Properties sometimes attributed to the “particle” aspect of a neutron, e.g., mass and magnetic moment, cannot straightforwardly be regarded in the Bohm interpretation of quantum mechanics as localized at the hypothetical position of the particle. This is shown by examining a series of effects in neutron interferometry. A related thought-experiment also provides a variation of a recent demonstration that which-way detectors can appear to behave anomolously in the Bohm theory.

Integrating concepts of maintenance and of origins is essential to explaining biological diversity. The unified theory of evolution attempts to find a common theme linking production rules inherent in biological systems, explaining the origin of biological order as a manifestation of the flow of energy and the flow of information on various spatial and temporal scales, with the recognition that natural selection is an evolutionarily relevant process. Biological systems persist in space and time by transfor ming energy from one state (...) to another in a manner that generates structures which allows the system to continue to persist. Two classes of energetic transformations allow this; heat-generating transformations, resulting in a net loss of energy from the system, and conservative transformations, changing unusable energy into states that can be stored and used subsequently. All conservative transformations in biological systems are coupled with heat-generating transformations; hence, inherent biological production, or genealogical proesses, is positively entropic. There is a self-organizing phenomenology common to genealogical phenomena, which imparts an arrow of time to biological systems. Natural selection, which by itself is time-reversible, contributes to the organization of the self-organized genealogical trajectories. The interplay of genealogical (diversity-promoting) and selective (diversity-limiting) processes produces biological order to which the primary contribution is genealogical history. Dynamic changes occuring on times scales shorter than speciation rates are microevolutionary; those occuring on time scales longer than speciation rates are macroevolutionary. Macroevolutionary processes are neither redicible to, nor autonomous from, microevolutionary processes. (shrink)

Diogenes Laertius relates the tale that Aristotle, upon being reproached for giving alms to a debased fellow, replied, ‘It was not his character, but the man, that I pitied.’ Some such reply is equally apt in apology for a paper paying homage to an idea long discredited in the philosophical world, Aristotle's theory of Place. I have been moved, not indeed by the apparent character of Aristotle's theory, for that is easily reproached, but by what has proved for the philosophical (...) tradition of infinite worth, what we may call the theory's ‘latent virtue’. There is a danger, of course, as hard-headed philologists and commentators are always reminding us, that in attending to this latent virtue we may be paying sentimental homage to the dead. Thus it will be important that we first carefully and coldly examine the overt character of the Aristotelian doctrine before attempting to justify any philosophical compassion felt in its presence. More than likely in such a disinterested inquiry it will be found that our ‘debased fellow’ is a good deal more of a man than the modern reformers have allowed. (shrink)

Rita Bottino,1 Santosh Nagaraju,2 Vikas Satyananda,2 Hidetaka Hara,2 Martin Wijkstrom,2 Massimo Trucco,1 David KC Cooper2 1Institute of Cellular Therapeutics, Allegheny Health Network, 2Thomas E Starzl Transplantation Institute, Department of Surgery, University of Pittsburgh, Pittsburgh, PA, USA: Diabetes mellitus is increasing worldwide. Type 1 diabetes can be treated successfully by islet allotransplantation, the results of which are steadily improving. However, the number of islets that can be obtained from deceased human donors will never be sufficient to cure more than a very (...) small percentage of patients who might benefit from transplantation. Although there are some differences in glucose metabolism between pigs and humans, the use of pigs could provide an unlimited supply of islets, and the insulin produced would undoubtedly control glucose levels. Transplantation of islets into the portal vein results in islets residing in the liver; however, an early inflammatory response and rejection remain problematic, even when the recipient is receiving immunosuppressive therapy. In the long term, immunosuppressive drugs may exhibit toxicities to patients and specifically harm the islet cells. In contrast, encapsulation techniques provide islets with a physical barrier that prevents antibodies binding to the islet graft while still allowing insulin to be released into the recipient's circulation; in theory, patients receiving encapsulated grafts might not require exogenous immunosuppressive therapy. Nonhuman primates with encapsulated pig islet transplants have remained insulin-independent for several weeks, but long-term efficacy remains uncertain. Furthermore, techniques are now available to knock out genes from the pig and/or insert human genes, thus rendering the antigenic structure of pigs closer to that of humans, and providing protection from the human immune response. Islet transplantation from genetically engineered pigs has been followed by insulin independence in a small number of nonhuman primates for greater than 1 year. Neonatal islets have some advantages over adult islets in that they are easier to isolate and culture, and have the ability to proliferate during the first few months after transplantation. In 2009, the International Xenotransplantation Association set up a group to encourage and advise on clinical trials of pig islet xenotransplantation; this group's guidelines are discussed. Clinical trials of encapsulated pig islets are already under way. Keywords: diabetes, islets, pancreatic, pig, xenotransplantation. (shrink)

The famous passage in which Plotinus declares that fine art, so far from simply reproducing nature, ‘goes back to the Reason-principles from which nature herself emanates,’ has hitherto been generally regarded as a tacit criticism of Plato's teaching, and as an original contribution to the philosophy of art involving a rupture with the entire previous tradition of Greek aesthetic theory. Yet Plotinus introduces it, not as if he were proclaiming a new gospel, but almost casually, as a subordinate link in (...) his discussion of Intelligible Beauty. And though his respect for Plato was not the half-superstitious reverence of the later Neoplatonists, he was at all times more zealous to walk in Plato's footsteps than to correct or criticize him, tacitly or otherwise. Moreover, can it be said with certainty that his doctrine is in itself opposed to Plato's? That question can be answered only by a detailed examination of Plato's theory of art—a task which I hope to accomplish elsewhere. In the present article, postponing all enquiry into the relation between these two aesthetic theories, I shall endeavour to show that the teaching of Plotinus was not a sudden innovation, but the natural and indeed inevitable outcome of preceding thought. (shrink)