In this paper we try to answer the question whether diffusion is a possible mechanism to explain mesoderm induction in Amphibians. First the embryological data are discussed and a hypothesis for mesoderm formation is set forth. The blastula being essentially a hollow sphere, we assume that the induction mechanism in an embryo at the blastula stage can be simulated by diffusion-reaction processes on spherical surfaces. A model is constructed for the simple case when the source is held constant with respect (...) to time, the decay proportional to the concentration and the diffusion coefficient a constant, From simulation we find a (best) value for the decay constant to be 6 × 10–5/sec and for the diffusion constant to be 0.24 × 10– 6 cm2/sec. The relation between the parameters is derived from an analytic solution for the diffusion process on a spherical surface with a continuously producing point source and the concentration proportional to the decay. The form and regulative properties of the steady concentration gradient are discussed. (shrink)

Heterocyst spacing in blue -green bacteria is widely assumed to be due to a diffusible inhibitor. The inhibitor, a nitrogen-rich compound, probably glutamine, is produced via the N2-fixing enzymes of the heterocyst and in turn serves to suppress the induction of these enzymes and of the differentiation of vegetative cells to heterocysts. This simple morphogenetic mechanism operating in growing cellular filaments ofAnabaena species is investigated on the basis of a continuous and a discrete cellular model, as well as by cell-by-cell (...) simulation of the inhibitor transport. The resulting distances between heterocysts and kinetics of their production are compared with observations, and the values of physical parameters are estimated from the models. (shrink)

In this article, we explore the extraction of recursive nested structure in the processing of binary sequences. Our aim was to determine whether humans learn the higher-order regularities of a highly simplified input where only sequential-order information marks the hierarchical structure. To this end, we implemented a sequence generated by the Fibonacci grammar in a serial reaction time task. This deterministic grammar generates aperiodic but self-similar sequences. The combination of these two properties allowed us to evaluate hierarchical learning while controlling (...) for the use of low-level strategies like detecting recurring patterns. The deterministic aspect of the grammar allowed us to predict precisely which points in the sequence should be subject to anticipation. Results showed that participants’ pattern of anticipation could not be accounted for by “flat” statistical learning processes and was consistent with them anticipating upcoming points based on hierarchical assumptions. We also found that participants were sensitive to the structure constituency, suggesting that they organized the signal into embedded constituents. We hypothesized that the participants built this structure by merging recursively deterministic transitions. (shrink)

In lieu of an abstract, here is a brief excerpt of the content:A Bridge From Analysis to Action:Psychodynamic Analyses of Religion and Michael S. Hogue's American ImmanenceAJ Turner (bio)I. IntroductionThe purpose of this essay is to work constructively with Michael S. Hogue's groundbreaking American Immanence: Democracy for an Uncertain World to demonstrate how psychodynamic analyses of religion are essential theoretical allies in the fight for resilient democracy. The "revolution in mind"1 that psychodynamic approaches contribute, especially in their analyses of religion, (...) both complements and complicates socio-political theory as a whole. In the improvisational spirit of "yes-and," the goal here is not to identify and decry the failures and shortcomings of Hogue's theopolitical vision but rather to inspire the recovery of a sibling discourse—a kind of "rebirth of a forgotten alternative"2—that also draws deeply from the American immanental tradition in order to add psychodynamic depth to Hogue's timely and important analysis. Psychodynamic theories of religion shed light on how symbolic identifications, including and especially ultimate concerns, structure personal and collective experience. By engaging religion and theology sympathetically, constructively, and creatively, theorists such as Rollo May, Gordon Allport, Karen Horney, Erich Fromm, and Ernest Becker departed from the skepticism, reductionism, and dismissal that characterized psychoanalytic analyses of religion in the wake of Freud.3 Each of these figures, and especially Becker whose work will be a focus in this essay, are noteworthy interlocutors for extending Hogue's theopolitical theorizing of resilient democracy, particularly in how they drew unique inspiration from the American immanental tradition [End Page 44] in their social analyses. In this respect, they provide a more robust theorization of the psychosocial conditions of the associational ethos needed to connect Hogue's conception of resilient democracy with forms of agonistic organization and democratic activism. Briefly stated, psychodynamic approaches are a helpful bridge for connecting these proposals to strategies of organization, their impediments, and collective action.In this way, both psychodynamic analyses of religion and Hogue's theopolitical innovation insist that no revolutionary political change is possible, and certainly not of the kind or scale needed to counter our wickedly entangled global crises, without a deep engagement with theological imaginaries. They differ, however, in their theoretical aims. Whereas Hogue compellingly argues for the political upshot of a theology deriving from the American immanental tradition, psychodynamic analysts of religion focus on the function of ultimate concerns in individual and collective life. In other words, American Immanence rests on a methodology of analyzing the philosophical and theological assumptions that have contributed to our climate crises and then presenting clear and compelling articulation of an alternative paradigm meant to open up new ways of being. In contrast psychodynamic analyses leverage conceptual clarity of psychic reality for the fundamentally therapeutic aim of transformation. At their best, both approaches share what could be called an etiological orientation to ontological questions in order to provide liberative alternatives through rational understanding and clarification, but the terrain, and thus the problems they hope to mitigate in their analyses are focused differently. Extending the visual metaphor, they are different lenses highlighting different areas of the same landscape. Furthermore, it must be said that neither are sufficient in themselves, but the psychodynamic theorists of religion to be highlighted in this essay share deeply with Hogue's heading in American Immanence.II. A Problematic AssumptionIn emphasizing and attempting to explain4 the role of non-rational processes in the both individual and social processes of perception and organization of experience, psychodynamic theories confound a widely held and problematic assumption that the triumph of rational analysis is the hallmark for building the society to which we should aspire. Political theory in general, [End Page 45] especially as it has taken its cues from a rationalist legacy about the inherently liberating force of Reason, has been weighted toward an assumption that its task of exposing the mystifications of power would suffice in inspiring more "rational" and therefore necessarily equitable social organization. This speaks to the longstanding socio-political interest in "consciousness raising" tactics, which are often meant to dispel "false consciousness." It even comes across in the emphases of Deweyan pragmatists on education. Psychologists of all stripes point out that this approach... (shrink)

For many Christians, personal experiences of God provide an important ground or justification for accepting the truth of the gospel. But we are sometimes mistaken about our experiences, and followers of other religions also provide impressive testimonies to support their religious beliefs. This book explores from a philosophical and theological perspective the viability of divine encounters as support for belief in God, arguing that some religious experiences can be accepted as genuine experiences of God and can provide evidence for Christian (...) beliefs. (shrink)

A. W. Price explores the varying ways in which context is relevant to our reasoning about what to do.

Publicación compilatoria que recoge los avances que en los últimos tiempos se han producido en materia normativa sobre acceso a los recursos genéticos, en un intento por implementar los principios del Convenio sobre la Diversidad Biológica (1992).

Ludwig Wittgenstein (1889-1951) was an extraordinarily original thinker, whose influence on twentieth-century thinking far outside the bounds of philosophy alone. In this engaging Introduction, A.C. Grayling makes Wittgenstein's thought accessible to the general reader by explaining the nature and impact of Wittgenstein's views. He describes both his early and later philosophy, the differences and connections between them, and gives a fresh assessment of Wittgenstein's continuing influence on contemporary thought.

The elephant in the room -- Crabs and octopuses -- The central intelligence of a frog -- The cerebral cortex and consciousness -- Social consciousness -- Yoda and Darth: how can we find -- Consciousness in the brain? -- The hard problem and other perspectives on consciousness -- Conscious machines -- Uploading minds -- How to build visual consciousness.

The Human A Priori is a collection of essays by A. W. Moore, one of them previously unpublished and the rest all revised. These essays are all concerned, more or less directly, with something ineliminably anthropocentric in our systematic pursuit of a priori sense-making. Part I deals with the nature, scope, and limits of a priori sense-making in general. Parts II, III, and IV deal with what are often thought to be the three great exemplars of the systematic pursuit of (...) such sense-making: philosophy in the case of Part II, ethics in the case of Part III, and mathematics in the case of Part IV. Much of the attention throughout is devoted to the work of other philosophers: Kant and Wittgenstein feature prominently, and five of the essays take the form of reviews or critical notices of recent work in philosophy. But the interest in never purely exegetical. One of the lessons that emerges from the essays, either in opposition to the views of these other philosophers or by invocation of their views, is that we humans achieve nothing of real significance in philosophy, ethics, or mathematics except from a human point of view, and hence that all three of these pursuits can be said to betoken what may reasonably be called 'the human a priori'. (shrink)

In this paper, we propose a new technique for the enhancing images. It will work on removing the noise contained in the image as well as improving its contrast based on three different enhancing transforms, we commence by embedding the image into a neutrosophic domain; where the image will be mapped in three different levels, a level of trueness, a level of falseness and a level of indeterminacy. Hence, we act separately on each level using the enhancement transforms. Finally, we (...) introduce a new analysis in the field of analysis and processing of images using the neutrosophic crisp set theory via Mat lab program where has been obtained three images, which helps in a new analysis to improve and retrieve images. (shrink)