143 research outputs found
Measurement of the lateral distribution function of UHECR air showers with the Pierre Auger Observatory
We describe how the lateral distribution function (LDF) is measured using the large sample of events recorded with the surface detector (SD) array and with a small sample observed with the fluorescence detectors (FD). For hybrid events, in which SD and FD measurements of the same shower are available, the core position is much better constrained than for SD-onlyevents, thus providing an important cross-check on the LDF determined from SD measurements alone.
[Segmento extraĂdo de la ponencia]Facultad de Ciencias Exacta
Blood sirt1 shows a coherent association with leptin and adiponectin in relation to the degree and distribution of adiposity: A study in obesity, normal weight and anorexia nervosa
Sirtuin 1 (SIRT1) is a sensor of cell energy availability, and with leptin and adiponectin. it regulates metabolic homeostasis. Widely studied in tissues, SIRT1 is under evaluation as a plasmatic marker. We aimed at assessing whether circulating SIRT1 behaves consistently with leptin and adiponectin in conditions of deficiency, excess or normal fat content. Eighty subjects were evaluated: 27 with anorexia nervosa (AN), 26 normal-weight and 27 with obesity. Bloodstream SIRT1, leptin and adiponectin (ELISA), total and trunk fat mass (FM) %, abdominal visceral adipose tissue, liver steatosis and epicardial fat thickness (EFT) were assessed. For each fat store, the coefficient of determination (R2 ) was used to evaluate the prediction capability of SIRT1, leptin and adiponectin. Plasma SIRT1 and adiponectin coherently decreased with the increase of FM, while the opposite occurred with leptin. Mean levels of each analyte were different between groups (p < 0.005). A significant association between plasma variables and FM depots was observed. SIRT1 showed a good predictive strength for FM, particularly in the obesity group, where the best R2 was recorded for EFT (R2 = 0.7). Blood SIRT1, adiponectin and leptin behave coherently with FM and there is synchrony between them. The association of SIRT1 with FM is substantially superimposable to that of adiponectin and leptin. Given its homeostatic roles, SIRT1 may deserve to be considered as a plasma clinical/biochemical parameter of adiposity and metabolic health
Idiopathic Pulmonary Fibrosis (IPF) incidence and prevalence in Italy
Background: Studies of Idiopathic Pulmonary Fibrosis (IPF) epidemiology show regional variations of
incidence and prevalence; no epidemiological studies have been carried out in Italy. Objective: To determine incidence
and prevalence rates of IPF in the population of a large Italian region.Methods: in this cross-sectional study
study data were collected on all patients of 18 years of age and older admitted as primary or secondary idiopathic
fibrosing alveolitis (ICD9-CM 516.3) to Lazio hospitals, from 1/1/2005 to 31/12/2009, using regional hospital
discharge, population and cause of death databases. Reporting accuracy was assessed on a random sample of hospital
charts carrying the ICD9-CM 516.3, 516.8, 516.9 and 515 codes, by reviewing radiology and pathology
findings to define cases as IPF âconfidentâ, âpossibleâ or âinconsistentâ. Results: Annual prevalence and incidence
of IPF were estimated at 25.6 per 100,000 and 7.5 per 100,000 using the ICD9-CM code 516.3 without chart
audit while they were estimated at 31.6 per 100,000 and at 9,3 per 100,000 for the IPF âconfidentâ definition after
hospital chart audit. Conclusion: The data provide a first estimate of IPF incidence in Italy and indicate that incidence
and prevalence in southern European regions may be similar to those observed in northern Europe and
North America. (Sarcoidosis Vasc Diffuse Lung Dis 2014; 31: 191-197
Calibration of the surface array of the Pierre Auger Observatory
The Pierre Auger Observatory is designed to study cosmic rays of the highest energies (>eV). The ground array of the Observatory will consist of 1600 water Cherenkov detectors deployed over 3000 km. The remoteness and large number of detectors require a robust, automatic self-calibration procedure. It relies on the measurement of the average charge collected by a photomultiplier tube from the Cherenkov light produced by a vertical and central through-going muon, determined to 5â10% at the detector via a novel rate-based technique and to 3% precision through analysis of histograms of the charge distribution. The parameters needed for the calibration are measured every minute, allowing for an accurate determination of the signals recorded from extensive air showers produced by primary cosmic rays. The method also enables stable and uniform triggering conditions to be achieved
Measurement of the Depth of Maximum of Extensive Air Showers above 10^18 eV
We describe the measurement of the depth of maximum, Xmax, of the
longitudinal development of air showers induced by cosmic rays. Almost four
thousand events above 10^18 eV observed by the fluorescence detector of the
Pierre Auger Observatory in coincidence with at least one surface detector
station are selected for the analysis. The average shower maximum was found to
evolve with energy at a rate of (106 +35/-21) g/cm^2/decade below 10^(18.24 +/-
0.05) eV and (24 +/- 3) g/cm^2/decade above this energy. The measured
shower-to-shower fluctuations decrease from about 55 to 26 g/cm^2. The
interpretation of these results in terms of the cosmic ray mass composition is
briefly discussed.Comment: Accepted for publication by PR
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