The Swift X-ray telescope BURROWS, David N; HILL, J. E; CHINCARINI, G ...
Space science reviews,
10/2005, Volume:
120, Issue:
3-4
Journal Article
Peer reviewed
he Swift Gamma-Ray Explorer is designed to make prompt multiwavelength observations of gamma-ray bursts (GRBs) and GRB afterglows. The X-ray telescope (XRT) enables Swift to determine GRB positions ...with a few arcseconds accuracy within 100 s of the burst onset. The XRT utilizes a mirror set built for JET-X and an XMM-Newton/EPIC MOS CCD detector to provide a sensitive broad-band (0.2-10 keV) X-ray imager with effective area of > 120 cm^sup 2^ at 1.5 keV, field of view of 23.6 × 23.6 arcminutes, and angular resolution of 18 arcseconds (HPD). The detection sensitivity is 2×10^sup -14^ erg cm^sup -2^ s^sup -1^ in 10^sup 4^ s. The instrument is designed to provide automated source detection and position reporting within 5 s of target acquisition. It can also measure the redshifts of GRBs with Fe line emission or other spectral features. The XRT operates in an auto-exposure mode, adjusting the CCD readout mode automatically to optimize the science return for each frame as the source intensity fades. The XRT will measure spectra and lightcurves of the GRB afterglow beginning about a minute after the burst and will follow each burst for days or weeks.PUBLICATION ABSTRACT
Background: Although several diagnostic methods are available for the surveillance of patients at risk of human cytomegalovirus (CMV) infection and disease, little data is available on their ...comparative performances in the diagnostic setting.
Objectives: To compare different assays for CMV detection, especially assays based on (quantitative) DNA and mRNA detection.
Study design: Eight allogeneic bone marrow and stem cell transplant recipients at high risk for developing CMV disease (donor CMV-negative, recipient positive) were regularly tested for 7–20 weeks post-transplant by spin-amplification rapid culture from urine (viruria), antigenemia (pp65 assay), pp67 mRNA in whole blood (NASBA), and CMV DNA both qualitatively (in-house PCR, whole blood) and quantitatively (in-house PCR, plasma; Cobas Amplicor™ CMV Monitor Test, plasma and whole blood; Hybrid Capture™, whole blood).
Results: Four patients (50%) suffered CMV reactivation during follow-up. Out of 104 sample dates, 41 (39.4%) yielded a positive CMV result in at least one assay. Out of the 28 samples tested by all assays, the highest percentage of positive results was obtained with the in-house quantitative PCR (60.7%), followed by the Hybrid Capture™ system (39.3%), the Cobas Amplicor™ CMV Monitor Test, plasma version (35.7%), the Cobas Amplicor™ CMV Monitor Test, whole blood version (32.1%), in-house qualitative PCR (28.6%), and the mRNA assay (21.4%). Viruria was positive in one sample and pp65 antigenemia was found in two samples.
Conclusions: Despite a considerable incidence of CMV reactivations, pre-emptive anti-CMV chemotherapy prevented the development of CMV disease with the exception of one case. The molecular assays had superior sensitivity to conventional ones. The antigenemia assay proved unsuitable for the surveillance of hematological transplant patients. However, none of the tests recognized all timepoints with CMV reactivation. Further comparative studies are needed to determine their respective diagnostic values.
Hypothetical axionlike particles with a two-photon interaction would be produced in the sun by the Primakoff process. In a laboratory magnetic field ("axion helioscope"), they would be transformed ...into x-rays with energies of a few keV. Using a decommissioned Large Hadron Collider test magnet, the CERN Axion Solar Telescope ran for about 6 months during 2003. The first results from the analysis of these data are presented here. No signal above background was observed, implying an upper limit to the axion-photon coupling g(agamma)<1.16x10(-10) GeV-1 at 95% C.L. for m(a) less, similar 0.02 eV. This limit, assumption-free, is comparable to the limit from stellar energy-loss arguments and considerably more restrictive than any previous experiment over a broad range of axion masses.
The spin magnetic moment of a single proton in a cryogenic Penning trap was coupled to the particle's axial motion with a superimposed magnetic bottle. Jumps in the oscillation frequency indicate ...spin flips and were identified using a Bayesian analysis.
The X-ray Telescope (XRT) for the SWIFT mission, built by the international consortium from Pennsylvania State University (US), University of Leicester (UK) and Osservatorio Astronomico di Brera ...(Italy), is already installed on the SWIFT spacecraft. The XRT has two key functions on SWIFT; to determine locations of GRBs to better than 5 arc seconds within 100 seconds of initial detection of a burst and to measure spectra and light curves of the X-ray afterglow over around four orders of magnitude of decay in the afterglow intensity. This paper summarises the XRT performance, operating modes and sensitivity for the detection of prompt and extended X-ray afterglows from gamma-ray bursts. The performance characteristics have been determined from data taken during the ground calibration campaign at MPE's Panter facility in September 2002.
Upon starvation or overcrowding, Caenorhabditis elegans interrupts its reproductive cycle and forms a specialised larva called dauer (enduring). This process is regulated by TGF-beta and ...insulin-signalling pathways and is connected with the control of life span through the insulin pathway components DAF-2 and DAF-16. We found that replacing cholesterol with its methylated metabolite lophenol induced worms to form dauer larvae in the presence of food and low population density. Our data indicate that methylated sterols do not actively induce the dauer formation but rather that the reproductive growth requires a cholesterol-derived hormone that cannot be produced from methylated sterols. Using the effect of lophenol on growth, we have partially purified activity, named gamravali, which promotes the reproduction. In addition, the effect of lophenol allowed us to determine the role of sterols during dauer larva formation and longevity. In the absence of gamravali, the nuclear hormone receptor DAF-12 is activated and thereby initiates the dauer formation program. Active DAF-12 triggers in neurons the nuclear import of DAF-16, a forkhead domain transcription factor that contributes to dauer differentiation. This hormonal control of DAF-16 activation is, however, independent of insulin signalling and has no influence on life span.
Abstract
The CAST-CAPP axion haloscope, operating at CERN inside the CAST dipole magnet, has searched for axions in the 19.74
μ
eV to 22.47
μ
eV mass range. The detection concept follows the ...Sikivie haloscope principle, where Dark Matter axions convert into photons within a resonator immersed in a magnetic field. The CAST-CAPP resonator is an array of four individual rectangular cavities inserted in a strong dipole magnet, phase-matched to maximize the detection sensitivity. Here we report on the data acquired for 4124 h from 2019 to 2021. Each cavity is equipped with a fast frequency tuning mechanism of 10 MHz/ min between 4.774 GHz and 5.434 GHz. In the present work, we exclude axion-photon couplings for virialized galactic axions down to
g
a
γ
γ
= 8 × 10
−14
GeV
−1
at the 90% confidence level. The here implemented phase-matching technique also allows for future large-scale upgrades.
A
bstract
We present results of the Relic Axion Dark-Matter Exploratory Setup (RADES), a detector which is part of the CERN Axion Solar Telescope (CAST), searching for axion dark matter in the 34.67
...μ
eV mass range. A radio frequency cavity consisting of 5 sub-cavities coupled by inductive irises took physics data inside the CAST dipole magnet for the first time using this filter-like haloscope geometry. An exclusion limit with a 95% credibility level on the axion-photon coupling constant of g
aγ
≳ 4 × 10
−
13
GeV
−
1
over a mass range of 34
.
6738
μ
eV
< m
a
<
34
.
6771
μ
eV is set. This constitutes a significant improvement over the current strongest limit set by CAST at this mass and is at the same time one of the most sensitive direct searches for an axion dark matter candidate above the mass of 25
μ
eV. The results also demonstrate the feasibility of exploring a wider mass range around the value probed by CAST-RADES in this work using similar coherent resonant cavities.
Summary
Background The incidence of syphilis is increasing in many parts of the world including a re‐emergence in Western Europe and North America. Depending on the disease stage, direct detection ...of Treponema pallidum in mucocutaneous lesions of syphilis may be difficult and histopathological findings are not always straightforward. Thus, the correct histological diagnosis may be challenging.
Objectives Comparatively to evaluate the evidence for infection with T. pallidum by immunohistochemistry (IHC), polymerase chain reaction (PCR) and focus‐floating microscopy (FFM).
Methods A series of 86 paraffin‐embedded skin biopsy samples from patients with primary, secondary or tertiary syphilis was assessed for detection of T. pallidum by IHC and FFM; 45 specimens were also investigated by a T. pallidum‐specific PCR analysis. Histopathological reaction patterns and number and distribution of treponemes were studied, and all data were re‐evaluated by clinicopathological correlation.
Results Using a polyclonal antibody directed against T. pallidum, we detected the presence of T. pallidum by IHC in 42/86 (49%) samples 6/9 (67%) primary, 34/62 (55%) secondary and 2/15 (13%) tertiary syphilis. T. pallidum‐specific DNA was detected in 31/45 (69%) specimens 4/4 (100%) primary, 26/34 (76%) secondary and 1/7 (14%) tertiary syphilis. In comparison, FFM analysis resulted in an overall detection rate of 82/86 (95%) 9/9 (100%) primary, 60/62 (97%) secondary and 13/15 (87%) tertiary syphilis. Significant differences were observed concerning amount and distribution of organisms (epitheliotropic vs. endotheliotropic) in correlation to the three disease stages and to histopathological reaction patterns.
Conclusions FFM is a highly sensitive and specific method to detect T. pallidum in tissue from mucocutaneous syphilis lesions. Our results indicate that a combination of PCR and FFM, as the most sensitive approach, could provide an additional benefit for the histopathological diagnosis of (late) secondary and tertiary syphilis and may be helpful in cases where serological testing of T. pallidum antibodies has failed, but the clinical suspicion for syphilis remains.
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