Determination of adjusted range corrections measured by electro-optical systems

Electromagnetic radiation used to determine ranges passes through media with different characteristics that affect the electromagnetic waves propagation speed and, accordingly, the accuracy of distance determination. The problem of the radio signal delay due to the influence of the atmosphere is an urgent problem, the solution of which is currently limited mainly to the calculation of range corrections using various atmospheric models. Depending on the required accuracy, the length of the measured line, the range of zenith distances, the availability of information about the state of the atmosphere, a flat, spherical, ellipsoidal model of atmospheres is used to determine the range corrections. In view of the fact that the parameters of the atmosphere characterizing its state along the electromagnetic wave path at the time of measurement, as a rule, are unknown, it becomes necessary to apply one or another hypothesis about the distribution of atmospheric parameters with height. In this paper, we propose a solution to the problem of determining corrections to the measured ranges from the known parameters of the atmosphere only at the initial and final points of the electromagnetic waves’ trajectory.

Tertiary lymphoid structures (TLS) identification and density assessment on H&E-stained digital slides of lung cancer

Tertiary lymphoid structures (TLS) are ectopic aggregates of lymphoid cells in inflamed, infected, or tumoral tissues that are easily recognized on an H&E histology slide as discrete entities, distinct from lymphocytes. TLS are associated with improved cancer prognosis but there is no standardised method available to quantify their presence. Previous studies have used immunohistochemistry to determine the presence of specific cells as a marker of the TLS. This has now been proven to be an underestimate of the true number of TLS. Thus, we propose a methodology for the automated identification and quantification of TLS, based on H&E slides. We subsequently determined the mathematical criteria defining a TLS. TLS regions were identified through a deep convolutional neural network and segmentation of lymphocytes was performed through an ellipsoidal model. This methodology had a 92.87% specificity at 95% sensitivity, 88.79% specificity at 98% sensitivity and 84.32% specificity at 99% sensitivity level based on 144 TLS annotated H&E slides implying that the automated approach was able to reproduce the histopathologists’ assessment with great accuracy. We showed that the minimum number of lymphocytes within TLS is 45 and the minimum TLS area is 6,245μm2. Furthermore, we have shown that the density of the lymphocytes is more than 3 times those outside of the TLS. The mean density and standard deviation of lymphocytes within a TLS area are 0.0128/μm2 and 0.0026/μm2 respectively compared to 0.004/μm2 and 0.001/μm2 in non-TLS regions. The proposed methodology shows great potential for automated identification and quantification of the TLS density on digital H&E slides.

On the propagation of waves in the atmosphere

The leading-order equations governing the unsteady dynamics of large-scale atmospheric motions are derived, via a systematic asymptotic approach based on the thin-shell approximation applied to the ellipsoidal model of the Earth’s geoid. We present some solutions of this single set of equations that capture properties of specific atmospheric flows, using field data to choose models for the heat sources that drive the motion. In particular, we describe standing-waves solutions, waves propagating towards the Equator, equatorially trapped waves and we discuss the African Easterly Jet/Waves. This work aims to show the benefits of a systematic analysis based on the governing equations of fluid dynamics.

Modelling the Influence of Electromagnetic Field on the User of a Wearable IoT Device Used in a WSN for Monitoring and Reducing Hazards in the Work Environment

The aim of this study was to evaluate the absorption in a user’s head of an electromagnetic field (EMF) emitted by the Wi-Fi and/or Bluetooth module of a wearable small Internet of Things (IoT) electronic device (emitting EMF of up to 100 mW), in order to test the hypothesis that EMF has an insignificant influence on humans, and to compare the levels of such EMF absorption in various scenarios when using this device. The modelled EMF source was a meandered inverted-F antenna (MIFA)-type antenna of the ESP32-WROOM-32 radio module used in wearable devices developed within the reported study. To quantify the EMF absorption, the specific energy absorption rate (SAR) values were calculated in a multi-layer ellipsoidal model of the human head (involving skin, fat, skull bones and brain layers). The obtained results show up to 10 times higher values of SAR from the MIFA located in the headband, in comparison to its location on the helmet. Only wearable IoT devices (similar in construction and way of use to the investigated device) emitting at below 3 mW equivalent isotropically radiated power (EIRP) from Wi-Fi/Bluetooth communications modules may be considered environmentally insignificant EMF sources.

Modelling the Influence of the 2.4 GHz Electromagnetic Field on the User of a Wearable Internet of Things (IoT) Device for Monitoring Hazards in the Work Environment

The aim was to test the hypothesis that there is an insignificant influence on humans from the absorption of an 2.4 GHz electromagnetic field (EMF) emitted by wearable Internet of Things (IoT) devices (using Meandered Inverted-F Antenna (MIFA) for Wi-Fi and Bluetooth technologies) for monitoring hazards in the work environment. To quantify problem, the specific energy absorption rate (SAR) was calculated in a multi-layer ellipsoidal model of the IoT device user’s head exposed to EMF from MIFA attached to a headband or to a helmet. SAR values may be significant when a modelled IoT wearable device is attached to a headband, but not to a helmet.

Echocardiographic Assessment of the Left Ventricular Physical Parameters: A Comparison Study in Patients With Significant and Non-Significant Coronary Artery Disease

BackgroundIn this study, physical parameters of the strain of left ventricle (LV), wall stress with a thick-walled ellipsoidal model, and elastic modulus of LV were extracted for distinguishing patients who were stent candidates.Materials and MethodsEighty-eight patients with suspected coronary artery disease (CAD) underwent echocardiography and angiography. Based on angiography results, the patients were divided into two groups (64 patients candidate for PCI (percutaneous coronary intervention) and 24 cases in the control group). Long-axis and short-axis echocardiographic views were acquired. Radial, longitudinal, and circumferential stress were estimated by the thick-walled ellipsoidal model. Circumferential strain (CS) and longitudinal strain (Ls) were obtained for 18 segments in the endocardium layer of LV, and then GLS (global longitudinal strain) and GCS (global circumferential strain) were calculated.ResultAnterior and inferoseptal circumferential wall stresses in end-systole (ES) were statistically significant (P<0.05), but radial and longitudinal stress were not significant (P>0.05). Peak systolic GCS and GLS were lower in the PCI group (-18.13±3.03 and -16.57±2.88%) compared to the control group (-21.97±3.97 and 19.14±2.17%), respectively (p<0.05). The receiver operator characteristic curve (ROC) analysis revealed that GLS and GCS had the highest area under the ROC curve with a sensitivity of 83% and specificity of 63% for GLS and sensitivity of 71% and specificity of 59% for GCS.ConclusionStress and strain parameters are suggested as non-invasive and quantitative tools for measuring left ventricular function before angiography. Regional elastic modulus was a powerful predictor that can be distinguishing significant CAD patients.

Which Part of the Neuronal Current can be Determined by Electroencephalography?

This chapter considers the so-called four-shell model of the brain and assumes that a continuously distributed primary neuronal current is supported either within the cerebral cortex or only on the surface of the cortex, S c, and is normal to this surface. The authors show that in the former case, electroencephalogram recordings are affected only by the value of the irrotational part of the current denoted by the scalar function Ψ‎(τ‎) and by the gradient of Ψ‎(τ‎) on S c. An effective numerical procedure for reconstructing Ψ‎(τ‎) in the particular case of an ellipsoidal model is discussed. If the primary current is supported on S c, and it is normal to it, then it can be reconstructed uniquely.