检索结果-南通市图书馆

General Solutions of First-Order Algebraic ODEs in Simple Constant Extensions

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2023年第4期36卷 1769-1788页

作者： MITTERAMSKOGLER Johann Josef winkler franz Research Institute for Symbolic Computation(RISC) Johannes Kepler Universität LinzA-4040 LinzAustria

If a first-order algebraic ODE is defined over a certain differential field,then the most elementary solution class,in which one can hope to find a general solution,is given by the adjunction of a single arbitrary constant to this *** of this type give rise to a particular kind of generic point—a rational parametrization—of an algebraic curve which is associated in a natural way to the ODE’s defining *** for the opposite direction,we show that a suitable rational parametrization of the associated curve can be extended to a general solution of the ODE if and only if one can find a certain automorphism of the solution *** automorphisms are determined by linear rational functions,i.e.,Möbius *** properties of rational parametrizations,in combination with the particular shape of such automorphisms,lead to a number of necessary conditions on the existence of general solutions in this solution ***,the desired linear rational function can be determined by solving a comparatively simple differential system over the ODE’s field of *** results hold for arbitrary differential fields of characteristic zero.

关键词： Algebraic curve algebraic differential equation general solution Möbius transformation rational parametrization

RATIONAL GENERAL SOLUTIONS OF HIGHER ORDER ALGEBRAIC ODES

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2013年第2期26卷 261-280页

作者： HUANG Yanli NG L X Chu winkler franz School of Computer Science and Software Engineering Tianjin Polytechnic University Research Institute for Symbolic Computation(RISC) Johannes Kepler University Department of Mathematics Quy Nhon University

This paper generalizes the method of Ng6 and winkler （2010, 2011） for finding rational general solutions of a first order non-autonomous algebraic ordinary differential equation （AODE） to the case of a higher order AODE, provided a proper parametrization of its solution hypersurface. The authors reduce the problem of finding the rational general solution of a higher order AODE to finding the rational general solution of an associated system. The rational general solutions of the original AODE and its associated system are in computable 1-1 correspondence. The authors give necessary and sufficient conditions for the associated system to have a rational solution based on proper reparametrization of invariant algebraic space curves. The authors also relate invariant space curves to first integrals and characterize rationally solvable systems by rational first integrals.

关键词： Algebraic ODE associated system invariant algebraic space curve rational first integral rational general solution.

Grbner bases in difference-differential modules and difference-differential dimension polynomials

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2008年第9期51卷 1732-1752页

作者： franz winkler RISC-Linz J. Kepler University Linz A-4040 Linz Austria

In this paper we extend the theory of Grbner bases to difference-differential modules and present a new algorithmic approach for computing the Hilbert function of a finitely generated difference-differential module equipped with the natural filtration. We present and verify algorithms for construct-ing these Grbner bases counterparts. To this aim we introduce the concept of "generalized term order" on Nm ×Zn and on difference-differential modules. Using Grbner bases on difference-differential mod-ules we present a direct and algorithmic approach to computing the difference-differential dimension polynomials of a difference-differential module and of a system of linear partial difference-differential equations.

关键词： Grbner basis generalized term order difference-differential module difference-differential dimension polynomial

Traction-assisted endoscopic mucosal resection for polypectomy in the large intestine

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2010年第43期16卷 5462-5466页

作者： Bernhard Dauser Thomas winkler Behrooz Salehi Stefan Riss franz Beer Friedrich Herbst Department of Surgery St. John of God Hospital Department of Surgery Medical University of Vienna Kerjaschki Laboratory of Pathology

AIM: To evaluate if traction-assisted endoscopic mucosal resection (TA-EMR) is feasible and if it enables en bloc resection of colorectal lesions. METHODS: Seven patients with a total of 12 colorectal adenomas were prospectively enrolled. All lesions were removed by TA-EMR: one hemostatic clip tied to a white silk suture was applied to the base of the lesion to allow traction through the working channel of the colonoscope. A conventional polypectomy snare was mounted over the suture and the lesion was pulled into the snare and resected in one piece. RESULTS: All 12 lesions (nine sessile) were resected en bloc with free lateral and vertical margins by using this novel technique, including five lesions (5/12, 41.6%) in less-accessible positions, where TA-EMR enabled complete visualization of the base before resection. Mean longest lesion and specimen sizes were 9 mm (range: 6-25 mm) and 11 mm in diameter (range: 7-17 mm),respectively. No serious procedure-related complications were observed. CONCLUSION: TA-EMR through the endoscope using a hemostatic clip and suture material is technically feasible. Visualization of colorectal lesions in less-accessible locations can be improved.

关键词： Traction-assisted Endoscopic mucosal resection Colon polyp Colonoscopy

Immediate regularization of measure-type population densities in a two-dimensional chemotaxis systemwith signal consumption

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Mathematics 2021年第4期64卷 725-746页

作者： Yulan Wang Michael winkler Zhaoyin Xiang School of Science Xihua UniversityChengdu 610039China Institut für Mathematik Universität PaderbornPaderbom 33098Germany School of Mathematical Sciences University of Electronic Science and Technology of ChinaChengdu 611731China

This paper deals with the Neumann initial-boundary value problem for a classical chemotaxis system with signal consumption in a *** contrast to previous studies which have established a comprehensive theory of global classical solutions for suitably regular nonnegative initial data,the focus in the present work is on the question to which extent initially prescribed singularities can be regularized despite the presence of the nonlinear cross-diffusive *** main result in this paper asserts that at least in the framework of radial solutions immediate regularization occurs under an essentially optimal condition on the initial distribution of the population *** precisely,it will turn out that for any radially symmetric initial data belonging to the space of regular signed Borel measures for the population density and to L^(2) for the signal density,there exists a classical solution to the Neumann initial-boundary value problem,which is smooth and approaches the given initial data in an appropriate trace sense.

关键词： chemotaxis measure valued initial data instantaneous smoothing global existence

A Smallness Condition Ensuring Boundedness in a Two-dimensional Chemotaxis-Navier-Stokes System involving Dirichlet Boundary Conditions for the Signal

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2022年第6期38卷 985-1001页

作者： Yu Lan WANG Michael winkler Zhao Yin XIANG School of Science Xihua UniversityChengdu 610039P.R.China Institut fur Mathematik Universitat Paderborn33098 PaderbornGermany School of Mathematical Sciences University of Electronic Science and Technology of ChinaChengdu 611731P.R.China

The chemotaxis-Navier-Stokes system{nt+u・∇n=Δn−∇・(n∇c),ct+u・∇c=Δc−nc,ut+(u・∇)u=Δu+∇P+n∇φ,∇・u=0is considered in a smoothly bounded planar domainΩunder the boundary conditions(∇n−n∇c)・ν=0,c=c,u=0,x∈∂Ω,t>0,with a given nonnegative constant c_(*).It is shown that if(n_(0),c_(0),u_(0))is sufficiently regular and such that the product||n_(0)||L^(1)(Ω)||c_(0)||^(2)L^(∞)(Ω)is suitably small,an associated initial value problem possesses a bounded classical solution with(n,c,u)|_(t=0)=(n_(0),c_(0),u_(0)).

关键词： Chemotaxis Navier-Stokes system Dirichlet boundary condition

Topology of triple-point metals

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2019年第7期28卷 54-72页

作者： Georg W.winkler Sobhit Singh Alexey A.Soluyanov Microsoft Quantum Microsoft Station Q University of California Santa Barbara California 93106-6105 USA Department of Physics and Astronomy Rutgers University Piscutuwny New Jersey 08854 USA Institute of Physics University of Zurich. Winterthurerstrasse 190 8057 Zurich Switzerland Department of Physics. St. Petersburg State University St. Petersburg 199034Russia

We discuss and illustrate the appearance of topological fermions and bosons in triple-point metals where a band crossing of three electronic bands occurs close to the Fermi *** bosons appear in the phonon spectrum of certain triple-point metals, depending on the mass of atoms that form the binary triple-point *** first provide a classification of possible triple-point electronic topological phases possible in crystalline compounds and discuss the consequences of these topological phases, seen in Fermi arcs, topological Lifshitz transitions, and transport *** we show how the topological phase of phonon modes can be extracted and proven for relevant ***,we show how the interplay of electronic and phononic topologies in triple-point metals puts these metallic materials into the list of the most efficient metallic thermoelectrics known to date.

关键词： topological metals topological phonons electronic structure thermoelectrics

B-cell and antibody responses to SARS-CoV-2:infection,vaccination,and hybrid immunity

在线全文

学校读者我要写书评

暂无评论

Cellular & Molecular Immunology 2024年第2期21卷 144-158页

作者： Dennis Lapuente Thomas H.winkler Matthias Tenbusch Institut für klinische und molekulare Virologie Universitätsklinikum Erlangen und Friedrich-Alexander-Universität(FAU)Erlangen-NürnbergSchlossgarten 491054 ErlangenGermany Department of Biology Division of GeneticsNikolaus-Fiebiger-Center for Molecular MedicineFriedrich-Alexander-Universität Erlangen-Nürnberg(FAU)ErlangenGermany Medical Immunology Campus Erlangen Friedrich-Alexander-Universität(FAU)Erlangen-NürnbergSchlossplatz 191054 ErlangenGermany

The emergence of severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)in 2019 prompted scientific,medical,and biotech communities to investigate infection-and vaccine-induced immune responses in the context of this pathogen.B-cell and antibody responses are at the center of these investigations,as neutralizing antibodies(nAbs)are an important correlate of protection(COP)from infection and the primary target of SARS-CoV-2 vaccine *** addition to absolute levels,nAb longevity,neutralization breadth,immunoglobulin isotype and subtype composition,and presence at mucosal sites have become important topics for scientists and health policy *** recent pandemic was and still is a unique setting in which to study de novo and memory B-cell(MBC)and antibody responses in the dynamic interplay of infection-and vaccine-induced *** also provided an opportunity to explore new vaccine platforms,such as mRNA or adenoviral vector vaccines,in unprecedented cohort *** with the technological advances of recent years,this situation has provided detailed mechanistic insights into the development of B-cell and antibody responses but also revealed some unexpected *** this review,we summarize the key findings of the last 2.5 years regarding infection-and vaccine-induced B-cell immunity,which we believe are of significant value not only in the context of SARS-CoV-2 but also for future vaccination approaches in endemic and pandemic settings.

关键词： SARS-CoV-2 neutralizing antibodies memory responses vaccines IgG4

Collembola communities and soil conditions in forest plantations established in an intensively managed agricultural area

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Forestry Research 2021年第5期32卷 1819-1832页

作者： István Harta Barbara Simon Szergej Vinogradov Dániel winkler Institute of Environmental Science Szent István UniversityGödöllőHungary Institute of Methodology Szent István UniversityGödöllőHungary Institute of Wildlife Management and Vertebrate Zoology University of SopronSopronHungary

The challenges of a changing climate have directed greater attention to afforestation,but the effects of afforestation on soil fertility and soil biota have not been fully *** explore changes in the soil conditions in two 20-year-old forest plantations established in formerly intensively fertilized plots of agricultural land,we focused on the current developmental state of the sites that received the most fertilizer and evaluated soil properties and Collembola(springtails)*** oak(Quercus petraea)and black locust(Robinia pseudoacacia)that had been planted in the afforestation sites were assessed for differences between plantations of native and invasive *** adjacent reference associations,including forests and open habitats,were also analyzed and *** showed that the soils in the two afforested sites were similar in their properties and Collembola communities to those of the control cultivated forests,but differed from each other in pH,calcium,phosphorus,and ammonium *** available potassium and phosphorus contents in the soil of the sessile oak plantation were still high,while the soil organic matter content was adequate(SOM>2.0%)in both *** richness of Collembola ranged from 18 in the cultivated arable land to 43 in the relict *** a few species typical for forests(e.g.,Neanura muscorum,Isotomiella minor,Entomobrya muscorum)were detected in the young plantations,while species characteristic of open habitats(e.g.,Protaphorura campata,Lepidocyrtus cyaneus)occurred as *** more individuals and species of Collembola were present in the soil of young plantations than in arable fields,their community diversities were significantly lower compared to the control forest *** community diversity differed significantly also between the two plantation types(with native and non-native tree species).Mean abundance in the afforested sites was about 2.5 times higher than in the cultiv

关键词： Afforestation Diversity Fertilizers Soil fauna Soil properties Springtails