1,721,055 research outputs found
Vulnerable Road Users. Numerical and Experimental Reconstruction of Cyclist Accidents in Urban Areas
No full textMost cycling accidents occur in urban areas and involve car collisions. In an attempt to define a Finite Element (FE) model of cyclist and bike that can correctly replicate the accident scenario, a numerical experimental analysis has been conducted. The numerical reconstruction is validated by means of results comparison and correlation with experimental tests. A FE bike model has been developed and verified. The available Hybrid III FE model has been modified with respect to its posture to combine it with the bike model previously defined. The whole bike and dummy model has been analysed in actual accident scenarios. The scenarios analysed differ in bike-car angle, velocity, car vehicle model. The focus has been on cyclist injuries: typology and severity. The results of the research intended to define injury threshold levels and the differences in injuries with and without protective garments, in addition with the definition of a reliable bike-dummy numerical model. A series of car-bike impacts was simulated using the bike FE model and combined with the Hybrid III FE model. The numerical simulations have been performed in LS-DYNA FE solver, which gave the possibility to reproduce crash impact scenario. The bike FE model has been created in Hypermesh and imported in LS-DYNA, where analysis have been conducted to validate the model. In the simulations, impact velocity, bike-car angle and vehicle model were varied. The performance of the model was assessed comparing the experimental test performed at La.S.T. (Laboratory of Transport Safety) at Politecnico di Milano under comparable conditions. The Hybrid III Anthropomorphic Test Device has been instrumented as needed (head accelerometers, neck load cells, chest accelerometers, chest deflection transducers, femur force transducers). It has been tied to a city bike model, selected on the base of urban accident database. The research is funded by ASAIS EVU Italia. Keywords: Vulnerable road users, Cyclist accident, Head Injury, Brain Injury, Hybrid III, LS-DYN
Sex/Gender- and Age-Related Differences in β-Adrenergic Receptor Signaling in Cardiovascular Diseases
Full text linkSex differences in cardiovascular disease (CVD) are often recognized from experimental and clinical studies examining the prevalence, manifestations, and response to therapies. Compared to age-matched men, women tend to have reduced CV risk and a better prognosis in the premenopausal period. However, with menopause, this risk increases exponentially, surpassing that of men. Although several mechanisms have been provided, including sex hormones, an emerging role in these sex differences has been suggested for β-adrenergic receptor (β-AR) signaling. Importantly, β-ARs are the most important G protein-coupled receptors (GPCRs), expressed in almost all the cell types of the CV system, and involved in physiological and pathophysiological processes. Consistent with their role, for decades, βARs have been considered the first targets for rational drug design to fight CVDs. Of note, β-ARs are seemingly associated with different CV outcomes in females compared with males. In addition, even if there is a critical inverse correlation between β-AR responsiveness and aging, it has been reported that gender is crucially involved in this age-related effect. This review will discuss how β-ARs impact the CV risk and response to anti-CVD therapies, also concerning sex and age. Further, we will explore how estrogens impact β-AR signaling in women
Lack of association between Interleukin-18 gene promoter polymorphisms and onset of Alzheimer's disease
No full textNALP1/NLRP1 genetic variants are associated with Alzheimer disease.
No full textAlzheimer disease (AD) is a complex neurodegenerative disease. Genetic and molecular studies have confirmed that in the human brain, amyloid-β fibrils can induce, through the activation of NALP1 inflammosome, inflammatory and apoptotic responses involved in the pathogenesis of AD. Considering that AD pathogenesis is multifactorial, we hypothesized that NALP1/NLRP1 could be a susceptibility gene involved in the devolvement of the disease. The possible association between 9 selected polymorphisms in the NALP1/NLRP1 gene and AD was evaluated by comparing their frequency distribution in an Italian cohort of AD patients (AD, n = 276) and in a group of Italian sex-matched and age-matched healthy controls without dementia (HC, n = 266). Our study, evidences the association of 4 nonsynonymous polymorphisms in the NLRP1 gene (rs2137722, rs34733791, rs11657747, rs11651595) with AD. The major alleles of all 4 single nucleotide polymorphisms and the corresponding homozygote genotypes were more frequent in AD patients than in healthy controls, suggesting an association of these variants in the predisposition versus the development of the disease. These findings seem to support the previously reported role of NALP1 in neuronal damage, and provide evidence of an association between single nucleotide variations in the NLRP1 gene and AD
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
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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