843 research outputs found
CORRECTION OF FEMUR DEFORMITIES BY ILIZAROV METHOD AND BY APPARATUS «ORTHO-SUV» BASED ON COMPUTER NAVIGATION
Results of correction of femur deformations by Ilizarov method and with apparatus Orto-SuV working on the basis of computer navigation are analyzed. For elimination of difficult deformations in order to avoid multiple external fixator remounting with stage-by-stage radiological control it is expedient to use apparatus Orto-SUV. In order to elimination of moderate and simple deformations (except torsion) as hexapods and traditional techniques can be a choice method. The use «Orto-SUV» apparatus allows to reduce time necessary for deformation correction and osteosynthesis term in 1,4â2,4 times (for average and severe deformations)
Experimental Modeling of Combined and Sequential Use of Transosseous and Intramedullary Blocking Osteosynthesis
Background. The introduction of the combined and sequential application of transosseous and intramedullary blocked osteosynthesis in limb lengthening requires an experimental study of the features of distraction regenerate. For small animals (in particular rabbits), special models are required.Aims. To develop experimental models of sequential and combined use of transosseous and intramedullary osteosynthesis in limb lengthening and substantiate their effectiveness.Materials and methods. A comparative study was carried out on 30 rabbits of the Soviet Chinchilla breed. Experimental models of sequential (EM-1) and combined (EM-2) application of transosseous and intramedullary osteosynthesis with preservation of the apparatus during the fixation period to simulate blockage were studied in the main groups. For comparison, sequential (comparison model 1 â CM-1) and combined (comparison model 2 â CM-2) use of transosseous and intramedullary osteosynthesis with dismantling of the apparatus at the end of distraction were modeled. The control was a regenerate formed according to the classical Ilizarov method. Radiographs were performed in dynamics, CT and morphological studies â at the end of the fixation period.Results. It was noted that regenerates of the same type in structure were formed in the EM-1 and CM-1 groups, as in the EM-2 and CM-2 groups. With successive methods, the spindle-shaped form of the regenerate prevailed, the formation of a pronounced periosteal component was noted. Powerful cortical plates, according to morphological studies, are formed from the periosteal and intermediate zones. With combined techniques, the cortical plates are formed thinner and predominantly from the periosteal component, the shape of the regenerate is closer to fusiform. In the comparison groups, the total time of surgical interventions was 25â50 % longer, in 50 % of cases there was a loss of length or deformation of the regenerate.Conclusions. The developed models of sequential and combined use of transosseous and intramedullary osteosynthesis for limb lengthening with preservation of fixation with an apparatus to simulate blocking have proven to be reliable in terms of fixation and easy to use on small laboratory animals.
Measurement of the ratio of branching fractions BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma)
The ratio of branching fractions of the radiative B decays B0 -> K*0 gamma
and Bs0 -> phi gamma has been measured using 0.37 fb-1 of pp collisions at a
centre of mass energy of sqrt(s) = 7 TeV, collected by the LHCb experiment. The
value obtained is BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) = 1.12 +/- 0.08
^{+0.06}_{-0.04} ^{+0.09}_{-0.08}, where the first uncertainty is statistical,
the second systematic and the third is associated to the ratio of fragmentation
fractions fs/fd. Using the world average for BR(B0 -> K*0 gamma) = (4.33 +/-
0.15) x 10^{-5}, the branching fraction BR(Bs0 -> phi gamma) is measured to be
(3.9 +/- 0.5) x 10^{-5}, which is the most precise measurement to date.Comment: 15 pages, 1 figure, 2 table
Search for CP violation in decays
A model-independent search for direct CP violation in the Cabibbo suppressed
decay in a sample of approximately 370,000 decays is
carried out. The data were collected by the LHCb experiment in 2010 and
correspond to an integrated luminosity of 35 pb. The normalized Dalitz
plot distributions for and are compared using four different
binning schemes that are sensitive to different manifestations of CP violation.
No evidence for CP asymmetry is found.Comment: 13 pages, 8 figures, submitted to Phys. Rev.
Observation of excited Lambda_b0 baryons
Using pp collision data corresponding to 1.0 fb-1 integrated luminosity
collected by the LHCb detector, two narrow states are observed in the
Lambda_b0pi+pi- spectrum with masses 5911.97 +- 0.12(stat) +- 0.02(syst) +-
0.66(Lambda_b0 mass) MeV/c^2 and 5919.77 +- 0.08(stat) +- 0.02(syst) +-
0.66(Lambda_b0 mass) MeV/c^2. The significances of the observations are 5.2 and
10.2 standard deviations, respectively. These states are interpreted as the
orbitally-excited Lambda_b0 baryons, Lambda_b*0(5912) and Lambda_b*0(5920).Comment: Replaced by version published in Phys. Rev. Lett, modified fit with
better mass resolution treatmen
Strong constraints on the rare decays Bs -> mu+ mu- and B0 -> mu+ mu-
A search for Bs -> mu+ mu- and B0 -> mu+ mu- decays is performed using 1.0
fb^-1 of pp collision data collected at \sqrt{s}=7 TeV with the LHCb experiment
at the Large Hadron Collider. For both decays the number of observed events is
consistent with expectation from background and Standard Model signal
predictions. Upper limits on the branching fractions are determined to be BR(Bs
-> mu+ mu-) mu+ mu-) < 1.0 (0.81) x 10^-9 at
95% (90%) confidence level.Comment: 2+6 pages; 4 figures; Accepted for publication in Physical Review
Letter
Opposite-side flavour tagging of B mesons at the LHCb experiment
The calibration and performance of the oppositeside
flavour tagging algorithms used for the measurements
of time-dependent asymmetries at the LHCb experiment
are described. The algorithms have been developed using
simulated events and optimized and calibrated with
B
+ âJ/ÏK
+, B0 âJ/ÏK
â0 and B0 âD
ââ
Ό
+
ΜΌ decay
modes with 0.37 fbâ1 of data collected in pp collisions
at
â
s = 7 TeV during the 2011 physics run. The oppositeside
tagging power is determined in the B
+ â J/ÏK
+
channel to be (2.10 ± 0.08 ± 0.24) %, where the first uncertainty
is statistical and the second is systematic
Measurement of the CP-violating phase phi_s in the decay Bs->J/psi phi
We present a measurement of the time-dependent CP-violating asymmetry in B_s
-> J/psi phi decays, using data collected with the LHCb detector at the LHC.
The decay time distribution of B_s -> J/psi phi is characterized by the decay
widths Gamma_H and Gamma_L of the heavy and light mass eigenstates of the
B_s-B_s-bar system and by a CP-violating phase phi_s. In a sample of about 8500
B_s -> J/psi phi events isolated from 0.37 fb^-1 of pp collisions at sqrt(s)=7
TeV we measure phi_s = 0.15 +/- 0.18 (stat) +/- 0.06 (syst) rad. We also find
an average B_s decay width Gamma_s == (Gamma_L + Gamma_H)/2 = 0.657 +/- 0.009
(stat) +/- 0.008 (syst) ps^-1 and a decay width difference Delta Gamma_s ==
Gamma_L - Gamma_H} = 0.123 +/- 0.029 (stat) +/- 0.011 (syst) ps^-1. Our
measurement is insensitive to the transformation (phi_s,DeltaGamma_s --> pi -
phi_s, - Delta Gamma_s.Comment: 9 pages, 3 figure
Measurements of the branching fractions of the decays B°s â Dâs K± and B°s â DÂŻsÏ+
The decay mode B°s â Dâs K± allows for one of the theoretically cleanest measurements of the CKM angle Îł through the study of time-dependent CP violation. This paper reports a measurement of its branching fraction relative to the Cabibbo-favoured mode B°s â DÂŻsÏ+ based on a data sample corresponding to 0.37 fbÂŻÂč of proton-proton collisions at âs = 7TeV collected in 2011 with the LHCb detector. In addition, the ratio of B meson production fractions fs/fd, determined from semileptonic decays, together with the known branching fraction of the control channel B°s â DÂŻsÏ+ is used to perform an absolute measurement of the branching fractions: B(B°s â DÂŻsÏ+) = (2.95 ± 0.05 ± 0.17 -0.22 +0.18) Ă 10ÂŻÂł ; B(B°s â Dâs K±) = (1.90 ± 0.12 ± 0.13 -0.14 +0.12) Ă 10ÂŻ4 ; where the first uncertainty is statistical, the second the experimental systematic uncertainty, and the third the uncertainty due to f s/f
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