1,060 research outputs found

    Developing a novel approach to analyse the regimes of temporary streams and their controls on aquatic biota

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    Temporary streams are those water courses that undergo the recurrent cessation of flow or the complete drying of their channel. The biological communities in temporary stream reaches are strongly dependent on the temporal changes of the aquatic habitats determined by the hydrological conditions. The use of the aquatic fauna structural and functional characteristics to assess the ecological quality of a temporary stream reach can not therefore be made without taking into account the controls imposed by the hydrological regime. This paper develops some methods for analysing temporary streams' aquatic regimes, based on the definition of six aquatic states that summarize the sets of mesohabitats occurring on a given reach at a particular moment, depending on the hydrological conditions: flood, riffles, connected, pools, dry and arid. We used the water discharge records from gauging stations or simulations using rainfall-runoff models to infer the temporal patterns of occurrence of these states using the developed aquatic states frequency graph. The visual analysis of this graph is complemented by the development of two metrics based on the permanence of flow and the seasonal predictability of zero flow periods. Finally, a classification of the aquatic regimes of temporary streams in terms of their influence over the development of aquatic life is put forward, defining Permanent, Temporary-pools, Temporary-dry and Episodic regime types. All these methods were tested with data from eight temporary streams around the Mediterranean from MIRAGE project and its application was a precondition to assess the ecological quality of these streams using the current methods prescribed in the European Water Framework Directive for macroinvertebrate communities

    Imagen ecográfica de la obstrucción biliar extrahepática en el perro : descripción de 7 casos

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    Se realizó un estudio ecográfico en siete perros que presentaban un cuadro de ictericia por obstrucción biliar extrahepática. Esta técnica permitió llegar al diagnóstico en seis de los casos. Se estudió la imagen ecográfica de la dilatación de las vías biliares intra y extrahepáticas, así como los signos asociados, tales como la presencia de una masa en el área pancreática, que pudiesen orientar sobre el origen de la obstrucción.An ultrasonographic examination was carried in out 7 dogs with icterus due to an extrahepatic biliary obstruction. This technique allowed the diagnosis in 6 of the dogs. The sonographic appearance of the dilated intra and extrahepatic biliary tree was assessed, as well as the associated lesions, such as the presence of a mass in the pancreatic area, which could guide towards the origin of the obstruction

    Progression of Doppler changes in early-onset small for gestational age fetuses. How frequent are the different progression sequences?

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    OBJECTIVE: To evaluate the progression of Doppler abnormalities in early-onset fetal smallness (SGA). METHODS: A total of 948 Doppler examinations of the umbilical artery (UA), middle cerebral artery (MCA) and ductus venosus (DV), belonging to 405 early-onset SGA fetuses, were studied, evaluating the sequences of Doppler progression, the interval examination-labor at which Doppler became abnormal and the cumulative sum of Doppler anomalies in relation with labor proximity. RESULTS: The most frequent sequences were that in which only the UA pulsatility index (PI) became abnormal (42.1%) and that in which an abnormal UA PI appeared first, followed by an abnormal MCA PI (24.2%). In general, 71.3% of the fetuses followed the classical progression sequence UA→MCA→DV, mostly in the early stages of growth restriction (84.1%). In addition, the UA PI was the first parameter to be affected (9 weeks before delivery), followed by the MCA PI and the DV PIV (1 and 0 weeks). Finally, the UA PI began to sum anomalies 5 weeks before delivery, while the MCA and DV did it at 3 and 1 weeks before the pregnancy ended. CONCLUSIONS: In early-onset SGA fetuses, Doppler progression tends to follow a predictable order, with sequential changes in the umbilical, cerebral and DV impedances

    Quality Management practices, absorptive capacity and innovation performance

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    Quality Management practices (QMP) are a potentially useful tool for increasing a company’s innovation performance. However, the empirical evidence regarding the impact of QMP on innovation performance has been mixed. The purpose of this study is to extend understanding of the impact of QMP on innovation performance by investigating the mediating effect of absorptive capacity on this relationship. A proposed research model and hypotheses are tested using cross-sectional survey data from a sample of 230 leading Spanish firms. The results indicate that QMP enable the development of absorptive capacity, contributing to innovation performance

    Persistent Currents in Small, Imperfect Hubbard Rings

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    We have done a study with small, imperfect Hubbard rings with exact diagonalization. The results for few-electron rings show, that the imperfection, whether localized or not, nearly always decrease, but can also \emph{increase} the persistent current, depending on the character of the imperfection and the on-site interaction. The calculations are generally in agreement with more specialized studies. In most cases the electron spin plays an important role.Comment: 6 pages, 4 figure

    GSK-3β orchestrates the inhibitory innervation of adult-born dentate granule cells in vivo

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    Adult hippocampal neurogenesis enhances brain plasticity and contributes to the cognitive reserve during aging. Adult hippocampal neurogenesis is impaired in neurological disorders, yet the molecular mechanisms regulating the maturation and synaptic integration of new neurons have not been fully elucidated. GABA is a master regulator of adult and developmental neurogenesis. Here we engineered a novel retrovirus encoding the fusion protein Gephyrin:GFP to longitudinally study the formation and maturation of inhibitory synapses during adult hippocampal neurogenesis in vivo. Our data reveal the early assembly of inhibitory postsynaptic densities at 1 week of cell age. Glycogen synthase kinase 3 Beta (GSK-3β) emerges as a key regulator of inhibitory synapse formation and maturation during adult hippocampal neurogenesis. GSK-3β-overexpressing newborn neurons show an increased number and altered size of Gephyrin+ postsynaptic clusters, enhanced miniature inhibitory postsynaptic currents, shorter and distanced axon initial segments, reduced synaptic output at the CA3 and CA2 hippocampal regions, and impaired pattern separation. Moreover, GSK-3β overexpression triggers a depletion of Parvalbumin+ interneuron perineuronal nets. These alterations might be relevant in the context of neurological diseases in which the activity of GSK-3β is dysregulatedPID2020-113007RB-I00, SAF-2017-82185-R, PID2020-112824GB-10

    Audience participation as added value for public service proximity television. The case study of ETB 2’s La noche de…”

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    While the model of public service television that focuses on audiences has been traditionally criticised for being more akin to the commercial television model than to the public service broadcasting model, contemporary literature points out that in the age of digitisation and convergence audience participation is precisely a key element of public television (Castro, 2012; Doyle, 2010; Kjus, 2009; Bardoel, 2007). This article examines audience participation in Spanish regional public service television and, particularly, tries to determine two questions: 1) whether the variety of participation channels provided by crossmedia productions –a TV show’s website, discussion forums and Twitter and Facebook accounts– increases effective audience participation; and 2) whether this participation can be said to contribute to the fulfilment of the mission of public service television, especially proximity television. Method. The study first provides a review of the literature on audience participation and the forms of participation promoted by European, national and regional policies. The TV show La noche de…, broadcast by the Spanish network ETB 2, is subsequently analysed based on the results of the literature review. Results: The increasing attention paid to audience participation in the European and Spanish literature and legislations is not proportionally reflected on the reality of public service television, and particularly of regional public service television corporations

    GaAs nanoscale membranes: prospects for seamless integration of III–Vs on silicon

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    The growth of compound semiconductors on silicon has been widely sought after for decades, but reliable methods for defect-free combination of these materials have remained elusive. Recently, interconnected GaAs nanoscale membranes have been used as templates for the scalable integration of nanowire networks on III-V substrates. Here, we demonstrate how GaAs nanoscale membranes can be seamlessly integrated on silicon by controlling the density of nuclei in the initial stages of growth. We also correlate the absence or presence of defects with the existence of a single or multiple nucleation regime for the single membranes. Certain defects exhibit well-differentiated spectroscopic features that we identify with cathodoluminescence and micro-photoluminescence techniques. Overall, this work presents a new approach for the seamless integration of compound semiconductors on silicon

    Segunda parte de Avisos con algunas deuociones particulares [Texto impreso]

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    Hay un ejemplar encuadernado con: Avisos de padre y rosario de nuestra Señora (XVII/1256)Sign.: A-E8Frontispicio grab. xil.Capitales xil.Grab. xil. de la Inmaculada Concepción en p. 5
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