764 research outputs found

    Comparing university performance by legal status: a Malmquist-type index approach for the case of the Spanish higher education system

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    This is an Accepted Manuscript of an article published by Taylor & Francis in Tertiary Education and Management on 2017, available online: http://www.tandfonline.com/10.1080/13583883.2017.1296966New public management and increasing levels of competition driven by global rankings are bringing the managerial practices of public and private higher education institutions closer together. However, these two types of institutions still maintain different objectives and traditions and enjoy different degrees of autonomy that are reflected in their internal organisational structures. We study the relative efficiency and productivity performance of private and public universities in Spain through two adaptations of the Malmquist Index. Results show that, in 2009/2010, the greater flexibility of private universities meant a better adjustment between inputs and outputs in the private sector. However, in 2013/2014, public universities had caught up with private universities. Because of the economic crisis, the inputs of public universities have decreased, but this decrease had not fully impacted their results in 2013/201

    Effects of Environmental Traits and Landscape Management on the Biodiversity of Saproxylic Beetles in Mediterranean Oak Forests

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    This study assesses the effects of environmental traits and landscape management on the biodiversity of saproxylic beetles from “dehesas” located in Sierra Morena Mountains (Córdoba, Southern Iberian Peninsula). The dehesa is an open savanna-like landscape with mature/old trees scattered on a pasture cover where both living and dead wood are of great importance for the maintenance of macroinvertebrate fauna. The study was carried out in five plots, with different environmental features and management. A total of 137 branches belonging to the four main tree species present in the area were collected, classified, and kept under four different thermal conditions. From January to June 2019, the adult emergences were followed. A total of 466 saproxylic specimens of 31 species were obtained, 5 of them included in red lists of protected fauna. Two Bostrichidae species (Lichenophanes numida Lesne and Scobicia pustulata Fab.) and two Cerambycidae (Chlorophorus ruficornis Oliv. and Trichoferus fasciculatus Faldermann) are included in the “European Red List of Saproxylic Beetles”; and the Clerid Tillus ibericus Bahillo de la Puebla, López–Colón and García–Paris, is included in the “Red Book of Invertebrate of Andalucía”. Differences were observed regarding the diversity and abundance among the plots and among the tree species from which the beetles emerged. Simple regression analyses revealed negative relationships between tree density/Buprestidae, livestock/Bostrichidae, and land use/Cerambycidae. Multivariant logistic regression analysis did not find significant relationships among environmental traits and saproxylic diversity. Results confirmed that dry wood was a main resource for the maintenance dehesas’ biodiversity because it constitutes an ecological niche exploited by a significant set of saproxylic beetles belonging to the Bostrichidae, Buprestidae, and Cerambycidae families, in addition to other guilds of species, mainly Carabidae and Cleridae, which feed on the above-mentioned groups. Our results also support that increasing environmental temperature accelerates the development of Buprestidae, but this effect was not evident for the Bostrichidae species

    Assessment and Distribution of Damages Caused by the Trunk-Boring Insects Coraebus undatus (Fabricius) (Coleoptera: Buprestidae) and Reticulitermes grassei Clément (Blattodea: Rhinotermitidae) in Mediterranean Restored Cork-Oak Forests

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    This work assesses damage caused by Coraebus undatus (Fabricius) (Coleoptera: Buprestidae) and Reticulitermes grassei Clément (Blattodea: Rhinotermitidae) in managed cork oak forests from the southern Iberian Peninsula. Lesions were diagnosed and quantified in relation to the following features: height and orientation in the trunk, diameter at breast height, solar exposure, understory presence and orography. The distribution patterns of lesions in the study area across 12 plots and in the trunk of the trees were also analyzed. The study was performed in “Sa de Hornachuelos” Natural Park (Córdoba, Spain) and the research area encompassed 12 environmentally-restored sampling plots. Data were recorded from 2007 to 2014, with yearly sampling from late June to mid-September, corresponding to the cork extraction period, since lesions caused by these insects are well distinguishable promptly after bark removal. The results reveal that C. undatus has low population levels and a non-uniform distribution pattern in the study area as well as in the trunk of the tree. It shows preference for medium height but not by any trunk orientation. R. grassei also shows low infestation levels and a preference to affect the trunk’s base. Comparatively, C. undatus showed higher infestation levels than R. grassei. The location of damage was also different, since galleries made by C. undatus predominated at intermediate trunk heights while those of R. grassei were more frequent at lower heights. Our results further showed a low co-occurrence of both species in the same tree trunks, which could be explained in terms of overlapping in the distribution areas of both species. These results provide background information that will enable natural resources managers to detect changes and trends of these species and inform future management decisions

    The cyanobacterial ribosomal-associated protein LrtA from Synechocystis sp. PCC 6803 is an oligomeric protein in solution with chameleonic sequence properties

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    The LrtA protein of Synechocystis sp. PCC 6803 intervenes in cyanobacterial post-stress survival and in stabilizing 70S ribosomal particles. It belongs to the hibernating promoting factor (HPF) family of proteins, involved in protein synthesis. In this work, we studied the conformational preferences and stability of isolated LrtA in solution. At physiological conditions, as shown by hydrodynamic techniques, LrtA was involved in a self-association equilibrium. As indicated by Nuclear Magnetic Resonance (NMR), circular dichroism (CD) and fluorescence, the protein acquired a folded, native-like conformation between pH 6.0 and 9.0. However, that conformation was not very stable, as suggested by thermal and chemical denaturations followed by CD and fluorescence. Theoretical studies of its highly-charged sequence suggest that LrtA had a Janus sequence, with a context-dependent fold. Our modelling and molecular dynamics (MD) simulations indicate that the protein adopted the same fold observed in other members of the HPF family ( - - - - - ) at its N-terminal region (residues 1–100), whereas the C terminus (residues 100–197) appeared disordered and collapsed, supporting the overall percentage of overall secondary structure obtained by CD deconvolution. Then, LrtA has a chameleonic sequence and it is the first member of the HPF family involved in a self-association equilibrium, when isolated in solution.Ministerio de Economía y Competitividad CTQ2015-64445-RMinisterio de Economía y Competitividad BIO2016-78020-RMinisterio de Economía y Competitividad FIS2014-52212-RMinisterio de Economía y Competitividad BIO2016-75634-PFundación Séneca 19353/PI/1

    Antithrombotic Treatment After Coronary Intervention: Agreement and Controversy

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    Percutaneous revascularisation has evolved dramatically in the past few decades. The approach to the management of ischaemic heart disease has changed due to the development of new devices and techniques as well as the availability of new drugs and treatment strategies. Its use in combination with antiplatelet therapies has been essential to protect against stent thrombosis. The length of time this combination therapy is used has been modified in recent years and has been the subject of extensive research. The effect of prolonging the time it is taken or shortening it has been evaluated in different clinical conditions. In practice, the decisions regarding antithrombotic therapy after percutaneous coronary intervention are informed by the patient’s profile and the characteristics of the procedures performed. In this article, we review the use of antiplatelet/anticoagulant therapy after percutaneous coronary intervention focusing on trials and guidelines addressing variable durations for combination regimens and the alternatives

    Lidar observations of large-amplitude mountain waves in the stratosphere above Tierra del Fuego, Argentina

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    Large-amplitude internal gravity waves were observed using Rayleigh lidar temperature soundings above Rio Grande, Argentina (54∘S, 68∘W), in the period 16–23 June 2018. Temperature perturbations in the upper stratosphere amounted to 80 K peak-to-peak and potential energy densities exceeded 400 J/kg. The measured amplitudes and phase alignments agree well with operational analyses and short-term forecasts of the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF), implying that these quasi-steady gravity waves resulted from the airflow across the Andes. We estimate gravity wave momentum fluxes larger than 100 mPa applying independent methods to both lidar data and IFS model data. These mountain waves deposited momentum at the inner edge of the polar night jet and led to a long-lasting deceleration of the stratospheric flow. The accumulated mountain wave drag affected the stratospheric circulation several thousand kilometers downstream. In the 2018 austral winter, mountain wave events of this magnitude contributed more than 30% of the total potential energy density, signifying their importance by perturbing the stratospheric polar vortex.Fil: Kaifler, N.. German Aerospace Center; AlemaniaFil: Kaifler, B.. German Aerospace Center; AlemaniaFil: Dörnbrack, A.. German Aerospace Center; AlemaniaFil: Rapp, M.. German Aerospace Center; AlemaniaFil: Hormaechea, José Luis. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Austral de Investigaciones Científicas; ArgentinaFil: de la Torre, Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Austral. Facultad de Ingeniería. Laboratorio de Investigación Desarrollo y Transferencia - Comisión de Investigaciones Científicas de la Provincia de Buenos Aires. Laboratorio de Investigación Desarrollo y Transferencia; Argentin

    Puntuaciones tradicionales y estimaciones TRI en tests de elección forzosa con un modelo de dominancia

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    Background: Forced-choice tests (FCTs) were proposed to minimize response biases associated with Likert format items. It remains unclear whether scores based on traditional methods for scoring FCTs are appropriate for between-subjects comparisons. Recently, Hontangas et al. (2015) explored the extent to which traditional scoring of FCTs relates to the true scores and IRT estimates. The authors found certain conditions under which traditional scores (TS) can be used with FCTs when the underlying IRT model was an unfolding model. In this study, we examine to what extent the results are preserved when the underlying process becomes a dominance model. Method: The independent variables analyzed in a simulation study are: forced-choice format, number of blocks, discrimination of items, polarity of items, variability of intra-block diffi culty, range of diffi culty, and correlation between dimensions. Results: A similar pattern of results was observed for both models; however, correlations between TS and true thetas are higher and the differences between TS and IRT estimates are less discrepant when a dominance model involved. Conclusions: A dominance model produces a linear relationship between TS and true scores, and the subjects with extreme thetas are better measuredAntecedentes: los tests de elección forzosa (TEFs) fueron propuestos para reducir los sesgos de respuesta de ítems tipo Likert. Se cuestiona que los métodos de puntuación tradicional (PT) empleados permitan hacer comparaciones entre-sujetos. Recientemente, Hontangas et al. (2015) exploraron cómo las PTs obtenidas con diferentes TEFs se relacionan con sus puntuaciones verdaderas y estimaciones TRI, mostrando las condiciones para ser utilizadas cuando el modelo subyacente es un modelo de unfolding. El objetivo del trabajo actual es comprobar si el patrón de resultados se mantiene con un modelo de dominancia. Método: las variables independientes del estudio de simulación fueron: formato de elección forzosa, número de bloques, discriminación de los ítems, polaridad de los ítems, variabilidad de la dificultad intrabloque, rango de difi cultad del test y correlación entre dimensiones. Resultados: un patrón similar de resultados fue obtenido en ambos modelos, pero en el modelo de dominancia las correlaciones entre PTs y puntuaciones verdaderas son más altas y las diferencias entre PTs y estimaciones TRI se reducen. Conclusiones: un modelo de dominancia produce una relación lineal entre PTs y puntuaciones verdaderas, y los sujetos con puntuaciones extremas son medidos mejorThe research has been funded by the Ministry of Economy and Competitivity of Spain, project PSI2012-3334

    Parasitics Impact on the Performance of Rectifier Circuits in Sensing RF Energy Harvesting

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    This work presents some accurate guidelines for the design of rectifier circuits in radiofrequency (RF) energy harvesting. New light is shed on the design process, paying special attention to the nonlinearity of the circuits and the modeling of the parasitic elements. Two different configurations are tested: a Cockcroft–Walton multiplier and a half-wave rectifier. Several combinations of diodes, capacitors, inductors and loads were studied. Furthermore, the parasitics that are part of the circuits were modeled. Thus, the most harmful parasitics were identified and studied in depth in order to improve the conversion e ciency and enhance the performance of self-sustaining sensing systems. The experimental results show that the parasitics associated with the diode package and the via holes in the PCB (Printed Circuit Board) can leave the circuits inoperative. As an example, the rectifier e ciency is below 5% without considering the influence of the parasitics. On the other hand, it increases to over 30% in both circuits after considering them, twice the value of typical passive rectifiers.This work was supported in part by the Spanish Research and Development National Program under projects TIN2016-75097-P, TEC2017-85529-C3-1-R and RTI2018-102002-A-I00
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