Oxidation studies of some refractory metals

Samples of niobium, tantalum, molybdenum and tungsten metals have been given phosphided cases by heating in a phosphorous atmosphere. The samples were subsequently exposed to air at an elevated temperature. In tests at 800°C, the phosphided samples resisted air oxidation markedly compared to the pure untreated samples. The phosphided cases were only a few microns thick yet oxidation resistance of all these samples extended for several hours. Phosphided samples with 90° edges did not resist oxidation at the edges as well as rounded edge samples

Noise Properties of Superconducting Coplanar Waveguide Microwave Resonators

We have measured noise in thin-film superconducting coplanar waveguide resonators. This noise appears entirely as phase noise, equivalent to a jitter of the resonance frequency. In contrast, amplitude fluctuations are not observed at the sensitivity of our measurement. The ratio between the noise power in the phase and amplitude directions is large, in excess of 30 dB. These results have important implications for resonant readouts of various devices such as detectors, amplifiers, and qubits. We suggest that the phase noise is due to two-level systems in dielectric materials.Comment: 4 pages, 3 figures, accepted for publication in Applied Physics Letter

Reading Mark 4:35-41 : a study of student discourses in the School of Theology, The University of Natal, Pietermaritzburg.

Thesis (Ph.D.)-University of Natal, Pietermaritzburg,2001.In this study I present the results of interviews conducted with thirty-four students in the School of Theology, University of Natal, Pietermaritzburg. In the following eight chapters I have provided a description of the discourses and discourse communities in the School of Theology which have emerged from my analysis of the data collected from these interviews. These discourses fall into three categories: The primary discourse, which is the result of the students' socialisation within their family and the primary community structures of their childhood, the secondary discourse ensuing from their educational and denominational backgrounds and their relationships with their teachers and the hierarchy of their denominations and the tertiary discourse of critical biblical exegesis which they encounter in their studies in the School of Theology. The product of this encounter is a clash of discourses which challenges the students both academically, leading to poor academic performance on the part of many students, and spiritually, leading to such dire consequences as nervous breakdowns or the loss of faith and vocation. In describing this clash of discourses I include a plea for the management and staff of the School of Theology to provide both academic and spiritual support for the students' in their attempt to face and overcome the considerable challenges of studying in the School of Theology

Prescribing in a paediatric emergency: A PERUKI survey of prescribing and resuscitation aids

Aim: The aim was to investigate the use of paper-based and electronic prescribing and resuscitation aids in paediatric emergency care from a departmental and individual physician perspective. Methods: A two-stage web-based self-report questionnaire was performed. In stage (i), a lead investigator at PERUKI sites completed a department-level survey; in stage (ii), individual physicians recorded their personal practice. Results: The site survey was completed by 46/54 (85%) of PERUKI sites. 198 physicians completed the individual physicians' survey. Individual physicians selected the use of formulary apps for checking of medication dosages nearly as often as hardcopy formularies. The APLS WETFLAG calculation and hardcopy aids were widely accepted in both surveys. A third of sites accepted and half of the individual physicians selected resuscitation apps on the personal mobile device as paediatric resuscitation aids. Conclusion: Our survey shows a high penetrance of the British National Formulary app, a success of NHS digital policy and strategy. Despite potential advantages, many physicians in our survey do not use resuscitation apps. Reluctance to engage with apps is likely to be multifactorial and includes human factors. These obstacles need to be overcome to create a digital healthcare culture

Dynamic DNA cytosine methylation in the Populus trichocarpa genome: tissue-level variation and relationship to gene expression

This is the publisher’s final pdf. The published article is copyrighted by BioMed Central Ltd and can be found at: http://www.biomedcentral.com/.Background: DNA cytosine methylation is an epigenetic modification that has been implicated in many biological processes. However, large-scale epigenomic studies have been applied to very few plant species, and variability in methylation among specialized tissues and its relationship to gene expression is poorly understood. \ud \ud Results: We surveyed DNA methylation from seven distinct tissue types (vegetative bud, male inflorescence [catkin], female catkin, leaf, root, xylem, phloem) in the reference tree species black cottonwood (Populus trichocarpa). Using 5-methyl-cytosine DNA immunoprecipitation followed by Illumina sequencing (MeDIP-seq), we mapped a total of 129,360,151 36- or 32-mer reads to the P. trichocarpa reference genome. We validated MeDIP-seq results by bisulfite sequencing, and compared methylation and gene expression using published microarray data. Qualitative DNA methylation differences among tissues were obvious on a chromosome scale. Methylated genes had lower expression than unmethylated genes, but genes with methylation in transcribed regions ("gene body methylation") had even lower expression than genes with promoter methylation. Promoter methylation was more frequent than gene body methylation in all tissues except male catkins. Male catkins differed in demethylation of particular transposable element categories, in level of gene body methylation, and in expression range of genes with methylated transcribed regions. Tissue-specific gene expression patterns were correlated with both gene body and promoter methylation. \ud \ud Conclusions: We found striking differences among tissues in methylation, which were apparent at the chromosomal scale and when genes and transposable elements were examined. In contrast to other studies in plants, gene body methylation had a more repressive effect on transcription than promoter methylation

MAIA - A machine learning assisted image annotation method for environmental monitoring and exploration

Zurowietz M, Langenkämper D, Hosking B, Ruhl H, Nattkemper TW. MAIA - A machine learning assisted image annotation method for environmental monitoring and exploration . PLoS ONE. 2018;13(11): e0207498.Digital imaging has become one of the most important techniques in environmental monitoring and exploration. In the case of the marine environment, mobile platforms such as autonomous underwater vehicles (AUVs) are now equipped with high-resolution cameras to capture huge collections of images from the seabed. However, the timely evaluation of all these images presents a bottleneck problem as tens of thousands or more images can be collected during a single dive. This makes computational support for marine image analysis essential. Computer-aided analysis of environmental images (and marine images in particular) with machine learning algorithms is promising, but challenging and different to other imaging domains because training data and class labels cannot be collected as efficiently and comprehensively as in other areas. In this paper, we present Machine learning Assisted Image Annotation (MAIA), a new image annotation method for environmental monitoring and exploration that overcomes the obstacle of missing training data. The method uses a combination of autoencoder networks and Mask Region-based Convolutional Neural Network (Mask R-CNN), which allows human observers to annotate large image collections much faster than before. We evaluated the method with three marine image datasets featuring different types of background, imaging equipment and object classes. Using MAIA, we were able to annotate objects of interest with an average recall of 84.1% more than twice as fast as compared to “traditional” annotation methods, which are purely based on software-supported direct visual inspection and manual annotation. The speed gain increases proportionally with the size of a dataset. The MAIA approach represents a substantial improvement on the path to greater efficiency in the annotation of large benthic image collections

Deleuze, Freud and the Three Syntheses

The aim of this paper is to provide a close reading of Deleuze's complex account of Freud's Beyond the Pleasure Principle in Difference and Repetition. The first part provides a reading of Beyond the Pleasure Principle itself, showing why Freud feels the need to develop a transcendental account of repetition. In the second, I show the limitations of Freud's account, drawing on the work of Weismann to argue that Freud's transcendental model mischaracterises repetition. In the third part, I show how Freud's account of the death drive is shadowed by Deleuze's own non-representational transcendental account