Treatment of psoriasis with cyclosporin

No Abstract

Competing density-wave orders in a one-dimensional hard-boson model

We describe the zero-temperature phase diagram of a model of bosons, occupying sites of a linear chain, which obey a hard-exclusion constraint: any two nearest-neighbor sites may have at most one boson. A special case of our model was recently proposed as a description of a ``tilted'' Mott insulator of atoms trapped in an optical lattice. Our quantum Hamiltonian is shown to generate the transfer matrix of Baxter's hard-square model. Aided by exact solutions of a number of special cases, and by numerical studies, we obtain a phase diagram containing states with long-range density-wave order with period 2 and period 3, and also a floating incommensurate phase. Critical theories for the various quantum phase transitions are presented. As a byproduct, we show how to compute the Luttinger parameter in integrable theories with hard-exclusion constraints.Comment: 16 page

Study protocol for a non-inferiority randomised controlled trial of SKY breathing meditation versus cognitive processing therapy for PTSD among veterans

Introduction Post-traumatic stress disorder (PTSD) is a debilitating, highly prevalent condition. Current clinical practice guidelines recommend trauma-focused psychotherapy (eg, cognitive processing therapy; CPT) as the first-line treatment for PTSD. However, while these treatments show clinically meaningful symptom improvement, the majority of those who begin treatment retain a diagnosis of PTSD post-treatment. Perhaps for this reason, many individuals with PTSD have sought more holistic, mind–body, complementary and integrative health (CIH) interventions. However, there remains a paucity of high-quality, active controlled efficacy studies of CIH interventions for PTSD, which precludes their formal recommendation. Methods and analyses We present the protocol for an ongoing non-inferiority parallel group randomised controlled trial (RCT) comparing the efficacy of a breathing meditation intervention (Sudarshan Kriya Yoga [SKY]) to a recommended evidence-based psychotherapy (CPT) for PTSD among veterans. Assessors are blinded to treatment group. The primary outcome measure is the PTSD Checklist-Civilian Version and a combination of clinical, self-report, experimental and physiological outcome measures assess treatment-related changes across each of the four PTSD symptom clusters (re-experiencing, avoidance, negative cognitions or mood and hyperarousal/reactivity). Once the RCT is completed, analyses will use both an intent-to-treat (using the ‘last observation carried forward’ for missing data) and a per-protocol or ‘treatment completers’ procedure, which is the most rigorous approach to non-inferiority designs. Ethics and dissemination To the best of our knowledge, this is this first non-inferiority RCT of SKY versus CPT for PTSD among veterans. The protocol is approved by the Stanford University Institutional Review Board. All participants provided written informed consent prior to participation. Results from this RCT will inform future studies including larger multi-site efficacy RCTs of SKY for PTSD and other mental health conditions, as well as exploration of cost-effectiveness and evaluation of implementation issues. Results will also inform evidence-based formal recommendations regarding CIH interventions for PTSD

Emotion dysregulation and heart rate variability improve in US veterans undergoing treatment for posttraumatic stress disorder: Secondary exploratory analyses from a randomised controlled trial

Background Emotion regulation (ER) is a key process underlying posttraumatic stress disorder (PTSD), yet, little is known about how ER changes with PTSD treatment. Understanding these effects may shed light on treatment processes. Methods We recently completed a non-inferiority design randomised controlled trial demonstrating that a breathing-based yoga practice (Sudarshan kriya yoga; SKY) was not clinically inferior to cognitive processing therapy (CPT) across symptoms of PTSD, depression, or negative affect. Here, in secondary exploratory analyses (intent-to-treat N = 85; per protocol N = 59), we examined whether self-reported ER (Difficulties in Emotion Regulation Scale; DERS) and physiological ER (heart rate variability; HRV) improved with treatment for clinically significant PTSD symptoms among US Veterans. Results DERS-Total and all six subscales improved with small-to-moderate effect sizes (d = .24–.66) following CPT or SKY, with no differences between treatment groups. Following SKY (but not CPT), HR max–min (average difference between maximum and minimum beats per minute), LF/HF (low-to-high frequency) ratio, and normalised HF-HRV (high frequency power) improved (moved towards a healthier profile; d = .42–.55). Conclusions To our knowledge, this is the first study to demonstrate that a breathing-based yoga (SKY) improved both voluntary/intentional and automatic/physiological ER. In contrast, trauma-focused therapy (CPT) only reliably improved self-reported ER. Findings have implications for PTSD treatment and interventions for emotional disorders more broadly. Trial registration Secondary analyses of ClinicalTrials.gov NCT02366403

An Exact Diagonalization Demonstration of Incommensurability and Rigid Band Filling for N Holes in the t-J Model

We have calculated S(q) and the single particle distribution function for N holes in the t - J model on a non--square sqrt{8} X sqrt{32} 16--site lattice with periodic boundary conditions; we justify the use of this lattice in compariosn to those of having the full square symmetry of the bulk. This new cluster has a high density of vec k points along the diagonal of reciprocal space, viz. along k = (k,k). The results clearly demonstrate that when the single hole problem has a ground state with a system momentum of vec k = (pi/2,pi/2), the resulting ground state for N holes involves a shift of the peak of the system's structure factor away from the antiferromagnetic state. This shift effectively increases continuously with N. When the single hole problem has a ground state with a momentum that is not equal to k = (pi/2,pi/2), then the above--mentioned incommensurability for N holes is not found. The results for the incommensurate ground states can be understood in terms of rigid--band filling: the effective occupation of the single hole k = (pi/2,pi/2) states is demonstrated by the evaluation of the single particle momentum distribution function . Unlike many previous studies, we show that for the many hole ground state the occupied momentum states are indeed k = (+/- pi/2,+/- pi/2) states.Comment: Revtex 3.0; 23 pages, 1 table, and 13 figures, all include

Small grid embeddings of 3-polytopes

We introduce an algorithm that embeds a given 3-connected planar graph as a convex 3-polytope with integer coordinates. The size of the coordinates is bounded by $O(2^{7.55n})=O(188^{n})$. If the graph contains a triangle we can bound the integer coordinates by $O(2^{4.82n})$. If the graph contains a quadrilateral we can bound the integer coordinates by $O(2^{5.46n})$. The crucial part of the algorithm is to find a convex plane embedding whose edges can be weighted such that the sum of the weighted edges, seen as vectors, cancel at every point. It is well known that this can be guaranteed for the interior vertices by applying a technique of Tutte. We show how to extend Tutte's ideas to construct a plane embedding where the weighted vector sums cancel also on the vertices of the boundary face

Direct Observation of a One Dimensional Static Spin Modulation in Insulating La1.95Sr0.05CuO4

We report the results of an extensive elastic neutron scattering study of the incommensurate (IC) static spin correlations in La1.95Sr0.05CuO4 which is an insulating spin glass at low temperatures. The present neutron scattering experiments on the same x=0.05 crystal employ a narrower instrumental Q-resolution and thereby have revealed that the crystal has only two orthorhombic twins at low temperatures with relative populations of 2:1. We find that, in a single twin, only two satellites are observed at (1, +/-0.064, L)(ortho) and (0, 1+/-0.064, L)(ortho), that is, the modulation vector is only along the orthorhombic b*-axis. This demonstrates unambiguously that La1.95Sr0.05CuO4 has a one-dimensional static diagonal spin modulation at low temperatures, consistent with certain stripe models. We have also reexamined the x=0.04 crystal that previously was reported to show a single commensurate peak. By mounting the sample in the (H, K, 0) zone, we have discovered that the x=0.04 sample in fact has the same IC structure as the $x=0.05$ sample. The incommensurability parameter d for x=0.04 and 0.05, where d is the distance from (1/2, 1/2) in tetragonal reciprocal lattice units, follows the linear relation d=x. These results demonstrate that the insulator to superconductor transition in the under doped regime (0.05 </= x </= 0.06) in La2-xSrxCuO4 is coincident with a transition from diagonal to collinear static stripes at low temperatures thereby evincing the intimate coupling between the one dimensional spin density modulation and the superconductivity.Comment: 9 pages 8 figure

Superconductivity from correlated hopping

We consider a chain described by a next-nearest-neighbor hopping combined with a nearest-neighbor spin flip. In two dimensions this three-body term arises from a mapping of the three-band Hubbard model for CuO$_2$ planes to a generalized $t-J$ model and for large O-O hopping favors resonance-valence-bond superconductivity of predominantly $d$-wave symmetry. Solving the ground state and low-energy excitations by analytical and numerical methods we find that the chain is a Luther-Emery liquid with correlation exponent $K_{\rho} = (2-n)^2/2$, where $n$ is the particle density.Comment: 10 pages, RevTeX 3.0 + 2 PostScript figs. Accepted for publication in Phys.Rev.

Doping and temperature dependence of incommensurate antiferromagnetism in underdoped lanthanum cuprates

The doping, temperature and energy dependence of the dynamical spin structure factors of the underdoped lanthanum cuprates in the normal state is studied within the t-J model using the fermion-spin transformation technique. Incommensurate peaks are found at $[(1\pm\delta)\pi,\pi]$, $[\pi,(1\pm\delta)\pi]$ at relatively low temperatures with $\delta$ linearly increasing with doping at the beginning and then saturating at higher dopings. These peaks broaden and weaken in amplitude with temperature and energy, in good agreement with experiments. The theory also predicts a rotation of these peaks by $\pi/4$ at even higher temperatures, being shifted to $[(1\pm \delta/\sqrt{2})\pi,(1\pm \delta/\sqrt{2})\pi]$.Comment: 11 pages, PDF file, six figures are included, accepted for publication in Physical Review

Dimerization and Incommensurate Spiral Spin Correlations in the Zigzag Spin Chain: Analogies to the Kondo Lattice

Using the density matrix renormalization group and a bosonization approach, we study a spin-1/2 antiferromagnetic Heisenberg chain with near-neighbor coupling $J_1$ and frustrating second-neighbor coupling $J_2$, particularly in the limit $J_2 >> J_1$. This system exhibits both dimerization and incommensurate spiral spin correlations. We argue that this system is closely related to a doped, spin-gapped phase of the one-dimensional Kondo lattice.Comment: 18 pages, with 13 embedded encapsulated Postscript figures, uses epsf.sty. Corrects a misstatement about the pitch angle, and contains additional reference