Observational Test of Coronal Magnetic Field Models I. Comparison with Potential Field Model

Recent advances have made it possible to obtain two-dimensional line-of-sight magnetic field maps of the solar corona from spectropolarimetric observations of the Fe XIII 1075 nm forbidden coronal emission line. Together with the linear polarization measurements that map the azimuthal direction of the coronal magnetic field, these coronal vector magnetograms now allow for direct observational testing of theoretical coronal magnetic field models. This paper presents a study testing the validity of potential-field coronal magnetic field models. We constructed a theoretical coronal magnetic field model of active region AR 10582 observed by the SOLARC coronagraph in 2004 by a global potential field extrapolation of the synoptic map of Carrington Rotation 2014. Synthesized linear and circular polarization maps from thin layers of the coronal magnetic field model above the active region along the line of sight are compared with the observed maps. We found that reasonable agreement occurs from layers located just above the sunspot of AR 10582, near the plane of the sky. This result provides the first observational evidence that potential field extrapolation can yield a reasonable approximation of the magnetic field configuration of the solar corona for simple and stable active regions.Comment: 25 pages, 11 figures. ApJ in pres

Urban nighttime leisure space mapping with nighttime light images and POI data

Urban nighttime leisure spaces (UNLSs), important urban sites of nighttime economic activity, have created enormous economic and social benefits. Both the physical features (e.g., location, shape, and area) and the social functions (e.g., commercial streets, office buildings, and entertainment venues) of UNLSs are important in UNLS mapping. However, most studies rely solely on census data or nighttime light (NTL) images to map the physical features of UNLSs, which limits UNLS mapping, and few studies perform UNLS mapping from a social function perspective. Point-of-interest (POI) data, which can reflect social activity functions, are needed. As a result, a novel methodological UNLS mapping framework, that integrates NTL images and POI data is required. Consequently, we first extracted high-NTL intensity and high-POI density areas from composite data as areas with high nightlife activity levels. Then, the POI data were analyzed to identify the social functions of leisure spaces revealing that nighttime leisure activities are not abundant in Beijing overall, the total UNLS area in Beijing is 31.08 km(2), which accounts for only 0.2% of the total area of Beijing. In addition, the nightlife activities in the central urban area are more abundant than those in the suburbs. The main urban area has the largest UNLS area. Compared with the nightlife landmarks in Beijing established by the government, our results provide more details on the spatial pattern of nighttime leisure activities throughout the city. Our study aims to provide new insights into how multisource data can be leveraged for UNLS mapping to enable researchers to broaden their study scope. This investigation can also help government departments better understand the local nightlife situation to rationally formulate planning and adjustment measures

A clinical prediction model based on interpretable machine learning algorithms for prolonged hospital stay in acute ischemic stroke patients: a real-world study

ObjectiveAcute ischemic stroke (AIS) brings an increasingly heavier economic burden nowadays. Prolonged length of stay (LOS) is a vital factor in healthcare expenditures. The aim of this study was to predict prolonged LOS in AIS patients based on an interpretable machine learning algorithm.MethodsWe enrolled AIS patients in our hospital from August 2017 to July 2019, and divided them into the “prolonged LOS” group and the “no prolonged LOS” group. Prolonged LOS was defined as hospitalization for more than 7 days. The least absolute shrinkage and selection operator (LASSO) regression was applied to reduce the dimensionality of the data. We compared the predictive capacity of extended LOS in eight different machine learning algorithms. SHapley Additive exPlanations (SHAP) values were used to interpret the outcome, and the most optimal model was assessed by discrimination, calibration, and clinical utility.ResultsProlonged LOS developed in 149 (22.0%) of the 677 eligible patients. In eight machine learning algorithms, prolonged LOS was best predicted by the Gaussian naive Bayes (GNB) model, which had a striking area under the curve (AUC) of 0.878 ± 0.007 in the training set and 0.857 ± 0.039 in the validation set. The variables sorted by the gap values showed that the strongest predictors were pneumonia, dysphagia, thrombectomy, and stroke severity. High net benefits were observed at 0%–76% threshold probabilities, while good agreement was found between the observed and predicted probabilities.ConclusionsThe model using the GNB algorithm proved excellent for predicting prolonged LOS in AIS patients. This simple model of prolonged hospitalization could help adjust policies and better utilize resources

Application of computer image analysis software for determining incubation period of cavitation erosion – preliminary results

The paper discusses the application of image analysis software ImagePro Plus and MetIlo for assessing cavitation erosion wear. The investigation of cavitation damage is performed on a vibratory test rig in compliance with the ASTM G32 standard using the stationary specimen method. Low-alloy steel grade 34CrNiMo6 is used as the test material. Cavitation wear is evaluated by gravimetric and roughness measurements, microscopic observations and computer image analysis in specified exposure times. The computer image analysis of selected surface areas during a predetermined exposure to cavitation time is performed using images captured with a metallographic microscope. Based on the results of scanning electron and stereoscope microscopic observations, the cavitation worn surfaces are qualitatively described. The relations between surface topography, gravimetric measurements and the microscopic results are discussed. The findings obtained by gravimetric and roughness measurements, image processing and microscopic observations are complementary. The results prove the suitability of image analysis for investigating incubation period of cavitation erosion. The quantification of cavitation erosion damage indicates that the incubation period of cavitation erosion of the tested steel lasts for 20 minutes. The results demonstrate that cavitation-worn surfaces at the initial stage of cavitation erosion can be examined using both ImagePro Plus and MetIlo

A finite volume numerical approach for coastal ocean circulation studies : comparisons with finite difference models

Author Posting. © American Geophysical Union, 2007. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research 112 (2007): C03018, doi:10.1029/2006JC003485.An unstructured grid, finite volume, three-dimensional (3-D) primitive equation coastal ocean model (FVCOM) has been developed for the study of coastal ocean and estuarine circulation by Chen et al. (2003a). The finite volume method used in this model combines the advantage of finite element methods for geometric flexibility and finite difference methods for simple discrete computation. Currents, temperature, and salinity are computed using an integral form of the equations, which provides a better representation of the conservative laws for mass, momentum, and heat. Detailed comparisons are presented here of FVCOM simulations with analytical solutions and numerical simulations made with two popular finite difference models (the Princeton Ocean Model and Estuarine and Coastal Ocean Model (ECOM-si)) for the following idealized cases: wind-induced long-surface gravity waves in a circular lake, tidal resonance in rectangular and sector channels, freshwater discharge onto the continental shelf with curved and straight coastlines, and the thermal bottom boundary layer over the slope with steep bottom topography. With a better fit to the curvature of the coastline using unstructured nonoverlapping triangle grid cells, FVCOM provides improved numerical accuracy and correctly captures the physics of tide-, wind-, and buoyancy-induced waves and flows in the coastal ocean. This model is suitable for applications to estuaries, continental shelves, and regional basins that feature complex coastlines and bathymetry.This research was supported by the U.S. GLOBEC Northwest Atlantic/Georges Bank program through NSF grants OCE-0234545, OCE-0227679, NOAA grant NA 160P2323, and NSF CoOP grant OCE-0196543 to C. Chen and NSF OCE-0227679 and the WHOI Smith Chair to R. C. Beardsley. H. Huang and Q. Xu were supported by Chen’s Georgia and South Carolina Sea Grant awards NA06RG0029 and NA960P0113. G. Cowles was supported by the SMAST fishery program through NOAA grants DOC/NOAA/NA04NMF4720332 and DOC/NOAA/NA05NMF4721131

Penyelesaian Tindak Pidana Perjudian yang Dilakukan oleh Anak Menurut UU No.11 Tahun 2012

The title of this legal writing is "The Completion of the Crime of Gambling Carried Out by minors based on the law Number 11 of 2012 on the Juvenile Justice system". This type of research is normative legal research. Normative legal research is a research conducted or focusing on norm of positive law in the form of legislation. Legal issues raised is whether the completion of the crime of gambling by children is in conformity with the law Number 11 of 2012 about the juvenile justice system. The purpose of this research is to determine and analyze the completion of the crime of gambling by children under the law of the juvenile justice system. The result showed that the efforts made to prevent criminal acts of a child is an attempt preventive and repressive efforts. Juvenile justice system is closely related to restorative justice. Regarding the obligation to make a diversion conducted by law enforcement officials, in particular under Article 7 and 96 of the law number 11 of 2012 on the Juvenile Justice System

Determination of Frequency-Dependent Shear Modulus of Viscoelastic Layer via a Constrained Sandwich Beam

Viscoelastic material can significantly reduce the vibration energy and radiated noise of a structure, so it is widely used in lightweight sandwich structures. The accurate and efficient determination of the frequency-dependent complex modulus of viscoelastic material is the basis for the correct analysis of the vibro-acoustic behavior of sandwich structures. Based on the behavior of a sandwich beam whose core is a viscoelastic layer, a combined theoretical and experimental study is proposed to characterize the properties of the viscoelastic layer constituting the core. In this method, the viscoelastic layer is bonded between two constraining layers. Then, a genetic algorithm is used to fit the analytical solution of the frequency¬ response function of the free–free constrained beam to the measured result, and then the frequency-dependent complex modulus is estimated for the viscoelastic layer. Moreover, by varying the length of the beams, it is possible to characterize the frequency-dependent complex modulus of the viscoelastic material over a wide frequency range. Finally, the characterized frequency-dependent complex modulus is imported into a finite element model to compute the complex natural frequencies of a sandwich beam, and a comparison of the simulated and measured results displays that the errors in the real parts are within 2.33% and the errors in the imaginary parts are within 3.31%. It is confirmed that the proposed method is feasible, accurate, and reliable. This provides essential technical support for improving the acoustic vibration characteristics of sandwich panels by introducing viscoelastic materials