1,260 research outputs found
Recommended from our members
Family functioning differences across the deployment cycle in British Army families: the perceptions of wives and children
Introduction
Military deployment can have an adverse effect on a soldier’s family, though little research has looked at these effects in a British sample. We investigated wives’ of UK serving soldiers perceptions of marital and family functioning, across three stages of the deployment cycle: currently deployed, post-deployment and pre-deployed, plus a non-military comparison group. Uniquely, young (aged 3.5 – 11 years) children’s perceptions of their family were also investigated, using the Parent-Child Alliance (PCA) coding scheme of drawings of the family.
Materials and Methods
Two hundred and twenty British military families of regular service personnel from the British Army’s Royal Armoured Corps (RAC), were sent survey packs distributed with a monthly welfare office newsletter. Wives were asked to complete a series of self-report items, and the youngest child in the family between the ages of 3.5 and 11 years was asked to draw a picture of their family. Complete data were available for 78 military families, and an additional 34 non-military families were recruited via opportunity sampling.
Results
Results indicated wives of currently deployed and recently returned personnel were less satisfied with their family and its communication, and children’s pictures indicated higher levels of dysfunctional PCA, whilst pre-deployed families responded similarly to non-military families. Marital satisfaction was similar across all groups except pre-deployed families who were significantly more satisfied. Non-military and pre-deployed families showed balanced family functioning, and currently and recently deployed families demonstrated poor family functioning. In comparison to non-military families, pre-deployed families showed a large ‘spike’ in the rigidity subscale of the FACES IV.
Conclusion
Wives’ perceptions of family functioning, but not marital satisfaction, differed between the deployment groups. The results from the coded children’s drawings correlated with the self-report measures from the wife/mother, indicating that children’s drawings could be a useful approach when working with younger children in this area.
It is tentatively suggested that the differences across deployment stage on family functioning could be mediated not only by communication difficulties between deployed personnel and their families, but also by its effect on the children in the family. Larger-scale longitudinal research is needed to investigate this further
Minimal size of a barchan dune
Barchans are dunes of high mobility which have a crescent shape and propagate
under conditions of unidirectional wind. However, sand dunes only appear above
a critical size, which scales with the saturation distance of the sand flux [P.
Hersen, S. Douady, and B. Andreotti, Phys. Rev. Lett. {\bf{89,}} 264301 (2002);
B. Andreotti, P. Claudin, and S. Douady, Eur. Phys. J. B {\bf{28,}} 321 (2002);
G. Sauermann, K. Kroy, and H. J. Herrmann, Phys. Rev. E {\bf{64,}} 31305
(2001)]. It has been suggested by P. Hersen, S. Douady, and B. Andreotti, Phys.
Rev. Lett. {\bf{89,}} 264301 (2002) that this flux fetch distance is itself
constant. Indeed, this could not explain the proto size of barchan dunes, which
often occur in coastal areas of high litoral drift, and the scale of dunes on
Mars. In the present work, we show from three dimensional calculations of sand
transport that the size and the shape of the minimal barchan dune depend on the
wind friction speed and the sand flux on the area between dunes in a field. Our
results explain the common appearance of barchans a few tens of centimeter high
which are observed along coasts. Furthermore, we find that the rate at which
grains enter saltation on Mars is one order of magnitude higher than on Earth,
and is relevant to correctly obtain the minimal dune size on Mars.Comment: 11 pages, 10 figure
Searching for highly obscured AGN in the XMM-Newton serendipitous source catalog
The majority of active galactic nuclei (AGN) are obscured by large amounts of
absorbing material that makes them invisible at many wavelengths. X-rays, given
their penetrating power, provide the most secure way for finding these AGN. The
XMM-Newton serendipitous source catalog is the largest catalog of X-ray sources
ever produced; it contains about half a million detections. These sources are
mostly AGN. We have derived X-ray spectral fits for very many 3XMM-DR4 sources
( 114 000 observations, corresponding to 77 000 unique
sources), which contain more than 50 source photons per detector. Here, we use
a subsample of 1000 AGN in the footprint of the SDSS area (covering
120 deg) with available spectroscopic redshifts. We searched for highly
obscured AGN by applying an automated selection technique based on X-ray
spectral analysis that is capable of efficiently selecting AGN. The selection
is based on the presence of either a) flat rest-frame spectra; b) flat observed
spectra; c) an absorption turnover, indicative of a high rest-frame column
density; or d) an Fe K line with an equivalent width > 500 eV. We found
81 highly obscured candidate sources. Subsequent detailed manual spectral fits
revealed that 28 of them are heavily absorbed by column densities higher than
10 cm. Of these 28 AGN, 15 are candidate Compton-thick AGN on the
basis of either a high column density, consistent within the 90% confidence
level with N 10 cm, or a large equivalent width
(>500 eV) of the Fe K line. Another six are associated with
near-Compton-thick AGN with column densities of 510
cm. A combination of selection criteria a) and c) for low-quality
spectra, and a) and d) for medium- to high-quality spectra, pinpoint highly
absorbed AGN with an efficiency of 80%.Comment: 18 pages, 10 figures, accepted for publication in A&
Spatially-resolved Thermal Continuum Absorption against the Supernova Remnant W49B
We present sub-arcminute resolution imaging of the Galactic supernova remnant
W49B at 74 MHz (25") and 327 MHz (6"), the former being the lowest frequency at
which the source has been resolved. While the 327 MHz image shows a shell-like
morphology similar to that seen at higher frequencies, the 74 MHz image is
considerably different, with the southwest region of the remnant almost
completely attenuated. The implied 74 MHz optical depth (~ 1.6) is much higher
than the intrinsic absorption levels seen inside two other relatively young
remnants, Cas A and the Crab Nebula, nor are natural variations in the
relativistic electron energy spectra expected at such levels. The geometry of
the absorption is also inconsistent with intrinsic absorption. We attribute the
absorption to extrinsic free-free absorption by a intervening cloud of thermal
electrons. Its presence has already been inferred from the low-frequency
turnover in the integrated continuum spectrum and from the detection of radio
recombination lines toward the remnant. Our observations confirm the basic
conclusions of those measurements, and our observations have resolved the
absorber into a complex of classical HII regions surrounded either partially or
fully by low-density HII gas. We identify this low-density gas as an extended
HII region envelope (EHE), whose statistical properties were inferred from low
resolution meter- and centimeter-wavelength recombination line observations.
Comparison of our radio images with HI and H_2CO observations show that the
intervening thermal gas is likely associated with neutral and molecular
material as well.Comment: 18 pages, LaTeX with AASTeX-5, 5 figures in 7 PostScript files;
accepted for publication in the Ap
Managing ovarian hyperstimulation syndrome: a qualitative interview study with women and healthcare professionals
To explore the experiences of women who have had ovarian hyperstimulation syndrome, and healthcare professionals who care for them.
Background
Ovarian hyperstimulation syndrome is a side effect of fertility treatment. Little research exists internationally that explores the experiences of women who have had this condition, or the healthcare professionals who manage it.
Design
Qualitative study using semi-structured interviews.
Methods
Eighteen interviews with women who had experienced ovarian hyperstimulation syndrome (n = 10) and healthcare professionals (n = 8) in six UK fertility centres. Framework analysis was used. This paper is reported following COREQ guidelines.
Results
Women described a range of symptoms and severity, sometimes experiencing worrying physical health problems such as abdominal swelling and shortness of breath. The combination of the symptoms, and their management, on delaying future fertility treatment could cause emotional distress. Healthcare professionals at different centres described variation in practice, which generally involved ‘active monitoring’ until symptoms became severe, when women would be hospitalised. Women expressed feeling ‘left in limbo’ while waiting for symptoms to improve or worsen, and described a lack of control during this waiting period. Healthcare professionals felt they provided adequate information about ovarian hyperstimulation syndrome and its management. This, however, did not align with women's perceptions that information, including potential delays to their fertility treatment, was missing. There was similar mismatch between women's and healthcare professionals' views of decision-making about fertility treatment following ovarian hyperstimulation syndrome, including women's concerns about having to make rushed, unplanned decisions about their fertility treatment when they did not feel adequately informed to do so.
Conclusion
Ovarian hyperstimulation syndrome and its management can have a significant physical and emotional impact on women, and influence their fertility treatment. Improvements could be made to the information women receive about this condition, its management and its implications for wider fertility treatment.
Implications for the profession and/or patient care
Nurses have the skills and knowledge to support women through the physical and emotional stresses of fertility treatment. Therefore, they are well placed to provide specialist information and support for OHSS and ensure women are fully informed about all aspects of the condition, including how its management might delay fertility treatment
Biogenic crust dynamics on sand dunes
Sand dunes are often covered by vegetation and biogenic crusts. Despite their
significant role in dune stabilization, biogenic crusts have rarely been
considered in studies of dune dynamics. Using a simple model, we study the
existence and stability ranges of different dune-cover states along gradients
of rainfall and wind power. Two ranges of alternative stable states are
identified: fixed crusted dunes and fixed vegetated dunes at low wind power,
and fixed vegetated dunes and active dunes at high wind power. These results
suggest a cross-over between two different forms of desertification
Simulating JWST deep extragalactic imaging surveys and physical parameter recovery
International audienceWe present a new prospective analysis of deep multi-band imaging with the James Webb Space Telescope (JWST). In this work, we investigate the recovery of high-redshift 5  6 and redshifts of 0   5 galaxy samples can be reduced to < 0.01 arcmin−2 with a limited impact on galaxy completeness. We investigate multiple high-redshift galaxy selection techniques and find that the best compromise between completeness and purity at 5 <  z <  10 using the full redshift posterior probability distributions. In the EGS field, the galaxy completeness remains higher than 50% at magnitudes mUV <  27.5 and at all redshifts, and the purity is maintained above 80 and 60% at z ≤ 7 and 10, respectively. The faint-end slope of the galaxy UV luminosity function is recovered with a precision of 0.1–0.25, and the cosmic star formation rate density within 0.1 dex. We argue in favor of additional observing programs covering larger areas to better constrain the bright end
A Continuum Saltation Model for Sand Dunes
We derive a phenomenological continuum saltation model for aeolian sand
transport that can serve as an efficient tool for geomorphological
applications. The coupled differential equations for the average density and
velocity of sand in the saltation layer reproduce both known equilibrium
relations for the sand flux and the time evolution of the sand flux as
predicted by microscopic saltation models. The three phenomenological
parameters of the model are a reference height for the grain-air interaction,
an effective restitution coefficient for the grain-bed interaction, and a
multiplication factor characterizing the chain reaction caused by the impacts
leading to a typical time or length scale of the saturation transients. We
determine the values of these parameters by comparing our model with wind
tunnel measurements. Our main interest are out of equilibrium situations where
saturation transients are important, for instance at phase boundaries
(ground/sand) or under unsteady wind conditions. We point out that saturation
transients are indispensable for a proper description of sand flux over
structured terrain, by applying the model to the windward side of an isolated
dune, thereby resolving recently reported discrepancies between field
measurements and theoretical predictions.Comment: 11 pages, 7 figure
A two-species continuum model for aeolian sand ripples
We formulate a continuum model for aeolian sand ripples consisting of two
species of grains: a lower layer of relatively immobile clusters, with an upper
layer of highly mobile grains moving on top. We predict analytically the ripple
wavelength, initial ripple growth rate and threshold saltation flux for ripple
formation. Numerical simulations show the evolution of realistic ripple
profiles from initial surface roughness via ripple growth and merger.Comment: 9 pages, 3 figure
X-ray Source Populations in the Region of the Open Clusters NGC 6633 and IC 4756
Using deep exposures (~10^5 s) with the ROSAT HRI, we have performed
flux-limited surveys for X-ray sources in the vicinity of the Hyades-age open
stellar clusters NGC 6633 and IC 4756, detecting 31 and 13 sources
respectively. Our primary aim is to search for so-far unrecognised cluster
members. We propose identifications or classifications (cluster member, field
star, extragalactic field object) for the X-ray sources, based on published
membership lists, and on X-ray:optical flux ratios and optical
colour--magnitude diagrams. Results of simulating the expected X-ray-emitting
source populations are compared with the ROSAT measurements and with the
expected capabilities of the XMM mission. The simulations provide a novel
method of comparing the activity levels of NGC 6633 and IC 4756 with that of
the Hyades. The measurements and simulations confirm that cluster members are
the major class of X-ray emitter in these fields at flux levels f_x >
10^{-14}/erg/cm^2/s (0.1--2.4 keV), contributing ~40 per cent of the total
X-ray sources. We find 6 possible new members in NGC 6633, and 4 candidates in
IC 4756; all require further observation to establish membership probability.Comment: 12 pages, 4 figure
- …