1,469 research outputs found
An attempt to identify the extended synchrotron structure associated with the micro-quasar GRS 1915+105
The energy ejected from the galaxy micro-quasar GRS1915+105 in the form of
jets is expected to lead to formation of an extended double lobe/hot-spot
structure with the energy content comparable to an average supernova remnant.
We used the Effelsberg 100m telescope at 10.45 GHz in attempt to identify such
structures. For this distant galactic plane source any definite identification
was not possible due to high confusion by numerous background sources, however,
a few suspect structures were pointed out.Comment: LaTeX uses a new 2001 A&A macro, 4 pages, 2 figures, A&A accepte
Temporal Variations of Strength and Location of the South Atlantic Anomaly as Measured by RXTE
The evolution of the particle background at an altitude of ~540 km during the
time interval between 1996 and 2007 is studied using the particle monitor of
the High Energy X-ray Timing Experiment on board NASA's Rossi X-ray Timing
Explorer. A special emphasis of this study is the location and strength of the
South Atlantic Anomaly (SAA). The size and strength of the SAA are
anti-correlated with the the 10.7 cm radio flux of the Sun, which leads the SAA
strength by ~1 year reflecting variations in solar heating of the upper
atmosphere. The location of the SAA is also found to drift westwards with an
average drift rate of about 0.3 deg/yr following the drift of the geomagnetic
field configuration. Superimposed to this drift rate are irregularities, where
the SAA suddenly moves eastwards and where furthermore the speed of the drift
changes. The most prominent of these irregularities is found in the second
quarter of 2003 and another event took place in 1999. We suggest that these
events are previously unrecognized manifestations of the geomagnetic jerks of
the Earth's magnetic field.Comment: 21 pages, 11 figures, accepted for publication in Earth and Planetary
Science Letter
Radio spectral properties and the magnetic field of the SNR S147
(Abridged) S147 is a large faint shell-type supernova remnant (SNR). Its
remarkable spectral break at cm-wavelengths is an important physical property
to characterize the SNR evolution. However, the spectral break is based on
radio observations with limited precision. We made new radio continuum and
polarization observations of S147 at 11cm and at 6cm with the Effelsberg 100-m
telescope and the Urumqi 25-m telescope, respectively. These new data were
combined with published lower frequency data from the Effelsberg 100-m
telescope and very high frequency data from WMAP to investigate the spectral
turnover and polarization properties of S147. S147 consists of numerous
filaments embedded in diffuse emission. We found that the integrated flux
densities of S147 are 34.8+/-4.0 Jy at 11cm and 15.4+/-3.0Jy at 6cm. These new
measurements confirm the known spectral turnover at ~1.5GHz, which can be
entirely attributed to the diffuse emission component. The spectral index above
the turnover is -1.35+/-0.20. The filamentary emission component has a constant
spectral index over the entire wavelength range up to 40.7GHz of -0.35+/-0.15.
The weak polarized emission of S147 is at the same level as the ambient diffuse
Galactic polarization. The rotation measure of the eastern filamentary shell is
about -70 rad/m2. The filamentary and diffuse emission components of S147 have
different physical properties, which make S147 outstanding among shell type
SNRs.The weak polarization of S147 at 11cm and at 6cm can be attributed to a
section of the S147 shell showing a tangential magnetic field direction.Comment: 11 pages, 17 figures, accepted for publication in Astronomy &
Astrophysics, the resolution of some figures have been reduced. For high
resolution version, see
ftp://ftp.mpifr-bonn.mpg.de/outgoing/p098wre/xiao-etal.pdf,revised following
the language edito
Innovative methods in European road freight transport statistics: A pilot study
By using innovative methods, such as the automated transfer of corporate electronic data to National Statistical Institutions, official transport data can be significantly improved in terms of reliability, costs and the burden on respondents. In this paper, we show that the automated compilation of statistical reports is possible and feasible. Based on previous findings, a new method and tool were developed in cooperation with two business partners from the logistics sector in Austria. The results show that the prototype could successfully be implemented at the partner companies. Improved data quality can lead to more reliable analyses in various fields. Compared to actual volumes of investments into transport, the costs of transport statistics are limited. By using the new and innovative data collection techniques, these costs can even be reduced in the long run; at the same time, the risk of bad investments and wrong decisions caused by analyses relying on poor data quality can be reduced. This results in a substantial value for business, research, the economy and the society
Evidence for different accretion regimes in GRO J1008-57
We present a comprehensive spectral analysis of the BeXRB GRO J1008-57 over a
luminosity range of three orders of magnitude using NuSTAR, Suzaku and RXTE
data. We find significant evolution of the spectral parameters with luminosity.
In particular the photon index hardens with increasing luminosity at
intermediate luminosities between erg s. This
evolution is stable and repeatedly observed over different outbursts. However,
at the extreme ends of the observed luminosity range, we find that the
correlation breaks down, with a significance level of at least . We
conclude that these changes indicate transitions to different accretion
regimes, which are characterized by different deceleration processes, such as
Coulomb or radiation breaking. We compare our observed luminosity levels of
these transitions to theoretical predications and discuss the variation of
those theoretical luminosity values with fundamental neutron star parameters.
Finally, we present detailed spectroscopy of the unique "triple peaked"
outburst in 2014/15 which does not fit in the general parameter evolution with
luminosity. The pulse profile on the other hand is consistent with what is
expected at this luminosity level, arguing against a change in accretion
geometry. In summary, GRO J1008-57 is an ideal target to study different
accretion regimes due to the well constrained evolution of its broad-band
spectral continuum over several orders of magnitude in luminosity.Comment: 13 pages, 7 figures, 3 tables. Accepted for publication in A&
Radio properties of the low surface brightness SNR G65.2+5.7
Many physical properties of this SNR such as spectrum and polarization can
only be investigated by radio observations. The 11 cm and 6\
cm continuum and polarization observations of SNR G65.2+5.7 were made with the
Effelsberg 100-m and the Urumqi 25-m telescopes, respectively, to investigate
the integrated spectrum, the spectral index distribution, and the magnetic
field properties. 21 cm archival data from the Effelsberg 100-m
telescope have been also used. The integrated flux densities of G65.2+5.7 at
cm and cm are Jy and 16.81.8 Jy,
respectively. The power-law spectrum () is well fitted by
from 83 MHz to 4.8 GHz. Spatial spectral variations are
small. Along the northern shell strong depolarizion is observed at both
wavelengths. The southern filamentary shell of SNR G65.2+5.7 is polarized up to
54% at cm. There is significant depolarization at cm
and confusion with diffuse polarized Galactic emission. Using equipartition
principle, we estimated the magnetic field strength for the southern
filamentary shell about 20 G (filling factor 1) to 50 G (filling
factor 0.1). A faint HI shell may be associated with the SNR. Despite its
unusual strong X-ray and optical emission and its very low surface brightness,
the radio properties of SNR G65.2+5.7 are found to be typical for evolved shell
type SNRs. SNR G65.2+5.7 may be expanding in a preblown cavity as indicated by
a deficit of HI gas and a possible HI-shell.Comment: 11pages,13figures,accepted by A&A, revised following the language
editor. For high resolution version, please go to
ftp://ftp.mpifr-bonn.mpg.de/outgoing/p098wre/xiao-etal-g65.pd
Zystoskopie bei einem Rind mit Urachus persistens-Ruptur
Die Arbeit beschreibt die klinischen, sonographischen und zystoskopischen Befunde sowie die Therapie bei einem 2-jährigen, 7 Monate trächtigen Braunviehrind mit Ruptur des Urachus persistens. Das Leitsymptom war ein birnförmiges Abdomen bei stark gestörtem Allgemeinbefinden. Die Blutuntersuchung ergab eine hochgradige Azotämie. Bei der Ultraschalluntersuchung wurde ein Aszites festgestellt, welcher aufgrund der massiv erhöhten Kreatininkonzentration im Punktat als Uroperitoneum klassiert wurde. Bei der Zystoskopie konnte das Endoskop über die Harnblase in einen persistierenden Urachus eingeführt werden. Aufgrund sämtlicher Befunde wurde die Diagnose Uroperitoneum infolge Ruptur eines Urachus persistens gestellt. Als Therapie wurde eine Laparotomie in der linken Flanke mit doppelter Ligation des Urachus durchgeführt. Innerhalb von wenigen Tagen normalisierte sich der Zustand des Rindes. Es hat inzwischen normal gekalbt und erfreut sich bester Gesundheit
This case report describes the clinical, ultrasonographic and cystoscopic findings and treatment in a two-year-old Swiss Braunvieh heifer with rupture of a patent urachus. The lead signs in the seven-month-pregnant heifer were markedly abnormal general condition and demeanour and a pear-shaped abdomen. The heifer had severe azotaemia, and abdominal ultrasonography revealed ascites, which was diagnosed as uroperitoneum based on an elevated creatinine level in the fluid. A patent urachus was identified during cystoscopy; the endoscope could be advanced beyond the apex of the urinary bladder into the urachus. Based on all the findings, a diagnosis of uroperitoneum attributable to rupture of a patent urachus was made. The urachus was ligated twice via a left-flank laparotomy. The general condition normalised within a few days of surgery, and the patient calved normally and was in good health at follow-up evaluation
Standing osteosynthesis of an accessory carpal bone fracture in a Warmblood mare with a 6‐hole 3.5 talonavicular fusion plate and 3.5‐mm screws
A 9-year-old Warmblood, high-level showjumping mare sustained an acute, closed, vertical, comminuted fracture of the left accessory carpal bone (ACB) during a fall. The fracture was repaired under standing sedation and local anaesthesia, using a 6-hole APTUS® 3.5 TFP and 5 × 3.5-mm self-tapping TriLock© screws. The mare recovered from surgery without complications. Upon follow-up examination 9 months post-operatively the mare was sound in all gaits and back to full athletic activity. The ACB fracture had completely healed. The displaced dorsoproximal fracture fragment was in a stationary position and there was evidence of mild nonprogressive osteoarthritis of the antebrachiocarpal joint
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