Search results for "Compact"
showing 10 items of 531 documents
Eigenvectors of k-psi-contractive wedge operators
2008
We present new boundary conditions under which the fixed point index of a strict-$\psi$-contractive wedge operator is zero. Then we investigate eigenvalues and corresponding eigenvectors of k-$\psi$-contractive wedge operators.
Representation of quasi-measure by a Henstock-Kurzweil type integral on a compact zero-dimensional metric space
2009
A derivation basis is introduced in a compact zero-dimensional metric space X. A Henstock-Kurzweil type integral with respect to this basis is defined and used to represent the so-called quasi-measure on X.
On some parameters related to weak noncompactness in L1(μ,E)
2009
A measure of weak noncompactness γU is defined in a Banach space X in terms of convex compactness. We obtain relationships between the measure γU(A) of a bounded set A in the Bochner space L1(μ,E) and two parameters Π(A) and Λ1(A) related, respectively, to uniform integrability and weak-tightness. The criterion for relative weak compactness in L1(μ,E) is recovered.
Left ventricular non compaction: epidemiology, clinical findings, diagnosis and therapy
2014
Abstract Left ventricular non compaction (LVNC) is a cardiomyopathy due to an arrest of the normal development of myocardium which determines the persistence of foetal myocardium in post--natal life in at least 2/3 of the wall (criterion known as non compacted/ compacted ratio greater than 2). Although in absence of a confirmed prevalence of LVNC, reviewing literature shows an increasing number of reports over the years, though diagnosed cases represent just the tip of a realistically far wider phenomenon. Clinical manifestations are variable, ranging from the absence of any symptom to congestive heart failure, arrhythmias and systemic thromboembolism. Echocardiography is the gold standard …
On the hydro-mechanical behaviour of remoulded and natural Opalinus Clay shale
2016
The geo-energy sector makes use of advanced technologies such as shale gas extraction, CO2 sequestration and nuclear waste geological disposal that rely on the exploitation of shale formations. Due to the great depths involved in these applications and the difficulties in retrieving intact samples, remoulded shale specimens are often adopted for hydro-mechanical testing. Remoulded and intact shales may substantially differ in their hydro-mechanical behaviour due to the particular structure of the natural material, which is the result of diagenesis and burial history. This paper presents an experimental campaign aimed at (i) characterizing the role of diagenesis and depth for Opalinus Clay s…
The monodromy groups of Dolgachev's CY moduli spaces are Zariski dense
2014
Let $\mathcal{M}_{n,2n+2}$ be the coarse moduli space of CY manifolds arising from a crepant resolution of double covers of $\mathbb{P}^n$ branched along $2n+2$ hyperplanes in general position. We show that the monodromy group of a good family for $\mathcal{M}_{n,2n+2}$ is Zariski dense in the corresponding symplectic or orthogonal group if $n\geq 3$. In particular, the period map does not give a uniformization of any partial compactification of the coarse moduli space as a Shimura variety whenever $n\geq 3$. This disproves a conjecture of Dolgachev. As a consequence, the fundamental group of the coarse moduli space of $m$ ordered points in $\mathbb{P}^n$ is shown to be large once it is not…
Bending Instability of an Accretion Disc Around a Black Hole
2001
We demonstrate that generically an accretion disk around a compact object could have a new type of instability in that the accretion flow need not be symmetric with respect to the equatorial plane even when matter is supplied symmetrically farther out. We find that this behaviour is mainly due to interaction of outgoing matter bounced off the centrifugal barrier and the incoming accretion. We believe that X-ray variability could be developed by this instability.
3D simulations of microquasar jets in clumpy stellar winds
2011
High-mass microquasars consist of a massive star and a compact object, the latter producing jets that will interact with the stellar wind. The evolution of the jets, and ultimately their radiative outcome, could depend strongly on the inhomogeneity of the wind, which calls for a detailed study. The hydrodynamics of the interaction between a jet and a clumpy wind is studied, focusing on the global wind and single clump-jet interplay. We have performed, using the code \textit{Ratpenat}, three-dimensional numerical simulations of a clumpy wind interacting with a mildly relativistic jet, and of individual clumps penetrating into a jet. For typical wind and jet velocities, filling factors of abo…
Calcestruzzo autocompattante siciliano: un'esperienza con il filler vulcanico dell'Etna
2009
Self compacting concrete is one of the last developments in the technology of concrete, being studied and improved from the first '70es. Its production is connected with the use of fillers, most of which coming from iron metallurgy, scarsely present on Sicilian territory. So, the aim of the risearch was to realize self compacting concrete using exclusively local filler, particularly the Etna ashes with a strong pozzolanic connotation, pointing out the use of useless at the moment natural resource. The study relates to the verification of the more appropriate mix-designs and the tests on compressive strength of specimens to early curing and after 28 days. Different characterization tests wer…
Inner Edge Drag by an Asynchronous Primary and Accretion Disc Structure In Close Binaries
1996
In this work a 3-D ‘Smoothed Particle Hydrodynamics’ ([1]; [4]; [5]) accretion disc is simulated where particles at its inner edge are dragged by a fast spinning compact central star, as in the case of the intermediate polars. The angular velocity of the central star is twice the orbital angular velocity w 0. This drag can be attributed mainly to viscous interaction in the dense compact star atmosphere, although magnetic coupling may also play a role.