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两种草蛉对取食棉花的扶桑绵粉蚧的嗅觉反应(英文) 被引量:3
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作者 Sudhida GAUTAM ashok kumar singh Ram Dass GAUTAM 《昆虫学报》 CAS CSCD 北大核心 2010年第5期497-507,共11页
捕食性的普通草蛉Chrysoperla sp.(carnea group)和安平草蛉Mallada desjardinsi(Navas)(脉翅目:草蛉科)的寄主-生境定位取决于其觅食行为以及对各阶段释放的植物气味的行为反应。本研究调查了这两种交配的草蛉成虫以及取食棉花的扶桑... 捕食性的普通草蛉Chrysoperla sp.(carnea group)和安平草蛉Mallada desjardinsi(Navas)(脉翅目:草蛉科)的寄主-生境定位取决于其觅食行为以及对各阶段释放的植物气味的行为反应。本研究调查了这两种交配的草蛉成虫以及取食棉花的扶桑绵粉蚧Phenacoccus solenopsis的反应,以便了解它们之间的三重营养关系。结果表明:草蛉雄虫和雌虫均能感受到棉花植株释放的绿叶挥发物;植株的各个阶段均可使捕食性昆虫和绵粉蚧定位。在受绵粉蚧为害的棉叶上饱和烃含量高,说明草蛉成虫的反应更为强烈;在植株受为害期和开花期释放捕食性昆虫,可提高田间捕食性昆虫的作用。这些结果提示有效的生物防治取决于捕食性昆虫在植株上的天然定殖能力以及对害虫的吞食能力。 展开更多
关键词 普通草蛉 安平草蛉 扶桑绵粉蚧 三重营养关系 棉花 绿叶挥发物
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Repercussions of solar high energy protons on ozone layer during super storms 被引量:1
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作者 Asheesh Bhargawa Mohd Yakub ashok kumar singh 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2019年第1期21-28,共8页
We are very aware of the importance of the ozone layer, without which life on the Earth would not have evolved in the way it has. Solar storms carry energetic protons into the Earth's upper atmosphere,where they b... We are very aware of the importance of the ozone layer, without which life on the Earth would not have evolved in the way it has. Solar storms carry energetic protons into the Earth's upper atmosphere,where they boost production of nitrogen oxides which are known as ozone killers and which ultimately increase ultraviolet(UV) radiations. In the present study, we estimate the effects of solar energetic protons during super storms(Dst index <-300 nT) over the total ozone column for the last 32 yr. We select a total of seven super storm events that occurred during solar cycles 22–24(for the last 32 yr) having Dst index <-300 nT. To that end, we apply superposed epoch analysis(SEA) to verify the impact of storm events on the quantitative variation of total ozone column and on UV radiations during super storm events.After completing the empirical analysis, we conclude that the ozone column gets depleted significantly(22±6.8%) as proton density increases during super storm events and this decrement in the ozone level is further responsible for a substantial increase(26±11.2%) in peak UV radiation intensities. 展开更多
关键词 Sun:particle emission Sun:solar TERRESTRIAL RELATIONS Sun:astroparticle PHYSICS Sun:Physical Data and Processes
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Preliminary slope stability analysis and discontinuities driven susceptibility zonation along a crucial highway corridor in higher Himalaya, India 被引量:1
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作者 Barsa ACHARYA Kripamoy SARKAR +1 位作者 ashok kumar singh Sowmiya CHAWLA 《Journal of Mountain Science》 SCIE CSCD 2020年第4期801-823,共23页
Identification of failure susceptible slopes through different rock engineering approach is highly valuable in landslide risk management along crucial highway corridors in the high mountainous region. In this study, a... Identification of failure susceptible slopes through different rock engineering approach is highly valuable in landslide risk management along crucial highway corridors in the high mountainous region. In this study, a critical highway(NH-5) segment in higher Himalaya has been investigated using the various rock mass characterization schemes based on detailed field observations. Since the highway corridor is highly susceptible to discontinuities-driven failures, consisting of jointed rock masses;Mean and Combined kinematic feasibility analysis has been performed for 20 highway slopes. Observed slope mass classes have been compared to the feasibility percentage of discontinuities driven failures(wedge, toppling, and planar) and accordingly the kinematic feasibility zonation along highway segment has been done for each as well as overall failure types. Based on the slope mass conditions and discontinuities driven failures probability(%), responsive remedial measures have been proposed for individual highway slopes to ensure safe and uninterrupted transportation. 展开更多
关键词 SLOPE characterization Kinematic analysis Failure ZONATION map HIMALAYAN HIGHWAYS Landslide SLOPE stability
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Differential RNA Editing of Mitochondrial Genes in WA-Cytoplasmic Based Male Sterile Line Pusa 6A, and Its Maintainer and Restorer Lines
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作者 Umakanta NGANGKHAM Swarup kumar PARIDA +1 位作者 ashok kumar singh Trilochan MOHAPATRA 《Rice science》 SCIE CSCD 2019年第5期282-289,共8页
RNA editing changes the nucleotides at the transcript level of mitochondrial genes which results in synthesis of functional proteins.This study was designed to find the editing sites which could be implicated in male ... RNA editing changes the nucleotides at the transcript level of mitochondrial genes which results in synthesis of functional proteins.This study was designed to find the editing sites which could be implicated in male fertility restoration and to develop editing based markers for differentiation of cytoplasmic male sterility and maintainer lines from each other.DNA and RNA from young panicles were isolated from three-line system of hybrid rice PRH10,wild abortive(WA)cytoplasm based male sterile(A line Pusa 6A),maintainer(B line Pusa 6B)and restorer(R line PRR78)lines.Pusa 6A and PRR78 having the same WA cytoplasm are allo-nuclear and iso-cytpolasmic lines.The genomic and cDNA amplicons for eight mitochondrial genes(18SrRNA,atp6,atp9,cobII,coxI,coxIII,nadI and rps3)were sequenced and compared.Differences in genomic and cDNA sequences were considered as editing.Two hundred and thirty editing sites having base substitution or insertion/deletion were identified with the highest in 18SrRNA(5.74%)and the lowest in coxI(0.60%).The highest editing sites were observed in fertile maintainer Pusa 6B followed by PRR78 and Pusa 6A,of which random five editing sites in five different rice mitochondrial transcripts namely atp9,cobII,coxIII,rps3 and 18SrRNA were chosen and validated through cleaved amplified polymorphism sequence(CAPS)analysis and found to be partially edited in four genes.The identical editing sites of different mitochondrial genes from maintainer and restorer lines might reflect their possible contribution to fertility restoration of sterile WA cytoplasm. 展开更多
关键词 cleaved amplified polymorphism sequence CYTOPLASMIC male STERILITY hybrid rice RNAediting mitochondrial gene WILD abortive NUCLEOTIDE
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Effect of Heat Source/Sink on Free Convective Flow of a Polar Fluid between Vertical Concentric Annuli
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作者 Arun kumar singh ashok kumar singh 《Journal of Applied Mathematics and Physics》 2017年第9期1750-1762,共13页
The purpose of this paper is to find the effect of heat source/sink parameter on free convective flow of a polar fluid in open-ended vertical concentric annuli. Exact solutions of the non-dimensional differential equa... The purpose of this paper is to find the effect of heat source/sink parameter on free convective flow of a polar fluid in open-ended vertical concentric annuli. Exact solutions of the non-dimensional differential equations describing the flow model have been obtained one by one for two different cases of source and sink. To observe the effect of the physical parameters such as source/sink and vertex viscosity, the numerical results of the velocity and microrotational velocity are finally shown on the graphs. 展开更多
关键词 POLAR FLUID Free Convection Isothermal and Constant HEAT Flux Cases Temperature Dependent HEAT Source/Sink VERTICAL Annuli
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Microstructure, Texture, Mechanical and Ballistic Properties Correlation of a Hot Rolled and Peak Aged AA-7017 Alloy Plate at Surface and Centre
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作者 Pradipta kumar Jena Kandikattu Siva kumar +1 位作者 Rajiv kumar Mandal ashok kumar singh 《Materials Sciences and Applications》 2017年第13期992-1013,共22页
The present work describes microstructure, texture, mechanical and ballistic properties correlation of a hot rolled and peak aged AA-7017 alloy plate at surface and centre. Both the microstructures and textures are di... The present work describes microstructure, texture, mechanical and ballistic properties correlation of a hot rolled and peak aged AA-7017 alloy plate at surface and centre. Both the microstructures and textures are different on the surface and centre of the plate. The surface of the plate shows recrystallized grains and a weak over all texture. The centre of the plate displays elongated grains and a sharp texture. Tensile properties, hardness and impact toughness are evaluated at surface and centre of the plate. It is observed that strength and hardness is high at centre, whereas ductility and impact toughness is more at the surface. Ballistic properties of the plate at centre and surface are measured by impacting against two different 7.62 mm deformable projectiles. The plates impacted on the surface shows better ballistic resistance. Ballistic performance of the plate at surface and centre has been correlated with the microstructure, texture and mechanical properties. 展开更多
关键词 BALLISTIC Performance AA 7017 ALLOY MICROSTRUCTURE TEXTURE Mechanical PROPERTY BALLISTIC PROPERTY Anisotropy
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Analysis of Entropy Generation in a Rectangular Porous Duct
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作者 Shyam Lal Yadav ashok kumar singh 《Journal of Applied Mathematics and Physics》 2016年第7期1336-1343,共9页
In this paper, we have considered a fully developed flow of a viscous incompressible fluid in a rectangular porous duct saturated with the same fluid. The duct is heated from the bottom for forced and mixed convection... In this paper, we have considered a fully developed flow of a viscous incompressible fluid in a rectangular porous duct saturated with the same fluid. The duct is heated from the bottom for forced and mixed convection. The Brinkman model is used to simulate the momentum transfer in the porous duct. Using the momentum and thermal energy equations, the entropy generation has been obtained due to the heat transfer, viscous and Darcy dissipations. It is found from the mathematical analysis that the entropy generation is double when the viscous as well as the Darcy dissipations terms are taken in the thermal energy equation in comparison when the viscous as well as the Darcy dissipations terms are not taken in the thermal energy equation. This result clearly shows that there is no need of taking the viscous and Darcy dissipations terms in the thermal energy equation to obtain the entropy generation. 展开更多
关键词 Brinkman Model Heat Flux Fully Developed Flow Viscosity Ratio Entropy Generation
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Influence of temperature dependent heat source/sink on transient MHD free convective flow in an infinite rigid impermeable vertical cylinder with chemical reaction
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作者 Naveen Dwivedi ashok kumar singh Nirmal C.Sacheti 《Propulsion and Power Research》 SCIE 2023年第4期568-583,共16页
It is increasingly apparent that the inclusion of mass transfer aspects,together with certain thermal conditions,in the momentum and energy equations governing MHD flows leads to a numbers of real life applications.Ke... It is increasingly apparent that the inclusion of mass transfer aspects,together with certain thermal conditions,in the momentum and energy equations governing MHD flows leads to a numbers of real life applications.Keeping this in view,we have attempted an exact analysis of heat and mass transfer aspects in transient hydromagnetic free convective flow of an incompressible viscous fluid through a vertical pipe under an externally applied magnetic field,assuming presence of chemical reaction and heat source/sink.The governing PDEs,which simplify to a set of 3 linear ODEs in the physical set up considered here,have been solved using Laplace transform technique,with solutions for key physical variables presented in the term of Bessel and modified Bessel functions.The influence of governing non-dimensional parameters,namely,Hartmann number,Schmidt number,source/sink parameter,Prandtl number and chemical reaction parameter,has been illustrated on the developing velocity and some concentration profiles.Some important quantities of engineering interest-surface skin friction and volumetric flow rates-have been computed too and analysed.Some notable finding worth mentioning are:(a)heat source presence causes higher fluid velocity as compared to the heat sink;(b)all important surface shear stress can be suitably controlled,among others,by chemical reaction parameter and Schmidt number.The key challenge of this study has been to obtain exact closed-form solutions of the field equations,including cumbersome Laplace inverses.This study finds innovative applications in the emerging fields such as magnetic materials processing,chemical processes,solar energy systems,etc. 展开更多
关键词 Circular cylinder Hydromagnetic transient flow Chemical reaction Source/sink Free convection
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Post-adoption behaviour of farmers towards soil and water conservation technologies of watershed management in India
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作者 Gopal Lal Bagdi Prasanta kumar Mishra +7 位作者 Ravi Sankar Kurothe Swarn Lata Arya Shekhargouda Linganagouda Patil ashok kumar singh Bankey Bihari Om Prakash ashok kumar Palanisamy Sundarambal 《International Soil and Water Conservation Research》 SCIE CSCD 2015年第3期161-169,共9页
The Indian Institute of Soil and Water Conservation(IISWC)and its Research Centres have developed many successful model watershed projects in India in the past and implemented many Soil and Water Conservation(SWC)tech... The Indian Institute of Soil and Water Conservation(IISWC)and its Research Centres have developed many successful model watershed projects in India in the past and implemented many Soil and Water Conservation(SWC)technologies for sustainable watershed management.While many evaluation studies were conducted on these projects in the past,there has been no assessment of the post-adoption status of the SWC technologies over a longer period.It was imperative to appraise the behaviour of the farmers with regard to the continuance or discontinuance of the technologies adopted,diffusion or infusion that took place and technological gaps that occurred in due course of time in the post watershed programme.Therefore,it was realized that the postadoption behaviour of beneficiary farmers who have adopted different soil and water conservation technologies for watershed management projects should be studied in detail.The research study was initiated in 2012 as a core project at Vasad as the lead Centre along with IISWC headquarter Dehradun,and Centres Agra,Bellary,Chandigarh,Datia,Kota&Ooty,with the specific objectives of the study to measure the extent of post-adoption behaviour(continued-adoption,discontinuance,technological gap,diffusion and infusion)of farmers towards the adopted SWC technologies of watershed management.In the present study various indices regarding continued adoption,dis-adoption(discontinuance),technological gap,diffusion,infusion regarding soil and water conservation technologies for watershed management were developed for measurement of post-adoption behaviour of farmers.It was revealed that a little less than three-fourth(73%)of SWC technologies continued to be adopted and more than onefourth(27%)were discontinued by farmers.Out of the total continue adopted SWC technologies by farmers,a little less than onefifth(19%)of technologies continued to be adopted with a technological gap.More than one-fourth(28%)of SWC technologies were also diffused to other farmers’fields in nearby villages and on an average 1.2 technologies were also infused into the farmers'fields from outside by their own efforts in the watersheds developed by the IISWC and its Centres. 展开更多
关键词 Post-adoption Soil and water conservation Watershed Management
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