153 research outputs found

    A Deterministic Polynomial--Time Algorithm for Constructing a Multicast Coding Scheme for Linear Deterministic Relay Networks

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    We propose a new way to construct a multicast coding scheme for linear deterministic relay networks. Our construction can be regarded as a generalization of the well-known multicast network coding scheme of Jaggi et al. to linear deterministic relay networks and is based on the notion of flow for a unicast session that was introduced by the authors in earlier work. We present randomized and deterministic polynomial--time versions of our algorithm and show that for a network with gg destinations, our deterministic algorithm can achieve the capacity in log(g+1)\left\lceil \log(g+1)\right\rceil uses of the network.Comment: 12 pages, 2 figures, submitted to CISS 201

    Factors affecting phytoplankton fluctuations in the Persian Gulf (Bushehr coastal waters) during winter and spring 2012 - 2013

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    In this study, surface water samples were collected monthly from five stations inclduing Nayband Bay, Assaloye, Dayer, Kabgan and Bushehr from December 2012 to June 2013. Sampling stations were chosen according to data being collected during algal bloom caused by Cochlodinium polykrikoides in 2008. A total of 45 genera of phytoplankton belongs to four classes were totally identified accounting for 53 species of Bacilariophyceae, 32 species of Dinophyceae, one genus of Euglenophyceae, and one genus of Cyanophyceae. Bacilariophyceae with 89.5% was the most abundant family followed by Dinophyceae with 9.03%, Cyanophyceae with 1.25 % and Euglenophyceae with 0.22 %, respectively. The highest phytoplankton abundance was observed in Bushehr and Nayband Bay stations. In addition to statistical tests, Shannon (Shanon-Winner) and dominance indices were investigated. The lowest variability for Shannon index (1.90) was recorded in Bushehr Station in comparison with other stations. The highest Shanon index was in Dayer station (2.90) with the increase of diversity in Dinophyceae. Evidence of coastal pollution in Dayer along with nutrient inputs from land might be effective in increasing the Shannon index. At 80-90% simmilarity, the results of Cluster analysis separated Dayer station from other stations. It seems that a part of uniformity in phytoplankton abundance is affected by the mild conditions of ambient temperature. The total diversity of phytoplankton in the study area was low. The relative moderation of temperature seems to have contributed to the dominance of diatoms. Yet, the increased volume dust (as emerged by the increased dusty days per year) and the introduction of its accumulation in the Persian Gulf waters, along with other pollutants on phytoplankton communities might be underlaying factors for the dominace of diatoms in the study area

    Fecundity of Otolithes ruber (Scneider, 1801) in Khuzestan coastal waters

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    To study on fecundity of O. ruber, in spawning season, 31 samples caught in Khouzestan waters on Feb. 1996 to April 1997 were examined, and gravimetry method was used. Maximum absolute fecundity were 1483369 ± 14409 and 81726± 1831 eggs respectively, and relative fecundity 1107 ± 10.6 and 256±5.5 per gram body weight, respectively. The highest correlation coefficient was observed in absolute fecundity with gonadal weight (G W) and relative fecundity with gonadosomatic index (GSI). Also absolute and relative fecundity had the highest multiple regression coefficient with gonadosomatic index (GSI), gutted weight (GU) and standard length (SL)

    Feeding of tiger tooth croaker (Otolithes ruber) in Khuzestan coastal waters

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    In order to study on feeding of O. ruber, sampling was carried out monthly from Nov. 96 to Aug. 97, stomach contents of 691 samples were examined of which, 67% were empty and 33% had feed residues.Index of being vacant was higher in males in comparison with females, this index reaches at maximum from Feb. to May for males and in Aug. and Jan. for females. Fish was found in 58% of the stomach, shrimp in 39% and fish and shrimp in 3% of them. During a year feeding intensity did not show a regular pattern and it was weak. Relative importance index for fish and shrimp was 63% and 37% respectively. The main food of immature fish was shrimp, which as they grow shrimp replaced by fish as the main food, so O. ruber is a carnivorous and hunter species
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