430 research outputs found
Методика неинвазивного мониторинга дыхательного паттерна у больных бронхиальной астмой
Impedance pneumography (IP) system for breathing pattern monitoring was developed. IP system was calibrated volumetrically using integrated pneumotachigraphy. We studied mean breathing pattern parameters in 39 healthy subjects, patients with mild (n=39), moderate (n=25) and severe (n=17) bronchial asthma (BA) in sitting posture during 10 min. interval. Mean breathing rate was significantly (p<0.05) higher in all BA groups (18.0±0.6, 18.0±0.6, 20.4±1.2 /min., M±m) than in controls (16,2±0,6 /min.). Patients with severe BA demonstrated significantly higher mean partial expiratory time (58.2±0.8%) and lower mean tidal volume (0.35±0.04 I) than healthy subjects (55.8±0.5% and 0.47±0.02 I, respectively). We concluded that developed noninvasive breathing pattern monitoring method is informative in patients with BA.Разработана методика автоматизированного неинвазивного мониторинга дыхательного паттерна методом импедансной пневмографии, калиброванной в единицах объема вентиляции, с помощью интегрированной пневмотахограммы. Проведено сравнительное исследование средних величин параметров дыхательного паттерна у 39 здоровых лиц и больных бронхиальной астмой (БА) с легким (л=39), среднетяжелым (п=25) и тяжелым (л=17) течением заболевания в положении сидя за 10 мин. Во всех группах больных БА средняя частота дыхания (18,0±0,6, 18,0±0,6, 20,4±1,2 в 1 мин, М ±т) была достоверно (р<0,05) выше, чем в контроле (16,2±0,6 в 1 мин). В группе с тяжелым течением БА наблюдалось достоверное увеличение среднего относительного времени выдоха в дыхательном цикле (58,2±0,8%) и уменьшение среднего дыхательного объема (0,35±0,04 л) относительно контроля (55,8±0,5% и 0,47±0,02 л соответственно). Сделан вывод о информативности разработанной методики для мониторинга вентиляции легких у больных БА
Longitudinal Spin Transfer to and Hyperons in Polarized Proton-Proton Collisions at = 200 GeV
The longitudinal spin transfer, , from high energy polarized protons
to and hyperons has been measured for the first time
in proton-proton collisions at with the STAR
detector at RHIC. The measurements cover pseudorapidity, , in the range
and transverse momenta, , up to . The longitudinal spin transfer is found to be for inclusive
and for
inclusive hyperons with and . The dependence on and is presented.Comment: 5 pages, 4 figure
An Experimental Exploration of the QCD Phase Diagram: The Search for the Critical Point and the Onset of De-confinement
The QCD phase diagram lies at the heart of what the RHIC Physics Program is
all about. While RHIC has been operating very successfully at or close to its
maximum energy for almost a decade, it has become clear that this collider can
also be operated at lower energies down to 5 GeV without extensive upgrades. An
exploration of the full region of beam energies available at the RHIC facility
is imperative. The STAR detector, due to its large uniform acceptance and
excellent particle identification capabilities, is uniquely positioned to carry
out this program in depth and detail. The first exploratory beam energy scan
(BES) run at RHIC took place in 2010 (Run 10), since several STAR upgrades,
most importantly a full barrel Time of Flight detector, are now completed which
add new capabilities important for the interesting physics at BES energies. In
this document we discuss current proposed measurements, with estimations of the
accuracy of the measurements given an assumed event count at each beam energy.Comment: 59 pages, 78 figure
Measurements of Dihadron Correlations Relative to the Event Plane in Au+Au Collisions at GeV
Dihadron azimuthal correlations containing a high transverse momentum (\pt)
trigger particle are sensitive to the properties of the nuclear medium created
at RHIC through the strong interactions occurring between the traversing parton
and the medium, i.e. jet-quenching. Previous measurements revealed a strong
modification to dihadron azimuthal correlations in Au+Au collisions with
respect to \pp\ and \dAu\ collisions. The modification increases with the
collision centrality, suggesting a path-length dependence to the jet-quenching
effect. This paper reports STAR measurements of dihadron azimuthal correlations
in mid-central (20-60\%) Au+Au collisions at \snn=200~GeV as a function of
the trigger particle's azimuthal angle relative to the event plane,
\phis=|\phit-\psiEP|. The azimuthal correlation is studied as a function of
both the trigger and associated particle \pt. The subtractions of the
combinatorial background and anisotropic flow, assuming Zero Yield At Minimum
(\zyam), are described. The away-side correlation is strongly modified, and the
modification varies with \phis, which is expected to be related to the
path-length that the away-side parton traverses. The pseudo-rapidity (\deta)
dependence of the near-side correlation, sensitive to long range \deta
correlations (the ridge), is also investigated. The ridge and jet-like
components of the near-side correlation are studied as a function of \phis.
The ridge appears to drop with increasing \phis while the jet-like component
remains approximately constant. ...Comment: 50 pages, 39 figures, 6 table
Studies of di-jet survival and surface emission bias in Au+Au collisions via angular correlations with respect to back-to-back leading hadrons
We report first results from an analysis based on a new multi-hadron
correlation technique, exploring jet-medium interactions and di-jet surface
emission bias at RHIC. Pairs of back-to-back high transverse momentum hadrons
are used for triggers to study associated hadron distributions. In contrast
with two- and three-particle correlations with a single trigger with similar
kinematic selections, the associated hadron distribution of both trigger sides
reveals no modification in either relative pseudo-rapidity or relative
azimuthal angle from d+Au to central Au+Au collisions. We determine associated
hadron yields and spectra as well as production rates for such correlated
back-to-back triggers to gain additional insights on medium properties.Comment: By the STAR Collaboration. 6 pages, 2 figure
Observation of the antimatter helium-4 nucleus
High-energy nuclear collisions create an energy density similar to that of
the universe microseconds after the Big Bang, and in both cases, matter and
antimatter are formed with comparable abundance. However, the relatively
short-lived expansion in nuclear collisions allows antimatter to decouple
quickly from matter, and avoid annihilation. Thus, a high energy accelerator of
heavy nuclei is an efficient means of producing and studying antimatter. The
antimatter helium-4 nucleus (), also known as the anti-{\alpha}
(), consists of two antiprotons and two antineutrons (baryon
number B=-4). It has not been observed previously, although the {\alpha}
particle was identified a century ago by Rutherford and is present in cosmic
radiation at the 10% level. Antimatter nuclei with B < -1 have been observed
only as rare products of interactions at particle accelerators, where the rate
of antinucleus production in high-energy collisions decreases by about 1000
with each additional antinucleon. We present the observation of the antimatter
helium-4 nucleus, the heaviest observed antinucleus. In total 18
counts were detected at the STAR experiment at RHIC in 10 recorded Au+Au
collisions at center-of-mass energies of 200 GeV and 62 GeV per nucleon-nucleon
pair. The yield is consistent with expectations from thermodynamic and
coalescent nucleosynthesis models, which has implications beyond nuclear
physics.Comment: 19 pages, 4 figures. Submitted to Nature. Under media embarg
Inclusive pi^0, eta, and direct photon production at high transverse momentum in p+p and d+Au collisions at sqrt(s_NN) = 200 GeV
We report a measurement of high-p_T inclusive pi^0, eta, and direct photon
production in p+p and d+Au collisions at sqrt(s_NN) = 200 GeV at midrapidity (0
gamma gamma were detected in the
Barrel Electromagnetic Calorimeter of the STAR experiment at the Relativistic
Heavy Ion Collider. The eta -> gamma gamma decay was also observed and
constituted the first eta measurement by STAR. The first direct photon cross
section measurement by STAR is also presented, the signal was extracted
statistically by subtracting the pi^0, eta, and omega(782) decay background
from the inclusive photon distribution observed in the calorimeter. The
analysis is described in detail, and the results are found to be in good
agreement with earlier measurements and with next-to-leading order perturbative
QCD calculations.Comment: 28 pages, 30 figures, 6 tables, the updated version that was accepted
by Phys. Rev.
Charged and strange hadron elliptic flow in Cu+Cu collisions at = 62.4 and 200 GeV
We present the results of an elliptic flow analysis of Cu+Cu collisions
recorded with the STAR detector at 62.4 and 200GeV. Elliptic flow as a function
of transverse momentum is reported for different collision centralities for
charged hadrons and strangeness containing hadrons , ,
, in the midrapidity region . Significant reduction in
systematic uncertainty of the measurement due to non-flow effects has been
achieved by correlating particles at midrapidity, , with those at
forward rapidity, . We also present azimuthal correlations in
p+p collisions at 200 GeV to help estimating non-flow effects. To study the
system-size dependence of elliptic flow, we present a detailed comparison with
previously published results from Au+Au collisions at 200 GeV. We observe that
() of strange hadrons has similar scaling properties as were
first observed in Au+Au collisions, i.e.: (i) at low transverse momenta,
, scales with transverse kinetic energy, , and
(ii) at intermediate , , it scales with the number of
constituent quarks, . We have found that ideal hydrodynamic calculations
fail to reproduce the centrality dependence of () for
and . Eccentricity scaled values, , are larger
in more central collisions, suggesting stronger collective flow develops in
more central collisions. The comparison with Au+Au collisions which go further
in density shows depend on the system size, number of
participants . This indicates that the ideal hydrodynamic limit is
not reached in Cu+Cu collisions, presumably because the assumption of
thermalization is not attained.Comment: 18 pages, 14 figure
Identified high- spectra in Cu+Cu collisions at =200 GeV
We report new results on identified (anti)proton and charged pion spectra at
large transverse momenta (3<<10 GeV/c) from Cu+Cu collisions at
=200 GeV using the STAR detector at the Relativistic Heavy Ion
Collider (RHIC). This study explores the system size dependence of two novel
features observed at RHIC with heavy ions: the hadron suppression at
high- and the anomalous baryon to meson enhancement at intermediate
transverse momenta. Both phenomena could be attributed to the creation of a new
form of QCD matter. The results presented here bridge the system size gap
between the available pp and Au+Au data, and allow the detailed exploration for
the on-set of the novel features. Comparative analysis of all available 200 GeV
data indicates that the system size is a major factor determining both the
magnitude of the hadron spectra suppression at large transverse momenta and the
relative baryon to meson enhancement.Comment: Submitted to Phys. Rev. C, 9 pages, 5 figure
Growth of Long Range Forward-Backward Multiplicity Correlations with Centrality in Au+Au Collisions at = 200 GeV
Forward-backward multiplicity correlation strengths have been measured with
the STAR detector for Au+Au and collisions at =
200 GeV. Strong short and long range correlations (LRC) are seen in central
Au+Au collisions. The magnitude of these correlations decrease with decreasing
centrality until only short range correlations are observed in peripheral Au+Au
collisions. Both the Dual Parton Model (DPM) and the Color Glass Condensate
(CGC) predict the existence of the long range correlations. In the DPM the
fluctuation in the number of elementary (parton) inelastic collisions produces
the LRC. In the CGC longitudinal color flux tubes generate the LRC. The data is
in qualitative agreement with the predictions from the DPM and indicates the
presence of multiple parton interactions.Comment: 6 pages, 3 figures The abstract has been slightly modifie
- …