Spectroscopic and Photometric Study of the Contact Binary BO CVn

We present the results of the study of the contact binary system BO CVn. We have obtained physical parameters of the components based on combined analysis of new, multi-color light curves and spectroscopic mass ratio. This is the first time the latter has been determined for this object. We derived the contact configuration for the system with a very high filling factor of about 88 percent. We were able to reproduce the observed light curve, namely the flat bottom of the secondary minimum, only if a third light has been added into the list of free parameters. The resulting third light contribution is significant, about 20-24 percent, while the absolute parameters of components are: M1=1.16, M2=0.39, R1=1.62 and R2=1.00 (in solar units). The O-C diagram shows an upward parabola which, under the conservative mass transfer assumption, would correspond to a mass transfer rate of dM/dt = 6.3 \times 10-8M\odot/yr, matter being transferred from the less massive component to the more massive one. No cyclic, short-period variations have been found in the O-C diagram (but longer-term variations remain a possibility)Comment: 16 pages, 5 figures, 5 tables, accepted for publication by New Astronom

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

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

Are software engineers' responses to incomplete requirements related to project characteristics?

Software requirements quality affects software product quality. For high-quality software products, software requirements must be complete. When faced with incomplete requirements, software engineers attempt to fill the requirements' gaps differently, either by getting feedback from the user or by making assumptions. Assumptions may be explicit or implicit. Explicit assumptions are preferable to implicit assumptions as explicit assumptions can be validated. We conduct an empirical study to determine whether the number of explicit assumptions made by software engineers is related to a project's characteristics. Using data from two CMMI Level 3 companies and 16 projects, we investigated the responses of 92 software engineers to the same incomplete software requirement. Our findings show possible relationships between projects' characteristics and the number of explicit assumptions. ©2009 IEEE

Exploring religious tourist experiences in Jerusalem: The intersection of Abrahamic religions

By considering the importance of religious tourism for travel and the tourism industry, this study aims to identify religious tourists' experiences in Jerusalem, as one of the most important holy cities. By a survey, 848 data were collected from the Jewish, Christian, and Muslim religious tourists. Results showed that religious tourism experience was a multi-faceted construct, which consists of engaging mentally, discovering new things, interacting & belonging, connecting spiritually & emotionally, and relaxing & finding peace dimensions. By using these dimensions, perceived experience differences of tourists were examined depending on religion. Moreover, religious tourism experience was identified to significantly affect overall tourist satisfaction with Jerusalem. The study concluded with discussion of the findings and their implications

Biomechanics of aquatic plants and its role in flow-vegetation interactions

River hydrodynamicsBed roughness and flow resistanc

Characterization of Micrococcus luteus and Bacillus marisflavi Recovered from Common Dentex (Dentex dentex) Larviculture System

In this manuscript, thirty yellow-pigmented Gram-positive bacteria were isolated from natural intestine microflora and from sea water around the marine cage of a rearing tank of common dentex (Dentex dentex), in the Aegean Sea on the Turkish coast and were characterized. Eighteen isolates were assigned to the species Micrococcus luteus, the other twelve to the species Bacillus marisflavi. Eight representative strains, six from B. marisflavi and two from M. luteus, were chosen for further 16S rDNA analyses. A pathogenicity assay for the isolated bacterial strains was carried out in rainbow trout and it evidenced absence of pathogenicity in the tested strains. The isolated strains were tested for in vitro antagonistic activity against Listonella anguillarum, a pathogen bacterium diffused in Mediterranean aquaculture and affecting various fish species. The isolated bacterial strains showed antagonistic activity against the pathogenic bacterium, suggesting a possible role of isolates as probiotics. In this study, for the first time, bacterial strains of the species B. marisflavi, known as an environmental species, were recovered in the gut microbiota of a healthy fish. The use of the isolates characterized in this study, mainly the yellow-pigmented bacterium, is suggested as possible probiotics to improve fish health, along with alternative methods of maintaining a healthy environment

X-ray Doppler Imaging of 44i Boo with Chandra

Chandra High-Energy Transmission Grating observations of the bright eclipsing contact binary 44i Boo show X-ray line profiles which are Doppler-shifted by orbital motions. The X-ray emission spectrum contains a multitude of lines superimposed on a weak continuum, with strong lines of O VIII, Ne X, Fe XVII, and Mg XII. The profiles of these lines from the total observed spectrum show Doppler-broadened widths of ~ 550 km s^{-1}. Line centroids vary with orbital phase, indicating velocity changes of > 180 km s^{-1}. The first-order light curve shows significant variability, but no clear evidence for either primary or secondary eclipses. Flares are observed for all spectral ranges; additionally, the light curve constructed near the peak of the emission measure distribution (T_e = 5 to 8 X 10^6 K) shows quiescent variability as well as flares. The phase-dependences of line profiles and light curves together imply that at least half of the emission is localized at high latitude. A simple model with two regions on the primary star at relatively high latitude reproduces the observed line profile shifts and quiescent light curve. These first clear X-ray Doppler shifts of stellar coronal material illustrate the power of Chandra.Comment: 15 pages, 6 figures to be published in Astrophysical Journal Letter

Marked overlap of four genetic syndromes with dyskeratosis congenita confounds clinical diagnosis

Financial support provided by The Medical Research Council-MR/K000292/1, Children with Cancer- 2013/144 and Blood Wise-14032 (AJW, LC, SC, AE, TV, HT and ID). KMG is supported by the National Institute for Health Research through the NIHR Southampton Biomedical Research Centre

YOUNG ADOLESCENT EFL LEARNERS’ PERSPECTIVES ON CRITICAL THINKING SKILLS

Critical Thinking Skills (CTs) are among the 21st century learning skills, and schools are expected to equip the students with these skills.  Turkey has been restructuring the educational system in order to improve the quality of education which enables students to acquire such learning skills as critical and creative thinking, problem solving, and collaboration. The present study based on the perspectives of Young Adolescent EFF learners presents findings on the students’ awareness of CTs, and whether or not they apply them to a given task, and if there is any conflict between knowledge and application of CTs. The findings showed that the students, despite their quiet well awareness, they did not effectively apply CTs. The problems they encountered were assumed to be resulted from lacking in metacognitive knowledge

Observations of Lick Standard Stars Using the SCORPIO Multi-Slit Unit at the SAO 6-m Telescope

We present Lick line-index measurements of standard stars from the list of Worthey. The spectra were taken with the multi-slit unit of the SCORPIO spectrograph at the 6-m Special Astrophysical observatory telescope. We describe in detail our method of analysis and explain the importance of using the Lick index system for studying extragalactic globular clusters. Our results show that the calibration of our instrumental system to the standard Lick system can be performed with high confidence.Comment: 12 pages, 3 figure