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OALib Journal期刊

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匹配条件: “ Umberto Pignatelli” ,找到相关结果约815条。
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Papillary Carcinoma Arising in Thyroglossal Duct Cyst: A Retrospective Analysis (Cancer of the Thyroid or Primary Cancer of the Thyroglossal Cyst)  [PDF]
Paolo Gamba, Umberto Pignatelli, Giampiero D’Addazio, Gabriella Licursi, Luca Gentile, Ugo Moz
Open Access Library Journal (OALib Journal) , 2018, DOI: 10.4236/oalib.1104259
Abstract:
Thyroglossal duct cysts are one of the most common congenital abnormalities of the cervical region. Complications of these swellings are rare, and among these, appearance of a carcinoma has also been noted. Thyroglossal duct cyst carcinoma (TGDC) is a rare entity and its management is controversial. The incidence of thyroid papillary carcinoma in thyroglossal duct cyst is less than 1%, in most cases, the diagnosis is made postoperatively. We report the case of an adult female patient with a papillary carcinoma arising in a thyroglossal duct cyst. Our aim is defining a clinical protocol to diagnose the thyreoglossal duct carcinoma through clinical features, radiological investigations, cytological and histopathological examinations and, through this diagnostic protocol, to choose the best surgical approach. The literature contains 300 cases of this pathology; papillary histotype constitutes about 80%, then squamocellular carcinoma, mixed folliculo-papillary carcinoma and adenocarcinoma follow. The literature suggests two different hypotheses: neoplasia originating from ectopic thyroid tissue and plurifocal theory. The adopted diagnostic investigations are: ultrasonography, Fine Needle Aspiration Biopsy (FNAB), Magnetic Resonance Imaging (MRI). Our patient was treated using a modified Sistrunk’s procedure operation, in which thyroidectomy proved crucial for the correct diagnosis and continuation of appropriate treatment. Our case confirms the difficulty in distinguishing a primitive thyroglossal duct carcinoma from a synchronous metastatic papillary carcinoma of the thyroid. This dilemma often remains unresolved. The two different surgical approaches reported in the literature, one more conservative and the other more aggressive, apparently alternatives are instead complementary and adequate when strict diagnostic criteria and adequate follow-up, are observed. The first year follow-up includes the thyroglobulin level determination and a neck ecografic scan every 3 months. The patient has been following for two years without any metastasis.
A Massive Dark Object in the S0 galaxy NGC 4350
E. Pignatelli
Physics , 2000,
Abstract: We present a new detection of a Massive Dark Object in the S0 Galaxy NGC 4350, obtained applying a new dynamical model on ground-based photometric and kinematic data already present in literature.
Multi-component models for disk galaxies. A test case on NGC 5866
E. Pignatelli
Physics , 1999,
Abstract: We present an application of a new set of detailed, self-consistent, dynamical models for disc galaxies. We start from the hypothesis that each galaxy can be decomposed in a bulge, following the r^{1/4} law, and a disc with an exponential projected density profile; and that the isodensity surfaces of each component can be represented by similar concentric spheroids. After taking into account both the asymmetric drift effects and the integration along the line of sight, we produce the rotational velocity and velocity dispersion profile,_and_ the approximate shape of the line of sight velocity distributions for the stars as parameterized by the h3 and h4 coefficients of the Gauss-Hermite expansion of the line profile. Photometric and kinematical data have been taken from the literature for the test case of the S0 galaxy NGC 5866, for which detailed stellar kinematical data are available at different positions across the galaxy. Apart from the very inner, dust-obscured regions of the galaxy, where observational effects are likely to be dominant, the model successfully reproduce the whole set of dynamical data available as well as giving a good fit to the photometry. The galaxy is shown to have an isotropic velocity dispersion tensor, thus giving a hint on a dissipational formation process.
Some (big) irreducible components of the moduli space of minimal surfaces of general type with $p_g=q=1$ and $K^2=4$
Roberto Pignatelli
Mathematics , 2008,
Abstract: In this paper we study the minimal surfaces of general type with $p_g=q=1$ and $K^2=4$ whose Albanese general fibre has genus 2, classifying those such that the direct image (under the Albanese morphism) of the bicanonical sheaf is sum of line bundles. We find 8 unirational families, all of dimension strictly bigger than the expected one. These families are pairwise disjoint irreducible components of the moduli space of minimal surfaces of general type.
On surfaces with a canonical pencil
Roberto Pignatelli
Mathematics , 2009,
Abstract: We classify the minimal surfaces of general type with $K^2 \leq 4\chi-8$ whose canonical map is composed with a pencil, up to a finite number of families. More precisely we prove that there is exactly one irreducible family for each value of $\chi \gg 0$, $4\chi-10 \leq K^2 \leq 4\chi-8$. All these surfaces are complete intersections in a toric $4-$fold and bidouble covers of Hirzebruch surfaces. The surfaces with $K^2=4\chi-8$ were previously constructed by Catanese as bidouble covers of $\PP^1 \times \PP^1$.
Riemann surfaces with a quasi large abelian group of automorphisms
Roberto Pignatelli,Carmen Raso
Le Matematiche , 2011,
Abstract: In this work we classify all Riemann surfaces having a quasi large abelian group of automorphisms, i.e. having an abelian group of automorphisms of order strictly bigger than 2(g 1), where g denotes the genus of the Riemann surface.
Dynamical Models Of S0 And Sa Galaxies
Ezio Pignatelli,Giuseppe Galletta
Physics , 1996,
Abstract: We present a set of detailed, self-consistent, isotropic dynamical models for disc galaxies. We start from the hypothesis that each galaxy can be decomposed in a bulge, following the r^{1/4} law, and a disc with an exponential projected density profile; and that the isodensity surfaces of each component can be represented by similar concentric spheroids. Under these conditions we produce the rotational velocity and velocity dispersion profiles, after taking into account both the asymmetric drift effects and the integration along the line of sight. The model is successfully applied to reproduce the stellar kinematic and photometry of the bulge of the 4 lenticular and early-type spiral galaxies NGC 4565, NGC 7814, NGC 5866 and NGC 4594. For these galaxies detailed stellar kinematical data are available at different positions across the galaxy. The application of our models shows that: 1) For all the galaxies considered in this work, an isotropic model is able to reproduce the whole dynamical data. This is surprising in the special case of NGC 4565, for which previous models were unable to reproduce the velocity distribution without introducing strong anisotropies. 2) We do not need a dark mass halo to reproduce these data. This do not mean that a dark halo is not present, but just that its dynamical effects in these inner regions of the galaxies are negligible.
Multi-component models for disk galaxies. I. Stellar rotation and anisotropy
E. Pignatelli,G. Galletta
Physics , 1997,
Abstract: We present here a self-consistent, tridimensional model of a disc galaxy composed by a number of ellipsoidal distributions of matter having different flattening and density profile. The model is self-consistent and takes into account the observed luminosity distribution, the flattening profile and the stellar rotation- and velocity dispersion- curves. In this paper we considered the particular case of a disc galaxy composed by two spheroidal bodies: an exponential disc and a bulge following the r^{1/4} law. We studied the behavior of the stellar rotation- and velocity dispersion- profiles along the sequence of S0s and Spirals, identified by an increasing disc-to-bulge ratio. Inside every class, kinematic curves were produced by changing the relative concentration of the two components and the inclination of the galaxy with respect to the line of sight. The comparison with observational data requires only two scaling factors: the total mass of the galaxy, and the effective radius. The model allows also to detect the presence of anisotropy in the velocity distribution. In the special case of S0s, we explored the sensitivity of the kinematics of the model by changing the anisotropy and the flattening of the bulge. For intermediate flattening (0.4
Anatomy of giant spiral galaxies
E. Pignatelli,G. Galletta
Physics , 2000,
Abstract: We present B and I band photometry, gas and star kinematics and 3D modelling of 7 giant spiral galaxies. The stellar systems studied have morphological types spanning from S0/a to Sc and absolute magnitudes from -20.6 to -22.5. The spectra have been collected with the spectrographs Boller & Chivens and EFOSC2 of the 2.2m ESO-MPI telescope. Images have been taken with the same telescope. The models fit simultaneously the photometric and kinematics data using a disk+bulge tridimensional model. The distribution of luminous matter, coming from the fit of the photometric data is compared with the distribution of total matter derived from the velocity dispersion and velocity curves. The intrinsic properties of these galaxies, such as the disk/bulge mass ratio, the total mass and the scale length of the galaxy components are presented and discussed.
Morphological classification of high redshift galaxies
E. Pignatelli,G. Fasano
Physics , 2000,
Abstract: We present GASPHOT, a tool for automated surface photometry and morphological classification of galaxies in deep and wide fields. The requirements for any such tool are reviewed, and its use for the classification of high-z galaxies is presented. In the case if HDF-like images, for galaxies having a magnitude ranging from 24 to 27.5, the uncertainties on the photometric parameters derived from GASPHOT are respectively 0.02-0.1 on magnitude, 0.03 on the logarithm of the scale length, 0.02-0.5 on the Sersic index n used to classify the surface brightness profile of the galaxies. A comparison with the results achieved using Sextractor is presented.
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