1,550 research outputs found

    Worker Morale in Russia: An Exploratory Study

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    Despite unanimous agreement in the existing literature that morale influences employee performance, no well-defined measure of morale exists. Our study develops a robust measure of morale and focuses on the factors that influence morale among Russian workers. Survey data were collected from Russian employees at two different points in time, 1995 and 2002, in five Russian cities. Among the workers participating in our study, expectation of receiving a desired reward contributes to high morale, with expected monetary rewards having a larger influence than expected non-monetary rewards, but praise for a job well done and a feeling of accomplishment also contribute positively to employee morale. There is a significant correlation between positive attitudes toward work and morale, and a positive correlation between performance assessment and morale. Demographic characteristics (age and gender) have no discernable influence on morale when controls are included for work experience.http://deepblue.lib.umich.edu/bitstream/2027.42/57196/1/wp816 .pd

    Worker Morale in Russia: An Exploratory Study

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    Despite unanimous agreement in the existing literature that morale influences employee performance, no well-defined measure of morale exists. Our study develops a robust measure of morale and focuses on the factors that influence morale among Russian workers. Survey data were collected from Russian employees at two different points in time, 1995 and 2002, in five Russian cities. Among the workers participating in our study, expectation of receiving a desired reward contributes to high morale, with expected monetary rewards having a larger influence than expected non-monetary rewards, but praise for a job well done and a feeling of accomplishment also contribute positively to employee morale. There is a significant correlation between positive attitudes toward work and morale, and a positive correlation between performance assessment and morale. Demographic characteristics (age and gender) have no discernable influence on morale when controls are included for work experience.Morale, Russia, Expected rewards, Motivation, Performance

    Infrared variability, maser activity, and accretion of massive young stellar objects

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    Methanol and water masers indicate young stellar objects. They often exhibit flares, and a fraction shows periodic activity. Several mechanisms might explain this behavior but the lack of concurrent infrared (IR) data complicates to identify the cause. Recently, 6.7 GHz methanol maser flares were observed, triggered by accretion bursts of high-mass YSOs which confirmed the IR-pumping of these masers. This suggests that regular IR changes might lead to maser periodicity. Hence, we scrutinized space-based IR imaging of YSOs associated with periodic methanol masers. We succeeded to extract the IR light curve from NEOWISE data for the intermediate mass YSO G107.298+5.639. Thus, for the first time a relationship between the maser and IR variability could be established. While the IR light curve shows the same period of ~34.6 days as the masers, its shape is distinct from that of the maser flares. Possible reasons for the IR periodicity are discussed.Comment: 4 pages, 3 figures, to be published in: Proceedings IAU Symposium 336 "Astrophysical Masers: Unlocking the Mysteries of the Universe", Editors: A. Tarchi, M.J. Reid & P. Castangia, updated version with hyperlinks adde

    Characterization of Infrared Dark Clouds -- NH3_3 Observations of an Absorption-contrast Selected IRDC Sample

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    Despite increasing research in massive star formation, little is known about its earliest stages. Infrared Dark Clouds (IRDCs) are cold, dense and massive enough to harbour the sites of future high-mass star formation. But up to now, mainly small samples have been observed and analysed. To understand the physical conditions during the early stages of high-mass star formation, it is necessary to learn more about the physical conditions and stability in relatively unevolved IRDCs. Thus, for characterising IRDCs studies of large samples are needed. We investigate a complete sample of 218 northern hemisphere high-contrast IRDCs using the ammonia (1,1)- and (2,2)-inversion transitions. We detected ammonia (1,1)-inversion transition lines in 109 of our IRDC candidates. Using the data we were able to study the physical conditions within the star-forming regions statistically. We compared them with the conditions in more evolved regions which have been observed in the same fashion as our sample sources. Our results show that IRDCs have, on average, rotation temperatures of 15 K, are turbulent (with line width FWHMs around 2 km s1^{-1}), have ammonia column densities on the order of 101410^{14} cm2^{-2} and molecular hydrogen column densities on the order of 102210^{22} cm2^{-2}. Their virial masses are between 100 and a few 1000 M_\odot. The comparison of bulk kinetic and potential energies indicate that the sources are close to virial equilibrium. IRDCs are on average cooler and less turbulent than a comparison sample of high-mass protostellar objects, and have lower ammonia column densities. Virial parameters indicate that the majority of IRDCs are currently stable, but are expected to collapse in the future.Comment: 21 pages, 11 figures, 7 tables. Paper accepted for publication in Astronomy & Astrophysic

    Influence of the Dufour effect on convection in binary gas mixtures

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    Linear and nonlinear properties of convection in binary fluid layers heated from below are investigated, in particular for gas parameters. A Galerkin approximation for realistic boundary conditions that describes stationary and oscillatory convection in the form of straight parallel rolls is used to determine the influence of the Dufour effect on the bifurcation behaviour of convective flow intensity, vertical heat current, and concentration mixing. The Dufour--induced changes in the bifurcation topology and the existence regimes of stationary and traveling wave convection are elucidated. To check the validity of the Galerkin results we compare with finite--difference numerical simulations of the full hydrodynamical field equations. Furthermore, we report on the scaling behaviour of linear properties of the stationary instability.Comment: 14 pages and 10 figures as uuencoded Postscript file (using uufiles

    Linear Parsing Expression Grammars

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    PEGs were formalized by Ford in 2004, and have several pragmatic operators (such as ordered choice and unlimited lookahead) for better expressing modern programming language syntax. Since these operators are not explicitly defined in the classic formal language theory, it is significant and still challenging to argue PEGs' expressiveness in the context of formal language theory.Since PEGs are relatively new, there are several unsolved problems.One of the problems is revealing a subclass of PEGs that is equivalent to DFAs. This allows application of some techniques from the theory of regular grammar to PEGs. In this paper, we define Linear PEGs (LPEGs), a subclass of PEGs that is equivalent to DFAs. Surprisingly, LPEGs are formalized by only excluding some patterns of recursive nonterminal in PEGs, and include the full set of ordered choice, unlimited lookahead, and greedy repetition, which are characteristic of PEGs. Although the conversion judgement of parsing expressions into DFAs is undecidable in general, the formalism of LPEGs allows for a syntactical judgement of parsing expressions.Comment: Parsing expression grammars, Boolean finite automata, Packrat parsin

    NGC 2264 IRS1: The central engine and its cavity

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    We present a high-resolution study of NGC 2264 IRS1 in CS(2-1) and in the 3-mm continuum using the IRAM Plateau de Bure Interferometer. We complement these radio data with images taken at 2.2, 4.6, and 11.9 micron. The combined information allow a new interpretation of the closest environment of NGC 2264 IRS1. No disk around the B-type star IRS1 was found. IRS1 and its low-mass companions are located in a low-density cavity which is surrounded by the remaining dense cloud core which has a clumpy shell-like structure. Strong evidence for induced on-going star formation was found in the surroundings of IRS1. A deeply embedded very young stellar object 20 arcsec to the north of IRS1 is powering a highly collimated bipolar outflow. The object 8 in the closer environment of IRS1 is a binary surrounded by dusty circumbinary material and powering two bipolar outflows.Comment: 17 pages, 6 figures, The paper is accepted and will appear in the Astrophysical Journal, Vol 599, No 1 (issue December 10). A high-resolution postscript version of this paper is available here ( http://www.astro.uni-jena.de/Users/martin/publi.html). Furthermore, you can find a high resolution PDF file here ( http://www.tls-tautenburg.de/research/tls-research/pub2003.html

    Study of morphology and stellar content of the Galactic HII region IRAS 16148-5011

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    An investigation of the IRAS 16148-5011 region - a cluster at a distance of 3.6 kpc - is presented here, carried out using multiwavelength data in near-infrared (NIR) from the 1.4m Infrared Survey Facility telescope, mid-infrared (MIR) from the archival Spitzer GLIMPSE survey, far-infrared (FIR) from the Herschel archive, and low-frequency radio continuum observations at 1280 and 843 MHz from the Giant Metrewave Radio Telescope (GMRT) and Molonglo Survey archive, respectively. A combination of NIR and MIR data is used to identify 7 Class I and 133 Class II sources in the region. Spectral Energy Distribution (SED) analysis of selected sources reveals a 9.6 Msolar, high-mass source embedded in nebulosity. However, Lyman continuum luminosity calculation using radio emission - which shows a compact HII, region - indicates the spectral type of the ionizing source to be earlier than B0-O9.5. Free-free emission SED modelling yields the electron density as 138 cm^{-3}, and thus the mass of the ionized hydrogen as ~16.4 Msolar. Thermal dust emission modelling, using the FIR data from Herschel and performing modified blackbody fits, helped us construct the temperature and column density maps of the region, which show peak values of 30 K and 3.3x10^{22} cm^{-2}, respectively. The column density maps reveal an AV > 20 mag extinction associated with the nebular emission, and weak filamentary structures connecting dense clumps. The clump associated with this IRAS object is found to have dimensions of ~1.1 pc x 0.8 pc, and a mass of 1023 Msolar.Comment: 20 pages, 12 figures, 3 tables, Accepted for publication in MNRA

    Herschel observations of gamma-ray burst host galaxies: implications for the topology of the dusty interstellar medium

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    Long-duration gamma-ray bursts (GRBs) are indisputably related to star formation, and their vast luminosity in gamma rays pin-points regions of star formation independent of galaxy mass. As such, GRBs provide a unique tool for studying star forming galaxies out to high-z independent of luminosity. Most of our understanding of the properties of GRB hosts (GRBHs) comes from optical and near-infrared (NIR) follow-up observations, and we therefore have relatively little knowledge of the fraction of dust-enshrouded star formation that resides within GRBHs. Currently ~20% of GRBs show evidence of significant amounts of dust along the line of sight to the afterglow through the host galaxy, and these GRBs tend to reside within redder and more massive galaxies than GRBs with optically bright afterglows. In this paper we present Herschel observations of five GRBHs with evidence of being dust-rich, targeted to understand the dust attenuation properties within GRBs better. Despite the sensitivity of our Herschel observations, only one galaxy in our sample was detected (GRBH 070306), for which we measure a total star formation rate (SFR) of ~100Mstar/yr, and which had a relatively high stellar mass (log[Mstar]=10.34+0.09/-0.04). Nevertheless, when considering a larger sample of GRBHs observed with Herschel, it is clear that stellar mass is not the only factor contributing to a Herschel detection, and significant dust extinction along the GRB sightline (A_{V,GRB}>1.5~mag) appears to be a considerably better tracer of GRBHs with high dust mass. This suggests that the extinguishing dust along the GRB line of sight lies predominantly within the host galaxy ISM, and thus those GRBs with A_{V,GRB}>1~mag but with no host galaxy Herschel detections are likely to have been predominantly extinguished by dust within an intervening dense cloud.Comment: 14 pages, 7 figures. Accepted for publication in A&
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