561 research outputs found

    Accelerating the Lawson-Hanson NNLS solver for large-scale Tchakaloff regression designs

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    We deal with the problem of computing near G-optimal compressed designs for high-degree polynomial regression on fine discretizations of 2d and 3d regions of arbitrary shape. The key tool is Tchakaloff-like compression of discrete probability measures, via an improved version of the Lawson-Hanson NNLS solver for the corresponding full and large-scale underdetermined moment system, that can have for example a size order of 10\u2c63 (basis polynomials) x 10\u2c64 (nodes)

    dCATCH—A Numerical Package for d-Variate near G-Optimal Tchakaloff Regression via Fast NNLS

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    We provide a numerical package for the computation of a d-variate near G-optimal polynomial regression design of degree m on a finite design space X ⊂ R d , by few iterations of a basic multiplicative algorithm followed by Tchakaloff-like compression of the discrete measure keeping the reached G-efficiency, via an accelerated version of the Lawson-Hanson algorithm for Non-Negative Least Squares (NNLS) problems. This package can solve on a personal computer large-scale problems where c a r d ( X ) × dim ( P 2 m d ) is up to 10 8 – 10 9 , being dim ( P 2 m d ) = 2 m + d d = 2 m + d 2 m . Several numerical tests are presented on complex shapes in d = 3 and on hypercubes in d > 3

    Postnatal growth in a cohort of Sardinian intrauterine growth-restricted infants

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    Recent studies have shown that infants with intrauterine growth restriction (IUGR) undergo catch-up growth during infancy. The aim of our study was to evaluate the postnatal growth in a cohort of IUGR infants born in a tertiary-level Obstetric University Hospital of Northern Sardinia. An observational retrospective study was conducted on 12 IUGR (group A) and 12 control infants (group B) by measuring the anthropometric parameters of weight (W), length (L) and head circumference (HC) from birth to the 3rd postnatal year. At birth, significant differences were found between group A and group B with regard to all the auxological parameters (W, mean 1846.6 versus 3170.8 g, p < 0.0001; HC, 30.1 versus 34.4 cm, p < 0.0001; L, mean 43.4 versus 49.4 cm, p < 0.0001). During the 1st year, 8 of 12 (70%) IUGR infants exhibited a significant catch-up growth in the 3 anthropometric parameters and a regular growth until the 3rd year of follow-up. The majority but not all infants born with IUGR in our series showed significant postnatal catch-up growth essentially during the first 12 months of life. An improved knowledge of the causes of IUGR will help to develop measures for its prevention and individualized treatment

    Expression analysis of HLA-E and NKG2A and NKG2C receptors points at a role for natural killer function in ankylosing spondylitis

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    Background. Ankylosing Spondylitis (AS) is a complex chronic inflammatory disease strongly associated with the majority of HLA-B27 alleles. HLA-E are non-classical MHC class I molecules that specifically interact with the natural killer receptors NKG2A (inhibitory) and NKG2C (activating), and have been recently proposed to be involved in AS pathogenesis. Objectives: To analyze the expression of HLA-E and the CD94/NKG2 pair of receptors in HLA-B27 positive AS patients and healthy controls (HC) bearing the AS-associated, B*2705 and the non-AS-associated, B*2709 allele. Methods: The level of surface expression of HLA-E molecules on CD14 positive peripheral blood mononuclear cell was evaluated in 21 HLA-B*2705 patients with AS, 12 HLA-B*2705 HC, 12 HLA-B*2709 HC and 6 HLA-B27 negative HC, using the monoclonal antibody MEM-E/08 by quantitative cytofluorimetric analysis. The percentage and density of expression of HLA-E ligands NKG2A and NKG2C were also measured on CD3-CD56+ NK cells. Results. HLA-E expression in CD14 positive cells was significantly higher in AS patients (587.0 IQR 424-830) compared to B*2705 HC (389 IQR 251.3-440.5, p=0.0007), B*2709 HC (294.5 IQR 209.5-422, p=0.0004) and HLA-B27 negative HC (380 IQR 197.3-515.0, p=0.01). A higher number of NK cells expressing NKG2A compared to NKG2C was found in all cohort analysed as well as a higher cell surface density. Conclusion: The higher surface level of HLA-E molecules in AS patients compared to HC, concurrently with a prevalent expression of NKG2A, suggests that the crosstalk between these two molecules might play a role in AS pathogenesis accounting for the previously reported association between HLA-E and AS

    The Autonomic and sensitive innervation of the ostrich copulatory organ

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    The autonomic and sensitive innervation of the ostrich copulatory organ was studied. The former consisted by isolated and grouped ganglion cells, located along the course of nerve bundles or in the convegence point of two or more of these fascicles. The latter is represented by free and encapsulated nerve terminations. These last one, morphologically classified as Pacini, Pacini-like and genital corpuscles,showed the typical structure and could be found isolated or assembled to organize flower-sprays, opposite-polar corpuscles or poikilomorphous nerve fibres. The Pacini corpuscles were numerically prevalent, while the Pacini-like terminations represented the less numerous receptorial type
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