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The effect of interference time in a predator–prey–nonprey system

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International Journal of Modeling, Simulation, and Scientific Computing 2022年第3期13卷 230-244页

作者： debasis mukherjee Department of Mathematics Vivekananda College ThakurpukurKolkata 700063India

In this paper,we propose a three-species model consisting of two competing(prey and nonprey)species and a predator ***,nonprey species are not included in the predator’s food *** competition process follows Holling type II competitive response to interference *** results include the stability of the ***,it is established that an increasing number of interference time stabilizes the ***,it is shown that the interference time has an impact on the predator equilibrium ***,we develop the criterion of persistence of all the *** is also shown that the system may not be persistent when multiple steady states *** examine the global stability of the coexistence equilibrium *** experiments are carried out to understand the analytical outcomes.

关键词： Interference time predator-prey-nonprey interaction stability bifurcation persistence

Chaos to order： Effect of random predation in a Holling type IV tri-trophic food chain system with closure terms

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International Journal of Biomathematics 2016年第5期9卷 153-170页

作者： Partha Ghosh Pritha Dast debasis mukherjee Department of Mathematics Indian Institute of Engineering Science and Technology Shibpur Howrah 711103 India Department of Mathematics Vivekananda College Thakurpukur Kolkata 700063 India

Complex dynamics of modified Hastings-Powell （HP） model （phytoplankton-zoo- plankton-fish） with Holling type IV functional response and density-dependent morta- lity （closure terms） for top predator species is investigated in this paper. Closure terms describe the mortality of top predator in plankton food chain models. Modified HP model with Holling type IV functional response gives rise to similar type of chaotic dynamics （inverted ＂teacup attractor＂） as observed in original HP model with Holling type II functional response. It is observed that introduction of nonlinear closure terms eliminate chaos and system dynamics becomes stable. Observation of this paper support the ＂Steele-Henderson conjecture＂ that, nonlinear closure terms eliminate or reduces limit cycles and chaos in plankton food chain models. Chaotic or stable dynamics are numerically verified by Lyapunov exponents （LE） method and Sil＇nikov eigenvalue anal- ysis and also illustrated graphically by plotting bifurcation diagrams. It is assumed that mortality of fish population, caused by higher-order predators （which are not explicitly included in the model） is not constant, rather it exhibits random variation through- out the year. To incorporate the effect of random mortality of fish population, white noise term is introduced into the original deterministic model. It is observed that the corresponding stochastic model is stable in mean square when the intensity of noise is small. Keywords： Holling type IV; chaos; closure term; white noise; mean square stability

关键词：随机变化 HollingⅡ型功能性反应食物链系统封闭捕食效应 Lyapunov指数食物链模型均方稳定性

Fluctuating Role of Parameters in the Analysis of the Continues and Discrete Version of a Susceptible-Incubated-Infected Model

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International Journal of Modern Nonlinear Theory and Application 2012年第2期1卷 47-50页

作者： Prasenjit Das debasis mukherjee Kalyan Das A. Sabarmathi Baikunthapur High School Maipith India Department of Mathematics National Institute of Food Technology Entrepreneurship and Management HSIIDC Industrial Estate Kundli India Department of Mathematics School of Advanced Sciences VIT University Vellore India Department of Mathematics Vivekananda College Kolkata India

The article concentrates on the role of fluctuating parameters for removable population from the incubated class in a susceptible-incubated-infected model. The discrete analogous of this model is also investigated. Conditions for local asymptotic stability are derived for both the disease free and endemic cases. Numerical simulations are performed to validate the theoretical results.

关键词： Incubated Class Stability Schur-Cohn Criterion

A simple chemical method for the synthesis of Cu^(2+) engrafted MgAl_(2)O_(4) nanoparticles: Efficient fluoride adsorbents, photocatalyst and latent fingerprint detection

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Journal of Environmental Sciences 2020年第2期32卷 301-315页

作者： Arnab mukherjee Mrinal KAdak Prasanta Dhak debasis Dhak Nanomaterials Research Lab Department of ChemistrySidho-Kanho-Birsha UniversityPurulia 723104India Department of Chemistry Techno India UniversityKolkata 700091India

An adaptable, energy efficient chemical process is employed to synthesize Cu^2+engrafted MgAl2O4 nanoparticles(Mg1-xCuxAl2O4, x = 0, 0.1, 0.3, 0.5 abbreviated as MCA0, MCA1, MCA3,and MCA5 respectively), using chelating ligand and the calcination temperature was determined by the thermogravimetric analysis of the precursor *** acted as good fluoride adsorbent in the presence of co-ions, different pH(2–11) via chemisorption revealed from Fourier-transform infrared spectroscopy(FTIR) and photodegraded Methylene Blue(MB).The satisfactory results were for MCA1(specific surface area 25.05 m^2/g) with 97%fluoride removal at pH 7.0 for the 10 mg/L initial fluoride concentration for 1.5 g/L adsorbent dose with 45 min contact time obeying the Langmuir isotherm model with negative thermodynamic parameters and 4 mmol of MCA3 with 98.51% photodegradation for 10-5 mol/L MB solution obeying pseudo-second-order and pseudo-first-order kinetics *** proposed photodegradation mechanism of MB was established by the FTIR and high-performance liquid chromatography(HPLC) *** nanoparticles are cubic, estimated through X-ray diffraction(XRD) and transmission electron microscopy(TEM) *** band gap energies, grain size, and the effective working pH were estimated by diffuse reflectance spectra(DRS), scanning electron microscope(SEM), and zero-point potential analysis respectively.A soil candle with MCA1 also fabricated for the household purpose and tested with some fluorinated field *** MCA3 was able to enhance the latent fingerprint on smooth surfaces.

关键词： Fluoride adsorbent Photocatalysis Mechanism Fingerprint detection Kroger-Vink notation Soil candle

An approach towards estimating critical value of waiting time at transit stops

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Journal of Traffic and Transportation Engineering(English Edition) 2021年第2期8卷 257-266页

作者： Subhojit Roy debasis Basu School of Infrastructure Indian Institute of Technology BhubaneswarOdisha 752050India

Waiting time at transit stops is found to be an influential policy variable for a passenger’s decision on whether to undertake a given transit service. With regard to policy framework for improvement of operational service headway of a transit service and thereby its waiting time, the necessity to have knowledge on its critical value becomes inevitable. The critical value of waiting time for passengers waiting at transit stops is that duration beyond which passengers are found to be no more interested to wait for a that transit service. The paper demonstrates an approach for estimating the critical value of waiting time at urban transit stops with reference to public transport services such as city bus and shared-auto operational in Bhubaneswar, India. The critical value of waiting time is estimated from the point on cumulative distribution curve of waiting time frequency distribution, at which the maximum rate of change of the slope of curve occurs. The work assumes two positively skewed distributions such as gamma and log-normal for observed distributional pattern of waiting time. The work identifies that gamma distribution is comparatively fitting the observed data better than log-normal distribution. The study reveals that the critical value of waiting time for city bus passengers is about twice than that of shared auto ***, the study presents new information on critical values of waiting time with reference to an urban area of a developing country, it also demonstrates an experience on application of probability distribution functions for understanding distributional pattern of waiting time.

关键词： Traffic engineering Waiting time at transit stop Critical value of waiting time Probability density function Gamma and log-normal distribution

Bayesian inference and life testing plans for generalized exponential distribution

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Science China Mathematics 2009年第6期52卷 1373-1388页

作者： KUNDU debasis PRADHAN Biswabrata Department of Mathematics and Statistics Indian Institute of Technology KanpurKanpur 208016India Statistical Quality Control & Operations Research Unit Indian Statistical Institute203 B.T.RoadKolkata700108India

Recently generalized exponential distribution has received considerable attentions. In this paper, we deal with the Bayesian inference of the unknown parameters of the progressively censored generalized exponential distribution. It is assumed that the scale and the shape parameters have independent gamma priors. The Bayes estimates of the unknown parameters cannot be obtained in the closed form. Lindley’s approximation and importance sampling technique have been suggested to compute the approximate Bayes estimates. Markov Chain Monte Carlo method has been used to compute the approximate Bayes estimates and also to construct the highest posterior density credible intervals. We also provide different criteria to compare two different sampling schemes and hence to find the optimal sampling schemes. It is observed that finding the optimum censoring procedure is a computationally expensive process. And we have recommended to use the sub-optimal censoring procedure, which can be obtained very easily. Monte Carlo simulations are performed to compare the performances of the different methods and one data analysis has been performed for illustrative purposes.

关键词： shape parameter scale parameter Markov Chain Monte Carlo importance Sampling fisher information matrix 62F15 62F10 62F99

Design of crown pillar thickness using finite element method and multivariate regression analysis

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International Journal of Mining Science and Technology 2017年第6期27卷 955-964页

作者： Kumar Hemant Deb debasis Chakravarty D. Department of Mining Engineering Indian Institute of Technology (Indian School of Mines) Dhanbad 826004 India Department of Mining Engineering Indian Institute of Technology Kharagpur 721302 India

Minerals are now being extracted from deep mines due to drying up of resource in shallow ground. The need for suitable supports and ground control mechanisms for safe mining necessitates proper pillar design with filling technology. In addition, high horizontal stress may cause collapse of hanging wall and footwall rocks, hence designing of suitable crown pillars is absolutely necessary for imposing overall safety of the stopes. This paper provides a methodology for the evaluation of the required thickness of crown pillars for safe operation at depth ranging from 600 m to 1000 m. Analyses are conducted with the results of 108 non-linear numerical models considering Drucker-Prager material model in plane strain condition. Material properties of ore body rock and thickness of crown pillars are varied and safety factors of pillars estimated. Then, a generalized statistical relationship between the safety factors of crown pillars with the various input parameters is developed. The developed multivariate regression model is utilized for generating design/stability charts of pillars for different geo-mining *** design charts can be used for the design of crown pillar thickness with the depth of the working,taking into account the changes of the rock mass conditions in underground metal mine.

关键词： Cut and fill mining Crown pillar FEM Regression model Design chart

Non-Classical Hodgkin＇s Lymphoma Presenting As Cauda Equina Syndrome a Rare presentation： One Case Report

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Clinical oncology and cancer researeh 2010年第5期7卷 322-325页

作者： Pradipta Guha debasis Sarkar Indranil Thakur Partha Sardar Sekhar mukherjee Sanjoy Kumar Chatterjee Department of cardiology G.B.Pant HospitalNew Delhi Jawaharlal Nehru Marg 110002New Delhi India. Department of General Medicine Medical College Kolkata 88 College Street Kolkata 700073 West Bengal India. Department of General Medicine Lal Bahadur Shastri Hospital Khichripur New Delhi 110091 India.

Nodular lymphocyte predominant Hodgkin＇s disease occurs in 5% of all cases of Hodgkin＇s disease. It occurs more commonly in male. Only 5% of all Hodgkin＇s lymphoma cases develop spinal cord compression and in only 0.2% cases, spinal cord compression occurs as the initial presentation. So our case is rare both in the form of the unique variety of Hodgkin＇s disease and also in the form of presentation.

关键词： Hodgkin's disease non-classical variety cauda equina syndrome.

Enantioselective iridium-catalyzed allylic substitution with a Reformatsky reagent: direct construction of β-stereogenic homoallylic esters

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Science China Chemistry 2024年第11期67卷 3791-3797页

作者： debasis Pal Kirana DVeeranna Yuk Fai Wong PAndrew Evans Department of Chemistry Queen’s University90 Bader LaneKingstonK7L 3N6Canada Xiangya School of Pharmaceutical Sciences Central South UniversityChangsha410013China

The Reformatsky reagent derived from ethyl bromoacetate circumvents the challenge associated with the direct regio-and enantioselective iridium-catalyzed allylic alkylation with an unstabilized aliphatic ester enolate. Notably, this work represents the first example of using a Reformatsky reagent in a metal-allyl reaction, which permits the direct construction of enantioenriched β-stereogenic homoallylic esters without preactivation of the pronucleophile or post-reaction modification of the product(e.g., thermal decarboxylation of a 1,3-dicarbonyl). Moreover, the process allows the coupling of a broad range of sterically and electronically diverse electrophiles bearing aryl, heteroaryl and alkenyl derivatives, including the significantly more challenging alkyl-substituted allylic carbonates. The versatility of the ester product is exemplified by a series of functional group manipulations and the development of a concise and efficient enantioselective total synthesis of the natural product,(+)-descurainolide A. Finally, mechanistic studies indicate that the zinc enolate behaves as a soft nucleophile that undergoes outer-sphere alkylation.

关键词： allylic substitution asymmetric catalysis mechanistic studies natural product synthesis Reformatsky reagent