265 research outputs found
THE ROLE OF DENTISTRY IN FEDERAL-STATE-LOCAL COMPREHENSIVE HEALTH PLANNING *
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65702/1/j.1752-7325.1968.tb01419.x.pd
Quantum Pump for Fractional Charge
We propose a theoretical scenario for pumping of fractionally charged
quasi-particle in the context of fractional quantum Hall liquid. We
consider quasi-particle pumping across an anti-dot level tuned close to the
resonance. Fractional charge pumping is achieved by slow and periodic
modulation of coupling of the anti-dot level to left and right moving edges of
a Hall bar set-up. This is attained by periodically modulating the gate
voltages controlling the couplings. In order to obtain quantization of pumped
charge in the unit of the electronic charge fraction () per pumping
cycle in the adiabatic limit, we argue that the only possibility is to tune the
quasi-particle operator to be irrelevant from being relevant in the
renormalization group sense, which can be accomplished by invoking quantum Hall
line junctions into the Hall bar geometry. We also comment on possibility for
experimental realization of the above scenario.Comment: Version to appear in Europhys. Lett. (2008
Positive Magneto-Resistance in Quasi-1D Conductors
We present here a simple qualitative model that interpolates between the high
and low temperature properties of quasi-1D conductors. At high temperatures we
argue that transport is governed by inelastic scattering whereas at low
temperatures the conductance decays exponentially with the electron dephasing
length. The crossover between these regimes occurs at the temperature at which
the elastic and inelastic scattering times become equal. This model is shown to
be in quantitative agreement with the organic conductor .
Within this model, we also show that on the insulating side, the positive
magnetoresistance of the form observed in and
other quasi-1D conductors can be explained by the role spin-flip scattering
plays in the electron dephasing rate.Comment: 4 pages, Latex, no figure
Measurement of inclusive D*+- and associated dijet cross sections in photoproduction at HERA
Inclusive photoproduction of D*+- mesons has been measured for photon-proton
centre-of-mass energies in the range 130 < W < 280 GeV and a photon virtuality
Q^2 < 1 GeV^2. The data sample used corresponds to an integrated luminosity of
37 pb^-1. Total and differential cross sections as functions of the D*
transverse momentum and pseudorapidity are presented in restricted kinematical
regions and the data are compared with next-to-leading order (NLO) perturbative
QCD calculations using the "massive charm" and "massless charm" schemes. The
measured cross sections are generally above the NLO calculations, in particular
in the forward (proton) direction. The large data sample also allows the study
of dijet production associated with charm. A significant resolved as well as a
direct photon component contribute to the cross section. Leading order QCD
Monte Carlo calculations indicate that the resolved contribution arises from a
significant charm component in the photon. A massive charm NLO parton level
calculation yields lower cross sections compared to the measured results in a
kinematic region where the resolved photon contribution is significant.Comment: 32 pages including 6 figure
Measurement of Jet Shapes in Photoproduction at HERA
The shape of jets produced in quasi-real photon-proton collisions at
centre-of-mass energies in the range GeV has been measured using the
hadronic energy flow. The measurement was done with the ZEUS detector at HERA.
Jets are identified using a cone algorithm in the plane with a
cone radius of one unit. Measured jet shapes both in inclusive jet and dijet
production with transverse energies GeV are presented. The jet
shape broadens as the jet pseudorapidity () increases and narrows
as increases. In dijet photoproduction, the jet shapes have been
measured separately for samples dominated by resolved and by direct processes.
Leading-logarithm parton-shower Monte Carlo calculations of resolved and direct
processes describe well the measured jet shapes except for the inclusive
production of jets with high and low . The observed
broadening of the jet shape as increases is consistent with the
predicted increase in the fraction of final state gluon jets.Comment: 29 pages including 9 figure
Side jump contribution to spin-orbit mediated Hall effects and Berry curvature
Anomalous Hall effect and spin Hall effect originate due to spin-orbit
coupling that in the Kohn-Luttinger formalism is
represented by anomalous terms in the coordinate and velocity operators.
Relation of these operators to the Berry curvature in the momentum space is
presented for electrons in GaAs type semiconductors. For centrosymmetric
semiconductors, transformational properties of Berry curvature are discussed.Comment: 4 pages. Accepted for a special issue of Fiz. Tech. Semicond.
(Semiconductors, StPetersburg) dedicated to Vladimir I. Pere
Angular and Current-Target Correlations in Deep Inelastic Scattering at HERA
Correlations between charged particles in deep inelastic ep scattering have
been studied in the Breit frame with the ZEUS detector at HERA using an
integrated luminosity of 6.4 pb-1. Short-range correlations are analysed in
terms of the angular separation between current-region particles within a cone
centred around the virtual photon axis. Long-range correlations between the
current and target regions have also been measured. The data support
predictions for the scaling behaviour of the angular correlations at high Q2
and for anti-correlations between the current and target regions over a large
range in Q2 and in the Bjorken scaling variable x. Analytic QCD calculations
and Monte Carlo models correctly describe the trends of the data at high Q2,
but show quantitative discrepancies. The data show differences between the
correlations in deep inelastic scattering and e+e- annihilation.Comment: 26 pages including 10 figures (submitted to Eur. J. Phys. C
Chemistry and Biology of DNA Containing 1,N2-Deoxyguanosine Adducts of the α,β-Unsaturated Aldehydes Acrolein, Crotonaldehyde, and 4-Hydroxynonenal
Ingestion of oxygenated water enhances lactate clearance kinetics in trained runners
Abstract Background Drinks with higher dissolved oxygen concentrations have in recent times gained popularity as a potential ergogenic aid, despite a lack of evidence regarding their efficacy. The aim of this study was to assess effects of ingestion of an oxygen supplement (OS) on exercise performance and post-exercise recovery in a group of trained runners. Methods Trained male runners (n = 25, mean ± SD; age 23 ± 6 years, mass 70 ± 9 kg, BMI 21.9 ± 2.7 kg.m−2 VO2max 64 ± 6mL.kg−1.min−1), completed a randomised double blinded, crossover study to assess the effect of ingestion of OS solution on exercise performance and recovery. Trials consisted of a 30min rest period, 5min warm-up, a 5000m treadmill time-trial, and a 30min passive recovery. Participants ingested 6x15mL of either OS or a taste matched placebo during the trials (3 during the rest phase, 1 during exercise and 2 during the recovery). Muscle tissue O2 saturation was measured via near infrared spectroscopy. Blood lactate concentrations were measured prior to, mid-way and directly after the finish of the 5000m time trials and every 3-min during the post-exercise recovery. Results Ingestion of OS did not improve exercise performance. No significant differences were observed for muscle tissue O2 saturation at any time-points. However, lactate clearance was significantly improved during recovery in the OS trials. Both AUC (109 ± 32 vs. 123 ± 38 mmol.min, P < 0.05, d = 0.40) and lactate half-life (λ) (1127 ± 272 vs. 1223 ± 334 s, P < 0.05, d = 0.32) were significantly reduced. Conclusions Despite no evidence of improved exercise performance, ingestion of OS did enhance post-exercise recovery via increased lactate clearance
Measurement of the F2 structure function in deep inelastic ep scattering using 1994 data from the ZEUS detector at HERA
We present measurements of the structure function \Ft\ in e^+p scattering at HERA in the range 3.5\;\Gevsq < \qsd < 5000\;\Gevsq. A new reconstruction method has allowed a significant improvement in the resolution of the kinematic variables and an extension of the kinematic region covered by the experiment. At \qsd < 35 \;\Gevsq the range in x now spans 6.3\cdot 10^{-5} < x < 0.08 providing overlap with measurements from fixed target experiments. At values of Q^2 above 1000 GeV^2 the x range extends to 0.5. Systematic errors below 5\perc\ have been achieved for most of the kinematic urray, W
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