86,902 research outputs found
The evolution of the milky way from its earliest phases: constraints on stellar nucleosynthesis
No full textWe computed the evolution of the abundances of O, Mg, Si, Ca, K, Ti, Sc, Ni, Mn, Co, Fe and Zn in the Milky Way. We made use of the most widely adopted nucleosynthesis calculations and compared the model results with observational data with the aim of imposing constraints upon stellar yields. To best fit the data in the solar neighborhood, when adopting the Woosley & Weaver (1995, ApJS, 101, 181) yields for massive stars and the Iwamoto et al. (\cite{Iwamoto99}, ApJS, 125, 439) ones for type Ia SNe, it is required that: i) the Mg yields should be increased in stars with masses from 11 to 20 Msun and decreased in masses larger than 20 Msun. The Mg yield should be also increased in SNe Ia. ii) The Si yields should be slightly increased in stars above 40 Msun, whereas those of Ti should be increased between 11 and 20 Msun and above 30 Msun. iii) The Cr and Mn yields should be increased in stars with masses in the range 11-20 Msun; iv) the Co yields in SNe Ia should be larger and smaller in stars in the range 11-20 Msun; v) the Ni yield from type Ia SNe should be decreased; vi) the Zn yield from type Ia SNe should be increased. vii) The yields of O (metallicity dependent SN models), Ca, Fe, Ni, and Zn (the solar abundance case) in massive stars from Woosley & Weaver (\cite{Woosley95}) are the best to fit the abundance patterns of these elements since they do not need any changes. We also adopted the yields by Nomoto et al. (\cite{Nomoto97}, Nucl. Phys. A, 621, 467) and Limongi & Chieffi (\cite{Limongi03}, ApJ, 592, 404) for massive stars and discuss the corrections required in these yields in order to fit the observations. Finally, the small spread in the [el/Fe] ratios in the metallicity range from [Fe/H] = -4.0 up to -3.0 dex (Cayrel et al. \cite{Cayrel03}, A&A, 416, 1117) is a clear sign that the halo of the Milky Way was well mixed even in the earliest phases of its evolution
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
New laboratory lifetime measurements of U II for the uranium cosmochronometer
No full textWe present new measurements of radiative lifetimes for six energy levelsof singly ionized uranium, U II, using laser-induced fluorescencetechnique. One of the levels,5f36d7p6M13/2 at 26191 cm-1,decays by a transition at 3859.6 Å. This line has recently beenobserved in the spectrum of the metal-poor star CS1082-001, the firstdetection of uranium outside the solar system. The lambda 3859 line canbe used as the presently most accurate cosmochronometer (Cayrel et al.cite{Cayrel}). Our value of the lifetime of the6M13/2 level is 18.6+/-0.7 ns, and it confirms thef-value used in the Nature article by Cayrel et al. (cite{Cayrel}),which is based on an experimental lifetime of 20+/-5 ns (Chen &Borzileri cite{Chen}). The new measurement also removes the doubt aboutthe choice between that value and other f-values in the literature,differing by a factor of 3. Adopting the same branching fraction as Chen& Borzileri (cite{Chen}) for the 3859.6 Å line, we derive agf-value of 0.68, which is 8% higher than the value used by Cayrel etal. (cite{Cayrel}). Of significance for the chronometer is also thereduced uncertainty of the radiative lifetime, 4% compared to 25%, andconsequently of the f-value, which should decrease the uncertainty inthe determination of the stellar age considerably
[Newspaper Clipping: Author Claims Evidence of Second JFK Assassin #1]
No full textNewspaper article titled "Author Claims Evidence of Second JFK Assassin." The article states that author Richard J. Whalen concluded "that there is circumstantial evidence to support the theory of a second assassin in the shooting of President John F. Kennedy.
Also By The Same Author: AKTiveAuthor, a Citation Graph Approach to Name Disambiguation
No full textThe desire for definitive data and the semantic web drive for inference over heterogeneous data sources requires co-reference resolution to be performed on those data. In particular, name disambiguation is required to allow accurate publication lists, citation counts and impact measures to be determined. This paper describes a graph-based approach to author disambiguation on large-scale citation networks. Using self-citation, co-authorship and document source analyses, AKTiveAuthor clusters papers, achieving precision of 0.997 and recall of 0.818 over a test group of eight surname clusters
John F. Kennedy telegram to Roosevelt
No full textJersey Homesteads (later the Borough of Roosevelt) was established in the 1930s as an agro-industrial cooperative community. It was established specifically for urban Jewish garment workers, many of whom had emigrated from Europe. President John F. Kennedy sent a telegram to the citizens of Roosevelt, New Jersey, apologizing for not being able to attend the memorial dedication in honor of former President Franklin Delano Roosevelt. (Jersey Homesteads became Roosevelt in 1945 in honor of the president.) President Kennedy expressed his gratitude to the people of Roosevelt for constructing the memorial, and commented that it will serve as a constant reminder of Roosevelt's good works
Logarithmic variance profiles and the corresponding f-1 spectra of temperature fluctuations in turbulent Rayleigh-Bénard convection
No full textWe report experimental results for the temperature variance 2(z) and the corresponding frequency spectra P(f) in turbulent Rayleigh-Bénard convection (RBC) in a cylindrical sample of aspect ratioT= D/L = 1:00 (D = 1:12 m is the diameter and L = 1:12 m the height). The measurements were conducted in the Rayleigh-number range 1011 < Ra < 1:35 1014 and Pr ' 0:8. For Ra = 1:35x1014, 2(z) could be described well by a logarithmic dependence on the vertical position z in a range of z 1 < z < z 2 with z 1 ' 70 and z 2 = 0:1L. Here L=(2Nu) is the thickness of a thin thermal sublayer adjacent to the horizontal plate where the heat flux (denoted by the Nusselt number Nu) is carried mostly by thermal diffusion. In the log layer, we found that the temperature spectra had a significant frequency range over which P(f) f with close to 1. As Ra decreased, increased so that the log layer became thinner. At Ra = 2:05 1011, z 2 < z 1 and therefore there was no range for a log layer. Correspondingly, the temperature spectrum near the horizontal plate did not have the f1 scaling form either
Maine author Franklin F. Gould recalls his first glimpse of the outside world
No full textMaine author Franklin F. Gould recalls his first glimpse of the outside world as he relates how, as a young farm boy in the late 1800\u27s, he drove his father\u27s horses on an errand to an icebound river
The PASTEL catalogue (Soubiran+, 2010)
No full textpastel.dat 30151x202 The catalogue of stellar atmospheric parametersVizieR On-line Data Catalog: B/pastel. Originally published in: 2010A&A...515A.111SPASTEL is a bibliographical catalogue compiling determinations of stellar atmospheric parameters. It provides (Teff, logg, [Fe/H]) determinations obtained from detailed analyses of high resolution, high signal to noise spectra, carried out with the help of model atmospheres. It also provides effective temperatures Teff from various methods. PASTEL is regularly updated. The catalogue supersedes the two previous versions of the [Fe/H] catalogue (Cayrel de Strobel et al., 1997 [Cat. III/200], 2001 [Cat. III/221]). (1 data file)
- …
