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Search for H I emission from superdisk candidates associated with radio galaxies

Research in Astronomy and Astrophysics 2019年第6期19卷 71-78页

作者： Abhijeet Anand Nirupam Roy gopal-krishna Max-Planck-Institut fur Astrophysik Karl-Schwarzschild-Str. 1 D-85741 Garching Germany Department of Physics Indian Institute of Science Bangalore - 560012 India Aryabhatta Research Institute of Observational Sciences (ARIES) Manora Peak Nainital - 263129 India Max-Planck-Institut fur Radioastronomie Auf dem Hugel 69 53121 Bonn Germany

Giant gaseous layers(termed “superdisks”) have been hypothesized in the past to account for the strip-like radio emission gap(or straight-edged central brightness depression) observed between twin radio lobes, in over a dozen relatively nearby powerful Fanaroff-Riley Class II radio galaxies. They could also provide a plausible alternative explanation for a range of observations. Although a number of explanations have been proposed for the origin of the superdisks, little is known about their material content. Some X-ray observations of superdisk candidates indicate the presence of hot gas, but a cool dusty medium also seems to be common. If they are entirely or partly composed of neutral gas, then it may be directly detectable and we report here a first attempt to detect/image any neutral hydrogen gas present in the superdisks that are inferred to be present in four nearby radio galaxies. We have not found a positive H I signal in any of the four sources, resulting in tight upper limits on the H I number density in the postulated superdisks,estimated directly from the central rms noise values of the final radio continuum subtracted image. The estimated ranges of the upper limit on neutral hydrogen number density and column density are 10^-4-10^-3 atoms per cm3 and 10^19-10^20 atoms per cm^2, respectively. No positive H I signal is detected even after combining all the four available H I images(with inverse variance weighting). This clearly rules out an H I dominated superdisk as a viable model to explain these structures, however, the possibility of a superdisk being composed of warm/hot gas still remains open.

关键词： galaxies:active galaxies:general galaxies:structure radio lines:galaxies

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Illumination-Free Clustering Using Improved Slime Mould Algorithm for Acute Lymphoblastic Leukemia Image Segmentation

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Journal of Bionic Engineering 2023年第6期20卷 2916-2934页

作者： krishna gopal Dhal Swarnajit Ray Sudip Barik Arunita Das Department of Computer Science and Application Midnapore College(Autonomous)Paschim MedinipurMidnaporeWest BengalIndia Department of Computer Science and Engineering Maulana Abul Kalam Azad University of TechnologyKolkataWest BengalIndia Department of Computer Science and Engineering Kalyani Government Engineering CollegeKalyaniWest BengalIndia

Partitional clustering techniques such as K-Means(KM),Fuzzy C-Means(FCM),and Rough K-Means(RKM)are very simple and effective techniques for image ***,because their initial cluster centers are randomly determined,it is often seen that certain clusters converge to local *** addition to that,pathology image segmentation is also problematic due to uneven lighting,stain,and camera settings during the microscopic image capturing ***,this study proposes an Improved Slime Mould Algorithm(ISMA)based on opposition based learning and differential evolution’s mutation strategy to perform illumination-free White Blood Cell(WBC)*** ISMA helps to overcome the local optima trapping problem of the partitional clustering techniques to some *** paper also performs a depth analysis by considering only color components of many well-known color spaces for clustering to find the effect of illumination over color pathology image *** and visual results encourage the utilization of illumination-free or color component-based clustering approaches for image ***-KM and“ab”color channels of CIELab color space provide best results with above-99%accuracy for only nucleus ***,for entire WBC segmentation,ISMA-KM and the“CbCr”color component of YCbCr color space provide the best results with an accuracy of above 99%.Furthermore,ISMA-KM and ISMA-RKM have the lowest and highest execution times,*** the other hand,ISMA provides competitive outcomes over CEC2019 benchmark test functions compared to recent well-established and efficient Nature-Inspired Optimization Algorithms(NIOAs).

关键词： Pathology image Image segmentation Clustering Color space White blood cell Optimization Swarm intelligence Fuzzy clustering Rough clustering

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On the origin of X-shaped radio galaxies

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Research in Astronomy and Astrophysics 2012年第2期12卷 127-146页

作者： gopal-krishna Peter L.Biermann Lszló .Gergely Paul J.Wiita National Centre for Radio Astrophysics TIFRPune University Campus Max Planck Institute for Radioastronomy Department of Physics & Astronomy University of Bonn Department of Physics & Astronomy University of Alabama Department of Physics University of Alabama at Huntsville KIT-Karlsruhe Institute for Technology Institute for Experimental Nuclear Physics Department of Theoretical Physics University of Szeged Department of Experimental Physics University of Szeged Department of Physics The College of New Jersey

After a brief, critical review of the leading explanations proposed for the small but important subset of radio galaxies showing an X-shaped morphology （XRGs） we propose a generalized model, based on the jet-shell interaction and spin- flip hypotheses. The most popular scenarios for this intriguing phenomenon invoke either hydrodynamical backflows and over-pressured cocoons or rapid jet reorienta- tions, presumably from the spin-flips of central engines following the mergers of pairs of galaxies, each of which contains a supermassive black hole. We confront these models with a number of key observations, and thus argue that none of the models is capable of explaining the entire range of the salient observational properties of XRGs, although some of the arguments raised in the literature against the spin-flip scenario are probably not tenable. We then propose a new scenario which also involves galac- tic mergers but would allow the spin of the central engine to maintain its direction. Motivated by detailed multi-band observations of the nearest radio galaxy, Centaurus A, this new model emphasizes the role of the interactions between the jets and the shells of stars and gas that form and rotate around the merged galaxy and can cause temporary deflections of the jets, occasionally giving rise to an X-shaped radio struc- ture. Although each model is likely to be relevant to a subset of XRGs, the bulk of the evidence indicates that most of them are best explained by the jet-shell interaction or spin-flip hypotheses.

关键词： galaxies: active - galaxies: jets - gravitational waves - ISM - radiocontinuum: galaxies

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Gilbert's syndrome: High frequency of the (TA)_7 TAA allele in India and its interaction with a novel CAT insertion in promoter of the gene for bilirubin UDP-glucuronosyltransferase 1 gene

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World Journal of Gastroenterology 2006年第14期12卷 2269-2275页

作者： Shabana Farheen Sanghamitra Sengupta Amal Santra Suparna Pal gopal krishna Dhali Meenakshi Chakravorty Partha P Majumder Abhijit Chowdhury Human Genetics Unit Indian Statistical Institute KolkataIndia Department of Gastroenterology Institute of Postgraduate Medical Education & Research KolkataIndia Human Genetics & Genomics Division Indian Institute of Chemical Biology KolkataIndia

AIM： To identify the variants in U rase 1 （UGT1A1） gene in Gilbert＇s syndrome （GS） and to estimate the association between homozygosity for TA insertion and GS in India, as well as the frequency of TA insertion and its impact among normal controls in India. METHODS： Ninety-five GS cases and 95 normal controls were selected. Liver function and other tests were done. The promoter and all 5 exons of UGT1A1 gene were resequenced. Functional assessment of a novel trinucleotide insertion was done by in silico analysis and by estimating UGT1A1 promoter activity carried out by ludferase reporter assay of appropriate constructs in Hep G2 cell line. RESULTS： Among the GS patients, 80% were homozygous for the TA insertion, which was several-fold higher than reports from other ethnic groups. The mean UCB level was elevated among individuals with only one copy of this insertion, which was not significantly different from those with two copies. Many new DNA variants in UGT1A1 gene were discovered, including a trinucleotide （CAT） insertion in the promoter found in a subset （10%） of GS patients, but not among normal controls. In-silico analysis showed marked changes in the DNA-folding of the promoter and functional analysis showed a 20-fold reduction in transcription efficiency of UGT1A1 gene resulting from this insertion, thereby significantly elevating the UCB level. CONCLUSION： The genetic epidemiology of GS is variable across ethnic interactions among UGT1A1 groups and the epistatic promoter variants modulate bilirubin glucuronidation.

关键词： Unconjugated hyperbilirubinemia UGT1A1 gene DNA resequencing Luciferase reporter assay

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Evaluation of mandibular reconstruction with free vascularized fibular flap

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Journal of Nanjing Medical University 2008年第1期22卷 23-27页

作者： krishna gopal Bhuju Department of Oral & Maxillofacial Surgery the Affiliated Stomatological Hospital of Nanjing Medical UniversityNanjing 210029Jiangsu ProvinceChina

Objective： To evaluates mandible reconstruction by free vascularized fibular flap with special emphasis on the immediate complications. Methods：The clinical data of 63 patients were reviewed, 35 male and 28 female（age range 16 to 73 years）. Aesthetic and functional outcomes were evaluated by follow-up and/or telephone conversation. Results：Among the 63 fibular flaps, 29 were osteocutaneous flaps with one or two skin islands. All the flaps were surviving well and the success rate was 100%. Long term donor site disability was not recorded for any patient. Thirty-one patients responded for aesthetic and functional evaluation, 20 cases（64.5%） reported their facial appearance as excellent or good, 11 （35.48%） felt fair; 14 cases （45%） could eat unrestricted diet, 17（55%） could eat soft diet; 21 cases were（67.67%） speech normal, 10（22.33%） speech intelligible. Conclusion：Free fibular flap reflects good functional and esthetic results with a high degree of consistency, and acceptable level of complications, and we strongly believe the vascularized fibular flap is the first choice for mandibular reconstruction.

关键词： mandibular reconstruction free fibular flap osteocutaneous flap functional aesthetic evaluation

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Development of Application Specific Continuous Speech Recognition System in Hindi

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Journal of Signal and Information Processing 2012年第3期3卷 394-401页

作者： Gaurav Gaurav Devanesamoni Shakina Deiv gopal krishna Sharma Mahua Bhattacharya Indian Institute of Information Technology & Management

Application specific voice interfaces in local languages will go a long way in reaching the benefits of technology to rural India. A continuous speech recognition system in Hindi tailored to aid teaching Geometry in Primary schools is the goal of the work. This paper presents the preliminary work done towards that end. We have used the Mel Frequency Cepstral Coefficients as speech feature parameters and Hidden Markov Modeling to model the acoustic features. Hidden Markov Modeling Tool Kit —3.4 was used both for feature extraction and model generation. The Julius recognizer which is language independent was used for decoding. A speaker independent system is implemented and results are presented.

关键词： Automatic Speech Recognition Mel Frequency Cepstral Coefficients Hidden Markov Modeling

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Operator Equations Inducing Some Generalizations of Slant Hankel Operators

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Acta Mathematica Sinica,English Series 2024年第8期40卷 2017-2036页

作者： gopal DATT Bhawna Bansal GUPTA Department of Mathematics PGDAV CollegeUniversity of DelhiNew Delhi-110065India Department of Mathematics Miranda HouseUniversity of DelhiDelhi-110007India

An extension of slant Hankel operator,namely,the kth-orderλ-slant Hankel operator on the Lebesgue space L^(2)(T^(n)),where T is the unit circle and n≥1,a natural number,is described in terms of the solution of a system of operator equations,which is subsequently expressed in terms of the product of a slant Hankel operator and a unitary *** study is further lifted in Calkin algebra in terms of essentially kth-orderλ-slant Hankel operators on L^(2)(T^(n)).

关键词： Hankel operator Lebesgue space of n-dimensional torus kth-order slant Hankel operator essentially kth-orderλ-slant Hankel operator

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An inverse analysis of fluid flow through granular media using differentiable lattice Boltzmann method

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2077-2090页

作者： Qiuyu Wang krishna Kumar Department of Civil Architectural and Environmental EngineeringUniversity of Texas at AustinAustin78712-2100USA

This study presents a method for the inverse analysis of fluid flow *** focus is put on accurately determining boundary conditions and characterizing the physical properties of granular media,such as permeability,and fluid components,like *** primary aim is to deduce either constant pressure head or pressure profiles,given the known velocity field at a steady-state flow through a conduit containing obstacles,including walls,spheres,and *** lattice Boltzmann method(LBM)combined with automatic differentiation(AD)(AD-LBM)is employed,with the help of the GPU-capable Taichi programming language.A lightweight tape is used to generate gradients for the entire LBM simulation,enabling end-to-end *** AD-LBM approach accurately estimates the boundary conditions for complex flow paths in porous media,leading to observed steady-state velocity fields and deriving macro-scale permeability and fluid *** method demonstrates significant advantages in terms of prediction accuracy and computational efficiency,making it a powerful tool for solving inverse fluid flow problems in various applications.

关键词： Inverse problem Fluid flow Granular media Automatic differentiation(AD) Lattice Boltzmann method(LBM)

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Constructing a biofunctionalized 3D-printed gelatin/sodium alginate/chitosan tri-polymer complex scaffold with improvised biological andmechanical properties for bone-tissue engineering

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Bio-Design and Manufacturing 2024年第1期7卷 57-73页

作者： Amit Kumar Singh krishna Pramanik Amit Biswas Centre of Excellence in Tissue Engineering Department of Biotechnology and Medical EngineeringNational Institute of TechnologyRourkela 769008India

Sodium alginate(SA)/chitosan(CH)polyelectrolyte scaffold is a suitable substrate for tissue-engineering *** present study deals with further improvement in the tensile strength and biological properties of this type of scaffold to make it a potential template for bone-tissue *** experimented with adding 0%–15%(volume fraction)gelatin(GE),a protein-based biopolymer known to promote cell adhesion,proliferation,and *** resulting tri-polymer complex was used as bioink to fabricate SA/CH/GEmatrices by three-dimensional(3D)*** studies using scanning electron microscopy revealed the microfibrous porous architecture of all the structures,which had a pore size range of 383–419μm.X-ray diffraction and Fourier-transform infrared spectroscopy analyses revealed the amorphous nature of the scaffold and the strong electrostatic interactions among the functional groups of the polymers,thereby forming polyelectrolyte complexes which were found to improve mechanical properties and structural *** scaffolds exhibited a desirable degradation rate,controlled swelling,and hydrophilic characteristics which are favorable for bone-tissue *** tensile strength improved from(386±15)to(693±15)kPa due to the increased stiffness of SA/CH scaffolds upon addition of *** enhanced protein adsorption and in vitro bioactivity(forming an apatite layer)confirmed the ability of the SA/CH/GE scaffold to offer higher cellular adhesion and a bone-like environment to cells during the process of tissue *** vitro biological evaluation including the MTT assay,confocal microscopy analysis,and alizarin red S assay showed a significant increase in cell attachment,cell viability,and cell proliferation,which further improved biomineralization over the scaffold *** addition,SA/CH containing 15%gelatin designated as SA/CH/GE15 showed superior performance to the other fabricated 3D structures,demonstrating its pote

关键词： Scaffold Biomaterial Sodium alginate Chitosan Gelatin 3D printing Tissue engineering

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Improved Energy Management Strategy for Prosumer Buildings with Renewable Energy Sources and Battery Energy Storage Systems

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Journal of Modern Power Systems and Clean Energy 2024年第2期12卷 381-392页

作者： Pavitra Sharma krishna Kumar Saini Hitesh Datt Mathur Puneet Mishra Department of Electrical&Electronics Engineering Birla Institute of Technology&SciencePilaniIndia IEEE

The concept of utilizing microgrids(MGs)to convert buildings into prosumers is gaining massive popularity because of its economic and environmental *** pro-sumer buildings consist of renewable energy sources and usually install battery energy storage systems(BESSs)to deal with the uncertain nature of renewable energy ***,because of the high capital investment of BESS and the limitation of available energy,there is a need for an effective energy management strategy for prosumer buildings that maximizes the profit of building owner and increases the operating life span of *** this regard,this paper proposes an improved energy management strategy(IEMS)for the prosumer building to minimize the operating cost of MG and degradation factor of ***,to estimate the practical operating life span of BESS,this paper utilizes a non-linear battery degradation *** addition,a flexible load shifting(FLS)scheme is also developed and integrated into the proposed strategy to further improve its *** proposed strategy is tested for the real-time annual data of a grid-tied solar photovoltaic(PV)and BESS-powered AC-DC hybrid MG installed at a commercial ***,the scenario reduction technique is used to handle the uncertainty associated with generation and load *** validate the performance of the proposed strategy,the results of IEMS are compared with the well-established energy management *** simulation results verify that the proposed strategy substantially increases the profit of the building owner and operating life span of ***,FLS enhances the performance of IEMS by further improving the financial profit of MG owner and the life span of BESS,thus making the operation of prosumer building more economical and efficient.

关键词： Prosumer building battery energy storage system(BESS) battery degradation factor demand response energy management microgrid solar photovoltaic(PV)system

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