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Switching effect on a two prey-one predator system with strong Allee effect incorporating prey refuge

International Journal of Biomathematics 2024年第2期17卷 1-50页

作者： sangeeta saha Guruprasad Samanta Department of Mathematics Indian Institute of Engineering Science and Technology Shibpur Howrah 711103India

In an environment,the food chains are balanced by the prey-predator *** a predator species is provided with more than one prey population,it avails the option of prey switching between prey species according to their ***,prey switching of predators mainly helps to increase the overall growth rate of a predator *** this work,we have proposed a two prey-one predator system where the predator population adopts switching behavior between two prey species at the time of *** the prey population exhibit a strong Allee effect and the predator population is considered to be a generalist *** proposed system is biologically well-defined as the system variables are positive and do not increase abruptly with *** local stability analysis reveals that all the predator-free equilibria are saddle points whereas the prey-free equilibrium is always *** intrinsic growth rates of prey,the strong Allee parameters,and the prey refuge parameters are chosen to be the controlling parameters *** numerical simulation reveals that in absence of one prey,the other prey refuge parameter can change the system dynamics by forming a stable or unstable limit ***,a situation of bi-stability,tri-stability,or even multi-stability of equilibrium points occurs in this *** in presence of the switching effect,the predator chooses prey according to their abundance,so,increasing refuge in one prey population decreases the count of the second prey *** is also observed that the count of predator population reaches a comparatively higher value even if they get one prey population at its fullest quantity and only a portion of other prey ***,in the scarcity of one prey species,switching to the other prey is beneficial for the growth of the predator population.

关键词： Prey-predator model switching effect strong Allee effect prey refuge

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Analysis of a predator-prey model with herd behavior and disease in prey incorporating prey refuge

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International Journal of Biomathematics 2019年第1期12卷 133-171页

作者： sangeeta saha G.P.Samanta Department of Mathematics Indian Institute of Engineering Science and Technology Shibpur Howrah-711103India

In this work,we have introduced an eco-epidemiological model of an infected predator prey *** of prey refuge gives that a fraction of the infected prey is available to the predator for ***,to make the model more realistic to the environment,we have introduced strong Allee effect in the susceptible *** and positivity of the solution have been *** stability conditions of the equilibrium points have been found with the help of Routh-Hurwitz criterion and it has been observed that if a prey population is infected with a lethal disease,then both the prey(susceptible and infected)and predator cannot survive simultaneously in the system for any parametric *** disease transmission rate and the attack rate on the susceptible have an important role to control the system *** different values of these two key parameters,we have got only healthy or disease-free or predation-free or a fluctuating disease-free or even a fluctuating predator-free system with some certain parametric conditions.

关键词： Allee effect herd behavior infected prey refuge extinction bifurcations

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Nucleus accumbens receives gastric vagal inputs

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Acta Pharmacologica Sinica 2004年第3期25卷 17-21页

作者： sangeeta MEHENDALE Department of Anesthesia & Critical Care IL 60637 The Pritzker School of Medicine The University of Chicago USA and Tang Center for Herbal Medicine Research

AIM: To localize and characterize the response of single accumbal neurons to electrical stimulation of the gastric vagal fibers. METHODS: Unitary responses to electrical stimulation of the ventral and dorsal gastric vagal fibers which serve the proximal stomach were recorded extracellularly in the nucleus accumbens in anesthetized cats. RESULTS: The evoked units recorded in the nucleus accumbens consisted of phasic and tonic responses, with a mean latency of (396±43) ms. Convergence of ventral and dorsal gastric vagal inputs onto single phasic and tonic accumbal units was observed. For tonic inhibitory responses, convergence was exhibited when stimulation applied to both the ventral and dorsal gastric vagal branches resulted in a significantly longer inhibitory period than did stimulation of a single gastric vagal branch. Comparing the gastric vagally evoked accumbal unitary responses to the neuronal responses recorded in the nucleus tractus solitarius, parabrachial nucleus and hypothalamus in our previous studies, our data showed a higher percentage of single spike responses and shorter response duration’s in the nucleus accumbens than in the other nuclei. This suggests that the synaptic drive from the gastric vagal inputs to the nucleus accumbens is less powerful than in the other structures. CONCLUSION: The present study localized and characterized gastric vagally evoked responses in the nucleus accumbens, which suggest that the nucleus accumbens may process gastric signals concerned with the ingestive process.

关键词： nucleus accumbens unitary response,electrical stimulation vagus nerve stomach

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Syntrophic co-culture of Bacillus subtilis and Klebsiella pneumonia for degradation of kraft lignin discharged from rayon grade pulp industry

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Journal of Environmental Sciences 2015年第7期27卷 229-238页

作者： sangeeta Yadav Ram Chandra Department of Environmental Microbiology School for Environmental Sciences Babasaheb Bhimrao Ambedkar University (A Central University)

In order to search the degradability of kraft lignin, the potential bacterial strains Bacillus subtilis（GU193980） and Klebsiella pneumoniae（GU193981） were isolated, screened and applied in axenic and co-culture conditions. Results revealed that mixed culture showed better decolorization efficiency（80%） and reduction of pollution parameters（COD 73% and BOD62%） than axenic culture. This indicated syntrophic growth of these two bacteria rather than any antagonistic effect. The HPLC analysis of degraded samples of kraft lignin has shown the reduction in peak area compared to control, suggesting that decrease in color intensity might be largely attributed to the degradation of lignin by isolated ***, the GC-MS analysis showed that most of the compounds detected in control were diminished after bacterial treatment. Further, the seed germination test using Phaseolus aureus has supported the detoxification of bacterial decolorized kraft lignin for environmental safety. All these observations have revealed that the developed bacterial co-culture was capable for the effective degradation and decolorization of lignin containing rayon grade pulp mill wastewater for environmental safety.

关键词： Degradation GC-MS Kraft lignin Seed germination test Syntropic

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Effect of heavy metals and phenol on bacterial decolourisation and COD reduction of sucrose-aspartic acid Maillard product

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Journal of Environmental Sciences 2013年第1期25卷 172-180页

作者： sangeeta Yadav Ram Chandra Department of Environmental Microbiology School for Environmental SciencesBabasaheb Bhimrao Ambedkar University (A Central University)

Melanodins are amino-carbonyl complex, predominantly present in sugarcane molasses based distillery wastewater as major source of colourant. The microbial decolourisafion of melanoidin is a challenge due to its binding property with other co-pollutants of distillery waste. Results revealed that the presence of Zn2＋（2.00-20.00 mg/L） in melanoidin solution （1200 mg/L） stimulated the bacterial growth and sucrose-aspartic acid Maillard product （SAA） decolourisation as compared to control, while Fe3＋ and Mn2＋ at the same concentration inhibited the process. However, the presence of phenol （100 mg/L） along with Zn2＋, Fe3＋ and Mn2＋ suppressed the bacterial growth, SAA decolourisation and MnP activity. The shrinkage and reduced number of bacterial cell count at higher concentration of heavy metals in presence of phenol was also observed under scanning electron microscope.

关键词： degradation manganese peroxidase melanoidin

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Preparation of LDPE-Acetylated/Butyrylated Starch Blend Blow Films and Characterization

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Chinese Journal of Polymer Science 2014年第3期32卷 268-279页

作者： sangeeta Garg Asim Kumar Jana Department of Chemical Engineering National Institute of TechnologyJalandhar Department of Biotechnology National Institute of TechnologyJalandhar

Development of modified plastics has been studied through the LDPE-acylated starch blend films to examine the effect of different acyl groups and degrees of substitution （DS） on properties of films. Corn starch was modified with acetyl and hutyryl groups and films were prepared by blending acylated starch with low density polyethylene （LDPE）. Systematic studies were done to observe the effect of acyl groups, DS and starch concentration on the properties and biodegradability of the blend films. It was observed that blend films containing 5% acetylated and butyrylated starches of high DS （2.5, 1.7） maintained 75% and 83% of tensile strength of LDPE films. Thermal analysis results indicated that acetylated and butyrylated starch blend films decomposed at 370℃ and 389℃ which were higher than the decomposition temperature of native starch film （349℃）. Scanning electron micrographs of blend films containing high DS acylated starch showed well dispersed starch particles due to improvement in dispersion between starch and LDPE. Water absorption capacity of high DS acetylated and butyrylated starch blend films （4.18% and 3.76%, respectively） was lower than that of native starch films （5%）. This study has an advantage because of blown films prepared can be integrated with the present manufacturing systems without any other requirement.

关键词： Acylated starch LDPE-starch blend films Mechanical properties Water absorption capacity Biodegradability.

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Influence of anthropogenic activities on landslide susceptibility:A case study in Solan district,Himachal Pradesh,India

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Journal of Mountain Science 2023年第2期20卷 429-447页

作者： sangeeta S.K.SINGH Department of Civil Engineering Punjab Engineering CollegeChandigarh 16012India

Landslides in the Himalayan region are primarily controlled by natural parameters,including rainfall,seismic activity,and anthropogenic parameters,such as the construction of large-scale projects like road development,tunneling and hydroelectric power projects and climate *** parameters which are more crucial among these are a matter of scientific study and *** research,taking Solan district,Himachal Pradesh,India,as the study area,aims to assess the impact of anthropogenic activities on landslide susceptibility at a regional *** distribution was characterized into two groups,namely Rainfall-Induced Landslide(RIL)and Human-Induced Landslide(HIL)based on triggering *** data such as slope angle,aspect,profile curvature,distance to drainage,distance to lineament,lithology,distance to road,normalized difference vegetation index(NDVI)and land use land cover(LULC)have been considered for delineating the landslide susceptibility zonation(LSZ)*** effect of anthropogenic activities on landslide occurrences has been examined through the distribution of landslides along national highways and land use land cover changes(LULCC).Two sets of LSZ maps with a LULC of time interval covering five years(2017&2021)were prepared to compare the temporal progression of LULC and landslide susceptibility during the five *** results indicated the significant impact of anthropogenic activities on the landslide *** map of the year 2021 shows that 23%area falls into high and very high susceptible classes and 48%area falls into very low and low susceptibility *** to LSZ map of 2017,high and very high susceptible classes have been increased by 15%,whereas very low and low susceptible classes have been reduced by 7%.The present case study will help to understand the potential driving parameters responsible for HIL and also suggest the inclusion of LULC in landslide susceptibility *** study will demonstrate new

关键词： Landslide Anthropogenic Human-Induced Landslide(HIL) Rainfall-Induced Landslide(RIL)

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Polynomial friction pendulum isolators(PFPIs)for seismic performance control of benchmark highway bridge

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Earthquake Engineering and Engineering Vibration 2017年第4期16卷 827-840页

作者： Arijit saha Pumachandra saha Sanjaya Kumar Patro School of Civil Engineering KIlT UniversityBhubaneswarOdishaIndia

The seismic response of a benchmark highway bridge isolated with passive polynomial friction pendulum isolators （PFPIs） is investigated and subjected to six bidirectional ground motion records. The benchmark study is based on a lumped mass finite-element model of the 91/5 highway overcrossing located in Southern California. The PFPI system possesses two important parameters; one is horizontal flexibility and the other is energy absorbing capacity through friction. The evaluation criteria of the benchmark bridge arc analyzed considering two parameters, time period of the isolator and coefficient of friction of the isolation surface. The results of the numerical study are compared with those obtained from the traditional friction pendulum system （FPS）. Dual design performance of the PFPI system suppressed the displacement and acceleration response of the benchmark highway bridge. The dual design hysteresis loop of the PFPI system is the main advantage over the linear hysteresis loop of the FPS. The numerical result indicates that the seismic performance of the PFPI system is better than that of the traditional FPS isolated system. Further, it is observed that variations of the isolation time period and coefficient of friction of the FPS and PFPI systems have a significant effect on the peak responses of the benchmark highway bridge.

关键词： benchmark highway bridge seismic isolation FPS PFPI evaluation criteria

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Petrography and tectonic provenance of the Miocene Surma Group in parts of the Naga-Manipur hills, in and around Nungba,Northeast India

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Acta Geochimica 2019年第6期38卷 834-847页

作者： Angom sangeeta NPandey Oinam Kingson Department of Earth Science Assam UniversitySilchar 788011India Department of Earth Science Pondicherry UniversityPuducherry 605014India

The Miocene molassic Surma sandstones in parts of the Naga-Manipur hills,in and around Nungba,Northeast India have been studied for their tectonic provenance using petrography and heavy mineral *** poorly-to-moderately-sorted sub-litharenite to lithicarkose type Surma sandstones display predominance of monocrystalline quartz(av.61%)and include undulose and non-undulose varieties and almost equal amounts of feldspars(av.22%)and rock fragments(av.17%).The heavy mineral suite of Surma sandstones is dominated by transparent varieties(96%)that include garnet,zircon,tourmaline,rutile,staurolite,scapolite,phlogopite,chondrodite,humite,wollastonite,hedenbergite,sphene,chlorite,sillimanite,glauconite,glaucophane,and *** heavy minerals characterize the granitic and silicic metamorphic complexes(GM)as well as the basic metamorphic rocks(MT)like greenstones,green schist,and amphibolites relating to passive continental margin *** opaque grains constitute nearly 4%of the total heavy *** presence of euhedral,as well as abraded heavy mineral grains,further supports a mixed provenance having substantial contribution from sedimentary and metamorphic rocks.A ZTR index of approximately 45%indicates mineralogically sub-mature nature of Surma *** on the light and heavy mineral suites coupled with the type of terrain available in the vicinity of the study area,it may be visualized that the sediment supply was largely made by the Himalaya,the IMR,the Shillong plateau,and the Mikir Hills under the influence of semi-arid to semi-humid climatic *** overall supply from a recycled orogen provenance has been envisaged.

关键词： Petrography Tectonic provenance Miocene Surma Group Naga-Manipur hills Nungba,Northeast India

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Effect of tool rotational speed on the particle distribution in friction stir welding of AA6092/17.5 SiCp-T6 composite plates and its consequences on the mechanical property of the joint

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Defence Technology（防务技术） 2020年第2期16卷 381-391页

作者： Uttam Acharya Barnik saha Roy Subhash Chandra saha Department of Mechanical Engineering National Institute of Technology AgartalaBarjalaJiraniaWest Tripura799046India

This study investigates the effect of tool rotational speed(TRS)on particle distribution in nugget zone(NZ)through quantitative approach and its consequences on the mechanical property of friction stir welded joints of AA6092/17.5 SiCp-T6 composite.6 mm thick plates are welded at a constant tool tilt angle of 2°and tool traverse speed of 1 mm/s by varying the TRS at 1000 rpm,1500 rpm and 2000 rpm with a taper pin profiled *** analysis shows large quantity of uniformly shaped smaller size SiC particle with lower average particle area which are homogeneously distributed in the *** fragmentation of bigger size particles has been observed because of abrading action of the hard tool and resulting shearing effect and severe stress generation due to the rotation of *** particles occupy maximum area in the matrix compared to that of the base material(BM)due to the redistribution of broken particles as an effect of *** migration of particles towards the TMAZ-NZ transition zone has been also encountered at higher TRS(2000 rpm).The microhardness analysis depicts variation in average hardness from top to bottom of the NZ,minimum for 1500 rpm and maximum for 2000 *** impact strength at 1000 rpm and 1500 rpm remains close to that of BM(21.6 J)while 2000 rpm shows the accountable *** maximum joint efficiency has been achieved at 1500 rpm(84%)and minimum at 1000 rpm(68%)under tensile *** analysis shows mixed mode of failure for BM,1000 rpm and 1500 rpm,whereas 2000 rpm shows the brittle mode of failure.

关键词： Friction stir welding Aluminium matrix composite Tool rotational speed Particle distribution Mechanical property

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