256 research outputs found
Influence of Primary Cosmic Radiation Mass Composition on the Estimation of Eas Energy
At the Yakutsk EAS array E_em is determined by using measurements of EAS
Cherenkov light flux and charged particle flux. It is known from calculations
that these characteristics depend on a sort of primary particle and, therefore,
the estimation of E_em depends on a primary particle mass. In the work the
dependence of the E_em/E_0 ratio on the energy is given and experimental data
are compared with calculations by the QGSJET model. The calculations have been
carried out for the primary proton and iron nucleus. The average calculated
meaning of the value of E_em/E_0 ratio (between the proton and iron nucleus)
within experimental errors is in agreement with experimental data that doesnt
contradict to the mixed mass composition of primary cosmic radiation.Comment: 19th European Cosmic Ray Symposium. Aug 30 - Sep 3 2004, Florence,
Italy. 3 pages, 1 figure. Subbmitted for publication in International Journal
of Modern Physics
Fluctuations of Xmax and Primary Particle Mass Composition in the Range of Energy 5 10^{17} - 3 10^{19} ev by Yakutsk Data
The experimental distributions of \Xmax obtained with the Yakutsk EAS array
at fixed energies of , and
eV are analysed. A recent version of the QGSJET model is used as a tool of our
analysis. In the framework of this model, the most adequate mass composition of
primary particles satisfying the experimental data on \Xmax is selected.Comment: 19th European Cosmic Ray Symposium, Aug 30 - Sep 3 2004, Florence,
Italy. 3 pages, 1 figure. Submitted for publication in International Journal
of Modern Physics
Muons with E_th >= 1 Gev and Mass Composition in the Energy Range 10^{18}-10^{20} ev Observed by Yakutsk Eas Array
The ratio of the muon flux density to charged particle flux density at
distances of 300 and 600 m from the shower axis (\rhom(300)/\rhos(300) and
\rhom(600)/\rhos(600)) is measured. In addition, the energy dependence of
\rhom(1000) is analysed for showers with energies above eV. A
comparison between the experimental data and calculations performed with the
QGSJET model is given for the cases of primary proton, iron nucleus and gamma-
ray. We conclude that the showers with \E\ge3\times10^{18} eV can be formed
by light nuclei with a pronounced fraction of protons and helium nuclei. It is
not excluded however that a small part of showers with energies above
eV could be initiated by primary gamma-rays.Comment: 19th European Cosmic Ray Symposium, Aug 30 - Sep 3 2004, Florence,
Italy. 3 pages, 1 figure. Submitted for publication in International Journal
of Modern Physics
Structure of (22\u3cem\u3eS\u3c/em\u3e)-3\u3cem\u3eβ\u3c/em\u3e-Acetoxy-20-(3-isopropylisoxazolin-5-yl)-4,4,14 \u3cem\u3eα\u3c/em\u3e-trimethylpregn-8(9)-ene
C32H51NO3, Mr = 497·7, orthorhombic, P212121, a = 7·577 (2), b = 10·510 (2), c = 35·399 (7) Å, V = 2819 (1) Å3, Z = 4, Dx = 1·173 g cm-3, λ (Mo Kα) = 0·71073 Å, μ = 0·69 cm-1, F(000) = 1096, T = 153 K, R = 0·0497 for 2235 observed reflections. The compound investigated is found to be a (22S)-epimer
\u3cem\u3eβ\u3c/em\u3e-Homopipitzolone
The structure of β-homopipitzolone (one of the two isomers of an intermediate product in the homocedrole synthesis) has been unequivocally established as 1 O-hydroxy-2,6,9-trimetbyltricyclo[6.3.1.01,6] dodeca-9-ene-5, II, 12-trione with relative IR,2R,6R,8S configuration
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Which prosthetic foot to prescribe? Biomechanical differences found during a single session comparison of different foot types hold true one year later
YesIntroduction: Clinicians typically use findings from cohort studies to objectively inform judgements regarding the potential (dis)advantages of prescribing a new prosthetic device. However, before finalising prescription a clinician will typically ask a patient to ‘try out’ a change of prosthetic device while the patient is at the clinic. Observed differences in gait when using the new device should be the result of the device’s mechanical function, but could also conceivably be due to patient related factors which can change from day-to-day and can thus make device comparisons unreliable. To determine whether a device’s mechanical function consistently has a more meaningful impact on gait than patient-related factors, the present study undertook quantitative gait analyses of a trans-tibial amputee walking using two different foot-ankle devices on two occasions over a year apart. If the observed differences present between devices, established using quantitative gait analysis, were in the same direction and of similar magnitude on each of the two occasions, this would indicate that device-related factors were more important than patient-related factors.
Methods: One adult male with a unilateral trans-tibial amputation completed repeated walking trials using two different prosthetic foot devices on two separate occasions, 14 months apart. Walking speed and sagittal plane joint kinematics and kinetics for both limbs were assessed on each occasion. Clinically meaningful differences in these biomechanical outcome variables were defined as those with an effect size difference (d) between prosthetic conditions of at least 0.4 (i.e. ‘medium’ effect size).
Results: Eight variables namely, walking speed, prosthetic ‘ankle’ peak plantar- and dorsi- flexion and peak positive power, and residual knee loading response flexion, peak stance-phase extension and flexion moments and peak negative power, displayed clinically meaningful differences (d > 0.4) between foot devices during the first session. All eight of these showed similar effect size differences during the second session despite the participant being heavier and older.
Conclusions: Findings suggest that a prosthetic device’s mechanical function consistently has a more meaningful impact on gait than patient-related factors. These findings support the current clinical practice of making decisions regarding prosthetic prescription for an individual, based on a single session evaluation of their gait using two different devices. However, to confirm this conclusion, a case series using the same approach as the present study could be undertaken
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