1,720,954 research outputs found
Physics of Fluids
No full textThe scope of this book is to provide readers having a knowledge of calculus and
Physics at the college level with an introduction to physics of fluids.
That of fluid is one of the various states of matter, the most common in nature
both on the Earth and in the astronomical context.
Fluids, which include liquids, gases and plasmas, are essential for life: the air we
breathe is a gas, the atmosphere which shields us from harmful radiations is a gas
mixture, the water we drink and feeds plants is a liquid, and the salted water of seas
and oceans is a liquid. So, a basic knowledge of the behavior of gases and liquids
should actually constitute a natural value for everyone’s culture. Such a knowledge
might be helpful, for instance, in distinguishing better what is true and what is false
among the many assessments that are commonly stated about things like global
warming, greenhouse effect, ice retreat and so on.
I wrote this book with the aim of coupling rigor in mathematical developments to
a clear and intuitive representation of the various phenomena characterizing the often
very complicated behavior of fluids in nature, in terrestrial as well as in astronomical
environments. I tried to do this in a short volume which can be easily understood
and handled. I proposed also a few developed exercises which should be helpful in a better understanding of the topic
Classical newtonian gravity
No full textThis book gives an introduction to classical Newtonian gravitation and potential
theories, as pieces of Physics essential for understanding classical mechanics and
particularly relevant for Astrophysics. Among the four fundamental forces of
Physics, gravity has the unique aspect of being an unscreened force which permeates
the whole universe. Moreover, although Einstein’s general relativity provides a more
extended framework for gravity, for most of the practical purposes, both in the field
of pure scientific investigation and in the applicative one, Newtonian gravity
provides much simpler and sufficiently approximated results, whenever applied in
the regime of weak field.
To reach the aim, the book is structured as follows.
In the first chapter, some essential elements of vectorial calculus are recalled,
especially to provide the formalism used in the following chapters.
In the second chapter, classical Newtonian gravity theory for one and a generic
number N of point masses is presented and discussed. The theory for point masses
is naturally extended to the continuous case in the same chapter.
In the third chapter, the paradigmatic case of spherical symmetry in the mass
density distribution (central force) is dealt with the introduction of the useful tool of
qualitative treatment of motion.
In chapter four, the general case of nonsymmetric mass density distribution is
discussed. In this chapter, classical potential theory is presented, with elements of
harmonic theory, which is essential to understand the series development of the
potential development in the discussed in the second part of the chapter.
The short, final, chapter five deals with the specific case of the motion of a
satellite around the Earth.
Examples and exercises are presented throughout the book to clarify aspects
of the theory
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
Author-wise bibliometric analysis based on entropy.
No full textAuthor-wise bibliometric analysis based on entropy.</p
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