651 research outputs found
Huellas de Pterosaurios en el grupo Oncala (Soria, España). Pteraichnus palaciei-saenzi, nov. icnosp.
Several ptesoraur tracksites have been found in the northern area of Soria, Spain, among which Barranco de Valdelavilla (Valdelavilla) stands out due to the great amount of tracks, and Los Tormos (Santa Cruz de Yanguas) because of the occurrence of trackways. This group of tracks is attributable to the ichnogenus Pteraichnus, and the existence of a new ichnospecies has been verified (Pteraichnus palaciei-saenzi). To this moment, only sporadic tracks from these flying reptiles have been found in the other localities and this poor fossil trackway record cannot be attributed to a specific ichnospecies. These findings together with the trackway found in Los Tormos (Santa Cruz de Yanguas), described by Moratalla (1993) and Lockley et al. (1995), and digit impressions of these animals found at Río Ventosa and Valdehuérteles (Fuentes y Meijide, 1996) confirm the generalized presence of these animals in the Oncala Formation, more specifically at subunits IV-b of the Huérteles Aloformation and at the base of V-b of the Valdeprado Aloformation. This can be explained on the basis of environmental conditions in this area at that time -a muddy plain covered at one point by lakes with a more or less long life- being appropriate for these reptiles, who are always associated to coastal or aquatic terrestrial environments, to live and develop.En la zona Norte de Soria se han descubierto numerosos yacimientos de huellas de pterosaurios, destacando el del Barranco de Valdelavilla (Valdelavilla) por la cuantía de las mismas y el de Los Tormos (Santa Cruz de Yanguas) por la presencia de rastros. El conjunto de huellas pertenece al icnogénero Pteraichnus, habiéndose constatado la presencia de una nueva icnoespecie (Pteraichnus palaciei-saenzi). En el resto de las localidades sólo se han encontrado, por ahora, esporádicas huellas de estos reptiles voladores, no permitiendo la escasez del registro icnológico la asignación a una icnoespecie concreta. Estos hallazgos, junto con el rastro ubicado también en los Tormos (Santa Cruz de Yanguas), descrito por Moratalla (1993) y Lockley et al. (1995), y la localización de falanges de estos animales en Río Ventosa y Valdehuérteles (Fuentes y Meijide, 1996), confirman la presencia generalizada de estos animales en el Grupo Oncala y más concretamente en las subunidades IV-b de la Aloformación Huérteles y en la base de la V-b de la Aloformación Valdeprado. Tal circunstancia se puede explicar sobre la base de la existencia, en aquellos tiempos, de unas condiciones medioambientales propicias para la vida y el desarrollo de estos reptiles, asociadas siempre con ambientes litorales o terrestres acuáticos, como es el que presentaba esta zona (llanura fangosa, cubierta, en algunos momentos, por lagos de vida más o menos larga)
Equations for the Correlation and Prediction of Partition Coefcients of Neutral Molecules and Ionic Species in the Water-Isopropanol Solvent System
We use literature data on solubilities of 46 compounds in the water-isopropanol (IPA) system to obtain the corresponding partition coefficients, P, for transfer from water to water- IPA mixtures. We have then used our previously constructed linear free energy equation to obtain equations that correlate log10 P at water-IPA intervals across the entire water-IPA system. These equations can then be used to predict partition coefficients and solubilities of further compounds in the water-IPA systems at 298 K. The coefficients in our linear free energy equation encode information on the physicochemical properties of the water- IPA mixtures. We show that the hydrogen bond basicity of the water-IPA mixtures only increases slightly from water to IPA, but that the hydrogen bond acidity of the mixtures decreases markedly from water to IPA in a smooth continuous manner. We have also used data on ions and on ionic species to set out equations for the estimation of their partition coefficients from water to water-IPA mixtures. We find that for partition from water to IPA itself, log10 P = − 1.81 for H+
Leakage isolation using pressure sensitivity analysis in water distribution networks: Application to the Barcelona case study
Leaks are present to some extent in all water-distribution systems. This paper proposes a leakage
localisation method based on the pressure measurements and pressure sensitivity analysis of nodes in a
network. The sensitivity analysis using analytical tools is not a trivial job in a real network because the
huge non-explicit non-línear systems of equation that describe its dynamics. Simulations of the network in
presence and absence of leakage may provide an approximation of this sensitivity. This matrix is binarised
using a threshold independent of the node. The binary matrix is assumed as a signature matrix for
leakages. However, there is a trade-off between the resolution of the leakage isolation procedure and the
number of available pressure sensors. In order to maximise the isolability with a reasonable number of
sensors, an optimal sensor placement methodology, based on genetic algorithms, is also proposed. This
methodology has been developed for Barcelona Network using Piccolo simulator. The sensor placement
and the leakage detection and localization methodologies are applied to district management areas (DMA).Peer ReviewedPostprint (published version
AB0690 Antiphospholipid antibodies and spondyloarthritis. Truth or myth? Our results in a third level hospital
[EN] The importance of antiphospholipid antibodies and their clinical
involvement in thrombotic phenomena, isolated or associated with certain autoimmune
diseases such as systemic lupus erythematosus, is known. However, in
spondyloarthritis (SpA) there is little published data about it.S
Blockchain Architecture Based on Decentralised PoW Algorithm
Blockchain has gained increasing popularity across various industries due to its decentralized, stable, and secure nature. Consensus algorithms play a crucial role in maintaining the security and efficiency of Blockchain systems and selecting the right algorithm can lead to significant performance improvements. This article aims to provide a comparative review of the most used Blockchain consensus algorithms, highlighting their strengths and weaknesses. Additionally, we propose a dissociated architecture for an efficient Blockchain system that doesn't compromise on security. A comparison is made between this architecture and the reviewed algorithms, considering aspects such as algorithm performance, energy consumption, mining, decentralization level, and vulnerability to security threats. The research findings demonstrate that the proposed architecture can support complex algorithms with high security while addressing issues related to efficiency, processing performance, and energy consumption
Understanding the importance of animation in human-computer interfaces and its relation to user experience
Animation is increasingly used in multimedia user interfaces (UI). Ever more applications are including animation to improve their UI and user experience (UX). Animation seems to play a key role to develop user-friendly, easy-to-use and easy-to-understand apps that achieve a satisfactory UX. This work attempts to explain animation performance in multimedia UI and how this affects the UX. We found that: (1) animation is a key element of multimedia UI that strongly affects UX and can improve it, if applied correctly; (2) animation enhances: reduced perceived waiting time, explanatory and cognitive support, efficient feedback and increased user attention; (3) animation's major properties lie in adapting its intensity, function, time and aesthetics to the context of action. Additionally, we identified two categories of animation aspects in multimedia UI: internal aspects and external features. Furthermore, this study demonstrates that the design of animated multimedia interfaces does not have a standardised methodology. Animation is incorporated ad-hoc, under the individual empirical experience of the creators, and without any a priori guarantee of usefulness or success. Therefore, our future work aims to generate an integral model where the variables related to animation in multimedia UI that modulate UX are analysed, and thus improve human-computer interfaces
Propiedades psicométricas de la versión española de la escala Mindful Attention Awareness Scale (MAAS)
La Mindful Attention Awareness Scale (MAAS) es una escala sencilla y de rápida administración que evalúa, de forma global, la capacidad disposicional de un individuo de estar atento y consciente de la experiencia del momento presente en la vida cotidiana. La escala es un autoinfome unifactorial de 15 ítems con visión del constructo mindfulness centrada en la variable atención/consciencia. El instrumento puede ser utilizado en sujetos con o sin experiencia en meditación y es ampliamente utilizado en investigación. Con el objetivo de establecer las propiedades psicométricas de la MAAS, se administró a un total de 385 sujetos, 201 pertenecientes a una muestra clínica y 184 a una muestra control de estudiantes universitarios. Los análisis psicométricos de la versión española de la MAAS muestran buenas propiedades, tanto en términos de validez como de fiabilidad. El instrumento presentó una buena validez convergente con la Five Facets Mindfulness Questionnaire (FFMQ) así como discriminante respecto a la clínica depresiva. Así mismo obtuvo unos buenos índices de fiabilidad (α de Cronbach de 0,89), una buena estabilidad temporal y replica la estructura unifactorial original que agrupa el 42,8% de la varianza total. Los resultados obtenidos resultan congruentes con los estudios realizados con la versión en inglés del instrumento. La MAAS es un instrumento de simple y rápida administración que nos permite evaluar la capacidad general de mindfulness de un individuo y que puede ser utilizado tanto en la investigación clínica como en sujetos sanos
Fullerene-based molecular nanobridges: A first-principles study
Building upon traditional quantum chemistry calculations, we have implemented
an {\em ab-initio} method to study the electrical transport in nanocontacts. We
illustrate our technique calculating the conductance of C molecules
connected in various ways to Al electrodes characterized at the atomic level.
Central to a correct estimate of the electrical current is a precise knowledge
of the local charge transfer between molecule and metal which, in turn,
guarantees the correct positioning of the Fermi level with respect to the
molecular orbitals. Contrary to our expectations, ballistic transport seems to
occur in this system.Comment: 4 pages in two-column forma
Outcomes of Frail Patients While Waiting for Kidney Transplantation : Differences between Physical Frailty Phenotype and FRAIL Scale
Frailty is associated with poorer outcomes among patients waiting for kidney transplantation (KT). Several different tools to measure frailty have been used; however, their predictive value is unknown. This is a prospective longitudinal study of 449 KT candidates evaluated for frailty by the Physical Frailty Phenotype (PFP) and the FRAIL scale. During the study period, 296 patients received a KT, while 153 remained listed. Patients who did not get receive a transplant were more frequently frail according to PFP (16.3 vs. 7.4%, p = 0.013). Robust patients had fewer hospital admissions during the 1st year after listing (20.8% if PFP = 0 vs. 43.4% if ≥1, and 27.1% if FRAIL = 0 vs. 48.9% if ≥1) and fewer cardiovascular events (than FRAIL ≥ 1) or major infectious events (than PFP ≥ 1). According to PFP, scoring 1 point had an impact on patient survival and chance of transplantation in the univariate analysis. The multivariable analysis corroborated the result, as candidates with PFP ≥ 3 had less likelihood of transplantation (HR 0.45 [0.26-0.77]). The FRAIL scale did not associate with any of these outcomes. In KT candidates, pre-frailty and frailty according to both the PFP and the FRAIL scale were associated with poorer results while listed. The PFP detected that frail patients were less likely to receive a KT, while the FRAIL scale did not
A first-principles approach to electrical transport in atomic-scale nanostructures
We present a first-principles numerical implementation of Landauer formalism
for electrical transport in nanostructures characterized down to the atomic
level. The novelty and interest of our method lies essentially on two facts.
First of all, it makes use of the versatile Gaussian98 code, which is widely
used within the quantum chemistry community. Secondly, it incorporates the
semi-infinite electrodes in a very generic and efficient way by means of Bethe
lattices. We name this method the Gaussian Embedded Cluster Method (GECM). In
order to make contact with other proposed implementations, we illustrate our
technique by calculating the conductance in some well-studied systems such as
metallic (Al and Au) nanocontacts and C-atom chains connected to metallic (Al
and Au) electrodes. In the case of Al nanocontacts the conductance turns out to
be quite dependent on the detailed atomic arrangement. On the contrary, the
conductance in Au nanocontacts presents quite universal features. In the case
of C chains, where the self-consistency guarantees the local charge transfer
and the correct alignment of the molecular and electrode levels, we find that
the conductance oscillates with the number of atoms in the chain regardless of
the type of electrode. However, for short chains and Al electrodes the even-odd
periodicity is reversed at equilibrium bond distances.Comment: 14 pages, two-column format, submitted to PR
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