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197 results on '"Albayrak, B."'

1. Chemical abundances of the metal-poor horizontal-branch stars CS 22186-005 and CS 30344-033

Author

Caliskan, S., Caffau, E., Bonifacio, P., Christlieb, N., Monaco, L., Beers, T. C., Albayrak, B., and Sbordone, L.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

We report on a chemical-abundance analysis of two very metal-poor horizontal-branch stars in the Milky Way halo: CS 22186-005 ([Fe/H]=-2.70) and CS 30344-033 ([Fe/H]=-2.90). The analysis is based on high-resolution spectra obtained at ESO, with the spectrographs HARPS at the 3.6 m telescope, and UVES at the VLT. We adopted one-dimensional, plane-parallel model atmospheres assuming local thermodynamic equilibrium. We derived elemental abundances for 13 elements for CS 22186-005 and 14 elements for CS 30344-033. This study is the first abundance analysis of CS 30344-033. CS 22186-005 has been analyzed previously, but we report here the first measurement of nickel (Ni; Z = 28) for this star, based on twenty-two NiI lines ([Ni/Fe]=-0.21$\pm$0.02); the measurement is significantly below the mean found for most metal-poor stars. Differences of up to 0.5 dex in [Ni/Fe] ratios were determined by different authors for the same type of stars in the literature, which means that it is not yet possible to conclude that there is a real intrinsic scatter in the [Ni/Fe] ratios. For the other elements for which we obtained estimates, the abundance patterns in these two stars match the Galactic trends defined by giant and turnoff stars well. This confirms the value of horizontal-branch stars as tracers of the chemical properties of stellar populations in the Galaxy. Our radial velocities measurements for CS 22186-005 differ from previously published measurements by more than the expected statistical errors. More measurements of the radial velocity of this star are encouraged to confirm or refute its radial velocity variability.

Published
2014
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2. Physical Parameters of Some Close Binaries: ET Boo, V1123 Tau, V1191 Cyg, V1073 Cyg and V357 Peg

Author

Ekmekçi, F., Elmaslı, A., Yılmaz, M., Kılıçoğlu, T., Tanrıverdi, T., Baştürk, Ö., Şenavcı, H. V., Çalışkan, Ş., Albayrak, B., and Selam, S. O.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

With the aim of providing new and up-to-date absolute parameters of some close binary systems, new BVR CCD photometry was carried out at the Ankara University Observatory (AUG) for five eclipsing binaries, ET Boo, V1123 Tau, V1191 Cyg, V1073 Cyg and V357 Peg between April, 2007 and October, 2008. In this paper, we present the orbital solutions for these systems obtained by simultaneous light and radial velocity curve analyses. Extensive orbital solution and absolute parameters for ET Boo system were given for the first time through this study. According to the analyses, ET Boo is a detached binary while the parameters of four remaining systems are consistent with the nature of contact binaries. The evolutionary status of the components of these systems are also discussed by referring to their absolute parameters found in this study., Comment: this accepted paper will be published in New Astronomy

Published
2012
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3. A Spectroscopic Study of DD UMa: Ursa Major Group Member and Candidate for BRITE

Author

Elmaslı, A., Fossati, L., Folsom, C. P., Albayrak, B., and Izumiura, H.

Subjects
Astrophysics - Solar and Stellar Astrophysics
Abstract

The Ursa Major group is a nearby stellar supercluster which, while not gravitationally bound, is defined by co-moving members. DD UMa is a $\delta$ Scuti star whose membership in the Ursa Major group is unclear. The objective of this study is to confirm the membership of DD UMa in the Ursa Major group, as well as perform a detailed spectral analysis of the star. Since DD UMa is a low-amplitude $\delta$ Scuti star, we performed a frequency analysis. We determined fundamental parameters, chemical abundances, and derive a mass and age for the star. For this study we observed DD UMa at the Okayama Astrophysical Observatory with the high-resolution spectrograph HIDES, between the $27^{th}$ of February and the $4^{th}$ March, 2009. Additional observations were extracted from the ELODIE archive in order to expand our abundance analysis. Group membership of DD UMa was assessed by examining the velocity of the star in Galactic coordinates. Pulsational frequencies were determined by examining line profile variability in the HIDES spectra. Stellar fundamental parameters and chemical abundances were derived by fitting synthetic spectra to both the HIDES and ELODIE observations. DD UMa is found to be a member of the extended stream of the Ursa Major group, based on the space motion of the star. This is supported by the chemical abundances of the star being consistent with those of Ursa Major group members. The star is found to be chemically solar, with $T_{eff}=7450\pm150$ K and $\log g=3.98\pm0.2$. We found pulsational frequencies of 9.4 c/d and 15.0 c/d. While these frequencies are insufficient to perform an asteroseismic study, DD UMa is a good bright star candidate for future study by the BRITE-constellation., Comment: 6 pages, 4 figures

Published
2011
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4. A detailed spectropolarimetric analysis of the planet hosting star WASP-12

Author

Fossati, L., Bagnulo, S., Elmasli, A., Haswell, C. A., Holmes, S., Kochukhov, O., Shkolnik, E. L., Shulyak, D. V., Bohlender, D., Albayrak, B., Froning, C., and Hebb, L.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Earth and Planetary Astrophysics
Abstract

The knowledge of accurate stellar parameters is paramount in several fields of stellar astrophysics, particularly in the study of extrasolar planets, where often the star is the only visible component and therefore used to infer the planet's fundamental parameters. Another important aspect of the analysis of planetary systems is the stellar activity and the possible star-planet interaction. Here we present a self-consistent abundance analysis of the planet hosting star WASP-12 and a high-precision search for a structured stellar magnetic field on the basis of spectropolarimetric observations obtained with the ESPaDOnS spectropolarimeter. Our results show that the star does not have a structured magnetic field, and that the obtained fundamental parameters are in good agreement with what was previously published. In addition we derive improved constraints on the stellar age (1.0-2.65 Gyr), mass (1.23-1.49 M/M0), and distance (295-465 pc). WASP-12 is an ideal object to look for pollution signatures in the stellar atmosphere. We analyse the WASP-12 abundances as a function of the condensation temperature and compare them with those published by several other authors on planet hosting and non-planet hosting stars. We find hints of atmospheric pollution in WASP-12's photosphere, but are unable to reach firm conclusions with our present data. We conclude that a differential analysis based on WASP-12 twins will probably clarify if an atmospheric pollution is present, the nature of this pollution and its implications in the planet formation and evolution. We attempt also the direct detection of the circumstellar disk through infrared excess, but without success., Comment: 49 pages, 11 figures, Accepted for publication on ApJ

Published
2010
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9. The Period Variation of V839 Oph

Author

Şenavcı, H. V., Albayrak, B., Selam, S. O., Ak, T., Giménez, Àlvaro, editor, Guinan, Edward, editor, Niarchos, Panagiotis, editor, and Rucinski, Slavek, editor

Published
2006
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22. Development of A Measurement System for Weighing of Tuber Crops on A Conveyor Band

Author

Albayrak, B. and Bahattin Akdemir

Subjects
Bant kantarı, ağırlık ölçümü, precision agriculture, tuber crops, Belt scale, load cell, weight measurement, yük hücresi, yumru bitkileri, hassas tarım
Abstract

In this study, a specific design and manufacturing of a weight measurement system for tuber crops on a belt scale were conducted. The chassis of the belt scale was constructed by equal legs steel profile. The belt material was PVC. The rotational motion of the belt scale was obtained by an AC electric motor. The speed of the belt was measured by a tachometer. Several rollers were used to support the vertical loads on the belt. One of the rollers was connected directly to load cell to measure the weight of the tuber crops. In order to obtain the mass flow on the belt, the data of weight per unit meter from load cell and the speed data from tachometer were transmitted to an electronic board. Multiplication of these two data gives the unit mass flow rate of the tuber crops on the belt scale. The unit mass flow rate and total mass flow rate was displayed on an LCD display. The accuracy of this system was found to be between 96.4% - 97.5% during measurement of weight on a moving belt scale. Bu araştırmada, yumru bitkilerinin hareketli bir bant kantarı üzerinde ilerlerken ağırlıklarını anlık ve toplam olarak ölçen bir sistemin tasarımı ve üretimi yapılmıştır. Bant kantarının şasisi köşebent profilden imal edilmiştir. Sistemde PVC bant kullanılmış ve bandın dönüş hareketi bir elektrik motoru ile sağlanmıştır. Bant hızı bir takometre ile anlık olarak ölçülmüştür. Düşey yükleri taşımak için bant altında rulolar kullanılmıştır. Bu rulolardan biri ağırlık ölçmek için yük hücresine bağlanmıştır. Yük hücresinden gelen birim metredeki ağırlık bilgisi ile takometreden gelen hız bilgisi kullanılarak bir elektronik devre yardımı ile birim zamanda geçen yük miktarı hesaplanmıştır. Bu bilgiler LCD ekranda anlık olarak gösterilmiştir. Yapılan denemeler sonucunda %96.4 - %97.5 arasında doğruluk payıyla ağırlık hesabı yapılmıştır.

Published
2017

23. Organic Seed Production Of Lettuce (Lactuca Sativa L.) In Turkey

Author

Besirli, G., Sonmez, I., Albayrak, B., Polat, Z., and Tatar, I.

Abstract

Organic seed production needs intensive knowledge on both seed production and organic management system. This study was carried out to deliver organic lettuce seed production knowledge for seed companies and farmers. The experiments were performed during the spring and autumn seasons in an organic field at Ataturk Central Horticultural Research Institute (Yalova, Turkey) with ('Grise Maraichere') lettuce cultivar in 2013-2014. Yield, weight of 1000 seeds, number of seed g(-1) and germination rates were determined. The performance of the autumn growing season was better in terms of organic seed yield (185 kg ha(-1)) than the spring seed yield (115 kg ha(-1)). The results showed that 1000 seed weighed 1.02 g, and there were 1001 seeds in 1 g in autumn season. These properties were found as 0.91 g and 1048 seed, respectively in the spring season. The germination rate was found high in both seasons (90-100%). The major problems appeared as the fungal diseases. The main limitation was due to grey mould (Botrytis cinerea Pers.) for organic lettuce seed production in Yalova because of its rainy and highly humid climate condition.

Published
2017

26. Times of Minima of Some Eclipsing Binaries

Author

Bahar, E., primary, Yörükoglu, O., additional, Esmer, E. M., additional, Kilicoglu, T., additional, Öztürk, D., additional, Dogruel, M. B., additional, Özuyar, D., additional, Gümüs, D., additional, Izci, D. D., additional, Keten, B., additional, Tezcan, C. T., additional, Senavci, H. V., additional, Yilmaz, M., additional, Bastürk, Ö., additional, Selam, S. O., additional, Ekmekci, F., additional, Albayrak, B., additional, Caliskan, S., additional, and Akcar, A. E., additional

Published
2017
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31. Topical application of tacrolimus prevents epidural fibrosis in a rat postlaminectomy model: histopathological and ultrastructural analysis

Author

Gulsen, I, TANRIOVER, G, ISMAILOGLU, O, DEMIR, N, and ALBAYRAK, B

Subjects
Epidural Space, Male, Lumbar Vertebrae, Administration, Topical, Laminectomy, Fibroblasts, Fibrosis, Neurosurgical Procedures, Tacrolimus, Rats, Cicatrix, Disease Models, Animal, Microscopy, Electron, Postoperative Complications, Treatment Outcome, Cell Movement, Animals, Surgery, Neurology (clinical), Dura Mater, Failed Back Surgery Syndrome, Rats, Wistar, Spinal Canal, Immunosuppressive Agents
Abstract

Postlaminectomy epidural fibrosis is the formation of scar tissue over the dura mater following posterior spinal surgery. This devastating complication is responsible for the substantial amount of failed back syndromes. MATERIAL andTwenty male Wistar-Albino rats each weighing 350-400 grams were used. Following L3-L5 laminectomy, the rats were randomly divided into 2 groups, with 10 rats in each group. In the control group, only a laminectomy was performed. In the drug group, 5 mg/ml tacrolimus was topically applied with a cotton pad soaked with the drug solution for 5 minutes. The animals were killed on the 30th postoperative day injecting a lethal dose (250 mg/kg) of pentobarbital and the involved dural segments were removed for histopathological and ultrastructural evaluations.Epidural scar thickness and the density were significantly lower in the animals treated with tacrolimus than those of the control group.Promising evidence regarding the anti-scar potential of tacrolimus merits further research to optimize the dosage and the usage of the drug.

Published
2011

34. The Blazhko effect of RR lyrae in 2003-2004

Author

Kolenberg, K. Smith, H.A. Gazeas, K.D. Elmasli, A. Breger, M. Guggenberger, E. Van Cauteren, P. Lampens, P. Reegen, P. Niarchos, P.G. Albayrak, B. Selam, S.O. Özavci, I. Aksu, O.

Subjects
Astrophysics::Solar and Stellar Astrophysics
Abstract

Aims. Extensive photometry of RR Lyr was obtained over a 421-day interval in 2003-2004, covering more than 10 Blazhko cycles in a multisite campaign. The length and density of this data set allow for a detailed analysis. Methods. We used Fourier techniques to study RR Lyr's behavior over the pulsation and the Blazhko cycle. We propose a two-frequency model for decomposing the frequency spectrum. Results. The light variations were fitted with the main radial frequency, its harmonics up to 11th order, and the detected triplet frequencies. No significant quintuplet components were found in the frequency spectrum. Given the total time span of the measurements, we can now unambiguously conclude that the Blazhko period has become notably shorter than the previously known value of 40.8 days, whereas the main pulsation period remained roughly the same. Changes in the modulation period have been reported for other well-studied Blazhko variables. They challenge the explanations for the Blazhko effect which link the modulation period directly to the rotation period. The new photometry reveals an interval in the pulsation cycle of RR Lyr during which the star's intensity barely changes over the Blazhko cycle. This interval occurs during the infalling motion and between the supposed phases of the early and the main shock. The data also permit a more detailed study of the light curve shape at different phases in the Blazhko period through Fourier parameters. © ESO 2006.

Published
2006

42. Period variation of six RS CVn-type binaries with possible light-time effect

Author

Albayrak, B., Özeren, F. F., Fehmi Ekmekçi, and Demircan, O.

Subjects
Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics
Abstract

Long term period variation of six RS CVn type binaries (RT And, SV Cam, WY Cnc, CG Cyg, WW Dra, and RT Lac) formed by using the observed times of eclipse minima are presented and discussed with regard to the possible causes. The light-time effect due to invisible component stars was found to be the most possible cause. In all cases, the observed times of eclipse minima do not cover more than one complete cycle in the periodic (O-C) diagrams. Thus, the validity of the light-time effect is not definite for our sample stars, although the resulting orbital parameters and masses of the hypothetical third components are physically acceptable.

Published
1999

44. Transplantation - clinical studies II

Author

Marques, I. B., primary, Silva, R. d. M., additional, Moraes, C. E., additional, Azevedo, L. S., additional, Nahas, W. C., additional, David-Neto, E., additional, Furmanczyk-Zawiska, A., additional, Baczkowska, T., additional, Chmura, A., additional, Szmidt, J., additional, Durlik, M., additional, Joslin, J., additional, Blaker, P., additional, White, B., additional, Marinaki, A., additional, Sanderson, J., additional, Goldsmith, D. J., additional, Medani, S., additional, Traynor, C., additional, Mohan, P., additional, Little, D., additional, Conlon, P., additional, Molina, M., additional, Gonzalez, E., additional, Gutierrez, E., additional, Sevillano, A., additional, Polanco, N., additional, Morales, E., additional, Hernandez, A., additional, Praga, M., additional, Morales, J. M., additional, Andres, A., additional, Park, S. J., additional, Kim, T. H., additional, Kim, Y. W., additional, Kim, Y. H., additional, Kang, S. W., additional, Kujawa-Szewieczek, A., additional, Szotowska, M., additional, Kuczera, P., additional, Chudek, J., additional, Wiecek, A., additional, Kolonko, A., additional, Mahrova, A., additional, Svagrova, K., additional, Bunc, V., additional, Stollova, M., additional, Teplan, V., additional, Hundt, F., additional, van Heteren, P., additional, Woitas, R., additional, Cavallo, M. C., additional, Sepe, V., additional, Conte, F., additional, Albrizio, P., additional, Bottazzi, A., additional, Geraci, P. M., additional, Alpay, N., additional, Gumber, M. R., additional, Kute, V. B., additional, Vanikar, A. V., additional, Patel, H. V., additional, Shah, P. R., additional, Engineer, D. P., additional, Trivedi, H. L., additional, Golebiewska, J. E., additional, Debska-Slizien, A., additional, Rutkowski, B., additional, Matias, P., additional, Martins, A. R., additional, Raposo, L., additional, Jorge, C., additional, Weigert, A., additional, Birne, R., additional, Bruges, M., additional, Adragao, T., additional, Almeida, M., additional, Mendes, M., additional, Machado, D., additional, Masin-Spasovska, J., additional, Dohcev, S., additional, Stankov, O., additional, Stavridis, S., additional, Saidi, S., additional, Dejanova, B., additional, Rambabova-Busletic, I., additional, Dejanov, P., additional, Spasovski, G., additional, Nho, K. W., additional, Han, D. J., additional, Park, S.-K., additional, Kim, S. B., additional, Fenoglio, R., additional, Lazzarich, E. E., additional, Cagna, D., additional, Cena, T., additional, Conti, N., additional, Quaglia, M., additional, Radin, E., additional, Izzo, C., additional, Stratta, P., additional, Oh, I. H., additional, Park, J.-S., additional, Lee, C. H., additional, Kang, C. M., additional, Kim, G.-H., additional, Leone, F., additional, Lofaro, D., additional, Gigliotti, P., additional, Lupinacci, S., additional, Toteda, P., additional, Vizza, D., additional, Perri, A., additional, Papalia, T., additional, Bonofiglio, R., additional, di Loreto, P., additional, de Silvestro, L., additional, Montanaro, D., additional, Martino, F., additional, Sandrini, S., additional, Minetti, E., additional, Cabiddu, G., additional, Yildirim, T., additional, Yilmaz, R., additional, Turkmen, E., additional, Abudalal, A., additional, Altindal, M., additional, Ertoy-Baydar, D., additional, Erdem, Y., additional, Panuccio, V., additional, Tripepi, R., additional, Parlongo, G., additional, Versace, M. C., additional, Politi, R., additional, Zoccali, C., additional, Mallamaci, F., additional, Porrini, E., additional, Silva, I., additional, Diaz, J., additional, Ibernon, M., additional, Moreso, F., additional, Benitez, R., additional, Delgado Mallen, P., additional, Osorio, J., additional, Lauzurica, R., additional, Torres, A., additional, Ersoy, A., additional, Koca, N., additional, Gullu Koca, T., additional, Kirhan, E., additional, Sarandol, E., additional, Ersoy, C., additional, Dirican, M., additional, Milne, J., additional, Suter, V., additional, Mikhail, A., additional, Akalin, H., additional, Dizdar, O., additional, Pascual, J., additional, Torio, A., additional, Garcia, C., additional, Hernandez, J., additional, Perez-Saez, M. J., additional, Mir, M., additional, Anna, F., additional, Crespo, M., additional, Carta, P., additional, Zanazzi, M., additional, Antognoli, G., additional, Di Maria, L., additional, Caroti, L., additional, Ray, D. S., additional, Mukherjee, K., additional, Bohidar, N. P., additional, Pattanaik, A., additional, Das, P., additional, Thukral, S., additional, Kimura, T., additional, Yagisawa, T., additional, Ishikawa, N., additional, Sakuma, Y., additional, Fujiwara, T., additional, Nukui, A., additional, Gavela, E. E., additional, Sancho, A. A., additional, Kanter, J. J., additional, Avila, A. A., additional, Beltran, S. S., additional, Pallardo, L. L., additional, Dawoud, F. G., additional, Aithal, V., additional, Majernikova, M., additional, Rosenberger, J., additional, Prihodova, L., additional, Nagyova, I., additional, Jarcuskova, M., additional, Roland, R., additional, Groothoff, J. W., additional, van Dijk, J. P., additional, van Agteren, M., additional, de Weerd, A., additional, van de Wetering, J., additional, IJzermans, J., additional, Betjes, M., additional, Weimar, W., additional, Popoola, J., additional, Reed, A., additional, Tavarro, R., additional, Chryssanthopoulou, C., additional, MacPhee, I., additional, Mayor, M., additional, Franco, S., additional, Jara, P., additional, Ayala, R., additional, Orue, M. G., additional, Martinez, A., additional, Martinez, M., additional, Wasmouth, N., additional, Arik, G., additional, Yasar, A., additional, Yilmaz, S., additional, Arici, M., additional, Bihari Bansal, S., additional, Pokhariyal, S., additional, Jain, S., additional, Sethi, S., additional, Ahlawat, R., additional, Kher, V., additional, Martins, L. S., additional, Aguiar, P., additional, Dias, L., additional, Fonseca, I., additional, Henriques, A. C., additional, Cabrita, A., additional, Davide, J., additional, Sparkes, T. M., additional, Trofe-Clark, J., additional, Reese, P. P., additional, Jakobowski, D., additional, Goral, S., additional, Doll, S. L., additional, Abt, P. L., additional, Sawinski, D., additional, MBloom, R. D., additional, Knap, B., additional, Lukac, J., additional, Lukin, M., additional, Majcen, I., additional, Pavlovec, F., additional, Kandus, A., additional, Bren, A. F., additional, Kong, J. M., additional, Jeong, J. H., additional, Ahn, J., additional, Lee, D. R., additional, Son, S. H., additional, Kim, B. C., additional, Choi, W. Y., additional, Whang, E. J., additional, Czajka, B., additional, Malgorzewicz, S., additional, Panizo, N., additional, Rengel, M. A., additional, Vega, A., additional, Abad, S., additional, Tana, L., additional, Arroyo, D., additional, Rodriguez-Ferrero, M., additional, Perez de Jose, A., additional, Lopez-Gomez, J. M., additional, Koutroutsos, K., additional, Sackey, J., additional, Paolini, L., additional, Ramkhelawon, R., additional, Chowrimootoo, M., additional, Whelan, D., additional, Slatinska, J., additional, Honsova, E., additional, Wohlfahrtova, M., additional, Slimackova, E., additional, Rajnochova, S. B., additional, Viklicky, O., additional, Yankovoy, A., additional, Smith, I. S. J., additional, Wylie, E., additional, Ruiz-Esteban, P., additional, Lopez, V., additional, Garcia-Frias, P., additional, Cabello, M., additional, Gonzalez-Molina, M., additional, Vozmediano, C., additional, Hernandez, D., additional, Pavlovic, J., additional, Radivojevic, D., additional, Lezaic, V., additional, Simic-Ogrizovic, S., additional, Lausevic, M., additional, Naumovic, R., additional, Sakhuja, V., additional, Gundlapalli, S., additional, Rathi, M., additional, Jha, V., additional, Kohli, H. S., additional, Sharma, A., additional, Minz, M., additional, Nimgirova, A., additional, Esayan, A., additional, Kayukov, I., additional, Zuyeva, E., additional, Bilen, Y., additional, Cankaya, E., additional, Keles, M., additional, Gulcan, E., additional, Turkeli, M., additional, Albayrak, B., additional, Uyanik, A., additional, Yildirim, R., additional, Molitor, N., additional, Praktiknjo, M., additional, Abeygunaratne, T. N., additional, Balasubramanian, S., additional, Baker, R., additional, Nicholson, T., additional, Toprak, O., additional, Sari, Y., additional, Keceli, S., additional, Kurt, H., additional, Rocha, A., additional, Malheiro, J., additional, Pedroso, S., additional, Henriques, A., additional, Nihei, C., additional, Bacelar Marques, I., additional, Seguro, C. A., additional, Mate, G., additional, Martin, N., additional, Colon, L., additional, Casellas, L., additional, Garangou, D., additional, de la Torre, M., additional, Torguet, P., additional, Garcia, I., additional, Calabia, J., additional, Valles, M., additional, Pruthi, R., additional, Calestani, M., additional, Leydon, G., additional, Ravanan, R., additional, Roderick, P., additional, Korkmaz, S., additional, and Gulten, S., additional

Published
2013
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