An antimatroid is a family of sets which is accessible, closed under union, and includes an empty set. A number of examples of antimatroids arise from various kinds of shellings and searches on combinatorial objects, such as, edge=node shelling of trees, poset shelling, node-search on graphs, etc. (Discrete Math. 78 (1989) 223; Geom. Dedicata 19 (1985) 247; Greedoids, Springer, Berlin, 1980) [1...

Nitrogen is one of the most important factor affecting maize (Zea mays L.) yield and income of smallholders under semiarid climates. Field experiments were conducted to investigate the impact of different N-fertilizer sources [urea, calcium ammonium nitrate (CAN), and ammonium sulfate (AS)] and rates (50, 100, 150, and 200 kg ha-1) on umber of rows ear-1 (NOR ear-1), number of seeds row-1 (NOS ...

We discuss a simple model for tumor growth, which results in realistic tumor shapes. We present three variants of an algorithm for packing a three dimensional volume with a finite number of disjoint spherical volumes, of given diameters. We apply our algorithm to packing spherical shots into tumors that we have generated, and analyze the effectiveness of the algorithm in filling the tumor volum...

Received 5/9/2012 Accepted 28/3/2013 (005675) 1 Faculty of Pharmaceutical Sciences, Federal University of Amazonas – UFAM, Rua Comendador Alexandre Amorim, 330, Bairro Aparecida, CEP 69010-300, Manaus, AM, Brazil, e-mail: [email protected] *Corresponding author Brazil nut sorting for aflatoxin prevention: a comparison between automatic and manual shelling methods Ariane Mendonça PACHECO1, Ma...

The comparative study in the development of peanut shelling machines is presented. Peanut constitutes a significant part processing. Researchers had developed different type machines, addressing problem groundnut. Some authors modified past to improve efficiency and get best possible output. This presents trends these performance evaluation, merits, demerits. A look at factors affecting operati...