Antimicrobial Susceptibility of Listeria Species from Abattoir Effluent in Port Harcourt, Nigeria.

Untreated abattoir effluent constitutes a reservoir for the spread of important pathogens including Listeria monocytogenes, the etiologic agent of listeriosis. This study investigated the presence and antimicrobial resistance profile of Listeria species from abattoir effluent in some Port Harcourt communities using standard conventional and molecular methods. Listeria were detected in 26% of the samples examined. The resulting isolates were identified as L. grayi (53.85%), L. welshimeri (38.46%) and L. innocua (7.69%). The Listeria isolates showed varying resistance to cotrimoxazole (44.2%), chloramphenicol (34.6%), tetracycline (46.2%), streptomycin (75%), augmentin (94.2%), gentamycin (19.2%), erythromycin (34.6%) and cloxacillin (100%). All three disinfectants were not effective against Listeria species at concentrations of 12% and 25%. At 50% and 100% disinfectant concentration, dettol was the most effective followed by JIK and lastly, izal. The presence of Listeria species in abattoir effluent and levels of resistance to commonly used antibiotic and disinfectants portends danger to animals and human population hence the need for adequate treatment of effluent before discharged into the environment

Memristive Bauelemente für neuronale Schaltungen

The present post-doctoral thesis covers 14 original publications, which result from my work as research assistant between 2011 and 2015 at the Institute of electrical engineering at the technical faculty of the Christian-Albrecht university at Kiel. During this time my research work was strongly guided by the question how to understand memory and learning in brains and how we can build up non-biological systems, which function similar to those. In particular, I focused on the usage of new non-volatile memory technologies and electronic circuits for neuromorphic systems. Thus, the development of non-volatile devices and electronic circuits as well as biological models based on those devices is at the heart of this post-doctoral thesis

Three-dimensional (3-D) seismic imaging of conduits and radial faults associated with hydrothermal vent complexes (Vøring Basin, Offshore Norway)

Here, we document a suite of radial faults associated with hydrothermal vent complexes in the Vøring Basin, offshore Norway. These complexes have pyramid-shaped, cylindrical- and conical-shaped conduits, with a dome-, or eye-shaped morphology at their summit, intruding on Paleogene sedimentary rocks. Hydrothermal vents are intimate with the tips of magmatic sills that were emplaced at depths ranging between 1800 and 5800 ms Two Way Travel Time (TWTT). At shallower depths of 1800 to 3000 ms TWTT and intermediate depths of 3000 to 5000 ms TWWT, magmatic sills regularly intersect the lower parts of the vent conduits, which are characterized here as pipes. An important parameter that is used to characterize the morphology of a hydrothermal vent conduit is the width of the conduit, which is defined as the longest axis marking the extent of the vents' conduit within the surrounding host-rock strata. Our findings reveal that radial faults are commonly associated with the summits of hydrothermal vents, implying the existence of local stress fields around the vents, where the maximum compressive stress is radial and minimum stress is circumferential, which overrides the regional stress field and indicate variable stress regimes as opposed to tectonic faults. Importantly, circumferential stretching due to catastrophic plumbing of hydrothermal fluids, differential compaction and intensive fracturing enabled the polygonal faults to realign in a radial pattern resulting in the formation of radial faults at the vent summit. As a corollary of this work, we hypothesize that pyramid-shaped hydrothermal conduits are possibly markers of protracted sill emplacement in sedimentary basins

Geomorphological characterization of basal flow markers during recurrent mass movement: A case study from the Taranaki Basin, offshore New Zealand

This work examines the mode of basal to substrate interaction, and flow dynamics of recurrent mass wasting events from a high‐quality 3D seismic reflection data. The Taranaki Basin, offshore New Zealand offers a unique environment to understand these processes, as the Neogene succession of the area preserves vertical stacks of mass transport deposits (MTDs) from the Miocene to Pliocene. The approach used here combines seismic interpretation of the basal shear zones (BSZ) of the MTD, seismic attribute analyses, and colour rendering of both RMS amplitude and energy gradient maps. The five mass transport deposits are characterized into blocky‐MTDs consisting of moderate to high amplitude and variably deformed rafted blocks, and chaotic masses composed of slides and debris flow deposits. Classic examples of kinematic indicators at the BSZ of the MTDs akin to free‐slip flow processes such as liquefaction, hydroplaning, and shear wetting are convolute flow fabrics and basal shear zone cut‐offs (fractures). Striations, grooves, mega scours, U‐ and V‐shaped scours, substrate erosion, monkey fingers (peel backs), substrate deformation and shearing are associated with no‐slip flows, suggesting that the mass movements efficiently interacted with the underlying substrate. Importantly, the intersection of different kinematic indicators along the BSZs of all the MTDs suggests an overlap of flow regimes, flow overprinting and transformation during mass movement. Although basal tooling by rafted blocks seem dominant during remobilization of the blocky MTDs, the presence of other kinematic indicators signifies combined mechanisms involving both free‐flow and no‐slip processes during their translation. The classification scheme evaluated here innovatively shows mass movements habitually occur through a combination of flow mechanism rather than an independent flow regime

Giant paleo-seafloor craters and mass wasting associated with magma-induced uplift of the upper crust

Giant seafloor craters are known along many a continental margin with recurrent mass-wasting deposits. However, the impact of breakup-related magmatism on the evolution of such craters is barely understood. Using high-quality geophysical datasets, this work examines the genetic relationship among the location of magmatic sills, forced folds and the formation of giant paleo-seafloor craters underneath an ancient mass-transport complex in the Møre and Vøring basins, offshore Norway. The data reveal that forced folding of near-seafloor strata occurred because of the intrusion of several interconnected magmatic sills. Estimates of 1-dimensional uplift based on well data show that uplift occurred due to the intrusion of magma in Upper Cretaceous to Lower Eocene strata. Our findings also prove that subsurface fluid plumbing associated with the magmatic sills was prolonged in time and led to the development of several vertical fluid flow conduits, some of which triggered mass wasting in Neogene to Recent times. The repeated vertical expulsion of subsurface fluids weakened the strata on the continental slope, thereby promoting mass wasting, the selective cannibalization of the paleo-seafloor, and the formation of elongated craters at the basal shear zone of the mass-transport complex. Significantly, the model presented here proves a close link between subsurface magmatic plumbing systems and mass wasting on continental margins.</p

First evidence of (paleo)pockmarks in the Bass Strait, offshore SE Australia: A forced regression modulated shallow plumbing system

Pockmarks are morphological expressions of seabed fluid escape along continental margins. Identifying the underlying controls on their formation and spatial distribution is crucial for understanding substrate fluid plumbing systems and has important implications for hydrocarbon exploration, seafloor stability and seabed release of greenhouse gasses. Here, we use 3D seismic reflection dataset and a machine learning approach to present the first evidence for paleo-pockmarks in the Bass Strait, southeast Australia. The paleo-pockmarks are identified in the Bass Basin, within an interval between 250 and 310 m below present-day seafloor, corresponding to the Miocene carbonate-dominated Torquay Group. The paleo-pockmarks have depths ranging from ∼29 to 74 m and areas between ∼0.01 and 0.8 km2, with diameters varying between ∼0.1 and 1.1 km. The absence of an underlying seal-bypass system such as pipes and faults associated with these paleo-pockmarks discounts a deeper thermogenic source or a potential magmatic-driven fluid system. Rather a biogenic fluid system derived from the degradation of organic-rich layers and pore water expelled during early-stage compaction is hypothesised to drive paleo-pockmark formation. The seismic interval comprising these paleo-pockmarks demonstrates a distinctive seaward progradation and stepping-down configuration, indicating a forced regression. We propose this resulted in the destabilization of hydrostatic pressure triggering the creation of the paleo-pockmarks