537 research outputs found

    MULTI-PLANAR ANALYSIS OF THE TRADITIONAL BACK SQUAT AND SMITH MACHINE BACK SQUAT

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    This study evaluated the kinetic differences between the traditional back squat (T-BS) and Smith machine back squat (SM-BS) performed at a variety of loads. Ten subjects were tested in six conditions including the T-BS and SM-BS each performed at 50%, 80%, and 100% of the subject’s five repetition maximum load on a force platform. The analysis of vertical ground reaction forces (GRF) revealed significant main effects for exercise load (p ≤ 0.001) but not for squat condition or the interaction of load and squat condition (p \u3e 0.05). The analysis of sagittal plane GRF revealed significant main effects for exercise load (p ≤ 0.05), squat condition (p ≤ 0.001), and the interaction between load and condition (p ≤ 0.05). The analysis of frontal plane GRF revealed no main effects (p \u3e 0.05). The SM-BS offers the user a resistance stimuli in the sagittal plane against which the exerciser can produce greater sagittal force

    KINETIC AND SUBJECTIVE ANALYSIS OF KNEE ROLLERS, HANDS FREE CRUTCH, AND CONVENTIONAL CRUTCHES

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    This study assessed the kinetic demands of ambulatory assistance devices and the subject’s perceptions of each. Twelve subjects used a knee roller (KR), a hands free crutch (HFC), and conventional axillary crutches (CC), while walking over a force platform. Ground reaction forces (GRF) were obtained for each device for the unaffected and the affected limb. Significant differences in GRF for each device were found for each limb (p ≤ 0.001). No gender interaction was found (p \u3e 0.05). The GRF of the un-affected limb was highest for the CC and lowest for the KR (p ≤ 0.05). The GRF of the affected limb was higher for the KR compared to the HFC (p =.045). For the unaffected limb, the CC produced 45% more kinetic demand than the KR, and 11% more than the HFC. However, the qualitative analysis suggested that the CC and KR were favored over the HFC

    Quasiparticles of strongly correlated Fermi liquids at high temperatures and in high magnetic fields

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    Strongly correlated Fermi systems are among the most intriguing, best experimentally studied and fundamental systems in physics. There is, however, lack of theoretical understanding in this field of physics. The ideas based on the concepts like Kondo lattice and involving quantum and thermal fluctuations at a quantum critical point have been used to explain the unusual physics. Alas, being suggested to describe one property, these approaches fail to explain the others. This means a real crisis in theory suggesting that there is a hidden fundamental law of nature. It turns out that the hidden fundamental law is well forgotten old one directly related to the Landau---Migdal quasiparticles, while the basic properties and the scaling behavior of the strongly correlated systems can be described within the framework of the fermion condensation quantum phase transition (FCQPT). The phase transition comprises the extended quasiparticle paradigm that allows us to explain the non-Fermi liquid (NFL) behavior observed in these systems. In contrast to the Landau paradigm stating that the quasiparticle effective mass is a constant, the effective mass of new quasiparticles strongly depends on temperature, magnetic field, pressure, and other parameters. Our observations are in good agreement with experimental facts and show that FCQPT is responsible for the observed NFL behavior and quasiparticles survive both high temperatures and high magnetic fields.Comment: 17 pages, 17 figures. Dedicated to 100th anniversary of A.B.Migdal birthda

    Improved Measurement of the Partial-Rate CP Asymmetry in B+ -> K0pi+ and B- -> K0bar pi- Decays

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    We report an improved measurement of the partial-rate CP asymmetry in B+ => K0pi+ and B- => K0bar pi- decays. The analysis is based on a data sample of 85 million BBbar pairs collected at the Upsilon(4S) resonance with the Belle detector at the KEKB e+ e- storage ring. We measure Acp(K0pi+-) = 0.07^{+0.09 +0.01}_{-0.08 -0.03}, where the first and second errors are statistical and systematic, respectively; the corresponding 90% confidence-level interval is -0.10 < Acp(K0pi+-) < 0.22 .Comment: 7 pages, 8 figures, submitted to Phys. Rev.

    Measurement of Branching Fractions and Charge Asymmetries for Two-Body B Meson Decays with Charmonium

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    We report branching fractions and charge asymmetries for exclusive decays of charged and neutral B mesons to two-body final states containing a charmonium meson, J/psi or psi(2S). This result is based on a 29.4 fb^{-1} data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric e+e- collider.Comment: 13 pages, 5 figures, revte

    Mesurement of the B0 - anti-B0 Mixing Parameter Delta m_d using Semileptonic B0 Decays

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    We present a measurement of the B^0-B^0bar mixing parameter Delta m_d using neutral B meson pairs in a 29.1 fb^{-1} data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^+e^- collider. We exclusively reconstruct one neutral B meson in the semileptonic B^0 \to D^{*-}\ell^+\nu decay mode and identify the flavor of the accompanying B meson from its decay products. From the distribution of the time intervals between the two flavor-tagged B meson decay points, we obtain Delta m_d = (0.494 +- 0.012 +- 0.015) ps^{-1}, where the first error is statistical and the second error is systematic.Comment: 10 pages, 3 figures, Published in Phys.Rev.Lett. 89, 251803 (2002

    Study of B0ˉD()0π+π\bar{B^{0}} \to D^{(*)0} \pi^+ \pi^- Decays

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    We report on a study of B0ˉD()0π+π\bar{B^{0}} \to D^{(*) 0} \pi^+ \pi^- decays using 29.1 fb1^{-1} of e+ee^{+}e^{-} annihilation data recorded at the Υ(4S)\Upsilon(4S) resonance with the Belle detector at the KEKB storage ring. Making no assumptions about the intermediate mechanism, the branching fractions for Bˉ0D0π+π\bar{B}^0 \to D^0 \pi^+ \pi^- and Bˉ0D0π+π\bar{B}^0 \to D^{* 0} \pi^+ \pi^- are determined to be (8.0±0.6±1.5)×104(8.0 \pm 0.6 \pm 1.5) \times 10^{-4} and (6.2±1.2±1.8)×104 (6.2 \pm 1.2 \pm 1.8) \times 10^{-4} respectively. An analysis of B0ˉD0π+π\bar{B^{0}} \to D^{0} \pi^+ \pi^- candidates yields to the first observation of the color-suppressed hadronic decay Bˉ0D0ρ0\bar{B}^0 \to D^0 \rho^0 with the branching fraction (2.9±1.0±0.4)×104(2.9 \pm 1.0 \pm 0.4) \times 10^{-4}. We measure the ratio of branching fractions B(B0ˉD0ρ0)/B(B0ˉD0ω){\mathcal B}(\bar{B^0} \to D^0 \rho^0) / {\mathcal B}(\bar{B^0} \to D^0 \omega) = 1.6 ±\pm 0.8.Comment: 13 pages, LaTex, 4 figures, submitted to Phys. Lett.

    Charmless Hadronic Two-Body B Meson Decays

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    We report the results of a study of two-body B meson decays to the complete set of K pi, pi pi, and K K final states. The study is performed on a data sample of 31.7 +/- 0.3 million B B-bar events recorded on the Upsilon(4S) resonance by the Belle experiment at KEKB. We observe significant signals in all K pi final states and in the pi+ pi- and pi+ pi0 final states. We set limits on the pi0 pi0 and K K final states. A search is performed for partial-rate asymmetries between conjugate states for flavor-specific final states.Comment: Submitted to PR

    Measurement of the B0Bˉ0B^0 -\bar{B}^0 mixing rate with B0(Bˉ0)Dπ±B^0(\bar{B}^0) \to D^{*\mp} \pi^{\pm} partial reconstruction

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    We report a measurement of the B0Bˉ0B^0-\bar{B}^0 mixing parameter Δmd\Delta m_d based on a 29.1 fb1\rm 29.1~fb^{-1} sample of Υ(4S)\Upsilon (4S) resonance decays collected by the Belle detector at the KEKB asymmetric e+ee^+ e^- collider. We use events with a partially reconstructed B0(Bˉ0)Dπ±B^0(\bar{B}^0) \to D^{*\mp} \pi^{\pm} candidate and where the flavor of the accompanying BB meson is identified by the charge of the lepton from a B0(Bˉ0)X±νB^0(\bar{B}^0) \to X^{\mp} \ell^{\pm} \nu decay. The proper-time difference between the two BB mesons is determined from the distance between the two decay vertices. From a simultaneous fit to the proper-time distributions for the same-flavor (B0(Bˉ0)B^0(\bar{B}^0), ±\ell^{\pm}) and opposite-flavor (B0(Bˉ0)B^0(\bar{B}^0), \ell^{\mp}) event samples, we measure the mass difference between the two mass eigenstates of the neutral BB meson to be Δmd\Delta m_d= (0.509±0.017 (stat)±0.020 (syst)) ps1(0.509 \pm 0.017~(\rm stat) \pm 0.020~(\rm syst))~ps^{-1}.Comment: 16 pages, 14 figure

    Evidence for CP-Violating Asymmetries in B0->pi+pi- Decays and Constraints on the CKM Angle phi2

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    We present an improved measurement of CP-violating asymmetries in B0 -> pi+ pi- decays based on a 78 fb^-1 data sample collected at the Y(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e- collider. We reconstruct one neutral B meson as a B0 -> pi+ pi- CP eigenstate and identify the flavor of the accompanying B meson from inclusive properties of its decay products. We apply an unbinned maximum likelihood fit to the distribution of the time intervals between the two B meson decay points. The fit yields the CP-violating asymmetry amplitudes Apipi = +0.77+/-0.27(stat)+/-0.08(syst) and Spipi = -1.23+/-0.41(stat)+0.08/-0.07(syst), where the statistical uncertainties are determined from Monte Carlo pseudo-experiments. We obtain confidence intervals for CP-violating asymmetry parameters Apipi and Spipi based on a frequentist approach. We rule out the CP-conserving case, Apipi=Spipi=0, at the 99.93% confidence level. We discuss how these results constrain the value of the CKM angle phi2.Comment: 26 pages, 13 figures, submitted to Phys. Rev.
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