A seismic refraction study of the earth’s crust beneath S. W. Britain

This thesis describes a seismic refraction project undertaken in south west Britain in November 1966, designed to investigate crustal structure associated with a granite batholith. The results and interpretation of the data collected are presented in the form of crustal structure sections along the three lines of shots. These results are then compared with those obtained in other areas of the British Isles and the geological implications are discussed, suggestions for the design of future crustal structure experiments based upon the experience gained in south west England are also included. Several methods of analysis have been employed. Least squares straight lines have been fitted to first arrival travel time data and time term analyses have been applied to the major phases thus identified. Amplitude and velocity filtering measurements have been made of both first and secondary arrivals. The importance of a large amplitude secondary arrival, identified as a supercritical reflection from the Moho, is emphasised and an explanation of its amplitude characteristics is provided in terms of a lower crust exhibiting a gradual increase of velocity with depth. The average crustal velocity along the line of the south west England peninsula and between Land's End and Brittany is about 6.1 km/sec with an upper crustal velocity of about 5.8 km/sec. The crust is about 27 to 28 km thick with an almost horizontal Moho and a sub-Moho P(_n) velocity of about 8.07 km/sec. The granite batholith of south west England extends to a depth of about 11 km beneath which the lower crust exhibits a gradual increase of velocity with depth. For the region between Land's End and Ireland there is some evidence for a higher P(_n) velocity and average crustal velocity with a dipping Moho such that the thickness of the crust beneath southern Ireland may be about 30 km

Determination of the nearest-neighbor interaction in VO2_2 via fractal dimension analysis

The Ising model is one of the simplest and most well-established concepts to simulate phase transformations in complex materials. However, its most central constant, the interaction strength J between two nearest neighbors, is hard to obtain. Here we show how this basic constant can be determined with a fractal dimension analysis of measured domain structures. We apply this approach to vanadium dioxide, a strongly correlated material with a first-order insulator-to-metal phase-transition with enigmatic properties. We obtain a nearest-neighbor interaction of 13.8 meV, a value close to the thermal energy at room temperature. Consequently, even far below the transition temperature, there are spontaneous local phase-flips from the insulating into the metallic phase. These fluctuations explain several measured anomalies in VO$_2$, in particular the low thermal carrier activation energy and the finite conductivity of the insulating phase. As a method, our fractal dimension analysis links the Ising model to macroscopic material constants for almost any first-order phase transition.Comment: {\dag}These authors contributed equally to this wor

Influence of AMPK and ROCK Inhibition on Contractile Responses in Isolated Carotid Arteries in Adult and Aged WKY and SHR Rats

AMP-activated protein kinase (AMPK) is emerging as an important regulator of vascular function and is proven to affect vascular tone. Here we investigate how AMPK inhibition in arteries from both young and aged normotensive Wistar Kyoto (WKY) and spontaneously hypertensive (SHR) rats affects contraction in response to different receptor agonists. In study 1, isolated common carotid artery (CCA) segments (denuded of endothelium) from WKY and SHR were used to determine vasomotor dose-responses to the alpha-adrenergic agonist phenylephrine (PE: 10-9.0 - 10-4.5 M) and to the thromboxane-prostanoid receptor agonist U46619 (10-9.0 – 10-6.0 M) after incubation with no drug (CON); the AMPK inhibitor compound C (CC; 20 µM); the rho-assosiated protein kinase (ROCK) inhibitor Y27632 (1 µM); or, a combination of CC and Y27632 at the same concentration. PE contraction was suppressed in all groups for all treatment conditions (CC, Y, CC+Y; P<0.05) with the combination condition (CC + Y) being significantly greater than either individual drug effect in both WKY and SHR CCA, though this effect was not completely additive in all groups. Vasomotor responses of CCA segments exposed to U46619 under the same incubation conditions exhibited significant increase in EC50 when compared to the CON within their respective groups, but no significant differences were found in the maximum developed tension (MAX; P<0.05). The greatest differences were found between the receptor-mediated responses to contraction, with CCA segments of all groups having a higher sensitivity to the TPr agonist U46619 than to the alpha-adrenergic agonist PE. Fold increase in EC50 was significantly greater in groups subject to PE-induced contraction compared to the same responses in U46619 treated groups, with the greatest increase being present in the young WKY (CC+Y; 13.0 ±3.5 fold increase vs. CON). Vasomotor responses were relatively unaffected by hypertension and age. In study 2, the vasomotor constriction response to separate and combined AMPK and/or HMG-CoA reductase inhibition was measured via dose-response curves to PE. Four curves were generated: CON; CC (20 µM); Simvastatin (SIM; 5 µM); and, CC + SIM. PE contraction was suppressed in all groups for all treatment conditions (CC, SIM, CC+SIM; P<0.05) with the combination condition being significantly greater than either individual drug effect. The results suggest that AMPK may contribute to modulating the PE contraction response in denuded CCA via RhoA/ROCK-dependent and –independent mechanisms

Characterization of the repertoire diversity of the Plasmodium falciparum stevor multigene family in laboratory and field isolates

BACKGROUND: The evasion of host immune response by the human malaria parasite Plasmodium falciparum has been linked to expression of a range of variable antigens on the infected erythrocyte surface. Several genes are potentially involved in this process with the var, rif and stevor multigene families being the most likely candidates and coding for rapidly evolving proteins. The high sequence diversity of proteins encoded by these gene families may have evolved as an immune evasion strategy that enables the parasite to establish long lasting chronic infections. Previous findings have shown that the hypervariable region (HVR) of STEVOR has significant sequence diversity both within as well as across different P. falciparum lines. However, these studies did not address whether or not there are ancestral stevor that can be found in different parasites. METHODS: DNA and RNA sequences analysis as well as phylogenetic approaches were used to analyse the stevor sequence repertoire and diversity in laboratory lines and Kilifi (Kenya) fresh isolates. RESULTS: Conserved stevor genes were identified in different P. falciparum isolates from different global locations. Consistent with previous studies, the HVR of the stevor gene family was found to be highly divergent both within and between isolates. Importantly phylogenetic analysis shows some clustering of stevor sequences both within a single parasite clone as well as across different parasite isolates. CONCLUSION: This indicates that the ancestral P. falciparum parasite genome already contained multiple stevor genes that have subsequently diversified further within the different P. falciparum populations. It also confirms that STEVOR is under strong selection pressure

Towards a Networks-of-Networks Framework for Cyber Security

Networks-of-networks (NoN) is a graph-theoretic model of interdependent networks that have distinct dynamics at each network (layer). By adding special edges to represent relationships between nodes in different layers, NoN provides a unified mechanism to study interdependent systems intertwined in a complex relationship. While NoN based models have been proposed for cyber-physical systems, in this position paper we build towards a three-layered NoN model for an enterprise cyber system. Each layer captures a different facet of a cyber system. We present in-depth discussion for four major graph- theoretic applications to demonstrate how the three-layered NoN model can be leveraged for continuous system monitoring and mission assurance.Comment: A shorter (3-page) version of this paper will appear in the Proceedings of the IEEE Intelligence and Security Informatics 2013, Seattle Washington, USA, June 4-7, 201

A Distributed System for Robot Manipulator Control, NSF Grant ECS-11879 Fourth Report

This is the fourth annual report representing our last year\u27s work under the current grant. This work was directed to the development of a distributed computer architecture to function as a force and motion server to a robot system. In the course of this work we developed a compliant contact sensor to provide for transitions between position and force control; developed an end-effector capable of securing a stable grasp on an object and a theory of grasping; developed and built a controller which minimizes control delays; explored a parallel kinematics algorithms for the controller; developed a consistent approach to the definition of motion both in joint coordinates and in Cartesian coordinates; developed a symbolic simplification software package to generate the dynamics equations of a manipulator such that the calculations may be split between background and foreground

mer-Bis[2-(1,3-benzothiazol-2-yl)phenyl-κ2 C 1,N][3-phenyl-5-(2-pyridyl)-1,2,4-triazol-1-ido-κ2 N 1,N 5]iridium(III) deuterochloro­form 3.5-solvate

In the title compound, [Ir(C13H9N4)(C13H8NS)2]·3.5CDCl3, the coordination at iridium is octa­hedral, but with narrow ligand bite angles. The bond lengths at iridium show the expected trans influence, with the Ir—N bonds trans to C being appreciably longer than those trans to N. The chelate rings are mutually perpendicular, the inter­planar angles between them all lying within 6° of 90°. All ligands are approximately planar; the maximum inter­planar angles within ligands are ca 10°. The three ordered deuterochloro­form mol­ecules are all involved in C⋯D—A contacts that can be inter­preted as hydrogen bonds of various types. The fourth deuterochloroform is disordered over an inversion centre