1,093 research outputs found

    One and two dimensional tunnel junction arrays in weak Coulomb blockade regime-absolute accuracy in thermometry

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    We have investigated one and two dimensional (1D and 2D) arrays of tunnel junctions in partial Coulomb blockade regime. The absolute accuracy of the Coulomb blockade thermometer is influenced by the external impedance of the array, which is not the same in the different topologies of 1D and 2D arrays. We demonstrate, both by experiment and by theoretical calculations in simple geometries, that the 1D structures are better in this respect. Yet in both 1D and 2D, the influence of the environment can be made arbitrarily small by making the array sufficiently large.Comment: 11 pages, 3 figure

    Canonical analysis based on scatter matrices.

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    In this paper, the influence functions and limiting distributions of the canonical correlations and coefficients based on affine equivariant scatter matrices are developed for elliptically symmetric distributions. General formulas for limiting variances and covariances of the canonical correlations and canonical vectors based on scatter matrices are obtained. Also the use of the so called shape matrices in canonical analysis is investigated. The scatter and shape matrices based on the affine equivariant Sign Covariance Matrix as well as the Tyler's shape matrix are considered in more detail. Their finite sample and limiting efficiencies are compared to those of the Minimum Covariance Determinant estimator and S-estimates through theoretical and simulation studies. The theory is illustrated by an example.Canonical correlations; Canonical variables; Canonical vectors; Covariance; Covariance determinant estimator; Determinant estimator; Distribution; Efficiency; Estimator; Functions; Influence function; Matrix; Scatter; Shape matrix; Sign covariance mix; Simulation; Studies; Theory; Tyler's estimate;

    Xanthogranulomatous pyelonephritis infiltrating the liver.

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    Asymptotics of the spectrum of the mixed boundary value problem for the Laplace operator in a thin spindle-shaped domain

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    Free access to full-text articles is allowed 3 years after publication of the corresponding issue. Access to full-text articles of this issue will be allowed starting from April 1, 2024The asymptotics is examined for solutions to the spectral problem for the Laplace operator in a d-dimensional thin, of diameter O(h), spindle-shaped domain Omega(h) with the Dirichlet condition on small, of size h +0, an ordinary differential equation on the axis (-1, 1) (sic) z of the spindle arises with a coefficient degenerating at the points z = +/- 1 and moreover, without any boundary condition because the requirement on the boundedness of eigenfunctions makes the limit spectral problem well-posed. Error estimates are derived for the one-dimensional model but in the case of d = 3 it is necessary to construct boundary layers near the sets Gamma(h)(+/-) and in the case of d = 2 it is necessary to deal with selfadjoint extensions of the differential operator. The extension parameters depend linearly on In h so that its eigenvalues are analytic functions in the variable 1/vertical bar ln h vertical bar As a result, in all dimensions the one-dimensional model gets the power-law accuracy O(h(delta)d ) with an exponent delta(d) > 0. First (the smallest) eigenvalues, positive in Omega(h) and null in (-1, 1), require individual treatment. Also, infinite asymptotic series are discussed, as well as the static problem (without the spectral parameter) and related shapes of thin domains.Peer reviewe

    Voiding school as a treatment of daytime incontinence or enuresis : Children's experiences of the intervention

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    Background Daytime incontinence and enuresis are common problems in otherwise healthy children, and negatively influence their social lives and self-esteem. Motivation for treatment is often a real clinical problem. Children's experiences of their incontinence treatments have not been previously described. Objective The aim of this study was to describe children's experiences of the Voiding School intervention as a treatment for their incontinence. Study design A qualitative, descriptive focus-group study with a purposive sample was conducted at a Finish university hospital in 2014. Children aged 6-12 years participated in the Voiding School at an outpatient clinic. The intervention included two 1-day group visits 2 months apart. The educational content was based on the International Children Continence Society's standards for urotherapy. The education was delivered with child-oriented teaching methods. At the end of the second visit, 19 children were interviewed in five groups. Data were analysed with inductive content analysis. Results The children described incontinence as an embarrassing problem, which they had to hide at any cost. They had experienced bullying and social isolation because of it. Normal outpatient visits emphasized adult-to-adult communication, which made the children feel like outsiders. The children perceived the Voiding School as a nice and child-oriented experience. Making new friends was especially important to younger boys who felt that the Voiding School day was too long and issue-oriented. In the Voiding School, videos and 'learning by doing' helped the children to understand the basis of given advice, and they were able to learn new habits, which gave them control over the incontinence; this helped them to become 'the boss of the bladder'. Sharing experiences and improvements in their incontinence with their peers supported the children's self-esteem and encouraged them to do new things, such as staying overnight with friends. These experiences helped them to acquire control over the problem (Summary Figure). Discussion According to the children's experiences, normal outpatient visits were only appointments for adults, and not very useful for children. In the Voiding School, they were respected as being the main person, and their views were listened to. The results underlined the importance of a child-oriented approach to patient education with regard to children, and provided encouragement to further develop the intervention. Conclusion Child orientation, peer support, learning by doing, and understanding the cause and effect helped children to gain control over their bladders. Based on the children's experiences, this could be achieved by a voiding school.Peer reviewe

    Surgically treated ovarian lesions in preadolescent girls

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    Introduction The purpose of this study was to investigate the epidemiology and characteristics of surgically treated ovarian lesions in preadolescent girls. Material and methods This was a retrospective cohort study including all 0- to 11-year-old girls operated at a single center from 1999 to 2016 for ovarian cysts, neoplasms or torsions. Patient charts were reviewed for symptoms, preoperative radiological imaging, operative details and histopathology. Results We identified 78 girls, resulting in a population-based incidence of 4.2/100 000. Infants (n = 44) presented with benign cysts (42/44, 95%, one bilateral), a benign neoplasm (1/44, 2%) and a torsion without other pathology (1/44, 2%). Torsion was found in 25/29 (86%) ovaries with complex cysts and in 3/15 (21%) ovaries with simple cysts in preoperative imaging (P < 0.001). Most infants were symptomless. Lesions in 1- to 11-year-old girls (n = 34) included benign neoplasms (n = 21/34, 62%), malignant neoplasms (n = 5/34, 15%), a cyst with torsion (n = 1/34, 3%) and torsions without other pathology (n = 7/34, 21%). Torsion was more common in benign (17/21, 81%) than in malignant neoplasms (1/5, 20%) (P < 0.020). Ovarian diameter did not differ between ovaries with or without torsion (P = 0.238) or between benign and malignant neoplasms (P = 0.293). The duration of symptoms in lesions with or without torsion was similar. Conclusions The majority of surgically treated ovarian lesions in preadolescent are benign lesions with torsion. Surgery should be ovary-preserving and performed without delay

    Effects of Rayleigh Waves on the Essential Spectrum in Perturbed Doubly Periodic Elliptic Problems

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    We give an example of a scalar second order differential operator in the plane with double periodic coefficients and describe its modification, which causes an additional spectral band in the essential spectrum. The modified operator is obtained by applying to the coefficients a mirror reflection with respect to a vertical or horizontal line. This change gives rise to Rayleigh type waves localized near the line. The results are proven using asymptotic analysis, and they are based on high contrast of the coefficient functions.Peer reviewe

    Asymptotic analysis of a bit brace shaped junction of thin rods

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    We present a 1-D model of a junction of five thin elastic rods forming the shape of a bit brace (hand drill), or, a crankshaft. The distinguishing feature of this junction is the existence of the so-called movable elements, which are rods and knots requiring modifications of the classical asymptotic ansatze. These consist of constant longitudinal displacements on the edges of the skeleton of the junction and affect the transmission conditions at its nodes. We provide asymptotic formulas for the displacements, stresses and elastic energy, as well as error estimates. An exact solution of the model is given for a particular loading.Peer reviewe
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