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An Introduction to Latent Variable Growth Curve Modeling 2nd ed.

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Body temperature,activity patterns and hunting in free-living cheetah:biologging reveals new insights

丛书名： Quantitative Methodology Series

2006年

作者： duncan, Terry E. duncan, Susan C. Strycker, Lisa A.

ISBN: (纸本)9780805855463

This book provides a comprehensive introduction to latent variable growth curve modeling (LGM) for analyzing repeated measures. It presents the statistical basis for LGM and its various methodological extensions, including a number of practical examples of its use. It is designed to take advantage of the reader's familiarity with analysis of variance and structural equation modeling (SEM) in introducing LGM techniques. Sample data, syntax, input and output, are provided for EQS, Amos, LISREL, and Mplus on the book's CD. Throughout the book, the authors present a variety of LGM techniques that are useful for many different research designs, and numerous figures provide helpful diagrams of the examples. Updated throughout, the second edition features three new chapters-growth modeling with ordered categorical variables, growth mixture modeling, and pooled interrupted time series LGM approaches. Following a new organization, the book now covers the development of the LGM, followed by chapters on multiple-group issues (analyzing growth in multiple populations, accelerated designs, and multi-level longitudinal approaches), and then special topics such as missing data models, LGM power and Monte Carlo estimation, and latent growth interaction models. The model specifications previously included in the appendices are now available on the CD so the reader can more easily adapt the models to their own research. This practical guide is ideal for a wide range of social and behavioral researchers interested in the measurement of change over time, including social, developmental, organizational, educational, consumer, personality and clinical psychologists, sociologists, and quantitative methodologists, as well as for a text on latent variable growth curve modeling or as a supplement for a course on multivariate statistics. A prerequisite of graduate level statistics is recommended.

关键词： Latent variables. Latent structure analysis.

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Integrative Zoology 2019年第1期14卷 30-47页

作者： Robyn S.HETEM duncan MITCHELL Brenda A.DE wITT Linda G.FICK Shane K.MALONEY Leith C.R.MEYER and Andrea FULLER School of Animal Plant and Environmental SciencesFaculty of SciencesUniversity of the WitwatersrandJohannesburgSouth Africa Brain Function Research Group School of PhysiologyFaculty of Health SciencesUniversity of the Witwatersrand Medical SchoolParktownJohannesburgSouth Africa School of Human Sciences University of Western AustraliaPerthAustralia Department of Paraclinical Science Faculty of Veterinary ScienceUniversity of PretoriaSouth Africa

As one of the few felids that is predominantly diurnal,cheetahs(Acinonyx jubatus)can be exposed to high heat loads in their natural *** is known about long-term patterns of body temperature and activity(including hunting)in cheetahs because long-term concurrent measurements of body temperature and activity have never been reported for cheetahs,or,indeed,for any free-living *** report here body temperature and locomo-tor activity measured with implanted data loggers over 7 months in 5 free-living cheetahs in *** tem-perature ranged from a maximum of 39°C in summer to−2°C in *** had higher(~0.4°C)max-imum 24-h body temperatures,later acrophase(~1 h),with larger fluctuations in the range of the 24-h body temperature rhythm(approximately 0.4°C)during a hot-dry period than during a cool-dry period,but main-tained homeothermy irrespective of the climatic *** ambient temperatures increased,the cheetahs shifted from a diurnal to a crepuscular activity pattern,with reduced activity between 900 and 1500 hours and increased nocturnal *** timing of hunts followed the general pattern of activity;the cheetahs hunted when they were on the *** hunted if an opportunity presented itself;on occasion they hunted in the midday heat or in total darkness(new moon).Biologging revealed insights into cheetah biology that are not ac-cessible by traditional observer-based techniques.

关键词： Acinonyx jubatus heat stress nocturnal intraguild predators moonlight

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大企业:高效扩展本地创新

企业家信息 2024年第1期 92-93页

作者：沙里亚尔·帕尔瓦兰德克里斯汀·科莱拉大卫·邓肯贾慧娟(翻译) 不详成长战略咨询公司

规模效应的商业优势是公认的,但大型全球企业在创新方面往往没有充分认识到这一点。一个地区或业务部门开发的创新,即受客户欢迎的新产品、吸引和留住人才的新人力资源政策、提高效率的新生产流程,这些往往都停留在这个区域或部门,而不... 详细信息

规模效应的商业优势是公认的,但大型全球企业在创新方面往往没有充分认识到这一点。一个地区或业务部门开发的创新,即受客户欢迎的新产品、吸引和留住人才的新人力资源政策、提高效率的新生产流程,这些往往都停留在这个区域或部门,而不是在整个企业中传播。

关键词：人力资源政策规模效应吸引和留住人才生产流程提高效率业务部门商业优势创新

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方茎白粉藤的细胞遗传学研究

方茎白粉藤的细胞遗传学研究

作者： duncan KIRAGU GICHUKI 中国科学院大学(中国科学院武汉植物园)

学位级别：硕士

方茎白粉藤(Cissus quadrangularis L.)属于葡萄科(Vitaceae)白粉藤属,是多年生藤本植物,茎多肉,广泛分布于非洲和南亚等干旱和半干旱地区。过去方茎白粉藤的植株或根茎一直作为药物被广泛用于人类和动物的疾病治疗。近年其整株或部分... 详细信息

方茎白粉藤(Cissus quadrangularis L.)属于葡萄科(Vitaceae)白粉藤属,是多年生藤本植物,茎多肉,广泛分布于非洲和南亚等干旱和半干旱地区。过去方茎白粉藤的植株或根茎一直作为药物被广泛用于人类和动物的疾病治疗。近年其整株或部分组织的提取物也被用于医疗和保健。同时该植物的茎也是生产天然纤维的潜在原材料。虽然该植物在分布区被广泛利用,但是对于它的细胞遗传学相关研究却鲜见报道。本研究以方茎白粉藤为主要研究材料,确定了其基因组大小和染色体数目,并利用二代测序(NGS)数据和生物信息学分析初步揭示了其基因组重复序列的特征。获得的主要结果如下;1.利用流式细胞仪评估了方茎白粉藤的基因组大小。以萝卜作为标准参照物,绘制荧光直方图(CV值小于5)。依据萝卜基因组大小和峰值读数,估算方茎白粉藤基因组大小约为2C=1.410 pg。与白粉属目前已经报道了基因组大小的其他成员相比,方茎白粉藤的基因组增加了一倍,推测可能与其进化过程中的加倍事件有关。2.以根尖为材料,采用荧光显微镜结合DAPI染色法对方茎白粉藤的染色体进行计数。由于其染色体较小,仅观察到两对染色体上的着丝粒。计数结果表明方茎白粉藤的染色体数目为2n=48。考虑到白粉藤属植物已报道的染色体基数(n=11或n=12)和其他成员已鉴定的染色体数目,加之可识别着丝粒的两对大染色体,我们推测方茎白粉藤为四倍体。3.使用改良后CTAB法从方茎白粉藤新鲜叶中提取了 DNA。通过低通量基因组测序和生物信息学分析初步揭示了方茎白粉藤的基因组组成。发现方茎白粉藤基因组由大约52%的重复序列和48%的非重复序列组成。对重复元件的注释表明长末端重复序列(LTR-反转录转座子)是其主要组分,约占重复元件的40%。对LTR的注释表明其主要由两个LTR超家族:Copia和Gypsy组成。基因组重复序列比较分析表明方茎白粉藤与其起源关系较近的葡萄属欧亚种葡萄(Vitis vinifera)之间差异显著,推测这种差异可能是由长期分化过程中的多倍化或全基因组复制等事件导致的。

关键词：方茎白粉藤基因组大小染色体数目重复序列长末端重复

Effect of screw position on bone tissue differentiation within a fixed femoral fracture

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Journal of Biomedical Science and Engineering 2013年第12期6卷 71-83页

作者： Saghar Nasr Stephen Hunt Neil A. duncan McCaig Institute for Bone and Joint Health Calgary Canada Department of Mechanical & Manufacturing Engineering Schulich School of Engineering University of Calgary Calgary Canada McCaig Institute for Bone and Joint Health Calgary Canada Department of Orthopedic Surgery University of Calgary Calgary Canada McCaig Institute for Bone and Joint Health Calgary Canada Department of Orthopedic Surgery University of Calgary Calgary Canada Department of Civil Engineering Schulich School of Engineering University of Calgary Calgary Canada

Plate and screw constructs are routinely used in the treatment of long bone fractures. Despite considerable advancements in technology and techniques, there can still be complications in the healing of long bone fractures. Non-unions, delayed unions, and hardware failures are common complications observed in clinical practice following open reduction and internal fixation of fractures [1]. Potential causes of these adverse clinical effects may be disruptive to the periosteal and endosteal blood supply, stress shielding effects, and inadequate mechanical stability. The goal of the present study was to explore the effect of screw position on the fracture healing and formation of new bone tissue with mechanoregulatory algorithms in a computational model. An idealized poroelastic 3D finite element (FE) model of a femur with a 5 mm fracture gap, including a plate-screw construct was developed. Nineteen different plate-screw combinations, created by varying the number and position of screws within the plate, were created to identify a construct with the most favourable attributes for fracture healing. The first phase of the study evaluated constructs through mechanical stress analyses to identify those constructs with high loadsupport capability. The second phase of the study evaluated healing and bone formation with a biphasic mechanoregulatory algorithm to simulate tissue differentiation for fixation within selected constructs. The results of our analysis demonstrated a 4-screw symmetrical construct with the largest distance between screws to provide the most favourable balance of stability and optimized conditions to promote fracture healing.

关键词： Femoral Fracture Internal Fixation Screw Number Screw Position Tissue Differentiation Finite Element Analysis

The Effect of the Operational Parameters on the Draft Requirement of Ripping in a Sandy Clay Soil

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Open Journal of Optimization 2016年第1期5卷 1-13页

作者： John Ndisya Ayub Gitau duncan Mbuge Angela Hiuhu Department of Environmental & Biosystems Engineering University of Nairobi Nairobi Kenya

This study set out to investigate the effect of operational parameters (i.e. ripping depth and operational speed) during a ripping operation on the draft requirement during ripping in a sandy-clay soil. Field experiments, laboratory tests and numerical modelling techniques were utilised to observe how the draft force varied with changing values of the operational parameters. The discrete element method in the EDEM AcademicTM software platform was employed to model the soil en-masse to obtain a virtual experimentation platform on which different treatments combing different settings of the operational parameters were investigated. Statistical methods, including ANOVA, regression analysis and the student t-test were applied to establish the significance of the effect of the operational parameters on the draft requirement;statistical analysis revealed that the draft increased linearly with the ripping depth and operating speed suggesting that they are directly proportional. Lower values of the ripping depth and operating speed were found to give the minimum amount of the draft requirement.

关键词： Draft Requirement Discrete Element Method Numerical Simulation Specific Draft Ripping Depth Operational Speed

Large parathyroid adenoma presenting as a femoral fracture in a young male

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Case Reports in Clinical Medicine 2013年第8期2卷 457-459页

作者： duncan Light Chakri Munipalle Vijay Kurup General Surgery North Tees and Hartlepool NHS Foundation Trust Stockton on Tees UK

Parathyroid adenoma classically presents symptoms of hypercalcaemia. Here, we present a case of a rare presentation of a parathyroid adenoma in a young male patient with a pathological fracture.

关键词： Parathyroid Adenoma Hypercalcaemia Femoral Fracture

Tracking PCB Contamination in Ontario Great Lakes Tributaries: Development of Methodologies and Lessons Learned for watershed Based Investigations

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Journal of Environmental Protection 2016年第3期7卷 390-409页

作者： Nadine Benoit Alice Dove Debbie Burniston duncan Boyd Environmental Monitoring and Reporting Branch Ontario Ministry of the Environment and Climate Change Ontario Canada water Quality Monitoring and Surveillance Division Science and Technology Branch Environment Canada Ontario Canada

Project Trackdown is an investigative environmental program aimed at tracking sources of polychlorinated biphenyl (PCB) contamination in Great Lakes tributaries. The program uses a multimedia weight of evidence approach for identifying sources of PCBs to the environment. PCB concentrations in environmental media (sediment, water, suspended sediment and soil), passive samplers and/or exposed biota (mussels, young-of-the-year fish and benthic invertebrates) are used in combination to evaluate bioavailability and identify local anomalies within a tributary. These lines of evidence can be assessed with simple chemometric techniques and fingerprinting of PCB congener profiles, and, combined with anecdotal information such as land use history and tributary alterations, may be used to identify ongoing and locally controllable sources of PCBs to the Great Lakes. The program was successful at developing environmental triggers to differentiate potential source areas from background PCB conditions in urban areas, allowing efforts to focus on identifying active ongoing sources of PCB contamination. Project Trackdown has been carried out in three tributaries to Lake Ontario (Cataraqui River, Etobicoke Creek and Twelve Mile Creek) and two tributaries that flow into the Detroit River (Turkey Creek and Little River). Local ongoing PCB sources have been identified in four projects, leading to abatement or remediation measures. As a collaborative initiative between the Ontario Ministry of the Environment and Environment Canada, Project Trackdown has successfully identified several PCB sources leading to substantial cleanup efforts aimed ultimately at reducing PCB contamination to the Great Lakes.

关键词： Source Tracking PCBs Great Lakes Tributaries

Viscoelastic behavior of nanotube-filled polycarbonate:Effect of aspect ratio and interface chemistry

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International Journal of Smart and Nano Materials 2010年第1期1卷 53-68页

作者： Renée K.duncan R.Qiao J.B.Bult D.Burris L.C.Brinson L.S.Schadler Department of Materials Science and Engineering Rensselaer Polytechnic InstituteTroyNYUSA Department of Mechanical Engineering Northwestern UniversityEvanstonILUSA Department of Mechanical Engineering University of DelawareNewarkDEUSA

A combined experimental and modeling study on the solid-state rheology of multi-walled carbon nanotube(MwNT)/polycarbonate composites as a function,independently,of MwNT aspect ratio and interface chemistry was carried *** aspect ratio nanotubes lead to greater broadening of the loss modulus peak in frequency space,but there was no effect of aspect ratio on the glass transition *** breadth of the loss modulus peak was found to correlate with the free space parameter,a measure of the spacing between the MwNTs.A new model that accounts for the aspect ratio and distribution in a representative volume element was developed to study these parameters in a controlled setting where morphology was precisely *** modeling was found to correlate well with experimental *** results shed light on the separate impacts of aspect ratio,dispersion,and interface modification on the solid-state rheology of nanofilled polymers.

关键词： polymer composite material nanotube dynamic mechanical analysis aspect ratio rheology