网络教学界面中的视觉传达设计

网络教学是一种以网络为媒介载体来进行教学信息传递的辅助教学形式,它是课堂教学的拓展和延伸,也是信息与技术、艺术的有机整合。网络教学界面的视觉效果直接影响教学信息传递的质量。因此,要运用视觉传达学的相关知识原理来指导网络教学界面设计,以提高教学信息传递的进程和效率。     

运用现代信息技术提高实验教学的实效

数字化、网络化、多媒体化的信息技术在现代教育中的应用已成为中国教育领域的一大热点。论述了广东商学院在信息化环境下,在法学实验教学中充分应用现代信息技术,优化实验教学手段,提高了实验教学质量。     

清代四川茶叶生产研究

四川是全国重要的茶叶生产省区之一。清代四川茶叶生产大致呈现出衰落→恢复→扩展→平稳发展→衰落的历史轨迹。川北、川东、川南的茶叶生产比较引人注目,但川西因在边茶销藏过程中有独特的地缘优势,故茶叶生产最盛。当时,川茶品类繁多,其中不乏名茶,如蒙顶茶、青城茶等。在种植、采摘、制作、收藏方面,四川茶叶生产有较精细、完整的技术体系。清末,四川茶叶加工技术得到一定改进。对清代四川茶叶生产规模与水平的估价,必须非常慎重。采取眼光向下的态度,切实了解农民的生产、生活逻辑,是一个重大的使命。     

CCL3 promotes hBMSC proliferation and inhibits exosome secretion

AIM: To explore the regulatory effect of chemokine CCL3 on exosome secretion from human bone marrow mesenchymal stem cells (hBMSCs).METHODS: hBMSCs were stimulated with chemokine CCL3 at different concentrations in vitro. The proliferation of hBMSCs was measured by CCK-8 assay and viable cell counting. Exosome secretion from hBMSCs was qualitatively analyzed by transmission electron microscope (TEM) and flow cytometry, and the quantitative analysis was carried out by flow cytometry and nanoparticle tracking analysis (NTA).RESULTS: Compared with control group, the viability of the hBMSCs detected by CCK-8 assay was increased when hBMSCs were treated with CCL3 (P<0.05). The results of viable cell counting demonstrated that the number of hBMSCs was raised in CCL3 group in a dose-dependent manner (P<0.05). The results of flow cytometry showed that hBMSCs expressed 3 CCL3-related specific receptors, CCR1, CCR5 and CCR9. Compared with control group, the fluorescence intensity of CCR9 in CCL3 group was obviously enhanced. However, no significant difference of fluorescence intensity for CCR5 and CCR1 was observed between the 2 groups. The results of NTA demonstrated that the secretion capacity of CCL3-induced hBMSCs was far less than that in control group (P<0.05). However, the microvesicles larger than 100 nm in CCL3 groups were increased (P<0.05). The above results indicated that the higher concentration of CCL3 induced the lower secretion of exosomes. In addition, the results of flow cytometry demonstrated that CCL3-induced hBMSCs showed lower quantity of CD9⁺ exosomes than those in control group (P<0.01).CONCLUSION: CCL3 promotes the proliferation of hBMSCs but depresses the secretion of exosomes in a dose-dependent manner. CCL3 affects the size distribution of exosomes and increases the number of nonfunctional microvesicles of larger than 100 nm in size. CCL3 induces the expression of CCR9 in hBMSCs.     

Implications of shared edge length between land cover types for landscape quality: the case of Midwestern US, 1940–1998

The north-central region of Indiana in the Midwestern United States was covered by deciduous forest, but was largely cleared for agriculture during the 1800s. The landscape has experienced tremendous change due to forest restoration, urban expansion, and reservoir construction since the early 1900s. At the same time, ecological health and environmental quality have been dramatically degraded in the region. We used simple landscape indices, such as land proportion, TE, and Shared Edge Length (SEL) between any two classes, to examine changes in the spatial patterning of six land cover types, including agriculture, grassland, closed-canopy forest, open-canopy forest, urban, and water, using aerial photographs dating from 1940 to 1998. The landscape’s domination by agriculture did not change (65% in 1940 and 57% in 1998), but there were net gains in area for closed-canopy forest (79%), urban (256%), and water (125%). Several landscape indices did not change much but SEL between closed-canopy forest and urban increased over seven fold, and SEL between water and urban increased over eight fold from 1940 to 1998. More forestlands and water bodies were exposed to human activities. The clumped pattern of forest, water, and urban in a landscape can be ecologically detrimental and should be considered in future land-use decisions.     

体育赛事实施项目管理的背景、问题与建议*

通过查阅文献资料、实地考察和专家访谈等方法分析了当前我国体育赛事实施项目管理的国内、国外背景;存在的问题;并针对各个问题提出相对应的解决策略,从而进一步完善我国体育赛事项目管理经验,为促进我国各项体育赛事的可持续健康发展提供参考意见。     

可持续土地整理评价体系研究

研究可持续土地整理是土地资源持续利用和经济社会生态持续发展的重要课题,而建立可持续土地整理评价体系对于保证可持续土地整理具有重要意义.阐述了可持续土地整理的内涵、评价体系构建原则、评价程序及其体系结构.     

2000-2015年中国城市土地利用效率的时空演化

[目的]研究中国2000-2015年282个地级以上城市的土地利用效率演化特征,为中国资源优化布局和土地利用效率持续提升提供参考。[方法]采用VRS-DEA模型和GIS空间分析方法,研究282个地级以上城市土地利用效率的演化特征与影响因素。[结果]①中国城市的土地利用效率处于中低水平。其中,东部城市效率最高,西部城市居次,中部城市最低;城市规模越大,效率越高,增速越快。②土地利用效率由纯技术效率和规模效率共同作用,但纯技术效率贡献力大于规模效率。东部城市和高等级城市更具有纯技术效率的优势。③土地利用效率的影响因素从建成区面积、第三产业从业人员数的投入过量,发展到固定资产投资额、第二产业从业人员数的投入过量。同时,第二产业增加值产出不足的影响显著大于第三产业。[结论]应针对不同区域、不同规模等级的城市采用差异化的路径来提升土地利用效率,如严格控制超大、特大城市的规模;有针对性的控制大城市规模;加大中等城市和小城市的纯技术要素投入。     

氨氮胁迫下凡纳滨对虾运动行为与能量分配模式变化

为研究氨氮胁迫下凡纳滨对虾(Litopenaeus vannamei)行为和能量分配的变化,将体质量为(4.89?0.27)g的凡纳滨对虾幼虾分别置于氨氮质量浓度为0.02 mg/L(对照)、1.00 mg/L、2.50 mg/L、5.00 mg/L,水温(28?0.5)℃的水族箱中养殖2周,监测其行为并对其生长、体组分和能量收支进行测定。结果表明,随氨氮浓度升高,凡纳滨对虾白昼的活动频率、游走距离呈先升后降趋势,而夜间则呈逐渐下降趋势,5.00 mg/L组白昼和夜间活动频率及游走距离均显著低于对照组(P0.05);特定生长率及摄食率均呈逐渐下降趋势,处理组显著低于对照组(P0.05);2.50 mg/L和5.00 mg/L组的凡纳滨对虾脂肪含量和能值均显著低于对照组(P0.05);各处理组摄食能量分配于生长的比例随着氨氮浓度的增大而降低,而消耗于代谢的比例随氨氮浓度增大而升高,与对照组相比,5.00 mg/L组的摄食能用于生长比例下降4.57%,用于代谢消耗的比例上升5.70%。上述结果表明,氨氮胁迫下凡纳滨对虾的夜间活动水平明显下降,摄食量减少,能量利用效率降低,生长速度减慢。     

广东乳源大峡谷自然保护区生态旅游开发的SWOT分析及对策

以广东省乳源大峡谷自然保护区为研究对象,运用SWOT分析方法,分析了乳源大峡谷自然保护区开展生态旅游的优势、劣势、机遇与挑战,并为乳源大峡谷自然保护区生态旅游开发提出了具体对策。