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Gender plasticity uncovers multiple sexual morphs in natural populations of Cedrus deodara (Roxb.) G. Don

Ecological Processes 2021年第1期10卷 459-469页

作者： Vinod Prasad Khanduri Arun sukumaran chandra mohan s.arma Department of Forestry College of ForestryVCSG Uttarakhand University of Horticulture and ForestryRanichauriTehri GarhwalUttarakhand 249199India Present Address:state Farming Corporation of Kerala Chithalvetty EstateKalanjoor KollamKeralaIndia.

Background:The expression of gender in gymnosperms is challenging because the extent of variability in gender segregations in tree crowns and selection pressure of nature can modify the gender through ***:An in-depth investigation on spatial segregation of genders in tree crowns and sex expression of a total of 500 trees in five different natural populations of Cedrus deodara was carried out and verified the occurrence of subdioecious(co-existence of male,female,and monoecious)genders in ***:Five different sexual morphs were apparent among the 500 selected individuals as(1)pure male(M):bearing only male strobili in the whole crown with 22.2%;(2)pure female(F):bearing only female strobili in the whole crown with 12.4%;(3)mixed-monoecious(MM):bearing both male and female strobili with 13.6%;(4)predominantly female(PF)with 25.6%;and(5)predominantly male(PM)with 26.2%.The occurrence of multiple sexual morphs resulted from the complex selection pressure,which increased the stability of the *** segregation of genders in crown layers deemed to increase the fitness that may be a mechanism for accelerating *** results of the study suggest that the subdioecious gender expression in *** is evolved through the monoecy–paradioecy *** production of male strobili revealed non-significant effect of tree sizes whereas a significant effect was observed for the production of female *** study established that the total pollen and seed outputs in *** changed frequently according to gender ***:The size of the tree,resource availability,sex allocation,plant architecture,gender segregation in crowns,and habitat conditions are the prominent causes for gender plasticity.

关键词： Gender sex expression Gender segregation strobili Pre-fertilisation Monoecy Dioecy

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Impact of Land-Use Change on soil Microbial Community Composition and Organic Carbon Content in the Dry Tropics

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Pedosphere 2017年第5期27卷 974-977页

作者： chandra mohan KUMAR Nandita GHOsHAL Centre of Advanced study in Botany Department of Botany Institute of Science Banaras Hindu University

Restoration of forests poses a major challenge globally, particularly in the tropics, as the forests in these regions are more vulnerable to land-use change. We studied land-use change from natural forest(NF) to degraded forest(DF), and subsequently to either Jatropha curcas plantation(JP) or agroecosystem(AG), in the dry tropics of Uttar Pradesh, India, with respect to its impacts on soil microbial community composition as indicated by phospholipid fatty acid(PLFA) biomarkers and soil organic carbon(sOC) content. The trend of bacterial PLFAs across all land-use types was in the order: NF > JP > DF> AG. In NF, there was dominance of gram-negative bacterial(G^-) PLFAs over the corresponding gram-positive bacterial(G^+) PLFAs. The levels of G^- PLFAs in AG and JP differed significantly from those in DF, whereas those of G^+ PLFAs were relatively similar in these three land-use types. Fungal PLFAs,however, followed a different trend: NF > JP > DF = AG. Total PLFAs, fungal/bacterial(F/B) PLFA ratio, and sOC content followed trends similar to that of bacterial PLFAs. Across all land-use types, there were strong positive relationships between sOC content and G-, bacterial, fungal, and total microbial PLFAs and F/B PLFA ratio. Compared with bacterial PLFAs, fungal PLFAs appeared to be more responsive to land-use change. The F/B PLFA ratio, fungal PLFAs, and bacterial PLFAs explained 91%, 94%,and 73% of the variability in sOC content, respectively. The higher F/B PLFA ratio in JP favored more soil C storage, leading to faster ecosystem recovery compared to either AG or DF. The F/B PLFA ratio could be used as an early indicator of ecosystem recovery in response to disturbance, particularly in relation to land-use change.

关键词： ecosystem recovery fungal/bacterial ratio natural forest phospholipid fatty acid (PLFA) plantation

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Pollinator-mediated self-pollination and reproductive assurance in an isolated tree of Magnolia grandiflora L.

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Ecological Processes 2020年第1期9卷 517-525页

作者： Arun sukumaran Vinod Prasad Khanduri chandra mohan s.arma College of Forestry VCSG Uttarakhand University of Horticulture and ForestryRanichauriTehri GarhwalUttarakhand 249199India

Background:The ability to produce seeds when pollinators or potential mates are scarce is one of the principal advantages of self-pollination in flowering ***,the role of pollinators mediating self-pollination to ensure seed set when pollen or potential mates are limited has received less *** study examined the reproductive consequences and involvement of pollinators in assuring seed set in an isolated tree of Magnolia grandiflora,a predominantly outcrossing ***:We tested various aspects of reproduction such as flower density,floral rewards,stigma receptivity,pollinator abundance and behaviour,fruit set and seed set,in two successive reproductive years(2015-2016).Results:Flowers of *** possess a suite of traits facilitating pollinator-mediated self-pollination(PMs),although the chances of autonomous self-pollination are reduced due to herkogamy,spatial separation of anther and *** mean pollen production/flower was 5,152,289±285,094 with a pollen-to-ovule ratio of 39430±*** found a significant positive correlation between number of visits and seed production for bees(r=0.5099,p=0.0007)and beetles(r=0.7159,p=0.00001),indicating these are effective at *** was a significant negative correlation for thrips(r=-0.3206,p=0.044)and no correlation for flies or *** percent fruit set was 100%and the seed set per ovule ranged between 19 and 20%.Conclusions:PMs will guarantee reproductive assurance and mitigate the effect of reduced mates or pollen limitation which is expected to increase the fecundity and establishment of individual trees in geographically isolated locations.

关键词： Pollinator-mediated self-pollination Magnolia grandiflora Autonomous self-pollination Pollinator behaviour Reproductive assurance

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Reproductive biology of Cornus capitata Wall. ex Roxb.: a native species in East Asia

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Journal of Forestry Research 2019年第6期30卷 2039-2050页

作者： Vinod Prasad Khanduri Arun sukumaran chandra mohan s.arma College of Forestry VCSG Uttarakhand University of Horticulture and Forestry

The reproductive biology of Cornus capitata was studied in detail from June 2014 to October 2015 in Tehri Garhwal, Uttarakhand, western Himalaya, India and elucidated floral morphology, confirming autogamy, geitonogamy, and xenogamy. A new inflorescence ball formed each year with developing fruits that were initiated the previous year; thus reproduction is a continuous cycle. The total pollen production within a tree ranged between 4.0 × 10~7 and 9.3 × 10~7. Anthesis peaked between 08:00 and 10:00. There was significant effect of micro-environmental condition on anthesis(F = 243.8, p = 3.01). A significant positive relationship between the number of lateral shoots and total inflorescence showed that the inflorescence production in C. capitate depends largely on the number of lateral shoots. Time and concentration of various solutions significantly affected pollen germination(time: F = 5.39, p = 0.002; concentration: F = 1.40,p = 0.234). Anthophora bees and thrips were observed as the main pollinators. There was a significant difference in seed set between natural and obligate self-pollination(t = 11.84, p = 1.99). significant effect was also observed on fruit size(t = 8.88, p = 2.09) between open and shaded conditions. sEM micrographs of pollen grains showed that the shape of dehydrated pollen grains differed greatly due to variations in the rate of dehydration among pollen grains within the anther. seed germination was observed only in quality seed derived from open pollination, supporting xenogamy in C. capitata. Findings of the present study will be of immense value in formulating effective conservation measures for the species in wild habitats.

关键词： Floral development Pollen production Pollination Pollinators Reproductive success sEM analysis

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Productivity status of traditional agrisilviculture system on northern and southern aspects in mid-hill situation of Garhwal Himalaya,India

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Journal of Forestry Research 2009年第2期20卷 137-143页

作者： Arvind Bijalwan chandra mohan s.arma V. K. sah College of Forestry and Environment Allahabad Agricultural Institute- Deemed University Department of Botany H.N.B. Garhwal University Department of Forest Ecology College of Forestry and Hill Agriculture G. B. Pant University of Agriculture and Technology

The productivity of traditional agrisilviculture system(agricultural crops + trees) was investigated in the northern and southern aspects of mid-hill situation in Garhwal Himalaya, Uttarakhand, India during the 2004?2006.A total of 19 tree species were studied in both northern and southern aspects, out of which 17 tree species were selected in northern aspect and 12 tree species in southern aspect for phytosociological characteristic analysis of trees in agrisilvicultural *** most dominant tree species are Grewia optiva, Celtis australis and Melia azedarach and successively grown under traditional agrisilviculture *** results show that the annual productivity of all tree species was 3 775 kg·ha-1·a-1 in northern aspect(site-N) and 3 101 kg·ha-1·a-1 in southern aspect(site-s).*** had the highest productivity in both site-N and site-s among the tree species, followed by ***, Quercus leucotrichophora and *** dominant agricultural crops were Eleusine coracana in summer cereals, Phaseolus vulgaris in summer pulses-oilseeds and Triticum aestivum in the winter season in the *** average biological productivity of agricultural crops in northern aspect was about 16% higher than that in southern aspect under traditional agrisilviculture *** sole agricultural crop productivity(without trees) in northern aspect was also higher than that in southern *** obvious difference in annual productivity of trees and agriculture crops was observed between northern aspect and southern *** overall productivity in traditional agrisilviculture system(crop + tree) was 24%(in northern aspect) and 21%(in southern aspect) higher than that in sole cropping system.

关键词： traditional agrisilviculture system sole agricultural system productivity phytosociology sole crop importance value index

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Optimization of Threshold Ranges for Rapid Flood Inundation Mapping by Evaluating Backscatter Profiles of High Incidence Angle sAR Images

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International Journal of Disaster Risk science 2012年第2期3卷 113-122页

作者： Panchagnula Manjusree L.Prasanna Kumar chandra mohan Bhatt Goru srinivasa Rao Veerubhotla Bhanumurthy Disaster Management support Group Remote Sensing Applications AreaNational Remote Sensing CentreIndian Space Research Organization(ISRO)BalanagarHyderabad 500625India

Rapid satellite-based flood inundation mapping and delivery of flood inundation maps during a flood event can provide crucial information for planners and decision makers to prioritize relief and rescue operations. The present study is undertaken to optimize the threshold ranges for the classification of flood water in synthetic Aperture Radar(sAR) images(of 20° to 49° incidence angles) for quick flood inundation mapping and response during flood disasters. This is done through assessing the signature of flood water in Horizontal transmit and Horizontal received(HH), Horizontal transmit and Vertical received(HV), Vertical transmit and Horizontal received(VH), and Vertical transmit and Vertical received(VV) polarization radar data. The mean backscattering signature profiles of various water bodies were analyzed to discriminate flood water from other water bodies. The study shows that there is better demarcation of land-water surface in HH polarization. VV polarization has the potential to identify partially submerged features, which can be useful in flood damage assessments. The backscatter of flood water in HV and VH is the same and both HV and VH polarizations are adequate for the mapping of flood water. At near range to far range,-8 to-12 d B,-15 to-24 d B, and-6 to-15 d B can be used as optimum ranges for the classification of flood water in HH, HV, and VV polarizations. These optimum threshold ranges can be applied to the automation of flood mapping using sAR images in near-real time, where much time was often spent on finding the thresholds in order to produce flood inundation maps in a short time from the onset of flood disasters and deliver such maps to the concerned agencies.

关键词： flood polarization signature

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Electro-osmotic flow of a second-grade fluid in a porous microchannel subject to an AC electric field

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Journal of Hydrodynamics 2013年第2期25卷 309-316页

作者： MIsRA J. C. chandra s. Department of Mathematics Institute of Technical Education and Research Siksha O Anusandhan University Department of Physics Sabang S. K. Mahavidyalaya Vidyasagar University

studies on electro-osmotic flows of various types of fluids in microchannel are of great importance owing to their multifold applications in the transport of liquids, particularly when the ionized liquid flows with respect to a charged surface in the presence of an external electric field. In the case of viscoelastic fluids, the volumetric flow rate differs significantly from that of Newtonian fluids, even when the flow takes place under the same pressure gradient and the same electric field. With this end in view, this paper is devoted to a study concerning the flow pattern of an electro-osmotic flow in a porous microchannel, which is under the action of an alternating electric field. The influence of various rheological and electro-osmotic parameters, e.g., the Reynolds number, Debye-Huckel parameter, shape factor and fluid viscoelasticity on the kinematics of the fluid, has been investigated for a secondgrade viscoelastic fluid. The problem is first treated by using analytical methods, but the quantitative estimates are obtained numerically with the help of the software MATHEMATICA. The results presented here are applicable to the cases where the channel height is much greater than the thickness of the electrical double layer comprising the stern and diffuse layers. The study reveals that a larger value of the Debye-Huckel parameter creates sharper profile near the wall and also that the velocity of electro-osmotic flow increases as the permeability of the porous microchannel is enhanced. The study further shows that the electro-osmotic flow dominates at lower values of Reynolds number. The results presented here will be quite useful to validate the observations of experimental investigations on the characteristics of electro-osmotic flows and also the results of complex numerical models that are necessary to deal with more realistic situations, where electro-osmotic flows come into the picture, as in blood flow in the micro-circulatory system subject to an elect

关键词： electrical double layer Debye length second-grade fluid Ionic energy

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p53:updates on mechanisms,biology and therapy(Ⅰ)

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Journal of Molecular Cell Biology 2019年第4期11卷 185-186页

作者： chandra s.Verma Bioinformatics Institute Agency for ScienceTechnology and Research(A*STAR)Singapore 138671 Department of Biological sciences National University of SingaporeSingapore 117543 school of Biological sciences Nanyang Technological UniversitySingapore 637551

In July 2017,the 17th International p53 Workshop was held in *** an attendanee of over 300 scientists from all over the world,the meeting was an outstanding success and many new observations about the p53 pathway were discussed for the first *** enthusiasm to gather these in sights into a form that would be available to the whole community led us and the editors of Journal of Molecular Cell Biology to design a special issue of the journal composed of articles and commentaries from some of the key contributors to the meeting.

关键词： p53 mechanisms biology and therapy

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ROBUsT HIGH ORDER CONVERGENCE OF AN OVERLAPPING sCHWARZ METHOD FOR sINGULARLY PERTURBED sEMILINEAR REACTION-DIFFUsION PROBLEMs

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Journal of Computational Mathematics 2013年第5期31卷 509-521页

作者： s. chandra sekhara Ra~ sunil Kumar Department of Mathematics Indian Institute of Technology Delhi Hauz khas New Delhi-110016 India

In this article we propose an overlapping schwarz domain decomposition method for solving a singularly perturbed semilinear reaction-diffusion problem. The solution to this problem exhibits boundary layers of width O（√ε ln（1/√ε）） at both ends of the domain due to the presence of singular perturbation parameter ε. The method splits the domain into three overlapping subdomains, and uses the Numerov or Hermite scheme with a uniform mesh on two boundary layer subdomains and a hybrid scheme with a uniform mesh on the interior subdomain. The numerical approximations obtained from this method are proved to be almost fourth order uniformly convergent （in the maximum norm） with respect to the singular perturbation parameter. Furthermore, it is proved that, for small ε, one iteration is sufficient to achieve almost fourth order uniform convergence. Numerical experiments are given to illustrate the theoretical order of convergence established for the method.

关键词： singular perturbation semilinear reaction-diffusion Overlapping schwarzmethod Robust convergence Numerov scheme.

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Game theory-based attack and defense analysis in virtual wireless networks with jammers and eavesdroppers

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Digital Communications and Networks 2021年第3期7卷 327-334页

作者： Bassma s.Alsulami chandra Bajracharya Danda B.Rawat Department of Electrical Engineering and Computer science Howard UniversityWashingtonDC20059USA Department of Electrical Engineering Capitol Technology UniversityLaurelMD20708USA

Dynamic spectrum sharing and cognitive radio networks were proposed to enhance the Radio Frequency(RF)spectrum ***,there are several challenges to realize them in real systems,such as sensing uncertainty causing issues to licensed users,business models for licensed service *** virtualization is regarded as a technology that leverages service level agreements to sublease unused or underutilized RF spectrum that addresses aforementioned issues and helps to significantly enhance the utilization of the RF spectrum,offer improved coverage and capacity of networks,enhance network security and reduce energy *** wireless virtualization,wireless networks'physical substrate is shared and reconfigured dynamically between virtual wireless networks through Mobile Virtual Network Operations(MVNOs).Wireless virtualization with dynamic configurable features of Wireless Infrastructure Providers(WIPs),virtualized wireless networks are vulnerable to a multitude of attacks,including jamming attacks and eavesdropping *** paper investigates a means of defense through the employment of coalition game theory when jammers try to degrade the signal quality of legitimate users,and eavesdroppers aim to reduce secrecy ***,we consider a virtual wireless network where MVNO users'job is to improve their signal to Interference plus Noise Ratio(sINR)while the jammers target to collectively enhance their Jammer Received signal strength(JRss),and an eavesdropper's goal is to reduce the overall secrecy *** results have demonstrated that the proposed game strategies are effective(in terms of data rate,secrecy rate and latency)against such attackers compared to the traditional approaches.

关键词： Game theory based security Virtual wireless networks Jamming and eavesdropping

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