247 research outputs found
MARS, the MAGIC Analysis and Reconstruction Software
With the commissioning of the second MAGIC gamma-ray Cherenkov telescope
situated close to MAGIC-I, the standard analysis package of the MAGIC
collaboration, MARS, has been upgraded in order to perform the stereoscopic
reconstruction of the detected atmospheric showers. MARS is a ROOT-based code
written in C++, which includes all the necessary algorithms to transform the
raw data recorded by the telescopes into information about the physics
parameters of the observed targets. An overview of the methods for extracting
the basic shower parameters is presented, together with a description of the
tools used in the background discrimination and in the estimation of the
gamma-ray source spectra.Comment: 4 pages, 0 figures, submitted to the 31st International Cosmic Ray
Conference, {\L}odz 200
The MAGIC Experiment and Its First Results
With its diameter of 17m, the MAGIC telescope is the largest Cherenkov
detector for gamma ray astrophysics. It is sensitive to photons above an energy
of 30 GeV. MAGIC started operations in October 2003 and is currently taking
data. This report summarizes its main characteristics, its rst results and its
potential for physics.Comment: 6 pages, 3 figures, to be published in the Proceedings of the 6th
International Symposium ''Frontiers of Fundamental and Computational
Physics'' (FFP6), Udine (Italy), Sep. 26-29, 200
A novel background reduction strategy for high level triggers and processing in gamma-ray Cherenkov detectors
Gamma ray astronomy is now at the leading edge for studies related both to
fundamental physics and astrophysics. The sensitivity of gamma detectors is
limited by the huge amount of background, constituted by hadronic cosmic rays
(typically two to three orders of magnitude more than the signal) and by the
accidental background in the detectors. By using the information on the
temporal evolution of the Cherenkov light, the background can be reduced. We
will present here the results obtained within the MAGIC experiment using a new
technique for the reduction of the background. Particle showers produced by
gamma rays show a different temporal distribution with respect to showers
produced by hadrons; the background due to accidental counts shows no
dependence on time. Such novel strategy can increase the sensitivity of present
instruments.Comment: 4 pages, 3 figures, Proc. of the 9th Int. Syposium "Frontiers of
Fundamental and Computational Physics" (FFP9), (AIP, Melville, New York,
2008, in press
AGEs, FGF-23 and Cardiovascular remodeling in Chronic Kidney Disease on Dialysis (CKD-G5D): The Protective Role of sRAGE
Introduction. High levels of advanced glycated products (AGEs) and fibroblast growth factor-23 (FGF-23) are recognized as important cardiovascular risk factors. In chronic kidney disease (CKD), FGF-23 increases as a compensatory mechanism to keep normal phosphate and AGEs accumulate due both to the increased formation and reduced elimination. Being by-products of hyperglycemia, the formation of AGEs is further increased in patients with diabetes mellitus (DM). Recently, AGEs have been shown to induce cardiac remodeling in a mouse model of renal failure by promoting FGF-23 expression. Our aim was to explore whether Chronic Kidney Disease on dialysis (CKD-G5D) with DM suffer of an increased cardiac remodeling due to the to increased AGEs formation and the further amplification of the FGF-23 response.
Methods. We quantified plasma levels of glycated albumin (GA), sRAGE, the decoy receptor for AGEs, c-terminal FGF-23 (cFGF23), brain natriuretic peptide (BNP) and the inflammatory mediators C-reactive protein, tumor necrosis factor alpha and pentraxin-3 in 24 CKD-G5D patients with DM and 52 without DM.
Results. The levels of sRAGE, cFGF-23, BNP and the pro-inflammatory markers evaluated were over the ranges of normality in both DM and non-DM groups. GA and sRAGE were increased in DM CKD-G5D compared to non-DM CKD-G5D patients but cFGF-23 did not differ between the two groups. Similarly, the concentrations of the pro-inflammatory molecules and BNP were almost the same in the two groups.
Conclusions. The up-regulation of sRAGE could be a counteract-system against glycated products. sRAGE, by blocking glycated products, could reduce the activation of various damaging cellular mechanisms, including an increased stimulation of cFGF-23and inflammatory mediators. Indeed, since AGEs accumulation is a risk factor for development and progression of heart failure, the lack of difference also in BNP levels between the two groups reinforces the hypothesis of a protective role of sRAGE in DM CKD-G5D patients
Increased Levels of sRAGE in Diabetic CKD-G5D Patients : a Potential Protective Mechanism Against AGE-Related Up-Regulation of Fibroblast Growth Factor-23 and Inflammation
Advanced glycation end products (AGEs) may induce cardiac remodeling in kidney disease by promoting fibroblast growth factor 23 (FGF-23) expression. Since AGEs are increased in diabetes mellitus (DM), our first aim was to evaluate the existence of any potential association between AGEs, FGF-23, inflammation, and increased cardiovascular risk in DM patients on dialysis (CKD-G5D). Secondarily, we explored the potential role of the soluble receptor for AGEs (sRAGE) as a marker of heart failure. Levels of glycated albumin (GA), sRAGE, c-terminal FGF-23 (cFGF-23), brain natriuretic peptide (BNP), and inflammatory mediators were compared between DM and non-DM CKD-G5D patients. The levels of sRAGE, cFGF-23, BNP, and proinflammatory markers were over the ranges of normality in both DM and non-DM groups. Only GA and sRAGE levels were increased in DM compared to non-DM patients. Plasma levels of sRAGE and CRP were the only independent predictors of BNP concentration. In conclusion, in DM CKD-G5D patients, sRAGE appeared to be a marker of cardiac remodeling. Indeed, its increase could be a potential protective mechanism against the increased risk of cardiovascular complications related to AGEs and inflammation. The causal relationship between sRAGE and cardiovascular risk in these patients needs to be further confirmed by mechanistic studies
AGEs, FGF-23 and Cardiovascular remodeling in Chronic Kidney Disease on Dialysis (CKD-G5D): The Protective Role of sRAGE
Introduction. High levels of advanced glycated products (AGEs) and fibroblast growth factor-23 (FGF-23) are recognized as important cardiovascular risk factors. In chronic kidney disease (CKD), FGF-23 increases as a compensatory mechanism to keep normal phosphate and AGEs accumulate due both to the increased formation and reduced elimination. Being by-products of hyperglycemia, the formation of AGEs is further increased in patients with diabetes mellitus (DM). Recently, AGEs have been shown to induce cardiac remodeling in a mouse model of renal failure by promoting FGF-23 expression. Our aim was to explore whether Chronic Kidney Disease on dialysis (CKD-G5D) with DM suffer of an increased cardiac remodeling due to the to increased AGEs formation and the further amplification of the FGF-23 response.
Methods. We quantified plasma levels of glycated albumin (GA), sRAGE, the decoy receptor for AGEs, c-terminal FGF-23 (cFGF23), brain natriuretic peptide (BNP) and the inflammatory mediators C-reactive protein, tumor necrosis factor alpha and pentraxin-3 in 24 CKD-G5D patients with DM and 52 without DM.
Results. The levels of sRAGE, cFGF-23, BNP and the pro-inflammatory markers evaluated were over the ranges of normality in both DM and non-DM groups. GA and sRAGE were increased in DM CKD-G5D compared to non-DM CKD-G5D patients but cFGF-23 did not differ between the two groups. Similarly, the concentrations of the pro-inflammatory molecules and BNP were almost the same in the two groups.
Conclusions. The up-regulation of sRAGE could be a counteract-system against glycated products. sRAGE, by blocking glycated products, could reduce the activation of various damaging cellular mechanisms, including an increased stimulation of cFGF-23and inflammatory mediators. Indeed, since AGEs accumulation is a risk factor for development and progression of heart failure, the lack of difference also in BNP levels between the two groups reinforces the hypothesis of a protective role of sRAGE in DM CKD-G5D patients
First bounds on the very high energy gamma-ray emission from Arp 220
Using the Major Atmospheric Gamma Imaging Cherenkov Telescope (MAGIC), we
have observed the nearest ultra-luminous infrared galaxy Arp 220 for about 15
hours. No significant signal was detected within the dedicated amount of
observation time. The first upper limits to the very high energy -ray
flux of Arp 220 are herein reported and compared with theoretical expectations.Comment: Accepted for publication in Ap
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