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°

New measurements of the cosmic infrared background fluctuations in deep Spitzer/IRAC survey data and their cosmological implications

We extend previous measurements of cosmic infrared background (CIB) fluctuations to ~ 1 deg using new data from the Spitzer Extended Deep Survey. Two fields, with depths of ~12 hr/pixel over 3 epochs, are analyzed at 3.6 and 4.5 mic. Maps of the fields were assembled using a self-calibration method uniquely suitable for probing faint diffuse backgrounds. Resolved sources were removed from the maps to a magnitude limit of AB mag ~ 25, as indicated by the level of the remaining shot noise. The maps were then Fourier-transformed and their power spectra were evaluated. Instrumental noise was estimated from the time-differenced data, and subtracting this isolates the spatial fluctuations of the actual sky. The power spectra of the source-subtracted fields remain identical (within the observational uncertainties) for the three epochs indicating that zodiacal light contributes negligibly to the fluctuations. Comparing to 8 mic power spectra shows that Galactic cirrus cannot account for the fluctuations. The signal appears isotropically distributed on the sky as required for an extragalactic origin. The CIB fluctuations continue to diverge to > 10 times those of known galaxy populations on angular scales out to < 1 deg. The low shot noise levels remaining in the diffuse maps indicate that the large scale fluctuations arise from the spatial clustering of faint sources well below the confusion noise. The spatial spectrum of these fluctuations is in reasonable agreement with an origin in populations clustered according to the standard cosmological model (LCDM) at epochs coinciding with the first stars era.Comment: ApJ, to be publishe

Arendt and political realism: towards a realist account of political judgement

This article argues that Hannah Arendt’s thought can offer significant insights on political judgement for realism in political theory. We identify a realist position which emphasises the need to account for how humans judge politically, contra moralist tendencies to limit its exercise to rational standards, but which fails to provide a sufficient conception of its structure and potential. Limited appeals to political judgement render the realist defence of the political elusive, and compromise the endeavour to offer a meaningful alternative to the moralist tendency to displace politics. The potential and limitations of realist discussions on judgement are made visible in relation to proto-realists Judith Shklar and Isaiah Berlin. In seeking to enrich the realist conception of the political, the article introduces the displacement critique found in the neglected Arendtian ‘realism’. It also provides the foundations for a distinctly realist account of political judgement which, we argue, requires elaboration along two dimensions: the social coding of political judgement and the political capacities that help judgement build a suitable political sphere

Voluntary Counselling, HIV Testing and Adjunctive Cotrimoxazole Reduces Mortality in Tuberculosis Patients in Thyolo, Malawi.

OBJECTIVES: To assess the feasibility and effectiveness of voluntary counselling, HIV testing and adjunctive cotrimoxazole in reducing mortality in a cohort of tuberculosis (TB) patients registered under routine programme conditions in a rural district of Malawi. DESIGN: 'Before' and 'after' cohort study using historical controls. METHODS: Between 1 July 1999 and 30 June 2000 all TB patients were started on standardized anti-TB treatment, and offered voluntary counselling and HIV testing (VCT). Those found to be HIV-positive were offered cotrimoxazole at a dose of 480 mg twice daily, provided there were no contraindications. Side-effects were monitored clinically. End-of-treatment outcomes in this cohort (intervention group) were compared with a cohort registered between 1 July 1998 and 30 June 1999 in whom VCT and cotrimoxazole was not offered (control group). FINDINGS: A total of 1986 patients was registered in the study: 1061 in the intervention group and 925 in the control cohort. In the intervention group, 1019 (96%) patients were counselled pre-test, 964 (91%) underwent HIV testing and 938 (88%) were counselled post-test. The overall HIV-seroprevalence rate was 77%. A total of 693 patients were given cotrimoxazole of whom 14 (2%) manifested minor dermatological reactions. The adjusted relative risk of death in the intervention group compared with the control group was 0.81 (P < 0.001). The number needed to treat with VCT and adjunctive cotrimoxazole to prevent one death during anti-TB treatment was 12.5. INTERPRETATION: This study shows that VCT and adjunctive cotrimoxazole is feasible, safe and reduces mortality rates in TB patients under routine programme conditions

Angular dependent vortex pinning mechanisms in YBCO coated conductors and thin films

We present a comparative study of the angular dependent critical current density in YBa2Cu3O7 films deposited on IBAD MgO and on single crystal MgO and SrTiO3 substrates. We identify three angular regimes where pinning is dominated by different types of correlated and uncorrelated defects. We show that those regimes are present in all cases, indicating that the pinning mechanisms are the same, but their extension and characteristics are sample dependent, reflecting the quantitative differences in texture and defect density. In particular, the more defective nature of the films on IBAD turns into an advantage as it results in stronger vortex pinning, demonstrating that the critical current density of the films on single crystals is not an upper limit for the performance of the IBAD coated conductors.Comment: 14 pages, 3 figures. Submitted to AP

Children, family and the state : revisiting public and private realms

The state is often viewed as part of the impersonal public sphere in opposition to the private family as a locus of warmth and intimacy. In recent years this modernist dichotomy has been challenged by theoretical and institutional trends which have altered the relationship between state and family. This paper explores changes to both elements of the dichotomy that challenge this relationship: a more fragmented family structure and more individualised and networked support for children. It will also examine two new elements that further disrupt any clear mapping between state/family and public/private dichotomies: the third party role of the child in family/state affairs and children's application of virtual technology that locates the private within new cultural and social spaces. The paper concludes by examining the rise of the 'individual child' hitherto hidden within the family/state dichotomy and the implications this has for intergenerational relations at personal and institutional levels

Determination of the Far-Infrared Cosmic Background Using COBE/DIRBE and WHAM Data

Determination of the cosmic infrared background (CIB) at far infrared wavelengths using COBE/DIRBE data is limited by the accuracy to which foreground interplanetary and Galactic dust emission can be modeled and subtracted. Previous determinations of the far infrared CIB (e.g., Hauser et al. 1998) were based on the detection of residual isotropic emission in skymaps from which the emission from interplanetary dust and the neutral interstellar medium were removed. In this paper we use the Wisconsin H-alpha Mapper (WHAM) Northern Sky Survey as a tracer of the ionized medium to examine the effect of this foreground component on determination of the CIB. We decompose the DIRBE far infrared data for five high Galactic latitude regions into H I and H-alpha correlated components and a residual component. We find the H-alpha correlated component to be consistent with zero for each region, and we find that addition of an H-alpha correlated component in modeling the foreground emission has negligible effect on derived CIB results. Our CIB detections and 2 sigma upper limits are essentially the same as those derived by Hauser et al. and are given by nu I_nu (nW m-2 sr-1) < 75, < 32, 25 +- 8, and 13 +- 3 at 60, 100, 140, and 240 microns, respectively. Our residuals have not been subjected to a detailed anisotropy test, so our CIB results do not supersede those of Hauser et al. We derive upper limits on the 100 micron emissivity of the ionized medium that are typically about 40% of the 100 micron emissivity of the neutral atomic medium. This low value may be caused in part by a lower dust-to-gas mass ratio in the ionized medium than in the neutral medium, and in part by a shortcoming of using H-alpha intensity as a tracer of far infrared emission.Comment: 38 pages, 8 figures. Accepted for publication in Ap

Citizens without nations

To broach the question of whether citizenship could exist without (or beyond) community, this paper discusses genealogies of citizenship as membership that binds an individual to the community of birth (of the self or a parent). It is birthright as fraternity that blurs the boundary between citizenship and nationality. After briefly discussing recent critical studies on birthright citizenship (whether it is civic or ethnic or blood or soil) by Ayelet Shachar and Jacqueline Stevens, the paper discusses three critical genealogies of the relationship between birthright and citizenship by Max Weber, Hannah Arendt, and Michel Foucault. Although each provides a critical perspective into the question, Weber reduces citizenship to fraternity with nation and Arendt reduces citizenship to fraternity with the state. It is Foucault who illustrates racialization of fraternity as the connection between citizenship and nationality. Yet, since Foucault limits his genealogical investigations to the 18th and 19th centuries, a genealogy of fraternity of what he calls an immense biblical and Greek tradition remains for Derrida to articulate as a question of citizenship