Micro-cracks, which develop during the service life of reinforced concrete structures, reduce the durability of concrete through the penetration of fluids. Microbially-induced calcium carbonate precipitation (MICP) occurs naturally in the presence of ureolytic bacteria which precipitate calcium carbonate (CaCO 3) through urea hydrolysis. This deposition leads to the filling of micro-cracks and sealing of pores, reducing ingress of fluids into the concrete. The research aims were to assess the potential of Lysinibacillus sphaericus for healing cracks in concrete and to study the effects of this treatment on the absorption properties of treated concrete. Lysinibacillus sphaericus was cultivated in vitro and induction of MICP through urea hydrolysis was tested on cement paste with two different calcium sources. The calcium precipitates where characterized by light microscopy, Scanning Electron Microscopy, Energy Dispersive Spectroscopy and Fourier Transform Infrared Spectroscopy. The final phase of the study involved testing of the crack healing capacity and the effect on absorption of the MICP process on mortar samples. These parameters were measured by means of visual examinations, light and digital microscopy, Ultrasonic Pulse Velocity (UPV), and absorption tests. The study confirmed that MICP is induced successfully on concrete using Lysinibacillus sphaericus. Samples exposed to repeated treatment cycles of Lysinibacillus sphaericus in the presence of a calcium source, exhibited a more extensive and even coating of CaCO 3 crystals on the surface confirming that repeated cycles of treatment are more effective in increasing the amount of CaCO 3 deposition and therefore increasing crack healing capacity. Digital microscopy and UPV analysis proved that this precipitate was successful in partially healing cracks in samples. Sorptivity tests confirmed this and showed that it was also successful as a surface treatment to reduce absorption.

In this work, we identify a problem with the process of volume-to-surface mapping of functional Magnetic Resonance Imaging (fMRI) data that emerges in local connectivity analysis. We show that neighborhood correlations on the surface of the brain vary spatially with the gyral structure, even when the underlying volumetric data are uncorrelated noise. This could potentially have impacted studies focusing upon local neighborhood connectivity. We explore the effects of this anomaly across varying data resolutions and surface mesh densities, and propose several measures to mitigate these unwanted effects.

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The early life environment programmes cortical architecture and cognition across the life course. A measure of cortical organisation that integrates information from multi-modal MRI and is unbound by arbitrary parcellations has proven elusive, which hampers efforts to uncover the perinatal origins of cortical health. Here, we use the Vogt-Bailey index to provide a fine-grained description of regional homogeneities and sharp variations in cortical microstructure based on feature gradients, and we investigate the impact of being born preterm on cortical development. Preterm infants have a homogeneous microstructure in temporal and occipital lobes, and the medial parietal, cingulate, and frontal cortices, compared with term infants. These observations replicated across two independent datasets and were robust to differences that remain in the data after matching samples and alignment of processing and quality control strategies. We conclude that cortical microstructural architecture is altered in preterm infants in a spatially distributed rather than localised fashion.

Starting from a Geometrothermodynamics metric for the space of thermodynamic equilibrium states in the mass representation, we use numerical techniques to analyse the thermodynamic geodesics of a supermassive Reissner Nordström black hole in isolation. Appropriate constraints are obtained by taking into account the processes of Hawking radiation and Schwinger pair-production. We model the black hole in line with the work of Hiscock and Weems [1]. It can be deduced that the relation which the geodesics establish between the entropy S and electric charge Q of the black hole extremises changes in the black hole's mass. Indeed, the expression for the entropy of an extremal black hole is an exact solution to the geodesic equation. We also find that in certain cases, the geodesics describe the evolution brought about by the constant emission of Hawking radiation and charged-particle pairs. arXiv:1609.07992v2 [gr-qc]