11,185 research outputs found

    ROSAT observations of two 'cooling flow' EMSS Galaxies

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    We present ROSAT observations of two luminous L~10^44 erg/s EMSS galaxies, MS1019+5139 and MS1209+3917, previously classified as 'cooling flow' galaxies. MS1019+5139 does not appear to be spatially extended (<13 kpc) while its spectrum is well fit by a power law with Gamma = 1.73 +0.19-0.18; X-ray variability on a timescale of ~ years is also clearly detected. MS1209+3917 shows no evidence of spatial extension (<50 kpc) but it shows variability, while its spectrum can be fit with thermal bremsstrahlung emission (kT=1.8 +0.9-0.4 keV) or a power law model (Gamma = 2.50 +0.44-0.42, but with excess photoelectric absorption above the Galactic value). All the above argue against thermal emission from a group of galaxies or a galaxy but in favour of an AGN (possibly BL Lac) interpretation. We conclude that no 'normal' galaxies with high X-ray luminosities have yet been detected in the EMSS survey that could be significant contributors to the X-ray background.Comment: 6 pages, LaTeX, 6 postscript figures included, to appear in MNRA

    Causes and explanation of ''breakthrough phenomenon'' when LEM cooling system sublimator is fed with chlorinated feedwater

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    Comparison of chlorine or iodine use as feedwater bactericides in lunar excursion module cooling system sublimato

    A Note on Doubly Warped Product Contact CR-Submanifolds in trans-Sasakian Manifolds

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    Warped product CR-submanifolds in Kaehlerian manifolds were intensively studied only since 2001 after the impulse given by B.Y. Chen. Immediately after, another line of research, similar to that concerning Sasakian geometry as the odd dimensional version of Kaehlerian geometry, was developed, namely warped product contact CR-submanifolds in Sasakian manifolds. In this note we proved that there exists no proper doubly warped product contact CR-submanifolds in trans-Sasakian manifolds.Comment: 5 Latex page

    BDSIM-Beamline Simulation Toolkit Based on GEANT4

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    http://cern.ch/AccelConf/e06/PAPERS/WEPCH124.PDFInternational audienceBDSIM is a code that combines accelerator-style par- ticle tracking with traditional Geant-style tracking based on Runge-Kutta techniques. This approach means that particle beams can be tracked efficiently when inside the beampipe, while also enabling full Geant4 processes when beam-particles interact with beamline apertures. Tracking of the resulting secondary particles is automatic. The code is described, including a new MAD-style interface and new geometry description, and key performance parameters are listed

    Abundant and equipotent founder cells establish and maintain acute lymphoblastic leukaemia

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    High frequencies of blasts in primary acute lymphoblastic leukaemia (ALL) samples have the potential to induce leukaemia and to engraft mice. However, it is unclear how individual ALL cells each contribute to drive leukaemic development in a bulk transplant and the extent to which these blasts vary functionally. We used cellular barcoding as a fate mapping tool to track primograft ALL blasts in vivo. Our results show that high numbers of ALL founder cells contribute at similar frequencies to leukaemic propagation over serial transplants, without any clear evidence of clonal succession. These founder cells also exhibit equal capacity to home and engraft to different organs, although stochastic processes may alter the composition in restrictive niches. Our findings enhance the stochastic stem cell model of ALL by demonstrating equal functional abilities of singular ALL blasts and show that successful treatment strategies must eradicate the entire leukaemic cell population

    Hidden symmetries and Killing tensors on curved spaces

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    Higher order symmetries corresponding to Killing tensors are investigated. The intimate relation between Killing-Yano tensors and non-standard supersymmetries is pointed out. In the Dirac theory on curved spaces, Killing-Yano tensors generate Dirac type operators involved in interesting algebraic structures as dynamical algebras or even infinite dimensional algebras or superalgebras. The general results are applied to space-times which appear in modern studies. One presents the infinite dimensional superalgebra of Dirac type operators on the 4-dimensional Euclidean Taub-NUT space that can be seen as a twisted loop algebra. The existence of the conformal Killing-Yano tensors is investigated for some spaces with mixed Sasakian structures.Comment: 12 pages; talk presented at Group 27 Colloquium, Yerevan, Armenia, August 200

    Update on the Status of BDSIM

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    International audienceRecent updates to the status of the BDSIM particle tracking code are presented. In particular, we describe efforts to combine the secondary particle generation of BDSIM with the wakefield calculations of Placet in order to quantify backgrounds from col- limating elements in the beam delivery system of the International Linear Collider. Further recent updates to BDSIM are also introduced

    Knowledge, attitudes, and practices associated with vitamin D supplementation: A cross-sectional online community survey of adults in the UK

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    OBJECTIVE: Assess knowledge, attitudes, and practices (KAPs) of a diverse population. Identify barriers and facilitators that inform routine vitamin D supplementation and self-care in the community setting. DESIGN: Cross-sectional online voluntary survey. Electronic survey link published on college Qualtrics platform and advertised widely. Study information provided with Participant Information Sheet. SETTING AND PARTICIPANTS: 556 community dwelling adults across the UK. METHODS: The overarching study included two phases, incorporating quantitative and qualitative methodologies. This paper reports findings from the first phase of the FABCOM-D (Facilitators and Barriers to Community (Healthy) Vitamin D status) study. Online survey questions were iteratively developed after background literature searches and piloted to ensure clarity and ease of understanding. Survey responses summarised using frequencies and percentages, and univariable and multivariable logistic regression models explored for any association. A p-value less than 0.05 was considered statistically significant. The Checklist for Reporting Results of Internet E-Surveys guided reporting. Statistical analysis performed using IBM SPSS software. MAIN OUTCOME MEASURES: Awareness of vitamin D information sources, health benefits and testing. Attitudes to supplementation, sun exposure and fortification. RESULTS: Three quarters of the community had some awareness of vitamin D and around half were taking supplements. The two most trusted sources of information included health professionals and the NHS website. Participants were willing to pay for supplements, supporting a self-care agenda. With increasing age, there was significant reduced intake of vitamin D supplements. This aspect needs to be explored further as this could be a concern in deficiency status in the elderly. There was acceptance of food fortification but uncertainty on how to balance food intake with supplementation. CONCLUSION: We were successful in eliciting views on KAPs around vitamin D from a community population including a large proportion of Black and Minority Ethnic individuals. The community wanted information and guidance to help manage individual vitamin D status, especially for high-risk groups, and on balancing supplementation, food fortification and sun exposure
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