环境管制政策的实施效果评价——以九龙江流域"限猪令"为例

环境管制一直是我国环境污染治理所采取的主要政策之一,对我国的环境保护起到了一定的积极作用,同时也存在一些弊端,致使其成效不甚显著甚至背离初始目标.在此情况下,如何评价环境管制政策绩效具有重要的理论和实际意义.本文以九龙江流域"限猪令"政策为例,选取政策目标实现度、主要环保指标实现、环保投入效益、公众参与及满意度四个方面...     

Assessment of Uterine Vascular Perfusion During the Estrous Cycle of Mares in Connection to Circulating Leptin and Nitric Oxide Concentrations

The objective of this study was to find difference in vascular perfusion of uterine horns or uterine body throughout the estrous cycle and their relation to circulating nitric oxide and leptin concentrations. Five cyclic mares were subjected to transrectal Doppler ultrasonography and blood sampling for 18 days. Area of color and power Doppler modes was measured in pixels. Day (P = .0001) of the estrous cycle and ovulation (P = .0001) influenced uterine blood flow. Uterine body blood flow directed away from the transducer (blue, P = .0001) increased from day −5 until day 0 (day of ovulation), and its power (P = .0001) blood flow increased from day −6 until day 0; then, both decreased until days 12 and 10, respectively. Conversely to the contralateral uterine horn, ipsilateral uterine horn blood flow directed away from the transducer (blue, P = .0001) increased from day −5 until day −1, and its power (P = .0001) blood flow increased from day −6 until day 0; then, both decreased until day 10. Nitric oxide concentrations (P = .0001) attained two major peaks; the first on day −3 and the other persisted from day 2 until day 5. Leptin concentrations increased (P > .001) with a maximum value on day 0 and then decreased until a minimum value on day 9. In conclusion, during the estrous cycle, ipsilateral uterine horn and uterine body blood vessels had similar blood flow. Both leptin and nitric oxide played a role during follicle growth, ovulation, and corpus luteum development and modulated uterine blood flow before and after ovulation.     

乡村振兴战略背景下农村坑塘治理分析研究——以河南睢县实地调查为例

针对农村坑塘"无人治、没钱治、无人管、散乱难治"等方面的难题,以乡村振兴战略为思想指导,结合河长制工作重点,根据农村坑塘高效治理工作对打造生态宜居环境、创建乡风文明、促进产业兴旺、实现农民富裕的重要性。在此基础上,以河南省睢县农村坑塘为例,以全面推行河湖长制促进乡村振兴为目标,把小微水体整治与乡村振兴等工作有机结合,进行水岸同治。按照远村塘、近村塘的分类,提出相应建设模式,并提出农村坑塘建设建议;另外,从"人治"和"法治"两个方面进行"人治巩固基础,法治加深层次"管护模式,为黄淮地区农村坑塘治理提供多种路径,助力乡村振兴。     

基于SPEI_PM指数的渭河流域气象干旱时空演变特征

利用渭河流域25个气象站点1980−2018年月值气象数据集，基于Penman-Monteith蒸散模型计算多个时间尺度的标准化降水蒸散发指数（SPEI），分析渭河流域气象干旱的演变、趋势、影响范围、发生频率和持续时间等时空变化特征，以期为渭河流域防灾减灾管理提供科学依据。结果表明：（1）近39a来渭河流域有明显的干湿周期变化，但整体上呈变干的趋势，干旱时段主要集中在1995−2009年，其中以2000−2009年的干旱站次比最大，平均达到36%，且干旱持续时间最长，约3.6个月，1980−1989年干旱持续时间最短，约1.6个月；（2）渭河流域秋季总体呈湿润变化趋势，而春季和夏季干旱在不断加剧，是区域年际干旱的主要驱动力；（3）渭河流域干旱以危害性较小的轻中旱为主，但2000年前后出现严重及极端干旱的站次相对较多，其中1997年研究区内发生的干旱程度较高，影响范围较广；（4）不同时间尺度各等级干旱发生频率的变化规律表现一致，均呈现出干旱等级越高发生频率越低的态势，且极端干旱在年际尺度内发生次数较为频繁，从空间上看渭河流域东北部是干旱多发区。总之，近39a来渭河流域总体干旱较为严重的时段为2000−2009年，且研究区内干旱呈北重南轻特征，因此北部地区仍需加强防灾管理。     

The Standardization of an Apparatus for the Mixing of Soil Samples for Nematode Extractions

Quantitative determination of nematode populations in soils frequently necessitates the mixing of representative soil samples to form a homogeneous, compound sample from which the nematodes are extracted. A mixing apparatus was developed and standardized with the aid of a spectrophotometric technique by which the dispersion of a dye through the soil during mixing could be determined. It was found that the mixer is most suitable for use on sandy loam soils. Optimal mixing is obtained at a speed of 15 rpm for 2 minutes. Under these conditions mechanical damage to nematodes during mixing is minimal.     

珠江三角洲地区生鲜农产品冷链网络化运输技术

文章主要是对我国的珠江三角洲地区的生鲜农产品冷链的物流方式进行探究,结合现在我国的生鲜农产品冷链运输技术的现状和发展前景进行大胆的预测,并提出我国的珠江三角洲地区的生鲜农产品冷链的运输技术的网络化的建议。     

高效节水灌溉管道流量计算原则初探

对于管网优化及投资分析来说,最不利情况下的水力条件不是普遍条件,不能够完全代表管网应当有的优化假定条件。通过管道控制灌溉面积来确定管道的流量,按照满足在一天内,管道控制的所有灌水器都灌溉一次的原则确定,并给出公式。让管道的流量这一重要参数,在高效节水灌溉工程优化和设计计算中变得简单并容易计算。     

水头可调薄壁堰式渠道流量智能测控系统优化试验研究

采用巴赞堰流公式计算流量的水头可调薄壁堰式渠道流量智能测控系统通过渠道流量量测与控制试验,验证了其精准的测流功能和智能控制技术的可行性。为进一步提高该测控系统运行的效率和稳定性,减少运行能耗,对矩形薄壁堰堰流公式进行水力试验研究,通过分析堰上水头和流量关系,拟合出矩形薄壁堰流量计算公式。通过向该拟合公式引入修正系数λ=0.848,将测控系统测得的堰上水头数据值代入该拟合公式求得的流量值与电磁流量计测得流量值的差值的平均值为-0.004L/s,标准差为0.119,线性相关系数R2=0.989 1。该拟合公式相对于巴赞堰流公式形式简单、参数较少、运算简便,同时也满足节水灌溉对精准测流的要求,更适用于水头可调薄壁堰式渠道流量智能测控系统,对于在灌区推广和使用该测控系统具有重要的意义。     

The Fluorescent Characterization and Analysis of Two Brucella Attenuated Vaccine Infecting Mouse Macrophagocyte

The experiment was conducted to discuss the difference of binding time of green fluorescent protein B.melitensis M5 (GFP-M5) and B.abortus S19 (GFP-S19) infecting the mouse macrophagocyte (RAW264.7),lysosome,endoplasmic reticulum and golgi body in the initial stage and compare the binding rate of GFP-M5,GFP-S19 with organelle in different timeline,respectively,by confocal laser scanning microscope (CLSM) and flow cytometry.The result showed that GFP-M5 and GFP-S19 were successfully constructed.The intracellular survival ability of Brucella M5,Brucella S19,GFP-M5 and GFP-S19 were not obvisouly affected after infecting RAW264.7.GFP-M5 and GFP-S19 could enter the macrophagocyte in 30 mins,and in 2 h the Brucella could reach lysosome,endoplasmic reticulum and golgi body.In addition,the binding time for two attenuated vaccine did not show differences in 1,2,3 and 4 h.The content of GFP⁺ cell produced by RAW264.7 infected by GFP-M5 and GFP-S19 did not show significant differences (P>0.05).Therefore,the two strains did not have significant differences in the invasion ability in the initial stage of infecting host cell.