4,477 research outputs found
An automated system for lung nodule detection in low-dose computed tomography
A computer-aided detection (CAD) system for the identification of pulmonary
nodules in low-dose multi-detector helical Computed Tomography (CT) images was
developed in the framework of the MAGIC-5 Italian project. One of the main
goals of this project is to build a distributed database of lung CT scans in
order to enable automated image analysis through a data and cpu GRID
infrastructure. The basic modules of our lung-CAD system, a dot-enhancement
filter for nodule candidate selection and a neural classifier for
false-positive finding reduction, are described. The system was designed and
tested for both internal and sub-pleural nodules. The results obtained on the
collected database of low-dose thin-slice CT scans are shown in terms of free
response receiver operating characteristic (FROC) curves and discussed.Comment: 9 pages, 9 figures; Proceedings of the SPIE Medical Imaging
Conference, 17-22 February 2007, San Diego, California, USA, Vol. 6514,
65143
Development of a new screening tool for cyber pornography. Psychometric properties of the Cyber Pornography Addiction Test (CYPAT)
Objective: Internet pornography addiction typically involves viewing, downloading and trading online pornography or engagement in adult fantasy role-play. There are some well-validated inventories measuring perceived addiction to internet pornography but these instruments are often too long for a functionally use and fast scoring. The aim of this study was to evaluate the psychometric properties of the cyber pornography addiction test (CYPAT), a new, brief, screening measure for assessing cyber pornography.Method: Participants of this study completed the CYPAT, the CPUI, the TAS-20 and the FACES-IV. Descriptive statistics were calculated and Exploratory Factor Analysis (EFA) and Confirmatory Factor Analysis (CFA) were applied.Results: Cronbach's alpha coefficient suggested excellent reliability of the measure. Results of this study revealed also good construct, convergent and divergent validity.Conclusions: CYPAT is a brief self-report screening scale composed of 11 items scored on a five-point Likert scale with good psychometrics properties. The implications of these findings for future theoretical and empirical research in this field are discusse
Computer-aided detection of pulmonary nodules in low-dose CT
A computer-aided detection (CAD) system for the identification of pulmonary
nodules in low-dose multi-detector helical CT images with 1.25 mm slice
thickness is being developed in the framework of the INFN-supported MAGIC-5
Italian project. The basic modules of our lung-CAD system, a dot enhancement
filter for nodule candidate selection and a voxel-based neural classifier for
false-positive finding reduction, are described. Preliminary results obtained
on the so-far collected database of lung CT scans are discussed.Comment: 3 pages, 4 figures; Proceedings of the CompIMAGE - International
Symposium on Computational Modelling of Objects Represented in Images:
Fundamentals, Methods and Applications, 20-21 Oct. 2006, Coimbra, Portuga
New contributions to the absolute chronology at the Early Eneolithic cultures in the central Balkans.
In this study we present new absolute dates for the Early Eneolithic in Serbia. Four of them confirm the recently
obtained dates from that period (Bubanj-Hum I culture) but two samples (from Mokranjske stene and Bubanj) provide somewhat
later dates for this period, although their stratigraphic context makes their interpretation difficult. Pottery from those sites,
besides the typical examples, also shows particular stylistic and typological characteristics that resemble Galatin or Sãlcuþa IV
cultures, so one can presume that the Bubanj-Hum I culture in Serbia may have lasted longer than what is generally assumed
New absolute dates as a contribution to the study of the Late Bronze Age Chronology in the Central Balkans
The paper presents three Late Bronze Age absolute dates from contexts located
in the territory of western Serbia and northern Republic of Macedonia, and discusses
them together with further absolute dates from the same period, which will be published
shortly by one of the authors and other colleagues. On the basis of these dates the Late
Bronze Age chronology is discussed together with cultural aspects of the groups representative of this period in the Central Balkans
Search for Higgs Bosons in SUSY Cascade Decays and Neutralino Dark Matter
The Minimal Supersymmetric Extension of the Standard Model (MSSM) is a well
motivated theoretical framework, which contains an extended Higgs sector,
including a light Higgs with Standard Model-like properties in most of the
parameter space. Due to the large QCD background, searches for such a Higgs,
decaying into a pair of bottom quarks, is very challenging at the LHC. It has
been long realized that the situation may be ameliorated by searching for Higgs
bosons in supersymmetric decay chains. Moreover, it has been recently suggested
that the bobber decay channel may be observed in standard production channels
by selecting boosted Higgs bosons, which may be easily identified from the QCD
background. Such boosted Higgs bosons are frequent in the MSSM, since they are
produced from decays of heavy colored supersymmetric particles. Previous works
have emphasized the possibility of observing boosted Higgs bosons in the light
higgsino region. In this work, we study the same question in the regions of
parameter space consistent with a neutralino dark matter relic density,
analyzing its dependence on the non-standard Higgs boson, slepton and squark
masses, as well as on the condition of gaugino mass unification. In general, we
conclude that, provided sleptons are heavier than the second lightest
neutralinos, the presence of boosted Higgs is a common MSSM feature, implying
excellent prospects for observation of the light MSSM Higgs boson in the near
future.Comment: 30 pages, 9 figures. v2: New Xenon 100 results implemented, version
to appear in PR
Density functional theory for strongly-correlated bosonic and fermionic ultracold dipolar and ionic gases
We introduce a density functional formalism to study the ground-state
properties of strongly-correlated dipolar and ionic ultracold bosonic and
fermionic gases, based on the self-consistent combination of the weak and the
strong coupling limits. Contrary to conventional density functional approaches,
our formalism does not require a previous calculation of the interacting
homogeneous gas, and it is thus very suitable to treat systems with tunable
long-range interactions. Due to its asymptotic exactness in the regime of
strong correlation, the formalism works for systems in which standard
mean-field theories fail.Comment: 5 pages, 2 figure
Pressure shock fronts formed by ultra-fast shear cracks in viscoelastic materials
Spontaneously propagating cracks in solids emit both pressure and shear waves. When a shear crack propagates faster than the shear wave speed of the material, the coalescence of the shear wavelets emitted by the near-crack-tip region forms a shock front that significantly concentrates particle motion. Such a shock front should not be possible for pressure waves, because cracks should not be able to exceed the pressure wave speed in isotropic linear-elastic solids. In this study, we present full-field experimental measurements of dynamic shear cracks in viscoelastic polymers that result in the formation of a pressure shock front, in addition to the shear one. The apparent violation of classic theories is explained by the strain-rate-dependent material behavior of polymers, where the crack speed remains below the highest pressure wave speed prevailing locally around the crack tip. These findings have important implications for the physics and dynamics of shear cracks such as earthquakes
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