Can one identify non-equilibrium in a three-state system by analyzing two-state trajectories?

For a three-state Markov system in a stationary state, we discuss whether, on the basis of data obtained from effective two-state (or on-off) trajectories, it is possible to discriminate between an equilibrium state and a non-equilibrium steady state. By calculating the full phase diagram we identify a large region where such data will be consistent only with non-equilibrium conditions. This regime is considerably larger than the region with oscillatory relaxation, which has previously been identified as a sufficient criterion for non-equilibrium.Comment: 4 pages, 2 figures, J. Chem. Phys. (2010) (in press

Dendrilla nigra, a marine sponge, as potential source of antibacterial substances for managing shrimp diseases

Secondary metabolites of marine sponge Dendrilla nigra were tested for determining the efficacy of controlling shrimp bacterial pathogens. Based on the exploratory experiments, the chosen dose of D. nigra (500 mg/kg of shrimp) was used for pilot experiment. The percent relative protection (PRP) of shrimps treated with Dendrilla feed and challenged with various concentrations of bacterial pathogen was evaluated. Dendrilla feed elicited complete protection (100% survival) against the most common shrimp pathogens such as luminescent Vibrio harveyi and Vibrio alginolyticus. Results of combined bacterial challenge indicated that Dendrilla was a broad spectrum vibriostatic agent. Invariably, the survival of treated shrimp against the bacterial infection was significant at p<0.01 level. Based on the present findings, it could be inferred that the secondary metabolites of D. nigra form an excellent source for developing potent antibacterial agents to combat bacterial diseases of shrimp and replace the conventional antibiotic

Impact of environment variables on pelagic fish landings: Special emphasis on Indian oil sardine off Tiruchendur coast, Gulf of Mannar

Results of the present study reported the correlation of various environmental variables such as dissolved oxygen (DO), chlorophyll ‘a’, primary productivity (PP), salinity, sea surface temperature (SST) and meteorological parameters such as air temperature (AT), air pressure (AP), relative humidity (RH), wind pattern, sunshine hours (SSH) and rainfall (RF) during January, 2008 to December, 2010 with that of the sardine fish landing along the Tiruchendur coast in Gulf of Mannar. The landings of the pelagic fishes like sardine, anchovy and Indian mackerel were high during south-west monsoon months extending from July to September in Tiruchendur coast. Sardines, which contribute 18.24% of the total fish catch, were recorded throughout the study period with a minimum occurrence during January and maximum in August. Large sized fishes were caught during October. It was found that, moderate temperature, high chlorophyll ‘a’ concentration and phytoplankton abundance are primary factors that enhance sardine fishery. Weather changes, influences fisheries through the modification of habitat characteristics, affecting the organisms to the extent that the physical, chemical and biological conditions that influence their productivity, development, nourishment and reproduction distribution are altered. Subtle changes in key environmental variables can drastically modify the abundance, distribution, and availability of fish populations

Methods for the rapid diagnosis and control of bacterial diseases in shellfishes and finfishes

The culture of finfish and shellfish are often threatened by disease causing bacteria. At times it is difficult to distinguish between infection with a pathogen and disease that may result from such infections. In addition, the stressed animals (physiological or environmental) are easily predisposed to encounter bacterial infections as well as diseases

Shrimp disease management using bioactive marine secondary metabolites: an ecofriendly approach

Vibriosis caused by opportunistic and secondary bacterial pathogens is still a serious disease problem in aquaculture of the black tiger shrimp Panaeus monodon. Attempts were made for controlling shrimp bacterial diseases using marine Secondary Metabolites (MSMs). Findings indicated that the MSMs of seaweed Ulva fasciata and sponge Dendrilla nigra are effective for controlling shrimp bacterial pathogen

Pathogenicity, antibiogram and biochemical characteristics of Luminescent Vibrio harveyi, associated with 'Black Shell Disease' of Penaeus monodon

Bacterial isolation was made from shrimps Penaeus monodon showing characteristic external symptoms of 'black shell disease' from shrimp farms located in southeast coast of India. The isolates were screened on TeBS agar plates and 0/129 for the selective isolation of Vibrio sp. Based on the morphological, biochemical and physiological characteristics, the isolate (RJM5) was characterized as luminescent Vibrio harveyi." Antibiogram of V. Imrueyi indicated that it was highly sensitive to chloramphenicol. ciprofloxacin, nalidixic acid and streptomycin. The pathogenicity studies confirmed that the isolate (V.harveyi) was moderately virulent

Immunomodulatory potential of marine secondary metabolites against bacterial diseases of shrimp

Shrimp disease management using bioactive marine secondary metabolites (MSMs) was developed as a package of practice for the sustainable shrimp farming. Therefore, the effect of MSMs on the host defense factors of shrimp was evaluated in the present study. Findings indicated that Ulva diet significantly increase the defense factors such as haemogram, agglutination index, phagocytic rate, bacterial clearance and serum bactericidal activity of treated shrimps over the control group. Based on the gut bacterial load, Ulva diet was considered as proactive drug whereas Dendrilla diet was determined as a curative agent

Optimization and characterization of a new lipopeptide biosurfactant produced by marine Brevibacterium aureum MSA 13 in solid state culture

The biosurfactant production of a marine actinobacterium Brevibacterium aureum MSA 13 was optimized using industrial and agroindustrial solid waste residues as substrates in solid state culture

The role of microtubule movement in bidirectional organelle transport

We study the role of microtubule movement in bidirectional organelle transport in Drosophila S2 cells and show that EGFP-tagged peroxisomes in cells serve as sensitive probes of motor induced, noisy cytoskeletal motions. Multiple peroxisomes move in unison over large time windows and show correlations with microtubule tip positions, indicating rapid microtubule fluctuations in the longitudinal direction. We report the first high-resolution measurement of longitudinal microtubule fluctuations performed by tracing such pairs of co-moving peroxisomes. The resulting picture shows that motor-dependent longitudinal microtubule oscillations contribute significantly to cargo movement along microtubules. Thus, contrary to the conventional view, organelle transport cannot be described solely in terms of cargo movement along stationary microtubule tracks, but instead includes a strong contribution from the movement of the tracks.Comment: 24 pages, 5 figure

Scaffolding School Pupils’ Scientific Argumentation with Evidence-Based Dialogue Maps

This chapter reports pilot work investigating the potential of Evidence-based Dialogue Mapping to scaffold young teenagers’ scientific argumentation. Our research objective is to better understand pupils’ usage of dialogue maps created in Compendium to write scientific ex-planations. The participants were 20 pupils, 12-13 years old, in a summer science course for “gifted and talented” children in the UK. Through qualitative analysis of three case studies, we investigate the value of dialogue mapping as a mediating tool in the scientific reasoning process during a set of learning activities. These activities were published in an online learning envi-ronment to foster collaborative learning. Pupils mapped their discussions in pairs, shared maps via the online forum and in plenary discussions, and wrote essays based on their dialogue maps. This study draws on these multiple data sources: pupils’ maps in Compendium, writings in science and reflective comments about the uses of mapping for writing. Our analysis highlights the diversity of ways, both successful and unsuccessful, in which dialogue mapping was used by these young teenagers