Heterotopic Heart Transplantation

The heterotopic heart transplant was pioneered by Christian Barnard in the late 1970s as a way to treat acute rejection in the pre-cyclosporine era. The technique was also used for the treatment of severe pulmonary hypertension, in patients unable to have an orthotopic heart transplant. Some surgeons have used the heterotopic heart transplant as a way to increase the donor heart pool around the world in more recent years. The heterotopic heart transplant is a good viable option for severe pulmonary hypertension patients, and, severe pulmonary vascular resistance patients, who would otherwise, not qualify for an orthotopic heart transplant. The outcomes for these recipients have been comparable to survival outcomes for similar orthotopic heart transplant recipients

The Inconceivable Popularity of Conceivability Arguments

Famous examples of conceivability arguments include (i) Descartes’ argument for mind-body dualism, (ii) Kripke's ‘modal argument’ against psychophysical identity theory, (iii) Chalmers’ ‘zombie argument’ against materialism, and (iv) modal versions of the ontological argument for theism. In this paper, we show that for any such conceivability argument, C, there is a corresponding ‘mirror argument’, M. M is deductively valid and has a conclusion that contradicts C's conclusion. Hence, a proponent of C—henceforth, a ‘conceivabilist’—can be warranted in holding that C's premises are conjointly true only if she can find fault with one of M's premises. But M's premises are modelled on a pair of C's premises. The same reasoning that supports the latter supports the former. For this reason, a conceivabilist can repudiate M's premises only on pain of severely undermining C's premises. We conclude on this basis that all conceivability arguments, including each of (i)–(iv), are fallacious

The Declining Role of Private Defined Benefit Pension Plans: Who is Affected, and How

This chapter analyzes the impact of future freezes among corporate defined benefit (DB) pension plans. We simulate the impact on expected future pension wealth by assuming all existing private DB plans immediately freeze accruals for new employees. While this indicates the potential reduction in retirement wealth attributable to such plans, it does not recognize that sponsors freezing accruals may increase employer contributions to existing defined contribution (DC) plans or establish new DC plans. Using an empirical distribution of enhanced contributions to DC plans from sponsors freezing their DB plans, we simulate the nominal annuity that could be purchased at retirement age from these enhanced contributions. We then back out the net pension loss experienced by employees in the future

The Turing Guide

This volume celebrates the various facets of Alan Turing (1912–1954), the British mathematician and computing pioneer, widely considered as the father of computer science. It is aimed at the general reader, with additional notes and references for those who wish to explore the life and work of Turing more deeply. The book is divided into eight parts, covering different aspects of Turing’s life and work. Part I presents various biographical aspects of Turing, some from a personal point of view. Part II presents Turing’s universal machine (now known as a Turing machine), which provides a theoretical framework for reasoning about computation. His 1936 paper on this subject is widely seen as providing the starting point for the field of theoretical computer science. Part III presents Turing’s working on codebreaking during World War II. While the War was a disastrous interlude for many, for Turing it provided a nationally important outlet for his creative genius. It is not an overstatement to say that without Turing, the War would probably have lasted longer, and may even have been lost by the Allies. The sensitive nature of Turning’s wartime work meant that much of this has been revealed only relatively recently. Part IV presents Turing’s post-War work on computing, both at the National Physical Laboratory and at the University of Manchester. He made contributions to both hardware design, through the ACE computer at the NPL, and software, especially at Manchester. Part V covers Turing’s contribution to machine intelligence (now known as Artificial Intelligence or AI). Although Turing did not coin the term, he can be considered a founder of this field which is still active today, authoring a seminal paper in 1950. Part VI covers morphogenesis, Turing’s last major scientific contribution, on the generation of seemingly random patterns in biology and on the mathematics behind such patterns. Interest in this area has increased rapidly in recent times in the field of bioinformatics, with Turing’s 1952 paper on this subject being frequently cited. Part VII presents some of Turing’s mathematical influences and achievements. Turing was remarkably free of external influences, with few co-authors – Max Newman was an exception and acted as a mathematical mentor in both Cambridge and Manchester. Part VIII considers Turing in a wider context, including his influence and legacy to science and in the public consciousness. Reflecting Turing’s wide influence, the book includes contributions by authors from a wide variety of backgrounds. Contemporaries provide reminiscences, while there are perspectives by philosophers, mathematicians, computer scientists, historians of science, and museum curators. Some of the contributors gave presentations at Turing Centenary meetings in 2012 in Bletchley Park, King’s College Cambridge, and Oxford University, and several of the chapters in this volume are based on those presentations – some through transcription of the original talks, especially for Turing’s contemporaries, now aged in their 90s. Sadly, some contributors died before the publication of this book, hence its dedication to them. For those interested in personal recollections, Chapters 2, 3, 11, 12, 16, 17, and 36 will be of interest. For philosophical aspects of Turing’s work, see Chapters 6, 7, 26–31, and 41. Mathematical perspectives can be found in Chapters 35 and 37–39. Historical perspectives can be found in Chapters 4, 8, 9, 10, 13–15, 18, 19, 21–25, 34, and 40. With respect to Turing’s body of work, the treatment in Parts II–VI is broadly chronological. We have attempted to be comprehensive with respect to all the important aspects of Turing’s achievements, and the book can be read cover to cover, or the chapters can be tackled individually if desired. There are cross-references between chapters where appropriate, and some chapters will inevitably overlap. We hope that you enjoy this volume as part of your library and that you will dip into it whenever you wish to enter the multifaceted world of Alan Turing

AI's Promise: Our post-human future

In celebration of the centenary of Alan Turing’s birth, and motivated by the possibility of living forever in a cyborg body, we’ve given this forum over to refl ection on the future of machine intelligence. Turing is rightly called the father of computing, but just what did he accomplish, and what is his legacy? We begin to answer these questions with a rousing bit of speculation (and calls for restraint) by Jack Copeland and Diane Proudfoot, who consider the real promise of artifi cial intelligence. Next, John Preston gives us pause with an argument for the view that, Turing’s enthusiasm notwithstanding, computers will never really be thinking things. The famous Turing Test for machine intelligence gets a lot of attention, but Georges Rey argues that it’s small fry compared to Turing’s lesser known and much more profound ideas. Selmer Bringsjord and Joe Johnson warn of social upheaval ahead, owed to advances in robotics. We conclude with Luciano Floridi’s thoughts not just on Turing, but on the information revolution we fi nd ourselves in. Perhaps Turing’s ideas are transforming our conception of the universe and our place in it, in ways we have yet to understand fully. Floridi argues that Turing is still with us, and his legacy is very much alive.In celebration of the centenary of Alan Turing’s birth, and motivated by the possibility of living forever in a cyborg body, we’ve given this forum over to refl ection on the future of machine intelligence. Turing is rightly called the father of computing, but just what did he accomplish, and what is his legacy? We begin to answer these questions with a rousing bit of speculation (and calls for restraint) by Jack Copeland and Diane Proudfoot, who consider the real promise of artifi cial intelligence. Next, John Preston gives us pause with an argument for the view that, Turing’s enthusiasm notwithstanding, computers will never really be thinking things. The famous Turing Test for machine intelligence gets a lot of attention, but Georges Rey argues that it’s small fry compared to Turing’s lesser known and much more profound ideas. Selmer Bringsjord and Joe Johnson warn of social upheaval ahead, owed to advances in robotics. We conclude with Luciano Floridi’s thoughts not just on Turing, but on the information revolution we fi nd ourselves in. Perhaps Turing’s ideas are transforming our conception of the universe and our place in it, in ways we have yet to understand fully. Floridi argues that Turing is still with us, and his legacy is very much alive

Cardiac transplantation in patients over 50 years of age

Sixty-two patients underwent cardiac transplantation at the University of Arizona from March 1979 to March 1985. Thirteen patients (11 men and 2 women) were over 50 years of age at the time of transplantation and 49 were under the age of 50. The mean age (± SEM) of the patients over 50 was 53 ± 1 years. Eight of these patients were treated with conventional immunosuppressive therapy (azathioprine, prednisone and rabbit antithymocyte globulin) and Ave, beginning in January 1983, were treated with cyclosporine, prednisone and rabbit antithymocyte globulin.Early mortality (0 to 90 days) was 16% in the group over 50 versus 18% for those under 50. The late mortality (> 90 days) was 36 and 33%, respectively. In both groups, rejection and infection were the principal causes of death. The incidence of infection was 1.9 ± 0.5 episodes per patient in those patients over 50 and 1.9 ± 0.4 in those under 50. The incidence of rejection was 1.3 episodes per patient-year in patients over 50 and 1.7 episodes per patient-year in those under 50. Actuarial survival at 1 year was 72 ± 14% in the group over 50 and 66 ± 7% in the group under 50 years of age.These data indicate that the results of cardiac transplantation for patients over 50 do not differ significantly from those for patients under 50. Therefore, it is concluded that a rigidly defined age criterion for cardiac transplant recipients is not acceptable. Each potential recipient must be evaluated in terms of individual risk and benefit from the procedure

The Indeterminacy of Computation

Do the dynamics of a physical system determine what function the system computes? Except in special cases, the answer is no: it is often indeterminate what function a given physical system computes. Accordingly, care should be taken when the question ‘What does a particular neural system do?’ is answered by hypothesising that the system computes a particular function. The phenomenon of the indeterminacy of computation has important implications for the development of computational explanations of biological systems. Additionally, the phenomenon lends some support to the idea that a single neural structure may perform multiple cognitive functions, each subserved by a different computation. We provide an overarching conceptual framework in order to further the philosophical debate on the nature of computational indeterminacy and computational explanation