The threshold for the stimulation of breathing at altitude: physiological support for the aviation industry standard for aircraft pressurization

As aircraft ascend, cabin pressure is always maintained below an equivalent altitude of 8,000ft (~120mmHg O2, ~15.4% O2). The choice of 8,000ft is a compromise between engineering, fuel efficiency, cost, human comfort and human physiology (Aerospace Medical Association, 2008). The brain’s response to hypoxia is to stimulate breathing to counteract its effects. Currently, the threshold at which breathing is stimulated by hypoxia is inconsistent with cabin pressure regulations, being reported in 1947 by Dripps and Comroe, to be at a far higher altitude, at ~85mmHg O2 (~10% O2) (~17,500ft). This research team is unaware of any study, since 1947, that has tried to identify the ventilatory threshold to hypoxia. Using modern experimental methodology and statistical design this study reassesses the breathing threshold to hypoxia in 20 participants. This research indicates that breathing is more sensitive than previously demonstrated, with significant stimulation of breathing (by 1 L.min-1 ), combined with a significant lower PetCO2 (by 1 mmHg), being detectable at 15.2% oxygen (~121mmHg O2, ~7900ft)

Dynamic performance modelling of tidal stream turbines in ocean waves.

The primary aim of this work is to develop a tool to predict the lifetime performance of a tidal stream turbine. This involves the experimental validation of Blade Element Momentum Theory (BEMT) and implementation of an extended model to optimise blade design and predict performance over the operating range. Time varying non-linear upstream flows, such as wave action and velocity gradients are considered and the model is extended into the time domain to obtain the dynamic response of the rotor. In addition, to rationalise the environmental conditions that a device will encounter in its lifetime, representative sea-states and occurrences must be defined. A 1m diameter turbine is tow tested in the River Tawe. It is monitored and controlled such that the performance can be analysed over the operating range. An automated electrical control system is also tested. The results are compared to BEMT. The BEMT is numerically implemented and examined to determine its limitations. Off-optimum performance is considered. The model is extended to incorporate a time dependent flow field with additional velocity and acceleration terms to allow the consideration of wave kinematics. Resultant forces are defined and calculated for particular environmental conditions. Finally the results are interpreted to allow the estimation of lifetime loadings including peak loads and fatigue. The model is validated and a good correlation is found relative to standard BEMT. It is concluded that both a velocity gradient and a wave action may significantly reduce power output whilst increasing the loads on a system. It is also concluded that a 3 bladed rotor encounters far lower loadings than a 2 bladed equivalent over the device lifetime. It is also the intention of this study to compare and contrast various tidal stream turbine support structure concepts in terms of the suitability of each to withstand the lifetime loadings at reasonable cost. A number of support structure concepts are investigated from an impartial perspective. In conclusion there is not one concept which clearly surpasses the others in all areas

Summer thermal comfort and self-shading geometries in Passivhaus dwellings: A pilot study using future UK climates

© 2015 by the authors. This study uses numerical thermal simulation to investigate the potential use of building geometry to eliminate or reduce current and future thermal discomfort overheating risk in UK Passivhaus dwellings. The study focused on the optimum inclination of a south façade to make use of the building shape to self-protect itself. Dynamic simulation modelling software was used to test a range of different inclined façades with regards to their effectiveness in reducing overheating risk. The research found that implementing a tilted façade could completely eliminate the risk of overheating for current UK climates, but with some consequences for natural ventilation and daylighting. Future overheating was significantly reduced by the tilted façade. However, geometric considerations could not eradicate completely the risk of thermal discomfort overheating, particularly by the 2080s

Global congruence of carbon storage and biodiversity in terrestrial ecosystems

Deforestation is a main driver of climate change and biodiversity loss. An incentive mechanism to reduce emissions from deforestation and forest degradation (REDD) is being negotiated under the United Nations Framework Convention on Climate Change. Here we use the best available global data sets on terrestrial biodiversity and carbon storage to map and investigate potential synergies between carbon and biodiversity-oriented conservation. A strong association (rS= 0.82) between carbon stocks and species richness suggests that such synergies would be high, but unevenly distributed. Many areas of high value for biodiversity could be protected by carbon-based conservation, while others could benefit from complementary funding arising from their carbon content. Some high-biodiversity regions, however, would not benefit from carbon-focused conservation, and could become under increased pressure if REDD is implemented. Our results suggest that additional gains for biodiversity conservation are possible, without compromising the effectiveness for climate change mitigation, if REDD takes biodiversity distribution into account

Brilliance of a fire: innocence, experience and the theory of childhood

This essay offers an extensive rehabilitation and reappraisal of the concept of childhood innocence as a means of testing the boundaries of some prevailing constructions of childhood. It excavates in detail some of the lost histories of innocence in order to show that these are more diverse and more complex than established and pejorative assessments of them conventionally suggest. Recovering, in particular, the forgotten pedigree of the Romantic account of the innocence of childhood underlines its depth and furnishes an enriched understanding of its critical role in the coming of mass education - both as a catalyst of social change and as an alternative measure of the child-centeredness of the institutions of public education. Now largely and residually confined to the inheritance of nursery education, the concept of childhood innocence, and the wider Romantic project of which it is an element, can help question the assumptions underpinning modern, competence-centred philosophies of childhood

UWE Celebrating Bristol Green Capital 2015 - Activities portfolio (supporting document for UWE Celebrating Bristol Green Capital 2015 activities catalogue)

This Activities Portfolio details projects, events and initiatives which represent the work of hundreds of UWE staff and students during Bristol's year as European Green Capital in 2015. It is the working file to accompany the UWE Green Capital 2015 Activities Catalogue

Influence of muscle mass in the assessment of lower limb strength in COPD: validation of the prediction equation

Absence of established reference values limits application of quadriceps maximal voluntary contraction (QMVC) measurement. The impact of muscle mass inclusion in predictions is unclear. Prediction equations encompassing gender, age and size with (FFM+) and without (FFM−), derived in healthy adults (n=175), are presented and compared in two COPD cohorts recruited from primary care (COPD-PC, n=112) and a complex care COPD clinic (COPD-CC, n=189). Explained variance was comparable between the prediction models (R2: FFM+: 0.59, FFM−: 0.60) as were per cent predictions in COPD-PC (88.8%, 88.3%). However, fat-free mass inclusion reduced the prevalence of weakness in COPD, particularly in COPD-CC where 11.9% fewer were deemed weak

The influence of muscle mass in the assessment of lower limb strength in COPD [Abstract]

The influence of muscle mass in the assessment of lower limb strength in COPD [Abstract

Biodiversity and resilience of ecosystem functions

Accelerating rates of environmental change and the continued loss of global biodiversity threaten functions and services delivered by ecosystems. Much ecosystem monitoring and management is focused on the provision of ecosystem functions and services under current environmental conditions, yet this could lead to inappropriate management guidance and undervaluation of the importance of biodiversity. The maintenance of ecosystem functions and services under substantial predicted future environmental change (i.e., their ‘resilience’) is crucial. Here we identify a range of mechanisms underpinning the resilience of ecosystem functions across three ecological scales. Although potentially less important in the short term, biodiversity, encompassing variation from within species to across landscapes, may be crucial for the longer-term resilience of ecosystem functions and the services that they underpin