83 research outputs found

    Estudio comparativo de dos tipologías estructurales para soporte de antenas de telefonía móvil

    Get PDF
    Este proyecto intenta evaluar dos tipos de estructuras para el diseño de una torre de telefonía móvil. Para ello, en primer lugar se ha hecho una revisión bibliográfica para conocer todo lo relacionado al tipo de estructura que se desea diseñar y a las solicitaciones particulares que tienen las mismas en el ámbito de la telefonía móvil, en España. Se ha escogido el programa ED-Tridim para modelizar el comportamiento de las estructuras, por lo que ha sido necesario familiarizarse con dicho código computacional. Se han hecho las consideraciones específicas del diseño y se ha procedido al desarrollo y análisis de las estructuras en el programa EDTridim. Se han extraído los resultados numéricos y se han analizado y comparado. Finalmente se han puntualizado las conclusiones sobre el estudio realizado y se han sugerido algunas líneas de trabajo futuro para enriquecerlo.Ingeniería Técnica en Mecánic

    At the Crossroads. Management and Business History in Entrepreneurship Research

    Get PDF
    Recent calls for a historic turn in organization studies offer the opportunity to relaunch dialogue between management and business history research. Focusing on the specific domain of entrepreneurship research, this article illustrates the potential of mutual contributions from management and business history. In doing so, it demonstrates how historical approaches strongly influenced the early theoretical developments within entrepreneurship and demonstrates the potential to contribute to future scholarly debates. In sum, this article brings closer together business history and management studies stressing that their different perspectives and approaches are very valuable to enriching entrepreneurship research

    At the crossroads. Management and business history in entrepreneurship research

    Get PDF
    Recent calls for a historic turn in organization studies offer the opportunity to relaunch dialogue between management and business history research. Focusing on the specific domain of entrepreneurship research, this article illustrates the potential of mutual contributions from management and business history. In doing so, it highlights how historical approaches strongly influenced the early theoretical developments within entrepreneurship and demonstrates the potential to contribute to future scholarly debates. In sum, this article brings closer together business history and management studies stressing that their different perspectives and approaches are very valuable to enriching entrepreneurship research

    Nomadism and movement as epistemologies of the contemporary world

    Get PDF
    De la misma manera que el movimiento y el nomadismo, en tanto que formas de vida opuestas al sedentarismo, implican no solo el abandono de la idea de un hogar fijo sino también un desafío activo o una evitación furtiva de la autoridad sedentaria del estado, el movimiento y el nomadismo como epistemologías confrontan el orden generalmente fijo de los lenguajes, discursos y perspectivas con los que la ciencia intenta explicar nuestro mundo social. Emergen así nuevos caminos para pensar el movimiento, las subjetividades, lo grupal y lo institucional, en un mundo que no solo es global, sino real y virtual al mismo tiempo. En este número extraordinario, se reúnen aportaciones que experimentan, discuten y reflexionan cuestionando el pensamiento estático.In the same way that movement and nomadism as a lifestyles opposite to sedentism involve not only the abandonment of the idea of a permanent home, but also an active challenge or furtive avoidance of the state's sedentary authority, movement and nomadism as epistemologies confront the generally fixed order of languages, discourses and perspectives with which science tries to explain our social world. New ways of thinking about movement, subjectivities, groups and institutions emerge, in a world that is not only global, but real and virtual at the same time. In this special issue we have gathered the contributions that experiment and questioning static thinking

    New Data on Orthotrichum gigantosporum Lewinsky (Orthotrichaceae, Bryophyta), a Widespread Northern Andean-Patagonian Endemic Moss

    Full text link
    The moss family Orthotrichaceae is still poorly known in the southern extreme of South America. This is especially true regarding the morphological variability, geographical distribution, and ecological affinities of the species restricted to the Andean-Patagonian area. These deficiencies are addressed for Orthotrichum gigantosporum Lewinsky, one of the least known and most interesting endemics of the area. After examining the rich collections made by our team in southern Chile and Argentina, we have found numerous new localities for the species. Orthotrichum gigantosporum has proven to be a widespread moss in the forests and scrublands of the northern sector of the Andean-Patagonian area. In the light of new morphological data, an updated description of the species is presented and the characteristics that allow its differentiation are discussed and illustrated. The ecological data obtained on the populations also help to characterise the distribution of this moss in relation to various environmental factors. An updated list of the accepted species of Orthotrichaceae present in the Andean-Patagonian area is also provided, facilitating an estimate of endemicity rates within each genu

    Hydrophobic-electrostatic balance driving the LCST offset aggregation-redissolution behavior of N-alkylacrylamide-based ionic terpolymers

    Get PDF
    A series of random terpolymers composed of N-isopropylacrylamide (NIPAAm), 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS), and N-tert-butylacrylamide (NTBAAm) monomers were synthesized by free radical polymerization. The molar fraction of the negatively charged monomer (AMPS) was maintained constant (0.05) for all studied terpolymer compositions. Turbidity measurements were used to evaluate the influence of the relative amount of NIPAAm and NTBAAm, polymer concentration, and solution ionic strength on the cloud point and redissolution temperatures (macroscopic phase separation). Dynamic light scattering (DLS) was employed to elucidate some aspects regarding the molecular scale mechanism of the temperature-induced phase separation and to determine the low critical solution temperature (LCST). The aqueous solutions of terpolymers remained clear at all studied temperatures; turbidity was only observed in the presence of NaCl. The cloud point temperature (CPT) determined by turbidimetry was found to be systematically much higher than the LCST determined by DLS; nanosized aggregates were observed at temperatures between the LCST and the CPT. Both CPT and LCST decreased when increasing the molar ratio of NTBAAm (increased hydrophobicity). It was found that above a critical molar fraction of NTBAAm (0.25-0.30) the aggregation rate suddenly decreased. Polymers with NTBAAm content lower than 0.25 showed a fast macroscopic phase separation, but the formed large aggregates are disaggregating during the cooling ramp at temperatures still higher than the LCST. On the contrary, polymers withNTBAAmcontents above 0.30 showed a slow macroscopic phase separation, and the formed large aggregates only redissolved when LCST was reached. These differences were explained on the basis of a delicate balance between the electrostatic repulsion and the hydrophobic attractive forces, which contribute cooperatively to the formation of metastable nanosized aggregates.The authors acknowledge funding from EU Marie Curie Actions, Alea Jacta Est (MEST-CT-2004-008104), and Portuguese Foundation For Science and Technology (FCT) (SFRH/BPD/34545/2007). This work was carried out under the scope of the European NoE EXPERTISSUES (NMP3-CT-2004-500283)

    Regular Consumption of Cocoa and Red Berries as a Strategy to Improve Cardiovascular Biomarkers via Modulation of Microbiota Metabolism in Healthy Aging Adults

    Get PDF
    The aim of the present study was to analyze the effects of cocoa flavanols and red berry anthocyanins on cardiovascular biomarkers, such as homocysteine, angiotensin-converting enzyme (ACE), nitric oxide (NO), flow-mediated vasodilation (FMD), blood pressure and lipid profile. Additionally, we aimed to ascertain their possible interactions with microbiota related metabolites, such as secondary bile acids (SBA), short-chain fatty acids (SCFA) and trimethylamine N-oxide (TMAO). A randomized, parallel-group study, single-blind for the research team, was performed on 60 healthy volunteers between the ages of 45 and 85, who consumed 2.5 g/day of cocoa powder (9.59 mg/day of total flavanols), 5 g/day of a red berry mixture (13.9 mg/day of total anthocyanins) or 7.5 g/day of a combination of both for 12 weeks. The group that had consumed cocoa showed a significant reduction in TMAO (p = 0.03) and uric acid (p = 0.01) levels in serum, accompanied by an increase in FMD values (p = 0.03) and total polyphenols. corrected by creatinine (p = 0.03) after the intervention. These latter values negatively correlated with the TMAO concentration (R = −0.57, p = 0.02). Additionally, we observed an increase in carbohydrate fermentation in the groups that had consumed cocoa (p = 0.04) and red berries (p = 0.04) between the beginning and the end of the intervention. This increase in carbohydrate fermentation was correlated with lower levels of TC/HDL ratio (p = 0.01), systolic (p = 0.01) and diastolic blood pressure (p = 0.01). In conclusion, our study showed a positive modulation of microbiota metabolism after a regular intake of cocoa flavanols and red berry anthocyanins that led to an improvement in cardiovascular function, especially in the group that consumed cocoa

    Poliquistosis renal autosómica dominante: ¿quiénes se benefician del tratamiento con tolvaptán?

    Get PDF
    La poliquistosis renal autosómica dominante es la enfermedad renal hereditaria más frecuente. Se caracteriza por la progresiva aparición de quistes renales que suelen conducir a la enfermedad renal crónica extrema en la edad adulta. La aprobación del uso de tolvaptán (antagonista del receptor V2 de la vasopresina) ha marcado un cambio significativo en el tratamiento de esta enfermedad. En los últimos años apareció evidencia que demuestra el beneficio en iniciar tratamiento con tolvaptán en pacientes que presentan una enfermedad con rápida evolución. Se realiza una revisión descriptiva de los principales estudios clínicos publicados en el periodo 2012-2022 y se sugiere un esquema de utilidad para seleccionar aquellos pacientes que pueden beneficierse del inicio de tratamiento
    corecore