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CONDITIONS FOR OPTIMAL SOLUTIONS OF UNBALANCED PROCRUSTES PROBLEM ON STIEFEL MANIFOLD

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Journal of Computational Mathematics 2007年第6期25卷 661-671页

作者： Zhenyue zhang Yuyang Qiu keqin Du Department of Mathematics Zhejiang University Hangzhou 310027 China

We consider the unbalanced Procrustes problem with an orthonormal constraint on solutions： given matrices A ∈ R^n×n and B ∈ R^n×k, n 〉 k, minimize the residual ‖AQ- B‖F over the Stiefel manifold of orthonormal matrices. Theoretical analysis on necessary conditions and sufficient conditions for optimal solutions of the unbalanced Procrustes problem is given.

关键词： Procrustes problem Stiefel manifold Necessary condition Sufficient condition.

Multiple olfactory pathways contribute to the lure process of Caenorhabditis elegans by pathogenic bacteria

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Science China(Life Sciences) 2021年第8期64卷 1346-1354页

作者： Man Zhu Yao Chen Ninghui Zhao Hua Bai keqin zhang Xiaowei Huang State Key Lab for Conservation and Utilization of Bio-Resources and College of Life ScienceYunnan UniversityKunming 650091China Neurosurgery of the Second Hospital Affiliated with Kunming Medical University Kunming 650101China College of Public Health Kunming Medical UniversityKunming 650500China

Chemosensation is indispensable for the survival of Caenorhabditis elegans to discriminate food and pathogenic bacteria in their living environment. Food-like odors emitted by the pathogen Bacillus nematocida B16 for trapping its hosts and an olfactory signaling pathway responsible to sense the attractant 2-heptanone were identified in our previous study. Here, we further explore how the worms recognize the attractive molecules indole and 2-ethyl hexanol, which have different chemical properties and modest nematode-luring ability. We show that the chemotaxis toward indole and 2-ethyl hexanol requires the G protein-coupled receptors encoded by str-193 on AWC and str-7 on AWA. In a further genetic screen for downstream effectors in olfactory signaling cascades, the Gα subunit GSA-1, guanylyl cyclase ODR-1 and DAF-11 and the c GMP-gated channel TAX-2/TAX-4 were found to be necessary for indole sensation, whereas the TRPV channels OSM-9/OCR-2 and the PLC pathway activated by GPA-6 are responsible for the detection of 2-ethyl hexanol. Altogether, our current work further clarifies the distinct olfactory signaling pathways through which C. elegans senses different chemicals and is lured by B. nematocida B16, improving our comprehensive understanding of the mechanisms by which bacterial pathogens effectively infect their hosts.

关键词： attractive trapping process

Plastering mud around the entrance hole affects the estimation of threat levels from nest predators in Eurasian Nuthatches

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Avian Research 2021年第4期12卷 658-663页

作者： Jiangping Yu Li zhang Guodong Yi keqin zhang Jiyuan Yao Jian Fang Chao Shen Haitao Wang Jilin Engineering Laboratory for Avian Ecology and Conservation Genetics School of Life SciencesNortheast Normal UniversityChangchun 130024China School of Life Sciences Jilin Normal UniversitySiping 136000China School of Zoological Science Jilin Agricultural Science and Technology UniversityJilin 132109China College of Animal Science and Technology Jilin Agricultural UniversityChangchun 130118China Jilin Key Laboratory of Animal Resource Conservation and Utilization Northeast Normal UniversityChangchun 130024China

Background:For cavity-nesting birds,the nest entrance plays an important role in preventing predators from accessing *** species of nuthatches use mud to narrow the entrance of *** theory,the smaller the entrance hole size,the more effective it is against predators;however,few studies have tested whether narrowing the entrance hole size can affect the estimation of threat levels from nest predators in cavity-nesting ***:Using dummy experiments,we tested whether Eurasian Nuthatches(Sitta europaea,narrow the entrance hole of cavities)and Cinereous Tits(Parus cinereus,do not narrow the entrance hole,as a control)perform different nest defence behaviours against Common Chipmunks(Tamias sibiricus,small nest predator)and Red Squirrels(Sciurus vulgaris,larger nest predator).Results:Both nuthatches and tits exhibited stronger response behaviours(high dummy response scores)against chipmunks than against *** with tits,nuthatches exhibited more aggressive behaviours to chipmunks,but their responses to squirrels were ***:Nest defence behaviours of nuthatches to chipmunks differed from tits,and the results suggested that nuthatches might estimate threat levels of nest predators according to their narrowed entrance-hole size.

关键词： Cavity-nesting birds Entrance-hole size Eurasian Nuthatches Nest defence behaviour Nest predator

Does social information affect the settlement decisions of resident birds in their second breeding attempt?A case study of the Japanese Tit(Parus minor)

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Avian Research 2024年第3期15卷 326-335页

作者： Xudong Li Jiangping Yu Dake Yin Longru Jin keqin zhang Li Shen Zheng Han Haitao Wang Jilin Enginering Labonatony for Arian Eecology ani Comsenvanion Garetis School of Lfe S&ciencesNorthaust Normal UnvesityGhangchuan130024China School of Bcology and Ervirormnt Baotou Toachars'College Baoton014000China Jilin Prorncial Key labonatary of Animal Reource Consenvation and Urlisation Northeat Normal UntversityChangchun130024 Chine School of Zlogicail Sciance Jhlia Agialural Scaince and Tecrhnology UnversiyJlim132109China No.87 Middle School of Changchun Changchun130062China

Individuals may gather information about environmental conditions when deciding where to breed in order to maximize their lifetime *** can obtain social information by observing conspecifics and heterospecifics with similar ecological *** studies have shown that birds can rely on social information to select their nest *** location of active nests and the reproductive success of conspecifics and heterospecifics can provide accurate predictions about the quality of the breeding *** short-lived species can facultatively reproduce two and/or more times within a breeding ***,few studies have focused on how multiplebrooding individuals select nest sites for their second breeding *** this study,we use long-term data to test whether the Japanese Tit(Parus minor)can use social information from conspecifics and/or heterospecifics(the Eurasian Nuthatch Sitta europaea,the Daurian Redstart Phoenicurus auroreus and the Yellow-rumped Flycatcher Ficedula zanthopygia)to select a nest site for the second breeding *** results showed that the nest boxes occupied by tits on their second breeding attempt tended to be surrounded by more breeding conspecific nests,successful first nests of conspecifics,and fewer failed first nests of conspecifics than the nest boxes that remained unoccupied(the control group).However,the numbers of breeding heterospecific nests,successful heterospecific nests,and failed heterospecific nests did not differ between the nest boxes occupied by tits on their second breeding attempt and the unoccupied nest ***,the tits with local successful breeding experience tended to choose areas with more successful first nests of conspecifics than those without successful breeding ***,we suggest that conspecifics'but not heterospecifics'social information within the same breeding season is the major factor influencing the nest site selection of Japanese Tits during second breeding attempts.

关键词： Conepeific Heterospecifie Japanese tits Multiple brooding Nest-site selection Public infomation Social information

Vastly Synergistic Fe_(2)CuNiS_(4)-Nanoarchitectures Anchored 2D-Nano-Sandwich Derived from Flower-Like-CuFeS_(2)/N-Graphene and Cube-Like-NiFeS_(2)/N-CNTs for Water Oxidation and Nitrophenol Reduction

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Energy & Environmental Materials 2024年第6期7卷 274-289页

作者： Gopiraman Mayakrishnan Ramkumar Vanaraj Junpeng Xiong Muhammad Farooq Azeem Ullah keqin zhang Seong Cheol Kim Ick Soo Kim Nano Fusion Technology Research Group Division of Molecules and PolymersInstitute for Fiber Engineering(IFES)Interdisciplinary Cluster for Cutting Edge Research(ICCER)Shinshu UniversityTokida 3-15-1UedaNagano 386-8567Japan School of Chemical Engineering Yeungnam UniversityGyeongsan 38541Korea Graduate School of Medicine Scienceand TechnologyShinshu UniversityTokida 3-15-1UedaNagano 386-8567Japan National Engineering Laboratory for Modern Silk College of Textile and Clothing EngineeringSoochow UniversitySuzhou 215123China

Surface area,pore properties,synergistic behavior,homogenous dispersion,and interactions between carbon matrix and metal-nanostructures are the key factors for achieving the better performance of carbon-metal based(electro)***,the traditional hydro-or solvothermal preparation of(electro)catalysts,particularly,bi-or tri-metallic nanostructures anchored graphene(G)or carbon nanotubes(CNTs),often pose to poor metal–support interaction,low synergism,and patchy *** first,bimetallic flower-like-CuFeS_(2)/NG and cube-like-NiFeS_(2)/NCNTs nanocomposites were prepared by solvothermal *** resultant bimetallic nanocomposites were employed to derive the 2D-nano-sandwiched Fe_(2)CuNiS_(4)/NGCNTs-SW(electro)catalyst by a very simple and green urea-mediated“mix-heat”*** desired physicochemical properties of Fe_(2)CuNiS_(4)/NGCNTs-SW such as multiple active sites,strong metal-support interaction,homogenous dispersion and enhanced surface area were confirmed by various microscopic and spectroscopic *** the best of our knowledge,this is the first urea-mediated“mix-heat”method for preparing 2D-nano-sandwiched carbon-metal-based(electro)*** Fe_(2)CuNiS_(4)/NGCNTs-SW was found to be highly effective for alkaline-mediated oxygen evolution reaction at low onset potential of 284.24 mV,and the stable current density of 10 mA cm^(−2) in 1.0 m KOH for 10 ***,the Fe_(2)CuNiS_(4)/NGCNTs-SW demonstrated excellent catalytic activity in the reduction of 4-nitrophenol with good kapp value of 87.71×10^(−2)s^(-1)and excellent reusability over five ***,the developed urea-mediated“mix-heat”method is highly efficient for the preparation of metal-nanoarchitectures anchored 2D-nano-sandwiched(electro)catalysts with high synergism,uniform dispersion and excellent metal-support interaction.

关键词： (electro)catalyst metal-sulfide nanoarchitectures mix-heat N-graphene/NCNTs synergistic effect urea

Zr_(41)Ti_(14)Cu_(12.5)Ni_(10)Be_(22.5)块体非晶合金结构自由体积周围化学环境的研究

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稀有金属材料与工程 2009年第8期38卷 1429-1431页

作者：张克勤燕山大学亚稳材料制备技术与科学国家重点实验室河北秦皇岛066004

采用X射线衍射(XRD)、正电子湮没技术(PAT)-多普勒展宽谱,研究Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金及其过冷液相区结构自由体积周围的元素分布。结果表明:原始制备的Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金其结构自由体积周围主要富集Z... 详细信息

采用X射线衍射(XRD)、正电子湮没技术(PAT)-多普勒展宽谱,研究Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金及其过冷液相区结构自由体积周围的元素分布。结果表明:原始制备的Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金其结构自由体积周围主要富集Zr原子,在过冷液相区(T=400℃)等温退火后,在该合金结构自由体积周围探测到Zr、Ti和Be原子。

关键词： Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金结构自由体积多普勒展宽谱化学环境

Melanin precursors mediated adaption to temperature changes in fungus and animal via inhibition of lipid-mediated ferroptosis

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Science China(Life Sciences) 2023年第8期66卷 1800-1817页

作者： Xiaoyu Yang Yonghong Chen Longlong zhang Jiangbo He Qunfu Wu Shuhong Li Donglou Wang Jianghui Gou Zhuang Wu keqin zhang Shenghong Li Xuemei Niu State Key Laboratory for Conservation and Utilization of Bio-Resources in Yunnan and Key Laboratory for Southwest Microbial Diversity of the Ministry of EducationYunnan UniversityKunming 650032China State Key Laboratory of Phytochemistry and Plant Resources in West China Kunming Institute of BotanyChinese Academy of SciencesKunming 650201China Kunming Key Laboratory of Respiratory Disease Kunming UniversityKunming 650214China

The discovery of biological activities of natural products plays a vital part in drug *** mechanism by which organisms respond to temperature changes via biosynthesis of natural products remained largely cryptic.A thermophilic fungus under cold stress turned black and accumulated a polyketide metabolite 1 and lipid *** in 1 caused melanin loss and accumulated extra lipid mass,unexpectedly leading to seriously damaged mitochondria diagnostic for *** analysis revealed that lipid mass induced by cold stress intensively increased ferroptosis risk and 1 functioned as cell wall reinforcer against mass lipid accumulation and as reactive oxygen species scavenger against lipid *** also found that melanin in mice lowered lipid level but enhanced animal resistance to cold *** with melanin precursors significantly increased mouse cell survival rate under cold *** results unveiled a metabolite-lipid-ferroptosis-cold relationship,which provided mechanistic insights into the functions of most common metabolites and into diseases related to cold *** findings opened a perspective for developing anti-cold and anti-ferroptosis therapeutics and agents.

关键词： melanin precursor lipid ferroptosis temperature change anti-cold

正电子湮没技术研究Zr_(41)Ti_(14)Cu_(12.5)Ni_(10)Be_(22.5)块体非晶合金的结构自由体积

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稀有金属材料与工程 2011年第1期40卷 45-47页

作者：张克勤燕山大学亚稳材料制备技术与科学国家重点实验室河北秦皇岛066004

采用X射线衍射(XRD)仪、正电子湮没光谱(PAT)研究Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金的结构特性。结果表明:原始制备的Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金其正电子湮没寿命为176ps(大于正电子在纯铁中点阵空位上湮没的寿命τVFe=1... 详细信息

采用X射线衍射(XRD)仪、正电子湮没光谱(PAT)研究Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金的结构特性。结果表明:原始制备的Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金其正电子湮没寿命为176ps(大于正电子在纯铁中点阵空位上湮没的寿命τVFe=165ps)。在过冷液区(T=400℃)等温退火中,正电子湮没寿命随着退火时间的增加而减小。在过冷液区退火,导致Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金的结构更致密。

关键词： Zr41Ti14Cu12.5Ni10Be22.5块体非晶合金过冷液区结构自由体积正电子湮没寿命

Economic Policy Uncertainty,Geopolitical Risk and China's Energy Price

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Economic Policy Uncertainty,Geopolitical Risk and China's En...