18,141 research outputs found
Triangle in a brick
In this paper we shall investigate the following problem: Which is the
largest regular triangle in a brick with volume 1 and having edge lengthes
greater than ? We prove that there are three optimal cases
in all which the edge lengthes of the triangles are , respectively.Comment: 6 pages, 4 figure
Cosmological Brightness Distribution Fits of Gamma Ray Burst Sources
We discuss detailed fits of the BATSE and PVO gamma-ray burst peak-flux
distributions with Friedman models taking into account possible density
evolution and standard candle or power law luminosity functions. A chi-square
analysis is used to estimate the goodness of the fits and we derive the
significance level of limits on the density evolution and luminosity function
parameters. Cosmological models provide a good fit over a range of parameter
space which is physically reasonable.Comment: Ap.J. in press, uuencoded .ps file, 9 pages manuscript plus 5 figure
On the probability of hitting the boundary for Brownian motions on the SABR plane
Starting from the hyperbolic Brownian motion as a time-changed Brownian motion, we explore a set of probabilistic modelsârelated to the SABR model in mathematical financeâwhich can be obtained by geometry-preserving transformations, and show how to translate the properties of the hyperbolic Brownian motion (density, probability mass, drift) to each particular model. Our main result is an explicit expression for the probability of any of these models hitting the boundary of their domains, the proof of which relies on the properties of the aforementioned transformations as well as time-change methods
Strings in plane-fronted gravitational waves
Brinkmann's plane-fronted gravitational waves with parallel rays --~shortly
pp-waves~-- are shown to provide, under suitable conditions, exact string vacua
at all orders of the sigma-model perturbation expansion.Comment: 7 pages, no figure
Polyethylene imine-based receptor immobilization for label free bioassays
Polyethylene imine (PEI) based immobilization of antibodies is described and the concept is proved on the
label free assay of C-Reactive Protein (CRP). This novel immobilization method is composed of a hyperbranched
PEI layer which was deposited at a high pH (9.5) on the sensor surface. The free amino groups
of PEI were derivatized with neutravidin by Biotin N-hydroxysuccinimide ester and the biotinylated
anti-CRP antibody immobilized on this layer. Direct binding assay of recombinant CRP was successfully
performed in the low ÎŒg/ml concentrations using a label free optical waveguide biosensor
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