9,304 research outputs found
A corrosion control manual for rail rapid transit
In 1979, during the planning stage of the Metropolitan Dade County Transit System, the need was expressed for a corrosion control manual oriented to urban rapid transit system use. This manual responds to that need. The objective of the manual is to aid rail rapid transit agencies by providing practical solutions to selected corrosion problems. The scope of the manual encompasses corrosion problems of the facilities of rapid transit systems: structures and tracks, platforms and stations, power and signals, and cars. It also discusses stray electric current corrosion. Both design and maintenance solutions are provided for each problem. Also included are descriptions of the types of corrosion and their causes, descriptions of rapid transit properties, a list of corrosion control committees and NASA, DOD, and ASTM specifications and design criteria to which reference is made in the manual. A bibliography of papers and excerpts of reports and a glossary of frequency used terms are provided
A COMPARISON OF THE NATIONAL FOOTBALL LEAGUE COACHES STRENGTH AND CONDITIONING PRACTICES 1997-1998 TO 2018
This study describes the results of a survey of the strength and conditioning practices of the National Football League’s strength and conditioning coaches. The survey response rate was 28.1% (9 of 32 NFL teams) agreeing to participate. Subjects test 6.83 ± 3.06 fitness variables using 9.00 ± 3.74 tests; compared to 7.0 fitness variables using 10.0 tests in ‘97-98. Subjects prescribe resistance training 2.33 ± .81 days per week when in-season; compared to 2.8 ± 0.8 days per week in ’97-98. The average in-season training session duration was 37.50 ± 12.54 mins; compared to 48.5 ±13.2 mins in ’97-98. Findings indicate that there were statistically significant results for NFL coaching tenure (p= .005) and off-season resistance training frequency (p= .007). This study serves as a review as well as a source of applied information regarding training program design
Does Antiretroviral Treatment Reduce Case Fatality Among HIV-Positive Patients with Tuberculosis in Malawi?
SETTING: Thyolo district, Malawi. OBJECTIVES: To report on 1) case fatality among human immunodeficiency virus (HIV) positive tuberculosis (TB) patients while on anti-tuberculosis treatment and 2) whether antiretroviral treatment (ART) initiated during the continuation phase of TB treatment reduces case fatality. DESIGN: Retrospective cohort analysis. METHODS: Comparative analysis of treatment outcomes for TB patients registered between January and December 2004. RESULTS: Of 983 newly registered TB patients receiving diagnostic HIV testing, 658 (67%) were HIV-positive. A total of 132 (20%) patients died during the 8-month course of anti-tuberculosis treatment, of whom 82 (62%) died within the first 2 months of treatment when ART was not provided (cumulative incidence 3.0, 95%CI 2.5-3.6 per 100 person-years). A total of 576 TB patients started the continuation phase of anti-tuberculosis treatment, 180 (31%) of whom were started on ART. The case-fatality rate per 100 person-years was not significantly different for patients on ART (1.0, 95%CI 0.6-1.7) and those without ART (1.2, 95%CI 0.9-1.7, adjusted hazard ratio 0.86, 95%CI 0.4-1.6, P = 0.6) CONCLUSIONS: ART provided in the continuation phase of TB treatment does not have a significant impact on reducing case fatality. Reasons for this and possible measures to reduce high case fatality in the initial phase of TB treatment are discussed
Correction to “Mercury and monomethylmercury in fluids from Sea Cliff submarine hydrothermal field, Gorda Ridge”
Author Posting. © American Geophysical Union, 2007. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geophysical Research Letters 34 (2007): L02603, doi:10.1029/2006GL028747
Insights into the room temperature magnetism of ZnO/Co3O4 mixtures
The origin of room temperature (RT) ferromagneticlike behavior in ZnO-based
diluted magnetic semiconductors is still an unclear topic. The present work
concentrates on the appearance of RT magnetic moments in just mixed ZnO/Co3O4
mixtures without thermal treatment. In this study, it is shown that the
magnetism seems to be related to surface reduction of the Co3O4 nanoparticles,
in which, an antiferromagnetic Co3O4 nanoparticle (core) is surrounded by a
CoO-like shell. This singular superficial magnetism has also been found in
other mixtures with semiconductors such as TiO2 and insulators such as Al2O3
Edwards thermodynamics of the jamming transition for frictionless packings: ergodicity test and role of angoricity and compactivity
This paper illustrates how the tools of equilibrium statistical mechanics can
help to explain a far-from-equilibrium problem: the jamming transition in
frictionless granular materials. Edwards ideas consist of proposing a
statistical ensemble of volume and stress fluctuations through the
thermodynamic notion of entropy, compactivity, X, and angoricity, A (two
temperature-like variables). We find that Edwards thermodynamics is able to
describe the jamming transition (J-point). Using the ensemble formalism we
elucidate the following: (i)We test the combined volume-stress ensemble by
comparing the statistical properties of jammed configurations obtained by
dynamics with those averaged over the ensemble of minima in the potential
energy landscape as a test of ergodicity. Agreement between both methods
supports the idea of "thermalization" at a given angoricity and compactivity.
(ii) A microcanonical ensemble analysis supports the idea of maximum entropy
principle for grains. (iii) The intensive variables describe the approach to
jamming through a series of scaling relations as A {\to} 0+ and X {\to} 0-. Due
to the force-volume coupling, the jamming transition can be probed
thermodynamically by a "jamming temperature" TJ comprised of contributions from
A and X. (iv) The thermodynamic framework reveals the order of the jamming
phase transition by showing the absence of critical fluctuations at jamming in
observables like pressure and volume. (v) Finally, we elaborate on a comparison
with relevant studies showing a breakdown of equiprobability of microstates.Comment: 22pages, 24 figure
Addressing Childhood Obesity in Georgia: Past, Present, and Future
The Trust for America\u27s Health ranks Georgia 17th (16.5%) in the nation for childhood obesity prevalence among youth aged 10-17 years. Georgia has a long history of addressing childhood obesity at the state, regional, and local levels. This report outlines the historical efforts in childhood obesity in Georgia from the mid-1990’s to the present, summarizes current childhood obesity prevention and management strategies, and provides childhood obesity-related data relevant to the current strategies
Finite resolution measurement of the non-classical polarization statistics of entangled photon pairs
By limiting the resolution of quantum measurements, the measurement induced
changes of the quantum state can be reduced, permitting subsequent measurements
of variables that do not commute with the initially measured property. It is
then possible to experimentally determine correlations between non-commuting
variables. The application of this method to the polarization statistics of
entangled photon pairs reveals that negative conditional probabilities between
non-orthogonal polarization components are responsible for the violation of
Bell's inequalities. Such negative probabilities can also be observed in finite
resolution measurements of the polarization of a single photon. The violation
of Bell's inequalities therefore originates from local properties of the
quantum statistics of single photon polarization.Comment: 15 pages, 5 figures and 1 table, new figure to illustrate results,
improved explanation of statistical analysi
Speckle Statistics in Adaptively Corrected Images
(abridged) Imaging observations are generally affected by a fluctuating
background of speckles, a particular problem when detecting faint stellar
companions at small angular separations. Knowing the distribution of the
speckle intensities at a given location in the image plane is important for
understanding the noise limits of companion detection. The speckle noise limit
in a long-exposure image is characterized by the intensity variance and the
speckle lifetime. In this paper we address the former quantity through the
distribution function of speckle intensity. Previous theoretical work has
predicted a form for this distribution function at a single location in the
image plane. We developed a fast readout mode to take short exposures of
stellar images corrected by adaptive optics at the ground-based UCO/Lick
Observatory, with integration times of 5 ms and a time between successive
frames of 14.5 ms ( m). These observations temporally
oversample and spatially Nyquist sample the observed speckle patterns. We show,
for various locations in the image plane, the observed distribution of speckle
intensities is consistent with the predicted form. Additionally, we demonstrate
a method by which and can be mapped over the image plane. As the
quantity is proportional to the PSF of the telescope free of random
atmospheric aberrations, this method can be used for PSF calibration and
reconstruction.Comment: 7 pages, 4 figures, ApJ accepte
A New Measurement of the Average FUV Extinction Curve
We have measured the extinction curve in the far-ultraviolet wavelength
region of (900 -- 1200 A) using spectra obtained with the Berkeley EUV/FUV
spectrometer during the ORFEUS-I and the ORFEUS-II missions in 1993 and 1996.
From the complete sample of early-type stars observed during these missions,
we have selected pairs of stars with the same spectral type but different
reddenings to measure the differential FUV extinction. We model the effects of
molecular hydrogen absorption and exclude affected regions of the spectrum to
determine the extinction from dust alone. We minimize errors from inaccuracies
in the cataloged spectral types of the stars by making our own determinations
of spectral types based on their IUE spectra. We find substantial scatter in
the curves of individual star pairs and present a detailed examination of the
uncertainties and their effects on each extinction curve. We find that, given
the potentially large uncertainties inherent in using the pair method at FUV
wavelengths, a careful analysis of measurement uncertainties is critical to
assessing the true dust extinction. We present a new measurement of the average
far-ultraviolet extinction curve to the Lyman limit; our new measurement is
consistent with an extrapolation of the standard extinction curve of Savage &
Mathis (1979).Comment: 13 pages text, 7 figures 4 tables. Sent as gzipped tar, with ms.tex
and 7 figure
- …