Jawaharlal Nehru University

About: Jawaharlal Nehru University is a education organization based out in New Delhi, India. It is known for research contribution in the topics: Population & Politics. The organization has 6082 authors who have published 13455 publications receiving 245407 citations. The organization is also known as: JNU.

Amplitude Death: The emergence of stationarity in coupled nonlinear systems

Abstract: When nonlinear dynamical systems are coupled, depending on the intrinsic dynamics and the manner in which the coupling is organized, a host of novel phenomena can arise. In this context, an important emergent phenomenon is the complete suppression of oscillations, formally termed amplitude death (AD). Oscillations of the entire system cease as a consequence of the interaction, leading to stationary behavior. The fixed points that the coupling stabilizes can be the otherwise unstable fixed points of the uncoupled system or can correspond to novel stationary points. Such behaviour is of relevance in areas ranging from laser physics to the dynamics of biological systems. In this review we discuss the characteristics of the different coupling strategies and scenarios that lead to AD in a variety of different situations, and draw attention to several open issues and challenging problems for further study.

A portfolio approach to analyzing complex human-environment interactions:Institutions and land change

Abstract: The challenge confronting those seeking to understand the institutional dimensions of global environmental change and patterns of land-use and land-cover change is to find effective methods for analyzing the dynamics of socio-ecological systems. Such systems exhibit a number of characteristics that pose problems for the most commonly used statistical techniques and may require additional and innovative analytic tools. This article explores options available to researchers working in this field and recommends a strategy for achieving scientific progress. Statistical procedures developed in other fields of study are often helpful in addressing challenges arising in research into global change. Accordingly, we start with an assessment of some of the enhanced statistical techniques that are available for the study of socio-ecological systems. By themselves, however, even the most advanced statistical models cannot solve all the problems that arise in efforts to explain institutional effectiveness and patterns of land-use and land-cover change. We therefore proceed to an exploration of additional analytic techniques, including configurational comparisons and meta-analyses; case studies, counterfactuals, and narratives; and systems analysis and simulations. Our goal is to create a portfolio of complementary methods or, in other words, a tool kit for understanding complex human-environment interactions. When the results obtained through the use of two or more techniques converge, confidence in the robustness of key findings rises. Contradictory results, on the other hand, signal a need for additional analysis.

Antioxidant enzyme activities in maize plants colonized with Piriformospora indica.

Abstract: The bioprotection performance of Piriformospora indica against the root parasite Fusarium verticillioides was studied. We found that maize plants first grown with F. verticillioides and at day 10 inoculated with P. indica showed improvements in biomass, and root length and number as compared with plants grown with F. verticillioides alone. To validate our finding that inoculation with P. indica suppresses colonization by F. verticillioides, we performed PCR analyses using P. indica- and F. verticillioides-specific primers. Our results showed that inoculation with P. indica suppresses further colonization by F. verticillioides. We hypothesized that as the colonization by P. indica increases, the presence of/colonization by F. verticillioides decreases. In roots, catalase (CAT), glutathione reductase (GR), glutathione S-transferase (GST) and superoxide dismutase (SOD) activities were found to be higher in F. verticillioides-colonized plants than in non-colonized plants. Increased activity of antioxidant enzymes minimizes the chances of oxidative burst (excessive production of reactive oxygen species), and therefore F. verticillioides might be protected from the oxidative defence system during colonization. We also observed decreased antioxidant enzyme activities in plants first inoculated with F. verticillioides and at day 10 inoculated with P. indica as compared with plants inoculated with F. verticillioides alone. These decreased antioxidant enzyme activities due to the presence of P. indica help the plant to overcome the disease load of F. verticillioides. We propose that P. indica can be used as a bioprotection agent against the root parasite F. verticillioides.