Structural Routability of n-Pairs Information Networks

Information does not generally behave like a conservative fluid flow in communication networks with multiple sources and sinks. However, it is often conceptually and practically useful to be able to associate separate data streams with each source-sink pair, with only routing and no coding performed at the network nodes. This raises the question of whether there is a nontrivial class of network topologies for which achievability is always equivalent to routability, for any combination of source signals and positive channel capacities. This chapter considers possibly cyclic, directed, errorless networks with n source-sink pairs and mutually independent source signals. The concept of downward dominance is introduced and it is shown that, if the network topology is downward dominated, then the achievability of a given combination of source signals and channel capacities implies the existence of a feasible multicommodity flow.Comment: The final publication is available at link.springer.com http://link.springer.com/chapter/10.1007/978-3-319-02150-8_

Length frequency data from monthly catches of Pickhandle barracuda, Sphyraena jello, were studied during one year in coastal waters of Bushehr Province (Persian Gulf)

A total of 311 specimens were collected from November 2006 to October 2007. We estimated Population parameters from length frequency data. These cases consist of the von Bertalanffy growth parameters and mortality, as well as exploitation rate. The result indicated that pickhandle barracuda had L_∞ =109.21 cm total length, K=0.37 and theoretical age at zero length, = -0.5 The total mortality rate (Z) was estimated to be 1.91, the fishing mortality rate (F) and the natural mortality(M) were 1.30 and 0.61, respectively. The exploitation rate (E) was 0.68. The exploitation rate indicated that the stockis in high pressure of catch and overexploited

Artificial Sequences and Complexity Measures

In this paper we exploit concepts of information theory to address the fundamental problem of identifying and defining the most suitable tools to extract, in a automatic and agnostic way, information from a generic string of characters. We introduce in particular a class of methods which use in a crucial way data compression techniques in order to define a measure of remoteness and distance between pairs of sequences of characters (e.g. texts) based on their relative information content. We also discuss in detail how specific features of data compression techniques could be used to introduce the notion of dictionary of a given sequence and of Artificial Text and we show how these new tools can be used for information extraction purposes. We point out the versatility and generality of our method that applies to any kind of corpora of character strings independently of the type of coding behind them. We consider as a case study linguistic motivated problems and we present results for automatic language recognition, authorship attribution and self consistent-classification.Comment: Revised version, with major changes, of previous "Data Compression approach to Information Extraction and Classification" by A. Baronchelli and V. Loreto. 15 pages; 5 figure

Reproduction and feeding biology of madagascar meager (Argyrosomus hololepidotus) from Khuzestan coastal waters

Biological attributes of Madagascar Meager (Argyrosomus hololepidotus) was studied from October 2008 to September 2009 in coastal waters of Khuzestan province. Average maximum length was 128.4±7.50 in October and average minimum length was 104.86±12.47 in May. The maximum weight was 27500g, the minimum weight was 5700g and mean weight for males and females were 15.222±4.40 and 16.942±5.09, respectively. Reproductive studies showed that peak maturity season occurred in July. The length­ weight relationship were calculated as W=0.042L 2 70 for males and W=0.06L2 61for females. The male-female sex ratio was calculated as 1:1.07 and chi-square analysis showed no significant difference (P>0.05) between the two sexes. The average absolute and relative fecundity were estimated to be 4054045±37265 and 179.19±50.41, respectively Madagascar Meager is carnivore and we found the diet of the species consisted of fish (75%), crustaceans (20%) and mollusks (5%). Analysis of monthly variation in the condition factor (CF) indicated a fluctuation throughout the year, with a high level during May. Vacuity index indicated a higher feeding rate in males compared to females. We also found that the species continues feeding in the spawning season

The Metabolic Consequences of Hepatic AMP-Kinase Phosphorylation in Rainbow Trout

AMP-activated protein kinase (AMPK), a phylogenetically conserved serine/threonine protein kinase, is proposed to function as a “fuel gauge” to monitor cellular energy status in response to nutritional environmental variations. However, in fish, few studies have addressed the metabolic consequences related to the activation of this kinase. This study demonstrates that the rainbow trout (Oncorhynchus mykiss) possesses paralogs of the three known AMPK subunits that co-diversified, that the AMPK protein is present in the liver and in isolated hepatocytes, and it does change in response to physiological (fasting-re-feeding cycle) and pharmacological (AICAR and metformin administration and incubations) manipulations. Moreover, the phosphorylation of AMPK results in the phosphorylation of acetyl-CoA carboxylase, a main downstream target of AMPK in mammals. Other findings include changes in hepatic glycogen levels and several molecular actors involved in hepatic glucose and lipid metabolism, including mRNA transcript levels for glucokinase, glucose-6-phosphatase and fatty acid synthase both in vivo and in vitro. The fact that most results presented in this study are consistent with the recognized role of AMPK as a master regulator of energy homeostasis in living organisms supports the idea that these functions are conserved in this piscine model

Edge-Cut Bounds on Network Coding Rates

Active networks are network architectures with processors that are capable of executing code carried by the packets passing through them. A critical network management concern is the optimization of such networks and tight bounds on their performance serve as useful design benchmarks. A new bound on communication rates is developed that applies to network coding, which is a promising active network application that has processors transmit packets that are general functions, for example a bit-wise XOR, of selected received packets. The bound generalizes an edge-cut bound on routing rates by progressively removing edges from the network graph and checking whether certain strengthened d -separation conditions are satisfied. The bound improves on the cut-set bound and its efficacy is demonstrated by showing that routing is rate-optimal for some commonly cited examples in the networking literature.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43451/1/10922_2005_Article_9019.pd

Full-Length Hepatitis B Virus Core Protein Packages Viral and Heterologous RNA with Similarly High Levels of Cooperativity▿

A critical feature of a viral life cycle is the ability to selectively package the viral genome. In vivo, phosphorylated hepatitis B virus (HBV) core protein specifically encapsidates a complex of pregenomic RNA (pgRNA) and viral polymerase; it has been suggested that packaging is specific for the complex. Here, we test the hypothesis that core protein has intrinsic specificity for pgRNA, independent of the polymerase. For these studies, we also evaluated the effect of core protein phosphorylation on assembly and RNA binding, using phosphorylated core protein and a phosphorylation mimic in which S155, S162, and S170 were mutated to glutamic acid. We have developed an in vitro system where capsids are disassembled and assembly-active core protein dimer is purified. With this protein, we have reassembled empty capsids and RNA-filled capsids. We found that core protein dimer bound and encapsidated both the HBV pregenomic RNA and heterologous RNA with high levels of cooperativity, irrespective of phosphorylation. In direct competition assays, no specificity for pregenomic RNA was observed. This suggests that another factor, such as the viral polymerase, is required for specific packaging. These results also beg the question of what prevents HBV core protein from assembling on nonviral RNA, preserving the protein for virus production