Electric field induced localization phenomena in a ladder network with superlattice configuration: Effect of backbone environment

Electric field induced localization properties of a tight-binding ladder network in presence of backbone sites are investigated. Based on Green's function formalism we numerically calculate two-terminal transport together with density of states for different arrangements of atomic sites in the ladder and its backbone. Our results lead to a possibility of getting multiple mobility edges which essentially plays a switching action between a completely opaque to fully or partly conducting region upon the variation of system Fermi energy, and thus, support in fabricating mesoscopic or DNA-based switching devices.Comment: 9 pages, 6 figure

Plant growth promoting rhizobacteria (PGPR) and their eco-friendly strategies for plant growth regulation: a review

As a natural engineer, Plant Growth Promoting Rhizobacteria (PGPR) play an important role in increasing plant growth, yield and enhancing plant tolerance to stressful conditions. These beneficial bacteria take up their position in the rhizosphere, around the plants’ root tissues. They may be in, or on their host tissues and help to provide nutrients to their host plants. For sustainable agriculture, PGPR transmit their extensive assistance in ecosystem management, soil structure maintenance, stress management and plant morphology and physiology modulation in an environmentally friendly manner. Plant- PGPR interactions also stimulate nutrient acquisition and accumulation, improve plant performance and enhance plants’ tolerance to abiotic and biotic stresses. Beside these, PGPR are good biofertilizers and safe for our environment. Nanotechnological advances with PGPR applications are important today to increase the impact of PGPR in agriculture. Undoubtedly, PGPR concept is intimately involved with agriculture, horticulture, forestry and they are too enough to establish a vibrant environment. In this review we have focused on the versatility of PGPR-their performance and aimed to address some future prospects of PGPR as an eco-friendly tool for plant growth regulation

Influence of formamide on the thermal stability of DNA

The utility of formamide in the denaturation and renaturation of DNA has been examined. The melting temperature of duplex DNA is lowered by 0.6°C per per cent formamide. The depression of melting temperature is independent of the GC content. Formamide also increases the width of the thermal transition. Upto 30%, it does not affect the rate of DNA reassociation

Predicting the Spatial Distribution of Rain-Induced Shallow Landslides by applying GIS and Geocomputational Techniques: A Case Study from North East India

This study presents a case of statistical modelling, by applying GIS and geocomputational techniques, to predict areas that are susceptible to future rain-induced shallow landslides. The statistical prediction model is based on the observed relationships between the spatial distribution of past landslideevents and environmental (causal) factors that are associated with such phenomena. The study also evaluates the predictive performance of a nonlinear regression model, namely the Generalized Additive Model(GAM),applied for the analysis. The study area comprises a residual hill of ? 6 Km2 area situated in the heart of Guwahati (capital city of Assam in NE India). We exploited the geoprocessing functions of SAGA GIS to derive nine different terrain attributesfrom a digital elevation model (DEM) processed by synthetic aperture radar interferometry (InSAR). The terrain attributes along with land use classes, in raster grid format, constitute the predictor variables. An inventory of the locations of eighty-two past occurrences of shallow landslide events constitutes the response. We performed the modelling and statistical geocomputation entirely in the open-source R language and software environment. The procedure comprises the following three steps: (1) Collinearityanalysis to discard redundant predictors. (2) 100-fold bootstrap resampling to fit the GAM by a random selection of 2/3 of the landslide pixels ("training" subset) and validate the GAM by the remaining 1/3 ("test" subset). (3) Estimate model accuracy (true error rates) by a repeated 100-fold 'hold-out validation' method and evaluate the predictive performance of the model by the Area under the ROC curve (AUROC) computed for 100 independently trained models. The mean and standard deviation of accuracy on training sets are 0.80 and 0.01, and that on test sets are 0.79 and 0.02 respectively. The AUROC corresponding to the meanof landslide probabilities is 0.87, and that of the 95% Confidence Intervals (CI) is between 0.86 and 0.88. Thevalues of these quality measures indicate that a data-driven model, such as the GAM, is efficient regarding its predictive performance, to highlight the unstable areas in the study area. We subsequently used the mean values of the landslide probability (susceptibility) estimates corresponding to each mapping unit (grid cell) to construct the landslide susceptibility map, which can be used for land use planning and hazard mitigation