The study of the autonomic nervous system (ANS) function has shown to provide useful indicators for risk stratification and early detection on a variety of cardiovascular pathologies. However, data gathered during different tests of the ANS are difficult to analyse, mainly due to the complex mechanisms involved in the autonomic regulation of the cardiovascular system (CVS). Although model-based analysis of ANS data has been already proposed as a way to cope with this complexity, only a few models coupling the main (...) elements involved have been presented in the literature. In this paper, a new model of the CVS, representing the ventricles, the circulatory system and the regulation of the CVS activity by the ANS, is presented. The models of the vascular system and the ventricular activity have been developed using the Bond Graph formalism, as it proposes a unified representation for all energetic domains, facilitating the integration of mechanic and hydraulic phenomena. In order to take into account the electro-mechanical behaviour of both ventricles, an electrophysiologic model of the cardiac action potential, represented by a set of ordinary differential equations, has been integrated. The short-term ANS regulation of heart rate, cardiac contractility and peripheral vasoconstriction is represented by means of continuous transfer functions. These models, represented in different continuous formalisms, are coupled by using a multi-formalism simulation library. Results are presented for two different autonomic tests, namely the Tilt Test and the Valsalva Manoeuvre, by comparing real and simulated signals. (shrink)

The study of the autonomic nervous system (ANS) function has shown to provide useful indicators for risk stratification and early detection on a variety of cardiovascular pathologies. However, data gathered during different tests of the ANS are difficult to analyse, mainly due to the complex mechanisms involved in the autonomic regulation of the cardiovascular system (CVS). Although model-based analysis of ANS data has been already proposed as a way to cope with this complexity, only a few models coupling the main (...) elements involved have been presented in the literature. In this paper, a new model of the CVS, representing the ventricles, the circulatory system and the regulation of the CVS activity by the ANS, is presented. The models of the vascular system and the ventricular activity have been developed using the Bond Graph formalism, as it proposes a unified representation for all energetic domains, facilitating the integration of mechanic and hydraulic phenomena. In order to take into account the electro-mechanical behaviour of both ventricles, an electrophysiologic model of the cardiac action potential, represented by a set of ordinary differential equations, has been integrated. The short-term ANS regulation of heart rate, cardiac contractility and peripheral vasoconstriction is represented by means of continuous transfer functions. These models, represented in different continuous formalisms, are coupled by using a multi-formalism simulation library. Results are presented for two different autonomic tests, namely the Tilt Test and the Valsalva Manoeuvre, by comparing real and simulated signals. (shrink)

The study of the autonomic nervous system (ANS) function has shown to provide useful indicators for risk stratification and early detection on a variety of cardiovascular pathologies. However, data gathered during different tests of the ANS are difficult to analyse, mainly due to the complex mechanisms involved in the autonomic regulation of the cardiovascular system (CVS). Although model-based analysis of ANS data has been already proposed as a way to cope with this complexity, only a few models coupling the main (...) elements involved have been presented in the literature. In this paper, a new model of the CVS, representing the ventricles, the circulatory system and the regulation of the CVS activity by the ANS, is presented. The models of the vascular system and the ventricular activity have been developed using the Bond Graph formalism, as it proposes a unified representation for all energetic domains, facilitating the integration of mechanic and hydraulic phenomena. In order to take into account the electro-mechanical behaviour of both ventricles, an electrophysiologic model of the cardiac action potential, represented by a set of ordinary differential equations, has been integrated. The short-term ANS regulation of heart rate, cardiac contractility and peripheral vasoconstriction is represented by means of continuous transfer functions. These models, represented in different continuous formalisms, are coupled by using a multi-formalism simulation library. Results are presented for two different autonomic tests, namely the Tilt Test and the Valsalva Manoeuvre, by comparing real and simulated signals. (shrink)

A central claim in stakeholder theory is that, if we see stakeholders as human beings, we will attribute higher moral standing or show more moral consideration to stakeholders. But would the same hold for firms? In this paper, I apply the concepts of humanization and moral standing to firms, and I predict that individuals attribute higher moral standing to stakeholder-oriented than to profit-oriented firms, because individuals attribute more experience to stakeholder-oriented than to profit-oriented firms. Five experiments support these predictions across (...) different operationalizations of stakeholder and profit orientations. The analyses show that moral standing attributions are not fully explained by attributions of agency to firms, or by attributions of experience or agency to human stakeholders. By unearthing the importance of experience attributions for moral standing attributions to firms, this work provides novel insights in ongoing legal, philosophical and public debates related to firms’ moral standing. The findings also bring the debate about firms’ moral standing to the heart of stakeholder theory, and lead to new normative and descriptive research questions about the interests of firms and their stakeholders. (shrink)

While leading through goals is usually associated with a task-oriented leadership style, the present work links goal setting to transformational leadership. A longitudinal field study was conducted to investigate the influence of transformational leadership on followers’ job satisfaction, organizational commitment, and proactive behavior via goal attributes. Findings indicate that transformational leaders influence the extent to which followers evaluate organizational goals as important and perceive them as attainable. Multiple mediation analysis revealed that these goal attributes transmit the effect of transformational leadership (...) on followers’ job attitudes and proactive behavior. However, goal importance and goal attainability seem to be of differential importance for the different outcomes. (shrink)

This is the editorial for the special issue 'Systems Thinking, Spirituality and Wisdom: Perspectives on Ken Wilber'.

Health care workers with needlestick exposures to patients' blood often request a test of the patient for evidence of infection with human immunodeficiency virus. If the patient refuses the test, a conflict develops between the interests of the health care worker and those of the patient. Traditional approaches to this dilemma attempt to balance the rights or utilities of abstract patients and health care workers. While these approaches have the advantage of offering clear guidelines in advance of conflict, the interests (...) of the actual participants may differ from those used to create the guidelines. In nonmedical settings, conflicts are often resolved efficiently through negotiation and monetary exchanges. Although negotiated monetary settlements between health care workers and patients may be an impractical way to resolve medical conflicts, models developed from these perspectives provide insights into the individual interests of physicians and patients. Changing existing rules about medical record documentation, or increasing the penalties for the misuse of medical information, may satisfy the interests on both sides of the conflict and so represent integrative bargaining solutions. Even so, as the relationship between health care workers and their patients evolves, more explicit strategies for negotiation may become a reasonable solution to the problem of conflict. (shrink)

This paper is devoted to the study of some subvarieties of the variety Qof Q-Heyting algebras, that is, Heyting algebras with a quantifier. In particular, a deeper investigation is carried out in the variety Q 3 of three-valued Q-Heyting algebras to show that the structure of the lattice of subvarieties of Qis far more complicated that the lattice of subvarieties of Heyting algebras. We determine the simple and subdirectly irreducible algebras in Q 3 and we construct the lattice of subvarieties (...) (Q 3 ) of the variety Q 3. (shrink)

In earlier work we have described how computer algebra may be used to derive composite rate laws for complete systems of equations, using the mathematical technique of Gröbner Bases (Bennett, Davenport and Sauro, 1988). Such composite rate laws may then be fitted to experimental data to yield estimates of kinetic parameters.Recently we have been investigating the practical application of this methodology to the estimation of kinetic parameters for the closed two enzyme system of aspartate aminotransferase (AAT) and malate dehydrogenase (MDH) (...) (Fisher 1990a; Fisher 1990b; Bennett and Fisher, 1990). (shrink)

This volume focuses on the modeling of cognition, and brings together contributions from psychologists and researchers in the field of cognitive science.

The aim of this paper is to investigate the variety of symmetric closure algebras, that is, closure algebras endowed with a De Morgan operator. Some general properties are derived. Particularly, the lattice of subvarieties of the subvariety of monadic symmetric algebras is described and an equational basis for each subvariety is given.