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Sample records for john von neumann

  1. John von Neumann Birthday Centennial

    SciTech Connect

    Grcar, Joseph F.

    2004-11-12

    In celebration of John von Neumann's 100th birthday, a series of four lectures were presented on the evening of February 10, 2003 during the SIAM Conference on Computational Science and Engineering in San Diego. The venue was appropriate because von Neumann spent much of the later part of his life, in the 1950's, as an unofficial ambassador for computational science. He was then the only senior American scientist who had experience with the new computers (digital, electronic, and programmable) and a vision of their future importance. No doubt he would have relished the chance to attend a meeting such as this. The first speaker, William Aspray, described the ''interesting times'' during which computers were invented. His remarks were based on his history [1] of this period in von Neumann's life. We were honored to have John von Neumann's daughter, Marina von Neumann-Whitman, as our second speaker. Other accounts of von Neumann's life can be found in books by two of his colleagues [2] and [3]. Our third speaker, Peter Lax, provided both mathematical and international perspectives on John von Neumann's career. Finally, Pete Stewart spoke about von Neumann's numerical error analysis [4] in the context of later work; this talk did not lend itself to transcription, but readers may consult the historical notes in [5]. Our thanks to all the speakers for a remarkable evening. We are grateful to the DOE Applied Mathematical Sciences (AMS) program for partially supporting these lectures. Thanks are also due to SIAM and William Kolata, to our emcee, Gene Golub, to Paul Saylor for recording and editing, and to Barbara Lytle for the transcriptions. More about von Neumann's work can be learned from the recent American Mathematical Society proceedings [6].

  2. Papers of John von Neumann on computers and computer theory

    SciTech Connect

    Von Neumann, J.

    1986-01-01

    This volume brings together John von Neumann's long-out-of-print articles on computer architecture, programming, large-scale computing, and automata theory. A number of significant papers in these areas that were not included in the multivolume John von Neumann: Collected Works (1963) have now been reprinted here. These pioneering articles - written between the mid-1940s and the mid-1950s - are of enduring value not only to computer historians but to computer scientists at the vanguard of current research. Most of today's computers are still constructed in accordance with the '' von Neumann architecture,'' and his technique of flow charting remains basic in the domain.

  3. John von Neumann's mathematical "Utopia" in quantum theory

    NASA Astrophysics Data System (ADS)

    Valente, Giovanni

    This paper surveys John von Neumann's work on the mathematical foundations of quantum theories in the light of Hilbert's Sixth Problem concerning the geometrical axiomatization of physics. We argue that in von Neumann's view geometry was so tied to logic that he ultimately developed a logical interpretation of quantum probabilities. That motivated his abandonment of Hilbert space in favor of von Neumann algebras, specifically the type II1 factors, as the proper limit of quantum mechanics in infinite dimensions. Finally, we present the reasons why his axiomatic program remained an "unsolved problem" in mathematical physics. A recent unpublished result by Huzimiro Araki, proving that no algebra with a tracial state defined on it, such as the type II1 factors, can support any (regular) representation of the canonical commutation relations, is also reviewed and its consequences for von Neumann's projects are discussed.

  4. FROM THE HISTORY OF PHYSICS: John von Neumann

    NASA Astrophysics Data System (ADS)

    Monastyrskii, Mikhail I.

    2004-12-01

    This article is dedicated to John von Neumann, one of the most outstanding scholars of the 20th century. His life was short but bright, and his contribution to almost all branches of mathematics, as well as to physics, economics, biology, and astronomy was enormous. He constructed some of the first computers and he was among the key persons in the American atomic project. Development of his ideas will continue to play a vital part in various areas of pure and applied mathematics.

  5. John von Neumann on Mathematical and Axiomatic Physics

    NASA Astrophysics Data System (ADS)

    Rédei, Miklós

    The aim of this paper is to recall and analyse von Neumann's position on mathematical and axiomatic physics. It will be argued that von Neumann demanded much less mathematical rigor in physics than commonly thought and that he followed an opportunistically interpreted soft axiomatic method in physics. The notion of opportunistic soft axiomatization is illustrated by recalling his work on the mathematical foundations of quantum mechanics.

  6. John von Neumann and Klaus Fuchs: an Unlikely Collaboration

    NASA Astrophysics Data System (ADS)

    Bernstein, Jeremy

    2010-03-01

    I discuss the origin of the idea of making a fusion (hydrogen) bomb and the physics involved in it, and then turn to the design proposed for one by the unlikely collaborators John von Neumann and Klaus Fuchs in a patent application they filed at Los Alamos in May 1946, which Fuchs passed on to the Russians in March 1948, and which with substantial modifications was tested on the island of Eberiru on the Eniwetok atoll in the South Pacific on May 8, 1951. This test showed that the fusion of deuterium and tritium nuclei could be ignited, but that the ignition would not propagate because the heat produced was rapidly radiated away. Meanwhile, Stanislaw Ulam and C.J. Everett had shown that Edward Teller’s Classical Super could not work, and at the end of December 1950, Ulam had conceived the idea of super compression, using the energy of a fission bomb to compress the fusion fuel to such a high density that it would be opaque to the radiation produced. Once Teller understood this, he invented a greatly improved, new method of compression using radiation, which then became the heart of the Ulam-Teller bomb design, which was tested, also in the South Pacific, on November 1, 1952. The Russians have freely acknowledged that Fuchs gave them the fission bomb, but they have insisted that no one gave them the fusion bomb, which grew out of design involving a fission bomb surrounded by alternating layers of fusion and fission fuels, and which they tested on November 22, 1955. Part of the irony of this story is that neither the American nor the Russian hydrogen-bomb programs made any use of the brilliant design that von Neumann and Fuchs had conceived as early as 1946, which could have changed the entire course of development of both programs.

  7. Von Neumann was not a Quantum Bayesian.

    PubMed

    Stacey, Blake C

    2016-05-28

    Wikipedia has claimed for over 3 years now that John von Neumann was the 'first quantum Bayesian'. In context, this reads as stating that von Neumann inaugurated QBism, the approach to quantum theory promoted by Fuchs, Mermin and Schack. This essay explores how such a claim is, historically speaking, unsupported. PMID:27091166

  8. Book Review: John von Neumann and the foundations of quantum physics. (Vienna Circle Institute yearbook (2000), 8) Miklos Redei and Michael Stoltzner (Eds.); Kluwer Academic Publishers, Dordrecht, 2001, pp., US 125, ISBN 0792368126

    NASA Astrophysics Data System (ADS)

    Lupher, Tracy

    Some people may be surprised to learn that John von Neumann's work on the foundations of quantum physics went far beyond what is contained within the pages of his Mathematical Foundations of Quantum Mechanics (MFQM) (von Neumann, 1955). However, this narrow focus often ignores von Neumann's later work on quantum logic and what are now called in his honor, von Neumann algebras. This volume honoring von Neumann's contributions to physics is unique in that, while it contains 12 papers that examine various aspects of von Neumann's work, it also contains two of his previously unpublished papers and some of his previously unpublished correspondence.

  9. Quantum theory and geometry: sixty years after von Neumann

    NASA Astrophysics Data System (ADS)

    Varadarajan, V. S.

    1993-10-01

    This paper is a brief review of some of the developments in the mathematical foundations of quantum mechanics that have taken place since the publication in 1932 of John von Neumann's celebrated treatise Mathematische Grundlagen der Quantenmechanik.

  10. The John von Neumann Institute for Computing (NIC): A survey of its supercomputer facilities and its Europe-wide computational science activities

    NASA Astrophysics Data System (ADS)

    Attig, N.

    2006-03-01

    The John von Neumann Institute for Computing (NIC) at the Research Centre Jülich, Germany, is one of the leading supercomputing centres in Europe. Founded as a national centre in the mid-eighties it now provides more and more resources to European scientists. This happens within EU-funded projects (I3HP, DEISA) or Europe-wide scientific collaborations. Beyond these activities NIC started an initiative towards the new EU member states in summer 2004. Outstanding research groups are offered to exploit the supercomputers at NIC to accelerate their investigations on leading-edge technology. The article gives an overview of the organisational structure of NIC, its current supercomputer systems, and its user support. Transnational Access (TA) within I3HP is described as well as access by the initiative for new EU member states. The volume of these offers and the procedure of how to apply for supercomputer resources is introduced in detail.

  11. Long-time behavior of macroscopic quantum systems. Commentary accompanying the English translation of John von Neumann's 1929 article on the quantum ergodic theorem

    NASA Astrophysics Data System (ADS)

    Goldstein, S.; Lebowitz, J. L.; Tumulka, R.; Zanghì, N.

    2010-11-01

    The renewed interest in the foundations of quantum statistical mechanics in recent years has led us to study John von Neumann’s 1929 article on the quantum ergodic theorem. We have found this almost forgotten article, which until now has been available only in German, to be a treasure chest, and to be much misunderstood. In it, von Neumann studied the long-time behavior of macroscopic quantum systems. While one of the two theorems announced in his title, the one he calls the “quantum H-theorem”, is actually a much weaker statement than Boltzmann’s classical H-theorem, the other theorem, which he calls the “quantum ergodic theorem”, is a beautiful and very non-trivial result. It expresses a fact we call “normal typicality” and can be summarized as follows: for a “typical” finite family of commuting macroscopic observables, every initial wave function ψ0 from a micro-canonical energy shell so evolves that for most times t in the long run, the joint probability distribution of these observables obtained from ψt is close to their micro-canonical distribution.

  12. A note on derivations of Murray–von Neumann algebras

    PubMed Central

    Kadison, Richard V.; Liu, Zhe

    2014-01-01

    A Murray–von Neumann algebra is the algebra of operators affiliated with a finite von Neumann algebra. In this article, we first present a brief introduction to the theory of derivations of operator algebras from both the physical and mathematical points of view. We then describe our recent work on derivations of Murray–von Neumann algebras. We show that the “extended derivations” of a Murray–von Neumann algebra, those that map the associated finite von Neumann algebra into itself, are inner. In particular, we prove that the only derivation that maps a Murray–von Neumann algebra associated with a factor of type II1 into that factor is 0. Those results are extensions of Singer’s seminal result answering a question of Kaplansky, as applied to von Neumann algebras: The algebra may be noncommutative and may even contain unbounded elements. PMID:24469831

  13. Approximating incompatible von Neumann measurements simultaneously

    SciTech Connect

    Heinosaari, Teiko; Jivulescu, Maria Anastasia; Reitzner, Daniel; Ziman, Mario

    2010-09-15

    We study the problem of performing orthogonal qubit measurements simultaneously. Since these measurements are incompatible, one has to accept additional imprecision. An optimal joint measurement is the one with the least possible imprecision. All earlier considerations of this problem have concerned only joint measurability of observables, while in this work we also take into account conditional state transformations (i.e., instruments). We characterize the optimal joint instrument for two orthogonal von Neumann instruments as being the Lueders instrument of the optimal joint observable.

  14. Approximate von Neumann entropy for directed graphs.

    PubMed

    Ye, Cheng; Wilson, Richard C; Comin, César H; Costa, Luciano da F; Hancock, Edwin R

    2014-05-01

    In this paper, we develop an entropy measure for assessing the structural complexity of directed graphs. Although there are many existing alternative measures for quantifying the structural properties of undirected graphs, there are relatively few corresponding measures for directed graphs. To fill this gap in the literature, we explore an alternative technique that is applicable to directed graphs. We commence by using Chung's generalization of the Laplacian of a directed graph to extend the computation of von Neumann entropy from undirected to directed graphs. We provide a simplified form of the entropy which can be expressed in terms of simple node in-degree and out-degree statistics. Moreover, we find approximate forms of the von Neumann entropy that apply to both weakly and strongly directed graphs, and that can be used to characterize network structure. We illustrate the usefulness of these simplified entropy forms defined in this paper on both artificial and real-world data sets, including structures from protein databases and high energy physics theory citation networks. PMID:25353841

  15. Group Theoretical Interpretation of von Neumann's Theorem on Composite Systems.

    ERIC Educational Resources Information Center

    Bergia, S.; And Others

    1979-01-01

    Shows that von Neumann's mathematical theorem on composite systems acquires a transparent physical meaning with reference to a suitable physical example; a composite system in a state of definite angular momentum. Gives an outline of the theorem, and the results are restated in Dirac's notation, thus generalizing von Neumann's results which were…

  16. Relative von Neumann entropy for evaluating amino acid conservation.

    PubMed

    Johansson, Fredrik; Toh, Hiroyuki

    2010-10-01

    The Shannon entropy is a common way of measuring conservation of sites in multiple sequence alignments, and has also been extended with the relative Shannon entropy to account for background frequencies. The von Neumann entropy is another extension of the Shannon entropy, adapted from quantum mechanics in order to account for amino acid similarities. However, there is yet no relative von Neumann entropy defined for sequence analysis. We introduce a new definition of the von Neumann entropy for use in sequence analysis, which we found to perform better than the previous definition. We also introduce the relative von Neumann entropy and a way of parametrizing this in order to obtain the Shannon entropy, the relative Shannon entropy and the von Neumann entropy at special parameter values. We performed an exhaustive search of this parameter space and found better predictions of catalytic sites compared to any of the previously used entropies. PMID:20981889

  17. Von Neumann's growth model: Statistical mechanics and biological applications

    NASA Astrophysics Data System (ADS)

    De Martino, A.; Marinari, E.; Romualdi, A.

    2012-09-01

    We review recent work on the statistical mechanics of Von Neumann's growth model and discuss its application to cellular metabolic networks. In this context, we present a detailed analysis of the physiological scenario underlying optimality à la Von Neumann in the metabolism of the bacterium E. coli, showing that optimal solutions are characterized by a considerable microscopic flexibility accompanied by a robust emergent picture for the key physiological functions. This suggests that the ideas behind optimal economic growth in Von Neumann's model can be helpful in uncovering functional organization principles of cell energetics.

  18. Valence bond and von Neumann entanglement entropy in Heisenberg ladders.

    PubMed

    Kallin, Ann B; González, Iván; Hastings, Matthew B; Melko, Roger G

    2009-09-11

    We present a direct comparison of the recently proposed valence bond entanglement entropy and the von Neumann entanglement entropy on spin-1/2 Heisenberg systems using quantum Monte Carlo and density-matrix renormalization group simulations. For one-dimensional chains we show that the valence bond entropy can be either less or greater than the von Neumann entropy; hence, it cannot provide a bound on the latter. On ladder geometries, simulations with up to seven legs are sufficient to indicate that the von Neumann entropy in two dimensions obeys an area law, even though the valence bond entanglement entropy has a multiplicative logarithmic correction. PMID:19792398

  19. A proof of von Neumann's postulate in Quantum Mechanics

    SciTech Connect

    Conte, Elio

    2010-05-04

    A Clifford algebraic analysis is explained. It gives proof of von Neumann's postulate on quantum measurement. It is of basic significance to explain the problem of quantum wave function reduction in quantum mechanics.

  20. Logo and Von Neumann Ideas [and] Towards a Humanistic Use of Computers in Education = Hacia una insercion humanista de las computadoras en la educacion.

    ERIC Educational Resources Information Center

    Reggini, Horacio C.

    The first article, "LOGO and von Neumann Ideas," deals with the creation of new procedures based on procedures defined and stored in memory as LOGO lists of lists. This representation, which enables LOGO procedures to construct, modify, and run other LOGO procedures, is compared with basic computer concepts first formulated by John von Neumann.…

  1. Von Neumann's `No Hidden Variables' Proof: A Re-Appraisal

    NASA Astrophysics Data System (ADS)

    Bub, Jeffrey

    2010-10-01

    Since the analysis by John Bell in 1965, the consensus in the literature is that von Neumann’s ‘no hidden variables’ proof fails to exclude any significant class of hidden variables. Bell raised the question whether it could be shown that any hidden variable theory would have to be nonlocal, and in this sense ‘like Bohm’s theory.’ His seminal result provides a positive answer to the question. I argue that Bell’s analysis misconstrues von Neumann’s argument. What von Neumann proved was the impossibility of recovering the quantum probabilities from a hidden variable theory of dispersion free (deterministic) states in which the quantum observables are represented as the ‘beables’ of the theory, to use Bell’s term. That is, the quantum probabilities could not reflect the distribution of pre-measurement values of beables, but would have to be derived in some other way, e.g., as in Bohm’s theory, where the probabilities are an artefact of a dynamical process that is not in fact a measurement of any beable of the system.

  2. The von Neumann Triple Point Paradox

    NASA Astrophysics Data System (ADS)

    Sanders, Richard; Tesdall, Allen M.

    We describe the problem of weak shock reflection off a wedge and discuss the triple point paradox that arises. When the shock is sufficiently weak and the wedge is thin, Mach reflection appears to be observed but is impossible according to what von Neumann originally showed in 1943. We summarize some recent numerical results for weak shock reflection problems for the unsteady transonic small disturbance equations, the nonlinear wave system, and the Euler equations. Rather than finding a standard but mathematically inadmissible Mach reflection with a shock triple point, the solutions contain a complex structure: there is a sequence of triple points and supersonic patches in a tiny region behind the leading triple point, with an expansion fan originating at each triple point. The sequence of patches may be infinite, and we refer to this structure as Guderley Mach reflection. The presence of the expansion fans at the triple points resolves the paradox. We describe some recent experimental evidence which is consistent with these numerical findings.

  3. Locally Compact Quantum Groups. A von Neumann Algebra Approach

    NASA Astrophysics Data System (ADS)

    Van Daele, Alfons

    2014-08-01

    In this paper, we give an alternative approach to the theory of locally compact quantum groups, as developed by Kustermans and Vaes. We start with a von Neumann algebra and a comultiplication on this von Neumann algebra. We assume that there exist faithful left and right Haar weights. Then we develop the theory within this von Neumann algebra setting. In [Math. Scand. 92 (2003), 68-92] locally compact quantum groups are also studied in the von Neumann algebraic context. This approach is independent of the original C^*-algebraic approach in the sense that the earlier results are not used. However, this paper is not really independent because for many proofs, the reader is referred to the original paper where the C^*-version is developed. In this paper, we give a completely self-contained approach. Moreover, at various points, we do things differently. We have a different treatment of the antipode. It is similar to the original treatment in [Ann. Sci. & #201;cole Norm. Sup. (4) 33 (2000), 837-934]. But together with the fact that we work in the von Neumann algebra framework, it allows us to use an idea from [Rev. Roumaine Math. Pures Appl. 21 (1976), 1411-1449] to obtain the uniqueness of the Haar weights in an early stage. We take advantage of this fact when deriving the other main results in the theory. We also give a slightly different approach to duality. Finally, we collect, in a systematic way, several important formulas. In an appendix, we indicate very briefly how the C^*-approach and the von Neumann algebra approach eventually yield the same objects. The passage from the von Neumann algebra setting to the C^*-algebra setting is more or less standard. For the other direction, we use a new method. It is based on the observation that the Haar weights on the C^*-algebra extend to weights on the double dual with central support and that all these supports are the same. Of course, we get the von Neumann algebra by cutting down the double dual with this unique

  4. (Never) Mind your p's and q's: Von Neumann versus Jordan on the foundations of quantum theory

    NASA Astrophysics Data System (ADS)

    Duncan, A.; Janssen, M.

    2013-03-01

    In 1927, in two papers entitled "On a new foundation [Neue Begründung] of quantum mechanics," Pascual Jordan presented his version of what came to be known as the Dirac-Jordan statistical transformation theory. Jordan and Paul Dirac arrived at essentially the same theory independently of one another at around the same time. Later in 1927, partly in response to Jordan and Dirac and avoiding the mathematical difficulties facing their approach, John von Neumann developed the modern Hilbert space formalism of quantum mechanics. We focus on Jordan and von Neumann. Central to the formalisms of both are expressions for conditional probabilities of finding some value for one quantity given the value of another. Beyond that Jordan and von Neumann had very different views about the appropriate formulation of problems in quantum mechanics. For Jordan, unable to let go of the analogy to classical mechanics, the solution of such problems required the identification of sets of canonically conjugate variables, i.e., p's and q's. For von Neumann, not constrained by the analogy to classical mechanics, it required only the identification of a maximal set of commuting operators with simultaneous eigenstates. He had no need for p's and q's. Jordan and von Neumann also stated the characteristic new rules for probabilities in quantum mechanics somewhat differently. Jordan and Dirac were the first to state those rules in full generality. Von Neumann rephrased them and, in a paper published a few months later, sought to derive them from more basic considerations. In this paper we reconstruct the central arguments of these 1927 papers by Jordan and von Neumann and of a paper on Jordan's approach by Hilbert, von Neumann, and Nordheim. We highlight those elements in these papers that bring out the gradual loosening of the ties between the new quantum formalism and classical mechanics. This paper was written as part of a joint project in the history of quantum physics of the Max Planck

  5. Gamma Stability in Free Product von Neumann Algebras

    NASA Astrophysics Data System (ADS)

    Houdayer, Cyril

    2015-06-01

    Let be a free product of arbitrary von Neumann algebras endowed with faithful normal states. Assume that the centralizer is diffuse. We first show that any intermediate subalgebra which has nontrivial central sequences in M is necessarily equal to M 1. Then we obtain a general structural result for all the intermediate subalgebras with expectation. We deduce that any diffuse amenable von Neumann algebra can be concretely realized as a maximal amenable subalgebra with expectation inside a full nonamenable type III1 factor. This provides the first class of concrete maximal amenable subalgebras in the framework of type III factors. We finally strengthen all these results in the case of tracial free product von Neumann algebras.

  6. The smooth entropy formalism for von Neumann algebras

    NASA Astrophysics Data System (ADS)

    Berta, Mario; Furrer, Fabian; Scholz, Volkher B.

    2016-01-01

    We discuss information-theoretic concepts on infinite-dimensional quantum systems. In particular, we lift the smooth entropy formalism as introduced by Renner and collaborators for finite-dimensional systems to von Neumann algebras. For the smooth conditional min- and max-entropy, we recover similar characterizing properties and information-theoretic operational interpretations as in the finite-dimensional case. We generalize the entropic uncertainty relation with quantum side information of Tomamichel and Renner and discuss applications to quantum cryptography. In particular, we prove the possibility to perform privacy amplification and classical data compression with quantum side information modeled by a von Neumann algebra.

  7. The Hochschild cohomology problem for von Neumann algebras

    PubMed Central

    Sinclair, Allan M.; Smith, Roger R.

    1998-01-01

    In 1967, when Kadison and Ringrose began the development of continuous cohomology theory for operator algebras, they conjectured that the cohomology groups Hn(M, M), n ≥ 1, for a von Neumann algebra M, should all be zero. This conjecture, which has important structural implications for von Neumann algebras, has been solved affirmatively in the type I, II∞, and III cases, leaving open only the type II1 case. In this paper, we describe a positive solution when M is type II1 and has a Cartan subalgebra and a separable predual. PMID:9520373

  8. The hochschild cohomology problem for von neumann algebras.

    PubMed

    Sinclair, A M; Smith, R R

    1998-03-31

    In 1967, when Kadison and Ringrose began the development of continuous cohomology theory for operator algebras, they conjectured that the cohomology groups Hn(M, M), n >/= 1, for a von Neumann algebra M, should all be zero. This conjecture, which has important structural implications for von Neumann algebras, has been solved affirmatively in the type I, IIinfinity, and III cases, leaving open only the type II1 case. In this paper, we describe a positive solution when M is type II1 and has a Cartan subalgebra and a separable predual. PMID:9520373

  9. An Accurate von Neumann's Law for Three-Dimensional Foams

    SciTech Connect

    Hilgenfeldt, Sascha; Kraynik, Andrew M.; Koehler, Stephan A.; Stone, Howard A.

    2001-03-19

    The diffusive coarsening of 2D soap froths is governed by von Neumann's law. A statistical version of this law for dry 3D foams has long been conjectured. A new derivation, based on a theorem by Minkowski, yields an explicit analytical von Neumann's law in 3D which is in very good agreement with detailed simulations and experiments. The average growth rate of a bubble with F faces is shown to be proportional to F{sup 1/2} for large F , in contrast to the conjectured linear dependence. Accounting for foam disorder in the model further improves the agreement with data.

  10. von Neumann entropy of N interacting pencils of radiation

    SciTech Connect

    Barakat, R. ); Brosseau, C. )

    1993-03-01

    The von Neumann entropy of N interacting pencils of radiation is analyzed by using their spectral density matrix. When the cross-spectral density is the same for all pairs of pencils, the entropy is evaluated in closed form as a function of Barakat's N-fold polarization measures. Some technical and historical remarks are made concerning the Planck-von Laue entropy of such pencils. 16 refs., 3 figs.

  11. Foam coarsening: von Neumann's law in three dimensions is non-linear

    NASA Astrophysics Data System (ADS)

    Hilgenfeldt, Sascha; Kraynik, Andrew M.; Koehler, Stephan A.; Stone, Howard A.

    2001-11-01

    Fifty years ago, John von Neumann proved that the coarsening rate of individual bubbles in a 2-D dry foam is a linear function of the number of edges of the polygonal bubble. By analogy, it has been conjectured that the average growth rates of 3-D polyhedral bubbles scale linearly with the number F of faces. Using a theorem by Minkowski, we derive a parameter-free analytical expression for the average growth rates and show that the 3-D von Neumann law is non-linear, asymptoting to a square-root power in F. Detailed simulations are in exceptionally good agreement with the analytical formula. This result is important for the understanding of the geometrical structure and aging dynamics of many random cellular materials beyond foams, such as metal grains, spin glasses, or living cells.

  12. Replacing energy by von Neumann entropy in quantum phase transitions

    SciTech Connect

    Kopp, Angela; Jia Xun; Chakravarty, Sudip . E-mail: sudip@physics.ucla.edu

    2007-06-15

    We propose that quantum phase transitions are generally accompanied by non-analyticities of the von Neumann (entanglement) entropy. In particular, the entropy is non-analytic at the Anderson transition, where it exhibits unusual fractal scaling. We also examine two dissipative quantum systems of considerable interest to the study of decoherence and find that non-analyticities occur if and only if the system undergoes a quantum phase transition.

  13. Interpolatability distinguishes LOCC from separable von Neumann measurements

    SciTech Connect

    Childs, Andrew M.; Leung, Debbie; Mančinska, Laura; Ozols, Maris

    2013-11-15

    Local operations with classical communication (LOCC) and separable operations are two classes of quantum operations that play key roles in the study of quantum entanglement. Separable operations are strictly more powerful than LOCC, but no simple explanation of this phenomenon is known. We show that, in the case of von Neumann measurements, the ability to interpolate measurements is an operational principle that sets apart LOCC and separable operations.

  14. Reevaluation of McCulloch-Pitts-von Neumann's clock.

    PubMed

    Ohta, Hiroyuki

    2015-01-01

    In neuroscience research, a firing pattern expression, called a firing snapshot, defined by firing counts of multiple neurons in discrete time-bin is frequently used. However, the firing pattern expression over multiple neurons requires synchronization commonly known as a "central clock" in computation circuits to externally control or observe multi-neuron firing. Since it is not appropriate to hypothesize the central clock in the brain, we have to reconsider the synchronization assumption. We found the historical origins of central clock synchronization in the works of McCulloch, Pitts and von Neumann and propose an alternative perspective to study neural processing without the central clock. In the "First draft of a report on the EDVAC" known as the first proposal of store-program type computer, von Neumann incorporated McCulloch and Pitts' arbitrary assumption of constant synaptic delay into the logical circuit modeling. He introduced a constant pulse delay stabilized by a central clock to synchronize multiple pulse lines. This constant delay carried over to automaton theory by von Neumann and then theoretical neuroscience as an integral part of distributed representation and firing pattern analysis. Instead, we propose a rethinking of neuronal processing by focusing on a variable synaptic delay. We review neuron-type dependent differences and point out that the maximum inter-stimulus interval which can affect the last stimulus response is longer than the minimum inter-spike interval, indicating the possibility of asynchronous input summation without a firing rate level clock. This fundamental baseline contributes to the investigation of time consuming processes: e.g., the compression of appositional synaptic inputs with duration into a single firing. PMID:25458264

  15. Quantum Dynamics in Phase Space using Projected von Neumann Bases.

    PubMed

    Machnes, Shai; Assémat, Elie; Larsson, Henrik R; Tannor, David J

    2016-05-19

    We describe the mathematical underpinnings of the biorthogonal von Neumann method for quantum mechanical simulations (PvB). In particular, we present a detailed discussion of the important issue of nonorthogonal projection onto subspaces of biorthogonal bases, and how this differs from orthogonal projection. We present various representations of the Schrödinger equation in the reduced basis and discuss their relative merits. We conclude with illustrative examples and a discussion of the outlook and challenges ahead for the PvB representation. PMID:26977715

  16. The von Neumann model of measurement in quantum mechanics

    SciTech Connect

    Mello, Pier A.

    2014-01-08

    We describe how to obtain information on a quantum-mechanical system by coupling it to a probe and detecting some property of the latter, using a model introduced by von Neumann, which describes the interaction of the system proper with the probe in a dynamical way. We first discuss single measurements, where the system proper is coupled to one probe with arbitrary coupling strength. The goal is to obtain information on the system detecting the probe position. We find the reduced density operator of the system, and show how Lüders rule emerges as the limiting case of strong coupling. The von Neumann model is then generalized to two probes that interact successively with the system proper. Now we find information on the system by detecting the position-position and momentum-position correlations of the two probes. The so-called 'Wigner's formula' emerges in the strong-coupling limit, while 'Kirkwood's quasi-probability distribution' is found as the weak-coupling limit of the above formalism. We show that successive measurements can be used to develop a state-reconstruction scheme. Finally, we find a generalized transform of the state and the observables based on the notion of successive measurements.

  17. von Neumann entropy associated with the haldane exclusion statistics

    SciTech Connect

    Rajagopal, A.K. )

    1995-02-13

    We obtain the von Neumann entropy per state of the Haldane exclusion statistics with parameter [ital g] in terms of the mean occupation number [bar n][l brace][ital w]ln[ital w][minus](1+[ital w])ln(1+[ital w])[r brace], where [ital w]=(1[minus][bar n]). This reduces correctly to the well known expressions in the limiting cases of Bose ([ital g]=0) and Fermi ([ital g]=1) statistics. We have derived the second and third order fluctuations in the occupation numbers for arbitrary [ital g]. An elegant general duality relationship between the [ital w] factor associated with the particle and that associated with the hole at the reciprocal [ital g] is deduced along with the attendant relationship between the two respective entropies.

  18. A non-linear von Neumann law for three-dimensional foam coarsening

    NASA Astrophysics Data System (ADS)

    Hilgenfeldt, Sascha; Kraynik, Andrew M.; Koehler, Stephan A.; Stone, Howard A.

    2001-03-01

    About 50 years ago, John von Neumann proved that the coarsening rate of individual bubbles in a 2-D dry foam is a linear function of the number of edges of the polygonal bubble. Soon afterwards it was conjectured that a statistical analog holds in three dimensions: polyhedral bubbles with a given number F of faces have an average growth rate that scales linearly in F. Using a theorem by Minkowski, we derive a parameter-free analytical expression for the average growth rates and show that it is non-linear, asymptoting to a square-root power in F. Experimental data and detailed foam simulations are in exceptionally good agreement with the analytical results. A refined model incorporates foam disorder to further improve the predictive power of the theory.

  19. von Neumann's Law: Theoretical and Microgravity Experimental Comparison for Coarsening Diffusion in Bubble Lattices

    NASA Technical Reports Server (NTRS)

    Noever, David A.

    2000-01-01

    The effects of gravity in influencing the theoretical limit for bubble lattice coarsening and aging behavior, otherwise called von Neumann's law, is examined theoretically and experimentally. Preliminary microgravity results will be discussed.

  20. Markov property and strong additivity of von Neumann entropy for graded quantum systems

    SciTech Connect

    Moriya, Hajime

    2006-03-15

    The quantum Markov property is equivalent to the strong additivity of von Neumann entropy for graded quantum systems. The additivity of von Neumann entropy for bipartite graded systems implies the statistical independence of states. However, the structure of Markov states for graded systems is different from that for tensor-product systems which have trivial grading. For three-composed graded systems we have U(1)-gauge invariant Markov states whose restriction to the marginal pair of subsystems is nonseparable.

  1. Radiometric Trouble with Rough Surfaces? ... The von Neumann Series can Help!

    NASA Astrophysics Data System (ADS)

    Davis, A. B.

    2004-05-01

    Operational retrieval methods used in surface remote sensing will generally assume that the interrogated terrain is uniform as well as flat (if not outright horizontal) at least at sub-pixel scales. Both assumptions are highly questionable. There are spectral techniques (linear un-mixing, end-members, etc.) designed to address the non-uniformity issue and adjacency effects (nonlinear mixing) near large gradients in surface albedo can be unraveled with techniques using the Green function of the aerosol atmosphere. But strong deviations from local flatness define a challenging problem in three-dimensional radiative transfer; this is especially true when the terrain has a very rough fractal shape with height variability over a wide range of scales. The source of the problem is the multiple reflections between surface elements in view of each other and is mathematically akin to the problem of multiple scattering in heterogeneous turbid media like clouds. The fundamental solution to the multiple scattering/reflection problem in transport theory is called ``successive orders-of-scattering/reflection'' by physicists and a ``von Neumann expansion'' by mathematicians. I have applied this method to the analysis of two remote sensing problems that appear to be vastly different: (1) angular dependence of effective emissivity in thermal remote sensing, and (2) biases in fine laser altimetry (such as attempted by NASA's present GLAS mission which focuses on polar ice caps). The thermal problem can be reduced to a question of mean aspect ratio in the macro-roughness of the surface. The altimetry problem calls furthermore for a roughness scale. In both cases, corrections can be made to obtain the surface property of interest: actual emissivity, and actual altitude. In both cases, Monte Carlo simulation ---another seminal contribution of John von Neumann, with others--- was the key to first inspiring and then validating the proposed analytical models with one or two free parameters

  2. Shannon and von Neumann entropy of random networks with heterogeneous expected degree.

    PubMed

    Anand, Kartik; Bianconi, Ginestra; Severini, Simone

    2011-03-01

    Entropic measures of complexity are able to quantify the information encoded in complex network structures. Several entropic measures have been proposed in this respect. Here we study the relation between the Shannon entropy and the von Neumann entropy of networks with given expected degree sequence. We find in different examples of network topologies that when the degree distribution contains some heterogeneity, an intriguing correlation emerges between the two entropic quantities. This results seems to suggest that heterogeneity in the expected degree distribution is implying an equivalence between a quantum and a classical description of networks, which respectively corresponds to the von Neumann and the Shannon entropy. PMID:21517560

  3. Physical Realization of von Neumann Lattices in Rotating Bose Gases with Dipole Interatomic Interactions

    PubMed Central

    Cheng, Szu-Cheng; Jheng, Shih-Da

    2016-01-01

    This paper reports a novel type of vortex lattice, referred to as a bubble crystal, which was discovered in rapidly rotating Bose gases with long-range interactions. Bubble crystals differ from vortex lattices which possess a single quantum flux per unit cell, while atoms in bubble crystals are clustered periodically and surrounded by vortices. No existing model is able to describe the vortex structure of bubble crystals; however, we identified a mathematical lattice, which is a subset of coherent states and exists periodically in the physical space. This lattice is called a von Neumann lattice, and when it possesses a single vortex per unit cell, it presents the same geometrical structure as an Abrikosov lattice. In this report, we extend the von Neumann lattice to one with an integral number of flux quanta per unit cell and demonstrate that von Neumann lattices well reproduce the translational properties of bubble crystals. Numerical simulations confirm that, as a generalized vortex, a von Neumann lattice can be physically realized using vortex lattices in rapidly rotating Bose gases with dipole interatomic interactions. PMID:27545446

  4. Physical Realization of von Neumann Lattices in Rotating Bose Gases with Dipole Interatomic Interactions.

    PubMed

    Cheng, Szu-Cheng; Jheng, Shih-Da

    2016-01-01

    This paper reports a novel type of vortex lattice, referred to as a bubble crystal, which was discovered in rapidly rotating Bose gases with long-range interactions. Bubble crystals differ from vortex lattices which possess a single quantum flux per unit cell, while atoms in bubble crystals are clustered periodically and surrounded by vortices. No existing model is able to describe the vortex structure of bubble crystals; however, we identified a mathematical lattice, which is a subset of coherent states and exists periodically in the physical space. This lattice is called a von Neumann lattice, and when it possesses a single vortex per unit cell, it presents the same geometrical structure as an Abrikosov lattice. In this report, we extend the von Neumann lattice to one with an integral number of flux quanta per unit cell and demonstrate that von Neumann lattices well reproduce the translational properties of bubble crystals. Numerical simulations confirm that, as a generalized vortex, a von Neumann lattice can be physically realized using vortex lattices in rapidly rotating Bose gases with dipole interatomic interactions. PMID:27545446

  5. Commutation of Projections and Characterization of Traces on von Neumann Algebras. III

    NASA Astrophysics Data System (ADS)

    Bikchentaev, A. M.

    2015-12-01

    We obtain new necessary and sufficient commutation conditions for nonnegative operators and projections in terms of operator inequalities. It is shown that in the general case in this inequalities the projections cannot be replaced by arbitrary nonnegative operators with preservation of operators commutativity. We also present new necessary and sufficient commutation conditions for projections in terms of operator inequalities. These inequalities are applied for trace characterization on von Neumann algebras in the class of all positive normal functionals. We also consider the following problems: I. Characterization of traces among arbitrary weights on von Neumann algebras. II. Characterization of tracial functionals among all positive linear functionals on C ∗-algebras. III. Characterization of commutativity for C ∗-algebras.

  6. Examination of the von Neumann paradox for a weak shock wave

    NASA Astrophysics Data System (ADS)

    Kobayashi, Susumu; Adachi, Takashi; Suzuki, Tateyuki

    1995-12-01

    Oblique reflections of a weak shock wave have been investigated both theoretically and experimentally. A modified three-shock theory is introduced to explain the well-known von Neumann paradox for weak Mach reflection. As a physical reality, the triple point is not a mathematical point and the slipstream has a finite thickness. Consequently, the effect of the slipstream divergence behind the triple point and the minute pressure differences on both sides of the slipstream are taken into account, and both these effects are examined numerically. The angle of divergence is given parametrically in order to calculate some characteristics around the triple point, e.g., the angle of reflection. Numerical results are compared with measurements, and characteristics of solutions are examined. It is found that for weak Mach reflection the modified three-shock theory gives physically realistic solutions, even when von Neumann's three-shock theory has no solution. It is also found that the divergence effect of the slipstream is predominant over the pressure difference. All the experimental data are found to exist in the domain bounded by von Neumann's classical theories and the modified three-shock theory proposed here. The experimental evidence of slipstream divergence is presented.

  7. Distinguishability of countable quantum states and von Neumann lattice

    NASA Astrophysics Data System (ADS)

    Kawakubo, Ryûitirô; Koike, Tatsuhiko

    2016-07-01

    The condition for distinguishability of a countably infinite number of pure states by a single measurement is given. Distinguishability is to be understood as the possibility of an unambiguous measurement. For a finite number of states, it is known that the necessary and sufficient condition of distinguishability is that the states are linearly independent. For an infinite number of states, several natural classes of distinguishability can be defined. We give a necessary and sufficient condition for a system of pure states to be distinguishable. It turns out that each level of distinguishability naturally corresponds to one of the generalizations of linear independence to families of infinite vectors. As an important example, we apply the general theory to von Neumann’s lattice, a subsystem of coherent states which corresponds to a lattice in the classical phase space. We prove that the condition for distinguishability is that the area of the fundamental region of the lattice is greater than the Planck constant, and also find subtle behavior on the threshold. These facts reveal the measurement theoretical meaning of the Planck constant and give a justification for the interpretation that it is the smallest unit of area in the phase space. The cases of uncountably many states and of mixed states are also discussed.

  8. Constants in estimates for the rates of convergence in von Neumann's and Birkhoff's ergodic theorems

    SciTech Connect

    Kachurovskii, Alexander G; Sedalishchev, Vladimir V

    2011-08-31

    The paper investigates estimates which relate two equivalent phenomena: the power-type rate of convergence in von Neumann's ergodic theorem and the power-type singularity at zero (with the same exponent) exhibited by the spectral measure of the function being averaged with respect to the corresponding dynamical system. The same rate of convergence is also estimated in terms of the rate of decrease of the correlation coefficients. Also, constants are found in analogous estimates for the power-type convergence in Birkhoff's ergodic theorem. All the results have exact analogues for wide-sense stationary stochastic processes. Bibliography: 15 titles.

  9. Gravity Effects in Diffusive Coarsening of Bubble Lattices: von Neumann's Law

    NASA Technical Reports Server (NTRS)

    Noever, David A.

    2000-01-01

    von Neumann modelled the evolution of two-dimensional soap froths as a purely diffusive phenomenon; the area growth of a given cell was found to depend only on the geometry of the bubble lattice. In the model, hexagons are stable, pentagons shrink and heptagons grow. The simplest equivalent to the area growth law is / approximately t(sub beta). The result depends on assuming (1) an incompressible gas; (2) bubble walls which meet at 120 deg and (3) constant wall thickness and curvature. Each assumption is borne out in experiments except the last one: bubble wall thickness between connecting cells varies in unit gravity because of gravity drainage. The bottom part of the soap membrane is thickened, the top part is thinned, such that gas diffusion across the membrane shows a complex dependence on gravity. As a result, experimental tests of von Neumann's law have been influenced by effects of gravity; fluid behavior along cell borders can give non-uniform wall thicknesses and thus alter the effective area and gas diffusion rates between adjacent bubbles. For area plotted as a function of time, Glazier (J.A. Glazier, S.P. Gross, and I. Stavans, Phys. Rev. A. 36, 306 (1987); J. Stavans, J.A, Glazier, Phys. Rev. Lett. 62, 1318 (1989).) suggest that in some cases their failure to observe von Neumann's predicted growth exponent ((sup beta)theor(sup =1; beta)exp(sup =0.70 + 0.10)) may have been the result of such "fluid drainage onto the lower glass plate". Additional experiments which varied plate spacing gave different beta exponents in a fashion consistent with this suggestion. During preliminary long duration experiments (approximately 100 h) aboard Spacelab-J, a low-gravity test of froth coarsening has examined (1) power law scaling of von Neumann's law (beta values) in the appropriate diffusive limits; (2) new bubble lattice dynamics such as greater fluid wetting behavior on froth membranes in low gravity; and (3) explicit relations for the gravity

  10. Real-space finite difference scheme for the von Neumann equation with the Dirac Hamiltonian

    NASA Astrophysics Data System (ADS)

    Schreilechner, Magdalena; Pötz, Walter

    2016-07-01

    A finite difference scheme for the numerical treatment of the von Neumann equation for the (2+1)D Dirac Hamiltonian is presented. It is based on a sequential left-right (ket-bra) application of a staggered space-time scheme for the pure-state Dirac equation and offers a numerical treatment of the general mixed-state dynamics of an isolated quantum system within the von Neumann equation. Thereby this direct scheme inherits all the favorable features of the finite-difference scheme for the pure-state Dirac equation, such as the single-cone energy-momentum dispersion, convergence conditions, and scaling behavior. A conserved functional is identified. Moreover this scheme is shown to conserve both Hermiticity and positivity. Numerical tests comprise a numerical analysis of stability, as well as the simulation of a mixed-state time-evolution of Gaussian wave functions, illustrating Zitterbewegung and transverse current oscillations. Imaginary-potential absorbing boundary conditions and parameters which pertain to topological insulator surface states were used in the numerical simulations.

  11. Eps'88: Combining the best features of von Neumann and dataflow computing

    SciTech Connect

    Grafe, V.G.; Hoch, J.E.; Davidson, G.S.

    1989-01-01

    A new parallel architecture is presented which combines the beneficial features of both dataflow and von Neumann computers. Dynamic exploitation of parallelism is supported by a direct match dataflow scheduling mechanism. The dataflow scheduling mechanism can be applied to individual instructions or to groups of instructions. These groups of instructions are executed in a predetermined order, as in von Neumann machines. This deterministic scheduling allows the reuse of data through common memory locations and the use of local state (registers) to minimize resource requirements and latency. The foundation of this architecture includes single clock, direct matching of operands, dynamically allocated frame-based data storage, and a general repeat function that can dispatch instructions in a predetermined order. The ability to execute fully and partially ordered instruction streams makes the architecture amenable to both imperative and functional languages. The operation of the processor architecture, the associated structured memory system, proposed interconnections, and programming considerations are described. The entire architecture has been captured in a functional simulator, and hardware implementations of several of the vital parts are underway. 7 refs., 17 figs.

  12. von Neumann entropy and localization-delocalization transition of electron states in quantum small-world networks.

    PubMed

    Gong, Longyan; Tong, Peiqing

    2006-11-01

    The von Neumann entropy for an electron in periodic, disorder, and quasiperiodic quantum small-world networks (QSWN's) is studied numerically. For the disorder QSWN's, the derivative of the spectrum-averaged von Neumann entropy is maximal at a certain density of shortcut links p*, which can be as a signature of the localization-delocalization transition of electron states. The transition point p* is agreement with that obtained by the level statistics method. For the quasiperiodic QSWN's, it is found that there are two regions of the potential parameter. The behaviors of electron states in different regions are similar to that of periodic and disorder QSWN's, respectively. PMID:17279964

  13. Generalization of von Neumann analysis for a model of two discrete half-spaces: The acoustic case

    USGS Publications Warehouse

    Haney, M.M.

    2007-01-01

    Evaluating the performance of finite-difference algorithms typically uses a technique known as von Neumann analysis. For a given algorithm, application of the technique yields both a dispersion relation valid for the discrete time-space grid and a mathematical condition for stability. In practice, a major shortcoming of conventional von Neumann analysis is that it can be applied only to an idealized numerical model - that of an infinite, homogeneous whole space. Experience has shown that numerical instabilities often arise in finite-difference simulations of wave propagation at interfaces with strong material contrasts. These interface instabilities occur even though the conventional von Neumann stability criterion may be satisfied at each point of the numerical model. To address this issue, I generalize von Neumann analysis for a model of two half-spaces. I perform the analysis for the case of acoustic wave propagation using a standard staggered-grid finite-difference numerical scheme. By deriving expressions for the discrete reflection and transmission coefficients, I study under what conditions the discrete reflection and transmission coefficients become unbounded. I find that instabilities encountered in numerical modeling near interfaces with strong material contrasts are linked to these cases and develop a modified stability criterion that takes into account the resulting instabilities. I test and verify the stability criterion by executing a finite-difference algorithm under conditions predicted to be stable and unstable. ?? 2007 Society of Exploration Geophysicists.

  14. Exact finite reduced density matrix and von Neumann entropy for the Calogero model

    NASA Astrophysics Data System (ADS)

    Osenda, Omar; Pont, Federico M.; Okopińska, Anna; Serra, Pablo

    2015-12-01

    The information content of continuous quantum variables systems is usually studied using a number of well known approximation methods. The approximations are made to obtain the spectrum, eigenfunctions or the reduced density matrices that are essential to calculate the entropy-like quantities that quantify the information. Even in the sparse cases where the spectrum and eigenfunctions are exactly known, the entanglement spectrum- the spectrum of the reduced density matrices that characterize the problem- must be obtained in an approximate fashion. In this work, we obtain analytically a finite representation of the reduced density matrices of the fundamental state of the N-particle Calogero model for a discrete set of values of the interaction parameter. As a consequence, the exact entanglement spectrum and von Neumann entropy is worked out.

  15. Estimating residue evolutionary conservation by introducing von Neumann entropy and a novel gap-treating approach.

    PubMed

    Zhang, S-W; Zhang, Y-L; Pan, Q; Cheng, Y-M; Chou, K-C

    2008-08-01

    Evolutionary conservation derived from a multiple sequence alignment is a powerful indicator of the functional significance of a residue, and it can help to predict active sites, ligand-binding sites, and protein interaction interfaces. The results of the existing algorithms in identifying the residue's conservation strongly depend on the sequence alignment, making the results highly variable. Here, by introducing the amino acid similarity matrix, we propose a novel gap-treating approach by combining the evolutionary information and von Neumann entropies to compute the residue conservation scores. It is indicated through a series of tested results that the new approach is quite encouraging and promising and may become a useful tool in complementing the existing methods. PMID:17710364

  16. Exceptional points of a Hamiltonian of von Neumann-Wigner type

    NASA Astrophysics Data System (ADS)

    Fernández-García, N.; Hernández, E.; Jáuregui, A.; Mondragón, A.

    2013-05-01

    In this paper, we present and discuss an example of exceptional points in the continuous spectrum of a Hamiltonian of von Neumann-Wigner type associated with a double pole in the normalized Jost eigenfunctions, as functions of the wave number. The two unnormalized Jost energy eigenfunctions are analytic functions of the wave number k for all k complex, but at the exceptional points k = ±q, they coalesce to give rise to Jordan cycles of two generalized bound state quadratically integrable eigenfunctions. The Green function has simple poles at the exceptional points, but the regular scattering eigenfunction vanishes at those points. The scattering matrix is a regular function of the wave number at the exceptional points, that is, S(k) does not have a pole at the exceptional points.

  17. The Photon Shell Game and the Quantum von Neumann Architecture with Superconducting Circuits

    NASA Astrophysics Data System (ADS)

    Mariantoni, Matteo

    2012-02-01

    Superconducting quantum circuits have made significant advances over the past decade, allowing more complex and integrated circuits that perform with good fidelity. We have recently implemented a machine comprising seven quantum channels, with three superconducting resonators, two phase qubits, and two zeroing registers. I will explain the design and operation of this machine, first showing how a single microwave photon | 1 > can be prepared in one resonator and coherently transferred between the three resonators. I will also show how more exotic states such as double photon states | 2 > and superposition states | 0 >+ | 1 > can be shuffled among the resonators as well [1]. I will then demonstrate how this machine can be used as the quantum-mechanical analog of the von Neumann computer architecture, which for a classical computer comprises a central processing unit and a memory holding both instructions and data. The quantum version comprises a quantum central processing unit (quCPU) that exchanges data with a quantum random-access memory (quRAM) integrated on one chip, with instructions stored on a classical computer. I will also present a proof-of-concept demonstration of a code that involves all seven quantum elements: (1), Preparing an entangled state in the quCPU, (2), writing it to the quRAM, (3), preparing a second state in the quCPU, (4), zeroing it, and, (5), reading out the first state stored in the quRAM [2]. Finally, I will demonstrate that the quantum von Neumann machine provides one unit cell of a two-dimensional qubit-resonator array that can be used for surface code quantum computing. This will allow the realization of a scalable, fault-tolerant quantum processor with the most forgiving error rates to date. [4pt] [1] M. Mariantoni et al., Nature Physics 7, 287-293 (2011.)[0pt] [2] M. Mariantoni et al., Science 334, 61-65 (2011).

  18. Analysis of Hydrogen Tunneling in an Enzyme Active Site using von Neumann Measurements

    PubMed Central

    Sumner, Isaiah; Iyengar, Srinivasan S.

    2010-01-01

    We build on our earlier quantum wavepacket study of hydrogen transfer in the biological enzyme, soybean lipoxygenase-1, by using von Neumann quantum measurement theory to gain qualitative insights into the transfer event. We treat the enzyme active site as a measurement device which acts on the tunneling hydrogen nucleus via the potential it exerts at each configuration. A series of changing active site geometries during the tunneling process effects a sequential projection of the initial, reactant state onto the final, product state. We study this process using several different kinds of von Neumann measurements and show how a discrete sequence of such measurements not only progressively increases the projection of the hydrogen nuclear wavepacket onto the product side but also favors proton over deuteron transfer. Several qualitative features of the hydrogen tunneling problem found in wavepacket dynamics studies are also recovered here. These include the shift in the “transition state” towards the reactant as a result of nuclear quantization, greater participation of excited states in the case of deuterium, and presence of critical points along the reaction coordinate that facilitate hydrogen and deuterium transfer and coincide with surface crossings. To further “tailor” the dynamics, we construct a perturbation to the sequence of measurements, that is a perturbation to the dynamical sequence of active site geometry evolution, which leads us to insight on the existence of sensitive regions of the reaction profile where subtle changes to the dynamics of the active site can have an effect on the hydrogen and deuterium transfer process. PMID:22933858

  19. Möbius operators and non-additive quantum probabilities in the Birkhoff-von Neumann lattice

    NASA Astrophysics Data System (ADS)

    Vourdas, A.

    2016-03-01

    The properties of quantum probabilities are linked to the geometry of quantum mechanics, described by the Birkhoff-von Neumann lattice. Quantum probabilities violate the additivity property of Kolmogorov probabilities, and they are interpreted as Dempster-Shafer probabilities. Deviations from the additivity property are quantified with the Möbius (or non-additivity) operators which are defined through Möbius transforms, and which are shown to be intimately related to commutators. The lack of distributivity in the Birkhoff-von Neumann lattice Λd, causes deviations from the law of the total probability (which is central in Kolmogorov's probability theory). Projectors which quantify the lack of distributivity in Λd, and also deviations from the law of the total probability, are introduced. All these operators, are observables and they can be measured experimentally. Constraints for the Möbius operators, which are based on the properties of the Birkhoff-von Neumann lattice (which in the case of finite quantum systems is a modular lattice), are derived. Application of this formalism in the context of coherent states, generalizes coherence to multi-dimensional structures.

  20. Von Neumann entropy and phase distribution of two mode parametric amplifier interacting with a single atom

    SciTech Connect

    Sebawe Abdalla, M. . E-mail: m.sebawe@physics.org; Obada, A.-S.F.; Abdel-Aty, M.

    2005-08-01

    In the present article, we introduce a Hamiltonian model that consists of two modes of the field in a perfect cavity to interact with a single two-level atom. The interaction between the fields has been taken into account and considered to be in the parametric amplifier form. The model in one hand can be regarded as a generalization of the Jaynes-Cummings model (JCM), however, in the other hand it can be considered as a generalization of the parametric amplifier model. Under a certain condition the exact solution to the Schroedinger equation is obtained. Employing this solution and for chosen values of different parameters we discuss numerically the atomic occupation probabilities as well as the degree of entanglement through the entropy of the field. The system shows superstructure phenomenon similar to that appeared from the effect of the Kerr-like medium on the Jaynes-Cummings model. The von Neumann entropy and phase distribution for both two-mode correlated and uncorrelated coherent states cases are also considered.

  1. Optimal transport and von Neumann entropy in a Heisenberg XXZ chain out of equilibrium.

    PubMed

    Salerno, Mario; Popkov, Vladislav

    2013-02-01

    In this paper we investigate the spin currents and the von Neumann entropy (vNE) of a Heisenberg XXZ chain in contact with twisted XY-boundary magnetic reservoirs by means of the Lindblad master equation. Exact solutions for the stationary reduced density matrix are explicitly constructed for chains of small sizes by using a quantum symmetry operation of the system. These solutions are then used to investigate the optimal transport in the chain in terms of the vNE. As a result we show that the maximal spin current always occurs in the proximity of minima of the vNE and for particular choices of parameters (coupling with reservoirs and anisotropy) it can exactly coincide with them. As the coupling is increased, current reversals may occur and in the limit of strong coupling we show that minima of the vNE tend to zero, meaning that the maximal transport is achieved in this case with states that are very close to pure states. PMID:23496461

  2. Classification of motor imagery by means of cortical current density estimation and Von Neumann entropy.

    PubMed

    Kamousi, Baharan; Amini, Ali Nasiri; He, Bin

    2007-06-01

    The goal of the present study is to employ the source imaging methods such as cortical current density estimation for the classification of left- and right-hand motor imagery tasks, which may be used for brain-computer interface (BCI) applications. The scalp recorded EEG was first preprocessed by surface Laplacian filtering, time-frequency filtering, noise normalization and independent component analysis. Then the cortical imaging technique was used to solve the EEG inverse problem. Cortical current density distributions of left and right trials were classified from each other by exploiting the concept of Von Neumann entropy. The proposed method was tested on three human subjects (180 trials each) and a maximum accuracy of 91.5% and an average accuracy of 88% were obtained. The present results confirm the hypothesis that source analysis methods may improve accuracy for classification of motor imagery tasks. The present promising results using source analysis for classification of motor imagery enhances our ability of performing source analysis from single trial EEG data recorded on the scalp, and may have applications to improved BCI systems. PMID:17409476

  3. First principle nonlinear quantum dynamics using a correlation-based von Neumann entropy

    NASA Astrophysics Data System (ADS)

    Westermann, Till; Manthe, Uwe

    2012-05-01

    A new concept to describe the quantum dynamics in complex systems is suggested. It extends established schemes based on the Dirac-Frenkel variation principle, e.g., the multi-configurational time-dependent Hartree (MCTDH) approach. The concept is based on a correlation-based von Neumann entropy (CvN-entropy) definition measuring the complexity of the wavefunction. Equations of motion are derived using a CvN-entropy constraint in the variational principle and result in a generally applicable effective Hamiltonian. It consists of the standard Hamilton operator and an additional nonlinear operator which limits the complexity of the wavefunction. Effectively, this nonlinear operator absorbs complex structures which are emerging in the wavefunction and allows one to introduce non-norm conserving equations of motion. Important aspects of the new concept are outlined studying the wave packet propagation on the diabatic B2 potential energy surfaces of NO2. First, it is demonstrated that during standard wave packet propagation the CvN-entropy increases strongly with time roughly independent of the coordinate systems employed. Second, one finds that employing CvN-entropy constrained MCTDH propagation yields improved wave function accuracy on longer time scales while compromising on the short time accuracy. Third, the loss of the wavefunction's norm is directly related to the overlap with the exact wavefunction. This provides an error estimate available without knowing an exact reference.

  4. First principle nonlinear quantum dynamics using a correlation-based von Neumann entropy.

    PubMed

    Westermann, Till; Manthe, Uwe

    2012-05-28

    A new concept to describe the quantum dynamics in complex systems is suggested. It extends established schemes based on the Dirac-Frenkel variation principle, e.g., the multi-configurational time-dependent Hartree (MCTDH) approach. The concept is based on a correlation-based von Neumann entropy (CvN-entropy) definition measuring the complexity of the wavefunction. Equations of motion are derived using a CvN-entropy constraint in the variational principle and result in a generally applicable effective Hamiltonian. It consists of the standard Hamilton operator and an additional nonlinear operator which limits the complexity of the wavefunction. Effectively, this nonlinear operator absorbs complex structures which are emerging in the wavefunction and allows one to introduce non-norm conserving equations of motion. Important aspects of the new concept are outlined studying the wave packet propagation on the diabatic B(2) potential energy surfaces of NO(2). First, it is demonstrated that during standard wave packet propagation the CvN-entropy increases strongly with time roughly independent of the coordinate systems employed. Second, one finds that employing CvN-entropy constrained MCTDH propagation yields improved wave function accuracy on longer time scales while compromising on the short time accuracy. Third, the loss of the wavefunction's norm is directly related to the overlap with the exact wavefunction. This provides an error estimate available without knowing an exact reference. PMID:22667549

  5. A novel method for the measurement of the von Neumann spike in detonating high explosives

    NASA Astrophysics Data System (ADS)

    Sollier, A.; Bouyer, V.; Hébert, P.; Doucet, M.

    2016-06-01

    We present detonation wave profiles measured in T2 (97 wt. % TATB) and TX1 (52 wt. % TATB and 45 wt. % HMX) high explosives. The experiments consisted in initiating a detonation wave in a 15 mm diameter cylinder of explosive using an explosive wire detonator and an explosive booster. Free surface velocity wave profiles were measured at the explosive/air interface using a Photon Doppler Velocimetry system. We demonstrate that a comparison of these free surface wave profiles with those measured at explosive/window interfaces in similar conditions allows to bracket the von Neumann spike in a narrow range. For T2, our measurements show that the spike pressure lies between 35.9 and 40.1 GPa, whereas for TX1, it lies between 42.3 and 47.0 GPa. The numerical simulations performed in support to these measurements show that they can be used to calibrate reactive burn models and also to check the accuracy of the detonation products equation of state at low pressure.

  6. von Neumann Stability Analysis of Numerical Solution Schemes for 1D and 2D Euler Equations

    NASA Astrophysics Data System (ADS)

    Konangi, Santosh; Palakurthi, Nikhil Kumar; Ghia, Urmila

    2014-11-01

    A von Neumann stability analysis is conducted for numerical schemes for the full system of coupled, density-based 1D and 2D Euler equations, closed by an isentropic equation of state. The governing equations are discretized on a staggered grid, which permits equivalence to finite-volume discretization. Presently, first-order accurate spatial and temporal finite-difference techniques are analyzed. The momentum convection term is treated as explicit, semi-implicit or implicit. Density upwind bias is included in the spatial operator of the continuity equation. By combining the discretization techniques, ten solution schemes are formulated. For each scheme, unstable and stable regimes are identified through the stability analysis, and the maximum allowable CFL number is predicted. The predictions are verified for selected schemes, using the Riemann problem at incompressible and compressible Mach numbers. Very good agreement is obtained between the analytically predicted and ``experimentally'' observed CFL values for all cases, thereby validating the analysis. The demonstrated analysis provides an accurate indication of stability conditions for the Euler equations, in contrast to the simplistic conditions arising from model equations, such as the wave equation.

  7. Von Neumann entropy and phase distribution of two mode parametric amplifier interacting with a single atom

    NASA Astrophysics Data System (ADS)

    Abdalla, M. Sebawe; Obada, A.-S. F.; Abdel-Aty, M.

    2005-08-01

    In the present article, we introduce a Hamiltonian model that consists of two modes of the field in a perfect cavity to interact with a single two-level atom. The interaction between the fields has been taken into account and considered to be in the parametric amplifier form. The model in one hand can be regarded as a generalization of the Jaynes-Cummings model (JCM), however, in the other hand it can be considered as a generalization of the parametric amplifier model. Under a certain condition the exact solution to the Schrödinger equation is obtained. Employing this solution and for chosen values of different parameters we discuss numerically the atomic occupation probabilities as well as the degree of entanglement through the entropy of the field. The system shows superstructure phenomenon similar to that appeared from the effect of the Kerr-like medium on the Jaynes-Cummings model. The von Neumann entropy and phase distribution for both two-mode correlated and uncorrelated coherent states cases are also considered.

  8. Non-Equilibrium Zeldovich-Von Neumann-Doring Theory and Reactive Flow Modeling of Detonation

    SciTech Connect

    Tarver, C M; Forbes, J W; Urtiew, P A

    2002-05-02

    This paper discusses the Non-Equilibrium Zeldovich - von Neumann - Doring (NEZND) theory of self-sustaining detonation waves and the Ignition and Growth reactive flow model of shock initiation and detonation wave propagation in solid explosives. The NEZND theory identified the non-equilibrium excitation processes that precede and follow the exothermic decomposition of a large high explosive molecule into several small reaction product molecules. The thermal energy deposited by the leading shock wave must be distributed to the vibrational modes of the explosive molecule before chemical reactions can occur. The induction time for the onset of the initial endothermic reactions can be calculated using high pressure, high temperature transition state theory. Since the chemical energy is released well behind the leading shock front of a detonation wave, a physical mechanism is required for this chemical energy to reinforce the leading shock front and maintain its overall constant velocity. This mechanism is the amplification of pressure wavelets in the reaction zone by the process of de-excitation of the initially highly vibrationally excited reaction product molecules. This process leads to the development of the three-dimensional structure of detonation waves observed for all explosives. For practical predictions of shock initiation and detonation in hydrodynamic codes, phenomenological reactive flow models have been developed. The Ignition and Growth reactive flow model of shock initiation and detonation in solid explosives has been very successful in describing the overall flow measured by embedded gauges and laser interferometry. This reactive flow model uses pressure and compression dependent reaction rates, because time resolved experimental temperature data is not yet available. Since all chemical reaction rates are ultimately controlled by temperature, the next generation of reactive flow models will use temperature dependent reaction rates. Progress on a

  9. Boundaries, kinetic properties, and final domain structure of plane discrete uniform Poisson-Voronoi tessellations with von Neumann neighborhoods

    NASA Astrophysics Data System (ADS)

    Korobov, A.

    2009-03-01

    Discrete random tessellations appear not infrequently in describing nucleation and growth transformations. Generally, several non-Euclidean metrics are possible in this case. Previously [A. Korobov, Phys. Rev. B 76, 085430 (2007)] continual analogs of such tessellations have been studied. Here one of the simplest discrete varieties of the Kolmogorov-Johnson-Mehl-Avrami model, namely, the model with von Neumann neighborhoods, has been examined per se, i.e., without continualization. The tessellation is uniform in the sense that domain boundaries consist of tiles. Similarities and distinctions between discrete and continual models are discussed.

  10. Analytical reconsideration of the von Neumann paradox in the reflection of a shock wave over a wedge

    NASA Astrophysics Data System (ADS)

    Vasilev, Eugene I.; Elperin, Tov; Ben-Dor, Gabi

    2008-04-01

    The reflection of weak shock waves has been reconsidered analytically using shock polars. Based on the boundary condition across the slipstream, the solutions of the three-shock theory (3ST) were classified as "standard-3ST solutions" and "nonstandard-3ST solutions." It was shown that there are two situations in the nonstandard case: A situation whereby the 3ST provides solutions of which at least one is physical and a situation when the 3ST provides a solution which is not physical, and hence a reflection having a three-shock confluence is not possible. In addition, it is shown that there are initial conditions for which the 3ST does not provide any solution. In these situations, a four-wave theory, which is also presented in this study, replaces the 3ST. It is shown that four different wave configurations can exist in the weak shock wave reflection domain, a Mach reflection, a von Neumann reflection, a ?R (this reflection is not named yet!), and a modified Guderley reflection (GR). Recall that the wave configuration that was hypothesized by Guderley ["Considerations of the structure of mixed subsonic-supersonic flow patterns," Air Materiel Command Technical Report No. F-TR-2168-ND, ATI No. 22780, GS-AAF-Wright Field No. 39, U.S. Wright-Patterson Air Force Base, Dayton, OH (October 1947); Theorie Schallnaher Strömungen (Springer-Verlag, Berlin, 1957)] and later termed Guderley reflection did not include a slipstream (see Fig. 7). Our numerical study revealed that the wave structure proposed by Guderley must be complemented by a slipstream (see Fig. 4) in order to be relevant for explaining the von Neumann paradox. Hereafter, for simplicity, this modified GR wave configuration will be also termed Guderley reflection. The domains and transition boundaries between these four types of reflection are elucidated.

  11. Wonder or fake - investigations in the case of the stigmatisation of Therese Neumann von Konnersreuth.

    PubMed

    Rolf, Burkhard; Bayer, Birgit; Anslinger, Katja

    2006-03-01

    We investigated two compresses used by Therese Neumann (T.N.), a woman who lived from 1898 until 1962 in Konnersreuth, Germany. The compresses were soaked with blood during the appearance of stigmata on T.N.'s body on a Friday. T.N. became very popular among the faithful in Germany at this time. The question was whether this blood was from T.N. herself or from a family relative or an animal. The comparison of the HV1 and HV2 mtDNA sequence obtained from the compresses with the sequences from a reference sample from a maternally related niece of T.N. revealed an identity. Furthermore, we obtained a short tandem repeat (STR) profile from the bloodstains that were identical with the STR profile from a gummed envelope. The envelope contained a letter written by T.N. in the 1930s. Therefore, our investigations gave no indication for any manipulation. PMID:16158311

  12. Context-invariant quasi hidden variable (qHV) modelling of all joint von Neumann measurements for an arbitrary Hilbert space

    NASA Astrophysics Data System (ADS)

    Loubenets, Elena R.

    2015-03-01

    We prove the existence for each Hilbert space of the two new quasi hidden variable (qHV) models, statistically noncontextual and context-invariant, reproducing all the von Neumann joint probabilities via non-negative values of real-valued measures and all the quantum product expectations—via the qHV (classical-like) average of the product of the corresponding random variables. In a context-invariant model, a quantum observable X can be represented by a variety of random variables satisfying the functional condition required in quantum foundations but each of these random variables equivalently models X under all joint von Neumann measurements, regardless of their contexts. The proved existence of this model negates the general opinion that, in terms of random variables, the Hilbert space description of all the joint von Neumann measurements for dim H ≥ 3 can be reproduced only contextually. The existence of a statistically noncontextual qHV model, in particular, implies that every N-partite quantum state admits a local quasi hidden variable model introduced in Loubenets [J. Math. Phys. 53, 022201 (2012)]. The new results of the present paper point also to the generality of the quasi-classical probability model proposed in Loubenets [J. Phys. A: Math. Theor. 45, 185306 (2012)].

  13. Context-invariant quasi hidden variable (qHV) modelling of all joint von Neumann measurements for an arbitrary Hilbert space

    SciTech Connect

    Loubenets, Elena R.

    2015-03-15

    We prove the existence for each Hilbert space of the two new quasi hidden variable (qHV) models, statistically noncontextual and context-invariant, reproducing all the von Neumann joint probabilities via non-negative values of real-valued measures and all the quantum product expectations—via the qHV (classical-like) average of the product of the corresponding random variables. In a context-invariant model, a quantum observable X can be represented by a variety of random variables satisfying the functional condition required in quantum foundations but each of these random variables equivalently models X under all joint von Neumann measurements, regardless of their contexts. The proved existence of this model negates the general opinion that, in terms of random variables, the Hilbert space description of all the joint von Neumann measurements for dimH≥3 can be reproduced only contextually. The existence of a statistically noncontextual qHV model, in particular, implies that every N-partite quantum state admits a local quasi hidden variable model introduced in Loubenets [J. Math. Phys. 53, 022201 (2012)]. The new results of the present paper point also to the generality of the quasi-classical probability model proposed in Loubenets [J. Phys. A: Math. Theor. 45, 185306 (2012)].

  14. On the representation of elements of a von Neumann algebra in the form of finite sums of products of projections. III. Commutators in C*-algebras

    SciTech Connect

    Bikchentaev, A M

    2008-04-30

    It is proved that every skew-Hermitian element of any properly infinite von Neumann algebra can be represented in the form of a finite sum of commutators of projections in this algebra. A new commutation condition for projections in terms of their upper (lower) bound in the lattice of all projections of the algebra is obtained. For the full matrix algebra the set of operators with canonical trace zero is described in terms of finite sums of commutators of projections and the domain in which the trace is positive is described in terms of finite sums of pairwise products of projections. Applications to AF-algebras are obtained. Bibliography: 33 titles.

  15. Comparison between Utsu's and Vere-Jones' aftershocks model by means of a computer simulation based on the acceptance-rejection sampling of von Neumann

    NASA Astrophysics Data System (ADS)

    Reyes, J.; Morales-Esteban, A.; González, E.; Martínez-Álvarez, F.

    2016-07-01

    In this research, a new algorithm for generating a stochastic earthquake catalog is presented. The algorithm is based on the acceptance-rejection sampling of von Neumann. The result is a computer simulation of earthquakes based on the calculated statistical properties of each zone. Vere-Jones states that an earthquake sequence can be modeled as a series of random events. This is the model used in the proposed simulation. Contrariwise, Utsu indicates that the mainshocks are special geophysical events. The algorithm has been applied to zones of Chile, China, Spain, Japan, and the USA. This allows classifying the zones according to Vere-Jones' or Utsu's model. The results have been quantified relating the mainshock with the largest aftershock within the next 5 days (which has been named as Bath event). The results show that some zones fit Utsu's model and others Vere-Jones'. Finally, the fraction of seismic events that satisfy certain properties of magnitude and occurrence is analyzed.

  16. Using the concept of Chou's pseudo amino acid composition to predict protein subcellular localization: an approach by incorporating evolutionary information and von Neumann entropies.

    PubMed

    Zhang, Shao-Wu; Zhang, Yun-Long; Yang, Hui-Fang; Zhao, Chun-Hui; Pan, Quan

    2008-05-01

    The rapidly increasing number of sequence entering into the genome databank has called for the need for developing automated methods to analyze them. Information on the subcellular localization of new found protein sequences is important for helping to reveal their functions in time and conducting the study of system biology at the cellular level. Based on the concept of Chou's pseudo-amino acid composition, a series of useful information and techniques, such as residue conservation scores, von Neumann entropies, multi-scale energy, and weighted auto-correlation function were utilized to generate the pseudo-amino acid components for representing the protein samples. Based on such an infrastructure, a hybridization predictor was developed for identifying uncharacterized proteins among the following 12 subcellular localizations: chloroplast, cytoplasm, cytoskeleton, endoplasmic reticulum, extracell, Golgi apparatus, lysosome, mitochondria, nucleus, peroxisome, plasma membrane, and vacuole. Compared with the results reported by the previous investigators, higher success rates were obtained, suggesting that the current approach is quite promising, and may become a useful high-throughput tool in the relevant areas. PMID:18074191

  17. Non-Born-Oppenheimer Liouville-von Neumann Dynamics. Evolution of a Subsystem Controlled by Linear and Population-Driven Decay of Mixing with Decoherent and Coherent Switching.

    PubMed

    Zhu, Chaoyuan; Jasper, Ahren W; Truhlar, Donald G

    2005-07-01

    Electronic energy flow in an isolated molecular system involves coupling between the electronic and nuclear subsystems, and the coupled system evolves to a statistical mixture of pure states. In semiclassical theories, nuclear motion is treated using classical mechanics, and electronic motion is treated as an open quantal system coupled to a "bath" of nuclear coordinates. We have previously shown how this can be simulated by a time-dependent Schrödinger equation with coherent switching and decay of mixing, where the decay of mixing terms model the dissipative effect of the environment on the electronic subdynamics (i.e., on the reduced dynamics of the electronic subsystem). In the present paper we reformulate the problem as a Liouville-von Neumann equation of motion (i.e., we propagate the reduced density matrix of the electronic subsystem), and we introduce the assumption of first-order linear decay. We specifically examine the cases of equal relaxation times for both longitudinal (i.e., population) decay and transverse decay (i.e., dephasing) and of longitudinal relaxation only, yielding the linear decay of mixing (LDM) and the population-driven decay of mixing (PDDM) schemes, respectively. Because we do not generally know the basis in which coherence decays, that is, the pointer basis, we judge the semiclassical methods in part by their ability to give good results in both the adiabatic and diabatic bases. The accuracy in the prediction of physical observables is shown to be robust not only with respect to basis but also with respect to the way in which demixing is incorporated into the master equation for the density matrix. The success of the PDDM scheme is particularly interesting because it incorporates the least amount of decoherence (i.e., the PDDM scheme is the most similar of the methods discussed to the fully coherent semiclassical Ehrenfest method). For both the new and previous decay of mixing schemes, four kinds of decoherent state switching

  18. German-American Cultural Interaction in the Jacksonian Era: Six Unpublished Letters by Francis Lieber and John Pickering to Wilhelm von Humboldt.

    ERIC Educational Resources Information Center

    Mueller-Vollmer, Kurt

    1998-01-01

    Letters by German-American writer and political scientist Francis Lieber and American lawyer and linguist John Pickering to Wilhem von Humboldt in Berlin, published here for the first time, give insight into the cultural interaction between Germany and the United States during the Jacksonian era, and may open new perspectives for German-American…

  19. Analyzing Von Neumann machines using decentralized symmetries

    NASA Astrophysics Data System (ADS)

    Fang, Jie

    2013-10-01

    The artificial intelligence method to e-business is defined not only by the study of fiber-optic cables, but also by the unproven need for vacuum tubes. Given the current status of virtual archetypes, theorists clearly desire the exploration of semaphores, which embodies the compelling principles of cryptoanalysis. We present an algorithm for probabilistic theory (Buck), which we use to disprove that write-back caches can be made decentralized, lossless, and reliable.

  20. Carl Neumann's Contributions to Electrodynamics

    NASA Astrophysics Data System (ADS)

    Schlote, Karl-Heinz

    2004-09-01

    I examine the publications of Carl Neumann (1832 1925) on electrodynamics, which constitute a major part of his work and which illuminate his approach to mathematical physics. I show how Neumann contributed to physics at an important stage in its development and how his work led to a polemic with Hermann Helmholtz (1821 1894). Neumann advanced and extended the ideas of the Königsberg school of mathematical physics. His investigations were aimed at founding a mathematically exact physical theory of electrodynamics, following the approach of Carl G.J. Jacobi (1804 1851) on the foundation of a physical theory as outlined in Jacobi’s lectures on analytical mechanics. Neumann’s work also shows how he clung to principles that impeded him in appreciating and developing new ideas such as those on field theory that were proposed by Michael Faraday (1791 1867) and James Clerk Maxwell (1831 1879).

  1. The von Neumann paradox in weak shock reflection

    NASA Astrophysics Data System (ADS)

    Zakharian, A. R.; Brio, M.; Hunter, J. K.; Webb, G. M.

    2000-11-01

    We present a numerical solution of the Euler equations of gas dynamics for a weak-shock Mach reflection in a half-space. In our numerical solutions, the incident, reflected, and Mach shocks meet at a triple point, and there is a supersonic patch behind the triple point, as proposed by Guderley. A theoretical analysis supports the existence of an expansion fan at the triple point, in addition to the three shocks. This solution is in complete agreement with the numerical solution of the unsteady transonic small-disturbance equations obtained by Hunter & Brio (2000), which provides an asymptotic description of a weak-shock Mach reflection. The supersonic patch is extremely small, and this work is the first time it has been resolved in a numerical solution of the Euler equations. The numerical solution uses six levels of grid refinement around the triple point. A delicate combination of numerical techniques is required to minimize both the effects of numerical diffusion and the generation of numerical oscillations at grid interfaces and shocks.

  2. Genetics Home Reference: von Hippel-Lindau syndrome

    MedlinePlus

    ... Review. Citation on PubMed Maher ER, Neumann HP, Richard S. von Hippel-Lindau disease: a clinical and scientific ... on PubMed or Free article on PubMed Central Richard S, Graff J, Lindau J, Resche F. Von Hippel- ...

  3. Dr. von Braun at 'Wernher von Braun Day' Celebration

    NASA Technical Reports Server (NTRS)

    1970-01-01

    In 1970 Marshall Space Flight Center (MSFC) Director Dr. Wernher von Braun (right) was reassigned to NASA Headquarters to serve as Deputy Associate Administrator for Plarning. Prior to his transfer, Dr. von Braun was honored for his career in Huntsville, Alabama, with the celebration of 'Wernher von Braun Day.' Among those participating were Alabama Governor Albert Brewer (left) and Alabama Senator John Sparkman (center). (Courtesy of Huntsville/Madison County Public library)

  4. Spectral properties of ghost Neumann matrices

    SciTech Connect

    Bonora, L.; Santos, R. J. Scherer; Tolla, D. D.

    2008-05-15

    We continue the analysis of the ghost wedge states in the oscillator formalism by studying the spectral properties of the ghost matrices of Neumann coefficients. We show that the traditional spectral representation is not valid for these matrices and propose a new heuristic formula that allows one to reconstruct them from the knowledge of their eigenvalues and eigenvectors. It turns out that additional data, which we call boundary data, are needed in order to actually implement the reconstruction. In particular our result lends support to the conjecture that there exists a ghost three strings vertex with properties parallel to those of the matter three strings vertex.

  5. John Manke

    NASA Technical Reports Server (NTRS)

    1981-01-01

    On October 1, 1981, John A. Manke was named to head the Directorate of Flight Operations, Ames Research Center, which resulted from the consolidation of NASA's Dryden Flight Research Center at Edwards, California, and Ames Research Center, Moffett Field, California. He also served as site manager of the NASA Ames-Dryden Flight Research Facility. Prior to this assignment, he served as Director of the Flight Operations and Support Directorate at Dryden. Manke attended the University of South Dakota before joining the U.S. Navy in 1951. He graduated from Marquette University at Milwaukee, Wisconsin, in 1956 with a Bachelor Degree in Electrical Engineering. While at school he was selected for the NROTC program and after graduating in 1956 entered flight training and served as a fighter pilot with the U.S. Marine Corps. John left the service in 1960, and prior to joining NASA, worked for Honeywell Corporation as a test engineer. John joined Dryden in 1962 as a research engineer and later became a research pilot, testing advanced craft such as the wingless lifting bodies, forerunners of the Space Shuttle. He was project pilot on the X-24B and also flew the M-2, HL-10 and the X-24A lifting bodies. Manke retired on April 27, 1984. John is a member of the Society of Experimental Test Pilots. He has been honored with two NASA Medals of Outstanding Leadership, two NASA Medals for Exceptional Service and was selected for the Aerospace Walk of Honor in 1997.

  6. John Napier

    ERIC Educational Resources Information Center

    Bryant, Kylie; Scott, Paul

    2004-01-01

    John Napier was born in 1550 in the Tower of Merchiston, near Edinburgh, Scotland. Napier's work on logarithms greatly influenced the work that was to be done in the future. The logarithm's ability to simplify calculations meant that Kepler and many others were able to find the relationships and formulas for motion of bodies. In turn, Kepler's…

  7. Diffraction for a Neumann boundary condition

    SciTech Connect

    Lafitte, O.

    1997-11-01

    Let 0 be a bounded open set in R{sup n} and P be a constant coefficient operator of order 2 in R{sup n} x R{sub t} such that (P, {Omega}{sup c}) admits a strictly diffractive point. We calculate in this paper the principal symbol of the operator K transforming {partial_derivative}{sub n}u into u/{sub {partial_derivative}{Omega}} for a solution u of Pu = 0 in the neighborhood of a strictly diffractive point {rho}{sub 0} for (P, {Omega}{sup c}). We deduce from this calculation the principal symbol of the wave diffracted by a strictly convex analytic obstacle with a Neumann boundary condition. This result is used to calculate the electromagnetic wave diffracted by a perfectly conducting body. 7 refs., 2 figs.

  8. Ampere-Neumann electrodynamics of metals

    SciTech Connect

    Graneau, P.

    1985-01-01

    Maxwell described Ampere's force law as the cardinal formula of electrodynamics. This law predicts longitudinal mechanical forces along current streamlines in metallic conductors. The Ampere forces set up tension in wires and busbars and compression in liquid metal. At normal current densities they are negligible but, increasing with the square of current, they become dominant in pulse power circuits. Ampere tension and compression have been revealed by exploding wire experiments, in liquid metal jets at solid - liquid interfaces, and with an electrodynamic pendulum. Ampere stresses are already playing an important role in the development of railguns, fuses, current limiters, opening switches, pulse magnets, and a host of other pulse-power devices. This book outlines the electrodynamic action-at-a-distance theory developed by Ampere, Neumann, Weber and, to some extent, by Maxwell. One chapter describes the 20th century extensions of the theory by Graneau and others.

  9. Strong curvature effects in Neumann wave problems

    SciTech Connect

    Willatzen, M.; Pors, A.; Gravesen, J.

    2012-08-15

    Waveguide phenomena play a major role in basic sciences and engineering. The Helmholtz equation is the governing equation for the electric field in electromagnetic wave propagation and the acoustic pressure in the study of pressure dynamics. The Schroedinger equation simplifies to the Helmholtz equation for a quantum-mechanical particle confined by infinite barriers relevant in semiconductor physics. With this in mind and the interest to tailor waveguides towards a desired spectrum and modal pattern structure in classical structures and nanostructures, it becomes increasingly important to understand the influence of curvature effects in waveguides. In this work, we demonstrate analytically strong curvature effects for the eigenvalue spectrum of the Helmholtz equation with Neumann boundary conditions in cases where the waveguide cross section is a circular sector. It is found that the linear-in-curvature contribution originates from parity symmetry breaking of eigenstates in circular-sector tori and hence vanishes in a torus with a complete circular cross section. The same strong curvature effect is not present in waveguides subject to Dirichlet boundary conditions where curvature contributions contribute to second-order in the curvature only. We demonstrate this finding by considering wave propagation in a circular-sector torus corresponding to Neumann and Dirichlet boundary conditions, respectively. Results for relative eigenfrequency shifts and modes are determined and compared with three-dimensional finite element method results. Good agreement is found between the present analytical method using a combination of differential geometry with perturbation theory and finite element results for a large range of curvature ratios.

  10. Strong curvature effects in Neumann wave problems

    NASA Astrophysics Data System (ADS)

    Willatzen, M.; Pors, A.; Gravesen, J.

    2012-08-01

    Waveguide phenomena play a major role in basic sciences and engineering. The Helmholtz equation is the governing equation for the electric field in electromagnetic wave propagation and the acoustic pressure in the study of pressure dynamics. The Schrödinger equation simplifies to the Helmholtz equation for a quantum-mechanical particle confined by infinite barriers relevant in semiconductor physics. With this in mind and the interest to tailor waveguides towards a desired spectrum and modal pattern structure in classical structures and nanostructures, it becomes increasingly important to understand the influence of curvature effects in waveguides. In this work, we demonstrate analytically strong curvature effects for the eigenvalue spectrum of the Helmholtz equation with Neumann boundary conditions in cases where the waveguide cross section is a circular sector. It is found that the linear-in-curvature contribution originates from parity symmetry breaking of eigenstates in circular-sector tori and hence vanishes in a torus with a complete circular cross section. The same strong curvature effect is not present in waveguides subject to Dirichlet boundary conditions where curvature contributions contribute to second-order in the curvature only. We demonstrate this finding by considering wave propagation in a circular-sector torus corresponding to Neumann and Dirichlet boundary conditions, respectively. Results for relative eigenfrequency shifts and modes are determined and compared with three-dimensional finite element method results. Good agreement is found between the present analytical method using a combination of differential geometry with perturbation theory and finite element results for a large range of curvature ratios.

  11. Neumann domination for the Yang-Mills heat equation

    NASA Astrophysics Data System (ADS)

    Charalambous, Nelia; Gross, Leonard

    2015-07-01

    Long time existence and uniqueness of solutions to the Yang-Mills heat equation have been proven over a compact 3-manifold with boundary for initial data of finite energy. In the present paper, we improve on previous estimates by using a Neumann domination technique that allows us to get much better pointwise bounds on the magnetic field. As in the earlier work, we focus on Dirichlet, Neumann, and Marini boundary conditions. In addition, we show that the Wilson Loop functions, gauge invariantly regularized, converge as the parabolic time goes to infinity.

  12. St. John's Wort (image)

    MedlinePlus

    The herb St. John's Wort is believed to be helpful in relieving mild to moderate depression, but should only be taken under a physician's supervision. St. John's Wort may clash with other medications or foods ...

  13. St. John's Wort

    MedlinePlus

    ... 359–366. St. John's wort. Natural Medicines Comprehensive Database Web site. Accessed at www.naturaldatabase.com on February ... St. John's wort ( Hypericum perforatum L.). Natural Standard Database Web site. Accessed at www.naturalstandard.com on February ...

  14. On Neumann and Poincare problems for Laplace equation

    NASA Astrophysics Data System (ADS)

    Ryazanov, Vladimir

    2016-08-01

    It is proved the existence of nonclassical solutions of the Neumann problem for the harmonic functions in the Jordan rectifiable domains with arbitrary measurable boundary distributions of normal derivatives. The same is stated for a special case of the Poincare problem on directional derivatives. Moreover, it is shown that the spaces of the found solutions have the infinite dimension.

  15. Eigenvalues of the Neumann Laplacian in symmetric regions

    NASA Astrophysics Data System (ADS)

    Marrocos, Marcus A. M.; Pereira, Antônio L.

    2015-11-01

    In this work, we are concerned with the multiplicity of the eigenvalues of the Neumann Laplacian in regions of ℝn which are invariant under the natural action of a compact subgroup G of O(n). We give a partial positive answer (in the Neumann case) to a conjecture of Arnol'd [Funct. Anal. Appl. 6, 94-101 (1972)] on the transversality of the transformation given by the Dirichlet integral to the stratification in the space of quadratic forms according to the multiplicities of the eigenvalues. We show, for some classes of subgroups of O(n) that, generically in the set of G - invariant, C 2 -regions, the action is irreducible in each eigenspace Ker(Δ + λ). These classes include finite subgroups with irreducible representations of dimension not greater than 2 and, in the case n = 2, any compact subgroup of O(2). We also obtain some partial results for general compact subgroups of O(n).

  16. John Glenn - Mini Biography

    NASA Technical Reports Server (NTRS)

    1963-01-01

    Mini Biography of John Glenn, as it was up to 1962. From film to tape transfer of the film 'Friendship 7 - John Glenn' Depicts the historical orbital flight of John Glenn aboard 'Friendship 7', launched on February 20, 1962. Footage of staff at tracking stations worldwide and at Goddard Space Flight Center. Launch from cape canaveral. Flight tracking, re-entry, landing and recovery of Friendship 7.

  17. John Glenn: Friendship 7 Splashdown

    NASA Technical Reports Server (NTRS)

    1963-01-01

    Splasdown of Freindship 7 From: The John Glenn Story: Summary of astronaut John Glenn's flying career, from naval aviation training to space flight. The Mercury project is featured as John Glenn flies the Friendship 7 spacecraft. President John F. Kennedy presents the NASA Distinguished service Medal to Astronaut John Glenn.

  18. Accurate quantum dynamics calculations using symmetrized Gaussians on a doubly dense Von Neumann lattice

    SciTech Connect

    Halverson, Thomas; Poirier, Bill

    2012-12-14

    In a series of earlier articles [B. Poirier, J. Theor. Comput. Chem. 2, 65 (2003); B. Poirier and A. Salam, J. Chem. Phys. 121, 1690 (2004); and ibid. 121, 1704 (2004)], a new method was introduced for performing exact quantum dynamics calculations. The method uses a 'weylet' basis set (orthogonalized Weyl-Heisenberg wavelets) combined with phase space truncation, to defeat the exponential scaling of CPU effort with system dimensionality-the first method ever able to achieve this long-standing goal. Here, we develop another such method, which uses a much more convenient basis of momentum-symmetrized Gaussians. Despite being non-orthogonal, symmetrized Gaussians are collectively local, allowing for effective phase space truncation. A dimension-independent code for computing energy eigenstates of both coupled and uncoupled systems has been created, exploiting massively parallel algorithms. Results are presented for model isotropic uncoupled harmonic oscillators and coupled anharmonic oscillators up to 27 dimensions. These are compared with the previous weylet calculations (uncoupled harmonic oscillators up to 15 dimensions), and found to be essentially just as efficient. Coupled system results are also compared to corresponding exact results obtained using a harmonic oscillator basis, and also to approximate results obtained using first-order perturbation theory up to the maximum dimensionality for which the latter may be feasibly obtained (four dimensions).

  19. Coherent state transforms and the Mackey-Stone-Von Neumann theorem

    NASA Astrophysics Data System (ADS)

    Kirwin, William D.; Mourão, José M.; Nunes, João P.

    2014-10-01

    Mackey showed that for a compact Lie group K, the pair (K, C 0(K)) has a unique non-trivial irreducible covariant pair of representations. We study the relevance of this result to the unitary equivalence of quantizations for an infinite-dimensional family of K × K invariant polarizations on T*K. The Kähler polarizations in the family are generated by (complex) time-τ Hamiltonian flows applied to the (Schrödinger) vertical real polarization. The unitary equivalence of the corresponding quantizations of T*K is then studied by considering covariant pairs of representations of K defined by geometric prequantization and of representations of C 0(K) defined via Heisenberg time-(-τ) evolution followed by time-(+τ) geometric-quantization-induced evolution. We show that in the semiclassical and large imaginary time limits, the unitary transform whose existence is guaranteed by Mackey's theorem can be approximated by composition of the time-(+τ) geometric-quantization-induced evolution with the time-(-τ) evolution associated with the momentum space [W. D. Kirwin and S. Wu, "Momentum space for compact Lie groups and the Peter-Weyl theorem" (unpublished)] quantization of the Hamiltonian function generating the flow. In the case of quadratic Hamiltonians, this asymptotic result is exact and unitary equivalence between quantizations is achieved by identifying the Heisenberg imaginary time evolution with heat operator evolution, in accordance with the coherent state transform of Hall.

  20. Accurate quantum dynamics calculations using symmetrized Gaussians on a doubly dense Von Neumann lattice

    NASA Astrophysics Data System (ADS)

    Halverson, Thomas; Poirier, Bill

    2012-12-01

    In a series of earlier articles [B. Poirier, J. Theor. Comput. Chem. 2, 65 (2003);, 10.1142/S0219633603000380 B. Poirier and A. Salam, J. Chem. Phys. 121, 1690 (2004);, 10.1063/1.1767511 B. Poirier and A. Salam, J. Chem. Phys. 121, 1704 (2004), 10.1063/1.1767512], a new method was introduced for performing exact quantum dynamics calculations. The method uses a "weylet" basis set (orthogonalized Weyl-Heisenberg wavelets) combined with phase space truncation, to defeat the exponential scaling of CPU effort with system dimensionality—the first method ever able to achieve this long-standing goal. Here, we develop another such method, which uses a much more convenient basis of momentum-symmetrized Gaussians. Despite being non-orthogonal, symmetrized Gaussians are collectively local, allowing for effective phase space truncation. A dimension-independent code for computing energy eigenstates of both coupled and uncoupled systems has been created, exploiting massively parallel algorithms. Results are presented for model isotropic uncoupled harmonic oscillators and coupled anharmonic oscillators up to 27 dimensions. These are compared with the previous weylet calculations (uncoupled harmonic oscillators up to 15 dimensions), and found to be essentially just as efficient. Coupled system results are also compared to corresponding exact results obtained using a harmonic oscillator basis, and also to approximate results obtained using first-order perturbation theory up to the maximum dimensionality for which the latter may be feasibly obtained (four dimensions).

  1. Accurate quantum dynamics calculations using symmetrized Gaussians on a doubly dense Von Neumann lattice.

    PubMed

    Halverson, Thomas; Poirier, Bill

    2012-12-14

    In a series of earlier articles [B. Poirier, J. Theor. Comput. Chem. 2, 65 (2003); B. Poirier and A. Salam, J. Chem. Phys. 121, 1690 (2004); and ibid. 121, 1704 (2004)], a new method was introduced for performing exact quantum dynamics calculations. The method uses a "weylet" basis set (orthogonalized Weyl-Heisenberg wavelets) combined with phase space truncation, to defeat the exponential scaling of CPU effort with system dimensionality--the first method ever able to achieve this long-standing goal. Here, we develop another such method, which uses a much more convenient basis of momentum-symmetrized Gaussians. Despite being non-orthogonal, symmetrized Gaussians are collectively local, allowing for effective phase space truncation. A dimension-independent code for computing energy eigenstates of both coupled and uncoupled systems has been created, exploiting massively parallel algorithms. Results are presented for model isotropic uncoupled harmonic oscillators and coupled anharmonic oscillators up to 27 dimensions. These are compared with the previous weylet calculations (uncoupled harmonic oscillators up to 15 dimensions), and found to be essentially just as efficient. Coupled system results are also compared to corresponding exact results obtained using a harmonic oscillator basis, and also to approximate results obtained using first-order perturbation theory up to the maximum dimensionality for which the latter may be feasibly obtained (four dimensions). PMID:23248981

  2. Jasper Johns' Painted Words.

    ERIC Educational Resources Information Center

    Levinger, Esther

    1989-01-01

    States that the painted words in Jasper Johns' art act in two different capacities: concealed words partake in the artist's interrogation of visual perception; and visible painted words question classical representation. Argues that words are Johns' means of critiquing modernism. (RS)

  3. John Dewey, an Appreciation

    ERIC Educational Resources Information Center

    Clopton, Robert W.

    2015-01-01

    The subject of the annual Presidential address of Phi Kappa Phi, presented on May 8, 1962, was John Dewey. Dewey is identified in the public mind chiefly as an educational philosopher. In this address, the author describes the life and work of John Dewey as an indefatigable student of life whose interests ranged, like those of Aristotle, over the…

  4. The Unretiring John Krumboltz

    ERIC Educational Resources Information Center

    LaFromboise, Teresa D.; Neumann, Harly

    2002-01-01

    John D. Krumboltz continues to contribute to the field of counseling psychology, including the subspecialty of career counseling, after five decades of professional experience. Inspired by B. F. Skinner, John operationalized a behavioral approach to counseling. After 4 years at Michigan State University, where he initiated research on programmed…

  5. John Glenn OK

    NASA Technical Reports Server (NTRS)

    1962-01-01

    Astronaut John Glenn and technicians inspect artwork that will be painted on the outside of his Mercury spacecraft. John Glenn nicknamed his capsule 'Friendship 7'. On February 20, 1962 astronaut John H. Glenn Jr. lifted off into space aboard his Mercury Atlas (MA-6) rocket and became the first American to orbit the Earth. After orbiting the Earth 3 times, Friendship 7 landed in the Atlantic Ocean 4 hours, 55 minutes and 23 seconds later, just East of Grand Turk Island in the Bahamas. Glenn and his capsule were recovered by the Navy Destroyer Noa, 21 minutes after splashdown.

  6. Astronaut John Young's Career

    NASA Video Gallery

    John Young served as a NASA astronaut for over four decades, flying on Gemini, Apollo and the Space Shuttle. He walked on the moon during Apollo 16 in 1972 and commanded the first shuttle mission, ...

  7. John Henry: Then and Now.

    ERIC Educational Resources Information Center

    Nikola-Lisa, W.

    1998-01-01

    Compares three children's books retelling the legend of John Henry: "John Henry: An American Legend" by Ezra Jack Keats (1965), "John Henry" by Julius Lester (1994), and "The Legend of John Henry" by Terry Small (1994). Differences in imagery, language, symbolism, and themes are discussed. (MAK)

  8. Theodore von Karman

    NASA Technical Reports Server (NTRS)

    1950-01-01

    Dr. Theodore von Karman, co-founder of the Jet Propulsion Laboratory (JPL) Pasadena, California was an aeronautical theoretician. His contributions in the fields of aerodynamics and aeronautical engineering are well documented and well known to every aerospace engineer. He was the first winner of the prestigious U.S. Medal of Science presented to him by President John F. Kennedy. As well as being co-founder of JPL, he also was principal founder of a major rocket propulsion firm (Aerojet-General Corp.), the top science advisor to the U.S. Air Force during its transition to jet propulsion aircraft and the top science advisor to NATO. He was, during much of this time, the fountainhead of aerodynamic thought as head of the Guggenheim Aeronautical Laboratory at the California Institute of Technology (GALCIT) in Pasadena, California. In the May 1956 issue of the Journal of Aeronautical Sciences, it was said of him that 'No other man has had so great an impact on the development of aeronautical science in this country. Hundreds of young men became his students and scientific collaborators and were inspired to greater effort.' Dr. William H. Pickering, then director of JPL said in 1960 'We wouldn't have an aeronautical science as we know it today, if it weren't for Dr. Thoedore von Karman.' Under his guidance, Caltech's 10 foot wind tunnel was designed, built and operated. Industry firms such as Douglas, Northrop, Hughes, Lockheed, North American, Vultee and Consolidated all tested new aeronautical designs and concepts in GALCIT's tunnel. Even Boeing's own high-speed wind tunnel was heavily influenced by suggestions from von Karman. The National Advisory Committee for Aeronautics (NACA) became so concerned about GALCIT's growing influence over West coast aviation, it erected the Ames Laboratory in Sunnyvale, California in part to deter an ever widening aeronautical gap that had formed between NACA and GALCIT. From 1936 to 1940, Caltech stood alone as the only university

  9. Dirichlet and Neumann eigenvalues for half-plane magnetic Hamiltonians

    NASA Astrophysics Data System (ADS)

    Bruneau, Vincent; Miranda, Pablo; Raikov, Georgi

    2014-02-01

    Let H0,D (respectively, H0,N) be the Schrödinger operator in constant magnetic field on the half-plane with Dirichlet (respectively, Neumann) boundary conditions, and let Hℓ := H0,ℓ - V, ℓ = D, N, where the scalar potential V is non-negative, bounded, does not vanish identically, and decays at infinity. We compare the distribution of the eigenvalues of HD and HN below the respective infima of the essential spectra. To this end, we construct effective Hamiltonians which govern the asymptotic behavior of the discrete spectrum of Hℓ near inf σess(Hℓ) = inf σ(H0,ℓ), ℓ = D, N. Applying these Hamiltonians, we show that σdisc(HD) is infinite even if V has a compact support, while σdisc(HN) could be finite or infinite depending on the decay rate of V.

  10. Commemorating John Dyson

    NASA Astrophysics Data System (ADS)

    Pittard, Julian M.

    2015-03-01

    John Dyson was born on the 7th January 1941 in Meltham Mills, West Yorkshire, England, and later grew up in Harrogate and Leeds. The proudest moment of John's early life was meeting Freddie Trueman, who became one of the greatest fast bowlers of English cricket. John used a state scholarship to study at Kings College London, after hearing a radio lecture by D. M. McKay. He received a first class BSc Special Honours Degree in Physics in 1962, and began a Ph.D. at the University of Manchester Department of Astronomy after being attracted to astronomy by an article of Zdenek Kopal in the semi-popular journal New Scientist. John soon started work with Franz Kahn, and studied the possibility that the broad emission lines seen from the Orion Nebula were due to flows driven by the photoevaporation of neutral globules embedded in a HII region. John's thesis was entitled ``The Age and Dynamics of the Orion Nebula`` and he passed his oral examination on 28th February 1966.

  11. Dr. von Braun, Mayor Searcy, and General Medaris

    NASA Technical Reports Server (NTRS)

    1959-01-01

    Dr. Wernher von Braun, Director of the U.S. Army Ballistic Missile Agency's (ABMA) Development Operations Division, talks to Huntsville Mayor R. B. 'Speck' Searcy, center, and Army Ordnance Missile Command (ARMC) Major General John B. Medaris, right, during 'Moon Day' celebrations in downtown Huntsville, Alabama. (Courtesy of Huntsville/Madison County Public Library)

  12. In AppreciationThe Depth and Breadth of John Bell's Physics

    NASA Astrophysics Data System (ADS)

    Jackiw, Roman; Shimony, Abner

    This essay surveys the work of John Stewart Bell, one of the great physicists of the twentieth century. Section 1 is a brief biography, tracing his career from working-class origins and undergraduate training in Belfast, Northern Ireland, to research in accelerator and nuclear physics in the British national laboratories at Harwell and Malvern, to his profound research on elementary particle physics as a member of the Theory Group at CERN and his equally profound ``hobby'' of investigating the foundations of quantum mechanics. Section 2 concerns this hobby, which began in his discontent with Bohr's and Heisenberg's analyses of the measurement process. He was attracted to the program of hidden variables interpretations, but he revolutionized the foundations of quantum mechanics by a powerful negative result: that no hidden variables theory that is ``local'' (in a clear and well-motivated sense) can agree with all the correlations predicted by quantum mechanics regarding well-separated systems. He further deepened the foundations of quantum mechanics by penetrating conceptual analyses of results concerning measurement theory of von Neumann, de Broglie and Bohm, Gleason, Jauch and Piron, Everett, and Ghirardi-Rimini-Weber. Bell's work in particle theory (Section 3) began with a proof of the CPT theorem in his doctoral dissertation, followed by investigations of the phenomenology of CP-violating experiments. At CERN Bell investigated the commutation relations in current algebras from various standpoints. The failure of current algebra combined with partially conserved current algebra to permit the experimentally observed decay of the neutral pi-meson into two photons stimulated the discovery by Bell and Jackiw of anomalous or quantal symmetry breaking, which has numerous implications for elementary particle phenomena. Other late investigations of Bell on elementary particle physics were bound states in quantum chromodynamics (in collaboration with Bertlmann) and

  13. Who Killed John Keats?

    ERIC Educational Resources Information Center

    Leal, Amy

    2007-01-01

    Two months before he died, John Keats claimed he had been poisoned. Although most scholars and biographers have attributed Keats's fears of persecution, betrayal, and murder to consumptive dementia, Keats's suspicions had begun long before 1820 and were not without some justification. In this article, the author talks about the death of John…

  14. John Glenn's Space Ride.

    ERIC Educational Resources Information Center

    Schamel, Wynell; Potter, Lee Ann

    1998-01-01

    Reviews the accomplishments of John Glenn as a pilot, astronaut, senator, and pioneer in relation to his 1998 flight that made him the oldest person to ever travel into space. Includes photographs for students to study, and recommends classroom activities related to Glenn's career. (DSK)

  15. John Carroll University

    ERIC Educational Resources Information Center

    Dean, Kathleen Lis; Rombalski, Patrick; O'Dell, Kyle

    2009-01-01

    John Carroll University (JCU) is a Jesuit Catholic institution located in University Heights, approximately 10 miles east of Cleveland, Ohio. Founded in 1888, the university has a population of 3,400 undergraduates and 800 graduate students. The Division of Student Affairs at JCU comprises 11 units. The mission of the division is the same as that…

  16. Astronaut John H. Glenn

    NASA Technical Reports Server (NTRS)

    1959-01-01

    Astronaut John H. Glenn, one of the original seven astronauts for Mercury Project selected by NASA on April 27, 1959. The MA-6 mission, boosted by the Mercury-Atlas vehicle, was the first manned orbital launch by the United States, and carried Astronaut Glenn aboard the Friendship 7 spacecraft to orbit the Earth.

  17. Dedication: John Reuben Clark.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Volume 40 of Horticultural reviews is dedicated to John Reuben Clark (University of Arkansas) for his outstanding contributions to horticulture. While known particularly for his impact on blackberry, blueberry, table grape, and peach cultivar development, he has also been a strong and enthusiastic v...

  18. John Galen Howard.

    ERIC Educational Resources Information Center

    Draper, Joan

    1979-01-01

    A biographical sketch of John Galen Howard, founder of the Department of Architecture at the University of California at Berkeley, is presented. Howard's conservative outlook and idealistic nature are examined and his influence on the curriculum at the university is traced. (PHR)

  19. John C. Houbolt

    NASA Technical Reports Server (NTRS)

    1962-01-01

    John C. Houbolt at blackboard, showing his space rendezvous concept for lunar landings. Lunar Orbital Rendezvous (LOR) would be used in the Apollo program. Although Houbolt did not invent the idea of LOR, he was the person most responsible for pushing it at NASA.

  20. Peter Pindar (John Wolcot).

    ERIC Educational Resources Information Center

    Vales, Robert L.

    This book is designed as an introduction to John Wolcot's works for the general reader, the college student, and the college teacher. Wolcot, whose pen name was Peter Pindar, wrote topical satire on public personalities of the eighteenth century, and his methods of criticism are the motif which guides each chapter and which unites all the satires…

  1. The John Muir Award.

    ERIC Educational Resources Information Center

    White, Graham

    2002-01-01

    The John Muir Award was established in the United Kingdom to respond to minimal environmental awareness, especially among youth. The Award has three levels of effort; all involve discovering a wild place, exploring its wildness, helping to conserve it, and sharing the experience with a wider audience. There is an effort to establish the award in…

  2. John Cage Discusses Fluxus.

    ERIC Educational Resources Information Center

    Snyder, Ellsworth

    1992-01-01

    Presents an informal discussion with composer John Cage which includes his response to George Maciunas' work, his recollections of Marcel Duchamp, the complex relationship between inelegant material and revealing works of art, neo-Dada and neo-Fluxus, Wittgenstein and the artist's ultimate responsibility to initiate a change in the viewer or…

  3. A novel formulation for Neumann inflow boundary conditions in biomechanics.

    PubMed

    Gravemeier, Volker; Comerford, Andrew; Yoshihara, Lena; Ismail, Mahmoud; Wall, Wolfgang A

    2012-05-01

    Neumann boundary conditions prescribing the total momentum flux at inflow boundaries of biomechanical problems are proposed in this study. This approach enables the simultaneous application of velocity/flow rate and pressure curves at inflow boundaries. As the basic numerical method, a residual-based variational multiscale (or stabilized) finite element method is presented. The focus of the numerical examples in this work is on respiratory flows with complete flow reversals. However, the proposed formulation is just as well suited for cardiovascular flow problems with partial retrograde flow. Instabilities, which were reported for such problems in the literature, are resolved by the present approach without requiring the additional consideration of a Lagrange multiplier technique. The suitability of the approach is demonstrated for two respiratory flow examples, a rather simple tube and complex tracheobronchial airways (up to the fourth generation, segmented from end-expiratory CT images). For the latter example, the boundary conditions are generated from mechanical ventilation data obtained from an intensive care unit patient suffering from acute lung injury. For the tube, analytical pressure profiles can be replicated, and for the tracheobronchial airways, a correct distribution of the prescribed total momentum flux at the inflow boundary into velocity and pressure part is observed. PMID:25099458

  4. Finite temperature Casimir effect for a massless fractional Klein-Gordon field with fractional Neumann conditions

    SciTech Connect

    Eab, C. H.; Lim, S. C.; Teo, L. P.

    2007-08-15

    This paper studies the Casimir effect due to fractional massless Klein-Gordon field confined to parallel plates. A new kind of boundary condition called fractional Neumann condition which involves vanishing fractional derivatives of the field is introduced. The fractional Neumann condition allows the interpolation of Dirichlet and Neumann conditions imposed on the two plates. There exists a transition value in the difference between the orders of the fractional Neumann conditions for which the Casimir force changes from attractive to repulsive. Low and high temperature limits of Casimir energy and pressure are obtained. For sufficiently high temperature, these quantities are dominated by terms independent of the boundary conditions. Finally, validity of the temperature inversion symmetry for various boundary conditions is discussed.

  5. John Glenn: His first Flying Lesson Remembered

    NASA Technical Reports Server (NTRS)

    1971-01-01

    Pilot Harry Clever remembers giving John Glenn his first flying lesson. From: The John Glenn Story: Summary of astronaut John Glenn's flying career, from naval aviation training to space flight. The Mercury project is featured as John Glenn flies the Friendship 7 spacecraft. President John F. Kennedy presents the NASA Distinguished service Medal to Astronaught John Glenn.

  6. John Keats and tuberculosis.

    PubMed

    Radetsky, M

    2001-05-01

    John Keats was trained as an apothecary, the general practitioner of the day. Precocious in his sensibilities and fluent in his imagery, he also was the model of the romantic poet. That he was a physician and a poet makes his early death from tuberculosis poignant and revealing. This history traces his life and death against the backdrop of medicine at the turn of the 19th century. PMID:11368115

  7. Oliver St John Gogarty.

    PubMed

    Clarke, R W

    1997-01-01

    Oliver St John Gogarty--Otolaryngologist to fashionable Edwardian Dublin--was a distinguished poet and a Senator in the fledgling Irish Free State after its establishment in 1922. He numbered amongst his acquaintances the poet William Butler Yeats, the novelist James Joyce and a host of political and literary persona who helped to shape modern Ireland. He was satirised as 'stately plump Buck Mulligan' in Joyce's novel Ulysses. PMID:9292124

  8. John McCain

    ERIC Educational Resources Information Center

    Phi Delta Kappan, 2008

    2008-01-01

    This article presents speeches describing John McCain's position on education posted on the McCain campaign's official web site, www.johnmccain.com. These include McCain's speech to LaRaza convention, July 14; McCain's speech to the NAACP, July 16; McCain's speech at the Greater Columbus (Ohio) Convention Center, May 15; and McCain's speech at…

  9. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Dr. Wernher von Braun with Dr. Eberhard Rees and R.W. Cook at a press conference concerning Dr. Von Braun's assignment to NASA headquarters and Dr. Rees' subsequent assignment as Marshall Center director.

  10. John Campbell Begg

    NASA Astrophysics Data System (ADS)

    Campbell, Robert

    2002-03-01

    John Campbell Begg born in Dunedin in 1876 was the son of Alexander Campbell Begg and Katherine Begg, early Otago settlers. He studied physics and philosophy at the University of Otago before turning to business and rural pursuits. He died in Dunedin in 1965 age 89. The Begg family were foundation members of the Otago Astronomical Society. Visits to the Tanna Hill Observatory were made in 1915. The astronomical observatory which stands in Robin Hood Park, Roslyn, Dunedin bears his name; Beverly Begg Observatory

  11. John Nash, game theory, and the schizophrenic brain.

    PubMed

    Capps, Donald

    2011-03-01

    This article focuses on John Nash, recipient of the Nobel Prize in Economics in 1994, and subject of the Award winning 2001 film A Beautiful Mind, who was diagnosed with paranoid schizophrenia in 1958 at the age of 29. After presenting an account of the emergence, course, and eventual remission of his illness, the article argues for the relevance of his contribution to game theory, known as the Nash equilibrium, for which he received the Nobel Prize, to research studies of the schizophrenic brain and how it deviates from the normal brain. The case is made that the Nash equilibrium is descriptive of the normal brain, whereas the game theory formulated by John van Neumann, which Nash's theory challenges, is descriptive of the schizophrenic brain. The fact that Nash and his colleagues in mathematics did not make the association between his contributions to mathematics and his mental breakdown and that his later recovery exemplified the validity of this contribution are noted and discussed. Religious themes in his delusional system, including his view of himself as a secret messianic figure and the biblical Esau, are interpreted in light of these competing game theories and the dysfunctions of the schizophrenic brain. His recognition that his return to normalcy came at the price of his sense of being in relation to the cosmos is also noted. PMID:19862621

  12. Light amplification using semiconductors

    SciTech Connect

    Dupuis, R.D.

    1987-06-01

    During the summer of 1953, John von Neumann discussed his ideas concerning light amplification using semiconductors with Edward Teller. In September of that year, von Neumann sent a manuscript containing his ideas and calculations on this subject to Teller for his comments. To the best of our knowledge, von Neumann did not take time to work further on these ideas, and the manuscript remained unpublished. These previously unpublished writings of John von Neumann on the subject of light amplification in semiconductors are printed as a service to the laser community. While von Neumann's original manuscript and his letter to Teller are available to anyone who visits the Library of Congress, it is much more convenient to have this paper appear in an archival journal.

  13. Marcel Breuer at Saint John's

    ERIC Educational Resources Information Center

    Carlson, Scott

    2008-01-01

    A visitor to Saint John's University and Saint John's Abbey, in north-central Minnesota, sees something of Gothic heritage while standing in front of the abbey church, designed and built around 1960. The church's 112-foot campanile--a trapezoidal slab made of 2,500 tons of steel and concrete--stands boldly in front of a huge concrete honeycomb…

  14. John Bartlett and bioterrorism.

    PubMed

    Henderson, D A

    2014-09-15

    Until 1997, the subject of bioterrorism was not discussed within the medical community and deliberately ignored in national planning efforts. Biological weapons were regarded as "morally repulsive." This complacency stemmed from a 1972 Biological Weapons Convention where all countries agreed to cease offensive biological weapons research. In the 1990s, however, the Soviet Union was discovered to have an extensive bioweapons program and a Japanese religious cult sought to launch an anthrax attack on Tokyo. Biological weapons such as smallpox and anthrax had the potential to cause a national catastrophe. However, little was done until John Bartlett in 1997 led a symposium and program to educate the medical community and the country of the need for definitive bioweapons programs. It was highly persuasive and received a final stimulus when the anthrax attack occurred in the United States in 2001. PMID:25151482

  15. JOHN MUIR WILDERNESS, CALIFORNIA.

    USGS Publications Warehouse

    Dellinger, David A.; Johnson, Frederick L.

    1984-01-01

    The mineral survey of the John Muir Wilderness, California revealed eight areas of probable and substantiated potential for the occurrence of mineral resources. Tungsten, with accompanying resources of gold, copper, silver, and molybdenum, is found along contacts between granitic rocks and metamorphosed calcareous sedimentary rocks; it is estimated that more than 1 million tons of demonstrated tungsten resources exist in areas of sustantiated resource potential within the wilderness. Resources of gold, silver, lead, copper, zinc, molydenum, and cobalt, occur in small deposits not associated with tungsten; however, the known deposits of these commodities are small and the possibility of the occurrence of larger ones is unlikely. The geologic setting precludes the presence of fossil fuel resources.

  16. Standing in the gap: ref lections on translating the Jung-Neumann correspondence.

    PubMed

    McCartney, Heather

    2016-04-01

    This paper considers the experience of translating the correspondence between C.G. Jung and Erich Neumann as part of the Philemon series. The translator explores the similarities between analytical work and the task of translation by means of the concepts of the dialectical third and the interactional field. The history and politics of the translation of analytic writing and their consequences for the lingua franca of analysis are discussed. Key themes within the correspondence are outlined, including Jung and Neumann's pre-war exploration of Judaism and the unconscious, the post-war difficulties around the publication of Neumann's Depth Psychology and a New Ethic set against the early years of the C.G. Jung Institute in Zurich, and the development of the correspondents' relationship over time. PMID:27000693

  17. Imposing Neumann boundary condition on cosmological perturbation equations and trajectories of particles

    NASA Astrophysics Data System (ADS)

    Shenavar, Hossein

    2016-03-01

    We impose Neumann boundary condition to solve cosmological perturbation equations and we derive a modified Friedmann equation and a new lensing equation. To check the new lensing equation and the value of Neumann constant, a sample that contains ten strong lensing systems is surveyed. Except for one lens, masses of the other lenses are found to be within the constrains of the observational data. Furthermore, we argue that by using the concept of geometrodynamic clocks it is possible to modify the equation of motion of massive particles too. Also, a sample that includes 101 HSB and LSB galaxies is used to re-estimate the value of the Neumann constant and we found that this value is consistent with the prior evaluation from Friedmann and lensing equations. Finally, the growth of structure is studied by a Newtonian approach which resulted in a more rapid rate of the structure formation in matter dominated era.

  18. Three-dimensional Neumann-series approach to model light transport in nonuniform media

    PubMed Central

    Jha, Abhinav K.; Kupinski, Matthew A.; Barrett, Harrison H.; Clarkson, Eric; Hartman, John H.

    2014-01-01

    We present the implementation, validation, and performance of a three-dimensional (3D) Neumann-series approach to model photon propagation in nonuniform media using the radiative transport equation (RTE). The RTE is implemented for nonuniform scattering media in a spherical harmonic basis for a diffuse-optical-imaging setup. The method is parallelizable and implemented on a computing system consisting of NVIDIA Tesla C2050 graphics processing units (GPUs). The GPU implementation provides a speedup of up to two orders of magnitude over non-GPU implementation, which leads to good computational efficiency for the Neumann-series method. The results using the method are compared with the results obtained using the Monte Carlo simulations for various small-geometry phantoms, and good agreement is observed. We observe that the Neumann-series approach gives accurate results in many cases where the diffusion approximation is not accurate. PMID:23201945

  19. Conjugate quasilinear Dirichlet and Neumann problems and a posteriori error bounds

    NASA Technical Reports Server (NTRS)

    Lavery, J. E.

    1976-01-01

    Quasilinear Dirichlet and Neumann problems on a rectangle D with boundary D prime are considered. Using these concepts, conjugate problems, that is, a pair of one Dirichlet and one Neumann problem, the minima of the energies of which add to zero, are introduced. From the concept of conjugate problems, two-sided bounds for the energy of the exact solution of any given Dirichlet or Neumann problem are constructed. These two-sided bounds for the energy at the exact solution are in turn used to obtain a posteriori error bounds for the norm of the difference of the approximate and exact solutions of the problem. These bounds do not involve the unknown exact solution and are easily constructed numerically.

  20. Simulating photon-transport in uniform media using the radiative transport equation: a study using the Neumann-series approach

    PubMed Central

    Jha, Abhinav K.; Kupinski, Matthew A.; Masumura, Takahiro; Clarkson, Eric; Maslov, Alexey V.; Barrett, Harrison H.

    2014-01-01

    We present the implementation, validation, and performance of a Neumann-series approach for simulating light propagation at optical wavelengths in uniform media using the radiative transport equation (RTE). The RTE is solved for an anisotropic-scattering medium in a spherical harmonic basis for a diffuse-optical-imaging setup. The main objectives of this paper are threefold: to present the theory behind the Neumann-series form for the RTE, to design and develop the mathematical methods and the software to implement the Neumann series for a diffuse-optical-imaging setup, and, finally, to perform an exhaustive study of the accuracy, practical limitations, and computational efficiency of the Neumann-series method. Through our results, we demonstrate that the Neumann-series approach can be used to model light propagation in uniform media with small geometries at optical wavelengths. PMID:23201893

  1. Pope John XXI, ophthalmologist.

    PubMed

    Blanchard, D

    1995-01-01

    Pope John XXI was an ophthalmologist before becoming Pope. He was born in Lisbon and trained at University of Paris and was part of the early medical school faculty in Siena. He became physician for Pope Gregory X and shifted to church duties. He rose quickly in the ranks of the Catholic church and was elected Pope in 1276 AD. His term was short. He died when construction in the Papal Palace at Viterbo, collapsed on him. His text book is in two parts with introductions to the eye followed by descriptions of diseases with their mostly medical treatments. He concludes with a section about his own wonderful waters. The work survived and a copy was even found amongst Michelangelo's papers. Unfortunately the book turns out to be a plagiarism of two earlier text books. His most notable achievement supposedly was discovering that glaucoma was a disease with a hard eye. It turns out that this section is referring only to a suppurative external disease with indurated lids called sclerophthalmia. PMID:7555583

  2. Searching for John Goodricke

    NASA Astrophysics Data System (ADS)

    French, Linda M.

    2010-01-01

    John Goodricke (1764-1786) is one of the most intriguing and enigmatic figures in the history of astronomy. Deaf from the age of five, his observations of the light variation of Algol brought him acclaim and the Copley Medal of the Royal Society by the age of nineteen. Together with his neighbor, mentor, and distant relative Edward Pigott, he went on to discover and quantify the light variations of other stars, including Delta Cephei. Goodricke's careful accounts of his observations, and their accuracy, remain a model of clear scientific thinking and reporting. Goodricke's career was short, as was his time on Earth: he died before his 22nd birthday. He left few personal notes or letters, and even many basic circumstances of his life have been misunderstood or misinterpreted. I will discuss Goodricke's apparent change of mind regarding the variations of Algol. I will further describe recent research into his family circumstances and into the allegation advanced by Zdenek Kopal in the 1980s that Goodricke was buried apart from his family because they were ashamed of his deafness.

  3. John Herschel's Graphical Method

    NASA Astrophysics Data System (ADS)

    Hankins, Thomas L.

    2011-01-01

    In 1833 John Herschel published an account of his graphical method for determining the orbits of double stars. He had hoped to be the first to determine such orbits, but Felix Savary in France and Johann Franz Encke in Germany beat him to the punch using analytical methods. Herschel was convinced, however, that his graphical method was much superior to analytical methods, because it used the judgment of the hand and eye to correct the inevitable errors of observation. Line graphs of the kind used by Herschel became common only in the 1830s, so Herschel was introducing a new method. He also found computation fatiguing and devised a "wheeled machine" to help him out. Encke was skeptical of Herschel's methods. He said that he lived for calculation and that the English would be better astronomers if they calculated more. It is difficult to believe that the entire Scientific Revolution of the 17th century took place without graphs and that only a few examples appeared in the 18th century. Herschel promoted the use of graphs, not only in astronomy, but also in the study of meteorology and terrestrial magnetism. Because he was the most prominent scientist in England, Herschel's advocacy greatly advanced graphical methods.

  4. The challenges of editorship: a reflection on editing the Jung-Neumann correspondence.

    PubMed

    Liebscher, Martin

    2016-04-01

    The complete correspondence between C.G. Jung and Erich Neumann was published in 2015. This article attempts to provide insight into the practical task, as well as the theoretical background, of the editing process. The advantages and possibilities of an unabridged edition with an extensive historical contextualization are demonstrated, and compared to the approach of the editors of the Jung Letters and their selection therein of Jung's letters to Neumann. The practical points under consideration include the establishment of the letter corpus, the ascertainment of dates and the chronological arrangement of the letter exchange, as well as the deciphering of handwritten letters. Theoretical aspects under discussion involve the question of the merits of a critical contextualisation and the position of the editor vis-à-vis the research object. The example of the selecting and editing of Jung's letters to Neumann by Aniela Jaffé and Gerhard Adler reveals how drastically the close ties of those editors with Jung, Neumann, and members of the Zurich analytical circles compromised their editorial work at times. The advantage for an editor being able to work from an historical distance is appreciated. PMID:27000692

  5. On stability of difference schemes for hyperbolic multipoint NBVP with Neumann conditions

    NASA Astrophysics Data System (ADS)

    Yildirim, Ozgur; Uzun, Meltem

    2016-08-01

    In this work, a multipoint nonlocal boundary value problem (NBVP) for hyperbolic equations with Neumann conditions is considered. Third and fourth order of accuracy stable difference schemes for solving this problem are presented. Efficiency of these schemes are tested via MATLAB implementation.

  6. Paulo Freire and the Politics of Education: A Response to Neumann

    ERIC Educational Resources Information Center

    Roberts, Peter

    2016-01-01

    Jacob Neumann provides a thoughtful reading of "Paulo Freire in the 21st century: Education, dialogue, and transformation" [v48 n6 p634-644 2016]. His comments on the importance of contextualising Freire's work and the value of openness in engaging Freirean ideas are insightful and helpful. His use of the term "apolitical" is,…

  7. My working week: John Innes.

    PubMed

    Innes, John

    2016-07-23

    In the first of a new series of features for Vet Record Careers, John Innes describes a recent working week as referrals director for CVS and a RCVS specialist in small animal orthopaedics. PMID:27450857

  8. An Interview with John Wilson.

    ERIC Educational Resources Information Center

    Halstead, J. Mark; McLaughlin, Terence H.

    2000-01-01

    Presents an interview with John Wilson covering topics such as: addressing the people who influenced him, highlighting Wilson's career and home background, and providing discussions on his opinions related to religion, morality, moral education, and the concept of authority. (CMK)

  9. Magic moments with John Bell

    SciTech Connect

    Bertlmann, Reinhold A.

    2015-07-15

    John Bell, with whom I had a fruitful collaboration and warm friendship, is best known for his seminal work on the foundations of quantum physics, but he also made outstanding contributions to particle physics and accelerator physics.

  10. John Glenn Entering Friendship 7

    NASA Technical Reports Server (NTRS)

    1962-01-01

    Overall view of astronaut John Glenn, Jr., as he enters into the spacecraft Friendship 7 prior to MA-6 launch operations at Launch Complex 14. Astronaut Glenn is entering his spacecraft to begin the first American manned Earth orbital mission.

  11. John Locke on Personal Identity**

    PubMed Central

    Nimbalkar, Namita

    2011-01-01

    John Locke speaks of personal identity and survival of consciousness after death. A criterion of personal identity through time is given. Such a criterion specifies, insofar as that is possible, the necessary and sufficient conditions for the survival of persons. John Locke holds that personal identity is a matter of psychological continuity. He considered personal identity (or the self) to be founded on consciousness (viz. memory), and not on the substance of either the soul or the body. PMID:21694978

  12. John locke on personal identity.

    PubMed

    Nimbalkar, Namita

    2011-01-01

    John Locke speaks of personal identity and survival of consciousness after death. A criterion of personal identity through time is given. Such a criterion specifies, insofar as that is possible, the necessary and sufficient conditions for the survival of persons. John Locke holds that personal identity is a matter of psychological continuity. He considered personal identity (or the self) to be founded on consciousness (viz. memory), and not on the substance of either the soul or the body. PMID:21694978

  13. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Dr. Wernher Von Braun (left) and Fred W. Kelley examine a ST-100 Stellar Instrument Platform in the astrionics lab. Dr. Von Braun, then deputy associate administrator for planning, NASA, was visiting on the anniversary of the establishment of the Marshall Space Flight Center.

  14. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1968-01-01

    Dr. Wernher Von Braun, stands in front of a Saturn IB Launch Vehicle at Kennedy Space Center (KSC). Dr. Von Braun was Marshall's first Center Director (1960-1970). Under his leadership Marshall was responsible for the development of the Saturn rockets, the Skylab project and getting the United States into Space and landing on the moon with the Apollo missions.

  15. Dr. Wernher von Braun

    NASA Technical Reports Server (NTRS)

    2004-01-01

    Dr. von Braun is looking out from a 10th floor window of building 4200 at the Marshall Space Flight Center (MSFC). He was the first Center Director and served as the Director from July 1960 through February 1970. Following World War II, Dr. von Braun and his German colleagues arrived in the United States under the Project Paperclip (American acquisition of German rocket experts) to continue their rocket development work. In 1950, von Braun and his German Rocket Team (also called the Peenemuende Team) were transferred from Ft. Bliss, Texas to Huntsville, Alabama to work for the Army's rocket program at Redstone Arsenal and later, NASA's Marshall Space Flight Center (MSFC). Under Dr. von Braun's leadership, MSFC developed the Saturn V launch vehicle, which placed the first men, two American astronauts, on the Moon. Wernher von Braun's life was dedicated to expanding man's knowledge through the exploration of space.

  16. Boundary integral equation Neumann-to-Dirichlet map method for gratings in conical diffraction.

    PubMed

    Wu, Yumao; Lu, Ya Yan

    2011-06-01

    Boundary integral equation methods for diffraction gratings are particularly suitable for gratings with complicated material interfaces but are difficult to implement due to the quasi-periodic Green's function and the singular integrals at the corners. In this paper, the boundary integral equation Neumann-to-Dirichlet map method for in-plane diffraction problems of gratings [Y. Wu and Y. Y. Lu, J. Opt. Soc. Am. A26, 2444 (2009)] is extended to conical diffraction problems. The method uses boundary integral equations to calculate the so-called Neumann-to-Dirichlet maps for homogeneous subdomains of the grating, so that the quasi-periodic Green's functions can be avoided. Since wave field components are coupled on material interfaces with the involvement of tangential derivatives, a least squares polynomial approximation technique is developed to evaluate tangential derivatives along these interfaces for conical diffraction problems. Numerical examples indicate that the method performs equally well for dielectric or metallic gratings. PMID:21643404

  17. A High-Order Direct Solver for Helmholtz Equations with Neumann Boundary Conditions

    NASA Technical Reports Server (NTRS)

    Sun, Xian-He; Zhuang, Yu

    1997-01-01

    In this study, a compact finite-difference discretization is first developed for Helmholtz equations on rectangular domains. Special treatments are then introduced for Neumann and Neumann-Dirichlet boundary conditions to achieve accuracy and separability. Finally, a Fast Fourier Transform (FFT) based technique is used to yield a fast direct solver. Analytical and experimental results show this newly proposed solver is comparable to the conventional second-order elliptic solver when accuracy is not a primary concern, and is significantly faster than that of the conventional solver if a highly accurate solution is required. In addition, this newly proposed fourth order Helmholtz solver is parallel in nature. It is readily available for parallel and distributed computers. The compact scheme introduced in this study is likely extendible for sixth-order accurate algorithms and for more general elliptic equations.

  18. Multi-grid solution of Neumann pressure problem for viscous flows using primitive variables

    NASA Technical Reports Server (NTRS)

    Ghia, U.; Ghia, K. N.; Ramamurti, R.

    1983-01-01

    The multi-grid (MG) technique has been advanced for use with the Neumann boundary-value problem in clustered curvilinear orthogonal coordinates. This comprises an important step in the analysis of viscous flows using the velocity-pressure formulation of the Navier-Stokes equations. With successive over-relaxation (SOR) as the smoothing operator and with suitably formulated restriction and coarse-grid-correction operators, a 4-grid procedure enhances the efficiency of fine-grid solutions of the Neumann problem by a factor of 3 to 5, depending on the problem parameters. Thy influence of the smoothing operator is also examined by employing the alternating-direction implicit and the strongly implicit techniques instead of SOR.

  19. Foreword: Sir John Pendry FRS Sir John Pendry FRS

    NASA Astrophysics Data System (ADS)

    Inglesfield, John; Echenique, Pedro

    2008-07-01

    John Pendry John Inglesfield and Pedro Echenique write: John Pendry's 65th birthday is on 4 July 2008, and this issue of the Journal of Physics: Condensed Matter is dedicated to him, with articles by friends, colleagues, and former students. By any standards, John Pendry is a great scientist, who has made—and continues to make—an enormous contribution to physics; the wide range of his interests is reflected in the scope of these articles. Not many scientists can establish a completely new and unexpected area of research, but this has been John's achievement in the last few years in the field of metamaterials, materials whose electromagnetic properties depend on their structure rather than the materials of which the structure is built. In this way, structures with effectively negative electrical permittivity and negative magnetic permeability can be constructed, demonstrating negative refraction; through metamaterials scientists now have access to properties not found in nature, and never previously explored experimentally. Never a week goes by without a potential new application of metamaterials, whether it is perfect lensing, or the cloak of invisibility. This has certainly led to tremendous visibility for John himself, with guest lectures all over the world, and radio and television appearances. John Pendry's first paper was published exactly 40 years ago, 'Analytic properties of pseudopotentials' [1], and since then he has published 310 articles at the latest count. But this first paper already reflected something of the way John works. His PhD project, with Volker Heine at the Cavendish Laboratory, was to interpret the scattering of low energy electrons from surfaces, the technique of LEED which was to become the method of choice for determining surface structure. Although the energy of the electrons in LEED is relatively low—say 50 eV—it is much higher than the energy of the conduction electrons, for which pseudopotentials had been devised, and John

  20. Spin chain from membrane and the Neumann-Rosochatius integrable system

    SciTech Connect

    Bozhilov, P.

    2007-11-15

    We find membrane configurations in AdS{sub 4}xS{sup 7}, which correspond to the continuous limit of the SU(2) integrable spin chain, considered as a limit of the SU(3) spin chain, arising in N=4 SYM in four dimensions, dual to strings in AdS{sub 5}xS{sup 5}. We also discuss the relationship with the Neumann-Rosochatius integrable system at the level of Lagrangians, comparing the string and membrane cases.

  1. Stability estimate for the aligned magnetic field in a periodic quantum waveguide from Dirichlet-to-Neumann map

    NASA Astrophysics Data System (ADS)

    Mejri, Youssef

    2016-06-01

    In this article, we study the boundary inverse problem of determining the aligned magnetic field appearing in the magnetic Schrödinger equation in a periodic quantum cylindrical waveguide, by knowledge of the Dirichlet-to-Neumann map. We prove a Hölder stability estimate with respect to the Dirichlet-to-Neumann map, by means of the geometrical optics solutions of the magnetic Schrödinger equation.

  2. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Dr. Wernher Von Braun (right), Deputy Associate Administrator for planning, National Aeronautics and Space Administration, inspects the mockup of the Saturn Workshop during a visit marking the 10th anniversary of the Marshall Center. Shown with Dr. Von Braun, from left to right, are Karl Heimburg, Director of the astronautics lab; Herman K. Weidner, Director of Science and Engineering, and George Hardy of the Astronautics lab.

  3. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Dr. Wernher Von Braun (right), Deputy Associate Administrator for Planning, National Aeronautics and Space Administration, inspects the mockup of the Saturn Workshop during a visit marking the 10th anniversary of the Marshall Center. Shown with Dr. Von Braun, from left to right, are Karl Heimburg, Director of the Astronautics Lab; Herman K. Weidner, Director of Science and Engineering, and George Hardy of the Astronautics Lab.

  4. Relation between the Negative-Order Harry Dym Hierarchy and a Family of Backward Neumann Type Systems

    NASA Astrophysics Data System (ADS)

    Chen, Jinbing

    2016-03-01

    From the bidirectional Lenard gradients, the negative-order Harry Dym (nHD) hierarchy is retrieved and further embedded into a bi-Hamiltonian structure displaying integrability. It follows from Neumann type integrable reduction that the nHD hierarchy is reduced to a family of backward Neumann type systems, which separate the temporal and spatial variables on the tangent bundle of an ellipsoid. Backward Neumann type systems are then proved to be completely integrable in the Liouville sense. From the commutativity of backward Neumann type flows, the relation between the nHD hierarchy and backward Neumann type systems is specified, where the involutive solutions of backward Neumann type systems yield the finite parametric solutions of the nHD hierarchy. Moreover, we propose the concept of a negative-order Novikov equation that cuts out a finite-dimensional invariant subspace for a negative-order integrable system, which paves an alternative way to obtain explicit solutions of negative-order integrable nonlinear evolution equations.

  5. The correspondence between Erich Neumann and C.G. Jung on the occasion of the November, progroms 1938 [corrected].

    PubMed

    Löwe, Angelica

    2015-06-01

    In the light of recently-published correspondence between Jung and Neumann, this paper considers and connects two aspects of their relationship: Jung's theory of an ethno-specific differentiation of the unconscious as formulated in 1934, and the relationship between Jung and Neumann at the beginning of the Holocaust in 1938-with Jung as the wise old man and a father figure on one hand, and Neumann as the apprentice and dependent son on the other. In examining these two issues, a detailed interpretation of four letters, two by Neumann and two by Jung, written in 1938 and 1939, is given. Neumann's reflections on the collective Jewish determination in the face of the November pogroms in 1938 led Jung to modify his view, with relativization and secularization of his former position. This shift precipitated a deep crisis with feelings of disorientation and desertion in Neumann; the paper discusses how a negative father complex was then constellated and imaged in a dream. After years of silence, the two men were able to renew the deep bonds that characterized their lifelong friendship. PMID:25989328

  6. John Wilson as Moral Educator

    ERIC Educational Resources Information Center

    Harrison, John L.

    1977-01-01

    The work of John Wilson, now teaching at Oxford University, as moral educator is summarized and evaluated. His rationalist humanistic approach is based on a componential characterization of the morally educated person. The rationale and conceptual status of the components is discussed. His position is compared to that of Peter McPhail, R. S.…

  7. John Wilson on Moral Education.

    ERIC Educational Resources Information Center

    McLaughlin, Terence H.; Halstead, J. Mark

    2000-01-01

    Describes the approach to moral education utilized by John Wilson focusing on his claims, arguments, and conclusions. Explores eight specific topics, such as his general perspective on moral education and the meaning and nature of moral. Reports on the areas of difficulty and criticism in relation to his approach. (CMK)

  8. The Johns Hopkins Hospital Network

    PubMed Central

    Tolchin, Stephen G.; Barta, Wendy; Harkness, Kenneth

    1985-01-01

    The Johns Hopkins Hospital has initiated an ambitious program to apply modern technologies to the development of a new, comprehensive clinical information system. One component of this system is a networking technology for supporting the integration of diverse and functionally distinct information systems. This paper discusses the selection of the networking technology implemented at JHH, issues and problems, networking concepts, protocols and reliability.

  9. John Milton: A Research Guide.

    ERIC Educational Resources Information Center

    Van Noate, Judith, Comp.

    This handout is a guide to library resources in the J. Murrey Atkins Library at the University of North Carolina-Charlotte, for sources of criticism for the study of 17th-century British author John Milton. The guide is intended to help readers find critical and biographical information on Milton. It explains important reference sources in the…

  10. Interview with John Taylor Gatto.

    ERIC Educational Resources Information Center

    Becker, Ellen

    1994-01-01

    Introduces ex-teacher and author John Taylor Gatto's experiences and views on education, including contradictory patterns of family life and education in the United States, based on traditions of various immigrant groups; deleterious impacts of standardization and institutional usurpation of family functions; and conflict between the development…

  11. John Rawls and Affirmative Action.

    ERIC Educational Resources Information Center

    Nagel, Thomas

    2003-01-01

    Discusses the philosophy of John Rawls, asserting that although Rawls never wrote about affirmative action, his ideas are relevant to the issue. Rawls concentrated on "ideal theory," which he believed was the theory of what constituted a truly just society. He considered slavery and racial segregation paradigms of injustice. His ideal theory of…

  12. John Dewey, Gothic and Modern

    ERIC Educational Resources Information Center

    Kaminsky, James S.

    2010-01-01

    It is argued here that understanding John Dewey's thought as that of a prodigal liberal or a fellow traveller does not capture the complexity of his work. It is also important to recognise the portion of his work that is "historie morale." In the very best sense it is epic, encapsulating the hopes and dreams of a history of the American people in…

  13. John Eliot in Recent Scholarship.

    ERIC Educational Resources Information Center

    Cogley, Richard W.

    1990-01-01

    Reviews the recent literature on John Eliot--seventeenth-century Massachusetts missionary, minister, and millenarian. Examines disagreements between Alden Vaughan's and Francis Jennings's interpretations of Eliot's missionary writings and Puritan-Indian relations. Discusses James Axtell's ethnohistorical interpretation of Eliot. Emphasizes the…

  14. The Art of John Biggers

    ERIC Educational Resources Information Center

    Coy, Mary

    2010-01-01

    In their 2005 exhibit of John Biggers' work, the New Orleans Museum of Art described it as being inspired by "African art and culture, the injustices of a segregated United States, the stoic women in his own family, and the heroes of everyday survival." In this article, the author describes how her students reinterpreted Biggers' work. (Contains 1…

  15. John Milton Oskison and Assimilation

    ERIC Educational Resources Information Center

    Larre, Lionel

    2013-01-01

    John Milton Oskison (1874-1947) was a Cherokee writer, journalist, and activist and the author of novels and biographies as well as numerous short stories, essays, and articles about a great variety of subjects. Oskison thought of himself as "an interpreter to the world, of the modern, progressive Indian." The kind of representation Oskison gave…

  16. Symposium: John Dewey: Patron Saint?

    ERIC Educational Resources Information Center

    New York University Education Quarterly, 1979

    1979-01-01

    James E. Wheeler, Mortimer Smith, Walter Feinberg, and Christiana M. Smith comment on the work of John Dewey and its relevance to modern educators. They respectively judge Dewey as significant and enduring, anti-intellectual, biased, and ambiguous. (Editor/SJL)

  17. John Couch Adams, the astronomer.

    NASA Astrophysics Data System (ADS)

    Foster, N.

    1989-03-01

    The planet Neptune was discovered more than 140 years ago. The circumstances of the discovery gave rise to great controversy, and very nearly led to an international incident between Britain and France, but this was only one of John Couch Adams' many contributions to astronomical science.

  18. John Milton's Rainbow: Sonnet XIX.

    ERIC Educational Resources Information Center

    Scher, Amy

    John Milton presented a wide spectrum of materials and ideas illuminating the literary landscape like a rainbow which critics and authors have been discussing for centuries. One example of the multiple layers of meaning in Milton's poems is found in Sonnet XIX, which can be useful for both forensic discussion as well as for composition…

  19. John James Audubon & the Turkey

    ERIC Educational Resources Information Center

    Hinshaw, Craig

    2012-01-01

    In the first half of the 1800s, John James Audubon roamed the wilds of America attempting to draw all the birds in their natural habitat. He published his life-sized paintings in a huge book entitled "Birds of America." Audubon developed a unique system of depicting the birds in natural poses, such as flying. After shooting the bird, he would wire…

  20. John N Bahcall (1934 2005)

    NASA Astrophysics Data System (ADS)

    Bergström, Lars; Botner, Olga; Carlson, Per; Hulth, Per Olof; Ohlsson, Tommy

    2005-01-01

    John Norris Bahcall, passed away on August 17, 2005, in NewYork City, USA. He was born on December 30, 1934, in Shreveport, Louisiana, USA. He was Richard Black Professor of Astrophysics in the School of Natural Sciences at the Institute forAdvanced Study (IAS) in Princeton, New Jersey, USA and a recipient of the National Medal of Science. In addition, he was President of the American Astronomical Society, President-Elect of the American Physical Society, and a prominent leader of the astrophysics community. John had a long and prolific career in astronomy and astrophysics, spanning five decades and the publication of more than five hundred technical articles, books, and popular papers. John's most recognized scientific contribution was the novel proposal in 1964, together with Raymond Davis Jr, that scientific mysteries of our Sun `how it shines, how old it is, how hot it is' could be examined by measuring the number of neutrinos arriving on Earth from the Sun. Measuring the properties of these neutrinos tests both our understanding of how stars shine and our understanding of fundamental particle physics. However, in the 1960s and 1970s, the observations by Raymond Davis Jr showed a clear discrepancy between John's theoretical predictions, based on standard solar and particle physics models, and what was experimentally measured. This discrepancy, known as the `Solar Neutrino Problem', was examined by hundreds of physicists, chemists, and astronomers over the subsequent three decades. In the late 1990s through 2002, new large-scale neutrino experiments in Japan, Canada, Italy, and Russia culminated in the conclusion that the discrepancy between John's theoretical predictions and the experimental results required a modification of our understanding of particle physics: neutrinos must have a mass and `oscillate' among different particle states. In addition to neutrino astrophysics, John contributed to many areas of astrophysics including the study of dark matter in

  1. John Glenn: Chosen To Cross The Threshold

    NASA Technical Reports Server (NTRS)

    1963-01-01

    John Glenn in training. From film to tape transfer of the film 'Friendship 7 - John Glenn' Depicts the historical orbital flight of John Glenn aboard 'Friendship 7', launched on February 20, 1962. Footage of staff at tracking stations worldwide and at Goddard Space Flight Center. Launch from cape canaveral. Flight tracking, re-entry, landing and recovery of Friendship 7.

  2. Foreword: Sir John Pendry FRS Sir John Pendry FRS

    NASA Astrophysics Data System (ADS)

    Inglesfield, John; Echenique, Pedro

    2008-07-01

    John Pendry John Inglesfield and Pedro Echenique write: John Pendry's 65th birthday is on 4 July 2008, and this issue of the Journal of Physics: Condensed Matter is dedicated to him, with articles by friends, colleagues, and former students. By any standards, John Pendry is a great scientist, who has made—and continues to make—an enormous contribution to physics; the wide range of his interests is reflected in the scope of these articles. Not many scientists can establish a completely new and unexpected area of research, but this has been John's achievement in the last few years in the field of metamaterials, materials whose electromagnetic properties depend on their structure rather than the materials of which the structure is built. In this way, structures with effectively negative electrical permittivity and negative magnetic permeability can be constructed, demonstrating negative refraction; through metamaterials scientists now have access to properties not found in nature, and never previously explored experimentally. Never a week goes by without a potential new application of metamaterials, whether it is perfect lensing, or the cloak of invisibility. This has certainly led to tremendous visibility for John himself, with guest lectures all over the world, and radio and television appearances. John Pendry's first paper was published exactly 40 years ago, 'Analytic properties of pseudopotentials' [1], and since then he has published 310 articles at the latest count. But this first paper already reflected something of the way John works. His PhD project, with Volker Heine at the Cavendish Laboratory, was to interpret the scattering of low energy electrons from surfaces, the technique of LEED which was to become the method of choice for determining surface structure. Although the energy of the electrons in LEED is relatively low—say 50 eV—it is much higher than the energy of the conduction electrons, for which pseudopotentials had been devised, and John

  3. Welfare effects of reduced milk production associated with Johne's disease on Johne's-positive versus Johne's-negative dairy operations.

    PubMed

    Losinger, Willard C

    2006-08-01

    An examination of the economic impacts of reduced milk production associated with Johne's disease on Johne's-positive and Johne's-negative dairy operations indicated that, if Johne's disease had not existed in US dairy cows in 1996, then the economic surplus of Johne's-negative operations would have been $600 million+/-$530 million lower, while the economic surplus of Johne's-positive operations would have been higher by $28 million+/-$79 million, which was not significantly different from zero. The data available for projecting changes in surplus were not sufficiently precise to allow an exact statement on whether Johne's-positive operations would have been better or worse off economically, in terms of the value received for producing more milk if they had not been affected by Johne's disease. The changes in producer surplus, based upon eliminating specific epidemiological risk factors for Johne's disease, were disaggregated between Johne's-positive dairy operations exposed to the risk factor and all other US dairy operations. Eliminating the risk factor of having any cows not born on the operation would have had a significant positive effect on the economic surplus of Johne's-positive operations that had any cows not born on the operation. PMID:16827950

  4. John Glenn: Enters Friendship 7 to Prepare for Launch

    NASA Technical Reports Server (NTRS)

    1963-01-01

    John glenn entering the capsule prior to the launch of Friendship 7 From: The John Glenn Story: Summary of astronaut John Glenn's flying career, from naval aviation training to space flight. The Mercury project is featured as John Glenn flies the Friendship 7 spacecraft. President John F. Kennedy presents the NASA Distinguished service Medal to Astronaut John Glenn.

  5. John Glenn: Post-Flight Recovery of Friendship 7

    NASA Technical Reports Server (NTRS)

    1963-01-01

    Mini Biography of John Glenn, as it was up to 1962. From: The John Glenn Story: Summary of astronaut John Glenn's flying career, from naval aviation training to space flight. The Mercury project is featured as John Glenn flies the Friendship 7 spacecraft. President John F. Kennedy presents the NASA Distinguished service Medal to Astronaut John Glenn.

  6. John Glenn: Presented with NASA Distinguished Service Medal

    NASA Technical Reports Server (NTRS)

    1963-01-01

    John Glenn tours with his family, meets JFK and is presented with the NASA distinguished Service Medal. From: The John Glenn Story: Summary of astronaut John Glenn's flying career, from naval aviation training to space flight. The Mercury project is featured as John Glenn flies the Friendship 7 spacecraft. President John F. Kennedy presents the NASA Distinguished service Medal to Astronaut John Glenn.

  7. The letters of John Dastin.

    PubMed

    Thiesen, Wilfred

    2008-07-01

    John Dastin, a noted alchemist who lived ca. 1300, followed the lead of many of his contemporaries and predecessors in using letters to propagate his views on alchemy. This article identifies a number of letters that Dastin wrote, and includes one text addressed to a cardinal of the city of Naples. This letter is virtually a copy of a work by Arnold of Villanova. I believe that other works ascribed to Dastin will also show a great dependence on Arnold's works. PMID:19048973

  8. Charles Darwin and John Herschel

    NASA Astrophysics Data System (ADS)

    Warner, B.

    2009-11-01

    The influence of John Herschel on the philosophical thoughts of Charles Darwin, both through the former's book, Natural Philosophy, and through their meeting in 1836 at the Cape of Good Hope, is discussed. With Herschel having himself speculated on evolution just a few months before he met Darwin, it is probable that he stimulated at least the beginnings of the latter's lifelong work on the subject.

  9. John Glenn Biomedical Engineering Consortium

    NASA Technical Reports Server (NTRS)

    Nall, Marsha

    2004-01-01

    The John Glenn Biomedical Engineering Consortium is an inter-institutional research and technology development, beginning with ten projects in FY02 that are aimed at applying GRC expertise in fluid physics and sensor development with local biomedical expertise to mitigate the risks of space flight on the health, safety, and performance of astronauts. It is anticipated that several new technologies will be developed that are applicable to both medical needs in space and on earth.

  10. Von Willebrand factor and von Willebrand disease.

    PubMed

    Budde, U; Schneppenheim, R

    2001-12-01

    von Willebrand disease (vWD) is caused by quantitative and/or qualitative defects of the von Willebrand factor (vWF), a multimeric high molecular weight glycoprotein. Typically, it affects the primary hemostatic system, which results in a mucocutaneous bleeding tendency simulating a platelet function defect. The vWF promotes its function in two ways: (i) by initiating platelet adhesion to the injured vessel wall under conditions of high shear forces, and (ii) by its carrier function for factor VIII in plasma. Accumulating knowledge of the different clinical phenotypes and the pathophysiological basis of the disease translated into a classification that differentiated between quantitative and qualitative defects by means of quantitative and functional parameters, and by analyzing the electrophoretic pattern of vWF multimers. The advent of molecular techniques provided the opportunity for conducting genotype-phenotype studies which have recently helped, not only to elucidate or confirm important functions of vWF and its steps in post-translational processing, but also many disease causing defects. Acquired von Willebrand syndrome (avWS) has gained more attention during the recent years. An international registry was published and recommendation by the Scientific and Standardization Committee of the International Society on Thrombosis and Haemostasis in 2000. It concluded that avWS, although not a frequent disease, is nevertheless probably underdiagnosed. This should be addressed in future prospective studies. The aim of treatment is the correction of the impaired hemostatic system of the patient, ideally including the defects of both primary and secondary hemostasis. Desmopressin is the treatment of choice in about 70% of patients, mostly with type 1, while the others merit treatment with concentrates containing vWF. PMID:11844133

  11. Transient spatio-temporal dynamics of a diffusive plant-herbivore system with Neumann boundary conditions.

    PubMed

    Yu, Fang; Wang, Lin; Watmough, James

    2016-12-01

    In many existing predator-prey or plant-herbivore models, the numerical response is assumed to be proportional to the functional response. In this paper, without such an assumption, we consider a diffusive plant-herbivore system with Neumann boundary conditions. Besides stability of spatially homogeneous steady states, we also derive conditions for the occurrence of Hopf bifurcation and steady-state bifurcation and provide geometrical methods to locate the bifurcation values. We numerically explore the complex transient spatio-temporal behaviours induced by these bifurcations. A large variety of different types of transient behaviours including oscillations in one or both of space and time are observed. PMID:27572052

  12. A forced fractional Schrödinger equation with a Neumann boundary condition

    NASA Astrophysics Data System (ADS)

    Esquivel, L.; Kaikina, Elena I.

    2016-07-01

    We study the initial-boundary value problem for the nonlinear fractional Schrödinger equation {ut+i(uxx+12π∫0∞sign(x‑y)|x‑y|12uy( y)dy)+i|u|2u=0, t>0, x>0u(x,0)=u0(x), x>0,ux(0,t)=h(t), t>0. We prove the global-in-time existence of solutions for a nonlinear fractional Schrödinger equation with inhomogeneous Neumann boundary conditions. We are also interested in the study of the asymptotic behaviour of the solutions.

  13. [Acquired von Willebrand syndrome].

    PubMed

    Franchini, Massimo

    2006-01-01

    Acquired von Willebrand syndrome (aVWS) is a rare, but probably underestimated, bleeding disorder that mimics the congenital form of von Willebrand disease (VWD) in terms of laboratory findings and clinical presentation. However, unlike congenital VWD, it arises in individuals with no personal or family history of bleeding. AVWS occurs in association with a variety of underlying disorders, including lymphoproliferative disorders, myeloproliferative disorders and cardiovascular diseases. The main pathogenic, clinical, laboratory and therapeutic aspects of this syndrome are concisely reported in this review. PMID:16913181

  14. Neumann type integrable reduction for nonlinear evolution equations in 1+1 and 2+1 dimensions

    NASA Astrophysics Data System (ADS)

    Chen, Jinbing

    2009-12-01

    A family of new Neumann type systems is given in view of the nonlinearization technique, realizing the variable separation of the modified Jaulent-Miodek hierarchy and a new coupled modified Kadomtsev-Petviashvili equation on the symplectic submanifold TSN -1. By two Casimir functions and a special solution of the Lenard eigenvalue equation, we deduce the Lax-Moser matrix of the Neumann type systems that yields integrals of motion and the constrained Hamiltonians whose vector fields are tangent to TSN -1. Based on the Dirac-Poisson bracket and a Lax equation on TSN -1, a new systematic way is proposed to prove the Liouville integrability of a family of Neumann type systems synchronously. The Dirac-Poisson bracket and the generating function are used to reveal the explicit relation between infinite dimensional integrable systems and Neumann type systems, and then we point out that compatible solutions of Neumann type systems yield the finite parametric solutions of 1+1 and 2+1 dimensional integrable nonlinear evolution equations and the finite-gap solutions of the Novikov equation.

  15. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1999-01-01

    A camerman catches Dr. Wernher Von Braun, Director of the Marshall Space Flight Center, his son, Peter, and daughter, Martgrit, as they arrive at the employee picnic held to celebrate man's first landing on the moon 6 days earlier. In the foreground is David R. Newby, Director of Administration and Technical Services at the Marshall Space Flight Center.

  16. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Shown viewing the Apollo telescope mockup are, from left to right, Charles Donlan, deputy associate administrator for manned space flight; Dr. Wernher Von Braun, Marshall Space Flight Center director; William Horton, astrionics lab; Dr. Thomas Paine, NASA deputy administrator; Warner Kuers, director of the ME lab.

  17. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Marshall Space Flight Center director Wernher Von Braun and his family were honored with a series of events prior to his relocation to Washington, D.C. where he was assigned duties at NASA headquarters as deputy associate administrator for planning. Here he is shown with General Richard Drury and Hazel Toftoy, widow of General H.N. Toftoy.

  18. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1968-01-01

    Dr. Wernher von Braun, Director of the Marshall Space Flight Center, explains the purpose of a thermal curtain in the mockup of a Saturn I workshop to U.S. Representative Armistead Seldon of Alabama. The Congressman visited the Marshall Center on March 2, 1968 to tour the workshop and to visit Marshall Center facilities.

  19. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1968-01-01

    U.S. Representative Armistead Seldon (D.-Al) inspects the food preparation area of the Saturn I workshop mockup during a visit to the Marshall Space Flight Center. Explaining the operation of the food preparation area to the congressman is Dr. Wernher Von Braun, Marshall Space Flight Center director.

  20. Analytik von Lebensmittelallergenen

    NASA Astrophysics Data System (ADS)

    Demmel, Anja; Hahn, Alexandra

    Ansonsten harmlose Lebensmittel oder deren Bestandteile können bei von Lebensmittelallergien betroffenen Personen Überempfindlichkeitsreaktionen auslösen. Hierbei kann es sich um immunvermittelte Lebensmittelallergien oder um Intoleranzen gegenüber bestimmten Lebensmittelbestandteilen handeln. Ein Beispiel für Letzteres ist die Laktoseintoleranz, welche durch einen Enzymdefekt hervorgerufen wird [1]. Im Gegensatz hierzu handelt es sich bei Lebensmittelallergien um Sofortreaktionen, die durch IgE-Antikörper gegen Antigene aus den Lebensmitteln hervorgerufen werden und zu verschiedenen körperlichen Beschwerden führen können. Bei den Antigenen, welche von den von Allergikern produzierten IgE-Antikörpern erkannt werden, handelt es sich vor allem um Proteine [2]. Symptome IgE-vermittelter Reaktionen können zum Beispiel Hautausschlag, eine Schwellung der Schleimhäute oder das sogenannte orale Allergiesyndrom mit allergischen Reaktionen an der Mundschleimhaut und im Magen-Darm-Trakt sein [3]. Die hierbei auftretenden Beschwerden reichen von einem Brennen im Mund und einer Schwellung der Lippen und der Zunge bis zu Atemnot verursachenden Schwellungen im Kehlkopfbereich. In besonders schlimmen Fällen können allergische Reaktionen zu einem anaphylaktischen Schock und zum Tod durch Kreislaufversagen führen [4]. Während klassische Nahrungsallergene häufig komplexe Reaktionen zur Folge haben, ist bei Pollen-assoziierten Nahrungsmittelallergien das orale Allergiesyndrom vorherrschend.

  1. Acquired von Willebrand disease.

    PubMed

    Petrini, P

    1999-05-01

    Acquired von Willebrand disease (AvWD) is a syndrome that has clinical and laboratory features similar to hereditary vWD. In contrast to the latter it occurs in patients without a family history of previous bleeding tendency. PMID:23401904

  2. A novel hybrid Neumann expansion method for stochastic analysis of mistuned bladed discs

    NASA Astrophysics Data System (ADS)

    Yuan, Jie; Allegri, Giuliano; Scarpa, Fabrizio; Patsias, Sophoclis; Rajasekaran, Ramesh

    2016-05-01

    The paper presents a novel hybrid method to enhance the computational efficiency of matrix inversions during the stochastic analysis of mistuned bladed disc systems. The method is based on the use of stochastic Neumann expansion in the frequency domain, coupled with a matrix factorization in the neighbourhood of the resonant frequencies. The number of the expansion terms is used as an indicator to select the matrix inversion technique to be used, without introducing any additional computational cost. The proposed method is validated using two case studies, where the dynamics an aero-engine bladed disc is modelled first using a lumped parameter approach and then with high-fidelity finite element analysis. The frequency responses of the blades are evaluated according to different mistuning patterns via stiffness or mass perturbations under the excitation provided by the engine orders. Results from standard matrix factorization methods are used to benchmark the responses obtained from the proposed hybrid method. Unlike classic Neumann expansion methods, the new technique can effectively update the inversion of an uncertain matrix with no convergence problems during Monte Carlo simulations. The novel hybrid method is more computationally efficient than standard techniques, with no accuracy loss.

  3. John Dalton (1766-1844).

    PubMed Central

    Emery, A E

    1988-01-01

    There is no doubt that John Dalton ranks among the great names in science, a position which rests on his enunciation of the Atomic Theory. However, his very first scientific paper in 1798 was concerned with his own affliction of colour blindness and was in fact the first clear description of the disorder. This publication stimulated much subsequent research into the pathophysiology and genetics of the condition. His recorded observations on colour blindness are detailed and precise and betoken the approach which was to characterise all his later research in chemistry. Images PMID:3294412

  4. John Bardeen: an extraordinary physicist

    NASA Astrophysics Data System (ADS)

    Hoddeson, Lillian

    2008-04-01

    On the morning of 1 November 1956 the US physicist John Bardeen dropped the frying-pan of eggs that he was cooking for breakfast, scattering its contents on the kitchen floor. He had just heard that he had won the Nobel Prize for Physics along with William Shockley and Walter Brattain for their invention of the transistor. That evening Bardeen was startled again, this time by a parade of his colleagues from the University of Illinois marching to the door of his home bearing champagne and singing "For He's a Jolly Good Fellow".

  5. John Greenleaf's life of science.

    PubMed

    Watenpaugh, Donald E

    2012-12-01

    This article summarizes the life and career of John E. Greenleaf, PhD. It complements an interview of Dr. Greenleaf sponsored by the American Physiological Society Living History Project found on the American Physiological Society website. Dr. Greenleaf is a "thought leader" and internationally renowned physiologist, with extensive contributions in human systems-level environmental physiology. He avoided self-aggrandizement and believed that deeds rather than words define one's legacy. Viewed another way, however, Greenleaf's words define his deeds: 48% of his 185 articles are first author works, which is an unusually high proportion for a scientist of his stature. He found that writing a thorough and thoughtful discussion section often led to novel ideas that drove future research. Beyond Greenleaf's words are the many students, postdocs, and collaborators lucky enough to have worked with him and thus learn and carry on his ways of science. His core principles included the following: avoid research "fads," embrace diversity, be the first subject in your own research, adhere to rules of fiscal responsibility, and respect administrative forces-but never back down from them when you know you are right. Greenleaf's integrity ensured he was usually right. He thrived on the axiom of many successful scientists: avoid falling in love with hypotheses, so that when unexpected findings appear, they arouse curiosity instead of fear. Dr. Greenleaf's legacy will include the John and Carol Greenleaf Award for prolific environmental and exercise-related publication in the Journal of Applied Physiology. PMID:23209002

  6. John Bardeen and transistor physics

    NASA Astrophysics Data System (ADS)

    Huff, Howard R.

    2001-01-01

    John Bardeen and Walter Brattain invented the point-contact semiconductor amplifier (transistor action) in polycrystalline germanium (also observed in polycrystalline silicon) on Dec. 15, 1947, for which they received a patent on Oct. 3, 1950. Bill Shockley was not a co-patent holder on Bardeen and Brattain's point-contact semiconductor amplifier patent since Julius Lilienfeld had already received a patent in 1930 for what would have been Shockley's contribution; namely, the field-effect methodology. Shockley received patents for both his minority-carrier injection concept and junction transistor theory, however, and deservedly shared the Nobel prize with Bardeen and Brattain for his seminal contributions of injection, p-n junction theory and junction transistor theory. We will review the events leading up to the invention of Bardeen and Brattain's point-contact semiconductor amplifier during the magic month of November 17-December 16, 1947 and the invention of Shockley's junction semiconductor amplifier during his magic month of December 24, 1947-January 23, 1948. It was during the course of Bardeen and Brattain's research in November, 1947 that Bardeen also patented the essence of the MOS transistor, wherein the induced minority carriers were confined to the inversion layer enroute to the collector. C. T. Sah has described this device as a sourceless MOS transistor. Indeed, John Bardeen, co-inventor of the point-contact semiconductor amplifier and inventor of the MOS transistor, may rightly be called the father of modern electronics.

  7. von Willebrand Disease

    PubMed Central

    Goodeve, Anne C.

    2013-01-01

    von Willebrand disease (VWD) is a common inherited bleeding disorder characterized by excessive mucocutaneous bleeding. Characteristic bleeding symptoms include epistaxis, easy bruising, oral cavity bleeding, menorrhagia, bleeding after dental extraction, surgery and/or childbirth and in severe cases, bleeding into joints and soft tissues. There are three subtypes: types 1 and 3 represent quantitative variants and type 2 is a group of four qualitative variants: 1) type 2A - characterized by defective von Willebrand factor (VWF) -dependent platelet adhesion because of decreased high molecular weight (HMW) VWF multimers, 2) type 2B - caused by pathologically increased VWF-platelet interactions, 3) type 2M - caused by decreased VWF-platelet interactions not based on the loss of HMW multimers and 4) type 2N - characterized by abnormal binding of VWF to FVIII. The diagnosis of VWD requires specialized assays of von Willebrand factor (VWF) and/or molecular genetic testing of VWF. Severe bleeding episodes can be prevented or controlled with intravenous infusions of virally-inactivated plasma-derived clotting factor concentrates containing both VWF and FVIII. Depending on the VWD type, mild bleeding episodes usually respond to intravenous or subcutaneous treatment with desmopressin, a vasopressin analog. Other treatments that can reduce symptoms include fibrinolytic inhibitors and hormones for menorrhagia. PMID:21289515

  8. Neumann and Robin boundary conditions for heat conduction modeling using smoothed particle hydrodynamics

    NASA Astrophysics Data System (ADS)

    Esmaili Sikarudi, M. A.; Nikseresht, A. H.

    2016-01-01

    Smoothed particle hydrodynamics is a robust Lagrangian particle method which is widely used in various applications, from astrophysics to hydrodynamics and heat conduction. It has intrinsic capabilities for simulating large deformation, composites, multiphysics events, and multiphase fluid flows. It is vital to use reliable boundary conditions when boundary value problems like heat conduction or Poisson equation for incompressible flows are solved. Since smoothed particle hydrodynamics is not a boundary fitted grids method, implementation of boundary conditions can be problematic. Many methods have been proposed for enhancing the accuracy of implementation of boundary conditions. In the present study a new approach for facilitating the implementation of Robin and Neumann boundary conditions is proposed and proven to give accurate results. Also there is no need to use complicated preprocessing as in virtual particle method. The new method is compared to an equivalent one dimensional moving least square scheme and it is shown that the present method is less sensitive to particle disorder.

  9. Computing Photonic Crystal Defect Modes by Dirichlet-to-Neumann Maps.

    PubMed

    Li, Shaojie; Lu, Ya Yan

    2007-10-29

    We develop an efficient numerical method for computing defect modes in two dimensional photonic crystals based on the Dirichletto- Neumann (DtN) maps of the defect and normal unit cells. The DtN map of a unit cell is an operator that maps the wave field on the boundary of the cell to its normal derivative. The frequencies of the defect modes are solved from a condition that a small matrix is singular. The size of the matrix is related to the number of points used to discretize the boundary of the defect cell. The matrix is obtained by solving a linear system involving only discrete points on the edges of the unit cells in a truncated domain. PMID:19550723

  10. Modeling photonic crystals by boundary integral equations and Dirichlet-to-Neumann maps

    SciTech Connect

    Yuan Jianhua; Lu Yayan Antoine, Xavier

    2008-04-20

    Efficient numerical methods for analyzing photonic crystals (PhCs) can be developed using the Dirichlet-to-Neumann (DtN) maps of the unit cells. The DtN map is an operator that takes the wave field on the boundary of a unit cell to its normal derivative. In frequency domain calculations for band structures and transmission spectra of finite PhCs, the DtN maps allow us to reduce the computation to the boundaries of the unit cells. For two-dimensional (2D) PhCs with unit cells containing circular cylinders, the DtN maps can be constructed from analytic solutions (the cylindrical waves). In this paper, we develop a boundary integral equation method for computing DtN maps of general unit cells containing cylinders with arbitrary cross sections. The DtN map method is used to analyze band structures for 2D PhCs with elliptic and other cylinders.

  11. The KdV equation on the half-line: the Dirichlet to Neumann map

    NASA Astrophysics Data System (ADS)

    >Jonatan Lenells,

    2013-08-01

    We consider initial-boundary value problems for the KdV equation ut + ux + 6uux + uxxx = 0 on the half-line x ⩾ 0. For a well-posed problem, the initial data u(x, 0) as well as one of the three boundary values {u(0, t), ux(0, t), uxx(0, t)} can be prescribed; the other two boundary values remain unknown. We provide a characterization of the unknown boundary values for the Dirichlet as well as the two Neumann problems in terms of a system of nonlinear integral equations. The characterizations are effective in the sense that the integral equations can be solved perturbatively to all orders in a well-defined recursive scheme.

  12. 75 FR 49497 - John Bonnes: Debarment Order

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-13

    ... HUMAN SERVICES Food and Drug Administration John Bonnes: Debarment Order AGENCY: Food and Drug... the Federal Food, Drug, and Cosmetic Act (the act) debarring John Bonnes for a period of 5 years from... the act, under authority delegated to the Director (Staff Manual Guide 1410.35), finds that Mr....

  13. A to Z with Jasper Johns

    ERIC Educational Resources Information Center

    Kirker, Sara Schmickle

    2008-01-01

    One contemporary artist that kindergarten students can easily relate to is Jasper Johns. In this article, the author discusses how she introduced John's numeric and alphabetic paintings to her kindergarten students. The young artists were amazed that art can be created from the familiar symbols that they are learning to make in their regular…

  14. John Herschel and astronomy: a bicentennial appraisal.

    NASA Astrophysics Data System (ADS)

    Hoskin, M. A.

    An assessment is given of John Herschel's overall contributions to nineteenth century astronomy. John Herschel built on his pioneering father William Herschel's foundations, with revisions and extensions to the southern hemisphere. His work, incorporated into his general treatises on astronomy, had a major influence on the direction of astronomical progress.

  15. John Herschel: Britain's first modern physical scientist.

    NASA Astrophysics Data System (ADS)

    Crowe, M. J.

    The author presents a sketch of the life and contributions to science of Sir John F. W. Herschel (1792 - 1871). One of the theses he develops is that John Herschel can meaningfully be described as Britain's first modern physical scientist. In addition to developing this thesis, the author makes some remarks about lesser known aspects of Herschel's life.

  16. Symposium on John Dewey's "Art as Experience."

    ERIC Educational Resources Information Center

    Burnett, Joe R.; And Others

    1989-01-01

    Reports on a symposium about John Dewey's philosophy of art. John Fisher, Richard Shusterman, and Joe R. Burnett state their views on Dewey's contributions to art theory and aesthetics citing Dewey's work, "Art As Experience." The consensus was that although Dewey's opinions are dated, his pragmatist's views offer the opportunity for further study…

  17. Solving: The Case of John, Part I

    ERIC Educational Resources Information Center

    Drell, Martin J.; Josephson, Allan; Pleak, Richard; Riggs, Paula; Rosenfeld, Alvin

    2006-01-01

    In this article, one of the authors was called to see an 18-year old boy named John, who had done poorly during his first year at college and was depressed. His parents feared that their son may be suicidal, a concern heightened by the recent news that one of their son's friends had committed suicide. Here, he interviews John about his…

  18. John Henry--The Steel Driving Man

    ERIC Educational Resources Information Center

    Murphy, David E.; Gulley, Laura L.

    2005-01-01

    The story of John Henry provided the setting for sixth-grade class to participate in a John Henry Day of mathematics experiments. The students collected data from experiments where students competed against machines and technology. The student analyzed the data by comparing two box plots, a box plot of human data, and a box plot of machine or…

  19. John Kotter on Leadership, Management and Change.

    ERIC Educational Resources Information Center

    Bencivenga, Jim

    2002-01-01

    Excerpts from interview with John Kotter, Konosuke Matsushita Professor of Leadership at the Harvard Business School, about his thoughts on the role of the superintendent as leader and manager. Describes his recent book "John P. Kotter on What Leaders Really Do," 1999. Lists eight-step change process from his book "Leading Change," 1996. (PKP)

  20. Struggle for the Soul: John Lawrence Childs

    ERIC Educational Resources Information Center

    Stallones, Jared

    2010-01-01

    John Lawrence Childs was born in Eau Claire, Wisconsin on January 11, 1889, the second child of John Nelson Childs and Helen Janette (Nettie) Smith. In childhood Childs absorbed the values of industry, democracy, and a traditional, but socially conscious, religion. Childs was a Methodist and an intensely private person not given to talking about…

  1. John H. Reynolds (1923-2000)

    NASA Astrophysics Data System (ADS)

    Turner, Grenville

    John Reynolds, AGU Fellow since 1968 and a member of the Volcanology Geochemistry and Petrology section since 1961, died unexpectedly on November 4, 2000. John was a professor emeritus of physics at the University of California, Berkeley and a pioneer in the development and application of noble gas mass spectrometry He was recovering from pneumonia when he suffered a pulmonary embolism.

  2. One Measure Does Not a Construct Make: Directions toward Reinvigorating Psychopathy Research--Reply to Hare and Neumann (2010)

    ERIC Educational Resources Information Center

    Skeem, Jennifer L.; Cooke, David J.

    2010-01-01

    In our article (J. L. Skeem & D. J. Cooke, 2010), we outlined the dangers inherent in conflating the Psychopathy Checklist-Revised (PCL-R; R. Hare, 1991) with psychopathy itself. In their response, R. Hare and C. Neumann (2010) seemed to agree with key points that the PCL-R should not be confused with psychopathy and that criminal behavior is not…

  3. John Bahcall and the Solar Neutrino Problem

    NASA Astrophysics Data System (ADS)

    Bahcall, Neta

    2016-03-01

    ``I feel like dancing'', cheered John Bahcall upon hearing the exciting news from the SNO experiment in 2001. The results confirmed, with remarkable accuracy, John's 40-year effort to predict the rate of neutrinos from the Sun based on sophisticated Solar models. What began in 1962 by John Bahcall and Ray Davis as a pioneering project to test and confirm how the Sun shines, quickly turned into a four-decade-long mystery of the `Solar Neutrino Problem': John's models predicted a higher rate of neutrinos than detected by Davis and follow-up experiments. Was the theory of the Sun wrong? Were John's calculations in error? Were the neutrino experiments wrong? John worked tirelessly to understand the physics behind the Solar Neutrino Problem; he led the efforts to greatly increase the accurately of the solar model, to understand its seismology and neutrino fluxes, to use the neutrino fluxes as a test for new physics, and to advocate for important new experiments. It slowly became clear that none of the then discussed possibilities --- error in the Solar model or neutrino experiments --- was the culprit. The SNO results revealed that John's calculations, and hence the theory of the Solar model, have been correct all along. Comparison of the data with John's theory demanded new physics --- neutrino oscillations. The Solar Neutrino saga is one of the most amazing scientific stories of the century: exploring a simple question of `How the Sun Shines?' led to the discovery of new physics. John's theoretical calculations are an integral part of this journey; they provide the foundation for the Solar Neutrino Problem, for confirming how the Sun shines, and for the need of neutrino oscillations. His tenacious persistence, dedication, enthusiasm and love for the project, and his leadership and advocacy of neutrino physics over many decades are a remarkable story of scientific triumph. I know John is smiling today.

  4. Photocopy of photograph (from Mrs. Martin, grandniece of John French, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Photocopy of photograph (from Mrs. Martin, grandniece of John French, Clinton, Missouri) Circa 1900, photographer unknown JOHN AND ALMIRA FRENCH IN FRONT OF WEST AND SOUTH FACADES - John French Farm, South Grand River, Deepwater, Henry County, MO

  5. Finite-gap solutions of 2+1 dimensional integrable nonlinear evolution equations generated by the Neumann systems

    NASA Astrophysics Data System (ADS)

    Chen, Jinbing

    2010-08-01

    Each soliton equation in the Korteweg-de Vries (KdV) hierarchy, the 2+1 dimensional breaking soliton equation, and the 2+1 dimensional Caudrey-Dodd-Gibbon-Kotera-Sawada (CDGKS) equation are reduced to two or three Neumann systems on the tangent bundle TSN -1 of the unit sphere SN -1. The Lax-Moser matrix for the Neumann systems of degree N -1 is deduced in view of the Mckean-Trubowitz identity and a bilinear generating function, whose favorite characteristic accounts for the problem of the genus of Riemann surface matching to the number of elliptic variables. From the Lax-Moser matrix, the constrained Hamiltonians in the sense of Dirac-Poisson bracket for all the Neumann systems are written down in a uniform recursively determined by integrals of motion. The involution of integrals of motion and constrained Hamiltonians is completed on TSN -1 by using a Lax equation and their functional independence is displayed over a dense open subset of TSN -1 by a direct calculation, which contribute to the Liouville integrability of a family of Neumann systems in a new systematical way. We also construct the hyperelliptic curve of Riemann surface and the Abel map straightening out the restricted Neumann flows that naturally leads to the Jacobi inversion problem on the Jacobian with the aid of the holomorphic differentials, from which some finite-gap solutions expressed by Riemann theta functions for the 2+1 dimensional breaking soliton equation, the 2+1 dimensional CDGKS equation, the KdV, and the fifth-order KdV equations are presented by means of the Riemann theorem.

  6. An Alternative to Von Glasersfeld's Subjectivism in Science Education: Deweyan Social Constructivism

    NASA Astrophysics Data System (ADS)

    Garrison, Jim

    An influential view of constructivism in science and mathematics educational research and practice is that of Ernst von Glasersfeld. It is a peculiarly subjectivist form of constructivism that should not be attractive to science and mathematics educators concerned with retaining some sort of realism that leaves room for objectivity. The subjectivist constructivism of von Glasersfeld also becomes entangled in untenable mind/body and subject/object dualisms. Finally, these dualisms are unnecessary for social constructivism. I will provide one example of a social constructivist alternative to social constructivism, that of the pragmatic philosopher John Dewey. In presenting Dewey's position I will appeal to Ockham's razor, that is, the admonition not to multiply entities beyond necessity, to shave off the needless mentalistic and psychic entities that lead von Glasersfeld into his subjectivism and dualism.

  7. 9. Historic American Buildings Survey, John A. Bryan, Photographer July ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. Historic American Buildings Survey, John A. Bryan, Photographer July 9, 1952 SOUTHWEST PERSPECTIVE. - St. John's Episcopal Mission, Chapel & Rectory, Fort Bennett Vicinity, Green Grass, Dewey County, SD

  8. 1. Historic American Buildings Survey, John A. Bryan, Photographer July ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    1. Historic American Buildings Survey, John A. Bryan, Photographer July 9, 1952 SOUTHEAST PERSPECTIVE. - St. John's Episcopal Mission, Chapel & Rectory, Fort Bennett Vicinity, Green Grass, Dewey County, SD

  9. 11. Historic American Buildings Survey, John A. Bryan, Photographer July ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    11. Historic American Buildings Survey, John A. Bryan, Photographer July 9, 1952 CHAPEL INTERIOR. - St. John's Episcopal Mission, Chapel & Rectory, Fort Bennett Vicinity, Green Grass, Dewey County, SD

  10. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Dr. Thomas Paine, Deputy Administrator of the National Aeronautics and Space Administration, examines an ordinary man's shoe outfitted for use in the Saturn I workshop. Pictured from the left in the Saturn I workshop mockup are William Brooksbank, propulsion and vehicle engineering laboratory; Dr. Paine; Dr. Wernher Von Braun, Marshall Center director; Colonel Clare F. Farley, Executive Officer in the Office Of The Administrator; and Charles J. Donlan, Deputy Associate Administrator for Manned Space Flight, Technical. the shoe Dr. Paine is holding has a unique fastener built into the sole to allow an astronaut to move about on the workshop floor and to remain in one position if he desires.

  11. John Keats: poet, patient, physician.

    PubMed

    Smith, H

    1984-01-01

    John Keats, son of an ostler , was born in London in 1795. Despite an early interest in literature he was, surprisingly, apprenticed to an apothecary and continued his medical training at Guy's Hospital, obtaining the Licentiate of the Society of Apothecaries in 1816. He never practiced medicine. His early poems were not well received, and for the young poet with very slender means, life was difficult. Tragedy was added to difficulty when tuberculosis, which had already caused the death of his mother and uncle, became apparent in his brother Tom, whom Keats nursed through his illness when the brothers were living together in Hampstead . Subsequently Keats developed the disease, but despite its rapid progress, he managed in a single year - 1819 - to produce some of the finest lyrical poetry in the language. He went to Italy in the hope of obtaining a cure but died in Rome in 1821, aged 25. Medicine certainly contributed to the man, but also something to the poet, Keats; his training and his family and personal experience of tuberculosis speak for themselves. More subtly , his medical experience influenced in some degree his ideas and even his choice of words. The interrelations of poet-patient and trainee-physician are examined in this essay. PMID:6377444

  12. Medicine in John Locke's philosophy.

    PubMed

    Sanchez-Gonzalez, M A

    1990-12-01

    John Locke's philosophy was deeply affected by medicine of his times. It was specially influenced by the medical thought and practice of Thomas Sydenham. Locke was a personal friend of Sydenham, expressed an avid interest in his work and shared his views and methods. The influence of Sydenham's medicine can be seen in the following areas of Locke's philosophy: his "plain historical method"; the emphasis on observation and sensory experience instead of seeking the essence of things; the rejection of hypotheses and principles; the refusal of research into final causes and inner mechanisms; the ideal of irrefutable evidence and skepticism on the possibilities of certainty in science. The science which for Locke held the highest paradigmatic value in his theory of knowledge was precisely medicine. To a great extent, Locke's Essay on Human Understanding can be understood as an attempt to justify, substantiate, and promote Sydenham's medical method. This method, generalized, was then proposed as an instrument for the elaboration of all natural sciences. PMID:2290077

  13. Acquired von Willebrand disease.

    PubMed

    Kumar, Shaji; Pruthi, Rajiv K; Nichols, William L

    2002-02-01

    Acquired von Willebrand disease (AvWD) is a relatively rare acquired bleeding disorder that usually occurs in elderly patients, in whom its recognition may be delayed. Patients usually present predominantly with mucocutaneous bleeding, with no previous history of bleeding abnormalities and no clinically meaningful family history. Various underlying diseases have been associated with AvWD, most commonly hematoproliferative disorders, including monoclonal gammopathies, lymphoproliferative disorders, and myeloproliferative disorders. The pathogenesis of AvWD remains incompletely understood but includes autoantibodies directed against the von Willebrand factor (vWF), leading to a more rapid clearance from the circulation or interference with its function, adsorption of vWF by tumor cells, and nonimmunologic mechanisms of destruction. Laboratory evaluation usually reveals a pattern of prolonged bleeding time and decreased levels of vWF antigen, ristocetin cofactor activity, and factor VIII coagulant activity consistent with a diagnosis of vWD. Acquired vWD is distinguished from the congenital form by age at presentation, absence of a personal and family history of bleeding disorders, and, often, presence of a hematoproliferative or autoimmune disorder. The severity of the bleeding varies considerably among patients. Therapeutic options include desmopressin and certain factor VIII concentrates that also contain vWF. Successful treatment of the associated illness can reverse the clinical and laboratory manifestations. Intravenous immunoglobulins have also shown some efficacy in the management of AvWD, especially cases associated with monoclonal gammopathies. Awareness of AvWD is essential for diagnosis and appropriate management. PMID:11838652

  14. [Inborn and acquired von Willebrand disease].

    PubMed

    Schneppenheim, R; Budde, U

    2008-12-01

    Von Willebrand disease (VWD) is known for its marked heterogeneity which was already recognized by von Willebrand in 1926. The basis of phenotypic differentiation are quantitative and qualitative or functional differences between the different types and subtypes of VWD. Clinical relevant facts for the practioner on diagnosis and therapy of von Willebrand disease and von Willebrand syndrome are presented. PMID:19132162

  15. [Inborn and acquired von Willebrand disease].

    PubMed

    Schneppenheim, R; Barthels, M; Budde, U

    2005-11-01

    Von Willebrand disease (VWD) is known for its marked heterogeneity which was already recognized by von Willebrand in 1926. The basis of phenotypic differentiation are quantitative and qualitative or functional differences between the different types and subtypes of VWD. Clinical relevant facts for the practitioner on diagnosis and therapy of von Willebrand disease and von Willebrand syndrome are presented. PMID:16395486

  16. Corporate Perspective: An Interview with John Sculley.

    ERIC Educational Resources Information Center

    Temares, M. Lewis

    1989-01-01

    John Sculley, the chairman of the board of Apple Computer, Inc., discusses information technology management, management strategies, network management, the Chief Information Officer, strategic planning, back-to-the-future planning, business and university joint ventures, and security issues. (MLW)

  17. Obituary: John Louis Perdrix (1926-2005)

    NASA Astrophysics Data System (ADS)

    Orchiston, W.

    2005-12-01

    On 27 June 2005 the Journal of Astronomical History and Heritage lost its founder and Australia lost one of its leading historians of astronomy when John Louis Perdrix died in Dubai after a brief battle with cancer.

  18. John Dewey--Philosopher and Educational Reformer

    ERIC Educational Resources Information Center

    Talebi, Kandan

    2015-01-01

    John Dewey was an American philosopher and educator, founder of the philosophical movement known as pragmatism, a pioneer in functional psychology, and a leader of the progressive movement in education in the United States.

  19. Archival Footage: John Glenn's Mercury Flight

    NASA Video Gallery

    Archival films document John Glenn's historic Feb. 20, 1962 Mercury flight in his Friendship 7, in which he became the first American to orbit the Earth. Clips include boarding the capsule, splashd...

  20. John Peter Zenger, Battler for Freedom

    ERIC Educational Resources Information Center

    Wallerstein, Gerry

    1974-01-01

    Examines the freedom of the press precedent set by the John Peter Zenger case in 1743 and considers its application to such current events as the jailing of reporters for not disclosing news sources. (RB)

  1. John Twysden and John Palmer: 17th-century Northamptonshire astronomers

    NASA Astrophysics Data System (ADS)

    Frost, M. A.

    2008-01-01

    John Twysden (1607-1688) and John Palmer (1612-1679) were two astronomers in the circle of Samuel Foster (circa 1600-1652), the subject of a recent paper in this journal. John Twysden qualified in law and medicine and led a peripatetic life around England and Europe. John Palmer was Rector of Ecton, Northamptonshire and later Archdeacon of Northampton. The two astronomers catalogued observations made from Northamptonshire from the 1640s to the 1670s. In their later years Twysden and Palmer published works on a variety of topics, often astronomical. Palmer engaged in correspondence with Henry Oldenburg, the first secretary of the Royal Society, on topics in astronomy and mathematics.

  2. John F. Kennedy Space Center

    NASA Technical Reports Server (NTRS)

    2006-01-01

    The John F. Kennedy Space Center, America's spaceport, is located along Florida's eastern shore on Cape Canaveral. Established as NASA's Launch Operations Center on July 1, 1962, the center has been the site of launching all U.S. human space flight missions, from the early days of Project Mercury to the space shuttle and the next generation of vehicles. In addition, the center is home to NASA's Launch Services Program, which coordinates all expendable vehicle launches carrying a NASA payload.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

    Size: 32.6 by 51.2 kilometers (20.2 by 32.2 miles) Location: 28.6 degrees North latitude, 80.6 degrees West longitude Orientation: North at top Image Data: ASTER bands 3, 2, and 1 Original Data Resolution: 15 meters (49

  3. Clinical Problem Solving: The Case of John, Part III

    ERIC Educational Resources Information Center

    Drell, Martin J.; Josephson, Allan; Pleak, Richard; Riggs, Paula; Rosenfeld, Alvin

    2006-01-01

    In this article, the authors share the case of John, a college freshman who had been struggling with depression. To work around John's case, the authors conducted an interview with John's parents. Based on the interview, it is found out that John's depression was largely caused by his relationship with his parents and the environment at their…

  4. Spectral analysis of approximations of Dirichlet-Neumann operators and nonlocal shallow water wave models

    NASA Astrophysics Data System (ADS)

    Vargas-Magaña, Rosa; Panayotaros, Panayotis

    2015-11-01

    We study the problem of wave propagation in a long-wave asymptotic regime over variable bottom of an ideal irrotational fluid in the framework of the Hamiltonian formulation in which the non-local Dirichlet-Neumann (DtN) operator appears explicitly in the Hamiltonian. We propose a non-local Hamiltonian model for bidirectional wave propagation in shallow water that involves pseudodifferential operators that approximate the DtN operator for variable depth. These models generalize the Boussinesq system as they include the exact dispersion relation in the case of constant depth. We present results for the normal modes and eigenfrequencies of the linearized problem. We see that variable topography introduces effects such as steepening of normal modes with increasing variation of depth, as well as amplitude modulation of the normal modes in certain wavelength ranges. Numerical integration shows that the constant depth nonlocal Boussinesq model with quadratic nonlinearity can capture the evolution obtained with higher order approximations of the DtN operator. In the case of variable depth we observe certain oscillations in width of the crest and also some interesting textures in the evolution of wave crests during the passage from obstacles.

  5. Blow-up problems for the heat equation with a local nonlinear Neumann boundary condition

    NASA Astrophysics Data System (ADS)

    Yang, Xin; Zhou, Zhengfang

    2016-09-01

    This paper estimates the blow-up time for the heat equation ut = Δu with a local nonlinear Neumann boundary condition: The normal derivative ∂ u / ∂ n =uq on Γ1, one piece of the boundary, while on the rest part of the boundary, ∂ u / ∂ n = 0. The motivation of the study is the partial damage to the insulation on the surface of space shuttles caused by high speed flying subjects. We show the finite time blow-up of the solution and estimate both upper and lower bounds of the blow-up time in terms of the area of Γ1. In many other work, they need the convexity of the domain Ω and only consider the problem with Γ1 = ∂ Ω. In this paper, we remove the convexity condition and only require ∂Ω to be C2. In addition, we deal with the local nonlinearity, namely Γ1 can be just part of ∂Ω.

  6. Moist turbulent Rayleigh-Bénard convection with Neumann and Dirichlet boundary conditions

    NASA Astrophysics Data System (ADS)

    Weidauer, Thomas; Schumacher, Jörg

    2012-07-01

    Turbulent Rayleigh-Bénard convection with phase changes in an extended layer between two parallel impermeable planes is studied by means of three-dimensional direct numerical simulations for Rayleigh numbers between 104 and 1.5 × 107 and for Prandtl number Pr = 0.7. Two different sets of boundary conditions of temperature and total water content are compared: imposed constant amplitudes which translate into Dirichlet boundary conditions for the scalar field fluctuations about the quiescent diffusive equilibrium and constant imposed flux boundary conditions that result in Neumann boundary conditions. Moist turbulent convection is in the conditionally unstable regime throughout this study for which unsaturated air parcels are stably and saturated air parcels unstably stratified. A direct comparison of both sets of boundary conditions with the same parameters requires to start the turbulence simulations out of differently saturated equilibrium states. Similar to dry Rayleigh-Bénard convection the differences in the turbulent velocity fluctuations, the cloud cover, and the convective buoyancy flux decrease across the layer with increasing Rayleigh number. At the highest Rayleigh numbers the system is found in a two-layer regime, a dry cloudless and stably stratified layer with low turbulence level below a fully saturated and cloudy turbulent one which equals a classical Rayleigh-Bénard convection layer. Both are separated by a strong inversion that gets increasingly narrower for growing Rayleigh number.

  7. Extraktion von DNA

    NASA Astrophysics Data System (ADS)

    Pöpping, Bert; Unterberger, Claudia

    Eine DNA-gestützte Analytik spielt im Lebensmittelbereich eine große Rolle. So wird die PCR bzw. die Real Time PCR z. B. für den Nachweis von Krankheitserreger in Lebensmitteln, zur Tier- und Pflanzenartendifferenzierung und den Nachweis von gentechnologisch veränderten Organismen eingesetzt [1]. Grundvoraussetzung für die sehr sensitiven molekularbiologischen Methoden ist eine saubere und kontaminationsfreie Nukleinsäure [2]. Die Qualität der Nukleinsäure entscheidet über Erfolg und Misserfolg der anschließenden molekularbiologischen Analytik. Deshalb werden im Bereich der Lebensmittelanalytik hohe Anforderungen an das jeweilige DNA-Extraktionsprotokoll gestellt. Durch die Anwendung eines geeigneten Extraktionsverfahrens soll die nachzuweisende DNA möglichst in hochmolekularer Form und frei von die nachfolgende Analytik hemmenden Substanzen vorliegen [1]. Gerade hier stellt die Natur der Lebensmittelmatrix eine besondere Herausforderung dar. Matrixkomponenten wie Fette, Zucker, Proteine und sekundäre Inhaltsstoffe erschweren die DNA-Extraktion und können, wenn sie nicht durch die Extraktion vollständig entfernt werden, zu einer Inhibierung der PCR führen [3]. Des Weiteren müssen auf der Matrixoberfläche vorhandene DNA-abbauende Enzyme gehemmt werden [1]. Daneben spielt der Einfluss verschiedener chemischer und physikalischer Parameter (pH-Wert, Temperatur, Enzyme, Scherkräfte) bei der Lebensmittelproduktion eine große Rolle für die Qualität der extrahierten DNA. So führen z. B. hohe Temperaturen und saure pH-Werte während der Lebensmittelverarbeitung zu einer Fragmentierung der DNA. Auch die physikalischen und chemischen Bedingungen der verwendeten Extraktionsmethode beeinflussen die Qualität der DNA [2]. Bleiben nach der Extraktion organische Lösungsmittel (Phenol, Ethanol), Enzyme, Proteine oder Salze zurück, können diese ebenfalls eine nachfolgende PCR inhibieren. Um eine Inhibition der PCR auszuschließen, sollten in der

  8. Dr. Wernher Von Braun

    NASA Technical Reports Server (NTRS)

    1960-01-01

    On September 8, 1960 President Dwight D. Eisenhower visited Huntsville, Alabama to dedicate a new NASA field center in honor of General George C. Marshall, Eisenhower's wartime colleague and the founder of the famous Marshall Plan for European recover after World War II. The new George C. Marshall Space Flight Center was placed under the control of Dr. Wernher Von Braun shown here talking with President Eisenhower. As parto f his remarks dedicating the center, President Eisenhowe refereed to General Marshall as a 'man of yar, yet a builder of peace'. the Marshall Center's first major assignment including building the huge Saturn V rocket that launched human beings on their first journey to the surface of the moon in 1969.

  9. Obituary: John W. Firor (1927-2007)

    NASA Astrophysics Data System (ADS)

    Gilman, Peter A.

    2009-12-01

    John W. Firor, a former Director of the High Altitude Observatory and the National Center for Atmospheric Research, and a founder of the Solar Physics Division of the American Astronomical Society, died of Alzheimer's disease in Pullman, Washington on November 5, 2007, he was 80. He was born in Athens Georgia on October 18, 1927, where his father was a professor of agricultural economics. John had an unusually diverse scientific career. His interest in physics and astrophysics began while serving in the army, during which time he was assigned to the Los Alamos National Laboratory, where he guarded highly radioactive materials (many have heard him describe how informal the protections were compared to later times). After his service he returned to college and graduated in physics from Georgia Tech in 1949. He received his Ph.D. from the University of Chicago in 1954, writing his thesis on cosmic rays under John Simpson. John Firor would later remark that: "If you needed cosmic rays to actually do anything, you are sunk." That thought, partly in jest, may help explain his motivation for moving to so many new scientific and management pursuits. John moved from cosmic ray physics to radio astronomy (particularly of the Sun) when he began work at the Carnegie Institution of Washington's Department of Terrestrial Magnetism, where he remained until 1961. During this time, he met Walter Orr Roberts, then the Director of the High Altitude Observatory (HAO) in Boulder, Colorado. HAO was then affiliated with the University of Colorado. In 1959, a movement began to upgrade the atmospheric sciences in the United States by establishing a National Center, where the largest, most important atmospheric research problems could be addressed. Roberts became the first Director of NCAR, as well as the first president of the University Corporation for Atmospheric Research (UCAR), the consortium of universities that was commissioned to manage and staff the new Center. HAO became a

  10. Von Hippel-Lindau Disease.

    PubMed

    Findeis-Hosey, Jennifer J; McMahon, Kelly Q; Findeis, Sarah K

    2016-06-01

    Von Hippel-Lindau disease is an autosomal dominant syndrome which occurs secondary to germline mutations in the VHL tumor suppressor gene, located on chromosome 3. Clinically von Hippel-Lindau disease is characterized by an increased risk of developing simple visceral cysts, most commonly in the pancreas and kidneys, in addition to an increased risk of developing neoplasms, often with clear cell features, in a multitude of organ systems. The most common neoplasms are cerebellar and retinal hemangioblastomas, adrenal pheochromocytomas, clear cell renal cell carcinomas, pancreatic neuroendocrine tumors, pancreatic serous cystadenomas, and endolymphatic sac tumors. These lesions most commonly present during adulthood; however, screening and surveillance for the development of these lesions should begin in the pediatric years for patients with von Hippel-Lindau disease. In this review article, the genetics and most common neoplasms of von Hippel-Lindau disease are reviewed, with an eye towards implications for the pediatric patient. PMID:27617152