Search results for "Transform"
showing 10 items of 3975 documents
Modified Operators Interpolating at Endpoints
2021
Some classical operators (e.g., Bernstein) preserve the affine functions and consequently interpolate at the endpoints. Other classical operators (e.g., Bernstein–Durrmeyer) have been modified in order to preserve the affine functions. We propose a simpler modification with the effect that the new operators interpolate at endpoints although they do not preserve the affine functions. We investigate the properties of these modified operators and obtain results concerning iterates and their limits, Voronovskaja-type results and estimates of several differences.
Some Improvements on Relativistic Positioning Systems
2018
[EN] We make some considerations about Relativistic Positioning Systems (RPS). Four satellites are needed to position a user. First of all we define the main concepts. Errors should be taken into account. Errors depend on the Jacobian transformation matrix. Its Jacobian is proportional to the tetrahedron volume whose vertexes are the four tips of the receiver-satellite unit vectors. If the four satellites are seen by the user on a circumference in the sky, then, the Jacobian and the tetrahedron volume vanish. The users we consider are spacecraft. Spacecraft to be positioned cannot be close to a null Jacobian satellites-user configuration. These regions have to be avoided choosing an appropr…
Irregular motion recovery in fluorescein angiograms
1997
Abstract Fluorescein angiography is a common procedure in ophthalmic practice, mainly to evaluate vascular retinopathies and choroidopathies from sequences of ocular fundus images. In order to compare the images, a reliable overlying is essential. This paper proposes some methods for the recovery of irregular motion in fluorescein angiograms (FA). The overlying is done by a three step procedure: detection of relevant points, matching points from different images and estimation of the assumed linear geometric transformation. A stochastic model (closely related to the general linear model) allows to fuse the second and third steps. Two different estimators of the geometric transformation are …
The Study of Dynamic Objects Identification Algorithms Based on Anisotropic Properties of Generalized Amplitude-Phase Images
2018
The article presents some results of dynamical objects identification technology based on coincidence matrixes of templates and tested objects’ amplitude-phase images (APIm) calculated with discrete Hilbert transforms (DHT). DHT algorithms are modeled on basis of isotropic (HTI), anisotropic (HTA), generalized transforms – AP-analysis (APA) and the difference (residual) relative shifted phase (DRSP-) images to calculate the APIm. The identified objects are recognized as members of classes modeled with 3D templates – images of different types airplanes rotated in space. The dynamic anisotropic properties of APIm causes the increasing of sensitivity to circular angle rotation and make possibl…
Eight Simple Guidelines for Improved Understanding of Transformations and Nonlinear Effects
2021
Jyväskylästä kirjoitettiin: Käyn läpi Extra-Vipusessa ristiriitaisiksi luokitettuja yhteisjulkaisuja. Julkaisu " Eight Simple Guidelines for Improved Understanding of Transformations and Nonlinear Effects" on meillä laitettu A2 ja teillä A1. Meillä varmaan päädytty tuohon A2:een kun tiivistelmässä sanotaan "Building on a systematic review of six leading management journals..". Mutta mitä mieltä olette, kumpi olisi parempi? Transforming variables before analysis or applying a transformation as a part of a generalized linear model are common practices in organizational research. Several methodological articles addressing the topic, either directly or indirectly, have been published in the rec…
Role of Gadd45a in Wip1-dependent regulation of intestinal tumorigenesis.
2012
Conversion of intestinal stem cells into tumor-initiating cells is an early step in Apc(Min)-induced polyposis. Wild-type p53-induced phosphatase 1 (Wip1)-dependent activation of a DNA damage response and p53 has a permanent role in suppression of stem cell conversion, and deletion of Wip1 lowers the tumor burden in Apc(Min) mice. Here we show that cyclin-dependent kinase inhibitor 2a, checkpoint kinase 2, and growth arrest and DNA damage gene 45a (Gadd45a) exert critical functions in the tumor-resistant phenotype of Wip1-deficient mice. We further identified Gadd45a as a haploinsufficient gene in the regulation of Wip1-dependent tumor resistance in mice. Gadd45a appears to function through…
An Innovative Structural Dynamic Identification Procedure Combining Time Domain OMA Technique and GA
2022
In this paper an innovative and simple Operational Modal Analysis (OMA) method for structural dynamic identification is proposed. It combines the recently introduced Time Domain–Analytical Signal Method (TD–ASM) with the Genetic Algorithm (GA). Specifically, TD–ASM is firstly employed to estimate a subspace of candidate modal parameters, and then the GA is used to identify the structural parameters minimizing the fitness value returned by an appropriately introduced objective function. Notably, this method can be used to estimate structural parameters even for high damping ratios, and it also allows one to identify the Power Spectral Density (PSD) of the structural excitat…
Cutting Edge: TGF-β Signaling Is Required for the In Vivo Expansion and Immunosuppressive Capacity of Regulatory CD4+CD25+ T Cells
2004
Abstract Data regarding the role of TGF-β for the in vivo function of regulatory CD4+CD25+ T cells (Treg) are controversial. A transgenic mouse model with impaired TGF-β signaling specifically in T cells was used to assess the role of endogenous TGF-β for the in vivo function of CD4+CD25+ Treg in a murine model of colitis induced by dextran sulfate. Transfer of wild-type, but not transgenic CD4+CD25+ Treg was found to suppress colitis in wild-type mice. In addition, by transferring CFSE-labeled CD4+CD25+ Treg we could demonstrate that endogenous TGF-β promotes the expansion of CD4+CD25+ Treg in vivo. Transgenic mice themselves developed reduced numbers of peripheral CD4+CD25+ Treg and were …
T Cell-Specific Overexpression of TGFß1 Fails to Influence Atherosclerosis in ApoE-Deficient Mice
2013
Clinical data have indicated a negative correlation between plasma TGFß1 concentrations and the extent of atherosclerosis and have thus led to the hypothesis that the pleiotropic cytokine may have anti-atherogenic properties. T-cells are currently discussed to significantly participate in atherogenesis, but the precise role of adaptive immunity in atherogenesis remains to be elucidated. TGFß1 is known to strongly modulate the function of T-cells, however, inhibition of TGFß1 signalling in T-cells of atherosclerosis-prone knock-out mice failed to unequivocally clarify the role of the cytokine for the development of atherosclerosis. In the present study, we thus tried to specify the role of T…
Overexpression of TGF-ß1 in macrophages reduces and stabilizes atherosclerotic plaques in ApoE-deficient mice.
2011
Although macrophages represent the hallmark of both human and murine atherosclerotic lesions and have been shown to express TGF-ß1 (transforming growth factor β1) and its receptors, it has so far not been experimentally addressed whether the pleiotropic cytokine TGF-ß1 may influence atherogenesis by a macrophage specific mechanism. We developed transgenic mice with macrophage specific TGF-ß1 overexpression, crossed the transgenics to the atherosclerotic ApoE (apolipoprotein E) knock-out strain and quantitatively analyzed both atherosclerotic lesion development and composition of the resulting double mutants. Compared with control ApoE(-/-) mice, animals with macrophage specific TGF-ß1 overe…