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

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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

On the Geometry of the Anti-canonical Bundle of the Bott–Samelson–Demazure–Hansen Varieties

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Acta Mathematica Sinica,English Series 2024年第8期40卷 1920-1940页

作者： Indranil BISWAS S.Senthamarai KANNAN Pinakinath saha School of Mathematics Tata Institute of Fundamental Research1 Homi Bhabha RoadMumbai 400005India Chennai Mathematical Institute Plot H1SIPCOT IT ParkSiruseriKelambakkam603103India

Let G be a semi-simple simply connected algebraic group over the field C of complex *** T be a maximal torus of G,and let W be the Weyl group of G with respect to *** Z(w,i)be the Bott–Samelson–Demazure–Hansen variety corresponding to a tuple i associated to a reduced expression of an element w∈*** prove that for the tuple i associated to any reduced expression of a minuscule Weyl group element w,the anti-canonical line bundle on Z(w,i)is globally *** consequence,we prove that Z(w,i)is weak *** that G is a simple algebraic group whose type is different from *** S={α1,...,αn}be the set of simple *** w be such that support of w is equal to *** prove that Z(w,i)is Fano for the tuple i associated to any reduced expression of w if and only if w is a Coxeter element and w^(−1)(Σ_(t=1)^(n)α_(t))∈−S.

关键词： Bott-Samelson-Demazure-Hansen variety Coxeter element anti-canonical line bundle Fano weak Fano

Painlevéintegrability,auto-Bäcklund transformations,new abundant analytic solutions including multi-soliton solutions for time-dependent extended KdV8 equation in nonlinear physics

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Journal of Ocean Engineering and Science 2024年第5期9卷 489-507页

作者： Shailendra Singh S.saha Ray National Institute of Technology Department of MathematicsRourkela 769008India

In this paper,a new eighth-order(1+1)-dimensional time-dependent extended KdV equation has been *** considered equation is being found completely integrable by using the Painlevéanalysis ***,three auto-Bäcklund transformations have been generated by truncating the Painlevéseries at a constant *** auto-Bäcklund transformations have been used to derive various analytic solution families for the newly developed *** solutions include the kink-antikink soliton,kink-soliton,antikink-soliton,periodic-soliton,complex kink-soliton and complex periodic-soliton ***-soliton solutions including N-soliton solution,have been obtained by using the simplified Hirota’s method for the considered *** the results are being expressed graphically to signify the physical importance of the considered equation.

关键词： Higher-order KdV equation Painlevéanalysis Auto-Bäcklund transformation Simplified Hirota method

The resource-based Kuznets curve hypothesis:An empirical exploration

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Geoscience Frontiers 2024年第5期15卷 162-173页

作者： Mehmet Akif Destek Tanaya saha Gamze Destek Avik Sinha Department of Economics Gaziantep UniversityGaziantepTurkey Research Methods Application Center of UNEC Azerbaijan State University of Economics(UNEC)Baku AZ1001Azerbaijan General Management and Economics Goa Institute of ManagementIndia Adnan Kassar School of Business Lebanese American UniversityBeirut 1102-2801Lebanon Management Development Institute Gurgaon India

Countries face the risk of natural resource curse because of making their economic growth excessively dependent on natural *** excessive resource dependence causes such a risk,it is inevitable that resource-rich countries will need resource rent up to a certain level of economic *** the other hand,transferring the wealth achieved after this maturity level to productive investment areas also reduces the resource dependency levels of *** this context,countries that capture the possible inverted U-shaped relationship between economic growth and resource dependence can escape the *** on this,the aim of this research is to determine the validity of the Kuznets type relationship between resource dependence and economic growth for the first time in the *** nations that rely heavily on natural resources are used as a sample for *** countries with a share of total resource rent in national revenue greater than 25%are taken into consideration throughout the selection process for these *** novel panel data methodologies,the effects of capital accumulation,public spending,foreign direct investment,and economic growth on the dependence on natural resources is examined from 1993 to *** results reveal that capital accumulation reduces resource dependency while foreign investments and government size increases *** addition,the Resource-Based Kuznets curve concept is supported by empirical data demonstrating an inverted-U-shaped relationship between economic growth and resource dependence for these *** thresholds derived from the parameters show that Saudi Arabia and Kazakhstan are well beyond this *** Democratic Republic of the Congo and the Republic of the Congo,on the other hand,remain a long way from this ***,Iraq,Mongolia,Iran,and Azerbaijan have national incomes that are close at the threshold.

关键词： Resource-based Kuznets curve Economic growth Natural resources Foreign direct investment Government size

Assessment of coastal and mangrove vulnerability in the Andaman Island,Indian Ocean

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Geoscience Frontiers 2024年第5期15卷 47-60页

作者： Biswajit Mondal Rupesh K.Bhomia Ashis Kumar saha Richard A.MacKenzie Department of Geography Delhi School of EconomicsUniversity of DelhiDelhi 110007India Centre for International Forestry Research(CIFOR) Jalan CIFORSitu GedeBogor BaratBogor 16115Indonesia Institute of Pacific Islands Forestry Pacific Southwest Research StationUSDA Forest ServiceHiloHI 96720USA

Coastal regions are highly susceptible to the effects of global warming,including rising atmospheric and sea surface temperatures,increased cyclone frequency,and sea level ***,it is imperative to examine coastal vulnerability to minimize the impact of multiple hazards and protect coastal resources,such as *** in India studying the vulnerability of coastal zones of Andaman and Nicobar Islands which fall in seismic zone V is critical for conservation *** conducted a vulnerability analysis of coastal zones impacted by the 2004 earthquake,causing varying degrees of ground upliftment and *** compared coastal vulnerability among sites that experienced uplift,no change,and subsidence(the southern portion).Our analysis utilized the Coastal and Mangrove Vulnerability Index(CVI and MVI)to measure and compare vulnerability in six zones distributed along uplift and subsidence ***-resolution satellite imagery including WorldView-2,3,and GeoEye-1 from year 2022 are utilized on this *** CVI and MVI offers a good way to measure and compare vulnerabilities across sites and offer insights for better *** CVI and MVI results indicate that approximately 34%of coastal grids and over 23%of mangrove grids across all zones are highly to extremely highly *** zones were found to be more vulnerable than uplifted *** findings suggest that large-scale natural disturbances such as tectonic displacement have the potential to impact coastal vegetation and mangrove cover can become even more *** conclusion,our study emphasizes the importance of vulnerability analyses in coastal regions,especially in areas prone to seismic *** findings have direct implications for conservation and restoration efforts and underscore the need for continued monitoring and mitigation efforts to safeguard coastal resources for long-term sustainability.

关键词： Mangroves Coastal vulnerability Mangrove vulnerability 2004 Indian Ocean earthquake Andaman Island

Effectiveness of hybrid ensemble machine learning models for landslide susceptibility analysis:Evidence from Shimla district of North-west Indian Himalayan region

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Journal of Mountain Science 2024年第7期21卷 2368-2393页

作者： SHARMA Aastha SAJJAD Haroon RAHAMAN Md Hibjur saha Tamal Kanti BHUYAN Nirsobha Department of Geography Faculty of SciencesJamia Millia IslamiaNew Delhi-110025India

The Indian Himalayan region is frequently experiencing climate change-induced ***,landslide susceptibility assessment assumes greater significance for lessening the impact of a landslide *** paper makes an attempt to assess landslide susceptibility in Shimla district of the northwest Indian Himalayan *** examined the effectiveness of random forest(RF),multilayer perceptron(MLP),sequential minimal optimization regression(SMOreg)and bagging ensemble(B-RF,BSMOreg,B-MLP)models.A landslide inventory map comprising 1052 locations of past landslide occurrences was classified into training(70%)and testing(30%)*** site-specific influencing factors were selected by employing a multicollinearity *** relationship between past landslide occurrences and influencing factors was established using the frequency ratio *** effectiveness of machine learning models was verified through performance *** landslide susceptibility maps were validated by the area under the receiver operating characteristic curves(ROC-AUC),accuracy,precision,recall and *** key performance metrics and map validation demonstrated that the BRF model(correlation coefficient:0.988,mean absolute error:0.010,root mean square error:0.058,relative absolute error:2.964,ROC-AUC:0.947,accuracy:0.778,precision:0.819,recall:0.917 and F-1 score:0.865)outperformed the single classifiers and other bagging ensemble models for landslide *** results show that the largest area was found under the very high susceptibility zone(33.87%),followed by the low(27.30%),high(20.68%)and moderate(18.16%)susceptibility *** factors,namely average annual rainfall,slope,lithology,soil texture and earthquake magnitude have been identified as the influencing factors for very high landslide *** texture,lineament density and elevation have been attributed to high and moderate ***,the study calls for devising suitable landslide mitig

关键词： Landslide susceptibility Site-specific factors Machine learning models Hybrid ensemble learning Geospatial techniques Himalayan region

New insights into spexin and pituitary adenylate cyclase-activating polypeptide(PACAP)in regulating fish reproduction

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Aquaculture and Fisheries 2024年第3期9卷 411-416页

作者： Ashis saha Mrinal Samanta Hirak kumar Barman Shiba Shankar Giri Division of Fish Nutrition and Physiology ICAR-Central Institute of Freshwater AquacultureKausalyagangaBhubaneswarOdisha751002India Division of Fish Health Management ICAR-Central Institute of Freshwater AquacultureKausalyagangaBhubaneswarOdisha751002India Division of Fish Genetics and Biotechnology ICAR-Central Institute of Freshwater AquacultureKausalyagangaBhubaneswarOdisha751002India

Reproduction is one of the most crucial physiological processes for the continuation of the generation of any *** are one of the most divergent aquatic *** reproductive neuro-endocrine regulatory studies are limited to only few *** regulation is a finely tuned complex mechanistic pathways,involving mainly hypothalamic-pituitary-gonad(HPG)*** the HPG axis,gonadotropin-releasing hormone(GnRH)modulates the synthesis and release of pituitary gonadotropins,which act on the gonads to stimulate steroidogenesis and *** recently,several novel neuropeptides,associated with reproductive regulation,have been ***(SPX),a novel neuropeptide coevolved with the galanin/kisspeptin family,has been identified as a regulator of the species-specific reproductive processes in *** adenylate cyclase-activating polypeptide(PACAP)is another novel member of the secretin-glucagon peptide family that functions as a hypophysiotropic factor involved in regulating pituitary hormone secretion in *** two emerging neuropeptides have pleiotropic functions,but information regarding their exact roles in fish reproduction is very *** updated overview of the mechanistic reproductive functions of these two new neuropeptides are highlighted in this review.

关键词： insight continuation exact

Hydro-uvarovite from Mantle Peridotites of Naga Hills Ophiolite: A Mineral Tracer for Neo-Tethyan Mantle Wedge Metasomatism

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Acta Geologica Sinica(English Edition) 2024年第4期98卷 867-877页

作者： Anisha VERENCAR Abhishek saha Nilanjana SORCAR Sohini GANGULY Pankaj KUMAR Atul Kumar SINGH CSIR-National Institute of Oceanography Dona PaulaGoa 403004India School of Earth Ocean and Atmospheric SciencesGoa UniversityTaleigao PlateauGoa 403206India National Centre for Earth Science Studies ThiruvananthapuramKeralaIndia Inter University Accelerator Centre(IUAC) New Delhi 110067India North-Eastern Hill University ShillongMeghalaya 793022India

Hydrous Cr-bearing uvarovite garnets are rare in natural occurrences and belong to the ugrandite series and exist in binary solid solutions with grossular and andradite garnets. Here, we report the occurrence of hydrous uvarovite garnet having Cr_(2)O_(3) upto 19.66 wt% and CaO of 32.12–35.14 wt% in the serpentinized mantle peridotites of Naga Hills Ophiolite(NHO), India. They occur in association with low-Cr diopsides. They are enriched in LILE(Ba, sr), LREEs, with fractionating LREE-MREE [avg.(La/Sm)_(N) = 2.16] with flat MREE/HREE patterns [avg.(Sm/Yb)_(N) = 0.95]. Raman spectra indicate the presence of hydroxyl(OH^(–)) peaks from 3500 to 3700 cm^(-1). Relative abundances in fluid mobile elements and their close association with clinopyroxenes are suggestive of the formation of uvarovite garnets through low temperature metasomatic alteration of low-Cr diopsides by hydrothermal slab fluids. The high LREE concentration and absence of Eu anomaly in the garnet further attest to alkaline nature of the transporting slab dehydrated fluid rather the involvement of low-p H solution. The chemical characteristics of the hydroxyl bearing uvarovite hosted by the mantle peridotite of NHO deviate from the classical features of uvarovite garnet, and their origin is attributed to the fluid-induced metasomatism of the sub arc mantle wedge in a suprasubduction zone regime.

关键词： uvarovite hydroxyl metasomatic alteration low-Cr diopsides serpentinization mantle peridotite

Improving Heat Transfer in Parabolic Trough Solar Collectors by Magnetic Nanofluids

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Energy Engineering 2024年第4期121卷 835-848页

作者： Ritesh Singh Abhishek Gupta Akshoy Ranjan Paul Bireswar Paul Suvash C.saha Department of Applied Mechanics Motilal Nehru National Institute of Technology AllahabadPrayagrajIndia Department of Mechanical and Mechatronic Engineering University of Technology SydneySydneyAustralia

A parabolic trough solar collector(PTSC)converts solar radiation into thermal ***,low thermal efficiency of PTSC poses a hindrance to the deployment of solar thermal power *** performance of PTSC is enhanced in this study by incorporating magnetic nanoparticles into the working *** circular receiver pipe,with dimensions of 66 mm diameter,2 mm thickness,and 24 m length,is exposed to uniform temperature and velocity *** working fluid,Therminol-66,is supplemented with Fe3O4 magnetic nanoparticles at concentrations ranging from 1%to 4%.The findings demonstrate that the inclusion of nanoparticles increases the convective heat transfer coefficient(HTC)of the PTSC,with higher nanoparticle volume fractions leading to greater heat transfer but increased pressure *** thermal enhancement factor(TEF)of the PTSC is positively affected by the volume fraction of nanoparticles,both with and without a magnetic ***,the scenario with a 4%nanoparticle volume fraction and a magnetic field strength of 250 G exhibits the highest TEF,indicating superior thermal *** findings offer potential avenues for improving the efficiency of PTSCs in solar thermal plants by introducing magnetic nanoparticles into the working fluid.

关键词： Parabolic trough solar collector(PTSC) magnetic nanofluid(MNF) heat transfer convective heat transfer coefficient(HTC) thermal enhancement factor(TEF)