520 research outputs found
Role of chondroitin sulfate proteoglycans (CSPGs) in synaptic plasticity and neurotransmission in mammalian spinal cord.
Chronic unilateral hemisection (HX) of the adult rat spinal cord diminishes conduction through intact fibers in the ventrolateral funiculus (VLF) contralateral to HX. Intraspinal injections of Chondroitinase-ABC, known to digest chondroitin sulfate proteoglycans (CSPGs) in the vicinity of injury, prevented this decline of axonal conduction. This was associated with improved locomotor function. We further injected three purified CSPGs into the lateral column of the uninjured cord at T10: NG2 and neurocan, which increase in the vicinity of a spinal injury, and aggrecan, which decreases. Intraspinal injection of NG2 acutely depressed axonal conduction through the injection region in a dose dependent manner. Similar injections of saline, aggrecan, or neurocan had no significant effect. These results identify a novel acute action of CSPGs on axonal conduction in spinal cord, and suggest that antagonism of proteoglycans reverses or prevents the decline of axonal conduction, in addition to stimulating axonal growth
An Investigation Of The Comparative Accuracy And Bias Of Equity Securities Analysts East And West European Firms Earnings Forecasts
This research investigates the comparative accuracy and bias of West European and East European firms equity securities analysts earnings forecasts for 29 European countries 12 of which are characterized as being East European. We utilize measures of equity securities analysts earnings forecast accuracy and bias in making comparisons of the statistical properties of earnings forecasts for firms having domiciles in East European and West European countries. Our results indicate that securities analysts earnings forecasts for companies domiciled with East European countries display larger forecast error and greater degree of optimistic forecast bias. Our results persist after controlling for cross-listing of ADRs on US securities exchanges. We generalize our results using the growing literature on the ever-changing characteristics of the Russian people, Russian business professionals and the rapidly evolving Russian stock market and the transitional Russian political economy
Particle deposition in a realistic geometry of the human conducting airways: Effects of inlet velocity profile, inhalation flowrate and electrostatic charge:Effects of inlet velocity profile, inhalation flowrate and electrostatic charge
AbstractUnderstanding the multitude of factors that control pulmonary deposition is important in assessing the therapeutic or toxic effects of inhaled particles. The use of increasingly sophisticated in silico models has improved our overall understanding, but model realism remains elusive. In this work, we use Large Eddy Simulations (LES) to investigate the deposition of inhaled aerosol particles with diameters of dp=0.1,0.5,1,2.5,5 and 10μm (particle density of 1200kg/m3). We use a reconstructed geometry of the human airways obtained via computed tomography and assess the effects of inlet flow conditions, particle size, electrostatic charge, and flowrate. While most computer simulations assume a uniform velocity at the mouth inlet, we found that using a more realistic inlet profile based on Laser Doppler Anemometry measurements resulted in enhanced deposition, mostly on the tongue. Nevertheless, flow field differences due to the inlet conditions are largely smoothed out just a short distance downstream of the mouth inlet as a result of the complex geometry. Increasing the inhalation flowrate from sedentary to activity conditions left the mean flowfield structures largely unaffected. Nevertheless, at the higher flowrates turbulent intensities persisted further downstream in the main bronchi. For dp>2.5μm, the overall Deposition Fractions (DF) increased with flowrate due to greater inertial impaction in the oropharynx. Below dp=1.0μm, the DF was largely independent of particle size; it also increased with flowrate, but remained significantly lower. Electrostatic charge increased the overall DF of smaller particles by as much as sevenfold, with most of the increase located in the mouth–throat. Moreover, significant enhancement in deposition was found in the left and right lung sub-regions of our reconstructed geometry. Although there was a relatively small impact of inhalation flowrate on the deposition of charged particles for sizes dp<2.5μm, impaction prevailed over electrostatic deposition for larger particles as the flowrate was increased. Overall, we report a significant interplay between particle size, electrostatic charge, and flowrate. Our results suggest that in silico models should be customized for specific applications, ensuring all relevant physical effects are accounted for in a self-consistent fashion
HST Measurements of the Expansion of NGC 6543: Parallax Distance and Nebular Evolution
The optical expansion parallax of NGC 6543 has been detected and measured
using two epochs of HST images separated by a time baseline of only three
years. We have utilized three separate methods of deriving the angular
expansion of bright fiducials, the results of which are in excellent agreement.
We combine our angular expansion estimates with spectroscopically obtained
expansion velocities to derive a distance to NGC 6543 of 1001269 pc. The
deduced kinematic age of the inner bright core of the nebula is 1039259
years; however, the kinematic age of the polar caps that surround the core is
larger - perhaps the result of deceleration or earlier mass ejection. The
morphology and expansion patterns of NGC 6543 provide insight into a complex
history of axisymmetric, interacting stellar mass ejections.Comment: Accepted for publication in AJ. 18 pages. 6 figure
Direct observation of Levy flight of holes in bulk n-InP
We study the photoluminescence spectra excited at an edge side of n-InP slabs
and observed from the broadside. In a moderately doped sample the intensity
drops off as a power-law function of the distance from the excitation - up to
several millimeters - with no change in the spectral shape.The hole
distribution is described by a stationary Levy-flight process over more than
two orders of magnitude in both the distance and hole concentration. For
heavily-doped samples, the power law is truncated by free-carrier absorption.
Our experiments are near-perfectly described by the Biberman-Holstein transport
equation with parameters found from independent optical experiments.Comment: 4 pages, 3 figure
Stellar Astrophysics with a Dispersed Fourier Transform Spectrograph. II. Orbits of Double-lined Spectroscopic Binaries
We present orbital parameters for six double-lined spectroscopic binaries
(iota Pegasi, omega Draconis, 12 Bootis, V1143 Cygni, beta Aurigae, and Mizar
A) and two double-lined triple star systems (kappa Pegasi and eta Virginis).
The orbital fits are based upon high-precision radial velocity observations
made with a dispersed Fourier Transform Spectrograph, or dFTS, a new instrument
which combines interferometric and dispersive elements. For some of the
double-lined binaries with known inclination angles, the quality of our RV data
permits us to determine the masses M_1 and M_2 of the stellar components with
relative errors as small as 0.2%.Comment: 41 pages, 8 figures, accepted by A
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