Ethological and experimental approaches to behavior analysis: implications for ecotoxicology.

Laboratory research in toxicology has progressed far beyond reliance on measures of mortality to make use of sophisticated behavioral preparations that can evaluate the consequences of sublethal toxicant exposure. In contrast, field studies have not evolved as rapidly. Approaches developed by experimental psychologists and ethologists provide powerful and complementary methodologies to the study of environmental pollutants and behavior. Observational data collection techniques can easily be used to broaden the number of questions addressed regarding sublethal exposure to toxic agents in both field and laboratory environments. This paper provides a background in such techniques, including construction of ethograms and observational methodologies, and the use of laboratory analogues to naturally occurring activities such as social behavior, predation, and foraging. Combining ethological and experimental approaches in behavior analysis can result in a more comprehensive evaluation of the effects of environmental contaminants on behavior

On the Red-Green-Blue Model

We experimentally study the red-green-blue model, which is a sytem of loops obtained by superimposing three dimer coverings on offset hexagonal lattices. We find that when the boundary conditions are ``flat'', the red-green-blue loops are closely related to SLE_4 and double-dimer loops, which are the loops formed by superimposing two dimer coverings of the cartesian lattice. But we also find that the red-green-blue loops are more tightly nested than the double-dimer loops. We also investigate the 2D minimum spanning tree, and find that it is not conformally invariant.Comment: 4 pages, 7 figure

Capital Offense: The SEC\u27s Continuing Failure to Address Small Business Financing Concerns

Despite years of criticism from small business advocates, the Securities and Exchange Commission has made little effort to ameliorate the severe burdens on small companies seeking to raise capital in compliance with the Securities Act of 1933 and SEC regulations. Substantial SEC attention has been given in recent years to improving the capacity of large, publicly-held companies to market securities, but smaller companies have suffered from less-than-benign neglect. Responding to this concern, the SEC recently adopted several proposals, and has others pending, aimed at small business financing. These proposals and adoptions, while modestly helpful, fall far short of addressing the capital formation problems caused principally by SEC regulation and interpretations. In this article, the authors examine the principal hurdles facing small businesses seeking to raise capital under the securities laws, analyze the background and potential bases for the current regulatory regime, offer a critique based upon the twin goals of protecting investors and providing meaningful financing opportunities for smaller businesses and set forth reform recommendations

Capital Offense: The SEC\u27s Continuing Failure to Address Small Business Financing Concerns

Despite years of criticism from small business advocates, the Securities and Exchange Commission has made little effort to ameliorate the severe burdens on small companies seeking to raise capital in compliance with the Securities Act of 1933 and SEC regulations. Substantial SEC attention has been given in recent years to improving the capacity of large, publicly-held companies to market securities, but smaller companies have suffered from less-than-benign neglect. Responding to this concern, the SEC recently adopted several proposals, and has others pending, aimed at small business financing. These proposals and adoptions, while modestly helpful, fall far short of addressing the capital formation problems caused principally by SEC regulation and interpretations. In this article, the authors examine the principal hurdles facing small businesses seeking to raise capital under the securities laws, analyze the background and potential bases for the current regulatory regime, offer a critique based upon the twin goals of protecting investors and providing meaningful financing opportunities for smaller businesses and set forth reform recommendations

Several new catalysts for reduction of oxygen in fuel cells

Test results prove nickel carbide or nitride, nickel-cobalt carbide, titanium carbide or nitride, and intermetallic compounds of the transition or noble metals to be efficient electrocatalysts for oxygen reduction in alkaline electrolytes in low temperature fuel cells

Acute complete heart block in dogs

A study has been conducted immediately and up to 18 days after the surgical production of complete heart block in dogs. Immediately after surgery cardiac output, coronary flow, and mean arterial pressure were reduced in rough proportion to the degree of bradycardia. In time, these measures began to return toward preoperative levels. Paralleling the diminished left ventricular work was a diminished left ventricular oxygen consumption with little consequent change in myocardial efficiency. Small rises were detected in central venous pressure. At autopsy, the only unequivocal abnormality was myocardial hypertrophy which became measurable between 2 and 18 days after operation

Local Statistics of Realizable Vertex Models

We study planar "vertex" models, which are probability measures on edge subsets of a planar graph, satisfying certain constraints at each vertex, examples including dimer model, and 1-2 model, which we will define. We express the local statistics of a large class of vertex models on a finite hexagonal lattice as a linear combination of the local statistics of dimers on the corresponding Fisher graph, with the help of a generalized holographic algorithm. Using an $n\times n$ torus to approximate the periodic infinite graph, we give an explicit integral formula for the free energy and local statistics for configurations of the vertex model on an infinite bi-periodic graph. As an example, we simulate the 1-2 model by the technique of Glauber dynamics

The Effects of Massive Substructures on Image Multiplicities in Gravitati onal Lenses

Surveys for gravitational lens systems have typically found a significantly larger fraction of lenses with four (or more) images than are predicted by standard ellipsoidal lens models (50% versus 25-30%). We show that including the effects of smaller satellite galaxies, with an abundance normalized by the observations, significantly increases the expected number of systems with more than two images and largely explains the discrepancy. The effect is dominated by satellites with ~20% the luminosity of the primary lens, in rough agreement with the typical luminosities of the observed satellites. We find that the lens systems with satellites cannot, however, be dropped from estimates of the cosmological model based on gravitational lens statistics without significantly biasing the results.Comment: 23 pages, 7 figures, more discussion of sis vs sie and inclusion of uncorrelated contribution

On Computational Complexity of Clifford Algebra

After a brief discussion of the computational complexity of Clifford algebras, we present a new basis for even Clifford algebra Cl(2m) that simplifies greatly the actual calculations and, without resorting to the conventional matrix isomorphism formulation, obtains the same complexity. In the last part we apply these results to the Clifford algebra formulation of the NP-complete problem of the maximum clique of a graph introduced in a previous paper.Comment: 13 page