130 research outputs found

    Business Faculty in Canadian Universities: Importance and Satisfaction Related to Job Characteristics

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    This paper examines the relationship between the importance and satisfaction of various job characteristics as perceived by 322 business faculty members teaching in 15 Canadian universities. The findings suggest that those aspects which the respondents felt to be most important were also those with which they were the least satisfied.Cette étude fail l'analyse des rapports entre l'importance et la satisfaction de diverses caractéristiques de l'emploi telles que perçues par 322 membres du corps enseignant de la Faculté des affaires commerciales à 15 universités canadiennes. Les résultats de l'enquête suggèrent que les aspects estimés les plus importants par les répondants étaient en même temps ceux avec lesquels ils exprimaient le moins de satisfaction

    Business Administration Students in Five Canadian Universities: A Study of Values

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    Using the Allport-Vernon-Lindzey (A VL ) for measuring dominant values, 513 business administration students from five schools in the Prairie Region were tested. The A VL scale measures relative importance of student values in six basic areas: theoretical, econo- mic, aesthetic, social, political and religious. The sample included 349 men and 164 women enrolled in different class levels (years 1 to 4) in five schools of business. Significant differences were found between business student values and the norms for the general college population, and between the values of male and female business adminis- tration students. Differences were progressively less significant when business students were compared by class levels and by schools.En utilisant l'échelle Allport-Vernon-Lindzey (A VL) pour mesurer les valeurs dominantes, on a échantilloné 513 étudiants des cours d'administration commerciale à cinq établisse-ments de la région des Prairies. L'échelle A VL mesure l'importance relative des valeurs des étudiants dans six champs fondamentaux: les domaines théorique, économique, esthétique, social, politique et religieux. L'échantillon comprenait 349 hommes et 164 femmes inscrits à divers niveaux (première année jusqu 'à la quatrième année) de cinq écoles d'administra-tion. On a constaté des différences significatives entre les valeurs des étudiants en adminis-tration et les normes pour la population générale des établissements post-secondaires, et aussi entre les valeurs des étudiants mâles et celles des étudiants femelles en administration commerciale. Les différences se faisaient progressivement moins significatives quand on comparait entre eux les étudiants en administration de différentes années ou fréquentant différentes établissements

    Eclipsing Binaries in the OGLE Variable Star Catalogs.V. Long-Period Beta Lyrae-type Systems in the Small Magellanic Cloud and the PLC-beta Relation

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    Thirty eight long-period (P>10 days), apparently contact binary stars discovered by the OGLE-II project in the SMC appear to be Beta Lyrae-type systems with ellipsoidal variations of the cool components dominating over eclipse effects in the systemic light variations and in the total luminosity. A new period-luminosity- color (PLC) relation has been established for these systems; we call it the PLC-beta relation, to distinguish it from the Cepheid relation. Two versions of the PLC-beta relation - based on the (B-V)0 or (V-I)0 color indices - have been calibrated for 33 systems with (V-I)0>0.25 spanning the orbital period range of 11 to 181 days. The relations can provide maximum-light, absolute-magnitude estimates accurate to epsilon-M_V~0.35 mag. within the approximate range -3<M_V<+1. In terms of their number in the SMC, the long-period Beta Lyrae-type binaries are about 50 times less common than the Cepheids. Nevertheless, their large luminosities coupled with continuous light variations make these binaries very easy to spot in nearby galaxies, so that the PLC-beta relation can offer an auxiliary and entirely independent method of distance determination to nearby stellar systems rich in massive stars. The sample of the long-period Beta Lyrae systems in the SMC analyzed in this paper is currently the best defined and uniform known sequence of such binaries.Comment: submitted for publication in Astronomical Journal; 8 PS figures, 2 table

    A search for transits of GJ 581\lowercase{e} and characterization of the host star variability using MOST space telescope photometry

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    The GJ 581 system has been amply studied since its discovery in 2005: the number of known planets in the system has increased and their orbital parameters are among the most precisely determined for radial velocity detected exoplanets. We have acquired MOST space-based photometry during 2007 and 2009, with the aims of measuring the stellar variability and searching for transits of GJ 581e, respectively. We quantify our sensitivity to shallow transit signals using Monte Carlo simulations, and perform a transit search within the 3σ\sigma transit windows corresponding to both the circular and Keplerian orbit ephemerides. Our analysis rules out transits for a planet with an orbital period of 3.15 days (GJ 581 e) having a radius larger than 1.62 RR_{\oplus} (or a density lower than 2.39 g cm3^{-3} for an orbital inclination of 90^{\circ}) to 2σ\sigma confidence. Thus, if the planet transits, we can exclude hydrogen, helium and water theoretical model compositions. The MOST photometry also allows us to rule out transits of GJ 581b within the Keplerian orbit-derived transit window for impact parameter values smaller than \sim0.4 and confirm previous results which exclude transits for this planet within the circular orbit-derived transit window, for all plausible interior compositions. We find that the stellar brightness of GJ 581 is stable to within 1%, a characteristic which is favourable to the development of life in the habitable zone of the system. In the 2009 photometry, we detect a stellar signal with a period of 5.586 ±\pm 0.051 days, which is close to the orbital period of GJ 581b (P=P=5.37 days). However, further monitoring of the system is necessary to verify the nature of this variation.Comment: 11 pages, 2 tables, 10 figures; accepted for publication in Ap

    Photometric variability in FU Ori and Z CMa as observed by MOST

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    Photometric observations obtained by the MOST satellite were used to characterize optical small scale variability of the young stars FU Ori and Z CMa. Wavelet analysis for FU Ori reveals the possible existence of several 2-9 d quasi-periodic features occurring nearly simultaneously; they may be interpreted as plasma parcels or other localized disc heterogeneities revolving at different Keplerian radii in the accretion disc. Their periods may shorten slowly which may be due to spiralling in of individual parcels toward the inner disc radius, estimated at 4.8+/-0.2 R_sun. Analysis of additional multicolour data confirms the previously obtained relation between variations in the B-V colour index and the V magnitude. In contrast to the FU Ori results, the oscillation spectrum of Z CMa does not reveal any periodicities with the wavelet spectrum possibly dominated by outburst of the Herbig Be component.Comment: Accepted by MNRA

    W UMa-type Binary Stars in Globular Clusters

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    A sample of 86 contact binary systems in 14 globular clusters with available color index data in (B-V) or in (V-I) has been analyzed. At least one third of all systems are numerous foreground Galactic Disk projections over long lines of sight to the clusters. Since the selection of the cluster members has been based on the MV(logP, color) calibrations, the matter of a metallicity-correction required particular attention with the result that such a correction is apparently not needed at the present level of accuracy. Analysis of the color-magnitude and period-color relations shows that globular cluster members are under-luminous relative to the Galactic Disk contact systems mainly because of the smaller sizes and, consequently, shorter orbital periods; the color-index effect of the diminished blanketing is less important, especially for (V-I). The variability amplitudes for the Blue Straggler systems show a significantly different distribution from that for systems below the Turn Off Point (TOP): The BS systems show only small amplitudes while the distribution for the systems below the TOP is peculiar in containing only large amplitude systems. This difference is linked to an observational selection effect so that efforts at determining the frequency of occurrence of the contact systems below the TOP have been judged to be premature; the frequency among the BS stars could be at about 45+-10 BS stars per one contact BS binary.Comment: submitted for publication in Astronomical Journal; 8 figures, 3 tables (Table 1 in landscape

    A stable quasi-periodic 4.18 d oscillation and mysterious occultations in the 2011 MOST light curve of TWHya

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    We present an analysis of the 2011 photometric observations of TW Hya by the MOST satellite; this is the fourth continuous series of this type. The large-scale light variations are dominated by a strong, quasi-periodic 4.18 d oscillation with superimposed, apparently chaotic flaring activity; the former is most likely produced by stellar rotation with one large hot spot created by a stable accretion funnel in the stable regime of accretion while the latter may be produced by small hot spots, created at moderate latitudes by unstable accretion tongues. A new, previously unnoticed feature is a series of semi-periodic, well defined brightness dips of unknown nature of which 19 were observed during 43 days of our nearly-continuous observations. Re-analysis of the 2009 MOST light curve revealed the presence of 3 similar dips. On the basis of recent theoretical results, we tentatively conclude that the dips may represent occultations of the small hot spots created by unstable accretion tongues by hypothetical optically thick clumps.Comment: Printed in MNRA

    Radial Velocity Studies of Close Binary Stars.VII. Methods and Uncertainties

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    Methods used in the radial-velocity program of short-period binary systems at the David Dunlap Observatory are described with particular stress on the Broadening Function (BF) formalism. This formalism has permitted determination of radial velocities from complex spectra of multiple-component systems with component stars showing very different degree of rotational line broadening. The statistics of random errors of orbital parameters is discussed on the basis of the available orbital solutions presented in the six previous papers of the series, each with ten orbits. The difficult matter of systematic uncertainties in orbital parameters is illustrated for one typical case of GM Dra from the most recent Paper VI.Comment: AASTeX5, 5 figures, extensively modified after the AJ revie

    Investigating Ca II emission in the RS CVn binary ER Vulpeculae using the Broadening Function Formalism

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    The synchronously rotating G stars in the detached, short-period (0.7 d), partially eclipsing binary, ER Vul, are the most chromospherically active solar-type stars known. We have monitored activity in the Ca II H & K reversals for almost an entire orbit. Rucinski's Broadening Function Formalism allows the photospheric contribution to be objectively subtracted from the highly blended spectra. The power of the BF technique is also demonstrated by the good agreement of radial velocities with those measured by others from less crowded spectral regions. In addition to strong Ca II emission from the primary and secondary, there appears to be a high-velocity stream flowing onto the secondary where it stimulates a large active region on the surface 30 - 40 degrees in advance of the sub-binary longitude. A model light curve with a spot centered on the same longitude also gives the best fit to the observed light curve. A flare with approximately 13% more power than at other phases was detected in one spectrum. We suggest ER Vul may offer a magnified view of the more subtle chromospheric effects synchronized to planetary revolution seen in certain `51 Peg'-type systems.Comment: Accepted to AJ; 17 pages and 16 figure
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