Thermal Quantum Discord and Super Quantum Discord Teleportation Via a Two-Qubit Spin-Squeezing Model
NASA Astrophysics Data System (ADS)
Ahadpour, S.; Mirmasoudi, F.
2018-04-01
We study thermal quantum correlations (quantum discord and super quantum discord) in a two-spin model in an external magnetic field and obtain relations between them and entanglement. We study their dependence on the magnetic field, the strength of the spin squeezing, and the temperature in detail. One interesting result is that when the entanglement suddenly disappears, quantum correlations still survive. We study thermal quantum teleportation in the framework of this model. The main goal is investigating the possibility of increasing the thermal quantum correlations of a teleported state in the presence of a magnetic field, strength of the spin squeezing, and temperature. We note that teleportation of quantum discord and super quantum discord can be realized over a larger temperature range than teleportation of entanglement. Our results show that quantum discord and super quantum discord can be a suitable measure for controlling quantum teleportation with fidelity. Moreover, the presence of entangled states is unnecessary for the exchange of quantum information.
One-way unlocalizable quantum discord
NASA Astrophysics Data System (ADS)
Xi, Zhengjun; Fan, Heng; Li, Yongming
2012-05-01
In this paper, we present the concept of the one-way unlocalizable quantum discord and investigate its properties. We provide a polygamy inequality for it in a tripartite pure quantum system of arbitrary dimension. Several tradeoff relations between the one-way unlocalizable quantum discord and other correlations are given. If the von Neumann measurement is made on a part of the system, we give two expressions of the one-way unlocalizable quantum discord in terms of partial distillable entanglement and quantum disturbance. Finally, we also provide a lower bound for bipartite shareability of quantum correlation beyond entanglement in a tripartite system.
Relating quantum discord with the quantum dense coding capacity
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wang, Xin; Qiu, Liang, E-mail: lqiu@cumt.edu.cn; Li, Song
2015-01-15
We establish the relations between quantum discord and the quantum dense coding capacity in (n + 1)-particle quantum states. A necessary condition for the vanishing discord monogamy score is given. We also find that the loss of quantum dense coding capacity due to decoherence is bounded below by the sum of quantum discord. When these results are restricted to three-particle quantum states, some complementarity relations are obtained.
Quantum discord and Maxwell's demons
DOE Office of Scientific and Technical Information (OSTI.GOV)
Zurek, Wojciech Hubert
2003-01-01
Quantum discord was proposed as an information-theoretic measure of the 'quantumness' of correlations. I show that discord determines the difference between the efficiency of quantum and classical Maxwell's demons - that is, entities that can or cannot measure nonlocal observables or carry out conditional quantum operations - in extracting work from collections of correlated quantum systems.
Computing quantum discord is NP-complete
NASA Astrophysics Data System (ADS)
Huang, Yichen
2014-03-01
We study the computational complexity of quantum discord (a measure of quantum correlation beyond entanglement), and prove that computing quantum discord is NP-complete. Therefore, quantum discord is computationally intractable: the running time of any algorithm for computing quantum discord is believed to grow exponentially with the dimension of the Hilbert space so that computing quantum discord in a quantum system of moderate size is not possible in practice. As by-products, some entanglement measures (namely entanglement cost, entanglement of formation, relative entropy of entanglement, squashed entanglement, classical squashed entanglement, conditional entanglement of mutual information, and broadcast regularization of mutual information) and constrained Holevo capacity are NP-hard/NP-complete to compute. These complexity-theoretic results are directly applicable in common randomness distillation, quantum state merging, entanglement distillation, superdense coding, and quantum teleportation; they may offer significant insights into quantum information processing. Moreover, we prove the NP-completeness of two typical problems: linear optimization over classical states and detecting classical states in a convex set, providing evidence that working with classical states is generically computationally intractable.
NASA Astrophysics Data System (ADS)
Nguyen, Nga T. T.; Joynt, Robert
2017-04-01
Quantum discord is an important measure of quantum correlations that can serve as a resource for certain types of quantum information processing. Like entanglement, discord is subject to destruction by external noise. The routes by which this destruction can take place depends on the shape of the hypersurface of zero discord C in the space of generalized Bloch vectors. For 2 qubits, we show that with a few points subtracted, this hypersurface is a simply-connected 9-dimensional manifold embedded in a 15-dimensional background space. We do this by constructing an explicit homeomorphism from a known manifold to the subtracted version of C . We also construct a coordinate map on C that can be used for integration or other purposes. This topological characterization of C has important implications for the classification of the possible time evolutions of discord in physical models. The classification for discord contrasts sharply with the possible evolutions of entanglement. We classify the possible joint evolutions of entanglement and discord. There are 9 allowed categories: 6 categories for a Markovian process and 3 categories for a non-Markovian process, respectively. We illustrate these conclusions with an anisotropic XY spin model. All 9 categories can be obtained by adjusting parameters in this model.
Collapse–revival of quantum discord and entanglement
DOE Office of Scientific and Technical Information (OSTI.GOV)
Yan, Xue-Qun, E-mail: xqyan867@tom.com; Zhang, Bo-Ying
2014-10-15
In this paper the correlations dynamics of two atoms in the case of a micromaser-type system is investigated. Our results predict certain quasi-periodic collapse and revival phenomena for quantum discord and entanglement when the field is in Fock state and the two atoms are initially in maximally mixed state, which is a special separable state. Our calculations also show that the oscillations of the time evolution of both quantum discord and entanglement are almost in phase and they both have similar evolution behavior in some time range. The fact reveals the consistency of quantum discord and entanglement in some dynamicalmore » aspects. - Highlights: • The correlations dynamics of two atoms in the case of a micromaser-type system is investigated. • A quasi-periodic collapse and revival phenomenon for quantum discord and entanglement is reported. • A phenomenon of correlations revivals different from that of non-Markovian dynamics is revealed. • The oscillations of time evolution of both quantum discord and entanglement are almost in phase in our system. • Quantum discord and entanglement have similar evolution behavior in some time range.« less
Quantum discord, local operations, and Maxwell's demons
DOE Office of Scientific and Technical Information (OSTI.GOV)
Brodutch, Aharon; Terno, Daniel R.
2010-06-15
Quantum discord was proposed as a measure of the quantumness of correlations. There are at least three different discordlike quantities, two of which determine the difference between the efficiencies of a Szilard's engine under different sets of restrictions. The three discord measures vanish simultaneously. We introduce an easy way to test for zero discord, relate it to the Cerf-Adami conditional entropy and show that there is no simple relation between the discord and the local distinguishability.
Steady state quantum discord for circularly accelerated atoms
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hu, Jiawei, E-mail: hujiawei@nbu.edu.cn; Yu, Hongwei, E-mail: hwyu@hunnu.edu.cn; Synergetic Innovation Center for Quantum Effects and Applications, Hunan Normal University, Changsha, Hunan 410081
2015-12-15
We study, in the framework of open quantum systems, the dynamics of quantum entanglement and quantum discord of two mutually independent circularly accelerated two-level atoms in interaction with a bath of fluctuating massless scalar fields in the Minkowski vacuum. We assume that the two atoms rotate synchronically with their separation perpendicular to the rotating plane. The time evolution of the quantum entanglement and quantum discord of the two-atom system is investigated. For a maximally entangled initial state, the entanglement measured by concurrence diminishes to zero within a finite time, while the quantum discord can either decrease monotonically to an asymptoticmore » value or diminish to zero at first and then followed by a revival depending on whether the initial state is antisymmetric or symmetric. When both of the two atoms are initially excited, the generation of quantum entanglement shows a delayed feature, while quantum discord is created immediately. Remarkably, the quantum discord for such a circularly accelerated two-atom system takes a nonvanishing value in the steady state, and this is distinct from what happens in both the linear acceleration case and the case of static atoms immersed in a thermal bath.« less
NASA Astrophysics Data System (ADS)
Roszak, K.; Cywiński, Ł.
2015-10-01
We study quantum teleportation via Bell-diagonal mixed states of two qubits in the context of the intrinsic properties of the quantum discord. We show that when the quantum-correlated state of the two qubits is used for quantum teleportation, the character of the teleportation efficiency changes substantially depending on the Bell-diagonal-state parameters, which can be seen when the worst-case-scenario or best-case-scenario fidelity is studied. Depending on the parameter range, one of two types of single-qubit states is hardest/easiest to teleport. The transition between these two parameter ranges coincides exactly with the transition between the range of classical correlation decay and quantum correlation decay characteristic for the evolution of the quantum discord. The correspondence provides a physical interpretation for the prominent feature of the decay of the quantum discord.
Quantum Discord Preservation for Two Quantum-Correlated Qubits in Two Independent Reserviors
NASA Astrophysics Data System (ADS)
Xu, Lan
2018-03-01
We investigate the dynamics of quantum discord using an exactly solvable model where two qubits coupled to independent thermal environments. The quantum discord is employed as a non-classical correlation quantifier. By studying the quantum discord of a class of initial states, we find discord remains preserve for a finite time. The effects of the temperature, initial-state parameter, system-reservoir coupling constant and temperature difference parameter of the two independent reserviors are also investigated. We discover that the quantum nature loses faster in high temperature, however, one can extend the time of quantum nature by choosing smaller system-reservoir coupling constant, larger certain initial-state parameter and larger temperature difference parameter.
The sudden death and sudden birth of quantum discord.
Xia, Wei; Hou, Jin-Xing; Wang, Xiao-Hui; Liu, Si-Yuan
2018-03-28
The interaction of quantum system and its environment brings out abundant quantum phenomenons. The sudden death of quantum resources, including entanglement, quantum discord and coherence, have been studied from the perspective of quantum breaking channels (QBC). QBC of quantum resources reveal the common features of quantum resources. The definition of QBC implies the relationship between quantum resources. However, sudden death of quantum resources can also appear under some other quantum channels. We consider the dynamics of Bell-diagonal states under a stochastic dephasing noise along the z-direction, and the sudden death and sudden birth of quantum discord are investigated. Next we explain this phenomenon from the geometric structure of quantum discord. According to the above results, the states with sudden death and sudden birth can be filtered in three-parameter space. Then we provide two necessary conditions to judge which kind of noise channels can make Bell-diagonal states sudden death and sudden birth. Moreover, the relation between quantum discord and coherence indicates that the sudden death and sudden birth of quantum discord implies the sudden death and sudden birth of coherence in an optimal basis.
Global quantum discord and matrix product density operators
NASA Astrophysics Data System (ADS)
Huang, Hai-Lin; Cheng, Hong-Guang; Guo, Xiao; Zhang, Duo; Wu, Yuyin; Xu, Jian; Sun, Zhao-Yu
2018-06-01
In a previous study, we have proposed a procedure to study global quantum discord in 1D chains whose ground states are described by matrix product states [Z.-Y. Sun et al., Ann. Phys. 359, 115 (2015)]. In this paper, we show that with a very simple generalization, the procedure can be used to investigate quantum mixed states described by matrix product density operators, such as quantum chains at finite temperatures and 1D subchains in high-dimensional lattices. As an example, we study the global discord in the ground state of a 2D transverse-field Ising lattice, and pay our attention to the scaling behavior of global discord in 1D sub-chains of the lattice. We find that, for any strength of the magnetic field, global discord always shows a linear scaling behavior as the increase of the length of the sub-chains. In addition, global discord and the so-called "discord density" can be used to indicate the quantum phase transition in the model. Furthermore, based upon our numerical results, we make some reliable predictions about the scaling of global discord defined on the n × n sub-squares in the lattice.
Discord as a quantum resource for bi-partite communication
NASA Astrophysics Data System (ADS)
Chrzanowski, Helen M.; Gu, Mile; Assad, Syed M.; Symul, Thomas; Modi, Kavan; Ralph, Timothy C.; Vedral, Vlatko; Lam, Ping Koy
2014-12-01
Coherent interactions that generate negligible entanglement can still exhibit unique quantum behaviour. This observation has motivated a search beyond entanglement for a complete description of all quantum correlations. Quantum discord is a promising candidate. Here, we experimentally demonstrate that under certain measurement constraints, discord between bipartite systems can be consumed to encode information that can only be accessed by coherent quantum interactions. The inability to access this information by any other means allows us to use discord to directly quantify this `quantum advantage'.
Sudden change of geometric quantum discord in finite temperature reservoirs
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hu, Ming-Liang, E-mail: mingliang0301@163.com; Sun, Jian
2015-03-15
We investigate sudden change (SC) behaviors of the distance-based measures of geometric quantum discords (GQDs) for two non-interacting qubits subject to the two-sided and the one-sided thermal reservoirs. We found that the GQDs defined by different distances exhibit different SCs, and thus the SCs are the combined result of the chosen discord measure and the property of a state. We also found that the thermal reservoir may generate states having different orderings related to different GQDs. These inherent differences of the GQDs reveal that they are incompatible in characterizing quantum correlations both quantitatively and qualitatively. - Highlights: • Comparable studymore » of different distance-based geometric quantum discords. • Evolution of the geometric quantum discords in finite temperature reservoirs. • Different geometric quantum discords exhibit distinct sudden changes. • Nonunique states ordering imposed by different geometric quantum discords.« less
Quantum Discord Determines the Interferometric Power of Quantum States
NASA Astrophysics Data System (ADS)
Girolami, Davide; Souza, Alexandre M.; Giovannetti, Vittorio; Tufarelli, Tommaso; Filgueiras, Jefferson G.; Sarthour, Roberto S.; Soares-Pinto, Diogo O.; Oliveira, Ivan S.; Adesso, Gerardo
2014-05-01
Quantum metrology exploits quantum mechanical laws to improve the precision in estimating technologically relevant parameters such as phase, frequency, or magnetic fields. Probe states are usually tailored to the particular dynamics whose parameters are being estimated. Here we consider a novel framework where quantum estimation is performed in an interferometric configuration, using bipartite probe states prepared when only the spectrum of the generating Hamiltonian is known. We introduce a figure of merit for the scheme, given by the worst-case precision over all suitable Hamiltonians, and prove that it amounts exactly to a computable measure of discord-type quantum correlations for the input probe. We complement our theoretical results with a metrology experiment, realized in a highly controllable room-temperature nuclear magnetic resonance setup, which provides a proof-of-concept demonstration for the usefulness of discord in sensing applications. Discordant probes are shown to guarantee a nonzero phase sensitivity for all the chosen generating Hamiltonians, while classically correlated probes are unable to accomplish the estimation in a worst-case setting. This work establishes a rigorous and direct operational interpretation for general quantum correlations, shedding light on their potential for quantum technology.
Quantum Discord for d⊗2 Systems
Ma, Zhihao; Chen, Zhihua; Fanchini, Felipe Fernandes; Fei, Shao-Ming
2015-01-01
We present an analytical solution for classical correlation, defined in terms of linear entropy, in an arbitrary system when the second subsystem is measured. We show that the optimal measurements used in the maximization of the classical correlation in terms of linear entropy, when used to calculate the quantum discord in terms of von Neumann entropy, result in a tight upper bound for arbitrary systems. This bound agrees with all known analytical results about quantum discord in terms of von Neumann entropy and, when comparing it with the numerical results for 106 two-qubit random density matrices, we obtain an average deviation of order 10−4. Furthermore, our results give a way to calculate the quantum discord for arbitrary n-qubit GHZ and W states evolving under the action of the amplitude damping noisy channel. PMID:26036771
Quantum discord of two-qubit X states
DOE Office of Scientific and Technical Information (OSTI.GOV)
Chen Qing; Yu Sixia; Hefei National Laboratory for Physical Sciences at Microscale and Department of Modern Physics, University of Science and Technology of China, Hefei, 230026 Anhui
Quantum discord provides a measure for quantifying quantum correlations beyond entanglement and is very hard to compute even for two-qubit states because of the minimization over all possible measurements. Recently a simple algorithm to evaluate the quantum discord for two-qubit X states was proposed by Ali, Rau, and Alber [Phys. Rev. A 81, 042105 (2010)] with minimization taken over only a few cases. Here we shall at first identify a class of X states, whose quantum discord can be evaluated analytically without any minimization, for which their algorithm is valid, and also identify a family of X states for whichmore » their algorithm fails. And then we demonstrate that this special family of X states provides furthermore an explicit example for the inequivalence between the minimization over positive operator-valued measures and that over von Neumann measurements.« less
NASA Astrophysics Data System (ADS)
Joya, Wajid; Khan, Salman; Khalid Khan, M.; Alam, Sher
2017-05-01
The behavior of bipartite quantum discord (BQD) and tripartite quantum discord (TQD) in the Heisenberg XXZ spins chain is investigated with the increasing size of the system using the approach of the quantum renormalization group method. Analytical relations for both BQD and TQD are obtained and the results are checked through numerical optimization. In the thermodynamics limit, both types of discord exhibit quantum phase transition (QPT). The boundary of QPT links the phases of saturated discord and zero discord. The first derivative of both discords becomes discontinuous at the critical point, which corresponds to the second-order phase transition. Qualitatively identical, the amount of saturated BQD strongly depends on the relative positions of spins inside a block. TQD can be a better candidate than BQD both for analyzing QPT and implementing quantum information tasks. The scaling behavior in the vicinity of the critical point is discussed.
Distribution of geometric quantum discord in photon-added coherent states
NASA Astrophysics Data System (ADS)
Daoud, M.; Kaydi, W.; El Hadfi, H.
2015-12-01
In this paper, we examine the influence of photon excitation on the monogamy property of quantum discord in tripartite coherent states of Greenberger-Horne-Zeilinger (GHZ) type. The Hilbert-Schmidt norm is used as quantifier of pairwise quantum correlations. The geometric quantum discord in all bipartite subsystems are explicitly given. We show that the geometric discord is monogamous for any photon excitation order.
Quantum discord as a resource for quantum cryptography.
Pirandola, Stefano
2014-11-07
Quantum discord is the minimal bipartite resource which is needed for a secure quantum key distribution, being a cryptographic primitive equivalent to non-orthogonality. Its role becomes crucial in device-dependent quantum cryptography, where the presence of preparation and detection noise (inaccessible to all parties) may be so strong to prevent the distribution and distillation of entanglement. The necessity of entanglement is re-affirmed in the stronger scenario of device-independent quantum cryptography, where all sources of noise are ascribed to the eavesdropper.
Quantum discord as a resource for quantum cryptography
Pirandola, Stefano
2014-01-01
Quantum discord is the minimal bipartite resource which is needed for a secure quantum key distribution, being a cryptographic primitive equivalent to non-orthogonality. Its role becomes crucial in device-dependent quantum cryptography, where the presence of preparation and detection noise (inaccessible to all parties) may be so strong to prevent the distribution and distillation of entanglement. The necessity of entanglement is re-affirmed in the stronger scenario of device-independent quantum cryptography, where all sources of noise are ascribed to the eavesdropper. PMID:25378231
Post-Markovian dynamics of quantum correlations: entanglement versus discord
NASA Astrophysics Data System (ADS)
Mohammadi, Hamidreza
2017-02-01
Dynamics of an open two-qubit system is investigated in the post-Markovian regime, where the environments have a short-term memory. Each qubit is coupled to separate environment which is held in its own temperature. The inter-qubit interaction is modeled by XY-Heisenberg model in the presence of spin-orbit interaction and inhomogeneous magnetic field. The dynamical behavior of entanglement and discord has been considered. The results show that quantum discord is more robust than quantum entanglement, during the evolution. Also the asymmetric feature of quantum discord can be monitored by introducing the asymmetries due to inhomogeneity of magnetic field and temperature difference between the reservoirs. By employing proper parameters of the model, it is possible to maintain nonvanishing quantum correlation at high degree of temperature. The results can provide a useful recipe for studying dynamical behavior of two-qubit systems such as trapped spin electrons in coupled quantum dots.
Complementarity of quantum discord and classically accessible information
Zwolak, Michael P.; Zurek, Wojciech H.
2013-05-20
The sum of the Holevo quantity (that bounds the capacity of quantum channels to transmit classical information about an observable) and the quantum discord (a measure of the quantumness of correlations of that observable) yields an observable-independent total given by the quantum mutual information. This split naturally delineates information about quantum systems accessible to observers – information that is redundantly transmitted by the environment – while showing that it is maximized for the quasi-classical pointer observable. Other observables are accessible only via correlations with the pointer observable. In addition, we prove an anti-symmetry property relating accessible information and discord. Itmore » shows that information becomes objective – accessible to many observers – only as quantum information is relegated to correlations with the global environment, and, therefore, locally inaccessible. Lastly, the resulting complementarity explains why, in a quantum Universe, we perceive objective classical reality while flagrantly quantum superpositions are out of reach.« less
Hierarchy of Efficiently Computable and Faithful Lower Bounds to Quantum Discord
NASA Astrophysics Data System (ADS)
Piani, Marco
2016-08-01
Quantum discord expresses a fundamental nonclassicality of correlations that is more general than entanglement, but that, in its standard definition, is not easily evaluated. We derive a hierarchy of computationally efficient lower bounds to the standard quantum discord. Every nontrivial element of the hierarchy constitutes by itself a valid discordlike measure, based on a fundamental feature of quantum correlations: their lack of shareability. Our approach emphasizes how the difference between entanglement and discord depends on whether shareability is intended as a static property or as a dynamical process.
NASA Astrophysics Data System (ADS)
Daoud, M.; Ahl Laamara, R.
2012-07-01
We give the explicit expressions of the pairwise quantum correlations present in superpositions of multipartite coherent states. A special attention is devoted to the evaluation of the geometric quantum discord. The dynamics of quantum correlations under a dephasing channel is analyzed. A comparison of geometric measure of quantum discord with that of concurrence shows that quantum discord in multipartite coherent states is more resilient to dissipative environments than is quantum entanglement. To illustrate our results, we consider some special superpositions of Weyl-Heisenberg, SU(2) and SU(1,1) coherent states which interpolate between Werner and Greenberger-Horne-Zeilinger states.
Quantum Discord in Photon-Added Glauber Coherent States of GHZ-Type
NASA Astrophysics Data System (ADS)
Daoud, M.; Kaydi, W.; El Hadfi, H.
2015-11-01
We investigate the influence of photon excitations on quantum correlations in tripartite Glauber coherent states of Greenberger-Horne-Zeilinger type (GHZ-type). The pairwise correlations are measured by means of the entropy-based quantum discord. We also analyze the monogamy property of quantum discord in this class of tripartite states in terms of the strength of Glauber coherent states and the photon excitation order.
Global quantum discord and quantum phase transition in XY model
DOE Office of Scientific and Technical Information (OSTI.GOV)
Liu, Si-Yuan; Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190; Zhang, Yu-Ran, E-mail: yrzhang@iphy.ac.cn
We study the relationship between the behavior of global quantum correlations and quantum phase transitions in XY model. We find that the two kinds of phase transitions in the studied model can be characterized by the features of global quantum discord (GQD) and the corresponding quantum correlations. We demonstrate that the maximum of the sum of all the nearest neighbor bipartite GQDs is effective and accurate for signaling the Ising quantum phase transition, in contrast, the sudden change of GQD is very suitable for characterizing another phase transition in the XY model. This may shed lights on the study ofmore » properties of quantum correlations in different quantum phases.« less
NASA Astrophysics Data System (ADS)
He, Juan; Wu, Tao; Ye, Liu
2013-10-01
In this paper, we study the dynamics of quantum discord and entanglement of three identical two-level atoms simultaneously resonantly interacting with three spatially separate single-mode of high- Q cavities respectively. Taking advantage of the depiction quantum discord and entanglement of formation (EoF), we conclude that the discord and entanglement of atoms and cavities can be mediated by changing some parameters and the maximum values of discord and entanglement are independent on the couplings of cavities and atoms. In particular, there also exists quantum discord sudden death as well as entanglement sudden death and the time interval of the former is shorter than that of the later in the proposed quantum system. It is shown that the discord and entanglement of any two atoms among three atoms can be transferred to the corresponding cavities, and there exists discord and entanglement exchanging between the atoms and the corresponding cavities.
Hilbert-Schmidt Measure of Pairwise Quantum Discord for Three-Qubit X States
NASA Astrophysics Data System (ADS)
Daoud, M.; Laamara, R. Ahl; Seddik, S.
2015-10-01
The Hilbert-Schmidt distance between a mixed three-qubit state and its closest state is used to quantify the amount of pairwise quantum correlations in a tripartite system. Analytical expressions of geometric quantum discord are derived. A particular attention is devoted to two special classes of three-qubit X states. They include three-qubit states of W, GHZ and Bell type. We also discuss the monogamy property of geometric quantum discord in some mixed three-qubit systems.
Decoherence, discord, and the quantum master equation for cosmological perturbations
NASA Astrophysics Data System (ADS)
Hollowood, Timothy J.; McDonald, Jamie I.
2017-05-01
We examine environmental decoherence of cosmological perturbations in order to study the quantum-to-classical transition and the impact of noise on entanglement during inflation. Given an explicit interaction between the system and environment, we derive a quantum master equation for the reduced density matrix of perturbations, drawing parallels with quantum Brownian motion, where we see the emergence of fluctuation and dissipation terms. Although the master equation is not in Lindblad form, we see how typical solutions exhibit positivity on super-horizon scales, leading to a physically meaningful density matrix. This allows us to write down a Langevin equation with stochastic noise for the classical trajectories which emerge from the quantum system on super-horizon scales. In particular, we find that environmental decoherence increases in strength as modes exit the horizon, with the growth driven essentially by white noise coming from local contributions to environmental correlations. Finally, we use our master equation to quantify the strength of quantum correlations as captured by discord. We show that environmental interactions have a tendency to decrease the size of the discord and that these effects are determined by the relative strength of the expansion rate and interaction rate of the environment. We interpret this in terms of the competing effects of particle creation versus environmental fluctuations, which tend to increase and decrease the discord respectively.
Sadhukhan, Debasis; Roy, Sudipto Singha; Rakshit, Debraj; Prabhu, R; Sen De, Aditi; Sen, Ujjwal
2016-01-01
Classical correlation functions of ground states typically decay exponentially and polynomially, respectively, for gapped and gapless short-range quantum spin systems. In such systems, entanglement decays exponentially even at the quantum critical points. However, quantum discord, an information-theoretic quantum correlation measure, survives long lattice distances. We investigate the effects of quenched disorder on quantum correlation lengths of quenched averaged entanglement and quantum discord, in the anisotropic XY and XYZ spin glass and random field chains. We find that there is virtually neither reduction nor enhancement in entanglement length while quantum discord length increases significantly with the introduction of the quenched disorder.
Purified discord and multipartite entanglement
DOE Office of Scientific and Technical Information (OSTI.GOV)
Brown, Eric G.; Webster, Eric J.; Martín-Martínez, Eduardo, E-mail: emmfis@gmail.com
2013-10-15
We study bipartite quantum discord as a manifestation of a multipartite entanglement structure in the tripartite purified system. In particular, we find that bipartite quantum discord requires the presence of both bipartite and tripartite entanglement in the purification. This allows one to understand the asymmetry of quantum discord, D(A,B)≠D(B,A) in terms of entanglement monogamy. As instructive special cases, we study discord for qubits and Gaussian states in detail. As a result of this we shed new light on a counterintuitive property of Gaussian states: the presence of classical correlations necessarily requires the presence of quantum correlations. Finally, our results alsomore » shed new light on a protocol for remote activation of entanglement by a third party. -- Highlights: •Bipartite quantum discord as a manifestation of multipartite entanglement. •Relevance of quantum discord as a utilizable resource for quantum info. tasks. •Quantum discord manifests itself in entanglement in the purified state. •Relation between asymmetry of discord and entanglement monogamy. •Protocol for remote activation of entanglement by a third party.« less
NASA Astrophysics Data System (ADS)
Kenfack, Lionel Tenemeza; Tchoffo, Martin; Fai, Lukong Cornelius
2017-02-01
We address the dynamics of quantum correlations, including entanglement and quantum discord of a three-qubit system interacting with a classical pure dephasing random telegraph noise (RTN) in three different physical environmental situations (independent, mixed and common environments). Two initial entangled states of the system are examined, namely the Greenberger-Horne-Zeilinger (GHZ)- and Werner (W)-type states. The classical noise is introduced as a stochastic process affecting the energy splitting of the qubits. With the help of suitable measures of tripartite entanglement (entanglement witnesses and lower bound of concurrence) and quantum discord (global quantum discord and quantum dissension), we show that the evolution of quantum correlations is not only affected by the type of the system-environment interaction but also by the input configuration of the qubits and the memory properties of the environmental noise. Indeed, depending on the memory properties of the environmental noise and the initial state considered, we find that independent, common and mixed environments can play opposite roles in preserving quantum correlations, and that the sudden death and revival phenomena or the survival of quantum correlations may occur. On the other hand, we also show that the W-type state has strong dynamics under this noise than the GHZ-type ones.
Shapiro, Jeffrey H.; Venkatraman, Dheera; Wong, Franco N. C.
2013-01-01
Ragy and Adesso argue that quantum discord is involved in the formation of a pseudothermal ghost image. We show that quantum discord plays no role in spatial light modulator ghost imaging, i.e., ghost-image formation based on structured illumination realized with laser light that has undergone spatial light modulation by the output from a pseudorandom number generator. Our analysis thus casts doubt on the degree to which quantum discord is necessary for ghost imaging. PMID:23673426
Quantum discord bounds the amount of distributed entanglement.
Chuan, T K; Maillard, J; Modi, K; Paterek, T; Paternostro, M; Piani, M
2012-08-17
The ability to distribute quantum entanglement is a prerequisite for many fundamental tests of quantum theory and numerous quantum information protocols. Two distant parties can increase the amount of entanglement between them by means of quantum communication encoded in a carrier that is sent from one party to the other. Intriguingly, entanglement can be increased even when the exchanged carrier is not entangled with the parties. However, in light of the defining property of entanglement stating that it cannot increase under classical communication, the carrier must be quantum. Here we show that, in general, the increase of relative entropy of entanglement between two remote parties is bounded by the amount of nonclassical correlations of the carrier with the parties as quantified by the relative entropy of discord. We study implications of this bound, provide new examples of entanglement distribution via unentangled states, and put further limits on this phenomenon.
Observing the operational significance of discord consumption
NASA Astrophysics Data System (ADS)
Gu, Mile; Chrzanowski, Helen M.; Assad, Syed M.; Symul, Thomas; Modi, Kavan; Ralph, Timothy C.; Vedral, Vlatko; Lam, Ping Koy
2012-09-01
Coherent interactions that generate negligible entanglement can still exhibit unique quantum behaviour. This observation has motivated a search beyond entanglement for a complete description of all quantum correlations. Quantum discord is a promising candidate. Here, we demonstrate that under certain measurement constraints, discord between bipartite systems can be consumed to encode information that can only be accessed by coherent quantum interactions. The inability to access this information by any other means allows us to use discord to directly quantify this `quantum advantage'. We experimentally encode information within the discordant correlations of two separable Gaussian states. The amount of extra information recovered by coherent interaction is quantified and directly linked with the discord consumed during encoding. No entanglement exists at any point of this experiment. Thus we introduce and demonstrate an operational method to use discord as a physical resource.
What can we learn from the dynamics of entanglement and quantum discord in the Tavis-Cummings model?
NASA Astrophysics Data System (ADS)
Restrepo, Juliana; Rodriguez, Boris A.
We revisit the problem of the dynamics of quantum correlations in the exact Tavis-Cummings model. We show that many of the dynamical features of quantum discord attributed to dissipation are already present in the exact framework and are due to the well known non-linearities in the model and to the choice of initial conditions. Through a comprehensive analysis, supported by explicit analytical calculations, we find that the dynamics of entanglement and quantum discord are far from being trivial or intuitive. In this context, we find states that are indistinguishable from the point of view of entanglement and distinguishable from the point of view of quantum discord, states where the two quantifiers give opposite information and states where they give roughly the same information about correlations at a certain time. Depending on the initial conditions, this model exhibits a fascinating range of phenomena that can be used for experimental purposes such as: Robust states against change of manifold or dissipation, tunable entanglement states and states with a counterintuitive sudden birth as the number of photons increase. We furthermore propose an experiment called quantum discord gates where discord is zero or non-zero depending on the number of photons. This work was supported by the Vicerrectoria de Investigacion of the Universidad Antonio Narino, Colombia under Project Number 20141031 and by the Departamento Administrativo de Ciencia, Tecnologia e Innovacion (COLCIENCIAS) of Colombia under Grant Number.
Quantum Discord in a Spin System with Symmetry Breaking
NASA Astrophysics Data System (ADS)
Tomasello, Bruno; Rossini, Davide; Hamma, Alioscia; Amico, Luigi
2013-06-01
We analyze the quantum discord Q throughout the low temperature phase diagram of the quantum XY model in transverse field. We first focus on the T = 0 order-disorder quantum phase transition QPT both in the symmetric ground state and in the symmetry broken one. Beside it, we highlight how Q displays clear anomalies also at a noncritical value of the control parameter inside the ordered phase, where the ground state is completely factorized. We evidence how the phenomenon is in fact of collective nature and displays universal features. We also study Q at finite temperature. We show that, close to the QPT, Q exhibits quantum-classical crossover of the system with universal scaling behavior. We evidence a nontrivial pattern of thermal correlations resulting from the factorization phenomenon.
Quantum Discord in a Spin System with Symmetry Breaking
NASA Astrophysics Data System (ADS)
Tomasello, Bruno; Rossini, Davide; Hamma, Alioscia; Amico, Luigi
2012-11-01
We analyze the quantum discordQ throughout the low temperature phase diagram of the quantum XY model in transverse field. We first focus on the T = 0 order-disorder quantum phase transition QPT both in the symmetric ground state and in the symmetry broken one. Beside it, we highlight how Q displays clear anomalies also at a noncritical value of the control parameter inside the ordered phase, where the ground state is completely factorized. We evidence how the phenomenon is in fact of collective nature and displays universal features. We also study Q at finite temperature. We show that, close to the QPT, Q exhibits quantum-classical crossover of the system with universal scaling behavior. We evidence a nontrivial pattern of thermal correlations resulting from the factorization phenomenon.
One-norm geometric quantum discord and critical point estimation in the XY spin chain
DOE Office of Scientific and Technical Information (OSTI.GOV)
Cheng, Chang-Cheng; Wang, Yao; Guo, Jin-Liang, E-mail: guojinliang80@163.com
2016-11-15
In contrast with entanglement and quantum discord (QD), we investigate the thermal quantum correlation in terms of Schatten one-norm geometric quantum discord (GQD) in the XY spin chain, and analyze their capabilities in detecting the critical point of quantum phase transition. We show that the one-norm GQD can reveal more properties about quantum correlation between two spins, especially for the long-range quantum correlation at finite temperature. Under the influences of site distance, anisotropy and temperature, one-norm GQD and its first derivative make it possible to detect the critical point efficiently for a general XY spin chain. - Highlights: • Comparingmore » with entanglement and QD, one-norm GQD is more robust versus the temperature. • One-norm GQD is more efficient in characterization of long-range quantum correlation between two distant qubits. • One-norm GQD performs well in highlighting the critical point of QPT at zero or low finite temperature. • One-norm GQD has a number of advantages over QD in detecting the critical point of the spin chain.« less
NASA Astrophysics Data System (ADS)
Castro, E.; Gómez, R.; Ladera, C. L.; Zambrano, A.
2013-11-01
Among many applications quantum weak measurements have been shown to be important in exploring fundamental physics issues, such as the experimental violation of the Heisenberg uncertainty relation and the Hardy paradox, and have also technological implications in quantum optics, quantum metrology and quantum communications, where the precision of the measurement is as important as the precision of quantum state preparation. The theory of weak measurement can be formulated using the pre-and post-selected quantum systems, as well as using the weak measurement operator formalism. In this work, we study the quantum discord (QD) of quasi-Werner mixed states based on bipartite entangled coherent states using the weak measurements operator, instead of the projective measurement operators. We then compare the quantum discord for both kinds of measurement operators, in terms of the entanglement quality, the latter being measured using the concept of concurrence. It's found greater quantum correlations using the weak measurement operators.
NASA Astrophysics Data System (ADS)
Zhang, Ren-jie; Xu, Shuai; Shi, Jia-dong; Ma, Wen-chao; Ye, Liu
2015-11-01
In the paper, we researched the quantum phase transition (QPT) in the anisotropic spin XXZ model by exploiting the quantum renormalization group (QRG) method. The innovation point is that we adopt a new approach called trace distance discord to indicate the quantum correlation of the system. QPT after several iterations of renormalization in current system has been observed. Consequently, it opened the possibility of investigation of QPR in the geometric discord territory. While the anisotropy suppresses the correlation due to favoring of the alignment of spins, the DM interaction restores the spoiled correlation via creation of the quantum fluctuations. We also apply quantum renormalization group method to probe the thermodynamic limit of the model and emerging of nonanalytic behavior of the correlation.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wiseman, Howard M., E-mail: H.Wiseman@Griffith.edu.au
2013-11-15
By rigorously formalizing the Einstein–Podolsky–Rosen (EPR) argument, and Bohr’s reply, one can appreciate that both arguments were technically correct. Their opposed conclusions about the completeness of quantum mechanics hinged upon an explicit difference in their criteria for when a measurement on Alice’s system can be regarded as not disturbing Bob’s system. The EPR criteria allow their conclusion–incompleteness–to be reached by establishing the physical reality of just a single observable q (not of both q and its conjugate observable p), but I show that Bohr’s definition of disturbance prevents the EPR chain of reasoning from establishing even this. Moreover, I showmore » that Bohr’s definition is intimately related to the asymmetric concept of quantum discord from quantum information theory: if and only if the joint state has no Alice-discord, she can measure any observable without disturbing (in Bohr’s sense) Bob’s system. Discord can be present even when systems are unentangled, and this has implications for our understanding of the historical development of notions of quantum nonlocality. -- Highlights: •Both the EPR argument, and Bohr’s reply, were technically correct. •Their opposed conclusions came from different criteria for disturbance. •Bohr’s criterion works against even the simplified (one-variable) EPR argument. •Bohr’s criterion for disturbance is intimately related to quantum discord. •This illuminates the historical development of notions of quantum nonlocality.« less
NASA Astrophysics Data System (ADS)
Slaoui, A.; Daoud, M.; Laamara, R. Ahl
2018-07-01
We employ the concepts of local quantum uncertainty and geometric quantum discord based on the trace norm to investigate the environmental effects on quantum correlations of two bipartite quantum systems. The first one concerns a two-qubit system coupled with two independent bosonic reservoirs. We show that the trace discord exhibits frozen phenomenon contrarily to local quantum uncertainty. The second scenario deals with a two-level system, initially prepared in a separable state, interacting with a quantized electromagnetic radiation. Our results show that there exists an exchange of quantum correlations between the two-level system and its surrounding which is responsible for the revival phenomenon of non-classical correlations.
Multipartite distribution property of one way discord beyond measurement
NASA Astrophysics Data System (ADS)
Liu, Si-Yuan; Zhang, Yu-Ran; Yang, Wen-Li; Fan, Heng
2015-03-01
We investigate the distribution property of one way discord in the multipartite system by introducing the concept of polygamy deficit for one way discord. The difference between one way discord and quantum discord is analogue to the one between entanglement of assistance and entanglement of formation. For tripartite pure states, two kinds of polygamy deficits are presented with the equivalent expressions and physical interpretations regardless of measurement. For four-partite pure states, we provide a condition which makes one way discord polygamy satisfied. In addition, we generalize these results to the case for N-partite pure states. Those results can be applicable to multipartite quantum systems and are complementary to our understanding of the shareability of quantum correlations.
Entanglement as minimal discord over state extensions
NASA Astrophysics Data System (ADS)
Luo, Shunlong
2016-09-01
The characterization and quantification of quantum correlations, which play an instrumental role in exploring and exploiting the quantum world, have been extensively and intensively studied in the past few decades. Of special prominence and significance are the concepts of entanglement and discord, which are usually regarded as very distinctive quantum correlations, with the latter going beyond the former. In this work we establish a direct and natural link between entanglement and discord via state extensions and reveal that entanglement is actually the intrinsic discord, by which we mean that entanglement is the irreducible residue of discord viewed from ambient spaces. Our approach, taking into account the contextuality of a quantum state and being of a global nature, stands in sharp contrast to the local operations and classical communication paradigm of entanglement, which focuses on the state itself via a local approach. Furthermore, we introduce a figure of merit which, on the one hand, captures the essence of entanglement, i.e., nonlocality and quantumness of correlations, and, on the other hand, leads to a quantitative decomposition of total correlations into classical correlations, dissonance, and entanglement. This demystifies the meaning of entanglement from the perspective of quantum measurements and provides a unified framework for the interplay of various correlations in terms of quantum measurements and mutual information.
Operational meaning of discord in terms of teleportation fidelity
NASA Astrophysics Data System (ADS)
Adhikari, Satyabrata; Banerjee, Subhashish
2012-12-01
Quantum discord is a prominent measure of quantum correlations, playing an important role in expanding its horizon beyond entanglement. Here we provide an operational meaning of (geometric) discord, which quantifies the amount of nonclassical correlations of an arbitrary quantum system based on its minimal distance from the set of classical states, in terms of teleportation fidelity for general two-qubit and (d⊗d)-dimensional isotropic and Werner states. A critical value of the discord is found beyond which the two-qubit state must violate Bell's inequality. This is illustrated by an open-system model of a dissipative two-qubit state. For the (d⊗d)-dimensional states the lower bound of discord is shown to be obtainable from an experimentally measurable witness operator.
Generation of a non-zero discord bipartite state with classical second-order interference.
Choi, Yujun; Hong, Kang-Hee; Lim, Hyang-Tag; Yune, Jiwon; Kwon, Osung; Han, Sang-Wook; Oh, Kyunghwan; Kim, Yoon-Ho; Kim, Yong-Su; Moon, Sung
2017-02-06
We report an investigation on quantum discord in classical second-order interference. In particular, we theoretically show that a bipartite state with D = 0.311 of discord can be generated via classical second-order interference. We also experimentally verify the theory by obtaining D = 0.197 ± 0.060 of non-zero discord state. Together with the fact that the nonclassicalities originated from physical constraints and information theoretic perspectives are not equivalent, this result provides an insight to understand the nature of quantum discord.
Time-invariant discord: high temperature limit and initial environmental correlations
NASA Astrophysics Data System (ADS)
Tabesh, F. T.; Karpat, G.; Maniscalco, S.; Salimi, S.; Khorashad, A. S.
2018-04-01
We present a thorough investigation of the phenomena of frozen and time-invariant quantum discord for two-qubit systems independently interacting with local reservoirs. Our work takes into account several significant effects present in decoherence models, which have not been yet explored in the context of time-invariant quantum discord, but which in fact must be typically considered in almost all realistic models. Firstly, we study the combined influence of dephasing, dissipation and heating reservoirs at finite temperature. Contrarily to previous claims in the literature, we show the existence of time-invariant discord at high temperature limit in the weak coupling regime and also examine the effect of thermal photons on the dynamical behavior of frozen discord. Secondly, we explore the consequences of having initial correlations between the dephasing reservoirs. We demonstrate in detail how the time-invariant discord is modified depending on the relevant system parameters such as the strength of the initial amount of entanglement between the reservoirs.
Quantum coherence and correlations in quantum system
Xi, Zhengjun; Li, Yongming; Fan, Heng
2015-01-01
Criteria of measure quantifying quantum coherence, a unique property of quantum system, are proposed recently. In this paper, we first give an uncertainty-like expression relating the coherence and the entropy of quantum system. This finding allows us to discuss the relations between the entanglement and the coherence. Further, we discuss in detail the relations among the coherence, the discord and the deficit in the bipartite quantum system. We show that, the one-way quantum deficit is equal to the sum between quantum discord and the relative entropy of coherence of measured subsystem. PMID:26094795
Rényi squashed entanglement, discord, and relative entropy differences
NASA Astrophysics Data System (ADS)
Seshadreesan, Kaushik P.; Berta, Mario; Wilde, Mark M.
2015-10-01
The squashed entanglement quantifies the amount of entanglement in a bipartite quantum state, and it satisfies all of the axioms desired for an entanglement measure. The quantum discord is a measure of quantum correlations that are different from those due to entanglement. What these two measures have in common is that they are both based upon the conditional quantum mutual information. In Berta et al (2015 J. Math. Phys. 56 022205), we recently proposed Rényi generalizations of the conditional quantum mutual information of a tripartite state on ABC (with C being the conditioning system), which were shown to satisfy some properties that hold for the original quantity, such as non-negativity, duality, and monotonicity with respect to local operations on the system B (with it being left open to show that the Rényi quantity is monotone with respect to local operations on system A). Here we define a Rényi squashed entanglement and a Rényi quantum discord based on a Rényi conditional quantum mutual information and investigate these quantities in detail. Taking as a conjecture that the Rényi conditional quantum mutual information is monotone with respect to local operations on both systems A and B, we prove that the Rényi squashed entanglement and the Rényi quantum discord satisfy many of the properties of the respective original von Neumann entropy based quantities. In our prior work (Berta et al 2015 Phys. Rev. A 91 022333), we also detailed a procedure to obtain Rényi generalizations of any quantum information measure that is equal to a linear combination of von Neumann entropies with coefficients chosen from the set \\{-1,0,1\\}. Here, we extend this procedure to include differences of relative entropies. Using the extended procedure and a conjectured monotonicity of the Rényi generalizations in the Rényi parameter, we discuss potential remainder terms for well known inequalities such as monotonicity of the relative entropy, joint convexity of the relative
Gaussian geometric discord in terms of Hellinger distance
DOE Office of Scientific and Technical Information (OSTI.GOV)
Suciu, Serban, E-mail: serban.suciu@theory.nipne.ro; Isar, Aurelian
2015-12-07
In the framework of the theory of open systems based on completely positive quantum dynamical semigroups, we address the quantification of general non-classical correlations in Gaussian states of continuous variable systems from a geometric perspective. We give a description of the Gaussian geometric discord by using the Hellinger distance as a measure for quantum correlations between two non-interacting non-resonant bosonic modes embedded in a thermal environment. We evaluate the Gaussian geometric discord by taking two-mode squeezed thermal states as initial states of the system and show that it has finite values between 0 and 1 and that it decays asymptoticallymore » to zero in time under the effect of the thermal bath.« less
Quantum correlations in multipartite quantum systems
NASA Astrophysics Data System (ADS)
Jafarizadeh, M. A.; Heshmati, A.; Karimi, N.; Yahyavi, M.
2018-03-01
Quantum entanglement is the most famous type of quantum correlation between elements of a quantum system that has a basic role in quantum communication protocols like quantum cryptography, teleportation and Bell inequality detection. However, it has already been shown that various applications in quantum information theory do not require entanglement. Quantum discord as a new kind of quantum correlations beyond entanglement, is the most popular candidate for general quantum correlations. In this paper, first we find the entanglement witness in a particular multipartite quantum system which consists of a N-partite system in 2 n -dimensional space. Then we give an exact analytical formula for the quantum discord of this system. At the end of the paper, we investigate the additivity relation of the quantum correlation and show that this relation is satisfied for a N-partite system with 2 n -dimensional space.
Symmetry restoration and quantumness reestablishment.
Zeng, Guo-Mo; Wu, Lian-Ao; Xing, Hai-Jun
2014-09-18
A realistic quantum many-body system, characterized by a generic microscopic Hamiltonian, is accessible only through approximation methods. The mean field theories, as the simplest practices of approximation methods, commonly serve as a powerful tool, but unfortunately often violate the symmetry of the Hamiltonian. The conventional BCS theory, as an excellent mean field approach, violates the particle number conservation and completely erases quantumness characterized by concurrence and quantum discord between different modes. We restore the symmetry by using the projected BCS theory and the exact numerical solution and find that the lost quantumness is synchronously reestablished. We show that while entanglement remains unchanged with the particle numbers, quantum discord behaves as an extensive quantity with respect to the system size. Surprisingly, discord is hardly dependent on the interaction strengths. The new feature of discord offers promising applications in modern quantum technologies.
From quantum coherence to quantum correlations
NASA Astrophysics Data System (ADS)
Sun, Yuan; Mao, Yuanyuan; Luo, Shunlong
2017-06-01
In quantum mechanics, quantum coherence of a state relative to a quantum measurement can be identified with the quantumness that has to be destroyed by the measurement. In particular, quantum coherence of a bipartite state relative to a local quantum measurement encodes quantum correlations in the state. If one takes minimization with respect to the local measurements, then one is led to quantifiers which capture quantum correlations from the perspective of coherence. In this vein, quantum discord, which quantifies the minimal correlations that have to be destroyed by quantum measurements, can be identified as the minimal coherence, with the coherence measured by the relative entropy of coherence. To advocate and formulate this idea in a general context, we first review coherence relative to Lüders measurements which extends the notion of coherence relative to von Neumann measurements (or equivalently, orthonomal bases), and highlight the observation that quantum discord arises as minimal coherence through two prototypical examples. Then, we introduce some novel measures of quantum correlations in terms of coherence, illustrate them through examples, investigate their fundamental properties and implications, and indicate their applications to quantum metrology.
Super-quantum correlation for SU(2) invariant state in 4⊗ 2 system
NASA Astrophysics Data System (ADS)
Li, Lin-Song; Tao, Yuan-Hong; Nan, Hua; Xu, Hui
2018-04-01
We analytically evaluate the weak one-way deficit and super-quantum discord for a system composed of spin-3/2 and spin-1/2 subsystems possessing SU(2) symmetry. We also make a comparative study of the relationships among the quantum discord, one-way deficit, weak one-way deficit, and super-quantum discord for the SU(2) invariant state. It is shown that super-quantum discord via weak measurement is greater than that via von Neumann measurement. But weak one-way deficit is less than the one-way deficit. As a result, weak measurement do not always reveal more quantumness.
Multiparty quantum mutual information: An alternative definition
NASA Astrophysics Data System (ADS)
Kumar, Asutosh
2017-07-01
Mutual information is the reciprocal information that is common to or shared by two or more parties. Quantum mutual information for bipartite quantum systems is non-negative, and bears the interpretation of total correlation between the two subsystems. This may, however, no longer be true for three or more party quantum systems. In this paper, we propose an alternative definition of multipartite information, taking into account the shared information between two and more parties. It is non-negative, observes monotonicity under partial trace as well as completely positive maps, and equals the multipartite information measure in literature for pure states. We then define multiparty quantum discord, and give some examples. Interestingly, we observe that quantum discord increases when a measurement is performed on a large number of subsystems. Consequently, the symmetric quantum discord, which involves a measurement on all parties, reveals the maximal quantumness. This raises a question on the interpretation of measured mutual information as a classical correlation.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Harsij, Zeynab, E-mail: z.harsij@ph.iut.ac.ir; Mirza, Behrouz, E-mail: b.mirza@cc.iut.ac.ir
A helicity entangled tripartite state is considered in which the degree of entanglement is preserved in non-inertial frames. It is shown that Quantum Entanglement remains observer independent. As another measure of quantum correlation, Quantum Discord has been investigated. It is explicitly shown that acceleration has no effect on the degree of quantum correlation for the bipartite and tripartite helicity entangled states. Geometric Quantum Discord as a Hilbert–Schmidt distance is computed for helicity entangled states. It is shown that living in non-inertial frames does not make any influence on this distance, either. In addition, the analysis has been extended beyond singlemore » mode approximation to show that acceleration does not have any impact on the quantum features in the limit beyond the single mode. As an interesting result, while the density matrix depends on the right and left Unruh modes, the Negativity as a measure of Quantum Entanglement remains constant. Also, Quantum Discord does not change beyond single mode approximation. - Highlights: • The helicity entangled states here are observer independent in non-inertial frames. • It is explicitly shown that Quantum Discord for these states is observer independent. • Geometric Quantum Discord is also not affected by acceleration increase. • Extending to beyond single mode does not change the degree of entanglement. • Beyond single mode approximation the degree of Quantum Discord is also preserved.« less
Relating quantum coherence and correlations with entropy-based measures.
Wang, Xiao-Li; Yue, Qiu-Ling; Yu, Chao-Hua; Gao, Fei; Qin, Su-Juan
2017-09-21
Quantum coherence and quantum correlations are important quantum resources for quantum computation and quantum information. In this paper, using entropy-based measures, we investigate the relationships between quantum correlated coherence, which is the coherence between subsystems, and two main kinds of quantum correlations as defined by quantum discord as well as quantum entanglement. In particular, we show that quantum discord and quantum entanglement can be well characterized by quantum correlated coherence. Moreover, we prove that the entanglement measure formulated by quantum correlated coherence is lower and upper bounded by the relative entropy of entanglement and the entanglement of formation, respectively, and equal to the relative entropy of entanglement for all the maximally correlated states.
Probing the non-locality of Majorana fermions via quantum correlations
Li, Jun; Yu, Ting; Lin, Hai-Qing; You, J. Q.
2014-01-01
Majorana fermions (MFs) are exotic particles that are their own anti-particles. Recently, the search for the MFs occurring as quasi-particle excitations in solid-state systems has attracted widespread interest, because of their fundamental importance in fundamental physics and potential applications in topological quantum computation based on solid-state devices. Here we study the quantum correlations between two spatially separate quantum dots induced by a pair of MFs emerging at the two ends of a semiconductor nanowire, in order to develop a new method for probing the MFs. We find that without the tunnel coupling between these paired MFs, quantum entanglement cannot be induced from an unentangled (i.e., product) state, but quantum discord is observed due to the intrinsic nonlocal correlations of the paired MFs. This finding reveals that quantum discord can indeed demonstrate the intrinsic non-locality of the MFs formed in the nanowire. Also, quantum discord can be employed to discriminate the MFs from the regular fermions. Furthermore, we propose an experimental setup to measure the onset of quantum discord due to the nonlocal correlations. Our approach provides a new, and experimentally accessible, method to study the Majorana bound states by probing their intrinsic non-locality signature. PMID:24816484
Non-classical Correlations and Quantum Coherence in Mixed Environments
NASA Astrophysics Data System (ADS)
Hu, Zheng-Da; Wei, Mei-Song; Wang, Jicheng; Zhang, Yixin; He, Qi-Liang
2018-05-01
We investigate non-classical correlations (entanglement and quantum discord) and quantum coherence for an open two-qubit system each independently coupled to a bosonic environment and a spin environment, respectively. The modulating effects of spin environment and bosonic environment are respectively explored. A relation among the quantum coherence, quantum discord and classical correlation is found during the sudden transition phenomenon. We also compare the case of mixed environments with that of the same environments, showing that the dynamics is dramatically changed.
Experimental quantum computing without entanglement.
Lanyon, B P; Barbieri, M; Almeida, M P; White, A G
2008-11-14
Deterministic quantum computation with one pure qubit (DQC1) is an efficient model of computation that uses highly mixed states. Unlike pure-state models, its power is not derived from the generation of a large amount of entanglement. Instead it has been proposed that other nonclassical correlations are responsible for the computational speedup, and that these can be captured by the quantum discord. In this Letter we implement DQC1 in an all-optical architecture, and experimentally observe the generated correlations. We find no entanglement, but large amounts of quantum discord-except in three cases where an efficient classical simulation is always possible. Our results show that even fully separable, highly mixed, states can contain intrinsically quantum mechanical correlations and that these could offer a valuable resource for quantum information technologies.
NASA Astrophysics Data System (ADS)
Xie, Chuan-Mei; Liu, Yi-Min; Xing, Hang; Zhang, Zhan-Jun
2015-04-01
Quantum correlations in a family of states comprising any mixture of a pair of arbitrary bi-qubit product pure states are studied by employing geometric discord [Phys. Rev. Lett. 105 (2010) 190502] as the quantifier. First, the inherent symmetry in the family of states about local unitary transformations is revealed. Then, the analytic expression of geometric discords in the states is worked out. Some concrete discussions and analyses on the captured geometric discords are made so that their distinct features are exposed. It is found that, the more averagely the two bi-qubit product states are mixed, the bigger geometric discord the mixed state owns. Moreover, the monotonic relationships of geometric discord with different parameters are revealed. Supported by the National Natural Science Foundation of China (NNSFC) under Grant Nos. 11375011 and 11372122, the Natural Science Foundation of Anhui Province under Grant No. 1408085MA12, and the 211 Project of Anhui University
Signatures of bifurcation on quantum correlations: Case of the quantum kicked top
NASA Astrophysics Data System (ADS)
Bhosale, Udaysinh T.; Santhanam, M. S.
2017-01-01
Quantum correlations reflect the quantumness of a system and are useful resources for quantum information and computational processes. Measures of quantum correlations do not have a classical analog and yet are influenced by classical dynamics. In this work, by modeling the quantum kicked top as a multiqubit system, the effect of classical bifurcations on measures of quantum correlations such as the quantum discord, geometric discord, and Meyer and Wallach Q measure is studied. The quantum correlation measures change rapidly in the vicinity of a classical bifurcation point. If the classical system is largely chaotic, time averages of the correlation measures are in good agreement with the values obtained by considering the appropriate random matrix ensembles. The quantum correlations scale with the total spin of the system, representing its semiclassical limit. In the vicinity of trivial fixed points of the kicked top, the scaling function decays as a power law. In the chaotic limit, for large total spin, quantum correlations saturate to a constant, which we obtain analytically, based on random matrix theory, for the Q measure. We also suggest that it can have experimental consequences.
Some New Properties of Quantum Correlations
NASA Astrophysics Data System (ADS)
Liu, Feng; Li, Fei; Wei, Yunxia
2017-02-01
Quantum coherence measures the correlation between different measurement results in a single-system, while entanglement and quantum discord measure the correlation among different subsystems in a multipartite system. In this paper, we focus on the relative entropy form of them, and obtain three new properties of them as follows: 1) General forms of maximally coherent states for the relative entropy coherence, 2) Linear monogamy of the relative entropy entanglement, and 3) Subadditivity of quantum discord. Here, the linear monogamy is defined as there is a small constant as the upper bound on the sum of the relative entropy entanglement in subsystems.
Dynamics and protection of tripartite quantum correlations in a thermal bath
DOE Office of Scientific and Technical Information (OSTI.GOV)
Guo, Jin-Liang, E-mail: guojinliang80@163.com; Wei, Jin-Long
2015-03-15
We study the dynamics and protection of tripartite quantum correlations in terms of genuinely tripartite concurrence, lower bound of concurrence and tripartite geometric quantum discord in a three-qubit system interacting with independent thermal bath. By comparing the dynamics of entanglement with that of quantum discord for initial GHZ state and W state, we find that W state is more robust than GHZ state, and quantum discord performs better than entanglement against the decoherence induced by the thermal bath. When the bath temperature is low, for the initial GHZ state, combining weak measurement and measurement reversal is necessary for a successfulmore » protection of quantum correlations. But for the initial W state, the protection depends solely upon the measurement reversal. In addition, the protection cannot usually be realized irrespective of the initial states as the bath temperature increases.« less
Two-qubit quantum cloning machine and quantum correlation broadcasting
NASA Astrophysics Data System (ADS)
Kheirollahi, Azam; Mohammadi, Hamidreza; Akhtarshenas, Seyed Javad
2016-11-01
Due to the axioms of quantum mechanics, perfect cloning of an unknown quantum state is impossible. But since imperfect cloning is still possible, a question arises: "Is there an optimal quantum cloning machine?" Buzek and Hillery answered this question and constructed their famous B-H quantum cloning machine. The B-H machine clones the state of an arbitrary single qubit in an optimal manner and hence it is universal. Generalizing this machine for a two-qubit system is straightforward, but during this procedure, except for product states, this machine loses its universality and becomes a state-dependent cloning machine. In this paper, we propose some classes of optimal universal local quantum state cloners for a particular class of two-qubit systems, more precisely, for a class of states with known Schmidt basis. We then extend our machine to the case that the Schmidt basis of the input state is deviated from the local computational basis of the machine. We show that more local quantum coherence existing in the input state corresponds to less fidelity between the input and output states. Also we present two classes of a state-dependent local quantum copying machine. Furthermore, we investigate local broadcasting of two aspects of quantum correlations, i.e., quantum entanglement and quantum discord, defined, respectively, within the entanglement-separability paradigm and from an information-theoretic perspective. The results show that although quantum correlation is, in general, very fragile during the broadcasting procedure, quantum discord is broadcasted more robustly than quantum entanglement.
Multipartite quantum correlations and local recoverability
Wilde, Mark M.
2015-01-01
Characterizing genuine multipartite quantum correlations in quantum physical systems has historically been a challenging problem in quantum information theory. More recently, however, the total correlation or multipartite information measure has been helpful in accomplishing this goal, especially with the multipartite symmetric quantum (MSQ) discord (Piani et al. 2008 Phys. Rev. Lett. 100, 090502. (doi:10.1103/PhysRevLett.100.090502)) and the conditional entanglement of multipartite information (CEMI) (Yang et al. 2008 Phys. Rev. Lett. 101, 140501. (doi:10.1103/PhysRevLett.101.140501)). Here, we apply a recent and significant improvement of strong subadditivity of quantum entropy (Fawzi & Renner 2014 (http://arxiv.org/abs/1410.0664)) in order to develop these quantities further. In particular, we prove that the MSQ discord is nearly equal to zero if and only if the multipartite state for which it is evaluated is approximately locally recoverable after performing measurements on each of its systems. Furthermore, we prove that the CEMI is a faithful entanglement measure, i.e. it vanishes if and only if the multipartite state for which it is evaluated is a fully separable state. Along the way, we provide an operational interpretation of the MSQ discord in terms of the partial state distribution protocol, which in turn, as a special case, gives an interpretation for the original discord quantity. Finally, we prove an inequality that could potentially improve upon the Fawzi–Renner inequality in the multipartite context, but it remains an open question to determine whether this is so. PMID:27547097
NASA Astrophysics Data System (ADS)
Harsij, Zeynab; Mirza, Behrouz
2014-12-01
A helicity entangled tripartite state is considered in which the degree of entanglement is preserved in non-inertial frames. It is shown that Quantum Entanglement remains observer independent. As another measure of quantum correlation, Quantum Discord has been investigated. It is explicitly shown that acceleration has no effect on the degree of quantum correlation for the bipartite and tripartite helicity entangled states. Geometric Quantum Discord as a Hilbert-Schmidt distance is computed for helicity entangled states. It is shown that living in non-inertial frames does not make any influence on this distance, either. In addition, the analysis has been extended beyond single mode approximation to show that acceleration does not have any impact on the quantum features in the limit beyond the single mode. As an interesting result, while the density matrix depends on the right and left Unruh modes, the Negativity as a measure of Quantum Entanglement remains constant. Also, Quantum Discord does not change beyond single mode approximation.
Faithful nonclassicality indicators and extremal quantum correlations in two-qubit states
NASA Astrophysics Data System (ADS)
Girolami, Davide; Paternostro, Mauro; Adesso, Gerardo
2011-09-01
The state disturbance induced by locally measuring a quantum system yields a signature of nonclassical correlations beyond entanglement. Here, we present a detailed study of such correlations for two-qubit mixed states. To overcome the asymmetry of quantum discord and the unfaithfulness of measurement-induced disturbance (severely overestimating quantum correlations), we propose an ameliorated measurement-induced disturbance as nonclassicality indicator, optimized over joint local measurements, and we derive its closed expression for relevant two-qubit states. We study its analytical relation with discord, and characterize the maximally quantum-correlated mixed states, that simultaneously extremize both quantifiers at given von Neumann entropy: among all two-qubit states, these states possess the most robust quantum correlations against noise.
Qubit assisted enhancement of quantum correlations in an optomechanical system
NASA Astrophysics Data System (ADS)
Chakraborty, Subhadeep; Sarma, Amarendra K.
2018-05-01
We perform a theoretical study on quantum correlations in an optomechanical system where the mechanical mirror is perturbatively coupled to an auxiliary qubit. In our study, we consider logarithmic negativity to quantify the degree of stationary entanglement between the cavity field and mechanical mirror, and, Gaussian quantum discord as a witness of the quantumness of the correlation beyond entanglement. Utilizing experimentally feasible parameters, we show that both entanglement and quantum discord enhance significantly with increase in mirror-qubit coupling. Moreover, we find that in presence of the mirror-qubit coupling entanglement could be generated at a considerably lower optomechanical coupling strength, which is also extremely robust against the environmental temperature. Overall, our proposed scheme offers some considerable advantages for realizing the continuous-variable quantum information and communication.
Sequential state discrimination and requirement of quantum dissonance
NASA Astrophysics Data System (ADS)
Pang, Chao-Qian; Zhang, Fu-Lin; Xu, Li-Fang; Liang, Mai-Lin; Chen, Jing-Ling
2013-11-01
We study the procedure for sequential unambiguous state discrimination. A qubit is prepared in one of two possible states and measured by two observers Bob and Charlie sequentially. A necessary condition for the state to be unambiguously discriminated by Charlie is the absence of entanglement between the principal qubit, prepared by Alice, and Bob's auxiliary system. In general, the procedure for both Bob and Charlie to recognize between two nonorthogonal states conclusively relies on the availability of quantum discord which is precisely the quantum dissonance when the entanglement is absent. In Bob's measurement, the left discord is positively correlated with the information extracted by Bob, and the right discord enhances the information left to Charlie. When their product achieves its maximum the probability for both Bob and Charlie to identify the state achieves its optimal value.
Conclusive identification of quantum channels via monogamy of quantum correlations
NASA Astrophysics Data System (ADS)
Kumar, Asutosh; Singha Roy, Sudipto; Pal, Amit Kumar; Prabhu, R.; Sen(De), Aditi; Sen, Ujjwal
2016-10-01
We investigate the action of global noise and local channels, namely, amplitude-damping, phase-damping, and depolarizing channels, on monogamy of quantum correlations, such as negativity and quantum discord, in three-qubit systems. We discuss the monotonic and non-monotonic variation, and robustness of the monogamy scores. By using monogamy scores, we propose a two-step protocol to conclusively identify the noise applied to the quantum system, by using generalized Greenberger-Horne-Zeilinger and generalized W states as resource states. We discuss a possible generalization of the results to higher number of parties.
Strong polygamy of quantum correlations in multi-party quantum systems
NASA Astrophysics Data System (ADS)
Kim, Jeong San
2014-10-01
We propose a new type of polygamy inequality for multi-party quantum entanglement. We first consider the possible amount of bipartite entanglement distributed between a fixed party and any subset of the rest parties in a multi-party quantum system. By using the summation of these distributed entanglements, we provide an upper bound of the distributed entanglement between a party and the rest in multi-party quantum systems. We then show that this upper bound also plays as a lower bound of the usual polygamy inequality, therefore the strong polygamy of multi-party quantum entanglement. For the case of multi-party pure states, we further show that the strong polygamy of entanglement implies the strong polygamy of quantum discord.
NASA Astrophysics Data System (ADS)
Roszak, Katarzyna; Cywiński, Łukasz
2018-01-01
We find that when a qubit initialized in a pure state experiences pure dephasing due to interaction with an environment, separable qubit-environment states generated during the evolution also have zero quantum discord with respect to the environment. What follows is that the set of separable states which can be reached during the evolution has zero volume, and hence, such effects as sudden death of qubit-environment entanglement are very unlikely. In the case of the discord with respect to the qubit, a vast majority of qubit-environment separable states is discordant, but in specific situations zero-discord states are possible. This is conceptually important since there is a connection between the discordance with respect to a given subsystem and the possibility of describing the evolution of this subsystem using completely positive maps. Finally, we use the formalism to find an exemplary evolution of an entangled state of two qubits that is completely positive, and occurs solely due to interaction of only one of the qubits with its environment (so one could guess that it corresponds to a local operation, since it is local in a physical sense), but which nevertheless causes the enhancement of entanglement between the qubits. While this simply means that the considered evolution is completely positive, but does not belong to local operations and classical communication, it shows how much caution has to be exercised when identifying evolution channels that belong to that class.
Quantum coherence behaviors of fermionic system in non-inertial frame
NASA Astrophysics Data System (ADS)
Huang, Zhiming; Situ, Haozhen
2018-04-01
In this paper, we analyze the quantum coherence behaviors of a single qubit in the relativistic regime beyond the single-mode approximation. Firstly, we investigate the freezing condition of quantum coherence in fermionic system. We also study the quantum coherence tradeoff between particle and antiparticle sector. It is found that there exists quantum coherence transfer between particle and antiparticle sector, but the coherence lost in particle sector is not entirely compensated by the coherence generation of antiparticle sector. Besides, we emphatically discuss the cohering power and decohering power of Unruh channel with respect to the computational basis. It is shown that cohering power is vanishing and decohering power is dependent of the choice of Unruh mode and acceleration. Finally, we compare the behaviors of quantum coherence with geometric quantum discord and entanglement in relativistic setup. Our results show that this quantifiers in two region converge at infinite acceleration limit, which implies that this measures become independent of Unruh modes beyond the single-mode approximations. It is also demonstrated that the robustness of quantum coherence and geometric quantum discord are better than entanglement under the influence of acceleration, since entanglement undergoes sudden death.
Genuine quantum correlations in quantum many-body systems: a review of recent progress
NASA Astrophysics Data System (ADS)
De Chiara, Gabriele; Sanpera, Anna
2018-07-01
Quantum information theory has considerably helped in the understanding of quantum many-body systems. The role of quantum correlations and in particular, bipartite entanglement, has become crucial to characterise, classify and simulate quantum many body systems. Furthermore, the scaling of entanglement has inspired modifications to numerical techniques for the simulation of many-body systems leading to the, now established, area of tensor networks. However, the notions and methods brought by quantum information do not end with bipartite entanglement. There are other forms of correlations embedded in the ground, excited and thermal states of quantum many-body systems that also need to be explored and might be utilised as potential resources for quantum technologies. The aim of this work is to review the most recent developments regarding correlations in quantum many-body systems focussing on multipartite entanglement, quantum nonlocality, quantum discord, mutual information but also other non classical measures of correlations based on quantum coherence. Moreover, we also discuss applications of quantum metrology in quantum many-body systems.
Problem of quantifying quantum correlations with non-commutative discord
NASA Astrophysics Data System (ADS)
Majtey, A. P.; Bussandri, D. G.; Osán, T. M.; Lamberti, P. W.; Valdés-Hernández, A.
2017-09-01
In this work we analyze a non-commutativity measure of quantum correlations recently proposed by Guo (Sci Rep 6:25241, 2016). By resorting to a systematic survey of a two-qubit system, we detected an undesirable behavior of such a measure related to its representation-dependence. In the case of pure states, this dependence manifests as a non-satisfactory entanglement measure whenever a representation other than the Schmidt's is used. In order to avoid this basis-dependence feature, we argue that a minimization procedure over the set of all possible representations of the quantum state is required. In the case of pure states, this minimization can be analytically performed and the optimal basis turns out to be that of Schmidt's. In addition, the resulting measure inherits the main properties of Guo's measure and, unlike the latter, it reduces to a legitimate entanglement measure in the case of pure states. Some examples involving general mixed states are also analyzed considering such an optimization. The results show that, in most cases of interest, the use of Guo's measure can result in an overestimation of quantum correlations. However, since Guo's measure has the advantage of being easily computable, it might be used as a qualitative estimator of the presence of quantum correlations.
[Birth weight discordance in dichorionic twins: diagnosis, obstetrical and neonatal prognosis].
Mottet, N; Guillaume, M; Martin, A; Ramanah, R; Riethmuller, D
2014-09-01
To describe neonatal and obstetrical prognosis in dichorionic (DC) twins with a birth weight discordance under 20% and evaluate the influence of intrauterine growth restriction on the management. We studied retrospectively 67 DC twins birth between July 2002 and July 2012 at our university labour ward. Birth weight discordance was considered slight between 20-25%, moderate between 25-30%, and severe over 30%. Prevalence of birth weight discordance in DC twins is estimated at 11.4% in our study. Eighty percent of severe discordance was diagnosed before delivery, 41% for moderate discordance and 20% for slight discordance. We note 30% of pre eclampsia in our population with 44% in the severe discordance group. Mean gestational age was 35.1 weeks for slight and moderate discordances, and 33 weeks for severe discordance. Caesarean section rate was 48% for severe discordance and only 36% for slight discordance. Vaginal delivery rate is 56.7%. More than half of patient with a severe discordance gave birth vaginally. Intrauterine growth restriction rate under the 10th percentile was 18.7%. Prevalence of IUGR was 24% in sever discordance group, 23.5% in the moderate discordance group and 10% in the slight group. Neonatal morbidity rate was 20.8% mainly in children with IUGR. Neonatal mortality and morbidity rate are mainly increased in severe discordant twins. These pregnancies are at high risk of maternal morbidity. Vaginal delivery must be preferred for slight and moderate discordances. In case of severe discordance, vaginal delivery should be considered depending on the degree of intrauterine growth retardation. Copyright © 2014 Elsevier Masson SAS. All rights reserved.
Quantum Correlation Properties in Composite Parity-Conserved Matrix Product States
NASA Astrophysics Data System (ADS)
Zhu, Jing-Min
2016-09-01
We give a new thought for constructing long-range quantum correlation in quantum many-body systems. Our proposed composite parity-conserved matrix product state has long-range quantum correlation only for two spin blocks where their spin-block length larger than 1 compared to any subsystem only having short-range quantum correlation, and we investigate quantum correlation properties of two spin blocks varying with environment parameter and spacing spin number. We also find that the geometry quantum discords of two nearest-neighbor spin blocks and two next-nearest-neighbor spin blocks become smaller and for other conditions the geometry quantum discord becomes larger than that in any subcomponent, i.e., the increase or the production of the long-range quantum correlation is at the cost of reducing the short-range quantum correlation compared to the corresponding classical correlation and total correlation having no any characteristic of regulation. For nearest-neighbor and next-nearest-neighbor all the correlations take their maximal values at the same points, while for other conditions no whether for spacing same spin number or for different spacing spin numbers all the correlations taking their maximal values are respectively at different points which are very close. We believe that our work is helpful to comprehensively and deeply understand the organization and structure of quantum correlation especially for long-range quantum correlation of quantum many-body systems; and further helpful for the classification, the depiction and the measure of quantum correlation of quantum many-body systems.
Characterizing nonclassical correlations via local quantum Fisher information
NASA Astrophysics Data System (ADS)
Kim, Sunho; Li, Longsuo; Kumar, Asutosh; Wu, Junde
2018-03-01
We define two ways of quantifying the quantum correlations based on quantum Fisher information (QFI) in order to study the quantum correlations as a resource in quantum metrology. By investigating the hierarchy of measurement-induced Fisher information introduced in Lu et al. [X. M. Lu, S. Luo, and C. H. Oh, Phys. Rev. A 86, 022342 (2012), 10.1103/PhysRevA.86.022342], we show that the presence of quantum correlation can be confirmed by the difference of the Fisher information induced by the measurements of two hierarchies. In particular, the quantitative quantum correlations based on QFI coincide with the geometric discord for pure quantum states.
Genuine quantum correlations in quantum many-body systems: a review of recent progress.
De Chiara, Gabriele; Sanpera, Anna
2018-04-19
Quantum information theory has considerably helped in the understanding of quantum many-body systems. The role of quantum correlations and in particular, bipartite entanglement, has become crucial to characterise, classify and simulate quantum many body systems. Furthermore, the scaling of entanglement has inspired modifications to numerical techniques for the simulation of many-body systems leading to the, now established, area of tensor networks. However, the notions and methods brought by quantum information do not end with bipartite entanglement. There are other forms of correlations embedded in the ground, excited and thermal states of quantum many-body systems that also need to be explored and might be utilised as potential resources for quantum technologies. The aim of this work is to review the most recent developments regarding correlations in quantum many-body systems focussing on multipartite entanglement, quantum nonlocality, quantum discord, mutual information but also other non classical measures of correlations based on quantum coherence. Moreover, we also discuss applications of quantum metrology in quantum many-body systems. © 2018 IOP Publishing Ltd.
Parental Marital Discord and Treatment Response in Depressed Adolescents
ERIC Educational Resources Information Center
Amaya, Meredith M.; Reinecke, Mark A.; Silva, Susan G.; March, John S.
2011-01-01
Evidence suggests that parental marital discord contributes to the development of internalizing and externalizing symptoms in children and adolescents. Few studies, however, have examined the association between parental marital discord and youth's response to treatment. The present study examined the impact of interparental discord on treatment…
Sexual Orientation Discordance and Young Adult Mental Health.
Lourie, Michael A; Needham, Belinda L
2017-05-01
During the course of sexual development, many people experience dissonance between dimensions of sexual orientation, including attraction, behavior, and identity. This study assesses the relationship between sexual orientation discordance and mental health. Data were obtained from the National Longitudinal Study of Adolescent to Adult Health (n = 8,915; female = 54.62 %; non-Hispanic black = 18.83 %, Hispanic = 14.91 %, other race (non-white) = 10.79 %). Multivariable linear regression evaluated the correlation between sexual orientation discordance and perceived stress and depressive symptomatology. Models were stratified by sex and sexual identity. Among self-identified heterosexual females and mostly heterosexual males, sexual orientation discordance predicted significantly increased depressive symptomatology. No other subpopulation demonstrated a significant correlation between sexual orientation discordance and depressive symptomatology or perceived stress. The association between sexual orientation discordance and depressive symptomatology suggests a link between sexuality, self-concept, and mental health.
NASA Astrophysics Data System (ADS)
Mohamed, Abdel-Baset A.
2018-04-01
In this paper, some non-classical correlations are investigated for bipartite partitions of two qubits trapped in two spatially separated cavities connected by an optical fiber. The results show that the trace distance discord and Bell's non-locality introduce other quantum correlations beyond the entanglement. Moreover, the correlation functions of the trace distance discord and the Bell's non-locality are very sensitive to the initial correlations, the coupling strengths, and the dissipation rates of the cavities. The fluctuations of the correlation functions between their initial values and gained (loss) values appear due to the unitary evolution of the system. These fluctuations depend on the chosen initial correlations between the two subsystems. The maximal violations of Bell's inequality occur when the logarithmic negativity and the trace distance discord reach certain values. It is shown that the robustness of the non-classical correlations, against the dissipation rates of the cavities, depends on the bipartite partitions reduced density matrices of the system, and is also greatly enhanced by choosing appropriate coupling strengths.
Oxygen isotopic composition and U-Pb discordance in zircon
Booth, A.L.; Kolodny, Y.; Chamberlain, C.P.; McWilliams, M.; Schmitt, A.K.; Wooden, J.
2005-01-01
We have investigated U-Pb discordance and oxygen isotopic composition of zircon using high-spatial resolution ??18O measurement by ion microprobe. ??18O in both concordant and discordant zircon grains provides an indication of the relationship between fluid interaction and discordance. Our results suggest that three characteristics of zircon are interrelated: (1) U-Pb systematics and concomitant age discordance, (2) ??18O and the water-rock interactions implied therein, and (3) zircon texture, as revealed by cathodoluminescence and BSE imaging. A key observation is that U-Pb-disturbed zircons are often also variably depleted in 18O, but the relationship between discordance and ??18O is not systematic. ??18O values of discordant zircons are generally lighter but irregular in their distribution. Textural differences between zircon grains can be correlated with both U-Pb discordance and ??18O. Discordant grains exhibit either a recrystallized, fractured, or strongly zoned CL texture, and are characteristic of 18O depletion. We interpret this to be a result of metamictization, leading to destruction of the zircon lattice and an increased susceptibility to lead loss. Conversely, grains that are concordant have less-expressed zoning and a smoother CL texture and are enriched in 18O. From this it is apparent that various stages of water-rock interaction, as evidenced by systematic variations in ??18O, leave their imprint on both the texture and U-Pb systematics of zircon. Copyright ?? 2005 Elsevier Ltd.
Detection of verbal discordances during sleep.
Perrin, Fabien; Bastuji, Hélène; Garcia-Larrea, Luis
2002-07-19
We used an electrophysiological marker of linguistic discordance, the N400 wave, to investigate how linguistic and pseudo-linguistic stimuli are categorised during sleep as compared to waking. During wakefulness, signs of discordance detection were, as expected, greater for pseudo-words than for real but semantically incongruous words, relative to congruous words. In sleep stage 2 all signs of hierarchic process of discordance disappeared. A new hierarchic process reappeared in paradoxical sleep, which differed from that of waking, responses to pseudo-words being similar to those to congruous words. Linguistic absurdity appears to be accepted in a different manner during paradoxical sleep than during waking, and this might explain why absurd contents are so naturally incorporated into otherwise plausible dream stories.
King, Rachel; Kim, Jiho; Nanfuka, Mastula; Shafic, Murisho; Nyonyitono, Maureen; Galenda, Florence; Moore, David
2017-01-01
Background HIV negative members of serostatus discordant couples are at high risk for HIV acquisition, but few interventions are in place to target them in sub-Saharan Africa. Methods In this study, we interviewed 28 couples, 3 times over a period of one year to understand their perceptions and attitudes around discordance, their relationship dynamics, their HIV risk behaviour, their beliefs and attitudes about antiretroviral therapy (ART) and their views of the community perceptions of discordance and treatment for HIV. Results Findings revealed that at baseline there were multiple complex explanations and interpretations about discordance among discordant couples and their surrounding community. Shifts in beliefs and attitudes about discordance, HIV risk reduction and ART over time were enabled through re-testing negative members of discordant couples and repeat counselling but some beliefs remain solidly embedded in cultural imperatives of the importance of childbearing as well as culturally determined and enforced gender roles. Conclusions Interventions that aim to target discordant couples must embrace the complex and dynamic understandings of HIV diagnosis and treatment in context of fluid relationships, and changing beliefs about HIV risk and treatment. PMID:28081158
Quantum correlations for bipartite continuous-variable systems
NASA Astrophysics Data System (ADS)
Ma, Ruifen; Hou, Jinchuan; Qi, Xiaofei; Wang, Yangyang
2018-04-01
Two quantum correlations Q and Q_P for (m+n)-mode continuous-variable systems are introduced in terms of average distance between the reduced states under the local Gaussian positive operator-valued measurements, and analytical formulas of these quantum correlations for bipartite Gaussian states are provided. It is shown that the product states do not contain these quantum correlations, and conversely, all (m+n)-mode Gaussian states with zero quantum correlations are product states. Generally, Q≥ Q_{P}, but for the symmetric two-mode squeezed thermal states, these quantum correlations are the same and a computable formula is given. In addition, Q is compared with Gaussian geometric discord for symmetric squeezed thermal states.
Application of two tests of multivariate discordancy to fisheries data sets
Stapanian, M.A.; Kocovsky, P.M.; Garner, F.C.
2008-01-01
The generalized (Mahalanobis) distance and multivariate kurtosis are two powerful tests of multivariate discordancies (outliers). Unlike the generalized distance test, the multivariate kurtosis test has not been applied as a test of discordancy to fisheries data heretofore. We applied both tests, along with published algorithms for identifying suspected causal variable(s) of discordant observations, to two fisheries data sets from Lake Erie: total length, mass, and age from 1,234 burbot, Lota lota; and 22 combinations of unique subsets of 10 morphometrics taken from 119 yellow perch, Perca flavescens. For the burbot data set, the generalized distance test identified six discordant observations and the multivariate kurtosis test identified 24 discordant observations. In contrast with the multivariate tests, the univariate generalized distance test identified no discordancies when applied separately to each variable. Removing discordancies had a substantial effect on length-versus-mass regression equations. For 500-mm burbot, the percent difference in estimated mass after removing discordancies in our study was greater than the percent difference in masses estimated for burbot of the same length in lakes that differed substantially in productivity. The number of discordant yellow perch detected ranged from 0 to 2 with the multivariate generalized distance test and from 6 to 11 with the multivariate kurtosis test. With the kurtosis test, 108 yellow perch (90.7%) were identified as discordant in zero to two combinations, and five (4.2%) were identified as discordant in either all or 21 of the 22 combinations. The relationship among the variables included in each combination determined which variables were identified as causal. The generalized distance test identified between zero and six discordancies when applied separately to each variable. Removing the discordancies found in at least one-half of the combinations (k=5) had a marked effect on a principal components
Daemonic ergotropy: enhanced work extraction from quantum correlations
NASA Astrophysics Data System (ADS)
Francica, Gianluca; Goold, John; Plastina, Francesco; Paternostro, Mauro
2017-03-01
We investigate how the presence of quantum correlations can influence work extraction in closed quantum systems, establishing a new link between the field of quantum non-equilibrium thermodynamics and the one of quantum information theory. We consider a bipartite quantum system and we show that it is possible to optimize the process of work extraction, thanks to the correlations between the two parts of the system, by using an appropriate feedback protocol based on the concept of ergotropy. We prove that the maximum gain in the extracted work is related to the existence of quantum correlations between the two parts, quantified by either quantum discord or, for pure states, entanglement. We then illustrate our general findings on a simple physical situation consisting of a qubit system.
Quantum Locality in Game Strategy
NASA Astrophysics Data System (ADS)
Melo-Luna, Carlos A.; Susa, Cristian E.; Ducuara, Andrés F.; Barreiro, Astrid; Reina, John H.
2017-03-01
Game theory is a well established branch of mathematics whose formalism has a vast range of applications from the social sciences, biology, to economics. Motivated by quantum information science, there has been a leap in the formulation of novel game strategies that lead to new (quantum Nash) equilibrium points whereby players in some classical games are always outperformed if sharing and processing joint information ruled by the laws of quantum physics is allowed. We show that, for a bipartite non zero-sum game, input local quantum correlations, and separable states in particular, suffice to achieve an advantage over any strategy that uses classical resources, thus dispensing with quantum nonlocality, entanglement, or even discord between the players’ input states. This highlights the remarkable key role played by pure quantum coherence at powering some protocols. Finally, we propose an experiment that uses separable states and basic photon interferometry to demonstrate the locally-correlated quantum advantage.
Quantum Locality in Game Strategy
Melo-Luna, Carlos A.; Susa, Cristian E.; Ducuara, Andrés F.; Barreiro, Astrid; Reina, John H.
2017-01-01
Game theory is a well established branch of mathematics whose formalism has a vast range of applications from the social sciences, biology, to economics. Motivated by quantum information science, there has been a leap in the formulation of novel game strategies that lead to new (quantum Nash) equilibrium points whereby players in some classical games are always outperformed if sharing and processing joint information ruled by the laws of quantum physics is allowed. We show that, for a bipartite non zero-sum game, input local quantum correlations, and separable states in particular, suffice to achieve an advantage over any strategy that uses classical resources, thus dispensing with quantum nonlocality, entanglement, or even discord between the players’ input states. This highlights the remarkable key role played by pure quantum coherence at powering some protocols. Finally, we propose an experiment that uses separable states and basic photon interferometry to demonstrate the locally-correlated quantum advantage. PMID:28327567
Quantumness and the role of locality on quantum correlations
NASA Astrophysics Data System (ADS)
Bellomo, G.; Plastino, A.; Plastino, A. R.
2016-06-01
Quantum correlations in a physical system are usually studied with respect to a unique and fixed decomposition of the system into subsystems, without fully exploiting the rich structure of the state space. Here, we show several examples in which the consideration of different ways to decompose a physical system enhances the quantum resources and accounts for a more flexible definition of quantumness measures. Furthermore, we give a different perspective regarding how to reassess the fact that local operations play a key role in general quantumness measures that go beyond entanglement—as discordlike ones. We propose a family of measures to quantify the maximum quantumness of a given state. For the discord-based case, we present some analytical results for 2 ×d -dimensional states. Applying our definition to low-dimensional bipartite states, we show that different behaviors can be reported for separable and entangled states vis-à-vis those corresponding to the usual measures of quantum correlations. We show that there is a close link between our proposal and the criterion to witness quantum correlations based on the rank of the correlation matrix, proposed by Dakić, Vedral, and Brukner [Phys. Rev. Lett. 105, 190502 (2010), 10.1103/PhysRevLett.105.190502].
Weksberg, Rosanna; Shuman, Cheryl; Caluseriu, Oana; Smith, Adam C; Fei, Yan-Ling; Nishikawa, Joy; Stockley, Tracy L; Best, Lyle; Chitayat, David; Olney, Ann; Ives, Elizabeth; Schneider, Adele; Bestor, Timothy H; Li, Madeline; Sadowski, Paul; Squire, Jeremy
2002-05-15
Beckwith-Wiedemann syndrome (BWS) presents with visceromegaly, macroglossia, tumor predisposition and other congenital abnormalities, and is usually associated with abnormalities of chromosome 11p15. A number of identical twin pairs, mostly female, have been reported to be discordant for BWS. We show here that the incidence of female monozygotic twins among patients with BWS is dramatically increased over that of the general population. A cluster of imprinted genes within 11p15 is thought to be coordinately regulated via the imprinted expression of KCNQ1OT1, which encodes an untranslated RNA. In skin fibroblasts from five monozygotic twin pairs discordant for BWS, each affected twin had an imprinting defect at KCNQ1OT1 on 11p15, whereas the unaffected twin did not. Five additional monozygotic twin pairs, for whom only blood was available, also displayed an imprinting defect at KCNQ1OT1. It is possible that discordance for BWS in MZ twins is due to unequal splitting of the inner cell mass during twinning, thereby causing differential maintenance of imprinting at KCNQ1OT1. Alternatively, we propose that KCNQ1OT1 is especially vulnerable to a loss of imprinting event, caused by a lack of maintenance DNA methylation at a critical stage of preimplantation development, and that this loss of imprinting predisposes to twinning as well as to discordance for BWS. These data underscore the importance of continued surveillance of children born following assisted reproductive technologies that impact the preimplantation embryo.
One-Way Deficit and Quantum Phase Transitions in XX Model
NASA Astrophysics Data System (ADS)
Wang, Yao-Kun; Zhang, Yu-Ran
2018-02-01
Quantum correlations including entanglement and quantum discord have drawn much attention in characterizing quantum phase transitions. Quantum deficit originates in questions regarding work extraction from quantum systems coupled to a heat bath (Oppenheim et al. Phys. Rev. Lett. 89, 180402, 2002). It links quantum thermodynamics with quantum correlations and provides a new standpoint for understanding quantum non-locality. In this paper, we evaluate the one-way deficit of two adjacent spins in the bulk for the XX model. In the thermodynamic limit, the XX model undergoes a first order transition from fully polarized to a critical phase with quasi-long-range order with decrease of quantum parameter. We find that the one-way deficit becomes nonzero after the critical point. Therefore, the one-way deficit characterizes the quantum phase transition in the XX model.
Heat engine driven by purely quantum information.
Park, Jung Jun; Kim, Kang-Hwan; Sagawa, Takahiro; Kim, Sang Wook
2013-12-06
The key question of this Letter is whether work can be extracted from a heat engine by using purely quantum mechanical information. If the answer is yes, what is its mathematical formula? First, by using a bipartite memory we show that the work extractable from a heat engine is bounded not only by the free energy change and the sum of the entropy change of an individual memory but also by the change of quantum mutual information contained inside the memory. We then find that the engine can be driven by purely quantum information, expressed as the so-called quantum discord, forming a part of the quantum mutual information. To confirm it, as a physical example we present the Szilard engine containing a diatomic molecule with a semipermeable wall.
Lipid discordance and carotid plaque in obese patients in primary prevention.
Masson, Walter; Siniawski, Daniel; Lobo, Martín; Molinero, Graciela
2018-01-01
Obese patients with lipid discordance (non-HDL cholesterol levels 30mg/dL above the LDL-c value) may have a greater prevalence of carotid atherosclerotic plaque (CAP). Our study objectives were: 1) To assess the prevalence of lipid discordance in a primary prevention population of obese patients; 2) To investigate the association between lipid discordance and presence of CAP. Obese subjects aged >18 years (BMI ≥30kg/m 2 ) with no cardiovascular disease, diabetes, or lipid-lowering treatment from six cardiology centers were included. Lipid discordance was defined when, regardless of the LDL-c level, the non-HDL cholesterol value exceeded the LDL-c value by 30mg/dL. Presence of CAP was identified by ultrasonography. Univariate and multivariate analyses were performed to explore the association between lipid discordance and presence of CAP. The study simple consisted of 325 obese patients (57.2% men; mean age, 52.3 years). Prevalence of lipid discordance was 57.9%. CAP was found in 38.6% of patients, but the proportion was higher in subjects with lipid discordance as compared to those without this lipid pattern (44.4% vs. 30.7%, P=.01). In both the univariate (OR: 1.80; 95% CI: 1.14-2.87; P=.01) and the multivariate analysis (OR: 2.07; 95% CI: 1.22-3.54; P=.007), presence of lipid discordance was associated to an increased probability of CAP. In these obese patients, lipid discordance was associated to greater prevalence of CAP. Evaluation of obese patients with this strategy could help identify subjects with higher residual cardiovascular risk. Copyright © 2017 SEEN y SED. Publicado por Elsevier España, S.L.U. All rights reserved.
NASA Astrophysics Data System (ADS)
Qin, Meng; Li, Yan-Biao; Wu, Fang-Ping
2014-07-01
Quantifying and understanding quantum correlations may give a direct reply for many issues regarding the interesting behaviors of quantum system. To explore the quantum correlations in quantum teleportation, we have used a two-qubit Heisenberg XYZ system with spin-orbit interaction as a quantum channel to teleport an unknown state. By using different measures and standard teleportation protocols, we have derived the analytical expressions for quantum discord, entanglement of formation, purity, and maximal teleportation fidelity of the system. We compare their different characteristics and analyze the relationships between these quantities.
van Dongen, Jenny; Willemsen, Gonneke; Heijmans, Bastiaan T.; Neuteboom, Jacoline; Kluft, Cornelis; Jansen, Rick; Penninx, Brenda W.J.; Slagboom, P. Eline; de Geus, Eco J.C.; Boomsma, Dorret I.
2015-01-01
Background BMI discordant monozygotic (MZ) twins allows an examination of the causes and consequences of adiposity in a genetically controlled design. Few studies have examined longitudinal BMI discordance in MZ pairs. Objectives To study the development over time of BMI discordance in adolescent and adult MZ twin pairs, and to examine lifestyle, metabolic, inflammatory, and gene expression differences associated with concurrent and long-term BMI discordance in MZ pairs. Subjects/Methods BMI data from 2775 MZ twin pairs, collected in eight longitudinal surveys and a biobank project between 1991 and 2011, were analyzed to characterize longitudinal discordance. Lifestyle characteristics were compared within discordant pairs (ΔBMI ≥ 3 kg/m2) and biomarkers (lipids, glucose, insulin, CRP, fibrinogen, IL-6, TNF-α and sIL-6R and liver enzymes AST, ALT and GGT) and gene expression were compared in peripheral blood from discordant pairs who participated in the NTR biobank project. Results The prevalence of discordance ranged from 3.2% in 1991 (mean age=17, SD=2.4) to 17.4% (N=202 pairs) in 2009 (mean age=35, SD=15), and was 16.5% (N=174) among pairs participating in the biobank project (mean age=35, SD=12). Of 699 MZ with BMI data from 3-5 time points, 17 pairs (2.4%) were long-term discordant (at all available time points; mean follow-up range=6.4 years). Concurrently discordant pairs showed significant differences in self-ratings of which twin eats most (p=2.3×10−13), but not in leisure time exercise activity (p=0.28) and smoking (p>0.05). Ten out of 14 biomarkers showed significantly more unfavorable levels in the heavier of twin of the discordant pairs (p-values < 0.001); most of these biomarker differences were largest in longitudinally discordant pairs. No significant gene expression differences were identified, although high ranking genes were enriched for Gene Ontology (GO) terms highlighting metabolic gene regulation and inflammation pathways. Conclusions
Food reinforcement and delay discounting in zBMI-discordant siblings.
Feda, Denise M; Roemmich, James N; Roberts, April; Epstein, Leonard H
2015-02-01
The interaction of food reinforcement and the inability to delay gratification are related to adult energy intake and obesity. This study was designed to test the association of sibling pair differences in relative reinforcing efficacy of food and delay discounting on sibling pair differences in zBMI scores of same-gender zBMI-discordant siblings. We tested main and interactive relationships between delay discounting and relative reinforcing efficacy of food on zBMI discordance in 14 zBMI-discordant biological sibling pairs (6 female pairs) using a discordant sibling study design. Sibling pair differences in relative reinforcing efficacy of food were associated with sibling pair differences in zBMI (p= 0.046); this effect was moderated by delay discounting (p <0.002). Sibling pairs with greater differences in relative reinforcing efficacy and delay discounting had greater differences in zBMI. The combination of greater sibling pair differences in delay discounting and relative reinforcing efficacy is associated with greater discordance in zBMI in adolescent sibling pairs. Copyright © 2014 Elsevier Ltd. All rights reserved.
Sexual Orientation Discordance and Nonfatal Suicidal Behaviors in U.S. High School Students.
Annor, Francis B; Clayton, Heather B; Gilbert, Leah K; Ivey-Stephenson, Asha Z; Irving, Shalon M; David-Ferdon, Corinne; Kann, Laura K
2018-04-01
Studies among adults have documented association between sexual orientation discordance and some suicide risk factors. However, studies examining sexual orientation discordance and nonfatal suicidal behaviors in youth are rare. This study examines the association between sexual orientation discordance and suicidal ideation/suicide attempts among a nationally representative sample of U.S. high school students. Using sexual identity and sex of sexual contact measures from the 2015 national Youth Risk Behavior Survey (n=6,790), a sexual orientation discordance variable was constructed describing concordance and discordance (agreement and disagreement, respectively, between sexual identity and sex of sexual contacts). Three suicide-related questions (seriously considered attempting suicide, making a plan about how they would attempt suicide, and attempting suicide) were combined to create a two-level nonfatal suicide risk variable. Analyses were restricted to students who identified as heterosexual or gay/lesbian, who had sexual contact, and who had no missing data for sex or suicide variables. The association between sexual orientation discordance and nonfatal suicide risk was assessed using logistic regression. Analyses were performed in 2017. Approximately 4.0% of students experienced sexual orientation discordance. High suicide risk was significantly more common among discordant students compared with concordant students (46.3% vs 22.4%, p<0.0001). In adjusted models, discordant students were 70% more likely to have had suicidal ideation/suicide attempts compared with concordant students (adjusted prevalence ratio=1.7, 95% CI=1.4, 2.0). Sexual orientation discordance was associated with increased likelihood of nonfatal suicidal behaviors. Discordant adolescents may experience unique stressors that should be considered when developing and implementing suicide prevention programs. Published by Elsevier Inc.
Determinants of Patient-Oncologist Prognostic Discordance in Advanced Cancer
Gramling, Robert; Fiscella, Kevin; Xing, Guibo; Hoerger, Michael; Duberstein, Paul; Plumb, Sandy; Mohile, Supriya; Fenton, Joshua J.; Tancredi, Daniel J.; Kravitz, Richard L.; Epstein, Ronald M.
2018-01-01
IMPORTANCE Patients with advanced cancer often report expectations for survival that differ from their oncologists’ expectations. Whether patients know that their survival expectations differ from those of their oncologists remains unknown. This distinction is important because knowingly expressing differences of opinion is important for shared decision making, whereas patients not knowing that their understanding differs from that of their treating physician is a potential marker of inadequate communication. OBJECTIVE To describe the prevalence, distribution, and proportion of prognostic discordance that is due to patients’ knowingly vs unknowingly expressing an opinion that differs from that of their oncologist. DESIGN, SETTING, AND PARTICIPANTS Cross-sectional study conducted at academic and community oncology practices in Rochester, New York, and Sacramento, California. The sample comprises 236 patients with advanced cancer and their 38 oncologists who participated in a randomized trial of an intervention to improve clinical communication. Participants were enrolled from August 2012 to June 2014 and followed up until October 2015. MAIN OUTCOMES AND MEASURES We ascertained discordance by comparing patient and oncologist ratings of 2-year survival probability. For discordant pairs, we determined whether patients knew that their opinions differed from those of their oncologists by asking the patients to report how they believed their oncologists rated their 2-year survival. RESULTS Among the 236 patients (mean [SD] age, 64.5 [11.4] years; 54%female), 161 patient-oncologist survival prognosis ratings (68%; 95%CI, 62%–75%) were discordant. Discordance was substantially more common among nonwhite patients compared with white patients (95%[95%CI, 86%–100%] vs 65%[95%CI, 58%–73%], respectively; P = .03). Among 161 discordant patients, 144 (89%) did not know that their opinions differed from that of their oncologists and nearly all of them (155 of 161 [96
Role of Weak Measurements on States Ordering and Monogamy of Quantum Correlation
NASA Astrophysics Data System (ADS)
Hu, Ming-Liang; Fan, Heng; Tian, Dong-Ping
2015-01-01
The information-theoretic definition of quantum correlation, e.g., quantum discord, is measurement dependent. By considering the more general quantum measurements, weak measurements, which include the projective measurement as a limiting case, we show that while weak measurements can enable one to capture more quantumness of correlation in a state, it can also induce other counterintuitive quantum effects. Specifically, we show that the general measurements with different strengths can impose different orderings for quantum correlations of some states. It can also modify the monogamous character for certain classes of states as well which may diminish the usefulness of quantum correlation as a resource in some protocols. In this sense, we say that the weak measurements play a dual role in defining quantum correlation.
Van Mieghem, T; Eixarch, E; Gucciardo, L; Done, E; Gonzales, I; Van Schoubroeck, D; Lewi, L; Gratacos, E; Deprest, J
2011-01-01
The aim of this study was to identify predictors of twin-to-twin transfusion syndrome (TTTS) and selective intrauterine growth restriction (sIUGR) in monochorionic diamniotic (MCDA) twin pregnancies with moderate amniotic fluid discordance (mAFD). Monochorionic twins with mAFD (n = 45; gestational age, 15-29 weeks) were assessed for extent of fluid discordance, fetal growth discordance and fetal cardiac dysfunction, and were followed longitudinally. A prediction algorithm was constructed for TTTS and sIUGR and validated in an unrelated cohort (n = 52). Cardiac dysfunction could not predict TTTS or sIUGR. Twins below 20 weeks of gestation with a fluid discordance of ≥ 3.1 cm had a risk of TTTS of 85.7%. Sensitivity for TTTS was nevertheless only 55%. An intertwin weight discordance of ≥ 25% had 63% sensitivity and 76% specificity for sIUGR without TTTS. The outcome of MCDA twins with mAFD remains unpredictable, yet high-risk and low-risk subgroups for TTTS can be identified based on severity of fluid discordance and gestational age.
[Perinatal management of twins with discordant congenital defects].
Yu, Hai-yan; Xing, Ai-yun; You, Yong; Liu, Xing-hui; Wang, Xiao-dong
2014-11-01
To review the outcomes of perinatal management of twins with discordant congenital defects. We retrospectively examined the cases of twins with discordant congenital defects treated in the West China Second University Hospital from December 2011 to December 2013. There were 26 cases of twins (14 dichorionic and 12 monochorionic) with one anomalous fetus. Of those twins, 16 were conceived by nature and 10 by in vitro fertilization and embryo tansfer (IVF-ET). Counselling services were offered to the parents by a multidisciplinary team about options of pregnancy. Termination of pregnancy was chosen on three monochorionic twins. Twelve pairs of twin were delivered at 26(+3)-37(+6) weeks gestation. One pair ended with neonatal death, and another one with gastroschisis was given intrapartum fetal operation. Selective termination was chosen on 11 cases using intracardiac injection of potassium chloride under ultrasonographic guidance (9 cases) or bipolar cord coagulation (2 cases). This resulted in ten live births delivered at 25(+5)-38(+4) gustation and one neonatal death. Early diagnosis of twins with discordant congenital defects is important. Multidisciplinary counselling services to parents are recommended for determination of options. Intensive prenatal care is essential in management of twins with discordant congenital defects.
Generic emergence of classical features in quantum Darwinism.
Brandão, Fernando G S L; Piani, Marco; Horodecki, Paweł
2015-08-12
Quantum Darwinism posits that only specific information about a quantum system that is redundantly proliferated to many parts of its environment becomes accessible and objective, leading to the emergence of classical reality. However, it is not clear under what conditions this mechanism holds true. Here we prove that the emergence of classical features along the lines of quantum Darwinism is a general feature of any quantum dynamics: observers who acquire information indirectly through the environment have effective access at most to classical information about one and the same measurement of the quantum system. Our analysis does not rely on a strict conceptual splitting between a system-of-interest and its environment, and allows one to interpret any system as part of the environment of any other system. Finally, our approach leads to a full operational characterization of quantum discord in terms of local redistribution of correlations.
Generic emergence of classical features in quantum Darwinism
NASA Astrophysics Data System (ADS)
Brandão, Fernando G. S. L.; Piani, Marco; Horodecki, Paweł
2015-08-01
Quantum Darwinism posits that only specific information about a quantum system that is redundantly proliferated to many parts of its environment becomes accessible and objective, leading to the emergence of classical reality. However, it is not clear under what conditions this mechanism holds true. Here we prove that the emergence of classical features along the lines of quantum Darwinism is a general feature of any quantum dynamics: observers who acquire information indirectly through the environment have effective access at most to classical information about one and the same measurement of the quantum system. Our analysis does not rely on a strict conceptual splitting between a system-of-interest and its environment, and allows one to interpret any system as part of the environment of any other system. Finally, our approach leads to a full operational characterization of quantum discord in terms of local redistribution of correlations.
Food reinforcement and delay discounting in zBMI-discordant siblings ☆
Feda, Denise M.; Roemmich, James N.; Roberts, April; Epstein, Leonard H.
2014-01-01
Objective The interaction of food reinforcement and the inability to delay gratification are related to adult energy intake and obesity. This study was designed to test the association of sibling pair differences in relative reinforcing efficacy of food and delay discounting on sibling pair differences in zBMI scores of same-gender zBMI-discordant siblings. Design and methods We tested main and interactive relationships between delay discounting and relative reinforcing efficacy of food on zBMI discordance in 14 zBMI-discordant biological sibling pairs (6 female pairs) using a discordant sibling study design. Results Sibling pair differences in relative reinforcing efficacy of food were associated with sibling pair differences in zBMI (p = 0.046); this effect was moderated by delay discounting (p < 0.002). Sibling pairs with greater differences in relative reinforcing efficacy and delay discounting had greater differences in zBMI. Conclusions The combination of greater sibling pair differences in delay discounting and relative reinforcing efficacy is associated with greater discordance in zBMI in adolescent sibling pairs. PMID:25464024
NASA Astrophysics Data System (ADS)
Cruz, C.
The characterization of quantum information quantifiers has attracted a considerable attention of the scientific community, since they are a useful tool to verify the presence of quantum correlations in a quantum system. In this context, in the present work we show a theoretical study of some quantifiers, such as entanglement witness, entanglement of formation, Bell’s inequality violation and geometric quantum discord as a function of the diffractive properties of neutron scattering. We provide one path toward identifying the presence of quantum correlations and quantum nonlocality in a molecular magnet as a Heisenberg spin-1/2 dimer, by diffractive properties typically obtained via neutron scattering experiments.
Sharp, Wendy S; Gottesman, Rebecca F; Greenstein, Deanna K; Ebens, Christen L; Rapoport, Judith L; Castellanos, F Xavier
2003-01-01
Nongenetic factors and phenomenology of attention-deficit/hyperactivity disorder (ADHD) were examined in monozygotic (MZ) twin pairs discordant for ADHD. Recruitment included telephone screening (n = 297 pairs), behavioral ratings obtained from parents and teachers (n = 59 pairs), and, finally, in-person assessment (n = 25 pairs; structured classroom observation, diagnostic interview, psychoeducational evaluation, birth record review, establishment of monozygosity, and anatomic brain imaging). Affected twins were further contrasted with previously studied affected singletons. Of the 25 MZ twin pairs qualifying for in-person evaluation, only 10 proved discordant for ADHD. Affected twins were mostly comparable with affected singletons on clinical measures, although fathers' self-ratings of childhood ADHD status were significantly lower in twins than in singletons. Discordance for ADHD in MZ twins appears to be ascribable to greater environmental discordance and decreased familiality. Despite these differences, affected twins were phenotypically comparable with affected singletons. Thus MZ twins discordant for ADHD, while rare, can inform research on the etiology and pathophysiology of this disorder.
Fasting plasma total ghrelin concentrations in monozygotic twins discordant for obesity.
Leskelä, Piia; Ukkola, Olavi; Vartiainen, Johanna; Rönnemaa, Tapani; Kaprio, Jaakko; Bouchard, Claude; Kesäniemi, Y Antero
2009-02-01
Ghrelin is a hormone that is involved in the regulation of food intake. Neuronal, endocrine, and genetic factors have been shown to regulate plasma ghrelin levels; but the determinants of fasting ghrelin concentrations are not yet fully understood. The main aim was to explore the roles of adiposity and genetic differences in determining fasting plasma total ghrelin levels. We measured total ghrelin levels in a population of 23 monozygotic twin pairs discordant for obesity. In addition, 2 variants of ghrelin gene, namely, Arg51Gln and Leu72Met, were genotyped in 3 populations of monozygotic twin pairs: 23 obesity-discordant, 43 lean-concordant, and 46 obesity-concordant twin pairs. In discordant twins, lean co-twins had higher fasting plasma total ghrelin levels (950 pg/mL, SD = 328 pg/mL) than obese twins (720 pg/mL, SD = 143 pg/mL; P = .003). Arg51Gln-polymorphism of the ghrelin gene was equally distributed between the twin groups. However, there were significant differences in genotype frequencies at the Leu72Met polymorphism between the discordant and obese-concordant groups (P = .003) and between the discordant and lean-concordant groups (P = .011), but not between the 2 concordant groups. In the discordant group, there were fewer Met carriers (4%) than among the obese (17%) or the lean-concordant groups (15%). Plasma total ghrelin levels are affected by acquired obesity independent of genetic background. The Leu72 allele is particularly common among monozygotic twins discordant for obesity, suggesting that this ghrelin allele is more permissive in the regulation of energy balance. The ghrelin gene may thus play a role in the regulation of variability of body weight, such that Leu72 allele carriers are more prone to weight variability in response to environmental factors.
Moran, Nicola; Plomin, Robert
2017-01-01
Using a qualitative monozygotic (MZ) twin differences design we explored whether adolescent MZ twins report discordant peer relationships and, if so, whether they perceive them as causes, consequences or correlates of discordant behaviour. We gathered free-response questionnaire data from 497 families and conducted in-depth telephone interviews with 97 of them. Within this dataset n = 112 families (23% of the sample) described discordant peer relationships. Six categories of discordance were identified (peer victimisation, peer rejection, fewer friends, different friends, different attitudes to friendship and dependence on co-twin). Participants described peer relationship discordance arising as a result of chance occurrences, enhanced vulnerability in one twin or discordant behaviour. Consequences of discordant peer relationships were seen as discordance in self-confidence, future plans, social isolation, mental health and interests. In all cases the twin with worse peer experiences was seen as having a worse outcome. Specific hypotheses are presented. PMID:28727730
Quantum reversibility is relative, or does a quantum measurement reset initial conditions?
Zurek, Wojciech H
2018-07-13
I compare the role of the information in classical and quantum dynamics by examining the relation between information flows in measurements and the ability of observers to reverse evolutions. I show that in the Newtonian dynamics reversibility is unaffected by the observer's retention of the information about the measurement outcome. By contrast-even though quantum dynamics is unitary, hence, reversible-reversing quantum evolution that led to a measurement becomes, in principle, impossible for an observer who keeps the record of its outcome. Thus, quantum irreversibility can result from the information gain rather than just its loss-rather than just an increase of the (von Neumann) entropy. Recording of the outcome of the measurement resets, in effect, initial conditions within the observer's (branch of) the Universe. Nevertheless, I also show that the observer's friend-an agent who knows what measurement was successfully carried out and can confirm that the observer knows the outcome but resists his curiosity and does not find out the result-can, in principle, undo the measurement. This relativity of quantum reversibility sheds new light on the origin of the arrow of time and elucidates the role of information in classical and quantum physics. Quantum discord appears as a natural measure of the extent to which dissemination of information about the outcome affects the ability to reverse the measurement.This article is part of a discussion meeting issue 'Foundations of quantum mechanics and their impact on contemporary society'. © 2018 The Author(s).
Intratumoral heterogeneity as a source of discordance in breast cancer biomarker classification.
Allott, Emma H; Geradts, Joseph; Sun, Xuezheng; Cohen, Stephanie M; Zirpoli, Gary R; Khoury, Thaer; Bshara, Wiam; Chen, Mengjie; Sherman, Mark E; Palmer, Julie R; Ambrosone, Christine B; Olshan, Andrew F; Troester, Melissa A
2016-06-28
Spatial heterogeneity in biomarker expression may impact breast cancer classification. The aims of this study were to estimate the frequency of spatial heterogeneity in biomarker expression within tumors, to identify technical and biological factors contributing to spatial heterogeneity, and to examine the impact of discordant biomarker status within tumors on clinical record agreement. Tissue microarrays (TMAs) were constructed using two to four cores (1.0 mm) for each of 1085 invasive breast cancers from the Carolina Breast Cancer Study, which is part of the AMBER Consortium. Immunohistochemical staining for estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2) was quantified using automated digital imaging analysis. The biomarker status for each core and for each case was assigned using clinical thresholds. Cases with core-to-core biomarker discordance were manually reviewed to distinguish intratumoral biomarker heterogeneity from misclassification of biomarker status by the automated algorithm. The impact of core-to-core biomarker discordance on case-level agreement between TMAs and the clinical record was evaluated. On the basis of automated analysis, discordant biomarker status between TMA cores occurred in 9 %, 16 %, and 18 % of cases for ER, PR, and HER2, respectively. Misclassification of benign epithelium and/or ductal carcinoma in situ as invasive carcinoma by the automated algorithm was implicated in discordance among cores. However, manual review of discordant cases confirmed spatial heterogeneity as a source of discordant biomarker status between cores in 2 %, 7 %, and 8 % of cases for ER, PR, and HER2, respectively. Overall, agreement between TMA and clinical record was high for ER (94 %), PR (89 %), and HER2 (88 %), but it was reduced in cases with core-to-core discordance (agreement 70 % for ER, 61 % for PR, and 57 % for HER2). Intratumoral biomarker heterogeneity may impact breast
A self-contained quantum harmonic engine
NASA Astrophysics Data System (ADS)
Reid, B.; Pigeon, S.; Antezza, M.; De Chiara, G.
2017-12-01
We propose a system made of three quantum harmonic oscillators as a compact quantum engine for producing mechanical work. The three oscillators play respectively the role of the hot bath, the working medium and the cold bath. The working medium performs an Otto cycle during which its frequency is changed and it is sequentially coupled to each of the two other oscillators. As the two environments are finite, the lifetime of the machine is finite and after a number of cycles it stops working and needs to be reset. Remarkably, we show that this machine can extract more than 90% of the available energy during 70 cycles. Differently from usually investigated infinite-reservoir configurations, this machine allows the protection of induced quantum correlations and we analyse the entanglement and quantum discord generated during the strokes. Interestingly, we show that high work generation is always accompanied by large quantum correlations. Our predictions can be useful for energy management at the nanoscale, and can be relevant for experiments with trapped ions and experiments with light in integrated optical circuits.
Distribution of Bell-inequality violation versus multiparty-quantum-correlation measures
NASA Astrophysics Data System (ADS)
Sharma, Kunal; Das, Tamoghna; Sen (de), Aditi; Sen, Ujjwal
Violation of a Bell inequality guarantees the existence of quantum correlations in a shared quantum state. A pure bipartite quantum state, having nonvanishing quantum correlation, always violates a Bell inequality. Such correspondence is absent for multipartite pure quantum states in the case of multipartite correlation function Bell inequalities with two settings at each site. We establish a connection between the monogamy of Bell-inequality violation and multiparty quantum correlations for shared multisite quantum states. We believe that the relation is generic, as it is true for a number of different multisite measures that are defined from radically different perspectives. Precisely, we quantify the multisite-quantum-correlation content in the states by generalized geometric measure, a genuine multisite entanglement measure, as well as three monogamybased multiparty-quantum-correlation measures, viz., 3-tangle, quantum-discord score, and quantum-work-deficit score. We find that generalized Greenberger-Horne-Zeilinger states and another single-parameter family of states, which we refer to as the special Greenberger-Horne-Zeilinger states, have the status of extremal states in such relations.
Distribution of Bell-inequality violation versus multiparty-quantum-correlation measures
NASA Astrophysics Data System (ADS)
Sharma, Kunal; Das, Tamoghna; SenDe, Aditi; Sen, Ujjwal
2016-06-01
Violation of a Bell inequality guarantees the existence of quantum correlations in a shared quantum state. A pure bipartite quantum state, having nonvanishing quantum correlation, always violates a Bell inequality. Such correspondence is absent for multipartite pure quantum states in the case of multipartite correlation function Bell inequalities with two settings at each site. We establish a connection between the monogamy of Bell-inequality violation and multiparty quantum correlations for shared multisite quantum states. We believe that the relation is generic, as it is true for a number of different multisite measures that are defined from radically different perspectives. Precisely, we quantify the multisite-quantum-correlation content in the states by generalized geometric measure, a genuine multisite entanglement measure, as well as three monogamy-based multiparty-quantum-correlation measures, viz., 3-tangle, quantum-discord score, and quantum-work-deficit score. We find that generalized Greenberger-Horne-Zeilinger states and another single-parameter family of states, which we refer to as the special Greenberger-Horne-Zeilinger states, have the status of extremal states in such relations.
Time Series Discord Detection in Medical Data using a Parallel Relational Database
DOE Office of Scientific and Technical Information (OSTI.GOV)
Woodbridge, Diane; Rintoul, Mark Daniel; Wilson, Andrew T.
Recent advances in sensor technology have made continuous real-time health monitoring available in both hospital and non-hospital settings. Since data collected from high frequency medical sensors includes a huge amount of data, storing and processing continuous medical data is an emerging big data area. Especially detecting anomaly in real time is important for patients’ emergency detection and prevention. A time series discord indicates a subsequence that has the maximum difference to the rest of the time series subsequences, meaning that it has abnormal or unusual data trends. In this study, we implemented two versions of time series discord detection algorithmsmore » on a high performance parallel database management system (DBMS) and applied them to 240 Hz waveform data collected from 9,723 patients. The initial brute force version of the discord detection algorithm takes each possible subsequence and calculates a distance to the nearest non-self match to find the biggest discords in time series. For the heuristic version of the algorithm, a combination of an array and a trie structure was applied to order time series data for enhancing time efficiency. The study results showed efficient data loading, decoding and discord searches in a large amount of data, benefiting from the time series discord detection algorithm and the architectural characteristics of the parallel DBMS including data compression, data pipe-lining, and task scheduling.« less
Thermal Quantum Correlations in Photosynthetic Light-Harvesting Complexes
NASA Astrophysics Data System (ADS)
Mahdian, M.; Kouhestani, H.
2015-08-01
Photosynthesis is one of the ancient biological processes, playing crucial role converting solar energy to cellular usable currency. Environmental factors and external perturbations has forced nature to choose systems with the highest efficiency and performance. Recent theoretical and experimental studies have proved the presence of quantum properties in biological systems. Energy transfer systems like Fenna-Matthews-Olson (FMO) complex shows quantum entanglement between sites of Bacteriophylla molecules in protein environment and presence of decoherence. Complex biological systems implement more truthful mechanisms beside chemical-quantum correlations to assure system's efficiency. In this study we investigate thermal quantum correlations in FMO protein of the photosynthetic apparatus of green sulfur bacteria by quantum discord measure. The results confirmed existence of remarkable quantum correlations of of BChla pigments in room temperature. This results approve involvement of quantum correlation mechanisms for information storage and retention in living organisms that could be useful for further evolutionary studies. Inspired idea of this study is potentially interesting to practice by the same procedure in genetic data transfer mechanisms.
A Discordance Weighting Approach Estimating Occupational and Income Returns to Education.
Andersson, Matthew A
2018-04-23
Schooling differences between identical twins are often utilized as a natural experiment to estimate returns to education. Despite longstanding doubts about the truly random nature of within-twin-pair schooling discordance, such discordance has not yet been understood comprehensively, in terms of diverse between- and within-family peer, academic, familial, social, and health exposures. Here, a predictive analysis using national U.S. midlife twin data shows that within-pair schooling differences are endogenous to a variety of childhood exposures. Using discordance propensities, returns to education under a true natural experiment are simulated. Results for midlife occupation and income reveal differences in estimated returns to education that are statistically insignificant, suggesting that twin-based estimates of causal effects are robust. Moreover, identical and fraternal twins show similar levels of discordance endogeneity and similar responses to propensity weighting, suggesting that the identical twins may not provide demonstrably better leverage in the causal identification of educational returns.
[Transcervical Embryoscopy after Missed Abortion in Monoamniotic Twins with Discordant Exencephaly].
Engels, A C; Haide, S; Schanz, K; Knabl, J; Bartzsch, F; Kainer, F
2016-06-01
Monoamniotic twins are considered a cause of high-risk pregnancies. Thereby, discordant malformations do occur rarely. A discordant exencephaly has been described in only a few cases. Transcervical embryoscopy can be performed in cases of monoamniotic twins with missed abortion directly before the abort-curettage. The case of a 35-year-old G1/P0 women in the 12(th) week of pregnancy is described. She had a monoamniotic twin pregnancy with discordant exencephaly and missed abortion diagnosed at 11+2 weeks. A transcervical embryoscopy was performed immediately before the abort-curettage and identified the discordant exencephaly and an additional umbilical cord knot of the 2 foetuses as a probable cause for the abortion. The transcervical embryoscopy lead in our case report to the diagnosis of a umbilical cord knot in a monoamniotic twin pregnancy with missed abortion. We also identified a discordant exencephaly by embryoscopy. With blunt access to the amniotic cavity, the transcervical embryoscopy applies only a minor additional risk to the abort-curettage. However, it should only be performed when the patient explicitly asks for enhanced diagnostics. Transcervical embryoscopy can be performed as an additional diagnostic tool in cases of monoamniotic twins with missed abortion. However, a detailed risk-benefit analysis should be done upfront in consultation with the patient. © Georg Thieme Verlag KG Stuttgart · New York.
NASA Astrophysics Data System (ADS)
Staver, John R.
2010-03-01
Science and religion exhibit multiple relationships as ways of knowing. These connections have been characterized as cousinly, mutually respectful, non-overlapping, competitive, proximate-ultimate, dominant-subordinate, and opposing-conflicting. Some of these ties create stress, and tension between science and religion represents a significant chapter in humans' cultural heritage before and since the Enlightenment. Truth, knowledge, and their relation are central to science and religion as ways of knowing, as social institutions, and to their interaction. In religion, truth is revealed through God's word. In science, truth is sought after via empirical methods. Discord can be viewed as a competition for social legitimization between two social institutions whose goals are explaining the world and how it works. Under this view, the root of the discord is truth as correspondence. In this concept of truth, knowledge corresponds to the facts of reality, and conflict is inevitable for many because humans want to ask which one—science or religion—gets the facts correct. But, the root paradox, also known as the problem of the criterion, suggests that seeking to know nature as it is represents a fruitless endeavor. The discord can be set on new ground and resolved by taking a moderately skeptical line of thought, one which employs truth as coherence and a moderate form of constructivist epistemology. Quantum mechanics and evolution as scientific theories and scientific research on human consciousness and vision provide support for this line of argument. Within a constructivist perspective, scientists would relinquish only the pursuit of knowing reality as it is. Scientists would retain everything else. Believers who hold that religion explains reality would come to understand that God never revealed His truth of nature; rather, He revealed His truth in how we are to conduct our lives.
Discordant CSF/plasma HIV-1 RNA in patients with unexplained low-level viraemia.
Nightingale, Sam; Geretti, Anna Maria; Beloukas, Apostolos; Fisher, Martin; Winston, Alan; Else, Laura; Nelson, Mark; Taylor, Stephen; Ustianowski, Andrew; Ainsworth, Jonathan; Gilson, Richard; Haddow, Lewis; Ong, Edmund; Watson, Victoria; Leen, Clifford; Minton, Jane; Post, Frank; Pirmohamed, Munir; Solomon, Tom; Khoo, Saye
2016-12-01
The central nervous system has been proposed as a sanctuary site where HIV can escape antiretroviral control and develop drug resistance. HIV-1 RNA can be at higher levels in CSF than plasma, termed CSF/plasma discordance. We aimed to examine whether discordance in CSF is associated with low level viraemia (LLV) in blood. In this MRC-funded multicentre study, we prospectively recruited patients with LLV, defined as one or more episode of unexplained plasma HIV-1 RNA within 12 months, and undertook CSF examination. Separately, we prospectively collected CSF from patients undergoing lumbar puncture for a clinical indication. Patients with durable suppression of viraemia and no evidence of CNS infection were identified as controls from this group. Factors associated with CSF/plasma HIV-1 discordance overall were examined. One hundred fifty-three patients were recruited across 13 sites; 40 with LLV and 113 undergoing clinical lumbar puncture. Seven of the 40 (18 %) patients with LLV had CSF/plasma discordance, which was significantly more than 0/43 (0 %) with durable suppression in blood from the clinical group (p = 0.005). Resistance associated mutations were shown in six CSF samples from discordant patients with LLV (one had insufficient sample for testing), which affected antiretroviral therapy at sampling in five. Overall discordance was present in 20/153 (13 %) and was associated with nadir CD4 but not antiretroviral concentrations in plasma or CSF. CSF/plasma discordance is observed in patients with LLV and is associated with antiretroviral resistance associated mutations in CSF. The implications for clinical practice require further investigation.
Gut microbiomes of Malawian twin pairs discordant for kwashiorkor
Smith, Michelle I.; Yatsunenko, Tanya; Manary, Mark J.; Trehan, Indi; Mkakosya, Rajhab; Cheng, Jiye; Kau, Andrew L.; Rich, Stephen S.; Concannon, Patrick; Mychaleckyj, Josyf C.; Liu, Jie; Houpt, Eric; Li, Jia V.; Holmes, Elaine; Nicholson, Jeremy; Knights, Dan; Ursell, Luke K.; Knight, Rob; Gordon, Jeffrey I.
2013-01-01
Kwashiorkor, an enigmatic form of severe acute malnutrition, is the consequence of inadequate nutrient intake plus additional environmental insults. To investigate the role of the gut microbiome, we studied 317 Malawian twin pairs during the first 3 years of life. During this time, half of the twin pairs remained well-nourished, while 43% became discordant and 7% manifested concordance for acute malnutrition. Both children in twin pairs discordant for kwashiorkor were treated with a peanut-based, ready-to-use therapeutic food (RUTF). Time-series metagenomic studies revealed that RUTF produced a transient maturation of metabolic functions in kwashiorkor microbiomes that regressed when RUTF was stopped. Previously frozen fecal communities from several discordant pairs were each transplanted into gnotobiotic mice. The combination of Malawian diet and kwashiorkor microbiome produced marked weight loss in recipient mice, accompanied by perturbations in amino acid, carbohydrate and intermediary metabolism that were only transiently ameliorated with RUTF. These findings implicate the gut microbiome as a causal factor in kwashiorkor. PMID:23363771
Anisotropic Invariance and the Distribution of Quantum Correlations
NASA Astrophysics Data System (ADS)
Cheng, Shuming; Hall, Michael J. W.
2017-01-01
We report the discovery of two new invariants for three-qubit states which, similarly to the three-tangle, are invariant under local unitary transformations and permutations of the parties. These quantities have a direct interpretation in terms of the anisotropy of pairwise spin correlations. Applications include a universal ordering of pairwise quantum correlation measures for pure three-qubit states; trade-off relations for anisotropy, three-tangle and Bell nonlocality; strong monogamy relations for Bell inequalities, Einstein-Podolsky-Rosen steering inequalities, geometric discord and fidelity of remote state preparation (including results for arbitrary three-party states); and a statistical and reference-frame-independent form of quantum secret sharing.
Anisotropic Invariance and the Distribution of Quantum Correlations.
Cheng, Shuming; Hall, Michael J W
2017-01-06
We report the discovery of two new invariants for three-qubit states which, similarly to the three-tangle, are invariant under local unitary transformations and permutations of the parties. These quantities have a direct interpretation in terms of the anisotropy of pairwise spin correlations. Applications include a universal ordering of pairwise quantum correlation measures for pure three-qubit states; trade-off relations for anisotropy, three-tangle and Bell nonlocality; strong monogamy relations for Bell inequalities, Einstein-Podolsky-Rosen steering inequalities, geometric discord and fidelity of remote state preparation (including results for arbitrary three-party states); and a statistical and reference-frame-independent form of quantum secret sharing.
Recalled Explanations for Adolescent Girls' Engagement in Age-Discordant Sexual Relationships.
Cort, Natalie A; Senn, Theresa E; Carey, Michael P; Braksmajer, Amy
2016-06-01
Age-discordant sexual relationships are associated with negative sexual health outcomes for adolescent females. We were particularly interested in females' motivations for engaging in these relationships, and in contextual factors that increase receptivity to age-discordant relationships in the United States (U.S.). However, recent research addressing this topic in the U.S. has been sparse. To address this gap in the literature, we recruited 15 women (Mdn age = 26 years; 93 % African American) from an urban, publicly funded sexually transmitted disease clinic to qualitative interviews. Reasons given by women for their involvement in age-discordant sexual relationships as adolescents included: (a) desire for an actively engaged father figure, (b) to obtain material support, (c) to escape from a troubled home life, and (d) to express independence and maturity. Thus, familial, economic, and developmental factors motivate socioeconomically disadvantaged adolescent females to enter into age-discordant sexual relationships. Efforts to reduce females' participation in these relationships will need to address socioeconomic vulnerability and family relationships.
Experimental simulation of the Unruh effect on an NMR quantum simulator
NASA Astrophysics Data System (ADS)
Jin, FangZhou; Chen, HongWei; Rong, Xing; Zhou, Hui; Shi, MingJun; Zhang, Qi; Ju, ChenYong; Cai, YiFu; Luo, ShunLong; Peng, XinHua; Du, JiangFeng
2016-03-01
The Unruh effect is one of the most fundamental manifestations of the fact that the particle content of a field theory is observer dependent. However, there has been so far no experimental verification of this effect, as the associated temperatures lie far below any observable threshold. Recently, physical phenomena, which are of great experimental challenge, have been investigated by quantum simulations in various fields. Here we perform a proof-of-principle simulation of the evolution of fermionic modes under the Unruh effect with a nuclear magnetic resonance (NMR) quantum simulator. By the quantum simulator, we experimentally demonstrate the behavior of Unruh temperature with acceleration, and we further investigate the quantum correlations quantified by quantum discord between two fermionic modes as seen by two relatively accelerated observers. It is shown that the quantum correlations can be created by the Unruh effect from the classically correlated states. Our work may provide a promising way to explore the quantum physics of accelerated systems.
Quantum correlation properties in Matrix Product States of finite-number spin rings
NASA Astrophysics Data System (ADS)
Zhu, Jing-Min; He, Qi-Kai
2018-02-01
The organization and structure of quantum correlation (QC) of quantum spin-chains are very rich and complex. Hence the depiction and measures about the QC of finite-number spin rings deserved to be investigated intensively by using Matrix Product States(MPSs) in addition to the case with infinite-number. Here the dependencies of the geometric quantum discord(GQD) of two spin blocks on the total spin number, the spacing spin number and the environment parameter are presented in detail. We also compare the GQD with the total correlation(TC) and the classical correlation(CC) and illustrate its characteristics. Predictably, our findings may provide the potential of designing the optimal QC experimental detection proposals and pave the way for the designation of optimal quantum information processing schemes.
Cruz, C.; Soares-Pinto, D. O.; Brandão, P.; ...
2016-03-07
The control of quantum correlations in solid-state systems by means of material engineering is a broad avenue to be explored, since it makes possible steps toward the limits of quantum mechanics and the design of novel materials with applications on emerging quantum technologies. This letter explores the potential of molecular magnets to be prototypes of materials for quantum information technology in this context. More precisely, we engineered a material and from its geometric quantum discord we found significant quantum correlations up to 9540 K (even without entanglement); and, a pure singlet state occupied up to around 80 K (above liquidmore » nitrogen temperature), additionally. Our results could only be achieved due to the carboxylate group promoting a metal-to-metal huge magnetic interaction.« less
Robust thermal quantum correlation and quantum phase transition of spin system on fractal lattices
NASA Astrophysics Data System (ADS)
Xu, Yu-Liang; Zhang, Xin; Liu, Zhong-Qiang; Kong, Xiang-Mu; Ren, Ting-Qi
2014-06-01
We investigate the quantum correlation measured by quantum discord (QD) for thermalized ferromagnetic Heisenberg spin systems in one-dimensional chains and on fractal lattices using the decimation renormalization group approach. It is found that the QD between two non-nearest-neighbor end spins exhibits some interesting behaviors which depend on the anisotropic parameter Δ, the temperature T, and the size of system L. With increasing Δ continuously, the QD possesses a cuspate change at Δ = 0 which is a critical point of quantum phase transition (QPT). There presents the "regrowth" tendency of QD with increasing T at Δ < 0, in contrast to the "growth" of QD at Δ > 0. As the size of the system L becomes large, there still exists considerable thermal QD between long-distance end sites in spin chains and on the fractal lattices even at unentangled states, and the long-distance QD can spotlight the presence of QPT. The robustness of QD on the diamond-type hierarchical lattices is stronger than that in spin chains and Koch curves, which indicates that the fractal can affect the behaviors of quantum correlation.
Deciphering the origin of mito-nuclear discordance in two sibling caddisfly species.
Weigand, Hannah; Weiss, Martina; Cai, Huimin; Li, Yongping; Yu, Lili; Zhang, Christine; Leese, Florian
2017-10-01
An increasing number of phylogenetic studies have reported discordances among nuclear and mitochondrial markers. These discrepancies are highly relevant to widely used biodiversity assessment approaches, such as DNA barcoding, that rely almost exclusively on mitochondrial markers. Although the theoretical causes of mito-nuclear discordances are well understood, it is often extremely challenging to determine the principal underlying factor in a given study system. In this study, we uncovered significant mito-nuclear discordances in a pair of sibling caddisfly species. Application of genome sequencing, ddRAD and DNA barcoding revealed ongoing hybridization, as well as historical hybridization in Pleistocene refugia, leading us to identify introgression as the ultimate cause of the observed discordance pattern. Our novel genomic data, the discovery of a European-wide hybrid zone and the availability of established techniques for laboratory breeding make this species pair an ideal model system for studying species boundaries with ongoing gene flow. © 2017 John Wiley & Sons Ltd.
Quantum Phase Transitions in Conventional Matrix Product Systems
NASA Astrophysics Data System (ADS)
Zhu, Jing-Min; Huang, Fei; Chang, Yan
2017-02-01
For matrix product states(MPSs) of one-dimensional spin-1/2 chains, we investigate a new kind of conventional quantum phase transition(QPT). We find that the system has two different ferromagnetic phases; on the line of the two ferromagnetic phases coexisting equally, the system in the thermodynamic limit is in an isolated mediate-coupling state described by a paramagnetic state and is in the same state as the renormalization group fixed point state, the expectation values of the physical quantities are discontinuous, and any two spin blocks of the system have the same geometry quantum discord(GQD) within the range of open interval (0,0.25) and the same classical correlation(CC) within the range of open interval (0,0.75) compared to any phase having no any kind of correlation. We not only realize the control of QPTs but also realize the control of quantum correlation of quantum many-body systems on the critical line by adjusting the environment parameters, which may have potential application in quantum information fields and is helpful to comprehensively and deeply understand the quantum correlation, and the organization and structure of quantum correlation especially for long-range quantum correlation of quantum many-body systems.
Desthieux, Carole; Hermet, Aurore; Granger, Benjamin; Fautrel, Bruno; Gossec, Laure
2016-12-01
The integration of the patient in therapeutic decision-making is important in the management of rheumatoid arthritis (RA), but the patient opinion regarding disease status may differ from the physician's opinion. The aim of this study was to assess in the published literature the frequency and drivers of patient-physician discordance in global assessment in RA. A systematic literature review of all articles published up to January 2015 in Medline or Embase, reporting discordance in RA, was conducted by 2 investigators. Discordance was defined based on the absolute difference of patient global (PGA) and physician global assessments (PhGA) on 0-10-cm scales. The frequency of discordance and its predictors were collected in each study. Frequencies of discordance were pooled by meta-analysis using random effect. In all, 12 studies were selected (i.e., 11,879 patients): weighted mean ± SD age was 55.1 ± 13.9 years, weighted mean ± SD disease duration was 10.4 ± 9.3 years, and 80.7% were women. The value of the difference |PGA - PhGA| defining discordance varied between ≥0.5 cm (n = 2 studies) to ≥3 cm (n = 5 studies); the weighted mean value was 2.7 cm. The pooled percentage of patients with discordance was 43% (95% confidence interval 36%-51%; range 25%-76%). PGA was usually higher than PhGA. The drivers of PGA were pain and functional incapacity, whereas drivers of PhGA were joint counts and acute-phase reactants. Discordance in global assessment was most frequently defined as a difference of 3 points or more; even with such a stringent definition, up to half the patients were found to be discordant. The long-term consequences of this discordance remain to be determined. © 2016, American College of Rheumatology.
Family Discord, Parental Depression, and Psychopathology in Offspring: 20-Year Follow-up
ERIC Educational Resources Information Center
Pilowsky, Daniel J.; Wickramaratne, Priya; Nomura, Yoko; Weissman, Myrna M.
2006-01-01
Objective: To determine the independent effects of parental depression and family discord on offspring psychopathology among children at high and low risk of depression. Method: Family discord factors were assessed when subjects were approximately 17 years old, and offspring diagnoses were assessed about 20 years later. Parental and offspring…
Kayigamba, Felix R.; Franke, Molly F.; Bakker, Mirjam I.; Rodriguez, Carly A.; Bagiruwigize, Emmanuel; Wit, Ferdinand WNM; Rich, Michael L.; Schim van der Loeff, Maarten F.
2016-01-01
Introduction Some antiretroviral therapy naïve patients starting combination antiretroviral therapy (cART) experience a limited CD4 count rise despite virological suppression, or vice versa. We assessed the prevalence and determinants of discordant treatment responses in a Rwandan cohort. Methods A discordant immunological cART response was defined as an increase of <100 CD4 cells/mm3 at 12 months compared to baseline despite virological suppression (viral load [VL] <40 copies/mL). A discordant virological cART response was defined as detectable VL at 12 months with an increase in CD4 count ≥100 cells/mm3. The prevalence of, and independent predictors for these two types of discordant responses were analysed in two cohorts nested in a 12-month prospective study of cART-naïve HIV patients treated at nine rural health facilities in two regions in Rwanda. Results Among 382 patients with an undetectable VL at 12 months, 112 (29%) had a CD4 rise of <100 cells/mm3. Age ≥35 years and longer travel to the clinic were independent determinants of an immunological discordant response, but sex, baseline CD4 count, body mass index and WHO HIV clinical stage were not. Among 326 patients with a CD4 rise of ≥100 cells/mm3, 56 (17%) had a detectable viral load at 12 months. Male sex was associated with a virological discordant treatment response (P = 0.05), but age, baseline CD4 count, BMI, WHO HIV clinical stage, and travel time to the clinic were not. Conclusions Discordant treatment responses were common in cART-naïve HIV patients in Rwanda. Small CD4 increases could be misinterpreted as a (virological) treatment failure and lead to unnecessary treatment changes. PMID:27438000
Smolen, Josef S; Strand, Vibeke; Koenig, Andrew S; Szumski, Annette; Kotak, Sameer; Jones, Thomas V
2016-05-21
Discordance between patient and physician ratings of rheumatoid arthritis (RA) severity occurs in clinical practice and correlates with pain scores and measurements of joint disease. However, information is lacking on whether discordance impacts patients' ability to work. We evaluated the discordance between patient and physician ratings of RA disease activity before and after treatment with etanercept and investigated the associations between discordance, clinical outcomes, and work productivity. In the PRESERVE clinical trial, patients with moderate RA received open-label etanercept 50 mg once weekly plus methotrexate for 36 weeks. Baseline and week-36 disease characteristics and clinical and work productivity outcomes were categorized according to week-36 concordance category, defined as positive discordance (patient global assessment - physician global assessment ≥2), negative discordance (patient global assessment - physician global assessment ≤ -2), and concordance (absolute difference between the two disease activity assessments = 0 or 1). Correlations between discordance, clinical outcomes, and predictors of discordance were determined. At baseline, 520/762 (68.2 %) patient and physician global assessment scores were concordant, 194 (25.5 %) were positively discordant, and 48 (6.3 %) were negatively discordant. After 36 weeks of therapy, 556/763 (72.9 %) scores were concordant, 189 (24.8 %) were positively discordant, and 18 (2.4 %) were negatively discordant. Patients with week-36 concordance had the best 36-week clinical and patient-reported outcomes, and overall, the greatest improvement between baseline and week 36. Baseline pain, swollen joint count, duration of morning stiffness, fatigue, and patient general health significantly correlated with week-36 discordance, p < 0.0001 to p < 0.05. Additionally, baseline pain, patient general health, and C-reactive protein were predictors of week-36 discordance (odds ratios 1.22, 1
Quantum correlation dynamics in photosynthetic processes assisted by molecular vibrations
DOE Office of Scientific and Technical Information (OSTI.GOV)
Giorgi, G.L., E-mail: g.giorgi@inrim.it; Roncaglia, M.; Raffa, F.A.
2015-10-15
During the long course of evolution, nature has learnt how to exploit quantum effects. In fact, recent experiments reveal the existence of quantum processes whose coherence extends over unexpectedly long time and space ranges. In particular, photosynthetic processes in light-harvesting complexes display a typical oscillatory dynamics ascribed to quantum coherence. Here, we consider the simple model where a dimer made of two chromophores is strongly coupled with a quasi-resonant vibrational mode. We observe the occurrence of wide oscillations of genuine quantum correlations, between electronic excitations and the environment, represented by vibrational bosonic modes. Such a quantum dynamics has been unveiledmore » through the calculation of the negativity of entanglement and the discord, indicators widely used in quantum information for quantifying the resources needed to realize quantum technologies. We also discuss the possibility of approximating additional weakly-coupled off-resonant vibrational modes, simulating the disturbances induced by the rest of the environment, by a single vibrational mode. Within this approximation, one can show that the off-resonant bath behaves like a classical source of noise.« less
Quantum correlations in non-inertial cavity systems
DOE Office of Scientific and Technical Information (OSTI.GOV)
Harsij, Zeynab, E-mail: z.harsij@ph.iut.ac.ir; Mirza, Behrouz, E-mail: b.mirza@cc.iut.ac.ir
2016-10-15
Non-inertial cavities are utilized to store and send Quantum Information between mode pairs. A two-cavity system is considered where one is inertial and the other accelerated in a finite time. Maclaurian series are applied to expand the related Bogoliubov coefficients and the problem is treated perturbatively. It is shown that Quantum Discord, which is a measure of quantumness of correlations, is degraded periodically. This is almost in agreement with previous results reached in accelerated systems where increment of acceleration decreases the degree of quantum correlations. As another finding of the study, it is explicitly shown that degradation of Quantum Discordmore » disappears when the state is in a single cavity which is accelerated for a finite time. This feature makes accelerating cavities useful instruments in Quantum Information Theory. - Highlights: • Non-inertial cavities are utilized to store and send information in Quantum Information Theory. • Cavities include boundary conditions which will protect the entanglement once it has been created. • The problem is treated perturbatively and the maclaurian series are applied to expand the related Bogoliubov coefficients. • When two cavities are considered degradation in the degree of quantum correlation happens and it appears periodically. • The interesting issue is when a single cavity is studied and the degradation in quantum correlations disappears.« less
The Taxometrics of Marriage: Is Marital Discord Categorical?
Beach, Steven R. H.; Amir, Nader; Fincham, Frank D.; Leonard, Kenneth E.
2014-01-01
This study used taxometric methods to investigate the latent structure of the construct of marital adjustment as indexed by the Marital Adjustment Test (MAT; H. J. Locke & K. M. Wallace, 1959). That is, the authors examined whether marital adjustment is best thought of as a “dimension” of adjustment only or whether there also are categorical differences between “discordant” and “nondiscordant” couples. Analyses of data provided by 447 couples married for approximately 2 years provided converging evidence for a latent category of marital discord, suggesting that marital discord can be viewed as a qualitatively distinct state experienced by approximately 20% of the couples in the current sample. Implications for marital assessment are outlined. PMID:15982105
Kairania, Robert M.; Gray, Ronald H.; Kiwanuka, Noah; Makumbi, Fredrick; Sewankambo, Nelson K.; Serwadda, David; Nalugoda, Fred; Kigozi, Godfrey; Semanda, John; Wawer, Maria J.
2010-01-01
Disclosure of HIV seropositive results among HIV-discordant couples in sub-Saharan Africa is generally low. We describe a facilitated couple counselling approach to enhance disclosure among HIV-discordant couples. Using unique identifiers, 293 HIV-discordant couples were identified through retrospective linkage of married or cohabiting consenting adults individually enrolled into a cohort study and into two randomized trials of male circumcision in Rakai, Uganda. HIV discordant couples and a random sample of HIV-infected concordant and HIV-negative concordant couples (to mask HIV status) were invited to sensitization meetings to discuss the benefits of disclosure and couple counselling. HIV-infected partners were subsequently contacted to encourage HIV disclosure to their HIV uninfected partners. If the index positive partner agreed, the counsellor facilitated the disclosure of HIV results, and provided ongoing support. The proportion of disclosure was determined. 81% of HIV-positive partners in discordant relationships disclosed their status to their HIV-uninfected partners in the presence of the counsellor. The rates of disclosure were 81.3% in male HIV-positive and 80.2% in female HIV-positive discordant couples. Disclosure did not vary by age, education or occupation. In summary, disclosure of HIV-positive results in discordant couples using facilitated couple counselling approach is high, but requires a stepwise process of sensitization and agreement by the infected partner. PMID:20824557
Gut DNA viromes of Malawian twins discordant for severe acute malnutrition
Reyes, Alejandro; Blanton, Laura V.; Cao, Song; Zhao, Guoyan; Manary, Mark; Trehan, Indi; Smith, Michelle I.; Wang, David; Virgin, Herbert W.; Rohwer, Forest; Gordon, Jeffrey I.
2015-01-01
The bacterial component of the human gut microbiota undergoes a definable program of postnatal development. Evidence is accumulating that this program is disrupted in children with severe acute malnutrition (SAM) and that their persistent gut microbiota immaturity, which is not durably repaired with current ready-to-use therapeutic food (RUTF) interventions, is causally related to disease pathogenesis. To further characterize gut microbial community development in healthy versus malnourished infants/children, we performed a time-series metagenomic study of DNA isolated from virus-like particles (VLPs) recovered from fecal samples collected during the first 30 mo of postnatal life from eight pairs of mono- and dizygotic Malawian twins concordant for healthy growth and 12 twin pairs discordant for SAM. Both members of discordant pairs were sampled just before, during, and after treatment with a peanut-based RUTF. Using Random Forests and a dataset of 17,676 viral contigs assembled from shotgun sequencing reads of VLP DNAs, we identified viruses that distinguish different stages in the assembly of the gut microbiota in the concordant healthy twin pairs. This developmental program is impaired in both members of SAM discordant pairs and not repaired with RUTF. Phage plus members of the Anelloviridae and Circoviridae families of eukaryotic viruses discriminate discordant from concordant healthy pairs. These results disclose that apparently healthy cotwins in discordant pairs have viromes associated with, although not necessarily mediators, of SAM; as such, they provide a human model for delineating normal versus perturbed postnatal acquisition and retention of the gut microbiota’s viral component in populations at risk for malnutrition. PMID:26351661
Quantum correlations in chiral graphene nanoribbons.
Tan, Xiao-Dong; Koop, Cornelie; Liao, Xiao-Ping; Sun, Litao
2016-11-02
We compute the entanglement and the quantum discord (QD) between two edge spins in chiral graphene nanoribbons (CGNRs) thermalized with a reservoir at temperature T (canonical ensemble). We show that the entanglement only exists in inter-edge coupled spin pairs, and there is no entanglement between any two spins at the same ribbon edge. By contrast, almost all edge spin pairs can hold non-zero QD, which strongly depends on the ribbon width and the Coulomb repulsion among electrons. More intriguingly, the dominant entanglement always occurs in the pair of nearest abreast spins across the ribbon, and even at room temperature this type of entanglement is still very robust, especially for narrow CGNRs with the weak Coulomb repulsion. These remarkable properties make CGNRs very promising for possible applications in spin-quantum devices.
Time Series Discord Detection in Medical Data using a Parallel Relational Database [PowerPoint
DOE Office of Scientific and Technical Information (OSTI.GOV)
Woodbridge, Diane; Wilson, Andrew T.; Rintoul, Mark Daniel
Recent advances in sensor technology have made continuous real-time health monitoring available in both hospital and non-hospital settings. Since data collected from high frequency medical sensors includes a huge amount of data, storing and processing continuous medical data is an emerging big data area. Especially detecting anomaly in real time is important for patients’ emergency detection and prevention. A time series discord indicates a subsequence that has the maximum difference to the rest of the time series subsequences, meaning that it has abnormal or unusual data trends. In this study, we implemented two versions of time series discord detection algorithmsmore » on a high performance parallel database management system (DBMS) and applied them to 240 Hz waveform data collected from 9,723 patients. The initial brute force version of the discord detection algorithm takes each possible subsequence and calculates a distance to the nearest non-self match to find the biggest discords in time series. For the heuristic version of the algorithm, a combination of an array and a trie structure was applied to order time series data for enhancing time efficiency. The study results showed efficient data loading, decoding and discord searches in a large amount of data, benefiting from the time series discord detection algorithm and the architectural characteristics of the parallel DBMS including data compression, data pipe-lining, and task scheduling.« less
Desthieux, Carole; Molto, Anna; Granger, Benjamin; Saraux, Alain; Fautrel, Bruno; Gossec, Laure
2016-09-01
To assess patient-physician discordance in global assessment of disease activity in early axial spondyloarthritis (axSpA) over time and determinants of discordance. DESIR (Devenir des Spondyloarthropathies Indifférenciées Récentes) is a French, multicentre, longitudinal cohort of patients with early inflammatory back pain suggestive of axSpA. Patient global assessment (PGA) and physician global assessment (PhGA) were rated with a 0-10 numerical rating scale, every 6 months during 2 years then at 3 years. Discordance was defined by the absolute difference |PGA-PhGA|≥3 (range 0-10) and was analysed at each visit. Determinants of (PGA-PhGA) were assessed at the visit level by a generalised linear mixed model. A total of 702 patients were analysed at baseline (401 with complete data over 3 years): mean age 33.8±8.6 years, 379 (54.0%) female, mean symptom duration 18.1±10.5 months. Mean PGA values were always higher than mean PhGA values with a mean absolute difference of 1.8 points. At baseline, 202 (28.8%) patients had discordance mainly by PGA>PhGA; over 3 years the frequency of discordance was stable (range 25.5-28.8%). Discordance was not stable at the patient level, 118 (29.4%) patients were discordant once and 88 (22.0%) twice, and only 92 (22.9%) more than twice. Determinants of (PGA-PhGA) were spine pain (β=0.24, p<0.001) and fatigue (β=0.13, p<0.001). Discordance concerned a quarter of patients with early axSpA. Over 3 years of follow-up, discordance did not decrease (no 'reference shift'). Discordance was not a stable trait, indicating discordance is not a patient characteristic. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/
Maternal Concern about Child Weight in a Study of Weight-Discordant Siblings
Kral, Tanja V.E.; Moore, Reneé H.; Compher, Charlene W.
2014-01-01
Objective This study examined concern about child weight in mothers of weight-discordant siblings and determined the accuracy of maternal self-report versus measured child height, weight, and corresponding body mass index (BMI; kg/m2) z-score. Design Discordant-sibling design. Sample Forty-seven mothers of 5- to 12-year-old, weight-discordant siblings. Measurements Mothers self-reported their concern about child weight for each child separately and, for a subset of children, self-reported their heights and weights. Siblings’ height, weight, waist circumference, and adiposity were measured. Results The majority (83%) of mothers expressed concern about their overweight/obese child’s weight and 20% of mothers expressed concern about their normal-weight child’s weight (P<0.001). Difference scores in maternal concern about child weight were positively associated with difference scores in sibling BMI z-score (r=0.42; P=0.01) and percent body fat (r=0.56; P<0.001). For overweight/obese children only, maternal-reported child heights and weights were significantly lower compared to the measured values (P<0.03). Conclusions One fifth of mothers of weight-discordant siblings were unconcerned about their overweight/obese child’s weight and, for overweight/obese children only, mothers tended to under-report children’s height and weight. Mothers’ concern for their overweight/obese child’s weight was greater for sibling pairs who were more discordant in their weight. PMID:24612012
Maternal concern about child weight in a study of weight-discordant siblings.
Kral, Tanja V E; Moore, Reneé H; Compher, Charlene W
2015-01-01
This study examined concern about child weight in mothers of weight-discordant siblings and determined the accuracy of maternal self-report versus measured child height, weight, and corresponding body mass index (BMI; kg/m(2) ) z-score. Discordant sibling design. Forty-seven mothers of 5- to 12-year-old, weight-discordant siblings. Mothers self-reported their concern about child weight for each child separately and for a subset of children, self-reported their heights and weights. Siblings' height, weight, waist circumference, and adiposity were measured. The majority (83%) of mothers expressed concern about their overweight/obese child's weight and 20% of mothers expressed concern about their normal-weight child's weight (p < .001). Difference scores in maternal concern about child weight were positively associated with difference scores in sibling BMI z-score (r = 0.42; p = .01) and percent body fat (r = 0.56; p < .001). For overweight/obese children only, maternal-reported child heights and weights were significantly lower compared to the measured values (p < .03). One fifth of mothers of weight-discordant siblings were unconcerned about their overweight/obese child's weight and for overweight/obese children only, mothers tended to underreport children's height and weight. Mothers' concern for their overweight/obese child's weight was greater for sibling pairs who were more discordant in their weight. © 2014 Wiley Periodicals, Inc.
The double switch for atrioventricular discordance.
Brawn, William J
2005-01-01
Conventional surgery for atrioventricular discordance usually associated with ventricular arterial discordance leaves the morphologic right ventricle in the systemic circulation. Long-term follow-up results with this approach reveal a high incidence of right ventricular failure. The double switch procedure was introduced to restore the morphologic left ventricle to the systemic circulation. This operation is performed in two main ways: the atrial-arterial switch and the atrial switch plus Rastelli procedure. This double switch approach has been successful at least in the medium term in abolishing morphologic right ventricular failure and its associated tricuspid valve regurgitation. In the atrial-arterial switch group, there is an incidence of morphologic left ventricular dysfunction, sometimes associated with neoaortic valve regurgitation, and the minority of cases need aortic valve replacement. The long-term function of the morphologic left ventricle and the aortic valve need careful surveillance in the future. The atrial-Rastelli group of patients has not in the medium term shown evidence of ventricular dysfunction but will require change on a regular basis of their ventricular to pulmonary artery valved conduits.
Thermal quantum coherence and correlation in the extended XY spin chain
NASA Astrophysics Data System (ADS)
Sha, Ya-Ting; Wang, Yue; Sun, Zheng-Hang; Hou, Xi-Wen
2018-05-01
Quantum coherence and correlation of thermal states in the extended XY spin chain are studied in terms of the recently proposed l1 norm, skew information, and Bures distance of geometry discord (BGD), respectively. The entanglement measured via concurrence is calculated for reference. A two-dimensional susceptibility is introduced to explore their capability in highlighting the critical lines associated with quantum phase transitions in the model. It is shown that the susceptibility of the skew information and BGD is a genuine indicator of quantum phase transitions, and characterizes the factorization. However, the l1 norm is trivial for the factorization. An explicit scaling law of BGD is captured at low temperature in the XY model. In contrast to the entanglement, quantum coherence reveals a kind of long-range nonclassical correlation. Moreover, the obvious relation among model parameters is extracted for the factorized line in the extended model. Those are instructive for the understanding of quantum coherence and correlation in the theory of quantum information, and quantum phase transitions and factorization in condensed-matter physics.
Discordant Dry Eye Disease (An American Ophthalmological Society Thesis).
Shtein, Roni M; Harper, Daniel E; Pallazola, Vincent; Harte, Steven E; Hussain, Munira; Sugar, Alan; Williams, David A; Clauw, Daniel J
2016-08-01
To improve understanding of dry eye disease and highlight a subgroup of patients who have a component of central sensitization and neuropathic pain contributing to their condition. Prospective, cross-sectional, IRB-approved study comparing isolated dry eye disease (n=48) to fibromyalgia (positive control; n=23) and healthy (negative control; n=26) individuals with ocular surface examination, corneal confocal microscopy, quantitative sensory testing, and self-reported ocular symptoms and systemic associations. A subset of patients also underwent skin biopsy and/or brain neuroimaging. Dry eye patients were split into concordant (ie, those with dry eyes on examination) and discordant (ie, those with dry eye symptoms but normal examination) subgroups for further analysis. We hypothesized that on the systemic measures included, concordant patients would resemble healthy controls, whereas discordant patients would show evidence of centralized mechanisms similar to fibromyalgia. Schirmer test and Ocular Surface Disease Index (OSDI) scores indicated significant decreases in tear production (Schirmer: healthy, 18.5±8.2 mm; dry, 11.2±5.4 mm; fibromyalgia, 14.4±7.5; P <.001) and increases in self-reported dry eye symptoms (OSDI: healthy, 1.9±3.0; dry, 20.3±17.7; fibromyalgia, 20.3±17.1; P <.001) in the dry eye and fibromyalgia patients, compared to controls. The discordant subgroup had decreased corneal nerve density and decreased visual quality-of-life scores, similar to patients with fibromyalgia. Concordant patients were more similar to healthy controls on these measures. Individuals with discordant dry eye may have a central pathophysiologic mechanism leading to their eye pain symptoms, which could be an important factor to consider in treatment of chronic idiopathic dry eye.
Can the Catholic Church agree to condom use by HIV-discordant couples?
Bovens, L
2009-12-01
Does the position of the Roman Catholic Church on contraception also imply that the usage of condoms by HIV-discordant couples is illicit? A standard argument is to appeal to the doctrine of double effect to condone such usage, but this meets with the objection that there exists an alternative action that brings about the good effect-namely, abstinence. I argue against this objection, because an HIV-discordant couple does not bring about any bad outcome through condom usage-there is no disrespect displayed for the generative function of sex. One might retort that the badness of condom usage consists in thwarting the unitive function of sex. I argue that also this objection cannot be upheld. In conclusion, if there are no in-principle objections against condom usage for HIV-discordant couples, then policies that deny access to condoms to such couples are indefensible. HIV-discordant couples have a right to continue consummating their marriage in a manner that is minimally risky and this right cannot be trumped by utilitarian concerns that the distribution of condoms might increase promiscuity and along with it the HIV infection rate.
USDA-ARS?s Scientific Manuscript database
We describe new methods for characterizing gene tree discordance in phylogenomic datasets, which screen for deviations from neutral expectations, summarize variation in statistical support among gene trees, and allow comparison of the patterns of discordance induced by various analysis choices. Usin...
Venneman, Sandy; Leuchter, Andrew; Bartzokis, George; Beckson, Mace; Simon, Sara L; Schaefer, Melodie; Rawson, Richard; Newton, Tom; Cook, Ian A; Uijtdehaage, Sebastian; Ling, Walter
2006-01-01
Cocaine treatment trials suffer from a high rate of attrition. We examined pretreatment neurophysiological factors to identify participants at greatest risk. Twenty-five participants were divided into concordant and discordant groups following electroencephalogram (EEG) measures recorded prior to a double-blind, placebo-controlled treatment trial. Three possible outcomes were examined: successful completion, dropout, and removal. Concordant (high perfusion correlate) participants had an 85% rate of successful completion, while discordant participants had a 15% rate of successful completion. Twenty-five percent of dropouts and 50% of participants removed were discordant (low perfusion correlate), while only 25% of those who completed were discordant. Failure to complete the trial was not explained by depression, craving, benzoylecgonine levels or quantitative electroencephalogram (QEEG) power; thus cordance may help identify attrition risk.
Investigations of the Quantum Correlation in Two-Qubit Heisenberg XYZ Model with Decoherence
NASA Astrophysics Data System (ADS)
Guo-Hui, Yang
2017-03-01
Quantum correlation dynamics in an anisotropic Heisenberg XYZ model under decoherence is investigated with the use of concurrence C and quantum discord (QD). With the Werner state as the initial state, we discuss the influence of mixture degree r on the dynamics. There are some difference between the time evolution behaviors of these two correlation measures with different value of r. For 0 ≤ r ≤ 1/3, there exists quantum discord but no entanglement; For 1/3< r<1, there is a "entanglement sudden death and birth" phenomenon in the concurrence but not in the QD; For r=1, there is one interesting thing that the concurrence decays from 1 to a minimum value close to 0 but the QD vanish. In addition, we have investigated the influence of different parameters on the two correlation measures. It has been found that, the concurrence and QD both exhibit osillatory behaviors with the time evolution, which is independent on the magnetic field B and the coupling coefficient J z . However, the Dzyaloshinskii-Moriya interaction (D) and coupling coefficient J have strong influence on concurrence and QD. With the increasing of the D or J, the frequency of the oscillation getting larger. When time is fixed, with the increasing of D or J, the concurrence and QD change periodically.
Discordant Dry Eye Disease (An American Ophthalmological Society Thesis)
Shtein, Roni M.; Harper, Daniel E.; Pallazola, Vincent; Harte, Steven E.; Hussain, Munira; Sugar, Alan; Williams, David A.; Clauw, Daniel J.
2016-01-01
Purpose To improve understanding of dry eye disease and highlight a subgroup of patients who have a component of central sensitization and neuropathic pain contributing to their condition. Methods Prospective, cross-sectional, IRB-approved study comparing isolated dry eye disease (n=48) to fibromyalgia (positive control; n=23) and healthy (negative control; n=26) individuals with ocular surface examination, corneal confocal microscopy, quantitative sensory testing, and self-reported ocular symptoms and systemic associations. A subset of patients also underwent skin biopsy and/or brain neuroimaging. Dry eye patients were split into concordant (ie, those with dry eyes on examination) and discordant (ie, those with dry eye symptoms but normal examination) subgroups for further analysis. We hypothesized that on the systemic measures included, concordant patients would resemble healthy controls, whereas discordant patients would show evidence of centralized mechanisms similar to fibromyalgia. Results Schirmer test and Ocular Surface Disease Index (OSDI) scores indicated significant decreases in tear production (Schirmer: healthy, 18.5±8.2 mm; dry, 11.2±5.4 mm; fibromyalgia, 14.4±7.5; P<.001) and increases in self-reported dry eye symptoms (OSDI: healthy, 1.9±3.0; dry, 20.3±17.7; fibromyalgia, 20.3±17.1; P<.001) in the dry eye and fibromyalgia patients, compared to controls. The discordant subgroup had decreased corneal nerve density and decreased visual quality-of-life scores, similar to patients with fibromyalgia. Concordant patients were more similar to healthy controls on these measures. Conclusions Individuals with discordant dry eye may have a central pathophysiologic mechanism leading to their eye pain symptoms, which could be an important factor to consider in treatment of chronic idiopathic dry eye. PMID:28050051
Quantum correlation in degenerate optical parametric oscillators with mutual injections
NASA Astrophysics Data System (ADS)
Takata, Kenta; Marandi, Alireza; Yamamoto, Yoshihisa
2015-10-01
We theoretically and numerically study the quantum dynamics of two degenerate optical parametric oscillators with mutual injections. The cavity mode in the optical coupling path between the two oscillator facets is explicitly considered. Stochastic equations for the oscillators and mutual injection path based on the positive P representation are derived. The system of two gradually pumped oscillators with out-of-phase mutual injections is simulated, and its quantum state is investigated. When the incoherent loss of the oscillators other than the mutual injections is small, the squeezed quadratic amplitudes p ̂ in the oscillators are positively correlated near the oscillation threshold. It indicates finite quantum correlation, estimated via Gaussian quantum discord, and the entanglement between the intracavity subharmonic fields. When the loss in the injection path is low, each oscillator around the phase transition point forms macroscopic superposition even under a small pump noise. It suggests that the squeezed field stored in the low-loss injection path weakens the decoherence in the oscillators.
Queirós, Alexandra; Blickstein, Isaac; Valdoleiros, Sandra; Felix, Nisa; Cohen, Alvaro; Simões, Teresinha
2017-08-01
To evaluate if inter-twin estimated fetal weight (EFW) differences at 21-24 weeks' scans predict birth weight discordance in monochorionic and dichorionic twins born at three gestational age periods. We counted the number of pairs with discordant EFWs (EFWs greater than the mean + 1SD; i.e. a difference above 12% in dichorionic and 21% in monochorionic twins) derived during a 21-24 weeks' scan as compared to actual discordant birth weight (>25%) in monochorionic and dichorionic pairs born at ≤32, 33-36 and >36 weeks. We studied 416 dichorionic and 244 monochorionic twins. The frequency of EFWs discordance at 21-24 weeks was the same for dichorionic and monochorionic twins but the total number of birth weight discordant pairs was significantly smaller among dichorionic twins (OR 0.2, 95% CI 0.1, 0.6). Generally, the positive predictive values for birth weight discordance by using the EFWs difference were quite poor, but always better in monochorionic than in dichorionic twins. Whereas the negative predictive value and hence the sensitivity for monochorionic twins was 100% irrespective of gestational age at birth, it was much lower in the dichorionic pairs. Concordant EFWs at 21-24 weeks exclude discordant birth weight in monochorionic twins whereas discordant EFWs are poor predictors of birth weight discordance especially in dichorionic twins irrespective when the twins were born.
Role-exit theory and marital discord following extended military deployment.
Gambardella, Lucille C
2008-07-01
The purpose of this study was to determine the effectiveness of applying role-exit theory concepts in the counseling of military couples experiencing marital discord following extended periods of deployment. Qualitative case-study methodology was utilized to assess, diagnose, and treat 10 military couples using a framework based on role-exit theory. Six couples self-reported improvement in the marital relationship following this counseling approach. Role-exit theory based counseling may benefit other couples who experience marital discord due to role issues. The clinical nurse specialist might consider this paradigm when working with couples in marital therapy.
Hsia, Renee Y; Dai, Mengtao; Wei, Ran; Sabbagh, Sarah; Mann, N Clay
2017-01-01
The location of a patient's residence is often used for emergency medical services (EMS) system planning. Our objective is to evaluate the association between patient residence and emergency incident zip codes for 911 calls. We used data from the 2013 National Emergency Medical Services Information System (NEMSIS) Public-Release Research Dataset. We studied all 911 calls with a valid complaint by dispatch, identifying zip codes for both the residence and incident locations (n=12,376,784). The primary outcomes were geographic and distance discordances between patient residence and incident zip codes. We used a multivariate logistic regression model to determine geographic discordance between residence and incident zip codes by dispatch complaint, age, and sex. We also measured distances between locations with geospatial processing. The overall proportion of geographic discordance for all 911 calls was 27.7% (95% confidence interval [CI] 27.7% to 27.8%) and the median distance discordance was 11.5 miles (95% CI 11.5 to 11.5 miles). Lower geographic discordance rates were found among patients aged 65 to 79 years (20.2%; 95% CI 20.1% to 20.2%) and 80 years and older (14.5%; 95% CI 14.5% to 14.6%). Motor vehicle crashes (63.5%; 95% CI 63.5% to 63.6%), industrial accidents (59.3%; 95% CI 58.0% to 60.6%), and mass casualty incidents (50.6%; 95% CI 49.6% to 51.5%) were more likely to occur outside a patient's residence zip code. Median network distance between home and incident zip centroid codes ranged from 8.6 to 23.5 miles. In NEMSIS, there was geographic discordance between patient residence zip code and call location zip code in slightly more than one quarter of EMS responses records. The geographic discordance rates between residence and incident zip codes were associated with dispatch complaints and age. Although a patient's residence might be a valid proxy for incident location for elderly patients, this relationship holds less true for other age groups and among
Degree of quantum correlation required to speed up a computation
NASA Astrophysics Data System (ADS)
Kay, Alastair
2015-12-01
The one-clean-qubit model of quantum computation (DQC1) efficiently implements a computational task that is not known to have a classical alternative. During the computation, there is never more than a small but finite amount of entanglement present, and it is typically vanishingly small in the system size. In this paper, we demonstrate that there is nothing unexpected hidden within the DQC1 model—Grover's search, when acting on a mixed state, provably exhibits a speedup over classical, with guarantees as to the presence of only vanishingly small amounts of quantum correlations (entanglement and quantum discord)—while arguing that this is not an artifact of the oracle-based construction. We also present some important refinements in the evaluation of how much entanglement may be present in the DQC1 and how the typical entanglement of the system must be evaluated.
Gericke, G S
1986-01-18
Results from monozygotic (MZ) and dizygotic (DZ) twin research are often used in an attempt to gain a clearer understanding of the 'nature v. nurture' dilemma. Discordance between MZ twins has been considered to be environmental, and greater concordance in MZ compared with DZ pairs to be genetic. Current genetic and teratological theories considerably complicate the interpretation of concordance and discordance of abnormalities. The high rate of discordant intra-uterine death recently demonstrated in twins may profoundly influence the value of epidemiological studies usually performed in later life. Furthermore, indirect zygosity estimations based on sex ratios in DZ twins may be flawed because it is now recognized that increasing numbers of conditions are genetically heterogeneous. Emphasis is laid on problems of interpretation of discordance and concordance for developmental abnormalities in twins, and some possible mechanisms for their induction are discussed. Basic genetic concepts relevant to the expression of abnormalities in twins are outlined.
Dravid, Ameet N; Natrajan, Kartik; Kulkarni, Milind M; Saraf, Chinmay K; Mahajan, Uma S; Kore, Sachin D; Rathod, Niranjan M; Mahajan, Umakant S; Wadia, Rustom S
2018-02-01
Aim of this study was to estimate the prevalence of cerebrospinal fluid (CSF)/Plasma HIV-1 RNA discordance in virologically suppressed individuals presenting with incident neurologic symptoms.In this retrospective cohort study conducted between March 1, 2009, and March 1, 2017, HIV-1 infected adults exposed to atleast 12 months of antiretroviral therapy (ART) and having plasma viral load (VL) <1000 copies/mL (virologically suppressed) were included. Among these, individuals presenting with neurologic symptoms during follow-up were assessed for CSF/Plasma HIV-1 RNA discordance by measuring HIV-1 RNA in collected plasma and CSF samples. CSF/plasma HIV-1 RNA discordance was defined as either detectable CSF HIV-1 RNA (VL > 20 copies/mL) with an undetectable plasma RNA (complete viral suppression, VL ≤20 copies/mL) or CSF HIV-1 RNA ≥ 0.5 log10 higher than plasma RNA when plasma VL was between 20 and 1000 copies/mL (low-level viremia, LLV).Out of 1584 virologically suppressed patients, 71 (4.4%) presented with incident neurologic symptoms. Twenty out of 71 (28.2%) patients were diagnosed with CSF/Plasma HIV-1 discordance. Median plasma and CSF VL in patients with discordance was 120 [interquartile range (IQR): <20 to 332.5] and 4250 (IQR: 2550.0- 9615.0) copies/mL, respectively. All 9 individuals in which CSF HIV-1 genotypic resistance testing was done showed mutations that would compromise efficacy of prescribed ART regimen. Prevalence of CSF/plasma HIV-1 RNA discordance was higher among neurologically symptomatic patients with plasma LLV as compared with those with complete viral suppression (70% vs 11.8%, P < .001). The risk of discordance was also greater in patients who received protease inhibitor (PI) containing ART (P < .001) and those on ART regimens with central nervous system (CNS) penetration effectiveness (CPE) value <6 (P = .006).CSF/plasma HIV-1 RNA discordance indicates replication of HIV-1 that has adapted to the CNS or has
Sudden transition and sudden change from open spin environments
DOE Office of Scientific and Technical Information (OSTI.GOV)
Hu, Zheng-Da; School of Science, Jiangnan University, Wuxi 214122; Xu, Jing-Bo, E-mail: xujb@zju.edu.cn
2014-11-15
We investigate the necessary conditions for the existence of sudden transition or sudden change phenomenon for appropriate initial states under dephasing. As illustrative examples, we study the behaviors of quantum correlation dynamics of two noninteracting qubits in independent and common open spin environments, respectively. For the independent environments case, we find that the quantum correlation dynamics is closely related to the Loschmidt echo and the dynamics exhibits a sudden transition from classical to quantum correlation decay. It is also shown that the sudden change phenomenon may occur for the common environment case and stationary quantum discord is found at themore » high temperature region of the environment. Finally, we investigate the quantum criticality of the open spin environment by exploring the probability distribution of the Loschmidt echo and the scaling transformation behavior of quantum discord, respectively. - Highlights: • Sudden transition or sudden change from open spin baths are studied. • Quantum discord is related to the Loschmidt echo in independent open spin baths. • Steady quantum discord is found in a common open spin bath. • The probability distribution of the Loschmidt echo is analyzed. • The scaling transformation behavior of quantum discord is displayed.« less
Allen, S.; Tice, J.; Van de Perre, P.; Serufilira, A.; Hudes, E.; Nsengumuremyi, F.; Bogaerts, J.; Lindan, C.; Hulley, S.
1992-01-01
OBJECTIVE--To determine whether HIV testing and counselling increased condom use and decreased heterosexual transmission of HIV in discordant couples. DESIGN--Prospective study. SETTING--Kigali, the capital of Rwanda. SUBJECTS--Cohabiting couples with discordant HIV serology results. MAIN OUTCOME MEASURES--Condom use in the couple and HIV seroconversion in the negative partners. RESULTS--60 HIV discordant couples were identified, of whom 53 were followed for an average of 2.2 years. The proportion of discordant couples using condoms increased from 4% to 57% after one year of follow up. During follow up two of the 23 HIV negative men and six of the 30 HIV negative women seroconverted (seroconversion rates of 4 and 9 per 100 person years). The rate among women was less than half that estimated for similar women in discordant couples whose partners had not been serotested. Condom use was less common among those who seroconverted (100% v 5%, p = 0.01 in men; 67% v 25%, p = 0.14 in women). CONCLUSIONS--Roughly one in seven cohabiting couples in Kigali have discordant HIV serological results. Confidential HIV serotesting with counselling caused a large increase in condom use and was associated with a lower rate of new HIV infections. HIV testing is a promising intervention for preventing the spread of HIV in African cities. PMID:1628088
Palamar, Joseph J.; Shearston, Jenni A.; Cleland, Charles M.
2016-01-01
Background Nonmedical opioid use has become a major public health concern due to increases in treatment admissions, overdoses, and deaths. Use has also been linked to heroin initiation. Reliable data on nonmedical opioid use is needed to continue to inform prevention. Objective To determine the prevalence and correlates of discordant self-reports of nonmedical use of opioids in a national sample. Methods Utilizing a nationally representative sample of 31,149 American high school seniors in the Monitoring the Future study (2009–2013), discordant responses between self-reported 12-month nonmedical opioid use and self-reported 12-month nonmedical Vicodin and OxyContin use (reporting Vicodin/OxyContin use, but not reporting “opioid” use) were assessed. We also determined characteristics of students who were most likely to provide a discordant response. Results 37.1% of those reporting nonmedical Vicodin use and 28.2% of those reporting nonmedical OxyContin use did not report overall nonmedical opioid use. Prevalence of nonmedical opioid use (8.3%) would increase when factoring in Vicodin, OxyContin, or both, by 2.8%, 1.3%, and 3.3%, respectively. Females were more likely to provide a discordant response for Vicodin and highly religious students were more likely to provide a discordant response regarding OxyContin use. Those who reported cocaine or nonmedical tranquilizer use were at consistently low odds for discordant responses. Nonmedical amphetamine users were at low odds for providing a discordant Vicodin response. Conclusion Prevalence of nonmedical opioid use may be underreported on some surveys, particularly among specific subpopulations. Further research on the affect of question order and skip-patterns (e.g., “gate” questions) is needed. PMID:27315427
Zwickl, Derrick J; Stein, Joshua C; Wing, Rod A; Ware, Doreen; Sanderson, Michael J
2014-09-01
We describe new methods for characterizing gene tree discordance in phylogenomic data sets, which screen for deviations from neutral expectations, summarize variation in statistical support among gene trees, and allow comparison of the patterns of discordance induced by various analysis choices. Using an exceptionally complete set of genome sequences for the short arm of chromosome 3 in Oryza (rice) species, we applied these methods to identify the causes and consequences of differing patterns of discordance in the sets of gene trees inferred using a panel of 20 distinct analysis pipelines. We found that discordance patterns were strongly affected by aspects of data selection, alignment, and alignment masking. Unusual patterns of discordance evident when using certain pipelines were reduced or eliminated by using alternative pipelines, suggesting that they were the product of methodological biases rather than evolutionary processes. In some cases, once such biases were eliminated, evolutionary processes such as introgression could be implicated. Additionally, patterns of gene tree discordance had significant downstream impacts on species tree inference. For example, inference from supermatrices was positively misleading when pipelines that led to biased gene trees were used. Several results may generalize to other data sets: we found that gene tree and species tree inference gave more reasonable results when intron sequence was included during sequence alignment and tree inference, the alignment software PRANK was used, and detectable "block-shift" alignment artifacts were removed. We discuss our findings in the context of well-established relationships in Oryza and continuing controversies regarding the domestication history of O. sativa. © The Author(s) 2014. Published by Oxford University Press, on behalf of the Society of Systematic Biologists. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
Adelson, Stewart L
2011-10-01
The American Academy of Child and Adolescent Psychiatry (AACAP) is preparing a publication, Practice Parameter on Gay, Lesbian or Bisexual Sexual Orientation, Gender-Nonconformity, and Gender Discordance in Children and Adolescents. This article discusses the development of the part of the parameter related to gender nonconformity and gender discordance and describes the practice parameter preparation process,rationale, key scientific evidence, and methodology. Also discussed are terminology considerations, related clinical issues and practice skills, and overall organization of information including influences on gender development, gender role behavior, gender nonconformity and gender discordance, and their relationship to the development of sexual orientation.
Grimm, Erin E; Schmidt, Rodney A; Swanson, Paul E; Dintzis, Suzanne M; Allison, Kimberly H
2010-08-01
We were interested in determining our concordance between fluorescence in situ hybridization (FISH) and a previously validated immunohistochemical HER2 assay to identify possible reasons for discordance and to determine if all reasons for discordance were addressed by the American Society of Clinical Oncology/College of American Pathologists guidelines. We reviewed 697 cases (2004-2007) in which HER2 immunohistochemical and FISH testing were concurrently done. Overall concordance between nonequivocal immunohistochemical and FISH results was 96%. Of the 19 discordant cases, 13 (68%) were interpreted as positive immunohistochemically but negative by FISH. The primary reason for this discordance was immunohistochemical interpretation. Weak stain intensity, granular staining, and interpretation in areas of crush artifact were identified as the most common issues. Of the 6 cases interpreted as immunohistochemically negative and FISH-positive, 2 were from patients known to be receiving trastuzumab at the time of biopsy, 1 was very close to the FISH equivocal category, and 4 cases had fewer than 1.5 CEP17 signals per cell (1 patient in this group was also receiving trastuzumab). Focusing on issues with HER2 immunohistochemical interpretation can improve concordance rates for immunohistochemically positive cases, but biologic reasons may explain some discordant immunohistochemically negative cases.
Cannabis Involvement and Nonsuicidal Self-Injury: A Discordant Twin Approach.
Few, Lauren R; Grant, Julia D; Nelson, Elliot C; Trull, Timothy J; Grucza, Richard A; Bucholz, Kathleen K; Verweij, Karin J H; Martin, Nicholas G; Statham, Dixie J; Madden, Pamela A F; Heath, Andrew C; Lynskey, Michael T; Agrawal, Arpana
2016-11-01
Cannabis use, particularly at an early age, has been linked to suicidal thoughts and behavior, but minimal work has examined the association between cannabis use and lifetime nonsuicidal self-injury (NSSI). The current study aims to characterize the overlap between lifetime and early cannabis use and NSSI and to examine genetic and environmental mechanisms of this association. Adult male and female twins from the Australian Twin Registry (N = 9,583) were used to examine the odds of NSSI associated with lifetime cannabis use and early cannabis use (i.e., <17 years of age). These associations were also examined within monozygotic (MZ) twins discordant for cannabis use and MZ twins discordant for early cannabis use. Analyses were replicated in an independent sample of female twins (n = 3,787) accounting for the age at onset of cannabis use and NSSI. Lifetime cannabis use (odds ratio [OR] = 2.84, 95% CI [2.23, 3.61]) and early cannabis use were associated with increased odds of NSSI (OR = 2.15, 95% CI [1.75, 2.65]), and this association remained when accounting for covariates. The association was only significant, however, in MZ twin pairs discordant for early cannabis use (OR = 3.20, 95% CI [1.17, 8.73]). Replication analyses accounting for the temporal ordering of cannabis use and NSSI yielded similar findings of nominal significance. Results suggest that NSSI is associated with cannabis involvement via differing mechanisms. For lifetime cannabis use, the lack of association in discordant pairs suggests the role of shared genes and family environment. However, in addition to such shared familial influences, person-specific and putatively causal factors contribute to the relationship between early cannabis use and NSSI. Therefore, delaying the onset of cannabis use may reduce exposure to influences that exacerbate vulnerabilities to NSSI.
The road not taken: life experiences in monozygotic twin pairs discordant for major depression
Kendler, KS; Halberstadt, LJ
2012-01-01
In an effort to understand how environmental experiences contribute to risk for major depression (MD), we conducted joint autobiographical interviews with 14 pairs of monozygotic twins (mean age 51.2) rigorously discordant for a lifetime history of MD. Twelve of the pairs could be sorted into four broad categories. In two pairs, discordance was associated with a single traumatic event occurring to the affected twin. In seven pairs, the well twin had one stable, long-term, successful romantic relationship, whereas the affected co-twin had romantic reversals one or more of which precipitated depressive episodes. These pairs varied in the degree to which the romantic problems seemed to arise from bad luck or poor choices. In one pair, occupational difficulties were strongly related to discordance in experiences with MD. In two pairs, several mechanisms seemed to be at work. Discordance in the quality of intimate love relationships was the most common etiological factor revealed by interview in these discordant pairs, with single dramatic events and occupational problems being considerably rarer. Even in this best of natural experiments, the causal interrelationship between personality, environment and depressive episodes was not always clear. Many pairs illustrated the protective effects of planfulness and the malignant effect of cumulative continuity where early difficulties in relationships shaped the subsequent life course. These results speak both to the importance of environmental influences on human well-being and psychopathology, and the complexity of the causal paths underlying their effects. PMID:22641178
Palamar, Joseph J; Shearston, Jenni A; Cleland, Charles M
2016-09-01
Nonmedical opioid use has become a major public health concern due to increases in treatment admissions, overdoses, and deaths. Use has also been linked to heroin initiation. Reliable data on nonmedical opioid use are needed to continue to inform prevention. To determine the prevalence and correlates of discordant self-report of nonmedical use of opioids in a national sample. Utilizing a nationally representative sample of 31,149 American high school seniors in the Monitoring the Future study (2009-2013), discordant responses between self-reported 12-month nonmedical opioid use and self-reported 12-month nonmedical Vicodin and OxyContin use (reporting Vicodin/OxyContin use, but not reporting "opioid" use) were assessed. We also used multivariable logistic regression to determine the characteristics of students who were most likely to provide a discordant response. 37.1% of those reporting nonmedical Vicodin use and 28.2% of those reporting nonmedical OxyContin use did not report overall nonmedical opioid use. Prevalence of nonmedical opioid use (8.3%) would increase when factoring in Vicodin, OxyContin, or both, by 2.8%, 1.3%, and 3.3%, respectively. Females were more likely to provide a discordant response to Vicodin and highly religious students were more likely to provide a discordant response regarding OxyContin use. Those who reported cocaine or nonmedical tranquilizer use were at consistently low odds for discordant responses. Nonmedical amphetamine users were at low odds for providing a discordant Vicodin response. Prevalence of nonmedical opioid use may be underreported on some surveys, particularly among specific subpopulations. Further research on the effect of question order and skip-patterns (e.g., "gate" questions) is needed. Reliable data on nonmedical opioid use are needed to continue to accurately inform prevention.
Brickell, Kiri L; Leverenz, James B; Steinbart, Ellen J; Rumbaugh, Malia; Schellenberg, Gerard D; Nochlin, David; Lampe, Thomas H; Holm, Ida E; Van Deerlin, Vivianna; Yuan, Wuxing; Bird, Thomas D
2007-01-01
Aim Neuropathological examination of both individuals in a monozygotic (MZ) twin pair with Alzheimer's disease (AD) is rare, especially in the molecular genetic era. We had the opportunity to assess the concordance and discordance of clinical presentation and neuropathology in three MZ twin pairs with AD. Methods The MZ twins were identified and characterised by the University of Washington Alzheimer's Disease Research Center. We reviewed the available clinical and neuropathological records for all six cases looking specifically for concordance and discordance of clinical phenotype, neuritic amyloid plaques (NP), neurofibrillary tangles (NFT) and Lewy related pathology (LRP). Results Discordance in age of onset for developing AD in the MZ twins varied from 4 to 18 years. Clinical presentations also differed between twins. One twin presented with a dementia with Lewy Body clinical syndrome while the other presented with typical clinical AD. Neuropathology within the MZ twin pairs was concordant for NP and NFT, regardless of duration of disease, and was discordant for LRP. This difference was most marked in the late onset AD twin pair. One pair was found to have a mutation in presenilin‐1 (PS1) (A79V) with remarkably late onset in a family member. Conclusions MZ twins with AD can vary considerably in age of onset, presentation and disease duration. The concordance of NP and NFT pathological change and the discordance of LRP support the concept that, in AD, the former are primarily under genetic control whereas the latter (LRP) is more influenced by disease duration and environmental factors. The A79V mutation in PS1 can be associated with very late onset of dementia. PMID:17615170
Xiao, Yanni; Shen, Minxue; Ma, Shujuan; Tao, Xuan; Wen, Shi Wu; Tan, Hongzhuan
2018-06-01
To assess the effect of weight gain during pregnancy on intertwin delivery weight discordance. In the present retrospective cohort study using twin delivery records, data were extracted from the 2011-2015 USA birth registration dataset created by the Centers for Disease Control and Prevention. The outcome variable was delivery weight discordance. The nonlinear association of weight gain during pregnancy with delivery weight discordance was examined using a generalized additive model, adjusting for potential confounders. A total of 255 627 twin pairs were included in this analysis. Weight gain during pregnancy showed an inverse, yet nonlinear, association with intertwin delivery weight discordance. Women with weight gain of approximately 25 kg exhibited the lowest level of discordance. When stratified by pre-pregnancy body mass index, the association of weight gain with discordance became insignificant among obese women. When categorizing weight gain according to recommendations from the Institute of Medicine, inadequate weight gain was associated with increased risk of discordance among women of any pre-pregnancy body mass index. Twin pregnancies with maternal weight gain of approximately 25 kg demonstrated the lowest risk of developing intertwin delivery weight discordance, while inadequate weight gain was a risk factor for delivery weight discordance in all pre-pregnancy body mass index categories. © 2018 International Federation of Gynecology and Obstetrics.
McCune-Albright syndrome in a discordant monozygotic twin.
Peleg, Roni; Luba, Avizov; Eliakim, Alon; Israeli-Shani, Lilach; Manor, Esther; Birk, Ruth; Parvari, Ruti
2009-06-01
McCune-Albright syndrome is a sporadic disorder characterized by polystotic fibrous dysplasia, pigmented patches of skin, and endocrinological abnormalities. To compare the genetic characteristics of the GNAS1 gene in a monozygotic pair of twins, one of whom was diagnosed with MAS while the other had no indication of the syndrome. We performed a molecular analysis of the GNAS1 gene in DNA extracted from peripheral blood cells and quantification of mRNA extracted from lymphoblastoid cells from both twins by quantitative real-time polymerase chain reaction. Monozygosity of the twins was confirmed by typing them to four highly polymorphic microsatellites. Molecular analysis of the GNAS1 gene extracted from both twins did not reveal the cause of this discordance. It is possible that the exact molecular mechanism for the MAS discordance can only be determined by sampling affected tissues.
Interpreting quantum coherence through a quantum measurement process
NASA Astrophysics Data System (ADS)
Yao, Yao; Dong, G. H.; Xiao, Xing; Li, Mo; Sun, C. P.
2017-11-01
Recently, there has been a renewed interest in the quantification of coherence or other coherencelike concepts within the framework of quantum resource theory. However, rigorously defined or not, the notion of coherence or decoherence has already been used by the community for decades since the advent of quantum theory. Intuitively, the definitions of coherence and decoherence should be two sides of the same coin. Therefore, a natural question is raised: How can the conventional decoherence processes, such as the von Neumann-Lüders (projective) measurement postulation or partially dephasing channels, fit into the bigger picture of the recently established theoretical framework? Here we show that the state collapse rules of the von Neumann or Lüders-type measurements, as special cases of genuinely incoherent operations (GIOs), are consistent with the resource theories of quantum coherence. New hierarchical measures of coherence are proposed for the Lüders-type measurement and their relationship with measurement-dependent discord is addressed. Moreover, utilizing the fixed-point theory for C* algebra, we prove that GIOs indeed represent a particular type of partially dephasing (phase-damping) channels which have a matrix representation based on the Schur product. By virtue of the Stinespring dilation theorem, the physical realizations of incoherent operations are investigated in detail and we find that GIOs in fact constitute the core of strictly incoherent operations and generally incoherent operations and the unspeakable notion of coherence induced by GIOs can be transferred to the theories of speakable coherence by the corresponding permutation or relabeling operators.
Gausi, Blessings; Chagomerana, Maganizo B; Tang, Jennifer H; Haddad, Lisa B; Hosseinipour, Mina C; Tweya, Hannock; Phiri, Sam
2018-05-31
Some HIV sero-discordant couples are faced with the dual challenge of preventing HIV transmission to the uninfected partner and avoiding unintended pregnancy. Therefore, we hypothesized that sero-discordance is associated with dual method use at last sex. We analyzed data from a cross-sectional survey of HIV-infected men and women attending 2 ART clinics in Lilongwe, Malawi. We used Fisher's exact test and Wilcoxon rank sum to assess for associations between sero-discordance, covariates, and dual method use. Multivariable logistic regression was used to estimate the adjusted odds ratio (aOR) and 95% confidence intervals (CI) of dual method use at last sex, comparing sero-discordant to sero-concordant relationships. Separate analyses were conducted for men and women. We surveyed 253 HIV infected men, of which 44 (17.4%) were in a known sero-discordant relationship and 63 (24.9%) were utilizing dual methods at last sex. Likewise, among 302 HIV infected women surveyed, 57 (18.9%) were in a known sero-discordant relationship, and 80 (26.5%) were utilizing dual method at last sex. Sero-discordance was not significantly associated with dual method use at last sex for among HIV infected men (aOR = 0.62, 95% CI: 0.27-1.44) or women (aOR = 1.21, 95% CI: 0.59-2.47). Dual method use was low among all HIV-infected individuals, irrespective of their partner's HIV status. Given these findings, we recommend greater efforts to encourage HIV providers to counsel their patients about the importance of dual method use to prevent both unintended pregnancy and sexually transmitted infections.
Wang, Zilian; Luo, Yanmin; Sun, Hongyu; Zhou, Yi; Huang, Linhuan; Li, Manchao; Fang, Qun; Jiang, Shiwen
2012-01-01
Background The human endogenous retroviral family W, Env(C7), member 1 gene (HERVWE1) is thought to participate in trophoblast cell fusion, and its expression is diminished in the placentas of singleton intrauterine growth-retarded pregnancies. However, there is limited information about the role of HERVWE1 in discordant fetal growth in twins. This study was to compare HERVWE1 gene expression between the placentas of discordant monozygotic twins and to identify its regulation by methylation. Methodology/Principal Findings Fetuses from twenty-one pairs of monozygotic, dichorionic, discordant twins were marked as “smaller” or “larger” according to birth weight. Placental HERVWE1 mRNA and protein expression profiles were analyzed using quantitative RT-PCR and immunohistochemistry (IHC) staining. Methylation profiles of the HERVWE1 promoter region were analyzed using a pyrosequencing assay. DNA methyltransferase (DNMT) transcript levels were analyzed by RT-PCR. 5-methyl cytosine (5-MC) was stained using an immunohistochemical assay. There was a significant negative correlation between HERVWE1 mRNA levels and birth weight in twins (P<0.01). Whereas the mean methylation level of the HERVWE1 promoter region was diminished in the smaller group in discordant twins(P<0.01), increased mRNA and protein levels of HERVWE1 were found in smaller fetuses compared with larger fetuses in discordant twins(P<0.01). There was no significant difference in 5-MC staining intensity between discordant twins (P>0.05). The DNMT3b3 mRNA levels in the smaller group were significantly downregulated compared with the larger group in discordant twins(P<0.05), whereas the DNMT3b7 mRNA levels in the smaller group were significantly upregulated compared with the larger group in discordant twins(P<0.05). Conclusions/Significance In discordant, monozygotic, dichorionic twins, HERVWE1 expression was higher in smaller fetuses and lower in larger fetuses. Methylation of the HERVWE1 gene promoter
Two monozygotic twin pairs discordant for female-to-male transsexualism.
Segal, Nancy L
2006-06-01
Two monozygotic female twin pairs discordant for transsexualism are described. These reports double the number of such case studies in the current scientific literature. Interviews with the twins and their families indicated that unusual medical and life history factors did not play causal roles. However, inspection of medical records for one transsexual twin suggested that some early life experiences may have exacerbated tendencies toward male gender identification. In both pairs, the twins' gender identity differences emerged early, consistent with, but not proof of, co-twin differences in prenatal hormonal influences. The identification of additional discordant MZ female twin pairs can advance biological and psychological understanding of transsexualism. Suggestions for future research, based upon findings from these two twin pairs and from studies of female-to-male transsexuals, are provided.
Quantum Correlation in the XY Spin Model with Anisotropic Three-Site Interaction
NASA Astrophysics Data System (ADS)
Wang, Yao; Chai, Bing-Bing; Guo, Jin-Liang
2018-05-01
We investigate pairwise entanglement and quantum discord (QD) in the XY spin model with anisotropic three-site interaction at zero and finite temperatures. For both the nearest-neighbor spins and the next nearest-neighbor spins, special attention is paid to the dependence of entanglement and QD on the anisotropic parameter δ induced by the next nearest-neighbor spins. We show that the behavior of QD differs in many ways from entanglement under the influences of the anisotropic three-site interaction at finite temperatures. More important, comparing the effects of δ on the entanglement and QD, we find the anisotropic three-site interaction plays an important role in the quantum correlations at zero and finite temperatures. It is found that δ can strengthen the quantum correlation for both the nearest-neighbor spins and the next nearest-neighbor spins, especially for the nearest-neighbor spins at low temperature.
Liphart, Jodi; Gallichio, Joann; Tilson, Julie K; Pei, Qinglin; Wu, Samuel S; Duncan, Pamela W
2016-01-01
Objective To ascertain the existence of discordance between perceived and measured balance in persons with stroke and to examine the impact on walking speed and falls. Design A secondary analysis of a phase three, multicentered randomized controlled trial examining walking recovery following stroke. Subjects A total of 352 participants from the Locomotor Experience Applied Post-Stroke (LEAPS) trial. Methods Participants were categorized into four groups: two concordant and two discordant groups in relation to measured and perceived balance. Number and percentage of individuals with concordance and discordance were evaluated at two and 12 months. Walking speed and fall incidence between groups were examined. Main measures Perceived balance was measured by the Activity-specific Balance Confidence scale, measured balance was determined by the Berg Balance Scale and gait speed was measured by the 10-meter walk test. Results Discordance was present for 35.8% of participants at two months post-stroke with no statistically significant change in proportion at 12 months. Discordant participants with high perceived balance and low measured balance walked 0.09 m/s faster at two months than participants with concordant low perceived and measured balance (p < 0.05). Discordant participants with low perceived balance and high measured balance walked 0.15 m/s slower than those that were concordant with high perceived and measured balance (p ⩽ 0.0001) at 12 months. Concordant participants with high perceived and measured balance walked fastest and had fewer falls. Conclusions Discordance existed between perceived and measured balance in one-third of individuals at two and 12 months post-stroke. Perceived balance impacted gait speed but not fall incidence. PMID:25810426
Rispel, Laetitia C; Cloete, Allanise; Metcalf, Carol A
2015-01-01
In HIV-discordant relationships, the HIV-negative partner also carries the burden of a stigmatised disease. For this reason, couples often hide their HIV-discordant status from family, friends and community members. This perpetuates the silence around HIV-discordant relationships and impacts on targeted HIV prevention, treatment and counselling efforts. This article reports on experiences of stigma and discrimination among HIV-discordant couples in South Africa, Tanzania and Ukraine. During 2008, HIV-discordant couples who had been in a relationship for at least one year were recruited purposively through health-care providers and civil society organisations in the three countries. Participants completed a brief self-administered questionnaire, while semi-structured interviews were conducted with each partner separately and with both partners together. Interviews were analysed using thematic content analysis. Fifty-one couples were recruited: 26 from South Africa, 10 from Tanzania, and 15 from Ukraine. Although most participants had disclosed their HIV status to someone other than their partner, few were living openly with HIV discordance. Experiences of stigma were common and included being subjected to gossip, rumours and name-calling, and HIV-negative partners being labelled as HIV-positive. Perpetrators of discrimination included family members and health workers. Stigma and discrimination present unique and complex challenges to couples in HIV sero-discordant relationships in these three diverse countries. Addressing stigmatisation of HIV-discordant couples requires a holistic human rights approach and specific programme efforts to address discrimination in the health system.
Tairy, Daniel; Levy, Itzchak; Turner, Dan; Livnat, Yuval; Mor, Zohar
2018-06-01
HIV-discordant gay male couples may play an important role in HIV-transmissions. This cross-sectional study compared the knowledge, attitudes and sexual behaviors of HIV-uninfected gay men, between those in HIV-discordant and those in HIV-concordant steady relationships. Anonymous questionnaires were distributed electronically in designated gay-related internet sites and in AIDS-clinics in 2015. The dependent variable was defined as a steady relationship of an HIV-uninfected man with an HIV-infected partner. Risky sexual behavior was defined as unprotected anal intercourse (UAI) with a sex partner whose HIV-status was either positive or unknown. Of 2,319 responders, 460 (20%) were HIV-uninfected gay men in steady relationships, of whom 72 were in HIV-discordant relationships and 388 were in HIV-concordant relationships. Those in HIV-discordant relationships presented better established knowledge regarding HIV-transmission, more lenient attitudes regarding UAI, and reported being involved in riskier sexual behavior, both within and outside their steady relationship compared to men in HIV-concordant relationships. UAI was performed by 48% of the HIV-discordant couples and was associated with the use of sero-positioning strategy and with achieving undetectable viral-load. These findings reflect the complexity of constant use of condoms during long-term sero-discordant relationships. Targeted interventions for HIV-prevention in HIV-discordant couples should be employed for balancing the partners' desire for intimacy and sexual pleasure in the relationship, while reducing the risk for acquiring HIV. ART: Antiretroviral therapy; PEP: Post exposure prophylaxis; PrEP: Pre exposure prophylaxis; STI: Sexually transmitted infections; UAI: Unprotected anal intercourse.
Visual Bias Predicts Gait Adaptability in Novel Sensory Discordant Conditions
NASA Technical Reports Server (NTRS)
Brady, Rachel A.; Batson, Crystal D.; Peters, Brian T.; Mulavara, Ajitkumar P.; Bloomberg, Jacob J.
2010-01-01
We designed a gait training study that presented combinations of visual flow and support-surface manipulations to investigate the response of healthy adults to novel discordant sensorimotor conditions. We aimed to determine whether a relationship existed between subjects visual dependence and their postural stability and cognitive performance in a new discordant environment presented at the conclusion of training (Transfer Test). Our training system comprised a treadmill placed on a motion base facing a virtual visual scene that provided a variety of sensory challenges. Ten healthy adults completed 3 training sessions during which they walked on a treadmill at 1.1 m/s while receiving discordant support-surface and visual manipulations. At the first visit, in an analysis of normalized torso translation measured in a scene-movement-only condition, 3 of 10 subjects were classified as visually dependent. During the Transfer Test, all participants received a 2-minute novel exposure. In a combined measure of stride frequency and reaction time, the non-visually dependent subjects showed improved adaptation on the Transfer Test compared to their visually dependent counterparts. This finding suggests that individual differences in the ability to adapt to new sensorimotor conditions may be explained by individuals innate sensory biases. An accurate preflight assessment of crewmembers biases for visual dependence could be used to predict their propensities to adapt to novel sensory conditions. It may also facilitate the development of customized training regimens that could expedite adaptation to alternate gravitational environments.
Determination of HIV Status in African Adults With Discordant HIV Rapid Tests.
Fogel, Jessica M; Piwowar-Manning, Estelle; Donohue, Kelsey; Cummings, Vanessa; Marzinke, Mark A; Clarke, William; Breaud, Autumn; Fiamma, Agnès; Donnell, Deborah; Kulich, Michal; Mbwambo, Jessie K K; Richter, Linda; Gray, Glenda; Sweat, Michael; Coates, Thomas J; Eshleman, Susan H
2015-08-01
In resource-limited settings, HIV infection is often diagnosed using 2 rapid tests. If the results are discordant, a third tie-breaker test is often used to determine HIV status. This study characterized samples with discordant rapid tests and compared different testing strategies for determining HIV status in these cases. Samples were previously collected from 173 African adults in a population-based survey who had discordant rapid test results. Samples were classified as HIV positive or HIV negative using a rigorous testing algorithm that included two fourth-generation tests, a discriminatory test, and 2 HIV RNA tests. Tie-breaker tests were evaluated, including rapid tests (1 performed in-country), a third-generation enzyme immunoassay, and two fourth-generation tests. Selected samples were further characterized using additional assays. Twenty-nine samples (16.8%) were classified as HIV positive and 24 of those samples (82.8%) had undetectable HIV RNA. Antiretroviral drugs were detected in 1 sample. Sensitivity was 8.3%-43% for the rapid tests; 24.1% for the third-generation enzyme immunoassay; 95.8% and 96.6% for the fourth-generation tests. Specificity was lower for the fourth-generation tests than the other tests. Accuracy ranged from 79.5% to 91.3%. In this population-based survey, most HIV-infected adults with discordant rapid tests were virally suppressed without antiretroviral drugs. Use of individual assays as tie-breaker tests was not a reliable method for determining HIV status in these individuals. More extensive testing algorithms that use a fourth-generation screening test with a discriminatory test and HIV RNA test are preferable for determining HIV status in these cases.
Peterman, Emily M.; Reddy, Steven M.; Saxey, David W.; Snoeyenbos, David R.; Rickard, William D. A.; Fougerouse, Denis; Kylander-Clark, Andrew R. C.
2016-01-01
Isotopic discordance is a common feature in zircon that can lead to an erroneous age determination, and it is attributed to the mobilization and escape of radiogenic Pb during its post-crystallization geological evolution. The degree of isotopic discordance measured at analytical scales of ~10 μm often differs among adjacent analysis locations, indicating heterogeneous distributions of Pb at shorter length scales. We use atom probe microscopy to establish the nature of these sites and the mechanisms by which they form. We show that the nanoscale distribution of Pb in a ~2.1 billion year old discordant zircon that was metamorphosed c. 150 million years ago is defined by two distinct Pb reservoirs. Despite overall Pb loss during peak metamorphic conditions, the atom probe data indicate that a component of radiogenic Pb was trapped in 10-nm dislocation loops that formed during the annealing of radiation damage associated with the metamorphic event. A second Pb component, found outside the dislocation loops, represents homogeneous accumulation of radiogenic Pb in the zircon matrix after metamorphism. The 207Pb/206Pb ratios measured from eight dislocation loops are equivalent within uncertainty and yield an age consistent with the original crystallization age of the zircon, as determined by laser ablation spot analysis. Our results provide a specific mechanism for the trapping and retention of radiogenic Pb during metamorphism and confirm that isotopic discordance in this zircon is characterized by discrete nanoscale reservoirs of Pb that record different isotopic compositions and yield age data consistent with distinct geological events. These data may provide a framework for interpreting discordance in zircon as the heterogeneous distribution of discrete radiogenic Pb populations, each yielding geologically meaningful ages. PMID:27617295
Sleep-EEG in dizygotic twins discordant for Williams syndrome.
Bódizs, Róbert; Gombos, Ferenc; Szocs, Katalin; Réthelyi, János M; Gerván, Patrícia; Kovács, Ilona
2014-01-30
Reports on twin pairs concordant and discordant for Williams syndrome were published before, but no study unravelled sleep physiology in these cases yet. We aim to fill this gap by analyzing sleep records of a twin pair discordant for Williams syndrome extending our focus on presleep wakefulness and sleep spindling. We performed multiplex ligation-dependent probe amplification of the 7q11.23 region of a 17 years old dizygotic opposite-sex twin pair discordant for Williams syndrome. Polysomnography of laboratory sleep at this age was analyzed and followed-up after 1.5 years by ambulatory polysomnography. Sleep stages scoring, EEG power spectra and sleep spindle analyses were carried out. The twin brother showed reduced levels of amplification for all of the probes in the 7q11.23 region indicating a typical deletion spanning at least 1.038 Mb between FKBP6 and CLIP2. The results of the twin sister showed normal copy numbers in the investigated region. Lower sleep times and efficiencies, as well as higher slow wave sleep percents of the twin brother were evident during both recordings. Roughly equal NREM, Stage 2 and REM sleep percents were found. EEG analyses revealed state and derivation-independent decreases in alpha power, lack of an alpha spectral peak in presleep wakefulness, as well as higher NREM sleep sigma peak frequency in the twin brother. Faster sleep spindles with lower amplitude and shorter duration characterized the records of the twin brother. Spectra show a striking reliability and correspondence between the two situations (laboratory vs. home records). Alterations in sleep and specific neural oscillations including the alpha/sigma waves are inherent aspects of Williams syndrome.
Whisman, Mark A; Robustelli, Briana L; Labrecque, Lindsay T
2018-03-25
This longitudinal study was conducted to evaluate actor and partner effects of marital discord on changes in symptoms of depression and generalized anxiety disorder (GAD) in a large population sample of Irish adults (N = 1,445 couples), adjusting for the potential confounds of quality of other social relationships and other psychopathology symptoms. The Actor-Partner Interdependence Model was used to examine actor and partner effects of marital discord on changes in symptoms of depression and GAD at a 2-year follow-up. Additional models examined these associations adjusting for family and friend discord and symptoms of the other type of psychopathology (depressive or GAD symptoms). Actor effects of marital discord on depressive and anxiety symptoms were greater for men than for women. There were significant, positive actor effects of marital discord on depressive symptoms for husbands and wives, which remained significant when adjusting for family and friend discord and GAD symptoms. There were significant, positive actor effects of marital discord on GAD symptoms for husbands, which remained significant when adjusting for family and friend discord and depressive symptoms. Results demonstrate that longitudinal associations between marital discord and depressive symptoms (for wives and husbands) and GAD symptoms (for husbands) are incremental to other rival explanations (family and friend discord and the other set of symptoms). Findings provide evidence for a potential causal association leading from marital discord to symptoms of depression and GAD. © 2018 Family Process Institute.
Heiferman, Michael J; Fawzi, Amani A
2016-12-01
To identify the origin and significance of discordance between blue-light autofluorescence (BL-AF; 488 nm) and near-infrared autofluorescence (NI-AF; 787 nm) in patients with age-related macular degeneration (AMD). A total of 86 eyes of 59 patients with a diagnosis of AMD were included in this cross-sectional study conducted between March 9, 2015 and May 1, 2015. A masked observer examined the BL-AF, NI-AF, and spectral-domain optical coherence tomography images. Areas with discordance of autofluorescence patterns between NI-AF and BL-AF images were correlated with structural findings at the corresponding location in optical coherence tomography scans. Seventy-nine eyes had discordance between BL-AF and NI-AF. The most common optical coherence tomography finding accounting for these discrepancies was pigment migration accounting for 35 lesions in 21 eyes. The most clinically relevant finding was geographic atrophy missed on BL-AF in 7 eyes. Our findings indicate that variations in the distribution of lipofuscin, melanin and melanolipofuscin account for the majority of discordance between BL-AF and NI-AF. Given our finding of missed geographic atrophy lesions on BL-AF in 24% of eyes with geographic atrophy (7/29 eyes), clinicians should consider multimodal imaging, including NI-AF and optical coherence tomography, especially in clinical trials of geographic atrophy.
Heiferman, Michael J.; Fawzi, Amani A.
2016-01-01
Purpose To identify the origin and significance of discordance between blue-light autofluorescence (BL-AF; 488nm) and near-infrared autofluorescence (NI-AF; 787nm) in patients with age-related macular degeneration (AMD). Methods A total of 86 eyes of 59 patients with a diagnosis of AMD were included in this cross-sectional study conducted between March 9, 2015 and May 1, 2015. A masked observer examined the BL-AF, NI-AF, and spectral-domain optical coherence tomography (OCT) images. Areas with discordance of autofluorescence patterns between NI-AF and BL-AF images were correlated with structural findings at the corresponding location in OCT scans. Results 79 eyes had discordance between BL-AF and NI-AF. The most common OCT finding accounting for these discrepancies was pigment migration accounting for 35 lesions in 21 eyes. The most clinically relevant finding was geographic atrophy missed on BL-AF in seven eyes. Conclusions Our findings indicate that variations in the distribution of lipofuscin, melanin and melanolipofuscin account for the majority of discordance between BL-AF and NI-AF. Given our finding of missed geographic atrophy lesions on BL-AF in 24% of eyes with geographic atrophy (7/29 eyes), clinicians should consider multimodal imaging, including NI-AF and OCT, especially in clinical trials of geographic atrophy. PMID:28005672
Epigenetic differences in monozygotic twins discordant for major depressive disorder
Malki, K; Koritskaya, E; Harris, F; Bryson, K; Herbster, M; Tosto, M G
2016-01-01
Although monozygotic (MZ) twins share the majority of their genetic makeup, they can be phenotypically discordant on several traits and diseases. DNA methylation is an epigenetic mechanism that can be influenced by genetic, environmental and stochastic events and may have an important impact on individual variability. In this study we explored epigenetic differences in peripheral blood samples in three MZ twin studies on major depressive disorder (MDD). Epigenetic data for twin pairs were collected as part of a previous study using 8.1-K-CpG microarrays tagging DNA modification in white blood cells from MZ twins discordant for MDD. Data originated from three geographical regions: UK, Australia and the Netherlands. Ninety-seven MZ pairs (194 individuals) discordant for MDD were included. Different methods to address non independently-and-identically distributed (non-i.i.d.) data were evaluated. Machine-learning methods with feature selection centered on support vector machine and random forest were used to build a classifier to predict cases and controls based on epivariations. The most informative variants were mapped to genes and carried forward for network analysis. A mixture approach using principal component analysis (PCA) and Bayes methods allowed to combine the three studies and to leverage the increased predictive power provided by the larger sample. A machine-learning algorithm with feature reduction classified affected from non-affected twins above chance levels in an independent training-testing design. Network analysis revealed gene networks centered on the PPAR−γ (NR1C3) and C-MYC gene hubs interacting through the AP-1 (c-Jun) transcription factor. PPAR−γ (NR1C3) is a drug target for pioglitazone, which has been shown to reduce depression symptoms in patients with MDD. Using a data-driven approach we were able to overcome challenges of non-i.i.d. data when combining epigenetic studies from MZ twins discordant for MDD. Individually, the studies
Epigenetic differences in monozygotic twins discordant for major depressive disorder.
Malki, K; Koritskaya, E; Harris, F; Bryson, K; Herbster, M; Tosto, M G
2016-06-14
Although monozygotic (MZ) twins share the majority of their genetic makeup, they can be phenotypically discordant on several traits and diseases. DNA methylation is an epigenetic mechanism that can be influenced by genetic, environmental and stochastic events and may have an important impact on individual variability. In this study we explored epigenetic differences in peripheral blood samples in three MZ twin studies on major depressive disorder (MDD). Epigenetic data for twin pairs were collected as part of a previous study using 8.1-K-CpG microarrays tagging DNA modification in white blood cells from MZ twins discordant for MDD. Data originated from three geographical regions: UK, Australia and the Netherlands. Ninety-seven MZ pairs (194 individuals) discordant for MDD were included. Different methods to address non independently-and-identically distributed (non-i.i.d.) data were evaluated. Machine-learning methods with feature selection centered on support vector machine and random forest were used to build a classifier to predict cases and controls based on epivariations. The most informative variants were mapped to genes and carried forward for network analysis. A mixture approach using principal component analysis (PCA) and Bayes methods allowed to combine the three studies and to leverage the increased predictive power provided by the larger sample. A machine-learning algorithm with feature reduction classified affected from non-affected twins above chance levels in an independent training-testing design. Network analysis revealed gene networks centered on the PPAR-γ (NR1C3) and C-MYC gene hubs interacting through the AP-1 (c-Jun) transcription factor. PPAR-γ (NR1C3) is a drug target for pioglitazone, which has been shown to reduce depression symptoms in patients with MDD. Using a data-driven approach we were able to overcome challenges of non-i.i.d. data when combining epigenetic studies from MZ twins discordant for MDD. Individually, the studies yielded
Rispel, Laetitia C.; Cloete, Allanise; Metcalf, Carol A.
2015-01-01
Abstract In HIV-discordant relationships, the HIV-negative partner also carries the burden of a stigmatised disease. For this reason, couples often hide their HIV-discordant status from family, friends and community members. This perpetuates the silence around HIV-discordant relationships and impacts on targeted HIV prevention, treatment and counselling efforts. This article reports on experiences of stigma and discrimination among HIV-discordant couples in South Africa, Tanzania and Ukraine. During 2008, HIV-discordant couples who had been in a relationship for at least one year were recruited purposively through health-care providers and civil society organisations in the three countries. Participants completed a brief self-administered questionnaire, while semi-structured interviews were conducted with each partner separately and with both partners together. Interviews were analysed using thematic content analysis. Fifty-one couples were recruited: 26 from South Africa, 10 from Tanzania, and 15 from Ukraine. Although most participants had disclosed their HIV status to someone other than their partner, few were living openly with HIV discordance. Experiences of stigma were common and included being subjected to gossip, rumours and name-calling, and HIV-negative partners being labelled as HIV-positive. Perpetrators of discrimination included family members and health workers. Stigma and discrimination present unique and complex challenges to couples in HIV sero-discordant relationships in these three diverse countries. Addressing stigmatisation of HIV-discordant couples requires a holistic human rights approach and specific programme efforts to address discrimination in the health system. PMID:25778765
Mahoney, A; Jouriles, E N; Scavone, J
1997-12-01
Examined whether marital discord over childrearing contributes to child behavior problems after taking into account general marital adjustment, and if child age moderates associations between child behavior problems and either general marital adjustment or marital discord over childrearing. Participants were 146 two-parent families seeking services for their child's (4 to 9 years of age) conduct problems. Data on marital functioning and child behavior problems were collected from both parents. Mothers' and fathers' reports of marital discord over childrearing related positively to child externalizing problems after accounting for general marital adjustment. Child age moderated associations between fathers' reports of general marital adjustment and both internalizing and externalizing child problems, with associations being stronger in families with younger children. The discussion highlights the role that developmental factors may play in understanding the link between marital and child behavior problems in clinic-referred families.
Mmeje, Okeoma; Chow, Joan M; Davidson, Lisette; Shieh, Jennifer; Schapiro, Jeffrey M; Park, Ina U
2015-10-01
The reverse sequence algorithm is often used for prenatal syphilis screening by high-volume laboratories, beginning with a treponemal test such as the chemiluminescence immunoassay (CIA), followed by testing of CIA-positive (CIA(+)) specimens with the rapid plasma reagin test (RPR). The clinical significance of discordant serology (CIA(+)/RPR(-)) for maternal and neonatal outcomes is unknown. From August 2007 to August 2010, all pregnant women at Kaiser Permanente Northern California with discordant treponemal serology underwent reflexive testing with Treponema pallidum particle agglutination assay (TP-PA) and were categorized as "TP-PA confirmed" (CIA(+)/RPR(-)/TP-PA(+)) or "isolated CIA positive" (CIA(+)/RPR(-)/TP-PA(-)). Demographic variables and clinical data were abstracted from the medical record and compared by TP-PA status. Of 194 pregnant women, 156 (80%) were CIA(+)/RPR(-)/TP-PA(-) and 38 (20%) were CIA(+)/RPR(-)/TP-PA(+). Among the 77 (49%) CIA(+)/RPR(-)/TP-PA(-) women who were retested, 53% became CIA(-). CIA(+)/RPR(-)/TP-PA(+) (n = 38) women were more likely to be older, have a prior history of sexually transmitted infections, and receive treatment for syphilis during pregnancy than women who were CIA(+)/RPR(-)/TP-PA(-) (all P < .005). Most pregnancies (189/194 [97.5%]) resulted in a live birth; there was no difference in birth outcomes according to TP-PA status and no stillbirths attributable to syphilis. Most pregnant women with discordant serology were CIA(+)/RPR(-)/TP-PA(-); more than half who were retested became CIA(-). CIA(+)/RPR(-)/TP-PA(-) serology in pregnancy is likely to be falsely positive. Reflexive testing of discordant specimens with TP-PA is important to stratify risk given the likelihood of false-positive results in this population. © The Author 2015. Published by Oxford University Press on behalf of the Infectious Diseases Society of America. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.
Genome and epigenome analysis of monozygotic twins discordant for congenital heart disease.
Lyu, Guoliang; Zhang, Chao; Ling, Te; Liu, Rui; Zong, Le; Guan, Yiting; Huang, Xiaoke; Sun, Lei; Zhang, Lijun; Li, Cheng; Nie, Yu; Tao, Wei
2018-06-04
Congenital heart disease (CHD) is the leading non-infectious cause of death in infants. Monozygotic (MZ) twins share nearly all of their genetic variants before and after birth. Nevertheless, MZ twins are sometimes discordant for common complex diseases. The goal of this study is to identify genomic and epigenomic differences between a pair of twins discordant for a form of congenital heart disease, double outlet right ventricle (DORV). A monoamniotic monozygotic (MZ) twin pair discordant for DORV were subjected to genome-wide sequencing and methylation analysis. We identified few genomic differences but 1566 differentially methylated regions (DMRs) between the MZ twins. Twenty percent (312/1566) of the DMRs are located within 2 kb upstream of transcription start sites (TSS), containing 121 binding sites of transcription factors. Particularly, ZIC3 and NR2F2 are found to have hypermethylated promoters in both the diseased twin and additional patients suffering from DORV. The results showed a high correlation between hypermethylated promoters at ZIC3 and NR2F2 and down-regulated gene expression levels of these two genes in patients with DORV compared to normal controls, providing new insight into the potential mechanism of this rare form of CHD.
Lahr, Daniel J. G.; Laughinghouse, H. Dail; Oliverio, Angela; Gao, Feng; Katz, Laura A.
2014-01-01
Microscopy has revealed a tremendous diversity of bacterial and eukaryotic forms. More recent molecular analyses show discordance in estimates of biodiversity based on morphological analyses. Moreover, phylogenetic analyses of the diversity of microbial forms have revealed evidence of convergence at scales as large as interdomain – i.e. convergent forms shared between bacteria and eukaryotes. Here, we highlight examples of such discordance, focusing on exemplary lineages such as testate amoebae, ciliates and cyanobacteria, which have long histories of morphological study. We discuss examples in two categories: 1) morphologically identical (or highly similar) individuals that are genetically distinct and 2) morphologically distinct individuals that are genetically distinct. We argue that hypotheses about discordance can be tested using the concept of neutral morphologies, or more broadly neutral phenotypes, as a null hypothesis. PMID:25156897
Kim, Ji Won; Park, Hyoung Keun; Kim, Hyeong Gon; Ham, Dong Yeub; Paick, Sung Hyun; Lho, Yong Soo; Choi, Woo Suk
2015-10-01
We compared location of positive cores in biopsy and location of positive surgical margin (PSM) following radical prostatectomy. This retrospective analysis included patients who were diagnosed as prostate cancer by standard 12-core transrectal ultrasonography guided prostate biopsy, and who have PSM after radical prostatectomy. After exclusion of number of biopsy cores <12, and lack of biopsy location data, 46 patients with PSM were identified. Locations of PSM in pathologic specimen were reported as 6 difference sites (apex, base and lateral in both sides). Discordance of biopsy result and PSM was defined when no positive cores in biopsy was identified at the location of PSM. Most common location of PSM were right apex (n=21) and left apex (n=15). Multiple PSM was reported in 21 specimens (45.7%). In 32 specimens (69.6%) with PSM, one or more concordant positive biopsy cores were identified, but 14 specimens (28%) had no concordant biopsy cores at PSM location. When discordant rate was separated by locations of PSM, right apex PSM had highest rate of discordant (38%). The discordant group had significantly lower prostate volume and lower number of positive cores in biopsy than concordant group. This study showed that one fourth of PSM occurred at location where tumor was not detected at biopsy and that apex PSM had highest rate of discordant. Careful dissection to avoid PSM should be performed in every location, including where tumor was not identified in biopsy.
Coon, Eric R; Maloney, Christopher G; Shen, Mark W
2015-03-01
Imperfect diagnostic tools make it difficult to know the extent to which a bacterial process is contributing to respiratory illness, complicating the decision to prescribe antibiotics. We sought to quantify diagnostic and antibiotic prescribing disagreements between emergency department (ED) and pediatric hospitalist physicians for children admitted with respiratory illness. Manual chart review was used to identify testing, diagnostic, and antibiotic prescribing decisions for consecutive children admitted for respiratory illness in a winter (starting February 20, 2012) and a summer (starting August 20, 2012) season to a tertiary, freestanding children's hospital. Respiratory illness diagnoses were grouped into 3 categories: bacterial, viral, and asthma. A total of 181 children admitted for respiratory illness were studied. Diagnostic discordance was significant for all 3 types of respiratory illness but greatest for bacterial (P<.001). Antibiotic prescribing discordance was significant (P<.001), with pediatric hospitalists changing therapy for 93% of patients prescribed antibiotics in the ED, including stopping antibiotics altogether for 62% of patients. Significant diagnostic and antibiotic discordance between ED and pediatric hospitalist physicians exists for children admitted to the hospital for respiratory illness. Copyright © 2015 by the American Academy of Pediatrics.
Reexamination of strong subadditivity: A quantum-correlation approach
NASA Astrophysics Data System (ADS)
Taghiabadi, Razieh; Akhtarshenas, Seyed Javad; Sarbishaei, Mohsen
2017-03-01
The strong subadditivity inequality of von Neumann entropy relates the entropy of subsystems of a tripartite state ρA B C to that of the composite system. Here, we define T(a )(ρA B C) as the extent to which ρA B C fails to satisfy the strong subadditivity inequality S (ρB) +S (ρC) ≤S (ρA B) +S (ρA C) with equality and investigate its properties. In particular, by introducing auxiliary subsystem E , we consider any purification | ψA B C E> of ρA B C and formulate T(a )(ρA B C) as the extent to which the bipartite quantum correlations of ρA B and ρA C, measured by entanglement of formation and quantum discord, change under the transformation B →B E and C →C E . Invariance of quantum correlations of ρA B and ρA C under such transformation is shown to be a necessary and sufficient condition for vanishing T(a )(ρA B C) . Our approach allows one to characterize, intuitively, the structure of states for which the strong subadditivity is saturated. Moreover, along with providing a conservation law for quantum correlations of states for which the strong subadditivity inequality is satisfied with equality, we find that such states coincide with those that the Koashi-Winter monogamy relation is saturated.
Monozygotic twins discordant for ROHHAD phenotype.
Patwari, Pallavi P; Rand, Casey M; Berry-Kravis, Elizabeth M; Ize-Ludlow, Diego; Weese-Mayer, Debra E
2011-09-01
Rapid-onset obesity with hypothalamic dysfunction, hypoventilation, and autonomic dysregulation (ROHHAD) falls within a group of pediatric disorders with both respiratory control and autonomic nervous system dysregulation. Children with ROHHAD typically present after 1.5 years of age with rapid weight gain as the initial sign. Subsequently, they develop alveolar hypoventilation, autonomic nervous system dysregulation, and, if untreated, cardiorespiratory arrest. To our knowledge, this is the first report of discordant presentation of ROHHAD in monozygotic twins. Twin girls, born at term, had concordant growth and development until 8 years of age. From 8 to 12 years of age, the affected twin developed features characteristic of ROHHAD including obesity, alveolar hypoventilation, scoliosis, hypothalamic dysfunction (central diabetes insipidus, hypothyroidism, premature pubarche, and growth hormone deficiency), right paraspinal/thoracic ganglioneuroblastoma, seizures, and autonomic dysregulation including altered pain perception, large and sluggishly reactive pupils, hypothermia, and profound bradycardia that required a cardiac pacemaker. Results of genetic testing for PHOX2B (congenital central hypoventilation syndrome disease-defining gene) mutations were negative. With early recognition and conservative management, the affected twin had excellent neurocognitive outcome that matched that of the unaffected twin. The unaffected twin demonstrated rapid weight gain later in age but not development of signs/symptoms consistent with ROHHAD. This discordant twin pair demonstrates key features of ROHHAD including the importance of early recognition (especially hypoventilation), complexity of signs/symptoms and clinical course, and importance of initiating comprehensive, multispecialty care. These cases confound the hypothesis of a monogenic etiology for ROHHAD and indicate alternative etiologies including autoimmune or epigenetic phenomenon or a combination of genetic
DOE Office of Scientific and Technical Information (OSTI.GOV)
Altintas, Ferdi, E-mail: ferdialtintas@ibu.edu.tr; Eryigit, Resul, E-mail: resul@ibu.edu.tr
2012-12-15
We have investigated the quantum phase transitions in the ground states of several critical systems, including transverse field Ising and XY models as well as XY with multiple spin interactions, XXZ and the collective system Lipkin-Meshkov-Glick models, by using different quantumness measures, such as entanglement of formation, quantum discord, as well as its classical counterpart, measurement-induced disturbance and the Clauser-Horne-Shimony-Holt-Bell function. Measurement-induced disturbance is found to detect the first and second order phase transitions present in these critical systems, while, surprisingly, it is found to fail to signal the infinite-order phase transition present in the XXZ model. Remarkably, the Clauser-Horne-Shimony-Holt-Bellmore » function is found to detect all the phase transitions, even when quantum and classical correlations are zero for the relevant ground state. - Highlights: Black-Right-Pointing-Pointer The ability of correlation measures to detect quantum phase transitions has been studied. Black-Right-Pointing-Pointer Measurement induced disturbance fails to detect the infinite order phase transition. Black-Right-Pointing-Pointer CHSH-Bell function detects all phase transitions even when the bipartite density matrix is uncorrelated.« less
Environment and initial state engineered dynamics of quantum and classical correlations
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wang, Cheng-Zhi, E-mail: czczwang@outlook.com; Li, Chun-Xian; Guo, Yu
Based on an open exactly solvable system coupled to an environment with nontrivial spectral density, we connect the features of quantum and classical correlations with some features of the environment, initial states of the system, and the presence of initial system–environment correlations. Some interesting features not revealed before are observed by changing the structure of environment, the initial states of system, and the presence of initial system–environment correlations. The main results are as follows. (1) Quantum correlations exhibit temporary freezing and permanent freezing even at high temperature of the environment, for which the necessary and sufficient conditions are given bymore » three propositions. (2) Quantum correlations display a transition from temporary freezing to permanent freezing by changing the structure of environment. (3) Quantum correlations can be enhanced all the time, for which the condition is put forward. (4) The one-to-one dependency relationship between all kinds of dynamic behaviors of quantum correlations and the initial states of the system as well as environment structure is established. (5) In the presence of initial system–environment correlations, quantum correlations under local environment exhibit temporary multi-freezing phenomenon. While under global environment they oscillate, revive, and damp, an explanation for which is given. - Highlights: • Various interesting behaviors of quantum and classical correlations are observed in an open exactly solvable model. • The important effects of the bath structure on quantum and classical correlations are revealed. • The one-to-one correspondence between the type of dynamical behavior of quantum discord and the initial state is given. • Quantum correlations are given in the presence of initial qubits–bath correlations.« less
Kao, Yung Hsiang; Tan, Eik Hock; Teo, Terence Kiat Beng; Ng, Chee Eng; Goh, Soon Whatt
2011-11-01
During pre-therapy evaluation for yttrium-90 (Y-90) radioembolization, it is uncommon to find severe imaging discordance between hepatic angiography versus technetium-99m-macroaggregated albumin (Tc-99m-MAA) single photon emission computed tomography with integrated low-dose CT (SPECT/CT). The reasons for severe imaging discordance are unclear, and literature is scarce. We describe 3 patients with severe imaging discordance, whereby tumor angiographic contrast hypervascularity was markedly mismatched to the corresponding Tc-99m-MAA SPECT/CT, and its clinical impact. The incidence of severe imaging discordance at our institution was 4% (3 of 74 cases). We postulate that imaging discordance could be due to a combination of 3 factors: (1) different injection rates between soluble contrast molecules versus Tc-99m-MAA; (2) different arterial flow hemodynamics between soluble contrast molecules versus Tc-99m-MAA; (3) eccentric release position of Tc-99m-MAA due to microcatheter tip location, inadvertently selecting non-target microparticle trajectories. Tc-99m-MAA SPECT/CT more accurately represents hepatic microparticle biodistribution than soluble contrast hepatic angiography and should be a key criterion in patient selection for Y-90 radioembolization. Tc-99m-MAA SPECT/CT provides more information than planar scintigraphy to guide radiation planning and clinical decision making. Severe imaging discordance at pre-therapy evaluation is ominous and should be followed up by changes to the final vascular approach during Y-90 radioembolization.
Floré, Vincent; Claus, Piet; Symons, Rolf; Smith, Godfrey L; Sipido, Karin R; Willems, Rik
2013-08-01
There is convincing experimental evidence that cellular action potential duration (APD) alternans is arrhythmogenic but its relationship with body surface microvolt T-wave alternans (MTWA) remains unclear. We investigated the relationship between MTWA and APD alternans induced by alternating cycle length (CL) pacing in a pig model. In 10 pigs, catheters in the right atrium (RA) and right (RV) and left ventricle (LV) allowed pacing and recording of monophasic action potentials (MAP). During RA pacing at stable 500-ms CL, LV was paced at alternating CL (505 ms and 495 ms). Changing the alternating LV (A-LV) pacing delay changes the size of the region with alternating ventricular activation. Spectral analysis of intracardiac MAP was correlated with body surface MTWA. In a similar setup (during alternating pacing in RV and LV), we investigated concordant versus discordant APD alternans. Pacing the LV with subtle alternating cycle lengths at short A-LV delay leads to broad QRS (97 ± 10 ms), body surface MTWA (mean Valt 4.2 ± 1.8 µV), and positive RR-interval alternans. At longer A-LV delay, not resulting in QRS widening (68 ± 5 ms), body surface RR alternans was absent but MTWA remained detectable and was even more pronounced (8.7 ± 5.1 µV, P < 0.01). During both concordant and discordant pacing MTWA was present. The precordial leads were better for detecting discordant APD alternans (8.0 ± 2.9 µV and 12.8 ± 4.52 µV, P = 0.02). MTWA is a potent technique to detect subtle and isolated intracardiac APD alternans that is artificially induced by alternating pacing. In the same model, discordant activation alternans can only be discriminated from concordant when using a quantifying approach of MTWA analysis. ©2013, The Authors. Journal compilation ©2013 Wiley Periodicals, Inc.
Predictors of Discordance between Symptoms and Signs in Dry Eye Disease.
Vehof, Jelle; Sillevis Smitt-Kamminga, Nicole; Nibourg, Simone A; Hammond, Christopher J
2017-03-01
To investigate predictors of discordance between symptoms and signs in dry eye disease (DED). Cross-sectional association study. A total of 648 patients with dry eye from the Groningen LOngitudinal Sicca StudY (GLOSSY), a tertiary dry eye clinic patient cohort from the Netherlands. Patient symptoms were assessed using the Ocular Surface Disease Index (OSDI) questionnaire. Dry eye signs were assessed by tear osmolarity, Schirmer test, tear breakup time, corneal and conjunctival staining, and meibomian gland dysfunction, all in both eyes, and a composite dry eye signs severity score was calculated from these 6 tests for each patient. Linear regression analysis was used to test the association of discordance between symptoms and signs with a wide range of independent variables (demographic and environmental variables, systemic diseases, ocular traits, and medications). Predictors of discordance between symptoms and signs in DED, defined by the difference between the rank score of the OSDI and the rank score of the dry eye signs severity score. Of the 648 subjects in this cohort, 536 (82.7%) were female and the mean age was 55.8 years (standard deviation, 15.6 years). Significant predictors of greater symptoms than signs were the presence of a chronic pain syndrome, atopic diseases, a known allergy, the use of antihistamines (all P < 0.001), depression (P = 0.003), osteoarthritis (P = 0.008), and the use of antidepressants (P = 0.02). Predictors of lesser symptoms than signs were increased age (P < 0.001) and the presence of Sjögren's disease (P < 0.001) (primary Sjögren's disease, P < 0.001) more than secondary Sjögren's disease (P = 0.08), and graft-versus-host disease (P = 0.04). Furthermore, greater symptoms compared with signs were highly associated with lower self-perceived health (P < 0.001). This large clinical study has shown that discordance between symptoms and signs in DED is an indicator of self-perceived health. The study found important
Han, Yoonsun; Grogan-Kaylor, Andrew; Bares, Cristina; Ma, Julie; Castillo, Marcela; Delva, Jorge
2012-01-01
This study investigated the role of discrepancies between parent and youth reports of perceived parental monitoring in adolescent problem behaviors with a Chilean sample (N= 850). Higher levels of discordance concerning parental monitoring predicted greater levels of maladaptive youth behaviors. A positive association between parent-youth discordance and externalizing problems indicated that large adult-youth disagreement in parental monitoring may impose a great risk, despite protective efforts of parental monitoring. Although the direct relationship between parental monitoring and youth internalizing behaviors was not significant, parent-youth incongruence in monitoring was associated with greater levels of internalizing behaviors. Therefore, differing assessments of parental behaviors, as an indicator of less optimal family functioning, may provide important information about youth maladjustment and may potentially provide a beginning point for family-focused intervention. PMID:23097593
Psychiatric outcomes of bullying victimization: a study of discordant monozygotic twins.
Silberg, J L; Copeland, W; Linker, J; Moore, A A; Roberson-Nay, R; York, T P
2016-07-01
Bullying victimization in childhood is associated with a broad array of serious mental health disturbances, including anxiety, depression, and suicidal ideation and behavior. The key goal of this study was to evaluate whether bullying victimization is a true environmental risk factor for psychiatric disturbance using data from 145 bully-discordant monozygotic (MZ) juvenile twin pairs from the Virginia Twin Study of Adolescent Behavioral Development (VTSABD) and their follow-up into young adulthood. Since MZ twins share an identical genotype and familial environment, a higher rate of psychiatric disturbance in a bullied MZ twin compared to their non-bullied MZ co-twin would be evidence of an environmental impact of bullying victimization. Environmental correlations between being bullied and the different psychiatric traits were estimated by fitting structural equation models to the full sample of MZ and DZ twins (N = 2824). Environmental associations were further explored using the longitudinal data on the bullying-discordant MZ twins. Being bullied was associated with a wide range of psychiatric disorders in both children and young adults. The analysis of data on the MZ-discordant twins supports a genuine environmental impact of bullying victimization on childhood social anxiety [odds ratio (OR) 1.7], separation anxiety (OR 1.9), and young adult suicidal ideation (OR 1.3). There was a shared genetic influence on social anxiety and bullying victimization, consistent with social anxiety being both an antecedent and consequence of being bullied. Bullying victimization in childhood is a significant environmental trauma and should be included in any mental health assessment of children and young adults.
Rispel, Laetitia C; Metcalf, Carol A; Moody, Kevin; Cloete, Allanise; Caswell, Georgina
2011-05-01
This article reports on the influence of HIV on sexual relations and childbearing decisions of 36 HIV-discordant couples, 26 in South Africa and 10 in Tanzania, recruited into an exploratory study through hospital antiretroviral treatment clinics and civil society organisations working with people living with HIV. Self-administered questionnaires were used to obtain social and demographic information, while couples' sexual relations and childbearing decisions were explored through in-depth, semi-structured individual and couple interviews. The majority of the HIV-positive partners were women, who were on antiretroviral treatment. Almost one-third of South African respondents and half of those in Tanzania reported experiences of tension related to HIV-discordance, while more than half of the South Africans and almost three-quarters of the Tanzanians reported that intimacy had been affected by their discordant status. Those without children were more likely to desire children (17/23) than those who already had children (16/44), although this desire was influenced by fear of HIV transmission to the negative partner and medical professional advice. The study points to the need for targeted information for HIV discordant couples, as well as couple counselling and support services. Copyright © 2011 Reproductive Health Matters. Published by Elsevier Ltd. All rights reserved.
Caussy, Cyrielle; Chen, Jun; Alquiraish, Mosab H; Cepin, Sandra; Nguyen, Phirum; Hernandez, Carolyn; Yin, Meng; Bettencourt, Ricki; Cachay, Edward R; Jayakumar, Saumya; Fortney, Lynda; Hooker, Jonathan; Sy, Ethan; Valasek, Mark A; Rizo, Emily; Richards, Lisa; Brenner, David A; Sirlin, Claude B; Ehman, Richard L; Loomba, Rohit
2018-01-17
Magnetic resonance elastography (MRE) and transient elastography (TE) are noninvasive techniques used to detect liver fibrosis in nonalcoholic fatty liver disease. MRE detects fibrosis more accurately than TE, but MRE is more expensive, and the concordance between MRE and TE have not been optimally assessed in obese patients. It is important to determine under which conditions TE and MRE produce the same readings, so that some patients can simply undergo TE evaluation to detect fibrosis. We aimed to assess the association between body mass index (BMI) and discordancy between MRE and TE findings, using liver biopsy as the reference, and validated our findings in a separate cohort. We performed a cross-sectional study of 119 adults with nonalcoholic fatty liver disease who underwent MRE, TE with M and XL probe, and liver biopsy analysis from October 2011 through January 2017 (training cohort). MRE and TE results were considered to be concordant if they found patients to have the same stage fibrosis as liver biopsy analysis. We validated our findings in 75 adults with nonalcoholic fatty liver disease who underwent contemporaneous MRE, TE, and liver biopsy at a separate institution from March 2010 through May 2013. The primary outcome was rate of discordance between MRE and TE in determining stage of fibrosis (stage 2-4 vs 0-1). Secondary outcomes were the rate of discordance between MRE and TE in determining dichotomized stage of fibrosis (1-4 vs 0, 3-4 vs 0-2, and 4 vs 0-3). In the training cohort, there was 43.7% discordance in findings from MRE versus TE. BMI associated significantly with discordance in findings from MRE versus TE (odds ratio, 1.69; 95% confidence interval, 1.15-2.51; P = .008) after multivariable adjustment by age and sex. The findings were confirmed in the validation cohort: there was 45.3% discordance in findings from MRE versus TE. BMI again associated significantly with discordance in findings from MRE versus TE (odds ratio, 1.52; 95
Hripcsak, George; Knirsch, Charles; Zhou, Li; Wilcox, Adam; Melton, Genevieve B
2007-03-01
Data mining in electronic medical records may facilitate clinical research, but much of the structured data may be miscoded, incomplete, or non-specific. The exploitation of narrative data using natural language processing may help, although nesting, varying granularity, and repetition remain challenges. In a study of community-acquired pneumonia using electronic records, these issues led to poor classification. Limiting queries to accurate, complete records led to vastly reduced, possibly biased samples. We exploited knowledge latent in the electronic records to improve classification. A similarity metric was used to cluster cases. We defined discordance as the degree to which cases within a cluster give different answers for some query that addresses a classification task of interest. Cases with higher discordance are more likely to be incorrectly classified, and can be reviewed manually to adjust the classification, improve the query, or estimate the likely accuracy of the query. In a study of pneumonia--in which the ICD9-CM coding was found to be very poor--the discordance measure was statistically significantly correlated with classification correctness (.45; 95% CI .15-.62).
Hayden, Elizabeth P.; Klein, Daniel N.; Dougherty, Lea R.; Olino, Thomas M.; Dyson, Margaret W.; Durbin, C. Emily; Sheikh, Haroon I.; Singh, Shiva M.
2012-01-01
The brain-derived neurotrophic factor (BDNF) gene is a plausible candidate for early-emerging negative emotionality (NE), and evidence suggests that the effects of this gene may be especially salient in the context of familial risk for child maladjustment. We therefore examined whether the BDNF val66met polymorphism was associated with child NE in the context of parental depression and relationship discord. A sample of 413 three-year-old children was assessed for NE using standardized laboratory measures. Parents completed clinical interviews and a measure of marital satisfaction. Children with at least one BDNF met allele exhibited elevated NE when a parent had a history of depressive disorder, or when relationship discord was present. In contrast, this allele was associated with especially low NE when parent depression was absent, and when the parental relationship was not discordant. Findings suggest that the BDNF met allele confers increased child sensitivity to both positive and negative familial influences. PMID:20921572
Peasley-Miklus, Catherine E; Panayiotou, Georgia; Vrana, Scott R
2016-03-01
Alexithymia is believed to involve deficits in emotion processing and imagery ability. Previous findings suggest that it is especially related to deficits in processing the arousal dimension of emotion, and that discordance may exist between self-report and physiological responses to emotional stimuli in alexithymia. The current study used a well-established emotional imagery paradigm to examine emotion processing deficits and discordance in participants (N = 86) selected based on their extreme scores on the Toronto Alexithymia Scale-20. Physiological (skin conductance, heart rate, and corrugator and zygomaticus electromyographic responses) and self-report (valence, arousal ratings) responses were monitored during imagery of anger, fear, joy, and neutral scenes and emotionally neutral high arousal (action) scenes. Results from regression analyses indicated that alexithymia was largely unrelated to responses on valence-based measures (facial electromyography, valence ratings), but that it was related to arousal-based measures. Specifically, alexithymia was related to higher heart rate during neutral and lower heart rate during fear imagery. Alexithymia did not predict differential responses to action versus neutral imagery, suggesting specificity of deficits to emotional contexts. Evidence for discordance between physiological responses and self-report in alexithymia was obtained from within-person analyses using multilevel modeling. Results are consistent with the idea that alexithymic deficits are specific to processing emotional arousal, and suggest difficulties with parasympathetic control and emotion regulation. Alexithymia is also associated with discordance between self-reported emotional experience and physiological response to emotion, consistent with prior evidence. (c) 2016 APA, all rights reserved).
Detecting discordance enrichment among a series of two-sample genome-wide expression data sets.
Lai, Yinglei; Zhang, Fanni; Nayak, Tapan K; Modarres, Reza; Lee, Norman H; McCaffrey, Timothy A
2017-01-25
With the current microarray and RNA-seq technologies, two-sample genome-wide expression data have been widely collected in biological and medical studies. The related differential expression analysis and gene set enrichment analysis have been frequently conducted. Integrative analysis can be conducted when multiple data sets are available. In practice, discordant molecular behaviors among a series of data sets can be of biological and clinical interest. In this study, a statistical method is proposed for detecting discordance gene set enrichment. Our method is based on a two-level multivariate normal mixture model. It is statistically efficient with linearly increased parameter space when the number of data sets is increased. The model-based probability of discordance enrichment can be calculated for gene set detection. We apply our method to a microarray expression data set collected from forty-five matched tumor/non-tumor pairs of tissues for studying pancreatic cancer. We divided the data set into a series of non-overlapping subsets according to the tumor/non-tumor paired expression ratio of gene PNLIP (pancreatic lipase, recently shown it association with pancreatic cancer). The log-ratio ranges from a negative value (e.g. more expressed in non-tumor tissue) to a positive value (e.g. more expressed in tumor tissue). Our purpose is to understand whether any gene sets are enriched in discordant behaviors among these subsets (when the log-ratio is increased from negative to positive). We focus on KEGG pathways. The detected pathways will be useful for our further understanding of the role of gene PNLIP in pancreatic cancer research. Among the top list of detected pathways, the neuroactive ligand receptor interaction and olfactory transduction pathways are the most significant two. Then, we consider gene TP53 that is well-known for its role as tumor suppressor in cancer research. The log-ratio also ranges from a negative value (e.g. more expressed in non
ERIC Educational Resources Information Center
Asbury, Kathryn; Dunn, Judy; Plomin, Robert
2006-01-01
Non-shared environmental influence (NSE) has been found to account for around 50 percent of anxiety variance, but specific NSE factors have not been identified. Discordant monozygotic (MZ) twins can be used to generate relevant hypotheses because MZ discordance can be caused by NSE, but not by genes or shared environment. Of 1590 MZ pairs teacher…
Psychiatric outcomes of bullying victimization: A study of discordant monozygotic twins
Silberg, Judy L.; Copeland, William; Linker, Julie; Moore, Ashlee A.; Roberson-Nay, Roxann; York, Timothy P.
2016-01-01
Background Bullying victimization in childhood is associated with a broad array of serious mental health disturbances, including anxiety, depression, and suicidal ideation and behavior. The key goal of this study was to evaluate whether bullying victimization is a true environmental risk factor for psychiatric disturbance using data from 145 bully-discordant monozygotic (MZ) juvenile twin pairs from the Virginia Twin Study of Adolescent Behavioral Development (VTSABD) and their follow-up into young adulthood. Method Since MZ twins share an identical genotype and familial environment, a higher rate of psychiatric disturbance in a bullied MZ twin compared to their non-bullied MZ co-twin would be evidence of an environmental impact of bullying victimization. Environmental correlations between being bullied and the different psychiatric traits were estimated by fitting structural equation models to the full sample of MZ and DZ twins (N = 2824). Environmental associations were further explored using the longitudinal data on the bullying-discordant MZ twins. Results Being bullied was associated with a wide range of psychiatric disorders in both children and young adults. The analysis of data on the MZ-discordant twins supports a genuine environmental impact of bullying victimization on childhood social anxiety [odds ratio (OR) 1.7], separation anxiety (OR 1.9), and young adult suicidal ideation (OR 1.3). There was a shared genetic influence on social anxiety and bullying victimization, consistent with social anxiety being both an antecedent and consequence of being bullied. Conclusion Bullying victimization in childhood is a significant environmental trauma and should be included in any mental health assessment of children and young adults. PMID:26979565
Leong, K P; Chong, E Y Y; Kong, K O; Chan, S P; Thong, B Y H; Lian, T Y; Chng, H H; Koh, E T; Teh, C L; Lau, T C; Law, W G; Cheng, Y K; Badsha, H; Chew, L C; Yong, W H; Howe, H S
2010-01-01
Patients with systemic lupus erythematosus often assess their disease activity differently from their physicians. We studied the factors associated with this discordance. The data provided by 534 systemic lupus erythematosus patients were analyzed. We compared the physician and patient assessments of lupus activity on a visual-assessment scale from the same visit. We collected clinical data and scores from MOS 36-Item Short-Form Health Survey, Systemic Lupus Erythematosus Quality-of-Life Questionnaire, Rheumatology Attitudes Index, Systemic Lupus Erythematosus Disease Activity Index, and revised Systemic Lupus Activity Measure. Patients tended to score their disease activity higher than do their physicians, when these factors were present: poorer general health assessment, presence of thrombocytopenia, hypertension and urinary sediments, and difficulty in carrying groceries. Physicians tended to score the disease activity higher than do the patients in these circumstances proteinuria, hemolysis, use of azathioprine or cyclophosphamide, tiredness, photosensitivity, higher revised Systemic Lupus Activity Measure score, casturia, and patient report of being more easily ill than are other patients. There was only moderate correlation between the discordance in the baseline and the subsequent visits. The physician assessment of disease activity at baseline correlated better with an objective measure of disease activity (revised Systemic Lupus Activity Measure) in the subsequent visit than the patient assessment. In conclusion, discordance in the perception of disease activity between patients and physicians may be amenable to intervention.
Benford's law gives better scaling exponents in phase transitions of quantum XY models.
Rane, Ameya Deepak; Mishra, Utkarsh; Biswas, Anindya; Sen De, Aditi; Sen, Ujjwal
2014-08-01
Benford's law is an empirical law predicting the distribution of the first significant digits of numbers obtained from natural phenomena and mathematical tables. It has been found to be applicable for numbers coming from a plethora of sources, varying from seismographic, biological, financial, to astronomical. We apply this law to analyze the data obtained from physical many-body systems described by the one-dimensional anisotropic quantum XY models in a transverse magnetic field. We detect the zero-temperature quantum phase transition and find that our method gives better finite-size scaling exponents for the critical point than many other known scaling exponents using measurable quantities like magnetization, entanglement, and quantum discord. We extend our analysis to the same system but at finite temperature and find that it also detects the finite-temperature phase transition in the model. Moreover, we compare the Benford distribution analysis with the same obtained from the uniform and Poisson distributions. The analysis is furthermore important in that the high-precision detection of the cooperative physical phenomena is possible even from low-precision experimental data.
Rosenberg, Nora E; Pettifor, Audrey E; Bruyn, Guy DE; Westreich, Daniel; Delany-Moretlwe, Sinead; Behets, Frieda; Maman, Suzanne; Coetzee, David; Kamupira, Mercy; Miller, William C
2012-01-01
Introduction Effective behavioral HIV prevention is needed for stable HIV-discordant couples at risk for HIV, especially those without access to biomedical prevention. This analysis addressed whether HIV testing and counseling (HTC) with ongoing counseling and condom distribution lead to reduced unprotected sex in HIV-discordant couples. Methods Partners in Prevention HSV/HIV Transmission Study was a randomized trial conducted from 2004–2008 assessing whether acyclovir reduced HIV transmission from HSV-2/HIV-1 co-infected persons to HIV-uninfected sex partners. This analysis relied on self-reported behavioral data from 508 HIV-infected South African participants. The exposure was timing of first HTC: 0–7, 8–14, 15–30, or >30 days before baseline. In each exposure group, predicted probabilities of unprotected sex in the last month were calculated at baseline, month one, and month twelve using generalized estimating equations with a logit link and exchangeable correlation matrix. Results At baseline, participants who knew their HIV status for less time experienced higher predicted probabilities of unprotected sex in the last month: 0–7 days, 0.71; 8–14 days, 0.52; 15–30 days, 0.49; >30 days, 0.26. At month one, once all participants had been aware of being in HIV-discordant relationships for ≥ 1 month, predicted probabilities declined: 0–7 days, 0.08; 8–14 days, 0.08; 15–30 days, 0.15; >30 days, 0.14. Lower predicted probabilities were sustained through month twelve: 0–7 days, 0.08; 8–14 days, 0.11; 15–30 days, 0.05; >30 days, 0.19. Conclusions Unprotected sex declined after HIV-positive diagnosis, and declined further after awareness of HIV-discordance. Identifying HIV-discordant couples for behavioral prevention is important for reducing HIV transmission risk. PMID:23117500
A simulator for discrete quantum walks on lattices
NASA Astrophysics Data System (ADS)
Rodrigues, J.; Paunković, N.; Mateus, P.
In this paper, we present a simulator for two-particle quantum walks on the line and one-particle on a two-dimensional squared lattice. It can be used to investigate the equivalence between the two cases (one- and two-particle walks) for various boundary conditions (open, circular, reflecting, absorbing and their combinations). For the case of a single walker on a two-dimensional lattice, the simulator can also implement the Möbius strip. Furthermore, other topologies for the walker are also simulated by the proposed tool, like certain types of planar graphs with degree up to 4, by considering missing links over the lattice. The main purpose of the simulator is to study the genuinely quantum effects on the global properties of the two-particle joint probability distribution on the entanglement between the walkers/axis. For that purpose, the simulator is designed to compute various quantities such as: the entanglement and classical correlations, (classical and quantum) mutual information, the average distance between the two walkers, different hitting times and quantum discord. These quantities are of vital importance in designing possible algorithmic applications of quantum walks, namely in search, 3-SAT problems, etc. The simulator can also implement the static partial measurements of particle(s) positions and dynamic breaking of the links between certain nodes, both of which can be used to investigate the effects of decoherence on the walker(s). Finally, the simulator can be used to investigate the dynamic Anderson-like particle localization by varying the coin operators of certain nodes on the line/lattice. We also present some illustrative and relevant examples of one- and two-particle quantum walks in various scenarios. The tool was implemented in C and is available on-line at http://qwsim.weebly.com/.
Seddon, Johanna M.; Reynolds, Robyn; Shah, Heeral R.; Rosner, Bernard
2012-01-01
Objective We evaluated monozygotic twin pairs with discordant age-related macular degeneration (AMD) phenotypes to assess differences in behavioral and nutritional factors. Design Case series. Participants Caucasian male twin pairs from the United States Twin Study of Macular Degeneration. Methods Twin pairs were genotyped to confirm monozygosity. Ocular characteristics were evaluated based on fundus photographs using the Wisconsin Grading System and a 5-grade Clinical Age-Related Maculopathy Staging System. We selected twin pairs discordant in each of the following phenotypic categories: Stage of AMD (n = 28), drusen area (n = 60), drusen size (n = 40), and increased pigment area (n = 56). The Wilcoxon signed-rank test and linear regression were used to assess associations between behavioral and nutritional characteristics and each phenotype within discordant twin pairs. Main Outcome Measures Differences in smoking and dietary factors within twin pairs discordant for stage of AMD, drusen area, drusen size, and pigment area. Results Representative fundus photographs depict the discordant phenotypes. Pack-years of smoking were higher for the twin with the more advanced stage of AMD (P = 0.05). Higher dietary intake of vitamin D was present in the twins with less severe AMD (P = 0.01) and smaller drusen size (P = 0.05) compared with co-twins, adjusted for smoking and age. Dietary intakes of betaine and methionine were significantly higher in the twin with lower stage of AMD (P = 0.009) and smaller drusen area (P = 0.03), respectively. Conclusions The twin with the more advanced stage of AMD, larger drusen area, drusen size, and pigment area tended to be the heavier smoker. The twin with the earlier stage of AMD, smaller drusen size and area, and less pigment tended to have higher dietary vitamin D, betaine, or methionine intake. Results suggest that behavioral and nutritional factors associated with epigenetic mechanisms are involved in the etiology of AMD, in
Shuaib, Faisal M B; Ehiri, John E; Jolly, Pauline; Zhang, Qionghui; Emusu, Donath; Ngu, Julius; Foushee, Herman; Katongole, Drake; Kirby, Russell; Wabwire-Mangen, Fred
2012-01-01
HIV serodiscordance is a sexual partnership in which one partner is infected with HIV while the other is not. Managing emotional and sexual intimacy in HIV serodiscordant unions can be difficult due to concerns about HIV transmission and the challenge of initiating and maintaining safe sex. In situations where couples are jointly aware of their HIV status, women in serodiscordant unions may face increased risk of partner violence. We conducted an investigation to assess risk factors for HIV serodiscordance and determine if HIV serodiscordance is associated with incident sexual violence among a cohort of women attending HIV post-test club services at three AIDS Information Centers (AICs) in Uganda. Using a prospective study of 250 women, we elicited information about sexual violence using structured face-to-face interviews. Sexual violence and risk factors were assessed and compared among HIV positive women in HIV discordant unions, HIV negative women in discordant unions, and HIV negative women in negative concordant unions. Multivariable logistic regression was used to assess the association between participants' serostatus and sexual violence. HIV negative women in serodiscordant relationships (36.1±11.1 years, range: 19-65 years) were significantly older than either HIV positive women in serodiscordant relationships (32.2±9.0 years, range: 18-56 years), or HIV negative women in concordant relationships (32.3±11.0 years, range: 18-62), (p=0.033). Early age at sexual debut was associated with a 2.4-fold increased risk of experiencing sexual violence (OR 2.4, 95% CI 1.27-4.65). Based on unadjusted analysis, HIV positive women in discordant relationship were at highest risk for sexual violence compared to HIV negative women in discordant unions, and HIV negative women in negative concordant unions. HIV negative women in discordant relationships and those in concordant negative relationships showed no increased risk for sexual violence. However, couples' HIV
Mito-nuclear discord in six congeneric lineages of Holarctic ducks (genus Anas).
Peters, Jeffrey L; Winker, Kevin; Millam, Kendra C; Lavretsky, Philip; Kulikova, Irina; Wilson, Robert E; Zhuravlev, Yuri N; McCracken, Kevin G
2014-06-01
Many species have Holarctic distributions that extend across Europe, Asia and North America. Most genetics research on these species has examined only mitochondrial (mt) DNA, which has revealed wide variance in divergence between Old World (OW) and New World (NW) populations, ranging from shallow, unstructured genealogies to deeply divergent lineages. In this study, we sequenced 20 nuclear introns to test for concordant patterns of OW-NW differentiation between mtDNA and nuclear (nu) DNA for six lineages of Holarctic ducks (genus Anas). Genetic differentiation for both marker types varied widely among these lineages (idiosyncratic population histories), but mtDNA and nuDNA divergence within lineages was not significantly correlated. Moreover, compared with the association between mtDNA and nuDNA divergence observed among different species, OW-NW nuDNA differentiation was generally lower than mtDNA divergence, at least for lineages with deeply divergent mtDNA. Furthermore, coalescent estimates indicated significantly higher rates of gene flow for nuDNA than mtDNA for four of the six lineages. Thus, Holarctic ducks show prominent mito-nuclear discord between OW and NW populations, and we reject differences in sorting rates as the sole cause of the within-species discord. Male-mediated intercontinental gene flow is likely a leading contributor to this discord, although selection could also cause increased mtDNA divergence relative to weak nuDNA differentiation. The population genetics of these ducks contribute to growing evidence that mtDNA can be an unreliable indicator of stage of speciation and that more holistic approaches are needed for species delimitation. © 2014 John Wiley & Sons Ltd.
Metabolome and fecal microbiota in monozygotic twin pairs discordant for weight: a Big Mac challenge
Bondia-Pons, Isabel; Maukonen, Johanna; Mattila, Ismo; Rissanen, Aila; Saarela, Maria; Kaprio, Jaakko; Hakkarainen, Antti; Lundbom, Jesper; Lundbom, Nina; Hyötyläinen, Tuulia; Pietiläinen, Kirsi H.; Orešič, Matej
2014-01-01
Postprandial responses to food are complex, involving both genetic and environmental factors. We studied postprandial responses to a Big Mac meal challenge in monozygotic co-twins highly discordant for body weight. This unique design allows assessment of the contribution of obesity, independent of genetic liability. Comprehensive metabolic profiling using 3 analytical platforms was applied to fasting and postprandial serum samples from 16 healthy monozygotic twin pairs discordant for weight (body mass index difference >3 kg/m2). Nine concordant monozygotic pairs were examined as control pairs. Fecal samples were analyzed to assess diversity of the major bacterial groups by using 5 different validated bacterial group specific denaturing gradient gel electrophoresis methods. No differences in fecal bacterial diversity were detected when comparing co-twins discordant for weight (ANOVA, P<0.05). We found that within-pair similarity is a dominant factor in the metabolic postprandial response, independent of acquired obesity. Branched chain amino acids were increased in heavier as compared with leaner co-twins in the fasting state, but their levels converged postprandially (paired t tests, FDR q<0.05). We also found that specific bacterial groups were associated with postprandial changes of specific metabolites. Our findings underline important roles of genetic and early life factors in the regulation of postprandial metabolite levels.—Bondia-Pons, I., Maukonen, J., Mattila, I., Rissanen, A., Saarela, M., Kaprio, J., Hakkarainen, A., Lundbom, J., Lundbom, N., Hyötyläinen, T., Pietiläinen, K. H., Orešič, M. Metabolome and fecal microbiota in monozygotic twin pairs discordant for weight: a Big Mac challenge. PMID:24846387
Monozygotic twin discordant for Down syndrome: mos 47,XX,+21/46,XX and 46,XX.
Choi, Sun Ah; Ko, Jung Min; Shin, Choong Ho; Yang, Sei Won; Choi, Jin Sun; Oh, Sun Kyung
2013-08-01
Monozygotic twins, developed from a single zygote, are almost identical in clinical phenotype and concordant karyotypes. Monozygotic twins with discordant karyotypes are thought to be quite rare. Here, we report monochorionic-diamniotic twins discordant for Down syndrome. On findings of prenatal ultrasonography, nuchal translucency thickness was different between twins, and suggested that one of the twins was at high risk for having chromosomal abnormalities including Down syndrome. The twins were monochorionic-diamniotic; therefore, chorionic villi sampling of the common placenta was performed. The karyotype of the chorionic villi cells was 46,XX, and pregnancy was maintained. After delivery, dysmorphic clinical features suggesting Down syndrome were found in one of the twins, while the other twin showed a morphologically normal appearance. Karyotypes of peripheral blood leukocytes were repeatedly normal in the dysmorphic twin; however, the karyotype of skin fibroblasts from the dysmorphic twin indicated Down syndrome mosaicism; 47,XX,+21[99]/46,XX[2]. The karyotype of skin fibroblasts from the morphologically normal twin was 46,XX. Monozygosity of the twins was confirmed by a short tandem repeat analysis using 16 polymorphic markers. A mitotic nondisjunction followed by the twinning would explain the discordant karyotypes between monozygotic twins.
Movement Discordance between Healthy and Non-Healthy US Adults
Swartz, Ann M.; Cho, Young; Welch, Whitney A.; Strath, Scott J.
2016-01-01
Introduction Physical activity is known to significantly impact cardiometabolic health. Accelerometer data, as a measure of physical activity, can be used to objectively identify a disparity in movement (movement discordance) between healthy and unhealthy adults. The purpose of this study was to examine the Movement Discordance between healthy and unhealthy adults in a large US population sample. Methods Demographic, health and accelerometer data from the National Health and Nutrition Examination Study (NHANES) 2003–2004 and 2005–2006 cohorts were used for this study. Participants were classified as either having a “normal” or “abnormal” value for each cardiometabolic health parameter examined, based on published criteria. Linear regression analyses were performed to determine significance of each abnormal health parameter (risk factor) in its unique effect on the accelerometer counts, controlling for age and gender. Average accelerometer counts per minute (cpm) by gender and age categories were estimated separately for the groups of normal and abnormal cardiometabolic risk. Results Average cpm for those with healthy levels of each individual cardiometabolic health parameter range from 296 cpm (for C reactive protein) to 337 cpm (for waist circumference), while average cpm for those with abnormal levels of each individual cardiometabolic health parameter range from 216 cpm (for insulin) to 291 cpm (for LDL-cholesterol). After controlling for age and gender, waist circumference, HbA1c, Insulin, Homocysteine, and HDL-Cholesterol were the cardiometabolic health parameters that showed significant, unique and independent effects on cpm. Overall, individuals who have abnormal values for all significant cardiometabolic health parameters (“unhealthy”) averaged 267 cpm (SE = 15 cpm), while the healthy sample of this study averaged 428 cpm (SE = 10 cpm). The difference in cpm between the unhealthy and healthy groups is similar between males and females
Roettger, Mayo; Martin, William; Dagan, Tal
2009-09-01
Among the methods currently used in phylogenomic practice to detect the presence of lateral gene transfer (LGT), one of the most frequently employed is the comparison of gene tree topologies for different genes. In cases where the phylogenies for different genes are incompatible, or discordant, for well-supported branches there are three simple interpretations for the result: 1) gene duplications (paralogy) followed by many independent gene losses have occurred, 2) LGT has occurred, or 3) the phylogeny is well supported but for reasons unknown is nonetheless incorrect. Here, we focus on the third possibility by examining the properties of 22,437 published multiple sequence alignments, the Bayesian maximum likelihood trees for which either do or do not suggest the occurrence of LGT by the criterion of discordant branches. The alignments that produce discordant phylogenies differ significantly in several salient alignment properties from those that do not. Using a support vector machine, we were able to predict the inference of discordant tree topologies with up to 80% accuracy from alignment properties alone.
Talley, Amelia E.; Aranda, Frances; Hughes, Tonda L.; Everett, Bethany; Johnson, Timothy P.
2015-01-01
We examined differences between sexual minority women’s (SMW’s) sexual identity and sexual behavior or sexual attraction as potential contributors to hazardous drinking across a 10-year period. Data are from a longitudinal study examining drinking and drinking-related problems in a diverse, community-based sample of self-identified SMW (Wave 1: n = 447; Wave 2: n = 384; Wave 3: n = 354). Longitudinal cross-lagged models showed that SMW who report higher levels of identity-behavior or identity-attraction discordance may be at greater risk of concurrent and subsequent hazardous drinking. Results of multigroup models suggest that sexual orientation discordance is a more potent risk factor for risky drinking outcomes among SMW in older adulthood than in younger adulthood. Findings support that discordance between sexual orientation dimensions may contribute to hazardous drinking among SMW and provide evidence that cognitive-behavioral consistency is important for individuals expressing diverse and fluid sexual identities, attraction, and behavior. PMID:25911224
Discordant sex in monozygotic XXY/XX twins: a case report.
Tachon, G; Lefort, G; Puechberty, J; Schneider, A; Jeandel, C; Boulot, P; Prodhomme, O; Meyer, P; Taviaux, S; Touitou, I; Pellestor, F; Geneviève, D; Gatinois, V
2014-12-01
We report a case of discordant phenotypic sex in monozygotic twins mosaic 47,XXY/46,XX: monozygotic heterokaryotypic twins. The twins presented with cognitive and comprehension delay, behavioural and language disorders, all symptoms frequently reported in Klinefelter syndrome. Molecular zygosity analysis with several markers confirmed that the twins are in effect monozygotic (MZ). Array comparative genomic hybridization found no evidence for the implication of copy number variation in the phenotypes. Ultrasound scans of the reproductive organs revealed no abnormalities. Endocrine tests showed a low testosterone level in Twin 1 (male phenotype) and a low gonadotrophin level in Twin 2 (female phenotype) which, combined with the results from ultrasound examination, provided useful information for potentially predicting the future fertility potential of the twins. Blood karyotypes revealed the presence of a normal 46,XX cell line and an aneuploïd 47,XXY cell line in both patients. Examination of the chromosome constitutions of various tissues such as blood, buccal smear and urinary sediment not surprisingly showed different proportions for the 46,XX and 47,XXY cell lines, which most likely explains the discordant phenotypic sex and mild Klinefelter features. The most plausible underlying biological mechanism is a post-zygotic loss of the Y chromosome in an initially 47,XXY zygote. This would result in an embryo with both 46,XX and 47,XXY cells lines which could subsequently divide into two monozygotic embryos through a twinning process. The two cell lines would then be distributed differently between tissues which could result in phenotypic discordances in the twins. These observations emphasize the importance of regular paediatric evaluations to determine the optimal timing for fertility preservation measures and to detect new Klinefelter features which could appear throughout childhood in the two subjects. © The Author 2014. Published by Oxford University Press on
Mitochondrial DNA Copy Number in Sleep Duration Discordant Monozygotic Twins
Wrede, Joanna E.; Mengel-From, Jonas; Buchwald, Dedra; Vitiello, Michael V.; Bamshad, Michael; Noonan, Carolyn; Christiansen, Lene; Christensen, Kaare; Watson, Nathaniel F.
2015-01-01
Study Objectives: Mitochondrial DNA (mtDNA) copy number is an important component of mitochondrial function and varies with age, disease, and environmental factors. We aimed to determine whether mtDNA copy number varies with habitual differences in sleep duration within pairs of monozygotic twins. Setting: Academic clinical research center. Participants: 15 sleep duration discordant monozygotic twin pairs (30 twins, 80% female; mean age 42.1 years [SD 15.0]). Design: Sleep duration was phenotyped with wrist actigraphy. Each twin pair included a “normal” (7–9 h/24) and “short” (< 7 h/24) sleeping twin. Fasting peripheral blood leukocyte DNA was assessed for mtDNA copy number via the n-fold difference between qPCR measured mtDNA and nuclear DNA creating an mtDNA measure without absolute units. We used generalized estimating equation linear regression models accounting for the correlated data structure to assess within-pair effects of sleep duration on mtDNA copy number. Measurements and Results: Mean within-pair sleep duration difference per 24 hours was 94.3 minutes (SD 62.6 min). We found reduced sleep duration (β = 0.06; 95% CI 0.004, 0.12; P < 0.05) and sleep efficiency (β = 0.51; 95% CI 0.06, 0.95; P < 0.05) were significantly associated with reduced mtDNA copy number within twin pairs. Thus every 1-minute decrease in actigraphy-defined sleep duration was associated with a decrease in mtDNA copy number of 0.06. Likewise, a 1% decrease in actigraphy-defined sleep efficiency was associated with a decrease in mtDNA copy number of 0.51. Conclusions: Reduced sleep duration and sleep efficiency were associated with reduced mitochondrial DNA copy number in sleep duration discordant monozygotic twins offering a potential mechanism whereby short sleep impairs health and longevity through mitochondrial stress. Citation: Wrede JE, Mengel-From J, Buchwald D, Vitiello MV, Bamshad M, Noonan C, Christiansen L, Christensen K, Watson NF. Mitochondrial DNA copy number
Negash, Selam; Wilson, Robert S.; Leurgans, Sue E.; Wolk, David A.; Schneider, Julie A.; Buchman, Aron S.; Bennett, David A.; Arnold, Steven. E.
2014-01-01
Background Although it is now evident that normal cognition can occur despite significant AD pathology, few studies have attempted to characterize this discordance, or examine factors that may contribute to resilient brain aging in the setting of AD pathology. Methods More than 2,000 older persons underwent annual evaluation as part of participation in the Religious Orders Study or Rush Memory Aging Project. A total of 966 subjects who had brain autopsy and comprehensive cognitive testing proximate to death were analyzed. Resilience was quantified as a continuous measure using linear regression modeling, where global cognition was entered as a dependent variable and global pathology was an independent variable. Studentized residuals generated from the model represented the discordance between cognition and pathology, and served as measure of resilience. The relation of resilience index to known risk factors for AD and related variables was examined. Results Multivariate regression models that adjusted for demographic variables revealed significant associations for early life socioeconomic status, reading ability, APOE-ε4 status, and past cognitive activity. A stepwise regression model retained reading level (estimate = 0.10, SE = 0.02; p < 0.0001) and past cognitive activity (estimate = 0.27, SE = 0.09; p = 0.002), suggesting the potential mediating role of these variables for resilience. Conclusions The construct of resilient brain aging can provide a framework for quantifying the discordance between cognition and pathology, and help identify factors that may mediate this relationship. PMID:23919768
Residual depth anomalies and the origin of the Australian-Antarctic discordance zone
NASA Astrophysics Data System (ADS)
Marks, Karen M.; Vogt, Peter R.; Hall, Stuart A.
1990-10-01
A new, high resolution depth anomaly map covering the anomalously deep and rough Australian-Antarctic Discordance (AAD) has been constructed using crustal ages derived from a detailed aeromagnetic survey. The map shows a large, arcuate-shaped, negative depth anomaly that is centered on the Southeast Indian Ridge and trends NNE across the Australian plate (SSE across the Antarctic plate). Within this broad scale feature, two prominent depth anomaly lows are observed at 45°S, 128°E (the northern flank) and 54°S, 125°E (the southern flank). Both lows are associated with 15 Ma oceanic crust. The observed depth anomaly patterns are compared with the distinctive patterns predicted by coldspot, downwelling limbs of convection cells, and thin crust models of the discordance source. The observed depth anomaly does not result from absolute plate motions over a fixed coldspot source because the predicted ENE trend on the Antarctic plate is not in agreement with the SSE trend observed. The symmetric arrangement of the large-scale depth anomaly and prominent lows about the ridge axis suggests instead a source that has varied in strength but remained located at the ridge axis as the ridge migrated northeastward in the absolute reference frame. The organized pattern of elongated depth anomaly highs and lows predicted for upper mantle convection (cells) is not evident in the observed depth anomaly map. Thus a convergence of downwelling limbs of convection cells beneath the discordance is not indicated. If the source of cooler upwelling that produces less magma and hence thin crust has not varied over time, nor migrated along the ridge, then the predicted depth anomaly would persist unchanged with distance from the ridge axis, and trend in the direction of relative plate motion (parallel to fracture zones). The observed depth anomaly trends obliquely across fracture zones and changes in both amplitude and location relative to the ridge axis, and is therefore not consistent with
Saravanan, Shanmugam; Gomathi, Selvamurthi; Delong, Allison; Kausalya, Bagavathi; Sivamalar, Sathasivam; Poongulali, Selvamuthu; Brooks, Katherine; Kumarasamy, Nagalingeswaran; Balakrishnan, Pachamuthu; Solomon, Sunil S; Cu-Uvin, Susan; Kantor, Rami
2018-05-24
Examine HIV-1 plasma viral load (PVL) and genital tract (GT) viral load (GVL) and drug resistance in India. At the YRG Centre for AIDS Research and Education, Chennai, we tested: PVL in women on first-line ART for ≥6 months; GVL when PVL >2000 copies/mL; and plasma, genital and proviral reverse transcriptase drug resistance when GVL >2000 copies/mL. Wilcoxon rank-sum and Fisher's exact tests were used to identify failure and resistance associations. Pearson correlations were calculated to evaluate PVL-GVL associations. Inter-compartmental resistance discordance was evaluated using generalized estimating equations. Of 200 women, 37% had detectable (>400 copies/mL) PVL and 31% had PVL >1000 copies/mL. Of women with detectable PVL, 74% had PVL >2000 copies/mL, of which 74% had detectable GVL. Higher PVL was associated with higher GVL. Paired plasma and genital sequences were available for 21 women; mean age of 34 years, median ART duration of 33 months, median CD4 count of 217 cells/mm3, median PVL of 5.4 log10 copies/mL and median GVL of 4.6 log10 copies/mL. Drug resistance was detected in 81%-91% of samples and 67%-76% of samples had dual-class resistance. Complete three-compartment concordance was seen in only 10% of women. GT-proviral discordance was significantly larger than plasma-proviral discordance. GT or proviral mutations discordant from plasma led to clinically relevant resistance in 24% and 30%, respectively. We identified high resistance and high inter-compartmental resistance discordance in Indian women, which might lead to unrecognized resistance transmission and re-emergence compromising treatment outcomes, particularly relevant to countries like India, where sexual HIV transmission is predominant.
Theoretical investigations of quantum correlations in NMR multiple-pulse spin-locking experiments
NASA Astrophysics Data System (ADS)
Gerasev, S. A.; Fedorova, A. V.; Fel'dman, E. B.; Kuznetsova, E. I.
2018-04-01
Quantum correlations are investigated theoretically in a two-spin system with the dipole-dipole interactions in the NMR multiple-pulse spin-locking experiments. We consider two schemes of the multiple-pulse spin-locking. The first scheme consists of π /2-pulses only and the delays between the pulses can differ. The second scheme contains φ-pulses (0<φ <π ) and has equal delays between them. We calculate entanglement for both schemes for an initial separable state. We show that entanglement is absent for the first scheme at equal delays between π /2-pulses at arbitrary temperatures. Entanglement emerges after several periods of the pulse sequence in the second scheme at φ =π /4 at milliKelvin temperatures. The necessary number of the periods increases with increasing temperature. We demonstrate the dependence of entanglement on the number of the periods of the multiple-pulse sequence. Quantum discord is obtained for the first scheme of the multiple-pulse spin-locking experiment at different temperatures.
Asymmetry and discordance for congenital anomalies in conjoined twins: a report of six cases.
Ornoy, A; Navot, D; Menashi, M; Laufer, N; Chemke, J
1980-10-01
Six pairs of conjoined twins have been studied. The first case was a pair of 13-week-old omphalopagus fetuses. One was a holoacradius amorphus and the other had rachischisis and anencephaly. The second case was a pair of omphalopagus twins. One of the twins was macerated and corresponded to a developmental age of 13-14 weeks, while the other was developed to 28-30 weeks of gestation and exhibited urogenital and gastrointestinal defects not found in the smaller twin. In the third case, that of a thoracoomphalopagus, one had cleft lip and palate, pulmonic stenosis, and atresia of the ileocecal valve, while the other did not show these anomalies. In the fourth cae, also omphalopagus twins, one had a lumbosacral meningomyelocele and severe gastrointestinal and urogenital anomalies not found in the second twin. The fifth case was a pair of thoracoomphalopagus twins, sharing a common heart with asymmetrical anomalies. The sixth case was a diprosopus anencephalic conjoined twin. The first pairs of conjoined twins were discordant for several abnormalities in nonshared organs, in addition to having abnormalities of the conjoined organs. It seems that discordance in conjoined twins is not a rare finding. The factors that play a role in discordance of anomalies in conjoined twins are probably similar to the factors in monozygotic twins--i.e., environmental, genetic, and abnormal placental and/or fetal circulation.
NASA Astrophysics Data System (ADS)
Arthur, Tsamouo Tsokeng; Martin, Tchoffo; Fai, Lukong Cornelius
2018-06-01
We investigate the dynamics of entanglement, decoherence and quantum discord in a system of three non-interacting superconducting flux qubits (fqubits) initially prepared in a Greenberger-Horne-Zeilinger (GHZ) state and subject to static noise in different, bipartite and common environments, since it is recognized that different noise configurations generally lead to completely different dynamical behavior of physical systems. The noise is modeled by randomizing the single fqubit transition amplitude. Decoherence and quantum correlations dynamics are strongly affected by the purity of the initial state, type of system-environment interaction and the system-environment coupling strength. Specifically, quantum correlations can persist when the fqubits are commonly coupled to a noise source, and reaches a saturation value respective to the purity of the initial state. As the number of decoherence channels increases (bipartite and different environments), decoherence becomes stronger against quantum correlations that decay faster, exhibiting sudden death and revival phenomena. The residual entanglement can be successfully detected by means of suitable entanglement witness, and we derive a necessary condition for entanglement detection related to the tunable and non-degenerated energy levels of fqubits. In accordance with the current literature, our results further suggest the efficiency of fqubits over ordinary ones, as far as the preservation of quantum correlations needed for quantum processing purposes is concerned.
Jo, Yong Suk; Park, Ju-Hee; Lee, Jung Kyu; Heo, Eun Young; Chung, Hee Soon; Kim, Deog Kyeom
2016-01-01
The prevalence and clinical implications of discordance between Xpert MTB/RIF assays and the AdvanSure TB/NTM real-time polymerase chain reaction (PCR) for bronchial washing specimens have not been studied in pulmonary TB (PTB) patients. The discordant proportion and its clinical impact were evaluated in 320 patients from the bronchoscopy registry whose bronchial washing specimens were tested simultaneously with Xpert MTB/RIF and the TB/NTM PCR assay for three years, and the accuracy of the assays, including the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV), were studied. The clinical risk factors for discordance and false positivity of assays were also studied. Among 130 patients who were clinically diagnosed with PTB, 64 patients showed positive acid-fast bacilli culture results, 56 patients showed positive results in molecular methods and clinician diagnosed PTB without results of microbiology in 10 patients. The sensitivity, specificity, PPV, and NPV were 80.0%, 98.95%, 98.1%, and 87.9%, respectively, for Xpert MTB/RIF and 81.5%, 92.6%, 88.3%, and 88.0%, respectively, for TB/NTM PCR. The discordant proportion was 16.9% and was higher in culture-negative PTB compared to culture-confirmed PTB (24.3% vs. 9.4%, p = 0.024). However, there were no significant differences in the clinical characteristics, regardless of the discordance. The diagnostic yield increased with an additional assay (7.7% for Xpert MTB/RIF and 9.2% for TB/NTM PCR). False positivity was less common in patients tested with Xpert MTB/RIF (1.05% vs. 7.37%, p = 0.0035). No host-related risk factor for false positivity was identified. The Xpert MTB/RIF and TB/NTM PCR assay in bronchial washing specimens can improve the diagnostic yields for PTB, although there were considerable discordant results without any patient-related risk factors.
Bondia-Pons, Isabel; Maukonen, Johanna; Mattila, Ismo; Rissanen, Aila; Saarela, Maria; Kaprio, Jaakko; Hakkarainen, Antti; Lundbom, Jesper; Lundbom, Nina; Hyötyläinen, Tuulia; Pietiläinen, Kirsi H; Orešič, Matej
2014-09-01
Postprandial responses to food are complex, involving both genetic and environmental factors. We studied postprandial responses to a Big Mac meal challenge in monozygotic co-twins highly discordant for body weight. This unique design allows assessment of the contribution of obesity, independent of genetic liability. Comprehensive metabolic profiling using 3 analytical platforms was applied to fasting and postprandial serum samples from 16 healthy monozygotic twin pairs discordant for weight (body mass index difference >3 kg/m(2)). Nine concordant monozygotic pairs were examined as control pairs. Fecal samples were analyzed to assess diversity of the major bacterial groups by using 5 different validated bacterial group specific denaturing gradient gel electrophoresis methods. No differences in fecal bacterial diversity were detected when comparing co-twins discordant for weight (ANOVA, P<0.05). We found that within-pair similarity is a dominant factor in the metabolic postprandial response, independent of acquired obesity. Branched chain amino acids were increased in heavier as compared with leaner co-twins in the fasting state, but their levels converged postprandially (paired t tests, FDR q<0.05). We also found that specific bacterial groups were associated with postprandial changes of specific metabolites. Our findings underline important roles of genetic and early life factors in the regulation of postprandial metabolite levels. © FASEB.
Cherla, Deepa V; Olavarria, Oscar A; Holihan, Julie L; Viso, Cristina Perez; Hannon, Craig; Kao, Lillian S; Ko, Tien C; Liang, Mike K
2017-10-01
The Open Payments Database (OPD) discloses financial transactions between manufacturers and physicians. The concordance of OPD versus self-reported conflicts of interest (COI) is unknown. Our objectives were to compare (1) industry and self-disclosed COI in clinical literature, (2) payments within each disclosure level, and (3) industry- and self-disclosed COI and payments by specialty. This was an observational study. PubMed was searched for clinical studies accepted for publication from January 2014 to June 2016. Author and OPD-disclosed COIs were compared. Articles and authors were divided into full disclosure, incomplete industry disclosure, incomplete self-disclosure, and no COI. Primary outcome (differences in reported COI per article) was assessed using McNemar's test. Payment differences were compared using Kruskal-Wallis test. OPD- and self-disclosed COI differed (65.0% discordance rate by article, P < 0.001). Percentages of authors within each disclosure category differed between specialties (P < 0.001). Hematology articles exhibited the highest discordance rate (79.0%) and received the highest median payment for incomplete self-disclosure ($30,812). Significant discordance exists between self- and OPD-reported COI. Additional research is needed to determine reasons for these differences. Copyright © 2017 Elsevier Inc. All rights reserved.
Moos, Rudolf H.; Schutte, Kathleen K.; Brennan, Penny L.; Moos, Bernice S.
2010-01-01
Aims This study compares the personal, family, and social functioning of older husbands and wives concordant or discordant for high-risk alcohol consumption and identifies predictors of changes in concordance and high-risk consumption. Design, Participants, Measurements Three groups of couples were identified at baseline and followed 10 years later: (1) concordant couples in which husbands and wives engaged in low-risk alcohol consumption (N = 54), (2) concordant couples in which husbands and wives engaged in high-risk alcohol consumption (N = 38), and (3) discordant couples in which one partner engaged in high-risk alcohol consumption and the other partner did not (N = 75). At each follow-up, husbands and wives completed an inventory that assessed their personal, family, and social functioning. Findings Compared to the low-risk concordant group, husbands and wives in the high-risk concordant group were more likely to rely on tension-reduction coping, reported more friend approval of drinking, and were less involved in religious activities; however, they did not differ in the quality of the spousal relationship. The frequency of alcohol consumption declined among husbands in discordant couples, but not among husbands in concordant couples. Predictors of high-risk drinking included tension-reduction coping, friend approval of drinking, and, for husbands, their wives’ level of drinking. Conclusions High-risk and discordant alcohol consumption do not seem to be linked to decrements in family functioning among older couples in long-term stable marriages. The predictors of heavy alcohol consumption among older husbands and wives identify points of intervention that may help to reduce their high-risk drinking. PMID:20883458
Moos, Rudolf H; Schutte, Kathleen K; Brennan, Penny L; Moos, Bernice S
2011-02-01
This study compares the personal, family and social functioning of older husbands and wives concordant or discordant for high-risk alcohol consumption and identifies predictors of changes in concordance and high-risk consumption. Three groups of couples were identified at baseline and followed 10 years later: (i) concordant couples in which husbands and wives engaged in low-risk alcohol consumption (n = 54); (ii) concordant couples in which husbands and wives engaged in high-risk alcohol consumption (n = 38); and (iii) discordant couples in which one partner engaged in high-risk alcohol consumption and the other partner did not (n = 75). At each follow-up, husbands and wives completed an inventory that assessed their personal, family and social functioning. Compared to the low-risk concordant group, husbands and wives in the high-risk concordant group were more likely to rely on tension-reduction coping, reported more friend approval of drinking, and were less involved in religious activities; however, they did not differ in the quality of the spousal relationship. The frequency of alcohol consumption declined among husbands in discordant couples, but not among husbands in concordant couples. Predictors of high-risk drinking included tension-reduction coping, friend approval of drinking and, for husbands, their wives' level of drinking. High-risk and discordant alcohol consumption do not seem to be linked to decrements in family functioning among older couples in long-term stable marriages. The predictors of heavy alcohol consumption among older husbands and wives identify points of intervention that may help to reduce their high-risk drinking. © 2010 Society for the Study of Addiction. No claim to US government works.
Soh, Jason; Rositch, Anne F.; Koutsky, Laura; Guthrie, Brandon L.; Choi, Robert Y.; Bosire, Rose K.; Gatuguta, Ann; Smith, Jennifer S.; Kiarie, James; Lohman-Payne, Barbara; Farquhar, Carey
2014-01-01
Individual and sexual partner characteristics may increase risk of abnormal cervical cytology among women in HIV-discordant relationships. Papanicolaou smears were obtained in a prospective cohort of Kenyan HIV-discordant couples. Of 441 women, 283 (64%) were HIV-infected and 158 (36%) were HIV-uninfected with HIV-infected partners. Overall, 79 (18%) had low-grade and 25 (6%) high-grade cervical abnormalities. Lack of male circumcision, male HSV-2 seropositivity and lower couple socioeconomic status were associated with cervical abnormalities (p<0.05). HIV-uninfected women with HIV-infected male sex partners (CD4>350 cells/µL) had the lowest prevalence of high-grade cervical lesions. HIV-infected women (CD4>350 cells/µL) and HIV-uninfected women with HIV-infected partners (CD4≤350 cells/µL) were at similar intermediate risk (P>0.05), and HIV-infected women (CD4≤350 cells/µL) had significantly higher risk of high-grade cervical abnormalities (p=0.05). Women in HIV-discordant relationships have high rates of cervical lesions and this may be influenced by couple-level factors, including HIV status and CD4 count of the infected partner. PMID:24047885
Comparison of Genomic and Epigenomic Expression in Monozygotic Twins Discordant for Rett Syndrome
Kunio, Miyake; Yang, Chunshu; Minakuchi, Yohei; Ohori, Kenta; Soutome, Masaki; Hirasawa, Takae; Kazuki, Yasuhiro; Adachi, Noboru; Suzuki, Seiko; Itoh, Masayuki; Goto, Yu-ichi; Andoh, Tomoko; Kurosawa, Hiroshi; Akamatsu, Wado; Ohyama, Manabu; Okano, Hideyuki; Oshimura, Mitsuo; Sasaki, Masayuki; Toyoda, Atsushi; Kubota, Takeo
2013-01-01
Monozygotic (identical) twins have been widely used in genetic studies to determine the relative contributions of heredity and the environment in human diseases. Discordance in disease manifestation between affected monozygotic twins has been attributed to either environmental factors or different patterns of X chromosome inactivation (XCI). However, recent studies have identified genetic and epigenetic differences between monozygotic twins, thereby challenging the accepted experimental model for distinguishing the effects of nature and nurture. Here, we report the genomic and epigenomic sequences in skin fibroblasts of a discordant monozygotic twin pair with Rett syndrome, an X-linked neurodevelopmental disorder characterized by autistic features, epileptic seizures, gait ataxia and stereotypical hand movements. The twins shared the same de novo mutation in exon 4 of the MECP2 gene (G269AfsX288), which was paternal in origin and occurred during spermatogenesis. The XCI patterns in the twins did not differ in lymphocytes, skin fibroblasts, and hair cells (which originate from ectoderm as does neuronal tissue). No reproducible differences were detected between the twins in single nucleotide polymorphisms (SNPs), insertion-deletion polymorphisms (indels), or copy number variations. Differences in DNA methylation between the twins were detected in fibroblasts in the upstream regions of genes involved in brain function and skeletal tissues such as Mohawk Homeobox (MKX), Brain-type Creatine Kinase (CKB), and FYN Tyrosine Kinase Protooncogene (FYN). The level of methylation in these upstream regions was inversely correlated with the level of gene expression. Thus, differences in DNA methylation patterns likely underlie the discordance in Rett phenotypes between the twins. PMID:23805272
Comparison of Genomic and Epigenomic Expression in Monozygotic Twins Discordant for Rett Syndrome.
Miyake, Kunio; Yang, Chunshu; Minakuchi, Yohei; Ohori, Kenta; Soutome, Masaki; Hirasawa, Takae; Kazuki, Yasuhiro; Adachi, Noboru; Suzuki, Seiko; Itoh, Masayuki; Goto, Yu-Ichi; Andoh, Tomoko; Kurosawa, Hiroshi; Oshimura, Mitsuo; Sasaki, Masayuki; Toyoda, Atsushi; Kubota, Takeo
2013-01-01
Monozygotic (identical) twins have been widely used in genetic studies to determine the relative contributions of heredity and the environment in human diseases. Discordance in disease manifestation between affected monozygotic twins has been attributed to either environmental factors or different patterns of X chromosome inactivation (XCI). However, recent studies have identified genetic and epigenetic differences between monozygotic twins, thereby challenging the accepted experimental model for distinguishing the effects of nature and nurture. Here, we report the genomic and epigenomic sequences in skin fibroblasts of a discordant monozygotic twin pair with Rett syndrome, an X-linked neurodevelopmental disorder characterized by autistic features, epileptic seizures, gait ataxia and stereotypical hand movements. The twins shared the same de novo mutation in exon 4 of the MECP2 gene (G269AfsX288), which was paternal in origin and occurred during spermatogenesis. The XCI patterns in the twins did not differ in lymphocytes, skin fibroblasts, and hair cells (which originate from ectoderm as does neuronal tissue). No reproducible differences were detected between the twins in single nucleotide polymorphisms (SNPs), insertion-deletion polymorphisms (indels), or copy number variations. Differences in DNA methylation between the twins were detected in fibroblasts in the upstream regions of genes involved in brain function and skeletal tissues such as Mohawk Homeobox (MKX), Brain-type Creatine Kinase (CKB), and FYN Tyrosine Kinase Protooncogene (FYN). The level of methylation in these upstream regions was inversely correlated with the level of gene expression. Thus, differences in DNA methylation patterns likely underlie the discordance in Rett phenotypes between the twins.
Graphic and algebraic solutions of the discordant lead-uranium age problem
Stieff, L.R.; Stern, T.W.
1961-01-01
Uranium-bearing minerals that give lead-uranium and lead-lead ages that are essentially in agreement, i.e. concordant, generally are considered to have had a relatively simple geologic history and to have been unaltered since their deposition. The concordant ages obtained on such materials are, therefore, assumed to approach closely the actual age of the minerals. Many uranium-bearing samples, particularly uranium ores, give the following discordant age sequences; Pb206 U238 < Pb207 U235 ??? Pb207 Pb206 or, less frequently, Pb207 Pb206 ??? Pb207 U235 < Pb206 U238. These discordant age sequences have been attributed most often to uncertainties in the common lead correction, selective loss of radio-active daughter products, loss or gain of lead or uranium, or contamination by an older generation of radiogenic lead. The evaluation of discordant lead isotope age data may be separated into two operations. The first operation, with which this paper is concerned, is mechanical in nature and involves the calculation of the different possible concordant ages corresponding to the various processes assumed to have produced the discordant ages. The second operation is more difficult to define and requires, in part, some personal judgement. It includes a synthesis of the possible concordant age solutions with other independent geologic and isotopic evidence. The concordant age ultimately chosen as most acceptable should be consistent not only with the known events in the geologic history of the area, the age relations of the enclosing rocks, and the mineralogic and paragenetic evidence, but also with other independent age measurements and the isotopic data obtained on the lead in related or associated non-radioactive minerals. The calculation of the possible concordant ages from discordant age data has been greatly simplified by Wetherill's graphical method of plotting the mole ratios of radiogenic Pb206 U238 ( N206 N238) vs. radiogenic Pb207 U235 ( N207 N235) after correcting
Anxiety Disorders and Latinos: The Role of Family Cohesion and Family Discord
ERIC Educational Resources Information Center
Priest, Jacob B.; Denton, Wayne
2012-01-01
Family cohesion has shown to be associated with lower psychological distress and other risk behaviors for Latinos, but little is known about the relationship of family cohesion, family discord, and anxiety disorders. Using data from the National Latino and Asian American Study (n = 2,554), this study examines the relationship between family…
Physician Racial Bias and Word Use during Racially Discordant Medical Interactions.
Hagiwara, Nao; Slatcher, Richard B; Eggly, Susan; Penner, Louis A
2017-04-01
Physician racial bias can negatively affect Black patients' reactions to racially discordant medical interactions, suggesting that racial bias is manifested in physicians' communication with their Black patients. However, little is known about how physician racial bias actually influences their communication during these interactions. This study investigated how non-Black physicians' racial bias is related to their word use during medical interactions with Black patients. One hundred and seventeen video-recorded racially discordant medical interactions from a larger study were transcribed and analyzed using Linguistic Inquiry and Word Count (LIWC) software. Physicians with higher levels of implicit racial bias used first-person plural pronouns and anxiety-related words more frequently than physicians with lower levels of implicit bias. There was also a trend for physicians with higher levels of explicit racial bias to use first-person singular pronouns more frequently than physicians with lower levels of explicit bias. These findings suggest that non-Black physicians with higher levels of implicit racial bias may tend to use more words that reflect social dominance (i.e., first-person plural pronouns) and anxiety when interacting with Black patients.
Physician Racial Bias and Word Use during Racially Discordant Medical Interactions
Hagiwara, Nao; Slatcher, Richard B.; Eggly, Susan; Penner, Louis A.
2016-01-01
Physician racial bias can negatively affect Black patients’ reactions to racially discordant medical interactions, suggesting that racial bias is manifested in physicians’ communication with their Black patients. However, little is known about how physician racial bias actually influences their communication during these interactions. This study investigated how non-Black physicians’ racial bias is related to their word use during medical interactions with Black patients. One hundred and seventeen video-recorded racially discordant medical interactions from a larger study were transcribed and analyzed using Linguistic Inquiry and Word Count (LIWC) software. Physicians with higher levels of implicit racial bias used first-person plural pronouns and anxiety-related words more frequently than physicians with lower levels of implicit bias. There was also a trend for physicians with higher levels of explicit racial bias to use first-person singular pronouns more frequently than physicians with lower levels of explicit bias. These findings suggest that non-Black physicians with higher levels of implicit racial bias may tend to use more words that reflect social dominance (i.e., first-person plural pronouns) and anxiety when interacting with Black patients. PMID:27309596
Cold Pressor Pain Sensitivity in Twins Discordant for Chronic Fatigue Syndrome
Ullrich, Phil; Afari, Niloofar; Jacobsen, Clemma; Goldberg, Jack; Buchwald, Dedra
2010-01-01
Objective Individuals with chronic fatigue syndrome (CFS) experience many pain symptoms. The present study examined whether pain and fatigue ratings and pain threshold and tolerance levels for cold pain differed between twins with CFS and their cotwins without CFS. Design Cotwin control design to assess cold pain sensitivity, pain, and fatigue in monozygotic twins discordant for CFS. Patients and Setting Fifteen twin pairs discordant for CFS recruited from the volunteer Chronic Fatigue Twin Registry at the University of Washington. Results Although cold pain threshold and tolerance levels were slightly lower in twins with CFS than their cotwins without CFS, these differences failed to reach statistical significance. Subjective ratings of pain and fatigue at multiple time points during the experimental protocol among twins with CFS were significantly higher than ratings of pain (p = 0.003) and fatigue (p < 0.001) by their cotwins without CFS. Conclusions These results, while preliminary, highlight the perceptual and cognitive components to the pain experience in CFS. Future studies should focus on examining the heritability of pain sensitivity and the underlying mechanisms involved in the perception of pain sensitivity in CFS. PMID:17371408
Changes in children's appraisals of marital discord from childhood through adolescence.
Richmond, Melissa K; Stocker, Clare M
2007-09-01
The study examined how children's appraisals of marital conflict (threat and self-blame) changed across development, whether changes in exposure to marital conflict were associated with corresponding changes in appraisals, and whether the appraisal process was different for boys and girls. Data were collected on 112 families (224 children) at 4 time points. At each wave, children (mean ages ranged from 8 to 19) provided information on their appraisals of marital conflict, and parents provided information on children's exposure to marital conflict. Results indicated that appraisals of threat declined rapidly from childhood to adolescence and then declined less rapidly across adolescence; appraisals of self-blame showed little change over time. Second, changes in exposure to marital discord covaried with changes in threat over time, but not with changes in self-blame. Finally, boys experienced more self-blame than girls on average, and gender moderated the association between exposure to marital discord and threat. Results suggest that development, exposure to marital conflict, and gender are important in determining why some children appraise their parents' disputes negatively. PsycINFO Database Record (c) 2007 APA, all rights reserved
Antiretroviral Therapy Reduces HIV Transmission in Discordant Couples in Rural Yunnan, China
He, Na; Duan, Song; Ding, Yingying; Rou, Keming; McGoogan, Jennifer M.; Jia, Manhong; Yang, Yuecheng; Wang, Jibao; Montaner, Julio S. G.; Wu, Zunyou
2013-01-01
Background Although HIV treatment as prevention (TasP) via early antiretroviral therapy (ART) has proven to reduce transmissions among HIV-serodiscordant couples, its full implementation in developing countries remains a challenge. In this study, we determine whether China's current HIV treatment program prevents new HIV infections among discordant couples in rural China. Methods A prospective, longitudinal cohort study was conducted from June 2009 to March 2011, in rural Yunnan. A total of 1,618 HIV-discordant couples were eligible, 1,101 were enrolled, and 813 were followed for an average of 1.4 person-years (PY). Routine ART was prescribed to HIV-positive spouses according to eligibility (CD4<350 cells/µl). Seroconversion was used to determine HIV incidence. Results A total of 17 seroconversions were documented within 1,127 PY of follow-up, for an overall incidence of 1.5 per 100 PY. Epidemiological and genetic evidence confirmed that all 17 seroconverters were infected via marital secondary sexual transmission. Having an ART-experienced HIV-positive partner was associated with a lower rate of seroconvertion compared with having an ART-naïve HIV-positive partner (0.8 per 100 PY vs. 2.4 per 100 PY, HR = 0.34, 95%CI = 0.12–0.97, p = 0.0436). While we found that ART successfully suppressed plasma viral load to <400 copies/ml in the majority of cases (85.0% vs. 19.5%, p<0.0001 at baseline), we did document five seroconversions among ART-experienced subgroup. Conclusions ART is associated with a 66% reduction in HIV incidence among discordant couples in our sample, demonstrating the effectiveness of China's HIV treatment program at preventing new infections, and providing support for earlier ART initiation and TasP implementation in this region. PMID:24236010
[Analysis for Discordance of Positive and Negative Blood Typing by Gel Card].
Li, Cui-Ying; Xu, Hong; Lei, Hui-Fen; Liu, Juan; Li, Xiao-Wei
2017-08-01
To explore the method of Gel card identifying ABO blood group, determine the inconsistent cause and the distribution of disease affecting factors, and put forward a method of its solutions. To collect 240 positive and negative typing-discordant blood speciments from patients examined by Gel card and send these speciments to blood type reference laboratory for examining with the classic tube method and serological test, such as salivary blood-group substance, in order to performe genotyping method when serologic test can not be determined. Among 240 positive and negative typing-discordant blood speciments from patients examined by Gel card, 107 blood speciments were positive and negative consistent examined by false agglutination test (44.58%), 133 blood specinents were discordent examined by false agglutination (55.42%), out of them, 35 cases (14.58%) with inconsistent cold agglutination test, 22 cases (9.17%) with weakened AB antigenicity, 16 cases (6.67%) with ABO subtyping, 12 cases (5.00%) with positive direct antiglobulin test, 11 cases (4.58%) with reduced or without antibodies, 11 cases (4.58%) with false aggregation caused by drugs or protein, 11 cases (4.58%) with salivary blood-type substances, 8 cases (3.33%) with non-ABO alloantibody, and 7 cases (2.92%) with allogeneic bone marrow transplantation. The distribution of disease were following: blood disease (16.83%), tumor (11.88%), and cardiopulmonary diseases (11.39%); chi-square test results indicated that the distribution significantly different. The analysis of ABO blood grouping shows a variety factors influencing positive and negative blood typing, and the Gel Card identification can produc more false positive blood types. Therefore, more attention should be paid on the high incidence diseases, such as blood disease, tumor, and cardiopulmonary disease.
Extensive gene tree discordance and hemiplasy shaped the genomes of North American columnar cacti.
Copetti, Dario; Búrquez, Alberto; Bustamante, Enriquena; Charboneau, Joseph L M; Childs, Kevin L; Eguiarte, Luis E; Lee, Seunghee; Liu, Tiffany L; McMahon, Michelle M; Whiteman, Noah K; Wing, Rod A; Wojciechowski, Martin F; Sanderson, Michael J
2017-11-07
Few clades of plants have proven as difficult to classify as cacti. One explanation may be an unusually high level of convergent and parallel evolution (homoplasy). To evaluate support for this phylogenetic hypothesis at the molecular level, we sequenced the genomes of four cacti in the especially problematic tribe Pachycereeae, which contains most of the large columnar cacti of Mexico and adjacent areas, including the iconic saguaro cactus ( Carnegiea gigantea ) of the Sonoran Desert. We assembled a high-coverage draft genome for saguaro and lower coverage genomes for three other genera of tribe Pachycereeae ( Pachycereus , Lophocereus , and Stenocereus ) and a more distant outgroup cactus, Pereskia We used these to construct 4,436 orthologous gene alignments. Species tree inference consistently returned the same phylogeny, but gene tree discordance was high: 37% of gene trees having at least 90% bootstrap support conflicted with the species tree. Evidently, discordance is a product of long generation times and moderately large effective population sizes, leading to extensive incomplete lineage sorting (ILS). In the best supported gene trees, 58% of apparent homoplasy at amino sites in the species tree is due to gene tree-species tree discordance rather than parallel substitutions in the gene trees themselves, a phenomenon termed "hemiplasy." The high rate of genomic hemiplasy may contribute to apparent parallelisms in phenotypic traits, which could confound understanding of species relationships and character evolution in cacti. Published under the PNAS license.
Extensive gene tree discordance and hemiplasy shaped the genomes of North American columnar cacti
Búrquez, Alberto; Bustamante, Enriquena; Charboneau, Joseph L. M.; Childs, Kevin L.; Eguiarte, Luis E.; Lee, Seunghee; Liu, Tiffany L.; McMahon, Michelle M.; Whiteman, Noah K.; Wing, Rod A.; Wojciechowski, Martin F.; Sanderson, Michael J.
2017-01-01
Few clades of plants have proven as difficult to classify as cacti. One explanation may be an unusually high level of convergent and parallel evolution (homoplasy). To evaluate support for this phylogenetic hypothesis at the molecular level, we sequenced the genomes of four cacti in the especially problematic tribe Pachycereeae, which contains most of the large columnar cacti of Mexico and adjacent areas, including the iconic saguaro cactus (Carnegiea gigantea) of the Sonoran Desert. We assembled a high-coverage draft genome for saguaro and lower coverage genomes for three other genera of tribe Pachycereeae (Pachycereus, Lophocereus, and Stenocereus) and a more distant outgroup cactus, Pereskia. We used these to construct 4,436 orthologous gene alignments. Species tree inference consistently returned the same phylogeny, but gene tree discordance was high: 37% of gene trees having at least 90% bootstrap support conflicted with the species tree. Evidently, discordance is a product of long generation times and moderately large effective population sizes, leading to extensive incomplete lineage sorting (ILS). In the best supported gene trees, 58% of apparent homoplasy at amino sites in the species tree is due to gene tree-species tree discordance rather than parallel substitutions in the gene trees themselves, a phenomenon termed “hemiplasy.” The high rate of genomic hemiplasy may contribute to apparent parallelisms in phenotypic traits, which could confound understanding of species relationships and character evolution in cacti. PMID:29078296
Hydrodynamics of concordant and discordant fixed bed open-channel confluences
NASA Astrophysics Data System (ADS)
Birjukova Canelas, Olga; Lage Ferreira, Rui Miguel; Heleno Cardoso, António
2017-04-01
The detailed characterization of the flow field in river confluences constitutes a relevant step towards the understanding of the hydro-morpho-dynamics of these key zones of the fluvial system. With a few exceptions, existing works on this topic covered concordant bed scenarios, meaning that both confluent channels had the same elevation. This laboratory study aims to contribute to a detailed three-dimensional characterization of the flow field at a fixed bed confluence, as well as to shed light on how bed elevation discordance modifies the flow patterns of the converging flows. While the junction angle and the discharge ratio were kept fixed, two scenarios were studied on the basis of detailed water level and 3D ADV measurements at the denser mesh ever. The internal flow structure of the concordant bed scenario mostly complied with the classical conceptual models. A relevant difference concerns the size of the stagnation zone, much smaller close to the bed of the discordant bed confluence. A more significant difference is a horizontal flow structure, not previously identified in the literature, characterized by strong streamwise mean vorticity and strong secondary motion. It is observed for the discordant bed case, occurring along the inner wall of the main channel and downstream the junction corner. This structure is spatially well-correlated to a pronounced imbalance of cross-stream and vertical normal Reynolds stresses. This highlights the role of Reynolds stress anisotropy (RSA) that is generated in the shear layers than accompany the entrance of the tributary flow. Since this structure is not present in the concordant case, where RSA is also evident, it is argued that convective effects should also play a role in its formation, presumably due to deflection of the flow in the main channel by the tributary. The newly identified secondary motion should, thus, be a combination of Prandtĺs second kind and Prandtĺs first kind of secondary flow. The relative
Weinfurter, P; Blumberg, H M; Goldbaum, G; Royce, R; Pang, J; Tapia, J; Bethel, J; Mazurek, G H; Toney, S; Albalak, R
2011-08-01
Persons in whom targeted testing for latent tuberculosis infection (LTBI) is recommended in Seattle, Washington; Atlanta, Georgia; and central North Carolina, United States. To compare the performance of an interferon-gamma release assay (QuantiFERON®-TB Gold In-Tube [QFT-GIT]) with the tuberculin skin test (TST) among foreign-born, homeless, human immunodeficiency virus (HIV) infected and substance abuse persons tested for LTBI. A cross-sectional study requiring participants to have a blood test, a TST and data collected. Of 1653 persons, 19.5% were TST-positive and 14.0% were QFT-GIT-positive. Overall concordance was moderate (kappa 0.53; 95%CI 0.47-0.58). Compared to concordant positive results, TST+/QFT-GIT- discordance was associated with HIV infection and sex, while TST-/QFT-GIT+ discordance was associated with HIV and inversely associated with foreign birth. Compared to concordant negative results, TST-/QFT-GIT+ discordance was associated with foreign birth and age ≥50 years, while TST+/QFT-GIT-discordance was associated with foreign birth, age 30-49 years, being Black and inversely associated with HIV. HIV infection was significantly associated with indeterminate QFT-GIT results. QFT-GIT may be an improvement over the TST for diagnosing LTBI in foreign-born and older persons, and may be as useful as the TST in HIV-infected persons. The sensitivity of both tests may be low in HIV-infected persons.
Savasi, Valeria; Oneta, Monica; Parrilla, Bina; Cetin, Irene
2013-04-01
The debate on HCV discordant couples requiring assisted reproduction is still open today, and specific guidelines have not yet been established on whether or not physicians should treat HCV discordant couples who require ART. We studied the results of our reproductive assistance with sperm washing in HCV discordant couples, all treated in a single center, including the serological status of mothers and babies, and the outcome of the pregnancies. Prospective study conducted between January 2008 and December 2010 in our Reproductive Center in Sacco Hospital, University of Milan. Thirty-five HCV serodiscordant infertile couples with an HCV viremic positive male partner were enrolled. All of them completed the immuno-virological and fertility triage, and were treated according to our clinical protocols. Forty-seven superovulation and IUI and 38 second-level ART procedures are reported. The pregnancy rates for IUI and ICSI are similar to those reported by the Italian ART register. All the 85 sperm samples were treated with sperm washing technique to reduce HCV in semen and the possible risk of transmission. We did not observe any preterm delivery or negative perinatal outcome. No mothers or babies are infected by HCV. This is the biggest prospective study conducted in a single center involving HCV discordant infertile couples in an ART program. Although sexual transmission of HCV is very low, in subfertile or infertile couples sperm washing should be used to treat HCV positive semen before ART. We suggest that it is not necessary to perform nested PCR to detect HCV RNA in the final swim-up. Since the presence of HCV in semen implies a possible risk of nosocomial contamination, safety regulations must be strictly applied in assisted reproduction laboratories. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.
Becker, Julie; Hernandez, Ambrosio; Dipietro, Michael; Coran, Arnold G
2005-07-01
Communicating bronchopulmonary foregut malformations (CBPFMs) are unusual congenital structures composed of a segment of lung tissue connected to the foregut. We present what we believe is the first reported case of identical twins concordant for CBPFM who are discordant for the VACTERL association. Their nonfunctional lung tissue was successfully removed and the fistulae were corrected, and they are expected to live normal life spans. We review the literature concerning these malformations and the proposed theories of their etiology. This case report of concordance in identical twins suggests that a possible genetic component to CBPFMs cannot be ruled out. The discordance for the VACTERL association implies that the etiology is most likely multifactorial.
Positive and purifying selection in mitochondrial genomes of a bird with mitonuclear discordance.
Morales, Hernán E; Pavlova, Alexandra; Joseph, Leo; Sunnucks, Paul
2015-06-01
Diversifying selection on metabolic pathways can reduce intraspecific gene flow and promote population divergence. An opportunity to explore this arises from mitonuclear discordance observed in an Australian bird Eopsaltria australis. Across >1500 km, nuclear differentiation is low and latitudinally structured by isolation by distance, whereas two highly divergent, parapatric mitochondrial lineages (>6.6% in ND2) show a discordant longitudinal geographic pattern and experience different climates. Vicariance, incomplete lineage sorting and sex-biased dispersal were shown earlier to be unlikely drivers of the mitonuclear discordance; instead, natural selection on a female-linked trait was the preferred hypothesis. Accordingly, here we tested for signals of positive, divergent selection on mitochondrial genes in E. australis. We used codon models and physicochemical profiles of amino acid replacements to analyse complete mitochondrial genomes of the two mitochondrial lineages in E. australis, its sister species Eopsaltria griseogularis, and outgroups. We found evidence of positive selection on at least five amino acids, encoded by genes of two oxidative phosphorylation pathway complexes NADH dehydrogenase (ND4 and ND4L) and cytochrome bc1 (cyt-b) against a background of widespread purifying selection on all mitochondrial genes. Three of these amino acid replacements were fixed in ND4 of the geographically most widespread E. australis lineage. The other two replacements were fixed in ND4L and cyt-b of the geographically more restricted E. australis lineage. We discuss whether this selection may reflect local environmental adaptation, a by-product of other selective processes, or genetic incompatibilities, and propose how these hypotheses can be tested in future. © 2015 John Wiley & Sons Ltd.
ERIC Educational Resources Information Center
Maurizi, Laura K.; Gershoff, Elizabeth T.; Aber, J. Lawrence
2012-01-01
The phenomenon of discordance between parents' and children's ratings of the child's mental health symptoms or of parenting behavior until recently has been treated as a problem of reliability. More recent work has sought to identify factors that may influence discordance, yet much remains to be learned about why informants' ratings of…
ERIC Educational Resources Information Center
Anastasiou, Dimitris; Michail, Domna
2013-01-01
The paper explores accordance or discordance between efficacy beliefs of adult students and their writing performance, using a mixed methods design. The participants are 33 students with learning disabilities (LD) and 35 low-achieving (LA) students, who were attending two Second-Chance Schools (SCSs), a specific type of adult education.…
Brown, Jennifer L; Sales, Jessica M; DiClemente, Ralph J; Salazar, Laura F; Vanable, Peter A; Carey, Michael P; Brown, Larry K; Romer, Daniel; Valois, Robert F; Stanton, Bonita
2012-08-01
This study examined correlates of the discordance between sexual behavior self-reports and Incident Sexually Transmitted Infections. African American adolescent females (N = 964) from four U.S. cities were recruited for an HIV/STI prevention trial. Self-reported sexual behaviors, demographics, and hypothesized psychosocial antecedents of sexual risk behavior were collected at baseline, 6-, 12-, and 18-month follow-up assessments. Urine specimens were collected and tested for three prevalent STIs (chlamydia, gonorrhea, trichomonas) at each assessment. Seventeen percent of participants with a laboratory-confirmed STI reported either lifetime abstinence or recent abstinence from vaginal sex (discordant self-report). Lower STI knowledge, belief that fewer peers were engaging in sex, and belief that more peers will wait until marriage to have sex were associated with discordant reports. Discordance between self-reported abstinence and incident STIs was marked among African American female adolescents. Lack of STI knowledge and sexual behavior peer norms may result in underreporting of sexual behaviors.
Sales, Jessica M.; DiClemente, Ralph J.; Salazar, Laura F.; Vanable, Peter A.; Carey, Michael P.; Brown, Larry K.; Romer, Daniel; Valois, Robert F.; Stanton, Bonita
2012-01-01
This study examined correlates of the discordance between sexual behavior self-reports and Incident Sexually Transmitted Infections. African American adolescent females (N = 964) from four U.S. cities were recruited for an HIV/STI prevention trial. Self-reported sexual behaviors, demographics, and hypothesized psychosocial antecedents of sexual risk behavior were collected at baseline, 6-, 12-, and 18-month follow-up assessments. Urine specimens were collected and tested for three prevalent STIs (chlamydia, gonorrhea, trichomonas) at each assessment. Seventeen percent of participants with a laboratory-confirmed STI reported either lifetime abstinence or recent abstinence from vaginal sex (discordant self-report). Lower STI knowledge, belief that fewer peers were engaging in sex, and belief that more peers will wait until marriage to have sex were associated with discordant reports. Discordance between self-reported abstinence and incident STIs was marked among African American female adolescents. Lack of STI knowledge and sexual behavior peer norms may result in underreporting of sexual behaviors. PMID:22323006
Adelson, Stewart L
2012-09-01
Children and adolescents who are growing up gay, lesbian, bisexual, gender nonconforming, or gender discordant experience unique developmental challenges. They are at risk for certain mental health problems, many of which are significantly correlated with stigma and prejudice. Mental health professionals have an important role to play in fostering healthy development in this population. Influences on sexual orientation, gender nonconformity, and gender discordance, and their developmental relationships to each other, are reviewed. Practice principles and related issues of cultural competence, research needs, and ethics are discussed. Copyright © 2012 American Academy of Child and Adolescent Psychiatry. Published by Elsevier Inc. All rights reserved.
Knowles, L Lacey; Huang, Huateng; Sukumaran, Jeet; Smith, Stephen A
2018-03-01
Discordant gene trees are commonly encountered when sequences from thousands of loci are applied to estimate phylogenetic relationships. Several processes contribute to this discord. Yet, we have no methods that jointly model different sources of conflict when estimating phylogenies. An alternative to analyzing entire genomes or all the sequenced loci is to identify a subset of loci for phylogenetic analysis. If we can identify data partitions that are most likely to reflect descent from a common ancestor (i.e., discordant loci that indeed reflect incomplete lineage sorting [ILS], as opposed to some other process, such as lateral gene transfer [LGT]), we can analyze this subset using powerful coalescent-based species-tree approaches. Test data sets were simulated where discord among loci could arise from ILS and LGT. Data sets where analyzed using the newly developed program CLASSIPHY (Huang et al., ) to assess whether our ability to distinguish the cause of discord among loci varied when ILS and LGT occurred in the recent versus deep past and whether the accuracy of these inferences were affected by the mutational process. We show that accuracy of probabilistic classification of individual loci by the cause of discord differed when ILS and LGT events occurred more recently compared with the distant past and that the signal-to-noise ratio arising from the mutational process contributes to difficulties in inferring LGT data partitions. We discuss our findings in terms of the promise and limitations of identifying subsets of loci for species-tree inference that will not violate the underlying coalescent model (i.e., data partitions in which ILS, and not LGT, contributes to discord). We also discuss the empirical implications of our work given the many recalcitrant nodes in the tree of life (e.g., origins of angiosperms, amniotes, or Neoaves), and recent arguments for concatenating loci. © 2018 Botanical Society of America.
Zarrinpar, Amir; Gupta, Shakti; Maurya, Mano R; Subramaniam, Shankar; Loomba, Rohit
2016-09-01
In the setting where two individuals are genetically similar, epigenetic mechanisms could account for discordance in the presence or absence of non-alcoholic fatty liver disease (NAFLD). This study investigated if serum microRNAs (miRs) could explain discordance in NAFLD. This is a cross-sectional analysis of a prospective cohort study of 40 (n=80) twin-pairs residing in Southern California. All participants underwent a standardised research visit, liver MRI using proton-density fat fraction to quantify fat content and miR profiling of their serum. Among the 40 twin-pairs, there were 6 concordant for NAFLD, 28 were concordant for non-NAFLD and 6 were discordant for NAFLD. The prevalence of NAFLD was 22.5% (18/80). Within the six discordant twins, a panel of 10 miRs differentiated the twin with NAFLD from the one without. Two of these miRs, miR-331-3p and miR-30c, were also among the 21 miRs that were different between NAFLD and non-NAFLD groups (for miR-331-3p: 7.644±0.091 vs 8.057±0.071, respectively, p=0.004; for miR-30c: 10.013±0.126 vs 10.418±0.086, respectively, p=0.008). Both miRs were highly heritable (35.9% and 10.7%, respectively) and highly correlated with each other (R=0.90, p=2.2×10(-16)) suggesting involvement in a common mechanistic pathway. An interactome analysis of these two miRs showed seven common target genes. Using a novel human twin-study design, we demonstrate that discordancy in liver fat content between the twins can be explained by miRs, and that they are heritable. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/
Bray, Timothy J P; Amies, Thomas; Vendhan, Kanimozhi; Humphries, Paul; Sen, Debajit; Ioannou, Yiannis; Hall-Craggs, Margaret A
2016-09-01
To determine the extent to which inflammation of the sacroiliac joints (SIJs) and apophyseal joints (AJs) changes concordantly after treatment in enthesitis-related arthritis (ERA). A retrospective study was performed with institutional review board approval. 31 young patients with ERA who had been scanned between March 2009 and November 2014 were included. All patients had post-contrast imaging of the SIJs and lumbar spine and short tau inversion-recovery (STIR) images of the SIJs. The severity of sacroiliitis was scored using a modification of an established technique, and inflammation of the AJs was evaluated using a recently described grading system. The changes in SIJ and AJ scores after treatment were classified as either concordant or discordant, and the proportion of scan pairs in these groups was recorded. In addition, the correlation between change in SIJ STIR score (Δnfla) and change in AJ score (ΔAJ) was assessed using Spearman's correlation coefficient. Of a total of 43 scan pairs, the changes in inflammation were concordant in 16 scan pairs and discordant in 27 scan pairs. There was no significant correlation between Δnfla and ΔAJ (R = 0.14, p = 0.37). Inflammatory changes in the SIJs and AJs are often discordant. This may be a reason why patients experience ongoing back pain despite apparent improvement in one or the other site. Inflammation may behave differently at different anatomical sites. The SIJs and AJs should both be imaged in patients with ERA with back pain.
Xu, Yuejuan; Li, Tingting; Pu, Tian; Cao, Ruixue; Long, Fei; Chen, Sun; Sun, Kun; Xu, Rang
2017-12-01
Congenital heart disease (CHD) is one of the most common birth defects. More than 200 susceptibility loci have been identified for CHDs, yet a large part of the genetic risk factors remain unexplained. Monozygotic (MZ) twins are thought to be completely genetically identical; however, discordant phenotypes have been found in MZ twins. Recent studies have demonstrated genetic differences between MZ twins. We aimed to test whether copy number variants (CNVs) and/or genetic mutation differences play a role in the etiology of CHDs by using single nucleotide polymorphism (SNP) genotyping arrays and whole exome sequencing of twin pairs discordant for CHDs. Our goal was to identify mutations present only in the affected twins, which could identify novel candidates for CHD susceptibility loci. We present a comprehensive analysis for the CNVs and genetic mutation results of the selected individuals but detected no consistent differences within the twin pairs. Our study confirms that chromosomal structure or genetic mutation differences do not seem to play a role in the MZ twins discordant for CHD.
Discordant transsexualism in male monozygotic twins: neuroanatomical and psychological differences.
Andreazza, Tahiana Signorini; Costa, Angelo Brandelli; Massuda, Raffael; Salvador, Jaqueline; Silveira, Esalba Maria; Piccon, Felipe; Carvalho, Renata; Fontanari, Anna Martha Vaitses; Koff, Walter; Belmonte-de-Abreu, Paulo; Lobato, Maria Inês Rodrigues
2014-02-01
One monozygotic male twin pair discordant for transsexualism is described. Both twins were interviewed and tested with the Wechsler Adult Intelligence Scale battery for cognitive functions and they underwent magnetic resonance imaging to measure the volumes of specific cerebral structures. Interviews with the twins and their mother indicated no unusual medical or life history events that could have had a causal role in the emergence of the disorder. Both cognitive function testing and neuroimaging detected differences between the twins that could be related to unexplained epigenetic effects and exogenous hormone usage.
Quantum Correlation Properties in Two Qubits One-axis Spin Squeezing Model
NASA Astrophysics Data System (ADS)
Guo-Hui, Yang
2017-02-01
Using the concurrence (C) and quantum discord (QD) criterions, the quantum correlation properties in two qubits one-axis spin squeezing model with an external magnetic field are investigated. It is found that one obvious difference in the limit case T → 0 (ground state) is the sudden disappearance phenomenon (SDP) occured in the behavior of C, while not in QD. In order to further explain the SDP, we obtain the analytic expressions of ground state C and QD which reveal that the SDP is not really "entanglement sudden disappeared", it is decayed to zero very quickly. Proper tuning the parameters μ(the spin squeezing interaction in x direction) and Ω(the external magnetic field in z direction) not only can obviously broaden the scope of ground state C exists but also can enhance the value of ground state QD. For the finite temperature case, one evident difference is that the sudden birth phenomenon (SBP) is appeared in the evolution of C, while not in QD, and decreasing the coupling parameters μ or Ω can obviously prolong the time interval before entanglement sudden birth. The value of C and QD are both enhanced by increasing the parameters μ or Ω in finite temperature case. In addition, through investigating the effects of temperature T on the quantum correlation properties with the variation of Ω and μ, one can find that the temperature scope of C and QD exists are broadened with increasing the parameters μ or Ω, and one can obtain the quantum correlation at higher temperature through changing these parameters.
NASA Astrophysics Data System (ADS)
Pandya, Palash; Misra, Avijit; Chakrabarty, Indranil
2016-11-01
We find a single parameter family of genuinely entangled three-qubit pure states, called the maximally Bell-inequality violating states (MBV), which exhibit maximum Bell-inequality violation by the reduced bipartite system for a fixed amount of genuine tripartite entanglement quantified by the so-called tangle measure. This in turn implies that there holds a complementary relation between the Bell-inequality violation by the reduced bipartite systems and the tangle present in the three-qubit states, not necessarily pure. The MBV states also exhibit maximum Bell-inequality violation by the reduced bipartite systems of the three-qubit pure states with a fixed amount of genuine tripartite correlation quantified by the generalized geometric measure, a genuine entanglement measure of multiparty pure states, and the discord monogamy score, a multipartite quantum correlation measure from information-theoretic paradigm. The aforementioned complementary relation has also been established for three-qubit pure states for the generalized geometric measure and the discord monogamy score, respectively. The complementarity between the Bell-inequality violation by the reduced bipartite systems and the genuine tripartite correlation suggests that the Bell-inequality violation in the reduced two-qubit system comes at the cost of the total tripartite correlation present in the entire system.
Roos, Leonie; van Dongen, Jenny; Bell, Christopher G; Burri, Andrea; Deloukas, Panos; Boomsma, Dorret I; Spector, Tim D; Bell, Jordana T
2016-01-01
A key focus in cancer research is the discovery of biomarkers that accurately diagnose early lesions in non-invasive tissues. Several studies have identified malignancy-associated DNA methylation changes in blood, yet no general cancer biomarker has been identified to date. Here, we explore the potential of blood DNA methylation as a biomarker of pan-cancer (cancer of multiple different origins) in 41 female cancer discordant monozygotic (MZ) twin-pairs sampled before or after diagnosis using the Illumina HumanMethylation450 BeadChip. We analysed epigenome-wide DNA methylation profiles in 41 cancer discordant MZ twin-pairs with affected individuals diagnosed with tumours at different single primary sites: the breast, cervix, colon, endometrium, thyroid gland, skin (melanoma), ovary, and pancreas. No significant global differences in whole blood DNA methylation profiles were observed. Epigenome-wide analyses identified one novel pan-cancer differentially methylated position at false discovery rate (FDR) threshold of 10 % (cg02444695, P = 1.8 × 10(-7)) in an intergenic region 70 kb upstream of the SASH1 tumour suppressor gene, and three suggestive signals in COL11A2, AXL, and LINC00340. Replication of the four top-ranked signals in an independent sample of nine cancer-discordant MZ twin-pairs showed a similar direction of association at COL11A2, AXL, and LINC00340, and significantly greater methylation discordance at AXL compared to 480 healthy concordant MZ twin-pairs. The effects at cg02444695 (near SASH1), COL11A2, and LINC00340 were the most promising in biomarker potential because the DNA methylation differences were found to pre-exist in samples obtained prior to diagnosis and were limited to a 5-year period before diagnosis. Gene expression follow-up at the top-ranked signals in 283 healthy individuals showed correlation between blood methylation and gene expression in lymphoblastoid cell lines at PRL, and in the skin tissue at AXL. A significant
Navigating Decisional Discord: The Pediatrician's Role When Child and Parents Disagree.
Sisk, Bryan A; DuBois, James; Kodish, Eric; Wolfe, Joanne; Feudtner, Chris
2017-06-01
From the time when children enter the preteen years onward, pediatric medical decision-making can entail a complex interaction between child, parents, and pediatrician. When the child and parents disagree regarding medical decisions, the pediatrician has the challenging task of guiding the family to a final decision. Unresolved discord can affect family cohesiveness, patient adherence, and patient self-management. In this article, we outline 3 models for the pediatrician's role in the setting of decisional discord: deference, advocative, and arbitrative. In the deference model, the pediatrician prioritizes parental decision-making authority. In the advocative model, the pediatrician advocates for the child's preference in decision-making so long as the child's decision is medically reasonable. In the arbitrative model, the pediatrician works to resolve the conflict in a balanced fashion. Although each model has advantages and disadvantages, the arbitrative model should serve as the initial model in nearly all settings. The arbitrative model is likely to reach the most beneficial decision in a manner that maintains family cohesiveness by respecting the authority of parents and the developing autonomy of children. We also highlight, however, occasions when the deference or advocative models may be more appropriate. Physicians should keep all 3 models available in their professional toolkit and develop the wisdom to deploy the right model for each particular clinical situation. Copyright © 2017 by the American Academy of Pediatrics.
Amies, Thomas; Vendhan, Kanimozhi; Humphries, Paul; Sen, Debajit; Ioannou, Yiannis; Hall-Craggs, Margaret A
2016-01-01
Objective: To determine the extent to which inflammation of the sacroiliac joints (SIJs) and apophyseal joints (AJs) changes concordantly after treatment in enthesitis-related arthritis (ERA). Methods: A retrospective study was performed with institutional review board approval. 31 young patients with ERA who had been scanned between March 2009 and November 2014 were included. All patients had post-contrast imaging of the SIJs and lumbar spine and short tau inversion-recovery (STIR) images of the SIJs. The severity of sacroiliitis was scored using a modification of an established technique, and inflammation of the AJs was evaluated using a recently described grading system. The changes in SIJ and AJ scores after treatment were classified as either concordant or discordant, and the proportion of scan pairs in these groups was recorded. In addition, the correlation between change in SIJ STIR score (Δnfla) and change in AJ score (ΔAJ) was assessed using Spearman's correlation coefficient. Results: Of a total of 43 scan pairs, the changes in inflammation were concordant in 16 scan pairs and discordant in 27 scan pairs. There was no significant correlation between Δnfla and ΔAJ (R = 0.14, p = 0.37). Conclusion: Inflammatory changes in the SIJs and AJs are often discordant. This may be a reason why patients experience ongoing back pain despite apparent improvement in one or the other site. Advances in knowledge: Inflammation may behave differently at different anatomical sites. The SIJs and AJs should both be imaged in patients with ERA with back pain. PMID:27376529
Burelli, Gabrielle; Berthelier, Chloé; Vanacker, Hélène; Descaillot, Léonard; Philippon-Jouve, Bénédicte; Fabre, Xavier; Kaaki, Mahmoud; Chakarian, Jean-Charles; Domine, Alexandre; Beuret, Pascal
2018-06-01
This study aimed to evaluate the impact of a visual aid on the discordance about prognosis between physicians and family members. The study was performed in a general intensive care department with two 6-bed units. In the unit A, family members could consult a visual aid depicting day by day the evolution of global, hemodynamic, respiratory, renal and neurological conditions of the patient on a 10-point scale. In the unit B, they only received oral medical information. On day 7 of the ICU stay, the physician and family members estimated the prognosis of the patient among four proposals (life threatened; steady state but may worsen; steady state, should heal; will heal). Then we compared the rate of discordance about prognosis between physicians and family members in the two units. Seventy-nine consecutive patients admitted in the intensive care department and still present at day 7, their family members and physicians, were enrolled. Patients in the two units were comparable in age, sex ratio, reason for admission, SAPS II at admission and SOFA score at day 7. In the unit A, physician-family members discordance about prognosis occurred for 12 out of 39 patients (31%) vs. 22 out of 40 patients (55%) in the unit B (P=0.04). In our study, adding a visual aid depicting the evolution of the condition of critically ill patients day by day to classic oral information allowed the family to have an estimate of the prognosis less discordant with the estimate of the physician. Copyright © 2018 Société française d'anesthésie et de réanimation (Sfar). Published by Elsevier Masson SAS. All rights reserved.
Zhao, Jing; Chen, Xiaotong; Zheng, Jing; Kong, Mei; Wang, Bo; Ding, Wei
2018-02-21
ROS1 immunohistochemistry (IHC) using D4D6 antibody is a useful tool for screening patients with non-small-cell lung cancer (NSCLC) who may be suitable for targeted therapy. Many studies and our data have identified cases that express the ROS1 protein strongly but are negative for ROS1 by fluorescence in-situ hybridisation (FISH). The present study investigated the driver mutation and clinicopathological characteristics of 26 discordant cases (ROS1 IHC-positive but FISH-negative) to find new clues for distinguishing real ROS1-rearranged cases. Tumours from 26 discordant cases were analysed for clinicopathological characteristics, mutations in EGFR, KRAS, ERBB2, BRAF and PIK3CA; fusions in ALK and RET; and amplifications in MET, ERBB2 and ROS1. ROS1-rearranged NSCLCs were significantly more likely to be found in younger patients and at an advanced stage; they showed cribriform features, extracellular mucus and psammoma bodies, whereas ROS1-discordant cases were found in older patients at a relatively early tumour-node-metastasis (TNM) stage and showed a lepidic growth pattern (all P < 0.001). Most ROS1-rearranged NSCLCs had no concurrent mutation, whereas 73% of discordant cases harboured genetic aberrations, including EGFR and ERBB2. Compared with general lung adenocarcinomas, ERBB-2 abnormality was disproportionately high in ROS1-discordant cases. Moreover, we optimised the scoring criteria for ROS1 IHC as 'H score > 150 and no concurrent mutations'; the specificity was then increased to 81.6%. Compared with ROS1-rearranged cases, ROS1-discordant patients showed distinct clinical and morphological features and often harboured another oncogenic driver alteration. The use of optimised screening criteria will increase the specificity of ROS1 antibody. © 2018 John Wiley & Sons Ltd.
Medical history of discordant twins and environmental etiologies of autism.
Willfors, C; Carlsson, T; Anderlid, B-M; Nordgren, A; Kostrzewa, E; Berggren, S; Ronald, A; Kuja-Halkola, R; Tammimies, K; Bölte, S
2017-01-31
The environmental contributions to autism spectrum disorder (ASD) and their informative content for diagnosing the condition are still largely unknown. The objective of this study was to investigate associations between early medical events and ASD, as well as autistic traits, in twins, to test the hypothesis of a cumulative environmental effect on ASD risk. A total of 80 monozygotic (MZ) twin pairs (including a rare sample of 13 twin pairs discordant for clinical ASD) and 46 dizygotic (DZ) twin pairs with varying autistic traits, were examined for intra-pair differences in early medical events (for example, obstetric and neonatal factors, first year infections). First, differences in early medical events were investigated using multisource medical records in pairs qualitatively discordant for ASD. The significant intra-pair differences identified were then tested in relation to autistic traits in the remaining sample of 100 pairs, applying generalized estimating equations analyses. Significant association of the intra-pair differences in the MZ pairs were found for the cumulative load of early medical events and clinical ASD (Z=-2.85, P=0.004) and autistic traits (β=78.18, P=0.002), as well as infant dysregulation (feeding, sleeping abnormalities, excessive crying and worriedness), when controlling for intelligence quotient and attention deficit hyperactivity disorder comorbidity. The cumulative load of early medical events in general, and infant dysregulation in particular, may index children at risk of ASD owing to non-shared environmental contributions. In clinical practice, these findings may facilitate screening and early detection of ASD.
Wang, Charmaine Tze May; Fong, Warren; Kwan, Yu Heng; Phang, Jie Kie; Lui, Nai Lee; Leung, Ying Ying; Thumboo, Julian; Cheung, Peter P
2018-06-19
To identify the factors associated with patient-physician discordance in patients with axial spondyloarthritis (axSpA) in an Asian population. A cross-sectional study was conducted in two tertiary referral centers in Singapore. Patients with axSpA who fulfilled Assessment in Ankylosing Spondylitis International Working Group 2009 criteria for axSpA were included in the study. Socio-demographics, clinical, laboratory and patient-reported outcomes data were collected during study visits from 2014 to 2015. We performed univariate and multivariate linear regression analyses to evaluate the factors associated with patient-physician discordance, which we defined as the difference between Patient Global Assessment and Physician Global Assessment. Included in the study were 298 axSpA patients: 82% male, 81% Chinese, median age 40 (20-78) years, median disease duration 9 (0.1-48) years. 80% were on non-steroidal anti-inflammatory drugs and 23% on biologics. In univariate analysis, current age (β: 0.18, ρ = 0.06), duration of disease (β: 0.34, ρ = 0.03), post-secondary education level (β: -10.82, ρ = 0.03), global pain score (β: 0.33, ρ < 0.01), Bath Ankylosing Spondylitis Functional Index (β: 2.80, ρ < 0.01), Ankylosing Spondylitis Disease Activity Score C-reactive protein (β: 4.63, ρ < 0.01) and current use of biologics (β: 10.97, ρ < 0.01) were associated with patient-physician discordance. In multivariate analysis, global pain score (β: 0.32, ρ < 0.01), post-secondary education level (β: -12.80, ρ = 0.01) and current biologics use (β: 16.21, ρ < 0.01) were associated with patient-physician discordance. Higher global pain score, lower educational level and current biologics use were associated with greater patient-physician discordance. These factors should be considered during shared decision making. © 2018 Asia Pacific League of Associations for Rheumatology and John Wiley & Sons Australia, Ltd.
Sexual risk factors for partner age discordance in adolescent girls and their male partners.
Morrison-Beedy, Dianne; Xia, Yinglin; Passmore, Denise
2013-12-01
To investigate differences in sexual risk factors between adolescent girls reporting similar-aged or older sex partners. Adolescent girls are at significant risk of heterosexual-acquired HIV infection and other long-term reproductive health issues. Sexual partner age discordance in teen girls has been correlated with STIs, lack of protection, multiple partners and earlier age of sexual transition. A descriptive study comparing girls currently involved with age-discordant partners to those with similar-aged partners. Two-sample t-test for continuous variables and chi-squared test or Fisher's exact test for categorical variables were used to compare groups. Baseline data from 738 sexually active, urban, adolescent girls aged 15-19 were analysed to determine which behaviours were more likely to occur in girls with older partners. Data were collected as part of a gender-specific HIV-prevention intervention in a randomised controlled trial (RCT) tailored to adolescent girls. Multiple reported sexual risk behaviours were found to significantly differ between the two groups at baseline. Overall, girls with older partners had more episodes of sexual instances (vaginal, anal and oral). Specific sexual risk behaviours were found to be statistically significant between the two groups. Girls with older partners started having sex at earlier ages, had more lifetime sexual partners, higher incidents of STIs and were reluctant to discuss using condoms with their partners. Girls with similar-aged partners were less willing to engage in risky sexual behaviours. Findings from this investigation support data from other studies. Relationships with older male partners place adolescent girls at increased risk of HIV/STIs and unintended pregnancy. Adolescent girls in age-discordant relationships are at risk of immediate and long-term sexual health morbidities. Identifying girls who are at increased risk by asking tailored questions will enable nurses to recommend appropriate diagnostics
Hagiwara, Nao; Penner, Louis A.; Gonzalez, Richard; Eggly, Susan; Dovidio, John F.; Gaertner, Samuel L.; West, Tessa; Albrecht, Terrance L.
2013-01-01
Physician racial bias and patient perceived discrimination have each been found to influence perceptions of and feelings about racially discordant medical interactions. However, to our knowledge, no studies have examined how they may simultaneously influence the dynamics of these interactions. This study examined how (a) non-Black primary care physicians’ explicit and implicit racial bias and (b) Black patients’ perceived past discrimination affected physician-patient talk time ratio (i.e., the ratio of physician to patient talk time) during medical interactions and the relationship between this ratio and patients’ subsequent adherence. We conducted a secondary analysis of self-report and video-recorded data from a prior study of clinical interactions between 112 low-income, Black patients and their 14 non-Black physicians at a primary care clinic in the Midwestern United States between June, 2006 and February, 2008. Overall, physicians talked more than patients; however, both physician bias and patient perceived past discrimination affected physician-patient talk time ratio. Non-Black physicians with higher levels of implicit, but not explicit, racial bias had larger physician-patient talk time ratios than did physicians with lower levels of implicit bias, indicating that physicians with more negative implicit racial attitudes talked more than physicians with less negative racial attitudes. Additionally, Black patients with higher levels of perceived discrimination had smaller physician-patient talk time ratios, indicating that patients with more negative racial attitudes talked more than patients with less negative racial attitudes. Finally, smaller physician-patient talk time ratios were associated with less patient subsequent adherence, indicating that patients who talked more during the racially discordant medical interactions were less likely to adhere subsequently. Theoretical and practical implications of these findings are discussed in the context of
Mitchell, Shanti R; Reiss, Allan L; Tatusko, Danielle H; Ikuta, Ichiro; Kazmerski, Dana B; Botti, Jo-Anna C; Burnette, Courtney P; Kates, Wendy R
2009-08-01
Investigating neuroanatomic differences in monozygotic twins who are discordant for autism can help unravel the relative contributions of genetics and environment to this pervasive developmental disorder. The authors used magnetic resonance imaging (MRI) to investigate several brain regions of interest in monozygotic twins who varied in degree of phenotypic discordance for narrowly defined autism. The subjects were 14 pairs of monozygotic twins between the ages of 5 and 14 years old and 14 singleton age- and gender-matched typically developing comparison subjects. The monozygotic twin group was a cohort of children with narrowly defined autistic deficits and their co-twins who presented with varying levels of autistic deficits. High-resolution MRIs were acquired and volumetric/area measurements obtained for the frontal lobe, amygdala, and hippocampus and subregions of the prefrontal cortex, corpus callosum, and cerebellar vermis. No neurovolumetric/area differences were found between twin pairs. Relative to typically developing comparison subjects, dorsolateral prefrontal cortex volumes and anterior areas of the corpus callosum were significantly altered in autistic twins, and volumes of the posterior vermis were altered in both autistic twins and co-twins. Intraclass correlation analysis of brain volumes between children with autism and their co-twins indicated that the degree of within-pair neuroanatomic concordance varied with brain region. In the group of subjects with narrowly defined autism only, dorsolateral prefrontal cortex, amygdala, and posterior vermis volumes were significantly associated with the severity of autism based on scores from the Autism Diagnostic Observation Schedule-Generic. These findings support previous research demonstrating alterations in the prefrontal cortex, corpus callosum, and posterior vermis in children with autism and further suggest that alterations are associated with the severity of the autism phenotype. Continued research
ERIC Educational Resources Information Center
Cummings, E. Mark; Schermerhorn, Alice C.; Davies, Patrick T.; Goeke-Morey, Marcie C.; Cummings, Jennifer S.
2006-01-01
Advancing the process-oriented study of links between interparental discord and child adjustment, 2 multimethod prospective tests of emotional security as an explanatory mechanism are reported. On the basis of community samples, with waves spaced 2 years apart, Study 1 (113 boys and 113 girls, ages 9-18) identified emotional security as a mediator…
Steady-state entanglement activation in optomechanical cavities
NASA Astrophysics Data System (ADS)
Farace, Alessandro; Ciccarello, Francesco; Fazio, Rosario; Giovannetti, Vittorio
2014-02-01
Quantum discord, and related indicators, are raising a relentless interest as a novel paradigm of nonclassical correlations beyond entanglement. Here, we discover a discord-activated mechanism yielding steady-state entanglement production in a realistic continuous-variable setup. This comprises two coupled optomechanical cavities, where the optical modes (OMs) communicate through a fiber. We first use a simplified model to highlight the creation of steady-state discord between the OMs. We show next that such discord improves the level of stationary optomechanical entanglement attainable in the system, making it more robust against temperature and thermal noise.
Novel epigenetic changes unveiled by monozygotic twins discordant for smoking habits.
Allione, Alessandra; Marcon, Francesca; Fiorito, Giovanni; Guarrera, Simonetta; Siniscalchi, Ester; Zijno, Andrea; Crebelli, Riccardo; Matullo, Giuseppe
2015-01-01
Exposure to cigarette smoking affects the epigenome and could increase the risk of developing diseases such as cancer and cardiovascular disorders. Changes in DNA methylation associated with smoking may help to identify molecular pathways that contribute to disease etiology. Previous studies are not completely concordant in the identification of differentially methylated regions in the DNA of smokers. We performed an epigenome-wide DNA methylation study in a group of monozygotic (MZ) twins discordant for smoking habits to determine the effect of smoking on DNA methylation. As MZ twins are considered genetically identical, this model allowed us to identify smoking-related DNA methylation changes independent from genetic components. We investigated the whole blood genome-wide DNA methylation profiles in 20 MZ twin pairs discordant for smoking habits by using the Illumina HumanMethylation450 BeadChip. We identified 22 CpG sites that were differentially methylated between smoker and non-smoker MZ twins by intra-pair analysis. We confirmed eight loci already described by other groups, located in AHRR, F2RL3, MYOG1 genes, at 2q37.1 and 6p21.33 regions, and also identified several new loci. Moreover, pathway analysis showed an enrichment of genes involved in GTPase regulatory activity. Our study confirmed the evidence of smoking-related DNA methylation changes, emphasizing that well-designed MZ twin models can aid the discovery of novel DNA methylation signals, even in a limited sample population.
DNA damage response in monozygotic twins discordant for smoking habits.
Marcon, Francesca; Carotti, Daniela; Andreoli, Cristina; Siniscalchi, Ester; Leopardi, Paola; Caiola, Stefania; Biffoni, Mauro; Zijno, Andrea; Medda, Emanuela; Nisticò, Lorenza; Rossi, Sabrina; Crebelli, Riccardo
2013-03-01
Previous studies in twins indicate that non-shared environment, beyond genetic factors, contributes substantially to individual variation in mutagen sensitivity; however, the role of specific causative factors (e.g. tobacco smoke, diet) was not elucidated. In this investigation, a population of 22 couples of monozygotic twins with discordant smoking habits was selected with the aim of evaluating the influence of tobacco smoke on individual response to DNA damage. The study design virtually eliminated the contribution of genetic heterogeneity to the intra-pair variation in DNA damage response, and thus any difference in the end-points investigated could directly be attributed to the non-shared environment experienced by co-twins, which included as main factor cigarette smoke exposure. Peripheral lymphocytes of study subjects were challenged ex vivo with γ-rays, and the induction, processing, fixation of DNA damage evaluated through multiple approaches. Folate status of study subjects was considered significant covariate since it is affected by smoking habits and can influence radiosensitivity. Similar responses were elicited by γ-rays in co-twins for all the end-points analysed, despite their discordant smoking habits. Folate status did not modify DNA damage response, even though a combined effect of smoking habits, low-plasma folic acid level, and ionising radiation was observed on apoptosis. A possible modulation of DNA damage response by duration and intensity of tobacco smoke exposure was suggested by Comet assay and micronucleus data, but the effect was quantitatively limited. Overall, the results obtained indicate that differences in smoking habits do not contribute to a large extent to inter-individual variability in the response to radiation-induced DNA damage observed in healthy human populations.
van ’t Ent, D.; Lehn, H.; Derks, E.M.; Hudziak, J.J.; Van Strien, N.M.; Veltman, D.J.; De Geus, E.J.C.; Todd, R.D.; Boomsma, D.I.
2007-01-01
Several structural brain abnormalities have been reported in patients with Attention Deficit Hyperactivity Disorder (ADHD). However, the aetiology of these brain changes is still unclear. To investigate genetic and environmental influences on ADHD related neurobiological changes we performed Voxel Based Morphometry on MRI scans from monozygotic (MZ) twins selected from a large longitudinal population database to be highly concordant or highly discordant for ratings on the Child Behavior Checklist Attention Problem scale (CBCL-AP). Children scoring low on the CBCL-AP are at low risk for ADHD, whereas children scoring high on this scale are at high risk for ADHD. Brain differences between concordant high risk twin pairs and concordant low risk twin pairs likely reflect the genetic risk for ADHD; brain differences between the low risk and high risk twins from discordant MZ twin pairs reflect the environmental risk for ADHD. A major difference between comparisons of high and low risk twins from concordant pairs and high/low twins from discordant pairs was found for the prefrontal lobes. The concordant high risk pairs showed volume loss in orbitofrontal subdivisions. High risk members from the discordant twin pairs exhibited volume reduction in the right inferior dorsolateral prefontal cortex. In addition, the posterior corpus callosum was compromised in concordant high risk pairs, only. Our findings indicate that inattention and hyperactivity symptoms are associated with anatomical abnormalities of a distributed action-attentional network. Different brain areas of this network appear to be affected in inattention/hyperactivity caused by genetic (i.e., high concordant MZ pairs) versus environmental (i.e., high-low discordant MZ pairs) risk factors. These results provide clues that further our understanding of brain alterations in ADHD. PMID:17346990
A Discordant Monozygotic Twin Design Shows Blunted Cortisol Reactivity Among Bullied Children
Ouellet-Morin, Isabelle; Danese, Andrea; Bowes, Lucy; Shakoor, Sania; Ambler, Antony; Pariante, Carmine M.; Papadopoulos, Andrew S.; Caspi, Avshalom; Moffitt, Terrie E.; Arseneault, Louise
2013-01-01
Objective Childhood adverse experiences are known to engender persistent changes in stress-related systems and brain structures involved in mood, cognition, and behavior in animal models. Uncertainty remains about the causal effect of early stressful experiences on physiological response to stress in human beings, as the impact of these experiences has rarely been investigated while controlling for both genetic and shared environmental influences. Method We tested whether bullying victimization, a repeated adverse experience in childhood, influences cortisol responses to a psychosocial stress test (PST) using a discordant monozygotic (MZ) twin design. Thirty pairs (43.3% males) of 12-year-old MZ twins discordant for bullying victimization were identified in the Environmental Risk (E-Risk) Longitudinal Twin Study, a nationally representative 1994–1995 cohort of families with twins. Results Bullied and nonbullied MZ twins showed distinct patterns of cortisol secretion after the PST. Specifically, bullied twins exhibited a blunted cortisol response compared with their nonbullied MZ co-twins, who showed the expected increase. This difference in cortisol response to stress could not be attributed to children's genetic makeup, their familial environments, pre-existing and concomitant individual factors, or the perception of stress and emotional response to the PST. Conclusion Results from this natural experiment provide support for a causal effect of adverse childhood experiences on the neuroendocrine response to stress. PMID:21621141
Navigating Decisional Discord: The Pediatrician’s Role When Child and Parents Disagree
DuBois, James; Kodish, Eric; Wolfe, Joanne; Feudtner, Chris
2017-01-01
From the time when children enter the preteen years onward, pediatric medical decision-making can entail a complex interaction between child, parents, and pediatrician. When the child and parents disagree regarding medical decisions, the pediatrician has the challenging task of guiding the family to a final decision. Unresolved discord can affect family cohesiveness, patient adherence, and patient self-management. In this article, we outline 3 models for the pediatrician’s role in the setting of decisional discord: deference, advocative, and arbitrative. In the deference model, the pediatrician prioritizes parental decision-making authority. In the advocative model, the pediatrician advocates for the child’s preference in decision-making so long as the child’s decision is medically reasonable. In the arbitrative model, the pediatrician works to resolve the conflict in a balanced fashion. Although each model has advantages and disadvantages, the arbitrative model should serve as the initial model in nearly all settings. The arbitrative model is likely to reach the most beneficial decision in a manner that maintains family cohesiveness by respecting the authority of parents and the developing autonomy of children. We also highlight, however, occasions when the deference or advocative models may be more appropriate. Physicians should keep all 3 models available in their professional toolkit and develop the wisdom to deploy the right model for each particular clinical situation. PMID:28562285
Jain, Vivek; Petersen, Maya L.; Liegler, Teri; Byonanebye, Dathan M.; Kwarisiima, Dalsone; Chamie, Gabriel; Sang, Norton; Black, Doug; Clark, Tamara D.; Ladai, Andras; Plenty, Albert; Kabami, Jane; Ssemmondo, Emmanuel; Bukusi, Elizabeth A.; Cohen, Craig R.; Charlebois, Edwin D.; Kamya, Moses R.; Havlir, Diane V.
2017-01-01
Background As Sub-Saharan Africa transitions to a new era of universal ART, up-to-date assessments of HIV RNA (viral load, VL) suppression at a population level are needed to understand demographic and geographic sources of ongoing viremia and to inform interventions to optimize ART delivery. We sought to measure population viral load (VL) metrics to assess current viral suppression levels and characterize demographic groups and geographic locations with high-level detectable viremia in East Africa. Methods In the SEARCH HIV test-and-treat study (NCT01864683), we conducted baseline HIV testing (89% uptake) and HIV RNA assessments in 32 rural communities in 2013–2014 in Uganda and Kenya (N=303,461). We measured VL in 8,828 HIV+ adults, and defined viral suppression as VL<500 copies/mL. To assess geographic sources of transmission risk, we determined the proportion of all adults (both HIV-positive and HIV-negative) with detectable VL (termed ‘local prevalence of viremia’). Transmission risk ‘hotspots’ were defined as geopolitical subunits within communities with >5.0% local prevalence of viremia. We also assessed sero-discordant couples, measuring the proportion in which the HIV+ partner had detectable viremia. Findings Viral suppression was 82% (3,427/4,202) among adults on ART, and 51% (4,490/8,828) among all HIV+ adults. Regional viral suppression among HIV+ adults was 48% (West Uganda), 45% (East Uganda) and 53% (Western Kenya). Transmission risk ‘hotspots’ included 1/21 W.Uganda, 0/18 E.Uganda, and 16/26 Kenya geopolitical subunits. In Uganda, sero-discordancy was 3.1% (492 discordant/16,023 total couples). In 58% of discordant couples, the HIV+ partner was viremic (14% had VL>100,000). In Kenya, sero-discordancy was 10.0% (859/8,616 total couples). In 53%, the HIV+ partner was viremic (15% with VL>100,000). Interpretation Prior to the 2013–2014 start of the SEARCH trial, 51% of East African HIV+ adults had viral suppression, reflecting ART scale
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ackermann, R.F.; Lear, J.L.
We have developed an autoradiographic method for estimating the oxidative and glycolytic components of local CMRglc (LCMRglc), using sequentially administered ({sup 18}F)fluorodeoxyglucose (FDG) and ({sup 14}C)-6-glucose (GLC). FDG-6-phosphate accumulation is proportional to the rate of glucose phosphorylation, which occurs before the divergence of glycolytic (GMg) and oxidative (GMo) glucose metabolism and is therefore related to total cerebral glucose metabolism GMt: GMg + GMo = GMt. With oxidative metabolism, the {sup 14}C label of GLC is temporarily retained in Krebs cycle-related substrate pools. We hypothesize that with glycolytic metabolism, however, a significant fraction of the {sup 14}C label is lost frommore » the brain via lactate production and efflux from the brain. Thus, cerebral GLC metabolite concentration may be more closely related to GMo than to GMt. If true, the glycolytic metabolic rate will be related to the difference between FDG- and GLC-derived LCMRglc. Thus far, we have studied normal awake rats, rats with limbic activation induced by kainic acid (KA), and rats visually stimulated with 16-Hz flashes. In KA-treated rats, significant discordance between FDG and GLC accumulation, which we attribute to glycolysis, occurred only in activated limbic structures. In visually stimulated rats, significant discordance occurred only in the optic tectum.« less
Makowski, Marcus R; Jansen, Christian H P; Ebersberger, Ullrich; Schaeffter, Tobias; Razavi, Reza; Mangino, Massimo; Spector, Tim D; Botnar, Rene M; Greil, Gerald F
2017-11-01
The aim of this study was to investigate the impact of BMI on late gadolinium enhancement (LGE) of the coronary artery wall in identical monozygous twins discordant for BMI. Coronary LGE represents a useful parameter for the detection and quantification of atherosclerotic coronary vessel wall disease. Thirteen monozygote female twin pairs (n = 26) with significantly different BMIs (>1.6 kg/m2) were recruited out of >10,000 twin pairs (TwinsUK Registry). A coronary 3D-T2prep-TFE MR angiogram and 3D-IR-TFE vessel wall scan were performed prior to and following the administration of 0.2 mmol/kg of Gd-DTPA on a 1.5 T MR scanner. The number of enhancing coronary segments and contrast to noise ratios (CNRs) of the coronary wall were quantified. An increase in BMI was associated with an increased number of enhancing coronary segments (5.3 ± 1.5 vs. 3.5 ± 1.6, p < 0.0001) and increased coronary wall enhancement (6.1 ± 1.1 vs. 4.8 ± 0.9, p = 0.0027) compared to matched twins with lower BMI. This study in monozygous twins indicates that acquired factors predisposing to obesity, including lifestyle and environmental factors, result in increased LGE of the coronary arteries, potentially reflecting an increase in coronary atherosclerosis in this female study population. • BMI-discordant twins allow the investigation of the influence of lifestyle factors independent from genetic confounders. • Only thirteen obesity-discordant twins were identified underlining the strong genetic component of BMI. • In female twins, a BMI increase is associated with increased coronary late gadolinium enhancement. • Increased late gadolinium enhancement in the coronary vessel wall potentially reflects increased atherosclerosis.
Adaptation in locomotor stability, cognition, and metabolic cost during sensory discordance.
Peters, Brian T; Brady, Rachel A; Batson, Crystal D; Guined, Jamie R; Ploutz-Snyder, Robert J; Mulavara, Ajitkumar P; Bloomberg, Jacob J
2013-06-01
Locomotor instability may affect planetary extravehicular activities during the initial adaptation to the new gravitational environment. The goal of this study was to quantify the locomotor, cognitive, and metabolic effects of exposure to a discordant sensory environment. A treadmill mounted on a 6-degree-of-freedom motion base was used to present 15 healthy subjects with a destabilizing support surface while they walked. Dependent measures of locomotor stability, cognitive load, and metabolic cost were stride frequency (SF), reaction time (RT), and the volume of oxygen consumed (Vo2), respectively. Subjects completed an 8-min baseline walk followed by 20 min of walking with a continuous, sinusoidal, laterally oscillating support-surface perturbation. Data for minutes 1, 7, 13, and 20 of the support-surface perturbation period were compared with the baseline. SF, RT, and Vo2 were significantly greater during support-surface motion than during the baseline walking condition and showed a trend toward recovery to baseline levels during the perturbation period. Results demonstrated that adaptation to walking in a discordant sensory environment has quantifiable and significant costs in SF, RT, and Vo2 as shown by mean increases of 9%, 20%, and 4%, respectively, collected during the first minute of exposure. By the fourth minute of exposure, mean Vo2 consumption had increased to 20% over its baseline. We believe that preflight sensorimotor adaptation training paradigms will impart gains in stability and the ability to multitask, and might increase productive mission time by extending work time in extravehicular activity suits where metabolic expenditure is a limiting factor.
Syphilis treatment response among HIV-discordant couples in Zambia and Rwanda.
Dionne-Odom, Jodie; Karita, Etienne; Kilembe, William; Henderson, Faith; Vwalika, Bellington; Bayingana, Roger; Li, Zhigang; Mulenga, Joseph; Chomba, Elwyn; Del Rio, Carlos; Khu, Naw Htee; Tichacek, Amanda; Allen, Susan
2013-06-01
Syphilis continues to be a common sexually transmitted infection, despite the availability of inexpensive and effective treatment. Infection in human immunodeficiency virus (HIV)-discordant couples is important because syphilis increases the risk of HIV acquisition. Current US treatment guidelines recommend 1 dose of benzathine penicillin for early syphilis, irrespective of HIV status, but data from coinfected patients are limited. Retrospective analysis of 1321 individuals in 2 African HIV-discordant couple cohorts was performed. Cox proportional hazards analysis and multivariable modeling were used to assess predictors of serologic response to treatment at 180 days and 400 days. Modeling was performed for all episodes of positive rapid plasma reagin (RPR) test results and on a subset with higher RPR titers (≥1:4). A total of 1810 episodes of syphilis among 1321 individuals were treated with penicillin between 2002 and 2008. Although a positive RPR was more common in the HIV-infected partners, HIV infection did not impact the likelihood of serologic response to therapy (odds ratio [OR], 1.001; P = .995). By 400 days, 67% had responded to therapy, 27% were serofast, and 6.5% had documented reinfection. Prevalent infections were more likely to remain serofast than incident infections (33% vs 20% at 400 days). In 2 HIV-serodiscordant couple cohorts in Africa, incident syphilis had a very good likelihood of response to penicillin therapy, irrespective of HIV infection. This supports current Centers for Disease Control and Prevention treatment guidelines. A high proportion of prevalent RPR-positive infections remain serofast despite treatment.
Syphilis Treatment Response Among HIV-Discordant Couples in Zambia and Rwanda
Dionne-Odom, Jodie; Karita, Etienne; Kilembe, William; Henderson, Faith; Vwalika, Bellington; Bayingana, Roger; Li, Zhigang; Mulenga, Joseph; Chomba, Elwyn; del Rio, Carlos; Khu, Naw Htee; Tichacek, Amanda; Allen, Susan
2013-01-01
Background. Syphilis continues to be a common sexually transmitted infection, despite the availability of inexpensive and effective treatment. Infection in human immunodeficiency virus (HIV)–discordant couples is important because syphilis increases the risk of HIV acquisition. Current US treatment guidelines recommend 1 dose of benzathine penicillin for early syphilis, irrespective of HIV status, but data from coinfected patients are limited. Methods. Retrospective analysis of 1321 individuals in 2 African HIV-discordant couple cohorts was performed. Cox proportional hazards analysis and multivariable modeling were used to assess predictors of serologic response to treatment at 180 days and 400 days. Modeling was performed for all episodes of positive rapid plasma reagin (RPR) test results and on a subset with higher RPR titers (≥1:4). Results. A total of 1810 episodes of syphilis among 1321 individuals were treated with penicillin between 2002 and 2008. Although a positive RPR was more common in the HIV-infected partners, HIV infection did not impact the likelihood of serologic response to therapy (odds ratio [OR], 1.001; P = .995). By 400 days, 67% had responded to therapy, 27% were serofast, and 6.5% had documented reinfection. Prevalent infections were more likely to remain serofast than incident infections (33% vs 20% at 400 days). Conclusions. In 2 HIV-serodiscordant couple cohorts in Africa, incident syphilis had a very good likelihood of response to penicillin therapy, irrespective of HIV infection. This supports current Centers for Disease Control and Prevention treatment guidelines. A high proportion of prevalent RPR-positive infections remain serofast despite treatment. PMID:23487377
ERIC Educational Resources Information Center
Cookston, Jeffrey T.; Harrist, Amanda W.; Ainslie, Ricardo C.
2003-01-01
Indices of marital discord and mother-child affective processes were used to predict levels of negativity children displayed with unfamiliar peers. Thirty-nine mothers and their 5-year-olds were observed with 5-7 other mother-child dyads during a 30-minute free play session. Mother and child negativity were coded and two types of marital discord…
Discordant hepatic uptake between Tc-99m sulfur colloid and Tc-99m DISIDA in hypervitaminosis A
DOE Office of Scientific and Technical Information (OSTI.GOV)
Vincent, L.M.; McCartney, W.H.; Mauro, M.A.
1984-02-01
Scintigraphic findings in a patient with biopsy-proven hypervitaminosis A included markedly impaired hepatic uptake of Tc-99m sulfur colloid but essentially normal uptake of Tc-99m DISIDA. This case presents a potential cause for image discordance with these two agents.
Riehman, Kara S; Wechsberg, Wendee M; Francis, Shelley A; Moore, Melvin; Morgan-Lopez, Antonio
2006-11-01
The objectives of this study were to examine the association between individual and partnership characteristics with condom use, sexual concurrency, and discordance in monogamy perceptions among out-of-treatment, young adult, drug-involved couples to gain a better understanding of how discordance in monogamy beliefs may influence HIV/sexually transmitted infection risk. Data were collected from 94 predominantly black heavy alcohol and/or drug users (AOD) and their steady partners recruited through street outreach in Durham, North Carolina, and a methadone clinic in Raleigh, North Carolina. One third was wrong about partners' monogamy intentions. Greater lifetime number of substances, longer relationship duration, and at least weekly relationship conflict were associated with inconsistent condom use, and discordant monogamy beliefs were associated with consistent condom use. Many individuals misperceive their partners' monogamy intentions, although this misperception may be reflective of greater HIV/sexually transmitted infection protection. Interventions for couples should focus on strategies appropriate for committed long-term relationships, including increasing awareness of partner risk behavior, negotiating safety, and conflict resolution skills.
Lee, Yong Joo; Kim, Jung Eun; Choi, Youn Seon; Hwang, In Cheol; Hwang, Sun Wook; Kim, Young Sung; Kim, Hyo Min; Ahn, Hong Yup; Kim, So Jin
2016-07-01
Research studies on quality of life (QOL) discordance between cancer patients and family caregivers are limited, and the results are inconsistent. The objective of this study was to examine QOL discordance between patients and family caregivers in a hospice setting and to identify factors associated with the discordance. We enrolled 178 patient-family caregiver pairs from six tertiary hospital hospice palliative care units in South Korea in this cross-sectional study. To establish groupings based on patient and family caregiver QOL levels, we measured the QOL of patient and family caregiver pairs using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 15 for Palliative Care and the Caregiver QOL Index-Cancer, respectively. Pairs were categorized into the following three groups: both good QOL pairs, only poor patient QOL, and only poor family caregiver QOL. Factors associated with only poor patient or only poor family caregiver QOL were compared to both good QOL pairs. A stepwise multivariate regression model was used to identify relevant factors. The QOL of family caregivers did not correlate significantly (P = 0.227) with QOL in terminally ill cancer patients. As well, poor emotional function in patients was the only significant factor associated with the only poor patient QOL group [adjusted odds ratio (aOR), 4.1; 95 % confidence interval (CI), 1.5-11.5]. However, emotionally distressed family caregivers (aOR, 10.2; 95 % CI, 2.8-37.5), family caregivers who professed a religion (aOR, 4.1; 95 % CI, 1.5-11.3), and family caregivers with low social support (aOR, 3.9; 95 % CI, 1.5-10.6) were independent predictors for the only poor family caregiver QOL group. Assessing the respective emotional status of both the patient and family caregiver is needed in hospice care to reduce the gap in QOL between the two groups. Further, more attention should be paid to the lack of social support for family caregivers.
Planck data versus large scale structure: Methods to quantify discordance
NASA Astrophysics Data System (ADS)
Charnock, Tom; Battye, Richard A.; Moss, Adam
2017-06-01
Discordance in the Λ cold dark matter cosmological model can be seen by comparing parameters constrained by cosmic microwave background (CMB) measurements to those inferred by probes of large scale structure. Recent improvements in observations, including final data releases from both Planck and SDSS-III BOSS, as well as improved astrophysical uncertainty analysis of CFHTLenS, allows for an update in the quantification of any tension between large and small scales. This paper is intended, primarily, as a discussion on the quantifications of discordance when comparing the parameter constraints of a model when given two different data sets. We consider Kullback-Leibler divergence, comparison of Bayesian evidences and other statistics which are sensitive to the mean, variance and shape of the distributions. However, as a byproduct, we present an update to the similar analysis in [R. A. Battye, T. Charnock, and A. Moss, Phys. Rev. D 91, 103508 (2015), 10.1103/PhysRevD.91.103508], where we find that, considering new data and treatment of priors, the constraints from the CMB and from a combination of large scale structure (LSS) probes are in greater agreement and any tension only persists to a minor degree. In particular, we find the parameter constraints from the combination of LSS probes which are most discrepant with the Planck 2015 +Pol +BAO parameter distributions can be quantified at a ˜2.55 σ tension using the method introduced in [R. A. Battye, T. Charnock, and A. Moss, Phys. Rev. D 91, 103508 (2015), 10.1103/PhysRevD.91.103508]. If instead we use the distributions constrained by the combination of LSS probes which are in greatest agreement with those from Planck 2015 +Pol +BAO this tension is only 0.76 σ .
Postoperative Surgical Site Infections: Understanding the Discordance Between Surveillance Systems.
Ali-Mucheru, Mariam N; Seville, Maria T; Miller, Vickie; Sampathkumar, Priya; Etzioni, David A
2018-04-18
To characterize agreement in the ascertainment of surgical site infections (SSIs) between the National Surgical Quality Improvement Program (NSQIP), National Healthcare Safety Network (NHSN), and administrative data. The NSQIP, NHSN, and administrative data are the primary systems used to monitor and report SSIs for the purpose of quality control and benchmarking of hospitals and surgeons. These systems have different methods for identifying SSIs. We queried the NHSN, NSQIP, and administrative data systems for patients who had an operation at 1 of 4 hospitals within a single health system between January 2013 and September 2015. The detection of an SSI during a postoperative hospitalization was the outcome of analysis. Any SSI detected by one (or more) of these systems was analyzed by 2 reviewers to determine the presence of discrete elements of documentation constituting evidence of SSI. Concordance between the 3 systems (NHSN, NSQIP, and administrative data) was analyzed using Cohen's kappa. After application of appropriate exclusion criteria, a cohort of 9447 inpatient operations was analyzed. In total, 130 SSIs were detected by 1 or more of the 3 systems, with reported SSI rates of 0.5% (NHSN), 0.7% (administrative data), and 1.0% (NSQIP). Of these 130 SSIs, only 17 SSIs were reported by all 3 systems. The concordance between these 3 systems was moderate (kappa values NSQIP-NHSN = 0.50 [0.40-0.60], administrative-NHSN = 0.36 [0.24-0.47], and administrative-NSQIP = 0.47 [0.38-0.57]). Chart review found that reasons for discordance were related to issues of different criteria as well as inaccuracies. There is significant discordance in the determination of SSIs reported by the NHSN, NSQIP, and administrative data. The differences and limitations of each of these systems have to be recognized, especially when using these data for quality reports and pay for performance.
Mitochondrial DNA Copy Number in Sleep Duration Discordant Monozygotic Twins.
Wrede, Joanna E; Mengel-From, Jonas; Buchwald, Dedra; Vitiello, Michael V; Bamshad, Michael; Noonan, Carolyn; Christiansen, Lene; Christensen, Kaare; Watson, Nathaniel F
2015-10-01
Mitochondrial DNA (mtDNA) copy number is an important component of mitochondrial function and varies with age, disease, and environmental factors. We aimed to determine whether mtDNA copy number varies with habitual differences in sleep duration within pairs of monozygotic twins. Academic clinical research center. 15 sleep duration discordant monozygotic twin pairs (30 twins, 80% female; mean age 42.1 years [SD 15.0]). Sleep duration was phenotyped with wrist actigraphy. Each twin pair included a "normal" (7-9 h/24) and "short" (< 7 h/24) sleeping twin. Fasting peripheral blood leukocyte DNA was assessed for mtDNA copy number via the n-fold difference between qPCR measured mtDNA and nuclear DNA creating an mtDNA measure without absolute units. We used generalized estimating equation linear regression models accounting for the correlated data structure to assess within-pair effects of sleep duration on mtDNA copy number. Mean within-pair sleep duration difference per 24 hours was 94.3 minutes (SD 62.6 min). We found reduced sleep duration (β = 0.06; 95% CI 0.004, 0.12; P < 0.05) and sleep efficiency (β = 0.51; 95% CI 0.06, 0.95; P < 0.05) were significantly associated with reduced mtDNA copy number within twin pairs. Thus every 1-minute decrease in actigraphy-defined sleep duration was associated with a decrease in mtDNA copy number of 0.06. Likewise, a 1% decrease in actigraphy-defined sleep efficiency was associated with a decrease in mtDNA copy number of 0.51. Reduced sleep duration and sleep efficiency were associated with reduced mitochondrial DNA copy number in sleep duration discordant monozygotic twins offering a potential mechanism whereby short sleep impairs health and longevity through mitochondrial stress. © 2015 Associated Professional Sleep Societies, LLC.
NASA Technical Reports Server (NTRS)
Brady, Rachel A.; Batson, Crystal D.; Peters, Brian T.; Mulavara, Ajitkumar P.; Bloomberg, Jacob J.
2010-01-01
We designed a gait training study that presented combinations of visual flow and support surface manipulations to investigate the response of healthy adults to novel discordant sensorimotor conditions. We aimed to determine whether a relationship existed between subjects visual dependence and their scores on a collective measure of anxiety, cognition, and postural stability in a new discordant environment presented at the conclusion of training (Transfer Test). A treadmill was mounted to a motion base platform positioned 2 m behind a large visual screen. Training consisted of three walking sessions, each within a week of the previous visit, that presented four 5-minute exposures to various combinations of support surface and visual scene manipulations, all lateral sinusoids. The conditions were scene translation only, support surface translation only, simultaneous scene and support surface translations in-phase, and simultaneous scene and support surface translations 180 out-of-phase. During the Transfer Test, the trained participants received a 2-minute novel exposure. A visual sinusoidal roll perturbation, with twice the original flow rate, was superimposed on a sinusoidal support surface roll perturbation that was 90 out of phase with the scene. A high correlation existed between normalized torso translation, measured in the scene-only condition at the first visit, and a combined measure of normalized heart rate, stride frequency, and reaction time at the transfer test. Results suggest that visually dependent participants experience decreased postural stability, increased anxiety, and increased reaction times compared to their less visually dependent counterparts when negotiating novel discordant conditions.
Altet-Gómez, N; De Souza-Galvao, M; Latorre, I; Milà, C; Jiménez, M A; Solsona, J; Cantos, A; Zamora, J J; Ruiz-Manzano, J; Ausina, V; Domínguez, J
2011-05-01
The aim of the present study was to compare the performance of the interferon (IFN)-γ tests (QuantiFERON®-TB Gold In-Tube (QFT-G-IT) and T-SPOT®.TB) with the tuberculin skin test (TST) in diagnosing tuberculosis (TB) infection in children, and to analyse discordant results. This was a prospective study including 98 children from contact-tracing studies and 68 children with TST indurations ≥ 5 mm recruited during public health screenings. Positive IFN-γ tests results were associated with risk of exposure (p<0.0001). T-SPOT.TB was positive in 11 (78.6%) out of 14 cases with active TB and QFT-G-IT in nine (64.3%) out of 14 cases. Sensitised T-cells against Mycobacterium avium were detected in six out of 12 children not vaccinated with bacille Calmette-Guérin (BCG), a TST induration 5-9 mm in diameter and both IFN-γ tests negative. In concordant IFN-γ tests results, a positive correlation was found (p = 0.0001) between the number of responding cells and the amount of IFN-γ released. However, in discordant IFN-γ tests results this correlation was negative (p = 0.371): an increase in the number of spot-forming cells correlated with a decrease in the amount of IFN-γ released. The use of IFN-γ tests is helpful for the diagnosis of TB infection, avoiding cross-reactions with BCG immunisation and nontuberculous mycobacterial infections. The analysis of highly discordant results requires further investigation to elucidate possible clinical implications.
ERIC Educational Resources Information Center
Jacobson, Neil S.
1978-01-01
Compared two behavioral treatments for marital discord with a nonspecific control and waiting-list control. Behavioral treatments combined problem-solving skills with contingency management procedures, differing only in contracting form, good faith contracts, and quid pro quo contracts. Both behavioral groups improved significantly more than…
Discordance between living and death assemblages as evidence for anthropogenic ecological change
Kidwell, Susan M.
2007-01-01
Mismatches between the composition of a time-averaged death assemblage (dead remains sieved from the upper mixed-zone of the sedimentary column) and the local living community are typically attributed to natural postmortem processes. However, statistical analysis of 73 molluscan data sets from estuaries and lagoons reveals significantly poorer average “live-dead agreement” in settings of documented anthropogenic eutrophication (AE) than in areas where AE and other human impacts are negligible. Taxonomic similarity of paired live and dead species lists declines steadily among areas as a function of AE severity, and, for data sets comprising only adults, rank-order agreement in species abundance drops where AE is suspected. The observed live-dead differences in composition are consistent with eutrophication (anomalous abundance of seagrass-dwellers and/or scarcity of organic-loving species in the death assemblage), suggesting compositional inertia of death assemblages to recent environmental change. Molluscan data sets from open shelf settings (n = 34) also show higher average live-dead discordance in areas of AE. These results indicate that (i) live-dead discordance in surficial grab samples provides valuable evidence for strong anthropogenic modification of benthic communities, (ii) actualistic estimates of the ecological fidelity of molluscan death assemblages tend to be erroneously pessimistic when conducted in nonpristine settings, and (iii) based on their high fidelity in pristine study areas, death assemblages are a promising means of reconstructing otherwise elusive preimpact ecological baselines from sedimentary records. PMID:17965231
Qualitative analysis of an educational intervention with HIV-discordant heterosexual Latino couples.
Pérez-Jiménez, David; Orengo-Aguayo, Rosaura E
2011-12-01
This qualitative analysis elucidates the potential elements of the intervention that may be effective in terms of a) increasing knowledge about HIV/ AIDS in the members of this population; b) increasing the use of male condoms and the practice of mutual masturbation; and c) changing opinions toward male condom use and mutual masturbation. Five heterosexual HIV-discordant couples participated in the adapted intervention, which consisted of four three-hour-long sessions. One month after the intervention, we conducted a qualitative semi-structured interview with every participant to evaluate issues related to the process and content of the activities comprising the intervention, the impact of the intervention, logistics, and recruitment and retention as well as to make a more general evaluation. The information was submitted to qualitative content analysis. After the intervention, participants reported having better attitudes regarding safer sex, particularly in terms of condom use. A reason given by the participants to feel more positive toward condom use and mutual masturbation was that these practices could prevent the infection of the HIV-negative partner. This study provides important evidence of an intervention that promises to be efficacious in preventing some high-risk sexual behaviors among Latino HIV-discordant heterosexual couples. The evidence presented seems to suggest that an intervention that includes basic relevant information about HIV/AIDS, that explains the benefits of condom use and other safer sex options, and that provides effective negotiation and communication strategies could significantly reduce HIV transmission among these couples.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Oestavik, R.E.; Eiklid, K.; Oerstavik, K.H.
1995-03-27
Wiedemann-Beckwith syndrome (WBS) is a syndrome including exomphalos, macroglossia, and generalized overgrowth. The locus has been assigned to 11p15, and genomic imprinting may play a part in the expression of one or more genes involved. Most cases are sporadic. An excess of female monozygotic twins discordant for WBS have been reported, and it has been proposed that this excess could be related to the process of X chromosome inactivation. We have therefore studied X chromosome inactivation in 13-year-old monozygotic twin girls who were discordant for WBS. In addition, both twins had Tourette syndrome. The twins were monochorionic and therefore themore » result of a late twinning process. This has also been the case in previously reported discordant twin pairs with information on placentation. X chromosome inactivation was determined in DNA from peripheral blood cells by PCR analysis at the androgen receptor locus. The affected twin had a completely skewed X inactivation, where the paternal allele was on the active X chromosome in all cells. The unaffected twin had a moderately skewed X inactivation in the same direction, whereas the mother had a random pattern. Further studies are necessary to establish a possible association between the expression of WBS and X chromosome inactivation. 18 refs., 2 figs., 1 tab.« less
Segal, Nancy L
2017-08-01
The late neurologist and author, Oliver Sacks, published an insightful 1986 review of Marjorie Wallace's book, The Silent Twins, in the New York Times. Taking exception to his assertion about Sir Francis Galton, I wrote a letter to the Times' editor. The letter was unpublished, but it brought a wonderful response from Sacks himself that is reproduced and examined. Next, brief reviews of twin research concerning the vanishing twin syndrome (VTS), discordant sex in a monozygotic (MZ) twin pair, and multiple pregnancy outcomes from assisted reproductive technology (ART) are presented. This section is followed by popular coverage of superfetated twins, smoking-discordant co-twins, twins in fashion, Yale University twin hockey players, and a visiting professor who was a conjoined twin.
Clavel, Marie-Annick; Messika-Zeitoun, David; Pibarot, Philippe; Aggarwal, Shivani R; Malouf, Joseph; Araoz, Phillip A; Michelena, Hector I; Cueff, Caroline; Larose, Eric; Capoulade, Romain; Vahanian, Alec; Enriquez-Sarano, Maurice
2013-12-17
With concomitant Doppler echocardiography and multidetector computed tomography (MDCT) measuring aortic valve calcification (AVC) load, this study aimed at defining: 1) independent physiologic/structural determinants of aortic valve area (AVA)/mean gradient (MG) relationship; 2) AVC thresholds best associated with severe aortic stenosis (AS); and 3) whether, in AS with discordant MG, severe calcified aortic valve disease is generally detected. Aortic stenosis with discordant markers of severity, AVA in severe range but low MG, is a conundrum, unresolved by outcome studies. Patients (n = 646) with normal left ventricular ejection fraction AS underwent Doppler echocardiography and AVC measurement by MDCT. On the basis of AVA-indexed-to-body surface area (AVAi) and MG, patients were categorized as concordant severity grading (CG) with moderate AS (AVAi >0.6 cm²/m², MG <40 mm Hg), severe AS (AVAi ≤0.6 cm²/m², MG ≥ 40 mm Hg), discordant-severity-grading (DG) with low-MG (AVAi ≤0.6 cm(2)/m(2), MG <40 mm Hg), or high-MG (AVAi >0.6 cm(2)/m(2), MG ≥40 mm Hg). The MG (discordant in 29%) was strongly determined by AVA and flow but also independently and strongly influenced by AVC-load (p < 0.0001) and systemic arterial compliance (p < 0.0001). The AVC-load (median [interquartile range]) was similar within patients with DG (low-MG: 1,619 [965 to 2,528] arbitrary units [AU]; high-MG: 1,736 [1,209 to 2,894] AU; p = 0.49), higher than CG-moderate-AS (861 [427 to 1,519] AU; p < 0.0001) but lower than CG-severe-AS (2,931 [1,924 to 4,292] AU; p < 0.0001). The AVC-load thresholds separating severe/moderate AS were defined in CG-AS with normal flow (stroke-volume-index >35 ml/m(2)). The AVC-load, absolute or indexed, identified severe AS accurately (area under the curve ≥0.89, sensitivity ≥86%, specificity ≥79%) in men and women. Upon application of these criteria to DG-low MG, at least one-half of the patients were identified as severe calcified
Díaz-González, Lorena; Quiroz-Ruiz, Alfredo
2014-01-01
Using highly precise and accurate Monte Carlo simulations of 20,000,000 replications and 102 independent simulation experiments with extremely low simulation errors and total uncertainties, we evaluated the performance of four single outlier discordancy tests (Grubbs test N2, Dixon test N8, skewness test N14, and kurtosis test N15) for normal samples of sizes 5 to 20. Statistical contaminations of a single observation resulting from parameters called δ from ±0.1 up to ±20 for modeling the slippage of central tendency or ε from ±1.1 up to ±200 for slippage of dispersion, as well as no contamination (δ = 0 and ε = ±1), were simulated. Because of the use of precise and accurate random and normally distributed simulated data, very large replications, and a large number of independent experiments, this paper presents a novel approach for precise and accurate estimations of power functions of four popular discordancy tests and, therefore, should not be considered as a simple simulation exercise unrelated to probability and statistics. From both criteria of the Power of Test proposed by Hayes and Kinsella and the Test Performance Criterion of Barnett and Lewis, Dixon test N8 performs less well than the other three tests. The overall performance of these four tests could be summarized as N2≅N15 > N14 > N8. PMID:24737992
Verma, Surendra P; Díaz-González, Lorena; Rosales-Rivera, Mauricio; Quiroz-Ruiz, Alfredo
2014-01-01
Using highly precise and accurate Monte Carlo simulations of 20,000,000 replications and 102 independent simulation experiments with extremely low simulation errors and total uncertainties, we evaluated the performance of four single outlier discordancy tests (Grubbs test N2, Dixon test N8, skewness test N14, and kurtosis test N15) for normal samples of sizes 5 to 20. Statistical contaminations of a single observation resulting from parameters called δ from ±0.1 up to ±20 for modeling the slippage of central tendency or ε from ±1.1 up to ±200 for slippage of dispersion, as well as no contamination (δ = 0 and ε = ±1), were simulated. Because of the use of precise and accurate random and normally distributed simulated data, very large replications, and a large number of independent experiments, this paper presents a novel approach for precise and accurate estimations of power functions of four popular discordancy tests and, therefore, should not be considered as a simple simulation exercise unrelated to probability and statistics. From both criteria of the Power of Test proposed by Hayes and Kinsella and the Test Performance Criterion of Barnett and Lewis, Dixon test N8 performs less well than the other three tests. The overall performance of these four tests could be summarized as N2≅N15 > N14 > N8.
Discordance in the diagnosis of diabetes: Comparison between HbA1c and fasting plasma glucose.
Ho-Pham, Lan T; Nguyen, Uyen D T; Tran, Truong X; Nguyen, Tuan V
2017-01-01
HbA1c has been introduced as a complementary diagnostic test for diabetes, but its impact on disease prevalence is unknown. This study evaluated the concordance between HbA1c and fasting plasma glucose (FPG) in the diagnosis of diabetes in the general population. The study was designed as a population based investigation, with participants being sampled from the Ho Chi Minh City, Vietnam. Blood samples were collected after overnight fasting and analyzed within 4 hours after collection. HbA1c was measured with high pressure liquid chromatography (Arkray Adams, Japan). FPG was measured by the hexokinase method (Advia Autoanalyzer; Bayer Diagnostics, Germany). Diabetes was defined as HbA1c ≥ 6.5% or FPG ≥ 7.0 mmol/L. Prediabetes was classified as HbA1c between 5.7% and 6.4%. The study included 3523 individuals (2356 women) aged 30 years and above. Based on the HbA1c test, the prevalence of diabetes and prediabetes was 9.7% (95%CI, 8.7-10.7%; n = 342) and 34.6% (33.0-36.2; n = 1219), respectively. Based on the FPG test, the prevalence of diabetes and prediabetes was 6.3% (95%CI, 5.5-7.2%; n = 223) and 12.1% (11.1-13.2; n = 427). Among the 427 individuals identified by FPG as "pre-diabetes", 28.6% were classified as diabetes by HbA1c test. The weighted kappa statistic of concordance between HbA1c and FPG was 0.55, with most of the discordance being in the prediabetes group. These data indicate that there is a significant discordance in the diagnosis of diabetes between FPG and HbA1c measurements, and the discordance could have significant impact on clinical practice. FPG appears to underestimate the burden of undiagnosed diabetes.
Discordant U waves in the setting of hyperkalaemia.
Chhabra, Lovely; Spodick, David H
2013-07-04
Physiological U wave genesis occurs likely secondary to either late repolarisation of Purkinje fibres, or late repolarisation of some myocardial cells and/or delayed after depolarisation of the ventricular wall occurring during ventricular filling. Hypokalaemia has a well-known association with pathological 'U wave' which actually combines with the T wave (TU complex) and results from slowing of phase 3 of the action potential with resultant electrical interaction between the three myocardial layers. U waves usually tend to disappear in the setting of hyperkalaemia. We report an unusual case where hyperkalaemia and discordant U waves coexisted. We believe that this may have occurred as a result of partial clinical adaptation of cardiac myocytes to the long-standing effects of hyperkalaemia as the patient had underlying history of chronic kidney disease. We also discuss the possible mechanisms of the U wave genesis and the importance of different U wave morphologies encountered in the real clinical practice.
ERIC Educational Resources Information Center
Lehn, Hanne; Derks, Eske M.; Hudziak, James J.; Heutink, Peter; van Beijsterveldt, Toos; Boomsma, Dorret I.
2007-01-01
Objective: To study familial and nonfamilial environmental influences on attention problems and attention-deficit/hyperactivity disorder (ADHD) in monozygotic twins discordant and concordant-high and low for these traits. Method: Ninety-five twin pairs from The Netherlands Twin Register were selected. Longitudinal survey data were collected at 1,…
Hannan, Enda J; O'Leary, Donal P; MacNally, Stephen P; Kay, Elaine W; Farrell, Michael A; Morris, Patrick G; Power, Colm P; Hill, Arnold D K
2017-12-01
To compare BRAF V600E status of primary melanoma and brain metastases to assess for discordance by cross-sectional study, and to evaluate clinical implications on BRAF inhibitor therapy.Brain metastases are common in patients with advanced melanoma. Between 40% and 60% of melanomas demonstrate BRAF mutations, BRAF V600E being most common. Selective BRAF inhibitor therapy has shown improvement in outcome in patients with melanoma. It has been demonstrated that not all metastatic lesions carry the same BRAF mutation status as the primary, but the frequency in which discordance occurs remains unclear. Establishing this may have implications in the use of BRAF inhibitors in patients with melanoma brain metastases.Patients who underwent metastectomy for melanoma brain metastases were identified using our local histopathology database. A review of histology of the primary lesion and the metastasis was performed for each patient, assessing for BRAF mutation status discordance.Fourty-two patients who underwent a brain metastectomy following excision of a melanoma primary were identified over a 7-year period. Median survival was 9 months. The median Breslow thickness for the primary lesion was 3.4 mm. Six patients (14%) had discrepancy between the BRAF status of a melanoma primary and metastatic lesion. Of these 6 patients, 3 had a BRAF mutation positive primary with a BRAF mutation negative metastatic lesion, while the other 3 had a BRAF mutation negative primary with BRAF mutation positive metastasis.There is an important discordance rate in the BRAF mutation status of melanoma primaries versus brain metastases.
Starkman, M N; Schteingart, D E; Schork, M A
1992-11-01
Cushing's Disease is often associated with a depressive syndrome, with mood, vegetative, and cognitive abnormalities of variable severity. In 11 patients with (pituitary ACTH-dependent) Cushing's disease (10 women, 1 man), we studied the relationship between severity of the depressive syndrome and concordance of changes in ACTH and beta-lipotropin/beta-endorphin (beta-LPH/beta-E) levels at baseline and in response to metyrapone and dexamethasone. For each condition, blood samples were drawn at 0800h, 1200h, 1600h, and 2200h. Six patients were categorized as mildly depressed (mean [+/- SD] depressed mood score = 0.17 +/- 0.4; modified Hamilton Depression scale score = 7.6 +/- 4.5) and five as severely depressed (mean depressed mood score = 2.4 +/- 0.5; modified Hamilton Depression scale score = 15 +/- 5.6) (p < 0.05). ACTH and beta-LPH/beta-E were measured by radioimmunoassay. For each experimental condition, changes in levels were scored as concordant if the two peptides moved in parallel between sampling points. There was a relationship between greater severity of depression and more frequent discordant changes in ACTH and beta-LPH/beta-E levels: The six patients with mild depression exhibited 23 concordant and 3 discordant change patterns, while the five patients with severe depression showed 8 concordant and 15 discordant patterns. The mean percentage of concordant patterns per patient differed significantly between the two groups (mildly depressed = 90.0 +/- 16.7; severely depressed = 34.6 +/- 8.7 (p < 0.001). When each study condition was examined separately, differences in the frequency of concordance between the groups reached significance during the post-metyrapone phase and with 8.0 mg dexamethasone administration.(ABSTRACT TRUNCATED AT 250 WORDS)
Leskinen, Tuija; Kujala, Urho M
2015-06-01
We are lacking very long-term and controlled intervention studies investigating the effects of habitual physical activity on health-related factors. To address this gap, we performed a natural experiment by identifying same-sex twin pairs in which the co-twins of each pair differed with respect to leisure-time physical-activity habits throughout their adult life. Our criterion for the discordance was that the same co-twin had a higher leisure time-activity volume than that of the other member of the pair at the majority -- if not all -- of the follow-up time points according to reported/interviewed physical-activity data. Overall, we identified and conducted multidimensional health-related measurements (including fitness, body composition, cardiometabolic risk factor levels, bone and arterial status, and exercise motivation) of 16 twin pairs (seven monozygotic (MZ) and nine dizygotic (DZ) pairs, mean age 60 years) who had persistent discordance in leisure-time physical-activity habits over three decades (TWINACTIVE study). In our discordant-pair study design, after adjusting for sequence-level genes, both systemic-level metabolic, and site-specific structural findings differed significantly in the pairwise analysis in MZ pairs only. These findings included intrapair differences in accumulated fat depots and structure of heart, arteries, and bones. In addition, our study revealed intrapair differences in metabolic and regulatory pathways, which may partly explain the mechanistic links between long-term physical activity, phenotypic changes, and decreased risk of cardiometabolic diseases.
Qualitative Analysis of an Educational Intervention with HIV-Discordant Heterosexual Latino Couples
Pérez-Jiménez, David; Orengo-Aguayo, Rosaura E.
2012-01-01
Objective This qualitative analysis elucidates the potential elements of the intervention that may be effective in terms of a) increasing knowledge about HIV/AIDS in the members of this population; b) increasing the use of male condoms and the practice of mutual masturbation; and c) changing opinions toward male condom use and mutual masturbation. Methods Five heterosexual HIV-discordant couples participated in the adapted intervention, which consisted of four three-hour-long sessions. One month after the intervention, we conducted a qualitative semi-structured interview with every participant to evaluate issues related to the process and content of the activities comprising the intervention, the impact of the intervention, logistics, and recruitment and retention as well as to make a more general evaluation. The information was submitted to qualitative content analysis. Results After the intervention, participants reported having better attitudes regarding safer sex, particularly in terms of condom use. A reason given by the participants to feel more positive toward condom use and mutual masturbation was that these practices could prevent the infection of the HIV-negative partner. Conclusion This study provides important evidence of an intervention that promises to be efficacious in preventing some high-risk sexual behaviors among Latino HIV-discordant heterosexual couples. The evidence presented seems to suggest that an intervention that includes basic relevant information about HIV/AIDS, that explains the benefits of condom use and other safer sex options, and that provides effective negotiation and communication strategies could significantly reduce HIV transmission among these couples. PMID:22263299
Roifman, Maian; Choufani, Sanaa; Turinsky, Andrei L; Drewlo, Sascha; Keating, Sarah; Brudno, Michael; Kingdom, John; Weksberg, Rosanna
2016-01-01
Intrauterine growth restriction (IUGR), which refers to reduced fetal growth in the context of placental insufficiency, is etiologically heterogeneous. IUGR is associated not only with perinatal morbidity and mortality but also with adult-onset disorders, such as cardiovascular disease and diabetes, posing a major health burden. Placental epigenetic dysregulation has been proposed as one mechanism that causes IUGR; however, the spectrum of epigenetic pathophysiological mechanisms leading to IUGR remains to be elucidated. Monozygotic monochorionic twins are particularly affected by IUGR, in the setting of severe discordant growth. Because monozygotic twins have the same genotype at conception and a shared maternal environment, they provide an ideal model system for studying epigenetic dysregulation of the placenta. We compared genome-wide placental DNA methylation patterns of severely growth-discordant twins to identify novel candidate genes for IUGR. Snap-frozen placental samples for eight severely growth-discordant monozygotic monochorionic twin pairs were obtained at delivery from each twin. A high-resolution DNA methylation array platform was used to identify methylation differences between IUGR and normal twins. Our analysis revealed differentially methylated regions in the promoters of eight genes: DECR1, ZNF300, DNAJA4, CCL28, LEPR, HSPA1A/L, GSTO1, and GNE. The largest methylation differences between the two groups were in the promoters of DECR1 and ZNF300. The significance of these group differences was independently validated by bisulfite pyrosequencing, implicating aberrations in fatty acid beta oxidation and transcriptional regulation, respectively. Further analysis of the array data identified methylation changes most prominently affecting the Wnt and cadherin pathways in the IUGR cohort. Our results suggest that IUGR in monozygotic twins is associated with impairments in lipid metabolism and transcriptional regulation as well as cadherin and Wnt
Winchester, David E; Wolinsky, David; Beyth, Rebecca J; Shaw, Leslee J
2016-05-01
Appropriate use criteria (AUC) assist health care professionals in making decisions about procedures and diagnostic testing. In some cases, multiple AUC exist for a single procedure or test. To date, the extent of agreement between multiple AUC has not been evaluated. To measure discordance between the American College of Cardiology Foundation (ACCF) AUC and the American College of Radiology (ACR) Appropriateness Criteria for gauging the appropriateness of nuclear myocardial perfusion imaging. Retrospective cohort study at an academically affiliated Veterans Affairs medical center. Participants were Veteran patients who underwent nuclear myocardial perfusion imaging between December 2010 and July 2011 with rating of appropriateness by the ACCF and ACR criteria. Analysis was performed in March 2015. The primary outcome was the agreement of appropriateness category as measured by κ statistic. The secondary outcome was a comparison of nuclear myocardial perfusion imaging results and frequency of ischemia across appropriateness categories for the 2 rating methods. Of 67 indications in the ACCF AUC, 35 (52.2%) could not be matched to an ACR rating, 18 (26.9%) had the same appropriateness category, and 14 (20.9%) disagreed on appropriateness. The study cohort comprised 592 individuals. Their mean (SD) age was 62.6 (9.4) years, and 570 of 592 (96.2%) were male. When applied to the patient cohort, 111 patients (18.8%) could not be matched to an ACR rating, 349 patients (59.0%) had the same appropriateness category for the ACR and ACCF methods, and 132 patients (22.3%) were discordant. Overall, the agreement of appropriateness between the 2 methods was poor (κ = 0.34, P < .001). Ischemia was rare among patients rated as "inappropriate" by the ACCF AUC (1 of 39 patients [2.6%]), while ischemia was more common among patients rated as "usually not appropriate" by the ACR Appropriateness Criteria (14 of 80 patients [17.5%]). Substantial discordance may exist between
Lutalo, Tom; Musoke, Richard; Kong, Xiangrong; Makumbi, Fred; Serwadda, David; Nalugoda, Fred; Kigozi, Godfrey; Sewankambo, Nelson; Sekasanvu, Joseph; Wawer, Maria; Gray, Ronald
2013-10-01
The risk of HIV associated with hormonal contraceptives is controversial. We assessed hormonal contraceptive use and HIV incidence in HIV-discordant couples in Rakai, Uganda. HIV-discordant couples were retrospectively identified from a cohort between 1999 and 2009. Hormonal contraception included oral contraception, depomedroxyprogesterone acetate (DMPA), and implants (Norplant). Poisson regression estimated adjusted incidence rate ratios (adjIRRs) associated with hormonal contraceptive methods. A case-control subanalysis estimated odds ratios (ORs) of HIV associated with hormonal contraceptive, adjusted for viral load and age. We identified 190 male HIV-positive/female HIV-negative (M+F-) and 159 male HIV- negative/female HIV-positive (M-F+) couples not using antiretroviral therapy or condoms. Female HIV incidence was 5.8/100 person-years (py) among nonhormonal contraceptive users, 12.0/100 py among oral contraceptive users [adjIRR 2.65, 95% confidence interval (CI) 0.82-8.60], 4.5 among Norplant users (adjIRR: 0.89, 95% CI 0.11-7.10), and 7.5/100 py among DMPA users (adjIRR 1.42, 95% CI 0.60-3.36). Male HIV incidence was 7.4/100 py during nonhormonal contraceptive use, 16.5/100 py during female oral contraceptive use (adjIRR 2.52, 95% CI 0.49-12.95), and 4.9/100 py with DMPA use (adjIRR 0.57, 95% CI 0.19-1.70). The number of female seroconverters was three among oral contraceptive users, one among Norplant users, and seven among DMPA users. Male seroconverters were two during female oral contraceptive use, none with Norplant use, and three with DMPA use. In a nested case-control analysis after adjustment for HIV viral load, the adjOR associated with oral contraceptive use was 1.59 (95% CI 0.32-97.85) for M+F- and 2.11 (95% CI 0.18-25.26) for M-F+ couples. For DMPA use, the adjOR was 1.44 (95% CI 0.46-4.51) for M+F- and 1.40 (95% CI 0.30-6.49) for M-F+ couples. We did not observe significant risk of HIV acquisition or transmission with oral contraceptives or DMPA
Transcriptional Signatures of Sleep Duration Discordance in Monozygotic Twins.
Watson, N F; Buchwald, D; Delrow, J J; Altemeier, W A; Vitiello, M V; Pack, A I; Bamshad, M; Noonan, C; Gharib, S A
2017-01-01
Habitual short sleep duration is associated with adverse metabolic, cardiovascular, and inflammatory effects. Co-twin study methodologies account for familial (eg, genetics and shared environmental) confounding, allowing assessment of subtle environmental effects, such as the effect of habitual short sleep duration on gene expression. Therefore, we investigated gene expression in monozygotic twins discordant for actigraphically phenotyped habitual sleep duration. Eleven healthy monozygotic twin pairs (82% female; mean age 42.7 years; SD = 18.1), selected based on subjective sleep duration discordance, were objectively phenotyped for habitual sleep duration with 2 weeks of wrist actigraphy. Peripheral blood leukocyte (PBL) RNA from fasting blood samples was obtained on the final day of actigraphic measurement and hybridized to Illumina humanHT-12 microarrays. Differential gene expression was determined between paired samples and mapped to functional categories using Gene Ontology. Finally, a more comprehensive gene set enrichment analysis was performed based on the entire PBL transcriptome. The mean 24-hour sleep duration of the total sample was 439.2 minutes (SD = 46.8 minutes; range 325.4-521.6 minutes). Mean within-pair sleep duration difference per 24 hours was 64.4 minutes (SD = 21.2; range 45.9-114.6 minutes). The twin cohort displayed distinctive pathway enrichment based on sleep duration differences. Habitual short sleep was associated with up-regulation of genes involved in transcription, ribosome, translation, and oxidative phosphorylation. Unexpectedly, genes down-regulated in short sleep twins were highly enriched in immuno-inflammatory pathways such as interleukin signaling and leukocyte activation, as well as developmental programs, coagulation cascade, and cell adhesion. Objectively assessed habitual sleep duration in monozygotic twin pairs appears to be associated with distinct patterns of differential gene expression and pathway enrichment. By
ERIC Educational Resources Information Center
Hellström, Lisa; Beckman, Linda; Hagquist, Curt
2013-01-01
The current study examined concordance and discordance between a measure of bullying and measures of peer aggression with respect to the number of students identified as victims. Swedish adolescents (N = 1,760) completed a web-based questionnaire. A measure of bullying and measures of peer aggression were compared in order to elucidate the unique…
ERIC Educational Resources Information Center
Medicus, Jennifer
2012-01-01
Children and adolescents who are growing up gay, lesbian, bisexual, gender nonconforming, or gender discordant experience unique developmental challenges. They are at risk for certain mental health problems, many of which are significantly correlated with stigma and prejudice. Mental health professionals have an important role to play in fostering…
Millerón, M; López de Heredia, U; Lorenzo, Z; Alonso, J; Dounavi, A; Gil, L; Nanos, N
2013-03-01
Spatial discordance between primary and effective dispersal in plant populations indicates that postdispersal processes erase the seed rain signal in recruitment patterns. Five different models were used to test the spatial concordance of the primary and effective dispersal patterns in a European beech (Fagus sylvatica) population from central Spain. An ecological method was based on classical inverse modelling (SSS), using the number of seed/seedlings as input data. Genetic models were based on direct kernel fitting of mother-to-offspring distances estimated by a parentage analysis or were spatially explicit models based on the genotype frequencies of offspring (competing sources model and Moran-Clark's Model). A fully integrated mixed model was based on inverse modelling, but used the number of genotypes as input data (gene shadow model). The potential sources of error and limitations of each seed dispersal estimation method are discussed. The mean dispersal distances for seeds and saplings estimated with these five methods were higher than those obtained by previous estimations for European beech forests. All the methods show strong discordance between primary and effective dispersal kernel parameters, and for dispersal directionality. While seed rain was released mostly under the canopy, saplings were established far from mother trees. This discordant pattern may be the result of the action of secondary dispersal by animals or density-dependent effects; that is, the Janzen-Connell effect. © 2013 Blackwell Publishing Ltd.
Dandekar, Monisha; Lowe, Lori; Fullen, Douglas R; Johnson, Timothy M; Sabel, Michael S; Wong, Sandra L; Patel, Rajiv M
2014-10-01
Sentinel lymph node (SLN) status currently represents the single most important prognostic factor in clinically localized melanoma and is widely used in patients with melanoma at significant risk for nodal micrometastasis. Although several studies have looked at the rates and implications of inaccuracies in the histopathologic diagnosis of melanocytic lesions, accuracy in the histologic interpretation of the SLN in melanoma has not been addressed. The goal of this study was to determine the rates of discordance in the histopathologic evaluation of the SLN and the potential clinical impact on patients referred to a comprehensive melanoma center. A prospectively collected database was queried for melanoma patients who had SLN biopsies performed at outside institutions before referral to the University of Michigan Multidisciplinary Melanoma Program between 2006 and 2009. These cases were reviewed and clinical follow-up obtained. After internal review of the SLN material, 13 (8 %) of 167 cases had major discrepancies in diagnosis that impacted patient management and prognosis. The disease of five patients was subsequently downstaged and the disease of eight patients was upstaged after internal review of the SLNs and reversal in diagnoses. There appears to be a small yet significant rate of discordance in diagnosis of the SLN for melanoma after expert histopathologic review. The implications of this discordance and revision of diagnosis is substantial. Expert histopathologic review of the SLN warrants consideration to provide the most accurate prognostic information and optimal patient care.
The Effects of Oncologist Implicit Racial Bias in Racially Discordant Oncology Interactions
Dovidio, John F.; Gonzalez, Richard; Albrecht, Terrance L.; Chapman, Robert; Foster, Tanina; Harper, Felicity W.K.; Hagiwara, Nao; Hamel, Lauren M.; Shields, Anthony F.; Gadgeel, Shirish; Simon, Michael S.; Griggs, Jennifer J.; Eggly, Susan
2016-01-01
Purpose Health providers’ implicit racial bias negatively affects communication and patient reactions to many medical interactions. However, its effects on racially discordant oncology interactions are largely unknown. Thus, we examined whether oncologist implicit racial bias has similar effects in oncology interactions. We further investigated whether oncologist implicit bias negatively affects patients’ perceptions of recommended treatments (i.e., degree of confidence, expected difficulty). We predicted oncologist implicit bias would negatively affect communication, patient reactions to interactions, and, indirectly, patient perceptions of recommended treatments. Methods Participants were 18 non-black medical oncologists and 112 black patients. Oncologists completed an implicit racial bias measure several weeks before video-recorded treatment discussions with new patients. Observers rated oncologist communication and recorded interaction length of time and amount of time oncologists and patients spoke. Following interactions, patients answered questions about oncologists’ patient-centeredness and difficulty remembering contents of the interaction, distress, trust, and treatment perceptions. Results As predicted, oncologists higher in implicit racial bias had shorter interactions, and patients and observers rated these oncologists’ communication as less patient-centered and supportive. Higher implicit bias also was associated with more patient difficulty remembering contents of the interaction. In addition, oncologist implicit bias indirectly predicted less patient confidence in recommended treatments, and greater perceived difficulty completing them, through its impact on oncologists’ communication (as rated by both patients and observers). Conclusion Oncologist implicit racial bias is negatively associated with oncologist communication, patients’ reactions to racially discordant oncology interactions, and patient perceptions of recommended treatments
Monogamy relations of nonclassical correlations for multi-qubit states
NASA Astrophysics Data System (ADS)
Cheng, Shuming; Liu, Lijun
2018-07-01
Nonclassical correlations have been found useful in many quantum information processing tasks, and various measures have been proposed to quantify these correlations. In this work, we mainly study one of nonclassical correlations, called measurement-induced nonlocality (MIN). First, we establish a close connection between this nonlocal effect and the Bell nonlocality for two-qubit states. Then, we derive a tight monogamy relation of MIN for any pure three-qubit state and provide an alternative way to obtain similar monogamy relations for other nonclassical correlation measures, including squared negativity, quantum discord, and geometric quantum discord. Finally, we find that the tight monogamy relation of MIN is violated by some mixed three-qubit states, however, a weaker monogamy relation of MIN for mixed states and even multi-qubit states is still obtained.
Testing for Neuropsychological Endophenotypes in Siblings Discordant for ADHD
Bidwell, L. Cinnamon; Willcutt, Erik G.; DeFries, John C.; Pennington, Bruce F.
2007-01-01
Objective Neurocognitive deficits associated with attention deficit-hyperactivity disorder (ADHD) may be useful intermediate endophenotypes for determining specific genetic pathways that contribute to ADHD. Methods This study administered 17 measures from prominent neuropsychological theories of ADHD (executive function, processing speed, arousal regulation and motivation/delay aversion) in dizygotic (DZ) twin pairs discordant for ADHD and control twin pairs (ages 8–18) in order to compare performance between twins affected with ADHD (n = 266), their unaffected co-twins (n = 228), and control children from twin pairs without ADHD or learning difficulties (n = 332). Results ADHD subjects show significant impairment on executive function, processing speed, and response variability measures compared to control subjects. Unaffected cotwins of ADHD subjects are significantly impaired on nearly all the same measures as their ADHD siblings, even when subclinical symptoms of ADHD are controlled. Conclusion Executive function, processing speed, and response variability deficits may be useful endophenotypes for genetic studies of ADHD. PMID:17585884
Concordant and discordant alcohol, tobacco, and marijuana use as predictors of marital dissolution
Leonard, Kenneth E.; Smith, Philip H.; Homish, Gregory G.
2014-01-01
Objective This study examined concordant and discrepant alcohol, tobacco, and marijuana use among couples to determine whether they predicted marital separation/divorce over nine years. Method The study recruited 634 couples as they applied for their marriage license and assessed them at that time, and re-assessed them with mailed questionnaires at their 1st, 2nd, 4th, 7th, and 9th anniversaries. Approximately 60% of the men and women were European-American, and approximately 1/3 were African-American. The frequency of drinking to intoxication and binge drinking (more than 5 drinks in an occasion) were assessed, as were the use of cigarettes and marijuana. At each assessment, each member of the couple was asked about the occurrence of marital separations and divorce. Results Bivariate analyses indicated that tobacco and marijuana use, whether discrepant or concordant, were associated with marital disruptions. However, discrepant heavy drinking was associated with disruptions but concordant heavy drinking was not. Concordant and discordant marijuana use were not associated with divorce when analyses controlled for alcohol and tobacco use. Concordant and discordant tobacco use was not associated with divorce when analyses controlled for sociodemographic and personality factors. However, discrepant alcohol use was related to divorce after controlling for the other substances in one analysis and after controlling for the sociodemographic factors in a separate analysis. Conclusions Tobacco and marijuana use were related to divorce through their associations with other variables. However, results suggested that discrepant alcohol use may lead to marital disruptions and should be addressed with couples seeking marital treatment. PMID:24128287
Bornovalova, Marina A.; Huibregtse, Brooke M.; Hicks, Brian M.; Keyes, Margaret; McGue, Matt; Iacono, William
2012-01-01
We used a longitudinal twin design to examine the causal association between sexual, emotional, and physical abuse in childhood (before age 18) and borderline personality disorder (BPD) traits at age 24 using a discordant twin design and biometric modeling. Additionally, we examined the mediating and moderating effects of symptoms of childhood externalizing and internalizing disorders on the link between childhood abuse and BPD traits. Although childhood abuse, BPD traits, and internalizing and externalizing symptoms were all correlated, the discordant twin analyses and biometric modeling showed little to no evidence that consistent with a causal effect of childhood abuse on BPD traits. Instead, our results indicate that the association between childhood abuse and BPD traits stems from common genetic influences that, in some cases, also overlap with internalizing and externalizing disorders. These findings are inconsistent with the widely held assumption that childhood abuse causes BPD, and suggests that BPD traits in adulthood are better accounted for by heritable vulnerabilities to internalizing and externalizing disorders. PMID:22686871
McWilliams, Daniel F; Ferguson, Eamonn; Young, Adam; Kiely, Patrick D W; Walsh, David A
2016-12-13
Rheumatoid arthritis (RA) disease activity is often measured using the 28-joint Disease Activity Score (DAS28). We aimed to identify and independently verify subgroups of people with RA that may be discordant with respect to self-reported and objective disease state, with potentially different clinical needs. Data were derived from three cohorts: (1) the Early Rheumatoid Arthritis Network (ERAN) and the British Society for Rheumatology Biologics Register (BSRBR), (2) those commencing tumour necrosis factor (TNF)-α inhibitors and (3) those using non-biologic drugs. In latent class analysis, we used variables related to pain, central pain mechanisms or inflammation (pain, vitality, mental health, erythrocyte sedimentation rate, swollen joint count, tender joint count, visual analogue scale of general health). Clinically relevant outcomes were examined. Five, four and four latent classes were found in the ERAN, BSRBR TNF inhibitor and non-biologic cohorts, respectively. The proportions of people assigned with >80% probability into latent classes were 76%, 58% and 72% in the ERAN, TNF inhibitor and non-biologic cohorts, respectively. The latent classes displayed either concordance between measures indicative of mild, moderate or severe disease activity; discordantly worse patient-reported measures despite less markedly elevated inflammation; or discordantly less severe patient-reported measures despite elevated inflammation. Latent classes with discordantly worse patient-reported measures represented 12%, 40% and 21% of the ERAN, TNF inhibitor and non-biologic cohorts, respectively; contained more females; and showed worse function. In those latent classes with worse scores at baseline, DAS28 and function improved over 1 year (p < 0.001 for all comparisons), and scores differed less at follow-up than at baseline. Discordant latent classes can be identified in people with RA, and these findings are robust across three cohorts with varying disease duration and
Kim, Jung H; Rhee, Ye-Y; Bae, Jeong-M; Kwon, Hyeong-J; Cho, Nam-Y; Kim, Mi J; Kang, Gyeong H
2013-07-01
Although the presence of MLH1 methylation in microsatellite-unstable colorectal cancer generally indicates involvement of the CpG island methylator phenotype (CIMP) in the development of the tumor, these two conditions do not always correlate. A minority of microsatellite-unstable colorectal cancers exhibit discordance between CIMP and MLH1 methylation statuses. However, the clinicopathological features of such microsatellite-unstable colorectal cancers with discrepant MLH1 methylation and CIMP statuses remain poorly studied. Microsatellite-unstable colorectal cancers (n=220) were analyzed for CIMP and MLH1 methylation statuses using the MethyLight assay. Based on the combinatorial CIMP and MLH1 methylation statuses, the microsatellite-unstable colorectal cancers were grouped into four subtypes (CIMP-high (CIMP-H) MLH1 methylation-positive (MLH1m+), CIMP-H MLH1 methylation-negative, CIMP-low/0 (CIMP-L/0) MLH1m+, and CIMP-L/0 MLH1 methylation-negative), which were compared in terms of their associations with clinicopathological and molecular features. The CIMP-L/0 MLH1 methylation-negative and CIMP-H MLH1m+ subtypes were predominant, comprising 63.6 and 24.1% of total microsatellite-unstable colorectal cancers, respectively. The discordant subtypes, CIMP-H MLH1 methylation-negative and CIMP-L/0 MLH1m+, were found in 5 and 7% of microsatellite-unstable colorectal cancers, respectively. The CIMP-H MLH1 methylation-negative subtype exhibited elevated incidence rates in male patients and was associated with larger tumor size, more frequent loss of MSH2 expression, increased frequency of KRAS mutation, and advanced cancer stage. The CIMP-L/0 MLH1m+ subtype was associated with onset at an earlier age, a predominance of MLH1 loss, and earlier cancer stage. None of the CIMP-L/0 MLH1m+ subtype patients succumbed to death during the follow-up. Our findings suggest that the discordant subtypes of colorectal cancers exhibit distinct clinicopathological and molecular features
Quantum Monte Carlo tunneling from quantum chemistry to quantum annealing
NASA Astrophysics Data System (ADS)
Mazzola, Guglielmo; Smelyanskiy, Vadim N.; Troyer, Matthias
2017-10-01
Quantum tunneling is ubiquitous across different fields, from quantum chemical reactions and magnetic materials to quantum simulators and quantum computers. While simulating the real-time quantum dynamics of tunneling is infeasible for high-dimensional systems, quantum tunneling also shows up in quantum Monte Carlo (QMC) simulations, which aim to simulate quantum statistics with resources growing only polynomially with the system size. Here we extend the recent results obtained for quantum spin models [Phys. Rev. Lett. 117, 180402 (2016), 10.1103/PhysRevLett.117.180402], and we study continuous-variable models for proton transfer reactions. We demonstrate that QMC simulations efficiently recover the scaling of ground-state tunneling rates due to the existence of an instanton path, which always connects the reactant state with the product. We discuss the implications of our results in the context of quantum chemical reactions and quantum annealing, where quantum tunneling is expected to be a valuable resource for solving combinatorial optimization problems.
Knowles, Lacey L; Klimov, Pavel B
2011-11-01
With the increased availability of multilocus sequence data, the lack of concordance of gene trees estimated for independent loci has focused attention on both the biological processes producing the discord and the methodologies used to estimate phylogenetic relationships. What has emerged is a suite of new analytical tools for phylogenetic inference--species tree approaches. In contrast to traditional phylogenetic methods that are stymied by the idiosyncrasies of gene trees, approaches for estimating species trees explicitly take into account the cause of discord among loci and, in the process, provides a direct estimate of phylogenetic history (i.e. the history of species divergence, not divergence of specific loci). We illustrate the utility of species tree estimates with an analysis of a diverse group of feather mites, the pinnatus species group (genus Proctophyllodes). Discord among four sequenced nuclear loci is consistent with theoretical expectations, given the short time separating speciation events (as evident by short internodes relative to terminal branch lengths in the trees). Nevertheless, many of the relationships are well resolved in a Bayesian estimate of the species tree; the analysis also highlights ambiguous aspects of the phylogeny that require additional loci. The broad utility of species tree approaches is discussed, and specifically, their application to groups with high speciation rates--a history of diversification with particular prevalence in host/parasite systems where species interactions can drive rapid diversification.
Salvy, S-J; Feda, D M; Epstein, L H; Roemmich, J N
2017-04-01
This study examines the contribution of best friends' weight and the peer social context (time spent alone versus with friends) as sources of unshared environment associated with variability in weight and health behaviors among weight-discordant siblings. Pairs of same-sex biologic siblings (N=40 pairs; ages 13-17) were originally recruited as part of a study evaluating putative factors contributing to differences in adiposity among weight-discordant siblings. Siblings were asked to bring their best friends to the laboratory and siblings and friends' height and weight were objectively measured. Siblings also completed multi-pass dietary recalls to assess energy intake and sugar sweetened beverage (SSB) consumption. Siblings' physical activity was measured using accelerometry. Experience sampling methodology was used to assess sedentary behaviors/screen time and the number of occasions siblings spent alone and in the presence of friends. Multilevel models were used to estimate the relationships between predictors (best friends' zBMI, time spent alone or with friends) and outcomes (siblings' zBMI and obesity-related health behaviors). Best friends' zBMI was the best predictor of participants' zBMI, even when controlling for child's birth weight. Best friends' weight (zBMI) further predicted participants' SSB intake and time engaged in sedentary behaviors. Being active with friends was positively associated with participants' overall physical activity, whereas spending time alone was negatively associated with accelerometer counts regardless of siblings' adiposity. A friends' weight and the social context are unshared environmental factors associated with variability in adiposity among biologically-related weight-discordant siblings.
Chuang, Jody C.; Shrager, Joseph B.; Wakelee, Heather A.; Neal, Joel W.
2016-01-01
Purpose Adenocarcinoma remains the most common subtype of lung cancer in the United States. Most patients present with tumors that are invasive and often metastatic, but some patients develop multiple precursor in-situ or minimally invasive adenocarcinoma tumors which can be synchronous and metachronous. These precursor lesions harbor the same spectrum of genetic mutations found in pure-invasive adenocarcinomas, such as EGFR, KRAS and p53 mutations. It is less clear, however, if separate lesions in patients who present with multifocal disease share common underlying genetic driver mutations. Methods Here we review the relevant literature on molecular driver alterations in adenocarcinoma precursor lesions. We then report four cases with multifocal EGFR mutant adenocarcinomas in whom we performed molecular testing on 2 separate lesions. Findings In two of these patients, the mutations are concordant, and in two cases the mutations are discordant. A review of the literature demonstrates increasing evidence that lesions with discordant mutations may confer a more favorable prognosis, since they are unlikely to represent metastases. Implications Our findings suggest that the emergence of the dominant EGFR driver alteration is often independent between lesions in patients with multifocal adenocarcinomas, and thus the same targeted therapy may not be effective for all lesions. However, genetic testing of multiple lesions can help distinguish separate primary tumors from metastatic disease. PMID:27368115
The Effects of Oncologist Implicit Racial Bias in Racially Discordant Oncology Interactions.
Penner, Louis A; Dovidio, John F; Gonzalez, Richard; Albrecht, Terrance L; Chapman, Robert; Foster, Tanina; Harper, Felicity W K; Hagiwara, Nao; Hamel, Lauren M; Shields, Anthony F; Gadgeel, Shirish; Simon, Michael S; Griggs, Jennifer J; Eggly, Susan
2016-08-20
Health providers' implicit racial bias negatively affects communication and patient reactions to many medical interactions. However, its effects on racially discordant oncology interactions are largely unknown. Thus, we examined whether oncologist implicit racial bias has similar effects in oncology interactions. We further investigated whether oncologist implicit bias negatively affects patients' perceptions of recommended treatments (i.e., degree of confidence, expected difficulty). We predicted oncologist implicit bias would negatively affect communication, patient reactions to interactions, and, indirectly, patient perceptions of recommended treatments. Participants were 18 non-black medical oncologists and 112 black patients. Oncologists completed an implicit racial bias measure several weeks before video-recorded treatment discussions with new patients. Observers rated oncologist communication and recorded interaction length of time and amount of time oncologists and patients spoke. Following interactions, patients answered questions about oncologists' patient-centeredness and difficulty remembering contents of the interaction, distress, trust, and treatment perceptions. As predicted, oncologists higher in implicit racial bias had shorter interactions, and patients and observers rated these oncologists' communication as less patient-centered and supportive. Higher implicit bias also was associated with more patient difficulty remembering contents of the interaction. In addition, oncologist implicit bias indirectly predicted less patient confidence in recommended treatments, and greater perceived difficulty completing them, through its impact on oncologists' communication (as rated by both patients and observers). Oncologist implicit racial bias is negatively associated with oncologist communication, patients' reactions to racially discordant oncology interactions, and patient perceptions of recommended treatments. These perceptions could subsequently directly
Wu, Hongle; Zeng, Benhua; Li, Bolei; Ren, Biao; Zhao, Jianhua; Li, Mingyun; Peng, Xian; Feng, Mingye; Li, Jiyao; Wei, Hong; Cheng, Lei; Zhou, Xuedong
2018-05-08
Oral microbiome is potentially correlated with many diseases, such as dental caries, periodontitis, oral cancer and some systemic diseases. Twin model, as an effective method for studying human microbiota, is widely used in research of relationship between oral microbiota and dental caries. However, there were few researches focusing on caries discordant twins. In this study, in vitro assays were conducted combined with 16S rRNA sequencing analysis on oral microbiota sampled from twins who presented discordant caries experience and mice model was developed as well. Results showed that oral microbiota from caries-active twin possessed higher metabolic activity and produced more lactic production. 16S rRNA sequencing analysis showed that more than 80% of family taxa could be transferred into gnotobiotic-mice. Key caries-associated genera were significantly different between twins and the same difference in genus level could be found in mice as well (p < 0.05). This study suggested that oral microbiota of twins could be distinguished from each other despite the similarities in genetic make-up, living environment, and lifestyle. The difference in microbiota was applied to develop a mice model which may facilitate the investigation of core microbiota of dental caries.
Hulshoff Pol, Hilleke E; Brans, Rachel G H; van Haren, Neeltje E M; Schnack, Hugo G; Langen, Marieke; Baaré, Wim F C; van Oel, Clarine J; Kahn, René S
2004-01-15
Whole brain tissue volume decreases in schizophrenia have been related to both genetic risk factors and disease-related (possibly nongenetic) factors; however, whether genetic and environmental risk factors in the brains of patients with schizophrenia are differentially reflected in gray or white matter volume change is not known. Magnetic resonance imaging (1.5 T) brain scans of 11 monozygotic and 11 same-gender dizygotic twin pairs discordant for schizophrenia were acquired and compared with 11 monozygotic and 11 same-gender dizygotic healthy control twin pairs. Repeated-measures volume analysis of covariance revealed decreased whole brain volume in the patients with schizophrenia as compared with their co-twins and with healthy twin pairs. Decreased white matter volume was found in discordant twin pairs compared with healthy twin pairs, particularly in the monozygotic twin pairs. A decrease in gray matter was found in the patients compared with their co-twins and compared with the healthy twins. The results suggest that the decreases in white matter volume reflect the increased genetic risk to develop schizophrenia, whereas the decreases in gray matter volume are related to environmental risk factors. Study of genes involved in the (maintenance) of white matter structures may be particularly fruitful in schizophrenia.
Emusu, Donath; Ivankova, Nataliya; Jolly, Pauline; Kirby, Russell; Foushee, Herman; Wabwire-Mangen, Fred; Katongole, Drake; Ehiri, John
2009-01-01
HIV-serodiscordant relationships are those in which one partner is infected with HIV while the other is not. We investigated experiences of sexual violence among women in HIV discordant unions attending HIV post-test club services in Uganda. A volunteer sample of 26 women from three AIDS Information Centres in Uganda who reported having experienced sexual violence in a larger epidemiological study were interviewed, using the qualitative critical incident technique. Data were analysed using TEXTPACK, a software application for computer-assisted content analysis. Incidents of sexual violence narrated by the women included use of physical force and verbal threats. Overall, four themes that characterise the women’s experience of sexual violence emerged from the analysis: knowledge of HIV test results, prevalence of sexual violence, vulnerability and proprietary views and reactions to sexual violence. Alcohol abuse by the male partners was an important factor in the experience of sexual violence among the women. Their experiences evoked different reactions and feelings, including concern over the need to have children, fear of infection, desire to separate from their spouses/partners, helplessness, anger and suicidal tendencies. HIV counselling and testing centres should be supported with the capacity to address issues related to sexual violence for couples who are HIV discordant. PMID:20024712
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
Plasma cytokine profiling in sibling pairs discordant for autism spectrum disorder
2013-01-01
Objective Converging lines of evidence point to the existence of immune dysfunction in autism spectrum disorder (ASD), which could directly affect several key neurodevelopmental processes. Previous studies have shown higher cytokine levels in patients with autism compared with matched controls or subjects with other developmental disorders. In the current study, we used plasma-cytokine profiling for 25 discordant sibling pairs to evaluate whether these alterations occur within families with ASD. Methods Plasma-cytokine profiling was conducted using an array-based multiplex sandwich ELISA for simultaneous quantitative measurement of 40 unique targets. We also analyzed the correlations between cytokine levels and clinically relevant quantitative traits (Vineland Adaptive Behavior Scale in Autism (VABS) composite score, Social Responsiveness Scale (SRS) total T score, head circumference, and full intelligence quotient (IQ)). In addition, because of the high phenotypic heterogeneity of ASD, we defined four subgroups of subjects (those who were non-verbal, those with gastrointestinal issues, those with regressive autism, and those with a history of allergies), which encompass common and/or recurrent endophenotypes in ASD, and tested the cytokine levels in each group. Results None of the measured parameters showed significant differences between children with ASD and their related typically developing siblings. However, specific target levels did correlate with quantitative clinical traits, and these were significantly different when the ASD subgroups were analyzed. It is notable that these differences seem to be attributable to a predisposing immunogenetic background, as no other significant differences were noticed between discordant sibling pairs. Interleukin-1β appears to be the cytokine most involved in quantitative traits and clinical subgroups of ASD. Conclusions In the present study, we found a lack of significant differences in plasma-cytokine levels between
SI – SRH Sexual-risk factors of partner age-discordance in adolescent girls and their male partners
Morrison-Beedy, Dianne; Xia, Yinglin; Passmore, Denise
2013-01-01
Aim and objectives To investigate differences in sexual-risk factors between adolescent girls reporting similar-aged or older sex partners. Background Adolescent girls are at significant risk for heterosexual-acquired HIV infection and other long term reproductive health issues. Sexual partner age-discordance in teen girls has been correlated with STIs, lack of protection, multiple partners, and earlier age of sexual transition. Design A descriptive study comparing girls currently involved with age-discordant partners to those with similar-aged partners. Two-sample t-test for continuous variables and for categorical variables, Chi-square or Fisher exact test were used to compare groups. Methods Baseline data from 738 sexually-active, urban, adolescent girls ages 15 to 19, were analyzed to determine which behaviors were more likely to occur in girls with older partners. Data were collected as part of a gender specific HIV-prevention intervention in a randomized controlled trial tailored to adolescent girls. Results Multiple reported sexual risk behaviors were found to significantly differ between the two groups at baseline. Overall, girls with older partners had more episodes of sexual instances (vaginal, anal, and oral). Specific sexual risk behaviors were found to be statistically significant between the two groups. Girls with older partners started having sex at earlier ages, had more lifetime sexual partners, higher incidents of STIs and were reluctant to discuss using condoms with their partners. Girls with similar-aged partners were less willing to engage in risky sexual behaviors. Conclusions Findings from this investigation support data from other studies. Relationships with older male partners place adolescent girls at increased risk for HIV/STIs and unintended pregnancy. Relevance to clinical practice Adolescent girls in age-discordant relationships are at risk for immediate and long term sexual health morbidities. Identifying girls who are at increased
Quantum space and quantum completeness
NASA Astrophysics Data System (ADS)
Jurić, Tajron
2018-05-01
Motivated by the question whether quantum gravity can "smear out" the classical singularity we analyze a certain quantum space and its quantum-mechanical completeness. Classical singularity is understood as a geodesic incompleteness, while quantum completeness requires a unique unitary time evolution for test fields propagating on an underlying background. Here the crucial point is that quantum completeness renders the Hamiltonian (or spatial part of the wave operator) to be essentially self-adjoint in order to generate a unique time evolution. We examine a model of quantum space which consists of a noncommutative BTZ black hole probed by a test scalar field. We show that the quantum gravity (noncommutative) effect is to enlarge the domain of BTZ parameters for which the relevant wave operator is essentially self-adjoint. This means that the corresponding quantum space is quantum complete for a larger range of BTZ parameters rendering the conclusion that in the quantum space one observes the effect of "smearing out" the singularity.
USDA-ARS?s Scientific Manuscript database
Objective. This study uses a weight-discordant sibling design to examine the relationships between best friend’s body mass index z-score (zBMI) and siblings’ zBMI and obesity-related health behaviors (energy intake, consumption of sugar-sweetened beverages [SSB], physical activity and sedentary time...
Metataxonomic Analysis of Individuals at BMI Extremes and Monozygotic Twins Discordant for BMI.
Finnicum, Casey T; Doornweerd, Stieneke; Dolan, Conor V; Luningham, Justin M; Beck, Jeffrey J; Willemsen, Gonneke; Ehli, Erik A; Boomsma, Dorret I; Ijzerman, Richard G; Davies, Gareth E; de Geus, Eco J C
2018-06-01
The human gut microbiota has been demonstrated to be associated with a number of host phenotypes, including obesity and a number of obesity-associated phenotypes. This study is aimed at further understanding and describing the relationship between the gut microbiota and obesity-associated measurements obtained from human participants. Here, we utilize genetically informative study designs, including a four-corners design (extremes of genetic risk for BMI and of observed BMI; N = 50) and the BMI monozygotic (MZ) discordant twin pair design (N = 30), in order to help delineate the role of host genetics and the gut microbiota in the development of obesity. Our results highlight a negative association between BMI and alpha diversity of the gut microbiota. The low genetic risk/high BMI group of individuals had a lower gut microbiota alpha diversity when compared to the other three groups. Although the difference in alpha diversity between the lean and heavy groups of the BMI-discordant MZ twin design did not achieve significance, this difference was observed to be in the expected direction, with the heavier participants having a lower average alpha diversity. We have also identified nine OTUs observed to be associated with either a leaner or heavier phenotype, with enrichment for OTUs classified to the Ruminococcaceae and Oxalobacteraceae taxonomic families. Our study presents evidence of a relationship between BMI and alpha diversity of the gut microbiota. In addition to these findings, a number of OTUs were found to be significantly associated with host BMI. These findings may highlight separate subtypes of obesity, one driven by genetic factors, the other more heavily influenced by environmental factors.
Quantumness-generating capability of quantum dynamics
NASA Astrophysics Data System (ADS)
Li, Nan; Luo, Shunlong; Mao, Yuanyuan
2018-04-01
We study quantumness-generating capability of quantum dynamics, where quantumness refers to the noncommutativity between the initial state and the evolving state. In terms of the commutator of the square roots of the initial state and the evolving state, we define a measure to quantify the quantumness-generating capability of quantum dynamics with respect to initial states. Quantumness-generating capability is absent in classical dynamics and hence is a fundamental characteristic of quantum dynamics. For qubit systems, we present an analytical form for this measure, by virtue of which we analyze several prototypical dynamics such as unitary dynamics, phase damping dynamics, amplitude damping dynamics, and random unitary dynamics (Pauli channels). Necessary and sufficient conditions for the monotonicity of quantumness-generating capability are also identified. Finally, we compare these conditions for the monotonicity of quantumness-generating capability with those for various Markovianities and illustrate that quantumness-generating capability and quantum Markovianity are closely related, although they capture different aspects of quantum dynamics.
van ’t Ent, D.; van Beijsterveldt, C.E.M.; Derks, E.M.; Hudziak, J.J.; Veltman, D.J.; Todd, R.D.; Boomsma, D.I.; De Geus, E.J.C.
2009-01-01
Attention deficit hyperactivity disorder (ADHD) is to a large extent influenced by genetic factors, but environmental influences are considered important as well. To distinguish between functional brain changes underlying primarily genetically and environmentally mediated ADHD, we used functional MRI to compare response interference in monozygotic twins highly concordant or discordant for attention problems (AP). AP scores were assessed longitudinally with the Child Behavior Check List attention problem scale (CBCL-AP). Response interference was measured during two executive function paradigms; a color-word Stroop and a flanker task. The neuroimaging results indicated that, across the entire sample, children with high CBCL-AP scores, relative to children with low CBCL-AP scores, showed decreased activation to response interference in dorsolateral prefrontal, parietal and temporal brain regions. Increased activation was noted in the premotor cortex and regions associated with visual selective attention processing, possibly reflecting compensatory mechanisms to maintain task performance. Specific comparisons of high and low scoring concordant twin pairs suggest that AP of genetic origin was characterized by decreased activation of the left dorsolateral prefrontal cortex during the Stroop task and right parietal lobe during the flanker task. In contrast, comparison of twins from discordant monozygotic pairs, suggest that AP of environmental origin was characterized by decreased activation in left and right temporal lobe areas, but only during Stroop interference. The finding of distinct brain activation changes to response interference in inattention/hyperactivity of ‘genetic’ versus ‘environmental’ origin, indicate that genetic and environmental risk factors for attention/hyperactivity problems affect the brain in different ways. PMID:19409224
Duan, Song; Ding, Yingying; Yang, Yuecheng; Lu, Lin; Sun, Jiangping; Wang, Ning; Wang, Lu; Xiang, Lifen; Jia, Manhong; Wu, Zunyou; He, Na
2012-11-01
Many people from Burma have migrated to Dehong prefecture and married local residents during the past decades; however, little is known about HIV risk-taking behaviours and HIV prevalence among these mixed couples. We investigated factors correlated with HIV discordance and concordance within Chinese?Burmese mixed couples in Dehong prefecture, Yunnan province, China. A cross-sectional study with face-to-face questionnaire interviews and HIV blood testing was conducted. Of 5742 couples, 1.6% couples were HIV-infected concordant, 2.2% were HIV serodiscordant with an HIV-infected male spouse and 0.9% were HIV serodiscordant with an HIV-infected female spouse. HIV discordance with an HIV-infected male spouse was significantly associated with characteristics of the male spouse, including being aged =30 years, non-Han ethnic minority, a marital relationship of <3 years, commercial sex and injection drug use by the male spouse. HIV discordance with an HIV-infected female spouse was significantly associated with an education level of primary school (v. illiterate); a marital status of being in their second marriage, widowed or divorced; a history of sexually transmissible infection diagnosis of the female spouse; noncommercial extramarital sex by the female spouse or by both spouses; and injection drug use by the male spouse. A marital relationship of =3 years was the only significant independent correlate of HIV-infected seroconcordance. The study findings underscore the importance of premarital HIV counselling and testing for this population, and the need for targeted interventions among HIV serodiscordant mixed couples to reduce secondary transmission as early as possible when the relationship begins.
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 ensembles of quantum classifiers.
Schuld, Maria; Petruccione, Francesco
2018-02-09
Quantum machine learning witnesses an increasing amount of quantum algorithms for data-driven decision making, a problem with potential applications ranging from automated image recognition to medical diagnosis. Many of those algorithms are implementations of quantum classifiers, or models for the classification of data inputs with a quantum computer. Following the success of collective decision making with ensembles in classical machine learning, this paper introduces the concept of quantum ensembles of quantum classifiers. Creating the ensemble corresponds to a state preparation routine, after which the quantum classifiers are evaluated in parallel and their combined decision is accessed by a single-qubit measurement. This framework naturally allows for exponentially large ensembles in which - similar to Bayesian learning - the individual classifiers do not have to be trained. As an example, we analyse an exponentially large quantum ensemble in which each classifier is weighed according to its performance in classifying the training data, leading to new results for quantum as well as classical machine learning.
Quantum Foundations of Quantum Information
NASA Astrophysics Data System (ADS)
Griffiths, Robert
2009-03-01
The main foundational issue for quantum information is: What is quantum information about? What does it refer to? Classical information typically refers to physical properties, and since classical is a subset of quantum information (assuming the world is quantum mechanical), quantum information should--and, it will be argued, does--refer to quantum physical properties represented by projectors on appropriate subspaces of a quantum Hilbert space. All sorts of microscopic and macroscopic properties, not just measurement outcomes, can be represented in this way, and are thus a proper subject of quantum information. The Stern-Gerlach experiment illustrates this. When properties are compatible, which is to say their projectors commute, Shannon's classical information theory based on statistical correlations extends without difficulty or change to the quantum case. When projectors do not commute, giving rise to characteristic quantum effects, a foundation for the subject can still be constructed by replacing the ``measurement and wave-function collapse'' found in textbooks--an efficient calculational tool, but one giving rise to numerous conceptual difficulties--with a fully consistent and paradox free stochastic formulation of standard quantum mechanics. This formulation is particularly helpful in that it contains no nonlocal superluminal influences; the reason the latter carry no information is that they do not exist.
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
Jiao, Zhe; Jiang, Zhimei; Wang, Jingtao; Xu, Hui; Zhang, Qiang; Liu, Shuang; Du, Ning; Zhang, Yuanyuan; Qiu, Hongbin
2017-01-01
Cerebral palsy (CP) is a severe type of brain disease affecting movement and posture. Although CP has strong genetic and environmental components, considerable differences in the methylome between monozygotic (MZ) twins discordant for CP implicates epigenetic contributors as well. In order to determine the differences in methylation in patients with CP without interference of the interindividual genomic variation, four pairs of MZ twins discordant for CP were profiled for DNA methylation changes using reduced representation bisulfite sequencing on the genomic-scale. Similar DNA methylation patterns were observed in all samples. However, MZ twins demonstrated higher correlations and closer evolutionary associations compared with the other samples, indicating a stable methylome of MZ twins. A total of 190 differentially methylated genes (DMGs) were identified using Student's t-test, of which 37 genes were hypermethylated in the CP group while the remainders were hypomethylated compared with control group. The identified DMGs were enriched in several cerebral abnormalities, including cerebral cortical atrophy and cerebral atrophy, suggesting that the occurrence of CP may be associated with the methylation alterations. The neighboring genes of DMGs in the protein-protein interaction network were enriched in numerous important functions in essential processes. The results of the present study identified important genes that may epigenetically contribute to the occurrence and development of CP in MZ twins, suggesting that the different prevalence of CP in identical twins may be associated with DNA methylation alterations. PMID:29039597
2010-01-01
Background Follicle stimulating hormone (FSH) and anti-Müllerian hormone (AMH) represent the two most frequently utilized laboratory tests in determining ovarian reserve (OR). This study determined the clinical significance of their concordance and discordance in female infertility patients. Methods We investigated 366 consecutive infertility patients (350 reached IVF), excluding women with polycystic ovarian syndrome (PCOS). They were considered to have normal FSH and AMH if values fell within age-specific (as-) 95% confidence intervals (CI), and to suffer from diminished ovarian reserve (DOR) if FSH exceeded and/or AMH fell below those. The two hormones, thus, could be concordant (Group I), both normal (IA) or abnormal (IB), show normal AMH/abnormal FSH (Group II) or normal FSH/abnormal AMH (Group III). Oocyte yields, stratified for age categories, were then studied in each group as reflection of OR. Results Oocyte yields significantly decreased from groups IA to II to III and IB. Predictive values of as-FSH/AMH patterns changed, however, at different ages. Except at very young and very old ages, normal as-AMH better predicted higher oocytes yields than normal as-FSH, though above age 42 years normal as-FSH predicts good oocyte yields even with abnormally low AMH. Under age 42 discrepancies between as- FSH and as-AMH remain similarly predictive of oocyte yields at all ages. Discussion Concordances and discordances between as-FSH and as-AMH improve OR assessments and predictability of oocyte yields in IVF. PMID:20565808
Young, Paul E; Kum Jew, Stephen; Buckland, Michael E; Pamphlett, Roger; Suter, Catherine M
2017-01-01
Amyotrophic lateral sclerosis (ALS) is a devastating late-onset neurodegenerative disorder in which only a small proportion of patients carry an identifiable causative genetic lesion. Despite high heritability estimates, a genetic etiology for most sporadic ALS remains elusive. Here we report the epigenetic profiling of five monozygotic twin pairs discordant for ALS, four with classic ALS and one with the progressive muscular atrophy ALS variant, in whom previous whole genome sequencing failed to uncover a genetic basis for their disease discordance. By studying cytosine methylation patterns in peripheral blood DNA we identified thousands of large between-twin differences at individual CpGs. While the specific sites of differences were mostly idiosyncratic to a twin pair, a proportion involving GABA signalling were common to all ALS individuals. For both idiosyncratic and common sites the differences occurred within genes and pathways related to neurobiological functions or dysfunctions, some of particular relevance to ALS such as glutamate metabolism and the Golgi apparatus. All four classic ALS patients were epigenetically older than their unaffected co-twins, suggesting accelerated aging in multiple tissues in this disease. In conclusion, widespread changes in methylation patterns were found in ALS-affected co-twins, consistent with an epigenetic contribution to disease. These DNA methylation findings could be used to develop blood-based ALS biomarkers, gain insights into disease pathogenesis, and provide a reference for future large-scale ALS epigenetic studies.
Takahashi, Masahiro; Hosomichi, Kazuyoshi; Yamaguchi, Tetsutaro; Nagahama, Ryo; Yoshida, Hiroshi; Maki, Koutaro; Marazita, Mary L; Weinberg, Seth M; Tajima, Atsushi
2018-06-06
Orofacial clefts (OFCs) are common and aetiologically complex birth defects. This study explored potential genetic differences in a pair of Japanese monozygotic (MZ) twins with different forms of OFC using whole-genome sequencing. One co-twin (MZ-1) presented with non-syndromic bilateral cleft lip and palate; the other co-twin (MZ-2) had non-syndromic bilateral cleft lip and unilateral left-sided cleft alveolus. Neither parent had an OFC. Craniofacial morphologic features and potential genetic differences were compared using standard cephalometry and whole-genome sequencing, respectively. Morphologically, MZ-1 had a smaller vertical mandibular height, compared to MZ-2. However, no discordant genetic differences were detected. Moreover, both twins and their parents harboured rare candidate gene variants (GRHL3; TPM1) considered to be associated with OFCs. The observed differences between MZ-1 and MZ-2 in craniofacial morphology assessed by cephalograms might be directly attributable to the effects of the OFC on growth and/or differences in surgical history, given the lack of any differences in genetic background. However, comparisons of discordant MZ twins should continue to identify novel candidates that might control OFC or that might partly explain the missing heritability for this common birth defect, in addition to understanding craniofacial growth and development. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.
Heat flux and quantum correlations in dissipative cascaded systems
NASA Astrophysics Data System (ADS)
Lorenzo, Salvatore; Farace, Alessandro; Ciccarello, Francesco; Palma, G. Massimo; Giovannetti, Vittorio
2015-02-01
We study the dynamics of heat flux in the thermalization process of a pair of identical quantum systems that interact dissipatively with a reservoir in a cascaded fashion. Despite that the open dynamics of the bipartite system S is globally Lindbladian, one of the subsystems "sees" the reservoir in a state modified by the interaction with the other subsystem and hence it undergoes a non-Markovian dynamics. As a consequence, the heat flow exhibits a nonexponential time behavior which can greatly deviate from the case where each party is independently coupled to the reservoir. We investigate both thermal and correlated initial states of S and show that the presence of correlations at the beginning can considerably affect the heat-flux rate. We carry out our study in two paradigmatic cases—a pair of harmonic oscillators with a reservoir of bosonic modes and two qubits with a reservoir of fermionic modes—and compare the corresponding behaviors. In the case of qubits and for initial thermal states, we find that the trace distance discord is at any time interpretable as the correlated contribution to the total heat flux.
What is quantum in quantum randomness?
Grangier, P; Auffèves, A
2018-07-13
It is often said that quantum and classical randomness are of different nature, the former being ontological and the latter epistemological. However, so far the question of 'What is quantum in quantum randomness?', i.e. what is the impact of quantization and discreteness on the nature of randomness, remains to be answered. In a first part, we make explicit the differences between quantum and classical randomness within a recently proposed ontology for quantum mechanics based on contextual objectivity. In this view, quantum randomness is the result of contextuality and quantization. We show that this approach strongly impacts the purposes of quantum theory as well as its areas of application. In particular, it challenges current programmes inspired by classical reductionism, aiming at the emergence of the classical world from a large number of quantum systems. In a second part, we analyse quantum physics and thermodynamics as theories of randomness, unveiling their mutual influences. We finally consider new technological applications of quantum randomness that have opened up in the emerging field of quantum thermodynamics.This article is part of a discussion meeting issue 'Foundations of quantum mechanics and their impact on contemporary society'. © 2018 The Author(s).
Discordant introgression in a rapidly expanding hybrid swarm
Ward, Jessica L.; Blum, Mike J.; Walters, David M.; Porter, Brady A.; Burkhead, Noel; Freeman, Byron
2012-01-01
The erosion of species boundaries can involve rapid evolutionary change. Consequently, many aspects of the process remain poorly understood, including the formation, expansion, and evolution of hybrid swarms. Biological invasions involving hybridization present exceptional opportunities to study the erosion of species boundaries because timelines of interactions and outcomes are frequently well known. Here, we examined clinal variation across codominant and maternally inherited genetic markers as well as phenotypic traits to characterize the expansion and evolution of a hybrid swarm between native Cyprinella venusta and invasive Cyprinella lutrensis minnows. Discordant introgression of phenotype, microsatellite multilocus genotype, and mtDNA haplotype indicates that the observable expansion of the C. venusta x C. lutrensis hybrid swarm is a false invasion front. Both parental and hybrid individuals closely resembling C. lutrensis are numerically dominant in the expansion wake, indicating that the non-native parental phenotype may be selectively favored. These findings show that cryptic introgression can extend beyond the phenotypic boundaries of hybrid swarms and that hybrid swarms likely expand more rapidly than can be documented from phenotypic variation alone. Similarly, dominance of a single parental phenotype following an introduction event may lead to instances of species erosion being mistaken for species displacement without hybridization.
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…
Quantum Chess: Making Quantum Phenomena Accessible
NASA Astrophysics Data System (ADS)
Cantwell, Christopher
Quantum phenomena have remained largely inaccessible to the general public. There tends to be a scare factor associated with the word ``Quantum''. This is in large part due to the alien nature of phenomena such as superposition and entanglement. However, Quantum Computing is a very active area of research and one day we will have games that run on those quantum computers. Quantum phenomena such as superposition and entanglement will seem as normal as gravity. Is it possible to create such games today? Can we make games that are built on top of a realistic quantum simulation and introduce players of any background to quantum concepts in a fun and mentally stimulating way? One of the difficulties with any quantum simulation run on a classical computer is that the Hilbert space grows exponentially, making simulations of an appreciable size physically impossible due largely to memory restrictions. Here we will discuss the conception and development of Quantum Chess, and how to overcome some of the difficulties faced. We can then ask the question, ``What's next?'' What are some of the difficulties Quantum Chess still faces, and what is the future of quantum games?
Maternal feeding practices and fussy eating in toddlerhood: a discordant twin analysis.
Harris, Holly A; Fildes, Alison; Mallan, Kimberley M; Llewellyn, Clare H
2016-07-13
Parental feeding practices are thought to play a causal role in shaping a child's fussiness; however, a child-responsive model suggests that feeding practices may develop in response to a child's emerging appetitive characteristics. We used a novel twin study design to test the hypothesis that mothers vary their feeding practices for twin children who differ in their 'food fussiness', in support of a child-responsive model. Participants were mothers and their 16 month old twin children (n = 2026) from Gemini, a British twin birth cohort of children born in 2007. Standardized psychometric measures of maternal 'pressure to eat', 'restriction' and 'instrumental feeding', as well as child 'food fussiness', were completed by mothers. Within-family analyses examined if twin-pair differences in 'food fussiness' were associated with differences in feeding practices using linear regression models. In a subset of twins (n = 247 pairs) who were the most discordant (highest quartile) on 'food fussiness' (difference score ≥ .50), Paired Samples T-test were used to explore the magnitude of differences in feeding practices between twins. Between-family analyses used Complex Samples General Linear Models to examine associations between feeding practices and 'food fussiness'. Within-pair differences in 'food fussiness' were associated with differential 'pressure to eat' and 'instrumental feeding' (ps < .001), but not with 'restriction'. In the subset of twins most discordant on 'food fussiness', mothers used more pressure (p < .001) and food rewards (p < .05) with the fussier twin. Between-family analyses indicated that 'pressure to eat' and 'instrumental feeding' were positively associated with 'food fussiness', while 'restriction' was negatively associated with 'food fussiness' (ps < .001). Mothers appear to subtly adjust their feeding practices according to their perceptions of their toddler's emerging fussy eating behavior. Specifically, the
Expected number of quantum channels in quantum networks.
Chen, Xi; Wang, He-Ming; Ji, Dan-Tong; Mu, Liang-Zhu; Fan, Heng
2015-07-15
Quantum communication between nodes in quantum networks plays an important role in quantum information processing. Here, we proposed the use of the expected number of quantum channels as a measure of the efficiency of quantum communication for quantum networks. This measure quantified the amount of quantum information that can be teleported between nodes in a quantum network, which differs from classical case in that the quantum channels will be consumed if teleportation is performed. We further demonstrated that the expected number of quantum channels represents local correlations depicted by effective circles. Significantly, capacity of quantum communication of quantum networks quantified by ENQC is independent of distance for the communicating nodes, if the effective circles of communication nodes are not overlapped. The expected number of quantum channels can be enhanced through transformations of the lattice configurations of quantum networks via entanglement swapping. Our results can shed lights on the study of quantum communication in quantum networks.
Expected number of quantum channels in quantum networks
Chen, Xi; Wang, He-Ming; Ji, Dan-Tong; Mu, Liang-Zhu; Fan, Heng
2015-01-01
Quantum communication between nodes in quantum networks plays an important role in quantum information processing. Here, we proposed the use of the expected number of quantum channels as a measure of the efficiency of quantum communication for quantum networks. This measure quantified the amount of quantum information that can be teleported between nodes in a quantum network, which differs from classical case in that the quantum channels will be consumed if teleportation is performed. We further demonstrated that the expected number of quantum channels represents local correlations depicted by effective circles. Significantly, capacity of quantum communication of quantum networks quantified by ENQC is independent of distance for the communicating nodes, if the effective circles of communication nodes are not overlapped. The expected number of quantum channels can be enhanced through transformations of the lattice configurations of quantum networks via entanglement swapping. Our results can shed lights on the study of quantum communication in quantum networks. PMID:26173556
Blind Quantum Signature with Blind Quantum Computation
NASA Astrophysics Data System (ADS)
Li, Wei; Shi, Ronghua; Guo, Ying
2017-04-01
Blind quantum computation allows a client without quantum abilities to interact with a quantum server to perform a unconditional secure computing protocol, while protecting client's privacy. Motivated by confidentiality of blind quantum computation, a blind quantum signature scheme is designed with laconic structure. Different from the traditional signature schemes, the signing and verifying operations are performed through measurement-based quantum computation. Inputs of blind quantum computation are securely controlled with multi-qubit entangled states. The unique signature of the transmitted message is generated by the signer without leaking information in imperfect channels. Whereas, the receiver can verify the validity of the signature using the quantum matching algorithm. The security is guaranteed by entanglement of quantum system for blind quantum computation. It provides a potential practical application for e-commerce in the cloud computing and first-generation quantum computation.
Discordant mid-Cretaceous paleomagnetic pole from the Zaza Terrane of central Cuba
DOE Office of Scientific and Technical Information (OSTI.GOV)
Renne, P.R.; Doppelhammer, S.K.; Hargraves, R.B.
Thermal demagnetization of samples from five sites in mid-Cretaceous volcaniclastic and carbonate rocks of south-central Cuba reveals two or more components of magnetization. A pre-folding magnetite borne component is recognized in all, but was difficult to isolate from secondary components in many specimens. Remagnetization circle analysis, using data for 42 specimens from all five sites, yields a pole at 30.7{degree}N Lat., 193.3{degree}E Long. This pole is discordant with respect to the North American APWP, indicating 43{degree} {plus minus} 16{degree} of anticlockwise rotation and 8{degree} {plus minus} 6{degree} of northward displacement since the mid-Cretaceous. This result suggests that part or allmore » of Cuba was transported on the Caribbean plate before accretion to North America in the Eocene.« less
Two-qubit correlations via a periodic plasmonic nanostructure
NASA Astrophysics Data System (ADS)
Iliopoulos, Nikos; Terzis, Andreas F.; Yannopapas, Vassilios; Paspalakis, Emmanuel
2016-02-01
We theoretically investigate the generation of quantum correlations by using two distant qubits in free space or mediated by a plasmonic nanostructure. We report both entanglement of formation as well as quantum discord and classical correlations. We have found that for proper initial state of the two-qubit system and distance between the two qubits we can produce quantum correlations taking significant value for a relatively large time interval so that it can be useful in quantum information and computation processes.
Two-qubit correlations via a periodic plasmonic nanostructure
DOE Office of Scientific and Technical Information (OSTI.GOV)
Iliopoulos, Nikos; Terzis, Andreas F.; Yannopapas, Vassilios
2016-02-15
We theoretically investigate the generation of quantum correlations by using two distant qubits in free space or mediated by a plasmonic nanostructure. We report both entanglement of formation as well as quantum discord and classical correlations. We have found that for proper initial state of the two-qubit system and distance between the two qubits we can produce quantum correlations taking significant value for a relatively large time interval so that it can be useful in quantum information and computation processes.
NASA Technical Reports Server (NTRS)
Temple, D. R.; De Dios, Y. E.; Layne, C. S.; Bloomberg, J. J.; Mulavara, A. P.
2016-01-01
Astronauts exposed to microgravity face sensorimotor challenges incurred when readapting to a gravitational environment. Sensorimotor Adaptability (SA) training has been proposed as a countermeasure to improve locomotor performance during re-adaptation, and it is suggested that the benefits of SA training may be further enhanced by improving detection of weak sensory signals via mechanisms such as stochastic resonance when a non-zero level of stochastic white noise based electrical stimulation is applied to the vestibular system (stochastic vestibular stimulation, SVS). The purpose of this study was to test the efficacy of using SVS to improve short-term adaptation in a sensory discordant environment during performance of a locomotor task.
Gut microbiota from twins discordant for obesity modulate metabolism in mice.
Ridaura, Vanessa K; Faith, Jeremiah J; Rey, Federico E; Cheng, Jiye; Duncan, Alexis E; Kau, Andrew L; Griffin, Nicholas W; Lombard, Vincent; Henrissat, Bernard; Bain, James R; Muehlbauer, Michael J; Ilkayeva, Olga; Semenkovich, Clay F; Funai, Katsuhiko; Hayashi, David K; Lyle, Barbara J; Martini, Margaret C; Ursell, Luke K; Clemente, Jose C; Van Treuren, William; Walters, William A; Knight, Rob; Newgard, Christopher B; Heath, Andrew C; Gordon, Jeffrey I
2013-09-06
The role of specific gut microbes in shaping body composition remains unclear. We transplanted fecal microbiota from adult female twin pairs discordant for obesity into germ-free mice fed low-fat mouse chow, as well as diets representing different levels of saturated fat and fruit and vegetable consumption typical of the U.S. diet. Increased total body and fat mass, as well as obesity-associated metabolic phenotypes, were transmissible with uncultured fecal communities and with their corresponding fecal bacterial culture collections. Cohousing mice harboring an obese twin's microbiota (Ob) with mice containing the lean co-twin's microbiota (Ln) prevented the development of increased body mass and obesity-associated metabolic phenotypes in Ob cage mates. Rescue correlated with invasion of specific members of Bacteroidetes from the Ln microbiota into Ob microbiota and was diet-dependent. These findings reveal transmissible, rapid, and modifiable effects of diet-by-microbiota interactions.
Quantum machine learning for quantum anomaly detection
NASA Astrophysics Data System (ADS)
Liu, Nana; Rebentrost, Patrick
2018-04-01
Anomaly detection is used for identifying data that deviate from "normal" data patterns. Its usage on classical data finds diverse applications in many important areas such as finance, fraud detection, medical diagnoses, data cleaning, and surveillance. With the advent of quantum technologies, anomaly detection of quantum data, in the form of quantum states, may become an important component of quantum applications. Machine-learning algorithms are playing pivotal roles in anomaly detection using classical data. Two widely used algorithms are the kernel principal component analysis and the one-class support vector machine. We find corresponding quantum algorithms to detect anomalies in quantum states. We show that these two quantum algorithms can be performed using resources that are logarithmic in the dimensionality of quantum states. For pure quantum states, these resources can also be logarithmic in the number of quantum states used for training the machine-learning algorithm. This makes these algorithms potentially applicable to big quantum data applications.
Quantum Walk Schemes for Universal Quantum Computation
NASA Astrophysics Data System (ADS)
Underwood, Michael S.
Random walks are a powerful tool for the efficient implementation of algorithms in classical computation. Their quantum-mechanical analogues, called quantum walks, hold similar promise. Quantum walks provide a model of quantum computation that has recently been shown to be equivalent in power to the standard circuit model. As in the classical case, quantum walks take place on graphs and can undergo discrete or continuous evolution, though quantum evolution is unitary and therefore deterministic until a measurement is made. This thesis considers the usefulness of continuous-time quantum walks to quantum computation from the perspectives of both their fundamental power under various formulations, and their applicability in practical experiments. In one extant scheme, logical gates are effected by scattering processes. The results of an exhaustive search for single-qubit operations in this model are presented. It is shown that the number of distinct operations increases exponentially with the number of vertices in the scattering graph. A catalogue of all graphs on up to nine vertices that implement single-qubit unitaries at a specific set of momenta is included in an appendix. I develop a novel scheme for universal quantum computation called the discontinuous quantum walk, in which a continuous-time quantum walker takes discrete steps of evolution via perfect quantum state transfer through small 'widget' graphs. The discontinuous quantum-walk scheme requires an exponentially sized graph, as do prior discrete and continuous schemes. To eliminate the inefficient vertex resource requirement, a computation scheme based on multiple discontinuous walkers is presented. In this model, n interacting walkers inhabiting a graph with 2n vertices can implement an arbitrary quantum computation on an input of length n, an exponential savings over previous universal quantum walk schemes. This is the first quantum walk scheme that allows for the application of quantum error correction
Quantum information. Unconditional quantum teleportation between distant solid-state quantum bits.
Pfaff, W; Hensen, B J; Bernien, H; van Dam, S B; Blok, M S; Taminiau, T H; Tiggelman, M J; Schouten, R N; Markham, M; Twitchen, D J; Hanson, R
2014-08-01
Realizing robust quantum information transfer between long-lived qubit registers is a key challenge for quantum information science and technology. Here we demonstrate unconditional teleportation of arbitrary quantum states between diamond spin qubits separated by 3 meters. We prepare the teleporter through photon-mediated heralded entanglement between two distant electron spins and subsequently encode the source qubit in a single nuclear spin. By realizing a fully deterministic Bell-state measurement combined with real-time feed-forward, quantum teleportation is achieved upon each attempt with an average state fidelity exceeding the classical limit. These results establish diamond spin qubits as a prime candidate for the realization of quantum networks for quantum communication and network-based quantum computing. Copyright © 2014, American Association for the Advancement of Science.
Young, Paul E.; Kum Jew, Stephen; Buckland, Michael E.; Pamphlett, Roger
2017-01-01
Amyotrophic lateral sclerosis (ALS) is a devastating late-onset neurodegenerative disorder in which only a small proportion of patients carry an identifiable causative genetic lesion. Despite high heritability estimates, a genetic etiology for most sporadic ALS remains elusive. Here we report the epigenetic profiling of five monozygotic twin pairs discordant for ALS, four with classic ALS and one with the progressive muscular atrophy ALS variant, in whom previous whole genome sequencing failed to uncover a genetic basis for their disease discordance. By studying cytosine methylation patterns in peripheral blood DNA we identified thousands of large between-twin differences at individual CpGs. While the specific sites of differences were mostly idiosyncratic to a twin pair, a proportion involving GABA signalling were common to all ALS individuals. For both idiosyncratic and common sites the differences occurred within genes and pathways related to neurobiological functions or dysfunctions, some of particular relevance to ALS such as glutamate metabolism and the Golgi apparatus. All four classic ALS patients were epigenetically older than their unaffected co-twins, suggesting accelerated aging in multiple tissues in this disease. In conclusion, widespread changes in methylation patterns were found in ALS-affected co-twins, consistent with an epigenetic contribution to disease. These DNA methylation findings could be used to develop blood-based ALS biomarkers, gain insights into disease pathogenesis, and provide a reference for future large-scale ALS epigenetic studies. PMID:28797086
Parametric Quantum Search Algorithm as Quantum Walk: A Quantum Simulation
NASA Astrophysics Data System (ADS)
Ellinas, Demosthenes; Konstandakis, Christos
2016-02-01
Parametric quantum search algorithm (PQSA) is a form of quantum search that results by relaxing the unitarity of the original algorithm. PQSA can naturally be cast in the form of quantum walk, by means of the formalism of oracle algebra. This is due to the fact that the completely positive trace preserving search map used by PQSA, admits a unitarization (unitary dilation) a la quantum walk, at the expense of introducing auxiliary quantum coin-qubit space. The ensuing QW describes a process of spiral motion, chosen to be driven by two unitary Kraus generators, generating planar rotations of Bloch vector around an axis. The quadratic acceleration of quantum search translates into an equivalent quadratic saving of the number of coin qubits in the QW analogue. The associated to QW model Hamiltonian operator is obtained and is shown to represent a multi-particle long-range interacting quantum system that simulates parametric search. Finally, the relation of PQSA-QW simulator to the QW search algorithm is elucidated.
Quantum demultiplexer of quantum parameter-estimation information in quantum networks
NASA Astrophysics Data System (ADS)
Xie, Yanqing; Huang, Yumeng; Wu, Yinzhong; Hao, Xiang
2018-05-01
The quantum demultiplexer is constructed by a series of unitary operators and multipartite entangled states. It is used to realize information broadcasting from an input node to multiple output nodes in quantum networks. The scheme of quantum network communication with respect to phase estimation is put forward through the demultiplexer subjected to amplitude damping noises. The generalized partial measurements can be applied to protect the transferring efficiency from environmental noises in the protocol. It is found out that there are some optimal coherent states which can be prepared to enhance the transmission of phase estimation. The dynamics of state fidelity and quantum Fisher information are investigated to evaluate the feasibility of the network communication. While the state fidelity deteriorates rapidly, the quantum Fisher information can be enhanced to a maximum value and then decreases slowly. The memory effect of the environment induces the oscillations of fidelity and quantum Fisher information. The adjustment of the strength of partial measurements is helpful to increase quantum Fisher information.
Research progress on quantum informatics and quantum computation
NASA Astrophysics Data System (ADS)
Zhao, Yusheng
2018-03-01
Quantum informatics is an emerging interdisciplinary subject developed by the combination of quantum mechanics, information science, and computer science in the 1980s. The birth and development of quantum information science has far-reaching significance in science and technology. At present, the application of quantum information technology has become the direction of people’s efforts. The preparation, storage, purification and regulation, transmission, quantum coding and decoding of quantum state have become the hotspot of scientists and technicians, which have a profound impact on the national economy and the people’s livelihood, technology and defense technology. This paper first summarizes the background of quantum information science and quantum computer and the current situation of domestic and foreign research, and then introduces the basic knowledge and basic concepts of quantum computing. Finally, several quantum algorithms are introduced in detail, including Quantum Fourier transform, Deutsch-Jozsa algorithm, Shor’s quantum algorithm, quantum phase estimation.
Quantum probability and quantum decision-making.
Yukalov, V I; Sornette, D
2016-01-13
A rigorous general definition of quantum probability is given, which is valid not only for elementary events but also for composite events, for operationally testable measurements as well as for inconclusive measurements, and also for non-commuting observables in addition to commutative observables. Our proposed definition of quantum probability makes it possible to describe quantum measurements and quantum decision-making on the same common mathematical footing. Conditions are formulated for the case when quantum decision theory reduces to its classical counterpart and for the situation where the use of quantum decision theory is necessary. © 2015 The Author(s).
Fermionic entanglement via quantum walks in quantum dots
NASA Astrophysics Data System (ADS)
Melnikov, Alexey A.; Fedichkin, Leonid E.
2018-02-01
Quantum walks are fundamentally different from random walks due to the quantum superposition property of quantum objects. Quantum walk process was found to be very useful for quantum information and quantum computation applications. In this paper we demonstrate how to use quantum walks as a tool to generate high-dimensional two-particle fermionic entanglement. The generated entanglement can survive longer in the presence of depolorazing noise due to the periodicity of quantum walk dynamics. The possibility to create two distinguishable qudits in a system of tunnel-coupled semiconductor quantum dots is discussed.
Efficient quantum walk on a quantum processor
Qiang, Xiaogang; Loke, Thomas; Montanaro, Ashley; Aungskunsiri, Kanin; Zhou, Xiaoqi; O'Brien, Jeremy L.; Wang, Jingbo B.; Matthews, Jonathan C. F.
2016-01-01
The random walk formalism is used across a wide range of applications, from modelling share prices to predicting population genetics. Likewise, quantum walks have shown much potential as a framework for developing new quantum algorithms. Here we present explicit efficient quantum circuits for implementing continuous-time quantum walks on the circulant class of graphs. These circuits allow us to sample from the output probability distributions of quantum walks on circulant graphs efficiently. We also show that solving the same sampling problem for arbitrary circulant quantum circuits is intractable for a classical computer, assuming conjectures from computational complexity theory. This is a new link between continuous-time quantum walks and computational complexity theory and it indicates a family of tasks that could ultimately demonstrate quantum supremacy over classical computers. As a proof of principle, we experimentally implement the proposed quantum circuit on an example circulant graph using a two-qubit photonics quantum processor. PMID:27146471
Emergent mechanics, quantum and un-quantum
NASA Astrophysics Data System (ADS)
Ralston, John P.
2013-10-01
There is great interest in quantum mechanics as an "emergent" phenomenon. The program holds that nonobvious patterns and laws can emerge from complicated physical systems operating by more fundamental rules. We find a new approach where quantum mechanics itself should be viewed as an information management tool not derived from physics nor depending on physics. The main accomplishment of quantum-style theory comes in expanding the notion of probability. We construct a map from macroscopic information as data" to quantum probability. The map allows a hidden variable description for quantum states, and efficient use of the helpful tools of quantum mechanics in unlimited circumstances. Quantum dynamics via the time-dependent Shroedinger equation or operator methods actually represents a restricted class of classical Hamiltonian or Lagrangian dynamics, albeit with different numbers of degrees of freedom. We show that under wide circumstances such dynamics emerges from structureless dynamical systems. The uses of the quantum information management tools are illustrated by numerical experiments and practical applications
Experimental quantum forgery of quantum optical money
NASA Astrophysics Data System (ADS)
Bartkiewicz, Karol; Černoch, Antonín; Chimczak, Grzegorz; Lemr, Karel; Miranowicz, Adam; Nori, Franco
2017-03-01
Unknown quantum information cannot be perfectly copied (cloned). This statement is the bedrock of quantum technologies and quantum cryptography, including the seminal scheme of Wiesner's quantum money, which was the first quantum-cryptographic proposal. Surprisingly, to our knowledge, quantum money has not been tested experimentally yet. Here, we experimentally revisit the Wiesner idea, assuming a banknote to be an image encoded in the polarization states of single photons. We demonstrate that it is possible to use quantum states to prepare a banknote that cannot be ideally copied without making the owner aware of only unauthorized actions. We provide the security conditions for quantum money by investigating the physically-achievable limits on the fidelity of 1-to-2 copying of arbitrary sequences of qubits. These results can be applied as a security measure in quantum digital right management.
Dhanasekaran, S; Jenum, S; Stavrum, R; Ritz, C; Kenneth, J; Vaz, M; Doherty, T M; Grewal, H M S
2014-01-01
The tuberculin skin test (TST) and QuantiFERON-TB-Gold-In-tube (QFTGIT) are adjunctive tests used in the diagnosis of pediatric tuberculosis (TB). Neither test can rule out TB; however, a positive test usually triggers preventive treatment in TB contacts aged <5 years. TST and QFTGIT can give divergent results and it is unclear how discordant results should be interpreted in terms of TB risk and preventive treatment. To understand the immune processes underlying concordant or discordant TST and QFTGIT results, we analyzed immune responses in children from Palamaner Taluk in India (a TB-endemic region with routine neonatal BCG vaccination) who were referred to a TB case verification ward on suspicion of TB. Two hundred and ten children aged <3 years were classified according to their TST and QFTGIT results, and their immune responses analyzed by dual-colour-Reverse-Transcriptase-Multiple-Ligation-dependent-Probe-Amplification, using a panel of 45 genes and a 10-plex antigen-specific enzyme-linked immunosorbent assay. We show that immune biomarkers FPR1, TNFRSF1A and interferon (IFN)-γ are upregulated (all P<0.05) in concordant test-positive children, whereas BPI is downregulated (P<0.05). In contrast, SEC14L1 (P=0.034) and Interferon gamma-induced protein 10 (IP-10) (P=0.001) are differentially expressed between the TST+QFTGIT- /TST-QFTGIT+ groups. Known TB exposure was more frequent in concordant positive children and results were consistent with elevated expression of genes associated with inflammatory responses. Children with discordant test results displayed a mixed profile with activation of both pro- and anti-inflammatory markers. TST and/or QFTGIT positivity appears to reflect distinct but overlapping aspects of host immunity.
Zafer, Maryam; Horvath, Hacsi; Mmeje, Okeoma; van der Poel, Sheryl; Semprini, Augusto; Rutherford, George; Brown, Joelle
2015-01-01
Objective To evaluate the effectiveness of semen washing in HIV-discordant couples in which the male partner is infected Design Systematic review and meta-analysis Setting All countries Patient(s) Forty single-arm, open label studies among HIV-discordant couples that underwent intrauterine insemination (IUI) or in vitro fertilization (IVF) with or without intracytoplasmic sperm injection (ICSI) using washed semen Intervention(s) Semen washing followed by IUI, IVF, or IVF/ICSI Main outcome measure(s) Primary outcome: HIV transmission to HIV-uninfected women; secondary outcomes: HIV transmission to newborns and proportion of couples achieving a clinical pregnancy Result(s) No HIV transmission occurred in 11,585 cycles of assisted reproduction using washed semen among 3,994 women (95% confidence interval [CI] = 0–0.0001). Among the subset of HIV-infected men without plasma viral suppression at the time of semen washing, no HIV seroconversions occurred among 1,023 women following 2,863 cycles of assisted reproduction using washed semen (95%CI= 0–0.0006). Studies that measured HIV transmission to infants reported no cases of vertical transmission (0/1,026, 95% CI= 0–0.0029). Overall, 56.3% (2,357/4,184, 95%CI=54.8%–57.8%) of couples achieved a clinical pregnancy using washed semen. Conclusion(s) Semen washing appears to significantly reduce the risk of transmission in HIV-discordant couples desiring children, regardless of viral suppression in the male partner. There are no randomized, controlled studies or studies from low-income countries, especially those with a large burden of HIV. Continued development of lower-cost semen washing and assisted reproduction technologies is needed. Integration of semen washing into HIV prevention interventions could help further reduce the spread of HIV. PMID:26688556
Quantum thermodynamic cycles and quantum heat engines. II.
Quan, H T
2009-04-01
We study the quantum-mechanical generalization of force or pressure, and then we extend the classical thermodynamic isobaric process to quantum-mechanical systems. Based on these efforts, we are able to study the quantum version of thermodynamic cycles that consist of quantum isobaric processes, such as the quantum Brayton cycle and quantum Diesel cycle. We also consider the implementation of the quantum Brayton cycle and quantum Diesel cycle with some model systems, such as single particle in a one-dimensional box and single-mode radiation field in a cavity. These studies lay the microscopic (quantum-mechanical) foundation for Szilard-Zurek single-molecule engine.
Yang, Cui; Latkin, Carl; Tobin, Karin; Seal, David; Koblin, Beryl; Chander, Geetanjali; Siconolfi, Daniel; Flores, Stephen; Spikes, Pilgrim
2018-05-19
Despite the high HIV incidence and prevalence among black men who have sex with men (BMSM), little research has examined partner characteristics, partner seeking venue, sexual position, substance use, and sexual risk behavior at the sex event-level among BMSM. Using the baseline data from a multi-site study of 807 BMSM stratified by their HIV status, the goal of this study was to conduct a detailed event-level analysis of 1577 male anal sex events to assess the factors associated with condomless anal intercourse (CLAI) with a HIV-discordant or HIV status-unknown partner. We found CLAI with an HIV-discordant or unknown HIV status partner among HIV-negative BMSM was negatively associated with having sex with a main partner, and was positively associated with taking both receptive and insertive sexual positions during sex. As compared to a sex partner met at bar, night club or dance club, HIV-positive BMSM were less likely to engage in CLAI with HIV-discordant and unknown HIV status partner met at party or friend's house or at community organizations. HIV-positive BMSM had lower odds of engaging in CLAI with HIV-discordant and unknown HIV status partner if they had insertive sexual position or both receptive and insertive sexual positions. These results underscore the importance of delineating unique sex event-level factors associated with sexual risk behavior depending on individuals' HIV status. Our findings suggest event-level partner characteristics, sexual position, and partner seeking venues may contribute to disparities in HIV incidence.
The Quantum Steganography Protocol via Quantum Noisy Channels
NASA Astrophysics Data System (ADS)
Wei, Zhan-Hong; Chen, Xiu-Bo; Niu, Xin-Xin; Yang, Yi-Xian
2015-08-01
As a promising branch of quantum information hiding, Quantum steganography aims to transmit secret messages covertly in public quantum channels. But due to environment noise and decoherence, quantum states easily decay and change. Therefore, it is very meaningful to make a quantum information hiding protocol apply to quantum noisy channels. In this paper, we make the further research on a quantum steganography protocol for quantum noisy channels. The paper proved that the protocol can apply to transmit secret message covertly in quantum noisy channels, and explicity showed quantum steganography protocol. In the protocol, without publishing the cover data, legal receivers can extract the secret message with a certain probability, which make the protocol have a good secrecy. Moreover, our protocol owns the independent security, and can be used in general quantum communications. The communication, which happen in our protocol, do not need entangled states, so our protocol can be used without the limitation of entanglement resource. More importantly, the protocol apply to quantum noisy channels, and can be used widely in the future quantum communication.
Fictitious spin-12 operators and correlations in quadrupole nuclear spin system
NASA Astrophysics Data System (ADS)
Furman, G. B.; Goren, S. D.; Meerovich, V. M.; Sokolovsky, V. L.
The Hamiltonian and the spin operators for a spin 3/2 are represented in the basis formed by the Kronecker productions of the 2×2 Pauli matrices. This reformulation allows us to represent a spin 3/2 as a system of two coupled fictitious spins 1/2. Correlations between these fictitious spins are studied using well-developed methods. We investigate the temperature and field dependences of correlations, such as mutual information, classical correlations, entanglement, and geometric and quantum discords in the fictitious spin-1/2 system describing a nuclear spin 3/2 which is placed in magnetic and inhomogeneous electric fields. It is shown that the correlations between the fictitious spins demonstrate properties which differ from those of real two-spin systems. In contrast to real systems all the correlations between the fictitious spins do not vanish with increasing external magnetic field; at a high magnetic field the correlations tend to their limiting values. Classical correlations, quantum and geometric discords reveal a pronounced asymmetry relative to the measurements on subsystems (fictitious spins) even in a uniform magnetic field and at symmetrical EFG, η=0. The correlations depend also on the distribution of external charges, on the parameter of symmetry η. At η≠0 quantum and geometric discords have finite values in a zero magnetic field. The proposed approach may be useful in analysis of properties of particles with larger angular momentum, can provide the way to discover new physical phenomenon of quantum correlations, and can be a useful tool for similar definitions of other physical quantities of complex systems.
Quantum random oracle model for quantum digital signature
NASA Astrophysics Data System (ADS)
Shang, Tao; Lei, Qi; Liu, Jianwei
2016-10-01
The goal of this work is to provide a general security analysis tool, namely, the quantum random oracle (QRO), for facilitating the security analysis of quantum cryptographic protocols, especially protocols based on quantum one-way function. QRO is used to model quantum one-way function and different queries to QRO are used to model quantum attacks. A typical application of quantum one-way function is the quantum digital signature, whose progress has been hampered by the slow pace of the experimental realization. Alternatively, we use the QRO model to analyze the provable security of a quantum digital signature scheme and elaborate the analysis procedure. The QRO model differs from the prior quantum-accessible random oracle in that it can output quantum states as public keys and give responses to different queries. This tool can be a test bed for the cryptanalysis of more quantum cryptographic protocols based on the quantum one-way function.
Heritability of changes in brain volume over time in twin pairs discordant for schizophrenia.
Brans, Rachel G H; van Haren, Neeltje E M; van Baal, G Caroline M; Schnack, Hugo G; Kahn, René S; Hulshoff Pol, Hilleke E
2008-11-01
Structural brain abnormalities have consistently been found in schizophrenia, with increased familial risk for the disease associated with these abnormalities. Some brain volume changes are progressive over the course of the illness. Whether these progressive brain volume changes are mediated by genetic or disease-related factors is unknown. To investigate whether genetic and/or environmental factors are associated with progressive brain volume changes in schizophrenia. Longitudinal 5-year follow-up in monozygotic (MZ) and dizygotic (DZ) twin pairs discordant for schizophrenia and healthy comparison twin pairs using brain magnetic resonance imaging. Participants were recruited from the twin pair cohort at the University Medical Center Utrecht. A total of 92 participants completed the study: 9 MZ and 10 DZ twin pairs discordant for schizophrenia and 14 MZ and 13 DZ healthy twin pairs. Percentage volume changes of the whole brain; cerebral gray and white matter of the frontal, temporal, parietal, and occipital lobes; cerebellum; and lateral and third ventricles over time between and within twin pairs were compared using repeated measures analysis of covariance. Structural equation modeling was applied to estimate contributions of additive genetic and common and unique environmental factors. Significant decreases over time in whole brain and frontal and temporal lobe volumes were found in patients with schizophrenia and their unaffected co-twins compared with control twins. Bivariate structural equation modeling using cross-trait/cross-twin correlations revealed significant additive genetic influences on the correlations between schizophrenia liability and progressive whole brain (66%; 95% confidence interval [CI], 51%-100%), frontal lobe (76%; 95% CI, 54%-100%), and temporal lobe (79%; CI, 56%-100%) volume change. The progressive brain volume loss found in patients with schizophrenia and their unaffected co-twins is at least partly attributable to genetic factors
Lucenteforte, Ersilia; Moja, Lorenzo; Pecoraro, Valentina; Conti, Andrea A; Conti, Antonio; Crudeli, Elena; Galli, Alessio; Gensini, Gian Franco; Minnelli, Martina; Mugelli, Alessandro; Proietti, Riccardo; Shtylla, Jonida; D'Amico, Roberto; Parmelli, Elena; Virgili, Gianni
2015-03-01
To clarify the impact of multiple (covering the same population, intervention, control, and outcomes) systematic reviews (SRs) on interventions for myocardial infarction (MI). Clinical Evidence (BMJ Group) sections and related search strategies regarding MI were used to identify multiple SRs published between 1997 and 2007. Multiple SRs were classified as discordant if they featured conflicting results or interpretation of them. Thirty-six SRs (23.5% of 153 on the treatment or prevention of MI) were classified as multiple and grouped in 16 clusters [ie, at least two SRs with the same PICO (population, condition/disease, intervention, control) and at least one common outcome] exploring angioplasty, angiotensin-converting enzyme inhibitors, anticoagulants, antiplatelets, β-blockers, and stents. Complete agreement on statistically significant differences between interventions was found in 7 of 10 clusters with a shared composite outcome. Agreement was reduced when single outcomes were considered. Despite substantial variation and limited agreement in reporting of major outcomes, SRs agreed in their conclusions on the superiority of either the intervention or control in 14 of 16 clusters. Sources of minor discrepancies were found in terms of study and outcome selection, subgroup analyses, and interpretation of findings. Multiple SRs agreed in their qualitative conclusions but not on reporting and on analyses of hard outcomes. Discordance on significance of treatment effects was due to a combination of variation in design with inclusion of different studies and lack of precision for single hard outcomes compared with a composite outcome. Such inconsistencies among SRs could potentially slow the translation of SRs' results to clinical and public health decision making and suggest the need for a broader methodological and clinical agreement on their design. Copyright © 2015 Elsevier Inc. All rights reserved.
Quantum technology past, present, future: quantum energetics (Conference Presentation)
NASA Astrophysics Data System (ADS)
Choi, Sang H.
2017-04-01
Since the development of quantum physics in the early part of the 1900s, this field of study has made remarkable contributions to our civilization. Some of these advances include lasers, light-emitting diodes (LED), sensors, spectroscopy, quantum dots, quantum gravity and quantum entanglements. In 1998, the NASA Langley Research Center established a quantum technology committee to monitor the progress in this area and initiated research to determine the potential of quantum technology for future NASA missions. The areas of interest in quantum technology at NASA included fundamental quantum-optics materials associated with quantum dots and quantum wells, device-oriented photonic crystals, smart optics, quantum conductors, quantum information and computing, teleportation theorem, and quantum energetics. A brief review of the work performed, the progress made in advancing these technologies, and the potential NASA applications of quantum technology will be presented.
Quantum teleportation between remote atomic-ensemble quantum memories
Bao, Xiao-Hui; Xu, Xiao-Fan; Li, Che-Ming; Yuan, Zhen-Sheng; Lu, Chao-Yang; Pan, Jian-Wei
2012-01-01
Quantum teleportation and quantum memory are two crucial elements for large-scale quantum networks. With the help of prior distributed entanglement as a “quantum channel,” quantum teleportation provides an intriguing means to faithfully transfer quantum states among distant locations without actual transmission of the physical carriers [Bennett CH, et al. (1993) Phys Rev Lett 70(13):1895–1899]. Quantum memory enables controlled storage and retrieval of fast-flying photonic quantum bits with stationary matter systems, which is essential to achieve the scalability required for large-scale quantum networks. Combining these two capabilities, here we realize quantum teleportation between two remote atomic-ensemble quantum memory nodes, each composed of ∼108 rubidium atoms and connected by a 150-m optical fiber. The spin wave state of one atomic ensemble is mapped to a propagating photon and subjected to Bell state measurements with another single photon that is entangled with the spin wave state of the other ensemble. Two-photon detection events herald the success of teleportation with an average fidelity of 88(7)%. Besides its fundamental interest as a teleportation between two remote macroscopic objects, our technique may be useful for quantum information transfer between different nodes in quantum networks and distributed quantum computing. PMID:23144222
Quantum teleportation between remote atomic-ensemble quantum memories.
Bao, Xiao-Hui; Xu, Xiao-Fan; Li, Che-Ming; Yuan, Zhen-Sheng; Lu, Chao-Yang; Pan, Jian-Wei
2012-12-11
Quantum teleportation and quantum memory are two crucial elements for large-scale quantum networks. With the help of prior distributed entanglement as a "quantum channel," quantum teleportation provides an intriguing means to faithfully transfer quantum states among distant locations without actual transmission of the physical carriers [Bennett CH, et al. (1993) Phys Rev Lett 70(13):1895-1899]. Quantum memory enables controlled storage and retrieval of fast-flying photonic quantum bits with stationary matter systems, which is essential to achieve the scalability required for large-scale quantum networks. Combining these two capabilities, here we realize quantum teleportation between two remote atomic-ensemble quantum memory nodes, each composed of ∼10(8) rubidium atoms and connected by a 150-m optical fiber. The spin wave state of one atomic ensemble is mapped to a propagating photon and subjected to Bell state measurements with another single photon that is entangled with the spin wave state of the other ensemble. Two-photon detection events herald the success of teleportation with an average fidelity of 88(7)%. Besides its fundamental interest as a teleportation between two remote macroscopic objects, our technique may be useful for quantum information transfer between different nodes in quantum networks and distributed quantum computing.
Aggregating quantum repeaters for the quantum internet
NASA Astrophysics Data System (ADS)
Azuma, Koji; Kato, Go
2017-09-01
The quantum internet holds promise for accomplishing quantum teleportation and unconditionally secure communication freely between arbitrary clients all over the globe, as well as the simulation of quantum many-body systems. For such a quantum internet protocol, a general fundamental upper bound on the obtainable entanglement or secret key has been derived [K. Azuma, A. Mizutani, and H.-K. Lo, Nat. Commun. 7, 13523 (2016), 10.1038/ncomms13523]. Here we consider its converse problem. In particular, we present a universal protocol constructible from any given quantum network, which is based on running quantum repeater schemes in parallel over the network. For arbitrary lossy optical channel networks, our protocol has no scaling gap with the upper bound, even based on existing quantum repeater schemes. In an asymptotic limit, our protocol works as an optimal entanglement or secret-key distribution over any quantum network composed of practical channels such as erasure channels, dephasing channels, bosonic quantum amplifier channels, and lossy optical channels.
Quantum Secure Direct Communication with Quantum Memory
NASA Astrophysics Data System (ADS)
Zhang, Wei; Ding, Dong-Sheng; Sheng, Yu-Bo; Zhou, Lan; Shi, Bao-Sen; Guo, Guang-Can
2017-06-01
Quantum communication provides an absolute security advantage, and it has been widely developed over the past 30 years. As an important branch of quantum communication, quantum secure direct communication (QSDC) promotes high security and instantaneousness in communication through directly transmitting messages over a quantum channel. The full implementation of a quantum protocol always requires the ability to control the transfer of a message effectively in the time domain; thus, it is essential to combine QSDC with quantum memory to accomplish the communication task. In this Letter, we report the experimental demonstration of QSDC with state-of-the-art atomic quantum memory for the first time in principle. We use the polarization degrees of freedom of photons as the information carrier, and the fidelity of entanglement decoding is verified as approximately 90%. Our work completes a fundamental step toward practical QSDC and demonstrates a potential application for long-distance quantum communication in a quantum network.
Quantifying quantum coherence with quantum Fisher information.
Feng, X N; Wei, L F
2017-11-14
Quantum coherence is one of the old but always important concepts in quantum mechanics, and now it has been regarded as a necessary resource for quantum information processing and quantum metrology. However, the question of how to quantify the quantum coherence has just been paid the attention recently (see, e.g., Baumgratz et al. PRL, 113. 140401 (2014)). In this paper we verify that the well-known quantum Fisher information (QFI) can be utilized to quantify the quantum coherence, as it satisfies the monotonicity under the typical incoherent operations and the convexity under the mixing of the quantum states. Differing from most of the pure axiomatic methods, quantifying quantum coherence by QFI could be experimentally testable, as the bound of the QFI is practically measurable. The validity of our proposal is specifically demonstrated with the typical phase-damping and depolarizing evolution processes of a generic single-qubit state, and also by comparing it with the other quantifying methods proposed previously.
Quantum Secure Direct Communication with Quantum Memory.
Zhang, Wei; Ding, Dong-Sheng; Sheng, Yu-Bo; Zhou, Lan; Shi, Bao-Sen; Guo, Guang-Can
2017-06-02
Quantum communication provides an absolute security advantage, and it has been widely developed over the past 30 years. As an important branch of quantum communication, quantum secure direct communication (QSDC) promotes high security and instantaneousness in communication through directly transmitting messages over a quantum channel. The full implementation of a quantum protocol always requires the ability to control the transfer of a message effectively in the time domain; thus, it is essential to combine QSDC with quantum memory to accomplish the communication task. In this Letter, we report the experimental demonstration of QSDC with state-of-the-art atomic quantum memory for the first time in principle. We use the polarization degrees of freedom of photons as the information carrier, and the fidelity of entanglement decoding is verified as approximately 90%. Our work completes a fundamental step toward practical QSDC and demonstrates a potential application for long-distance quantum communication in a quantum network.
Quantum capacity of quantum black holes
NASA Astrophysics Data System (ADS)
Adami, Chris; Bradler, Kamil
2014-03-01
The fate of quantum entanglement interacting with a black hole has been an enduring mystery, not the least because standard curved space field theory does not address the interaction of black holes with matter. We discuss an effective Hamiltonian of matter interacting with a black hole that has a precise analogue in quantum optics and correctly reproduces both spontaneous and stimulated Hawking radiation with grey-body factors. We calculate the quantum capacity of this channel in the limit of perfect absorption, as well as in the limit of a perfectly reflecting black hole (a white hole). We find that the white hole is an optimal quantum cloner, and is isomorphic to the Unruh channel with positive quantum capacity. The complementary channel (across the horizon) is entanglement-breaking with zero capacity, avoiding a violation of the quantum no-cloning theorem. The black hole channel on the contrary has vanishing capacity, while its complement has positive capacity instead. Thus, quantum states can be reconstructed faithfully behind the black hole horizon, but not outside. This work sheds new light on black hole complementarity because it shows that black holes can both reflect and absorb quantum states without violating the no-cloning theorem, and makes quantum firewalls obsolete.
Duality quantum algorithm efficiently simulates open quantum systems
Wei, Shi-Jie; Ruan, Dong; Long, Gui-Lu
2016-01-01
Because of inevitable coupling with the environment, nearly all practical quantum systems are open system, where the evolution is not necessarily unitary. In this paper, we propose a duality quantum algorithm for simulating Hamiltonian evolution of an open quantum system. In contrast to unitary evolution in a usual quantum computer, the evolution operator in a duality quantum computer is a linear combination of unitary operators. In this duality quantum algorithm, the time evolution of the open quantum system is realized by using Kraus operators which is naturally implemented in duality quantum computer. This duality quantum algorithm has two distinct advantages compared to existing quantum simulation algorithms with unitary evolution operations. Firstly, the query complexity of the algorithm is O(d3) in contrast to O(d4) in existing unitary simulation algorithm, where d is the dimension of the open quantum system. Secondly, By using a truncated Taylor series of the evolution operators, this duality quantum algorithm provides an exponential improvement in precision compared with previous unitary simulation algorithm. PMID:27464855
Interfacing External Quantum Devices to a Universal Quantum Computer
Lagana, Antonio A.; Lohe, Max A.; von Smekal, Lorenz
2011-01-01
We present a scheme to use external quantum devices using the universal quantum computer previously constructed. We thereby show how the universal quantum computer can utilize networked quantum information resources to carry out local computations. Such information may come from specialized quantum devices or even from remote universal quantum computers. We show how to accomplish this by devising universal quantum computer programs that implement well known oracle based quantum algorithms, namely the Deutsch, Deutsch-Jozsa, and the Grover algorithms using external black-box quantum oracle devices. In the process, we demonstrate a method to map existing quantum algorithms onto the universal quantum computer. PMID:22216276
Interfacing external quantum devices to a universal quantum computer.
Lagana, Antonio A; Lohe, Max A; von Smekal, Lorenz
2011-01-01
We present a scheme to use external quantum devices using the universal quantum computer previously constructed. We thereby show how the universal quantum computer can utilize networked quantum information resources to carry out local computations. Such information may come from specialized quantum devices or even from remote universal quantum computers. We show how to accomplish this by devising universal quantum computer programs that implement well known oracle based quantum algorithms, namely the Deutsch, Deutsch-Jozsa, and the Grover algorithms using external black-box quantum oracle devices. In the process, we demonstrate a method to map existing quantum algorithms onto the universal quantum computer. © 2011 Lagana et al.
Quantum algorithms for quantum field theories.
Jordan, Stephen P; Lee, Keith S M; Preskill, John
2012-06-01
Quantum field theory reconciles quantum mechanics and special relativity, and plays a central role in many areas of physics. We developed a quantum algorithm to compute relativistic scattering probabilities in a massive quantum field theory with quartic self-interactions (φ(4) theory) in spacetime of four and fewer dimensions. Its run time is polynomial in the number of particles, their energy, and the desired precision, and applies at both weak and strong coupling. In the strong-coupling and high-precision regimes, our quantum algorithm achieves exponential speedup over the fastest known classical algorithm.
Abstract quantum computing machines and quantum computational logics
NASA Astrophysics Data System (ADS)
Chiara, Maria Luisa Dalla; Giuntini, Roberto; Sergioli, Giuseppe; Leporini, Roberto
2016-06-01
Classical and quantum parallelism are deeply different, although it is sometimes claimed that quantum Turing machines are nothing but special examples of classical probabilistic machines. We introduce the concepts of deterministic state machine, classical probabilistic state machine and quantum state machine. On this basis, we discuss the question: To what extent can quantum state machines be simulated by classical probabilistic state machines? Each state machine is devoted to a single task determined by its program. Real computers, however, behave differently, being able to solve different kinds of problems. This capacity can be modeled, in the quantum case, by the mathematical notion of abstract quantum computing machine, whose different programs determine different quantum state machines. The computations of abstract quantum computing machines can be linguistically described by the formulas of a particular form of quantum logic, termed quantum computational logic.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Goldsmith, Benjamin; Tucker, Kai; Conway, Robert Greg
2013-03-01
Purpose: There is strong interest in partial-bladder radiation whether as a boost or definitive therapy to limit long-term toxicity. It is unclear that a standard preoperative examination can accurately identify all sites of disease within the bladder. The purpose of this study was to determine the correlation between preoperative localization of bladder tumors with postoperative findings to facilitate partial-bladder radiation techniques when appropriate. Methods and Materials: We examined patients with clinically staged T1-T4 invasive transitional cell carcinoma (TCC) or TCC with variant histology with no history of radiation or partial cystectomy undergoing radical cystectomy. Patients were scored as “under-detected” ifmore » a bladder site was involved with invasive disease (≥T1) at the time of cystectomy, but not identified preoperatively. Patients were additionally scored as “widely under-detected” if they had postoperative lesions that were not identified preoperatively in a given site, nor in any adjacent site. Rates of under-detected and widely under-detected lesions, as well as univariate and multivariate association between clinical variables and under-detection, were evaluated using logistic regression. Results: Among 222 patients, 96% (213/222) had at least 1 area of discordance. Fifty-eight percent of patients were under-detected in at least 1 location, whereas 12% were widely under-detected. Among 24 patients with a single site of disease on preoperative evaluation, 21/24 (88%) had at least 1 under-detected lesion and 14/24 (58%) were widely under-detected. On multivariate analysis, only solitary site of preoperative disease was associated with increased levels of under-detection of invasive disease (OR = 4.161, 95% CI, 1.368-12.657). Conclusion: Our study shows a stark discordance between preoperative and postoperative localization of bladder tumors. From a clinical perspective, incomplete localization of all sites of disease within the
Dissipative quantum computing with open quantum walks
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sinayskiy, Ilya; Petruccione, Francesco
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.
Wang, Yanlin; Chen, Yan; Tian, Feng; Zhang, Jianguang; Song, Zhuo; Wu, Yi; Han, Xu; Hu, Wenjing; Ma, Duan; Cram, David; Cheng, Weiwei
2014-01-01
In the human fetus, sex chromosome aneuploidies (SCAs) are as prevalent as the common autosomal trisomies 21, 18, and 13. Currently, most noninvasive prenatal tests (NIPTs) offer screening only for chromosomes 21, 18, and 13, because the sensitivity and specificity are markedly higher than for the sex chromosomes. Limited studies suggest that the reduced accuracy associated with detecting SCAs is due to confined placental, placental, or true fetal mosaicism. We hypothesized that an altered maternal karyotype may also be an important contributor to discordant SCA NIPT results. We developed a rapid karyotyping method that uses massively parallel sequencing to measure the degree of chromosome mosaicism. The method was validated with DNA models mimicking XXX and XO mosaicism and then applied to maternal white blood cell (WBC) DNA from patients with discordant SCA NIPT results. Sequencing karyotyping detected chromosome X (ChrX) mosaicism as low as 5%, allowing an accurate assignment of the maternal X karyotype. In a prospective NIPT study, we showed that 16 (8.6%) of 181 positive SCAs were due to an abnormal maternal ChrX karyotype that masked the true contribution of the fetal ChrX DNA fraction. The accuracy of NIPT for ChrX and ChrY can be improved substantially by integrating the results of maternal-plasma sequencing with those for maternal-WBC sequencing. The relatively high frequency of maternal mosaicism warrants mandatory WBC testing in both shotgun sequencing- and single-nucleotide polymorphism-based clinical NIPT after the finding of a potential fetal SCA.
NASA Technical Reports Server (NTRS)
Bungo, M. W.; Leland, O. S., Jr.
1983-01-01
Eighty-one patients with diagnostically difficult clinical presentations suggesting coronary artery disease underwent symptom-limited maximal-exercise treadmill testing (ETT) and exercise radionuclide scanning with thallium-201 followed by coronary angiography. Results showed that in nearly half of the patients (47%) these tests were in agreement, while either exercise thallium or ETT was positive in 94% of patients with coronary artery disease. It was found that agreement between exercise thallium and ETT tests predicted disease in 92% of the instances or excluded disease in 82% of the instances. It is concluded that despite frequent discord between these two tests in 53% of the cases, a significant gain in exclusive diagnostic capability is realized when applied to a patient population anticipated to have a disease prevalence equal to the 67% encountered in this study.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Johansson, H.; Kanis, J. A.; Oden, A.
There are occasional marked discordances in BMD T-scores at the lumbar spine (LS) and femoral neck (FN). We investigated whether such discordances could contribute independently to fracture prediction using FRAX. In this paper, we studied 21,158 women, average age 63 years, from 10 prospective cohorts with baseline FRAX variables as well as FN and LS BMD. Incident fractures were collected by self-report and/or radiographic reports. Extended Poisson regression examined the relationship between differences in LS and FN T-scores (ΔLS–FN) and fracture risk, adjusted for age, time since baseline and other factors including FRAX 10-year probability for major osteoporotic fracture calculatedmore » using FN BMD. To examine the effect of an adjustment for ΔLS–FN on reclassification, women were separated into risk categories by their FRAX major fracture probability. High risk was classified using two approaches: being above the National Osteoporosis Guideline Group intervention threshold or, separately, being in the highest third of each cohort. The absolute ΔLS–FN was greater than 2 SD for 2.5 % of women and between 1 and 2 SD for 21 %. ΔLS–FN was associated with a significant risk of fracture adjusted for baseline FRAX (HR per SD change = 1.09; 95 % CI = 1.04–1.15). In reclassification analyses, only 2.3–3.2 % of the women moved to a higher or lower risk category when using FRAX with ΔLS–FN compared with FN-derived FRAX alone. Adjustment of estimated fracture risk for a large LS/FN discrepancy (>2SD) impacts to a large extent on only a relatively small number of individuals. More moderate (1–2SD) discordances in FN and LS T-scores have a small impact on FRAX probabilities. Finally, this might still improve clinical decision-making, particularly in women with probabilities close to an intervention threshold.« less
Johansson, H.; Kanis, J. A.; Oden, A.; ...
2014-09-04
There are occasional marked discordances in BMD T-scores at the lumbar spine (LS) and femoral neck (FN). We investigated whether such discordances could contribute independently to fracture prediction using FRAX. In this paper, we studied 21,158 women, average age 63 years, from 10 prospective cohorts with baseline FRAX variables as well as FN and LS BMD. Incident fractures were collected by self-report and/or radiographic reports. Extended Poisson regression examined the relationship between differences in LS and FN T-scores (ΔLS–FN) and fracture risk, adjusted for age, time since baseline and other factors including FRAX 10-year probability for major osteoporotic fracture calculatedmore » using FN BMD. To examine the effect of an adjustment for ΔLS–FN on reclassification, women were separated into risk categories by their FRAX major fracture probability. High risk was classified using two approaches: being above the National Osteoporosis Guideline Group intervention threshold or, separately, being in the highest third of each cohort. The absolute ΔLS–FN was greater than 2 SD for 2.5 % of women and between 1 and 2 SD for 21 %. ΔLS–FN was associated with a significant risk of fracture adjusted for baseline FRAX (HR per SD change = 1.09; 95 % CI = 1.04–1.15). In reclassification analyses, only 2.3–3.2 % of the women moved to a higher or lower risk category when using FRAX with ΔLS–FN compared with FN-derived FRAX alone. Adjustment of estimated fracture risk for a large LS/FN discrepancy (>2SD) impacts to a large extent on only a relatively small number of individuals. More moderate (1–2SD) discordances in FN and LS T-scores have a small impact on FRAX probabilities. Finally, this might still improve clinical decision-making, particularly in women with probabilities close to an intervention threshold.« less
QUANTUM: The Exhibition - quantum at the museum
NASA Astrophysics Data System (ADS)
Laforest, Martin; Olano, Angela; Day-Hamilton, Tobi
Distilling the essence of quantum phenomena, and how they are being harnessed to develop powerful quantum technologies, into a series of bite-sized, elementary-school-level pieces is what the scientific outreach team at the University of Waterloo's Institute for Quantum Computing was tasked with. QUANTUM: The Exhibition uses a series of informational panels, multimedia and interactive displays to introduce visitors to quantum phenomena and how they will revolutionize computing, information security and sensing. We'll discuss some of the approaches we took to convey the essence and impact of quantum mechanics and technologies to a lay audience while ensuring scientific accuracy.
Quantum thermodynamics of general quantum processes.
Binder, Felix; Vinjanampathy, Sai; Modi, Kavan; Goold, John
2015-03-01
Accurately describing work extraction from a quantum system is a central objective for the extension of thermodynamics to individual quantum systems. The concepts of work and heat are surprisingly subtle when generalizations are made to arbitrary quantum states. We formulate an operational thermodynamics suitable for application to an open quantum system undergoing quantum evolution under a general quantum process by which we mean a completely positive and trace-preserving map. We derive an operational first law of thermodynamics for such processes and show consistency with the second law. We show that heat, from the first law, is positive when the input state of the map majorizes the output state. Moreover, the change in entropy is also positive for the same majorization condition. This makes a strong connection between the two operational laws of thermodynamics.
Quantum simulations with noisy quantum computers
NASA Astrophysics Data System (ADS)
Gambetta, Jay
Quantum computing is a new computational paradigm that is expected to lie beyond the standard model of computation. This implies a quantum computer can solve problems that can't be solved by a conventional computer with tractable overhead. To fully harness this power we need a universal fault-tolerant quantum computer. However the overhead in building such a machine is high and a full solution appears to be many years away. Nevertheless, we believe that we can build machines in the near term that cannot be emulated by a conventional computer. It is then interesting to ask what these can be used for. In this talk we will present our advances in simulating complex quantum systems with noisy quantum computers. We will show experimental implementations of this on some small quantum computers.
Quantum optics, cavity QED, and quantum optomechanics
NASA Astrophysics Data System (ADS)
Meystre, Pierre
2013-05-01
Quantum optomechanics provides a universal tool to achieve the quantum control of mechanical motion. It does that in devices spanning a vast range of parameters, with mechanical frequencies from a few Hertz to GHz, and with masses from 10-20 g to several kilos. Its underlying ideas can be traced back to the study of gravitational wave antennas, quantum optics, cavity QED and laser cooling which, when combined with the recent availability of advanced micromechanical and nanomechanical devices, opens a path to the realization of macroscopic mechanical systems that operate deep in the quantum regime. At the fundamental level this development paves the way to experiments that will lead to a more profound understanding of quantum mechanics; and from the point of view of applications, quantum optomechanical techniques will provide motion and force sensing near the fundamental limit imposed by quantum mechanics (quantum metrology) and significantly expand the toolbox of quantum information science. After a brief summary of key historical developments, the talk will give a broad overview of the current state of the art of quantum optomechanics, and comment on future prospects both in applied and in fundamental science. Work supported by NSF, ARO and the DARPA QuASAR and ORCHID programs.
Exploiting Locality in Quantum Computation for Quantum Chemistry.
McClean, Jarrod R; Babbush, Ryan; Love, Peter J; Aspuru-Guzik, Alán
2014-12-18
Accurate prediction of chemical and material properties from first-principles quantum chemistry is a challenging task on traditional computers. Recent developments in quantum computation offer a route toward highly accurate solutions with polynomial cost; however, this solution still carries a large overhead. In this Perspective, we aim to bring together known results about the locality of physical interactions from quantum chemistry with ideas from quantum computation. We show that the utilization of spatial locality combined with the Bravyi-Kitaev transformation offers an improvement in the scaling of known quantum algorithms for quantum chemistry and provides numerical examples to help illustrate this point. We combine these developments to improve the outlook for the future of quantum chemistry on quantum computers.
Opportunistic quantum network coding based on quantum teleportation
NASA Astrophysics Data System (ADS)
Shang, Tao; Du, Gang; Liu, Jian-wei
2016-04-01
It seems impossible to endow opportunistic characteristic to quantum network on the basis that quantum channel cannot be overheard without disturbance. In this paper, we propose an opportunistic quantum network coding scheme by taking full advantage of channel characteristic of quantum teleportation. Concretely, it utilizes quantum channel for secure transmission of quantum states and can detect eavesdroppers by means of quantum channel verification. What is more, it utilizes classical channel for both opportunistic listening to neighbor states and opportunistic coding by broadcasting measurement outcome. Analysis results show that our scheme can reduce the times of transmissions over classical channels for relay nodes and can effectively defend against classical passive attack and quantum active attack.
Quantum stochastic calculus associated with quadratic quantum noises
DOE Office of Scientific and Technical Information (OSTI.GOV)
Ji, Un Cig, E-mail: uncigji@chungbuk.ac.kr; Sinha, Kalyan B., E-mail: kbs-jaya@yahoo.co.in
2016-02-15
We first study a class of fundamental quantum stochastic processes induced by the generators of a six dimensional non-solvable Lie †-algebra consisting of all linear combinations of the generalized Gross Laplacian and its adjoint, annihilation operator, creation operator, conservation, and time, and then we study the quantum stochastic integrals associated with the class of fundamental quantum stochastic processes, and the quantum Itô formula is revisited. The existence and uniqueness of solution of a quantum stochastic differential equation is proved. The unitarity conditions of solutions of quantum stochastic differential equations associated with the fundamental processes are examined. The quantum stochastic calculusmore » extends the Hudson-Parthasarathy quantum stochastic calculus.« less
Some foundational aspects of quantum computers and quantum robots.
DOE Office of Scientific and Technical Information (OSTI.GOV)
Benioff, P.; Physics
1998-01-01
This paper addresses foundational issues related to quantum computing. The need for a universally valid theory such as quantum mechanics to describe to some extent its own validation is noted. This includes quantum mechanical descriptions of systems that do theoretical calculations (i.e. quantum computers) and systems that perform experiments. Quantum robots interacting with an environment are a small first step in this direction. Quantum robots are described here as mobile quantum systems with on-board quantum computers that interact with environments. Included are discussions on the carrying out of tasks and the division of tasks into computation and action phases. Specificmore » models based on quantum Turing machines are described. Differences and similarities between quantum robots plus environments and quantum computers are discussed.« less
Single-server blind quantum computation with quantum circuit model
NASA Astrophysics Data System (ADS)
Zhang, Xiaoqian; Weng, Jian; Li, Xiaochun; Luo, Weiqi; Tan, Xiaoqing; Song, Tingting
2018-06-01
Blind quantum computation (BQC) enables the client, who has few quantum technologies, to delegate her quantum computation to a server, who has strong quantum computabilities and learns nothing about the client's quantum inputs, outputs and algorithms. In this article, we propose a single-server BQC protocol with quantum circuit model by replacing any quantum gate with the combination of rotation operators. The trap quantum circuits are introduced, together with the combination of rotation operators, such that the server is unknown about quantum algorithms. The client only needs to perform operations X and Z, while the server honestly performs rotation operators.
Starr, Lisa R; Hammen, Constance
2016-05-01
Studies support a link between adolescent romantic involvement and depression. Adolescent romantic relationships may increase depression risk by introducing chronic stress, and genetic vulnerability to stress reactivity/emotion dysregulation may moderate these associations. We tested genetic moderation of longitudinal associations between adolescent romantic involvement and later depressive symptoms by a polymorphism in the serotonin transporter linked polymorphic region gene (5-HTTLPR) and examined contributory roles of chronic stress and family discord. Three hundred eighty-one youth participated at ages 15 and 20. The results indicated that 5-HTTLPR moderated the association between age 15 romantic involvement and age 20 depressive symptoms, with strongest effects for short homozygotes. Conditional process analysis revealed that chronic stress functioned as a moderated mediator of this association, fully accounting for the romantic involvement-depression link among short/short genotypes. Also, romantic involvement predicted later depressive symptoms most strongly among short-allele carriers with high family discord. The results have important implications for understanding the romantic involvement-depression link and the behavioral and emotional correlates of the 5-HTTLPR genotype.
Starr, Lisa R.; Hammen, Constance
2017-01-01
Studies support a link between adolescent romantic involvement and depression. Adolescent romantic relationships may increase depression risk by introducing chronic stress, and genetic vulnerability to stress reactivity/emotion dysregulation may moderate these associations. We tested genetic moderation of longitudinal associations between adolescent romantic involvement and later depressive symptoms by a polymorphism in the serotonin transporter linked polymorphic region gene (5-HTTLPR), and examined contributory roles of chronic stress and family discord. Three hundred eighty-one youth participated at ages 15 and 20. The results indicated that 5-HTTLPR moderated the association between age 15 romantic involvement and age 20 depressive symptoms, with strongest effects for short homozygotes. Conditional process analysis revealed that chronic stress functioned as a moderated mediator of this association, fully accounting for the romantic involvement-depression link among short/short genotypes. Also, romantic involvement predicted later depressive symptoms most strongly among short-allele carriers with high family discord. Results have important implications for understanding the romantic involvement-depression link and the behavioral and emotional Correlates of the 5-HTTLPR genotype. PMID:26037034
Quantum chemistry simulation on quantum computers: theories and experiments.
Lu, Dawei; Xu, Boruo; Xu, Nanyang; Li, Zhaokai; Chen, Hongwei; Peng, Xinhua; Xu, Ruixue; Du, Jiangfeng
2012-07-14
It has been claimed that quantum computers can mimic quantum systems efficiently in the polynomial scale. Traditionally, those simulations are carried out numerically on classical computers, which are inevitably confronted with the exponential growth of required resources, with the increasing size of quantum systems. Quantum computers avoid this problem, and thus provide a possible solution for large quantum systems. In this paper, we first discuss the ideas of quantum simulation, the background of quantum simulators, their categories, and the development in both theories and experiments. We then present a brief introduction to quantum chemistry evaluated via classical computers followed by typical procedures of quantum simulation towards quantum chemistry. Reviewed are not only theoretical proposals but also proof-of-principle experimental implementations, via a small quantum computer, which include the evaluation of the static molecular eigenenergy and the simulation of chemical reaction dynamics. Although the experimental development is still behind the theory, we give prospects and suggestions for future experiments. We anticipate that in the near future quantum simulation will become a powerful tool for quantum chemistry over classical computations.
Quantum logic using correlated one-dimensional quantum walks
NASA Astrophysics Data System (ADS)
Lahini, Yoav; Steinbrecher, Gregory R.; Bookatz, Adam D.; Englund, Dirk
2018-01-01
Quantum Walks are unitary processes describing the evolution of an initially localized wavefunction on a lattice potential. The complexity of the dynamics increases significantly when several indistinguishable quantum walkers propagate on the same lattice simultaneously, as these develop non-trivial spatial correlations that depend on the particle's quantum statistics, mutual interactions, initial positions, and the lattice potential. We show that even in the simplest case of a quantum walk on a one dimensional graph, these correlations can be shaped to yield a complete set of compact quantum logic operations. We provide detailed recipes for implementing quantum logic on one-dimensional quantum walks in two general cases. For non-interacting bosons—such as photons in waveguide lattices—we find high-fidelity probabilistic quantum gates that could be integrated into linear optics quantum computation schemes. For interacting quantum-walkers on a one-dimensional lattice—a situation that has recently been demonstrated using ultra-cold atoms—we find deterministic logic operations that are universal for quantum information processing. The suggested implementation requires minimal resources and a level of control that is within reach using recently demonstrated techniques. Further work is required to address error-correction.
Long distance quantum communication with quantum Reed-Solomon codes
NASA Astrophysics Data System (ADS)
Muralidharan, Sreraman; Zou, Chang-Ling; Li, Linshu; Jiang, Liang; Jianggroup Team
We study the construction of quantum Reed Solomon codes from classical Reed Solomon codes and show that they achieve the capacity of quantum erasure channel for multi-level quantum systems. We extend the application of quantum Reed Solomon codes to long distance quantum communication, investigate the local resource overhead needed for the functioning of one-way quantum repeaters with these codes, and numerically identify the parameter regime where these codes perform better than the known quantum polynomial codes and quantum parity codes . Finally, we discuss the implementation of these codes into time-bin photonic states of qubits and qudits respectively, and optimize the performance for one-way quantum repeaters.
Reliable quantum communication over a quantum relay channel
DOE Office of Scientific and Technical Information (OSTI.GOV)
Gyongyosi, Laszlo, E-mail: gyongyosi@hit.bme.hu; Imre, Sandor
2014-12-04
We show that reliable quantum communication over an unreliable quantum relay channels is possible. The coding scheme combines the results on the superadditivity of quantum channels and the efficient quantum coding approaches.
Novel systems and methods for quantum communication, quantum computation, and quantum simulation
NASA Astrophysics Data System (ADS)
Gorshkov, Alexey Vyacheslavovich
Precise control over quantum systems can enable the realization of fascinating applications such as powerful computers, secure communication devices, and simulators that can elucidate the physics of complex condensed matter systems. However, the fragility of quantum effects makes it very difficult to harness the power of quantum mechanics. In this thesis, we present novel systems and tools for gaining fundamental insights into the complex quantum world and for bringing practical applications of quantum mechanics closer to reality. We first optimize and show equivalence between a wide range of techniques for storage of photons in atomic ensembles. We describe experiments demonstrating the potential of our optimization algorithms for quantum communication and computation applications. Next, we combine the technique of photon storage with strong atom-atom interactions to propose a robust protocol for implementing the two-qubit photonic phase gate, which is an important ingredient in many quantum computation and communication tasks. In contrast to photon storage, many quantum computation and simulation applications require individual addressing of closely-spaced atoms, ions, quantum dots, or solid state defects. To meet this requirement, we propose a method for coherent optical far-field manipulation of quantum systems with a resolution that is not limited by the wavelength of radiation. While alkali atoms are currently the system of choice for photon storage and many other applications, we develop new methods for quantum information processing and quantum simulation with ultracold alkaline-earth atoms in optical lattices. We show how multiple qubits can be encoded in individual alkaline-earth atoms and harnessed for quantum computing and precision measurements applications. We also demonstrate that alkaline-earth atoms can be used to simulate highly symmetric systems exhibiting spin-orbital interactions and capable of providing valuable insights into strongly
Beable-guided quantum theories: Generalizing quantum probability laws
NASA Astrophysics Data System (ADS)
Kent, Adrian
2013-02-01
Beable-guided quantum theories (BGQT) are generalizations of quantum theory, inspired by Bell's concept of beables. They modify the quantum probabilities for some specified set of fundamental events, histories, or other elements of quasiclassical reality by probability laws that depend on the realized configuration of beables. For example, they may define an additional probability weight factor for a beable configuration, independent of the quantum dynamics. Beable-guided quantum theories can be fitted to observational data to provide foils against which to compare explanations based on standard quantum theory. For example, a BGQT could, in principle, characterize the effects attributed to dark energy or dark matter, or any other deviation from the predictions of standard quantum dynamics, without introducing extra fields or a cosmological constant. The complexity of the beable-guided theory would then parametrize how far we are from a standard quantum explanation. Less conservatively, we give reasons for taking suitably simple beable-guided quantum theories as serious phenomenological theories in their own right. Among these are the possibility that cosmological models defined by BGQT might in fact fit the empirical data better than any standard quantum explanation, and the fact that BGQT suggest potentially interesting nonstandard ways of coupling quantum matter to gravity.
Rhodes, Ryan E; Yao, Christopher A
2015-02-07
There is a growing concern among researchers with the limited effectiveness and yet subsequent stagnation of theories applied to physical activity (PA). One of the most highlighted areas of concern is the established gap between intention and PA, yet the considerable use of models that assume intention is the proximal antecedent of PA. The objective of this review was to: 1) provide a guide and thematic analysis of the available models that include constructs that address intention-behavior discordance and 2) highlight the evidence for these structures in the PA domain. A literature search was conducted among 13 major databases to locate relevant models and PA studies published before August 2014. Sixteen models were identified and nine overall themes for post-intentional constructs were created. Of the 16 models, eight were applied to 36 PA studies. Early evidence supported maintenance self-efficacy, behavioral regulation strategies, affective judgments, perceived control/opportunity, habit, and extraversion as reliable predictors of post-intention PA. Several intention-behavior discordance models exist within the literature, but are not used frequently. Further efforts are needed to test these models, preferably with experimental designs.
Degenerate quantum codes and the quantum Hamming bound
DOE Office of Scientific and Technical Information (OSTI.GOV)
Sarvepalli, Pradeep; Klappenecker, Andreas
2010-03-15
The parameters of a nondegenerate quantum code must obey the Hamming bound. An important open problem in quantum coding theory is whether the parameters of a degenerate quantum code can violate this bound for nondegenerate quantum codes. In this article we show that Calderbank-Shor-Steane (CSS) codes, over a prime power alphabet q{>=}5, cannot beat the quantum Hamming bound. We prove a quantum version of the Griesmer bound for the CSS codes, which allows us to strengthen the Rains' bound that an [[n,k,d
Preparation of freezing quantum state for quantum coherence
NASA Astrophysics Data System (ADS)
Yang, Lian-Wu; Man, Zhong-Xiao; Zhang, Ying-Jie; Han, Feng; Du, Shao-jiang; Xia, Yun-Jie
2018-06-01
We provide a method to prepare the freezing quantum state for quantum coherence via unitary operations. The initial product state consists of the control qubit and target qubit; when it satisfies certain conditions, the initial product state converts into the particular Bell diagonal state under the unitary operations, which have the property of freezing of quantum coherence under quantum channels. We calculate the frozen quantum coherence and corresponding quantum correlations, and find that the quantities are determined by the control qubit only when the freezing phenomena occur.
Gu, Danan; Feng, Qiushi; Sautter, Jessica M; Yang, Fang; Ma, Lei; Zhen, Zhihong
2017-03-01
To investigate subtypes of successful aging (SA) based on concordance and discordance between self-rated and researcher-defined measures and their associations with demographic, psychosocial, and life satisfaction factors. We used multinomial logistic regression models to analyze 2013 cross-sectional survey data from 1,962 persons aged 65 and older in Shanghai that measured self-rated successful aging (SSA) with a single global assessment and researcher-defined successful aging (RSA) with a cumulative deficit index reflecting physical, physiological, cognitive, psychological, and social engagement domains. We generated four subtypes based on these two dichotomous variables: nonsuccessful aging (non-SA; meeting neither the criterion of RSA nor the criterion of SSA), RSA-only (meeting the criterion of RSA-only but not the criterion of SSA), SSA-only (meeting the criterion of SSA-only but not the criterion of RSA), and both-successful aging (both-SA; meeting both criteria of RSA and SSA). In the sample, 32% were nonsuccessful agers, 7% RSA-only, 34% SSA-only, and 27% successful agers. Female gender and older age were associated with lower likelihood of RSA-only and both-SA relative to non-SA, but with greater likelihood of SSA-only. Good socioeconomic conditions and social networks were associated with greater likelihood of SSA-only and both-SA relative to non-SA or RSA-only. Satisfaction with life domains was robustly and positively associated with good successful aging outcomes. Researcher-defined successful aging and self-rated successful aging are different measures with distinct social correlates. Subtypes of concordance and discordance provide a more holistic biopsychosocial conceptualization of successful aging. © The Author 2016. Published by Oxford University Press on behalf of The Gerontological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.
Quantum dot quantum cascade infrared photodetector
DOE Office of Scientific and Technical Information (OSTI.GOV)
Wang, Xue-Jiao; Zhai, Shen-Qiang; Zhuo, Ning
2014-04-28
We demonstrate an InAs quantum dot quantum cascade infrared photodetector operating at room temperature with a peak detection wavelength of 4.3 μm. The detector shows sensitive photoresponse for normal-incidence light, which is attributed to an intraband transition of the quantum dots and the following transfer of excited electrons on a cascade of quantum levels. The InAs quantum dots for the infrared absorption were formed by making use of self-assembled quantum dots in the Stranski–Krastanov growth mode and two-step strain-compensation design based on InAs/GaAs/InGaAs/InAlAs heterostructure, while the following extraction quantum stairs formed by LO-phonon energy are based on a strain-compensated InGaAs/InAlAs chirpedmore » superlattice. Johnson noise limited detectivities of 3.64 × 10{sup 11} and 4.83 × 10{sup 6} Jones at zero bias were obtained at 80 K and room temperature, respectively. Due to the low dark current and distinct photoresponse up to room temperature, this device can form high temperature imaging.« less
Quantum Darwinism in Quantum Brownian Motion
NASA Astrophysics Data System (ADS)
Blume-Kohout, Robin; Zurek, Wojciech H.
2008-12-01
Quantum Darwinism—the redundant encoding of information about a decohering system in its environment—was proposed to reconcile the quantum nature of our Universe with apparent classicality. We report the first study of the dynamics of quantum Darwinism in a realistic model of decoherence, quantum Brownian motion. Prepared in a highly squeezed state—a macroscopic superposition—the system leaves records whose redundancy increases rapidly with initial delocalization. Redundancy appears rapidly (on the decoherence time scale) and persists for a long time.
Quantum Darwinism in quantum Brownian motion.
Blume-Kohout, Robin; Zurek, Wojciech H
2008-12-12
Quantum Darwinism--the redundant encoding of information about a decohering system in its environment--was proposed to reconcile the quantum nature of our Universe with apparent classicality. We report the first study of the dynamics of quantum Darwinism in a realistic model of decoherence, quantum Brownian motion. Prepared in a highly squeezed state--a macroscopic superposition--the system leaves records whose redundancy increases rapidly with initial delocalization. Redundancy appears rapidly (on the decoherence time scale) and persists for a long time.
Quantum Quasi-Paradoxes and Quantum Sorites Paradoxes
NASA Astrophysics Data System (ADS)
Smarandache, Florentin
2009-03-01
There can be generated many paradoxes or quasi-paradoxes that may occur from the combination of quantum and non-quantum worlds in physics. Even the passage from the micro-cosmos to the macro-cosmos, and reciprocally, can generate unsolved questions or counter-intuitive ideas. We define a quasi-paradox as a statement which has a prima facie self-contradictory support or an explicit contradiction, but which is not completely proven as a paradox. We present herein four elementary quantum quasi-paradoxes and their corresponding quantum Sorites paradoxes, which form a class of quantum quasi-paradoxes.
ERIC Educational Resources Information Center
Rubenstein, Eric; Edmondson Pretzel, Rebecca; Windham, Gayle C.; Schieve, Laura A.; Wiggins, Lisa D.; DiGuiseppi, Carolyn; Olshan, Andrew F.; Howard, Annie G.; Pence, Brian W.; Young, Lisa; Daniels, Julie
2017-01-01
Autism spectrum disorder (ASD) diagnosis relies on parent-reported and clinician-observed instruments. Sometimes, results between these instruments disagree. The broader autism phenotype (BAP) in parent-reporters may be associated with discordance. Study to Explore Early Development data (N = 712) were used to address whether mothers with BAP and…
Partner communication, discordant fertility goals, and contraceptive use in urban Kenya
Tumlinson, Katherine; Speizer, Ilene S.; Davis, Joshua T.; Fotso, Jean Christophe; Kuria, Paul; Archer, Linda
2013-01-01
This study assesses the degree of partner communication and perceived partner concordance and their association with contraceptive use among 2,891 women and 1,362 men in urban Kenya. Twenty-three percent of men and 30% of women report never discussing FP with their partner. Approximately 70% of participants perceive their partner to have concordant fertility desires. Multivariate analyses revealed that both male (AOR = 7.7 [95% CI = 5.5–10.7]) and female (AOR = 2.8 [95% CI = 2.3–3.3]) participants were more likely to use contraception if they report discussing FP with their partner. Participants who perceive that their partner wants fewer children also were more likely to use contraception (AOR, females = 1.8 [95% CI = 1.2–2.8]), (AOR, males = 1.9 [95% CI = 1.2–3.1]). Discussion of FP is a key determinant of contraceptive use; in couples with discordant fertility goals, pro-natalist males do not always dictate contraceptive behavior in urban Kenya. PMID:24069770
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
Quantum simulation of a quantum stochastic walk
NASA Astrophysics Data System (ADS)
Govia, Luke C. G.; Taketani, Bruno G.; Schuhmacher, Peter K.; Wilhelm, Frank K.
2017-03-01
The study of quantum walks has been shown to have a wide range of applications in areas such as artificial intelligence, the study of biological processes, and quantum transport. The quantum stochastic walk (QSW), which allows for incoherent movement of the walker, and therefore, directionality, is a generalization on the fully coherent quantum walk. While a QSW can always be described in Lindblad formalism, this does not mean that it can be microscopically derived in the standard weak-coupling limit under the Born-Markov approximation. This restricts the class of QSWs that can be experimentally realized in a simple manner. To circumvent this restriction, we introduce a technique to simulate open system evolution on a fully coherent quantum computer, using a quantum trajectories style approach. We apply this technique to a broad class of QSWs, and show that they can be simulated with minimal experimental resources. Our work opens the path towards the experimental realization of QSWs on large graphs with existing quantum technologies.
Kooren, Joel A.; Parker, Sarah J.; Tucker, Kyle C.; Ravindran, Nandini; Ito, Bruce R.; Huang, Chengqun; Venkatraman, Vidya; Van Eyk, Jennifer E.; Gottlieb, Roberta A.; Mentzer, Robert M.
2016-01-01
Autophagy is regulated by nutrient and energy status and plays an adaptive role during nutrient deprivation and ischemic stress. Metabolic syndrome (MetS) is a hypernutritive state characterized by obesity, dyslipidemia, elevated fasting blood glucose levels, and insulin resistance. It has also been associated with impaired autophagic flux and larger-sized infarcts. We hypothesized that diet-induced obesity (DIO) affects nutrient sensing, explaining the observed cardiac impaired autophagy. We subjected male friend virus B NIH (FVBN) mice to a high-fat diet, which resulted in increased weight gain, fat deposition, hyperglycemia, insulin resistance, and larger infarcts after myocardial ischemia-reperfusion. Autophagic flux was impaired after 4 wk on a high-fat diet. To interrogate nutrient-sensing pathways, DIO mice were subjected to overnight fasting, and hearts were processed for biochemical and proteomic analysis. Obese mice failed to upregulate LC3-II or to clear p62/SQSTM1 after fasting, although mRNA for LC3B and p62/SQSTM1 were appropriately upregulated in both groups, demonstrating an intact transcriptional response to fasting. Energy- and nutrient-sensing signal transduction pathways [AMPK and mammalian target of rapamycin (mTOR)] also responded appropriately to fasting, although mTOR was more profoundly suppressed in obese mice. Proteomic quantitative analysis of the hearts under fed and fasted conditions revealed broad changes in protein networks involved in oxidative phosphorylation, autophagy, oxidative stress, protein homeostasis, and contractile machinery. In many instances, the fasting response was quite discordant between lean and DIO mice. Network analysis implicated the peroxisome proliferator-activated receptor and mTOR regulatory nodes. Hearts of obese mice exhibited impaired autophagy, altered proteome, and discordant response to nutrient deprivation. PMID:27199111
Hybrid quantum-classical modeling of quantum dot devices
NASA Astrophysics Data System (ADS)
Kantner, Markus; Mittnenzweig, Markus; Koprucki, Thomas
2017-11-01
The design of electrically driven quantum dot devices for quantum optical applications asks for modeling approaches combining classical device physics with quantum mechanics. We connect the well-established fields of semiclassical semiconductor transport theory and the theory of open quantum systems to meet this requirement. By coupling the van Roosbroeck system with a quantum master equation in Lindblad form, we introduce a new hybrid quantum-classical modeling approach, which provides a comprehensive description of quantum dot devices on multiple scales: it enables the calculation of quantum optical figures of merit and the spatially resolved simulation of the current flow in realistic semiconductor device geometries in a unified way. We construct the interface between both theories in such a way, that the resulting hybrid system obeys the fundamental axioms of (non)equilibrium thermodynamics. We show that our approach guarantees the conservation of charge, consistency with the thermodynamic equilibrium and the second law of thermodynamics. The feasibility of the approach is demonstrated by numerical simulations of an electrically driven single-photon source based on a single quantum dot in the stationary and transient operation regime.
Brandt, Frans; Thvilum, Marianne; Hegedüs, Laszlo; Brix, Thomas Heiberg
2015-11-01
To examine the risk of disability pension and changes in labour market income in patients with hyperthyroidism. From a 5% random sample of the Danish population and twins from the Danish Twin Registry we identified 1942 hyperthyroid singletons and 7768 non-hyperthyroid (matched 1:4) controls as well as 584 same-sex twin pairs discordant for hyperthyroidism. Singletons and twins were followed for a mean of 9 years (range 1-20). Cox regression analysis was used to examine the risk of disability pension and a difference-in-differences model was used to evaluate changes in labour market income. Hyperthyroid individuals had an increased risk of receiving disability pension: hazard ratio (HR) was 1.88, (95% CI: 1.57-2.24). Subdividing as to the cause of hyperthyroidism did not change this finding: Graves' disease (GD) HR was 1.51 (95% CI: 0.87-2.63) and toxic nodular goitre (TNG) HR was 2.10 (95% CI: 1.02-4.36). With respect to labour market income, the income of hyperthyroid individuals increased on average 1189 € less than their controls (P<0.001). This difference in income was more pronounced in GD (2539 €) than in TNG (132 €). Essentially similar results, with respect to disability pension and labour market income, were seen within monozygotic twin pairs discordant for hyperthyroidism. Hyperthyroidism is associated with severe work disability as reflected by an 88% increased risk of receiving disability pension and a significant loss of labour market income. Similar results in monozygotic twins discordant for hyperthyroidism suggest that genetic confounding is unlikely. © 2015 European Society of Endocrinology.
Zafer, Maryam; Horvath, Hacsi; Mmeje, Okeoma; van der Poel, Sheryl; Semprini, Augusto E; Rutherford, George; Brown, Joelle
2016-03-01
To evaluate the effectiveness of semen washing in human immunodeficiency virus (HIV)-discordant couples in which the male partner is infected. Systematic review and meta-analysis. Not applicable. Forty single-arm open-label studies among HIV-discordant couples that underwent intrauterine insemination (IUI) or in vitro fertilization (IVF) with or without intracytoplasmic sperm injection (ICSI) using washed semen. Semen washing followed by IUI, IVF, or IVF/ICSI. HIV transmission to HIV-uninfected women; secondary outcomes: HIV transmission to newborns and proportion of couples achieving a clinical pregnancy. No HIV transmission occurred in 11,585 cycles of assisted reproduction with the use of washed semen among 3,994 women. Among the subset of HIV-infected men without plasma viral suppression at the time of semen washing, no HIV seroconversions occurred among 1,023 women after 2,863 cycles of assisted reproduction with the use of washed semen. Studies that measured HIV transmission to infants reported no cases of vertical transmission. Overall, 56.3% of couples (2,357/4,184) achieved a clinical pregnancy with the use of washed semen. Semen washing appears to significantly reduce the risk of transmission in HIV-discordant couples desiring children, regardless of viral suppression in the male partner. There are no randomized controlled studies or studies from low-income countries, especially those with a large burden of HIV. Continued development of lower-cost semen washing and assisted reproduction technologies is needed. Integration of semen washing into HIV prevention interventions could help to further reduce the spread of HIV. Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.
Nugent, Stephen D; Kaats, Gilbert R; Preuss, Harry G
2018-01-01
A general assumption is that the body mass index (BMI) reflects changes in fat mass (FM). However, it fails to distinguish the type of weight that is lost or gained-fat mass (FM) or fat-free mass (FFM). The BMI treats both changes the same although they have opposite health consequences. The objective of this study was to propose a more precise measure, a body composition change index (BCCI), which distinguishes between changes in FM and FFM, and this study compares it with using the BMI as an outcome measure. Data were obtained from 3,870 subjects who had completed dual-energy x-ray absorptiometry (DEXA) total body scans at baseline and end-of-study when participating in a variety of weight-loss interventions. Since height remained constant in this adult cohort, changes in the BMI corresponded with scale weight changes (r = 0.994), allowing BMI changes to be converted to "lbs." to match the statistic used for calculation of the BCCI. The BCCI is calculated by scoring increases in FFM (lbs.) and decreases in FM (lbs.) as positive outcomes and scoring decreases in FFM and increases in FM as negative outcomes. The BCCI is the net sum of these calculations. Differences between scale weight changes and BCCI values were subsequently compared to obtain "discordance scores." Discordance scores ranged from 0.0 lbs. to >30.0 lbs. with a mean absolute value of between the two measures of 7.79 lbs. (99% confidence interval: 7.49-8.10, p <0.00001), SD = 7.4 lbs. Similar discordance scores were also found in subgroups of self-reported gender, ethnicity, and age. A significant difference of 7.79 lbs. was found between the BCCI and the BMI to evaluate the efficacy of weight loss interventions. If assessing changes in body composition is a treatment goal, use of the BMI could result in significantly erroneous conclusions.
One-way quantum repeaters with quantum Reed-Solomon codes
NASA Astrophysics Data System (ADS)
Muralidharan, Sreraman; Zou, Chang-Ling; Li, Linshu; Jiang, Liang
2018-05-01
We show that quantum Reed-Solomon codes constructed from classical Reed-Solomon codes can approach the capacity on the quantum erasure channel of d -level systems for large dimension d . We study the performance of one-way quantum repeaters with these codes and obtain a significant improvement in key generation rate compared to previously investigated encoding schemes with quantum parity codes and quantum polynomial codes. We also compare the three generations of quantum repeaters using quantum Reed-Solomon codes and identify parameter regimes where each generation performs the best.
Layered Architectures for Quantum Computers and Quantum Repeaters
NASA Astrophysics Data System (ADS)
Jones, Nathan C.
This chapter examines how to organize quantum computers and repeaters using a systematic framework known as layered architecture, where machine control is organized in layers associated with specialized tasks. The framework is flexible and could be used for analysis and comparison of quantum information systems. To demonstrate the design principles in practice, we develop architectures for quantum computers and quantum repeaters based on optically controlled quantum dots, showing how a myriad of technologies must operate synchronously to achieve fault-tolerance. Optical control makes information processing in this system very fast, scalable to large problem sizes, and extendable to quantum communication.
Spin-based quantum computation in multielectron quantum dots
NASA Astrophysics Data System (ADS)
Hu, Xuedong; Das Sarma, S.
2001-10-01
In a quantum computer the hardware and software are intrinsically connected because the quantum Hamiltonian (or more precisely its time development) is the code that runs the computer. We demonstrate this subtle and crucial relationship by considering the example of electron-spin-based solid-state quantum computer in semiconductor quantum dots. We show that multielectron quantum dots with one valence electron in the outermost shell do not behave simply as an effective single-spin system unless special conditions are satisfied. Our work compellingly demonstrates that a delicate synergy between theory and experiment (between software and hardware) is essential for constructing a quantum computer.
Architectures for Quantum Simulation Showing a Quantum Speedup
NASA Astrophysics Data System (ADS)
Bermejo-Vega, Juan; Hangleiter, Dominik; Schwarz, Martin; Raussendorf, Robert; Eisert, Jens
2018-04-01
One of the main aims in the field of quantum simulation is to achieve a quantum speedup, often referred to as "quantum computational supremacy," referring to the experimental realization of a quantum device that computationally outperforms classical computers. In this work, we show that one can devise versatile and feasible schemes of two-dimensional, dynamical, quantum simulators showing such a quantum speedup, building on intermediate problems involving nonadaptive, measurement-based, quantum computation. In each of the schemes, an initial product state is prepared, potentially involving an element of randomness as in disordered models, followed by a short-time evolution under a basic translationally invariant Hamiltonian with simple nearest-neighbor interactions and a mere sampling measurement in a fixed basis. The correctness of the final-state preparation in each scheme is fully efficiently certifiable. We discuss experimental necessities and possible physical architectures, inspired by platforms of cold atoms in optical lattices and a number of others, as well as specific assumptions that enter the complexity-theoretic arguments. This work shows that benchmark settings exhibiting a quantum speedup may require little control, in contrast to universal quantum computing. Thus, our proposal puts a convincing experimental demonstration of a quantum speedup within reach in the near term.
Quantum optics. Gravity meets quantum physics
DOE Office of Scientific and Technical Information (OSTI.GOV)
Adams, Bernhard W.
2015-02-27
Albert Einstein’s general theory of relativity is a classical formulation but a quantum mechanical description of gravitational forces is needed, not only to investigate the coupling of classical and quantum systems but simply to give a more complete description of our physical surroundings. In this issue of Nature Photonics, Wen-Te Liao and Sven Ahrens reveal a link between quantum and gravitational physics. They propose that in the quantum-optical effect of superradiance, the world line of electromagnetic radiation is changed by the presence of a gravitational field.
Quantum Koszul formula on quantum spacetime
NASA Astrophysics Data System (ADS)
Majid, Shahn; Williams, Liam
2018-07-01
Noncommutative or quantum Riemannian geometry has been proposed as an effective theory for aspects of quantum gravity. Here the metric is an invertible bimodule map Ω1⊗AΩ1 → A where A is a possibly noncommutative or 'quantum' spacetime coordinate algebra and (Ω1 , d) is a specified bimodule of 1-forms or 'differential calculus' over it. In this paper we explore the proposal of a 'quantum Koszul formula' in Majid [12] with initial data a degree - 2 bilinear map ⊥ on the full exterior algebra Ω obeying the 4-term relations
Scalable quantum computer architecture with coupled donor-quantum dot qubits
Schenkel, Thomas; Lo, Cheuk Chi; Weis, Christoph; Lyon, Stephen; Tyryshkin, Alexei; Bokor, Jeffrey
2014-08-26
A quantum bit computing architecture includes a plurality of single spin memory donor atoms embedded in a semiconductor layer, a plurality of quantum dots arranged with the semiconductor layer and aligned with the donor atoms, wherein a first voltage applied across at least one pair of the aligned quantum dot and donor atom controls a donor-quantum dot coupling. A method of performing quantum computing in a scalable architecture quantum computing apparatus includes arranging a pattern of single spin memory donor atoms in a semiconductor layer, forming a plurality of quantum dots arranged with the semiconductor layer and aligned with the donor atoms, applying a first voltage across at least one aligned pair of a quantum dot and donor atom to control a donor-quantum dot coupling, and applying a second voltage between one or more quantum dots to control a Heisenberg exchange J coupling between quantum dots and to cause transport of a single spin polarized electron between quantum dots.
Measurement-only verifiable blind quantum computing with quantum input verification
NASA Astrophysics Data System (ADS)
Morimae, Tomoyuki
2016-10-01
Verifiable blind quantum computing is a secure delegated quantum computing where a client with a limited quantum technology delegates her quantum computing to a server who has a universal quantum computer. The client's privacy is protected (blindness), and the correctness of the computation is verifiable by the client despite her limited quantum technology (verifiability). There are mainly two types of protocols for verifiable blind quantum computing: the protocol where the client has only to generate single-qubit states and the protocol where the client needs only the ability of single-qubit measurements. The latter is called the measurement-only verifiable blind quantum computing. If the input of the client's quantum computing is a quantum state, whose classical efficient description is not known to the client, there was no way for the measurement-only client to verify the correctness of the input. Here we introduce a protocol of measurement-only verifiable blind quantum computing where the correctness of the quantum input is also verifiable.
Shu, Hua; Lu, Juming; Zhang, Puhong; Zhu, Dongshan; Li, Xian; Ji, Jiachao; Zhao, Fang; Ji, Linong
2018-05-01
We aimed to determine the clinical characteristics of type 2 diabetes patients on basal insulin therapy with inadequate glucose control due to discordance between glycated haemoglobin (HbA 1c ) and fasting plasma glucose (FPG) in the real world. This was a retrospective analysis of data from the ORBIT study in China. Clinical characteristics of patients with discordance between HbA 1c and FPG at baseline and at the end of 6 months of follow-up were analysed using multinomial logistic regression in 4 study groups divided by HbA 1c and FPG. Overall, of 6721 patients initiated on basal insulin, 853 achieved HbA 1c < 7% but FPG ≥ 7 mmol/L (group 2), while 997 had FPG < 7 mmol/L but HbA 1c ≥ 7% (group 3) at the end of follow-up. Patients in group 3 had a longer duration of type 2 diabetes compared with those in group 2 (7.22 ± 5.30 vs 6.00 ± 4.80 y, P < .05). Patients on glargine (32.90%) or detemir (36.88%) treatment accounted for a higher proportion of patients with both HbA 1c and FPG controlled than those on neutral protamine Hagedorn therapy (23.45%; P < .05). Per the multinomial logistic analysis, higher frequency of self-monitoring of blood glucose (SMBG) and use of glargine or detemir therapy were significantly inversely associated with risk of discordance between HbA 1c and FPG, while dose of insulin was a risk factor for discordance at the end of follow-up (all P < .05). Patients treated with insulin analogues (glargine or detemir), instead of neutral protamine Hagedorn, and with more frequent SMBG are more likely to exhibit concordance between HbA 1c and FPG. Copyright © 2018 John Wiley & Sons, Ltd.
Quantum-to-classical crossover near quantum critical point
Vasin, M.; Ryzhov, V.; Vinokur, V. M.
2015-12-21
A quantum phase transition (QPT) is an inherently dynamic phenomenon. However, while non-dissipative quantum dynamics is described in detail, the question, that is not thoroughly understood is how the omnipresent dissipative processes enter the critical dynamics near a quantum critical point (QCP). Here we report a general approach enabling inclusion of both adiabatic and dissipative processes into the critical dynamics on the same footing. We reveal three distinct critical modes, the adiabatic quantum mode (AQM), the dissipative classical mode [classical critical dynamics mode (CCDM)], and the dissipative quantum critical mode (DQCM). We find that as a result of the transitionmore » from the regime dominated by thermal fluctuations to that governed by the quantum ones, the system acquires effective dimension d+zΛ(T), where z is the dynamical exponent, and temperature-depending parameter Λ(T)ε[0, 1] decreases with the temperature such that Λ(T=0) = 1 and Λ(T →∞) = 0. Lastly, our findings lead to a unified picture of quantum critical phenomena including both dissipation- and dissipationless quantum dynamic effects and offer a quantitative description of the quantum-to-classical crossover.« less
Quantum Steganography and Quantum Error-Correction
ERIC Educational Resources Information Center
Shaw, Bilal A.
2010-01-01
Quantum error-correcting codes have been the cornerstone of research in quantum information science (QIS) for more than a decade. Without their conception, quantum computers would be a footnote in the history of science. When researchers embraced the idea that we live in a world where the effects of a noisy environment cannot completely be…
NASA Astrophysics Data System (ADS)
Lidar, Daniel A.; Brun, Todd A.
2013-09-01
Prologue; Preface; Part I. Background: 1. Introduction to decoherence and noise in open quantum systems Daniel Lidar and Todd Brun; 2. Introduction to quantum error correction Dave Bacon; 3. Introduction to decoherence-free subspaces and noiseless subsystems Daniel Lidar; 4. Introduction to quantum dynamical decoupling Lorenza Viola; 5. Introduction to quantum fault tolerance Panos Aliferis; Part II. Generalized Approaches to Quantum Error Correction: 6. Operator quantum error correction David Kribs and David Poulin; 7. Entanglement-assisted quantum error-correcting codes Todd Brun and Min-Hsiu Hsieh; 8. Continuous-time quantum error correction Ognyan Oreshkov; Part III. Advanced Quantum Codes: 9. Quantum convolutional codes Mark Wilde; 10. Non-additive quantum codes Markus Grassl and Martin Rötteler; 11. Iterative quantum coding systems David Poulin; 12. Algebraic quantum coding theory Andreas Klappenecker; 13. Optimization-based quantum error correction Andrew Fletcher; Part IV. Advanced Dynamical Decoupling: 14. High order dynamical decoupling Zhen-Yu Wang and Ren-Bao Liu; 15. Combinatorial approaches to dynamical decoupling Martin Rötteler and Pawel Wocjan; Part V. Alternative Quantum Computation Approaches: 16. Holonomic quantum computation Paolo Zanardi; 17. Fault tolerance for holonomic quantum computation Ognyan Oreshkov, Todd Brun and Daniel Lidar; 18. Fault tolerant measurement-based quantum computing Debbie Leung; Part VI. Topological Methods: 19. Topological codes Héctor Bombín; 20. Fault tolerant topological cluster state quantum computing Austin Fowler and Kovid Goyal; Part VII. Applications and Implementations: 21. Experimental quantum error correction Dave Bacon; 22. Experimental dynamical decoupling Lorenza Viola; 23. Architectures Jacob Taylor; 24. Error correction in quantum communication Mark Wilde; Part VIII. Critical Evaluation of Fault Tolerance: 25. Hamiltonian methods in QEC and fault tolerance Eduardo Novais, Eduardo Mucciolo and
Free-Space Quantum Communication with a Portable Quantum Memory
NASA Astrophysics Data System (ADS)
Namazi, Mehdi; Vallone, Giuseppe; Jordaan, Bertus; Goham, Connor; Shahrokhshahi, Reihaneh; Villoresi, Paolo; Figueroa, Eden
2017-12-01
The realization of an elementary quantum network that is intrinsically secure and operates over long distances requires the interconnection of several quantum modules performing different tasks. In this work, we report the realization of a communication network functioning in a quantum regime, consisting of four different quantum modules: (i) a random polarization qubit generator, (ii) a free-space quantum-communication channel, (iii) an ultralow-noise portable quantum memory, and (iv) a qubit decoder, in a functional elementary quantum network possessing all capabilities needed for quantum-information distribution protocols. We create weak coherent pulses at the single-photon level encoding polarization states |H ⟩ , |V ⟩, |D ⟩, and |A ⟩ in a randomized sequence. The random qubits are sent over a free-space link and coupled into a dual-rail room-temperature quantum memory and after storage and retrieval are analyzed in a four-detector polarization analysis akin to the requirements of the BB84 protocol. We also show ultralow noise and fully portable operation, paving the way towards memory-assisted all-environment free-space quantum cryptographic networks.
Nonequilibrium quantum mechanics: A "hot quantum soup" of paramagnons
NASA Astrophysics Data System (ADS)
Scammell, H. D.; Sushkov, O. P.
2017-01-01
Motivated by recent measurements of the lifetime (decay width) of paramagnons in quantum antiferromagnet TlCuCl3, we investigate paramagnon decay in a heat bath and formulate an appropriate quantum theory. Our formulation can be split into two regimes: (i) a nonperturbative, "hot quantum soup" regime where the paramagnon width is comparable to its energy; (ii) a usual perturbative regime where the paramagnon width is significantly lower than its energy. Close to the Neel temperature, the paramagnon width becomes comparable to its energy and falls into the hot quantum soup regime. To describe this regime, we develop a new finite frequency, finite temperature technique for a nonlinear quantum field theory; the "golden rule of quantum kinetics." The formulation is generic and applicable to any three-dimensional quantum antiferromagnet in the vicinity of a quantum critical point. Specifically, we apply our results to TlCuCl3 and find agreement with experimental data. Additionally, we show that logarithmic running of the coupling constant in the upper critical dimension changes the commonly accepted picture of the quantum disordered and quantum critical regimes.
Open Quantum Walks and Dissipative Quantum Computing
NASA Astrophysics Data System (ADS)
Petruccione, Francesco
2012-02-01
Open Quantum Walks (OQWs) have been recently introduced as quantum Markov chains on graphs [S. Attal, F. Petruccione, C. Sabot, and I. Sinayskiy, E-print: http://hal.archives-ouvertes.fr/hal-00581553/fr/]. The formulation of the OQWs is exclusively based upon the non-unitary dynamics induced by the environment. It will be shown that OQWs are a very useful tool for the formulation of dissipative quantum computing and quantum state preparation. In particular, it will be shown how to implement single qubit gates and the CNOT gate as OQWs on fully connected graphs. Also, OQWS make possible the dissipative quantum state preparation of arbitrary single qubit states and of all two-qubit Bell states. Finally, it will be shown how to reformulate efficiently a discrete time version of dissipative quantum computing in the language of OQWs.
Relativistic quantum metrology: exploiting relativity to improve quantum measurement technologies.
Ahmadi, Mehdi; Bruschi, David Edward; Sabín, Carlos; Adesso, Gerardo; Fuentes, Ivette
2014-05-22
We present a framework for relativistic quantum metrology that is useful for both Earth-based and space-based technologies. Quantum metrology has been so far successfully applied to design precision instruments such as clocks and sensors which outperform classical devices by exploiting quantum properties. There are advanced plans to implement these and other quantum technologies in space, for instance Space-QUEST and Space Optical Clock projects intend to implement quantum communications and quantum clocks at regimes where relativity starts to kick in. However, typical setups do not take into account the effects of relativity on quantum properties. To include and exploit these effects, we introduce techniques for the application of metrology to quantum field theory. Quantum field theory properly incorporates quantum theory and relativity, in particular, at regimes where space-based experiments take place. This framework allows for high precision estimation of parameters that appear in quantum field theory including proper times and accelerations. Indeed, the techniques can be applied to develop a novel generation of relativistic quantum technologies for gravimeters, clocks and sensors. As an example, we present a high precision device which in principle improves the state-of-the-art in quantum accelerometers by exploiting relativistic effects.
NASA Astrophysics Data System (ADS)
Aharonov, Dorit
In the last few years, theoretical study of quantum systems serving as computational devices has achieved tremendous progress. We now have strong theoretical evidence that quantum computers, if built, might be used as a dramatically powerful computational tool, capable of performing tasks which seem intractable for classical computers. This review is about to tell the story of theoretical quantum computation. I l out the developing topic of experimental realizations of the model, and neglected other closely related topics which are quantum information and quantum communication. As a result of narrowing the scope of this paper, I hope it has gained the benefit of being an almost self contained introduction to the exciting field of quantum computation. The review begins with background on theoretical computer science, Turing machines and Boolean circuits. In light of these models, I define quantum computers, and discuss the issue of universal quantum gates. Quantum algorithms, including Shor's factorization algorithm and Grover's algorithm for searching databases, are explained. I will devote much attention to understanding what the origins of the quantum computational power are, and what the limits of this power are. Finally, I describe the recent theoretical results which show that quantum computers maintain their complexity power even in the presence of noise, inaccuracies and finite precision. This question cannot be separated from that of quantum complexity because any realistic model will inevitably be subjected to such inaccuracies. I tried to put all results in their context, asking what the implications to other issues in computer science and physics are. In the end of this review, I make these connections explicit by discussing the possible implications of quantum computation on fundamental physical questions such as the transition from quantum to classical physics.
Hybrid Quantum-Classical Approach to Quantum Optimal Control.
Li, Jun; Yang, Xiaodong; Peng, Xinhua; Sun, Chang-Pu
2017-04-14
A central challenge in quantum computing is to identify more computational problems for which utilization of quantum resources can offer significant speedup. Here, we propose a hybrid quantum-classical scheme to tackle the quantum optimal control problem. We show that the most computationally demanding part of gradient-based algorithms, namely, computing the fitness function and its gradient for a control input, can be accomplished by the process of evolution and measurement on a quantum simulator. By posing queries to and receiving answers from the quantum simulator, classical computing devices update the control parameters until an optimal control solution is found. To demonstrate the quantum-classical scheme in experiment, we use a seven-qubit nuclear magnetic resonance system, on which we have succeeded in optimizing state preparation without involving classical computation of the large Hilbert space evolution.
Quantum Speed Limits across the Quantum-to-Classical Transition
NASA Astrophysics Data System (ADS)
Shanahan, B.; Chenu, A.; Margolus, N.; del Campo, A.
2018-02-01
Quantum speed limits set an upper bound to the rate at which a quantum system can evolve. Adopting a phase-space approach, we explore quantum speed limits across the quantum-to-classical transition and identify equivalent bounds in the classical world. As a result, and contrary to common belief, we show that speed limits exist for both quantum and classical systems. As in the quantum domain, classical speed limits are set by a given norm of the generator of time evolution.
High-dimensional quantum cloning and applications to quantum hacking
Bouchard, Frédéric; Fickler, Robert; Boyd, Robert W.; Karimi, Ebrahim
2017-01-01
Attempts at cloning a quantum system result in the introduction of imperfections in the state of the copies. This is a consequence of the no-cloning theorem, which is a fundamental law of quantum physics and the backbone of security for quantum communications. Although perfect copies are prohibited, a quantum state may be copied with maximal accuracy via various optimal cloning schemes. Optimal quantum cloning, which lies at the border of the physical limit imposed by the no-signaling theorem and the Heisenberg uncertainty principle, has been experimentally realized for low-dimensional photonic states. However, an increase in the dimensionality of quantum systems is greatly beneficial to quantum computation and communication protocols. Nonetheless, no experimental demonstration of optimal cloning machines has hitherto been shown for high-dimensional quantum systems. We perform optimal cloning of high-dimensional photonic states by means of the symmetrization method. We show the universality of our technique by conducting cloning of numerous arbitrary input states and fully characterize our cloning machine by performing quantum state tomography on cloned photons. In addition, a cloning attack on a Bennett and Brassard (BB84) quantum key distribution protocol is experimentally demonstrated to reveal the robustness of high-dimensional states in quantum cryptography. PMID:28168219
Quantum secret sharing for a general quantum access structure
NASA Astrophysics Data System (ADS)
Bai, Chen-Ming; Li, Zhi-Hui; Si, Meng-Meng; Li, Yong-Ming
2017-10-01
Quantum secret sharing is a procedure for sharing a secret among a number of participants such that only certain subsets of participants can collaboratively reconstruct it, which are called authorized sets. The quantum access structure of a secret sharing is a family of all authorized sets. Firstly, in this paper, we propose the concept of decomposition of quantum access structure to design a quantum secret sharing scheme. Secondly, based on a maximal quantum access structure (MQAS) [D. Gottesman, Phys. Rev. A 61, 042311 (2000)], we propose an algorithm to improve a MQAS and obtain an improved maximal quantum access structure (IMQAS). Then, we present a sufficient and necessary condition about IMQAS, which shows the relationship between the minimal authorized sets and the players. In accordance with properties, we construct an efficient quantum secret sharing scheme with a decomposition and IMQAS. A major advantage of these techniques is that it allows us to construct a method to realize a general quantum access structure. Finally, we present two kinds of quantum secret sharing schemes via the thought of concatenation or a decomposition of quantum access structure. As a consequence, we find that the application of these techniques allows us to save more quantum shares and reduces more cost than the existing scheme.
High-dimensional quantum cloning and applications to quantum hacking.
Bouchard, Frédéric; Fickler, Robert; Boyd, Robert W; Karimi, Ebrahim
2017-02-01
Attempts at cloning a quantum system result in the introduction of imperfections in the state of the copies. This is a consequence of the no-cloning theorem, which is a fundamental law of quantum physics and the backbone of security for quantum communications. Although perfect copies are prohibited, a quantum state may be copied with maximal accuracy via various optimal cloning schemes. Optimal quantum cloning, which lies at the border of the physical limit imposed by the no-signaling theorem and the Heisenberg uncertainty principle, has been experimentally realized for low-dimensional photonic states. However, an increase in the dimensionality of quantum systems is greatly beneficial to quantum computation and communication protocols. Nonetheless, no experimental demonstration of optimal cloning machines has hitherto been shown for high-dimensional quantum systems. We perform optimal cloning of high-dimensional photonic states by means of the symmetrization method. We show the universality of our technique by conducting cloning of numerous arbitrary input states and fully characterize our cloning machine by performing quantum state tomography on cloned photons. In addition, a cloning attack on a Bennett and Brassard (BB84) quantum key distribution protocol is experimentally demonstrated to reveal the robustness of high-dimensional states in quantum cryptography.
Computational quantum-classical boundary of noisy commuting quantum circuits
Fujii, Keisuke; Tamate, Shuhei
2016-01-01
It is often said that the transition from quantum to classical worlds is caused by decoherence originated from an interaction between a system of interest and its surrounding environment. Here we establish a computational quantum-classical boundary from the viewpoint of classical simulatability of a quantum system under decoherence. Specifically, we consider commuting quantum circuits being subject to decoherence. Or equivalently, we can regard them as measurement-based quantum computation on decohered weighted graph states. To show intractability of classical simulation in the quantum side, we utilize the postselection argument and crucially strengthen it by taking noise effect into account. Classical simulatability in the classical side is also shown constructively by using both separable criteria in a projected-entangled-pair-state picture and the Gottesman-Knill theorem for mixed state Clifford circuits. We found that when each qubit is subject to a single-qubit complete-positive-trace-preserving noise, the computational quantum-classical boundary is sharply given by the noise rate required for the distillability of a magic state. The obtained quantum-classical boundary of noisy quantum dynamics reveals a complexity landscape of controlled quantum systems. This paves a way to an experimentally feasible verification of quantum mechanics in a high complexity limit beyond classically simulatable region. PMID:27189039
Computational quantum-classical boundary of noisy commuting quantum circuits.
Fujii, Keisuke; Tamate, Shuhei
2016-05-18
It is often said that the transition from quantum to classical worlds is caused by decoherence originated from an interaction between a system of interest and its surrounding environment. Here we establish a computational quantum-classical boundary from the viewpoint of classical simulatability of a quantum system under decoherence. Specifically, we consider commuting quantum circuits being subject to decoherence. Or equivalently, we can regard them as measurement-based quantum computation on decohered weighted graph states. To show intractability of classical simulation in the quantum side, we utilize the postselection argument and crucially strengthen it by taking noise effect into account. Classical simulatability in the classical side is also shown constructively by using both separable criteria in a projected-entangled-pair-state picture and the Gottesman-Knill theorem for mixed state Clifford circuits. We found that when each qubit is subject to a single-qubit complete-positive-trace-preserving noise, the computational quantum-classical boundary is sharply given by the noise rate required for the distillability of a magic state. The obtained quantum-classical boundary of noisy quantum dynamics reveals a complexity landscape of controlled quantum systems. This paves a way to an experimentally feasible verification of quantum mechanics in a high complexity limit beyond classically simulatable region.
Computational quantum-classical boundary of noisy commuting quantum circuits
NASA Astrophysics Data System (ADS)
Fujii, Keisuke; Tamate, Shuhei
2016-05-01
It is often said that the transition from quantum to classical worlds is caused by decoherence originated from an interaction between a system of interest and its surrounding environment. Here we establish a computational quantum-classical boundary from the viewpoint of classical simulatability of a quantum system under decoherence. Specifically, we consider commuting quantum circuits being subject to decoherence. Or equivalently, we can regard them as measurement-based quantum computation on decohered weighted graph states. To show intractability of classical simulation in the quantum side, we utilize the postselection argument and crucially strengthen it by taking noise effect into account. Classical simulatability in the classical side is also shown constructively by using both separable criteria in a projected-entangled-pair-state picture and the Gottesman-Knill theorem for mixed state Clifford circuits. We found that when each qubit is subject to a single-qubit complete-positive-trace-preserving noise, the computational quantum-classical boundary is sharply given by the noise rate required for the distillability of a magic state. The obtained quantum-classical boundary of noisy quantum dynamics reveals a complexity landscape of controlled quantum systems. This paves a way to an experimentally feasible verification of quantum mechanics in a high complexity limit beyond classically simulatable region.
Quantum Error Correction Protects Quantum Search Algorithms Against Decoherence
Botsinis, Panagiotis; Babar, Zunaira; Alanis, Dimitrios; Chandra, Daryus; Nguyen, Hung; Ng, Soon Xin; Hanzo, Lajos
2016-01-01
When quantum computing becomes a wide-spread commercial reality, Quantum Search Algorithms (QSA) and especially Grover’s QSA will inevitably be one of their main applications, constituting their cornerstone. Most of the literature assumes that the quantum circuits are free from decoherence. Practically, decoherence will remain unavoidable as is the Gaussian noise of classic circuits imposed by the Brownian motion of electrons, hence it may have to be mitigated. In this contribution, we investigate the effect of quantum noise on the performance of QSAs, in terms of their success probability as a function of the database size to be searched, when decoherence is modelled by depolarizing channels’ deleterious effects imposed on the quantum gates. Moreover, we employ quantum error correction codes for limiting the effects of quantum noise and for correcting quantum flips. More specifically, we demonstrate that, when we search for a single solution in a database having 4096 entries using Grover’s QSA at an aggressive depolarizing probability of 10−3, the success probability of the search is 0.22 when no quantum coding is used, which is improved to 0.96 when Steane’s quantum error correction code is employed. Finally, apart from Steane’s code, the employment of Quantum Bose-Chaudhuri-Hocquenghem (QBCH) codes is also considered. PMID:27924865
Quantum Optical Implementations of Quantum Computing and Quantum Informatics Protocols
2007-11-20
4, 2005. ) 14. M. 0. Scully, "The EPR Paradox Revisted", AMO Physics Seminar, TAMU Jan. 18, 2005. 15. M. S. Zubairy, "Quantum computing: Cavity QED...the EPR dispersion relation and the average photon number. We have shown that atomic coherence is the key to the development of such a laser. In...PRISM-TAMU Symposium on Quantum Material Science, Princeton University, February 21-22, 2005. ) 21. M. 0. Scully, "From EPR to quantum eraser: The Role
Quantum mechanics on the h-deformed quantum plane
NASA Astrophysics Data System (ADS)
Cho, Sunggoo
1999-03-01
We find the covariant deformed Heisenberg algebra and the Laplace-Beltrami operator on the extended h-deformed quantum plane and solve the Schrödinger equations explicitly for some physical systems on the quantum plane. In the commutative limit the behaviour of a quantum particle on the quantum plane becomes that of the quantum particle on the Poincaré half-plane, a surface of constant negative Gaussian curvature. We show that the bound state energy spectra for particles under specific potentials depend explicitly on the deformation parameter h. Moreover, it is shown that bound states can survive on the quantum plane in a limiting case where bound states on the Poincaré half-plane disappear.
U-Th-Pb age of the Barwell chondrite - Anatomy of a 'discordant' meteorite
NASA Technical Reports Server (NTRS)
Unruh, D. M.; Tatsumoto, M.; Hutchison, R.
1979-01-01
A Pb-Pb internal isochron for the Barwell L5-6 chondrite yields an age of 4.530 plus or minus 0.005 billion years, using the measured U-238/U-235 ratio of 135.24 plus or minus .17. If the terrestrial U isotope composition is used, an age of 4.559 billion years is obtained. The Pb isotopic composition is distinctly different from that of a terrestrial contaminant found in the fusion crust of the Barwell stone. When the U-Th-Pb data are plotted on the concordia diagram, the data define a line that intersects the concordia curve at approximately 4.53 and 0 billion years, and nearly all of the data plot above the concordia curve, regardless of the initial Pb correction. This discordancy and the Pb isotopic composition of the triolite are attributed to a recent reequilibration of Pb and not to terrestrial contamination.
Relativistic Quantum Metrology: Exploiting relativity to improve quantum measurement technologies
Ahmadi, Mehdi; Bruschi, David Edward; Sabín, Carlos; Adesso, Gerardo; Fuentes, Ivette
2014-01-01
We present a framework for relativistic quantum metrology that is useful for both Earth-based and space-based technologies. Quantum metrology has been so far successfully applied to design precision instruments such as clocks and sensors which outperform classical devices by exploiting quantum properties. There are advanced plans to implement these and other quantum technologies in space, for instance Space-QUEST and Space Optical Clock projects intend to implement quantum communications and quantum clocks at regimes where relativity starts to kick in. However, typical setups do not take into account the effects of relativity on quantum properties. To include and exploit these effects, we introduce techniques for the application of metrology to quantum field theory. Quantum field theory properly incorporates quantum theory and relativity, in particular, at regimes where space-based experiments take place. This framework allows for high precision estimation of parameters that appear in quantum field theory including proper times and accelerations. Indeed, the techniques can be applied to develop a novel generation of relativistic quantum technologies for gravimeters, clocks and sensors. As an example, we present a high precision device which in principle improves the state-of-the-art in quantum accelerometers by exploiting relativistic effects. PMID:24851858
NASA Astrophysics Data System (ADS)
Coecke, Bob; Kissinger, Aleks
2017-03-01
Preface; 1. Introduction; 2. Guide to reading this textbook; 3. Processes as diagrams; 4. String diagrams; 5. Hilbert space from diagrams; 6. Quantum processes; 7. Quantum measurement; 8. Picturing classical-quantum processes; 9. Picturing phases and complementarity; 10. Quantum theory: the full picture; 11. Quantum foundations; 12. Quantum computation; 13. Quantum resources; 14. Quantomatic; Appendix A. Some notations; References; Index.
Limited Quantum Helium Transportation through Nano-channels by Quantum Fluctuation
Ohba, Tomonori
2016-01-01
Helium at low temperatures has unique quantum properties such as superfluidity, which causes it to behave differently from a classical fluid. Despite our deep understanding of quantum mechanics, there are many open questions concerning the properties of quantum fluids in nanoscale systems. Herein, the quantum behavior of helium transportation through one-dimensional nanopores was evaluated by measuring the adsorption of quantum helium in the nanopores of single-walled carbon nanohorns and AlPO4-5 at 2–5 K. Quantum helium was transported unimpeded through nanopores larger than 0.7 nm in diameter, whereas quantum helium transportation was significantly restricted through 0.4-nm and 0.6-nm nanopores. Conversely, nitrogen molecules diffused through the 0.4-nm nanopores at 77 K. Therefore, quantum helium behaved as a fluid comprising atoms larger than 0.4–0.6 nm. This phenomenon was remarkable, considering that helium is the smallest existing element with a (classical) size of approximately 0.27 nm. This finding revealed the presence of significant quantum fluctuations. Quantum fluctuation determined the behaviors of quantum flux and is essential to understanding unique quantum behaviors in nanoscale systems. PMID:27363671
Simulation of n-qubit quantum systems. I. Quantum registers and quantum gates
NASA Astrophysics Data System (ADS)
Radtke, T.; Fritzsche, S.
2005-12-01
During recent years, quantum computations and the study of n-qubit quantum systems have attracted a lot of interest, both in theory and experiment. Apart from the promise of performing quantum computations, however, these investigations also revealed a great deal of difficulties which still need to be solved in practice. In quantum computing, unitary and non-unitary quantum operations act on a given set of qubits to form (entangled) states, in which the information is encoded by the overall system often referred to as quantum registers. To facilitate the simulation of such n-qubit quantum systems, we present the FEYNMAN program to provide all necessary tools in order to define and to deal with quantum registers and quantum operations. Although the present version of the program is restricted to unitary transformations, it equally supports—whenever possible—the representation of the quantum registers both, in terms of their state vectors and density matrices. In addition to the composition of two or more quantum registers, moreover, the program also supports their decomposition into various parts by applying the partial trace operation and the concept of the reduced density matrix. Using an interactive design within the framework of MAPLE, therefore, we expect the FEYNMAN program to be helpful not only for teaching the basic elements of quantum computing but also for studying their physical realization in the future. Program summaryTitle of program:FEYNMAN Catalogue number:ADWE Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADWE Program obtainable from:CPC Program Library, Queen's University of Belfast, N. Ireland Licensing provisions:None Computers for which the program is designed:All computers with a license of the computer algebra system MAPLE [Maple is a registered trademark of Waterlo Maple Inc.] Operating systems or monitors under which the program has been tested:Linux, MS Windows XP Programming language used:MAPLE 9.5 (but should be compatible
Multi-party Semi-quantum Key Agreement with Delegating Quantum Computation
NASA Astrophysics Data System (ADS)
Liu, Wen-Jie; Chen, Zhen-Yu; Ji, Sai; Wang, Hai-Bin; Zhang, Jun
2017-10-01
A multi-party semi-quantum key agreement (SQKA) protocol based on delegating quantum computation (DQC) model is proposed by taking Bell states as quantum resources. In the proposed protocol, the participants only need the ability of accessing quantum channel and preparing single photons {|0〉, |1〉, |+〉, |-〉}, while the complicated quantum operations, such as the unitary operations and Bell measurement, will be delegated to the remote quantum center. Compared with previous quantum key agreement protocols, this client-server model is more feasible in the early days of the emergence of quantum computers. In order to prevent the attacks from outside eavesdroppers, inner participants and quantum center, two single photon sequences are randomly inserted into Bell states: the first sequence is used to perform the quantum channel detection, while the second is applied to disorder the positions of message qubits, which guarantees the security of the protocol.
Observing single quantum trajectories of a superconducting quantum bit
NASA Astrophysics Data System (ADS)
Murch, K. W.; Weber, S. J.; Macklin, C.; Siddiqi, I.
2013-10-01
The length of time that a quantum system can exist in a superposition state is determined by how strongly it interacts with its environment. This interaction entangles the quantum state with the inherent fluctuations of the environment. If these fluctuations are not measured, the environment can be viewed as a source of noise, causing random evolution of the quantum system from an initially pure state into a statistical mixture--a process known as decoherence. However, by accurately measuring the environment in real time, the quantum system can be maintained in a pure state and its time evolution described by a `quantum trajectory' determined by the measurement outcome. Here we use weak measurements to monitor a microwave cavity containing a superconducting quantum bit (qubit), and track the individual quantum trajectories of the system. In this set-up, the environment is dominated by the fluctuations of a single electromagnetic mode of the cavity. Using a near-quantum-limited parametric amplifier, we selectively measure either the phase or the amplitude of the cavity field, and thereby confine trajectories to either the equator or a meridian of the Bloch sphere. We perform quantum state tomography at discrete times along the trajectory to verify that we have faithfully tracked the state of the quantum system as it diffuses on the surface of the Bloch sphere. Our results demonstrate that decoherence can be mitigated by environmental monitoring, and validate the foundation of quantum feedback approaches based on Bayesian statistics. Moreover, our experiments suggest a new means of implementing `quantum steering'--the harnessing of action at a distance to manipulate quantum states through measurement.
Observing single quantum trajectories of a superconducting quantum bit.
Murch, K W; Weber, S J; Macklin, C; Siddiqi, I
2013-10-10
The length of time that a quantum system can exist in a superposition state is determined by how strongly it interacts with its environment. This interaction entangles the quantum state with the inherent fluctuations of the environment. If these fluctuations are not measured, the environment can be viewed as a source of noise, causing random evolution of the quantum system from an initially pure state into a statistical mixture--a process known as decoherence. However, by accurately measuring the environment in real time, the quantum system can be maintained in a pure state and its time evolution described by a 'quantum trajectory' determined by the measurement outcome. Here we use weak measurements to monitor a microwave cavity containing a superconducting quantum bit (qubit), and track the individual quantum trajectories of the system. In this set-up, the environment is dominated by the fluctuations of a single electromagnetic mode of the cavity. Using a near-quantum-limited parametric amplifier, we selectively measure either the phase or the amplitude of the cavity field, and thereby confine trajectories to either the equator or a meridian of the Bloch sphere. We perform quantum state tomography at discrete times along the trajectory to verify that we have faithfully tracked the state of the quantum system as it diffuses on the surface of the Bloch sphere. Our results demonstrate that decoherence can be mitigated by environmental monitoring, and validate the foundation of quantum feedback approaches based on Bayesian statistics. Moreover, our experiments suggest a new means of implementing 'quantum steering'--the harnessing of action at a distance to manipulate quantum states through measurement.
Quantum Plasmonics: Quantum Information at the Nanoscale
2016-11-06
journal. In total this project has thus far resulted in six journal articles. We are currently writing up an additional work, on direct quantum tomography...resulted in six journal articles. We are currently writing up an additional work, on direct quantum tomography on state entanglement in quantum
Two-time quantum transport and quantum diffusion.
Kleinert, P
2009-05-01
Based on the nonequilibrium Green's function technique, a unified theory is developed that covers quantum transport and quantum diffusion in bulk semiconductors on the same footing. This approach, which is applicable to transport via extended and localized states, extends previous semiphenomenological studies and puts them on a firm microscopic basis. The approach is sufficiently general and applies not only to well-studied quantum-transport problems, but also to models, in which the Hamiltonian does not commute with the dipole operator. It is shown that even for the unified treatment of quantum transport and quantum diffusion in homogeneous systems, all quasimomenta of the carrier distribution function are present and fulfill their specific function. Particular emphasis is put on the double-time nature of quantum kinetics. To demonstrate the existence of robust macroscopic transport effects that have a true double-time character, a phononless steady-state current is identified that appears only beyond the generalized Kadanoff-Baym ansatz.
Pfeiffer, P.; Egusquiza, I. L.; Di Ventra, M.; ...
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
Andres, Allen M; Kooren, Joel A; Parker, Sarah J; Tucker, Kyle C; Ravindran, Nandini; Ito, Bruce R; Huang, Chengqun; Venkatraman, Vidya; Van Eyk, Jennifer E; Gottlieb, Roberta A; Mentzer, Robert M
2016-07-01
Autophagy is regulated by nutrient and energy status and plays an adaptive role during nutrient deprivation and ischemic stress. Metabolic syndrome (MetS) is a hypernutritive state characterized by obesity, dyslipidemia, elevated fasting blood glucose levels, and insulin resistance. It has also been associated with impaired autophagic flux and larger-sized infarcts. We hypothesized that diet-induced obesity (DIO) affects nutrient sensing, explaining the observed cardiac impaired autophagy. We subjected male friend virus B NIH (FVBN) mice to a high-fat diet, which resulted in increased weight gain, fat deposition, hyperglycemia, insulin resistance, and larger infarcts after myocardial ischemia-reperfusion. Autophagic flux was impaired after 4 wk on a high-fat diet. To interrogate nutrient-sensing pathways, DIO mice were subjected to overnight fasting, and hearts were processed for biochemical and proteomic analysis. Obese mice failed to upregulate LC3-II or to clear p62/SQSTM1 after fasting, although mRNA for LC3B and p62/SQSTM1 were appropriately upregulated in both groups, demonstrating an intact transcriptional response to fasting. Energy- and nutrient-sensing signal transduction pathways [AMPK and mammalian target of rapamycin (mTOR)] also responded appropriately to fasting, although mTOR was more profoundly suppressed in obese mice. Proteomic quantitative analysis of the hearts under fed and fasted conditions revealed broad changes in protein networks involved in oxidative phosphorylation, autophagy, oxidative stress, protein homeostasis, and contractile machinery. In many instances, the fasting response was quite discordant between lean and DIO mice. Network analysis implicated the peroxisome proliferator-activated receptor and mTOR regulatory nodes. Hearts of obese mice exhibited impaired autophagy, altered proteome, and discordant response to nutrient deprivation. Copyright © 2016 the American Physiological Society.
Quantum Entanglement of Quantum Dot Spin Using Flying Qubits
2015-05-01
QUANTUM ENTANGLEMENT OF QUANTUM DOT SPIN USING FLYING QUBITS UNIVERSITY OF MICHIGAN MAY 2015 FINAL TECHNICAL REPORT APPROVED FOR PUBLIC RELEASE...To) SEP 2012 – DEC 2014 4. TITLE AND SUBTITLE QUANTUM ENTANGLEMENT OF QUANTUM DOT SPIN USING FLYING QUBITS 5a. CONTRACT NUMBER FA8750-12-2-0333...been to advance the frontier of quantum entangled semiconductor electrons using ultrafast optical techniques. The approach is based on
Playing distributed two-party quantum games on quantum networks
NASA Astrophysics Data System (ADS)
Liu, Bo-Yang; Dai, Hong-Yi; Zhang, Ming
2017-12-01
This paper investigates quantum games between two remote players on quantum networks. We propose two schemes for distributed remote quantum games: the client-server scheme based on states transmission between nodes of the network and the peer-to-peer scheme devised upon remote quantum operations. Following these schemes, we construct two designs of the distributed prisoners' dilemma game on quantum entangling networks, where concrete methods are employed for teleportation and nonlocal two-qubits unitary gates, respectively. It seems to us that the requirement for playing distributed quantum games on networks is still an open problem. We explore this problem by comparing and characterizing the two schemes from the viewpoints of network structures, quantum and classical operations, experimental realization and simplification.
Quantum-Enhanced Cyber Security: Experimental Computation on Quantum-Encrypted Data
2017-03-02
AFRL-AFOSR-UK-TR-2017-0020 Quantum-Enhanced Cyber Security: Experimental Computation on Quantum-Encrypted Data Philip Walther UNIVERSITT WIEN Final...REPORT TYPE Final 3. DATES COVERED (From - To) 15 Oct 2015 to 31 Dec 2016 4. TITLE AND SUBTITLE Quantum-Enhanced Cyber Security: Experimental Computation...FORM SF 298 Final Report for FA9550-1-6-1-0004 Quantum-enhanced cyber security: Experimental quantum computation with quantum-encrypted data
Uzelac, Ilija; Ji, Yanyan C.; Hornung, Daniel; Schröder-Scheteling, Johannes; Luther, Stefan; Gray, Richard A.; Cherry, Elizabeth M.; Fenton, Flavio H.
2017-01-01
Rationale: Discordant alternans, a phenomenon in which the action potential duration (APDs) and/or intracellular calcium transient durations (CaDs) in different spatial regions of cardiac tissue are out of phase, present a dynamical instability for complex spatial dispersion that can be associated with long-QT syndrome (LQTS) and the initiation of reentrant arrhythmias. Because the use of numerical simulations to investigate arrhythmic effects, such as acquired LQTS by drugs is beginning to be studied by the FDA, it is crucial to validate mathematical models that may be used during this process. Objective: In this study, we characterized with high spatio-temporal resolution the development of discordant alternans patterns in transmembrane voltage (Vm) and intracellular calcium concentration ([Cai]+2) as a function of pacing period in rabbit hearts. Then we compared the dynamics to that of the latest state-of-the-art model for ventricular action potentials and calcium transients to better understand the underlying mechanisms of discordant alternans and compared the experimental data to the mathematical models representing Vm and [Cai]+2 dynamics. Methods and Results: We performed simultaneous dual optical mapping imaging of Vm and [Cai]+2 in Langendorff-perfused rabbit hearts with higher spatial resolutions compared with previous studies. The rabbit hearts developed discordant alternans through decreased pacing period protocols and we quantified the presence of multiple nodal points along the direction of wave propagation, both in APD and CaD, and compared these findings with results from theoretical models. In experiments, the nodal lines of CaD alternans have a steeper slope than those of APD alternans, but not as steep as predicted by numerical simulations in rabbit models. We further quantified several additional discrepancies between models and experiments. Conclusions: Alternans in CaD have nodal lines that are about an order of magnitude steeper compared to
NASA Astrophysics Data System (ADS)
Malpetti, Daniele; Roscilde, Tommaso
2017-02-01
The mean-field approximation is at the heart of our understanding of complex systems, despite its fundamental limitation of completely neglecting correlations between the elementary constituents. In a recent work [Phys. Rev. Lett. 117, 130401 (2016), 10.1103/PhysRevLett.117.130401], we have shown that in quantum many-body systems at finite temperature, two-point correlations can be formally separated into a thermal part and a quantum part and that quantum correlations are generically found to decay exponentially at finite temperature, with a characteristic, temperature-dependent quantum coherence length. The existence of these two different forms of correlation in quantum many-body systems suggests the possibility of formulating an approximation, which affects quantum correlations only, without preventing the correct description of classical fluctuations at all length scales. Focusing on lattice boson and quantum Ising models, we make use of the path-integral formulation of quantum statistical mechanics to introduce such an approximation, which we dub quantum mean-field (QMF) approach, and which can be readily generalized to a cluster form (cluster QMF or cQMF). The cQMF approximation reduces to cluster mean-field theory at T =0 , while at any finite temperature it produces a family of systematically improved, semi-classical approximations to the quantum statistical mechanics of the lattice theory at hand. Contrary to standard MF approximations, the correct nature of thermal critical phenomena is captured by any cluster size. In the two exemplary cases of the two-dimensional quantum Ising model and of two-dimensional quantum rotors, we study systematically the convergence of the cQMF approximation towards the exact result, and show that the convergence is typically linear or sublinear in the boundary-to-bulk ratio of the clusters as T →0 , while it becomes faster than linear as T grows. These results pave the way towards the development of semiclassical numerical
Quantum Optical Implementations of Current Quantum Computing Paradigms
2005-05-01
Conferences and Proceedings: The results were presented at several conferences. These include: 1. M. O. Scully, " Foundations of Quantum Mechanics ", in...applications have revealed a strong connection between the fundamental aspects of quantum mechanics that governs physical systems and the informational...could be solved in polynomial time using quantum computers. Another set of problems where quantum mechanics can carry out computations substantially
A universal quantum information processor for scalable quantum communication and networks
Yang, Xihua; Xue, Bolin; Zhang, Junxiang; Zhu, Shiyao
2014-01-01
Entanglement provides an essential resource for quantum computation, quantum communication, and quantum networks. How to conveniently and efficiently realize the generation, distribution, storage, retrieval, and control of multipartite entanglement is the basic requirement for realistic quantum information processing. Here, we present a theoretical proposal to efficiently and conveniently achieve a universal quantum information processor (QIP) via atomic coherence in an atomic ensemble. The atomic coherence, produced through electromagnetically induced transparency (EIT) in the Λ-type configuration, acts as the QIP and has full functions of quantum beam splitter, quantum frequency converter, quantum entangler, and quantum repeater. By employing EIT-based nondegenerate four-wave mixing processes, the generation, exchange, distribution, and manipulation of light-light, atom-light, and atom-atom multipartite entanglement can be efficiently and flexibly achieved in a deterministic way with only coherent light fields. This method greatly facilitates the operations in quantum information processing, and holds promising applications in realistic scalable quantum communication and quantum networks. PMID:25316514
Quantum amplification and quantum optical tapping with squeezed states and correlated quantum states
NASA Technical Reports Server (NTRS)
Ou, Z. Y.; Pereira, S. F.; Kimble, H. J.
1994-01-01
Quantum fluctuations in a nondegenerate optical parametric amplifier (NOPA) are investigated experimentally with a squeezed state coupled into the internal idler mode of the NOPA. Reductions of the inherent quantum noise of the amplifier are observed with a minimum noise level 0.7 dB below the usual noise level of the amplifier with its idler mode in a vacuum state. With two correlated quantum fields as the amplifier's inputs and proper adjustment of the gain of the amplifier, it is shown that the amplifier's intrinsic quantum noise can be completely suppressed so that noise-free amplification is achieved. It is also shown that the NOPA, when coupled to either a squeezed state or a nonclassically correlated state, can realize quantum tapping of optical information.
Kendon, Vivien M; Nemoto, Kae; Munro, William J
2010-08-13
We briefly review what a quantum computer is, what it promises to do for us and why it is so hard to build one. Among the first applications anticipated to bear fruit is the quantum simulation of quantum systems. While most quantum computation is an extension of classical digital computation, quantum simulation differs fundamentally in how the data are encoded in the quantum computer. To perform a quantum simulation, the Hilbert space of the system to be simulated is mapped directly onto the Hilbert space of the (logical) qubits in the quantum computer. This type of direct correspondence is how data are encoded in a classical analogue computer. There is no binary encoding, and increasing precision becomes exponentially costly: an extra bit of precision doubles the size of the computer. This has important consequences for both the precision and error-correction requirements of quantum simulation, and significant open questions remain about its practicality. It also means that the quantum version of analogue computers, continuous-variable quantum computers, becomes an equally efficient architecture for quantum simulation. Lessons from past use of classical analogue computers can help us to build better quantum simulators in future.
St Romain, Paul; Madan, Rashna; Tawfik, Ossama W; Damjanov, Ivan; Fan, Fang
2012-03-01
Prior studies have suggested that the type of breast cancer influences the location of distant metastases ("organotropism") and that there may be discordance of estrogen receptor and human epidermal growth factor receptor 2 (Her2) expression between primaries and metastases. Our aims were to investigate the relationship between tumor type and metastatic site and to compare biomarker expression between primary and metastatic tumors. We retrospectively reviewed 102 biopsy-proven cases of breast cancer metastatic to distant sites from 2000 to 2010 and 34 corresponding primaries for histologic subtype, grade, lymphovascular invasion, lymph node metastasis, and expression of estrogen receptor and Her2. Most metastases were of ductal (88) and lobular (11) histologic types. Available data on primaries indicated that the majority were grade III with positive lymph node metastasis and lymphovascular invasion. Biomarkers on 73 metastases showed 37 estrogen receptor positive/Her2-, 6 estrogen receptor positive/Her2+, 8 estrogen receptor negative/Her2+, and 22 estrogen receptor negative/Her2-. The most common metastatic sites were the lung (26%), bone (32%), and liver (21%). We found no association between estrogen receptor/Her2 profile and metastatic site (P = .16). When compared with ductal carcinoma, lobular carcinoma showed a unique metastatic pattern to gastrointestinal tract/gynecologic sites (P = .014). Of 34 cases with paired prognostic markers for primary and metastatic sites, 7 (20%) demonstrated discordance in estrogen receptor-positive/Her2 profile between the primary and the metastasis. Because the estrogen receptor-positive/Her2 profile of metastatic breast cancer did not always match that of the primary tumor, it is important to repeat the prognostic markers of metastasis. Copyright © 2012 Elsevier Inc. All rights reserved.
Are Quantum Models for Order Effects Quantum?
NASA Astrophysics Data System (ADS)
Moreira, Catarina; Wichert, Andreas
2017-12-01
The application of principles of Quantum Mechanics in areas outside of physics has been getting increasing attention in the scientific community in an emergent disciplined called Quantum Cognition. These principles have been applied to explain paradoxical situations that cannot be easily explained through classical theory. In quantum probability, events are characterised by a superposition state, which is represented by a state vector in a N-dimensional vector space. The probability of an event is given by the squared magnitude of the projection of this superposition state into the desired subspace. This geometric approach is very useful to explain paradoxical findings that involve order effects, but do we really need quantum principles for models that only involve projections? This work has two main goals. First, it is still not clear in the literature if a quantum projection model has any advantage towards a classical projection. We compared both models and concluded that the Quantum Projection model achieves the same results as its classical counterpart, because the quantum interference effects play no role in the computation of the probabilities. Second, it intends to propose an alternative relativistic interpretation for rotation parameters that are involved in both classical and quantum models. In the end, instead of interpreting these parameters as a similarity measure between questions, we propose that they emerge due to the lack of knowledge concerned with a personal basis state and also due to uncertainties towards the state of world and towards the context of the questions.
Understanding quantum work in a quantum many-body system.
Wang, Qian; Quan, H T
2017-03-01
Based on previous studies in a single-particle system in both the integrable [Jarzynski, Quan, and Rahav, Phys. Rev. X 5, 031038 (2015)2160-330810.1103/PhysRevX.5.031038] and the chaotic systems [Zhu, Gong, Wu, and Quan, Phys. Rev. E 93, 062108 (2016)1539-375510.1103/PhysRevE.93.062108], we study the the correspondence principle between quantum and classical work distributions in a quantum many-body system. Even though the interaction and the indistinguishability of identical particles increase the complexity of the system, we find that for a quantum many-body system the quantum work distribution still converges to its classical counterpart in the semiclassical limit. Our results imply that there exists a correspondence principle between quantum and classical work distributions in an interacting quantum many-body system, especially in the large particle number limit, and further justify the definition of quantum work via two-point energy measurements in quantum many-body systems.
Spectroscopy characterization and quantum yield determination of quantum dots
NASA Astrophysics Data System (ADS)
Contreras Ortiz, S. N.; Mejía Ospino, E.; Cabanzo, R.
2016-02-01
In this paper we show the characterization of two kinds of quantum dots: hydrophilic and hydrophobic, with core and core/shell respectively, using spectroscopy techniques such as UV-Vis, fluorescence and Raman. We determined the quantum yield in the quantum dots using the quinine sulphate as standard. This salt is commonly used because of its quantum yield (56%) and stability. For the CdTe excitation, we used a wavelength of 549nm and for the CdSe/ZnS excitation a wavelength of 527nm. The results show that CdSe/ZnS (49%) has better fluorescence, better quantum dots, and confirm the fluorescence result. The quantum dots have shown a good fluorescence performance, so this property will be used to replace dyes, with the advantage that quantum dots are less toxic than some dyes like the rhodamine. In addition, in this work we show different techniques to find the quantum dots emission: fluorescence spectrum, synchronous spectrum and Raman spectrum.