1,721,260 research outputs found
Step-Wise Increasing Surgical Complexity in Single-Stage Treatment of Gallbladder and Bile Duct Stones
No full textOn a sum of squares operator related to the Schrödinger equation with a magnetic field
No full textWe study the analytic and Gevrey regularity for a “sum of squares” operator closely connected to the Schrödinger equation with minimal coupling. We however assume that the (magnetic) vector potential has some degree of homogeneity and that the Hörmander bracket condition is satisfied. It is shown that the local analytic/Gevrey regularity of the solution is related to the multiplicities of the zeroes of the Lie bracket of the vector fields
Gevrey regularity for a class of sums of squares of monomial vector fields
Full text linkAnalytic or Gevrey hypoellipticity is proved for a class of sums of squares of vector fields having a symplectic characteristic manifold of dimension 2 and arbitrary (even) codimension. We note that this class contains examples for which the Treves stratification seems to work as well as examples for which the Treves stratification does not identify properly the non symplectic stratum
ANALYTIC HYPOELLIPTICITY for SUMS of SQUARES in the PRESENCE of SYMPLECTIC NON TREVES STRATA
Full text linkIn Albano, Bove and Mughetti [J. Funct. Anal. 274(10) (2018), 2725-2753]; Bove and Mughetti [Anal. PDE 10(7) (2017), 1613-1635] it was shown that Treves conjecture for the real analytic hypoellipticity of sums of squares operators does not hold. Models were proposed where the critical points causing a non-analytic regularity might be interpreted as strata. We stress that up to now there is no notion of stratum which could replace the original Treves stratum. In the proposed models such 'strata' were non-symplectic analytic submanifolds of the characteristic variety. In this note we modify one of those models in such a way that the critical points are a symplectic submanifold of the characteristic variety while still not being a Treves stratum. We show that the operator is analytic hypoelliptic
The daily diary and the questionnaire are not equivalent for the evaluation of bowel habits
Full text linkCOLLABORATOR ITALIAN CONSTIPATION STUDY GROUP:
Bellini M, Biagi S, Costa F, De Bortoli N, Gambaccini D, Mammini C, Mumolo MG, Ricchiuti A, Marchi S, Bove A, Balzano A, Sormani MP, Bruzzi P, Battaglia E, Niola P, Verna C, Grassini M, Bocchini R, Cimatti M, Fornasari L, Montaletti I, Pazzi P, Alduini P, Berni I, Ceccarelli G, Bassotti G, Corazzi N, Morozzi B, Viegas LB, Pucciani F, Giani I, Ringressi N
Definizione di metodologie operative per la caratterizzazione e la differenziazione dei corpi idrici sotterranei
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
The ship model basin of Naples' University Federico II: Facilities, experimental tests, measurement systems
Full text linkThis work presents the main facilities of the Naples Towing Tank, LEIN: the instruments and the potential of the laboratory are presented, highlighting some strategies to resolve critical points typical of the towing tank tests. As example we point the attention on three aspects, typically critical: towing point of planing vessels, the accuracy of wave spectra generation and the settings of the radii of gyration for the seakeeping models
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