183,270 research outputs found
Vela brothers
No full textPhotograph shows a studio portrait of the Vela brothers."(L. to r." Nicolas Zambrano Vela; Federico Zambrano Vela; and Vicente Zambrano Vela, residents of Karnes County, Texas
Metaphase chromosomes of five Neotropical species of the genus Drosophila (Diptera, Drosophilidae)
No full textThe mitotic metaphases of five Andean species of genus Drosophila are described for the first time. The evolutionary and interspecific genetic relationships within three Neotropical Drosophila species groups are analyzed. The diploid chromosome number for each species is as follows: D. cashapamba Céspedes et Rafael, 2012 2n = 6 (2V, 1J) (X = J, Y = R), D. ecuatoriana Vela et Rafael, 2004 2n = 10 (3R, 2V) (X = V, Y = R), D. ninarumi Vela et Rafael, 2005 2n = 10 (3R, 1V, 1D) (X = V, Y = R), D. urcu Vela et Rafael, 2005 2n = 12 (4R, 2V) (X = V, Y = R), D. valenteae Llangarí-Arizo et Rafael, 2018 2n = 8 (3R, 1J) (X = J, Y = R)
Oral History Interview with Gerard Roland Vela, July 21, 2004
No full textInterview with Dr. Gerard Roland Vela, UNT Professor Emeritus of Microbiology. The interview includes Vela's personal experiences about childhood and education, serving in World War II-era U.S. Navy, having a fellowship at Harvard University, and joining the North Texas faculty in 1965. Additionally, Vela discusses his family history, his love of chemistry, genetics, and microbiology, the growing pains involved with transitioning North Texas into a research university, the construction of a research program, his relationship with students, and his service on the Denton City Council. Photographs are included throughout the interview
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Oral History Interview with Gerard Roland Vela, July 21, 2004
No full textInterview with Dr. Gerard Roland Vela, UNT Professor Emeritus of Microbiology. The interview includes Vela's personal experiences about childhood and education, serving in World War II-era U.S. Navy, having a fellowship at Harvard University, and joining the North Texas faculty in 1965. Additionally, Vela discusses his family history, his love of chemistry, genetics, and microbiology, the growing pains involved with transitioning North Texas into a research university, the construction of a research program, his relationship with students, and his service on the Denton City Council. Photographs are included throughout the interview
Two-component model for the interstellar scattering in direction to the Vela pulsar
No full textThis paper discusses a rigorous treatment of the refractive scintillation of pulsar PSR B0833-45 caused by a two-component interstellar scattering medium. It is assumed that the interstellar scattering medium is composed of a thin screen ISM and an extended interstellar medium. We consider that the scattering of the thin screen concentrates in a thin layer presented by a delta function distribution and that the scattering density of the extended irregular medium satisfies the Gaussian distribution. We investigate and develop equations for the flux density structure function corresponding to this two-component ISM geometry in the scattering density distribution and compare our result with that of the Vela pulsar observations. We conclude that the refractive scintillation caused by this two-component ISM scattering gives a more satisfactory explanation for the observed flux density variation of the Vela pulsar than does the single extended medium model. The level of refractive scintillation is strongly sensitive to the distribution of scattering material along the line of sight. The logarithmic slope of the structure function is sensitive to thin screen location and is relatively insensitive to the scattering strength of the thin screen medium. Therefore, the proposed model can be applied to interpret the structure function of flux density observed in pulsar PSR B0833-45. The result suggests that the medium consists of a discontinuous distribution of plasma turbulence embedded in the Vela supernova remnant. Thus our work provides some insight into the distribution of the scattering along the line of sight to the Vela pulsar.Astronomy & AstrophysicsSCI(E)EI3ARTICLE3909-91443
Behavioural Economics: Classical and Modern
No full textIn this paper, the origins and development of behavioural economics, beginning with the pioneering works of Herbert Simon (1953) and Ward Edwards (1954), is traced, described and (critically) discussed, in some detail. Two kinds of behavioural economics – classical and modern – are attributed, respectively, to the two pioneers. The mathematical foundations of classical behavioural economics is identified, largely, to be in the theory of computation and computational complexity; the corresponding mathematical basis for modern behavioural economics is, on the other hand, claimed to be a notion of subjective probability (at least at its origins in the works of Ward Edwards). The economic theories of behavior, challenging various aspects of 'orthodox' theory, were decisively influenced by these two mathematical underpinnings of the two theoriesClassical Behavioural Economics, Modern Behavioural Economics, Subjective Probability, Model of Computation, Computational Complexity. Subjective Expected Utility
Comments on an association in Vela
No full textEvidence for an association near the Vela pulsar rests on the H-R diagram. Definite bunching occurs around the mean line. However this evidence is not supported by correlation of proper motions in the region. If the Vela pulsar is a member of this association, a rather large mass is implied, about 10 solar masses
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
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A Search for r-Process Elements in the VELA Supernova Remnant
No full textAfter a description of recent developments in the physics of rapid neutron capture in Type II supernovae and a discussion of the detectability of supernovae ejecta, we present the data from a search for Ge, Kr, Yb, Os, and Hg in five stars behind or within the Vela remnant. Only Ge II was detected, but its column density and the upper limits of the other species show no excess above the estimated contribution of ambient gas. Finally, we discuss the extent that clumping and the improved performance of the GHRS may make r-process ejecta from Vela detectable in the future
Vela X at 31 GHz
No full textArtículo de publicación ISIWe present observations of the Vela X region at 31 GHz using the Cosmic Background Imager ( CBI). We find a strong compact radio source (5.'9 x 4.'1, FWHM) about the Vela pulsar, which we associate with the Vela pulsar wind nebula (PWN) recently discovered at lower radio frequencies. The CBI's 4' resolution for a 45' field of view allows the PWN to be studied in the large-scale context of Vela X. Filamentary structure in Vela X, which stands out in lower frequency maps, is very low level at 31 GHz. By combining the 10 CBI channels, which cover 26 36 GHz, and 8.4 GHz archive data, we study the spectral energy distribution ( SED) of the PWN and the brightest filaments. Our results show that the spectral index alpha (F(nu) proportional to nu(alpha)) of the PWN is flat, or even marginally positive, with a value of alpha(8.4)(31) = 0.10 +/- 0.06, while the Vela X filamentary structure has a negative spectral index of alpha(8.4)(31) = - 0.28 +/- 0.09. The SED inhomogeneity observed in Vela X suggests different excitation processes between the PWN and the filaments. We investigate whether the PWN's flat spectrum is a consequence of variability or truly reflects the SED of the object. We also investigate the nature of the Vela X filamentary structure. A faint filament crosses the PWN with its tangent sharing the same position angle as the PWN major axis, suggesting that it might be an extension of the PWN itself. The SED and bulk morphology of Vela X are similar to those of other well-studied plerions, suggesting that it might be powered by the pulsar. The peak of the PWN at 31 GHz is 80" +/- 20" southwest of the peak at 8.4 GHz. This shift is confirmed by comparing the 31 GHz CBI image with higher resolution 5 GHz Australia Telescope Compact Array observations and is likely to be due to SED variations within the PWN
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