Room Temperature Electrical Detection of Spin Coherence in C60

An experimental demonstration of electrical detection of coherent spin motion of weakly coupled, localized electron spins in thin Fullerene C60 films at room temperature is presented. Pulsed electrically detected magnetic resonance experiments on vertical photocurrents through Al/C60/ZnO samples showed that an electron spin Rabi oscillation is reflected by transient current changes. The nature of possible microscopic mechanisms responsible for this spin to charge conversion as well as its implications for the readout of endohedral Fullerene (N@C60) spin qubits are discussed.Comment: 4 pages, 3 figure

Quark condensate in one-flavor QCD

We compute the condensate in QCD with a single quark flavor using numerical simulations with the overlap formulation of lattice fermions. The condensate is extracted by fitting the distribution of low lying eigenvalues of the Dirac operator in sectors of fixed topological charge to the predictions of Random Matrix Theory. Our results are in excellent agreement with estimates from the orientifold large-N_c expansion.Comment: 12 pages, 4 figures, REVTeX4, v2: Small changes, extended introduction, published versio

Exploring positive adjustment in HIV positive African women living in the UK

This published version of this article has been made available through Open Access by the Brunel University Open Access Publishing Fund and can be accessed at the link below - Copyright @ 2011 Taylor & FrancisResearch into living with HIV/AIDS has to date mainly focused on quality of life and there is little on the adjustment process for this group. The numbers of African women living with HIV/AIDS in the UK is growing and yet little is known about the adjustment experience for these women. This study explored aspects of positive adjustment to living with HIV/AIDS among a sample of African women living in London, UK. Transcripts of semi-structured interviews with 12 women were analysed using interpretative phenomenological analysis (IPA). Two superordinate themes emerged inductively from the data: positive changes in coping (subthemes: positive interpretation of their situation and positive behavioural changes) and positive growth since the HIV diagnosis (subthemes: changes in the value of life and, changes in goals and opportunities). While these women acknowledged the negative impact of living with HIV/AIDS, all participants mentioned changes in health behaviours to help regain mastery of their lives and comparing with others better-off and worse-off was used to enhance self-esteem and view their situation positively. The data show evidence for Taylor's Cognitive Adaptation Theory

COMPARISON OF ORTHODOX WITH FIBREOPTIC OROTRACHEAL INTUBATION UNDER TOTAL I.V. ANAESTHESIA

Fibreoptic orotracheal intubation was compared with orthodox laryngoscopy and tracheal intubation using a total i.v. technique with propofol in 60 ASA I and II patients. There was no significant difference between the two techniques in haemodynamic profile (before, during and following the intubation procedure) and incidence of postoperative sore throat. Minimal oxygen saturation was 96% during the study; maximal end-tidal PCO2 after intubation was 5.4 kPa. Intubation time was faster (P < 0.01) in the orthodox group (30.7 (SEM 2.3) s) than in the fibreoptic group (52.7 (4.8) s

In situ correction of recombination effects in ultra-high dose rate irradiations with protons.

Background.At the Center for Proton Therapy at the Paul Scherrer Institute (PSI) the delivery of proton radiation is controlled via gas-based ionization chambers: the beam is turned off when a certain amount of preset charge has been collected. At low dose rates the charge collection efficiency in these detectors is unity, at ultra-high dose rates it is less due to induced charge recombination effects. If not corrected, the latter would lead to an overdosage.Purpose.In the scope of this work, we developed a novel approach to anin situcharge recombination correction for our dose defining detectors, when irradiated with a proton beam at ultra-high dose rates. This approach is based on the Two-Voltage-Method.Methods.We have translated this method to two separate devices operated simultaneously at different conditions. By doing so, the charge collection losses can be corrected directly and without the need for empirical correction values. This approach has been tested at ultra-high dose rates; proton beam was delivered by the COMET cyclotron to Gantry 1 at PSI.Results.We were able to correct the charge losses caused by recombination effects at local beam currents of approximately 700 nA (i.e. instantaneous dose rate of 3600 Gy s-1at isocenter). The corrected collected charges in our gaseous detectors were compared against recombination-free measurements with a Faraday cup. The ratio of both quantities shows no significant dose rate dependence within their respective combined uncertainties.Conclusions. Correcting recombination effects in our gas-based detectors with the novel method greatly eases the handling of Gantry 1 as 'FLASH test bench'. Not only is the application of a preset dose more accurate compared to using an empirical correction curve, also the re-determination of empirical correction curves in the case of a beam phase space change can be omitted

Diquark effects in light baryon correlators from lattice QCD

We study the role of diquarks in light baryons through point to point baryon correlators. We contrast results from quenched simulations with ones with two flavors of dynamical overlap fermions. The scalar, pseudoscalar and axial vector diquarks are combined with light quarks to form color singlets. The quenched simulation shows large zero mode effects in correlators containing the scalar and pseudoscalar diquark. The two scalar diquarks created by gamma_5 and gamma_0gamma_5 lead to different behavior in baryon correlators, showing that the interaction of diquarks with the third light quark matters: we do not see an isolated diquark. In our quark mass range, the scalar diquark created by gamma_5 seems to play a greater role than the others.Comment: 12 pages, 11 figure

Endothelial Progenitors Exist within the Kidney and Lung Mesenchyme

The renal endothelium has been debated as arising from resident hemangioblast precursors that transdifferentiate from the nephrogenic mesenchyme (vasculogenesis) and/or from invading vessels (angiogenesis). While the Foxd1-positive renal cortical stroma has been shown to differentiate into cells that support the vasculature in the kidney (including vascular smooth muscle and pericytes) it has not been considered as a source of endothelial cell progenitors. In addition, it is unclear if Foxd1-positive mesenchymal cells in other organs such as the lung have the potential to form endothelium. This study examines the potential for Foxd1-positive cells of the kidney and lung to give rise to endothelial progenitors. We utilized immunofluorescence (IF) and fluorescence-activated cell sorting (FACS) to co-label Foxd1-expressing cells (including permanently lineage-tagged cells) with endothelial markers in embryonic and postnatal mice. We also cultured FACsorted Foxd1-positive cells, performed in vitro endothelial cell tubulogenesis assays and examined for endocytosis of acetylated low-density lipoprotein (Ac-LDL), a functional assay for endothelial cells. Immunofluorescence and FACS revealed that a subset of Foxd1-positive cells from kidney and lung co-expressed endothelial cell markers throughout embryogenesis. In vitro, cultured embryonic Foxd1-positive cells were able to differentiate into tubular networks that expressed endothelial cell markers and were able to endocytose Ac-LDL. IF and FACS in both the kidney and lung revealed that lineage-tagged Foxd1-positive cells gave rise to a significant portion of the endothelium in postnatal mice. In the kidney, the stromal-derived cells gave rise to a portion of the peritubular capillary endothelium, but not of the glomerular or large vessel endothelium. These findings reveal the heterogeneity of endothelial cell lineages; moreover, Foxd1-positive mesenchymal cells of the developing kidney and lung are a source of endothelial progenitors that are likely critical to patterning the vasculature. © 2013 Sims-Lucas et al

Modelling the Recurrent Nova CI Aql in Quiescence

We present detailed photometric investigations of the recurrent nova CI Aql. New data obtained after the 2000 outburst are used to derive a 3D geometrical model of the system. The resulting light curves clearly indicate the existence of an asymmetric spray around the accretion disk, as claimed in the past e.g. for the super-soft X-ray source CAL87 in the LMC. The simulated light curves give us the mass transfer rates varying from \dot M ~ 2.5 x 10^{-8} M_\odot / yr in 1991-1996 to 5.5 x 10^{-8} < \dot M < 1.5 x 10^{-7}M_\odot / yr in 2001/2002. The distance and the interstellar foreground extinction resulting from the model are 1.55 kpc and E(B-V) = 0.98 respectively. During fast photometry sequences in 2002 short timescale variations (t ~ 13 minutes) of the mass loss are found. Moreover a change in the orbital period of the system is detectable and results in a mass loss of 2.2 x 10^{-6} < \Delta M < 5.7 x 10^{-6} M_\odot during the nova explosion.Comment: 9 pages 14 eps figures, to appear in Astron. & Astrophy

Calibration of GRB Luminosity Relations with Cosmography

For the use of Gamma-Ray Bursts (GRBs) to probe cosmology in a cosmology-independent way, a new method has been proposed to obtain luminosity distances of GRBs by interpolating directly from the Hubble diagram of SNe Ia, and then calibrating GRB relations at high redshift. In this paper, following the basic assumption in the interpolation method that objects at the same redshift should have the same luminosity distance, we propose another approach to calibrate GRB luminosity relations with cosmographic fitting directly from SN Ia data. In cosmography, there is a well-known fitting formula which can reflect the Hubble relation between luminosity distance and redshift with cosmographic parameters which can be fitted from observation data. Using the Cosmographic fitting results from the Union set of SNe Ia, we calibrate five GRB relations using GRB sample at $z\leq1.4$ and deduce distance moduli of GRBs at $1.4< z \leq 6.6$ by generalizing above calibrated relations at high redshift. Finally, we constrain the dark energy parameterization models of the Chevallier-Polarski-Linder (CPL) model, the Jassal-Bagla-Padmanabhan (JBP) model and the Alam model with GRB data at high redshift, as well as with the Cosmic Microwave Background radiation (CMB) and the baryonic acoustic oscillation (BAO) observations, and we find the $\Lambda$CDM model is consistent with the current data in 1-$\sigma$ confidence region.Comment: 15 pages, 4 figures, 2 tables; accepted for publication in IJMP

UV excess measures of accretion onto young very low-mass stars and brown dwarfs

Low-resolution spectra from 3000-9000 AA of young low-mass stars and brown dwarfs were obtained with LRIS on Keck I. The excess UV and optical emission arising in the Balmer and Paschen continua yields mass accretion rates ranging from 2e-12 to 1e-8 Mo/yr. These results are compared with {\it HST}/STIS spectra of roughly solar-mass accretors with accretion rates that range from 2e-10 to 5e-8 Mo/yr. The weak photospheric emission from M-dwarfs at <4000 A leads to a higher contrast between the accretion and photospheric emission relative to higher-mass counterparts. The mass accretion rates measured here are systematically 4-7 times larger than those from H-alpha emission line profiles, with a difference that is consistent with but unlikely to be explained by the uncertainty in both methods. The accretion luminosity correlates well with many line luminosities, including high Balmer and many He I lines. Correlations of the accretion rate with H-alpha 10% width and line fluxes show a large amount of scatter. Our results and previous accretion rate measurements suggest that accretion rate is proportional to M^(1.87+/-0.26) for accretors in the Taurus Molecular Cloud.Comment: 13 pages text, 15 tables, 14 figures. Accepted by Ap