Let finite source and reproduction alphabets X and Y and a distortion measure d : X ×Y → [0,∞) be given. We study the minimum asymptotic rate required to describe a source distributed over X within a (given) distortion threshold D at every sample. The problem is hence a min-max problem, and the distortion measure is extended to vectors as follows: for x ∈ X, y ∈ Y, d(x, y) = maxi d(xi, yi). In ...

Given a set P of n points in R, a typical clustering problem asks for partitioning P into a family of k subsets {P1, . . . , Pk}, so that a certain objective function is minimized. The objective function depends on the application and varies. A typical clustering problem is the so-called centered clustering problem in which a representative point ci (or a q-flat) is chosen for each cluster Pi a...

We present a structured perturbation theory for the LDU factorization of (row) diagonally dominant matrices and we use this theory to prove that a recent algorithm of Ye (Math Comp 77(264):2195–2230, 2008) computes the L , D andU factors of these matrices with relative errors less than 14n3u, where u is the unit roundoff and n × n is the size of the matrix. The relative errors for D are compone...

Using the patch-clamp technique, we have identified large-conductance (maxi) K+ channels in the apical membrane of Necturus gallbladder epithelium, and in dissociated gallbladder epithelial cells. These channels are more than tenfold selective for K+ over Na+, and exhibit unitary conductance of approximately 200 pS in symmetric 100 mM KCl. They are activated by elevation of internal Ca2+ levels...

The eye's aqueous humor is secreted by a bilayered ciliary epithelium comprising pigmented (PE) and nonpigmented (NPE) epithelial cell layers. Stromal Cl(-) enters the PE cells and crosses gap junctions to the NPE cells for release into the aqueous humor. Maxi-Cl(-) channels are expressed in PE cells, but their physiological significance is unclear. To address this question, excised patches and...

Intracellular K+ plays an important role in controlling the cytoplasmic ion homeostasis for maintaining cell volume and inhibiting apoptotic enzymes in the cytosol and nucleus. Cytoplasmic K+ concentration is mainly regulated by K+ uptake via Na+-K+-ATPase and K+ efflux through K+ channels in the plasma membrane. Carbonyl cyanide p-trifluoromethoxyphenylhydrazone (FCCP), a protonophore that dis...

Romero, Fernando, Bagnólia A. Silva, Viviane L. A. Nouailhetas, and Jeannine Aboulafia. Activation of Ca21activated K1 (maxi-K1) channel by angiotensin II in myocytes of the guinea pig ileum. Am. J. Physiol. 274 (Cell Physiol. 43): C983–C991, 1998.—We investigated the regulation of the Ca21-activated K1 (maxi-K1) channel by angiotensin II (ANG II) and its synthetic analog, [Lys2]ANG II, in fres...

We consider the following problem given a pla nar straight line graph nd a covering triangulation whose maximum angle is as small as possible A cov ering triangulation is a triangulation whose vertex set contains the input vertex set and whose edge set con tains the input edge set The covering triangulation problem di ers from the usual Steiner triangulation problem in that we may not add a ver...

High-conductance calcium-activated potassium (Maxi-K) channels are present in smooth muscle where they regulate tone. Activation of Maxi-K channels causes smooth muscle hyperpolarization and shortening of action-potential duration, which would limit calcium entry through voltage-dependent calcium channels leading to relaxation. Although Maxi-K channels appear to indirectly mediate the relaxant ...

The opportunity to increase cassava productivity can be done through cultivation technology improvement. research aimed obtain information on the suitability of agroecology, agro-economy, and strategy planning for developing as local food. Research was carried out in 2021 form survey field experiment Sukabumi Regency, West Java. Data analysis that used is Random Block Design SWOT data. results ...