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Discovery of a strongly r-process enhanced extremely metal-poor star LAMOST J110901.22+075441.8

Research in Astronomy and Astrophysics 2015年第8期15卷 1264-1274页

作者： Hai-Ning Li wako aoki Satoshi Honda Gang Zhao Norbert Christlieb Takuma Suda Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of Sciences National Astronomical Observatory of Japan 2-21-1 OsawaMitakaTokyo181-8588Japan Department of Astronomical Science School of Physical SciencesThe Graduate University of Advanced Studies (SOKENDAI)2-21-1 OsawaMitakaTokyo 181-8588Japan University of Hyogo Center for AstronomyNishigaichiSayo-choSayoHyogo679-5313Japan Zentrum für Astronomie der Universitt Heidelberg LandessternwarteKnigstuhl 12D-69117 HeidelbergGermany Research Center for the Early Universe The University of TokyoHongo 7-3-1Bunkyo-kuTokyo 113-0033Japan

We report the discovery of an extremely metal-poor（EMP） giant,LAMOST J110901.22＋075441.8, which exhibits a large excess of r-process elements with [Eu/Fe] ～＋1.16. The star is one of the newly discovered EMP stars identified from the LAMOST low-resolution spectroscopic survey and a highresolution follow-up observation with the Subaru Telescope. Stellar parameters and elemental abundances have been determined from the Subaru spectrum. Accurate abundances for a total of 23 elements including 11 neutron-capture elements from Sr through Dy have been derived for LAMOST J110901.22＋075441.8. The abundance pattern of LAMOST J110901.22＋075441.8 in the range of C through Zn is in line with the ＂normal＂ population of EMP halo stars, except that it shows a notable underabundance in carbon. The heavy element abundance pattern of LAMOST J110901.22＋075441.8 is in agreement with other well studied cool r-II metal-poor giants such as CS 22892-052 and CS 31082-001. The abundances of elements in the range from Ba through Dy match the scaled solar r-process pattern *** J110901.22＋075441.8 provides the first detailed measurements of neutroncapture elements among r-II stars at such low metallicity with [Fe/H]-3.4, and exhibits similar behavior as other r-II stars in the abundance ratio of Zr/Eu as well as Sr/Eu and Ba/Eu.

关键词： star: abundances—stars: PopulationⅡ— nucleosynthesis

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Camel management as an adaptive strategy to climate change by pastoralists in southern Ethiopia

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Ecological Processes 2017年第1期6卷 273-284页

作者： Galma wako Menfese Tadesse Ayana Angassa Wondo-Genet College of Forestry and Natural Resource Hawassa UniversityShashamaneEthiopia Department of Animal Science and Production Botswana University of Agriculture and Natural ResourcesGaboroneBotswana

Introduction:Experiences of low rainfall and frequent droughts have had enormous impacts on livestock production and pastoralists’livelihoods in southern *** Borana pastoralists are dependent on livestock husbandry with the dominance of cattle in their herds for ***,the Borana communities have engaged in extensive livestock species diversification,with more focus on camel management as an adaptation strategy to the severity of recurrent *** increasing interests in camel management among the Borana pastoralists are acknowledged,the driving forces for the increase in camel population in the region have not been *** aim of this study was to assess the trend in camel management as an adaptation strategy towards climate change among the Borana pastoral *** study also investigated evidence of climate change and the driving factors for camel ***:The study was conducted in three purposively selected kebeles,which is a lower administrative unit in Ethiopia,of Yabello district in Borana Zone in southern Ethiopia focusing on 156 randomly selected camel-owning *** study employed both quantitative and qualitative methods whereby data gathering tools such as key informant interviews(KII),focus group discussions(FGD),household surveys(HS),and field observations were *** data were analyzed by descriptive statistics using SPSS software version ***:Pastoralists’perceptions and the existing meteorological data analysis showed an increasing trend in temperature but a decreasing pattern in rainfall over the last 27 years(i.e.,during the last four Gada periods).Both pastoralists’observations and existing meteorological data analysis showed an increasing incidence of recurrent droughts with decreasing availability of grazing and water *** further explained that cattle are more vulnerable during severe *** findings also showed that camel management as an adaptation st

关键词： Climate change Camel management Pastoral households Borana Zone Southern Ethiopia

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Combustion synthesis, characterization and luminescence properties of barium aluminate phosphor

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Journal of Rare Earths 2014年第9期32卷 806-811页

作者： A.H. wako F.B Dejene H.C Swart Department of Physics University of the Free State (Qwaqwa Campus) Department of Physics University of the Free State

The blue-green emitting Eu2＋ and Nd3＋ doped polycrystalline barium aluminate （BaAI204：Eu2＋,Nd3＋） phosphor, was prepared by a solution-combustion method at 500 ℃without a post-annealing process. The characteristic variation in the structural and luminescence properties of the as-prepared samples was evaluated with regards to a change in the Ba/A1 molar ratio from 0.1：1 to 1.4：1. The morphologies and the phase structures of the products were characterized by scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, X-ray diffraction （XRD） and X-ray photoelectron spectroscopy （XPS）, while the optical properties were investigated using ultra-violet （UV） and photoluminescence （PL） spectroscopy, respectively. The XRD and TEM results revealed that the average crystallite size of the BaAl2O4：Eu2＋,Nd3＋ phosphor was about 70 urn. The broad-band UV-excited luminescence of the phosphors was observed at 2max=500 um due to transitions from the 4f^65d1 to the 4f7 configuration of the Eu2＋ ion. The PL results indicated that the main peaks in the emission and excitation spectrum of phosphor particles slightly shifted to the short wavelength due to the changes in the crystal field due to the structure changes caused by the variation in the quantity of the Ba ions in the host lattice.

关键词： BaAl2O4:Eu2+,Nd3+ persistence luminescence Eu2+ and Nd3+ doping rare earths

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Principle for obtaining high joint quality in dissimilar friction welding of Ti-6Al-4V alloy and SUS316L stainless steel

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Journal of Materials Science & Technology 2020年第11期42卷 211-224页

作者： Huihong Liu Yo aoki Yasuhiro aoki Kohsaku Ushioda Hidetoshi Fujii Joining and Welding Research Institute Osaka UniversityIbarakiOsaka 567-0047Japan

Ti-6Al-4V alloy(Ti64)and SUS316 L stainless steel rods were dissimilarly friction *** focusing on the detailed observation of interface microstructural evolution during the friction welding(FW),the relationship between the processing conditions,weld interface microstructure,and mechanical properties of the obtained joints were systematically investigated to elucidate the principle for obtaining a high joint quality in the FW of Ti64 and SUS316L.A higher friction pressure produced a lower welding temperature in the FW,hence suppressing the thick intermetallic compound layer ***,hard and brittle Ti64/SUS316L mechanically mixed layers generally formed especially at the weld interface periphery due to the high temperature increasing rate,high rotation linear velocity and high outward flow velocity of the *** harmful layers tended to induce the cracks/voids formation at the weld interfaces hence deteriorating the joints’mechanical *** rotation speed reduction and liquid CO2 cooling during the entire processing decreased the temperature increasing rate,rotation linear velocity and outward flow velocity of the Ti64 at the weld interface ***,they suppressed the formation of the harmful mechanically mixed layers,facilitated the homogeneous and sound interface microstructure generation,and finally produced a high-quality dissimilar joint in the FW of Ti64 and SUS316L.

关键词： Friction welding Titanium alloy Stainless steel Microstructure formation mechanism Mechanically mixed layers

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Baryon-Baryon interactions from lattice QCD

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Chinese Physics C 2010年第9期34卷 1236-1240页

作者： S.aoki Graduate School of Pure and Applied Sciences University of Tsukuba

We report on new attempt to investigate baryon-baryon interactions in lattice *** the Bethe-Salpeter （BS） wave function,we have successfully extracted the nucleon-nucleon （NN） potentials in quenched QCD simulations,which reproduce qualitative features of modern NN *** method has been extended to obtain the tensor potential as well as the central potential and also applied to the hyperonnucleon （YN） interactions,in both quenched and full QCD.

关键词： nucelon-nucelon potential Bethe-Salpeter wave function lattice QCD hyperon-nucleon interactions tensor potential

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s cascade reinforcement likely when sympatric tnd allopatric populations exchange migrants？

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Current Zoology 2016年第2期62卷 155-167页

作者： Roman YUKILEVICH Fumio aoki Department of Biology Union College Schenectady NY 12308 Department of Ecology and Evolution Stony Brook University Stony Brook NY 11794

When partially reproductively isolated species come back into secondary contact, these taxa may diverge in mating preferences and sexual cues to avoid maladaptive hybridization, a process known as reinforcement. This phenomenon often leads to reproductive character displacement （RCD） between sympatric and allopatric populations of reinforcing species that differ in their exposure to hybridization. Recent discussions have reinvigorated the idea that RCD may give rise to additional speciation between conspecific sympatric and allopatric populations, dubbing the concept ＂cascade reinforcement.＂ Despite some empirical studies supporting cascade reinforcement, we still know very little about the conditions for its evolution. In the present article, we address this question by developing an individual-based population genetic model that explicitly simulates cascade reinforcement when one of the hybridizing species is split into sympatric and allopatric populations. Our results show that when sympatric and allopatric populations reside in the same environment and only differ in their exposure to maladaptive hybridization, migration between them generally inhibits the evolution of cascade by spreading the reinforcement alleles from sympatry into allopatry and erasing RCD. Under these conditions, cascade reinforcement only evolved when migration rate between sympatric and allopatric populations was very low. This indicates that stabilizing sexual selection in allopatry is generally ineffective in preventing the spread of reinforcement alleles. Only when sympatric and allopatric populations experienced divergent ecological selection did cascade reinforcement evolve in the presence of substantial migration. These predictions clarify the conditions for cascade reinforcement and facilitate our understanding of existing cases in nature.

关键词： Dobzhansky-Muller incompatibilities hybrid zones reproductive character displacement reproductive isolation secondary contact sexual isolation speciation

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Attenuation and Distortion of Compression Waves Propagating in Very Long Tube

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Journal of Thermal Science 2011年第1期20卷 53-57页

作者： Shinya NAKAMURA Daisuke SASA Toshiyuki aoki Graduate School of Engineering Sciences Kyushu UniversityKasugaFukuoka816-8580Japan

A lot of phenomena related to propagating various waves are seen when the high-speed train goes through the tunnel,the gas pipeline is broken due to an accident or the air brake of the wagon *** instance,a compression wave generated ahead of a high-speed train entering a tunnel propagates to the tunnel exit and spouts as a micro pressure wave,which causes an exploding *** order to estimate the magnitude correctly,the mechanism of the attenuation and distortion of a compression wave propagating along a very long tunnel must be understood and the experimental information on these phenomena is *** experimental investigation is carried out to clarify the attenuation and distortion of the propagating compression wave in a very long *** results show that the strength of a compression wave decreases with *** attenuation and distortion of compression waves are affected by the initial waveform of the compression wave and by the unsteady boundary layer induced by the propagating *** shape of a compression wave becomes different with the propagating distance;that is,a shock wave appears just head of a wavefront and an overshoot on pressure distribution is observed behind a shock wave due to the transition of the unsteady boundary layer.

关键词： Propagating Compression Wave Very Long Tube Micro-pressure Wave High-Speed Train

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Changes over time in treatment for obstructive jaundice

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World Journal of Gastrointestinal Surgery 2024年第10期16卷 3074-3077页

作者： Hideki aoki Department of Surgery National Hospital Organization Iwakuni Clinical CenterIwakuni 740-8510YamaguchiJapan

This editorial discusses an article by Peng et *** study reviewed the efficacy and safety of a new approach for treating obstructive *** the pathophysiology of obstructive jaundice has not yet been fully elucidated,pro-gress has been made in its *** are two aspects of obstructive jaundice:Cholestatic status and absence of bile in the intestinal *** biliary drainage resolved both the ***,endoscopic retrograde biliary drainage(ERBD)has replaced percutaneous transhepatic biliary drainage,and ERBD is transitioning to endoscopic ultrasound guided biliary *** editorial briefly explains the mechanism and treatment of obstructive jaundice and the prospects of this new internal biliary drainage technique.

关键词： Obstructive jaundice Intestinal permeability Biliary drainage Endoscopic retrograde biliary drainage Endoscopic ultrasound guided biliary drainage

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Identification of CO_2 disposal locations in an ocean general circulation model of the North Pacific

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Acta Oceanologica Sinica 2009年第1期28卷 15-24页

作者： XU Yongfu aoki Shigeaki HARADA Koh State Key Laboratory of Atmospheric Boundal7 Layer Physics and Atmospheric Chemistl＇y Institute of Atmos- pheric Physics Chinese Academy of Sciences Beijing 100029 China Institute for Environmental Management Technology National Institute for kdvanced Industrial Science and Technology Tsukuha lbaraki 305-8569 Japan

A basin-wide ocean general circulation model of the North Pacific is used to identify which location is more efficient for ocean CO2 sequestration in the North *** injection depths at each one of fifteen locations are *** terms of effectiveness index（EI） and escape factor（EF）,it is clear that the effectiveness increases with increasing latitude at the end of the 50 a injection ***-by-site differences in the EI can be over 9% for the 1 000 m injection depth in the western North Pacific at the end of 50 a of continuous *** difference is much larger for the 500 m *** difference decreases with increasing injection ***,the site-by-site difference is small for the injection in the eastern North *** sequestration is more efficient for the injection in the east than in the *** the 500 m injection depth,the difference in effectiveness between the west and the east is over 10% at the end of 50 a injection *** largest concentration of sequestered CO2 increases with increasing injection *** the injection in both the western and central North Pacific,the largest exchange flux always appears to be at about 42°N,150°E,whereas for the injection in the eastern area the large flux appears to be in the equatorial region（120°W）.

关键词： ocean carbon disposal north Pacific Ocean numerical modelling sequestration

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Role of the first mitosis in the remodeling of the parental genomes in mouse embryos

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Cell Research 2005年第2期15卷 127-132页

作者： Kentaro T.HARA,Fugaku aoki Department of Integrated Biosciences Graduate School of Frontier Sciences University of Tokyo Kashiwa Chiba 277-8571 Japan Department of Integrated Biosciences Graduate School of Frontier Sciences University of Tokyo Kashiwa Chiba 277-8571 Japan

Although male and female pronuclei reside in the same zygotic cytoplasm, they differ in many respects, such asvolume and transcriptional activity. The aim of this study is to investigate whether these differences are lost during thefirst mitosis. For this purpose, a new method was developed to inhibit the mixing of two parental chromosomes duringmitosis, thus to induce the formation of two nuclei after they exit from the mitotic phase. In this method, one-cellembryos are arrested at metaphase by treatment with nocodazole, and whn exitting from the mitotic phase, two nucleiwere formed in a single karyocyte following treatment with 6-dimethylaminopurine (6-DMAP). These embryos weredesignated as post-mitotic embryos (PM-embryos), in which the two nuclei were derived from the male and femalegenomes. We found that in the control one-cell embryos that had not been treated with the reagents, the volume of themale pronucleus was about 1.65-fold greater than that of the female pronucleus, whereas the volumes of the two nucleiin the PM-embryos were similar (volume ratio of 1.01). Although a two-fold difference in transcriptional activity wasdetected between the male and female pronuclei in the control embryos, no difference in transcriptional activity wasdetected between the two nuclei of PM-embryos. The ratio of transcriptional activity in the nucleus derived from thepaternal genome to that from the maternal genome was 1.02, for which no significant difference was detected by the χ2fitness test. Therefore, the volumes and transcriptional activities of the male and female nuclei were approximately equalin PM-embryos, which suggests that the asymmetries of pronuclear volume and transcriptional activity between maleand female genomes are somehow losted during the first mitosis.

关键词： mouse zygote parental genomes nuclear volume transcriptional activity.

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