2,419 research outputs found
Coming home to mother
No full textGift of Dr. Mary Jane Esplen.Piano vocal [instrumentation]We love to think of years ago [first line]We are coming home to Mother [first line of chorus]A flat [key]Piano [tempo]House, families, birds, photograph of M.E. Mollins [illustration]Popular song [form/genre]Publisher's advertisement on inside front [note]Mediatoon by G.A. Boyton [note
M.E. Church exterior
No full textA monochrome postcard of the M.E. Church in Georgetown, Delaware. The church was made out of brick and had a tall tower on its corner. Writing on the right indicates that the author was having a good time. Mrs. P. H. Adkins of Milton, Delaware, received this postcard. A postmark on the back indicates that this postcard was mailed from Georgetown, Delaware. The postage stamp is a one-cent U.S. #300, Benjamin Franklin. The back of the postcard is labeled 75.00 and 0240
M.E. Church exterior
No full textA monochrome postcard of the M.E. Church in Georgetown, Delaware. The church was made out of brick and had a tall tower on its corner. Writing on the right indicates that the author was having a good time. Mrs. P. H. Adkins of Milton, Delaware, received this postcard. A postmark on the back indicates that this postcard was mailed from Georgetown, Delaware. The postage stamp is a one-cent U.S. #300, Benjamin Franklin. The back of the postcard is labeled 75.00 and 0240
Simulated and experimental spectroscopic performance of GaAs X-ray pixel detectors
No full textIn pixel detectors, the electrode geometry affects the signal shape and therefore the spectroscopic performance of the device. This effect is enhanced in semiconductors where carrier trapping is relevant. In particular, semi insulating (SI) GaAs crystals present an incomplete charge collection due to a high concentration of deep traps in the bulk. In the last few years, SI GaAs pixel detectors have been developed as soft X-ray detectors for medical imaging applications. In this paper, we present a numerical method to evaluate the local charge collection properties of pixel detectors. A bi-dimensional description has been used to represent the detector geometry, According to recent models, the active region of a reverse biased SI GaAs detector is almost neutral. Therefore, the electrostatic potential inside a full active detector has been evaluated using the Laplace equation. A finite difference method with a fixed step orthogonal mesh has been adopted. The photon interaction point has been generated with a Monte Carlo method according to the attenuation length of a monochromatic X-ray beam in GaAs. The number of photogenerated carriers for each interaction has been extracted using a gaussian distribution. The induced signal on the collecting electrode has been calculated according to the Ramo's theorem and the trapping effect has been modeled introducing electron and hole lifetimes. The noise of the charge preamplifier have been also taken into account. A comparison between simulated and experimental X-ray spectra from a Am-241 source acquired with different GaAs pixel detectors has been carried out. (C) 2001 Elsevier Science B.V. All rights reserved
On using Directional Information for Parameter Space Decomposition in Ellipse Detection
No full textIn this paper we use the parametric polar representation to extend the application of edge directional information from circle to ellipse extraction. As a result we obtain a mapping which decomposes the parameter space required for ellipse extraction into two independent sub-spaces and one final histogram accumulator. The mapping includes the tangent of the angle of the first and second directional derivatives. These tangents are computed by considering edge direction at two border points. We show that the use of gradient information for parameter space decomposition avoids the intensive point labelling imposed by geometric constraints used by other approaches
La fecondazione assistita dopo dieci anni di legge 40 : il punto di vista del costituzionalista
No full textThe Author of this paper adds the point of view of the constitutionalist to the debate on the Italian statute n.40/1994 on assisted reproduction illustrated by Flamigni and Mori in their work. The paper ends with a reflection on the recent decision n. 162/2014 issued by the Constitutional Court, which has declared the illegitimacy of the prohibition of heterologous reproduction
L'approvazione della legge Cirinnà : fra riconoscimento dei diritti e scontro ideologico
No full textThe New Italian Law on Civil Unions: Between Rights Recognition and Ideological Clash Abstract: The author examines the coming into force of the first Italian law on civil unions, which, for the first time, grants protection for both homosexual and different sex couples
La Corte costituzionale chiude la porta agli scienziati in nome della dignità dell’embrione
No full textThis essay aims to analize decision no. 84 of 2016 of the Italian Constitu-tional Court, on the matter of scientific research on embryos.
In particular the essay dwells with the problematic acknowledgement of the embryo dignity. The Author considers this aspect in the context of the relation between sci-entific evolution and legislative discretionality, taking into account the other deci-sions of the Court on the matter of medically assisted procreation
A Model for a Linear a-Se Detector in Simulated X-Ray Breast Imaging With Monte Carlo Software
No full textIn-silico clinical trials with digital patient models and simulated devices are an alternative to expensive and long clinical trials on patient population for testing X-ray breast imaging apparatuses. In this work, we simulated a linear-response a-Se detector as an X-ray absorber, neglecting some physical processes, such as electro-hole tracking and thermal noise. In order to tune characteristics of the simulated images toward those of the clinical scanners, the detector response curve, modulation transfer function (MTF), and normalized noise power spectrum (NNPS) were measured on a clinical mammographic unit. The same tests were replicated in-silico via a custom-made Monte Carlo code in order to define a suitable model to modify simulated images and to have realistic pixel values, noise, and spatial resolution. The proposed approach resulted to restore the slope and the magnitude of the NNPS in simulated images toward curves evaluated on a clinical scanner. Similarly, the proposed strategy for tuning noise and spatial resolution in simulated images led to a contrast-to-noise ratio (CNR) evaluated on a custom-made phantom which differed from those in measured images less than 16% in absolute value
Normalized glandular dose coefficients for digital breast tomosynthesis systems with a homogeneous breast model
No full textThis work aims at calculating and releasing tabulated values of dose conversion coefficients, DgNDBT, for mean glandular dose (MGD) estimates in digital breast tomosynthesis (DBT). The DgNDBT coefficients are proposed as unique conversion coefficients for MGD estimates, in place of dose conversion coefficients in mammography (DgNDM or c, g, s triad as proposed in worldwide quality assurance protocols) used together with the T correction factor. DgNDBT is the MGD per unit incident air kerma measured at the breast surface for a 0° projection and the entire tube load used for the scan. The dataset of polyenergetic DgNDBT coefficients was derived via a Monte Carlo software based on the Geant4 toolkit. Dose coefficients were calculated for a grid of values of breast characteristics (breast thickness in the range 20-90 mm and glandular fraction by mass of 1%, 25%, 50%, 75%, 100%) and the simulated geometries, scan protocols, irradiation geometries and typical spectral qualities replicated those of six commercial DBT systems (GE SenoClaire, Hologic Selenia Dimensions, GE Senographe Pristina, Fujifilm Amulet Innovality, Siemens Mammomat Inspiration and IMS Giotto Class). For given breast characteristics, target/filter combination, tube voltage and half value layer (HVL), two spectra with two HVL values have been simulated in order to permit MGD estimates from experimental HVL values via mathematical interpolation from tabulated values. The adopted breast model assumes homogenous composition of glandular and adipose tissues; it includes a 1.45 mm thick skin envelope in place of the 4-5 mm envelope commonly adopted in dosimetry protocols. The simulation code was validated versus AAPM Task group 195 Monte Carlo reference data sets (absolute differences not higher than 1.1%) and by comparison to relative dosimetry measurements with radiochromic film in a PMMA test object (differences within the maximum experimental uncertainty of 11%). The calculated coefficients show maximum relative deviations of -17.6% and +6.1% from those provided by the DBT dose coefficients adopted in the EUREF protocol and of 1.5%, on average, from data in the AAPM TG223 report. A spreadsheet is provided for interpolating the tabulated DgNDBT coefficients for arbitrary values of HVL, compressed breast thickness and glandular fraction, in the corresponding investigated ranges, for each DBT unit modeled in this work
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