Transcription of the Balbiani ring (BR) genes of the dipteran Chironomus tentans was inhibited by teh nucleoside analogue DRB (5,6-dichloro-1-beta-D-ribofuranosyl benzimidazole). The BR genes were emptied of RNA polymerases and the subsequent packing of the genes was monitored by transmission electron microscopy. The thin chromatin axis of the transcriptionally active genes condensed into a thi...

The set packing and set covering models are two useful models in integer programming. Sometimes, due to the special structure of the constraint matrix, the natural linear programming relaxation yields an optimal solution which is integral, thus solving the problem. Perfect, ideal and balanced matrices are three classes of constraint matrices with such integrality properties (for the set packing...

In the title compound, [CdCl(2)(C(5)H(7)N(3)O)(2)], the Cd(II) atom is six-coordinated by two heterocyclic N atoms [Cd-N = 2.261 (2) and 2.286 (2) Å] and two O atoms [Cd-O = 2.624 (2) and 2.692 (2) Å] from two bidentate chelate 2-amino-6-methyl-pyrimidin-4(1H)-one ligands and two chloride ions [Cd-Cl = 2.4674 (6) and 2.4893 (7) Å]. The crystal packing is characterized by an open-framework archi...

We present an efficient Monte Carlo method for the lattice sphere packing problem in d dimensions. We use this method to numerically discover de novo the densest lattice sphere packing in dimensions 9 through 20. Our method goes beyond previous methods, not only in exploring higher dimensions but also in shedding light on the statistical mechanics underlying the problem in question. We observe ...

injection molding is one of the most common processes which are used for manufacturing different plastic parts. this method includes 3 continuous steps: filling of the mold, cooling and driving the part out. a wide range of plastic and non-plastic materials can be used as raw material in this process. one of the most important advantages of this way of production is that it is very economic. in...

By pouring equal balls into a container one obtains disordered packings with fascinating properties which might shed light on several elusive properties of complex materials such as amorphous metals or colloids. In any real experiment with equal-sized spheres one cannot reach packing fractions (fraction of volume occupied by the spheres respect to the total volume, ρ) below the Random Loose Pac...

In the age of Big Data the problem of storing huge volume of data in a minimum storage space by utilizing available resources properly is an open problem and an important research aspect in recent days. This problem has a close relationship with the famous classical NP-Hard combinatorial optimization problem namely the “Bin Packing Problem” where bins represent available storage space and the p...

Each packing of R d by translates of the unit cube [0, 1) d admits a decomposition into at most two parts such that if a translate of the unit cube is covered by one of them, then it also belongs to such a part. Let I = [0, 1) d , and S ⊂ R d be a non-empty set. We say that the set I + S = {I + s : s ∈ S} is a packing of R d by (half-open) unit cubes if the members of I + S are pairwise disjoin...

We solve an open problem in the literature by providing an online algorithm for multidimensional bin packing that uses only bounded space. To achieve this, we introduce a new technique for classifying the items to be packed. We show that our algorithm is optimal among bounded space algorithms for any dimension d > 1. Its asymptotic performance ratio is (Π∞) , where Π∞ ≈ 1.691 is the asymptotic ...

INTRODUCTION Most surgical wounds are closed primarily, but some are allowed to heal by secondary intention. This usually involves repeated packing and dressing of the raw wound surfaces. Although the long-term care of such wounds has devolved to the care of nurses in the community or out-patient setting, the initial wound dressing or cavity packing is done by the surgeon in the operating theat...