互花米草厌氧发酵渣活性炭处理含镉废水的研究

采用静态吸附法,进行磷酸活化法不同剂料质量比(0.5～3.0)及活化温度(400～700℃)条件下制备的互花米草厌氧发酵渣活性炭对镉的吸附性能研究,考察不同初始浓度条件下活性炭对镉的平衡吸附量,旨在以吸附法治理含镉废水,探索吸附机理、影响因素、除镉吸附剂的最佳制备条件以及活性炭物化性质对镉吸附性能的影响.结果表明,镉的吸附性能与活性炭的制备条件有关,随着活化温度的升高,镉的吸附量逐渐增大,主要是因为高温条件下活性炭表面PO43-充当活性位点,促进镉的吸附.当剂料质量比为1.0,活化温度为700℃时,制备出的活性炭对镉的吸附性能最好,其最大吸附量可达38.91 mg·g-1,远远高于商业活性炭.镉的吸附量随着溶液初始浓度的增加而增大,吸附等温线符合Langmuir方程.溶液pH和活性炭表面化学性质是决定镉吸附量大小的决定性因素,当溶液pH在2～4时,各活性炭对镉的吸附能力随pH的增加而增加.本文为含镉废水的处理提供了一种低价高效的方法.     

Oxidative stress, steroid hormone concentrations and acetylcholinesterase activity in Oreochromis niloticus exposed to chlorpyrifos

We investigated the endocrine disrupting effects of chlorpyrifos-ethyl which is suspected to be originated from oxidative stress. Initially, the 96 h LC₅₀ values of chlorpyrifos in juvenile and adult of Oreochromis niloticus were determined to be 98.67 μg/L and 154.01 μg/L, respectively. Sub-lethal concentrations of chlorpyrifos-ethyl (5 ppb, 10 ppb, 15 ppb) were administrated to adult fish for 15 and 30 days. Fish were then left to depurate for 15 days in pesticide-free water. Gonadal somatic indices, serum sex steroids as indicators of reproductive function and cortisol level as indicator of stress condition were measured to observe the endocrine disruption effects of chlorpyrifos-ethyl. Gonadal glutathione S-transferase and antioxidant enzyme activities and lipid peroxidation as indicators of oxidative stress were also measured. Acetylcholinesterase activity was measured as a marker of chlorpyrifos toxicity. Results showed that serum estradiol, testosteron and cortisol levels in fish exposed to chlorpyrifos were lower than those of the control fish while gonad somatic indices did not change during the experiments. After 30 days, chlorpyrifos exposure decreased GST activity, and increased SOD enzyme activity by up to 215-446% compared with the control, suggesting there was a oxidative stress. No statistically significant differences between GPx and CAT specific activities, protein contents and lipid peroxidation were determined between control and treatment groups in all exposure concentrations and periods. Acetylcholinesterase activity decreased (45.83-77.28%) in gonad tissues. After recovery serum estradiol and testosteron levels were similar to those of the control levels. An increase in the GST and SOD enzyme activities were determined. Cortisol level and AChE activity in all exposure groups decreased after the depuration period, and fish were unable to overcome the stress of chlorpyrifos. Thus, this study revealed that after chlorpyrifos treatments there exists a protective function of antioxidant enzymes against lipid peroxidation in gonad tissue of O. niloticus. There also exist lower testosteron and estradiol levels in exposed fish than those of the control fish without any alterations in oxidative stress, which is attributed to the capability of chlorpyrifos to impair steroid hormone levels.     

交趾黄檀在西双版纳的引种生长表现及发展前景展望

交趾黄檀是著名的热带珍贵用材树种,其心材属上等红木,且具有重要的药用价值。文章系统阐述了交趾黄檀的经济价值和生物学、生态学特性。为获得2007年以来引种的该树种在西双版纳的适应性和生长表现,对勐腊县及景洪市五个引种种植点的交趾黄檀、树高、胸径、冠幅进行了调查和分析。结果表明,交趾黄檀在西双版纳州表现出较好的适应性,生长快速,病虫害少。藉此还分析了其在州内发展具有的气候、土地、政策、技术等优越条件。     

旱区坡耕地土壤层析水流动态模拟研究

水分是旱区坡耕地作物生长的关键因素。依据土壤水动力学和守恒原理,建立土壤层析水流模拟模型并开发成计算机模拟模型,采用洛阳旱区坡耕地长期定位试验数据对其进行了验证,模拟值与实测值误差绝对值控制约在10%以内,表明该模型可以应用于旱区坡耕地土壤水分的动态变化研究中。     

BA和GA3对华盛顿脐橙幼果^14C—光合产物调配的影响

华盛顿脐橙谢花后,用BA、GA_3和BA GA_3涂果,涂果后1-2周,引入~(14)CO_2标记光合产物,两年的研究表明,在第一次生理落果期间,各处理涂果后幼果中~(14)C-光合产物放射比强度大小为BA GA_3>BA>GA_3>CK。在第二次生理落果期间,各处理涂果后则为BA GA_3>GA_3>BA>CK。此结果与其分别减少第一和第二次生理落果的作用大小相一致。     

Pharmacokinetics of cefquinome in red‐eared slider turtles (Trachemys scripta elegans) after single intravenous and intramuscular injections

The purpose of this study was to evaluate the pharmacokinetics of cefquinome (CFQ ) following single intravenous (IV ) or intramuscular (IM ) injections of 2 mg/kg body weight in red‐eared slider turtles. Plasma concentrations of CFQ were determined by high‐performance liquid chromatography and analyzed using noncompartmental methods. The pharmacokinetic parameters following IV injection were as follows: elimination half‐life (t _1/2λz) 21.73 ± 4.95 hr, volume of distribution at steady‐state (V _dss) 0.37 ± 0.11 L/kg, area under the plasma concentration–time curve (AUC _0–∞) 163 ± 32 μg hr^?1 ml^?1, and total body clearance (Cl_T) 12.66 ± 2.51 ml hr^?1 kg^?1. The pharmacokinetic parameters after IM injection were as follows: peak plasma concentration (C _max) 3.94 ± 0.84 μg/ml, time to peak concentration (T _max) 3 hr, t _1/2λz 26.90 ± 4.33 hr, and AUC _0–∞ 145 ± 48 μg hr^?1 ml^?1. The bioavailability after IM injection was 88%. Data suggest that CFQ has a favorable pharmacokinetic profile with a long half‐life and a high bioavailability in red‐eared slider turtles. Further studies are needed to establish a multiple dosage regimen and evaluate clinical efficacy.     

砂姜黑土玉米根系生长发育动态研究

采取盆栽与大田试验相结合的方法, 研究了砂姜黑土玉米根系生长发育的动态变化。 结果表明： 玉米单株根系干重及活力在吐丝后15 d达到最大, 而后逐渐降低, 根系总长度及干重最大日增量在大喇叭口～吐丝阶段; 不同类型根系及不同层次节根长度、 干重和活力动态变化趋势不同, 层位愈高, 根系长度、 干重及活力愈大, 且     

坡面产沙BP神经网络模型研究

根据四川井研县坡耕地实验点对不同坡度、不同耕作方式情况下水土流失的实测资料 ,引入神经网络建模方法 ,建立了不同坡度下顺坡垄作和横坡垄作的次降雨产沙网络模型 ,得出前次降雨因子即前次降雨量、前次降雨强度及此两次降雨间隔天数对本次降雨产沙影响很大 ,不可忽略。针对复杂的非线性坡面产沙系统 ,BP网络模型比传统的回归模型能更好地刻画其本质特征。这不仅揭示了坡耕地水土流失的内在机理 ,同时为定量研究顺坡垄作改为横坡垄作的水土保持效益提供了科学依据。     

2000-2014年黄土高原植被叶面积指数时空变化特征

研究植被叶面积指数(LAI)时空变化特征,对植被的水土保持效具有重要意义.利用MOD15A2H遥感产品,基于Mann-Kendall趋势检验与Sen斜率分析方法,提取区域尺度与像素尺度上的植被LAI变化特征,并基于不同子流域、坡度、坡向及植被覆盖类型,对植被LAI的变化特征进行分析.基于MOD44B遥感产品,利用线性回归和偏相关系数,分析植被LAI的变化原因.结果表明:1)黄土高原2000-2014年,植被LAI呈显著增加趋势,其年绝对变化幅度为0.042,年相对变化程度为2.71％.2)空间上,在黄土高原58.6％的区域,LAI呈现显著增加趋势,仅有0.9％的区域LAI呈现显著减少趋势.植被LAI剧烈增加,主要发生在河口—龙门区间,包括皇甫川、窟野河、无定河和延河.植被在15°～35°的坡度上,LAI变化程度最剧烈,其变化在各坡向上没有显著差异,农田和草地的LAI变化程度最剧烈.3)与植被总覆盖度相比,植被垂直维结构与黄土高原植被LAI的变化更为相关,其中树木覆盖度的增加,是植被垂直维结构变化的重要原因之一.     

加勒比松杂交育种试验

在广东省遂溪、阳江和湛江3个地点对加勒比松杂种松的22个杂交组合进行了生长性状调查,其中遂溪和阳江的试验袜为13年生,湛江的试验林为11年生.用SAS软件对树高、胸径和材积进行了多重比较,筛选出生长性状好的杂交组合.结果表明:有多个杂交组合在生长性状上超过对照加勒比松古巴变种(Pinus caribaea Morele...