Constructional Features of a Multielectrode Electrocardiology Screening System.

The challenges of constructing a noninvasive screening system for electrocardiodiagnostics, focused on visualization of electric potential maps on the surface of the epicardium, is addressed. A functional diagram of a module for recording multiple-lead electrocardiosignals is proposed, the essential component of which is a vest (in several standard sizes) worn by the subject and carrying pre-installed electrodes. Results obtained from experimental verification of the operation of the recording module are presented. The issues of computer processing of electrocardiosignals were addressed and led to the ability to obtain 2D maps of the electric potential on a spherical quasi-epicardium, these 2D maps changing synchronously with changes in the position of the time marker on electrocardiograms familiar to cardiologists.

Conversion from electrocardiosignals to equivalent electrical sources on heart surface.

BACKGROUND: The actual task of electrocardiographic examinations is to increase the reliability of diagnosing the condition of the heart. Within the framework of this task, an important direction is the solution of the inverse problem of electrocardiography, based on the processing of electrocardiographic signals of multichannel cardio leads at known electrode coordinates in these leads (Titomir et al. Noninvasiv electrocardiotopography, 2003), (Macfarlane et al. Comprehensive Electrocardiology, 2nd ed. (Chapter 9), 2011). RESULTS: In order to obtain more detailed information about the electrical activity of the heart, we carry out a reconstruction of the distribution of equivalent electrical sources on the heart surface. In this area, we hold reconstruction of the equivalent sources during the cardiac cycle at relatively low hardware cost. ECG maps of electrical potentials on the surface of the torso (TSPM) and electrical sources on the surface of the heart (HSSM) were studied for different times of the cardiac cycle. We carried out a visual and quantitative comparison of these maps in the presence of pathological regions of different localization. For this purpose we used the model of the heart electrical activity, based on cellular automata. CONCLUSIONS: The model of cellular automata allows us to consider the processes of heart excitation in the presence of pathological regions of various sizes and localization. It is shown, that changes in the distribution of electrical sources on the surface of the epicardium in the presence of pathological areas with disturbances in the conduction of heart excitation are much more noticeable than changes in ECG maps on the torso surface.

Key considerations and challenges in the application of social-network research for environmental decision making.

Attempts to better understand the social context in which conservation and environmental decisions are made has led to increased interest in human social networks. To improve the use of social-network analysis in conservation, we reviewed recent studies in the literature in which such methods were applied. In our review, we looked for problems in research design and analysis that limit the utility of network analysis. Nineteen of 55 articles published from January 2016 to June 2019 exhibited at least 1 of the following problems: application of analytical methods inadequate or sensitive to incomplete network data; application of statistical approaches that ignore dependency in the network; or lack of connection between the theoretical base, research question, and choice of analytical techniques. By drawing attention to these specific areas of concern and highlighting research frontiers and challenges, including causality, network dynamics, and new approaches, we responded to calls for increasing the rigorous application of social science in conservation.

Consideraciones y Retos Importantes en la Aplicación de la Investigación por medio de Redes Sociales para la Toma de Decisiones Ambientales Resumen Los intentos por tener un mejor entendimiento del contexto social en el que se toman las decisiones ambientales y de conservación han derivado en un incremento en el interés por las redes sociales humanas. Para mejorar el uso del análisis de redes sociales en la conservación, buscamos en la literatura los estudios recientes que hayan aplicado dichos métodos y los sometimos a una revisión. En esta revisión, examinamos los problemas en el diseño de la investigación y del análisis que limitan la utilidad del análisis de redes. Diecinueve de los 55 artículos publicados entre enero 2016 y junio 2019 exhibieron al menos uno de los siguientes problemas: aplicación de métodos analíticos inadecuados o sensibles a la información incompleta sobre las redes; aplicación de estrategias estadísticas que ignoran la dependencia en la red; o falta de conexión entre la base teórica, la pregunta de investigación y la selección de técnica analítica. Al llamar la atención hacia estas áreas específicas de interés y resaltar las fronteras y retos de la investigación, incluyendo la causalidad, las dinámicas de redes y las estrategias nuevas, respondimos a la necesidad de incrementar la aplicación rigurosa de las ciencias sociales en la conservación.

Anatomy and resilience of the global production ecosystem.

Much of the Earth's biosphere has been appropriated for the production of harvestable biomass in the form of food, fuel and fibre. Here we show that the simplification and intensification of these systems and their growing connection to international markets has yielded a global production ecosystem that is homogenous, highly connected and characterized by weakened internal feedbacks. We argue that these features converge to yield high and predictable supplies of biomass in the short term, but create conditions for novel and pervasive risks to emerge and interact in the longer term. Steering the global production ecosystem towards a sustainable trajectory will require the redirection of finance, increased transparency and traceability in supply chains, and the participation of a multitude of players, including integrated 'keystone actors' such as multinational corporations.

Improving network approaches to the study of complex social-ecological interdependencies.

Achieving effective, sustainable environmental governance requires a better understanding of the causes and consequences of the complex patterns of interdependencies connecting people and ecosystems within and across scales. Network approaches for conceptualizing and analyzing these interdependencies offer one promising solution. Here, we present two advances we argue are needed to further this area of research: (i) a typology of causal assumptions explicating the causal aims of any given network-centric study of social-ecological interdependencies; (ii) unifying research design considerations that facilitate conceptualizing exactly what is interdependent, through what types of relationships, and in relation to what kinds of environmental problems. The latter builds on the appreciation that many environmental problems draw from a set of core challenges that re-occur across contexts. We demonstrate how these advances combine into a comparative heuristic that facilitates leveraging case-specific findings of social-ecological interdependencies to generalizable, yet context-sensitive, theories based on explicit assumptions of causal relationships.

[Improvement of ECG analysis in monitoring the electrical cardiac activity].

The goal of this work was to suggest a method for improving the efficiency of ECG analysis in measurements of the electrical cardiac activity. The suggested method is based on a solution of the inverse ECG problem. The algorithm for measuring the electrical cardiac activity includes storage of ECG signals from various sources in a database (the body and heart geometry are taken into account), determination of electrically active areas, and determination of the electrical activity at each point of the heart model surface. Test ECG signals available at a free-access web site were used to verify the results of monitoring of the electrical cardiac activity.

[Specific features of electrocardiographic information analysis based on wavelet transform].

Wavelet transform is a new tool for analysis of electrocardiographic information. In this work, we consider the procedure for selection of the mother wavelet on the basis of special criteria and substantiate an improved method for ECG analysis based on wavelet transform. An algorithm for selection of mother wavelet and synthesized wavelet providing optimal wavelet transform of ECG signal is developed. It is shown that 3D wavelet spectrograms should be constructed to increase the efficiency of assessment of the state of cardiovascular system.

[Design principles, structure, and specific features of kardiovid computer diagnostic system].

The design principles and hardware implementation of Kardiovid computer diagnostic system are considered. The system is intended for diagnosis of the state of cardiovascular system on the basis of the results of electrocardiographic and fluorographic examinations. It provides simulation and visualization of the state of cardiovascular system.

[Synthesis of a realistic model of the surface of the heart].

Methods for construction of a model of the surface of the heart and its use for assessing the state of the cardiovascular system are considered. Problems of construction of 3-D models based on Delaney triangulation and Bezier surface are discussed. The necessity for use of computer simulation methods and imaging of the myocardium state at the site of diagnosis is substantiated.