Testing the applicability of a Marine Biotic Index (AMBI) to assessing the ecological quality of soft-bottom benthic communities, in the South America Atlantic region

Recently, several monitoring programmes have been undertaken to evaluate the impact of different anthropogenic activities, upon a range of coastal ecosystems located in the South-western Atlantic. In the present contribution, the applicability of the AZTI's Marine Biotic Index (AMBI) is tested, to establish the benthic health of the ecosystem using these data sets. As the AMBI was created previously for use in European estuarine and coastal environments, its general applicability to new geographical locations is discussed. In general, the results are in agreement with those obtained using traditional univariate and multivariate methods. Some inconsistent results are observed, when low abundances and/or number of taxa are recorded in the samples. Moreover, when the macrofauna samples are dominated by large nematodes, the classification of the benthic ecosystem health using AMBI is not consistent with previous results achieved applying other statistical techniques. Thus, parallel to the application of this index to a wider extend, the complementary use of different indices and/or methods is recommended to assess confidently the environmental quality of a coastal area.     

Developing a Radiative Shock Experiment Relevant to Astrophysics

We assume that internal shocks of gamma-ray bursts (GRBs) consist of multiple sub-jets with a collimation half-angle of about several times gamma-1i, where gammai is the Lorentz factor of each sub-jet. If by chance a sub-jet is first emitted off-axis from the line of sight, the observed peak energy can be in the X-ray region. Next, if by chance a subsequent sub-jet is emitted along the line of sight, then the peak energy will be in the gamma-ray region and the gamma ray may arrive after the X-ray precursor from the former sub-jet depending on parameters. This model predicts a new class of GRBs with extremely weak and short gamma-ray emission but X-ray precursors and/or postcursors as well as an afterglow.     

应用小台阵资料对统计最佳事件检测的研究

介绍了检测和估计地震信号的Ｃａｐｏｎ最大似然技术。通过采用地震台阵噪声的多维自回归近似,提出了一项用Ｃａｐｏn的多通道滤波技术作为在线处理,结果表明这种适用于通 用噪声矩阵功率谱的自回归方法能很好地抑制互相关台阵噪声。作为一个例,子,用这项技术对ＡＲＣＥＳＳ台阵到的塞米巴拉金斯克小当量地下核爆炸记录进行检测。     

用台阵资料研究地震散射

应用高频地震台阵资料我们能研究频带１～１０Ｈz同伯地震波场空间和时间的特征。作者 对ＮＯＲＥＳＳ、ＦＩＮＥＳＡ和ＡＲＣＥＳＳ的地震波散射进行了研究。研究应用了两种主要方法,即尾波的频率－波数分析和地震相位的相干性分析。对区域地震记录,Ｌg尾波的频率－波数分析表明Ｌg到Ｌg的散射是主要的,且散射开始集中在正向,在尾波的后面变成了均匀的反射散射。Ｐ尾波的情况更加复杂,尽管研究的所有情况表明能量是集中的方位     

An obsolete dichotomy? Rethinking the rural–urban interface in terms of food security and production in the global south

The global food system is coming under increasing strain in the face of urban population growth. The recent spike in global food prices (2007–08) provoked consumer protests, and raised questions about food sovereignty and how and where food will be produced. Concurrently, for the first time in history the majority of the global population is urban, with the bulk of urban growth occurring in smaller-tiered cities and urban peripheries, or ‘peri-urban’ areas of the developing world. This paper discusses the new emerging spaces that incorporate a mosaic of urban and rural worlds, and reviews the implications of these spaces for livelihoods and food security. We propose a modified livelihoods framework to evaluate the contexts in which food production persists within broader processes of landscape and livelihood transformation in peri-urban locations. Where and how food production persists are central questions for the future of food security in an urbanising world. Our proposed framework provides directions for future research and highlights the role of policy and planning in reconciling food production with urban growth.     

Terrestrial pollutant runoff to the Great Barrier Reef: An update of issues, priorities and management responses

The Great Barrier Reef (GBR) is a World Heritage Area and contains extensive areas of coral reef, seagrass meadows and fisheries resources. From adjacent catchments, numerous rivers discharge pollutants from agricultural, urban, mining and industrial activity. Pollutant sources have been identified and include suspended sediment from erosion in cattle grazing areas; nitrate from fertiliser application on crop lands; and herbicides from various land uses. The fate and effects of these pollutants in the receiving marine environment are relatively well understood. The Australian and Queensland Governments responded to the concerns of pollution of the GBR from catchment runoff with a plan to address this issue in 2003 (Reef Plan; updated 2009), incentive-based voluntary management initiatives in 2007 (Reef Rescue) and a State regulatory approach in 2009, the Reef Protection Package. This paper reviews new research relevant to the catchment to GBR continuum and evaluates the appropriateness of current management responses.     

利用背景噪声互相关研究汶川地震震源区地震波速度变化

利用2007年3月至2009年3月四川数字地震台网的宽频带连续波形资料,通过计算地震背景噪声互相关提取台站对间的经验格林函数,在0.1～0.5 Hz频带下测量每天经验格林函数与参考经验格林函数的走时偏移,进而得到各台站对在该时段内的相对地震波速度变化.结果表明,2008年5月12日汶川M_s8.0级地震造成了震源区地震波速度的急剧降低,最大降幅达0.4%;大致以安县为界,余震带西南部地区在汶川主震后波速降即达到最大值,而东北部地区的最大波速降一般出现在主震后的1~4个月,相对地震波速度变化的这种分段特性与地震序列的时空分布特征有较好的对应关系;在震源区外围的四川盆地也观测到了震后波速降低,而川西高原内部则没有出现显著的波速变化.进一步的分析和计算结果表明主震的静态应力变化和强地面运动引起的地表破坏都不能很好地解释震后波速的急剧降低,地震导致的断层区内部结构破坏和周边介质应力状态改变可能是波速变化的主要原因.     

(137)Cs baseline levels in the Mediterranean and Black Sea: a cross-basin survey of the CIESM Mediterranean Mussel Watch programme

The common mussel Mytilus galloprovincialis was selected as unique biomonitor species to implement a regional monitoring programme, the CIESM Mediterranean Mussel Watch (MMW), in the Mediterranean and Black Seas. As of today, and upon standardization of the methodological approach, the MMW Network has been able to quantify (137)Cs levels in mussels from 60 coastal stations and to produce the first distribution map of this artificial radionuclide at the scale of the entire Mediterranean and Black Seas. While measured (137)Cs levels were found to be very low (usually < 1 Bq kg(-1) wet wt) (137)Cs activity concentrations in the Black Sea and North Aegean Sea were up to two orders of magnitude higher than those in the western Mediterranean Basin. Such effects, far from representing a threat to human populations or the environment, reflect a persistent signature of the Chernobyl fallout in this area.