eficientes para suministrar servicios y otras para mejorar la salud. Las fuentes de variación también difirieron. Se recomienda incluir ambos productos en el estudio de la eficiencia en diabetes en el primer nivel. Abstract Objective. To quantify the technical efficiency of diabetes care in family practice settings, characterize the provision of services and health results, and recognize potential sources of variation. Material and Methods. We used data envelopment analysis with inputs and outputs for diabetes care from 47 family units within a social security agency in Nuevo Leon. Tobit regression models were also used. Results. Seven units were technically efficient in providing services and nine in achieving health goals. Only two achieved both outcomes. The metropolitan location and the total number of consultations favored efficiency in the provision of services regardless of patient attributes; and the age of the doctor, the efficiency of health results. Conclusions. Performance varied within and among family units; some were efficient at providing services while others at accomplishing health goals. Sources of variation also differed. It is necessary to include both outputs in the study of efficiency of diabetes care in family practice settings

COMPARATIVE STUDY BETWEEN THE THEORY OF PLANNED BEHAVIOUR AND THE VALUE-BELIEF-NORM MODEL REGARDING THE ENVIRONMENT, ON SPANISH HOUSEWIVES? RECYCLING BEHAVIOUR

Environmental behaviors have been analyzed from different theoretical models. The theory of planned behavior emphasizes the attitudinal aspects associated with behavior, while the value–belief–norm model regarding the environment focuses on the importance of moral components when setting environmental behaviors in motion. The objective of this study was to analyze both models, comparing both their degree of fit and their predictive power regarding recycling behavior. To do so, we used a sample made up of 154 Spanish housewives. The results indicated that despite the fact that the theory of planned behavior is a general model for predicting and explaining behavior, it has a greater degree of fit and greater capacity to predict recycling behavior than the value–belief–norm model regarding the environment

La utilización del concepto de pH en la publicidad y su relación con las ideas que manejan los alumnos : aplicaciones en el aula

The broadcast on TV of some commercials where the value of the pH in the advertised products was presented as beneficial, prompted us to study them to analyse the ideas related with the acids and bases that they have. Here, we also seek possible coincidences with the ideas that students sustain. We also present a sequence of classroom activities to use commercials to work the concepts of pH and neutralization therein involved