Separating a wavefield by propagation direction

Determining the propagation direction of waves in a wavefield is important in several seismic imaging techniques and applications. This can be achieved using the Poynting vector method, but it performs poorly when waves overlap, returning incorrect wave amplitude and direction. An alternative, the local slowness method, is capable of separating overlapping waves, but suffers from low angular resolution. We describe modifications of these two approaches that improve the ability to extract the wave amplitude propagating in different directions. The primary modification is the addition of a wavefront orientation separation step. We evaluate the original and modified methods' ability to separate six overlapping waves in a constant velocity model and find that the modifications significantly improve the results

A multi-pass one way method to include turning waves and multiples

Conventional one way migration methods exclude turning waves and multiples. We propose an algorithm that uses multiple passes to extend the one way method to efficiently include these wavepaths. A comparison of the images produced by the regular one way algorithm, RTM, and the new method, shows that this new method can significantly improve the image in regions of interest, and in certain situations may even provide more useful information than RTM. The runtime is demonstrated to be in between that of regular one way and RTM, while the physical memory required is considerably lower than that of RTM

Reverse Time Migration in the presence of known sharp interfaces

We propose using the forward propagated source wave to create synthetic receiver data on the surfaces of the computational domain where real receiver data is not available as a means of exploiting known information about reflector locations in Reverse Time Migration. The inclusion of synthetic boundary data can make true amplitude imaging possible, and reduce the artifacts associated with the inclusion of multiples. Here, we describe the new method, present synthetic examples, and propose an appropriate imaging condition

Feedback on Academic Essay Writing through pre-Emptive Hints: Moving Towards "Advice for Action"

This paper adopts an “advice for action” approach to feedback in educational practice: addressing how provision of “hints” to participants before they write academic essays can support their understanding and performance in essay-writing tasks. We explored differences in performance by type of hint, and whether there was a transfer of better performance in subsequent essays. Fifty participants were recruited, consisting of eight men and 42 women aged 18-80. Participants were assigned in rotation to four groups, and asked to write two essays. Groups 1 and 3 received hints before Essay 1, whilst Groups 2 and 4 received hints before Essay 2. Groups 1 and 2 received essential hints; Groups 3 and 4 received helpful hints. Essays were marked against set criteria. The results showed that an “advice for action” approach to essay-writing, in the form of hints, can significantly improve writers’ marks. Specifically higher marks were gained for the introduction, conclusion and use of evidence: critical components of “good” academic essays. As the hints given were content-free, this approach has the potential to instantly benefit tutors and students across subject domains and institutions and is informing the development of a technical system that can offer formative feedback as students draft essays

How leaders generate hope in their followers

The purpose of this research was to understand how leaders in organisations generate hope in their followers. High hope leaders who generate hope in their followers may be described as leaders who have a positive and engaging management style, and who positively influence the people around them by generating hope. There is significant evidence that a large part of a leader’s role is to inspire hope in followers, and that high hope managers are more effective and successful than leaders who lack hope. Leaders who inspire hope in followers were identified, and nine qualitative semistructured depth interviews were conducted with the followers of these leaders. What emerged was a checklist of behaviours, actions and attitudes of high-hope leaders, which may in future serve as a guide for other leaders who seek to increase their positive influence on followers, and consequently, their positive impact on organisations and the economy. Nine common behaviours which were key in generating hope in followers emerged from this research, these are: 1. Each of the leaders has a high level of personal competence and credibility – they are personally very smart and very successful 2. They trust their people implicitly, and don’t micromanage followers 3. They empower their people 4. They are keen developers of people 5. Access to the leader is relatively easy – they are available to their people 6. They believe in and believe the best about their people 7. They are great communicators, and willingly share knowledge and information with their followers 8. They relentlessly drive high performance 9. They inspire their followers to work hard, and contribute large amounts of discretionary effortDissertation (MBA)--University of Pretoria, 2009.Gordon Institute of Business Science (GIBS)unrestricte

Minimising diagnostic uncertainties in early pregnancy

Introduction Approximately one in five women experience abdominal pain and/or vaginal bleeding in early pregnancy. This usually prompts referral to an Early Pregnancy Assessment Unit where an ultrasound scan will be performed. Following the ultrasound, either a certain or uncertain diagnosis will be made. Certain diagnoses may be positive, i.e. a viable intrauterine pregnancy, or negative, i.e. a non-viable or ectopic pregnancy. Uncertain diagnoses occur when there is ambiguity regarding either the location or the viability of the pregnancy. Up to 25% of women attending an Early Pregnancy Assessment Unit are given such a diagnosis at their initial visit. All women with a diagnosis of either a pregnancy of unknown location or uncertain viability need to be followed-up until a definitive diagnosis can be made. At present this is haphazard and protracted, commonly taking up to two weeks to resolve and requiring multiple visits for various different investigations. This takes a considerable amount of time and costs a not insignificant amount of money. Furthermore, in the time taken to make a definitive diagnosis, a stable woman with an unknown miscarriage or ectopic pregnancy may become unstable and require immediate resuscitation, life-saving blood transfusion and/or emergency surgery. Aims The aim of this PhD was to develop methods to minimise the number of women given uncertain diagnoses in early pregnancy, or to at least minimise the duration of uncertainty if the diagnosis is unavoidable. Several different studies were undertaken in an attempt to accomplish this. Studies We initially undertook a prospective cohort study to determine the levels of anxiety generated by uncertain diagnoses in early pregnancy was undertaken. Women with uncertain diagnoses were found to be significantly more anxious (as measured using the standardized short form of Spielberger’s state-trait anxiety inventory) than their counterparts given certain diagnoses (23±0.79 versus 14±6.6), even if these certain diagnoses were not associated with an ongoing pregnancy. This study served to further justify the main objective. We then performed a systematic review and meta-analysis to identify and determine the diagnostic accuracy of various different ultrasonographic features to predict (a) an intrauterine pregnancy prior to visualization of embryonic contents and (b) a tubal ectopic pregnancy in the absence of an obvious extra-uterine embryo. This study identified the double decidual sac sign as a potential marker to be able to accurately differentiate a true gestation sac from a pseudosac with a sensitivity of 82% (95% CI, 68-90%), specificity of 97% (95% Ci, 76-100%), positive likelihood ratio of 30 (95% CI, 2.8-331) and negative likelihood ratio of 0.19 (95% CI, 0.10-0.35). The quality of the studies included in the meta-analysis however precluded the use of the double decidual sac sign in clinical practice without further validation As a consequence, we carried out a prospective study following STARD guidelines to determine the diagnostic accuracy of the double decidual sac sign to predict an intrauterine pregnancy prior to visualization of embryonic contents using modern, high-resolution transvaginal ultrasound. This study found that the double decidual sac sign predicted an intrauterine pregnancy with a sensitivity of 94% (95% Ci, 85-98%), specificity of 100% (95% CI, 16-100%) and overall diagnostic accuracy of 94% (95% CI, 88-100%). The positive and negative predictive values are 100% (95% CI, 94-100%) and 33% (95% CI, 4.3-78%) respectively whilst the positive likelihood ratio was infinite and the negative likelihood ratio was 0.06 (95% CI, 0.02-0.16). These results suggest that the meta-analysis under-estimated the ability of the double decidual sac sign to differentiate between a true gestation sac and a pseudosac. Subsequently, we conducted a study incorporating off-line analysis of ultrasonographic images to determine the inter- and intra-observer reliability of the double decidual sac sign to predict an intrauterine pregnancy prior to ultrasonographic visualization of embryonic contents. This involved fifteen observers from around the United Kingdom remotely assessing a selection of two-dimensional images from 25 of the diagnostic accuracy study participants. There was significant (p<0.01) agreement amongst the observers but the level of agreement was only ‘fair’, reflected by kappa statistics of 0.25, 0.33 and 0.21. Following a period of focused training, the inter-observer reliability significantly increased demonstrated by kappa statistics of 0.70, 0.63 and 0.53. The intra-observer reliability ranged from ‘substantial’ (K=0.65) to ‘almost perfect’ (K=0.92). These results demonstrate that the double decidual sac sign has the potential, after training, to be both reliable and precise, making it a very useful ultrasonographic sign in clinical practice. Finally, we undertook a prognostic research study, following REMARK recommendations, investigating the ability of five serum biomarkers to predict pregnancy outcome in women with pregnancies of uncertain viability. Candidate biomarkers included Angiopoietin-1 (Ang-1), Angiopoietin-2 (Ang-2), soluble FMS-like Tyrosine Kinase-1 (Flt-1), serum TNF-Related Apoptosis Inducing Ligand and Interleukin-15. Serum concentrations of Ang-2 and Flt-1 were significantly lower in pregnancies of uncertain viability that were subsequently proven to be viable than those that were subsequently proven to be non-viable (Ang-2 1510pg/ml versus 2365pg/ml and Flt-1 103pg/ml versus 202pg/ml). Furthermore, there were statistically significant (p<0.01), linear (p-value for trend <0.01) associations between Ang-2 and Flt-1 concentrations and subsequent pregnancy viability such that women with a pregnancy of uncertain viability and Ang-2 concentrations greater than or equal to 2666pg/ml were 64% less likely to have a viable pregnancy than those with Ang-2 concentrations less than or equal to 1382pg/ml and women with a pregnancy of uncertain viability and Flt-1 concentrations greater than or equal to 142pg/ml were 50% less likely to have a viable pregnancy than those with Flt-1 concentrations less than or equal to 87pg/ml. These findings suggest that Ang-2 and Flt-1 may be useful in the prediction of pregnancy viability in cases of uncertainty. Discussion One of the biggest challenges in early pregnancy ultrasonography is accurate differentiation between a true gestation sac and a pseudosac. Pseudosacs, although rare, are strongly suggestive of an ectopic pregnancy, hence it is an important distinction to make, ideally as soon as possible. Both appear initially as intrauterine fluid collections or ‘empty sacs’. Whilst experts may claim that it is not difficult to differentiate between the two structures, in clinical practice, many of the individuals undertaking the scans in early pregnancy do not claim to be experts. Traditional teaching has always been to wait until either a yolk sac or fetal pole are visualized within the sac before confirming a definite intrauterine pregnancy. Although safe, inherent with this approach is that an intrauterine fluid collection is visible using transvaginal ultrasound from around day 28 but a yolk sac is not visible until at least day 35. If an ultrasound is undertaken during this time, an ‘empty sac’ will be seen and uncertainty will ensue. Application of the results from the studies described above could potentially revolutionize the care of women with diagnostic uncertainties in early pregnancy. Firstly, the confirmation that uncertain diagnoses in early pregnancy are highly anxiogenic, means that Early Pregnancy Assessment Units can now justify the allocation of resources to help alleviate this distress. This is crucial if we are to improve the holistic nature of the care provided to women with complications of early pregnancy. Furthermore, the discovery that the double decidual sac sign can accurately predict an intrauterine pregnancy prior to visualization of embryonic contents (and therefore effectively exclude an ectopic pregnancy) means that we can rationalise follow-up, improve consistency and minimise error in the management of women with ultrasonographic evidence of an empty sac in early pregnancy. Although it could be argued that utilization of the double decidual sac sign does not minimise the number of women given uncertain diagnoses in early pregnancy, merely swap concerns regarding location to ones regarding viability, in clinical practice it is the potential consequences of pregnancies of unknown location that are most hazardous, both because of the immediate threat to health and the future threats to fertility. Furthermore, if the findings from our prognosis study are confirmed, and appropriate threshold levels for our biomarkers determined, it may be possible to minimise the duration of uncertainty for women with pregnancies of uncertain viability to hours rather than weeks. Using a combination of approaches therefore, we have achieved the overall aim of this thesis in minimising diagnostic uncertainties in early pregnancy, the clinical benefits of which are multifold. Not only does it reduce anxiety for women, but also prevents unnecessary investigations from being performed in those with an intrauterine pregnancy and minimise morbidity and mortality, permit earlier, potentially less invasive intervention and possibly preserve future fertility for women with an ectopic pregnancy

The relationship between nature connectedness and eudaimonic well-being: A meta-analysis

Nature connectedness relates to an individual’s subjective sense of their relationship with the natural world. A recent meta-analysis has found that people who are more connected to nature also tend to have higher levels of self-reported hedonic well-being; however, no reviews have focussed on nature connection and eudaimonic well-being. This meta-analysis was undertaken to explore the relationship of nature connection with eudaimonic well-being and to test the hypothesis that this relationship is stronger than that of nature connection and hedonic well-being. From 20 samples (n = 4758), a small significant effect size was found for the relationship of nature connection and eudaimonic well-being (r = 0.24); there was no significant difference between this and the effect size (from 30 samples n = 11638) for hedonic well-being (r = 0.20). Of the eudaimonic well-being subscales, personal growth had a moderate effect size which was significantly larger than the effect sizes for autonomy, purpose in life/meaning, self-acceptance, positive relations with others and environmental mastery, but not vitality. Thus, individuals who are more connected to nature tend to have greater eudaimonic well-being, and in particular have higher levels of self-reported personal growth.University of Derb

Developing the Role of the Clinical Academic Nurse, Midwife and Allied Health Professional in Healthcare Organisations

Clinical academics provide key contributions to positive outcomes in the delivery of high-quality health and social care; however, building capacity and capability for these roles for Nurses, Midwives and Allied Health Professionals (NMAHPs) within contemporary healthcare settings is often complex and challenging. Accessing funding and training, such as that provided by the National Institute for Health Research (NIHR), can remain beyond the reach of NMAHPs at point-of-care delivery because of limited structural empowerment, practical support and a culture inhibiting the growth of clinical academic careers. This article will discuss strategic developments and partnerships from two organisations, both with a positive track record of supporting clinical academic career development for NMAHPs. We aim to provide practical and applicable examples showing how NMAHPs have been supported from foundational to post-doctoral level and outline these under three key headings: strategic commitment; structures to engage, enthuse and empower clinical academic careers; and realising the benefits for staff and patient experience. We contend that a wide-ranging level of support is required to encourage aspiring clinical academics to navigate this complex journey, often where the development of personal confidence, and access to early career models combining clinical and research activity are pivotal. We conclude that when crafted and created effectively with sustainable commitment by organisations, NMAHP clinical academics provide an innovative workforce solution with the knowledge and skills essential for a contemporary NHS healthcare system