Flow properties of driven-diffusive lattice gases: theory and computer simulation

We develop n-cluster mean-field theories (0 < n < 5) for calculating the flow properties of the non-equilibrium steady-states of the Katz-Lebowitz-Spohn model of the driven diffusive lattice gas, with attractive and repulsive inter-particle interactions, in both one and two dimensions for arbitrary particle densities, temperature as well as the driving field. We compare our theoretical results with the corresponding numerical data we have obtained from the computer simulations to demonstrate the level of accuracy of our theoretical predictions. We also compare our results with those for some other prototype models, notably particle-hopping models of vehicular traffic, to demonstrate the novel qualitative features we have observed in the Katz-Lebowitz-Spohn model, emphasizing, in particular, the consequences of repulsive inter-particle interactions.Comment: 12 RevTex page

Abortive replication of choleraphage Φ 149 in Vibrio cholerae biotype El Tor

Choleraphage Φ 149 adsorbed irreversibly to Vibrio cholerae biotype el tor cells, and 50% of the injected phage DNA bound to the cell membrane. Although no infectious centers were produced at any time during infection, the host macromolecular syntheses were shut off and the host DNA underwent chloramphenicol-inhibitable degradation. Synthesis of monomeric phage DNA continued similar to that observed in the permissive host. However, the concatemeric DNA intermediates produced were unstable and could not be chased to mature phage DNA. Pulse-labeling of UV-irradiated infected cells at different times during infection allowed identification of phage-specific proteins made in this nonpermissive host. Although most of the early proteins were made, only some of the late proteins were transiently synthesized

Collective traffic-like movement of ants on a trail: dynamical phases and phase transitions

The traffic-like collective movement of ants on a trail can be described by a stochastic cellular automaton model. We have earlier investigated its unusual flow-density relation by using various mean field approximations and computer simulations. In this paper, we study the model following an alternative approach based on the analogy with the zero range process, which is one of the few known exactly solvable stochastic dynamical models. We show that our theory can quantitatively account for the unusual non-monotonic dependence of the average speed of the ants on their density for finite lattices with periodic boundary conditions. Moreover, we argue that the model exhibits a continuous phase transition at the critial density only in a limiting case. Furthermore, we investigate the phase diagram of the model by replacing the periodic boundary conditions by open boundary conditions.Comment: 8 pages, 6 figure

Productivity, Energy Use Efficiency and Economics of Organic Scented Rice Cultivation in Sub-Humid Agroecosystem

The increasing demand for organic cereals especially indigenous scented rice varieties in the recent years has peaked farmers’ interest towards its organic production. However, the threat of crop loss under organic cultivation has been holding back large scale initiatives. Inhana Rational Farming (IRF) Technology has come up as a promising organic package of practice towards mitigating this drawback of organic production that too at an affordable economics. The present study was conducted to generate scientific information regarding organic scented rice cultivation (Oryza sativa var. ‘Gobindobhog’) utilizing this organic POP in terms of productivity, energy use efficiency and economics. The yield of scented rice cultivated using organic POP was found to be 18% higher than the conventionally grown ones. In terms of energy use efficiency as well, organic POP was calculated to be more efficient signifying the role of organic practice in sustainable agriculture. Net profitability of organic paddy increased up to 17% with a minimum premium price of 25%. This increased higher income opportunity from same unit of land was an added benefit apart from improved soil quality in general; under organic management

Optimizing Traffic Lights in a Cellular Automaton Model for City Traffic

We study the impact of global traffic light control strategies in a recently proposed cellular automaton model for vehicular traffic in city networks. The model combines basic ideas of the Biham-Middleton-Levine model for city traffic and the Nagel-Schreckenberg model for highway traffic. The city network has a simple square lattice geometry. All streets and intersections are treated equally, i.e., there are no dominant streets. Starting from a simple synchronized strategy we show that the capacity of the network strongly depends on the cycle times of the traffic lights. Moreover we point out that the optimal time periods are determined by the geometric characteristics of the network, i.e., the distance between the intersections. In the case of synchronized traffic lights the derivation of the optimal cycle times in the network can be reduced to a simpler problem, the flow optimization of a single street with one traffic light operating as a bottleneck. In order to obtain an enhanced throughput in the model improved global strategies are tested, e.g., green wave and random switching strategies, which lead to surprising results.Comment: 13 pages, 10 figure

Determinants of male participation in reproductive healthcare services: a cross-sectional study

Background The role of male’s participation in reproductive healthcare is now well-recognized. The present study investigated the role of men in some selected reproductive health issues, characterizing their involvement, including factors influencing their participation in reproductive healthcare services. Methods This study was conducted in the working areas of urban and rural implemented by NGOs. The sample-size was determined scientifically. The systematic sampling procedure was used for selecting the sample. The study included 615 men aged 25-45 years. Bivariate analysis was performed between male’s involvement as the dependent variable with several independent variables. Logistic regression analysis was applied to assess the effects of risk factors on the participation of men in reproductive health care services. Results The mean age of the respondents was little over 34 years while their mean years of schooling was 3.7, and their mean monthly income was about Tk 3,400 (US$ 1 = Tk 70) at the time of the study. Rickshaw-pulling and driving was the main occupation of the respondents from the urban while farming were main occupation in the rural area respectively. About two-thirds of the respondents discussed reproductive health issues with their wives and accompanied them to healthcare facilities. The current contraceptive-use rate was 63% among the men who attended the evening clinics. Results of bivariate analysis showed a significant association with education, occupation, income, access to media, and number of living children. Results of logistic regression analysis showed that secondary to higher education level, number of living children, paid employment status, long marital duration, and access to media were important correlates of males’ involvement in reproductive healthcare services. Conclusions The results imply that a greater integration of reproductive healthcare matters with the Millennium Development Goals and increasing perception of men through enrollment in various components of reproductive activities will produce synergistic effects

Cluster formation and anomalous fundamental diagram in an ant trail model

A recently proposed stochastic cellular automaton model ({\it J. Phys. A 35, L573 (2002)}), motivated by the motions of ants in a trail, is investigated in detail in this paper. The flux of ants in this model is sensitive to the probability of evaporation of pheromone, and the average speed of the ants varies non-monotonically with their density. This remarkable property is analyzed here using phenomenological and microscopic approximations thereby elucidating the nature of the spatio-temporal organization of the ants. We find that the observations can be understood by the formation of loose clusters, i.e. space regions of enhanced, but not maximal, density.Comment: 11 pages, REVTEX, with 11 embedded EPS file

Effect of chitosan and acetic acid on the shelf life of sea bass fillets stored at refrigerated temperature

Considering the necessity on the use of chitosan and acetic acid as an antimicrobial and antioxidant agents, an attempt was made to study their effect on Asian sea bass fillets stored at refrigerated temperature of 4±1°C. The effectiveness of different antimicrobials (Chitosan and Acetic acid) were measured by disk diffusion method against five bacterial strains (E. coli, Vibrio parahaemolyticus, Staphylococcus aureus, Proteus mirabilis and Pseudomonas fragi) with 1% Acetic acid as (T1), 1% Acetic acid + 1% Chitosan as (T2), 1% Acetic acid + 2% Chi-tosan as (T3) and distilled water as control (C).T2 was more effective in inhibiting all the bacteria except Pseudomo-nas fragi. Treatment T1 was found to be more effective against it whereas the action of T3 on the bacterial strains was also effective but less than the other two treatments. Further, antioxidant property of the treatments were measured by DPPH method which indicated that T3 showed highest % of antioxidative activity (3.94%) followed by T1 (3.85%), T2 (2.62%), and C (1.788%).Thus, it is observed that the antioxidant activity was found to be increased with the increasing concentration of chitosan. Application of chitosan and acetic acid coatings on Asian sea bass ( Lates calcarifer) fillets successfully controlled the TVB-N values, PV and TBA values (p&lt;0.05) when compared to control sample and among all the treatments T2 was found to be the best. Coating of chitosan and acetic acid on the fillets also resulted in improvement of sensory scores as well as acceptability under refrigerated condition