Determinación de ácido quinolínico en corteza renal de rata

Se describe una modificación al método descrito por McDaniel y col. (8) para la determinación de ácido quinolínico en diferentes tejidos animales. El método consiste en la extracción con ácido perclórico, adsorción selectiva sobre carbón activado y descarboxilación hasta ácido nicotínico, que se mide colorimétricamente. Con este método se han medido las concentraciones de ácido qUinolínico en corteza renal tras la administración de triptófano a las ratas, encontrándose que ninguno de los valores es suficiente para producir una inhibición de la fosfoenolpiruvato carboxicinasa y por tanto de la capacidad gluconeogénica renal.We have described a method based on McDaniel's (8) for the determination of quinolinic acid in several animal tissues. The method consist in the extraction of quinolinic acid, selective adsortion on activated charco al and decarboxylation to nicotinic acid which have been measured by colorimetric reaction. With this method we have measured the concentrations of quinolinic acid in rat renal cortex after the tryptophan injection to rato We have found that anyone of values is enough to make an inhibition of phosphoenol pyruvate carboxykinase activity and t he renal gluconeogenic capacity

Assessing attention deficit by binocular rivalry

Objective: To determine whether the frequency and duration of the periods of suppression of a percept in a binocular rivalry (BR) task can be used to distinguish between subjects with attention deficit hyperactivity disorder (ADHD) and controls. Method: 122 participants (6 to 15 years) were assigned to three groups: ADHD Combined (ADHD-C), ADHD-Predominantly Inattentive (ADHD-I) and controls. They each performed a BR task and two measures were recorded: alternation rate and duration of exclusive dominance periods. Results: ADHD-C group presented fewer alternations and showed greater variability than did the control group; results for the ADHD-I group being intermediate between the two. The duration of dominance periods showed a differential profile: in control group it remained stable over time, whereas in the clinical groups it decreased logarithmically as the task progressed. Conclusions: The differences between groups in relation to the BR indicators can be attributed to the activity of involuntary inhibition

Analysis of the Utilization of Air-Cooled Blast Furnace Slag as Industrial Waste Aggregates in Self-Compacting Concrete

In this work, the effects of replacing the aggregates of self-compacting concrete by air-cooled blast furnace slag have been analysed. Different mixes have been manufactured by substituting the fine and coarse natural aggregates by air-cooled blast furnace slag. The fracture energy and the tensile and compressive strength have been determined for each mix. The self-compacting properties of the mixes, or the absence of them, have been observed. The main goals of this research are the decrease of the price of aggregates, reduction of the industrial waste, and attenuation the rate of consumption of natural resources. The results show that the self-compactability of the concrete is gradually lost as the slag content is increased, thus, when the ratio of replacement is low, the concrete keeps the self-compacting properties. Nevertheless, the loss of self-compaction affects the mechanical properties by increasing its strength. An air-cooled blast furnace slag did not present problems of heavy metals leaching.Ministerio de Economía y Competitividad BIA2016-75431-RUniversidad de Sevilla VI Plan Propio de Investigació

Psychometric properties of a test for ADHD based on binocular rivalry

The psychometric properties of a Binocular Rivalry (BR)-based test on a group of 159 participants (57 with attention deficit hyperactivity disorder, ADHD) aged between 6 and 15 years are presented. Two factors, which explained 56.82% of the variance, were obtained by exploratory factor analysis: (a) Alternations and Duration of exclusive dominances, and (b) Decision time. Reliability was excellent (Cronbach's á = .834 and .884). The ADHD group showed fewer alternations and longer duration of dominances and decision time than the control group. Correlations between measures of BR, IQ, working memory, and processing speed of the WISC-IV, and ADHD symptoms, assessed by parents and teachers, ranged between low and medium

Complex interactions in microbial food webs : stoichiometric and functional approaches

The food web structure in some high mountain lakes deviates from the established tendency of high heterotrophic bacteria: phytoplankton biomass ratios in oligotrophic ecosystems. Thus, the microbial food web in La Caldera Lake is weakly developed, and bacteria constitute a minor component of the plankton community in terms of abundance, biomass and production. Autotrophic picoplankton is absent, and heterotrophic microbial food web is weakly developed compared to a grazing chain dominated by calanoid copepods and a phytoplankton community mainly composed of mixotrophic flagellates. In order to explain the singular food web structure of this lake, functional, stoichiometric and taxonomical approaches are followed to assess, on various temporal and spatial scales, the relevance of stressful abiotic factors (ultraviolet solar radiation and P-limitation) on the structure and functioning of this ecosystem. P-availability was the main factor controlling the algal biomass whereas bacterial P- limitation was a transient phenomenon. The algae-bacteria relationship was predominately commensalistic. In contrast to algae, full-sunlight radiation had no negative effect on bacterial growth but rather enhanced bacterial dependence on the carbon released by algae. The prevalence of the commensalistic-mutualistic relationship and the development of a more complex microbial food web were related to the stoichiometry of algae and bacteria (N:P ratios). The microbial food web only developed at balanced algal and bacterial N:P ratios, with the appearance of ciliates after a nutrient pulse. However, mixotrophic algae dominated the planktonic community under P-deficit conditions, and they were the main factor controlling bacterioplankton. Their regulatory effect has a dual nature: (i) a resource-based control, where bacteria depend on the photosynthetic carbon released by algae, i.e., a commensalistic interaction ("without you I cannot live"); and (ii) a predatory control, where bacteria is a prey for mixotrophs ("with you I die"). Hence, the niche of microheterotrophs (nanoflagellates and ciliates) is occupied by mixotrophs, and there is a resulting simplification of the planktonic structure. With respect to the carbon cycle, mixotrophic bacterivory constitutes a "by-pass" for the flux of C towards the grazing chain, precluding the development of a complex heterotrophic microbial food web. Mixotrophs thereby improve the energetic transfer efficiency in high mountain lakes through a reduction in the number of trophic levels. Antagonistic effects of UVR x P interactions on the algae-bacteria relationship were caused by an enhancement of dual (resource and predation) control. Based on these results, an alternative model for the flux of C in autotrophic high mountain lakes has been proposed.La estructura de la red trófica en algunos lagos de alta montaña, se aleja de los patrones establecidos para ecosistemas oligotróficos que proponen el predominio de la red trófica microbiana sobre la cadena de pastoreo. Así, en la laguna de La Caldera las bacterias son el componente minoritario de la comunidad planctónica en términos de abundancia, biomasa y producción. El picoplancton autótrofo está ausente y la red microbiana heterotrófica se encuentra escasamente desarrollada frente a una cadena de pastoreo dominada por copépodos calanoides y algas mixotróficas. Para comprender los mecanismos que determinan esta estructura trófica hemos seguido diferentes aproximaciones de análisis: funcional, estequiométrica y taxonómica sobre distintas escalas espaciales y temporales, en relación con los principales factores de estrés abiótico (radiación ultravioleta y limitación por fósforo) que controlan el funcionamiento de los ecosistemas de alta montaña. Nuestros resultados indican que la disponibilidad de fósforo, de forma generalizada, controla la biomasa algal y de manera transitoria la bacteriana, estableciéndose entre ambas comunidades una relación comensalista. La radiación solar completa no afecta negativamente el desarrollo de las bacterias y si el de las algas y potencia la relación de dependencia por el carbono orgánico (comensalismo) entre algas y bacterias. El predominio de la relación comensalista-mutualista y el desarrollo del bucle microbiano esta relacionado con la estequiometría (razón N:P) de algas y bacterias. Así, sólo cuando la razón N:P de algas y bacterias es equilibrada para crecer, un pulso de nutrientes permite el desarrollo del bucle microbiano. En condiciones naturales de déficit de P, sin embargo, existe un predominio de "algas" con metabolismo mixotrófico. Las algas mixotróficas ejercen un efecto regulador dual sobre las bacterias que denominamos Ni contigo ni sin ti, (i) control por depredación, donde las bacterias son consumidas por algas mixotróficas ("contigo me muero"), (ii) control basado en los recursos estableciéndose una relación de dependencia de las bacterias sobre del carbono liberado por las algas ("sin ti no puedo vivir"). La mixotrofia supone un simplificación en la cadena trófica microbiana, donde los mixótrofos ocupan el nicho potencial de nanoflagelados y ciliados. Desde un punto de vista energético implica un cortocircuito en el flujo de energía y un incremento en la eficiencia de transferencia energética en ecosistemas ultraoligotróficos y con alta dosis de radiación ultravioleta (RUV). Los efectos de la interacción entre RUV y pulsos de P tienen un efecto antagónico sobre la interacción alga-bacteria, intensificando la interacción comensal-depredadora. A partir de los resultados obtenidos proponemos un modelo alternativo de flujo de energía para ecosistemas autotróficos de alta montaña

Una experiència de "paga el que vulguis"

En els darrers anys s'estan popularitzant arreu del món les experiències de "paga el que vulguis": un sistema en el que els consumidors decideixen lliurement quant volen pagar per un producte o servei ofert al mercat (incloent-hi la possibilitat de no pagar). Investigadors de la UAB i de la UdG han analitzat empíricament una d'aquestes experiències: El Trato de l'agència de viatges Atrápalo. Els resultats mostren que una majoria dels clients va realitzar pagaments pels serveis gaudits, tot i que d'uns imports modestos. A diferència d'altres experiències profitoses de "paga el que vulguis", amb El Trato només es va ingressar el 5% del preu de mercat del conjunt de productes oferts. Els investigadors expliquen aquest fet per la forma en que es va presentar la campanya.En los últimos años se están popularizando en todo el mundo las experiencias de "paga lo que quieras": un sistema en el que los consumidores deciden libremente cuánto quieren pagar por un producto o servicio ofrecido en el mercado (incluyendo la posibilidad de no pagar). Investigadores de la UAB y la UdG han analizado empíricamente una de estas experiencias: El Trato de la agencia de viajes Atrápalo. Los resultados muestran que una mayoría de los clientes realizó pagos por los servicios disfrutados, aunque de unos importes modestos. A diferencia de otras experiencias provechosas de "paga lo que quieras", con El Trato sólo se ingresó el 5% del precio de mercado del conjunto de los productos ofrecidos. Los investigadores explican este hecho por la forma en que se presentó la campaña

Structural insights into choline-O-sulfatase reveal the molecular determinants for ligand binding

This work was supported by the Spanish Ministry of Science and Innovation/FEDER grants PID2020-116261GB-I00 (JAG) and RTI2018-097991-B-I00 (JLN), Secretaria General de Universidades, Investigacion y Tecnologia, Junta de Andalucia (PY20-00149 and UAL18-BIO-B005-B; ACA) and the University of Granada (grant PPJI2017-1; SMR). Funding for open access charge: Universidad de Granada/CBUA.Choline-O-sulfatase (COSe; EC 3.1.6.6) is a member of the alkaline phosphatase (AP) superfamily, and its natural function is to hydrolyze choline-O-sulfate into choline and sulfate. Despite its natural function, the major interest in this enzyme resides in the landmark catalytic/substrate promiscuity of sulfatases, which has led to attention in the biotechnological field due to their potential in protein engineering. In this work, an in-depth structural analysis of wild-type Sinorhizobium (Ensifer) meliloti COSe (SmeCOSe) and its C54S active-site mutant is reported. The binding mode of this AP superfamily member to both products of the reaction (sulfate and choline) and to a substrate-like compound are shown for the first time. The structures further confirm the importance of the C-terminal extension of the enzyme in becoming part of the active site and participating in enzyme activity through dynamic intra-subunit and inter-subunit hydrogen bonds (Asn146A–Asp500B–Asn498B). These residues act as the ‘gatekeeper’ responsible for the open/closed conformations of the enzyme, in addition to assisting in ligand binding through the rearrangement of Leu499 (with a movement of approximately 5 A ° ). Trp129 and His145 clamp the quaternary ammonium moiety of choline and also connect the catalytic cleft to the C-terminus of an adjacent protomer. The structural information reported here contrasts with the proposed role of conformational dynamics in promoting the enzymatic catalytic proficiency of an enzyme.Spanish Government European Commission PID2020-116261GB-I00 RTI2018-097991-B-I00Secretaria General de UniversidadesJunta de Andalucia PY20-00149 UAL18-BIO-B005-BUniversity of Granada PPJI2017-

Cambio de actitud y comunicación persuasiva: claves para comprender los procesos de captación y conversión a sectas

Referencia de la publicación original: Carmona Gallego, A., Marco Macarro, M.J., Paz Rodríguez, J.I., & Sánchez Medina, J.A. (1989). Cambio de actitud y comunicación persuasiva: claves para comprender los procesos de captación y conversión a sectas. Apuntes de Psicología, 28-29, 33-37.En este trabajo se considera a las sectas como un problema de salud pública. Para comprender esta idea es necesario romper con la noción clásica de que su peligrosidad viene dada por su ideología. El problema radica más bien en su organización y en las técnicas que emplean. Vistas desde esta perspectiva son fácilmente abordables por la psicología, ya que ésta posee desarrollos teóricos que nos permiten su estudio

Professionals faced with participatory intervention. Communication and the subjective dimension

La actitud de los profesionales ante la intervención participativa se focaliza habitualmente desde las relaciones de poder que enmarcan toda intervención social. Este estudio propone ampliar ese foco de análisis. La investigación se ha llevado a cabo en el ámbito de un plan de intervención pública en 16 municipios de una provincia andaluza, en el que se pretendían desarrollar formas participativas de intervención social. En este contexto se han estudiado: 1) las construcciones discursivas de los profesionales en referencia a la intervención participativa; 2) la forma en la que los profesionales y los vecinos representan discursivamente los contextos en los que se quiere intervenir; y 3) las propuestas concretas de intervención que hacen unos y otros. El análisis pone al descubierto la necesidad de desarrollar un marco teórico-analítico más amplio para la comprensión de la intervención participativa: sus condicionantes, consecuencias, catalizadores y bloqueos.Studies that analyse the attitude of professionals when faced with participatory intervention tend to focus on the relationships of power that frame the entire social-intervention process. The research context was a public intervention plan implemented in 16 towns of an Andalusian province, which aims to develop participatory forms of social intervention. In this context the following aspects were studied: 1) the discursive constructions of professionals in relation to participatory intervention; 2) the way in which professionals and residents represent the target intervention contexts discursively; and 3) the specific proposals of intervention made by professionals and residents. Analysis reveals the need to develop a broader theoretical/analytical framework for the understanding of participatory intervention: its conditions, consequences, catalysts and blocking factors.Grupo de Investigación Antropología y Filosofía (SEJ-126). Universidad de Granad

Success versus failure: Efficient heat devices in thermodynamics

J.G.A. acknowledges financial support from University of Salamanca, with Contract No. 0218 463AB01, and A.M. and J.A.W. under Contract No. 18.KB.YF/463A.C.01.[EN]Classical equilibrium thermodynamics provides, in a general way, upper Carnot bounds for the performance of energy converters. Nevertheless, to suggest lower bounds is a much more subtle issue, especially when they are related to a definition of convenience. Here, this issue is investigated in a unified way for heat engines, refrigerators, and heat pumps. First, irreversibilities are weighted in the context of heat reservoir stability for irreversible engines by using the thermodynamic distance between minimum energy and maximum entropy steady states. Some stability coefficients can be related to a majorization process and the obtention of Pareto fronts, linking stability and optimization by means of efficiency and entropy due to correlations between system and reservoirs. Second, these findings are interpreted in a very simple context. A region where the heat device is efficient is defined in a general scheme and, below this zone, the heat device is inefficient in the sense that irreversibilities somehow dominate its behavior. These findings allow for a clearer understanding of the role played by some well-known figures of merit in the scope of finite-time and -size optimization. Comparison with experimental results is provided