Search results for "Lacuna"
showing 10 items of 38 documents
Des fractales pour des villes résilientes et économes
2019
National audience; L’étude des villes dans l’approche de la géographie théorique et quantitative est étroitement liée aux données disponibles pour les décrire : données de population (loi rang-taille, théorie évolutive des villes), données de cartographie des bâtiments (densités, analyses (multi)fractales, pour étudier de quelle manière les bâtiments remplissent l’espace), données de tracés des réseaux de transport. Depuis une dizaine d’années, des données détaillées de localisation d’activités, d’énergie, de transport, de climat, etc. complètent le spectre des applications.En mettant en avant l’articulation entre échelles L’approche fractale s’inscrit dans la logique d’un réductionnisme cl…
Clustering statistics in cosmology
2002
The main tools in cosmology for comparing theoretical models with the observations of the galaxy distribution are statistical. We will review the applications of spatial statistics to the description of the large-scale structure of the universe. Special topics discussed in this talk will be: description of the galaxy samples, selection effects and biases, correlation functions, Fourier analysis, nearest neighbor statistics, Minkowski functionals and structure statistics. Special attention will be devoted to scaling laws and the use of the lacunarity measures in the description of the cosmic texture.
Lacunary Bifurcation of Multiple Solutions of Nonlinear Eigenvalue Problems
1991
In order to describe the type of nonlinear eigenvalue problems we are going to discuss, consider a densely defined closed linear operator T in a real Hilbert space H and let H1 be the Hilbert space which consists of the domain of T together with the graph norm. Also, let H 1 * be the dual space of H1 and denote the dual operator corresponding to T: H1 → H by T’:H → H 1 * . Since H1 is dense in H, we may view H as a subspace of H1, and then the scalar product (·,·) on H and the dual pairing on H1 × H 1 * coincide on H1 × H.
Axial behaviour of Cantor ring diffractals
2003
Cantor ring diffractals describe rotationally symmetric pupils constructed from a one-dimensional polyadic Cantor set. The influence on the axial irradiance of several fractal descriptors of such pupils, including fractal dimension, number of gaps and lacunarity, are investigated. It is shown that, contrary to their transversal response, the axial behaviour of these pupils does not resemble the fractal structure of the aperture. The sensitivity of such pupils to the spherical aberration is also analysed.
Synthesis and Characterization of New Keggin-Based Structure Tungstocobaltates: K9[Co3+W11O39] and its Vanadium Derivatives, K8[Co2+W11V4+O40], K7[Co…
1995
Abstract Good yield synthesis of the potassium salts of four new interrelated : olyoxometalates, [Co3+W11O39]9-(I), [Co2+W11V4+O4]8-(II), [Co2+W11V5+O40]7-(III), and [Co3+W11V5+O40]6-(IV), are reported. The title compounds have been characterized by IR and UV-Vis.-NIR spectroscopies, cyclic voltammetry and magnetic measurements. IR spectra confirm that I has the lacunary structure of an undecatungstate anion, while II through IV have a substituted α-Keggin structure with the vanadium atom located at an octahedral site replacing one tungsten atom. Optical data confirm the oxidation states for both, the Co and V atoms, as formulated for I through IV.
(Di)segni contemporanei
2018
Il contributo intende presentare criticamente alcuni interventi di restauro allineati alla più moderna ed evoluta cultura della conservazione. I due interventi sono compiuti in Sicilia sui resti di due monumenti distrutti dal terremoto che danneggiò la vallata del fiume Belice nel 1968. Il tema della reintegrazione della lacuna nei volumi strutturali degli edifici storici è realizzata attraverso il procedimento per "astrazione volumetrica", con esiti sorprendenti e d'elevata qualità conservativa. The contribution intends to critically present some restoration interventions aligned with the most modern and evolved culture of conservation. The two interventions are carried out in Sicily on th…
A precise stroke classification for evaluation of ischemic stroke subtypes and their relation with diabetes: is TOAST the best?
2010
To The Editor: Regarding the study by Turin et al1 performed to estimate the secular time trends in incidence using a population-based stroke registry in Japan, we discuss some issues of potential interest. First, have the authors classified stroke subtypes according TOAST classification or Oxfordshire classification? No mention has been made in the text concerning the classification methodology of ischemic stroke. It is conceivable that applying the TOAST classification2 of ischemic stroke (a classification with clinical, pathophysiological, anatomic, and instrumental basis that is easily applicable and widely validated) could provide a more precise selection of patients with lacunar strok…
Diabetic and non-diabetic subjects with ischemic stroke: Differences, subtype distribution and outcome
2008
Abstract Background and aim Diabetes mellitus increases the risk of stroke, and pathophysiological changes of diabetic cerebral vessels may differ in comparison with non-diabetic ones; nonetheless, the clinical and prognostic profile of stroke in diabetic patients is not yet fully understood. On this basis, the aim of our study was to evaluate cerebrovascular risk factor prevalence in diabetic stroke patients in comparison with non-diabetics, to analyze whether diabetics have a different prevalence of stroke subtypes as classified by the TOAST classification, and determine whether diabetics and non-diabetics have a different prognosis. Methods and results We enrolled 102 diabetics and 204 n…
On the Almost Everywhere Convergence of Multiple Fourier-Haar Series
2019
The paper deals with the question of convergence of multiple Fourier-Haar series with partial sums taken over homothetic copies of a given convex bounded set $$W\subset\mathbb{R}_+^n$$ containing the intersection of some neighborhood of the origin with $$\mathbb{R}_+^n$$ . It is proved that for this type sets W with symmetric structure it is guaranteed almost everywhere convergence of Fourier-Haar series of any function from the class L(ln+L)n−1.
Dysarthria in acute ischemic stroke: lesion topography, clinicoradiologic correlation, and etiology.
2001
Background and purpose: Although dysarthria is a frequent symptom in cerebral ischemia, there is little information on its anatomic specificity, spectrum of associated clinical characteristics, and etiologic mechanisms. Methods: An investigation of 68 consecutive patients with sudden onset of dysarthria due to a single infarction confirmed by MRI or CT was conducted. Results: Dysarthria was associated with a classic lacunar stroke syndrome in 52.9% of patients. Isolated dysarthria and dysarthria–central facial and lingual paresis occurred in 2.9% (n = 2) and 10.3% (n = 7), respectively. Dysarthria–clumsy hand syndrome was observed in 11.7% (n = 8) of patients and associated with pure motor …