Estudi experimental d’una reixa de Central Hidràulica

L’estudi d’una reixa de central hidràulica s’ha enfocat en una aplicació concreta de l’anàlisi vibracional. L’anàlisi vibracional de tota estructura és important per tal de determinar la resposta dinàmica davant excitacions externes, i evitar així situacions de ressonància que poden escurçar substancialment la vida útil de la reixa degut per la fatiga. Hi ha dos maneres de fer l’estudi comentat, per una banda tenim l’estudi mitjançant simulació i per l’altra existeix l’anàlisi experimental. En aquest cas s’ha escollit la vessant experimental per tal de donar solucions al tipus de incidències esmentades. La necessitat de tractament de dades experimentals ha provocat que s’hagi desenvolupat un programa matemàtic amb MATLAB versió 7.10.0. Aquesta aplicació s’ha utilitzat per poder realitzar de manera automatitzada tota la part matemàtica que l’anàlisi de freqüències pròpies porta implícita al darrera. En aquest projecte es realitza l’anàlisi vibracional d’una reixa de central hidroelèctrica amb problemes de fissures per fatiga. Per tant, es realitzen les proves experimentals suficients per detectar les freqüències pròpies i problemàtiques de la reixa en mal estat. Finalment es compara amb un altre anàlisi experimental que la correcció feta a la reixa, millora el comportament d’aquesta davant de les fonts excitadores que pugui tenir. A part de l’estudi de la reixa en aire per determinar les freqüències pròpies, també s’ha pres mesures menys amb menys sensors (per la disponibilitat d’elements de captació específics), de la reixa dins de l’aigua. L’objectiu és detectar les primeres freqüències pròpies i fer un anàlisis dels transitoris. La reixa d’estudi està ubicada dins d’una canonada que evoca a la turbina, subjecta per unes rodes a l’estructura cilíndrica. La reixa esta constituïda per una sèrie de platines, barres fines verticals, i per tallamars, panells horitzontals de major rigidesa. Després d’analitzar les freqüències pròpies de la reixa malmesa es constata el risc de coincidència entre aquestes i les freqüències excitadores realitzada per despreniments de vòrtex alternatius generats quan és travessada per l’aigua a velocitats elevades. Es comprova que els modes de vibració que presenten estan en el mateix pla que el despreniment. Es presenta un paquet de mesures per tal de augmentar les freqüències pròpies de l’estructura i així evitar una possible ressonància amb les freqüències excitadores. En problemàtiques com les esmentades, la solució més destacada passa per fer l’estructura més rígida. Finalment el segon estudi demostra que la reixa té les freqüències pròpies en rangs més elevats i que l’esmorteïment d’aquestes freqüències és molt més gran

LA ESTRUCTURA DE DEPENDENCIA DEL PRECIO DE LAS ACCIONES EN LA IDENTIFICACIÓN DE GRUPOS ESTRATÉGICOS: APLICACION AL SECTOR BANCARIO ESPAÑOL

The aim of this paper is to identify strategic groups in a sector using security pricesas a starting point. The initial assumption is that the co-movement of certain common stocksprice residuals, once the effects of the market and industry have been removed from thereturns, show the existence of shared economic dimensions and common responses to certainspecific phenomena which are inherent when firms belong to the same strategic group. Themethodology that has been used has two basic stages. In the first one we use financia1 theorymulti-index models in order to obtain the residual returns, and in the second stage statisticalclustering techniques are used to find subclasses of firms with residuals behaving in a similarway through time. As a result, three strategic groups are identified in the Spanish bankingindustry, and the relative instability in the structure of groups is proved for the periodconsidered. El objetivo de este trabajo consiste en identificar grupos estratégicos en una industriaa partir de las cotizaciones bursátiles. La hipótesis de partida es que el comovimiento de los residuos de ciertas acciones, una vez eliminados en la rentabilidad los efectos del mercado y de la industria, delataría la existencia de dimensiones económicas compartidas y de respuestas comunes a ciertos fenómenos no sistemáticos que caracterizarían la pertenencia de determinadas empresas a un mismo grupo estratégico. La metodología utilizada consta básicamente de dos etapas. En la primera se utilizan los modelos factoriales de la teoría financiera en orden a obtener los residuos, y en la segunda se emplean técnicas estadísticas de agrupamiento para encontrar conjuntos de empresas cuyos residuos tienden a comportarse de forma similar a lo largo del tiempo. Como resultado de la aplicación de esta metodología al sector bancario español se identifican tres grupos estratégicos, y se prueba la relativa inestabilidad de la estratificación intraindustrial estimada en el período considerado.

Geophysical survey of two rural sites in Mallorca (Balearic Islands, Spain): unveiling Roman villae

Two rural sites on the island of Mallorca (Balearic Islands, Spain) have been investigated with geophysical methods. A previous archaeological field survey provided surface ceramics that allowed for a first classification of the sites as possible Roman rural settlements, possibly villae. The objective of the investigation was to work towards the identification of architectural remains to better understand the nature of the sites. Using the 7-probe fluxgate gradiometer array LEA MAX, magnetic measurements were executed on a large area on each site. GPR measurements were subsequently carried out to examine selected areas of interest in detail by means of the IDS GPR system based on the Fast-Wave module. The investigated areas demonstrated excellent surface conditions with a negligible number of sources of disturbance, permitting a detailed interpretation of the geophysical data. The results helped to reveal the presence of architectural remains beneath the soil at both sites

The Power of Wild Plants in Feeding Humanity: A Meta-Analytic Ethnobotanical Approach in the Catalan Linguistic Area

Wild food plants (WFP) have always been present in our kitchen, although they have not always been given the same importance as crops. In the Catalan linguistic area (CLA), covered in this paper, WFP were of great importance as a subsistence food not only during the years of the Spanish civil war (1936-1939) and World War II (1939-1945), but also long before these periods and in the years thereafter. The CLA has been well studied at the level of traditional knowledge on plant biodiversity, and much of this information is collected in a database by the EtnoBioFiC research group. The aim of this work is to carry out a meta-analysis of the WFP dataset of the CLA (only regarding edible uses, drinks excluded) and to identify the most quoted plants, and the information associated with them. With data from 1659 informants, we recorded 10,078 use reports of 291 taxa (278 of which at specific or subspecific levels and 13 only determined at generic level) belonging to 67 families. The most reported taxa, also with highest cultural importance indexes, are Thymus vulgaris, Foeniculum vulgare subsp. piperitum, Laurus nobilis, Rubus ulmifolius and Mentha spicata. The ethnobotanicity index for food plants is 6.62% and the informant consensus factor, also for food uses, is a very high 0.97, supporting the robustness of the information. The results provided and discussed in this work concern a significant part of the edible resources in the territory considered, which is, often and mainly, underestimated and underutilised. Its consideration could be an opportunity to promote closer and more sustainable agriculture. From the state-of-the-art of this question, it is possible to propose old, in some cases forgotten foods that could be newly introduced onto the market, first, but not only, at a local level, which could be interesting for new crop development in the frame of a valorisation of territorial identity. Keywords: Catalan countries; Catalan linguistic area; edible plants; ethnobotany; traditional knowledge; wild food plant

Synthesis of 0D to 3D hybrid-carbon nanomaterials carrying platinum(0) nanoparticles : towards the electrocatalytic determination of methylparabens at ultra-trace levels

A generic synthetic methodology has been applied for functionalizing four conducting carbon nanoallotropes, such as 0D carbon nanohorns (CNHs), 1D carbon nanotubes (CNTs), 2D reduced graphene oxide (rGO) and 3D graphite (GP) with platinum(0) nanoparticles (Pt-NP), and exploited towards the electrocatalytic determination of methylparaben (MeP), which has been classified as a potential endocrine-disrupting chemical. After an accurate physical, electrochemical and electroanalytical characterization, the hybrid Pt-NP@CNTs yields detection limits at nM levels, rather than the μM levels obtained with the rest of carbon homologous because of the optimum carbon/nanoparticle composition ratio. The proposed electrochemical sensing system has also been successfully validated by comparison with the standard bench-top chromatographic tool (HPLC), demonstrating its feasibility for MeP quantification in real cosmetic samples at ultra-trace levels. According to the outstanding performance of the hybrid Pt-NP@CNTs electrochemical platform, it can be regarded as a potential alternative to the conventional HPLC technique for the development of rapid, straightforward, cost-effective, reproducible and highly sensitive electrochemical sensors to be exploited in pharmacological, biomedical and environmental field

Participació política i social activa dels joves de 15 - 16 anys

La participació activa, que és un dret fonamental que té la ciutadania, esdevé un factor clau en el desenvolupament comunitari responsable dels adolescents. És necessari incentivar la participació dels adolescents mitjançant òrgans de participació municipal que els permetin opinar i decidir sobre aquells aspectes que els impliquen. D'acord amb la proposta del Consell d'Infants de Tonucci (1996) aquest article científic ofereix una base teòrica per la possible creació d'un òrgan de participació municipal per adolescents de 15 i 16 anys a Castellar del Vallès.La participación activa, que es un derecho fundamental que tienen los ciudadanos, supone un factor clave en el desarrollo comunitario responsable de los adolescentes. Es necesario incentivar la participación de los adolescentes mediante órganos de participación municipal que les permitan opinar y decidir sobre los aspectos que los implican. De acuerdo con la propuesta del Consejo de Niños de Tonucci (1996) este artículo científico ofrece una base teórica para la posible creación de un órgano de participación municipal para adolescentes de 15 y 16 años en Castellar del Vallès.Active participation, which is a fundamental right of the citizens, becomes a key factor in responsible community development of young people. It is necessary to encourage the participation on a local participatory body, which enables young people to be part of decision making processes about issues affecting their lifes. According to the proposal of the Children's Council by Tonucci (1996) this scientific article provides a theoretical basis for the future creation of a local participation body from 15 to 16 years old in Castellar del Vallès

Organocatalytic vs. Ru-based electrochemical hydrogenation of nitrobenzene in competition with the hydrogen evolution reaction

The electrochemical reduction of organic contaminants allows their removal from water. In this contribution, the electrocatalytic hydrogenation of nitrobenzene is studied using both oxidized carbon fibres and ruthenium nanoparticles supported on unmodified carbon fibres as catalysts. The two systems produce azoxynitrobenzene as the main product, while aniline is only observed in minor quantities. Although PhNO2 hydrogenation is the favoured reaction, the hydrogen evolution reaction (HER) competes in both systems under catalytic conditions. H2 formation occurs in larger amounts when using the Ru nanoparticle based catalyst. While similar reaction outputs were observed for both catalytic systems, DFT calculations revealed some significant differences related to distinct interactions between the catalytic material and the organic substrates or products, which could pave the way for the design of new catalytic materials

Discriminació de gènere en el mercat laboral a Catalunya. La paradoxa de l'emprenedoria, política de conciliació o normalització

El següent treball de recerca es fonamenta sobre un doble objectiu: En primer lloc, busca comprendre, fins a quin punt, les polítiques de gènere s'incorporen en el disseny de les estratègies i programes multi-nivell enfocats a l'emprenedoria femenina; revisant diversos documents oficials. Per altra banda, se n'estudia l'impacte sobre dones emprenedores en un context local. S'observarà que la concreció de les estratègies impulsades en l'àmbit regional i local no inclouran la perspectiva de gènere, tot i atendre les necessitats mercantils del col·lectiu, únicament. L'impacte de gènere serà condicional, tenint una incidència baixa o nul·la sobre les trajectòries laborals observades

Intravascular hemolysis triggers NAFLD characterized by a deregulation of lipid metabolism and lipophagy blockade

Intravascular hemolysis is a common feature of different clinical entities, including sickle cell disease and malaria. Chronic hemolytic disorders are associated with hepatic damage; however, it is unknown whether heme disturbs lipid metabolism and promotes liver steatosis, thereby favoring the progression to nonalcoholic fatty liver disease (NAFLD). Using an experimental model of acute intravascular hemolysis, we report here the presence of liver injury in association with microvesicular lipid droplet deposition. Hemolysis promoted serum hyperlipidemia and altered intrahepatic triglyceride fatty acid composition, with increments in oleic, palmitoleic, and palmitic acids. These findings were related to augmented expression of transporters involved in fatty acid uptake (CD36 and MSR1) and deregulation of LDL transport, as demonstrated by decreased levels of LDL receptor and increased PCSK9 expression. Hemolysis also upregulated hepatic enzymes associated with cholesterol biosynthesis (SREBP2, HMGC1, LCAT, SOAT1) and transcription factors regulating lipid metabolism (SREBP1). Increased LC3II/LC3I ratio and p62/SQSTM1 protein levels were reported in mice with intravascular hemolysis and hepatocytes stimulated with heme, indicating a blockade of lipophagy. In cultured hepatocytes, cell pretreatment with the autophagy inductor rapamycin diminished heme-mediated toxicity and accumulation of lipid droplets. In conclusion, intravascular hemolysis enhances liver damage by exacerbating lipid accumulation and blocking the lipophagy pathway, thereby promoting NAFLD. These new findings have a high translational potential as a novel NAFLD-promoting mechanism in individuals suffering from severe hemolysis episodes. © 2023 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland

Non-structural carbohydrate dynamics associated with drought-induced die-off in woody species of a shrubland community

The relationship between plant carbon economy and drought responses of co-occurring woody species can be assessed by comparing carbohydrate (C) dynamics following drought and rain periods, relating these dynamics to species' functional traits. We studied nine woody species coexisting in a continental Mediterranean shrubland that experienced severe drought effects followed by rain. During drought, NSC concentrations were overall lower in stems and roots of plants experiencing leaf loss, while SS decreases were smaller. Roots had higher NSC concentrations than stems. After the rain, NSC concentrations continued to decrease, while SS increased. Green foliage recovered after rain, particularly in plants previously experiencing higher leaf loss, independently of NSC concentrations during drought. Species with lower WD tended to have more SS during drought and lower SS increases after rain. In low-WD species, plants with severe leaf loss had lower NSC relative to undefoliated ones. No significant relationship was found between H or SLA and C content or dynamics. Our community-level study reveals that, while responses were species-specific, C stocks overall diminished in plants affected by prolonged drought and did not increase after a pulse of seasonal rain. Dynamics were faster for SS than NSC. We found limited depletion of SS, consistent with their role in basal metabolic, transport and signalling functions. In a scenario of increased drought under climate change, NSC stocks in woody plants are expected to decrease differentially in coexisting species, with potential implications for their adaptive abilities and community dynamics