Quality coding by neural populations in the early olfactory pathway: analysis using information theory

In this article, we analyze the ability of the early olfactory system to detect and discriminate different odors by means of information theory measurements applied to olfactory bulb activity images. We have studied the role that the diversity and number of receptor neuron types play in encoding chemical information. Our results show that the olfactory receptors of the biological system are low correlated and present good coverage of the input space. The coding capacity of ensembles of olfactory receptors with the same receptive range is maximized when the receptors cover half of the odor input space - a configuration that corresponds to receptors that are not particularly selective. However, the ensemble's performance slightly increases when mixing uncorrelated receptors of different receptive ranges. Our results confirm that the low correlation between sensors could be more significant than the sensor selectivity for general purpose chemo-sensory systems, whether these are biological or biomimetic.

Intelligent PCA contribution analysis for quality estimation in batch processes. Application in a sequencing batch reactor for wastewater treatment

En aquest treball, es proposa un nou mètode per estimar en temps real la qualitat del producte final en processos per lot. Aquest mètode permet reduir el temps necessari per obtenir els resultats de qualitat de les anàlisi de laboratori. S'utiliza un model de anàlisi de componentes principals (PCA) construït amb dades històriques en condicions normals de funcionament per discernir si un lot finalizat és normal o no. Es calcula una signatura de falla pels lots anormals i es passa a través d'un model de classificació per la seva estimació. L'estudi proposa un mètode per utilitzar la informació de les gràfiques de contribució basat en les signatures de falla, on els indicadors representen el comportament de les variables al llarg del procés en les diferentes etapes. Un conjunt de dades compost per la signatura de falla dels lots anormals històrics es construeix per cercar els patrons i entrenar els models de classifcació per estimar els resultas dels lots futurs. La metodologia proposada s'ha aplicat a un reactor seqüencial per lots (SBR). Diversos algoritmes de classificació es proven per demostrar les possibilitats de la metodologia proposada.

Sales restriction, quality selection and the mode of competition

A regulator imposing “sales restrictions” on firms competing in oligopolistic markets may enhance quality provision by the firms. Moreover, for most restrictions levels, the impact on quality selection is invariant to the mode of competition

El contrato de servicios y la propuesta de modernización del Código civil español

La Propuesta para la Modernización del Derecho de Obligaciones y Contratos, hecha pública por la Sección Primera, de Derecho Civil, de la Comisión General de Codificación española en 2009, introduce una nueva concepción del contrato civil, de manera especial incorpora el nuevo concepto de cumplimiento contractual que se defiende en los textos legales europeos sobre la compraventa y en el borrador del Commnon Frame of Reference, así como en la normativa europea sobre los Derechos de los consumidores. En este artículo se da cuenta de tales avances en cuanto pueden referirse, no solo al contrato de compraventa, regulado ex novo en la Propuesta, sino también al contrato de servicios. Se propone centrar la mirada también en este contrato y acometer su regulación.

Does privatization spur regulation? Evidence from the regulatory reform of European airports

This paper conducts an empirical analysis of the relationship between privatization and regulation drawing on data from a wide sample of European airports. We find that privatization promotes a shift from basic regulation to a situation of more detailed or non-regulation, depending on the specific characteristics of the privatization process and on the type of airport being privatized. Moreover, we report a significant association between high traffic volumes and more detailed regulation. By contrast, airports where slot allocation is noncoordinated are significantly associated with non-regulation.

Reparar y sustituir cosas en la compraventa : evolución y últimas tendencias

International texts recognise the buyer's right to the repair or replacement if the goods do not conform with the contract, and at the same time, establish exceptions to their application and certain rules of protection for the seller (Art. 46 CISG, Art. 7.2.3 UNIDROIT Principles of International Commercial Contracts, Art.9:102 PECL and Arts. 4:202 y 4:204 (1) PEL S). This approach is a result of a compromise between civil law systems and the common law and it has been widely extended to the regulation of consumer sales over the last decade (Art. 3.3 of the Directive 1999/44/CE, Art. III.-3:302 DCFR, Art. 26 of the proposal for a Directive on Consumer Rights). These norms regulate the different ways of requiring the fulfilment of a contractual obligation from a new paradigm which has little to do with a need to protect the weak consumer which governed the origins of consumer policy in the European Community. Now the idea of the consumer who shall behave economically efficiently prevails in Art. 3.3 of the Directive 1999/44/CE, a norm which is clearly influenced by the international texts and whose transposing into the national legislation of Member States has created important problems for traditional dogmas. In this sense there are still some unclear issues, such as the possibility of replacing in sales of goods of specific nature or second-hand goods, some aspects on the exercise of repair and replacement, and, even, their use as primary remedies rather than a reduction in price or a rescission of the contract. With regard to this, in England the possibility of offering the consumer free choice between these measures if the goods do not conform with the contract has been raised. This is far from the principle of pacta sunt servanda and is clearly contrary to the economic approach of the proposal for a Directive on Consumer Rights. Up to now Spain has limited itself to implementing Art. 3.3 Directive 1999/44/CE into its legal system in almost literal terms and the case law on the issue has completely turned out to be insufficient. By contrast with Germany, the Spanish legislator has not extended the application of the rules of repair and replacement of Directive 1999/44/CE to nonconsumer sales, even though two draft bill proposals along these lines presented by the General Commission for Codifying (“Comisión General de Codificación”), the last one being in January, 2009

Dinámica del heleoplancton en relación a las fluctuaciones hidrológicas en aiguamolls de l’Empordà (NE de la península Ibérica). Propuesta de un método sencillo de monitorización basado en la abundancia de grupos taxonómicos

Monitoring of the 'ecological water quality' in 'Aiguamolls de l’Empordà' Natural Park was carried out between September 1996 and August 1997 . The aim of this sampling programme was to design a simple method for rapid detect changes in water quality due to human activity. These include flow regulation by the Park management, nutrient entries from effluents of a nearby wastewater treatment plant or agricultural fertilising. The proposed method is based on the analysis of the abundance of characteristic taxonomic groups of aquatic invertebrates (heleoplankton). The simplicity of the method is ensured by the use of large taxa which are easier to recognise than species. The functioning of aquatic systems has been modelled by means of correspondence analysis between samples and taxa. Results can be summerized in five environmental conditions with a regular community structure. Dominated by one taxon: cladocerans, ostracods, calanoids, cyclopoids and harpacticoids. The dynamics of both freshwater and brackish lagoons can be modelled as displacements between these five groups of environmental conditions. Nevertheless, the “calanoids situation” and the “harpacticoids situation” occur mainly in brackish lagoons, whereas the “cladocerans situation” occurs mainly in freshwater. The four principal axes of data variation have been respectively identified as nutrient turnover rate, hypertrophy, degree of mineralization of the organic matter and eutrophy. The use of these taxa has been validated by comparison with a model obtained from the species. We conclude that in a highly fluctuating system such as the one here, only persistent situations of eutrophy or hypertrophy must be equated to low 'ecological water quality'

El foment de la creativitat i de l’esperit emprenedor en el context dels ECTS per a les assignatures de primer curs de la Diplomatura de Turisme de la UAB

El present Projecte de millora de la qualitat docent subvencionat pel Departament d’Universitats, Recerca i Societat de la Informació de la Generalitat de Catalunya dins del programa d’ajuts MQD-2006 convocades per l’AGAUR, s’ha desenvolupat amb els alumnes de primer de la Diplomatura de Turisme de l’Escola de Turisme i Direcció Hotelera (EUTDH) de la UAB durant el curs acadèmic 2006-2007, comptant amb la participació de l’equip docent així com amb la col·laboració i implicació directa de la direcció de l’escola. Aquest projecte parteix de la base que el desenvolupament de l’esperit emprenedor entre els estudiants és un pilar fonamental en la seva educació i preparació tant personal com professional per l’entrada amb èxit al mercat laboral. Així doncs, el fet que els estudiants mostrin més iniciativa individual així com més capacitat per buscar solucions als problemes d’una manera creativa i diferent, són aspectes bàsics d’aquest Projecte que preten, a llarg termini, repercutir en la societat, tot formant persones més emprenedores que aportin valor econòmic i social al sector turístic. Amb la finalitat d’assolir els objectius esmentats anteriorment es van realitzar una sèrie d’accions adreçades tant al professorat com a l’alumnat que portessin a canviar les actituds, comportaments i maneres de fer de la “metodologia docent tradicional”. En aquest sentit, s’han revisat les fitxes de les assignatures, tot adaptant les activitats existents o creant-ne de noves per tal de treballar les competències transversals relacionades amb el foment de l’esperit emprenedor. Tot i que aquests canvis són lents i difícils de mesurar, en general, s’ha pogut constatar com l’alumnat, en finalitzar el curs, mostra una major iniciativa, autonomía i independència i més capacitat per buscar solucions alternatives als problemes d’una manera creativa així com una actitud més favorable cap a la creació d’empreses que la que tenia al començament.

The quest for a message: budding yeast, a model organism to study the control of pre-mRNA splicing

Removal of introns during pre-mRNA splicing is a critical process in gene expression, and understanding its control at both single-gene and genomic levels is one of the great challenges in Biology. Splicing takes place in a dynamic, large ribonucleoprotein complex known as the spliceosome. Combining Genetics and Biochemistry, Saccharomyces cerevisiae provides insights into its mechanisms, including its regulation by RNA-protein interactions. Recent genome-wide analyses indicate that regulated splicing is broad and biologically relevant even in organisms with a relatively simple intronic structure, such as yeast. Furthermore, the possibility of coordination in splicing regulation at genomic level is becoming clear in this model organism. This should provide a valuable system to approach the complex problem of the role of regulated splicing in genomic expression.

Comparing and validating hypothesis test procedures: Graphical and numerical tools

When the behaviour of a specific hypothesis test statistic is studied by aMonte Carlo experiment, the usual way to describe its quality is by givingthe empirical level of the test. As an alternative to this procedure, we usethe empirical distribution of the obtained \emph{p-}values and exploit itsinformation both graphically and numerically.

Subjectively adapted high capacity lossless image data hiding based on prediction errors

This article reports on a lossless data hiding scheme for digital images where the data hiding capacity is either determined by minimum acceptable subjective quality or by the demanded capacity. In the proposed method data is hidden within the image prediction errors, where the most well-known prediction algorithms such as the median edge detector (MED), gradient adjacent prediction (GAP) and Jiang prediction are tested for this purpose. In this method, first the histogram of the prediction errors of images are computed and then based on the required capacity or desired image quality, the prediction error values of frequencies larger than this capacity are shifted. The empty space created by such a shift is used for embedding the data. Experimental results show distinct superiority of the image prediction error histogram over the conventional image histogram itself, due to much narrower spectrum of the former over the latter. We have also devised an adaptive method for hiding data, where subjective quality is traded for data hiding capacity. Here the positive and negative error values are chosen such that the sum of their frequencies on the histogram is just above the given capacity or above a certain quality.

Efectos del diseño de la tienda virtual en el comportamiento de compra: tipificación del consumidor online

Cuando una empresa se decide a realizar una iniciativa comercial en Internet, al igual que en el mundo físico, es necesario definir un diseño adecuado del sitio web que se ajuste a su idea de negocio y a su público objetivo. El presente trabajo trata de analizar como influye el diseño del establecimiento virtual en el desarrollo de la gestión comercial, incidiendo en los siguientes aspectos: diseño gráfico, usabilidad y accesibilidad. A partir de este análisis, se estudian los distintos grupos de consumidores con comportamientos homogéneos y se posicionan en función de sus actitudes. El análisis también permite definir la calidad del servicio prestado por este tipo de establecimientos, así como las principales dimensiones en que se despliega. En las conclusiones se citan aspectos en los que el gestor de una tienda online debe incidir para mejorar la calidad de su servicio.

Mouse hepatic oval cells require Met-dependent PI3K to impair TGF-β-Induced oxidative stress and apoptosis.

We have previously shown that oval cells harboring a genetically inactivated Met tyrosine kinase (Met−/− oval cells) are more sensitive to TGF-β-induced apoptosis than cells expressing a functional Met (Metflx/flx), demonstrating that the HGF/Met axis plays a pivotal role in oval cell survival. Here, we have examined the mechanism behind this effect and have found that TGF-β induced a mitochondria-dependent apoptotic cell death in Metflx/flx and Met−/− oval cells, associated with a marked increase in levels of the BH3-only proteins Bim and Bmf. Bmf plays a key role during TGF-β-mediated apoptosis since knocking down of BMF significantly diminished the apoptotic response in Met-/- oval cells. TGF-β also induced oxidative stress accompanied by NADPH oxidase 4 (Nox4) mRNA up-regulation and decreased protein levels of antioxidant enzymes. Antioxidants inhibit both TGF-β-induced caspase 3 activity and Bmf up-regulation, revealing an oxidative stress-dependent Bmf regulation by TGF-β. Notably, oxidative stress-related events were strongly amplified in Met−/− oval cells, emphasizing the critical role of Met in promoting survival. Pharmacological inhibition of PI3K did impair HGF-driven protection from TGF-β-induced apoptosis and increased sensitivity of Metflx/flx oval cells to TGF-ß by enhancing oxidative stress, reaching apoptotic indices similar to those obtained in Met−/− oval cells. Interestingly, both PI3K inhibition and/or knockdown itself resulted in caspase-3 activation and loss of viability in Metflx/flx oval cells, whereas no effect was observed in Met−/− oval cells. Altogether, results presented here provide solid evidences that both paracrine and autocrine HGF/Met signaling requires PI3K to promote mouse hepatic oval cell survival against TGF-β-induced oxidative stress and apoptosis.

Estudi sobre la qualitat percebuda dels usuaris de serveis socials bàsics de la ciutat de Lleida: Centre de Democràcia i Cappont

Aquesta activitat es centra en l’estudi de la qualitat percebuda per part dels usuaris de serveis socials bàsics de la ciutat de Lleida. L’anàlisi s’ha basat en dos centres en concret, Democràcia i Cappont. Per a l’elaboració d’aquesta investigació, s’han combinat tècniques quantitatives i qualitatives. Per una banda, s’ha utilitzat l’escala SERVQUAL per conèixer la percepeció que tenen les persones usuàries dels serveis esmentats i per l’altra, s’han realitzat entrevistes a estudiants del grau de Treball Social que han fet les pràctiques als centres estudiats. Els resultats, ens han servit per poder observar els elements més ben valorats i els aspectes sobre els quals cal incidir per millorar l’atenció. Finament, hem exposat quines creiem que són les modificacions que caldria introduir i quins són els aprenentatges personals d’aquesta investigació.

Large Magnetoresistance in Fe/MgO/FeCo(001) Epitaxial Tunnel-Junctions on GaAs(001).

We present tunneling experiments on Fe~001!/MgO~20 Å!/FeCo~001! single-crystal epitaxial junctions of high quality grown by sputtering and laser ablation. Tunnel magnetoresistance measurements give 60% at 30 K, to be compared with 13% obtained recently on ~001!-oriented Fe/amorphous-Al2O3 /FeCo tunnel junctions. This difference demonstrates that the spin polarization of tunneling electrons is not directly related to the density of states of the free metal surface Fe~001! in this case but depends on the actual electronic structure of the entire electrode/barrier system.