Estudio de la percepción de estudiantes de Español como Lengua Extranjera en relación con el uso del correo electrónico en un curso a distancia.

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Modificaciones tecnológicas para mejorar la seguridad y calidad del jamón curado

Se introdujeron varias modificaciones tecnológicas en la elaboración habitual del jamón curado español de cerdo blanco para mejorar su seguridad y calidad, así como para investigar la contribución relativa de los diversos procesos implicados en la calidad sensorial. Las modificaciones introducidas en cada uno de 3 experimentos (a, b, c) fueron: a) inoculación de un cultivo iniciador (CI) en la superficie del producto y el envasado del jamón al vacío durante la etapa de reposo (EV); b) aplicación de una atmósfera modificada con un contenido reducido de oxígeno (AMCRO) (durante la totalidad o la última parte del procesado) en dos procesos que diferían en las humedades relativas aplicadas; c) realización de un estufaje de 4 días a 35ºC y la aplicación repetida de pequeñas cantidades de grasa dorsal líquida sobre la superficie del jamón. En cada experimento, se siguió un diseño experimental de bloques incompletos para bloquear y evaluar el efecto de la materia prima en cada parámetro. La aplicación del CI evitó el crecimiento superficial de hongos, pero modificó el flavor del producto, dando lugar a la aparición de flavores impropios del jamón tradicional, al aumento de la incidencia de la coquera y a la reducción de la intensidad de notas características del mismo como el flavor añejo. Estos efectos fueron debidos a la acción directa del CI pero probablemente también a los cambios que provocó en la superficie del jamón, como la atenuación del "sudado" del jamón. El EV trajo consigo una reducción del crecimiento superficial de mohos; un mayor gradiente de humedad entre el interior y el exterior del jamón; una disminución de la pérdida de peso; un aumento del nitrógeno no proteico y cambios negativos en la textura, aspecto y flavor, como el aumento de la intensidad del velo blanco y del flavor a pienso, el aumento de la incidencia de la coquera y la atenuación del flavor añejo. Estos efectos fueron consecuencia del mayor contenido de humedad a que dio lugar dicha modificación tecnológica, de la potenciación de los efectos negativos del uso del CI, así como a los cambios que provocó en la superficie del jamón. El uso de una ACRO durante todo el proceso provocó un aumento del nitrógeno no proteico, una disminución de la concentración de óxidos de colesterol, un aumento de la intensidad del velo blanco y, en combinación con el uso de humedades relativas bajas, causó una disminución del crecimiento bacteriano y evitó el crecimiento de hongos, levaduras y ácaros en el interior y exterior del jamón y el desarrollo de la coquera. Asímismo, dio lugar a una drástica reducción de la intensidad del flavor del jamón debido a la disminución de la intensidad de la oxidación lipídica. Cuando esta ACRO se aplicó únicamente al final del proceso, se consiguió la eliminación de las formas móviles de los ácaros y la disminución de la intensidad de la coquera y el producto resultante poseía un flavor algo más intenso que aquél sometido a una ACRO durante todo el proceso. El aumento de la temperatura de 25-27 ºC a 35 ºC durante 4 días no tuvo ningún efecto sobre los parámetros estudiados. La aplicación de la grasa líquida en la superficie del jamón evitó el secado excesivo en superficie, previno el desarrollo de la coquera y causó un aumento de la intensidad del flavor añejo y una reducción de la incidencia de notas negativas como el tostado, hechos que indican que la liberación de grasa líquida en el jamón ("sudado") constituye un fenómeno determinante en su calidad sensorial. La materia prima fue el factor que afectó a un mayor número de parámetros.

Incidència de microorganismes i de compostos orgànics volàtils en l'aparició de defectes sensorials en suro

La incidència sobre el suro de defectes sensorials amb descriptors de florit-humitat és un dels principals problemes amb què s'enfronta la indústria surera. Els principals compostos relacionats amb aquest defecte son cloroanisoles, metoxipirazines, geosmina i metilisoborneol. Aquesta recerca s'ha fet amb l'objectiu principal d'aprofundir en els mètodes de determinació de compostos volàtils en suro. S'ha desenvolupat una metodologia basada en la microextracció en fase sòlida i la cromatografia de gasos per a l'anàlisi conjunta d'aquests compostos en macerats de suro. El fet que la majoria dels compostos d'interès tingui un origen microbià ha fet necessari completar les anàlisis químiques amb mètodes de detecció i aïllament dels microorganismes susceptibles de produir-los. S'ha utilitzat un mètode per a l'estudi de la diversitat de fongs i bacteris en mostres de suro basat en l'estudi de marcadors genètics mitjançant l'anàlisi en gradients electroforètics desnaturalitzants. Per últim s'ha avaluat la capacitat de producció de defectes sensorials per microorganismes aïllats de suro utilitzant tècniques olfactomètriques.

Josep Claret: arquitectura i societat

El gironí Josep Claret Rubira (1908-1988), arquitecte de professió i artista-dibuixant de vocació, va obtenir el títol l'any 1933, a l'Escola d'Arquitectura de Barcelona. D'ençà d'aquella data i fins a mitjan dels anys 70, va projectar una quantitat enorme d'edificis de múltiples tipologies i nombrosos plans d'urbanització, arreu de les comarques gironines i menorquines. Amb ideologia primerenca propera a les esquerres catalanistes, es va haver d'adaptar al règim franquista, per poder continuar treballant i vivint a Catalunya. Malgrat que inicialment li deuria costar un gran esforç, el procés d'amotllament el va tenir planer (almenys aparentment), gràcies al seu parentiu -per via matrimonial- amb una família que hi estava estretament vinculada. És autor d'obres d'elevat nivell arquitectònic -amb poques que siguin conegudes i reconegudes- i un clar conformador del paisatge de les seves contrades, fet influent en la societat que hi ha estat habitant i que hi viu encara avui dia. La seva arquitectura és un magnífic exemple del que agradava a les generacions de durant cinc dècades. És també autor d'obres que, moltes vegades, no s'adiuen gens amb el que la Història de l'Arquitectura dóna per bones, però que reflecteixen el gust, les preferències i les prioritats d'una societat determinada.

Modelling European winter wind storm losses in current and future climate

Severe wind storms are one of the major natural hazards in the extratropics and inflict substantial economic damages and even casualties. Insured storm-related losses depend on (i) the frequency, nature and dynamics of storms, (ii) the vulnerability of the values at risk, (iii) the geographical distribution of these values, and (iv) the particular conditions of the risk transfer. It is thus of great importance to assess the impact of climate change on future storm losses. To this end, the current study employs—to our knowledge for the first time—a coupled approach, using output from high-resolution regional climate model scenarios for the European sector to drive an operational insurance loss model. An ensemble of coupled climate-damage scenarios is used to provide an estimate of the inherent uncertainties. Output of two state-of-the-art global climate models (HadAM3, ECHAM5) is used for present (1961–1990) and future climates (2071–2100, SRES A2 scenario). These serve as boundary data for two nested regional climate models with a sophisticated gust parametrizations (CLM, CHRM). For validation and calibration purposes, an additional simulation is undertaken with the CHRM driven by the ERA40 reanalysis. The operational insurance model (Swiss Re) uses a European-wide damage function, an average vulnerability curve for all risk types, and contains the actual value distribution of a complete European market portfolio. The coupling between climate and damage models is based on daily maxima of 10 m gust winds, and the strategy adopted consists of three main steps: (i) development and application of a pragmatic selection criterion to retrieve significant storm events, (ii) generation of a probabilistic event set using a Monte-Carlo approach in the hazard module of the insurance model, and (iii) calibration of the simulated annual expected losses with a historic loss data base. The climate models considered agree regarding an increase in the intensity of extreme storms in a band across central Europe (stretching from southern UK and northern France to Denmark, northern Germany into eastern Europe). This effect increases with event strength, and rare storms show the largest climate change sensitivity, but are also beset with the largest uncertainties. Wind gusts decrease over northern Scandinavia and Southern Europe. Highest intra-ensemble variability is simulated for Ireland, the UK, the Mediterranean, and parts of Eastern Europe. The resulting changes on European-wide losses over the 110-year period are positive for all layers and all model runs considered and amount to 44% (annual expected loss), 23% (10 years loss), 50% (30 years loss), and 104% (100 years loss). There is a disproportionate increase in losses for rare high-impact events. The changes result from increases in both severity and frequency of wind gusts. Considerable geographical variability of the expected losses exists, with Denmark and Germany experiencing the largest loss increases (116% and 114%, respectively). All countries considered except for Ireland (−22%) experience some loss increases. Some ramifications of these results for the socio-economic sector are discussed, and future avenues for research are highlighted. The technique introduced in this study and its application to realistic market portfolios offer exciting prospects for future research on the impact of climate change that is relevant for policy makers, scientists and economists.

Non-genomic signalling of the retinoic X receptor through inhibition of Gq signalling in human platelets

Retinoid X receptors (RXRs) are important transcriptional nuclear hormone receptors, acting as either homodimers or the binding partner for at least one fourth of all the known human nuclear receptors. Functional nongenomic effects of nuclear receptors are poorly understood; however, recently peroxisome proliferator-activated receptor (PPAR) gamma, PPARbeta, and the glucocorticoid receptor have all been found active in human platelets. Human platelets express RXRalpha and RXRbeta. RXR ligands inhibit platelet aggregation and TXA(2) release to ADP and the TXA(2) receptors, but only weakly to collagen. ADP and TXA(2) both signal via the G protein, Gq. RXR rapidly binds Gq but not Gi/z/o/t/gust in a ligand-dependent manner and inhibits Gq-induced Rac activation and intracellular calcium release. We propose that RXR ligands may have beneficial clinical actions through inhibition of platelet activation. Furthermore, our results demonstrate a novel nongenomic mode for nuclear receptor action and a functional cross-talk between G-protein and nuclear receptor signaling families.

Nongenomic signaling of the retinoid X receptor through binding and inhibiting Gq in human platelets

Retinoid X receptors (RXRs) are important transcriptional nuclear hormone receptors, acting as either homodimers or the binding partner for at least one fourth of all the known human nuclear receptors. Functional nongenomic effects of nuclear receptors are poorly understood; however, recently peroxisome proliferator-activated receptor (PPAR) gamma, PPAR beta, and the glucocorticoid receptor have all been found active in human platelets. Human platelets express RXR alpha, and RXR beta. RXR ligands inhibit platelet aggregation and TXA(2) release to ADP and the TXA(2) receptors, but only weakly to collagen. ADP and TXA(2) both signal via the G protein, Gq. RXR rapidly binds Gq but not Gi/z/o/t/gust in a ligand-dependent manner and inhibits Gq-induced Rac activation and intracellular calcium release. We propose that RXR ligands may have beneficial clinical actions through inhibition of platelet activation. Furthermore, our results demonstrate a novel nongenomic mode for nuclear receptor action and a functional cross-talk between G-protein and nuclear receptor signaling families. (C) 2007 by The American Society of Hematology.

A combined statistical and dynamical approach for downscaling large-scale footprints of European windstorms

The occurrence of mid-latitude windstorms is related to strong socio-economic effects. For detailed and reliable regional impact studies, large datasets of high-resolution wind fields are required. In this study, a statistical downscaling approach in combination with dynamical downscaling is introduced to derive storm related gust speeds on a high-resolution grid over Europe. Multiple linear regression models are trained using reanalysis data and wind gusts from regional climate model simulations for a sample of 100 top ranking windstorm events. The method is computationally inexpensive and reproduces individual windstorm footprints adequately. Compared to observations, the results for Germany are at least as good as pure dynamical downscaling. This new tool can be easily applied to large ensembles of general circulation model simulations and thus contribute to a better understanding of the regional impact of windstorms based on decadal and climate change projections.

Estimation of wind storm impacts over Western Germany under future climate conditions using a statistical-dynamical downscaling approach

A statistical–dynamical regionalization approach is developed to assess possible changes in wind storm impacts. The method is applied to North Rhine-Westphalia (Western Germany) using the FOOT3DK mesoscale model for dynamical downscaling and ECHAM5/OM1 global circulation model climate projections. The method first classifies typical weather developments within the reanalysis period using K-means cluster algorithm. Most historical wind storms are associated with four weather developments (primary storm-clusters). Mesoscale simulations are performed for representative elements for all clusters to derive regional wind climatology. Additionally, 28 historical storms affecting Western Germany are simulated. Empirical functions are estimated to relate wind gust fields and insured losses. Transient ECHAM5/OM1 simulations show an enhanced frequency of primary storm-clusters and storms for 2060–2100 compared to 1960–2000. Accordingly, wind gusts increase over Western Germany, reaching locally +5% for 98th wind gust percentiles (A2-scenario). Consequently, storm losses are expected to increase substantially (+8% for A1B-scenario, +19% for A2-scenario). Regional patterns show larger changes over north-eastern parts of North Rhine-Westphalia than for western parts. For storms with return periods above 20 yr, loss expectations for Germany may increase by a factor of 2. These results document the method's functionality to assess future changes in loss potentials in regional terms.

Explosive development of winter storm Xynthia over the subtropical North Atlantic Ocean

In winter of 2009–2010 south-western Europe was hit by several destructive windstorms. The most important was Xynthia (26–28 February 2010), which caused 64 reported casualties and was classified as the 2nd most expensive natural hazard event for 2010 in terms of economic losses. In this work we assess the synoptic evolution, dynamical characteristics and the main impacts of storm Xynthia, whose genesis, development and path were very uncommon. Wind speed gusts observed at more than 500 stations across Europe are evaluated as well as the wind gust field obtained with a regional climate model simulation for the entire North Atlantic and European area. Storm Xynthia was first identified on 25 February around 30° N, 50° W over the subtropical North Atlantic Ocean. Its genesis occurred on a region characterized by warm and moist air under the influence of a strong upper level wave embedded in the westerlies. Xynthia followed an unusual SW–NE path towards Iberia, France and central Europe. The role of moist air masses on the explosive development of Xynthia is analysed by considering the evaporative sources. A lagrangian model is used to identify the moisture sources, sinks and moisture transport associated with the cyclone during its development phase. The main supply of moisture is located over an elongated region of the subtropical North Atlantic Ocean with anomalously high SST, confirming that the explosive development of storm Xynthia had a significant contribution from the subtropics.

Can dynamically downscaled windstorm footprints be improved by observations through a probabilistic approach?

Windstorms are a main feature of the European climate and exert strong socioeconomic impacts. Large effort has been made in developing and enhancing models to simulate the intensification of windstorms, resulting footprints, and associated impacts. Simulated wind or gust speeds usually differ from observations, as regional climate models have biases and cannot capture all local effects. An approach to adjust regional climate model (RCM) simulations of wind and wind gust toward observations is introduced. For this purpose, 100 windstorms are selected and observations of 173 (111) test sites of the German Weather Service are considered for wind (gust) speed. Theoretical Weibull distributions are fitted to observed and simulated wind and gust speeds, and the distribution parameters of the observations are interpolated onto the RCM computational grid. A probability mapping approach is applied to relate the distributions and to correct the modeled footprints. The results are not only achieved for single test sites but for an area-wide regular grid. The approach is validated using root-mean-square errors on event and site basis, documenting that the method is generally able to adjust the RCM output toward observations. For gust speeds, an improvement on 88 of 100 events and at about 64% of the test sites is reached. For wind, 99 of 100 improved events and ~84% improved sites can be obtained. This gives confidence on the potential of the introduced approach for many applications, in particular those considering wind data.

The XWS open access catalogue of extreme European windstorms from 1979 to 2012

The XWS (eXtreme WindStorms) catalogue consists of storm tracks and model-generated maximum 3 s wind-gust footprints for 50 of the most extreme winter windstorms to hit Europe in the period 1979–2012. The catalogue is intended to be a valuable resource for both academia and industries such as (re)insurance, for example allowing users to characterise extreme European storms, and validate climate and catastrophe models. Several storm severity indices were investigated to find which could best represent a list of known high-loss (severe) storms. The best-performing index was Sft, which is a combination of storm area calculated from the storm footprint and maximum 925 hPa wind speed from the storm track. All the listed severe storms are included in the catalogue, and the remaining ones were selected using Sft. A comparison of the model footprint to station observations revealed that storms were generally well represented, although for some storms the highest gusts were underestimated. Possible reasons for this underestimation include the model failing to simulate strong enough pressure gradients and not representing convective gusts. A new recalibration method was developed to estimate the true distribution of gusts at each grid point and correct for this underestimation. The recalibration model allows for storm-to-storm variation which is essential given that different storms have different degrees of model bias. The catalogue is available at www.europeanwindstorms.org.

Synthesis, Structural Characterization, and Biological Evaluation of Oxorhenium(V) Complexes with a Novel Type of Thiosemicarbazones Derived from N-[N `,N `-Dialkylamino(thiocarbonyl)]benzimidoyl Chlorides

Reactions of N-[N`,N`-diethylamino(thiocarbonyl)]benzimidoyl chloride with 4,4-dialkylthiosemicarbazides give a novel class of thiosemicarbazides/thiosemicarbazones, H(2)L, which causes a remarkable reduction of cell growth in in vitro experiments. These strong antiproliferative effects are also observed for oxorhenium(V) complexes of the general composition [ReOCl(L)], which are formed by reactions of the potentially tridentate ligands with (NBu(4))[ReOCl(4)]. A systematic substitution of the alkyl groups in the thiosemicarbazone building blocks of the ligands do not significantly influence the biological activity of the metal complexes, while the replacement of the chloro ligand by a PPh(3) ligand (by the replacement of the oxo unit by a nitrido ligand) completely terminated the cytotoxicity of the metal complexes.

Convective storm initiation in a moist tropical environment

Radar and satellite data from the Tropical Rainfall Measuring Mission-Large-Scale Biosphere-Atmosphere (TRMM-LBA) project have been examined to determine causes for convective storm initiation in the southwest Amazon region. The locations and times of storm initiation were based on the National Center for Atmospheric Research (NCAR) S-band dual-polarization Doppler radar (S-Pol). Both the radar and the Geostationary Operational Environmental Satellite-8 (GOES-8) visible data were used to identify cold pools produced by convective precipitation. These data along with high-resolution topographic data were used to determine possible convective storm triggering mechanisms. The terrain elevation varied from 100 to 600 m. Tropical forests cover the area with numerous clear-cut areas used for cattle grazing and farming. This paper presents the results from 5 February 1999. A total of 315 storms were initiated within 130 km of the S-Pol radar. This day was classified as a weak monsoon regime where convection developed in response to the diurnal cycle of solar heating. Scattered shallow cumulus during the morning developed into deep convection by early afternoon. Storm initiation began about 1100 LST and peaked around 1500-1600 LST. The causes of storm initiation were classified into four categories. The most common initiation mechanism was caused by forced lifting by a gust front (GF; 36%). Forcing by terrain (>300 m) without any other triggering mechanism accounted for 21% of the initiations and colliding GFs accounted for 16%. For the remaining 27% a triggering mechanism was not identified. Examination of all days during TRMM-LBA showed that this one detailed study day was representative of many days. A conceptual model of storm initiation and evolution is presented. The results of this study should have implications for other locations when synoptic-scale forcing mechanisms are at a minimum. These results should also have implications for very short-period forecasting techniques in any location where terrain, GFs, and colliding boundaries influence storm evolution.

Iniciação de tempestades convectivas em um ambiente tropical úmido

Pós-graduação em Agronomia (Energia na Agricultura) - FCA