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Sample records for mechanism manifests classical

  1. On the hypothesis that quantum mechanism manifests classical mechanics: Numerical approach to the correspondence in search of quantum chaos

    SciTech Connect

    Lee, Sang-Bong

    1993-09-01

    Quantum manifestation of classical chaos has been one of the extensively studied subjects for more than a decade. Yet clear understanding of its nature still remains to be an open question partly due to the lack of a canonical definition of quantum chaos. The classical definition seems to be unsuitable in quantum mechanics partly because of the Heisenberg quantum uncertainty. In this regard, quantum chaos is somewhat misleading and needs to be clarified at the very fundamental level of physics. Since it is well known that quantum mechanics is more fundamental than classical mechanics, the quantum description of classically chaotic nature should be attainable in the limit of large quantum numbers. The focus of my research, therefore, lies on the correspondence principle for classically chaotic systems. The chaotic damped driven pendulum is mainly studied numerically using the split operator method that solves the time-dependent Schroedinger equation. For classically dissipative chaotic systems in which (multi)fractal strange attractors often emerge, several quantum dissipative mechanisms are also considered. For instance, Hoover`s and Kubo-Fox-Keizer`s approaches are studied with some computational analyses. But the notion of complex energy with non-Hermiticity is extensively applied. Moreover, the Wigner and Husimi distribution functions are examined with an equivalent classical distribution in phase-space, and dynamical properties of the wave packet in configuration and momentum spaces are also explored. The results indicate that quantum dynamics embraces classical dynamics although the classicalquantum correspondence fails to be observed in the classically chaotic regime. Even in the semi-classical limits, classically chaotic phenomena would eventually be suppressed by the quantum uncertainty.

  2. Classical Mechanics

    NASA Astrophysics Data System (ADS)

    Chow, Tai L.

    1995-05-01

    Bring Classical Mechanics To Life With a Realistic Software Simulation! You can enhance the thorough coverage of Chow's Classical Mechanics with a hands-on, real-world experience! John Wiley & Sons, Inc. is proud to announce a new computer simulation for classical mechanics. Developed by the Consortium for Upper-Level Physics Software (CUPS), this simulation offers complex, often realistic calculations of models of various physical systems. Classical Mechanics Simulations (54881-2) is the perfect complement to Chow's text. Like all of the CUPS simulations, it is remarkably easy to use, yet sophisticated enough for explorations of new ideas. Other Important Features Include: * Six powerful simulations include: The Motion Generator, Rotation of Three-Dimensional Objects, Coupled Oscillators, Anharmonic Oscillators, Gravitational Orbits, and Collisions * Pascal source code for all programs is supplied and a number of exercises suggest specific ways the programs can be modified. * Simulations usually include graphical (often animated) displays. The entire CUPS simulation series consists of nine book/software simulations which comprise most of the undergraduate physics major's curriculum.

  3. Supersymmetry in classical mechanics

    NASA Astrophysics Data System (ADS)

    Suen, W. M.; Wong, C. W.; Young, K.

    2000-06-01

    The concept of supersymmetry extended to classical mechanics relates one-parameter families of Hamiltonians H( ξ, x, p)= p2+ V( ξ, x), such that the mapping from the phase space of H( ξ1, x, p) to that of H( ξ2, x, p) preserves time-evolution and conserves total energy; as a result, equal-energy periodic orbits in the two have the same period. While t-evolution is a contact transformation generated by H, ξ-evolution is a generalized contact transformation generated by a function K, and preserves phase volume except for a point sink (source) as ξ increases (decreases). Closed-form solutions of ξ-evolution include several well-known examples.

  4. Operator Formulation of Classical Mechanics.

    ERIC Educational Resources Information Center

    Cohn, Jack

    1980-01-01

    Discusses the construction of an operator formulation of classical mechanics which is directly concerned with wave packets in configuration space and is more similar to that of convential quantum theory than other extant operator formulations of classical mechanics. (Author/HM)

  5. Quantum localization of classical mechanics

    NASA Astrophysics Data System (ADS)

    Batalin, Igor A.; Lavrov, Peter M.

    2016-07-01

    Quantum localization of classical mechanics within the BRST-BFV and BV (or field-antifield) quantization methods are studied. It is shown that a special choice of gauge fixing functions (or BRST-BFV charge) together with the unitary limit leads to Hamiltonian localization in the path integral of the BRST-BFV formalism. In turn, we find that a special choice of gauge fixing functions being proportional to extremals of an initial non-degenerate classical action together with a very special solution of the classical master equation result in Lagrangian localization in the partition function of the BV formalism.

  6. Teaching Classical Mechanics Using Smartphones

    ERIC Educational Resources Information Center

    Chevrier, Joel; Madani, Laya; Ledenmat, Simon; Bsiesy, Ahmad

    2013-01-01

    A number of articles published in this column have dealt with topics in classical mechanics. This note describes some additional examples employing a smartphone and the new software iMecaProf. Steve Jobs presented the iPhone as "perfect for gaming." Thanks to its microsensors connected in real time to the numerical world, physics…

  7. Teaching classical mechanics using smartphones

    NASA Astrophysics Data System (ADS)

    Chevrier, Joel; Madani, Laya; Ledenmat, Simon; Bsiesy, Ahmad

    2013-09-01

    A number of articles published in this column have dealt with topics in classical mechanics. This note describes some additional examples employing a smartphone and the new software iMecaProf.4 Steve Jobs presented the iPhone as "perfect for gaming."5 Thanks to its microsensors connected in real time to the numerical world, physics teachers could add that smartphones are "perfect for teaching science." The software iMecaProf displays in real time the measured data on a screen. The visual representation is built upon the formalism of classical mechanics. iMecaProf receives data 100 times a second from iPhone sensors through a Wi-Fi connection using the application Sensor Data.6 Data are the three components of the acceleration vector in the smartphone frame and smartphone's orientation through three angles (yaw, pitch, and roll). For circular motion (uniform or not), iMecaProf uses independent measurements of the rotation angle θ, the angular speed dθ/dt, and the angular acceleration d2θ/dt2.

  8. Classical mechanics of nonconservative systems.

    PubMed

    Galley, Chad R

    2013-04-26

    Hamilton's principle of stationary action lies at the foundation of theoretical physics and is applied in many other disciplines from pure mathematics to economics. Despite its utility, Hamilton's principle has a subtle pitfall that often goes unnoticed in physics: it is formulated as a boundary value problem in time but is used to derive equations of motion that are solved with initial data. This subtlety can have undesirable effects. I present a formulation of Hamilton's principle that is compatible with initial value problems. Remarkably, this leads to a natural formulation for the Lagrangian and Hamiltonian dynamics of generic nonconservative systems, thereby filling a long-standing gap in classical mechanics. Thus, dissipative effects, for example, can be studied with new tools that may have applications in a variety of disciplines. The new formalism is demonstrated by two examples of nonconservative systems: an object moving in a fluid with viscous drag forces and a harmonic oscillator coupled to a dissipative environment.

  9. Dynamical Symmetries in Classical Mechanics

    ERIC Educational Resources Information Center

    Boozer, A. D.

    2012-01-01

    We show how symmetries of a classical dynamical system can be described in terms of operators that act on the state space for the system. We illustrate our results by considering a number of possible symmetries that a classical dynamical system might have, and for each symmetry we give examples of dynamical systems that do and do not possess that…

  10. Quantum manifestations of classical stochasticity. I. Energetics of some nonlinear systems

    NASA Astrophysics Data System (ADS)

    Weissman, Yitzhak; Jortner, Joshua

    1982-08-01

    In this paper we present the results of a semiclassical investigation and a quantum mechanical study of the bound energy spectrum of the Henon-Heiles Hamiltonian (HHH) and of the Barbanis Hamiltonian (BH). We have derived a simple semiclassical formula for the energy levels E, and for their sensitivity dE/dɛ with respect to the strength ɛ of the nonlinear coupling for the HHH, and established general relations between E and its derivatives dnE/dɛn (n⩾1). Numerical quantum mechanical computations of the energy levels were conducted for the HHH and for the BH. The nonlinear coupling constant was adjusted so that for the HHH there will be ˜150 states up to the classical critical energy Ec and ˜300 states up to the dissociation energy ED. The E values were obtained by direct diagonalization using a basis containing 760 states, while the values of dE/dɛ were computed utilizing the Hellmann-Feynman theorem. Good agreement between the semiclassical and the quantum mechanical spectra was observerd well above Ec. These results raise the distict possibility that the semiclassical approxmation for these nonlinear systems does not break down in the vicinity of Ec and that the bound level structure does not provide a manifestation of the classical transition from quasiperiodic to chaotic motion.

  11. Factors Influencing the Learning of Classical Mechanics.

    ERIC Educational Resources Information Center

    Champagne, Audrey B.; And Others

    1980-01-01

    Describes a study investigating the combined effect of certain variables on student achievement in classical mechanics. The purpose was to (1) describe preinstructional knowledge and skills; (2) correlate these variables with the student's success in learning classical mechanics; and (3) develop hypothesis about relationships between these…

  12. Bridging classical and quantum mechanics

    NASA Astrophysics Data System (ADS)

    Haddad, D.; Seifert, F.; Chao, L. S.; Li, S.; Newell, D. B.; Pratt, J. R.; Williams, C.; Schlamminger, S.

    2016-10-01

    Using a watt balance and a frequency comb, a mass-energy equivalence is derived. The watt balance compares mechanical power measured in terms of the meter, the second, and the kilogram to electrical power measured in terms of the volt and the ohm. A direct link between mechanical action and the Planck constant is established by the practical realization of the electrical units derived from the Josephson and the quantum Hall effects. By using frequency combs to measure velocities and acceleration of gravity, the unit of mass can be realized from a set of three defining constants: the Planck constant h, the speed of light c, and the hyperfine splitting frequency of 133Cs.

  13. Classical Mechanics Experiments using Wiimotes

    NASA Astrophysics Data System (ADS)

    Lopez, Alexander; Ochoa, Romulo

    2010-02-01

    The Wii, a video game console, is a very popular device. Although computationally it is not a powerful machine by today's standards, to a physics educator the controllers are its most important components. The Wiimote (or remote) controller contains a three-axis accelerometer, an infrared detector, and Bluetooth connectivity at a relatively low price. Thanks to available open source code, such as GlovePie, any PC or Laptop with Bluetooth capability can detect the information sent out by the Wiimote. We present experiments that use two or three Wiimotes simultaneously to measure the variable accelerations in two mass systems interacting via springs. Normal modes are determined from the data obtained. Masses and spring constants are varied to analyze their impact on the accelerations of the systems. We present the results of our experiments and compare them with those predicted using Lagrangian mechanics. )

  14. Thermodynamic integration from classical to quantum mechanics.

    PubMed

    Habershon, Scott; Manolopoulos, David E

    2011-12-14

    We present a new method for calculating quantum mechanical corrections to classical free energies, based on thermodynamic integration from classical to quantum mechanics. In contrast to previous methods, our method is numerically stable even in the presence of strong quantum delocalization. We first illustrate the method and its relationship to a well-established method with an analysis of a one-dimensional harmonic oscillator. We then show that our method can be used to calculate the quantum mechanical contributions to the free energies of ice and water for a flexible water model, a problem for which the established method is unstable.

  15. Comparison of Classical and Quantum Mechanical Uncertainties.

    ERIC Educational Resources Information Center

    Peslak, John, Jr.

    1979-01-01

    Comparisons are made for the particle-in-a-box, the harmonic oscillator, and the one-electron atom. A classical uncertainty principle is derived and compared with its quantum-mechanical counterpart. The results are discussed in terms of the statistical interpretation of the uncertainty principle. (Author/BB)

  16. Unraveling a classical mechanics brain twister

    NASA Astrophysics Data System (ADS)

    Paris, Norman; Broide, Michael L.

    2011-12-01

    We present a comprehensive analysis of an intriguing classical mechanics problem involving the coupled motion of two blocks. The problem illustrates fundamental physics concepts and theoretical techniques. We solve the equations of motion numerically and gain insight into common misconceptions about this system. The problem provides rich opportunities for student investigations using analytical and numerical methods.

  17. Time in classical and in quantum mechanics

    NASA Astrophysics Data System (ADS)

    Elçi, A.

    2010-07-01

    This paper presents an analysis of the time concept in classical mechanics from the perspective of the invariants of a motion. The analysis shows that there is a conceptual gap concerning time in the Dirac-Heisenberg-von Neumann formalism and that Bohr's complementarity principle does not fill the gap. In the Dirac-Heisenberg-von Neumann formalism, a particle's properties are represented by Heisenberg matrices. This axiom is the source of the time problem in quantum mechanics.

  18. Oral Manifestations of Plummer-Vinson Syndrome: A Classic Report with Literature Review

    PubMed Central

    Samad, Abdul; Mohan, N; Balaji, R V Suresh; Augustine, Dominic; Patil, Shankar Gouda

    2015-01-01

    Plummer-Vinson syndrome (PVS) is a triad of microcytic hypochromic anemia, atrophic glossitis, and esophageal webs or strictures. It is one of the syndromes associated with iron deficiency anemia. Symptoms resulting from anemia predominates the clinical picture, apart from the additional features such as glossitis, angular cheilitis, and dysphagia. Dysphagia is main clinical feature of PVS. PVS carries an increased risk of development of squamous cell carcinoma of esophagus and pharynx. A classic case report of PVS with clinical features, oral manifestations, malignant potential, differential diagnosis, investigation, dental implication, and treatment is discussed here with the literature review from the dentist’s point of view. The article carries a message that dental surgeons have to be familiar with the oral manifestations of anemia and be able to suspect PVS to aid in early diagnosis and prompt treatment. PMID:25878483

  19. Quantum approach to classical statistical mechanics.

    PubMed

    Somma, R D; Batista, C D; Ortiz, G

    2007-07-20

    We present a new approach to study the thermodynamic properties of d-dimensional classical systems by reducing the problem to the computation of ground state properties of a d-dimensional quantum model. This classical-to-quantum mapping allows us to extend the scope of standard optimization methods by unifying them under a general framework. The quantum annealing method is naturally extended to simulate classical systems at finite temperatures. We derive the rates to assure convergence to the optimal thermodynamic state using the adiabatic theorem of quantum mechanics. For simulated and quantum annealing, we obtain the asymptotic rates of T(t) approximately (pN)/(k(B)logt) and gamma(t) approximately (Nt)(-c/N), for the temperature and magnetic field, respectively. Other annealing strategies are also discussed.

  20. Statistical mechanics based on fractional classical and quantum mechanics

    SciTech Connect

    Korichi, Z.; Meftah, M. T.

    2014-03-15

    The purpose of this work is to study some problems in statistical mechanics based on the fractional classical and quantum mechanics. At first stage we have presented the thermodynamical properties of the classical ideal gas and the system of N classical oscillators. In both cases, the Hamiltonian contains fractional exponents of the phase space (position and momentum). At the second stage, in the context of the fractional quantum mechanics, we have calculated the thermodynamical properties for the black body radiation, studied the Bose-Einstein statistics with the related problem of the condensation and the Fermi-Dirac statistics.

  1. On Logical Error Underlying Classical Mechanics

    NASA Astrophysics Data System (ADS)

    Kalanov, Temur Z.

    2012-03-01

    The logical analysis of the general accepted description of mechanical motion of material point M in classical mechanics is proposed. The key idea of the analysis is as follows. Let point M be moved in the positive direction of the axis O 1ptx. Motion is characterized by a change of coordinate x,( t ) -- continuous function of time t(because motion is a change in general). If δ,->;0;δ,;=;0, then δ,;->;0δ,;=;0, i.e., according to practice and formal logic, value of coordinate does not change and, hence, motion does not exist. But, contrary to practice and formal logic, differential calculus and classical mechanics contain the assertion that velocity δ,;->;0;δ,δ,;exists without motion. Then velocity δ,;->;0;δ,δ,;is not real (i.e. not physical) quantity, but fictitious quantity. Therefore, use of non-physical (unreal) quantity (i.e. the first and second derivatives of function) in classical mechanics is a logic error.

  2. Macroscopic quantum mechanics in a classical spacetime.

    PubMed

    Yang, Huan; Miao, Haixing; Lee, Da-Shin; Helou, Bassam; Chen, Yanbei

    2013-04-26

    We apply the many-particle Schrödinger-Newton equation, which describes the coevolution of a many-particle quantum wave function and a classical space-time geometry, to macroscopic mechanical objects. By averaging over motions of the objects' internal degrees of freedom, we obtain an effective Schrödinger-Newton equation for their centers of mass, which can be monitored and manipulated at quantum levels by state-of-the-art optomechanics experiments. For a single macroscopic object moving quantum mechanically within a harmonic potential well, its quantum uncertainty is found to evolve at a frequency different from its classical eigenfrequency-with a difference that depends on the internal structure of the object-and can be observable using current technology. For several objects, the Schrödinger-Newton equation predicts semiclassical motions just like Newtonian physics, yet quantum uncertainty cannot be transferred from one object to another.

  3. Radiation nephritis. Clinical manifestations and pathophysiologic mechanisms

    SciTech Connect

    Krochak, R.J.; Baker, D.G.

    1986-05-01

    Radiation nephritis is both volume and dose related. Clinical experience would indicate that a minimum of one third of the renal volume needs to be excluded from nephrotoxic doses which appears to have a threshold of 2,000 cGy. The site of damage leading to renal failure appears to be the microvasculature ultimately expressed as glomerulosclerosis. How much direct damage to the tubular system contributes to this process is unclear, but undoubtedly the resultant systemic physiologic effects potentiate the expression of damage in the irradiated kidney. The acute syndrome, with all the potential manifestations of renal failure, rarely presents sooner than six months and appears to have no clear prodrome, although it would seem reasonable that a subclinical syndrome consisting of abnormalities detectable by urinalysis may occur. Treatment of radiation-induced nephritis or hypertension is no different from treatment for nephritis from any other cause and should be aggressive with lifelong follow-up. Carcinogenesis is a rare late expression of radiation-induced kidney damage. 25 references.

  4. Metal Ion Modeling Using Classical Mechanics.

    PubMed

    Li, Pengfei; Merz, Kenneth M

    2017-02-08

    Metal ions play significant roles in numerous fields including chemistry, geochemistry, biochemistry, and materials science. With computational tools increasingly becoming important in chemical research, methods have emerged to effectively face the challenge of modeling metal ions in the gas, aqueous, and solid phases. Herein, we review both quantum and classical modeling strategies for metal ion-containing systems that have been developed over the past few decades. This Review focuses on classical metal ion modeling based on unpolarized models (including the nonbonded, bonded, cationic dummy atom, and combined models), polarizable models (e.g., the fluctuating charge, Drude oscillator, and the induced dipole models), the angular overlap model, and valence bond-based models. Quantum mechanical studies of metal ion-containing systems at the semiempirical, ab initio, and density functional levels of theory are reviewed as well with a particular focus on how these methods inform classical modeling efforts. Finally, conclusions and future prospects and directions are offered that will further enhance the classical modeling of metal ion-containing systems.

  5. Metal Ion Modeling Using Classical Mechanics

    PubMed Central

    2017-01-01

    Metal ions play significant roles in numerous fields including chemistry, geochemistry, biochemistry, and materials science. With computational tools increasingly becoming important in chemical research, methods have emerged to effectively face the challenge of modeling metal ions in the gas, aqueous, and solid phases. Herein, we review both quantum and classical modeling strategies for metal ion-containing systems that have been developed over the past few decades. This Review focuses on classical metal ion modeling based on unpolarized models (including the nonbonded, bonded, cationic dummy atom, and combined models), polarizable models (e.g., the fluctuating charge, Drude oscillator, and the induced dipole models), the angular overlap model, and valence bond-based models. Quantum mechanical studies of metal ion-containing systems at the semiempirical, ab initio, and density functional levels of theory are reviewed as well with a particular focus on how these methods inform classical modeling efforts. Finally, conclusions and future prospects and directions are offered that will further enhance the classical modeling of metal ion-containing systems. PMID:28045509

  6. Optimum Onager: The Classical Mechanics of a Classical Siege Engine

    ERIC Educational Resources Information Center

    Denny, Mark

    2009-01-01

    The onager is a throwing weapon of classical antiquity, familiar to both the ancient Greeks and Romans. Here we analyze the dynamics of onager operation and derive the optimum angle for launching a projectile to its maximum range. There is plenty of scope for further considerations about increasing onager range, and so by thinking about how this…

  7. Classical and quantum-mechanical state reconstruction

    NASA Astrophysics Data System (ADS)

    Khanna, F. C.; Mello, P. A.; Revzen, M.

    2012-07-01

    The aim of this paper is to present the subject of state reconstruction in classical and in quantum physics, a subject that deals with the experimentally acquired information that allows the determination of the physical state of a system. Our first purpose is to explain a method for retrieving a classical state in phase space, similar to that used in medical imaging known as computer-aided tomography. It is remarkable that this method can be taken over to quantum mechanics, where it leads to a description of the quantum state in terms of the Wigner function which, although it may take on negative values, plays the role of the probability density in phase space in classical physics. We then present another approach to quantum state reconstruction based on the notion of mutually unbiased bases—a notion of current research interest, for which we give explanatory remarks—and indicate the relation between these two approaches. Since the subject of state reconstruction is rarely considered at the level of textbooks, the presentation in this paper is aimed at graduate-level readers.

  8. Optimum Onager: The Classical Mechanics of a Classical Siege Engine

    NASA Astrophysics Data System (ADS)

    Denny, Mark

    2009-12-01

    The onager is a throwing weapon of classical antiquity, familiar to both the ancient Greeks and Romans. Here we analyze the dynamics of onager operation and derive the optimum angle for launching a projectile to its maximum range. There is plenty of scope for further considerations about increasing onager range, and so by thinking about how this machine might be improved, a student can gain insight beyond the equations of motion and can test hypotheses on readily available working models. Some of these performance improvements are considered in this paper.

  9. Statistical origin of classical mechanics and quantum mechanics

    NASA Astrophysics Data System (ADS)

    Chu, Shu-Yuan

    1993-11-01

    The classical action for interacting strings, obtained by generalizing the time-symmetric electrodynamics of Wheeler and Feynman, is exactly additive. The additivity of the string action suggests a connection between the area of the string world sheets and entropy. We find that the action principle of classical mechanics is the condition that the total entropy of the strings be at an extremum, and the path-integral representation of the quantum density matrix element is an approximation to the partition function of the string theory.

  10. Statistical mechanics of quantum-classical systems with holonomic constraints.

    PubMed

    Sergi, Alessandro

    2006-01-14

    The statistical mechanics of quantum-classical systems with holonomic constraints is formulated rigorously by unifying the classical Dirac bracket and the quantum-classical bracket in matrix form. The resulting Dirac quantum-classical theory, which conserves the holonomic constraints exactly, is then used to formulate time evolution and statistical mechanics. The correct momentum-jump approximation for constrained systems arises naturally from this formalism. Finally, in analogy with what was found in the classical case, it is shown that the rigorous linear-response function of constrained quantum-classical systems contains nontrivial additional terms which are absent in the response of unconstrained systems.

  11. Classical and Quantum-Mechanical State Reconstruction

    ERIC Educational Resources Information Center

    Khanna, F. C.; Mello, P. A.; Revzen, M.

    2012-01-01

    The aim of this paper is to present the subject of state reconstruction in classical and in quantum physics, a subject that deals with the experimentally acquired information that allows the determination of the physical state of a system. Our first purpose is to explain a method for retrieving a classical state in phase space, similar to that…

  12. Classical phase space and statistical mechanics of identical particles.

    PubMed

    Hansson, T H; Isakov, S B; Leinaas, J M; Lindström, U

    2001-02-01

    Starting from the quantum theory of identical particles, we show how to define a classical mechanics that retains information about the quantum statistics. We consider two examples of relevance for the quantum Hall effect: identical particles in the lowest Landau level, and vortices in the Chern-Simons Ginzburg-Landau model. In both cases the resulting classical statistical mechanics is shown to be a nontrivial classical limit of Haldane's exclusion statistics.

  13. Supernovae in Binary Systems: An Application of Classical Mechanics.

    ERIC Educational Resources Information Center

    Mitalas, R.

    1980-01-01

    Presents the supernova explosion in a binary system as an application of classical mechanics. This presentation is intended to illustrate the power of the equivalent one-body problem and provide undergraduate students with a variety of insights into elementary classical mechanics. (HM)

  14. Coherently enhanced measurements in classical mechanics

    NASA Astrophysics Data System (ADS)

    Braun, Daniel; Popescu, Sandu

    2014-08-01

    In all quantitative sciences, it is common practice to increase the signal-to-noise ratio of noisy measurements by measuring identically prepared systems N times and averaging the measurement results. This leads to a scaling of the sensitivity as 1/√N, known in quantum measurement theory as the "standard quantum limit" (SQL). It is known that if one puts the N systems into an entangled state, a scaling as 1/N can be achieved, the socalled "Heisenberg limit" (HL), but decoherence problems have so far prevented implementation of such protocols for large N. Here we show that a method of coherent averaging inspired by a recent entanglement-free quantum enhanced measurement protocol is capable of achieving a sensitivity that scales as 1/N in a purely classical setup. This may substantially improve the measurement of very weak interactions in the classical realm, and, in particular, open a novel route to measuring the gravitational constant with enhanced precision.

  15. Complex Classical Mechanics of a QES Potential

    NASA Astrophysics Data System (ADS)

    Bhabani Prasad, Mandal; Sushant, S. Mahajan

    2015-10-01

    We study a combined parity (P) and time reversal (T) invariant non-Hermitian quasi-exactly solvable (QES) potential, which exhibits PT phase transition, in the complex plane classically to demonstrate different quantum effects. The particle with real energy makes closed orbits around one of the periodic wells of the complex potential depending on the initial condition. However interestingly the particle escapes to an open orbits even with real energy if it is placed beyond a certain distance from the center of the well. On the other hand when the particle energy is complex the trajectory is open and the particle tunnels back and forth between two wells which are separated by a classically forbidden path. The tunneling time is calculated for different pair of wells and is shown to vary inversely with the imaginary component of energy. Our study reveals that spontaneous PT symmetry breaking does not affect the qualitative features of the particle trajectories in the analogous complex classical model. Support from Department of Science and Technology (DST), Govt. of India under SERC Project Sanction Grant No. SR/S2/HEP-0009/2012

  16. Universal local symmetries and nonsuperposition in classical mechanics.

    PubMed

    Gozzi, Ennio; Pagani, Carlo

    2010-10-08

    In the Hilbert space formulation of classical mechanics, pioneered by Koopman and von Neumann, there are potentially more observables than in the standard approach to classical mechanics. In this Letter, we show that actually many of those extra observables are not invariant under a set of universal local symmetries which appear once the Koopman and von Neumann formulation is extended to include the evolution of differential forms. Because of their noninvariance, those extra observables have to be removed. This removal makes the superposition of states in the Koopman and von Neumann formulation, and as a consequence also in classical mechanics, impossible.

  17. Functional methods underlying classical mechanics, relativity and quantum theory

    NASA Astrophysics Data System (ADS)

    Kryukov, A.

    2013-04-01

    The paper investigates the physical content of a recently proposed mathematical framework that unifies the standard formalisms of classical mechanics, relativity and quantum theory. In the framework states of a classical particle are identified with Dirac delta functions. The classical space is "made" of these functions and becomes a submanifold in a Hilbert space of states of the particle. The resulting embedding of the classical space into the space of states is highly non-trivial and accounts for numerous deep relations between classical and quantum physics and relativity. One of the most striking results is the proof that the normal probability distribution of position of a macroscopic particle (equivalently, position of the corresponding delta state within the classical space submanifold) yields the Born rule for transitions between arbitrary quantum states.

  18. Hamilton's Principle and Approximate Solutions to Problems in Classical Mechanics

    ERIC Educational Resources Information Center

    Schlitt, D. W.

    1977-01-01

    Shows how to use the Ritz method for obtaining approximate solutions to problems expressed in variational form directly from the variational equation. Application of this method to classical mechanics is given. (MLH)

  19. A Computer-based Course in Classical Mechanics.

    ERIC Educational Resources Information Center

    Kane, D.; Sherwood, B.

    1980-01-01

    Describes and illustrates the tutorial and homework exercise lessons, student routing, course organization, administration, and evaluation of a PLATO computer-based course in classical mechanics. An appendix lists 41 lessons developed for the course. (CMV)

  20. Amphetamine toxicities Classical and emerging mechanisms

    PubMed Central

    Yamamoto, Bryan K.; Moszczynska, Anna; Gudelsky, Gary A.

    2014-01-01

    The drugs of abuse, methamphetamine and MDMA, produce long-term decreases in markers of biogenic amine neurotransmission. These decreases have been traditionally linked to nerve terminals and are evident in a variety of species, including rodents, nonhuman primates, and humans. Recent studies indicate that the damage produced by these drugs may be more widespread than originally believed. Changes indicative of damage to cell bodies of biogenic and nonbiogenic amine–containing neurons in several brain areas and endothelial cells that make up the blood–brain barrier have been reported. The processes that mediate this damage involve not only oxidative stress but also include excitotoxic mechanisms, neuroinflammation, the ubiquitin proteasome system, as well as mitochondrial and neurotrophic factor dysfunction. These mechanisms also underlie the toxicity associated with chronic stress and human immunodeficiency virus (HIV) infection, both of which have been shown to augment the toxicity to methamphetamine. Overall, multiple mechanisms are involved and interact to promote neurotoxicity to methamphetamine and MDMA. Moreover, the high coincidence of substituted amphetamine abuse by humans with HIV and/or chronic stress exposure suggests a potential enhanced vulnerability of these individuals to the neurotoxic actions of the amphetamines. PMID:20201848

  1. A wave equation interpolating between classical and quantum mechanics

    NASA Astrophysics Data System (ADS)

    Schleich, W. P.; Greenberger, D. M.; Kobe, D. H.; Scully, M. O.

    2015-10-01

    We derive a ‘master’ wave equation for a family of complex-valued waves {{Φ }}\\equiv R{exp}[{{{i}}S}({cl)}/{{\\hbar }}] whose phase dynamics is dictated by the Hamilton-Jacobi equation for the classical action {S}({cl)}. For a special choice of the dynamics of the amplitude R which eliminates all remnants of classical mechanics associated with {S}({cl)} our wave equation reduces to the Schrödinger equation. In this case the amplitude satisfies a Schrödinger equation analogous to that of a charged particle in an electromagnetic field where the roles of the scalar and the vector potentials are played by the classical energy and the momentum, respectively. In general this amplitude is complex and thereby creates in addition to the classical phase {S}({cl)}/{{\\hbar }} a quantum phase. Classical statistical mechanics, as described by a classical matter wave, follows from our wave equation when we choose the dynamics of the amplitude such that it remains real for all times. Our analysis shows that classical and quantum matter waves are distinguished by two different choices of the dynamics of their amplitudes rather than two values of Planck’s constant. We dedicate this paper to the memory of Richard Lewis Arnowitt—a pioneer of many-body theory, a path finder at the interface of gravity and quantum mechanics, and a true leader in non-relativistic and relativistic quantum field theory.

  2. Generalized Galilei-Invariant Classical Mechanics

    NASA Astrophysics Data System (ADS)

    Woodcock, Harry W.; Havas, Peter

    To describe the "slow" motions of n interacting mass points, we give the most general four-dimensional (4D) noninstantaneous, nonparticle symmetric Galilei-invariant variational principle. It involves two-body invariants constructed from particle 4-positions and 4-velocities of the proper orthochronous inhomogeneous Galilei group. The resulting 4D equations of motion and multiple-time conserved quantities involve integrals over the worldlines of the other n-1 interacting particles. For a particular time-asymmetric retarded (advanced) interaction, we show the vanishing of all integrals over worldlines in the ten standard 4D multiple-time conserved quantities, thus yielding a Newtonian-like initial value problem. This interaction gives 3D noninstantaneous, nonparticle symmetric, coupled nonlinear second-order delay-differential equations of motion that involve only algebraic combinations of nonsimultaneous particle positions, velocities, and accelerations. The ten 3D noninstantaneous, nonparticle symmetric conserved quantities involve only algebraic combinations of nonsimultaneous particle positions and velocities. A two-body example with a generalized Newtonian gravity is provided. We suggest that this formalism might be useful as an alternative slow-motion mechanics for astrophysical applications.

  3. Models on the boundary between classical and quantum mechanics.

    PubMed

    Hooft, Gerard 't

    2015-08-06

    Arguments that quantum mechanics cannot be explained in terms of any classical theory using only classical logic seem to be based on sound mathematical considerations: there cannot be physical laws that require 'conspiracy'. It may therefore be surprising that there are several explicit quantum systems where these considerations apparently do not apply. In this report, several such counterexamples are shown. These are quantum models that do have a classical origin. The most curious of these models is superstring theory. So now the question is asked: how can such a model feature 'conspiracy', and how bad is that? Is there conspiracy in the vacuum fluctuations? Arguments concerning Bell's theorem are further sharpened.

  4. Generalization of classical mechanics for nuclear motions on nonadiabatically coupled potential energy surfaces in chemical reactions.

    PubMed

    Takatsuka, Kazuo

    2007-10-18

    Classical trajectory study of nuclear motion on the Born-Oppenheimer potential energy surfaces is now one of the standard methods of chemical dynamics. In particular, this approach is inevitable in the studies of large molecular systems. However, as soon as more than a single potential energy surface is involved due to nonadiabatic coupling, such a naive application of classical mechanics loses its theoretical foundation. This is a classic and fundamental issue in the foundation of chemistry. To cope with this problem, we propose a generalization of classical mechanics that provides a path even in cases where multiple potential energy surfaces are involved in a single event and the Born-Oppenheimer approximation breaks down. This generalization is made by diagonalization of the matrix representation of nuclear forces in nonadiabatic dynamics, which is derived from a mixed quantum-classical representation of the electron-nucleus entangled Hamiltonian [Takatsuka, K. J. Chem. Phys. 2006, 124, 064111]. A manifestation of quantum fluctuation on a classical subsystem that directly contacts with a quantum subsystem is discussed. We also show that the Hamiltonian thus represented gives a theoretical foundation to examine the validity of the so-called semiclassical Ehrenfest theory (or mean-field theory) for electron quantum wavepacket dynamics, and indeed, it is pointed out that the electronic Hamiltonian to be used in this theory should be slightly modified.

  5. Craniofacial muscle pain: review of mechanisms and clinical manifestations.

    PubMed

    Svensson, P; Graven-Nielsen, T

    2001-01-01

    Epidemiologic surveys of temporomandibular disorders (TMD) have demonstrated that a considerable proportion of the population--up to 5% or 6%--will experience persistent pain severe enough to seek treatment. Unfortunately, the current diagnostic classification of craniofacial muscle pain is based on descriptions of signs and symptoms rather than on knowledge of pain mechanisms. Furthermore, the pathophysiology and etiology of craniofacial muscle pain are not known in sufficient detail to allow causal treatment. Many hypotheses have been proposed to explain cause-effect relationships; however, it is still uncertain what may be the cause of muscle pain and what is the effect of muscle pain. This article reviews the literature in which craniofacial muscle pain has been induced by experimental techniques in animals and human volunteers and in which the effects on somatosensory and motor function have been assessed under standardized conditions. This information is compared to the clinical correlates, which can be derived from the numerous cross-sectional studies in patients with craniofacial muscle pain. The experimental literature clearly indicates that muscle pain has significant effects on both somatosensory and craniofacial motor function. Typical somatosensory manifestations of experimental muscle pain are referred pain and increased sensitivity of homotopic areas. The craniofacial motor function is inhibited mainly during experimental muscle pain, but phase-dependent excitation is also found during mastication to reduce the amplitude and velocity of jaw movements. The underlying neurobiologic mechanisms probably involve varying combinations of sensitization of peripheral afferents, hyperexcitability of central neurons, and imbalance in descending pain modulatory systems. Reflex circuits in the brain stem seem important for the adjustment of sensorimotor function in the presence of craniofacial pain. Changes in somatosensory and motor function may therefore be

  6. Errata report on Herbert Goldstein's Classical Mechanics: Second edition

    SciTech Connect

    Unseren, M.A.; Hoffman, F.M.

    1993-01-01

    This report describes errors in Herbert Goldstein's textbook Classical Mechanics, Second Edition (Copyright 1980, ISBN 0-201-02918-9). Some of the errors in current printings of the text were corrected in the second printing; however, after communicating with Addison Wesley, the publisher for Classical Mechanics, it was discovered that the corrected galley proofs had been lost by the printer and that no one had complained of any errors in the eleven years since the second printing. The errata sheet corrects errors from all printings of the second edition.

  7. Equivalent emergence of time dependence in classical and quantum mechanics

    NASA Astrophysics Data System (ADS)

    Briggs, John S.

    2015-05-01

    Beginning with the principle that a closed mechanical composite system is timeless, time can be defined by the regular changes in a suitable position coordinate (clock) in the observing part, when one part of the closed composite observes another part. Translating this scenario into both classical and quantum mechanics allows a transition to be made from a time-independent mechanics for the closed composite to a time-dependent description of the observed part alone. The use of Hamilton-Jacobi theory yields a very close parallel between the derivations in classical and quantum mechanics. The time-dependent equations, Hamilton-Jacobi or Schrödinger, appear as approximations since no observed system is truly closed. The quantum case has an additional feature in the condition that the observing environment must become classical in order to define a real classical time variable. This condition leads to a removal of entanglement engendered by the interaction between the observed system and the observing environment. Comparison is made to the similar emergence of time in quantum gravity theory.

  8. A Primer on Elliptic Functions with Applications in Classical Mechanics

    ERIC Educational Resources Information Center

    Brizard, Alain J.

    2009-01-01

    The Jacobi and Weierstrass elliptic functions used to be part of the standard mathematical arsenal of physics students. They appear as solutions of many important problems in classical mechanics: the motion of a planar pendulum (Jacobi), the motion of a force-free asymmetric top (Jacobi), the motion of a spherical pendulum (Weierstrass) and the…

  9. Classical and quantum mechanics of diatomic molecules in tilted fields.

    PubMed

    Arango, Carlos A; Kennerly, William W; Ezra, Gregory S

    2005-05-08

    We investigate the classical and quantum mechanics of diatomic molecules in noncollinear (tilted) static electric and nonresonant linearly polarized laser fields. The classical diatomic in tilted fields is a nonintegrable system, and we study the phase space structure for physically relevant parameter regimes for the molecule KCl. While exhibiting low-energy (pendular) and high-energy (free-rotor) integrable limits, the rotor in tilted fields shows chaotic dynamics at intermediate energies, and the degree of classical chaos can be tuned by changing the tilt angle. We examine the quantum mechanics of rotors in tilted fields. Energy-level correlation diagrams are computed, and the presence of avoided crossings quantified by the study of nearest-neighbor spacing distributions as a function of energy and tilting angle. Finally, we examine the influence of classical periodic orbits on rotor wave functions. Many wave functions in the tilted field case are found to be highly nonseparable in spherical polar coordinates. Localization of wave functions in the vicinity of classical periodic orbits, both stable and unstable, is observed for many states.

  10. Neurological counterparts of hyponatremia: pathological mechanisms and clinical manifestations.

    PubMed

    Podestà, Manuel Alfredo; Faravelli, Irene; Cucchiari, David; Reggiani, Francesco; Oldani, Silvia; Fedeli, Carlo; Graziani, Giorgio

    2015-04-01

    Hyponatremia, defined as a serum sodium concentration <135 mEq/L, represents the most frequent electrolyte disorder in older hospitalized patients. Early recognition of hyponatremia is mandatory, since it represents an independent risk factor that increases hospital mortality by 40 %. Delayed correction of hyponatremia may worsen brain edema, resulting in different degrees of neural damage. However, an overly rapid correction of serum sodium levels can lead to osmotic demyelination syndrome (ODS), a dreadful neurological picture. In recent years, hyponatremia and ODS have received growing attention both in terms of clinical management and pathophysiology, leading to the discovery of new drugs and treatment algorithms. In this review, we recapitulate the pathogenetic background, clinical manifestations, and treatment guidelines of hyponatremia, focusing on the neurological alterations. Neurological symptoms may be neglected when they manifest as early signs of mild hyponatremia, while brain damage can irremediably affect patients' conditions in the context of ODS.

  11. Some Complex Pressure Effects on Spectra from Simple Classical Mechanics

    NASA Astrophysics Data System (ADS)

    Hartmann, Jean-Michel

    2016-06-01

    I will first recall how [the two Newton's equations, 1rst year of university] one can very easily compute the rotational and translational classical dynamics of an ensemble of linear molecules interacting through an (input) pair-wise intermolecular potential. These Classical Molecular Dynamics Simulations (CMDS), which provide the time dependence of the positions and axis-orientations of gas phase molecules, are then used to calculate a number of pressure effects manifesting in absorption and scattering spectra. The cases of CO2, O2 and N2 will be considered, systems for which fully quantum approaches are intractable, and comparisons with measured data will be made, free of any adjusted parameter. I will show that, with a few input ingredients from literature (molecule geometry, electric multipoles, polarizabilities, ...) an no adjusted parameter, excellent agreements with various measurements are obtained. Examples will be given for: (1) Collision induced absorption (due to the interaction induced dipole) ; (2) The far wings of absorption (due to the dipole) and light scattering (due to polarizability) bands ; (3) The broadening and shapes (with their deviations from the Voigt profile) of individual absorption lines for both "free" and spatially tightly confined gases. If times allows, additional demonstrations of the interest of CMDS will be given by considering line-mixing effects and the relaxation of laser-kicked molecules.

  12. Nasopharyngeal Tuberculosis: Epidemiology, Mechanism of Infection, Clinical Manifestations, and Management

    PubMed Central

    Sittitrai, Pichit

    2016-01-01

    Nasopharyngeal tuberculosis (NPTB) is a noteworthy disease especially in its worldwide spread of the Mycobacterium infection. Although NPTB has been identified in less than one percent of TB cases, recent multiple case reports indicate an either increased awareness or incidence of this disease. The most helpful diagnostic tool is an uncomplicated nasopharyngeal biopsy. However, NPTB is usually ignored because it has varied clinical manifestations and similar presentations with other more common head and neck diseases. Furthermore, the most common presenting symptom is cervical lymphadenopathy mimicking nasopharyngeal carcinoma, a more common and serious disease. Treatment outcomes of NPTB are good in both HIV-positive or HIV-negative patients. In addition, pulmonary tuberculosis association was reported in wide range between 8.3% and 82% which should be considered in a treatment program. In conclusion, early diagnosis and management in NPTB can be achieved by (1) increased awareness of this disease, (2) improvement in knowledge regarding clinical manifestations, and (3) improvement of diagnostic techniques. PMID:27034677

  13. Nasopharyngeal Tuberculosis: Epidemiology, Mechanism of Infection, Clinical Manifestations, and Management.

    PubMed

    Srivanitchapoom, Chonticha; Sittitrai, Pichit

    2016-01-01

    Nasopharyngeal tuberculosis (NPTB) is a noteworthy disease especially in its worldwide spread of the Mycobacterium infection. Although NPTB has been identified in less than one percent of TB cases, recent multiple case reports indicate an either increased awareness or incidence of this disease. The most helpful diagnostic tool is an uncomplicated nasopharyngeal biopsy. However, NPTB is usually ignored because it has varied clinical manifestations and similar presentations with other more common head and neck diseases. Furthermore, the most common presenting symptom is cervical lymphadenopathy mimicking nasopharyngeal carcinoma, a more common and serious disease. Treatment outcomes of NPTB are good in both HIV-positive or HIV-negative patients. In addition, pulmonary tuberculosis association was reported in wide range between 8.3% and 82% which should be considered in a treatment program. In conclusion, early diagnosis and management in NPTB can be achieved by (1) increased awareness of this disease, (2) improvement in knowledge regarding clinical manifestations, and (3) improvement of diagnostic techniques.

  14. Physical analogy between continuum thermodynamics and classical mechanics.

    PubMed

    Umantsev, Alex

    2004-01-01

    The main focus of this paper is the profound physical analogy between a continuum thermodynamical system, which evolves with relaxation under (possibly) nonisothermal conditions, and a classical mechanical system of a few interacting particles moving with dissipation in (possibly), time-dependent nonconservative fields. This analogy is applied to the problem of phase transitions in a one-dimensional thermodynamic system. The thermomechanical analogy stems from the validity of variational methods in mechanics and thermodynamics and allows for a different interpretation of the dynamical selection principle in the theory of pattern formation. This physical analogy is very helpful for understanding different nonlinear thermodynamic phenomena and for developing intuition in numerical simulations.

  15. Transfer from classical mechanics context to electricity and magnetism context

    NASA Astrophysics Data System (ADS)

    Gonzalez, Maria D.; Kanim, Stephen

    2008-10-01

    Some classical mechanics concepts, like density, vectors use, conservative fields, 3^rd Newton Law, velocity and acceleration physical and mathematical relations, are the basis for the development of related concepts that are central to the subsequent electricity and magnetism course. We believe that if students and instructors involved recognize the underlying features that are common to the two contexts, a better understanding and performance will be achieved. We are developing a pre- and post-test that is intended to measure the extent to which (1) students enter the electricity and magnetism course with a sufficient mechanics foundation; (2) there is a correlation between student responses to similar questions in mechanics and electrostatics contexts; and (3) mechanics understanding is strengthened through reintroduction of physics principles in a second context. We will give examples of ``paired'' questions and give data from administrations of the pre- and post-tests.

  16. Gauge transformations and conserved quantities in classical and quantum mechanics

    NASA Astrophysics Data System (ADS)

    Berche, Bertrand; Malterre, Daniel; Medina, Ernesto

    2016-08-01

    We are taught that gauge transformations in classical and quantum mechanics do not change the physics of the problem. Nevertheless, here we discuss three broad scenarios where under gauge transformations: (i) conservation laws are not preserved in the usual manner; (ii) non-gauge-invariant quantities can be associated with physical observables; and (iii) there are changes in the physical boundary conditions of the wave function that render it non-single-valued. We give worked examples that illustrate these points, in contrast to general opinions from classic texts. We also give a historical perspective on the development of Abelian gauge theory in relation to our particular points. Our aim is to provide a discussion of these issues at the graduate level.

  17. The simplified Fermi accelerator in classical and quantum mechanics

    NASA Astrophysics Data System (ADS)

    Karner, Gunther

    1994-11-01

    We review the simplified classical Fermi acceleration mechanism and construct a quantum counterpart by imposing time-dependent boundary conditions on solutions of the "free" Schrödinger equation at the unit interval. We find similiar dynamical features in the sense that limiting KAM curves, respectively purely singular quasienergy spectrum, exist(s) for sufficiently smooth "wall oscillations" (typically of C 2 type). In addition, we investigate quantum analogs to local approximations of the Fermi map both in its quasiperiodic and irregular phase space regions. In particular, we find pure point q.e. spectrum in the former case and conjecture that "random boundary conditions" are necessary to model a quantum analog to the chaotic regime of the classical accelerator.

  18. Physics on the boundary between classical and quantum mechanics

    NASA Astrophysics Data System (ADS)

    't Hooft, Gerard

    2014-04-01

    Nature's laws in the domain where relativistic effects, gravitational effects and quantum effects are all comparatively strong are far from understood. This domain is called the Planck scale. Conceivably, a theory can be constructed where the quantum nature of phenomena at such scales can be attributed to something fundamentally simpler. However, arguments that quantum mechanics cannot be explained in terms of any classical theory using only classical logic seem to be based on sound mathematical considerations: there can't be physical laws that require "conspiracy". It may therefore be surprising that there are several explicit quantum systems where these considerations apparently do not apply. In the lecture we will show several such counterexamples. These are quantum models that do have a classical origin. The most curious of these models is superstring theory. This theory is often portrayed as to underly the quantum field theory of the subatomic particles, including the "Standard Model". So now the question is asked: how can this model feature "conspiracy", and how bad is that? Is there conspiracy in the vacuum fluctuations?

  19. Operational dynamic modeling transcending quantum and classical mechanics.

    PubMed

    Bondar, Denys I; Cabrera, Renan; Lompay, Robert R; Ivanov, Misha Yu; Rabitz, Herschel A

    2012-11-09

    We introduce a general and systematic theoretical framework for operational dynamic modeling (ODM) by combining a kinematic description of a model with the evolution of the dynamical average values. The kinematics includes the algebra of the observables and their defined averages. The evolution of the average values is drawn in the form of Ehrenfest-like theorems. We show that ODM is capable of encompassing wide-ranging dynamics from classical non-relativistic mechanics to quantum field theory. The generality of ODM should provide a basis for formulating novel theories.

  20. Minimum length from quantum mechanics and classical general relativity.

    PubMed

    Calmet, Xavier; Graesser, Michael; Hsu, Stephen D H

    2004-11-19

    We derive fundamental limits on measurements of position, arising from quantum mechanics and classical general relativity. First, we show that any primitive probe or target used in an experiment must be larger than the Planck length lP. This suggests a Planck-size minimum ball of uncertainty in any measurement. Next, we study interferometers (such as LIGO) whose precision is much finer than the size of any individual components and hence are not obviously limited by the minimum ball. Nevertheless, we deduce a fundamental limit on their accuracy of order lP. Our results imply a device independent limit on possible position measurements.

  1. PT symmetry in classical and quantum statistical mechanics.

    PubMed

    Meisinger, Peter N; Ogilvie, Michael C

    2013-04-28

    PT-symmetric Hamiltonians and transfer matrices arise naturally in statistical mechanics. These classical and quantum models often require the use of complex or negative weights and thus fall outside the conventional equilibrium statistical mechanics of Hermitian systems. PT-symmetric models form a natural class where the partition function is necessarily real, but not necessarily positive. The correlation functions of these models display a much richer set of behaviours than Hermitian systems, displaying sinusoidally modulated exponential decay, as in a dense fluid, or even sinusoidal modulation without decay. Classical spin models with PT-symmetry include Z(N) models with a complex magnetic field, the chiral Potts model and the anisotropic next-nearest-neighbour Ising model. Quantum many-body problems with a non-zero chemical potential have a natural PT-symmetric representation related to the sign problem. Two-dimensional quantum chromodynamics with heavy quarks at non-zero chemical potential can be solved by diagonalizing an appropriate PT-symmetric Hamiltonian.

  2. Classical mechanics approach applied to analysis of genetic oscillators.

    PubMed

    Vasylchenkova, Anastasiia; Mraz, Miha; Zimic, Nikolaj; Moskon, Miha

    2016-04-05

    Biological oscillators present a fundamental part of several regulatory mechanisms that control the response of various biological systems. Several analytical approaches for their analysis have been reported recently. They are, however, limited to only specific oscillator topologies and/or to giving only qualitative answers, i.e., is the dynamics of an oscillator given the parameter space oscillatory or not. Here we present a general analytical approach that can be applied to the analysis of biological oscillators. It relies on the projection of biological systems to classical mechanics systems. The approach is able to provide us with relatively accurate results in the meaning of type of behaviour system reflects (i.e. oscillatory or not) and periods of potential oscillations without the necessity to conduct expensive numerical simulations. We demonstrate and verify the proposed approach on three different implementations of amplified negative feedback oscillator.

  3. Semi-classical modeling of nano-mechanical transistors

    NASA Astrophysics Data System (ADS)

    Scorrano, Alessandro; Carcaterra, Antonio

    2013-08-01

    The introduction of vibration-based Nano Electro-Mechanical Transistors (NEMT) opens a new horizon for mechanics in computer science. NEMT working principle is based on an electrical charge shuttle between two electrodes operated by a vibrating conductor body. Advantages of these novel devices would be very low power dissipation, limited influence of external electromagnetic disturbances, and improved thermal resistance. The paper introduces an analytical model for such a device, in which the matching of a mechanical resonator and an electric circuit is studied: the coupling is provided by capacitance effects, electrostatic force and the quantum tunneling. The approach is quasi-classical, describing the quantum phenomena through a non-linear conductance and using a continuous variable for the charges. Through suitably introduced simplifications, the model is reduced to a set of two differential equations in terms of pillar position and charge. These equations represent the simplest model still preserving the basic phenomenology of the investigated system. Numerical simulations show different possible motion regimes, both in the single- and multiple-module configurations, the latter able to reproduce the conventional transistor functionality. This opens the way to mechanical voltage-driven switches or amplifiers.

  4. Acceleration of Classical Mechanics by Phase Space Constraints.

    PubMed

    Martínez-Núñez, Emilio; Shalashilin, Dmitrii V

    2006-07-01

    In this article phase space constrained classical mechanics (PSCCM), a version of accelerated dynamics, is suggested to speed up classical trajectory simulations of slow chemical processes. The approach is based on introducing constraints which lock trajectories in the region of the phase space close to the dividing surface, which separates reactants and products. This results in substantial (up to more than 2 orders of magnitude) speeding up of the trajectory simulation. Actual microcanonical rates are calculated by introducing a correction factor equal to the fraction of the phase volume which is allowed by the constraints. The constraints can be more complex than previously used boosting potentials. The approach has its origin in Intramolecular Dynamics Diffusion Theory, which shows that the majority of nonstatistical effects are localized near the transition state. An excellent agreement with standard trajectory simulation at high energies and Monte Carlo Transition State Theory at low energies is demonstrated for the unimolecular dissociation of methyl nitrite, proving that PSCCM works both in statistical and nonstatistical regimes.

  5. Toughness of carbon nanotubes conforms to classic fracture mechanics.

    PubMed

    Yang, Lin; Greenfeld, Israel; Wagner, H Daniel

    2016-02-01

    Defects in crystalline structure are commonly believed to degrade the ideal strength of carbon nanotubes. However, the fracture mechanisms induced by such defects, as well as the validity of solid mechanics theories at the nanoscale, are still under debate. We show that the fracture toughness of single-walled nanotubes (SWNTs) conforms to the classic theory of fracture mechanics, even for the smallest possible vacancy defect (~2 Å). By simulating tension of SWNTs containing common types of defects, we demonstrate how stress concentration at the defect boundary leads to brittle (unstable) fracturing at a relatively low strain, degrading the ideal strength of SWNTs by up to 60%. We find that, owing to the SWNT's truss-like structure, defects at this scale are not sharp and stress concentrations are finite and low. Moreover, stress concentration, a geometric property at the macroscale, is interrelated with the SWNT fracture toughness, a material property. The resulting SWNT fracture toughness is 2.7 MPa m(0.5), typical of moderately brittle materials and applicable also to graphene.

  6. Toughness of carbon nanotubes conforms to classic fracture mechanics

    PubMed Central

    Yang, Lin; Greenfeld, Israel; Wagner, H. Daniel

    2016-01-01

    Defects in crystalline structure are commonly believed to degrade the ideal strength of carbon nanotubes. However, the fracture mechanisms induced by such defects, as well as the validity of solid mechanics theories at the nanoscale, are still under debate. We show that the fracture toughness of single-walled nanotubes (SWNTs) conforms to the classic theory of fracture mechanics, even for the smallest possible vacancy defect (~2 Å). By simulating tension of SWNTs containing common types of defects, we demonstrate how stress concentration at the defect boundary leads to brittle (unstable) fracturing at a relatively low strain, degrading the ideal strength of SWNTs by up to 60%. We find that, owing to the SWNT’s truss-like structure, defects at this scale are not sharp and stress concentrations are finite and low. Moreover, stress concentration, a geometric property at the macroscale, is interrelated with the SWNT fracture toughness, a material property. The resulting SWNT fracture toughness is 2.7 MPa m0.5, typical of moderately brittle materials and applicable also to graphene. PMID:26989774

  7. Geometric control of quantum mechanical and nonlinear classical systems

    NASA Astrophysics Data System (ADS)

    Nelson, Richard Joseph

    1999-10-01

    Geometric control refers to the judicious use of the non- commuting nature of inputs and natural dynamics as the basis for control. The last few decades in control system theory have seen the application of differential geometry in proving several important properties of systems, including controllability and observability. Until recently, however, the results of this mathematical geometry have rarely been used as the basis for designing and implementing an actual controller. This thesis demonstrates the application of a judicious selection of inputs, so that if the system is proven to be controllable using geometric methods, one can design input sequences using the same geometry. A demonstration of this method is shown in simulating the attitude control of a satellite: a highly non-linear, non- holonomic control problem. Although not a practical method for large re-orientations of a typical satellite, the approach can be applied to other nonlinear systems. The method is also applied to the closed-loop performance of a quantum mechanical system to demonstrate the feasibility of coherent quantum feedback-something impossible using a conventional controller. Finally, the method is applied in the open-loop control of a quantum mechanical system: in this case, the creation of Greenberger-Horne-Zeilinger correlations among the nuclei of an ensemble of alanine molecules in a nuclear magnetic resonance spectrometer. In each case, the data demonstrate the usefulness of a geometric approach to control. In addition to demonstrations of geometric control in practice, the quantum mechanical experiments also demonstrate for the first time peculiar quantum correlations, including GHZ correlations, that have no classical analog. The quantum experiments further establish nuclear magnetic resonance as a viable and accessible testbed of quantum predictions and processes. (Copies available exclusively from MIT Libraries, Rm. 14- 0551, Cambridge, MA 02139-4307. Ph. 617-253-5668; Fax

  8. Fundamental Principles of Classical Mechanics: a Geometrical Perspectives

    NASA Astrophysics Data System (ADS)

    Lam, Kai S.

    2014-07-01

    Classical mechanics is the quantitative study of the laws of motion for oscopic physical systems with mass. The fundamental laws of this subject, known as Newton's Laws of Motion, are expressed in terms of second-order differential equations governing the time evolution of vectors in a so-called configuration space of a system (see Chapter 12). In an elementary setting, these are usually vectors in 3-dimensional Euclidean space, such as position vectors of point particles; but typically they can be vectors in higher dimensional and more abstract spaces. A general knowledge of the mathematical properties of vectors, not only in their most intuitive incarnations as directed arrows in physical space but as elements of abstract linear vector spaces, and those of linear operators (transformations) on vector spaces as well, is then indispensable in laying the groundwork for both the physical and the more advanced mathematical - more precisely topological and geometrical - concepts that will prove to be vital in our subject. In this beginning chapter we will review these properties, and introduce the all-important related notions of dual spaces and tensor products of vector spaces. The notational convention for vectorial and tensorial indices used for the rest of this book (except when otherwise specified) will also be established...

  9. Quantum mechanical ground state of hydrogen obtained from classical electrodynamics

    NASA Astrophysics Data System (ADS)

    Cole, Daniel C.; Zou, Yi

    2003-10-01

    The behavior of a classical charged point particle under the influence of only a Coulombic binding potential and classical electromagnetic zero-point radiation, is shown to agree closely with the probability density distribution of Schrödinger's wave equation for the ground state of hydrogen. These results again raise the possibility that the main tenets of stochastic electrodynamics (SED) are correct.

  10. Revisiting the Molecular Mechanism of Neurological Manifestations in Antiphospholipid Syndrome: Beyond Vascular Damage

    PubMed Central

    Carecchio, M.; Cantello, R.; Comi, C.

    2014-01-01

    Antiphospholipid syndrome (APS) is a multiorgan disease often affecting the central nervous system (CNS). Typically, neurological manifestations of APS include thrombosis of cerebral vessels leading to stroke and requiring prompt initiation of treatment with antiplatelet drugs or anticoagulant therapy. In these cases, alterations of the coagulation system at various levels caused by multiple effects of antiphospholipid antibodies (aPL) have been postulated to explain the vascular damage to the CNS in APS. However, several nonvascular neurological manifestations of APS have progressively emerged over the past years. Nonthrombotic, immune-mediated mechanisms altering physiological basal ganglia function have been recently suggested to play a central role in the pathogenesis of these manifestations that include, among others, movement disorders such as chorea and behavioral and cognitive alterations. Similar clinical manifestations have been described in other autoimmune CNS diseases such as anti-NMDAR and anti-VGCK encephalitis, suggesting that the spectrum of immune-mediated basal ganglia disorders is expanding, possibly sharing some pathophysiological mechanisms. In this review, we will focus on thrombotic and nonthrombotic neurological manifestations of APS with particular attention to immune-mediated actions of aPL on the vascular system and the basal ganglia. PMID:24741580

  11. On the Green-functions of the classical off-shell electrodynamics under the manifestly covariant relativistic dynamics of Stueckelberg

    NASA Astrophysics Data System (ADS)

    Aharonovich, I.; Horwitz, L. P.

    2011-08-01

    In previous papers derivations of the Green function have been given for 5D off-shell electrodynamics in the framework of the manifestly covariant relativistic dynamics of Stueckelberg (with invariant evolution parameter τ). In this paper, we reconcile these derivations resulting in different explicit forms, and relate our results to the conventional fundamental solutions of linear 5D wave equations published in the mathematical literature. We give physical arguments for the choice of the Green function retarded in the fifth variable τ.

  12. Altered brain mechanisms of emotion processing in pre-manifest Huntington's disease.

    PubMed

    Novak, Marianne J U; Warren, Jason D; Henley, Susie M D; Draganski, Bogdan; Frackowiak, Richard S; Tabrizi, Sarah J

    2012-04-01

    Huntington's disease is an inherited neurodegenerative disease that causes motor, cognitive and psychiatric impairment, including an early decline in ability to recognize emotional states in others. The pathophysiology underlying the earliest manifestations of the disease is not fully understood; the objective of our study was to clarify this. We used functional magnetic resonance imaging to investigate changes in brain mechanisms of emotion recognition in pre-manifest carriers of the abnormal Huntington's disease gene (subjects with pre-manifest Huntington's disease): 16 subjects with pre-manifest Huntington's disease and 14 control subjects underwent 1.5 tesla magnetic resonance scanning while viewing pictures of facial expressions from the Ekman and Friesen series. Disgust, anger and happiness were chosen as emotions of interest. Disgust is the emotion in which recognition deficits have most commonly been detected in Huntington's disease; anger is the emotion in which impaired recognition was detected in the largest behavioural study of emotion recognition in pre-manifest Huntington's disease to date; and happiness is a positive emotion to contrast with disgust and anger. Ekman facial expressions were also used to quantify emotion recognition accuracy outside the scanner and structural magnetic resonance imaging with voxel-based morphometry was used to assess the relationship between emotion recognition accuracy and regional grey matter volume. Emotion processing in pre-manifest Huntington's disease was associated with reduced neural activity for all three emotions in partially separable functional networks. Furthermore, the Huntington's disease-associated modulation of disgust and happiness processing was negatively correlated with genetic markers of pre-manifest disease progression in distributed, largely extrastriatal networks. The modulated disgust network included insulae, cingulate cortices, pre- and postcentral gyri, precunei, cunei, bilateral putamena

  13. Quantum mechanics can reduce the complexity of classical models.

    PubMed

    Gu, Mile; Wiesner, Karoline; Rieper, Elisabeth; Vedral, Vlatko

    2012-03-27

    Mathematical models are an essential component of quantitative science. They generate predictions about the future, based on information available in the present. In the spirit of simpler is better; should two models make identical predictions, the one that requires less input is preferred. Yet, for almost all stochastic processes, even the provably optimal classical models waste information. The amount of input information they demand exceeds the amount of predictive information they output. Here we show how to systematically construct quantum models that break this classical bound, and that the system of minimal entropy that simulates such processes must necessarily feature quantum dynamics. This indicates that many observed phenomena could be significantly simpler than classically possible should quantum effects be involved.

  14. Mechanics of isolated extended bodies in classical field theories

    NASA Astrophysics Data System (ADS)

    Harte, Abraham Isaiah

    2007-08-01

    This thesis discusses a number of issues related to the description and motion of extended matter distributions in certain classical field theories. Particular emphasis is placed on general relativity and Maxwell theory, although many results also apply in related formalisms. They are obtained by extending and applying a series of ideas originally developed by W. G. Dixon to understand the mechanics of isolated bodies. Since this formalism is not well- known, we provide an extensive review in a unified form. This elucidates the structure of an object's stress-energy tensor and electromagnetic current vector. Multipole decompositions of these objects are also studied in considerable detail, and are designed to automatically "factor out" the relevant conservation laws. In the case of charge-current vectors, we show how to extend these results to also take into account the assumed smoothness and compactness of the physical matter. This allows essentially all reasonable current configurations with a given total charge to be parameterized without any reference to the spacetime structure. Such constructions provide natural methods for comparing the properties of current distributions in different systems. They also simplify the study of "rigid" currents. It is found that such objects cannot generally exist without allowing for the presence of singularities. An even stronger result applies to the nonexistence of rigid number density vectors in systems where the total number of particles is fixed. These formal developments are applied in various way to study the motions of various compact extended bodies. The first case considered here is that of an uncharged test mass embedded in a spatially-flat Friedmann-Robertson-Walker universe. It is shown that even with zero (global) momentum, such an object may adjust its mass and trajectory merely by changing shape. Mass shifts are in fact unavoidable in almost all cases, and could be significant for galactic superclusters. This

  15. Categorical quantum mechanics II: Classical-quantum interaction

    NASA Astrophysics Data System (ADS)

    Coecke, Bob; Kissinger, Aleks

    2016-08-01

    This is the second part of a three-part overview, in which we derive the category-theoretic backbone of quantum theory from a process ontology, treating quantum theory as a theory of systems, processes and their interactions. In this part, we focus on classical-quantum interaction. Classical and quantum systems are treated as distinct types, of which the respective behavioral properties are specified in terms of processes and their compositions. In particular, classicality is witnessed by ‘spiders’ which fuse together whenever they connect. We define mixedness and show that pure processes are extremal in the space of all processes, and we define entanglement and show that quantum theory indeed exhibits entanglement. We discuss the classification of tripartite qubit entanglement and show that both the GHZ-state and the W-state come from spider-like families of processes, which differ only in how they behave when they are connected by two or more wires. We define measurements and provide fully comprehensive descriptions of several quantum protocols involving classical data flow. Finally, we give a notion of ‘genuine quantumness’, from which special processes called ‘phase spiders’ arise, and get a first glimpse of quantum nonlocality.

  16. Interpreting nonlinear vibrational spectroscopy with the classical mechanical analogs of double-sided Feynman diagrams.

    PubMed

    Noid, W G; Loring, Roger F

    2004-10-15

    Observables in coherent, multiple-pulse infrared spectroscopy may be computed from a vibrational nonlinear response function. This response function is conventionally calculated quantum-mechanically, but the challenges in applying quantum mechanics to large, anharmonic systems motivate the examination of classical mechanical vibrational nonlinear response functions. We present an approximate formulation of the classical mechanical third-order vibrational response function for an anharmonic solute oscillator interacting with a harmonic solvent, which establishes a clear connection between classical and quantum mechanical treatments. This formalism permits the identification of the classical mechanical analog of the pure dephasing of a quantum mechanical degree of freedom, and suggests the construction of classical mechanical analogs of the double-sided Feynman diagrams of quantum mechanics, which are widely applied to nonlinear spectroscopy. Application of a rotating wave approximation permits the analytic extraction of signals obeying particular spatial phase matching conditions from a classical-mechanical response function. Calculations of the third-order response function for an anharmonic oscillator coupled to a harmonic solvent are compared to numerically correct classical mechanical results.

  17. An insight into the gastrointestinal component of fibromyalgia: clinical manifestations and potential underlying mechanisms.

    PubMed

    Slim, Mahmoud; Calandre, Elena Pita; Rico-Villademoros, Fernando

    2015-03-01

    Fibromyalgia syndrome is characterized by chronic generalized pain accompanied by a broad symptomatologic spectrum. Besides chronic fatigue, sleep disturbances, headaches and cognitive dysfunction that are extensively described in the literature, a considerable proportion of patients with fibromyalgia experience gastrointestinal symptoms that are commonly overlooked in the studies that are not specifically dedicated to evaluate these manifestations. Nevertheless, various attempts were undertaken to explore the gastrointestinal dimension of fibromyalgia. Several studies have demonstrated an elevated comorbidity of irritable bowel syndrome (IBS) among patients with fibromyalgia. Other studies have investigated the frequency of presentation of gastrointestinal symptoms in fibromyalgia in a nonspecific approach describing several gastrointestinal complaints frequently reported by these patients such as abdominal pain, dyspepsia and bowel changes, among others. Several underlying mechanisms that require further investigation could serve as potential explanatory hypotheses for the appearance of such manifestations. These include sensitivity to dietary constituents such as gluten, lactose or FODMAPs or alterations in the brain-gut axis as a result of small intestinal bacterial overgrowth or subclinical enteric infections such as giardiasis. The gastrointestinal component of fibromyalgia constitutes a relevant element of the multidisciplinary pathophysiologic mechanisms underlying fibromyalgia that need to be unveiled, as this would contribute to the adequate designation of relevant treatment alternatives corresponding to these manifestations.

  18. A Comparison of Kinetic Energy and Momentum in Special Relativity and Classical Mechanics

    ERIC Educational Resources Information Center

    Riggs, Peter J.

    2016-01-01

    Kinetic energy and momentum are indispensable dynamical quantities in both the special theory of relativity and in classical mechanics. Although momentum and kinetic energy are central to understanding dynamics, the differences between their relativistic and classical notions have not always received adequate treatment in undergraduate teaching.…

  19. [Classical dengue transmission dynamics involving mechanical control and prophylaxis].

    PubMed

    Toro-Zapata, Hernán D; Restrepo, Leonardo D; Vergaño-Salazar, Juan G; Muñoz-Loaiza, Aníbal

    2010-12-01

    Dengue fever transmission dynamics were studied in an endemic region considering the use of preventative measures and mechanical control in reducing transmission of the disease. A system of ordinary differential equations was proposed, describing the dynamics and their evolution as determined by numerical simulation. Different mechanical control and prophylaxis strategies were compared to the situation without control. The basic reproduction number R₀ was determined R₀ to show that if R₀ > 1 there would be a risk of an epidemic and otherwise the disease would have low impact levels. The basic reproduction number helps determine the dynamics' future pattern and contrast the results so obtained with those obtained numerically. It was concluded that although prophylaxis and mechanical control alone provide effective results in controlling the disease, if both controls are combined then infection levels become significantly reduced. Around 60 % mechanical control and prevention levels are needed to provide suitable results in controlling dengue outbreaks.

  20. Classical mechanics in non-commutative phase space

    NASA Astrophysics Data System (ADS)

    Wei, Gao-Feng; Long, Chao-Yun; Long, Zheng-Wen; Qin, Shui-Jie; Fu, Qiang

    2008-05-01

    In this paper the laws of motion of classical particles have been investigated in a non-commutative phase space. The corresponding non-commutative relations contain not only spatial non-commutativity but also momentum non-commutativity. First, new Poisson brackets have been defined in non-commutative phase space. They contain corrections due to the non-commutativity of coordinates and momenta. On the basis of this new Poisson brackets, a new modified second law of Newton has been obtained. For two cases, the free particle and the harmonic oscillator, the equations of motion are derived on basis of the modified second law of Newton and the linear transformation (Phys. Rev. D, 2005, 72: 025010). The consistency between both methods is demonstrated. It is shown that a free particle in commutative space is not a free particle with zero-acceleration in the non-commutative phase space, but it remains a free particle with zero-acceleration in non-commutative space if only the coordinates are non-commutative. Supported by National Natural Science Foundation of China (10347003, 60666001), Planned Training Excellent Scientific and Technological Youth Foundation of Guizhou Province, China (2002,2013), Science Foundation of Guizhou Province, China, and Creativity Foundation for Graduate Guizhou University, China (2006031)

  1. Laser-induced spatial symmetry breaking in quantum and classical mechanics.

    PubMed

    Franco, Ignacio; Brumer, Paul

    2006-07-28

    Phase-controllable transport in laser-irradiated spatially symmetric systems is shown to arise both quantum mechanically and classically from a common field-driven interference mechanism. Specifically, the quantum-to-classical transition for symmetry breaking in a quartic oscillator driven by an omega+2omega field is studied. For this, a double perturbation theory in the oscillator anharmonicity and external field strength, that admits an analytic classical limit, is carried out in the Heisenberg picture. The interferences responsible for the symmetry breaking are shown to survive in the classical limit and are the origins of classical control. Differences between reflection symmetry that plays a key role in the analysis, and parity that does not, are discussed.

  2. Entropic fluctuations in statistical mechanics: I. Classical dynamical systems

    NASA Astrophysics Data System (ADS)

    Jakšić, V.; Pillet, C.-A.; Rey-Bellet, L.

    2011-03-01

    Within the abstract framework of dynamical system theory we describe a general approach to the transient (or Evans-Searles) and steady state (or Gallavotti-Cohen) fluctuation theorems of non-equilibrium statistical mechanics. Our main objective is to display the minimal, model independent mathematical structure at work behind fluctuation theorems. In addition to its conceptual simplicity, another advantage of our approach is its natural extension to quantum statistical mechanics which will be presented in a companion paper. We shall discuss several examples including thermostated systems, open Hamiltonian systems, chaotic homeomorphisms of compact metric spaces and Anosov diffeomorphisms.

  3. Time Symmetric Quantum Mechanics and Causal Classical Physics ?

    NASA Astrophysics Data System (ADS)

    Bopp, Fritz W.

    2017-02-01

    A two boundary quantum mechanics without time ordered causal structure is advocated as consistent theory. The apparent causal structure of usual "near future" macroscopic phenomena is attributed to a cosmological asymmetry and to rules governing the transition between microscopic to macroscopic observations. Our interest is a heuristic understanding of the resulting macroscopic physics.

  4. Quantization in Classical Mechanics and Diffusion Mechanism of Alpha Decay, Proton and Cluster Radioactivity, Spontaneous Fission

    SciTech Connect

    Rusov, V. D.; Vlasenko, D. S.; Deliyergiyev, M. A.; Mavrodiev, S. Cht.

    2010-01-01

    Based on the Chetaev generalized theorem the Schroedinger equation as the stability condition of trajectories in classical dynamics in the presence of dissipative forces is derived. In the framework of this approach the alternative model for unified description of alpha decay, spontaneous fission, cluster and proton radioactivity and is developed. We show the possibility of the classical (without tunneling) description of radioactive decay of heavy nuclei, when the so called noise-induced transition or, in other words, the stochastic channel of radioactive decay conditioned by the Kramers diffusion mechanism is generated under certain conditions.Using the ENSDF nuclear data, we have found the parametrized solutions of the Kramers equation of the Langevin type by the Alexandrov dynamic auto-regularization method (REGN-Dubna program). These solutions describe with high-accuracy the dependences of half-life (the decay probability) of heavy radioactive nuclei on total kinetic energy of daughter decay products.Verification of the inverse problem solution in the framework of the universal Kramers description of alpha decay, spontaneous fission, cluster and proton radioactivity, which based on the newest experimental data for alpha-decay of even-even superheavy nuclei (Z = 114, 116, 118), shows good coincidence of the experimental and theoretical dependences of half-life on alpha-decay energy.

  5. From the attempt of certain classical reformulations of quantum mechanics to quasi-probability representations

    SciTech Connect

    Stulpe, Werner

    2014-01-15

    The concept of an injective affine embedding of the quantum states into a set of classical states, i.e., into the set of the probability measures on some measurable space, as well as its relation to statistically complete observables is revisited, and its limitation in view of a classical reformulation of the statistical scheme of quantum mechanics is discussed. In particular, on the basis of a theorem concerning a non-denseness property of a set of coexistent effects, it is shown that an injective classical embedding of the quantum states cannot be supplemented by an at least approximate classical description of the quantum mechanical effects. As an alternative approach, the concept of quasi-probability representations of quantum mechanics is considered.

  6. The Fourth Law of Motion in Classical Mechanics and Electrodynamics

    NASA Astrophysics Data System (ADS)

    Pinheiro, Mario J.

    2010-01-01

    Newton's second law has limited scope of application when transient phenomena are at stake. We endeavor here to consider a modification of Newton's second law in order to take into account sudden change (surge) of angular momentum or linear momentum. It is shown that space react back according to a kind of induction law that is related to inertia, but also appears to give evidence of a "fluidic" nature of space itself. The back-reaction is quantified by the time rate of the angular momentum flux threading a surface, mass dependent, and bearing similarity to the quantum mechanics phase shift, present in the Aharonov-Bohm and Aharonov-Casher effects, thus giving evidence of the property of vacuum polarization, a phenomena which is relative to local space. It is formulated a kind of (qualitative) Lenz law that gives an explanation to precession.

  7. Shaping mitotic chromosomes: From classical concepts to molecular mechanisms

    PubMed Central

    Kschonsak, Marc; Haering, Christian H

    2015-01-01

    How eukaryotic genomes are packaged into compact cylindrical chromosomes in preparation for cell divisions has remained one of the major unsolved questions of cell biology. Novel approaches to study the topology of DNA helices inside the nuclei of intact cells, paired with computational modeling and precise biomechanical measurements of isolated chromosomes, have advanced our understanding of mitotic chromosome architecture. In this Review Essay, we discuss – in light of these recent insights – the role of chromatin architecture and the functions and possible mechanisms of SMC protein complexes and other molecular machines in the formation of mitotic chromosomes. Based on the information available, we propose a stepwise model of mitotic chromosome condensation that envisions the sequential generation of intra-chromosomal linkages by condensin complexes in the context of cohesin-mediated inter-chromosomal linkages, assisted by topoisomerase II. The described scenario results in rod-shaped metaphase chromosomes ready for their segregation to the cell poles. PMID:25988527

  8. Moving Constraints as Stabilizing Controls in Classical Mechanics

    NASA Astrophysics Data System (ADS)

    Bressan, Alberto; Rampazzo, Franco

    2010-04-01

    The paper analyzes a Lagrangian system which is controlled by directly assigning some of the coordinates as functions of time, by means of frictionless constraints. In a natural system of coordinates, the equations of motion contain terms which are linear or quadratic with respect to time derivatives of the control functions. After reviewing the basic equations, we explain the significance of the quadratic terms related to geodesics orthogonal to a given foliation. We then study the problem of stabilization of the system to a given point by means of oscillating controls. This problem is first reduced to theweak stability for a related convex-valued differential inclusion, then studied by Lyapunov functions methods. In the last sections, we illustrate the results by means of various mechanical examples.

  9. Shaping mitotic chromosomes: From classical concepts to molecular mechanisms.

    PubMed

    Kschonsak, Marc; Haering, Christian H

    2015-07-01

    How eukaryotic genomes are packaged into compact cylindrical chromosomes in preparation for cell divisions has remained one of the major unsolved questions of cell biology. Novel approaches to study the topology of DNA helices inside the nuclei of intact cells, paired with computational modeling and precise biomechanical measurements of isolated chromosomes, have advanced our understanding of mitotic chromosome architecture. In this Review Essay, we discuss - in light of these recent insights - the role of chromatin architecture and the functions and possible mechanisms of SMC protein complexes and other molecular machines in the formation of mitotic chromosomes. Based on the information available, we propose a stepwise model of mitotic chromosome condensation that envisions the sequential generation of intra-chromosomal linkages by condensin complexes in the context of cohesin-mediated inter-chromosomal linkages, assisted by topoisomerase II. The described scenario results in rod-shaped metaphase chromosomes ready for their segregation to the cell poles.

  10. Stress: perceptions, manifestations, and coping mechanisms of student registered nurse anesthetists.

    PubMed

    Chipas, Anthony; Cordrey, Dan; Floyd, David; Grubbs, Lindsey; Miller, Sarah; Tyre, Brooks

    2012-08-01

    Stress is a response to change from the norm. Stress affects all individuals to varying degrees and can be positive, such as eustress, or negative, such as distress. The purpose of this qualitative, cross-sectional study was to investigate the stressors of the typical student registered nurse anesthetist (SRNA), with the objective of identifying trends in the perceptions, manifestations, and coping mechanisms of stress. An online (SurveyMonkey) questionnaire composed of 54 study-specific questions was developed to assess stress in the SRNA population. The questionnaire was sent to members of the American Association of Nurse Anesthetists via email invitation. The study yielded a sample of 1,282 SRNA participants. Analysis revealed statistically significant relationships between self-reported stress and negative outcomes, such as increased sick days, decreased health and wellness, and depression. The study demonstrated that SRNAs perceive their stress as above average, and it remains a central concern for them.

  11. Quantum versus classical foundation of statistical mechanics under experimentally realistic conditions.

    PubMed

    Reimann, Peter; Evstigneev, Mykhaylo

    2013-11-01

    Focusing on isolated macroscopic systems, described in terms of either a quantum mechanical or a classical model, our two key questions are how far does an initial ensemble (usually far from equilibrium and largely unknown in detail) evolve towards a stationary long-time behavior (equilibration) and how far is this steady state in agreement with the microcanonical ensemble as predicted by statistical mechanics (thermalization). A recently developed quantum mechanical treatment of the problem is briefly summarized, putting particular emphasis on the realistic modeling of experimental measurements and nonequilibrium initial conditions. Within this framework, equilibration can be proven under very weak assumptions about those measurements and initial conditions, while thermalization still requires quite strong additional hypotheses. An analogous approach within the framework of classical mechanics is developed and compared with the quantum case. In particular, the assumptions to guarantee classical equilibration are now rather strong, while thermalization then follows under relatively weak additional conditions.

  12. Two-Time Green's Functions and the Spectral Density Method in Nonextensive Classical Statistical Mechanics

    NASA Astrophysics Data System (ADS)

    Cavallo, A.; Cosenza, F.; de Cesare, L.

    2001-12-01

    The two-time retarded and advanced Green's function technique is formulated in nonextensive classical statistical mechanics within the optimal Lagrange multiplier framework. The main spectral properties are presented and a spectral decomposition for the spectral density is obtained. Finally, the nonextensive version of the spectral density method is given and its effectiveness is tested by exploring the equilibrium properties of a classical ferromagnetic spin chain.

  13. The calculation of the thermal rate coefficient by a method combining classical and quantum mechanics

    NASA Astrophysics Data System (ADS)

    Wahnström, Göran; Carmeli, Benny; Metiu, Horia

    1988-02-01

    We propose and test a method for computing flux-flux correlation functions (and thermal rate coefficients) which divides the degrees of freedom in two groups, one treated classically and the other quantum mechanically. The method is tested by applying it to a simple model for which we can also obtain exact results. The approximate method gives good results if the mass associated with the classical degrees of freedom exceeds 16 a.u.

  14. Ground-state properties of the retinal molecule: from quantum mechanical to classical mechanical computations of retinal proteins

    SciTech Connect

    Suhai, Sandor

    2011-01-01

    Retinal proteins are excellent systems for understanding essential physiological processes such as signal transduction and ion pumping. Although the conjugated polyene system of the retinal chromophore is best described with quantum mechanics, simulations of the long-timescale dynamics of a retinal protein in its physiological, flexible, lipid-membrane environment can only be performed at the classical mechanical level. Torsional energy barriers are a critical ingredient of the classical force-field parameters. Here we review briefly current retinal force fields and discuss new quantum mechanical computations to assess how the retinal Schiff base model and the approach used to derive the force-field parameters may influence the torsional potentials.

  15. Pulmonary edema following scorpion envenomation: mechanisms, clinical manifestations, diagnosis and treatment.

    PubMed

    Bahloul, Mabrouk; Chaari, Anis; Dammak, Hassen; Samet, Mohamed; Chtara, Kamilia; Chelly, Hedi; Ben Hamida, Chokri; Kallel, Hatem; Bouaziz, Mounir

    2013-01-10

    Scorpion envenomation is common in tropical and subtropical regions. Cardio-respiratory manifestations, mainly cardiogenic shock and pulmonary edema, are the leading causes of death after scorpion envenomation. The mechanism of pulmonary edema remains unclear and contradictory conclusions were published. However, most publications confirm that pulmonary edema has been attributed to acute left ventricular failure. Cardiac failure can result from massive release of catecholamines, myocardial damage induced by the venom or myocardial ischemia. Factors usually associated with the diagnosis of pulmonary edema were young age, tachypnea, agitation, sweating, or the presence of high plasma protein concentrations. Treatment of scorpion envenomation has two components: antivenom administration and supportive care. The latter mainly targets hemodynamic impairment and cardiogenic pulmonary edema. In Latin America, and India, the use of Prazosin is recommended for treatment of pulmonary edema because pulmonary edema is associated with arterial hypertension. However, in North Africa, scorpion leads to cardiac failure with systolic dysfunction with normal vascular resistance and dobutamine was recommended. Dobutamine infusion should be used as soon as we have enough evidence suggesting the presence of pulmonary edema, since it has been demonstrated that scorpion envenomation can result in pulmonary edema secondary to acute left ventricular failure. In severe cases, mechanical ventilation can be required.

  16. Classical Yang-Mills Mechanics: Instant vs. Light-cone Form

    SciTech Connect

    Mladenov, D.

    2010-11-25

    Two different forms of relativistic dynamics, the instant and the light-cone form, for the pure SU(2) Yang-Mills field theory in 4-dimensional Minkowski space are examined under the supposition that the gauge fields depend on the time evolution parameter only. The obtained under that restriction of gauge potential space homogeneity mechanical matrix model, sometimes called Yang-Mills classical mechanics, is systematically studied in its instant and light-cone form of dynamics using the Dirac's generalized Hamiltonian approach. In the both cases the constraint content of the obtained mechanical systems is found. In contrast to its well-known instant-time counterpart the light-cone version of SU(2) Yang-Mills classical mechanics has in addition to the constraints generating the SU(2) gauge transformations the new first and second class constraints also. On account of all of these constraints a complete reduction in number of the degrees of freedom is performed. In the instant form of dynamics it is shown that after elimination of the gauge degrees of freedom from the classical SU(2) Yang-Mills mechanics the resulting unconstrained system represents the ID{sub 3} Euler-Calogero-Moser model with a certain external fourth-order potential, whereas in the light-cone form it is argued that the classical evolution of the unconstrained degrees of freedom is equivalent to a free one-dimensional particle dynamics.

  17. The Development of Effective Classical Potentials and the Quantum Statistical Mechanical Second Virial Coefficient of Water

    SciTech Connect

    Schenter, Gregory K.

    2002-10-08

    The second virial coefficient of water is calculated at low temperature by considering full quantum statistical mechanical effects. At low enough temperatures experimental results are limited and molecular models can be used for accurate extrapolation. In doing so, one must separate inaccuracies of the intermolecular potential from limitations of simulation such as the neglect of higher-order quantum corrections. Effective classical potentials may be used to understand the limitations of classical simulation. In this work we calculate the exact quantum statistical mechanical second virial coefficient and find that using a simple form for the effective classical potential introduced by Miller we are able to reproduce the exact quantum statistical results. This approach provides a significant improvement to conventional first order expansions of the second virial coefficient.

  18. Quantum epistemology from subquantum ontology: Quantum mechanics from theory of classical random fields

    NASA Astrophysics Data System (ADS)

    Khrennikov, Andrei

    2017-02-01

    The scientific methodology based on two descriptive levels, ontic (reality as it is) and epistemic (observational), is briefly presented. Following Schrödinger, we point to the possible gap between these two descriptions. Our main aim is to show that, although ontic entities may be unaccessible for observations, they can be useful for clarification of the physical nature of operational epistemic entities. We illustrate this thesis by the concrete example: starting with the concrete ontic model preceding quantum mechanics (the latter is treated as an epistemic model), namely, prequantum classical statistical field theory (PCSFT), we propose the natural physical interpretation for the basic quantum mechanical entity-the quantum state ("wave function"). The correspondence PCSFT ↦ QM is not straightforward, it couples the covariance operators of classical (prequantum) random fields with the quantum density operators. We use this correspondence to clarify the physical meaning of the pure quantum state and the superposition principle-by using the formalism of classical field correlations.

  19. Wave-like variables of a classical particle and their connections to quantum mechanics

    NASA Astrophysics Data System (ADS)

    Yang, Chen

    2017-01-01

    In many texts, the transition from classical mechanics to quantum mechanics is achieved by substituting the action for the phase angle. The paper presents a different approach to show some connections between classical and quantum mechanics for a single particle for an audience at graduate and postgraduate levels. Firstly, it is shown that a wave equation of action can be derived under the free particle condition and the Legendre transform. The wave-like solutions of the action, Hamiltonian and momentum of the free particle are presented. Using the discrete approximation, the equation of motion of a single particle, in scalar potential field, is obtained in a similar form to Schrödinger’s equation. The rest of the paper discusses the propagation, superposition of the wave-like dynamic variables and their connections to quantum mechanics. The superposition of the variables of a particle is generally distinct from the superposition of classical waves (e.g. acoustics). The quantum superposition provides a self-consistent interpretation of the wave-like solutions of the variables. Connections between the classical and quantum relations for corresponding variables are observed from the one-to-one comparisons.

  20. Feeding Behavior of Aplysia: A Model System for Comparing Cellular Mechanisms of Classical and Operant Conditioning

    ERIC Educational Resources Information Center

    Baxter, Douglas A.; Byrne, John H.

    2006-01-01

    Feeding behavior of Aplysia provides an excellent model system for analyzing and comparing mechanisms underlying appetitive classical conditioning and reward operant conditioning. Behavioral protocols have been developed for both forms of associative learning, both of which increase the occurrence of biting following training. Because the neural…

  1. Quantum mechanics vs local realism near the classical limit:A Bell inequality for spin s

    SciTech Connect

    Mermin, N.D.

    1980-07-15

    The quantitative quantum-mechanical analysis of the Einstein-Podolsky-Rosen experiment for correlated particles of arbitrary spin s is shown to contradict a generalized form of Bell's inequality, for suitable orientations of the detectors. As the classical (s ..-->.. infinity ) limit is approached, the range of angles for which the contradiction arises vanishes as 1/s.

  2. Examining the Construction Process: A Study of Changes in Level 10 Students' Understanding of Classical Mechanics.

    ERIC Educational Resources Information Center

    Shymansky, James A.; And Others

    1997-01-01

    Explores students' conceptual understanding and conceptual growth in classical mechanics in the natural context of a grade 10 science classroom. Findings indicate that students' knowledge structures remained stable across the 10 weeks and remained unchanged 4 weeks after instruction ceased. Contains 30 references. (Author/JRH)

  3. Application of Hamilton's Principle to the Study of the Anharmonic Oscillator in Classical Mechanics.

    ERIC Educational Resources Information Center

    And Others; Gilmartin, Harvey

    1979-01-01

    Presented is a form of Hamilton's principle for classical mechanics appropriate to the study of arbitrary self-sustained vibrations in one dimension. It is applied as an approximate computational tool to the study of several examples of anharmonic oscillation. (Author/GA)

  4. Quantum to classical transition of inflationary perturbations: Continuous spontaneous localization as a possible mechanism

    NASA Astrophysics Data System (ADS)

    Das, Suratna; Lochan, Kinjalk; Sahu, Satyabrata; Singh, T. P.

    2013-10-01

    The inflationary paradigm provides a mechanism to generate the primordial perturbations needed to explain the observed large-scale structures in the Universe. Inflation traces back all the inhomogeneities to quantum fluctuations although the structures look classical today. The squeezing of primordial quantum fluctuations along with the mechanism of decoherence accounts for many aspects of this quantum-to-classical transition, although it remains a matter of debate as to whether this is sufficient to explain the issue of the realization of a single outcome (i.e. the issue of macro-objectification) from a quantum ensemble given that the Universe is a closed system. A similar question of the emergence of classical behavior of macroscopic objects exists also for laboratory systems and apart from decoherence there have been attempts to resolve this issue through continuous spontaneous localization (CSL), which is a stochastic nonlinear modification of the nonrelativistic Schrödinger equation. Recently, Martin et al. have investigated whether a CSL-like mechanism with a constant strength parameter—when the Mukhanov-Sasaki variable is taken as the “collapse operator”—can explain how the primordial quantum perturbations generated during inflation become classical. Within the scope of their assumptions they essentially come to a negative conclusion. In the present work, we generalize their analysis by allowing the CSL strength parameter to depend on physical scales so as to capture the CSL amplification mechanism. We show that such a generalization provides a mechanism for the macro-objectification (i.e. classicalization) of the inflationary quantum perturbations, while also preserving the scale invariance of the power spectrum and the phase coherence of superhorizon perturbation modes in a particular class of these models.

  5. Quantum vs Classical Mechanics for a 'Simple' Dissociation Reaction. Should They Give the Same Results?

    NASA Astrophysics Data System (ADS)

    Holloway, Stephen

    1997-03-01

    When performing molecular dynamical simulations on light systems at low energies, there is always the risk of producing data that bear no similarity to experiment. Indeed, John Barker himself was particularly anxious about treating Ar scattering from surfaces using classical mechanics where it had been shown experimentally in his own lab that diffraction occurs. In such cases, the correct procedure is probably to play the trump card "... well of course, quantum effects will modify this so that....." and retire gracefully. For our particular interests, the tables are turned in that we are interested in gas-surface dynamical studies for highly quantized systems, but would be interested to know when it is possible to use classical mechanics in order that a greater dimensionality might be treated. For molecular dissociation and scattering, it has been oft quoted that the greater the number of degrees of freedom, the more appropriate is classical mechanics, primarily because of the mass averaging over the quantized dimensions. Is this true? We have been investigating the dissociation of hydrogen molecules at surfaces and in this talk I will present quantum results for dissociation and scattering, along with a novel method for their interpretation based upon adiabatic potential energy surfaces. Comparison with classical calculations will be made and conclusions drawn. a novel method for their interpretation based upon adiabatic potential energy surfaces

  6. The study of the mechanisms of the different phenotypical manifestations in patients with reciprocal translocations

    NASA Astrophysics Data System (ADS)

    Lozynskyi, Rostyslav; Lozynska, Maria

    2006-04-01

    Cytogenetical study of lymphocytes using the light microscopy could reveal a large amount of chromosomal abnormalities, which determine corresponding hereditary disorders. However, geneticists sometimes observe the cases where the same chromosomal rearrangements seen in light microscope cause quite different phenotype (from normal to abnormal) in relatives. The aim of the study was to explain the mechanisms of the different phenotype appearance in family members carrying the same reciprocal translocations. It was carried out the standard chromosome analysis in 12 families, where some relatives had reciprocal translocations. Chromosomes were differentially stained using G-method. The samples were analysed in optical microscope (x1000). Using OMIM gene map, UCSC Genome Browser, eGenome Release v2.3 and Unigene databases it was revealed transposons and transposon derivates in chromosome regions involved in translocations. We suppose that the variability of clinical manifestations in translocation-bearing patient is caused by the influence of the transposons, such as Hsmar2, Alu-elements or some others. We propose the following mechanisms of transposone action in these patients. The first may lie on recombination between the 2 specific DNA-transposon containing sites on different chromosomes resulting in balanced reciprocal translocation with no significant influence on the most genes' activity in corresponding regions. The weakening of transposase repression, which may follow in gametes, increases the transposase activity, and hereby, the probability of transposon dislocation. Dislocation can change the activity of groups of genes, because transposons often carry the regulatory sequences. This can induce multiply innate disorders in the progeny of the phenotypically healthy parents, carrying the translocation. According to the second mechanism, the reciprocal translocation is caused by recombination between 2 Alu repeats. These repeats can undergo reverse

  7. Molecular Mimicry between Chikungunya Virus and Host Components: A Possible Mechanism for the Arthritic Manifestations

    PubMed Central

    Reddy, Vijayalakshmi; Desai, Anita; Krishna, Shankar Susarla; Vasanthapuram, Ravi

    2017-01-01

    Background Chikungunya virus (CHIKV), a reemerging pathogen causes a self limited illness characterized by fever, headache, myalgia and arthralgia. However, 10–20% affected individuals develop persistent arthralgia which contributes to considerable morbidity. The exact molecular mechanisms underlying these manifestations are not well understood. The present study investigated the possible occurrence of molecular mimicry between CHIKV E1 glycoprotein and host human components. Methodology Bioinformatic tools were used to identify peptides of CHIKV E1 exhibiting similarity to host components. Two peptides (A&B) were identified using several bioinformatic tools, synthesised and used to validate the results obtained in silico. An ELISA was designed to assess the immunoreactivity of serum samples from CHIKV patients to these peptides. Further, experiments were conducted in a C57BL/6J experimental mouse model to investigate if peptide A and peptide B were indeed capable of inducing pathology. Findings The serum samples showed reactivity of varying degrees, indicating that these peptides are indeed being recognized by the host immune system during CHIKV infection. Further, these peptides when injected into C57BL/6J mice were able to induce significant inflammation in the muscles of C57BL/6J mice, similar to that observed in animals that were injected with CHIKV alone. Additionally, animals that were primed initially with CHIKV followed by a subsequent injection of the CHIKV peptides exhibited enhanced inflammatory pathology in the skeletal muscles as compared to animals that were injected with peptides or virus alone. Collectively these observations validate the hypothesis that molecular mimicry between CHIKV E1 protein and host proteins does contribute to pathology in CHIKV infection. PMID:28125580

  8. Classical limits of quantum mechanics on a non-commutative configuration space

    SciTech Connect

    Benatti, Fabio; Gouba, Laure

    2013-06-15

    We consider a model of non-commutative quantum mechanics given by two harmonic oscillators over a non-commutative two dimensional configuration space. We study possible ways of removing the non-commutativity based on the classical limit context known as anti-Wick quantization. We show that removal of non-commutativity from the configuration space and from the canonical operators is not commuting operation.

  9. Structure and Binding Mechanism of Vascular Endothelial Cadherin: A Divergent Classical Cadherin

    SciTech Connect

    J Brasch; O Harrison; G Ahlsen; S Carnally; R Henderson; B Honig; L Shapiro

    2011-12-31

    Vascular endothelial cadherin (VE-cadherin), a divergent member of the type II classical cadherin family of cell adhesion proteins, mediates homophilic adhesion in the vascular endothelium. Previous investigations with a bacterially produced protein suggested that VE-cadherin forms cell surface trimers that bind between apposed cells to form hexamers. Here we report studies of mammalian-produced VE-cadherin ectodomains suggesting that, like other classical cadherins, VE-cadherin forms adhesive trans dimers between monomers located on opposing cell surfaces. Trimerization of the bacterially produced protein appears to be an artifact that arises from a lack of glycosylation. We also present the 2.1-{angstrom}-resolution crystal structure of the VE-cadherin EC1-2 adhesive region, which reveals homodimerization via the strand-swap mechanism common to classical cadherins. In common with type II cadherins, strand-swap binding involves two tryptophan anchor residues, but the adhesive interface resembles type I cadherins in that VE-cadherin does not form a large nonswapped hydrophobic surface. Thus, VE-cadherin is an outlier among classical cadherins, with characteristics of both type I and type II subfamilies.

  10. On the antioxidant mechanism of curcumin: classical methods are needed to determine antioxidant mechanism and activity.

    PubMed

    Barclay, L R; Vinqvist, M R; Mukai, K; Goto, H; Hashimoto, Y; Tokunaga, A; Uno, H

    2000-09-07

    [reaction: see structure] The antioxidant activity of curcumin (1, 7-bis(4-hydroxy-3-methoxyphenyl)-1,6-heptadiene-3,5-dione) was determined by inhibition of controlled initiation of styrene oxidation. Synthetic nonphenolic curcuminoids exhibited no antioxidant activity; therefore, curcumin is a classical phenolic chain-breaking antioxidant, donating H atoms from the phenolic groups not the CH(2) group as has been suggested (Jovanovic et al. J. Am. Chem. Soc. 1999, 121, 9677). The antioxidant activities of o-methoxyphenols are decreased in hydrogen bond accepting media.

  11. The role of quantum-mechanical interference and quasi-classical effects in conjugated hydrocarbons.

    PubMed

    Fantuzzi, Felipe; Cardozo, Thiago Messias; Nascimento, Marco Antonio Chaer

    2012-04-28

    The nature of the chemical bond in conjugated hydrocarbons is analyzed through the generalized product function energy partitioning (GPF-EP) method, which allows the calculation of the quantum-mechanical interference and quasi-classical contributions to the energy. The method is applied to investigate the differences between the chemical bonding in conjugated and non-conjugated hydrocarbon isomers and to evaluate the contribution from the energy components to the stabilization of the molecules. It is shown that in all cases quantum-mechanical interference has the effect of concentrating π electron density between the two carbon atoms directly involved in the (C-C)π bonds. For the conjugated isomers, this effect is accompanied by a substantial reduction of electron density in the π space of the neighbouring (C-C)σ bond. On the other hand, quasi-classical effects are shown to be responsible for the extra stabilization of the conjugated isomers, in which a decrease of the π space kinetic reference energy seems to play an important role. Finally, it is shown that the polarization of p-like orbitals in compounds with alternating single and double bonds ultimately increases electron density in the π space of the neighbouring (C-C)σ bond. Therefore, quasi-classical effects, rather than covalent ones, seem to be responsible for several properties of conjugated molecules, such as thermodynamic stability, planarity and (C-C)σ bond shortening. The shortcomings of the delocalization concept are discussed.

  12. Magnetic monopoles and dyons revisited: a useful contribution to the study of classical mechanics

    NASA Astrophysics Data System (ADS)

    dos Santos, Renato P.

    2015-05-01

    Graduate-level physics curricula in many countries around the world, as well as senior-level undergraduate ones in some major institutions, include classical mechanics courses, mostly based on Goldstein’s textbook masterpiece. During the discussion of central force motion, however, the Kepler problem is virtually the only serious application presented. In this paper, we present another problem that is also soluble, namely the interaction of Schwinger’s dual-charged (dyon) particles. While the electromagnetic interaction of magnetic monopoles and electric charges was studied in detail some 40 years ago, we consider that a pedagogical discussion of it from an essentially classical mechanics point of view is a useful contribution for students. Following a path that generalizes Kepler’s problem and Rutherford scattering, we show that they exhibit remarkable properties such as stable non-planar orbits, as well as rainbow and glory scattering, which are not present in the ordinary scattering of two singly charged particles. Moreover, it can be extended further to the relativistic case and to a semi-classical quantization, which can also be included in the class discussion.

  13. ForceFit: a code to fit classical force fields to quantum mechanical potential energy surfaces.

    PubMed

    Waldher, Benjamin; Kuta, Jadwiga; Chen, Samuel; Henson, Neil; Clark, Aurora E

    2010-09-01

    The ForceFit program package has been developed for fitting classical force field parameters based upon a force matching algorithm to quantum mechanical gradients of configurations that span the potential energy surface of the system. The program, which runs under UNIX and is written in C++, is an easy-to-use, nonproprietary platform that enables gradient fitting of a wide variety of functional force field forms to quantum mechanical information obtained from an array of common electronic structure codes. All aspects of the fitting process are run from a graphical user interface, from the parsing of quantum mechanical data, assembling of a potential energy surface database, setting the force field, and variables to be optimized, choosing a molecular mechanics code for comparison to the reference data, and finally, the initiation of a least squares minimization algorithm. Furthermore, the code is based on a modular templated code design that enables the facile addition of new functionality to the program.

  14. Bosonic seesaw mechanism in a classically conformal extension of the Standard Model

    NASA Astrophysics Data System (ADS)

    Haba, Naoyuki; Ishida, Hiroyuki; Okada, Nobuchika; Yamaguchi, Yuya

    2016-03-01

    We suggest the so-called bosonic seesaw mechanism in the context of a classically conformal U(1) B - L extension of the Standard Model with two Higgs doublet fields. The U(1) B - L symmetry is radiatively broken via the Coleman-Weinberg mechanism, which also generates the mass terms for the two Higgs doublets through quartic Higgs couplings. Their masses are all positive but, nevertheless, the electroweak symmetry breaking is realized by the bosonic seesaw mechanism. Analyzing the renormalization group evolutions for all model couplings, we find that a large hierarchy among the quartic Higgs couplings, which is crucial for the bosonic seesaw mechanism to work, is dramatically reduced toward high energies. Therefore, the bosonic seesaw is naturally realized with only a mild hierarchy, if some fundamental theory, which provides the origin of the classically conformal invariance, completes our model at some high energy, for example, the Planck scale. We identify the regions of model parameters which satisfy the perturbativity of the running couplings and the electroweak vacuum stability as well as the naturalness of the electroweak scale.

  15. Juvenile Huntington's disease: does a dosage-effect pathogenic mechanism differ from the classical adult disease?

    PubMed

    Squitieri, Ferdinando; Frati, Luigi; Ciarmiello, Andrea; Lastoria, Secondo; Quarrell, Oliver

    2006-02-01

    Huntington's disease (HD) is caused by a CAG repeat mutation translating as a polyglutamine (poly(Q)) expansion in the huntingtin protein, whose main pathogenic mechanism is a gain of toxic function. In the case of large expansions beyond 60 repeats onset may result in juvenile HD (JHD, onset before 20 years of age). However, the triplet number does not represent the only onset modifier even in case of large expansions, mechanisms other than the size of the mutation contribute to the phenotype. In this review we discuss the possibility that some of the pathogenic mechanisms contributing to age at onset and progression may differ in the early onset HD compared with the classical adult pathology.

  16. Nucleation theorems, the statistical mechanics of molecular clusters, and a revision of classical nucleation theory

    NASA Astrophysics Data System (ADS)

    Ford, I. J.

    1997-11-01

    The nucleation theorems relate the temperature and supersaturation dependence of the rate of nucleation of droplets from a metastable vapor phase to properties of the critical molecular cluster, the size that is approximately equally likely to grow or decay. They are derived here using a combination of statistical mechanics and cluster population dynamics, using an arbitrary model cluster definition. The theorems are employed to test the validity of the classical theory of homogeneous nucleation and its ``internally consistent'' form. It is found that the properties of the critical cluster for these models are incorrect, and it emerges that this occurs because the classical theory employs the free energy of a fixed droplet, rather than one free to take any position in space. Thus a term representing positional, or mixing, entropy is missing from the cluster free energy. A revised model is proposed, based on the capillarity approximation but with such a term included, and it is shown that it is fully consistent with the nucleation theorems. The model increases classical rates by factors of approximately 104-106. Other nucleation models should be tested for internal consistency using the same methods. Finally, the nucleation theorems are used to extract the excess internal energies of molecular clusters from experimental data for several substances.

  17. Is classical mechanics a prerequisite for learning physics of the 20th century?

    NASA Astrophysics Data System (ADS)

    Walwema, Godfrey B.; French, Debbie A.; Verley, Jim D.; Burrows, Andrea C.

    2016-11-01

    Physics of the 20th century has contributed significantly to modern technology, and yet many physics students are never availed the opportunity to study it as part of the curriculum. One of the possible reasons why it is not taught in high school and introductory physics courses could be because curriculum designers believe that students need a solid background in classical mechanics and calculus in order to study physics of the 20th century such as the photoelectric effect, special and general relativity, the uncertainty principle, etc. This presumption may not be justifiable or valid. The authors of this paper contend that teaching physics of the 20th century aids students in relating physics to modern technology and the real world, making studying physics exciting. In this study, the authors correlated scores for matched questions in the Mechanics Baseline Test and a physics of the 20th century test in order to examine the trend of the scores. The participants included undergraduate students attending an introductory algebra-based physics course with no intention of taking physics at a higher level. The analysis of the scores showed no significant correlation for any of the matched pairs of questions. The purpose of this article is to recommend that even without a solid background in classical mechanics, teachers can introduce physics of the 20th century to their students for increased interest.

  18. Non-classical correlations between single photons and phonons from a mechanical oscillator

    NASA Astrophysics Data System (ADS)

    Riedinger, Ralf; Hong, Sungkun; Norte, Richard A.; Slater, Joshua A.; Shang, Juying; Krause, Alexander G.; Anant, Vikas; Aspelmeyer, Markus; Gröblacher, Simon

    2016-02-01

    Interfacing a single photon with another quantum system is a key capability in modern quantum information science. It allows quantum states of matter, such as spin states of atoms, atomic ensembles or solids, to be prepared and manipulated by photon counting and, in particular, to be distributed over long distances. Such light-matter interfaces have become crucial to fundamental tests of quantum physics and realizations of quantum networks. Here we report non-classical correlations between single photons and phonons—the quanta of mechanical motion—from a nanomechanical resonator. We implement a full quantum protocol involving initialization of the resonator in its quantum ground state of motion and subsequent generation and read-out of correlated photon-phonon pairs. The observed violation of a Cauchy-Schwarz inequality is clear evidence for the non-classical nature of the mechanical state generated. Our results demonstrate the availability of on-chip solid-state mechanical resonators as light-matter quantum interfaces. The performance we achieved will enable studies of macroscopic quantum phenomena as well as applications in quantum communication, as quantum memories and as quantum transducers.

  19. Issues and progress in transforming a middle-division classical mechanics/math methods course

    NASA Astrophysics Data System (ADS)

    Pollock, Steven J.; Pepper, Rachel E.; Marino, Alysia D.

    2012-02-01

    The physics department at the University of Colorado, Boulder has recently begun the transformation of its Classical Mechanics/Math Methods course, a middle-division course taken primarily by sophomore physics majors. We discuss the process of course transformation, including holding faculty meetings to create consensus learning goals and a conceptual diagnostic, and adopting, adapting and creating course materials and structures. We also report preliminary observations of student learning gains, student attitudes towards the transformation, and common student difficulties with the course material. We also discuss ongoing plans for the course transformation.

  20. Spectroscopic studies of the classical Cepheid ζ Gem: Analysis of the velocity field in the atmosphere and manifestation of the presence of a circumstellar envelope

    NASA Astrophysics Data System (ADS)

    Usenko, I. A.

    2016-06-01

    Based on five high-resolution spectra in the range 5625-7525 ˚A taken in 1995 and covering the ascending branch of the light curve from minimum to maximum, we have performed spectroscopic studies of the classical Cepheid ζ Gem. The atmospheric parameters and chemical composition of the Cepheid have been refined. The abundances of the key elements of the evolution of yellow supergiants are typical for an object that has passed the first dredge-up: a C underabundance, N, Na, and Al overabundances, and nearly solar O and Mg abundances. We have estimated [Fe/H] = +0.01 dex; the abundances of the remaining elements are also nearly solar. The metal absorption lines in all spectra show a clear asymmetry and the formation of secondary blue (B1 and B2) and red (R1 and R2) components, just as for the Cepheid X Sgr. The Hα absorption line is also split into blue (B) and red (R) components with different depths changing with pulsation phase. To analyze the velocity field in the atmosphere of ζ Gem, we have estimated the radial velocities from specially selected (with clear signatures of the B1, B2, R1, and R2 components) absorption lines (neutral atoms and ions) of metals (38 lines) and the B and R components of the Hα line. Analysis of these estimates has shown that their scatter is from -22 to 36 km s-1 for all pulsation phases but does not exceed 35-40 km s-1 for each individual phase, while it does not exceed 22 km s-1 for the Hα line components. The radial velocity estimates for the metal lines and their B1 and B2 components have been found to depend on the depths, suggesting the presence of a velocity gradient in the atmosphere. No significant difference in velocities between the atoms and ions of the metal lines is observed, i.e., there is no significant inhomogeneity in the upper atmospheric layers of the Cepheid. Since the averaged radial velocity estimates for the cores of the metal lines and their B1 and B2 components change with pulsation phase and coincide

  1. Use of the poincare sphere in polarization optics and classical and quantum mechanics. Review

    NASA Astrophysics Data System (ADS)

    Malykin, G. B.

    1997-03-01

    The method of the Poincaré sphere, which was proposed by Henri Poincaré in 1891-1892, is a convenient approach to represent polarized light. This method is graphical: each point on the sphere corresponds to a certain polarization state. Apart from the obvious representation of polarized light, the method of the Poincaré sphere permits efficient solution of problems that result from the use of a set of phase plates or a combination of phase plates and ideally homogeneous polarizers. Recently, to calculate the geometric phase (which is often called the Berry phase) in polarization optics and quantum and classical mechanics, the method of the Poincaré sphere has drawn much attention, since it allows us to carry out these calculations very efficiently and intuitively using the solid angle resting, on a closed curve on the Poincaré sphere that corresponds to the change in the state of light polarization or in the state of spin of an elementary particle or its orientation in space from the viewpoint of systems in classical mechanics. The review considers papers on the above problems.

  2. Quantum statistics and classical mechanics: real time correlation functions from ring polymer molecular dynamics.

    PubMed

    Craig, Ian R; Manolopoulos, David E

    2004-08-22

    We propose an approximate method for calculating Kubo-transformed real-time correlation functions involving position-dependent operators, based on path integral (Parrinello-Rahman) molecular dynamics. The method gives the exact quantum mechanical correlation function at time zero, exactly satisfies the quantum mechanical detailed balance condition, and for correlation functions of the form C(Ax)(t) and C(xB)(t) it gives the exact result for a harmonic potential. It also works reasonably well at short times for more general potentials and correlation functions, as we illustrate with some example calculations. The method provides a consistent improvement over purely classical molecular dynamics that is most apparent in the low-temperature regime.

  3. Quantization in classical mechanics and its relation to the Bohmian {Psi}-field

    SciTech Connect

    Rusov, V.D.; Vlasenko, D.S.; Mavrodiev, S.Cht.

    2011-08-15

    Research highlights: > The Schroedinger equation is derived from the classical Hamiltonian mechanics. > This derivation is based on the Chetaev theorem on stable dynamical trajectories. > The conditions for correctness of trajectory quantum mechanics are discussed. - Abstract: Based on the Chetaev theorem on stable dynamical trajectories in the presence of dissipative forces, we obtain the generalized condition for stability of Hamilton systems in the form of the Schroedinger equation. It is shown that the energy of dissipative forces, which generate the Chetaev generalized condition of stability, coincides exactly with the Bohm 'quantum' potential. Within the frame-work of Bohmian quantum mechanics supplemented by the generalized Chetaev theorem and on the basis of the principle of least action for dissipative forces, we show that the squared amplitude of a wave function in the Schroedinger equation is equivalent semantically and syntactically to the probability density function for the number of particle trajectories, relative to which the velocity and the position of the particle are not hidden parameters. The conditions for the correctness of trajectory interpretation of quantum mechanics are discussed.

  4. Exploring Synergy between Classic Mutagens and Antibiotics To Examine Mechanisms of Synergy and Antibiotic Action.

    PubMed

    Song, Lisa Yun; D'Souza, Sara; Lam, Karen; Kang, Tina Manzhu; Yeh, Pamela; Miller, Jeffrey H

    2015-12-28

    We used classical mutagens in Gram-negative Escherichia coli to study synergies with different classes of antibiotics, test models of antibiotic mechanisms of action, and examine the basis of synergy. We used 4-nitroquinoline 1-oxide (4NQO), zebularine (ZEB), 5-azacytidine (5AZ), 2-aminopurine (2AP), and 5-bromodeoxyuridine (5BrdU) as mutagens (with bactericidal potency of 4NQO > ZEB > 5AZ > 2AP > 5BrdU) and vancomycin (VAN), ciprofloxacin (CPR), trimethoprim (TMP), gentamicin (GEN), tetracycline (TET), erythromycin (ERY), and chloramphenicol (CHL) as antibiotics. We detected the strongest synergies with 4NQO, an agent that oxidizes guanines and ultimately results in double-strand breaks when paired with the bactericidal antibiotics VAN, TMP, CPR, and GEN, but no synergies with the bacteriostatic antibiotics TET, ERY, and CHL. Each of the other mutagens displays synergies with the bactericidal antibiotics to various degrees that reflect their potencies, as well as with some of the other mutagens. The results support recent models showing that bactericidal antibiotics kill bacteria principally by ultimately generating more double-strand breaks than can be repaired. We discuss the synergies seen here and elsewhere as representing dose effects of not the proximal target damage but rather the ultimate resulting double-strand breaks. We also used the results of pairwise tests to place the classic mutagens into functional antibacterial categories within a previously defined drug interaction network.

  5. Erasing the traces of classical mechanics in ionization of H{sub 2} by quantum interferences

    SciTech Connect

    Fojon, O. A.; Stia, C. R.; Rivarola, R. D.

    2011-09-15

    The single ionization of hydrogen molecules by fast electron impact is studied theoretically for transitions from the ground (gerade) state to final ground (gerade) and first-excited (ungerade) states of H{sub 2}{sup +}. It is shown that under definite conditions and for particular orientations of the molecule, the main physical features of the ionization reaction, which are the binary and recoil peaks usually associated with classical mechanisms, are completely erased by quantum interference effects that resemble the ones predicted previously for photoionization reactions. However, these new effects cannot be derived from photoionization results, as the electromagnetic field cannot transfer momentum. In addition, it is found that the emission spectra of transitions leading to the final gerade and ungerade states of the H{sub 2}{sup +} residual target are analogous in certain cases to the patterns of two sources emitting waves in phase or antiphase, respectively. Finally, we show how an average of the emission from randomly oriented molecules produces a binary peak at the classical expected position, in agreement with experiments.

  6. Experimental validation of the direct transmissibility approach to classical transfer path analysis on a mechanical setup

    NASA Astrophysics Data System (ADS)

    Guasch, Oriol; García, Carlos; Jové, Jordi; Artís, Pere

    2013-05-01

    Transmissibility functions have received renewed interest given the important role they play in operational modal analysis and operational transfer path analysis. However, transmissibilities can also be used in the framework of classical transmission path analysis. This avoids some of the problems associated to the latter, such as the measurement of operational loads, or the need to remove the active parts of the system to measure frequency response functions. The key of the transmissibility approach to classical transfer path analysis relies on the notion of direct or blocked transmissibilities, which can be computed from standard measurable transmissibilities. The response at any degree of freedom to a system external load can then be decomposed in terms of the remaining degrees of freedom responses and the system direct transmissibilities. Although the theory supporting this approach has been known for long, no experimental validation test has been reported to date. It is the purpose of this paper to provide such a test by applying the method to a simple mechanical system for which an analytical solution can be derived. For different configurations, it will be shown that direct transmissibilities computed from measured transmissibilities compare fairly well with analytical results. This opens the door to apply the method to more complex situations of practical interest with confidence.

  7. Exploring Synergy between Classic Mutagens and Antibiotics To Examine Mechanisms of Synergy and Antibiotic Action

    PubMed Central

    Song, Lisa Yun; D'Souza, Sara; Lam, Karen; Kang, Tina Manzhu

    2015-01-01

    We used classical mutagens in Gram-negative Escherichia coli to study synergies with different classes of antibiotics, test models of antibiotic mechanisms of action, and examine the basis of synergy. We used 4-nitroquinoline 1-oxide (4NQO), zebularine (ZEB), 5-azacytidine (5AZ), 2-aminopurine (2AP), and 5-bromodeoxyuridine (5BrdU) as mutagens (with bactericidal potency of 4NQO > ZEB > 5AZ > 2AP > 5BrdU) and vancomycin (VAN), ciprofloxacin (CPR), trimethoprim (TMP), gentamicin (GEN), tetracycline (TET), erythromycin (ERY), and chloramphenicol (CHL) as antibiotics. We detected the strongest synergies with 4NQO, an agent that oxidizes guanines and ultimately results in double-strand breaks when paired with the bactericidal antibiotics VAN, TMP, CPR, and GEN, but no synergies with the bacteriostatic antibiotics TET, ERY, and CHL. Each of the other mutagens displays synergies with the bactericidal antibiotics to various degrees that reflect their potencies, as well as with some of the other mutagens. The results support recent models showing that bactericidal antibiotics kill bacteria principally by ultimately generating more double-strand breaks than can be repaired. We discuss the synergies seen here and elsewhere as representing dose effects of not the proximal target damage but rather the ultimate resulting double-strand breaks. We also used the results of pairwise tests to place the classic mutagens into functional antibacterial categories within a previously defined drug interaction network. PMID:26711761

  8. On the connection among three classical mechanical problems via the hypercomplex KS-transformation

    NASA Astrophysics Data System (ADS)

    Vivarelli, Maria D.

    In expanding the twofold hypercomplex description of rotational kinematics developed by the author (1984), it is shown that Kustaanheimo-Steifel (KS) theory and rotation theory are linked. Based on the connection, a relationship between three classical mechanical problems is developed which connects one-body pure elliptical Kepler motion, the R3 spherical rotator, and the 4D isotropic harmonic oscillator problems. The KS regularizing transformation is incorporated as the projection map in the Hopf fibering of the contact 3-sphere, and the Euler-Rodrigues parameters are used in a Lagrangian description of the rotational kinematics. A unit vector 'a' is also introduced to characterize both the attitude frame of the rotator and the direction of the major axis of the Kepler orbit. The quantistic mathematical connection of Ikeda and Miyachi (1970) is examined to demonstrate that the resulting Euler angles do not have to be rewritten.

  9. Some reflections on the role of semi-classical atomic models in the teaching and learning of introductory quantum mechanics

    NASA Astrophysics Data System (ADS)

    O'Sullivan, Colm

    2016-03-01

    The role of "semi-classical" (Bohr-Sommerfeld) and "semi-quantum-mechanical" (atomic orbital) models in the context of the teaching of atomic theory is considered. It is suggested that an appropriate treatment of such models can serve as a useful adjunct to quantum mechanical study of atomic systems.

  10. Rings and rackets from single-wall carbon nanotubes: manifestations of mesoscopic mechanics

    NASA Astrophysics Data System (ADS)

    Wang, Yuezhou; Semler, Matthew; Ostanin, Igor; Hobbie, Erik; Dumitrica, Traian

    2015-03-01

    We combine distinct element method simulations and experiments to understand the stability of rings and rackets formed by single-walled carbon nanotubes assembled into ropes. Bending remains a soft deformation mode in ropes because intra-rope sliding of the constituent nanotubes occurs with ease. Our simulations indicate that the formation of these aggregates can be attributed to the mesoscopic mechanics of entangled nanotubes and to the sliding at the contacts. Starting from the single-walled carbon nanotubes, the sizes of the rings and rackets' heads increase with the rope diameter, indicating that the stability of the experimental aggregates can be largely explained by the competition between bending and van der Waals adhesion energies. Our results and simulation method should be useful for understanding nanoscale fibers and self-assembling process in general.

  11. Rings and rackets from single-wall carbon nanotubes: manifestations of mesoscale mechanics.

    PubMed

    Wang, Yuezhou; Semler, Matthew R; Ostanin, Igor; Hobbie, Erik K; Dumitrică, Traian

    2014-11-21

    We combine experiments and distinct element method simulations to understand the stability of rings and rackets formed by single-walled carbon nanotubes assembled into ropes. Bending remains a soft deformation mode in ropes because intra-rope sliding of the constituent nanotubes occurs with ease. Our simulations indicate that the formation of these aggregates can be attributed to the mesoscopic mechanics of entangled nanotubes and to the sliding at the contacts. Starting from the single-walled carbon nanotubes, the sizes of the rings and rackets' heads increase with the rope diameter, indicating that the stability of the experimental aggregates can be largely explained by the competition between bending and van der Waals adhesion energies. Our results and simulation method should be useful for understanding nanoscale fibers in general.

  12. Ab Initio Modeling Of Friction Reducing Agents Shows Quantum Mechanical Interactions Can Have Macroscopic Manifestation.

    PubMed

    Hernández Velázquez, J D; Barroso-Flores, J; Gama Goicochea, A

    2016-11-23

    Two of the most commonly encountered friction-reducing agents used in plastic sheet production are the amides known as erucamide and behenamide, which despite being almost identical chemically, lead to markedly different values of the friction coefficient. To understand the origin of this contrasting behavior, in this work we model brushes made of these two types of linear-chain molecules using quantum mechanical numerical simulations under the density functional theory at the B97D/6-31G(d,p) level of theory. Four chains of erucamide and behenamide were linked to a 2 × 10 zigzag graphene sheet and optimized both in vacuum and in continuous solvent using the SMD implicit solvation model. We find that erucamide chains tend to remain closer together through π-π stacking interactions arising from the double bonds located at C13-C14, a feature behenamide lacks, and thus a more spread configuration is obtained with the latter. It is argued that this arrangement of the erucamide chains is responsible for the lower friction coefficient of erucamide brushes, compared with behenamide brushes, which is a macroscopic consequence of cooperative quantum mechanical interactions. While only quantum level interactions are modeled here, we show that behenamide chains are more spread out in the brush than erucamide chains as a consequence of those interactions. The spread-out configuration allows more solvent particles to penetrate the brush, leading in turn to more friction, in agreement with macroscopic measurements and mesoscale simulations of the friction coefficient reported in the literature.

  13. A proposed mechanism for autism: an aberrant neuroimmune response manifested as a psychiatric disorder.

    PubMed

    Buehler, M R

    2011-06-01

    Autism, an incurable neurodevelopmental brain disorder, is a complex psychopathology in which the affected individual cannot effectively self-regulate their sensory inputs toward coherent and focused motor outputs. There have been many hypotheses as to the etiology of autism - genetics, neurotransmitter imbalances, early childhood immunizations, xenobiotic and teratogenic agents, and maternal infection; the disorder can perhaps be studied best under the field of "Psychoneuroimmunology", which analyzes systemic and psychopathologies from an integrated approach through the combined effects of the nervous, immune, and endocrine systems. Using principles of psychoneuroimmunology along with previously established but yet un-linked scientific principles and observations, this paper proposes a neuroimmune-based mechanistic hypothesis for the etiology of autism that connects elevated levels of maternal pro-inflammatory cytokines to autistic symptoms in her offspring through a logical sequence of events. While both researchers and clinicians often note correlations between pro-inflammatory cytokine levels and autistic symptoms in affected individuals, no specific mechanism has been documented that logically and directly connects the two. I propose that pro-inflammatory cytokines arising from maternal inflammation, infection, and, possibly, autoimmunity, pass through the placenta; enter the fetal circulation; cross the fetal blood-brain barrier (BBB); and cause aberrant neuronal growth and plasticity within the fetal brain via a "cytokine-storm". Microglia and astrocyte stimulation lead to a positive-feedback loop that also facilitates the development of a chronic inflammatory environment within the fetus, pre-disposing it to lifelong comorbid psychiatric and systemic pathologies. Such a mechanism could account for many of the observed symptoms and behaviors of autistic individuals such as hyper-sensitivity to environmental stimuli, object fixation, echolalia, repetitive

  14. Models of dark matter halos based on statistical mechanics: The classical King model

    NASA Astrophysics Data System (ADS)

    Chavanis, Pierre-Henri; Lemou, Mohammed; Méhats, Florian

    2015-03-01

    We consider the possibility that dark matter halos are described by the Fermi-Dirac distribution at finite temperature. This is the case if dark matter is a self-gravitating quantum gas made of massive neutrinos at statistical equilibrium. This is also the case if dark matter can be treated as a self-gravitating collisionless gas experiencing Lynden-Bell's type of violent relaxation. In order to avoid the infinite mass problem and carry out a rigorous stability analysis, we consider the fermionic King model. In this paper, we study the nondegenerate limit leading to the classical King model. This model was initially introduced to describe globular clusters. We propose to apply it also to large dark matter halos where quantum effects are negligible. We determine the caloric curve and study the thermodynamical stability of the different configurations. Equilibrium states exist only above a critical energy Ec in the microcanonical ensemble and only above a critical temperature Tc in the canonical ensemble. For E classical King model to the observations of large dark matter halos. Because of collisions and evaporation, the central density increases while the slope of the halo density profile decreases until an instability takes place. We show that large dark matter halos are relatively well described by the King model at, or close to, the point of marginal microcanonical stability. At that point, the King model generates a density profile that can be approximated by the modified Hubble profile. This profile has a flat core and decreases as r-3 at large distances, like the observational Burkert profile. Less steep halos are unstable. For large halos, the flat core is due to finite temperature effects, not to quantum mechanics. We argue that statistical

  15. Monuments of memory: defensive mechanisms of the collective psyche and their manifestation in the memorialization process.

    PubMed

    Kalinowska, Malgorzata

    2012-09-01

    The paper searches for insight in the area of collective memory as a part of collective consciousness, a phenomenon understood as a stabilizing factor for a society's self-image and identity. Collective memories are seen as originating from shared communications transmitting and creating the meaning of the past in the form of narrative, symbols and signs. As such, they contain the individual, embodied and lived side of our relations to the past. As well as the identity-building and meaning-making functions of collective memories, their defensive function is discussed with a focus on commemorative practices taking place in a transitional space between psychic and social life. Fears of a lack of collective identity and coherence have contributed to the way Polish commemorative practices have been shaped. This is considered in relation to the Smolensk catastrophe in 2010, viewed in the context of the Jungian concept of the collective psyche and the psychoanalytical understanding of defensive group mechanisms against trauma, especially those relating to loss and mourning. It leads to a consideration of how historical experiences and the experience of history can be accessed, as well as their meaning for individual and group development.

  16. Jupiter System Data Analysis Program: Mechanisms, Manifestation, and Implications of Cryomagmatism on Europa

    NASA Technical Reports Server (NTRS)

    Fagents, Sarah A.

    2003-01-01

    The objectives of the work completed under NASA Grant NAG5-8898 were (i) to document and characterize the low-albedo diffuse surfaces associated with triple bands and lenticulae, (ii) to determine their mechanisms of formation, and (iii) to assess the implications of these features for the resurfacing (in space and time) of the Europa and the nature of the Europan interior. The approach involved a combination of processing and analysis of Solid State Imaging data returned by the Galileo spacecraft during the primary and extended mission phases, together with numerical modeling of the physical processes interpreted to the observed features. We have modeled the formation of Europan triple explosive venting of cryoclastic material from bands and lenticulae halos by two processes: (i) a liquid layer in the Europan interior, and (ii) lag deposit formation by the thermal influence of subsurface cryomagmatic intrusions. We favor the latter hypothesis for explaining these features, and further suggest that a liquid water or brine intrusion is required to provide sufficient lateral heating of surface ice to explain the 25 km size of the largest features. (Solid ice diapirs, even under the most favorable conditions, become thermally exhausted before they heat significant lateral distances). We argue that water circulating in open fractures, or repeated cryomagmatic 'diking' events would provide sufficient thermal input to produce the observed features. Thus our work argues for the existence of a liquid beneath Europa's surface. Our results might most easily be explained by the presence of a continuous liquid layer (the putative Europan ocean); this would concur with the findings of the Galileo magnetometer team. However, we cannot rule out the possibility that discrete liquid pockets provide injections of fluid closer to the surface.

  17. Quantum-mechanical machinery for rational decision-making in classical guessing game

    NASA Astrophysics Data System (ADS)

    Bang, Jeongho; Ryu, Junghee; Pawłowski, Marcin; Ham, Byoung S.; Lee, Jinhyoung

    2016-02-01

    In quantum game theory, one of the most intriguing and important questions is, “Is it possible to get quantum advantages without any modification of the classical game?” The answer to this question so far has largely been negative. So far, it has usually been thought that a change of the classical game setting appears to be unavoidable for getting the quantum advantages. However, we give an affirmative answer here, focusing on the decision-making process (we call ‘reasoning’) to generate the best strategy, which may occur internally, e.g., in the player’s brain. To show this, we consider a classical guessing game. We then define a one-player reasoning problem in the context of the decision-making theory, where the machinery processes are designed to simulate classical and quantum reasoning. In such settings, we present a scenario where a rational player is able to make better use of his/her weak preferences due to quantum reasoning, without any altering or resetting of the classically defined game. We also argue in further analysis that the quantum reasoning may make the player fail, and even make the situation worse, due to any inappropriate preferences.

  18. Quantum-mechanical machinery for rational decision-making in classical guessing game.

    PubMed

    Bang, Jeongho; Ryu, Junghee; Pawłowski, Marcin; Ham, Byoung S; Lee, Jinhyoung

    2016-02-15

    In quantum game theory, one of the most intriguing and important questions is, "Is it possible to get quantum advantages without any modification of the classical game?" The answer to this question so far has largely been negative. So far, it has usually been thought that a change of the classical game setting appears to be unavoidable for getting the quantum advantages. However, we give an affirmative answer here, focusing on the decision-making process (we call 'reasoning') to generate the best strategy, which may occur internally, e.g., in the player's brain. To show this, we consider a classical guessing game. We then define a one-player reasoning problem in the context of the decision-making theory, where the machinery processes are designed to simulate classical and quantum reasoning. In such settings, we present a scenario where a rational player is able to make better use of his/her weak preferences due to quantum reasoning, without any altering or resetting of the classically defined game. We also argue in further analysis that the quantum reasoning may make the player fail, and even make the situation worse, due to any inappropriate preferences.

  19. Quantum-mechanical machinery for rational decision-making in classical guessing game

    PubMed Central

    Bang, Jeongho; Ryu, Junghee; Pawłowski, Marcin; Ham, Byoung S.; Lee, Jinhyoung

    2016-01-01

    In quantum game theory, one of the most intriguing and important questions is, “Is it possible to get quantum advantages without any modification of the classical game?” The answer to this question so far has largely been negative. So far, it has usually been thought that a change of the classical game setting appears to be unavoidable for getting the quantum advantages. However, we give an affirmative answer here, focusing on the decision-making process (we call ‘reasoning’) to generate the best strategy, which may occur internally, e.g., in the player’s brain. To show this, we consider a classical guessing game. We then define a one-player reasoning problem in the context of the decision-making theory, where the machinery processes are designed to simulate classical and quantum reasoning. In such settings, we present a scenario where a rational player is able to make better use of his/her weak preferences due to quantum reasoning, without any altering or resetting of the classically defined game. We also argue in further analysis that the quantum reasoning may make the player fail, and even make the situation worse, due to any inappropriate preferences. PMID:26875685

  20. Therapeutic mechanisms of classic hallucinogens in the treatment of addictions: from indirect evidence to testable hypotheses.

    PubMed

    Bogenschutz, Michael P; Pommy, Jessica M

    2012-01-01

    Alcohol and drug addiction are major public health problems, and existing treatments are only moderately effective. Although there has been interest for over half a century in the therapeutic use of classic hallucinogens to treat addictions, clinical research with these drugs was halted at an early stage in the early 1970s, leaving many fundamental questions unanswered. In the past two decades, clinical research on classic hallucinogens has resumed, although addiction treatment trials are only now beginning. The purpose of this paper is to provide a targeted review of the research most relevant to the therapeutic potential of hallucinogens, and to integrate this information with current thinking about addiction and recovery. On the basis of this information, we present a heuristic model which organizes a number of hypotheses that may be tested in future research. We conclude that existing evidence provides a convincing rationale for further research on the effects of classic hallucinogens in the treatment of addiction.

  1. Thermodynamics and equilibrium structure of Ne38 cluster: quantum mechanics versus classical.

    PubMed

    Predescu, Cristian; Frantsuzov, Pavel A; Mandelshtam, Vladimir A

    2005-04-15

    The equilibrium properties of classical Lennard-Jones (LJ38) versus quantum Ne38 Lennard-Jones clusters are investigated. The quantum simulations use both the path-integral Monte Carlo (PIMC) and the recently developed variational-Gaussian wave packet Monte Carlo (VGW-MC) methods. The PIMC and the classical MC simulations are implemented in the parallel tempering framework. The classical heat capacity Cv(T) curve agrees well with that of Neirotti et al. [J. Chem. Phys. 112, 10340 (2000)], although a much larger confining sphere is used in the present work. The classical Cv(T) shows a peak at about 6 K, interpreted as a solid-liquid transition, and a shoulder at approximately 4 K, attributed to a solid-solid transition involving structures from the global octahedral (Oh) minimum and the main icosahedral (C5v) minimum. The VGW method is used to locate and characterize the low energy states of Ne38, which are then further refined by PIMC calculations. Unlike the classical case, the ground state of Ne38 is a liquidlike structure. Among the several liquidlike states with energies below the two symmetric states (Oh and C5v), the lowest two exhibit strong delocalization over basins associated with at least two classical local minima. Because the symmetric structures do not play an essential role in the thermodynamics of Ne38, the quantum heat capacity is a featureless curve indicative of the absence of any structural transformations. Good agreement between the two methods, VGW and PIMC, is obtained. The present results are also consistent with the predictions by Calvo et al. [J. Chem. Phys. 114, 7312 (2001)] based on the quantum superposition method within the harmonic approximation. However, because of its approximate nature, the latter method leads to an incorrect assignment of the Ne38 ground state as well as to a significant underestimation of the heat capacity.

  2. Rotational excitation of water by hydrogen molecules: comparison of results from classical and quantum mechanics.

    PubMed

    Faure, Alexandre; Wiesenfeld, Laurent; Wernli, Michael; Valiron, Pierre

    2006-06-07

    Quasiclassical trajectory calculations are carried out for rotational excitation of water by hydrogen molecules. State-to-state rate coefficients are determined at 100 K and are compared to available quantum results. A good agreement between classical and quantum rates is observed for downward transitions, with an average accuracy of classical results better than a factor of 2. It is thus found that the ambiguities described by Faure and Wiesenfeld [J. Chem. Phys. 121, 6771 (2004)] can be solved in the particular case of waterlike asymmetric-top molecules.

  3. The dynamics of the H(+) + D(2) reaction: a comparison of quantum mechanical wavepacket, quasi-classical and statistical-quasi-classical results.

    PubMed

    Jambrina, P G; Aoiz, F J; Bulut, N; Smith, Sean C; Balint-Kurti, G G; Hankel, M

    2010-02-07

    A detailed study of the proton exchange reaction H(+) + D(2)(v = 0, j = 0) --> HD + D(+) on its ground 1(1)A' potential energy surface has been carried out using 'exact' close-coupled quantum mechanical wavepacket (WP-EQM), quasi-classical trajectory (QCT), and statistical quasi-classical trajectory (SQCT) calculations for a range of collision energies starting from the reaction threshold to 1.3 eV. The WP-EQM calculations include all total angular momenta up to J(max) = 50, and therefore the various dynamical observables are converged up to 0.6 eV. It has been found that it is necessary to include all Coriolis couplings to obtain reliable converged results. Reaction probabilities obtained using the different methods are thoroughly compared as a function of the total energy for a series of J values. Comparisons are also made of total reaction cross sections as function of the collision energy, and rate constants. In addition, opacity functions, integral cross sections (ICS) and differential cross sections (DCS) are presented at 102 meV, 201.3 meV and 524.6 meV collision energy. The agreement between the three sets of results is only qualitative. The QCT calculations fail to describe the overall reactivity and most of the dynamical observables correctly. At low collision energies, the QCT method is plagued by the lack of conservation of zero point energy, whilst at higher collision energies and/or total angular momenta, the appearance of an effective repulsive potential associated with the centrifugal motion "over" the well causes a substantial decrease of the reactivity. In turn, the statistical models overestimate the reactivity over the whole range of collision energies as compared with the WP-EQM method. Specifically, at sufficiently high collision energies the reaction cannot be deemed to be statistical and important dynamical effects seem to be present. In general the WP-EQM results lie in between those obtained using the QCT and SQCT methods. One of the main

  4. Non-Noetherian symmetries for oscillators in classical mechanics and in field theory

    NASA Technical Reports Server (NTRS)

    Hojman, Sergio A.; Delajara, Jamie; Pena, Leda

    1995-01-01

    Infinitely many new conservation laws both for free fields as well as for test fields evolving on a given gravitational background are presented. The conserved currents are constructed using the field theoretical counterpart of a recently discovered non-Noetherian symmetry which gives rise to a new way of solving the classical small oscillations problem. Several examples are discussed.

  5. Generalization of the Activated Complex Theory of Reaction Rates. II. Classical Mechanical Treatment

    DOE R&D Accomplishments Database

    Marcus, R. A.

    1964-01-01

    In its usual classical form activated complex theory assumes a particular expression for the kinetic energy of the reacting system -- one associated with a rectilinear motion along the reaction coordinate. The derivation of the rate expression given in the present paper is based on the general kinetic energy expression.

  6. Mechanism of the Glycosidic Bond Cleavage of Mismatched Thymine in Human Thymine DNA Glycosylase Revealed by Classical Molecular Dynamics and Quantum Mechanical/Molecular Mechanical Calculations.

    PubMed

    Kanaan, Natalia; Crehuet, Ramon; Imhof, Petra

    2015-09-24

    Base excision of mismatched or damaged nucleotides catalyzed by glycosylase enzymes is the first step of the base excision repair system, a machinery preserving the integrity of DNA. Thymine DNA glycosylase recognizes and removes mismatched thymine by cleaving the C1'-N1 bond between the base and the sugar ring. Our quantum mechanical/molecular mechanical calculations of this reaction in human thymine DNA glycosylase reveal a requirement for a positive charge in the active site to facilitate C1'-N1 bond scission: protonation of His151 significantly lowers the free energy barrier for C1'-N1 bond dissociation compared to the situation with neutral His151. Shuttling a proton from His151 to the thymine base further reduces the activation free energy for glycosidic bond cleavage. Classical molecular dynamics simulations of the H151A mutant suggest that the mutation to the smaller, neutral, residue increases the water accessibility of the thymine base, rendering direct proton transfer from the bulk feasible. Quantum mechanical/molecular mechanical calculations of the glycosidic bond cleavage reaction in the H151A mutant show that the activation free energy is slightly lower than in the wild-type enzyme, explaining the experimentally observed higher reaction rates in this mutant.

  7. Mechanistic insights into Mg2+-independent prenylation by CloQ from classical molecular mechanics and hybrid quantum mechanics/molecular mechanics molecular dynamics simulations.

    PubMed

    Bayse, Craig A; Merz, Kenneth M

    2014-08-05

    Understanding the mechanism of prenyltransferases is important to the design of engineered proteins capable of synthesizing derivatives of naturally occurring therapeutic agents. CloQ is a Mg(2+)-independent aromatic prenyltransferase (APTase) that transfers a dimethylallyl group to 4-hydroxyphenylpyruvate in the biosynthetic pathway for clorobiocin. APTases consist of a common ABBA fold that defines a β-barrel containing the reaction cavity. Positively charged basic residues line the inside of the β-barrel of CloQ to activate the pyrophosphate leaving group to replace the function of the Mg(2+) cofactor in other APTases. Classical molecular dynamics simulations of CloQ, its E281G and F68S mutants, and the related NovQ were used to explore the binding of the 4-hydroxyphenylpyruvate (4HPP) and dimethylallyl diphosphate substrates in the reactive cavity and the role of various conserved residues. Hybrid quantum mechanics/molecular mechanics potential of mean force (PMF) calculations show that the effect of the replacement of the Mg(2+) cofactor with basic residues yields a similar activation barrier for prenylation to Mg(2+)-dependent APTases like NphB. The topology of the binding pocket for 4HPP is important for selective prenylation at the ortho position of the ring. Methylation at this position alters the conformation of the substrate for O-prenylation at the phenol group. Further, a two-dimensional PMF scan shows that a "reverse" prenylation product may be a possible target for protein engineering.

  8. Heat control in opto-mechanical system using quantum non-classicality

    NASA Astrophysics Data System (ADS)

    Sharma, Sushamana; Senwar, Subash

    2016-05-01

    Cooling of matter to the quantum ground state is a primary directive of quantum control. In other words, to extract entropy from a quantum system, efficient indirect quantum measurements may be implemented. The main objective is the cooling of the oscillator either to its motional ground state or to non-classical states, such as low-number Fock states, squeezed states or entangled states. It is shown that the use of quantum control procedure is better choice for even experimental realizations because it leads to a squeezed steady state with less than one phonon on average. The steady state of system corresponds to cooling of the system.

  9. The classical and quantum mechanics of a particle on a knot

    SciTech Connect

    Sreedhar, V.V.

    2015-08-15

    A free particle is constrained to move on a knot obtained by winding around a putative torus. The classical equations of motion for this system are solved in a closed form. The exact energy eigenspectrum, in the thin torus limit, is obtained by mapping the time-independent Schrödinger equation to the Mathieu equation. In the general case, the eigenvalue problem is described by the Hill equation. Finite-thickness corrections are incorporated perturbatively by truncating the Hill equation. Comparisons and contrasts between this problem and the well-studied problem of a particle on a circle (planar rigid rotor) are performed throughout.

  10. Structural transformations and melting in neon clusters: quantum versus classical mechanics.

    PubMed

    Frantsuzov, Pavel A; Meluzzi, Dario; Mandelshtam, Vladimir A

    2006-03-24

    The extraordinary complexity of Lennard-Jones (LJ) clusters, which exhibit numerous structures and "phases" when their size or temperature is varied, presents a great challenge for accurate numerical simulations, even without accounting for quantum effects. To study the latter, we utilize the variational Gaussian wave packet method in conjunction with the exchange Monte Carlo sampling technique. We show that the quantum nature of neon clusters has a substantial effect on their size-temperature "phase diagrams," particularly the critical parameters of certain structural transformations. We also give a numerical confirmation that none of the nonicosahedral structures observed for some classical LJ clusters are favorable in the quantum case.

  11. Nonequilibrium statistical mechanics of mixed quantum classical ensembles: application to noncontact atomic force microscopy.

    PubMed

    Kantorovich, L N

    2002-08-26

    Using the nonequilibrium statistical operator method, we suggest a new general method of treating dynamics of a combined system consisting of interacting classical and quantum parts. The method is illustrated on the tip dynamics in the noncontact atomic force microscopy (NC-AFM) where a macroscopic tip interacts with a quantum microscopic system (the surface and the nanotip). The derived general equation of motion for the tip and the Fokker-Planck equation, applicable even at low temperatures, contain memory effects and a friction term which should (at least partially) be responsible for the observed energy dissipation in NC-AFM experiments.

  12. Dynamics of classical particles in oval or elliptic billiards with a dispersing mechanism

    SciTech Connect

    Costa, Diogo Ricardo da; Dettmann, Carl P.; Oliveira, Juliano A. de; Leonel, Edson D.

    2015-03-15

    Some dynamical properties for an oval billiard with a scatterer in its interior are studied. The dynamics consists of a classical particle colliding between an inner circle and an external boundary given by an oval, elliptical, or circle shapes, exploring for the first time some natural generalizations. The billiard is indeed a generalization of the annular billiard, which is of strong interest for understanding marginally unstable periodic orbits and their role in the boundary between regular and chaotic regions in both classical and quantum (including experimental) systems. For the oval billiard, which has a mixed phase space, the presence of an obstacle is an interesting addition. We demonstrate, with details, how to obtain the equations of the mapping, and the changes in the phase space are discussed. We study the linear stability of some fixed points and show both analytically and numerically the occurrence of direct and inverse parabolic bifurcations. Lyapunov exponents and generalized bifurcation diagrams are obtained. Moreover, histograms of the number of successive iterations for orbits that stay in a cusp are studied. These histograms are shown to be scaling invariant when changing the radius of the scatterer, and they have a power law slope around −3. The results here can be generalized to other kinds of external boundaries.

  13. A study of quantum mechanical probabilities in the classical Hodgkin-Huxley model.

    PubMed

    Moradi, N; Scholkmann, F; Salari, V

    2015-03-01

    The Hodgkin-Huxley (HH) model is a powerful model to explain different aspects of spike generation in excitable cells. However, the HH model was proposed in 1952 when the real structure of the ion channel was unknown. It is now common knowledge that in many ion-channel proteins the flow of ions through the pore is governed by a gate, comprising a so-called "selectivity filter" inside the ion channel, which can be controlled by electrical interactions. The selectivity filter (SF) is believed to be responsible for the selection and fast conduction of particular ions across the membrane of an excitable cell. Other (generally larger) parts of the molecule such as the pore-domain gate control the access of ions to the channel protein. In fact, two types of gates are considered here for ion channels: the "external gate", which is the voltage sensitive gate, and the "internal gate" which is the selectivity filter gate (SFG). Some quantum effects are expected in the SFG due to its small dimensions, which may play an important role in the operation of an ion channel. Here, we examine parameters in a generalized model of HH to see whether any parameter affects the spike generation. Our results indicate that the previously suggested semi-quantum-classical equation proposed by Bernroider and Summhammer (BS) agrees strongly with the HH equation under different conditions and may even provide a better explanation in some cases. We conclude that the BS model can refine the classical HH model substantially.

  14. Systemic gene dysregulation in classical Galactosaemia: Is there a central mechanism?

    PubMed

    Coss, K P; Treacy, E P; Cotter, E J; Knerr, I; Murray, D W; Shin, Y S; Doran, P P

    2014-11-01

    Classical Galactosaemia is a rare disorder of carbohydrate metabolism caused by a deficiency of galactose-1-phosphate uridyltransferase (GALT). The disease is life-threatening in the neonate, and the only treatment option is life-long dietary restriction of galactose. However, long-term complications persist in treated patients including cognitive impairments, speech and language abnormalities and premature ovarian insufficiency in females. Microarray analysis of T-lymphocytes from treated adult patients identified systemic dysregulation of numerous gene pathways, including the glycosylation, inflammatory and inositol pathways. Analysis of gene expression in patient-derived dermal fibroblasts of patients exposed to toxic levels of galactose, with immunostaining, has further identified the susceptibility of the glycosylation gene alpha-1,2-mannosyltransferase (ALG9) and the inflammatory gene annexin A1 (ANXA1) to increased galactose concentrations. These data suggest that Galactosaemia is a multi-system disorder affecting numerous signalling pathways.

  15. Mechanisms involved in vitamin D mediated intestinal calcium absorption and in non-classical actions of vitamin D.

    PubMed

    Christakos, Sylvia; Dhawan, Puneet; Ajibade, Dare; Benn, Bryan S; Feng, Jingjing; Joshi, Sneha S

    2010-07-01

    Recent studies in our laboratory using calbindin-D9k null mutant mice as well as mice lacking the 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) inducible epithelial calcium channel TRPV6 provide evidence for calbindin-D9k and TRPV6 independent regulation of active intestinal calcium absorption. These findings suggest that in the knock out (KO) mice there is compensation by another calcium channel or protein and that other novel factors are involved in 1,25(OH)2D3 mediated active intestinal calcium absorption. In addition, 1,25(OH)2D3 mediated paracellular transport of calcium may have contributed to the normalization of serum calcium in the null mutant mice. 1,25(OH)2D3 downregulates cadherin-17 and upregulates claudin-2 and claudin-12 in the intestine, suggesting that 1,25(OH)2D3, by regulating these epithelial cell junction proteins, can route calcium through the paracellular path. With regard to non-classical actions, 1,25(OH)2D3 has been reported to inhibit the proliferation of a number of malignant cells and to regulate adaptive as well as innate immunity. This article will review new developments related to the function and regulation of vitamin D target proteins in classical and non-classical vitamin D target tissues that have provided novel insight into mechanisms of vitamin D action.

  16. Comparison Of Quantum Mechanical And Classical Trajectory Calculations Of Cross Sections For Ion-Atom Impact Ionization of Negative - And Positive -Ions For Heavy Ion Fusion Applications

    SciTech Connect

    Igor D. Kaganovich; Edward A. Startsev; Ronald C. Davidson

    2003-05-15

    Stripping cross sections in nitrogen have been calculated using the classical trajectory approximation and the Born approximation of quantum mechanics for the outer shell electrons of 3.2GeV I{sup -} and Cs{sup +} ions. A large difference in cross section, up to a factor of six, calculated in quantum mechanics and classical mechanics, has been obtained. Because at such high velocities the Born approximation is well validated, the classical trajectory approach fails to correctly predict the stripping cross sections at high energies for electron orbitals with low ionization potential.

  17. Historical and critical review of the development of nonholonomic mechanics: the classical period

    NASA Astrophysics Data System (ADS)

    Borisov, Alexey V.; Mamaev, Ivan S.; Bizyaev, Ivan A.

    2016-07-01

    In this historical review we describe in detail the main stages of the development of nonholonomic mechanics starting from the work of Earnshaw and Ferrers to the monograph of Yu. I.Neimark and N.A. Fufaev. In the appendix to this review we discuss the d'Alembert-Lagrange principle in nonholonomic mechanics and permutation relations.

  18. Probing wave function collapse models with a classically driven mechanical oscillator

    NASA Astrophysics Data System (ADS)

    Ho, Melvyn; Lafont, Ambroise; Sangouard, Nicolas; Sekatski, Pavel

    2016-03-01

    We show that the interaction of a pulsed laser light with a mechanical oscillator through the radiation pressure results in an opto-mechanical entangled state in which the photon number is correlated with the oscillator position. Interestingly, the mechanical oscillator can be delocalized over a large range of positions when driven by an intense laser light. This provides a simple yet sensitive method to probe hypothetical post-quantum theories including an explicit wave function collapse model, like the Diosi & Penrose model. We propose an entanglement witness to reveal the quantum nature of this opto-mechanical state as well as an optical technique to record the decoherence of the mechanical oscillator. We also report on a detailed feasibility study giving the experimental challenges that need to be overcome in order to confirm or rule out predictions from explicit wave function collapse models.

  19. The safety of electronic prescribing: manifestations, mechanisms, and rates of system-related errors associated with two commercial systems in hospitals

    PubMed Central

    Westbrook, Johanna I; Baysari, Melissa T; Li, Ling; Burke, Rosemary; Richardson, Katrina L; Day, Richard O

    2013-01-01

    Objectives To compare the manifestations, mechanisms, and rates of system-related errors associated with two electronic prescribing systems (e-PS). To determine if the rate of system-related prescribing errors is greater than the rate of errors prevented. Methods Audit of 629 inpatient admissions at two hospitals in Sydney, Australia using the CSC MedChart and Cerner Millennium e-PS. System related errors were classified by manifestation (eg, wrong dose), mechanism, and severity. A mechanism typology comprised errors made: selecting items from drop-down menus; constructing orders; editing orders; or failing to complete new e-PS tasks. Proportions and rates of errors by manifestation, mechanism, and e-PS were calculated. Results 42.4% (n=493) of 1164 prescribing errors were system-related (78/100 admissions). This result did not differ by e-PS (MedChart 42.6% (95% CI 39.1 to 46.1); Cerner 41.9% (37.1 to 46.8)). For 13.4% (n=66) of system-related errors there was evidence that the error was detected prior to study audit. 27.4% (n=135) of system-related errors manifested as timing errors and 22.5% (n=111) wrong drug strength errors. Selection errors accounted for 43.4% (34.2/100 admissions), editing errors 21.1% (16.5/100 admissions), and failure to complete new e-PS tasks 32.0% (32.0/100 admissions). MedChart generated more selection errors (OR=4.17; p=0.00002) but fewer new task failures (OR=0.37; p=0.003) relative to the Cerner e-PS. The two systems prevented significantly more errors than they generated (220/100 admissions (95% CI 180 to 261) vs 78 (95% CI 66 to 91)). Conclusions System-related errors are frequent, yet few are detected. e-PS require new tasks of prescribers, creating additional cognitive load and error opportunities. Dual classification, by manifestation and mechanism, allowed identification of design features which increase risk and potential solutions. e-PS designs with fewer drop-down menu selections may reduce error risk. PMID:23721982

  20. [Mechanisms and regulation of enzymatic hydrolysis of cellulose in filamentous fungi: classical cases and new models].

    PubMed

    Gutiérrez-Rojas, Ivonne; Moreno-Sarmiento, Nubia; Montoya, Dolly

    2015-01-01

    Cellulose is the most abundant renewable carbon source on earth. However, this polymer structure comprises a physical and chemical barrier for carbon access, which has limited its exploitation. In nature, only a few percentage of microorganisms may degrade this polymer by cellulase expression. Filamentous fungi are one of the most active and efficient groups among these microorganisms. This review describes similarities and differences between cellulase activity mechanisms and regulatory mechanisms controlling gene expression for 3 of the most studied cellulolytic filamentous fungi models: Trichoderma reesei, Aspergillus niger and Aspergillus nidulans, and the recently described model Neurospora crassa. Unlike gene expression mechanisms, it was found that enzymatic activity mechanisms are similar for all the studied models. Understanding the distinctive elements of each system is essential for the development of strategies for the improvement of cellulase production, either by providing the optimum environment (fermentation conditions) or increasing gene expression in these microorganisms by genetic engineering.

  1. Energy Transfer Sensitization of Luminescent Gold Nanoclusters: More than Just the Classical Förster Mechanism

    NASA Astrophysics Data System (ADS)

    Oh, Eunkeu; Huston, Alan L.; Shabaev, Andrew; Efros, Alexander; Currie, Marc; Susumu, Kimihiro; Bussmann, Konrad; Goswami, Ramasis; Fatemi, Fredrik K.; Medintz, Igor L.

    2016-10-01

    Luminescent gold nanocrystals (AuNCs) are a recently-developed material with potential optic, electronic and biological applications. They also demonstrate energy transfer (ET) acceptor/sensitization properties which have been ascribed to Förster resonance energy transfer (FRET) and, to a lesser extent, nanosurface energy transfer (NSET). Here, we investigate AuNC acceptor interactions with three structurally/functionally-distinct donor classes including organic dyes, metal chelates and semiconductor quantum dots (QDs). Donor quenching was observed for every donor-acceptor pair although AuNC sensitization was only observed from metal-chelates and QDs. FRET theory dramatically underestimated the observed energy transfer while NSET-based damping models provided better fits but could not reproduce the experimental data. We consider additional factors including AuNC magnetic dipoles, density of excited-states, dephasing time, and enhanced intersystem crossing that can also influence ET. Cumulatively, data suggests that AuNC sensitization is not by classical FRET or NSET and we provide a simplified distance-independent ET model to fit such experimental data.

  2. Energy Transfer Sensitization of Luminescent Gold Nanoclusters: More than Just the Classical Förster Mechanism

    PubMed Central

    Oh, Eunkeu; Huston, Alan L.; Shabaev, Andrew; Efros, Alexander; Currie, Marc; Susumu, Kimihiro; Bussmann, Konrad; Goswami, Ramasis; Fatemi, Fredrik K.; Medintz, Igor L.

    2016-01-01

    Luminescent gold nanocrystals (AuNCs) are a recently-developed material with potential optic, electronic and biological applications. They also demonstrate energy transfer (ET) acceptor/sensitization properties which have been ascribed to Förster resonance energy transfer (FRET) and, to a lesser extent, nanosurface energy transfer (NSET). Here, we investigate AuNC acceptor interactions with three structurally/functionally-distinct donor classes including organic dyes, metal chelates and semiconductor quantum dots (QDs). Donor quenching was observed for every donor-acceptor pair although AuNC sensitization was only observed from metal-chelates and QDs. FRET theory dramatically underestimated the observed energy transfer while NSET-based damping models provided better fits but could not reproduce the experimental data. We consider additional factors including AuNC magnetic dipoles, density of excited-states, dephasing time, and enhanced intersystem crossing that can also influence ET. Cumulatively, data suggests that AuNC sensitization is not by classical FRET or NSET and we provide a simplified distance-independent ET model to fit such experimental data. PMID:27774984

  3. Combining classical and molecular approaches elaborates on the complexity of mechanisms underpinning anterior regeneration.

    PubMed

    Evans, Deborah J; Owlarn, Suthira; Tejada Romero, Belen; Chen, Chen; Aboobaker, A Aziz

    2011-01-01

    The current model of planarian anterior regeneration evokes the establishment of low levels of Wnt signalling at anterior wounds, promoting anterior polarity and subsequent elaboration of anterior fate through the action of the TALE class homeodomain PREP. The classical observation that decapitations positioned anteriorly will regenerate heads more rapidly than posteriorly positioned decapitations was among the first to lead to the proposal of gradients along an anteroposterior (AP) axis in a developmental context. An explicit understanding of this phenomenon is not included in the current model of anterior regeneration. This raises the question what the underlying molecular and cellular basis of this temporal gradient is, whether it can be explained by current models and whether understanding the gradient will shed light on regenerative events. Differences in anterior regeneration rate are established very early after amputation and this gradient is dependent on the activity of Hedgehog (Hh) signalling. Animals induced to produce two tails by either Smed-APC-1(RNAi) or Smed-ptc(RNAi) lose anterior fate but form previously described ectopic anterior brain structures. Later these animals form peri-pharyngeal brain structures, which in Smed-ptc(RNAi) grow out of the body establishing a new A/P axis. Combining double amputation and hydroxyurea treatment with RNAi experiments indicates that early ectopic brain structures are formed by uncommitted stem cells that have progressed through S-phase of the cell cycle at the time of amputation. Our results elaborate on the current simplistic model of both AP axis and brain regeneration. We find evidence of a gradient of hedgehog signalling that promotes posterior fate and temporarily inhibits anterior regeneration. Our data supports a model for anterior brain regeneration with distinct early and later phases of regeneration. Together these insights start to delineate the interplay between discrete existing, new, and then

  4. Dehydration rate and time of desiccation affect recovery of the lichen alga [corrected] Trebouxia erici: alternative and classical protective mechanisms.

    PubMed

    Gasulla, Francisco; de Nova, Pedro Gómez; Esteban-Carrasco, Alberto; Zapata, José M; Barreno, Eva; Guéra, Alfredo

    2009-12-01

    The mechanisms involved in desiccation tolerance of lichens and their photobionts are still poorly understood. To better understand these mechanisms we have studied dehydration rate and desiccation time in Trebouxia, the most abundant chlorophytic photobiont in lichen. Our findings indicate that the drying rate has a profound effect on the recovery of photosynthetic activity of algae after rehydration, greater than the effects of desiccation duration. The basal fluorescence (F'(o)) values in desiccated algae were significantly higher after rapid dehydration, than after slow dehydration, suggesting higher levels of light energy dissipation in slow-dried algae. Higher values of PSII electron transport were recovered after rehydration of slow-dried Trebouxia erici compared to rapid-dried algae. The main component of non-photochemical quenching after slow dehydration was energy dependent (q (E)), whereas after fast dehydration it was photoinhibition (q (I)). Although q (E) seems to play a role during desiccation recovery, no significant variations were detected in the xanthophyll cycle components. Desiccation did not affect PSI functionality. Classical antioxidant activities like superoxide dismutase or peroxidase decreased during desiccation and early recovery. Dehydrins were detected in the lichen-forming algae T. erici and were constitutively expressed. There is probably a minimal period required to develop strategies which will facilitate transition to the desiccated state in this algae. In this process, the xanthophyll cycle and classical antioxidant mechanisms play a very limited role, if any. However, our results indicate that there is an alternative mechanism of light energy dissipation during desiccation, where activation is dependent on a sufficiently slow dehydration rate.

  5. Mucocutaneous manifestations of Cowden's syndrome

    PubMed Central

    Reddy, Kundoor Vinay Kumar; Anusha, Amarthuluri; Maloth, Kotya Naik; Sunitha, Kesidi; Thakur, Moni

    2016-01-01

    Cowden's syndrome is an autosomal dominant genodermatosis with variable orofacial and systemic manifestations. Here we present one such classical case of Cowden's syndrome in a 45-year-old female patient with features such as multiple cutaneous papillomatosis, oral fibromas, and fibromas involving multiple organs such as gastrointestinal tract (multiple polyps), thyroid disorders, and breast cancer. PMID:27990388

  6. Mechanics of neurulation: From classical to current perspectives on the physical mechanics that shape, fold, and form the neural tube.

    PubMed

    Vijayraghavan, Deepthi S; Davidson, Lance A

    2016-09-13

    Neural tube defects arise from mechanical failures in the process of neurulation. At the most fundamental level, formation of the neural tube relies on coordinated, complex tissue movements that mechanically transform the flat neural epithelium into a lumenized epithelial tube (Davidson, 2012). The nature of this mechanical transformation has mystified embryologists, geneticists, and clinicians for more than 100 years. Early embryologists pondered the physical mechanisms that guide this transformation. Detailed observations of cell and tissue movements as well as experimental embryological manipulations allowed researchers to generate and test elementary hypotheses of the intrinsic and extrinsic forces acting on the neural tissue. Current research has turned toward understanding the molecular mechanisms underlying neurulation. Genetic and molecular perturbation have identified a multitude of subcellular components that correlate with cell behaviors and tissue movements during neural tube formation. In this review, we focus on methods and conceptual frameworks that have been applied to the study of amphibian neurulation that can be used to determine how molecular and physical mechanisms are integrated and responsible for neurulation. We will describe how qualitative descriptions and quantitative measurements of strain, force generation, and tissue material properties as well as simulations can be used to understand how embryos use morphogenetic programs to drive neurulation. Birth Defects Research (Part A), 2016. © 2016 Wiley Periodicals, Inc.

  7. A Formal Derivation of the Gibbs Entropy for Classical Systems Following the Schrodinger Quantum Mechanical Approach

    ERIC Educational Resources Information Center

    Santillan, M.; Zeron, E. S.; Del Rio-Correa, J. L.

    2008-01-01

    In the traditional statistical mechanics textbooks, the entropy concept is first introduced for the microcanonical ensemble and then extended to the canonical and grand-canonical cases. However, in the authors' experience, this procedure makes it difficult for the student to see the bigger picture and, although quite ingenuous, the subtleness of…

  8. Racemization of Isobornyl Chloride via Carbocations: A Nonclassical Look at a Classic Mechanism

    ERIC Educational Resources Information Center

    Rzepa, Henry S.; Allan, Charlotte S. M.

    2010-01-01

    Our understanding of carbonium ions as intermediates in chemical reaction mechanisms derives from the early work of Julius Stieglitz and the more famous Hans Meerwein, the latter studying the racemization of isobornyl chloride when treated with Lewis acids. This review analyzes how key mechanistic concepts for this reaction evolved and gives the…

  9. The road to matrix mechanics: I. Classical interpretation of the anomalous optical dispersion

    NASA Astrophysics Data System (ADS)

    Crivellari, Lucio

    2016-09-01

    This paper is the first one of a series of two on the role of the optical dispersion in the historical development of early quantum mechanics. As preparation for the successive paper on Ladenburg’s development of the phenomenological theory of radiative transitions between the stationary states of an atom by Einstein, we present here the current theories on optical dispersion between the second half of the 19th century and the beginning of the 20th century.

  10. Dynamics of Observed Reality: Abridged Version of Classical and Quantum Mechanics

    DTIC Science & Technology

    1988-08-01

    34 J. A. Wheeler and W. H. Zurek, eds., Princeton University Press, New Jersey (1983). [51 J. M. Gracia-Bondia and J. C. Varilly, EysLtt, A128:20 (1988...R. P. Feynman and A. R. Hibbs, "Quantum Mechanics and Path Integrals," McGraw-Hill, New York (1965). I p -u y DL/ 1113/86/2 TECHNICAL REPORT

  11. Exact statistical mechanical lattice model and classical Lindemann theory of melting of inert gas solids

    NASA Astrophysics Data System (ADS)

    Dunne, Lawrence J.; Murrell, John N.; Manos, George

    2008-05-01

    A modified form of Lindemann's model shows that the melting points of the heavy inert gases and other effectively spherical molecular species are proportional to the depths of their diatomic potential wells. The success of the model when compared with experiment seems to rely on the almost constant value of the ratio of the fractional volume and entropy changes during fusion. The Lindemann proposal can be incorporated into an exactly treated statistical mechanical lattice model utilising expandable clusters which reproduces the solid-liquid melting phenomenon for argon with a realistic volume change and melting line.

  12. Computational algorithms dealing with the classical and statistical mechanics of celestial scale polymers in space elevator technology

    NASA Astrophysics Data System (ADS)

    Knudsen, Steven; Golubovic, Leonardo

    Prospects to build Space Elevator (SE) systems have become realistic with ultra-strong materials such as carbon nano-tubes and diamond nano-threads. At cosmic length-scales, space elevators can be modeled as polymer like floppy strings of tethered mass beads. A new venue in SE science has emerged with the introduction of the Rotating Space Elevator (RSE) concept supported by novel algorithms discussed in this presentation. An RSE is a loopy string reaching into outer space. Unlike the classical geostationary SE concepts of Tsiolkovsky, Artsutanov, and Pearson, our RSE exhibits an internal rotation. Thanks to this, objects sliding along the RSE loop spontaneously oscillate between two turning points, one of which is close to the Earth whereas the other one is in outer space. The RSE concept thus solves a major problem in SE technology which is how to supply energy to the climbers moving along space elevator strings. The investigation of the classical and statistical mechanics of a floppy string interacting with objects sliding along it required development of subtle computational algorithms described in this presentation

  13. Transition path sampling with quantum/classical mechanics for reaction rates.

    PubMed

    Gräter, Frauke; Li, Wenjin

    2015-01-01

    Predicting rates of biochemical reactions through molecular simulations poses a particular challenge for two reasons. First, the process involves bond formation and/or cleavage and thus requires a quantum mechanical (QM) treatment of the reaction center, which can be combined with a more efficient molecular mechanical (MM) description for the remainder of the system, resulting in a QM/MM approach. Second, reaction time scales are typically many orders of magnitude larger than the (sub-)nanosecond scale accessible by QM/MM simulations. Transition path sampling (TPS) allows to efficiently sample the space of dynamic trajectories from the reactant to the product state without an additional biasing potential. We outline here the application of TPS and QM/MM to calculate rates for biochemical reactions, by means of a simple toy system. In a step-by-step protocol, we specifically refer to our implementation within the MD suite Gromacs, which we have made available to the research community, and include practical advice on the choice of parameters.

  14. Point-source idealization in classical field theories. II. Mechanical energy losses from electromagnetic radiation reaction

    NASA Astrophysics Data System (ADS)

    Kates, Ronald E.; Rosenblum, Arnold

    1982-05-01

    This paper compares the mechanical energy losses due to electromagnetic radiation reaction on a two-particle, slow-motion system, as calculated from (1) the method of matched asymptotic expansions and (2) the Lorentz-Dirac equation, which assumes point sources. The matching derivation of the preceding paper avoided the assumption of a δ-function source by using Reissner-Nordström matching zones. Despite the differing mathematical assumptions of the two methods, their results are in agreement with each other and with the electromagnetic-field energy losses calculated by the evaluation of flux integrals. Our purpose is eventually to analyze Rosenblum's use of point sources as a possible cause of disagreement between the analogous calculations of gravitational radiation on a slow-motion system of two bodies. We begin with the simpler electromagnetic problem.

  15. A witnessed case of a classic metaphyseal fracture caused during IV line placement in a child: Insight into mechanism of injury.

    PubMed

    Burrell, Tanya; Opfer, Erin; Berglund, Lisa; Lowe, Lisa H; Anderst, James

    2015-10-01

    Recent publications argue that classic metaphyseal fractures are caused by rickets as opposed to trauma. Previous case reports of accidental traumatic classic metaphyseal fractures have been discounted due to lack of identification of the fracture at the time of the traumatic event, and lack of an evaluation for boney metabolic disorders. We report a case of a 20 day old male with a diagnosis of congenital vertical talus who sustained a classic metaphyseal fracture of the distal tibia during manipulation in preparation for intravenous line placement. The mechanics of the event causing the classic metaphyseal fracture were witnessed and accompanied by an audible "pop". Prior x-rays of the tibia demonstrate normal osseous morphology, and an evaluation for boney metabolic disorders was normal. This case identifies a traumatic classic metaphyseal fracture and provides insight into the types of forces necessary to cause such a fracture.

  16. Classical molecular dynamics and ab initio simulations of chemical-mechanical polishing of amorphous silica

    NASA Astrophysics Data System (ADS)

    Chagarov, Evgueni Anatolievich

    Chemical-mechanical polishing (CMP) is a widely accepted process in the semiconductor industry. Despite intense theoretical and experimental research on CMP, there is a serious lack of fundamental understanding of the physical-chemical processes of polishing. The present work is intended to investigate these fundamental processes on an atomistic level. To model CMP on the atomic scale, a model of the amorphous silica is prepared by applying Design of Experiments (DOE) techniques to systematically investigate molecular dynamics preparation. These simulations yield high-quality models of amorphous silica, which are in excellent agreement with experimental results and are defect-free. Molecular dynamics simulations are performed to investigate the mechanical deformation during CMP of silica for different geometries and relative velocities. The simulations clarify asperity shape evolution during the process of shear and reveal temperature distributions as a function of time. It is found that the ratio of radii of a particle and asperity strongly affects the amount of the material removed whereas the relative velocity has a weaker affect on it. During shear, a significant local temperature increase occurs. This temperature increase lasts for a short time (picoseconds), but it can have a major impact on the amount of material removed. It is found that there could be significant deposition of the material from the particle to the slab, which can fill surface trenches and thereby make the surface smoother. An analytic model is developed for describing the amount of material removed as a function of asperity and particle radii and relative velocity. Density-functional calculations of different surfaces of two silica polymorphs, alpha-quartz and beta-cristobalite, are performed. The surface energies are calculated as a function of oxygen partial pressure for several different surface reconstructions and terminations. The case of hydrogen passivation is investigated to

  17. The study of oriented aggregation: A non-classical nanocrystal growth mechanism

    NASA Astrophysics Data System (ADS)

    Burrows, Nathan Dennis

    Oriented aggregation is a nonclassical crystal growth mechanism resulting in new secondary nanoparticles composed of crystallographically aligned primary crystallites. These secondary crystals often have unique and symmetry-defying morphologies, can be twinned, and can contain stacking faults and other significant defects. A wide range of important materials, such as titanium dioxide, iron oxides, selenides and sulfides, and metal oxyhydroxides, are known to grow by oriented aggregation under certain conditions. Evidence for oriented aggregation also has been observed in natural materials. However questions remain about what conditions are the most importing in facilitating purposeful control over nanoparticle size, size distribution, and morphology. Kinetic models for oriented aggregation point to important variables such as ionic strength, pH, temperature, and choice of dispersing solvent as being the key or keys to gaining control of this natural phenomenon and moving it towards a tool to be used in designing novel nanomaterials. The main technique used in this research is transmission electron microscopy with temporal resolution to characterize the population of growing nanocrystals. Cryogenic transmission electron microscopy is employed to observe the various stages of crystal growth. With extensive image analysis, it is possible to determine the kinetics of growth and the effects of systematically changing these key growth conditions. Additional complimentary techniques are employed, such as dynamic light scattering as well as various methods of characterization, such as powder X-ray diffraction. As our fundamental understanding of oriented aggregation improves, novel and complex functional materials are expected to emerge.

  18. Another Look at the Mechanisms of Hydride Transfer Enzymes from Quantum and Classical Transition Path Sampling

    NASA Astrophysics Data System (ADS)

    Dzierlenga, Michael; Antoniou, Dimitri; Schwartz, Steven

    2015-03-01

    The mechanisms involved in enzymatic hydride transfer have been studies for years but questions remain, due to the difficulty in determining the participation of protein dynamics and quantum effects, especially hydrogen tunneling. In this study, we use transition path sampling (TPS) with normal mode centroid molecular dynamics (CMD) to calculate the barrier to hydride transfer in yeast alcohol dehydrogenase (YADH) and lactate dehydrogenase (LDH). Calculation of the work applied to the hydride during the reaction allows for observation of the change in barrier height due to inclusion of quantum effects. Additionally, the same calculations were performed using deuterium as the transferring particle to validate our methods with experimentally measured kinetic isotope effects. The change in barrier height in YADH upon inclusion of quantum effects is indicative of a zero-point energy contribution, and is evidence that the protein mediates a near-barrierless transfer of the rate-limiting hydride. Calculation of kinetic isotope effects using the average difference in barrier between hydride and deuteride agreed well with experimental results. The authors acknowledge the support of the National Institutes of Health Grants GM068036 and GM102226.

  19. Immune-Regulatory Mechanisms of Classical and Experimental Multiple Sclerosis Drugs: A Special Focus on Helminth-Derived Treatments.

    PubMed

    Peón, Alberto N; Terrazas, Luis I

    2016-01-01

    Multiple sclerosis (MS) is the most prevalent autoimmune disease affecting the central nervous system (CNS). Its pathophysiology is centered on neuron myelin sheath destruction in a manner largely dependent upon CD4+/CD8+ T-cell autoreactivity against myelin antigens, inducing Th1/Th17 pathogenic responses with the resulting production of free radicals and soluble mediators that exhibit the effector mechanisms of neurodegeneration. The immune response responsible for this disease is complex and challenges modern medicine. Consequently, many experimental therapies have been proposed in addition to the classical array of immunoregulatory/ immunosuppressive drugs that are normally used to treat MS. In this review, we will describe the effects and mechanisms of action of widely used disease-modifying MS drugs as well as those of select treatments that are currently in the experimental phase. Special emphasis is placed on helminth-derived immunoregulators, as some of them have shown promising results. Additionally, we will compare the mechanisms of action of both the MS drugs and the helminth-derived treatments to discuss the potential importance of some signaling pathways in the control of MS.

  20. Understanding the reaction mechanism and intermediate stabilization in mammalian serine racemase using multiscale quantum-classical simulations.

    PubMed

    Nitoker, Neta; Major, Dan Thomas

    2015-01-20

    Serine racemase (SerR) is a pyridoxal-5'-phosphate (PLP)-dependent enzyme catalyzing the racemization of l-Ser to d-Ser. In mammals, d-Ser is an endogenous coagonist required for the activation of N-methyl-d-aspartate receptors (NMDARs), thus making SerR a promising pharmaceutical target. However, mechanistic studies of SerR are scarce, and the details of the enzymatic racemization reaction are not fully understood. In the current study we elucidate the catalytic mechanism in SerR by employing combined multiscale classical/quantum simulations. The free energy profile of a model SerR racemization reaction is first calculated in the gas phase and in aqueous solution. To obtain the free energy profile for the enzymatic reaction, hybrid quantum mechanics/molecular mechanics molecular dynamics simulations in conjunction with umbrella sampling are performed. The results suggest that in SerR, similarly to the related enzyme alanine racemase, the unprotonated PLP-substrate intermediate is stabilized mostly due to solvation effects contributed by water molecules and active-site residues, as well as long-range electrostatic interactions with the enzyme environment. In addition to a deeper understanding of the racemization mechanism in SerR, based on our simulations we propose specific mutations, which might shift the SerR equilibrium in favor of either l-Ser or d-Ser. Finally, the current studies have produced catalytically competent forms of the rat and human enzymes, which may serve as targets for future docking studies and drug design.

  1. Atypical manifestations of tinea corporis.

    PubMed

    Ziemer, Mirjana; Seyfarth, Florian; Elsner, Peter; Hipler, Uta-Christina

    2007-01-01

    Tinea corporis classically presents as an erythematous annular plaque with a scaly, centrifugally advancing border. However, sometimes vesicles and pustules are observed. Occasionally, even frank bullae appear secondary to severe inflammation. Diagnostic difficulties arise when atypical manifestations mimic other inflammatory skin diseases, including atopic or seborrheic dermatitis, subacute cutaneous lupus erythematosus, or vesicular diseases. We report five cases of atypical tinea corporis, where the initial clinical diagnosis was different from dermatophytosis. The differential diagnoses and the diagnostic difficulties related to atypical manifestations of fungal infections are discussed. Moreover, our cases emphasise the importance of conventional histological examination, which enables a fast, correct diagnosis.

  2. Combined quantum mechanics (TDDFT) and classical electrodynamics (Mie theory) methods for calculating surface enhanced Raman and hyper-Raman spectra.

    PubMed

    Mullin, Jonathan; Valley, Nicholas; Blaber, Martin G; Schatz, George C

    2012-09-27

    Multiscale models that combine quantum mechanics and classical electrodynamics are presented, which allow for the evaluation of surface-enhanced Raman (SERS) and hyper-Raman scattering spectra (SEHRS) for both chemical (CHEM) and electrodynamic (EM) enhancement mechanisms. In these models, time-dependent density functional theory (TDDFT) for a system consisting of the adsorbed molecule and a metal cluster fragment of the metal particle is coupled to Mie theory for the metal particle, with the surface of the cluster being overlaid with the surface of the metal particle. In model A, the electromagnetic enhancement from plasmon-excitation of the metal particle is combined with the chemical enhancement associated with a static treatment of the molecule-metal structure to determine overall spectra. In model B, the frequency dependence of the Raman spectrum of the isolated molecule is combined with the enhancements determined in model A to refine the enhancement estimate. An equivalent theory at the level of model A is developed for hyper-Raman spectra calculations. Application to pyridine interacting with a 20 nm diameter silver sphere is presented, including comparisons with an earlier model (denoted G), which combines plasmon enhanced fields with gas-phase Raman (or hyper-Raman) spectra. The EM enhancement factor for spherical particles at 357 nm is found to be 10(4) and 10(6) for SERS and SEHRS, respectively. Including both chemical and electromagnetic mechanisms at the level of model A leads to enhancements on the order of 10(4) and 10(9) for SERS and SEHRS.

  3. RNA sequencing reveals region-specific molecular mechanisms associated with epileptogenesis in a model of classical hippocampal sclerosis

    PubMed Central

    Vieira, A. S.; de Matos, A. H.; do Canto, A. M.; Rocha, C. S.; Carvalho, B. S.; Pascoal, V. D. B.; Norwood, B.; Bauer, S.; Rosenow, F.; Gilioli, R.; Cendes, F.; Lopes-Cendes, I.

    2016-01-01

    We report here the first complete transcriptome analysis of the dorsal (dDG) and ventral dentate gyrus (vDG) of a rat epilepsy model presenting a hippocampal lesion with a strict resemblance to classical hippocampal sclerosis (HS). We collected the dDG and vDG by laser microdissection 15 days after electrical stimulation and performed high-throughput RNA-sequencing. There were many differentially regulated genes, some of which were specific to either of the two sub-regions in stimulated animals. Gene ontology analysis indicated an enrichment of inflammation-related processes in both sub-regions and of axonal guidance and calcium signaling processes exclusively in the vDG. There was also a differential regulation of genes encoding molecules involved in synaptic function, neural electrical activity and neuropeptides in stimulated rats. The data presented here suggests, in the time point analyzed, a remarkable interaction among several molecular components which takes place in the damaged hippocampi. Furthermore, even though similar mechanisms may function in different regions of the DG, the molecular components involved seem to be region specific. PMID:26935982

  4. Computational methods in the exploration of the classical and statistical mechanics of celestial scale strings: Rotating Space Elevators

    NASA Astrophysics Data System (ADS)

    Knudsen, Steven; Golubovic, Leonardo

    2015-04-01

    With the advent of ultra-strong materials, the Space Elevator has changed from science fiction to real science. We discuss computational and theoretical methods we developed to explore classical and statistical mechanics of rotating Space Elevators (RSE). An RSE is a loopy string reaching deep into outer space. The floppy RSE loop executes a motion which is nearly a superposition of two rotations: geosynchronous rotation around the Earth, and yet another faster rotational motion of the string which goes on around a line perpendicular to the Earth at its equator. Strikingly, objects sliding along the RSE loop spontaneously oscillate between two turning points, one of which is close to the Earth (starting point) whereas the other one is deeply in the outer space. The RSE concept thus solves a major problem in space elevator science which is how to supply energy to the climbers moving along space elevator strings. The exploration of the dynamics of a floppy string interacting with objects sliding along it has required development of novel finite element algorithms described in this presentation. We thank Prof. Duncan Lorimer of WVU for kindly providing us access to his computational facility.

  5. Combining classical molecular dynamics and quantum mechanical methods for the description of electronic excitations: The case of carotenoids.

    PubMed

    Prandi, Ingrid G; Viani, Lucas; Andreussi, Oliviero; Mennucci, Benedetta

    2016-04-30

    Carotenoids are important actors both in light-harvesting (LH) and in photoprotection functions of photosynthetic pigment-protein complexes. A deep theoretical investigation of this multiple role is still missing owing to the difficulty of describing the delicate interplay between electronic and nuclear degrees of freedom. A possible strategy is to combine accurate quantum mechanical (QM) methods with classical molecular dynamics. To do this, however, accurate force-fields (FF) are necessary. This article presents a new FF for the different carotenoids present in LH complexes of plants. The results show that all the important structural properties described by the new FF are in very good agreement with QM reference values. This increased accuracy in the simulation of the structural fluctuations is also reflected in the description of excited states. Both the energy order and the different nature of the lowest singlet states are preserved during the dynamics when the new FF is used, whereas an unphysical mixing is found when a standard FF is used.

  6. Non-classical mechanism of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor channel block by fluoxetine.

    PubMed

    Barygin, Oleg I; Komarova, Margarita S; Tikhonova, Tatiana B; Tikhonov, Denis B

    2015-04-01

    Antidepressants have many targets in the central nervous system. A growing body of data demonstrates the influence of antidepressants on glutamatergic neurotransmission. In the present work, we studied the inhibition of native Ca(2+)-permeable and Ca(2+)-impermeable α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors in rat brain neurons by fluoxetine. The Ca(2+)-impermeable AMPA receptors in CA1 hippocampal pyramidal neurons were weakly affected. The IC50 value for the inhibition of Ca(2+)-permeable AMPA receptors in giant striatal interneurons was 43 ± 7 μM. The inhibition of Ca(2+)-permeable AMPA receptors was voltage dependent, suggesting deep binding in the pore. However, the use dependence of fluoxetine action differed markedly from that of classical AMPA receptor open-channel blockers. Moreover, fluoxetine did not compete with other channel blockers. In contrast to fluoxetine, its membrane-impermeant quaternary analog demonstrated all of the features of channel inhibition typical for open-channel blockers. It is suggested that fluoxetine reaches the binding site through a hydrophobic access pathway. Such a mechanism of block is described for ligands of sodium and calcium channels, but was never found in AMPA receptors. Molecular modeling suggests binding of fluoxetine in the subunit interface; analogous binding was proposed for local anesthetics in closed sodium channels and for benzothiazepines in calcium channels.

  7. Classical Electrodynamics Coupled to Quantum Mechanics for Calculation of Molecular Optical Properties: a RT-TDDFT/FDTD Approach

    SciTech Connect

    Chen, Hanning; McMahon, J. M.; Ratner, Mark A.; Schatz, George C.

    2010-09-02

    A new multiscale computational methodology was developed to effectively incorporate the scattered electric field of a plasmonic nanoparticle into a quantum mechanical (QM) optical property calculation for a nearby dye molecule. For a given location of the dye molecule with respect to the nanoparticle, a frequency-dependent scattering response function was first determined by the classical electrodynamics (ED) finite-difference time-domain (FDTD) approach. Subsequently, the time-dependent scattered electric field at the dye molecule was calculated using the FDTD scattering response function through a multidimensional Fourier transform to reflect the effect of polarization of the nanoparticle on the local field at the molecule. Finally, a real-time time-dependent density function theory (RT-TDDFT) approach was employed to obtain a desired optical property (such as absorption cross section) of the dye molecule in the presence of the nanoparticle’s scattered electric field. Our hybrid QM/ED methodology was demonstrated by investigating the absorption spectrum of the N3 dye molecule and the Raman spectrum of pyridine, both of which were shown to be significantly enhanced by a 20 nm diameter silver sphere. In contrast to traditional quantum mechanical optical calculations in which the field at the molecule is entirely determined by intensity and polarization direction of the incident light, in this work we show that the light propagation direction as well as polarization and intensity are important to nanoparticle-bound dye molecule response. At no additional computation cost compared to conventional ED and QM calculations, this method provides a reliable way to couple the response of the dye molecule’s individual electrons to the collective dielectric response of the nanoparticle.

  8. Interfacing ab initio Quantum Mechanical Method with Classical Drude Osillator Polarizable Model for Molecular Dynamics Simulation of Chemical Reactions

    PubMed Central

    Lu, Zhenyu; Zhang, Yingkai

    2009-01-01

    In order to further improve the accuracy and applicability of combined quantum mechanical/molecular mechanical (QM/MM) methods, we have interfaced the ab initio QM method with the classical Drude oscillator polarizable MM force field (ai-QM/MM-Drude). Different coupling approaches have been employed and compared: 1. the conventional dual self-consistent-field (SCF) procedure; 2. the direct SCF scheme, in which QM densities and MM Drude positions are converged simultaneously; 3. the micro-iterative SCF scheme, in which the Drude positions of the polarizable model are fully converged during each self-consistent field (SCF) step of QM calculations; 4. the one-step-Drude-update scheme, in which the MM Drude positions are updated only once instead of fully converged during each molecular dynamics (MD) step. The last three coupling approaches are found to be efficient and can achieve the desired convergence in a similar number of QM SCF steps comparing with the corresponding QM method coupled to a non-polarizable force field. The feasibility and applicability of the implemented ai-QM/MM-Drude approach have been demonstrated by carrying out Born-Oppenheimer molecular dynamics simulations with the umbrella sampling method to determine potentials of mean force for both the methyl transfer reaction of the methyl chlorine-chlorine ion system and the glycine intra-molecular proton transfer reaction in aqueous solution. Our results indicate that the ai-QM/MM-Drude approach is very promising, which provides a better description of QM/MM interactions while can achieve quite similar computational efficiency in comparison with the corresponding conventional ab initio QM/MM method. PMID:19221605

  9. Understanding the Mechanism of Human P450 CYP1A2 Using Coupled Quantum-Classical Simulations in a Dynamical Environment

    SciTech Connect

    Draeger, E W; Bennion, B; Gygi, F; Lightstone, F

    2006-02-10

    The reaction mechanism of the human P450 CYP1A2 enzyme plays a fundamental role in understanding the effects of environmental carcinogens and mutagens on humans. Despite extensive experimental research on this enzyme system, key questions regarding its catalytic cycle and oxygen activation mechanism remain unanswered. In order to elucidate the reaction mechanism in human P450, new computational methods are needed to accurately represent this system. To enable us to perform computational simulations of unprecedented accuracy on these systems, we developed a dynamic quantum-classical (QM/MM) hybrid method, in which ab initio molecular dynamics are coupled with classical molecular mechanics. This will provide the accuracy needed to address such a complex, large biological system in a fully dynamic environment. We also present detailed calculations of the P450 active site, including the relative charge transfer between iron porphine and tetraphenyl porphyrin.

  10. Cutaneous Manifestations of Crohn Disease.

    PubMed

    Hagen, Joshua W; Swoger, Jason M; Grandinetti, Lisa M

    2015-07-01

    Awareness of the extraintestinal manifestations of Crohn disease is increasing in dermatology and gastroenterology, with enhanced identification of entities that range from granulomatous diseases recapitulating the underlying inflammatory bowel disease to reactive conditions and associated dermatoses. In this review, the underlying etiopathology of Crohn disease is discussed, and how this mirrors certain skin manifestations that present in a subset of patients is explored. The array of extraintestinal manifestations that do not share a similar pathology, but which are often seen in association with inflammatory bowel disease, is also discussed. Treatment and pathogenetic mechanisms, where available, are discussed.

  11. Lewis pair polymerization by classical and frustrated Lewis pairs: acid, base and monomer scope and polymerization mechanism.

    PubMed

    Zhang, Yuetao; Miyake, Garret M; John, Mallory G; Falivene, Laura; Caporaso, Lucia; Cavallo, Luigi; Chen, Eugene Y-X

    2012-08-14

    Classical and frustrated Lewis pairs (LPs) of the strong Lewis acid (LA) Al(C(6)F(5))(3) with several Lewis base (LB) classes have been found to exhibit exceptional activity in the Lewis pair polymerization (LPP) of conjugated polar alkenes such as methyl methacrylate (MMA) as well as renewable α-methylene-γ-butyrolactone (MBL) and γ-methyl-α-methylene-γ-butyrolactone (γ-MMBL), leading to high molecular weight polymers, often with narrow molecular weight distributions. This study has investigated a large number of LPs, consisting of 11 LAs as well as 10 achiral and 4 chiral LBs, for LPP of 12 monomers of several different types. Although some more common LAs can also be utilized for LPP, Al(C(6)F(5))(3)-based LPs are far more active and effective than other LA-based LPs. On the other hand, several classes of LBs, when paired with Al(C(6)F(5))(3), can render highly active and effective LPP of MMA and γ-MMBL; such LBs include phosphines (e.g., P(t)Bu(3)), chiral chelating diphosphines, N-heterocyclic carbenes (NHCs), and phosphazene superbases (e.g., P(4)-(t)Bu). The P(4)-(t)Bu/Al(C(6)F(5))(3) pair exhibits the highest activity of the LP series, with a remarkably high turn-over frequency of 9.6 × 10(4) h(-1) (0.125 mol% catalyst, 100% MMA conversion in 30 s, M(n) = 2.12 × 10(5) g mol(-1), PDI = 1.34). The polymers produced by LPs at RT are typically atactic (P(γ)MMBL with ∼47% mr) or syndio-rich (PMMA with ∼70-75% rr), but highly syndiotactic PMMA with rr ∼91% can be produced by chiral or achiral LPs at -78 °C. Mechanistic studies have identified and structurally characterized zwitterionic phosphonium and imidazolium enolaluminates as the active species of the current LPP system, which are formed by the reaction of the monomer·Al(C(6)F(5))(3) adduct with P(t)Bu(3) and NHC bases, respectively. Kinetic studies have revealed that the MMA polymerization by the (t)Bu(3)P/Al(C(6)F(5))(3) pair is zero-order in monomer concentration after an initial

  12. Classics Online.

    ERIC Educational Resources Information Center

    Clayman, Dee L.

    1995-01-01

    Appraises several databases devoted to classical literature. Thesaurus Linguae Graecae (TLG) contains the entire extant corpus of ancient Greek literature, including works on lexicography and historiography, extending into the 15th century. Other works awaiting completion are the Database of Classical Bibliography and a CD-ROM pictorial dictionary…

  13. Classical integrability

    NASA Astrophysics Data System (ADS)

    Torrielli, Alessandro

    2016-08-01

    We review some essential aspects of classically integrable systems. The detailed outline of the sections consists of: 1. Introduction and motivation, with historical remarks; 2. Liouville theorem and action-angle variables, with examples (harmonic oscillator, Kepler problem); 3. Algebraic tools: Lax pairs, monodromy and transfer matrices, classical r-matrices and exchange relations, non-ultralocal Poisson brackets, with examples (non-linear Schrödinger model, principal chiral field); 4. Features of classical r-matrices: Belavin-Drinfeld theorems, analyticity properties, and lift of the classical structures to quantum groups; 5. Classical inverse scattering method to solve integrable differential equations: soliton solutions, spectral properties and the Gel’fand-Levitan-Marchenko equation, with examples (KdV equation, Sine-Gordon model). Prepared for the Durham Young Researchers Integrability School, organised by the GATIS network. This is part of a collection of lecture notes.

  14. Atypical Cutaneous Manifestations in Syphilis.

    PubMed

    Ivars Lleó, M; Clavo Escribano, P; Menéndez Prieto, B

    2016-05-01

    Although the diversity of the clinical manifestations of syphilis is well-known, atypical presentations can also occur. Such atypical presentations are associated with a high risk of transmission as a result of diagnostic confusion and treatment delays owing to the disease's ability to mimic other common skin diseases, deviate from classic clinical presentations, and adopt unique forms. Cases of atypical syphilis have been described most frequently in patients with concomitant human immunodeficiency virus (HIV) infection. Because the incidence of syphilis has been growing over recent years -particularly in patients with HIV co-infection- dermatologists need to be familiar with the less well-known clinical presentations of this venereal disease.

  15. The classical Bloch equations

    NASA Astrophysics Data System (ADS)

    Frimmer, Martin; Novotny, Lukas

    2014-10-01

    Coherent control of a quantum mechanical two-level system is at the heart of magnetic resonance imaging, quantum information processing, and quantum optics. Among the most prominent phenomena in quantum coherent control are Rabi oscillations, Ramsey fringes, and Hahn echoes. We demonstrate that these phenomena can be derived classically by use of a simple coupled-harmonic-oscillator model. The classical problem can be cast in a form that is formally equivalent to the quantum mechanical Bloch equations with the exception that the longitudinal and the transverse relaxation times (T1 and T2) are equal. The classical analysis is intuitive and well suited for familiarizing students with the basic concepts of quantum coherent control, while at the same time highlighting the fundamental differences between classical and quantum theories.

  16. Classical confined particles

    NASA Technical Reports Server (NTRS)

    Horzela, Andrzej; Kapuscik, Edward

    1993-01-01

    An alternative picture of classical many body mechanics is proposed. In this picture particles possess individual kinematics but are deprived from individual dynamics. Dynamics exists only for the many particle system as a whole. The theory is complete and allows to determine the trajectories of each particle. It is proposed to use our picture as a classical prototype for a realistic theory of confined particles.

  17. Quantum mechanics as a classical theory-application to the interaction of light with an extremely diluted gas: redshifts and black matter in astrophysics.

    NASA Astrophysics Data System (ADS)

    Moret-Bailly, J.

    In the study of experiments of laser spectroscopy, there appears a convergence of the methods of quantum electrodynamics and classical optics: for instance stochastic electrodynamics used for the study of "squeezed states" is common to both theories, and the quantum coherent states are almost classical states. The author shows that this convergence allows to explain the paradoxes of quantum mechanics. The interaction of ultrashort laser pulses with ordinary matter is equivalent to the interaction of incoherent light with extremely dilute gases. Thus, the interaction of light from stars with cosmic gas produces a redshift similar to the Doppler redshift. In a very low pressure gas, the absorption of incoherent light disappears completely, so that the "black matter" could be simply H2 and its products of decomposition by high-frequency radiation.

  18. Cutaneous manifestations in celiac disease

    PubMed Central

    Abenavoli, L; Proietti, I; Leggio, L; Ferrulli, A; Vonghia, L; Capizzi, R; Rotoli, M; Amerio, PL; Gasbarrini, G; Addolorato, G

    2006-01-01

    Celiac disease (CD) is an autoimmune gluten-dependent enteropathy characterized by atrophy of intestinal villi that improves after gluten-free diet (GFD). CD is often associated with extra-intestinal manifestations; among them, several skin diseases are described in CD patients. The present review reports all CD-associated skin manifestations described in the literature and tries to analyze the possible mechanisms involved in this association. The opportunity to evaluate the possible presence of CD in patients affected by skin disorders is discussed. PMID:16521210

  19. Classical Novae

    NASA Astrophysics Data System (ADS)

    Bode, Michael F.; Evans, Aneurin

    2012-07-01

    Preface; 1. Novae - a historical perspective Hilmar W. Duerbeck; 2. Properties of novae: an overview Brian Warner; 3. The evolution of nova-producing binary stars Icko Iben, Jr and Masayuki Y. Fujimoto; 4. Thermonuclear processes S. Starrfield, C. Iliadis and W. R. Hix; 5. Nova atmospheres and winds P. H. Hauschildt; 6. Observational mysteries and theoretical challenges Jordi Jose and Steven N. Shore; 7. Radio emission from novae E. R. Seaquist and M. F. Bode; 8. Infrared studies of classical novae Robert D. Gehrz; 9. Optical and ultraviolet evolution Steven N. Shore; 10. X-ray emission from classical novae in outburst Joachim Krautter; 11. Gamma-rays from classical novae Margarita Hernanz; 12. Resolved nova remnants T. J. O'Brien and M. F. Bode; 13. Dust and molecules in nova environments A. Evans and J. M. C. Rawlings; 14. Extragalactic novae Allen Shafter; Index.

  20. Mixed quantum-classical molecular dynamics analysis of the molecular-level mechanisms of vibrational frequency shifts.

    PubMed

    Morales, Christine M; Thompson, Ward H

    2007-06-28

    A detailed analysis of the origins of vibrational frequency shifts of diatomic molecules (I2 and ICl) in a rare gas (Xe) liquid is presented. Specifically, vibrationally adiabatic mixed quantum-classical molecular dynamics simulations are used to obtain the instantaneous frequency shifts and correlate the shifts to solvent configurations. With this approach, important mechanistic questions are addressed, including the following: How many solvent atoms determine the frequency shift? What solvent atom configurations lead to blue shifts, and which lead to red shifts? What is the effect of solute asymmetry? The mechanistic analysis can be generally applied and should be useful in understanding what information is provided by infrared and Raman spectra about the environment of the probed vibrational mode.

  1. Hyperangular momenta and energy partitions in multidimensional many-particle classical mechanics: The invariance approach to cluster dynamics

    SciTech Connect

    Sevryuk, Mikhail B.; Lombardi, Andrea; Aquilanti, Vincenzo

    2005-09-15

    Rigorous and complete definitions of two partitions and one expansion for the kinetic energy of a general N-particle classical system are given. Our recent work, which also provides examples of applications to the molecular dynamics of nanoaggregates, based on computer programs formulated on the basis of the theory presented here, is extended to cover arbitrary physical space dimensions. The partitions and the expansion are in terms of quantities conceived to be instantaneous phase-space invariants - a far-reaching generalization of integrals of the motion. These quantities are introduced setting out as starting points the position matrix Z of the system and the time derivative of Z. In the simplest case, the matrix Z contains the mass-scaled Cartesian coordinates of the N particles. From the position matrix, the kinematic rotations naturally arise through orthogonal transformations, as a concept 'dual' to the ordinary physical rotations. The physical meaning of each partition (expansion) term is clearly described and emphasized, and formulas for the various quantities are provided as well as inequalities among them. Proofs are presented making extensive use of the singular value decomposition (SVD) of matrices and of the signed SVD, an extended version overcoming possible singularities for particular values of N.

  2. Perspective: Quantum or classical coherence?

    PubMed

    Miller, William H

    2012-06-07

    Some coherence effects in chemical dynamics are described correctly by classical mechanics, while others only appear in a quantum treatment--and when these are observed experimentally it is not always immediately obvious whether their origin is classical or quantum. Semiclassical theory provides a systematic way of adding quantum coherence to classical molecular dynamics and thus provides a useful way to distinguish between classical and quantum coherence. Several examples are discussed which illustrate both cases. Particularly interesting is the situation with electronically non-adiabatic processes, where sometimes whether the coherence effects are classical or quantum depends on what specific aspects of the process are observed.

  3. Rheumatic manifestations of scurvy.

    PubMed

    Ferrari, Claudia; Possemato, Niccolò; Pipitone, Nicolò; Manger, Bernhard; Salvarani, Carlo

    2015-04-01

    This paper reviews the rheumatological manifestations of scurvy, based on articles published in English from 1965 until October 2014, with a particular focus on rheumatological manifestations. Scurvy is a rare, uncommon disease in developed countries. Due to its clinical heterogeneity, the disease can easily mimic rheumatologic conditions leading to a delay in diagnosis and treatment.

  4. [Cutaneous manifestations of sarcoidosis].

    PubMed

    Amschler, K; Seitz, C S

    2017-03-17

    Skin manifestations of sarcoidosis occur in up to 30% of cases. This review summarizes and illustrates in detail the differences between specific and unspecific skin manifestations of sarcoidosis. Important differential diagnoses, such as tuberculosis, cutaneous lymphoma and syphilis have to be excluded. The indications for systemic treatment are primarily determined by the extent of organ involvement and also by the cosmetic impairment.

  5. InGaAs tunnel diodes for the calibration of semi-classical and quantum mechanical band-to-band tunneling models

    SciTech Connect

    Smets, Quentin; Verreck, Devin; Vandervorst, Wilfried; Groeseneken, Guido; Heyns, Marc M.; Verhulst, Anne S.; Rooyackers, Rita; Merckling, Clément; Simoen, Eddy; Collaert, Nadine; Thean, Voon Y.; Van De Put, Maarten; Sorée, Bart

    2014-05-14

    Promising predictions are made for III-V tunnel-field-effect transistor (FET), but there is still uncertainty on the parameters used in the band-to-band tunneling models. Therefore, two simulators are calibrated in this paper; the first one uses a semi-classical tunneling model based on Kane's formalism, and the second one is a quantum mechanical simulator implemented with an envelope function formalism. The calibration is done for In{sub 0.53}Ga{sub 0.47}As using several p+/intrinsic/n+ diodes with different intrinsic region thicknesses. The dopant profile is determined by SIMS and capacitance-voltage measurements. Error bars are used based on statistical and systematic uncertainties in the measurement techniques. The obtained parameters are in close agreement with theoretically predicted values and validate the semi-classical and quantum mechanical models. Finally, the models are applied to predict the input characteristics of In{sub 0.53}Ga{sub 0.47}As n- and p-lineTFET, with the n-lineTFET showing competitive performance compared to MOSFET.

  6. Genital manifestations of tropical diseases

    PubMed Central

    Richens, J

    2004-01-01

    Genital symptoms in tropical countries and among returned travellers can arise from a variety of bacterial, protozoal, and helminthic infections which are not usually sexually transmitted. The symptoms may mimic classic sexually transmitted infections (STIs) by producing ulceration (for example, amoebiasis, leishmaniasis), wart-like lesions (schistosomiasis), or lesions of the upper genital tract (epididymo-orchitis caused by tuberculosis, leprosy, and brucellosis; salpingitis as a result of tuberculosis, amoebiasis, and schistosomiasis). A variety of other genital symptoms less suggestive of STI are also seen in tropical countries. These include hydrocele (seen with filariasis), which can be no less stigmatising than STI, haemospermia (seen with schistosomiasis), and hypogonadism (which may occur in lepromatous leprosy). This article deals in turn with genital manifestations of filariasis, schistosomiasis, amoebiasis, leishmaniasis, tuberculosis and leprosy and gives clinical presentation, diagnosis, and treatment. PMID:14755029

  7. NMR lineshape equations for hindered methyl group: a comparison of the semi-classical and quantum mechanical models.

    PubMed

    Bernatowicz, P; Szymański, S

    2003-09-01

    The semiclassical and quantum mechanical NMR lineshape equations for a hindered methyl group are compared. In both the approaches, the stochastic dynamics can be interpreted in terms of a progressive symmetrization of the spin density matrix. However, the respective ways of achieving the same limiting symmetry can be remarkably different. From numerical lineshape simulations it is inferred that in the regime of intermediate exchange, where the conventional theory predicts occurrence of a single Lorentzian, the actual spectrum can have nontrivial features. This observation may open new perspectives in the search for nonclassical effects in the stochastic behavior of methyl groups in liquid-phase NMR.

  8. Prediction of anomalous diffusion and algebraic relaxations for long-range interacting systems, using classical statistical mechanics.

    PubMed

    Bouchet, Freddy; Dauxois, Thierry

    2005-10-01

    We explain the ubiquity and extremely slow evolution of non-Gaussian out-of-equilibrium distributions for the Hamiltonian mean-field model, by means of traditional kinetic theory. Deriving the Fokker-Planck equation for a test particle, one also unambiguously explains and predicts striking slow algebraic relaxation of the momenta autocorrelation, previously found in numerical simulations. Finally, angular anomalous diffusion are predicted for a large class of initial distributions. Non-extensive statistical mechanics is shown to be unnecessary for the interpretation of these phenomena.

  9. Complementarity between Quantum and Classical Mechanics in Chemical Modeling. The H + HeH+ → H2 + + He Reaction: A Rigourous Test for Reaction Dynamics Methods.

    PubMed

    Esposito, Fabrizio; Coppola, Carla Maria; De Fazio, Dario

    2015-12-24

    In this work we present a dynamical study of the H + HeH+ → H2+ + He reaction in a collision energy range from 0.1 meV to 10 eV, suitable to be used in applicative models. The paper extends and complements a recent work [ Phys. Chem. Chem. Phys. 2014, 16, 11662] devoted to the characterization of the reactivity from the ultracold regime up to the three-body dissociation breakup. In particular, the accuracy of the quasi-classical trajectory method below the three-body dissociation threshold has been assessed by a detailed comparison with previous calculations performed with different reaction dynamics methods, whereas the reliability of the results in the high energy range has been checked by a direct comparison with the available experimental data. Integral cross sections for several HeH+ roto-vibrational states have been analyzed and used to understand the extent of quantum effects in the reaction dynamics. By using the quasi-classical trajectory method and quantum mechanical close coupling data, respectively, in the high and low collision energy ranges, we obtain highly accurate thermal rate costants until 15 000 K including all (178) the roto-vibrational bound and quasi-bound states of HeH+. The role of the collision-induced dissociation is also discussed and explicitly calculated for the ground roto-vibrational state of HeH+.

  10. Structure, spectra, and rearrangement mechanism of PH2F3: revisiting a classic problem in structural inorganic chemistry.

    PubMed

    Villaume, Sébastien; Strich, Alain; Perera, S Ajith; Bartlett, Rodney J

    2007-03-22

    The structure, spectra, and rearrangement mechanisms of PH2F3, the first member of the PHnF5-n series and a prototype for molecules that undergo rotational isomerism, have been studied. Aided by the tools developed to compute coupled-cluster (CC) Raman intensities and NMR spin-spin couplings, a full spectroscopic characterization of PH2F3 is presented. Moreover, the structures and the energetics of the various stereoisomers are computed at the CC level (CCSD(T)) to assess the validity of proposed rearrangement mechanisms. While corroborating prior experimental IR and NMR assignments, the results are also able to remedy the "speculative" Raman and NMR assignments that lacked reliable computed values when the experiments were done. More importantly, the results identify "spectral fingerprints" that could distinguish various rotational isomers. These data, when used concurrently along with high resolution measurements, form a powerful basis for the characterization of various rotational isomers of PH2F3. A "new" stability diagram and a rearrangement path based on the computed energetic and structure data are obtained. That is far superior to what has been available in the literature.

  11. Ophthalmic manifestations of neurofibromatosis.

    PubMed Central

    Huson, S; Jones, D; Beck, L

    1987-01-01

    The eyes of 64 patients known to have neurofibromatosis were examined. Lisch nodules were the commonest manifestation of the disease and were present in 95% of all patients (100% of those aged 16 years or older). Images PMID:3103673

  12. Clinical manifestations of sleep apnea

    PubMed Central

    2015-01-01

    Obstructive sleep apnea (OSA) may manifest in a number of ways from subtle intrusion into daily life to profound sleepiness, snoring, witnessed apneas and other classic symptoms. Although there is increasing evidence suggesting OSA can adversely affect health in a variety of ways, this disorder remains underdiagnosed. The most well-escribed health consequences of OSA relate to the cardiovascular system. Hypertension and arrhythmias have a strong association with OSA, and evidence suggests that treatment of OSA in patients with refractory hypertension and in patients planning cardioversion for atrial fibrillation may be of particularly importance. Significant associations between heart failure and OSA as well as complex sleep apnea have also been well-described. Cerebrovascular insult, impaired neurocognition, and poorly controlled mood disorder are also associated with in OSA. Therapy for OSA may ameliorate atherosclerotic progression and improve outcomes post-cerebrovascular accident (CVA). OSA should be considered in patients complaining of poor concentration at work, actual or near-miss motor vehicle accidents, and patients with severe sleepiness as a component of their co-morbid mood disorders. The metabolic impact of OSA has also been studied, particularly in relation to glucose homeostasis. Also of interest is the potential impact OSA has on lipid metabolism. The adverse effect untreated OSA has on glucose tolerance and lipid levels has led to the suggestion that OSA is yet another constituent of the metabolic syndrome. Some of these metabolic derangements may be related to the adverse effects untreated OSA has on hepatic health. The cardiovascular, neurocognitive, and metabolic manifestations of OSA can have a significant impact on patient health and quality of life. In many instances, evidence exists that therapy not only improves outcomes in general, but also modifies the severity of co-morbid disease. To mitigate the long-term sequela of this disease

  13. Clinical manifestations of sleep apnea.

    PubMed

    Stansbury, Robert C; Strollo, Patrick J

    2015-09-01

    Obstructive sleep apnea (OSA) may manifest in a number of ways from subtle intrusion into daily life to profound sleepiness, snoring, witnessed apneas and other classic symptoms. Although there is increasing evidence suggesting OSA can adversely affect health in a variety of ways, this disorder remains underdiagnosed. The most well-escribed health consequences of OSA relate to the cardiovascular system. Hypertension and arrhythmias have a strong association with OSA, and evidence suggests that treatment of OSA in patients with refractory hypertension and in patients planning cardioversion for atrial fibrillation may be of particularly importance. Significant associations between heart failure and OSA as well as complex sleep apnea have also been well-described. Cerebrovascular insult, impaired neurocognition, and poorly controlled mood disorder are also associated with in OSA. Therapy for OSA may ameliorate atherosclerotic progression and improve outcomes post-cerebrovascular accident (CVA). OSA should be considered in patients complaining of poor concentration at work, actual or near-miss motor vehicle accidents, and patients with severe sleepiness as a component of their co-morbid mood disorders. The metabolic impact of OSA has also been studied, particularly in relation to glucose homeostasis. Also of interest is the potential impact OSA has on lipid metabolism. The adverse effect untreated OSA has on glucose tolerance and lipid levels has led to the suggestion that OSA is yet another constituent of the metabolic syndrome. Some of these metabolic derangements may be related to the adverse effects untreated OSA has on hepatic health. The cardiovascular, neurocognitive, and metabolic manifestations of OSA can have a significant impact on patient health and quality of life. In many instances, evidence exists that therapy not only improves outcomes in general, but also modifies the severity of co-morbid disease. To mitigate the long-term sequela of this disease

  14. Collaborative Simulation Grid: Multiscale Quantum-Mechanical/Classical Atomistic Simulations on Distributed PC Clusters in the US and Japan

    NASA Technical Reports Server (NTRS)

    Kikuchi, Hideaki; Kalia, Rajiv; Nakano, Aiichiro; Vashishta, Priya; Iyetomi, Hiroshi; Ogata, Shuji; Kouno, Takahisa; Shimojo, Fuyuki; Tsuruta, Kanji; Saini, Subhash; Biegel, Bryan (Technical Monitor)

    2002-01-01

    A multidisciplinary, collaborative simulation has been performed on a Grid of geographically distributed PC clusters. The multiscale simulation approach seamlessly combines i) atomistic simulation backed on the molecular dynamics (MD) method and ii) quantum mechanical (QM) calculation based on the density functional theory (DFT), so that accurate but less scalable computations are performed only where they are needed. The multiscale MD/QM simulation code has been Grid-enabled using i) a modular, additive hybridization scheme, ii) multiple QM clustering, and iii) computation/communication overlapping. The Gridified MD/QM simulation code has been used to study environmental effects of water molecules on fracture in silicon. A preliminary run of the code has achieved a parallel efficiency of 94% on 25 PCs distributed over 3 PC clusters in the US and Japan, and a larger test involving 154 processors on 5 distributed PC clusters is in progress.

  15. Rheumatologic manifestations of diabetes mellitus.

    PubMed

    Crispin, José C; Alcocer-Varela, Jorge

    2003-06-15

    Diabetes mellitus has been linked to disorders of bones and joints, including neuroarthropathy, limited joint mobility, and hyperostosis. Some of the relations have known pathogenic mechanisms, but most are based on epidemiologic findings. This article reviews the associations between diabetes mellitus and its putative rheumatologic manifestations, and proposes a classification composed of four categories: consequences of diabetic complications, consequences of metabolic derangements inherent to diabetes, syndromes that may share etiologic mechanisms with microvascular disease, and probable associations. This approach may facilitate a clearer understanding of the musculoskeletal conditions that are prevalent in patients with diabetes mellitus.

  16. Randomness: Quantum versus classical

    NASA Astrophysics Data System (ADS)

    Khrennikov, Andrei

    2016-05-01

    Recent tremendous development of quantum information theory has led to a number of quantum technological projects, e.g. quantum random generators. This development had stimulated a new wave of interest in quantum foundations. One of the most intriguing problems of quantum foundations is the elaboration of a consistent and commonly accepted interpretation of a quantum state. Closely related problem is the clarification of the notion of quantum randomness and its interrelation with classical randomness. In this short review, we shall discuss basics of classical theory of randomness (which by itself is very complex and characterized by diversity of approaches) and compare it with irreducible quantum randomness. We also discuss briefly “digital philosophy”, its role in physics (classical and quantum) and its coupling to the information interpretation of quantum mechanics (QM).

  17. Scalability of a Low-Cost Multi-Teraflop Linux Cluster for High-End Classical Atomistic and Quantum Mechanical Simulations

    NASA Technical Reports Server (NTRS)

    Kikuchi, Hideaki; Kalia, Rajiv K.; Nakano, Aiichiro; Vashishta, Priya; Shimojo, Fuyuki; Saini, Subhash

    2003-01-01

    Scalability of a low-cost, Intel Xeon-based, multi-Teraflop Linux cluster is tested for two high-end scientific applications: Classical atomistic simulation based on the molecular dynamics method and quantum mechanical calculation based on the density functional theory. These scalable parallel applications use space-time multiresolution algorithms and feature computational-space decomposition, wavelet-based adaptive load balancing, and spacefilling-curve-based data compression for scalable I/O. Comparative performance tests are performed on a 1,024-processor Linux cluster and a conventional higher-end parallel supercomputer, 1,184-processor IBM SP4. The results show that the performance of the Linux cluster is comparable to that of the SP4. We also study various effects, such as the sharing of memory and L2 cache among processors, on the performance.

  18. Density-Functional Theory with Dispersion-Correcting Potentials for Methane: Bridging the Efficiency and Accuracy Gap between High-Level Wave Function and Classical Molecular Mechanics Methods.

    PubMed

    Torres, Edmanuel; DiLabio, Gino A

    2013-08-13

    Large clusters of noncovalently bonded molecules can only be efficiently modeled by classical mechanics simulations. One prominent challenge associated with this approach is obtaining force-field parameters that accurately describe noncovalent interactions. High-level correlated wave function methods, such as CCSD(T), are capable of correctly predicting noncovalent interactions, and are widely used to produce reference data. However, high-level correlated methods are generally too computationally costly to generate the critical reference data required for good force-field parameter development. In this work we present an approach to generate Lennard-Jones force-field parameters to accurately account for noncovalent interactions. We propose the use of a computational step that is intermediate to CCSD(T) and classical molecular mechanics, that can bridge the accuracy and computational efficiency gap between them, and demonstrate the efficacy of our approach with methane clusters. On the basis of CCSD(T)-level binding energy data for a small set of methane clusters, we develop methane-specific, atom-centered, dispersion-correcting potentials (DCPs) for use with the PBE0 density-functional and 6-31+G(d,p) basis sets. We then use the PBE0-DCP approach to compute a detailed map of the interaction forces associated with the removal of a single methane molecule from a cluster of eight methane molecules and use this map to optimize the Lennard-Jones parameters for methane. The quality of the binding energies obtained by the Lennard-Jones parameters we obtained is assessed on a set of methane clusters containing from 2 to 40 molecules. Our Lennard-Jones parameters, used in combination with the intramolecular parameters of the CHARMM force field, are found to closely reproduce the results of our dispersion-corrected density-functional calculations. The approach outlined can be used to develop Lennard-Jones parameters for any kind of molecular system.

  19. Cardiopulmonary Manifestations of Ankylosing Spondylitis

    PubMed Central

    Momeni, Mahnaz; Taylor, Nora; Tehrani, Mahsa

    2011-01-01

    Ankylosing spondylitis is a chronic inflammatory condition that usually affects young men. Cardiac dysfunction and pulmonary disease are well-known and commonly reported extra-articular manifestation, associated with ankylosing spondylitis (AS). AS has also been reported to be specifically associated with aortitis, aortic valve diseases, conduction disturbances, cardiomyopathy and ischemic heart disease. The pulmonary manifestations of the disease include fibrosis of the upper lobes, interstitial lung disease, ventilatory impairment due to chest wall restriction, sleep apnea, and spontaneous pneumothorax. They are many reports detailing pathophysiology, hypothesized mechanisms leading to these derangements, and estimated prevalence of such findings in the AS populations. At this time, there are no clear guidelines regarding a stepwise approach to screen these patients for cardiovascular and pulmonary complications. PMID:21547038

  20. Heterolysis of H2 Across a Classical Lewis Pair, 2,6-Lutidine-BCl3: Synthesis, Characterization, and Mechanism

    SciTech Connect

    Ginovska-Pangovska, Bojana; Autrey, Thomas; Parab, Kshitij K.; Bowden, Mark E.; Potter, Robert G.; Camaioni, Donald M.

    2015-09-10

    We report on a combined computational and experimental study of the activation of hydrogen using for 2,6-lutidine (Lut)/BCl3 Lewis pairs. Herein we describe the synthetic approach used to obtain a new FLP, Lut-BCl3 that activates molecular H2 at ~10 bar, 100 °C in toluene or lutidine as the solvent. The resulting compound is an unexpected neutral hydride, LutBHCl2, rather than the ion pair, which we attribute to ligand redistribution. The mechanism for activation was modeled with density functional theory and accurate G3(MP2)B3 theory. The dative bond in Lut-BCl3 is calculated to have a bond enthalpy of 15 kcal/mol. The separated pair is calculated to react with H2 and form the [LutH+][HBCl3–] ion pair with a barrier of 13 kcal/mol. Metathesis with LutBCl3 produces LutBHCl2 and [LutH][BCl4]. The overall reaction is exothermic by 8.5 kcal/mol. An alternative pathway was explored involving lutidine–borenium cation pair activating H2. This work was supported by the U.S. Department of Energy's (DOE) Office of Basic Energy Sciences, Division of Chemical Sciences, Biosciences, and Geosciences, and was performed in part using the Molecular Science Computing Facility (MSCF) in the William R. Wiley Environmental Molecular Sciences Laboratory, a DOE national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at the Pacific Northwest National Laboratory (PNNL). PNNL is operated by Battelle for DOE.

  1. Reexamining the Quantum-Classical Relation

    NASA Astrophysics Data System (ADS)

    Bokulich, Alisa

    2008-10-01

    1. Intertheoretic relations: are imperialism and isolationism our only options?; 2. Heisenberg's closed theories and pluralistic realism; 3. Dirac's open theories and the reciprocal correspondence principle; 4. Bohr's generalization of classical mechanics; 5. Semiclassical mechanics: putting quantum flesh on classical bones; 6. Can classical structures explain quantum phenomena?; 7. A structural approach to intertheoretic relations; References; Index.

  2. [Unusual Migraine Manifestations].

    PubMed

    Schipper, Sivan; Gantenbein, Andreas R; Sandor, Peter S

    2016-06-08

    Migraine is a complex neurologic disorder by which several systems of the central nervous system (autonomous system, affective, cognitive, sensoric and motoric system) may be affected on different levels. Around a fourth of the patients have migraine aura. The most common aura is the visual aura, followed by sensoric aura. But motoric deficits as well as deficits of higher cortical centers (disorders of thinking, orientation, coherence or concentration) may occur as well. In analogy with a headache calendar, an aura calendar can deliver important help in the diagnostic process of rare migraine manifestations and prevent underdiagnosis of unusual migraine manifestations. Complex migraine manifestations are diagnoses of exlusion, and a broad diagnostic work-up is warranted in order to exclude dangerous neurologic pathologies. There are no specific therapeutic recommendations, as there is a lack of randomized controlled studies.

  3. Manifestations of Lyme carditis.

    PubMed

    Kostić, Tomislav; Momčilović, Stefan; Perišić, Zoran D; Apostolović, Svetlana R; Cvetković, Jovana; Jovanović, Andriana; Barać, Aleksandra; Šalinger-Martinović, Sonja; Tasić-Otašević, Suzana

    2017-04-01

    The first data of Lyme carditis, a relatively rare manifestation of Lyme disease, were published in eighties of the last century. Clinical manifestations include syncope, light-headedness, fainting, shortness of breath, palpitations, and/or chest pain. Atrioventricular (AV) electrical block of varying severity presents the most common conduction disorder in Lyme carditis. Although is usually mild, AV block can fluctuates rapidly and progress from a prolonged P-R interval to a His-Purkinje block within minutes to hours and days. Rarely, Lyme disease may be the cause of endocarditis, while some studies and reports, based on serological and/or molecular investigations, have suggested possible influence of Borrelia burgdorferi on degenerative cardiac valvular disease. Myocarditis, pericarditis, pancarditis, dilated cardiomyopathy, and heart failure have also been described as possible manifestations of Lyme carditis. The clinical course of Lyme carditis is generally mild, short term, and in most cases, completely reversible after adequate antibiotic treatment.

  4. Cutaneous Manifestations of ESRD

    PubMed Central

    Cronin, Antonia J.; Leslie, Kieron S.

    2014-01-01

    Summary A broad range of skin diseases occurs in patients with ESRD: from the benign and asymptomatic to the physically disabling and life-threatening. Many of them negatively impact on quality of life. Their early recognition and treatment are essential in reducing morbidity and mortality. The cutaneous manifestations can be divided into two main categories: nonspecific and specific. The nonspecific manifestations are commonly seen and include skin color changes, xerosis, half-and-half nails, and pruritus. The specific disorders include acquired perforating dermatosis, bullous dermatoses, metastatic calcification, and nephrogenic systemic fibrosis. This review article describes these conditions and considers the underlying pathophysiology, clinical presentations, diagnosis, and treatment options. PMID:24115194

  5. [Pulmonary manifestations of antisynthetase syndrome].

    PubMed

    Jouneau, S; Hervier, B; Jutant, E-M; Decaux, O; Kambouchner, M; Humbert, M; Delaval, P; Montani, D

    2015-06-01

    Antisynthetase syndrome is an inflammatory myopathy frequently associated with pulmonary manifestations, especially interstitial lung diseases, and uncommonly pulmonary hypertension. In the context of a suggestive clinical and radiological picture, positive anti-RNA synthetase antibodies confirm the diagnosis. Anti-Jo1, anti-PL7, and anti-PL12 antibodies are the more commonly encountered. The presence of a number of extra-thoracic manifestations in association with pulmonary disease may suggest the diagnosis. These include: myalgia or muscular deficit, Raynaud's phenomenon, polyarthritis, fever, mechanics hands. Serum creatine kinase levels are usually increased. Electromyogram, muscular magnetic resonance imaging or muscle pathology are not mandatory to make the diagnosis. There is a high variability in symptoms and severity, between patients but also during the course of the disease in the same patient. The presence of an interstitial lung disease is a major prognostic factor and an indication for more intensive treatment, principally with systemic corticosteroids with or without immunosuppressive drugs. Improving respiratory physicians' knowledge of this disease, which is often revealed by its pulmonary manifestations, should help diagnosis, therapeutic management, and possibly prognosis.

  6. Destiny - Not So Manifest.

    ERIC Educational Resources Information Center

    Kerr, Clark

    Higher education in the United States is facing a period of uncertainty, confusion, conflict, and potential change, and it has little to guide it in its past experiences. For most of its three and one-third century history, it has had a manifest destiny and through the period from 1820-1870 was marked by rapid change and some student unrest. Two…

  7. Hazardous Waste Manifest System

    EPA Pesticide Factsheets

    EPA’s hazardous waste manifest system is designed to track hazardous waste from the time it leaves the generator facility where it was produced, until it reaches the off-site waste management facility that will store, treat, or dispose of the waste.

  8. Extra-articular Manifestations in Rheumatoid Arthritis

    PubMed Central

    Cojocaru, Manole; Cojocaru, Inimioara Mihaela; Silosi, Isabela; Vrabie, Camelia Doina; Tanasescu, R

    2010-01-01

    ABSTRACT Rheumatoid arthritis (RA) is a systemic autoimmune disease whose main characteristic is persistent joint inflammation that results in joint damage and loss of function. Although RA is more common in females, extra-articular manifestations of the disease are more common in males. The extra-articular manifestations of RA can occur at any age after onset. It is characterised by destructive polyarthritis and extra-articular organ involvement, including the skin, eye, heart, lung, renal, nervous and gastrointestinal systems. The frequence of extra-articular manifestations in RA differs from one country to another. Extra-articular organ involvement in RA is more frequently seen in patients with severe, active disease and is associated with increased mortality. Incidence and frequence figures for extra-articular RA vary according to study design. Extra-articular involvement is more likely in those who have RF and/or are HLA-DR4 positive. Occasionally, there are also systemic manifestations such as vasculitis, visceral nodules, Sjögren's syndrome, or pulmonary fibrosis present. Nodules are the most common extra-articular feature, and are present in up to 30%; many of the other classic features occur in 1% or less in normal clinic settings. Sjögren's syndrome, anaemia of chronic disease and pulmonary manifestations are relatively common – in 6-10%, are frequently present in early disease and are all related to worse outcomes measures of rheumatoid disease in particular functional impairment and mortality. The occurrence of these systemic manifestations is a major predictor of mortality in patients with RA. This paper focuses on extra-articular manifestations, defined as diseases and symptoms not directly related to the locomotor system. PMID:21977172

  9. Classical and quantum routes to linear magnetoresistance

    NASA Astrophysics Data System (ADS)

    Hu, Jingshi

    The transverse, positive magnetoresistance of suitably doped silver chalcogenides and indium antimonides changes linearly with magnetic field by thousands of percent, with no sign of saturation up to MegaGauss. A precise characterization of these unexpected observations has led to two very different, yet equally interesting magnetotransport mechanisms: the classical inhomogeneity-induced current jetting, and quantum linear magnetoresistance. The inhomogeneous distribution of excess/deficient silver atoms lies behind the anomalous magnetoresistive response of silver chalcogenides, introducing spatial conductivity fluctuations with length scales independent of the cyclotron radius. We show that a systematic investigation of the resistivity tensor in longitudinal field could be used to identify the spatial inhomogeneities and determine the associated length scale of the current distortion. By contrast, the linear magnetoresistance observed in single-crystalline InSb presents a spectacular manifestation of magnetotransport in the extreme quantum limit, when only one Landau band is partially filled. Harnessing both the classical and quantum effects opens the gate to artificial fabrication of conducting networks with micron scale unit size for enhanced magnetoresistive sensitivity.

  10. What classicality? Decoherence and Bohr's classical concepts

    NASA Astrophysics Data System (ADS)

    Schlosshauer, Maximilian; Camilleri, Kristian

    2011-03-01

    Niels Bohr famously insisted on the indispensability of what he termed "classical concepts." In the context of the decoherence program, on the other hand, it has become fashionable to talk about the "dynamical emergence of classicality" from the quantum formalism alone. Does this mean that decoherence challenges Bohr's dictum—for example, that classical concepts do not need to be assumed but can be derived? In this paper we'll try to shed some light down the murky waters where formalism and philosophy cohabitate. To begin, we'll clarify the notion of classicality in the decoherence description. We'll then discuss Bohr's and Heisenberg's take on the quantum—classical problem and reflect on different meanings of the terms "classicality" and "classical concepts" in the writings of Bohr and his followers. This analysis will allow us to put forward some tentative suggestions for how we may better understand the relation between decoherence-induced classicality and Bohr's classical concepts.

  11. Non-classical mechanisms of transcriptional regulation by the vitamin D receptor: insights into calcium homeostasis, immune system regulation and cancer chemoprevention.

    PubMed

    Dimitrov, Vassil; Salehi-Tabar, Reyhaneh; An, Beum-Soo; White, John H

    2014-10-01

    Hormonal 1,25-dihydroxyvitamin D [1,25(OH)2D] signals through the nuclear vitamin D receptor (VDR), a ligand-regulated transcription factor. Gene expression profiling studies have revealed that 1,25(OH)2D signaling through the VDR can lead to activation or repression of target gene transcription in roughly equal proportions. Classically, transcriptional regulation by the VDR, similar to other nuclear receptors, has been characterized by its capacity to recognize high affinity cognate vitamin D response elements (VDREs), located in the regulatory regions of target genes. Several biochemical studies revealed that the VDRE-bound receptor recruits a series of coregulatory proteins, leading to transactivation of adjacent target genes. However, genome-wide and other analyses of VDR binding have revealed that a subset of VDR binding sites does not contain VDREs, and that VDREs are not associated with transcriptionally repressed VDR target genes. Work over the last ∼20 years and in particular recent findings have revealed a diverse array of mechanisms by which VDR can form complexes with several other classes of transcriptional activators, leading to repression of gene transcription. Moreover, these efforts have led to several insights into the molecular basis for the physiological regulation of calcium homeostasis, immune system function and cancer chemoprevention by 1,25(OH)2D/VDR signaling. This article is part of a Special Issue entitled '16th Vitamin D Workshop'.

  12. The coupling between stability and ion pair formation in magnesium electrolytes from first-principles quantum mechanics and classical molecular dynamics.

    PubMed

    Rajput, Nav Nidhi; Qu, Xiaohui; Sa, Niya; Burrell, Anthony K; Persson, Kristin A

    2015-03-11

    In this work we uncover a novel effect between concentration dependent ion pair formation and anion stability at reducing potentials, e.g., at the metal anode. Through comprehensive calculations using both first-principles as well as well-benchmarked classical molecular dynamics over a matrix of electrolytes, covering solvents and salt anions with a broad range in chemistry, we elucidate systematic correlations between molecular level interactions and composite electrolyte properties, such as electrochemical stability, solvation structure, and dynamics. We find that Mg electrolytes are highly prone to ion pair formation, even at modest concentrations, for a wide range of solvents with different dielectric constants, which have implications for dynamics as well as charge transfer. Specifically, we observe that, at Mg metal potentials, the ion pair undergoes partial reduction at the Mg cation center (Mg(2+) → Mg(+)), which competes with the charge transfer mechanism and can activate the anion to render it susceptible to decomposition. Specifically, TFSI(-) exhibits a significant bond weakening while paired with the transient, partially reduced Mg(+). In contrast, BH4(-) and BF4(-) are shown to be chemically stable in a reduced ion pair configuration. Furthermore, we observe that higher order glymes as well as DMSO improve the solubility of Mg salts, but only the longer glyme chains reduce the dynamics of the ions in solution. This information provides critical design metrics for future electrolytes as it elucidates a close connection between bulk solvation and cathodic stability as well as the dynamics of the salt.

  13. Oral manifestations of hyperoxaluria.

    PubMed

    Guerra, Eliete Neves da Silva; Vianna, Leonora; Sobreira, Maria Nazareth; de Araújo, Flavio Nader Gross; de Melo, Nilce Santos

    2011-11-01

    Primary hyperoxaluria is a rare, inherited autosomal recessive disease caused by defects in the metabolism of glyoxylate. Oral manifestations of hyperoxaluria are rare. However, bone and tooth resorption may be the result of chronic inflammation and the presence of osteoclastic cells surrounding the oxalate crystal deposit. A deposit of calcium oxalate in the periodontium was identified in a patient with end-stage renal disease. Dental radiographs indicated bone loss and external tooth resorption. Radiolucent image in the inferior incisor region was observed and removed. The tissue showed granulomatous inflammation with foreign body reaction and associated crystalline deposits. When viewed in polarized light, these deposits are green and presented a birefringent aspect, which were interpreted as calcium oxalate crystals compatible with oxaluria. Oral manifestations of hyperoxaluria are of particular interest because of the unusual location of the oxalate crystal deposition, resulting in aggressive tooth resorption and alveolar bone loss, which may be misdiagnosed.

  14. Inflammatory Manifestations of Lymphedema

    PubMed Central

    Ly, Catherine L.; Kataru, Raghu P.; Mehrara, Babak J.

    2017-01-01

    Lymphedema results from lymphatic insufficiency leading to a progressive inflammatory process that ultimately manifests as discomfort, recurrent infections, and, at times, secondary malignancy. Collectively, these morbidities contribute to an overall poor quality of life. Although there have been recent advances in microsurgical interventions, a conservative palliative approach remains the mainstay of treatment for this disabling disease. The absence of a cure is due to an incomplete understanding of the pathophysiological changes that result in lymphedema. A histological hallmark of lymphedema is inflammatory cell infiltration and recent studies with animal models and clinical biopsy specimens have suggested that this response plays a key role in the pathology of the disease. The purpose of this report is to provide an overview of the ongoing research in and the current understanding of the inflammatory manifestations of lymphedema. PMID:28106728

  15. Diverse manifestations of trichloroethylene.

    PubMed Central

    McCunney, R J

    1988-01-01

    Trichloroethylene, a solvent used in a variety of industrial settings for more than 60 years, has caused adverse health effects on the central and peripheral nervous system, the skin, liver, kidney, and heart. Three men have shown relatively unusual manifestations secondary to exposure to trichloroethylene in degreasing operations in the jewelry industry. Toxic encephalopathy, hepatitis, and carpal spasm occurred among young, healthy workers. Clinical and laboratory data, including measurement of urinary trichloroacetic acid concentrations, are presented. PMID:3342194

  16. [Respiratory manifestations in aspergillosis].

    PubMed

    Regimbaud, M

    1986-01-01

    Aspergillus is a genus of cosmopolitan fungi with a selective pulmonary tropism. Their pathogenic role is due either to spreading in pre-existing pulmonary cavities, or to their allergizing capacity. Cavitary sequellae of tuberculosis and suppuration, particularly frequent and important in tropical environment, are elective localization for Aspergillus colonization. Surgical treatment is nowadays the only efficient one. Allergic manifestations are a more complex problem of therapy, exclusion of allergen being difficult to get in tropical environment.

  17. Current concepts in organic acidurias: understanding intra- and extracerebral disease manifestation.

    PubMed

    Kölker, Stefan; Burgard, Peter; Sauer, Sven W; Okun, Jürgen G

    2013-07-01

    This review focuses on the pathophysiology of organic acidurias (OADs), in particular, OADs caused by deficient amino acid metabolism. OADs are termed classical if patients present with acute metabolic decompensation and multiorgan dysfunction or cerebral if patients predominantly present with neurological symptoms but without metabolic crises. In both groups, however, the brain is the major target. The high energy demand of the brain, the gate-keeping function of the blood-brain barrier, a high lipid content, vulnerable neuronal subpopulations, and glutamatergic neurotransmission all make the brain particularly vulnerable against mitochondrial dysfunction, oxidative stress, and excitotoxicity. In fact, toxic metabolites in OADs are thought to cause secondary impairment of energy metabolism; some of these toxic metabolites are trapped in the brain. In contrast to cerebral OADs, patients with classical OADs have an increased risk of multiorgan dysfunction. The lack of the anaplerotic propionate pathway, synergistic inhibition of energy metabolism by toxic metabolites, and multiple oxidative phosphorylation (OXPHOS) deficiency may best explain the involvement of organs with a high energy demand. Intriguingly, late-onset organ dysfunction may manifest even under metabolically stable conditions. This might be explained by chronic mitochondrial DNA depletion, increased production of reactive oxygen species, and altered gene expression due to histone modification. In conclusion, pathomechanisms underlying the acute disease manifestation in OADs, with a particular focus on the brain, are partially understood. More work is required to predict the risk and to elucidate the mechanism of late-onset organ dysfunction, extracerebral disease manifestation, and tumorigenesis.

  18. Hazardous Waste Electronic Manifest System (E-Manifest)

    EPA Pesticide Factsheets

    This webpage provides information on EPA's work toward developing a hazardous waste electronic manifest system. Information on the Hazardous Waste Electronic Manifest Establishment Act, progress on the project and frequent questions are available.

  19. Entanglement with classical fields

    SciTech Connect

    Lee, K.F.; Thomas, J.E.

    2004-05-01

    We experimentally demonstrate a simple classical-field optical heterodyne method which employs postselection to reproduce the polarization correlations of a four-particle entangled state. We give a heuristic argument relating this method to the measurement of multiple quantum fields by correlated homodyne detection. We suggest that using multiple classical fields and postselection, one can reproduce the polarization correlations obtained in quantum experiments which employ multiple single-photon sources and linear optics to prepare multiparticle entangled states. Our experimental scheme produces four spatially separated beams which are separately detected by mixing with four independent optical local oscillators (LO) of variable polarization. Analog multiplication of the four beat signals enables projection onto a four-particle polarization-state basis. Appropriate band pass filtering is used to produce a signal proportional to the projections of the maximally entangled four-field polarization state, H{sub 1})H{sub 2})H{sub 3})H{sub 4})+V{sub 1})V{sub 2})V{sub 3})V{sub 4}), onto the product of the four LO polarizations. Since the data from multiple observers is combined prior to postselection, this method does not constitute a test of nonlocality. However, we reproduce the polarization correlations of the 32 elements in the truth table from the quantum mechanical Greenberger-Horne-Zeilinger experiments on the violation of local realism. We also demonstrate a form of classical entanglement swapping in a four-particle basis.

  20. The coupling between stability and ion pair formation in magnesium electrolytes from first-principles quantum mechanics and classical molecular dynamics

    DOE PAGES

    Rajput, Nav Nidhi; Qu, Xiaohuui; Sa, Niya; ...

    2015-02-10

    Here in this work we uncover a novel effect between concentration dependent ion pair formation and anion stability at reducing potentials, e.g., at the metal anode. Through comprehensive calculations using both first-principles as well as well-benchmarked classical molecular dynamics over a matrix of electrolytes, covering solvents and salt anions with a broad range in chemistry, we elucidate systematic correlations between molecular level interactions and composite electrolyte properties, such as electrochemical stability, solvation structure, and dynamics. We find that Mg electrolytes are highly prone to ion pair formation, even at modest concentrations, for a wide range of solvents with different dielectricmore » constants, which have implications for dynamics as well as charge transfer. Specifically, we observe that, at Mg metal potentials, the ion pair undergoes partial reduction at the Mg cation center (Mg2+ -> Mg+), which competes with the charge transfer mechanism and can activate the anion to render it susceptible to decomposition. Specifically, TFSI exhibits a significant bond weakening while paired with the transient, partially reduced Mg+. In contrast, BH4$-$ and BF4$-$ are shown to be chemically stable in a reduced ion pair configuration. Furthermore, we observe that higher order glymes as well as DMSO improve the solubility of Mg salts, but only the longer glyme chains reduce the dynamics of the ions in solution. This information provides critical design metrics for future electrolytes as it elucidates a close connection between bulk solvation and cathodic stability as well as the dynamics of the salt.« less

  1. The coupling between stability and ion pair formation in magnesium electrolytes from first-principles quantum mechanics and classical molecular dynamics

    SciTech Connect

    Rajput, Nav Nidhi; Qu, Xiaohuui; Sa, Niya; Burrell, Anthony K.; Persson, Kristin A.

    2015-02-10

    Here in this work we uncover a novel effect between concentration dependent ion pair formation and anion stability at reducing potentials, e.g., at the metal anode. Through comprehensive calculations using both first-principles as well as well-benchmarked classical molecular dynamics over a matrix of electrolytes, covering solvents and salt anions with a broad range in chemistry, we elucidate systematic correlations between molecular level interactions and composite electrolyte properties, such as electrochemical stability, solvation structure, and dynamics. We find that Mg electrolytes are highly prone to ion pair formation, even at modest concentrations, for a wide range of solvents with different dielectric constants, which have implications for dynamics as well as charge transfer. Specifically, we observe that, at Mg metal potentials, the ion pair undergoes partial reduction at the Mg cation center (Mg2+ -> Mg+), which competes with the charge transfer mechanism and can activate the anion to render it susceptible to decomposition. Specifically, TFSI exhibits a significant bond weakening while paired with the transient, partially reduced Mg+. In contrast, BH4$-$ and BF4$-$ are shown to be chemically stable in a reduced ion pair configuration. Furthermore, we observe that higher order glymes as well as DMSO improve the solubility of Mg salts, but only the longer glyme chains reduce the dynamics of the ions in solution. This information provides critical design metrics for future electrolytes as it elucidates a close connection between bulk solvation and cathodic stability as well as the dynamics of the salt.

  2. Testing the Palma-Clary Reduced Dimensionality Model Using Classical Mechanics on the CH4 + H → CH3 + H2 Reaction.

    PubMed

    Vikár, Anna; Nagy, Tibor; Lendvay, György

    2016-07-14

    Application of exact quantum scattering methods in theoretical reaction dynamics of bimolecular reactions is limited by the complexity of the equations of nuclear motion to be solved. Simplification is often achieved by reducing the number of degrees of freedom to be explicitly handled by freezing the less important spectator modes. The reaction cross sections obtained in reduced-dimensionality (RD) quantum scattering methods can be used in the calculation of rate coefficients, but their physical meaning is limited. The accurate test of the performance of a reduced-dimensionality method would be a comparison of the RD cross sections with those obtained in accurate full-dimensional (FD) calculations, which is not feasible because of the lack of complete full-dimensional results. However, classical mechanics allows one to perform reaction dynamics calculations using both the RD and the FD model. In this paper, an RD versus FD comparison is made for the 8-dimensional Palma-Clary model on the example of four isotopologs of the CH4 + H → CH3 + H2 reaction, which has 12 internal dimensions. In the Palma-Clary model, the only restriction is that the methyl group is confined to maintain C3v symmetry. Both RD and FD opacity and excitation functions as well as differential cross sections were calculated using the quasiclassical trajectory method. The initial reactant separation has been handled according to our one-period averaging method [ Nagy et al. J. Chem. Phys. 2016, 144, 014104 ]. The RD and FD excitation functions were found to be close to each other for some isotopologs, but in general, the RD reactivity parameters are lower than the FD reactivity parameters beyond statistical error, and for one of the isotopologs, the deviation is significant. This indicates that the goodness of RD cross sections cannot be taken for granted.

  3. Ophthalmologic manifestations of celiac disease

    PubMed Central

    Martins, Thiago Gonçalves dos Santos; Costa, Ana Luiza Fontes de Azevedo; Oyamada, Maria Kiyoko; Schor, Paulo; Sipahi, Aytan Miranda

    2016-01-01

    Celiac disease is an autoimmune disorder that affects the small intestine of genetically predisposed individuals. Ophthalmic manifestations are within the extra-intestinal manifestations, and can be divided into those of autoimmune disorders or those due to absorptive disabilities. This article reviewed the ophthalmologic manifestation of celiac disease. Ophthalmic symptoms are rare, but should be investigated in patients with celiac disease and taken into consideration as the first systemic manifestation. PMID:26949627

  4. [Ocular Manifestations in Sarcoidosis].

    PubMed

    Walscheid, K; Tappeiner, C; Heiligenhaus, A

    2016-05-01

    Sarcoidosis is an inflammatory multi-organ disease of unknown pathogenesis, characterised by non-necrotising granulomata. Sarcoidosis predominantly manifests in the lung, but any other organ may be affected. Ocular involvement is present in about 25 to 50 % of patients. The most common ocular manifestation is uveitis, especially of the anterior eye segment. If ocular sarcoidosis is suspected, interdisciplinary assessment of the patient is mandatory, including laboratory tests, chest X-ray, assessment by a specialist in internal medicine and, ideally, histological evidence of granuloma formation in a tissue specimen. Other (infectious) causes of granulomatous inflammation need to be excluded, especially tuberculosis or syphilis. For the ophthalmological assessment, detection of granulomatous lesions is of particular importance, especially by visualising chorioretinal granuloma by fluorescein and indocyanin green angiography. Cystoid macular oedema and glaucoma are the most frequent complications limiting visual acuity. Corticosteroids, which can be administered either locally or systemically, are the mainstay of therapy. Depending on the clinical course and the development of ocular complications, systemic steroid-sparing immunosuppressive medication may be indicated.

  5. [Protracted rheumatologic manifestations in travelers].

    PubMed

    Levy, Tali; Kivity, Shaye; Schwartz, Eli

    2010-09-01

    Protracted rheumatological manifestations especially arthralgia and or polyarthritis may occur as a consequence of a wide range of pathogens including viral, bacterial and parasites. Few pathogenetic mechanisms leading to these clinical presentations have been suggested including a direct invasion of the synovial cells by the pathogens, immune complex formation, and others. The natural history of infectious arthritis/arthralgia is altogether benign, with full recovery and without sequelae, albeit sometimes very long. Diagnosis of infections-related arthralgia/arthritis is important since these diseases have a better prognosis, and can relieve anxiety among patients who are afraid of developing a chronic rheumatic disease. Since many patients will seek medical advice with these chronic complaints a long time after travel, physicians should be aware of the possible association between these complaints and remote travel. Thus, travel history should be mandatory, even in a rheumatologic setting.

  6. Psoriasis: pathophysiology and oral manifestations.

    PubMed

    Zhu, J F; Kaminski, M J; Pulitzer, D R; Hu, J; Thomas, H F

    1996-06-01

    Psoriasis is a chronic, remitting and relapsing inflammatory skin disorder with a strong genetic predisposition. Psoriasis affects 1-3% of the world's population in their early lives representing a disabling condition with significant social and economic impact. Despite a great deal of research on the etiology and tissue destruction mechanisms, the disease is not well understood. The purpose of this paper is to provide current information from the literature with a special focus on oral manifestations. The major signs and symptoms presented in the oral environment of a psoriasis patient may include geographic tongue, fissure tongue, gingival and/or mucosal lesions. Inflammatory temporomandibular joint lesions have been reported in less than 5% of psoriasis patients. Multiple treatment strategies, be they topical or systemic, have been applied to these patients for symptom relief but not for cure.

  7. New developments in classical chaotic scattering.

    PubMed

    Seoane, Jesús M; Sanjuán, Miguel A F

    2013-01-01

    Classical chaotic scattering is a topic of fundamental interest in nonlinear physics due to the numerous existing applications in fields such as celestial mechanics, atomic and nuclear physics and fluid mechanics, among others. Many new advances in chaotic scattering have been achieved in the last few decades. This work provides a current overview of the field, where our attention has been mainly focused on the most important contributions related to the theoretical framework of chaotic scattering, the fractal dimension, the basins boundaries and new applications, among others. Numerical techniques and algorithms, as well as analytical tools used for its analysis, are also included. We also show some of the experimental setups that have been implemented to study diverse manifestations of chaotic scattering. Furthermore, new theoretical aspects such as the study of this phenomenon in time-dependent systems, different transitions and bifurcations to chaotic scattering and a classification of boundaries in different types according to symbolic dynamics are also shown. Finally, some recent progress on chaotic scattering in higher dimensions is also described.

  8. Genitourinary manifestations of tuberculosis.

    PubMed

    Wise, Gilbert J; Marella, Venkata K

    2003-02-01

    By the 1980s, the availability of antituberculosis chemotherapy reduced the incidence and prevalence of tuberculosis. Changing patterns of population emigration and the development of large pools of immune-compromised individuals reversed the downward trend of tuberculosis. The incidence of genitourinary tuberculosis has remained constant. The manifestations of GU TB can be variable and cause a variety of clinical patterns that mimic other diseases. Adrenal insufficiency, renal disease, obstructive uropathy, and chronic cystitis are not uncommon with TB. The patient with TB may have genital disease that simulates STD or scrotal tumors. Infertility can be caused by GU tuberculosis. Awareness of environmental factors and patient history should alert the urologist to the wide array of clinical findings in the genitourinary system that can be caused by tuberculosis.

  9. Ophthalmic manifestations postlightning strike

    PubMed Central

    Dhillon, Permesh Singh; Gupta, Mohit

    2015-01-01

    Various ophthalmic complications affecting the anterior and posterior segments have been identified due to lightning strike. We report the first case of an indirect lightning-induced full thickness macular hole formation in the UK as evidenced by slit lamp examination and optical coherence tomography (OCT) scan in a 77-year-old woman presenting with sudden visual loss in her right eye and thermal skin injury affecting her scalp. Her best corrected visual acuities were LogMAR 0.46 and 0.12 in the right and left eyes, respectively. There were no other ocular manifestations observed in either eye. She was initially managed conservatively with non-steroidal anti-inflammatory drug eye drops but surgery was later advised due to minimal changes in the visual acuity and macular hole on follow-up. OCT scanning is important in diagnosing macular holes, which usually warrant surgical intervention. PMID:25827914

  10. Manifold manifestations of ergotism.

    PubMed

    Payne, B; Sasse, B; Franzen, D; Hailemariam, S; Gemsenjäger, E

    2000-08-19

    Vasospastic side effects leading to organic manifestations are rare in ergotamine therapy. To our knowledge, combinations of more than two signs of ergotism have rarely been described in the literature so far. We present a 65-year-old male patient who as a consequence of severe migraine had developed ergotamine abuse. He was admitted to our hospital after one week of increasing abdominal pain. During laparotomy, necrotic areas of the small intestine and the sigmoid colon were resected, which on histopathologic examination revealed severe hypertrophy of the smooth musculature of mesenteric arteries, resulting from chronic vasospasms. Postoperatively, the patient developed ischaemia of the limbs which was confirmed by angiography. Before death, the patient also showed ischaemic signs in the acrae and necrosis of the tongue.

  11. Idiopathic Pulmonary Fibrosis: Diagnosis and Clinical Manifestations

    PubMed Central

    Nakamura, Yutaro; Suda, Takafumi

    2015-01-01

    Idiopathic pulmonary fibrosis (IPF) is a parenchymal lung disease characterized by progressive interstitial fibrosis. The clinical course of IPF can be unpredictable and may be punctuated by acute exacerbations. Although much progress is being made in unraveling the mechanisms underlying IPF, effective therapy for improving survival remains elusive. Longitudinal disease profiling, especially in terms of clinical manifestations in a large cohort of patients, should lead to proper management of the patients and development of new treatments for IPF. Appropriate multidisciplinary assessment in ongoing registries is required to achieve this. This review summarizes the current status of the diagnosis and clinical manifestations of IPF. PMID:27625576

  12. Classical anomalies for spinning particles

    NASA Astrophysics Data System (ADS)

    Gamboa, Jorge; Plyushchay, Mikhail

    1998-02-01

    We discuss the phenomenon of classical anomaly. It is observed for 3D Berezin-Marinov (BM), Barducci-Casalbuoni-Lusanna (BCL) and Cortés-Plyushchay-Velázquez (CPV) pseudoclassical spin particle models. We show that quantum mechanically these different models correspond to the same P, T-invariant system of planar fermions, but the quantum system has global symmetries being not reproducible classically in full in any of the models. We demonstrate that the specific U(1) gauge symmetry characterized by the opposite coupling constants of spin s = + {1}/{2} and s = - {1}/{2} states has a natural classical analog in the CPV model but can be reproduced in the BM and BCL models in an obscure and rather artificial form. We also show that the BM and BCL models quantum mechanically are equivalent in any odd-dimensional space-time, but describe different quantum systems in even space-time dimensions.

  13. Respiratory manifestations in endocrine diseases

    PubMed Central

    LENCU, CODRUŢA; ALEXESCU, TEODORA; PETRULEA, MIRELA; LENCU, MONICA

    2016-01-01

    The control mechanisms of respiration as a vital function are complex: voluntary – cortical, and involuntary – metabolic, neural, emotional and endocrine. Hormones and hypothalamic neuropeptides (that act as neurotrasmitters and neuromodulators in the central nervous system) play a role in the regulation of respiration and in bronchopulmonary morphology. This article presents respiratory manifestations in adult endocrine diseases that evolve with hormone deficit or hypersecretion. In hyperthyroidism, patients develop ventilation disorders, obstructive and central sleep apnea, and pleural collection. The respiratory abnormalities in hyperthyroidism as a result of the hypermetabolic action of thyroid hormones are hyperventilation, myopathy and cardiovascular involvement; recent studies have reported pulmonary arterial hypertension in Graves’ disease, as a result of the association of several mechanisms. Thyroid hypertrophy can induce through compression of the upper airways dyspnea, stridor, wheezing and cough. The respiratory disorders in acromegaly are ventilatory dysfunction and sleep apnea, which contribute to an unfavorable evolution of the disease. Respiratory changes in parathyroid, adrenal and reproductive system diseases have been described. Respiratory disorders should be recognized, investigated and monitored by medical practitioners of various specialties (family physicians, internists, endocrinologists, pneumologists, cardiologists). They are frequently severe, causing an unfavorable evolution of the associated endocrine and respiratory disease. PMID:27857512

  14. Cardiovascular manifestations of autonomic epilepsy.

    PubMed

    Freeman, Roy

    2006-02-01

    Cardiovascular autonomic manifestations of seizures occur frequently in the epileptic population. Common manifestations include alterations in heart rate and rhythm, blood pressure, ECG changes and chest pain. The neuroanatomical and neurophysiological underpinnings of these autonomic manifestations are not been fully elucidated. Diagnostic confusion may arise when ictal symptoms are confined to the autonomic nervous system; conversely, such symptoms in association with convulsions or altered consciousness are more readily recognized as concomitant ictal features. Awareness of the diverse autonomic manifestations of epilepsy will enhance diagnosis and lead to more effective therapy of these patients.

  15. Oral Manifestations of Vitiligo

    PubMed Central

    Nagarajan, Anitha; Masthan, Mahaboob Kader; Sankar, Leena Sankari; Narayanasamy, Aravindha Babu; Elumalai, Rajesh

    2015-01-01

    Background: Vitiligo is one of the disorder that has social impact. Both skin and mucous membrane show depigmentation in vitiligo. Depigmentation in oral cavity can be more easily observed and the patient can be given awareness regarding the condition if they are unaware of vitiligo elsewhere in their body and can be guided for treatment. Aim and objectives: The aim of this study is to determine the frequency of occurrence of oral mucosal vitiligo in vitiligo patients and to determine the most commonly involved oral mucosal site. Materials and methods: The study sample included 100 vitiligo patients. The patients of all age groups and both genders were included. Vitiligo patients associated with systemic conditions such as thyroid disorders, juvenile diabetes mellitus, pernicious anemia, Addison's disease were excluded in this study. Results: Out of 100 vitiligo patients 44 % male and 56% were female. The oral presentation of vitiligo in this study showed depigmentation of buccal mucosa in 5% of patients, labial mucosa in 5% of patients, palate in 8% of patients, gingiva in 2% of patients and alveolar mucosa 1%. Depigmentation of lip was seen in 42% of patients. Lip involvement refers to depigmentation of both the lips or either lip. Also vermilion border involvement was noted in majority of cases. In some cases, the depigmentation of lip extended to the facial skin also. Conclusion: In this study 55 patients out of 100 patients showed depigmentation in the oral cavity. Lip involvement was most common in this study showing about 42% of patients. Intraoral mucosal involvement was found in 21% of patients. Among intraoral mucosal site palate was common followed by buccal and labial mucosa, gingiva. Two patients had lip pigmentation as the only manifestation without any depigmentation in the skin. PMID:25657420

  16. Rheumatic manifestations of inflammatory bowel disease.

    PubMed

    Rodríguez-Reyna, Tatiana Sofía; Martínez-Reyes, Cynthia; Yamamoto-Furusho, Jesús Kazúo

    2009-11-28

    This article reviews the literature concerning rheumatic manifestations of inflammatory bowel disease (IBD), including common immune-mediated pathways, frequency, clinical course and therapy. Musculoskeletal complications are frequent and well-recognized manifestations in IBD, and affect up to 33% of patients with IBD. The strong link between the bowel and the osteo-articular system is suggested by many clinical and experimental observations, notably in HLA-B27 transgenic rats. The autoimmune pathogenic mechanisms shared by IBD and spondyloarthropathies include genetic susceptibility to abnormal antigen presentation, aberrant recognition of self, the presence of autoantibodies against specific antigens shared by the colon and other extra-colonic tissues, and increased intestinal permeability. The response against microorganisms may have an important role through molecular mimicry and other mechanisms. Rheumatic manifestations of IBD have been divided into peripheral arthritis, and axial involvement, including sacroiliitis, with or without spondylitis, similar to idiopathic ankylosing spondylitis. Other periarticular features can occur, including enthesopathy, tendonitis, clubbing, periostitis, and granulomatous lesions of joints and bones. Osteoporosis and osteomalacia secondary to IBD and iatrogenic complications can also occur. The management of the rheumatic manifestations of IBD consists of physical therapy in combination with local injection of corticosteroids and nonsteroidal anti-inflammatory drugs; caution is in order however, because of their possible harmful effects on intestinal integrity, permeability, and even on gut inflammation. Sulfasalazine, methotrexate, azathioprine, cyclosporine and leflunomide should be used for selected indications. In some cases, tumor necrosis factor-alpha blocking agents should be considered as first-line therapy.

  17. Insidious manifestation of pyogenic liver abscess caused by Streptococcus intermedius and Micrococcus luteus: a case report.

    PubMed

    Ioannou, Antreas; Xenophontos, Eleni; Karatsi, Alexandra; Petrides, Christos; Kleridou, Maro; Zintilis, Chrysostomos

    2016-01-01

    Pyogenic liver abscesses are caused by various microorganisms and usually present with fever, abdominal pain, leukocytosis and liver enzyme abnormalities. This case presents the insidious manifestation of a pyogenic liver abscess in a 34-year-old immunocompetent male, where classical manifestations of a liver abscess were absent. The microorganisms cultured from the abscess belonged to oral cavity's and gastrointestinal tract's normal flora.

  18. The Classical Vacuum.

    ERIC Educational Resources Information Center

    Boyer, Timothy H.

    1985-01-01

    The classical vacuum of physics is not empty, but contains a distinctive pattern of electromagnetic fields. Discovery of the vacuum, thermal spectrum, classical electron theory, zero-point spectrum, and effects of acceleration are discussed. Connection between thermal radiation and the classical vacuum reveals unexpected unity in the laws of…

  19. The Classics Revivified.

    ERIC Educational Resources Information Center

    Matthews, Dorothy, Ed.

    1979-01-01

    The eight articles in this bulletin suggest methods of introducing classical literature into the English curriculum. Article titles are: "Ideas for Teaching Classical Mythology"; "What Novels Should High School Students Read?"; "Enlivening the Classics for Live Students"; "Poetry in Performance: The Value of Song and Oral Interpretation in…

  20. Hyaline fibromatosis syndrome: cutaneous manifestations*

    PubMed Central

    Marques, Silvio Alencar; Stolf, Hamilton Ometto; Polizel, Juliana Ocanha; Munhoz, Tânia; Brandão, Marcela Calixto; Marques, Mariangela Esther Alencar

    2016-01-01

    Hyaline fibromatosis syndrome is the current name for clinical manifestations of diseases previously known as “infantile systemic hyalinosis” and “juvenile hyaline fibromatosis”. The authors report representative clinical cases of each one of the above subtypes with emphasis on cutaneous manifestations and difficulties for early diagnosis in this syndrome, essentially of multidisciplinary approach. PMID:27192526

  1. Classical three-box 'paradox'

    NASA Astrophysics Data System (ADS)

    Kirkpatrick, K. A.

    2003-05-01

    A simple classical probabilistic system (a simple card game) classically exemplifies Aharonov and Vaidman's 'three-box 'paradox'' (1991 J. Phys. A: Math. Gen. 24 2315), implying that the three-box example is neither quantal nor a paradox and leaving one with less difficulty to busy the interpreters of quantum mechanics. An ambiguity in the usual expression of the retrodiction formula is shown to have misled Albert et al (1985 Phys. Rev. Lett. 54 5) to a result not, in fact, 'curious'; the discussion illustrates how to avoid this ambiguity.

  2. Classical underpinnings of gravitationally induced quantum interference

    SciTech Connect

    Mannheim, P.D.

    1998-02-01

    We show that the gravitational modification of the phase of a neutron beam [the Colella-Overhauser-Werner (COW) experiment] has a classical origin, being due to the time delay that classical particles experience in traversing a background gravitational field. Similarly, we show that classical light waves also undergo a phase shift in traversing a gravitational field. We show that the COW experiment respects the equivalence principle even in the presence of quantum mechanics. {copyright} {ital 1998} {ital The American Physical Society}

  3. ELECTROMAGNETISM, OPTICS, ACOUSTICS, HEAT TRANSFER, CLASSICAL MECHANICS, AND FLUID DYNAMICS: Exact Soliton Solutions to a Generalized Nonlinear Schrödinger Equation

    NASA Astrophysics Data System (ADS)

    Xu, Si-Liu; Liang, Jian-Chu; Yi, Lin

    2010-01-01

    The (1+1)-dimensional F-expansion technique and the homogeneous nonlinear balance principle have been generalized and applied for solving exact solutions to a general (3+1)-dimensional nonlinear Schrödinger equation (NLSE) with varying coefficients and a harmonica potential. We found that there exist two kinds of soliton solutions. The evolution features of exact solutions have been numerically studied. The (3+1)D soliton solutions may help us to understand the nonlinear wave propagation in the nonlinear media such as classical optical waves and the matter waves of the Bose-Einstein condensates.

  4. GALK inhibitors for classic galactosemia.

    PubMed

    Lai, Kent; Boxer, Matthew B; Marabotti, Anna

    2014-06-01

    Classic galactosemia is an inherited metabolic disease for which, at present, no therapy is available apart from galactose-restricted diet. However, the efficacy of the diet is questionable, since it is not able to prevent the insurgence of chronic complications later in life. In addition, it is possible that dietary restriction itself could induce negative side effects. Therefore, there is a need for an alternative therapeutic approach that can avert the manifestation of chronic complications in the patients. In this review, the authors describe the development of a novel class of pharmaceutical agents that target the production of a toxic metabolite, galactose-1-phosphate, considered as the main culprit for the cause of the complications, in the patients.

  5. Skin manifestations of drug allergy

    PubMed Central

    Ardern-Jones, Michael R; Friedmann, Peter S

    2011-01-01

    Cutaneous adverse drug reactions range from mild to severe and from those localized only to skin to those associated with systemic disease. It is important to distinguish features of cutaneous drug reactions which help classify the underlying mechanism and likely prognosis as both of these influence management decisions, some of which necessarily have to be taken rapidly. Severe cutaneous reactions are generally T cell-mediated, yet this immunological process is frequently poorly understood and principles for identification of the culprit drug are different to those of IgE mediated allergic reactions. Furthermore, intervention in severe skin manifestations of drug allergy is frequently necessary. However, a substantial literature reports on success or otherwise of glucocorticoids, cyclophsphamide, ciclosporin, intravenous immunoglobulin and anti-tumour necrosis factor therapy for the treatment of toxic epidermal necrolysis without clear consensus. As well as reviewing the recommended supportive measures and evidence base for interventions, this review aims to provide a mechanistic overview relating to a proposed clinical classification to assist the assessment and management of these complex patients. PMID:21480947

  6. Entropy concepts in classical electrodynamics

    NASA Astrophysics Data System (ADS)

    Cole, Daniel C.

    2002-11-01

    Aspects of entropy and related thermodynamic analyses are discussed here that have been deduced in recent years in the area of classical electrodynamics. A motivating factor for most of this work has been an attempted theory of nature often called, "stochastic electrodynamics" (SED). This theory involves classical electrodynamics (Maxwell's equations plus the relativistic version of Newton's second law of motion for particles), but with the consideration that motion and fluctuations should not necessarily be assumed to reduce to zero at temperature T = 0. Both fairly subtle and rather blatant assumptions were often imposed in early thermodynamic analyses of electrodynamic systems that prevented the analyses from being sufficiently general to account for these "zero-point" properties, which hindered classical physics from being able to better account for quantum mechanical phenomena observed in nature. In turn, such thermodynamic considerations have helped motivate many of the key ideas of SED.

  7. Classical chaos and its correspondence in superconducting qubits

    NASA Astrophysics Data System (ADS)

    Neill, C.; Campbell, B.; Chen, Z.; Chiaro, B.; Dunsworth, A.; Fang, M.; Hoi, I.; Kelly, J.; Megrant, A.; O'Malley, P.; Quintana, C.; Vainsencher, A.; Wenner, J.; White, T.; Barends, R.; Chen, Yu; Fowler, A.; Jeffrey, E.; Mutus, J.; Roushan, P.; Sank, D.; Martinis, J. M.

    2015-03-01

    Advances in superconducting qubits have made it possible to experimentally investigate quantum-classical correspondence by constructing quantum systems with chaotic classical limits. We study the quantum equivalent of a classical spinning top using three fully coupled qubits that behave as a single spin-3/2 and subject the spin to a sequence of non-linear rotations. The resulting entanglement bears a striking resemblance to the classical phase space, including bifurcation, and suggests that classical chaos manifests itself as quantum entanglement. Studying the orientation of the spin-3/2 reveals that the rotations which generate chaos and entanglement are at the same time the source of disagreement between the quantum and classical trajectories. Our experiment highlights the correspondence between classical non-linear dynamics and interacting quantum systems.

  8. Chaos in the classical mechanics of bound and quasi-bound HX-4He complexes with X = F, Cl, Br, CN.

    PubMed

    Gamboa, Antonio; Hernández, Henar; Ramilowski, Jordan A; Losada, J C; Benito, R M; Borondo, F; Farrelly, David

    2009-10-01

    The classical dynamics of weakly bound floppy van der Waals complexes have been extensively studied in the past except for the weakest of all, i.e., those involving He atoms. These complexes are of considerable current interest in light of recent experimental work focussed on the study of molecules trapped in small droplets of the quantum solvent (4)He. Despite a number of quantum investigations, details on the dynamics of how quantum solvation occurs remain unclear. In this paper, the classical rotational dynamics of a series of van der Waals complexes, HX-(4)He with X = F, Cl, Br, CN, are studied. In all cases, the ground state dynamics are found to be almost entirely chaotic, in sharp contrast to other floppy complexes, such as HCl-Ar, for which chaos sets in only at relatively high energies. The consequences of this result for quantum solvation are discussed. We also investigate rotationally excited states with J = 1 which, except for HCN-(4)He, are actually resonances that decay by rotational pre-dissociation.

  9. Quantum–classical correspondence in chaotic dynamics of laser-driven atoms

    NASA Astrophysics Data System (ADS)

    Prants, S. V.

    2017-04-01

    This paper is a review article on some aspects of quantum–classical correspondence in chaotic dynamics of cold atoms interacting with a standing-wave laser field forming an optical lattice. The problem is treated from both (semi)classical and quantum points of view. In both approaches, the interaction of an atomic electic dipole with the laser field is treated quantum mechanically. Translational motion is described, at first, classically (atoms are considered to be point-like objects) and then quantum mechanically as a propagation of matter waves. Semiclassical equations of motion are shown to be chaotic in the sense of classical dynamical chaos. Point-like atoms in an absolutely deterministic and rigid optical lattice can move in a random-like manner demonstrating a chaotic walking with typical features of classical chaos. This behavior is explained by random-like ‘jumps’ of one of the atomic internal variable when atoms cross nodes of the standing wave and occurs in a specific range of the atom-field detuning. When treating atoms as matter waves, we show that they can make nonadiabatic transitions when crossing the standing-wave nodes. The point is that atomic wave packets split at each node in the same range of the atom-field detuning where the classical chaos occurs. The key point is that the squared amplitude of those semiclassical ‘jumps’ equal to the quantum Landau–Zener parameter which defines the probability of nonadiabatic transitions at the nodes. Nonadiabatic atomic wave packets are much more complicated compared to adiabatic ones and may be called chaotic in this sense. A few possible experiments to observe some manifestations of classical and quantum chaos with cold atoms in horizontal and vertical optical lattices are proposed and discussed.

  10. Quantum phase uncertainties in the classical limit

    NASA Technical Reports Server (NTRS)

    Franson, James D.

    1994-01-01

    Several sources of phase noise, including spontaneous emission noise and the loss of coherence due to which-path information, are examined in the classical limit of high field intensities. Although the origin of these effects may appear to be quantum-mechanical in nature, it is found that classical analogies for these effects exist in the form of chaos.

  11. Ocular manifestations of feline herpesvirus.

    PubMed

    Andrew, S E

    2001-03-01

    Feline herpesvirus-1 (FHV-1) infection is ubiquitous in the domestic cat population worldwide. The most common clinical ocular manifestations of infection with FHV-1 are conjunctivitis and keratitis. This paper reviews the pathogenesis of feline herpesvirus-1 and discusses the various clinical ocular manifestations, diagnostic techniques and treatment of FHV-1-induced diseases. Ocular manifestations include: conjunctivitis, keratitis, stromal keratitis, keratoconjunctivitis sicca, ophthalmia neonatorium, symblepharon, corneal sequestrum, eosinophilic keratitis and anterior uveitis. Diagnostic techniques discussed include: virus isolation, fluorescent antibody testing, serum neutralising titers, ELISA and polymerase chain reaction. Various therapies are also discussed.

  12. Gastrointestinal Manifestations of Cystic Fibrosis

    PubMed Central

    2016-01-01

    Cystic fibrosis has historically been considered a pulmonary disease, but with the increasing life expectancy of these patients, gastrointestinal manifestations are becoming more important. Furthermore, nutritional status is closely linked to pulmonary function and, thus, overall mortality. This article discusses gastrointestinal manifestations (which involve nutritional, pancreatic, hepatobiliary, and, in particular, gastrointestinal tract issues) of cystic fibrosis as well as management of the disease. In addition, the article discusses studies that have been critical to our understanding of gastrointestinal manifestations of cystic fibrosis. PMID:27330503

  13. Coronary Artery Manifestations of Fibromuscular Dysplasia

    PubMed Central

    Michelis, Katherine C.; Olin, Jeffrey W.; Kadian-Dodov, Daniella; d’Escamard, Valentina; Kovacic, Jason C.

    2015-01-01

    Fibromuscular dysplasia (FMD) involving the coronary arteries is an uncommon but important condition that can present as acute coronary syndrome, left ventricular dysfunction, or potentially sudden cardiac death. Although the classic angiographic “string of beads” that may be observed in renal artery FMD does not occur in coronary arteries, potential manifestations include spontaneous coronary artery dissection, distal tapering or long, smooth narrowing that may represent dissection, intramural hematoma, spasm, or tortuosity. Importantly, FMD must be identified in at least one other noncoronary arterial territory to attribute any coronary findings to FMD. Although there is limited evidence to guide treatment, many lesions heal spontaneously; thus, a conservative approach is generally preferred. The etiology is poorly understood, but there are ongoing efforts to better characterize FMD and define its genetic and molecular basis. This report reviews the clinical course of FMD involving the coronary arteries and provides guidance for diagnosis and treatment strategies. PMID:25190240

  14. Coronary artery manifestations of fibromuscular dysplasia.

    PubMed

    Michelis, Katherine C; Olin, Jeffrey W; Kadian-Dodov, Daniella; d'Escamard, Valentina; Kovacic, Jason C

    2014-09-09

    Fibromuscular dysplasia (FMD) involving the coronary arteries is an uncommon but important condition that can present as acute coronary syndrome, left ventricular dysfunction, or potentially sudden cardiac death. Although the classic angiographic "string of beads" that may be observed in renal artery FMD does not occur in coronary arteries, potential manifestations include spontaneous coronary artery dissection, distal tapering or long, smooth narrowing that may represent dissection, intramural hematoma, spasm, or tortuosity. Importantly, FMD must be identified in at least one other noncoronary arterial territory to attribute any coronary findings to FMD. Although there is limited evidence to guide treatment, many lesions heal spontaneously; thus, a conservative approach is generally preferred. The etiology is poorly understood, but there are ongoing efforts to better characterize FMD and define its genetic and molecular basis. This report reviews the clinical course of FMD involving the coronary arteries and provides guidance for diagnosis and treatment strategies.

  15. Various Manifestations of Hyperthyroidism in an Ambulatory Clinic: Case Studies

    PubMed Central

    Tripp, Warren; Rao, Vijaya; Creary, Ludlow B.

    1987-01-01

    This study reviews five cases of women with hyperthyroidism, three black women and two Hispanic women. Initially, two patients presented with voice changes, weight loss, and increased appetite. Only two patients presented with classical symptoms of hyperthyroidism. Examination showed all patients had diffusely enlarged thyroids and exaggerated reflexes. Two patients showed Graves' opthalmopathy. These cases document the variety of presentations of hyperthyroidism. Hence, a high index of suspicion must exist for this disease, even in the absence of a number of the classical manifestations of hyperthyroidism. When patients present to primary care centers with a constellation of symptoms, an examination of the thyroid gland is essential. PMID:3694696

  16. Adsorption mechanisms and effect of temperature in reversed-phase liquid chromatography-Meaning of the classical Van't Hoff plot in chromatography

    SciTech Connect

    Gritti, Fabrice; Guiochon, Georges A

    2006-07-01

    The effect of temperature on the adsorption and retention behaviors of a low molecular weight compound (phenol) on a C{sub 18}-bonded silica column (C{sub 18}-Sunfire, Waters) from aqueous solutions of methanol (20%) or acetonitrile (15%) was investigated. The results of the measurements were interpreted successively on the basis of the linear (i.e., overall retention factors) and the nonlinear (i.e., adsorption isotherms, surface heterogeneity, saturation capacities, and equilibrium constants) chromatographic methods. The confrontation of these two approaches confirmed the impossibility of a sound physical interpretation of the conventional Van't Hoff plot. The classical linear chromatography theory assumes that retention is determined by the equilibrium thermodynamics of analytes between a homogeneous stationary phase and a homogeneous mobile phase (although there may be two or several types of interactions). From values of the experimental retention factors in a temperature interval and estimates of the activity coefficients at infinite dilution in the same temperature interval provided by the UNIFAC group contribution method, evidence is provided that such a retention model cannot hold. The classical Van't Hoff plot appears meaningless and its linear behavior a mere accident. Results from nonlinear chromatography confirm these conclusions and provide explanations. The retention factors seem to fulfill the Van't Hoff equation, not the Henry constants corresponding to the different types of adsorption sites. The saturation capacities and the adsorption energies are clearly temperature dependent. The temperature dependence of these characteristics of the different assorption sites are different in aqueous methanol and acetonitrile solutions.

  17. [Oral manifestations in systemic diseases].

    PubMed

    Pedersen, Anne Marie Lynge; Jensen, Siri Beier

    2010-11-01

    Systemic diseases may affect the oral tissues, i.e. oral mucosa, salivary glands, teeth or bone, and oral manifestations will frequently present early, i.e. in association with (non-fulminant) systemic disease. Thus, recognition and proper diagnosis is essential to initiate appropriate treatment schedules. Key examples of systemic disease groups with oral manifestations include dermatological, inflammatory connective tissue diseases, haematological and inflammatory gastrointestinal diseases, as well as neurological and endocrine diseases.

  18. Cutaneous manifestations of child abuse.

    PubMed

    Kos, Liborka; Shwayder, Tor

    2006-01-01

    Dermatologists and child abuse are not frequently associated in the minds of most physicians. Yet the most common manifestations of child abuse are cutaneous. This article reviews cutaneous manifestations of physical abuse, including bruises, lacerations, abrasions, human bites, and burns. It also discusses ways that dermatologists can differentiate abusive injuries from accidental ones as well as from the many dermatologic conditions that can mimic child abuse. Finally, we review what actions the dermatologist should take when suspecting abuse in a patient.

  19. [Psychiatric manifestations in dementia: phenomenologic perspectives].

    PubMed

    Paquette, I

    1993-12-01

    The study of psychiatric manifestations in dementia has long been overshadowed by the more classical manifestations of the disease, such as memory loss and other cognitive deficits. In recent years, however, psychiatric symptoms as part of the demential process have attracted interest and research has become more specific. Clinicians are faced with diagnostic, treatment and management difficulties related to affective or psychotic symptoms, which account for much distress and morbidity. Several studies indicate that the prevalence of psychiatric manifestations in clinical populations of patients suffering from dementia is high: 15% to 30% for hallucinations, 15% to 30% for delusions, ten percent to 20% for major depression and 40% to 50% for depressed mood. These figures tend to confirm the hypothesis that psychiatric features in dementia are neither infrequent nor atypical. Thus, researchers have sought to link psychotic or depressive symptomatology with several clinical characteristics of dementia, namely stage, severity, prognosis or cognitive dysfunction. Some recent studies involving extensive neuropsychological evaluations indicate that subgroups of patients can be defined according to psychiatric criteria, as well as cognitive or neurological criteria. Unfortunately, results are inconsistent. Some of the contradictions in the literature are related to poorly defined terms and symptoms, a lack of reliable operational criteria, absence of validation of instruments and scales and heterogeneity of the populations studied. Ambiguous syndromes, such as pseudodementia, while illustrative of certain clinical situations, have not been helpful in categorizing demented patients. The author suggests that research focused on specific and clearly defined psychiatric symptoms in dementia will better serve our comprehension of mixed syndromes.

  20. Absolutely classical spin states

    NASA Astrophysics Data System (ADS)

    Bohnet-Waldraff, F.; Giraud, O.; Braun, D.

    2017-01-01

    We introduce the concept of "absolutely classical" spin states, in analogy to absolutely separable states of bipartite quantum systems. Absolutely classical states are states that remain classical (i.e., a convex sum of projectors on coherent states of a spin j ) under any unitary transformation applied to them. We investigate the maximal size of the ball of absolutely classical states centered on the maximally mixed state and derive a lower bound for its radius as a function of the total spin quantum number. We also obtain a numerical estimate of this maximal radius and compare it to the case of absolutely separable states.

  1. Nonzero Classical Discord

    NASA Astrophysics Data System (ADS)

    Gheorghiu, Vlad; de Oliveira, Marcos C.; Sanders, Barry C.

    2015-07-01

    Quantum discord is the quantitative difference between two alternative expressions for bipartite mutual information, given respectively in terms of two distinct definitions for the conditional entropy. By constructing a stochastic model of shared states, classical discord can be similarly defined, quantifying the presence of some stochasticity in the measurement process. Therefore, discord can generally be understood as a quantification of the system's state disturbance due to local measurements, be it quantum or classical. We establish an operational meaning of classical discord in the context of state merging with noisy measurement and thereby show the quantum-classical separation in terms of a negative conditional entropy.

  2. Skin Manifestations of Inflammatory Bowel Disease

    PubMed Central

    Huang, Brian L.; Chandra, Stephanie; Shih, David Quan

    2012-01-01

    Inflammatory bowel disease (IBD) is a disease that affects the intestinal tract via an inflammatory process. Patients who suffer from IBD often have diseases that affect multiple other organ systems as well. These are called extraintestinal manifestations and can be just as, if not more debilitating than the intestinal inflammation itself. The skin is one of the most commonly affected organ systems in patients who suffer from IBD. The scientific literature suggests that a disturbance of the equilibrium between host defense and tolerance, and the subsequent over-activity of certain immune pathways are responsible for the cutaneous disorders seen so frequently in IBD patients. The purpose of this review article is to give an overview of the types of skin diseases that are typically seen with IBD and their respective pathogenesis, proposed mechanisms, and treatments. These cutaneous disorders can manifest as metastatic lesions, reactive processes to the intestinal inflammation, complications of IBD itself, or side effects from IBD treatments; these can be associated with IBD via genetic linkage, common autoimmune processes, or other mechanisms that will be discussed in this article. Ultimately, it is important for healthcare providers to understand that skin manifestations should always be checked and evaluated for in patients with IBD. Furthermore, skin disorders can predate gastrointestinal symptoms and thus may serve as important clinical indicators leading physicians to earlier diagnosis of IBD. PMID:22347192

  3. Classical and Quantum Spreading of Position Probability

    ERIC Educational Resources Information Center

    Farina, J. E. G.

    1977-01-01

    Demonstrates that the standard deviation of the position probability of a particle moving freely in one dimension is a function of the standard deviation of its velocity distribution and time in classical or quantum mechanics. (SL)

  4. Pulmonary manifestations of sickle cell disease

    PubMed Central

    Siddiqui, A; Ahmed, S

    2003-01-01

    Pulmonary complications account for significant morbidity and mortality in patients with sickle cell disease. Clinical lung involvement manifests in two major forms: the acute chest syndrome and sickle cell chronic lung disease. Acute chest syndrome is characterised by fever, chest pain, and appearance of a new infiltrate on chest radiograph. Sickle cell chronic lung disease, on the other hand, manifests as radiographic interstitial abnormalities, impaired pulmonary function, and, in its most severe form, by the evidence of pulmonary hypertension. Progress has been made in understanding the pathophysiology and management of these complications. In this review the current knowledge of the mechanism, diagnosis, and treatment of pulmonary complications of sickle cell disease are discussed. PMID:12897216

  5. The Classics, Con Brio

    ERIC Educational Resources Information Center

    Hansen, James

    1978-01-01

    Sponsored by a consortium of 30 American universities, Rome's Intercollegiate Center for Classical Studies offers a year of study to American undergraduate classics majors. Instructors are also American and normally stay only a year; teaching assistants are always ex-students of the center. Extensive field trips are an important part of the…

  6. Classic-Ada(TM)

    NASA Technical Reports Server (NTRS)

    Valley, Lois

    1989-01-01

    The SPS product, Classic-Ada, is a software tool that supports object-oriented Ada programming with powerful inheritance and dynamic binding. Object Oriented Design (OOD) is an easy, natural development paradigm, but it is not supported by Ada. Following the DOD Ada mandate, SPS developed Classic-Ada to provide a tool which supports OOD and implements code in Ada. It consists of a design language, a code generator and a toolset. As a design language, Classic-Ada supports the object-oriented principles of information hiding, data abstraction, dynamic binding, and inheritance. It also supports natural reuse and incremental development through inheritance, code factoring, and Ada, Classic-Ada, dynamic binding and static binding in the same program. Only nine new constructs were added to Ada to provide object-oriented design capabilities. The Classic-Ada code generator translates user application code into fully compliant, ready-to-run, standard Ada. The Classic-Ada toolset is fully supported by SPS and consists of an object generator, a builder, a dictionary manager, and a reporter. Demonstrations of Classic-Ada and the Classic-Ada Browser were given at the workshop.

  7. Solvation Mechanism of Task-Specific Ionic Liquids in Water: A Combined Investigation Using Classical Molecular Dynamics and Density Functional Theory.

    PubMed

    Yuvaraj, Surya V J; Zhdanov, Ravil K; Belosludov, Rodion V; Belosludov, Vladimir R; Subbotin, Oleg S; Kanie, Kiyoshi; Funaki, Kenji; Muramatsu, Atsushi; Nakamura, Takashi; Kawazoe, Yoshiyuki

    2015-10-08

    The solvation behavior of task-specific ionic liquids (TSILs) containing a common, L-histidine derived imidazolium cation [C20H28N3O3](+) and different anions, bromide-[Br](-) and bis(trifluoromethylsulfonyl)amide-[NTF2](-), in water is examined, computationally. These amino acid functionalized ionic liquids (ILs) are taken into account because of their ability to react with rare earth metal salts. It has been noted that the TSIL with [Br](-) is more soluble than its counterpart TSIL with [NTF2](-), experimentally. In this theoretical work, the combined classical molecular dynamics (CMD) and density functional theory (DFT) calculations are performed to study the behavior of the bulk phase of these two TSILs in the vicinity of water (H2O) molecules with different concentrations. Initially, all the constructed systems are equilibrated using the CMD method. The final structures of the equilibrated systems are extracted for DFT calculations. Under CMD operation, the radial distribution function (RDF) plots and viscosity of TSILs are analyzed to understand the effect of water on TSILs. In the DFT regime, binding energy per H2O, charge transfer, charge density mapping, and electronic density of states (EDOS) analyses are done. The CMD results along with the DFT results are consolidated to support the hydrophilic and hydrophobic nature of the TSILs. Interestingly, we have found a strong correlation between the viscosity and the EDOS results that leads to an understanding of the hydration properties of the TSILs.

  8. Classical/Non‐classical Polyoxometalate Hybrids

    PubMed Central

    Santiago‐Schübel, Beatrix; Willbold, Sabine; Heß, Volkmar

    2016-01-01

    Abstract Two polyanions [SeI V 2PdII 4WVI 14O56H]11− and [SeI V 4PdII 4WVI 28O108H12]12− are the first hybrid polyoxometalates in which classical (Group 5/6 metal based) and non‐classical (late transition‐metal based) polyoxometalate units are joined. Requiring no supporting groups, this co‐condensation of polyoxotungstate and isopolyoxopalladate constituents also provides a logical link between POM‐PdII coordination complexes and the young subclass of polyoxopalladates. Solid‐state, solution, and gas‐phase studies suggest interesting specific reactivities for these hybrids and point to several potential derivatives and functionalization strategies. PMID:27617918

  9. Clinical exuberance of classic Kaposi's sarcoma and response to radiotherapy.

    PubMed

    Trujillo, Jeniffer Muñoz; Alves, Natália Ribeiro de Magalhães; Medeiros, Paula Mota; Azulay-Abulafia, Luna; Alves, Maria de Fátima Guimarães Scotelaro; Gripp, Alexandre Carlos

    2015-01-01

    Kaposi's sarcoma (KS) is a multicentric vascular neoplasm, with cutaneous and extracutaneous involvement. Different clinical and epidemiological variants have been identified. The classic form is manifested mainly in elderly men with indolent and long-term evolution, with lesions localized primarily in the lower extremities. We present two cases of classic Kaposi's sarcoma (CKS) in two female patients with extensive, exuberant skin involvement and rapid evolution, with good response to radiotherapy.

  10. Classical simulation of entangled states

    NASA Astrophysics Data System (ADS)

    Bharath, H. M.; Ravishankar, V.

    2014-06-01

    Characterization of nonclassicality or quantumness of a state is fundamental to foundations of quantum mechanics and quantum information. At the heart of the problem is the question whether there exist classical systems—howsoever complicated—that can mimic a given quantum state. Whilst this has been traditionally addressed through the violation of Bell inequality or nonseparability, we show that it is possible to go beyond them, by introducing the concept of classical simulation. Focusing on the two-qubit case, we show that, while for pure states, classical simulability is equivalent to existence of a local hidden variable (LHV) model, the conditions for simulability can be weaker for mixed states, demanding what we call only a generalized LHV description. Consequently, quantum states which defy a classical simulation—which we call exceptional—may require conditions which are more stringent than violation of Bell inequalities. We illustrate these features with a number of representative examples and discuss the underlying reasons, by employing fairly simple arguments.

  11. Reflections on the mechanical structure of the base of the skull and on the face. Part 1: Classical theories, observed structures.

    PubMed

    Ferré, J C; Chevalier, C; Robert, R; Degrez, J; Le Cloarec, A Y; Legoux, R; Orio, E; Barbin, J Y

    1989-01-01

    Using thick sections of the base of the skull and face their mechanical structure is viewed from the engineering aspect and the anatomic solutions evolved are compared with those selected by Aerospatiale engineers for the concept and development of the Airbus. It is concluded that the anterior and middle cranial fossae, together with the face, constitute an inseparable mechanical assembly each of whose component units participate in the rigidity of the others. Since this mechanical assembly must provide maximal rigidity for minimal weight, this suggests that aeronautical solutions should throw much light on the detail of construction of the skull and face. Indeed, the rigidity and lightness of the latter are obtained by means of solutions familiar in aeronautics: the reliance on thin-shelled beams with a honeycomb filling, the diploe analogous to a preconstrained composite or sandwich structure, a system of frames, struts and stiffeners, and the use of fillets at the sites of junction of struts.

  12. Structural basis for dual-inhibition mechanism of a non-classical Kazal-type serine protease inhibitor from horseshoe crab in complex with subtilisin.

    PubMed

    Shenoy, Rajesh T; Thangamani, Saravanan; Velazquez-Campoy, Adrian; Ho, Bow; Ding, Jeak Ling; Sivaraman, J

    2011-04-26

    Serine proteases play a crucial role in host-pathogen interactions. In the innate immune system of invertebrates, multi-domain protease inhibitors are important for the regulation of host-pathogen interactions and antimicrobial activities. Serine protease inhibitors, 9.3-kDa CrSPI isoforms 1 and 2, have been identified from the hepatopancreas of the horseshoe crab, Carcinoscorpius rotundicauda. The CrSPIs were biochemically active, especially CrSPI-1, which potently inhibited subtilisin (Ki = 1.43 nM). CrSPI has been grouped with the non-classical Kazal-type inhibitors due to its unusual cysteine distribution. Here we report the crystal structure of CrSPI-1 in complex with subtilisin at 2.6 Å resolution and the results of biophysical interaction studies. The CrSPI-1 molecule has two domains arranged in an extended conformation. These two domains act as heads that independently interact with two separate subtilisin molecules, resulting in the inhibition of subtilisin activity at a ratio of 1:2 (inhibitor to protease). Each subtilisin molecule interacts with the reactive site loop from each domain of CrSPI-1 through a standard canonical binding mode and forms a single ternary complex. In addition, we propose the substrate preferences of each domain of CrSPI-1. Domain 2 is specific towards the bacterial protease subtilisin, while domain 1 is likely to interact with the host protease, Furin. Elucidation of the structure of the CrSPI-1: subtilisin (1∶2) ternary complex increases our understanding of host-pathogen interactions in the innate immune system at the molecular level and provides new strategies for immunomodulation.

  13. Structural Basis for Dual-Inhibition Mechanism of a Non-Classical Kazal-Type Serine Protease Inhibitor from Horseshoe Crab in Complex with Subtilisin

    SciTech Connect

    Shenoy, Rajesh T.; Thangamani, Saravanan; Velazquez-Campoy, Adrian; Ho, Bow; Ding, Jeak Ling; Sivaraman, J.; Kursula, Petri

    2011-04-26

    Serine proteases play a crucial role in host-pathogen interactions. In the innate immune system of invertebrates, multi-domain protease inhibitors are important for the regulation of host-pathogen interactions and antimicrobial activities. Serine protease inhibitors, 9.3-kDa CrSPI isoforms 1 and 2, have been identified from the hepatopancreas of the horseshoe crab, Carcinoscorpius rotundicauda. The CrSPIs were biochemically active, especially CrSPI-1, which potently inhibited subtilisin (Ki=1.43 nM). CrSPI has been grouped with the non-classical Kazal-type inhibitors due to its unusual cysteine distribution. Here we report the crystal structure of CrSPI-1 in complex with subtilisin at 2.6 Å resolution and the results of biophysical interaction studies. The CrSPI-1 molecule has two domains arranged in an extended conformation. These two domains act as heads that independently interact with two separate subtilisin molecules, resulting in the inhibition of subtilisin activity at a ratio of 1:2 (inhibitor to protease). Each subtilisin molecule interacts with the reactive site loop from each domain of CrSPI-1 through a standard canonical binding mode and forms a single ternary complex. In addition, we propose the substrate preferences of each domain of CrSPI-1. Domain 2 is specific towards the bacterial protease subtilisin, while domain 1 is likely to interact with the host protease, Furin. Elucidation of the structure of the CrSPI-1: subtilisin (1:2) ternary complex increases our understanding of host-pathogen interactions in the innate immune system at the molecular level and provides new strategies for immunomodulation.

  14. More Gamma More Predictions: Gamma-Synchronization as a Key Mechanism for Efficient Integration of Classical Receptive Field Inputs with Surround Predictions

    PubMed Central

    Vinck, Martin; Bosman, Conrado A.

    2016-01-01

    During visual stimulation, neurons in visual cortex often exhibit rhythmic and synchronous firing in the gamma-frequency (30–90 Hz) band. Whether this phenomenon plays a functional role during visual processing is not fully clear and remains heavily debated. In this article, we explore the function of gamma-synchronization in the context of predictive and efficient coding theories. These theories hold that sensory neurons utilize the statistical regularities in the natural world in order to improve the efficiency of the neural code, and to optimize the inference of the stimulus causes of the sensory data. In visual cortex, this relies on the integration of classical receptive field (CRF) data with predictions from the surround. Here we outline two main hypotheses about gamma-synchronization in visual cortex. First, we hypothesize that the precision of gamma-synchronization reflects the extent to which CRF data can be accurately predicted by the surround. Second, we hypothesize that different cortical columns synchronize to the extent that they accurately predict each other’s CRF visual input. We argue that these two hypotheses can account for a large number of empirical observations made on the stimulus dependencies of gamma-synchronization. Furthermore, we show that they are consistent with the known laminar dependencies of gamma-synchronization and the spatial profile of intercolumnar gamma-synchronization, as well as the dependence of gamma-synchronization on experience and development. Based on our two main hypotheses, we outline two additional hypotheses. First, we hypothesize that the precision of gamma-synchronization shows, in general, a negative dependence on RF size. In support, we review evidence showing that gamma-synchronization decreases in strength along the visual hierarchy, and tends to be more prominent in species with small V1 RFs. Second, we hypothesize that gamma-synchronized network dynamics facilitate the emergence of spiking output that

  15. Classical and semiclassical aspects of chemical dynamics

    SciTech Connect

    Gray, S.K.

    1982-08-01

    Tunneling in the unimolecular reactions H/sub 2/C/sub 2/ ..-->.. HC/sub 2/H, HNC ..-->.. HCN, and H/sub 2/CO ..-->.. H/sub 2/ + CO is studied with a classical Hamiltonian that allows the reaction coordinate and transverse vibrational modes to be considered directly. A combination of classical perturbation theory and the semiclassical WKB method allows tunneling probabilities to be obtained, and a statistical theory (RRKM) is used to construct rate constants for these reactions in the tunneling regime. In this fashion, it is found that tunneling may be important, particularly for low excitation energies. Nonadiabatic charge transfer in the reaction Na + I ..-->.. Na /sup +/ + I/sup -/ is treated with classical trajectories based on a classical Hamiltonian that is the analogue of a quantum matrix representation. The charge transfer cross section obtained is found to agree reasonably well with the exact quantum results. An approximate semiclassical formula, valid at high energies, is also obtained. The interaction of radiation and matter is treated from a classical viewpoint. The excitation of an HF molecule in a strong laser is described with classical trajectories. Quantum mechanical results are also obtained and compared to the classical results. Although the detailed structure of the pulse time averaged energy absorption cannot be reproduced classically, classical mechanics does predict the correct magnitude of energy absorption, as well as certain other qualitative features. The classical behavior of a nonrotating diatomic molecule in a strong laser field is considered further, by generating a period advance map that allows the solution over many periods of oscillation of the laser to be obtained with relative ease. Classical states are found to form beautiful spirals in phase space as time progresses. A simple pendulum model is found to describe the major qualitative features. (WHM)

  16. Cutaneous manifestations of human toxocariasis.

    PubMed

    Gavignet, Béatrice; Piarroux, Renaud; Aubin, François; Millon, Laurence; Humbert, Philippe

    2008-12-01

    Human toxocariasis is a parasitic disease characterized by the presence of larvae of the genus Toxocara in human tissues. T canis and T cati, the adult roundworms of which are found in dog and cat intestines, respectively, are the most common causative agents of the disease. Toxocaral larvae usually cause two severe syndromes: visceral larva migrans and ocular larva migrans, depending on the location of the larvae. Two other syndromes, covert toxocariasis and common toxocariasis, which are less typical and not as severe, have also been described. During the last two decades, cutaneous manifestations such as chronic urticaria, chronic pruritus, and miscellaneous eczema, in patients with Toxocara antibodies, have been studied by different authors. In some cases, these cutaneous manifestations are the only signs indicating the presence of the disease, and they are cured after antihelmintic treatment when there is good patient compliance. In this review, we focus on these particular skin manifestations regarding their clinical description, diagnosis, and treatment.

  17. Neurocutaneous Manifestations of Genetic Mosaicism

    PubMed Central

    van Steensel, Maurice A. M.

    2015-01-01

    Genetic mosaicism is defined as the presence of two or more genetically distinct cell populations in a single individual. Ever more disorders are found to be manifestations of mosaicism and together constitute a significant proportion of the morbidity confronting pediatric specialists. An emerging category is that of overgrowth syndromes with skin manifestations and neurological or developmental abnormalities, such as the well-known Proteus syndrome. In recent years, we have seen dramatic advances in our understanding of these disorders and we now know the genetic basis of many of them. This has profound consequences for diagnosis, counselling, and even treatment, with therapies targeted to specific pathways becoming available for clinical use. Recognizing such overgrowth syndromes, therefore, is more important than ever. Fortunately, their skin manifestations can provide important diagnostic clues when evaluated in the entire phenotypic context. In this review, I provide an overview of the most frequently seen mosaic neurocutaneous phenotypes and discuss their molecular basis. PMID:27617125

  18. [Cardiovascular manifestations of human toxocariasis].

    PubMed

    Bolívar-Mejía, Adrián; Rodríguez-Morales, Alfonso J; Paniz-Mondolfi, Alberto E; Delgado, Olinda

    2013-01-01

    Toxocariasis is a parasitic infection produced by helminths that cannot reach their adult stage in humans. For their etiological species (Toxocara canis and Toxocara cati), man is a paratenic host. Infection by such helminths can produce a variety of clinical manifestations, such as: visceral larvae migrans syndrome, ocular larvae migrans syndrome and covert toxocariasis. In the visceral larvae migrans syndrome, the organs that are mainly involved include liver, lungs, skin, nervous system, muscles, kidneys and the heart. Regarding the latter, the importance of cardiovascular manifestations in toxocariasis, as well as its clinical relevance, has increasingly begun to be recognized. The current article is based on a systematic information search, focused mainly on the clinical and pathological aspects of cardiovascular manifestations in toxocariasis, including its pathophysiology, laboratory findings, diagnosis and therapeutical options, with the objective of highlighting its importance as a zoonosis and its relevance to the fields of cardiovascular medicine in adults and children.

  19. Classical decoherence in a nanomechanical resonator

    NASA Astrophysics Data System (ADS)

    Maillet, Olivier; Fefferman, Andrew; Gazizulin, Rasul; Godfrin, Henri; Bourgeois, Olivier; Collin, Eddy; ULT Grenoble Team

    Decoherence can be viewed either in its quantum picture, where it stands for the loss of phase coherence of a superposition state, or as its classical equivalent, where the phase of an oscillating signal is smeared due to frequency fluctuations. Little is known about quantum coherence of mechanical systems, as opposed to electromagnetic degrees of freedom. Indeed the bridge between quantum and classical physics is under intense investigation, using in particular classical nanomechanical analogues of quantum phenomena. Here we report on a model experiment in which the coherence of a high quality silicon-nitride mechanical resonator is defined in the classical picture. Its intrinsic properties are characterized over an unprecedentedly large dynamic range. By engineering frequency fluctuations, we can create artificial pure dephasing and study its effects on the dynamics of the system. Finally, we develop the methods to characterize pure dephasing that can be applied to a wide range of mechanical devices.

  20. From classical psychodynamics to evidence synthesis: the motif of repression and a contemporary understanding of a key mediatory mechanism in psychosis.

    PubMed

    Fleming, Mick P; Martin, Colin R

    2012-06-01

    The stress vulnerability model has proven to be a politically important model for two reasons. It has provided the framework that defines a temporal and dynamic process whereby a person's uniquely determined biopsychosocial vulnerability to schizophrenia symptoms interacts with his or her capacity to manage stress and the amount and type of stress experienced in such a way that the person experiences schizophrenia symptoms. Second, the development of this framework promoted the notion of inherited and acquired vulnerability. Implicit was that vulnerability was individually determined and that there was a role for psychosocial factors in the development/maintenance of schizophrenia symptoms. This proved to be a catalyst for the development of studies implicating psychosocial factors in the etiology of schizophrenia symptoms. Studies derived from cognitive-behavioral theories have proven the most successful in identifying thinking patterns, emotional disturbances, and neurocognitive and defensive vulnerability factors inherent in the development of schizophrenia symptoms. Historically, within the psychoanalytic school there has been debate regarding the role of repressive coping mechanisms in schizophrenia development. Psychoanalytic theories have always appeared incapable of providing etiologic explanations of schizophrenia symptoms, with the possible exception of Melanie Klein, than other more salient psychosocial schools. Mechanisms within the process of repressive coping are consistent with evidence and mechanisms supporting the stress vulnerability models and existing cognitive-behavioral theories regarding development of paranoid delusions. These mechanisms are less consistent with social cognitive explanations of schizophrenia symptoms.

  1. Classical-Quantum Limits

    NASA Astrophysics Data System (ADS)

    Oliynyk, Todd A.

    2016-12-01

    We introduce a new approach to analyzing the interaction between classical and quantum systems that is based on a limiting procedure applied to multi-particle Schrödinger equations. The limit equations obtained by this procedure, which we refer to as the classical-quantum limit, govern the interaction between classical and quantum systems, and they possess many desirable properties that are inherited in the limit from the multi-particle quantum system. As an application, we use the classical-quantum limit equations to identify the source of the non-local signalling that is known to occur in the classical-quantum hybrid scheme of Hall and Reginatto. We also derive the first order correction to the classical-quantum limit equation to obtain a fully consistent first order approximation to the Schrödinger equation that should be accurate for modeling the interaction between particles of disparate mass in the regime where the particles with the larger masses are effectively classical.

  2. Hepatic manifestations of non-steroidal inflammatory bowel disease therapy

    PubMed Central

    Hirten, Robert; Sultan, Keith; Thomas, Ashby; Bernstein, David E

    2015-01-01

    Inflammatory bowel disease (IBD) is composed of Crohn’s disease and ulcerative colitis and is manifested by both bowel-related and extraintestinal manifestations. Recently the number of therapeutic options available to treat IBD has dramatically increased, with each new medication having its own mechanism of action and side effect profile. A complete understanding of the hepatotoxicity of these medications is important in order to distinguish these complications from the hepatic manifestations of IBD. This review seeks to evaluate the hepatobiliary complications of non-steroid based IBD medications and aide providers in the recognition and management of these side-effects. PMID:26644815

  3. Skin manifestations of child abuse.

    PubMed

    Ermertcan, Aylin Turel; Ertan, Pelin

    2010-01-01

    Child abuse is a major public health problem all over the world. There are four major types of abuse: physical abuse, sexual abuse, emotional abuse and neglect. The most common manifestations of child abuse are cutaneous and their recognition; and differential diagnosis is of great importance. Clinicians, especially dermatologists, should be alert about the skin lesions of child abuse. In the diagnosis and management of child abuse, a multidisciplinary approach with ethical and legal procedures is necessary. In this manuscript, cutaneous manifestations of physical, sexual, emotional abuse and neglect are reviewed and discussed.

  4. Hematological manifestations of nephropathic cystinosis.

    PubMed

    Emadi, Ashkan; Burns, Kathleen H; Confer, Bradley; Borowitz, Michael J; Streiff, Michael B

    2008-01-01

    Pancytopenia is an uncommon manifestation of cystinosis, a congenital lysosomal storage disease. We describe a 34-year-old patient with nephropathic cystinosis with multisystem involvement who developed progressive bone marrow failure after renal transplantation. Bone marrow examination demonstrated widespread deposition of cystine crystals in histiocytes and in the background. We review the literature on the hematologic manifestations of cystinosis and discuss the available treatment options for patients with bone marrow failure secondary to cystine accumulation. The availability of effective oral therapy and the limited activity of hematopoietic growth factors in these patients highlight the importance of bone marrow examination early in the evaluation of cystinosis patients with abnormal blood counts.

  5. Quantum physics of classical waves in plasma

    NASA Astrophysics Data System (ADS)

    Dodin, I. Y.

    2012-10-01

    The Lagrangian approach to plasma wave physics is extended to a universal nonlinear theory which yields generic equations invariant with respect to the wave nature. The traditional understanding of waves as solutions of the Maxwell-Vlasov system is abandoned. Oscillations are rather treated as physical entities, namely, abstract vectors |ψ> in a specific Hilbert space. The invariant product <ψ|ψ> is the total action and has the sign of the oscillation energy. The action density is then an operator. Projections of the corresponding operator equation generate assorted wave kinetic equations; the nonlinear Wigner-Moyal equation is just one example and, in fact, may be more delicate than commonly assumed. The linear adiabatic limit of this classical theory leads to quantum mechanics in its general form. The action conservation theorem, together with its avatars such as Manley-Rowe relations, then becomes manifest and in partial equilibrium can modify statistical properties of plasma fluctuations. In the quasi-monochromatic limit geometrical optics (GO) is recovered and can as well be understood as a particular field theory in its own right. For linear waves, the energy-momentum equations, in both canonical and (often) kinetic form, then follow automatically, even without a reference to electromagnetism. Yet for waves in plasma the general GO Lagrangian is also derived explicitly, in terms of single-particle oscillation-center Hamiltonians. Applications to various plasma waves are then discussed with an emphasis on the advantages of an abstract theory. Specifically covered are nonlinear dispersion, dynamics, and stability of BGK modes, and also other wave transformations in laboratory and cosmological plasmas.

  6. No return to classical reality

    NASA Astrophysics Data System (ADS)

    Jennings, David; Leifer, Matthew

    2016-01-01

    At a fundamental level, the classical picture of the world is dead, and has been dead now for almost a century. Pinning down exactly which quantum phenomena are responsible for this has proved to be a tricky and controversial question, but a lot of progress has been made in the past few decades. We now have a range of precise statements showing that whatever the ultimate laws of nature are, they cannot be classical. In this article, we review results on the fundamental phenomena of quantum theory that cannot be understood in classical terms. We proceed by first granting quite a broad notion of classicality, describe a range of quantum phenomena (such as randomness, discreteness, the indistinguishability of states, measurement-uncertainty, measurement-disturbance, complementarity, non-commutativity, interference, the no-cloning theorem and the collapse of the wave-packet) that do fall under its liberal scope, and then finally describe some aspects of quantum physics that can never admit a classical understanding - the intrinsically quantum mechanical aspects of nature. The most famous of these is Bell's theorem, but we also review two more recent results in this area. Firstly, Hardy's theorem shows that even a finite-dimensional quantum system must contain an infinite amount of information, and secondly, the Pusey-Barrett-Rudolph theorem shows that the wave function must be an objective property of an individual quantum system. Besides being of foundational interest, results of this sort now find surprising practical applications in areas such as quantum information science and the simulation of quantum systems.

  7. A Classical Science Transformed.

    ERIC Educational Resources Information Center

    Kovalevsky, Jean

    1979-01-01

    Describes how satellites and other tools of space technology have transformed classical geodesy into the science of space geodynamics. The establishment and the activities of the French Center for Geodynamic and Astronomical Research Studies (CERGA) are also included. (HM)

  8. Morphologic manifestations of testicular and epididymal toxicity

    PubMed Central

    Vidal, Justin D; Whitney, Katharine M

    2014-01-01

    Histopathologic examination of the testis is the most sensitive means to detect effects on spermatogenesis; however, the complexity of testicular histology, interrelatedness of cell types within the testis, and long duration of spermatogenesis can make assessment of a testicular toxicant challenging. A thorough understanding of the histology and morphologic manifestations of response to injury is critical to successfully identify a testicular effect and to begin to understand the underlying mechanism of action. The basic patterns of response to xenobiotic-induced injury to the testis and epididymis are detailed and discussed. PMID:26413388

  9. Dark matter: Observational manifestation and experimental searches

    NASA Astrophysics Data System (ADS)

    Vavilova, I. B.; Bolotin, Yu. L.; Boyarsky, A. M.; Danevich, F. A.; Kobychev, V. V.; Tretyak, V. I.; Babyk, Iu. V.; Iakubovskyi, D. A.; Hnatyk, B. I.; Sergeev, S. G

    2015-08-01

    This monograph is the third issue of a three volume edition under the general title "Dark Energy and Dark Matter in the Universe". The authors discuss the astrophysical direct and indirect manifestation and properties of dark matter in galaxies, galaxy clusters and groups; the different mechanisms of energy exchange between dark energy and dark matter that expand the capabilities of the Standard Cosmological Model; the experimental search for dark matter particle candidates (including the sterile neutrinos, solar axions,weakly-interacting massive particles, and superheavy dark matter particles) using space, ground-based, and underground observatories.

  10. Quantum simulation of classical thermal states.

    PubMed

    Dür, W; Van den Nest, M

    2011-10-21

    We establish a connection between ground states of local quantum Hamiltonians and thermal states of classical spin systems. For any discrete classical statistical mechanical model in any spatial dimension, we find an associated quantum state such that the reduced density operator behaves as the thermal state of the classical system. We show that all these quantum states are unique ground states of a universal 5-body local quantum Hamiltonian acting on a (polynomially enlarged) qubit system on a 2D lattice. The only free parameters of the quantum Hamiltonian are coupling strengths of two-body interactions, which allow one to choose the type and dimension of the classical model as well as the interaction strength and temperature. This opens the possibility to study and simulate classical spin models in arbitrary dimension using a 2D quantum system.

  11. Parasitic Diseases With Cutaneous Manifestations.

    PubMed

    Ash, Mark M; Phillips, Charles M

    2016-01-01

    Parasitic diseases result in a significant global health burden. While often thought to be isolated to returning travelers, parasitic diseases can also be acquired locally in the United States. Therefore, clinicians must be aware of the cutaneous manifestations of parasitic diseases to allow for prompt recognition, effective management, and subsequent mitigation of complications. This commentary also reviews pharmacologic treatment options for several common diseases.

  12. ENT manifestations of Wegeners granulomatosis.

    PubMed

    Sharma, Arpit; Deshmukh, Shraddha; Dabholkar, Jyoti

    2013-01-01

    Wegeners granulomatosis is a necrotizing granulomatous vasculitis with multisystemic involvement. We present two cases of Wegener's presenting with otological manifestations as the first symptom. These symptoms are subtle and diagnosis may be easily overlooked. Hence a high index of suspicion is required. Early diagnosis and treatment goes a long way in improving the outcomes and in preventing further complications.

  13. Electrocardiographic enigma of a classical disease: pellagra.

    PubMed

    Kavitha, B; Balasubramanian, R; Kumar, Thirumal

    2012-10-01

    Pellagra is caused by a deficiency of niacin. It is endemic in Africa and Asia where the staple diet of the many refugees or displaced people is corn-based and, therefore, nicotinic acid-deficient. It is also frequently seen in developed countries among chronic alcoholics or, occasionally, those suffering from anorexia nervosa. The usual manifestations are diarrhoea, dementia and dermatitis (the 3Ds), which if left untreated may lead to death. Cardiac manifestations and electrocardiographic changes are rarely seen in those suffering from pellagra. We present a case of pellagra in an alcoholic who presented with the classical rash over the upper limbs along with electrocardiographic changes but without any cardiac symptoms, both of which resolved dramatically after he had been given niacin supplements.

  14. Quantum-mechanical vs. semi-classical spectral-line widths and shifts from the line core in the non-impact region for the Ar-perturbed/ K-radiator system

    NASA Astrophysics Data System (ADS)

    Kreye, W. C.

    2007-09-01

    New quantum-mechanical (QM) and semi-classical (SC) shifts (d's) and widths (HWHM's, w's) were measured from the line core of computed full spectral-line shapes for the Ar-perturbed/K-radiator system (K/Ar). The initial state of our model was based on a 4p2P3/2,1/2 pseudo-potential for the K/Ar system, and the final state on a zero potential. The Fourier transform of the line shape formed the basis for the computations. Excellent agreement was found between the QM and SC values of d and of w in a high-pressure (P) non-impact region, which was characterized by a √P dependence of w and a P dependence of d. These agreements were shown to be another example of a correspondence between classical (SC) quantities and QM quantities in the limit of large quantum numbers. Typically at P=1×106 Torr and T=400 K, wQM=448 cm-1 and wSC=479 cm-1, where the deviation from the mean is ±3.3%. Also, dQM=-3815 cm-1 and dSC=-3716 cm-1, where the deviation from the mean is ±1.3%. A new general method was formulated which yielded a definite pressure P0, which was defined as an upper limit to the low-pressure impact approximation and a lower limit to the non-impact region.

  15. HIV-1 Reverse Transcriptase Still Remains a New Drug Target: Structure, Function, Classical Inhibitors, and New Inhibitors with Innovative Mechanisms of Actions

    PubMed Central

    Esposito, Francesca; Corona, Angela; Tramontano, Enzo

    2012-01-01

    During the retrotranscription process, characteristic of all retroviruses, the viral ssRNA genome is converted into integration-competent dsDNA. This process is accomplished by the virus-coded reverse transcriptase (RT) protein, which is a primary target in the current treatments for HIV-1 infection. In particular, in the approved therapeutic regimens two classes of drugs target RT, namely, nucleoside RT inhibitors (NRTIs) and nonnucleoside RT inhibitors (NNRTIs). Both classes inhibit the RT-associated polymerase activity: the NRTIs compete with the natural dNTP substrate and act as chain terminators, while the NNRTIs bind to an allosteric pocket and inhibit polymerization noncompetitively. In addition to these two classes, other RT inhibitors (RTIs) that target RT by distinct mechanisms have been identified and are currently under development. These include translocation-defective RTIs, delayed chain terminators RTIs, lethal mutagenesis RTIs, dinucleotide tetraphosphates, nucleotide-competing RTIs, pyrophosphate analogs, RT-associated RNase H function inhibitors, and dual activities inhibitors. This paper describes the HIV-1 RT function and molecular structure, illustrates the currently approved RTIs, and focuses on the mechanisms of action of the newer classes of RTIs. PMID:22778958

  16. 40 CFR 761.215 - Manifest discrepancies.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... delivery of the waste to the first transporter designated on the manifest prepared under paragraph (e) or... PROHIBITIONS PCB Waste Disposal Records and Reports § 761.215 Manifest discrepancies. (a) Manifest... quantity or type of PCB waste designated on the manifest or shipping paper, and the quantity and type...

  17. Coherent quantum states from classical oscillator amplitudes

    NASA Astrophysics Data System (ADS)

    Briggs, John S.; Eisfeld, Alexander

    2012-05-01

    In the first days of quantum mechanics Dirac pointed out an analogy between the time-dependent coefficients of an expansion of the Schrödinger equation and the classical position and momentum variables solving Hamilton's equations. Here it is shown that the analogy can be made an equivalence in that, in principle, systems of classical oscillators can be constructed whose position and momenta variables form time-dependent amplitudes which are identical to the complex quantum amplitudes of the coupled wave function of an N-level quantum system with real coupling matrix elements. Hence classical motion can reproduce quantum coherence.

  18. Factorizations of one-dimensional classical systems

    SciTech Connect

    Kuru, Senguel; Negro, Javier

    2008-02-15

    A class of one-dimensional classical systems is characterized from an algebraic point of view. The Hamiltonians of these systems are factorized in terms of two functions that together with the Hamiltonian itself close a Poisson algebra. These two functions lead directly to two time-dependent integrals of motion from which the phase motions are derived algebraically. The systems so obtained constitute the classical analogues of the well known factorizable one-dimensional quantum mechanical systems.

  19. Bohmian trajectory from the "classical" Schrödinger equation.

    PubMed

    Sengupta, Santanu; Khatua, Munmun; Chattaraj, Pratim Kumar

    2014-12-01

    The quantum-classical correspondence is studied for a periodically driven quartic oscillator exhibiting integrable and chaotic dynamics, by studying the Bohmian trajectory of the corresponding "classical" Schrödinger equation. Phase plots and the Kolmogorov-Sinai entropy are computed and compared with the classical trajectory as well as the Bohmian trajectory obtained from the time dependent Schrödinger equation. Bohmian mechanics at the classical limit appears to mimick the behavior of a dissipative dynamical system.

  20. Combined linear response quantum mechanics and classical electrodynamics (QM/ED) method for the calculation of surface-enhanced Raman spectra.

    PubMed

    Mullin, Jonathan; Schatz, George C

    2012-03-01

    A multiscale method is presented that allows for evaluation of plasmon-enhanced optical properties of nanoparticle/molecule complexes with no additional cost compared to standard electrodynamics (ED) and linear response quantum mechanics (QM) calculations for the particle and molecule, respectively, but with polarization and orientation effects automatically described. The approach first calculates the total field of the nanoparticle by ED using the finite difference time domain (FDTD) method. The field intensity in the frequency domain as a function of distance from the nanoparticle is calculated via a Fourier transform. The molecular optical properties are then calculated with QM in the frequency domain in the presence of the total field of the nanoparticle. Back-coupling due to dipolar reradiation effects is included in the single-molecule plane wave approximation. The effects of polarization and partial orientation averaging are considered. The QM/ED method is evaluated for the well-characterized test case of surface-enhanced Raman scattering (SERS) of pyridine bound to silver, as well as for the resonant Raman chromophore rhodamine 6G. The electromagnetic contribution to the enhancement factor is 10(4) for pyridine and 10(2) for rhodamine 6G.

  1. Assessment of Parkinson Disease Manifestations

    PubMed Central

    Perlmutter, Joel S.

    2010-01-01

    Parkinson disease (PD) is a progressive neurologic condition that causes motor and non-motor manifestations. Treatment provides symptomatic benefit but no current treatment has been proven to slow disease progression. Research studies of PD require a means of rating the severity of disease by measurement of motor manifestations, assessment of ability to perform daily functional activities, and symptomatic response to medication. The most common rating scales are the Unified Parkinson Disease Rating Scale (UPDRS), Hoehn and Yahr staging, and the Schwab and England rating of activities of daily living. Each of these rating scales are described, including detailed instructions on how to implement these ratings. Although these are the most widely applied rating scales of PD, there are still substantial limitations to these scales that must be considered when using them for research. Finally, some common applications of these scales are described. PMID:19802812

  2. Porphyria and its neurologic manifestations.

    PubMed

    Tracy, Jennifer A; Dyck, P James B

    2014-01-01

    Porphyrias are rare disorders resulting from a defect in the heme biosynthetic pathway. They can produce significant disease of both the peripheral and central nervous systems, in addition to other organ systems, with acute intermittent porphyria, hereditary coproporphyria, and variegate porphyria as the subtypes associated with neurologic manifestations. The presence of a motor-predominant peripheral neuropathy (axonal predominant), accompanied by gastrointestinal distress and neuropsychiatric manifestations, should be a strong clue to the diagnosis of porphyria. Clinical confirmation can be made through evaluation of urine porphyrins during an exacerbation of disease. While hematin is helpful for acute treatment, long-term effective management requires avoidance of overstimulation of the cytochrome P450 pathway, as well as other risk factor control.

  3. Orofacial manifestations of systemic sclerosis.

    PubMed

    Veale, B J; Jablonski, R Y; Frech, T M; Pauling, J D

    2016-09-23

    Systemic sclerosis (SSc) is a multisystem disease of unknown aetiology characterised by microangiopathy, dysregulated immune function and tissue remodelling, which commonly involves the oral cavity. Orofacial manifestations of SSc contribute greatly to overall disease burden and yet are regularly overlooked and under-treated. This may reflect a pre-occupation amongst rheumatology clinicians on potentially life-threatening internal organ involvement, but is also a consequence of insufficient engagement between rheumatologists and dental professionals. A high proportion of SSc patients report difficulty accessing a dentist with knowledge of the disease and there is recognition amongst dentists that this could impact negatively on patient care. This review shall describe the clinical features and burden of orofacial manifestations of SSc and the management of such problems. The case is made for greater collaborative working between rheumatologists and dental professionals with an interest in SSc in both the research and clinical setting.

  4. Clinical manifestations of synovial cysts.

    PubMed

    Burt, T B; MacCarter, D K; Gelman, M I; Samuelson, C O

    1980-08-01

    Although synovial cysts are most commonly associated with rheumatoid arthritis and osteoarthritis, they may occur in many other conditions. The clinical manifestations of these cysts are numerous and may result from pressure, dissection or acute rupture. Vascular phenomena occur when popliteal cysts compress vessels, and result in venous stasis with subsequent lower extremity edema or thrombophlebitis. Rarely, popliteal cysts may cause arterial compromise with intermittent claudication. Neurological sequelae include pain, paresthesia, sensory loss, and muscle weakness or atrophy. When synovial cysts occur as mass lesions they may mimic popliteal aneurysms or hematomas, adenopathy, tumors or even inguinal hernias. Cutaneous joint fistulas, septic arthritis or osteomyelitis, and spinal cord and bladder compression are examples of other infrequent complications. Awareness of the heterogeneous manifestations of synovial cysts may enable clinicians to avoid unnecessary diagnostic studies and delay in appropriate management. Arthrography remains the definitive diagnostic procedure of choice, although ultrasound testing may be useful.

  5. Management of Musculoskeletal Manifestations in Inflammatory Bowel Disease

    PubMed Central

    Sheth, Tejas; Pitchumoni, C. S.; Das, Kiron M.

    2015-01-01

    Musculoskeletal manifestations are the most common extraintestinal manifestations in inflammatory bowel diseases. Some appendicular manifestations are independent of gut inflammation and are treated with standard anti-inflammatory strategies. On the other hand, axial involvement is linked to gut inflammatory activity; hence, there is a considerable amount of treatment overlap. Biological therapies have revolutionized management of inflammatory bowel diseases as well as of associated articular manifestations. Newer mechanisms driving gut associated arthropathy have surfaced in the past decade and have enhanced our interests in novel treatment targets. Introduction of biosimilar molecules is expected in the US market in the near future and will provide an opportunity for considerable cost savings on healthcare. A multidisciplinary approach involving a gastroenterologist, rheumatologist, and physical therapist is ideal for these patients. PMID:26170832

  6. Rheumatic manifestations of diabetes mellitus.

    PubMed

    Lebiedz-Odrobina, Dorota; Kay, Jonathan

    2010-11-01

    DM is associated with various musculoskeletal manifestations. The strength of this relationship varies among the various musculoskeletal disorders; the associations are based mostly on epidemiologic data. For most of these conditions, definitive pathophysiologic correlates are lacking.Hand and shoulder disorders occur more frequently than other musculoskeletal manifestations of DM. Recognition of the association between DM and shoulder adhesive capsulitis, DD, and stenosing flexor tenosynovitis facilitates their correct diagnosis in the setting of DM and prompt initiation of appropriate treatment, which may include optimizing glycemic control. Conversely, awareness and identification of the characteristic musculoskeletal manifestations of DM may facilitate earlier diagnosis of DM and initiation of glucose-lowering therapy to retard the development of diabetic complications.Much less has been published about the musculoskeletal complications of DM than about its micro- and macrovascular complications. Prospective case-control cohort studies are needed to establish the true prevalence of musculoskeletal complications of DM and the metabolic syndrome, especially in this era of tighter glycemic control.The potential relationship between DM and the development of OA needs to be clarified in large, prospective, case-control cohort studies. The effect on musculoskeletal manifestations of various therapeutic regimens to manage DM should be studied prospectively. Treatment regimens for some musculoskeletal conditions associated with DM, such as DISH, should be studied in larger prospective, randomized,controlled clinical trials.At the molecular level, further studies are warranted to clarify the potential contribution of AGEs and adipokines to the development of OA and diabetic musculoskeletal syndromes, such as shoulder adhesive capsulitis, DD, stenosing flexor tenosynovitis, and LJM. Identification of such molecular targets for therapy would promote the development of

  7. Articular Manifestations of Systemic Diseases

    PubMed Central

    Bensen, W. G.

    1983-01-01

    Many systemic diseases present with articular manifestations. An understanding of the clinical, laboratory and radiological features of these diseases can lead to early diagnosis and appropriate therapy. This article describes the articular presentation and management of four generalized disorders: idiopathic hemachromatosis; sarcoidosis; hepatitis-B virus-induced arthritis, and polymyositis-dermatomyositis induced arthritis. ImagesFig. 2Fig. 3Fig. 4 PMID:21283470

  8. Systemic diseases with cutaneous manifestations.

    PubMed

    Merchant, S R; Taboada, J

    1995-07-01

    The purpose of this article is to briefly discuss the following cutaneous manifestations of selected systemic diseases: poxvirus; feline leukemia virus (FeLV); feline immunodeficiency virus (FIV); herpesvirus; calcivirus; pseudorabies; plague; tularemia; toxoplasmosis; leishmania; hypothyroidism; hyperthyroidism; hyperadrenocorticism; diabetes mellitus; acromegaly; thallium poisoning; pancreatic disease; hypereosinophilic syndrome; mucopolysaccharidosis; and pansteatitis. Recognition of these cutaneous signs may help alert the clinician to the possibility of an internal disorder so that the appropriate diagnostic tests can be considered.

  9. Monogenic autoinflammatory diseases: concept and clinical manifestations.

    PubMed

    Almeida de Jesus, Adriana; Goldbach-Mansky, Raphaela

    2013-06-01

    The objective of this review is to describe the clinical manifestations of the growing spectrum of monogenic autoinflammatory diseases including recently described syndromes. The autoinflammatory diseases can be grouped based on clinical findings: 1. the three classic hereditary "periodic fever syndromes", familial Mediterranean Fever (FMF); TNF receptor associated periodic syndrome (TRAPS); and mevalonate kinase deficiency/hyperimmunoglobulinemia D and periodic fever syndrome (HIDS); 2. the cryopyrin associated periodic syndromes (CAPS), comprising familial cold autoinflammatory syndrome (FCAS), Muckle-Wells syndrome (MWS) and neonatal-onset multisystem inflammatory disease (NOMID) or CINCA, and; 3. pediatric granulomatous arthritis (PGA); 4. disorders presenting with skin pustules, including deficiency of interleukin 1 receptor antagonist (DIRA); Majeed syndrome; pyogenic arthritis, pyoderma gangrenosum and acne (PAPA) syndrome; deficiency of interleukin 36 receptor antagonist (DITRA); CARD14 mediated psoriasis (CAMPS), and early-onset inflammatory bowel diseases (EO-IBD); 5. inflammatory disorders caused by mutations in proteasome components, the proteasome associated autoinflammatory syndromes (PRAAS) and 6. very rare conditions presenting with autoinflammation and immunodeficiency.

  10. Clinical manifestations of parainfluenza infection in children.

    PubMed

    Yang, Tsung-Yen; Lu, Chun-Yi; Kao, Chuan-Liang; Chen, Rong-Tsung; Ho, Yu-Huai; Yang, Shun-Cheng; Lee, Ping-Ing; Chen, Jong-Min; Lee, Chin-Yun; Huang, Li-Min

    2003-12-01

    Parainfluenza viruses are major pathogens causing respiratory illness, manifesting from mild upper respiratory tract infection to bronchiolitis and pneumonia. This retrospective study aimed at providing clinical and epidemiologic data addressing the parainfluenza virus infection in Taiwan. A total of 39 patients were enrolled in this study from March 1999 to December 2000. Infants and young children were the major susceptible population, with 87.2% of them younger than 3 years. No seasonal trend was noted for parainfluenza type 1 and type 2 infections. One clustering of parainfluenza virus type 3 infections occurred in late spring of 2000 based on collected results. Parainfluenza type 1 viral isolates accounted for all of the cases of croup. Most isolates of parainfluenza virus type 3 were associated with upper and/or lower respiratory tract infections. A substantial proportion of the patients had skin involvement; the identification of one case of possible parainfluenza virus-related erythema multiforme is particularly interesting, especially because the chances of a causal relation between viral infection and skin symptoms are formerly thought to be slight. The identification of parainfluenza virus in illnesses classically considered to be due to other viruses is intriguing and may have important implications in the management of childhood illness clinically.

  11. Classicism and Romanticism.

    ERIC Educational Resources Information Center

    Huddleston, Gregory H.

    1993-01-01

    Describes one teacher's methods for introducing to secondary English students the concepts of Classicism and Romanticism in relation to pictures of gardens, architecture, music, and literary works. Outlines how the unit leads to a writing assignment based on collected responses over time. (HB)

  12. Classical Mythology. Fourth Edition.

    ERIC Educational Resources Information Center

    Morford, Mark P. O.; Lenardon, Robert J.

    Designed for students with little or no background in classical literature, this book introduces the Greek and Roman myths of creation, myths of the gods, Greek sagas and local legends, and presents contemporary theories about the myths. Drawing on Homer, Hesiod, Pindar, Vergil, and others, the book provides many translations and paraphrases of…

  13. Renewing Literary Classics.

    ERIC Educational Resources Information Center

    Karolides, Nicholas J., Ed.

    1983-01-01

    The articles in this journal issue suggest techniques for classroom use of literature that has "withstood the test of time." The titles of the articles and their authors are as follows: (1) "The Storytelling Connection for the Classics" (Mary Ellen Martin); (2) "Elizabeth Bennet: A Liberated Woman" (Geneva Marking);…

  14. Careers in the Classics

    ERIC Educational Resources Information Center

    Lum, Lydia

    2005-01-01

    America's few Black classics professors have overcome contempt and criticism to contribute a unique perspective to the study of the ancient world. Dr. Patrice Rankine, an associate professor from Purdue University, has grown used to the irony. As one of the few Black classicists teaching at an American university, he has drawn plenty of skepticism…

  15. Classics in What Sense?

    ERIC Educational Resources Information Center

    Camic, Charles

    2008-01-01

    They seem the perfect bookends for the social psychologist's collection of "classics" of the field. Two volumes, nearly identical in shape and weight and exactly a century old in 2008--each professing to usher "social psychology" into the world as they both place the hybrid expression square in their titles but then proceed to stake out the field…

  16. Children's Classics. Fifth Edition.

    ERIC Educational Resources Information Center

    Jordan, Alice M.

    "Children's Classics," a 1947 article by Alice M. Jordan reprinted from "The Horn Book Magazine," examines the dynamics and appeal of some of the most famous books for young readers, including "Alice in Wonderland,""The Wind in the Willows,""Robinson Crusoe," and "Andersen's Fairy Tales." Paul Hein's annotated bibliography, a revision of Jordan's…

  17. Teaching Tomorrow's Classics.

    ERIC Educational Resources Information Center

    Tighe, Mary Ann; Avinger, Charles

    1994-01-01

    Describes young adult novels that may prove to be classics of the genre. Discusses "The "Chocolate War" by Robert Cormier, "The Outsiders" by S. E. Hinton, "The Witch of Blackbird Pond" by Elizabeth George Speare, and "On Fortune's Wheel" by Cynthia Voight. (HB)

  18. Getting into Classical Chinese

    ERIC Educational Resources Information Center

    Kent, George W.

    1976-01-01

    The world of classical Chinese is distant both in time and space from the world of the English-speaking American. The instructor must not, however, use a no-attention-to-meaning approach assuming some words are untranslateable or create confusion in discussing the nature of Chinese script. (CFM)

  19. Observations of classical cepheids

    NASA Technical Reports Server (NTRS)

    Pel, J. W.

    1980-01-01

    The observations of classical Cepheids are reviewed. The main progress that has been made is summarized and some of the problems yet to be solved are discussed. The problems include color excesses, calibration of color, duplicity, ultraviolet colors, temperature-color relations, mass discrepancies, and radius determination.

  20. Classical Demonstration of Polarization.

    ERIC Educational Resources Information Center

    Bauman, Robert P.; Moore, Dennis R.

    1980-01-01

    Presents a classical demonstration of polarization for high school students. The initial state of this model, which demonstrates the important concepts of the optical and quantum problems, was developed during the 1973 summer program on lecture demonstration at the U.S. Naval Academy. (HM)

  1. Classical galactosaemia revisited.

    PubMed

    Bosch, Annet M

    2006-08-01

    Classical galactosaemia (McKusick 230400) is an: autosomal recessive disorder of galactose metabolism, caused by a deficiency of the enzyme galactose-1-phosphate uridyltransferase (GALT; EC 2.7.712). Most patients present in the neonatal period, after ingestion of galactose, with jaundice, hepatosplenomegaly, hepatocellular insufficiency, food intolerance, hypoglycaemia, renal tubular dysfunction, muscle hypotonia, sepsis and cataract. The gold standard for diagnosis of classical galactosaemia is measurement of GALT activity in erythrocytes. Gas-chromatographic determination of urinary sugars and sugar alcohols demonstrates elevated concentrations of galactose and galactitol. The only therapy for patients with classical galactosaemia is a galactose-restricted diet, and initially all galactose must be removed from the diet as soon as the diagnosis is suspected. After the neonatal period, a lactose-free diet is advised in most countries, without restriction of galactose-containing fruit and vegetables. In spite of the strict diet, long-term complications such as retarded mental development, verbal dyspraxia, motor abnormalities and hypergonadotrophic hypogonadism are frequently seen in patients with classical galactosaemia. It has been suggested that these complications may result from endogenous galactose synthesis or from abnormal galactosylation. Novel therapeutic strategies, aiming at the prevention of galactose 1-phosphate production, should be developed. In the meantime, the follow-up protocol for patients with GALT deficiency should focus on early detection, evaluation and, if possible, early intervention in problems of motor, speech and cognitive development.

  2. Driven topological systems in the classical limit

    NASA Astrophysics Data System (ADS)

    Duncan, Callum W.; Öhberg, Patrik; Valiente, Manuel

    2017-03-01

    Periodically driven quantum systems can exhibit topologically nontrivial behavior, even when their quasienergy bands have zero Chern numbers. Much work has been conducted on noninteracting quantum-mechanical models where this kind of behavior is present. However, the inclusion of interactions in out-of-equilibrium quantum systems can prove to be quite challenging. On the other hand, the classical counterpart of hard-core interactions can be simulated efficiently via constrained random walks. The noninteracting model, proposed by Rudner et al. [Phys. Rev. X 3, 031005 (2013), 10.1103/PhysRevX.3.031005], has a special point for which the system is equivalent to a classical random walk. We consider the classical counterpart of this model, which is exact at a special point even when hard-core interactions are present, and show how these quantitatively affect the edge currents in a strip geometry. We find that the interacting classical system is well described by a mean-field theory. Using this we simulate the dynamics of the classical system, which show that the interactions play the role of Markovian, or time-dependent disorder. By comparing the evolution of classical and quantum edge currents in small lattices, we find regimes where the classical limit considered gives good insight into the quantum problem.

  3. Cardiac tamponade presenting as early manifestation in dengue fever.

    PubMed

    Bendwal, Suresh; Malviya, Kavita; Jatav, O P; Malviya, Kapil

    2014-03-01

    Dengue fever (DF) is an outbreak prone viral disease transmitted by aedes mosquitoes. It is often associated with evidence of plasma leakage due to increased vascular permeability manifested by pleural effusion, ascites, hypoproteinaemia and pericardial effusion. Cases of small pericardial effusion have been reported in association with dengue fever, largely with dengue haemorrhagic fever (DHF) during epidemic outbreaks. Dengue may rarely present with cardiac tamponade as early manifestation and urgent pericardiocentesis is life saving. A 34 year old male presented with low grade fever, headache, myalgia and breathlessness. Echocardiography revealed large pericardial effusion with right ventricular diagnostic collapse requiring urgent drainage. Subsequently patient improved. Dengue serology (both IgM and IgG) was reported as markedly elevated supporting a diagnosis of classic dengue fever.

  4. Clinical manifestation of mitochondrial diseases.

    PubMed

    Magner, Martin; Kolářová, Hana; Honzik, Tomáš; Švandová, Ivana; Zeman, Jiří

    2015-01-01

    Mitochondrial disorders (MD) represent a clinically, biochemically and genetically heterogeneous group of diseases associated with dysfunction of the oxidative phosphorylation system and pyruvate dehydrogenase complex. Our aim was to illustrate the most common clinical presentation of MD on the example of selected diseases and syndromes. The minimal prevalence of MD is estimated as 1 to 5,000. MD may manifest at any age since birth until late-adulthood with acute manifestation or as a chronic progressive disease. Virtually any organ may be impaired, but the organs with the highest energetic demands are most frequently involved, including brain, muscle, heart and liver. Some MD may manifest as a characteristic cluster of clinical features (e.g. MELAS syndrome, Kearns-Sayre syndrome). Diagnostics includes detailed history, the comprehensive clinical examination, results of specialized examinations (especially cardiology, visual fundus examination, brain imaging, EMG), laboratory testing of body fluids (lactate, aminoacids, organic acids), and analysis of bioptic samples of muscle, skin, and liver, eventually. Normal lactate level in blood does not exclude the possibility of MD. Although the aimed molecular genetic analyses may be indicated in some of mitochondrial diseases, the methods of next generation sequencing come into focus. Examples of treatment are arginine supplementation in MELAS syndrome, ketogenic diet in pyruvate oxidation disorders or quinone analogs in patients with LHON. Conclusion: The clinical suspicion of a mitochondrial disorder is often delayed, or the disease remains undiagnosed. The correct diagnosis and adequate treatment can improve prognosis of the patient. Access to genetic counseling is also of great importance.

  5. Cutaneous manifestations of chikungunya fever.

    PubMed

    Seetharam, K A; Sridevi, K; Vidyasagar, P

    2012-01-01

    Chikungunya fever, a re-emerging RNA viral infection produces different cutaneous manifestations in children compared to adults. 52 children with chikungunya fever, confirmed by positive IgM antibody test were seen during 2009-2010. Pigmentary lesions were common (27/52) followed by vesiculobullous lesions (16/52) and maculopapular lesions (14/52). Vesiculobullous lesions were most common in infants, although rarely reported in adults. Psoriasis was exacerbated in 4 children resulting in more severe forms. In 2 children, guttate psoriasis was observed for the first time.

  6. Cutaneous manifestation of gastrointestinal disease

    PubMed Central

    Kerstetter, Justin

    2016-01-01

    The gastrointestinal (GI) and cutaneous systems are closely linked in origin. Skin manifestations are frequently seen as a part of different GI syndromes. Gastroenterologists play an important role in recognizing the symptoms, patient workup and arriving at appropriate diagnoses, often in consultation with dermatologists. This review discusses the diseases with both cutaneous and intestinal involvement. Hereditary polyposis GI cancers, hereditary nonpolyposis colorectal cancers (CRCs), hamartomatous disorders, and inflammatory bowel disease (IBD) are reviewed with emphasis on the genetic basis, diagnostic, histologic findings, screening modalities, and therapeutic options. PMID:27034812

  7. Cutaneous manifestations of breast cancer.

    PubMed

    Tan, Antoinette R

    2016-06-01

    Breast cancer may present with cutaneous symptoms. The skin manifestations of breast cancer are varied. Some of the more common clinical presentations of metastatic cutaneous lesions from breast cancer will be described. Paraneoplastic cutaneous dermatoses have been reported as markers of breast malignancy and include erythema gyratum repens, acquired ichthyosis, dermatomyositis, multicentric reticulohistiocytosis, and hypertrichosis lanuginosa acquisita. Mammary Paget's disease, often associated with an underlying breast cancer, and Cowden syndrome, which has an increased risk of breast malignancy, each have specific dermatologic findings. Recognition of these distinct cutaneous signs is important in the investigation of either newly diagnosed or recurrent breast cancer.

  8. Un-renormalized classical electromagnetism

    SciTech Connect

    Ibison, Michael . E-mail: ibison@earthtech.org

    2006-02-15

    This paper follows in the tradition of direct-action versions of electromagnetism having the aim of avoiding a balance of infinities wherein a mechanical mass offsets an infinite electromagnetic mass so as to arrive at a finite observed value. However, the direct-action approach ultimately failed in that respect because its initial exclusion of self-action was later found to be untenable in the relativistic domain. Pursing the same end, this paper examines instead a version of electromagnetism wherein mechanical action is excluded and self-action is retained. It is shown that the resulting theory is effectively interacting due to the presence of infinite forces. A vehicle for the investigation is a pair of classical point charges in a positronium-like arrangement for which the orbits are found to be self-sustaining and naturally quantized.

  9. On the Classical Schrödinger Equation

    NASA Astrophysics Data System (ADS)

    Benseny, Albert; Tena, David; Oriols, Xavier

    2016-10-01

    In this paper, the classical Schrödinger equation (CSE), which allows the study of classical dynamics in terms of wave functions, is analyzed theoretically and numerically. First, departing from classical (Newtonian) mechanics, and assuming an additional single-valued condition for the Hamilton’s principal function, the CSE is obtained. This additional assumption implies inherent non-classical features on the description of the dynamics obtained from the CSE: the trajectories do not cross in the configuration space. Second, departing from Bohmian mechanics and invoking the quantum-to-classical transition, the CSE is obtained in a natural way for the center of mass of a quantum system with a large number of identical particles. This quantum development imposes the condition of dealing with a narrow wave packet, which implicitly avoids the non-classical features mentioned above. We illustrate all the above points with numerical simulations of the classical and quantum Schrödinger equations for different systems.

  10. Neonatal erythroderma as a first manifestation of Menkes disease.

    PubMed

    Galve, Javier; Vicente, Asunción; González-Enseñat, María Antonia; Pérez-Dueñas, Belén; Cusí, Victoria; Møller, Lisbeth Birk; Julià, Marc; Domínguez, Anna; Ferrando, Juan

    2012-07-01

    Menkes disease is an X-linked recessive lethal multisystemic disorder of copper metabolism. Progressive neurodegeneration, connective tissue disturbances, and peculiar kinky hair are the main manifestations. The low serum copper and ceruloplasmin suggests the diagnosis, which is confirmed by mutation analysis of the ATP7A gene. We report an exceptional presentation of classic Menkes disease with neonatal erythroderma. Genetic study revealed a deletion in exons 8 to 12 in the ATP7A gene. This study could allow pediatricians and pediatric dermatologists to diagnose the disorder as early as possible to establish prompt treatment with parenteral copper-histidine supplementation to improve prognosis.

  11. Nonequilibrium statistical mechanics of open classical systems

    NASA Astrophysics Data System (ADS)

    Rey-Bellet, Luc

    2006-03-01

    We describe the ergodic and thermodynamical properties of chains of anharmonic oscillators coupled, at the boundaries, to heat reservoirs at positive and different temperatures. We discuss existence and uniqueness of stationary states, rate of convergence to stationarity, heat flows and entropy production, Kubo formula and Gallavotti-Cohen fluctuation theorem.

  12. Rotating Space Elevators: Classical and Statistical Mechanics

    NASA Astrophysics Data System (ADS)

    Knudsen, Steven

    We investigate a novel and unique dynamical system, the Rotating Space Elevator (RSE). The RSE is a multiply rotating system of strings reaching beyond the Earth geo-synchronous satellite orbit. Objects sliding along the RSE string ("climbers") do not require internal engines or propulsion to be transported far away from the Earth's surface. The RSE thus solves a major problem in the space elevator technology which is how to supply the energy to the climbers moving along the string. The RSE is a double rotating floppy string. The RSE can be made in various shapes that are stabilized by an approximate equilibrium between the gravitational and inertial forces acting in the double rotating frame. The RSE exhibits a variety of interesting dynamical phenomena studied in this thesis.

  13. The symplectic group and classical mechanics.

    PubMed

    Dragt, Alex J

    2005-06-01

    The symplectic group is the underlying symmetry group for Hamiltonian dynamics. Yet relatively little is commonly known about its properties including its Lie structure and representations. This paper describes and summarizes some of these properties; and, as a first application of symplectic group theory, provides a symplectic classification of all first-order differential equations in an even number of variables.

  14. Factors Influencing Learning of Classical Mechanics.

    ERIC Educational Resources Information Center

    Champagne, Audrey B.; And Others

    Beginning college physics students' misconceptions about moving objects, their mathematics skills, and formal reasoning ability, are all believed to be related to their achievement in physics. It is hypothesized that students whose knowledge structures include misconceptions that are in conflict with concepts in the lectures and text will have…

  15. [Respiratory manifestations of Marfan's syndrome].

    PubMed

    Neuville, M; Jondeau, G; Crestani, B; Taillé, C

    2015-02-01

    Marfan's syndrome is a rare genetic disorder caused by a mutation of the gene FBN1, coding for the protein fibrillin-1. Cardiovascular, musculoskeletal and ophthalmic manifestations are the most commonly observed, but minor diagnostic criteria also include pulmonary manifestations. Pneumothorax, frequently relapsing, affects 5 to 11% of patients. Rib cage abnormalities (pectus excavatum or pectus carinatum) and apical blebs may contribute to their occurrence. Treatment does not require any specific procedure but there is an increased risk of recurrence. Pectus excavatum affects up to 60% of the patients, without any functional impairment in most cases. Surgery may be required (using the Nuss procedure) in case of cardiovascular or psychological symptoms. Marfan's syndrome is frequently associated with obstructive sleep apnoea, which may itself contribute to aortic dilatation. Some studies suggest a potential role of craniofacial abnormalities in the pathogenesis of sleep apnea in these patients. Pulmonologists should consider Marfan's syndrome when treating patients for recurrent spontaneous pneumothorax or rib cage abnormalities, since early detection of cardiac abnormalities improves the prognosis significantly.

  16. Coronal manifestations of preflare activity

    NASA Technical Reports Server (NTRS)

    Schmahl, E. J.; Webb, D. F.; Woodgate, B.; Waggett, P.; Bentley, R.; Hurford, G.; Schadee, A.; Schrijver, J.; Harrison, R.; Martens, P.

    1986-01-01

    A variety of coronal manifestations of precursors or preheating for flares are discussed. Researchers found that almost everyone with a telescope sees something before flares. Whether an all-encompassing scenario will ever be developed is not at all clear at present. The clearest example of preflare activity appears to be activated filaments and their manifestations, which presumably are signatures of a changing magnetic field. But researchers have seen two similar eruptions, one without any evidence of emerging flux (Kundu et al., 1985) and the other with colliding poles (Simon et al., 1984). While the reconnection of flux is generally agreed to be required to energize a flare, the emergence of flux from below (at least on short timescales and in compact regions) does not appear to be a necessary condition. In some cases the cancelling of magnetic flux (Martin, 1984) by horizontal motions instead may provide the trigger (Priest, 1985) Researchers found similarities and some differences between these and previous observations. The similarities, besides the frequent involvement of filaments, include compact, multiple precursors which can occur both at and near (not at) the flare site, and the association between coronal sources and activity lower in the atmosphere (i.e., transition zone and chromosphere).

  17. The Statistical Interpretation of Classical Thermodynamic Heating and Expansion Processes

    ERIC Educational Resources Information Center

    Cartier, Stephen F.

    2011-01-01

    A statistical model has been developed and applied to interpret thermodynamic processes typically presented from the macroscopic, classical perspective. Through this model, students learn and apply the concepts of statistical mechanics, quantum mechanics, and classical thermodynamics in the analysis of the (i) constant volume heating, (ii)…

  18. 40 CFR 761.210 - Manifest discrepancies.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Section 761.210 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES... PROHIBITIONS PCB Waste Disposal Records and Reports § 761.210 Manifest discrepancies. (a) Manifest discrepancies are differences between the quantity or type of PCB waste designated on the manifest or...

  19. 40 CFR 761.215 - Manifest discrepancies.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Section 761.215 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES... PROHIBITIONS PCB Waste Disposal Records and Reports § 761.215 Manifest discrepancies. (a) Manifest... quantity or type of PCB waste designated on the manifest or shipping paper, and the quantity and type...

  20. 40 CFR 761.210 - Manifest discrepancies.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Section 761.210 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES... PROHIBITIONS PCB Waste Disposal Records and Reports § 761.210 Manifest discrepancies. (a) Manifest discrepancies are differences between the quantity or type of PCB waste designated on the manifest or...

  1. 40 CFR 761.210 - Manifest discrepancies.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Section 761.210 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) TOXIC SUBSTANCES... PROHIBITIONS PCB Waste Disposal Records and Reports § 761.210 Manifest discrepancies. (a) Manifest discrepancies are differences between the quantity or type of PCB waste designated on the manifest or...

  2. Extraintestinal Manifestations of Inflammatory Bowel Disease

    PubMed Central

    Burakoff, Robert

    2011-01-01

    Extraintestinal manifestations of inflammatory bowel disease are prevalent in both ulcerative colitis and Crohn's disease. The most common manifestations involve the musculoskeletal and dermatologic systems. Other manifestations involve the hepatopan-creatobiliary system (eg, primary sclerosing cholangitis) as well as the ocular, renal, and pulmonary systems. A multidisciplinary team approach is often needed for effective management, and emergency situations require prompt evaluation. PMID:21857821

  3. 14 CFR 121.665 - Load manifest.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Load manifest. 121.665 Section 121.665..., FLAG, AND SUPPLEMENTAL OPERATIONS Dispatching and Flight Release Rules § 121.665 Load manifest. Each certificate holder is responsible for the preparation and accuracy of a load manifest form before each...

  4. 14 CFR 121.665 - Load manifest.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Load manifest. 121.665 Section 121.665..., FLAG, AND SUPPLEMENTAL OPERATIONS Dispatching and Flight Release Rules § 121.665 Load manifest. Each certificate holder is responsible for the preparation and accuracy of a load manifest form before each...

  5. 14 CFR 121.665 - Load manifest.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Load manifest. 121.665 Section 121.665..., FLAG, AND SUPPLEMENTAL OPERATIONS Dispatching and Flight Release Rules § 121.665 Load manifest. Each certificate holder is responsible for the preparation and accuracy of a load manifest form before each...

  6. 14 CFR 121.665 - Load manifest.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Load manifest. 121.665 Section 121.665..., FLAG, AND SUPPLEMENTAL OPERATIONS Dispatching and Flight Release Rules § 121.665 Load manifest. Each certificate holder is responsible for the preparation and accuracy of a load manifest form before each...

  7. 14 CFR 121.665 - Load manifest.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Load manifest. 121.665 Section 121.665..., FLAG, AND SUPPLEMENTAL OPERATIONS Dispatching and Flight Release Rules § 121.665 Load manifest. Each certificate holder is responsible for the preparation and accuracy of a load manifest form before each...

  8. The classic project

    NASA Astrophysics Data System (ADS)

    Iselin, F. Christoph

    1997-02-01

    Exchange of data and algorithms among accelerator physics programs is difficult because of unnecessary differences in input formats and internal data structures. To alleviate these problems a C++ class library called CLASSIC (Class Library for Accelerator System Simulation and Control) is being developed with the goal to provide standard building blocks for computer programs used in accelerator design. It includes modules for building accelerator lattice structures in computer memory using a standard input language, a graphical user interface, or a programmed algorithm. It also provides simulation algorithms. These can easily be replaced by modules which communicate with the control system of the accelerator. Exchange of both data and algorithm between different programs using the CLASSIC library should present no difficulty.

  9. Classical swine fever.

    PubMed

    Moennig, V; Becher, P; Beer, M

    2013-01-01

    Classical swine fever is a serious and economically important transboundary disease threatening pig production globally. The infection may occur in backyard pigs, feral pig populations and domestic pigs. Whereas there are proven control strategies for the latter pig population, control in backyard pigs with poor biosecurity settings or in wild boar populations of high density still poses a problem in some parts of the world. Laboratory diagnostic methods, efficacious vaccines and contingency plans are in place in most industrialised countries. So far modified live vaccines (MLV) are still the first choice for rapid and reliable immune protection. Since antibodies elicited by conventional MLV cannot be distinguished from antibodies after natural infection, considerable efforts are put into the development of a live marker vaccine accompanied by a serological test. Nevertheless, some remaining gaps with respect to the diagnosis of and vaccination against classical swine fever have been identified.

  10. Classical Vs. Superfluid Turbulence

    NASA Astrophysics Data System (ADS)

    Roche, P.-E.

    2008-11-01

    Thanks to a zero-viscosity, superfluids offer a unique testing ground for hydrodynamic models, in particular for turbulence ones. In Kolmogorov's turbulence model, viscosity is well known to damp the kinetic energy of the smallest eddies, and thus to introduce a cut-off at one end of the turbulent cascade. Significant differences between this ``classical'' turbulence and the turbulence of a superfluid are therefore expected, but --surprisingly- most experiments rather evidenced strong similarities. We will give an overview of a set of experiments designed to compare in details the classical versus superfluid turbulences, up to a record mass flow of superfluid (700g/s of He @ 1.6K). Then, we will focus on some unexpected vorticity measurements, which can be interpreted assuming that the superfluid vortices are passively advected by the largest scales of the flow, in contrast with the ``classical'' turbulence counterpart. Numerical simulations -based on regular DNS- will be presented to complete this interpretation. In collaboration with C. Barenghi, University of Newcastle; B. Castaing and E. Levèque, ENSL, Lyon; S. David, IEF, CNRS, Orsay; B. Rousset, SBT/CEA, Grenoble; and P. Tabeling, H. Willaime MMN, ESPCI, Paris.

  11. Extraintestinal manifestations in inflammatory bowel disease

    PubMed Central

    Danese, Silvio; Semeraro, Stefano; Papa, Alfredo; Roberto, Italia; Scaldaferri, Franco; Fedeli, Giuseppe; Gasbarrini, Giovanni; Gasbarrini, Antonio

    2005-01-01

    Inflammatory bowel diseases (IBD) can be really considered to be systemic diseases since they are often associated with extraintestinal manifestations, complications, and other autoimmune disorders. Indeed, physicians who care for patients with ulcerative colitis and Crohn’s disease, the two major forms of IBD, face a new clinical challenge every day, worsened by the very frequent rate of extraintestinal complications. The goal of this review is to provide an overview and an update on the extraintestinal complications occurring in IBD. Indeed, this paper highlights how virtually almost every organ system can be involved, principally eyes, skin, joints, kidneys, liver and biliary tracts, and vasculature (or vascular system) are the most common sites of systemic IBD and their involvement is dependent on different mechanisms. PMID:16437620

  12. Pulmonary manifestations of inflammatory bowel disease

    PubMed Central

    Majewski, Sebastian

    2015-01-01

    Bronchopulmonary signs and symptoms are examples of variable extraintestinal manifestations of the inflammatory bowel diseases (IBD). These complications of Crohn's disease (CD) and ulcerative colitis (UC) seem to be underrecognized by both pulmonary physicians and gastroenterologists. The objective of the present review was to gather and summarize information on this particular matter, on the basis of available up-to-date literature. Tracheobronchial involvement is the most prevalent respiratory presentation, whereas IBD-related interstitial lung disease is less frequent. Latent and asymptomatic pulmonary involvement is not unusual. Differential diagnosis should always consider infections (mainly tuberculosis) and drug-induced lung pathology. The common link between intestinal disease and lung pathology is unknown, but many hypotheses have been proposed. It is speculated that environmental pollution, common immunological mechanisms and predisposing genetic factors may play a role. PMID:26788078

  13. Clinic manifestations in granulomatosis with polyangiitis.

    PubMed

    Greco, A; Marinelli, C; Fusconi, M; Macri, G F; Gallo, A; De Virgilio, A; Zambetti, G; de Vincentiis, M

    2016-06-01

    Granulomatosis with polyangiitis (GPA), formerly Wegener's granulomatosis (WG), is an uncommon immunologically mediated systemic small-vessel vasculitis that is pathologically characterised by an inflammatory reaction pattern (necrosis, granulomatous inflammation and vasculitis) that occurs in the upper and lower respiratory tracts and kidneys. Although the aetiology of GPA remains largely unknown, it is believed to be autoimmune in origin and triggered by environmental events on a background of genetic susceptibility.In Europe, the prevalence of GPA is five cases per 100,000 population, with greater incidence in Northern Europe. GPA can occur in all racial groups but predominantly affects Caucasians. Both sexes are affected equally. GPA affects a wide age range (age range, 8-99 years).Granulomatosis with polyangiitis is characterised by necrotising granulomatous lesions of the respiratory tract, vasculitis and glomerulonephritis. Classically, the acronym ELK is used to describe the clinical involvement of the ear, nose and throat (ENT); lungs; and kidneys. Because the upper respiratory tract is involved in 70-100% of cases of GPA, classic otorhinolaryngologic symptoms may be the first clinical manifestation of disease. The nasal cavity and the paranasal sinuses are the most common sites of involvement in the head and neck area (85-100%), whereas otological disease is found in approximately 35% (range, 19-61%) of cases.Diagnosis of GPA is achieved through clinical assessment, serological tests for anti-neutrophil cytoplasmic antibodies (ANCA) and histological analysis. The 10-year survival rate is estimated to be 40% when the kidneys are involved and 60-70% when there is no kidney involvement.The standard therapy for GPA is a combination of glucocorticoids and cyclophosphamide. In young patients, cyclophosphamide should be switched to azathioprine in the maintenance phase.A multidisciplinary approach, involving otorhinolaryngologists, oral and maxillofacial

  14. MUCOCUTANEOUS MANIFESTATIONS OF CHIKUNGUNYA FEVER

    PubMed Central

    Bandyopadhyay, Debabrata; Ghosh, Sudip Kumar

    2010-01-01

    Chikungunya fever (CF) is an arboviral acute febrile illness transmitted by the bite of infected Aedes mosquitoes. After a quiescence of more than three decades, CF has recently re-emerged as a major public health problem of global scale. CF is characterized by an acute onset of high fever associated with a severe disabling arthritis often accompanied by prominent mucocutaneous manifestations. The disease is usually self-limiting, but the joint symptoms and some of the cutaneous features may persist after the defervescence. A wide range of mucocutaneous changes has been described to occur in association with CF during the current epidemic. Besides a morbilliform erythema, hyperpigmentation, xerosis, excoriated papules, aphthous-like ulcers, vesiculobullous and lichenoid eruptions, and exacerbation of pre-existing or quiescent dermatoses had been observed frequently. These unusual features may help in the clinical differential diagnosis of acute viral exanthems mimicking CF. PMID:20418982

  15. Manifestations of Systemic Lupus Erythematosus

    PubMed Central

    COJOCARU, Manole; COJOCARU, Inimioara Mihaela; SILOSI, Isabela; VRABIE, Camelia Doina

    2011-01-01

    ABSTRACT Systemic lupus erythematosus (SLE) is a chronic, multifaceted autoimmune inflammatory disease that can affect any part of the body. SLE is a disease of unknown aetiology with a variety of presenting features and manifestations. Interest in the disease has been stimulated in recent years, and improved methods of diagnosis have resulted in a significant increase in the number of cases recognized. It is apparent that it can no longer be regarded as a rare disease. The majority of the pathology in SLE is related to deposits of immune complexes in various organs, which triggers complement and other mediators of inflammation. Symptoms vary from person to person, and may come and go, depend on what part of the body is affected, can be mild, moderate, or severe. Diagnosis can be difficult because lupus mimics many other diseases; it requires clinical and serologic criteria. PMID:22879850

  16. Cardiac manifestations in Behcet's disease

    PubMed Central

    Demirelli, Selami; Degirmenci, Husnu; Inci, Sinan; Arisoy, Arif

    2015-01-01

    Summary Behcet's disease (BD) is a chronic inflammatory disorder, with vasculitis underlying the pathophysiology of its multisystemic effects. Venous pathology and thrombotic complications are hallmarks of BD. However, it has been increasingly recognised that cardiac involvement and arterial complications are also important aspects of the course of the disease. Cardiac lesions include pericarditis, endocarditis, intracardiac thrombosis, myocardial infarction, endomyocardial fibrosis, and myocardial aneurysm. Treatment of cardiovascular involvement in BD is largely empirical, and is aimed towards suppressing the vasculitis. The most challenging aspect seems to be the treatment of arterial aneurysms and thromboses due to the associated risk of bleeding. When the prognosis of cardiac involvement in BD is not good, recovery can be achieved through oral anticoagulation, immunosuppressive therapy, and colchicine use. In this review, we summarise the cardiovascular involvement, different manifestations, and treatment of BD. PMID:25984424

  17. Oral manifestations in transplant patients

    PubMed Central

    Nappalli, Deepika; Lingappa, Ashok

    2015-01-01

    Organ transplantation is a widely undertaken procedure and has become an important alternative for the treatment of different end-stage organ diseases that previously had a poor prognosis. The field of organ transplant and hematopoietic stem cell transplant is developing rapidly. The increase in the number of transplant recipients also has an impact on oral and dental services. Most of the oral problems develop as a direct consequence of drug-induced immunosuppression or the procedure itself. These patients may present with oral complaints due to infections or mucosal lesions. Such lesions should be identified, diagnosed, and treated. New treatment strategies permit continuous adaptation of oral care regimens to the changing scope of oral complications. The aim of this review is to analyze those oral manifestations and to discuss the related literature. PMID:26005458

  18. Quantum Mechanics From the Cradle?

    ERIC Educational Resources Information Center

    Martin, John L.

    1974-01-01

    States that the major problem in learning quantum mechanics is often the student's ignorance of classical mechanics and that one conceptual hurdle in quantum mechanics is its statistical nature, in contrast to the determinism of classical mechanics. (MLH)

  19. Medical and rehabilitation issues in classical ballet.

    PubMed

    Stretanski, Michael F; Weber, G J

    2002-05-01

    Classical ballet is a demanding professional occupation, with participants who are often underserved in terms of accurate diagnosis and appropriate comprehensive medical care. The view that follows is designed to be as global and insightful as published to date. Specific rehabilitation considerations, dance mechanics, idiosyncratic differential diagnosis, and personality and equipment issues are discussed, and a rational view of dogma is presented.

  20. Maxwell and the classical wave particle dualism.

    PubMed

    Mendonça, J T

    2008-05-28

    Maxwell's equations are one of the greatest theoretical achievements in physics of all times. They have survived three successive theoretical revolutions, associated with the advent of relativity, quantum mechanics and modern quantum field theory. In particular, they provide the theoretical framework for the understanding of the classical wave particle dualism.

  1. Semi-classical Electrodynamics

    NASA Astrophysics Data System (ADS)

    Lestone, John

    2016-03-01

    Quantum electrodynamics is complex and its associated mathematics can appear overwhelming for those not trained in this field. We describe semi-classical approaches that can be used to obtain a more intuitive physical feel for several QED processes including electro-statics, Compton scattering, pair annihilation, the anomalous magnetic moment, and the Lamb shift, that could be taught easily to undergraduate students. Any physicist who brings their laptop to the talk will be able to build spread sheets in less than 10 minutes to calculate g/2 =1.001160 and a Lamb shift of 1057 MHz.

  2. Nonmonotonic quantum-to-classical transition in multiparticle interference

    PubMed Central

    Ra, Young-Sik; Tichy, Malte C.; Lim, Hyang-Tag; Kwon, Osung; Mintert, Florian; Buchleitner, Andreas; Kim, Yoon-Ho

    2013-01-01

    Quantum-mechanical wave–particle duality implies that probability distributions for granular detection events exhibit wave-like interference. On the single-particle level, this leads to self-interference—e.g., on transit across a double slit—for photons as well as for large, massive particles, provided that no which-way information is available to any observer, even in principle. When more than one particle enters the game, their specific many-particle quantum features are manifested in correlation functions, provided the particles cannot be distinguished. We are used to believe that interference fades away monotonically with increasing distinguishability—in accord with available experimental evidence on the single- and on the many-particle level. Here, we demonstrate experimentally and theoretically that such monotonicity of the quantum-to-classical transition is the exception rather than the rule whenever more than two particles interfere. As the distinguishability of the particles is continuously increased, different numbers of particles effectively interfere, which leads to interference signals that are, in general, nonmonotonic functions of the distinguishability of the particles. This observation opens perspectives for the experimental characterization of many-particle coherence and sheds light on decoherence processes in many-particle systems. PMID:23297196

  3. Skin gangrene as an extraintestinal manifestation of inflammatory bowel disease*

    PubMed Central

    Komatsu, Yumi Cristina; Capareli, Gabriela Cunha; Boin, Maria Fernanda Feitosa de Camargo; Lellis, Rute; de Freitas, Thaís Helena Proença; Simone, Karine

    2014-01-01

    Inflammatory bowel diseases can commonly present many cutaneous lesions which can contribute to the diagnosis of the disease or its activity. The most frequent cutaneous or mucocutaneous manifestations suggesting ulcerative rectocolitis activity are erythema nodosum (3-10%), pyoderma gangrenosum (5-12%) and aphthous stomatitis (4%). Other reactive skin manifestations related to immunological mechanisms associated with the inflammatory bowel disease are: Sweet's syndrome, arthritis-dermatitis syndrome associated with inflammatory bowel disease and leukocytoclastic vasculitis. We describe the case of a young man with diagnosis of ulcerative rectocolitis, which presented an extensive cutaneous gangrene secondary to microvascular thrombosis. The case represents a dermatologic rarity and should be recognized as a cutaneous manifestation related to the hypercoagulability state observed in the disease's activity. PMID:25387503

  4. Skin gangrene as an extraintestinal manifestation of inflammatory bowel disease.

    PubMed

    Komatsu, Yumi Cristina; Capareli, Gabriela Cunha; Boin, Maria Fernanda Feitosa de Camargo; Lellis, Rute; Freitas, Thaís Helena Proença de; Simone, Karine

    2014-01-01

    Inflammatory bowel diseases can commonly present many cutaneous lesions which can contribute to the diagnosis of the disease or its activity. The most frequent cutaneous or mucocutaneous manifestations suggesting ulcerative rectocolitis activity are erythema nodosum (3-10%), pyoderma gangrenosum (5-12%) and aphthous stomatitis (4%). Other reactive skin manifestations related to immunological mechanisms associated with the inflammatory bowel disease are: Sweet's syndrome, arthritis-dermatitis syndrome associated with inflammatory bowel disease and leukocytoclastic vasculitis. We describe the case of a young man with diagnosis of ulcerative rectocolitis, which presented an extensive cutaneous gangrene secondary to microvascular thrombosis. The case represents a dermatologic rarity and should be recognized as a cutaneous manifestation related to the hypercoagulability state observed in the disease's activity.

  5. Epidemiology of extra-articular manifestations in rheumatoid arthritis.

    PubMed

    Turesson, C; Jacobsson, L T H

    2004-01-01

    Extra-articular RA (ExRA) includes a wide variety of disease manifestations. Although rheumatologists in general are aware that such events are clinically important, the heterogeneity of available data, including discrepancies in case definitions, has complicated constructive discussions on this aspect of the RA disease phenotype. In recent years, there has been a growing recognition of the importance of co-morbidity in patients with RA. ExRA manifestations are not uncommon, explain excess mortality in RA and are predicted by smoking and autoantibodies. Further studies of the mechanisms underlying these associations are likely to be important in improving our understanding of the systemic nature of RA. This article discusses the methodological issues involved in the study of ExRA manifestations, presents suggested criteria that have been used in clinical studies, and reviews important surveys of the epidemiology of extra-articular RA.

  6. Fano Interference in Classical Oscillators

    ERIC Educational Resources Information Center

    Satpathy, S.; Roy, A.; Mohapatra, A.

    2012-01-01

    We seek to illustrate Fano interference in a classical coupled oscillator by using classical analogues of the atom-laser interaction. We present an analogy between the dressed state picture of coherent atom-laser interaction and a classical coupled oscillator. The Autler-Townes splitting due to the atom-laser interaction is analogous to the…

  7. Classical Trajectories and Quantum Spectra

    NASA Technical Reports Server (NTRS)

    Mielnik, Bogdan; Reyes, Marco A.

    1996-01-01

    A classical model of the Schrodinger's wave packet is considered. The problem of finding the energy levels corresponds to a classical manipulation game. It leads to an approximate but non-perturbative method of finding the eigenvalues, exploring the bifurcations of classical trajectories. The role of squeezing turns out decisive in the generation of the discrete spectra.

  8. [Myositis and the skin: cutaneous manifestations of dermatomyositis].

    PubMed

    Jinnin, Masatoshi

    2013-11-01

    Idiopathic inflammatory myopathies include dermatomyositis, polymyositis, and inclusion body myositis. Among them, cutaneous manifestations are observed most frequently in dermatomyositis. While dermatomyositis commonly affects the skin and muscles, it can also affect the lungs and other organs. Dermatomyositis presenting clinically and histopathologically with typical cutaneous lesions, but without myositis, is called amyopathic dermatomyositis. Given that the Bohan and Peter criteria cannot distinguish amyopathic dermatomyositis, understanding the characteristic skin manifestations may be essential for diagnosing this condition. The cutaneous manifestations of dermatomyositis are thought to be the result of the Koebner phenomenon, vasculopathy, or photosensitivity; manifestations include various eruptions, such as heliotrope rush, Gottron's sign, Gottron's papules, mechanic's hand, nail-fold bleeding, skin ulcer, vasculitis, flagellate erythema, V-sign, and Shawl sign. The presence of multiple types of eruptions can help diagnose the disease. Several skin diseases, including adult Still's disease, contact dermatitis, and sarcoidosis, can mimic the cutaneous manifestations of dermatomyositis. Skin biopsy is useful for differential diagnoses. Histopathologically, dermatomyositis of the skin is characterized by liquefaction degeneration, vacuolar degeneration, edema, and mucin deposition. Dermatologists, neurologists, and rheumatologists are responsible for the diagnosis and management of dermatomyositis, in cooperation with pulmonologists, pediatricians, and pathologists. This review aims to provide clinicians with recent findings regarding skin involvement in dermatomyositis.

  9. Vaccines for viral diseases with dermatologic manifestations.

    PubMed

    Brentjens, Mathijs H; Yeung-Yue, Kimberly A; Lee, Patricia C; Tyring, Stephen K

    2003-04-01

    Vaccines against infectious diseases have been available since the 1800s, when an immunization strategy against smallpox developed by Jenner gained wide acceptance. Until recently, the only vaccination strategies available involved the use of protein-based, whole killed, and attenuated live virus vaccines. These strategies have led to the development of effective vaccines against a variety of diseases with primary or prominent cutaneous manifestations. Effective and safe vaccines now used worldwide include those directed against measles and rubella (now commonly used together with a mumps vaccine as the trivalent MMR), chickenpox, and hepatitis B. The eradication of naturally occurring smallpox remains one of the greatest successes in the history of modern medicine, but stockpiles of live smallpox exist in the United States and Russia. Renewed interest in the smallpox vaccine reflects concerns about a possible bioterrorist threat using this virus. Yellow fever is a hemorrhagic virus endemic to tropical areas of South America and Africa. An effective vaccine for this virus has existed since 1937, and it is used widely in endemic areas of South America, and to a lesser extent in Africa. This vaccine is recommended once every 10 years for people who are traveling to endemic areas. Advances in immunology have led to a greater understanding of immune system function in viral diseases. Progress in genetics and molecular biology has allowed researchers to design vaccines with novel mechanisms of action (eg, DNA, vector, and VLP vaccines). Vaccines have also been designed to specifically target particular viral components, allowing for stimulation of various arms of the immune system as desired. Ongoing research shows promise in prophylactic and therapeutic vaccination for viral infections with cutaneous manifestations. Further studies are necessary before vaccines for HSV, HPV, and HIV become commercially available.

  10. Decoherence, chaos, the quantum and the classical

    SciTech Connect

    Zurek, W.H.; Paz, J.P.

    1994-04-01

    The key ideas of the environment-induced decoherence approach are reviewed. Application of decoherence to the transition from quantum to classical in open quantum systems with chaotic classical analogs is described. The arrow of time is, in this context, a result of the information loss to the correlations with the environment. The asymptotic rate of entropy production (which is reached quickly, on the dynamical timescale) is independent of the details of the coupling of the quantum system to the environment, and is set by the Lyapunov exponents. We also briefly outline the existential interpretation of quantum mechanics, justifying the slogan ``No information without representation.``

  11. Force fields for classical molecular dynamics.

    PubMed

    Monticelli, Luca; Tieleman, D Peter

    2013-01-01

    In this chapter we review the basic features and the principles underlying molecular mechanics force fields commonly used in molecular modeling of biological macromolecules. We start by summarizing the historical background and then describe classical pairwise additive potential energy functions. We introduce the problem of the calculation of nonbonded interactions, of particular importance for charged macromolecules. Different parameterization philosophies are then presented, followed by a section on force field validation. We conclude with a brief overview on future perspectives for the development of classical force fields.

  12. Cardiac manifestations of parasitic diseases.

    PubMed

    Nunes, Maria Carmo P; Guimarães Júnior, Milton Henriques; Diamantino, Adriana Costa; Gelape, Claudio Leo; Ferrari, Teresa Cristina Abreu

    2017-03-11

    The heart may be affected directly or indirectly by a variety of protozoa and helminths. This involvement may manifest in different ways, but the syndromes resulting from impairment of the myocardium and pericardium are the most frequent. The myocardium may be invaded by parasites that trigger local inflammatory response with subsequent myocarditis or cardiomyopathy, as occurs in Chagas disease, African trypanosomiasis, toxoplasmosis, trichinellosis and infection with free-living amoebae. In amoebiasis and echinococcosis, the pericardium is the structure most frequently involved with consequent pericardial effusion, acute pericarditis, cardiac tamponade or constrictive pericarditis. Chronic hypereosinophilia due to helminth infections, especially filarial infections, has been associated with the development of tropical endomyocardial fibrosis, a severe form of restrictive cardiomyopathy. Schistosomiasis-associated lung vasculature involvement may cause pulmonary hypertension (PH) and cor pulmonale Tropical pulmonary eosinophilia, which is characterised by progressive interstitial fibrosis and restrictive lung disease, may lead to PH and its consequences may occur in the course of filarial infections. Intracardiac rupture of an Echinococcus cyst can cause membrane or secondary cysts embolisation to the lungs or organs supplied by the systemic circulation. Although unusual causes of cardiac disease outside the endemic areas, heart involvement by parasites should be considered in the differential diagnosis especially of myocardial and/or pericardial diseases of unknown aetiology in both immunocompetent and immunocompromised individuals. In this review, we updated and summarised the current knowledge on the major heart diseases caused by protozoan and metazoan parasites, which either involve the heart directly or otherwise influence the heart adversely.

  13. Neurologic manifestations of Angelman syndrome.

    PubMed

    Thibert, Ronald L; Larson, Anna M; Hsieh, David T; Raby, Annabel R; Thiele, Elizabeth A

    2013-04-01

    Angelman syndrome is a neurogenetic disorder characterized by the loss or reduction of the ubiquitin-protein ligase E3A enzyme. Angelman syndrome results from a deletion or mutation of the maternally inherited 15q11.2-13.1 region, paternal uniparental disomy of chromosome 15, or an imprinting error. Epilepsy is common and may present with multiple seizure types, including nonconvulsive status epilepticus. Seizures are often intractable and typically require broad-spectrum antiepileptic medications. Dietary therapy has also proved successful in Angelman syndrome. Electroencephalographic patterns include notched δ and rhythmic θ activity and epileptiform discharges. Sleep disorders are also common, often characterized by abnormal sleep-wake cycles. Movement disorders are nearly universal in Angelman syndrome, most frequently presenting with ataxia and tremor. Neurocognitive impairment is always present to varying degrees, and expressive speech is typically severely affected. Individuals with Angelman syndrome often manifest psychiatric comorbidities including hyperactivity, anxiety, and challenging behaviors such as aggression and self-injury. We focus on a comprehensive whole-child approach to the diagnosis and long-term clinical care of individuals with Angelman syndrome.

  14. [Collagen diseases with gastrointestinal manifestations].

    PubMed

    Takahashi, Hiroki; Ohara, Mikiko; Imai, Kohzoh

    2004-06-01

    Collagen vascular diseases are known to present with a diverse array of gastrointestinal manifestations. These can be classified as: 1) gastrointestinal damage due to the collagen vascular disease itself; 2) adverse events caused by pharmacotherapies; or 3) gastrointestinal infections following immunosuppression due to corticosteroid (CS) administration. The first group includes lupus enteritis and protein-losing gastroenteropathy in systemic lupus erythematosus (SLE), reflux esophagitis, chronic intestinal pseudo-obstruction, and pneumatosis cystoids intestinalis in systemic sclerosis, amyloidosis in rheumatoid arthritis, bowel ulcer and bleeding in rheumatoid vasculitis and microscopic polyangiitis, and ileocecal ulcer in Behcet disease. In particular, colonic ulcers associated with SLE represent refractory lesions resistant to CS. Analysis of reported cases showing colonic lesions with SLE (22 cases in Japan) revealed that mean duration of SLE was 9.9 years and 77% of colonic lesions were observed in the rectum and sigmoid colon. Half of the patients developed intestinal perforation or penetration, and 6 of the 11 patients with perforation died. The second group includes lesions in the small and large intestine due to nonsteroidal anti-inflammatory drugs (NSAIDs) and CSs, in addition to peptic ulcers. As perforation in CS-treated patients displays relatively high incidence with poor prognosis, careful attention to such complications is needed. The third group includes candidal esophagitis and cytomegalovirus (CMV) enteritis. Prompt diagnosis is required to prevent colonic bleeding and perforation due to CMV.

  15. Rheumatological manifestations in diabetes mellitus.

    PubMed

    Del Rosso, Angela; Cerinic, Marco Matucci; De Giorgio, Francesca; Minari, Chiara; Rotella, Carlo Maria; Seghieri, Giuseppe

    2006-11-01

    Rheumatological manifestations of Diabetes Mellitus may be classified in: non articular, articular and bone conditions. Among non articular conditions, diabetic cheiroarthropathy, frequent in type I diabetes, the most important disorder related to limited joint mobility, results in stiff skin and joint contractures. Adhesive capsulitis of the shoulder, flexor tenosynovitis, and Duputryen's and Peyronie's diseases are also linked to limited joint mobility. Diffuse skeletal hyperostosis, due to calcification at entheses, is frequent and early, particularly in type 2 diabetes. Neuropathies cause some non articular conditions, mainly neuropathic arthritis, a destructive bone and joint condition more common in type I diabetes. Algodistrophy, shoulder-hand and entrapment syndromes are also frequent. Mononeuropathy causes diabetic amyotrophy, characterised by painless muscle weakness. Among muscle conditions, diabetic muscle infarction is a rare, sometimes severe, condition. Among articular conditions, osteoarthritis is frequent and early in diabetes, in which also chondrocalcinosis and gout occur. Rheumatoid arthritis (RA) and diabetes I have a common genetic background and the presence of diabetes gives to RA an unfavourable prognosis. Among bone conditions, osteopenia and osteoporosis may occur early in type 1 diabetes. Contrarily, in type 2 diabetes, bone mineral density is similar or, sometimes, higher than in non diabetic subjects, probably due to hyperinsulinemia.

  16. Skin manifestations in autoinflammatory syndromes.

    PubMed

    Braun-Falco, Markus; Ruzicka, Thomas

    2011-03-01

    Autoinflammatory diseases encompass a group of inflammatory diseases that are non-infectious, non-allergic, non-autoimmune and non-immunodeficient. The term was initially coined for a small group of familial periodic fever syndromes of which familial Mediterranean fever (FMF) is the most common and best known. Genetic and molecular analyses demonstrated for the majority of these diseases an impairment of inflammasomes to cause an increased activity of an interleukin-1-dependent inflammatory response. Over the last years an increasing number of either rare hereditary syndromes or acquired common diseases could be summarized under the designation of autoinflammatory disease, thus creating an emerging new rubric of inflammatory diseases. Many of them display cutaneous manifestations as both concomitant or more rarely main symptoms. To name some of them like erysipelas-like erythema in FMF; urticaria-like rashes in tumor necrosis factor receptor 1- or cryopyrin-associated periodic syndromes (TRAPS, CAPS), hyperimmunoglobulin D syndrome (HIDS) or Schnitzler syndrome; pyoderma gangrenosum and acne in PAPA syndrome; or behçetoid aphthous ulcerations in HIDS and PFAPA syndrome. Based on the new insights into pathogenesis one increasingly realizes the good response of these diseases to IL-1 antagonist therapies.

  17. Classical simulation of quantum energy flow in biomolecules.

    PubMed

    Stock, Gerhard

    2009-03-20

    Based on a comparison of classical and quantum-mechanical perturbation theory, the validity of classical nonequilibrium molecular dynamics simulations to describe vibrational energy redistribution in biomolecules is studied. Adopting a small model peptide in aqueous solution as an example, the theory correctly predicts quantum correction factors that need to be applied to the results of classical simulations in order to match the correct quantum results.

  18. The classical vacuum

    NASA Astrophysics Data System (ADS)

    Boyer, T. H.

    1985-08-01

    The history of vacuum concepts is reviewed, noting that no way is known to physically produce a true void. Even at absolute zero, a pattern of electromagnetic wave fluctuations are still present. The fluctuations are called zero-point radiation (ZPR). To be invariant to Lorentz transformation, ZPR has a spectral intensity proportional to the cube of each frequency. ZPR does not change in response to compression and produces a force between objects that is inversely proportional to the 4th power of the separation distance. The ZPR scale value has been measured to be one-half of the Planck constant, and is the measure of the energy of a harmonic oscillator, such as the electron, in a vacuum. Finally, since gravitational accelerations always occur in the physical space, a minimum thermal radiation can also be found for the vacuum, implying that a fixed relationship exists between thermal radiation and the classical vacuum.

  19. Supersymmetric classical cosmology

    SciTech Connect

    Escamilla-Rivera, Celia; Obregón, Octavio; Ureña-López, L. Arturo E-mail: octavio@fisica.ugto.mx

    2010-12-01

    In this work a supersymmetric cosmological model is analyzed in which we consider a general superfield action of a homogeneous scalar field supermultiplet interacting with the scale factor in a supersymmetric FRW model. There appear fermionic superpartners associated with both the scale factor and the scalar field, and classical equations of motion are obtained from the super-Wheeler-DeWitt equation through the usual WKB method. The resulting supersymmetric Einstein-Klein-Gordon equations contain extra radiation and stiff matter terms, and we study their solutions in flat space for different scalar field potentials. The solutions are compared to the standard case, in particular those corresponding to the exponential potential, and their implications for the dynamics of the early Universe are discussed in turn.

  20. Classical and quantum ghosts

    NASA Astrophysics Data System (ADS)

    Sbisà, Fulvio

    2015-01-01

    The aim of these notes is to provide a self-contained review of why it is generically a problem when a solution of a theory possesses ghost fields among the perturbation modes. We define what a ghost field is and we show that its presence is associated with a classical instability whenever the ghost field interacts with standard fields. We then show that the instability is more severe at quantum level, and that perturbative ghosts can exist only in low energy effective theories. However, if we do not consider very ad hoc choices, compatibility with observational constraints implies that low energy effective ghosts can exist only at the price of giving up Lorentz invariance or locality above the cut-off, in which case the cut-off has to be much lower that the energy scales we currently probe in particle colliders. We also comment on the possible role of extra degrees of freedom which break Lorentz invariance spontaneously.

  1. Ocular manifestations of HIV infection.

    PubMed Central

    Jabs, D A

    1995-01-01

    all stages of HIV infection. Fifty-six percent of the cases of ocular toxoplasmosis had simultaneous toxoplasmic cerebritis. Ocular toxoplasmosis responded to standard anti-microbial therapy. Varicella zoster virus retinitis, when manifested by the acute retinal necrosis (ARN) syndrome, responded to intravenous acyclovir therapy. Conversely, in a limited number of patients with the progressive outer retinal necrosis syndrome, the disease responded poorly to intravenous acyclovir therapy, but appeared to respond to combination foscarnet and acyclovir therapy. Neuro-ophthalmic lesions were present in 6% of the patients with AIDS. The most common cause of a neuro-ophthalmic lesion was cryptococcal meningitis, and 25% of the patients with cryptococcal meningitis developed a neuro-ophthalmic complication. CONCLUSIONS: Ocular manifestations are common in patients with AIDS. CMV retinitis represented a major vision-threatening problem in these patients. While available therapy was successful in initially controlling the retinitis, the phenomenon of relapse resulted in some degree of long-term visual loss. Preservation of the patient's visual acuity in at least one eye was generally successful. Other opportunistic ocular infections were substantially less common than CMV retinitis but require aggressive therapy. Images FIGURE 1 FIGURE 2 FIGURE 3 FIGURE 4 FIGURE 5 FIGURE 6 PMID:8719695

  2. Quantum and classical phases in optomechanics

    NASA Astrophysics Data System (ADS)

    Armata, Federico; Latmiral, Ludovico; Pikovski, Igor; Vanner, Michael R.; Brukner, Časlav; Kim, M. S.

    2016-06-01

    The control of quantum systems requires the ability to change and read-out the phase of a system. The noncommutativity of canonical conjugate operators can induce phases on quantum systems, which can be employed for implementing phase gates and for precision measurements. Here we study the phase acquired by a radiation field after its radiation pressure interaction with a mechanical oscillator, and compare the classical and quantum contributions. The classical description can reproduce the nonlinearity induced by the mechanical oscillator and the loss of correlations between mechanics and optical field at certain interaction times. Such features alone are therefore insufficient for probing the quantum nature of the interaction. Our results thus isolate genuine quantum contributions of the optomechanical interaction that could be probed in current experiments.

  3. Gastrointestinal manifestations in cystic fibrosis.

    PubMed

    Eggermont, E

    1996-08-01

    CFTR, or cystic fibrosis transmembrane conductance regulator, the gene product that is defective in cystic fibrosis, is present in the apical membrane of the epithelial cells from the stomach to the colon. In the foregut, the clinical manifestations are not directly related to the primary defect of the CFTR chloride channel. The most troublesome complaints and symptoms originate from the oesophagus as peptic oesophagitis or oesophageal varices. In the small intestinal wall, the clinical expression of CF depends largely on the decreased secretion of fluid and chloride ions, the increased permeability of the paracellular space between adjacent enterocytes and the sticky mucous cover over the enterocytes. As a rule, the brush border enzyme activities are normal and there is some enhanced active transport as shown for glucose and alanine. The results of continuous enteral feeding of CF patients clearly show that the small intestinal mucosa, in the daily situation, is not functioning at maximal capacity. Although CFTR expression in the colon is lower, the large intestine may be the site of several serious complications such as rectal prolapse, meconium ileus equivalent, intussusception, volvulus and silent appendicitis. In recent years colonic strictures, after the use of high-dose pancreatic enzymes, are being increasingly reported; the condition has recently been called CF fibrosing colonopathy. The CF gastrointestinal content itself differs mainly from the normal condition by the lower acidity in the foregut and the accretion of mucins and proteins, eventually resulting in intestinal obstruction, in the ileum and colon. Better understanding of the CF gastrointestinal phenotype may contribute to improvement of the overall wellbeing of these patients.

  4. [Neurologic manifestations of infectious endocarditis].

    PubMed

    Hannachi, N; Béard, T; Ben Ismail, M

    1991-01-01

    Thirty out of 287 patients (10.4%) admitted to hospital for infective endocarditis between December 1970 and January 1990 had neurological complications. Twenty-three patients had native valve infectious endocarditis and 7 had prosthetic valve endocarditis. The clinical features were characterized by the frequency of aortic valve involvement (23 out of 30) and other complications, especially cardiac failure (16 cases) and peripheral vascular manifestations (7 cases). The commonest organism was the staphylococcus (53% of identified organisms) but the number of negative blood cultures was high (50% of cases). The neurological complication was often the presenting symptom of the endocarditis (19 cases) but it occurred after bacteriological cure in 4 cases. The complications observed were cerebral ischemia (16 cases), cerebral haemorrhage (11 cases), coma (2 cases), and one peripheral neuropathy causing a Claude Bernard Horner syndrome. These complications presented with hemiplegia in 17 cases, a meningeal syndrome in 8 cases, a convulsion in 1 case, a Von Wallenberg syndrome in 1 case, and a Claude Bernard Horner syndrome in 1 case. Twelve patients had a transient or permanent neurological coma. Cerebral CT scan showed ischemic lesions in 7 cases and haemorrhagic lesions in 10 cases. Carotid angiography demonstrated mycotic aneurysms in 6 patients. Twelve patients died: the cause of death was neurological coma (7 cases), low cardiac output (4 cases) and haemorrhagic shock (1 case). Four patients underwent neurosurgery: 3 for clipping a mycotic aneurysm and 1 for drainage of an intracerebral haematoma. Poor prognostic factors were: coma, cardiac failure, cardiac valve prosthesis and, above all, the extent and multiplicity of the neurological lesions. The authors propose the following measures to improve the prognosis: early surgery in cases of large and/or mobile vegetations especially when the infecting organism is a staphylococcus and when a systemic embolism has

  5. Gender and its clinical manifestations.

    PubMed

    Olesker, Wendy

    2003-01-01

    Based on a study of five analytic cases (three reported here), and using a modern classical psychoanalytic perspective in which both biology and social forces are integrated, our study group on gender investigated why for some gender assumes a distorted and exaggerated role in the subjective sense of self. Clinical material was used because we wanted data allowing us to study patterns emerging from an exploration of patients' unconscious fantasies as they shed light on the psychological significance and function of gender. We found that in each case gender disturbances were never primary but secondary to difficulties in integration, cohesiveness, separateness, stability of solid sense of self and of the object, to depression and especially to problems with aggression and rivalry which had to be analyzed first. Conflicted gender gave rise to solutions that were literal and concrete. Not surprisingly, in each case mothers wished for a child of the opposite gender and treated gender expression in highly ambivalent ways. In terms of technique we learned that ways of coping with rejection, evolving paternal transferences which allowed for metabolisis of the maternal relationship, and ego building techniques had to take place before conflicts around gender could be analyzed productively.

  6. Classical transport in disordered systems

    NASA Astrophysics Data System (ADS)

    Papaioannou, Antonios

    This thesis reports on the manifestation of structural disorder on molecular transport and it consists of two parts. Part I discusses the relations between classical transport and the underlying structural complexity of the system. Both types of molecular diffusion, namely Gaussian and non- Gaussian are presented and the relevant time regimes are discussed. In addition the concept of structural universality is introduced and connected with the diffusion metrics. One of the most robust techniques for measuring molecular mean square displacements is magnetic resonance. This method requires encoding and subsequently reading out after an experimentally controlled time, a phase φ to the spins using magnetic field gradients. The main limitation for probing short diffusion lengths L(t) ˜ 1micro m with magnetic resonance is the requirement to encode and decode the phase φ in very short time intervals. Therefore, to probe such displacements a special probe was developed equipped with a gradient coil capable of delivering magnetic field gradients of approximately 90 G/cmA . The design of the probe is reported. Part I also includes a discussion of experiments of transport in two qualitatively different disordered phantoms and reports on a direct observation of universality in one-dimension. The results reveal the universal power law scaling of the diffusion coefficient at the long-time regime and illustrate the essence of structural universality by experimentally determining the structure correlation function of the phantoms. In addition, the scaling of the diffusive permeability of the phantoms with respect to the pore size is investigated. Additional work presented includes a detailed study of adsorption of methane gas in Vycor disordered glass. The techniques described in Part I of this thesis are widely used for measuring structural parameters of porous media, such as the surface-to-volume ratio or diffusive permeability. Part II of this thesis discusses the

  7. Nonlinear atom interferometer surpasses classical precision limit.

    PubMed

    Gross, C; Zibold, T; Nicklas, E; Estève, J; Oberthaler, M K

    2010-04-22

    Interference is fundamental to wave dynamics and quantum mechanics. The quantum wave properties of particles are exploited in metrology using atom interferometers, allowing for high-precision inertia measurements. Furthermore, the state-of-the-art time standard is based on an interferometric technique known as Ramsey spectroscopy. However, the precision of an interferometer is limited by classical statistics owing to the finite number of atoms used to deduce the quantity of interest. Here we show experimentally that the classical precision limit can be surpassed using nonlinear atom interferometry with a Bose-Einstein condensate. Controlled interactions between the atoms lead to non-classical entangled states within the interferometer; this represents an alternative approach to the use of non-classical input states. Extending quantum interferometry to the regime of large atom number, we find that phase sensitivity is enhanced by 15 per cent relative to that in an ideal classical measurement. Our nonlinear atomic beam splitter follows the 'one-axis-twisting' scheme and implements interaction control using a narrow Feshbach resonance. We perform noise tomography of the quantum state within the interferometer and detect coherent spin squeezing with a squeezing factor of -8.2 dB (refs 11-15). The results provide information on the many-particle quantum state, and imply the entanglement of 170 atoms.

  8. Unraveling Quantum Annealers using Classical Hardness.

    PubMed

    Martin-Mayor, Victor; Hen, Itay

    2015-10-20

    Recent advances in quantum technology have led to the development and manufacturing of experimental programmable quantum annealing optimizers that contain hundreds of quantum bits. These optimizers, commonly referred to as 'D-Wave' chips, promise to solve practical optimization problems potentially faster than conventional 'classical' computers. Attempts to quantify the quantum nature of these chips have been met with both excitement and skepticism but have also brought up numerous fundamental questions pertaining to the distinguishability of experimental quantum annealers from their classical thermal counterparts. Inspired by recent results in spin-glass theory that recognize 'temperature chaos' as the underlying mechanism responsible for the computational intractability of hard optimization problems, we devise a general method to quantify the performance of quantum annealers on optimization problems suffering from varying degrees of temperature chaos: A superior performance of quantum annealers over classical algorithms on these may allude to the role that quantum effects play in providing speedup. We utilize our method to experimentally study the D-Wave Two chip on different temperature-chaotic problems and find, surprisingly, that its performance scales unfavorably as compared to several analogous classical algorithms. We detect, quantify and discuss several purely classical effects that possibly mask the quantum behavior of the chip.

  9. Quantum-classical path integral. I. Classical memory and weak quantum nonlocality.

    PubMed

    Lambert, Roberto; Makri, Nancy

    2012-12-14

    We consider rigorous path integral descriptions of the dynamics of a quantum system coupled to a polyatomic environment, assuming that the latter is well approximated by classical trajectories. Earlier work has derived semiclassical or purely classical expressions for the influence functional from the environment, which should be sufficiently accurate for many situations, but the evaluation of quantum-(semi)classical path integral (QCPI) expressions has not been practical for large-scale simulation because the interaction with the environment introduces couplings nonlocal in time. In this work, we analyze the nature of the effects on a system from its environment in light of the observation [N. Makri, J. Chem. Phys. 109, 2994 (1998)] that true nonlocality in the path integral is a strictly quantum mechanical phenomenon. If the environment is classical, the path integral becomes local and can be evaluated in a stepwise fashion along classical trajectories of the free solvent. This simple "classical path" limit of QCPI captures fully the decoherence of the system via a classical mechanism. Small corrections to the classical path QCPI approximation may be obtained via an inexpensive random hop QCPI model, which accounts for some "back reaction" effects. Exploiting the finite length of nonlocality, we argue that further inclusion of quantum decoherence is possible via an iterative evaluation of the path integral. Finally, we show that the sum of the quantum amplitude factors with respect to the system paths leads to a smooth integrand as a function of trajectory initial conditions, allowing the use of Monte Carlo methods for the multidimensional phase space integral.

  10. Understanding the Planck blackbody spectrum and Landau diamagnetism within classical electromagnetism

    NASA Astrophysics Data System (ADS)

    Boyer, Timothy H.

    2016-11-01

    Electromagnetism is a relativistic theory, and one must exercise care in coupling this theory with nonrelativistic classical mechanics and with nonrelativistic classical statistical mechanics. Indeed historically, both the blackbody radiation spectrum and diamagnetism within classical theory have been misunderstood because of two crucial failures: (1) the neglect of classical electromagnetic zero-point radiation, and (2) the use of erroneous combinations of nonrelativistic mechanics with relativistic electrodynamics. Here we review the treatment of classical blackbody radiation, and show that the presence of Lorentz-invariant classical electromagnetic zero-point radiation can explain both the Planck blackbody spectrum and Landau diamagnetism at thermal equilibrium within classical electromagnetic theory. The analysis requires that relativistic electromagnetism is joined appropriately with simple nonrelativistic mechanical systems which can be regarded as the zero-velocity limits of relativistic systems, and that nonrelativistic classical statistical mechanics is applied only in the low-frequency limit when zero-point energy makes no contribution.

  11. The Aharonov-Bohm effect and classical potentials

    SciTech Connect

    Mijatovic, M.; Trencevski, K.; Veljanoski, B.

    1993-06-01

    Using the inverse scattering method we derive the classical potential which produces the same cross section as the Ahaxonov-Bohm effect. Because the potential is velocity dependent it shows that this effect of quantum scattering theory can reduce to non-potential classical mechanics, only. 7 refs., 3 figs.

  12. Classical system boundaries cannot be determined within quantum Darwinism

    NASA Astrophysics Data System (ADS)

    Fields, Chris

    Multiple observers who interact with environmental encodings of the states of a macroscopic quantum system S as required by quantum Darwinism cannot demonstrate that they are jointly observing S without a joint a priori assumption of a classical boundary separating S from its environment E. Quantum Darwinism cannot, therefore, be regarded as providing a purely quantum-mechanical explanation of the "emergence" of classicality.

  13. 40 CFR 761.208 - Obtaining manifests.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... PROHIBITIONS PCB Waste Disposal Records and Reports § 761.208 Obtaining manifests. (a)(1) A generator may use... print the manifest under 40 CFR 262.21 (c) and (e). A registered source may be a: (i) State agency; (ii) Commercial printer; (iii) PCB waste generator, transporter or, designated facility; or (iv) PCB waste...

  14. Teaching about Manifest Destiny: Clarifying the Concept.

    ERIC Educational Resources Information Center

    Chiodo, John J.

    2000-01-01

    Provides information on Manifest Destiny and the expansionist ideals of the United States, especially during the 19th century. Offers a lesson plan that will help students understand the concept of Manifest Destiny, including an assessment activity, how to expand the lesson, an appendix, and references. (CMK)

  15. Grassmannization of classical models

    NASA Astrophysics Data System (ADS)

    Pollet, Lode; Kiselev, Mikhail N.; Prokof'ev, Nikolay V.; Svistunov, Boris V.

    2016-11-01

    Applying Feynman diagrammatics to non-fermionic strongly correlated models with local constraints might seem generically impossible for two separate reasons: (i) the necessity to have a Gaussian (non-interacting) limit on top of which the perturbative diagrammatic expansion is generated by Wick’s theorem, and (ii) Dyson’s collapse argument implying that the expansion in powers of coupling constant is divergent. We show that for arbitrary classical lattice models both problems can be solved/circumvented by reformulating the high-temperature expansion (more generally, any discrete representation of the model) in terms of Grassmann integrals. Discrete variables residing on either links, plaquettes, or sites of the lattice are associated with the Grassmann variables in such a way that the partition function (as well as all correlation functions) of the original system and its Grassmann-field counterpart are identical. The expansion of the latter around its Gaussian point generates Feynman diagrams. Our work paves the way for studying lattice gauge theories by treating bosonic and fermionic degrees of freedom on equal footing.

  16. Extended symmetrical classical electrodynamics.

    PubMed

    Fedorov, A V; Kalashnikov, E G

    2008-03-01

    In this paper, we discuss a modification of classical electrodynamics in which "ordinary" point charges are absent. The modified equations contain additional terms describing the induced charges and currents. The densities of the induced charges and currents depend on the vector k and the vectors of the electromagnetic field, E and B . It is shown that the vectors E and B can be defined in terms of two four-potentials and the components of k are the components of a four-tensor of the third rank. The Lagrangian of the modified electrodynamics is defined. The conditions are derived at which only one four-potential determines the behavior of the electromagnetic field. It is also shown that static modified electrodynamics can describe the electromagnetic field in the inner region of an electric monopole. In the outer region of the electric monopole the electric field is governed by the Maxwell equations. It follows from boundary conditions at the interface between the inner and outer regions of the monopole that the vector k has a discrete spectrum. The electric and magnetic fields, energy, and angular momentum of the monopole are found for different eigenvalues of k .

  17. Genetic and antigenic heterogeneity among feline calicivirus isolates from distinct disease manifestations.

    PubMed

    Geissler, K; Schneider, K; Platzer, G; Truyen, B; Kaaden, O R; Truyen, U

    1997-05-01

    The capsid protein genes of five feline calicivirus (FCV) isolates associated with different disease manifestations were cloned and sequenced. The viruses represented two recent isolates from cats with chronic stomatitis, one recent isolate from a cat with acute stomatitis, one recent isolate each from a cat with acute respiratory symptoms and the classical limping syndrome strain FCV-2280. The amino acid sequences were compared with eight other published sequences and analyzed for their relationships. Phylogenetic analysis of the complete capsid protein sequences or of known antigenic regions of that protein (hypervariable regions A and E) did not group the isolates of different disease manifestations in distinct subclusters. Monoclonal antibodies (MAbs) generated against either a chronic stomatitis isolate or a recent isolate associated with respiratory symptoms were tested against a panel of 11 recent isolates and four "classical' FCV strains, covering all known disease associations. With those MAbs no obvious clustering with respect to disease manifestation could be seen. Four specific sera prepared in rabbits against our prototype isolates also failed to cluster those isolates according to the disease manifestations when examined in neutralization tests. From these antigenic and genetic analyses of the capsid protein the hypothesis of the existence of biotypes of FCV responsible for distinct disease manifestations could not be confirmed.

  18. Hypertonicity: Clinical entities, manifestations and treatment

    PubMed Central

    Rondon-Berrios, Helbert; Argyropoulos, Christos; Ing, Todd S; Raj, Dominic S; Malhotra, Deepak; Agaba, Emmanuel I; Rohrscheib, Mark; Khitan, Zeid J; Murata, Glen H; Shapiro, Joseph I; Tzamaloukas, Antonios H

    2017-01-01

    Hypertonicity causes severe clinical manifestations and is associated with mortality and severe short-term and long-term neurological sequelae. The main clinical syndromes of hypertonicity are hypernatremia and hyperglycemia. Hypernatremia results from relative excess of body sodium over body water. Loss of water in excess of intake, gain of sodium salts in excess of losses or a combination of the two are the main mechanisms of hypernatremia. Hypernatremia can be hypervolemic, euvolemic or hypovolemic. The management of hypernatremia addresses both a quantitative replacement of water and, if present, sodium deficit, and correction of the underlying pathophysiologic process that led to hypernatremia. Hypertonicity in hyperglycemia has two components, solute gain secondary to glucose accumulation in the extracellular compartment and water loss through hyperglycemic osmotic diuresis in excess of the losses of sodium and potassium. Differentiating between these two components of hypertonicity has major therapeutic implications because the first component will be reversed simply by normalization of serum glucose concentration while the second component will require hypotonic fluid replacement. An estimate of the magnitude of the relative water deficit secondary to osmotic diuresis is obtained by the corrected sodium concentration, which represents a calculated value of the serum sodium concentration that would result from reduction of the serum glucose concentration to a normal level. PMID:28101446

  19. Polyarthritis and membranoproliferative glomerulonephritis as paraneoplastic manifestation of Hodgkin's lymphoma: A case report and literature review.

    PubMed

    Erlij, Daniel; Calderón, Beatriz; Rivera, Angela; Mella, Cristián; Valladares, Ximena; Roessler, Emilio; Rivera, María Teresa; Méndez, Gonzalo

    2016-01-01

    Paraneoplastic syndromes can be presented in multiple ways, which include endocrinological, hematologic, rheumatologic and nephrologic manifestations. While most of the publications described solid tumors as responsible for these manifestations, hematologic neoplasms are important cause to consider as part of the differential diagnosis. We report the case of a 46 year-old man with seronegative symmetric polyarthritis of large and small joints associated with membranoproliferative glomerulonephritis with deposits of immune complexes and acute impairment of renal function, as part of a paraneoplastic syndrome secondary of a classical Hodgkin lymphoma with bone marrow invasion, which reversed completely with chemotherapy treatment.

  20. Brachial plexopathy as a rare presenting manifestation of scorpion envenomation.

    PubMed

    Rubin, Devon I; Vavra, Michael

    2011-07-01

    We report a patient who experienced a rare manifestation of an acute, severe brachial plexopathy as the initial complication of scorpion (presumed Hemiscorpius lepturus species) envenomation. Features suggesting conduction block, due to either proximal demyelination or ion channel dysfunction, along with axonal loss were seen on serial electrophysiological studies. Possible mechanisms of the brachial plexopathy include direct compression from tissue edema or a toxic effect on the membrane channels along the nerve.

  1. Innovation: the classic traps.

    PubMed

    Kanter, Rosabeth Moss

    2006-11-01

    Never a fad, but always in or out of fashion, innovation gets rediscovered as a growth enabler every half dozen years. Too often, though, grand declarations about innovation are followed by mediocre execution that produces anemic results, and innovation groups are quietly disbanded in cost-cutting drives. Each managerial generation embarks on the same enthusiastic quest for the next new thing. And each generation faces the same vexing challenges- most of which stem from the tensions between protecting existing revenue streams critical to current success and supporting new concepts that may be crucial to future success. In this article, Harvard Business School professor Rosabeth Moss Kanter reflects on the four major waves of innovation enthusiasm she's observed over the past 25 years. She describes the classic mistakes companies make in innovation strategy, process, structure, and skills assessment, illustrating her points with a plethora of real-world examples--including AT&T Worldnet, Timberland, and Ocean Spray. A typical strategic blunder is when managers set their hurdles too high or limit the scope of their innovation efforts. Quaker Oats, for instance, was so busy in the 1990s making minor tweaks to its product formulas that it missed larger opportunities in distribution. A common process mistake is when managers strangle innovation efforts with the same rigid planning, budgeting, and reviewing approaches they use in their existing businesses--thereby discouraging people from adapting as circumstances warrant. Companies must be careful how they structure fledgling entities alongside existing ones, Kanter says, to avoid a clash of cultures and agendas--which Arrow Electronics experienced in its attempts to create an online venture. Finally, companies commonly undervalue and underinvest in the human side of innovation--for instance, promoting individuals out of innovation teams long before their efforts can pay off. Kanter offers practical advice for avoiding

  2. A Classic Beauty

    NASA Technical Reports Server (NTRS)

    2007-01-01

    M51, whose name comes from being the 51st entry in Charles Messier's catalog, is considered to be one of the classic examples of a spiral galaxy. At a distance of about 30 million light-years from Earth, it is also one of the brightest spirals in the night sky. A composite image of M51, also known as the Whirlpool Galaxy, shows the majesty of its structure in a dramatic new way through several of NASA's orbiting observatories. X-ray data from NASA's Chandra X-ray Observatory reveals point-like sources (purple) that are black holes and neutron stars in binary star systems. Chandra also detects a diffuse glow of hot gas that permeates the space between the stars. Optical data from the Hubble Space Telescope (green) and infrared emission from the Spitzer Space Telescope (red) both highlight long lanes in the spiral arms that consist of stars and gas laced with dust. A view of M51 with the Galaxy Evolution Explorer telescope shows hot, young stars that produce lots of ultraviolet energy (blue).

    The textbook spiral structure is thought be the result of an interaction M51 is experiencing with its close galactic neighbor, NGC 5195, which is seen just above. Some simulations suggest M51's sharp spiral shape was partially caused when NGC 5195 passed through its main disk about 500 million years ago. This gravitational tug of war may also have triggered an increased level of star formation in M51. The companion galaxy's pull would be inducing extra starbirth by compressing gas, jump-starting the process by which stars form.

  3. Systemic manifestations of traumatic brain injury.

    PubMed

    Gaddam, Samson Sujit Kumar; Buell, Thomas; Robertson, Claudia S

    2015-01-01

    Traumatic brain injury (TBI) affects functioning of various organ systems in the absence of concomitant non-neurologic organ injury or systemic infection. The systemic manifestations of TBI can be mild or severe and can present in the acute phase or during the recovery phase. Non-neurologic organ dysfunction can manifest following mild TBI or severe TBI. The pathophysiology of systemic manifestations following TBI is multifactorial and involves an effect on the autonomic nervous system, involvement of the hypothalamic-pituitary axis, release of inflammatory mediators, and treatment modalities used for TBI. Endocrine dysfunction, electrolyte imbalance, and respiratory manifestations are common following TBI. The influence of TBI on systemic immune response, coagulation cascade, cardiovascular system, gastrointestinal system, and other systems is becoming more evident through animal studies and clinical trials. Systemic manifestations can independently act as risk factors for mortality and morbidity following TBI. Some conditions like neurogenic pulmonary edema and disseminated intravascular coagulation can adversely affect the outcome. Early recognition and treatment of systemic manifestations may improve the clinical outcome following TBI. Further studies are required especially in the field of neuroimmunology to establish the role of various biochemical cascades, not only in the pathophysiology of TBI but also in its systemic manifestations and outcome.

  4. [Lyme disease--clinical manifestations and treatment].

    PubMed

    Stock, Ingo

    2016-05-01

    Lyme disease (Lyme borreliosis) is a systemic infectious disease that can present in a variety of clinical manifestations. The disease is caused by a group of spirochaetes--Borrelia burgdorferi sensu lato or Lyme borrelia--that are transmitted to humans by the bite of Ixodes ticks. Lyme disease is the most common arthropode-borne infectious disease in many European countries including Germany. Early localized infection is typically manifested by an erythema migrans skin lesion, in rarer cases as a borrelial lymphocytoma. The most common early disseminated manifestation is (early) neuroborreliosis. In adults, neuroborreliosis appears typically as meningoradiculoneuritis. Neuroborreliosis in children, however, is typically manifested by meningitis. In addition, multiple erythema migrans lesions and Lyme carditis occur relatively frequently. The most common manifestation oflate Lyme disease is Lyme arthritis. Early manifestations (and usually also late manifestations) of Lyme disease can be treated successfully by application of suitable antibacterial agents. For the treatment of Lyme disease, doxycycline, certain penicillins such as amoxicillin and some cephalosporins (ceftriaxone, cefotaxime, cefuroxime axetil) are recommended in current guidelines. A major challenge is the treatment of chronic, non-specific disorders, i. e., posttreatment Lyme disease syndrome and "chronic Lyme disease". Prevention of Lyme disease is mainly accomplished by protecting against tick bites. Prophylactic administration of doxycycline after tick bites is generally not recommended in Germany. There is no vaccine available for human beings.

  5. Classical Analogs of a Diatomic Chain

    SciTech Connect

    Gutierrez, L.; Diaz-de-Anda, A.; Mendez-Sanchez, R. A.; Morales, A.; Flores, J.; Monsivais, G.

    2010-12-21

    Using one dimensional rods with different configurations classical analogs of quantum mechanical systems frequently used in solid state physics can be obtained. Among this analogs we have recently discussed locally periodic rods which lead to band spectra; the effect of a topological defect, and the Wannier Stark ladders. In this paper, we present an elastic analog of the diatomic chain and show how the acoustical and optical bands emerge, as well of the nature of the wave amplitudes.

  6. Genetic alterations in syndromes with oral manifestations.

    PubMed

    Anuthama, Krishnamurthy; Prasad, Harikrishnan; Ramani, Pratibha; Premkumar, Priya; Natesan, Anuja; Sherlin, Herald J

    2013-11-01

    Ever since Gregor Johan Mendel proposed the law of inheritance, genetics has transcended the field of health and has entered all walks of life in its application. Thus, the gene is the pivoting factor for all happenings revolving around it. Knowledge of gene mapping in various diseases would be a valuable tool in prenatally diagnosing the condition and averting the future disability and stigma for the posterity. This article includes an array of genetically determined conditions in patients seen at our college out-patient department with complete manifestation, partial manifestation and array of manifestations not fitting into a particular syndrome.

  7. Wegener Granulomatosis: Otologic Manifestation as First Symptom.

    PubMed

    Costa, Carla Fabiane da; Polanski, Jose Fernando

    2015-07-01

    Introduction Wegener granulomatosis is a systemic vasculitis affecting small and medium-sized vessels of the upper and lower respiratory tract and kidneys. Objective To describe a case of Wegener disease with atypical manifestation. Resumed Report We describe the case of a 50-year-old woman with chronic otitis media and sensorineural hearing loss as the primary symptoms, without other manifestations. Conclusion In cases of acute ear manifestations with or without hearing loss and with poor response to usual treatments, Wegener granulomatosis should be included among the possible etiologies. After adequate diagnoses and treatment of this rare disease, there was favorable evolution.

  8. Genetic alterations in syndromes with oral manifestations

    PubMed Central

    Anuthama, Krishnamurthy; Prasad, Harikrishnan; Ramani, Pratibha; Premkumar, Priya; Natesan, Anuja; Sherlin, Herald J.

    2013-01-01

    Ever since Gregor Johan Mendel proposed the law of inheritance, genetics has transcended the field of health and has entered all walks of life in its application. Thus, the gene is the pivoting factor for all happenings revolving around it. Knowledge of gene mapping in various diseases would be a valuable tool in prenatally diagnosing the condition and averting the future disability and stigma for the posterity. This article includes an array of genetically determined conditions in patients seen at our college out-patient department with complete manifestation, partial manifestation and array of manifestations not fitting into a particular syndrome. PMID:24379857

  9. Visual evoked potential findings in Behcet's disease without neurological manifestations.

    PubMed

    Anlar, Omer; Akdeniz, Necmettin; Tombul, Temel; Calka, Omer; Bilgili, Serap G

    2006-03-01

    Behçet's disease (BD) is a chronic, recurrent multisystem inflammatory disorder firstly described by Turkish dermatologist Dr. Hulusi Behçet in 1937. The classic triad consists of recurrent oral and genital ulcerations and uveitis. The article presents the value of visual evoked potential findings of a series of 44 patients with BD without neurological manifestations seen at the Medical Hospital in Neurology and Dermatology clinics over the past 8 years. The mean latency value of positive peak P100 in BD patients was significantly delayed compared to that of control subjects (patients's mean: 105.6 ms in right eye and 107.7 ms in left eye; control subject's mean: 101.4 ms in right eye and 101.7 ms in left eye).

  10. The multiple electrocardiographic manifestations of ventricular repolarization memory.

    PubMed

    Chiale, Pablo A; Etcheverry, Daniel; Pastori, Julio D; Fernandez, Pablo A; Garro, Hugo A; González, Mario D; Elizari, Marcelo V

    2014-08-01

    T wave "memory" is a peculiar variety of cardiac remodeling caused by a transient change in the course of ventricular depolarization (due to ventricular pacing, rate-dependent intraventricular block, ventricular preexcitation or tachyarrhythmias with wide QRS complexes). It is usually manifested by inverted T waves that appears when normal ventricular activation is restored. This phenomenon is cumulative and occurs earlier if the ventricular myocardium has previously been exposed to the same conditioning stimuli. In this article the different conditions giving rise to "classical" T wave memory development are reviewed and also "another" type of T wave memory is described. It is also shown that cardiac memory may induce not only negative (pseudo-primary) T waves but also a reversal of primary and pseudoprimary T waves leading to "normalization" of ventricular repolarization. The knowledge of these dissimilar consequences of T wave memory is essential to assess the characteristics of ventricular repolarization.

  11. Relaxation properties in classical diamagnetism

    NASA Astrophysics Data System (ADS)

    Carati, A.; Benfenati, F.; Galgani, L.

    2011-06-01

    It is an old result of Bohr that, according to classical statistical mechanics, at equilibrium a system of electrons in a static magnetic field presents no magnetization. Thus a magnetization can occur only in an out of equilibrium state, such as that produced through the Foucault currents when a magnetic field is switched on. It was suggested by Bohr that, after the establishment of such a nonequilibrium state, the system of electrons would quickly relax back to equilibrium. In the present paper, we study numerically the relaxation to equilibrium in a modified Bohr model, which is mathematically equivalent to a billiard with obstacles, immersed in a magnetic field that is adiabatically switched on. We show that it is not guaranteed that equilibrium is attained within the typical time scales of microscopic dynamics. Depending on the values of the parameters, one has a relaxation either to equilibrium or to a diamagnetic (presumably metastable) state. The analogy with the relaxation properties in the Fermi Pasta Ulam problem is also pointed out.

  12. Pembrolizumab in classical Hodgkin's lymphoma.

    PubMed

    Maly, Joseph; Alinari, Lapo

    2016-09-01

    Pembrolizumab is a humanized monoclonal antibody directed against programmed cell death protein 1 (PD-1), a key immune-inhibitory molecule expressed on T cells and implicated in CD4+ T-cell exhaustion and tumor immune-escape mechanisms. Classical Hodgkin's lymphoma (cHL) is a unique B-cell malignancy in the sense that malignant Reed-Sternberg (RS) cells represent a small percentage of cells within an extensive immune cell infiltrate. PD-1 ligands are upregulated on RS cells as a consequence of both chromosome 9p24.1 amplification and Epstein-Barr virus infection and by interacting with PD-1 promote an immune-suppressive effect. By augmenting antitumor immune response, pembrolizumab and nivolumab, another monoclonal antibody against PD-1, have shown significant activity in patients with relapsed/refractory cHL as well as an acceptable toxicity profile with immune-related adverse events that are generally manageable. In this review, we explore the rationale for targeting PD-1 in cHL, review the clinical trial results supporting the use of checkpoint inhibitors in this disease, and present future directions for investigation in which this approach may be used.

  13. Teaching and Demonstrating Classical Conditioning.

    ERIC Educational Resources Information Center

    Sparrow, John; Fernald, Peter

    1989-01-01

    Discusses classroom demonstrations of classical conditioning and notes tendencies to misrepresent Pavlov's procedures. Describes the design and construction of the conditioner that is used for demonstrating classical conditioning. Relates how students experience conditioning, generalization, extinction, discrimination, and spontaneous recovery.…

  14. Classical models of the spin 1/2 system

    NASA Astrophysics Data System (ADS)

    Salazar-Lazaro, Carlos H.

    We proposed a Quaternionic mechanical system motivated by the Foucault pendulum as a classical model for the dynamics of the spin ½ system. We showed that this mechanical system contains the dynamics of the spin state of the electron under a uniform magnetic field as it is given by the Schrodinger-Pauli-Equation (SPE). We closed with a characterization of the dynamics of this generalized classical system by showing that it is equivalent with the dynamics of the Schrodinger Pauli Equation as long as the solutions to the generalized classical system are roots of the Lagrangian, that is the condition L = 0 holds.

  15. Unraveling Quantum Annealers using Classical Hardness

    NASA Astrophysics Data System (ADS)

    Martin-Mayor, Victor; Hen, Itay

    2015-10-01

    Recent advances in quantum technology have led to the development and manufacturing of experimental programmable quantum annealing optimizers that contain hundreds of quantum bits. These optimizers, commonly referred to as ‘D-Wave’ chips, promise to solve practical optimization problems potentially faster than conventional ‘classical’ computers. Attempts to quantify the quantum nature of these chips have been met with both excitement and skepticism but have also brought up numerous fundamental questions pertaining to the distinguishability of experimental quantum annealers from their classical thermal counterparts. Inspired by recent results in spin-glass theory that recognize ‘temperature chaos’ as the underlying mechanism responsible for the computational intractability of hard optimization problems, we devise a general method to quantify the performance of quantum annealers on optimization problems suffering from varying degrees of temperature chaos: A superior performance of quantum annealers over classical algorithms on these may allude to the role that quantum effects play in providing speedup. We utilize our method to experimentally study the D-Wave Two chip on different temperature-chaotic problems and find, surprisingly, that its performance scales unfavorably as compared to several analogous classical algorithms. We detect, quantify and discuss several purely classical effects that possibly mask the quantum behavior of the chip.

  16. Classic hallucinogens in the treatment of addictions.

    PubMed

    Bogenschutz, Michael P; Johnson, Matthew W

    2016-01-04

    Addictive disorders are very common and have devastating individual and social consequences. Currently available treatment is moderately effective at best. After many years of neglect, there is renewed interest in potential clinical uses for classic hallucinogens in the treatment of addictions and other behavioral health conditions. In this paper we provide a comprehensive review of both historical and recent clinical research on the use of classic hallucinogens in the treatment of addiction, selectively review other relevant research concerning hallucinogens, and suggest directions for future research. Clinical trial data are very limited except for the use of LSD in the treatment of alcoholism, where a meta-analysis of controlled trials has demonstrated a consistent and clinically significant beneficial effect of high-dose LSD. Recent pilot studies of psilocybin-assisted treatment of nicotine and alcohol dependence had strikingly positive outcomes, but controlled trials will be necessary to evaluate the efficacy of these treatments. Although plausible biological mechanisms have been proposed, currently the strongest evidence is for the role of mystical or other meaningful experiences as mediators of therapeutic effects. Classic hallucinogens have an excellent record of safety in the context of clinical research. Given our limited understanding of the clinically relevant effects of classic hallucinogens, there is a wealth of opportunities for research that could contribute important new knowledge and potentially lead to valuable new treatments for addiction.

  17. On the emergence of classical gravity

    NASA Astrophysics Data System (ADS)

    Larjo, Klaus

    In this thesis I will discuss how certain black holes arise as an effective, thermodynamical description from non-singular microstates in string theory. This provides a possible solution to the information paradox, and strengthens the case for treating black holes as thermodynamical objects. I will characterize the data defining a microstate of a black hole in several settings, and demonstrate that most of the data is unmeasurable for a classical observer. I will further show that the data that is measurable is universal for nearly all microstates, making it impossible for a classical observer to distinguish between microstates, thus giving rise to an effective statistical description for the black hole. In the first half of the thesis I will work with two specific systems: the half-BPS sector of [Special characters omitted.] = 4 super Yang-Mills the and the conformal field theory corresponding to the D1/D5 system; in both cases the high degree of symmetry present provides great control over potentially intractable computations. For these systems, I will further specify the conditions a quantum mechanical microstate must satisfy in order to have a classical description in terms of a unique metric, and define a 'metric operator' whose eigenstates correspond to classical geometries. In the second half of the thesis I will consider a much broader setting, general [Special characters omitted.] = I superconformal quiver gauge the= ories and their dual gravity theories, and demonstrate that a similar effective description arises also in this setting.

  18. Unraveling Quantum Annealers using Classical Hardness

    PubMed Central

    Martin-Mayor, Victor; Hen, Itay

    2015-01-01

    Recent advances in quantum technology have led to the development and manufacturing of experimental programmable quantum annealing optimizers that contain hundreds of quantum bits. These optimizers, commonly referred to as ‘D-Wave’ chips, promise to solve practical optimization problems potentially faster than conventional ‘classical’ computers. Attempts to quantify the quantum nature of these chips have been met with both excitement and skepticism but have also brought up numerous fundamental questions pertaining to the distinguishability of experimental quantum annealers from their classical thermal counterparts. Inspired by recent results in spin-glass theory that recognize ‘temperature chaos’ as the underlying mechanism responsible for the computational intractability of hard optimization problems, we devise a general method to quantify the performance of quantum annealers on optimization problems suffering from varying degrees of temperature chaos: A superior performance of quantum annealers over classical algorithms on these may allude to the role that quantum effects play in providing speedup. We utilize our method to experimentally study the D-Wave Two chip on different temperature-chaotic problems and find, surprisingly, that its performance scales unfavorably as compared to several analogous classical algorithms. We detect, quantify and discuss several purely classical effects that possibly mask the quantum behavior of the chip. PMID:26483257

  19. Classical enhancement of quantum vacuum fluctuations

    NASA Astrophysics Data System (ADS)

    De Lorenci, V. A.; Ford, L. H.

    2017-01-01

    We propose a mechanism for the enhancement of vacuum fluctuations by means of a classical field. The basic idea is that if an observable quantity depends quadratically upon a quantum field, such as the electric field, then the application of a classical field produces a cross term between the classical and quantum fields. This cross term may be significantly larger than the purely quantum part, but also undergoes fluctuations driven by the quantum field. We illustrate this effect in a model for light-cone fluctuations involving pulses in a nonlinear dielectric. Vacuum electric field fluctuations produce fluctuations in the speed of a probe pulse, and form an analog model for quantum gravity effects. If the material has a nonzero third-order susceptibility, then the fractional light speed fluctuations are proportional to the square of the fluctuating electric field. Hence the application of a classical electric field can enhance the speed fluctuations. We give an example where this enhancement can be an increase of 1 order of magnitude, increasing the possibility of observing the effect.

  20. Important cutaneous manifestations of inflammatory bowel disease

    PubMed Central

    Trost, L; McDonnell, J

    2005-01-01

    Inflammatory bowel disease (IBD) has many extraintestinal manifestations. Cutaneous manifestations are usually related to the activity of the bowel disease but may have an independent course. Anyone presenting with IBD should be examined for cutaneous manifestations. Pyoderma gangrenosum is a severe painful ulcerating disease that requires moist wound management and, in the absence of secondary infection, systemic corticosteroids, cyclosporine, or both. Infliximab may also be used. Erythema nodosum is a common cause of tender red nodules of the shins. Management includes leg elevation, NSAIDs, and potassium iodide. Oral manifestations of IBD include aphthous stomatitis, mucosal nodularity (cobblestoning), and pyostomatitis vegetans. Treatment should be directed both at the cutaneous lesions and at the underlying systemic condition. PMID:16143688

  1. Musculoskeletal manifestations of the antiphospholipid syndrome.

    PubMed

    Noureldine, M H A; Khamashta, M A; Merashli, M; Sabbouh, T; Hughes, G R V; Uthman, I

    2016-04-01

    The scope of clinical and laboratory manifestations of the antiphospholipid syndrome (APS) has increased dramatically since its discovery in 1983, where any organ system can be involved. Musculoskeletal complications are consistently reported in APS patients, not only causing morbidity and mortality, but also affecting their quality of life. We reviewed all English papers on APS involvement in the musculoskeletal system using Google Scholar and Pubmed; all reports are summarized in a table in this review. The spectrum of manifestations includes arthralgia/arthritis, avascular necrosis of bone, bone marrow necrosis, complex regional pain syndrome type-1, muscle infarction, non-traumatic fractures, and osteoporosis. Some of these manifestations were reported in good quality studies, some of which showed an association between aPL-positivity and the occurrence of these manifestations, while others were merely described in case reports.

  2. 19 CFR 122.75 - Complete manifest.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... represent a full and complete enumeration and description of the cargo carried in this flight except that... manifests: Attached Shipper's Export Declarations represent a full and complete enumeration and...

  3. 19 CFR 122.75 - Complete manifest.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... represent a full and complete enumeration and description of the cargo carried in this flight except that... manifests: Attached Shipper's Export Declarations represent a full and complete enumeration and...

  4. 19 CFR 122.75 - Complete manifest.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... represent a full and complete enumeration and description of the cargo carried in this flight except that... manifests: Attached Shipper's Export Declarations represent a full and complete enumeration and...

  5. 19 CFR 122.75 - Complete manifest.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... represent a full and complete enumeration and description of the cargo carried in this flight except that... manifests: Attached Shipper's Export Declarations represent a full and complete enumeration and...

  6. Cutaneous manifestations of dermatomyositis and their management.

    PubMed

    Callen, Jeffrey P

    2010-06-01

    Dermatomyositis is a condition with pathognomonic and characteristic cutaneous lesions. This article describes the skin manifestations observed in patients with dermatomyositis, their differential diagnosis, their relationship to internal disease (particularly malignancy), and their management.

  7. Mucocutaneous manifestations of helminth infections: Nematodes.

    PubMed

    Lupi, Omar; Downing, Christopher; Lee, Michael; Pino, Livia; Bravo, Francisco; Giglio, Patricia; Sethi, Aisha; Klaus, Sidney; Sangueza, Omar P; Fuller, Claire; Mendoza, Natalia; Ladizinski, Barry; Woc-Colburn, Laila; Tyring, Stephen K

    2015-12-01

    In the 21st century, despite increased globalization through international travel for business, medical volunteerism, pleasure, and immigration/refugees into the United States, there is little published in the dermatology literature regarding the cutaneous manifestations of helminth infections. Approximately 17% of travelers seek medical care because of cutaneous disorders, many related to infectious etiologies. This review will focus on the cutaneous manifestations of helminth infections and is divided into 2 parts: part I focuses on nematode infections, and part II focuses on trematode and cestode infections. This review highlights the clinical manifestations, transmission, diagnosis, and treatment of helminth infections. Nematodes are roundworms that cause diseases with cutaneous manifestations, such as cutaneous larval migrans, onchocerciasis, filariasis, gnathostomiasis, loiasis, dracunculiasis, strongyloidiasis, ascariasis, streptocerciasis, dirofilariasis, and trichinosis. Tremadotes, also known as flukes, cause schistosomiasis, paragonimiasis, and fascioliasis. Cestodes (tapeworms) are flat, hermaphroditic parasites that cause diseases such as sparganosis, cysticercosis, and echinococcus.

  8. Endocrine disorders and the neurologic manifestations

    PubMed Central

    2014-01-01

    The nervous system and the endocrine system are closely interrelated and both involved intimately in maintaining homeostasis. Endocrine dysfunctions may lead to various neurologic manifestations such as headache, myopathy, and acute encephalopathy including coma. It is important to recognize the neurologic signs and symptoms caused by the endocrine disorders while managing endocrine disorders. This article provides an overview of the neurologic manifestations found in various endocrine disorders that affect pediatric patients. It is valuable to think about 'endocrine disorder' as a cause of the neurologic manifestations. Early diagnosis and treatment of hormonal imbalance can rapidly relieve the neurologic symptoms. Better understanding of the interaction between the endocrine system and the nervous system, combined with the knowledge about the pathophysiology of the neurologic manifestations presented in the endocrine disorders might allow earlier diagnosis and better treatment of the endocrine disorders. PMID:25654063

  9. Autoimmune bullous skin diseases. Part 1: Clinical manifestations.

    PubMed

    Kneisel, Andrea; Hertl, Michael

    2011-10-01

    Autoimmune bullous skin diseases are characterized by autoantibodies against adhesion molecules of the skin. Pemphigus is a disorder with an intraepidermal loss of adhesion and is characterized by fragile blisters and erosions. Pemphigus vulgaris often shows extensive lesions of the oral mucosa, while pemphigus foliaceus is commonly restricted to cutaneous involvement with puff pastry-like scale formation. Paraneoplastic pemphigus is obligatorily associated with malignancies and often presents as hemorrhagic stomatitis with multiforme-like exanthems. IgA pemphigus typically presents with pustules and annular plaques but not with mucosal involvement. The clinical spectrum of the pemphigoids includes tense blisters, urticarial plaques, and prurigo- like eczematous lesions. Pemphigoid gestationis mostly occurs during the last trimester of pregnancy and mucous membrane pemphigoid primarily involves the oral mucosa and conjunctivae and leads to scarring. Linear IgA bullous dermatosis manifests with tense blisters in a "cluster of jewels"-like pattern in childhood and is more heterogeneous in adulthood. Classical epidermolysis bullosa acquisita shows extensive skin fragility. Dermatitis herpetiformis is associated with gluten-sensitive enteropathy and manifests clinically with severe itching and papulovesicles on the extensor surfaces of the extremities and the lumbosacral area. The intention of the review is to demonstrate the heterogeneous clinical spectrum of autoimmune bullous disorders.

  10. Quantum dynamics in open quantum-classical systems.

    PubMed

    Kapral, Raymond

    2015-02-25

    Often quantum systems are not isolated and interactions with their environments must be taken into account. In such open quantum systems these environmental interactions can lead to decoherence and dissipation, which have a marked influence on the properties of the quantum system. In many instances the environment is well-approximated by classical mechanics, so that one is led to consider the dynamics of open quantum-classical systems. Since a full quantum dynamical description of large many-body systems is not currently feasible, mixed quantum-classical methods can provide accurate and computationally tractable ways to follow the dynamics of both the system and its environment. This review focuses on quantum-classical Liouville dynamics, one of several quantum-classical descriptions, and discusses the problems that arise when one attempts to combine quantum and classical mechanics, coherence and decoherence in quantum-classical systems, nonadiabatic dynamics, surface-hopping and mean-field theories and their relation to quantum-classical Liouville dynamics, as well as methods for simulating the dynamics.

  11. Computational quantum-classical boundary of noisy commuting quantum circuits

    NASA Astrophysics Data System (ADS)

    Fujii, Keisuke; Tamate, Shuhei

    2016-05-01

    It is often said that the transition from quantum to classical worlds is caused by decoherence originated from an interaction between a system of interest and its surrounding environment. Here we establish a computational quantum-classical boundary from the viewpoint of classical simulatability of a quantum system under decoherence. Specifically, we consider commuting quantum circuits being subject to decoherence. Or equivalently, we can regard them as measurement-based quantum computation on decohered weighted graph states. To show intractability of classical simulation in the quantum side, we utilize the postselection argument and crucially strengthen it by taking noise effect into account. Classical simulatability in the classical side is also shown constructively by using both separable criteria in a projected-entangled-pair-state picture and the Gottesman-Knill theorem for mixed state Clifford circuits. We found that when each qubit is subject to a single-qubit complete-positive-trace-preserving noise, the computational quantum-classical boundary is sharply given by the noise rate required for the distillability of a magic state. The obtained quantum-classical boundary of noisy quantum dynamics reveals a complexity landscape of controlled quantum systems. This paves a way to an experimentally feasible verification of quantum mechanics in a high complexity limit beyond classically simulatable region.

  12. Computational quantum-classical boundary of noisy commuting quantum circuits

    PubMed Central

    Fujii, Keisuke; Tamate, Shuhei

    2016-01-01

    It is often said that the transition from quantum to classical worlds is caused by decoherence originated from an interaction between a system of interest and its surrounding environment. Here we establish a computational quantum-classical boundary from the viewpoint of classical simulatability of a quantum system under decoherence. Specifically, we consider commuting quantum circuits being subject to decoherence. Or equivalently, we can regard them as measurement-based quantum computation on decohered weighted graph states. To show intractability of classical simulation in the quantum side, we utilize the postselection argument and crucially strengthen it by taking noise effect into account. Classical simulatability in the classical side is also shown constructively by using both separable criteria in a projected-entangled-pair-state picture and the Gottesman-Knill theorem for mixed state Clifford circuits. We found that when each qubit is subject to a single-qubit complete-positive-trace-preserving noise, the computational quantum-classical boundary is sharply given by the noise rate required for the distillability of a magic state. The obtained quantum-classical boundary of noisy quantum dynamics reveals a complexity landscape of controlled quantum systems. This paves a way to an experimentally feasible verification of quantum mechanics in a high complexity limit beyond classically simulatable region. PMID:27189039

  13. Beyond quantum-classical analogies: high time for agreement?

    NASA Astrophysics Data System (ADS)

    Marrocco, Michele

    Lately, many quantum-classical analogies have been investigated and published in many acknowledged journals. Such a surge of research on conceptual connections between quantum and classical physics forces us to ask whether the correspondence between the quantum and classical interpretation of the reality is deeper than the correspondence principle stated by Bohr. Here, after a short introduction to quantum-classical analogies from the recent literature, we try to examine the question from the perspective of a possible agreement between quantum and classical laws. A paradigmatic example is given in the striking equivalence between the classical Mie theory of electromagnetic scattering from spherical scatterers and the corresponding quantum-mechanical wave scattering analyzed in terms of partial waves. The key features that make the correspondence possible are examined and finally employed to deal with the fundamental blackbody problem that marks the initial separation between classical and quantum physics. The procedure allows us to recover the blackbody spectrum in classical terms and the proof is rich in consequences. Among them, the strong analogy between the quantum vacuum and its classical counterpart.

  14. Computational quantum-classical boundary of noisy commuting quantum circuits.

    PubMed

    Fujii, Keisuke; Tamate, Shuhei

    2016-05-18

    It is often said that the transition from quantum to classical worlds is caused by decoherence originated from an interaction between a system of interest and its surrounding environment. Here we establish a computational quantum-classical boundary from the viewpoint of classical simulatability of a quantum system under decoherence. Specifically, we consider commuting quantum circuits being subject to decoherence. Or equivalently, we can regard them as measurement-based quantum computation on decohered weighted graph states. To show intractability of classical simulation in the quantum side, we utilize the postselection argument and crucially strengthen it by taking noise effect into account. Classical simulatability in the classical side is also shown constructively by using both separable criteria in a projected-entangled-pair-state picture and the Gottesman-Knill theorem for mixed state Clifford circuits. We found that when each qubit is subject to a single-qubit complete-positive-trace-preserving noise, the computational quantum-classical boundary is sharply given by the noise rate required for the distillability of a magic state. The obtained quantum-classical boundary of noisy quantum dynamics reveals a complexity landscape of controlled quantum systems. This paves a way to an experimentally feasible verification of quantum mechanics in a high complexity limit beyond classically simulatable region.

  15. Metabolic and hormonal signatures in pre-manifest and manifest Huntington's disease patients.

    PubMed

    Wang, Rui; Ross, Christopher A; Cai, Huan; Cong, Wei-Na; Daimon, Caitlin M; Carlson, Olga D; Egan, Josephine M; Siddiqui, Sana; Maudsley, Stuart; Martin, Bronwen

    2014-01-01

    Huntington's disease (HD) is an inherited neurodegenerative disorder typified by involuntary body movements, and psychiatric and cognitive abnormalities. Many HD patients also exhibit metabolic changes including progressive weight loss and appetite dysfunction. Here we have investigated metabolic function in pre-manifest and manifest HD subjects to establish an HD subject metabolic hormonal plasma signature. Individuals at risk for HD who have had predictive genetic testing showing the cytosine-adenine-guanine (CAG) expansion causative of HD, but who do not yet present signs and symptoms sufficient for the diagnosis of manifest HD are said to be "pre-manifest." Pre-manifest and manifest HD patients, as well as both familial and non-familial controls, were evaluated for multiple peripheral metabolism signals including circulating levels of hormones, growth factors, lipids, and cytokines. Both pre-manifest and manifest HD subjects exhibited significantly reduced levels of circulating growth factors, including growth hormone and prolactin. HD-related changes in the levels of metabolic hormones such as ghrelin, glucagon, and amylin were also observed. Total cholesterol, HDL-C, and LDL-C were significantly decreased in HD subjects. C-reactive protein was significantly elevated in pre-manifest HD subjects. The observation of metabolic alterations, even in subjects considered to be in the pre-manifest stage of HD, suggests that in addition, and prior, to overt neuronal damage, HD affects metabolic hormone secretion and energy regulation, which may shed light on pathogenesis, and provide opportunities for biomarker development.

  16. Targeted deletion of collagen V in tendons and ligaments results in a classic Ehlers-Danlos syndrome joint phenotype.

    PubMed

    Sun, Mei; Connizzo, Brianne K; Adams, Sheila M; Freedman, Benjamin R; Wenstrup, Richard J; Soslowsky, Louis J; Birk, David E

    2015-05-01

    Collagen V mutations underlie classic Ehlers-Danlos syndrome, and joint hypermobility is an important clinical manifestation. We define the function of collagen V in tendons and ligaments, as well as the role of alterations in collagen V expression in the pathobiology in classic Ehlers-Danlos syndrome. A conditional Col5a1(flox/flox) mouse model was bred with Scleraxis-Cre mice to create a targeted tendon and ligament Col5a1-null mouse model, Col5a1(Δten/Δten). Targeting was specific, resulting in collagen V-null tendons and ligaments. Col5a1(Δten/Δten) mice demonstrated decreased body size, grip weakness, abnormal gait, joint laxity, and early-onset osteoarthritis. These gross changes were associated with abnormal fiber organization, as well as altered collagen fibril structure with increased fibril diameters and decreased fibril number that was more severe in a major joint stabilizing ligament, the anterior cruciate ligament (ACL), than in the flexor digitorum longus tendon. The ACL also had a higher collagen V content than did the flexor digitorum longus tendon. The collagen V-null ACL and flexor digitorum longus tendon both had significant alterations in mechanical properties, with ACL exhibiting more severe changes. The data demonstrate critical differential regulatory roles for collagen V in tendon and ligament structure and function and suggest that collagen V regulatory dysfunction is associated with an abnormal joint phenotype, similar to the hypermobility phenotype in classic Ehlers-Danlos syndrome.

  17. Neuromuscular Manifestations of West Nile Virus Infection

    PubMed Central

    Leis, A. Arturo; Stokic, Dobrivoje S.

    2012-01-01

    The most common neuromuscular manifestation of West Nile virus (WNV) infection is a poliomyelitis syndrome with asymmetric paralysis variably involving one (monoparesis) to four limbs (quadriparesis), with or without brainstem involvement and respiratory failure. This syndrome of acute flaccid paralysis may occur without overt fever or meningoencephalitis. Although involvement of anterior horn cells in the spinal cord and motor neurons in the brainstem are the major sites of pathology responsible for neuromuscular signs, inflammation also may involve skeletal or cardiac muscle (myositis, myocarditis), motor axons (polyradiculitis), and peripheral nerves [Guillain–Barré syndrome (GBS), brachial plexopathy]. In addition, involvement of spinal sympathetic neurons and ganglia provides an explanation for autonomic instability seen in some patients. Many patients also experience prolonged subjective generalized weakness and disabling fatigue. Despite recent evidence that WNV may persist long-term in the central nervous system or periphery in animals, the evidence in humans is controversial. WNV persistence would be of great concern in immunosuppressed patients or in those with prolonged or recurrent symptoms. Support for the contention that WNV can lead to autoimmune disease arises from reports of patients presenting with various neuromuscular diseases that presumably involve autoimmune mechanisms (GBS, other demyelinating neuropathies, myasthenia gravis, brachial plexopathies, stiff-person syndrome, and delayed or recurrent symptoms). Although there is no specific treatment or vaccine currently approved in humans, and the standard remains supportive care, drugs that can alter the cascade of immunobiochemical events leading to neuronal death may be potentially useful (high-dose corticosteroids, interferon preparations, and intravenous immune globulin containing WNV-specific antibodies). Human experience with these agents seems promising based on anecdotal reports

  18. Quantum reduplication of classical solitons

    NASA Astrophysics Data System (ADS)

    Sveshnikov, Konstantin

    1993-09-01

    The possible existence of a series of quantum copies of classical soliton solutions is discussed, which do not exist when the effective Planck constant of the theory γ tends to zero. Within the conventional weak-coupling expansion in √ γ such non-classical solitons are O(√ γ) in energy and therefore lie in between the true classical solutions and elementary quantum excitations. Analytic results concerning the shape functions, masses and characteristic scales of such quantum excitations are given for soliton models of a self-interacting scalar field. Stability properties and quantization of fluctuations in the neighborhood of these configurations are also discussed in detail.

  19. Classical and quantum Malus laws

    NASA Astrophysics Data System (ADS)

    Wódkiewicz, Krzysztof

    1995-04-01

    The classical and the quantum Malus laws for light and spin are discussed. It is shown that for spin 1/2, the quantum Malus law is equivalent in form to the classical Malus law provided the statistical average involves a quasidistribution function that can become negative. A generalization of Malus's law for arbitrary spin s is obtained in the form of a Feynman path-integral representation for the Malus amplitude. The classical limit of the Malus amplitude for s-->∞ is discussed.

  20. Advancements in Pharmacotherapy for Noncancerous Manifestations of HPV

    PubMed Central

    Kollipara, Ramya; Ekhlassi, Erfon; Downing, Christopher; Guidry, Jacqueline; Lee, Michael; Tyring, Stephen K.

    2015-01-01

    Human papillomavirus (HPV) is the most common sexually transmitted disease. Via infection of the basal epithelial cells, HPV causes numerous malignancies and noncancerous cutaneous manifestations. Noncancerous cutaneous manifestations of HPV, including common, plantar, plane, and anogenital warts, are among the most common reasons for an office visit. Although there are various therapies available, they are notoriously difficult to treat. HPV treatments can be grouped into destructive (cantharidin, salicylic acid), virucidal (cidofovir, interferon-α), antimitotic (bleomycin, podophyllotoxin, 5-fluorouracil), immunotherapy (Candida antigen, contact allergen immunotherapy, imiquimod) or miscellaneous (trichloroacetic acid, polyphenon E). The mechanism of action, recent efficacy data, safety profile and recommended regimen for each of these treatment modalities is discussed. PMID:26239450

  1. Toxocara infection and its association with allergic manifestations.

    PubMed

    Pinelli, Elena; Aranzamendi, Carmen

    2012-03-01

    Toxocara canis and Toxocara cati are roundworms of dogs and cats that can also infect humans worldwide. Although these parasites do not reach the adult stage in the human host the larvae migrate to different organs and can persist for many years. Migration of larvae through the lungs may result in respiratory distress such as wheezing, coughs, mucous production and hyper-reactivity of the airways. Epidemiological and experimental studies suggest that infection with this helminth contributes to the development of allergic manifestations, including asthma. These findings are however conflicting since in others studies no association between these two immunopathologies has been found. This article reviews information on Toxocara spp. and findings from epidemiological and experimental studies on the association between Toxocara infection and allergic manifestations. In addition, the immunological mechanisms and the factors involved in the helminth allergy-association are discussed.

  2. Oral Manifestations and Dental Management of Epidermolysis Bullosa Simplex

    PubMed Central

    Scheidt, Lisa; Sanabe, Mariane Emi

    2015-01-01

    ABSTRACT Epidermolysis bullosa (EB) is a group of hereditary chronic disorders, characterized by fragility of the skin and mucous membranes in response to minor mechanical trauma. The objective of this study was to report the case of a young girl diagnosed with epidermolysis bullosa simplex (EBS), transmitted by an autosomal dominant gene. Cutaneous findings included blisters and dystrophy following minimal friction. Recurrent blisters and vesicle formation on the hard palate were the main oral findings. In conclusion, publications concerning the oral and clinical manifestations of EBS are important for providing knowledge and an early multidisciplinary approach that prevents blister formation and improves these patients’ quality of life, with the dentist playing an important role in oral health management. How to cite this article: Scheidt L, Sanabe ME, Diniz MB. Oral Manifestations and Dental Management of Epidermolysis Bullosa Simplex. Int J Clin Pediatr Dent 2015;8(3):239-241. PMID:26604545

  3. FSH isoform pattern in classic galactosemia.

    PubMed

    Gubbels, Cynthia S; Thomas, Chris M G; Wodzig, Will K W H; Olthaar, André J; Jaeken, Jaak; Sweep, Fred C G J; Rubio-Gozalbo, M Estela

    2011-04-01

    Female classic galactosemia patients suffer from primary ovarian insufficiency (POI). The cause for this long-term complication is not fully understood. One of the proposed mechanisms is that hypoglycosylation of complex molecules, a known secondary phenomenon of galactosemia, leads to FSH dysfunction. An earlier study showed less acidic isoforms of FSH in serum samples of two classic galactosemia patients compared to controls, indicating hypoglycosylation. In this study, FSH isoform patterns of five classic galactosemia patients with POI were compared to the pattern obtained in two patients with a primary glycosylation disorder (phosphomannomutase-2-deficient congenital disorders of glycosylation, PMM2-CDG) and POI, and in five postmenopausal women as controls. We used FPLC chromatofocussing with measurement of FSH concentration per fraction, and discovered that there were no significant differences between galactosemia patients, PMM2-CDG patients and postmenopausal controls. Our results do not support that FSH dysfunction due to a less acidic isoform pattern because of hypoglycosylation is a key mechanism of POI in this disease.

  4. Characterization of Classical and Nonclassical Fabry Disease: A Multicenter Study.

    PubMed

    Arends, Maarten; Wanner, Christoph; Hughes, Derralynn; Mehta, Atul; Oder, Daniel; Watkinson, Oliver T; Elliott, Perry M; Linthorst, Gabor E; Wijburg, Frits A; Biegstraaten, Marieke; Hollak, Carla E

    2016-12-15

    Fabry disease leads to renal, cardiac, and cerebrovascular manifestations. Phenotypic differences between classically and nonclassically affected patients are evident, but there are few data on the natural course of classical and nonclassical disease in men and women. To describe the natural course of Fabry disease stratified by sex and phenotype, we retrospectively assessed event-free survival from birth to the first clinical visit (before enzyme replacement therapy) in 499 adult patients (mean age 43 years old; 41% men; 57% with the classical phenotype) from three international centers of excellence. We classified patients by phenotype on the basis of characteristic symptoms and enzyme activity. Men and women with classical Fabry disease had higher event rate than did those with nonclassical disease (hazard ratio for men, 5.63, 95% confidence interval, 3.17 to 10.00; P<0.001; hazard ratio for women, 2.88, 95% confidence interval, 1.54 to 5.40; P<0.001). Furthermore, men with classical Fabry disease had lower eGFR, higher left ventricular mass, and higher plasma globotriaosylsphingosine concentrations than men with nonclassical Fabry disease or women with either phenotype (P<0.001). In conclusion, before treatment with enzyme replacement therapy, men with classical Fabry disease had a history of more events than men with nonclassical disease or women with either phenotype; women with classical Fabry disease were more likely to develop complications than women with nonclassical disease. These data may support the development of new guidelines for the monitoring and treatment of Fabry disease and studies on the effects of intervention in subgroups of patients.

  5. Hidden invariance of the free classical particle

    SciTech Connect

    Garcia, S. )

    1994-06-01

    A formalism describing the dynamics of classical and quantum systems from a group theoretical point of view is presented. We apply it to the simple example of the classical free particle. The Galileo group [ital G] is the symmetry group of the free equations of motion. Consideration of the free particle Lagrangian semi-invariance under [ital G] leads to a larger symmetry group, which is a central extension of the Galileo group by the real numbers. We study the dynamics associated with this group, and characterize quantities like Noether invariants and evolution equations in terms of group geometric objects. An extension of the Galileo group by [ital U](1) leads to quantum mechanics.

  6. Experimental contextuality in classical light

    PubMed Central

    Li, Tao; Zeng, Qiang; Song, Xinbing; Zhang, Xiangdong

    2017-01-01

    The Klyachko, Can, Binicioglu, and Shumovsky (KCBS) inequality is an important contextuality inequality in three-level system, which has been demonstrated experimentally by using quantum states. Using the path and polarization degrees of freedom of classical optics fields, we have constructed the classical trit (cetrit), tested the KCBS inequality and its geometrical form (Wright’s inequality) in this work. The projection measurement has been implemented, the clear violations of the KCBS inequality and its geometrical form have been observed. This means that the contextuality inequality, which is commonly used in test of the conflict between quantum theory and noncontextual realism, may be used as a quantitative tool in classical optical coherence to describe correlation characteristics of the classical fields. PMID:28291227

  7. Classical Foundations: Leah Rochel Johnson

    ERIC Educational Resources Information Center

    Lum, Lydia

    2005-01-01

    This article discusses the accomplishments of Leah Rochel Johnson, Assistant Professor of Classics and Ancient Mediterranean Studies and History, Pennsylvania State University. It provides insight into her values and beliefs and testimony from those who work most closely with her.

  8. Experimental contextuality in classical light

    NASA Astrophysics Data System (ADS)

    Li, Tao; Zeng, Qiang; Song, Xinbing; Zhang, Xiangdong

    2017-03-01

    The Klyachko, Can, Binicioglu, and Shumovsky (KCBS) inequality is an important contextuality inequality in three-level system, which has been demonstrated experimentally by using quantum states. Using the path and polarization degrees of freedom of classical optics fields, we have constructed the classical trit (cetrit), tested the KCBS inequality and its geometrical form (Wright’s inequality) in this work. The projection measurement has been implemented, the clear violations of the KCBS inequality and its geometrical form have been observed. This means that the contextuality inequality, which is commonly used in test of the conflict between quantum theory and noncontextual realism, may be used as a quantitative tool in classical optical coherence to describe correlation characteristics of the classical fields.

  9. Quantum money with classical verification

    SciTech Connect

    Gavinsky, Dmitry

    2014-12-04

    We propose and construct a quantum money scheme that allows verification through classical communication with a bank. This is the first demonstration that a secure quantum money scheme exists that does not require quantum communication for coin verification. Our scheme is secure against adaptive adversaries - this property is not directly related to the possibility of classical verification, nevertheless none of the earlier quantum money constructions is known to possess it.

  10. New Perspective on Classical Electromagnetism

    DTIC Science & Technology

    2013-04-01

    R. Feynman , R. Leighton, and M. Sands, The Feynman Lectures in Physics vol II (Addison-Wesley, Reading, MA, 1964). 6. W.K.H. Panofsky and M...of the basics of classical electromagnetism is provided by recognizing a previously overlooked law of induction as well as the physical reality of the...classical electromagnetism is provided by recognizing a previously overlooked law of induction as well as the physical reality of the vector potential

  11. Classical theory of radiating strings

    NASA Technical Reports Server (NTRS)

    Copeland, Edmund J.; Haws, D.; Hindmarsh, M.

    1990-01-01

    The divergent part of the self force of a radiating string coupled to gravity, an antisymmetric tensor and a dilaton in four dimensions are calculated to first order in classical perturbation theory. While this divergence can be absorbed into a renormalization of the string tension, demanding that both it and the divergence in the energy momentum tensor vanish forces the string to have the couplings of compactified N = 1 D = 10 supergravity. In effect, supersymmetry cures the classical infinities.

  12. Quantum money with classical verification

    NASA Astrophysics Data System (ADS)

    Gavinsky, Dmitry

    2014-12-01

    We propose and construct a quantum money scheme that allows verification through classical communication with a bank. This is the first demonstration that a secure quantum money scheme exists that does not require quantum communication for coin verification. Our scheme is secure against adaptive adversaries - this property is not directly related to the possibility of classical verification, nevertheless none of the earlier quantum money constructions is known to possess it.

  13. 19 CFR 123.22 - In-transit manifest.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... transported under Customs red in-bond seals and is accompanied by a transportation in-bond manifest, a.... (c) Manifest forms to be used. The in-transit manifest forms to be used are: (1) For trucks,...

  14. Dissipative Forces and Quantum Mechanics

    ERIC Educational Resources Information Center

    Eck, John S.; Thompson, W. J.

    1977-01-01

    Shows how to include the dissipative forces of classical mechanics in quantum mechanics by the use of non-Hermetian Hamiltonians. The Ehrenfest theorem for such Hamiltonians is derived, and simple examples which show the classical correspondences are given. (MLH)

  15. Classical vs. non-classical pathways of mineral formation (Invited)

    NASA Astrophysics Data System (ADS)

    De Yoreo, J. J.

    2013-12-01

    Recent chemical analyses, microscopy studies and computer simulations suggest many minerals nucleate through aggregation of pre-nucleation clusters and grow by particle-mediated processes that involve amorphous or disordered precursors. Still other analyses, both experimental and computational, conclude that even simple mineral systems like calcium carbonate form via a barrier-free process of liquid-liquid separation, which is followed by dehydration of the ion-rich phase to form the solid products. However, careful measurements of calcite nucleation rates on a variety of ionized surfaces give results that are in complete agreement with the expectations of classical nucleation theory, in which clusters growing through ion-by-ion addition overcome a free energy barrier through the natural microscopic density fluctuations of the system. Here the challenge of integrating these seemingly disparate observations and analyses into a coherent picture of mineral formation is addressed by considering the energy barriers to calcite formation predicted by the classical theory and the changes in those barriers brought about by the introduction of interfaces and clusters, both stable and metastable. Results from a suite of in situ TEM, AFM, and optical experiments combined with simulations are used to illustrate the conclusions. The analyses show that the expected barrier to homogeneous calcite nucleation is prohibitive even at concentrations exceeding the solubility limit of amorphous calcium carbonate. However, as demonstrated by experiments on self-assembled monolayers, the introduction of surfaces that moderately decrease the interfacial energy associated with the forming nucleus can reduce the magnitude of the barrier to a level that is easily surmounted under typical laboratory conditions. In the absence of such surfaces, experiments that proceed by continually increasing supersaturation with time can easily by-pass direct nucleation of calcite and open up pathways through

  16. Nocturnal manifestations of atypical parkinsonian disorders.

    PubMed

    Bhidayasiri, Roongroj; Jitkritsadakul, Onanong; Colosimo, Carlo

    2014-01-01

    Although nocturnal disturbances are increasingly recognized as an integral part of the continuum of daytime manifestations of Parkinson's disease (PD), there is still little evidence in the medical literature to support the occurrence of these complex phenomena in patients with atypical parkinsonian disorders (APDs). Based on the anatomical substrates in APDs, which are considered to be more extensive outside the basal ganglia than in PD, we might expect that patients with APDs encounter the whole range of nocturnal disturbances, including motor, sleep disorders, autonomic dysfunctions, and neuropsychiatric manifestations at a similar, or even greater, frequency than in PD. This article is a review of the current literature on the problems at nighttime of patients with progressive supranuclear palsy, multiple system atrophy, corticobasal degeneration, and dementia with Lewy bodies. MEDLINE, life science journals and online books were searched by querying appropriate key words. Reports were included if the studies were related to nocturnal manifestations in APDs. Forty articles fulfilled the selection criteria. Differences between these symptoms in APDs and PD are highlighted, given the evidence available about each manifestation. This analysis of nocturnal manifestations of APDs suggests the need for future studies to address these issues to improve the quality of life not only of patients with APDs but the caregivers who encounter the challenges of supporting these patients on a daily basis.

  17. Pulmonary drug toxicity: radiologic and pathologic manifestations.

    PubMed

    Rossi, S E; Erasmus, J J; McAdams, H P; Sporn, T A; Goodman, P C

    2000-01-01

    Pulmonary drug toxicity is increasingly being diagnosed as a cause of acute and chronic lung disease. Numerous agents including cytotoxic and noncytotoxic drugs have the potential to cause pulmonary toxicity. The clinical and radiologic manifestations of these drugs generally reflect the underlying histopathologic processes and include diffuse alveolar damage (DAD), nonspecific interstitial pneumonia (NSIP), bronchiolitis obliterans organizing pneumonia (BOOP), eosinophilic pneumonia, obliterative bronchiolitis, pulmonary hemorrhage, edema, hypertension, or veno-occlusive disease. DAD is a common manifestation of pulmonary drug toxicity and is frequently caused by cytotoxic drugs, especially cyclophosphamide, bleomycin, and carmustine. It manifests radiographically as bilateral hetero- or homogeneous opacities usually in the mid and lower lungs and on high-resolution computed tomographic (CT) scans as scattered or diffuse areas of ground-glass opacity. NSIP occurs most commonly as a manifestation of carmustine toxicity or of toxicity from noncytotoxic drugs such as amidarone. At radiography, it appears as diffuse areas of heterogeneous opacity, whereas early CT scans show diffuse ground-glass opacity and late CT scans show fibrosis in a basal distribution. BOOP, which is commonly caused by bleomycin and cyclophosphamide (as well as gold salts and methotrexate), appears on radiographs as hetero- and homogeneous peripheral opacities in both upper and lower lobes and on CT scans as poorly defined nodular consolidation, centrilobular nodules, and bronchial dilatation. Knowledge of these manifestations and of the drugs most frequently involved can facilitate diagnosis and institution of appropriate treatment.

  18. Black thyroid: clinical manifestations, ultrastructural findings, and possible mechanisms

    SciTech Connect

    Alexander, C.B.; Herrera, G.A.; Jaffe, K.; Yu, H.

    1985-01-01

    Ultrastructural examination of three black thyroid glands showed lysosomal accumulations of lipofuscin-like pigment and granular electron-dense material in association with 1) a minocycline-associated black thyroid with normal thyroid function; 2) a minocycline-associated black thyroid with a significant inflammatory component, fibrosis, and primary hypothyroidism; and 3) a black thyroid gland with no exposure to minocycline. The deposition of the pigments in the three cases resulted in macroscopically recognizable black thyroid glands. It is speculated that an imbalance in lysosomal function accounts for this abnormality. The glandular hypofunction documented in case 2 is unique and confirms the need to monitor function carefully in patients who are receiving minocycline. In one case electrondense deposits were identified in the thyroid gland interstitium.

  19. Disease Manifestations and Pathogenic Mechanisms of Group A Streptococcus

    PubMed Central

    Barnett, Timothy C.; McArthur, Jason D.; Cole, Jason N.; Gillen, Christine M.; Henningham, Anna; Sriprakash, K. S.; Sanderson-Smith, Martina L.; Nizet, Victor

    2014-01-01

    SUMMARY Streptococcus pyogenes, also known as group A Streptococcus (GAS), causes mild human infections such as pharyngitis and impetigo and serious infections such as necrotizing fasciitis and streptococcal toxic shock syndrome. Furthermore, repeated GAS infections may trigger autoimmune diseases, including acute poststreptococcal glomerulonephritis, acute rheumatic fever, and rheumatic heart disease. Combined, these diseases account for over half a million deaths per year globally. Genomic and molecular analyses have now characterized a large number of GAS virulence determinants, many of which exhibit overlap and redundancy in the processes of adhesion and colonization, innate immune resistance, and the capacity to facilitate tissue barrier degradation and spread within the human host. This improved understanding of the contribution of individual virulence determinants to the disease process has led to the formulation of models of GAS disease progression, which may lead to better treatment and intervention strategies. While GAS remains sensitive to all penicillins and cephalosporins, rising resistance to other antibiotics used in disease treatment is an increasing worldwide concern. Several GAS vaccine formulations that elicit protective immunity in animal models have shown promise in nonhuman primate and early-stage human trials. The development of a safe and efficacious commercial human vaccine for the prophylaxis of GAS disease remains a high priority. PMID:24696436

  20. The endocrine manifestations of anorexia nervosa: mechanisms and management.

    PubMed

    Schorr, Melanie; Miller, Karen K

    2017-03-01

    Anorexia nervosa is a psychiatric disorder characterized by altered body image, persistent food restriction and low body weight, and is associated with global endocrine dysregulation in both adolescent girls and women. Dysfunction of the hypothalamic-pituitary axis includes hypogonadotropic hypogonadism with relative oestrogen and androgen deficiency, growth hormone resistance, hypercortisolaemia, non-thyroidal illness syndrome, hyponatraemia and hypooxytocinaemia. Serum levels of leptin, an anorexigenic adipokine, are suppressed and levels of ghrelin, an orexigenic gut peptide, are elevated in women with anorexia nervosa; however, levels of peptide YY, an anorexigenic gut peptide, are paradoxically elevated. Although most, but not all, of these endocrine disturbances are adaptive to the low energy state of chronic starvation and reverse with treatment of the eating disorder, many contribute to impaired skeletal integrity, as well as neuropsychiatric comorbidities, in individuals with anorexia nervosa. Although 5-15% of patients with anorexia nervosa are men, only limited data exist regarding the endocrine impact of the disease in adolescent boys and men. Further research is needed to understand the endocrine determinants of bone loss and neuropsychiatric comorbidities in anorexia nervosa in both women and men, as well as to formulate optimal treatment strategies.

  1. Classical trajectory versus quantum interference. A linear chain model for the origin of uncertainty broadening

    SciTech Connect

    Tang, Jau

    1996-02-01

    A simple linear chain model, as an alternative to the orthodox Schroedinger approach, is proposed to explain the origin of the uncertainty broadening and to improve our physical insight into the difference between classical and quantum worlds. Quantum interference in space is manifested as a result of fast exchange between adjacent particles of different internal degrees of freedom.

  2. Path-integral approach to 't Hooft's derivation of quantum physics from classical physics

    SciTech Connect

    Blasone, Massimo; Jizba, Petr; Kleinert, Hagen

    2005-05-15

    We present a path-integral formulation of 't Hooft's derivation of quantum physics from classical physics. The crucial ingredient of this formulation is Gozzi et al.'s supersymmetric path integral of classical mechanics. We quantize explicitly two simple classical systems: the planar mathematical pendulum and the Roessler dynamical system.

  3. Mesoscopic systems: classical irreversibility and quantum coherence.

    PubMed

    Barbara, Bernard

    2012-09-28

    Mesoscopic physics is a sub-discipline of condensed-matter physics that focuses on the properties of solids in a size range intermediate between bulk matter and individual atoms. In particular, it is characteristic of a domain where a certain number of interacting objects can easily be tuned between classical and quantum regimes, thus enabling studies at the border of the two. In magnetism, such a tuning was first realized with large-spin magnetic molecules called single-molecule magnets (SMMs) with archetype Mn(12)-ac. In general, the mesoscopic scale can be relatively large (e.g. micrometre-sized superconducting circuits), but, in magnetism, it is much smaller and can reach the atomic scale with rare earth (RE) ions. In all cases, it is shown how quantum relaxation can drastically reduce classical irreversibility. Taking the example of mesoscopic spin systems, the origin of irreversibility is discussed on the basis of the Landau-Zener model. A classical counterpart of this model is described enabling, in particular, intuitive understanding of most aspects of quantum spin dynamics. The spin dynamics of mesoscopic spin systems (SMM or RE systems) becomes coherent if they are well isolated. The study of the damping of their Rabi oscillations gives access to most relevant decoherence mechanisms by different environmental baths, including the electromagnetic bath of microwave excitation. This type of decoherence, clearly seen with spin systems, is easily recovered in quantum simulations. It is also observed with other types of qubits such as a single spin in a quantum dot or a superconducting loop, despite the presence of other competitive decoherence mechanisms. As in the molecular magnet V(15), the leading decoherence terms of superconducting qubits seem to be associated with a non-Markovian channel in which short-living entanglements with distributions of two-level systems (nuclear spins, impurity spins and/or charges) leading to 1/f noise induce τ(1)-like

  4. Cutaneous Manifestations of Systemic Lupus Erythematosus

    PubMed Central

    Uva, Luís; Miguel, Diana; Pinheiro, Catarina; Freitas, João Pedro; Marques Gomes, Manuel; Filipe, Paulo

    2012-01-01

    Systemic lupus erythematosus (SLE) is a multiorgan autoimmune disease of unknown etiology with many clinical manifestations. The skin is one of the target organs most variably affected by the disease. The American College of Rheumatology (ACR) established 11 criteria as a classificatory instrument to operationalise the definition of SLE in clinical trials. They were not intended to be used to diagnose individuals and do not do well in that capacity. Cutaneous lesions account for four of these 11 revised criteria of SLE. Skin lesions in patients with lupus may be specific or nonspecific. This paper covers the SLE-specific cutaneous changes: malar rash, discoid rash, photosensitivity, and oral mucosal lesions as well as SLE nonspecific skin manifestations, their pathophysiology, and management. A deeper thorough understanding of the cutaneous manifestations of SLE is essential for diagnosis, prognosis, and efficient management. Thus, dermatologists should cooperate with other specialties to provide optimal care of SLE patient. PMID:22888407

  5. Ocular manifestations in systemic lupus erythematosus.

    PubMed

    Silpa-archa, Sukhum; Lee, Joan J; Foster, C Stephen

    2016-01-01

    Systemic lupus erythematosus (SLE) can involve many parts of the eye, including the eyelid, ocular adnexa, sclera, cornea, uvea, retina and optic nerve. Ocular manifestations of SLE are common and may lead to permanent blindness from the underlying disease or therapeutic side effects. Keratoconjunctivitis sicca is the most common manifestation. However, vision loss may result from involvement of the retina, choroid and optic nerve. Ocular symptoms are correlated to systemic disease activity and can present as an initial manifestation of SLE. The established treatment includes prompt systemic corticosteroids, steroid-sparing immunosuppressive drugs and biological agents. Local ocular therapies are options with promising efficacy. The early recognition of disease and treatment provides reduction of visual morbidity and mortality.

  6. Planck's radiation law: is a quantum-classical perspective possible?

    NASA Astrophysics Data System (ADS)

    Marrocco, Michele

    2016-05-01

    Planck's radiation law provides the solution to the blackbody problem that marks the decline of classical physics and the rise of the quantum theory of the radiation field. Here, we venture to suggest the possibility that classical physics might be equally suitable to deal with the blackbody problem. A classical version of the Planck's radiation law seems to be achievable if we learn from the quantum-classical correspondence between classical Mie theory and quantum-mechanical wave scattering from spherical scatterers (partial wave analysis). This correspondence designs a procedure for countable energy levels of the radiation trapped within the blackbody treated within the multipole approach of classical electrodynamics (in place of the customary and problematic expansion in terms of plane waves that give rise to the ultraviolet catastrophe). In turn, introducing the Boltzmann discretization of energy levels, the tools of classical thermodynamics and statistical theory become available for the task. On the other hand, the final result depends on a free parameter whose physical units are those of an action. Tuning this parameter on the value given by the Planck constant makes the classical result agree with the canonical Planck's radiation law.

  7. Caffeine-induced psychiatric manifestations: a review.

    PubMed

    Wang, Hee Ryung; Woo, Young Sup; Bahk, Won-Myong

    2015-07-01

    The association between caffeine consumption and various psychiatric manifestations has long been observed. We present two cases that show the ability of caffeine to induce psychotic and manic symptoms, and we also review the extant literature on caffeine-induced psychiatric manifestations. On the basis of our own and others' findings, we suggest that caffeine may be related to not only de-novo psychotic or mood symptoms but also to aggravation of pre-existing psychotic or mood disorders. We therefore suggest that caffeine consumption among patients with mood or psychotic symptoms should be assessed carefully in clinical practice as part of routine psychiatric evaluations.

  8. Ocular manifestations of Mycoplasma pneumoniae infection.

    PubMed

    Salzman, M B; Sood, S K; Slavin, M L; Rubin, L G

    1992-05-01

    Ocular manifestations of Mycoplasma pneumoniae infection, other than conjunctivitis, are uncommon. Optic disk swelling, optic nerve atrophy, retinal exudates and hemorrhages, and cranial nerve palsies have been infrequently reported. We describe a 15-year-old patient who developed bilateral optic disk edema and iritis during an acute infection with M. pneumoniae and review the world literature on findings associated with ocular manifestations of infection with this pathogen. Although our patient experienced complete resolution of iritis and optic disk edema after 6 weeks, several patients described in the literature have experienced permanent sequelae as a result of optic neuropathy.

  9. Superimposed segmental manifestation of cherry angiomas.

    PubMed

    Jaeger, Teresa; Andres, Christian; Hein, Rüdiger; Ring, Johannes; Chen, Wenchieh

    2011-01-01

    Cherry angioma is a common, acquired, vascular proliferation, probably of a polygenic mode of inheritance. Segmental manifestation of multiple cherry angiomas associated with the development of non-segmental lesions has not yet been reported. We describe a 62-year-old Caucasian woman with early formation of segmental cherry angiomas after pregnancy, which are superimposed on non-segmental lesions of later onset after menopause. In this pattern, segmental cherry angiomas could be taken as a further example of superimposed segmental manifestation of a polygenic skin disorder. Molecular research would be needed to confirm this hypothesis.

  10. Bodily manifestations in the psychoanalytic process.

    PubMed

    Vartzopoulos, Ioannis; Beratis, Stavroula

    2012-07-01

    The broadening scope of psychoanalysis has brought to the fore patients whose unconscious conflicts tend to be literally played out on the stage of the body. In these cases, the body seems to be predominantly used in a concrete, not symbolic, way in order to express underlying conflicts. In a similar vein, transference and countertransference can be manifested via the body. The authors briefly discuss some of the literature on body-mind issues, and then present an extended case report to illustrate bodily manifestations in the psychoanalytic process.

  11. Quantum-Classical Correspondence of Shortcuts to Adiabaticity

    NASA Astrophysics Data System (ADS)

    Okuyama, Manaka; Takahashi, Kazutaka

    2017-04-01

    We formulate the theory of shortcuts to adiabaticity in classical mechanics. For a reference Hamiltonian, the counterdiabatic term is constructed from the dispersionless Korteweg-de Vries (KdV) hierarchy. Then the adiabatic theorem holds exactly for an arbitrary choice of time-dependent parameters. We use the Hamilton-Jacobi theory to define the generalized action. The action is independent of the history of the parameters and is directly related to the adiabatic invariant. The dispersionless KdV hierarchy is obtained from the classical limit of the KdV hierarchy for the quantum shortcuts to adiabaticity. This correspondence suggests some relation between the quantum and classical adiabatic theorems.

  12. The diffracted distribution of classical trajectories and interference between electrons

    NASA Astrophysics Data System (ADS)

    Zhao, Guo-Peng; Zhang, Yan-Hui; Cai, Xiang-Ji; Xu, Xiu-Lan; Kang, Li-Sha

    2016-10-01

    We use a semiclassical approximation to study the escape of electrons through a circular mesostructure with the diffractive effect at the entrance lead taken into consideration. We find that the fluctuating shapes of the escape probability manifests a good agreement with the diffracted distributions of the incident angles for different transverse modes, and show that several classical trajectories with certain lengths have prominent contributions on the escape probability. In addition, we define the coherence factor to investigate the interference between electrons for different transverse modes and we find that it is the coherent backscattering that is responsible for the prominent interference. Moreover, we find there is a good correspondence between the distribution of classical trajectories and the time-reversed path.

  13. Unbiased estimators for spatial distribution functions of classical fluids.

    PubMed

    Adib, Artur B; Jarzynski, Christopher

    2005-01-01

    We use a statistical-mechanical identity closely related to the familiar virial theorem, to derive unbiased estimators for spatial distribution functions of classical fluids. In particular, we obtain estimators for both the fluid density rho(r) in the vicinity of a fixed solute and the pair correlation g(r) of a homogeneous classical fluid. We illustrate the utility of our estimators with numerical examples, which reveal advantages over traditional histogram-based methods of computing such distributions.

  14. Classical approach in atomic physics

    NASA Astrophysics Data System (ADS)

    Solov'ev, E. A.

    2011-12-01

    The application of a classical approach to various quantum problems - the secular perturbation approach to quantization of a hydrogen atom in external fields and a helium atom, the adiabatic switching method for calculation of a semiclassical spectrum of a hydrogen atom in crossed electric and magnetic fields, a spontaneous decay of excited states of a hydrogen atom, Gutzwiller's approach to Stark problem, long-lived excited states of a helium atom discovered with the help of Poincaré section, inelastic transitions in slow and fast electron-atom and ion-atom collisions - is reviewed. Further, a classical representation in quantum theory is discussed. In this representation the quantum states are treated as an ensemble of classical states. This approach opens the way to an accurate description of the initial and final states in classical trajectory Monte Carlo (CTMC) method and a purely classical explanation of tunneling phenomenon. The general aspects of the structure of the semiclassical series such as renormgroup symmetry, criterion of accuracy and so on are reviewed as well.

  15. Hermeneutic reading of classic texts.

    PubMed

    Koskinen, Camilla A-L; Lindström, Unni Å

    2013-09-01

    The purpose of this article is to broaden the understandinfg of the hermeneutic reading of classic texts. The aim is to show how the choice of a specific scientific tradition in conjunction with a methodological approach creates the foundation that clarifies the actual realization of the reading. This hermeneutic reading of classic texts is inspired by Gadamer's notion that it is the researcher's own research tradition and a clearly formulated theoretical fundamental order that shape the researcher's attitude towards texts and create the starting point that guides all reading, uncovering and interpretation. The researcher's ethical position originates in a will to openness towards what is different in the text and which constantly sets the researcher's preunderstanding and research tradition in movement. It is the researcher's attitude towards the text that allows the text to address, touch and arouse wonder. Through a flexible, lingering and repeated reading of classic texts, what is different emerges with a timeless value. The reading of classic texts is an act that may rediscover and create understanding for essential dimensions and of human beings' reality on a deeper level. The hermeneutic reading of classic texts thus brings to light constantly new possibilities of uncovering for a new envisioning and interpretation for a new understanding of the essential concepts and phenomena within caring science.

  16. Classical Hamiltonian structures in wave packet dynamics

    NASA Astrophysics Data System (ADS)

    Gray, Stephen K.; Verosky, John M.

    1994-04-01

    The general, N state matrix representation of the time-dependent Schrödinger equation is equivalent to an N degree of freedom classical Hamiltonian system. We describe how classical mechanical methods and ideas can be applied towards understanding and modeling exact quantum dynamics. Two applications are presented. First, we illustrate how qualitative insights may be gained by treating the two state problem with a time-dependent coupling. In the case of periodic coupling, Poincaré surfaces of section are used to view the quantum dynamics, and features such as the Floquet modes take on interesting interpretations. The second application illustrates computational implications by showing how Liouville's theorem, or more generally the symplectic nature of classical Hamiltonian dynamics, provides a new perspective for carrying out numerical wave packet propagation. We show how certain simple and explicit symplectic integrators can be used to numerically propagate wave packets. The approach is illustrated with an application to the problem of a diatomic molecule interacting with a laser, although it and related approaches may be useful for describing a variety of problems.

  17. Classical Antiferromagnetism in Kinetically Frustrated Electronic Models

    NASA Astrophysics Data System (ADS)

    Sposetti, C. N.; Bravo, B.; Trumper, A. E.; Gazza, C. J.; Manuel, L. O.

    2014-05-01

    We study, by means of the density matrix renormalization group, the infinite U Hubbard model—with one hole doped away from half filling—in triangular and square lattices with frustrated hoppings, which invalidate Nagaoka's theorem. We find that these kinetically frustrated models have antiferromagnetic ground states with classical local magnetization in the thermodynamic limit. We identify the mechanism of this kinetic antiferromagnetism with the release of the kinetic energy frustration, as the hole moves in the established antiferromagnetic background. This release can occur in two different ways: by a nontrivial spin Berry phase acquired by the hole, or by the effective vanishing of the hopping amplitude along the frustrating loops.

  18. Classical light beams and geometric phases.

    PubMed

    Mukunda, N; Chaturvedi, S; Simon, R

    2014-06-01

    We present a study of geometric phases in classical wave and polarization optics using the basic mathematical framework of quantum mechanics. Important physical situations taken from scalar wave optics, pure polarization optics, and the behavior of polarization in the eikonal or ray limit of Maxwell's equations in a transparent medium are considered. The case of a beam of light whose propagation direction and polarization state are both subject to change is dealt with, attention being paid to the validity of Maxwell's equations at all stages. Global topological aspects of the space of all propagation directions are discussed using elementary group theoretical ideas, and the effects on geometric phases are elucidated.

  19. Quantum remnants in the classical limit

    NASA Astrophysics Data System (ADS)

    Kowalski, A. M.; Plastino, A.

    2016-09-01

    We analyze here the common features of two dynamical regimes: a quantum and a classical one. We deal with a well known semi-classic system in its route towards the classical limit, together with its purely classic counterpart. We wish to ascertain i) whether some quantum remnants can be found in the classical limit and ii) the details of the quantum-classic transition. The so-called mutual information is the appropriate quantifier for this task. Additionally, we study the Bandt-Pompe's symbolic patterns that characterize dynamical time series (representative of the semi-classical system under scrutiny) in their evolution towards the classical limit.

  20. Peripheral nervous system manifestations in systemic autoimmune diseases.

    PubMed

    Cojocaru, Inimioara Mihaela; Cojocaru, Manole; Silosi, Isabela; Vrabie, Camelia Doina

    2014-09-01

    The peripheral nervous system refers to parts of the nervous system outside the brain and spinal cord. Systemic autoimmune diseases can affect both the central and peripheral nervous systems in a myriad of ways and through a heterogeneous number of mechanisms leading to many different clinical manifestations. As a result, neurological complications of these disorders can result in significant morbidity and mortality. The most common complication of peripheral nervous system (PNS) involvement is peripheral neuropathy, with symptoms of numbness, sensory paresthesias, weakness, or gait imbalance. The neuropathy may be multifocal and asymmetric or, less frequently, distal and symmetric.