5,811 research outputs found
Clinical Associations of Deliberate Self-Injury and Its Impact on the Outcome of Community-Based and Long-Term Inpatient Treatment for Personality Disorder
Background: Deliberate self-injury (DSI) is significantly associated with personality disorder (PD). There are gaps in our knowledge of DSI as an indicator of severity of psychopathology, as moderator of outcome and with regard to its response to different treatment programs and settings. Methods: We compare 2 samples of PD with (n = 59) and without (n = 64) DSI in terms of clinical presentation, response to psychosocial treatment and relative outcome when treated with specialist long-term residential and community-based programs. We test the assumption that DSI is an appropriate indicator for long-term inpatient care by contrasting the outcomes (symptom severity and DSI recidivism) of the 2 DSI sub-groups treated in the 2 different approaches. Results: PD with DSI had greater severity of presentation on a number of variables (early maternal separation, sexual abuse, axis-I comorbidities, suicidality and inpatient episodes) than PD without DSI. With regard to treatment response, we found a significant 3-way interaction between DSI, treatment model and outcome at 24-month follow-up. PD with DSI treated in a community-based program have significantly greater chances of improving on symptom severity and recidivism of self-injurious behaviour compared to PD with DSI treated in a long-term residential program. Conclusions: Although limitations in the study design invite caution in interpreting the results, the poor outcome of the inpatient DSI group suggests that explicit protocols for the management of DSI in inpatient settings may be beneficial and that the clinical indications for long-term inpatient treatment for severe and non-severe PD may require updating. Copyright (C) 2010 S. Karger AG, Base
Optimized Confinement of Fermions in Two Dimensions
One of the challenging features of studying model Hamiltonians with cold
atoms in optical lattices is the presence of spatial inhomogeneities induced by
the confining potential, which results in the coexistence of different phases.
This paper presents Quantum Monte Carlo results comparing meth- ods for
confining fermions in two dimensions, including conventional diagonal
confinement (DC), a recently proposed 'off-diagonal confinement' (ODC), as well
as a trap which produces uniform den- sity in the lattice. At constant entropy
and for currently accessible temperatures, we show that the current DC method
results in the strongest magnetic signature, primarily because of its judicious
use of entropy sinks at the lattice edge. For d-wave pairing, we show that a
constant density trap has the more robust signal and that ODC can implement a
constant density profile. This feature is important to any prospective search
for superconductivity in optical lattices
The Finite Size Error in Many-body Simulations with long-Ranged Interactions
We discuss the origin of the finite size error of the energy in many-body
simulation of systems of charged particles and we propose a correction based on
the random phase approximation at long wave lengths. The correction comes from
contributions mainly determined by the organized collective oscillations of the
interacting system. Finite size corrections, both on kinetic and potential
energy, can be calculated within a single simulation. Results are presented for
the electron gas and silicon.Comment: 4 pages, 4 figures, submitted to PRL; corrected typo
The relevance of hydroxyapatite and spongious titanium coatings in fixation of cementless stems. An experimental comparative study in rat femur employing histological and microangiographic techniques.
Pure titanium rods plasma-spray coated with hydroxyapatite (HA) or porous titanium (Ti) of controlled roughness were implanted bilaterally in the distal femur of Sprague-Dawley rats to compare the extent of bone growth on the two types of coating. The relevance of other factors, like mechanical stability and biological adaptation of the bone to the insertion of a foreign body implant, were investigated in femora which were over-reamed (absence of primary fit) or reamed without insertion of the rod. Continuous tetracycline labeling for the first 30 days and for the last 2 weeks in the 90-day group was performed; histological/histometric, fluorescence and microangiographic studies were carried out on serial sections of the implanted and control femora. In the group of stable implants, HA-coated rods showed 90% integration versus 53% with Ti-coated implants (P < 0.001); in over-reamed implants neither surface bone growth nor endosteal fixation occurred, and both types of rods were surrounded by a thick layer of connective tissue. The study documented early adhesion of osteoblasts and direct deposition of bone matrix on the substrate, while on spongious titanium osteogenesis was observed only in proximity to the surface. Remodeling of the reactive, primary bone to mature, lamellar bone took the form of a capsule surrounding the implants and radial bridges connecting the latter to the endosteal surface. The number, height and thickness of these bridges appeared to be the factors determining implant stability, rather than the extent of the bony capsule on the perimeter of the implant. Integration was a function not only of mechanical conditions and surface geometry, but also of the biological response of the whole bone to changes in the vascularization pattern. The reported phenomena can be seen more easily in experimental models involving small rodents because of their fast bone turnover and revascularization, but it is expected that they take place, even at a lower speed, in clinical situations like cementless stems of total hip replacement
Lying Your Way to Better Traffic Engineering
To optimize the flow of traffic in IP networks, operators do traffic
engineering (TE), i.e., tune routing-protocol parameters in response to traffic
demands. TE in IP networks typically involves configuring static link weights
and splitting traffic between the resulting shortest-paths via the
Equal-Cost-MultiPath (ECMP) mechanism. Unfortunately, ECMP is a notoriously
cumbersome and indirect means for optimizing traffic flow, often leading to
poor network performance. Also, obtaining accurate knowledge of traffic demands
as the input to TE is elusive, and traffic conditions can be highly variable,
further complicating TE. We leverage recently proposed schemes for increasing
ECMP's expressiveness via carefully disseminated bogus information ("lies") to
design COYOTE, a readily deployable TE scheme for robust and efficient network
utilization. COYOTE leverages new algorithmic ideas to configure (static)
traffic splitting ratios that are optimized with respect to all (even
adversarially chosen) traffic scenarios within the operator's "uncertainty
bounds". Our experimental analyses show that COYOTE significantly outperforms
today's prevalent TE schemes in a manner that is robust to traffic uncertainty
and variation. We discuss experiments with a prototype implementation of
COYOTE
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Calculating quench propagation with ANSYS®
A commercial Finite-Element-Analysis program, ANSYS®, is widely used in structural and thermal analysis. With the program's ability to include nonlinear material properties and import complex CAD files, one can generate coil geometries and simulate quench propagation in superconducting magnets. A "proof-of-principle" finite element model was developed assuming a resistivity that increases linearly from zero to its normal value at a temperature consistent with the assumed B magnetic field. More sophisticated models could easily include finer-grained coil, cable, structural, and circuit details. A quench is provoked by raising the temperature of an arbitrary superconducting element above its T . The time response to this perturbation is calculated using small time-steps to allow convergence between steps. Snapshots of the temperature and voltage distributions allow examination of longitudinal and turn-to-turn quench propagation, quench-front annihilation, and cryo-stability. Modeling details are discussed, and a computed voltage history was compared with measurements from a recent magnet test.
Critiquing Variational Theories of the Anderson-Hubbard Model: Real-Space Self-Consistent Hartree-Fock Solutions
A simple and commonly employed approximate technique with which one can
examine spatially disordered systems when strong electronic correlations are
present is based on the use of real-space unrestricted self-consistent
Hartree-Fock wave functions. In such an approach the disorder is treated
exactly while the correlations are treated approximately. In this report we
critique the success of this approximation by making comparisons between such
solutions and the exact wave functions for the Anderson-Hubbard model. Due to
the sizes of the complete Hilbert spaces for these problems, the comparisons
are restricted to small one-dimensional chains, up to ten sites, and a 4x4
two-dimensional cluster, and at 1/2 filling these Hilbert spaces contain about
63,500 and 166 million states, respectively. We have completed these
calculations both at and away from 1/2 filling. This approximation is based on
a variational approach which minimizes the Hartree-Fock energy, and we have
completed comparisons of the exact and Hartree-Fock energies. However, in order
to assess the success of this approximation in reproducing ground-state
correlations we have completed comparisons of the local charge and spin
correlations, including the calculation of the overlap of the Hartree-Fock wave
functions with those of the exact solutions. We find that this approximation
reproduces the local charge densities to quite a high accuracy, but that the
local spin correlations, as represented by , are not as well
represented. In addition to these comparisons, we discuss the properties of the
spin degrees of freedom in the HF approximation, and where in the
disorder-interaction phase diagram such physics may be important
Categorical and dimensional approaches in the evaluation of the relationship between attachment and personality disorders: An empirical study
Although several studies have highlighted the relationship between attachment states of mind and personality disorders (PD), their findings have not been consistent, possibly due to the application of the traditional taxonomic classification model of attachment. A more recently developed dimensional classification of attachment representations, including more specific aspects of trauma-related representations, may have advantages. In this study we compare specific associations and predictive power of the categorical attachment and dimensional models applied to 230 Adult Attachment Interview transcripts obtained from personality disordered and non-psychiatric subjects. We also investigate the role that current levels of psychiatric distress may have in the prediction of PD. The results showed that both models predict the presence of PD, with the dimensional approach doing better in discriminating overall diagnosis of PD. However, both models are less helpful in discriminating specific PD diagnostic subtypes. Current psychiatric distress was found to be the most consistent predictor of PD capturing a large share of the variance and obscuring the role played by attachment variables. The results suggest that attachment parameters correlate with the presence of PD alone and has no specific associations with particular PD subtypes when current psychiatric distress is taken into account
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