Photodamage to Oxygen Evolving Complex - An Initial Event in Photoinhibition of Photosystem II.

Photosystem II (PSII) of oxygenic photosynthesis is susceptible to photoinhibition. Photoinhibition is defined as light induced damage resulting in turnover of the D1 protein subunit of the reaction center of PSII. Both visible and ultraviolet (UV) light cause photoinhibition. Photoinhibition induced by UV light damages the oxygen evolving complex (OEC) via absorption of UV photons by the Mn ion(s) of OEC. Under visible light, most of the earlier hypotheses assume that photoinhibition occurs when the rate of photon absorption by PSII antenna exceeds the use of the absorbed energy in photosynthesis. However, photoinhibition occurs at all light intensities with the same efficiency per photon. The aim of my thesis work was to build a model of photoinhibition that fits the experimental features of photoinhibition. I studied the role of electron transfer reactions of PSII in photoinhibition and found that changing the electron transfer rate had only minor influence on photoinhibition if light intensity was kept constant. Furthermore, quenching of antenna excitations protected less efficiently than it would protect if antenna chlorophylls were the only photoreceptors of photoinhibition. To identify photoreceptors of photoinhibition, I measured the action spectrum of photoinhibition. The action spectrum showed resemblance to the absorption spectra of Mn model compounds suggesting that the Mn cluster of OEC acts as a photoreceptor of photoinhibition under visible light, too. The role of Mn in photoinhibition was further supported by experiments showing that during photoinhibition OEC is damaged before electron transfer activity at the acceptor side of PSII is lost. Mn enzymes were found to be photosensitive under visible and UV light indicating that Mn-containing compounds, including OEC, are capable of functioning as photosensitizers both in visible and UV light. The experimental results above led to the Mn hypothesis of the mechanism of continuous-light-induced photoinhibition. According to the Mn hypothesis, excitation of Mn of OEC results in inhibition of electron donation from OEC to the oxidized primary donor P680+ both under UV and visible light. P680 is oxidized by photons absorbed by chlorophyll, and if not reduced by OEC, P680+ may cause harmful oxidation of other PSII components. Photoinhibition was also induced with intense laser pulses and it was found that the photoinhibitory efficiency increased in proportion to the square of pulse intensity suggesting that laser-pulse-induced photoinhibition is a two-photon reaction. I further developed the Mn hypothesis suggesting that the initial event in photoinhibition under both continuous and pulsed light is the same: Mn excitation that leads to the inhibition of electron donation from OEC to P680+. Under laser-pulse-illumination, another Mn-mediated inhibitory photoreaction occurs within the duration of the same pulse, whereas under continuous light, secondary damage is chlorophyll mediated. A mathematical model based on the Mn hypothesis was found to explain photoinhibition under continuous light, under flash illumination and under the combination of these two.

Visuo-motor pathways in humans revealed by event-related fMRI.

Whether different brain networks are involved in generating unimanual responses to a simple visual stimulus presented in the ipsilateral versus contralateral hemifield remains a controversial issue. Visuo-motor routing was investigated with event-related functional magnetic resonance imaging (fMRI) using the Poffenberger reaction time task. A 2 hemifield x 2 response hand design generated the "crossed" and "uncrossed" conditions, describing the spatial relation between these factors. Both conditions, with responses executed by the left or right hand, showed a similar spatial pattern of activated areas, including striate and extrastriate areas bilaterally, SMA, and M1 contralateral to the responding hand. These results demonstrated that visual information is processed bilaterally in striate and extrastriate visual areas, even in the "uncrossed" condition. Additional analyses based on sorting data according to subjects' reaction times revealed differential crossed versus uncrossed activity only for the slowest trials, with response strength in infero-temporal cortices significantly correlating with crossed-uncrossed differences (CUD) in reaction times. Collectively, the data favor a parallel, distributed model of brain activation. The presence of interhemispheric interactions and its consequent bilateral activity is not determined by the crossed anatomic projections of the primary visual and motor pathways. Distinct visuo-motor networks need not be engaged to mediate behavioral responses for the crossed visual field/response hand condition. While anatomical connectivity heavily influences the spatial pattern of activated visuo-motor pathways, behavioral and functional parameters appear to also affect the strength and dynamics of responses within these pathways.

Visualitzador de molècules d'ADN per laboratori virtual

RESUM Com a continuació del treball de final de carrera “Desenvolupament d’un laboratori virtual per a les pràctiques de Biologia Molecular” de Jordi Romero, s’ha realitzat una eina complementaria per a la visualització de molècules integrada en el propi laboratori virtual. Es tracta d’una eina per a la visualització gràfica de gens, ORF, marques i seqüències de restricció de molècules reals o fictícies. El fet de poder treballar amb molècules fictícies és la gran avantatge respecte a les solucions com GENBANK que només permet treballar amb molècules pròpies. Treballar amb molècules fictícies fa que sigui una solució ideal per a l’ensenyament, ja que dóna la possibilitat als professors de realitzar exercicis o demostracions amb molècules reals o dissenyades expressament per a l’exercici a demostrar. A més, permet mostrar de forma visual les diferents parts simultàniament o per separat, de manera que ofereix una primera aproximació interpretació dels resultats. Per altra banda, permet marcar gens, crear marques, localitzar seqüències de restricció i generar els ORF de la molècula que nosaltres creem o modificar una ja existent. Per l’implementació, s’ha continuat amb l’idea de separar la part de codi i la part de disseny en les aplicacions Flash. Per fer-ho, s’ha utilitzat la plataforma de codi lliure Ariware ARPv2.02 que proposa un marc de desenvolupament d’aplicacions Flash orientades a objectes amb el codi (classes ActionScript 2.0) separats del movieclip. Per al processament de dades s’ha fet servir Perl per ser altament utilitzat en Bioinformàtica i per velocitat de càlcul. Les dades generades es guarden en una Base de Dades en MYSQL (de lliure distribució), de la que s’extreuen les dades per generar fitxers XML, fent servir tant PHP com la plataforma AMFPHP com a enllaç entre Flash i la resta de parts.

Creació d'una botiga virtual i automatització dels albarans, factures i cobraments

L’augment de la utilització de les noves tecnologies a la nostra societat permet a les empreses arribar al client d’una forma més rapida i facilitant la informació de manera àgil i ordenada. Amb aquest objectiu s’ha creat una botiga virtual que serà la part visible als usuaris i clients de l’empresa PRINTONER S.L , dedicada al sector dels consumibles, especialment els reciclats. Per l’empresa un dels objectius principals és oferir al client la possibilitat de comprar els seus productes de manera còmode a través d’Internet, ja que accedint amb un nom d’usuari i una contrasenya podrà obtenir totes les referències de les que es disposa, podrà tramitar les comandes i controlar-ne l’estat fins el moment de l’entrega. A part de les seccions destinades a usuaris i clients s’ha creat una zona d’administració, on els responsables de l’empresa podran gestionar tots els productes, modificar i visualitzar les comandes. A més aprofitant que aquestes quedaran guardades a una base de dades juntament amb els productes venuts, s’integrarà el sistema de facturació de l’empresa, cosa que fins el moment es feia de manera manual i maldestre. També es programarà una part on els responsables podran insertar reparacions i vendes informàtiques que s’hagin de facturar o per fer-ne un us estadístic en un futur. Tot això ens portarà a implementar un sistema d’usuaris registrats amb diferents permisos i diferents nivells d’accés a l’aplicació, fins a un total de 5. S’ha intentat fer de l’aplicació, un sistema a mida i que compleixi tots els requisits que l’empresa ens ha demanat, amb la previsió que més endavant s’hi pugui implementar un sistema de gestió d’estocs i altres millores per oferir als seus clients un servei inigualable. Per tal de portar a terme tot aquest treball s’ha utilitzat una tecnologia de lliure distribució com és el llenguatge PHP i la base de dades MySQL, aquesta opció a part d’una filosofia es produeix per intentar minimitzar els costos de l’aplicatiu. La finalitat de l’empresa amb aquest projecte és oferir millor imatge i servei, efectivitat i rapidesa en tot el procés de vendes, així com reduir costos de facturació i també de publicitat, ja que es podrà potenciar molt més la pàgina web via internet.

Teclat virtual amb predicció del llenguatge

L'objectiu de la realització d'aquest treball és la creació d'un teclat virtual destinat a ajudar a persones amb mobilitat reduïda, que no poden utilitzar el teclat físic de l'ordinador, a escriure intentant aconseguir una velocitat d'escriptura raonable per a textos de qualsevol mida. Per aconseguir aquesta velocitat d'escriptura raonable s'ha implementat un sistema de predicció del llenguatge que té dos aspectes. D'una banda es prediuen paraules segons la seva freqüència d'ús en un determinat diccionari i, d'altra banda, es prediuen paraules seguint les regles d'escriptura de la gramàtica catalana. Un altre aspecte important era que el programa creat es pogués utilitzar en diferents sistemes operatius ja que només hi havia versions específiques per a cada un d'ells. El programa creat es pot executar en els sistemes operatius Windows XP, Mac OS i Ubuntu Linux. El programa creat pretén ser una base per a posteriors millores i ampliacions en diferents parts del seu conjunt. No obstant això, com a resultat s'ha obtingut un programa que permet escriure raonablement ràpid i permet a l'usuari gestionar diccionaris i els dos tipus de predicció que s'han implementat.

Mort des voyageurs: risques réels, risques virtuels [True and virtual risks of travellers].

Evidence-based information on travel associated mortality is scarce. Perception, intuition and the availability of interventions such as vaccinations and chemoprophylaxis often guide pre-travel advice. Important risks including accidents and cardiovascular events are not routinely included in pre-travel consultations although they cause more fatalities and costs than infectious diseases. The increased risk of sustaining a road accident in poor economy countries should always be mentioned. The general practitioner is further best placed to discuss possible problems of travellers with chronic diseases before travel.

Single-trial topographic analysis of human EEG: A new image of event-related potentials

We present a novel approach for analyzing single-trial electroencephalography (EEG) data, using topographic information. The method allows for visualizing event-related potentials using all the electrodes of recordings overcoming the problem of previous approaches that required electrode selection and waveforms filtering. We apply this method to EEG data from an auditory object recognition experiment that we have previously analyzed at an ERP level. Temporally structured periods were statistically identified wherein a given topography predominated without any prior information about the temporal behavior. In addition to providing novel methods for EEG analysis, the data indicate that ERPs are reliably observable at a single-trial level when examined topographically.

A limited area model intercomparison on the "Montserrat-2000" flash-flood event using statistical and deterministic methods

In the scope of the European project Hydroptimet, INTERREG IIIB-MEDOCC programme, limited area model (LAM) intercomparison of intense events that produced many damages to people and territory is performed. As the comparison is limited to single case studies, the work is not meant to provide a measure of the different models' skill, but to identify the key model factors useful to give a good forecast on such a kind of meteorological phenomena. This work focuses on the Spanish flash-flood event, also known as "Montserrat-2000" event. The study is performed using forecast data from seven operational LAMs, placed at partners' disposal via the Hydroptimet ftp site, and observed data from Catalonia rain gauge network. To improve the event analysis, satellite rainfall estimates have been also considered. For statistical evaluation of quantitative precipitation forecasts (QPFs), several non-parametric skill scores based on contingency tables have been used. Furthermore, for each model run it has been possible to identify Catalonia regions affected by misses and false alarms using contingency table elements. Moreover, the standard "eyeball" analysis of forecast and observed precipitation fields has been supported by the use of a state-of-the-art diagnostic method, the contiguous rain area (CRA) analysis. This method allows to quantify the spatial shift forecast error and to identify the error sources that affected each model forecasts. High-resolution modelling and domain size seem to have a key role for providing a skillful forecast. Further work is needed to support this statement, including verification using a wider observational data set.

Radar analysis of the life cycle of mesoscale convective systems during the 10 June 2000 event

The 10 June 2000 event was the largest flash flood event that occurred in the Northeast of Spain in the late 20th century, both as regards its meteorological features and its considerable social impact. This paper focuses on analysis of the structures that produced the heavy rainfalls, especially from the point of view of meteorological radar. Due to the fact that this case is a good example of a Mediterranean flash flood event, a final objective of this paper is to undertake a description of the evolution of the rainfall structure that would be sufficiently clear to be understood at an interdisciplinary forum. Then, it could be useful not only to improve conceptual meteorological models, but also for application in downscaling models. The main precipitation structure was a Mesoscale Convective System (MCS) that crossed the region and that developed as a consequence of the merging of two previous squall lines. The paper analyses the main meteorological features that led to the development and triggering of the heavy rainfalls, with special emphasis on the features of this MCS, its life cycle and its dynamic features. To this end, 2-D and 3-D algorithms were applied to the imagery recorded over the complete life cycle of the structures, which lasted approximately 18 h. Mesoscale and synoptic information were also considered. Results show that it was an NS-MCS, quasi-stationary during its stage of maturity as a consequence of the formation of a convective train, the different displacement directions of the 2-D structures and the 3-D structures, including the propagation of new cells, and the slow movement of the convergence line associated with the Mediterranean mesoscale low.

Laboratorio virtual de software libre para bibliotecas

La elección de un programa de gestión de bibliotecas se ve afectada muchas veces por una serie de condiciones sociales, económicas y políticas que hacen que la elección no sea la más adecuada para las necesidades, características y funciones de la biblioteca. El software libre está siendo una de las soluciones más optadas, por sus libertades de copia, modificación y distribución, además de la libertad de licencias y las posibilidades de interoperación con otras aplicaciones. Esta nueva tendencia hacia el software libre en bibliotecas se refleja también en los estudios de biblioteconomía y documentación, en los que desde diferentes asignaturas se aportan conocimientos sobre programas de automatización, de gestión de repositorios, incluso del sistema operativo Linux/GNU, entre otros. Esta combinación entre las necesidades de los centros y la tendencia al uso de software libre, es la que un grupo de profesores de la Facultat de Biblioteconomia i Documentació (Universitat de Barcelona) y estudiantes, miembros del Grup de Treball sobre Programari Lliure per als Professionals de la Informació (Cobdc), han querido aportar a la comunidad profesional, creando un laboratorio virtual para el uso de software libre de aplicación en bibliotecas.

A virtual exhibition of open source software for libraries

Frequently the choice of a library management program is conditioned by social, economic and/or political factors that result in the selection of a system that is not altogether suitable for the library’s needs, characteristics and functions. Open source software is quickly becoming a preferred solution, owing to the freedom to copy, modify and distribute it and the freedom from contracts, as well as for greater opportunities for interoperability with other applications. These new trends regarding open source software in libraries are also reflected in LIS studies, as evidenced by the different courses addressing automated programs, repositorymanagement, including the Linux/GNU operating system, among others. The combination of the needs of the centres and the new trends for open source software is the focus of a virtual laboratory for the use of open source software for library applications. It was the result of a project, whose aim was to make a useful contribution to the library community, that was carried out by a group of professors of the School of Library and Information Science of the University of Barcelona, together with a group of students, members of a Working Group on Open Source Software for Information Professionals, of the Professional Library Association of Catalonia.