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The great catastrophe: causes of the Permo-Triassic marine mass extinction

National science Review 2024年第1期11卷 37-50页

作者： Paul B.Wignall David P.g.Bond school of Earth & Environment University of Leeds school of Environmental sciences University of Hull

The marine losses during the Permo-Triassic mass extinction were the worst ever experienced. All groups were badly affected, especially amongst the benthos(e.g. brachiopods, corals, bryozoans, foraminifers,ostracods). Planktonic populations underwent a fundamental change with eukaryotic algae being replaced by nitrogen-fixing bacteria, green-sulphur bacteria, sulphate-reducing bacteria and prasinophytes. Detailed studies of boundary sections, especially those in south China, have resolved the crisis to a ～55 kyr interval straddling the Permo-Triassic boundary. Many of the losses occur at the beginning and end of this interval painting a picture of a two-phase extinction. Improved knowledge of the extinction has been supported by numerous geochemical studies that allow diverse proposed extinction mechanisms to be studied. A transition from oxygenated to anoxic-euxinic conditions is seen in most sections globally, although the intensity and timing shows regional variability. Decreased ocean ventilation coincides with rapidly rising temperatures and many extinction scenarios attribute the losses to both anoxia and high *** kill mechanisms include ocean acidification for which there is conflicting support from geochemical proxies and, even less likely, siltation(burial under a massive influx of terrigenous sediment) which lacks substantive sedimentological evidence. The ultimate driver of the catastrophic changes at the end of the Permian was likely siberian Trap eruptions and their associated carbon dioxide emissions with consequences such as warming, ocean stagnation and acidification. Volcanic winter episodes stemming from siberian volcanism have also been linked to the crisis, but the short-term nature of these episodes(s) and the overwhelming evidence for rapid warming during the crisis makes this an unlikely cause. Finally, whilst the extinction is well studied in equatorial latitudes, a different history is found in northern Boreal latitudes

关键词： ocean anoxia ocean acidification siltation productivity collapse volcanic winter

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Uncovering the dominant contribution of intermediate volatility compounds in secondary organic aerosol formation from biomass-burning emissions

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National science Review 2024年第3期11卷 150-158页

作者： Kun Li Jun Zhang David M.Bell Tiantian Wang Houssni Lamkaddam Tianqu Cui Lu Qi Mihnea surdu Dongyu Wang Lin Du Imad El Haddad Jay g.slowik Andre s.H.Prevot Environment Research Institute Shandong University Laboratory of Atmospheric Chemistry Paul Scherrer Institute

Organic vapors from biomass burning are a major source of secondary organic aerosols(sOAs). Previous smog chamber studies found that the sOA contributors in biomass-burning emissions are mainly volatile organic compounds(VOCs). While intermediate volatility organic compounds(IVOCs) are efficient sOA precursors and contribute a considerable fraction of biomass-burning emissions, their contribution to sOA formation has not been directly observed. Here, by deploying a newly-developed oxidation flow reactor to study sOA formation from wood burning, we find that IVOCs can contribute ～70% of the formed sOA, i.e.>2 times more than VOCs. This previously missing sOA fraction is interpreted to be due to the high wall losses of semi-volatile oxidation products of IVOCs in smog chambers. The finding in this study reveals that sOA production from biomass burning is much higher than previously thought, and highlights the urgent need for more research on the IVOCs from biomass burning and potentially other emission sources.

关键词： atmospheric chemistry biomass burning secondary organic aerosol intermediate volatility organic compounds

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Dynamic and electrical responses of a curved sandwich beam with glass reinforced laminate layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact

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Applied Mathematics and Mechanics(English Edition) 2024年第1期45卷 155-178页

作者： N.sHAHVEIsI s.FELI Department of Mechanical Engineering Razi UniversityKermanshah ***Iran

The dynamic responses and generated voltage in a curved sandwich beam with glass reinforced laminate(gRL)layers and a pliable core in the presence of a piezoelectric layer under low-velocity impact(LVI)are *** current study aims to carry out a dynamic analysis on the sandwich beam when the impactor hits the top face sheet with an initial *** the layer analysis,the high-order shear deformation theory(HsDT)and Frostig's second model for the displacement fields of the core layer are *** classical non-adhesive elastic contact theory and Hunter's principle are used to calculate the dynamic responses in terms of *** order to validate the analytical method,the outcomes of the current investigation are compared with those gained by the experimental tests carried out by other researchers for a rectangular composite plate subject to the *** element(FE)simulations are conducted by means of the ABAQUs *** effects of the parameters such as foam modulus,layer material,fiber angle,impactor mass,and its velocity on the generated voltage are reviewed.

关键词： analytical model piezoelectric layer curved sandwich beam glass reinforced laminate(gRL) pliable core low-velocity impact(LVI) classical non-adhesive elastic contact theory

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The soft X-ray Imager(sXI)on the sMILE Mission

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Earth and Planetary Physics 2024年第1期8卷 5-14页

作者： s.sembay A.L.Alme D.Agnolon T.Arnold A.Beardmore A.Belén Balado Margeli C.Bicknell C.Bouldin g.Branduardi-Raymont T.Crawford J.P.Breuer T.Buggey g.Butcher R.Canchal J.A.Carter A.Cheney Y.Collado-Vega H.Connor T.Crawford N.Eaton C.Feldman C.Forsyth T.Frantzen g.galgóczi J.garcia g.Y.genov C.gordillo H-P.gröbelbauer M.guedel Y.guo M.Hailey D.Hall R.Hampson J.Hasiba O.Hetherington A.Holland s-Y.Hsieh M.W.J.Hubbard H.Jeszenszky M.Jones T.Kennedy K.Koch-Mehrin s.Kögl s.Krucker K.D.Kuntz C.Lakin g.Laky O.Lylund A.Martindale J.Miguel Mas Hesse R.Nakamura K.Oksavik N.Østgaard H.Ottacher R.Ottensamer C.Pagani s.Parsons P.Patel J.Pearson g.Peikert F.s.Porter T.Pouliantis B.H.Qureshi W.Raab g.Randal A.M.Read N.M.M.Roque M.E.Rostad C.Runciman s.sachdev A.samsonov M.soman D.sibeck s.smit J.søndergaard R.speight s.stavland M.steller TianRan sun J.Thornhill W.Thomas K.Ullaland B.Walsh D.Walton C.Wang s.Yang school of Physics and Astronomy University of LeicesterLeicesterLE17RHUK space Park Leicester University of LeicesterLeicesterLE17RHUK Mullard space science Laboratory University College LondonDorkingRH56NTUK Centre for Electronic Imaging Open UniversityMilton KeynesMK76 AAUK Birkeland Centre for space science Department of Physics and TechnologyUniv.of BergenN-5007 BergenNorway University of Vienna A-1010 ViennaAustria space Research Institute Austrian Academy of SciencesA-8042 GrazAustria National Institute of Aerospace Technology MadridSpain EsTEC European Space Agency2201 AZ NoordwijkNetherlands state Key Laboratory of space Weather National Space Science CentreBeijing 100190China University of Applied sciences and Arts Northwestern switzerland CH-5210 WindischSwitzerland Koegl space gmbH CH-8157 DielsdorfSwitzerland space Acoustics gmbH CH-8157 DielsdorfSwitzerland Zurich University of Applied sciences 8400 WinterhurSwitzerland genov solutions N-5172 LoddefjordNorway sTM Engineering N-5165 LaksevagNorway John Hopkins University Applied Physics Laboratory MD 20723USA NAsA/goddard space Flight Centre MD 20771USA Center for space Physics Boston UniversityBostonMA 02215USA Department of Theoretical Physics and Astrophysics Masaryk University60177 BrnoCzech Republic Institute of Physics E¨otvo¨s Lor´and University1053 BudapestHungary Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100045China Centro de Astrobiologia(CAB) CSIC-INTAMadridSpain

The soft X-ray Imager(sXI)is part of the scientific payload of the solar wind Magnetosphere Ionosphere Link Explorer(sMILE)*** is a joint science mission between the European space Agency(EsA)and the Chinese Academy of sciences(CAs)and is due for launch in *** is a compact X-ray telescope with a wide field-of-view(FOV)capable of encompassing large portions of Earth’s magnetosphere from the vantage point of the sMILE *** is sensitive to the soft X-rays produced by the solar Wind Charge eXchange(sWCX)process produced when heavy ions of solar wind origin interact with neutral particles in Earth’s *** provides a mechanism for boundary detection within the magnetosphere,such as the position of Earth’s magnetopause,because the solar wind heavy ions have a very low density in regions of closed magnetic field *** sensitivity of the sXI is such that it can potentially track movements of the magnetopause on timescales of a few minutes and the orbit of sMILE will enable such movements to be tracked for segments lasting many *** is led by the University of Leicester in the United Kingdom(UK)with collaborating organisations on hardware,software and science support within the UK,Europe,China and the United states.

关键词： soft X-ray Imaging micropore optics large area CCD

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MXenes for Bioinspired soft Actuators:Advancements in Angle-Independent structural Colors and Beyond

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Nano-Micro Letters 2024年第8期16卷 18-34页

作者： siavash Iravani Rajender s.Varma Independent Researcher W Nazar STBoostan AveIsfahanIran Centre of Excellence for Research in sustainable Chemistry Department of ChemistryFederal University of São CarlosSão CarlosSP 13565‑905Brazil

soft actuators have garnered substantial attention in current years in view of their potential appliances in diverse domains like robotics,biomedical devices,and biomimetic *** actuators mimic the natural movements of living organisms,aiming to attain enhanced flexibility,adaptability,and *** the other hand,angle-independent structural color has been achieved through innovative design strategies and engineering *** carefully controlling the size,shape,and arrangement of nanostructures,researchers have been able to create materials exhibiting consistent colors regardless of the viewing *** promising class of materials that holds great potential for bioinspired soft actuators is MXenes in view of their exceptional mechanical,electrical,and optical *** integration of MXenes for bioinspired soft actuators with angle-independent structural color offers exciting *** material compatibility issues,improving color reproducibility,scalability,durability,power supply efficiency,and cost-effectiveness will play vital roles in advancing these *** perspective appraises the development of bioinspired MXene-centered soft actuators with angleindependent structural color in soft robotics.

关键词： MXenes MXene-based composites Bioinspired soft robotics Angle-independent structural color

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Neutrophils in the tumor microenvironment-when a company becomes a crowd

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Cellular & Molecular Immunology 2024年第4期21卷 313-314页

作者： Zvi g.Fridlender Zvi granot Faculty of Medicine Hebrew University of JerusalemJerusalemIsrael Institute of Pulmonary Medicine Hadassah-Hebrew University Medical Center91120 JerusalemIsrael Department of Developmental Biology and Cancer Research Institute for Medical Research Israel CanadaFaculty of MedicineHebrew University91120 JerusalemIsrael

Traditionally,neutrophils are perceived as terminally differentiated cells with defined functions and limited *** is commonly believed that circulating,marginating and tissue-infiltrating neutrophils belong to the same homogeneous population and are capable of switching between these *** research has stagnated since the early 1980s,maintaining a narrow and simplistic view of their capabilities.

关键词： narrow infiltrating differentiated

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Twenty years of population dynamics in European beech-oak forest at their rear range margin anticipate changes in its structure and composition

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Forest Ecosystems 2024年第3期11卷 358-370页

作者： álvaro Rubio-Cuadrado Iciar Alberdi Isabel Canellas Fernando Montes Jesús Rodríguez-Calcerrada Rosana López guillermo g.gordaliza María Valbuena-Carabana Nikos Nanos Ramón Perea Luis gil Departamento de dinamica y gestion forestal Instituto de Ciencias Forestales(ICIFOR-INIA)CSICCtra.La Coruna km 7.528040MadridSpain Departamento de sistemas y Recursos Naturales Escuela Tecnica Superior de Ingeniería de MontesForestal y del Medio NaturalUniversidad Politecnica de Madrid.Ciudad Universitaria s/n28040MadridSpain school of Forestry and Natural Environment Aristotle University of ThessalonikiUniversity Campus54124ThessalonikiGreece

There is an increasing interest in restoring degraded forests,which occupy half of the forest *** the forms of restoration,passive restoration,which involves the elimination of degrading factors and the free evolution of natural dynamics by applying minimal or no management,is gaining *** dynamics is difficult to predict due to the influence of multiple interacting factors such as climatic and edaphic conditions,composition and abundance of species,and the successional character of these ***,we study the natural dynamics of a mixed forest located in central spain,which maintained an open forest structure,due to intensive use,until grazing and cutting were banned in the *** most frequent woody species in this forest are Fagus sylvatica,Quercus petraea,Quercus pyrenaica,Ilex aquifolium,sorbus aucuparia,sorbus aria and Prunus avium,with contrasting shade and drought *** species are common in temperate European deciduous forest and are found here near their southern distribution limit,except for *** order to analyze forest dynamics and composition,three inventories were carried out in 1994,2005 and *** results show that,despite the Mediterranean influence,the natural dynamics of this forest has been mainly determined by different levels of shade *** the abandonment of grazing and cutting,*** expanded rapidly due to its lower shade tolerance,whereas after canopy closure and forest densification,shade-tolerant species gained ground,particularly ***,despite its lower drought and late-frost *** the current dynamics continue,*** will overtake the rest of the species,which will be relegated to sites with shallow soils and steep ***,all the multi-centennial beech trees,which are undergoing a rapid mortality and decline process,will disappear.

关键词： Forest succession secondary forest Woodland Mixed forest Competition Recruitment

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Microstructure， electrochemical， wear and corrosive wear performance of laser-based powder bed fusion(lpbf) and wrought biomedical Ti-6Al-4V alloys

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Transactions of Nonferrous Metals society of China 2024年

作者： A.g.Lekatou B.V.Efremenko V.Haoui V.g.Efremenko s.Emmanouilidou V.I.Zurnadzhy I.Petryshynets Yu.g.Chabak I.I.sili Laboratory of Applied Metallurgy， Department of Materials science and Engineering， school of Engineering， University of Ioannina Institute of Materials science and Computing， University Research Center of Ioannina (URCI) Pryazovskyi state Technical University， Department of Physics Institute of Materials Research of slovak Academy of sciences

Wrought and laser powder bed fusion （LPBF） Ti-6Al-4V specimens were comparatively evaluated， with the objective to determine LPBF Ti-6-4’s suitability for biomedical applications. Testing included nanoindentation， cyclic polarization in simulated body fluid （sBF， 37 ℃ ）， and dry and sBF “Ball-on-Plate” sliding. Wrought Ti-6-4 exhibited a lamellar （α+β） microstructure， whereas LPBF displayed a fine-grained α'-martensite microstructure. LPBF Ti-6-4 demonstrated ～3% higher indentation modulus and ～32% higher hardness， while wrought Ti-6-4 showed ～8% higher plasticity. Both alloys exhibited low corrosion rates (10–5mA/cm2order) and true passivity (10–4mA/cm2order). No localized corrosion was observed in either alloy， except for occasional metastable pitting in the LPBF alloy. However， LPBF Ti-6-4 presented higher corrosion rate and passive current， ascribed to its martensitic structure. During dry sliding， LPBF Ti-6-4 exhibited ～14% lower volume loss compared to wrought Ti-6-4. sliding in sBF increased volume losses for both alloys， with wear resistances nearly equalized， as the advantage of LPBF Ti-6-4 decreased due to more intensive wear-accelerated corrosion induced by the stressed martensite. Overall， the results demonstrate the suitability of LPBF Ti-6Al-4V for biomedical uses.

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Tensor force impact on shell evolution in neutron-rich si and Ni isotopes

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Chinese Physics C 2024年第4期48卷 95-106页

作者： s.V.sidorov A.s.Kornilova T.Yu.Tretyakova Faculty of Physics Lomonosov Moscow State UniversityMoscow 119991Russia skobeltsyn Institute of Nuclear Physics Lomonosov Moscow State UniversityMoscow 119991Russia

The influence of the tensor interaction of nucleons on the characteristics of neutron-rich silicon and nickel isotopes was studied in this *** forces are considered within the framework of the Hartree-Fock approach with the skyrme *** addition of a tensor component of interaction is shown to improve the description of the splittings between different single-particle states and decrease nucleon-nucleon pairing correlations in silicon and nickel *** attention was directed toward the role of isovector tensor forces relevant to the interaction of like nucleons.

关键词： nuclear shell model tensor interaction silicon isotopes nickel isotopes

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The emerging role of exercise as a cancer treatment

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Journal of sport and Health science 2024年第4期13卷 443-444页

作者： Kerry s.Courneya Faculty of Kinesiology Sportand RecreationCollege of Health SciencesUniversity of AlbertaEdmontonAlbertaT6G 2H9Canada

Over the past few decades,exercise oncology has emerged as an important subfield within exercise *** that time,substantial progress has been made in understanding the role of exercise in people newly diagnosed with ca... 详细信息

关键词： cancer treatment exercise

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