1,722,479 research outputs found
HR 7250 ve HR 7545 yıldızlarının kimyasal bolluk analizi
No full textBu çalışmada, literatürde kapsamlı tayfsal bolluk analizi mevcut bulunmayan HR 7250 ve HR 7545 yıldızlarının kimyasal bolluk dağılımları incelendi. Yıldızların tayfları TÜBİTAK Ulusal Gözlemevi’nde RTT 150 Teleskobuna bağlı Coude Echelle tayfçekeri ile elde edildi. Her iki yıldızın yüksek çözünürlüklü tayfları 3920 - 9150 Å dalgaboyu aralığını kapsamaktadır. Gözlemsel verilerin indirgemeleri IRAF program ile gerçekleştirildi. BINMAG programı kullanılarak tayflarda yer alan soğurma çizgileri tanımlandı. Her çizgiye ait atomik tür, merkezi dalgaboyu ve eşdeğer genişlik değerleri ölçüldü. Atmosfer modelleri ATLAS9 (Kurucz 1993) kodu yardımıyla üretildi. Her iki yıldızın atmosfer parametreleri olan etkin sıcaklık, yüzey çekim ivmesi ve mikro türbülansları belirlendikten sonra ayrıntılı kimyasal bolluk analizi gerçekleştirildi. HR 7250 yıldızı için elde edilen değerler: Te = 8200 K, log g = 3.20 ve mikrotürbülans hızı 3.4 km sn-1’dır. Dönme hızı (v sini) 35 ± 5 km sn-1 olarak belirlendi. C, Mg, Si, Ca, Sc, Ti, Cr, Fe, Ni, Zn ve Ba elementlerinin bollukları hesaplandı. HR 7545 yıldızı için elde edilen değerler: Te = 8800 K, log g = 3.4 ve mikrotürbülans hızı 2.6 km sn-1 ’dır. Dönme hızı (v sini) ise 12 ± 3 km sn-1 olarak belirlendi. C, O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni, Zn, Sr, Y, Zr, ve Ba elementlerinin bollukları belirlendi.Kimyasal bolluk dağılımları göz önünde bulundurarak yıldızların kimyasal bakımda ne tür yıldızlar oldukları tartışıldı. Buna göre, HR 7545 yıldızında gözlenen bollukların Am türünden yıldızlara ilişkin bolluklarla, HR 7250 yıldızındakilerin ise normal A türünden yıldızlarda gözlenenlerle uyumlu olduğu bulundu. Yıldızlar için hesaplanan ışınım gücü ve etkin sıcaklık kullanılarak yıldızların HR diyagramı üzerindeki konumları belirlendi. Salasnich vd. (2000)evrim yolu modelleri kullanarak yıldızların kütleleri ve Bressan vd. (2012) izokronlar yardımıyla ise yaşları hesaplandı. HR 7250 yıldızının kütlesi 2.30 ± 0.09 Mʘ ve HR 7545 yıldızının ise 2.60 ± 0.09 Mʘ olarak hesaplandı. HR 7250 yıldızının yaşı 730 ± 60 milyon yıl ve HR 7545 yıldızının ise 560 ±40 milyon yıl olarak belirlendi. AbstractIn this study, the chemical abundance distribution of HR 7250 and HR 7545 was investigated. These two stars detailed abundance analysis are neglected in the literature. High resolution spectra covering 3920-9150Å of the optical spectral region were obtained with Coude Echelle Spectrograph attached to the RTT 150 telescope at the TÜBİTAK National Observatory. The echelle spectra reduction procedures were performed with IRAF. The spectral lines were measured using BINMAG. Atomic species, central wavelength, and equivalent width were determined for each spectral line. Model atmospheres were generated using the ATLAS9 code (Kurucz 1993). After the determination of the atmosphere parameters, which are effective temperature, surface gravity, and microturbulence, detailed chemical abundance analysis for both stars were performed. The adopted values of HR 7250 are Teff = 8200 K, log g = 3.2 and microturbulent velocity was calculated as 3.4 km s-1. Rotational velocity was measured as 35 ± 5 km s-1. The abundance of C, Mg, Si, Ca, Sc, Ti, Cr, Fe, Ni, Zn, and Ba were calculated for HR 7250. For HR 7545 the adopted values are Teff = 8800 K, log g = 3.4 and microturbulent velocity was calculated as 2.6 km s-1. Rotational velocity was measured as 12 ± 3 km s-1. C, O, Na, Mg, Al, Si, Ca, Sc, Ti, V, Cr, Mn, Fe, Ni, Zn, Sr, Y, Zr, and Ba abundances were calculated for HR 7545. These stars chemical distribution showed that HR 7545 is likely to be an Am star while HR 7250 is a normal A type star. The luminosity and effective temperatures of the stars pinpointed their positions on the HR diagram. The evolution tracks from Salasnich et al. (2000) and isochrones of Bressan et al. (2012) were also plotted on the HR diagram to determine the masses and ages of the stars. The mass was calculated as 2.30 ± 0.09 Mʘ for HR 7250 and 2.60 ± 0.09 Mʘ for HR 7545. The age of HR 7250 star was evaluated as 730 ± 60 million years and 560 ±40 million years for HR 7545
Linked collectors and determiners for: Artsprosjektet 43-15, Norway's hidden marine biodiversity: The hunt for cryptic species within the coralline algae.
No full textNatural history specimen data linked to collectors and determiners held within, "Artsprosjektet 43-15, Norway's hidden marine biodiversity: The hunt for cryptic species within the coralline algae". Claims or attributions were made on Bionomia by volunteer Scribes, <a href="http://bionomia.net/dataset/aef3c42a-7545-439e-bf29-9e0ff95f9ae0">https://bionomia.net/dataset/aef3c42a-7545-439e-bf29-9e0ff95f9ae0</a> using specimen data from the dataset aggregated by the Global Biodiversity Information Facility, <a href="https://gbif.org/dataset/aef3c42a-7545-439e-bf29-9e0ff95f9ae0">https://gbif.org/dataset/aef3c42a-7545-439e-bf29-9e0ff95f9ae0</a>. Formatted as a Frictionless Data package
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
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
Development of an interactive programming system for IBM 7545 robot
No full textThis thesis presents the development of an interactive programming system for the IBM 7545 robot. Various methods of robot programming are discussed, and the reasons for the development of such an interactive programming system are provided.
The development of this system was divided into five phases, namely, the development of the pseudo-compiler, development of the "system control" program, integration of ASSEMBLY routines, development of the "motion control" program, and the development of test programs. The approach used for each of these five stages are outlined, and a reference to the use of the system is given.
A description of the development of each stage is then given, and the logic associated with all programs are described, and the purpose and operation of all subroutines are also presented.
Some assumptions and limitations of the system are explained, and the operational aspects of the system are described. Additional work needed to improve this system is outlined, and the feasibility of using the concept of this system on other robot programming languages on the IBM 7545 robot are also discussed.M.S
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
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe 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
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