Search results for " methodology"
showing 10 items of 575 documents
Enhanced extraction of astragalosides from Radix Astragali by negative pressure cavitation-accelerated enzyme pretreatment.
2010
The optimal conditions for extraction of astragalosides III and IV (AGs III and IV) in Radix Astragali by negative pressure cavitation-accelerated enzyme pretreatment were studied on the basis of a Box-Behnken design and response surface methodology. Experimental results showed that negative pressure, amount of enzyme and incubation temperature were the main factors governing the enzyme pretreatment of Radix Astragali. The optimum parameters were obtained as follows: negative pressure -0.08 Mpa, amount of enzyme 1.48% (w/w of materials) and incubation temperature 45 degrees C. Under the optimal conditions, the maximal extraction yields of AGs III and IV were 0.103 and 0.325 mg/g, which were…
Effects of Age and Playing Tactics on the Individual Tactical Behavior in U10 and U12 Elite Spanish Soccer Players
2022
The aim of this paper was to explore the effects of age and playing tactics on the individual tactical behavior and performance in young soccer players. A total of 1247 individual possessions during 16 knockout matches from LaLiga Promises U12 tournament (n = 621) and LaLiga U10 Iscar Cup (n = 626) were analyzed by observational methodology. Multilevel and multivariate logistic regression models were created to explain the interdependent effects of age category and playing tactics on the individual tactical behavior and performance. Youth players performed most of their actions against defensive pressure (72.5%), during offensive support (91.3%) and receiving the ball facing forward (62.6%)…
Analysis of Teaching Personal and Social Responsibility model-based programmes applied in USA and Spain
2013
Caballero-Blanco P, Delgado-Noguera, MA, Escarti-Carbonell, A. Analysis of Teaching Personal and Social Responsibility model-based programmes applied in USA and Spain. J. Hum. Sport Exerc. Vol. 8, No. 2, pp. 427-441, 2013. Over the last three decades, several studies have applied Hellison’s Teaching Personal and Social Responsibility (TPSR) model; most of them have generated strong empirical evidences that support that theoretical framework. TPSR is a programme for positive youth development through physical activity. This article compares the different studies that have implemented the TPSR model in the United States and Spain. This paper reviews those researches by analysing their key fea…
Optimization of microwave-assisted extraction of polyphenols from Quercus bark
2015
Abstract Box–Behnken response surface methodology was used to investigate and optimize microwave assisted extraction (MAE) (treatment power and time) of antioxidant compounds, especially polyphenols, from bark extracts. Moreover, the effects of solvent composition (methanol and ethanol) particle size, and pH conditions were evaluated and optimized. In addition, the effects of MAE were compared to conventional solvent extraction at room temperature and reflux extraction (at 100 °C). The results indicated that all process variables had a significant effect on polyphenol and antioxidant recovery, except for methanol (p > 0.05). For instance, TPC and antioxidant activity were increased when hig…
Molecular profiling and function of exosomes derived from Non-Small Cell Lung Cancer. Diagnostic, predictive and prognostic biomarkers.
2019
Abstract: abstract not available
Scientific studies on writing in second language learning (2005-2017)
2019
Este artículo revisa críticamente las líneas temáticas que desde 2005 hasta 2017 se han publicado sobre Second Language Writing (SLW) con el objetivo de presentar un análisis de las tendencias predominantes en las publicaciones indexadas en SCOPUS. Como metodología de estudio se ha procedido a la selección de aquellas contribuciones que han recibido 60 citas o más. De la revisión de literatura científica realizada se concluye que son tres las líneas de investigación mayoritarias: el proceso de composición o redacción del texto escrito; la retroalimentación que el docente ofrece al aprendiz; y la escritura en línea de una L2. Las conclusiones señalan la necesidad de profundizar en la investi…
La escritura expresiva en la orientación. Una metodología educativa para la construcción del proyecto de vida personal y profesional
2020
La scrittura espressiva adottata a scuola come strumento di autorientamento dell’adolescente di 17-18 anni non sostituisce l’intervento educativo dell’insegnante, piuttosto può considerarsi una tecnica efficace per raccogliere tutte le informazioni necessarie con cui formare, con il consenso dell’alunno e insieme a lui, un quadro esaustivo in cui includere lo stato attuale delle sue competenze, le sue attitudini, i suoi interessi, le sue motivazioni, la sua storia formativa, il suo profilo di personalità, i suoi limiti, nonché i suoi obiettivi e le modalità concrete con cui egli pensa di raggiungerli. Essa è pertanto un metodo educativo con cui gli studenti che si approssimano a svolgere gl…
On the interpretability and computational reliability of frequency-domain Granger causality
2017
This Correspondence article is a comment which directly relates to the paper “A study of problems encountered in Granger causality analysis from a neuroscience perspective” (Stokes and Purdon, 2017). We agree that interpretation issues of Granger causality (GC) in neuroscience exist, partially due to the historically unfortunate use of the name “causality”, as described in previous literature. On the other hand, we think that Stokes and Purdon use a formulation of GC which is outdated (albeit still used) and do not fully account for the potential of the different frequency-domain versions of GC; in doing so, their paper dismisses GC measures based on a suboptimal use of them. Furthermore, s…
Group Importance Sampling for particle filtering and MCMC
2018
Bayesian methods and their implementations by means of sophisticated Monte Carlo techniques have become very popular in signal processing over the last years. Importance Sampling (IS) is a well-known Monte Carlo technique that approximates integrals involving a posterior distribution by means of weighted samples. In this work, we study the assignation of a single weighted sample which compresses the information contained in a population of weighted samples. Part of the theory that we present as Group Importance Sampling (GIS) has been employed implicitly in different works in the literature. The provided analysis yields several theoretical and practical consequences. For instance, we discus…
Unsupervised Anomaly and Change Detection With Multivariate Gaussianization
2022
Anomaly detection (AD) is a field of intense research in remote sensing (RS) image processing. Identifying low probability events in RS images is a challenging problem given the high dimensionality of the data, especially when no (or little) information about the anomaly is available a priori. While a plenty of methods are available, the vast majority of them do not scale well to large datasets and require the choice of some (very often critical) hyperparameters. Therefore, unsupervised and computationally efficient detection methods become strictly necessary, especially now with the data deluge problem. In this article, we propose an unsupervised method for detecting anomalies and changes …