5,110 research outputs found
Integrating research with NHS clinical practice: Unwelcome intrusion or constructive triangulation?
When embarking on research into the effectiveness of psychoanalytic psychotherapy in the NHS or the application of psychoanalytic principles, researchers come up against a number of hurdles: many clinicians still see empirical research as antithetical or disruptive to the practice of psychoanalytic psychotherapy; psychoanalytic psychotherapy has previously fared poorly in evidence-based policy guidelines and this can discourage ambition, and there are technical problems of research design, measurement and standardization. Nevertheless, in a political climate which stresses service evaluation, measurable outcomes and empirical evidence, psychoanalytic psychotherapy must participate to survive. There may be gains from conducting research beyond simply meeting the requirement to provide evidence of effectiveness. Research may be viewed by some clinicians as an unwelcome intruder but it may have the potential to offer triangulation, the perspective of the 'third', and so strengthen the foundations of clinical practice and the development of psychoanalytic thought
Lensing by Lyman Limit Systems: Determining the Mass to Gas Ratio
We present a new method to determine the total mass-to-neutral gas ratio in
Lyman-limits systems. The method exploits the relation between the neutral
hydrogen column density and the magnification of background sources due to the
weak gravitational lensing that these systems induce. Because weak lensing does
not provide a direct measure of mass, one must use this relation in a
statistical sense to solve for the average mass-to-gas ratio and its
distribution. We use a detailed mock catalog of quasars (sources) and
Lyman-limit systems (lenses) to demonstrate the applicability of this approach
through our ability to recover the parameter. This mock catalog also allows us
to check for systematics in the method and to sketch its limitations. For a
universal constant mass-to-gas ratio and a sample of N quasars, we obtain an
unbiased estimate of its value with 95% confidence limits (independent of its
actual value) of +/- 140 {10^5/N)^0.5.Comment: 20 pages, 11 figures submitted to Ap
Cosmological Implications of Lyman-Break Galaxy Clustering
We review our analysis of the clustering properties of ``Lyman-break''
galaxies (LBGs) at redshift z~3, previously discussed in Wechsler et al (1998).
We examine the likelihood of spikes found by Steidel et al (1998) in the
redshift distribution of LBGs, within a suite of models for the evolution of
structure in the Universe. Using high-resolution dissipationless N-body
simulations, we analyze deep pencil-beam surveys from these models in the same
way that they are actually observed, identifying LBGs with the most massive
dark matter halos. We find that all the models (with SCDM as a marginal
exception) have a substantial probability of producing spikes similar to those
observed, because the massive halos are much more clumped than the underlying
matter -- i.e., they are biased. Therefore, the likelihood of such a spike is
not a good discriminator among these models. The LBG correlation functions are
less steep than galaxies today (gamma~1.4), but show similar or slightly longer
correlation lengths. We have extened this analysis and include a preliminary
comparison to the new data presented in Adelberger et al (1998). We also
discuss work in progress, in which we use semi-analytic models to identify
Lyman-break galaxies within dark-matter halos.Comment: 4 pages, 2 figures, Latex, uses aipproc.sty; to appear in the
proceedings of the 9th Annual October Maryland Astrophysics Conference,
"After the Dark Ages: When the Galaxies Were Young (the Universe at 2<z<5)
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Characteristics of a cohort of high-risk men who have sex with men on pre-exposure prophylaxis reporting transgender sexual partners.
Transgender people continue to be at high-risk for HIV acquisition, but little is known about the characteristics of their sexual partners. To address this gap, we examined sociodemographic and sexual characteristics of cisgender men who have sex with men (MSM) on pre-exposure prophylaxis (PrEP) reporting transgender sexual partners.A cohort of 392 MSM in southern California in a randomized clinical trial for PrEP adherence were followed from 2013 to 2016. Multivariable generalized estimating equation and logistic models identified characteristics of MSM reporting transgender sexual partners and PrEP adherence.Only 14 (4%) MSM reported having transgender sexual partners. MSM were more likely to report transgender partners if they were African American, had incident chlamydia, reported injection drug-using sexual partners, or received items for sex. Most associations remained significant in the multivariable model: African American (adjusted odds ratio [AOR] 11.20, Pâ=â.01), incident chlamydia (AOR 3.71, Pâ=â.04), and receiving items for sex (AOR 5.29, Pâ=â.04). There were no significant differences in PrEP adherence between MSM reporting transgender partners and their counterpart.MSM who report transgender sexual partners share characteristics associated with individuals with high HIV prevalence. Identifying this group distinct from larger cohorts of MSM could offer new HIV prevention opportunities for this group of MSM and the transgender community
Additional femoral catheter in combination with popliteal catheter for analgesia after major ankle surgery
Background The contribution of the saphenous nerve in pain after major ankle surgery is unknown. The aim of this study was to evaluate its contribution in this context. Methods Fifty patients were included in this prospective, randomized, controlled study. In all patients [Group P (popliteal) and Group F (popliteal+femoral)], a popliteal catheter was placed before operation and ropivacaine 0.5% (30 ml) administered via this catheter; major ankle surgery was then performed under spinal anaesthesia. In Group PF patients, an additional femoral catheter was sited before operation and ropivacaine 0.5% (10 ml) administered. Six hours after spinal anaesthesia (defined as T0), a continuous infusion of ropivacaine 0.3% (14 ml hâ1) was started through the popliteal catheter until T24. Then, the concentration was reduced to 0.2% until T48. Patients in Group PF received continuous ropivacaine 0.2% (5 ml hâ1) through the femoral catheter from T0 to T48. I.V. morphine patient-controlled analgesia was used as a rescue analgesia. Pain at rest, pain with movement, adverse effects, and i.v. morphine consumption were assessed. Pain at rest and on movement was evaluated 6 months after operation. Results Pain at rest was comparable in the two groups. In Group PF, patients had significantly reduced pain during movement in the postoperative period (P=0.01) and 6 months after operation (P=0.03). Morphine consumption was significantly reduced in Group PF at T0-T24 and T24-T48 (P=0.01). Adverse effects were comparable in both groups. Conclusions The addition of continuous femoral catheter infusion of ropivacaine to a continuous popliteal catheter infusion improved postoperative analgesia during movement after major ankle surgery. This effect was still present 6 months after surger
A Causal Order for Spacetimes with Lorentzian Metrics: Proof of Compactness of the Space of Causal Curves
We recast the tools of ``global causal analysis'' in accord with an approach
to the subject animated by two distinctive features: a thoroughgoing reliance
on order-theoretic concepts, and a utilization of the Vietoris topology for the
space of closed subsets of a compact set. We are led to work with a new causal
relation which we call , and in terms of it we formulate extended
definitions of concepts like causal curve and global hyperbolicity. In
particular we prove that, in a spacetime \M which is free of causal cycles,
one may define a causal curve simply as a compact connected subset of \M
which is linearly ordered by . Our definitions all make sense for
arbitrary metrics (and even for certain metrics which fail to be
invertible in places). Using this feature, we prove for a general metric,
the familiar theorem that the space of causal curves between any two compact
subsets of a globally hyperbolic spacetime is compact. We feel that our
approach, in addition to yielding a more general theorem, simplifies and
clarifies the reasoning involved. Our results have application in a recent
positive energy theorem, and may also prove useful in the study of topology
change. We have tried to make our treatment self-contained by including proofs
of all the facts we use which are not widely available in reference works on
topology and differential geometry.Comment: Two small revisions to accomodate errors brought to our attention by
R.S. Garcia. No change to chief results. 33 page
Galaxy Formation at z~3: Constraints from Spatial Clustering
We use N-body simulations combined with semi-analytic models to compute the
clustering properties of modeled galaxies at z~3, and confront these
predictions with the clustering properties of the observed population of
Lyman-break galaxies (LBGs). Several scenarios for the nature of LBGs are
explored, which may be broadly categorized into models in which high-redshift
star formation is driven by collisional starbursts and those in which quiescent
star formation dominates. For each model, we make predictions for the LBG
overdensity distribution, the variance of counts-in-cells, the correlation
length, and close pair statistics. Models which assume a one-to-one
relationship between massive dark-matter halos and galaxies are disfavored by
close pair statistics, as are models in which colliding halos are associated
with galaxies in a simplified way. However, when modeling of gas consumption
and star formation is included using a semi-analytic treatment, the quiescent
and collisional starburst models predict similar clustering properties and none
of these models can be ruled out based on the available clustering data. None
of the ``realistic'' models predict a strong dependence of clustering amplitude
on the luminosity threshold of the sample, in apparent conflict with some
observational results.Comment: 20 pages, Latex, uses emulateapj5.sty, minor changes to match ApJ in
press versio
Topologically massive magnetic monopoles
We show that in the Maxwell-Chern-Simons theory of topologically massive
electrodynamics the Dirac string of a monopole becomes a cone in anti-de Sitter
space with the opening angle of the cone determined by the topological mass
which in turn is related to the square root of the cosmological constant. This
proves to be an example of a physical system, {\it a priory} completely
unrelated to gravity, which nevertheless requires curved spacetime for its very
existence. We extend this result to topologically massive gravity coupled to
topologically massive electrodynamics in the framework of the theory of Deser,
Jackiw and Templeton. These are homogeneous spaces with conical deficit. Pure
Einstein gravity coupled to Maxwell-Chern-Simons field does not admit such a
monopole solution
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