The phenomenon of probability backflow, previously quantified for a free nonrelativistic particle, is considered for a free particle obeying Dirac's equation. It is shown that probability backflow can occur in the opposite direction to the momentum; that is to say, there exist positive-energy states in which the particle certainly has a positive momentum in a given direction, but for which the component of the probability flux vector in that direction is negative. It is shown that the maximum possible amount of (...) probability that can flow “backwards,” over a given time interval of duration T, depends on the dimensionless parameter ε = (4ℏ/mc2T)1/2, where m is the mass of the particle and c is the speed of light. At ε = 0, the nonrelativistic value of approximately 0.039 for this maximum is recovered. Numerical studies suggest that the maximum decreases monotonically as ε increases from 0, and show that it depends on the size of m, ℏ, and T, unlike the nonrelativistic case. (shrink)

gl. 1. Geopoliticheskai︠a︡ determinat︠s︡ii︠a︡ kulʹtury i ėkonomiki. Rolʹ geograficheskikh faktorov v razvitii obshchestva ; Geopoliticheskie osobennosti sot︠s︡iokulʹturnoĭ istorii Rossii -- gl. 2. Kulʹturnai︠a︡ sostavli︠a︡i︠u︡shchai︠a︡ geopolitiki. Kulʹtura kak instrument geopolitiki ; Dialog kulʹtur v sovremennom mire: opasnai︠a︡ illi︠u︡zii︠a︡, otchai︠a︡nnai︠a︡ vera ili velenie vremeni?

Different approaches have been proposed in order to achieve knowledge integration for coronary care monitoring applications, usually in the form of expert systems. The clinical impact of these expert systems, which are based only on "shallow" knowledge, has not been remarkable due to the difficulties associated with the construction and maintenance of a complete knowledge base. Model-based systems represent an alternative to these problems because they allow efficient integration of the "deep" knowledge on the underlying physiological phenomena being monitored. In (...) this work, a brief review of existing model-based systems for cardiac rhythm interpretation is presented, followed by the description of a new system forCardiac Arrhythmia Recognition by Model-Based ECG Matching (CARMEM). Fundamental characteristics of CARMEM are presented; in particular, its ability to provide on-line parameter adaptation to simulate complex rhythms and to match observed ECG signals. The proposed model can be useful for the explanation of the origin of cardiac arrhythmias and contribute towards their robust characterization in the context of coronary care units. (shrink)

Brain tumor classification plays a niche role in medical prognosis and effective treatment process. We have proposed a combined feature and image-based classifier for brain tumor image classification in this study. Carious deep neural network and deep convolutional neural networks -based architectures are proposed for image classification, namely, actual image feature-based classifier, segmented image feature-based classifier, actual and segmented image feature-based classifier, actual image-based classifier, segmented image-based classifier, actual and segmented image-based classifier, and finally, CFIC. The Kaggle Brain Tumor Detection (...) 2020 dataset has been used to train and test the proposed classifiers. Among the various classifiers proposed, the CFIC performs better than all other proposed methods. The proposed CFIC method gives significantly better results in terms of sensitivity, specificity, and accuracy with 98.86, 97.14, and 98.97%, respectively, compared with the existing classification methods. (shrink)

This paper examines the arguments presented by the Roman Catholic Bishops in their 1993 Pastoral Resolution, Comprehensive Health Care Reform: Protecting Human Life, Promoting Human Dignity, Pursuing the Common Good, concerning health care reform. Focusing on the meaning of equality in health care and traditional Roman Catholic doctrine, it is argued that the Bishops fail to grasp the force of the differences among persons, the value of the market, and traditional scholastic arguments concerning obligatory and extraordinary health care. To attempt (...) to equalize the distribution of health care would be ruinous. A more traditional understanding of Christian thought reveals an acceptance of inequality in health care distribution and a bias against using the secular state to coerce a solution to such concerns for social justice. (shrink)

This paper describes the topological aspect of a logic-based, artificial intelligence approach to formalising the qualitative description of spatial properties and relations, and reasoning about those properties and relations. This approach, known as RCC theory, has been under development for several years at the University of Leeds. The main rationale for this project is that qualitative descriptions of spatial properties and relationships, and qualitative spatial reasoning, are of fundamental importance in human thinking about the world: even where quantitative spatial data (...) are most important, they must be attached to the components of a perceived spatial structure if we are to make use of them. RCC theory covers other qualitative aspects of spatial description and reasoning, but the topological properties and relations of spatially extended entities are fundamental to our work. The topological formalisms used by mathematicians are, in general, not well suited to the task of formalising the kinds of ‘common-sense’ or ‘everyday’ qualitative spatial description and reasoning which are our primary interest. Nevertheless, we must come to grips with the concepts of topology as practised by mathematicians if we are not to risk constantly ‘reinventing wheels’. (shrink)

Bateson's belated acceptance of the chromosome theory came in two main stages, and was permanent, although he retained to the end reservations about some implications and extensions of the theory. Coleman's attempt to explain Bateson's resistance in terms of his conservative mode of thought is critically examined, and rejected: the attributes Coleman assigns to Bateson are all either inappropriate, or irrelevant to chromosome theory, or both. Instead, the diverse factors which contributed to Bateson's resistance are enumerated and discussed. These include (...) deficiencies in the evidence then available to support the theory; embryological difficulties; Bateson's aversion to microscopy combined with the lack of a close colleague skilled in cytology; his iconoclastic temperament, and the fact that he found T. H. Morgan, the leader of the Drosophila school, an uncongenial personality. Taken together, these factors suffice to account for his resistance. Bateson's position is contrasted with that of the other most eminent opponent, W. Johannsen, whose organismic outlook was the main obstacle to acceptance. (shrink)

At the present stage, the problem of human ecology is determined, for all practical purposes, by the response of man to the conditions of the environment he has himself modified and created.

The author, head of a teaching hospital surgical unit, argues that the medical curriculum must ensure that all students are exposed to a minimum of ethical discussion and decision-making. In describing his own approach he emphasises the need to show students that it is 'an intensely practical subject'. Moreover, he reminds them that moral dilemmas in medicine--perhaps a better term than medical ethics--are unavoidable in clinical practice. Professor Johnson emphasises the need for small group teaching and discussion of real cases, (...) preferably chosen and 'worked up' by individual students. He suggests that ethical issues could profitably be introduced into written, oral and clinical examinations. (shrink)

Dilemmas about resuscitation and life-prolonging treatment for severely compromised infants have become increasingly complex as skills in neonatal care have developed. Quality of life and resource issues necessarily influence management. Our Institute of Medical Ethics working party, on whose behalf this paper is written, recognises that the ultimate responsibility for the final decision rests with the doctor in clinical charge of the infant. However, we advocate a team approach to decision-making, emphasising the important role of parents and nurses in the (...) process. Assessing the relative burdens and benefits can be troubling, but doctors and parents need to retain a measure of discretion; legislation which would determine action in all cases is inappropriate. Caution should be exercised in involving committees in decision-making and, where they exist, their remit should remain to advise rather than to decide. Support for families who bear the consequences of their decisions is often inadequate, and facilitating access to such services is part of the wider responsibilities of the intensive care team. The authors believe that allowing death by withholding or withdrawing treatment is legitimate, where those closely involved in the care of the infant together deem the burdens to be unacceptable without compensating benefits for the infant. As part of the process accurate and careful recording is essential. (shrink)