3,914 research outputs found

    ROTSE observations of the young cluster IC 348

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    CCD observations of stars in the young cluster IC 348 were obtained from 2004 August to 2005 January with a 0.45 m ROTSEIIId robotic reflecting telescope at the Turkish National Observatory site, Bakirlitepe, Turkey. The timing analysis of selected stars whose X-Ray counterpart were detected by Chandra X-Ray Observatory were studied. The time series of stars were searched for rotational periodicity by using different period search methods. 35 stars were found to be periodic with periods ranging from 0.74 to 32.3 days. Eighteen of the 35 periodic stars were new detections. Four of the new detections were CTTSs and the others were WTTSs and G type (or unknown spectral class) stars. In this study, we confirmed the stability of rotation periods of TTauri stars. The periods obtained by Cohen et al. and us were different by 1%. We also confirmed the 3.24 h pulsation period of H254 which is a delta Scuti type star as noted by Ripepi et al. but the other periods detected by them were not found. We examined correlation between X-ray luminosity and rotational period of our sample of TTSs. There is a decline in the rotational period with X-ray luminosity for late type TTSs.Comment: 15 pages, 14 figures, accepted for publication in Astronomical Journa

    Some Effects of Copper Sulfate, Copper Oxide and 4-Nitrophenylarsonic Acid on Aortic Rupture and Growth of Turkeys

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    Previous studies have shown that adding copper, as copper sulfate, to raise the copper level to 120 ppm in low and high protein diets resulted in Increased weight gains and reduced incidence of aortic ruptures. Without copper additives the diets contain 8 to 12 ppm Cu. In all previous studies, 4-nitrophenylarsonic acid was used as a blackhead preventative. It is acknowledged that 4-nitro depressed growth. Also sulfate ions, from various sources, have shown a sparing effect on the sulfur amino acids, thereby promoting growth. These facts raised several questions. Does the added copper promote growth by suppressing toxicity of 4-nitro or by adding sulfate ions to the diet? Also, does the added copper increase the amount of copper stored in the liver

    Turkey Performance as Influenced by Egg Dipping

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    This experiment has not been completed. The data shown were obtained at 12 weeks. Eggs from a breeder flock with a known history of Mycoplasma gallisepticum infection were dipped in a solution containing a combination of 2800 ppm Tylan and 2000 ppm Neomycin before incubation. The eggs were first dipped in warm water (98┬░F) for 5 minutes and then into the cold (38┬░F) antibiotic solution for 10 minutes. Batches of 50 eggs increased in weight 6 to 18 grams from this treatment, thus showing an average uptake of 0.68 mcg of tylosin and 0.49 mcg of Neomycin of the eggs were 3 weeks old when set and the balance 1 week. Therefore, the old and young eggs were set separately. Results would indicate that the age of the eggs and dipping affected 7-day fertility and hatchability. Last year the eggs were dipped using a vacuum method

    Some Effects of Copper and High and Low Protein Diets on Aortic Rupture and Growth of Turkets

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    In other studies using high and low protein diets for growing turkeys, aortic ruptures frequently caused high death losses, particularly among the large type males. Inadequate elastin formation and the resulting lack of strength and elastic ity may be contributing factors in aortic failures. The aortic rupture usually occurs in the lower portion of the artery located between the kidneys. Copper and lysine are both involved in elastin synthesis

    Comparisons of a Midget vs. a Standard Sized Strain of Laying Hens

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    Two new strains, one standard sized and the other approximately 70% as large, were acquired and tested for performance. The chicks were grown in floor pens to 20 weeks of age on standard growing diets and then placed in 12- and 16-inch layer cages. The hens were placed in cages at normal and high density, i.e., 3 or 4 hens per 12-inch cage and 4 or 5 hens per 16-inch cage. All were fed the same diet, 16% crude protein and 2900 Gal. M.E. The test lasted 10 months

    The power of low-resolution spectroscopy: On the spectral classification of planet candidates in the ground-based CoRoT follow-up

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    Planetary transits detected by the CoRoT mission can be mimicked by a low-mass star in orbit around a giant star. Spectral classification helps to identify the giant stars and also early-type stars which are often excluded from further follow-up. We study the potential and the limitations of low-resolution spectroscopy to improve the photometric spectral types of CoRoT candidates. In particular, we want to study the influence of the signal-to-noise ratio (SNR) of the target spectrum in a quantitative way. We built an own template library and investigate whether a template library from the literature is able to reproduce the classifications. Including previous photometric estimates, we show how the additional spectroscopic information improves the constraints on spectral type. Low-resolution spectroscopy (RÔëłR\approx1000) of 42 CoRoT targets covering a wide range in SNR (1-437) and of 149 templates was obtained in 2012-2013 with the Nasmyth spectrograph at the Tautenburg 2m telescope. Spectral types have been derived automatically by comparing with the observed template spectra. The classification has been repeated with the external CFLIB library. The spectral class obtained with the external library agrees within a few sub-classes when the target spectrum has a SNR of about 100 at least. While the photometric spectral type can deviate by an entire spectral class, the photometric luminosity classification is as close as a spectroscopic classification with the external library. A low SNR of the target spectrum limits the attainable accuracy of classification more strongly than the use of external templates or photometry. Furthermore we found that low-resolution reconnaissance spectroscopy ensures that good planet candidates are kept that would otherwise be discarded based on photometric spectral type alone.Comment: accepted for publication in Astronomische Nachrichten; 12 pages, 4 figures, 7 table

    Testing evolutionary tracks of Pre-Main Sequence stars: the case of HD113449

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    Evolutionary tracks are of key importance for the understanding of star formation. Unfortunately, tracks published by various groups differ so that it is fundamental to have observational tests. In order to do this, we intend to measure the masses of the two components of the Pre-Main Sequence binary HD113449 by combining radial velocity measurements taken with HARPS, with infrared interferometric data using AMBER on the VLTI. The spectroscopic orbit that has already been determined, combined with the first AMBER measurement, allows us to obtain a very first estimation of the inclination of the binary system and from this the masses of the two stars. More AMBER measurements of HD 113449 are needed to improve the precision on the masses: in the ESO period P82 two new measurements are scheduled.Comment: 4 pages, 3 figures; to appear in proceedings of Cool Star 15 conference, St.Andrews 200

    An algorithm for correcting CoRoT raw light curves

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    We introduce the CoRoT detrend algorithm (CDA) for detrending CoRoT stellar light curves. The algorithm CDA has the capability to remove random jumps and systematic trends encountered in typical CoRoT data in a fully automatic fashion. Since enormous jumps in flux can destroy the information content of a light curve, such an algorithm is essential. From a study of 1030 light curves in the CoRoT IRa01 field, we developed three simple assumptions which upon CDA is based. We describe the algorithm analytically and provide some examples of how it works. We demonstrate the functionality of the algorithm in the cases of CoRoT0102702789, CoRoT0102874481, CoRoT0102741994, and CoRoT0102729260. Using CDA in the specific case of CoRoT0102729260, we detect a candidate exoplanet around the host star of spectral type G5, which remains undetected in the raw light curve, and estimate the planetary parameters to be Rp=6.27Re and P=1.6986 days.Comment: 8 pages, 13 figure

    An infrared imaging search for low-mass companions to members of the young nearby beta Pic and Tucana/Horologium associations

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    We present deep high dynamic range infrared images of young nearby stars in the Tucana/Horologium and beta Pic associations, all ~ 10 to 35 Myrs young and at ~10 to 60 pc distance. Such young nearby stars are well-suited for direct imaging searches for brown dwarf and even planetary companions, because young sub-stellar objects are still self-luminous due to contraction and accretion. We performed our observations at the ESO 3.5m NTT with the normal infrared imaging detector SofI and the MPE speckle camera Sharp-I. Three arc sec north of GSC 8047-0232 in Horologium a promising brown dwarf companion candidate is detected, which needs to be confirmed by proper motion and/or spectroscopy. Several other faint companion candidates are already rejected by second epoch imaging. Among 21 stars observed in Tucana/Horologium, there are not more than one to five brown dwarf companions outside of 75 AU (1.5" at 50 pc); most certainly only < 5 % of the Tuc/HorA stars have brown dwarf companions (13 to 78 Jupiter masses) outside of 75 AU. For the first time, we can report an upper limit for the frequency of massive planets (~ 10 M_jup) at wide separations (~ 100 AU) using a meaningfull and homogeneous sample: Of 11 stars observed sufficiently deep in beta Pic (12 Myrs), not more than one has a massive planet outside of ~ 100 AU, i.e. massive planets at large separations are rare (< 9 %).Comment: Astronomische Nachrichten, in pres
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