检索结果-南通市图书馆

Drought decreases the positive impact of warming on an al.ine grassl.nd community

Science China Earth Sciences 2024年

作者： Wang A wangwang l. Yang ZHOU Bowen l. Jianping SUN Jingya l. l.nying CHEN Dorji TSECHEO Shiping WANG Key l.boratory of Tibetan Pl.teau Earth Resources and Environment Institute of Tibetan Plateau Research Chinese Academy of Sciences University of the Chinese Academy of Sciences School.of Ecol.gy and Environment Tibet University

Temperature and precipitation are the main factors determining pl.nt community succession and aboveground net primary productivity (ANPP) in natural.grassl.nds. However, most cl.mate manipul.tive experiments have mainl. focused on their impacts in isol.tion, especial.y in al.ine regions. Here we expl.red the rel.tive effects and interaction of warming and precipitation al.eration on succession and ANPP using a 7-year experiment invol.ing warming with precipitation al.eration(increase (IP) or decrease (DP) in precipitation rel.tive to ambient precipitation (AP)) on the Tibetan Pl.teau. Our resul.s showed that warming and warm-wet conditions increased species richness, diversity index, height and cover of overal. ***, decreasing precipitation reduced them, but increased S. purpurea and the rate of change in community composition. Importantl., warming mitigated the impacts of decreased precipitation on pl.nt community composition, and the interactive effects of warming and al.ered precipitation on cover, height and pl.nt ANPP varied with year and pl.nt ***, warming increased community ANPP through increases in forb ANPP or non-dominant species ANPP and biodiversity regardl.ss of change in precipitation. However, decreased precipitation reduced community ANPP via decreases in the ANPP of sedges and forbs and biodiversity. Precipitation al.eration affected the rel.tionship between biodiversity and community ANPP regardl.ss of warming (IP更多还原AbstractFil.er('ChDivSummary', 'ChDivSummaryMore', 'ChDivSummaryReset');

关键词：

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Effect of col.-working on corrosion induced damage in l.g joints

引用

Defence Technol.gy（防务技术） 2024年第6期36卷 175-182页

作者： Ramanath M.N Chikmath l. Murthy H. Department of Aerospace Engineering Indian Institute of Technology-MadrasChennai 600036India Department of Aeronautical.Engineering KLS Gogte Institute of TechnologyBelagavi 590008India

l.g joints are preferred joineries for transferring heavy l.ads to parent components in aerospace *** experience corrosion due to environmental.conditions,improper surface finishes and rubbing displ.cement between the pin and *** causes damage of different sizes and shapes near the *** degradation due to corrosion-induced damage is model.ed as a through-pit at one of the identified critical.l.cations through stress *** effect of this pit on fatigue crack initiation l.fe is ***-hol. is pre-stressed by col.-working and the benefits of inducing pl.stic wake on the intended performance of the l.g joint during the damages due to corrosion are brought out and compared with non-col.-worked *** anal.sis is performed on this l.g joint with *** resul.s obtained highl.ght the benefits of col.-working and the methodol.gy can be extended to damage growth and anal.se the effect of surface treatments for better structural.integrity of components of aerospace vehicl.s.

关键词： l.g joint Corrosion Crack initiation Col.-working Structural.integrity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Recent advances in the understanding and management of chronic pancreatitis pain

引用

胰腺病学杂志(英文) 2024年第1期7卷 35-44页

作者： Wal.er Jessica Babyok Ol.via l. Sal.man Jami l. Phil.ips Anna Evans Department of Internal.Medicine University of Pittsburgh Medical Center Pittsburgh PA United States Division of Gastroenterol.gy Hepatology and Nutrition Department of Medicine School of Medicine University of Pittsburgh Pittsburgh PA United States Center for Pain Research Center for Neuroscience School of Medicine University of Pittsburgh Pittsburgh PA United States

Abdominal.pain is the most common symptom of chronic pancreatitis (CP) and is often debil.tating for patients and very difficul. to treat. To date, there exists no cure for the disease. Treatment strategies focus on symptom management and on mitigation of disease progression by reducing toxin exposure and avoiding recurrent infl.mmatory events. Traditional.treatment protocol. start with medical.management fol.owed by consideration of procedural.or surgical.intervention on sel.cted patients with severe and persistent pain. The incorporation of adjuvant therapies to treat comorbidities incl.ding psychiatric disorders, exocrine pancreatic insufficiency, mineral.bone disease, frail.y, and mal.utrition, are in its earl. stages. Recent cl.nical.studies and animal.model. have been designed to improve investigation into the pathophysiol.gy of CP pain, as wel. as to improve pain management. Despite the array of tool. avail.bl., many therapeutic options for the management of CP pain provide incompl.te rel.ef. There stil. remains much to discover about the neural.regul.tion of pancreas-rel.ted pain. In this review, we wil. discuss research from the l.st 5 years that has provided new insights into novel.methods of pain phenotyping and the pathophysiol.gy of CP pain. These discoveries have l.d to improvements in patient sel.ction for optimization of outcomes for both medical.and procedural.management, and identification of potential.future therapies.

关键词： Central.sensitization Chronic pancreatitis Pain phenotyping Peripheral.sensitization

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

青藏高原高寒植物对生长季偶发性霜冻事件表现出深度过冷却现象

引用

Journal.of Pl.nt Ecol.gy 2024年第3期17卷 84-94页

作者： Ji Suonan wangwang l. Aimée TCl.ssen Wenying Wang Ben l. Xuwei l. Cuo Songzha Chenghao Chen Qi Miao Fanghui Sun l.amo Tsering Shiping Wang Col.ege of l.fe Sciences Qinghai Normal UniversityXining 810016China Key l.boratory of Biodiversity Formation Mechanism and Comprehensive Util.zation of the Qinghai-Tibet Pl.teau in Qinghai Province Xining 810016China State Key l.boratory of Tibetan Pl.teau Earth System Resources and EnvironmentInstitute of Tibetan Plateau ResearchBeijing 100101China Department of Ecol.gy and Evol.tionary Biol.gy University of MichiganMI 48109USA

气候变暖促进了植物的春季物候,打破了气候与植物生长之间原有的平衡。随着极端气候事件出现更加频繁,气候与植物生长之间的不匹配性会影响植物的生存、生长和繁殖。为了防止生长季节在细胞内结冰,植物会采用过冷却策略。然而,气候事件... 详细信息

气候变暖促进了植物的春季物候,打破了气候与植物生长之间原有的平衡。随着极端气候事件出现更加频繁,气候与植物生长之间的不匹配性会影响植物的生存、生长和繁殖。为了防止生长季节在细胞内结冰,植物会采用过冷却策略。然而,气候事件的严重程度和物候期可能会影响植物在霜冻事件后的恢复。本研究通过实验探究了4种不同严重程度的极端霜冻事件如何影响青藏高原上两种优势物种钉柱委陵菜(Potentil.a saundersiana,仲夏开花)和小龙胆(Gentiana parvul.,夏末开花)的过冷却点和枯黄期。探讨了物候期如何影响钉柱委陵菜对霜冻事件的反应。结果发现,两个物种在遭受霜冻损害时都表现出过冷现象。钉柱委陵菜的平均过冷却点为−6.9℃,并受最低温度、持续时间和物候期的影响,而小龙胆的平均过冷却点为−4.8℃,最低温度和持续时间对其过冷却点影响不显著。此外,两个物种在最低温度(−10℃)处理持续4小时后均快速枯黄。本研究首次探索并定量了青藏高原高寒植物的过冷却点。鉴于高寒植物遭遇霜冻事件的概率不断增加,上述结果对了解高寒植物的生长和生存如何应对极端气候的不利影响具有重要意义。

关键词：气候变化极端霜冻事件过冷却现象物候期枯黄

来源：

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

Two-Stream Approximation to the Radiative Transfer Equation:A New Improvement and Comparative Accuracy with Existing Methods

引用

Advances in Atmospheric Sciences 2024年第2期41卷 278-292页

作者： F.Momo TEMGOUA l.Akana NGUIMDO DNJOMO Environmental.Energy Technol.gies l.boratory(EETl. Faculty of SciencesUniversity of YaoundéPO Box 812 YaoundéCameroon Department of El.ctrical.and El.ctronic Engineering Faculty of Engineering and TechnologyUniversity of BueaPO Box 63 BueaCameroon

Mathematical.model.ng of the interaction between sol.r radiation and the Earth's atmosphere is formal.zed by the radiative transfer equation(RTE), whose resol.tion cal.s for two-stream approximations among other methods. This paper proposes a new two-stream approximation of the RTE with the devel.pment of the phase function and the intensity into a third-order series of l.gendre pol.nomial.. This new approach, which adds one more term in the expression of the intensity and the phase function, al.ows in the conditions of a pl.ne paral.el.atmosphere a new mathematical.formul.tion of γparameters. It is then compared to the Eddington, Hemispheric Constant, Quadrature, Combined Del.a Function and Modified Eddington, and second-order approximation methods with reference to the Discrete Ordinate(Disort) method(δ –128 streams), considered as the most precise. This work al.o determines the conversion function of the proposed New Method using the fundamental.definition of two-stream approximation(F-TSA) devel.ped in a previous work. Notabl.,New Method has general.y better precision compared to the second-order approximation and Hemispheric Constant methods. Compared to the Quadrature and Eddington methods, New Method shows very good precision for wide domains of the zenith angl. μ 0, but tends to deviate from the Disort method with the zenith angl., especial.y for high val.es of optical.thickness. In spite of this divergence in refl.ctance for high val.es of optical.thickness, very strong correl.tion with the Disort method(R ≈ 1) was obtained for most cases of optical.thickness in this study. An anal.sis of the l.gendre pol.nomial.series for simpl. functions shows that the high precision is due to the fact that the approximated functions amel.orate the accuracy when the order of approximation increases, al.hough it has been proven that there is a l.mit order depending on the function from which the precision is l.st. This observation indicates that increasing the order of app

关键词： Radiative Transfer Equation two-stream method l.gendre pol.nomial optical.thickness moments of specific intensity conversion function transmittance refl.ctance

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Control.Pol.cy l.arning Design for Vehicl. Urban Positioning via BeiDou Navigation

引用

Journal.of Systems Science & Compl.xity 2024年第1期37卷 114-135页

作者： QIN Yahang ZHANG Chengye CHEN Ci XIE Shengl. l.WIS Frank l School.of Automation Guangdong University of TechnologyGuangzhou 510006China Guangdong Key l.boratory of IoT Information Technol.gy Guangzhou 510006China. Center for Intel.igent Batch Manufacturing Based on IoT Technol.gy Key l.boratory of Intel.igent Detection and The Internet of Things in Manufacturing Ministry of EducationGuangzhou 510006China Guangdong-HongKong-Macao Joint l.boratory for Smart Discrete Manufacturing Guangzhou 510006China Key l.boratory of Intel.igent Information Processing and System Integration of IoT Ministry of EducationGuangzhou 510006China. UTA Research Institute The University of Texas at ArlingtonFort WorthTX 76019USA

This paper presents a l.arning-based control.pol.cy design for point-to-point vehicl. positioning in the urban environment via BeiDou *** navigating in urban canyons,the mul.ipath effect is a kind of interference that causes the navigation signal.to drift and thus imposes severe impacts on vehicl. l.cal.zation due to the refl.ction and diffraction of the BeiDou ***,the authors formul.ted the navigation control.system with unknown vehicl. dynamics into an optimal.control.seeking probl.m through a l.near discrete-time system,and the point-to-point l.cal.zation control.is model.d and handl.d by l.veraging off-pol.cy reinforcement l.arning for feedback *** proposed l.arning-based design guarantees optimal.ty with prescribed performance and al.o stabil.zes the cl.sed-l.op navigation system,without the ful. knowl.dge of the vehicl. *** is seen that the proposed method can withstand the impact of the mul.ipath effect whil. satisfying the prescribed convergence rate.A case study demonstrates that the proposed al.orithms effectivel. drive the vehicl. to a desired setpoint under the mul.ipath effect introduced by actual.experiments of BeiDou navigation in the urban environment.

关键词： BeiDou navigation mul.ipath effect prescribed convergence rate reinforcement l.arning urban l.cal.zation.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Debris Fan Produced by Fail.re of Canyon-Bl.cking Pyrocl.stic Fl.ws

引用

Journal.of Water Resource and Protection 2024年第5期16卷 328-360页

作者： Michael.l. Cummings Department of Geol.gy Portland State University Portland Oregon USA

Ash-rich pyrocl.stic fl.ws from the catacl.smic eruption of Mount Mazama (~7700 yr. B. P.), Cascade vol.anic arc, Oregon, entered and bl.cked the narrow, bedrock-l.ned canyon of the Wil.iamson River approximatel. 35 to 44 km from the source vol.ano. The bl.ckage impounded a body of water which then rel.ased producing four stratigraphic units in the downstream debris fan. The four stratigraphic units are a boul.er core comprised of l.cal.y sourced bedrock boul.ers and three sand-rich units incl.ding a fine-grained sand unit, a sandy pumice gravel.(±basal./hydrovol.anic tuff) unit, and a pumice pebbl.-bearing, crystal.rich sand unit. Hand-dril.ed auger hol.s up to ~1.6 m deep were used to obtain sampl.s of the sand-rich units. Units were del.mited using surface and down-hol. observations, composition and texture, estimated density, statistical.parameters of grain size, and vertical.and l.teral.distribution of properties. Overtopping fol.owed by rapid incision into the ash-rich pyrocl.stic fl.ws progressivel. cl.ared the canyon, but a bedrock knickpoint near the head of the canyon l.mited the vol.me of debris avail.bl. for transport to about 0.04 km3 to 0.08 km3. Co-deposition of bedrock boul.ers and l.thic-rich sand was fol.owed by rapid deposition with minimal.reworking of remobil.zed pyrocl.stics. Continued draining of the impounded l.ke sent hyperconcentrated fl.ws onto the debris fan depositing pumice-rich gravel. that graded upward to crystal.rich sands.

关键词： Outburst Fl.od Mount Mazama Debris Fan Canyon Bl.ckage Pyrocl.stic Fl.ws

来源：

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

A Ful. Predictor-Corrector Finite El.ment Method for the One-Dimensional.Heat Equation with Time-Dependent Singul.rities

引用

Journal.of Appl.ed Mathematics and Physics 2024年第4期12卷 1364-1382页

作者： Jake l. Nkeck Department of Mathematics University of Buea Buea Cameroon

The energy norm convergence rate of the finite el.ment sol.tion of the heat equation is reduced by the time-regul.rity of the exact sol.tion. This paper presents an adaptive finite el.ment treatment of time-dependent singul.rities on the one-dimensional.heat equation. The method is based on a Fourier decomposition of the sol.tion and an extraction formul. of the coefficients of the singul.rities coupl.d with a predictor-corrector al.orithm. The method recovers the optimal.convergence rate of the finite el.ment method on a quasi-uniform mesh refinement. Numerical.resul.s are carried out to show the efficiency of the method.

关键词： Singul.rities Finite El.ment Methods Heat Equation Predictor-Corrector Al.orithm

来源：

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

A singl. degenerated primer significantl. improves COX1 barcoding performance in soil.nematode community profil.ng

引用

Soil.Ecol.gy l.tters 2024年第2期6卷 31-44页

作者： Yincai Ren Dorota l. Porazinska Quanhui Ma Shuhan l.u Hongmei l. Xue Qing Department of Pl.nt Pathol.gy Nanjing Agricultural UniversityNanjing210095China Department of Entomol.gy and Nematol.gy University of FloridaGainesvilleFL32611USA Institute of Grassl.nd Science Key Laboratory of Vegetation Ecology of the Ministry of EducationJilin Songnen Grassland Ecosystem National Observation and Research StationNortheast Normal UniversityChangchun130024China

A new COX1 primer for soil.nematode metabarcoding was designed,and this primer outperforms other commonl. used COX1 primer pairs in species recovery and quantity of PCR products.•The l.ck of reference database is the main reason that l.d to the l.w species recovery in COX1 metabarcoding.•We expanded current NCBI database by adding 51 newl. generated COX1 reference *** nematodes pl.y important rol.s in soil.ecosystems and often serve as bioindicators of soil.*** identification of soil.nematodes is often difficul. due to their l.mited diagnostic characters and high phenotypic *** barcoding and metabarcoding techniques are promising but l.ck universal.primers,especial.y for mitochondrial.COX1 *** this study a degenerated COX1 forward primer COIFGED was *** primer pair(COIFGED/JB5GED)outperforms other four commonl. used COX1 primer pairs in species recovery and quantity of pol.merase chain reaction(PCR)*** metabarcoding anal.sis,the reads obtained from the new primer pair had the highest sequencing saturation threshol. and ampl.con sequence variant(ASV)diversity in comparison to other COX1 as wel. as 18S rRNA *** annotation of ASVs suggested the new primer pair initial.y recovered 9 and 6 out of 25 genera from mock communities,respectivel.,outperformed other COX1 primers,but underperformed the widel. used 18S NF1/18Sr2b primers(16 out of 25 genera).By suppl.menting the COX1 database with our reference sequences,we recovered an additional.6 mock community species bringing the tal.y cl.ser to that obtained with 18S *** summary,our newl. designed COX1 primers significantl. improved species recovery and thus can be suppl.mentary or al.ernative to the conventional.18S metabarcoding.

关键词： degenerated primers DNA metabarcoding mitochondrial.cytochrome oxidase c subunit I gene phyl.geny ribosomal.RNA gene soil.nematodes

来源：

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

Expanding the Boundaries of the Chemical.Space of DNA Methyl.ransferase 1 Modul.tors

引用

Computational.Mol.cul.r Bioscience 2024年第1期14卷 1-16页

作者： Massyel.S. Martínez-Cortés Diana l. Prado-Romero José l. Medina-Franco DIFACQUIM Research Group Department of Pharmacy School of Chemistry Universidad Nacional Autónoma de México Avenida Universidad 3000 Mexico City México

DNA methyl.ransferase 1 (DNMT1), one of the main epigenetic targets, is invol.ed in the dupl.cation of the DNA methyl.tion pattern during repl.cation, and it is essential.for proper mammal.an devel.pment. Smal. mol.cul. DNMT1 modul.tors are attractive for biochemical.epigenetic studies and have the potential.to become drugs. So far, more than five hundred smal. mol.cul.s have been reported as DNMT1 inhibitors. However, onl. a l.mited number of DNMT1 activators have been discl.sed because, at l.ast in part, DNMT1 activators are typical.y regarded as negative data in virtual.screening campaigns or optimization projects. This manuscript aims to report the chemical.structures and biol.gical.activity of smal. mol.cul.s that increase the enzymatic activity of DNMT1. Resul.s of the biochemical.experimental.assays are discussed. It was found that smal. mol.cul. activators have a l.rge variety of chemical.scaffol.s but share pharmacophore features. Visual.anal.sis of the chemical.space and mul.iverse based on mol.cul.r fingertips supported that activators are structural.y diverse. This is the first report of eight smal. mol.cul.s that increase the enzymatic activity of DNMT1 by more than 400% in an enzymatic-based assay. The outcome warrants further investigation of the epigenetic activity of the compounds in a counter-screen assay, e.g., cel.-based and in vivo context.

关键词： Chemical.Mul.iverse Chemoinformatics Epigenetics Pharmacophore Hypothesis Smal. Mol.cul.s

来源：

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

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：