Molecular and serological analysis of herpesvirus infections in the immunocompromised host

There are eight described human herpesviruses. All share the ability to achieve latency in their host following primary infection and may subsequently reactivate later in life. In immunocompetent individuals herpesvirus infections, especially those caused by reactivating virus, are usually mild however in patients with impaired cellular immune function they may cause significant morbidity and mortality. In this thesis molecular and serological techniques were used to define the prevalence of the human herpesviruses in a variety of immunocompromised groups as these individuals are at greatest risk of severe herpesviral disease. Human herpesvirus 8 (HHV8) is the most recently discovered of the human herpesviruses. A nested polymerase chain reaction (PCR) for detecting HHV8 genome was designed and used to examine the association between infection with HHV8 and FIIV-associated Kaposi's sarcoma (KS). The prevalence of HHV8 genome carriage in the general UK population was defined, as were potential routes of HHV8 transmission. Novel treatments for HIV-KS were investigated. The value of herpesviral genome detection in predicting associated disease was evaluated, together with the genome load response of cytomegalovirus (CMV), a significant herpesviral pathogen, to a novel chemotherapeutic protocol for immunosuppressed patients receiving allogenic bone marrow transplantation. The prevalence and epidemiology of HHV8 were found to be compatible with that predicted for a causal agent of KS, but not the haematological malignancy multiple myeloma. Apart from 1-IHV8, Epstein-Barr virus and CMV were found to be the most significant herpesvirus pathogens in the immunocompromised host.. The use of molecular detection techniques, such as PCR, were shown to be of great value in the diagnostic and epidemiological determination of herpesviral infection in immunocompromised patients

Twisted supersymmetry and the topology of theory space

We present examples of four dimensional, non-supersymmetric field theories in which ultraviolet supersymmetry breaking effects, such as bose-fermi splittings and the vacuum energy, are suppressed by $(\alpha/4 \pi)^{N}$, where $\alpha$ is a weak coupling factor and $N$ can be made arbitrarily large. The particle content and interactions of these models are conveniently represented by a graph with sites and links, describing the gauge theory space structure. While the theories are supersymmetric ``locally'' in theory space, supersymmetry can be explicitly broken by topological obstructions.Comment: 9 pages, revtex

Vacuum polarization in two-dimensional static spacetimes and dimensional reduction

We obtain an analytic approximation for the effective action of a quantum scalar field in a general static two-dimensional spacetime. We apply this to the dilaton gravity model resulting from the spherical reduction of a massive, non-minimally coupled scalar field in the four-dimensional Schwarzschild geometry. Careful analysis near the event horizon shows the resulting two-dimensional system to be regular in the Hartle-Hawking state for general values of the field mass, coupling, and angular momentum, while at spatial infinity it reduces to a thermal gas at the black-hole temperature.Comment: REVTeX 4, 23 pages. Accepted by PRD. Minor modifications from original versio

Analytical approximation of the stress-energy tensor of a quantized scalar field in static spherically symmetric spacetimes

Analytical approximations for ${}$ and ${}$ of a quantized scalar field in static spherically symmetric spacetimes are obtained. The field is assumed to be both massive and massless, with an arbitrary coupling $\xi$ to the scalar curvature, and in a zero temperature vacuum state. The expressions for ${}$ and ${}$ are divided into low- and high-frequency parts. The contributions of the high-frequency modes to these quantities are calculated for an arbitrary quantum state. As an example, the low-frequency contributions to ${}$ and ${}$ are calculated in asymptotically flat spacetimes in a quantum state corresponding to the Minkowski vacuum (Boulware quantum state). The limits of the applicability of these approximations are discussed.Comment: revtex4, 17 pages; v2: three references adde

Reconstructing the 3-D Trajectories of CMEs in the Inner Heliosphere

A method for the full three-dimensional (3-D) reconstruction of the trajectories of coronal mass ejections (CMEs) using Solar TErrestrial RElations Observatory (STEREO) data is presented. Four CMEs that were simultaneously observed by the inner and outer coronagraphs (COR1 and 2) of the Ahead and Behind STEREO satellites were analysed. These observations were used to derive CME trajectories in 3-D out to ~15Rsun. The reconstructions using COR1/2 data support a radial propagation model. Assuming pseudo-radial propagation at large distances from the Sun (15-240Rsun), the CME positions were extrapolated into the Heliospheric Imager (HI) field-of-view. We estimated the CME velocities in the different fields-of-view. It was found that CMEs slower than the solar wind were accelerated, while CMEs faster than the solar wind were decelerated, with both tending to the solar wind velocity.Comment: 17 pages, 10 figures, 1 appendi

Put your own “oxygen mask” on first: A behavioral typology of leaders' self-care

OnlinePublOrganizational leaders are essential in implementing, interpreting, and even proactively initiating changes for human resource (HR) functions to enhance workplace productivity and well-being. However, recent studies have cautioned that providing positive and supportive leadership usually drains these organizational leaders. Although the literature has shed light on how leaders can use self-care strategies to recharge, researchers and HR professionals know relatively little about (1) what specific self-care actions leaders can take and (2) how external crises such as COVID-19 constrain leaders' selfcare actions. To identify specific leaders' self-care behaviors, which we refer to as oxygen masks, we interviewed 41 healthcare managers in Australia during the COVID-19 pandemic in 2020. We presented a behavioral typology summarizing distinct oxygen masks that leaders used at different points in time. These oxygen masks include improving physical well-being, improving emotional/spiritual/social well-being, fulfilling managerial roles, and seeking collegial and organizational support. Moreover, we concluded that the COVID-19 restrictions made some of these oxygen masks less accessible, negatively impacting leaders' well-being. Our research conclusions have implications for theory and future studies on extending the literature associated with leadership development, leaders' resilience, and leaders' well-being. The results also provide HR professionals with practical suggestions about assisting line managers in improving their self-care and sustaining their leadership effectiveness.Chia-Yen Chiu (Chad), Matylda Howard, Edilene Lopes, Carol T. Kulik, Michelle R. Tucke

Level-rank duality of the U(N) WZW model, Chern-Simons theory, and 2d qYM theory

We study the WZW, Chern-Simons, and 2d qYM theories with gauge group U(N). The U(N) WZW model is only well-defined for odd level K, and this model is shown to exhibit level-rank duality in a much simpler form than that for SU(N). The U(N) Chern-Simons theory on Seifert manifolds exhibits a similar duality, distinct from the level-rank duality of SU(N) Chern-Simons theory on S^3. When q = e^{2 pi i/(N+K)}, the observables of the 2d U(N) qYM theory can be expressed as a sum over a finite subset of U(N) representations. When N and K are odd, the qYM theory exhibits N K duality, provided q = e^{2 pi i/(N+K)} and theta = 0 mod 2 pi /(N+K).Comment: 19 pages; v2: minor typo corrected, 1 paragraph added, published versio

Fluid evolution in CM carbonaceous chondrites tracked through the oxygen isotopic compositions of carbonates

The oxygen isotopic compositions of calcite grains in four CM carbonaceous chondrites have been determined by NanoSIMS, and results reveal that aqueous solutions evolved in a similar manner between parent body regions with different intensities of aqueous alteration. Two types of calcite were identified in Murchison, Mighei, Cold Bokkeveld and LaPaz Icefield 031166 by differences in their petrographic properties and oxygen isotope values. Type 1 calcite occurs as small equant grains that formed by filling of pore spaces in meteorite matrices during the earliest stages of alteration. On average, the type 1 grains have a δ18O of ∼32–36‰ (VSMOW), and Δ17O of between ∼2‰ and −1‰. Most grains of type 2 calcite precipitated after type 1. They contain micropores and inclusions, and have replaced ferromagnesian silicate minerals. Type 2 calcite has an average δ18O of ∼21–24‰ (VSMOW) and a Δ17O of between ∼−1‰ and −3‰. Such consistent isotopic differences between the two calcite types show that they formed in discrete episodes and from solutions whose δ18O and δ17O values had changed by reaction with parent body silicates, as predicted by the closed-system model for aqueous alteration. Temperatures are likely to have increased over the timespan of calcite precipitation, possibly owing to exothermic serpentinisation. The most highly altered CM chondrites commonly contain dolomite in addition to calcite. Dolomite grains in two previously studied CM chondrites have a narrow range in δ18O (∼25–29‰ VSMOW), with Δ17O ∼−1‰ to −3‰. These grains are likely to have precipitated between types 1 and 2 calcite, and in response to a transient heating event and/or a brief increase in fluid magnesium/calcium ratios. In spite of this evidence for localised excursions in temperature and/or solution chemistry, the carbonate oxygen isotope record shows that fluid evolution was comparable between many parent body regions. The CM carbonaceous chondrites studied here therefore sample either several parent bodies with a very similar initial composition and evolution or, more probably, a single C-type asteroid

Survival-Time Distribution for Inelastic Collapse

In a recent publication [PRL {\bf 81}, 1142 (1998)] it was argued that a randomly forced particle which collides inelastically with a boundary can undergo inelastic collapse and come to rest in a finite time. Here we discuss the survival probability for the inelastic collapse transition. It is found that the collapse-time distribution behaves asymptotically as a power-law in time, and that the exponent governing this decay is non-universal. An approximate calculation of the collapse-time exponent confirms this behaviour and shows how inelastic collapse can be viewed as a generalised persistence phenomenon.Comment: 4 pages, RevTe