The visual system of teleost fish grows continuously,which is a useful model for studying regeneration of the central nervous system.Glial cells are key for this process,but their contribution is still not well define...The visual system of teleost fish grows continuously,which is a useful model for studying regeneration of the central nervous system.Glial cells are key for this process,but their contribution is still not well defined.We followed oligodendrocytes in the visual system of adult zebrafish during regeneration of the optic nerve at 6,24,and 72 hours post-lesion and at 7 and 14 days post-lesion via the sox10:tagRFP transgenic line and confocal microscopy.To understand the changes that these oligodendrocytes undergo during regeneration,we used Sox2 immunohistochemistry,a stem cell marker involved in oligodendrocyte differentiation.We also used the Click-iT™ Plus TUNEL assay to study cell death and a BrdU assay to determine cell proliferation.Before optic nerve crush,sox10:tagRFP oligodendrocytes are located in the retina,in the optic nerve head,and through all the entire optic nerve.Sox2-positive cells are present in the peripheral germinal zone,the mature retina,and the optic nerve.After optic nerve crush,sox10:tagRFP cells disappeared from the optic nerve crush zone,suggesting that they died,although they were not TUNEL positive.Concomitantly,the number of Sox2-positive cells increased around the crushed area,the optic nerve head,and the retina.Then,between 24 hours post-lesion and 14 days post-lesion,double sox10:tagRFP/Sox2-positive cells were detected in the retina,optic nerve head,and whole optic nerve,together with a proliferation response at 72 hours post-lesion.Our results confirm that a degenerating process may occur prior to regeneration.First,sox10:tagRFP oligodendrocytes that surround the degenerated axons stop wrapping them,change their“myelinating oligodendrocyte”morphology to a“nonmyelinating oligodendrocyte”morphology,and die.Then,residual oligodendrocyte progenitor cells in the optic nerve and retina proliferate and differentiate for the purpose of remyelination.As new axons arise from the surviving retinal ganglion cells,new sox10:tagRFP oligodendrocytes arise from residual oligodendrocyte progenitor cells to guide,nourish and myelinate them.Thus,oligodendrocytes play an active role in zebrafish axon regeneration and remyelination.展开更多
Annual haze in Northern Thailand has become increasingly severe,impacting health and the environment.How-ever,the sources of the haze remain poorly quantified due to limited observational data on aerosol molecular tra...Annual haze in Northern Thailand has become increasingly severe,impacting health and the environment.How-ever,the sources of the haze remain poorly quantified due to limited observational data on aerosol molecular tracers.This study comprehensively investigates chemical composition of PM_(2.5),including both inorganic and organic compounds throughout haze and post-haze periods in 2019 at a rural site of Northern Thailand.Average PM_(2.5) concentrations during haze and post-haze period were 87±36 and 21±11μg/m^(3),respectively.Organic matter was the dominant contributor in PM_(2.5) mass,followed by water soluble inorganic ions and mineral dust.Molecular markers,including levoglucosan,dehydroabietic acid,and 4-nitrocatechol,and ions(Cl^(-),and K^(+)),were used to characterize low haze(PM_(2.5)<100μg/m^(3))and episodic haze(PM_(2.5)>100μg/m^(3)).Low haze is associated with local aerosols from agricultural waste burning,while episodic haze is linked to aged aerosols from mixed agricultural waste,softwood,and hardwood burning.Source apportionment incorporating these molecular markers in receptor modelling(Positive matrix factorization),identified three distinct biomass burning sources:mixed,local,and aged biomass burnings,contributing 31,19 and 13%of PM_(2.5) during haze period.During post-haze period,contributions shifted,with local biomass burning(32%)comparable to secondary sulfate(34%)and mixed dust and traffic sources(26%).These findings demonstrate that both regional and local sources con-tribute to severe haze,highlighting the need for integrated policies for cross-border cooperation as well as stricter regulations to reduce biomass burning in Northern Thailand and Southeast Asia.展开更多
Atomically ordered precious intermetallic nanoparticles have garnered significant attention for diverse applications due to their well-defined surface atomic arrangements and exceptional electronic and geometric prope...Atomically ordered precious intermetallic nanoparticles have garnered significant attention for diverse applications due to their well-defined surface atomic arrangements and exceptional electronic and geometric properties.However,synthesizing non-precious ordered intermetallics that exhibit high stability under operating conditions remains a formidable challenge,primarily owing to their strong oxyphilicity,highly negative reduction potentials,and low corrosion resistance.In this work,we report a facile yet versatile seed-mediated solid-phase approach for fabricating uniform Ni_(3)Ga_(1) intermetallic nanocubes(NCs)fully encapsulated within N-doped carbon layers(denoted as Ni_(3)Ga_(1)@NC-800).Extensive characterization confirms the formation of a unique core-shell architecture,with atomic-resolution structural analysis and X-ray absorption fine structure measurements unequivocally verifying the atomically ordered Ni_(3)Ga_(1) intermetallic phase.The Ni_(3)Ga_(1)@NC-800 catalyst demonstrates exceptional performance in the 1,4-hydrogenation of α,β-unsaturated carbonyl compounds,exhibiting both remarkable activity and exclusive selectivity while maintaining high stability over multiple reaction cycles without observable performance decay.Combined experimental and theoretical calculations reveal that the strong interatomic p-d orbital hybridization facilitates electron transfer from Ga to Ni atoms,resulting in electron localization on ordered Ni atoms.This electronic configuration positively influences H_(2)activation and optimizes substrate adsorption strength,thereby substantially improving catalytic efficiency.Furthermore,this synthetic strategy proves generalizable,successfully extending to the synthesis of other non-precious ordered Ni_(1)Sn_(1) and Ni_(2)In_(3) intermetallics confined within N-doped carbon matrices.展开更多
Rate coefficients of the gas-phase reactions of Cl atoms with a series of fluorinated diketones(FDKs):CF_(3)C(O)CH_(2)C(O)CH_(3)(TFP),CF_(3)C(O)CH_(2)C(O)CH_(2)CH_(3)(TFH)and CF_(3)C(O)CH_(2)C(O)CH(CH_(3))2(TFMH),have...Rate coefficients of the gas-phase reactions of Cl atoms with a series of fluorinated diketones(FDKs):CF_(3)C(O)CH_(2)C(O)CH_(3)(TFP),CF_(3)C(O)CH_(2)C(O)CH_(2)CH_(3)(TFH)and CF_(3)C(O)CH_(2)C(O)CH(CH_(3))2(TFMH),have been measured at(298±2)K and under atmospheric pressure.The experiments were performed using the relative-rate method with a GC-FID detection system.From different determinations and references used,the following rate coefficients were obtained(in cm3/(molecule·sec)):k_(4)(TFP+Cl)=(1.75±0.21)×10^(−10),k_(5)(TFH+Cl)=(2.05±0.23)×10^(−10),k_(6)(TFMH+Cl)=(2.71±0.34)×10^(−10).Reactivity trends of FDKs were discussed and Free Energy Relationships analysis was developed.The expression lgkOH=1.68 lgkCl+5.71 was obtained for the reactivity of the studied FDKs together with similar unsaturated VOCs with Cl and OH radicals Additionally,acetic acid(CH_(3)C(O)OH)and trifluoroacetic acid(CF_(3)C(O)OH)were positively identified and quantified as degradation products using in situ FTIR spectroscopy.According to the identified products,atmospheric chemical mechanisms were proposed.The atmospheric implications of the studied reactions were assessed by the estimation of the tropospheric lifetimes of TFP,TFH,and TFMH concerning their reaction with Cl atoms to be 48,41,and 31 hours,respectively.The relatively short residence in the atmosphere of the fluorocarbons studied will have a local/regional impact with restricted transport.Global warming potential(GWP(20 yr))calculated for the studied fluoro diketones were 0.014,0.003 and 0.001 for TFP,TFH and TFMH,respectively with a negligible contribution to the greenhouse effect.展开更多
A super-radiant terahertz free-electron laser(THz-FEL)light source was developed for the first time in Thailand and Southeast Asia at the PBP-CMU Electron Linac Laboratory(PCELL)of Chiang Mai University.This radiation...A super-radiant terahertz free-electron laser(THz-FEL)light source was developed for the first time in Thailand and Southeast Asia at the PBP-CMU Electron Linac Laboratory(PCELL)of Chiang Mai University.This radiation source requires relatively ultrashort electron bunches to produce intense coherent THz pulses.Three electron bunch compression processes are utilized in the PCELL accelerator system comprising pre-bunch compression in an alpha magnet,velocity bunching in a radio-frequency(RF)linear accelerator(linac),and magnetic bunch compression in a 180°acromat system.Electron bunch compression in the magnetic compressor system poses considerable challenges,which are addressed through the use of three quadrupole doublets.The strengths of the quadrupole fields significantly influence the rotation of the beam line longitudinal phase space distribution along the bunch compressor.Start-to-end beam dynamics simulations using the ASTRA code were performed to optimize the electron beam properties for generating super-radiant THz-FEL radiation.The operational parameters considered in the simulations comprise the alpha magnet gradient,linac RF phase,and quadrupole field strengths.The optimization results show that 10-16MeV femtosecond electron bunches with a low energy spread(~0.2%),small normalized emittance(~15πmm·mrad),and high peak current(165-247A)can be produced by the PCELL accelerator system at the optimal parameters.A THz-FEL with sub-microjoule pulse energies can thus be obtained at the optimized electron beam parameters.The physical and conceptual design of the THz-FEL beamline were completed based on the beam dynamics simulation results.The construction and installation of this beamline are currently underway and expected to be completed by mid-2024.The commissioning of the beamline will then commence.展开更多
The goal of this paper is to show that there are infinitely many number fields K/Q, for which there is no inert prime p ∈ N*, i.e. ∀p ∈ N* a prime number, prime ideal of K such that where: Zk</sub> i...The goal of this paper is to show that there are infinitely many number fields K/Q, for which there is no inert prime p ∈ N*, i.e. ∀p ∈ N* a prime number, prime ideal of K such that where: Zk</sub> is the Dedekind domain of the integer elements of K. To prove such a result, consider for any prime p, the decomposition into a product of prime ideals of Zk</sub>, of the ideal . From this point, we use on the one hand: 1) The well- known property that says: If , then the ideal pZ<sub>k</sub> decomposes into a product of prime ideals of Zk</sub> as following: . (where:;is the irreducible polynomial of θ, and, is its reduction modulo p, which leads to a product of irreducible polynomials in Fp[X]). It is clear that because if is reducible in Fp[X], then consequently p is not inert. Now, we prove the existence of such p, by proving explicit such p as follows. So we use on the other hand: 2) this property that we prove, and which is: If , is an irreducible normalized integer polynomial, whose splitting field is , then for any prime number p ∈ N: is always a reducible polynomial. 3) Consequently, and this closes our proof: let’s consider the set (whose cardinality is infinite) of monogenic biquadratic number fields: . Then each f<sub>θ</sub>(X) checks the above properties, this means that for family M, all its fields, do not admit any inert prime numbers p ∈ N. 2020-Mathematics Subject Classification (MSC2020) 11A41 - 11A51 - 11D25 - 11R04 - 11R09 - 11R11 - 11R16 - 11R32 - 11T06 - 12E05 - 12F05 -12F10 -13A05-13A15 - 13B02 - 13B05 - 13B10 - 13B25 -13F05展开更多
Oligodendrocytes and their cell-intrinsic gene regulatory network:Oligodendrocytes(OLs)are the myelinating glial cells of the vertebrate central nervous system.They are responsible for insulating neuronal axons with a...Oligodendrocytes and their cell-intrinsic gene regulatory network:Oligodendrocytes(OLs)are the myelinating glial cells of the vertebrate central nervous system.They are responsible for insulating neuronal axons with a lipid-rich myelin sheath,which enables the saltatory conduction of action potentials.During development,oligodendrocyte progenitor cells(OPCs)emerge from neural stem cells in the ventricular zone.They then proliferate,increase their number,and migrate to their final destination where they encounter unmyelinated neuronal axons and differentiate in a stepwise fashion into myelinating oligodendrocytes(mOLs)under the influence of environmental stimuli.展开更多
Man-made superheavy elements(SHE)are produced as energetic recoils in complete-fusion reactions and need to be thermalized in a gas-filled chamber for chemical studies.The ever-shorter half-lives and decreasing produc...Man-made superheavy elements(SHE)are produced as energetic recoils in complete-fusion reactions and need to be thermalized in a gas-filled chamber for chemical studies.The ever-shorter half-lives and decreasing production rates of the elements beyond Fl(atomic number Z=114)-the heaviest element chemically studied today-require the development of novel techniques for quantitative thermalization and fast extraction efficiency.The Universal high-density gas stopping Cell(UniCell),currently under construction,was proposed to achieve this.Within this work,we propose an Ion Transfer by Gas Flow(ITGF)device,which serves as a UniCell ejector to interface with a gas chromatography detector array for chemical studies.Detailed parameter optimizations,using gas dynamics and Monte Carlo ion-trajectory simulations,promise fast(within a few ms)and highly efficient(up to 100%)ion extraction across a wide mass range.These ions can then be transmitted quantitatively through the ITGF into the high-pressure environment needed for further chemical studies.展开更多
In the face of the unrelenting challenge posed by earthquakes-a natural hazard of unpredictable nature with a legacy of significant loss of life,destruction of infrastructure,and profound economic and social impacts-t...In the face of the unrelenting challenge posed by earthquakes-a natural hazard of unpredictable nature with a legacy of significant loss of life,destruction of infrastructure,and profound economic and social impacts-the scientific community has pursued advancements in earthquake early warning systems(EEWSs).These systems are vital for pre-emptive actions and decision-making that can save lives and safeguard critical infrastructure.This study proposes and validates a domain-informed deep learning-based EEWS called the hybrid earthquake early warning framework for estimating response spectra(HEWFERS),which represents a significant leap forward in the capabilities to predict ground shaking intensity in real-time,aligning with the United Nations’disaster risk reduction goals.HEWFERS ingeniously integrates a domain-informed variational autoencoder for physics-based latent variable(LV)extraction,a feed-forward neural network for on-site prediction,and Gaussian process regression for spatial prediction.Adopting explainable artificial intelligence-based Shapley explanations further elucidates the predictive mechanisms,ensuring stakeholder-informed decisions.By conducting an extensive analysis of the proposed framework under a large database of approximately 14000 recorded ground motions,this study offers insights into the potential of integrating machine learning with seismology to revolutionize earthquake preparedness and response,thus paving the way for a safer and more resilient future.展开更多
Through the analysis of representative samples of field galaxies,both local(z~0.027)and distant(z~0.7),we explore the barred galaxy fraction and its dependence on stellar mass,color,and morphology,aiming to understand...Through the analysis of representative samples of field galaxies,both local(z~0.027)and distant(z~0.7),we explore the barred galaxy fraction and its dependence on stellar mass,color,and morphology,aiming to understand the evolution of these structural components through cosmic time.To this end,two complementary bar detection techniques were employed:elliptical isophote fitting and two-dimensional Fourier analysis,both applied to deep optical images.The observational samples were drawn from previously established and calibrated catalogs to ensure a homogeneous selection in stellar mass,enabling a robust comparison between local galaxies(z~0.027)and those in the distant Universe(z~0.7).This study systematically applies both isophotal fitting and Fourier decomposition across a wide redshift range,offering a comprehensive view of the evolution of bar incidence as a function of stellar mass and morphology.The results indicate that the fraction of barred galaxies is significantly higher in the local Universe than at earlier epochs,particularly among spiral galaxies.Furthermore,a clear correlation is observed between the presence of bars and stellar mass,especially in the high-mass regime(log(M_*/M☉)>10.5).In distant galaxies,this fraction is lower across all mass ranges,which may be related to more active dynamical processes.Overall,the findings reinforce the idea that stellar bars emerge as a consequence of dynamical cooling and the progressive stabilization of galactic disks,playing a key role in gas transport and the internal structural evolution of galaxies from z~1 to the present day.展开更多
Kinetics of the gas-phase reactions of•OH radicals with a series of fluoroesters were studied for the first time at 298±3 K and atmospheric pressure.Relative rate coefficients were determined by in situ FTIR spec...Kinetics of the gas-phase reactions of•OH radicals with a series of fluoroesters were studied for the first time at 298±3 K and atmospheric pressure.Relative rate coefficients were determined by in situ FTIR spectroscopy in nitrogen and GC-FID in air to monitor the decay of reactants and references.The following coefficient values(in 10^(−12)cm^(3)/(molecule•sec))were obtained for ethyl fluoroacetate(EFA),ethyl 4,4,4-trifluorobutyrate(ETB),and butyl fluoroacetate(BFA),respectively:k_(1)(EFA+OH)=1.15±0.25 by FTIR and 1.34±0.23 by GC-FID;k_(2)(ETB+OH)=1.61±0.36 by FTIR and 2.02±0.30 by GC-FID;k_(3)(BFA+OH)=2.24±0.37 by FTIR.Reactivity trends were developed and correlated with the number of CH_(3)and F substituents in the fluoroester,and structure-activity relationships(SARs)calculations were performed.In addition,the tropospheric lifetimes of EFA,ETB,and BFA upon degradation by OH radicals were calculated to be 9,6,and 5 days,respectively,indicating that these fluorinated compounds could have a possible regional effect from the emission source.Relatively small photochemical ozone creation potentials of 9,7,and 19 were estimated for EFA,ETB,and BFA,respectively.The GlobalWarming Potentials(GWPs)for EFA,ETB,and BFA were calculated for different time horizons.For a 20-year time horizon,the GWPs were 1.393,0.063,and 0.062,respectively.In the case of a 100-year time horizon,the GWPs were 0.379,0.017,and 0.017,and for a 500-year time horizon,the GWPs were 0.108,0.005,and 0.005 for EFA,ETB,and BFA.展开更多
Plants and their interaction partners offer unparalleled views of evolutionary ecology.Nectar larceny,entailing nectar extraction without pollinating,is thought to be an example of a harmful,antagonistic behavior,but ...Plants and their interaction partners offer unparalleled views of evolutionary ecology.Nectar larceny,entailing nectar extraction without pollinating,is thought to be an example of a harmful,antagonistic behavior,but the precise consequences of floral larceny on plant reproductive success remain contentious.We conducted a comprehensive meta-analysis of 153 studies across 120 plant species,using 14 moderators to assess the effects of floral larceny on plant reproductive success and examine the key moderators.We found that floral larceny negatively impacts flower traits,pollinator visitation,pollen deposition,and fruit set,while having a neutral effect on critical female fitness indicators,such as seed set and seed quality,as well as on male fitness.By altering pollinator behavior,floral larceny may reduce geitonogamy,potentially enhancing genetic diversity.Additionally,factors such as pollinator type,plant mating system,and pollen limitation were identified as key moderators of these effects.Our analysis reveals an ultimately neutral effect of floral larceny on plant reproductive success,with potential benefits in certain contexts.These findings suggest that floral larceny plays a complex and multifaceted role within plant-pollinator interactions,facilitating the evolutionary stability and coexistence of floral larcenists and host plants.展开更多
Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)into value-added products has been regarded as an effective way to achieve the goal of carbon neutrality.The intrinsic activity of electrocatalysts,as well as the rea...Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)into value-added products has been regarded as an effective way to achieve the goal of carbon neutrality.The intrinsic activity of electrocatalysts,as well as the reaction microenvironment,play an important role in improving the conversion efficiency of CO_(2).Herein,we report an ionic liquidfunctionalized Au/Pd heterostructure as the electrocatalyst for CO_(2)RR via introducing 1-butyl-1-methylpyrrolidine bis(trifluoromethylsulfonyl)imide([BMPyrr][NTf_(2)])ionic liquid.Au nanoclusters are epitaxially confined on Pd nanosheets in heterostructure,resulting in abundant and well-defined heterointerfaces that work as highly active catalytic sites.Notably,the[BMPyrr][NTf_(2)]achieves charge redistribution at the Au-Pd heterointerfaces,which helps to stabilize*CO_(2)^(˙-)intermediate and further reduce the energy barrier of *COOH formation.Furthermore,the[BMPyrr][NTf_(2)]molecules with high CO_(2)adsorption ability is beneficial to construct a CO_(2)-rich reaction microenvironment at the gas-liquid-solid three-phase interface.The hybrid electrocatalyst exhibits greatly improved CO Faradaic efficiency in a broad potential range and CO partial current density.This work provides a novel strategy for designing robust CO_(2)RR electrocatalysts via ionic liquid-mediated surface modification.展开更多
The sulfur-fumigation process not only induces the chemical transformation of Lycium barbarum(Lb,a widely used traditional Chinese medicine)but also severely influences human health.Given the existing challenges like ...The sulfur-fumigation process not only induces the chemical transformation of Lycium barbarum(Lb,a widely used traditional Chinese medicine)but also severely influences human health.Given the existing challenges like the complex and time-consuming operation,as well as the high technical demands of the current detection methods for sulfur-fumed Lycium barbarum(SF-Lb),this paper employs a simple chemiresistor to carry out discrimination research between Lb and SF-Lb which have significant differences in volatolomics.The sensor is constructed by a conductive metal-organic framework(cMOF)thin film,Cu_(3)(HHTP)_(2),due to its abundant active sites,excellent electron transfer performance as well as the capacity to detect specific groups of volatile organic compounds(VOCs).Consequently,the response values of Cu_(3)(HHTP)_(2)-based sensor to 0.5 g SF-Lb(151.74%)are significantly higher than those to normal Lb(80.07%),identifying SF-Lb simply and rapidly with an accuracy of~100%.Our work investigates volatolomics of SF-Lb and establishes a new rapid discrimination method for sulfur-fumed traditional Chinese herbs.展开更多
Osteoarthritis(OA),a debilitating joint disorder affecting millions worldwide,is characterized by persistent inflammation,oxidative stress,and irreversible cartilage breakdown,yet remains without diseasemodifying ther...Osteoarthritis(OA),a debilitating joint disorder affecting millions worldwide,is characterized by persistent inflammation,oxidative stress,and irreversible cartilage breakdown,yet remains without diseasemodifying therapies.Inspired by natural enzymatic cascades,we developed a bioinspired nanocomposite hydrogel,N,S-doped Mn-Nb(C-CeO),that mimics endogenous antioxidant pathways to reprogram the OA microenvironment.This system combines N,Sdoped Mn-Nb_(2)C MXene nanosheets with CeO_(2)nanozymes within a boronate ester-crosslinked hydrogel,forming an“immuno-redox circuitry”with four synergistic functions:(1)cascade reactive oxygen species(ROS)scavenging via superoxide dismutase-like Mn-Nb_(2)C and catalase-like CeO_(2),amplified by photothermal enhancement under near-infrared irradiation;(2)broad reactive nitrogen species clearance,removing peroxynitrite(ONOO^(-)),nitric oxide(NO),and nitroxyl(NO^(-))to mitigate inflammation;(3)immunomodulation through Mn^(2+)-activated cGAS-STING signaling,which promoted macrophage polarization toward the M2 phenotype,concomitantly reducing the levels of pro-inflammatory cytokines such as interleukin-1 beta(IL-1β)and tumor necrosis factor-alpha(TNF-α);(4)cartilage regeneration via pH/ROS-responsive simvastatin(SIM)release and nanocatalysis,upregulating SRY-box transcription factor 9(SOX9)and Col2a1 while inhibiting matrix metalloproteinase-13(MMP-13)and a disintegrin and metalloproteinase with thrombospondin motifs 5(ADAMTS5).In a murine OA model,the system reduced synovitis by 60%,restored 80% of cartilage thickness,and suppressed osteophyte formation,outperforming singlecomponent treatments.This strategy pioneers a“self-healing cartilage”approach by integrating nanocatalysis with immunoengineering for transformative OA therapy.展开更多
The Chilean Pampean flat slab subduction segment is characterized by the nearly horizontal subduction of the Nazca Plate within the depth range of 100-120 km.Numerous seismic tomography studies have been conducted to ...The Chilean Pampean flat slab subduction segment is characterized by the nearly horizontal subduction of the Nazca Plate within the depth range of 100-120 km.Numerous seismic tomography studies have been conducted to investigate its velocity structure;however,they have used only seismic body wave data or surface wave data.As a result,the existing velocity models in the region may have relatively large uncertainties.In this study,we use body wave arrival times from earthquakes occurring in central Chile between 2014 and 2019,as well as Rayleigh wave phase velocity maps at periods of 5-80 s from ambient noise empirical Green’s functions in Chile.By jointly using body wave arrival times and surface wave dispersion data,we refine the VS model and improve earthquake locations in the central Chile subduction zone.Compared with previous velocity models,our velocity model better reveals an eastward-dipping high-velocity plate representing the subducting Nazca Plate,which is 40-50 km thick and is more consistent with the slab thickness estimated by receiver function imaging and thermal modeling.Overall,the intraslab seismicity distribution spatially correlates well with the slab high-velocity anomalies except along the subduction paths of the CopiapóRidge and Juan Fernández Ridge.Additionally,parallel low-velocity stripes are imaged beneath the subducting plate,which are likely associated with the accumulated melts.The joint inversion velocity model also resolves widespread low-velocity anomalies in the crust beneath the Central Volcanic Zone of the central Andes,likely representing crustal magma chambers for various volcanoes.展开更多
基金supported by the Lanzadera TCUE and C2 program(Universidad de Salamanca)(to ASL)the Spanish National Research Council(CSIC)funded by the Junta de Castilla y León and co-financed by the European Regional Development Fund(ERDF“Europe drives our growth”):Internationalization Project“CL-EI-2021-08-IBFG Unit of Excellence”,Grant(PID2022-138478OA-100)funded by MICIU/AEI/10.13039/501100011033 and,by FEDER,UE(to MGM)+3 种基金Junta de Castilla y León(SA225P23)Gerencia Regional de Salud(2701/A1/2023)(to AV)the Plan Especial Grado Medicina(USAL)(to CPM)a Ramón y Cajal researcher:Grant RYC2021-033684-I funded by MICIU/AEI/10.13039/501100011033 and,by European Union NextGenerationEU/PRTR.
文摘The visual system of teleost fish grows continuously,which is a useful model for studying regeneration of the central nervous system.Glial cells are key for this process,but their contribution is still not well defined.We followed oligodendrocytes in the visual system of adult zebrafish during regeneration of the optic nerve at 6,24,and 72 hours post-lesion and at 7 and 14 days post-lesion via the sox10:tagRFP transgenic line and confocal microscopy.To understand the changes that these oligodendrocytes undergo during regeneration,we used Sox2 immunohistochemistry,a stem cell marker involved in oligodendrocyte differentiation.We also used the Click-iT™ Plus TUNEL assay to study cell death and a BrdU assay to determine cell proliferation.Before optic nerve crush,sox10:tagRFP oligodendrocytes are located in the retina,in the optic nerve head,and through all the entire optic nerve.Sox2-positive cells are present in the peripheral germinal zone,the mature retina,and the optic nerve.After optic nerve crush,sox10:tagRFP cells disappeared from the optic nerve crush zone,suggesting that they died,although they were not TUNEL positive.Concomitantly,the number of Sox2-positive cells increased around the crushed area,the optic nerve head,and the retina.Then,between 24 hours post-lesion and 14 days post-lesion,double sox10:tagRFP/Sox2-positive cells were detected in the retina,optic nerve head,and whole optic nerve,together with a proliferation response at 72 hours post-lesion.Our results confirm that a degenerating process may occur prior to regeneration.First,sox10:tagRFP oligodendrocytes that surround the degenerated axons stop wrapping them,change their“myelinating oligodendrocyte”morphology to a“nonmyelinating oligodendrocyte”morphology,and die.Then,residual oligodendrocyte progenitor cells in the optic nerve and retina proliferate and differentiate for the purpose of remyelination.As new axons arise from the surviving retinal ganglion cells,new sox10:tagRFP oligodendrocytes arise from residual oligodendrocyte progenitor cells to guide,nourish and myelinate them.Thus,oligodendrocytes play an active role in zebrafish axon regeneration and remyelination.
文摘Annual haze in Northern Thailand has become increasingly severe,impacting health and the environment.How-ever,the sources of the haze remain poorly quantified due to limited observational data on aerosol molecular tracers.This study comprehensively investigates chemical composition of PM_(2.5),including both inorganic and organic compounds throughout haze and post-haze periods in 2019 at a rural site of Northern Thailand.Average PM_(2.5) concentrations during haze and post-haze period were 87±36 and 21±11μg/m^(3),respectively.Organic matter was the dominant contributor in PM_(2.5) mass,followed by water soluble inorganic ions and mineral dust.Molecular markers,including levoglucosan,dehydroabietic acid,and 4-nitrocatechol,and ions(Cl^(-),and K^(+)),were used to characterize low haze(PM_(2.5)<100μg/m^(3))and episodic haze(PM_(2.5)>100μg/m^(3)).Low haze is associated with local aerosols from agricultural waste burning,while episodic haze is linked to aged aerosols from mixed agricultural waste,softwood,and hardwood burning.Source apportionment incorporating these molecular markers in receptor modelling(Positive matrix factorization),identified three distinct biomass burning sources:mixed,local,and aged biomass burnings,contributing 31,19 and 13%of PM_(2.5) during haze period.During post-haze period,contributions shifted,with local biomass burning(32%)comparable to secondary sulfate(34%)and mixed dust and traffic sources(26%).These findings demonstrate that both regional and local sources con-tribute to severe haze,highlighting the need for integrated policies for cross-border cooperation as well as stricter regulations to reduce biomass burning in Northern Thailand and Southeast Asia.
基金financially supported by the program of the National Natural Science Foundation of Shandong Province(No.ZR2023ZD23)the Shandong Province Key Research and Development Plan(No.2023CXGC010607).
文摘Atomically ordered precious intermetallic nanoparticles have garnered significant attention for diverse applications due to their well-defined surface atomic arrangements and exceptional electronic and geometric properties.However,synthesizing non-precious ordered intermetallics that exhibit high stability under operating conditions remains a formidable challenge,primarily owing to their strong oxyphilicity,highly negative reduction potentials,and low corrosion resistance.In this work,we report a facile yet versatile seed-mediated solid-phase approach for fabricating uniform Ni_(3)Ga_(1) intermetallic nanocubes(NCs)fully encapsulated within N-doped carbon layers(denoted as Ni_(3)Ga_(1)@NC-800).Extensive characterization confirms the formation of a unique core-shell architecture,with atomic-resolution structural analysis and X-ray absorption fine structure measurements unequivocally verifying the atomically ordered Ni_(3)Ga_(1) intermetallic phase.The Ni_(3)Ga_(1)@NC-800 catalyst demonstrates exceptional performance in the 1,4-hydrogenation of α,β-unsaturated carbonyl compounds,exhibiting both remarkable activity and exclusive selectivity while maintaining high stability over multiple reaction cycles without observable performance decay.Combined experimental and theoretical calculations reveal that the strong interatomic p-d orbital hybridization facilitates electron transfer from Ga to Ni atoms,resulting in electron localization on ordered Ni atoms.This electronic configuration positively influences H_(2)activation and optimizes substrate adsorption strength,thereby substantially improving catalytic efficiency.Furthermore,this synthetic strategy proves generalizable,successfully extending to the synthesis of other non-precious ordered Ni_(1)Sn_(1) and Ni_(2)In_(3) intermetallics confined within N-doped carbon matrices.
文摘Rate coefficients of the gas-phase reactions of Cl atoms with a series of fluorinated diketones(FDKs):CF_(3)C(O)CH_(2)C(O)CH_(3)(TFP),CF_(3)C(O)CH_(2)C(O)CH_(2)CH_(3)(TFH)and CF_(3)C(O)CH_(2)C(O)CH(CH_(3))2(TFMH),have been measured at(298±2)K and under atmospheric pressure.The experiments were performed using the relative-rate method with a GC-FID detection system.From different determinations and references used,the following rate coefficients were obtained(in cm3/(molecule·sec)):k_(4)(TFP+Cl)=(1.75±0.21)×10^(−10),k_(5)(TFH+Cl)=(2.05±0.23)×10^(−10),k_(6)(TFMH+Cl)=(2.71±0.34)×10^(−10).Reactivity trends of FDKs were discussed and Free Energy Relationships analysis was developed.The expression lgkOH=1.68 lgkCl+5.71 was obtained for the reactivity of the studied FDKs together with similar unsaturated VOCs with Cl and OH radicals Additionally,acetic acid(CH_(3)C(O)OH)and trifluoroacetic acid(CF_(3)C(O)OH)were positively identified and quantified as degradation products using in situ FTIR spectroscopy.According to the identified products,atmospheric chemical mechanisms were proposed.The atmospheric implications of the studied reactions were assessed by the estimation of the tropospheric lifetimes of TFP,TFH,and TFMH concerning their reaction with Cl atoms to be 48,41,and 31 hours,respectively.The relatively short residence in the atmosphere of the fluorocarbons studied will have a local/regional impact with restricted transport.Global warming potential(GWP(20 yr))calculated for the studied fluoro diketones were 0.014,0.003 and 0.001 for TFP,TFH and TFMH,respectively with a negligible contribution to the greenhouse effect.
基金support from the NSRF via the Program Management Unit for Human Resources&Institutional Development,Research,and Innovation(No.B05F650022),as well as from Chiang Mai University.
文摘A super-radiant terahertz free-electron laser(THz-FEL)light source was developed for the first time in Thailand and Southeast Asia at the PBP-CMU Electron Linac Laboratory(PCELL)of Chiang Mai University.This radiation source requires relatively ultrashort electron bunches to produce intense coherent THz pulses.Three electron bunch compression processes are utilized in the PCELL accelerator system comprising pre-bunch compression in an alpha magnet,velocity bunching in a radio-frequency(RF)linear accelerator(linac),and magnetic bunch compression in a 180°acromat system.Electron bunch compression in the magnetic compressor system poses considerable challenges,which are addressed through the use of three quadrupole doublets.The strengths of the quadrupole fields significantly influence the rotation of the beam line longitudinal phase space distribution along the bunch compressor.Start-to-end beam dynamics simulations using the ASTRA code were performed to optimize the electron beam properties for generating super-radiant THz-FEL radiation.The operational parameters considered in the simulations comprise the alpha magnet gradient,linac RF phase,and quadrupole field strengths.The optimization results show that 10-16MeV femtosecond electron bunches with a low energy spread(~0.2%),small normalized emittance(~15πmm·mrad),and high peak current(165-247A)can be produced by the PCELL accelerator system at the optimal parameters.A THz-FEL with sub-microjoule pulse energies can thus be obtained at the optimized electron beam parameters.The physical and conceptual design of the THz-FEL beamline were completed based on the beam dynamics simulation results.The construction and installation of this beamline are currently underway and expected to be completed by mid-2024.The commissioning of the beamline will then commence.
文摘The goal of this paper is to show that there are infinitely many number fields K/Q, for which there is no inert prime p ∈ N*, i.e. ∀p ∈ N* a prime number, prime ideal of K such that where: Zk</sub> is the Dedekind domain of the integer elements of K. To prove such a result, consider for any prime p, the decomposition into a product of prime ideals of Zk</sub>, of the ideal . From this point, we use on the one hand: 1) The well- known property that says: If , then the ideal pZ<sub>k</sub> decomposes into a product of prime ideals of Zk</sub> as following: . (where:;is the irreducible polynomial of θ, and, is its reduction modulo p, which leads to a product of irreducible polynomials in Fp[X]). It is clear that because if is reducible in Fp[X], then consequently p is not inert. Now, we prove the existence of such p, by proving explicit such p as follows. So we use on the other hand: 2) this property that we prove, and which is: If , is an irreducible normalized integer polynomial, whose splitting field is , then for any prime number p ∈ N: is always a reducible polynomial. 3) Consequently, and this closes our proof: let’s consider the set (whose cardinality is infinite) of monogenic biquadratic number fields: . Then each f<sub>θ</sub>(X) checks the above properties, this means that for family M, all its fields, do not admit any inert prime numbers p ∈ N. 2020-Mathematics Subject Classification (MSC2020) 11A41 - 11A51 - 11D25 - 11R04 - 11R09 - 11R11 - 11R16 - 11R32 - 11T06 - 12E05 - 12F05 -12F10 -13A05-13A15 - 13B02 - 13B05 - 13B10 - 13B25 -13F05
基金supported by grants from the Deutsche Forschungsgemeinschaft(DFG)to MW.
文摘Oligodendrocytes and their cell-intrinsic gene regulatory network:Oligodendrocytes(OLs)are the myelinating glial cells of the vertebrate central nervous system.They are responsible for insulating neuronal axons with a lipid-rich myelin sheath,which enables the saltatory conduction of action potentials.During development,oligodendrocyte progenitor cells(OPCs)emerge from neural stem cells in the ventricular zone.They then proliferate,increase their number,and migrate to their final destination where they encounter unmyelinated neuronal axons and differentiate in a stepwise fashion into myelinating oligodendrocytes(mOLs)under the influence of environmental stimuli.
基金This work was supported by the German BMBF (No.05P21UMFN2)
文摘Man-made superheavy elements(SHE)are produced as energetic recoils in complete-fusion reactions and need to be thermalized in a gas-filled chamber for chemical studies.The ever-shorter half-lives and decreasing production rates of the elements beyond Fl(atomic number Z=114)-the heaviest element chemically studied today-require the development of novel techniques for quantitative thermalization and fast extraction efficiency.The Universal high-density gas stopping Cell(UniCell),currently under construction,was proposed to achieve this.Within this work,we propose an Ion Transfer by Gas Flow(ITGF)device,which serves as a UniCell ejector to interface with a gas chromatography detector array for chemical studies.Detailed parameter optimizations,using gas dynamics and Monte Carlo ion-trajectory simulations,promise fast(within a few ms)and highly efficient(up to 100%)ion extraction across a wide mass range.These ions can then be transmitted quantitatively through the ITGF into the high-pressure environment needed for further chemical studies.
基金the financial support from the Chilean National Research and Development Agency(Agencia Nacional de Investigación y Desarrollo,ANID)through Fondo Nacional de Desarrollo Científico y Tecnológico(FONDECYT)Regular 1240503Fondo de Valorización de la Investigación(FOVI)230030 projectsthe financial support from the ANID through FONDECYT Reg-ular 1240501.
文摘In the face of the unrelenting challenge posed by earthquakes-a natural hazard of unpredictable nature with a legacy of significant loss of life,destruction of infrastructure,and profound economic and social impacts-the scientific community has pursued advancements in earthquake early warning systems(EEWSs).These systems are vital for pre-emptive actions and decision-making that can save lives and safeguard critical infrastructure.This study proposes and validates a domain-informed deep learning-based EEWS called the hybrid earthquake early warning framework for estimating response spectra(HEWFERS),which represents a significant leap forward in the capabilities to predict ground shaking intensity in real-time,aligning with the United Nations’disaster risk reduction goals.HEWFERS ingeniously integrates a domain-informed variational autoencoder for physics-based latent variable(LV)extraction,a feed-forward neural network for on-site prediction,and Gaussian process regression for spatial prediction.Adopting explainable artificial intelligence-based Shapley explanations further elucidates the predictive mechanisms,ensuring stakeholder-informed decisions.By conducting an extensive analysis of the proposed framework under a large database of approximately 14000 recorded ground motions,this study offers insights into the potential of integrating machine learning with seismology to revolutionize earthquake preparedness and response,thus paving the way for a safer and more resilient future.
基金financial support from the Secretaría Nacional de Ciencia,Tecnologia e Innovacion(SENACYT),through the Departamento de Fortalecimiento a los Posgrados Nacionalesthe coordination of the program"MOVILIDAD DE INVESTIGACION."+3 种基金the financial support provided by PAPIIT projects IN108323 and IN111825 from DGAPA-UNAMsupport from the Agencia Nacional de Investigación y Desarrollo(ANID)through Basal project FB210003FONDECYT Regular projects 1241426 and 123044Millennium Science Initiative Program NCN2024_112。
文摘Through the analysis of representative samples of field galaxies,both local(z~0.027)and distant(z~0.7),we explore the barred galaxy fraction and its dependence on stellar mass,color,and morphology,aiming to understand the evolution of these structural components through cosmic time.To this end,two complementary bar detection techniques were employed:elliptical isophote fitting and two-dimensional Fourier analysis,both applied to deep optical images.The observational samples were drawn from previously established and calibrated catalogs to ensure a homogeneous selection in stellar mass,enabling a robust comparison between local galaxies(z~0.027)and those in the distant Universe(z~0.7).This study systematically applies both isophotal fitting and Fourier decomposition across a wide redshift range,offering a comprehensive view of the evolution of bar incidence as a function of stellar mass and morphology.The results indicate that the fraction of barred galaxies is significantly higher in the local Universe than at earlier epochs,particularly among spiral galaxies.Furthermore,a clear correlation is observed between the presence of bars and stellar mass,especially in the high-mass regime(log(M_*/M☉)>10.5).In distant galaxies,this fraction is lower across all mass ranges,which may be related to more active dynamical processes.Overall,the findings reinforce the idea that stellar bars emerge as a consequence of dynamical cooling and the progressive stabilization of galactic disks,playing a key role in gas transport and the internal structural evolution of galaxies from z~1 to the present day.
文摘Kinetics of the gas-phase reactions of•OH radicals with a series of fluoroesters were studied for the first time at 298±3 K and atmospheric pressure.Relative rate coefficients were determined by in situ FTIR spectroscopy in nitrogen and GC-FID in air to monitor the decay of reactants and references.The following coefficient values(in 10^(−12)cm^(3)/(molecule•sec))were obtained for ethyl fluoroacetate(EFA),ethyl 4,4,4-trifluorobutyrate(ETB),and butyl fluoroacetate(BFA),respectively:k_(1)(EFA+OH)=1.15±0.25 by FTIR and 1.34±0.23 by GC-FID;k_(2)(ETB+OH)=1.61±0.36 by FTIR and 2.02±0.30 by GC-FID;k_(3)(BFA+OH)=2.24±0.37 by FTIR.Reactivity trends were developed and correlated with the number of CH_(3)and F substituents in the fluoroester,and structure-activity relationships(SARs)calculations were performed.In addition,the tropospheric lifetimes of EFA,ETB,and BFA upon degradation by OH radicals were calculated to be 9,6,and 5 days,respectively,indicating that these fluorinated compounds could have a possible regional effect from the emission source.Relatively small photochemical ozone creation potentials of 9,7,and 19 were estimated for EFA,ETB,and BFA,respectively.The GlobalWarming Potentials(GWPs)for EFA,ETB,and BFA were calculated for different time horizons.For a 20-year time horizon,the GWPs were 1.393,0.063,and 0.062,respectively.In the case of a 100-year time horizon,the GWPs were 0.379,0.017,and 0.017,and for a 500-year time horizon,the GWPs were 0.108,0.005,and 0.005 for EFA,ETB,and BFA.
基金support by the National Natural Science Foundation of China(32170241,32160054,and 32470241)supported by the Chinese Academy of Science's PIFI Fellowship Initiative(2024PVC0046).
文摘Plants and their interaction partners offer unparalleled views of evolutionary ecology.Nectar larceny,entailing nectar extraction without pollinating,is thought to be an example of a harmful,antagonistic behavior,but the precise consequences of floral larceny on plant reproductive success remain contentious.We conducted a comprehensive meta-analysis of 153 studies across 120 plant species,using 14 moderators to assess the effects of floral larceny on plant reproductive success and examine the key moderators.We found that floral larceny negatively impacts flower traits,pollinator visitation,pollen deposition,and fruit set,while having a neutral effect on critical female fitness indicators,such as seed set and seed quality,as well as on male fitness.By altering pollinator behavior,floral larceny may reduce geitonogamy,potentially enhancing genetic diversity.Additionally,factors such as pollinator type,plant mating system,and pollen limitation were identified as key moderators of these effects.Our analysis reveals an ultimately neutral effect of floral larceny on plant reproductive success,with potential benefits in certain contexts.These findings suggest that floral larceny plays a complex and multifaceted role within plant-pollinator interactions,facilitating the evolutionary stability and coexistence of floral larcenists and host plants.
基金supported by the National Natural Science Foundation Joint Fund Project(No.U24A2042)Basic Research Foundation of Zhejiang Provincial Universities(No.G23224161033)the National Natural Science Foundation of China(Nos.52072342 and 52377216).
文摘Electrocatalytic CO_(2)reduction reaction(CO_(2)RR)into value-added products has been regarded as an effective way to achieve the goal of carbon neutrality.The intrinsic activity of electrocatalysts,as well as the reaction microenvironment,play an important role in improving the conversion efficiency of CO_(2).Herein,we report an ionic liquidfunctionalized Au/Pd heterostructure as the electrocatalyst for CO_(2)RR via introducing 1-butyl-1-methylpyrrolidine bis(trifluoromethylsulfonyl)imide([BMPyrr][NTf_(2)])ionic liquid.Au nanoclusters are epitaxially confined on Pd nanosheets in heterostructure,resulting in abundant and well-defined heterointerfaces that work as highly active catalytic sites.Notably,the[BMPyrr][NTf_(2)]achieves charge redistribution at the Au-Pd heterointerfaces,which helps to stabilize*CO_(2)^(˙-)intermediate and further reduce the energy barrier of *COOH formation.Furthermore,the[BMPyrr][NTf_(2)]molecules with high CO_(2)adsorption ability is beneficial to construct a CO_(2)-rich reaction microenvironment at the gas-liquid-solid three-phase interface.The hybrid electrocatalyst exhibits greatly improved CO Faradaic efficiency in a broad potential range and CO partial current density.This work provides a novel strategy for designing robust CO_(2)RR electrocatalysts via ionic liquid-mediated surface modification.
基金supported by the National Natural Science Foundation of China(Nos.22205121,22494633,22401281)CAS President's International Fellowship for Visiting Scientists(No.2024VBC0002)+2 种基金the research fund of State Key Laboratory of Mesoscience and Engineering(Nos.MESO-23-A07,MESO-23-T02,MESO-24-A01)First-class Discipline Construction Project(Chemistry)in Higher Education Institutions of Ningxia(Ningxia Normal University)Engineering Research Center of Liupanshan(No.HGZD22-27).
文摘The sulfur-fumigation process not only induces the chemical transformation of Lycium barbarum(Lb,a widely used traditional Chinese medicine)but also severely influences human health.Given the existing challenges like the complex and time-consuming operation,as well as the high technical demands of the current detection methods for sulfur-fumed Lycium barbarum(SF-Lb),this paper employs a simple chemiresistor to carry out discrimination research between Lb and SF-Lb which have significant differences in volatolomics.The sensor is constructed by a conductive metal-organic framework(cMOF)thin film,Cu_(3)(HHTP)_(2),due to its abundant active sites,excellent electron transfer performance as well as the capacity to detect specific groups of volatile organic compounds(VOCs).Consequently,the response values of Cu_(3)(HHTP)_(2)-based sensor to 0.5 g SF-Lb(151.74%)are significantly higher than those to normal Lb(80.07%),identifying SF-Lb simply and rapidly with an accuracy of~100%.Our work investigates volatolomics of SF-Lb and establishes a new rapid discrimination method for sulfur-fumed traditional Chinese herbs.
基金supported by the National Natural Science Foundation of China(Nos.82101647 and 82203446)Natural Science Fund of Zhejiang Province(Nos.LY24H250001,LQN25H060003,and LY23H060011)+2 种基金the Postdoctoral Fellowship Program of CPSF(No.188020-170257701/136)the Regional Innovation and Development Joint Fund of the National Natural Science Foundation of China(No.U22A20282)the Guangdong Basic and Applied Basic Research Foundation(No.2023A1515220225).
文摘Osteoarthritis(OA),a debilitating joint disorder affecting millions worldwide,is characterized by persistent inflammation,oxidative stress,and irreversible cartilage breakdown,yet remains without diseasemodifying therapies.Inspired by natural enzymatic cascades,we developed a bioinspired nanocomposite hydrogel,N,S-doped Mn-Nb(C-CeO),that mimics endogenous antioxidant pathways to reprogram the OA microenvironment.This system combines N,Sdoped Mn-Nb_(2)C MXene nanosheets with CeO_(2)nanozymes within a boronate ester-crosslinked hydrogel,forming an“immuno-redox circuitry”with four synergistic functions:(1)cascade reactive oxygen species(ROS)scavenging via superoxide dismutase-like Mn-Nb_(2)C and catalase-like CeO_(2),amplified by photothermal enhancement under near-infrared irradiation;(2)broad reactive nitrogen species clearance,removing peroxynitrite(ONOO^(-)),nitric oxide(NO),and nitroxyl(NO^(-))to mitigate inflammation;(3)immunomodulation through Mn^(2+)-activated cGAS-STING signaling,which promoted macrophage polarization toward the M2 phenotype,concomitantly reducing the levels of pro-inflammatory cytokines such as interleukin-1 beta(IL-1β)and tumor necrosis factor-alpha(TNF-α);(4)cartilage regeneration via pH/ROS-responsive simvastatin(SIM)release and nanocatalysis,upregulating SRY-box transcription factor 9(SOX9)and Col2a1 while inhibiting matrix metalloproteinase-13(MMP-13)and a disintegrin and metalloproteinase with thrombospondin motifs 5(ADAMTS5).In a murine OA model,the system reduced synovitis by 60%,restored 80% of cartilage thickness,and suppressed osteophyte formation,outperforming singlecomponent treatments.This strategy pioneers a“self-healing cartilage”approach by integrating nanocatalysis with immunoengineering for transformative OA therapy.
基金funded by the National Natural Science Foundation of China under Grant 42230101the National Agency for Research and Development of Chile(ANID)by Projects AFB180004 and AFB220002the ANID Programa de Cooperación Internacional(PCI)Grant PII-180003.
文摘The Chilean Pampean flat slab subduction segment is characterized by the nearly horizontal subduction of the Nazca Plate within the depth range of 100-120 km.Numerous seismic tomography studies have been conducted to investigate its velocity structure;however,they have used only seismic body wave data or surface wave data.As a result,the existing velocity models in the region may have relatively large uncertainties.In this study,we use body wave arrival times from earthquakes occurring in central Chile between 2014 and 2019,as well as Rayleigh wave phase velocity maps at periods of 5-80 s from ambient noise empirical Green’s functions in Chile.By jointly using body wave arrival times and surface wave dispersion data,we refine the VS model and improve earthquake locations in the central Chile subduction zone.Compared with previous velocity models,our velocity model better reveals an eastward-dipping high-velocity plate representing the subducting Nazca Plate,which is 40-50 km thick and is more consistent with the slab thickness estimated by receiver function imaging and thermal modeling.Overall,the intraslab seismicity distribution spatially correlates well with the slab high-velocity anomalies except along the subduction paths of the CopiapóRidge and Juan Fernández Ridge.Additionally,parallel low-velocity stripes are imaged beneath the subducting plate,which are likely associated with the accumulated melts.The joint inversion velocity model also resolves widespread low-velocity anomalies in the crust beneath the Central Volcanic Zone of the central Andes,likely representing crustal magma chambers for various volcanoes.
