Viscous and inviscid nonlinear dynamics on an axisymmetric ferrofluid jet

In this thesis the dynamical properties of an axisymmetric ferrofluid jet are investigated. The flow is subject to the Rayleigh-Plateau instability. However, the ferrofluid is centred on a current carrying wire which produces an azimuthal magnetic field. Consequently, a super-critical magnetic field stabilises perturbations about the perfect cylinder solution but is unstable otherwise. The linearly stable regime is primarily investigated in the inviscid limit where long wave dynamics produce solitary wave structures. The dynamics of the ferrofluid are considered when either surrounded by a gas or a non-conducting fluid. The linearly unstable regime is investigated in the inviscid single-fluid and two-fluid regimes as well as in the viscous regime. In particular, the Kelvin-Helmholtz instability is investigated. Nonlinear dynamics and comparison with experimental findings are considered throughout all regimes. The nonlinear solitary wave structures show good comparison to both the theoretical and experimental literature. The nonlinear viscous regime produces static droplet chains that align with experimental findings in the literature. The final static state solutions are investigated numerically as well.Open Acces

The building pathology of early modern London

This thesis is an exploratory study into enteric complaints and respiratory ailments in early modern London between 1500 and 1720. These two diseases are closely associated with urban environments, especially domestic housing, and they killed significant numbers during the study period. Unlike the plague, these diseases were comparatively stable from year to year and this thesis argues that this was largely related to constant exposure to defective buildings. While research into the relationship between housing and health is problematic, mainly because the inadequacy of housing is invariably associated with other hardships, such as poor nutrition and hygiene, this thesis aims to overcome this obstacle by applying new tools borrowed from the modern discipline of building pathology. This offers a contextual definition of a building defect and identifies the fundamental requirements of healthful housing. Building pathology also draws attention to the interaction of the external environment with buildings; the climate of the study period imposed extreme demands on vulnerable buildings and their services. Although there were variations in the quality of buildings occupied by different sectors of the population, the demands of the climate were largely exogenous to economy and society. Applying building pathology analysis to early modern London identifies conditions that were conducive to the spread of enteric and respiratory diseases amongst the wealthy as well as the poor. The final part of the thesis considers the social epidemiology of enteric and respiratory diseases, that is locating them within communities, spatially and residentially defined and questions whether the study of economic or social groups in the context of these two specific diseases helps or hinders epidemiology

A survey of spinning test particle orbits in Kerr spacetime

We investigate the dynamics of the Papapetrou equations in Kerr spacetime. These equations provide a model for the motion of a relativistic spinning test particle orbiting a rotating (Kerr) black hole. We perform a thorough parameter space search for signs of chaotic dynamics by calculating the Lyapunov exponents for a large variety of initial conditions. We find that the Papapetrou equations admit many chaotic solutions, with the strongest chaos occurring in the case of eccentric orbits with pericenters close to the limit of stability against plunge into a maximally spinning Kerr black hole. Despite the presence of these chaotic solutions, we show that physically realistic solutions to the Papapetrou equations are not chaotic; in all cases, the chaotic solutions either do not correspond to realistic astrophysical systems, or involve a breakdown of the test-particle approximation leading to the Papapetrou equations (or both). As a result, the gravitational radiation from bodies spiraling into much more massive black holes (as detectable, for example, by LISA, the Laser Interferometer Space Antenna) should not exhibit any signs of chaos.Comment: Submitted to Phys. Rev. D. Follow-up to gr-qc/0210042. Figures are low-resolution in order to satisfy archive size constraints; a high-resolution version is available at http://www.michaelhartl.com/papers

High-Energy Astrophysics in the 2020s and Beyond

With each passing decade, we gain new appreciation for the dynamic, connected, and often violent nature of the Universe. This reality necessarily places the study of high-energy processes at the very heart of modern astrophysics. This White Paper illustrates the central role of high-energy astrophysics to some of the most pressing astrophysical problems of our time, the formation/evolution of galaxies, the origin of the heavy elements, star and planet formation, the emergence of life on exoplanets, and the search for new physics. We also highlight the new connections that are growing between astrophysicists and plasma physicists. We end with a discussion of the challenges that must be addressed to realize the potential of these connections, including the need for integrated planning across physics and astronomy programs in multiple agencies, and the need to foster the creativity and career aspirations of individual scientists in this era of large projects.Comment: Astro2020 White Paper submissio

The building pathology of early modern London

This thesis is an exploratory study into enteric complaints and respiratory ailments in early modern London between 1500 and 1720. These two diseases are closely associated with urban environments, especially domestic housing, and they killed significant numbers during the study period. Unlike the plague, these diseases were comparatively stable from year to year and this thesis argues that this was largely related to constant exposure to defective buildings. While research into the relationship between housing and health is problematic, mainly because the inadequacy of housing is invariably associated with other hardships, such as poor nutrition and hygiene, this thesis aims to overcome this obstacle by applying new tools borrowed from the modern discipline of building pathology. This offers a contextual definition of a building defect and identifies the fundamental requirements of healthful housing. Building pathology also draws attention to the interaction of the external environment with buildings; the climate of the study period imposed extreme demands on vulnerable buildings and their services. Although there were variations in the quality of buildings occupied by different sectors of the population, the demands of the climate were largely exogenous to economy and society. Applying building pathology analysis to early modern London identifies conditions that were conducive to the spread of enteric and respiratory diseases amongst the wealthy as well as the poor. The final part of the thesis considers the social epidemiology of enteric and respiratory diseases, that is locating them within communities, spatially and residentially defined and questions whether the study of economic or social groups in the context of these two specific diseases helps or hinders epidemiology

Predictors of Poor Outcomes in Critically Ill Adults with Hematologic Malignancy

Background. Patients with hematologic malignancy (HM) often require intensive care unit (ICU) admission due to organ failure through disease progression or treatment-related complications. Objective. To determine mortality and prognostic variables in adult patients with HM who were admitted to ICU. Methods. Structured chart review of all adult patients (age ≥ 18 years) with HM admitted to ICU of a Canadian tertiary care hospital between 2004 and 2014. Outcome measures included mortality (ICU, 30-day, 60-day, and 12-month). Logistic regression was performed to determine predictors of mortality. Results. Overall, there were 206 cases of HM admitted to the ICU during the study (mean age: 51.3 ± 13.6 years; 60% male). Median stay was 3 days, with 14.1% requiring prolonged ICU admission. ICU mortality was 45.6% and increased to 59.2% at 30 days, 62.6% at 60 days, and 74.3% at 12 months. Predictors of increased ICU mortality included mechanical ventilation requirement and vasopressor therapy requirement, while admission to ICU postoperatively and having myeloma were associated with decreased mortality. Conclusions. Patients admitted to ICU with HM have high mortality (45.6%), which increased to 74.3% at 1 year. Analysis of multiple variables identified critical illness, postsurgical admission, and myeloma as predictors of patient outcomes

Quantum computation and quantum simulation with ultracold molecules

Ultracold molecules confined in optical lattices or tweezer traps can be used to process quantum information and simulate the behaviour of many-body quantum systems. Molecules offer several advantages for these applications. They have a large set of stable states with strong transitions between them and long coherence times. Molecules can be prepared in a chosen state with high fidelity, and the state populations can be measured efficiently. Control over their long-range dipole–dipole interactions can enable the entanglement of pairs of molecules, generating interesting and technologically useful many-body states. This Review covers the advances made so far in the field of quantum simulation and computation with ultracold molecules and the challenges still to overcome

Lifetime cardiovascular management of patients with previous Kawasaki disease.

Kawasaki disease (KD) is an inflammatory disorder of young children, associated with vasculitis of the coronary arteries with subsequent aneurysm formation in up to one-third of untreated patients. Those who develop aneurysms are at life-long risk of coronary thrombosis or the development of stenotic lesions, which may lead to myocardial ischaemia, infarction or death. The incidence of KD is increasing worldwide, and in more economically developed countries, KD is now the most common cause of acquired heart disease in children. However, many clinicians in the UK are unaware of the disorder and its long-term cardiac complications, potentially leading to late diagnosis, delayed treatment and poorer outcomes. Increasing numbers of patients who suffered KD in childhood are transitioning to the care of adult services where there is significantly less awareness and experience of the condition than in paediatric services. The aim of this document is to provide guidance on the long-term management of patients who have vascular complications of KD and guidance on the emergency management of acute coronary complications. Guidance on the management of acute KD is published elsewhere

The Mock LISA Data Challenges: from Challenge 3 to Challenge 4

The Mock LISA Data Challenges are a program to demonstrate LISA data-analysis capabilities and to encourage their development. Each round of challenges consists of one or more datasets containing simulated instrument noise and gravitational waves from sources of undisclosed parameters. Participants analyze the datasets and report best-fit solutions for the source parameters. Here we present the results of the third challenge, issued in Apr 2008, which demonstrated the positive recovery of signals from chirping Galactic binaries, from spinning supermassive--black-hole binaries (with optimal SNRs between ~ 10 and 2000), from simultaneous extreme-mass-ratio inspirals (SNRs of 10-50), from cosmic-string-cusp bursts (SNRs of 10-100), and from a relatively loud isotropic background with Omega_gw(f) ~ 10^-11, slightly below the LISA instrument noise.Comment: 12 pages, 2 figures, proceedings of the 8th Edoardo Amaldi Conference on Gravitational Waves, New York, June 21-26, 200