Device modelling and model verification for the Euclid CCD273 detector

Euclid is one of the M-class missions selected for the next phase of ESA’s long-term Cosmic Vision programme. The primary goal of this mission is to observe the distribution and shapes of distant galaxies, with the aim of mapping and characterising the dark energy which makes up about 70% of the universe. This will be achieved by measuring the effects of weak lensing on the captured images, in terms of the distortion caused to the elipticity of galaxy shapes [1]. The e2v CCD273 was designed for the Euclid mission and is adapted from an older design (the CCD203) with changes made to improve CTE under irradiation by solar protons. Reducing the effects of radiation damage in the image sensor will result in images which have minimal distortion. This paper is focused on the on-going development and verification of 3D device models and their integration with Monte Carlo radiation damage models. Parameters such as charge interaction volume versus signal size, pixel full well capacity, and charge transfer behaviour for both the parallel and serial registers will be discussed. The main mission goals are aimed at measuring distortion due to weak lensing, so it is important to differentiate this from distortion due to radiation damage. This work will eventually lead to a method of post processing images to remove the effects of radiation damage

The Crystal Structure of the Extracellular 11-heme Cytochrome UndA Reveals a Conserved 10-heme Motif and Defined Binding Site for Soluble Iron Chelates

Members of the genus Shewanella translocate deca- or undeca-heme cytochromes to the external cell surface thus enabling respiration using extracellular minerals and polynuclear Fe(III) chelates. The high resolution structure of the first undeca-heme outer membrane cytochrome, UndA, reveals a crossed heme chain with four potential electron ingress/egress sites arranged within four domains. Sequence and structural alignment of UndA and the deca-heme MtrF reveals the extra heme of UndA is inserted between MtrF hemes 6 and 7. The remaining UndA hemes can be superposed over the heme chain of the decaheme MtrF, suggesting that a ten heme core is conserved between outer membrane cytochromes. The UndA structure has also been crystallographically resolved in complex with substrates, an Fe(III)-nitrilotriacetate dimer or an Fe(III)-citrate trimer. The structural resolution of these UndA-Fe(III)-chelate complexes provides a rationale for previous kinetic measurements on UndA and other outer membrane cytochromes

Stuart Hall and the theory and practice of articulation

In this article, I argue that the idea of articulation links three different dimensions of Stuart Hall’s work: it is central to the work of cultural politics, to the work of hegemony, and to his practice of embodied pedagogy. I claim that his approach to pedagogy entails the art of listening combined with the practice of theorising in the service of expanding who belongs to the public. This involves the work of translation, finding ways of addressing different audiences. I treat each of these aspects in turn, drawing out the salience of articulation for each and suggest that these three dimensions are themselves articulated by Hall’s commitment to the theory and practice of articulation

Pixel-level modelling and verification for the EUCLID VIS CCD

Euclid is an M-class mission selected for the next phase of ESA’s long-term Cosmic Vision programme. The mission’s primary aim is to provide insight into the physical cause of the accelerating universe which will be achieved by investigating the nature of dark energy, dark matter and gravity. The investigation will involve the measurement of the effects of intervening gravitational potentials on visible light from distant galaxies, a process known as weak gravitational lensing. The CCD273 was designed by e2v for the Euclid mission, and is based on an older design for the CCD204, with changes designed and implemented to improve operation under irradiation. These changes include a narrower buried channel in the serial register to reduce trap interactions during readout. Pixel level models have been developed to improve knowledge of charge packet distribution within the CCD273 and CCD204 using Silvaco TCAD, enabling more effective predictions to be made about device functionality before and after irradiation which can be immediately tested on both devices. This paper is focussed on latest results, with particular reference to the on-going model verification, designed to build confidence in the device models and provide feedback to further improve the modelling effort

Creating citizen-consumers? Public service reform and (un)willing selves

About the book: Postmodern theories heralded the "death of the subject", and thereby deeply contested our intuition that we are free and willing selves. In recent times, the (free) will has come under attack yet again. Findings from the neuro- and cognitive sciences claim the concept of will to be scientifically untenable, specifying that it is our brain rather than our 'self' which decides what we want to do. In spite of these challenges however, the willing self has come to take centre stage in our society: juridical and moral practices ascribing guilt, or the organization of everyday life attributing responsibilities, for instance, can hardly be understood without taking recourse to the willing subject. In this vein, the authors address topics such as the genealogy of the concept of willing selves, the discourse on agency in neuroscience and sociology, the political debate on volition within neoliberal and neoconservative regimes, approaches toward novel forms of relational responsibility as well as moral evaluations in conceptualizing autonomy

An open-source pipeline for analysing changes in microglial morphology

Changes in microglial morphology are powerful indicators of the inflammatory state of the brain. Here, we provide an open-source microglia morphology analysis pipeline that first cleans and registers images of microglia, before extracting 62 parameters describing microglial morphology. It then compares control and 'inflammation' training data and uses dimensionality reduction to generate a single metric of morphological change (an 'inflammation index'). This index can then be calculated for test data to assess inflammation, as we demonstrate by investigating the effect of short-term high-fat diet consumption in heterozygous Cx3CR1-GFP mice, finding no significant effects of diet. Our pipeline represents the first open-source microglia morphology pipeline combining semi-automated image processing and dimensionality reduction. It uses free software (ImageJ and R) and can be applied to a wide variety of experimental paradigms. We anticipate it will enable others to more easily take advantage of the powerful insights microglial morphology analysis provides

The Birth of High Mass Stars: Accretion and/or Mergers?

The observational consequences of the merger scenario for massive star formation are explored and contrasted with the gradual accumulation of mass by accretion. Protostellar mergers may produce high luminosity infrared flares lasting years to centuries followed by a luminosity decline on the Kelvin-Helmholtz time-scale of the merger product. Mergers may be surrounded by thick tori of expanding debris, impulsive wide-angle outflows, and shock induced maser and radio continuum emission. Collision products are expected to have fast stellar rotation and a large multiplicity fraction. Close encounters or mergers will produce circumstellar debris disks with an orientation that differs form that of a pre-existing disk. The extremely rare merger of two stars close to the upper-mass end of the IMF may be a possible pathway to hypernova generated gamma-ray bursters. While accretional growth can lead to the formation of massive stars in isolation or in loose clusters, mergers can only occur in high-density cluster environments. It is proposed that the outflow emerging from the OMC1 core in the Orion molecular cloud was produced by a protostellar merger that released between $10^{48}$ to $10^{49}$ ergs less than a thousand years ago

Tensor analyzing powers for 7 Li induced transfer breakup reactions

The T20 analyzing powers have been measured for the 12Sn(7Li ,8Be2a) 119In and 120Sn (7Li ,6Li*a+d) 121Sn transfer breakup reactions, using a 70 MeV beam. The data exhibit excellent agreement with the results of coupled reaction channels calculations, providing an important test of these calculations when applied to the transfer breakup reaction mechanism

Assessment of proton radiation-induced charge transfer inefficiency in the CCD273 detector for the Euclid Dark Energy Mission

Euclid is a medium class mission selected for launch in 2019, with a primary goal to study the dark universe using the weak lensing and baryonic acoustic oscillations techniques. Weak lensing depends on accurate shape measurements, therefore it is beneficial that the effects of radiation-induced charge transfer inefficiency (CTI) in the Euclid CCD over the six year mission are understood and minimised. This paper describes the initial evaluation of the tolerance to radiation induced charge transfer inefficiency (CTI) of the CCD273 produced by e2v technologies plc, making comparisons with the previous CCD selected for Euclid the CCD203. The CCD273 benefits from the inclusion of a charge injection structure for trap suppression and a reduction in the register channel width. The improvement in tolerance to radiation induced serial CTI achieved by reducing the channel width from 50 um to 20 um was measured experimentally to be a factor of 1.7, which compares well to a factor of 1.9 found using a charge volume model