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Syncytes during male meiosis resulting in 2n pollen grain formationin Lindelofia longiflora ***

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Journal of Systematics and Evolution 2011年第5期49卷 406-410页

作者： Vijay kumar SINGHAL pawan kumar RANA Puneet kumar Department of Botany Punjabi University

Lindelofia longiflora(Royle ex Benth.) ***(Cl.) Brand(Family:Boraginaceae) is investigated cytologically(n = 12) for the first time from the cold deserts of Pangi Valley,Chamba District(Himachal Pradesh) in *** report the formation of syncytes and 2n pollen grains in the *** meiosis,the majority of the pollen mother cells(PMCs) exhibited 12 bivalents,equal segregation of chromosomes during anaphases,regular tetrads,and normal-sized pollen grain ***,two proximate PMCs fused during the early stages of prophase-I and resulted in the formation of *** frequency of syncytes in the accession is rather low,at 25 out of 1866(1.33%).Such syncyte PMCs are detectable during meiosis due to their larger size compared to typical *** syncytes or polyploid cells showed normal 24 bivalents and depicted perfectly regular meiotic *** the products of such PMCs yield 2n or larger sized pollen grains that are almost double the size of typical normal or n pollen *** origin of syncytes as a consequence of the fusion of meiocytes during the early stages of meiosis-I could be attributed to low temperature stress conditions prevailing in the Pangi Valley,where temperature during May and June dip to below freezing,the time the plants enters the reproductive/flowering bud *** is possible that such apparently fertile 2n pollen grains originating from syncytes might play a role in the origin of intraspecific polyploids in the species.

关键词： bivalents cold deserts low temperature stress Pangi Valley PMCs pollen grains.

A neighborhood proximity based algorithm for overlapping community structure detection in weighted networks

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Frontiers of Computer Science 2019年第6期13卷 1353-1355页

作者： pawan kumar Ravins DOHARE Centre for Interdisciplinary Research in Basic Sciences Jamia Millia IslamiaNew Delhi-110025India

1 Introduction Many real networks are inherently composed of overlapping structure at modular level where nodes have multiple ***,many real networks are equipped with several metadata such as ground truth,node and edge weights which make the whole business of community detection ***,there are a few well known algorithms,e.g.,CPMw[1]that can detect overlapping community structure in weighted *** it comes to the application of an algorithm,the desired output depends on the right choice of parameters.

关键词： networks structure algorithm

Coordination polymers： Challenges and future scenarios for capture and degradation of volatile organic compounds

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Nano Research 2016年第11期9卷 3181-3208页

作者： Kowsalya Vellingiri pawan kumar Ki-Hyun Kim Department of Civil and Environmental Engineering Hanyang uniVersity 222 Wangsimni-RoSeoul 04763Republic of Rorea Department of Nano Sciences and Materials Central University of Jammu Jammu 181143 India

Over the past few decades, coordination polymers/metal organic frameworks （CPs/MOFs） have drawn a great deal of attention for diverse applications due to their advantages of intrinsically ttLnable chemical structure, flexible architecture, high pore volume, high surface area, multifunctional properties, etc. To date, numerous CPs/MOFs have been developed and employed for the treatment and control of gaseous pollutants, such as volatile organic compounds （VOCs）, through capture, sorptive removal, and catalytic degradation. Nevertheless, there are also some key drawbacks and challenges for the practical application of these systems （e.g., poor selectivity, high energy （and fiscal） cost, high synthesis cost, low capacity, and difficulties in regeneration and recycling）. In this review, recent developments in CPs/MOFs research are described with their associated mechanisms for capture, sorptive removal, and catalytic degradation of VOCs. To this end, we discuss the key variables and challenges for afforded abatement of VOCs through CPs/MOFs technologies. Hopefully, this review will help the scientific community set future directions for the advancement of CPs/MOFs techniques for the effective management of diverse environmental issues.

关键词： coordination polymers/metal organic frameworks(CPs/MOFs) volatile organic compounds sorptive removalcatalytic degradation

Recent development in upconversion nanoparticles and their application in optogenetics:A review

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Journal of Rare Earths 2022年第6期40卷 847-861,I0001页

作者： Madhumita Patel Maninder Meenu Jitender kumar Pandey pawan kumar Rajkumar Patel Department of Chemistry and Nano Science Ewha Womans UniversitySeodaemun-guSeoul120-750South Korea College of Biosystems Engineering and Food Science Zhejiang UniversityHangzhou 310058China School of Basic and Applied Sciences Adamas UniversityKolkata700126India Institut National de la Recherche Scientifique-Centreénergie Materiaux Télecommunications(INRS-EMT) VarennesQCCanada Department of Chemistry and Biochemistry University of Oklahoma101 Stephenson ParkwayNormanOK73019United States Energy&Environmental Science and Engineering(EESE) Integrated Science and Engineering Division(ISED)Underwood International CollegeYonsei University85 Songdogwahak-roYeonsu-guIncheon21983South Korea

Ion channels present in the plasma membrane are responsible for integration and propagation of electric signals,which transmit information in nerve *** of these ion channels leads to many neurological ***,optogenetic technology has gained a lot of attention for the manipulation of neuronal *** is a neuromodulation approach that has been developed to control neuronal functions and activities using *** lanthanide-doped upconversion nanoparticles(UCNPs)absorb low energy photons in near-infrared(NIR) window and emit high energy photons in the visible spectrum region via nonlinear *** the last few decades,UCNPs have gained great attention in various bio-medical applications such as bio-imaging,drug delivery and *** near-infrared illumination is considered more suitable for optogenetics application,due to its lower degree of light attenuation and higher tissue penetration compared to visible ***,UCNPs have been considered as the new promising candidates for optogenetics *** nanoparticlemediated optogenetic systems provide a great opportunity to manipulate the ion channel in deep ***,we summarize the upconversion photoluminescence in lanthanide doped nanomaterials and its mechanisms and several approaches adopted to tune emission color or enhance upconversion *** advances of lanthanide-doped UCNPs design strategy and their mechanism are ***,we discuss the neural circuitry modulation using upconversion nanoparticles mediated ***,the future perspectives towards optogenetics are also included.

关键词： Lanthanide Upconversion Optogenetics Nanoparticles Neuronal modulation Rare earths

An indicator-based approach to assess village-level social and biophysical vulnerability of agriculture communities in Uttarakhand,India

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Journal of Mountain Science 2016年第12期13卷 2260-2271页

作者： Roopam SHUKLA Kamna SACHDEVA pawan kumar JOSHI Department of Natural Resources TERI University School of Environmental Sciences Jawaharlal Nehru University

With the growing recognition to myriad forms of current and future threats in the mountain agriculture systems,there is a pressing need to holistically understand the vulnerability of mountain agriculture *** study aims to assess the biophysical and social vulnerability of agriculture communities using an indicator-based approach for the state of Uttarakhand,India.A total of 14 indicators were used to capture biophysical vulnerability and 22 for social vulnerability profiles of15285 *** analysis was done at village level with weights assigned to each indicator using Analytical Hierarchical Process(AHP).The results of the study highlight the presence of very high biophysical vulnerability(0.82 ± 0.10) and high social vulnerability(0.65 ± 0.15) within the *** on the results,it was found that incidences of high biophysical vulnerability coincide with presence of intensified agriculture land and absence of dense *** social vulnerability scores were found in villages with an absence of local institutions(like Self Helping Groups(SHGs)),negligible infrastructure facilities and higher occupational dependence on agriculture.A contrast was observed in the vulnerability scores of villages present in the three different altitudinal zones in the study area,indicating respective vulnerability generating conditions existing in these three *** vulnerability was recorded to be highest in the villages falling in the lower zone and lowest in the upper zone villages;whereas,social vulnerability was found to be highest in the middle zone villages and lowest in lower zone *** study aids policy makers in identifying areas for intervention to expedite agriculture adaptation planning in the ***,the adaptation programmes in the region need to be more context-specific to accommodate the differential altitudinal vulnerability profiles.

关键词： Social vulnerability Biophysical vulnerability Mountain agriculture communities AHP Uttarakhand

Implications of Climate Change on Streamflow of a Snow-Fed River System of the Northwest Himalaya

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Journal of Mountain Science 2013年第4期10卷 574-587页

作者： Vaibhav SHARMA Varunendra Dutta MISHRA pawan kumar JOSHI Snow and Avalanche Study Establishment Chandigarh 160036 India TERI University Institutional AreaDelhi 110070 India

Air temperature and snow cover variability are sensitive indicators of climate change. This study was undertaken to forecast and quantify the potential streamflow response to climate change in the Jhelum River basin. The implications of air temperature trends （＋0.11℃decade） reported for the entire north-west Himalaya for past century and the regional warming （＋0.7℃/decade） trends of three observatories analyzed between last two decades were used for future projection of snow cover depletion and stream flow. The streamflow was simulated and validated for the year 2007-2008 using snowmelt runoff model （SRM） based on in-situ temperature and precipitation with remotely sensed snow cover area. The simulation was repeated using higher values of temperature and modified snow cover depletion curves according to the assumed future climate. Early snow cover depletion was observed in the basin in response to warmer climate. The results show that with the increase in air temperature, streamfiow pattern of Jhelum will be severely affected. Significant redistribution of streamflow was observed in both the scenarios. Higher discharge was observed during spring-summer months due to early snowmelt contribution with water deficit during monsoon months. Discharge increased by 5%-40% during the months of March to May in 2030 and 2050. The magnitude of impact of air temperature is higher in the scenario-2 based on regional warming. The inferences pertaining to change in future streamflow pattern can facilitate long term decisions and planning concerning hydro-power potential, waterresource management and flood hazard mapping in the region.

关键词： Snowmelt Snow cover depletion curve(SCDC) Climate change Global warming Streamflow SRM Jhelum

Tracking sources and paleotectonic settings of Mesozoic sandstones in interlinked rift basins of western India:An integrated approach using petrography and heavy mineral chemistry

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Journal of Palaeogeography 2022年第2期11卷 173-193页

作者： pawan kumar Rajak Angana Chaudhuri Naraga Prabhakar Santanu Banerjee Department of Earth Sciences Indian Institute of Technology BombayMumbai 400076India

Based on integration of field,petrographic and heavy mineral chemical data,this study highlights the source and tectonic setting of the Mesozoic sandstones of Kutch,Saurashtra,Narmada and Cambay basins at the western margin of India,formed by the progressive splitting of the eastern *** Kutch Basin is dominated by arkosic sandstone,whereas Saurashtra,Narmada and Cambay basins show the predominance of sub-arkose and *** modal analyses of framework grains in Kutch sandstones indicate basement uplift and transitional continent *** contrast,the sandstones of Saurashtra,Narmada and Cambay basins bear imprints of recycled orogenic and craton interior *** presence of abraded and detrital quartz overgrowth and rounded zircons in most sandstones reveal the recycling of sediments in these *** and rutile mineral compositions constrain the possible lithology of source *** tourmaline mineral chemistry(Ca-Fe_(tot)-Mg plot)suggests the derivation of sediments from various sources,including Li-poor granitoids associated with pegmatites,aplites,Ca-poor metapelites,metapsammites and quartz-tourmaline-rich granitic *** compositions of rutile grains(Cr *** plot)in sandstones indicate metapelitic *** gamut of all mineral chemical data supports the predominance of sediment sources from quartzo-feldspathic rocks with minor inputs from mafic *** on available paleocurrent data and correlation of source compositions,we infer that the Mesozoic sediments of Kutch,Saurashtra,Narmada and Cambay basins were primarily sourced by various lithologies of the Aravalli *** Narmada Basin possibly received additional sediment input from the Bundelkhand Craton.

关键词： Mesozoic sandstones Rift basins Tourmaline chemistry Rutile chemistry Kutch Basin Saurashtra Basin Cambay Basin Narmada Basin

Hybridization between salt resistant and salt susceptible genotypes of mungbean(Vigna radiata ***)and purity testing of the hybrids using SSRs markers

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Journal of Integrative Agriculture 2016年第3期15卷 521-527页

作者： Sehrawat Nirmala Yadav Mukesh Bhat Kangila Venkataraman Sairam Raj kumar Jaiwal pawan kumar Centre for Biotechnology Maharshi Dayanand UniversityRohtak 124001India Department of Biotechnology Maharishi Markandeshwar UniversityAmbala 133207India National Bureau of Plant Genetic Resources Pusa CampusNew Delhi 110012India Indian Society for Plant Physiology G-3NASC ComplexPusaNew Delhi 110012India

Six cultivated and two wild genotypes of mungbean（Vigna radiata L. Wilczek） possessing variation for phenotypic and genotypic response for salt tolerance were hybridized. Hybridization results showed successful pod set and significant variations in cross-compatibility of investigated genotypes. Genotypes PLM 380 and PLM 562 showed promising combining ability with all genotypes. Results revealed significant crossing compatibility between V. radiata and V. sublobata. The cross ability ranged from 1.99 to 5.12%（average 3.08%）. Molecular analysis confirmed the hybrids purity. All F_1 seeds were bold, green/shiny green and germinated between 3 to 5 days. Hybrid plants were normal, fertile and healthier over their respective progenitors. Uniform flowering and maturity of the hybrids showed absence of any defect or alteration in plant habit and life cycle of the hybrids. The hybrid plants showed increase in yield characteristics as no. of pods, pod length, 100 seeds weight, and yield per plant. Number of pods containing F_2 seeds ranged from 5–8 per cluster. The F_2 seeds were collected and stored for further research. Present study suggests that salt resistant wild relatives or cultivars of mungbean can be explored by breeding as a source of useful traits/genes providing salt tolerance. This may help in development of best mungbean variety for saline prone areas. Micro-satellite markers linked to the trait/genes may assist breeding by early selection of the genotypes compared to the phenotypic screening.

关键词： mungbean salinity stress breeding hybrid purity improved characteristics

Multi-temporal forest cover dynamics in Kashmir Himalayan region for assessing deforestation and forest degradation in the context of REDD+ policy

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Journal of Mountain Science 2016年第8期13卷 1431-1441页

作者： Akhlaq Amin WANI pawan kumar JOSHI Ombir SINGH Sumera SHAFI Faculty of Forestry Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir School of Environmental Sciences Jawaharlal Nehru University Silviculture Division Forest Research Institute (FRI) KVK Pulwama Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir

The role of forests is being actively considered under the agenda of REDD＋（Reducing Emissions from Deforestation and Forest Degradation plus） aimed at reducing emissions related to changes in forest cover and forest quality. Forests in general have undergone negative changes in the past in the form of deforestation and degradation, while in some countries positive changes are reported in the form of conservation, sustainable management of forests and enhancement of carbon stock. The present study in the Kashmir Himalayan forests is an effort to assess historical forest cover changes that took place from 1980 to 2009 and to predict the same for 2030 on the basis of past trend using geospatial modeling approach. Landsat data （Multispectral Scanner （MSS）, Thematic Mapper （TM） and Enhanced Thematic Mapper （ETM＋）） was used for the years 1980, 199o and （2001, 2009） respectively and change detection analysis between the dates was performed. The maps generated were validated through ground truthing. The study area （3375.62 km^2） from 1980-2009 has uffered deforestation and forest degradation of about 126 km^2 and 239.02 km^2 respectively which can be claimed under negative options of REDD＋, while as the area that experienced no change （1514 km^2） can be claimed under conservation. A small area （23.31 km^2） observed as positive change can be claimed under positive options. The projected estimates of forest cover for 2030 showed increased deforestation and forest degradation on the basis of trend analysis using Cellular Automata （CA） Markov modeling. Despite the fact that country as a whole has registered a net positive change in the past few decades, but there are regions like Kashmir region of western Himalaya which have constantly undergoing deforestation as well as degradation in the past few decades.

关键词： Deforestation Degradation Coniferous forests Carbon emission Himalaya