Seroprevalence of anti-Hp and anti-cagA antibodies among healthy persons in Golestan province, northeast of Iran (2010)

Background: The major cause of peptic ulcer disease is helicobacter pylori (Hp), and it is also implicated in the pathogenesis of adenocarcinoma of the distal stomach and gastric lymphoma. The incidence of peptic ulcer disease, atrophic gastritis, and gastric adenocarcinoma are more common in people infected of cagA positive strains of Hp. The aim of this study was to determine the prevalence of the anti-Hp and anti-cagA antibodies among healthy persons in Golestan province-North of Iran. Methods: The blood samples of 1028 healthy people were collected all over Golestan province by cluster sampling. A demographic questionnaire was completed and body mass index (BMI) was calculated for each case. Hp-IgG (Pishtaz teb Co. Iran) and anti- cagA (DIA.PRO Italy) titer were evaluated by Elisa method. Data were collected and analyzed. Results: Six hundred-eighty three individuals (66.4%) were positive for Hp and 395 (57.8%) of them were cagA positive. Hp positive cases were (66.3%) and (66.6%) in male and female, respectively. Prevalence of cagA was 56.3% and 58.9%, respectively. The most seropositivity of Helicobacter Pylori (75.4%) was in 55-64 years old (p<0.001). Prevalence of cagA (63.4%) was more in age between 15-24 years. Conclusion: Prevalence of anti-Hp antibody and strains of cagA seropositive in healthy persons of this province of Iran were relatively high. Preventive protocol for reducing of the infection is recommended

The Approximate Capacity Region of the Gaussian Z-Interference Channel with Conferencing Encoders

A two-user Gaussian Z-Interference Channel (GZIC) is considered, in which encoders are connected through noiseless links with finite capacities. In this setting, prior to each transmission block the encoders communicate with each other over the cooperative links. The capacity region and the sum-capacity of the channel are characterized within 1.71 bits per user and 2 bits in total, respectively. It is also established that properly sharing the total limited cooperation capacity between the cooperative links may enhance the achievable region, even when compared to the case of unidirectional transmitter cooperation with infinite cooperation capacity. To obtain the results, genie-aided upper bounds on the sum-capacity and cut-set bounds on the individual rates are compared with the achievable rate region. In the interference-limited regime, the achievable scheme enjoys a simple type of Han-Kobayashi signaling, together with the zero-forcing, and basic relaying techniques. In the noise-limited regime, it is shown that treating interference as noise achieves the capacity region up to a single bit per user.Comment: 25 pages, 6 figures, submitted to IEEE Transactions on Information Theor

Secondary threshold amplitudes for sinuous streak breakdown

The nonlinear stability of laminar sinuously bent streaks is studied for the plane Couette flow at Re=500 in a nearly minimal box and for the Blasius boundary layer at Re_d*= 700. The initial perturbations are nonlinearly saturated streamwise streaks of amplitude AU perturbed with sinuous perturbations of amplitude AW. The local boundary of the basin of attraction of the linearly stable laminar flow is computed by bisection and projected in the AU – AW plane providing a well defined critical curve. Different streak transition scenarios are seen to correspond to different regions of the critical curve. The modal instability of the streaks is responsible for transition for AU ~ 25%–27% for the considered flows, where sinuous perturbations of amplitude below AW ~ 1%–2% are sufficient to counteract the streak viscous dissipation and induce breakdown. The critical amplitude of the sinuous perturbations increases when the streamwise streak amplitude is decreased. With secondary perturbations amplitude AW ~ 4%, breakdown is induced on stable streamwise streaks with AU ~ 13%, following the secondary transient growth scenario first examined by Schoppa and Hussain [J. Fluid Mech. 453, 57 (2002)]. A cross-over, where the critical amplitude of the sinuous perturbation becomes larger than the amplitude of streamwise streaks, is observed for streaks of small amplitude AU < 5%–6%. In this case, the transition is induced by an initial transient amplification of streamwise vortices, forced by the decaying sinuous mode. This is followed by the growth of the streaks and final breakdown. The shape of the critical AU – AW curve is very similar for Couette and boundary layer flows and seems to be relatively insensitive to the nature of the edge states on the basin boundary. The shape of this critical curve indicates that the stability of streamwise streaks should always be assessed in terms of both the streak amplitude and the amplitude of spanwise velocity perturbations

FARS: Fuzzy Ant based Recommender System for Web Users

Recommender systems are useful tools which provide an adaptive web environment for web users. Nowadays, having a user friendly website is a big challenge in e-commerce technology. In this paper, applying the benefits of both collaborative and content based filtering techniques is proposed by presenting a fuzzy recommender system based on collaborative behavior of ants (FARS). FARS works in two phases: modeling and recommendation. First, user’s behaviors are modeled offline and the results are used in second phase for online recommendation. Fuzzy techniques provide the possibility of capturing uncertainty among user interests and ant based algorithms provides us with optimal solutions. The performance of FARS is evaluated using log files of “Information and Communication Technology Center” of Isfahan municipality in Iran and compared with ant based recommender system (ARS). The results shown are promising and proved that integrating fuzzy Ant approach provides us with more functional and robust recommendations

Stability of a jet in crossflow

We have produced a fluid dynamics video with data from Direct Numerical Simulation (DNS) of a jet in crossflow at several low values of the velocity inflow ratio R. We show that, as the velocity ratio R increases, the flow evolves from simple periodic vortex shedding (a limit cycle) to more complicated quasi-periodic behavior, before finally exhibiting asymmetric chaotic motion. We also perform a stability analysis just above the first bifurcation, where R is the bifurcation parameter. Using the overlap of the direct and the adjoint eigenmodes, we confirm that the first instability arises in the shear layer downstream of the jet orifice on the boundary of the backflow region just behind the jet.Comment: Two fluid dynamics videos, high-resolution 1024x768 (~80MB), and low resolution 320x240 (~10MB), included in the ancillary file

Checklist of phytoplankton taxa in the Iranian waters of the Caspian Sea

Phytoplankton taxa composition of the Caspian Sea were evaluated by using samples collected at 12 stations along the Iranian coast of the Caspian Sea between 1996 and 2010. This study identified 158 phytoplankton species consisted of diatoms (70 species), dinoflagellates (23 species), chlorophytes (29 species), cyanophytes (31 species), and euglenoids (5 species). The dominant species were the diatoms Thalassionema nitzschioides, Dactyliosolen fragilissimus, the dinoflagellate Prorocentrum cordatum, and the cyanophyte of genus Oscillatoria. The average species diversity index of phytoplankton community was 1.88 as recorded in this study. There were main changes in phytoplankton composition as compared with previous study. It could be related to the severe human activities and difference in sampling strategies

Distribution pattern and biomass estimation of benthic invertebrates in Aras reservoir

This study was carried out at monthly basis covering six sampling stations in Aras reservoir in 1995, The samples were collected by Ekman grab with 3 replicates, The results Showed that Oligochaetes were the dominant taxa in this reservoir which were observed all year round and had the highest abundance and biomass, The Chironomidae were the second dominant family. Gammaridae and Mysidae had the least abundance and biomass, Maximum biomass of Oligochaetes was observed in spring with the average figure of 19.03 g/m2 and minimum biomass was observed in winter with average biomass of 5.87 g/m2 Maximum and minimum biomass or Chironomidae were recorded in summer and spring, of which their correspond average biomass were 1.52 and 0.06 g/m2, respectively. The highest and lowest biomass of Mysidae family were observed in summer and spring with the average biomass of 0.46 and 0.00 g/m2, respectively. Gammaridae family observed only in summer. The differences of biomass of these 3 families were significant based on kruskal-wallis nonparametric test (p0.05). Maximum (26.06 g/m2) and minimum biomass (3.14 g/m2) of benthic organisms were observed in stations 4 and 5, respectively and no remarkable variation was observed in the percentage of total organic matter (TOM) content during different seasons. Maximum and minimum average percentage of TOM were 6.66% to 4.79% in spring and winter, respectively. Based on collected data and obtained results, it can be assumed that feeding of fishes, sediment composition, amount of TOM and water temperature were the most important factors effect on temporal and spatial variation in population and biomass of benthic organisms of Aras reservoir