Sliding Luttinger liquid phases

We study systems of coupled spin-gapped and gapless Luttinger liquids. First, we establish the existence of a sliding Luttinger liquid phase for a system of weakly coupled parallel quantum wires, with and without disorder. It is shown that the coupling can {\it stabilize} a Luttinger liquid phase in the presence of disorder. We then extend our analysis to a system of crossed Luttinger liquids and establish the stability of a non-Fermi liquid state: the crossed sliding Luttinger liquid phase (CSLL). In this phase the system exhibits a finite-temperature, long-wavelength, isotropic electric conductivity that diverges as a power law in temperature $T$ as $T \to 0$. This two-dimensional system has many properties of a true isotropic Luttinger liquid, though at zero temperature it becomes anisotropic. An extension of this model to a three-dimensional stack exhibits a much higher in-plane conductivity than the conductivity in a perpendicular direction.Comment: Revtex, 18 pages, 8 figure

Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19

IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19. Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19. DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 non–critically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022). INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (n = 257), ARB (n = 248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; n = 10), or no RAS inhibitor (control; n = 264) for up to 10 days. MAIN OUTCOMES AND MEASURES The primary outcome was organ support–free days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes. RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ support–free days among critically ill patients was 10 (–1 to 16) in the ACE inhibitor group (n = 231), 8 (–1 to 17) in the ARB group (n = 217), and 12 (0 to 17) in the control group (n = 231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ support–free days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively). CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570

One-dimensional quantum walks

We define and analyze quantum computational variants of random walks on one-dimensional lattices. In particular, we analyze a quantum analog of the symmetric random walk, which we call the Hadamard walk. Several striking differences between the quantum and classical cases are ob- served. For example, when unrestricted in either direction, the Hadamard walk has position that is nearly uniformly distributed in the range [-t/√2, t/√2] after t steps, which is in sharp contrast to the classical random walk, which has distance O(√t) from the origin with high probability. With an absorbing boundary immediately to the left of the starting position, the probability that the walk exits to the left is 2/π, and with an additional absorbing boundary at location n, the probability that the walk exits to the left actually increases, approaching 1/√2 in the limit. In the classical case both values are 1

The dimensions of the corpus callosum of the cerebrum

AimsTo determine the dimensions of the human corpus callosum and its parts. The objective was also to know its location in the cerebral hemisphere of South Indians. Methods Twenty mid-sagittal sections from formalin fixed human cadaveric brain specimens were used for this study and the parameters recorded were: distances from frontal pole to occipital pole (AB), inferior surface to the superior surface of the brain (CD), frontal pole of brain to genu (AG), occipital pole of cerebrum to corpus callosum splenium (BS), from splenium of corpus callosum to superior colliculus (Ls-SC) and inferior colliculus (Ls-IC), genu to fornix (GF), outer curvature O (G-S) and inner curvature I (G-S) from genu to splenium, the entire outer curvature (OUTCR) and inner curvature (INCUR) from beginning of corpus callosum rostrum to the splenium end. We did also measure the thicknesses of its splenium (S), isthmus (I), body (T), genu (G) and rostrum (R). ResultsStatistical analysis using correlation study showed significance between A-B and B-S, O (G-S) and INCUR, O (G-S) and OUTCR, A-G and R, T and I. Highly significant correlations were found between C-D and Ls-IC, O (G-S) and I (G-S), I (G-S) and G-F, G-F, and G. Very highly significant correlations were seen between I (G-S) and INCUR, Ls-SC, and Ls-IC, T and S. ConclusionThis morphometric study on the corpus callosum provides data that could be valuable in the diagnosis of lesions of the corpus callosum. The data are of particular relevance to neurologists and radiologists