H.E.S.S. observations of the Large Magellanic Cloud

The Large Magellanic Cloud (LMC) is a satellite galaxy of the Milky Way at a distance of approximately 48 kpc. Despite its distance it harbours several interesting targets for TeV gamma-ray observations. The composite supernova remnant N 157B/PSR J05367-6910 was discovered by H.E.S.S. being an emitter of very high energy (VHE) gamma-rays. It is the most distant pulsar wind nebula ever detected in VHE gamma-rays. Another very exciting target is SN 1987A, the remnant of the most recent supernova explosion that occurred in the neighbourhood of the Milky Way. Models for Cosmic Ray acceleration in this remnant predict gamma-ray emission at a level detectable by H.E.S.S. but this has not been detected so far. Fermi/LAT discovered diffuse high energy (HE) gamma-ray emission from the general direction of the massive star forming region 30 Doradus but no clear evidence for emission from either N 157B or SN 1987A has been published. The part of the LMC containing these objects has been observed regularly with the H.E.S.S. telescopes since 2003. With deep observations carried out in 2010 a very good exposure of this part of the sky has been obtained. The current status of the H.E.S.S. LMC observations is reported along with new results on N 157B and SN 1987A.Comment: 4 pages, 3 figures, proceedings of the 32nd Internatioal Cosmic Ray Conference, Beijing 201

Immunohistochemical Markers in the Assessment of Tumor Response

The examination of the possibility of using immunohistochemical and molecular (NCRT) and prognostic factors of the disease state. The study included 21 patients with locally advanced gastric cancer. All patients underwent the NCRT followed by gastrectomy D2. We analyzed the expression of HER2 / neu marker, Ki-67, p53, Cyklin D1, E-cadherin in biopsy (before therapy) and the operating material (after chemoradiotherapy and the treatment gap). We have found statistically significant decrease in the expression of Ki-67 markers and Cyklin D1, a trend towards to a decrease of p53 expression after the NCRT. The dynamics of expression of immunohistochemical markers examination is a promising approach in search for predictors of NCRT effectiveness for patients with locally advanced gastric cancer. Keywords: neoadjuvant chemoradiotherapy, immunohistochemical markers, molecular genetic markers, therapeutic pathomorphism, gastric cancer

Prevalence of Sorghum Ergot in Southeast Asia

Ergot is a serious endemic disease in most of the sorghum (Sorghum bicolor) producing countries of the wor ld, wi th most recent outbreaks being in central and South Amer ica (Reis et al . 1996). It is caused by the fungus Claviceps spp. Three species are predominant: C. africana is prevalent in southern and eastern Af r ica, South Amer ica, Southeast Asia, Aust ral ia, and India; C. sorghi in India and Southeast Asia; and C. sorghicola in Japa

Pulsar Wind Nebula candidates recently discovered by H.E.S.S

H.E.S.S. is currently the most sensitive instrument in the very-high-energy gamma-ray domain and has revealed many new sources along the Galactic Plane, a significant fraction of which seems to be associated with energetic pulsars. HESS J1825-137 and Vela X are considered to be the prototypes of such sources in which the large VHE nebula results from the whole history of the pulsar wind and the supernova remnant host, both evolving in a complex interstellar medium. These nebulae are seen to be offset from the pulsar position and, for HESS J1825-137, a spectral steepening at increasing distance from the pulsar has been measured. In this context, updated H.E.S.S. results on two previously published sources, namely HESS J1809-193 and HESS J1912+101, and preliminary results on the newly discovered HESS J1356-645, are presented. These extended VHE sources are thought to be associated with the energetic pulsars PSR J1809-1917, PSR J1913+1011 and PSR J1357-6429, respectively. Properties of each source in the VHE regime, together with those measured in the radio and X-ray domains, are discussed.Comment: 4 pages, 6 figures, Submitted to Proceedings of "4th Heidelberg International Symposium on High Energy Gamma-Ray Astronomy 2008

Expected performance of the ASTRI-SST-2M telescope prototype

ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) is an Italian flagship project pursued by INAF (Istituto Nazionale di Astrofisica) strictly linked to the development of the Cherenkov Telescope Array, CTA. Primary goal of the ASTRI program is the design and production of an end-to-end prototype of a Small Size Telescope for the CTA sub-array devoted to the highest gamma-ray energy region. The prototype, named ASTRI SST-2M, will be tested on field in Italy during 2014. This telescope will be the first Cherenkov telescope adopting the double reflection layout in a Schwarzschild-Couder configuration with a tessellated primary mirror and a monolithic secondary mirror. The collected light will be focused on a compact and light-weight camera based on silicon photo-multipliers covering a 9.6 deg full field of view. Detailed Monte Carlo simulations have been performed to estimate the performance of the planned telescope. The results regarding its energy threshold, sensitivity and angular resolution are shown and discussed.Comment: In Proceedings of the 33rd International Cosmic Ray Conference (ICRC2013), Rio de Janeiro (Brazil). All CTA contributions at arXiv:1307.223

Progress in Monte Carlo design and optimization of the Cherenkov Telescope Array

The Cherenkov Telescope Array (CTA) will be an instrument covering a wide energy range in very-high-energy (VHE) gamma rays. CTA will include several types of telescopes, in order to optimize the performance over the whole energy range. Both large-scale Monte Carlo (MC) simulations of CTA super-sets (including many different possible CTA layouts as sub-sets) and smaller-scale simulations dedicated to individual aspects were carried out and are on-going. We summarize results of the prior round of large-scale simulations, show where the design has now evolved beyond the conservative assumptions of the prior round and present first results from the on-going new round of MC simulations.Comment: 4 pages, 5 figures. In Proceedings of the 33rd International Cosmic Ray Conference (ICRC2013), Rio de Janeiro (Brazil). All CTA contributions at arXiv:1307.223

First detection of a VHE gamma-ray spectral maximum from a Cosmic source: H.E.S.S. discovery of the Vela X nebula

The Vela supernova remnant (SNR) is a complex region containing a number of sources of non-thermal radiation. The inner section of this SNR, within 2 degrees of the pulsar PSR B0833-45, has been observed by the H.E.S.S. gamma-ray atmospheric Cherenkov detector in 2004 and 2005. A strong signal is seen from an extended region to the south of the pulsar, within an integration region of radius 0.8 deg. around the position (RA = 08h 35m 00s, dec = -45 deg. 36' J2000.0). The excess coincides with a region of hard X-ray emission seen by the ROSAT and ASCA satellites. The observed energy spectrum of the source between 550 GeV and 65 TeV is well fit by a power law function with photon index = 1.45 +/- 0.09(stat) +/- 0.2(sys) and an exponential cutoff at an energy of 13.8 +/- 2.3(stat) +/- 4.1(sys) TeV. The integral flux above 1 TeV is (1.28 +/- 0.17 (stat) +/- 0.38(sys)) x 10^{-11} cm^{-2} s^{-1}. This result is the first clear measurement of a peak in the spectral energy distribution from a VHE gamma-ray source, likely related to inverse Compton emission. A fit of an Inverse Compton model to the H.E.S.S. spectral energy distribution gives a total energy in non-thermal electrons of ~2 x 10^{45} erg between 5 TeV and 100 TeV, assuming a distance of 290 parsec to the pulsar. The best fit electron power law index is 2.0, with a spectral break at 67 TeV.Comment: 5 pages, 4 figures, accepted for publication in Astronomy and Astrophysics letter

A possible association of the new VHE gamma-ray source HESS J1825--137 with the pulsar wind nebula G18.0--0.7

We report on a possible association of the recently discovered very high-energy $\gamma$-ray source HESS J1825--137 with the pulsar wind nebula (commonly referred to as G 18.0--0.7) of the $2.1\times 10^{4}$ year old Vela-like pulsar PSR B1823--13. HESS J1825--137 was detected with a significance of 8.1 $\sigma$ in the Galactic Plane survey conducted with the H.E.S.S. instrument in 2004. The centroid position of HESS J1825--137 is offset by 11\arcmin south of the pulsar position. \emph{XMM-Newton} observations have revealed X-ray synchrotron emission of an asymmetric pulsar wind nebula extending to the south of the pulsar. We argue that the observed morphology and TeV spectral index suggest that HESS J1825--137 and G 18.0--0.7 may be associated: the lifetime of TeV emitting electrons is expected to be longer compared to the {\it XMM-Newton} X-ray emitting electrons, resulting in electrons from earlier epochs (when the spin-down power was larger) contributing to the present TeV flux. These electrons are expected to be synchrotron cooled, which explains the observed photon index of $\sim 2.4$, and the longer lifetime of TeV emitting electrons naturally explains why the TeV nebula is larger than the X-ray size. Finally, supernova remnant expansion into an inhomogeneous medium is expected to create reverse shocks interacting at different times with the pulsar wind nebula, resulting in the offset X-ray and TeV $\gamma$-ray morphology.Comment: 5 pages, 3 figures, to appear in Astronomy and Astrophysics Letter

Very high energy gamma rays from the direction of Sagittarius A*.

We report the detection of a point-like source of very high energy (VHE) -rays coincident within 1' of Sgr A *, obtained with the HESS array of Cherenkov telescopes. The -rays exhibit a power-law energy spectrum with a spectral index of and a flux above the 165 GeV threshold of m -2 s -1. The measured flux and spectrum differ substantially from recent results reported in particular by the CANGAROO collaboration