Mindfulness in psychiatry - Where are we now?

Mindfulness is an increasingly popular therapeutic approach. Mindfulness-based interventions have been tried out in a wide range of mental disorders, with the strongest evidence for use in depression and anxiety. Mindfulness operates by changing the person's relationship with unhelpful thoughts and emotions. The need for home practice is both a strength and a weakness. Some find home practice too demanding and a barrier to effective utilisation of mindfulness. Others discover a set of practical tools that, once learnt, can be applied to ongoing life difficulties; in this way mindfulness may have a place in promoting recovery beyond the acute treatment of a disorder. Additionally, mindfulness may be beneficial for clinicians to promote well-being and enhance the therapeutic relationship

DNA amplification in mammalian cells

DNA amplification has been observed in mammalian cells derived from tumours and also in tissue culture cells. The initial amplification event is thought to be random and In some cases the amplified DNA contains a gene whose consequent over-expression can confer a growth advantage or reduced sensitivity to a cytotoxic compound. In tissue culture systems, specific drugs can be used to isolate cells which have previously amplified a specific gene. The mechanisms responsible for these DNA abnormalities have been difficult to study as the initial events are rare and the amplification products could previously only be visualised many cell generations after their formation. During this time secondary mechanisms may alter the structure and appearance of the amplified arrays making an evolutionary interpretation of the amplification difficult. Until recently, only indirect methods were available to study the structure of amplified arrays but advances in fluorescent in situ hybridisation of metaphase chromosomes have allowed direct visualisation of very early gene amplification events. Part of this thesis describes an attempt to construct a model cell line in which a single predetermined locus could be amplified simultaneously throughout a cell population in a controlled manner. Cosmids covering the monkey CAD locus were available and one was used to construct a homologous replacement fragment containing an SV40 replication origin and a dominant selectable marker. The fragment was transfected into ts-COS cells and if a cell line could have been isolated in which the fragment had integrated by homologous recombination, it may have been possible to over-replicate the locus by a shift to the permissive temperature to mimic the 'onionskin' model of gene amplification. Other chapters of this thesis are concerned with the evolution and stability of amplified DNA and also the analysis of amplified DNA by in situ hybridisation on human metaphase chromosomes. Amplified DNA is lost very rapidly from PALA- resistant mutants selected in a single selection step but in mutants selected in several steps of increasing drug concentration the amplified genes are lost more slowly, if at all. PALA resistance in human cells has not been extensively investigated and, following recent advances in the understanding of early events in gene amplification provided by in situ hybridisation analysis of PALA-resistant BHK ceils, a human system would provide a more accessible genome for further experiments

Reflection high-energy electron diffraction experimental analysis of polycrystalline MgO films with grain size and orientation distributions

Analysis of biaxial texture of MgO films grown by ion-beam-assisted deposition (IBAD) has been performed using a quantitative reflection high-energy electron diffraction (RHEED) based method. MgO biaxial texture is determined by analysis of diffraction spot shapes from single RHEED images, and by measuring the width of RHEED in-plane rocking curves for MgO films grown on amorphous Si3N4 by IBAD using 750 eV Ar+ ions, at 45° incidence angle, and MgO e-beam evaporation. RHEED-based biaxial texture measurement accuracy is verified by comparison with in-plane and out-of-plane orientation distribution measurements made using transmission electron microscopy and x-ray rocking curves. In situ RHEED measurements also enable the analysis of the evolution of the biaxial texture which narrows with increasing film thickness. RHEED-based measurements of IBAD MgO biaxial texture show that the minimum in-plane orientation distribution depends on the out-of-plane orientation distribution, and indicates that the minimum obtainable in-plane orientation on distribution is 2°

Multi-Epoch 3D-Mapping-Aided Positioning using Bayesian Filtering Techniques

In dense urban areas, conventional GNSS does not perform satisfactorily, sometimes resulting in errors of tens of metres. This is due to the blocking, reflection and diffraction of GNSS satellite signals by obstructions such as buildings and moving vehicles. The 3D mapping data of buildings can be used to predict which GNSS signals are line-of-sight (LOS) and which are non-line-of-sight (NLOS). These data have been shown to greatly improve GNSS performance in urban environments. Location-based services typically use single-epoch positioning, while all pedestrian and vehicle navigation applications use filtered solutions. Filtering can reduce the impact of noise-like errors on the position solution. Kalman filtering-based solutions have been adopted as one of the standard algorithms for GNSS navigation in many different products, and particle filtering has been demonstrated by several research groups. This paper mainly investigates the performance of different filtering algorithms combined with 3D-mapping-aided (3DMA) techniques. In addition to the Kalman filter and particle filter, the grid filter is also considered. In contrast to a particle filter, the hypotheses of a grid filter are uniformly distributed (forming a grid), but with different likelihoods, which better fits the physics of the problem. At the same time, this allows the current UCL’s single-epoch 3DMA GNSS positioning algorithm to be easily extended to multi-epoch situations. This paper then compares the performance of these continuous positioning algorithms in urban environments. The datasets used for testing include pedestrian and vehicle navigation data, covering two main application scenarios that often appear in cities. Pedestrian navigation data is static, and was collected in the City of London using a u-blox EVK M8T GNSS receiver. The vehicle navigation data consists of GPS and Galileo measurements, collected in Canary Wharf by a trials van with a Racelogic Labsat 3 GNSS front end. Subsequently, these data are fed into several single- and multi-epoch filtering algorithms, including single-epoch conventional GNSS, single-epoch 3DMA GNSS, conventional extended Kalman Filter (EKF), conventional particle filter (PF), 3DMA GNSS particle filter (PF), and 3DMA GNSS grid filter (GF). The results show that filtering has a greater impact on the results of mobile positioning with significant movement compared to static positioning. In vehicle tests, the conventional multi-epoch GNSS algorithms improve positioning accuracy by more than 40% compared to single-epoch GNSS, whereas in static positioning they deliver a limited improvement. 3DMA GNSS significantly improves positioning accuracy in the denser environments, but provides little benefit in more open areas. The 3DMA GNSS techniques and the filtering algorithms benefit each other. The former provides the latter with a better position solution at the measurement update step, while the latter in turn repays the former with a better initial position and a smaller search area. In vehicle tests at Canary Wharf, the 3DMA GNSS filtering reduces the overall solution error by approximately 50% and 40% compared to the single-epoch 3DMA GNSS and filtered conventional GNSS, respectively. Thus, multi-epoch 3DMA GNSS filtering should bring maximum benefit to mobile positioning in dense environments. The results from both datasets also confirm that the performance of 3DMA GNSS particle filtering and grid filtering are similar in terms of positional accuracy. In terms of efficiency, 3DMA GNSS grid filtering uses fewer particles to achieve the same coverage of the search area as particle filtering