In 1885, during initial discussions of J. C. Maxwell's celebrated thermodynamic demon, Whiting (1) observed that the demon-like velocity selection of molecules can occur in a gravitationally bound gas. Recently, a gravitational Maxwell demon has been proposed which makes use of this observation [D. P. Sheehan, J. Glick, and J. D. Means, Found. Phys. 30, 1227 (2000)]. Here we report on numerical simulations that detail its microscopic phase space structure. Results verify the previously hypothesized mechanism of its paradoxical behavior. (...) This system appears to be the only example of a fully classical mechanical Maxwell demon that has not been resolved in favor of the second law of thermodynamics. (shrink)

A laboratory-testable, solid-state Maxwell demon is proposed that utilizes the electric field energy of an open-gap p-n junction. Numerical results from a commercial semiconductor device simulator (Silvaco International–Atlas) verify primary results from a 1-D analytic model. Present day fabrication techniques appear adequate for laboratory tests of principle.

In 2000, a simple, foundational thermodynamic paradox was proposed: a sealed blackbody cavity contains a diatomic gas and a radiometer whose apposing vane surfaces dissociate and recombine the gas to different degrees (A $_{2} \rightleftharpoons $ 2A). As a result of differing desorption rates for A and A $_{2}$ , there arise between the vane faces permanent pressure and temperature differences, either of which can be harnessed to perform work, in apparent conflict with the second law of thermodynamics. Here we (...) report on the first experimental realization of this paradox, involving the dissociation of low-pressure hydrogen gas on high-temperature refractory metals (tungsten and rhenium) under blackbody cavity conditions. The results, corroborated by other laboratory studies and supported by theory, confirm the paradoxical temperature difference and point to physics beyond the traditional understanding of the second law. (shrink)

Two categories of life are currently recognized—chemosynthetic and photosynthetic—indicating their principal free energy resource as either chemicals or electromagnetic radiation. Building on recent developments in thermodynamics, we posit a third category of life—thermosynthetic life (TL)—which relies on environmental heat rather than traditional free energy sources. Since thermal energy is more abundant than chemicals or light in many settings, thermosynthesis offers compelling evolutionary possibilities for new life forms. Based on variants of standard cellular machinery, a physical model is proposed for the (...) conversion of thermal energy into biochemical work. Conditions favorable to thermosynthetic life and prospects for its discovery are assessed. Terrestrially, deep-subsurface unicellular anaerobic superthermophiles are deduced to be likely TL candidates. (shrink)

In 1885, during initial discussions of J. C. Maxwell's celebrated thermodynamic demon, Whiting(1) observed that the demon-like velocity selection of molecules can occur in a gravitationally bound gas. Recently, a gravitational Maxwell demon has been proposed which makes use of this observation [D. P. Sheehan, J. Glick, and J. D. Means, Found. Phys. 30, 1227 (2000)]. Here we report on numerical simulations that detail its microscopic phase space structure. Results verify the previously hypothesized mechanism of its paradoxical behavior. This (...) system appears to be the only example of a fully classical mechanical Maxwell demon that has not been resolved in favor of the second law of thermodynamics. (shrink)

Over the last 10–15 years the second law of thermodynamics has undergone unprecedented scrutiny, particularly with respect to its universal status. This brief article introduces the proceedings of a recent symposium devoted to this topic, The second law of thermodynamics: Foundations and Status, held at University of San Diego as part of the 87th Annual Meeting of the Pacific Division of the AAAS (June 19–22, 2006). The papers are introduced under three themes: ideal gases, quantum perspectives, and interpretation. Roughly half (...) the papers support traditional interpretations of the second law while the rest challenge it. (shrink)

A new member of a growing class of unresolved second law paradoxes is examined.(1–7) In a sealed blackbody cavity, a spherical gravitator is suspended in a low density gas. Infalling gas suprathermally strikes the gravitator which is spherically asymmetric between its hemispheres with respect to surface trapping probability for the gas. In principle, this system can be made to perform steady-state work solely at the expense of heat from the heat bath, this in apparent violation of the second law of (...) thermodynamics. Detailed three-dimensional test particle simulations of this system support this prediction. Standard resolutions to the paradox are discussed and found to be untenable. Experiments corroborating a central physical process of the paradox are discussed briefly. The paradox is discussed in the context of the Maxwell demon. (shrink)

Peter Abelard (1079–1142 ce) was the most wide‐ranging philosopher of the twelfth century. He quickly established himself as a leading teacher of logic in and near Paris shortly after 1100. After his affair with Heloise, and his subsequent castration, Abelard became a monk, but he returned to teaching in the Paris schools until 1140, when his work was condemned by a Church Council at Sens. His logical writings were based around discussion of the “Old Logic”: Porphyry's Isagoge, aristotle'S Categories and (...) On Interpretation and boethius'S textbook on topical inference. They comprise a freestanding Dialectica (“Logic”; probably c.1116), a set of commentaries (known as the Logica [Ingredientibus], c. 1119) and a later (c. 1125) commentary on the Isagoge (Logica Nostrorum Petititoni Sociorum or Glossulae). In a work Abelard called his Theologia, issued in three main versions (between 1120 and c.1134), he attempted a logical analysis of trinitarian relations and explored the philosophical problems surrounding God's claims to omnipotence and omniscience. The Collationes (“Debates,” also known as “Dialogue between a Christian, a Philosopher and a Jew”; probably c.1130) present a rational investigation into the nature of the highest good, in which the Christian and the Philosopher (who seems to be modeled on a philosopher of pagan antiquity) are remarkably in agreement. The unfinished Scito teipsum (“Know thyself,” also known as the “Ethics”; c.1138) analyses moral action. (shrink)

The most‐critical point of reproductive development in all sexually reproducing species is the transition from mitotic to meiotic cell cycle. Studies in unicellular fungi have indicated that the decision to enter meiosis must be made before the beginning of the premeiotic S phase. Recent data from the mouse1 suggest that this timing of meiosis initiation is a universal feature shared also by multicellular eukaryotes. In contrast, the signaling cascade that leads to meiosis initiation shows great diversity among species. BioEssays 29:511–514, (...) 2007. © 2007 Wiley Periodicals, Inc. (shrink)

Many medical ethicists accept the thesis that there is no moral difference between withholding and withdrawing life-sustaining therapy. In this paper, we offer an interesting counterexample which shows that this thesis is not always true. Withholding is distinguished from withdrawing by the simple fact that therapy must have already been initiated in order to speak coherently about withdrawal. Provided that there is a genuine need and that therapy is biomedically effective, the historical fact that therapy has been initiated entails a (...) claim to continue therapy that cannot be attributed to patients who have not yet received therapy. This intrinsic difference between withholding and withdrawing therapy is of moral importance. In many instances, patients will waive this claim. But when one considers withdrawing therapy from one patient to help another in a setting of scarce resources, this intrinsic moral difference comes into sharp focus. In an era of shrinking medical resources, this difference cannot be ignored. (shrink)

Traditional epistemic and doxastic logics cannot deal with inconsistent beliefs nor do they represent the evidence an agent possesses. So-called ‘evidence logics’ have been introduced to deal with both of those issues. The semantics of these logics are based on neighbourhood or hypergraph frames. The neighbourhoods of a world represent the basic evidence available to an agent. On one view, beliefs supported by evidence are propositions derived from all maximally consistent collections evidence. An alternative concept of beliefs takes them to (...) be propositions derivable from consistent partitions of one’s inconsistent evidence; this is known as Schotch-Jennings Forcing. This paper develops a modal logic based on the hypergraph semantics to represent Schotch-Jennings Forcing. The modal language includes an operator U(φ1,…,φn;ψ)\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$U(\varphi _1, \ldots, \varphi _n;\psi )$$\end{document} which is similar to one introduced in Instantial Neighbourhood Logic. It is of variable arity and the input formulas enjoy distinct roles. The U operator expresses that all evidence at a particular world that supports ψ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\psi $$\end{document} can be supported by at least one of the φi\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varphi _i$$\end{document}s. U can then be used to express that all the evidence available can be unified by the finite set of formulas φ1,…,φn\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\varphi _1,\ldots, \varphi _n$$\end{document} if ψ\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\psi $$\end{document} is taken to be ⊤\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\top $$\end{document}. Future developments will then use that semantics as the basis for a doxastic logic akin to evidence logics. (shrink)

Recent studies in semantics of modal and superintuitionistic predicate logics provided many examples of incompleteness, especially for Kripke semantics. So there is a problem: to find an appropriate possible- world semantics which is equivalent to Kripke semantics at the propositional level and which is strong enough to prove general completeness results. The present paper introduces a new semantics of Kripke metaframes' generalizing some earlier notions. The main innovation is in considering "n"-tuples of individuals as abstract "n"-dimensional vectors', together with some (...) transformations of these vectors. Soundness of the semantics is proved to be equivalent to some non- logical properties of metaframes; and thus we describe the maximal semantics of Kripke- type. (shrink)

OBJECTIVE: To examine the long-term effects of an innovative curriculum on medical house officers' (HOs') knowledge, confidence, and attitudes regarding medical ethics. DESIGN: Long term cohort study. The two-year curriculum, implemented by a single physician ethicist with assistance from other faculty, was fully integrated into the programme. It consisted of monthly sessions: ethics morning report alternating with didactic conferences. The content included topics such as ethics vocabulary and principles, withdrawing life support, informed consent, and justice. Identical content was offered simultaneously (...) at the largest affiliated community hospital. SETTING: A multi-hospital university training programme from July, 1992 to June, 1994. PARTICIPANTS: Thirty-nine HOs responded in 92. Thirty HOs from the same cohort responded in 94 (response rates = 83% v 71%; P = 0.19). RESULTS: The curriculum was well received, with 96% of HOs finding the sessions stimulating. Previously validated scales of knowledge and confidence were administered at baseline and at follow-up. The average knowledge score improved 14% (P < 0.001). Confidence also improved, rising from 3.3 to 3.8 on a 5-point Likert scale (P < 0.001). These findings were independent of age, gender, religion, and prior education. The only attitudinal change was an increase in the proportion of residents who thought that ethics should be a required part of residency training (57% v 80%, P = 0.05). CONCLUSION: This curriculum appears practical, popular, and effective. It should be readily transferable to other institutions. (shrink)

We report the results of a randomized trial to assess the impact of an innovative ethics curriculum on the knowledge and confidence of 85 medical house officers in a university hospital programme, as well as their responses to a simulated clinical case. Twenty-five per cent of the house officers received a lecture series, 25 per cent received lectures and case conferences, with an ethicist in attendance, and 50 per cent served as controls. A post-intervention questionnaire was administered. Knowledge scores did (...) not differ among the groups. Confidence regarding ethical issues was significantly greater in the aggregate intervention group compared to the control group. Confidence regarding procedural issues related to ethics was significantly higher for the EI group than for the controls. Responses to a simulated case showed that significantly fewer house officers in the EI group would intubate a patient for whom such therapy would be futile. We conclude that ethics education can have an impact on house officers' confidence and their responses to a simulated case, and that the EI was more effective than the LI. Such results have implications regarding the implementation of ethics education during residency. (shrink)

In any competition for monuments of wasted labour the collection of accidental acrostics in Latin poets published by I. Hilberg would stand a good chance of a prize. But amongst his examples of ‘neckische Spiele des Zufalls’ is one I am gullible enough to believe may be more significant. In Aeneid 7. 601–15 Vergil describes the custom of opening the gates of war in a long anacoluthic sentence, the first four lines of which run: Mos erat Hesperio in Latio, quern (...) protinus urbes Albanae coluere sacrum, nunc maxima rerum Roma colit, cum prima movent in proelia Mortem, Sive Getis inferre manu lacrimabile bellum…. (shrink)

In a recent article in this journal our unit was accused of a number of errors of judgment in applying covert video surveillance (CVS) to infants and children suspected of life-threatening abuse. The article implied, that on moving from the Royal Brompton Hospital in London to North Staffordshire Hospital, we failed to present our work to the Research Ethics Committee (REC). We did send our protocol to the REC though we did not consider that, after a total of 16 patients (...) had been documented as being the subject of life-threatening abuse, this was research. The REC in Staffordshire agreed with us. We were also accused of undertaking work that should be pursued by the Police. We agree with this. However, unlike the Metropolitan Police the Staffordshire Police would not undertake CVS. We fail to agree that 'working together' with parents is necessarily practical or safe when trying to protect children from life-threatening abuse of this kind. (shrink)

First published in 1966. Professor Dryer has furnished a highly illuminating account of Kant’s _Critique of Pure Reason _by unfolding its central argument. _Kant’s Solution for Verification in Metaphysics _brings out the light which Kant has to throw on central topics of philosophy. It takes its place as an indispensable guide to every student of the _Critique of Pure Reason. _.

First published in 1966. Professor Dryer has furnished a highly illuminating account of Kant’s _Critique of Pure Reason _by unfolding its central argument. _Kant’s Solution for Verification in Metaphysics _brings out the light which Kant has to throw on central topics of philosophy. It takes its place as an indispensable guide to every student of the _Critique of Pure Reason. _.

Originally published in 1936, this book presents the ancient Greek text of the paraphrases and quotations of Zeno's philosophical arguments, together with a facing-page English translation and editorial commentary. Detailed notes are incorporated throughout and a bibliography is also included. This book will be of value to anyone with an interest in Zeno and ancient philosophy.