Search results for "Lacuna"
showing 10 items of 38 documents
Vascular Risk Factors, Vascular Diseases, and Imaging Findings in a Hospital-based Cohort of Mild Cognitive Impairment Types
2017
Background: Mild Cognitive Impairment (MCI) is a transitional state between normal cognition and dementia. Objective: The aim of this study is to investigate the role of vascular risk factors, vascular diseases, cerebrovascular disease and brain atrophy in a large hospital-based cohort of MCI types including 471 amnestic MCI (a-MCI), 693 amnestic MCI multiple domain (a-MCImd), 322 single non-memory MCI (snm-MCI), and 202 non amnestic MCI multiple domain (na-MCImd). For comparison, 1,005 neurologically and cognitively healthy subjects were also evaluated. Method: Several vascular risk factors and vascular diseases were assessed. All participants underwent neurological, neuropsychological an…
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 …
Synthesis, Characterization, and Catalysis of β3-[(CoIIO4)W11O31(O2)4],10- the First Keggin-Based True Heteropoly Dioxygen (Peroxo) Anion. Spectrosco…
1999
Reactions of hydrogen peroxide with several lacunary polyoxometalates of the 1:11 series, XW11O39m- (X = Co3+, Ga3+, Fe3+, Si4+, and P5+), are reported. Synthetic pathways to new polyoxotungstates incorporating dioxygen moieties (peroxo and/or superoxo) are developed. The key step involves treating lacunary precursors with H2O2 in strongly buffered aqueous solutions. Upon reaction of H2O2 with α-[Co3+W11O39],9- (a) the central tetrahedral Co3+ is reduced to Co2+ and (b) each of the four unshared oxygens surrounding the vacancy are replaced by a peroxide group, yielding salts of the tetraperoxide anion β3-[(Co2+O4)W11O31(O2)4]10- (1). These results are unequivocally established by a combinat…
On lacunary Toeplitz determinants
2014
By using Riemann--Hilbert problem based techniques, we obtain the asymptotic expansion of lacunary Toeplitz determinants $\det_N\big[ c_{\ell_a-m_b}[f] \big]$ generated by holomorhpic symbols, where $\ell_a=a$ (resp. $m_b=b$) except for a finite subset of indices $a=h_1,\dots, h_n$ (resp. $b=t_1,\dots, t_r$). In addition to the usual Szeg\"{o} asymptotics, our answer involves a determinant of size $n+r$.
Statistical geometric affinity in human brain electric activity
2007
10 pages, 9 figures.-- PACS nrs.: 87.19.La; 05.45.Tp.-- ISI Article Identifier: 000246890100105
Diffraction by fractal metallic supergratings.
2007
The reflectance of corrugated surfaces with a fractal distribution of grooves is investigated. Triadic and polyadic Cantor fractal distributions are considered, and the reflected intensity is compared with that of the corresponding periodic structure. The self-similarity property of the response is analyzed when varying the depth of the grooves and the lacunarity parameter. The results confirm that the response is self-similar for the whole range of depths considered, and this property is also maintained for all values of the lacunarity parameter. © 2007 Optical Society of America. Fil: Skigin, Diana Carina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación…
Fractal zone plates with variable lacunarity.
2009
Fractal zone plates (FZPs), i.e., zone plates with fractal structure, have been recently introduced in optics. These zone plates are distinguished by the fractal focusing structure they provide along the optical axis. In this paper we study the effects on this axial response of an important descriptor of fractals: the lacunarity. It is shown that this parameter drastically affects the profile of the irradiance response along the optical axis. In spite of this fact, the axial behavior always has the self-similarity characteristics of the FZP itself.
Secundo y la gran laguna en el Dialogus de oratoribus
2004
Jorge.Tarrega@uv.es El artículo examina un problema puntual en el polémico Dialogus de oratoribus: la cuestión de la gran laguna entre los capítulos 35 y 36. El autor del estudio expone una perspectiva histórica de los principales argumentos esgrimidos por la investigación sobre este asunto a lo largo, especialmente, del siglo XX. Para determinar la extensión y el contenido de la parte perdida, el análisis se estructura en torno a dos ejes: 1) la tradición manuscrita; y 2) la comparación entre el opúsculo y otros diálogos. The paper examines a specific problem in the controversial Dialogus de oratoribus: the issue of the great lacuna between chapters 35 and 36. The author of the article pla…
Adam Smith on Monopoly Theory. Making good a lacuna
2014
This article analyses Adam Smith's views on monopoly by focusing on Book IV and V of The Wealth of Nations. It argues that the majority of scholars have assessed Smith's analysis of monopoly starting from premises different from those, actually though implicitly, used by Smith. We show that Smith makes use of the word 'monopoly' to refer to a heterogeneous collection of market outcomes, besides that of a single seller market, and that Smith's account of monopolists' behaviour is richer than that provided by later theorists. We also show that Smith was aware of the growth-retarding effect of monopoly and urged State regulation. © 2014 Scottish Economic Society.