A Rank Minrelation - Majrelation Coefficient

Improving the detection of relevant variables using a new bivariate measure could importantly impact variable selection and large network inference methods. In this paper, we propose a new statistical coefficient that we call the rank minrelation coefficient. We define a minrelation of X to Y (or equivalently a majrelation of Y to X) as a measure that estimate p(Y > X) when X and Y are continuous random variables. The approach is similar to Lin's concordance coefficient that rather focuses on estimating p(X = Y). In other words, if a variable X exhibits a minrelation to Y then, as X increases, Y is likely to increases too. However, on the contrary to concordance or correlation, the minrelation is not symmetric. More explicitly, if X decreases, little can be said on Y values (except that the uncertainty on Y actually increases). In this paper, we formally define this new kind of bivariate dependencies and propose a new statistical coefficient in order to detect those dependencies. We show through several key examples that this new coefficient has many interesting properties in order to select relevant variables, in particular when compared to correlation

Trifluoromethyl-substituted polymers

The synthesis of polymers is discussed. It includes: (1) the synthesis of fluorine-containing crosslinked poly(ether ketones); (2) the synthesis and characterization of poly(imide amides) and their N-methylated analogues; (3) the synthesis of fluorine-containing aromatic polyethers; (4) the synthesis of novel fluorine-containing aromatic polysiloxanes; and (5) the conversion of 6F-containing polythioethers to polysulfones. It is hoped that these polymers will find use as low dielectric materials in electronic applications, function as thermal control coatings, or be suitable elastomeric sealants for extreme service conditions

Kinetics of the photolysis of benzenetricarbonylchromium(0) in chloroform

In contrast to the photolysis of Cr(CO)3(C6H6) in nonhalogenated solvents, in which the products are CrL(CO)2(C6H6) in the presence of a donor L, or Cr(CO)6 and C6H6 if no donor is present, the photo-reaction in chloroform yields CrCl3. No significant portion of the reaction occurs through absorption of 254nm light by CHCl3• The quantum yield is 1.4, consistent with a mechanism in which several radicals are formed upon chlorination of the chromium, which then cause further decomposition of the reactant. In 24% CCl4, the reaction still occurs primarily through the excited state metal complex, but there is a solvent-initiated contribution, which is more significant the lower the reactant concentration. The quantum yield for the solvent-initiated pathway is 0.3 in 24% CCL4