ALBERT

Description: The Agulhas system all the interface between the Indian and Atlantic Ocean is an important region in the global oceanic circulation with a recognized key role in global climate and climate change. The simulation of the Agulhas system was performed by a high-resolution regional model nested in a global coarse-resolution ocean model. It is shown that this model simulates all characteristics of the Agulhas regime in a highly realistic manner. Due to the two-way coupling of both models the importance of the Agulhas leakage on the large-scale thermohaline circulation was demonstrated.

Description: The Chile subduction zone, spanning more than 3500 km, provides a unique setting for studying, along a single plate boundary, the factors that govern tectonic processes at convergent margins. At large scale, the Chile trench is segmented by the subduction of the Chile Rise, an active spreading center, and by the Juan Fernández hot spot ridge. In addition, the extreme climatic change from the Atacama Desert in the north to the glacially influenced southern latitudes produces a dramatic variability in the volume of sediment supplied to the trench. The distribution of sediment along the trench is further influenced by the high relief gradients of the segmented oceanic lithosphere. We interpret new and reprocessed multichannel seismic reflection profiles, and multibeam bathymetric data, to study the variability in tectonic processes along the entire convergent margin. In central and south Chile, where the trench contains thick turbidite infill, accretionary prisms, some 50–60 km wide, have developed. These prisms, however, are ephemeral and can be rapidly removed by high-relief, morphological features on the incoming oceanic plate. Where topographic barriers inhibit the transport of turbidites along the trench, sediment infill abruptly decreases to less than 1 km thick and is confined to a narrow zone at the trench axis. There, all sediment is subducted; the margin is extending by normal faulting and collapsing due to basal tectonic erosion. The transition from accretion to tectonic erosion occurs over short distances (a few tens of km) along the trench. In the turbidite-starved northern Chile trench, ~1 km of slope debris reaches the trench and is subsequently subducted. There, tectonic erosion is causing pronounced steepening of the margin, associated pervasive extension across the slope and into the emerged coastal area, and consequent collapse of the overriding plate. The volume of subducting material varies little along much of the margin. However, the composition of the material varies from slope debris of upper-plate fragments and material removed from the upper plate by basal erosion, to turbidites derived from the Andes.

Description: Results of geological, geomechanical and seismometric investigations aiming at the analysis of the seismic response in a carbonate ridge of the Nera River valley (Central Apennines – Italy) are discussed. Geological and geomechanical surveys were aimed at defining the stratigraphic and structural setting of the outcropping formations and the jointing conditions of the rock mass. Velocimetric records of both ambient noise and small-magnitude earthquakes were analysed in order to identify amplification conditions. The analysis was carried out in the time domain, through directional energy evaluation, and in the frequency domain, through H/V spectral ratios and spectral ratios with respect to a reference station. A local amplification factor was estimated from Housner intensity. The study revealed a significant seismic amplification in a fault zone. This effect was observed in intensely jointed and mylonitic rock masses, located inside moderately jointed rock masses, and is the result of specific geometries and significant impedance contrasts. A map of fault zones prone to amplification of ground motion was constructed, taking into account the jointing conditions of the rock masses and the structural setting of the investigated ridge. The study relied on an integrated methodological approach, which combined the available data under union and intersection criteria.

Description: Published

Description: 416-449

Description: JCR Journal

Description: reserved

Description: Scientific investigations in Antarctica are, for many different reasons, a challenging and fascinating task. Measurements, observations and field operations must be carefully planned well in advance and the capacity of successfully meeting the goals of a scientific project is often related to the capacity of forecasting and anticipating the many different potential mishaps. In order to do that, experience and logistic support are crucial. On the scientific side, the team must be aware of its tasks and be prepared to carry out observations in a hostile environment: both technology and human resources have to be suitably selected, prepared, tested and trained. On the logistic side, nations, institutions and any other organisation involved in the expeditions must ensure the proper amount of competence and practical support. The history of modern Italian Antarctic expeditions dates back to the middle 80’s when the first infrastructures of “Mario Zucchelli Station”, formerly Terra Nova Bay Station, were settled at Terra Nova Bay, Northern Victoria Land. Only a few years later, the first geodetic infrastructures were planned and built. Italian geodetic facilities and activities were, ever since, being constantly maintained and developed. Nowadays, the most remarkable geodetic infrastructures are the permanent Global Positioning System (GPS) station (TNB1) installed at Mario Zucchelli and the GPS geodetic network Victoria Land Network for DEFormation control (VLNDEF) entirely deployed on an area extending between 71° S and 76° S and 160° E and 170° E. These facilities do not only allow carrying out utmost geodetic investigations but also posses interesting capacities on the international multidisciplinary scientific scenario. In order to fully exploit their potentiality, management and maintenance of the infrastructure are crucial; nevertheless, in order to perform high quality scientific research, these abilities must be coupled with the knowledge concerning a proper use and a correct processing of the information that these infrastructures can provide. This work focuses on the different methods that can be applied to process the observations that are performed with GPS technique in Northern Victoria Land, aiming at reaching the highest accuracy of results and assuring the larger significance and versatility of the processing outcomes. Three software were used for the analysis, namely: Bernese v.5.0, Gipsy/Oasis II and Gamit/Globk. The working data sets are (i) the permanent GPS station TNB1 observations continuously performed since 1998 and (ii) the five episodic campaigns performed on the sites of VLNDEF. The two infrastructures can be regarded as neat examples of standard geodetic installation in Antarctica. Therefore, the technological solutions that were adopted and applied for establishing the GPS permanent station and the VLNDEF geodetic network as well as the data processing strategies and the data analysis procedures that were tested on their observation will be illustrated in detail. The results will be presented, compared and discussed. Furthermore, their potentials and role in geodetic research will be carefully described; their versatility will also be highlighted in the foreground of a multidisciplinary Antarctic international scientific activity.

Description: Published

Description: 37-72

Description: 1.8. Osservazioni di geofisica ambientale

Description: reserved

Description: © 2008 The Authors. This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. The definitive version was published in Nucleic Acids Research 36 (2008): 2522-2529, doi:10.1093/nar/gkm1166

Description: Penelope-like elements (PLEs) represent a new class of retroelements identified in more than 80 species belonging to at least 10 animal phyla. Penelope isolated from Drosophila virilis is the only known transpositionally active representative of this class. Although the size and structure of the Penelope major transcript has been previously described in both D. virilis and D. melanogaster transgenic strains, the architecture of the Penelope regulatory region remains unknown. In order to determine the localization of presumptive Penelope promoter and enhancer-like elements, segments of the putative Penelope regulatory region were linked to a CAT reporter gene and introduced into D. melanogaster by P-element-mediated transformation. The results obtained using ELISA to measure CAT expression levels and RNA studies, including RT–PCR, suggest that the active Penelope transposon contains an internal promoter similar to the TATA-less promoters of LINEs. The results also suggest that some of the Penelope regulatory sequences control the preferential expression in the ovaries of the adult flies by enhancing expression in the ovary and reducing expression in the carcass. The possible significance of the intron within Penelope for the function and evolution of PLEs, and the effect of Penelope insertions on adjacent genes, are discussed.

Description: This work was supported by grants from Russian Academy of Sciences (Cell and Molecular Biology to M.E.), and Welcome Trust Grant (075698) to M.E and D.J.F.

Description: This paper is not subject to U.S. copyright. The definitive version was published in ICES Journal of Marine Science: Journal du Conseil 67 (2010): 1-9, doi:10.1093/icesjms/fsp221.

Description: Effective marine ecosystem-based management (EBM) requires understanding the key processes and relationships controlling the aspects of biodiversity, productivity, and resilience to perturbations. Unfortunately, the scales, complexity, and non-linear dynamics that characterize marine ecosystems often confound managing for these properties. Nevertheless, scientifically derived decision-support tools (DSTs) are needed to account for impacts resulting from a variety of simultaneous human activities. Three possible methodologies for revealing mechanisms necessary to develop DSTs for EBM are: (i) controlled experimentation, (ii) iterative programmes of observation and modelling ("learning by doing"), and (iii) comparative ecosystem analysis. We have seen that controlled experiments are limited in capturing the complexity necessary to develop models of marine ecosystem dynamics with sufficient realism at appropriate scales. Iterative programmes of observation, model building, and assessment are useful for specific ecosystem issues but rarely lead to generally transferable products. Comparative ecosystem analyses may be the most effective, building on the first two by inferring ecosystem processes based on comparisons and contrasts of ecosystem response to human-induced factors. We propose a hierarchical system of ecosystem comparisons to include within-ecosystem comparisons (utilizing temporal and spatial changes in relation to human activities), within-ecosystem-type comparisons (e.g. coral reefs, temperate continental shelves, upwelling areas), and cross-ecosystem-type comparisons (e.g. coral reefs vs. boreal, terrestrial vs. marine ecosystems). Such a hierarchical comparative approach should lead to better understanding of the processes controlling biodiversity, productivity, and the resilience of marine ecosystems. In turn, better understanding of these processes will lead to the development of increasingly general laws, hypotheses, functional forms, governing equations, and broad interpretations of ecosystem responses to human activities, ultimately improving DSTs in support of EBM.

Description: © The Author 2006. This article is posted here by permission of Oxford University Press. The definitive version was published in Nucleic Acids Research 34 (2006): 1-9, doi:10.1093/nar/gkj405.

Description: The goal of this group project has been to coordinate and bring up-to-date information on all genes of Escherichia coli K-12. Annotation of the genome of an organism entails identification of genes, the boundaries of genes in terms of precise start and end sites, and description of the gene products. Known and predicted functions were assigned to each gene product on the basis of experimental evidence or sequence analysis. Since both kinds of evidence are constantly expanding, no annotation is complete at any moment in time. This is a snapshot analysis based on the most recent genome sequences of two E.coli K-12 bacteria. An accurate and up-to-date description of E.coli K-12 genes is of particular importance to the scientific community because experimentally determined properties of its gene products provide fundamental information for annotation of innumerable genes of other organisms. Availability of the complete genome sequence of two K-12 strains allows comparison of their genotypes and mutant status of alleles.

Description: © 2009 The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution Noncommercial License. The definitive version was published in Coral Reefs 28 (2009): 327-337, doi:10.1007/s00338-009-0466-z.

Description: Design and decision-making for marine protected areas (MPAs) on coral reefs require prediction of MPA effects with population models. Modeling of MPAs has shown how the persistence of metapopulations in systems of MPAs depends on the size and spacing of MPAs, and levels of fishing outside the MPAs. However, the pattern of demographic connectivity produced by larval dispersal is a key uncertainty in those modeling studies. The information required to assess population persistence is a dispersal matrix containing the fraction of larvae traveling to each location from each location, not just the current number of larvae exchanged among locations. Recent metapopulation modeling research with hypothetical dispersal matrices has shown how the spatial scale of dispersal, degree of advection versus diffusion, total larval output, and temporal and spatial variability in dispersal influence population persistence. Recent empirical studies using population genetics, parentage analysis, and geochemical and artificial marks in calcified structures have improved the understanding of dispersal. However, many such studies report current self-recruitment (locally produced settlement/settlement from elsewhere), which is not as directly useful as local retention (locally produced settlement/total locally released), which is a component of the dispersal matrix. Modeling of biophysical circulation with larval particle tracking can provide the required elements of dispersal matrices and assess their sensitivity to flows and larval behavior, but it requires more assumptions than direct empirical methods. To make rapid progress in understanding the scales and patterns of connectivity, greater communication between empiricists and population modelers will be needed. Empiricists need to focus more on identifying the characteristics of the dispersal matrix, while population modelers need to track and assimilate evolving empirical results.

Description: Work by CB Paris was supported by the National Science Foundation grant NSF-OCE 0550732. Work by M-A Coffroth and SR Thorrold was supported by the National Science Foundation grant NSF-OCE 0424688. Work by TL Shearer was supported by an International Cooperative Biodiversity Group grant R21 TW006662-01 from the Fogarty International Center at the National Institutes of Health.