Performance analysis of a scheme for concurrency/synchronization using queueing network models

Queueing network models have been used extensively to analyze performance of computer systems. However, queueing network models with product form solutions are not directly applicable to systems that process programs with internal concurrency/synchronization. An exact solution of such systems is often not feasible because of its large state space.Approximation techniques, based on queueing network theory, are presented which analyze the performance of closed systems with a specific scheme of concurrency/synchronization. The techniques are applicable to multitasking systems, distributed database systems, packet routing environments, and fork/join situations.This research was partially supported by CNPq/Brazil, Hospital Corporation of America (HCA) and Northern Telecom.     

Genetic and physical localization of the acetyl-coenzyme A synthetase gene ACS1 on chromosome I of Saccharomyces cerevisiae

The ACS1 gene, encoding acetyl-coenzyme A synthetase, was mapped genetically at the left arm of chromosome I between pURA3 and PYK1 at 19 and 28 cM respectively. Comparison with the physical map defined a recombinational ‘hot-spot’ in this region in addition to the one between CDC24 and PYK1.     

A reverse engineering approach for automatic annotation of Web pages

The Semantic Web is gaining increasing interest to fulfill the need of sharing, retrieving, and reusing information. Since Web pages are designed to be read by people, not machines, searching and reusing information on the Web is a difficult task without human participation. To this aim adding semantics (i.e meaning) to a Web page would help the machines to understand Web contents and better support the Web search process. One of the latest developments in this field is Google’s Rich Snippets, a service for Web site owners to add semantics to their Web pages. In this paper we provide a structured approach to automatically annotate a Web page with Rich Snippets RDFa tags. Exploiting a data reverse engineering method, combined with several heuristics, and a named entity recognition technique, our method is capable of recognizing and annotating a subset of Rich Snippets’ vocabulary, i.e., all the attributes of its Review concept, and the names of the Person and Organization concepts. We implemented tools and services and evaluated the accuracy of the approach on real E-commerce Web sites.     

Mapping multiple gas/odor sources in an uncontrolled indoor environment using a Bayesian occupancy grid mapping based method

In this paper we address the problem of autonomously localizing multiple gas/odor sources in an indoor environment without a strong airflow. To do this, a robot iteratively creates an occupancy grid map. The produced map shows the probability each discrete cell contains a source. Our approach is based on a recent adaptation (Jakuba, 2007) [16] to traditional Bayesian occupancy grid mapping for chemical source localization problems. The approach is less sensitive, in the considered scenario, to the choice of the algorithm parameters. We present experimental results with a robot in an indoor uncontrolled corridor in the presence of different ejecting sources proving the method is able to build reliable maps quickly (5.5 minutes in a 6 m×2.1 m area) and in real time.     

Comparative study of the consumption of virgin olive oil or seje on lipid profile and oxidation resistance of high density lipoprotein (HDL) of rat plasma

We compared the effect of the consumption of seje oil (Oenocarpus bataua), with that of olive oil, on plasma lipids and susceptibility in vitro to oxidation of high density lipoprotein (HDL) in the rat. Two groups often male Sprague Dawley rats were fed ad libitum, for a lapse of eight week, with a purified diets with 10g de seje oil or olive oil/100 g of diet (GS y GO respectively). The animals were exsanguinated at the end of the experimental after a 14 hour fast. Plasma was isolated by centrifugation, and the fractions of lipoproteins were separated from the plasma by sequential ultracentrifugation. Rats of GO had a statistically significant lower in concentration of TG (p < 0.05) compared with GS group. HDL fractions in both groups were oxidatively modified by incubation with copper ions. Differences in the fractions susceptibilities to peroxidation were studied by measuring the formation of thiobarbituric acid reactive substance (TBARS) for 3 hours. HDL in GS had a statistically significant decrease in TBARS formation (p < 0.05) relative to HDL of GO. This may be explained by the lower concentration of polyunsaturated fatty acids of HDL in GS compared with HDL in GO.     

Physicochemical,thermal, and pasting properties of flours and starches of eight Brazilian maize landraces (Zea mays L.)

Both genetic and environmental factors create significant variation in the amount and quality of maize landrace constituents. Details on the flours and starch characteristics have not been fully investigated. The physicochemical, pasting and thermal properties of 8 promising cultivars were assessed in this study and those properties were correlated. Higher values of swelling and solubility (RJ – 13.14%; 14.39%), lipid content (MG – 5.53%), WBC (PR – 18.89%), and amylose content (PR – 27.43%) were found for those genotypes. Lower onset temperatures of gelatinization (To) were observed for RX-F1 (66.1 °C) as RX-F1 (68.7 °C) genotype showed the lower pasting temperatures. A wide range of viscosity values was found among the maize landraces (MG-F0, 343 mPa s and RJ-F1, 175 mPa s) as well as for the retrogradation (R8C-F1, 796 mPa s and RX-F1, 22 mPa s). ATR-FTIR spectroscopy revealed amylose, amylopectin, lipids, and proteins as major flours constituents and their differences were discriminated by PCA analysis.     

Development of a multiplex PCR for rapid detection of verocytotoxin-producing Escherichia coli O26 in raw milk and ground beef

Verocytotoxin-producing Escherichia coli (VTEC) O26 is an emergent pathotype that has caused an increasing number of sporadic cases and outbreaks of gastroenteritis, hemorrhagic colitis, and hemolytic uremic syndrome in the United States and Europe. Many cases are associated with the consumption of milk and undercooked or fermented meats. The stx(2) strains of VTEC O26 seem to be more likely to cause human infections than isolates expressing only stx(1). The isolation and identification of VTEC O26 from foods is labor intensive and time-consuming. We developed a multiplex PCR (M-PCR) assay for the identification and characterization of E. coli O26 VTEC and its detection in raw milk and ground beef. The method is based on the amplification of the wzx, stx(1), and stx(2) genes for the simultaneous detection of the O26 antigen and verocytotoxin types 1 and 2. This M-PCR assay had a sensitivity of 10(8) CFU/ml when applied to a bacterial suspension and of 10(6) CFU/ml or g when applied to both inoculated milk and minced beef samples. This M-PCR assay also was highly specific, and results were consistently negative for negative controls (nonpathogenic E. coli strains, uninoculated milk and beef samples, and samples inoculated with the nontarget microorganisms). This method could be used for the rapid detection of E. coli O26 VTEC from foods and for the rapid identification and characterization of clinical and environmental isolates.     

Structural Investigations on the Anti‐HIV G‐Quadruplex‐Forming Oligonucleotide TGGGAG and Its Analogues: Evidence for the Presence of an A‐Tetrad

Several anti‐HIV aptamers adopt DNA quadruplex structures. Among these, “Hotoda's aptamer” (base sequence TGGGAG) was one of the first to be discovered. Although it has been the topic of some recent research, no detailed structural investigations have been reported. Here we report structural investigations on this aptamer and analogues with related sequences, by using UV, CD, and NMR spectroscopy as well as electrophoretic techniques. The addition of a 3′‐end thymine has allowed us to obtain a single, investigable quadruplex structure. Data clearly point to the presence of an A‐tetrad. Furthermore, the effects of the incorporation of an 8‐methyl‐2′‐deoxyguanosine at the 5′‐end of the G‐run were investigated.