Biomarkers in croakers Micropogonias furnieri (Teleostei: Sciaenidae) from polluted and non-polluted areas from the Patos Lagoon estuary (Southern Brazil): evidences of genotoxic and immunological effects

Biomarkers of exposure and effect of pollutants were analyzed in croakers Micropogonias furnieri (Teleostei: Sciaenidae) captured in winter and summer in a polluted and in a non-polluted site at the Patos Lagoon estuary (Southern Brazil). Catalase and glutathione S-transferase activities (exposure biomarkers) and lipid peroxidation (effect biomarker) were analyzed in liver samples. Other two effect biomarkers were also studied: blood cells DNA damage (through comet assay and micronucleus test) and respiratory burst measurements. In a broad view, results point to an important seasonal variation of the biochemical biomarkers analyzed. However, data obtained clearly indicate that croakers collected in winter at the polluted site were subjected to a level of clastogenic agents sufficient to generate irreversible genetic damages (mutations) and impair the fish immune system.     

P-T conditions of earliest Late Cretaceous metamorphism in the Western Sonobari Complex,northwestern Mexico: tectonic implications

The Western Sonobari Complex in northwestern Mexico consists of metamorphosed rocks mostly derived from Palaeozoic (?) sedimentary and Mesozoic igneous protoliths. Rocks of this complex display amphibolite facies orogenic metamorphism, pervasive foliation, migmatization, and four folding phases. These features are ascribed to a contractional tectonic event with NNW–SSE shortening direction, which caused thrusting, thickening of the crust, and sinking of the lithological units. U–Pb geochronology of migmatitic leucosome bands indicates that peak metamorphic conditions were reached between ~93 and 89 Ma. Post-tectonic Late Cretaceous peraluminous aplite-pegmatite dikes transect the metamorphic foliation. Traditional thermobarometry in the metamorphic rocks yields average pressures and temperatures of 9.0–7.1 kbar and 745–663°C, typical of intermediate P/T Barrovian metamorphism. On the basis of its age and contractional character, the thickening event originating the metamorphism may be related to collision of the Alisitos island arc against crustal blocks of Mexico. Thermobarometric data of post-tectonic intrusives including Late Cretaceous granodiorite and Eocene gabbro indicate emplacement within an overthickened crust, while P-T conditions of post-tectonic dikes point towards an almost isothermal decompression path along the amphibolite facies field. Rock units of similar age and metamorphic character are discontinuously exposed from the Islas Marias offshore the Nayarit coast to the Peninsular Ranges batholith of Baja California, and even extend north into the Sierra Nevada batholith and the Sevier hinterland. This extensive belt of Barrovian metamorphic rocks thus provides a record of middle Cretaceous shortening and crustal thickening related to arc-continent collision followed by subduction resuming.     

Inspiring the next generation of scientists with their observations of quasars,black holes,Jupiter, and SETI with the Goldstone Apple Valley Radio Telescope,GAVRT

This paper describes a radio astronomy programfor schools, the Goldstone-AppleValley Radio Telescope,GAVRT. The GAVRT program is designed to bring the inspiration and enthusiasm to a younger generation of teachers and children who learn about science by doing real science, just as Iosif Shklovsky brought to an older generation.     

珠峰地区积雪变化与气候变化的关系

根据三次Landsat遥感数据,应用GIS空间分析方法,分析了1975-2000年珠峰地区定日县常年积雪变化特征,并探讨其与气候变化之间的关系。结果表明,1975-2000年间定日县内常年积雪总计减少了7.49％,减少面积为105.35 km2,主要发生在珠峰及其周围高大山体常年积雪覆盖的边缘地区,其中,海拔5 000～6 000 m之间减少最多,占减少总面积的70％左右。气温和降水量变化是导致常年积雪变化的主要因素,特别是在全球变暖的大背景下,珠峰地区的气温上升趋势是其主要驱动因子。气温升高导致珠峰及周围高大山脉边缘的冰川和常年积雪不断消融,加上1980年代的降水量相对较少,使得1975-1992年常年积雪面积不断减少;但1990年代后期降水量增加显著,研究区东南部海拔相对较低的区域有较多的积雪累积,1993-2000年常年积雪面积略有增加。     

Variations of the Surface Wettability Index over the Tibetan Plateau During 1971-2005

Based on 1971-2005 monthly mean maximum/minimum temperature,wind speed,relative humidity,sunshine duration,and precipitation data at 25 stations over the Tibetan Plateau,a study of the largest potential evapotranspiration(LPE)is performed by using the Penman-Monteith model.The surface wettability index(SWI)is calculated and examined,together with its space distribution,interannual and seasonal variations,as well as associated causes.The results suggest that the annual area rainfall exhibits a pronounced increasing trend at 15.0 mm per decade; the annual LPE shows a different-degree decrease at-4.6-71.6 mm/10 yr.In the southwestern Ngari prefecture and Nyalam county,the annual SWI displays insignificant decline trends compared to increasing trends in other areas of Tibet(0.02-0.09 per decade).For Tibet,on average,the SWI experiences a noticeable rise at 0.04/10 yr,particularly in 1981-2005.On a seasonal basis,the SWI shows increasing trends,especially in summer.In the 1970s-1980s,the interannual variation is characterized mainly by lower temperature and lower humidity.From the 1990s,air temperature keeps on rising,leading to an appreciable increase in SWI,displayed as a type of warm and humid climate.The salient increases(decrease)of precipitation and relative humidity(mean temperature daily range)are the principal causes of the greatly enhanced SWI in the region.The pronounced decrease in mean wind and sunshine duration also plays an active role.     

盐生植物萌发期对盐胁迫的适应研究进展

目前我国盐渍土地面积较大,尤其是青藏高原的盐渍地,常伴有干旱、半干旱的生境,导致植物不易生长,生态环境相对恶劣,这种生态现状亟待解决。盐生植物具有一定的耐盐性和耐旱性,是改善盐渍地的首选植物,种子的活力决定了种子萌发的情况,多数学者为改善严峻的生态环境开始了盐生植物引种的研究。测定种子活力有直接方法和间接方法,大多数学者采用的是直接方法,即在实验室模拟一定条件直接测定萌发率。简述了盐生植物的概况、制造胁迫的主要方法以及检测种子活力的指标,综述了近年来不同学者对盐爪爪、白刺等具有代表性的22种盐生植物在种子萌发期的耐盐性以及抗旱性的相关研究,为改善盐渍地的生态环境、提升盐渍地的生产量提供了理论基础。     

Aggradation and carbonate accumulation of Holocene Norwegian cold‐water coral reefs

Cold‐water coral ecosystems present common carbonate factories along the Atlantic continental margins, where they can form large reef structures. There is increasing knowledge on their ecology, molecular genetics, environmental controls and threats available. However, information on their carbo‐nate production and accumulation is still very limited, even though this information is essential for their evaluation as carbonate sinks. The aim of this study is to provide high‐resolution reef aggradation and carbonate accumulation rates for Norwegian cold‐water coral reefs from various settings (sunds, inner shelf and shelf margin). Furthermore, it introduces a new approach for the evaluation of the cold‐water coral preservation within cold‐water coral deposits by computed tomography analysis. This approach allows the differentiation of various kinds of cold‐water coral deposits by their macrofossil clast size and orientation signature. The obtained results suggest that preservation of cold‐water coral frameworks in living position is favoured by high reef aggradation rates, while preservation of coral rubble prevails by moderate aggradation rates. A high degree of macrofossil fragmentation indicates condensed intervals or unconformities. The observed aggradation rates with up to 1500 cm kyr^?1 exhibit the highest rates from cold‐water coral reefs so far. Reef aggradation within the studied cores was restricted to the Early and Late Holocene. Available datings of Norwegian cold‐water corals support this age pattern for other fjords while, on the shelf, cold‐water coral ages are reported additionally from the early Middle Holocene. The obtained mean carbonate accumulation rates of up to 103 g cm^?2 kyr^?1 exceed previous estimates of cold‐water coral reefs by a factor of two to three and by almost one order of magnitude to adjacent sedimentary environments (shelf, slope and deep sea). Only fjord basins locally exhibit carbonate accumulation rates in the range of the cold‐water coral reefs. Furthermore, cold‐water coral reef carbonate accumulation rates are in the range of tropical reef carbonate accumulation rates. These results clearly suggest the importance of cold‐water coral reefs as local, maybe regional to global, carbonate sinks.     

基于MODIS的藏北高原植被分类研究

本文以那曲地区和拉萨市区(文中称藏北高原)作为研究对象,对该区域的植被进行分类。通过地面调查数据、遥感数据、中国植被图集扫描图中经几何校正的西藏藏北高原作为实际参考数据,利用R2V软件和Arc info软件的结合,得出西藏藏北高原植被的数字化图。同时通过中国植被图集中西藏藏北高原的数据和MOD IS卫星6、2、1通道合成数据的特点,利用最大似然估计监督类方法对2004年9月13和27日的EOS/MOD IS卫星遥感图像的西藏藏北高原部分植被进行分类。得出西藏藏北高原7个典型植被类型及其面积,可以反映出该区域植被的特征。这对可持续发展该区域的草地资源提供了决策依据。     

大别造山带宿松杂岩中石榴斜长角闪岩变质演化过程、原岩时限及其构造涵义

大别造山带是由扬子板块向华北板块俯冲碰撞而形成的, 出露了世界上规模最大的、种类最齐全的各类超高压岩石, 全面深刻地记录了大陆深俯冲过程。然而, 对于该造山带"浅层"(地壳层次)俯冲折返过程的研究则较少涉及, 这制约了对大别造山带形成全过程的整体理解。为此, 本次研究以大别造山带最南缘经历绿帘-角闪岩变质的宿松杂岩为研究靶区, 针对该杂岩别河地区的石榴斜长角闪岩展开了精细的岩相学、矿物化学、温压评价和年代学研究。研究表明, 该岩石记录了三个变质阶段, 其中第二阶段可进一步分为a和b两个亚阶段, 具体的变质温压条件分别为: ①阶段Ⅰ: T=562±12℃、P=1.03±0.05GPa; ②阶段Ⅱ-a: T=663±8℃、P=1.09±0.04GPa; ③阶段Ⅱ-b: T=508~584℃、P-设定=0.5~0.7GPa; ④阶段Ⅲ: T=396~472℃、P-设定=0.1~0.3GPa。其中, ①→②表现为近等压增温型式, 反映了一个俯冲迟滞过程, 暗示了"浅层"俯冲止于莫霍面附近, 并受下伏岩石地幔热源供给导致其持续增温, 而②→③→④则显示降温降压样式, 表现为缓慢抬升的过程。显然, 大别造山带"浅"地壳层次的俯冲属于"暖"俯冲类型, 并表现为一个缓慢变质演化过程, 明显不同于大别造山带"冷"俯冲类型的大陆深俯冲的快速演化过程。锆石U-Pb年代学研究显示, 石榴斜长角闪岩的锆石均为具振荡环带结构, 测定的37个谐和年龄范围数据范围为1470±80Ma~1258±101Ma, Th/U比值均大于0.4, 加权平均年龄为1381±25Ma, 该年龄应为其原岩结晶年龄, 代表了哥伦比亚超大陆最终裂解时限。此外, 侵入于石榴斜长角闪岩中的富石英花岗岩的加权平均年龄为129±5Ma, 反映了中国东部中生代伸展事件。结合前人的年龄资料, 可以推测1.38~1.30Ga为哥伦比亚超大陆向罗迪尼亚超大陆转换的时间节点。同时, 可以明确宿松杂岩则是由不同时代、不同岩石类型构成的单元, 是探究扬子板块自新太古代至中生代漫长复杂的演化过程最佳的场所变质单元。     

NPP-VIIRS卫星在西藏植被监测中的应用研究

基于GIS空间分析和数学统计方法,利用TERRA、AQUA和NPP-VIIRS卫星数据反演了西藏日土县植被归一化指数（Normalized Difference Vegetation Index,NDVI）,并对不同卫星传感器反演结果的一致性进行了检验评估。结果表明：NPP-VIIRS卫星反演的NDVI值略大于TERRA和AQUA的反演值,其估算结果与MODIS卫星估算值存在较好的相关性。NPP-VIIRS卫星可以用于西藏高原植被长势监测工作,为西藏生态文明高地建设提供更加丰富的遥感数据支撑。