Search results for "outer"

Divisible Designs Admitting, as an Automorphism Group, an Orthogonal Group or a Unitary Group

2001

We construct some divisible designs starting from a projective space. These divisible designs admit an orthogonal group or a unitary group as an automorphism group.

Injective Fitting sets in automorphism groups

1993

Hausdorff measures, Hölder continuous maps and self-similar fractals

1993

Let f: A → ℝn be Hölder continuous with exponent α, 0 < α ≼ 1, where A ⊂ ℝm has finite m-dimensional Lebesgue measure. Then, as is easy to see and well-known, the s-dimensional Hausdorif measure HS(fA) is finite for s = m/α. Many fractal-type sets fA also have positive Hs measure. This is so for example if m = 1 and f is a natural parametrization of the Koch snow flake curve in ℝ2. Then s = log 4/log 3 and α = log 3/log 4. In this paper we study the question of what s-dimensional sets in can intersect some image fA in a set of positive Hs measure where A ⊂ ℝm and f: A → ℝn is (m/s)-Hölder continuous. In Theorem 3·3 we give a general density result for such Holder surfacesfA which implies…

On permutations of class sums of alternating groups

1997

We prove a result concerning the class sums of the alternating group An; as a consequence we deduce that if θ is a normalized automorphism of the integral group ring then there exists such that is the identity on , where Sn:is the symmetric group and is the center of

Some Hadamard designs with parameters (71,35,17)

2002

Up to isomorphisms there are precisely eight symmetric designs with parameters (71, 35, 17) admitting a faithful action of a Frobenius group of order 21 in such a way that an element of order 3 fixes precisely 11 points. Five of these designs have 84 and three have 420 as the order of the full automorphism group G. If |G| = 420, then the structure of G is unique and we have G = (Frob21 × Z5):Z4. In this case Z(G) = 〈1〉, G′ has order 35, and G induces an automorphism group of order 6 of Z7. If |G| = 84, then Z(G) is of order 2, and in precisely one case a Sylow 2-subgroup is elementary abelian. © 2002 Wiley Periodicals, Inc. J Combin Designs 10: 144–149, 2002; DOI 10.1002/jcd.996

Supercontinuum generation with 532 nm quasi-continuum pulses in photonic crystal fibre tapers

2007

We report experimental results on supercontinuum generation in PCF tapers using quasi-continuous pump pulses of 7 ns duration at 532 nm. SC generation in normal and anomalous dispersion regimes are presented. Introduction Supercontinuum generation (SC) in photonic crystal fibres (PCF), fibre tapers, and PCF tapers has been demonstrated in the past with pump pulses of fs, ps, and tenths of ns duration [1-2]. Here, we present experimental results on SC generation in PCF tapers using quasi-continuous pump pulses of 7 ns duration at 532 nm. Fabrication of the PCF tapers The PCF from which the tapers were made, was a large-air-hole PCF ("cobweb" PCF) with two rings of air holes around a solid si…

Endpoint Admission Control over Assured Forwarding PHBs and Its Performance over RED Implementations

2001

The Assured Forwarding Per Hop Behavior (AF PHB) has been devised by the IETF Differentiated Services (DiffServ) working group to provide drop level differentiation. The intent of AF is to support services with different loss requirements, but with no strict delay and jitter guarantees. Another suggested use of AF is to provide differentiated support for traffic conforming to an edge conditioning/policing scheme with respect to nonconforming traffic. Scope of this paper is twofold. First, we show that, quite surprisingly, a standard AF PHB class is semantically capable of supporting per flow admission control. This is obtained by adopting the AF PHB as core routers forwarding mechanism in c…

PCP: An End-to end Measurement Based Call Admission Control for Real-Time Services Over IP Networks

2000

Distributed end-to-end measurement based connection admission control mechanisms have been recently proposed. The goal of these schemes is to provide tight QoScon trol on a per connection basis by means of measurements taken by the edge nodes and priority based forwarding procedure at internal nodes. Since the additional flows handling procedures are implemented at the border routers and the forwarding mechanisms are for flows aggregates only, the approach is fully scalable and compatible with the IETF Differentiated Service proposal. The aim of this paper is to propose specific schemes and to investigate the advantages and limits of the approach by analyzing the basic mechanisms and evalua…

From subatomic to immense: About the possible influence of the Theory of Relativity and Quantum Mechanics in the fantastic

2015

The fantastic is based on three pillars: reality, the impossible and fear. Theoretical physics is a branch of science that has deeply studied reality, from the subatomic world to the immensity of outer space. In this article, we want to study how the Theory of Relativity and the Quantum Mechanics have influenced the configuration of the fantastic, and in addition, we want to verify if these branches of physics are capable of explaining certain fantastic phenomena.

The long-term cytoskeletal rearrangement induced by rabbit enteropathogenic Escherichia coli is Esp dependent but intimin independent.

1999

Attaching and effacing rabbit enteropathogenic Escherichia coli (REPEC) of the O103 serogroup adhere diffusely on HeLa cells and trigger a slow progressive cytopathic effect (CPE) characterized by the recruitment of vinculin and the assembly of actin stress fibres. In contrast to REPEC O103, the reference human EPEC strain E2348/69 is unable to trigger the CPE. In this study, we have shown first that the fimbrial adhesin AF/R2, which mediates the diffuse adhesion of REPEC O103, was not sufficient to induce the CPE capability upon E2348/69. Non-polar mutants of REPEC O103 for espA, espB, espD and eae were then constructed. The four mutants were unable to induce attaching and effacing lesions…