On the Relation Between U q (sl(2)) Vertex Operators and q-Zonal Functions

We show how the states constructed from the action of the modes of bosonized vertex operators that intertwine U modules are related toq -zonal functions.     

BIOLOGICAL ACTIVITIES OF PHTHALOCYANINES-IX. PHOTOSENSITIZATION OFV–79 CHINESE HAMSTER CELLS ANDEMT–6 MOUSE MAMMARY TUMOR BY SELECTIVELY SULFONATED ZINC PHTHALOCYANINES

Abstract— Zinc phthalocyanines sulfonated to different degrees are tested for their ability to sensitizeV–79 Chinese hamster cells andEMT–6 mouse mammary tumors to red light. In vitro , the lower sulfonated derivatives were the most active with the exception of the poorly water-soluble monosulfonated dye. An isomeric mixture of tetrasulfonated derivatives obtained via direct sulfonation was ten times more active than the homogeneous tetrasulfo derivative prepared via the condensation of sulfophthalic acid. In vivo , the latter dye was completely inactive, whereas the remainder of the sulfonated preparations exhibited a similar structure-activity pattern as observed with theV–79 cells in vitro . The disulfonated zinc phthalocyanine showed the best tumoricidal activity in the series and also appeared to be a more efficient photosensitizer of cell inactivation and tumor cure than the aluminum or gallium complexes as well as hematoporphyrin derivative preparations. No significant differences in skin phototoxicity were observed among the various dyes.     

THE EFFECT OF CLIMATE CHANGE ON WETLANDS AND WATERFOWL IN WESTERN CANADA: INCORPORATING CROPPING DECISIONS INTO A BIOECONOMIC MODEL

Abstract We extend an earlier bioeconomic model of optimal duck harvest and wetland retention in the Prairie Pothole Region of Western Canada to include cropping decisions. Instead of a single state equation, the model has two state equations representing the population dynamics of ducks and the amount of wetlands. We use the model to estimate the impact of climate change on wetlands and waterfowl, including direct climate effects as well as land use change due to biofuel policies aimed at mitigating climate change. The model predicts that climate change will reduce wetlands by 37–56% from historic levels. Land use change due to biofuel policies is expected to reduce wetlands by between 35% and 45% from historic levels, whereas direct climate effects will range from a reduction of 2–11%, depending on the future climate scenario. This result indicates that models that neglect the effect of land use changes underestimate the effect of climate change on wetlands. Further, wetlands loss is geographically heterogeneous, with losses being the largest in Saskatchewan.     

On the positive nonoscillatory solutions of the difference equation x_(n+1)= α +(x_(n-K)/x_(n-m))~p

The aim of this paper is to show that the following difference equation:xn+1=α+(xn-k/xn-m)p,n=0,1,2…,where α＞-1,p＞0,k,m ∈ N are fixed, 0≤m＜k,x-k,x-k+1,…,x-m,…,x-1,x0 are positive, has positive nonoscillatory solutions which converge to the positive equilibrium x=α+1.It is interesting that the method described in the paper, in some cases can also be applied when the parameter α is variable.     

A geometric approach to direct minimization

The approach presented, geometric direct minimization (GDM), is derived from purely geometrical arguments, and is designed to minimize a function of a set of orthonormal orbitals. The optimization steps consist of sequential unitary transformations of the orbitals, and convergence is accelerated using the Broyden-Fletcher-Goldfarb-Shanno (BFGS) approach in the iterative subspace, together with a diagonal approximation to the Hessian for the remaining degrees of freedom. The approach is tested by implementing the solution of the self-consistent field (SCF) equations and comparing results with the standard direct inversion in the iterative subspace (DIIS) method. It is found that GDM is very robust and converges in every system studied, including several cases in which DIIS fails to find a solution. For main group compounds, GDM convergence is nearly as rapid as DIIS, whereas for transition metal-containing systems we find that GDM is significantly slower than DIIS. A hybrid procedure where DIIS is used for the first several iterations and GDM is used thereafter is found to provide a robust solution for transition metal-containing systems.     

TYPES I AND II SENSITIZED PHOTOOXIDATION OF AMINOACID BY PHTHALOCYANINES: A FLASH PHOTOCHEMICAL STUDY

Abstract— In connection with the use of red light-photosensitizers for photodynamic therapy, the redox reactivity of excited metallophthalocyanines (M = Al, Ga) was investigated by flash photolysis in order to establish whether photooxidations proceed by Foote's mechanisms I or II. Aminoacids (tryptophan, tyrosine) were seen to function as electron transfer quenchers of the excited phthalocyanines with rate constants 10⁷ k 10⁴ M ^-1 s^-1. This was not the case of purines or ATP. The ability of the excited phthalocyanines to sensitize photooxidations by mechanisms I and II is discussed in terms of evaluated rate constants.     

ACTION SPECTRA FOR ULTRAVIOLET KILLING AND PHOTOREACTIVATION IN THE BLUE-GREEN ALGA AGMENELLUM QUADRUPLICATUM

Abstract— The action spectrum for photoreactivation has been determined in a coccoid blue-green alga, Agmenellum quadruplicatum. The spectrum is rather similar to that recorded for Streptomyces griseus conidia, with some suggestion of a little more structure. The action spectrum suggests possible carotenoid involvement; however, no other evidence for this could be found. The action spectrum for u.v. killing is also broad with some evidence of fine structure. The possible implication of tetrahydropteridines or c -phycocyanin as chromophores in the region 240–300 nm, along with DNA, is pointed out.     

AN APPROXIMATE PROJECTION SCHEME FOR INCOMPRESSIBLE FLOW USING SPECTRAL ELEMENTS

An approximate projection scheme based on the pressure correction method is proposed to solve the Navier–Stokes equations for incompressible flow. The algorithm is applied to the continuous equations; however, there are no problems concerning the choice of boundary conditions of the pressure step. The resulting velocity and pressure are consistent with the original system. For the spatial discretization a high-order spectral element method is chosen. The high-order accuracy allows the use of a diagonal mass matrix, resulting in a very efficient algorithm. The properties of the scheme are extensively tested by means of an analytical test example. The scheme is further validated by simulating the laminar flow over a backward-facing step.     

自锁定半导体激光器中强度压缩及位相噪声的减小

采用外部F-P腔自锁定单模量子阱半导体激光器，观察到强度噪声的压缩现象，并同时大幅度降低了位相起伏.在35MHz附近观察到19.3%的强度压缩，对应激光输出的压缩度为37.8%，在9kHz-100MHz范围内观察到约3个数量级的位相噪声降低.获得了近最小测不准态. 关键词：