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.

Weight based adaptive clustering in wireless ad hoc networks

Abstract: This paper proposes a new weight based adaptive clustering algorithm (WBACA) for mobile ad-hoc networks (MANETs). MANETs are multi-hop wireless packet networks in which all the nodes cooperatively maintain network connectivity without the aid of any infrastructure networks. The proposed WBACA takes into account the transmission power, transmission rate, mobility, battery power and the degree of a node for forming clusters. Unlike the lowest-ID algorithm, which finds only the local minima of IDs and the weighted clustering algorithm (WCA), which finds the global minima of weights, the proposed WBACA finds the local minima of weights for the clustering process. Through simulations, we have compared the performance of our algorithm with that of the lowest-ID and WCA algorithms in terms of the number of clusters formed, number of reaffiliations, and the time delay in starting up the clustering process. The results demonstrate the superior performance of the proposed algorithm.

Assessment of the performance of CORDEX-South Asia experiments for monsoonal precipitation over the Himalayan region during present climate: part I

Abstract: Analysis of regional climate simulations to evaluate the ability of 11 Coordinated Regional Climate Downscaling Experiment in South Asia experiments (CORDEX-South Asia) along with their ensemble to produce precipitation from June to September (JJAS) over the Himalayan region have been carried out. These suite of 11 combinations come from 6 regional climate models (RCMs) driven with 10 initial and boundary conditions from different global climate models and are collectively referred here as 11 CORDEX South Asia experiments. All the RCMs use a similar domain and are having similar spatial resolution of 0.44° (~50 km). The set of experiments are considered to study precipitation sensitivity associated with the Indian summer monsoon (ISM) over the study region. This effort is made as ISM plays a vital role in summertime precipitation over the Himalayan region which acts as driver for the sustenance of habitat, population, crop, glacier, hydrology etc. In addition, so far the summer monsoon precipitation climatology over the Himalayan region has not been studied with the help of CORDEX data. Thus this study is initiated to evaluate the ability of the experiments and their ensemble in reproducing the characteristics of summer monsoon precipitation over Himalayan region, for the present climate (1970–2005). The precipitation climatology, annual precipitation cycles and interannual variabilities from each simulation have been assessed against the gridded observational dataset: Asian Precipitation-Highly Resolved Observational Data Integration Towards the Evaluation of Water Resources for the given time period. Further, after the selection of the better performing experiment the frequency distribution of precipitation was also studied. In this study, an approach has also been made to study the degree of agreement among individual experiments as a way to quantify the uncertainty among them. The experiments though show a wide variation among themselves and individually over time and space in simulating precipitation distribution over the study region, but noticeably along the foothills of the Himalayas all the simulations show dry precipitation bias against the corresponding observation. In addition, as we move towards higher elevation regions these experiments in general show wet bias. The experiment driven by EC-EARTH global climate model and downscaled using Rossby Center regional Atmospheric model version 4 developed by Swedish Meteorological and Hydrological Institute (SMHI-RCA4) simulate precipitation closely in correspondence with the observation. The ensemble outperforms the result of individual experiments. Correspondingly, different kinds of statistical analysis like spatial and temporal correlation, Taylor diagram, frequency distribution and scatter plot have been performed to compare the model output with observation and to explain the associated resemblance, robustness and dynamics statistically. Through the bias and ensemble spread analysis, an estimation of the uncertainty of the model fields and the degree of agreement among them has also been carried out in this study. Overview of the study suggests that these experiments facilitate precipitation evolution and structure over the Himalayan region with certain degree of uncertainty.

Meteorological conditions, seasonal and annual mass balances of Chhota Shigri Glacier, western Himalaya, India

Abstract: We present the updated glaciological mass balance (MB) of Chhota Shigri Glacier, the longest continuous annual MB record in the Hindu-Kush Karakoram Himalaya (HKH) region. Additionally, 4 years of seasonal MBs are presented and analyzed using the data acquired at an automatic weather station (AWS-M) installed in 2009 on a lateral moraine (4863ma.s.l.). The glaciological MB series since 2002 is first recalculated using an updated glacier hypsometry and then validated against geodetic MB derived from satellite stereo-imagery between 2005 (SPOT5) and 2014 (Pleiades). Chhota Shigri Glacier lost mass between 2002 and 2014 with a cumulative glaciological MB of –6.72mw.e. corresponding to a mean annual glacier-wide MB (Ba) of –0.56mw.e. a–1. Equilibrium-line altitude (ELA0) for the steady-state condition is calculated as ~4950ma.s.l., corresponding to an accumulation–area ratio (AAR0) of ~61%. Analysis of seasonal MBs between 2009 and 2013 with air temperature from AWS-M and precipitation from the nearest meteorological station at Bhuntar (1050ma.s.l.) suggests that the summer monsoon is the key season driving the interannual variability of Ba for this glacier. The intensity of summer snowfall events controls the Ba evolution via controlling summer glacier-wide MB (Bs).

PLncPRO for prediction of long non-coding RNAs (lncRNAs) in plants and its application for discovery of abiotic stress-responsive lncRNAs in rice and chickpea.

Abstract: Long non-coding RNAs (lncRNAs) make up a significant portion of non-coding RNAs and are involved in a variety of biological processes. Accurate identification/annotation of lncRNAs is the primary step for gaining deeper insights into their functions. In this study, we report a novel tool, PLncPRO, for prediction of lncRNAs in plants using transcriptome data. PLncPRO is based on machine learning and uses random forest algorithm to classify coding and long non-coding transcripts. PLncPRO has better prediction accuracy as compared to other existing tools and is particularly well-suited for plants. We developed consensus models for dicots and monocots to facilitate prediction of lncRNAs in non-model/orphan plants. The performance of PLncPRO was quite better with vertebrate transcriptome data as well. Using PLncPRO, we discovered 3714 and 3457 high-confidence lncRNAs in rice and chickpea, respectively, under drought or salinity stress conditions. We investigated different characteristics and differential expression under drought/salinity stress conditions, and validated lncRNAs via RT-qPCR. Overall, we developed a new tool for the prediction of lncRNAs in plants and showed its utility via identification of lncRNAs in rice and chickpea.

Function and regulation of the pentose phosphate pathway in brain.

Abstract: Although the quantitative contribution of the pentose phosphate pathway to glucose metabolism in adult brain is small, numerous experiments using specific inhibitors and developmental studies (Table VI) confirm the importance and the "functional" role of this pathway in brain (for details, see reviews by Baquer et al., 1975, 1977). In this article, an attempt has been made to bring together the important findings regarding the localization, operation, and functional significance of the pentose phosphate pathway in nervous tissue. The presence of these enzymes in synaptosomes and their linkage with peroxidative mechanisms, monoamine oxidase, and glutathione pathways suggest that they may be serving an important role in brain in vivo. There are a number of aspects that require further study for an understanding of the role of the pentose phosphate pathway in brain, including its role in inhibitory and excitatory synapses, in the control of synaptic plasticity, and the relationship between the electroencephalogram and the pentose phosphate pathway in various neural populations.