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71.
The reaction of some diheterocyclic iodonium salts with a variety of nucleophiles has been studied. The reaction was of preparative use for the syntheses of thiocyano, phenylsulfinyl and phenoxy derivatives of thiophenes and furans. 相似文献
72.
Jokinen IE Markkula ES Salo HM Kuhn P Nikoskelainen S Arts MT Browman HI 《Photochemistry and photobiology》2008,84(5):1265-1271
Atlantic salmon (Salmo salar) parr were exposed in two outdoor experiments, ranging in duration from 52 to 137 days, to spectral treatments: (1) natural sunlight (=present ambient UVB level), (2) solar radiation supplemented with enhanced UVB radiation from lamps simulating 20% or 8% stratospheric ozone loss or (3) UVB-depleted sunlight achieved by screening with Mylar-D film. The growth, condition and immune function of the salmon were quantified after treatments. Exposure to enhanced UVB radiation retarded growth, and decreased hematocrit value and plasma protein concentration. Further, enhanced UVB radiation affected plasma immunoglobulin concentration. The results demonstrate that juvenile Atlantic salmon are not able to fully adapt to increased ambient UVB levels in long-term exposures, and the interference with immune system function suggests a negative effect of UVB on disease resistance in Atlantic salmon. 相似文献
73.
In the selection of investment projects, it is important to account for exogenous uncertainties (such as macroeconomic developments) which may impact the performance of projects. These uncertainties can be addressed by examining how the projects perform across several scenarios; but it may be difficult to assign well-founded probabilities to such scenarios, or to characterize the decision makers’ risk preferences through a uniquely defined utility function. Motivated by these considerations, we develop a portfolio selection framework which (i) uses set inclusion to capture incomplete information about scenario probabilities and utility functions, (ii) identifies all the non-dominated project portfolios in view of this information, and (iii) offers decision support for rejection and selection of projects. The proposed framework enables interactive decision support processes where the implications of additional probability and utility information or further risk constraints are shown in terms of corresponding decision recommendations. 相似文献
74.
In this note we show that on any compact subdomain of a Kähler manifold that admits sufficiently many global holomorphic functions, the products of harmonic functions form a complete set. This gives a positive answer to the linearized anisotropic Calderón problem on a class of complex manifolds that includes compact subdomains of Stein manifolds and sufficiently small subdomains of Kähler manifolds. Some of these manifolds do not admit limiting Carleman weights, and thus cannot be treated by standard methods for the Calderón problem in higher dimensions. The argument is based on constructing Morse holomorphic functions with approximately prescribed critical points. This extends earlier results from the case of Riemann surfaces to higher dimensional complex manifolds. 相似文献
75.
Comprehensive self-assembly studies for nine bile acid amides of amino acid esters are reported. The number of the hydroxyl groups attached to the steroidal skeleton and the character of the amino acid ester moiety were used as variables when examining the self-assembly properties of the compounds. Two of the compounds were shown to undergo self-assembly leading to organogelation. In addition, preliminary self-assembly studies in aqueous mixtures of polar organic solvents were conducted. Microscopic methods (optical microscopy and scanning electron microscopy) were utilised in order to gain a deeper insight into the self-assembled structures. Furthermore, single-crystal X-ray structures for three of the compounds were solved. 相似文献
76.
We show that on simple surfaces the geodesic ray transform acting on solenoidal symmetric tensor fields of arbitrary order is injective. This solves a long standing inverse problem in the two-dimensional case. 相似文献
77.
For entire Dirichlet series of the form
, we establish conditions under which the relation
holds uniformly in
outside a certain set E for which
where h() is a positive continuous function increasing to + on [0, +). 相似文献
78.
Metalation of 1-methylpyrrole using n-butyllithium and tetramethylethylenediamine (TMEDA) in ether furnished 1-methyl-2-pyrrolyllithium, which in turn was converted to 1-methyl-2-methylthiopyrrole upon treatment with dimethyldisulfide. Further formylation with dimethylformamide, phosphorus oxychloride in dichloroethane led to the corresponding pyrrole-2-carboxaldehyde, which was then condensed with malononitrile and methylcyanoacetate under Knoevenagel reaction conditions to give 2-cyano-3-(1-methyl-5-methylthio-2-pyrrolyl)acrylonitrile and 2-cyano-3-(1-methyl-5-methylthio-2-pyrrolyl)acrylic acid methyl ester, respectively. Their oxidation by hydrogen peroxide furnished the corresponding sulfones. Analogously, 5-phenylthio derivatives were prepared. 相似文献
79.
A. P. Voronov V. I. Salo V. M. Puzikov V. B. Distanov L. D. Patsenker 《Crystallography Reports》2006,51(1):150-156
The conditions for growth of single crystals of potassium dihydrogen phosphate KH2PO4 activated by organic phosphors were investigated. Aqueous solutions of derivatives of naphthalic and perylenetetracar-boxylic acids were used as activators. A possible scheme of coherent matching of crystallochemical parameters of the KH2PO4 lattice with an organic activator molecule is proposed. The excitation and photoluminescence spectra of the activated crystals are measured in the range 200–600 nm. It is ascertained that the luminescence is related to the presence of organic phosphors in the KH2PO4 lattice. 相似文献
80.
Intense focus on student achievement results in mathematics and science has brought about claims that K‐12 teachers should be better prepared to teach basic concepts in these disciplines. The focus on teachers' mathematics and science content knowledge has been met by efforts to increase teacher knowledge through funded national initiatives focusing on mathematics and science. The purpose of the present study was to look across projects in the National Science Foundation's Math and Science Partnership Program to determine how partnerships developed processes for measuring growth in teacher content knowledge. Pre‐ and post‐testing was the most common process for measuring growth in content knowledge, with 63% of the mathematics and 78% of the science teachers showing significant gains in content knowledge. A notable difference was found between teacher outcomes when the Learning Mathematics for Teaching instrument was used in comparison with the use of other instruments measuring teacher content knowledge growth. Results revealed two pathways for promoting teacher content knowledge growth: content explicit, where the goal of growth in teacher content knowledge was explicit in the activity, and content embedded, where the goal of growth in teacher content knowledge was embedded in the activity. As a result of the analysis, a framework demonstrating the interrelationships among processes and pathways was developed. 1 相似文献