324,638 research outputs found
Accurate length determination of DNA molecules visualized by Atomic Force Microscopy: evidence for a partial B- to A-form transition on mica
No full textPOSITIVE RADIAL SOLUTIONS OF THE DIRICHLET PROBLEM FOR THE MINKOWSKI-CURVATURE EQUATION IN A BALL
No full textWe study the existence and multiplicity of positive radial solutions of the Dirichlet problem for the Minkowski-curvature equation
where is a ball in (). According to the behaviour of near , we prove the existence of either one, two or three positive solutions. All results are obtained by reduction to an equivalent non-singular one-dimensional problem, to which variational methods can be applied in a standard way
Review of Detectors Available for Full-Field Digital Mammography
No full textRadiation Detectors for Medical Imaging discusses the current state of the art and future prospects of photon-counting detectors for medical imaging applications. Featuring contributions from leading experts and pioneers in their respective fields, this book:
- Describes x-ray spectral imaging detectors based on cadmium zinc telluride (CdZnTe) and cadmium telluride (CdTe) materials
- Presents novel computed tomography (CT) and x-ray clinical applications of photon-counting detectors
- Considers the future use of CT scanners as both an anatomical and a functional modality in areas typically reserved for nuclear medicine techniques
- Addresses pulse pileup, incomplete charge collection, and other phenomena that can degrade the spectral response of photon-counting detectors
- Examines silicon photomultipliers used in single-photon emission computed tomography (SPECT) and positron emission tomography (PET) system
La Convenzione tra la Santa Sede e l'Italia in materia di scambio di informazioni tributarie, in Riv. Il Tributario, Milano, Giuffrè (ISSN 2465-2512)
No full textLa recente approvazione della legge di “ratifica ed esecuzione della Convenzione tra il Governo della Repubblica italiana e la Santa Sede in materia fiscale” (28 giugno 2016) si inserisce nell’ambito di un sistematico impegno internazionale della S. Sede e dell’Italia, di svolgere un ruolo di garanzia, nel contesto della globalizzazione economica dei mercati, con particolare riferimento ai settori della trasparenza, della vigilanza e dell’informazione finanziaria. Si fonda sulla consapevolezza (reciproca) che le dinamiche di contrasto nel campo delle attività finanziarie, legate a fenomeni di elusione o evasione fiscale (ma anche quelli di riciclaggio, competizione fiscale dannosa, ecc.), sono “realizzabili esclusivamente attraverso un efficiente scambio di informazioni nell’ambito della cooperazione amministrativa tra Stati”
On the lower and upper solution method for the prescribed mean curvature equation in Minkowski space
No full textWe develop a lower and upper solution method for the Dirichlet problem associated with the prescribed mean curvature equation in Minkowski space {-div(∇u/√1-|∇u|2=f(x,u) in Ω u=0 on ∂Ω Here Ω is a bounded regular domain in RNand the function f satisfies the Carathéodory conditions. The obtained results display various peculiarities due to the special features of the involved differential operator
Evaluating the Performance of Digital Mammography Systems: Physical and Psychophysical Characterization
No full textThis chapter illustrates some of the methods used for evaluating the physical and psychophysical performances of digital detector for imaging in mammography. Objective and subjective measurements by means of human observers and automatic methods can be achieved to better characterize the performance of digital systems. Some results from commercial units are also presented. To assess the image quality of the various systems, spatial resolution and noise properties can be evaluated using metrics such as the modulation transfer function (MTF), noise power spectra (NPS), noise-equivalent quanta (NEQ), and detective quantum efficiency (DQE). While the image quality of different systems can be characterized by using these objective measures, medical diagnosis also involves perception of the observer. Since an image is, by definition, a means for visually representing the clinical information captured by the equipment, at some stage quality must be based on the judgment of a human observer. A more direct image-based method of evaluating overall system performance is by using contrast detail (CD) phantoms. These phantoms contain test objects of different size and contrast and are traditionally used to determine the boundary between visible and invisible objects represented by the imaging system. An issue with this type of experiment is that subjective observation can often result in relatively high inter- and intra-observer variability. A high-quality image is of major importance to assure an accurate diagnosis, and this is generally determined by three primary physical image-quality parameters: contrast, spatial resolution, and noise. These quality parameters can be evaluated by objective image-quality measurements such as signal-to-noise ratio (SNR), MTF, and NPS. Together they form a basis for the description of image quality that encompasses the three primary physical image-quality parameters. These factors contribute to the measurement of DQE, which has been well established as the most suitable parameter for describing the imaging performance of an x-ray digital imaging device. DQE is the measurement of the combined effects of the noise and contrast performance of an imaging system, expressed as a function of object detail. Parameters such as NEQ and DQE have the potential for providing objective assessments of imaging performance for an image viewed by an ideal observer. Measurements of this type allow objective comparisons to be made between different systems. More research is required to establish mathematical relationships between these measures of performance and the requirements for clinical examinations. Some studies have investigated the relationship between physical performance characteristics (MTF, NPS, and DQE), and psychophysical performance (such as those derived from CD analysis). The relationship between the results of physical measurements, phantom evaluations, and clinical performance is not fully understood. Object detectability could be directly linked to DQE, although the response of the human eye, system noise, and variation of the DQE as a function of the exposure need to be taken into account. Image quality can be evaluated by combining the physical characteristics of the imaging system, overall system performance, and observer performance studies
How are knowledge acquisition and SMEs' internationalization related? Empirical evidence from Gruppo Germani
No full textDiffusive author(s), cohesive author: Analysis of S/N (1994)
No full textThis study indicates the ways in which various aspects of the author(s) are brought forth in Dumb type’s performance art, the S/N production. Previous research has suggested a non-hierarchical organization of Dumb type and the absence of a “privileged author” in Dumb type’s collaborative work, S/N. However, the results that I have investigated from member’s interviews on the creative process of S/N along with my analysis of the recorded images of S/N, indicate a different aspect of the author(s). First, S/N was created through, so to speak, the collective ideas of the members of Dumb type. Further, S/N has at least nine quotations from previous performances, installations, and printed writings, besides the work-in-progress technique. Explicating one of the “author functions” as given by Michel Foucault, each text has plural subjects of the author. However, it has been revealed from members’ interviews that Teiji Furuhashi had a decision-making role in selecting the members’ ideas within the performance. Since then, S/N has had plural subjects of creation; however, Furuhashi is one of the subjects of creation along with the “privileged author.” S/N has plural authors (diffusive authors) yet at the same time, it has a “privileged author,” Teiji Furuhashi (cohesive author)
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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