1,362 research outputs found
Differentiating patterns of violence in the family
The feasibility and prevalence of Reciprocal, Hierarchical and Paternal patterns of family aggression hypothesised by Dixon and Browne (2003) were explored within a sample of maltreating families. The psychological reports of 67 families referred to services for alleged child maltreatment that evidenced concurrent physical intimate partner violence and child maltreatment were investigated. Of these, 29 (43.3%) cases were characterised by hierarchical; 28 (41.8%) Reciprocal and 10 (14.9%) Paternal patterns. Significant differences in the form of child maltreatment perpetrated by mothers and fathers and parent dyads living in different patterns were found. In Hierarchical sub-patterns, fathers were significantly more likely to have been convicted for a violent and/or sexual offence than mothers and were significantly less likely to be biologically related to the child. The findings demonstrate the existence of the different patterns in a sample of families involved in the Child Care Protection process in England and Wales, supporting the utility of a holistic approach to understanding aggression in the family
The joint evolution of baryons and dark matter haloes
We have studied the dark matter (DM) distribution in a approx 10^12 h^-1
M_sun mass halo extracted from a simulation consistent with the concordance
cosmology, where the physics regulating the transformation of gas into stars
was allowed to change producing galaxies with different morphologies. The
presence of baryons produces the concentration of the DM halo with respect to
its corresponding dissipationless run, but we found that this response does not
only depend on the amount of baryons gathered in the central region but also on
the way they have been assembled. DM and baryons affect each other in a complex
way so the formation history of a galaxy plays an important role on its final
total mass distribution. Supernova (SN) feedback regulates the star formation
and triggers galactic outflows not only in the central galaxy but also in its
satellites. Our results suggest that, as the effects of SN feedback get
stronger, satellites get less massive and can even be more easily disrupted by
dynamical friction, transferring less angular momentum. We found indications
that this angular momentum could be acquired not only by the outer part of the
DM halo but also by the inner ones and by the stellar component in the central
galaxy. The latter effect produces stellar migration which contributes to
change the inner potential well, probably working against further DM
contraction. As a consequence of the action of these processes, when the halo
hosts a galaxy with an important disc structure formed by smooth gas accretion,
it is more concentrated than when it hosts a spheroidal system which
experienced more massive mergers and interactions. (abridged)Comment: 16 pages, 16 figures, accepted to MNRA
Experiments on Multidimensional Solitons
This article presents an overview of experimental efforts in recent years
related to multidimensional solitons in Bose-Einstein condensates. We discuss
the techniques used to generate and observe multidimensional nonlinear waves in
Bose-Einstein condensates with repulsive interactions. We further summarize
observations of planar soliton fronts undergoing the snake instability, the
formation of vortex rings, and the emergence of hybrid structures.Comment: review paper, to appear as Chapter 5b in "Emergent Nonlinear
Phenomena in Bose-Einstein Condensates: Theory and Experiment," edited by P.
G. Kevrekidis, D. J. Frantzeskakis, and R. Carretero-Gonzalez
(Springer-Verlag
Galaxy-Induced Transformation of Dark Matter Halos
We use N-body/gasdynamical LambdaCDM cosmological simulations to examine the
effect of the assembly of a central galaxy on the shape and mass profile of its
dark halo. Two series of simulations are compared; one that follows only the
evolution of the dark matter component and a second one where a baryonic
component is added. These simulations include radiative cooling but neglect
star formation and feedback, leading most baryons to collect at the halo center
in a disk which is too small and too massive when compared with typical spiral.
This unrealistic model allows us, nevertheless, to gauge the maximum effect
that galaxies may have in transforming their dark halos. We find that the shape
of the halo becomes more axisymmetric: halos are transformed from triaxial into
essentially oblate systems, with well-aligned isopotential contours of roughly
constant flattening (c/a ~ 0.85). Halos always contract as a result of galaxy
assembly, but the effect is substantially less pronounced than predicted by the
"adiabatic contraction" hypothesis. The reduced contraction helps to reconcile
LambdaCDM halos with constraints on the dark matter content inside the solar
circle and should alleviate the long-standing difficulty of matching
simultaneously the scaling properties of galaxy disks and the luminosity
function. The halo contraction is also less pronounced than found in earlier
simulations, a disagreement that suggests that halo contraction is not solely a
function of the initial and final distribution of baryons. Not only how much
baryonic mass has been deposited at the center of a halo matters, but also the
mode of its deposition. It might prove impossible to predict the halo response
without a detailed understanding of a galaxy's assembly history. (Abriged)Comment: 11 pages and 9 figure
The DEEP2 Galaxy Redshift Survey: The Voronoi-Delaunay Method Catalog of Galaxy Groups
We present a public catalog of galaxy groups constructed from the spectroscopic sample of galaxies in the fourth data release from the Deep Extragalactic Evolutionary Probe 2 (DEEP2) Galaxy Redshift Survey, including the Extended Groth Strip (EGS). The catalog contains 1165 groups with two or more members in the EGS over the redshift range 0 0.6 in the rest of DEEP2. Twenty-five percent of EGS galaxies and fourteen percent of high-z DEEP2 galaxies are assigned to galaxy groups. The groups were detected using the Voronoi-Delaunay method (VDM) after it has been optimized on mock DEEP2 catalogs following similar methods to those employed in Gerke et al. In the optimization effort, we have taken particular care to ensure that the mock catalogs resemble the data as closely as possible, and we have fine-tuned our methods separately on mocks constructed for the EGS and the rest of DEEP2. We have also probed the effect of the assumed cosmology on our inferred group-finding efficiency by performing our optimization on three different mock catalogs with different background cosmologies, finding large differences in the group-finding success we can achieve for these different mocks. Using the mock catalog whose background cosmology is most consistent with current data, we estimate that the DEEP2 group catalog is 72% complete and 61% pure (74% and 67% for the EGS) and that the group finder correctly classifies 70% of galaxies that truly belong to groups, with an additional 46% of interloper galaxies contaminating the catalog (66% and 43% for the EGS). We also confirm that the VDM catalog reconstructs the abundance of galaxy groups with velocity dispersions above ~300 km s^(–1) to an accuracy better than the sample variance, and this successful reconstruction is not strongly dependent on cosmology. This makes the DEEP2 group catalog a promising probe of the growth of cosmic structure that can potentially be used for cosmological tests
Spatial patterns of scour and fill in dryland sand bed streams
Reproduced with permission of the publisher. © 2006 American Geophysical UnionSpatial patterns of scour and fill in two dryland ephemeral stream channels with sandy bed material have been measured with dense arrays of scour chains. Although the depth and areal extent of bed activity increased with discharge, active bed reworking at particular locations within the reaches resulted in downstream patterns of alternate shallower and deeper areas of scour. The variation was such that mean scour depths for individual cross sections varied about the mean for the reach by a factor of 2–4 while the locus of maximum scour traced a sinuous path about the channel centerline. The wavelength of the pattern of scour was about seven times the channel width. During each event, compensating fill returned the streambeds to preflow elevations, indicating that the streams were in approximate steady state over the period of study. Although the patterns of periodically enhanced scour along alternate sides of the channels are consistent with models of periodically reversing helical flow, further work is required to identify the causal relationships between patterns of flow and sediment transport in dryland sand bed channels
The Baryonic Assembly of Dark Matter Halos
We use a suite of cosmological hydrodynamic simulations to quantify the
accretion rates of baryons into dark matter halos and the resulting baryon mass
fractions, as a function of halo mass, redshift, and baryon type (including
cold and hot gas). We find that the net baryonic accretion rates through the
virial radius are sensitive to galactic outflows and explore a range of outflow
parameters to illustrate the effects. We show that the cold gas accretion rate
is in general not a simple universal factor of the dark matter accretion rate,
and that galactic winds can cause star formation rates to deviate significantly
from the external gas accretion rates, both via gas ejection and re-accretion.
Furthermore, galactic winds can inject enough energy and momentum in the
surrounding medium to slow down accretion altogether, especially in low-mass
halos and at low redshift. By resolving the accretion rates versus radius from
the halo centers, we show how cold streams penetrate the hot atmospheres of
massive halos at z>2, but gradually disappear at lower redshift. The total
baryon mass fraction is also strongly suppressed by outflows in low-mass halos,
but is nearly universal in the absence of feedback in halos above the UV
background suppression scale. The transition halo mass, at which the gas mass
in halos is equal for the cold and hot components, is roughly constant at
~10^11.5 Msun and does not depend sensitively on the wind prescription. We
provide simple fitting formulae for the cold gas accretion rate into halos in
the no-wind case. Finally, we show that cold accretion is broadly consistent
with driving the bulk of the highly star-forming galaxies observed at z~2, but
that the more intense star formers likely sample the high end of the accretion
rate distribution, and may be additionally fueled by a combination of gas
recycling, gas re-accretion, hot mode cooling, and mergers.Comment: 20 pages, 10 figures. MNRAS, in pres
The impact of physical, psychological, and sexual intimate partner violence on women's mental health: depressive symptoms, posttraumatic stress disorder, state anxiety, and suicide
Objective: This study aimed to determine the impact of lifetime physical, psychological, and
sexual intimate male partner violence (IPV) on the mental health of women, after controlling
for the contribution of lifetime victimization. The comorbidity of depressive symptoms and
posttraumatic stress disorder (PTSD) and their relation to state anxiety and suicide were also
assessed.
Methods: Physically/psychologically (n 75) and psychologically abused women (n 55)
were compared with nonabused control women (n 52). Information about sociodemographic
characteristics, lifetime victimization, and mental health status (depressive and state anxiety
symptoms, PTSD, and suicide) was obtained through face-to-face structured interviews.
Results: Women exposed to physical/psychological and psychological IPV had a higher incidence
and severity of depressive and anxiety symptoms, PTSD, and thoughts of suicide than
control women, with no differences between the two abused groups. The concomitance of
sexual violence was associated with a higher severity of depressive symptoms in both abused
groups and a higher incidence of suicide attempts in the physically/psychologically abused
group. The incidence of PTSD alone was very rare, and depressive symptoms were either
alone or comorbid with PTSD. The severity of state anxiety was higher in abused women
with depressive symptoms or comorbidity, as was the incidence of suicidal thoughts in the
physically/psychologically abused group. Lifetime victimization was not a predictor of the
deterioration of mental health in this study.
Conclusions: These findings indicate that psychological IPV is as detrimental as physical
IPV, with the exception of effects on suicidality, which emphasizes that psychological IPV
should be considered a major type of violence by all professionals involved.Este es un artículo ampliamente citado internacionalmente respeto a violencia de pareja y consecuencias en la salud de las mujeres
Cardiosphere-derived cells suppress allogeneic lymphocytes by production of PGE2 acting via the EP4 receptor
derived cells (CDCs) are a cardiac progenitor cell population, which have been shown to possess cardiac regenerative properties and can improve heart function in a variety of cardiac diseases. Studies in large animal models have predominantly focussed on using autologous cells for safety, however allogeneic cell banks would allow for a practical, cost-effective and efficient use in a clinical setting. The aim of this work was to determine the immunomodulatory status of these cells using CDCs and lymphocytes from 5 dogs. CDCs expressed MHC I but not MHC II molecules and in mixed lymphocyte reactions demonstrated a lack of lymphocyte proliferation in response to MHC-mismatched CDCs. Furthermore, MHC-mismatched CDCs suppressed lymphocyte proliferation and activation in response to Concanavalin A. Transwell experiments demonstrated that this was predominantly due
to direct cell-cell contact in addition to soluble mediators whereby CDCs produced high levels of PGE2
under inflammatory conditions. This led to down-regulation of CD25 expression on lymphocytes via the
EP4 receptor. Blocking prostaglandin synthesis restored both, proliferation and activation (measured via CD25 expression) of stimulated lymphocytes. We demonstrated for the first time in a large animal model that CDCs inhibit proliferation in allo-reactive lymphocytes and have potent immunosuppressive activity mediated via PGE2
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Elastic and anelastic relaxation behaviour of perovskite multiferroics II: PbZrTiO (PZT)–PbFeTaO (PFT)
Elastic and anelastic properties of ceramic samples of multiferroic perovskites with nominal compositions across the binary join PbZrTiO–PbFeTaO (PZT–PFT) have been assembled to create a binary phase diagram and to address the role of strain relaxation associated with their phase transitions. Structural relationships are similar to those observed previously for PbZrTiO–PbFeNbO (PZT–PFN), but the magnitude of the tetragonal shear strain associated with the ferroelectric order parameter appears to be much smaller. This leads to relaxor character for the development of ferroelectric properties in the end member PbFeTaO. As for PZT–PFN, there appear to be two discrete instabilities rather than simply a reorientation of the electric dipole in the transition sequence cubic–tetragonal–monoclinic, and the second transition has characteristics typical of an improper ferroelastic. At intermediate compositions, the ferroelastic microstructure has strain heterogeneities on a mesoscopic length scale and, probably, also on a microscopic scale. This results in a wide anelastic freezing interval for strain-related defects rather than the freezing of discrete twin walls that would occur in a conventional ferroelastic material. In PFT, however, the acoustic loss behaviour more nearly resembles that due to freezing of conventional ferroelastic twin walls. Precursor softening of the shear modulus in both PFT and PFN does not fit with a Vogel–Fulcher description, but in PFT there is a temperature interval where the softening conforms to a power law suggestive of the role of fluctuations of the order parameter with dispersion along one branch of the Brillouin zone. Magnetic ordering appears to be coupled only weakly with a volume strain and not with shear strain but, as with multiferroic PZT–PFN perovskites, takes place within crystals which have significant strain heterogeneities on different length scales.RUS facilities in Cambridge were established with funding from the Natural Environment Research Council (Grants NE/B505738/1, NE/F017081/1). The present work was supported by Grant No. EP/ I036079/1 from the Engineering and Physical Sciences Research Council. We thank Dr. Sam Crossley for his assistance with dielectric analysis and the use of his software to run those measurements. JAS gratefully acknowledges the hospitality of the Max Planck Institute for Chemical Physics of Solids. The Nanopaleomagnetism lab has received funding from the European Research Council under the European Union’s Seventh Framework Programme (FP/2007– 2013)/ERC Grant Agreement 320750. SED and HS acknowledge support from the Winton Programme for the physics of sustainability. HS also acknowledges support from the Funai Foundation for Information Technology and the British Council Japan Association. Part of the work was carried out at the University of Puerto Rico, supported by the DOEEBSCoR project DEG02-ER46526
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