In the crystal structure of the title one-dimensional coordination polymer, [Y(2)(C(8)H(3)NO(6))(2)(C(2)O(4))(H(2)O)(6)]·3H(2)O, each Y(III) ion is bridged to its neighbours by two 5-nitro-benzene-1,3-dicarboxyl-ate (nbdc) dianions and one oxalate dianion (located on an inversion centre) to form a ladder-like polymeric structure. The two carboxylate groups of nbdc assume different modes of coor...

In the title complex, [Pr(C(9)H(4)N(2)O(4))(C(2)H(3)O(2))(H(2)O)](n), the Pr(III) ion is coordinated by five O atoms and one N atom from four benzimidazole-5,6-dicarboxyl-ate ligands, two O atoms from an acetate ligand and one water mol-ecule, giving a tricapped trigonal-prismatic geometry. The benzimidazole-5,6-dicarboxyl-ate and acetate ligands connect the Pr(III) ions, forming a layer in the...

In the title compound, NH(4) (+)·(C(2)H(5)O)(2)PS(2) (-), the ammonium cation is connected by four charge-assisted N-H⋯S hydrogen bonds to four tetra-hedral O,O'-diethyl dithio-phosphate anions, forming layers parallel to (100). The polar and non-polar constituents of the layers are stacked alternately along [100]. Inter-lacing of the external ethyl groups through van der Waals inter-actions co...

Abst ract . A c -a utomaton is a part icularl y sim ple type of cellu la r automaton on a grap h; each cell is either in stale 0 or 1 and the next sta te of a cell is determined by addi ng the sta tes of it s neighbors modulo two . Using algebraic an d gra ph-theoretic techniques, questions such as reversibility and existe nce of predecessor configura tions of th ese automata will be st udied ....

The P atom in the title compound, C(8)H(18)NO(2)PS, is bonded in a distorted tetra-hedral PSO(2)N environment with bond angles in the range of 99.23 (5)-115.17 (4)°. The cyclo-hexane ring is disordered over two sets of sites with refined occupancies of 0.528 (5) and 0.472 (5). The ring in both disorder components adopts a chair conformation with the N-H group oriented equatorially. In the cryst...

Hierarchical terrain models describe a topographic surface at di erent levels of detail, providing a multiresolution representation as well as a data compression mechanism. In this paper, we consider the problem of computing the visibility map, with respect to a xed viewpoint, on a hierarchical triangle-based terrain model. This problem presents two aspects: the extraction of a visibility map a...

The asymmetric unit of the polymeric title compound, [Mg(3)(C(9)H(3)O(6))(2)(C(3)H(7)NO)(4)](n), contains three Mg(II) ions bridged by carboxyl-ate O atoms from two fully deprotonated benzene-1,3,5-tricarboxyl-ate (BTC) trianions and four metal-coordinated dimethyl-formamide (DMF) mol-ecules. One Mg(II) ion is octa-hedrally coordinated by six carboxyl-ate O atoms. The other two cations are each...

our studi es have shown normal cyclical patterns of ovarian stero ids and pituitary gonadotropines in pa tients with congenital absccncc o f th e uteru s. it appears that the life-long abscence of a fun ctioning uterus has no effect o n the fun ctional life span o f t he co rpus lurer um, but may have some effect in the level o f estrogenes iu th e seco nd half of the cycle.

In this paper, we present the Euler’s partition theorem, which states that for every natural number the number of odd partitions is equal to the number of strict partitions. First, we prove this theorem bijectively and then using generating functions. We present two Sylvester’s bijections which, besides proving Euler’s theorem, also give a few other refinements. Fine’s theorem is illustrated by...