Aflatoxines i ocratoxines: agents tòxics que cal controlar

El present article se centra en l'estudi de toxines produïdes per fongs dels gèneres Aspergillus i Penicillium, més concretament en les aflatoxines B1, G1, B2, G2 i ocratoxina A. Es dóna una visió general del tema quant a origen, legislació, toxicitat i control de micotoxines. A més, es presenten tres mètodes per a l'anàlisi d'aquestes toxines en productes vegetals, ja que són els substrats en els quals es presenten més habitualment. Primerament, es desenvolupa un metòde d'anàlisi per a la determinació d'aflatoxines B1, G1, B2 i G2 en una planta medicinal. Posteriorment, s'optimitza l'anàlisi d'ocratoxina A en cafè i finalment es presenta un mètode per a la determinació simultània d'aflatoxines B1, G1, B2, G2 i ocratoxina A en cervesa. En tots els mètodes s'empra extracció en fase sòlida de reblert polimèric i cromatografia líquida de fase inversa. La detecció es realitza per espectrometria de masses de quadrupol simple amb ionització a pressió atmosfèrica.This paper is focused on the study of mycotoxins produced by fungi of the genera Aspergillus and Penicillium, specifically on aflatoxins B1, G1, B2, G2 and ochratoxin A. A general survey of mycotoxin origin, toxicity, legislation and control is presented. Furthermore, three analytical methods for the analysis of mycotoxins in vegetable products is presented, due to these substrates are the most liable to be contaminated. First, a method for the determination of aflatoxins B1, G1, B2 and G2 in a medicinal herb is presented. Afterwards, the analysis of ochratoxin A in coffee was optimized. Finally, a method for the simultaneous analysis of aflatoxins B1, G1, B2, G2 and ochratoxin A in beer is developed. All the methods apply solid-phase clean-up using a polymeric sorbent and liquid chromatography with a reversed phase column. A single quadruple mass spectrometer with an electrospray ionization source was used as a detector

Assessment of the last-in-first out principle of access for managing the connection of distributed wind generators

Recent projects in the UK have investigated different connection arrangements for managing distributed wind generators to maintain thermal limits and a number of principle of access for generators to the limited distribution network capacity have been investigated. However, principle of access to manage voltage limits have not received as much attention. This study aims to evaluate the current practice for connecting ‘non-firm’ distributed wind generators under both voltage and thermal constraint conditions. It addresses the issue by developing a representative model of a UK 11kV radial distribution feeder comprising a mix of urban and rural sections using time-step optimal power flow simulations. The results indicated that when the principle is applied under both network constraint conditions, it can lead to inefficient use of network capacities and reduced renewable energy yields

A methodology for transient state estimation based on numerical derivatives, optimal monitoring and filtered measurements

This paper proposes a methodology for transient state estimation in power systems. The proposed methodology is formulated using approximation methods for derivatives to relate the state variables to measurements. It does not require knowledge of the steady state to establish the pre-disturbance operation conditions. The method uses an optimal monitoring system based on topological analysis to obtain full observability. A saving index is introduced to analyze the effectiveness of the instrumentation used. The adverse effect of noisy measurements in the estimation process is mitigated using an Infinite Impulse Response (IIR) filter. A transient index is introduced to estimate the fault location. The transient state estimation is assessed using two test systems. The results are validated through direct comparison against those obtained by simulation using SimPowerSystems toolbox of Simulink®. With the proposed methodology, the transient state estimation can be obtained with an important saving in the implementation of the measuring system and with considerably less computational effort

Estudio comparativo de las herramientas MetaCASE bajo consistencia y refinamiento*

Las herramientas MetaCASE surgieron como una evolución de la tecnología CASE, para superar algunas de las limitaciones identificables en este tipo de tecnologías. Estas herramientas poseen mecanismos que permiten la creación y modificación de paradigmas de metamodelamiento, además de la adición de restricciones que se pueden emplear en chequeos de consistencia o transformaciones de refinamiento. En el artículo que aquí se presenta, se realiza un estudio comparativo de cinco herramientas MetaCASE (AToM3, DOME, GME, MetaEdit+ y UN-MetaCASE), tomando en cuenta dos puntos de vista: características generales y capacidades para la realización de chequeos de consistencia y transformaciones de refinamiento. El artículo concluye con un análisis comparativo de dichas herramientas

Management of pregnancy in patients with exstrophy-epispadias sequence: a case series and literature review

Exstrophy-epispadias sequence is an uncommon diagnosis in which surgical reconstruction has increased quality of life for these patients. As they are entering the reproductive phase of their life, consideration must be made for management of their pregnancies in the context of their genitourinary reconstruction. There have been few case reports of patients with cloacal exstrophy conceiving; therefore, information to guide management of their pregnancies is limited. Here we describe a patient with Omphalocele-Exstrophy-Imperforate Anus-Spinal defects (OEIS) and a patient with a history of bladder exstrophy both with spontaneous pregnancy managed by a multidisciplinary approach and primary cesarean delivery

Localization and Capacitance Fluctuations in Disordered Au Nano-junctions

Nano-junctions, containing atomic-scale gold contacts between strongly disordered leads, exhibit different transport properties at room temperature and at low temperature. At room temperature, the nano-junctions exhibit conductance quantization effects. At low temperatures, the contacts exhibit Coulomb-Blockade. We show that the differences between the room-temperature and low temperature properties arise from the localization of electronic states in the leads. The charging energy and capacitance of the nano-junctions exhibit strong fluctuations with applied magnetic field at low temperature, as predicted theoretically.Comment: 20 pages 8 figure

Loosenin, a novel protein with cellulose-disrupting activity from Bjerkandera adusta

<p>Abstract</p> <p>Background</p> <p>Expansins and expansin-like proteins loosen cellulose microfibrils, possibly through the rupture of intramolecular hydrogen bonds. Together with the use of lignocellulolytic enzymes, these proteins are potential molecular tools to treat plant biomass to improve saccharification yields.</p> <p>Results</p> <p>Here we describe a new type of expansin-related fungal protein that we have called loosenin. Its corresponding gene, <it>loos1</it>, from the basidiomycete <it>Bjerkandera adusta</it>, was cloned and heterologously expressed in <it>Saccharomyces cerevisiae</it>. LOOS1 is distantly related to plant expansins through the shared presence of a DPBB domain, however domain II found in plant expansins is absent. LOOS1 binds tightly to cellulose and chitin, and we demonstrate that cotton fibers become susceptible to the action of a commercial cellulase following treatment with LOOS1. Natural fibers of <it>Agave tequilana </it>also become susceptible to hydrolysis by cellulases after loosenin treatment.</p> <p>Conclusions</p> <p>LOOS1 is a new type of protein with disrupting activity on cellulose. LOOS1 binds polysaccharides, and given its enhancing properties on the action of hydrolytic enzymes, LOOS1 represents a potential additive in the production of fermentable sugars from lignocellulose.</p

Geometry of Goodness-of-Fit Testing in High Dimensional Low Sample Size Modelling

We introduce a new approach to goodness-of-fit testing in the high dimensional, sparse extended multinomial context. The paper takes a computational information geometric approach, extending classical higher order asymptotic theory. We show why the Wald – equivalently, the Pearson X2 and score statistics – are unworkable in this context, but that the deviance has a simple, accurate and tractable sampling distribution even for moderate sample sizes. Issues of uniformity of asymptotic approximations across model space are discussed. A variety of important applications and extensions are noted

Computational information geometry in statistics: foundations

This paper lays the foundations for a new framework for numerically and computationally applying information geometric methods to statistical modelling

Incidencia de las nuevas tecnologías en el valor percibido de los servicios en el sector de la comunicación en Aragón

El sector de las empresas de comunicación, considerando como tales tanto medios como agencias de publicidad, ha cambiado enormemente sus prácticas profesionales durante la última década y el valor de los servicios que ofrecen a los anunciantes y a usuarios está en entredicho. Esta investigación estudia la incidencia de la tecnología en los cambios producidos en la estructura competitiva del sector, utilizando como estudio de caso Aragón (España). Mediante la triangulación metodológica, analizamos datos de los principales informes nacionales e internacionales, las percepciones de los profesionales, anunciantes y usuarios. En el presente estudio, proponemos un marco contextual a los decisores estratégicos, que no solo describe la situación actual, sino que permite vislumbrar tendencias. Funciones que tradicionalmente eran asumidas por las agencias de publicidad se han internalizado, tanto en las empresas anunciantes como en los medios de comunicación, ante la facilidad de implementación que ofrecen los nuevos canales de comunicación. Tanto los medios convencionales como los nuevos soportes publicitarios digitales llegan ahora de forma directa a las empresas anunciantes, eliminando de esta forma todo lo que es percibido como intermediación sin valor añadido. En un contexto tecnológico en el que se han reducido enormemente los costes de información y de transacción, es hora de que cada agente económico reflexione sobre su aportación real en la cadena de valor. Mediante esta investigación, hemos aportado algunas claves que pueden ayudar a quienes deban tomar este tipo de decisiones, sean medios o agencias, a comprender los procesos de decisión de sus clientes. During the last decade, the communication companies sector, considering as such both media and advertising agencies, has greatly changed professional practices. The value of the services offered to advertisers and users is being compromised. This research studies the incidence of technology in the changes in the sector's competitive structure, using Aragon (Spain) as a case study. Through methodological triangulation, we analyze data from the main national and international reports, the impressions of professionals, advertisers and users. In the present study, we propose a contextual framework for strategic decision-makers. It not only describes the current situation, but also allows for a glimpse at trends. Functions that, traditionally, were taken on board by publicity agencies have been internalized, both in the advertising companies and in the media, given the ease of implementation offered by the new communication channels. Now, both conventional media and new digital advertising media reach advertisers directly, eliminating what is perceived as intermediation without added value. In a technological context in which the costs of information and transactions have been greatly reduced, it is time for each economic agent to reflect on his real contribution in the value chain. With our research, we have put forward some key factors that allow assistance for those who should take that kind of decisions, whether media or agencies, in order to understand their customers' decision-making processes