170 research outputs found
El paleógeno del sector suroccidental de la Cuenca del Duero: nueva división estratigráfica y controles sobre su sedimentación
A Paleogene four-fold stratigraphical division is proposed here as result from the detailed studies carried out during the elaboration of 22 sheets of the Geological Map of Spain (E. 1:50.000). This units (T.S.U.) are limited by regional discordances and they have a Upper Cretaceous to Oligocene ages. The previous stratigraphical schemes are rearranged due to the different stratigraphicalrelations observed between the lithostratigraphical units proPosed by other workers (Jiménez, 1970; Corrochano, 1977; Alonso, 1981 ...). An Upper Cretaceous-Paleocene age is assumed to T.S.U. MC which is mainly composed by siliciclastic sediments strongly silicified forming a FU megasequence. It is interpretated as braided streams that flowed downslope filling paleovalleys eroded onto Paleozoic materials. Mineralogical features point to a tropical climate. Lower Eocene (T.S.U. P1) is identified in the Salamanca area, where it was considered as lacking. It is composed by arkosic sediments forming a CU megasequence. Fossil faunas of this T.S.U. record a subtropical climate. It is observed a transition from high sinuosity streams to braided ones. T.S.U. P2 (Middle Eocene-Lower Oligocene) is composed of two lithostratigraphical units previously considered as bounded by a discordance (Alonso, 198 1). It has a subarkosic to lithic nature and forms a CU megasequence. This unit records a subtropical climate with short arid periods and is interpretated as braided streams showing an increasing stability and enviromental energy to the top. T.S.U. P3 (Upper Oligocene) is composed by arkosic sediments previously considered of Vallesian (Middle to Upper Miocene) age. They form a CU megasequence that records braided streams prograding basin ward from higher areas. Palinological associations and pedological features indicate an arid mediterranean climate with long arid periods and a short rainy season with strong floods. We consider that most of Lower Miocene sediments are of Paleogene age. They are afected by a widespread alteration profile developed along Lower Miocene that masked its more significative features. Sedimentological analysis of T.S.U. shows that its megasequentiality is related to the rates of tectonical uplift of source areas whereas a distensive regime developed in the sedimentation basin
Metodología para la Creación de una Interfaz Cerebro-Computador Aplicada a la Identificación de la Intención de Movimiento
ResumenLas Interfaces Cerebro-Computador proporcionan un canal para enviar órdenes al mundo exterior haciendo uso de medidas electrofisiológicas de la actividad cerebral. En este artículo se presenta la combinación de un método de selección de características y un algoritmo de clasificación probabilístico para construir el modelo predictivo de la intención anticipada de movimiento voluntario de pacientes con temblor a partir de un solo ensayo. Los resultados obtenidos muestran una potencial de discriminación del 70%, una tasa de error aceptable (6.6%) y una rápida respuesta (cada 250ms), lo que indica que esta combinación es una buena base para la construcción de ICCs que no requieran entrenamiento del usuario de forma personalizada, asíncrona y adaptativa
Evaluación reproductiva en bovinos.
El aumento de la producción en las explotaciones ganaderas requiere de la maximización de la eficiencia reproductiva. Los avances en el conocimiento de los diferentes aspectos de la biología animal, permiten obtener modificaciones en los ritmos de los ciclos reproductivos para lograr mayores beneficios. La sincronización de los ciclos estrales, ofrece ventajas en la producción animal. Su aplicación correcta requiere del conocimiento de las bases fisiológicas y endocrinológicas. En este trabajo se analizaron los factores que determinan la eficiencia reproductiva (formación de gametos, ovolación, fecundación, gestación, parto), los parámetros para medir la actividad reproductiva (días abiertos, intervalo entre partos, número de servicios por concepción, tasa de no retorno, tasa de natalidad, índice de fertilidad), los factores que modifican la fertilidad en el ganado (genéticos, anomalías anatómicas, alteraciones endocrinas, ambientales), las enfermedades más comunes que afectan la actividad reproductiva (brucelosis, vibriosis, leptospirosis, trichomoniasis, complejo viral) y la sincronización del ciclo estralGanado de leche-Ganadería lech
Rendimientos productivos y calidad de la canal de hembras, machos castrados quirurgicamente y machos inmunocastrados procedentes de líneas paternas duroc y pietrain
Tradicionalmente la castración quirúrgica ha sido la práctica más habitual en la producción de cerdo blanco destinado a la industria de productos cárnicos curados. La castración quirúrgica conlleva un empeoramiento de los rendimientos productivos y penaliza el bienestar animal. Como alternativa ha surgido la inmunización de los cerdos contra el factor de liberación de la gonadotropina (GnRH) (Fàbrega et al., 2010). La inmunocastración suprime la función testicular (Zamaratskaia et al., 2008) y reduce la producción de androsterona (Dunshea et al., 2001) y escatol (Matthews et al., 2000) así como la agresividad (Jaros et al., 2005). Por tanto, la inmunocastración puede ser una alternativa a la castración física en situaciones comerciales. Por otro lado, para la obtención de productos curados se precisan canales con más grasa y mayor proporción de partes nobles que para productos frescos, por lo que se utilizan estrategias como aumentar el peso al sacrificio o el cruce con líneas paternas específicas. El objetivo de este estudio fue evaluar el rendimiento productivo y la calidad de la canal de hembras enteras (HE), machos castrados (MC) y machos inmunocastrados (MI) procedentes de genéticas paternas Duroc (DU) y Pietrain (PI) con un peso al sacrificio de 134 kg
Sustainability in the design of an itinerant cultural exhibition. Study of two alternatives
The sustainability improvement of museums and exhibitions is a recent concern for multiple organisations. The application of sustainability criteria is one of the most important strategies of innovation in design activities, products, and service systems. This study analyses the sustainability of two alternatives to an itinerant cultural exhibition service. The exhibition travels to 12 destinations over 3 years and is within a space of 300 m2. In the first alternative, the contents are printed and exposed on a physical medium, and in the second, audiovisual media projects the contents on the walls. Life cycle sustainability assessment is applied to evaluate the impacts in the environmental dimension and the economic and social dimensions. The calculation of indicators, such as the greenhouse gas emissions, total costs, and working time, which are referred to each sustainability dimension, is conducted. A descriptive, comparative study was performed to identify the impact factors with a higher incidence. The results demonstrate that the audiovisual exhibition is more sustainable than the printed exhibition, with a difference of 8.7%, 7%, and 6.6% in GWP100, CE, and TW indicators, respectively. © 2021 by the authors. Licensee MDPI, Basel, Switzerland
Evaluating anemometer drift: A statistical approach to correct biases in wind speed measurement
Recent studies on observed wind variability have revealed a decline (termed “stilling”) of near-surface wind speed during the last 30–50 years over many mid-latitude terrestrial regions, particularly in the Northern Hemisphere. The well-known impact of cup anemometer drift (i.e., wear on the bearings) on the observed weakening of wind speed has been mentioned as a potential contributor to the declining trend. However, to date, no research has quantified its contribution to stilling based on measurements, which is most likely due to lack of quantification of the ageing effect. In this study, a 3-year field experiment (2014–2016) with 10-minute paired wind speed measurements from one new and one malfunctioned (i.e., old bearings) SEAC SV5 cup anemometer which has been used by the Spanish Meteorological Agency in automatic weather stations since mid-1980s, was developed for assessing for the first time the role of anemometer drift on wind speed measurement. The results showed a statistical significant impact of anemometer drift on wind speed measurements, with the old anemometer measuring lower wind speeds than the new one. Biases show a marked temporal pattern and clear dependency on wind speed, with both weak and strong winds causing significant biases. This pioneering quantification of biases has allowed us to define two regression models that correct up to 37% of the artificial bias in wind speed due to measurement with an old anemometer
Thinning of the Monte Perdido Glacier in the Spanish Pyrenees since 1981
This paper analyzes the evolution of the Monte Perdido Glacier, the third largest glacier in the Pyrenees, from 1981 to the present. We assessed the evolution of the glacier''s surface area by analysis of aerial photographs from 1981, 1999, and 2006, and changes in ice volume by geodetic methods with digital elevation models (DEMs) generated from topographic maps (1981 and 1999), airborne lidar (2010) and terrestrial laser scanning (TLS, 2011, 2012, 2013, and 2014) data. We interpreted the changes in the glacier based on climate data from nearby meteorological stations. The results indicate that the degradation of this glacier accelerated after 1999. The rate of ice surface loss was almost three times greater during 1999-2006 than during earlier periods. Moreover, the rate of glacier thinning was 1.85 times faster during 1999-2010 (rate of surface elevation change = -8.98 ± 1.80 m, glacier-wide mass balance = -0.73 ± 0.14 m w.e. yr-1) than during 1981-1999 (rate of surface elevation change = -8.35 ± 2.12 m, glacier-wide mass balance = -0.42 ± 0.10 m w.e. yr-1). From 2011 to 2014, ice thinning continued at a slower rate (rate of surface elevation change = -1.93 ± 0.4 m yr-1, glacier-wide mass balance = -0.58 ± 0.36 m w.e. yr-1). This deceleration in ice thinning compared to the previous 17 years can be attributed, at least in part, to two consecutive anomalously wet winters and cool summers (2012-2013 and 2013-2014), counteracted to some degree by the intense thinning that occurred during the dry and warm 2011-2012 period. However, local climatic changes observed during the study period do not seem sufficient to explain the acceleration of ice thinning of this glacier, because precipitation and air temperature did not exhibit statistically significant trends during the study period. Rather, the accelerated degradation of this glacier in recent years can be explained by a strong disequilibrium between the glacier and the current climate, and likely by other factors affecting the energy balance (e.g., increased albedo in spring) and feedback mechanisms (e.g., heat emitted from recently exposed bedrock and debris covered areas)
Efecto de la densidad en cebo sobre el rendimiento productivo, la composición de la carne y el perfil de ácidos grasos de cerdos sacrificados con 110 kg de peso
El número de cerdos por cuadra y la densidad influyen sobre el rendimiento productivo
(Edmons et al., 1998). Además, la densidad de cría puede afectar a la calidad de la canal y
de la carne (Estevez et al., 2003), ya que una reducción del espacio disponible da lugar a
peleas y mordeduras de colas. Sin embargo, la producción de carne por m
2
aumenta con la
densidad con un mejor aprovechamiento de la superficie disponible. Por otro lado, la
densidad podría afectar de distinto modo a hembras (HE) y a machos castrados (MC)
debido posiblemente al menor consumo voluntario de pienso de las HE. A este particular,
Hamilton et al. (2003) observaron que a altas densidades de cría las HE fueron
relativamente más magras mientras que los MC eran relativamente más grasos. Cambios en
la densidad de cría, pueden afectar a la composición en ácidos grasos de la canal debido a
cambios en el consumo y a la utilización del alimento (Nürnberg et al., 1998). El objetivo de
este estudio fue comparar el efecto de la densidad de cebo de HE y MC con alto potencial
de crecimiento, sobre el rendimiento productivo y la composición de la carne y el perfil de
ácidos grasos en cerdos de 19 a 109 kg PV
Efficacy and safety of the combination of pravastatin and sorafenib for the treatment of advanced hepatocellular carcinoma (ESTAHEP clinical trial)
Pravastatin has demonstrated anti-tumor activity in preclinical and clinical studies. This multicentric randomized double-blind placebo-controlled phase II study (NCT01418729) investigated the efficacy and safety of sorafenib + pravastatin combination on the overall survival (OS) and time to progression (TTP) of patients with advanced hepatocellular carcinoma (aHCC). A total of 31 patients were randomized. Median OS did not differ between both groups (12.4 months for the sorafenib + pravastatin group vs. 11.6 months for the control group). Of note, however, the radiological TTP was higher in patients treated with sorafenib + pravastatin than in the control group (9.9 months vs. 3.2 months; p = 0.008). Considering all the study population, the presence of portal vein thrombosis (PVT) was associated with worse OS, being lower in patients with PVT compared to patients without PVT (6.3 months vs. 14.8 months; p = 0.026). Data also showed a decrease in OS in patients with vascular invasion (VI) compared to patients who did not present it (6.3 months vs. 14.8 months; p = 0.041). The group of patients without dermatological events (DE) showed lower OS (6.9 months vs. 14.5 months; p = 0.049). In conclusion, combination of sorafenib + pravastatin was safe and well-tolerated, prolonging the TTP of patients with aHCC but not improving the OS compared to sorafenib + placebo. The absence of PVT and VI and the development of DE are positive prognostic factors of sorafenib response
Neurophysiologic Assessment of Motor Imagery Training by Using Virtual Reality for Pediatric Population with Cerebral Palsy
[ES] Existen diversas evidencias que indican que los déficits motores en los pacientes de parálisis cerebral se asocian con problemas en la planificación motora que, a su vez, apuntan a una mermada capacidad para imaginar movimientos. La imaginación motora se ha revelado como una herramienta efectiva en el aprendizaje y la adquisición de habilidades motoras ya que comparte estructuras neuronales similares con la ejecución motora. En este trabajo se presenta un paradigma basado en un juego de realidad virtual para guiar la actividad mental del paciente que sirve a dos fines: estudiar su capacidad de imaginar movimientos e implicar y motivar al paciente en el entrenamiento de dicha capacidad. El estudio ha involucrado cuatro niños con parálisis cerebral espástica (edad media = 13.25 años, DS = 1.5) con lesión cerebral bilateral. Los resultados obtenidos del análisis de su actividad electroencefalográfica muestran que estos pacientes son capaces de emplear la imaginación motora en una tarea de marcha, indicada por la presencia del fenómeno ERD (Event Related Desynchronization) en zonas corticales motoras, independientemente de su nivel funcional y de los miembros afectados.[EN] There are several evidences showing that motor disorders in patients with cerebral palsy are associated with problems in motor planning, which, in turn, denote a diminished capability to imagine movements. Motor imagery appears like an effective means in learning and acquiring motor skills since it shares similar neural structures to those ones used in motor execution. In this paper, a paradigm based on a virtual reality game that drives the patient’s electroencephalographic signal is presented. This study aims, on the one hand, to analyze the patients’ ability of imagining movements and, on the other hand, to involve and motivate them in order to implement this ability. The research work has engaged four children with spastic cerebral palsy (mean age = 13.25, SD = 1.5) with bilateral brain damage. After analyzing their electroencephalographic signal, the results show that these patients are able of using motor imagery in a walking task, as indicated by the presence of ERD (event related desynchronization) in cortical motor areas, regardless their functional impairment and affected body extremities.Este trabajo ha sido financiado parcialmente por los proyectos
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