916 research outputs found

    Cultivating Empathy: New Perspectives on Educating Business Leaders

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    Beyond rules, procedures, and manuals lie relationships. Jettisoning a formal hierarchical company structure allows all levels of management and employees to positively interact – this is where the key driver of “empathy” is so critical to continue building these relationships and molding a common organizational purpose

    Investigating interaction-induced chaos using time-dependent density functional theory

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    Systems whose underlying classical dynamics are chaotic exhibit signatures of the chaos in their quantum mechanics. We investigate the possibility of using time-dependent density functional theory (TDDFT) to study the case when chaos is induced by electron-interaction alone. Nearest-neighbour level-spacing statistics are in principle exactly and directly accessible from TDDFT. We discuss how the TDDFT linear response procedure can reveal the mechanism of chaos induced by electron-interaction alone. A simple model of a two-electron quantum dot highlights the necessity to go beyond the adiabatic approximation in TDDFT.Comment: 8 pages, 4 figure

    The BOSS Emission-Line Lens Survey. III. : Strong Lensing of Lyα\alpha Emitters by Individual Galaxies

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    We introduce the Baryon Oscillation Spectroscopic Survey (BOSS) Emission-Line Lens Survey (BELLS) for GALaxy-Lyα\alpha EmitteR sYstems (BELLS GALLERY) Survey, which is a Hubble Space Telescope program to image a sample of galaxy-scale strong gravitational lens candidate systems with high-redshift Lyα\alpha emitters (LAEs) as the background sources. The goal of the BELLS GALLERY Survey is to illuminate dark substructures in galaxy-scale halos by exploiting the small-scale clumpiness of rest-frame far-UV emission in lensed LAEs, and to thereby constrain the slope and normalization of the substructure-mass function. In this paper, we describe in detail the spectroscopic strong-lens selection technique, which is based on methods adopted in the previous Sloan Lens ACS (SLACS) Survey, BELLS, and SLACS for the Masses Survey. We present the BELLS GALLERY sample of the 21 highest-quality galaxy--LAE candidates selected from ≈1.4×106\approx 1.4 \times 10^6 galaxy spectra in the BOSS of the Sloan Digital Sky Survey III. These systems consist of massive galaxies at redshifts of approximately 0.5 strongly lensing LAEs at redshifts from 2--3. The compact nature of LAEs makes them an ideal probe of dark substructures, with a substructure-mass sensitivity that is unprecedented in other optical strong-lens samples. The magnification effect from lensing will also reveal the structure of LAEs below 100 pc scales, providing a detailed look at the sites of the most concentrated unobscured star formation in the universe. The source code used for candidate selection is available for download as a part of this release.Comment: 14 pages, 5 figures, accepted for publication in the ApJ (ApJ, 824, 86). Minor edits to match the ApJ published versio

    Beam Studies of the Segmented Resistive WELL: a Potential Thin Sampling Element for Digital Hadron Calorimetry

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    Thick Gas Electron Multipliers (THGEMs) have the potential of constituting thin, robust sampling elements in Digital Hadron Calorimetry (DHCAL) in future colliders. We report on recent beam studies of new single- and double-THGEM-like structures; the multiplier is a Segmented Resistive WELL (SRWELL) - a single-faced THGEM in contact with a segmented resistive layer inductively coupled to readout pads. Several 10×\times10 cm2^2 configurations with a total thickness of 5-6 mm (excluding electronics) with 1 cm2^2 pads coupled to APV-SRS readout were investigated with muons and pions. Detection efficiencies in the 98% range were recorded with average pad-multiplicity of ∌\sim1.1. The resistive anode resulted in efficient discharge damping, with potential drops of a few volts; discharge probabilities were ∌10−7\sim10^{-7} for muons and ∌10−6\sim10^{-6} for pions in the double-stage configuration, at rates of a few kHz/cm2^2. Further optimization work and research on larger detectors are underway.Comment: Presented at the 13th13^{th} Vienna Conference on Instrumentation, February 2013 and submitted to its proceeding

    Generalized immune activation as a direct result of activated CD4+ T cell killing

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    Background: In addition to progressive CD4+ T cell immune deficiency, HIV infection is characterized by generalized immune activation, thought to arise from increased microbial exposure resulting from diminishing immunity. Results: Here we report that, in a virus-free mouse model, conditional ablation of activated CD4+ T cells, the targets of immunodeficiency viruses, accelerates their turnover and produces CD4+ T cell immune deficiency. More importantly, activated CD4+ T cell killing also results in generalized immune activation, which is attributable to regulatory CD4+ T cell insufficiency and preventable by regulatory CD4+ T cell reconstitution. Immune activation in this model develops independently of microbial exposure. Furthermore, microbial translocation in mice with conditional disruption of intestinal epithelial integrity affects myeloid but not T cell homeostasis. Conclusions: Although neither ablation of activated CD4+ T cells nor disruption of intestinal epithelial integrity in mice fully reproduces every aspect of HIV-associated immune dysfunction in humans, ablation of activated CD4+ T cells, but not disruption of intestinal epithelial integrity, approximates the two key immune alterations in HIV infection: CD4+ T cell immune deficiency and generalized immune activation. We therefore propose activated CD4+ T cell killing as a common etiology for both immune deficiency and activation in HIV infection

    Hydrosulfide (HS⁻) recognition and sensing in water by halogen bonding hosts

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    Hydrogen sulfide (H₂S) plays a crucial signalling role in a variety of physiological systems, existing as the hydrosulfide anion (HS⁻) at physiological pH. Combining the potency of halogen bonding (XB) for anion recognition in water with coumarin fluorophore incorporation in acyclic host structural design, the first XB receptors to bind and, more importantly, sense the hydrosulfide anion in pure water in a reversible chemosensing fashion are demonstrated. The XB receptors exhibit characteristic selective quenching of fluorescence upon binding to HS⁻. Computational DFT and molecular dynamics simulations in water corroborate the experimental anion binding observations, revealing the mode and nature of HS⁻ recognition by the XB receptors.publishe

    Novel criticality in a model with absorbing states

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    We study a one-dimensional model which undergoes a transition between an active and an absorbing phase. Monte Carlo simulations supported by some additional arguments prompted as to predict the exact location of the critical point and critical exponents in this model. The exponents ÎŽ=0.5\delta=0.5 and z=2z=2 follows from random-walk-type arguments. The exponents ÎČ=Μ⊄\beta = \nu_{\perp} are found to be non-universal and encoded in the singular part of reactivation probability, as recently discussed by H. Hinrichsen (cond-mat/0008179). A related model with quenched randomness is also studied.Comment: 5 pages, 5 figures, generalized version with the continuously changing exponent bet
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