13,877 research outputs found

    An analysis of defibrillation and cardiac resynchronization therapy strategies in patients with failing systemic right ventricles

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    Includes bibliographical references (leaves 52-56).The expanding application of cardiac resynchronization (CRT) and implantable cardioverter-defibrillator therapy (lCD) to include patients with congenital heart disease requires careful evaluation of selection criteria and unconventional adaptive strategies to ensure clinical efficacy. A single centre prospective analysis of adults post atrial redirection surgery (Mustard operation) for dextro-transposition of the great arteries (d-TGA) presenting with systemic right ventricular (sRV) dysfunction and at risk of sudden cardiac death (SCD). All patients ( mean age 25 years, range 18-35) with varying functional disability{New York Heart Association (NYHA) II-III} receiving ICDs ± concomitant CRT were evaluated. Total follow-up period was 24 months. A patient individualized approach was used for device implantation. Endocardial, epicardial and transthoracic defibrillation strategies were examined in 5 consecutive cases. A hybridized form of CRT was employed in two patients. Only one patient demonstrated response to therapy while the other deteriorated during biventricular pacing (BVP). This prompted a novel approach to CRT using noncontact mapping (NCM) and acute intra-arterial blood pressure response to guide endocardialsRV lead placement in a single patient. The ejection fraction increased from 23 -33% within 1week post procedure and clinical improvement was sustained after 6-months follow-up. Application of CRT II CD therapy to patients with sRV dysfunction requires individualized and adaptive strategies to overcome anatomical constraints. This study represents a chronological and evolutionary account of these measures

    The Rarity of Star Formation in Brightest Cluster Galaxies as Measured by WISE

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    We present the mid-infrared (IR) star formation rates of 245 X-ray selected, nearby (z<0.1) brightest cluster galaxies (BCGs). A homogeneous and volume limited sample of BCGs was created by X-ray selecting clusters with L_x > 1x10^44 erg/s. The Wide-Field Infrared Survey Explorer (WISE) AllWISE Data Release provides the first measurement of the 12 micron star formation indicator for all BCGs in the nearby Universe. Perseus A and Cygnus A are the only galaxies in our sample to have star formation rates of > 40 M_sol/yr, indicating that these two galaxies are highly unusual at current times. Stellar populations of 99 +/- 0.6 % of local BCGs are (approximately) passively evolving, with star formation rates of <10 M_sol/yr. We find that in general, star formation produces only modest BCG growth at the current epoch.Comment: 5 pages, 3 figures, accepted for publication in MNRA

    Bosonic molecules in a lattice: unusual fluid phase from multichannel interactions

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    We show that multichannel interactions significantly alter the phase diagram of ultracold bosonic molecules in an optical lattice. Most prominently, an unusual fluid region intervenes between the conventional superfluid and the Mott insulator. In it, number fluctuations remain but phase coherence is suppressed by a significant factor. This factor can be made arbitrarily large, at least in a two-site configuration. We calculate the phase diagram using complementary methods, including Gutzwiller mean-field and density matrix renormalization group (DMRG) calculations. Although we focus on bosonic molecules without dipolar interactions, we expect multichannel interactions to remain important for dipolar interacting and fermionic molecules.Comment: 6 pages incl. refs, 4 figure

    Raiders of the Lost Architecture: Kernels for Bayesian Optimization in Conditional Parameter Spaces

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    In practical Bayesian optimization, we must often search over structures with differing numbers of parameters. For instance, we may wish to search over neural network architectures with an unknown number of layers. To relate performance data gathered for different architectures, we define a new kernel for conditional parameter spaces that explicitly includes information about which parameters are relevant in a given structure. We show that this kernel improves model quality and Bayesian optimization results over several simpler baseline kernels.Comment: 6 pages, 3 figures. Appeared in the NIPS 2013 workshop on Bayesian optimizatio

    The many assembly histories of massive void galaxies as revealed by integral field spectroscopy

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    We present the first detailed integral field spectroscopy study of nine central void galaxies with M*>10¹⁰Mʘ using the Wide Field Spectrograph to determine how a range of assembly histories manifest themselves in the current day Universe.While the majority of these galaxies are evolving secularly, we find a range of morphologies, merger histories and stellar population distributions, though similarly low Hα-derived star formation rates (10¹⁰Mʘ have similarly low star formation rates

    Effects of Δ⁹-tetrahydrocannabinol (THC) vapor inhalation in Sprague-Dawley and Wistar rats.

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    An inhalation system based on e-cigarette technology produces hypothermic and antinociceptive effects of Δ⁹-tetrahydrocannabinol (THC) in rats. Indirect comparison of some prior investigations suggested differential impact of inhaled THC between Wistar (WI) and Sprague-Dawley (SD) rats; thus, this study was conducted to directly compare the strains across inhaled and injected routes of administration. Groups (N = 8 per strain) of age-matched male SD and WI rats were prepared with radiotelemetry devices to measure temperature and then exposed to vapor from the propylene glycol (PG) vehicle or THC (25-200 mg/mL of PG) for 30 or 40 min. Additional studies evaluated effects of THC inhalation on plasma THC (50-200 mg/mL) and nociception (100-200 mg/mL) as well as the thermoregulatory effect of intraperitoneal injection of THC (5-30 mg/kg). Hypothermic effects of THC were more pronounced in SD rats, where plasma levels of THC were identical across strains, under either fixed inhalation conditions or injection of a mg/kg equivalent dose. Strain differences in hypothermia were largest after i.p. injection of THC, with SD rats exhibiting dose-dependent temperature reduction after 5 or 10 mg/kg, i.p. and the WI rats only exhibiting significant hypothermia after 20 mg/kg, i.p. The antinociceptive effects of inhaled THC (100, 200 mg/mL) did not differ significantly across the strains. These studies confirm an insensitivity of WI rats, compared with SD rats, to hypothermia induced by THC following inhalation conditions that produced identical plasma THC and antinociception. Thus, quantitative, albeit not qualitative, strain differences may be obtained when studying thermoregulatory effects of THC. (PsycInfo Database Record (c) 2021 APA, all rights reserved)

    The asymptotic equivalence of fixed heat flux and fixed temperature thermal boundary conditions for rapidly rotating convection

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    The influence of fixed temperature and fixed heat flux thermal boundary conditions on rapidly rotating convection in the plane layer geometry is investigated for the case of stress-free mechanical boundary conditions. It is shown that whereas the leading order system satisfies fixed temperature boundary conditions implicitly, a double boundary layer structure is necessary to satisfy the fixed heat flux thermal boundary conditions. The boundary layers consist of a classical Ekman layer adjacent to the solid boundaries that adjust viscous stresses to zero, and a layer in thermal wind balance just outside the Ekman layers adjusts the temperature such that the fixed heat flux thermal boundary conditions are satisfied. The influence of these boundary layers on the interior geostrophically balanced convection is shown to be asymptotically weak, however. Upon defining a simple rescaling of the thermal variables, the leading order reduced system of governing equations are therefore equivalent for both boundary conditions. These results imply that any horizontal thermal variation along the boundaries that varies on the scale of the convection has no leading order influence on the interior convection
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