On classifying proper knots in open 3-manifolds

AbstractWe examine proper embeddings of the real line into open 3-manifolds and their proper isotopy classes, i.e., proper knots and their equivalence classes. In particular, for proper knots running between distinct ends of an open 3-manifold M, we give conditions on the structure of the ends of M under which proper homotopy implies proper isotopy. To prove this result, geometric techniques are employed which enable one to properly isotope a proper knot that is wild in the neighbourhood of an end to one that is tame

Crystal Structures, Properties and Reactivity of Selected Macrocyclic and Chelate Complexes of Ni(II)

In this dissertation we describe the structure, properties and decomposition reactions of a series of Ni(II) coordination complexes formed from reaction of the appropriate macrocyclic or chelating ligand with a simple nickel salt. The ligands used were 12aneS4 (1,4,7,10-tetrathiacyclododecane), 14aneS4 (1,4,8,11-tetrathiacyclotetradecane), cyclam (1,4,8,11-tetraazacyclotetradecane), dppe (1,2- (diphenylphosphino)ethane), and PP3 (tris-(2-(diphenylphosphino)ethyl)phosphine). The work falls into three broad sections related to, respectively: catalysis of the reversible decomposition of complex hydrides for hydrogen storage; the unusual structure of [Ni(H2O)6][Ni(cyclam)(SO4)2]; and the facile reversible hydration of Ni(12aneS4)(BF4)2. The ability of transition metal salts, particularly those of titanium, to catalyse the dehydrogenation/rehydrogenation of complex hydride hydrogen stores such as NaAlH4 is well known. Unfortunately the activity of these simple salts is not sufficient for commercial use in light vehicles, and further improvements to the catalysts are hampered both by the limited scope for adjusting the catalyst, and the lack of detailed knowledge of the active species. Instead of using such simple salts, we have investigated complexes of Ni(II) and 12aneS4, 14aneS4, cyclam, dppe and PP3. This approach was taken to serve two objectives: the first that should catalytic activity be found, we should have a good idea of the active species and thus be better able to improve upon it; and second, that such complexes often form molecular crystals which should be significantly easier to disperse in the hydrogen store by high-energy milling than the ionic crystals of the simple salts. The stability of the complexes was tested with a series of lithium and sodium borohydride and alanate compounds with progressively more aggressive reducing properties. The tetrathioether complexes were not resistant to reduction, even by dilute NaBH4 solution, forming black/brown tars or solids with poorly defined infrared spectra and showing no peaks in their XRD patterns. The cyclam complexes (Ni(cyclam)SO4, Ni(cyclam)(ClO4)2 or Ni(cyclam)(BF4)2), however, could be reacted with either NaBH4 or LiBH4 to form a nickel borohydride complex, Ni(cyclam)(BH4)2, of unusual stability. Both cis and trans isomers of this distorted octahedral complex were obtained, and their crystal structures investigated in some detail, including by powder neutron diffraction. The potential of Ni(cyclam)(BH4)2 for catalysis in complex hydride hydrogen stores was assessed by simultaneous thermogravimetric analysis and differential scanning calorimetry (TGA/DSC) and the gases evolved analysed in real-time by infrared spectroscopy and/or mass spectrometry. A difference in the decomposition profile of the two isomers (with the cis configuration decomposing at lower temperature than the trans) demonstrated the importance of the geometry of such complexes when iii considering them for such uses. However, the complexes did not show any catalytic behaviour toward the decomposition of either lithium or sodium borohydride when milled with them in a high- energy disc mill. Furthermore, both isomers of Ni(cyclam)(BH4)2 decomposed exothermically, ruling them out for use as catalysts in onboard reversible stores, for which an endothermic decomposition is required. The bidentate phosphine chelate dppe showed behaviour similar to that of the thioether macrocycles, i.e., it did not prevent reduction of Ni(II) even by dilute solutions of NaBH4. In contrast, the tetradentate PP3 ligand was able to prevent reduction even by the highly aggressive reducing agent LiAlH4, forming a penta-coordinated Ni(II) hydride complex. The formation of this hydride complex could also be performed in the solid state by high energy disc-milling Ni(PP3)(BF4)2 with one of the complex hydrides studied. Analysis of the decomposition of the PP3 complex by TGA/DSC, showed that as with Ni(cyclam)(BH4)2, they do not provide any catalytic behaviour when milled with complex hydrides, and that both the precursor (Ni(PP3)(BF4)2) and hydride complexes decompose exothermically, making them unsuitable as catalysts in onboard reversible stores. From this series of experiments, we conclude that the stability of the Ni(II) complexes with respect to reduction by complex hydrides varies according to the donor type in the following series O, S < N < P. Though catalysis of the decomposition (hydrogen evolving) reaction of borohydrides and alanates was not observed with any of the complexes, further work may yet allow for the development of such catalysts. In particular, the use of mixed-donor chelates or macrocycles and/or bridged bi-metallic complexes, with each metal centre donating or accepting a single electron in the two-electron oxidation/reduction associated with H2 + 2e− ⇌ 2H−, perhaps being necessary. In our view, complexes involving P donors show the most promise for future research due to the stability of such complexes even in highly reducing environments. However, other restrictions inherent to the technology may yet prevent the use of complex hydrides as hydrogen storage materials for use in cars, particularly the significant problems associated with heat management upon onboard re- fueling, and these are also discussed. The unusual structure of [Ni(H2O)6][Ni(cyclam)(SO4)2], synthesised as a by-product of the standard Ni(cyclam)SO4 complex, is peculiar in having all the stronger σ-donors (cyclam and SO42−) attached to the same nickel centre. Only two other complexes in the Cambridge Structural Database bear a superficial similarity to this complex, and upon closer inspection even these are actually quite different. A substantial network of strong hydrogen bonds links the cationic and anionic complexes of [Ni(H2O)6][Ni(cyclam)(SO4)2] and is likely the source of the stability of this highly novel structure. iv Ni(12aneS4)(BF4)2 was found to absorb and desorb water very easily, with hydration of a powdered sample occurring in minutes (and surface effects clearly visible in seconds) by simple exposure to atmospheric air, and dehydration within seconds by heating to about 100 °C, in minutes by reducing the pressure to a few mbar, or over several hours in a dry atmosphere at room temperature and pressure. The structures of the complexes were solved from powder synchrotron X-ray diffraction patterns and found to have a clear topotactic relationship with highly anisotropic expansion of lattice parameters. Upon hydration, the flexibility of the 12aneS4 ring allows it to fold back and make room for the two water molecules that attach directly to the nickel to form [Ni(12aneS4)(H2O)2](BF4)2. The thermodynamic and kinetic aspects of the solid state reaction were investigated by TGA/DSC. With a very slow temperature ramp (as low as 0.02 K min−1) and no purging gas, this technique showed two separate processes occurring for both hydration and dehydration, attributed to the addition or loss of one equivalent of water at each step. The enthalpy, entropy and activation energy for each step in static air and for the overall reaction with purging gas were estimated using both the Kissinger and Ozawa-Flynn-Wall approaches. The calculated activation energy was found to be highly dependent on whether the sample chamber was purged during the experiment with dry Ar gas or not, which in removing water from the crystallite surfaces, points to the important role the reversibility of the reaction plays in the overall kinetics. The anhydrous complex, expected to have a low-spin d8 electronic configuration, shows ‘anomalous’ magnetic susceptibility, most likely due to its slight deviation away from square planar geometry and therefore imperfect quenching of the orbital angular momentum. The octahedral hydrated complex, however, shows magnetic behaviour typical of a high-spin d8 configuration

Evidence of raised levels of autistic traits in a homeless population.

This thesis focuses on the relationship between autism spectrum condition (ASC) and homelessness. Part 1 is a systematic review of whether and how ASC overlaps with the personality disorders (PDs) schizoid PD and schizotypal PD. There was little evidence for the nature of the overlap between schizoid PD and ASC, but some studies did suggest that having ASC may be a risk factor for the development of this PD. There was more evidence for the relationship between schizotypal PD and ASC, with studies showing that overlap was minimal, although differentiating the conditions could be challenging. The findings informed decision making in the empirical study reported in part 2 of the thesis. Part 2 is a study into whether rates of ASC were raised in a homeless population. As there was no previous peer-reviewed research in this area the study aimed to begin to develop an evidence base. It did this by identifying what proportion of the homeless population studied presented with the full range of traits associated with ASC, rather than by seeking to make confirmed diagnoses. It found that a relatively high proportion did show strong evidence of ASC traits, which suggests that rates of this condition may be raised in this population and that further investigation is required. This was part of a joint study (Ryder, 2017) with Morag Ryder, trainee clinical psychologist also at University College London (UCL). Part 3 is a critical appraisal of the systematic review and empirical study. It discusses the dilemmas inherent in carrying out research into homelessness, where data collection is difficult and there are many risks to validity, and argues that despite this it was important to carry out the empirical study. It also details measures taken to increase the impact of the research and reflections on how this was carried out

An analysis of the agricultural and industrial life of south east England with especial reference to the effect of the developing Kent coalfield thereon

Introduction. Chapter I Population Distribution and Changes illustrative of the major phases of the life of S.E. England. An analysis of the 1931 Census of the region and a comparison with the Censuses of 1911 and 1921. The growth of the population and the relative importance and major features of distribution of its industrial and agricultural elements. Chapter II The New Coalfield. Its location, physiography and geology. A short history of its discovery and development and a consideration of output and labour. A description of transport and markets and their geographic control. Chapter III Non-Agricultural Industry. The geographic and economic conditions governing the location and development of the major typical industries of S.E. England, A description of labour, transport and market conditions and a consideration of the Industries as consumers of Kent coal. The Paper Industry The Cement Industry The Brick and Tile Industry. Chapter IV Agricultural Industry. An analysis of the physiographic background of agriculture: climate, topography, soil and drainage. Some aspects of the economic background of agriculture - a broad consideration of markets; the distribution and type of farming population; the size and type of farms. Present agricultural production, distribution and marketing. A comparison with pre-war conditions. A correlation of agricultural conditions with the controlling factors of the physiographic and economic background and a consideration of subordinate agricultural industries in relation thereto. General Transport Considerations. Water Transport and Port Conditions. Inland Waterways Some aspects of geographic and economic conditions at the ports; their trade and development. Land Routes; their geographic control and present character. VI Regional Planning. Some consideration of the expected future development of the region from an examination of Regional Planning Reports. A summary of the industrial and agricultural life of the S.E. as reflected therein. <p

The prevalence of autistic traits in a homeless population

Anecdotal evidence suggests that autistic people experience an elevated risk of homelessness, but systematic empirical research on this topic is lacking. As a step towards filling this gap in knowledge, we conducted a preliminary investigation of the prevalence of Diagnostic and Statistical Manual of Mental Disorders (5th ed.) autism symptoms in a group of long-term homeless people. The entire caseload ( N = 106) of a UK homeless outreach team was screened (excluding individuals born outside of the United Kingdom or Republic of Ireland) using an in-depth, semi-structured interview with keyworkers, based on Diagnostic and Statistical Manual of Mental Disorders (5th ed.) diagnostic criteria. This showed adequate inter-rater reliability, as well as evidence of criterion and construct validity. Of the sample, 13 people (12.3%, 95% confidence interval (7.0, 20.4)) screened positive, meeting Diagnostic and Statistical Manual of Mental Disorders (5th ed.) autism criteria by keyworker report. A further nine people (8.5%, 95% confidence interval (4.5, 15.3)) were 'marginal', having autistic traits that were not quite sufficient to meet Diagnostic and Statistical Manual of Mental Disorders (5th ed.) criteria. Those with elevated autistic traits, compared to those without, tended to be more socially isolated and less likely to use substances. This study has provided initial evidence that autistic traits are over-represented among homeless people and that autistic homeless people may show a distinct pattern of characteristics and needs. Further investigation is required to build upon these provisional findings

Implementation of the Crisis Resolution Team model in adult mental health settings: a systematic review.

Crisis Resolution Teams (CRTs) aim to offer an alternative to hospital admission during mental health crises, providing rapid assessment, home treatment, and facilitation of early discharge from hospital. CRTs were implemented nationally in England following the NHS Plan of 2000. Single centre studies suggest CRTs can reduce hospital admissions and increase service users' satisfaction: however, there is also evidence that model implementation and outcomes vary considerably. Evidence on crucial characteristics of effective CRTs is needed to allow team functioning to be optimised. This review aims to establish what evidence, if any, is available regarding the characteristics of effective and acceptable CRTs

A Randomised Controlled Trial of a Brief Online Mindfulness-Based Intervention in a Non-clinical Population: Replication and Extension

Building on previous research, this study compared the effects of two brief, online mindfulness-based interventions (MBIs; with and without formal meditation practice) and a no intervention control group in a non-clinical sample. One hundred and fifty-five university staff and students were randomly allocated to a 2-week, self-guided, online MBI with or without mindfulness meditation practice, or a wait list control. Measures of mindfulness, perceived stress, perseverative thinking and anxiety/depression symptoms within were administered before and after the intervention period. Intention to treat analysis identified significant differences between groups on change over time for all measured outcomes. Participation in the MBIs was associated with significant improvements in all measured domains (all ps < 0.05), with effect sizes in the small to medium range (0.25 to 0.37, 95% CIs 0.11 to 0.56). No significant changes on these measures were found for the control group. Change in perseverative thinking was found to mediate the relationship between condition and improvement on perceived stress and anxiety/depression symptom outcomes. Contrary to our hypotheses, no differences between the intervention conditions were found. Limitations of the study included reliance on self-report data, a relatively high attrition rate and absence of a longer-term follow-up. This study provides evidence in support of the feasibility and effectiveness of brief, self-guided MBIs in a non-clinical population and suggests that reduced perseverative thinking may be a mechanism of change. Our findings provide preliminary evidence for the effectiveness of a mindfulness psychoeducation condition, without an invitation to formal mindfulness meditation practice. Further research is needed to confirm and better understand these results and to test the potential of such interventions

Homelessness in autistic women: defining the research agenda

Background: Current evidence suggests that autistic individuals are at high risk for becoming and remaining in a cycle of homelessness. Key risk factors for homelessness disproportionately affect autistic people; however, we have limited understanding of how to best support autistic individuals accessing services. This gap in the evidence base is particularly acute for autistic women. Objective: As a first step to address this gap, we aimed to (1) map gaps in knowledge and practice; (2) identify priority areas for research and (3) develop recommendations for how to implement novel research and practice in this area. Methods: We conducted a collaborative workshop with an interdisciplinary group of 26 stakeholders to address our aims. Stakeholders included autistic women with experience of homelessness, researchers, health professionals, NGO representatives, and service providers. Results and recommendations: Two research priority areas were identified to map the prevalence and demographics of autistic women experiencing homelessness, and to delineate risk and protective factors for homelessness. Priority areas for improving provision of support included staff training to improve communication, awareness of autism and building trust with service providers, and recommendations for practical provision of support by services. Conclusions: Future research is critical to increase our knowledge of the pathways leading to homelessness for autistic women, and barriers to engaging with homelessness and social services. We need to use this knowledge to develop new ways of delivering targeted and inclusive support for autistic women, which could prevent or shorten periods of homelessness

Homelessness in autistic women: Defining the research agenda

Background: Current evidence suggests that autistic individuals are at high risk for becoming and remaining in a cycle of homelessness. Key risk factors for homelessness disproportionately affect autistic people; however, we have limited understanding of how to best support autistic individuals accessing services. This gap in the evidence base is particularly acute for autistic women. Objective: As a first step to address this gap, we aimed to (1) map gaps in knowledge and practice; (2) identify priority areas for research and (3) develop recommendations for how to implement novel research and practice in this area. Methods: We conducted a collaborative workshop with an interdisciplinary group of 26 stakeholders to address our aims. Stakeholders included autistic women with experience of homelessness, researchers, health professionals, NGO representatives, and service providers. Results and recommendations: Two research priority areas were identified to map the prevalence and demographics of autistic women experiencing homelessness, and to delineate risk and protective factors for homelessness. Priority areas for improving provision of support included staff training to improve communication, awareness of autism and building trust with service providers, and recommendations for practical provision of support by services. Conclusions: Future research is critical to increase our knowledge of the pathways leading to homelessness for autistic women, and barriers to engaging with homelessness and social services. We need to use this knowledge to develop new ways of delivering targeted and inclusive support for autistic women, which could prevent or shorten periods of homelessness