Making Use of Incomplete Observations for Regression in Bivariate Normal Model

Two estimates of the regression coefficient in bivariate normal distribution are considered: the usual one based on a sample and a new one making use of additional observations of one of the variables. They are compared with respect to variance. The same is done for two regression lines. The conclusion is that the additional observations are worth using only when the sample is very small.     

Acyclovir terminated thiophosphate dendrimers

An efficient synthesis of antiviral dendritic prodrug candidates, water-soluble, polyanionic conjugates of 1st and 2nd generation thiophosphate dendrimers with acyclovir, is described.     

Comparison of Several Calibration Procedures for Glass Electrodes in Proton Concentration

Several reported procedures for calibrating glass electrodes in proton concentration are compared. Some recommendations for non-experts are also given. The examined procedures can be classified into two broad categories, namely: those based on direct potential difference measurements of solutions of known proton concentration and those that use one or several pH standards to calibrate the electrode and subsequently measure the pH of solutions containing known proton concentrations. With a single buffer, the two types of procedures lead to equivalent results. However, if two pH buffers are used, the slope of the calibration graph in proton concentration will differ from the real electrode slope to an extent proportional to the difference between the liquid junction potentials of the two buffers. Therefore, any other method is preferable under these circumstances.     

Searching for new conditions for fermion N-representability

New elements of the dual cone of the set of fermion N-representable 2-density operators are proposed. So far, the explicit form of the corresponding necessary conditions for N-representability is obtained for N = 3. In this case the new condition is stronger than the known B- and C-conditions for 3-representability. The results provide evidence that in the spectral decomposition of the N-representable 2-density operator there exists an intrinsic relation between the eigenvalue and the corresponding eigenfunction.     

Thermal Analysis in Examination of Reduction of Blast Furnace Pellets

This paper presents applications of thermal analysis to observe the course of reduction of acidic pellets, metallurgical substances whose reducibility and strength are basic parameters of use in blast furnace processes. Both parameters depend on the mineral composition of the samples. The investigations included determination of the chemical and phase compositions of the initial samples and reduction products. Research was conducted on acidic pellets from Połtawa (Poland), applied in the T. Sendzimir Steelworks (Poland), in comparison with pellets from Brazil, Canada and Lebedyn (Russia). This revised version was published online in August 2006 with corrections to the Cover Date.     

On mechano-chemical Calcium waves

The influence of mechano-chemical coupling on calcium concentration waves is considered. The propagation of calcium waves is described by a reaction–diffusion equation with the reaction term dependent on the mechanical stress responsible for the release of calcium. Similarly the balance of mechanical forces is influenced by the calcium concentration through the so-called traction force.