We give an introduction to Turing categories, which are a convenient setting for the categorical study of abstract notions of computability. The concept of a Turing category first appeared in the work of Longo and Moggi; later, Di Paolo and Heller introduced the closely related recursion categories. One of the purposes of Turing categories is that they may be used to develop categorical formulations of recursion theory, but they also include other notions of computation, such as models of combinatory logic (...) and of the lambda calculus. In this paper our aim is to give an introduction to the basic structural theory, while at the same time illustrating how the notion is a meeting point for various other areas of logic and computation. We also provide a detailed exposition of the connection between Turing categories and partial combinatory algebras and show the sense in which the study of Turing categories is equivalent to the study of PCAs. (shrink)

We apply an online optimization process based on machine learning to the production of Bose-Einstein condensates. BEC is typically created with an exponential evaporation ramp that is optimal for ergodic dynamics with two-body s-wave interactions and no other loss rates, but likely sub-optimal for real experiments. Through repeated machine-controlled scientific experimentation and observations our ’learner’ discovers an optimal evaporation ramp for BEC production. In contrast to previous work, our learner uses a Gaussian process to develop a statistical model of the (...) relationship between the parameters it controls and the quality of the BEC produced. We demonstrate that the Gaussian process machine learner is able to discover a ramp that produces high quality BECs in 10 times fewer iterations than a previously used online optimization technique. Furthermore, we show the internal model developed can be used to determine which parameters are essential in BEC creation and which are unimportant, providing insight into the optimization process of the system. (shrink)

MEDIEVAL LOGICS LAMBERT MARIE DE RIJK (ed.), Die mittelalterlichen Traktate De mod0 opponendiet respondendi, Einleitung und Ausgabe der einschlagigen Texte. (Beitrage zur Geschichte der Philosophie und Theologie des Mittelalters, Neue Folge Band 17.) Miinster: Aschendorff, 1980. 379 pp. No price stated. THE SEVENTEENTH CENTURY MARTA FATTORI, Lessico del Novum Organum di Francesco Bacone. Rome: Edizioni dell'Ateneo 1980. Two volumes, il + 543, 520 pp. Lire 65.000. VIVIAN SALMON, The study of language in 17th century England. (Amsterdam Studies in the Theory (...) and History of Linguistic Science, Series 111: Studies in theHistory of Linguistics, Volume 17.) Amsterdam: John Benjamins B.V., 1979.x + 218 pp. Dfl. 65. Theoria cum Praxi. Zum Verhaltnis von Theorie und Praxis im 17. und 18. Jahrhundert. (Akten des 111. Internationalen Leibnizkongress, Hannover, 12. bis 17.November 1977, Band 111: Logik, Erkenntnistheorie, Wissenschaftstheorie, Metaphysik, Theologie.) Wiesbaden: Franz Steiner Verlag, 1980. vii + 269 pp. DM 48. CLASSICAL AND NON-CLASSICAL LOGICS MICHAEL CLARK, The place of syllogistic in logical theory. Nottingham: University of Nottingham Press, 1980. ix + 151 pp. £3.00. A.F. PARKER-RHODES, The theory of indistinguishables. Dordrecht, Boston and London: D. Reidel Publishing Company, 1981. xvii + 216 pp. Dfl.90.00/$39.50. NICHOLAS RESCHER and ROBERT BRANDOM, The logic of inconsistency. Oxford:Basil Blackwell, 1980. x + 174 pp. f 11.50. MISCELLANEOUS J. ZELENY, The logic of Marx. Translated from the German by T. Carver. Oxford: Basil Blackwell, 1980. xcii + 247 pp. £12.50. FELIX KAUFMANN, The infinite in mathematics. Edited by Brian McGuinness. Introduction by E. Nagel. Translation from the German by Paul Foulkes. Dordrecht: Reidel, 1978. xvii + 235 pp. Dfl 85/$39.50 (cloth); Dfl 45/$19.95 (paper). PAMELA MCCORDUCK, Machines who think. San Francisco: W.H. Freeman and Company, 1979. xiv + 275 pp. $14.95. J. MITTELSTRASS (ed.), Enzyklopadie Philosophie und Wissenschaftstheorie Bd. 1 : A-G. Mannheim, Wien, Ziirich: Bibliographisches Institut, 1980. 835 pp. DM 128. (shrink)

DBS Think Tank IX was held on August 25–27, 2021 in Orlando FL with US based participants largely in person and overseas participants joining by video conferencing technology. The DBS Think Tank was founded in 2012 and provides an open platform where clinicians, engineers and researchers can freely discuss current and emerging deep brain stimulation technologies as well as the logistical and ethical issues facing the field. The consensus among the DBS Think Tank IX speakers was that DBS expanded in (...) its scope and has been applied to multiple brain disorders in an effort to modulate neural circuitry. After collectively sharing our experiences, it was estimated that globally more than 230,000 DBS devices have been implanted for neurological and neuropsychiatric disorders. As such, this year’s meeting was focused on advances in the following areas: neuromodulation in Europe, Asia and Australia; cutting-edge technologies, neuroethics, interventional psychiatry, adaptive DBS, neuromodulation for pain, network neuromodulation for epilepsy and neuromodulation for traumatic brain injury. (shrink)

J. N. Crossley [1] raised the question of whether the implication 2 + A = A ⇒ 1 + A = A is true for constructive order types (C.O.T.'s). Using an earlier definition of constructive order type, A. G. Hamilton [2] presented a counterexample. Hamilton left open the general question, however, since he pointed out that Crossley considers only orderings which can be embedded in a standard dense r.e. ordering by a partial recursive function, and that his counterexample fails to (...) meet this requirement. We resolve the question by finding a C.O.T. A which meets Crossley's requirement and such that 2 + A = A but 1 + A ≠ A. At the suggestion of A. B. Manaster and A. G. Hamilton we easily extend this construction to show that for any n ≧ 2, there is a C.O.T. A such that n + A = A but m + A ≠ A for 0 < m < n. Hence, Theorem 3 of [2] and all of its corollaries hold with the new definition of C.O.T. The construction is not difficult and requires no priority argument. The techniques are similar to those developed in [3], but no outside results are needed here. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:Book Reviews Die Megariker: Kommentierte Sammlung der Testimonien. By Klaus D~ring. (Amsterdam : Verlag B. R. Griiner N.V., 1972. Pp. xii q- 185) D~Sring has assembled the first complete collection of textual fragments concerning the Megarian philosophers of the fourth and third centuries B.c., together with a commentary. The fragments are divided by the author into four groups, each centered around one of the better-known figures of the school: (...) Euclid, Eubulides, Diodorus Cronus, Stilpo. Evidences concerning lesser-known personalities are included under the figure to whose "circle" they belonged. A fifth group of texts appears in an Anhang devoted to the sophist Bryson (often mistakenly associated with the Megarians) and his student Polyxenus. Divisions in the commentary parallel those in the text. The author also adds a stemma summarizing his conclusions about teacher-pupil relationships within the school, and there is a selective bibliography and a SteUenregister. An index, which in view of the work's organization would be helpful, is not included. Simply as a collection of texts, this is a major addition to the scholarship in its field; with the author's commentary, it is the most important work on the Megarians since Kurt von Fritz's Real-Encyclopiidie article.1 D~Sringpresents convincing evidence that some widely disseminated opinions about the school have little or no foundation. Some of his alternative views have important consequences, and not only for the history of the Megarians. DSring rejects the dates customarily assigned to the school's founder Euclid (ca. 450ca. 380), pointing out that there is actually no good evidence for them (pp. 73-74). His own figures (ca. 435-ca. 365) rely on the evidence of Plato's Theaetetus to give the year 369 as a terminus post quem for Euclid's death. The first consequence of this chronology is that the story of Euclid stealing into Athens disguised as a woman in order to avoid the anti-Megarian decree of 432 must be rejected; Dfiring feels that it is probably one of a family of tales elaborated by later writers "urn die Macht der Philosophie zu demonstrieren " (p. 74). A more important consequence is in store when this chronology is combined with a reassessment of the evidence relating to Euclid's philosophical position. D6ring rejects the traditional description of Euclid as a "neo-Eleatic" who attempted to combine a strict Parmenidean monism with Socrates' ethical views by identifying the "One" with the "Good." Following yon Fritz, he sees this as "eine ziemlich gewaltsame antike Doxographenkonstruktion" (p. 83). His own view reverses the importance of Socratic and Eleatic elements in Euclid's thought, making him "[ein] Sokratiker, der die dem Sokratischen Denken inh~ente eleatische Komponente weiterentwickelt hat" (p. 87). Together with the revision of Euclid's dates, this would appear to eliminate decisively Kr~imer's thesis that Euclid originated the "Gleichsetzung ontologischer und axiologischer Momente''e fundamental to Platonic metaphysics. First, Euclid was only a few years older than Plato (not "at least two decades," as KrOner requires); second, there is no evidence whatever that he had studied the Eleatic doctrines before meeting Socrates; and finally, the purported "Gleichsetzung" appears to be rather the work of doxographers (pp. 87-89). When we add DSring's skeptical assessment of the story of Plato's Megarian period (p. 76), there remains little evidence to support the theory that Euclid was the ultimate source of Plato'S metaphysics. The most famous achievements of the M~garians were in the sphere of logic. Here, x Suppl. V (1931), s. v. "Megariker." H. J. Kr~mer, Arete bei Platon und Aristoteles (Heidelberg, 1959), p. 506. [52H 522 HISTORY OF PHILOSOPHY Dtring's work should provide the impetus for further research; his collection of texts is much more comprehensive than anything previously available, and his commentary, although deliberately limited to an overview, at least provides a good account of the status quaestionis. The material on the paradoxes attributed to the Megarians (pp. 106-114) is particularly valuable; he gives a good conspectus of the extensive literature on the "Liar" and "sorites," and his remarks on the lesser-known paradoxes (the "Man Who Escapes Notice," the "Electra," the "Hooded... (shrink)

More than a decade after Philip P. Wiener and Frederick H. Young edited the first volume of Studies in the Philosophy of Charles Sanders Peirce, Moore and Robin have brought together a collection of essays which serves as a valuable supplement to that earlier publication. It is more than a supplement, however; it can stand on its own as a significant contribution to Peirce scholarship. Continuity with the first volume is achieved through new essays which analyze Peirce's theory of (...) belief, of habit, and of Scotistic realism—themes about which many of the earlier papers revolved. Novelty is achieved through increased emphasis on Peirce's logical and mathematical writings and on the influence of nineteenth century evolutionism upon Peirce's pragmaticism. The exploration of the latter motif in the three contributions of W. Donald Oliver, Rulon Wells, and Thomas A. Goudge is particularly noteworthy. In their Preface, Moore and Robin state that the most significant contribution of this new volume is the revelation of the extent to which Peirce was first a scientist and then a philosopher. This is a misleading characterization of the book. True, Victor F. Lenzen's "Charles S. Peirce As Astronomer" is an engaging piece. On the other hand, the bulk of the articles impress the reader with the originality and modernity of Peirce, the philosopher and Peirce, the logician. The most notable feature of this collection is the number of essays which draw parallels between dominant philosophical and logical themes found in Peirce's writings and major interests of mid-twentieth century philosophers. Impressive examples are: A. R. Turquette's "Peirce's Icons For Deductive Logic," Richard M. Martin's "On Acting On A Belief," Larry Holmes's "Prolegomena To Peirce's Philosophy Of Mind," and Richard J. Bernstein's "Peirce's Theory of Perception." In presenting the articles which constitute this volume the editors give evidence not only of the relevance of Peirce for the contemporary student of philosophy but also of the impetus which Peirce's thought has provided for creative philosophical analysis. An additional bonus for Peirce scholars are two bibliographies prepared by Max H. Fisch. One is a supplement to Arthur W. Burk's 1958 bibliography of works by C. S. Peirce. The other is a draft of a bibliography of works about C. S. Peirce.—B. G. R. (shrink)

The lambda calculus is a universal programming language. It can represent the computable functions, and such offers a formal counterpart to the point of view of functions as rules. Terms represent functions and this allows for the application of a term/function to any other term/function, including itself. The calculus can be seen as a formal theory with certain pre-established axioms and inference rules, which can be interpreted by models. Dana Scott proposed the first non-trivial model of the extensional lambda calculus, (...) known as $ D_{\infty }$, to represent the $\lambda $-terms as the typical functions of set theory, where it is not allowed to apply a function to itself. Here we propose a construction of an $\infty $-groupoid from any lambda model endowed with a topology. We apply this construction for the particular case $D_{\infty }$, and we see that the Scott topology does not provide enough information about the relationship between higher homotopies. This motivates a new line of research focused on the exploration of $\lambda $-models with the structure of a non-trivial $\infty $-groupoid to generalize the proofs of term conversion to higher-proofs in $\lambda $-calculus. (shrink)

The pbenomenon of European integration has received a great deal ofattention from political scientists in the wake of the mid-1980s 'relaunch' ofthe European Union. However, political science's theoretical consideration of West European integration has from the outset failed to include news media as a factor in EU politics. This oversight is linked to the general dismissal of the public and public debate as irrelevant to the integration project. Yet because media have several critical functions in politics - as an information-source, (...) agendasetter, and legitimator - political science treatment of the EU now needs to account for the role of news media. Turning to concepts in normative media theory, the article proposes a framework within which to consider media and suggests empirical analysis of media coverage of the European Union. Such analysis would complement political science study of the democratisation and legitimation of the EU, while acknowledging public discourse as an element crucial to the future course of European integration. (shrink)

That endogenous retrovirus (ERV) is present within the placenta of humans and other mammals has been known for the past 25 years, but the significance of this observation is still not fully understood. Much molecular biological data have emerged in recent years to support the earlier electron microscopic data on the presence of placental ERV. The evidence for ERV in animal and human placental tissue is presented, then integrated with data on the the presence of ERV in a range of (...) other tissues, in particular teratocarcinoma cells. Placental invasiveness and maternal immunosuppression are then discussed in relation to metalloproteinase secretion, the immunosuppressive potential of retroviruses, and placental growth factors, while the evidence for a functional link between placental proto‐oncogenes and trophoblast malignancy is reviewed. Finally, placental development, structure, and life span are discussed within an evolutionary context. The hypothesis that one or more ancient trophoblastic ERVs could have played a role in the evolution and divergence of all placental mammals is evaluated. BioEssays 20:307‐316, 1998. © 1998 John Wiley & Sons, Inc. (shrink)

Lectures, scientific papers, top secret wartime material, correspondence, and broadcasts are introduced and set in context by Jack Copeland, Director of the Turing Archive for the History of Computing."--Jacket.

The role of microaggressions has gained increasing philosophical attention in recent years. However, microaggressions only tell part of the story. An often-overlooked component of inequality is the uneven and unjust distribution of microaffirmations. In this paper, I give a new definition of microaffirmations as signals that a recipient belongs to some valued or high-status class. Microaffirmations can—but need not—lead individuals to gain a sense of confidence, belonging, and merit. I then explain the harms of microaffirmations, arguing that when microaffirmations are (...) distributed inequitably, they can have larger ramifications for injustice, harming some vulnerable groups more than others. In addition, microaffirmations can lead individual actors to make choices based on who gives them microaffirmations and where they receive them, and thus can have outsized influence over the direction of an individual’s life because individuals tend to migrate to where they feel valued, appreciated, and included. I then turn to solutions to the problems I raise. I argue we should attend to and attempt to rectify inequalities in microaffirmations because doing so can help ensure not just the absence of negative attention, but also that the presence of positive attention is flowing in a just and equitable way. (shrink)

Girard and Reynolds independently invented System F to handle problems in logic and computer programming language design, respectively. Viewing F in the Curry style, which associates types with untyped lambda terms, raises the questions of typability and type checking. Typability asks for a term whether there exists some type it can be given. Type checking asks, for a particular term and type, whether the term can be given that type. The decidability of these problems has been settled for restrictions and (...) extensions of F and related systems and complexity lower-bounds have been determined for typability in F, but this report is the first to resolve whether these problems are decidable for System F. This report proves that type checking in F is undecidable, by a reduction from semi-unification, and that typability in F is undecidable, by a reduction from type checking. Because there is an easy reduction from typability to type checking, the two problems are equivalent. The reduction from type checking to typability uses a novel method of constructing lambda terms that simulate arbitrarily chosen type environments. All of the results also hold for the λI-calculus. (shrink)

The sporadic nature of Alzheimer's disease argues for an environmental link that may drive AD pathogenesis; however, the triggering factors and the period of their action are unknown. Recent studies in rodents have shown that exposure to lead during brain development predetermined the expression and regulation of the amyloid precursor protein and its amyloidogenic beta-amyloid product in old age. Here, we report that the expression of AD-related genes [APP, BACE1 ] as well as their transcriptional regulator were elevated in aged (...) monkeys exposed to Pb as infants. Furthermore, developmental exposure to Pb altered the levels, characteristics, and intracellular distribution of Abeta staining and amyloid plaques in the frontal association cortex. These latent effects were accompanied by a decrease in DNA methyltransferase activity and higher levels of oxidative damage to DNA, indicating that epigenetic imprinting in early life influenced the expression of AD-related genes and promoted DNA damage and pathogenesis. These data suggest that AD pathogenesis is influenced by early life exposures and argue for both an environmental trigger and a developmental origin of AD. (shrink)