1,721,492 research outputs found
Betrachtungen über den Zustand der deutschen Pharmacie : eine Gratulationsschrift zur Jubelfeier funfzigjähriger pharmaceutischer Wirksamkeit und fünfundzwanzigjähriger Amtsführung als Oberdirector des Apotheker-Vereins in Norddeutschland, L. F. Bley gewidmet
No full textvon T. Geiseler ; C. Herzog u. Wilm
Taxis of Artificial Swimmers in a Spatio-Temporally Modulated Activation Medium
No full textContrary to microbial taxis, where a tactic response to external stimuli
is controlled by complex chemical pathways acting like sensor-actuator
loops, taxis of artificial microswimmers is a purely stochastic effect
associated with a non-uniform activation of the particles'
self-propulsion. We study the tactic response of such swimmers in a
spatio-temporally modulated activating medium by means of both numerical
and analytical techniques. In the opposite limits of very fast and very
slow rotational particle dynamics, we obtain analytic approximations
that closely reproduce the numerical description. A swimmer drifts on
average either parallel or anti-parallel to the propagation direction of
the activating pulses, depending on their speed and width. The drift in
line with the pulses is solely determined by the finite persistence
length of the active Brownian motion performed by the swimmer, whereas
the drift in the opposite direction results from the combination of the
ballistic and diffusive properties of the swimmer's dynamics
Self-Polarizing Microswimmers in Active Density Waves
No full textAn artificial microswimmer drifts in response to spatio-temporal
modulations of an activating suspension medium. We consider two
competing mechanisms capable of influencing its tactic response: angular
fluctuations, which help it explore its surroundings and thus diffuse
faster toward more active regions, and self-polarization, a mechanism
inherent to self-propulsion, which tends to orient the swimmer's
velocity parallel or antiparallel to the local activation gradients. We
investigate, both numerically and analytically, the combined action of
such two mechanisms. By determining their relative magnitude, we
characterize the selective transport of artificial microswimmers in
inhomogeneous activating media
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe 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
No full text“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
No full textWe 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
No full textWe 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
Ten key messages of the S2k guideline on noninvasive mechanical ventilation in acute respiratory failure
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