98 research outputs found
Роль дисплазии гленоида в патогенезе хронической нестабильности плечевого сустава
The purpose - to analyze computerized tomography data in patients with recurrent shoulder instability for signs of glenoid dysplasia. Methods. We studied the diagnostic data and the results of surgical treatment of 168 patients (137 men and 31 women) mostly of young age (under 30 years) who addressed to the clinic during the period from 2010 to 2014 with the symptoms of recurrent anterior shoulder instability. A risk group has been defined with alleged glenoid dysplasia in the amount of 27 patients who were studied by glenoid dimensions (height, width, area), glenoid version (anteversion, retroversion) and inclination angle of the glenoid. Results. In 22 cases, there has been a change in the normal anatomy of the glenoid as its excessive anteversion, increased angle of inclination, and decrease of its absolute area. Research has identified a pathogenic role of changes in the normal anatomy of the glenoid because recurrence of chronic instability in some cases after surgery, as well as in cases of nontraumatic instability in patients without anatomic lesions. Conclusions. Dysplastic changes of bony structures of the shoulder represent the risk factor for recurrent instability and can serve as one of the causes of recurrence after surgical treatment. When choosing a treatment strategy in patients of modern population is advisable to suggest the possible presence of dysplastic changes glenoid. In the event of recurrence after surgical treatment is shown holding computerized tomography to rule out dysplastic changes.Цель исследования - выявление признаков дисплазии гленоида у пациентов с хронической нестабильностью плечевого сустава на основании данных компьютерной томографии. Материал и методы. Были изучены диагностические данные и результаты хирургического лечения 168 пациентов (137 мужчин и 31 женщина) преимущественно молодого возраста (до 30 лет), обратившихся в клинику в период с 2010 по 2014 г. по поводу симптомов рецидивирующей передней нестабильности плечевого сустава. Была выделена группа пациентов с предполагаемой дисплазией гленоида в количестве 27 пациентов, у которых были изучены размеры гленоида (высота, ширина, площадь), поворот (антеверсия, ретроверсия) и угол наклона гленоида. Результаты. В 22 случаях имело место изменение нормальной анатомии гленоида в виде его избыточной антеверсии, увеличенного угла наклона либо уменьшение его абсолютной площади. Исследование позволило определить патогенетическую роль измененной нормальной анатомии гленоида в развитии рецидивов хронической нестабильности в некоторых случаях после оперативного лечения, а также в случаях развития нетравматической нестабильности у пациентов без анатомических повреждений. Выводы. Диспластические изменения костных структур плечевого сустава являются фактором риска развития хронической нестабильности и могут служить одной из причин рецидивов после оперативного лечения. При выборе тактики лечения у пациентов современной популяции целесообразно предполагать наличие диспла- стических изменений гленоида. При возникновении рецидивов после оперативного лечения показано проведение компьютерной томографии для исключения диспластических изменений
Foliations of Isonergy Surfaces and Singularities of Curves
It is well known that changes in the Liouville foliations of the isoenergy
surfaces of an integrable system imply that the bifurcation set has
singularities at the corresponding energy level. We formulate certain
genericity assumptions for two degrees of freedom integrable systems and we
prove the opposite statement: the essential critical points of the bifurcation
set appear only if the Liouville foliations of the isoenergy surfaces change at
the corresponding energy levels. Along the proof, we give full classification
of the structure of the isoenergy surfaces near the critical set under our
genericity assumptions and we give their complete list using Fomenko graphs.
This may be viewed as a step towards completing the Smale program for relating
the energy surfaces foliation structure to singularities of the momentum
mappings for non-degenerate integrable two degrees of freedom systems.Comment: 30 pages, 19 figure
Pion, kaon, proton and anti-proton transverse momentum distributions from p+p and d+Au collisions at GeV
Identified mid-rapidity particle spectra of , , and
from 200 GeV p+p and d+Au collisions are reported. A
time-of-flight detector based on multi-gap resistive plate chamber technology
is used for particle identification. The particle-species dependence of the
Cronin effect is observed to be significantly smaller than that at lower
energies. The ratio of the nuclear modification factor () between
protons and charged hadrons () in the transverse momentum
range GeV/c is measured to be
(stat)(syst) in minimum-bias collisions and shows little
centrality dependence. The yield ratio of in minimum-bias d+Au
collisions is found to be a factor of 2 lower than that in Au+Au collisions,
indicating that the Cronin effect alone is not enough to account for the
relative baryon enhancement observed in heavy ion collisions at RHIC.Comment: 6 pages, 4 figures, 1 table. We extended the pion spectra from
transverse momentum 1.8 GeV/c to 3. GeV/
Azimuthal anisotropy and correlations in p+p, d+Au and Au+Au collisions at 200 GeV
We present the first measurement of directed flow () at RHIC. is
found to be consistent with zero at pseudorapidities from -1.2 to 1.2,
then rises to the level of a couple of percent over the range . The latter observation is similar to data from NA49 if the SPS rapidities
are shifted by the difference in beam rapidity between RHIC and SPS.
Back-to-back jets emitted out-of-plane are found to be suppressed more if
compared to those emitted in-plane, which is consistent with {\it jet
quenching}. Using the scalar product method, we systematically compared
azimuthal correlations from p+p, d+Au and Au+Au collisions. Flow and non-flow
from these three different collision systems are discussed.Comment: Quark Matter 2004 proceeding, 4 pages, 3 figure
Azimuthal anisotropy: the higher harmonics
We report the first observations of the fourth harmonic (v_4) in the
azimuthal distribution of particles at RHIC. The measurement was done taking
advantage of the large elliptic flow generated at RHIC. The integrated v_4 is
about a factor of 10 smaller than v_2. For the sixth (v_6) and eighth (v_8)
harmonics upper limits on the magnitudes are reported.Comment: 4 pages, 6 figures, contribution to the Quark Matter 2004 proceeding
All-optical switching and strong coupling using tunable whispering-gallery-mode microresonators
We review our recent work on tunable, ultrahigh quality factor
whispering-gallery-mode bottle microresonators and highlight their applications
in nonlinear optics and in quantum optics experiments. Our resonators combine
ultra-high quality factors of up to Q = 3.6 \times 10^8, a small mode volume,
and near-lossless fiber coupling, with a simple and customizable mode structure
enabling full tunability. We study, theoretically and experimentally, nonlinear
all-optical switching via the Kerr effect when the resonator is operated in an
add-drop configuration. This allows us to optically route a single-wavelength
cw optical signal between two fiber ports with high efficiency. Finally, we
report on progress towards strong coupling of single rubidium atoms to an
ultra-high Q mode of an actively stabilized bottle microresonator.Comment: 20 pages, 24 figures. Accepted for publication in Applied Physics B.
Changes according to referee suggestions: minor corrections to some figures
and captions, clarification of some points in the text, added references,
added new paragraph with results on atom-resonator interactio
Strange Resonance Production in p+p and Au+Au Collisions at RHIC Energies
Resonance yields and spectra from elementary p+p and Au+Au collisions at
200 GeV from the STAR experiment at RHIC are presented
and discussed in terms of chemical and thermal freeze-out conditions. Thermal
models do not adequately describe the yields of the resonance production in
central Au+Au collisions. The approach to include elastic hadronic interactions
between chemical freeze-out and thermal freeze-out suggests a time of 5 fm/c.Comment: 4 pages, 7 figures, proceedings of the Quark Matter 2004, in Oakland,
California, to be published in Journal of Physics G: Nuclear and Particle
Physic
Identified particles at large transverse momenta in STAR in Au+Au collisions @ sqrt(s_NN) = 200 GeV
We report measurements of the ratios of identified hadrons (pi,K,p,Lambda) in
Au+Au collisions at sqrt(s_NN) = 200 GeV as a function of both collision
centrality and transverse momentum (p_T). Ratios of anti-baryon to baryon
yields are independent of p_T within 2<p_T <6 GeV/c indicating that, for such a
range, our measurements are inconsistent with theoretical pQCD calculations
predicting a decrease due to a stronger contribution from valence quark
scattering. For both strange and non-strange species, a strong baryon
enhancement relative to meson yields is observed as a function of collision
centrality in this intermediate p_T region, leading to p/pi and Lambda/K ratios
greater than unity. The nuclear modification factor, R_cp (central relative to
peripheral collisions), is used to illustrate the interplay between jet
quenching and hadron production. The physics implications of these measurements
are discussed with reference to different theoretical models.Comment: 5 pages, 4 figures. Proceedings of Quark Matter 2004 Conference, Jan
2004, Oakland, USA. Submitted to Journal of Physics
High- electron distributions in d+Au and p+p collisions at RHIC
We present preliminary measurements of electron and positron spectra in d+Au
and p+p collisions at GeV for GeV/c.
These measurements were carried out using the STAR Time Projection Chamber
(TPC) and the Barrel Electromagnetic calorimeter (EMC). Overall hadron
rejection factors in the range of have been achieved. In this work we
describe the measurement technique used to discriminate electrons from hadrons
and compare the results for single electron spectra with Pythia based pQCD
calculations for electrons from heavy-quark semi-leptonic decays.Comment: Quark Matter 2004 conference proceeding
Measurement of open charm production in +Au collisions at =200 GeV
We present the first comprehensive measurement of and
their charge conjugate states at mid-rapidity in +Au collisions at
=200 GeV using the STAR TPC. The directly measured open charm
multiplicity distribution covers a broad transverse momentum region of
0 GeV/. The measured at mid-rapidity for is
and the measured
and ratios are approximately equal with a magnitude of . The total cross section per
nucleon-nucleon collision extracted from this study is mb. The direct measurement of open charm production is
consistent with STAR single electron data. This cross section is higher than
expectations from PYTHIA and other pQCD calculations. The measured
distribution is harder than the pQCD prediction using the Peterson
fragmentation function.Comment: Quark Matter 2004 Proceeding
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