Context. Observations of very high-energy gamma -rays from blazars provide information about acceleration mechanisms occurring in their innermost regions. Studies of variability in these objects lead ...to a better understanding of the mechanisms in play. Aims. To investigate the spectral and temporal variability of VHE (>100 GeV) gamma -rays of the well-known high-frequency-peaked BLLac object PKS2155-304 with the HESS imaging atmospheric Cherenkov telescopes over a wide range of flux states. Methods. Data collected from 2005 to 2007 were analyzed. Spectra were derived on time scales ranging from 3 years to 4 min. Light curve variability was studied through doubling timescales and structure functions and compared with red noise process simulations. Results. The source was found to be in a low state from 2005 to 2007, except for a set of exceptional flares that occurred in July 2006. The quiescent state of the source is characterized by an associated mean flux level of (4.32 plus or minus 0.09 sub(stat) plus or minus 0.86 sub(syst)) x 10 super(-11) cm super(-2) s super(-1) above 200 GeV, or approximately 15% of the Crab Nebula, and a power-law photon index of Gamma = 3.53 plus or minus 0.06 sub(stat) plus or minus 0.10 sub(syst). During the flares of July 2006, doubling timescales of ~2 min are found. The spectral index variation is examined over two orders of magnitude in flux, yielding different behavior at low and high fluxes, which is a new phenomenon in VHE gamma -ray emitting blazars. The variability amplitude characterized by the fractional rms F sub(var) is strongly energy-dependent and is alpha E super(0.10 plus or minus 0.01). The light curve rms correlates with the flux. This is the signature of a multiplicative process that can be accounted for as a red noise with a Fourier index of ~2. Conclusions. This unique data set shows evidence of a low-level gamma -ray emission state from PKS2155-304 that possibly has a different origin than the outbursts. The discovery of the light curve lognormal behavior might be an indicator of the origin of aperiodic variability in blazars.
Aim.
We aim for an understanding of the morphological and spectral properties of the supernova remnant RCW 86 and for insights into the production mechanism leading to the RCW 86 very high-energy
γ
...-ray emission.
Methods.
We analyzed High Energy Spectroscopic System (H.E.S.S.) data that had increased sensitivity compared to the observations presented in the RCW 86 H.E.S.S. discovery publication. Studies of the morphological correlation between the 0.5–1 keV X-ray band, the 2–5 keV X-ray band, radio, and
γ
-ray emissions have been performed as well as broadband modeling of the spectral energy distribution with two different emission models.
Results.
We present the first conclusive evidence that the TeV
γ
-ray emission region is shell-like based on our morphological studies. The comparison with 2–5 keV X-ray data reveals a correlation with the 0.4–50 TeV
γ
-ray emission. The spectrum of RCW 86 is best described by a power law with an exponential cutoff at
E
cut
= (3.5 ± 1.2
stat
) TeV and a spectral index of Γ ≈ 1.6 ± 0.2. A static leptonic one-zone model adequately describes the measured spectral energy distribution of RCW 86, with the resultant total kinetic energy of the electrons above 1 GeV being equivalent to ~0.1% of the initial kinetic energy of a Type Ia supernova explosion (10
51
erg). When using a hadronic model, a magnetic field of
B
≈ 100
μ
G is needed to represent the measured data. Although this is comparable to formerly published estimates, a standard E
−2
spectrum for the proton distribution cannot describe the
γ
-ray data. Instead, a spectral index of Γ
p
≈ 1.7 would be required, which implies that ∼7 × 10
49
/
n
cm
−3
has been transferred into high-energy protons with the effective density
n
cm
−3
=
n
/1 cm
−3
. This is about 10% of the kinetic energy of a typical Type Ia supernova under the assumption of a density of 1 cm
−3
.
One God – One Cult – One Nation Reinhard G. Kratz, Hermann Spieckermann / Björn Corzilius, Tanja Pilger / Reinhard G. Kratz, Hermann Spieckermann
2010
eBook
The series Beihefte zur Zeitschrift für die alttestamentliche Wissenschaft (BZAW) covers all areas of research into the Old Testament, focusing on the Hebrew Bible, its early and later forms in ...Ancient Judaism, as well as its branching into many neighboring cultures of the Ancient Near East and the Greco-Roman world. BZAW welcomes submissions that make an original and significant contribution to the field; demonstrate sophisticated engagement with the relevant secondary literature; and are written in readable, logical, and engaging prose.
Cinnamate 4-hydroxylase CA4H; trans-cinnamate, NADPH:oxygen oxidoreductase (4-hydroxylating), EC 1.14.13.11 is a cytochrome P450 that catalyzes the first oxygenation step of the general ...phenylpropanoid metabolism in higher plants. The compounds formed are essential for lignification and defense against predators and pathogens. We recently reported the purification of this enzyme from Mn2+-induced Jerusalem artichoke (Helianthus tuberosus L.) tuber tissues. Highly selective polyclonal antibodies raised against the purified protein were used to screen a lambda gt11 cDNA expression library from wound-induced Jerusalem artichoke, allowing isolation of a 1130-base-pair insert. Typical P450 domains were identified in this incomplete sequence, which was used as a probe for the isolation of a 1.7-kilobase clone in a lambda gt10 library. A full-length open reading frame of 1515 base pairs, encoding a P450 protein of 505 residues (Mr = 57,927), was sequenced. The N terminus, essentially composed of hydrophobic residues, matches perfectly the microsequenced N terminus of the purified protein. The calculated pI is 9.78, in agreement with the chromatographic behavior and two-dimensional electrophoretic analysis of CA4H. Synthesis of the corresponding mRNA is induced in wounded plant tissues, in correlation with CA4H enzymatic activity. This P450 protein exhibits the most similarity (28% amino acid identity) with avocado CYP71, but also good similarity with CYP17 and CYP21, or with CYP1 and CYP2 families. According to current criteria, it qualifies as a member of a new P450 family.
Aims. Following the detection of the fast radio burst FRB150418 by the SUPERB project at the Parkes radio telescope, we aim to search for very-high energy gamma-ray afterglow emission. Methods. ...Follow-up observations in the very-high energy gamma-ray domain were obtained with the H.E.S.S. imaging atmospheric Cherenkov telescope system within 14.5 h of the radio burst. Results. The obtained 1.4 h of gamma-ray observations are presented and discussed. At the 99% C.L. we obtained an integral upper limit on the gamma-ray flux of Phi sub( gamma )(E> 350 GeV) < 1.33 x 10 super(-8) m super(-2) s super(-1). Differential flux upper limits as function of the photon energy were derived and used to constrain the intrinsic high-energy afterglow emission of FRB 150418. Conclusions. No hints for high-energy afterglow emission of FRB 150418 were found. Taking absorption on the extragalactic background light into account and assuming a distance of z= 0.492 based on radio and optical counterpart studies and consistent with the FRB dispersion, we constrain the gamma-ray luminosity at 1 TeV to L< 5.1 x 10 super(47) erg/s at 99% C.L.
Trocar insertion during laparoscopic preperitoneal hernia repair (TEP) can be troublesome because the space into which the trocars are inserted is smaller than that available for transabdominal ...approaches. Insertion of the trocars directly into the balloon used to dissect the preperitoneal space can facilitate this process. The insertion of a 5-mm trocar into the balloon does not usually result in balloon deflation, and a second trocar can be placed into the balloon as well. Removing the balloon, despite the trocars inside it, is straightforward, allowing the placement of a cannula at the balloon insertion site and initiation of the hernia repair.
Using the HEGRA system of imaging atmospheric Cherenkov telescopes, the Andromeda galaxy (M 31) was surveyed for TeV gamma ray emission. Given the large field of view of the HEGRA telescopes, three ...pointings were sufficient to cover all of M 31, including also M 32 and NGC 205. No indications for point sources of TeV gamma rays were found. Upper limits are given at a level of a few percent of the Crab flux. A specific search for monoenergetic gamma-ray lines from annihilation of supersymmetric dark matter particles accumulating near the center of M 31 resulted in flux limits in the 10-13 cm-2 s-1 range, well above the predicted MSSM flux levels except for models with pronounced dark-matter spikes or strongly enhanced annihilation rates.
To evaluate a new wavelet-based computer-assisted detection (CAD) system for detecting and enhancing microcalcifications.
A total of 280 mammograms acquired by full-field digital mammography ...(Senographe 2000D; G.E. Medical Systems Milwaukee, Wisc., USA) were analyzed with and without a new wavelet-based CAD system for detecting and enhancing microcalcifications. The mammograms comprised roughly equal numbers of cases from each of the BIRADS (Breast Imaging, Reporting and Data System, according to the American College of Roentgenology) categories 1-5. Histologic confirmation was available for all of the 180 cases assigned BIRADS categories 3-5. Four readers interpreted all 280 images for suspicious microcalcifications using a scale of 1-5. The readers alternately assessed 5 images with and 5 without CAD. In a second reading immediately following the first, the readers had to reassess the 280 mammograms. The images that had already been interpreted without CAD were now presented with CAD and vice versa. The images were interpreted as soft copies on a diagnostic mammography workstation (Image Diagnost GmbH, Neufahrn/Munich, Germany). All images interpreted with CAD were presented with enhancement of microcalcifications by wavelet algorithms and prompting of microcalcifications. ROC (receiver operating characteristic) analyses were performed, and image interpretation time with and without CAD was measured.
The overall time for interpretation required by all 4 readers together was 483 min with CAD compared to 580 min without CAD. ROC analysis revealed no significant advantage of CAD for the individual readers. Readers 3 (0.811/0.817) and 4 (0.799/0.843) had a slightly improved AUC (area under the curve) with CAD. Readers 1 and 2 had a slightly lower AUC with CAD (0.832 versus 0.861 and 0.818 versus 0.849).
The CAD system significantly (P<0.05, t test) speeded up image interpretation with respect to the identification of microcalcifications, while the diagnostic quality remained almost identical under the study conditions.
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