The results of investigations of current-voltage characteristics for metal-dielectric-metal and metal-dielectric-semiconductor-metal structures, where crystalline and glass lithium borates used as ...dielectrics, are presented.
The ATIC long duration balloon project Guzik, T.G.; Adams, J.H.; Ahn, H.S. ...
Advances in space research,
2004, 2004-1-00, 20040101, Letnik:
33, Številka:
10
Journal Article
Recenzirano
Long Duration Balloon (LDB) scientific experiments, launched to circumnavigate the south pole over Antarctica, have particular advantages compared to Shuttle or other Low Earth Orbit (LEO) missions ...in terms of cost, weight, scientific “duty factor” and work force development. The Advanced Thin Ionization Calorimeter (ATIC) cosmic-ray astrophysics experiment is a good example of a university-based project that takes full advantage of current LDB capability. The ATIC experiment is currently being prepared for its first LDB science flight that will investigate the charge composition and energy spectra of primary cosmic-rays over the energy range from about 10
10 to 10
14 eV. The instrument is built around a fully active, Bismuth–Germanate (BGO) ionization calorimeter to measure the energy deposited by cascades formed by particles interacting in a thick carbon target. A highly segmented silicon matrix, located above the target, provides good incident charge resolution plus rejection of “backscattered” particles from the cascade. Trajectory reconstruction is based on the cascade profile in the BGO calorimeter, plus information from the three pairs of scintillator hodoscope layers in the target section above it. A full evaluation of the experiment was performed during a test flight occurring between 28 December 2000 and 13 January 2001 where ATIC was carried to an altitude of ∼37 km above Antarctica by a ∼850,000 m
3 helium filled balloon for one circumnavigation of the continent. All systems behaved well, the detectors performed as expected, >43 GB of engineering and cosmic-ray event data were returned and these data are now undergoing preliminary data analysis. During the coming 2002–2003 Antarctica summer season, we are preparing for an ATIC science flight with ∼15 to 30 days of data collection in the near-space environment of Long Duration Balloon (LDB) float altitudes.
A strong excess in a form of a wide peak in the energy range of 300-800 GeV was discovered in the first measurements of the electron spectrum in the energy range from 20 GeV to 3 TeV by the ...balloon-borne experiment ATIC (J. Chang et al. Nature, 2008). The experimental data processing and analysis of the electron spectrum with different criteria for selection of electrons, completely independent of the results reported in (J. Chang et al. Nature, 2008) is employed in the present paper. The new independent analysis generally confirms the results of (J. Chang et al. Nature, 2008), but shows that the spectrum in the region of the excess is represented by a number of narrow peaks. The measured spectrum is compared to the spectrum of (J. Chang et al. Nature, 2008) and to the spectrum of the Fermi/LAT experiment.
Objective: to analyze changes of serum calprotectin (CP) concentration, its relationship to the clinical and laboratory parameters of rheumatoid arthritis (RA) activity, and the significance of ...baseline CP level for predicting therapeutic response in RA patients treated with etanercept (ETC).Subjects and methods. A total of 84 patients with moderate and high RA activity (mean DAS28 6.35±0.92) who had been ineffectively treated with disease-modifying antirheumatic drugs were examined. The patients received ETC 50 mg/week subcutaneously for 34 weeks. To assess RA activity, tender and swollen joint count, pain, patient’s and physician’s assessment of global disease activity on 100-mm visual analogue scale and DAS28 were used. Functional status was evaluated by HAQ and RAPID3. Treatment efficacy was assessed according to the European League against Rheumatism (EULAR) criteria and the American College of Rheumatology (ACR) criteria. Serum concentration of CP was tested before, 12 and 25 weeks after start of therapy.Results and discussion. There was a statistically significant (p < 0.0001) decrease in CP concentrations after 12 weeks of ETC therapy. Later (after 25 weeks) CP level remained essentially unchanged. CP concentration correlated with erythrocyte sedimentation rate, C-reactive protein level, swollen joint count, and DAS28. Baseline CP level was not a predictor for achieving the therapeutic response according to the EULAR and ACR criteria. In a group of patients unresponsive to treatment according to the EULAR criteria, CP levelrose at 25 weeks whereas it fell during clinical improvement. In the patients achieving ACR 50 and 70% response, changes of CP level were significantly better than those in the other patients.Conclusion. ETC therapy caused a considerable reduction of CP level, clinical and laboratory parameters of RA activity. The baseline concentration of CP was not a predictor for achieving the response to ETC treatment.
Tunka-HiSCORE (HiSCORE: Hundred Square-km Cosmic Origin Explorer) is a new Cherenkov EAS array for multi-TeV gamma -ray gamma -ray astronomy and cosmic ray studies. The array will consist of ...wide-angle (0.6 sr) optical stations with 150 m distance between individual stations. The array will be constructed in several stages: beginning with a 1 km2 array at the first stage up to 100 km2 at the last stage. The first three stations have been installed during 2012 in Tunka Valley (50 km from the Southern tip of Lake Baikal) at the site of the Tunka-133 array. We describe the construction of the optical stations and the array DAQ, and present the first results of common operation of the new optical stations with the Tunka-133 array.
A new EAS Cherenkov light array, Tunka-133, with ~1 km^2 geometrical area has been installed at the Tunka Valley (50 km from Lake Baikal) in 2009. The array permits a detailed study of cosmic ray ...energy spectrum and mass composition in the energy range 10^16 - 10^18 eV with a uniform method. We describe the array construction, DAQ and methods of the array calibration.The method of energy reconstruction and absolute calibration of measurements are discussed. The analysis of spatial and time structure of EAS Cherenkov light allows to estimate the depth of the EAS maximum X_max. The results on the all particles energy spectrum and the mean depth of the EAS maximum X_max vs. primary energy derived from the data of two winter seasons (2009 -- 2011), are presented. Preliminary results of joint operation of the Cherenkov array with antennas for detection of EAS radio signals are shown. Plans for future upgrades -- deployment of remote clusters, radioantennas and a scintillator detector network and a prototype of the HiSCORE gamma-telescope -- are discussed.
Coenzyme A functions as a carrier of acetyl and acyl groups in living cells and is essential for numerous biosynthetic, energy-yielding, and degradative metabolic pathways. There are five enzymatic ...steps in CoA biosynthesis. To date, molecular cloning of enzymes involved in the CoA biosynthetic pathway in mammals has been only reported for pantothenate kinase. In this study, we present cDNA cloning and functional characterization of CoA synthase. It has an open reading frame of 563 aa and encodes a protein of approximately 60 kDa. Sequence alignments suggested that the protein possesses both phosphopantetheine adenylyltransferase and dephospho-CoA kinase domains. Biochemical assays using wild type recombinant protein confirmed the gene product indeed contained both these enzymatic activities. The presence of intrinsic phosphopantetheine adenylyltransferase activity was further confirmed by site-directed mutagenesis. Therefore, this study describes the first cloning and characterization of a mammalian CoA synthase and confirms this is a bifunctional enzyme containing the last two components of CoA biosynthesis.
The Ultra-Fast Flash Observatory (UFFO) pathfinder is a space mission devoted to the measurement of Gamma-Ray Bursts (GRBs), especially their early light curves which will give crucial information on ...the progenitor stars and central engines of the GRBs. It consists of two instruments: the UFFO Burst Alert & Trigger telescope (UBAT) for the detection of GRB locations and the Slewing Mirror Telescope (SMT) for the UV/optical afterglow observations, upon triggering by UBAT. The UBAT employs a coded-mask {\gamma}/X-ray camera with a wide field of view (FOV), and is comprised of three parts: a coded mask, a hopper, and a detector module (DM). The UBAT DM consists of a LYSO scintillator crystal array, multi-anode photo multipliers, and analog and digital readout electronics. We present here the design and fabrication of the UBAT DM, as well as its preliminary test results.
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