173,615 research outputs found
New identities involving q-Euler polynomials of higher order
In this paper we give new identities involving q-Euler polynomials of higher
order.Comment: 11 page
Sound Scattering and Its Reduction by a Janus Sphere Type
Copyright © 2014 Delyia Kim et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Sound scattering by a Janus sphere type is considered. The sphere has two surface zones: a soft surface of zero acoustic impedance and a hard surface of infinite acoustic impedance. The zones are arranged such that axisymmetry of the sound field is preserved. The equivalent source method is used to compute the sound field. It is shown that, by varying the sizes of the soft and hard zones on the sphere, a significant reduction can be achieved in the scattered acoustic power and upstream directivity when the sphere is near a free surface and its soft zone faces the incoming wave and vice versa for a hard ground. In both cases the size of the sphere’s hard zone is much larger than that of its soft zone. The boundary location between the two zones coincides with the location of a zero pressure line of the incoming standing sound wave, thus masking the sphere within the sound field reflected by the free surface or the hard ground. The reduction in the scattered acoustic power diminishes when the sphere is placed in free space. Variations of the scattered acoustic power and directivity with the sound frequency are also given and discusse
Central Higgs Production at LHC from Single-Pomeron-Exchange
Contrary to common perceptions about systems produced in
Single-Pomeron-Exchange (SPE) pp interactions, the hard diffractive process
discovered at the CERN SPS-Collider leads to dominant central production of
Higgs bosons at the LHC. The rate for SPE production of Higgs bosons is
calculated to be 7-9 % of the total inclusive Higgs rate. In addition, an SPE
measurement program of dijet events is outlined for the early days of LHC
running which should answer many fundamental questions about the Pomeron
structure and its effective flux factor in the proton.Comment: 14 pages, 7 Encapsulated Postscript figures, LaTex, submitted to
European Phisical Journal
Universality Class of One-Dimensional Directed Sandpile Models
A general n-state directed `sandpile' model is introduced. The stationary
properties of the n-state model are derived for n < infty, and analytical
arguments based on a central limit theorem show that the model belongs to the
universality class of the totally asymmetric Oslo model, with a crossover to
uncorrelated branching process behavior for small system sizes. Hence, the
central limit theorem allows us to identify the existence of a large
universality class of one-dimensional directed sandpile models.Comment: 4 pages, 2 figure
Strategies to augment volitional and reflex function may improve locomotor capacity following incomplete spinal cord injury
Many studies highlight the remarkable plasticity demonstrated by spinal circuits following an incomplete spinal cord injury (SCI). Such plasticity can contribute to improvements in volitional motor recovery, such as walking function, although similar mechanisms underlying this recovery may also contribute to the manifestation of exaggerated responses to afferent input, or spastic behaviors. Rehabilitation interventions directed toward augmenting spinal excitability have shown some initial success in improving locomotor function. However, the potential effects of these strategies on involuntary motor behaviors may be of concern. In this article, we provide a brief review of the mechanisms underlying recovery of volitional function and exaggerated reflexes, and the potential overlap between these changes. We then highlight findings from studies that explore changes in spinal excitability during volitional movement in controlled conditions, as well as altered kinematic and behavioral performance during functional tasks. The initial focus will be directed toward recovery of reflex and volitional behaviors following incomplete SCI, followed by recent work elucidating neurophysiological mechanisms underlying patterns of static and dynamic muscle activation following chronic incomplete SCI during primarily single-joint movements. We will then transition to studies of locomotor function and the role of altered spinal integration following incomplete SCI, including enhanced excitability of specific spinal circuits with physical and pharmacological interventions that can modulate locomotor output. The effects of previous and newly developed strategies will need to focus on changes in both volitional function and involuntary spastic reflexes for the successful translation of effective therapies to the clinical setting
Modification of Decay Constants of Superstring Axions: Effects of Flux Compactification and Axion Mixing
We study possibilities for lowering the decay constants of superstring
axions. In the heterotic Calabi-Yau compactification, a localized
model-dependent axion can appear at a nearly collapsing 2-cycle. The effect of
flux can be used for generating warp factor suppression of the axion decay
constant. We also point out that the hidden sector instanton potential much
higher than the QCD instanton potential picks up the larger effective axion
decay constant as that of the QCD axion. We show that this can be converted by
introducing many hidden-sector quarks so that the decay constant of the QCD
axion turns out to be much smaller than the string scale.Comment: 6 pages with 3 figures, revtex; figure added,section of axion mixing
modifie
A note on q-Euler numbers and polynomials
The purpose of this paper is to construct q-Euler numbers and polynomials by
using p-adic q-integral equations on Zp. Finally, we will give some interesting
formulae related to these q-Euler numbers and polynomials.Comment: 6 page
Prediction of vertical bearing capacity of waveform micropile
This study proposes a predictive equation for bearing capacity considering the behaviour characteristics of a waveform micropile that can enhance the bearing capacity of a conventional micropile. The bearing capacity of the waveform micropile was analysed by a three-dimensional numerical model with soil and pile conditions obtained from the field and centrifuge tests. The load-transfer mechanism of the waveform micropile was revealed by the numerical analyses, and a new predictive equation for the bearing capacity was proposed. The bearing capacities of the waveform micropile calculated by the new equation were comparable with those measured from the field and centrifuge tests. This validated a prediction potential of the new equation for bearing capacity of waveform micropiles
A note on q-Bernoulli numbers and polynomials
By using p-adic q-integrals, we study the q-Bernoulli numbers and polynomials
of higher order.Comment: 8 page
Observation of non-classical rotational inertia in bulk solid 4He
In recent torsional oscillator experiments by Kim and Chan (KC), a decrease
of rotational inertia has been observed in solid 4He in porous materials and in
a bulk annular channel. This observation strongly suggests the existence of
"non-classical rotational inertia" (NCRI), i.e. superflow, in solid 4He. In
order to study such a possible "supersolid" phase, we perform torsional
oscillator experiments for cylindrical solid 4He samples. We have observed
decreases of rotational inertia below 200 mK for two solid samples (pressures P
= 4.1 and 3.0 MPa). The observed NCRI fraction at 70 mK is 0.14 %, which is
about 1/3 of the fraction observed in the annulus by KC. Our observation is the
first experimental confirmation of the possible supersolid finding by KC.Comment: 6 pages, 3 firures, submitted to J. Low Temp. Phys. (Proceedings of
QFS2006
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