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121.
Romain Tessera 《Geometriae Dedicata》2008,136(1):203-220
We introduce a quantitative version of Property A in order to estimate the L
p
-compressions of a metric measure space X. We obtain various estimates for spaces with sub-exponential volume growth. This quantitative property A also appears to
be useful to yield upper bounds on the L
p
-distortion of finite metric spaces. Namely, we obtain new optimal results for finite subsets of homogeneous Riemannian manifolds.
We also introduce a general form of Poincaré inequalities that provide constraints on compressions, and lower bounds on distortion.
These inequalities are used to prove the optimality of some of our results.
相似文献
122.
123.
In this study, a new, sensitive, and rapid assay was developed to quantitatively measure the proteolytic enzyme activity using the surface-enhanced Raman scattering (SERS) probe. Two different shapes of gold nanoparticles, gold nanosphere and nanorod particles were produced. SERS label, comprising self-assembled monolayers (SAMs) of Raman reporter molecule (5,5-Dithiobis (2-Nitrobenzoic acid), DTNB), was coated on the surface of the nanoparticles. Two different SERS-based analysis platforms were designed using gold-coated glass slide and polystyrene microtiter plate. The calibration curves were obtained by plotting the intensity of the SERS signal of symmetric NO2 stretching of DTNB at 1326 cm−1vs. the protease concentration. The effects of nanoparticle geometry and assay platform on the protease assay were investigated and the best working combination of the parameters was selected as rod shaped SERS probe and gold-coated glass slide. The correlation between the protease activity and SERS signal was found to be linear within the range of 0.1-2 mU/mL (R2 = 0.979). The limit of detection (LOD) and limit of quantification (LOQ) values of the validated method were found as 0.43 and 1.30 mU/mL, respectively. The intra-day and inter-day precisions of the method, as relative standard deviation (RSD), were determined as 2.5% and 3.6%, respectively. The developed method was successfully applied for quantitative analysis of the commercial enzyme preparate that is used in cheese making process. It was also used for investigation of substrate specificity of protease enzyme towards the casein and bovine serum albumin. The proposed method has a flexibility to try different substrates for the detection of various enzyme activities. 相似文献
124.
We examine Hamiltonian formalism on Euclidean Snyder space. The latter corresponds to a lattice in the quantum theory. For any given dynamical system, it may not be possible to identify time with a real number parametrizing the evolution in the quantum theory. The alternative requires the introduction of a dynamical time operator. We obtain the dynamical time operator for the relativistic (nonrelativistic) particle, and use it to construct the generators of Poincaré (Galilei) group on Snyder space. 相似文献
125.
126.
127.
Biagio Ricceri 《Journal of Mathematical Analysis and Applications》2006,324(2):1282-1287
Given a bounded domain Ω⊂Rn, we prove that if is a C1 function whose gradient is Lipschitzian in Rn+1 and non-zero at 0, then, for each r>0 small enough, the restriction of the integral functional to the sphere has a unique global minimum and a unique global maximum. 相似文献
128.
R. Friedberg 《Annals of Physics》2010,325(2):345-275
A new formula has been given recently by A.A. Svidzinsky and M.O. Scully to describe the temporal evolution of the excitation function in a large sphere satisfying the Markov condition after excitation by a single photon. This formula is based on a physically reasonable Ansatz from which differential equations are inferred for the undetermined radial functions in the Ansatz. The solution to these differential equations leads to the formula for β. Numerical calculations from this formula yield a value ∼10% for the maximum probability of occupancy of secondary excited states.In this paper, we refine the formula of Svidzinsky and Scully by allowing the radial functions in the Ansatz to depend on the angular index l of the spherical Bessel functions. By using the Debye formula for the asymptotic behavior of jl(u) for large l as well as u, we obtain differential equations in each angular sector, similar to theirs but with a dependence on l. The solution to these equations yields our improved formula, from which we calculate 17.1% for the maximum probability of secondary excited states. 相似文献
129.
David Glickenstein 《Topology》2005,44(4):791-808
A combinatorial version of Yamabe flow is presented based on Euclidean triangulations coming from sphere packings. The evolution of curvature is then derived and shown to satisfy a heat equation. The Laplacian in the heat equation is shown to be a geometric analogue of the Laplacian of Riemannian geometry, although the maximum principle need not hold. It is then shown that if the flow is nonsingular, the flow converges to a constant curvature metric. 相似文献
130.
Yuan Xu 《Constructive Approximation》2005,22(1):67-93
For a weighted L1 space on the unit sphere of Rd+1, in which the
weight functions are invariant under finite reflection groups, a maximal
function is introduced and used to prove the almost everywhere convergence
of orthogonal expansions in h-harmonics. The result applies to various
methods of summability, including the de La Vallée Poussin means and the
Cesàro means. Similar results are also established for weighted orthogonal
expansions on the unit ball and on the simplex of Rd. 相似文献