1,004 research outputs found
Joint H.E.S.S. and Fermi-LAT analysis of the region around PSR J1813-1749
HESS J1813-178 is one of the brightest sources detected during the first HESS
Galactic Plane survey. The compact source, also detected by MAGIC, is believed
to be a pulsar wind nebula powered by one of the most powerful pulsars known in
the Galaxy, PSR J1813-1749 with a spin-down luminosity of . With its extreme physical
properties, as well as the pulsar's young age of 5.6 kyrs, the -rays
detected in this region allow us to study the evolution of a highly atypical
system. Previous studies of the region in the GeV energy range show emission
extended beyond the size of the compact H.E.S.S. source. Using the archival
H.E.S.S. data with improved background methods, we perform a detailed
morphological and spectral analysis of the region. Additionally to the compact,
bright emission component, we find significantly extended emission, whose
position is coincident with HESS J1813-178. We reanalyse the region in GeV and
derive a joint-model in order to find a continuous description of the emission
in the region from GeV to TeV. Using the results derived in this analysis, as
well as X-ray and radio data of the region, we perform multi-wavelength
spectral modeling. Possible hadronic or leptonic origins of the -ray
emission are investigated, and the diffusion parameters necessary to explain
the extended emission are examined.Comment: 8 pages, 4 figures, 1 table, In proceedings of ICRC202
Imaging photomultiplier array with integrated amplifiers and high-speed USB interface
Multianode photomultiplier tube (PMT) arrays are finding application as convenient high-speed light sensitive devices for plasma imaging. This paper describes the development of a USB-based "plug-n-play" 16-channel PMT camera with 16 bits simultaneous acquisition of 16 signal channels at rates up to 2 MSs per channel. The preamplifiers and digital hardware are packaged in a compact housing which incorporates magnetic shielding, on-board generation of the high-voltage PMT bias, an optical filter mount and slits, and F-mount lens adaptor. Triggering, timing, and acquisition are handled by four field-programmable gate arrays (FPGAs) under instruction from a master FPGA controlled by a computer with a LABVIEW interface. We present technical design details and specifications and illustrate performance with high-speed images obtained on the H-1 heliac at the ANU
Taking nature into lab: biomineralization by heavy metal-resistant streptomycetes in soil
Biomineralization by heavy metal-resistant streptomycetes was tested to evaluate the potential influence on metal mobilities in soil. Thus, we designed an experiment adopting conditions from classical laboratory methods to natural conditions prevailing in metal-rich soils with media spiked with heavy metals, soil agar, and nutrientenriched or unamended soil incubated with the bacteria. As a result, all strains were able to form struvite minerals (MgNH4PO4 6H2O) on tryptic soy broth (TSB)-media supplemented with AlCl3, MnCl2 and CuSO4, as well as on soil agar. Some strains additionally formed struvite on nutrient-enriched contaminated and control soil, as well as on metal contaminated soil without addition of media components. In contrast, switzerite (Mn3(PO4)2 7H2O) was exclusively formed on minimal media spiked with MnCl2 by four heavy metal-resistant strains, and on nutrient-enriched control soil by one strain. Hydrated nickel hydrogen phosphate was only crystallized on complex media supplemented with NiSO4 by most strains. Thus, mineralization is a dominant property of streptomycetes, with different processes likely to occur under laboratory conditions and sub-natural to natural conditions. This new understanding might have implications for our understanding of biological metal resistance mechanisms. We assume that biogeochemical cycles, nutrient storage and metal resistance might be affected by formation and re-solubilization of minerals like struvite in soil at microscale
Carbon nanoparticles fabricated by infrared laser ablation of graphite and polycrystalline diamond targets
This paper presents the results of carbon nanoparticles (CNPs) production by infrared laser ablation of a graphite or a polycrystalline diamond target, submerged in one of two solvents, water or isopropanol. The targets were irradiated using a SPI fibre laser with a wavelength of 1064nm being operated at different average powers. After laser-assisted synthesis of CNPs, the resulting colloids, i.e particles in a liquid medium, were examined using the analytical techniques of dynamic light scattering, UV-Vis, Raman spectroscopy and fluorescence spectroscopy. The results show that the properties of CNPs strongly depend on processing conditions of the liquid phase-pulsed laser ablation (LP-PLA) process. In particular, the size of nanoparticles produced are affected by the processing parameters of the laser ablation. The results show that the laser processing of a graphite target in deionised water and in isopropanol produces carbon nanoparticles with properties that are beneficial for various biochemical and biomedical applications. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinhei
A multichannel magnetic probe system for analysing magnetic fluctuations in helical axis plasmas
The need to understand the structure of magnetic fluctuations in H-1NF heliac [S. Hamberger et al., Fusion Technol. 17, 123 (1990)] plasmas has motivated the installation of a sixteen former, tri-axis helical magnetic probe Mirnov array (HMA). The new array complements two existing poloidal Mirnov arrays by providing polarisation information, higher frequency response, and improved toroidal resolution. The helical placement is ideal for helical axis plasmas because it positions the array as close as possible to the plasma in regions of varying degrees of favourable curvature in the magnetohydrodynamic sense, but almost constant magnetic angle. This makes phase variation with probe position near linear, greatly simplifying the analysis of the data. Several of the issues involved in the design, installation, data analysis, and calibration of this unique array are presented including probe coil design, frequency response measurements, mode number identification, orientation calculations, and mapping probe coil positions to magnetic coordinates. Details of specially designed digitally programmable pre-amplifiers, which allow gains and filters to be changed as part of the data acquisition initialisation sequence and stored with the probe signals, are also presented. The low shear heliac geometry [R. Jiménez-Gómez et al., Nucl. Fusion 51, 033001 (2011)], flexibility of the H-1NF heliac, and wealth of information provided by the HMA create a unique opportunity for detailed study of Alfvén eigenmodes, which could be a serious issue for future fusion reactors.This work was supported by the Education Investment Fund
under the Super Science Initiative of the Australian Government.
S.R.H. wishes to thank AINSE Ltd. for providing financial
assistance to enable this work on H-1NF to be conducted
Acetylcholinesterase, Tyrosinase, α-Glucosidase inhibition by Ammodaucus leucotrichus Coss. & Dur. Fruits Essential oil and Ethanolic Extract and Molecular Docking Analysis
Medicinal and aromatic plants serve as valuable reservoirs of bioactive molecules and mineral compounds that are harnessed for therapeutic and agro-food applications. The objective of this study was to assess the inhibitory enzyme properties of Ammodaucus leucotrichus Coss & Dur fruit essential oil, as well as its aqueous and ethanol extracts, against acetylcholinesterase, tyrosinase, and α-glucosidase. Additionally, the antioxidant activity of these natural mixtures was evaluated using three different methods: DPPH, FRAP, and β-carotene bleaching tests. Furthermore, this research endeavors to examine the mineral constituents of various components of the plant under investigation. The various natural combinations that were examined exhibited a notable inhibitory impact on the enzymes acetylcholinesterase (67.56-92.30%), tyrosinase (57.52-63.44%), and α-glucosidase (61.22-72.49%). The analyzed extracts also demonstrate a significant antioxidant activity. Furthermore, the results obtained from the analysis indicate a notable presence of both macro and microelements, such as calcium (2.028 mg/g for leaves and 1.787 mg/g for fruits), within the Ammodaucus leucotrichus Coss & Dur plant. The current study supports the significance of utilizing Ammodaucus leucotrichus Coss & Dur fruits in the medicinal and agro-alimentary sectors. The utilization of molecular docking techniques was employed in order to make predictions regarding the therapeutic effects of Ammodaucus leucotrichus Coss & Dur fruits
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