4,636 research outputs found

    On the Statistical Relationship between CME Speed and Soft X-ray Flux and Fluence of the Associated Flare

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    Both observation and theory reveal a close relationship between the kinematics of coronal mass ejections (CMEs) and the thermal energy release traced by the related soft X-ray (SXR) emission. The major problem of empirical studies of this relationship is the distortion of the CME speed by the projection effect in the coronagraphic measurements. We present a re-assessment of the statistical relationship between CME velocities and SXR parameters, using the SOHO/LASCO catalog and GOES whole Sun observations during the period 1996 to 2008. 49 events were identified where CMEs originated near the limb, at central meridian distances between 70^\circ and 85^\circ, and had a reliably identified SXR burst, the parameters of which - peak flux and fluence - could be determined with some confidence. We find similar correlations between the logarithms of CME speed and of SXR peak flux and fluence as several earlier studies, with correlation coefficients of 0.48 and 0.58, respectively. Correlations are slightly improved over an unrestricted CME sample when only limb events are used. However, a broad scatter persists. We derive the parameters of the CME-SXR relationship and use them to predict ICME arrival times at Earth. We show that the CME speed inferred from SXR fluence measurements tends to perform better than SoHO/LASCO measurements in the prediction of ICME arrival times near 1 AU. The estimation of the CME speed from SXR observations can therefore make a valuable contribution to space weather predictions.Comment: Solar Physics, in pres

    Commentary on "the state of the monetarist debate"

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    Monetary policy ; Fiscal policy

    Count Zeppelin in Alsace in 1870 (Illustrated).

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    Creating Experiences: On the Front Lines of Customer Service

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    Giving excellent customer service is important to our businesses. This presentation will cover what rural customers want, how to keep existing customers, how to build connections with the ‘top dogs’, and create a referral network with mavens

    POSTURAL BALANCE AND BIOMECHANICAL PROBLEMS FOR THE KNEE

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    The increased emphasis of jogging and running and for the special few, the marathon, has increased with exploding emphasis in the past few year. If any person wished to follow the "circuit," a 10K race (6 miles), 5 miler:, or any other combination of distances, they could take part in competition in any section of the country on a daily and weekly basis providing transportation and funds were available. By and large the runner/jogger pretty much confines their activity to the local scene, running at the track, on the streets or hike and bike trails such as are found in Austin

    Exploring the capabilities of the Anti-Coincidence Shield of the INTEGRAL spectrometer to study solar flares

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    INTEGRAL is a hard X-ray/gamma-ray observatory for astrophysics (ESA) covering photon energies from 15 keV to 10 MeV. It was launched in 2002 and since then the BGO detectors of the Anti-Coincidence shield (ACS) of the SPI spectrometer have detected many hard X-ray (HXR) bursts from the Sun, producing lightcurves at photon energies above ~ 100 keV. The spacecraft has a highly elliptical orbit, providing a long uninterrupted observing time (about 90% of the orbital period) with nearly constant background due to the reduction of the crossing time of the Earth's radiation belts. However, due to technical constraints, INTEGRAL cannot point to the Sun and high-energy solar photons are always detected in non-standard observation conditions. To make the data useful for solar studies, we have undertaken a major effort to specify the observing conditions through Monte-Carlo simulations of the response of ACS for several selected flares. We check the performance of the model employed for the Monte-Carlo simulations using RHESSI observations for the same sample of solar flares. We conclude that, despite the fact that INTEGRAL was not designed to perform solar observations, ACS is a useful instrument in solar flare research. In particular, its relatively large effective area allows the determination of good-quality HXR/gamma-ray lightcurves for X- and M-class solar flares and, in some cases, probably also for C-class flares.Comment: 18 pages, 6 figures; Solar Physics 201

    Die blande Struma

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    The past, the present, and the future of future-oriented mental time travel: Editors' introduction

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    This introductory chapter reviews research on future-oriented mental time travel to date (the past), provides an overview of the contents of the book (the present), and enumerates some possible research directions suggested by the latter (the future)
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