reflection model
Recently Published Documents


TOTAL DOCUMENTS

271
(FIVE YEARS 77)

H-INDEX

19
(FIVE YEARS 3)

2021 ◽  
pp. 152715442110677
Author(s):  
Norlissa M. Cooper ◽  
Audrey Lyndon ◽  
Monica R. McLemore ◽  
Ifeyinwa V. Asiodu

Perinatal illicit substance use is a nursing and public health issue. Current screening policies have significant consequences for birthing individuals and their families. Racial disparities exist in spite of targeted and universal screening policies and practices. Thus, new theoretical approaches are needed to investigate perinatal illicit substance use screening in hospital settings. The purpose of this analysis is to evaluate the social construction of target populations theory in the context of perinatal illicit substance use screening. Using the theoretical insights of this theory to interrogate the approaches taken by policy makers to address perinatal illicit substance use and screening provides the contextual framework needed to understand why specific policy tools were selected when designing public policy to address these issues. The analysis and evaluation of this theory was conducted using the theory description and critical reflection model.


Author(s):  
xiaogu zhong ◽  
Jiancheng Wang

Abstract We review the Seyfert 1.5 Galaxy ESO 362-G18 for exploring the origin of the soft X-ray excess. The Warm Corona and Relativistic Reflection models are two main scenarios to interpret the soft X-ray excess in AGNs at present. We use the simultaneous X-ray observation data of XMM-Newton and NuSTAR on Sep. 24th, 2016 to perform spectral analysis in two steps. First, we analyze the time-average spectra by using Warm Corona and Relativistic Reflection models. Moreover, we also explore the Hybrid model, Double Reflection model and Double Warm Corona model. We find that both of Warm Corona and Relativistic Reflection models can interpret the time-average spectra well but cannot be distinguished easily based on the time-averaged spectra fit statistics. Second, we add the RMS and covariance spectra to perform the spectral analysis with time-average spectra. The result shows that the warm corona could reproduce all of these spectra well. The the hot, optical thin corona and neutral distant reflection will increase their contribution with the temporal frequency, meaning that the corona responsible for X-ray continuum comes from the inner compact X-ray region and the neutral distant reflection is made of some moderate scale neutral clumps.


2021 ◽  
Vol 923 (2) ◽  
pp. 175
Author(s):  
Askar B. Abdikamalov ◽  
Dimitry Ayzenberg ◽  
Cosimo Bambi ◽  
Honghui Liu ◽  
Ashutosh Tripathi

Abstract In this paper we present relxilldgrad_nk, a relativistic reflection model in which the electron density of the accretion disk is allowed to have a radial power-law profile. The ionization parameter also has a nonconstant radial profile and is calculated self-consistently from the electron density and the emissivity. We show the impact of the implementation of the electron density gradient in our model by analyzing a NuSTAR spectrum of the Galactic black hole in EXO 1846–031 during its last outburst in 2019 and a putative future observation of the same source with Athena and eXTP. For the NuSTAR spectrum, we find that the new model provides a better fit, but there is no significant difference in the estimation of the model parameters. For the Athena+eXTP simulation, we find that a model without a disk density profile is unsuitable to test the spacetime metric around the compact object in the sense that modeling uncertainties can incorrectly lead to finding a nonvanishing deformation from the Kerr solution.


2021 ◽  
Vol 13 (22) ◽  
pp. 4701
Author(s):  
Guan Yang ◽  
Chao Li ◽  
Shiyou Wu ◽  
Shen Zheng ◽  
Xiaojun Liu ◽  
...  

In multiple-input-multiple-output synthetic aperture radar (MIMO-SAR) systems, sparse arrays are usually applied, resulting in increased sidelobes of the point spread function. In this paper, a phase shift migration (PSM) imaging algorithm based on the explosion reflection model with modified coherent factor was proposed for sidelobe suppression in MIMO-SAR three-dimensional (3D) imaging application. By defining the virtual difference wavenumber, reconstructing the raw echo by data rearrangement in wavenumber domain, the original coherent factor algorithm operating in spatial domain can be achieved by the PSM algorithm frame in the wavenumber domain, which means two orders of magnitude increase in computational efficiency. The correctness of the theory is verified by simulation. Finally, a bistatic prototype imaging system in the 0.3 THz band was designed for the proof-of-principle experiments. The experimental results show that the proposed algorithm has a 0.948 structural similarity value to the original coherent factor back-projection algorithm (CF-BPA) which means comparable image quality with much superior efficiency.


2021 ◽  
pp. 108400
Author(s):  
Shuhe Zhang ◽  
Carroll A.B. Webers ◽  
Tos T.J.M. Berendschot

2021 ◽  
Author(s):  
Satoshi Wakebe ◽  
Kotaro Yamasue ◽  
Hidetoshi Itoh

<p>We propose a new method and software for measuring blood vessel diameters from fundus photographs. In this method the edge of the blood vessel is the two minimum points in the luminance profile and diameter is distance between minimum points. We noticed the relation between W-shape of luminance profile at blood vessel transversal line and cylindrical shape, and analyzed the validity of this method using the diffuse reflection model of a cylinder shape based on the optics. The simulation image by the diffuse reflection model of the cylinder was similar to that of the blood vessel images. A newly developed software using the minimum points can measure repeated measurement in a series of photographs at the same point of the same person. The data of the repeated measurement of each person showed stability, and the coefficient of variation showed no affection of different diameter and arteriovenous distinction. Hence, we believe that the minimum points are valid as blood vessel edges. The software that measures these blood vessel edges has an extremely simple measurement procedure, possesses few errors, and is easy to automate. This method is relevant because the central reflex, which has not been utilized previously, optically represents the cylindrical three-dimensional structure of blood vessels.</p><div><div> </div> </div>


2021 ◽  
Author(s):  
Satoshi Wakebe ◽  
Kotaro Yamasue ◽  
Hidetoshi Itoh

<p>We propose a new method and software for measuring blood vessel diameters from fundus photographs. In this method the edge of the blood vessel is the two minimum points in the luminance profile and diameter is distance between minimum points. We noticed the relation between W-shape of luminance profile at blood vessel transversal line and cylindrical shape, and analyzed the validity of this method using the diffuse reflection model of a cylinder shape based on the optics. The simulation image by the diffuse reflection model of the cylinder was similar to that of the blood vessel images. A newly developed software using the minimum points can measure repeated measurement in a series of photographs at the same point of the same person. The data of the repeated measurement of each person showed stability, and the coefficient of variation showed no affection of different diameter and arteriovenous distinction. Hence, we believe that the minimum points are valid as blood vessel edges. The software that measures these blood vessel edges has an extremely simple measurement procedure, possesses few errors, and is easy to automate. This method is relevant because the central reflex, which has not been utilized previously, optically represents the cylindrical three-dimensional structure of blood vessels.</p><div><div> </div> </div>


Sign in / Sign up

Export Citation Format

Share Document