6,484 research outputs found
Electrochemistry and Adsorption of Bis 2,2â˛âBipyridinecobalt(I) and Bis 6,6â˛âDimethylâ2,2â˛âBipyridinecobalt(I) in Acetonitrile
Cyclic voltammetry, coulometry, and chronocoulometry were used to examine the reduction of
bisâ2,2â˛âbipyridinecobalt(II), Co(bipy)^(2+)_2 , and
bisâ6,6â˛âdimethylâ2,2â˛âbipyridinecobalt(II), Co(dmbp)^(2+)_2 in acetonitrile solution. Both of the cobalt(I) reduction products, Co(bipy)^(+)_2 and Co(dmbp)^(+)_2 , adsorb on mercury but not on graphite or platinum electrodes. Formula decomposes at a modest rate while Formula is much more stable. Neither reduced complex proved effective as a catalyst for the electroreduction of nitrous oxide or alkyl halides
Grouping of coefficients for the calculation of inter-molecular similarity and dissimilarity using 2D fragment bit-strings
This paper compares 22 different similarity coefficients when they are used for searching databases of 2D fragment bit-strings. Experiments with the National Cancer Institute's AIDS and IDAlert databases show that the coefficients fall into several well-marked clusters, in which the members of a cluster will produce comparable rankings of a set of molecules. These clusters provide a basis for selecting combinations of coefficients for use in data fusion experiments. The results of these experiments provide a simple way of increasing the effectiveness of fragment-based similarity searching systems
Grouping of coefficients for the calculation of inter-molecular similarity and dissimilarity using 2D fragment bit-strings
This paper compares 22 different similarity coefficients when they are used for searching databases of 2D fragment bit-strings. Experiments with the National Cancer Institute's AIDS and IDAlert databases show that the coefficients fall into several well-marked clusters, in which the members of a cluster will produce comparable rankings of a set of molecules. These clusters provide a basis for selecting combinations of coefficients for use in data fusion experiments. The results of these experiments provide a simple way of increasing the effectiveness of fragment-based similarity searching systems
ASYMMETRIC PRICE RELATIONSHIPS IN THE U.S. BROILER INDUSTRY
This study presents a testing methodology to analyze potential price asymmetries among the farm, wholesale, and retail levels of the U.S. broiler industry. Lag length, direction of causality and power of the integrators in the industry have allowed the wholesale price to become the center, causal price in the market. Asymmetric price transmissions, however, are limited. While downward movements in the wholesale price are passed on more fully to growers than increases in the wholesale price, only consumers in the North Central region of the U.S. share a larger portion of wholesalers' price increases than price decreases.Asymmetry, Broilers, Concentration, Granger causality, Price transmission, Demand and Price Analysis, Livestock Production/Industries,
Clustering files of chemical structures using the Szekely-Rizzo generalization of Ward's method
Ward's method is extensively used for clustering chemical structures represented by 2D fingerprints. This paper compares Ward clusterings of 14 datasets (containing between 278 and 4332 molecules) with those obtained using the SzekelyâRizzo clustering method, a generalization of Ward's method. The clusters resulting from these two methods were evaluated by the extent to which the various classifications were able to group active molecules together, using a novel criterion of clustering effectiveness. Analysis of a total of 1400 classifications (Ward and SzĂŠkelyâRizzo clustering methods, 14 different datasets, 5 different fingerprints and 10 different distance coefficients) demonstrated the general superiority of the SzĂŠkelyâRizzo method. The distance coefficient first described by Soergel performed extremely well in these experiments, and this was also the case when it was used in simulated virtual screening experiments
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Diet, nutrition, and avoidable cancer
In a 1981 review, Doll and Peto estimated that approximately 35% of cancer deaths in the United States were potentially avoidable by the modification of diet but that this percentage might be as low as 10% or as high as 70%. Since that time, the epidemiologic literature on diet and cancer has grown greatly, as has understanding of the mechanisms of carcinogenesis. In general, this expanded literature has not provided reason to alter the Doll and Peto estimate substantially. For colon cancer, evidence has accumulated that some of the international differences that were attributed to diet are probably due to physical activity. For breast cancer, the concept that fat intake per se is the primary reason for differences in rates among countries has not been supported by prospective studies. Although several lines of evidence suggest that caloric restriction and slow growth rates may contribute importantly to the low rates of breast cancer found outside Western countries, this may not translate directly to practical means of prevention. In contrast to breast cancer, more recent data have supported a causative role for red meat in the development of colon and prostate cancers, although perhaps not entirely due to its fat content. Whereas earlier thinking about nutrition and cancer emphasized the adverse effects of fat and other components in the diet, the most compelling evidence of the last decade has indicated the importance of protective factors, largely unidentified, in fruits and vegetables. Considering the more recent evidence, it is roughly estimated that about 32% of cancer may be avoidable by changes in diet; however, it now seems unlikely that less than 20% or more than 42% of cancer deaths would be avoidable by dietary change
Synoptic studies in fog
This study of fog formations at Hadley Airport was carried out during the winter of 1928-29 with the intent of finding out how far a careful scrutiny of local records might assist in explaining and forecasting local fogs. It was meant to be supplementary to a more general discussion of fog
and haze formation which had appeared previously in the Monthly Weather Review for November, 1928. This study is based on the general fog classification set forth there
Discussion and illustration of problems suggested by the analysis of atmospheric cross-sections
The preparation of atmospheric cross-sections, in which the fields of the various
meteorological elements are represented in the vertical plane containing a number of
synoptic aerological soundings, has long been a part of the technique applied to the
investigation of problems in synoptic meteorology. However, owing to the lack of adequate
observational material, the number of such cross-sections prepared in the past
has been very small. The method was applied only in a few cases chosen for careful
analysis and study. Consequently no uniform technique of analysis of such cross-sections
has been developed, nor have the possibilities of this method of synoptic investigation
received much attention.
In the fall of 1933 the author decided that the possibilities of the cross-section method
of synoptic representation warranted the systematic preparation and analysis of a large
number of cross-sections. For this purpose a number of periods during which the synoptic
maps seemed to indicate interesting atmospheric developments, and for which numerous
aerological observations were available, were chosen from the maps of the preceding
two or three years for detailed cross-sectional study. In all, ten periods of from
two to six days each were chosen, a total of 36 days, entailing the preparation of about
90 cross-sections, and the use of about 400 aerological soundings
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