A comparison of B16 melanoma cells and 3T3 fibroblasts concerning cell viability and ROS production in the presence of melatonin, tested over a wide range of concentrations

Melatonin is a pleiotropic molecule with many cellular and systemic actions, including chronobiotic effects. Beneficial effects are widely documented concerning the treatment of neoplastic diseases in vivo as well as reductions in viability of cultured cells from melanoma, one of the most aggressive cancers in humans. However, studies of its effects on non-tumor cells in vitro have not focused on viability, except for experiments aiming to protect against oxidotoxicity or other toxicological insults. Furthermore, there is no agreement on the range of effective melatonin concentrations in vitro, and the mechanisms that reduce cell viability have remained unclear. Tumor cell-specific increases in the production of reactive oxygen and nitrogen species (ROS/RNS) may provide a possible explanation. Our aim was to analyze the potential inhibition of tumor (B16 melanoma 4A5) and non-tumor cell (3T3 Swiss albino) viability using a wide range of melatonin concentrations (10-11-10-2 M), and to determine whether intracellular ROS enhancement was involved in this process. In the absence of fetal bovine serum (FBS), low melatonin concentrations (10-9-10-5 M) reduced the proliferation of melanoma cells with no effect in fibroblasts, whereas, in the presence of FBS, they had no effect or even increased the proliferation of both fibroblast and melanoma cells. Melatonin concentrations in the upper millimolar range increased ROS levels and reduced the viability of both cell types, but more markedly so in non-tumor cells. Thus, low melatonin concentrations reduce proliferation in this specific melanoma cell line, whereas high concentrations affect the viability of both tumor (B16 4A5 melanoma) and non-tumor (3T3 fibroblasts) cells. Increased ROS levels in both lines indicate a role for ROS production in the reduction of cell viability at high-but not low-melatonin concentrations, although the mechanism of action still remains to be elucidated. © 2013 by the authors; licensee MDPI, Basel, Switzerland.This project was funded by the Instituto de Salud Carlos III (RETICEF, RD06/0013/0019; RD06/0013/0001 and RD12/0043/0011), the Ministry of Education and Science (BFU2010-21945-C02-01) and a Research fellowship granted to MA Bonmatí (AP2009-1051).Peer Reviewe

New space vector modulation algorithms applied to multilevel converters with balanced DC-link voltage

This work presents a survey of new space vector modulation algorithms for high power voltage source multilevel converters. These techniques provide the nearest switching vectors sequence to the reference vector and calculates the on-state durations of the respective switching state vectors without involving trigonometric functions, look-up tables or coordinate system transformations which increase the computational load corresponding to the modulation of a multilevel converter. These algorithms drastically reduce the computational load maintained permitting the on-line computation of the switching sequence and the on-state durations of the respective switching state vectors. The on-state durations are reduced to a simple addition. In addition, the low computational cost of the proposed methods is always the same and it is independent of the number of levels of the converter. The algorithms have been satisfactorily implemented in very low-cost microcontrollers.Ministerio de Ciencia y Tecnología DPI 2001-308

Het zorgpotentieel in de netwerken van ouderen

Tamarix hohenackeri Bunge is reported here for the first time for the flora of Mexico. It also represents the first record for the American continent. This species, native from Asia, was collected along riversides of the river San Salvador (Ensenada, Baja California). A detailed morphological description of the newly reported taxon is provided, and the taxonomic treatment of T. hohenackeri is also discussed. As a result of this study, the presence of six species of the genus Tamarix is confirmed for Mexico, and a dichotomous key for the Tamarix species in Mexico is presented.Se documenta por primera vez la presencia de Tamarix hohenackeri Bunge para la flora de México. Se trata, a su vez, de la primera cita para el continente americano. Esta especie, nativa de Asia, ha sido recolectada en los márgenes del río San Salvador (Ensenada, Baja California). Se aporta una descripción morfológica detallada del nuevo taxon citado y se discute, también, su estatus taxonómico. Como resultado del estudio, se indica la presencia de seis especies del género Tamarix y además se aporta una clave para la identificación de los representantes de Tamarix en México

Is Sexual Attraction Independent of the Instrumental and Expressive Traits?

Sexual attraction is an essential part of sex, just as the instrumental and expressive traits are the mainstay of gender. Various hypotheses concerning the dimensionality and independence versus dependence/overlapping of these core entities were tested. A group of 423 university students completed the Sexual Attraction Questionnaire (SAQ; Fernández, Quiroga, & Rodríguez, 2006) and the 12-item Bem Sex Role Inventory (BSRI; Bem, 1974). Internal consistency and factor analyses (PAF) were conducted. The results support the dimensionality established for the SAQ and reveal some psychometric and conceptual weaknesses of the 12-item BSRI. The results also support the independence of the two cores: sexual attraction and the instrumental and expressive traits. The logical implications for the different viewpoints of the relations between sex and gender are discussed.Uno de los núcleos básicos de la realidad del sexo es la atracción sexual, al igual que uno de los núcleos básicos de género hace referencia a los dominios instrumental y expresivo. En este trabajo se van a poner a prueba las distintas hipótesis sobre la dimensionalidad de la atracción sexual y de los dominios instrumental y expresivo, a la par que la hipótesis de la independencia frente a la dependencia o solapamiento de ambas realidades. Se contó para ello con la participación de 423 estudiantes universitarios. Los instrumentos utilizados fueron el Cuestionario de Atracción Sexual (CAS; Fernández, Quiroga, & Rodríguez, 2006) y la versión de 12 ítems del Bem Sex Role Inventory (BSRI; Bem, 1974). Los resultados proporcionaron un claro apoyo empírico a la dimensionalidad establecida para el SAQ, a la par que dejaron al descubierto ciertas debilidades conceptuales y psicométricas del BSRI. Los resultados apoyan la independencia de los dos núcleos: la atracción sexual y los dominios instrumental y expresivo. Se establecen las implicaciones lógicas para las distintas posturas en torno a las relaciones del sexo y el género

Taxonomic identity of psammophytic populations of Teucrium from the inland sand dunes of Alicante province

La reciente revisión del género Teucrium para Flora Iberica señala su gran variabilidad, e incluso algunos tratamientos taxonómicos realizados para determinadas poblaciones geográficas pueden suscitar cierta controversia. Este es el caso de encuadrar en el seno del taxon Teucrium lusitanicum, algunas poblaciones sabulícolas del interior de la provincia de Alicante, que tradicionalmente han sido incluidas bajo la denominación de Teucrium dunense. En este trabajo, se han estudiado individuos de los dos táxones antes mencionados de diferentes localidades españolas, con el fin de comprobar su caracterización morfológica y determinar la identidad taxonómica de las poblaciones de Teucrium de los arenales del interior de la provincia de Alicante. Se ha realizado una revisión morfológica de diversos caracteres vegetativos y florales. Los resultados señalan que los individuos de Teucrium de dunas continentales alicantinas se aproximan morfológicamente al taxón T. dunense, atendiendo al tamaño y morfología de las hojas, color y grosor de los tricomas, y el diámetro de los glomérulos florales. Los análisis multivariables realizados (PCA y dendrograma) apoyan los resultados obtenidos.The recent taxonomical treatment of Teucrium for Flora Iberica outlined this remarkable variation and, therefore, certain taxonomic treatments could be considered controversial for some geographical populations. This is the case of the taxonomical identity of various inland sand dune populations of province of Alicante, which has been newly recognized as T. lusitanicum instead of their habitual denomination as T. dunense. In the present study, a morphological comparison among individuals of the two mentioned taxa from different Spanish localities has been done to check their morphological features and to infer the taxonomical identity of the samples from inland sand dunes of Alicante province. A morphological review based on both vegetative and floral characters is done. According to the results, the individuals from the inland sand dunes of Alicante are rather similarly to T. dunense, based on the size and shape of the leaves, the colour and width of the trichomes, and the width of the floral glomerule. Statistical analyses (PCA and dendrogram) support the obtained results

Socio-emotional competencies of teacher professional development

El principal objetivo de las universidades es educar en términos de adquisición de capacidades, habilidades, competencias y valores, con el fin último de promover el empleo. Numerosos autores han llegado a la conclusión de que la inteligencia emocional forma parte de las competencias que requieren las personas para desarrollar con éxito su labor profesional. En este trabajo se realiza una comparación de perfiles de competencias socioemocionales, mediante un análisis multivariado de la varianza, para el cual se dispuso de la opinión de una muestra de 148 maestros en ejercicio y de la medida en dichas competencias de 139 estudiantes de magisterio. Los resultados indicaron que existen diferencias en los perfiles de ambos grupos; siendo esta diferencia significativa para 11 de las 13 variables socioemocionales analizadas. Los estudiantes tienen menos desarrolladas las competencias socioemocionales que requieren según los profesionales. Parece, por tanto, necesario que desde los currícula universitarios se promueva el desarrollo de estas competencias para un desarrollo profesional eficaz.The main purpose of universities is to educate in terms of knowledge, abilities, skills and values adquisition, with the ultimate aim of promoting employment. Many academics have concluded that intelligence is part of the social-emotional skills needed by individuals to successfully develop their professional work. In this article we undertake an analysis of socio-emotional competence profiles by means of the application of a multivariate procedure to a sample of 148 teachers in exercise and to 139 students in teacher training courses.The results of our analysis show notable differences in the profiles of both groups, the difference being highly significant in 11 of the 13 socio-emotional variables analyzed. Students show a minor development of socio-emotional skills required by professionals. As a main conclusion of our analysis we can state that it reveals imperative that the university curricula promotes the development of these skills in order to achieve an effective professional development.Esta investigación ha sido financiada por el Proyecto de I+D PSI2009-12696 de la Secretaría de Estado de Investigación, con el título: Competencias Intelectuales, Personales y Socioemocionales en la Inserción Laboral de los Egresados Universitarios

What gaze adds to arrows: Changes in attentional response to gaze versus arrows in childhood and adolescence

FPU, Grant/Award Number: fpu16/07124From early ages, gaze acts as a cue to infer the interests, behaviours, thoughts and emotions of social partners. Despite sharing attentional properties with other non-social directional stimuli, such as arrows, gaze produces unique effects. A spatial interference task revealed this dissociation. The direction of arrows was identified faster on congruent than on incongruent direction-location trials. Conversely, gaze produced a reversed congruency effect (RCE), with faster identifications on incongruent than congruent trials. To determine the emergence of these gaze-specific attentional mechanisms, 214 Spanish children (4–17 years) divided into 6 age groups, performed the aforementioned task across three experiments. Results showed stimulus-specific developmental trajectories. Whereas the standard effect of arrows was unaffected by age, gaze shifted from an arrow-like effect at age 4 to a gaze-specific RCE at age 12. The orienting mechanisms shared by gaze and arrows are already present in 4-year olds and, throughout childhood, gaze becomes a special social cue with additional attentional properties. Besides orienting attention to a direction, as arrows would do, gaze might orient attention towards a specific object that would be attentionally selected. Such additional components may not fully develop until adolescence. Understanding gaze-specific attentional mechanisms may be crucial for children with atypical socio-cognitive development.Spanish Government fpu16/0712

La persuasión

Guía para preparar una unidad didáctica sobre Pesuasión en el ámbito de la comunicación audiovisua

Green bond market and sentiment: is there a switching behaviour?

We examine the impact of Twitter sentiment on the returns of four selected bond indices via the selection of relevant threshold variables, such as the S&P 500 Index, the VIX, and the MSCI World Index. If overreaction or underreaction to significant changes in the market occur regularly (De Bondt and Thaler, 1985, 1987; Jegadeesh and Titman, 1993), it is assumed that Twitter users respond with different intensities in the case of rising, falling or rather indeterminable markets. We fail to find evidence that the S&P 500 Index and VIX are relevant in supporting the switching behaviour. However, the MSCI World Index, to a certain extent, causes this relationship to diverge from the linear one. These claims become stronger when lagged and cubic sentiment variables have been included in the panel smooth transition regression (PSTR)S