3,908 research outputs found

    TGA/FTIR Studies on the Thermal Degradation of some Polymeric Sulfonic and Phosphonic Acids and Their Sodium Salts

    Get PDF
    The thermal degradation of poly(vinyl sulfonic acid) and its sodium salt, poly(4-styrenesulfonic acid) and its sodium salt, and poly(vinylphosphonic acid) was studied by a combination of techniques, including TGA/FTIR, to identify the volatile products which were evolved during the degradation as well as analysis of the residues which were obtained in order to propose a mechanism for the degradation. The motivation for the work was to attempt to identify new monomers which could be graft copolymerized onto a polymer in order to improve the thermal stability of that polymer

    Adiabatic Quantum Search in Open Systems

    Get PDF
    Adiabatic quantum algorithms represent a promising approach to universal quantum computation. Whilst in a closed system these algorithms are limited by avoided level crossings, where the gap becomes exponentially small in the system size, their robustness in open systems remains unresolved. We study the dynamics in the proximity of such an avoided level crossing associated with the adiabatic quantum search algorithm in a quantum system that is coupled to a generic environment. At zero temperature, we find that the algorithm remains scalable provided the noise spectral density of the environment decays sufficiently fast at low frequencies. At finite temperature, however, scattering processes render the algorithm inefficient and no quantum speedup can be achieved. Owing to the generic nature of our model, we expect our results to be widely applicable to other adiabatic quantum algorithms.Comment: Accepted version. 6 pages, 2 figures, 10 pages supplemental material

    The Class 0 Protostar BHR71: Herschel Observations and Dust Continuum Models

    Full text link
    We use Herschel spectrophotometry of BHR71, an embedded Class 0 protostar, to provide new constraints on its physical properties. We detect 645 (non-unique) spectral lines amongst all spatial pixels. At least 61 different spectral lines originate from the central region. A CO rotational diagram analysis shows four excitation temperature components, 43 K, 197 K, 397 K, and 1057 K. Low-J CO lines trace the outflow while the high-J CO lines are centered on the infrared source. The low-excitation emission lines of H2O trace the large-scale outflow, while the high-excitation emission lines trace a small-scale distribution around the equatorial plane. We model the envelope structure using the dust radiative transfer code, Hyperion, incorporating rotational collapse, an outer static envelope, outflow cavity, and disk. The evolution of a rotating collapsing envelope can be constrained by the far-infrared/millimeter SED along with the azimuthally-averaged radial intensity profile, and the structure of the outflow cavity plays a critical role at shorter wavelengths. Emission at 20-40 um requires a cavity with a constant-density inner region and a power-law density outer region. The best fit model has an envelope mass of 19 solar mass inside a radius of 0.315 pc and a central luminosity of 18.8 solar luminosity. The time since collapse began is 24630-44000 yr, most likely around 36000 yr. The corresponding mass infall rate in the envelope (1.2x10−5^{-5} solar mass per year) is comparable to the stellar mass accretion rate, while the mass loss rate estimated from the CO outflow is 20% of the stellar mass accretion rate. We find no evidence for episodic accretion.Comment: Accepted for publication in ApJ. 33 pages; 34 figures; 4 table

    Co-Evolutionary Learning for Cognitive Computer Generated Entities

    Get PDF
    In this paper, an approach is advocated to use a hybrid approach towards learning behaviour for computer generated entities (CGEs) in a serious gaming setting. Hereby, an agent equipped with cognitive model is used but this agent is enhanced with Machine Learning (ML) capabilities. This facilitates the agent to exhibit human like behaviour but avoid an expert having to define all parameters explicitly. More in particular, the ML approach utilizes co-evolution as a learning paradigm. An evaluation in the domain of one-versus-one air combat shows promising results

    Trends in Drug Utilization, Glycemic Control, and Rates of Severe Hypoglycemia, 2006-2013.

    Get PDF
    ObjectiveTo examine temporal trends in utilization of glucose-lowering medications, glycemic control, and rate of severe hypoglycemia among patients with type 2 diabetes (T2DM).Research design and methodsUsing claims data from 1.66 million privately insured and Medicare Advantage patients with T2DM from 2006 to 2013, we estimated the annual 1) age- and sex-standardized proportion of patients who filled each class of agents; 2) age-, sex-, race-, and region-standardized proportion with hemoglobin A1c (HbA1c) <6%, 6 to <7%, 7 to <8%, 8 to <9%, ≥9%; and 3) age- and sex-standardized rate of severe hypoglycemia among those using medications. Proportions were calculated overall and stratified by age-group (18-44, 45-64, 65-74, and ≥75 years) and number of chronic comorbidities (zero, one, and two or more).ResultsFrom 2006 to 2013, use increased for metformin (from 47.6 to 53.5%), dipeptidyl peptidase 4 inhibitors (0.5 to 14.9%), and insulin (17.1 to 23.0%) but declined for sulfonylureas (38.8 to 30.8%) and thiazolidinediones (28.5 to 5.6%; all P < 0.001). The proportion of patients with HbA1c <7% declined (from 56.4 to 54.2%; P < 0.001) and with HbA1c ≥9% increased (9.9 to 12.2%; P < 0.001). Glycemic control varied by age and was poor among 23.3% of the youngest and 6.3% of the oldest patients in 2013. The overall rate of severe hypoglycemia remained the same (1.3 per 100 person-years; P = 0.72), declined modestly among the oldest patients (from 2.9 to 2.3; P < 0.001), and remained high among those with two or more comorbidities (3.2 to 3.5; P = 0.36).ConclusionsDuring the recent 8-year period, the use of glucose-lowering drugs has changed dramatically among patients with T2DM. Overall glycemic control has not improved and remains poor among nearly a quarter of the youngest patients. The overall rate of severe hypoglycemia remains largely unchanged

    Association Between Rare TP53 variants and Cancer Predisposition in Colorecta, Melanoma, Ovarian, Pancreatic, and Prostate Cancer

    Get PDF
    https://openworks.mdanderson.org/sumexp22/1060/thumbnail.jp

    Diagnosing 0.1–10 au Scale Morphology of the FU Ori Disk Using ALMA and VLTI/GRAVITY

    Get PDF
    We report new Atacama Large Millimeter/submillimeter Array Band 3 (86–100 GHz; ~80 mas angular resolution) and Band 4 (146–160 GHz; ~50 mas angular resolution) observations of the dust continuum emission toward the archetypal and ongoing accretion burst young stellar object FU Ori, which simultaneously covered its companion, FU Ori S. In addition, we present near-infrared (2–2.45 μm) observations of FU Ori taken with the General Relativity Analysis via VLT InTerferometrY (GRAVITY; ~1 mas angular resolution) instrument on the Very Large Telescope Interferometer (VLTI). We find that the emission in both FU Ori and FU Ori S at (sub)millimeter and near-infrared bands is dominated by structures inward of ~10 au radii. We detected closure phases close to zero from FU Ori with VLTI/GRAVITY, which indicate the source is approximately centrally symmetric and therefore is likely viewed nearly face-on. Our simple model to fit the GRAVITY data shows that the inner 0.4 au radii of the FU Ori disk has a triangular spectral shape at 2–2.45 μm, which is consistent with the H2O and CO absorption features in a 10−4 M ⊙ yr−1, viscously heated accretion disk. At larger (~0.4–10 au) radii, our analysis shows that viscous heating may also explain the observed (sub)millimeter and centimeter spectral energy distribution when we assume a constant, ~10−4 M ⊙ yr−1 mass inflow rate in this region. This explains how the inner 0.4 au disk is replenished with mass at a modest rate, such that it neither depletes nor accumulates significant masses over its short dynamic timescale. Finally, we tentatively detect evidence of vertical dust settling in the inner 10 au of the FU Ori disk, but confirmation requires more complete spectral sampling in the centimeter bands
    • …
    corecore