1,931 research outputs found

    La contratación pública de obras: situación actual y puntos de mejora

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    La construcción pública ha sido, es y será uno de los pilares fundamentales del sector construcción español, si bien la actual situación de crisis económica y la reducción de la inversión pública en nuevas infraestructuras ha generado un descenso de actividad hasta niveles similares a los años noventa. El retorno a índices de actividad más elevados no solo se conseguirá con la recuperación de la economía del país, sino que será necesario realizar ciertas mejoras en los procesos de licitación con objeto de conseguir una mayor funcionalidad y flexibilidad en la contratación pública de obras

    Acquisition of Demonstratives in English and Spanish

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    The present work re-evaluates the long-standing claim that demonstratives are among infants’ earliest and most common words. Although demonstratives are deictic words important for joint attention, deictic gestures and non-word vocalizations could serve this function in early language development; the role of demonstratives may have been overestimated. Using extensive data from the CHILDES corpora (Study 1, N = 66, 265 transcripts) and McArthur-Bates CDI database (Study 2, N = 950), the language production of 18- to 24-month-old Spanish- and English-speaking children was analyzed to determine the age and order of acquisition, and frequency of demonstratives. Results indicate that demonstratives do not typically appear before the 50th word and only become frequent from the two-word utterance stage. Corpus data show few differences between Spanish and English, whereas parental report data suggest much later acquisition for demonstratives in English. These findings expand our knowledge of the foundations of deictic communication, and of the methodological challenges of assessing early production of function words

    Assessing children’s empathy through a Spanish adaptation of the Basic Empathy Scale: parent’s and child’s report forms

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    The aim of the current research was to study cognitive and affective empathy in children aged 6–12 years old, and their associations with children’s family environment and social adjustment. For this purpose, we developed the Spanish version of the Basic Empathy Scale (BES), self- and parent-report forms. Factorial analyses confirmed a two-component model of empathy in both self- and parent-report forms. Concordance between parent–child measures of empathy was low for cognitive and affective factors. Analyses of variance on the cognitive and affective components brought a significant effect of age for self-reported cognitive empathy, with older children scoring higher than younger ones. Gender brought out a significant principal effect for self-reported affective empathy, with girls scoring higher than boys. No other main effects were found for age and gender for the rest of the factors analyzed. Children’s empathy was associated with socioeconomic status and other family socialization processes, as well as children’ social behaviors. Overall the new measures provided a coherent view of empathy in middle childhood and early adolescence when measured through self and parent reports, and illustrate the similarity of the validity of the BES in a European-Spanish culture

    Estudio del efecto de abducción del pulgar en una prótesis de mano de bajo coste: una propuesta de Benchmark

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    Comunicació presentada a la IX Reunión del Capítulo Español de la Sociedad Europea de Biomecánica (ESB 2019)La irrupción en el ámbito doméstico de la tecnología de impresión en 3D por deposición fundida (FDM) ha permitido mejorar los diseños de prótesis de mano bajo coste (BC) que intentan cubrir las necesidades más básicas con el mínimo tiempo y coste (normalmente menos de 450€1,2), bajo la premisa de "hágalo usted mismo" (DIY). Hoy en día, muchos diseños de manos de BC pueden descargarse libremente como un archivo de estereolitografía (.stl) desde distintos repositorios de diseño (instructables.com, thingiverse.com) o, más explícitamente, desde iniciativas sin ánimo de lucro como e-NABLE3, Open Hand Project1 y Openbionics4. La experiencia de uso con estos diseños sigue poniendo de manifiesto la necesidad de estandarizar las pruebas para caracterizar y comparar la mecánica de todas las tipologías de prótesis de mano de BC. El presente trabajo compara la funcionalidad y la actuación mecánica de dos variantes del modelo de una prótesis de mano de bajo coste. En el proceso, se proponen diferentes técnicas y se evalúa su interés para formar parte de un benchmark

    Receptor Binding Domain (RBD) Structural Susceptibility in the SARS-CoV-2 Virus Spike Protein Exposed to a Pulsed Electric Field

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    SARS-CoV-2 is responsible for causing the Coronavirus disease 2019 (COVID-19) pandemic, which has so far infected more than thirty million people and caused almost a million deaths. For this reason, it has been a priority to stop the transmission of the outbreak through preventive measures, such as surface disinfection, and to establish bases for the design of an effective disinfection technique without chemical components. In this study, we performed in silico analysis to identify the conformational alterations of the SARS-CoV-2 Spike Receptor Binding Domain (RBD) caused by the effect of a pulsed electric field at two different intensities. We found that both stimuli, especially the one with the highest angular frequency and amplitude, modified the electrical charge distribution in the RBD surface and the number of hydrogen bonds. Moreover, the secondary structure was significantly affected, with a decrease of the structured regions, particularly the regions with residues involved in recognizing and interacting with the receptor ACE2. Since many regions suffered conformational changes, we calculated RMSF and ΔRMSF to identify the regions and residues with larger fluctuations and higher flexibility. We found that regions conformed by 353-372, 453-464, and 470-490 amino acid residues fluctuate the most, where the first is considered a therapeutic target, and the last has alreadybeen characterized for its flexibility. Our results indicate that a pulsed electric field can cause loss of stability in the Spike-RBD, and we were able to identify the vulnerable sites to be used as a starting point for the development of viral inhibition or inactivation mechanisms

    Brain activity changes with emotional words in different stages of psychosis

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    BackgroundTo date, a large number of functional magnetic resonance imaging (fMRI) studies have been conducted on psychosis. However, little is known about changes in brain functioning in psychotic patients using an emotional auditory paradigm at different stages of the disease. Such knowledge is important for advancing our understanding of the disorder and thus creating more targeted interventions. This study aimed to investigate whether individuals with first-episode psychosis (FEP) and chronic schizophrenia show abnormal brain responses to emotional auditory processing and to compare the responses between FEP and chronic schizophrenia. MethodsPatients with FEP (n = 31) or chronic schizophrenia (n = 23) and healthy controls (HCs, n = 31) underwent an fMRI scan while presented with both emotional and nonemotional words. ResultsUsing HC as a reference, patients with FEP showed decreased right temporal activation, while patients with chronic schizophrenia showed increased bilateral temporal activation. When comparing the patient groups, individuals with FEP showed lower frontal lobe activation. ConclusionTo the best of our knowledge, this is the first study with an emotional auditory paradigm used in psychotic patients at different stages of the disease. Our results suggested that the temporal lobe might be a key issue in the physiopathology of psychosis, although abnormal activation could also be derived from a connectivity problem. There is lower activation in the early stage and evolution to greater activation when patients become chronic. This study highlights the relevance of using emotional paradigms to better understand brain activation at different stages of psychosis

    Developing strategies to reduce spray drift in pneumatic spraying in vineyards: Assessment of the parameters affecting droplet size in pneumatic spraying

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    Pneumatic sprayers are widely used in vineyards due to their very fine droplet size, which makes the drift risk to become an important problem to be considered. The aim of this study was to assess the effect of the spout diameter at the release point on the spray droplet size and uniformity achieved for different liquid flow rates (LFR) and air flow rates (AFR).A test bench was developed to simulate a real pneumatic sprayer under laboratory conditions, and it was empirically adjusted to match the air pressure conditions as closely as possible to real working conditions. Two positions of insertion of the liquid hose, the conventional position (CP) and an alternative position (AP), were tested for three LFRs, 1.00, 1.64, and 2.67Lmin-1, and four AFRs, 0.280, 0.312, 0.345, and 0.376m3 s-1. The air speed decrease between the two insertion points of the liquid hose was measured. A Malvern SprayTec® instrument was used to measure the droplet size, and the D50, D10, and D90 parameter values were obtained. The relative SPAN factor (RSF) was also calculated. A model to predict variations in D50 was fitted using the aforementioned parameters.The results show that variations in the diameter of the spout significantly change the droplet size, producing a mean increase of 59.45% in D50 and similar increases in D10 and D90. The model developed to predict variations in D50 has a very high degree of accuracy (R2 =0.945). The relative decrease in the air speed along the spout did not present significant differences for the different airflow rates tested. The results of the study show that the droplet size produced in pneumatic spraying can be modified easily by varying the air spout dimensions. This should be taken into account by manufacturers from a design point of view.Postprint (author's final draft

    Can solid body destruction explain abundance discrepancies in planetary nebulae?

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    In planetary nebulae, abundances of oxygen and other heavy elements derived from optical recombination lines are systematically higher than those derived from collisionally excited lines. We investigate the hypothesis that the destruction of solid bodies may produce pockets of cool, high-metallicity gas that could explain these abundance discrepancies. Under the assumption of maximally efficient radiative ablation, we derive two fundamental constraints that the solid bodies must satisfy in order that their evaporation during the planetary nebula phase should generate a high enough gas phase metallicity. A local constraint implies that the bodies must be larger than tens of meters, while a global constraint implies that the total mass of the solid body reservoir must exceed a few hundredths of a solar mass. This mass greatly exceeds the mass of any population of comets or large debris particles expected to be found orbiting evolved low- to intermediate-mass stars. We therefore conclude that contemporaneous solid body destruction cannot explain the observed abundance discrepancies in planetary nebulae. However, similar arguments applied to the sublimation of solid bodies during the preceding asymptotic giant branch (AGB) phase do not lead to such a clear-cut conclusion. In this case, the required reservoir of volatile solids is only one ten-thousandth of a solar mass, which is comparable to the most massive debris disks observed around solar-type stars, implying that this mechanism may contribute to abundance discrepancies in at least some planetary nebulae, so long as mixing of the high metallicity gas is inefficient.Comment: 8 pages, no figures, ApJ in pres
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