In this paper we classify the four dimensional gradient shrinking solitons under certain curvature conditions satisfied by all solitons arising from finite time singularities of Ricci flow on compact four manifolds with positive isotropic curvature. As a corollary we generalize a result of Perelman on three dimensional gradient shrinking solitons to dimension four.

Efficient algorithms for the computation of optimum stable models are based on unsatisfiable core analysis. However, these algorithms essentially run to completion, providing few or even no suboptimal stable models. This drawback can be circumvented by shrinking unsatisfiable cores. Interestingly, the resulting anytime algorithm can solve more instances than the original algorithm.

∣ 2 u dV. This implies in particular that d dt μ(g(t), τ(t)) ≥ 0 with equality exactly for homothetically shrinking solutions of Ricci flow. An important consequence of this entropy formula is a lower volume ratio bound for solutions of Ricci flow on a closed manifold for a finite time interval [0, T ) asserting the existence of a constant κ > 0, only depending on n, T and g(0), such that the i...

The leaching reaction kinetics of weathered crust elution-deposited rare earth with mixed ammonium salts was studied. The in uence of concentration of reagents and particle size of ore on leaching rate was investigated. The results showed that the di usion process and leaching rate could be improved by increasing reagents concentration and decreasing leaching owing rate and particle size. The l...

The leaching kinetics of a low-grade zinc oxide ore in different acid media was investigated with respect to the experimental variables including acid concentration, temperature, liquid to solid (L/S) ratio, and stirring speed. The results obtained showed that the leaching reagent concentration and the reaction temperature exerted significant effects on the extraction of zinc, whereas the L/S r...

A kinetic study of cadmium and lead biosorption to a brown alga, Kjellmaniella crassiforia, was carried out. The shrinking core model derived by M. Gopala Rao and A. K. Gupta (Chem. Eng. J.24, 181, (1982)) was modified and adapted for description of the rate process of cadmium and lead biosorption to the alga. The biosorption rate process was well described and average apparent diffusion coeffi...

the objective of the present study was to identify managerial competencies. this study reviewed existing managerial competencies in a cultural context resulting in the development of a broad based psychometrically sound leadership questionnaire. the unit of analysis of the research was a theoretical and experimental research related to managerial competencies, provided from seventeen iranian an...

In this correspondence, it is given a correction to Theorem 4 in Y. Hu, and G. Xiao, “Generalized Self-Shrinking Generator,” IEEE Transactions on Information Theory, vol. 50, No. 4, pp. 714-719, April 2004.

In 2004, Y. Hu and G. Xiao introduced the generalized self-shrinking generator, a simple bit-stream generator considered as a specialization of the shrinking generator as well as a generalization of the self-shrinking generator. The authors conjectured that the family of generalized self-shrinking sequences took their least periods in the set {1, 2, 2}, where L is the length of the Linear Feedb...