1,720,963 research outputs found
On the use of continuum Finite Element and Equivalent Frame models for the seismic assessment of masonry walls
No full textThe assessment of the seismic vulnerability of masonry buildings requires reliable and computationally efficient numerical models. Different modelling strategies can be adopted when studying the global response of these structures, such as Continuum Constitutive Laws Models (CCLM) belonging to Finite Element (FE) models, which may be very accurate but whose use in practice presents several issues (high computational burden, requirement of many input data), and Equivalent Frame (EF) Models, that, even if based on strong simplifications, are now widespread in engineering practice, thanks to their computational efficiency and the need of few mechanical parameters for the structural analysis. The paper discusses the consistent use of these modelling techniques for the seismic analysis of masonry structures. To this aim, a comparison of two approaches (CCL and EF models) is presented focusing at first the attention on the calibration of the constitutive laws through analyses on single panels and then moving to the validation of some simplified assumptions made in the EFM through the analysis of a 2D regular URM wall. For the aim of validation, the CCL model is considered as the reference solution making an accurate comparison with the EF model in terms of generalized forces, drift and damage occurred at element scale and of pushover curve at global scale
Equivalent frame idealization of walls with irregular openings in masonry buildings
Full text linkWithin the framework of modelling of unreinforced masonry structures, the equivalent frame (EF) approach is widely used for the seismic assessment. However, the definition of modelling rules for the EF idealization of walls is not always straightforward. Such rules are typically applied a priori and they can strongly affect the seismic response. This paper aims to investigate the reliability of four existing rules for the a priori identification of the geometry of the piers, i.e. the elements in charge of resisting the horizontal and vertical loads. This constitutes the first main issue within the EF idealization of walls. Continuum finite element (FE)-based numerical solutions are considered as reference to assess the reliability of EF approach for a number of irregular masonry walls case studies. The investigated irregularity deals with the presence of openings with different height at the same storey or the presence of small openings. The critical comparison between FE and EF solutions is made in terms of (i) pushover curves, (ii) damage patterns, (iii) generalized forces, and (iv) drift values at scale of single elements. The results herein achieved allow to provide practical recommendations for the EF walls idealization. In particular, some existing rules for the a priori identification of the geometry of piers already appeared to work properly, while specific precautions appeared to be needed for other rules or in specific cases, which have been identified. More specifically, the rules that may lead to very squat piers appeared to be particularly problematic since may produce a significant underestimation of the ultimate displacement capacity at least when compared to the one estimated by the FE model, assumed as reference solution in the paper. Finally, in the case of small openings, results suggest how the most reliable solution consists of neglecting them in the EF idealization process. To support analysts in this choice, some preliminary indications on the dimensions that identify “small openings” are also provided in the paper
Possible Role of Vitamin D in Celiac Disease Onset
Full text linkBeside skeletal system maintenance and protection, possible extra-calcium roles of vitamin D have been recently described. In particular, studies have investigated possible roles of vitamin D as a key modulator of inflammation and immune mechanisms and of the intestinal mucosa barrier. In this regard, vitamin D has been considered as a factor that affects different conditions such as immune-mediated diseases. The new emerging role of vitamin D and its involvement in immune modulation has led it to be considered as a possible key factor involved in celiac disease (CD) onset. CD is a chronic immune-mediated enteropathy of the small intestine that is triggered by dietary gluten protein exposure in individuals who are genetically predisposed. However, along with gluten, other environmental factors are also involved in CD onset. The renewed interest in a molecule that offers great possibilities for new roles has led to an increase in studies, although there remains a lack of studies aimed at contextualizing the role of vitamin D on CD. This review aims to define the possible role of vitamin D in CD onset as it is presently understood, taking into account potential links among vitamin D, the immune system and CD
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Nutritional properties of rice varieties commonly consumed in Italy and applicability in Gluten free diet
Full text linkGluten-free diets are often characterized by an inadequate intake of nutrients and are generally monotonous for the limited number of products celiac patients can use. As rice is the most used cereal by celiac consumers, studying rice varieties nutritional characteristics is of interest to manage diet quality and variety. Proteins, total carbohydrates and amylose content of six rice varieties (Ribe, Vialone Nano, Carnaroli, Arborio, Basmati, and Fragrance) were analyzed. Analyses were performed in raw products and after boiling, stewing, and microwaving. A decrease of proteins and total carbohydrates amount was observed in cooked rice. The same was reported for amylose content with boiling showing the highest loss (average retained amylose 53%). Considering amylose percentage with respect to total carbohydrates, each variety showed either an increase or a decrease depending on cooking method. The highest values were obtained with stewing above all for Basmati rice and Arborio rice. However, exceptions can be underlined as Carnaroli rice, showing the highest percentage when boiled. In this context, nutritional characteristics of cooked rice varieties appear to be of great importance to increase specific nutritional knowledge to better manage gluten-free diets
Impact of 24 weeks of strength training coupled to endurance training on endurance performance (hero dolomites 2019)
Full text linkDespite reports are still equivocal, in recent years different studies reported how strength training could impact positively on endurance performance. The aim of this study was to evaluate the impact of a long-term strength coupled to endurance training protocol in comparison with endurance training protocol on cycling performance. 14 trained amateurs' cyclists (males; 27,03 ± 3,75 years; 177,15 ± 5,69 cm; 69,67 ± 8,53 kg; 22,2 ± 1,67 BMI) that completed the Hero Dolomites 2018 competition and signed to the 2019 edition (86 km, 4500 m) participated to the study. 7 of them (treated) followed a 24 weeks strength training coupled to endurance training program to increase performance, the other (untreated) followed their endurance training routines without any specific resistance training protocol. FTP (Functional Threshold Power) test and 1RM (One Repetition Maximum) test (barbell squat and leg press 45°) were planned at week 1, week 8, week 16 and week 24. 2019 race times were compared to 2018 once. Treated individuals showed increased strength (barbell squat: +29,7 ± 7,8 kg; leg press 45°: +53,5 ± 13,1 kg) and FTP (+23,2 ± 9,3 W) from week 1 to week 24. Both treated and untreated individuals improved their race time from 2018 to 2019 (treated: -51,4 ± 24,6 m; untreated: -11,8 ± 14,4 m). Treated individuals improved significantly race time from 2018 compared to untreated individuals (p<0,05). Structured and periodized strength sessions can be incorporated and maintained for the entire duration of a 24 weeks training program impacting positively on endurance performance
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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