169 research outputs found
Working conditions, work-life conflict and wellbeing in UK prison officers: the role of affective rumination and detachment
Although prison officers experience the working conditions associated with work-life conflict, little research has explored this issue. This study draws upon the work-home resources model (ten Brummelhuis & Bakker, 2012) to investigate relationships between working conditions (demands and experiences of aggression) and time-based, strain-based and behavior-based work-life conflict in UK prison officers (n = 1,682). Associations between working conditions, work-life conflict, and emotional exhaustion were also examined. Two recovery behaviors (affective rumination and detachment) were considered as potential moderators of associations between working conditions and emotional exhaustion. High levels of all work-life conflict dimensions were found which were related to working conditions and emotional exhaustion. Some evidence was found that higher rumination and lower detachment exacerbated the positive association between both job demands and aggression and emotional exhaustion. The implications of the findings for the wellbeing and professional functioning of prison officers are discussed, together with key areas for future research
The Metallicity Dependence of the Fourier Components of RR Lyrae Light Curves is the Oosterhoff/Arp/Preston Period Ratio Effect in Disguise
The correlation of particular Fourier components of the light curves of RR
Lyrae variables with metallicity, discovered by Simon and later by Kovacs and
his coworkers, is shown to have the same explanation as the period ratios
(period shifts in log P) between RRab Lyrae variables that have the same
colors, amplitudes, and light-curve shapes but different metallicities. A
purpose of this paper is to demonstrate that the model which predicts the
period-metallicity relations is the mediating parameters of colors, amplitudes,
and light-curve shapes also explains the Simon/Kovacs et al. correlation
between period, Phi_31, and metallicity. The proof is made by demonstrating
that the combination of the first and third phase terms in a Fourier
decomposition of RRab light curves, called Phi_31 by Simon and Lee, varies
monotonically across the RR Lyrae instability strip in the same way that
amplitude, color, and rise time vary with period within the strip. The premise
of the model is that if horizontal branches at the RR Lyrae strip are stacked
in luminosity according to the metallicity, then there necessarily must be a
log period shift between RR Lyraes with different metallicities at the same
Phi_31 values. However, there are exceptions to the model. (...)Comment: 17 pages, 8 figures, 1 table. Accepted for publication in The A
Anisotropies in the Motions and Positions of the Galactic Globular Clusters
The velocity ellipsoid for 38 globular clusters with [Fe/H] <= -1.0 is
derived and shown to be significantly anisotropic with major axis directed
towards low Galactic latitude. Principal axes of the spatial distribution of
different groups of clusters are derived and compared with the velocity
ellipsoid. The metal poor cluster spatial distribution is significantly
flattened along an axis which coincides within the uncertainties with the major
axis of the velocity ellipsoid. Given the observed steep age-metallicity
relation for metal poor clusters, one speculative interpretation of the data is
that an initially flattened filament underwent a relatively rapid initial
transverse collapse forming satellite galaxies and metal poor globular clusters
while the protogalaxy collapsed and assembled more slowly along the filament
acquiring and/or redistributing angular momentum in the process.Comment: 10 pages, 1 figure, accepted for publication in ApJ Letter
The Kinematic Properties of BHB and RR Lyrae stars towards the Anticentre and the North Galactic Pole: The Transition between the Inner and the Outer Halo
We identify 51 blue horizontal branch (BHB) stars, 12 possible BHB stars and
58 RR Lyrae stars in Anticentre fields. Their selection does not depend on
their kinematics. Light curves and ephemerides are given for 7 previously
unknown RR Lyrae stars. All but 4 of the RR Lyrae stars are of Oosterhoff type
I. Our selection criteria for BHB stars give results that agree with those used
by Smith et al. (2010) and Ruhland et al. (2011). We use 5 methods to determine
distances for the BHB stars and 3 methods for the RR Lyrae stars to get
distances on a uniform scale. Absolute proper motions (largely derived from the
GSCII and SDSS (DR7) databases) are given for these stars; radial velocities
are given for 31 of the BHB stars and 37 of the RR Lyrae stars. Combining these
data for BHB and RR Lyrae stars with those previously found in fields at the
North Galactic Pole, we find that retrograde orbits dominate for galactocentric
distances greater than 12.5 kpc. The majority of metal-poor stars in the solar
neighbourhood are known to be concentrated in a Lperp vs. Lz angular momentum
plot. We show that the ratio of the number of outliers to the number in the
main concentration increases with galactocentric distance. The location of
these outliers with Lperp and Lz shows that the halo BHB and RR Lyrae stars
have more retrograde orbits and a more spherical distribution with increasing
galactocentric distance. Six RR Lyrae stars are identified in the H99 group of
outliers; the small spread in their [Fe/H] suggests that they could have come
from a single globular cluster. Another group of outliers contains two pairs of
RR Lyrae stars; the stars in each pair have similar properties.Comment: 40 pages, 19 figures, to be published in MNRA
Kinematic Structure in the Galactic Halo at the North Galactic Pole: RR Lyrae and BHB Stars show different kinematics
Space motions are given for 38 RR Lyrae (RRL) stars and 79 blue horizontal
branch (BHB) stars in a ~200 deg2 area around the North Galactic Pole (NGP)
using a homogeneous distance scale consistent with (m-M)0=18.52 for the LMC.
The kinematics of the 26 RRL and 52 BHB stars in the 10.4 cubic kpc volume
that have Z<8 kpc are not homogeneous. Our BHB sample (like that of Sirko et
al. 2004b) has a zero galactic rotation (V_phi) and roughly isotropic velocity
dispersions. The RRL sample shows a definite retrograde rotation (V_phi =
-95+/-29 km/s) and non-isotropic velocity dispersions. The combined BHB and RRL
sample has a retrograde galactic rotation (V) that is similar to that found by
Majewski (1992) for his sample of subdwarfs in SA 57. The velocity dispersion
of the RRL stars that have a positive W motion is significantly smaller than
the dispersion of those "streaming down" with a negative W.
One component of our sample (rich in RRL's) shows retrograde rotation and the
streaming motion that we associate with the accretion process. The other
(traced by the BHB stars) shows essentially no rotation and less evidence of
streaming. These two components have HB morphologies that suggest that they may
be the field star equivalents of the young and old halo globular clusters
respectively.Comment: Accepted for publication on MNRAS. 20 pages, 7 figures, 12 table
Cosmic Star Formation History from Local Observations and an Outline for Galaxy Formation and Evolution
The goal of this investigation is to reconstruct the cosmic star formation
rate density history from local observations and in doing so to gain insight
into how galaxies might have formed and evolved. A new chemical evolution model
is described which accounts for the formation of globular clusters as well as
the accompanying field stars. When this model is used in conjunction with the
observed age metallicity relations for the clusters and with input which allows
for the formation of the nearly universally observed bimodal distribution of
globular clusters, star formation rates are obtained. By confining attention to
a representative volume of the local universe, these rates allow a successful
reconstruction of the Madau plot while complementary results similtaneously
satisfy many local cosmological constraints. A physical framework for galaxy
formation is presented which incorporates the results from this chemical
evolution model and assumes an anisotropic collapse. In addition to providing
the `classical' halo, bulge and disk components, the model also predicts a new
stellar halo component with peak [Fe/H] ~ -0.8 and disk-like angular momentum
and allows for the formation of a thick disk as outlined by the group of metal
rich globular clusters. Milky Way counterparts of the latter two components are
identified.Comment: 32 pages, 6 figs accepted by Ap
A Preliminary Discussion of the Kinematics of BHB and RR Lyrae Stars near the North Galactic Pole
The radial velocity dispersion of 67 RR Lyrae variable and blue horizontal
branch (BHB) stars that are more than 4 kpc above the galactic plane at the
North Galactic Pole is 110 km/sec and shows no trend with Z (the height above
the galactic plane). Nine stars with Z < 4 kpc show a smaller velocity
dispersion (40 +/-9 km/sec) as is to be expected if they mostly belong to a
population with a flatter distribution. Both RR Lyrae stars and BHB stars show
evidence of stream motion; the most significant is in fields RR2 and RR3 where
24 stars in the range 4.0 < Z < 11.0 kpc have a mean radial velocity of -59 +/-
16 km/sec. Three halo stars in field RR 2 appear to be part of a moving group
with a common radial velocity of -90 km/sec. The streaming phenomenon therefore
occurs over a range of spatial scales. The BHB and RR Lyrae stars in our sample
both have a similar range of metallicity (-1.2 < [Fe/H] < -2.2). Proper motions
of BHB stars in fields SA 57 (NGP) and the Anticenter field (RR 7) (both of
which lie close to the meridional plane of the Galaxy) show that the stars that
have Z 4 kpc have a Galactic V motion that is
< -200 km/sec and which is characteristic of the halo. Thus the stars that have
a flatter distribution are really halo stars and not members of the metal-weak
thick-disk.Comment: Accepted for publication in the March 1996 AJ. 15 pages, AASTeX V4.0
latex format (including figures), 2 eps figures, 2 separate AASTeX V4.0 latex
table
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