Temporal changes of a macrobenthic assemblage in harsh lagoon sediments

An opportunistic macrobenthic assemblage was studied from 2001 to 2003 in a central area of the Cabras lagoon (western Sardinia, Italy), known to be affected by environmental disturbances (i.e. organic over-enrichment of sediments, and episodic events of hypoxia/anoxia and sulphide development). We identified recurrent seasonal changes in this macrobenthic assemblage, with a general impoverishment in summer and a recovery in winter/spring. The nereids Neanthes succinea and Hediste diversicolor were found to replace the spionid Polydora ciliata as the most dominant species in the summer for 3 consecutive years. Occasional, unsynchronized appearances of small-sized deposit feeders, such as Tubificidae, Capitella cf. capitata, chironomid larvae and Hydrobia spp., were observed in winter/spring. We suggest that these changes are driven by the interplay of environmental conditions (worse in summer) with numerous biotic factors. This includes different tolerance levels of taxa to low oxygen concentrations and sulphides, variability in larval supply and post-larval transport, as well as competition for space and food between and within different functional groups, and facilitation through animal bioturbation and sediment reoxidation. A conceptual model is proposed to demonstrate how environmental conditions and biotic interactions may control the benthic assemblage in such a harsh lagoon environment.     

富油微藻富碳培养下油脂积累及固碳研究

微藻固碳是一种新型节能减排技术,具有长期可持续发展的潜力。本文对两株富油微藻（球等鞭金藻和微拟球藻）进行了富碳培养下生长特性及中性脂积累特性的研究。两株富油微藻的最佳培养条件为10%CO₂浓度和f培养基。本研究对两株富油微藻的最大生物量产率、总脂含量、最大油脂产率、微藻的C含量和CO₂固定率进行了测定。球等鞭金藻的各参数指标分别为：142.42±4.58g/（m²·d）,39.95%±0.77%,84.47±1.56g/（m²·d）,45.98%±1.75%和33.74±1.65g/（m²·d）。微拟球藻的各参数指标分别为：149.92±1.80g/（m²·d）,37.91%±0.58%,89.90±1.98g/（m²·d）,46.88%±2.01%和34.08±1.32g/（m²·d）。实验结果显示,两株海洋微藻均属于高固碳优良藻株,适合应用于微藻烟气减排技术开发,具备用于海洋生物质能耦合CO₂减排开发的潜力。     

语义轨迹建模与挖掘研究进展

语义轨迹是时空轨迹和语义信息融合的产物。除了含有时空信息以外,语义轨迹包括移动对象自身的运动状态（如速度、方向）、环境（如气温、空间拓扑关系）和社交关系（如好友关系、社交活动）等多方面信息。挖掘语义轨迹可以深入地发现个体或群体移动行为的意图、习惯、情感等高阶语义内容,从而深层次发现个体或群体移动行为的模式、关系和规律等。因而,相较于时空轨迹,语义轨迹在语义性、解释性、可行性等方面更符合决策分析应用的实践需求,具有更重要的研究意义和应用价值。本文对语义轨迹挖掘的关键技术进行了综述。首先,介绍语义轨迹的基本概念,并且根据语义元素类型的不同总结了4种常见的定义形式。其次,归纳了语义轨迹建模的基本阶段,包括预处理、轨迹分段和语义富化。由于语义轨迹无法像时空轨迹那样从位置感知设备中采集获得,因此语义轨迹是通过建模技术得到的,主要通过将语义信息和时空轨迹相融合生成相应的语义轨迹。然后,介绍语义轨迹挖掘的主要任务,包括语义轨迹模式挖掘、语义轨迹聚类、语义轨迹分类、语义轨迹异常检测等。针对每一项挖掘任务,介绍了有关的基本原理和相关算法,总结了主要的关键技术和挑战。最后,探讨了语义轨迹挖掘现存的研究难点和未来研究方向。从模型定义、语义标注技术、多源数据建模等方面,讨论了语义轨迹建模的重要研究问题;从语义轨迹数据管理、分类和预测、流式数据挖掘、隐私保护、多粒度挖掘、评价方法等方面,探讨了语义轨迹挖掘的未来研究问题。     

Chemical composition of PM2.5 at an urban site of Chengdu in southwestern China

PM2.5 aerosols were sampled in urban Chengdu from April 2009 to January 2010, and their chemical compositions were characterized in detail for elements, water soluble inorganic ions, and carbonaceous matter. The annual average of PM2.5 was 165g m－3, which is generally higher than measurements in other Chinese cities, suggesting serious particulate pollution issues in the city. Water soluble ions contributed 43.5% to the annual total PM2.5 mass, carbonaceous aerosols including elemental carbon and organic carbon contributed 32.0%, and trace elements contributed 13.8%. Distinct daily and seasonal variations were observed in the mass concentrations of PM2.5 and its components, reflecting the seasonal variations of different anthropogenic and natural sources. Weakly acidic to neutral particles were found for PM2.5. Major sources of PM2.5 identified from source apportionment analysis included coal combustion, traffic exhaust, biomass burning, soil dust, and construction dust emissions. The low nitrate: sulfate ratio suggested that stationary emissions were more important than vehicle emissions. The reconstructed masses of ammonium sulfate, ammonium nitrate, particulate carbonaceous matter, and fine soil accounted for 79% of the total measured PM2.5 mass; they also accounted for 92% of the total measured particle scattering.     

特提斯构造域东段叠合盆地演化和油气成藏规律特征初论

通过分析特提斯构造域东段区域地质和含油气盆地勘探开发基础数据,从板块构造演化入手,系统编制特提斯构造域东段沉积构造演化剖面图和生储盖组合剖面图,研究盆地演化阶段、叠合特征、油气成藏条件及油气藏类型,揭示中亚和中国西部前陆盆地演化和油气富集规律异同.研究表明:古亚洲洋、古特提斯洋和新特提斯洋控制了特提斯构造域东段的区域构...     

西藏甲玛铜多金属矿富银矿体地质特征、银赋存状态及富集机理研究

位于西藏墨竹工卡县的甲玛铜多金属矿床是冈底斯中东段近年来新发现的超大型矿床,已探明伴生银资源量大于6000t.根据产出特征可将甲玛矿区的银矿体分为矽卡型与大理岩型两种.通过矿相学、电子显微探针研究发现银均以不可见银和可见银两种形式存在.不可见银以晶格银的形式赋存于铜矿物中;其次以次显微包体银的形式赋存于方铅矿中.可见银...     

青海江里沟钨多金属矿成矿控制因素及矿化富集规律

青海江里沟钨多金属矿床目前是青海境内规模最大的钨矿床,其规模达中-大型,大地构造位置属秦祁昆复合造山系秦岭造山带西段。本文从江里沟钨多金属矿床的成矿地质背景、矿区地质特征、矿体特征等方面入手,总结矿床控矿因素及矿化富集规律。矿体受岗察复式花岗岩体与围岩接触带控制,矿化围绕岩体具有明显的分带性,自岩体向外形成了斑岩型钼矿化-云英岩型钨矿-矽卡岩型钨铜钼矿-角岩型钨矿-脉状铅锌矿的矿化系列,以矽卡岩型为主要类型。其矿床成因为与晚三叠世江里沟复式花岗岩体晚阶段花岗斑岩和细粒花岗岩的侵入及岩浆后期热液有关的多位一体矿床,为下一步的找矿提供依据。     

成都市大气颗粒物污染特征及其来源分析

通过在夏、冬两季分别进行的三种粒径颗粒物同步连续采样监测试验,确定了成都市大气颗粒物细颗粒物污染严重且有明显二次污染的污染特征。用多重回归分析、富集因子分析及化学成分的因子分析等方法对颗粒物的化学组成及其来源进行了定性分析,结果表明成都市可吸入颗粒物主要来源于化石类燃料及油品燃烧、生物质或餐饮烹饪行业排放、建筑及冶金行业的排放等。     

Enrichment of heavy metals in coal gangue by puff balls and mechanism research

Coal gangue with/without wild puff balls growing on or covering up were analyzed by means of inductively coupled plasma atomic emission spectrometry （ICP-AES） and atomic fluorescence spectrometry （AFS） to detect the contents of heavy metal elements in the plants. Seven heavy metals were chosen to do the experiments, which showed that the puffballs have strong enrichment capacity for heavy metals （As, Pb, Mn and Ni）. The highest enrichment level was Mn, 220.3 mg/kg （dry weight） for puffball fruiting bodies, and the highest As, Cr and Pb enrichment levels for puffball mycelium were 111,265.3 and 86 mg/kg, respectively. Cd, Mn and Ni could transfer from puffball mycelium to its fruiting bodies, while As, Cr, Pb and Co mainly accumulated in the mycelium. The contents of five organic acids （tartaric acid, glycolic acid, lactic acid, citric acid and malic acid） in puffballs were determined with high performance liquid chromatography. With water, ethanol and ethyl acetate as solvents, the puffball extracts performed dissolution reactions with coal gangue, in which the water extract （containing a large amount of organic acids） was most effective in releasing heavy metals, especially As, Pb, Cr, Mn, Co and Ni from coal gangue. As a pioneer species, puff balls absorbed the hazardous trace elements in coal gangue matrix to reduce its eco-toxicity, on the other hand, it raised the pH value of coal gangue, improving the vegetation growing conditions for coal gangue matrix to a certain extent and laying the foundation for ecological restoration of coal gangue dumps.     

山西沁水煤田煤中铀的含量分布特征及开发前景研究

煤型铀矿的合理开采和综合利用,对于缓解我国天然铀供需矛盾具有重要意义。山西组煤层中的铀含量(3.00×10^-6)小于太原组煤层的值(4.96×10^-6)。同时,山西组1号煤、4号煤中铀含量大于3(2)煤中铀含量;太原组15号煤中铀含量最小,其它煤层煤中铀含量有从上到下增加的趋势。对于沁水煤田煤中铀的富集成矿,应重点关注煤田东南部长子-高平区域,铀在该区域的3(2)号煤层和15(9+10)号煤层中均有富集,总预测量达67141t,成矿前景良好,另外,煤田东北部寿阳区域煤中铀资源也较为丰富。