1,720,965 research outputs found
Finite Element Analysis of Permeation Tests on Articular Cartilage underDifferent Testing Conditions Using COMSOL Multiphysics.
No full text
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
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
Optical mechanical and biochemical characterization of trabecular bone
No full textL’osso è un materiale complesso; cambiamenti in composizione e struttura dalla scala molecolare fino alla macro-scala. L’età e le condizioni patologiche modificano sia la composizione sia la struttura del materiale con ripercussioni sia sulla risposta ottica sia meccanica del materiale.
La patologia più diffusa è, senza dubbio, l’osteoporosi. A oggi, non esistono strumenti che permettono la diagnosi di questa patologia nelle prime fasi del suo sviluppo. Di conseguenza, la ricerca si sta muovendo verso lo sviluppo di nuove metodologie di diagnosi che siano in grado di individuare precocemente cambiamenti in composizione e struttura in maniera non invasiva.
L’obiettivo primario di questo studio è l’indagine delle correlazioni tra proprietà ottiche e comportamento meccanico del materiale su scale differenti (meso- e nano- scala, in particolare) per riuscire a individuare l’osteoporosi sul suo nascere. Inoltre, l’analisi delle proprietà ottiche dell’osso trabecolare è stata eseguita usando la spettroscopia per mezzi altamente diffondenti (DOS), tecnica già utilizzata per la diagnosi di patologie nei tessuti soffici.
Campioni di osso trabecolare umano (56 campioni da 12 pazienti sottoposti ad artroplastica dell’anca) e bovino (10 campioni da 5 animali sani) sono stati analizzati usando numerose tecniche. La risposta ottica è stata valutata usando la spettroscopia di Raman, DOS e μCT mentre le proprietà meccaniche sono state determinate con test alla mesoscala (prove di compressione non confinata), test alla nanoscala (prove di creep). Inoltre è stato implementato un semplice modello agli elementi finiti al fine di connettere le proprietà meccaniche alla meso- e alla nano- scala valutate sperimentalmente. Infine, il contenuto di collagene in ogni campione è stato definito valutando il contenuto d’idrossiprolina.
Tutti i risultati sono stati analizzati e confrontati al fine di individuare correlazioni tra i parametri che descrivono le varie tecniche, con particolare attenzione alle capacità della DOS nella definizione della composizione e struttura dell’osso in maniera non invasiva. Alcune delle correlazioni individuate erano già note in letteratura (ad esempio, le relazioni tra i parametri istomorfometrici da μCT e parametri meccanici) mentre altre sono del tutto nuove.
I valori di permeabilità sono correlati in maniera statisticamente significativa con il contenuto di collagene (R2=0.44 and p-value=0.02) e il rapporto tra idrossiapatite e collagene (R2=0.66 and p-value=0.001) valutato con la DOS.
Inoltre, il parametro a che descrive gli spettri di diffusione della DOS connesso alla densità della struttura è correlato con lo sforzo di snervamento (R2=0.59 and p-value=0.0035) e di rottura (R2=0.54 and p-value=0.0065).
In ultimo, la quantità di collagene individuati in maniera non invasiva con la DOS è stata confermata dall’analisi del contenuto d’idrossiprolina sui campioni idrolizzati.
In ultimo, questo studio aggiunge nuove informazioni in termini di proprietà ottiche del tessuto osseo ed è il primo passo per lo sviluppo di un sistema non invasivo capace di descrivere la struttura e la composizione dell’osso usando la spettroscopia per mezzi altamente diffondenti.Bone is a very complex and well-organized tissue; changes in composition and properties from molecular scale to organ level arise from the complexity of its structure. Age and pathological conditions influence bone response both mechanically and optically. The most common bone pathology is osteoporosis. Several treatments are available for osteoporosis, but no reliable methods are available to diagnose it at the early stage.
The research is moving towards the development of new techniques able to non-invasively assess the conditions of bone and to detect changes in composition and/or structure in the very early phase of the pathology development.
The knowledge of optic- mechanical correlation will be used to increase our understanding of the roles of components in the mechanical characteristics and to develop a non-invasive diagnostic tool for early detection of lesions and/or pathological conditions.
The present work aims at providing novel information about optic-structure- mechanical properties in bone, trabecular bone in particular, with a special goal to increase our knowledge of the roles of bone components in the mechanical characteristics of the tissue using information from diffuse optical spectroscopy (DOS), a non-invasive technique already successfully used to diagnose pathologies in soft tissues.
Human bone samples (56 samples from 12 patients who underwent arthoplasty of the hip) and bovine bone samples (10 samples from femurs of 5 healthy animals) were analyzed using several techniques. The optical properties were evaluated by Raman spectroscopy, DOS and μCT; the mechanical properties were determined by permeation tests, unconfined compression tests at the mesoscale and nanoindentaion tests. The mechanical behavior was further investigated by linking the mechanical properties at the nano-scale to those at the mesoscale through sample specific finite element models (FEM). Biochemical tests were finally performed to assess the collagen content in the tissue evaluating the hydroxyproline content
The results of the analyses were then compared, to determine correlations among experimental and computational methodologies, emphasizing the possibility of using DOS to detect mechanical and biochemical parameters.
If most of the determined correlations confirm known results from literature, some of them, like the relationship between the permeability and DOS spectra are novel.
Permeability values present a statistical significant correlation with composition, collagen amount (R2=0.44 and p-value=0.02) and collagen to hydroxyapatite ratio (R2=0.66 and p-value=0.001).
Such correlations confirm the possibility of using the DOS coefficient a, which describes the density of the structure, as an index of the mechanical features.; samples characterized by a high value of a present a better mechanical response i.e. high yield (R2=0.59 and p-value=0.0035) and ultimate stresses (R2=0.54 and p-value=0.0065).
DOS results were further confirmed by direct measurements of collagen estimated by hydroxyproline analyses. Mann-Whitney tests do not highlight differences between measurements of collagen content made using these two different techniques.
Therefore, this study is the first step in the elaboration of a new method to characterize bone tissue and opens the prospective of the development of a device that will permit a non-invasive analysis to early detect pathologies as osteoporosis.DIPARTIMENTO DI INGEGNERIA CIVILE E AMBIENTALE26PANDOLFI, ANNA MARINAPAOLUCCI, ROBERT
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