1,571 research outputs found
Worker Morale in Russia: An Exploratory Study
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
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
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 -- NH Observations of an Absorption-contrast Selected IRDC Sample
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 s), have ammonia
column densities on the order of cm and molecular hydrogen
column densities on the order of cm. Their virial masses are
between 100 and a few 1000 M. 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
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
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
Study of morphology and stellar content of the Galactic HII region IRAS 16148-5011
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
NGC 2264 IRS1: The central engine and its cavity
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
Herschel observations of gamma-ray burst host galaxies: implications for the topology of the dusty interstellar medium
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&
- …