36 research outputs found

    FIRST NuSTAR OBSERVATIONS of MRK 501 WITHIN A RADIO to TeV MULTI-INSTRUMENT CAMPAIGN

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    © 2015. The American Astronomical Society. All rights reserved.. We report on simultaneous broadband observations of the TeV-emitting blazar Markarian 501 between 2013 April 1 and August 10, including the first detailed characterization of the synchrotron peak with Swift and NuSTAR. During the campaign, the nearby BL Lac object was observed in both a quiescent and an elevated state. The broadband campaign includes observations with NuSTAR, MAGIC, VERITAS, the Fermi Large Area Telescope, Swift X-ray Telescope and UV Optical Telescope, various ground-based optical instruments, including the GASP-WEBT program, as well as radio observations by OVRO, MetsÀhovi, and the F-Gamma consortium. Some of the MAGIC observations were affected by a sand layer from the Saharan desert, and had to be corrected using event-by-event corrections derived with a Light Detection and Ranging (LIDAR) facility. This is the first time that LIDAR information is used to produce a physics result with Cherenkov Telescope data taken during adverse atmospheric conditions, and hence sets a precedent for the current and future ground-based gamma-ray instruments. The NuSTAR instrument provides unprecedented sensitivity in hard X-rays, showing the source to display a spectral energy distribution (SED) between 3 and 79 keV consistent with a log-parabolic spectrum and hard X-ray variability on hour timescales. None (of the four extended NuSTAR observations) show evidence of the onset of inverse-Compton emission at hard X-ray energies. We apply a single-zone equilibrium synchrotron self-Compton (SSC) model to five simultaneous broadband SEDs. We find that the SSC model can reproduce the observed broadband states through a decrease in the magnetic field strength coinciding with an increase in the luminosity and hardness of the relativistic leptons responsible for the high-energy emission

    FIRST NuSTAR

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    Remarks on two European wigeon x Northern pintail hybrids

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    Volume: 86Start Page: 8End Page: 1

    Molecular differentiation at nuclear loci in French host races of the European corn borer (Ostrinia nubilalis).

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    French populations of the European corn borer consist of two sympatric and genetically differentiated host races. As such, they are well suited to study processes that could be involved in sympatric speciation, but the initial conditions of host-race divergence need to be elucidated. Gene genealogies can provide insight into the processes involved in speciation. We used DNA sequences of four nuclear genes to (1) document the genetic structure of the two French host races previously delineated with allozyme markers, (2) find genes directly or indirectly involved in reproductive isolation between host races, and (3) estimate the time since divergence of the two taxa and see whether this estimate is compatible with this divergence being the result of a host shift onto maize after its introduction into Europe ∌500 years ago. Gene genealogies revealed extensive shared polymorphism, but confirmed the previously observed genetic differentiation between the two host races. Significant departures from the predictions of neutral molecular evolution models were detected at three loci but were apparently unrelated to reproductive isolation between host races. Estimates of time since divergence between French host races varied from ∌75,000 to ∌150,000 years, suggesting that the two taxa diverged recently but probably long before the introduction of maize into Europe

    Trabecular pattern in intraoral radiographs as a sign of osteoporosis : the OSTEODENT study

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    Objectives: The aim of this study was to investigate if the trabecular pattern in intraoral radiographs, assessed by five observers, could serve as an indicator of osteoporosis. Methods: Six hundred and seventy one women (45 - 70 yrs) from four European centers were included in the study and examined with intraoral radiographs in the right upper and lower premolar region. The patients also underwent examinations with central dual energy X-ray absorptiometry (DXA) of the hip and lumbar spine. Five observers assessed the trabecular pattern in the intraoral radiographs into one of three classes: dense, heterogeneous or sparse trabecular pattern. The assessments were made with the aid of reference images and the observers underwent a calibration procedure before starting their assessments. The classifications were compared with the true diagnosis of osteoporosis measured using DXA. Results: The sensitivity and specificity for five observers’ assessments of the intraoral radiographs with sparse trabecular pattern as indicative of osteoporosis at either hip or spine are given in the table below. The values are calculated for patients diagnosed as having osteoporosis at any of the examined sites. Upper jaw Lower jaw Observer Sensitivity Specificity Sensitivity Specificity 1 22.2 90.2 13.2 94.5 2 22.6 94.8 15.8 94.2 3 26.5 91.6 28.1 86.7 4 36.3 87.4 30.2 82.4 5 35.3 93.7 39.1 95.6 If the cut-off included either “heterogeneous” or “sparse” trabeculation then a higher sensitivity was achieved (90.6 – 73.7) but a lower specificity (49.4 – 26.2). Conclusion: Assessment of sparse trabecular pattern on intraoral radiographs offered a combination of low sensitivity but high specificity for osteoporosis diagnosis. If it is assumed that high specificity is preferred for osteoporosis assessment by dentists, then this method may have potential for clinical use, although inter-observer variability may be a problem. This work was supported by a research and technological development project grant from the European Commission FP5 'Quality of Life and Management of Living Resources' (QLK6-2002-02243)

    Firstnustarobservations of mrk 501 within a radio to tev multi-instrument campaign

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    We report on simultaneous broadband observations of the TeV-emitting blazar Markarian 501 between 2013 April 1 and August 10, including the first detailed characterization of the synchrotron peak with Swift and NuSTAR. During the campaign, the nearby BL Lac object was observed in both a quiescent and an elevated state. The broadband campaign includes observations with NuSTAR, MAGIC, VERITAS, the Fermi Large Area Telescope, Swift X-ray Telescope and UV Optical Telescope, various ground-based optical instruments, including the GASP-WEBT program, as well as radio observations by OVRO, Metsahovi, and the F-Gamma consortium. Some of the MAGIC observations were affected by a sand layer from the Saharan desert, and had to be corrected using event-by-event corrections derived with a Light Detection and Ranging (LIDAR) facility. This is the first time that LIDAR information is used to produce a physics result with Cherenkov Telescope data taken during adverse atmospheric conditions, and hence sets a precedent for the current and future ground-based gamma-ray instruments. The NuSTAR instrument provides unprecedented sensitivity in hard X-rays, showing the source to display a spectral energy distribution (SED) between 3 and 79 keV consistent with a log-parabolic spectrum and hard X-ray variability on hour timescales. None (of the four extended NuSTAR observations) show evidence of the onset of inverse-Compton emission at hard X-ray energies. We apply a single-zone equilibrium synchrotron self-Compton (SSC) model to five simultaneous broadband SEDs. We find that the SSC model can reproduce the observed broadband states through a decrease in the magnetic field strength coinciding with an increase in the luminosity and hardness of the relativistic leptons responsible for the high-energy emission
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