Nonlinear, nonbinary cyclic group codes
NASA Technical Reports Server (NTRS)
Solomon, G.
1992-01-01
New cyclic group codes of length 2(exp m) - 1 over (m - j)-bit symbols are introduced. These codes can be systematically encoded and decoded algebraically. The code rates are very close to Reed-Solomon (RS) codes and are much better than Bose-Chaudhuri-Hocquenghem (BCH) codes (a former alternative). The binary (m - j)-tuples are identified with a subgroup of the binary m-tuples which represents the field GF(2 exp m). Encoding is systematic and involves a two-stage procedure consisting of the usual linear feedback register (using the division or check polynomial) and a small table lookup. For low rates, a second shift-register encoding operation may be invoked. Decoding uses the RS error-correcting procedures for the m-tuple codes for m = 4, 5, and 6.
Constructions of new families of nonbinary quantum codes
La Guardia, Giuliano G.
2009-10-15
Three code constructions generating new families of good nonbinary quantum codes are presented in this paper. The first two ones are derived from Hermitian self-orthogonal non-narrow-sense Bose-Chaudhuri-Hocquenghem (BCH) codes. The third one is derived from q-ary (q{ne}2 is a prime power) Steane's enlargement of Calderbank-Shor-Steane codes applied to Euclidean self-orthogonal non-narrow-sense BCH codes. The quantum nonbinary BCH codes presented here have parameters better than the ones available in the literature.
Non-binary unitary error bases and quantum codes
Knill, E.
1996-06-01
Error operator bases for systems of any dimension are defined and natural generalizations of the bit-flip/ sign-change error basis for qubits are given. These bases allow generalizing the construction of quantum codes based on eigenspaces of Abelian groups. As a consequence, quantum codes can be constructed form linear codes over {ital Z}{sub {ital n}} for any {ital n}. The generalization of the punctured code construction leads to many codes which permit transversal (i.e. fault tolerant) implementations of certain operations compatible with the error basis.
Cyclic universe from Loop Quantum Gravity
NASA Astrophysics Data System (ADS)
Cianfrani, Francesco; Kowalski-Glikman, Jerzy; Rosati, Giacomo
2016-02-01
We discuss how a cyclic model for the flat universe can be constructively derived from Loop Quantum Gravity. This model has a lower bounce, at small values of the scale factor, which shares many similarities with that of Loop Quantum Cosmology. We find that Quantum Gravity corrections can be also relevant at energy densities much smaller than the Planckian one and that they can induce an upper bounce at large values of the scale factor.
Quantum diffusion on a cyclic one-dimensional lattice
NASA Astrophysics Data System (ADS)
de La Torre, A. C.; Mártin, H. O.; Goyeneche, D.
2003-09-01
The quantum diffusion of a particle in an initially localized state on a cyclic lattice with N sites is studied. Diffusion and reconstruction time are calculated. Strong differences are found for even or odd number of sites and the limit N→∞ is studied. The predictions of the model could be tested with microtechnology and nanotechnology devices.
Reconciliation with Non-Binary Species Trees
Vernot, Benjamin; Stolzer, Maureen; Goldman, Aiton
2008-01-01
Abstract Reconciliation extracts information from the topological incongruence between gene and species trees to infer duplications and losses in the history of a gene family. The inferred duplication-loss histories provide valuable information for a broad range of biological applications, including ortholog identification, estimating gene duplication times, and rooting and correcting gene trees. While reconciliation for binary trees is a tractable and well studied problem, there are no algorithms for reconciliation with non-binary species trees. Yet a striking proportion of species trees are non-binary. For example, 64% of branch points in the NCBI taxonomy have three or more children. When applied to non-binary species trees, current algorithms overestimate the number of duplications because they cannot distinguish between duplication and incomplete lineage sorting. We present the first algorithms for reconciling binary gene trees with non-binary species trees under a duplication-loss parsimony model. Our algorithms utilize an efficient mapping from gene to species trees to infer the minimum number of duplications in O(|VG| · (kS + hS)) time, where |VG| is the number of nodes in the gene tree, hS is the height of the species tree and kS is the size of its largest polytomy. We present a dynamic programming algorithm which also minimizes the total number of losses. Although this algorithm is exponential in the size of the largest polytomy, it performs well in practice for polytomies with outdegree of 12 or less. We also present a heuristic which estimates the minimal number of losses in polynomial time. In empirical tests, this algorithm finds an optimal loss history 99% of the time. Our algorithms have been implemented in Notung, a robust, production quality, tree-fitting program, which provides a graphical user interface for exploratory analysis and also supports automated, high-throughput analysis of large data sets. PMID:18808330
Non-binary or genderqueer genders.
Richards, Christina; Bouman, Walter Pierre; Seal, Leighton; Barker, Meg John; Nieder, Timo O; T'Sjoen, Guy
2016-01-01
Some people have a gender which is neither male nor female and may identify as both male and female at one time, as different genders at different times, as no gender at all, or dispute the very idea of only two genders. The umbrella terms for such genders are 'genderqueer' or 'non-binary' genders. Such gender identities outside of the binary of female and male are increasingly being recognized in legal, medical and psychological systems and diagnostic classifications in line with the emerging presence and advocacy of these groups of people. Population-based studies show a small percentage--but a sizable proportion in terms of raw numbers--of people who identify as non-binary. While such genders have been extant historically and globally, they remain marginalized, and as such--while not being disorders or pathological in themselves--people with such genders remain at risk of victimization and of minority or marginalization stress as a result of discrimination. This paper therefore reviews the limited literature on this field and considers ways in which (mental) health professionals may assist the people with genderqueer and non-binary gender identities and/or expressions they may see in their practice. Treatment options and associated risks are discussed. PMID:26753630
Advanced GF(3^{2}) nonbinary LDPC coded modulation with non-uniform 9-QAM outperforming star 8-QAM.
Liu, Tao; Lin, Changyu; Djordjevic, Ivan B
2016-06-27
In this paper, we first describe a 9-symbol non-uniform signaling scheme based on Huffman code, in which different symbols are transmitted with different probabilities. By using the Huffman procedure, prefix code is designed to approach the optimal performance. Then, we introduce an algorithm to determine the optimal signal constellation sets for our proposed non-uniform scheme with the criterion of maximizing constellation figure of merit (CFM). The proposed nonuniform polarization multiplexed signaling 9-QAM scheme has the same spectral efficiency as the conventional 8-QAM. Additionally, we propose a specially designed GF(3^{2}) nonbinary quasi-cyclic LDPC code for the coded modulation system based on the 9-QAM non-uniform scheme. Further, we study the efficiency of our proposed non-uniform 9-QAM, combined with nonbinary LDPC coding, and demonstrate by Monte Carlo simulation that the proposed GF(2^{3}) nonbinary LDPC coded 9-QAM scheme outperforms nonbinary LDPC coded uniform 8-QAM by at least 0.8dB. PMID:27410549
Experimental study of non-binary LDPC coding for long-haul coherent optical QPSK transmissions.
Zhang, Shaoliang; Arabaci, Murat; Yaman, Fatih; Djordjevic, Ivan B; Xu, Lei; Wang, Ting; Inada, Yoshihisa; Ogata, Takaaki; Aoki, Yasuhiro
2011-09-26
The performance of rate-0.8 4-ary LDPC code has been studied in a 50 GHz-spaced 40 Gb/s DWDM system with PDM-QPSK modulation. The net effective coding gain of 10 dB is obtained at BER of 10(-6). With the aid of time-interleaving polarization multiplexing and MAP detection, 10,560 km transmission over legacy dispersion managed fiber is achieved without any countable errors. The proposed nonbinary quasi-cyclic LDPC code achieves an uncoded BER threshold at 4×10(-2). Potential issues like phase ambiguity and coding length are also discussed when implementing LDPC in current coherent optical systems. PMID:21996844
Towards Noncommutative Topological Quantum Field Theory - Hodge theory for cyclic cohomology
NASA Astrophysics Data System (ADS)
Zois, I. P.
2014-03-01
Some years ago we initiated a program to define Noncommutative Topological Quantum Field Theory (see [1]). The motivation came both from physics and mathematics: On the one hand, as far as physics is concerned, following the well-known holography principle of 't Hooft (which in turn appears essentially as a generalisation of the Hawking formula for black hole entropy), quantum gravity should be a topological quantum field theory. On the other hand as far as mathematics is concerned, the motivation came from the idea to replace the moduli space of flat connections with the Gabai moduli space of codim-1 taut foliations for 3 dim manifolds. In most cases the later is finite and much better behaved and one might use it to define some version of Donaldson-Floer homology which, hopefully, would be easier to compute. The use of foliations brings noncommutative geometry techniques immediately into the game. The basic tools are two: Cyclic cohomology of the corresponding foliation C*-algebra and the so called "tangential cohomology" of the foliation. A necessary step towards this goal is to develop some sort of Hodge theory both for cyclic (and Hochschild) cohomology and for tangential cohomology. Here we present a method to develop a Hodge theory for cyclic and Hochschild cohomology for the corresponding C*-algebra of a foliation.
Quantum codes from cyclic codes over F_q+uF_q+vF_q+uvF_q
NASA Astrophysics Data System (ADS)
Ashraf, Mohammad; Mohammad, Ghulam
2016-07-01
In this paper, we study quantum codes over F_q from cyclic codes over F_q+uF_q+vF_q+uvF_q, where u^2=u,~v^2=v,~uv=vu,~q=p^m , and p is an odd prime. We give the structure of cyclic codes over F_q+uF_q+vF_q+uvF_q and obtain self-orthogonal codes over F_q as Gray images of linear and cyclic codes over F_q+uF_q+vF_q+uvF_q . In particular, we decompose a cyclic code over F_q+uF_q+vF_q+uvF_q into four cyclic codes over F_q to determine the parameters of the corresponding quantum code.
Creation of particles in a cyclic universe driven by loop quantum cosmology
NASA Astrophysics Data System (ADS)
Tavakoli, Yaser; Fabris, Júlio C.
2015-05-01
We consider an isotropic and homogeneous universe in loop quantum cosmology (LQC). We assume that the matter content of the universe is dominated by dust matter in early time and a phantom matter at late time which constitutes the dark energy component. The quantum gravity modifications to the Friedmann equation in this model indicate that the classical big bang singularity and the future big rip singularity are resolved and are replaced by quantum bounce. It turns out that the big bounce and recollapse in the herein model contribute to a cyclic scenario for the universe. We then study the quantum theory of a massive, nonminimally coupled scalar field undergoing cosmological evolution from primordial bounce towards the late time bounce. In particular, we solve the Klein-Gordon equation for the scalar field in the primordial and late time regions, in order to investigate particle production phenomena at late time. By computing the energy density of created particles at late time, we show that this density is negligible in comparison to the quantum background density at Planck era. This indicates that the effects of quantum particle production do not influence the future bounce.
Error Correction using Quantum Quasi-Cyclic Low-Density Parity-Check(LDPC) Codes
NASA Astrophysics Data System (ADS)
Jing, Lin; Brun, Todd; Quantum Research Team
Quasi-cyclic LDPC codes can approach the Shannon capacity and have efficient decoders. Manabu Hagiwara et al., 2007 presented a method to calculate parity check matrices with high girth. Two distinct, orthogonal matrices Hc and Hd are used. Using submatrices obtained from Hc and Hd by deleting rows, we can alter the code rate. The submatrix of Hc is used to correct Pauli X errors, and the submatrix of Hd to correct Pauli Z errors. We simulated this system for depolarizing noise on USC's High Performance Computing Cluster, and obtained the block error rate (BER) as a function of the error weight and code rate. From the rates of uncorrectable errors under different error weights we can extrapolate the BER to any small error probability. Our results show that this code family can perform reasonably well even at high code rates, thus considerably reducing the overhead compared to concatenated and surface codes. This makes these codes promising as storage blocks in fault-tolerant quantum computation. Error Correction using Quantum Quasi-Cyclic Low-Density Parity-Check(LDPC) Codes.
Osipovich, Nikolai P; Poznyak, Sergei K; Lesnyak, Vladimir; Gaponik, Nikolai
2016-04-21
The application of electrochemical methods for the characterization of colloidal quantum dots (QDs) attracts considerable attention as these methods may allow for monitoring of some crucial parameters, such as energetic levels of conduction and valence bands as well as surface traps and ligands under real conditions of colloidal solution. In the present work we extend the applications of cyclic voltammetry (CV) to in situ monitoring of degradation processes of water-soluble CdTe QDs. This degradation occurs under lowering of pH to the values around 5, i.e. under conditions relevant to bioimaging applications of these QDs, and is accompanied by pronounced changes of their photoluminescence. Observed correlations between characteristic features of CV diagrams and the fluorescence spectra allowed us to propose mechanisms responsible for evolution of the photoluminescence properties as well as degradation pathway of CdTe QDs at low pH. PMID:27025663
Big-bounce cosmology from quantum gravity: The case of a cyclical Bianchi I universe
NASA Astrophysics Data System (ADS)
Moriconi, Riccardo; Montani, Giovanni; Capozziello, Salvatore
2016-07-01
We analyze the classical and quantum dynamics of a Bianchi I model in the presence of a small negative cosmological constant characterizing its evolution in term of the dust-time dualism. We demonstrate that in a canonical metric approach, the cosmological singularity is removed in correspondence to a positive defined value of the dust energy density. Furthermore, the quantum big bounce is connected to the Universe's turning point via a well-defined semiclassical limit. Then we can reliably infer that the proposed scenario is compatible with a cyclical universe picture. We also show how, when the contribution of the dust energy density is sufficiently high, the proposed scenario can be extended to the Bianchi IX cosmology and therefore how it can be regarded as a paradigm for the generic cosmological model. Finally, we investigate the origin of the observed cutoff on the cosmological dynamics, demonstrating how the big-bounce evolution can be mimicked by the same semiclassical scenario, where the negative cosmological constant is replaced via a polymer discretization of the Universe's volume. A direct proportionality law between these two parameters is then established.
NASA Astrophysics Data System (ADS)
Wu, Lian-Ao
1994-12-01
It is shown that the cyclic evolution posed by Aharonov and Anandan [Phys. Rev. Lett. 58, 1593 (1987)] universally exists in any quantum system: cyclic evolution occurs for special initial wave functions, whatever the concrete form of the Hamiltonian. The above results are illustrated and some specific geometric phases are given.
Where Kinsey, Christ, and Tila Tequila meet: discourse and the sexual (non)-binary.
Callis, April S
2014-01-01
Drawing on 80 interviews and 17 months of participant observation in Lexington, Kentucky, this article details how individuals drew on three areas of national and local discourse to conceptualize sexuality. Media, popular science, and religious discourses can be viewed as portraying sexuality bifocally--as both a binary of heterosexual/homosexual and as a non-binary that encompasses fluidity. However, individuals in Lexington drew on each of these areas of discourse differently. Religion was thought to produce a binary vision of sexuality, whereas popular science accounts were understood as both binary and not. The media was understood as portraying non-binary identities that were not viable, thus strengthening the sexual binary. These differing points of view led identities such as bisexual and queer to lack cultural intelligibility. PMID:25089615
Lin, Changyu; Zou, Ding; Liu, Tao; Djordjevic, Ivan B
2016-08-01
A mutual information inspired nonbinary coded modulation design with non-uniform shaping is proposed. Instead of traditional power of two signal constellation sizes, we design 5-QAM, 7-QAM and 9-QAM constellations, which can be used in adaptive optical networks. The non-uniform shaping and LDPC code rate are jointly considered in the design, which results in a better performance scheme for the same SNR values. The matched nonbinary (NB) LDPC code is used for this scheme, which further improves the coding gain and the overall performance. We analyze both coding performance and system SNR performance. We show that the proposed NB LDPC-coded 9-QAM has more than 2dB gain in symbol SNR compared to traditional LDPC-coded star-8-QAM. On the other hand, the proposed NB LDPC-coded 5-QAM and 7-QAM have even better performance than LDPC-coded QPSK. PMID:27505775
On the correspondence of semiclassical and quantum phases in cyclic evolutions
Benedict, M.G. ); Schleich, W. )
1993-03-01
Based on the exactly solvable case of a harmonic oscillator, the authors show that the direct correspondence between the Bohr-Sommerfeld phase of semiclassical quantum mechanics and the topological phase of Aharonov and Anandan is restricted to the case of a coherent state. For other Gaussian wave packets the geometric quantum phase strongly depends on the amount of squeezing. 12 refs.
NASA Astrophysics Data System (ADS)
Golub, P.; Doroshenko, I.; Pogorelov, V.
2014-05-01
The specific peculiarities of alcohols such as heightened viscosity, boiling temperature and surface tension can be explained by the capability of their molecules to form relatively stable associates named clusters due to hydrogen bonding. In present work the stability of different chain-like and cyclic clusters of methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol and 1-hexanol was investigated by means of quantum-chemical simulation and particular by recently developed DFT exchange-correlation functional M06-2X. The relative stability of the cluster structure was evaluated by the total energy per molecule at low temperatures (where all alcohols exist in solid state) and by the changing of the free Gibbs energy upon cluster formation at the room temperature. For the verification of revealed results the conformity of calculated IR spectra of the most stable cluster structures with the experimental IR spectra at different temperatures was analyzed.
Svirskii, M.S.
1985-09-10
Oscillations with a period equal to the normal or superconducting flux quantum occur in the current density and the orbital parts of the energy and the magnetic moment in cyclic systems. Transitions between these regimes can be induced by changing the number of electrons or by switching between states with different energies.
Stolzer, Maureen; Lai, Han; Xu, Minli; Sathaye, Deepa; Vernot, Benjamin; Durand, Dannie
2012-01-01
Motivation: Gene duplication (D), transfer (T), loss (L) and incomplete lineage sorting (I) are crucial to the evolution of gene families and the emergence of novel functions. The history of these events can be inferred via comparison of gene and species trees, a process called reconciliation, yet current reconciliation algorithms model only a subset of these evolutionary processes. Results: We present an algorithm to reconcile a binary gene tree with a nonbinary species tree under a DTLI parsimony criterion. This is the first reconciliation algorithm to capture all four evolutionary processes driving tree incongruence and the first to reconcile non-binary species trees with a transfer model. Our algorithm infers all optimal solutions and reports complete, temporally feasible event histories, giving the gene and species lineages in which each event occurred. It is fixed-parameter tractable, with polytime complexity when the maximum species outdegree is fixed. Application of our algorithms to prokaryotic and eukaryotic data show that use of an incomplete event model has substantial impact on the events inferred and resulting biological conclusions. Availability: Our algorithms have been implemented in Notung, a freely available phylogenetic reconciliation software package, available at http://www.cs.cmu.edu/~durand/Notung. Contact: mstolzer@andrew.cmu.edu PMID:22962460
Cyclic Polyynes as Examples of the Quantum Mechanical Particle on a Ring
ERIC Educational Resources Information Center
Anderson, Bruce D.
2012-01-01
Many quantum mechanical models are discussed as part of the undergraduate physical chemistry course to help students understand the connection between eigenvalue expressions and spectroscopy. Typical examples covered include the particle in a box, the harmonic oscillator, the rigid rotor, and the hydrogen atom. This article demonstrates that…
Quantum routing of single photons with a cyclic three-level system.
Zhou, Lan; Yang, Li-Ping; Li, Yong; Sun, C P
2013-09-01
We propose an experimentally accessible single-photon routing scheme using a △-type three-level atom embedded in quantum multichannels composed of coupled-resonator waveguides. Via the on-demand classical field being applied to the atom, the router can extract a single photon from the incident channel, and then redirect it into another. The efficient function of the perfect reflection of the single-photon signal in the incident channel is rooted in the coherent resonance and the existence of photonic bound states. PMID:25166667
Competitive lithium solvation of linear and cyclic carbonates from quantum chemistry
Kent, Paul R. C.; Ganesh, Panchapakesan; Borodin, Oleg; Olguin, Marco; Allen, Joshua L.; Henderson, Wesley A.
2015-11-17
The composition of the lithium cation (Li+) solvation shell in mixed linear and cyclic carbonate-based electrolytes has been re-examined using Born–Oppenheimer molecular dynamics (BOMD) as a function of salt concentration and cluster calculations with ethylene carbonate:dimethyl carbonate (EC:DMC)–LiPF6 as a model system. A coordination preference for EC over DMC to a Li+ was found at low salt concentrations, while a slightly higher preference for DMC over EC was found at high salt concentrations. Analysis of the relative binding energies of the (EC)n(DMC)m–Li+ and (EC)n(DMC)m–LiPF6 solvates in the gas-phase and for an implicit solvent (as a function of the solvent dielectricmore » constant) indicated that the DMC-containing Li+ solvates were stabilized relative to (EC4)–Li+ and (EC)3–LiPF6 by immersing them in the implicit solvent. Such stabilization was more pronounced in the implicit solvents with a high dielectric constant. Results from previous Raman and IR experiments were reanalyzed and reconciled by correcting them for changes of the Raman activities, IR intensities and band shifts for the solvents which occur upon Li+ coordination. After these correction factors were applied to the results of BOMD simulations, the composition of the Li+ solvation shell from the BOMD simulations was found to agree well with the solvation numbers extracted from Raman experiments. Finally, the mechanism of the Li+ diffusion in the dilute (EC:DMC)LiPF6 mixed solvent electrolyte was studied using the BOMD simulations.« less
Competitive lithium solvation of linear and cyclic carbonates from quantum chemistry.
Borodin, Oleg; Olguin, Marco; Ganesh, P; Kent, Paul R C; Allen, Joshua L; Henderson, Wesley A
2016-01-01
The composition of the lithium cation (Li(+)) solvation shell in mixed linear and cyclic carbonate-based electrolytes has been re-examined using Born-Oppenheimer molecular dynamics (BOMD) as a function of salt concentration and cluster calculations with ethylene carbonate:dimethyl carbonate (EC:DMC)-LiPF6 as a model system. A coordination preference for EC over DMC to a Li(+) was found at low salt concentrations, while a slightly higher preference for DMC over EC was found at high salt concentrations. Analysis of the relative binding energies of the (EC)n(DMC)m-Li(+) and (EC)n(DMC)m-LiPF6 solvates in the gas-phase and for an implicit solvent (as a function of the solvent dielectric constant) indicated that the DMC-containing Li(+) solvates were stabilized relative to (EC4)-Li(+) and (EC)3-LiPF6 by immersing them in the implicit solvent. Such stabilization was more pronounced in the implicit solvents with a high dielectric constant. Results from previous Raman and IR experiments were reanalyzed and reconciled by correcting them for changes of the Raman activities, IR intensities and band shifts for the solvents which occur upon Li(+) coordination. After these correction factors were applied to the results of BOMD simulations, the composition of the Li(+) solvation shell from the BOMD simulations was found to agree well with the solvation numbers extracted from Raman experiments. Finally, the mechanism of the Li(+) diffusion in the dilute (EC:DMC)LiPF6 mixed solvent electrolyte was studied using the BOMD simulations. PMID:26601903
Competitive lithium solvation of linear and cyclic carbonates from quantum chemistry
Kent, Paul R. C.; Ganesh, Panchapakesan; Borodin, Oleg; Olguin, Marco; Allen, Joshua L.; Henderson, Wesley A.
2015-11-17
The composition of the lithium cation (Li+) solvation shell in mixed linear and cyclic carbonate-based electrolytes has been re-examined using Born–Oppenheimer molecular dynamics (BOMD) as a function of salt concentration and cluster calculations with ethylene carbonate:dimethyl carbonate (EC:DMC)–LiPF_{6} as a model system. A coordination preference for EC over DMC to a Li+ was found at low salt concentrations, while a slightly higher preference for DMC over EC was found at high salt concentrations. Analysis of the relative binding energies of the (EC)_{n}(DMC)_{m}–Li+ and (EC)_{n}(DMC)_{m}–LiPF_{6} solvates in the gas-phase and for an implicit solvent (as a function of the solvent dielectric constant) indicated that the DMC-containing Li+ solvates were stabilized relative to (EC_{4})–Li+ and (EC)_{3}–LiPF_{6} by immersing them in the implicit solvent. Such stabilization was more pronounced in the implicit solvents with a high dielectric constant. Results from previous Raman and IR experiments were reanalyzed and reconciled by correcting them for changes of the Raman activities, IR intensities and band shifts for the solvents which occur upon Li+ coordination. After these correction factors were applied to the results of BOMD simulations, the composition of the Li+ solvation shell from the BOMD simulations was found to agree well with the solvation numbers extracted from Raman experiments. Finally, the mechanism of the Li+ diffusion in the dilute (EC:DMC)LiPF_{6} mixed solvent electrolyte was studied using the BOMD simulations.
NASA Astrophysics Data System (ADS)
Marosek, Konrad; Da¸browski, Mariusz P.; Balcerzak, Adam
2016-09-01
Using the idea of regularization of singularities due to the variability of the fundamental constants in cosmology we study the cyclic universe models. We find two models of oscillating and non-singular mass density and pressure (`non-singular' bounce) regularized by varying gravitational constant G despite the scale factor evolution is oscillating and having sharp turning points (`singular' bounce). Both violating (big-bang) and non-violating (phantom) null energy condition models appear. Then, we extend this idea on to the multiverse containing cyclic individual universes with either growing or decreasing entropy though leaving the net entropy constant. In order to get an insight into the key idea, we consider the doubleverse with the same geometrical evolution of the two `parallel' universes with their physical evolution [physical coupling constants c(t) and G(t)] being different. An interesting point is that there is a possibility to exchange the universes at the point of maximum expansion - the fact which was already noticed in quantum cosmology. Similar scenario is also possible within the framework of Brans-Dicke theory where varying G(t) is replaced by the dynamical Brans-Dicke field φ(t) though these theories are slightly different.
NASA Astrophysics Data System (ADS)
Wang, Liming; Qiao, Yaojun; Yu, Qian; Zhang, Wenbo
2016-04-01
We introduce a watermark non-binary low-density parity check code (NB-LDPC) scheme, which can estimate the time-varying noise variance by using prior information of watermark symbols, to improve the performance of NB-LDPC codes. And compared with the prior-art counterpart, the watermark scheme can bring about 0.25 dB improvement in net coding gain (NCG) at bit error rate (BER) of 1e-6 and 36.8-81% reduction of the iteration numbers. Obviously, the proposed scheme shows great potential in terms of error correction performance and decoding efficiency.
FPGA implementation of concatenated non-binary QC-LDPC codes for high-speed optical transport.
Zou, Ding; Djordjevic, Ivan B
2015-06-01
In this paper, we propose a soft-decision-based FEC scheme that is the concatenation of a non-binary LDPC code and hard-decision FEC code. The proposed NB-LDPC + RS with overhead of 27.06% provides a superior NCG of 11.9dB at a post-FEC BER of 10^{-15}. As a result, the proposed NB-LDPC codes represent the strong FEC candidate of soft-decision FEC for beyond 100Gb/s optical transmission systems. PMID:26072810
Non-binary coded modulation for FMF-based coherent optical transport networks
NASA Astrophysics Data System (ADS)
Lin, Changyu
The Internet has fundamentally changed the way of modern communication. Current trends indicate that high-capacity demands are not going to be saturated anytime soon. From Shannon's theory, we know that information capacity is a logarithmic function of signal-to-noise ratio (SNR), but a linear function of the number of dimensions. Ideally, we can increase the capacity by increasing the launch power, however, due to the nonlinear characteristics of silica optical fibers that imposes a constraint on the maximum achievable optical-signal-to-noise ratio (OSNR). So there exists a nonlinear capacity limit on the standard single mode fiber (SSMF). In order to satisfy never ending capacity demands, there are several attempts to employ additional degrees of freedom in transmission system, such as few-mode fibers (FMFs), which can dramatically improve the spectral efficiency. On the other hand, for the given physical links and network equipment, an effective solution to relax the OSNR requirement is based on forward error correction (FEC), as the response to the demands of high speed reliable transmission. In this dissertation, we first discuss the model of FMF with nonlinear effects considered. Secondly, we simulate the FMF based OFDM system with various compensation and modulation schemes. Thirdly, we propose tandem-turbo-product nonbinary byte-interleaved coded modulation (BICM) for next-generation high-speed optical transmission systems. Fourthly, we study the Q factor and mutual information as threshold in BICM scheme. Lastly, an experimental study of the limits of nonlinearity compensation with digital signal processing has been conducted.
Zhang, Yequn; Arabaci, Murat; Djordjevic, Ivan B
2012-04-01
Leveraging the advanced coherent optical communication technologies, this paper explores the feasibility of using four-dimensional (4D) nonbinary LDPC-coded modulation (4D-NB-LDPC-CM) schemes for long-haul transmission in future optical transport networks. In contrast to our previous works on 4D-NB-LDPC-CM which considered amplified spontaneous emission (ASE) noise as the dominant impairment, this paper undertakes transmission in a more realistic optical fiber transmission environment, taking into account impairments due to dispersion effects, nonlinear phase noise, Kerr nonlinearities, and stimulated Raman scattering in addition to ASE noise. We first reveal the advantages of using 4D modulation formats in LDPC-coded modulation instead of conventional two-dimensional (2D) modulation formats used with polarization-division multiplexing (PDM). Then we demonstrate that 4D LDPC-coded modulation schemes with nonbinary LDPC component codes significantly outperform not only their conventional PDM-2D counterparts but also the corresponding 4D bit-interleaved LDPC-coded modulation (4D-BI-LDPC-CM) schemes, which employ binary LDPC codes as component codes. We also show that the transmission reach improvement offered by the 4D-NB-LDPC-CM over 4D-BI-LDPC-CM increases as the underlying constellation size and hence the spectral efficiency of transmission increases. Our results suggest that 4D-NB-LDPC-CM can be an excellent candidate for long-haul transmission in next-generation optical networks. PMID:22513641
Arabaci, Murat; Djordjevic, Ivan B; Saunders, Ross; Marcoccia, Roberto M
2010-02-01
In order to achieve high-speed transmission over optical transport networks (OTNs) and maximize its throughput, we propose using a rate-adaptive polarization-multiplexed coded multilevel modulation with coherent detection based on component non-binary quasi-cyclic (QC) LDPC codes. Compared to prior-art bit-interleaved LDPC-coded modulation (BI-LDPC-CM) scheme, the proposed non-binary LDPC-coded modulation (NB-LDPC-CM) scheme not only reduces latency due to symbol- instead of bit-level processing but also provides either impressive reduction in computational complexity or striking improvements in coding gain depending on the constellation size. As the paper presents, compared to its prior-art binary counterpart, the proposed NB-LDPC-CM scheme addresses the needs of future OTNs, which are achieving the target BER performance and providing maximum possible throughput both over the entire lifetime of the OTN, better. PMID:20174010
Aseev, Oleg; Perez, Marta A S; Rothlisberger, Ursula; Rizzo, Thomas R
2015-07-01
Collision-induced dissociation (CID) is a key technique used in mass spectrometry-based peptide sequencing. Collisionally activated peptides undergo statistical dissociation, forming a series of backbone fragment ions that reflect their amino acid (AA) sequence. Some of these fragments may experience a "head-to-tail" cyclization, which after proton migration, can lead to the cyclic structure opening in a different place than the initially formed bond. This process leads to AA sequence scrambling that may hinder sequencing of the initial peptide. Here we combine cryogenic ion spectroscopy and ab initio molecular dynamics simulations to isolate and characterize the precise structures of key intermediates in the scrambling process. The most stable peptide fragments show intriguing symmetric cyclic structures in which the proton is situated on a C2 symmetry axis and forms exceptionally short H-bonds (1.20 Å) with two backbone oxygens. Other nonsymmetric cyclic structures also exist, one of which is protonated on the amide nitrogen, where ring opening is likely to occur. PMID:26266729
Rotational properties of the binary and non-binary populations in the trans-Neptunian belt
NASA Astrophysics Data System (ADS)
Thirouin, A.; Noll, K. S.; Ortiz, J. L.; Morales, N.
2014-09-01
We present results for the short-term variability of binary trans-Neptunian objects (BTNOs). We performed CCD photometric observations using the 3.58 m Telescopio Nazionale Galileo (TNG), the 1.5 m Sierra Nevada Observatory (OSN) telescope, and the 1.23 m Centro Astronómico Hispano Alemán (CAHA) telescope at Calar Alto Observatory. We present results based on five years of observations and report the short-term variability of six BTNOs. Our sample contains three classical objects: (174567) 2003 MW12, or Varda, (120347) 2004 SB60, or Salacia, and 2002 VT130; one detached disk object: (229762) 2007 UK126; and two resonant objects: (341520) 2007 TY430 and (38628) 2000 EB173, or Huya. For each target, possible rotational periods and/or photometric amplitudes are reported. We also derived some physical properties from their light curves, such as density, primary and secondary sizes, and albedo. We compiled and analyzed a vast light curve database for TNOs including centaurs to determine the light-curve amplitude and spin frequency distributions for the binary and non-binary populations. The mean rotational periods, from the Maxwellian fits to the frequency distributions, are 8.63 ± 0.52 h for the entire sample, 8.37 ± 0.58 h for the sample without the binary population, and 10.11 ± 1.19 h for the binary population alone. Because the centaurs are collisionally more evolved, their rotational periods might not be so primordial. We computed a mean rotational period, from the Maxwellian fit, of 8.86 ± 0.58 h for the sample without the centaur population, and of 8.64 ± 0.67 h considering a sample without the binary and the centaur populations. According to this analysis, regular TNOs spin faster than binaries, which is compatible with the tidal interaction of the binaries. Finally, we examined possible formation models for several systems studied in this work and by our team in previous papers. Appendix A is available in electronic form at http
Dyekjaer, Jane; Rasmussen, Kjeld; Jónsdóttir, Svava
2002-09-01
Values for nine descriptors for QSPR (quantitative structure-property relationships) modeling of physical properties of 96 alkanes, alcohols, ethers, diols, triols and cyclic alkanes and alcohols in conjunction with the program Codessa are presented. The descriptors are Boltzmann-averaged by selection of the most relevant conformers out of a set of possible molecular conformers generated by a systematic scheme presented in this paper. Six of these descriptors are calculated with molecular mechanics and three with quantum chemical methods. Especially interesting descriptors are the relative van der Waals energies and the molecular polarizabilities, which correlate very well with boiling points. Five more simple descriptors that only depend on the molecular constitutional formula are also discussed briefly. PMID:12415333
Mereshchenko, Andrey S; Ivanov, Alexey V; Baranovskii, Viktor I; Rodina, Ludmila L
2015-01-01
Summary The 1,3-dipolar cycloaddition of acyclic 2-diazo-1,3-dicarbonyl compounds (DDC) and thioketones preferably occurs with Z,E-conformers and leads to the formation of transient thiocarbonyl ylides in two stages. The thermodynamically favorable further transformation of C=S ylides bearing at least one acyl group is identified as the 1,5-electrocyclization into 1,3-oxathioles. However, in the case of diazomalonates, the dominating process is 1,3-cyclization into thiiranes followed by their spontaneous desulfurization yielding the corresponding alkenes. Finally, carbocyclic diazodiketones are much less reactive under similar conditions due to the locked cyclic structure and are unfavorable for the 1,3-dipolar cycloaddition due to the Z,Z-conformation of the diazo molecule. This structure results in high, positive values of the Gibbs free energy change for the first stage of the cycloaddition process. PMID:25977725
Ananyev, Gennady; Gates, Colin; Dismukes, G Charles
2016-09-01
We have measured flash-induced oxygen quantum yields (O2-QYs) and primary charge separation (Chl variable fluorescence yield, Fv/Fm) in vivo among phylogenetically diverse microalgae and cyanobacteria. Higher O2-QYs can be attained in cells by releasing constraints on charge transfer at the Photosystem II (PSII) acceptor side by adding membrane-permeable benzoquinone (BQ) derivatives that oxidize plastosemiquinone QB(-) and QBH2. This method allows uncoupling PSII turnover from its natural regulation in living cells, without artifacts of isolating PSII complexes. This approach reveals different extents of regulation across species, controlled at the QB(-) acceptor site. Arthrospira maxima is confirmed as the most efficient PSII-WOC (water oxidizing complex) and exhibits the least regulation of flux. Thermosynechococcus elongatus exhibits an O2-QY of 30%, suggesting strong downregulation. WOC cycle simulations with the most accurate model (VZAD) show that a light-driven backward transition (net addition of an electron to the WOC, distinct from recombination) occurs in up to 25% of native PSIIs in the S2 and S3 states, while adding BQ prevents backward transitions and increases the lifetime of S2 and S3 by 10-fold. Backward transitions occur in PSIIs that have plastosemiquinone radicals in the QB site and are postulated to be physiologically regulated pathways for storing light energy as proton gradient through direct PSII-cyclic electron flow (PSII-CEF). PSII-CEF is independent of classical PSI/cyt-b6f-CEF and provides an alternative proton translocation pathway for energy conversion. PSII-CEF enables variable fluxes between linear and cyclic electron pathways, thus accommodating species-dependent needs for redox and ion-gradient energy sources powered by a single photosystem. PMID:27117512
Ansara, Y Gavriel
2015-10-01
Recent Australian legislative and policy changes can benefit people of trans and/or non-binary experience (e.g. men assigned female with stereotypically 'female' bodies, women assigned male with stereotypically 'male' bodies, and people who identify as genderqueer, agender [having no gender], bi-gender [having two genders] or another gender option). These populations often experience cisgenderism, which previous research defined as 'the ideology that invalidates people's own understanding of their genders and bodies'. Some documented forms of cisgenderism include pathologising (treating people's genders and bodies as disordered) and misgendering (disregarding people's own understanding and classifications of their genders and bodies). This system of classifying people's lived experiences of gender and body invalidation is called the cisgenderism framework. Applying the cisgenderism framework in the ageing and aged care sector can enhance service providers' ability to meet the needs of older people of trans and/or non-binary experience. PMID:26525440
Allen, Joshua L.; Borodin, Oleg; Seo, D. M.; Henderson, Wesley A.
2014-12-01
Combined computational/Raman spectroscopic analyses of ethylene carbonate (EC) and propylene carbonate (PC) solvation interactions with lithium salts are reported. It is proposed that previously reported Raman analyses of (EC)n-LiX mixtures have utilized faulty assumptions. In the present studies, density functional theory (DFT) calculations have provided corrections in terms of both the scaling factors for the solvent's Raman band intensity variations and information about band overlap. By accounting for these factors, the solvation numbers obtained from two different EC solvent bands are in excellent agreement with one another. The same analysis for PC, however, was found to be quite challenging. Commercially available PC is a racemic mixture of (S)- and (R)-PC isomers. Based upon the quantum chemistry calculations, each of these solvent isomers may exist as multiple conformers due to a low energy barrier for ring inversion, making deconvolution of the Raman bands daunting and inherently prone to significant error. Thus, Raman spectroscopy is able to accurately determine the extent of the EC...Li+ cation solvation interactions using the provided methodology, but a similar analysis of PC...Li+ cation solvation results in a significant underestimation of the actual solvation numbers.
ERIC Educational Resources Information Center
Evans, Dennis H.; And Others
1983-01-01
Cyclic voltammetry is a simple experiment that has become popular in chemical research because it can provide useful information about redox reactions in a form which is easily obtained and interpreted. Discusses principles of the method and illustrates its use in the study of four electrode reactions. (Author/JN)
NASA Astrophysics Data System (ADS)
Almog, Assaf; Garlaschelli, Diego
2014-09-01
The dynamics of complex systems, from financial markets to the brain, can be monitored in terms of multiple time series of activity of the constituent units, such as stocks or neurons, respectively. While the main focus of time series analysis is on the magnitude of temporal increments, a significant piece of information is encoded into the binary projection (i.e. the sign) of such increments. In this paper we provide further evidence of this by showing strong nonlinear relations between binary and non-binary properties of financial time series. These relations are a novel quantification of the fact that extreme price increments occur more often when most stocks move in the same direction. We then introduce an information-theoretic approach to the analysis of the binary signature of single and multiple time series. Through the definition of maximum-entropy ensembles of binary matrices and their mapping to spin models in statistical physics, we quantify the information encoded into the simplest binary properties of real time series and identify the most informative property given a set of measurements. Our formalism is able to accurately replicate, and mathematically characterize, the observed binary/non-binary relations. We also obtain a phase diagram allowing us to identify, based only on the instantaneous aggregate return of a set of multiple time series, a regime where the so-called ‘market mode’ has an optimal interpretation in terms of collective (endogenous) effects, a regime where it is parsimoniously explained by pure noise, and a regime where it can be regarded as a combination of endogenous and exogenous factors. Our approach allows us to connect spin models, simple stochastic processes, and ensembles of time series inferred from partial information.
Cyclic transformation of orbital angular momentum modes
NASA Astrophysics Data System (ADS)
Schlederer, Florian; Krenn, Mario; Fickler, Robert; Malik, Mehul; Zeilinger, Anton
2016-04-01
The spatial modes of photons are one realization of a QuDit, a quantum system that is described in a D-dimensional Hilbert space. In order to perform quantum information tasks with QuDits, a general class of D-dimensional unitary transformations is needed. Among these, cyclic transformations are an important special case required in many high-dimensional quantum communication protocols. In this paper, we experimentally demonstrate a cyclic transformation in the high-dimensional space of photonic orbital angular momentum (OAM). Using simple linear optical components, we show a successful four-fold cyclic transformation of OAM modes. Interestingly, our experimental setup was found by a computer algorithm. In addition to the four-cyclic transformation, the algorithm also found extensions to higher-dimensional cycles in a hybrid space of OAM and polarization. Besides being useful for quantum cryptography with QuDits, cyclic transformations are key for the experimental production of high-dimensional maximally entangled Bell-states.
Khavani, Mohammad; Izadyar, Mohammad; Housaindokht, Mohammad Reza
2015-10-14
In this article, cyclic peptides (CP) with lipid substituents were theoretically designed. The dynamical behavior of the CP dimers and the cyclic peptide nanotube (CPNT) without lipid substituents in the solution (water and chloroform) during the 50 ns molecular dynamic (MD) simulations has been investigated. As a result, the CP dimers and CPNT in a non-polar solvent are more stable than in a polar solvent and CPNT is a good container for non-polar small molecules such as chloroform. The effect of the lipid substituents on the CP dimers and CPNT has been investigated in the next stage of our studies. Accordingly, these substituents increase the stability of the CP dimers and CPNT, significantly, in polar solvents. MM-PBSA and MM-GBSA calculations confirm that substitution has an important effect on the stability of the CP dimers and CPNT. Finally, the dynamical behavior of CPNT with lipid substituents in a fully hydrated DMPC bilayer shows the high ability of this structure for molecule transmission across the lipid membrane. This structure is stable enough to be used as a molecular channel. DFT calculations on the CP dimers in the gas phase, water and chloroform, indicate that H-bond formation is the driving force for dimerization. CP dimers are more stable in the gas phase in comparison to in solution. HOMO-LUMO orbital analysis indicates that the interaction of the CP units in the dimer structures is due to the molecular orbital interactions between the NH and CO groups. PMID:26366633
General solution of the cyclic Leibniz rule
NASA Astrophysics Data System (ADS)
Kadoh, Daisuke; Ukita, Naoya
2015-10-01
We study the cyclic Leibniz rule (CLR) which was recently proposed as a new approach to the realization of supersymmetric quantum mechanics on the lattice. The CLR has an infinite number of solutions that give the different definitions of the lattice supersymmetric quantum mechanics. We show the general form of the solution for the naive symmetric difference operator and reveal the differences between the lattice models.
Scale invariant density perturbations from cyclic cosmology
NASA Astrophysics Data System (ADS)
Frampton, Paul Howard
2016-04-01
It is shown how quantum fluctuations of the radiation during the contraction era of a comes back empty (CBE) cyclic cosmology can provide density fluctuations which re-enter the horizon during the subsequent expansion era and at lowest order are scale invariant, in a Harrison-Zel’dovich-Peebles sense. It is necessary to be consistent with observations of large scale structure.
Plant Cyclic Nucleotide Signalling
Martinez-Atienza, Juliana; Van Ingelgem, Carl; Roef, Luc
2007-01-01
The presence of the cyclic nucleotides 3′,5′-cyclic adenyl monophosphate (cAMP) and 3′,5′-cyclic guanyl monophosphate (cGMP) in plants is now generally accepted. In addition, cAMP and cGMP have been implicated in the regulation of important plant processes such as stomatal functioning, monovalent and divalent cation fluxes, chloroplast development, gibberellic acid signalling, pathogen response and gene transcription. However, very little is known regarding the components of cyclic nucleotide signalling in plants. In this addendum, the evidence for specific mechanisms of plant cyclic nucleotide signalling is evaluated and discussed. PMID:19704553
Cyclic phosphonium ionic liquids
Mukhlall, Joshua A; Romeo, Alicia R; Gohdo, Masao; Ramati, Sharon; Berman, Marc; Suarez, Sophia N
2014-01-01
Summary Ionic liquids (ILs) incorporating cyclic phosphonium cations are a novel category of materials. We report here on the synthesis and characterization of four new cyclic phosphonium bis(trifluoromethylsulfonyl)amide ILs with aliphatic and aromatic pendant groups. In addition to the syntheses of these novel materials, we report on a comparison of their properties with their ammonium congeners. These exemplars are slightly less conductive and have slightly smaller self-diffusion coefficients than their cyclic ammonium congeners. PMID:24605146
ERIC Educational Resources Information Center
Adams, Gerald J.; Dial, Micah
1998-01-01
The cyclical nature of mathematics grades was studied for a cohort of elementary school students from a large metropolitan school district in Texas over six years (average cohort size of 8495). The study used an autoregressive integrated moving average (ARIMA) model. Results indicate that grades do exhibit a significant cyclical pattern. (SLD)
ERIC Educational Resources Information Center
Stewart, Greg; Kuntzleman, Thomas S.; Amend, John R.; Collins, Michael J.
2009-01-01
Cyclic voltammetry is an important component of the undergraduate chemical curriculum. Unfortunately, undergraduate students rarely have the opportunity to conduct experiments in cyclic voltammetry owing to the high cost of potentiostats, which are required to control these experiments. By using MicroLab data acquisition interfaces in conjunction…
Genetics Home Reference: cyclic neutropenia
... Understand Genetics Home Health Conditions cyclic neutropenia cyclic neutropenia Enable Javascript to view the expand/collapse boxes. Download PDF Open All Close All Description Cyclic neutropenia is a disorder that causes frequent infections and ...
Whitaker, Charles N.; Zimmermann, Richard E.
1989-01-01
A cyclic control stick of the type used in helicopters for reducing the safety hazards associated with such a mechanism in the event of a crewman being thrown violently into contact with the cyclic control stick resulting from a crash or the like. The cyclic control stick is configured to break away upon the exertion of an impact force which exceeds a predetermined value and/or is exerted for more than a momentary time duration. The cyclic control stick is also configured to be adjustable so as to locate the grip thereof as far away from the crewman as possible for safety reasons without comprising the comfort of the crewman or the use of the control stick, and a crushable pad is provided on the top of the grip for impact energy absorbing purposes.
NASA Astrophysics Data System (ADS)
Yokokawa, M.; Izumi, N.; Naito, K.; Parker, G.; Yamada, T.; Greve, R.
2016-05-01
Boundary waves often form at the interface between ice and fluid flowing adjacent to it, such as ripples under river ice covers, and steps on the bed of supraglacial meltwater channels. They may also be formed by wind, such as the megadunes on the Antarctic ice sheet. Spiral troughs on the polar ice caps of Mars have been interpreted to be cyclic steps formed by katabatic wind blowing over ice. Cyclic steps are relatives of upstream-migrating antidunes. Cyclic step formation on ice is not only a mechanical but also a thermodynamic process. There have been very few studies on the formation of either cyclic steps or upstream-migrating antidunes on ice. In this study, we performed flume experiments to reproduce cyclic steps on ice by flowing water, and found that trains of steps form when the Froude number is larger than unity. The features of those steps allow them to be identified as ice-bed analogs of cyclic steps in alluvial and bedrock rivers. We performed a linear stability analysis and obtained a physical explanation of the formation of upstream-migrating antidunes, i.e., precursors of cyclic steps. We compared the results of experiments with the predictions of the analysis and found the observed steps fall in the range where the analysis predicts interfacial instability. We also found that short antidune-like undulations formed as a precursor to the appearance of well-defined steps. This fact suggests that such antidune-like undulations correspond to the instability predicted by the analysis and are precursors of cyclic steps.
Roland, Christopher D; Li, Hong; Abboud, Khalil A; Wagener, Kenneth B; Veige, Adam S
2016-08-01
Cyclic polymers have dramatically different physical properties compared with those of their equivalent linear counterparts. However, the exploration of cyclic polymers is limited because of the inherent challenges associated with their synthesis. Conjugated linear polyacetylenes are important materials for electrical conductivity, paramagnetic susceptibility, optical nonlinearity, photoconductivity, gas permeability, liquid crystallinity and chain helicity. However, their cyclic analogues are unknown, and therefore the ability to examine how a cyclic topology influences their properties is currently not possible. We have solved this challenge and now report a tungsten catalyst supported by a tetraanionic pincer ligand that can rapidly polymerize alkynes to form conjugated macrocycles in high yield. The catalyst works by tethering the ends of the polymer to the metal centre to overcome the inherent entropic penalty of cyclization. Gel-permeation chromatography, dynamic and static light scattering, viscometry and chemical tests are all consistent with theoretical predictions and provide unambiguous confirmation of a cyclic topology. Access to a wide variety of new cyclic polymers is now possible by simply choosing the appropriate alkyne monomer. PMID:27442285
NASA Astrophysics Data System (ADS)
Roland, Christopher D.; Li, Hong; Abboud, Khalil A.; Wagener, Kenneth B.; Veige, Adam S.
2016-08-01
Cyclic polymers have dramatically different physical properties compared with those of their equivalent linear counterparts. However, the exploration of cyclic polymers is limited because of the inherent challenges associated with their synthesis. Conjugated linear polyacetylenes are important materials for electrical conductivity, paramagnetic susceptibility, optical nonlinearity, photoconductivity, gas permeability, liquid crystallinity and chain helicity. However, their cyclic analogues are unknown, and therefore the ability to examine how a cyclic topology influences their properties is currently not possible. We have solved this challenge and now report a tungsten catalyst supported by a tetraanionic pincer ligand that can rapidly polymerize alkynes to form conjugated macrocycles in high yield. The catalyst works by tethering the ends of the polymer to the metal centre to overcome the inherent entropic penalty of cyclization. Gel-permeation chromatography, dynamic and static light scattering, viscometry and chemical tests are all consistent with theoretical predictions and provide unambiguous confirmation of a cyclic topology. Access to a wide variety of new cyclic polymers is now possible by simply choosing the appropriate alkyne monomer.
Hébuterne, X; Rampal, P
1996-02-10
Cyclic enteral nutrition consists in continuous infusion of nutrients with a pump over a 12 to 14 hour period at night. Different reports have demonstrated that cyclic enteral nutrition is well tolerated in malnourished ambulatory patients. The incidence of pneumonia by inhalation in this type of patients is less than 2%. Excepting patients with major amputation of the small intestine and important functional consequences, the increased infusion rate required by cyclic enteral nutrition does not diminish digestive tract absorption making the technique as effective as continuous 24-hour infusion. The main advantages of the cyclic infusion are the preservation of physiological balance between fasting and feeding, improved physical activity during the day with its beneficial effect on protein-energy metabolism, compatibility with oral nutrition during the day in nutrition reeducation programs, and the psychological impact in patients who are free to move about, further improving tolerance. Finally, cyclic enteral nutrition is adapted to enteral nutrition programs conducted in the patient's homes. PMID:8729381
Cyclic membrane separation process
Bowser, John
2004-04-13
A cyclic process for controlling environmental emissions of volatile organic compounds (VOC) from vapor recovery in storage and dispensing operations of liquids maintains a vacuum in the storage tank ullage. In one of a two-part cyclic process ullage vapor is discharged through a vapor recovery system in which VOC are stripped from vented gas with a selectively gas permeable membrane. In the other part, the membrane is inoperative while gas pressure rises in the ullage. Ambient air is charged to the membrane separation unit during the latter part of the cycle.
Kinney, William H.; Dizgah, Azadeh Moradinezhad
2010-10-15
In this paper, we use a known duality between expanding and contracting cosmologies to construct a dual of the inflationary flow hierarchy applicable to contracting cosmologies such as ekpyrotic and cyclic models. We show that the inflationary flow equations are invariant under the duality and therefore apply equally well to inflation or to cyclic cosmology. We construct a self-consistent small-parameter approximation dual to the slow-roll approximation in inflation, and calculate the power spectrum of perturbations in this limit. We also recover the matter-dominated contracting solution of Wands, and the recently proposed adiabatic ekpyrosis solution.
Cyclic membrane separation process
Nemser, Stuart M.
2005-05-03
A cyclic process for controlling environmental emissions of volatile organic compounds (VOC) from vapor recovery in storage and dispensing operations of liquids maintains a vacuum in the storage tank ullage. In the first part of a two-part cyclic process ullage vapor is discharged through a vapor recovery system in which VOC are stripped from vented gas with a selectively gas permeable membrane. In the second part, the membrane is inoperative while gas pressure rises in the ullage. In one aspect of this invention, a vacuum is drawn in the membrane separation unit thus reducing overall VOC emissions.
Long distance quantum communication using quantum error correction
NASA Technical Reports Server (NTRS)
Gingrich, R. M.; Lee, H.; Dowling, J. P.
2004-01-01
We describe a quantum error correction scheme that can increase the effective absorption length of the communication channel. This device can play the role of a quantum transponder when placed in series, or a cyclic quantum memory when inserted in an optical loop.
Cyclic Voltammetry Experiment.
ERIC Educational Resources Information Center
Van Benschoten, James J.; And Others
1983-01-01
Describes a three-part experiment designed to introduce cyclic voltammetry to graduate/undergraduate students. Part 1 demonstrates formal reduction potential, redox electron transfer, diffusion coefficient, and electrochemical reversibility. Part 2 investigates electrochemical behavior of acetaminophen. Part 3 examines such experimental variables…
Intercalation of cyclic ketones into vanadyl phosphate
Zima, Vitezslav . E-mail: vitezslav.zima@upce.cz; Melanova, Klara; Benes, Ludvik; Trchova, Miroslava; Dybal, Jiri
2005-01-15
Intercalation compounds of vanadyl phosphate with cyclic ketones (cyclopentanone, cyclohexanone, 4-methylcyclohexanone, and 1,4-cyclohexanedione) were prepared from corresponding propanol or ethanol intercalates by a molecular exchange. The intercalates prepared were characterized using powder X-ray diffraction and thermogravimetric analysis. The intercalates are stable in dry environment and decompose slowly in humid air. Infrared and Raman spectra indicate that carbonyl oxygens of the guest molecules are coordinated to the vanadium atoms of the host layers. The local structure and interactions in the cyclopentanone intercalate have been suggested on the basis of quantum chemical calculations.
Cosmic perturbations through the cyclic ages
Erickson, Joel K.; Gratton, Steven; Steinhardt, Paul J.; Turok, Neil
2007-06-15
We analyze the evolution of cosmological perturbations in the cyclic model, paying particular attention to their behavior and interplay over multiple cycles. Our key results are: (1) galaxies and large scale structure present in one cycle are generated by the quantum fluctuations in the preceding cycle without interference from perturbations or structure generated in earlier cycles and without interfering with structure generated in later cycles; (2) the ekpyrotic phase, an epoch of gentle contraction with equation of state w>>1 preceding the hot big bang, makes the universe homogeneous, isotropic and flat within any given observer's horizon; and (3) although the universe is uniform within each observer's horizon, the structure of the cyclic universe on very large scales is more complex, owing to the effects of superhorizon length perturbations, and cannot be described globally as a Friedmann-Robertson-Walker cosmology. In particular, we show that the ekpyrotic contraction phase is so effective in smoothing, flattening and isotropizing the universe within the horizon that this phase alone suffices to solve the horizon and flatness problems even without an extended period of dark energy domination (a kind of low energy inflation). Instead, the cyclic model rests on a genuinely novel, noninflationary mechanism (ekpyrotic contraction) for resolving the classic cosmological conundrums.
NASA Astrophysics Data System (ADS)
Duhe, William; Biswas, Tirthibir
2014-03-01
We provide a comprehensive numerical study of the Emergent Cyclic Inflation scenario. This is a scenario where instead of traditional monotonic slow roll inflation, the universe expands over numerous short asymmetric cycles due to the production of entropy via interactions among different species. This is one of the very few scenarios of inflation which provides a nonsingular geodesically complete space-time and does not require any ``reheating'' mechanism. A special thanks to Loyola University for an excellent community to help this project grow.
Geometric phases and cyclic isotropic cosmologies
NASA Astrophysics Data System (ADS)
Banchi, Leonardo; Caravelli, Francesco
2016-05-01
In the present paper we study the evolution of the modes of a scalar field in a cyclic cosmology. In order to keep the discussion clear, we study the features of a scalar field in a toy model, a Friedman-Robertson-Walker Universe with a periodic scale factor, in which the Universe expands, contracts and bounces infinite times, in the approximation in which the dynamic features of this Universe are driven by some external factor, without the backreaction of the scalar field under study. In particular, we show that particle production exhibits features of the cyclic cosmology. Also, by studying the Berry phase of the scalar field, we show that contrary to what is commonly believed, the scalar field carries information from one bounce to another in the form of a global phase which occurs as generically non-zero. The Berry phase is then evaluated numerically in the case of the effective loop quantum cosmology closed Universe. We observe that Berry’s phase is non-zero, but that in the quantum regime the particle content is non-negligible.
Ada and cyclic runtime scheduling
NASA Technical Reports Server (NTRS)
Hood, Philip E.
1986-01-01
An important issue that must be faced while introducing Ada into the real time world is efficient and prodictable runtime behavior. One of the most effective methods employed during the traditional design of a real time system is the cyclic executive. The role cyclic scheduling might play in an Ada application in terms of currently available implementations and in terms of implementations that might be developed especially to support real time system development is examined. The cyclic executive solves many of the problems faced by real time designers, resulting in a system for which it is relatively easy to achieve approporiate timing behavior. Unfortunately a cyclic executive carries with it a very high maintenance penalty over the lifetime of the software that is schedules. Additionally, these cyclic systems tend to be quite fragil when any aspect of the system changes. The findings are presented of an ongoing SofTech investigation into Ada methods for real time system development. The topics covered include a description of the costs involved in using cyclic schedulers, the sources of these costs, and measures for future systems to avoid these costs without giving up the runtime performance of a cyclic system.
2009-01-01
Initially described in children, cyclic vomiting syndrome (CVS) is an idiopathic disorder that affects patients of all ages and is characterized by recurrent episodes of vomiting separated by symptom-free intervals or baseline health. Frequent misdiagnoses and delays in diagnosis often lead to years of recurrent vomiting. Similarities in the clinical features and symptoms of children and adults with CVS are often linked to migraines. Association with mitochondrial disorders and neuroendocrine dysfunction have been described in the pediatric CVS literature, whereas migraines, anxiety, and panic are common in adults with CVS. Various psychological, infectious, and physical stressors commonly precipitate episodes of CVS. Treatment is mostly empiric, with few controlled therapeutic studies conducted thus far. Associations with migraines have aided in developing pharmacologic treatment strategies for prophylaxis as well as abortive therapy during episodes, including the use of trip-tans. Most children outgrow CVS with time, though some children transition to migraine headaches or continue to have CVS as adults. Improved recognition of CVS in adults, along with the emergence of data in the use of anticonvulsants and antiemetics, may help further delineate pathophysiologic connections and therapeutic options for this debilitating disorder.
Botsford, J L; Harman, J G
1992-01-01
Cyclic AMP (cAMP) is found in a variety of prokaryotes including both eubacteria and archaebacteria. cAMP plays a role in regulating gene expression, not only for the classic inducible catabolic operons, but also for other categories. In the enteric coliforms, the effects of cAMP on gene expression are mediated through its interaction with and allosteric modification of a cAMP-binding protein (CRP). The CRP-cAMP complex subsequently binds specific DNA sequences and either activates or inhibits transcription depending upon the positioning of the complex relative to the promoter. Enteric coliforms have provided a model to explore the mechanisms involved in controlling adenylate cyclase activity, in regulating adenylate cyclase synthesis, and in performing detailed examinations of CRP-cAMP complex-regulated gene expression. This review summarizes recent work focused on elucidating the molecular mechanisms of CRP-cAMP complex-mediated processes. For other bacteria, less detail is known. cAMP has been implicated in regulating antibiotic production, phototrophic growth, and pathogenesis. A role for cAMP has been suggested in nitrogen fixation. Often the only data that support cAMP involvement in these processes includes cAMP measurement, detection of the enzymes involved in cAMP metabolism, or observed effects of high concentrations of the nucleotide on cell growth. PMID:1315922
Quantum image coding with a reference-frame-independent scheme
NASA Astrophysics Data System (ADS)
Chapeau-Blondeau, François; Belin, Etienne
2016-07-01
For binary images, or bit planes of non-binary images, we investigate the possibility of a quantum coding decodable by a receiver in the absence of reference frames shared with the emitter. Direct image coding with one qubit per pixel and non-aligned frames leads to decoding errors equivalent to a quantum bit-flip noise increasing with the misalignment. We show the feasibility of frame-invariant coding by using for each pixel a qubit pair prepared in one of two controlled entangled states. With just one common axis shared between the emitter and receiver, exact decoding for each pixel can be obtained by means of two two-outcome projective measurements operating separately on each qubit of the pair. With strictly no alignment information between the emitter and receiver, exact decoding can be obtained by means of a two-outcome projective measurement operating jointly on the qubit pair. In addition, the frame-invariant coding is shown much more resistant to quantum bit-flip noise compared to the direct non-invariant coding. For a cost per pixel of two (entangled) qubits instead of one, complete frame-invariant image coding and enhanced noise resistance are thus obtained.
Quantum image coding with a reference-frame-independent scheme
NASA Astrophysics Data System (ADS)
Chapeau-Blondeau, François; Belin, Etienne
2016-04-01
For binary images, or bit planes of non-binary images, we investigate the possibility of a quantum coding decodable by a receiver in the absence of reference frames shared with the emitter. Direct image coding with one qubit per pixel and non-aligned frames leads to decoding errors equivalent to a quantum bit-flip noise increasing with the misalignment. We show the feasibility of frame-invariant coding by using for each pixel a qubit pair prepared in one of two controlled entangled states. With just one common axis shared between the emitter and receiver, exact decoding for each pixel can be obtained by means of two two-outcome projective measurements operating separately on each qubit of the pair. With strictly no alignment information between the emitter and receiver, exact decoding can be obtained by means of a two-outcome projective measurement operating jointly on the qubit pair. In addition, the frame-invariant coding is shown much more resistant to quantum bit-flip noise compared to the direct non-invariant coding. For a cost per pixel of two (entangled) qubits instead of one, complete frame-invariant image coding and enhanced noise resistance are thus obtained.
On Improvements of Cyclic MUSIC
NASA Astrophysics Data System (ADS)
Yan, Huiqin; Fan, H. Howard
2005-12-01
Many man-made signals encountered in communications exhibit cyclostationarity. By exploiting cyclostationarity, cyclic MUSIC has been shown to be able to separate signals with different cycle frequencies, thus, to be able to perform signal selective direction of-arrival (DOA) estimation. However, as will be shown in this paper, the DOA estimation of cyclic MUSIC is actually biased. We show in this paper that by properly choosing the frequency for evaluating the steering vector, the bias of DOA estimation can be substantially reduced and the performance can be improved. Furthermore, we propose another algorithm exploiting cyclic conjugate correlation to further improve the performance of DOA estimation. Simulation results show the effectiveness of both of our methods.
Color visualization of cyclic magnitudes
NASA Astrophysics Data System (ADS)
Restrepo, Alfredo; Estupiñán, Viviana
2014-02-01
We exploit the perceptual, circular ordering of the hues in a technique for the visualization of cyclic variables. The hue is thus meaningfully used for the indication of variables such as the azimuth and the units of the measurement of time. The cyclic (or circular) variables may be both of the continuous type or the discrete type; among the first there is azimuth and among the last you find the musical notes and the days of the week. A correspondence between the values of a cyclic variable and the chromatic hues, where the natural circular ordering of the variable is respected, is called a color code for the variable. We base such a choice of hues on an assignment of of the unique hues red, yellow, green and blue, or one of the 8 even permutations of this ordered list, to 4 cardinal values of the cyclic variable, suitably ordered; color codes based on only 3 cardinal points are also possible. Color codes, being intuitive, are easy to remember. A possible low accuracy when reading instruments that use this technique is compensated by fast, ludic and intuitive readings; also, the use of a referential frame makes readings precise. An achromatic version of the technique, that can be used by dichromatic people, is proposed.
Cyclical magnetic field flow fractionation
NASA Astrophysics Data System (ADS)
Tasci, T. O.; Johnson, W. P.; Gale, B. K.
2012-04-01
In this study, a new magnetic field flow fractionation (FFF) system was designed and modeled by using finite element simulations. Other than current magnetic FFF systems, which use static magnetic fields, our system uses cyclical magnetic fields. Results of the simulations show that our cyclical magnetic FFF system can be used effectively for the separation of magnetic nanoparticles. Cyclical magnetic FFF system is composed of a microfluidic channel (length = 5 cm, height = 30 μm) and 2 coils. Square wave currents of 1 Hz (with 90 deg of phase difference) were applied to the coils. By using Comsol Multiphysics 3.5a, magnetic field profile and corresponding magnetic force exerted on the magnetite nanoparticles were calculated. The magnetic force data were exported from Comsol to Matlab. In Matlab, a parabolic flow profile with maximum flow speed of 0.4 mL/h was defined. Particle trajectories were obtained by the calculation of the particle speeds resulted from both magnetic and hydrodynamic forces. Particle trajectories of the particles with sizes ranging from 10 to 50 nm were simulated and elution times of the particles were calculated. Results show that there is a significant difference between the elution times of the particles so that baseline separation of the particles can be obtained. In this work, it is shown that by the application of cyclical magnetic fields, the separation of magnetic nanoparticles can be done efficiently.
Buffering in cyclic gene networks
NASA Astrophysics Data System (ADS)
Glyzin, S. D.; Kolesov, A. Yu.; Rozov, N. Kh.
2016-06-01
We consider cyclic chains of unidirectionally coupled delay differential-difference equations that are mathematical models of artificial oscillating gene networks. We establish that the buffering phenomenon is realized in these system for an appropriate choice of the parameters: any given finite number of stable periodic motions of a special type, the so-called traveling waves, coexist.
Oehme, Daniel P; Brownlee, Robert T C; Wilson, David J D
2013-03-01
X-ray crystallography studies have identified that most cyclic inhibitors of HIV protease (including cyclic ureas) bind in a symmetric manner, however some cyclic inhibitors, such as cyclic sulfamides, bind in a non-symmetric manner. This raises the question as to whether it is possible for cyclic sulfamides to bind symmetrically and conversely for cyclic ureas to bind non-symmetrically. Herein we report an analysis of the conformational preference of cyclic ureas and sulfamides both free in solution and bound to HIV protease, including an investigation of the effect of branching. Quantum chemical calculations (B3LYP, M06-2X, MP2, CCSD(T)) predict the cyclic urea to prefer a symmetric conformation in solution, with a large activation barrier towards inter-conversion to the non-symmetric conformation. This differs from the cyclic sulfamides, which marginally prefer a non-symmetric conformation with a much smaller barrier to inter-conversion making it more likely for a non-preferred conformation to be observed. It is predicted that the cyclic scaffold itself favours a symmetric form, while branching induces a preference for a non-symmetric form. MD simulations on the free inhibitors identified inter-conversion with the cyclic sulfamides but not the cyclic ureas, in support of the quantum chemical results. MM-PB(GB)SA calculations on the cyclic inhibitors bound to HIV protease corroborate the X-ray crystallography studies, identifying the cyclic ureas to bind symmetrically and the cyclic sulfamides in a non-symmetrical manner. While the non-preferred form of the sulfamide may well be present as a free molecule in solution, our results suggest that it is unlikely to bind to HIV protease in a symmetric manner. PMID:23149763
Modulators of cyclic AMP systems.
Hess, S M; Chasin, M; Free, C A; Harris, D N
1975-01-01
On the basis of the data reported here, one may conclude that although many agents that act in the central nervous system are modulators of the action of cyclic AMP, it is difficult to establish a direct connection between the pharmacologic activity and the levels of cyclic AMP in the brain. This lack of interrelation applies to the benzodiazepines as well as to the pyrazolopyridines. The data for members of the latter group are somewhat frustrating in this regard, since an excellent correlation has been shown to exist between the potency of inhibition of PDE and activity in the antianxiety test. In measurements of steroidogenesis in the isolated adrenal cell, the correlation between activity in vito and the conflict assay is even better. The data presented here and reported elsewhere (Shimizu et al., 1974; Kelly et al., 1974; Mayer and King, 1974; King and Mayer, 1974) provide evidence that agents that act as inhibitors of PDE in cell-free systems exert their influence on cyclic AMP in tissue slices of the brain of guinea pigs by mechanisms that seem not to be related to an effect on PDE. Papaverine, and possibly chlordiazepoxide, may act by releasing agonists that, in turn, stimulate the accumulation of cyclic AMP. This activity is blocked bo other inhibitors of PDE, such as theophyline. Results obtained by the use of platelets are refreshingly clear. Inhibition of aggregation has been shown to occur when the level of cyclic AMP is raised, and a suggestive exists that the most potent inhibitors of platelet PDE are the best potentiators of the action of PGE1 in blocking aggregation. The study utilizing drugs collected from a large number of therapeutic classes makes clear that it is difficult to attribute the mechanism of action for any of the classes studied to modulation of cyclic AMP. An unexpected finding of this study, however, was the fact that pharmacologic agents include an unusually large number of inhibitors of PDE as compared with agents chosen at
Quantum Computation and Quantum Information
NASA Astrophysics Data System (ADS)
Nielsen, Michael A.; Chuang, Isaac L.
2010-12-01
Part I. Fundamental Concepts: 1. Introduction and overview; 2. Introduction to quantum mechanics; 3. Introduction to computer science; Part II. Quantum Computation: 4. Quantum circuits; 5. The quantum Fourier transform and its application; 6. Quantum search algorithms; 7. Quantum computers: physical realization; Part III. Quantum Information: 8. Quantum noise and quantum operations; 9. Distance measures for quantum information; 10. Quantum error-correction; 11. Entropy and information; 12. Quantum information theory; Appendices; References; Index.
Supramolecular nesting of cyclic polymers
NASA Astrophysics Data System (ADS)
Kondratuk, Dmitry V.; Perdigão, Luís M. A.; Esmail, Ayad M. S.; O'Shea, James N.; Beton, Peter H.; Anderson, Harry L.
2015-04-01
Advances in template-directed synthesis make it possible to create artificial molecules with protein-like dimensions, directly from simple components. These synthetic macromolecules have a proclivity for self-organization that is reminiscent of biopolymers. Here, we report the synthesis of monodisperse cyclic porphyrin polymers, with diameters of up to 21 nm (750 C-C bonds). The ratio of the intrinsic viscosities for cyclic and linear topologies is 0.72, indicating that these polymers behave as almost ideal flexible chains in solution. When deposited on gold surfaces, the cyclic polymers display a new mode of two-dimensional supramolecular organization, combining encapsulation and nesting; one nanoring adopts a near-circular conformation, thus allowing a second nanoring to be captured within its perimeter, in a tightly folded conformation. Scanning tunnelling microscopy reveals that nesting occurs in combination with stacking when nanorings are deposited under vacuum, whereas when they are deposited directly from solution under ambient conditions there is stacking or nesting, but not a combination of both.
Wyatt, Todd A.
2015-01-01
Motile cilia of the lungs respond to environmental challenges by increasing their ciliary beat frequency in order to enhance mucociliary clearance as a fundamental tenant of innate defense. One important second messenger in transducing the regulable nature of motile cilia is cyclic guanosine 3′,5′-monophosphate (cGMP). In this review, the history of cGMP action is presented and a survey of the existing data addressing cGMP action in ciliary motility is presented. Nitric oxide (NO)-mediated regulation of cGMP in ciliated cells is presented in the context of alcohol-induced cilia function and dysfunction. PMID:26264028
Langbein, W.B.
1955-01-01
A common problem in hydrology is to fit a smooth curve to cyclic or periodic data, either to define the most probable values of the data or to test some principle that one wishes to demonstrate. This study treats of those problems where the length or period of the cycle is know beforehand - as a day, year, or meander length for example. Curve-fitting can be made by free-hand drawing, and where the data are closely aligned this method offers the simplest and most direct course. However, there are many problems where the best fit is far from obvious, and analytical methods may be necessary.
Insights into How Cyclic Peptides Switch Conformations.
McHugh, Sean M; Rogers, Julia R; Yu, Hongtao; Lin, Yu-Shan
2016-05-10
Cyclic peptides have recently emerged as promising modulators of protein-protein interactions. However, it is currently highly difficult to predict the structures of cyclic peptides owing to their rugged conformational free energy landscape, which prevents sampling of all thermodynamically relevant conformations. In this article, we first investigate how a relatively flexible cyclic hexapeptide switches conformations. It is found that, although the circular geometry of small cyclic peptides of size 6-8 may require rare, coherent dihedral changes to sample a new conformation, the changes are rather local, involving simultaneous changes of ϕi and ψi or ψi and ϕi+1. The understanding of how these cyclic peptides switch conformations enables the use of metadynamics simulations with reaction coordinates specifically targeting such coupled two-dihedral changes to effectively sample cyclic peptide conformational space. PMID:27031286
Advances in targeting cyclic nucleotide phosphodiesterases
Maurice, Donald H.; Ke, Hengming; Ahmad, Faiyaz; Wang, Yousheng; Chung, Jay; Manganiello, Vincent C.
2014-01-01
Cyclic nucleotide phosphodiesterases (PDEs) catalyse the hydrolysis of cyclic AMP and cyclic GMP, thereby regulating the intracellular concentrations of these cyclic nucleotides, their signalling pathways and, consequently, myriad biological responses in health and disease. Currently, a small number of PDE inhibitors are used clinically for treating the pathophysiological dysregulation of cyclic nucleotide signalling in several disorders, including erectile dysfunction, pulmonary hypertension, acute refractory cardiac failure, intermittent claudication and chronic obstructive pulmonary disease. However, pharmaceutical interest in PDEs has been reignited by the increasing understanding of the roles of individual PDEs in regulating the subcellular compartmentalization of specific cyclic nucleotide signalling pathways, by the structure-based design of novel specific inhibitors and by the development of more sophisticated strategies to target individual PDE variants. PMID:24687066
Advances in targeting cyclic nucleotide phosphodiesterases.
Maurice, Donald H; Ke, Hengming; Ahmad, Faiyaz; Wang, Yousheng; Chung, Jay; Manganiello, Vincent C
2014-04-01
Cyclic nucleotide phosphodiesterases (PDEs) catalyse the hydrolysis of cyclic AMP and cyclic GMP, thereby regulating the intracellular concentrations of these cyclic nucleotides, their signalling pathways and, consequently, myriad biological responses in health and disease. Currently, a small number of PDE inhibitors are used clinically for treating the pathophysiological dysregulation of cyclic nucleotide signalling in several disorders, including erectile dysfunction, pulmonary hypertension, acute refractory cardiac failure, intermittent claudication and chronic obstructive pulmonary disease. However, pharmaceutical interest in PDEs has been reignited by the increasing understanding of the roles of individual PDEs in regulating the subcellular compartmentalization of specific cyclic nucleotide signalling pathways, by the structure-based design of novel specific inhibitors and by the development of more sophisticated strategies to target individual PDE variants. PMID:24687066
Cyclic Imide Dioxime: Formation and Hydrolytic Stability
Kang, S.O.; Vukovic, Sinisa; Custelcean, Radu; Hay, Benjamin
2012-01-01
Poly(acrylamidoximes) play an important role in the uranium extraction from seawater. The present work reports solution studies of simple analogs to address the formation and stability of two binding sites present in these polymers, open-chain amidoximes and cyclic imide dioximes, including: 1) conditions that maximize the formation of the cyclic form, 2) existence of a base-induced conversion from open-chain to cyclic form, and 3) degradation under acid and base conditions.
Cell reorientation under cyclic stretching.
Livne, Ariel; Bouchbinder, Eran; Geiger, Benjamin
2014-01-01
Mechanical cues from the extracellular microenvironment play a central role in regulating the structure, function and fate of living cells. Nevertheless, the precise nature of the mechanisms and processes underlying this crucial cellular mechanosensitivity remains a fundamental open problem. Here we provide a novel framework for addressing cellular sensitivity and response to external forces by experimentally and theoretically studying one of its most striking manifestations--cell reorientation to a uniform angle in response to cyclic stretching of the underlying substrate. We first show that existing approaches are incompatible with our extensive measurements of cell reorientation. We then propose a fundamentally new theory that shows that dissipative relaxation of the cell's passively-stored, two-dimensional, elastic energy to its minimum actively drives the reorientation process. Our theory is in excellent quantitative agreement with the complete temporal reorientation dynamics of individual cells measured over a wide range of experimental conditions, thus elucidating a basic aspect of mechanosensitivity. PMID:24875391
Cyclic strength of hard metals
Sereda, N.N.; Gerikhanov, A.K.; Koval'chenko, M.S.; Pedanov, L.G.; Tsyban', V.A.
1986-02-01
The authors study the strength of hard-metal specimens and structural elements under conditions of cyclic loading since many elements of processing plants, equipment, and machines are made of hard metals. Fatigue tests were conducted on KTS-1N, KTSL-1, and KTNKh-70 materials, which are titanium carbide hard metals cemented with nickel-molybdenum, nickelcobalt-chromium, and nickel-chromium alloys, respectively. As a basis of comparison, the standard VK-15 (WC+15% Co) alloy was used. Some key physicomechanical characteristics of the materials investigated are presented. On time bases not exceeding 10/sup 6/ cycles, titanium carbide hard metals are comparable in fatigue resistance to the standard tungstencontaining hard metals.
Cell reorientation under cyclic stretching
NASA Astrophysics Data System (ADS)
Livne, Ariel; Bouchbinder, Eran; Geiger, Benjamin
2014-05-01
Mechanical cues from the extracellular microenvironment play a central role in regulating the structure, function and fate of living cells. Nevertheless, the precise nature of the mechanisms and processes underlying this crucial cellular mechanosensitivity remains a fundamental open problem. Here we provide a novel framework for addressing cellular sensitivity and response to external forces by experimentally and theoretically studying one of its most striking manifestations—cell reorientation to a uniform angle in response to cyclic stretching of the underlying substrate. We first show that existing approaches are incompatible with our extensive measurements of cell reorientation. We then propose a fundamentally new theory that shows that dissipative relaxation of the cell’s passively-stored, two-dimensional, elastic energy to its minimum actively drives the reorientation process. Our theory is in excellent quantitative agreement with the complete temporal reorientation dynamics of individual cells measured over a wide range of experimental conditions, thus elucidating a basic aspect of mechanosensitivity.
Cyclic Linearization and Island Repair in Sluicing
ERIC Educational Resources Information Center
Qiu, Chunan
2009-01-01
Cyclic Linearization is adopted to account for the island repair of Sluicing in English. The extraction of wh-phrase out of certain islands undergoes non-successive-cyclic movement, which yields conflicting ordering statements. The derivation can be rescued by deleting all ordering statements in IP, including those conflicting ones. Two arguments…
Twisted Cyclic Cohomology and Modular Fredholm Modules
NASA Astrophysics Data System (ADS)
Rennie, Adam; Sitarz, Andrzej; Yamashita, Makoto
2013-07-01
Connes and Cuntz showed in [Comm. Math. Phys. 114 (1988), 515-526] that suitable cyclic cocycles can be represented as Chern characters of finitely summable semifinite Fredholm modules. We show an analogous result in twisted cyclic cohomology using Chern characters of modular Fredholm modules. We present examples of modular Fredholm modules arising from Podleś spheres and from SUq(2).
Phase behaviors of cyclic diblock copolymers.
Zhang, Guojie; Fan, Zhongyong; Yang, Yuliang; Qiu, Feng
2011-11-01
A spectral method of self-consistent field theory has been applied to AB cyclic block copolymers. Phase behaviors of cyclic diblock copolymers, such as order-disorder transition, order-order transition, and domain spacing size, have been studied, showing good consistency with previous experimental and theoretical results. Compared to linear diblocks, cyclic diblocks are harder to phase separate due to the topological constraint of the ring structure. A direct disorder-to-cylinder transition window is observed in the phase diagram, which is significantly different from the mean field phase diagram of linear diblock copolymers. The domain spacing size ratio between cyclic and linear diblock copolymers is typically close to 0.707, indicating in segregation that the cyclic polymer can be considered to be made up of linear diblocks with half of the original chain length. PMID:22070321
Russell, L; Yamazaki, H
1978-05-01
The amount of asparaginase II in an Escherichia coli wild-type strain (cya+, crp+) markedly increased upon a shift from aerobic to anaerobic growth. However, no such increase occurred in a mutant (cya) lacking cyclic AMP synthesis unless supplemented with exogenous cyclic AMP. Since a mutant (crp) deficient in cyclic AMP receptor protein also did not support the anaerobic formation of this enzyme, it is concluded that the formation of E. coli asparaginase II depends on both cyclic AMP and cyclic AMP receptor protein. PMID:207402
An order-by-disorder process in the cyclic phase of spin-2 condensate with a weak magnetic field
Zheng, Gong-Ping; Xu, Lei-Kuan; Qin, Shuai-Feng; Jian, Wen-Tian; Liang, J.-Q.
2013-07-15
We present in this paper a model study on the “order-by-disorder” process in the cyclic phase of spin-2 condensate, which forms a family of incommensurable, spiral degenerate ground states. On the basis of the ordering mechanism of entropic splitting, it is demonstrated that the energy corrections resulting from quantum fluctuations of disorder lift the accidental degeneracy of the cyclic configurations and thus lead to an eventual spiral order called the cyclic order. The order-by-disorder phenomenon is then realized even if the magnetic field exists. Finally, we show that our theoretic observations can be verified experimentally by direct detection of the cyclic order in the {sup 87}Rb condensate of a spin-2 manifold with a weak magnetic field. -- Highlights: •A model for the order-by-disorder process in the cyclic phase of spin-2 condensate is presented. •The second-order quantum fluctuations of the mean-field states are studied. •The energy corrections lift the accidental degeneracy of the cyclic configurations. •The order-by-disorder phenomenon is realized even if a magnetic field exists. •The theoretic observations can be verified experimentally for {sup 87}Rb condensate.
Hidden observables in neutron quantum interferometry
NASA Astrophysics Data System (ADS)
Rauch, Helmut; Baron, Matthias; Filipp, Stefan; Hasegawa, Yuji; Lemmel, Hartmut; Loidl, Rudolf
2006-11-01
Neutron interferometry using monolithic perfect single crystals has become an important tool for fundamental, nuclear, and solid-state physics research. New features of quantum mechanics become measurable by means of neutron interferometry. Such features are quantum phases, which provide a more direct access to properties of wave functions and permit wave function reconstruction, and wave function engineering. Most recently, new experiments concerning off-diagonal and non-cyclic geometrical phases, confinement induced phases, and contextuality related experiments have been performed. These experiments show an intrinsic entanglement of different degrees of freedom of a single particle. Proper post-selection experiments yield to more quantum complete experiments and may help to make quantum mechanics less mystic. Unavoidable quantum losses may play an important role to explain the transition from the quantum to the classical world. All these investigations concern the heart of quantum mechanics and demonstrate the non-local feature of this theory.
Mixed Strategies in cyclic competition
NASA Astrophysics Data System (ADS)
Intoy, Ben; Pleimling, Michel
2015-03-01
Physicists have been using evolutionary game theory to model and simulate cyclically competing species, with applications to lizard mating strategies and competing bacterial strains. However these models assume that each agent plays the same strategy, which is called a pure strategy in game theory, until they are beaten by a better strategy which they immediately adopt. We relax this constraint of an agent playing a single strategy by instead letting the agent pick its strategy randomly from a probability distribution, which is called a mixed strategy in game theory. This scheme is very similar to multiple occupancy models seen in the literature, the major difference being that interactions happen between sites rather than within them. Choosing strategies out of a distribution also has applications to economic/social systems such as the public goods game. We simulate a model of mixed strategy and cylic competition on a one-dimensional lattice with three and four strategies and find interesting spatial and stability properties depending on how discretized the choice of strategy is for the agents. This work is supported by the US National Science Foundation through Grant DMR-1205309.
Processable Cyclic Peptide Nanotubes with Tunable Interiors
Hourani, Rami; Zhang, Chen; van der Weegen, Rob; Ruiz, Luis; Li, Changyi; Keten, Sinan; Helms, Brett A.; Xu, Ting
2011-09-06
A facile route to generate cyclic peptide nanotubes with tunable interiors is presented. By incorporating 3-amino-2-methylbenzoic acid in the d,l-alternating primary sequence of a cyclic peptide, a functional group can be presented in the interior of the nanotubes without compromising the formation of high aspect ratio nanotubes. The new design of such a cyclic peptide also enables one to modulate the nanotube growth process to be compatible with the polymer processing window without compromising the formation of high aspect ratio nanotubes, thus opening a viable approach toward molecularly defined porous membranes.
Asymmetric cyclic evolution in polymerised cosmology
Hrycyna, Orest; Mielczarek, Jakub; Szydłowski, Marek E-mail: jakub.mielczarek@uj.edu.pl
2009-12-01
The dynamical systems methods are used to study evolution of the polymerised scalar field cosmologies with the cosmological constant. We have found all evolutional paths admissible for all initial conditions on the two-dimensional phase space. We have shown that the cyclic solutions are generic. The exact solution for polymerised cosmology is also obtained. Two basic cases are investigated, the polymerised scalar field and the polymerised gravitational and scalar field part. In the former the division on the cyclic and non-cyclic behaviour is established following the sign of the cosmological constant. The value of the cosmological constant is upper bounded purely from the dynamical setting.
An order-by-disorder process in the cyclic phase of spin-2 condensate with a weak magnetic field
NASA Astrophysics Data System (ADS)
Zheng, Gong-Ping; Xu, Lei-Kuan; Qin, Shuai-Feng; Jian, Wen-Tian; Liang, J.-Q.
2013-07-01
We present in this paper a model study on the "order-by-disorder" process in the cyclic phase of spin-2 condensate, which forms a family of incommensurable, spiral degenerate ground states. On the basis of the ordering mechanism of entropic splitting, it is demonstrated that the energy corrections resulting from quantum fluctuations of disorder lift the accidental degeneracy of the cyclic configurations and thus lead to an eventual spiral order called the cyclic order. The order-by-disorder phenomenon is then realized even if the magnetic field exists. Finally, we show that our theoretic observations can be verified experimentally by direct detection of the cyclic order in the 87Rb condensate of a spin-2 manifold with a weak magnetic field.
Geodesically complete analytic solutions for a cyclic universe
Bars, Itzhak; Chen, Shih-Hung; Turok, Neil
2011-10-15
We present analytic solutions to a class of cosmological models described by a canonical scalar field minimally coupled to gravity and experiencing self interactions through a hyperbolic potential. Using models and methods inspired by 2T-physics, we show how analytic solutions can be obtained in flat/open/closed Friedmann-Robertson-Walker universes. Among the analytic solutions, there are many interesting geodesically complete cyclic solutions in which the universe bounces at either zero or finite sizes. When geodesic completeness is imposed, it restricts models and their parameters to a certain parameter subspace, including some quantization conditions on initial conditions in the case of zero-size bounces, but no conditions on initial conditions for the case of finite-size bounces. We will explain the theoretical origin of our model from the point of view of 2T-gravity as well as from the point of view of the colliding branes scenario in the context of M-theory. We will indicate how to associate solutions of the quantum Wheeler-deWitt equation with our classical analytic solutions, mention some physical aspects of the cyclic solutions, and outline future directions.
Synchronization in chaotic oscillators by cyclic coupling
NASA Astrophysics Data System (ADS)
Olusola, O. I.; Njah, A. N.; Dana, S. K.
2013-07-01
We introduce a type of cyclic coupling to investigate synchronization of chaotic oscillators. We derive analytical solutions of the critical coupling for stable synchronization under the cyclic coupling for the Rössler system and the Lorenz oscillator as paradigmatic illustration. Based on the master stability function (MSF) approach, the analytical results on critical coupling are verified numerically. An enhancing effect in terms of lowering the critical coupling or enlarging the synchronization window in a critical coupling space is noticed. The cyclic coupling is also applied in other models, Hindmarsh-Rose model, Sprott system, Chen system and forced Duffing system to confirm the enhancing effect. The cyclic coupling allows tuning of two coupling constants in reverse directions when an optimal control of synchronization is feasible.
Antimicrobial Cyclic Peptides for Plant Disease Control
Lee, Dong Wan; Kim, Beom Seok
2015-01-01
Antimicrobial cyclic peptides derived from microbes bind stably with target sites, have a tolerance to hydrolysis by proteases, and a favorable degradability under field conditions, which make them an attractive proposition for use as agricultural fungicides. Antimicrobial cyclic peptides are classified according to the types of bonds within the ring structure; homodetic, heterodetic, and complex cyclic peptides, which in turn reflect diverse physicochemical features. Most antimicrobial cyclic peptides affect the integrity of the cell envelope. This is achieved through direct interaction with the cell membrane or disturbance of the cell wall and membrane component biosynthesis such as chitin, glucan, and sphingolipid. These are specific and selective targets providing reliable activity and safety for non-target organisms. Synthetic cyclic peptides produced through combinatorial chemistry offer an alternative approach to develop antimicrobials for agricultural uses. Those synthesized so far have been studied for antibacterial activity, however, the recent advancements in powerful technologies now promise to provide novel antimicrobial cyclic peptides that are yet to be discovered from natural resources. PMID:25774105
Quantum correlation via quantum coherence
NASA Astrophysics Data System (ADS)
Yu, Chang-shui; Zhang, Yang; Zhao, Haiqing
2014-06-01
Quantum correlation includes quantum entanglement and quantum discord. Both entanglement and discord have a common necessary condition—quantum coherence or quantum superposition. In this paper, we attempt to give an alternative understanding of how quantum correlation is related to quantum coherence. We divide the coherence of a quantum state into several classes and find the complete coincidence between geometric (symmetric and asymmetric) quantum discords and some particular classes of quantum coherence. We propose a revised measure for total coherence and find that this measure can lead to a symmetric version of geometric quantum correlation, which is analytic for two qubits. In particular, this measure can also arrive at a monogamy equality on the distribution of quantum coherence. Finally, we also quantify a remaining type of quantum coherence and find that for two qubits, it is directly connected with quantum nonlocality.
NASA Astrophysics Data System (ADS)
Le Gouët, Jean-Louis; Moiseev, Sergey
2012-06-01
Interaction of quantum radiation with multi-particle ensembles has sparked off intense research efforts during the past decade. Emblematic of this field is the quantum memory scheme, where a quantum state of light is mapped onto an ensemble of atoms and then recovered in its original shape. While opening new access to the basics of light-atom interaction, quantum memory also appears as a key element for information processing applications, such as linear optics quantum computation and long-distance quantum communication via quantum repeaters. Not surprisingly, it is far from trivial to practically recover a stored quantum state of light and, although impressive progress has already been accomplished, researchers are still struggling to reach this ambitious objective. This special issue provides an account of the state-of-the-art in a fast-moving research area that makes physicists, engineers and chemists work together at the forefront of their discipline, involving quantum fields and atoms in different media, magnetic resonance techniques and material science. Various strategies have been considered to store and retrieve quantum light. The explored designs belong to three main—while still overlapping—classes. In architectures derived from photon echo, information is mapped over the spectral components of inhomogeneously broadened absorption bands, such as those encountered in rare earth ion doped crystals and atomic gases in external gradient magnetic field. Protocols based on electromagnetic induced transparency also rely on resonant excitation and are ideally suited to the homogeneous absorption lines offered by laser cooled atomic clouds or ion Coulomb crystals. Finally off-resonance approaches are illustrated by Faraday and Raman processes. Coupling with an optical cavity may enhance the storage process, even for negligibly small atom number. Multiple scattering is also proposed as a way to enlarge the quantum interaction distance of light with matter. The
Cyclic fatigue mechanisms in partially stabilized zirconia
Hoffman, M.J.; Wakayama, Shuichi; Kawahara, Masanori; Mai, Y.W.; Kishi, Teruo
1995-12-31
Cyclic fatigue crack growth rate and crack resistance curve testing were undertaken on 6 different grades of Mg-PSZ. The width of the transformation zone at the flanks of the cracks was determined using Raman spectroscopy and, combined with R-curve toughening values, used to ascertain the level of crack-tip shielding during cyclic fatigue crack growth and hence the crack-tip stress intensity factor amplitude. By normalizing the crack-tip stress intensity factor amplitude with the intrinsic toughness of the material, it was found that the cyclic fatigue threshold stress intensity factor was independent of the extent of crack-tip shielding and a function of the stress intensity factor at the crack tip. In situ SEM observations of cyclic fatigue revealed crack bridging by uncracked ligaments and the precipitate phase. Under cyclic loading the precipitate bridges were postulated to undergo frictional degradation at the precipitate/matrix interface with the degree of degradation determined by the cyclic amplitude. Acoustic emission testing revealed acoustic emissions at three distinct levels during the loading cycle: firstly, near the maximum applied stress intensity factor caused by crack propagation; secondly, at the mid-range of the applied stress intensity factor attributed to crack closure near the crack tip, presumably as a result of transformation induced dilation; and thirdly, intermittently near the base of the loading cycle as a result of fracture surface contact due to surface roughness at a significant distance behind the crack tip. Crack closure near the crack tip due to dilation is proposed to significantly reduce the crack tip stress intensity factor amplitude and hence the degree of cyclic fatigue.
Measuring Cyclic Error in Laser Heterodyne Interferometers
NASA Technical Reports Server (NTRS)
Ryan, Daniel; Abramovici, Alexander; Zhao, Feng; Dekens, Frank; An, Xin; Azizi, Alireza; Chapsky, Jacob; Halverson, Peter
2010-01-01
An improved method and apparatus have been devised for measuring cyclic errors in the readouts of laser heterodyne interferometers that are configured and operated as displacement gauges. The cyclic errors arise as a consequence of mixing of spurious optical and electrical signals in beam launchers that are subsystems of such interferometers. The conventional approach to measurement of cyclic error involves phase measurements and yields values precise to within about 10 pm over air optical paths at laser wavelengths in the visible and near infrared. The present approach, which involves amplitude measurements instead of phase measurements, yields values precise to about .0.1 microns . about 100 times the precision of the conventional approach. In a displacement gauge of the type of interest here, the laser heterodyne interferometer is used to measure any change in distance along an optical axis between two corner-cube retroreflectors. One of the corner-cube retroreflectors is mounted on a piezoelectric transducer (see figure), which is used to introduce a low-frequency periodic displacement that can be measured by the gauges. The transducer is excited at a frequency of 9 Hz by a triangular waveform to generate a 9-Hz triangular-wave displacement having an amplitude of 25 microns. The displacement gives rise to both amplitude and phase modulation of the heterodyne signals in the gauges. The modulation includes cyclic error components, and the magnitude of the cyclic-error component of the phase modulation is what one needs to measure in order to determine the magnitude of the cyclic displacement error. The precision attainable in the conventional (phase measurement) approach to measuring cyclic error is limited because the phase measurements are af-
Geometrical Phases in Quantum Mechanics
NASA Astrophysics Data System (ADS)
Christian, Joy Julius
In quantum mechanics, the path-dependent geometrical phase associated with a physical system, over and above the familiar dynamical phase, was initially discovered in the context of adiabatically changing environments. Subsequently, Aharonov and Anandan liberated this phase from the original formulation of Berry, which used Hamiltonians, dependent on curves in a classical parameter space, to represent the cyclic variations of the environments. Their purely quantum mechanical treatment, independent of Hamiltonians, instead used the non-trivial topological structure of the projective space of one-dimensional subspaces of an appropriate Hilbert space. The geometrical phase, in their treatment, results from a parallel transport of the time-dependent pure quantum states along a curve in this space, which is endowed with an abelian connection. Unlike Berry, they were able to achieve this without resort to an adiabatic approximation or to a time-independent eigenvalue equation. Prima facie, these two approaches are conceptually quite different. After a review of both approaches, an exposition bridging this apparent conceptual gap is given; by rigorously analyzing a model composite system, it is shown that, in an appropriate correspondence limit, the Berry phase can be recovered as a special case from the Aharonov-Anandan phase. Moreover, the model composite system is used to show that Berry's correction to the traditional Born-Oppenheimer energy spectra indeed brings the spectra closer to the exact results. Then, an experimental arrangement to measure geometrical phases associated with cyclic and non-cyclic variations of quantum states of an entangled composite system is proposed, utilizing the fundamental ideas of the recently opened field of two-particle interferometry. This arrangement not only resolves the controversy regarding the true nature of the phases associated with photon states, but also unequivocally predicts experimentally accessible geometrical phases in a
Novel pH-Sensitive Cyclic Peptides
Weerakkody, Dhammika; Moshnikova, Anna; El-Sayed, Naglaa Salem; Adochite, Ramona-Cosmina; Slaybaugh, Gregory; Golijanin, Jovana; Tiwari, Rakesh K.; Andreev, Oleg A.; Parang, Keykavous; Reshetnyak, Yana K.
2016-01-01
A series of cyclic peptides containing a number of tryptophan (W) and glutamic acid (E) residues were synthesized and evaluated as pH-sensitive agents for targeting of acidic tissue and pH-dependent cytoplasmic delivery of molecules. Biophysical studies revealed the molecular mechanism of peptides action and localization within the lipid bilayer of the membrane at high and low pHs. The symmetric, c[(WE)4WC], and asymmetric, c[E4W5C], cyclic peptides translocated amanitin, a polar cargo molecule of similar size, across the lipid bilayer and induced cell death in a pH- and concentration-dependent manner. Fluorescently-labelled peptides were evaluated for targeting of acidic 4T1 mammary tumors in mice. The highest tumor to muscle ratio (5.6) was established for asymmetric cyclic peptide, c[E4W5C], at 24 hours after intravenous administration. pH-insensitive cyclic peptide c[R4W5C], where glutamic acid residues (E) were replaced by positively charged arginine residues (R), did not exhibit tumor targeting. We have introduced a novel class of cyclic peptides, which can be utilized as a new pH-sensitive tool in investigation or targeting of acidic tissue. PMID:27515582
Cyclic depsipeptides as potential cancer therapeutics.
Kitagaki, Jirouta; Shi, Genbin; Miyauchi, Shizuka; Murakami, Shinya; Yang, Yili
2015-03-01
Cyclic depsipeptides are polypeptides in which one or more amino acid is replaced by a hydroxy acid, resulting in the formation of at least one ester bond in the core ring structure. Many natural cyclic depsipeptides possessing intriguing structural and biological properties, including antitumor, antifungal, antiviral, antibacterial, anthelmintic, and anti-inflammatory activities, have been identified from fungi, plants, and marine organisms. In particular, the potent effects of cyclic depsipeptides on tumor cells have led to a number of clinical trials evaluating their potential as chemotherapeutic agents. Although many of the trials have not achieved the desired results, romidepsin (FK228), a bicyclic depsipeptide that inhibits histone deacetylase, has been shown to have clinical efficacy in patients with refractory cutaneous T-cell lymphoma and has received Food and Drug Administration approval for use in treatment. In this review, we discuss antitumor cyclic depsipeptides that have undergone clinical trials and focus on their structural features, mechanisms, potential applications in chemotherapy, and pharmacokinetic and toxicity data. The results of this study indicate that cyclic depsipeptides could be a rich source of new cancer therapeutics. PMID:25419631
Novel pH-Sensitive Cyclic Peptides.
Weerakkody, Dhammika; Moshnikova, Anna; El-Sayed, Naglaa Salem; Adochite, Ramona-Cosmina; Slaybaugh, Gregory; Golijanin, Jovana; Tiwari, Rakesh K; Andreev, Oleg A; Parang, Keykavous; Reshetnyak, Yana K
2016-01-01
A series of cyclic peptides containing a number of tryptophan (W) and glutamic acid (E) residues were synthesized and evaluated as pH-sensitive agents for targeting of acidic tissue and pH-dependent cytoplasmic delivery of molecules. Biophysical studies revealed the molecular mechanism of peptides action and localization within the lipid bilayer of the membrane at high and low pHs. The symmetric, c[(WE)4WC], and asymmetric, c[E4W5C], cyclic peptides translocated amanitin, a polar cargo molecule of similar size, across the lipid bilayer and induced cell death in a pH- and concentration-dependent manner. Fluorescently-labelled peptides were evaluated for targeting of acidic 4T1 mammary tumors in mice. The highest tumor to muscle ratio (5.6) was established for asymmetric cyclic peptide, c[E4W5C], at 24 hours after intravenous administration. pH-insensitive cyclic peptide c[R4W5C], where glutamic acid residues (E) were replaced by positively charged arginine residues (R), did not exhibit tumor targeting. We have introduced a novel class of cyclic peptides, which can be utilized as a new pH-sensitive tool in investigation or targeting of acidic tissue. PMID:27515582
Visualization of cyclic nucleotide dynamics in neurons
Gorshkov, Kirill; Zhang, Jin
2014-01-01
The second messengers cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) transduce many neuromodulatory signals from hormones and neurotransmitters into specific functional outputs. Their production, degradation and signaling are spatiotemporally regulated to achieve high specificity in signal transduction. The development of genetically encodable fluorescent biosensors has provided researchers with useful tools to study these versatile second messengers and their downstream effectors with unparalleled spatial and temporal resolution in cultured cells and living animals. In this review, we introduce the general design of these fluorescent biosensors and describe several of them in more detail. Then we discuss a few examples of using cyclic nucleotide fluorescent biosensors to study regulation of neuronal function and finish with a discussion of advances in the field. Although there has been significant progress made in understanding how the specific signaling of cyclic nucleotide second messengers is achieved, the mechanistic details in complex cell types like neurons are only just beginning to surface. Current and future fluorescent protein reporters will be essential to elucidate the role of cyclic nucleotide signaling dynamics in the functions of individual neurons and their networks. PMID:25538560
Further studies on cyclic erythropoiesis in mice
Gibson, C.M.; Gurney, C.W.; Simmons, E.L.; Gaston, E.O.
1985-10-01
When young adult female W/Wv mice are given 0.5 micro+Ci /sup 89/Sr/g body weight intravenously, their hematocrit values oscillate from nadirs of 26% to zeniths of 42% with a periodicity of 16 days. The response of the W/Wv mouse to an assortment of radioactive and hematologic stresses have been examined in an effort to understand better the pathophysiology of cyclic erythropoiesis. When the dose of /sup 89/Sr is increased, the amplitude of cycling increases as nadirs are lowered, but periodicity is unchanged. When the dose of /sup 89/Sr is lowered to 0.3 microCi or less, cyclic erythropoiesis of substantial amplitude is observed only after five or six microoscillations. A single hematopoietic insult of 80 rad x-irradiation coupled with phlebotomy produces a transient form of cyclic erythropoiesis, namely, a series of dampened oscillations prior to recovery. Finally, we report that Wv/Wv mice exhibit a form of cyclic erythropoiesis in response to 0.5 microCi /sup 89/Sr/g body weight, in which the hematocrit values of successive nadirs gradually increase, and stabilize at about 100 days. /sup 89/Sr does not induce cyclic erythropoiesis in the +/+, W/+, or W/v/+ mice, the Hertwig strain of anemic mice, or in normal BDF1 mice.
Quantacell: powerful charging of quantum batteries
NASA Astrophysics Data System (ADS)
Binder, Felix C.; Vinjanampathy, Sai; Modi, Kavan; Goold, John
2015-07-01
We study the problem of charging a quantum battery in finite time. We demonstrate an analytical optimal protocol for the case of a single qubit. Extending this analysis to an array of N qubits, we demonstrate that an N-fold advantage in power per qubit can be achieved when global operations are permitted. The exemplary analytic argument for this quantum advantage in the charging power is backed up by numerical analysis using optimal control techniques. It is demonstrated that the quantum advantage for power holds when, with cyclic operation in mind, initial and final states are required to be separable.
NASA Astrophysics Data System (ADS)
Georgescu, I. M.; Ashhab, S.; Nori, Franco
2014-01-01
Simulating quantum mechanics is known to be a difficult computational problem, especially when dealing with large systems. However, this difficulty may be overcome by using some controllable quantum system to study another less controllable or accessible quantum system, i.e., quantum simulation. Quantum simulation promises to have applications in the study of many problems in, e.g., condensed-matter physics, high-energy physics, atomic physics, quantum chemistry, and cosmology. Quantum simulation could be implemented using quantum computers, but also with simpler, analog devices that would require less control, and therefore, would be easier to construct. A number of quantum systems such as neutral atoms, ions, polar molecules, electrons in semiconductors, superconducting circuits, nuclear spins, and photons have been proposed as quantum simulators. This review outlines the main theoretical and experimental aspects of quantum simulation and emphasizes some of the challenges and promises of this fast-growing field.
Cyclic and low temperature effects on microcircuits
NASA Technical Reports Server (NTRS)
Weissflug, V. A.; Sisul, E. V.
1977-01-01
Cyclic temperature and low temperature operating life tests, and pre-/post-life device evaluations were used to determine the degrading effects of thermal environments on microcircuit reliability. Low power transistor-transistor-logic gates and linear devices were included in each test group. Device metallization systems included aluminum metallization/aluminum wire, aluminum metallization/gold wire, and gold metallization/gold wire. Fewer than 2% electrical failures were observed during the cyclic and low temperature life tests and the post-life evaluations revealed approximately 2% bond pull failures. Reconstruction of aluminum die metallization was observed in all devices and the severity of the reconstruction appeared to be directly related to the magnitude of the temperature excursion. All types of bonds except the gold/gold bonds were weakened by exposure to repeated cyclic temperature stress.
Asymmetric catalytic aziridination of cyclic enones.
De Vincentiis, Francesco; Bencivenni, Giorgio; Pesciaioli, Fabio; Mazzanti, Andrea; Bartoli, Giuseppe; Galzerano, Patrizia; Melchiorre, Paolo
2010-07-01
The first catalytic method for the asymmetric aziridination of cyclic enones is described. The presented organocatalytic strategy is based on the use of an easily available organocatalyst that is able to convert a wide range of cyclic enones into the desired aziridines with very high enantiomeric purity and good chemical yield. Such a method may very well open up new opportunities to stereoselectively prepare complex chiral molecules that possess an indane moiety, a framework that is found in a large number of bioactive and pharmaceutically important molecules. PMID:20512797
Perturbations in bouncing and cyclic models
NASA Astrophysics Data System (ADS)
Biswas, Tirthabir; Mayes, Riley; Lattyak, Colleen
2016-03-01
Being able to reliably track perturbations across bounces and turnarounds in cyclic and bouncing cosmology lies at the heart of being able to compare the predictions of these models with the cosmic microwave background observations. This has been a challenging task due to the unknown nature of the physics involved during the bounce as well as the technical challenge of matching perturbations precisely between the expansion and contraction phases. In this paper, we present some general techniques (analytical and numerical) that can be applied to understand the physics of the fluctuations, especially those with "long" wavelengths, and apply our techniques to nonsingular cosmological models such as the bounce inflation and cyclic inflation.
Vasopressin treatment for cyclic antidepressant overdose.
Barry, James David; Durkovich, David W; Williams, Saralyn R
2006-07-01
Due to neurotransmitter reuptake inhibition, peripheral alpha receptor blocking effects, and sodium channel blockade, severe cyclic antidepressant poisoning may lead to intractable hypotension. We report a case of severe amitriptyline toxicity, with hypotension unresponsive to direct alpha receptor agonists after pH manipulation, but improved with intravenous vasopressin. Vasopressin use in the setting of cyclic antidepressant toxicity has not been previously reported. Vasopressin may be a beneficial agent in the treatment of recalcitrant hypotension associated with poisoning or overdose. The anecdotal nature of this report must be emphasized and the use of vasopressin requires further research to define efficacy, dose, and potential side effects. PMID:16798158
Generalized Coefficients for Hopf Cyclic Cohomology
NASA Astrophysics Data System (ADS)
Hassanzadeh, Mohammad; Kucerovsky, Dan; Rangipour, Bahram
2014-09-01
A category of coefficients for Hopf cyclic cohomology is defined. It is shown that this category has two proper subcategories of which the smallest one is the known category of stable anti Yetter-Drinfeld modules. The middle subcategory is comprised of those coefficients which satisfy a generalized SAYD condition depending on both the Hopf algebra and the (co)algebra in question. Some examples are introduced to show that these three categories are different. It is shown that all components of Hopf cyclic cohomology work well with the new coefficients we have defined.
Cyclical rectal bleeding in colorectal endometriosis.
Levitt, M D; Hodby, K J; van Merwyk, A J; Glancy, R J
1989-12-01
Three case reports of cyclical rectal bleeding in endometriosis affecting rectum and sigmoid colon emphasize the close relationship between such cyclical bleeding and intestinal endometriosis. The cause of bleeding, however, is still unclear. The predilection of endometriotic deposits for the outer layers of the bowel wall suggests that mucosal involvement is not a prerequisite for rectal bleeding. The frequent absence of identifiable intramural haemorrhage casts doubt on the premise that intestinal endometriotic deposits 'menstruate'. The cause may simply be a transient tear in normal mucosa due to swelling of an underlying endometriotic deposit at the time of menstruation. PMID:2597100
Quantum networks reveal quantum nonlocality.
Cavalcanti, Daniel; Almeida, Mafalda L; Scarani, Valerio; Acín, Antonio
2011-01-01
The results of local measurements on some composite quantum systems cannot be reproduced classically. This impossibility, known as quantum nonlocality, represents a milestone in the foundations of quantum theory. Quantum nonlocality is also a valuable resource for information-processing tasks, for example, quantum communication, quantum key distribution, quantum state estimation or randomness extraction. Still, deciding whether a quantum state is nonlocal remains a challenging problem. Here, we introduce a novel approach to this question: we study the nonlocal properties of quantum states when distributed and measured in networks. We show, using our framework, how any one-way entanglement distillable state leads to nonlocal correlations and prove that quantum nonlocality is a non-additive resource, which can be activated. There exist states, local at the single-copy level, that become nonlocal when taking several copies of them. Our results imply that the nonlocality of quantum states strongly depends on the measurement context. PMID:21304513
Cyclic unequal error protection codes constructed from cyclic codes of composite length
NASA Technical Reports Server (NTRS)
Lin, Shu
1987-01-01
The distance structure of cyclic codes of composite length was investigated. A lower bound on the minimum distance for this class of codes is derived. In many cases, the lower bound gives the true minimum distance of a code. Then the distance structure of the direct sum of two cyclic codes of composite length were investigated. It was shown that, under certain conditions, the direct-sum code provides two levels of error correcting capability, and hence is a two-level unequal error protection (UEP) code. Finally, a class of two-level UEP cyclic direct-sum codes and a decoding algorithm for a subclass of these codes are presented.
Stapp, H.P.
1988-12-01
Quantum ontologies are conceptions of the constitution of the universe that are compatible with quantum theory. The ontological orientation is contrasted to the pragmatic orientation of science, and reasons are given for considering quantum ontologies both within science, and in broader contexts. The principal quantum ontologies are described and evaluated. Invited paper at conference: Bell's Theorem, Quantum Theory, and Conceptions of the Universe, George Mason University, October 20-21, 1988. 16 refs.
An Experimental Test of Phonemic Cyclicity.
ERIC Educational Resources Information Center
Gierut, Judith A.
1996-01-01
Evaluates the principle of laryngeal-supralaryngeal cyclicity by manipulating the domain cycle and phase relationship of the cycle as independent variables and by monitoring longitudinally the order of emergent phonemic distinctions in the sound systems of seven children with phonological delays as the dependent variable. Findings are discussed.…
One pot solution synthesis of cyclic oligodeoxyribonucleotides.
Capobianco, M L; Carcuro, A; Tondelli, L; Garbesi, A; Bonora, G M
1990-01-01
Several cyclic oligodeoxynucleotides with different base composition and size have been prepared from 5',3'-unprotected linear precursors, using a bifunctional phosphorylating reagent. The final deprotected oligomers have been characterized by 1H- and 31P-NMR. The present procedure is particularly useful for millimolar scale syntheses. PMID:2339055
One pot solution synthesis of cyclic oligodeoxyribonucleotides.
Capobianco, M L; Carcuro, A; Tondelli, L; Garbesi, A; Bonora, G M
1990-05-11
Several cyclic oligodeoxynucleotides with different base composition and size have been prepared from 5',3'-unprotected linear precursors, using a bifunctional phosphorylating reagent. The final deprotected oligomers have been characterized by 1H- and 31P-NMR. The present procedure is particularly useful for millimolar scale syntheses. PMID:2339055
Cyclic Cratonic Carbonates and Phanerozoic Calcite Seas.
ERIC Educational Resources Information Center
Wilkinson, Bruce H.
1982-01-01
Discusses causes of cyclicity in cratonic carbonate sequences and evidence for and potential significance of postulated primary calcite sediment components in past Paleozoic seas, outlining problems, focusing on models explaining existing data, and identifying background. Future sedimentary geologists will need to address these and related areas…
Quantum Computer Games: Quantum Minesweeper
ERIC Educational Resources Information Center
Gordon, Michal; Gordon, Goren
2010-01-01
The computer game of quantum minesweeper is introduced as a quantum extension of the well-known classical minesweeper. Its main objective is to teach the unique concepts of quantum mechanics in a fun way. Quantum minesweeper demonstrates the effects of superposition, entanglement and their non-local characteristics. While in the classical…
The geometric phase in quantum physics
Bohm, A.
1993-03-01
After an explanatory introduction, a quantum system in a classical time-dependent environment is discussed; an example is a magnetic moment in a classical magnetic field. At first, the general abelian case is discussed in the adiabatic approximation. Then the geometric phase for nonadiabatic change of the environment (Anandan--Aharonov phase) is introduced, and after that general cyclic (nonadiabatic) evolution is discussed. The mathematics of fiber bundles is introduced, and some of its results are used to describe the relation between the adiabatic Berry phase and the geometric phase for general cyclic evolution of a pure state. The discussion is restricted to the abelian, U(1) phase.
Cyclic hardening in copper described in terms of combined monotonic and cyclic stress-strain curves
Chandler, H.D. . School of Mechanical Engineering)
1995-01-01
Hardening of polycrystalline copper subjected to tension-compression loading cycles in the plastic region is discussed with reference to changes in flow stress determined from equations describing dislocation glide. It is suggested that hardening is as a result of the accumulation of strain on a monotonic stress-strain curve. On initial loading, the behavior is monotonic. On stress reversal, a characteristic cyclic stress-strain curve is followed until the stress reaches a value in reverse loading corresponding to the maximum attained during the preceding half cycle. Thereafter, the monotonic path is followed until strain reversal occurs at completion of the half cycle. Repetition of the process results in cyclic hardening. Steady state cyclic behavior is reached when a stress associated with the monotonic stress-strain curve is reached which is equal to the stress associated with the cyclic stress-strain curve corresponding to the imposed strain amplitude.
Qasim, M; Fredrickson, H; McGrath, C; Furey, J; Bajpai, R
2005-06-01
Analysis of environmental degradation pathways of contaminants is aided by predictions of likely reaction mechanisms and intermediate products derived from computational models of molecular structure. Quantum mechanical methods and force-field molecular mechanics were used to characterize cyclic nitramines. Likely degradation mechanisms for hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) include hydroxylation utilizing addition of hydroxide ions to initiate proton abstraction via 2nd order rate elimination (E2) or via nucleophilic substitution of nitro groups, reductive chemical and biochemical degradation, and free radical oxidation. Due to structural similarities, it is predicted that, under homologous circumstances, certain RDX environmental degradation pathways should also be effective for octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX) and similar cyclic nitramines. Computational models provided a theoretical framework whereby likely transformation mechanisms and transformation products of cyclic nitramines were predicted and used to elucidate in situ degradation pathways. PMID:15804809
NASA Astrophysics Data System (ADS)
Pfeiffer, P.; Egusquiza, I. L.; di Ventra, M.; Sanz, M.; Solano, E.
2016-07-01
Technology based on memristors, resistors with memory whose resistance depends on the history of the crossing charges, has lately enhanced the classical paradigm of computation with neuromorphic architectures. However, in contrast to the known quantized models of passive circuit elements, such as inductors, capacitors or resistors, the design and realization of a quantum memristor is still missing. Here, we introduce the concept of a quantum memristor as a quantum dissipative device, whose decoherence mechanism is controlled by a continuous-measurement feedback scheme, which accounts for the memory. Indeed, we provide numerical simulations showing that memory effects actually persist in the quantum regime. Our quantization method, specifically designed for superconducting circuits, may be extended to other quantum platforms, allowing for memristor-type constructions in different quantum technologies. The proposed quantum memristor is then a building block for neuromorphic quantum computation and quantum simulations of non-Markovian systems.
Pfeiffer, P; Egusquiza, I L; Di Ventra, M; Sanz, M; Solano, E
2016-01-01
Technology based on memristors, resistors with memory whose resistance depends on the history of the crossing charges, has lately enhanced the classical paradigm of computation with neuromorphic architectures. However, in contrast to the known quantized models of passive circuit elements, such as inductors, capacitors or resistors, the design and realization of a quantum memristor is still missing. Here, we introduce the concept of a quantum memristor as a quantum dissipative device, whose decoherence mechanism is controlled by a continuous-measurement feedback scheme, which accounts for the memory. Indeed, we provide numerical simulations showing that memory effects actually persist in the quantum regime. Our quantization method, specifically designed for superconducting circuits, may be extended to other quantum platforms, allowing for memristor-type constructions in different quantum technologies. The proposed quantum memristor is then a building block for neuromorphic quantum computation and quantum simulations of non-Markovian systems. PMID:27381511
Pfeiffer, P.; Egusquiza, I. L.; Di Ventra, M.; Sanz, M.; Solano, E.
2016-01-01
Technology based on memristors, resistors with memory whose resistance depends on the history of the crossing charges, has lately enhanced the classical paradigm of computation with neuromorphic architectures. However, in contrast to the known quantized models of passive circuit elements, such as inductors, capacitors or resistors, the design and realization of a quantum memristor is still missing. Here, we introduce the concept of a quantum memristor as a quantum dissipative device, whose decoherence mechanism is controlled by a continuous-measurement feedback scheme, which accounts for the memory. Indeed, we provide numerical simulations showing that memory effects actually persist in the quantum regime. Our quantization method, specifically designed for superconducting circuits, may be extended to other quantum platforms, allowing for memristor-type constructions in different quantum technologies. The proposed quantum memristor is then a building block for neuromorphic quantum computation and quantum simulations of non-Markovian systems. PMID:27381511
NASA Astrophysics Data System (ADS)
Spring, Joseph
2009-04-01
We explore possible characterisations of entanglement classes which may be interpreted as gates acting on globally distributed systems. The cyclic nature of a selection of entanglement gates, primitives, is explored commencing with gates for generating Bell, GHZ and W states.
Quantum model of light transmission in array waveguide gratings.
Capmany, J; Mora, J; Fernández-Pousa, C R; Muñoz, P
2013-06-17
We develop, to the best of our knowledge, the first model for an array waveguide grating (AWG) device subject to quantum inputs and analyze its basic transformation functionalities for single-photon states. A commercial, cyclic AWG is experimentally characterized with weak input coherent states as a means of exploring its behaviour under realistic quantum detection. In particular it is shown the existence of a cutoff value of the average photon number below which quantum crosstalk between AWG ports is negligible with respect to dark counts. These results can be useful when considering the application of AWG devices to integrated quantum photonic systems. PMID:23787671
40 CFR 721.3440 - Haloalkyl substituted cyclic ethers.
Code of Federal Regulations, 2010 CFR
2010-07-01
... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Haloalkyl substituted cyclic ethers... Substances § 721.3440 Haloalkyl substituted cyclic ethers. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substances haloalkyl substituted cyclic ethers (PMN P-85-368 and...
40 CFR 721.3440 - Haloalkyl substituted cyclic ethers.
Code of Federal Regulations, 2011 CFR
2011-07-01
... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Haloalkyl substituted cyclic ethers... Substances § 721.3440 Haloalkyl substituted cyclic ethers. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substances haloalkyl substituted cyclic ethers (PMN P-85-368 and...
Synthesis of cyclic sulfones by ring-closing metathesis.
Yao, Qingwei
2002-02-01
A general and highly efficient synthesis of cyclic sulfones based on ring-closing metathesis has been developed. The synthetic utility of the resulting cyclic sulfones was demonstrated by their participation in stereoselective Diels-Alder reactions and transformation to cyclic dienes by the Ramberg-Bäcklund reaction. PMID:11820896
Cyclic debonding of adhesively bonded composites
NASA Technical Reports Server (NTRS)
Mall, S.; Johnson, W. S.; Everett, R. A., Jr.
1982-01-01
The fatigue behavior of a simple composite to composite bonded joint was analyzed. The cracked lap shear specimen subjected to constant amplitude cyclic loading was studied. Two specimen geometries were tested for each bonded system: (1) a strap adherend of 16 plies bonded to a lap adherend of 8 plies; and (2) a strap adherend of 8 plies bonded to a lap adherend of 16 plies. In all specimens the fatigue failure was in the form of cyclic debonding with some 0 deg fiber pull off from the strap adherend. The debond always grew in the region of adhesive that had the highest mode (peel) loading and that region was close to the adhesive strap interface.
Separation of isotopes by cyclical processes
Hamrin, Jr., Charles E.; Weaver, Kenny
1976-11-02
Various isotopes of hydrogen are separated by a cyclic sorption process in which a gas stream containing the isotopes is periodically passed through a high pressure column containing a palladium sorbent. A portion of the product from the high pressure column is passed through a second column at lower pressure to act as a purge. Before the sorbent in the high pressure column becomes saturated, the sequence is reversed with the stream flowing through the former low-pressure column now at high pressure, and a portion of the product purging the former high pressure column now at low pressure. The sequence is continued in cyclic manner with the product being enriched in a particular isotope.
Combustion oscillation control by cyclic fuel injection
Richards, G.A.; Yip, M.J.; Robey, E.; Cowell, L.; Rawlins, D.
1995-04-01
A number of recent articles have demonstrated the use of active control to mitigate the effects of combustion instability in afterburner and dump combustor applications. In these applications, cyclic injection of small quantities of control fuel has been proposed to counteract the periodic heat release that contributes to undesired pressure oscillations. This same technique may also be useful to mitigate oscillations in gas turbine combustors, especially in test rig combustors characterized by acoustic modes that do not exist in the final engine configuration. To address this issue, the present paper reports on active control of a subscale, atmospheric pressure nozzle/combustor arrangement. The fuel is natural gas. Cyclic injection of 14% control fuel in a premix fuel nozzle is shown to reduce oscillating pressure amplitude by a factor of 0.30 (i.e., {approximately}10 dB) at 300 Hz. Measurement of the oscillating heat release is also reported.
Universal Cyclic Topology in Polymer Networks.
Wang, Rui; Alexander-Katz, Alfredo; Johnson, Jeremiah A; Olsen, Bradley D
2016-05-01
Polymer networks invariably possess topological defects: loops of different orders which have profound effects on network properties. Here, we demonstrate that all cyclic topologies are a universal function of a single dimensionless parameter characterizing the conditions for network formation. The theory is in excellent agreement with both experimental measurements of hydrogel loop fractions and Monte Carlo simulations without any fitting parameters. We demonstrate the superposition of the dilution effect and chain-length effect on loop formation. The one-to-one correspondence between the network topology and primary loop fraction demonstrates that the entire network topology is characterized by measurement of just primary loops, a single chain topological feature. Different cyclic defects cannot vary independently, in contrast to the intuition that the densities of all topological species are freely adjustable. Quantifying these defects facilitates studying the correlations between the topology and properties of polymer networks, providing a key step in overcoming an outstanding challenge in polymer physics. PMID:27203346
Cyclic nucleotide signalling in kidney fibrosis
Schinner, Elisabeth; Wetzl, Veronika; Schlossmann, Jens
2015-01-01
Kidney fibrosis is an important factor for the progression of kidney diseases, e.g., diabetes mellitus induced kidney failure, glomerulosclerosis and nephritis resulting in chronic kidney disease or end-stage renal disease. Cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) were implicated to suppress several of the above mentioned renal diseases. In this review article, identified effects and mechanisms of cGMP and cAMP regarding renal fibrosis are summarized. These mechanisms include several signalling pathways of nitric oxide/ANP/guanylyl cyclases/cGMP-dependent protein kinase and cAMP/Epac/adenylyl cyclases/cAMP-dependent protein kinase. Furthermore, diverse possible drugs activating these pathways are discussed. From these diverse mechanisms it is expected that new pharmacological treatments will evolve for the therapy or even prevention of kidney failure. PMID:25622251
Cyclic ethers adsorbed on Ru(001)
NASA Astrophysics Data System (ADS)
Walczak, M. M.; Thiel, P. A.
1990-11-01
The three cyclic ethers 1,3-dioxane. 1,4-dioxane and 1,3,5-trioxane all exhibit multiple desorption states from Ru(001) between 200 and 310 K, in addition to the multilayer and metastable states at lower temperature. Most distinctive are the two low-temperature α-states. which are similar in shape, position, and relative population for all three compounds. This suggests that these states are associated with configurations which are accessible to all three molecules. The data also indicate that there is some molecular decomposition to gaseous CO and H 2. 1,4-Dioxane yields the largest amounts of these decomposition products, suggesting that this molecule is most susceptible to surface-catalyzed decomposition. The desorption data for the three cyclic ethers are grossly similar to each other, and also to the straight-chain diethers which we have previously studied.
Combustion oscillation control by cyclic fuel injection
Richards, G.A.; Yip, M.J.; Robey, E.; Cowell, L.; Rawlins, D.
1997-04-01
A number of recent articles have demonstrated the use of active control to mitigate the effects of combustion instability in afterburner and dump combustor applications. In these applications, cyclic injection of small quantities of control fuel has been proposed to counteract the periodic heat release that contributes to undesired pressure oscillations. This same technique may also be useful to mitigate oscillations in gas turbine combustors, especially in test rig combustors characterized by acoustic modes that do not exist in the final engine configuration. To address this issue, the present paper reports on active control of a subscale, atmospheric pressure nozzle.combustor arrangement. The fuel is natural gas. Cyclic injection of 14 percent control fuel in a premix fuel nozzle is shown to reduce oscillating pressure amplitude by a factor of 0.30 (i.e., {minus}10 dB) at 300 Hz. Measurement of the oscillating heat release is also reported.
Cyclic Oxidation Modeling and Life Prediction
NASA Technical Reports Server (NTRS)
Smialek, James L.
2004-01-01
The cyclic oxidation process can be described as an iterative scale growth and spallation sequence by a number of similar models. Model input variable include oxide scale type and growth parameters, spalling geometry, spall constant, and cycle duration. Outputs include net weight change, the amounts of retained and spalled oxide, the total oxygen and metal consumed, and the terminal rates of weight loss and metal consumption. All models and their variations produce a number of similar characteristic features. In general, spalling and material consumption increase to a steady state rate, at which point the retained scale approaches a constant and the rate of weight loss becomes linear. For one model, this regularity was demonstrated as dimensionless, universal expressions, obtained by normalizing the variables by critical performance factors. These insights were enabled through the use of the COSP for Windows cyclic oxidation spalling program.
Universal Cyclic Topology in Polymer Networks
NASA Astrophysics Data System (ADS)
Wang, Rui; Alexander-Katz, Alfredo; Johnson, Jeremiah A.; Olsen, Bradley D.
2016-05-01
Polymer networks invariably possess topological defects: loops of different orders which have profound effects on network properties. Here, we demonstrate that all cyclic topologies are a universal function of a single dimensionless parameter characterizing the conditions for network formation. The theory is in excellent agreement with both experimental measurements of hydrogel loop fractions and Monte Carlo simulations without any fitting parameters. We demonstrate the superposition of the dilution effect and chain-length effect on loop formation. The one-to-one correspondence between the network topology and primary loop fraction demonstrates that the entire network topology is characterized by measurement of just primary loops, a single chain topological feature. Different cyclic defects cannot vary independently, in contrast to the intuition that the densities of all topological species are freely adjustable. Quantifying these defects facilitates studying the correlations between the topology and properties of polymer networks, providing a key step in overcoming an outstanding challenge in polymer physics.
Canine infectious cyclic thrombocytopenia found in Taiwan.
Chang, A C; Chang, W L; Lin, C T; Pan, M J; Lee, S C
1996-05-01
Here were report the first canine infectious cyclic thrombocytopenia (CICT) found in Taiwan. Platelet-specific inclusions were detected in the blood smear of a military working dog. To identify the etiologic agent, the patient's blood was transmitted to three six-month-old German Shepherd dogs. The Ehrlichia platys-like inclusions were observed six to eight days after inoculation. Indirect fluorescent antibody test showed that the serum from the patient reacted specifically with the microorganisms within the platelets. Typical hematologic manifestations of E. platys infection, cyclic parasitemia and concomitant thrombocytopenia, were observed in these dogs. The prevalence of CICT in north Taiwan was also studied, and the incidence was 8.9% (4 out of 45) in civilian dogs and 97.1% (34 out of 35) in dogs from a heavily tick infested kennel. PMID:8741613
Quantum hair and quantum gravity
Coleman, S. ); Krauss, L.M. ); Preskill, J. ); Wilczek, F. )
1992-01-01
A black hole may carry quantum numbers that are not associated with massless gauge fields, contrary to the spirit of the 'no-hair' theorems. The 'quantum hair' is invisible in the classical limit, but measurable via quantum interference experiments. Quantum hair alters the temperature of the radiation emitted by a black hole. It also induces non-zero expectation values for fields outside the event horizon; these expectation values are non-perturbative in [Dirac h], and decay exponentially far from the hole. The existence of quantum hair demonstrates that a black hole can have an intricate quantum-mechanical structure that is completely missed by standard semiclassical theory.
Quantum robots and quantum computers
Benioff, P.
1998-07-01
Validation of a presumably universal theory, such as quantum mechanics, requires a quantum mechanical description of systems that carry out theoretical calculations and systems that carry out experiments. The description of quantum computers is under active development. No description of systems to carry out experiments has been given. A small step in this direction is taken here by giving a description of quantum robots as mobile systems with on board quantum computers that interact with different environments. Some properties of these systems are discussed. A specific model based on the literature descriptions of quantum Turing machines is presented.
Zurek, Wojciech H
2008-01-01
Quantum Darwinism - proliferation, in the environment, of multiple records of selected states of the system (its information-theoretic progeny) - explains how quantum fragility of individual state can lead to classical robustness of their multitude.
NASA Astrophysics Data System (ADS)
Harju, Antti J.
2016-06-01
This is a study of orbifold-quotients of quantum groups (quantum orbifolds {Θ } rightrightarrows Gq). These structures have been studied extensively in the case of the quantum S U 2 group. A generalized theory of quantum orbifolds over compact simple and simply connected quantum groups is developed. Associated with a quantum orbifold there is an invariant subalgebra and a crossed product algebra. For each spin quantum orbifold, there is a unitary equivalence class of Dirac spectral triples over the invariant subalgebra, and for each effective spin quantum orbifold associated with a finite group action, there is a unitary equivalence class of Dirac spectral triples over the crossed product algebra. A Hopf-equivariant Fredholm index problem is studied as an application.
Pfeiffer, P.; Egusquiza, I. L.; Di Ventra, M.; Sanz, M.; Solano, E.
2016-07-06
Technology based on memristors, resistors with memory whose resistance depends on the history of the crossing charges, has lately enhanced the classical paradigm of computation with neuromorphic architectures. However, in contrast to the known quantized models of passive circuit elements, such as inductors, capacitors or resistors, the design and realization of a quantum memristor is still missing. Here, we introduce the concept of a quantum memristor as a quantum dissipative device, whose decoherence mechanism is controlled by a continuous-measurement feedback scheme, which accounts for the memory. Indeed, we provide numerical simulations showing that memory effects actually persist in the quantummore » regime. Our quantization method, specifically designed for superconducting circuits, may be extended to other quantum platforms, allowing for memristor-type constructions in different quantum technologies. As a result, the proposed quantum memristor is then a building block for neuromorphic quantum computation and quantum simulations of non-Markovian systems.« less
[Cyclic esotropia (alternate day squint) (author's transl)].
Aichmair, H
1977-02-10
One case of the extremely rare conditioning of cyclic esotropia is reported following a short review of the literature and clinical features of this form of strabism. According to our experience the only effective treatment is operative correction on the day of the squint. It is not advisable to wait until the alternate day squint cycle breaks down and a permanent convergent squint develops. PMID:836616
Asymmetric Redox-Annulation of Cyclic Amines
2015-01-01
Cyclic amines such as 1,2,3,4-tetrahydroisoquinoline undergo regiodivergent annulation reactions with 4-nitrobutyraldehydes. These redox-neutral transformations enable the asymmetric synthesis of highly substituted polycyclic ring systems in just two steps from commercial materials. The utility of this process is illustrated in a rapid synthesis of (−)-protoemetinol. Computational studies provide mechanistic insights and implicate the elimination of acetic acid from an ammonium nitronate intermediate as the rate-determining step. PMID:26348653
Cyclic nucleotide phosphodiesterase 1 and vascular aging.
Yan, Chen
2015-12-01
VSMCs (vascular smooth muscle cells) play critical roles in arterial remodelling with aging, hypertension and atherosclerosis. VSMCs exist in diverse phenotypes and exhibit phenotypic plasticity, e.g. changing from a quiescent/contractile phenotype to an active myofibroblast-like, often called 'synthetic', phenotype. Synthetic VSMCs are able to proliferate, migrate and secrete ECM (extracellular matrix) proteinases and ECM proteins. In addition, they produce pro-inflammatory molecules, providing an inflammatory microenvironment for leucocyte penetration, accumulation and activation. The aging VSMCs have also shown changes in cellular phenotype, responsiveness to contracting and relaxing mediators, replicating potential, matrix synthesis, inflammatory mediators and intracellular signalling. VSMC dysfunction plays a key role in age-associated vascular remodelling. Cyclic nucleotide PDEs (phosphodiesterases), by catalysing cyclic nucleotide hydrolysis, play a critical role in regulating the amplitude, duration and compartmentalization of cyclic nucleotide signalling. Abnormal alterations of PDEs and subsequent changes in cyclic nucleotide homoeostasis have been implicated in a number of different diseases. In the study published in the latest issue of Clinical Science, Bautista Niño and colleagues have shown that, in cultured senescent human VSMCs, PDE1A and PDE1C mRNA levels are significantly up-regulated and inhibition of PDE1 activity with vinpocetine reduced cellular senescent makers in senescent VSMCs. Moreover, in the premature aging mice with genomic instability (Ercc1(d/-)), impaired aortic ring relaxation in response to SNP (sodium nitroprusside), an NO (nitric oxide) donor, was also largely improved by vinpocetine. More interestingly, using data from human GWAS (genome-wide association studies), it has been found that PDE1A single nucleotide polymorphisms is significantly associated with diastolic blood pressure and carotid intima-media thickening, two
Cyclic energy harvesting from pyroelectric materials.
Mane, Poorna; Xie, Jingsi; Leang, Kam K; Mossi, Karla
2011-01-01
A method of continuously harvesting energy from pyroelectric materials is demonstrated using an innovative cyclic heating scheme. In traditional pyroelectric energy harvesting methods, static heating sources are used, and most of the available energy has to be harvested at once. A cyclic heating system is developed such that the temperature varies between hot and cold regions. Although the energy harvested during each period of the heating cycle is small, the accumulated total energy over time may exceed traditional methods. Three materials are studied: a commonly available soft lead zirconate titanate (PZT), a pre-stressed PZT composite, and single-crystal PMN-30PT. Radiation heating and natural cooling are used such that, at smaller cyclic frequencies, the temporal rate of change in temperature is large enough to produce high power densities. The maximum power density of 8.64 μW/cm3 is generated with a PMN-30PT single crystal at an angular velocity of 0.64 rad/s with a rate of 8.5°C/s. The pre-stressed PZT composite generated a power density of 6.31 μW/cm(3), which is 40% larger than the density of 4.48 μW/cm3 obtained from standard PZT. PMID:21244970
High-affinity Cyclic Peptide Matriptase Inhibitors*
Quimbar, Pedro; Malik, Uru; Sommerhoff, Christian P.; Kaas, Quentin; Chan, Lai Y.; Huang, Yen-Hua; Grundhuber, Maresa; Dunse, Kerry; Craik, David J.; Anderson, Marilyn A.; Daly, Norelle L.
2013-01-01
The type II transmembrane serine protease matriptase is a key activator of multiple signaling pathways associated with cell proliferation and modification of the extracellular matrix. Deregulated matriptase activity correlates with a number of diseases, including cancer and hence highly selective matriptase inhibitors may have therapeutic potential. The plant-derived cyclic peptide, sunflower trypsin inhibitor-1 (SFTI-1), is a promising drug scaffold with potent matriptase inhibitory activity. In the current study we have analyzed the structure-activity relationships of SFTI-1 and Momordica cochinchinensis trypsin inhibitor-II (MCoTI-II), a structurally divergent trypsin inhibitor from Momordica cochinchinensis that also contains a cyclic backbone. We show that MCoTI-II is a significantly more potent matriptase inhibitor than SFTI-1 and that all alanine mutants of both peptides, generated using positional scanning mutagenesis, have decreased trypsin affinity, whereas several mutations either maintain or result in enhanced matriptase inhibitory activity. These intriguing results were used to design one of the most potent matriptase inhibitors known to date with a 290 pm equilibrium dissociation constant, and provide the first indication on how to modulate affinity for matriptase over trypsin in cyclic peptides. This information might be useful for the design of more selective and therapeutically relevant inhibitors of matriptase. PMID:23548907
Cyclic dominance in evolutionary games: a review
Szolnoki, Attila; Mobilia, Mauro; Jiang, Luo-Luo; Szczesny, Bartosz; Rucklidge, Alastair M.; Perc, Matjaž
2014-01-01
Rock is wrapped by paper, paper is cut by scissors and scissors are crushed by rock. This simple game is popular among children and adults to decide on trivial disputes that have no obvious winner, but cyclic dominance is also at the heart of predator–prey interactions, the mating strategy of side-blotched lizards, the overgrowth of marine sessile organisms and competition in microbial populations. Cyclical interactions also emerge spontaneously in evolutionary games entailing volunteering, reward, punishment, and in fact are common when the competing strategies are three or more, regardless of the particularities of the game. Here, we review recent advances on the rock–paper–scissors (RPS) and related evolutionary games, focusing, in particular, on pattern formation, the impact of mobility and the spontaneous emergence of cyclic dominance. We also review mean-field and zero-dimensional RPS models and the application of the complex Ginzburg–Landau equation, and we highlight the importance and usefulness of statistical physics for the successful study of large-scale ecological systems. Directions for future research, related, for example, to dynamical effects of coevolutionary rules and invasion reversals owing to multi-point interactions, are also outlined. PMID:25232048
Cyclic degassing of Erebus volcano, Antarctica
NASA Astrophysics Data System (ADS)
Ilanko, Tehnuka; Oppenheimer, Clive; Burgisser, Alain; Kyle, Philip
2015-06-01
Field observations have previously identified rapid cyclic changes in the behaviour of the lava lake of Erebus volcano. In order to understand more fully the nature and origins of these cycles, we present here a wavelet-based frequency analysis of time series measurements of gas emissions from the lava lake, obtained by open-path Fourier transform infrared spectroscopy. This reveals (i) a cyclic change in total gas column amount, a likely proxy for gas flux, with a period of about 10 min, and (ii) a similarly phased cyclic change in proportions of volcanic gases, which can be explained in terms of chemical equilibria and pressure-dependent solubilities. Notably, the wavelet analysis shows a persistent periodicity in the CO2/CO ratio and strong periodicity in H2O and SO2 degassing. The `peaks' of the cycles, defined by maxima in H2O and SO2 column amounts, coincide with high CO2/CO ratios and proportionally smaller increases in column amounts of CO2, CO, and OCS. We interpret the cycles to arise from recharge of the lake by intermittent pulses of magma from shallow depths, which degas H2O at low pressure, combined with a background gas flux that is decoupled from this very shallow magma degassing.
Cyclic viscoelastoplasticity of polypropylene/nanoclay composites
NASA Astrophysics Data System (ADS)
Drozdov, A. D.; deC. Christiansen, J.
2012-11-01
Observations are reported on isotactic polypropylene/organically modified nanoclay hybrids with concentrations of filler ranging from 0 to 5 wt.% in cyclic tensile tests with a stress-controlled program (oscillations between various maximum stresses and the zero minimum stress). A pronounced effect of nanofiller is demonstrated: reinforcement with 2 wt.% of clay results in strong reduction of maximum and minimum strains per cycle and growth of number of cycles to failure compared with neat polypropylene. To rationalize these findings, a constitutive model is developed in cyclic viscoelasticity and viscoplasticity of polymer nanocomposites. Adjustable parameters in the stress-strain relations are found by fitting experimental data. The model correctly describes the growth of the ratcheting strain and shows that fatigue failure is driven by a pronounced increase in plastic strain in the crystalline phase. To assess the influence of loading conditions on the changes in the material parameters, experimental data on polypropylene are studied in cyclic tests with a strain-controlled program (oscillations between fixed maximum and minimum strains) and a mixed program (oscillations between various maximum strains and the zero minimum stress). Numerical simulation confirms the ability of the model to predict the evolution of stress-strain diagrams with the number of cycles.
Cyclic steaming in heavy oil diatomite
Kumar, M.; Beatty, F.D.
1995-12-31
Chevron currently uses cyclic steaming as a recovery method to produce economically its heavy oil diatomite resource in the Cymric field, San Joaquin Valley, California. A highly instrumented, cyclically steaming well from this field was simulated in this study to delineate important production mechanisms, to optimize operations, and to improve reservoir management. The model was constrained, as much as possible, by the available measured data. Results show that fluid flow from the well to the reservoir is primarily through the hydraulic fracture induced by the injected steam. Parameters with unique importance to modeling cyclic steaming in diatomites are: (1) induced fracture dimension (length and height), (2) matrix permeability, (3) oil/water capillary pressure, (4) grid size perpendicular to fracture face, and (5) producing bottomhole pressures. Additionally, parameters important for conventional steam injection processes, such as relative permeabilities and injected steam volume, quality, and rate, are important for diatomites also. Oil production rates and steam/oil ratios calculated by this model compare reasonably with field data.
Cyclic dominance in evolutionary games: a review.
Szolnoki, Attila; Mobilia, Mauro; Jiang, Luo-Luo; Szczesny, Bartosz; Rucklidge, Alastair M; Perc, Matjaž
2014-11-01
Rock is wrapped by paper, paper is cut by scissors and scissors are crushed by rock. This simple game is popular among children and adults to decide on trivial disputes that have no obvious winner, but cyclic dominance is also at the heart of predator-prey interactions, the mating strategy of side-blotched lizards, the overgrowth of marine sessile organisms and competition in microbial populations. Cyclical interactions also emerge spontaneously in evolutionary games entailing volunteering, reward, punishment, and in fact are common when the competing strategies are three or more, regardless of the particularities of the game. Here, we review recent advances on the rock-paper-scissors (RPS) and related evolutionary games, focusing, in particular, on pattern formation, the impact of mobility and the spontaneous emergence of cyclic dominance. We also review mean-field and zero-dimensional RPS models and the application of the complex Ginzburg-Landau equation, and we highlight the importance and usefulness of statistical physics for the successful study of large-scale ecological systems. Directions for future research, related, for example, to dynamical effects of coevolutionary rules and invasion reversals owing to multi-point interactions, are also outlined. PMID:25232048
A criterion for lattice supersymmetry: cyclic Leibniz rule
NASA Astrophysics Data System (ADS)
Kato, Mitsuhiro; Sakamoto, Makoto; So, Hiroto
2013-05-01
It is old folklore that the violation of Leibniz rule on a lattice is an obstruction for constructing a lattice supersymmetric model. While it is still true for full supersymmetry, we show that a slightly modified form of the Leibniz rule, which we call cyclic Leibniz rule (CLR), is actually a criterion for the existence of partial lattice supersymmetry. In one dimension, we find sets of lattice difference operator and field multiplication smeared over lattice which satisfy the CLR under some natural assumptions such as translational invariance and locality. Thereby we construct a model of supersymmetric lattice quantum mechanics without spoiling locality. The CLR relation is coincident with the condition that the vanishing of the so-called surface term in the construction by lattice Nicolai map. We can construct superfield formalism with arbitrary superpotential. This also enables us to apply safely a localization technique to our model, because the kinetic term and the interaction terms of our model are independently invariant under the supersymmetry transformation. A preliminary attempt in finding a solution for the higher dimensional case is also discussed.
Cyclic steady state stress-strain behavior of UHMW polyethylene.
Krzypow, D J; Rimnac, C M
2000-10-01
To increase the long-term performance of total joint replacements, finite element analyses of ultra high molecular weight polyethylene (UHMWPE) components have been conducted to predict the effect of load on the stress and strain distributions occurring on and within these components. Early models incorporated the monotonic behavior of UHMWPE without considering the unloading and cyclic loading behavior. However, UHMWPE components undergo cyclic loading during use and at least two wear damage modes (pitting and delamination) are thought to be associated with the fatigue fracture properties of UHMWPE. The objective of this study was to examine the fully reversed uniaxial tension/compression cyclic steady state stress-strain behavior of UHMWPE as a first step towards developing a cyclic constitutive relationship for UHMWPE. The hypothesis that cycling results in a permanent change in the stress-strain relationship, that is, that the cyclic steady state represents a new cyclically stabilized state, was examined. It was found that, like other ductile polymers, UHMWPE substantially cyclically softens under fully reversed uniaxial straining. More cyclic softening occurred in tension than in compression. Furthermore, cyclic steady state was attained, but not cyclic stability. It is suggested that it may be more appropriate to base a material constitutive relationship for UHMWPE for finite element analyses of components upon a cyclically modified stress-strain relationship. PMID:10966018
NASA Astrophysics Data System (ADS)
Tran, Duc-Minh
2014-10-01
Reduced models of multi-stage cyclic structures such as bladed-disk assemblies are developed by using the multi-stage cyclic symmetry reduction and/or component mode synthesis methods. The multi-stage cyclic symmetry reduction consists in writing the equations of the bladed disks, the inter-disk structures, the inter-disk constraints and the whole multi-stage coupled system in terms of the traveling wave coordinates for all the phase indexes of the reference sectors and for all the bladed disks. Several reduced coupled systems are then solved by selecting at each time only one or a few phase indexes for each bladed disk and by applying the cyclic symmetry boundary conditions. On the other hand, component mode synthesis methods are used either independently or in combination with the multi-stage cyclic symmetry reduction to obtain reduced models of the multi-stage structure. Two of them are particularly efficient, that are firstly component mode synthesis methods with interface modes applied on the bladed disks and secondly component mode synthesis methods with traveling wave coordinates applied on the reference sectors.
The conformations of cyclic polymers in bidisperse blends of cyclic polymers
NASA Astrophysics Data System (ADS)
Lang, Michael
2013-03-01
The size of cyclic polymers in bidisperse blends of chemically identical molecules is analyzed by computer simulations. The compression of entangled rings can be explained by the changes in the penetrable fraction of the surface bounded by the ring. Corrections for small rings can be approximated by a concatenation probability 1 -POO that a cyclic polymer entraps at least one other cyclic polymer. Both results are in line with a previous work on the compression of entangled cyclic polymers in monodisperse melts. For entangled cyclic polymers, bond-bond correlations show a constant anti-correlation peak at a curvilinear distance of about ten segments that coincides with a horizontal tangent in the normalized mean square internal distances along the ring for sufficiently large degrees of polymerization. In consequence, the length scale of topological interactions must be considered as constant in contrast to a recent proposal by Sakaue. Our data is not in accord with an extension of the model of Cates and Deutsch to bidiperse blends of ring polymers.
NASA Astrophysics Data System (ADS)
Brown, Matthew J.
2014-02-01
The framework of quantum frames can help unravel some of the interpretive difficulties i the foundation of quantum mechanics. In this paper, I begin by tracing the origins of this concept in Bohr's discussion of quantum theory and his theory of complementarity. Engaging with various interpreters and followers of Bohr, I argue that the correct account of quantum frames must be extended beyond literal space-time reference frames to frames defined by relations between a quantum system and the exosystem or external physical frame, of which measurement contexts are a particularly important example. This approach provides superior solutions to key EPR-type measurement and locality paradoxes.
NASA Astrophysics Data System (ADS)
Moulick, Subhayan Roy; Panigrahi, Prasanta K.
2016-06-01
We propose the idea of a quantum cheque scheme, a cryptographic protocol in which any legitimate client of a trusted bank can issue a cheque, that cannot be counterfeited or altered in anyway, and can be verified by a bank or any of its branches. We formally define a quantum cheque and present the first unconditionally secure quantum cheque scheme and show it to be secure against any no-signalling adversary. The proposed quantum cheque scheme can been perceived as the quantum analog of Electronic Data Interchange, as an alternate for current e-Payment Gateways.
NASA Astrophysics Data System (ADS)
Moulick, Subhayan Roy; Panigrahi, Prasanta K.
2016-03-01
We propose the idea of a quantum cheque scheme, a cryptographic protocol in which any legitimate client of a trusted bank can issue a cheque, that cannot be counterfeited or altered in anyway, and can be verified by a bank or any of its branches. We formally define a quantum cheque and present the first unconditionally secure quantum cheque scheme and show it to be secure against any no-signalling adversary. The proposed quantum cheque scheme can been perceived as the quantum analog of Electronic Data Interchange, as an alternate for current e-Payment Gateways.
Average diagonal entropy in nonequilibrium isolated quantum systems.
Giraud, Olivier; García-Mata, Ignacio
2016-07-01
The diagonal entropy was introduced as a good entropy candidate especially for isolated quantum systems out of equilibrium. Here we present an analytical calculation of the average diagonal entropy for systems undergoing unitary evolution and an external perturbation in the form of a cyclic quench. We compare our analytical findings with numerical simulations of various quantum systems. Our calculations elucidate various heuristic relations proposed recently in the literature. PMID:27575092
Valentina, Stephanie; Ogawa, Takahiro; Nakazono, Kazuko; Aoki, Daisuke; Takata, Toshikazu
2016-06-20
High-yielding synthesis of cyclic block copolymer (CBC) using the rotaxane protocol by linear-cyclic polymer topology transformation was first demonstrated. Initial complexation of OH-terminated sec-ammonium salt and a crown ether was followed by the successive living ring-opening polymerizations of two lactones to a linear block copolymer having a rotaxane structure by the final capping of the propagation end. CBC was obtained in a high yield by an exploitation of the mechanical linkage through the translational movement of the rotaxane component to transform polymer structure from linear to cyclic. Furthermore, the change of the polymer topology was translated into a macroscopic change in crystallinity of the block copolymer. PMID:27037975
Inhibition of cyclic GMP-dependent protein kinase-mediated effects by (Rp)-8-bromo-PET-cyclic GMPS.
Butt, E.; Pöhler, D.; Genieser, H. G.; Huggins, J. P.; Bucher, B.
1995-01-01
1. The modulation of the guanosine 3':5'-cyclic monophosphate (cyclic GMP)- and adenosine 3':5'-cyclic monophosphate (cyclic AMP)-dependent protein kinase activities by the diastereomers of 8-bromo-beta phenyl-1, N2-ethenoguanosine 3':5'-cyclic monophosphorothioate, ((Rp)- and (Sp)-8-bromo-PET-cyclic GMPS) was investigated by use of purified protein kinases. In addition, the effects of (Rp)-8-bromo-PET-cyclic GMPS on protein phosphorylation in intact human platelets and on [3H]-noradrenaline release and neurogenic vasoconstriction in electrical field stimulated rat tail arteries were also studied. 2. Kinetic analysis with purified cyclic GMP-dependent protein kinase (PKG) type I alpha and I beta, which are expressed in the rat tail artery, revealed that (Rp)-8-bromo-PET-cyclic GMPS is a competitive inhibitor with an apparent Ki of 0.03 microM. The activation of purified cyclic AMP-dependent protein kinase (PKA) type II was antagonized with an apparent Ki of 10 microM. 3. In human platelets, (Rp)-8-bromo-PET-cyclic GMPS (0.1 mM) antagonized the activation of the PKG by the selective activator 8-(4-chlorophenylthio)-guanosine 3':5'-cyclic monophosphate (8-pCPT-cyclic GMP; 0.2 mM) without affecting the activation of PKA by (Sp)-5, 6-dichloro-1-beta-D-ribofurano-sylbenzimidazole- 3':5'-cyclic monophosphorothioate ((Sp)-5,6-DCl-cyclic BiMPS; 0.1 mM). 4. (Rp)-8-bromo-PET-cyclic GMPS was not hydrolysed by the cyclic GMP specific phosphodiesterase (PDE) type V from bovine aorta but potently inhibited this PDE. 5. The corresponding sulphur free cyclic nucleotide of the two studied phosphorothioate derivatives, 8-bromo-beta-phenyl-1, N2-ethenoguanosine-3':5'-cyclic monophosphate (8-bromo-PET-cyclic GMP), had no effect on electrically-induced [3H]-noradrenaline release but concentration-dependently decreased the stimulation-induced vasoconstriction. (Rp)-8-bromo-PET-cyclic GMPS (3 microM) shifted the vasoconstriction response to the right without affecting stimulation evoked
Cyclic AMP Receptor Protein-Aequorin Molecular Switch for Cyclic AMP
Scott, Daniel; Hamorsky, Krystal Teasley; Ensor, C. Mark; Anderson, Kimberly W.; Daunert, Sylvia
2011-01-01
Molecular switches are designer molecules that combine the functionality of two individual proteins into one, capable of manifesting an “on/off” signal in response to a stimulus. These switches have unique properties and functionalities and thus, can be employed as nanosensors in a variety of applications. To that end, we have developed a bioluminescent molecular switch for cyclic AMP. Bioluminescence offers many advantages over fluorescence and other detection methods including the fact that there is essentially zero background signal in physiological fluids, allowing for more sensitive detection and monitoring. The switch was created by combining the properties of the cyclic AMP receptor protein (CRP), a transcriptional regulatory protein from E. coli that binds selectively to cAMP with those of aequorin, a bioluminescent photoprotein native of the jellyfish Aequorea victoria. Genetic manipulation to split the genetic coding sequence of aequorin in two and genetically attach the fragments to the N and C termini of CRP, resulted in a hybrid protein molecular switch. The conformational change experienced by CRP upon the binding of cyclic AMP is suspected to result in the observed loss of bioluminescent signal from aequorin. The “on/off” bioluminescence can be modulated by cyclic AMP over a range of several orders of magnitude in a linear fashion in addition to the capacity to detect changes in cellular cyclic AMP of intact cells exposed to different external stimuli without the need to lyse the cells. We envision that the molecular switch could find applications in vitro as well as in vivo cyclic AMP detection and/or imaging. PMID:21329338
A classification of finite quantum kinematics
NASA Astrophysics Data System (ADS)
Tolar, J.
2014-10-01
Quantum mechanics in Hilbert spaces of finite dimension N is reviewed from the number theoretic point of view. For composite numbers N possible quantum kinematics are classified on the basis of Mackey's Imprimitivity Theorem for finite Abelian groups. This yields also a classification of finite Weyl-Heisenberg groups and the corresponding finite quantum kinematics. Simple number theory gets involved through the fundamental theorem describing all finite discrete Abelian groups of order N as direct products of cyclic groups, whose orders are powers of not necessarily distinct primes contained in the prime decomposition of N. The representation theoretic approach is further compared with the algebraic approach, where the basic object is the corresponding operator algebra. The consideration of fine gradings of this associative algebra then brings a fresh look on the relation between the mathematical formalism and physical realizations of finite quantum systems.
Universal quantum computation with unlabelled qubits
NASA Astrophysics Data System (ADS)
Severini, Simone
2006-06-01
We show that an nth root of the Walsh-Hadamard transform (obtained from the Hadamard gate and a cyclic permutation of the qubits), together with two diagonal matrices, namely a local qubit-flip (for a fixed but arbitrary qubit) and a non-local phase-flip (for a fixed but arbitrary coefficient), can do universal quantum computation on n qubits. A quantum computation, making use of n qubits and based on these operations, is then a word of variable length, but whose letters are always taken from an alphabet of cardinality three. Therefore, in contrast with other universal sets, no choice of qubit lines is needed for the application of the operations described here. A quantum algorithm based on this set can be interpreted as a discrete diffusion of a quantum particle on a de Bruijn graph, corrected on-the-fly by auxiliary modifications of the phases associated with the arcs.
Interactions of cyclic and non-cyclic naphthalene diimide derivatives with different nucleic acids.
Czerwinska, Izabella; Sato, Shinobu; Juskowiak, Bernard; Takenaka, Shigeori
2014-05-01
Recently, strategy based on stabilization of G-quadruplex telomeric DNA by small organic molecule has been realized by naphthalene diimide derivatives (NDIs). At the same time NDIs bind to DNA duplex as threading intercalators. Here we present cyclic derivative of naphthalene diimide (ligand 1) as DNA-binding ligand with ability to recognition of different structures of telomeric G-quadruplexes and ability to bis-intercalate to double-stranded helixes. The results have been compared to non-cyclic derivative (ligand 2) and revealed that preferential binding of ligands to nucleic acids strongly depends on their topology and structural features of ligands. PMID:24726302
Beć, Krzysztof B; Futami, Yoshisuke; Wójcik, Marek J; Nakajima, Takahito; Ozaki, Yukihiro
2016-08-11
Anharmonic vibrational analysis of near-infrared (NIR) spectra of acetic acid was carried out by anharmonic quantum chemical calculation in a wide concentration range of its CCl4 solution. By predicting vibrational spectra of acetic acid for the first time over a wide NIR region, it was possible to elucidate the influence of the formation of acetic acid cyclic dimer on its NIR spectrum. Quantum chemical simulations were based on coupled cluster and density functional theory quantum methods. Additionally, Møller-Plesset perturbation theory was employed for the additional calculation of hydrogen bonding stabilization energies. An anharmonic vibrational analysis was performed with the use of generalized second-order vibrational perturbation theory (GVPT2). A hybrid approach was assumed, in which monomeric species was treated by CCSD(T)/aug-cc-pVDZ (harmonic approximation) and B3LYP/SNSD (anharmonic approximation) methods. For the cyclic dimer, B3LYP and B2PLYP single and double hybrid functionals, paired with an SNSD basis set, were employed. DFT calculations were augmented with additional empirical dispersion correction. It was found that quantum chemically calculated vibrational modes in the NIR region are in a good agreement with experimental data. The results of anharmonic vibrational analysis were supported by a harmonic shift analysis, for elucidating the very strong anharmonic coupling observed between stretching modes of hydrogen bonded bridge in the cyclic dimer. However, the calculated wavenumbers for combination modes of double hydrogen bonded bridge in the cyclic dimer, which are very sensitive to the formation of hydrogen bonding, were found to be underestimated by quantum chemical methods. Therefore, by band fitting, the wavenumbers and shape parameters for these bands were found, and the modeled spectra were adjusted accordingly. A high accuracy of simulated spectra was achieved, and a detailed analysis of the experimental NIR spectra of acetic acid
Modelling water molecules inside cyclic peptide nanotubes
NASA Astrophysics Data System (ADS)
Tiangtrong, Prangsai; Thamwattana, Ngamta; Baowan, Duangkamon
2016-03-01
Cyclic peptide nanotubes occur during the self-assembly process of cyclic peptides. Due to the ease of synthesis and ability to control the properties of outer surface and inner diameter by manipulating the functional side chains and the number of amino acids, cyclic peptide nanotubes have attracted much interest from many research areas. A potential application of peptide nanotubes is their use as artificial transmembrane channels for transporting ions, biomolecules and waters into cells. Here, we use the Lennard-Jones potential and a continuum approach to study the interaction of a water molecule in a cyclo[(- D-Ala- L-Ala)_4-] peptide nanotube. Assuming that each unit of a nanotube comprises an inner and an outer tube and that a water molecule is made up of a sphere of two hydrogen atoms uniformly distributed over its surface and a single oxygen atom at the centre, we determine analytically the interaction energy of the water molecule and the peptide nanotube. Using this energy, we find that, independent of the number of peptide units, the water molecule will be accepted inside the nanotube. Once inside the nanotube, we show that a water molecule prefers to be off-axis, closer to the surface of the inner nanotube. Furthermore, our study of two water molecules inside the peptide nanotube supports the finding that water molecules form an array of a 1-2-1-2 file inside peptide nanotubes. The theoretical study presented here can facilitate thorough understanding of the behaviour of water molecules inside peptide nanotubes for applications, such as artificial transmembrane channels.
Cyclical konzo epidemics and climate variability.
Oluwole, Olusegun Steven A
2015-03-01
Konzo epidemics have occurred during droughts in the Democratic Republic of Congo (DR Congo) for >70 years, but also in Mozambique, Tanzania, and the Central African Republic. The illness is attributed to exposure to cyanide from cassava foods, on which the population depends almost exclusively during droughts. Production of cassava, a drought-resistant crop, has been shown to correlate with cyclical changes in precipitation in konzo-affected countries. Here we review the epidemiology of konzo as well as models of its pathogenesis. A spectral analysis of precipitation and konzo is performed to determine whether konzo epidemics are cyclical and whether there is spectral coherence. Time series of environmental temperature, precipitation, and konzo show cyclical changes. Periodicities of dominant frequencies in the spectra of precipitation and konzo range from 3 to 6 years in DR Congo. There is coherence of the spectra of precipitation and konzo. The magnitude squared coherence of 0.9 indicates a strong relationship between variability of climate and konzo epidemics. Thus, it appears that low precipitation phases of climate variability reduce the yield of food crops except cassava, upon which the population depends for supply of calories during droughts. Presence of very high concentrations of thiocyanate (SCN(-) ), the major metabolite of cyanide, in the bodily fluids of konzo subjects is a consequence of dietary exposure to cyanide, which follows intake of poorly processed cassava roots. Because cyanogens and minor metabolites of cyanide have not induced konzo-like illnesses, SCN(-) remains the most likely neurotoxicant of konzo. Public health control of konzo will require food and water programs during droughts. [Correction added on 26 February 2015, after first online publication: abstract reformatted per journal style] PMID:25523348
Universal Behavior of a Cyclic Oxidation Model
NASA Technical Reports Server (NTRS)
Smialek, James L.
2003-01-01
A mathematical model has been generated to represent the iterative, discrete growth and spallation processes associated with cyclic oxidation. Parabolic growth kinetics (k(sub p)) over and a constant spall area (F(sub A)) were assumed, with spalling occurring interfacially at the thickest regions of the scale. Although most models require numerical techniques, the regularity and simplicity of this progression permitted an approximation by algebraic expressions. Normalization could now be performed to reflect all parametric effects, and a universal cyclic oxidation response was generated: W(sub u) = 1/2 {3J(sub u)(sup 1/2)+ J(sub u)(sup 3/2)} where W, is weight change normalized by the maximum and J(sub u) is the cycle number normalized by the number to reach maximum. Similarly, the total amount of metal consumed was represented by a single normalized curve. The factor [(S(sub c)-l)(raised dot)sqrt(F(sub A)k(sub p)DELTAt)] was identified as a general figure of merit, where S(sub c) is the mass ratio of oxide to oxygen and DELTAt is the cycle duration. A cyclic oxidation failure map was constructed, in normalized k(sub p)-F(sub A) space, as defined by the locus of points corresponding to a critical amount of metal consumption in a given time. All three constructions describe behavior for every value of growth rate, spall fraction, and cycle duration by means of single curves, but with two branches corresponding to the times before and after steady state is achieved.
NASA Astrophysics Data System (ADS)
Steffen, Matthias
2013-03-01
Quantum mechanics plays a crucial role in many day-to-day products, and has been successfully used to explain a wide variety of observations in Physics. While some quantum effects such as tunneling limit the degree to which modern CMOS devices can be scaled to ever reducing dimensions, others may potentially be exploited to build an entirely new computing architecture: The quantum computer. In this talk I will review several basic concepts of a quantum computer. Why quantum computing and how do we do it? What is the status of several (but not all) approaches towards building a quantum computer, including IBM's approach using superconducting qubits? And what will it take to build a functional machine? The promise is that a quantum computer could solve certain interesting computational problems such as factoring using exponentially fewer computational steps than classical systems. Although the most sophisticated modern quantum computing experiments to date do not outperform simple classical computations, it is increasingly becoming clear that small scale demonstrations with as many as 100 qubits are beginning to be within reach over the next several years. Such a demonstration would undoubtedly be a thrilling feat, and usher in a new era of controllably testing quantum mechanics or quantum computing aspects. At the minimum, future demonstrations will shed much light on what lies ahead.
NASA Astrophysics Data System (ADS)
Ryabov, V. A.
2015-08-01
Quantum systems in a mechanical embedding, the breathing mode of a small particles, optomechanical system, etc. are far not the full list of examples in which the volume exhibits quantum behavior. Traditional consideration suggests strain in small systems as a result of a collective movement of particles, rather than the dynamics of the volume as an independent variable. The aim of this work is to show that some problem here might be essentially simplified by introducing periodic boundary conditions. At this case, the volume is considered as the independent dynamical variable driven by the internal pressure. For this purpose, the concept of quantum volume based on Schrödinger’s equation in 𝕋3 manifold is proposed. It is used to explore several 1D model systems: An ensemble of free particles under external pressure, quantum manometer and a quantum breathing mode. In particular, the influence of the pressure of free particle on quantum oscillator is determined. It is shown also that correction to the spectrum of the breathing mode due to internal degrees of freedom is determined by the off-diagonal matrix elements of the quantum stress. The new treatment not using the “force” theorem is proposed for the quantum stress tensor. In the general case of flexible quantum 3D dynamics, quantum deformations of different type might be introduced similarly to monopole mode.
A cyclic universe approach to fine tuning
NASA Astrophysics Data System (ADS)
Alexander, Stephon; Cormack, Sam; Gleiser, Marcelo
2016-06-01
We present a closed bouncing universe model where the value of coupling constants is set by the dynamics of a ghost-like dilatonic scalar field. We show that adding a periodic potential for the scalar field leads to a cyclic Friedmann universe where the values of the couplings vary randomly from one cycle to the next. While the shuffling of values for the couplings happens during the bounce, within each cycle their time-dependence remains safely within present observational bounds for physically-motivated values of the model parameters. Our model presents an alternative to solutions of the fine tuning problem based on string landscape scenarios.
Recurrence of cyclic esotropia after surgical correction.
Cahill, M; Walsh, J; McAleer, A
1999-12-01
Cyclic esotropia is a rare form of strabismus in which a convergent squint appears and disappears typically, but not always, in a regular 48-hour cycle. Characteristically, the convergent squint, when present, has a large angle with associated suppression and no binocular function. On normal or "nonsquinting" days, no manifest deviation is detectable (although in some cases there may be an esophoria). Physiologic diplopia is appreciated, whereas fusion and stereopsis are all normal. Amblyopia may occur in up to 20% of cases. PMID:10613585
Quantum games as quantum types
NASA Astrophysics Data System (ADS)
Delbecque, Yannick
In this thesis, we present a new model for higher-order quantum programming languages. The proposed model is an adaptation of the probabilistic game semantics developed by Danos and Harmer [DH02]: we expand it with quantum strategies which enable one to represent quantum states and quantum operations. Some of the basic properties of these strategies are established and then used to construct denotational semantics for three quantum programming languages. The first of these languages is a formalisation of the measurement calculus proposed by Danos et al. [DKP07]. The other two are new: they are higher-order quantum programming languages. Previous attempts to define a denotational semantics for higher-order quantum programming languages have failed. We identify some of the key reasons for this and base the design of our higher-order languages on these observations. The game semantics proposed in this thesis is the first denotational semantics for a lambda-calculus equipped with quantum types and with extra operations which allow one to program quantum algorithms. The results presented validate the two different approaches used in the design of these two new higher-order languages: a first one where quantum states are used through references and a second one where they are introduced as constants in the language. The quantum strategies presented in this thesis allow one to understand the constraints that must be imposed on quantum type systems with higher-order types. The most significant constraint is the fact that abstraction over part of the tensor product of many unknown quantum states must not be allowed. Quantum strategies are a new mathematical model which describes the interaction between classical and quantum data using system-environment dialogues. The interactions between the different parts of a quantum system are described using the rich structure generated by composition of strategies. This approach has enough generality to be put in relation with other
NASA Astrophysics Data System (ADS)
Levy, Amikam; Diósi, Lajos; Kosloff, Ronnie
2016-05-01
In this work we present the concept of a quantum flywheel coupled to a quantum heat engine. The flywheel stores useful work in its energy levels, while additional power is extracted continuously from the device. Generally, the energy exchange between a quantum engine and a quantized work repository is accompanied by heat, which degrades the charging efficiency. Specifically when the quantum harmonic oscillator acts as a work repository, quantum and thermal fluctuations dominate the dynamics. Quantum monitoring and feedback control are applied to the flywheel in order to reach steady state and regulate its operation. To maximize the charging efficiency one needs a balance between the information gained by measuring the system and the information fed back to the system. The dynamics of the flywheel are described by a stochastic master equation that accounts for the engine, the external driving, the measurement, and the feedback operations.
NASA Astrophysics Data System (ADS)
Xu, Ping
We introduce a general notion of quantum universal enveloping algebroids (QUE algebroids), or quantum groupoids, as a unification of quantum groups and star-products. Some basic properties are studied including the twist construction and the classical limits. In particular, we show that a quantum groupoid naturally gives rise to a Lie bialgebroid as a classical limit. Conversely, we formulate a conjecture on the existence of a quantization for any Lie bialgebroid, and prove this conjecture for the special case of regular triangular Lie bialgebroids. As an application of this theory, we study the dynamical quantum groupoid , which gives an interpretation of the quantum dynamical Yang-Baxter equation in terms of Hopf algebroids.
NASA Astrophysics Data System (ADS)
Braun, Daniel; Giraud, Olivier; Braun, Peter A.
2010-03-01
We introduce and study a measure of ``quantumness'' of a quantum state based on its Hilbert-Schmidt distance from the set of classical states. ``Classical states'' were defined earlier as states for which a positive P-function exists, i.e. they are mixtures of coherent states [1]. We study invariance properties of the measure, upper bounds, and its relation to entanglement measures. We evaluate the quantumness of a number of physically interesting states and show that for any physical system in thermal equilibrium there is a finite critical temperature above which quantumness vanishes. We then use the measure for identifying the ``most quantum'' states. Such states are expected to be potentially most useful for quantum information theoretical applications. We find these states explicitly for low-dimensional spin-systems, and show that they possess beautiful, highly symmetric Majorana representations. [4pt] [1] Classicality of spin states, Olivier Giraud, Petr Braun, and Daniel Braun, Phys. Rev. A 78, 042112 (2008)
NASA Astrophysics Data System (ADS)
Hsu, Tzu-Yin Jean
It is commonly accepted that fatigue crack is initiated under tensile fatigue stresses. However, practical examples demonstrate that cracks may also initiate under pure compressive fluctuating loads such as the failures observed in aircraft landing gear frames. However, the mechanism of such failures is rarely investigated. Furthermore, knowledge on cyclic deformation response under pure compressive fatigue condition is also very limited or non-existent. Our recent work already verified that fatigue cracks may nucleate from stress concentration sites under pure compression fatigue, but whether or not a form of stress concentration is always needed to initiate a crack under pure compression fatigue remains uncertain. In this study, compression fatigue tests under different peak stresses were carried out on smooth bars of fully annealed OFHC Copper. The purpose of these tests is to investigate not only the cyclic deformation response but also the possibility of crack nucleation without the stress concentrator. Results showed that overall the cyclic stress-strain response and microstructural evolution of OFHC Copper under pure compression fatigue exhibits rather dissimilar behaviour compared to those under symmetrical fatigue. The specimens hardened rapidly within 10 cycles under pure compression fatigue unlike the gradual cyclic hardening behaviour in symmetrical fatigue with the same peak stress amplitude. Compressive cyclic creep behaviour was also observed under the same testing conditions. Moreover, unlike conventional tension-compression fatigue, only moderate slip activity was detectable on the surface instead of typical PSB features detected from TEM observations. The surface observations has revealed that surface slip bands did not increase in number nor did they become more pronounced in height with increasing number of cycles. In addition, surface roughening by grain boundary extrusion was detected to become more severe as the cycling progressed. Therefore
Cyclical components of local rainfall data
NASA Astrophysics Data System (ADS)
Mentz, R. P.; D'Urso, M. A.; Jarma, N. M.; Mentz, G. B.
2000-02-01
This paper reports on the use of a comparatively simple statistical methodology to study local short time series rainfall data. The objective is to help in agricultural planning, by diminishing the risks associated with some uncertainties affecting this business activity.The analysis starts by assuming a model of unobservable components, trend, cycle, seasonal and irregular, that is well known in many areas of application. When series are in the realm of business and economics, the statistical methods popularized by the US Census Bureau US National Bureau of Economic Research are used for seasonal and cyclical estimation, respectively. The flexibility of these methods makes them good candidates to be applied in the meteorological context, and this is done in this paper for a selection of monthly rainfall time series.Use of the results to help in analysing and forecasting cyclical components is emphasized. The results are interesting. An agricultural entrepreneur, or a group of them located in a single geographical region, will profit by systematically collecting information (monthly in our work) about rainfall, and adopting the scheme of analysis described in this paper.
Rf cavity primer for cyclic proton accelerators
NASA Astrophysics Data System (ADS)
Griffin, J. E.
1988-04-01
The electrical and mechanical properities of particle accelerator rf cavities are described in a manner which will be useful to physics and engineering graduates entering the accelerator field. The discussion is limited to proton (or antiproton) synchrotron accelerators or storage rings operating roughly in the range of 20 to 200 MHz. The very high gradient, fixed frequency UHF or microwave devices appropriate for electron machines and the somewhat lower frequency and broader bandwidth devices required for heavy ion accelerators are discussed extensively in other papers in this series. While it is common practice to employ field calculation programs such as SUPERFISH, URMEL, or MAFIA as design aids in the development of rf cavities, we attempt here to elucidate various of the design parameters commonly dealt with in proton machines through the use of simple standing wave coaxial resonator expressions. In so doing, we treat only standing wave structures. Although low-impedance, moderately broad pass-band travelling wave accelerating systems are used in the CERN SPS, such systems are more commonly found in linacs, and they have not been used widely in large cyclic accelerators. Two appendices providing useful supporting material regarding relativistic particle dynamics and synchrotron motion in cyclic accelerators are added to supplement the text.
Effect of Registration on Cyclical Kinematic Data
Crane, Elizabeth A.; Cassidy, Ruth B.; Rothman, Edward D.; Gerstner, Geoffrey E.
2010-01-01
Given growing interest in Functional Data Analysis (FDA) as a useful method for analyzing human movement data, it is critical to understand the effects of standard FDA procedures, including registration, on biomechanical analyses. Registration is used to reduce phase variability between curves while preserving the individual curves shape and amplitude. The application of three methods available to assess registration could benefit those in the biomechanics community using FDA techniques: comparison of mean curves, comparison of average RMS values, and assessment of time-warping functions. Therefore, the present study has two purposes. First, the necessity of registration applied to cyclical data after time normalization is assessed. Second, we illustrate the three methods for evaluating registration effects. Masticatory jaw movements of 22 healthy adults (2 males, 21 females) were tracked while subjects chewed a gum-based pellet for 20 seconds. Motion data were captured at 60 Hz with two gen-locked video cameras. Individual chewing cycles were time normalized and then transformed into functional observations. Registration did not affect mean curves and warping functions were linear. Although registration decreased the RMS, indicating a decrease in inter-subject variability, the difference was not statistically significant. Together these results indicate that registration may not always be necessary for cyclical chewing data. An important contribution of this paper is the illustration of three methods for evaluating registration that are easy to apply and useful for judging whether the extra data manipulation is necessary. PMID:20537335
Superplastic deformation induced by cyclic hydrogen charging
Choe, Heeman; Schuh, Christopher A.; Dunand, David C.
2008-05-15
Deformation under the combined action of external stress and cyclic hydrogen charging/discharging is studied in a model material, titanium. Cyclic charging with hydrogen is carried out at 860 deg. C, which repeatedly triggers the transformation between hydrogen-lean {alpha}-Ti and hydrogen-rich {beta}-Ti. Due to bias from the externally applied tensile stress, the internal mismatch strains produced by this isothermal {alpha}-{beta} transformation accumulate preferentially along the loading axis. These strain increments are linearly proportional to the applied stress, i.e., flow is ideally Newtonian, at small stress levels (below {approx}2 MPa). Therefore, after multiple chemical cycles, a tensile engineering strain of 100% is achieved without fracture, with an average strain rate of 10{sup -5} s{sup -1}, which demonstrates for the first time that superplastic elongations can be achieved by chemical cycling. The effect of hydrogen partial pressure, cycle time, and external stress on the value of the superplastic strain increments is experimentally measured and discussed in light of a diffusional phase transformation model. Special attention is paid to understanding the two contributions to the internal mismatch strains from the phase transformation and lattice swelling.
Strain gradient effects on cyclic plasticity
NASA Astrophysics Data System (ADS)
Niordson, Christian F.; Legarth, Brian Nyvang
2010-04-01
Size effects on the cyclic shear response are studied numerically using a recent higher order strain gradient visco-plasticity theory accounting for both dissipative and energetic gradient hardening. Numerical investigations of the response under cyclic pure shear and shear of a finite slab between rigid platens have been carried out, using the finite element method. It is shown for elastic-perfectly plastic solids how dissipative gradient effects lead to increased yield strength, whereas energetic gradient contributions lead to increased hardening as well as a Bauschinger effect. For linearly hardening materials it is quantified how dissipative and energetic gradient effects promote hardening above that of conventional predictions. Usually, increased hardening is attributed to energetic gradient effects, but here it is found that also dissipative gradient effects lead to additional hardening in the presence of conventional material hardening. Furthermore, it is shown that dissipative gradient effects can lead to both an increase and a decrease in the dissipation per load cycle depending on the magnitude of the dissipative length parameter, whereas energetic gradient effects lead to decreasing dissipation for increasing energetic length parameter. For dissipative gradient effects it is found that dissipation has a maximum value for some none zero value of the material length parameter, which depends on the magnitude of the deformation cycles.
Abstract Algebra, Projective Geometry and Time Encoding of Quantum Information
NASA Astrophysics Data System (ADS)
Planat, Michel; Saniga, Metod
2005-10-01
Algebraic geometrical concepts are playing an increasing role in quantum applications such as coding, cryptography, tomography and computing. We point out here the prominent role played by Galois fields viewed as cyclotomic extensions of the integers modulo a prime characteristic p. They can be used to generate efficient cyclic encoding, for transmitting secrete quantum keys, for quantum state recovery and for error correction in quantum computing. Finite projective planes and their generalization are the geometric counterpart to cyclotomic concepts, their coordinatization involves Galois fields, and they have been used repetitively for enciphering and coding. Finally, the characters over Galois fields are fundamental for generating complete sets of mutually unbiased bases, a generic concept of quantum information processing and quantum entanglement. Gauss sums over Galois fields ensure minimum uncertainty under such protocols. Some Galois rings which are cyclotomic extensions of the integers modulo 4 are also becoming fashionable for their role in time encoding and mutual unbiasedness.
Coleman, Piers; Schofield, Andrew J
2005-01-20
As we mark the centenary of Albert Einstein's seminal contribution to both quantum mechanics and special relativity, we approach another anniversary--that of Einstein's foundation of the quantum theory of solids. But 100 years on, the same experimental measurement that puzzled Einstein and his contemporaries is forcing us to question our understanding of how quantum matter transforms at ultra-low temperatures. PMID:15662409
Energy Storage of Linear and Cyclic Electron Flows in Photosynthesis 1
Cha, Yuan; Mauzerall, David C.
1992-01-01
The energy storage of photosynthesis in the green alga Chlorella vulgaris was determined by pulsed, time-resolved photoacoustics. The energy storage of the linear electron transfer process in photosynthesis, of cyclic photosystem (PS) I, and possibly of PSII was determined by selection of excitation wavelength and of flash interval. At 695 nm excitation, a rather large cyclic PSI energy storage of 0.68 ± 0.04 eV/quantum of energy at 8 ms after a 1-μs flash was obtained. This energy remained the same at flash intervals of 0.35 to 60 s and was independent of the presence of 3-(3,4-dichlorophenyl)-1,1-dimethylurea. We tentatively assign this energy to the ferredoxin-NADP-reductase-ferredoxin and oxidized cytochrome b6/f complexes. An efficient distribution of energy between cyclic and linear systems is obtained with the simple assumption that the turnover time of the cyclic system is slower than that of the linear system. The energy storage of linear electron flow was determined by 655 nm excitation of Chlorella with a short flash interval of 0.35 s per flash. It was calculated to be 0.50 ± 0.03 eV/hv, close to that expected for oxygen and NADPH formation. The energy storage of PSII is determined by excitation of Chlorella at 655 nm with a long flash interval of 60 s per flash. It was calculated to be 1.07 ± 0.05 eV/hv, consistent with the energy storage being in S-states and the secondary electron acceptor of PSII with a calculated redox energy of 1.03 eV/hv. In the presence of 1 μm 3-(3,4-dichlorophenyl)-1,1-dimethylurea, the calculated energy storage in PSII is still significant, 0.53 ± 0.04 eV/hv. This probably indicates a significant cyclic electron flow around PSII. These cyclic flows may contribute considerably to energy storage in photosynthesis. PMID:16653211
Interpretation of tandem mass spectra obtained from cyclic nonribosomal peptides.
Liu, Wei-Ting; Ng, Julio; Meluzzi, Dario; Bandeira, Nuno; Gutierrez, Marcelino; Simmons, Thomas L; Schultz, Andrew W; Linington, Roger G; Moore, Bradley S; Gerwick, William H; Pevzner, Pavel A; Dorrestein, Pieter C
2009-06-01
Natural and non-natural cyclic peptides are a crucial component in drug discovery programs because of their considerable pharmaceutical properties. Cyclosporin, microcystins, and nodularins are all notable pharmacologically important cyclic peptides. Because these biologically active peptides are often biosynthesized nonribosomally, they often contain nonstandard amino acids, thus increasing the complexity of the resulting tandem mass spectrometry data. In addition, because of the cyclic nature, the fragmentation patterns of many of these peptides showed much higher complexity when compared to related counterparts. Therefore, at the present time it is still difficult to annotate cyclic peptides MS/MS spectra. In this current work, an annotation program was developed for the annotation and characterization of tandem mass spectra obtained from cyclic peptides. This program, which we call MS-CPA is available as a web tool (http://lol.ucsd.edu/ms-cpa_v1/Input.py). Using this program, we have successfully annotated the sequence of representative cyclic peptides, such as seglitide, tyrothricin, desmethoxymajusculamide C, dudawalamide A, and cyclomarins, in a rapid manner and also were able to provide the first-pass structure evidence of a newly discovered natural product based on predicted sequence. This compound is not available in sufficient quantities for structural elucidation by other means such as NMR. In addition to the development of this cyclic annotation program, it was observed that some cyclic peptides fragmented in unexpected ways resulting in the scrambling of sequences. In summary, MS-CPA not only provides a platform for rapid confirmation and annotation of tandem mass spectrometry data obtained with cyclic peptides but also enables quantitative analysis of the ion intensities. This program facilitates cyclic peptide analysis, sequencing, and also acts as a useful tool to investigate the uncommon fragmentation phenomena of cyclic peptides and aids the
Synthesis of cyclic oligonucleotides by a modified phosphotriester approach.
de Vroom, E; Broxterman, H J; Sliedregt, L A; van der Marel, G A; van Boom, J H
1988-01-01
Evidence will be presented to show that the allyl group is suitable for the protection of a 3'-terminal phosphodiester function. The latter will be demonstrated by the synthesis, via a phosphotriester approach, of two cyclic tetraribonucleotides [r(AAAA) and r(UAMe2UAMe2)], two cyclic hexadeoxyribonucleotides [d(CGCGCG) and d(TAAAAA)] and a cyclic octadeoxyribonucleotide [d(CGTGCGTG)]. PMID:3380690
NASA Astrophysics Data System (ADS)
Tartakovskii, Alexander
2012-07-01
Part I. Nanostructure Design and Structural Properties of Epitaxially Grown Quantum Dots and Nanowires: 1. Growth of III/V semiconductor quantum dots C. Schneider, S. Hofling and A. Forchel; 2. Single semiconductor quantum dots in nanowires: growth, optics, and devices M. E. Reimer, N. Akopian, M. Barkelid, G. Bulgarini, R. Heeres, M. Hocevar, B. J. Witek, E. Bakkers and V. Zwiller; 3. Atomic scale analysis of self-assembled quantum dots by cross-sectional scanning tunneling microscopy and atom probe tomography J. G. Keizer and P. M. Koenraad; Part II. Manipulation of Individual Quantum States in Quantum Dots Using Optical Techniques: 4. Studies of the hole spin in self-assembled quantum dots using optical techniques B. D. Gerardot and R. J. Warburton; 5. Resonance fluorescence from a single quantum dot A. N. Vamivakas, C. Matthiesen, Y. Zhao, C.-Y. Lu and M. Atature; 6. Coherent control of quantum dot excitons using ultra-fast optical techniques A. J. Ramsay and A. M. Fox; 7. Optical probing of holes in quantum dot molecules: structure, symmetry, and spin M. F. Doty and J. I. Climente; Part III. Optical Properties of Quantum Dots in Photonic Cavities and Plasmon-Coupled Dots: 8. Deterministic light-matter coupling using single quantum dots P. Senellart; 9. Quantum dots in photonic crystal cavities A. Faraon, D. Englund, I. Fushman, A. Majumdar and J. Vukovic; 10. Photon statistics in quantum dot micropillar emission M. Asmann and M. Bayer; 11. Nanoplasmonics with colloidal quantum dots V. Temnov and U. Woggon; Part IV. Quantum Dot Nano-Laboratory: Magnetic Ions and Nuclear Spins in a Dot: 12. Dynamics and optical control of an individual Mn spin in a quantum dot L. Besombes, C. Le Gall, H. Boukari and H. Mariette; 13. Optical spectroscopy of InAs/GaAs quantum dots doped with a single Mn atom O. Krebs and A. Lemaitre; 14. Nuclear spin effects in quantum dot optics B. Urbaszek, B. Eble, T. Amand and X. Marie; Part V. Electron Transport in Quantum Dots Fabricated by
May Cyclic Nucleotides Be a Source for Abiotic RNA Synthesis?
NASA Astrophysics Data System (ADS)
Costanzo, Giovanna; Pino, Samanta; Botta, Giorgia; Saladino, Raffaele; di Mauro, Ernesto
2011-12-01
Nucleic bases are obtained by heating formamide in the presence of various catalysts. Formamide chemistry also allows the formation of acyclonucleosides and the phosphorylation of nucleosides in every possible position, also affording 2',3' and 3',5' cyclic forms. We have reported that 3',5' cyclic GMP and 3',5' cyclic AMP polymerize in abiotic conditions yielding short oligonucleotides. The characterization of this reaction is being pursued, several of its parameters have been determined and experimental caveats are reported. The yield of non-enzymatic polymerization of cyclic purine nucleotides is very low. Polymerization is strongly enhanced by the presence of base-complementary RNA sequences.
Dissipative quantum computing with open quantum walks
Sinayskiy, Ilya; Petruccione, Francesco
2014-12-04
An open quantum walk approach to the implementation of a dissipative quantum computing scheme is presented. The formalism is demonstrated for the example of an open quantum walk implementation of a 3 qubit quantum circuit consisting of 10 gates.
Quantum computer games: quantum minesweeper
NASA Astrophysics Data System (ADS)
Gordon, Michal; Gordon, Goren
2010-07-01
The computer game of quantum minesweeper is introduced as a quantum extension of the well-known classical minesweeper. Its main objective is to teach the unique concepts of quantum mechanics in a fun way. Quantum minesweeper demonstrates the effects of superposition, entanglement and their non-local characteristics. While in the classical minesweeper the goal of the game is to discover all the mines laid out on a board without triggering them, in the quantum version there are several classical boards in superposition. The goal is to know the exact quantum state, i.e. the precise layout of all the mines in all the superposed classical boards. The player can perform three types of measurement: a classical measurement that probabilistically collapses the superposition; a quantum interaction-free measurement that can detect a mine without triggering it; and an entanglement measurement that provides non-local information. The application of the concepts taught by quantum minesweeper to one-way quantum computing are also presented.
Quantum Cryptography Without Quantum Uncertainties
NASA Astrophysics Data System (ADS)
Durt, Thomas
2002-06-01
Quantum cryptography aims at transmitting a random key in such a way that the presence of a spy eavesdropping the communication would be revealed by disturbances in the transmission of the message. In standard quantum cryptography, this unavoidable disturbance is a consequence of the uncertainty principle of Heisenberg. We propose in this paper to replace quantum uncertainties by generalised, technological uncertainties, and discuss the realisability of such an idea. The proposed protocol can be considered as a simplification, but also as a generalisation of the standard quantum cryptographic protocols.
NASA Technical Reports Server (NTRS)
Lee, H.; Kok, P.; Dowling, J. P.
2002-01-01
This paper addresses the formal equivalence between the Mach-Zehnder interferometer, the Ramsey spectroscope, and a specific quantum logical gate. Based on this equivalence we introduce the quantum Rosetta Stone, and we describe a projective measurement scheme for generating the desired correlations between the interferometric input states in order to achieve Heisenberg-limited sensitivity.
Trevors, J T; Masson, L
2011-01-01
During his famous 1943 lecture series at Trinity College Dublin, the reknown physicist Erwin Schrodinger discussed the failure and challenges of interpreting life by classical physics alone and that a new approach, rooted in Quantum principles, must be involved. Quantum events are simply a level of organization below the molecular level. This includes the atomic and subatomic makeup of matter in microbial metabolism and structures, as well as the organic, genetic information code of DNA and RNA. Quantum events at this time do not elucidate, for example, how specific genetic instructions were first encoded in an organic genetic code in microbial cells capable of growth and division, and its subsequent evolution over 3.6 to 4 billion years. However, due to recent technological advances, biologists and physicists are starting to demonstrate linkages between various quantum principles like quantum tunneling, entanglement and coherence in biological processes illustrating that nature has exerted some level quantum control to optimize various processes in living organisms. In this article we explore the role of quantum events in microbial processes and endeavor to show that after nearly 67 years, Schrödinger was prophetic and visionary in his view of quantum theory and its connection with some of the fundamental mechanisms of life. PMID:21368338
NASA Astrophysics Data System (ADS)
Hsu, Tzu-Yin Jean
It is commonly accepted that fatigue crack is initiated under tensile fatigue stresses. However, practical examples demonstrate that cracks may initiate under pure compressive fluctuating loads, e.g. the failures observed in aircraft landing gear frames. As the mechanism of such failures is rarely investigated, there is very limited or non-existent knowledge pool on cyclic deformation response under pure compressive fatigue condition. Our recent work verified that fatigue cracks may nucleate from stress concentration sites under pure compression fatigue, but whether or not a form of stress concentration is always needed to initiate a crack remains uncertain. In this study, compression fatigue tests under different peak stresses were carried out on smooth bars of fully annealed OFHC Copper. The purpose of these tests is to investigate not only the cyclic deformation response but also the possibility of crack nucleation without the stress concentrator. Results showed that overall the cyclic stress-strain response and microstructural evolution of OFHC Copper under pure compression fatigue exhibits rather dissimilar behaviour compared to those under symmetrical fatigue. The specimens hardened rapidly within 10 cycles under pure compression fatigue unlike the gradual cyclic hardening behaviour in symmetrical fatigue with the same peak stress amplitude. Compressive cyclic creep behaviour was also observed. Moreover, TEM observation showed that only moderate slip activity was detectable on the surface instead of typical PSB features. The surface observations revealed that surface slip bands did not increase in number nor height as cycling progressed. In addition, surface roughening by grain boundary extrusion was detected to become more severe with further cycling. Therefore, the plastic strain accommodated within the samples was not mainly related to dislocation activities. Instead, the mechanism of cyclic creep response for pure compression fatigue was correlated and
Cyclic Vomiting Presentations Following Marijuana Liberalization in Colorado
Kim, Howard S.; Anderson, John D.; Saghafi, Omeed; Heard, Kennon J.; Monte, Andrew A.
2015-01-01
Objectives Case reports have described a syndrome of cyclic vomiting associated with chronic marijuana use, termed cannabinoid hyperemesis syndrome. The primary objective was to determine the prevalence of patients presenting with cyclic vomiting before and after the liberalization of medical marijuana in Colorado in 2009. The secondary objective was to describe the odds of marijuana use among cyclic vomiting visits in these same time periods. Methods This was a cross-sectional study of cyclic vomiting visits to the emergency department (ED) before and after marijuana liberalization. ED visits with International Classification of Diseases, ninth revision, coding for cyclic vomiting or that met diagnostic criteria for cyclic vomiting by the Rome III criteria were included. Results The authors reviewed 2,574 visits and identified 36 patients diagnosed with cyclic vomiting over 128 visits. The prevalence of cyclic vomiting visits increased from 41 per 113,262 ED visits to 87 per 125,095 ED visits after marijuana liberalization, corresponding to a prevalence ratio of 1.92 (95% confidence interval [CI] = 1.33 to 2.79). Patients with cyclic vomiting in the postliberalization period were more likely to have marijuana use documented than patients in the preliberalization period (odds ratio = 3.59, 95% CI = 1.44 to 9.00). Conclusions The prevalence of cyclic vomiting presentations nearly doubled after the liberalization of medical marijuana. Patients presenting with cyclic vomiting in the postliberalization period were more likely to endorse marijuana use, although it is unclear whether this was secondary to increased marijuana use, more accurate marijuana reporting, or both. PMID:25903855
NASA Astrophysics Data System (ADS)
Coecke, Bob
2010-01-01
Why did it take us 50 years since the birth of the quantum mechanical formalism to discover that unknown quantum states cannot be cloned? Yet, the proof of the 'no-cloning theorem' is easy, and its consequences and potential for applications are immense. Similarly, why did it take us 60 years to discover the conceptually intriguing and easily derivable physical phenomenon of 'quantum teleportation'? We claim that the quantum mechanical formalism doesn't support our intuition, nor does it elucidate the key concepts that govern the behaviour of the entities that are subject to the laws of quantum physics. The arrays of complex numbers are kin to the arrays of 0s and 1s of the early days of computer programming practice. Using a technical term from computer science, the quantum mechanical formalism is 'low-level'. In this review we present steps towards a diagrammatic 'high-level' alternative for the Hilbert space formalism, one which appeals to our intuition. The diagrammatic language as it currently stands allows for intuitive reasoning about interacting quantum systems, and trivialises many otherwise involved and tedious computations. It clearly exposes limitations such as the no-cloning theorem, and phenomena such as quantum teleportation. As a logic, it supports 'automation': it enables a (classical) computer to reason about interacting quantum systems, prove theorems, and design protocols. It allows for a wider variety of underlying theories, and can be easily modified, having the potential to provide the required step-stone towards a deeper conceptual understanding of quantum theory, as well as its unification with other physical theories. Specific applications discussed here are purely diagrammatic proofs of several quantum computational schemes, as well as an analysis of the structural origin of quantum non-locality. The underlying mathematical foundation of this high-level diagrammatic formalism relies on so-called monoidal categories, a product of a fairly
Synthesis of N-substituted Cyclic Hydrocarbons, such as Pyrimidine, in The Ionosphere of Titan
NASA Astrophysics Data System (ADS)
Bera, P. P.; Peverati, R.; Head-Gordon, M.; Lee, T. J.
2014-12-01
The instruments on board the CASSINI spacecraft observed large carbonaceous molecules in the upper atmosphere of Titan. How these large polyatomic molecules are synthesized in such exotic conditions is, thus far, unknown. Molecular ions, including positive and negative ions, are in relative abundance in the ionosphere of Titan. Hence, barrierless ion-molecule interactions may play a major role in guiding molecules towards each other and initiating reactions. We study these condensation pathways to determine whether they are a viable means of forming large pure hydrocarbon molecules, and nitrogen-containing carbonaceous chains, stacks, and even cyclic compounds. By employing accurate quantum chemical methods we have investigated the processes of growth, structures, nature of bonding, mechanisms, and spectroscopic properties of the ensuing ionic products after pairing small carbon, hydrogen, and nitrogen-containing molecules with major ions observed in the upper atmosphere of Titan, e.g. C2H5+ and HCNH+. We have also studied the ion-neutral association pathways involving pure-carbon molecules e.g. acetylene, ethylene and other hydrocarbons, and their dissociation fragments in a plasma discharge. We have investigated how nitrogen atoms are incorporated into the carbon ring during growth. Specifically, we explored the mechanisms by which the synthesis of pyrimidine will be feasible in the atmosphere of Titan in conjunction with ion-mobility experiments. We have used accurate ab initio coupled cluster theory, Møller-Plesset perturbation theory, density functional theory, and coupled cluster theory quantum chemical methods together with large correlation consistent basis sets in these investigations. We found that a series of hydrocarbons with a specific stoichiometric composition prefers cyclic molecule formation rather than chains. Some of the association products we investigated have large oscillator strengths for charge-transfer type electronic excitations in the
Stability of fuses under cyclic load
NASA Astrophysics Data System (ADS)
Namitokov, K. K.; Shklovskiy, I. G.
1984-05-01
Thermal stresses in fuses, stimulated by the high degree of mechanical stiffness and the cause of low stability under cyclic current loads, can be reduced by reducing the stiffness of the fuse element, which is typically a strap welded to contact caps at both ends. It is indicated that the stiffness can be reduced by increasing the length and decreasing the cross section. A thin strap consists of flat and bend segments. Simple bending and multiple bending were evaluated. It is indicated that bent fuse segments are less stiff than straight segments, that the relation between stiffness and amplitude of the bend is an inverse power law with the amplitude to a power much higher than squared, that the decrease of overall stiffness is approximately proportional to the number of bends, and that rectangular or circular bending reduce the stiffness most efficiently, inasmuch as such contours envelop the largest areas on the basis of fixed length.
COSP - A computer model of cyclic oxidation
NASA Technical Reports Server (NTRS)
Lowell, Carl E.; Barrett, Charles A.; Palmer, Raymond W.; Auping, Judith V.; Probst, Hubert B.
1991-01-01
A computer model useful in predicting the cyclic oxidation behavior of alloys is presented. The model considers the oxygen uptake due to scale formation during the heating cycle and the loss of oxide due to spalling during the cooling cycle. The balance between scale formation and scale loss is modeled and used to predict weight change and metal loss kinetics. A simple uniform spalling model is compared to a more complex random spall site model. In nearly all cases, the simpler uniform spall model gave predictions as accurate as the more complex model. The model has been applied to several nickel-base alloys which, depending upon composition, form Al2O3 or Cr2O3 during oxidation. The model has been validated by several experimental approaches. Versions of the model that run on a personal computer are available.
Statistical cyclicity of the supercontinent cycle
NASA Astrophysics Data System (ADS)
Rolf, T.; Coltice, N.; Tackley, P. J.
2014-04-01
Supercontinents like Pangea impose a first-order control on Earth's evolution as they modulate global heat loss, sea level, climate, and biodiversity. In a traditional view, supercontinents form and break up in a regular, perhaps periodic, manner in a cycle lasting several 100 Myr as reflected in the assembly times of Earth's major continental aggregations: Columbia, Rodinia, and Pangea. However, modern views of the supercontinent cycle propose a more irregular evolution on the basis of an improved understanding of the Precambrian geologic record. Here we use fully dynamic spherical mantle convection models featuring plate-like behavior and continental drift to investigate supercontinent formation and breakup. We further dismiss the concept of regularity but suggest a statistical cyclicity in which the supercontinent cycle may have a characteristic period imposed by mantle and lithosphere properties, but this is hidden in immense fluctuations between different cycles that arise from the chaotic nature of mantle flow.
Monitoring thermoplastic composites under cyclic bending tests
NASA Astrophysics Data System (ADS)
Boccardi, Simone; Meola, Carosena; Carlomagno, Giovanni Maria; Simeoli, Giorgio; Acierno, Domenico; Russo, Pietro
2016-05-01
This work is concerned with the use of infrared thermography to visualize temperature variations linked to thermo-elastic effects developing over the surface of a specimen undergoing deflection under bending tests. Several specimens are herein considered, which involve change of matrix and/or reinforcement. More specifically, the matrix is either a pure polypropylene, or a polypropylene added with a certain percentage of compatibilizing agent; the reinforcement is made of glass, or jute. Cyclic bending tests are carried out by the aid of an electromechanical actuator. Each specimen is viewed, during deflection, from one surface by an infrared imaging device. As main finding the different specimens display surface temperature variations which depend on the type of material in terms of both matrix and reinforcement.
Cyclic steps incised on experimental bedrock
NASA Astrophysics Data System (ADS)
Yokokawa, M.; Kyogoku, A.; Kotera, A.; Izumi, N.
2013-12-01
In rivers flowing in mountain areas, a series of steps are often observed on bedrock. They are thought to be cyclic steps formed due to erosion of bedrock, which should be driven by abrasion due to bedload sediment transport. We demonstrated a series of flume experiments of the formation of cyclic steps on bedrock by abrasion due to bedload transportation using weak mortar as the model bedrock. We also compared the shapes of the steps reproduced in the experiments with those obtained in the analysis. The experiments were conducted using a 1.5 m long, 2 cm wide, and 20 cm deep flume made of glass in Osaka Institute of Technology. The flume has 10-cm-high weirs at both ends, so that there is a 10-cm-deep reservoir. We put mortar into the reservoir and hardened it. In order to make a highly erodible mortar, we casted the mortar with extremely low amount of cement. The ratio of cement, sand (0.2 mm in diameter), and water is x:150:50 (x ranges 1-3). The flume is tilted by 10 degrees. The water and colored sand is supplied from a head tank to the upstream end of the flume, flows on 'model bedrock' in the flume, and was dropped from the downstream end. We observed morphological changes of the surface of the bedrock by photos. We also used a laser displacement sensor to measure the surface topography of the 'model bedrock' before and after each run. The configuration of steps largely depends on the hardness of model bedrocks. In the case of the softest model bedrock (cement-sand-water ratio is 1:150:50) with small amount of sand, long-drawn potholes tend to be formed. Clear cyclic steps are formed on harder model bedrocks with large cement-sand-water ratios such as 2:150:50 and 3:150:50. When a series of steps are formed on the bed, typical wavelength and wave height are approximately 20 cm, and 2 - 3 cm, respectively. The general shape of a step is characterized by a relatively long downward-inclined slope just upstream of a short upward-inclined slope. The feature of
Globally synchronized oscillations in complex cyclic games
NASA Astrophysics Data System (ADS)
Rulquin, Charlotte; Arenzon, Jeferson J.
2014-03-01
The rock-paper-scissors game and its generalizations with S >3 species are well-studied models for cyclically interacting populations. Four is, however, the minimum number of species that, by allowing other interactions beyond the single, cyclic loop, breaks both the full intransitivity of the food graph and the one-predator, one-prey symmetry. Lütz et al. [J. Theor. Biol. 317, 286 (2013), 10.1016/j.jtbi.2012.10.024] have shown the existence, on a square lattice, of two distinct phases, with either four or three coexisting species. In both phases, each agent is eventually replaced by one of its predators, but these strategy oscillations remain localized as long as the interactions are short ranged. Distant regions may be either out of phase or cycling through different food-web subloops (if any). Here we show that upon replacing a minimum fraction Q of the short-range interactions by long-range ones, there is a Hopf bifurcation, and global oscillations become stable. Surprisingly, to build such long-distance, global synchronization, the four-species coexistence phase requires fewer long-range interactions than the three-species phase, while one would naively expect the opposite to be true. Moreover, deviations from highly homogeneous conditions (χ =0 or 1) increase Qc, and the more heterogeneous is the food web, the harder the synchronization is. By further increasing Q, while the three-species phase remains stable, the four-species one has a transition to an absorbing, single-species state. The existence of a phase with global oscillations for S >3, when the interaction graph has multiple subloops and several possible local cycles, leads to the conjecture that global oscillations are a general characteristic, even for large, realistic food webs.
Presence of quantum correlations results in a nonvanishing ergotropic gap
NASA Astrophysics Data System (ADS)
Mukherjee, Amit; Roy, Arup; Bhattacharya, Some Sankar; Banik, Manik
2016-05-01
The paradigm of extracting work from an isolated quantum system through a cyclic Hamiltonian process is a topic of immense research interest. The optimal work extracted under such a process is termed ergotropy [Europhys. Lett. 67, 565 (2004)]. Here, in a multiparty scenario, we consider only a class of such cyclic processes that can be implemented locally, giving rise to the concept of local ergotropy. Eventually, the presence of quantum correlations results in a nonvanishing thermodynamic quantity called an ergotropic gap, measured by the difference between global and local ergotropy. However, the converse does not hold in general, i.e., its nonzero value does not necessarily imply the presence of quantum correlations. For arbitrary multiparty states, we quantify this gap. We also evaluate the difference between maximum global and local extractable work for arbitrary states when the system is no longer isolated but put in contact with a bath of the same local temperature.
Farrokhpour, H; Karachi, S; Chermahini, A Najafi
2016-09-01
In the present work, the chirality recognition of the enantiomers of a chiral molecule (1-phenyl-1-propanol) interacting with a nanotubular cyclic peptide (E-type cyclic decapeptide) was investigated by their ionization in the gas phase, theoretically. The absolute energy difference between the interaction of the S- and R-enantiomer with the cyclic peptide, calculated at the M06-2X/6-311++G(d, p) level of theory, was 4.70 kcal·mol(-1). Two different schemes of "Our own N-layered Integrated molecular Orbital and molecular Mechanics (ONIOM)" method such as (quantum mechanics (QM):molecular mechanics (MM)) and (QM:QM) were employed to study the effect of the interaction on the gas-phase ionization energies of the enantiomers and cyclic peptide, separately. The symmetry-adapted cluster/configuration interaction (SAC-CI) methodology was used for the calculation of the ionization energies. It was found that the difference between the interactions of R- and S-enantiomer with the cyclic peptide caused different changes in the photoelectron spectrum of each enantiomer so that these changes could be used for the chirality discrimination of the enantiomers in the gas phase. Similarly, the photoelectron spectrum of the cyclic peptide interacting with the R and S-enantiomer were calculated, separately, and it was observed that the difference in the interaction with the R- and S-enantiomer created different changes in the spectrum of cyclic peptide. Finally, it was shown that the difference in the interaction of cyclic peptide with the enantiomers of a chiral molecule in the gas phase can be used for the identification of enantiomers in the gas phase by the direct ionization. PMID:27500312
NASA Astrophysics Data System (ADS)
Casati, Giulio; Chirikov, Boris
2006-11-01
Preface; Acknowledgments; Introduction: 1. The legacy of chaos in quantum mechanics G. Casati and B. V. Chirikov; Part I. Classical Chaos and Quantum Localization: 2. Stochastic behaviour of a quantum pendulum under a periodic perturbation G. Casati, B. V. Chirikov, F. M. Izrailev and J. Ford; 3. Quantum dynamics of a nonintegrable system D. R. Grempel, R. E. Prange and S. E. Fishman; 4. Excitation of molecular rotation by periodic microwave pulses. A testing ground for Anderson localization R. Blümel, S. Fishman and U. Smilansky; 5. Localization of diffusive excitation in multi-level systems D. K. Shepelyansky; 6. Classical and quantum chaos for a kicked top F. Haake, M. Kus and R. Scharf; 7. Self-similarity in quantum dynamics L. E. Reichl and L. Haoming; 8. Time irreversibility of classically chaotic quantum dynamics K. Ikeda; 9. Effect of noise on time-dependent quantum chaos E. Ott, T. M. Antonsen Jr and J. D. Hanson; 10. Dynamical localization, dissipation and noise R. F. Graham; 11. Maximum entropy models and quantum transmission in disordered systems J.-L. Pichard and M. Sanquer; 12. Solid state 'atoms' in intense oscillating fields M. S. Sherwin; Part II. Atoms in Strong Fields: 13. Localization of classically chaotic diffusion for hydrogen atoms in microwave fields J. E. Bayfield, G. Casati, I. Guarneri and D. W. Sokol; 14. Inhibition of quantum transport due to 'scars' of unstable periodic orbits R. V. Jensen, M. M. Sanders, M. Saraceno and B. Sundaram; 15. Rubidium Rydberg atoms in strong fields G. Benson, G. Raithel and H. Walther; 16. Diamagnetic Rydberg atom: confrontation of calculated and observed spectra C.-H. Iu, G. R. Welch, M. M. Kash, D. Kleppner, D. Delande and J. C. Gay; 17. Semiclassical approximation for the quantum states of a hydrogen atom in a magnetic field near the ionization limit M. Y. Kuchiev and O. P. Sushkov; 18. The semiclassical helium atom D. Wintgen, K. Richter and G. Tanner; 19. Stretched helium: a model for quantum chaos
NASA Astrophysics Data System (ADS)
Casati, Giulio; Chirikov, Boris
1995-04-01
Preface; Acknowledgments; Introduction: 1. The legacy of chaos in quantum mechanics G. Casati and B. V. Chirikov; Part I. Classical Chaos and Quantum Localization: 2. Stochastic behaviour of a quantum pendulum under a periodic perturbation G. Casati, B. V. Chirikov, F. M. Izrailev and J. Ford; 3. Quantum dynamics of a nonintegrable system D. R. Grempel, R. E. Prange and S. E. Fishman; 4. Excitation of molecular rotation by periodic microwave pulses. A testing ground for Anderson localization R. Blümel, S. Fishman and U. Smilansky; 5. Localization of diffusive excitation in multi-level systems D. K. Shepelyansky; 6. Classical and quantum chaos for a kicked top F. Haake, M. Kus and R. Scharf; 7. Self-similarity in quantum dynamics L. E. Reichl and L. Haoming; 8. Time irreversibility of classically chaotic quantum dynamics K. Ikeda; 9. Effect of noise on time-dependent quantum chaos E. Ott, T. M. Antonsen Jr and J. D. Hanson; 10. Dynamical localization, dissipation and noise R. F. Graham; 11. Maximum entropy models and quantum transmission in disordered systems J.-L. Pichard and M. Sanquer; 12. Solid state 'atoms' in intense oscillating fields M. S. Sherwin; Part II. Atoms in Strong Fields: 13. Localization of classically chaotic diffusion for hydrogen atoms in microwave fields J. E. Bayfield, G. Casati, I. Guarneri and D. W. Sokol; 14. Inhibition of quantum transport due to 'scars' of unstable periodic orbits R. V. Jensen, M. M. Sanders, M. Saraceno and B. Sundaram; 15. Rubidium Rydberg atoms in strong fields G. Benson, G. Raithel and H. Walther; 16. Diamagnetic Rydberg atom: confrontation of calculated and observed spectra C.-H. Iu, G. R. Welch, M. M. Kash, D. Kleppner, D. Delande and J. C. Gay; 17. Semiclassical approximation for the quantum states of a hydrogen atom in a magnetic field near the ionization limit M. Y. Kuchiev and O. P. Sushkov; 18. The semiclassical helium atom D. Wintgen, K. Richter and G. Tanner; 19. Stretched helium: a model for quantum chaos
High-Temperature Cyclic Oxidation Data, Volume 1
NASA Technical Reports Server (NTRS)
Barrett, C. A.; Garlick, R. G.; Lowell, C. E.
1984-01-01
This first in a series of cyclic oxidation handbooks contains specific-weight-change-versus-time data and X-ray diffraction results derived from high-temperature cyclic tests on high-temperature, high-strength nickel-base gamma/gamma' and cobalt-base turbine alloys. Each page of data summarizes a complete test on a given alloy sample.
Advanced Developments in Cyclic Polymers: Synthesis, Applications, and Perspectives
Zhu, Yinghuai; Hosmane, Narayan S
2015-01-01
Due to the topological effect, cyclic polymers demonstrate different and unique physical and biological properties in comparison with linear counterparts having the same molecular-weight range. With advanced synthetic and analytic technologies, cyclic polymers with different topologies, e.g. multicyclic polymers, have been reported and well characterized. For example, various cyclic DNA and related structures, such as cyclic duplexes, have been prepared conveniently by click chemistry. These types of DNA have increased resistance to enzymatic degradation and have high thermodynamic stability, and thus, have potential therapeutic applications. In addition, cyclic polymers have also been used to prepare organic–inorganic hybrids for applications in catalysis, e.g. catalyst supports. Due to developments in synthetic technology, highly pure cyclic polymers could now be produced in large scale. Therefore, we anticipate discovering more applications in the near future. Despite their promise, cyclic polymers are still less explored than linear polymers like polyolefins and polycarbonates, which are widely used in daily life. Some critical issues, including controlling the molecular weight and finding suitable applications, remain big challenges in the cyclic-polymer field. This review briefly summarizes the commonly used synthetic methodologies and focuses more on the attractive functional materials and their biological properties and potential applications. PMID:26478835
MICROWAVE-ASSISTED PREPARATION OF CYCLIC UREAS FROM DIAMINES
Rajender S. Varma* and Yong-Jin Kim
Cyclic ureas are useful intermediates for a variety of pharmaceuticals and pesticides. One of the attractive approaches for the synthesis of cyclic ureas uses condensation of diamines with urea as a carbonyl source under dynamic evacuation. ...
Dietary cyclic dipeptides, apoptosis and psychiatric disorders: a hypothesis.
Semon, Bruce A
2014-06-01
Cyclic dipeptides from food and intestinal yeast cyclic dipeptides may play a role in causing psychiatric disorders such as schizophrenia. From cancer research, cyclic dipeptides such as cyclo (proline-phenylalanine) have been found to activate the pathways of apoptosis and to cause programmed cell death. Activation of such pathways is also thought to be important in causing the neurodevelopmental abnormalities seen in disorders such as schizophrenia and autistic disorder, and also may be important in Alzheimer's. Cyclic dipeptides are found in foods such as malt and cocoa and beer. The intestinal yeast Candida albicans also synthesizes cyclic dipeptides. These dipeptides may be activating apoptosis pathways throughout fetal development and postnatal development, leading to some of the changes seen in brain in schizophrenia and in other psychiatric disorders. These compounds should be researched further to see if they play a role in causing these brain changes. In addition, these cyclic dipeptides are considered within the larger context of research on amino acids and other cyclic dipeptides in neurotransmission and neurophysiology. A better understanding of the role of these cyclic dipeptides in psychiatric disorders could lead to strategies for prevention and treatment of these disorders. PMID:24717821
Quantum strategies of quantum measurements
NASA Astrophysics Data System (ADS)
Li, Chuan-Feng; Zhang, Yong-Sheng; Huang, Yun-Feng; Guo, Guang-Can
2001-03-01
In the classical Monty Hall problem, one player can always win with probability 2/3. We generalize the problem to the quantum domain and show that a fair two-party zero-sum game can be carried out if the other player is permitted to adopt quantum measurement strategy.
Sequencing by Cyclic Ligation and Cleavage (CycLiC) directly on a microarray captured template
Mir, Kalim U.; Qi, Hong; Salata, Oleg; Scozzafava, Giuseppe
2009-01-01
Next generation sequencing methods that can be applied to both the resequencing of whole genomes and to the selective resequencing of specific parts of genomes are needed. We describe (i) a massively scalable biochemistry, Cyclical Ligation and Cleavage (CycLiC) for contiguous base sequencing and (ii) apply it directly to a template captured on a microarray. CycLiC uses four color-coded DNA/RNA chimeric oligonucleotide libraries (OL) to extend a primer, a base at a time, along a template. The cycles comprise the steps: (i) ligation of OLs, (ii) identification of extended base by label detection, and (iii) cleavage to remove label/terminator and undetermined bases. For proof-of-principle, we show that the method conforms to design and that we can read contiguous bases of sequence correctly from a template captured by hybridization from solution to a microarray probe. The method is amenable to massive scale-up, miniaturization and automation. Implementation on a microarray format offers the potential for both selection and sequencing of a large number of genomic regions on a single platform. Because the method uses commonly available reagents it can be developed further by a community of users. PMID:19015154
Ground-state information geometry and quantum criticality in an inhomogeneous spin model
NASA Astrophysics Data System (ADS)
Ma, Yu-Quan
2015-09-01
We investigate the ground-state Riemannian metric and the cyclic quantum distance of an inhomogeneous quantum spin-1/2 chain in a transverse field. This model can be diagonalized by using a general canonical transformation to the fermionic Hamiltonian mapped from the spin system. The ground-state Riemannian metric is derived exactly on a parameter manifold ring S1, which is introduced by performing a gauge transformation to the spin Hamiltonian through a twist operator. The cyclic ground-state quantum distance and the second derivative of the ground-state energy are studied in different exchange coupling parameter regions. Particularly, we show that, in the case of exchange coupling parameter Ja = Jb, the quantum ferromagnetic phase can be characterized by an invariant quantum distance and this distance will decay to zero rapidly in the paramagnetic phase. Project supported by the National Natural Science Foundation of China (Grant Nos. 11404023 and 11347131).
Spatial Non-Cyclic Geometric Phase in Neutron Interferometry
Filipp, Stefan; Hasegawa, Yuji; Loidl, Rudolf; Rauch, Helmut
2005-01-01
We present a split-beam neutron interferometric experiment to test the non-cyclic geometric phase tied to the spatial evolution of the system: the subjacent two-dimensional Hilbert space is spanned by the two possible paths in the interferometer and the evolution of the state is controlled by phase shifters and absorbers. A related experiment was reported previously by some of the authors to verify the cyclic spatial geometric phase. The interpretation of this experiment, namely to ascribe a geometric phase to this particular state evolution, has met severe criticism. The extension to non-cyclic evolution manifests the correctness of the interpretation of the previous experiment by means of an explicit calculation of the non-cyclic geometric phase in terms of paths on the Bloch-sphere. The theoretical treatment comprises the cyclic geometric phase as a special case, which is confirmed by experiment. PMID:27308131
Automated mass spectrometric sequence determination of cyclic peptide library members.
Redman, James E; Wilcoxen, Keith M; Ghadiri, M Reza
2003-01-01
Cyclic peptides have come under scrutiny as potential antimicrobial therapeutic agents. Combinatorial split-and-pool synthesis of cyclic peptides can afford single compound per well libraries for antimicrobial screening, new lead identification, and construction of quantitative structure-activity relationships (QSAR). Here, we report a new sequencing protocol for rapid identification of the members of a cyclic peptide library based on automated computer analysis of mass spectra, obviating the need for library encoding/decoding strategies. Furthermore, the software readily integrates with common spreadsheet and database packages to facilitate data visualization and archiving. The utility of the new MS-sequencing approach is demonstrated using sonic spray ionization ion trap MS and MS/MS spectrometry on a single compound per bead cyclic peptide library and validated with individually synthesized pure cyclic D,L-alpha-peptides. PMID:12523832
NASA Astrophysics Data System (ADS)
Mitin, Vladimir; Kochelap, Viacheslav; Stroscio, Michael A.
1999-07-01
Quantum Heterostructures provides a detailed description of the key physical and engineering principles of quantum semiconductor heterostructures. Blending important concepts from physics, materials science, and electrical engineering, it also explains clearly the behavior and operating features of modern microelectronic and optoelectronic devices. The authors begin by outlining the trends that have driven development in this field, most importantly the need for high-performance devices in computer, information, and communications technologies. They then describe the basics of quantum nanoelectronics, including various transport mechanisms. In the latter part of the book, they cover novel microelectronic devices, and optical devices based on quantum heterostructures. The book contains many homework problems and is suitable as a textbook for undergraduate and graduate courses in electrical engineering, physics, or materials science. It will also be of great interest to those involved in research or development in microelectronic or optoelectronic devices.
ERIC Educational Resources Information Center
Aldrovandi, R.: Ferreira, P. Leal
1980-01-01
Discusses the problem of the mathematical pendulum in its classical, semiclassical, and quantum aspects. The energy spectrum and its eigenfunctions are presented under the usual requirement of single valuedness of the solutions. (Author/CS)
NASA Astrophysics Data System (ADS)
Stapp, Henry P.
2012-05-01
Robert Griffiths has recently addressed, within the framework of a `consistent quantum theory' that he has developed, the issue of whether, as is often claimed, quantum mechanics entails a need for faster-than-light transfers of information over long distances. He argues that the putative proofs of this property that involve hidden variables include in their premises some essentially classical-physics-type assumptions that are not entailed by the precepts of quantum mechanics. Thus whatever is proved is not a feature of quantum mechanics, but is a property of a theory that tries to combine quantum theory with quasi-classical features that go beyond what is entailed by quantum theory itself. One cannot logically prove properties of a system by establishing, instead, properties of a system modified by adding properties alien to the original system. Hence Griffiths' rejection of hidden-variable-based proofs is logically warranted. Griffiths mentions the existence of a certain alternative proof that does not involve hidden variables, and that uses only macroscopically described observable properties. He notes that he had examined in his book proofs of this general kind, and concluded that they provide no evidence for nonlocal influences. But he did not examine the particular proof that he cites. An examination of that particular proof by the method specified by his `consistent quantum theory' shows that the cited proof is valid within that restrictive version of quantum theory. An added section responds to Griffiths' reply, which cites general possibilities of ambiguities that might make what is to be proved ill-defined, and hence render the pertinent `consistent framework' ill defined. But the vagaries that he cites do not upset the proof in question, which, both by its physical formulation and by explicit identification, specify the framework to be used. Griffiths confirms the validity of the proof insofar as that pertinent framework is used. The section also shows
Quantum correlations and distinguishability of quantum states
Spehner, Dominique
2014-07-15
A survey of various concepts in quantum information is given, with a main emphasis on the distinguishability of quantum states and quantum correlations. Covered topics include generalized and least square measurements, state discrimination, quantum relative entropies, the Bures distance on the set of quantum states, the quantum Fisher information, the quantum Chernoff bound, bipartite entanglement, the quantum discord, and geometrical measures of quantum correlations. The article is intended both for physicists interested not only by collections of results but also by the mathematical methods justifying them, and for mathematicians looking for an up-to-date introductory course on these subjects, which are mainly developed in the physics literature.
Cyclic AMP-dependent protein kinase activity in Trypanosoma cruzi.
Ulloa, R M; Mesri, E; Esteva, M; Torres, H N; Téllez-Iñón, M T
1988-01-01
A cyclic AMP-dependent protein kinase activity from epimastigote forms of Trypanosoma cruzi was characterized. Cytosolic extracts were chromatographed on DEAE-cellulose columns, giving two peaks of kinase activity, which were eluted at 0.15 M- and 0.32 M-NaCl respectively. The second activity peak was stimulated by nanomolar concentrations of cyclic AMP. In addition, a cyclic AMP-binding protein co-eluted with the second kinase activity peak. Cyclic AMP-dependent protein kinase activity was further purified by gel filtration, affinity chromatography on histone-agarose and cyclic AMP-agarose, as well as by chromatography on CM-Sephadex. The enzyme ('holoenzyme') could be partially dissociated into two different components: 'catalytic' and 'regulatory'. The 'regulatory' component had specific binding for cyclic AMP, and it inhibited phosphotransferase activity of the homologous 'catalytic component' or of the 'catalytic subunit' from bovine heart. Cyclic AMP reversed these inhibitions. A 'holoenzyme preparation' was phosphorylated in the absence of exogenous phosphate acceptor and analysed by polyacrylamide-gel electrophoresis. A 56 kDa band was phosphorylated. The same preparation was analysed by Western blotting, by using polyclonal antibodies to the regulatory subunits of protein kinases type I or II. Both antibodies reacted with the 56 kDa band. Images Fig. 7. Fig. 8. PMID:2848508
Targeting Cyclic Nucleotide Phosphodiesterase in the Heart: Therapeutic Implications
Miller, Clint L.
2010-01-01
The second messengers, cAMP and cGMP, regulate a number of physiological processes in the myocardium, from acute contraction/relaxation to chronic gene expression and cardiac structural remodeling. Emerging evidence suggests that multiple spatiotemporally distinct pools of cyclic nucleotides can discriminate specific cellular functions from a given cyclic nucleotide-mediated signal. Cyclic nucleotide phosphodiesterases (PDEs), by hydrolyzing intracellular cyclic AMP and/or cyclic GMP, control the amplitude, duration, and compartmentation of cyclic nucleotide signaling. To date, more than 60 different isoforms have been described and grouped into 11 broad families (PDE1–PDE11) based on differences in their structure, kinetic and regulatory properties, as well as sensitivity to chemical inhibitors. In the heart, PDE isozymes from at least six families have been investigated. Studies using selective PDE inhibitors and/or genetically manipulated animals have demonstrated that individual PDE isozymes play distinct roles in the heart by regulating unique cyclic nucleotide signaling microdomains. Alterations of PDE activity and/or expression have also been observed in various cardiac disease models, which may contribute to disease progression. Several family-selective PDE inhibitors have been used clinically or pre-clinically for the treatment of cardiac or vascular-related diseases. In this review, we will highlight both recent advances and discrepancies relevant to cardiovascular PDE expression, pathophysiological function, and regulation. In particular, we will emphasize how these properties influence current and future development of PDE inhibitors for the treatment of pathological cardiac remodeling and dysfunction. PMID:20632220
Phorbol esters modulate cyclic AMP accumulation in porcine thyroid cells
Emoto, T.; Kasai, K.; Hiraiwa, M.; Shimoda, S.
1988-01-01
In cultured porcine thyroid cells, during 60 min incubation phorbol 12-myristate 13-acetate (PMA) had no effect on basal cyclic AMP accumulation and slightly stimulated cyclic AMP accumulation evoked by thyroid stimulating hormone (TSH) or forskolin. Cholera toxin-induced cyclic AMP accumulation was significantly stimulated by PMA. On the other hand, cyclic AMP accumulation evoked by prostaglandin E/sub 1/ or E/sub 2/ (PGE/sub 1/ and PGE/sub 2/) was markedly depressed by simultaneous addition of PMA. These opposing effects of PMA on cyclic AMP accumulation evoked by PGE and cholera toxin were observed in a dose-related fashion, with half-maximal effect of around 10/sup -9/ M in either case. The almost same effects of PMA on cyclic AMP accumulation in basal and stimulated conditions were also observed in freshly prepared thyroid cells. The present study was performed in the presence of phosphodiesterase inhibitor, 3-iso-butyl-1-methylxanthine (IBMX), indicating that PMA affected adenylate cyclase activity. Therefore, it is suggested that PMA may modulate the production of cyclic AMP in response to different stimuli, possibly by affecting several sites in the adenylate cyclase complex in thyroid cells.
Automated Search for new Quantum Experiments
NASA Astrophysics Data System (ADS)
Krenn, Mario; Malik, Mehul; Fickler, Robert; Lapkiewicz, Radek; Zeilinger, Anton
2016-03-01
Quantum mechanics predicts a number of, at first sight, counterintuitive phenomena. It therefore remains a question whether our intuition is the best way to find new experiments. Here, we report the development of the computer algorithm Melvin which is able to find new experimental implementations for the creation and manipulation of complex quantum states. Indeed, the discovered experiments extensively use unfamiliar and asymmetric techniques which are challenging to understand intuitively. The results range from the first implementation of a high-dimensional Greenberger-Horne-Zeilinger state, to a vast variety of experiments for asymmetrically entangled quantum states—a feature that can only exist when both the number of involved parties and dimensions is larger than 2. Additionally, new types of high-dimensional transformations are found that perform cyclic operations. Melvin autonomously learns from solutions for simpler systems, which significantly speeds up the discovery rate of more complex experiments. The ability to automate the design of a quantum experiment can be applied to many quantum systems and allows the physical realization of quantum states previously thought of only on paper.
Automated Search for new Quantum Experiments.
Krenn, Mario; Malik, Mehul; Fickler, Robert; Lapkiewicz, Radek; Zeilinger, Anton
2016-03-01
Quantum mechanics predicts a number of, at first sight, counterintuitive phenomena. It therefore remains a question whether our intuition is the best way to find new experiments. Here, we report the development of the computer algorithm Melvin which is able to find new experimental implementations for the creation and manipulation of complex quantum states. Indeed, the discovered experiments extensively use unfamiliar and asymmetric techniques which are challenging to understand intuitively. The results range from the first implementation of a high-dimensional Greenberger-Horne-Zeilinger state, to a vast variety of experiments for asymmetrically entangled quantum states-a feature that can only exist when both the number of involved parties and dimensions is larger than 2. Additionally, new types of high-dimensional transformations are found that perform cyclic operations. Melvin autonomously learns from solutions for simpler systems, which significantly speeds up the discovery rate of more complex experiments. The ability to automate the design of a quantum experiment can be applied to many quantum systems and allows the physical realization of quantum states previously thought of only on paper. PMID:26991161
Hot embossing of cyclic olefin copolymers
NASA Astrophysics Data System (ADS)
Leech, P. W.
2009-05-01
The hot embossing properties of cyclic olefin copolymer (COC) have been examined as a function of comonomer content. Six standard grades of COC with varying norbornene content (61-82 wt%) were used in these experiments in order to provide a range of glass transition temperatures, Tg. All grades of COC exhibited sharp increases in embossed depth over a critical range of temperature. The transition temperature in embossed depth increased linearly with norbornene content for both 35 and 70 µm deep structures. At temperatures above this transition, the dimensions of the embossed patterns were essentially independent of the COC grade, the applied pressure and duration of loading. Channels formed above the transition in a regime of viscous liquid flow were extremely smooth in morphology for all grades. The average surface roughness, Ra, measured at the base of the channels decreased sharply at the transition temperature, with a levelling off at higher temperatures. Grades of COC with a higher norbornene content exhibited extensive micro-cracking during embossing at temperatures close to the transition temperature.
Cyclic Game Dynamics Driven by Iterated Reasoning
Frey, Seth; Goldstone, Robert L.
2013-01-01
Recent theories from complexity science argue that complex dynamics are ubiquitous in social and economic systems. These claims emerge from the analysis of individually simple agents whose collective behavior is surprisingly complicated. However, economists have argued that iterated reasoning–what you think I think you think–will suppress complex dynamics by stabilizing or accelerating convergence to Nash equilibrium. We report stable and efficient periodic behavior in human groups playing the Mod Game, a multi-player game similar to Rock-Paper-Scissors. The game rewards subjects for thinking exactly one step ahead of others in their group. Groups that play this game exhibit cycles that are inconsistent with any fixed-point solution concept. These cycles are driven by a “hopping” behavior that is consistent with other accounts of iterated reasoning: agents are constrained to about two steps of iterated reasoning and learn an additional one-half step with each session. If higher-order reasoning can be complicit in complex emergent dynamics, then cyclic and chaotic patterns may be endogenous features of real-world social and economic systems. PMID:23441191
Cyclicity of some symmetric nilpotent centers
NASA Astrophysics Data System (ADS)
García, Isaac A.
2016-03-01
In this work we present techniques for bounding the cyclicity of a wide class of monodromic nilpotent singularities of symmetric polynomial planar vector fields. The starting point is identifying a broad family of nilpotent symmetric fields for which existence of a center is equivalent to existence of a local analytic first integral, which, unlike the degenerate case, is not true in general for nilpotent singularities. We are able to relate so-called "focus quantities" to the "Poincaré-Lyapunov quantities" arising from the Poincaré first return map. When we apply the method to concrete examples, we show in some cases that the upper bound is sharp. Our approach is based on computational algebra methods for determining a minimal basis (constructed by focus quantities instead of by Poincaré-Lyapunov quantities because of the easier computability of the former) of the associated polynomial Bautin ideal in the parameter space of the family. The case in which the Bautin ideal is not radical is also treated.
Cyclic Vomiting Syndrome: A Functional Disorder
Kaul, Kanwar K.
2015-01-01
Cyclic vomiting syndrome (CVS) is a functional disorder characterized by stereotypical episodes of intense vomiting separated by weeks to months. Although it can occur at any age, the most common age at presentation is 3-7 years. There is no gender predominance. The precise pathophysiology of CVS is not known but a strong association with migraine headaches, in the patient as well as the mother indicates that it may represent a mitochondriopathy. Studies have also suggested the role of an underlying autonomic neuropathy involving the sympathetic nervous system in its pathogenesis. CVS has known triggers in many individuals and avoiding these triggers can help prevent the onset of the episodes. It typically presents in four phases: a prodrome, vomiting phase, recovery phase and an asymptomatic phase until the next episode. Complications such as dehydration and hematemesis from Mallory Wise tear of the esophageal mucosa may occur in more severe cases. Blood and urine tests and abdominal imaging may be indicated depending upon the severity of symptoms. Brain magnetic resonance imaging and upper gastrointestinal endoscopy may also be indicated in certain circumstances. Management of an episode after it has started ('abortive treatment') includes keeping the patient in a dark and quiet room, intravenous hydration, ondansetron, sumatriptan, clonidine, and benzodiazepines. Prophylactic treatment includes cyproheptadine, propranolol and amitriptyline. No mortality has been reported as a direct result of CVS and many children outgrow it over time. A subset may develop other functional disorders like irritable bowel syndrome and migraine headaches. PMID:26770896
Cyclic Vomiting Syndrome: A Functional Disorder.
Kaul, Ajay; Kaul, Kanwar K
2015-12-01
Cyclic vomiting syndrome (CVS) is a functional disorder characterized by stereotypical episodes of intense vomiting separated by weeks to months. Although it can occur at any age, the most common age at presentation is 3-7 years. There is no gender predominance. The precise pathophysiology of CVS is not known but a strong association with migraine headaches, in the patient as well as the mother indicates that it may represent a mitochondriopathy. Studies have also suggested the role of an underlying autonomic neuropathy involving the sympathetic nervous system in its pathogenesis. CVS has known triggers in many individuals and avoiding these triggers can help prevent the onset of the episodes. It typically presents in four phases: a prodrome, vomiting phase, recovery phase and an asymptomatic phase until the next episode. Complications such as dehydration and hematemesis from Mallory Wise tear of the esophageal mucosa may occur in more severe cases. Blood and urine tests and abdominal imaging may be indicated depending upon the severity of symptoms. Brain magnetic resonance imaging and upper gastrointestinal endoscopy may also be indicated in certain circumstances. Management of an episode after it has started ('abortive treatment') includes keeping the patient in a dark and quiet room, intravenous hydration, ondansetron, sumatriptan, clonidine, and benzodiazepines. Prophylactic treatment includes cyproheptadine, propranolol and amitriptyline. No mortality has been reported as a direct result of CVS and many children outgrow it over time. A subset may develop other functional disorders like irritable bowel syndrome and migraine headaches. PMID:26770896
Collagen network strengthening following cyclic tensile loading.
Susilo, Monica E; Paten, Jeffrey A; Sander, Edward A; Nguyen, Thao D; Ruberti, Jeffrey W
2016-02-01
The bulk mechanical properties of tissues are highly tuned to the physiological loads they experience and reflect the hierarchical structure and mechanical properties of their constituent parts. A thorough understanding of the processes involved in tissue adaptation is required to develop multi-scale computational models of tissue remodelling. While extracellular matrix (ECM) remodelling is partly due to the changing cellular metabolic activity, there may also be mechanically directed changes in ECM nano/microscale organization which lead to mechanical tuning. The thermal and enzymatic stability of collagen, which is the principal load-bearing biopolymer in vertebrates, have been shown to be enhanced by force suggesting that collagen has an active role in ECM mechanical properties. Here, we ask how changes in the mechanical properties of a collagen-based material are reflected by alterations in the micro/nanoscale collagen network following cyclic loading. Surprisingly, we observed significantly higher tensile stiffness and ultimate tensile strength, roughly analogous to the effect of work hardening, in the absence of network realignment and alterations to the fibril area fraction. The data suggest that mechanical loading induces stabilizing changes internal to the fibrils themselves or in the fibril-fibril interactions. If such a cell-independent strengthening effect is operational in vivo, then it would be an important consideration in any multiscale computational approach to ECM growth and remodelling. PMID:26855760
Copper regulates cyclic-AMP-dependent lipolysis.
Krishnamoorthy, Lakshmi; Cotruvo, Joseph A; Chan, Jefferson; Kaluarachchi, Harini; Muchenditsi, Abigael; Pendyala, Venkata S; Jia, Shang; Aron, Allegra T; Ackerman, Cheri M; Wal, Mark N Vander; Guan, Timothy; Smaga, Lukas P; Farhi, Samouil L; New, Elizabeth J; Lutsenko, Svetlana; Chang, Christopher J
2016-08-01
Cell signaling relies extensively on dynamic pools of redox-inactive metal ions such as sodium, potassium, calcium and zinc, but their redox-active transition metal counterparts such as copper and iron have been studied primarily as static enzyme cofactors. Here we report that copper is an endogenous regulator of lipolysis, the breakdown of fat, which is an essential process in maintaining body weight and energy stores. Using a mouse model of genetic copper misregulation, in combination with pharmacological alterations in copper status and imaging studies in a 3T3-L1 white adipocyte model, we found that copper regulates lipolysis at the level of the second messenger, cyclic AMP (cAMP), by altering the activity of the cAMP-degrading phosphodiesterase PDE3B. Biochemical studies of the copper-PDE3B interaction establish copper-dependent inhibition of enzyme activity and identify a key conserved cysteine residue in a PDE3-specific loop that is essential for the observed copper-dependent lipolytic phenotype. PMID:27272565
A low-power arcjet cyclic lifetest
NASA Technical Reports Server (NTRS)
Curran, Francis M.; Hardy, Terry L.; Haag, Thomas W.
1987-01-01
A cyclic lifetest of a low power dc arcjet thruster using a hydrogen/nitrogen propellant mixture simulating hydrazine is currently in progress. Over 300 hr of operation have been accumulated to date in 2 hr duty cycles at a power level of about 1.15 kW, approximating that available on commercial communications satellites. A burn-in period was carried out before consistent operation was attained. After this period, the arcjet operated in a very stable fashion from cycle to cycle. At the beginning of each cycle, there was a brief starting transient followed by a rapid rise to a steady-state voltage. The steady-state voltage increased by about 5 V over the first 95 cycles. After this, it increased by only 1 V through the remainder of the test. Thrust measurements taken before the life test and again after the completion of the 144th cycle showed that both thrust, specific impulse, and arc voltage had increased over this period of operation. No life limiting mechanisms were observed during the course of the testing.
Cyclic oxidation evaluation - Approaching application conditions.
NASA Technical Reports Server (NTRS)
Barrett, C. A.; Evans, E. B.
1973-01-01
Review of 1000 to 1200 C cyclic oxidation testing conducted on potential aircraft gas turbine Ni-, Co-, and Fe-base alloys. Furnace and burner rig testing are discussed, and the results are compared for selected alloys. The alloys fall into two groups, depending on their Cr and Al contents. One group forms mainly Cr2O3/chromite spinel scale(s), while the other forms alpha Al2O3/aluminate spinel scale(s). Spalling on thermal cycling leading to increased metal consumption is associated with the appearance of a chromite spinel. In the case of high-velocity burner rig tests this chromite forming tendency is reinforced by Cr2O3 vaporization depleting Cr in the alloy. In both types of tests, specific weight change is used as an indirect indicator of metal attack, since direct metal loss measurements require destructive analysis. An alternative nondestructive metal loss estimating parameter, based on a tentative mass balance gravimetric approach, shows some potential.
Cyclic flow underground coal gasification process
Bissett, Larry A.
1978-01-01
The present invention is directed to a method of in situ coal gasification for providing the product gas with an enriched concentration of carbon monoxide. The method is practiced by establishing a pair of combustion zones in spaced-apart boreholes within a subterranean coal bed and then cyclically terminating the combustion in the first of the two zones to establish a forward burn in the coal bed so that while an exothermic reaction is occurring in the second combustion zone to provide CO.sub.2 -laden product gas, an endothermic CO-forming reaction is occurring in the first combustion zone between the CO.sub.2 -laden gas percolating thereinto and the hot carbon in the wall defining the first combustion zone to increase the concentration of CO in the product gas. When the endothermic reaction slows to a selected activity the roles of the combustion zones are reversed by re-establishing an exothermic combustion reaction in the first zone and terminating the combustion in the second zone.
Quantum Particles From Quantum Information
NASA Astrophysics Data System (ADS)
Görnitz, T.; Schomäcker, U.
2012-08-01
Many problems in modern physics demonstrate that for a fundamental entity a more general conception than quantum particles or quantum fields are necessary. These concepts cannot explain the phenomena of dark energy or the mind-body-interaction. Instead of any kind of "small elementary building bricks", the Protyposis, an abstract and absolute quantum information, free of special denotation and open for some purport, gives the solution in the search for a fundamental substance. However, as long as at least relativistic particles are not constructed from the Protyposis, such an idea would remain in the range of natural philosophy. Therefore, the construction of relativistic particles without and with rest mass from quantum information is shown.
The mycotoxin definition reconsidered towards fungal cyclic depsipeptides.
Taevernier, Lien; Wynendaele, Evelien; De Vreese, Leen; Burvenich, Christian; De Spiegeleer, Bart
2016-04-01
Currently, next to the major classes, cyclic depsipeptides beauvericin and enniatins are also positioned as mycotoxins. However, as there are hundreds more fungal cyclic depsipeptides already identified, should these not be considered as mycotoxins as well? The current status of the mycotoxin definition revealed a lack of consistency, leading to confusion about what compounds should be called mycotoxins. Because this is of pivotal importance in risk assessment prioritization, a clear and quantitatively expressed mycotoxin definition is proposed, based on data of widely accepted mycotoxins. Finally, this definition is applied to a set of fungal cyclic depsipeptides, revealing that some of these should indeed be considered as mycotoxins. PMID:26963720