On the diffuse interstellar bands and the local interstellar medium

This thesis presents results from four different studies on the diffuse interstellar bands and the local interstellar medium. Firstly, a detailed investigation into the profile of the λ6614 diffuse interstellar band (DIB) is presented, which was aimed at ascertaining the origin of the observed fine structure and overall band shape, and why both of these properties change between a number of different lines-of-sight. A new method for normalising DIBs is described, and revealed new information about how the λ6614 band evolves between lines-of-sight. Observations and modelling of the DIB profile towards HD 147889 suggests that this line-of-sight has the highest internal excitation of the carrier, which accounts for its greater width and additional structure. As a continuation of this project, a further fifteen DIB profiles were examined towards HD 179406 and HD 147889, some of which are thought to correlate with the column density of the C2 molecule. It was shown that HD 179406 and HD 147889 demonstrated almost identical band profiles for the ‘C2’ DIBs, which differed considerably to the ‘non-C2’ DIBs investigated in this study. Analysis presented in this chapter strongly supports the idea that the ‘C2’ DIBs form a distinct class, and the normalisation method used provides a new criterion for validating whether a DIB may be classed as a ‘C2’ DIB. A study of small-scale structure in the ultraviolet (UV) region towards three stars within the ρ Ophiuchus system was undertaken using observations from the Hubble Space Telescope, to deduce column densities of atomic and molecular species, and to obtain physical parameters such as density and kinetic temperature through chemical modelling. The biggest absorption differences were found within the C2 molecule profile, and it was found that the medium in which C2 molecules reside is denser towards ρ Oph A and ρ Oph B than ρ Oph D. Modelling additional species, such as Fe I and Fe II which are also thought to be present in the data, may help to further characterise the ISM towards these three stars. Optical and near-infrared (IR) observations of Herschel 36 were undertaken using the Southern African Large Telescope (SALT) and Gemini North. The aim of this project was to investigate the full DIB spectrum along this unusual sight-line, and determine how many DIBs were present and how many demonstrate the behaviour previously observed. A number of issues arose with the optical observations and the data reduction processes, meaning that the overall aim was not fully realised. However, observations from Gemini North showed more promise but did not detect either near-IR DIB, although higher S/N observations are recommended to verify their absence

Human aquaporins: regulators of transcellular water flow

Background: Emerging evidence supports the view that (AQP) aquaporin water channels are regulators of transcellular water flow. Consistentwith their expression in most tissues, AQPs are associatedwith diverse physiological and pathophysiological processes. Scope of review: AQP knockout studies suggest that the regulatory role of AQPs, rather than their action as passive channels, is their critical function. Transport through all AQPs occurs by a common passive mechanism, but their regulation and cellular distribution varies significantly depending on cell and tissue type; the role of AQPs in cell volumeregulation (CVR) is particularly notable. This reviewexamines the regulatory role of AQPs in transcellular water flow, especially in CVR.We focus on key systems of the human body, encompassing processes as diverse as urine concentration in the kidney to clearance of brain oedema. Major conclusions: AQPs are crucial for the regulation of water homeostasis, providing selective pores for the rapidmovement ofwater across diverse cellmembranes and playing regulatory roles in CVR. Gatingmechanisms have been proposed for human AQPs, but have only been reported for plant andmicrobial AQPs. Consequently, it is likely that the distribution and abundance of AQPs in a particular membrane is the determinant of membrane water permeability and a regulator of transcellular water flow. General significance: Elucidating the mechanisms that regulate transcellular water flow will improve our understanding of the human body in health and disease. The central role of specific AQPs in regulating water homeostasis will provide routes to a range of novel therapies. This article is part of a Special Issue entitled Aquaporins

150,000-year palaeoclimate record from northern Ethiopia supports early, multiple dispersals of modern humans from Africa

Climatic change is widely acknowledged to have played a role in the dispersal of modern humans out of Africa, but the timing is contentious. Dispersal is often linked to climatic change at ~60,000 years ago, despite increasing evidence for earlier presence of modern humans in Asia. Here we report a deep seismic and near-continuous core record of the last 150,000 years from Lake Tana in the Ethiopian highlands, close to the earliest modern human fossil sites and to postulated dispersal routes. The record shows varied climate at the end of the penultimate glacial, followed by an abrupt change to relatively stable moist climate during the last interglacial. These conditions would have favored population growth and range expansion, supporting models of early, multiple dispersals of modern humans from AfricapublishersversionPeer reviewe

Don’t turn your back on the symptoms of psychosis : a proof-of-principle, quasi-experimental public health trial to reduce the duration of untreated psychosis in Birmingham, UK

Background: Reducing the duration of untreated psychosis (DUP) is an aspiration of international guidelines for first episode psychosis; however, public health initiatives have met with mixed results. Systematic reviews suggest that greater focus on the sources of delay within care pathways, (which will vary between healthcare settings) is needed to achieve sustainable reductions in DUP (BJP 198: 256-263; 2011). Methods/Design: A quasi-experimental trial, comparing a targeted intervention area with a ‘detection as usual’ area in the same city. A proof-of–principle trial, no a priori assumptions are made regarding effect size; key outcome will be an estimate of the potential effect size for a definitive trial. DUP and number of new cases will be collected over an 18-month period in target and control areas and compared; historical data on DUP collected in both areas over the previous three years, will serve as a benchmark. The intervention will focus on reducing two significant DUP component delays within the overall care pathway: delays within the mental health service and help-seeking delay. Discussion: This pragmatic trial will be the first to target known delays within the care pathway for those with a first episode of psychosis. If successful, this will provide a generalizable methodology that can be implemented in a variety of healthcare contexts with differing sources of delay. Trial registration: http://www.controlled-trials.com/ISRCTN45058713 Keywords: Public mental health campaign, First-episode psychosis, Early detection, Duration of untreated psychosis, Youth mental healt

Could Public Restrooms Be an Environment for Bacterial Resistomes?

PMCID: PMC3547874This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

The Seroepidemiology of Haemophilus influenzae Type B Prior to Introduction of an Immunization Programme in Kathmandu, Nepal.

Haemophilus influenzae type b (Hib) is now recognized as an important pathogen in Asia. To evaluate disease susceptibility, and as a marker of Hib transmission before routine immunization was introduced in Kathmandu, 71 participants aged 7 months-77 years were recruited and 15 cord blood samples were collected for analysis of anti-polyribosylribitol phosphate antibody levels by enzyme-linked immunosorbent assay. Only 20% of children under 5 years old had levels considered protective (>0.15 µg/ml), rising to 83% of 15-54 year-olds. Prior to introduction of Hib vaccine in Kathmandu, the majority of young children were susceptible to disease