Fused empirical mode decomposition and wavelets for locating combined damage in a truss-type structure through vibration analysis

Structural health monitoring （SHM） is a relevant topic for civil systems and involves the monitoring, data processing and interpretation to evaluate the condition of a structure, in order to detect damage. In real structures, two or more sites or types of damage can be present at the same time. It has been shown that one kind of damaged condition can interfere with the detection of another kind of damage, leading to an incorrect assessment about the structure condition. Identifying combined damage on struc- tures still represents a challenge for condition monitoring, because the reliable identification of a combined damaged condition is a difficult task. Thus, this work presents a fusion of methodologies, where a single wavelet-packet and the empirical mode decom- position （EMD） method are combined with artificial neural networks （ANNs） for the automated and online identification-location of single or multiple-combined damage in a scaled model of a five-bay truss-type structure. Results showed that the proposed methodology is very efficient and reliable for identifying and locating the three kinds of damage, as well as their combinations. Therefore, this methodology could be applied to detection-location of damage in real truss-type structures, which would help to improve the characteristics and life span of real structures.     

Pedagogical influence of interaction with cooperating teachers on the efficacy beliefs of student teachers

Abstract

Cooperating teachers are often identified as some of the most important figures in the preparation of new teachers, and the reasons are not difficult to understand. Surprisingly, however, very little research has been conducted to quantify the effects of cooperating teachers on student teachers. This study examines the impact of student teachers' perceived interactions with their cooperating teachers and the influence that interaction has on student teachers' self‐efficacy for teaching. Results indicate a moderate correlation between perceptions of teaching efficacy and cooperating teacher‐student teacher interactions. Differences were found in the frequency of interaction based on the certification level of the student teacher, with elementary level student teachers perceiving a greater amount of interaction with their cooperating teachers. However, no differences based on certification level were detected in perceived efficacy. Student teachers' perceptions of the level of guidance offered by their cooperating teachers provided the most reliable predictor for their efficacy belief.     

The interplay of learning approaches and self-efficacy in secondary school students’ academic achievement in science

ABSTRACT

The aim of the present investigation was to analyse the role of academic self-efficacy and approaches to learning in general and in Physics and Chemistry academic achievements. The sample comprised 507 secondary school students of two Spanish schools and the study was conducted in the context of a Physics and Chemistry subject. Structural equation models showed that surface motive was the only type of learning approach directly related to performance. Besides, our models revealed that self-efficacy plays an important role as a mediating variable between the surface strategy and the deep motive learning approaches and academic achievement. Gender effects were also studied as girls showed higher levels of achievement both in general performance and in Physics and Chemistry. Implications for science education and suggestions for future research of these findings are also discussed.     

Temporal discounting of aversive consequences in rats

Previous research has extensively evaluated the impact of delay on the value of positive reinforcers, but the study of its impact on the value of aversive consequences is scarce. The present study employed a modification of Evenden and Ryan’s procedure (1996, Psychopharmacology, 128(2), 161–170) to obtain data on temporal discounting of an aversive consequence, with rats as experimental subjects. In the first phase of the procedure, rats chose between one-pellet and four-pellet alternatives; when subjects developed preference for the larger-amount alternative, a shock was added to it, resulting in a loss of preference. In the first experimental condition, the delay to shock was progressively increased within each session from zero to 40 s (ascending delays), which resulted in a recovery of the preference for the larger-amount + shock alternative as the delay to shock was increased. In a subsequent condition (descending delays) the delay to shock was progressively decreased within each session, from 40 to 0 s. In both conditions, the preference for the smaller-amount no-shock alternative was well described by a hyperbolic function. The order of presentation of the delays within the session, ascending or descending, did not alter the relationship between preference and delay to shock. The temporal discounting curve obtained in the present study could represent a baseline for analyzing the impact that diverse environmental and pharmacological variables have on the temporal discounting of aversive consequences.     

What is the key to academic success? An analysis of the relationship between time use and student performance / ¿Dónde está la clave del éxito académico? Un análisis de la relación entre el uso del tiempo y el rendimiento académico

University students’ use of time is one of the most relevant inputs to their education process. The aim of this work is therefore to explore the effect that the time spent on different academic and non-academic activities (collected using a diary) has on student performance, in order to determine which of these activities improve students’ marks. Moreover, we investigate the role of quality variables such as study skills. Using a sample of undergraduate business students, we find that academic activities such as doing assignments in teams, attending university lectures and self study have significant positive effects on students’ marks. It is thus concluded that to improve academic performance it is not only the quantity of time that matters but also quality aspects like the ability to schedule.     

Centre of pressure correlates with pyramid performance in acrobatic gymnastics

Acrobatic gymnasts need excellent balance control to execute pyramids where one gymnast is supported by another. The objectives of this study were: (1) to describe balance performance by assessing the centre of pressure displacement in a group of acrobatic gymnasts executing pyramids; (2) to determine the relationship between the parameters describing the centre of pressure oscillations and pyramid score; and (3) to examine the role of each foot in providing a solid base of support to maintain the balance of the pyramid. Sixteen acrobatic gymnasts grouped in pairs performed a Half pyramid and a Straddle pyramid held for 7 s on two force platforms. Path length, variance, range trajectory, and surface area of the centre of pressure of each foot were examined to analyse the balance of the pyramid. The path length was correlated with the pyramid score (Straddle: p = 0.692 [large]; Half: p = 0.407 [moderate]). There were differences in the functions of each leg to maintain balance, with the non-preferred leg supporting a higher weight of the pyramid while the preferred leg performed control movements to maintain balance. The results suggested that quantitative analysis of balance can provide important information on pyramid performance.     

Grounding participatory action research in rural Colombia: a demonstration study on youth financial inclusion

ABSTRACT

Since the new millennium, the issue of financial inclusion of young people has increasingly gained recognition, especially in relation to those living in deprived circumstances. Financial inclusion can be promoted through education that specifically aims for the strengthening of young persons’ financial capabilities. In 2013, a participatory action research project was started in a rural region of Colombia to improve the research capacity of a local university through the development and implementation of a demonstration project on the financial inclusion of young people. University teachers, students and employees of a financial cooperative were trained in conducting qualitative methods with a specific aim of being responsive to the life stories of their interviewees. This paper shares the experiences from an international team of educational scholars who aim for the democratisation of research capacity and the dissemination of localised knowledge. This is done by working closely together with stakeholders and ultimately giving a voice to youth employed in the informal economy as they are usually the ones being most deprived from access to financial services.     

Dislexia fonémica: decodificación-codificación fonémica y comprensión lectora silenciosa

Resumen

Se estudiaron los procesos fonémicos de decodificación y codificación en relaáón a la comprensión lectora en una muestra de 49 disléxicos de 10 a 12 años, comparándolos con un grupo de 32 lectores normales, pareados por edad, curso y nivel socio-económico. Todos los niños tenían un CI normal y se les aplicó cuatro tests verbales estandarizados, más tareas experimentales de percepción, discriminación e integración auditivo-fonémica y de comprensión.

Se pudo delimitar, dentro de los disléxicos, un subgrupo de ellos con un rendimiento inferior en decodificación de pseudo-palabras, perceptión auditivo-fonémica, comprensión verbal oral y comprensión lectora silenciosa, lo que confirmó la hipótesis principal del estudio. Las diferencias entre disléxicos y lectores normales también fueron significativas. Los procesos fonémicos más estrechamente relaáonados con lectura y deletreo de pseudopalabras fueron discriminación auditiva de palabras similares e inversión oral de secuencias de letras CVC (trigramas). Esta investigación forma parte de un estudio de seguimiento.     

A three dimensional thermoplastic microfluidic chip for robust cell capture and high resolution imaging

We present a low cost microfluidic chip integrating 3D micro-chambers for the capture and the analysis of cells. This device has a simple design and a small footprint. It allows the implementation of standard biological protocols in a chip format with low volume consumption. The manufacturing process relies on hot-embossing of cyclo olefin copolymer, allowing the development of a low cost and robust device. A 3D design of microchannels was used to induce high flow velocity contrasts in the device and provide a selective immobilization. In narrow distribution channels, the liquid velocity induces a shear stress that overcomes adhesion forces and prevents cell immobilization or clogging. In large 3D chambers, the liquid velocity drops down below the threshold for cell attachment. The devices can be operated in a large range of input pressures and can even be handled manually using simple syringe or micropipette. Even at high flow injection rates, the 3D structures protect the captured cell from shear stress. To validate the performances of our device, we implemented immuno-fluorescence labeling and Fluorescence in Situ Hybridization (FISH) analysis on cancer cell lines and on a patient pleural effusion sample. FISH is a Food and Drug Administration approved cancer diagnostic technique that provides quantitative information about gene and chromosome aberration at the single cell level. It is usually considered as a long and fastidious test in medical diagnosis. This process can be easily implanted in our platform, and high resolution fluorescence imaging can be performed with reduced time and computer intensiveness. These results demonstrate the potential of this chip as a low cost, robust, and versatile tool adapted to complex and demanding protocols for medical diagnosis.