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Characterizing and quantifying iron oxides in Chinese loess/paleosols:Implications for pedogenesis

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Characterizing and quantifying iron oxides in Chinese loess/...

中国科学院地质与地球物理研究所2013年度（第13届）学术年会

作者： Pengxiang Hu Qingsong Liu José Torrent vidal barron Chunsheng Jin State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences Departamento de Agronomfa Universidad de CordobaEdificio C4Campus de Rabanales14071 CordobaSpain Division of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of Sciences

To accurately decode the paleoclimatic and paleoenvironmental significance of magnetic properties in Chinese loess/paleosols,neoformation of magnetic iron oxides via pedogenesis as well as the relationship between ferrimagnetic(maghemite and magnetite)and antiferromagnetic minerals(hematite and goethite)of both detrital and pedogenic origins should be well *** resolve this problem, magnetic iron oxides from a contiguous loess-paleosol sequence(lower part of the loess unit L1,paleosol unit S1,and the upper part of L2)at Luochuan,Center of the Chinese Loess Plateau,were well characterized and quantified by using an integrated approach including chemical dissolution,diffuse reflectance spectroscopy and rock magnetism *** showed that these magnetic minerals have distinct coercivity and dissolution behavior,which is highly grain *** specifically, the paleosol is enriched with nano-sized pedogenic hematites with a medium coercivity of～130 mT, which are also preferentially dissolved in a weak reductive *** contrast,the coarse-grained micro-sized detrital hematites with a medium coercivity of～1T are dominant in loess,In addition,these coarse-grained detrital hematites are more stoichiometric than their pedogenic counterparts as evidenced by the higher band position on the diffuse reflectance *** can be well distinguished from hematite by its higher coercivity(4-7T)at low temperature(10K).The consistent dissolution behavior of goethite for both loess and paleosol samples in citrate-bicarbonate-dithionite solution indicates that goethite could be less relevant to the pedogenic *** reductive dissolution of pedogenic maghemite lags the dissolution of pedogenic hematite and fine-grained goethite,which suggests that average grain size of pedogenic maghemite is relatively larger than those of pedogenic hematite and fine-grained *** magnetite is hard to dissolve and～50%of its initial remanence su

关键词： pedogenesis magnetic iron oxides dissolution rock magnetism diffuse reflectance spectroscopy Chinese loess

Magnetic discrimination between Al-substituted hematites synthesized by hydrothermal and thermal dehydration methods and its geological significance

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Magnetic discrimination between Al-substituted hematites syn...

中国科学院地质与地球物理研究所2012年度（第12届）学术年会

作者： Zhaoxia Jiang Qingsong Liu vidal barron Jose Torrent Yongjae Yu State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences Graduate School of the Chinese Academy of Sciences Departamento de Agronomia Universidad de Cordoba Department of Geology and Earth Environmental Sciences Chungnam National University

[1]Hematite,a ubiquitous mineral in aerobic sediments and soils of temperate and warm areas,is weakly ***,it carries a stable natural remanent magnetization,and thus can reflect paleoenvironment *** quantify the influence of Al content in hematite on its magnetic properties,two series of hematite particles were prepared by hydrothermal transformation of fenrihydrite in aqueous suspension(HFh* series) and by

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Testing the magnetic proxy XFD/HIRM for quantifying paleoprecipitation in modern soil profiles from Shaanxi Province,China

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Testing the magnetic proxy XFD/HIRM for quantifying paleopre...

中国科学院地质与地球物理研究所2013年度（第13届）学术年会

作者： Zhifeng Liu Qingsong Liu José Torrent vidal barron Pengxiang Hu State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences Graduate University of Chinese Academy of Sciences Departamento de Agronomia Universidad de CordobaEdificio C4Campus de Rabanales14071 CordobaSpain

Soils are natural archives of paleoclimates,especially for *** magnetic parameters of soils are of great interest for paleoenvironmental and paleoclimatic ***,magnetite, maghemite,hematite,and goethite are the main minerals controlling the magnetic properties of soils. The application of magnetic methods in large areas is,however,limited due to the potential effects of parent ***,magnetic measurements were conducted on modern soil profiles along a North-South transect in Shaanxi Province,China,to test a new magnetic proxy,defined as the ratio between the absolute frequency dependent susceptibility and the hard isothermal remanence magnetization(x/HIRM)for paleoprecipitation *** specifically,xand HIRM were used as semi-quantitative proxies for the ferrimagnets(magnetite and maghemite)and hematite concentrations,*** proxy x/ HIRM,estimated from the scatter plots of xand HIRM ranges between 4.5 and 97.6×10mAand systematically increases with the mean annual precipitation(MAP)fiom 300 to 1000 mm(x/HIRM= 0.124×MAP-31.5,R=0.92)with an error of±70 mm for the paleoprecipitation estimation,but is less related to mean annual temperature(MAT)(R=0.29 for a MAT range of 8-15℃).For MAP1000 mm, the x/HIRM value was only 17.8×10mAas the likely result of reductive dissolution or alteration,the effect being more marked for ferrimagnets than for *** summary,this new paleoclimatic transfer function has potential to predict MAP for Holocene soils with MAP<1000 mm,providing that there is no reductive dissolution or alteration of the iron oxides and the effect of other influential factors(***

关键词： magnetic proxy paleoprecipitation climate transfer function modern soil

Quantification of Al-goethite from diffuse reflectance spectroscopy and magnetic methods

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Quantification of Al-goethite from diffuse reflectance spect...

Pressure demagnetization of synthetic Al substituted hematite and its implications for planetary studies

中国科学院地质与地球物理研究所2014年度（第14届）学术年会

作者： Zhaoxia Jiang Qingsong Liu Claudio Colombo vidal barron Jose Torrent Pengxiang Hu State Key Laboratory of Lithospheric Evolution Institute of Geology and GeophysicsChinese Academy of Sciences University of the Chinese Academy of Sciences Universita del Molise Dip.di Agricoltura Alimentazione ed Ambientev.De SanctisI-86100 Campobasso (CB)Italy Departamento de Agronom?a Universidad de CordobaEdificio C4Campus de RabanalesE-14071 CordobaSpain

As one of the most abundant iron oxides in soils, the presence and nature of goethite is controlled by the soil conditions and burial history. The visible diffuse reflectance spectroscopy(DRS) is a useful tool for quantifying goethite. However, aluminium(Al) substitution for goethite is very common in soils and the effects of Al content on the DRS properties of goethite have not been fully resolved. In this study, two series of Al substituted goethites(Al-goethite) and 20 Chinese loess/palaeosol samples were investigated using both DRS and magnetic methods to test the feasibility of quantifying Al-goethite with the DRS *** show that the peak positions and amplitudes of the goethite DRS band are significantly influenced by Al substitution. Specifically, the goethite concentration proxy, the amplitude of the DRS band, is relatively stable only when Al substitution ranged between about 4 and16 mol per cent. Practically, in order to resolve the difficulty in measuring Al content in natural samples, the unblocking temperature(T b) is proposed as the proxy for Al substitution of goethite. When T b of Al-goethite was above 250 K, the amplitude of DRS can be used to reliably trace the goethite concentration variation in natural samples. For example, the DRS spectra for the Chinese loess–palaeosol samples support the idea that only haematite is enhanced via pedogenesis. In contrast, the origin of goethite seems to be mostly related to the aeolian inputs.

关键词： Environmental magnetism Magnetic mineralogy and petrology Rock and mineral magnetism

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Pressure demagnetization of synthetic Al substituted hematit...

中国科学院地质与地球物理研究所2013年度（第13届）学术年会

作者： Zhaoxia Jiang Pierre Rochette Qingsong Liu Jerome Gattacceca Yongjae Yu vidal barron José Torrent State Key Laboratory of Lithosphefic Evolution Institute of Geology and GeophysicsChinese Academy of Sciences University of The Chinese Academy of Sciences Aix-Marseille Universite State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics.Chinese Academy of Sciences Department of Earth Atmospheric and Planetary SciencesMassachusetts Institute of Technology Department of Geology and Earth Environmental Sciences Chungnam National University Departamento de Agronomia Universidad de CordobaCampus de Rabanales14071 CordobaSpain

Magnetic minerals can undergo high pressures during their formation and subsequent evolution,which can modify both their intrinsic magnetic properties and remanent ***-substituted hematite(Al-hematite)occurs in significant proportion in many soils and sediments,especially in temperate and warm *** this work we investigated the effect of high hydrostatic pressures on the magnetic remanence of two series of synthetic Al-hematites.A pressure of 1.44 GPa resulted in 50% reduction of the isothermal remanent magnetization(IRM),which was more effective than alternating field(AF)demagnetization with the largest peak field of 120 *** addition,repeated application of the same pressure leads to further *** substitution may increase the resistance to the pressure effect by decreasing particle size and generating defects in magnetic lattices,which results in an increase in *** study contributes to understanding the effects of pressure on rocks from the interior of Earth and other planets as well as shocked planetary surfaces,which is significant for future planetary studies.

关键词： Pressure demagnetization Hematite Aluminum substitution Hydrostatic pressure Remanent magnetization

Differential response of injured and healthy retinas to syngeneic and allogeneic transplantation of a clonal cell line of immortalized olfactory ensheathing glia:a double-edged sword

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Neural Regeneration Research 2025年第8期20卷 2395-2407页

作者： María Norte-Muñoz María Portela-Lomba Paloma Sobrado-Calvo Diana Simón Johnny Di Pierdomenico Alejandro Gallego-Ortega Mar Pérez JoséMCabrera-Maqueda Javier Sierra Manuel vidal-Sanz María Teresa Moreno-Flores Marta Agudo-Barriuso Grupo de Investigación Oftalmología Experimental Departamento de OftalmologíaOptometríaOtorrinolaringología y Anatomía PatológicaFacultad de MedicinaUniversidad de MurciaInstituto Murciano de Investigación Biosanitaria(IMIB)Campus de Ciencias de la SaludMurciaSpain Experimental Sciences Faculty Universidad Francisco de VitoriaPozuelo de AlarcónMadridSpain Anatomy Histology and Neuroscience DepartmentMedicine FacultyUniversidad Autónoma de MadridMadridSpain Center of Neuroimmunology Service of NeurologyLaboratory of Advanced Imaging in Neuroimmunological DiseasesHospital Clínic of BarcelonaInstitut d’Investigacions Biomèdiques August Pi i Sunyer(IDIBAPS)and Universitat de BarcelonaBarcelonaSpain Medicine Faculty Universidad Francisco de VitoriaPozuelo de AlarcónMadridSpain

Olfactory ensheathing glia promote axonal regeneration in the mammalian central nervous system,including retinal ganglion cell axonal growth through the injured optic ***,it is unknown whether olfactory ensheathing glia also have neuroprotective *** ensheathing glia express brain-derived neurotrophic factor,one of the best neuroprotectants for axotomized retinal ganglion ***,we aimed to investigate the neuroprotective capacity of olfactory ensheating glia after optic nerve *** ensheathing glia cells from an established rat immortalized clonal cell line,TEG3,were intravitreally injected in intact and axotomized retinas in syngeneic and allogeneic mode with or without microglial inhibition or immunosuppressive *** and gene expression analyses were *** bulb-derived primary olfactory ensheathing glia and TEG3 express major histocompatibility complex classⅡ*** and syngenically transplanted TEG3 cells survived in the vitreous for up to 21 days,forming an *** axotomized retinas,only the allogeneic TEG3 transplant rescued retinal ganglion cells at 7 days but not at 21 *** these retinas,microglial anatomical activation was higher than after optic nerve crush *** intact retinas,both transplants activated microglial cells and caused retinal ganglion cell death at 21 days,a loss that was higher after allotransplantation,triggered by pyroptosis and partially rescued by microglial inhibition or ***,neuroprotection of axotomized retinal ganglion cells did not improve with these *** different neuroprotective properties,different toxic effects,and different responses to microglial inhibitory treatments of olfactory ensheathing glia in the retina depending on the type of transplant highlight the importance of thorough preclinical studies to explore these variables.

关键词： cell therapy immune recognition major histocompatibility complex class II(MHCII) neuroprotection olfactory ensheathing glia retinal ganglion cells

Sharp Bounds for Fractional One-sided Operators

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Acta Mathematica Sinica,English Series 2016年第11期32卷 1255-1278页

作者： Maria Silvina RIVEROS Raul Emilio vidal FaMAF-CIEM UNC-CONICET Ciudad Universitaria 5000 Cdrdoba Argentina

In this paper, we characterize the sharp boundedness of the one-sided fractional maximal function for one-weight and two-weight inequalities. Also a new two-weight testing condition for the one-sided fractional maximal function is introduced extending the work of Martin-Reyes and de la Torre. Improving some extrapolation result for the one-sided case, we get weak sharp bounded estimates for one-sided fractional maximal function and weak and strong sharp bounded estimates for one-sided fractional integral.

关键词： One-sided fractional integrals one-sided maximal fractional function extrapolation Saw-yer weights

On the effectiveness of dry drainage in soil salinity control

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Science China(Technological Sciences) 2009年第11期52卷 3328-3334页

作者： VINCENT Bernard BOUARFA Sami vidal Alain Cemagref BP 44 92163 Antony Cedex France Cemagref 361 rue Jean-Franois Breton BP 5095 34196 Montpellier Cedex 5 France

Dry drainage is thought to be a potential approach to control soil salinity. This study took the Hetao Irrigation District as an example and evaluated the effectiveness of dry drainage by using remote sensing, a conceptual model and a field experiment. Archived remote sensing images from 1973―2006 were used to delineate the temporal and spatial change of soil salinity. The conceptual water and salt balance model was used to evaluate the role of dry drainage in removing excess salt from the irrigated land. The field experiment was performed to get field validation and give more accurate estimation. The results show that dry drainage did contribute to remove excess salt from the irrigated land and succeed in controlling soil salinity in the Hetao Irrigation District. It can be taken as an alternative approach in (semi-)arid area where artificial drainage is not applicable.

关键词： soil salinity dry drainage remote sensing conceptual model field experiment

Meiotic abnormalities in metaphase I human spermatocytes from infertile males： frequencies, chromosomes involved, and relationship with polymorphic karyotype and seminal parameters

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Asian Journal of Andrology 2014年第6期16卷 838-844页

作者： Zaida Sarrate Francesca vidal Joan Blanco Unitat de Biologia Cel.lular Facultat de Biociencies Universitat Autonoma de Barcelona Bellaterra (Cerdanyola del Valles) 08193 Spain.

The aim of this study was to look in depth at the relationship between meiotic anomalies and male infertility, such as the determination of the chromosomes involved or the correlation with patient features. For this purpose, a total of 31 testicular tissue samples from individuals consulting for fertility problems were analyzed. Metaphase I cells were evaluated using a sequential methodology combining Leishman stained procedures and multiplex fluorescence in situ hybridization protocols. The number of chromosomal units and chiasmata count per bivalent were established and a hierarchical cluster analysis of the individuals was performed. The relationship of the seminogram and the karyotype over recombination were evaluated using Poisson regression models. Results obtained in this study show a significant percentage of infertile individuals with altered meiotic behavior, mostly specified as a reduction in chiasmata count in medium and large chromosomes, the presence of univalents, and the observation of tetraploid metaphases. Moreover, the number and the type of anomalies were found to be different between cells of the same individual, suggesting the coexistence of cell lines with normal meiotic behavior and cell lines with abnormalities. In addition, chromosomal abnormalities in metaphase I are significantly associated with oligozoospermia and/or polymorphic karyotype variants.

关键词： chiasmata count human spermatocytes multiplex fluorescence in situ hybridization polymorphic karyotype seminalparameters