1,771 research outputs found
Coherent States, Dynamics and Semiclassical Limit on Quantum Groups
Coherent states on the quantum group are defined by using harmonic
analysis and representation theory of the algebra of functions on the quantum
group. Semiclassical limit is discussed and the crucial role
of special states on the quantum algebra in an investigation of the
semiclassical limit is emphasized. An approach to -deformation as a -Weyl
quantization and a relavence of contact geometry in this context is pointed
out. Dynamics on the quantum group parametrized by a real time variable and
corresponding to classical rotations is considered.Comment: 20 pages in latex, SFU-HEP-108-9
Revealing and Resolving the Restrained Enzymatic Cleavage of DNA Self-Assembled Monolayers on Gold: Electrochemical Quantitation and ESI-MS Confirmation
Herein we report a combined electrochemical and ESI-MS study of the enzymatic hydrolysis efficiency of DNA self-assembled monolayers (SAMs) on gold, platform systems for understanding nucleic acid surface chemistry and for constructing DNA-based biosensors. Our electrochemical approach is based on the comparison of the amounts of surface-tethered DNA nucleotides before and after Exonuclease I (Exo I) incubation using electrostatically bound [Ru(NH3)6]3+ as redox indicators. It is surprising to reveal that the hydrolysis efficiency of ssDNA SAMs does not depend on the packing density and base sequence, and that the cleavage ends with surface-bound shorter strands (9-13 mers). The ex-situ ESI-MS observations confirmed that the hydrolysis products for ssDNA SAMs (from 24 to 56 mers) are dominated with 10-15 mer fragments, in contrast to the complete digestion in solution. Such surface-restrained hydrolysis behavior is due to the steric hindrance of the underneath electrode to the Exo I/DNA binding, which is essential for the occurrence of Exo I-catalyzed processive cleavage. More importantly, we have shown that the hydrolysis efficiency of ssDNA SAMs can be remarkably improved by adopting long alkyl linkers (locating DNA strands further away from the substrates)
Correlation functions in the Coulomb branch of N=4 SYM from AdS/CFT correspondence
In the present paper we study SU(N)->S(U(N/2)xU(N/2)) symmetry breaking in
N=4 SYM via AdS/CFT correspondence. We consider two stacks of N/2 parallel D3
branes separated by a distance 2\vec d. In this case there is mixing between
the different l-wave dilatonic KK modes. We calculate certain the two point
correlation functions in the dual gauge theory. Due to mode mixing, the
diagonal correlation functions have 1/N conformal-like correction as well as
deformation terms. The off-diagonal correlators are also non-vanishing and
their leading order is 1/N. We discuss briefly the spectrum of the glueball
exitations.Comment: 25 pages, more comments on two throat geometry, decoupling limit and
correction terms, a few typos corrected, two references added; to appear in
Phys.Rev.
Patterns of Individual Shopping Behavior
Much of economic theory is built on observations of aggregate, rather than
individual, behavior. Here, we present novel findings on human shopping
patterns at the resolution of a single purchase. Our results suggest that much
of our seemingly elective activity is actually driven by simple routines. While
the interleaving of shopping events creates randomness at the small scale, on
the whole consumer behavior is largely predictable. We also examine
income-dependent differences in how people shop, and find that wealthy
individuals are more likely to bundle shopping trips. These results validate
previous work on mobility from cell phone data, while describing the
unpredictability of behavior at higher resolution.Comment: 4 pages, 5 figure
Generalized action principle and extrinsic geometry for N=1 superparticle
It is proposed the generalized action functional for N=1 superparticle in
D=3,4,6 and 10 space-time dimensions. The superfield geometric approach
equations describing superparticle motion in terms of extrinsic geometry of the
worldline superspace are obtained on the base of the generalized action. The
off-shell superdiffeomorphism invariance (in the rheonomic sense) of the
superparticle generalized action is proved. It was demonstrated that the half
of the fermionic and one bosonic (super)fields disappear from the generalized
action in the analytical basis. Superparticle interaction with Abelian gauge
theory is considered in the framework of this formulation. The geometric
approach equations describing superparticle motion in Abelian background are
obtained.Comment: 31 pages. Late
Adaptive Lévy processes and area-restricted search in human foraging
A considerable amount of research has claimed that animals’ foraging behaviors display movement lengths with power-law distributed tails, characteristic of Lévy flights and Lévy walks. Though these claims have recently come into question, the proposal that many animals forage using Lévy processes nonetheless remains. A Lévy process does not consider when or where resources are encountered, and samples movement lengths independently of past experience. However, Lévy processes too have come into question based on the observation that in patchy resource environments resource-sensitive foraging strategies, like area-restricted search, perform better than Lévy flights yet can still generate heavy-tailed distributions of movement lengths. To investigate these questions further, we tracked humans as they searched for hidden resources in an open-field virtual environment, with either patchy or dispersed resource distributions. Supporting previous research, for both conditions logarithmic binning methods were consistent with Lévy flights and rank-frequency methods–comparing alternative distributions using maximum likelihood methods–showed the strongest support for bounded power-law distributions (truncated Lévy flights). However, goodness-of-fit tests found that even bounded power-law distributions only accurately characterized movement behavior for 4 (out of 32) participants. Moreover, paths in the patchy environment (but not the dispersed environment) showed a transition to intensive search following resource encounters, characteristic of area-restricted search. Transferring paths between environments revealed that paths generated in the patchy environment were adapted to that environment. Our results suggest that though power-law distributions do not accurately reflect human search, Lévy processes may still describe movement in dispersed environments, but not in patchy environments–where search was area-restricted. Furthermore, our results indicate that search strategies cannot be inferred without knowing how organisms respond to resources–as both patched and dispersed conditions led to similar Lévy-like movement distributions
Chiral and herringbone symmetry breaking in water-surface monolayers
We report the observation from monolayers of eicosanoic acid in the L′2 phase of three distinct out-of-plane first-order diffraction peaks, indicating molecular tilt in a nonsymmetry direction and hence the absence of mirror symmetry. At lower pressures the molecules tilt in the direction of their nearest neighbors. In this region we find a structural transition, which we tentatively identify as the rotator-herringbone transition L2d−L2h
Truncated Levy Random Walks and Generalized Cauchy Processes
A continuous Markovian model for truncated Levy random walks is proposed. It
generalizes the approach developed previously by Lubashevsky et al. Phys. Rev.
E 79, 011110 (2009); 80, 031148 (2009), Eur. Phys. J. B 78, 207 (2010) allowing
for nonlinear friction in wondering particle motion and saturation of the noise
intensity depending on the particle velocity. Both the effects have own reason
to be considered and individually give rise to truncated Levy random walks as
shown in the paper. The nonlinear Langevin equation governing the particle
motion was solved numerically using an order 1.5 strong stochastic Runge-Kutta
method and the obtained numerical data were employed to calculate the geometric
mean of the particle displacement during a certain time interval and to
construct its distribution function. It is demonstrated that the time
dependence of the geometric mean comprises three fragments following one
another as the time scale increases that can be categorized as the ballistic
regime, the Levy type regime (superballistic, quasiballistic, or superdiffusive
one), and the standard motion of Brownian particles. For the intermediate Levy
type part the distribution of the particle displacement is found to be of the
generalized Cauchy form with cutoff. Besides, the properties of the random
walks at hand are shown to be determined mainly by a certain ratio of the
friction coefficient and the noise intensity rather then their characteristics
individually.Comment: 7 pages, 3 figure
p-Brane Solutions in Diverse Dimensions
A generic Lagrangian, in arbitrary spacetime dimension, describing the
interaction of a graviton, a dilaton and two antisymmetric tensors is
considered. An isotropic p-brane solution consisting of three blocks and
depending on four parameters in the Lagrangian and two arbitrary harmonic
functions is obtained. For specific values of parameters in the Lagrangian the
solution may be identified with previously known superstring solutions.Comment: 15 pages, latex, no figure
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