Giant Pair Halos Surrounding Non-Thermal Extragalactic Objects

Hochenergetische (E>100 GeV) Gammastrahlen aus extragalaktischen Quellen werden infolge der gamma-gamma-Paarbildung (PP) von der kosmischen Infrarot-Hintergrund-strahlung (CIB) absorbiert und loesen elektromagnetische Schauer durch Paarbildung und inverse Comptonstreuung aus. Dies fuehrt zur Ausbildung eines Elektron-Positron-Paarhalos, dessen Teilchenverteilung isotrop ist, falls ein genuegend starkes inter-galaktisches Magnetfeld (|B|> 1 nG) vorhanden ist. In dieser Arbeit wird eine Monte-Carlo Methode angewandt, bei der die Paarhalo-Energie und Winkelverteilungen fuer viele verschiedene Parameter (einlaufende Teilchen-verteilungen, CIB-Modelle und Rotverschiebungen) untersucht werden. Ein wichtiges Ergebnis ist der Nachweis einer Grenze der Empfindlichkeit der Paarhalo-Energie und der Winkelverteilungen auf die primaeren Gamma-Energien, oberhalb derer die Photonen mit der kosmischen Mikrowellen-Hintergrund-strahlung wechselwirken. Ausserdem wird gefunden, dass bei geringer Rotverschiebung das Spektrum des CIB einen staerkeren Einfluss auf die Paarhalo-Energie als auf die Winkelverteilungen hat. Fuer Quellen mit hoher Rotverschiebung kann ein Modellieren der Winkelverteilungen als indirektes Mittel zur Untersuchung der CIB Intensitaet dienen. Der moegliche Nachweis eines Paarhalos aus der Quelle H14236+428 wird diskutiert

Characterization of Bacillus species exhibiting strong proteolytic activity isolated from Thua Nao

In this study, two bacilli strains, namely TN51 and TN69, previously isolated from Thua Nao, a Thai traditional fermented soybean, were studied in terms of their phenotypic and biochemical properties. Initially, both strains were subjected to morphological determination and a series of biochemical tests. Both were Gram-positive, endosporeforming bacilli. Based on 16S rRNA gene sequence analysis, the identities of strains TN51 and TN69 were confirmed as Bacillus subtilis and B. cereus, respectively. In addition, these two strains were also assessed for their antibiogram profiles. It was found that both strains were susceptible to chloramphenicol, erythromycin, kanamycin, tetracycline, and vancomycin and resistant to ampicillin and intermediately susceptible to bacitracin

Very High Energy gamma-rays from electron/positron Pair Halos

In this paper we study the formation of giant electrons-positron pair halos around the powerful high energy extragalactic sources. We investigate the dependence of radiation of pair halos, in particular the spectral and angular distributions on the energy spectrum of the primary gamma-rays, the redshift of the source, and the flux of the extragalactic background light.Comment: 17 pages, 17 figures, published in Volume No. 18, Issue No. 06 of "International Journal Of Modern Physics D

EGMF Constraints from Simultaneous GeV-TeV Observations of Blazars

Attenuation of the TeV gamma-ray flux from distant blazars through pair production with extragalactic background light leads to the development of electromagnetic cascades and subsequent, lower energy, GeV secondary gamma-ray emission. Due to the deflection of VHE cascade electrons by extragalactic magnetic fields (EGMF), the spectral shape of this arriving cascade gamma-ray emission is dependent on the strength of the EGMF. Thus, the spectral shape of the GeV-TeV emission from blazars has the potential to probe the EGMF strength along the line of sight to the object. We investigate constraints on the EGMF derived from observations of blazars for which TeV observations simultaneous with those by the Fermi telescope were reported. We study the dependence of the EGMF bound on the hidden assumptions it rests upon. We select blazar objects for which simultaneous Fermi/LAT GeV and Veritas, MAGIC or HESS TeV emission have been published. We model the development of electromagnetic cascades along the gamma-ray beams from these sources using Monte Carlo simulations, including the calculation of the temporal delay incurred by cascade photons, relative to the light propagation time of direct gamma-rays from the source. Constraints on EGMF could be derived from the simultaneous GeV-TeV data on the blazars RGB J0710+591, 1ES 0229+200, and 1ES 1218+304. The measured source flux level in the GeV band is lower than the expected cascade component calculated under the assumption of zero EGMF. Assuming that the reason for the suppression of the cascade component is the extended nature of the cascade emission, we find that B>10^{-15} G (assuming EGMF correlation length of ~1 Mpc) is consistent with the data. Alternatively, the assumption that the suppression of the cascade emission is caused by the time delay of the cascade photons the data are consistent with B>10^{-17} G for the same correlation length.Comment: 9 pages, 9 figure

Additional four species of Tatraea (Leotiomycetes, Helotiales) in Yunnan Province, China

During the investigations of discomycetes in Yunnan, China, five species of Tatraea were discovered on decayed, decorticated oak trees or unidentified wood. All species have typical disc-like, large fruiting bodies with grey, brown or greyish-green colors. The ITS sequence analysis showed that they belong to Tatraea (Helotiaceae, Helotiales) and the LSU and ITS combination revealed a different topology within the genus. Four species, T. clepsydriformis, T. griseoturcoisina, T. yunnanensis and T. yuxiensis were established as new species, and T. aseptata was collected and described on oak woods. The pairwise homoplasy index (PHI) test results indicated that there is no significant genetic recombination (Φw = 1.0) between all related species pairs. All the species described here are supported by descriptions, illustrations and multi-gene analyses

Determination of volatile components in fermented soybean prepared by a co-culture of Bacillus subtilis and Rhizopus oligosporus

Fermented soybeans are traditional foods widely consumed in many countries (i.e., Natto in Japan, Jang in Korea, Kinema in India, Douichi in China, and Thua Nao in Thailand). In this study, an attempt was made with an expectation to improve the fermentation process using a co-culture of Bacillus subtilis and Rhizopus oligosporus. Initially, the raw soybeans were washed, sterilized by autoclaving, and inoculated with two inocula; for this, three different ratios between B. subtilis and R. oligosporus used were 100:0, 50:50, and 0:100. The fermentation was then carried out at 30°C for 3 days. The volatile compounds in the non-fermented and the fermented soybean products were determined by gas chromatography/ mass spectrometry (GC/MS) and extracted using a solid phase microextraction (SPME) technique. In total, 165 compounds were identified in the non-fermented and the fermented soybean products. For the non-fermented products, the predominant volatile compounds were alcohols (25.81%), aldehydes (13.64%), acids and esters (7.57%), furans (6.13%) and ketones (0.88%). In contrast, the major volatiles compounds presented in the fermented soybeans were as follows: i) The treatment of 100:0 consisted of acids and esters (35.89%), alcohols (14.55%), aldehydes (8.72%), ketones (4.97%), pyrazines (4.87%), and furans (4.22%); ii) 50:50 comprised of acids and esters (55.62%), alcohols (16.22%), aldehydes (7.80%), pyrazine (3.65%), ketones (2.55%), furans (1.67%), and aromatic compounds (1.46%); and iii) 0:100 included acids and esters (66.50%), alcohols (15.44%), aldehydes (2.59%), ketones (2.72%), furans (1.89%), aromatic compounds (1.80%), pyrazines (1.35%), and sulphur containing compounds (0.24%) respectively