1000 resultados para Roca blanda


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Se describe la estructura y el patrón espacial de un ecotono bosque subalpino-pastos alpinos dominado por Pinus uncinata Ram. (Pirineos Orientales, Cerdanya, Estanys de la Pera). La historia de perturbaciones de la zona sugiere que el patrón espacial del ecotono puede haber sido afectado recientemente por el pastoreo. Se situó una parcela rectangular (30 x 100 m) cruzando el ecotono con su lado mayor paralelo a la pendiente. Para cada individuo de P. uncinata dentro de la parcela se midió: su localización (coordenadas x, y), y diversas variables estructurales (diámetros basal y a 1,3 m de altura, altura, radios de las copas, número de cohortes de acículas, edad estimada -número de internodos del tronco). Los individuos vivos de P. uncinata se clasificaron según su tamaño (adultos, jóvenes, vástagos y plántulas) y forma de crecimiento (krummholz -individuos arbustivos policórmicos-). Se describieron cuantitativamente el tipo de sustrato (roca, materia orgánica, suelo) y la cobertura de herbáceas, arbustos y P. uncinata usando transectos paralelos a la pendiente. La estructura del ecotono se describió mediante: (i) los análisis del patrón de puntos (K de Ripley, casos uni- y bivariante) y (ii) del patrón de superficies (correlogramas omni- y unidireccionales de Moran). El ecotono estudiado mostró una distribución de individuos de P. uncinata en agregados, predominando los vástagos. Los análisis espaciales mostraron la existencia y el tamaño de agregados con valores similares para ciertas variables de los árboles situados dentro del bosque (p. ej. 8-10 m para la edad estimada). La edad estimada de los individuos jóvenes (60 años <) estaba positivamente correlacionada con la altura y el diámetro basal. La regeneración reciente presentó dos máximos (1965-67, 1973-77). Apareció una posible cohorte de individuos más viejos (1941-57). A partir de 1975, la regeneración declinó de forma exponencial. El establecimiento...

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La Comunitat Europea ha decidit realitzar una base de dades per controlar la despesa pública parlamentària, tant dels parlaments com dels seus parlamentaris, i que les dades puguin ser consultades on line. L'objectiu del present treball és realitzar la base de dades on es guardarà la informació indicada pel client, així com un seguit de consultes i dades estadístiques que es podran consultar a través d'una plana web.

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Polymorphous Si is a nanostructured form of hydrogenated amorphous Si that contains a small fraction of Si nanocrystals or clusters. Its thermally induced transformations such as relaxation, dehydrogenation, and crystallization have been studied by calorimetry and evolved gas analysis as a complementary technique. The observed behavior has been compared to that of conventional hydrogenated amorphous Si and amorphous Si nanoparticles. In the temperature range of our experiments (650700 C), crystallization takes place at almost the same temperature in polymorphous and in amorphous Si. In contrast, dehydrogenation processes reflect the presence of different hydrogen states. The calorimetry and evolved gas analysis thermograms clearly show that polymorphous Si shares hydrogen states of both amorphous Si and Si nanoparticles. Finally, the total energy of the main SiH group present in polymorphous Si has been quantified

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A partir del análisis metrológico realizado en 4 asentamientos ibéricos del tramo final del Ebro, en la región ilercavona planteamos la utilización de una unidad de medida basada en un pie de 0,32 m. Su primera aplicación probable se identifica en la torre bipartita del Castellot de la Roca Roja de Benifallet (final del siglo v a.C.), pero será entre los siglos iii y ii a.C. cuando tendrá una mayor adaptación, como se puede apreciar en su uso en la trama urbana de El Castellet de Banyoles de Tivissa, el sistema defensivo de Sant Miquel de Vinebre y probablemente en el edificio singular del Perengil de Vinaròs. Su mayor difusión durante el siglo iii a.C. se relaciona con el momento de concentración de poblamiento en el territorio ilercavón en grandes núcleos, como El Castellet de Banyoles, dentro de un fenómeno de jerarquización del territorio que muestra un sistema económico centralizado de tipo protoestatal.

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We hypothesized that platelet-activating factor (PAF), a potent inflammatory mediator, could induce gas exchange abnormalities in normal humans. To this end, the effect of aerosolized PAF (2 mg/ml solution; 24 micrograms) on ventilation-perfusion (VA/Q) relationships, hemodynamics, and resistance of the respiratory system was studied in 14 healthy, nonatopic, and nonsmoking individuals (23 +/- 1 [SEM]yr) before and at 2, 4, 6, 8, 15, and 45 min after inhalation, and compared to that of inhaled lyso-PAF in 10 other healthy individuals (24 +/- 2 yr). PAF induced, compared to lyso-PAF, immediate leukopenia (P < 0.001) followed by a rebound leukocytosis (P < 0.002), increased minute ventilation (P < 0.05) and resistance of the respiratory system (P < 0.01), and decreased systemic arterial pressure (P < 0.05). Similarly, compared to lyso-PAF, PaO2 showed a trend to fall (by 12.2 +/- 4.3 mmHg, mean +/- SEM maximum change from baseline), and arterial-alveolar O2 gradient increased (by 16.7 +/- 4.3 mmHg) (P < 0.02) after PAF, because of VA/Q mismatch: the dispersion of pulmonary blood flow and that of ventilation increased by 0.45 +/- 0.1 (P < 0.01) and 0.29 +/- 0.1 (P < 0.04), respectively. We conclude that in normal subjects, inhaled PAF results in considerable immediate VA/Q inequality and gas exchange impairment. These results reinforce the notion that PAF may play a major role as a mediator of inflammation in the human lung.

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Cell motility is an essential process that depends on a coherent, cross-linked actin cytoskeleton that physically coordinates the actions of numerous structural and signaling molecules. The actin cross-linking protein, filamin (Fln), has been implicated in the support of three-dimensional cortical actin networks capable of both maintaining cellular integrity and withstanding large forces. Although numerous studies have examined cells lacking one of the multiple Fln isoforms, compensatory mechanisms can mask novel phenotypes only observable by further Fln depletion. Indeed, shRNA-mediated knockdown of FlnA in FlnB¿/¿ mouse embryonic fibroblasts (MEFs) causes a novel endoplasmic spreading deficiency as detected by endoplasmic reticulum markers. Microtubule (MT) extension rates are also decreased but not by peripheral actin flow, because this is also decreased in the Fln-depleted system. Additionally, Fln-depleted MEFs exhibit decreased adhesion stability that appears in increased ruffling of the cell edge, reduced adhesion size, transient traction forces, and decreased stress fibers. FlnA¿/¿ MEFs, but not FlnB¿/¿ MEFs, also show a moderate defect in endoplasm spreading, characterized by initial extension followed by abrupt retractions and stress fiber fracture. FlnA localizes to actin linkages surrounding the endoplasm, adhesions, and stress fibers. Thus we suggest that Flns have a major role in the maintenance of actin-based mechanical linkages that enable endoplasmic spreading and MT extension as well as sustained traction forces and mature focal adhesions.

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We hypothesized that platelet-activating factor (PAF), a potent inflammatory mediator, could induce gas exchange abnormalities in normal humans. To this end, the effect of aerosolized PAF (2 mg/ml solution; 24 micrograms) on ventilation-perfusion (VA/Q) relationships, hemodynamics, and resistance of the respiratory system was studied in 14 healthy, nonatopic, and nonsmoking individuals (23 +/- 1 [SEM]yr) before and at 2, 4, 6, 8, 15, and 45 min after inhalation, and compared to that of inhaled lyso-PAF in 10 other healthy individuals (24 +/- 2 yr). PAF induced, compared to lyso-PAF, immediate leukopenia (P < 0.001) followed by a rebound leukocytosis (P < 0.002), increased minute ventilation (P < 0.05) and resistance of the respiratory system (P < 0.01), and decreased systemic arterial pressure (P < 0.05). Similarly, compared to lyso-PAF, PaO2 showed a trend to fall (by 12.2 +/- 4.3 mmHg, mean +/- SEM maximum change from baseline), and arterial-alveolar O2 gradient increased (by 16.7 +/- 4.3 mmHg) (P < 0.02) after PAF, because of VA/Q mismatch: the dispersion of pulmonary blood flow and that of ventilation increased by 0.45 +/- 0.1 (P < 0.01) and 0.29 +/- 0.1 (P < 0.04), respectively. We conclude that in normal subjects, inhaled PAF results in considerable immediate VA/Q inequality and gas exchange impairment. These results reinforce the notion that PAF may play a major role as a mediator of inflammation in the human lung.

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Information and telecommunication technologies are called to play a major role in the changes that healthcare systems have to face to cope with chronic disease. This paper reports a telemedicine experience for the home care of chronic patients suffering from chronic obstructive pulmonary disease (COPD) and an integrated system designed to carry out this experience. To determine the impact on health, the chronic care telemedicine system was used during one year (2002) with 157 COPD patients in a clinical experiment; endpoints were readmissions and mortality. Patients in the intervention group were followed up at their homes and could contact the care team at any time through the call center. The care team shared a unique electronic chronic patient record (ECPR) accessible through the web-based patient management module or the home visit units. Results suggest that integrated home telemedicine services can support health professionals caring for patients with chronic disease, and improve their health.We have found that simple telemedicine services (ubiquitous access to ECPR, ECPR shared by care team, accessibility to case manager, problem reporting integrated in ECPR) can increase the number of patients that were not readmitted (51% intervention, 33% control), are acceptable to professionals, and involve low installation and exploitation costs. Further research is needed to determine the role of telemonitoring and televisit services for this kind of patients.

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Erythropoietin (rHuEPO) has proven to be effective in the treatment of anemia of chronic renal failure (CRF). Despite improving the quality of life, peak oxygen uptake after rHuEPO therapy is not improved as much as the increase in hemoglobin concentration ([Hb)] would predict. We hypothesized that this discrepancy is due to failure of O2 transport rates to rise in a manner proportional to [Hb]. To test this, eight patients with CRF undergoing regular hemodialysis were studied pre- and post-rHuEPO ([Hb] = 7.5 +/- 1.0 vs. 12.5 +/- 1.0 g x dl-1) using a standard incremental cycle exercise protocol. A group of 12 healthy sedentary subjects of similar age and anthropometric characteristics served as controls. Arterial and femoral venous blood gas data were obtained and coupled with simultaneous measurements of femoral venous blood flow (Qleg) by thermodilution to obtain O2 delivery and oxygen uptake (VO2). Despite a 68% increase in [Hb], peak VO2 increased by only 33%. This could be explained largely by reduced peak leg blood flow, limiting the gain in O2 delivery to 37%. At peak VO2, after rHuEPO, O2 supply limitation of maximal VO2 was found to occur, permitting the calculation of a value for muscle O2 conductance from capillary to mitochondria (DO2). While DO2 was slightly improved after rHuEPO, it was only 67% of that of sedentary control subjects. This kept maximal oxygen extraction at only 70%. Two important conclusions can be reached from this study. First, the increase in [Hb] produced by rHuEPO is accompanied by a significant reduction in peak blood flow to exercising muscle, which limits the gain in oxygen transport. Second, even after restoration of [Hb], O2 conductance from the muscle capillary to the mitochondria remains considerably below normal.

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The objective of this study was to revise the nominal, and only described, species of the genera Allomachilis Silvestri, 1906, from Australia, and Kuschelochilis Wygodzinsky, 1951, from Chile (Microcoryphia: Meinertellidae). The studied specimens came from the collections deposited in the: American Museum of Natural History (USA); Instituto di Entomologia Agraria dell'Università di Portici (Italy); South Australian Museum (Australia); Carmen Bach collection of the Universidad Autónoma de Barcelona (Spain); and the entomology collection of the Instituto de Investigação Científica Tropical (Portugal). The revision of the nominal species of the genera Allomachilis and Kuschelochilis allows to consider the Neotropical genus a junior synonym of the Australian one.

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L'objectiu de l'article és contribuir a la reflexió actual sobre les competències genèriques en l'educació superior. Es va desenvolupar una investigació sobre l'adquisició de competències genèriques en els programes de ciències socials de llicenciatura (Psicologia) de Blanquerna-Universitat Ramon Llull. Per a aquests estudis s’ha estat desenvolupant una metodologia innovadora anomenada Seminari. El seu propòsit se centra, entre altres qüestions, en el desenvolupament de competències genèriques. En primer lloc, les competències genèriques són avaluades respecte si són o no són percebudes com a importants per part dels estudiants d'últim curs, i respecte quin és el context principal per la seva adquisició. La metodologia de Seminari, que es caracteritza en aquest estudi, correlaciona més estretament amb la percepció de la importància de les competències en el món professional que els altres contextos, fins i tot les assignatures o l’adquisició de competències fora de la universitat. La investigació té com a objectiu el contribuir a aconseguir una millor comprensió dels millors contextos per a l'adquisició de competències genèriques en l'educació superior i de la importància d’aquestes en el món professional. Es desenvolupa implícitament una metodologia per a l'estudi de l'adquisició de competències i per a la caracterització d'un model educatiu centrat en competències.

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Although metabolic syndrome (MS) and systemic lupus erythematosus (SLE) are often associated, a common link has not been identified. Using the BWF1 mouse, which develops MS and SLE, we sought a molecular connection to explain the prevalence of these two diseases in the same individuals. We determined SLE- markers (plasma anti-ds-DNA antibodies, splenic regulatory T cells (Tregs) and cytokines, proteinuria and renal histology) and MS-markers (plasma glucose, non-esterified fatty acids, triglycerides, insulin and leptin, liver triglycerides, visceral adipose tissue, liver and adipose tissue expression of 86 insulin signaling-related genes) in 8-, 16-, 24-, and 36-week old BWF1 and control New-Zealand-White female mice. Up to week 16, BWF1 mice showed MS-markers (hyperleptinemia, hyperinsulinemia, fatty liver and visceral adipose tissue) that disappeared at week 36, when plasma anti-dsDNA antibodies, lupus nephritis and a pro-autoimmune cytokine profile were detected. BWF1 mice had hyperleptinemia and high splenic Tregs till week 16, thereby pointing to leptin resistance, as confirmed by the lack of increased liver P-Tyr-STAT-3. Hyperinsulinemia was associated with a down-regulation of insulin related-genes only in adipose tissue, whereas expression of liver mammalian target of rapamicyn (mTOR) was increased. Although leptin resistance presented early in BWF1 mice can slow-down the progression of autoimmunity, our results suggest that sustained insulin stimulation of organs, such as liver and probably kidneys, facilitates the over-expression and activity of mTOR and the development of SLE.

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This issue of the Catalan Journal of Linguistics was conceived with the idea to promote comparative studies of the languages spoken in the Iberian Peninsula. The importance of comparison in linguistics dates back to neogrammarians in the xix century due to their interest of discovering the common roots of most of the languages spoken in Europe. In order to get to that objective, comparison of phonological patterns were crucial to retrieve the common Indo-European origins

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El objetivo del presente artículo es demostrar la viabilidad económica de Cataluña como Estado independiente, analizando en particular los aspectos comerciales y hacendísticos. Los datos demuestran que Cataluña tiene un nivel de PIB per cápita por encima de la media UE-15, y a pesar de ser un país de pequeña dimensión cuenta con una economía muy abierta que le permite obtener efectos de escala en el crecimiento y ser un país competitivo. Asimismo, en términos hacendísticos, se estima que una Cataluña independiente tendría una ganancia fiscal de alrededor del 7% del PIB, lo que le permitiría no sólo mantener el actual Estado del Bienestar sino incluso incrementarlo.