Estimating population dynamics without population data

We develop a biologically correct cost system for production systems facing invasive pests that allows the estimation of population dynamics without a priori knowledge of their true values. We apply that model to a data set for olive producers in Crete and derive from it predictions about the underlying population dynamics. Those dynamics are compared to information on population dynamics obtained from pest sampling with extremely favorable results.     

不同pH的柠檬酸对茶园土壤溶出液中氟组分变化的影响

通过连续流动搅拌法,研究了不同pH的柠檬酸对茶园土壤溶出液中氟组分变化的影响.结果表明,土壤溶出液的pH随溶出时间的延长而逐渐减小.土壤溶出液中的游离态氟和总氟的浓度随时间的延长和柠檬酸pH的升高而逐渐减小,且呈现初始(0—6h)溶出浓度较高,而后(6—10h)逐渐减缓的趋势.土壤氟的溶出过程用一级动力学方程、Elovich方程、扩散方程和双常数方程均有较好的拟合,决定系数(R2)均大于0.90.低pH(pH3.5)条件下,F主要以H-F形态存在,随着pH的升高(pH4.0—5.0),H-F形态的氟减小,Al-F络合态的氟增多,且随时间延长,溶出浓度均降低.反应开始的前1h,Al-F络合物主要以AlF3为主,占氟溶出总量的90%以上;至7h时,AlF+2的溶出量逐渐增大,并逐渐超过AlF3.低pH的柠檬酸促进土壤游离态氟和总氟的溶出,有利于络合态氟的形成,但对Al-F络合物的形态转化没有显著影响.     

三叶虫茶茶多酚提取工艺研究

研究萃取-沉淀法从虫茶中提取分离茶多酚的影响因素.采用单因素循环法考虑各影响因素,得出三叶虫茶茶多酚的最优提取工艺.用回流法提取茶多酚,并用单因素循环法分别考察提取剂、沉淀剂、转溶酸、萃取次数对茶多酚提取率的影响,用紫外-可见分光光度法对提取液进行检测.用萃取-沉淀法从虫茶中提取分离茶多酚,以80%丙酮作提取剂,Zn Cl2作沉淀剂,盐酸转溶的效果较为理想.结论表明,萃取-沉淀法提取分离虫茶中茶多酚,所需要的有机溶剂少,能耗低,纯度高,具有可行性.图4,表5,参14.     

吸烟烟气的细胞毒性作用和茶多酚保护作用的研究

以体外培养的中国仓鼠肺成纤维细胞V79为模型,用分光光度法和ESR自旋标记方法研究了吸烟烟气对细胞的损伤以及抗氧化剂茶多酚（GTP）的保护作用。结果表明,吸烟烟气能引发V79细胞膜的脂质过氧化,导致细胞死亡,使膜浅层的流动性增加,但对膜深层的动态性质没有明显改变。加入GTP后能抑制烟气引起的膜脂过氧化和膜流动性的改变以及细胞死亡,且这种抑制作用与GTP的浓度呈量效关系,而GTP本身对细胞膜浅层的流动性无明显作用,但对深层的流动性则有一定的影响。此外,还用马来酰亚胺自旋探针研究吸烟烟气对细胞膜膜蛋白巯基结合位点局部构象的影响,结果发现,随着烟气作用增强,ESR波谱的强弱固定化比值（S/W）增大,表明膜蛋白上巯基结合位点处结构变得紧密,这说明吸烟烟气改变了膜蛋白的构象,GTP本身在高浓度（＞0.1mg/mL）时也能使S/W增大,当低浓度（＜0.05mg/mL）则没有影响。当GTP浓度为0.01mg/mL时就可以抑制烟气引起的S/W的增大。     

Energy Analysis of Sugarcane Production in Morocco

An energy analysis of sugarcane production in small and large farms was made in Morocco. Total energy expenditures were 64.90 and 47.83 GJ/ha and energy outputs were 100.80 and 85.80 GJ/ha in large and small farms, respectively. The output/input energy ratios were 1.6 and 1.8. The energy intensity lies between 0.7 and 0.8 MJ/kg and is one of the highest among sugarcane producing countries. Irrigation is the most energy consuming operation with about 50% of total energy inputs. Electricity, fertilizers, fuel, and machinery are the main energy inputs. The influence of the different inputs is discussed and practical measures for energy saving and environmental conservation based on energy analysis are discussed.     

Veterinary drugs in groundwater in a dairy region of central Argentina and risk assessment for human health

Veterinary drugs used in dairy production are potential contaminants of surface or groundwater sources, being able to affect human and environmental health. It is known that chronic exposure to antibiotics in low concentrations present in water can generate microbial resistance. This study aimed to evaluate the presence of veterinary drugs in 53 groundwater samples used for animal and human consumption, collected in dairy milking parlors, in an important milk-producing area of central Argentina, and to assess the risk to human health when they are used as drinking water. In 75% of the total samples analyzed, at least one veterinary drug was detected. The most frequently found drugs in water samples were the antibiotics tetracycline in 58.5% and oxytetracycline in 56.6%, and an anti-inflammatory, flunixin in 39.6%. In the water samples, the tetracycline and oxytetracycline concentrations were between 0.1 and 5.3 μg/L and flunixin concentrations were between 0.01 and 2.1 μg/L. The frequency of appearance and the concentration levels of the substances found in the water samples were evaluated according to the productivity, size, and production system (confined or pasture) of the dairy farms. Higher concentrations and proportions of water samples containing antibiotics were observed when the number of animals per dairy farm was >182 and when the productivity was high (>25 liters per animal per day). In the case of flunixin, the percentage of detection was similar in all evaluated categories. The risk assessment for children and adults, considering the intake of drinking water containing residues of these drugs, did not indicate a significant health risk. It would be advisable to evaluate other sources of drinking water, both surface and underground, in other regions of the country, to provide data to assess the impact of these substances and the other contaminants on environmental and human health.     

超声辅助乳化液相微萃取分析绿茶饮料和番茄汁中有机磷农药残留

农药施用于田间,必然会残留于环境中。农药残留的分析方法多种多样。为探究灵敏度高、重现性好的样品前处理方法,建立了超声辅助乳化液相微萃取,结合气相色谱和火焰光度检测器测定绿茶饮料和番茄汁中5种有机磷农药的方法,对萃取条件进行了优化,如萃取溶剂种类和体积、超声频率和时间、盐效应。在优化后的萃取条件下,5种有机磷农药实现良好分离,空白添加实验结果表明在0.1~10μg·L-1之间,线性相关系数在0.9985~0.9994之间,检测限在0.005~0.020μg·L-1之间,相对标准偏差(n=5)在4.3%~9.4%之间。在绿茶饮料和番茄汁实际样本检测中,目标分析物含量均低于检出限。样本添加回收试验的回收率均大于88.5%,相对标准偏差(n=3)在2.2%~9.8%之间,结果表明该方法用于液体样本中农药残留检测真实可靠。     

屯绿陈茶有效成分提取及茶多酚提纯工艺研究

探讨了从陈茶中提取有效成分和茶多酚的提纯工艺。采用不同物料比、浸提温度、浸提时间的正交实验,通过热水煮提从茶叶中获取水溶性物质。结果表明,当料液比为1：20、90℃、120min时,测得的水提取物固化物量最多可达31％;茶叶水提物固化物、水配比为13：400时与乙酸乙酯萃取茶多酚的得率达23％,茶多糖从总量中提取的得率达2．5％。屯绿陈茶有效成分保留效果良好,具有较好的综合利用价值。     

Dissipation of carbofuran and carbaryl on Oolong tea during tea bushes,manufacturing and roasting processes

Carbofuran (2,3-dihydro-2,2-dimethyl-7-benzofuranol-N-methylcarbamate) and carbaryl (1-naphthyl-N-methylcarbamate) are insecticides widely used in tea plantations. The objective of the present study was to evaluate the dissipation of carbofuran and carbaryl during the growth periods of Oolong tea, processing and roasting. Analysis of the residual insecticides was carried out using high-pressure liquid chromatography with a post-column fluorescence detector. Results showed that in the tea field carbofuran dissipated faster then carbaryl. Manufacturing processes of Oolong tea further reduced the carbofuran and carbaryl contents. The persistence of carbofuran and carbaryl was decreased with increasing roasting temperature. From the results, we conclude that the presence of carbofuran and carbaryl in tea can be reduced by proper field management, manufacturing and roasting processes.     

多酚原位固化茶渣对水中Cr（Ⅵ）的吸附

通过甲醛与茶渣中多酚类组分的反应制备了多酚原位固化茶渣吸附材料,并将其用于对水中Cr（Ⅵ）的吸附。表征结果显示：茶渣多酚的原位固化提高了其热稳定性,同时对茶渣粒料起到了修补增强作用。固化茶渣对Cr（Ⅵ）的吸附量随溶液pH的减小而增大。在吸附温度303 K、初始Cr（Ⅵ）质量浓度60 mg/L、吸附剂投加量1.0 g/L、吸附时间300 min、溶液pH为2的条件下,固化茶渣对Cr（Ⅵ）的吸附量为56.56 mg/g,去除率达94.3%。固化茶渣对Cr（Ⅵ）的吸附符合Langmuir等温吸附模型和准二级动力学方程,吸附是一个自发的、吸热过程,303,318,333 K下的Langmuir饱和吸附量分别为83.26,107.64,129.20 mg/g。