The Weyl character formula, the half-spin representations, and equal rank subgroups

Let B be a reductive Lie subalgebra of a semi-simple Lie algebra F of the same rank both over the complex numbers. To each finite dimensional irreducible representation Vlambda of F we assign a multiplet of irreducible representations of B with m elements in each multiplet, where m is the index of the Weyl group of B in the Weyl group of F. We obtain a generalization of the Weyl character formula; our formula gives the character of Vlambda as a quotient whose numerator is an alternating sum of the characters in the multiplet associated to Vlambda and whose denominator is an alternating sum of the characters of the multiplet associated to the trivial representation of F.

Isolation of Actinobacillus equuli from the oral cavity of healthy horses and comparison of isolates by restriction enzyme digestion and pulsed-field gel electrophoresis

Swab samples were collected from the oral cavity of 174 horses in 10 farms and cultured selectively for Actinobacillus equuli. A. equuli could be isolated from 37% of all samples, varying between 12 and 88% in the different farms. Eight horses were sampled repeatedly for several days, with a variation in isolation frequency between 50 and 88%. Isolates were compared by restriction enzyme digestion and Pulsed-Field Gel Electrophoresis. A high degree of strain variability was found within each horse population as well as some variability over time between strains isolated from the same horse.

Aeromonas hydrophila septicaemia in a grey seal (Halichoerus grypus) from the Baltic Sea: a case study

Aeromonas hydrophila septicaemia in a grey seal (Halichoerus grypus) from the Swedish part of the Baltic Sea is reported. The pathogen was isolated from both lung and spleen specimens. All of the A. hydrophila isolates produced haemolysin and Vero active cytotoxin. The aerolysin gene was found in all tested isolates as evidenced by the polymerase chain reaction (PCR) technique. Also, all isolates tested showed identical patterns of biochemical and antibiotic resistance. As Aeromonas spp. commonly occur in aquatic environments, we suggest that organisms from this genus may also play an important role as opportunistic pathogens in morbillivirus infected seals.

Biochemical modulation of tumor cell energy in vivo: II. A lower dose of adriamycin is required and a greater antitumor activity is induced when cellular energy is depressed

A quadruple drug combination--consisting of a triple-drug combination of N-(phosphonacetyl)-L-aspartate (PALA) + 6-methylmercaptopurine riboside (MMPR) + 6-amino-nicotinamide (6-AN), designed to primarily deplete cellular energy in tumor cells, + Adriamycin (Adria)--yielded significantly enhanced anticancer activity (i.e., tumor regressions) over that produced by either Adria alone at maximum tolerated dose (MTD) or by the triple-drug combination, against large, spontaneous, autochthonous murine breast tumors. The adenosine triphosphate (ATP)-depleting triple-drug combination administered prior to Adria resulted in a 100% tumor regression rate (12% complete regression; 88% partial regression) of spontaneous tumors. Histological examination of treated tumors demonstrated that the treatment-induced mechanism of cancer cell death was by apoptosis. The augmented therapeutic results (100% tumor regressions) were obtained with approximately one-half the MTD of Adria as a single agent and suggest the potential clinical benefit of longer, more effective, and safer treatment by low doses of Adria when combined with the triple-drug combination. Two likely mechanisms of action are discussed: (1) prevention of DNA repair; (2) complementary disruption of biochemical pathways by both the triple-drug combination and the biochemical cascade of apoptosis that is induced by a DNA-damaging anticancer agents such as Adria.

On the London equations

The classical London equations for superconductors are written in differential form notation and recast in relativistic form, where they yield the Proca equation. In particular, the field itself acts as its own charge carrier.

Superconnections and internal supersymmetry dynamics

In previous papers we proposed a theory of internal supersymmetry using the superalgebra su(n/1) to give rise to a unified structure that included quarks and leptons in 2n-5 generations. In the present paper we suggest that the notion of superconnections as introduced by Quillen provides a natural setting for the dynamics of an internally supersymmetric theory with the Higgs field occurring as the "zero-th order part" of the superconnection. The Higgs mechanism enters quadratically into the curvature of the superconnection and hence quartically into the Lagrangian. The supercovariant derivative gives a coupling of the Higgs field to the matter field similar to that put in "by hand" in the Lagrangian of the Weinberg-Salam theory.

Douglas' solution of the Plateau problem

Using ideas suggested by some recent developments in string theory, we give here an elementary demonstration of one of the key steps in Douglas' celebrated proof of the existence of solutions of the Plateau problem in n dimensions.

On the automorphism group of the conformal superalgebra

There is no automorphism of the conformal superalgebra that induces PT (parity and time reversal) on space time. Those conformal transformations that induce PT must change the sign of the odd brackets. In particular, in any implementation of conformal supersymmetry, CP can preserve but CPT must (at best) reverse the sign of the odd brackets (C, charge conjugation).

A monoclonal antibody which detects a 125 kd glycoprotein on embryonal carcinoma cells and is mitogenic for murine spleen cells

The isolation and characterisation of a monoclonal antibody (2H9), selected for reactivity against murine teratocarcinoma stem cells, is described. This antibody recognizes one major glycoprotein on the surface of embryonal carcinoma (EC) cells but detects multiple glycoprotein species on various murine or human derived cell types. The binding of the antibody to cells is abolished by treatment with periodate or neuraminidase. These results suggest that 2H9 antibody detects a carbohydrate determinant; this is apparently distinct from other anti-EC reactive monoclonal antibodies and a variety of lectins. These antibodies are mitogenic for a population of lymphocytes in murine spleen. The antibodies recognize numerous cell surface glycoproteins on the surface of the spleen cells.

Perception, production, and imitation of time ratios by skilled musicians

We have described our exploration of the judgment, production, and imitation of fractions of a beat by skilled musicians, illustrating our findings with data from violinist and conductor Paul Zukofsky. For small fractions we found systematic and substantial errors. In the judgment task small stimulus fractions are associated with names that are too large (overestimation). In both production and imitation tasks the fractions produced were too large (overproduction, overimitation). A summary of our findings and of the expectations they violate is provided in Figure 7. The temporal patterns we used are perhaps the simplest that qualify as rhythms, incorporating just a beat interval and a fraction. The phenomena we discovered in relation to these simple patterns, and their implications for underlying mechanisms, must be considered in attempts to understand the perception and production of more complex rhythms, as in actual music. We explored and rejected several plausible explanations for the overestimation and overproduction of small fractions. Although we have as yet no satisfactory explanations of the errors themselves, relations among the errors have powerful implications for human timing mechanisms. The relation between the errors in judgment and production requires us to reject a feedback model of production, in which a subject uses the same processes as in the judgment task to evaluate and adjust his performance in the production task. An explanation of the inconsistency between judgment and production seems most likely to lie in a change in time perception induced by the production task. Together with the existence of systematic errors in judgment, the equality of the errors in production and imitation argues that imitation is not accomplished by concatenating all the processes used in judgment and production. Our results are instead consistent with a model containing four internal transformation processes, in which judgment and production share no process, but do involve the same internal-fraction representation, and in which imitation shares one process with judgment and another with production.

Internal supersymmetry and unification

We construct a family of finite-dimensional representations of the superalgebra sl(n/m) that depend on an integer parameter for m > 1 and on a complex parameter, b, for m = 1. We describe some models of elementary particles for sl(2/1), sl(3/1), and sl(5/1). This involves the choice of the parameter b and the choice of the operators I(3) (the third component of the weak left-handed isospin) and U (the weak hypercharge). These must commute, and are related to the electric charge by the usual formula Q = I(3) + (1/2)U. In particular, taking I(3) to be in its standard form in su(2) subset sl(5) subset sl(5/1) and requiring that U commute with color su(3) subset sl(5) subset sl(5/1) leaves three free parameters, two for the choice of U and one for the choice of b. We show that there are just two possible choices of these parameters yielding exactly all 32 quark and lepton charges: the Georgi-Glashow U in su(5), corresponding to U(1,-(2/3)) and arbitrary b and U(0,(1/3)) negated set membership su(5), with b = 2. We provide a general construction of representations of sl(n/1) consisting exactly of sequences of generations of quarks and leptons.