77 research outputs found
Existence and multiplicity of Homoclinic solutions for the second order Hamiltonian systems
In this paper we study the existence and multiplicity of homoclinic solutions
for the second order Hamiltonian system ,
, by means of the minmax arguments in the critical
point theory, where is unnecessary uniformly positively definite for all
and sastisfies the asymptotically linear
condition.Comment: published in International Mathematical Forum, Vol. 6, 2011, no. 4,
159 - 17
Homoclinic orbits for a class of nonperiodic Hamiltonian systems with some twisted conditions
In this paper, by the Masolv index theory, we will study the existence and
multiplicity of homoclinic orbits for a class of asymptotically linear
nonperiodic Hamiltonian systems with some twisted conditions on the Hamiltonian
function
Infinitely many periodic solutions for second order Hamiltonian systems
In this paper, we study the existence of infinitely many periodic solutions
for second order Hamiltonian systems , where is either asymptotically quadratic or superquadratic as .Comment: to appear in JDE(doi:10.1016/j.jde.2011.05.021
Infinitely many solutions for SchrĂśdingerâKirchhoff-type equations involving indefinite potential
In this paper, we study the multiplicity of solutions for the following SchrĂśdingerâKirchhoff-type equation
where , are constants and the potential may be unbounded from below. Under some mild conditions on the nonlinearities and , we obtain the existence of infinitely many solutions for this problem. Recent results from the literature are generalized and significantly improved
PM2.5-GNN: A Domain Knowledge Enhanced Graph Neural Network For PM2.5 Forecasting
When predicting PM2.5 concentrations, it is necessary to consider complex
information sources since the concentrations are influenced by various factors
within a long period. In this paper, we identify a set of critical domain
knowledge for PM2.5 forecasting and develop a novel graph based model,
PM2.5-GNN, being capable of capturing long-term dependencies. On a real-world
dataset, we validate the effectiveness of the proposed model and examine its
abilities of capturing both fine-grained and long-term influences in PM2.5
process. The proposed PM2.5-GNN has also been deployed online to provide free
forecasting service.Comment: Pre-print version of a ACM SIGSPATIAL 2020 poster
[paper](https://dl.acm.org/doi/10.1145/3397536.3422208). The code is
available at [Github](https://github.com/shawnwang-tech/PM2.5-GNN), and the
talk is available at [YouTube](https://www.youtube.com/watch?v=VX93vMthkGM
Distribution, occurrence characteristics and geological origin of typical hazardous elements in low-medium ash coal of Huainan coalfield
With the continuous development, processing and utilization of coal resources in our province, the existence of typical harmful elements in coal is bound to have a negative impact on the efficient and clean utilization of coal resources. Based on the mass data analysis of typical hazardous elements in coal of Huainan coalfield, taking the main coal seams (No.13-1, No.11-2, No.8, No.6, No.4 and No.1) as the research objects, the occurrence characteristics and geological genesis of typical hazardous elements were comprehensively analyzed by the means of ICP-MS, AFS, stepwise chemical extraction and cluster analysis. The results were as follows: â Typical hazardous elements Cr, Co, Se and Pb in coal of Huainan coalfield are âlightly enrichedâ, Hg is âhighly enrichedâ and other elements are in ânormal rangeâ; ⥠The high value area of As element content in Huainan coalfield was mainly located in the west of coalfield; the high value region of Hg element was located in the east of coalfield, followed by the west; the remaining eight elements (Cr, Mn, Co, Ni, Se, Cd, Sb and Pb) were all higher in coal of Panji mining area of Huainan coalfield (especially near Pansan coal mine). The late magmatic hydrothermal process in Panji-Zhuji region may be the main reason for the relative enrichment of hazardous elements such as Cr, Mn, Co, Ni, Se, Cd, Sb and Pb. ⢠There were many ion-exchange States in the occurrence state of Hg, and the inorganic components brought by magmatic hydrothermal action may have little influence on the enrichment degree of Hg element. The magmatic hydrothermal intrusion in the late diagenesis period had no obvious influence on As, and the low content of As in coal may be related to the low content of As in coal-forming plants
Coâevolutionary adaptations of Acinetobacter baumannii and a clinical carbapenemaseâencoding plasmid during carbapenem exposure
Abstract: OXAâ23 is the predominant carbapenemase in carbapenemâresistant Acinetobacter baumannii. The coâevolutionary dynamics of A. baumannii and OXAâ23âencoding plasmids are poorly understood. Here, we transformed A. baumannii ATCC 17978 with pAZJ221, a blaOXAâ23âcontaining plasmid from clinical A. baumannii isolate A221, and subjected the transformant to experimental evolution in the presence of a subâinhibitory concentration of imipenem for nearly 400 generations. We used population sequencing to track genetic changes at six time points and evaluated phenotypic changes. Increased fitness of evolving populations, temporary duplication of blaOXAâ23 in pAZJ221, interfering allele dynamics, and chromosomal locusâlevel parallelism were observed. To characterize genotypeâtoâphenotype associations, we focused on six mutations in parallel targets predicted to affect small RNAs and a cyclic dimeric (3Ⲡâ 5â˛) GMPâmetabolizing protein. Six isogenic mutants with or without pAZJ221 were engineered to test for the effects of these mutations on fitness costs and plasmid kinetics, and the evolved plasmid containing two copies of blaOXAâ23 was transferred to ancestral ATCC 17978. Five of the six mutations contributed to improved fitness in the presence of pAZJ221 under imipenem pressure, and all but one of them impaired plasmid conjugation ability. The duplication of blaOXAâ23 increased host fitness under carbapenem pressure but imposed a burden on the host in antibioticâfree media relative to the ancestral pAZJ221. Overall, our study provides a framework for the coâevolution of A. baumannii and a clinical blaOXAâ23âcontaining plasmid in the presence of imipenem, involving early blaOXAâ23 duplication followed by chromosomal adaptations that improved the fitness of plasmidâcarrying cells
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