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Demographic variation and habitat specialization of tree species in a diverse tropical forest of Cameroon

Forest Ecosystems 2014年第4期1卷 201-213页

作者： David Kenfack George B Chuyong Richard Condit Sabrina E Russo duncan w Thomas Center for Tropical Forest Science - Forest GEO Botany Department Smithsonian Tropical Research Institute Department of Botany and Plant Physiology University of Buea Center for Tropical Forest Science Smithsonian Tropical Research Institute School of Biological Sciences University of Nebraska Department of Biological Sciences Washington State University

Background： Many tree species in tropical forests have distributions tracking local ridge-slope-valley topography. Previous work in a 50-ha plot in Korup National Park, Cameroon, demonstrated that 272 species, or 63% of those tested, were significantly associated with topography. Methods： we used two censuses of 329,000 trees ≥1 cm dbh to examine demographic variation at this site that would account for those observed habitat preferences. we tested two predictions. First, within a given topographic habitat, species specializing on that habitat （＇residents＇） should outperform species that are specialists of other habitats （＇foreigners＇）. Second, across different topographic habitats, species should perform best in the habitat on which they specialize （＇home＇） compared to other habitats （＇away＇）. Species＇ performance was estimated using growth and mortality rates. Results： In hierarchical models with species identity as a random effect, we found no evidence of a demographic advantage to resident species. Indeed, growth rates were most often higher for foreign species. Similarly, comparisons of species on their home vs. away habitats revealed no sign of a performance advantage on the home habitat. Conclusions＂ we reject the hypothesis that species distributions along a ridge-valley catena at Korup are caused by species differences in trees _〉1 cm dbh. Since there must be a demographic cause for habitat specialization, we offer three alternatives. First, the demographic advantage specialists have at home occurs at the reproductive or seedling stage, in sizes smaller than we census in the forest plot. Second, species may have higher performance on their preferred habitat when density is low, but when population builds up, there are negative density-dependent feedbacks that reduce performance. Third, demographic filtering may be produced by extreme environmental conditions that we did not observe during the census interval.

关键词： tree Demographic variation and habitat specialization of tree species in a diverse tropical forest of Cameroon Figure

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High-efficiency circularly polarized emission from liquid-crystalline platinum complexes

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Chinese Chemical Letters 2023年第6期34卷 310-314页

作者： Peng Fan Zhou Fang Shengyue wang Qiwei Dong Chen Xiao Alice J.McEllin duncan w.Bruce weiguo Zhu Yafei wang Jiangsu Key Laboratory of Environmentally Friendly Polymeric Materials Jiangsu Collaborative Innovation Center of Photovoltaic Science and EngineeringJiangsu Engineering Laboratory of Light-Electricity-Heat Energy-Converting Materials and ApplicationsSchool of Materials Science&EngineeringChangzhou UniversityChangzhou 213164China Department of Chemistry University of YorkYork YO105DDUnited Kingdom Anhui Sholon New Material Technology Co. Ltd.Chuzhou 239500China

Realizing both a high emission efficiency and luminescence dissymmetry factor(g_(lum))in circularly polarized solution processable organic light-emitting diodes(CP-OLEDs)remains a significant *** this contribution,two chiral phosphorescent liquid crystals based on cyclometalated platinum complexes are prepared,in which the chiral s-2-methyl-1-butyl group is introduced into the cyclometalating ligand and the mesogenic fragment is attached to the periphery of the ancillary *** platinum complexes exhibit both smectic and chiral nematic phases as evidenced by polarized optical microscopy,differential scanning calorimetry and small-angle X-ray ***,a high photoluminescent quantum efficiency of over 78%and clear circularly polarized luminescent signal with g_(PL)of about 10^(-2)are observed for the ***,solution-processed CP-OLEDs show maximum external quantum efficiencies(EQE)of over 15%and strong circularly polarized electroluminescent signals with a g_(EL)≈10^(-2).This research demonstrates that both liquid crystallinity and the number of chiral centers play key roles in improving the chiroptical property,paving the way for a new approach for the design of high-efficiency CPL emitters.

关键词： Circularly polarized emission Liquid-crystalline Platinum complex Organic light-emitting diodes

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SnapshotPrune: A Novel Bitcoin-Based Protocol Toward Efficient Pruning and Fast Node Bootstrapping

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Tsinghua Science and Technology 2024年第4期29卷 1037-1052页

作者： Pengfei Huang Xiaojun Ren Teng Huang Arthur Sandor Voundi Koe duncan S wong Hai Jiang Institute of Artificial Intelligence and Blockchain Guangzhou UniversityGuangzhou 510006China Institute of Artificial Intelligence and Blockchain Guangzhou UniversityGuangzhou 510006Chinaand also with Pazhou LabGuangzhou 510330China

Node synchronization is essential for the stability of the Bitcoin network. Critics have raised doubts about the ability of a new node to quickly and efficiently synchronize with the Bitcoin network and alleviate the storage pressure from existing full nodes to stockpile new data. Basic pruning and other techniques have been explored to address these concerns but have been insufficient to reduce node synchronization delay and effectively suppress the growth of synchronized data. In this study, we propose SnapshotPrune, a novel pruning and synchronization protocol that achieves fast node bootstrapping in the Bitcoin blockchain. Real Bitcoin historical data are leveraged to measure the synchronization time and monitor the network traffic during node bootstrapping. The protocol requires data downloads that are 99.70% less than Bitcoin Core, 81% less than CoinPrune, and 60% less than SnapshotSave, thereby saving 97.23% of download time. Findings show that the proposed design enhances the storage efficiency and reduces the node synchronization delay compared with existing techniques. we hypothesize that the efficiency of this protocol increases with the block height.

关键词： synchronization blockchain Unspent Transaction Output(UTXO)pruning snapshot fast bootstrapping

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Cannabinoids and endocannabinoids as therapeutics for nervous system disorders:preclinical models and clinical studies

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Neural Regeneration Research 2024年第4期19卷 788-799页

作者： R.Scott duncan Sean M.Riordan Matthew C.Gernon Peter Koulen Department of Ophthalmology School of MedicineUniversity of Missouri Department of Biomedical Sciences School of MedicineUniversity of Missouri

Cannabinoids are lipophilic substances derived from Cannabis sativa that can exert a variety of effects in the human *** have been studied in cellular and animal models as well as in human clinical trials for their therapeutic benefits in several human *** of these include central nervous system(CNS)diseases and dysfunctions such as forms of epilepsy,multiple sclerosis,Parkinson’s disease,pain and neuropsychiatric *** addition,the endogenously produced cannabinoid lipids,endocannabinoids,are critical for normal CNS function,and if controlled or modified,may represent an additional therapeutic avenue for CNS *** review discusses in vitro cellular,ex vivo tissue and in vivo animal model studies on cannabinoids and their utility as therapeutics in multiple CNS *** addition,the review provides an overview on the use of cannabinoids in human clinical trials for a variety of CNS *** and endocannabinoids hold promise for use as disease modifiers and therapeutic agents for the prevention or treatment of neurodegenerative diseases and neurological disorders.

关键词： anandamide cannabidiol cannabinoid endocannabinoid epilepsy multiple sclerosis neurodegeneration neuroprotection tetrahydrocannabinol

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硅光电二极管的新发展

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激光与红外 1975年第10期 667-668页

作者： F.w.duncan 苗海

1.硅光电二极管的新发展在各种波长(蓝、近紫外)激光器迅速发展情况下,探测这些波长的激光硅光电二极管有了新的发展。蓝、近紫外激光的新应用是,用可调染料激光器进行吸收研究,对于有机分子键的分解和激光多普勒测速。 2.新产品性能新... 详细信息

1.硅光电二极管的新发展在各种波长(蓝、近紫外)激光器迅速发展情况下,探测这些波长的激光硅光电二极管有了新的发展。蓝、近紫外激光的新应用是,用可调染料激光器进行吸收研究,对于有机分子键的分解和激光多普勒测速。 2.新产品性能新型的硅光电二极管是通过平面扩散、氧钝化制备的,响应率改进了20％～57％。美国联合探测器技术公司目前已进入试生产。表1是该公司生产的硅光电二极管样品的预计性能,从蓝光到近紫外的激光波长有

关键词：响应率噪音激光波长近紫外激光器噪声语音光激射器电子器件等效功率硅光电二极管

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Understanding the catalysis of chromium trioxide added magnesium hydride for hydrogen storage and Li ion battery applications

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Journal of Magnesium and Alloys 2024年第3期12卷 1117-1130页

作者： D.Pukazhselvan IhsanÇaha Catarina de Lemos Sergey M.Mikhalev Francis Leonard Deepak duncan Paul Fagg Department of Mechanical Engineering TEMA-Centre for Mechanical Technology and AutomationUniversity of AveiroAveiro 3810-193Portugal LASI-Intelligent Systems Associate Laboratory Guimarães 4800-058Portugal Nanostructured Materials Group International Iberian Nanotechnology Laboratory(INL)Avenida Mestre Jose VeigaBraga 4715-330Portugal

This study explores how the chemical interaction between magnesium hydride(MgH_(2))and the additive CrO_(3) influences the hydrogen/lithium storage characteristics of MgH_(2).we have observed that a 5 wt.%CrO_(3) additive reduces the dehydrogenation activation energy of MgH_(2) by 68 kJ/mol and lowers the required dehydrogenation temperature by 80℃.CrO_(3) added MgH_(2) was also tested as an anode in an Li ion battery,and it is possible to deliver over 90%of the total theoretical capacity(2038 mAh/g).Evidence for improved reversibility in the battery reaction is found only after the incorporation of additives with MgH_(2).In depth characterization study by X-ray diffraction(XRD)technique provides convincing evidence that the CrO_(3) additive interacts with MgH_(2) and produces Cr/MgO *** free energy analyses confirm the thermodynamic feasibility of conversion from MgH_(2)/CrO_(3) to MgO/Cr,which is well supported by the identification of Cr(0)in the powder by X ray photoelectron spectroscopy(XPS)*** high resolution transmission electron microscopy(HRTEM)and energy dispersive spectroscopy(EDS)we found evidence for the presence of 5 nm size Cr nanocrystals on the surface of MgO rock salt *** is also convincing ground to consider that MgO rock salt accommodates Cr in the *** observations support the argument that creation of active metal–metal dissolved rock salt oxide interface may be vital for improving the reactivity of MgH_(2),both for the improved storage of hydrogen and lithium.

关键词： Hydrogen storage Rechargeable batteries Binary hydrides Metal oxides Catalytic mechanism.

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临床放射生物学

临床放射生物学

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作者：邓肯(w. duncan) 尼亚斯(A. Nias)

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临床放射生物学

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1982年

作者：（英）邓肯（w. duncan）（英）尼亚斯（A.H.w. Nias）刘树铮译

本书写了放射治疗与手术治疗,化学治疗这三当今临床上治疗癌症的重要手段

ISBN: (纸本)14119·1056

本书写了放射治疗与手术治疗,化学治疗这三当今临床上治疗癌症的重要手段

关键词：临床放射医学:放射生物学地点:英国放射生物学:临床放射医学

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Quantitative assessment of the impact of a triage physician on the Accreditation Council for Graduate Medical Education resident milestones in the emergency department

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world Journal of Emergency Medicine 2024年第3期15卷 220-222页

作者： Julie Cueva duncan Grossman Vishnu Muppala Arlene Chung Mahlaqa Butt Jefferson Drapkin Antonios Likourezos Errel Khordipour Department of Emergency Medicine Maimonides Medical CenterNew York 11219USA

The “door-to-doctor” time for patients to be seen by a physician is an increasingly studied *** may shorten this time by implementing a triage physician (TP).The exact role of a TP may vary across *** put in preliminary orders for lab work,imaging,and treatment,and decide treatment location for further *** the prevalence of TPs grows,its effect on resident education in academic emergency departments (EDs) remains *** implemented a TP in the spring of 2016 and assessed resident physicians before and after implementation.

关键词： physician doctor treatment

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Considerations for the use of porcine organ donation models in preclinical organ donor intervention research

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Animal Models and Experimental Medicine 2024年第3期7卷 283-296页

作者： Frazer I.Heinis Shaheed Merani Nicholas w.Markin Kim F.duncan Michael J.Moulton Lance Fristoe william E.Thorell Raechel A.Sherrick Tami R.wells Matthew T.Andrews Marian Urban School of Natural Resources Institute of Agriculture and Natural ResourcesUniversity of Nebraska-LincolnLincolnNebraskaUSA Division of Transplantation and Vascular Surgery Department of SurgeryUniversity of Nebraska Medical CenterOmahaNebraskaUSA Department of Anesthesiology University of Nebraska Medical CenterOmahaNebraskaUSA Division of Cardiothoracic Surgery Department of SurgeryUniversity of Nebraska Medical CenterOmahaNebraskaUSA Clinical Perfusion Nebraska Medicine-Nebraska Medical CenterOmahaNebraskaUSA Department of Neurosurgery University of Nebraska Medical CenterOmahaNebraskaUSA Nutrition and Health Sciences College of Education and Human SciencesUniversity of Nebraska-LincolnLincolnNebraskaUSA Department of Comparative Medicine University of Nebraska Medical CenterOmahaNebraskaUSA

Use of animal models in preclinical transplant research is essential to the optimization of human allografts for clinical *** models of organ donation and preservation help to advance and improve technical elements of solid organ recovery and facilitate research of ischemia-reperfusion injury,organ preservation strategies,and future donor-based *** considerations include cost,public opinion regarding the conduct of animal research,translational value,and relevance of the animal model for clinical *** present an overview of two porcine models of organ donation:donation following brain death(DBD)and donation following circulatory death(DCD).The cardiovascular anatomy and physiology of pigs closely resembles those of humans,making this species the most appropriate for pre-clinical *** are also considered a potential source of organs for human heart and kidney *** is imperative to minimize animal loss during procedures that are surgically *** present our experience with these models and describe in detail the use cases,procedural approach,challenges,alternatives,and limitations of each model.

关键词： animal model brain death circulatory death organ transplantation

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