1,051 research outputs found
Quantum logic as superbraids of entangled qubit world lines
Presented is a topological representation of quantum logic that views
entangled qubit spacetime histories (or qubit world lines) as a generalized
braid, referred to as a superbraid. The crossing of world lines is purely
quantum in nature, most conveniently expressed analytically with
ladder-operator-based quantum gates. At a crossing, independent world lines can
become entangled. Complicated superbraids are systematically reduced by
recursively applying novel quantum skein relations. If the superbraid is closed
(e.g. representing quantum circuits with closed-loop feedback, quantum lattice
gas algorithms, loop or vacuum diagrams in quantum field theory), then one can
decompose the resulting superlink into an entangled superposition of classical
links. In turn, for each member link, one can compute a link invariant, e.g.
the Jones polynomial. Thus, a superlink possesses a unique link invariant
expressed as an entangled superposition of classical link invariants.Comment: 4 page
Limiting the Duration of Medication Assisted Treatment for Opioid Addiction: Will New State Policies Help or Hurt?
This presentation details the impact of state Medicaid programs placing lifetime limits on buprenorphine therapy for individuals with opioid dependence. The research reveals that setting limits does not save money or help the patient
Leptonic and Semileptonic Decays of Charm and Bottom Hadrons
We review the experimental measurements and theoretical descriptions of
leptonic and semileptonic decays of particles containing a single heavy quark,
either charm or bottom. Measurements of bottom semileptonic decays are used to
determine the magnitudes of two fundamental parameters of the standard model,
the Cabibbo-Kobayashi-Maskawa matrix elements and . These
parameters are connected with the physics of quark flavor and mass, and they
have important implications for the breakdown of CP symmetry. To extract
precise values of and from measurements, however,
requires a good understanding of the decay dynamics. Measurements of both charm
and bottom decay distributions provide information on the interactions
governing these processes. The underlying weak transition in each case is
relatively simple, but the strong interactions that bind the quarks into
hadrons introduce complications. We also discuss new theoretical approaches,
especially heavy-quark effective theory and lattice QCD, which are providing
insights and predictions now being tested by experiment. An international
effort at many laboratories will rapidly advance knowledge of this physics
during the next decade.Comment: This review article will be published in Reviews of Modern Physics in
the fall, 1995. This file contains only the abstract and the table of
contents. The full 168-page document including 47 figures is available at
http://charm.physics.ucsb.edu/papers/slrevtex.p
Chronic Losartan Administration Reduces Mortality and Preserves Cardiac but Not Skeletal Muscle Function in Dystrophic Mice
Duchenne muscular dystrophy (DMD) is a degenerative disorder affecting skeletal and cardiac muscle for which there is no effective therapy. Angiotension receptor blockade (ARB) has excellent therapeutic potential in DMD based on recent data demonstrating attenuation of skeletal muscle disease progression during 6–9 months of therapy in the mdx mouse model of DMD. Since cardiac-related death is major cause of mortality in DMD, it is important to evaluate the effect of any novel treatment on the heart. Therefore, we evaluated the long-term impact of ARB on both the skeletal muscle and cardiac phenotype of the mdx mouse. Mdx mice received either losartan (0.6 g/L) (n = 8) or standard drinking water (n = 9) for two years, after which echocardiography was performed to assess cardiac function. Skeletal muscle weight, morphology, and function were assessed. Fibrosis was evaluated in the diaphragm and heart by Trichrome stain and by determination of tissue hydroxyproline content. By the study endpoint, 88% of treated mice were alive compared to only 44% of untreated (p = 0.05). No difference in skeletal muscle morphology, function, or fibrosis was noted in losartan-treated animals. Cardiac function was significantly preserved with losartan treatment, with a trend towards reduction in cardiac fibrosis. We saw no impact on the skeletal muscle disease progression, suggesting that other pathways that trigger fibrosis dominate over angiotensin II in skeletal muscle long term, unlike the situation in the heart. Our study suggests that ARB may be an important prophylactic treatment for DMD-associated cardiomyopathy, but will not impact skeletal muscle disease
Interhospital Transfer Before Thrombectomy Is Associated With Delayed Treatment and Worse Outcome in the STRATIS Registry (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke).
BACKGROUND: Endovascular treatment with mechanical thrombectomy (MT) is beneficial for patients with acute stroke suffering a large-vessel occlusion, although treatment efficacy is highly time-dependent. We hypothesized that interhospital transfer to endovascular-capable centers would result in treatment delays and worse clinical outcomes compared with direct presentation.
METHODS: STRATIS (Systematic Evaluation of Patients Treated With Neurothrombectomy Devices for Acute Ischemic Stroke) was a prospective, multicenter, observational, single-arm study of real-world MT for acute stroke because of anterior-circulation large-vessel occlusion performed at 55 sites over 2 years, including 1000 patients with severe stroke and treated within 8 hours. Patients underwent MT with or without intravenous tissue plasminogen activator and were admitted to endovascular-capable centers via either interhospital transfer or direct presentation. The primary clinical outcome was functional independence (modified Rankin Score 0-2) at 90 days. We assessed (1) real-world time metrics of stroke care delivery, (2) outcome differences between direct and transfer patients undergoing MT, and (3) the potential impact of local hospital bypass.
RESULTS: A total of 984 patients were analyzed. Median onset-to-revascularization time was 202.0 minutes for direct versus 311.5 minutes for transfer patients (
CONCLUSIONS: In this large, real-world study, interhospital transfer was associated with significant treatment delays and lower chance of good outcome. Strategies to facilitate more rapid identification of large-vessel occlusion and direct routing to endovascular-capable centers for patients with severe stroke may improve outcomes.
CLINICAL TRIAL REGISTRATION: URL: https://www.clinicaltrials.gov. Unique identifier: NCT02239640
Enhancing studies of the connectome in autism using the autism brain imaging data exchange II
The second iteration of the Autism Brain Imaging Data Exchange (ABIDE II) aims to enhance the scope of brain connectomics research in Autism Spectrum Disorder (ASD). Consistent with the initial ABIDE effort (ABIDE I), that released 1112 datasets in 2012, this new multisite open-data resource is an aggregate of resting state functional magnetic resonance imaging (MRI) and corresponding structural MRI and phenotypic datasets. ABIDE II includes datasets from an additional 487 individuals with ASD and 557 controls previously collected across 16 international institutions. The combination of ABIDE I and ABIDE II provides investigators with 2156 unique cross-sectional datasets allowing selection of samples for discovery and/or replication. This sample size can also facilitate the identification of neurobiological subgroups, as well as preliminary examinations of sex differences in ASD. Additionally, ABIDE II includes a range of psychiatric variables to inform our understanding of the neural correlates of co-occurring psychopathology; 284 diffusion imaging datasets are also included. It is anticipated that these enhancements will contribute to unraveling key sources of ASD heterogeneity
Designing Digital Engagements:Approaches to creative practice and adaptable programming for archaeological visualisation
The Relationship between Phytoplankton Distribution and Water Column Characteristics in North West European Shelf Sea Waters
Phytoplankton underpin the marine food web in shelf seas, with some species having properties that are harmful to human health and coastal aquaculture. Pressures such as climate change and anthropogenic nutrient input are hypothesized to influence phytoplankton community composition and distribution. Yet the primary environmental drivers in shelf seas are poorly understood. To begin to address this in North Western European waters, the phytoplankton community composition was assessed in light of measured physical and chemical drivers during the “Ellett Line” cruise of autumn 2001 across the Scottish Continental shelf and into adjacent open Atlantic waters. Spatial variability existed in both phytoplankton and environmental conditions, with clear differences not only between on and off shelf stations but also between different on shelf locations. Temperature/salinity plots demonstrated different water masses existed in the region. In turn, principal component analysis (PCA), of the measured environmental conditions (temperature, salinity, water density and inorganic nutrient concentrations) clearly discriminated between shelf and oceanic stations on the basis of DIN∶DSi ratio that was correlated with both salinity and temperature. Discrimination between shelf stations was also related to this ratio, but also the concentration of DIN and DSi. The phytoplankton community was diatom dominated, with multidimensional scaling (MDS) demonstrating spatial variability in its composition. Redundancy analysis (RDA) was used to investigate the link between environment and the phytoplankton community. This demonstrated a significant relationship between community composition and water mass as indexed by salinity (whole community), and both salinity and DIN∶DSi (diatoms alone). Diatoms of the Pseudo-nitzschia seriata group occurred at densities potentially harmful to shellfish aquaculture, with the potential for toxicity being elevated by the likelihood of DSi limitation of growth at most stations and depths
Dark Energy Survey Year 3 results: Constraints on extensions to ΛcDM with weak lensing and galaxy clustering
We constrain six possible extensions to the Λ cold dark matter (CDM) model using measurements from the Dark Energy Survey's first three years of observations, alone and in combination with external cosmological probes. The DES data are the two-point correlation functions of weak gravitational lensing, galaxy clustering, and their cross-correlation. We use simulated data vectors and blind analyses of real data to validate the robustness of our results to astrophysical and modeling systematic errors. In many cases, constraining power is limited by the absence of theoretical predictions beyond the linear regime that are reliable at our required precision. The ΛCDM extensions are dark energy with a time-dependent equation of state, nonzero spatial curvature, additional relativistic degrees of freedom, sterile neutrinos with eV-scale mass, modifications of gravitational physics, and a binned σ8(z) model which serves as a phenomenological probe of structure growth. For the time-varying dark energy equation of state evaluated at the pivot redshift we find (wp,wa)=(-0.99-0.17+0.28,-0.9±1.2) at 68% confidence with zp=0.24 from the DES measurements alone, and (wp,wa)=(-1.03-0.03+0.04,-0.4-0.3+0.4) with zp=0.21 for the combination of all data considered. Curvature constraints of ωk=0.0009±0.0017 and effective relativistic species Neff=3.10-0.16+0.15 are dominated by external data, though adding DES information to external low-redshift probes tightens the ωk constraints that can be made without cosmic microwave background observables by 20%. For massive sterile neutrinos, DES combined with external data improves the upper bound on the mass meff by a factor of 3 compared to previous analyses, giving 95% limits of (ΔNeff,meff)≤(0.28,0.20 eV) when using priors matching a comparable Planck analysis. For modified gravity, we constrain changes to the lensing and Poisson equations controlled by functions ς(k,z)=ς0ωΛ(z)/ωΛ,0 and μ(k,z)=μ0ωΛ(z)/ωΛ,0, respectively, to ς0=0.6-0.5+0.4 from DES alone and (ς0,μ0)=(0.04±0.05,0.08-0.19+0.21) for the combination of all data, both at 68% confidence. Overall, we find no significant evidence for physics beyond ΛCDM
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