三江源地区1961−2019年降水量时空变化特征     

蔡永祥  罗少辉  王军  祁栋林  胡馨月 《草业科学》2022,39(1):10-20

利用三江源地区13个气象站1961?2019年共59年的降水量资料,基于一元线性回归、滑动平均法、气候倾向率和重标极差分析等方法,研究源区降水量的时空演变规律和未来变化趋势.结果表明:三江源地区年均降水量为470.7?mm,并以10.31?mm·10?a?1的速率增加.黄河源区春季降水量最大,其余三季以澜沧江源区最高,...  相似文献   

Use of geographical information systems as a tool for predicting fish yield in tropical reservoirs: case study on Sri Lankan reservoirs     

S. S. De Silva  U. S. Amarasinghe  & C. Nissanka  W. A. D. D. Wijesooriya  & M. J. J. Fernando 《Fisheries Management and Ecology》2001,8(1):47-60

Use of geographical information systems (GIS) in inland fisheries has hitherto been essentially restricted to site evaluation for aquaculture development and assessment of limnological changes in time and space in individual water bodies. The present GIS study was conducted on the land-use pattern of the catchments of nine reservoirs in Sri Lanka, for which detailed fishery data, viz. yield, fishing intensity, landing size of major constituent species, together with selected limnological data such as conductivity and chlorophyll- a , were available. Potential statistical relationships (linear, curvilinear, exponential and second-order polynomial) of fish yield ( FY , in kg ha⁻¹ yr⁻¹) to different land-use patterns, such as forest cover ( FC , in km²) and shrub-land ( SL , in km²), either singly, or in combination, and/or the ratio of each land type to reservoir area ( RA in km²) and reservoir capacity ( RC in km³), were explored. Highly significant relationships were evident between FY to the ratio of SL and/or FC + SL to RA and/or RC . Similarly, the above land-use types to RA and RC ratios were significantly related to limnological features of the reservoirs. The relationships of FY to various parameters obtained in this study were much better correlated than those relationships of FY to limnological and biological parameters used in yield prediction in tropical and temperate lacustrine waters previously.  相似文献   

Effect of simulated transport stress on the rat small intestine: A morphological and gene expression study   总被引：2，自引：0，他引：2  

Changrong Wan  Peng Yin  Xiaolong Xu  Mingjiang Liu  Shasha He  Shixiu Song  Fenghua Liu  Jianqin Xu 《Research in veterinary science》2014

The present study investigated the effects of simulated transport stress on morphology and gene expression in the small intestine of laboratory rats. Sprague Dawley rats were subjected to 35 °C and 0.1×g on a constant temperature shaker for physiological, biochemical, morphological and microarray analysis before and after treatment. The treatment induced obvious stress responses with significant decreases in body weight (P < 0.01), increases in rectal temperature, serum corticosterone (CORT), serum glucose (GLU), creatine kinase (CK) and lactate dehydrogenase (LDH) levels (P < 0.01), as well as expression of Hsp27/70/90 mRNA (P < 0.05; P < 0.01). The rat jejunum was severely damaged and apoptotic after mimicking transport stress, which may mainly be related to cell death, oxidation reduction and hormone imbalance determined by microarray analysis. The bioinformatics analysis from the present study would provide insight into the potential mechanisms underlying transport stress-induced injury in the rat small intestine.  相似文献   

河南省“空心村”形态特征及成因分析          下载免费PDF全文

李长印 《农学学报》2014,(5):101-105,110

河南省“空心村”分布广,数量大,占地多,并呈现出同心圆、多核心、扇形、带（条）状等多种形态.造成这种现象的原因主要有经济、制度、观念、环境等诸多方面.这种现象的存在和发展,不仅蚕食大量农田直接危及农业发展的物质基础,而且诱发许多矛盾严重妨碍农村经济社会的协调发展.因此,深入分析这种现象的成因,对科学制定村镇建设规划,节约集约利用土地资源,改善农村居住环境,保障农业可持续发展与粮食安全,都是至关重要的.  相似文献   

浅谈英语专业听力课中的英语新闻教学     

于春梅 《吉林农业科技学院学报》2014,(1):120-121

在英语专业四级、八级考试中,听力部分都占据很大的比例,但这部分也是学生的主要失分点之一,尤其是其中的英语新闻的听力理解试题,学生的得分率普遍偏低.本文从英语新闻的结构特点、词汇特点和背景知识入手,探讨了解英语新闻的结构特点、词汇特点和背景知识在英语新闻听力教学中的重要性,并针对英语新闻听力教学提出几点建议.  相似文献   

Subcutaneous Soft Tissue Sarcoma with Rhabdoid Features in a Dog     

Ayako Sayama  Keiko Okado  Masako Imaoka  Yusuke Yokouchi  Toshimasa Jindo  Wataru Takasaki 《Journal of toxicologic pathology》2014,27(2):131-138

A nine-year-old male beagle dog had a white spherical mass in the subcutis of the left lumbar region. Microscopically, spindle to oval cells diffusely proliferated in the fibrous and myxoid stroma. Many neoplastic cells showed rhabdoid features or vacuolated cytoplasm. Immunohistochemically, the neoplastic cells were positive for vimentin and S100 and partly positive for neuron-specific enolase and glial fibrillary acidic protein but were negative for von Willebrand factor, desmin and α-smooth muscle actin. Ultrastructurally, the neoplastic cells had abundant cytoplasmic processes and desmosome-like structures. Cytoplasmic inclusions of rhabdoid-featured cells in HE sections were composed of aggregates of intermediate filaments, and cytoplasmic vacuoles were identified as an invagination of cytoplasm. Although malignant peripheral nerve sheath tumor was suggested according to these results, the present case was diagnosed as a soft tissue sarcoma with rhabdoid features due to a lack of identification of the basal lamina under electron microscopy.  相似文献   

2种中国黑块菌的介绍及可持续发展研究     

龙新华  王丽  李树红  余文艺  张小雷 《中国食用菌》2014,(3):3-4

黑块菌是一类珍稀的外生菌根食用菌。着重描述印度块菌和夏块菌的形态特征和鉴别特征,并介绍它们的生境及分布区域。同时,对块菌的可持续发展提出建议。  相似文献   

红掌种质资源形态学标记与遗传多样性分析   总被引：1，自引：0，他引：1  

徐世松  王呈丹  黄素荣  张志群  黄少华  杨光穗 《热带作物学报》2014,35(10):1890-1896

为了解红掌种质资源的遗传基础,对收集的32个红掌品种的形态学性状如株高、花色、叶色等进行比较分析。基于形态学标记,这些品种的遗传多样性丰富。UPGMA聚类分析表明,这32个红掌品种可划分为5大类,其中包括4个较小的类群和1个较大的类群。本研究鉴定的一些形态学标记对于红掌品种鉴定、遗传多样性分析和杂交育种具有重要的应用价值。  相似文献   

台农1号芒果一次花和二次花的特性研究     

邢福甫  吉福桑  王令霞  李新国  曾丽萍 《安徽农学通报》2014,(22):62-64

为了探讨比较台农1号芒果“一年两熟”栽培过程中一次花和二次花的形态特性,对其一次花和二次花的花序长度、花朵直径、两性花比率、花粉活性、花粉量及花粉形态、大小进行了试验研究。结果表明：一次花和二次花的花序平均长度分别为30.74cm和20.67cm;一次花和二次花的直径平均长度分别为7.30mm和6.55mm;一次花和二次花的两性花比率较低,一次花的两性花比率为20.06%,二花的两性花比率为28.79%;一次花的花粉活性比二次花的花粉活性高,一次花的花粉活性为12.90%,二次花的花粉活性为7.63%;一次花的每花花药含花粉量为500个,二次花的每花花药含花粉量为333个;台农1号一次花和二次花的花粉形态可分为长椭圆形花粉、椭圆形花粉、近圆形花粉和不规则形花粉4个类型。  相似文献   

不同产地甘遂和醋甘遂饮片的性状和显微鉴别比较     

束晓云  王媚  王春根  张丽  丁安伟 《安徽农业科学》2014,(34):12061-12064

[目的]探索甘遂和醋甘遂饮片的快速鉴定方法.[方法]采用性状及显微鉴别的方法对不同产地甘遂和醋甘遂的饮片性状与粉末显微特征进行了比较.[结果]山西产甘遂多为细长圆柱状,且纤维性较强,陕西产多为粗短连珠状;山西产甘遂乳汁管和纤维较多,厚壁细胞壁微木化,而淀粉粒明显少于陕西产甘遂;醋甘遂饮片较生甘遂颜色深,可见焦斑;醋甘遂粉末中的木栓细胞、导管及纤维的颜色深于生品.[结论]该研究对于鉴别区分不同产地的甘遂和醋甘遂饮片具有一定的价值.  相似文献