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Search Results: 1 - 10 of 325323 matches for " S. Chiodini "
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Characterization of Prototype BTeV Silicon Pixel Sensors Before and After Irradiation
Maria R. Coluccia,J. A. Appel,G. Chiodini,D. C. Christian,S. Kwan
Physics , 2002, DOI: 10.1109/TNS.2002.801710
Abstract: We report on measurements performed on silicon pixel sensor prototypes exposed to a 200 MeV proton beam at the Indiana University Cyclotron Facility. The sensors are of n+/n/p+ type with multi-guard ring structures on the p+-side and p-stop electrode isolation on the n+-side. Electrical characterization of the devices was performed before and after irradiation up to a proton fluence of 4E14 p/cm2. We tested pixel sensors fabricated from normal and oxygen-enriched silicon wafers and with two different p-stop isolation layouts: common p-stop and individual p-stop.
On the Unruh effect in de Sitter space
R. Casadio,S. Chiodini,A. Orlandi,G. Acquaviva,R. Di Criscienzo,L. Vanzo
Physics , 2010, DOI: 10.1142/S0217732311036516
Abstract: We give an interpretation of the temperature in de Sitter universe in terms of a dynamical Unruh effect associated with the Hubble sphere. As with the quantum noise perceived by a uniformly accelerated observer in static space-times, observers endowed with a proper motion can in principle detect the effect. In particular, we study a "Kodama observer" as a two-field Unruh detector for which we show the effect is approximately thermal. We also estimate the back-reaction of the emitted radiation and find trajectories associated with the Kodama vector fields are stable.
Single Event Effects in the Pixel readout chip for BTeV
G. Chiodini,J. A. Appel,G. Cardoso,D. C. Christian,M. R. Coluccia,J. Hoff,S. W. Kwan,A. Mekkaoui,R. Yarema,S. Zimmermann
Physics , 2001, DOI: 10.1016/S0168-9002(02)02030-2
Abstract: In future experiments the readout electronics for pixel detectors is required to be resistant to a very high radiation level. In this paper we report on irradiation tests performed on several preFPIX2 prototype pixel readout chips for the BTeV experiment exposed to a 200 MeV proton beam. The prototype chips have been implemented in commercial 0.25 um CMOS processes following radiation tolerant design rules. The results show that this ASIC design tolerates a large total radiation dose, and that radiation induced Single Event Effects occur at a manageable level.
Parallel determination of NeuroD1, Chromogranin-A, KI67 and androgen receptor expression in surgically treated prostate cancers
Cindolo, L.;Cantile, M.;Franco, R.;Chiodini, P.;Schiavo, G.;Forte, I.;Zlobec, I.;Salzano, L.;Botti, G.;Gidaro, S.;Terracciano, L.;Cillo, C.;
International braz j urol , 2011, DOI: 10.1590/S1677-55382011000100008
Abstract: purpose: neuroendocrine differentiation is a hallmark of prostate cancer. the aim of our study was the detection of the parallel expression of neuroendocrine related markers using a prostate tissue microarray (tma). materials and methods: our study was aimed at detecting the parallel expression of neurod1, chromogranin-a (chra), androgen receptor (ar) and ki-67 by immunohistochemistry on prostate cancer tissue microarray. the data was analyzed using sas version 8.2 (sas inc, cary, nc). the relationships between neurod1, chra and ar expressions and patients' characteristics were investigated by multivariate logistic regression analysis. progression and overall survival (os) distributions were calculated using kaplan-meier method. results: tissue reactivity for neurod1, chra and ar concerned 73%, 49% and 77% of the available cases, respectively. regarding overall survival, there were 87 deaths and 295 patients alive/censored (6 years of median follow-up). seventy-seven disease progressions occurred at the median follow-up 5.4y. a significant correlation between neurod1, chra and ar expression was observed (p < 0.001 and p < 0.03, respectively). additionally, chra was strongly associated in multivariate analysis to gleason score and ki67 expression (p < 0.009 and p < 0.0052, respectively). survival analysis showed no association between markers neither for overall nor for cancer-specific survival. conclusions: the results highlight that neurod1, chromogranin-a and androgen receptor are strongly associated, however their expression does not correlate with overall survival or disease progression.
ATLAS RPC Quality Assurance results at INFN Lecce
M. Bianco,I. Borjanovic,G. Cataldi,A. Cazzato,G. Chiodini,M. R. Coluccia,P. Creti,F. Grancagnolo,R. Perrino,M. Primavera,S. Spagnolo,G. Tassielli,A. Ventura
Physics , 2006,
Abstract: The main results of the quality assurance tests performed on the Resistive Plate Chamber used by the ATLAS experiment at LHC as muon trigger chambers are reported and discussed. Since July 2004, about 270 RPC units has been certified at INFN Lecce site and delivered to CERN, for being integrated in the final muon station of the ATLAS barrel region. We show the key RPC characteristics which qualify the performance of this detector technology as muon trigger chamber in the harsh LHC enviroments. These are dark current, chamber efficiency, noise rate, gas volume tomography, and gas leakage.
Numerical model of gas dispersion emitted from volcanic sources
A. Costa,G. Macedonio,G. Chiodini
Annals of Geophysics , 2005, DOI: 10.4401/ag-3236
Abstract: An Eulerian model for passive gas dispersion based on the K-theory for turbulent diffusion, coupled with a mass consistent wind model is presented. The procedure can be used to forecast gas concentration over large and complex terrains. The input to the model includes the topography, wind measurements from meteorological stations, atmospheric stability information and gas flow rate from the ground sources. Here, this model is applied to study the distribution of the CO2 discharged from the hot sources of the Solfatara Volcano, Naples, Italy, where the input data were measured during a 15 day campaign in June 2001 carried out to test an Eddy Covariance (EC) station by Osservatorio Vesuviano-INGV, Naples.
A Competitor of the Kolmogorov--Smirnov Test for the Goodness-of-fit Problem
Claudio Giovanni Borroni,Paola Maddalena Chiodini
International Journal of Statistics and Probability , 2013, DOI: 10.5539/ijsp.v2n1p1
Abstract: The classical goodness-of-fit problem, in the case of a null continuous and completely specified distribution, is faced by a new version of the Girone--Cifarelli test (see Girone, 1964; Cifarelli, 1974 & 1975). This latter test was introduced for the two-sample problem and showed a substantial gain of power over other common tests based on the empirical distribution function, notably over the Kolmogorov--Smirnov test. First, the problem of the re-definition of the Girone--Cifarelli test-statistic is considered, by reviewing the literature on the subject. A classical remark by Anderson (1962) is shown to be useful to choose the integrating function in the newly defined test-statistic. The sample properties of such a test-statistic are then studied. A table of critical values is obtained by simulation; moreover, the asymptotic null distribution is considered and its accuracy as an approximation of the finite distribution is discussed. Finally, a simulation study, considering a wide set of distributions mostly used in applications, is conducted to compare the proposed test with its classical competitors. The study gives some indications to locate such situations where the Girone-Cifarelli test performs at its best, notably over the Kolmogorov--Smirnov test.
Rare Earth Doped Silica Optical Fibre Sensors for Dosimetry in Medical and Technical Applications
N. Chiodini,A. Vedda,I. Veronese
Advances in Optics , 2014, DOI: 10.1155/2014/974584
Abstract: Radioluminescence optical fibre sensors are gaining importance since these devices are promising in several applications like high energy physics, particle tracking, real-time monitoring of radiation beams, and radioactive waste. Silica optical fibres play an important role thanks to their high radiation hardness. Moreover, rare earths may be incorporated to optimise the scintillation properties (emission spectrum, decay time) according to the particular application. This makes doped silica optical fibres a very versatile tool for the detection of ionizing radiation in many contexts. Among the fields of application of optical fibre sensors, radiation therapy represents a driving force for the research and development of new devices. In this review the recent progresses in the development of rare earth doped silica fibres for dosimetry in the medical field are described. After a general description of advantages and challenges for the use of optical fibre based dosimeter during radiation therapy treatment and diagnostic irradiations, the features of the incorporation of rare earths in the silica matrix in order to prepare radioluminescent optical fibre sensors are presented and discussed. In the last part of this paper, recent results obtained by using cerium, europium, and ytterbium doped silica optical fibres in radiation therapy applications are reviewed. 1. Introduction An optical fibre based dosimeter basically consists of a small scintillator coupled to a passive fibre of suitable length for remote signal transport to an optical detector (e.g., photomultiplier, photodiode, etc.). Such configuration has several advantages in radiation dosimetry applications. Indeed, the small volume of the detector makes the radiation field perturbation negligible, leading to high spatial resolution and point dose evaluations. These systems may enable a real-time measurement of the dose, providing a direct feedback to the medical physician during a radiation therapy (RT) treatment. In vivo measurements on patients take also advantage by the lack of any electrical supply. Furthermore, provided that a suitable scintillator material is used, an optical fibre based dosimeter is characterized by high sensitivity and reproducibility, independence of sensitivity upon accumulated dose, independence of the response from the environmental conditions, linearity of the response over a wide range of doses/dose rates, high radiation hardness, and nontoxicity for medical applications. However, for an effective use of these systems as dosimeters in RT, the stem effect, that is, the
Inter-rater reliability of malaria parasite counts and comparison of methods
Bowers Katherine,Bell David,Chiodini Peter,Barnwell John
Malaria Journal , 2009,
Abstract: Background The introduction of artemesinin-based treatment for falciparum malaria has led to a shift away from symptom-based diagnosis. Diagnosis may be achieved by using rapid non-microscopic diagnostic tests (RDTs), of which there are many available. Light microscopy, however, has a central role in parasite identification and quantification and remains the main method of parasite-based diagnosis in clinic and hospital settings and is necessary for monitoring the accuracy of RDTs. The World Health Organization has prepared a proficiency testing panel containing a range of malaria-positive blood samples of known parasitaemia, to be used for the assessment of commercially available malaria RDTs. Different blood film and counting methods may be used for this purpose, which raises questions regarding accuracy and reproducibility. A comparison was made of the established methods for parasitaemia estimation to determine which would give the least inter-rater and inter-method variation Methods Experienced malaria microscopists counted asexual parasitaemia on different slides using three methods; the thin film method using the total erythrocyte count, the thick film method using the total white cell count and the Earle and Perez method. All the slides were stained using Giemsa pH 7.2. Analysis of variance (ANOVA) models were used to find the inter-rater reliability for the different methods. The paired t-test was used to assess any systematic bias between the two methods, and a regression analysis was used to see if there was a changing bias with parasite count level. Results The thin blood film gave parasite counts around 30% higher than those obtained by the thick film and Earle and Perez methods, but exhibited a loss of sensitivity with low parasitaemia. The thick film and Earle and Perez methods showed little or no bias in counts between the two methods, however, estimated inter-rater reliability was slightly better for the thick film method. Conclusion The thin film method gave results closer to the true parasite count but is not feasible at a parasitaemia below 500 parasites per microlitre. The thick film method was both reproducible and practical for this project. The determination of malarial parasitaemia must be applied by skilled operators using standardized techniques.
In reply
Lanzetta Paolo,Chiodini Raffaella,Polito Antonio,Bandello Francesco
Indian Journal of Ophthalmology , 2003,
Abstract:
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