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

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 $g$ destinations, our deterministic algorithm can achieve the capacity in $\left\lceil \log(g+1)\right\rceil$ uses of the network.Comment: 12 pages, 2 figures, submitted to CISS 201

Population structure of Ferosagitta ferox (Chaetognatha) in the northwest coastal waters of the Persian Gulf

Population dynamics of Ferosagitta ferox (Chaetognatha) was carried out in coastal waters of Khur-e-Mussa's Channel in Khuzestan Province, northwest Persian Gulf. Monthly samples were collected with 300km mesh size plankton net in oblique tow from near bottom to surface waters. In total, 7 species of Chaetognaths were identified belonging to 1 class (Sagittoidea), 1 order (Aphragmophora), 2 families (Sagittidae and Krohnittidae) and 4 genera (Aidanosagitta, Ferosagitta, Flaccisagitta and Krohnitta). The identified species included A. Bedford, A. neglecta, F. ferox, Flaccisagitta enflata, F. hexaptera, Krohnitta pacifica and one unknown species. Due to presence and excessive frequency of F. ferox in all samples, we focused on its population variation as an indicator of Chaetognatha. We determined length groups for adult individuals in 4-21mm range with 1mm increments. The year round presence of juvenile and small individuals showed the continuous reproduction of F. ferox with two considerable peaks in March and July. The evaluated recruitment indicated that the species has a low growth rate and a long life cycle

Seasonal change of thyroid histomorphological structure and hormone production in yellowfin seabream (Acanthopagrus latus) in the Persian Gulf

Seasonal changes of the thyroid gland structure and hormones secretion was examined in yellowfin seabream (Acanthopagrus latus) in the northwest of Persian Gulf (Musa creek). Thyroid gland composed of follicles scattered around the ventral aorta, near the gills. Follicular cells varied according to secretion of the gland during warm and cold seasons. Thyroid hormones (Triidothyronine [T3] and Thyroxine [T4]) were detected in the fish serum in levels ranged from 4.09-1.30 ng/mL for T3 and from 1.10-0.21 ng/mL for (T4) in the warm and cold seasons, respectively. The results showed that the height of thyroid epithelium and plasma concentration of thyroid hormones (thyroid activity) in A. latus increased significantly during spring and summer. The peak of these factors occurred in midsummer (August). Then, the thyroid activity decreased significantly during autumn and early winter from October to December according to decrease of temperature. T3 and T4 increased significantly from January to April

The effect of heavy metal on Chlorella vulgaris, Scenedesmus obliquus and Anabaena flos-aquae

In this survey two species of chlorophyta (Chlorella vulgaris and Scenedesmus obliquus) and one species of blue-green algae (Anabaena flos- aquae) were exposed with heavy metal (zinc) under lab condition (temp. 25±2°C, light 3500±350 lux) for 96 hours. After this time, these species were counted with hemocytometer and based on probit analysis method and was determined ECIO, EC50 and EC90. Amount of EC50 for C. vulgaris, S. obliquus and A. flos-aquae were 0.134,0.047 and 0.093 mg/lit, respectively and this subject was distincted that S obliquus has more endurance than other species. Max value of zinc for these species (C. vulgaris, S. obiquus and A. flos-aquae ) were 0.0134, 0.0047 and 0.0093 mg/l respectively. Regression coefficient was 92-98 percent between concentration logarithm of zinc and decrease of these species density

Genetic variation of Metapenaeus affinis in Persian Gulf coastal waters using microsatellite markers

Genetic diversity of Metapenaeus affinis population from the northern coasts of the Persian Gulf (Bahrakan, Lifeh-Boosiaf) was studies using microsatellite markers. During September to October 2007, 60 samples of pleopods tissue of the shrimp were taken and genomic DNA was extracted by acetate method. PCR was performed on microsatellite primers. To measure fragment size, samples were run on an 8% polyacrylamid gel. For each microsatellite locus, using genetic software, Pop Gene and Gene Alex, allele frequency, real and expected heterozygosity, Fst and Rst and other relevant factors were measured. Of the obtained 5 paired microsatellite primers, all were polymorphic. The mean observed and effective alleles number was 7 and 3.67, respectively and also the mean observed and expected heterozygosis was 0.27 and 0.66, respectively. It was also seen that specimens from all regions were not in HardyWeinberg Equibrium in all of the loci. Based on the analysis of molecular variance (AMOVA) Fst, Rst and Nm were 0.107, 0.372 and 2.092, respectively. The highest genetic distance was 0.571 and the lowest was 0.561. The present study showed that two different populations of Metapenaeus affinis are living in the Bahrakan and Lifeh-Boosiaf region northwest coasts of the Persian Gulf

A photovoltaic system using supercapacitor energy storage for power equilibrium and voltage stability

In a photovoltaic system, a stable voltage and of tolerable power equilibrium is needed. Hence, a dedicated analog charge controller for a storage system which controls energy flow to impose power equilibrium, and therefore, voltage stability on the load is required. We demonstrate here our successful design considerations employing supercapacitors as main energy storage as well as a buffer in a standalone photovoltaic system, incorporating a dedicated supercapacitor charge controller for the first time. Firstly, we demonstrated a photovoltaic system employing supercapacitors as main energy storage as well as a buffer in a standalone photovoltaic system. Secondly, we design a constant voltage maximum power point tracker (MPPT) for peak power extraction from the photovoltaic generator. Thirdly, we incorporated a supercapacitor charge controller for power equilibrium and voltage stability through a dedicated analog charge controller in our design, the first of its kind. Fourthly, we analyzed the use of supercapacitor storage to mitigate disequilibrium between power supply and demands, which, in turn, causes overvoltage or under voltage across the load. Lastly, we then went ahead to demonstrate the control of the energy flow in the system so as to maintain rated voltage across a variant demand load