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Experimental study of the interspecific competition between two sibling marine herbivorous rotifers in relation to food availability and initial population density

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Acta Oceanologica sinica 2012年第4期31卷 113-126页

作者： divya s p Kathiresan K Asha p sekar V Rajasekaran R Centre of Advanced study in Marine Biology Faculty of Marine SciencesAnnamalai University school of Environmental studies Cochin University of Science and Technology

Our laboratory study concerns the competitive interaction between two marine rotifer species Bra- chionus plicatilis and Brachionus rotundiformis at five algal （ Nannochloropsis salina） concentrations （0.4＊106 to 32.4x106 cells/ml） and at four initial inoculation densities （numerically, 100% B. pli- catilis; 75% B. plicatilis and 25% B. rotundiforrnis, 50% each of the two species; 25% B. plicatilis and 75% B. rotundiformis and 100% B. rotundiforrnis. The initial biomass varied as 0.33 and 0.22 #g/ml for B. plicatilis and B. rotundiformis respectively. Experiments were performed at （25±1）C. population densities were enumerated and the medium was changed daily up to 8 d in the ex- periment. At the lowest food level tested, B. rotundiformis formed superior competitor than B. plicatilis, regardless of starting inoculation density. Generally when the food concentrations in- creased, B. plicatilis showed a greater increase in biomass than B. rotundiforrnis. B. rotundiformis formed the largest in population growth, regardless of increasing food concentrations. When grown alone, B. plicatilis reached peak abundances of （1.311 5±0.028） and （137.5±0.014） μg/ml at low and high food densities respectively. The corresponding values of B. rotundiformis were 0.724 5±0.016 and 18.15±0.021. The adverse effects of B. rotundiforrnis on the peak abundances of B. plicatilis were observed at the lowest food level and higher initial density. The rate of population growth in controls varied from （0.792±0.162） to （1.482±0.132） ttm/d for B. plicatilis and （0.445~0.041） to （0.856±0.012） μm/d for B. rotundiformis, depending on food level. When both species were intro- duced together, low food levels favoured higher abundance of B. rotundiforrnis than B. plicatilis, suggesting that increased population density of the smaller B. rotundiforrnis was more successfull than larger B. plicatilis in brackish waters. Our work reveals that available food （type and quan- tity） along with starting inoculat

关键词： competition food level B. plicatilis B. rotundiformis population density interspecificcompetition

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Nonlinear mixing-based terahertz emission in inclined rippled density plasmas

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Chinese physics B 2023年第6期32卷 384-390页

作者： K Gopal A p singh s divya Rajdhani College Department of Physics&ElectronicsUniversity of DelhiNew DelhiIndia Computational plasma Dynamics Laboratory Rajdhani CollegeDepartment of Physics&ElectronicsUniversity of DelhiNew DelhiIndia

We propose to investigate the THz field generation using nonlinear mixing mechanism of laser beat wave with inclined rippled density *** laser pulses with frequencies(ω_(1),ω_(2)) and wave vectors(k_(1),k_(2)) co-propagate and resultant laser beat wave forms at beat frequency(ω_(1)-ω_(2)).Laser beat wave imparts a nonlinear force on the ambient electrons and pushes them outward with nonlinear velocity v_(NL).Coupling of induced density perturbation and nonlinear velocity v_(NL)generates nonlinear currents at laser beat frequency that further generates electromagnetic field E_((ω_(1)-ω_(2))) in terahertz(THz)*** the present scheme,density ripples are introduced at an angle with respect to laser propagation and flat Gaussian index(f) is introduced in laser field profile that transform curved top of Gaussian field envelope into flat top field *** combined effect of flat laser pulses with inclined density ripples in plasmas shows 10-fold enhancement in THz field amplitude when flat-Gaussian index(f) varies from 1 to ***,the THz field intensifies when density ripples inclination increases upto a certain angle and then decreases.

关键词： terahertz inclined ripple flat laser laser plasma interaction

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Unlocking hypoglycemia–associated brain microvascular dysfunction:critical insights from proteomic analysis

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Neural Regeneration Research 2025年第6期20卷 1707-1708页

作者： siva s.V.p.sakamuri Anil sakamuri Department of Chemistry Auburn University at MontgomeryMontgomeryALUSA Vascular Biology Center and Department of Medicine Medical College of Georgia at Augusta UniversityAugustaGAUSA

Hypoglycemia-a critical complication linked to worsened brain function in diabetic subjects:Hypoglycemia is characterized by a decline in circulatory glucose levels below sta nda rd physiological *** hypoglycemia,classified as level 1 hypoglycemia,is defined by blood glucose levels below 70 mg/dL and can be effectively addressed through carbohydrate *** hypoglycemia,denoted by blood glucose levels less than 54 mg/dL,poses a life-threatening risk if left *** with type 1 and type 2 diabetes undergoing insulin treatment are particularly susceptible to hypoglycemia due to impaired counterregulatory mechanisms.

关键词： impaired intake critical

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Electronic and optical properties of TiO_2 and its polymorphs by Z-scan method

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Chinese physics B 2014年第8期23卷 340-344页

作者： s. divya V p N Nampoori p Radhakrishnan A Mujeeb International school of photonics Cochin University of Science and Technology

TiO2 is a material which has attracted considerable attention from the scientific community for its innumerable prop- erties. TiO2 is known to exist in nature in three different crystalline structures： rutile, anatase, and brookite. Anatase and rutile TiO2 films have been widely characterized for their potential applications in solar cells, self-cleaning coatings, and photocatalysis. In the present report, the third-order nonlinear susceptibilities of TiO2 and its polymorphs, anatase, and rutile, prepared by the sol-gel technique followed by heat treatment are investigated using the Z-scan technique at a wavelength of 532 nm with a duration of 7 ns. Imaginary and real values of Z（3） for amorphous, anatase, and rutile are also calculated and found to be 5 × 10^-19 m2/V2, 27 × 10^-19 m2/V2, 19 × 10^-19 m2/V2, respectively. It is found that the values of the optical constants of amorphous TiO2 after heat treatment vary considerably. It is assumed that this could be due to the variation in the electronic structure of TiO2 synchronous with the formation of its polymorphs, anatase, and rutile. Amorphous TiO2 is marked by the localization of the tail states near the band gap, whereas its crystalline counterparts are characterized by completely delocalized tail states.

关键词： excitons reverse saturable absorption (RsA) excitonic nonlinearity

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Intensity and composition-dependent sign reversal of non-linearity in TiO_2/CeO_2 nanocomposites

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Chinese physics B 2014年第3期23卷 298-302页

作者： s.divya V.p.N.Nampoori p.Radhakrishnan A.Mujeeb International school of photonics Cochin University of Science and Technology

CeO2/TiO2 composite nanoparticles with different Ce/Ti molar ratios have been successfully synthesized via sol-gel method. It was found that the band gap of the nanocomposite is tunable by varying Ce/Ti content. The nonlinear response of the sample was studied by using the nanosecond laser pulses from a Q switched Nd：Yag laser employing the Z-scan method. Open aperture Z-scan experiment revealed that with the increase in the CeO2 amount in the nanocomposite, the non-linearity of the composite increases, and it was assumed that this could be due to the modification of TiO2 dipole symmetry by the addition of CeO2. Closed aperture Z-scan experiment showed that when the CeO2 amount increases, positive nonlinear refraction decreases, and this could be attributed to the increase in the two photon absorption which subsequently suppresses the nonlinear refraction.

关键词： sol-gel method non-linearity Z-scan experiment reversesaturation absorption curve

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Tailoring optical properties of TiO_2 in silica glass for limiting applications

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Chinese physics B 2014年第3期23卷 303-307页

作者： s.divya Indu sebastian V.p.N.Nampoori p.Radhakrishnan A.Mujeeb International school of photonics Cochin University of Science and Technology

We present the linear and nonlinear optical studies on TiO2-siO2 nanocomposites with varying compositions. Opti- cal band gap of the material is found to vary with the amount of siO2 in the composite. The phenomenon of two-photon absorption （TpA） in TiO2/siO2 nanocomposites has been studied using open aperture Z-scan technique. The nanocom- posites show better nonlinear optical properties than pure TiO2, which can be attributed to the surface states and weak dielectric confinement of TiO2 nanoparticles by siO2 matrix. The nanocomposites are thermally treated and similar studies are performed. The anatase form of TiO2 in the nanocomposites shows superior properties relative to the amorphous and rutile counterpart. The involved mechanism is explained by rendering the dominant role played by the excitons in the TiO2 nanoparticles.

关键词： reverse saturable absorption (RsA) optical limiting excitons

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Investigating the fission dynamics of the following neutron shell closed nuclei within a stochastic dynamical approach:^(210)po,^(212)Rn,and ^(213)Fr

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Chinese physics C 2023年第3期47卷 127-137页

作者： divya Arora p.sugathan A.Chatterjee Inter-University Accelerator Centre Aruna AsafAli MargNew Delhi 110067India

The dissipative dynamics of nuclear fission is a well confirmed phenomenon that can be either described by a Kramers-modified statistical model or by a dynamical model employing the Langevin *** dynamical models as well as statistical models incorporating fission delays have been found to explain the measured fission observables in several studies,they present conflicting results for shell closed nuclei in the mass region of ***,an analysis of the recent data on neutron shell closed nuclei in the excitation energy range of 40-80 MeV failed to provide a satisfactory description of the data,which was attributed to a mismatch with shell effects and/or entrance channel effects,without reaching a definite *** the present study,we demonstrate that a well established stochastic dynamical code can simultaneously reproduce the available data for pre-scission neutron multiplicities and fission and evaporation residue excitation functions for the following neutron shell closed nuclei^(210)po and^(212)Rn and their isotopes^(206)po and^(214,216)Rn without the need for including any extra shell or entrance channel *** relevant calculations are performed by using a phenomenological universal friction form factor with no ad-hoc adjustment of the model ***,we note a significant deviation,beyond experimental errors,for some Frisotopes.

关键词： fusion-fission nuclear dissipation dynamical model neutron shell closure saddle shell corrections

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INITIAL BOUNDARY VALUE pROBLEM FOR A NONCONsERVATIVE sYsTEM IN ELAsTODYNAMICs

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Acta Mathematica scientia 2018年第3期38卷 1043-1056页

作者： K.divya JOsEpH p.A.DINEsH Department of Mathematics M.s.Ramaiah Institute of Technology MsRIT p.O Department of Mathematics M.S.Ramaiah Institute of Technology MSRIT P.O

This article is concerned with the initial boundary value problem for a nonconservative system of hyperbolic equation appearing in elastodynamics in the space time domain x 〉 0, t 〉 0. The number of boundary conditions, to be prescribed at the boundary x = 0,depends on the number of characteristics entering the domain. Because our system is nonlinear, the characteristic speeds depends on the unknown and the direction of the characteristics curves are known apriori. As it is well known, the boundary condition has to be understood in a generalised way. One of the standard way is using vanishing viscosity method. We use this method to construct solution for a particular class of initial and boundary data, namely the initial and boundary datas that lie on the level sets of one of the Riemann invariants.

关键词： Elastodynamics viscous shocks

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Constrained controllability of nonlinear neutral fractional integrodifferential systems

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Journal of Control and Decision 2017年第2期4卷 81-99页

作者： s.divya K.Balachandran Department of Mathematics Bharathiar UniversityCoimbatoreIndia

In this paper,we study the complete controllability for a class of nonlinear neutral fractional integro-differential systems in a finite interval of time by means of controls whose initial and final values can be assigned in *** result is achieved using the Banach fixedpoint theorem and schauder’s fixed-point *** numerical examples are provided to demonstrate the effectiveness of the main result.

关键词： Constrained controllability neutral fractional integrodifferential equations fixed point theorem

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Bearing capacity of foundations on rock slopes intersected by non-persistent discontinuity

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International Journal of Mining science and Technology 2020年第5期30卷 669-674页

作者： divya shaunik Mahendra singh Department of Civil Engineering Indian Institute of Technology RoorkeeRoorkee 247667India

Rocks encountered in foundations of heavy structures are invariably intersected by discontinuities(joints).In the past,several studies have been performed by researchers to incorporate the effect of fully persistent joints in the assessment of the load-carrying capacity of ***,in the field,the joints are non-persistent,and an assumption of full persistency will underestimate the ***,shaunik&singh have studied the influence of non-persistency,number of joint segments and discontinuity orientation on the strength behaviour of rock specimens(shaunik and singh,2019).Bell’s approach can be used to obtain the bearing capacity of shallow foundations placed in jointed *** the present study,results of the experimental work(shaunik and singh,2019)conducted by shaunik&singh have been used to suggest expressions by extending Bell’s approach for computing bearing capacity of the foundation placed near the crown of a rock *** to use design charts are also presented for field ***,a real-life problem from Indian Garhwal Himalayas is considered,and the approach suggested in this study is utilised to obtain the bearing capacity of a bridge foundation as a function of uniaxial compressive strength(UCs)of intact rock,joint friction,spacing and orientation of joint,nonpersistency and number of joint segments.

关键词： Uniaxial compressive strength(UCs) Joint segment Discontinuity Non-persistency Bell’s approach

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