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机遇与挑战:发展中国家如何准备下一回合农产品贸易谈判

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农业经济问题 1999年第3期20卷 60-63页

作者： j.n.格林菲尔德韩一军联合国粮农组织商品贸易局

一、积极准备农业谈判的原因众所周知，农业方面进一步的谈判将于１９９９年开始，乌拉圭回合农业协议第２０条款已指明了谈判的方向。促使各个国家对参加农业谈判感兴趣主要有以下两方面原因：（一）主要的法律原因农业协议中的某些条... 详细信息

一、积极准备农业谈判的原因众所周知，农业方面进一步的谈判将于１９９９年开始，乌拉圭回合农业协议第２０条款已指明了谈判的方向。促使各个国家对参加农业谈判感兴趣主要有以下两方面原因：（一）主要的法律原因农业协议中的某些条款将需要分类谈判是主要的法律原因。...

关键词：发展中国家农产品贸易农业谈判国际贸易

Characterization of bright betatron radiation generated by direct laser acceleration of electrons in plasma of near critical density

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Matter and Radiation at Extremes 2024年第2期9卷 26-35页

作者： j.Cikhardt M.Gyrdymov S.Zähter P.Tavana M.M.Günther n.Bukharskii n.Borisenko j.jacoby X.F.Shen A.Pukhov n.E.Andreev O.n.Rosmej Faculty of Electrical Engineering Czech Technical University in Prague16627 Prague 6Czech Republic Goethe University FrankfurtMax-von-Laue-Straße 160438 Frankfurt am MainGermany GSI Helmholtzzentrum für Schwerionenforschung GmbH Planckstraße 164291 DarmstadtGermany Focused Energy GmbH Im Tiefen See 4564293 DarmstadtGermany national Research nuclear University MEPhI Kashirskoe shosse 31115409 MoscowRussian Federation Lebedev Physical Institute RAS Leninskiy Prospekt 53119991 MoscowRussian Federation Heinrich-Heine-University Düsseldorf Universitätsstrasse 1DüsseldorfGermany joint Institute for High Temperatures RASIzhorskaya st.13Bldg.2125412 MoscowRussian Federation Moscow Institute of Physics and Technology Institutskiy Pereulok 9141700 DolgoprudnyRussia

Directed x-rays produced in the interaction of sub-picosecond laser pulses of moderate relativistic intensity with plasma of near-critical density are investigated. Synchrotron-like (betatron) radiation occurs in the process of direct laser acceleration (DLA) of electrons in a relativisticlaser channel when the electrons undergo transverse betatron oscillations in self-generated quasi-static electric and magnetic fields. In anexperiment at the PHELIX laser system, high-current directed beams of DLA electrons with a mean energy ten times higher than the ponderomotive potential and maximum energy up to 100 MeV were measured at 10^(19) W/cm^(2)laser intensity. The spectrum of directed x-raysin the range of 5–60 keV was evaluated using two sets of Ross filters placed at 0°and 10°to the laser pulse propagation axis. The differential x-ray absorption method allowed for absolute measurements of the angular-dependent photon fluence. We report 10^(13) photons/sr withenergies >5 keV measured at 0°to the laser axis and a brilliance of 10^(21) photons s^(−1) mm^(−2) mrad−2(0.1%BW)−1. The angular distributionof the emission has an FWHM of 14°–16°. Thanks to the ultra-high photon fluence, point-like radiation source, and ultra-short emissiontime, DLA-based keV backlighters are promising for various applications in high-energy-density research with kilojoule petawatt-class laserfacilities.

关键词： laser acceleration critical

The impact of maternal immune activation on the morphology and electrophysiological properties of postnatally-born neurons in the offspring

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neural Regeneration Research 2024年第2期19卷 399-400页

作者： Emilio j.Galván Angelica Zepeda Departamento de Farmacobiología CINVESTAV Unidad Sur CdMxMéxico、Centro de Investigaciones sobre el EnvejecimientoCIE-CinvestavCdMxMéxico Departamento de Medicina Genómica y Toxicología Ambiental Instituto de Investigaciones BiomédicasUniversidad Nacional Autónoma de MéxicoUNAMCdMxMéxico

Pregnancy comes with a combination of physical changes and physiological immunosuppression that increases the susceptibility of women to pathogens and in turn,rises the prevalence of infectious diseases.

关键词： prevalence activation impact

Wettability,reactivity,and interface structure in Mg/ni system

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journal of Magnesium and Alloys 2024年第2期12卷 659-672页

作者： S.Terlicka n.Sobczak Ł.Maj P.Darłak j.j.Sobczak Institute of Metallurgy and Materials Science Polish Academy of Sciences25 Reymonta Str.KrakowPoland Faculty of Foundry Engineering AGH University23 Reymonta Str.KrakowPoland

The sessile drop method was applied to the experimental investigation of the wetting and spreading behaviors of liquid Mg drops on pure ni *** comparison,the experiments were performed in two variants:(1)using the Capillary Purification(CP)procedure,which allows the non-contact heating and squeezing of a pure oxide-free Mg drop;(2)by classical Contact Heating(CH)*** high-temperature tests were performed under isothermal conditions(CP:760℃for 30 s;CH:715℃for 300 s)using Ar+5 wt%H_(2) *** the sessile drop tests,images of the Mg/ni couples were recorded by CCD cameras(57 fps),which were then applied to calculate the contact angles of metal/substrate *** and transmission electron microscopy analyses,both coupled with energy-dispersive X-ray spectroscopy,were used for detailed structural characterization of the solidified *** was found that an oxide-free Mg drop obtained by the CP procedure showed a wetting phenomenon on the ni substrate(an average contact angleθnng and good wetting over the ni substrate(θ_((CP))~20°in 5 s)to form a final contact angle ofθ_(f(CP))~18°.In contrast,a different wetting behavior was observed for the CH procedure,where the unavoidable primary oxide film on the Mg surface blocked the spreading of liquid Mg showing apparently non-wetting behavior after 300 s contact at the test ***,in both cases,the deep craters formed in the ni substrates under the Mg drops and significant change in the structure of initially pure Mg drops to Mg-ni alloys suggest a strong dissolution of ni in liquid Mg and apparent values of the final contact angles measured for the Mg/ni system.

关键词： Magnesium-based alloys Sessile drop tests Capillary purification procedure Wettability Reactivity Contact angle

A hydrodynamic modelling of wave-activated bodies for wavelet marine regions

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Clean Energy 2024年第2期8卷 35-47页

作者： j.S.Peh Mohammed W.Muhieldeen n.H.Shuaib Mechanical Engineering Department Faculty of EngineeringTechnology&Built EnvironmentUCSI UniversityKuala Lumpur56000Malaysia MTC Engineer Sdn.Bhd Shah AlamSelangorMalaysia

Recently,most wave energy research has targeted sea areas with high power density under extreme wave conditions for *** trend often leads to higher energy costs for wave power ***,many marine areas with low power density,characterized by wavelet conditions and less destructive forces than extreme wave conditions,remain ***,this study aimed to propose a wave-activated body model for sea regions with wavelet *** wave-activated body design process encompassed site selection,parameter determination,geometry design,comparison and performance evaluation using the AnSYS®AQWA *** results indicated that the proposed device achieved the desired heave motion,with an amplitude range of 1.2 to-2.5 m,validating its potential for deployment in marine regions with wavelet ***,while the proposed design is optimized for wavelet conditions,it was found to have potential limitations in extreme wave *** observation emphasizes the challenge of formulating a generalized design suitable for both ***,it is pivotal for wave-activated body designs to be customized based on the specific ocean conditions they target,underscoring the need for specialized designs of wave energy converters that consider the unique wave characteristics of their deployment sites.

关键词： wave energy converter South China sea renewable and sustainable energy wavelet AnSYS AQWA hydrodynamic wave-activated bodies

Unmixing detrital zircon U-Pb ages reveals tectonic and climatic depositional influences on the Carboniferous Ansilta Formation,Calingasta-Uspallata Basin,Western Argentina

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Geoscience Frontiers 2024年第4期15卷 61-77页

作者： j.R.Malone j.E.Malone j.L.Isbell D.H.Malone j.P.Craddock K.n.Pauls Department of Geological Sciences Jackson School of GeosciencesUniversity of Texas at AustinAustinTX 78712USA Iowa Geological Survey University of IowaIowa CityIA 52240USA Department of Geosciences University of Wisconsin-MilwaukeeMilwaukeeWI 53211USA Department of Geography Geology and the EnvironmentIllinois State UniversityNormalIL 61790-4400USA

The Late Paleozoic Ice Age(LPIA)was a principal control of sedimentation across Gondwana from the late Devonian through early *** assess the hypothesis that glacial to interglacial transitions in western Argentina were the primary control influencing sediment routing patterns among the various Carboniferous-Permian basins in western *** Carboniferous Ansilta Formation consists of glaciomarine,nearshore,and fluvial systems deposited during the LPIA along the eastern margin of the Calingasta-Uspallata Basin in *** lower,glacially influenced succession of the Ansilta Formation records at least five glacial advances;the upper succession of consists of progradational shallow marine,deltaic,and fluvial *** combine 1225 new U-Pb zircon ages from six samples of the Carboniferous Ansilta Formation in the Calingasta-Uspallata Basin with 5864 U-Pb ages from 147 pub-lished samples in the detrital Pymix forward mixture model to characterize provenance *** the glacially influenced lower Ansilta Formation,sediment was derived locally from the Protoprecordillera,which was a prominent highland with alpine glaciers flowing west and east into the Calingasta-Uspallata and Paganzo basins,***,there was little or no connection between these two basins during Serpukhovian-Bashkirian *** fluvial/deltaic upper Ansilta had distal sediment sources in the Sierras ***,our results support the collapse of the Protoprecordillera topographic barrier,enabling drainage patterns connecting the Paganzo and Calingasta-Uspallata basins by late Pennsylvanian-early Permian time.

关键词： Late Paleozoic Ice Age Argentina Calingasta-Uspallata Basin Ansilta Formation Detrital zircon provenance

Mucopolysaccharidosis typeⅢB:a current review and exploration of the AAV therapy landscape

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neural Regeneration Research 2024年第2期19卷 355-359页

作者： Courtney j.Rouse Victoria n.j.n.en Coy D.Heldermon Lacerta Therapeutics AlachuaFLUSA University of Florida College of Medicine GainesvilleFLUSA

Mucopolysaccharidoses typeⅢB is a rare genetic disorder caused by mutations in the gene that encodes for *** results in the aggregation of heparan sulfate polysaccharides within cell lysosomes that leads to progressive and severe debilitating neurological *** treatment options are expensive,limited,and presently there are no approved cures for mucopolysaccharidoses typeⅢ***-associated virus gene therapy has significantly advanced the field forward,allowing researchers to successfully design,enhance,and improve potential *** group recently published an effective treatment using a codon-optimized triple mutant adeno-associated virus 8 vector that restores n-acetyl-alpha-glucosaminidase levels,auditory function,and lifespan in the murine model for mucopolysaccharidoses typeⅢB to that seen in healthy ***,we review the current state of the field in relation to the capsid landscape,adeno-associated virus gene therapy and its successes and challenges in the clinic,and how novel adenoassociated virus capsid designs have evolved research in the mucopolysaccharidoses typeⅢB field.

关键词： adeno-associated virus central nervous system gene therapy heparan sulfate immune response mucopolysaccharidoses type IIIB n-acetyl-alpha-glucosaminidase newborn screening

A multi-shot target wheel assembly for high-repetition-rate, laser-driven proton acceleration

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High Power Laser Science and Engineering 2024年第2期12卷 87-94页

作者： j.Penas A.Bembibre D.Cortina-Gil L.Martin A.Reija C.Ruiz M.Seimetz A.Alejo j.Benlliure Instituto Galego de Fisica de Altas Enerxias Universidade de Santiago de CompostelaSantiago de CompostelaSpain Laboratorio Laser de Aceleracion y Aplicaciones RIAIDTUniversidade de Santiago de CompostelaSantiago de CompostelaSpain Instituto Universitario de Física Fundamental y Matematicas y Dpto.de Didactica de la Matematica y de las Ciencias Experimentales Universidad de SalamancaSalamancaSpain Instituto de Instrumentación para Imagen Molecular(I3M) CSIC-Universitat Politecnica de ValenciaValenciaSpain

A multi-shot target assembly and automatic alignment procedure for laser–plasma proton acceleration at high repetition rate are *** assembly is based on a multi-target rotating wheel capable of hosting more than 5000 targets,mounted on a 3D motorized stage to allow rapid replenishment and alignment of the target material between laser *** automatic alignment procedure consists of a detailed mapping of the impact positions at the target surface prior to the irradiation that ensures stable operation of the target,which alongside the purpose-built design of the target wheel,enables operation at rates up to 10 *** and continuous laser-driven proton acceleration at 10 Hz is demonstrated,with observed cut-off energy stability about 15%.

关键词： high repetition rate laser-plasma acceleration multi-shot operation proton source target assembly

Evaluation of corneal parameter changes under different accommodative stimuli with Scheimpflug imaging-based tomography

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国际眼科杂志 2024年第9期24卷 1357-1366页

作者： Farid j Bedrán-García David P Piñero Department of Optics Pharmacology and AnatomyUniversity of AlicanteAlicante 03690Spain

AIM:To evaluate the reliability of measurements of corneal changes with accommodation in healthy eyes using a Scheimpflug imaging-based system and how these measurements distribute in the normal ***:Prospective,non-randomized,comparative study including 27 healthy subjects(54 eyes),including emmetropia(13 eyes),myopia(17 eyes),hyperopia(4 eyes)and astigmatism(20 eyes)*** all cases,a complete eye examination was performed,including the analysis of corneal changes with different accommodative stimuli(+2.00,0.00 and-3.00 D)using the Pentacam AXL *** investigation was structured in 2 phases:repeatability analysis and characterization of accommodation-related corneal changes in healthy ***:In the repeatability analysis,the index of height asymmetry(IHA)showed the greatest variability with the three accommodative stimuli,being the results for the rest of parameters *** group of emmetropes showed significant differences with accommodative changes in the position of maximum keratometry(Kmax;Pn the astigmatism group,significant changes were not only observed in the position of Kmax,but also in minimum corneal thickness(MCT),corneal spherical aberration,and total and low order aberration root mean square(all Pnificant difference was found in the displacement of the X position of Kmax with+2.00 D and-3.00 D in the myopia group(P=0.033)as well as in changes with+2.00 D and-3.00 D in the magnitude of the position vector of Kmax in the emmetropia group(Pno significant changes were found between accommodative stimuli in the displacement of coordinates of MCT(P≥0.109).COnCLUSIOn:The position of Kmax and MCT in healthy corneas can change significantly when presenting different accommodative stimuli using the accommodation mode of the Pentacam system,with different trends in these accommodation-related corneal changes between refractive ***,the consistency of the measurement

关键词： corneal biomechanics keratometry corneal thickness pachymetry corneal aberrations Pentacam accommodation