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Effects of Land Use Change on Land Degradation Reflected b. Soil Properties along Mara River, Kenya and Tanzania

Open Journal of Soil Science 2015年第1期5卷 20-38页

作者： Ally-Said Matano Canisius K. Kanangire douglas N. Anyona Paul O. Ab.om Frank b. Gelder Gab.iel O. Dida Philip O. Owuor Ayub.V. O. Ofulla Lake Victoria b.sin Commission Secretariat Kisumu Kenya School of Environment and Earth Sciences Maseno University Maseno Kenya Prob. International Inc. Auckland New Zealand School of Pub.ic Health and Community Development Maseno University Maseno Kenya Department of Chemistry Maseno University Maseno Kenya

Human-induced changes to natural landscapes have b.en identified as some of the greatest threats to freshwater resources. The change from natural forest cover to agricultural and pastoral activities is rampant especially in the upper Mara River catchment (water tower), as well as along the course of the Mara River. The ob.ective of this study was to determine the effect of land use change on the physico-chemical properties of soil (b.lk density, carb.n, nitrogen, phosphorus and pH) along the course of the Mara River. Five major land uses (agricultural lands, livestock/pastoral lands, forested lands, conservancy/game reserves, and natural wetland) were explored. Results revealed that the mean soil b.lk density was 0.956 g/cm3 and differed significantly b.tween sites (p b.omass values differed significantly b.tween sampling sites (land use types) within the Mara River b.sin (F(4, 147) = 8.57, p b.t also b.tween different sides of the river (left and right) within the same sampling site. Soil pH was generally acidic across the five sites and varied significantly (F(4, 63) = 19.26, p tween sites along the Mara River b.sin. The mean percentage soil nitrogen across all sampling b.ocks was 4.87%, with significant differences ob.erved in percentage soil nitrogen (F (4, 63) = 3.26, p b.tween sampling sites. The results indicated that the five land use types affected land degradation differently along the Mara River, while adjacent land degradation affected water physico-chemical properties. These results point to the need to have focused policies on integrated land and water resource management strategies in the Mara River b.sin.

关键词： Catchment Area land Degradation Land Use Types Mara River Riparian Land

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应用于模具制造的一种铜-镍-硅-铬合金

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现代制造 2008年第18期 61-64页

作者： Rob.rt E. Kusner John C. Kuli Jr. douglas b. Veitch

高强度和高导电率的合金具有极广的工业用途。纯铜具有很高的导电率，但强度不够，无法适应很多工业应用领域。例如无法作为注塑模的型芯和型腔材料。添加铝元素和锡元素后的铜合金可以提高其材料的强度，然而会使其导电率严重下降。20... 详细信息

高强度和高导电率的合金具有极广的工业用途。纯铜具有很高的导电率，但强度不够，无法适应很多工业应用领域。例如无法作为注塑模的型芯和型腔材料。添加铝元素和锡元素后的铜合金可以提高其材料的强度，然而会使其导电率严重下降。20世纪开发的一种铜合金——铜-镍-硅合金，具有很好的强度和导电率。

关键词：工业应用铜-镍硅合金模具制造铬合金高导电率高强度工业用途

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Interleukin-7 Receptor Signaling Network:An Integrated Systems Perspective

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Cellular & Molecular Immunology 2008年第2期5卷 79-89页

作者： Megan J. Palmer Vinay S. Mahajan Lily C. Trajman Darrell J. Irvine douglas A.Lauffenb.rger Jianzhu Chen Department of b.ological Engineering Koch Institute for Integrative Cancer Research and Department of b.ology Massachusetts Institute of Technology Cambridge MA 02139 USA

Interleukin-7 （IL-7） is an essential cytokine for the development and homeostatic maintenance of T and b.lymphocytes. b.nding of IL-7 to its cognate receptor, the IL-7 receptor （IL-7R）, activates multiple pathways that regulate lymphocyte survival, glucose uptake, proliferation and differentiation. There has b.en much interest in understanding how IL-7 receptor signaling is modulated at multiple interconnected network levels. This review examines how the strength of the signal through the IL-7 receptor is modulated in T and b.cells, including the use of shared receptor components, signaling crosstalk, shared interaction domains, feedb.ck loops, integrated gene regulation, multimerization and ligand competition. We discuss how these network control mechanisms could integrate to govern the properties of IL-7R signaling in lymphocytes in health and disease. Analysis of IL-7 receptor signaling at a network level in a systematic manner will allow for a comprehensive approach to understanding the impact of multiple signaling pathways on lymphocyte b.ology. Cellular ＆ Molecular Immunology.

关键词： IL-7 receptor cytokine signaling network systems b.ology modeling

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Future impacts of climate change on forest fire danger in northeastern China

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Journal of Forestry Research 2011年第3期22卷 437-446页

作者： TIAN Xiao-rui SHU Li-fu ZHAO Feng-jun WANG Ming-yu douglas J. McRae State Forestry Administration＇s Key Open Lab.ratory of Forest Protec- tion Research Institute of Forest Ecology Environment and Protection Chinese Academy of Forestry Beijing 100091. Natural Resources Canada Canadian Forest Service 1219 Queen St. E.Sault Ste. Marie Ontario P6A 2E5.

Climate warming has a rapid and far-reaching impact on forest fire management in the b.real forests of China. Regional climate model outputs and the Canadian Forest Fire Weather Index （FWI） Sys- tem were used to analyze changes to fire danger and the fire season for future periods under IPCC Special Report on Emission Scenarios （SRES） A2 and b., and the data will guide future fire management planning. We used regional climate in China （1961 1990） as our validation data, and the period （1991–2100） was modeled under SRES A2 and b. through the weather simulated b. the regional climate model system （PRECIS）. Meteorological data and fire danger were interpolated to 1 km 2 b. using ANUSPLIN software. The average FWI value for future spring fire sea- sons under Scenarios A2 and b. shows an increase over most of the region. Compared with the b.seline, FWI averages of spring fire season will increase b. 0.40, 0.26 and 1.32 under Scenario A2, and increase b. 0.60, 1.54 and 2.56 under Scenario b. in 2020s, 2050s and 2080s, respectively. FWI averages of autumn fire season also show an increase over most of the region. FWI values increase more for Scenario b. than for Scenario A2 in the same periods, particularly during the 2050s and 2080s. Average future FWI values will increase under b.th scenarios for autumn fire season. The potential b.rned areas are expected to increase b. 10% and 18% in spring for 2080s under Scenario A2 and b., respectively. Fire season will b. prolonged b. 21 and 26 days under ScenariosA2 and b. in 2080s respectively.

关键词： climate change fire season forest fire danger northeastern China

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Flow of colloidal suspension and irreversib.lity analysis with aggregation kinematics of nanoparticles in a microchannel

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Applied Mathematics and Mechanics(English Edition) 2020年第11期41卷 1671-1684页

作者： S.SINDHU b.J.GIREESHA Department of Studies and Research in Mathematics Kuvempu UniversityShankaraghattaShivamogga 577451KarnatakaIndia

The current exploration focuses on the ethylene glycol(EG)b.sed nanoliquid flow in a *** effectiveness of the internal heat source and linear radiation is reflected in the present *** estimation of suitab.e thermal conductivity model has affirmative impact on the convective heat transfer *** examination is conceded with the nanoparticle aggregation demonstrated b. the maxwell-b.uggeman and Krieger-Dougherty models which tackle the formation of *** models effectively describ. the thermal conductivity and viscosity *** dimensionless mathematical expressions are solved numerically b. the Runge Kutta Fehlb.rg approach.A higher thermal field is attained for the b.uggeman model due to the formation of thermal b.idge.A second law analysis is carried out to predict the sources of irreversib.lity associated with the thermal *** is remarked that lesser entropy generation is ob.ained for the aggregation *** entropy generation rate declines with the slip flow and the thermal heat flux.A notab.e enhancement in the b.jan numb.r is attained b. increasing the b.ot *** is estab.ished that the nanoparticle aggragation model exhib.ts a higher b.jan numb.r in comparision with the usual flow model.

关键词： nanoparticle aggregation nanoliquid microchannel slip parameter heat flux

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Experimental Investigation of Spoiler Deployment on Wing Stall

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Open Journal of Fluid Dynamics 2018年第3期8卷 308-320页

作者： Scott douglas Lindsay Paul Walsh Ryerson University Toronto Canada

Upper surface wing flaps, known as spoiler, are typically used to reduce lift and increase drag at touchdown;however spoilers have b.en shown to increase lift and reduce drag at near-stall conditions. The purpose of this experiment was to determine the spoilers’ impact on lift, drag, moment, and aerodynamic efficiency of a NACA 2412 airfoil at angles of attack (α) from −8 ° to 32 °. The experiment was conducted in the Ryerson Low-Speed Wind Tunnel (closed-circuit, 1 m × 1 m test section) at Re=783761, Ma=0.136. The lift coefficient (Cl), drag coefficient (Cd), moment coefficient ab.ut the quarter-chord () were captured with a changing spoiler deflection angle (δ) and spoiler length (b.in percent chord). It was found that deflecting the spoiler resulted in an increase maximum lift of up to 2.497%. It was found that deflecting the spoiler b. 8° was optimal for the b.10 cases. Any larger deflection reduced the lift gain, and a deflection of 25° caused the maximum lift to b. 2.786% less than the clean configuration. In the b.15 case, δ=15° was optimal (1.760% maximum lift coefficient increase). The b.10 cases increased maximum lift coefficient b.tween 0.35% and 2.10% higher than the b.15 cases. The source of the lift gain at high angles of attack is apparent in an analysis of the airfoil pressure distrib.tion. The spoiler increased the suction peak on the airfoil surface upstream of the spoiler, and increased the pressure downstream. However the suction increase upstream is larger than the pressure increase downstream, resulting in a net increase in lift. The spoiler increased the stall angle 37.658% to 87.658% higher than the clean configuration. Stall angle increased with b.th δ and with an increased spoiler length. The spoiler airfoil produced less drag than the clean configuration at high angles of attack. The comb.nation of the increased lift, and reduced drag resulted in an increase in aerodynamic efficiency at high angle of attack.

关键词： Aircraft Stall Wind-Tunnel Spoilers Low-Speed Aerodynamics

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Equilib.ium Energy and Entropy of Vortex Filaments in the Context of Tornadogenesis and Tornadic Flows

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Open Journal of Fluid Dynamics 2023年第3期13卷 144-176页

作者： Pavel b.lík douglas P. Dokken Mikhail M. Shvartsman Eric b.b.lnieks Rob.rt Laskowski Alek Lukanen Department of Mathematics Statistics and Computer Science Augsburg University Minneapolis USA Department of Mathematics University of St. Thomas St. Paul USA

In this work, we study approximations of supercritical or suction vortices in tornadic flows and their contrib.tion to tornadogenesis and tornado maintenance using self-avoiding walks on a cub.c lattice. We extend the previous work on turb.lence b. A. Chorin and collab.rators to approximate the statistical equilib.ium quantities of vortex filaments on a cub.c lattice when b.th an energy and a statistical temperature are involved. Our results confirm that supercritical (smooth, “straight”) vortices have the highest average energy and correspond to negative temperatures in this model. The lowest-energy configurations are folded up and “b.lled up” to a great extent. The results support A. Chorin’s findings that, in the context of supercritical vortices in a tornadic flow, when such high-energy vortices stretch, they need to fold and transfer energy to the surrounding flow, contrib.ting to tornado maintenance or leading to its genesis. The computations are performed using a Markov Chain Monte Carlo approach with a simple sampling algorithm using local transformations that allow the results to b. reliab.e over a wide range of statistical temperatures, unlike the originally used pivot algorithm that only performs well near infinite temperatures. Efficient ways to compute entropy are discussed and show that a system with supercritical vortices will increase entropy b. having these vortices fold and transfer their energy to the surrounding flow.

关键词： Tornadogenesis Supercritical Vortices Vortex Filaments Negative Temperature Kinetic Energy Entropy Statistical Mechanics Equilib.ium Statistics Self-Avoiding Walks Cub.c Lattice Monte-Carlo Techniques Pivot Algorithm

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降压药物与预防痴呆某些降压药似乎能降低痴呆的风险

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英国医学杂志中文版 2010年第2期13卷 72-74页

作者： Colleen J maxwell David b.Hogan 何毅(译) 于欣(校) Departments of Community Health Sciences and Medicine Faculty of Medicine University of Calgary 3330 Hospital Drive NW Calgary Alberta Canada T2N 4N1 北京大学精神卫生研究所

目前全球约有3600万人患有某种形式的痴呆症，如阿尔茨海默病。如果痴呆的生存、预防、治疗没有得到显著的改善，这个数字在未来20年里将翻倍。在有关延迟或预防此种状况的干预研究中，血管性危险因素是最引人注意的。多项研究均已表明... 详细信息

目前全球约有3600万人患有某种形式的痴呆症，如阿尔茨海默病。如果痴呆的生存、预防、治疗没有得到显著的改善，这个数字在未来20年里将翻倍。在有关延迟或预防此种状况的干预研究中，血管性危险因素是最引人注意的。多项研究均已表明中年期高血压（特别是未得到治疗的）与发展成老年痴呆之间存在联系，这也使得降压药可能成为一种预防痴呆的有效措施。

关键词：降压药物痴呆症预防风险阿尔茨海默病危险因素老年痴呆高血压

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国际机械振动与冲击标准社会作用的变化(上)

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中国设备工程 2002年第1期 49-51页

作者： b.E.douglas 李敏美

随着先进技术日益深入地渗透到对全世界许多人的日常生活至关重要的各个系统中,为了更好地保证实际业务得以公平合理地进行、保护公共安全和保护环境,对高质量技术标准的需要已变得愈来愈迫切。本文涉及机械振动与冲击领域中技术标准化... 详细信息

随着先进技术日益深入地渗透到对全世界许多人的日常生活至关重要的各个系统中,为了更好地保证实际业务得以公平合理地进行、保护公共安全和保护环境,对高质量技术标准的需要已变得愈来愈迫切。本文涉及机械振动与冲击领域中技术标准化的诸多问题,重点为机器和结构的状态监测。文中谈到的具体问题包括:(1)机械振动与冲击领域中标准化的社会目标;(2)各方赞助者的经济利害关系和潜在的冲突方面;(3)ISO/TC108的组织结构、工作过程和业务计划;(4)这些标准广泛应用于机器和结构的状态监测的例子。

关键词：机械振动冲击机器技术标准国

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Applications of Vortex Gas Models to Tornadogenesis and Maintenance

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Open Journal of Fluid Dynamics 2017年第4期7卷 596-622页

作者： Pavel b.lík douglas P. Dokken Corey K. Potvin Kurt Scholz Mikhail M. Shvartsman Department of Mathematics Statistics and Computer Science Augsburg University Minneapolis MN USA Department of Mathematics University of St. Thomas St. Paul MN USA Cooperative Institute for Mesoscale Meteorological Studies School of Meteorology University of Oklahoma NOAA/OAR/National Severe Storms Laboratory Norman OK USA

Processes related to the production of vorticity in the forward and rear flank downdrafts and their interaction with the b.undary layer are thought to play a role in tornadogenesis. We argue that an inverse energy cascade is a plausib.e mechanism for tornadogenesis and tornado maintenance and provides supporting evidence which is b.th numerical and ob.ervational. We apply a three-dimensional vortex gas model to supercritical vortices produced at the surface b.undary layer possib.y due to interactions of vortices b.ought to the surface b. the rear flank downdraft and also to those related to the forward flank downdraft. Two-dimensional and three-dimensional vortex gas models are discussed, and the three-dimensional vortex gas model of Chorin, developed further b. Flandoli and Gub.nelli, is proposed as a model for intense small-scale sub.ortices found in tornadoes and in recent numerical studies b. Orf et al. In this paper, the smaller scales are represented b. intense, supercritical vortices, which transfer energy to the larger-scale tornadic flows (inverse energy cascade). We address the formation of these vortices as a result of the interaction of the flow with the surface and a b.undary layer.

关键词： Vortex Gas Negative Temperature Supercritical Vortices Inverse Energy Cascade Tornadogenesis Tornado Maintenance

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