Cenozoic paleoceanographic changes of the South Pacific from seismic reflection data

The Thermohaline Circulation (THC) in the world oceans is closely coupled with earth climate. With reconstructions of past oceanic conditions and comparisons with past climate conditions this coupling can be better understood. This in turn allows to provide better boundary conditions on ocean-climate coupling for forecasting models. However, the paleoceanographic setup is far from being completely revealed. One of the largest areas of the world oceans poorly surveyed is the South Pacific Ocean. The present ocean currents that transport deep cold water into the South Pacific are the Antarctic Circumpolar Current (ACC) and two northward setting flows directly influenced by the ACC, the Deep Western Boundary Current (DWBC) or western limb close to New Zealand and an eastern limb above the western flank of the East Pacific Rise (EPR). Understanding changes of this current system is important for reconstructions of past climates and the Antarctic Glaciation history. At present the reconstructed paleoceanographic history of the South Pacific is limited to ACC and DWBC at the western margin of the Southwest Pacific Basin and only reveals changes back to the Eocene/Oligocene boundary. This thesis presents new multichannel seismic reflection data surveying two regions at the eastern and western margin in the Southwest Pacific Basin. The objective is the identification and characterization of deep current derived sediment deposits in the South Pacific. The investigation covers the whole Cenozoic and thus provides indications for paleoceanographic changes due to East Antarctic Ice Sheet build-up prior to 34 Ma. Furthermore the study helps to fill a data gap in the open Pacific Ocean between New Zealand and South America and presents the first evidence for paleoceanographic changes in this poorly explored area. East of New Zealand at the Bounty Trough mouth a sediment drift indicates the onset of a deep cold current originating from the South Pacific Ocean around the Cretaceous/Palaeocene boundary. This current prevailed until the establishment of the ACC around the Eocene/Oligocene boundary. A second sediment drift indicates a current modification due to climate cooling around 44 - 42 Ma occurs contemporaneously with first indications of an East Antarctic Ice Sheet. These results are the first hints on a deep cold current in the South Pacific Ocean before the Opening of the Tasmanian Gateway and thus support the hypotheses that an Antarctic Ice Sheet was present at that time. Since ~19 Ma the history of the ACC has been recorded by the sedimentary deposits at the western flank of the EPR and east of the Bounty Trough mouth. Close to the EPR (45 deg. S) the sedimentary cover suggests a weak bottom current flow allowing deposition that is followed by a bottom current intensification around 9 Ma. The stronger bottom current flow has continued until today. East of New Zealand seismic data and drilling results reveal a current that created a sediment drift between 19.5 Ma and 10 Ma followed by a 5.4 Ma long hiatus in deposition caused by bottom current intensification due to West Antarctic Ice Sheet build-up. Thus, both limbs of bottom current flow into the South Pacific show intensification at the same time that was probably caused by an intensified ACC. Although deposition close to New Zealand starts again around 5 Ma, the flow of the DWBC remained strong, which is also evident at the eastern limb. A higher sediment load due to upstream erosion of the DWBC caused further deposition. The sediment deposits seen in seismic profiles also suggest that a limb of the DWBC enters the Bounty Trough, which until present was only inferred from erosional structures at the Bounty Trough mouth. A new approach based on spectral analysis of Parasound sub-bottom profiler data was used to further quantify the extent of the DWBC in the Bounty Trough. Under the assumption that the 41 kyr obliquity cycle is related to DWBC changes, mapping of this cyclicity in Parasound data is used to show that the extent of the DWBC into the Bounty Trough is limited to 178.2 deg. E

Sequence signature analysis of chromosome identity in three Drosophila species

BACKGROUND: All eukaryotic organisms need to distinguish each of their chromosomes. A few protein complexes have been described that recognise entire, specific chromosomes, for instance dosage compensation complexes and the recently discovered autosome-specific Painting of Fourth (POF) protein in Drosophila. However, no sequences have been found that are chromosome-specific and distributed over the entire length of the respective chromosome. Here, we present a new, unbiased, exhaustive computational method that was used to probe three Drosophila genomes for chromosome-specific sequences. RESULTS: By combining genome annotations and cytological data with multivariate statistics related to three Drosophila genomes we found sequence signatures that distinguish Muller's F-elements (chromosome 4 in D. melanogaster) from all other chromosomes in Drosophila that are not attributable to differences in nucleotide composition, simple sequence repeats or repeated elements. Based on these signatures we identified complex motifs that are strongly overrepresented in the F-elements and found indications that the D. melanogaster motif may be involved in POF-binding to the F-element. In addition, the X-chromosomes of D. melanogaster and D. yakuba can be distinguished from the other chromosomes, albeit to a lesser extent. Surprisingly, the conservation of the F-element sequence signatures extends not only between species separated by approximately 55 Myr, but also linearly along the sequenced part of the F-elements. CONCLUSION: Our results suggest that chromosome-distinguishing features are not exclusive to the sex chromosomes, but are also present on at least one autosome (the F-element) in Drosophila

Approximate reasoning with fuzzy-syllogistic systems

The well known Aristotelian syllogistic system consists of 256 moods. We have found earlier that 136 moods are distinct in terms of equal truth ratios that range in τ=[0,1]. The truth ratio of a particular mood is calculated by relating the number of true and false syllogistic cases the mood matches. A mood with truth ratio is a fuzzy-syllogistic mood. The introduction of (n-1) fuzzy existential quantifiers extends the system to fuzzy-syllogistic systems nS, 1<n, of which every fuzzy-syllogistic mood can be interpreted as a vague inference with a generic truth ratio that is determined by its syllogistic structure. We experimentally introduce the logic of a fuzzy-syllogistic ontology reasoner that is based on the fuzzy-syllogistic systems nS. We further introduce a new concept, the relative truth ratio rτ=[0,1] that is calculated based on the cardinalities of the syllogistic cases

DETC2008-49526 PLATFORM STRATEGIES FOR A SUPPLIER IN THE AIRCRAFT ENGINE INDUSTRY

ABSTRACT The utilization of a platform strategy has become a competitive priority in many industries, most notably in the automotive industry. Naturally, many firms in other industries are adopting this strategy with different modifications and degrees of implementation. However, little research covers the application of platform development in a supplier and/or small batch production environment. The adaptation of a platform strategy in these settings, by a supplier in the aircraft engine industry, is the focal point of this paper. Based on platform development literature and the characteristics of the aircraft engine industry and the company studied advantages and hindrances for platform strategies have been ruled out. Interviews with involved people within the company studied have further clarified different perspectives on platforms and their possible utilization. Based on the analysis of collected information it is proposed that a possible platform strategy would include: a technology platform, incorporating general knowledge on core technology assets embodied in either humans, organizations, processes, information or methods; and a product platform, incorporating product specific elements that could be re-used when developing new components for a particular product line

Predicting clinical resistance prevalence using sewage metagenomic data

Antibiotic resistance surveillance through regional and up-to-date testing of clinical isolates is a foundation for implementing effective empirical treatment. Surveillance data also provides an overview of geographical and temporal changes that are invaluable for guiding interventions. Still, due to limited infrastructure and resources, clinical surveillance data is lacking in many parts of the world. Given that sewage is largely made up of human fecal bacteria from many people, sewage epidemiology could provide a cost-efficient strategy to partly fill the current gap in clinical surveillance of antibiotic resistance. Here we explored the potential of sewage metagenomic data to assess clinical antibiotic resistance prevalence using environmental and clinical surveillance data from across the world. The sewage resistome correlated to clinical surveillance data of invasive Escherichia coli isolates, but none of several tested approaches provided a sufficient resolution for clear discrimination between resistance towards different classes of antibiotics. However, in combination with socioeconomic data, the overall clinical resistance situation could be predicted with good precision. We conclude that analyses of bacterial genes in sewage could contribute to informing management of antibiotic resistance. Karkman et al. explore how well available global sewage metagenomic data can predict clinical resistance prevalence using different models. A combination of sewage metagenomic data with socioeconomic factors predicts overall clinical resistance well, but still has limited ability to discriminate between resistance to different classes of antibiotics.Peer reviewe