1,350 research outputs found
Experimental measurement of bridge deflection using Digital Image Correlation
Civil engineering bridges usually face a multitude of loads, ranging from strong winds to intense traffic. Thus, it is important to understand their behaviour for adequate maintenance design and prevention of catastrophic failure.
The present work reports an image sensing methodology for deflection measurement that was successfully employed on the Entre-Águas bridge in Caniçal, Madeira, Portugal. For the application of two-dimensional Digital Image Correlation, it was necessary to build and deploy a patterned target onto the bridge in the monitored area and a camera setup in stable ground on a plane orthogonal to the target. Two different 2D DIC software packages were used for calculations, one commercial and one self-developed, enabling their comparison and increasing the confidence in the experimental results.
The developed system was applied in order to analyze the effects of the passage of 30-ton trucks in the bridge, with promising results.info:eu-repo/semantics/publishedVersio
Shape acquisition of rotating objects based on Laser Line Scanning
The present work proposes a methodology for 3D shape acquisition of objects through rotation-based Laser Line Scanning. This
enables the acquisition of an object's 3D shape from multiple views,
which leads to a more complete and accurate model
Single Lap Joints Numerical Modelling and Comparison with Experimental Testing
Adhesive bonding is a joining technique which has been extensively employed in structural design as its ability to join different types of materials allows higher freedom for designers when choosing materials. One of the most common joint configuration used is the single lap joint configuration. In this work a set of experimental procedures were undertaken to characterize a structural adhesive and model the behaviour of a single lap joint manufactured using this adhesive. Two types of surface preparations were used to study its effect in single lap joint strength
Crack Closure Effects on Fatigue Crack Propagation Rates: Application of a Proposed Theoretical Model
Structural design taking into account fatigue damage requires a thorough knowledge of the behaviour of materials. In addition to the monotonic behaviour of the materials, it is also important to assess their cyclic response and fatigue crack propagation behaviour under constant and variable amplitude loading. Materials whenever subjected to fatigue cracking may exhibit mean stress effects as well as crack closure effects. In this paper, a theoretical model based on the same initial assumptions of the analytical models proposed by Hudak and Davidson and Ellyin is proposed to estimate the influence of the crack closure effects. This proposal based further on Walker’s propagation law was applied to the P355NL1 steel using an inverse analysis (back-extrapolation) of experimental fatigue crack propagation results. Based on this proposed model it is possible to estimate the crack opening stress intensity factor, Kop, the relationship between U=ΔKeff/ΔK quantity and the stress intensity factor, the crack length, and the stress ratio. This allows the evaluation of the influence of the crack closure effects for different stress ratio levels, in the fatigue crack propagation rates. Finally, a good agreement is found between the proposed theoretical model and the analytical models presented in the literature
Leptin modulates human Sertoli cells acetate production and glycolytic profile: a novel mechanism of obesity-induced male infertility?
AbstractHuman feeding behavior and lifestyle are gradually being altered, favoring the development of metabolic diseases, particularly type 2 diabetes and obesity. Leptin is produced by the adipose tissue acting as a satiety signal. Its levels have been positively correlated with fat mass and hyperleptinemia has been proposed to negatively affect male reproductive function. Nevertheless, the molecular mechanisms by which this hormone affects male fertility remain unknown. Herein, we hypothesize that leptin acts on human Sertoli cells (hSCs), the “nurse cells” of spermatogenesis, altering their metabolism. To test our hypothesis, hSCs were cultured without or with leptin (5, 25 and 50ng/mL). Leptin receptor was identified by qPCR and Western blot. Protein levels of glucose transporters (GLUT1, GLUT2 and GLUT3), phosphofructokinase, lactate dehydrogenase (LDH) and monocarboxylate transporter 4 (MCT4) were determined by Western Blot. LDH activity was assessed and metabolite production/consumption determined by proton nuclear magnetic resonance. Oxidative damage was evaluated by assessing lipid peroxidation, protein carbonilation and nitration. Our data shows that leptin receptor is expressed in hSCs. The concentration of leptin found in lean, healthy patients, upregulated GLUT2 protein levels and concentrations of leptin found in lean and obese patients increased LDH activity. Of note, all leptin concentrations decreased hSCs acetate production illustrating a novel mechanism for this hormone action. Moreover, our data shows that leptin does not induce or protect hSCs from oxidative damage. We report that this hormone modulates the nutritional support of spermatogenesis, illustrating a novel mechanism that may be linked to obesity-induced male infertility
Educational and economic determinants of food intake in Portuguese adults: a cross-sectional survey
BACKGROUND: Understanding the influences of educational and economic variables on food consumption may be useful to explain food behaviour and nutrition policymaking. The aim of this study was to evaluate the importance of educational and economic factors in determining food pattern in Portuguese adults. METHODS: A cross-sectional study in a representative sample of Portuguese adults (20977 women and 18663 men). Participants were distributed in four categories according to years of education (≤4, 5–9, 10–12, and >12) and income (≤314 euros, 315–547 euros, 548–815 euros, and >815 euros). Logistic regression models were fitted to estimate the magnitude of the association between food groups and education/income, adjusting for confounders. RESULTS: In both genders, the odds favouring milk, vegetable soup, vegetables, fruit, and fish consumption, increased significantly with education, for those having >12 years of education compared to those with ≤4 years; the odds favouring wine, and spirits consumption decreased significantly with education, for those having >12 years of education compared to those with ≤4 years. In males, the odds favouring starchy foods and meat consumption decreased significantly with income, while for milk, the odds increased with higher income (those having >815 euros compared to those with ≤314 euros). CONCLUSIONS: The low and high income groups are or tend to be similar in regard to several food groups consumption, and access to education/information appears to be the key element to a better food pattern as indicated by higher frequency of milk, vegetable soup, vegetables, fruit, and fish consumption
Assessing the symptoms of Internet Gaming Disorder among college/university students: An international validation study of a self-report
The present study evaluated the psychometric properties of a self-report scale for assessing Internet Gaming Disorder (IGD) symptoms according to the DSM-5 and ICD-11 among 3270 college/university students (2095 [64.1%] females; age mean 21.6 [3.1] years) from different countries worldwide. Croatian, English, Polish, Portuguese, Serbian, Turkish, and Vietnamese versions of the scale were tested. The study showed that symptoms of IGD could be measured as a single underlying factor among college/university students. A nine item-symptom scale following DSM-5, and a short four-item scale representing the main ICD-11 symptoms, had sound internal consistency and construct validity. Three symptom-items were found non-invariant across the language samples (i.e., preoccupation with on-line gaming, loss of interests in previous hobbies and entertainment, and the use of gaming to relieve negative moods). This study provides initial evidence for assessing IGD symptoms among college/university students and will hopefully foster further research into gaming addiction in this population worldwide especially with taking into account language/cultural differences
Promoting the use of the PI-QUAL score for prostate MRI quality: results from the ESOR Nicholas Gourtsoyiannis teaching fellowship
OBJECTIVES: The Prostate Imaging Quality (PI-QUAL) score is a new metric to evaluate the diagnostic quality of multiparametric magnetic resonance imaging (MRI) of the prostate. This study assesses the impact of an intervention, namely a prostate MRI quality training lecture, on the participant's ability to apply PI-QUAL. METHODS: Sixteen participants (radiologists, urologists, physicists, and computer scientists) of varying experience in reviewing diagnostic prostate MRI all assessed the image quality of ten examinations from different vendors and machines. Then, they attended a dedicated lecture followed by a hands-on workshop on MRI quality assessment using the PI-QUAL score. Five scans assessed by the participants were evaluated in the workshop using the PI-QUAL score for teaching purposes. After the course, the same participants evaluated the image quality of a new set of ten scans applying the PI-QUAL score. Results were assessed using receiver operating characteristic analysis. The reference standard was the PI-QUAL score assessed by one of the developers of PI-QUAL. RESULTS: There was a significant improvement in average area under the curve for the evaluation of image quality from baseline (0.59 [95 % confidence intervals: 0.50-0.66]) to post-teaching (0.96 [0.92-0.98]), an improvement of 0.37 [0.21-0.41] (p < 0.001). CONCLUSIONS: A teaching course (dedicated lecture + hands-on workshop) on PI-QUAL significantly improved the application of this scoring system to assess the quality of prostate MRI examinations. KEY POINTS: • A significant improvement in the application of PI-QUAL for the assessment of prostate MR image quality was observed after an educational intervention. • Appropriate training on image quality can be delivered to those involved in the acquisition and interpretation of prostate MRI. • Further investigation will be needed to understand the impact on improving the acquisition of high-quality diagnostic prostate MR examinations
Produção de memórias falsas com listas de associados : análise do efeito do nível de processamento e da natureza da prova de memória
As memórias falsas têm sido amplamente estudadas com base num procedimento experimental designado paradigma DRM (Deese/Roediger/McDermott). Esse paradigma promove a criação de ilusões de memória a partir da apresentação de listas de palavras associadas a um item que não consta da lista. Uma das linhas de investigação com o paradigma DRM visa identificar o momento da criação das falsas memórias e explicar os mecanismos que estão na sua origem. Neste artigo, pretendemos fazer uma revisão da investigação sobre o efeito do nível de processamento e da natureza da tarefa de memória na facilitação ou inibição da produção de memórias falsas com listas de associados semânticos.False memories have been widely studied using an
experimental procedure called DRM paradigm (Deese/Roediger/McDermott). This
paradigm produces memory illusions due to the presentation of lists of words
associated to a critical nonpresented word. One line of research on this topic aims at
identifying the moment when the false memories are created and the explanation of
the mechanisms underling false memories. In this paper we present a review about
the effect of level-of-processing and the nature of memory task for the boost or
inhibition of false memories created by means of lists of semantic associates.Le paradigme DRM (Deese/Roediger/McDermott) est
un des plus connus et plus robustes parmi les études des faux mémoires dans le
contexte du laboratoire. Ce paradigme permet la création d illusions de mémoire à
partir des mots sémantiquement associés à un item qui n a pas été présenté. Au milieu
des investigations basées sur le paradigme DRM il y a des études dont l objectif est
d identifier e d´expliquer les mécanismes qui sont à l origine de la production des
faux mémoires. Plus spécifiquement, on a pour but de faire une révision de la
recherche sur l effet du niveau de codification et de la nature des tâches de mémoire
sur la facilitation ou l´inhibition de la production de faux mémoires à partir des mots
sémantiquement associés.Los falsos recuerdos han sido muy estudiados mediante
la aplicación del paradigma DRM (Deese/Roediger/McDermott). El paradigma
permite producir ilusiones de memoria tras la presentación de listas de palabras
asociadas a una palabra que no se incluye en la lista. Una de las líneas de investigación
que utilizan el paradigma DRM busca identificar el preciso momento de la creación
de falsos recuerdos y explicar los mecanismos que originan ese efecto. El objetivo de
este artículo es hacer una revisión de la investigación sobre el efecto de los niveles
de procesamiento y la naturaleza de la tarea de memoria en la facilitación y inhibición
de la producción de falsos recuerdos con listas de asociados semánticos.Fundação para a Ciência e a Tecnologia (FCT)Centro de Investigação em Psicologia da Universidade do Minho (CIPsi
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