基于卸加载响应比的滑坡稳定状态评价与划分

为有效评价与预测滑坡的稳定状态,提出基于卸加载响应比参数的滑坡稳定状态划分的新方法.在阐述卸加载响应比理论内涵的基础上,从损伤力学角度探讨并建立了卸加载响应比与损伤变量的相互关系,并进一步通过分析滑坡稳定安全系数与损伤变量之间的相互关系,建立了卸加载响应比与滑坡稳定安全系数的定量关系.参照相关规范和标准,以卸加载响应比值划分了滑坡稳定状态区间.并以新滩滑坡为例,计算所得卸加载响应比所对应的滑坡稳定状态与实际情况相吻合.说明可以用卸加载响应比参数对滑坡稳定状态进行评价,它与滑坡稳定安全系数一样具有理论和实际应用价值.     

Ecological state equation

The direct equivalence between ecology and thermodynamics has not been attained despite accepted thermodynamic features of the ecosystem. This article explores the homeomorphism between ecology and statistical mechanics by analysis of ruderal vegetation. In conventional thermostatistical algorithm, the pro-kinetic effect of temperature on molecules was replaced by the anti-kinetic effect of species diversity on biological individuals. The existence of an ecological equivalent of the thermodynamic Boltzmann constant was empirically verified. From the relationship of this constant with biocenological variables, we derived a probable ecological equation of state under stationary and quasi-stationary conditions. This equation of state is homeomorphic with regard to the ideal gas state equation, and it is useful to infer the value of some biocenological parameters whose direct measurement is difficult, as biomass, energy and dispersal. According to these results, ecosystem assessment from conventional thermostatistics is plausible and empirically verifiable. This approach offers useful analytical tools for the conservation and restoration of ecosystems.     

Persistent bimodal activity patterns in wild and captive black-tailed godwit <Emphasis Type="Italic">Limosa limosa</Emphasis> under different environmental conditions

There is a large literature dealing with daily foraging routines of wild birds during the non-breeding season. While different laboratory studies have showed that some bird activity patterns are a persistent property of the circadian system, most of field studies preclude the potential role of an endogenous circadian rhythm in controlling bird’s foraging routines. In this study we compared the patterns of diurnal foraging activity and intake rates of migrating black-tailed godwits, Limosa limosa (radio-tagged and non-tagged individuals) at two stopover sites (habitats) with different environmental characteristics, aiming at identifying proximate factors of bird activity routines. To gain insights into the role of food availability in control of such foraging routines, we also estimated foraging activity patterns in captive godwits subjected to constant food availability. Captive and wild black-tailed godwits showed a persistent bimodal activity pattern through daylight period. Food availability had a significant effect on the intake rates, but had a subtler effect on foraging and intake rate rhythms. Temperature and wind speed (combined in a weather index) showed non-significant effects on both rhythms. Although we could not discard a role for natural diurnal changes in light intensity, an important timing cue, our findings support the idea that an endogenous circadian rhythm could be an important proximate factor regulating foraging activity and food items taken per unit time of wild black-tailed godwits during migration.     

Pseudomonas sp.L19抗除草剂AHAS基因的克隆、表达及特性

乙酰羟酸合酶(AHAS)是磺酰脲类、咪唑啉酮类、三唑嘧啶类、磺酰胺类和嘧啶水杨酸类等乙酰羟酸合酶抑制剂类除草剂的作用靶标,获得能抗此类除草剂的AHAS突变基因资源具有非常重要的理论和应用价值.从长期使用甲磺隆的农田土壤中分离到1株对乙酰羟酸合酶抑制剂类除草剂有广谱抗性的菌株L19,根据表型特征、生理生化特性和16S rDNA序列系统发育分析,将其鉴定为假单孢菌属(Pseudomonas sp.).利用PCR技术从Pseudomonas sp.L19的总DNA中克隆AHAS基因,氨基酸序列比对结果表明,L19与对除草剂敏感菌株P.putida KT2440的AHAS调节亚基氨基酸序列完全相同,而催化亚基有4个氨基酸位点不同:[Val 29→Ala(L19→KT2440),Pro93→Ser,Val 345→Ala,Pro 484→Arg].分别将菌株L19与KT2440的AHAS催化亚基克隆到pET29a(+)的多克隆位点,构建了表达载体pET-L19AHASc和pET-KT2440AHASc,通过镍柱亲和层析纯化得到带有组氨酸标签的乙酰羟酸合酶.抗性试验结果表明菌株L19的乙酰羟酸合酶对四大类乙酰羟酸合酶抑制剂类除草剂的抗性均要强于KT2440的乙酰羟酸合酶,对甲磺隆、咪唑乙烟酸、唑嘧磺草胺和嘧草醚的抗性倍数分别达到53.6、9.3、8.2和9.5倍.菌株L19的乙酰羟酸合酶比活力、对ThDP和Mg2+的Kc值相应地比KT2440乙酰羟酸合酶的要低;而对底物丙酮酸钠的米氏常数Km值要比KT2440乙酰羟酸合酶的要高近1倍.     

日本城市碳排放清单计算方法——以横滨市为例

日本是关注全球气候变化并作出行动最早的国家之一,根据其法律大中城市以上的行政区必须编制温室气体减排规划,包括排放清单、趋势预测、减排目标、措施及效果分析、方案实施与监督等。日本环境省为了帮助地方政府编制该规划,提供了城市层面的温室气体排放清单的编制方法指导。本文以横滨市为例,比较完整地介绍日本城市CO2排放清单编制基本方法,为我国城市碳排放清单编制提供参考。     

微咸水膜下滴灌对白僵土盐碱地水盐特性及油葵生长的影响

为了解滴灌条件下不同微咸水矿化度及覆膜与否对盐碱地土壤水盐特性及油葵生长的影响,在宁夏平罗西大滩盐碱地进行不同灌水矿化度(0.2、1、2、3 g/L)膜下滴灌田间试验.结果表明,地膜覆盖比不覆盖处理土壤含水量高约2%,盐分表聚减缓,油葵株高、产量及其构成均高于不覆膜处理,产量最高增幅达82.5%;不同矿化度微咸水之间比较发现,利用矿化度为1 g/L的微咸水进行灌溉时,下层土壤含水量较高,微咸水滴灌不但没有为上层土壤带去过多盐分,反而由于土壤有一定的渗透性能,灌水将土壤上层盐分逐渐淋洗至下层.膜下滴灌微咸水矿化度为1 g/L时,油葵产量最大.因此在适宜条件、合理措施下,微咸水覆膜滴灌技术可以促进作物生长,确保作物产量,在淡水缺乏而微咸水较为丰富的盐碱地地区应积极推广利用.     

具有微囊藻毒素清除能力的乳酸菌的分离筛选及其影响因素

微囊藻毒素是由蓝藻产生的环状多肽物质,可引发人类肝中毒等健康问题,因此微囊藻毒素的清除对食品安全和环境保护有着深远的意义.本研究从泡菜、腊肠等传统发酵食品中分离筛选获得33株乳酸菌,通过对其微囊藻毒素清除能力的测定,获得一株具有高效微囊藻毒素清除能力的乳酸菌菌株干酪乳杆菌BBE10-212.实验发现菌体浓度、藻毒素浓度、菌体活性等因素对实验菌株清除藻毒素的效能具有显著影响,此外,外源添加5%的葡萄糖可使藻毒素清除率提高至52%,远高于未添加时的19%.而外源添加替代藻毒素的微生物发酵氮源以及作为部分代谢关键酶辅酶的金属离子则会抑制菌体对藻毒素的清除效率.研究结果为深入分析实验菌株清除微囊藻毒素的作用机制,实现微囊藻毒素的生物干预策略,并基于对菌株的代谢调控促进微囊藻毒素的高效降解提供了数据和资料.     

Effects of recreational disturbance on tidal wetlands: supporting the importance of undisturbed roosting sites for waterbird conservation

In coastal wetlands, the increasing level of disturbance from recreational activities could threaten waterbird populations, which overall are showing decreasing trends. Despite the crucial contribution of waterbirds to biodiversity, empirical studies measuring the effects of disturbance on them remain scarce, especially in terms of the impact upon their roosting sites. We developed an experimental treatment to measure the effects of a pedestrian walking on a site used by overwintering waterbirds in a wetland of international importance. We registered 156 events (88 at high tide) of flushing birds, totaling 4,018 individuals. Each treatment drove the flushing of 1?C5?% of the wintering populations of nearly all species present during high tide. In addition, 1.5?% of the Eurasian curlew wintering population was driven to change site. All the effects were found to be reduced during other tidal periods. Therefore, allowing recreational use in a previously undisturbed area can systematically increase daily energy expenditure of significant percentages of different waterbird populations during high tide, and even cause birds to avoid a site completely. These effects will probably be even worse given that our results were derived only from a disturbance source of low magnitude and frequency. We recommend that, prior to developing recreational areas close to the shoreline, coastal wetland managers should study the habitat use of waterbirds during high tide in relation to total waterbird populations using the wetland.     

Geologic processes influence the effects of mining on aquatic ecosystems

Geologic processes strongly influence water and sediment quality in aquatic ecosystems but rarely are geologic principles incorporated into routine biomonitoring studies. We test if elevated concentrations of metals in water and sediment are restricted to streams downstream of mines or areas that may discharge mine wastes. We surveyed 198 catchments classified as "historically mined" or "unmined," and based on mineral-deposit criteria, to determine whether water and sediment quality were influenced by naturally occurring mineralized rock, by historical mining, or by a combination of both. By accounting for different geologic sources of metals to the environment, we were able to distinguish aquatic ecosystems limited by metals derived from natural processes from those due to mining. Elevated concentrations of metals in water and sediment were not restricted to mined catchments; depauperate aquatic communities were found in unmined catchments. The type and intensity of hydrothermal alteration and the mineral deposit type were important determinants of water and sediment quality as well as the aquatic community in both mined and unmined catchments. This study distinguished the effects of different rock types and geologic sources of metals on ecosystems by incorporating basic geologic processes into reference and baseline site selection, resulting in a refined assessment. Our results indicate that biomonitoring studies should account for natural sources of metals in some geologic environments as contributors to the effect of mines on aquatic ecosystems, recognizing that in mining-impacted drainages there may have been high pre-mining background metal concentrations.     

纳米Fe3O4对小鼠肺细胞的氧化损伤

纳米Fe3O4作为一种功能材料,在生物医药、生物靶向材料、微波吸收材料和高梯度磁分离器等方面应用前景广阔,其潜在的生物毒性也备受关注。为研究纳米Fe3O4对生物体可能造成的氧化损伤,以昆明小鼠为受试体,设置5、10、20和40mg·kg-14个染毒组,腹腔注射染毒7d后,测定小鼠肺组织中活性氧(reactive oxygen species,ROS)、还原型谷胱甘肽(glutathione,GSH)和丙二醛(malondialdehyde,MDA)的含量。结果显示,随着纳米Fe3O4染毒剂量的升高,肺组织ROS和MDA含量逐渐上升,GSH含量逐渐降低,各指标均呈一定的剂量-效应关系。剂量≥10mg·kg-1,肺组织ROS含量与对照组相比有显著差异(p<0.05);剂量≥20mg·kg-1,肺组织MDA含量与对照组相比有显著差异(p<0.05);剂量≥40mg·kg-1,肺组织GSH含量与对照组相比有显著差异(p<0.05)。研究表明,较高剂量(≥20mg·kg-1)的纳米Fe3O4颗粒材料会引起小鼠肺细胞的氧化损伤。