Totally Umbilical Hypersurfaces in a Locally Symmetric Manifold

In this paper we obtain some formulas for totally umbilical hypersurfaces in a locally symmetric manifold, and derive some local results on the hypersurfaces from these formulas.     

The intertwining lifting theorem for ordered groups

Sz.-Nagy's dilation theorem for a contraction on a Hilbert space has been extended by Mlak to the case of a contraction semigroup whose indices are the positive elements of a totally ordered discrete group. We generalize to this case the intertwining lifting theorem of Sz.-Nagy and Foias. Some previous interpolation results on ordered groups are obtained as consequences.     

石墨炉原子吸收法测定钒的研究

本文比较了在标准石墨管,热解涂层和全热解石墨管中钒的吸收信号形状。用全热解石墨管和EDTA铵盐作基体改进剂,直接测定水系沉积物中痕量钒。方法的特征量为61pg/0.0044A。     

Pharmacokinetic detection of penicillin excreted in urine using a totally internally reflected resonance light scattering technique with cetyltrimethylammonium bromide

A quantitative analysis method for penicillins including ampicillin (AmP), benzyl penicillin (BP), oxacillin (OA) and amoxycillin (AmO) is proposed that makes use of the totally internally reflected resonance light scattering (TIR-RLS) signal from the penicillin at the H₂O/CCl₄ interface in the presence of cetyltrimethylammonium bromide (CTMAB), and enables the pharmacokinetics of penicillin taken orally and excreted through urine to be monitored. Penicillin is coadsorbed with CTMAB at the H₂O/CCl₄ interface in neutral solution, resulting in the formation of ion associates that display greatly enhanced TIR-RLS signals (maximum at 368–372 nm). This enhanced TIR-RLS intensity was found to be proportional to the penicillin concentration over the range 0.2×10^–6 to 2.2×10^–6 mol L^–1, with limits of determination (3) of 5.0×10^–8 to 7.0×10^–8 mol L^–1. Pharmacokinetics studies performed using the present method show that the excretion of orally-taken ampicillin through urine has a half-time of 1.05 h and an excremental quantum over 8 h of 49.3%, respectively.     

Codimension reduction in symmetric spaces

In this paper we give a short geometric proof of a generalization of a well-known result about reduction of codimension for submanifolds of Riemannian symmetric spaces.     

Universal conditions for algebraic travelling salesman problems to be efficiently solvable

We consider Travelling Salesman Problems (TSPs) where the cost of a tour is an algebraic composition of the cost coefficients that are elements of a totally ordered, commutative semigroup. Conditions for the cost matrix are stated which allow to solve these problems in polynomial time. In particular, we investigate conditions which guarantee that an optimal tour is pyramidal and can therefore be determined in O(n ²) time. Furthermore, we discuss TSP_s with Brownian as well as those with left-upper-triangular cost matrices.     

VARIATIONAL PROPERTIES OF THE INTEGRATED MEAN CURVATURES OF TUBES IN SYMMETRIC SPACES

61. IntroductionLet P be a submanifold of an n-dimensional riemannian manifold AI. Expressions fOrthe kth integrated mean curvatures, M^P(t), (i. e. the integral of tho kth mcan curvature,k = 0, 1,' l n -- l), of a tubular hypersurface P of radius t about P, in terms of theRiemann curvature tensor of P. are calculated when AI is Euclidean or a rank one symmetricspace[5'13"1. Moreover, when P is a closed convex hypersurface of thc n-dimensional spaceof constant curvature A', Santal6 has…