Development of a terrestrial vertebrate model for assessing bioavailability of cadmium in the fence lizard (Sceloporus undulatus) and in ovo effects on hatchling size and thyroid function

In the terrestrial environment, standardized protocols are available for measuring the exposure and effects of contaminants to invertebrates, but none currently exist for vertebrates. In an effort to address this, we proposed that developing lizard embryos may be used as a terrestrial vertebrate model. Lizard eggs may be particularly susceptible to soil contamination and in ovo exposure may affect hatchling size, mortality, as well as thyroid function. Toxicant-induced perturbations of thyroid function resulting from in ovo chemical exposure may result in toxicity during the critical perinatal period in reptiles. Fertilized Eastern fence lizard (Sceloporus undulatus) eggs were placed in cadmium (Cd)-spiked expanded perlite (0, 1.48, 14.8, 148, 1480, 14 800 μg Cd/g, nominal concentrations), artificially incubated at 28 °C, and examined daily for mortality. Whole lizard hatchlings as well as failed hatches were homogenized in ethanol and the homogenate was divided for Cd body residue analysis and thyroid hormone (triiodothyronine (T₃) and thyroxine (T₄)) analyses. Acute mortality was observed in the two highest doses (1480 and 14 800 μg Cd/g). Cadmium body residues showed a higher internal concentration with increasing exposure concentration indicating uptake of Cd. There was a decrease in T₃:T₄ ratio at the highest surviving dose (148 μg Cd/g), however, there were no differences observed in hatchling size measured as weight and snout-vent length, or in whole body thyroid hormone levels. In summary, this study has shown Cd amended to a solid phase representing soil (perlite) can traverse the thin, parchment-like shell membrane of the fence lizard egg and bioaccumulate in lizard embryos. We believe this study is a good first step in investigating and evaluating this species for use as a model.     

两段接触氧化法处理生活污水的实验研究

接触氧化法具有处理效率高，耐冲击负荷，活污水的模拟实验基础上，探讨了水力停留时间、供气量力停留时间均为1h时，COD、BOD，和SS的平均去除率氧化法对氨氮有较好的去除效果。工程实例运行情况表镇生活小区的生活污水处理。水水质好，占地面积小等特点。本文在两段接触氧化法处理生处理效果的影响。实验结果表明：在总气水比为5：1，两段的水别达到94．5％、93．2％和91．7％。与活性污泥法相比，两段接触，出水水质符合国家污水排放标准，该法也适用于厂矿企业及城镇生活小区的生活污水处理。     

Assessing water quality in a tropical lake using biomarkers in zebrafish embryos: developmental toxicity and stress protein responses

In order to achieve a more substantial appraisal of lake water quality, the assessment must not be based only on chemical measurements and analyses of the water itself, but even more so on the impact of existing conditions on aquatic biota. This is possible with the use of biotests or biomarkers, e.g. investigations of the developmental parameters (96-h embryotoxicity evaluate) or of the induction of heat shock proteins (proteotoxicity evaluate). To evaluate the suitability of these tests for environmental screening, fertilized zebrafish eggs were exposed to water samples collected from five sites of varying levels of stress from Laguna Lake, Philippines. Reconstituted water was used as laboratory control while water samples from a highly polluted freshwater source was used as positive control. Developmental parameters were noted and described within 48 and 96 h of exposure. Dilution experiments of the positive control were also done to further assess and compare toxicity potentials of Laguna Lake waters with those originating from a polluted freshwater. After the 96-h exposure, the levels of stress proteins (hsp 70) were determined in embryos from all exposure groups. Results showed 100% mortality in embryos exposed to undiluted positive control (PC) within only 12 h. Increasing dilution levels, however, resulted in lower mortality and lower abnormality rates. No detectable developmental differences were noted among embryos exposed to either the laboratory control or Laguna Lake waters at the end of 96 h, regardless of the source. Very high survival rates and high hatching success rates were observed in embryos exposed to lake waters as well as laboratory control, and the data did not differ significantly among the groups. Likewise, no significant malformations were noted among all developing embryos throughout the exposure period. However, the levels of heat shock proteins in the two sites located closest to Manila, the Philippine capital (Northern West Bay and Central West Bay), showed a pronounced elevation relative to the control, indicating that these stress proteins protect the embryos from the detrimental effects of pollutants in the water. Based on the 96-h early life stage (ELS) test, the water quality of the lake is good for fishery propagation despite the current levels of pollutants in the water. This finding is in accordance with the Class C status (i.e. suitable for fish growth and propagation) as given to the lake by the local environmental agency. On the other hand, data on proteotoxicity showed that the fish are under stress, presumably deriving from pollutants. This calls for a continuous monitoring and improvement of the lake water. The present study indicates that the two biomarker methods are very easy to use, practical, rapid, and sensitive for assessing water quality in a tropical lake and recommends for their incorporation into the future monitoring program of Laguna Lake.     

城乡融合背景下淮海经济区乡村发展潜力——以苏北地区为例

乡村可持续发展与建设是乡村振兴的目标与愿景,也是推进城乡发展一体化、构建可持续城乡融合系统的落脚点,在城市化进程不断加剧背景下,明确乡村发展阶段与状态、测度发展潜力对有效识别乡村未来发展方向和模式、实现乡村可持续发展与建设具有重要意义。以地处淮海经济区核心区的苏北地区为研究对象,以7980个行政村为评价单元研究村域单元的乡村发展状态,通过县域尺度上对城乡发展阶段进行约束,以“差异化+一致性”的思路进行乡村发展潜力的综合测度。研究结果如下：（1）研究区乡村可分为“城镇主导”“城乡联动”和“乡村主导”三类发展阶段,数量占比分别为15.38%、46.15%和38.46%;（2）研究区乡村发展状态指数最大值和平均值分别为6.209和1.714,具有高值区、低值区集聚的特征;（3）研究区乡村发展潜力最大值和平均值分别为2.827和0.923,发展潜力为低、较低、中等、较高和高的评价单元占比分别为4.45%、15.20%、23.22%、35.39%和21.74%;（4）依据乡村发展潜力可将研究区分为“重点挖潜区”“权衡挖潜区”“适度挖潜区”及“重要维护区”四类,建议分别采用“激发隐性活力,缩小区内差距”“以优势要素带动,实现区域权衡发展”“明确发展劣势条件,适度填补潜力空间”及“保持发展模式,实现稳定发展”的发展思路。     

集中荷载下高强箍筋混凝土梁的抗剪性能

通过8根集中荷载下高强箍筋混凝土梁的受剪破坏试验，分析了500MPa箍筋混凝土构件斜截面的剪切承载力及使用阶段的斜裂缝宽度，同时对两组配有蒙皮钢筋的混凝土梁的受剪承载力及斜裂缝宽度进行了对比分析。试验结果表明，此类构件的受力性能与普通钢筋混凝土受剪构件相同，其斜截面受剪承载力仍可按现行《混凝土结构设计规范》有关公式进行计算，并且具有足够的安全储备。同时蒙皮钢筋的配置能够有效地限制裂缝的开展，改善受剪破坏的脆性性能。     

冬小麦品种抗霜力鉴定与霜冻害防御新对策

冬小麦发育进入拔节期和出现霜冻低温是形成其霜冻害的两个要素。霜冻低温的出现主要与气候因素有关。而拔节期的早晚则受初春气温、播种期和选用品种等多种因素的影响。影响品种抗霜力的重要因素是幼穗分化时期。品种抗霜力的鉴定必须在相同的幼穗分化期,建议在药隔期进行。品种的抗霜力还与第1茎节的长度有关,而与抗冻力和叶片可溶性糖含量的相关性不显著。通过研究,提出了下列抗霜对策:在把握地区霜冻温度出现规律的基础上,合理规划抗霜品种与避霜品种的布局;通过常规育种和基因工程手段,改良品种的抗霜力;通过遗传操作磷脂酶D基因,改良冬小麦的抗霜性。     

Estrogenic effects of water from the Yangtze River （Nanjing section） on goldfish （Carassius auratus） after an early life stage exposure

Effects of river water from the Yangtze River (Nanjing section) on fish development, vitellogenin (VTG) induction, gonado-somatic index (GSI) and sex ratio were investigated by exposing goldfish (Carassius auratus) in the early life stage (from fertilization to 28 days post-hatch) to water samples (25%, 50% and 100%) collected from three representative sections. The results showed that there was no significant effect on hatching success for any of the exposure groups, but survival was significantly reduced when compared with the control (P < 0.05). Body lengths, weights of all treated fish did not differ significantly from those of the control. Condition factors (CF) of larval fish exposed to 50% and 100% river water from the Jiangxinzhou section and 100% river water from the Daqiao section were significantly lower than that of the control (P< 0.05). VTG inductions were significant in larval fish exposed to all the dilution series of river water. No significant difference in CF value was observed in any exposure group after 150 days of depuration. VTG was fully eliminated after 75 days of depuration. For both female and male, GSI did not significantly differ between exposure groups and the control after 150 days of convalescence. The highest female:male ratios were observed in response to the treatment with 50% or 100% river water from the Jiangxinzhou section and 100% river water from the Daqiao section (53:47, 56:44 and 54:46, respectively), but no significant difference in sex ratio was observed in any treated group when compared to the control. The results showed that early life stage exposure of river water from the Yangtze River (Nanjing section) had adverse effects on goldfish development and reproductive health, and the effects on CF and VTG were reversible after depuration in clean water.     

茂兰喀斯特森林演替阶段不同小生境的小气候特征

探讨了茂兰喀斯特森林不同演替阶段群落不同小生境的气温、湿度、光照强度和土壤温度的目变化特征,结果表明：各演替群落内大气温度和光照强度随演替逐渐降低,且降幅趋缓;空气相对湿度却随着群落演替而逐渐升高,但变幅减缓;5～20cm土壤温度随演替进展逐渐降低,随着土层深度的增加土温亦呈下降趋势且降温幅度减缓。以乔木林的生态环境和...     

南水北调西线一期工程大渡河流域减水段生态水文浅析

南水北调西线一期工程调水前河流生态水文特征、调水对生态影响的研究对于进一步探讨有利于生态保护的水利工程调控措施具有重要意义。采用IHA方法分析大渡河流域调水区河流调水前的水文资料,提取对基本生态条件维护具有重要意义的月基流量作为特征流量,采用Tennant法评价基流量对生态的有利程度,以历史上曾经发生过的特征流量对生态的意义作为参照,对比分析一期调水工程实施后水文站月平均流量对生态的有利程度,间接推求坝址下游近坝段特征基流量,探究调水后月均流量对生态的有利程度。结果表明：随着沿程流量的恢复,绰斯甲站、足木足站河道水量得到恢复,调水后月平均流量对生态有利程度能达到较好状态;坝址下游河段调水后月平均流量的生态有利程度汛期较差,珠安达和霍那坝址下游6月份甚至为“极差”水平     

长江经济带水资源利用的动态效率及绝对β收敛研究——基于三阶段DEA-Malmquist指数法

利用三阶段DEA-Malmquist指数法,对2009~2014年长江经济带11省市水资源全要素生产率及其分解指数进行了测算和分析。研究结果表明:在剔除了外部环境因素和随机误差因素以后,长江经济带水资源的全要素生产率及其分解效率发生了显著变化,水资源全要素生产率年均增长7.2%,技术进步指数年均增长4.7%,技术效率指数年均增长2.4%,技术进步是推动长江经济带水资源全要素生产率增长的主要源泉。分区域来看,西部地区水资源全要素生产率和技术效率年均增长率最高,东部地区技术进步年均增长率最高。长江经济带水资源全要素生产率存在显著绝对β收敛,表明长江经济带内省际水资源全要素生产率差距正在缩小,最终都朝相同的稳态水平趋近。