区域建设用地动态变化及经济效益评价——以天水市为例   总被引：1，自引：1，他引：0  

胡永琴  邸利王乐 张倩 《中国农学通报》2013,29(17):96-100

随着工业化和城市化的快速发展,对建设用地的需求量也越来越大。为了深入了解建设用地利用情况及经济效益,缓解目前土地利用的供需矛盾。基于2000—2009年的天水市建设用地数据和社会经济的相关数据,运用灰色关联度分析天水市建设用地动态变化和驱动因子,并选取与建设用地相关的指标因子,利用变异系数法对天水市建设用地的经济效益进行分析评价。结果表明：2000—2009年,天水市建设用地增长明显,影响天水市建设用地增长的主要驱动因子为总人口数、GDP和第二、三产业产值以及客运量;同时建设用地经济效益也呈逐年增长的趋势。通过对各因素影响程度的分析,为有效利用土地资源、提高土地利用经济效益提供参考。  相似文献   

低磷胁迫对巴西橡胶树幼苗若干生理代谢指标的影响   总被引：4，自引：0，他引：4  

何鹏  王大鹏  韦家少  吴敏  吴炳孙  高乐  覃怀德 《热带作物学报》2012,33(11):1976-1979

通过水培试验,研究31(CK)、10、5、1、0 mg/L不同低磷胁迫水平对巴西橡胶树幼苗生理代谢的影响。结果表明:橡胶树各器官中的可溶性糖含量(SSC),随着磷浓度的降低而降低;可溶性蛋白含量(SPC),则随着磷浓度的降低,在稳定叶和根中升高,在嫩叶和茎中降低;叶绿素含量,随着磷浓度下降而升高;根活力和根硝酸还原酶活性,均随着磷浓度下降而下降。  相似文献   

园林废弃物堆肥替代泥炭用于天竺葵和金盏菊栽培   总被引：2，自引：0，他引：2       下载免费PDF全文

魏乐  李素艳  李燕  龚小强  孙向阳 《浙江农林大学学报》2016,33(5):849-854

为探索园林废弃物堆肥替代泥炭用于天竺葵Pelargonium zonale和金盏菊Calendula officinalise栽培基质的可能性,将改良后的园林废弃物堆肥分别以0%,25%,50%,75%和100%的比例替代泥炭进行试验。将天竺葵和金盏菊的种子分别播种在不同基质中进行育苗研究,当幼苗生长35 d后进行测定。将幼苗分别移栽到不同基质中,栽培6个月后进行测定。结果表明:随园林废弃物比例的增加,基质的容重增加,总孔隙度度、通气孔隙度和持水孔隙度呈下降趋势。园林废弃物比例的增加提高了基质pH值、电导率值、大量元素和微量元素质量分数。育苗试验显示:天竺葵幼苗在园林废弃物处理中的生长量显著（P < 0.05）低于对照组,即使在25%的低比例下也会对幼苗产生不良影响。金盏菊幼苗在添加25%和50%的园林废弃物处理中的生长量与对照组一致。盆栽试验显示:添加园林废弃物显著（P < 0.05）增加了天竺葵和金盏菊的地上部分干质量、株高、茎直径和叶面积以及金盏菊的根干质量和花蕾数。园林废弃物堆肥可以部分代替泥炭作为金盏菊育苗基质及天竺葵和金盏菊的栽培基质。表 5 参15  相似文献   

灰质异位的临床病理学特征研究          下载免费PDF全文

冷慧  付静  梁乐  刘瑛 《勤云标准版测试》2016,36(6):29-32

目的 探讨灰质异位病理学诊断的客观依据。方法 分析17例灰质异位手术切除标本病理及临床资料,辅以免疫组化方法,计数灰质异位灶中神经元的数量和类型。结果 本组病例中灰质异位术前MRI确诊为3例,其余14例（82.4%,14/17）均依靠镜下诊断。大体改变有三型：（1）白质中孤立的皮质样结节;（2）位于皮质下、呈结节状或舌状与皮质相连;（3）大脑皮层增厚,皮白质分界不清。镜下部分灰质异位结节边界清,结节中神经元排列紊乱,无极向,无正常皮质分层结构;神经元可表现退变、坏死、形态不成熟;免疫组化GFAP可显示部分灰质异位结节的轮廓,神经元核抗原（neuronal nuclei,NeuN）、微管相关蛋白2,（microtubule associated protein-2,MAP-2）染色显示神经元数量减少且其中不成熟神经元比例增高,差异有显著统计学意义（t=-3.66,P<0.01）。结论 灰质异位病变范围广泛时可于影像学检测中发现,但多数的灰质异位诊断仍需依靠病理组织学确诊,免疫组化GFAP有利于观察灰质异位灶形态,NeuN和Map-2强阳性细胞计数能为灰质异位诊断提供客观依据。  相似文献   

Review of the technical challenges facing aquaculture of the European abalone Haliotis tuberculata in Ireland     

Colin Hannon  Rick A. Officer  Jean Le Dorven 《Aquaculture International》2013,21(2):243-254

Insufficient supply of available market size abalone from the wild stocks has resulted in increasing efforts since the early 1990s to culture this valuable marine shellfish. Despite significant financial investment and the establishment and expansion of farms around Europe, the production of a saleable end product has remained undefined. The technical barriers to producing viable juvenile abalone spat still impair growth of the industry in Ireland. Critical developments required in the industry are identified. Uptake of these developments from research remains slow due to the trial-and-error approach taken by operators. Using technologies and procedures from producing countries and implementing them into Irish culture conditions will aid the development and expansion of the industry.  相似文献   

银鲳渤海湾群体形态特征统计分析     

蒋艳玲  徐海龙  乔秀亭  吴乐 《河北渔业》2013,(12):10-14

对天津汉沽区海域渔获物银鲳的形态学性状进行测量分析。结果表明:全长/体长为1.45±0.04,体高/体长为0.54±0.03,头长/体长为0.24±0.01,尾柄高/体长为0.09±0.006,眼间距/体长为0.10±0.006,眼径/体长为0.08±0.005,肠长比为2.81±0.33。背鳍43⁴8、尾鳍2248、尾鳍22³6,胸鳍2036,胸鳍20³3,臀鳍4233,臀鳍42⁴9、鳃耙1949、鳃耙19²4,幽门盲囊16924,幽门盲囊169²72,椎骨31272,椎骨31³7。当样本个体大小处于同一水平时,以身体主要部分的比例特点为依据难以进行性别区分,可数性状亦不能作为性别区分的可靠依据。另外,不同地理群体样本的可数性状差异与生长阶段和环境因素均有关系。  相似文献   

Effects of feeding rates on the growth,water quality and nutrient budget of western king prawn (Penaeus latisulcatus Kishinouye) reared in recirculating aquaculture systems     

Van Khoi Le  Ravi Fotedar  Martin S Kumar 《Aquaculture Research》2013,44(7):1110-1119

Feed rate is one of the important variables considered for the improvement in production of prawns. The effects of four feeding rates on growth, water quality and the nutrient budget of Penaeus latisulcatus were investigated for 98 days. The specific growth rate (SGR) at 3.0% feed rate was significantly higher than at all higher feed rates, and there was no significant difference in SGR between 4.5%, 6% and 7.5%. Total ammonia nitrogen concentrations in all treatments remained low in the safe range for prawn culture. Dissolved inorganic nitrogen and nitrate nitrogen were significantly higher (P < 0.05) in prawn tanks received feed rates of 6.0% and 7.5%. Total phosphorus and the soluble reactive phosphorus linearly increased with the progression of the trial and feeding rates. Nutrient conversion rates were significantly higher (P < 0.05) in prawns receiving the feeding rate of 3.0% than feeding rates of 6.0% and 7.5%. The lowest food conversion ratio was recorded at feeding rates of 3% and 4.5%. Nutrient budget showed that 6.01–15.99% nitrogen and 4.53–9.29% phosphorus of the nutrient inputs were retained in the prawn biomass. The results indicated that the growth and nutrient conversion rate may not increase with the increase above 3.0% of biomass per day.  相似文献   

Evaluation of potential feed sources,and technical and economic considerations of small‐scale commercial striped catfish (Pangasius hypothalamus) pond farming systems in the Mekong Delta of Vietnam     

Chau T Da  Le T Hung  Håkan Berg  Jan E Lindberg  Torbjörn Lundh 《Aquaculture Research》2013,44(3):427-438

A technical and socio‐economic survey was conducted in Dong Thap, Can Tho and An Giang, provinces of Vietnam in 2009. The results showed that most of the small scale farmers of striped catfish (Pangasius hypothalamus) carry out fish pond culture, developed and operated by self‐learned experience and from neighbours knowledge. The mean pond depth varied from 3.5 to 4.0 m, ranging from 2 to 6 m. Most of the fish farms have extremely high stocking density, with an average of about 40 fish m^?2, in some cases up to 70 fish per m². The average yields and net income of small‐scales pond farming is about 21–27 kg per m² crop^?1 and US$ 0.184–0.329 kg^?1 crop^?1 respectively. These figures are not significantly different compared with large‐scale pond farming. About 75%, 86% and 80% of fish farmers in Dong Thap, Can Tho and An Giang province, respectively, received positive net returns. Farm‐made feed is still playing an important role because of higher net profit compared with commercial pellet feeds. Rice bran and trash fish are the main feed ingredients for farm‐made feed formulations. Striped catfish farmers are now actively searching for locally produced plant protein sources as alternatives to marine trash fish or fish meal.  相似文献   

GOVERNING THE ENVIRONMENTAL AND SOCIAL DIMENSIONS OF PANGASIUS PRODUCTION IN VIETNAM: A REVIEW∗     

Simon R. Bush  Nguyen Tri Khiem  Le Xuan Sinh 《Aquaculture Economics & Management (Blackwell Science)》2013,17(4):271-293

The Vietnamese government's policies for an export-led economy have supported the rapid growth of Pangasius production but have had limited success in mitigating the environmental and social impacts stemming from unplanned and ad hoc expansion. Recognising the poor performance of state regulation the industry and government have turned to private or market-based environmental and social standards for Pangasius production. The success of these private governance arrangements is dependent on the capacity of producers to comply with standards within their wider environmental, social, cultural and economic context. This paper reviews current concerns over the sustainability of Pangasius production and draws attention to the challenges private governance initiatives face in steering towards sustainable production.  相似文献   

VALUE CHAIN OF SNAKEHEAD FISH IN THE LOWER MEKONG BASIN OF CAMBODIA AND VIETNAM     

Le Xuan Sinh  Hap Navy 《Aquaculture Economics & Management (Blackwell Science)》2013,17(1):76-96

Snakehead fish are the most preferred fish species for food in Cambodia and Vietnam, and are consumed in both fresh and processed forms. The purpose of this paper is to describe the value chains of captured and cultured snakeheads in the Lower Mekong Basin (LMB). The important actors involved in the value chain of snakeheads in the LMB of Cambodia and Vietnam were fishers, fish farmers, wholesalers, retailers, and processors. The value chain of wild captured snakeheads in Cambodia was focused on 11 marketing channels, and for cultured snakeheads in Vietnam, 10 market channels. The distribution of benefits among the chain actors was unequal, with the highest proportion of profit going to wholesalers in Cambodia and collectors in Vietnam. In order to develop the value chain of snakehead for the long-term in the LMB, appropriate plans must be prepared for each country in association with better management and protection of natural aquatic resources.  相似文献