Influence of interstellar and atmospheric extinction on light curves of eclipsing binaries

Interstellar and atmospheric extinctions redden the observational photometric data and they should be handled rigorously. This paper simulates the effect of reddening for the modest case of two main sequence T1 = 6500K and T2 = 5500K components of a detached eclipsing binary system. It is shown that simply subtracting a constant from measured magnitudes (the approach often used in the field of eclipsing binaries) to account for reddening should be avoided. Simplified treatment of the reddening introduces systematics that reaches \~0.01mag for the simulated case, but can be as high as ~0.2mag for e.g. B8V--K4III systems. With rigorous treatment, it is possible to uniquely determine the color excess value E(B-V) from multi-color photometric light curves of eclipsing binaries.Comment: 6 pages, 9 figures, 1 table, Kopal's Binary Star Legacy conference contribution (Litomysl 2004), to be published by Kluwer A&S

Trauma-related psychological disorders among Palestinian children and adults in Gaza and West Bank, 2005-2008

BACKGROUND: Trauma from war and violence has led to psychological disorders in individuals living in the Gaza strip and West Bank. Few reports are available on the psychiatric disorders seen in children and adolescents or the treatment of affected populations. This study was conducted in order to describe the occurrence and treatment of psychiatric disorders in the Palestinian populations of the Gaza strip and Nablus district in the West Bank. METHODS: From 2005 to 2008, 1369 patients aged more than 1 year were identified through a local mental health and counseling health network. All were clinically assessed using a semi-structured interview based on the DSM-IV-TR criteria. RESULTS: Among 1254 patients, 23.2% reported post-traumatic stress disorder [PTSD], 17.3% anxiety disorder (other than PTSD or acute stress disorder), and 15.3% depression. PTSD was more frequently identified in children < or = 15 years old, while depression was the main symptom observed in adults. Among children < or = 15 years old, factors significantly associated with PTSD included being witness to murder or physical abuse, receiving threats, and property destruction or loss (p < 0.03). Psychological care, primarily in the form of individual, short-term psychotherapy, was provided to 65.1% of patients, with about 30.6% required psychotropic medication. Duration of therapy sessions was higher for children < or = 15 years old compared with adults (p = 0.05). Following psychotherapy, 79.0% had improved symptoms, and this improvement was significantly higher in children < or = 15 years old (82.8%) compared with adults (75.3%; p = 0.001). CONCLUSION: These observations suggest that short-term psychotherapy could be an effective treatment for specific psychiatric disorders occurring in vulnerable populations, including children, living in violent conflict zones, such as in Gaza strip and the West Bank

Noise Effects on Synchronized Globally Coupled Oscillators

The synchronized phase of globally coupled nonlinear oscillators subject to noise fluctuations is studied by means of a new analytical approach able to tackle general couplings, nonlinearities, and noise temporal correlations. Our results show that the interplay between coupling and noise modifies the effective frequency of the system in a non trivial way. Whereas for linear couplings the effect of noise is always to increase the effective frequency, for nonlinear couplings the noise influence is shown to be positive or negative depending on the problem parameters. Possible experimental verification of the results is discussed.Comment: 6 Pages, 4 EPS figures included (RevTeX and epsfig needed). Submitted to Phys. Re

Disentangling effective temperatures of individual eclipsing binary components by means of color-index constraining

Eclipsing binary stars are gratifying objects because of their unique geometrical properties upon which all important physical parameters such as masses, radii, temperatures, luminosities and distance may be obtained in absolute scale. This poses strict demand on the model to be free of systematic effects that would influence the results later used for calibrations, catalogs and evolution theory. We present an objective scheme of obtaining individual temperatures of both binary system components by means of color-index constraining, with the only requirement that the observational data-set is acquired in a standard photometric system. We show that for a modest case of two similar main-sequence components the erroneous approach of assuming the temperature of the primary star from the color index yields temperatures which are systematically wrong by ~100K.Comment: 6 pages, 3 figures, 1 table; to appear in proceedings of the Close Binaries in the 21st Century conference in Syros, Greec

Mobile services adoption in a hospitality consumer context

Purpose: This study presents a model drawn on both the extension of the unified theory of acceptance and use of technology (UTAUT2) and the perceived value for explaining consumer behavior toward mobile hospitality services (MHS) from two perspectives: intention to use and recommendation. Design/methodology/approach: The partial least square (PLS) was applied to data gathered from 348 validated responses to a survey in order to test a number of research hypotheses. Findings: Results found that the proposed conceptual model explains 62% of the intention to use MHS, and 51% of the variation in recommendation. Perceived value plays a role in explaining both the intention to use and recommend MHS, with both constructs also helping in explaining behavior intention, to which effort expectancy facilitating conditions and performance expectancy also contribute. Originality/value: This research goes beyond perceived value by combining it with a cornerstone model used in technology adoption studies, the UTAUT2. The paper addresses updated mobile hospitality services that include but are not limited to mobile hotel reservations.info:eu-repo/semantics/acceptedVersio

Signatures of Planets in Spatially Unresolved Disks

Main sequence stars are commonly surrounded by debris disks, composed of cold dust continuously replenished by a reservoir of undetected dust-producing planetesimals. In a planetary system with a belt of planetesimals (like the Solar System's Kuiper Belt) and one or more interior giant planets, the trapping of dust particles in the mean motion resonances with the planets can create structure in the dust disk, as the particles accumulate at certain semimajor axes. Sufficiently massive planets may also scatter and eject dust particles out of a planetary system, creating a dust depleted region inside the orbit of the planet. In anticipation of future observations of spatially unresolved debris disks with the Spitzer Space Telescope, we are interested in studying how the structure carved by planets affects the shape of the disk's spectral energy distribution (SED), and consequently if the SED can be used to infer the presence of planets. We numerically calculate the equilibrium spatial density distributions and SEDs of dust disks originated by a belt of planetesimals in the presence of interior giant planets in different planetary configurations, and for a representative sample of chemical compositions. The dynamical models are necessary to estimate the enhancement of particles near the mean motion resonances with the planets, and to determine how many particles drift inside the planet's orbit. Based on the SEDs and predicted $\it{Spitzer}$ colors we discuss what types of planetary systems can be distinguishable from one another and the main parameter degeneracies in the model SEDs.Comment: 40 pages (pre-print form), including 16 figures. Published in ApJ 200

Understanding the importance of sport stadium visits to teams and cities through the eyes of online reviewers

This study explores the relationships among sport stadium visitors’ experiences, satisfaction, team brand image, and destination image. A text mining approach was first used to analyse 26,538 individual reviews from 17 European sport stadiums on TripAdvisor. The online reviews were then used as input to create a word frequency of each individual review and construct a structural equation model. Results indicate that the visitor experience had a strong impact on team brand image and a moderate effect on destination image. Satisfaction mediated the influence of the visitor experience on team brand image, but not on destination image. Team brand image exerted a significant but small impact on destination image. These findings show that stadium visits impact the marketing of both host teams and cities. City, leisure and stadium managers should therefore coordinate their efforts to highlight teams as part of a city’s cultural brand to generate image-based benefits for both.info:eu-repo/semantics/publishedVersio

Empowered learning through microworlds and teaching methods: a text mining and meta-analysis-based systematic review

Microworlds are simulations in computational environments where the student can manipulate objects and learn from those manipulations. Since their creation, they have been used in a wide range of academic areas to improve students learning from elementary school to college. However, their effectiveness is unclear since many studies do not measure the acquired knowledge after the use of microworlds but instead they focus on self-evaluation. Furthermore, it has not been clear whether its effect on learning is related to the teaching method. In this study, we perform a meta-analysis to ascertain the impact of microworlds combined with different teaching methods on students’ knowledge acquisition. We applied a selection criterion to a collection of 668 studies and were left with 10 microworld applications relevant to our learning context. These studies were then assessed through a meta-analysis using effect size with Cohen’s d and p-value. Our analysis shows that the cognitive methods combined with microworlds have a great impact on the knowledge acquisition (d = 1.03; p &lt; 0.001) but failed to show a significant effect (d = 0.21) for expository methods.info:eu-repo/semantics/publishedVersio