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Chemical composition of decomposing stumps in successive rotation of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) plantations

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Chinese Science Bulletin 2005年第22期50卷 2581-2586页

作者： HUAnG Zhiqun XU Zhihong BOYD Sue williams David Institute of Applied Ecology Chinese Academy of Sciences Beijing 110016 China Faculty of Environmental Sciences Griffith University QLD 4111 Australia School of Science Griffith University QLD 4111 Australia

Decomposition of stumps in successive rotation of Chinese fir (Cunninghamia lanceolata (Lamb.) Hook.) plantations was studied using a chronosequence approach. The results showed that decomposition rate constant of Chi- nese fir stump was 0.02695 as calculated from Olson’s model. The n content of stump increased during the first two-year decomposition. When the dead stump C/n ratio was 463.2 ± 27.3, the stumps started to release n. The pattern of P release was similar to that for n. However, K content of stumps showed a consistent declining trend over time during the whole decomposition. 13C nuclear magnetic resonance spec- troscopy with cross polarization and magic-angle spinning (13C CPMAS-nMR) was used to analyse organic carbon (C) components in decomposing stumps. The 13C CPMAS-nMR spectra of stumps displayed that stump was dominated by cellulose and hemicellulose. The spectra also showed the ac- cumulation of intensity in alkyl C, aromatic C, and carboxyl C spectral regions, which was expected as the labile cellulose and hemicellulose components in O-alkyl C spectral region were selectively decomposed first.

关键词：衫树树枝分解化学合成碳化层纤维素

Signalization options to improve capacity and delay at roundabouts through microsimulation approach:A case study on arterial roadways in Ghana

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Journal of Traffic and Transportation Engineering(English Edition) 2021年第1期8卷 70-82页

作者： Kwame Kwakwa Osei Charles Anum Adams williams Ackaah Yolanda Oliver-Commey Regional Transport Research and Education Centre Kumasi(TRECK)Department of Civil EngineeringKwame Nkrumah University of Science and TechnologyKumasiGhana Building and Road Research Institute of the Council for Scientific and Industrial Research(CSIR-BRRI) KumasiGhana Pennoni Associates Inc. PhiladelphiaPA 19103USA

Roundabouts are very useful when flows are balanced but can have operational challenges when flows *** roundabouts on arterial roadways in Ghana experience recurring congestion during peak *** four roundabouts between Ejisu Municipality and Asokwa Municipality on the n6 highway are typical of the situation found on arterials *** experience recurring long queues and delays during the peak hours and over-representation of truck rollover *** Ghana,historically,most roundabouts with capacity problems have been developed into interchanges at very high cost without consideration of other effective at-grade *** roundabouts are signalized,various configurations can be explored to enhance capacity while preserving the safety *** simulation techniques,various configurations and design options were tested for their effectiveness at two of the roundabouts,located at KnUST police station and Ejisu,with similar demand and high left turning *** objectives of this study were to a)evaluate the performance of the selected roundabouts on the corridor;b)explore alternative intersection configurations to improve capacity and *** video data collection techniques,2-h time stamped footages of AM and PM peak traffic flows were captured for two *** design parameters of the existing roundabouts,queue lengths,travel times,and approach flows were also *** models of the selected roundabouts were developed and calibrated for the baseline *** unconventional roundabout configuration,with a phase for major road through traffic were simulated and assessed for capacity,delay and queue *** results showed that signalized roundabout intersections effectively increased capacity by as much as 50%in some cases,reduced delay and queue length significantly,and maintained the benefits of roundabouts including *** performance could be further enhanced by introducing separate

关键词： Transportation Signal strategy Roundabout Road safety VISSIM microsimulation Congestion

Turbulent flow simulation of a single-blade Magnus rotor

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Advances in Aerodynamics 2021年第1期3卷 316-337页

作者： X.Bai C.Ji P.Grant n.Phillips U.Oza E.J.Avital J.J.R.williams School of Engineering and Materials Science Queen Mary University of LondonMile End RoadLondon E14NSUK Siemens Ltd. ChinaTechnologyBeijing 100102China State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China Grant Applied Sciences 3rd Floor3 Fitzhardinge StreetLondon W1H 6EUK.

This paper presents numerical studies of the Magnus effect for a kinetic turbine on a horizontal *** focus on the Magnus blade,a single self-spinning cylindrical blade is *** iterative direct-forcing immersed boundary method is employed within the Eulerian-Lagrangian framework due to its capability to treat complex and moving *** Eulerian fluid domain is discretized using the finite volume method while the Magnus rotor is represented by a set of discrete points/*** aim of the numerical studies is to provide insights for the design process and predict aerodynamic performances under various operating *** for stationary and self-spinning cylinders in turbulent flows are found to be in good agreement with published *** increasing the aspect ratio of the cylinder(simulated segment length over its diameter)from 3 to 10,a 30%drop in lift coefficient and a 22%increase in drag coefficient were observed,which is believed to be attributed to an enhancement of the three-dimensionality of the *** the Magnus rotor,key parameters such as dynamic forcing and frequency,distribution of pressure coefficient and torque have been produced for two cases with different structural designs and working *** increase of the aspect ratio from 3 to 10,stable forces are observed from the root side of the blade and the torque coefficient increases from 0.68 to 2.1,which indicates a superior performance in terms of power extraction.

关键词： Immersed boundary method Large eddy simulation Magnus effect Spinning cylinder

湖南市场和污染区稻米中As、Pb、Cd污染及其健康风险评价

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环境科学学报 2010年第11期30卷 2314-2320页

作者：雷鸣曾敏王利红 williams Paul n 孙国新湖南农业大学资源环境学院长沙410128 中国科学院生态环境研究中心北京100085 中南林业科技大学林学院长沙410004 山东省分析测试中心济南250014

为了更好地了解和评价湖南大米中As、Pb和Cd含量及其对人体的健康影响,在对湖南矿区和冶炼区水稻土壤重金属污染调查的基础上,分别以湖南各地市场大米和污染区当地生产的稻谷样品为例,对其进行重金属含量分析及对人体的健康风险评价.结... 详细信息

为了更好地了解和评价湖南大米中As、Pb和Cd含量及其对人体的健康影响,在对湖南矿区和冶炼区水稻土壤重金属污染调查的基础上,分别以湖南各地市场大米和污染区当地生产的稻谷样品为例,对其进行重金属含量分析及对人体的健康风险评价.结果表明,湖南各地市场大米样品中As、Pb和Cd的平均含量分别是0.20、0.20和0.28mg·kg-1,其中,衡阳市场大米中的As、Pb和Cd含量最高,其次是株洲和湘潭市场的大米.污染区稻谷中As、Pb和Cd含量分布均为:谷壳>糙米>精米,污染区精米中As、Pb和Cd的含量分别是0.24、0.21和0.65mg·kg-1,其中,来自衡阳常宁市水口山铅/锌矿区的稻谷样品中的As、Pb和Cd含量最高,其次是株洲清水塘冶炼区和湘潭锰矿区的稻谷.与市场大米样品相比,污染区精米中As、Pb和Cd的平均含量比市场大米样品高.无论是市场大米样品,还是从污染区稻田采集的稻米,均以衡阳地区稻米中的As、Pb和Cd污染最为严重,其次为株洲和湘潭地区.在As、Pb和Cd的健康风险评价中,Cd是湖南各地稻米中影响人体健康的主要因子,株洲和湘潭的Cd污染区达到90%以上,其次是As和Pb.

关键词：稻米重金属健康风险评价市场污染区湖南

new occurrence of Ba-REE fluorcarbonate minerals at Bayan Obo,Inner Mongolia,north China,and their mineralogical features

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Chinese Science Bulletin 1999年第15期44卷 1419-1423页

作者： M.J.Le Bas R.n.Wilson R.Branson L.S.Campbell T.C.williams P.Henderson Department of Geology University of Leicester Leicester LE1 7RH UKDepartment of Geology University of Leicester Leicester LE1 7RH UKDepartment of Geology University of Leicester Leicester LE1 7RH UKThe Natural History Museum London SW7 5BD UKThe Natural History Museum London SW7 5BD UKThe Natural History Museum London SW7 5BD UK

Ba-REE fluorcarbonate minerals from a carbonatite dyke at Bayan Obo, Inner Mongolia, north China, are first reported in this contribution, in which chemical composition, rare earth element (REE) patterns, and intergrowth relationships for these minerals have been investigated. Syntactic intergrowth or syntaxy between cebaite and cordylite, as well as cordylite and huanghoite were observed. This syntactic texture resulted from the variation of chemical composition of crystallizing agents for those minerals that crystallized directly from carbonatite magmas. It is worth noting that REE patterns of the Ba-REE fluorcarbonate minerals in the dyke are similar to those of the corresponding minerals from the ore hosted dolomite marble of the Bayan Obo giant REE-nb-Fe mineral deposit, which implies their relation in origin.

关键词： rare earth elements (REE) cebaite huanghoite cordylite syntaxy carbonatite Bayan Obo.

Herbal extracts as hepatoprotectants against acetaminophen hepatotoxicity

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World Journal of Gastroenterology 2010年第19期16卷 2448-2450页

作者： Hartmut Jaeschke C David williams Mitchell R McGill Anwar Farhood Department of Pharmacology Toxicology and Therapeutics University of Kansas Medical Center Kansas City KS 66160 United States Department of Pathology Brackenridge Hospital Austin TX 78701 United States

Many plant-derived natural products have the potential to be hepatoprotective and therefore can be used to treat acute and chronic liver diseases. The challenge is to identify the most promising compounds and evaluate their protective mechanism. In a recently published article, Wang et al evaluated extracts of the plant Gentiana manshurica Kitagawa (GM) in a model of acetaminophen hepatotoxicity. The authors concluded that GM is hepatoprotective against acetaminopheninduced liver injury due to its antioxidant properties and anti-apoptotic capacity. We would like to discuss the limitations of this experimental approach and question the conclusion based on the data presented in this manuscript and the published literature.

关键词： Acetaminophen Drug hepatotoxicity Herbal extracts n-acetylcysteine

Evolutionary Process from Mockina bidentata to Parvigondolella andrusovi:Evidence from the Pizzo Mondello Section,Sicily,Italy

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Journal of Earth Science 2021年第3期32卷 667-676页

作者： Yixing Du Tetsuji Onoue Viktor Karadi Ian S.williams Manuel Rigo Department of Geosciences University of Padova35131 PadovaItaly Department of Earth and Planetary Sciences Kyushu UniversityFukuokaJapan Department of Palaeontology Eotvos Lorand UniversityBudapest 1117Hungary Research School of Earth Sciences The Australian National UniversityACT 2601 CanberraAustralia Institute of Geosciences and Earth Resources National Research Council of Italy35131 PadovaItaly

During their last phase of evolution,the pectiniform conodont elements manifested an evident trend of simplification and *** phase started from the late norian(Sevatian)in the Late Triassic and the evolutionary process of genus Mockina to Parvigondolella,in particular between Mockina bidentata and Parvigondolella andrusovi,is one of the most significant *** has been reported worldwide since it was first described in the early ***,it has recently been suggested that genus Parvigondolella is an ecostratigraphic morphotype of genus Mockina,and thus a phenotype controlled by the environmental conditions,and not an independent *** the Pizzo Mondello Section(Sicily,Italy),transitional forms between *** and *** have been found at different evolutionary *** have investigated the oceanic conditions at the time by using redox-sensitive elements(Mn,Fe,V,Cr,and ni)and seawater temperatures from biogenetic δ^(18)Ophos to understand the possible environmental influences on the phylogenetic evolution between Mockina and *** geochemical and isotope analyses indicate that the redox condition and temperature were stable during the evolution of genus Parvigondolella in Pizzo Mondello,confirming that genus Parvigondolella is a real taxon and not a phenotype.A new conodont species named Parvigondolella ciarapicae *** described here for the first time.

关键词： conodont Late Triassic evolution oxygen isotope geochemistry

Strongly seasonal Proterozoic glacial climate in low palaeolatitudes:Radically different climate system on the pre-Ediacaran Earth

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Geoscience Frontiers 2016年第4期7卷 555-571页

作者： George E.williams Phillip W.Schmidt Grant M.Young Department of Earth Sciences University of AdelaideSA 5005Australia CSIRO Mineral Resources Flagship PO Box 52North RydeNSW 16FOAustralia Department of Earth Sciences University of Western OntarioLondonOntario N6A 5B7Canada

Proterozoic （pre-Ediacaran） glaciations occurred under strongly seasonal climates near sea level in low palaeolatitudes. Metre-scale primary sand wedges in Cryogenian periglacial deposits are identical to those actively forming, through the infilling of seasonal （winter） thermal contraction-cracks in perma- frost by windblown sand, in present-day polar regions with a mean monthly air temperature range of 40 ~C and mean annual air temperatures of -20 ~C or lower. Varve-like rhythmites with dropstones in Proterozoic glacial successions are consistent with an active seasonal freeze-thaw cycle. The seasonal （annual） oscillation of sea level recorded by tidal rhythmites in Cryogenian glacial successions indicates a significant seasonal cycle and extensive open seas. Palaeomagnetic data determined directly for Prote- rozoic glacial deposits and closely associated rocks indicate low palaeolatitudes： Cryogenian deposits in South Australia accumulated at 〈10% most other Cryogenian deposits at 〈20~ and Palaeoproterozoic deposits at 〈15~ palaeolatitude. Palaeomagnetic data imply that the Proterozoic geomagnetic field approximated a geocentric axial dipole, hence palaeolatitudes represent geographic latitudes. The Cry- ogenian glacial environment included glacier-flee, continental permafrost regions with ground frozen on a kyr time-scale, aeolian sand-sheets, extensive and long-lived open seas, and an active hydrological cycle. This palaeoenvironment confiicts with the ＇snowball Earth＇ and ＇slushball Earth＇ hypotheses, which cannot accommodate large seasonal changes of temperature near the equator. Consequently, their proponents have attempted to refute the evidence for strong seasonality by introducing Popperian ＇auxiliary assumptions＇. However, non-actualistic arguments that the Cryogenian sand wedges indicate diurnal or weakly seasonal temperature changes are based on misunderstandings of periglacial pro- cesses. Modelling of a strongly seasonal climate for a frozen-over Ear

关键词： Proterozoic Glaciation Periglacial structures Varves Paleoclimate Paleomagetism

Multiple mating by both sexes in an invasive insect species,Aethina tumida(Coleoptera:nitidulidae)

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Insect Science 2023年第2期30卷 517-529页

作者： Anna Papach Alexis Beaurepaire Orlando Yanez Meret Huwiler Geoffrey R.williams Peter neumann Institute of Bee Health Vetsuisse FacultyUniversity of BernBernSwitzerland Agroscope Swiss Bee Research CentreBernSwitzerland Department of Entomology&Plant Pathology Auburn UniversityAuburnAlabamaUSA

Multiple mating by both sexes is common among sexually reproducing *** hive beetles(SHB),Aethina tumida,are parasites of bee nests endemic to sub-Saharan Africa and have become a widespread invasive *** the considerable economic damages they can cause,their basic biology remains poorly *** we show that male and female small hive beetles can mate multiple times,suggesting that costs for mating are low in this *** an invasive *** population in the United States,a combination of laboratory experiments for males and paternity analysis with eight polymorphic DnA microsatellite markers for field-caught females were used to estimate the number of mating by both *** data show that females and males can mate multiple times—females mated with up to eight males,whereas males mated with at least seven *** results also showed that *** displayed a skewed paternity,although this was not consistent among the tested ***,first or last male advantage seem to be unlikely in *** observations that individuals of both sexes of *** can mate multiple times opens new research avenues for examining drivers of multiple mating and determining the role it may play in promoting biological invasions.

关键词： evolution of sex invasive species multiple partners polygynandry reproductive biology