检索结果-南通市图书馆

Summary of a Life in Observational Ultraviolet/Optical Astronomy

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research in Astronomy and Astrophysics 2024年第1期24卷 1-43页

作者： donald G.York Department of Astronomy and Astrophysics The University of Chicago5801 South Ellis Ave.Chicago 60637ILUSA

I reminisce on my early life in Section 1;on my education in Sections 2 and 3;on the years at Princeton as a research astronomer in Section 4;on the years on the faculty at Chicago in Section 5;on research on Diffuse Interstellar Bands(DIBs) in Section 6;on construction of the 3.5 m telescope at Apache Point Observatory(APO)in Section 7;on work on the Sloan Digital Sky Survey(SDSS) in Section 8;on work in public education in Chicago in Section 9;and on my travels in Section 10. My main science research is of an observational nature,concerning Galactic and intergalactic interstellar gas. highlights for me included my work on the orbiting telescope Copernicus, including the discovery of interstellar deuterium;early observations of absorption associated with fivetimes ionized oxygen;and discoveries concerning the phases of gas in the local interstellar medium, based on previously unobservable interstellar UV spectral lines. With other instruments and collaborations, I extended interstellar UV studies to the intergalactic cool gas using quasi-stellar object QSO absorption lines redshifted to the optical part of the spectrum;provided a better definition of the emission and morphological character of the source of absorption lines in QSO spectra;and pursued the identification of the unidentified DIBs. For several of these topics, extensive collaborations with many scientists were essential over many years. The conclusions developed slowly, as I moved from being a graduate student at Chicago, to a research scientist position at Princeton and then to a faculty position at Chicago. At each stage of life, I was exposed to new technologies adaptable to my science and to subsequent projects. From high school days, I encountered several management opportunities which were formative. I have been extremely fortunate both in scientific mentors I had and in experimental opportunities I encountered.

关键词： Interstellar Medium(ISM) Nebulae (galaxies:)quasars:absorption lines ultraviolet:stars

Tanaka Formula and Local Time for a Class of Interacting Branching Measure-valued Diffusions

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2024年第4期40卷 1059-1098页

作者： donald A.DAWSON Jean VAILLANCOURT hao WANG School of Mathematics and Statistics Carleton UniversityOttawaCanada Department of Decision Sciences HECMontrealCanada Department of Mathematics University of OregonEugeneUSA

We construct superprocesses with dependent spatial motion(SDSMs)in Euclidean spaces R^(d)with d≥1 and show that,even when they start at some unbounded initial positive Radon measure such as Lebesgue measure on R^(d),... 详细信息

关键词： Measure-valued diffusions stochastic partial differential equations superprocesses branching processes local time Tanaka formula

Origins of the problematic E in SEIR epidemic models

在线全文

学校读者我要写书评

暂无评论

Infectious Disease Modelling 2024年第3期9卷 673-679页

作者： donald S.Burke Distinguished University Professor Emeritus of health Science and Policy Department of EpidemiologySchool of Public HealthUniversity of PittsburghUSA

During the COVID-19 pandemic,over one thousand papers were published on“Susceptible-Exposed-Infectious-Removed”(SEIR)epidemic computational *** English word“exposed”in its vernacular and public health usage means a state of having been in contact with an infectious individual,but not necessarily *** contrast,the term“exposed”in SEIR modeling usage typically stands for a state of already being infected but not yet being infectious to others,a state more properly termed“latently infected.”In public health language,“exposed”means possibly infected,yet in SEIR modeling language,“exposed”means already *** paper retraces the conceptual and mathematical origins of this terminological disconnect and concludes that epidemic modelers should consider using the“SLIR”notational short-hand(L for Latent)instead of SEIR.

关键词： SEIR model Exposed Latent infection history Notation

Calibration of the DEM sliding friction and rolling friction parameters of a cohesionless bulk material

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第9期92卷 126-139页

作者： Jonatan Marín Pérez Tugrul Comlekci Yevgen Gorash donald MacKenzie University of Strathclyde 75 Montrose StreetG11XJGlasgowUnited Kingdom

The discrete element method(DEM)has become a valuable tool for understanding the mechanical behaviour of granular assemblies,however,the accuracy of the DEM simulations depends on several interaction parameters such as the sliding friction and rolling friction ***,these parameters are estimated using bulk calibration approach(BCA)where the draw down test has been suggested as an effective way to approach these *** test provides up to four bulk criteria,the angle of repose,shear angle,mass flow rate and the mass loss which are used to narrow down the possible ***,there is still more research needed around it to fully understand how this methodology *** experimental and numerical study was carried out using the draw down test to assess the influence of different mass flow rates and particle shapes on DEM parameters for a cohesionless bulk *** is concluded that use of multi-sphere particles and three aperture sizes in the draw down test to calibrate the sliding and rolling friction parameters of a cohesionless bulk material can converge to a small feasible region in which a single combination of the friction coefficients can be *** calibrated sliding and rolling friction coefficients were validated using multi-sphere particles,where the maximum deviation was 5.9%from the experimental values.

关键词： Discrete element method Calibration Draw down Sliding friction Rolling friction Particle shape

Unimolecular Reactions of E-Glycolaldehyde Oxide and Its Reactions with One and Two Water Molecules

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Research 2024年第1期2023卷 809-824页

作者： Yan Sun Bo Long donald G.Truhlar Department of Physics Guizhou UniversityGuiyang 550025China College of Materials Science and Engineering Guizhou Minzu UniversityGuiyang 550025China Department of Chemistry Chemical Theory Centerand Supercomputing InstituteUniversity of MinnesotaMinneapolisMN 55455-0431USA

The kinetics of Criegee intermediates are important for atmospheric ***,the quantitative kinetics of Criegee intermediates are still very limited,especially for those with hydroxy ***,we calculate rate constants for the unimolecular reaction of E-glycolaldehyde oxide[E-hydroxyethanal oxide,E-(Ch_(2)Oh)ChOO],for its reactions with h_(2)O and(h_(2)O)_(2),and for the reaction of the E-(Ch_(2)Oh)ChOO…h_(2)O complex with h_(2)*** the highest level of electronic structure,we use W3X-L//CCSD(T)-F12a/cc-pVDZ-F12 for the unimolecular reaction and the reaction with water and W3X-L//DF-CCSD(T)-F12b/jun-cc-pVDZ for the reaction with 2 water *** the dynamics,we use a dual-level strategy that combines conventional transition state theory with the highest level of electronic structure and multistructural canonical variational transition state theory with small-curvature tunneling with a validated density functional for the electronic structure.

关键词： structure kinetics molecular

Ripening and rot:how ripening processes influence disease susceptibility in fleshy fruits

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 Integrative Plant Biology 2024年第9期66卷 1831-1863页

作者： Shan Li Yu Zhao Pan Wu donald Grierson Lei Gao State Key Laboratory of Plant Diversity and Specialty Crops Wuhan Botanical GardenChinese Academy of SciencesWuhan 430074China University of Chinese Academy of Sciences Beijing 100049China Plant and Crop Sciences Division School of BiosciencesUniversity of NottinghamSutton Bonington CampusLoughboroughLE125RDUK hubei hongshan Laboratory Wuhan 430070China

Fleshy fruits become more susceptible to pathogen infection when they ripen;for example,changes in cell wall properties related to softening make it easier for pathogens to infect *** need for high-quality fruit has driven extensive research on improving pathogen resistance in important fruit crops such as tomato(Solanum lycopersicum).In this review,we summarize current progress in understanding how changes in fruit properties during ripening affect infection by *** changes affect physical barriers that limit pathogen entry,such as the fruit epidermis and its cuticle,along with other defenses that limit pathogen growth,such as preformed and induced defense *** plant immune system also protects ripening fruit by recognizing pathogens and initiating defense responses involving reactive oxygen species production,mitogen-activated protein kinase signaling cascades,and jasmonic acid,salicylic acid,ethylene,and abscisic acid *** phytohormones regulate an intricate web of transcription factors(TFs)that activate resistance mechanisms,including the expression of pathogenesis-related *** tomato,ripening regulators,such as RIPENING INhIBITOR and NON_RIPENING,not only regulate ripening but also influence fruit defenses against ***,members of the EThYLENE RESPONSE FACTOR(ERF)family play pivotal and distinct roles in ripening and defense,with different members being regulated by different *** also discuss the interaction of ripening-related and defense-related TFs with the Mediator transcription *** the ripening processes in climacteric and non-climacteric fruits share many similarities,these processes have broad applications across fruiting *** research on the individual contributions of ERFs and other TFs will inform efforts to diminish disease susceptibility in ripe fruit,satisfy the growing demand for high-quality fruit and decrease food waste and related economic losses.

关键词： fleshy fruit pathogen phytohormones ripening transcription factors

Ferroptosis in liver diseases:Fundamental mechanism and clinical implications

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2024年第32期30卷 3730-3738页

作者： Ming-Shuang Lai Xi-Peng Yan donald R Branch Melika Loriamini Li-Min Chen The Joint Laboratory on Transfusion-Transmitted Diseases(TTDs)Between Institute of Blood Transfusion Chinese Academy of Medical Sciences and Nanning Blood CenterNanning 530003Guangxi Zhuang Autonomous RegionChina Department of Medicine and Laboratory Medicine and Pathobiology Centre for InnovationCanadian Blood ServicesHamilton 397086Canada Institute of Blood Transfusion Chinese Academy of Medical Sciences and Peking Union Medical CollegeKey Laboratory for Transfusion-transmitted Infectious Diseases of the Health Commission of Sichuan ProvinceChengdu 610052Sichuan ProvinceChina

This editorial discusses a recently published paper in the World Journal of *** research focuses on p53's regulatory mechanism for controlling ferroptosis,as well as the intricate connection between ferroptosis and liver *** is a specific form of programmed cell death that is dependent on iron and displays unique features in terms of morphology,biology,and genetics,distinguishing it from other forms of cell *** can affect the liver,which is a crucial organ responsible for iron storage and *** evidence indicates a robust correlation between ferroptosis and the advancement of liver disorders.P53 has a dual effect on ferroptosis through various distinct signaling ***,additional investigations are required to clarify the regulatory function of p53 metabolic targets in this complex association with *** the future,researchers should clarify the mechanisms by which ferroptosis and other forms of programmed cell death contribute to the progression of liver *** and controlling important regulatory factors associated with ferroptosis present a promising therapeutic strategy for liver disorders.

关键词： Liver disease P53 Programmed cell death Ferroptosis Therapeutic target

Twin Paradox and Proper Time

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 Applied Mathematics and Physics 2024年第1期12卷 12-15页

作者： donald Lem White Plains NY USA

Professors Mohazzbi and Luo [1] published “Despite several attempts have been made to explain the twin paradox … none of the explanations … resolved the paradox. If the paradox can be ever resolved, it requires a much deeper understanding … of the theory of relativity”. The deeper understanding of resolving the paradox is by applying more explicit definitions of proper time interval, Lorentz transform, time dilation, and aging time.

关键词： Twin Paradox Proper Time Minkowski Metric Schwarzschild Metric

Free vibration and buckling analysis of polymeric composite beams reinforced by functionally graded bamboo fbers

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 543-562页

作者： h.M.FEIZABAD M.h.YAS Department of Mechanical Engineering Razi UniversityKermanshah ***Iran

Natural fibers have been extensively researched as reinforcement materials in polymers on account of their environmental and economic advantages in comparison with synthetic fibers in the recent *** fibers are renowned for their good mechanical properties,abundance,and short cycle *** beams are one of the fundamental structural components and are susceptible to mechanical loads in engineering applications,this paper performs a study on the free vibration and buckling responses of bamboo fiber reinforced composite(BFRC)beams on the elastic *** different functionally graded(FG)layouts and a uniform one are the considered distributions for unidirectional long bamboo fibers across the *** elastic properties of the composite are determined with the law of *** hamilton’s principle,the governing equations of motion are *** generalized differential quadrature method(GDQM)is then applied to the equations to obtain the *** achieved outcomes exhibit that the natural frequency and buckling load values vary as the fiber volume fractions and distributions,elastic foundation stiffness values,and boundary conditions(BCs)and slenderness ratio of the beam ***,a comparative study is conducted between the derived analysis outcomes for BFRC and homogenous polymer beams to examine the effectiveness of bamboo fibers as reinforcement materials,demonstrating the significant enhancements in both vibration and buckling responses,with the exception of natural frequencies for cantilever beams on the Pasternak foundation with the FG-◇fiber ***,the obtained analysis results of BFRC beams are also compared with those for carbon nanotube reinforced composite(CNTRC)beams found in the literature,indicating that the buckling loads and natural frequencies of BFRC beams are lower than those of CNTRC beams.

关键词： bamboo fiber free vibration buckling analysis functionally graded(FG)beam elastic foundation generalized differential quadrature method(GDQM)