European eel distribution and body condition in a river floodplain: effect of longitudinal and lateral connectivity

Abstract – We studied eel population characteristics (size classes, densities and body condition) in the lower Loire River floodplain (France) to evaluate the effects of longitudinal and lateral gradients. A total of 36 sites were electrofished in June 2005. The sites were grouped first into three river segments according to the distance inland corresponding to a longitudinal gradient and secondly into three lateral connectivity categories. Results indicate that small eels, especially those ≤300 mm, were very abundant downstream but density rapidly decreased upstream. In addition, eels ≤150 mm tended to be most abundant in connected waterbodies. Conversely, the distribution of larger eels was quite uniform across both dimensions. Eel condition decreased upstream. In parallel, in downstream river segment, eels had a lower condition in disconnected waterbodies than in connected ones. Eel specialists still have only a longitudinal perception of eel habitat. Our results suggest that lateral gradients should be also taken into consideration.     

The whole amino acid profile as indicator of the nutritional condition in cultured marine fish larvae

The effect of variations in the amount or quality of food provided on the amino acid profile of larvae, was tested in two marine fish species, the Senegal sole (Solea senegalensis) and the sea bass (Dicentrarchus labrax). The objective was to assess whether such nutritionally suboptimum dietary patterns, which simulate situations that may occur in hatcheries, result in variations in the concentration of one or more amino acids that could be used as indicators of nutritional condition of larvae. Restriction in the normal food ration by 60% had no clear effect on the amino acid profile of sea bass, while the concentration of some amino acids (Arg, Ala and Phe) showed significant variations in sole. Feeding on artificial diets, which have shown their inadequacy a priori, resulted also in no significant effect on the profile of sea bass, but in a dramatic modification of the amino acid profile in sole. In addition, changes in the amino acid profiles considered as a whole were evaluated using the cluster analysis instead of paired comparisons between amino acid concentrations in each treatment. The analysis clearly separated profiles of larvae fed restrictedly or inadequately from their controls, irrespective of the species. This demonstrated the potential value of evaluating whole changes in amino acid profile as nutritional indicator. Besides, it was demonstrated that sensitivity of larvae to nutritional changes that may be reflected in the amino acid profile is greatly conditioned by the species and developmental stage.     

基于特征线方程N—S方程非增量型分离算法

为克服传统有限元方法求解流场时由于对流项占优而引起的求解振荡和基函数选择困难的问题,推导了基于特征线方程的粘性不可压N-S方程的增量型和非增量型分离算法的公式及求解步骤,并讨论了两者的Babuska-Brezzi条件.沿着特征线方向,N-S方程的对流项消失,方程矩阵是自伴随矩阵,可以自动满足有限单元法中能量泛函最小的要求,并可以给出合理的粘性耗散项.动量方程的求解采用非增量型分离算法,压力和速度可以采用任意阶次的插值函数,离散后的方程自动满足Babuska-Brezzi条件.为验证算法的可靠性,采用T3P3空间等阶次U-p单元计算了方柱绕流.结果表明：基于特征线方程的非增量型分离算法可以很好地应用于粘性不可压流场的计算,与目前流行的其它方法相比,该算法有明显的优势.     

高原型牦母牛生产周期中体况评分变化监测

对240头牦母牛进行为期一年的体况评分监测,发现牦母牛体况变化与草地饲草的供给状况相一致,牦母牛体况变化基本规律为暖季表现为快速上膘,冷季呈现逐步消耗。体况评分最低的时期为5~6月份,最高在10月和11月份。体况消长变化呈现两年一周期的模式。     

浅析农村人力资源开发的现实条件构建路径

阐述了我国农村人力资源开发的现实意义,从农村自然、人文、经济和制度环境条件探讨了农村人力资源开发的构建路径。     

白蜡杆软化和防蛀技术研究

白蜡(Fraxinus chinenesis)为木犀科(Oleaceae)白蜡树属(Fraxinus)的树种,落叶乔木或灌木。主要分布在西南、华中、华东、华北等地区。因白蜡杆木材具有材色浅、结构细、纹理直、软硬度适中、韧性好、可任意造型等优点,广泛用于农具、家具,特别适于弯曲部件、工艺品和文休用品的制作。自90年以来,以蜡杆、蜡条为主要原料生产高档工艺家俱的工作已经起步,但由于生产过程中缺乏合理实用的软化工艺及设备、防蛀工艺及设备,关键技术缺乏研究,不仅生产效率低,产品的内在质量无法改善,而且残次品率高,虫蛀率也高达80%以上。该研究提出了以蒸汽软化处理工艺、负压浸注防蛀工艺技术,既有效的软化了白蜡杆,同时达到了防蛀要求,产品的内在质量得到了改善。     

Watershed Health Characterization Using Reliability–Resilience–Vulnerability Conceptual Framework Based on Hydrological Responses

An attempt was made to employ the reliability (R_el)–resilience (R_es)–vulnerability (V_ul) conceptual framework to develop a typical indicator system for quantitative assessment of watershed health. The study aimed to conceptualize and customize the R_elR_esV_ul framework to watershed health assessment for the Shazand Watershed in Markazi Province, Iran, for the period of 1977–2014. To this end, four easily, reliable, available and accessible criteria viz. standardized precipitation index (SPI), low and high flow discharges (LFD and HFD), and suspended sediment concentration (SSC) were selected, and corresponding indices for reliability–resilience–vulnerability (R_elR_esV_ul) framework were accordingly conceptualized and calculated. The thresholds of 0.1, 0.16 m³ s⁻¹, 12.63 m³ s⁻¹ and 25 mg l⁻¹ day⁻¹ were thus selected for SPI, LFD, HFD and SSC, respectively. The results showed a decreasing trend in R_el and R_es, and an increasing trend in V_ul for SPI and LFD in the Shazand Watershed. The results further showed an increasing trend in R_el, and a decreasing trend in V_ul for HFD and SSC. A decreasing trend was ultimately recognized in watershed health index for all criteria except SSC. Additionally, the integrated hydrological watershed health index of 0.16 ± 0.11 obtained from the geometric mean of the R_elR_esV_ul framework indices also showed a decreasing trend for the Shazand Watershed health during the study period. The results of the present initiative study can be considered as a baseline by decision makers and managers to effectively adjust watershed management strategies to handle land degradation issues in the area. Copyright © 2016 John Wiley & Sons, Ltd.     

大气环流指数和地面气象要素对海南省橡胶树白粉病的影响

为探讨大气环流指数和地面气象要素对海南省橡胶树白粉病病情指数的影响,利用1962—2009年逐月大气环流指数和逐日地面气象要素资料,根据橡胶树白粉病病情指数等级,结合因子膨化、相关分析和多元回归等方法,筛选影响橡胶树白粉病病情指数的大气环流指数和地面气象要素,构建等级指标,建立预测模型,并对模型进行检验。结果显示:影响橡胶树白粉病病情指数的大气环流指数依次为北半球副高面积指数、北半球副高强度指数、西太平洋副高西伸脊点、北美区极涡面积指数、亚洲区极涡强度指数和印缅槽,显著影响时段为上年7月至当年4月;地面气象要素有平均最高气温、相对湿度、平均气温≥20℃的日数、小雨日数和平均风速,显著影响时段为上年10月至当年1月;基于大气环流指数、地面气象要素、大气环流与地面气象综合因子的橡胶树白粉病病情指数预测模型准确率分别为74.3%～78.8%、74.7%、94.6%～98.3%,表明基于大气环流和地面气象综合因子的模型准确率较高,可作为海南省橡胶树白粉病的中长期预测模型。     

白腐菌降解玉米秸秆条件的优化试验

针对白腐菌对木质素的独特降解能力和玉米秸秆在制取燃料乙醇方面的应用,对白腐菌降解玉米秸秆的降解条件进行优化,通过正交实验得出较好的发酵培养基的组成:玉米秸秆为5g,酒石酸铵为1 g/L,pH值为4.5,微量元素的体积为15mL, VB1的质量为100ug, 吐温80的质量浓度为0.01%,最佳诱导剂是二甲苯胺,表面活性剂是吐温80,最佳通气状况是用4层纱布封口.     

贮藏条件对郁金香花粉生命力的影响

以花粉萌发率为指标,研究了6种贮藏条件对4个品种的郁金香花粉生命力的影响.结果表明:不同品种的郁金香花粉生命力不同.贮藏温度对郁金香花粉生命力有很大影响,-18℃ 冷冻条件有利于保持郁金香花粉生命力,0～2℃冷藏条件次之,20～25℃常温条件最差.贮藏湿度对郁金香花粉也有影响,在常温和冷藏条件下,干燥条件比非干燥条件更有利于郁金香花粉生命力的保持.