Synopsis of biological data on the pink shrimp, Pandalus borealis Kroyer, 1838

This synopsis of the literature was designed to summarize the biological and biochemical studies involving Pandalus borealis as well as to provide a summary of the literature regarding the fisheries data published before early 1984. Included are many unpublished observations, drawn from studies at the State of Maine Department of Marine Resources Laboratory in West Boothbay Harbor, Maine. (PDF file contains 63 pages.

Lattice gas description of pyrochlore and checkerboard antiferromagnets in a strong magnetic field

Quantum Heisenberg antiferromagnets on pyrochlore and checkerboard lattices in a strong external magnetic field are mapped onto hard-core lattice gases with an extended exclusion region. The effective models are studied by the exchange Monte Carlo simulations and by the transfer matrix method. The transition point and the critical exponents are obtained numerically for a square-lattice gas of particles with the second-neighbor exclusion, which describes a checkerboard antiferromagnet. The exact structure of the magnon crystal state is determined for a pyrochlore antiferromagnet.Comment: 11 pages, accepted versio

A K-Theoretic Proof of Boutet de Monvel's Index Theorem for Boundary Value Problems

We study the C*-closure A of the algebra of all operators of order and class zero in Boutet de Monvel's calculus on a compact connected manifold X with non-empty boundary. We find short exact sequences in K-theory 0->K_i(C(X))->K_i(A/K)->K_{1-i}(C_0(T*X'))->0, i= 0,1, which split, where K denotes the compact ideal and T*X' the cotangent bundle of the interior of X. Using only simple K-theoretic arguments and the Atiyah-Singer Index Theorem, we show that the Fredholm index of an elliptic element in A is given as the composition of the topological index with mapping K_1(A/K)->K_0(C_0(T*X')) defined above. This relation was first established by Boutet de Monvel by different methods.Comment: Title slightly changed. Accepted for publication in Journal fuer die reine und angewandte Mathemati

Internal Energy of the Potts model on the Triangular Lattice with Two- and Three-body Interactions

We calculate the internal energy of the Potts model on the triangular lattice with two- and three-body interactions at the transition point satisfying certain conditions for coupling constants. The method is a duality transformation. Therefore we have to make assumptions on uniqueness of the transition point and that the transition is of second order. These assumptions have been verified to hold by numerical simulations for q=2, 3 and 4, and our results for the internal energy are expected to be exact in these cases.Comment: 9 pages, 4 figure

Energy and Structure of Hard-Sphere Bose Gases in three and two dimensions

The energy and structure of dilute gases of hard spheres in three dimensions is discussed, together with some aspects of the corresponding 2D systems. A variational approach in the framework of the Hypernetted Chain Equations (HNC) is used starting from a Jastrow wavefunction that is optimized to produce the best two--body correlation factor with the appropriate long range. Relevant quantities describing static properties of the system are studied as a function of the gas parameter $x=\rho a^d$ where $\rho$, $a$ and $d$ are the density, $s$--wave scattering length of the potential and dimensionality of the space, respectively. The occurrence of a maximum in the radial distribution function and in the momentum distribution is a natural effect of the correlations when $x$ increases. Some aspects of the asymptotic behavior of the functions characterizing the structure of the systems are also investigated.Comment: Proceedings of the QFS2004 conference in Trento. To appear in JLT

Measurement of Protein in Nearshore Marine Sediments

Proteinaceous material in marine sediments which is available to proteolytic hydrolysis has been measured using a new method. This technique utilizes Coomassie Blue dye binding, which has the advantage of being sensitive only to larger polypeptides. Substantial interferences from other sedmentary organic substances are overcome by using a standard additions approach in conjunction with enzymatic digestion of the protein. Although tedious, the technique provides acceptable precision and accuracy. Measurements of protein in surficial nearshore sediments of the Gulf of Maine and St. Croix yield values ranging from 0.1 to 2.2 mg g-1, which account for a minor fraction of total nitrogen or acid-hydrolyzable amino acids. Protein decreases downcore at a faster rate than either of these 2 indicators of nitrogenous material, indicating the greater lability of the truly proteinaceous material. Biomass comprises a minor portion of the measured protein

Region and volume dependencies in spectral linewidth assessed by 1H 2D chemical shift imaging in the monkey brain at 7T

High magnetic fields increase the sensitivity and spectral dispersion in MR spectroscopy. In contrast, spectral peaks are broadened in vivo at higher field strength due to stronger susceptibility-induced effects. Strategies to minimize the spectral linewidth are therefore of critical importance. In the present study, 1H 2D chemical shift imaging (CSI) at short echo time was performed in the macaque monkey brain at 7 T. Dependencies of spectral linewidth on the CSI voxel size were determined by data reconstruction at different spatial resolution. An overall linewidth narrowing at increased spatial resolution is shown and regional differences are demonstrated