The hardware and software foundations laid in the first half of the 20th Century enabled the computing technologies that have transformed the world, but these foundations are now under siege. The current computing paradigm, which is the foundation of much of the current standards of living that we now enjoy, faces fundamental limitations that are evident from several perspectives. In terms of hardware, devices have become so small that we are struggling to eliminate the effects of thermodynamic fluctuations, which are unavoidable at the nanometer scale. In terms of software, our ability to imagine and program effective computational abstractions and implementations are clearly challenged in complex domains. In terms of systems, currently five percent of the power generated in the US is used to run computing systems - this astonishing figure is neither ecologically sustainable nor economically scalable. Economically, the cost of building next-generation semiconductor fabrication plants has soared past 10 billion. All of these difficulties - device scaling, software complexity, adaptability, energy consumption, and fabrication economics - indicate that the current computing paradigm has matured and that continued improvements along this path will be limited. If technological progress is to continue and corresponding social and economic benefits are to continue to accrue, computing must become much more capable, energy efficient, and affordable. We propose that progress in computing can continue under a united, physically grounded, computational paradigm centered on thermodynamics. Herein we propose a research agenda to extend these thermodynamic foundations into complex, non-equilibrium, self-organizing systems and apply them holistically to future computing systems that will harness nature's innate computational capacity. We call this type of computing "Thermodynamic Computing" or TC.

The great power of science lies in the ability to relate cause and effect. On the basis of the laws of gravitation, for example, eclipses can be predicted thousands of years in advance. There are other natural phenomena that are not as predictable. Although the movements of the atmosphere obey the laws of physics just as much as the movements of the planets do, weather forecasts are still stated in terms of probabilities. The weather, the flow of a mountain stream, the roll of the dice all have unpredictable aspects. Since there is no clear relation between cause and effect, such phenomena are said to have random elements. Yet until recently there was little reason to doubt that precise predictability could in principle be achieved. It was assumed that it was only necessary to gather and process a sufficient amount of information.

Submitted for the MAR10 Meeting of The American Physical Society Effects of Shape on Diffusion and Shear Flows ROBERT SHAW, NORMAN PACKARD, ProtoLife, Inc. — Diffusion of point particles is wellunderstood, likewise the motion of simple particles under shear flow. However if the particles are extended objects with shape, more complicated behavior can occur. For example, objects might enter a shaped channel in a configuration that requires them to back up a finite distance in order to proceed further. A configuration that blocks flow through the channel might be statistically preferred, an attracting metastable state of the system. In the bulk, the configuration space of a set of closely packed rigid objects can become convoluted, with many dead-end alleys. If such a system is subjected to a shear, it may naturally tend to settle in such a dead-end, and have to retrace its path in order to continue further, a configuration can become locally locked. The requirement that the system backtrack to unlock distinguishes this process from ordinary jamming, there need be no dissipation or friction per se. We have a number of computer simulations of the motions of closely packed shaped objects, under both Hamiltonian and Monte Carlo dynamics. In addition we will present a simple analytic model, describing the entry and escape of the system from the attracting locked metastable states. Robert Shaw ProtoLife, Inc Date submitted: 08 Dec 2009 Electronic form version 1.4

A concentration difference of particles across a membrane perforated by pores will induce a diffusive flux. If the diffusing objects are of the same length scale as the pores, diffusion may not be simple; objects can move into the pore in a configuration that requires them to back up in order to continue forward. A configuration that blocks flow through the pore may be statistically preferred, an attracting metastable state of the system. This effect is purely kinetic, and not dependent on potentials, friction, or dissipation. We discuss several geometries which generate this effect, and introduce a heuristic model which captures the qualitative features.

Past work has shown that ions can pass through a membrane more readily in one direction than the other. We demonstrate here in a model and an experiment that for a mixture of small and large particles such asymmetric diffusion can arise solely from an asymmetry in the geometry of the pores of the membrane. Our deterministic simulation considers a two-dimensional gas of elastic disks of two sizes diffusing through a membrane, and our laboratory experiment examines the diffusion of glass beads of two sizes through a metal membrane. in both experiment and simulation, the membrane is permeable only to the smaller particles, and the asymmetric pores lead to an asymmetry in the diffusion rates of these particles. The presence of even a small percentage of large particles can clog a membrane, preventing passage of the small particles in one direction while permitting free flow of the small particles in the other direction. The purely geometric kinetic constraints may play a role in common biological contexts such as membrane ion channels.

THE OPERATIVE TREATMENT of adult aortic stenosis is in a phase of transition. While there is general agreement that an open, visual approach is superior to closed, blind instrumentation of the valve, there can be real debate over the relative merits of debridement and incision versus artificial prosthesis. Indeed, the problems of autogenous reconstruction and homologous replacement are just appearing above the horizon, and the basic process of calcification of valvular structures is little understood. It seems worth while, therefore, to report our total experience to date with open repair of aortic stenosis in 103 adult patients. These patients represent a consecutive and, within certain limits, standardized experience. All operations were performed with the objective of restoring valvular function by deliberate, unhurried debridement and incision of accurately identified commissures, avoiding prosthetic cusp or valvular replacement wherever possible. Preliminary exploration in postmortem specimens demonstrated the feasibility of restoring function to deformed and calcified aortic valves and provided convincing evidence that this approach would be a reasonable one.1 The experience reported here, therefore, is a baseline against which the value of artificial valves can be measured and indications for their use defined. The overall clinical picture is presented in figure 1. An initial staggering mortality-10 hospital-deaths in the first 17 patients-was followed by an equally startling sequence of 23 cases without a hospital-death. Another disquieting period followed, finally leveling off so that in the last 50 cases the mortalitvI

We introduce a set of techniques for haptically manipulating digital media such as video, audio, voicemail and computer graphics, utilizing virtual mediating dynamic models based on intuitive physical metaphors. For example, a video sequence can be modeled by linking its motion to a heavy spinning virtual wheel: the user browses by grasping a physical force-feedback knob and engaging the virtual wheel through a simulated clutch to spin or brake it, while feeling the passage of individual frames. These systems were implemented on a collection of single axis actuated displays (knobs and sliders), equipped with orthogonal force sensing to enhance their expressive potential. We demonstrate how continuous interaction through a haptically actuated device rather than discrete button and key presses can produce simple yet powerful tools that leverage physical intuition.

Most haptic interfaces are designed with a desire to produce simultaneous perception across multiple senses, with haptic behaviors that complement the task at hand. However, software architectures for haptic interfaces often distribute a virtual model and tasks among multiple processes and CPUs. This functional segregation can reduce the quality of haptic experience, by hiding important details of the dynamic model and reducing the communication bandwidth between the haptic controller and the application. We present a means of closely coordinating a haptic interface with a virtual model, application content and other sensory displays. Our architecture features the ability to customize haptic behavior at a low level, in the dynamic relations among control parameters. Furthermore, we have located significant application control within the haptic process in order to facilitate effective bidirectional communication. We describe some applications for haptically manipulating dynamic media; and propose extensions to our architecture for increased generality, decreased code size and high-level programmability for efficient application development.

A detailed microscopical analysis of the morphological features that distinguish different developmental stages of nodule organogenesis in wild-type Lotus japonicus ecotype Gifu B-129-S9 plants was performed, to provide the necessary framework for the evaluation of altered phenotypes of L. japonicus symbiotic mutants, Subsequently, chemical ethyl methanesulfonate (EMS) mutagenesis of L. japonicus was carried out. The analysis of approximately 3,000 M(1) plants and their progeny yielded 20 stable L. japonicus symbiotic variants, consisting of at least 14 different symbiosis-associated loci or complementation groups. Moreover, a mutation affecting L. japonicus root development was identified that also conferred a hypernodulation response when a line carrying the corresponding allele (LjEMS102) was inoculated with rhizobia, The phenotype of the LjEMS102 line was characterized by the presence of nodule structures covering almost the entire root length (Nod(++)), and by a concomitant inhibition of both root and stem growth, A mutation in a single nuclear gene was shown to be responsible for both root and symbiotic phenotypes observed in the L, japonicus LjEMS102, line, suggesting that (a) common mechanism(s) regulating root development and nodule formation exists in legumes.

HomeCirculationVol. 27, No. 4Operative Treatment of Aortic Stenosis in the Adult Free AccessResearch ArticlePDF/EPUBAboutView PDFSections ToolsAdd to favoritesDownload citationsTrack citationsPermissions ShareShare onFacebookTwitterLinked InMendeleyReddit Jump toFree AccessResearch ArticlePDF/EPUBOperative Treatment of Aortic Stenosis in the Adult J. GORDON SCANNELL, ROBERT S. SHAW, JOHN F. BURKE, W. GERALD AUSTEN and JUSTUS S. SAURBREY J. GORDON SCANNELLJ. GORDON SCANNELL From the General Surgical Services, Massachusetts General Hospital, Boston, Massachusetts. , ROBERT S. SHAWROBERT S. SHAW From the General Surgical Services, Massachusetts General Hospital, Boston, Massachusetts. , JOHN F. BURKEJOHN F. BURKE From the General Surgical Services, Massachusetts General Hospital, Boston, Massachusetts. , W. GERALD AUSTENW. GERALD AUSTEN From the General Surgical Services, Massachusetts General Hospital, Boston, Massachusetts. and JUSTUS S. SAURBREYJUSTUS S. SAURBREY From the General Surgical Services, Massachusetts General Hospital, Boston, Massachusetts. Originally published1 Apr 1963https://doi.org/10.1161/01.CIR.27.4.772Circulation. 1963;27:772–778 Previous Back to top Next FiguresReferencesRelatedDetailsCited By Ramsay J (1995) The Respiratory, Renal, and Hepatic Systems: Effects of Cardiac Surgery and Cardiopulmonary Bypass Cardiopulmonary Bypass, 10.1007/978-1-4612-2484-6_7, (147-168), . Allen B, Buckberg G, Rosenkranz E, Plested W, Skow J, Mazzei E and Scanlan R (1992) Topical cardiac hypothermia in patients with coronary disease, The Journal of Thoracic and Cardiovascular Surgery, 10.1016/S0022-5223(19)34727-0, 104:3, (626-631), Online publication date: 1-Sep-1992. Robicsek F, Duncan G, Hawes A, Rice H, Harrill S and Robicsek S (1990) Biological thresholds of cold-induced phrenic nerve injury, The Journal of Thoracic and Cardiovascular Surgery, 10.1016/S0022-5223(19)35647-8, 99:1, (167-170), Online publication date: 1-Jan-1990. Shapira N, Lemole G, Fernandez J, Daily P, Dembitsky W, O'Yek V, Haghighi P, Stewart J, Marsh D and Bloor C (1990) Aortic valve repair for aortic stenosis in adults, The Annals of Thoracic Surgery, 10.1016/0003-4975(90)90100-K, 50:1, (110-120), Online publication date: 1-Jul-1990. Robicsek F, Duncan G, Rice H and Robicsek S (1989) Experiments with a bowl of saline: The hidden risk of hypothermic-osmotic damage during topical cardiac cooling, The Journal of Thoracic and Cardiovascular Surgery, 10.1016/S0022-5223(19)34587-8, 97:3, (461-466), Online publication date: 1-Mar-1989. Selzer A (1987) Changing Aspects of the Natural History of Valvular Aortic Stenosis, New England Journal of Medicine, 10.1056/NEJM198707093170206, 317:2, (91-98), Online publication date: 9-Jul-1987. Chandler K, Rozas C, Kory R and Goldman A (1984) Bilateral diaphragmatic paralysis complicating local cardiac hypothermia during open heart surgery, The American Journal of Medicine, 10.1016/0002-9343(84)90698-3, 77:2, (243-249), Online publication date: 1-Aug-1984. Finegan R, Gianelly R and Harrison D (1969) Aortic Stenosis in the Elderly, New England Journal of Medicine, 10.1056/NEJM196912042812302, 281:23, (1261-1264), Online publication date: 4-Dec-1969. Fraser R and Waddell J (1967) Systemic embolization after aortic valve replacement, The Journal of Thoracic and Cardiovascular Surgery, 10.1016/S0022-5223(19)43117-6, 54:1, (81-84), Online publication date: 1-Jul-1967. Hurley P, Lowe J and Barratt-Boyes B (1967) Debridement-valvotomy for aortic stenosis in adults: A follow-up of 76 patients, Thorax, 10.1136/thx.22.4.314, 22:4, (314-319), Online publication date: 1-Jul-1967. Austen W, DeSanctis R, Sanders C and Scannell J (1965) THE SURGICAL TREATMENT OF ACQUIRED TRIVALVULAR DISEASE, The Journal of Thoracic and Cardiovascular Surgery, 10.1016/S0022-5223(19)33260-X, 49:4, (640-648), Online publication date: 1-Apr-1965. Ueland K (1965) Cardiac surgery and pregnancy, American Journal of Obstetrics and Gynecology, 10.1016/0002-9378(65)90115-8, 92:1, (148-162), Online publication date: 1-May-1965. Scannell J and Austen W (2016) Surgical Challenge of Aortic Valve Disease, Postgraduate Medicine, 10.1080/00325481.1965.11695515, 37:5, (572-575), Online publication date: 1-May-1965. Effler D, Favaloro R and Groves L (1965) Heart Valve Replacement: Clinical Experience, The Annals of Thoracic Surgery, 10.1016/S0003-4975(10)66717-3, 1:1, (4-24), Online publication date: 1-Jan-1965. Brandenburg R (1965) Medical problems of aortic valve replacement, Progress in Cardiovascular Diseases, 10.1016/S0033-0620(65)80032-9, 7:6, (531-543), Online publication date: 1-May-1965. Scannell J and Austen W (1964) Operative Treatment of Aortic Stenosis in the Elderly Patient, New England Journal of Medicine, 10.1056/NEJM196401092700208, 270:2, (96-97), Online publication date: 9-Jan-1964. April 1, 1963Vol 27, Issue 4 Advertisement Article InformationMetrics © 1963 American Heart Association, Inc.https://doi.org/10.1161/01.CIR.27.4.772 Originally publishedApril 1, 1963 PDF download Advertisement

A study was undertaken to establish whether the use of stored ACD blood, up to four days old and subsequently heparinized and recalcified, in the pump‐oxygenator for open‐heart surgery would have any detrimental effect upon postoperative coagulation and hemostasis. A comparison was made with cases in which fresh heparinized blood was used.Postoperative abnormalities were encountered in all patients. There was no significant difference between the two groups. No evidence was found of any disadvantage in the use of ACD blood.

MUCH has been written about occlusive disease involving the great vessels of the aortic arch since the first reports on this subject by Savory1 in 1856 and Broadbent2 in 1875. This clinical entity, which has been variously referred to under such names as "aortic-arch syndrome,"3 , 4 "pulseless disease,"5 "Martorell's syndrome"6 and "Takayasu's disease,"7 probably has several etiologies — the inflammatory arteritis of syphilis,3 , 8 atherosclerosis9 10 11 12 and the poorly understood nonspecific inflammatory lesion,3 4 5 , 10 , 13 14 15 the ophthalmologic complications of which were described by Takayasu7 in 1908. It is important not to consider these various types of occlusive disease involving the major branches of the aortic . . .