1,721,230 research outputs found
Dataset supporting the University of Southampton Doctoral Thesis: 'the ecological effects of physical habitat restoration in English chalk streams' by Lewis Adam Dolman
No full textDataset supporting the University of Southampton Doctoral Thesis: 'The ecological effects of physical habitat restoration in English chalk streams' by Lewis Adam Dolman.
This dataset contains data (excel files) for:
CHAPTER 5 - 'Quantifying the environmental impacts of low-head weirs and their removal in low power chalk streams'. This includes physical habitat and ecological monitoring data collected at a case study weir removal on the River Test (Hampshire, UK) and data collated from the Environment Agency's 'Fish and Ecology Data Explorer'.
CHAPTER 6 - 'Chalk stream restoration - physical and ecological responses to gravel augmentation'. This includes physical habitat and ecological monitoring data collected at two case study gravel augmentation restoration sites on the River Test and Itchen (Hampshire, UK).
CHAPTER 7 - 'Restoration over time - the physical and ecological responses to restoration in an English chalk stream'. This includes physical habitat and ecological monitoring data collected at two case study instream physical habitat restoration sites on the River Test (Hampshire, UK). Additionally, control macroinvertebrate datasets collated from the Environment Agency 'Fish and Ecology Data Explorer' and 'SmartRivers' dataset.
CHAPTER 8 - 'Non-invasive population estimates of freshwater fishes using remote underwater video'. This includes data from an experiment aiming to understand whether it is possible to identify individual fish from unique identifiable features (e.g. spots, stripes) and morphometrics (i.e. body measurements) from photographs and underwater video. This is followed by an experiment exploring the accuracy of non-invasive population estimates created using mark-recapture estimates from underwater video and unique identifiable features.
For further details on this dataset, see the 'README' file.
This PhD was funded by the Engineering and Physical Sciences Research Council (EP/L01582X/1) and Environment Agency.
Data Licence: CC BY</span
An investigation into separation enhancement methods for miniaturised planar capillary electrophoresis devices
No full textThe analytical capability of field-portable instruments and in-situ devices is often limited due to cost, complexity and spatial restrictions. With powerful analytical methods incorporated onto miniaturised sensor platforms, in-depth sample and environmental examinations become feasible. There has been significant research reported in the literature for improving miniaturised capillary electrophoresis systems alongside lab-on-a-chip applications. The work presented in this thesis discusses the development of novel methods to improve the separation resolution of capillary electrophoresis on microfluidic devices without compromising device size. Further to this, complex chemical buffering systems have been avoided since they tend to make the end device highly application specific.The separation resolution of capillary electrophoresis can be enhanced by dynamic control of the electroosmotic flow. This is achieved through control of the zeta-potential, which can be modified by applying a potential to an electrode close to the surface of the separation channel. The separation enhancement methods increase the effective channel length and therefore can be used to aid the incorporation of capillary electrophoresis into both portable field instruments and for in-situ systems.Computational models have been developed for an in-depth investigation into the proposed separation enhancement routines. Where possible, these models have been experimentally verified. The operation limits of the enhancement methods have been investigated, and related to the composition of the sample to infer design criteria
Functionalisation of optical fibres by the integration of 2D transition metal dichalcogenide materials
No full textIn this thesis, the concept of functionalising microstructured optical fibres is proposed using a unique and novel concept of liquid phase deposition of two dimensional materials. Two fields of research have been analysed in this work. Firstly, the concept of thermal poling – whereby centrosymmetric materials with negligible values of second order nonlinearity are heated under the presence of an electrical field to break the centrosymmetry of the structure and generate a non-zero second order nonlinearity (SON) – is analysed. This quadratic nonlinearity can potentially be augmented via the insertion of intrinsically highly nonlinear 2D materials such as Transition Metal Dichalcogenides. Another area of research has been functionalising the hollow regions of antiresonant optical fibres. This is a relatively new design of fibre, whereby light is guided in a hollow core using a guidance mechanism known as inhibited coupling. The hollow regions of an anti-resonant fibre (ARF) offer an excellent template for the deposition of functional materials such as 2D films. When the optical properties of such materials can be modified via external stimuli, it offers a method to modify the transmission capability of the optical fibre. We successfully demonstrate electro-optical control on the devices, showing loss of 3dB in the guidance regions. Following on from these results, other materials were also investigated for their electro-optic properties including ZnSe in its bulk form and compared with the performance of the 2D materials
The ecological effects of physical habitat restoration in English chalk streams
No full textChalk streams are globally rare and unique systems that have been extensively subjected to physical modification. This has contributed to the widespread degradation of ecological communities in chalk streams and failures to adhere to legislation (e.g. Water Framework Directive). Physical restoration has emerged as a key strategy to improve the condition of chalk streams, but a current lack of evidence for its effectiveness constrains the development of sound practice. This thesis aimed to develop understanding of the effects of restoration on physical habitat and ecology in English chalk streams. A series of case study appraisals were undertaken to understand: (1) the physical and ecological effects of different techniques (i.e. weir removal and gravel augmentation); (2) the influence of time since restoration; (3) the effects of restoration on different ecological groups. Additionally, (4) a methodological approach for non-invasively evaluating fish populations was developed to help improve monitoring capabilities in chalk streams. Weir removal rapidly altered habitat and ecological communities, especially directly upstream which became more lotic. Little evidence of sediment-pulse related impacts downstream of the weir was found, possibly due to additional silt-management methods which facilitated recovery. Gravel augmentation desirably altered habitat and ecology over the timescale studied (e.g. enhanced macroinvertebrate diversity). However, variability between sites, time periods and ecological groups signifies widespread uncertainties in restoration outcomes and the need to develop a better understanding of the drivers behind these. Time was a key factor influencing the observed effects of restoration (e.g. due to lag-effects). Furthermore, responses varied considerably between ecological groups, where changes in macroinvertebrates (e.g. increased diversity) and fish (e.g. increased brown trout sightings) were not reciprocated in macrophytes. These findings highlight the need for appraisals to take place at commensurate temporal scales and ideally using a multi-taxa approach to understand responses more accurately. Remote underwater video proved a useful tool for assessing fish communities and population size. Given the adaptability and utility of the technique, as well as its potential application as a citizen science methodology, it may prove useful for monitoring at chalk stream restoration projects and requires further investigation. Overall, this thesis contributes valuable evidence suggesting restoration can be an effective tool for desirably altering habitat and ecological communities in chalk streams. However, the need to conduct more robust appraisals to consolidate knowledge is highlighted and emphasises the need to fund the development of flagship case studies to guide and inspire future restoration efforts. <br/
Changing practice by changing pressures: a role for oscillating positive expiratory pressure in chronic obstructive pulmonary disease
No full textModelling new techniques for improving separation in miniature capillary- and planar-based capillary electrophoresis systems
No full textThe capillary/channel length is an important factor in capillary electrophoresis (CE) systems since it is directly related to the amount of separation attainable. In this work we present methods to increase the effective channel length without the need to modify the physical channel length. Using an electrode located close to the capillary surface it is possible to dynamically modify zeta-potential and therefore the electroosmotic flow (EOF). By controlling the EOF, certain ionic species within a sample can be held in a short channel whilst other species migrate along the channel. Alternatively the sample can be transported back and forth along the active channel length until sufficient separation has been attained. CE enables detailed analysis of a sample’s composition and this is of interest to a range of applications
Singing for Lung Health: evaluation of the British Lung Foundation programme
No full textIntroduction: Singing for Lung Health (SLH) is a novel intervention for people with respiratory disease, including physical and vocal warm ups, rhythm and pitch games, repertoire and cool down/relaxation exercises. Groups are run by leaders who have received quality assured British Lung Foundation (BLF) training (Lewis A. et al, bmjresp 2017; 000216). Qualitative results suggest benefits to physical, mental and emotional health. Limited data also suggest objective improvements in measures of quality of life with SLH are achievable (Lewis A. et al, npjpcrm 2016;80). It is not known how effective the SLH groups supported by the BLF in the UK are.Aims and objectives: to understand the clinical impact SLH has on people with respiratory disease.Methods: the BLF conducted a questionnaire survey of 228 singers with respiratory disease from its SLH groups in 2016-2017. Questionnaires were administered prior to participants’ first session and after 12 weeks of singing.Results: 113 (49.5%) of participants provided 12 week data. There were significant improvements in CAT score (Mean -1.4 CI: (0.25 - -2.48) (p = 0.017). Furthermore, 45% of singers reported reduced GP visits (p = 0.00002) and 18% reported reduced hospital admissions (p = 0.01). However, there were no significant improvements in general quality of life, anxiety, patient activation, breathlessness or inhaler use.Conclusion: this evaluation found that participants in SLH groups report improvement in respiratory health-related quality of life and a reduction in healthcare utilisation. SLH has potential economic and health benefits. Therefore, to confirm these findings these endpoints should be evaluated further in large scale randomised controlled trials
Evolution of voltage transients during the switching of a MEMS relay with Au/MWCNT contacts
No full textGold is commonly used for microelectromechanical electrical contacts due to its desirable electrical and mechanical properties; however, the lifetime of gold contacts is limited, particularly in the case of hot switching. To improve the lifetime of electrical contacts, we have developed a gold-coated multiwalled carbon nanotube bilayer composite. Experiments with these composites have shown that the switching dynamics vary over the lifetime of the switch. The change in potential across the switch contacts during the contact-break process, referred to as the transient opening voltage, has been monitored at a number of intervals throughout the switch life. The transient opening voltage shows behavior indicative of the molten metal bridge (MMB) phenomenon. While stable for most of the contact lifetime, the duration of this behavior increases sharply as the contacts approach failure. Throughout the switch lifetime, the contacts are required to survive a large number of opening and closing cycles and, therefore, it is important to understand the switching dynamics. A contact pair was investigated to failure where the experimental conditions were: load current and voltage of 50 mA and 4 V, respectively. Failure occurred after 28 million hot-switched cycles. The average energy of the MMB process was evaluated as 1.54 \mu text{J} per opening event during the stable region, this rose to 13.2 \mu text{J} shortly before failure. An experiment run under similar conditions but with a lower load current of 10 mA, which was switched for over 500 million cycles, showed a stable contact resistance and an average MMB energy of 5~\Omega and 57 nJ, respectively
Qualitative study of patients experiences and perceptions of stepping down asthma medication in primary care across England
No full textBackground: guidelines recommend that asthma medication should be stepped down to the minimally effective dose that achieves symptom control. Stepping down aims to prevent adverse medication effects and unnecessary costs but is often not implemented in primary care, where most asthma patients are managed. Little is known about the experiences and views of patients regarding stepping down. Methods: stable asthma patients, with regular use of a preventer inhaler, from GP practices across England, participated in a survey and/or semi-structured interview. Questions explored the patient’s understanding of their asthma, views and knowledge of preventer inhalers, experiences and perceptions of stepping down asthma medication. Qualitative group-based multi-disciplinary thematic analysis by two healthcare professionals and a patient were performed.Results: 143 patients responded to the survey, 63% were female, between the ages 18-80 years, and including geographical areas across the UK, 17 of whom participated in an interview. Half of these stable asthma patients, most with asthma for more than 10 years, had never had a discussion regarding stepping down asthma medication. Most stepping down that had occurred was related to seasonal changes in asthma control. Four overarching themes from the interviews were identified, (i) experiences of living with asthma and needing inhalers, (ii) insufficient education regarding preventer inhalers, (ii) stepping down is agreeable and possible and (iv) current asthma care is suboptimal.Conclusion: stable asthma patients were able to self-manage their asthma well. They had little awareness of medication adverse effects and minimal experience of having their medication stepped down by a healthcare professional. Most were inclined to step down, if clinically safe to do so, indeed some had reduced their medication doses themselves, without professional guidance.<br/
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