524 research outputs found
Impulse oscillometry may be of value in detecting early manifestations of COPD
SummaryBackgroundSpirometry is used to diagnose chronic obstructive pulmonary disease (COPD). The Impulse oscillometry system (IOS) allows determination of respiratory impedance indices, which might be of potential value in early COPD, although previous experience is limited. We examined pulmonary resistance and reactance measured by IOS in subjects with or without self-reported chronic bronchitis or emphysema or COPD (Q+ or Q−) and subjects with or without COPD diagnosed according to the Global Initiative for Chronic Obstructive Lung Disease (GOLD) criteria (G+ or G−).MethodsFrom a previous population-based study 450 subjects were examined with spirometry and IOS and answered a questionnaire on respiratory symptoms and diseases.ResultsSeventy-seven subjects were Q+, of whom 34 also were G+. Q+/G− subjects (n = 43) reported respiratory symptoms more frequently (35–40% vs 8–14%) but had higher FEV1 (100% vs 87%) than Q−/G+ subjects (n = 90), p < 0.05 for both comparisons. Q+ subjects had higher pulmonary resistance and lower pulmonary reactance than Q− subjects (p < 0.01 for all comparisons). The same pattern was seen both in G+ subjects ((Q+/Q−) R5 0.39/0.32, R5–R20 0.10/0.07, X5 0.13/0.09, AX 0.55/0.27, p < 0.05 for all) and G− subjects ((Q+/Q−) R5 0.35/0.29, R5–R20 0.08/0.06, X5 0.10/0.08, AX 0.31/0.19 p < 0.05 for all) except for R20 (adjusted for gender and age).ConclusionsSelf-reported chronic bronchitis or emphysema or COPD was associated with higher pulmonary resistance and lower pulmonary reactance measured by IOS, both among subjects with and without COPD according to GOLD criteria. IOS may have the potential to detect pathology associated with COPD earlier than spirometry
Ultra-low power signal processing
This IEEE Signal Processing Magazine (SPM) forum discusses the latest advances and challenges in ultra-low power (ULP) signal processing (SP). The forum members bring their expert insights to issues such as design requirements and future applications of ULP SP systems. The invited forum members are Gene Frantz (Texas Instruments), Jorg Henkel (Karlsruhe Institute of Technology), Jan Rabaey (University of California at Berkeley), Todd Schneider (ON Semiconductor), and Marilyn Wolf (Georgia Institute of Technology). The moderator of the forum is Umit Batur (Texas Instruments). Our readers may agree or disagree with the ideas discussed next. In either case, we invite you to share your comments with us by e-mailing [email protected] or spm.columns. [email protected]. © 2006 IEEE
Thermodynamics of Na_8 and Na_{20} clusters studied with ab-initio electronic structure methods
We study the thermodynamics of Na_8 and Na_{20} clusters using
multiple-histogram methods and an ab initio treatment of the valence electrons
within density functional theory. We consider the influence of various electron
kinetic-energy functionals and pseudopotentials on the canonical ionic specific
heats. The results for all models we consider show qualitative similarities,
but also significant temperature shifts from model to model of peaks and other
features in the specific-heat curves. The use of phenomenological
pseudopotentials shifts the melting peak substantially (~ 50--100 K) when
compared to ab-initio results. It is argued that the choice of a good
pseudopotential and use of better electronic kinetic-energy functionals has the
potential for performing large time scale and large sized thermodynamical
simulations on clusters.Comment: LaTeX file and EPS figures. 24 pages, 13 figures. Submitted to Phys.
Rev.
Thermal Dileptons at LHC
We predict dilepton invariant-mass spectra for central 5.5 ATeV Pb-Pb
collisions at LHC. Hadronic emission in the low-mass region is calculated using
in-medium spectral functions of light vector mesons within hadronic many-body
theory. In the intermediate-mass region thermal radiation from the Quark-Gluon
Plasma, evaluated perturbatively with hard-thermal loop corrections, takes
over. An important source over the entire mass range are decays of correlated
open-charm hadrons, rendering the nuclear modification of charm and bottom
spectra a critical ingredient.Comment: 2 pages, 2 figures, contributed to Workshop on Heavy Ion Collisions
at the LHC: Last Call for Predictions, Geneva, Switzerland, 14 May - 8 Jun
2007 v2: acknowledgment include
Identified charged hadron production in p+p collisions at sqrt(s)=200 and 62.4 GeV
Transverse momentum distributions and yields for , ,
and in collisions at =200 and 62.4 GeV at midrapidity
are measured by the PHENIX experiment at the Relativistic Heavy Ion Collider
(RHIC). These data provide important baseline spectra for comparisons with
identified particle spectra in heavy ion collisions at RHIC. We present the
inverse slope parameter , mean transverse momentum and
yield per unit rapidity at each energy, and compare them to other
measurements at different in and collisions. We
also present the scaling properties such as scaling, scaling on the
spectra between different energies. To discuss the mechanism of the
particle production in collisions, the measured spectra are compared to
next-to-leading-order or next-to-leading-logarithmic perturbative quantum
chromodynamics calculations.Comment: 431 authors from 62 institutions, 32 pages, 23 figures, and 18
tables. Submitted to Physical Review C. Plain text data tables for the points
plotted in figures for this and previous PHENIX publications are (or will be)
publicly available at http://www.phenix.bnl.gov/papers.htm
Measurement of jet-medium interactions via direct photon-hadron correlations in AuAu and Au collisions at GeV
We present direct photon-hadron correlations in 200 GeV/A AuAu, Au
and collisions, for direct photon from 5--12 GeV/, collected
by the PHENIX Collaboration in the years from 2006 to 2011. We observe no
significant modification of jet fragmentation in Au collisions,
indicating that cold nuclear matter effects are small or absent. Hadrons
carrying a large fraction of the quark's momentum are suppressed in AuAu
compared to and Au. As the momentum fraction decreases, the
yield of hadrons in AuAu increases to an excess over the yield in
collisions. The excess is at large angles and at low hadron and is most
pronounced for hadrons associated with lower momentum direct photons.
Comparison to theoretical calculations suggests that the hadron excess arises
from medium response to energy deposited by jets.Comment: 578 authors from 80 institutions, 11 pages, 7 figures, data from
2007, 2008, 2010, and 2011. v2 is version accepted for publication in
Physical Review C. Plain text data tables for the points plotted in figures
for this and previous PHENIX publications are (or will be) publicly available
at http://www.phenix.bnl.gov/papers.htm
Production of and mesons in UU collisions at GeV
The PHENIX experiment at the Relativistic Heavy Ion Collider measured
and mesons at midrapidity in UU collisions at
GeV in a wide transverse momentum range. Measurements were performed in the
decay modes. A strong suppression of
and meson production at high transverse momentum was observed in
central UU collisions relative to binary scaled results. Yields of
and mesons measured in UU collisions show similar suppression
pattern to the ones measured in AuAu collisions at
GeV for similar numbers of participant nucleons. The / ratios do
not show dependence on centrality or transverse momentum, and are consistent
with previously measured values in hadron-hadron, hadron-nucleus,
nucleus-nucleus, and collisions.Comment: 403 authors from 72 institutions, 13 pages, 6 figures, 7 tables, 2012
data. v2 is version accepted by Physical Review C. Plain text data tables for
the points plotted in figures for this and previous PHENIX publications are
(or will be) publicly available at http://www.phenix.bnl.gov/papers.htm
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