Post-Caledonian Brittle Fault Zones on the Hyperextended SW Barents Sea Margin: New Insights into Onshore and Offshore Margin Architecture

Onshore-offshore correlation of brittle faults and tectonic lineaments has been undertaken along the SW Barents Sea margin off northern Norway. The study has focused on onshore mapping of fault zones, the mapping of offshore fault complexes and associated basins from seismic interpretation, and the linkage of fault complexes onshore and offshore by integrating a high-resolution DEM, covering both onshore and offshore portions of the study area, and processed magnetic anomaly data. This study shows that both onshore and offshore brittle faults manifest themselves mainly as alternating NNE–SSW- and ENE–WSW-trending, steeply to moderately dipping, normal fault zones constituting at least two major NE-SW-trending fault complexes, the Troms-Finnmark and Vestfjorden-Vanna fault complexes. These fault complexes in western Troms bound a major basement horst (the West Troms Basement Complex), run partly onshore and offshore and link up with the offshore Nysleppen and Måsøy fault complexes. Pre-existing structures in the basement, such as foliation, lithological boundaries and ductile shear zones are shown, at least on a local scale, to have exerted a controlling effect on faulting. On a larger scale, at least two major transfer fault zone systems, one along the reactivated Precambrian Senja Shear Belt and the other, the Fugløya transfer zone, accommodate changes in brittle fault polarity along the margin. Our results suggest that distributed rifting during Carboniferous and Late Permian/Early Triassic time was followed by a northwestward localisation of displacement to the Troms–Finnmark and Ringvassøy–Loppa fault complexes during the Late Jurassic/Early Cretaceous, resulting in the formation of a short-tapered, hyperextended margin with final break-up at ~55 Ma. An uplift of the margin and preservation of the West Troms Basement Complex as a basement outlier is suggested to be due to unloading and crustal flexure of the short-tapered margin in the region

Communication: The Rosenfeld-Tarazona expression for liquids’ specific heat:A numerical investigation of eighteen systems

We investigate the accuracy of the expression of Rosenfeld and Tarazona (RT) for the excess isochoric heat capacity, C_V^{ex} \propto T^{-2/5}, for eighteen model liquids. Previous investigations have reported no unifying features of breakdown for the RT expression. Here liquids with different stoichiometric composition, molecular topology, chemical interactions, degree of undercooling, and environment are investigated. We find that the RT expression is a better approximation for liquids with strong correlations between equilibrium fluctuations of virial and potential energy, i.e., Roskilde simple liquids [Ingebrigtsen et al., Phys. Rev. X 2, 011011 (2012)]. This observation holds even for molecular liquids under severe nanoscale confinement, the physics of which is completely different from the original RT bulk hard-sphere fluid arguments. The density dependence of the specific heat is predicted from the isomorph theory for Roskilde simple liquids, which in combination with the RT expression provides a complete description of the specific heat's density and temperature dependence.Comment: 6 page

Isomorphs in model molecular liquids

Isomorphs are curves in the phase diagram along which a number of static and dynamic quantities are invariant in reduced units. A liquid has good isomorphs if and only if it is strongly correlating, i.e., the equilibrium virial/potential energy fluctuations are more than 90% correlated in the NVT ensemble. This paper generalizes isomorphs to liquids composed of rigid molecules and study the isomorphs of two systems of small rigid molecules, the asymmetric dumbbell model and the Lewis-Wahnstrom OTP model. In particular, for both systems we find that the isochoric heat capacity, the excess entropy, the reduced molecular center-of-mass self part of the intermediate scattering function, the reduced molecular center-of-mass radial distribution function to a good approximation are invariant along an isomorph. In agreement with theory, we also find that an instantaneous change of temperature and density from an equilibrated state point to another isomorphic state point leads to no relaxation. The isomorphs of the Lewis-Wahnstrom OTP model were found to be more approximative than those of the asymmetric dumbbell model, which is consistent with the OTP model being less strongly correlating. For both models we find "master isomorphs", i.e., isomorphs have identical shape in the virial/potential energy phase diagram.Comment: 20 page

Excess-entropy scaling in supercooled binary mixtures

Supercooled liquids near the glass transition show remarkable non-Arrhenius transport phenomena, whose origin is yet to be clarified. Here, the authors use GPU molecular dynamics simulations for various binary mixtures in the supercooled regime to show the validity of a quasiuniversal excess-entropy scaling relation for viscosity and diffusion

Nonlinear acousto-electric transport in a two-dimensional electron system

We study both theoretically and experimentally the nonlinear interaction between an intense surface acoustic wave and a two-dimensional electron plasma in semiconductor-piezocrystal hybrid structures. The experiments on hybrid systems exhibit strongly nonlinear acousto-electric effects. The plasma turns into moving electron stripes, the acousto-electric current reaches its maximum, and the sound absorption strongly decreases. To describe the nonlinear phenomena, we develop a coupled-amplitude method for a two-dimensional system in the strongly nonlinear regime of interaction. At low electron densities the absorption coefficient decreases with increasing sound intensity, whereas at high electron density the absorption coefficient is not a monotonous function of the sound intensity. High-harmonic generation coefficients as a function of the sound intensity have a nontrivial behavior. Theory and experiment are found to be in a good agreement.Comment: 27 pages, 6 figure

Would loss to follow-up bias the outcome evaluation of patients operated for degenerative disorders of the lumbar spine?: A study of responding and non-responding cohort participants from a clinical spine surgery registry

Loss to follow-up may bias the outcome assessments of clinical registries. In this study, we wanted to determine whether outcomes were different in responding and non-responding patients who were included in a clinical spine surgery registry, at two years of follow-up. In addition, we wanted to identify risk factors for failure to respond. 633 patients who were operated for degenerative disorders of the lumbar spine were followed for 2 years using a local clinical spine registry. Those who did not attend the clinic and those who did not answer a postal questionnaire—for whom 2 years of outcome data were missing—and who would be lost to follow-up according to the standard procedures of the registry protocols, were defined as non-respondents. They were traced and interviewed by telephone. Outcome measures were: improvement in health-related quality of life (EQ-5D), leg pain, and back pain; and also general state of health, employment status, and perceived benefits of the operation. We found no statistically significant differences in outcome between respondents (78% of the patients) and nonrespondents (22%). Receipt of postal questionnaires (not being summoned for a follow-up visit) was the strongest risk factor for failure to respond. Forgetfulness appeared to be an important cause. Older patients and those who had complications were more likely to respond. Interpretation A loss to follow-up of 22% would not bias conclusions about overall treatment effects and, importantly, there were no indications of worse outcomes in non-respondents

Does the principle of minimum work apply at the carotid bifurcation: a retrospective cohort study

<p>Abstract</p> <p>Background</p> <p>There is recent interest in the role of carotid bifurcation anatomy, geometry and hemodynamic factors in the pathogenesis of carotid artery atherosclerosis. Certain anatomical and geometric configurations at the carotid bifurcation have been linked to disturbed flow. It has been proposed that vascular dimensions are selected to minimize energy required to maintain blood flow, and that this occurs when an exponent of 3 relates the radii of parent and daughter arteries. We evaluate whether the dimensions of bifurcation of the extracranial carotid artery follow this principle of minimum work.</p> <p>Methods</p> <p>This study involved subjects who had computed tomographic angiography (CTA) at our institution between 2006 and 2007. Radii of the common, internal and external carotid arteries were determined. The exponent was determined for individual bifurcations using numerical methods and for the sample using nonlinear regression.</p> <p>Results</p> <p>Mean age for 45 participants was 56.9 ± 16.5 years with 26 males. Prevalence of vascular risk factors was: hypertension-48%, smoking-23%, diabetes-16.7%, hyperlipidemia-51%, ischemic heart disease-18.7%.</p> <p>The value of the exponent ranged from 1.3 to 1.6, depending on estimation methodology.</p> <p>Conclusions</p> <p>The principle of minimum work (defined by an exponent of 3) may not apply at the carotid bifurcation. Additional factors may play a role in the relationship between the radii of the parent and daughter vessels.</p

Understanding practice: the factors that influence management of mild traumatic brain injury in the emergency department-a qualitative study using the Theoretical Domains Framework

Background: Mild traumatic brain injury is a frequent cause of presentation to emergency departments. Despite the availability of clinical practice guidelines in this area, there is variation in practice. One of the aims of the Neurotrauma Evidence Translation program is to develop and evaluate a targeted, theory- and evidence-informed intervention to improve the management of mild traumatic brain injury in Australian emergency departments. This study is the first step in the intervention development process and uses the Theoretical Domains Framework to explore the factors perceived to influence the uptake of four key evidence-based recommended practices for managing mild traumatic brain injury. Methods: Semi-structured interviews were conducted with emergency staff in the Australian state of Victoria. The interview guide was developed using the Theoretical Domains Framework to explore current practice and to identify the factors perceived to influence practice. Two researchers coded the interview transcripts using thematic content analysis. Results: A total of 42 participants (9 Directors, 20 doctors and 13 nurses) were interviewed over a seven-month period. The results suggested that (i) the prospective assessment of post-traumatic amnesia was influenced by: knowledge; beliefs about consequences; environmental context and resources; skills; social/professional role and identity; and beliefs about capabilities; (ii) the use of guideline-developed criteria or decision rules to inform the appropriate use of a CT scan was influenced by: knowledge; beliefs about consequences; environmental context and resources; memory, attention and decision processes; beliefs about capabilities; social influences; skills and behavioral regulation; (iii) providing verbal and written patient information on discharge was influenced by: beliefs about consequences; environmental context and resources; memory, attention and decision processes; social/professional role and identity; and knowledge; (iv) the practice of providing brief, routine follow-up on discharge was influenced by: environmental context and resources; social/professional role and identity; knowledge; beliefs about consequences; and motivation and goals. Conclusions: Using the Theoretical Domains Framework, factors thought to influence the management of mild traumatic brain injury in the emergency department were identified. These factors present theoretically based targets for a future intervention