987 resultados para elikagaien zientzia eta teknologia


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La organización de un evento resulta paradigmática en el proceso de construcción de imágenes territoriales vividas in situ. La fabricación de imágenes territoriales - turísticas o no- con motivo de la organización de un evento para su posterior consolidación en el imaginario colectivo de los asistentes, plantea una curiosa alternativa de promoción turística implícita en la propia estrategia de gestión del evento. En efecto, no cabe duda de que el evento, por sí mismo, representa una importante estrategia de promoción del territorio, pero hay más; también puede devenir a modo de catalizador de imágenes, de creador de imaginarios capaces de fijar una marca de ciudad en su conjunto. El presente artículo dará a conocer las posibilidades que se desprenden de la organización de un evento en relación al posicionamiento identitario y promocional de un territorio.

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The net mechanical efficiency of positive work (eta(pos)) has been shown to increase if it is immediately preceded by negative work. This phenomenon is explained by the storage of elastic energy during the negative phase and its release during the subsequent positive phase. If a transition time (T) takes place, the elastic energy is dissipated into heat. The aim of the present study was to investigate the relationship between eta(pos) and T, and to determine the minimal T required so that eta(pos) reached its minimal value. Seven healthy male subjects were tested during four series of lowering-raising of the body mass. In the first series (S (0)), the negative and positive phases were executed without any transition time. In the three other series, T was varied by a timer (0.12, 0.24 and 0.56 s for series S (1), S (2) and S (3), respectively). These exercises were performed on a force platform sensitive to vertical forces to measure the mechanical work and a gas analyser was used to determine the energy expenditure. The results indicated that eta(pos) was the highest (31.1%) for the series without any transition time (S (0)). The efficiencies observed with transition times (S (1), S (2) and S (3)) were 27.7, 26.0 and 23.8%, respectively, demonstrating that T plays an important role for mechanical efficiency. The investigation of the relationship between eta(pos) and T revealed that the minimal T required so that eta(pos) reached its minimal value is 0.59 s.

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Aquestes jornades espanyoles de documentació tenen lloc cada dos anys en una localitat diferent d'Espanya, i són organitzades conjuntament per FESABID (Federación Española de Sociedades de Archivística, Biblioteconomía, Documentación y Museística) i l'associació professional de la comunitat autònoma on se celebren. En aquesta ocasió, Bilbao fou la ciutat amfitriona, i ALDEE (Artxibozain, Liburuzain eta Dokumentazainen Euskal Elkartea), una de les associacions professionals que existeixen al País Basc, participà en l'organització

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We investigated the rheological properties of living human airway smooth muscle cells in culture and monitored the changes in rheological properties induced by exogenous stimuli. We oscillated small magnetic microbeads bound specifically to integrin receptors and computed the storage modulus (G') and loss modulus (G") from the applied torque and the resulting rotational motion of the beads as determined from their remanent magnetic field. Under baseline conditions, G' increased weakly with frequency, whereas G" was independent of the frequency. The cell was predominantly elastic, with the ratio of G" to G' (defined as eta) being ~0.35 at all frequencies. G' and G" increased together after contractile activation and decreased together after deactivation, whereas eta remained unaltered in each case. Thus elastic and dissipative stresses were coupled during changes in contractile activation. G' and G" decreased with disruption of the actin fibers by cytochalasin D, but eta increased. These results imply that the mechanisms for frictional energy loss and elastic energy storage in the living cell are coupled and reside within the cytoskeleton.

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OBJECTIVES: To evaluate the role of endothelin-1 (ET-1) in hypertension, we investigated density and distribution of ETA and ETB receptors in hearts and kidneys of deoxycorticosterone acetate (DOCA)-salt and 1 kidney -- 1 clip (1K1C) hypertensive rats. METHODS: Five groups of uninephrectomized Wistar rats were put on a low salt diet. Three groups of rats drank tap water and two groups received saline. One group of each regimen received DOCA subcutaneously and two corresponding groups without DOCA served as controls. The fifth group of rats had the renal artery clipped to induce 1K1C hypertension. At 6 weeks, mean arterial pressure (MAP) was recorded and membrane binding assays using 125I-ET-1 were carried out. RESULTS: MAP was increased from control 122 +/- 3 to 155 +/- 6 and 218 +/- 11 mmHg in DOCA-salt and 1K1C rats, respectively, and cardiac weight index was increased. ETA receptors were predominantly expressed in the heart, whereas ETB receptors were predominant in the kidney. In the kidneys, the density of the ETB receptor subtype was upregulated in DOCA-salt and 1K1C rats from 160 +/- 8 to 217 +/- 12 and 190 +/- 2 fmol/mg (P < 0.05), respectively, and ETA tended to be downregulated (P = 0.057). Plasma renin activity was decreased in DOCA-salt rats from 17 +/- 3 to 0.17 +/- 0.01 ng/ml per h and increased in 1K1C rats on low salt diet to 30 +/- 5 ng/ml per h. CONCLUSIONS: Since ETB is the predominant endothelin receptor in the kidneys, upregulation of the ETB receptor mediating vasodilation and downregulation of the ETA receptor mediating vasoconstriction would be compatible with a mainly renal counter-regulatory effect of endothelin-1 to hypertension. Both low and high renin models of hypertension may be affected.

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UCRET = User's Cognitive Resources Evoking Technology

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Posteriormente a la publicación de mi primera contribución a la flora algológica de nuestras aguas dulces (1944), he dado preferencia a la preparación de trabajos de carácter local y ecológico, por entender que éstos podían conducir más rápidamente al planteamiento, y quizá a la resolución, de problemas de interés superior al puramente taxonómico. Pero el estudio de muchos centenares de muestras de algas, procedentes de localidades dispersas de Cataluña y de comarcas limítrofes, ha ido prosiguiendo independientemente, permitiendo reunir una cantidad considerable de datos inéditos. Eáta nota es la primera de una serie de contribuciones taxonómicas a nuestra flora algológica, que tendrán como base el material no utilizado en otros trabajos de limnología regional o local.