1,721,558 research outputs found
Ritratto di un antipapa: Amedeo VIII di Savoia (Felice V) negli scritti di Enea Silvio Piccolomini
No full textIl contributo delinea il profilo dell'antipapa Felice V attraverso gli scritti di Enea Silvio Piccolomin
Low energy electron and positron measurements in space with the PAMELA experiment
Full text linkQuesta tesi descrive lo studio di elettroni e positroni nella radiazione cosmica. Nuove misure della frazione di positroni al top dell’atmosfera tra 200 MeV e 3.0 GeV, nonché lo spettro di elettroni fino a 20 GeV, sono presentati. La misura è stata effettuata con l’esperimento PAMELA da Luglio 2006 a Dicembre 2008, periodo di minima attività solare e polarità negativa. PAMELA fornisce le prime osservazioni a lungo termine della frazione di positroni di bassa energia durante questo particolare stato della eliosfera. La grande statistica collezionata permette di studiare la variazione del flusso di particelle a Terra in funzione dell’energia e del tempo, e di investigare effetti dipendenti dal segno della carica. Durante circa 860 giorni di raccolta dati circa 16000 positroni e 178000 elettroni sono stati identificati. Le maggiore fonte di fondo, costituite da protoni e pioni localmente prodotti, sono state studiate. Lo spettro di elettroni derivato mostra chiaramente l’effetto della modulazione solare sotto qualche GeV. La frazione di positroni è risultata in accordo con le predizioni di modelli teorici che descrivono il trasporto di particelle nell’eliosfera che tengono conto di effetti di drift.This thesis describes the study of electrons and positrons in the cosmic radiation. New
measurements of the positron fraction at the top of the atmosphere between 200 MeV and
3.0 GeV are presented, together with the electron spectrum up to 20 GeV. The measurement
was conducted with the space borne PAMELA experiment from July 2006 to December
2008, that is a period of minimum solar activity and negative solar magnetic field
polarity. PAMELA provides the first long term observation of the low energy positron
abundance during this particular solar and heliospheric state. The great amount of collected
statistics allows to study the variation of the particle intensity at Earth with energy
and time, and to investigate effects depending on the particles sign of charge. During approximately
860 days of data collection about 16300 positrons and 178000 electrons were
identified. The major sources of background, constituted by cosmic protons and locally
produced pions, have been studied. The derived electron spectrum clearly shows the effect
of the solar modulation below few GeV. The detected positron fraction has been found to
be in accordance with predictions from theoretical models that describe the transport of
particles in the heliosphere taking drift effects into account
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
Editorial: Myokines, Adipokines, Cytokines in Muscle Pathophysiology.
Full text link[No abstract available
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
Extracellular Vesicles: delivery vehicles of myokines
Full text linkMovement and regular physical activity are two important factors that help human body prevent, reduce and treat different chronic diseases such as obesity, type 2 diabetes, heart diseases, hypertension, sarcopenia, cachexia and cancer.
During exercise, several tissues release molecules into the blood stream, able to mediate beneficial effects throughout the whole body. In particular, contracting skeletal muscle cells have the capacity to communicate with other organs trough the release of humoral factors that play an important role in the mechanisms of adaptation to physical exercise. These muscle-derived factors, today recognised as myokines act as endocrine and paracrine hormones.
Moreover, exercise may stimulate the release of small membranous vesicles into circulation, whose composition is influenced by the same exercise. Combining the two hypothesis, these molecules related to exercise, named also exer-kines, might be secreted from muscle cells inside small vesicles (nanovesicles). These could act as messengers in tissue cross talk during physical exercise. Thanks to their ability to deliver useful molecules (such as proteins and miRNA), in both physiological and pathological conditions, extracellular vesicles can be thought as promising candidates for potential therapeutic and diagnostic applications for several diseases
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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