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Performance of fly visual interneurons during object fixation
Get PDFKimmerle B, Egelhaaf M. Performance of fly visual interneurons during object fixation. The journal of neuroscience. 2000;20(16):6256-6266
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe 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
Colour-magnitude diagrams of the post-core collapse globular clusters NGC 6256 and NGC 6717 (Palomar 9)
No full textWe present photometry of the
globular clusters NGC 6256 in V, I,
NGC 6717, NGC 6256 in V, I, and NGC 6717 in B, V,
obtaining cluster parameters.
NGC 6256 has a post core-collapse structure,
while such feature is suspected for NGC 6717.
Both clusters are projected on the bulge.
From the colour-magnitude
diagrams for NGC 6256 we derive reliable cluster parameters
which
considerably revise its properties, with respect
to previous literature. It
has a blue-extended Horizontal Branch
already observed in other post-core
collapse clusters in the bulge, such as HP1.
We derive a reddening of , a distance
kpc,
and an intermediate metallicity for NGC 6256.
NGC 6717 presents a blue Horizontal Branch.
We derive a reddening of and a distance kpc, locating the cluster in
the bulge. The photometry is deep and
we study the luminosity function, which presents some evidence of
depletion of Main Sequence stars. This effect is not unexpected for
such a poorly populated Palomar cluster in the bulge.
We also estimate the cluster age
from the magnitude difference between the horizontal branch and the
turnoff. We obtain , which would place
this intermediate metallicity bulge globular as coeval with the halo
Variations on the Author
Get PDF“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
Get PDFWe 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
Digging for Relics of the Past: The Ancient and Obscured Bulge Globular Cluster NGC 6256
Get PDFWe used a set of moderately deep and high-resolution optical observations obtained with the Hubble Space Telescope to investigate the properties of the stellar population in the heavily obscured bulge globular cluster (GC) NGC 6256. The analysis of the color–magnitude diagram (CMD) revealed a stellar population with an extended blue horizontal branch severely affected by differential reddening, which was corrected, taking into account color excess variations up to δE(B − V) ~ 0.51. We implemented a Monte Carlo Markov Chain technique to perform the isochrone fitting of the observed CMD in order to derive the stellar age, the cluster distance, and the average color excess in the cluster direction. Using three different sets of isochrones we found that NGC 6256 is characterized by a very old stellar age around 13.0 Gyr, with a typical uncertainty of ~0.5 Gyr. We also found an average color excess of E(B − V) = 1.19 and a distance from the Sun of 6.8 kpc. We then derived the cluster gravitational center and measured its absolute proper motion using the Gaia-DR2 catalog. All this was used to back-integrate the cluster orbit in a Galaxy-like potential and measure its integrals of motion. It turned out that NGC 6256 is currently in a low-eccentricity orbit entirely confined within the bulge and its integrals of motion are fully compatible with a cluster purely belonging to the Galaxy native GC population. All these pieces of evidence suggest that NGC 6256 is an extremely old relic of the past history of the Galaxy, formed during the very first stages of its assembly
Radio localization of IGR J16597-3704, a candidate neutron star X-ray binary undergoing an outburst in NGC 6256
Get PDFWe report follow-up VLA radio observations of NGC 6256, the globular cluster hosting the newly detected X-ray transient IGR J16597-3704 (ATel #10880, #10881)
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