A parallel algorithm for diffusion-limited aggregation (DLA) is described and analyzed from the perspective of computational complexity. The dynamic exponent z of the algorithm is defined with respect to the probabilistic parallel random-access machine (PRAM) model of parallel computation according to T ∼ L z , where L is the cluster size, T is the running time, and the algorithm uses a number ...

There is a variety of methods for ranking objectives in multiobjective optimization and some are difficult to define because they require information a priori (e.g. establishing weights in a weighted approach or setting the ordering in a lexicographic approach). In manyobjective optimization problems, those methods may exhibit poor diversification and intensification performance. We propose the...

We investigate some basic properties of Damped Lyman alpha systems based on the Semi-Analytical model of disk galaxy formation theory. We derive the DLA metallicity, column density, number density, gas content and cosmic star formation rate by assuming that disks form at the center of dark halos, and the modelled DLAs are selected by Monte Carlo simulation according to the distributions of halo...

According to Pei, Fall & Hauser (1999), the global metallicity evolution of the Universe can be represented by the ratio of the total metal content to the total gas content measured in Damped Lyman–α (DLA) systems (the “column density weighted metallicity” à la Pettini). To minimize dust obscuration effects, a DLA sample with negligible dust content is considered, namely, 50 DLAs with logNHI < ...

We present the results of a survey of GRB afterglows and DLA absorption line systems, in which we compare the abundances of elements from the absorbers with surveys of stars, and previous work. Our results detect high metallicity systems within GRB afterglow absorption, consistent with galactic disks having high rates of star formation and enrichment of heavy elements. We also detect some of th...

T. asthmatica, which belongs to the family Asclepiadaceae is a small twining a plant with long fleshy roots. The plant shows broad activity against EA and DLA cells. The intraperitoneal injection of PE extract obtained from the powdered entire plant material to the tumor cell transplanted animals arrests the tumor growth and prevents the formation of the tumor. A significant increase in the lif...

The number of damped Ly absorbers (DLAs) currently known is about 100, but our knowledge of their sizes and morphologies is still very sparse as very few have been detected in emission. Here we present narrow{band and broad{band observations of a DLA in the eld of the quasar pair Q0151+048A (qA) and Q0151+048B (qB). These two quasars have very similar redshifts z em =1.922, 1.937, respectively,...

Chemoprevention, which includes the use of synthetic or natural agents (alone or in combination) to block the development of cancer in human beings, is an extremely promising strategy for cancer prevention. Apium graveolens seeds have been assessed for chemopreventive activity. The antiproliferative effect of the methanolic extract of Apium graveolens was evaluated in vitro on two human cell li...