In the present study, we have demonstrated hysteresis phenomena in the excitability of single, enzymatically dissociated guinea pig ventricular myocytes. Membrane potentials were recorded with patch pipettes in the whole-cell current clamp configuration. Repetitive stimulation with depolarizing current pulses of constant cycle length and duration but varying strength led to predictable excitation (1:l) and non-excitation (1:0) patterns depending on current strength. In addition, transition between patterns depended on the direction of current intensity change and stable hysteresis loops were obtained (...) in stimulus:response pattern vs. current intensity plots in 14 cells. Increase of pulse duration and decrease of stimulation rate contributed to a reduction in hysteresis loop areas. Changes in amplitude and shape of the subthreshold responses during the transitions from one stable pattern to the other, suggested that activity led to an increase in membrane resistance, particularly in the voltage domain between resting potential, and threshold. Therefore, we modelled the dynamic behaviour of the single cells as a function of diastolic membrane resistance, using previously published analytical solutions. Numerical iteration of the analytical model equations closely reproduced the experimental hysteresis loops in both qualitative and quantitative ways. In particular, the effect of stimulation frequency on the model was similar to the experimental findings. The overall study suggests that the excitability pattern of guinea pig ventricular myocytes accounts for hysteresis and bistabilities when current intensity is allowed to fluctuate around threshold levels. (shrink)

En este artículo se examina la relación entre el pensamiento de Hegel y el de los clásicos griegos, especialmente Aristóteles, a la luz de los comentarios de Alexandre Kojève y Leo Strauss. Se advierten las dificultades de demostrar tanto la continuidad como la ruptura de Hegel con los clásicos, así como la necesidad de profundizar la investigación acerca de qué entendían estos por conceptos como el ser, lo divino, la eternidad, lo eterno y lo trascendente. Aunque entre Hegel y los (...) clásicos se pueden apreciar diferencias claras, si consideramos ciertos matices, resulta evidente que hay una fuerte conexión entre ellos, lo cual da argumentos a favor de la afirmación de que en Hegel culmina el pensamiento clásico. (shrink)

Properties A stone, a bag of sugar and a guinea pig all weigh one kilogram. A lily, a cloud and a sample of copper sulphate are white. A statue, a dance and a mathematical equation are beautiful. The fact that distinct particular things can be the same as each other and yet different has been … Continue reading Properties →.

Structural equations have become increasingly popular in recent years as tools for understanding causation. But standard structural equations approaches to causation face deep problems. The most philosophically interesting of these consists in their failure to incorporate a distinction between default states of an object or system, and deviations therefrom. Exploring this problem, and how to fix it, helps to illuminate the central role this distinction plays in our causal thinking.

Critiques of Neoclassical Economics extend, unsurprisingly, to its mathematical structure. The discussion has largely focused on General Equilibrium Theory (GET), a formalism developed by Leon Walras over a century ago. Internally consistent, but highly unrealistic, GET lacks predictive power, and has been a historical failure. As an alternative, this article proposes a methodology largely developed by Grabner et al. (2019), in which Agent-Based Models (ABMs) are linked with existing Equation-Based Models (EBMs) as a means of developing a more powerful formalism. (...) The approach is illustrated by application to the Arrow- Debreu (AD) model of Neoclassical theory, and the Kuznets Curve of Developmental Economics. Broader implications for the social and natural sciences are briefly considered. (shrink)

In Three Guineas, first published in June, 1938 Virginia Woolf set about answering three questions. How should war be prevented? Why does the government not support education for women? Why are women prevented from engaging in professional work? Many at the time saw the matter of how best to prevent war as entirely unconnected with “women’s issues”; Woolf linked together the answers, and connected them too with discussions of such matters as social class, in what has come to be acknowledged (...) as a landmark both of feminist and of anti-war writing. Included in the first and other early editions—and integral to the work—was a series of five photographs of men of high position wearing garments that mark their status . Unlike most editions available today, this facsimile edition includes the illustrations as well as the text of the original. (shrink)

The aim of our study was to investigate the effects of a small therapeutic animal on the social behavior of nine autistic children. The social contacts of the autistic children were evaluated by a descriptive method of direct observation that was performed without and with the presence of a TA. In period one, contacts with an unfamiliar person and acquaintances were registered; in period two, contacts with the acquaintances and the TA were registered. The frequency of contacts of autistic children (...) with their acquaintances significantly increased in the presence of the TA . The frequency of contacts with the TA was significantly higher than the frequency of contacts with the UP . The form of the autistic children’s contacts with A, with the UP, and with the TA was individually dependent, and the presence of the TA changed the characteristics of contacts with A. Our results indicate that the presence of a small TA can positively influence the quantity and quality of the social behavior of autistic children and that the characteristics of social contacts were dependent on the individual. (shrink)

A logic is said to admit an equational completeness theorem when it can be interpreted into the equational consequence relative to some class of algebras. We characterize logics admitting an equational completeness theorem that are either locally tabular or have some tautology. In particular, it is shown that a protoalgebraic logic admits an equational completeness theorem precisely when it has two distinct logically equivalent formulas. While the problem of determining whether a logic admits an equational (...) completeness theorem is shown to be decidable both for logics presented by a finite set of finite matrices and for locally tabular logics presented by a finite Hilbert calculus, it becomes undecidable for arbitrary logics presented by finite Hilbert calculi. (shrink)

In 1910, Charles Richet suggested that studying individual variations in anaphylactic responses might both open a way to experimental investigation of the biological basis of individuality and help unify the immunological and physiological approaches to biological phenomena. The very opposite would happen however. In the next two decades, physiologists and immunologists interested in anaphylaxis and allergy experienced more and more difficulties in communicating. This divergence between the physiopathological and immunological approaches derived from discrepancies between the experimental systems used by each (...) of these scientific communities. Trying to develop a point of view that took into account all bodily reactions to stimuli, physiologists thought that individual variations between the laboratory animals they used (mainly dogs and cats) constituted important experimental data. Seeking to develop reproducible studies of infection, immunity and 'sensitisation', bacteriologists and immunologists considered that individual variations between the laboratory animals they used (mainly small rodents) constituted 'noise' and not a 'signal'. Each group's loyalty to the experimental models used in their discipline widened the gap between immunological and physiological explanations of allergies and led to the abandonment of studies on the biological basis of individuality. (shrink)

This paper provides a philosophical analysis of the Price equation and its role in evolutionary theory. Traditional models in population genetics postulate simplifying assumptions in order to make the models mathematically tractable. On the contrary, the Price equation implies a very specific way of theorizing, starting with assumptions that we think are true and then deriving from them the mathematical rules of the system. I argue that the Price equation is a generalization-sketch, whose main purpose is to provide a unifying (...) framework for researchers, helping them to develop specific models. The Price equation plays this role because, like other scientific principles, shows features as abstractness, unification and invariance. By underwriting this special role for the Price equation some recent disputes about it could be diverted. (shrink)

We introduce and study (weakly) semi-equational theories, generalizing equationality in stable theories (in the sense of Srour) to the NIP context. In particular, we establish a connection to distality via one-sided strong honest definitions; demonstrate that certain trees are semi-equational, while algebraically closed valued fields are not weakly semi-equational; and obtain a general criterion for weak semi-equationality of an expansion of a distal structure by a new predicate.

If patients are to be partners rather than subjects, contributing effectively to clinical research in which they have an interest, both they and investigators must change their ways. The case is argued here that the conduct of clinical research fulfils an essential need of society and that, therefore, in the interests of society, there is a moral imperative that it be done. Further essays will develop this theme, questioning along the way whether consent is a redundant concept.

This paper provides equational semantics for Dung's argumentation networks. The network nodes get numerical values in [0,1], and are supposed to satisfy certain equations. The solutions to these equations correspond to the ?extensions? of the network. This approach is very general and includes the Caminada labelling as a special case, as well as many other so-called network extensions, support systems, higher level attacks, Boolean networks, dependence on time, and much more. The equational approach has its conceptual roots in (...) the nineteenth century following the algebraic equational approach to logic by George Boole, Louis Couturat, and Ernst Schroeder. (shrink)

In a series of articles, I argue for a different relationship between investigators and subjects of clinical research – one that is based on partnership in shared aims. This would require significant behavioural change since any relationship of this nature requires each partner to recognise their duties within it. This third essay examines the duties that would fall on patients in this partnership.

This series of articles argues for a different relationship between investigators and subjects of clinical research based on partnership in shared aims and recognition, by each, of their duties within this partnership. This second essay describes how those duties arise and explores the basis on which, and by and to whom, they are owed. The conclusion that patients have duties in research raises a number of moral issues which, ultimately, question the concept of consent. Discussion of these will be continued (...) in future articles. (shrink)

This series of articles have explored the need that society has for clinical research to be done and the consequent sets of duties that call on the one hand upon investigators to carry it out and on the other upon patients to be subjects of it. The purpose of the discussions has been to understand what should be the relationship between investigators and patient-subjects in order that both might meet their obligations effectively, efficiently, safely and with mutual respect. Here I (...) reach my conclusions. (shrink)

In these articles I have so far explored the set of duties that call upon patients to participate in clinical research as subjects of it. Here I consider whether they acquire a set of rights in consequence of participation, and what these rights may be.

In the first five of these articles I have questioned the justice, and effectiveness, of total dependence in clinical research on willing volunteers. I have explored ways that might better and more equitably spread the burden of participating in clinical research as subjects of it. Here I consider this question: if consent is the barrier, must we regard consent as indispensable?

What relationship between investigators and subjects of clinical research would best meet the needs and wants of both – and of society, which has an interest not only in clinical research being done but also in its being done well? This series of articles argues that investigators and subjects should work together in a partnership based in shared aims. Other relationships are possible, however, and here I examine two.

In a series of articles, I set out my belief that investigators and subjects of research should work together in a partnership based in shared aims. Such a relationship – quite different from what is usual today – would impose duties on both partners. In earlier papers I explored the origin and nature of the duties that would fall on patients; here I examine their limits.

Recent accounts of actual causation are stated in terms of extended causal models. These extended causal models contain two elements representing two seemingly distinct modalities. The first element are structural equations which represent the or mechanisms of the model, just as ordinary causal models do. The second element are ranking functions which represent normality or typicality. The aim of this paper is to show that these two modalities can be unified. I do so by formulating two constraints under which extended (...) causal models with their two modalities can be subsumed under so called which contain just one modality. These two constraints will be formally precise versions of Lewissystem of weights or priorities” governing overall similarity between possible worlds. (shrink)

Hall [(2007), Philosophical Studies, 132, 109–136] offers a critique of structural equations accounts of actual causation, and then offers a new theory of his own. In this paper, I respond to Hall’s critique, and present some counterexamples to his new theory. These counterexamples are then diagnosed.

Presented is a completeness theorem for fuzzy equational logic with truth values in a complete residuated lattice: Given a fuzzy set Σ of identities and an identity p≈q, the degree to which p≈q syntactically follows (is provable) from Σ equals the degree to which p≈q semantically follows from Σ. Pavelka style generalization of well-known Birkhoff's theorem is therefore established.

In light of the World Anti Doping Agency’s 2013 Code Revision process, we critically explore the applicability of two of three criteria used to determine whether a method or substance should be considered for their Prohibited List, namely its (potential) performance enhancing effects and its (potential) risk to the health of the athlete. To do so, we compare two communities of human guinea pigs: (i) individuals who make a living out of serial participation in Phase 1 pharmacology trials; and (...) (ii) elite athletes who engage in what is effectively ‘unregulated clinical research’ by using untested prohibited or non-prohibited performance enhancing substances and methods, alone or in combination. Our comparison sheds light on norms of research ethics that these practices exacerbate with respect to the concepts of multiplicity, visibility, and consistency. We argue for the need to establish a proper governance framework to increase the accountability of these unregulated research practices in order to protect the human guinea pigs in elite sports contexts, and to establish reasonable grounds for the performance enhancing effects, and the risks to the health of the athlete, of the methods and substances that might justify their inclusion on the Prohibited List. (shrink)

Volume 19, Issue 9, September 2019, Page 37-39.

To find exact traveling wave solutions to nonlinear evolution equations, we propose a method combining symmetry properties with trial polynomial solution to nonlinear ordinary differential equations. By the method, we obtain some exact traveling wave solutions to the Burgers-KdV equations and a kind of reaction-diffusion equations with high order nonlinear terms. As a result, we prove that the Burgers-KdV equation does not have the real solution in the form a 0+a 1tan ξ+a 2tan 2 ξ, which indicates that some types (...) of the solutions to the Burgers-KdV equation are very limited, that is, there exists no new solution to the Burgers-KdV equation if the degree of the corresponding polynomial increases. For the second equation, we obtain some new solutions. In particular, some interesting structures in those solutions maybe imply some physical meanings. Finally, we discuss some classifications of the reaction-diffusion equations which can be solved by trial equation method. (shrink)

This is an English translation of Waldenfels' German essay: Equality and inequality are basic elements of law, justice and politics. Equality integrates each of us into a common sphere by distributing rights, duties and chances among us. Equality turns into mere indifference as far as we get overintegrated into social orders. When differences are fading away experience loses its relief and individuals lose their face. Our critical reflections start from the inevitable paradox of making equal what is not equal. In (...) various ways they refer to Nietzsche’s concept of order, to Marx’s analysis of money, to Lévinas’s ethics of the Other, and to novelists like Dostoevsky and Musil. Our critique turns against two extremes, on the one hand against any sort of normalism fixed on functioning orders, on the other hand against any sort of anomalism dreaming of mere events and permanent ruptures. Responsive phenomenology shows how we are confronted with extraordinary events. Those deviate from the ordinary and transgress its borders, without leaving the normality of our everyday world behind. The process of equalizing moves between the ordinary and the extraordinary. What makes the difference and resists mere indifference are creative responses which are to be invented again and again. (shrink)

This paper concerns modal logics of provability — Gödel-Löb systemGL and Solovay logicS — the smallest and the greatest representation of arithmetical theories in propositional logic respectively. We prove that the decision problem for admissibility of rules (with or without parameters) inGL andS is decidable. Then we get a positive solution to Friedman''s problem forGL andS. We also show that A. V. Kuznetsov''s problem of the existence of finite basis for admissible rules forGL andS has a negative solution. Afterwards we (...) give an algorithm deciding the solvability of logical equations inGL andS and constructing some solutions. (shrink)

A first-order theory is equational if every definable set is a Boolean combination of instances of equations, that is, of formulae such that the family of finite intersections of instances has the descending chain condition. Equationality is a strengthening of stability. We show the equationality of the theory of proper extensions of algebraically closed fields and of the theory of separably closed fields of arbitrary imperfection degree.

The Einstein equations can be written as Fierz-Pauli equations with self-interaction, $W\gamma _{ik} = - G_{ik} + \tfrac{1}{2}g_{ik} g^{mn} G_{mn} - k(T_{ik} - \tfrac{1}{2}g_{ik} g^{mn} T_{mn} )$ together with the covariant Hilbert-gauge condition, $(\gamma _i^h - \tfrac{1}{2}\delta _i^k g^{mn} \gamma _{mn} )_{;k} = 0$ where W denotes the covariant wave operator and G ik the Einstein tensor of the metric g ik collecting all nonlinear terms of Einstein's equations. As is known, there do not, however, exist plane-wave solutions γ ik(z)with (...) g ik Z,i Z,k=0of these equations such that what is essential to the introduction of gravitons is not satisfied in general relativity. This nonexistence corresponds with the uncertainty relation,Δp(Δg*)2(Δx)3≥h hG/ c 3 concerning the total nonlinear gravitational field g *ik =g k +γ k. (shrink)

Barut showed us how it is possible to get a Poincaré invariant n-body equation with a single time. Starting from the Barut equation for n-free particles, we show how to generalize it when they interact through Dirac oscillators with different frequencies. We then particularize the problem to n=2 and consider the particle-antiparticle system whose frequencies are respectively ω and −ω. We indicate how the resulting equation can be solved by perturbation theory, though the spectrum and its comparison with that of (...) the mesons will be given in another publication. (shrink)

Equational Boolean Relation Theory concerns the Boolean equations between sets and their forward images under multivariate functions. We study a particular instance of equational BRT involving two multivariate functions on the natural numbers and three infinite sets of natural numbers. We prove this instance from certain large cardinal axioms going far beyond the usual axioms of mathematics as formalized by ZFC. We show that this particular instance cannot be proved in ZFC, even with the addition of slightly weaker (...) large cardinal axioms, assuming the latter are consistent. (shrink)

In 1942 a coalition of twenty scientific societies formed the Conference on the Supply of Experimental Animals in an attempt to pressure the Medical Research Council to accept responsibility for the provision of standardised experimental animals in Britain. The practice of animal experimentation was subject to State regulation under the Cruelty to Animals Act of 1876, but no provision existed for the provision of animals for experimental use. Consequently, day-to-day laboratory work was reliant on a commercial small animal market which (...) had emerged to sustain the hobby of animal fancying. This paper explores how difficulties encountered in experimental practice within the laboratory led to the problematisation of biomedical science’s reliance upon a commercial market for animals during the inter-war period. This is shown to have produced a crisis within animal reliant experimental science in the early 1940s which enabled the left-wing Association of Scientific Workers to cast science’s reliance on a free market as economically inefficient and a threat to the reliability of British research. It is argued that the development of standard experimental animals in Britain was, therefore, embedded within the wider cultural, societal, political and economic national context of the time. (shrink)

We show that the equational theory of representable lower semilattice-ordered residuated semigroups is finitely based. We survey related results.