Convex dominates concave: An exclusion principle in discrete-time Kolmogorov systems

We establish an exclusion principle in discrete-time Kolmogorov systems by using average Liapunov functions. The exclusion principle shows that a weakly dominant species with a convex logarithmic growth rate function eliminates species with concave logarithmic growth rate functions. A general result is applied to specific population models. This application gives an improved exclusion principle for the specific population models.

     

Degree Sums and Covering Cycles

It is shown that if in a simple graph G of order n the sum of degrees of any three pairwise non-adjacent vertices is at least n, then there are two cycles (or one cycle and an edge or a vertex) of GF that contain all the vertices. © 1995 John Wiley & Sons, Inc.     

Structural and electronic properties of a new molecular conductor, α-(BEDT-TTF)2CsCd(SCN)4

Structural and electronic properties of a new BEDT-TTF based radical cation salt, α-(BEDT-TTF)₂CsCd(SCN)₄, are presented. In the measurements of the electrical resistivity and the magnetic susceptibility, this new α-type salt shows metallic behavior down to low temperature. Measurements of the resistivity under in-plane c-axial strain reveal a newly observed insulating phase, suggesting that α-(BEDT-TTF)₂CsCd(SCN)₄ is placed near an insulating phase which might have close relationships with a superconducting phase realized in α-type salts.     

Prompt Gamma-Ray Analysis of Rats

Prompt -ray analysis with the internal monostandard method was used to organs taken from rats. After B or Cd was administered, the B/H and Cd/H contents ratios were determined in the brain, kidney, and liver to study their distribution and metabolism. Boron was distributed in all organs but metabolized quickly. Cd was slowly accumulated in the liver and kidneys during the 65 hours studied but no Cd was detected in the brain.     

Change of concentrations of trace elements and protein contents in the liver of zinc deficient mice

The concentrations of essential trace elements and proteins in cytosolic fraction of hepatic cells of mice fed with Zn-deficient diet (Zn-def, mice) and control were determined by ICP-MS and BCA protein assay method, respectively, after division into forty fractions by gel filtration chromatography. The concentrations of zinc and proteins decreased in the 14–17th fractions of Zn-def, mice, whereas cobalt concentrations increased in the 14, 17, and 18th fractions. However, no significant differences were found on the gel after SDS-PAGE for the 12–21st fractions, although the BCA protein assay date showed the decrease of protein amounts in 13–15th fractions of Zn-def. mice.     

Multitracer study on permeation of rare earth elements through a supported liquid membrane

Separation by means of supported liquid membranes is a useful method for the preparation and preconcentration of radioactive nuclides. The permeation of rare earth elements through a bis(2-ethylhexyl) hydrogen phosphate-decalin membrane supported on a microporous polytetrafluoroethylene sheet was studied using a multitracer containing radioactive nuclides of Sc, Zr, Nb, Hf, Ce, Pm, Gd, Yb, and Lu. Permeation rates of these elements from feed solutions of various acidity to receiving solutions of 0.5 mol·dm⁻³ HCl were determined simultaneously. The feed solution at pH 1.4 gave the highest permeation rate for Ce, Pm, and Gd, amounting to about 95% of permeation for Ce and Pm, 80% for Gd, and 10% for Yb in 21 h. Scandium, Zr, Nb, Hf, and Lu were not transported at all from the feed solution. Permeation rates of Yb and Lu from the feed solution at pH 1.4 to receiving solutions of 0.75, 1.0, 2.3, and 4.0 mol·dm⁻³ HCl increased with the concentration. The results obtained indicate that the light rare earth elements can be separated from the heavy ones by this method.     

Photoelectrochemistry of p-type Cu2O semiconductor electrode in ionic liquid

We investigated the photoelectrochemical characteristics and photo-stability of Cu₂O layered on a copper plate using a hydrophobic ionic liquid. Our findings revealed that Cu₂O is stable under white light irradiation, provided water is removed from the electrolyte. Methyl viologen derivative, a well-established electron acceptor, was introduced to the ionic liquid electrolyte, allowing the photo-induced electron transfer reaction at the Cu₂O/electrolyte interface to be characterized. The methyl viologen derivative exhibited two distinct redox reactions at −0.56 V and −0.98 V vs. Ag/AgCl, clearly indicating that no dimer formation or co-proportionation reaction occurred. The excessive photocurrents being continuously generated resulted from a viable photo-induced electron transfer reaction from the Cu₂O to the acceptor. However, in contrast, the reduction of the Cu₂O by water in the aqueous solution causes this electron transfer to be inhibited. We further demonstrate that these findings are vital to understanding the role of the Cu₂O and its photoelectrochemical applications.