WorldWideScience

Sample records for multivalued memory effects

  1. Multi-Valued Associative Memory Neural Network

    Institute of Scientific and Technical Information of China (English)

    修春波; 刘向东; 张宇河

    2003-01-01

    A novel learning method for multi-valued associative memory network is introduced, which is based on Hebb rule, but utilizes more information. According to the current probe vector, the connection weights matrix could be chosen dynamically. Double-valued and multi-valued associative memory are all realized in our simulation experiment. The experimental results show that the method could enhance the associative success rate.

  2. Multivalued associative memories based on recurrent networks.

    Science.gov (United States)

    Chiueh, T D; Tsai, H K

    1993-01-01

    A multivalued neural associative memory model based on a recurrent network structure is proposed. This model adopts the same principle proposed in the authors' previous work, the exponential correlation associative memories (ECAM). The model also has a very high storage capacity and strong error-correction capability. The major components of the new model include a weighted average process and some similarity-measure computation. As in ECAM, in order to enhance the differences among the weights and make the largest weights more overwhelming, the new model incorporates a nonlinear function in the calculation of weights. Several possible similarity measures suitable for this model are suggested. Simulation results of the performance of the new model with different measures show that, loaded with 500 64-component patterns, the model can sustain noise with power about one fifth to three fifths of the average signal power.

  3. Use of the asymmetric planar hall resistance of an Fe film for possible multi-value memory device applications.

    Science.gov (United States)

    Yoo, Taehee; Khym, S; Lee, Hakjoon; Lee, Sangyeop; Kim, Shinhee; Shin, Jinsik; Lee, Sanghoon; Liu, X; Furdyna, J K

    2011-07-01

    Systematic planar Hall measurements have been performed on a ferromagnetic Fe film grown on a standard (001) GaAs substrate at room temperature. The angular dependence of the planar Hall effect revealed the presence of both four-fold (cubic) and two-fold (uniaxial) anisotropies in the 7 nm thick Fe film. The dominance of the four-fold symmetric anisotropy, however, provided four magnetic easy axes near the (100) direction, which results in a two step switching phenomenon in the magnetization reversal process. An interesting asymmetric hysteresis loop was observed in the planar Hall resistance (PHR) when the turning point of the field scan is set at the value in the region of the second transition. The intermediate resistance states appearing in the asymmetric PHR loop were understood in terms of mutli-domain structures formed during the second switching of magnetization. Such multi-domain structure of the Fe film showing robust time stability provided additional Hall resistance states, which can be used for multi-valued memory device applications.

  4. Multivalued Exponential Multidirectional Associative Memory%多值指数式多向联想记忆模型

    Institute of Scientific and Technical Information of China (English)

    陈松灿; 高航

    1998-01-01

    多向联想记忆MDAM(multidirectional associative memory)模型是Kosko双向联想记忆模型BAM(bidirectional associative memory)的一个直接推广,它可应用于数据融合及维数分裂,使模型能处理大维数输入问题.目前所提出的若干种多向模型均局限于二值输入/输出模式对,但如在图象处理等的实际应用中,所处理的模式均是多值的.本文的目的就是提出一个多值指数式多向联想记忆模型MVeMDAM(multivalued exponential multidirectional associative memory),证明其在同步和异步更新方式下的稳定性,从而确保多值模式对成为MVeMDAM的稳定态.最后给出的计算机模拟证实了MVeMDAM的可行性.

  5. Comments on "Capacity Analysis of the Asymptotically Stable Multi-Valued Exponential Bidirectinal Associative Memory"

    Institute of Scientific and Technical Information of China (English)

    CHEN Lei; YANG Geng; XU Bi-huan

    2011-01-01

    Asymptotical stability is an important property of the associative memory neural networks. In this comment, we demonstrate that the asymptotical stability analyses of the MV-ECAM and MV-eBAM in the asynchronous update mode by Wang et al are not rigorous, and then we modify the errors and further prove that the two models are all asymptotically stable in both synchronous and asynchronous update modes.

  6. Generalized Wellposedness and Multivalued Contraction

    OpenAIRE

    PRABACKAR, Arockia; UTHAYAKUMAR, Ramasamy

    2014-01-01

    In this paper, we establish the fixed point theorem for multivalued contraction. Also we prove that the generalized well posedness of the fixed point problem and continuity of multivalued contraction. 

  7. A NOVEL MULTI-VALUED BAM MODEL WITH IMPROVED ERROR-CORRECTING CAPABILITY

    Institute of Scientific and Technical Information of China (English)

    Zhang Daoqiang; Chen Songcan

    2003-01-01

    A Hyperbolic Tangent multi-valued Bi-directional Associative Memory (HTBAM)model is proposed in this letter. Two general energy functions are defined to prove the stabilityof one class of multi-valued Bi-directional Associative Memorys(BAMs), with HTBAM being thespecial case. Simulation results show that HTBAM has a competitive storage capacity and muchmore error-correcting capability than other multi-valued BAMs.

  8. Multi-valued fields

    CERN Document Server

    Ershov, Yuri L

    2001-01-01

    For more than 30 years, the author has studied the model-theoretic aspects of the theory of valued fields and multi-valued fields. Many of the key results included in this book were obtained by the author whilst preparing the manuscript. Thus the unique overview of the theory, as developed in the book, has been previously unavailable. The book deals with the theory of valued fields and mutli-valued fields. The theory of Prüfer rings is discussed from the `geometric' point of view. The author shows that by introducing the Zariski topology on families of valuation rings, it is possible to distinguish two important subfamilies of Prüfer rings that correspond to Boolean and near Boolean families of valuation rings. Also, algebraic and model-theoretic properties of multi-valued fields with near Boolean families of valuation rings satisfying the local-global principle are studied. It is important that this principle is elementary, i.e., it can be expressed in the language of predicate calculus. The most important...

  9. Stability of discrete systems near a multivalued equilibrium

    Energy Technology Data Exchange (ETDEWEB)

    Kuntsevich, V.M.; Pokotilo, V.G.

    1995-01-01

    The main objective of this article is to derive sufficient conditions of stability in the small for ensembles of trajectories of nonlinar discrete systems near multivalued equilibria. The stability conditions are expressed in terms of a linearized system, and we examine the effect of the structure of invariant sets near which the behavior of the system is investigated. On the one hand, this approach provides a clearer picture of the specific features of multivalued systems and, on the other hand, it produces results that characterize stability of analogs of periodic motion.

  10. 多重加权多值指数双向联想记忆网络及其表决性能%Multiple Weighted Multivalued Exponential Bidirectional Associative Memory Network and Its Voting Performance

    Institute of Scientific and Technical Information of China (English)

    陈松灿; 蔡骏

    2001-01-01

    Wang和陈等利用各自提出的二值指数双向联想记忆模型(eBAM)及其改进型eBAM(IeBAM),分别构造了由多个eBAM和IeBAM组成的多重eBAM(Multi-eBAM)和多重IeBAM(Multi-IeBAM)的信念组合模型,使之可模拟多个专家的表决.该文在此基础上,借助陈提出的多值eBAM(MVeBAM),提出了多重多值eBAM(Multi-MVeBAM),对Multi-eBAM和Multi-IeBAM进行了两方面的推广:一是将二值表示推广到多值表示,以此可以处理现实中的多值数据;二是将原有模型中具有同等权威度的各专家推广到各具不同的权威度的专家,以此模拟更实际的表决情形.文中借助能量函数证明了所提模型的渐近稳定性,以保证其实际可用.计算机模拟证实了模型的可行性.%Wang and Chen, together with their coworkers, adopted their binary exponential bidirectional associative memory(eBAM) and improved eBAM(IeBAM) to build their multiple eBAM(Multi-eBAM) and multiple IeBAM(Multi-IeBAM) belief combination models respectively composed of eBAM and IeBAM to mimic the voting of many experts. In this paper, on the basis of their models and with the use of Chen multivalued eBAM(MVeBAM), a new multiple weighted MVeBAM(Multi-WMVeBAM) model is presented which extends both Multi-eBAM and Multi-IeBAM in two aspects: one is the extension from binary to multivalued data format , the other is to apply different weights to all experts so that the proposed model can mimic a voting process in practice. By defining an energy function, the stability of the Multi-WMVeBAM in synchronous and asynchronous updating modes is proven which ensures its applicability in the real world. Finally computer simulations confirm its feasiblity.

  11. Memory effects in turbulence

    Science.gov (United States)

    Hinze, J. O.

    1979-01-01

    Experimental investigations of the wake flow of a hemisphere and cylinder show that such memory effects can be substantial and have a significant influence on momentum transport. Memory effects are described in terms of suitable memory functions.

  12. Dynamics of multivalued linear operators

    Directory of Open Access Journals (Sweden)

    Chen Chung-Chuan

    2017-07-01

    Full Text Available We introduce several notions of linear dynamics for multivalued linear operators (MLO’s between separable Fréchet spaces, such as hypercyclicity, topological transitivity, topologically mixing property, and Devaney chaos. We also consider the case of disjointness, in which any of these properties are simultaneously satisfied by several operators. We revisit some sufficient well-known computable criteria for determining those properties. The analysis of the dynamics of extensions of linear operators to MLO’s is also considered.

  13. Design of Multivalued Circuits Based on an Algebra for Current—Mode CMOS Multivalued Circuits

    Institute of Scientific and Technical Information of China (English)

    陈偕雄; ClaudioMoraga

    1995-01-01

    An algebra proposed for current-mode CMOS multivalued circuits is briefly reviewed.this paper discusses its application in the design of multivalued circuits.Several current-mode CMOS quaternary and quinary circuits are designed by algebraic means.The design method based on this algebra may offer a design simpler than the previously known ones.

  14. FPGA-oriented synthesis of multivalued logical networks

    Science.gov (United States)

    Deniziak, S.; Wiśniewski, M.; Kurczyna, K.

    2016-12-01

    Multivalued logical network consists of modules connected by multivalued signals. During synthesis each module is decomposed into smaller ones using the symbolic decomposition. Since the efficiency of the decomposition strongly depends on encoding of multivalued signals, the result of synthesis depends on the order, in which the consecutive modules are implemented. This paper presents the method of FPGA-oriented synthesis of multivalued logical networks. Experimental results showed that our approach significantly reduces the cost of implementation.

  15. Trinary flip-flops using Savart plate and spatial light modu-lator for optical computation in multivalued logic

    Institute of Scientific and Technical Information of China (English)

    Areal K Ghosh; Amitabha Basuray

    2008-01-01

    The memory devices in multi-valued logic are of most significance in modern research. This paper deals with the imple-mentation of basic memory devices in multi-valued logic using Savart plate and spatial light modulator (SLM) basedoptoelectronic circuits. Photons are used here as the carrier to speed up the operations. Optical tree architecture (OTA) hasbeen also utilized in the optical interconnection network. We have exploited the advantages of Savart plates, SLMs andOTA and proposed the SLM based high speed JK, D-type and T-type flip-flops in a trinary system.

  16. The Cosmological Memory Effect

    OpenAIRE

    Tolish, Alexander; Wald, Robert M.

    2016-01-01

    The "memory effect" is the permanent change in the relative separation of test particles resulting from the passage of gravitational radiation. We investigate the memory effect for a general, spatially flat FLRW cosmology by considering the radiation associated with emission events involving particle-like sources. We find that if the resulting perturbation is decomposed into scalar, vector, and tensor parts, only the tensor part contributes to memory. Furthermore, the tensor contribution to m...

  17. Theory of Selection Operators on Hyperspaces and Multivalued Stochastic Processes

    Institute of Scientific and Technical Information of China (English)

    高勇; 张文修

    1994-01-01

    In this paper, a new concept of selection operators on hyperspaces (subsets spaces) is introduced, and the existence theorems for several kinds of selection operators are proved. Using the methods of selection operators, we give a selection characterization of identically distributed multivalued random variables and completely solve the vector-valued selection problem for sequences of multivalued random variables converging in distribution. The regular selections and Markov selections for multivalued stochastic processes are studied, and a discretization theorem for multivalued Markov processes is established. A theorem on the asymptotic martingale selections for compact and convex multivalued asymptotic martingale is proved.

  18. Dialectical Multivalued Logic and Probabilistic Theory

    Directory of Open Access Journals (Sweden)

    José Luis Usó Doménech

    2017-02-01

    Full Text Available There are two probabilistic algebras: one for classical probability and the other for quantum mechanics. Naturally, it is the relation to the object that decides, as in the case of logic, which algebra is to be used. From a paraconsistent multivalued logic therefore, one can derive a probability theory, adding the correspondence between truth value and fortuity.

  19. Cosmological memory effect

    Science.gov (United States)

    Tolish, Alexander; Wald, Robert M.

    2016-08-01

    The "memory effect" is the permanent change in the relative separation of test particles resulting from the passage of gravitational radiation. We investigate the memory effect for a general, spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) cosmology by considering the radiation associated with emission events involving particle-like sources. We find that if the resulting perturbation is decomposed into scalar, vector, and tensor parts, only the tensor part contributes to memory. Furthermore, the tensor contribution to memory depends only on the cosmological scale factor at the source and observation events, not on the detailed expansion history of the universe. In particular, for sources at the same luminosity distance, the memory effect in a spatially flat FLRW spacetime is enhanced over the Minkowski case by a factor of (1 +z ).

  20. The Cosmological Memory Effect

    CERN Document Server

    Tolish, Alexander

    2016-01-01

    The "memory effect" is the permanent change in the relative separation of test particles resulting from the passage of gravitational radiation. We investigate the memory effect for a general, spatially flat FLRW cosmology by considering the radiation associated with emission events involving particle-like sources. We find that if the resulting perturbation is decomposed into scalar, vector, and tensor parts, only the tensor part contributes to memory. Furthermore, the tensor contribution to memory depends only on the cosmological scale factor at the source and observation events, not on the detailed expansion history of the universe. In particular, for sources at the same luminosity distance, the memory effect in a spatially flat FLRW spacetime is enhanced over the Minkowski case by a factor of $(1 + z)$.

  1. Nonlinear Elliptic Differential Equations with Multivalued Nonlinearities

    Indian Academy of Sciences (India)

    Antonella Fiacca; Nikolaos Matzakos; Nikolaos S Papageorgiou; Raffaella Servadei

    2001-11-01

    In this paper we study nonlinear elliptic boundary value problems with monotone and nonmonotone multivalued nonlinearities. First we consider the case of monotone nonlinearities. In the first result we assume that the multivalued nonlinearity is defined on all $\\mathbb{R}$. Assuming the existence of an upper and of a lower solution, we prove the existence of a solution between them. Also for a special version of the problem, we prove the existence of extremal solutions in the order interval formed by the upper and lower solutions. Then we drop the requirement that the monotone nonlinearity is defined on all of $\\mathbb{R}$. This case is important because it covers variational inequalities. Using the theory of operators of monotone type we show that the problem has a solution. Finally in the last part we consider an eigenvalue problem with a nonmonotone multivalued nonlinearity. Using the critical point theory for nonsmooth locally Lipschitz functionals we prove the existence of at least two nontrivial solutions (multiplicity theorem).

  2. MULTI-VALUED QUASI VARLATIONAL INCLUSIONS IN BANACH SPACES

    Institute of Scientific and Technical Information of China (English)

    张石生

    2004-01-01

    The purpose is to introduce and study a class of more general multivalued quasi variational inclusions in Banach spaces.By using the resolvent operator technique some existence theorem of solutions and iterative approximation for solving this kind of multivalued quasi variational inclusions are established.The results generalize,improve and unify a number of Noor's and others' recent results.

  3. A multivalued knowledge-base model

    CERN Document Server

    Achs, Agnes

    2010-01-01

    The basic aim of our study is to give a possible model for handling uncertain information. This model is worked out in the framework of DATALOG. At first the concept of fuzzy Datalog will be summarized, then its extensions for intuitionistic- and interval-valued fuzzy logic is given and the concept of bipolar fuzzy Datalog is introduced. Based on these ideas the concept of multivalued knowledge-base will be defined as a quadruple of any background knowledge; a deduction mechanism; a connecting algorithm, and a function set of the program, which help us to determine the uncertainty levels of the results. At last a possible evaluation strategy is given.

  4. Nonlinear Second-Order Multivalued Boundary Value Problems

    Indian Academy of Sciences (India)

    Leszek Gasiński; Nikolaos S Papageorgiou

    2003-08-01

    In this paper we study nonlinear second-order differential inclusions involving the ordinary vector -Laplacian, a multivalued maximal monotone operator and nonlinear multivalued boundary conditions. Our framework is general and unifying and incorporates gradient systems, evolutionary variational inequalities and the classical boundary value problems, namely the Dirichlet, the Neumann and the periodic problems. Using notions and techniques from the nonlinear operatory theory and from multivalued analysis, we obtain solutions for both the `convex' and `nonconvex' problems. Finally, we present the cases of special interest, which fit into our framework, illustrating the generality of our results.

  5. Topological fixed point theory of multivalued mappings

    CERN Document Server

    Górniewicz, Lech

    1999-01-01

    This volume presents a broad introduction to the topological fixed point theory of multivalued (set-valued) mappings, treating both classical concepts as well as modern techniques. A variety of up-to-date results is described within a unified framework. Topics covered include the basic theory of set-valued mappings with both convex and nonconvex values, approximation and homological methods in the fixed point theory together with a thorough discussion of various index theories for mappings with a topologically complex structure of values, applications to many fields of mathematics, mathematical economics and related subjects, and the fixed point approach to the theory of ordinary differential inclusions. The work emphasises the topological aspect of the theory, and gives special attention to the Lefschetz and Nielsen fixed point theory for acyclic valued mappings with diverse compactness assumptions via graph approximation and the homological approach. Audience: This work will be of interest to researchers an...

  6. Large Deviations for Multi-valued Stochastic Differential Equations

    CERN Document Server

    Ren, Jiagang; Zhang, Xicheng

    2009-01-01

    We prove a large deviation principle of Freidlin-Wentzell's type for the multivalued stochastic differential equations with monotone drifts, which in particular contains a class of SDEs with reflection in a convex domain.

  7. Multivalued Stochastic Differential Equations with Non-Lipschitz Coefficients

    Institute of Scientific and Technical Information of China (English)

    Siyan XU

    2009-01-01

    The existence and uniqueness of solutions to the multivalued stochastic differ-ential equations with non-Lipschitz coefficients are proved, and bicontinuons modifications of the solutions are obtained.

  8. Generalized $ f $-nonexpansive R-subweakly commuting multivalued maps

    Directory of Open Access Journals (Sweden)

    P. Vijayaraju

    2007-12-01

    Full Text Available WWe prove coincidence point theorems for the generalized $ f $-nonexpansive R-subweakly commuting multivalued maps. Our results generalize and extend well known results for noncommuting maps.

  9. Consistent Algorithm for Multi-value Constraint with Continuous Variables

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    Mature algorithms for the Constraint Satisfaction Problem (CSP) of binary constraint with discrete variables have already been obtained for the application. For the instance of multi-value constraint with continuous variables, the approach will be quite different and the difficulty of settling will aggrandize a lot. This paper presents the algorithm for realizing global consistency of continuous variable. And this algorithm can be applied to multi-value constraint.

  10. Random attractors for asymptotically upper semicompact multivalue random semiflows

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The present paper studied the dynamics of some multivalued random semiflow. The corresponding concept of random attractor for this case was introduced to study asymptotic behavior. The existence of random attractor of multivalued random semiflow was proved under the assumption of pullback asymptotically upper semicompact, and this random attractor is random compact and invariant. Furthermore, if the system has ergodicity, then this random attractor is the limit set of a deterministic bounded set.

  11. 基于多值中智集的TODIM方法%TODIM method with multi-valued neutrosophic sets

    Institute of Scientific and Technical Information of China (English)

    王坚强; 李新娥

    2015-01-01

    The multi-valued neutrosophic set, the multi-valued neutrosophic number and its expected value as well as the Hamming distance between two multi-valued neutrosophic numbers are defined. Besides, the comparison rules between two multi-valued neutrosophic numbers are also given. For the multi-criteria decision making with multi-valued neutrosophic sets, the traditional TODIM method is extended, and an approach is given. In this method, a reference criterion is selected and then a value function is built based on the Hamming distance between multi-valued neutrosophic numbers. This value function is used to get the ranking order of all alternatives. Finally, a numerical example is given to show the effectiveness and feasibility of the proposed method.%定义了多值中智集、多值中智数及其期望值以及多值中智数的Hamming距离,并给出了其比较方法。针对准则值为多值中智数的多准则决策问题,将传统的交互式多准则决策(TODIM)方法扩展到多值中智环境中,提出一种基于多值中智集的多准则决策方法。该方法首先选定参考准则;然后以多值中智集的距离为基础构建方案间的价值函数,以得到方案间的优势矩阵,进而计算得到方案的综合排序值;最后通过实例分析表明了该方法的有效性和可行性。

  12. General Large Deviations and Functional Iterated Logarithm Law for Multivalued Stochastic Differential Equations

    OpenAIRE

    Ren, Jiagang; Wu, Jing; Zhang, Hua

    2015-01-01

    In this paper, we prove a large deviation principle of Freidlin-Wentzell's type for the multivalued stochastic differential equations. As an application, we derive a functional iterated logarithm law for the solutions of multivalued stochastic differential equations.

  13. Abstracting Asynchronous Multi-Valued Networks: An Initial Investigation

    CERN Document Server

    Steggles, L Jason

    2011-01-01

    Multi-valued networks provide a simple yet expressive qualitative state based modelling approach for biological systems. In this paper we develop an abstraction theory for asynchronous multi-valued network models that allows the state space of a model to be reduced while preserving key properties of the model. The abstraction theory therefore provides a mechanism for coping with the state space explosion problem and supports the analysis and comparison of multi-valued networks. We take as our starting point the abstraction theory for synchronous multi-valued networks which is based on the finite set of traces that represent the behaviour of such a model. The problem with extending this approach to the asynchronous case is that we can now have an infinite set of traces associated with a model making a simple trace inclusion test infeasible. To address this we develop a decision procedure for checking asynchronous abstractions based on using the finite state graph of an asynchronous multi-valued network to reas...

  14. Existence and Stability of Solutions for Implicit Multivalued Vector Equilibrium Problems

    Directory of Open Access Journals (Sweden)

    Li Qiuying

    2011-01-01

    Full Text Available A class of implicit multivalued vector equilibrium problems is studied. By using the generalized Fan-Browder fixed point theorem, some existence results of solutions for the implicit multivalued vector equilibrium problems are obtained under some suitable assumptions. Moreover, a stability result of solutions for the implicit multivalued vector equilibrium problems is derived. These results extend and unify some recent results for implicit vector equilibrium problems, multivalued vector variational inequality problems, and vector variational inequality problems.

  15. Completely generalized multivalued nonlinear quasi-variational inclusions

    Directory of Open Access Journals (Sweden)

    Zeqing Liu

    2002-01-01

    Full Text Available We introduce and study a new class of completely generalized multivalued nonlinear quasi-variational inclusions. Using the resolvent operator technique for maximal monotone mappings, we suggest two kinds of iterative algorithms for solving the completely generalized multivalued nonlinear quasi-variational inclusions. We establish both four existence theorems of solutions for the class of completely generalized multivalued nonlinear quasi-variational inclusions involving strongly monotone, relaxed Lipschitz, and generalized pseudocontractive mappings, and obtain a few convergence results of iterative sequences generated by the algorithms. The results presented in this paper extend, improve, and unify a lot of results due to Adly, Huang, Jou-Yao, Kazmi, Noor, Noor-Al-Said, Noor-Noor, Noor-Noor-Rassias, Shim-Kang-Huang-Cho, Siddiqi-Ansari, Verma, Yao, and Zhang.

  16. Variational multi-valued velocity field estimation for transparent sequences

    DEFF Research Database (Denmark)

    Ramirez-Manzanares, Alonso; Rivera, Mariano; Kornprobst, Pierre;

    2011-01-01

    Motion estimation in sequences with transparencies is an important problem in robotics and medical imaging applications. In this work we propose a variational approach for estimating multi-valued velocity fields in transparent sequences. Starting from existing local motion estimators, we derive a...

  17. Common fixed points of single-valued and multivalued maps

    Directory of Open Access Journals (Sweden)

    Yicheng Liu

    2005-01-01

    Full Text Available We define a new property which contains the property (EA for a hybrid pair of single- and multivalued maps and give some new common fixed point theorems under hybrid contractive conditions. Our results extend previous ones. As an application, we give a partial answer to the problem raised by Singh and Mishra.

  18. Solvent-driven temperature memory and multiple shape memory effects.

    Science.gov (United States)

    Xiao, Rui; Guo, Jingkai; Safranski, David L; Nguyen, Thao D

    2015-05-28

    Thermally-activated temperature memory and multiple shape memory effects have been observed in amorphous polymers with a broad glass transition. In this work, we demonstrate that the same shape recovery behaviors can also be achieved through solvent absorption. We investigate the recovery behaviors of programmed Nafion membranes in various solvents and compare the solvent-driven and temperature-driven shape recovery response. The results show that the programming temperature and solvent type have a corresponding strong influence on the shape recovery behavior. Specifically, lower programming temperatures induce faster initial recovery rates and larger recovery, which is known as the temperature memory effect. The temperature memory effect can be used to achieve multi-staged and multiple shape recovery of specimens programmed at different temperatures. Different solvents can also induce different shape recovery, analogous to the temperature memory effect, and can also provide a mechanism for multi-staged and multiple shape memory recovery.

  19. Effect sizes in memory research.

    Science.gov (United States)

    Morris, Peter E; Fritz, Catherine O

    2013-01-01

    Effect sizes are omitted from many research articles and are rarely discussed. To help researchers evaluate effect sizes we collected values for the more commonly reported effect size measures (partial eta squared and d) from papers reporting memory research published in 2010. Cohen's small, medium, and large generic guideline values for d mapped neatly onto the observed distributions, but his values for partial eta squared were considerably lower than those observed in current memory research. We recommend interpreting effect sizes in the context of either domain-specific guideline values agreed for an area of research or the distribution of effect size estimates from published research in the domain. We provide cumulative frequency tables for both partial eta squared and d enabling authors to report and consider not only the absolute size of observed effects but also the percentage of reported effects that are larger or smaller than those observed.

  20. Memory effect in growing trees

    OpenAIRE

    Malarz, K.; Kulakowski, K.

    2003-01-01

    We show that the structure of a growing tree preserves an information on the shape of an initial graph. For the exponential trees, evidence of this kind of memory is provided by means of the iterative equations, derived for the moments of the node-node distance distribution. Numerical calculations confirm the result and allow to extend the conclusion to the Barabasi--Albert scale-free trees. The memory effect almost disappears, if subsequent nodes are connected to the network with more than o...

  1. Fixed Points of Multivalued Contractive Mappings in Partial Metric Spaces

    Directory of Open Access Journals (Sweden)

    Abdul Rahim Khan

    2014-01-01

    Full Text Available The aim of this paper is to present fixed point results of multivalued mappings in the framework of partial metric spaces. Some examples are presented to support the results proved herein. Our results generalize and extend various results in the existing literature. As an application of our main result, the existence and uniqueness of bounded solution of functional equations arising in dynamic programming are established.

  2. Approximate Compilation of Constraints into Multivalued Decision Diagrams

    DEFF Research Database (Denmark)

    Hadzic, Tarik; Hooker, John N.; O’Sullivan, Barry;

    2008-01-01

    We present an incremental refinement algorithm for approximate compilation of constraint satisfaction models into multivalued decision diagrams (MDDs). The algorithm uses a vertex splitting operation that relies on the detection of equivalent paths in the MDD. Although the algorithm is quite...... by replacing the equivalence test with a constraint-specific measure of distance. We demonstrate the value of the approach for approximate and exact MDD compilation and evaluate its benefits in one of the main MDD application domains, interactive configuration....

  3. Fixed Points of Multivalued Maps in Modular Function Spaces

    Directory of Open Access Journals (Sweden)

    Kutbi MarwanA

    2009-01-01

    Full Text Available The purpose of this paper is to study the existence of fixed points for contractive-type and nonexpansive-type multivalued maps in the setting of modular function spaces. We also discuss the concept of -modular function and prove fixed point results for weakly-modular contractive maps in modular function spaces. These results extend several similar results proved in metric and Banach spaces settings.

  4. Using Multivalued Logic in Relational Database Containing Null Value

    Institute of Scientific and Technical Information of China (English)

    马宗民; YanLi

    1996-01-01

    In this paper,several kinds of multivalued logic for relational database and their developing process are presented on the basis of null value's semantics.A new 5 valued logic is led into relational database containing null value.The feasibility and necessity of using 5 valued logic are expounded.Comparative calculation and logical calculation under 5 valued logic are defined at the end of the paper.

  5. Shape Memory Effect and Properties Memory Effect of Polyurethane

    OpenAIRE

    FARZANEH, Sedigeh; Fitoussi, Joseph; LUCAS, Albert; Bocquet, Michel; Tcharkhtchi, Abbas

    2013-01-01

    International audience; The relationship between shape and properties memory effect, especially viscoelastic properties of polyurethane under study is the main aim of this research work. Tensile tests have been performed in order to introduce 100% of deformation in the polyurethane samples. Under this deformation, stress-relaxation experiments have been performed in order to eliminate the residual stresses. This deformation of the samples has been fixed by cooling. Recovery tests, then, were ...

  6. Online learning of single- and multivalued functions with an infinite mixture of linear experts.

    Science.gov (United States)

    Damas, Bruno; Santos-Victor, José

    2013-11-01

    We present a supervised learning algorithm for estimation of generic input-output relations in a real-time, online fashion. The proposed method is based on a generalized expectation-maximization approach to fit an infinite mixture of linear experts (IMLE) to an online stream of data samples. This probabilistic model, while not fully Bayesian, can efficiently choose the number of experts that are allocated to the mixture, this way effectively controlling the complexity of the resulting model. The result is an incremental, online, and localized learning algorithm that performs nonlinear, multivariate regression on multivariate outputs by approximating the target function by a linear relation within each expert input domain and that can allocate new experts as needed. A distinctive feature of the proposed method is the ability to learn multivalued functions: one-to-many mappings that naturally arise in some robotic and computer vision learning domains, using an approach based on a Bayesian generative model for the predictions provided by each of the mixture experts. As a consequence, it is able to directly provide forward and inverse relations from the same learned mixture model. We conduct an extensive set of experiments to evaluate the proposed algorithm performance, and the results show that it can outperform state-of-the-art online function approximation algorithms in single-valued regression, while demonstrating good estimation capabilities in a multivalued function approximation context.

  7. An improved multi-value cellular automata model for heterogeneous bicycle traffic flow

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Sheng [College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, 310058 China (China); Qu, Xiaobo [Griffith School of Engineering, Griffith University, Gold Coast, 4222 Australia (Australia); Xu, Cheng [Department of Transportation Management Engineering, Zhejiang Police College, Hangzhou, 310053 China (China); College of Transportation, Jilin University, Changchun, 130022 China (China); Ma, Dongfang, E-mail: mdf2004@zju.edu.cn [Ocean College, Zhejiang University, Hangzhou, 310058 China (China); Wang, Dianhai [College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, 310058 China (China)

    2015-10-16

    This letter develops an improved multi-value cellular automata model for heterogeneous bicycle traffic flow taking the higher maximum speed of electric bicycles into consideration. The update rules of both regular and electric bicycles are improved, with maximum speeds of two and three cells per second respectively. Numerical simulation results for deterministic and stochastic cases are obtained. The fundamental diagrams and multiple states effects under different model parameters are analyzed and discussed. Field observations were made to calibrate the slowdown probabilities. The results imply that the improved extended Burgers cellular automata (IEBCA) model is more consistent with the field observations than previous models and greatly enhances the realism of the bicycle traffic model. - Highlights: • We proposed an improved multi-value CA model with higher maximum speed. • Update rules are introduced for heterogeneous bicycle traffic with maximum speed 2 and 3 cells/s. • Simulation results of the proposed model are consistent with field bicycle data. • Slowdown probabilities of both regular and electric bicycles are calibrated.

  8. Memory effects in nanoparticle dynamics and transport

    Science.gov (United States)

    Sanghi, Tarun; Bhadauria, Ravi; Aluru, N. R.

    2016-10-01

    In this work, we use the generalized Langevin equation (GLE) to characterize and understand memory effects in nanoparticle dynamics and transport. Using the GLE formulation, we compute the memory function and investigate its scaling with the mass, shape, and size of the nanoparticle. It is observed that changing the mass of the nanoparticle leads to a rescaling of the memory function with the reduced mass of the system. Further, we show that for different mass nanoparticles it is the initial value of the memory function and not its relaxation time that determines the "memory" or "memoryless" dynamics. The size and the shape of the nanoparticle are found to influence both the functional-form and the initial value of the memory function. For a fixed mass nanoparticle, increasing its size enhances the memory effects. Using GLE simulations we also investigate and highlight the role of memory in nanoparticle dynamics and transport.

  9. Novelty's effect on memory encoding.

    Science.gov (United States)

    Rangel-Gomez, Mauricio; Janenaite, Sigita; Meeter, Martijn

    2015-07-01

    It is often thought that novelty benefits memory formation. However, support for this idea mostly comes from paradigms that are open to alternative explanations. In the present study we manipulated novelty in a word-learning task through task-irrelevant background images. These background images were either standard (presented repeatedly), or novel (presented only once). Two types of background images were used: Landscape pictures and fractals. EEG was also recorded during encoding. Contrary to the idea that novelty aids memory formation, memory performance was not affected by the novelty of the background. In the evoked response potentials, we found evidence of distracting effects of novelty: both the N1 and P3b components were smaller to words studied with novel backgrounds, and the amplitude of the N2b component correlated negatively with subsequent retrieval. We conclude that although evidence from other studies does suggest benefits on a longer time scale, novelty has no instantaneous benefits for learning. Copyright © 2015 Elsevier B.V. All rights reserved.

  10. Stress effects on working memory, explicit memory, and implicit memory for neutral and emotional stimuli in healthy men

    OpenAIRE

    Mathias Luethi; Beat Meier; Carmen Sandi

    2009-01-01

    Stress is a strong modulator of memory function. However, memory is not a unitary process and stress seems to exert different effects depending on the memory type under study. Here, we explored the impact of social stress on different aspects of human memory, including tests for explicit memory and working memory (for neutral materials), as well as implicit memory (perceptual priming, contextual priming and classical conditioning for emotional stimuli). A total of 35 young adult...

  11. Stress Effects on Multiple Memory System Interactions.

    Science.gov (United States)

    Ness, Deborah; Calabrese, Pasquale

    2016-01-01

    Extensive behavioural, pharmacological, and neurological research reports stress effects on mammalian memory processes. While stress effects on memory quantity have been known for decades, the influence of stress on multiple memory systems and their distinct contributions to the learning process have only recently been described. In this paper, after summarizing the fundamental biological aspects of stress/emotional arousal and recapitulating functionally and anatomically distinct memory systems, we review recent animal and human studies exploring the effects of stress on multiple memory systems. Apart from discussing the interaction between distinct memory systems in stressful situations, we will also outline the fundamental role of the amygdala in mediating such stress effects. Additionally, based on the methods applied in the herein discussed studies, we will discuss how memory translates into behaviour.

  12. Stress Effects on Multiple Memory System Interactions

    Directory of Open Access Journals (Sweden)

    Deborah Ness

    2016-01-01

    Full Text Available Extensive behavioural, pharmacological, and neurological research reports stress effects on mammalian memory processes. While stress effects on memory quantity have been known for decades, the influence of stress on multiple memory systems and their distinct contributions to the learning process have only recently been described. In this paper, after summarizing the fundamental biological aspects of stress/emotional arousal and recapitulating functionally and anatomically distinct memory systems, we review recent animal and human studies exploring the effects of stress on multiple memory systems. Apart from discussing the interaction between distinct memory systems in stressful situations, we will also outline the fundamental role of the amygdala in mediating such stress effects. Additionally, based on the methods applied in the herein discussed studies, we will discuss how memory translates into behaviour.

  13. ASP-based method for the enumeration of attractors in non-deterministic synchronous and asynchronous multi-valued networks.

    Science.gov (United States)

    Ben Abdallah, Emna; Folschette, Maxime; Roux, Olivier; Magnin, Morgan

    2017-01-01

    This paper addresses the problem of finding attractors in biological regulatory networks. We focus here on non-deterministic synchronous and asynchronous multi-valued networks, modeled using automata networks (AN). AN is a general and well-suited formalism to study complex interactions between different components (genes, proteins,...). An attractor is a minimal trap domain, that is, a part of the state-transition graph that cannot be escaped. Such structures are terminal components of the dynamics and take the form of steady states (singleton) or complex compositions of cycles (non-singleton). Studying the effect of a disease or a mutation on an organism requires finding the attractors in the model to understand the long-term behaviors. We present a computational logical method based on answer set programming (ASP) to identify all attractors. Performed without any network reduction, the method can be applied on any dynamical semantics. In this paper, we present the two most widespread non-deterministic semantics: the asynchronous and the synchronous updating modes. The logical approach goes through a complete enumeration of the states of the network in order to find the attractors without the necessity to construct the whole state-transition graph. We realize extensive computational experiments which show good performance and fit the expected theoretical results in the literature. The originality of our approach lies on the exhaustive enumeration of all possible (sets of) states verifying the properties of an attractor thanks to the use of ASP. Our method is applied to non-deterministic semantics in two different schemes (asynchronous and synchronous). The merits of our methods are illustrated by applying them to biological examples of various sizes and comparing the results with some existing approaches. It turns out that our approach succeeds to exhaustively enumerate on a desktop computer, in a large model (100 components), all existing attractors up to a given

  14. The gravitational-wave memory effect

    CERN Document Server

    Favata, Marc

    2010-01-01

    The nonlinear memory effect is a slowly-growing, non-oscillatory contribution to the gravitational-wave amplitude. It originates from gravitational waves that are sourced by the previously emitted waves. In an ideal gravitational-wave interferometer a gravitational-wave with memory causes a permanent displacement of the test masses that persists after the wave has passed. Surprisingly, the nonlinear memory affects the signal amplitude starting at leading (Newtonian-quadrupole) order. Despite this fact, the nonlinear memory is not easily extracted from current numerical relativity simulations. After reviewing the linear and nonlinear memory I summarize some recent work, including: (1) computations of the memory contribution to the inspiral waveform amplitude (thus completing the waveform to third post-Newtonian order); (2) the first calculations of the nonlinear memory that include all phases of binary black hole coalescence (inspiral, merger, ringdown); and (3) realistic estimates of the detectability of the ...

  15. Memory Effect and Fast Spinodal Decomposition

    OpenAIRE

    Koide, T.; Krein, Gastão Inácio [UNESP; Ramos, Rudnei O.

    2007-01-01

    We consider the modification of the Cahn-Hilliard equation when a time delay process through a memory function is taken into account. We then study the process of spinodal decomposition in fast phase transitions associated with a conserved order parameter. The introduced memory effect plays an important role to obtain a finite group velocity. Then, we discuss the constraint for the parameters to satisfy causality. The memory effect is seen to affect the dynamics of phase transition at short t...

  16. The Attentional Boost Effect and Context Memory

    Science.gov (United States)

    Mulligan, Neil W.; Smith, S. Adam; Spataro, Pietro

    2016-01-01

    Stimuli co-occurring with targets in a detection task are better remembered than stimuli co-occurring with distractors--the attentional boost effect (ABE). The ABE is of interest because it is an exception to the usual finding that divided attention during encoding impairs memory. The effect has been demonstrated in tests of item memory but it is…

  17. The gravitational-wave memory effect

    OpenAIRE

    Favata, Marc

    2010-01-01

    The nonlinear memory effect is a slowly-growing, non-oscillatory contribution to the gravitational-wave amplitude. It originates from gravitational waves that are sourced by the previously emitted waves. In an ideal gravitational-wave interferometer a gravitational-wave with memory causes a permanent displacement of the test masses that persists after the wave has passed. Surprisingly, the nonlinear memory affects the signal amplitude starting at leading (Newtonian-quadrupole) order. Despite ...

  18. Memory effects in turbulent transport

    CERN Document Server

    Hubbard, Alexander

    2008-01-01

    In mean-field theory of magnetic fields or passive scalars, for example, turbulent transport is usually assumed to be proportional to the corresponding mean fields and their spatial derivatives. However, this is an approximation that is valid only if the mean fields vary slowly in time. Examples are presented where turbulent transport possesses memory, i.e. it depends crucially on the past history of the mean fields at earlier times. Such effects are captured by replacing turbulent transport coefficients with time integral kernels, resulting in transport coefficients that depend effectively on the frequency or the growth rate of the mean fields themselves. In this paper we perform numerical experiments to find the characteristic timescale of this effect as well as simple analytical models of the integral kernels in the case of passive scalar concentrations and kinetic dynamos. The integral kernels can then be used to find self-consistent growth or decay rates of the mean fields. In mean-field dynamos the grow...

  19. Generating Probability Distributions using Multivalued Stochastic Relay Circuits

    CERN Document Server

    Lee, David

    2011-01-01

    The problem of random number generation dates back to von Neumann's work in 1951. Since then, many algorithms have been developed for generating unbiased bits from complex correlated sources as well as for generating arbitrary distributions from unbiased bits. An equally interesting, but less studied aspect is the structural component of random number generation as opposed to the algorithmic aspect. That is, given a network structure imposed by nature or physical devices, how can we build networks that generate arbitrary probability distributions in an optimal way? In this paper, we study the generation of arbitrary probability distributions in multivalued relay circuits, a generalization in which relays can take on any of N states and the logical 'and' and 'or' are replaced with 'min' and 'max' respectively. Previous work was done on two-state relays. We generalize these results, describing a duality property and networks that generate arbitrary rational probability distributions. We prove that these network...

  20. Dynamically Multivalued Self-Organisation and Probabilistic Structure Formation Processes

    CERN Document Server

    Kirilyuk, A P

    2004-01-01

    The unreduced, universally nonperturbative analysis of arbitrary many-body interaction process reveals the irreducible, purely dynamic source of randomness. It leads to the universal definition of real system complexity (physics/9806002), where the internally chaotic self-organisation emerges as a limiting case of complex interaction dynamics (physics/0211071). It extends also the concept of "self-organised criticality" and corresponds to formation of distinct enough (but always internally chaotic) structures occurring if the system is far from characteristic frequency resonances. Transition to the opposite limiting regime of multivalued interaction dynamics, that of uniform (global) chaos, takes place around the main frequency resonance(s), which provides the absolutely universal criterion of global chaos onset, applicable to any kind of system, as well as the new, extended interpretation of the phenomenon of resonance itself. As a result, one obtains the causally complete description of world structure emer...

  1. Two Step Modified Ishikawa Iteration Scheme for Multi-Valued Mappings in CAT(0 Space

    Directory of Open Access Journals (Sweden)

    Pankaj Kumar Jhade

    2013-11-01

    Full Text Available The aim of this paper is to prove some strong convergence theorems for the modified Ishikawa iteration scheme involving quasi-nonexpansive multi-valued mappings in the framework of CAT(0 spaces.

  2. Dynamical memory effects in correlated quantum channels

    Science.gov (United States)

    Addis, Carole; Karpat, Göktuǧ; Macchiavello, Chiara; Maniscalco, Sabrina

    2016-09-01

    Memory effects play a fundamental role in the study of the dynamics of open quantum systems. There exist two conceptually distinct notions of memory discussed for quantum channels in the literature. In quantum information theory quantum channels with memory are characterized by the existence of correlations between successive applications of the channel on a sequence of quantum systems. In open quantum systems theory memory effects arise dynamically during the time evolution of quantum systems and define non-Markovian dynamics. Here we relate and combine these two different concepts of memory. In particular, we study the interplay between correlations between multiple uses of quantum channels and non-Markovianity as nondivisibility of the t -parametrized family of channels defining the dynamical map.

  3. Memory Effect and Fast Spinodal Decomposition

    CERN Document Server

    Koide, T; Ramos, Rudnei O

    2007-01-01

    We consider the modification of the Cahn-Hilliard equation when a time delay process through a memory function is taken into account. We then study the process of spinodal decomposition in fast phase transitions associated with a conserved order parameter. The introduced memory effect plays an important role to obtain a finite group velocity. Then, we discuss the constraint for the parameters to satisfy causality. The memory effect is seen to affect the dynamics of phase transition at short times and has the effect of delaying, in a significant way, the process of rapid growth of the order parameter that follows a quench into the spinodal region.

  4. Quantum channels and memory effects

    Science.gov (United States)

    Caruso, Filippo; Giovannetti, Vittorio; Lupo, Cosmo; Mancini, Stefano

    2014-10-01

    Any physical process can be represented as a quantum channel mapping an initial state to a final state. Hence it can be characterized from the point of view of communication theory, i.e., in terms of its ability to transfer information. Quantum information provides a theoretical framework and the proper mathematical tools to accomplish this. In this context the notion of codes and communication capacities have been introduced by generalizing them from the classical Shannon theory of information transmission and error correction. The underlying assumption of this approach is to consider the channel not as acting on a single system, but on sequences of systems, which, when properly initialized allow one to overcome the noisy effects induced by the physical process under consideration. While most of the work produced so far has been focused on the case in which a given channel transformation acts identically and independently on the various elements of the sequence (memoryless configuration in jargon), correlated error models appear to be a more realistic way to approach the problem. A slightly different, yet conceptually related, notion of correlated errors applies to a single quantum system which evolves continuously in time under the influence of an external disturbance which acts on it in a non-Markovian fashion. This leads to the study of memory effects in quantum channels: a fertile ground where interesting novel phenomena emerge at the intersection of quantum information theory and other branches of physics. A survey is taken of the field of quantum channels theory while also embracing these specific and complex settings.

  5. Managing Chemotherapy Side Effects: Memory Changes

    Science.gov (United States)

    N ational C ancer I nstitute Managing Chemotherapy Side Effects Memory Changes What is causing these changes? Your doctor will work to find out what is causing these problems. They may be caused by ...

  6. Stress effects on working memory, explicit memory, and implicit memory for neutral and emotional stimuli in healthy men

    Directory of Open Access Journals (Sweden)

    Mathias Luethi

    2009-01-01

    Full Text Available Stress is a strong modulator of memory function. However, memory is not a unitary process and stress seems to exert different effects depending on the memory type under study. Here, we explored the impact of social stress on different aspects of human memory, including tests for explicit memory and working memory (for neutral materials, as well as implicit memory (perceptual priming, contextual priming and classical conditioning for emotional stimuli. A total of 35 young adult male students were randomly assigned to either the stress or the control group, with stress being induced by the Trier Social Stress Test (TSST. Salivary cortisol levels were assessed repeatedly throughout the experiment to validate stress effects. The results support previous evidence indicating complex effects of stress on different types of memory: A pronounced working memory deficit was associated with exposure to stress. No performance differences between groups of stressed and unstressed subjects were observed in verbal explicit memory (but note that learning and recall took place within 1 hour and immediately following stress or in implicit memory for neutral stimuli. Stress enhanced classical conditioning for negative but not positive stimuli. In addition, stress improved spatial explicit memory. These results reinforce the view that acute stress can be highly disruptive for working memory processing. They provide new evidence for the facilitating effects of stress on implicit memory for negative emotional materials. Our findings are discussed with respect to their potential relevance for psychiatric disorders, such as post traumatic stress disorder.

  7. Field Discontinuities and the Memory Effect

    Science.gov (United States)

    Tolish, Alexander; Wald, Robert

    2017-01-01

    The ``memory effect,'' a permanent change in the separation of test particles after the passage of a pulse of gravitational radiation, is a well-defined and fairly well-understood phenomenon in spacetimes with a notion of null infinity. However, many valid questions remain unanswered. For example, how do we define memory in the absence of null infinity? Or, does memory depend on the precise details of the radiation source or just on the source's asymptotic behavior? We believe that such questions are best answered using a simplified, distributional model of memory. If we consider linearized gravity on fixed background spacetimes, we can study the scattering of point particles, which radiate metric perturbations with sharp, step-function wave fronts. These steps correspond to derivative-of-delta-function discontinuities in the curvature, and according to the geodesic deviation equation, it is these discontinuities (and these alone) that contribute to permanent, finite changes in test particle separation-i.e., memory. Using this analysis of field discontinuities (as well as scalar and electromagnetic analogues of gravitational memory) we can isolate the physics of the memory effect from other, background phenomena.

  8. Acute Alcohol Effects on Repetition Priming and Word Recognition Memory with Equivalent Memory Cues

    Science.gov (United States)

    Ray, Suchismita; Bates, Marsha E.

    2006-01-01

    Acute alcohol intoxication effects on memory were examined using a recollection-based word recognition memory task and a repetition priming task of memory for the same information without explicit reference to the study context. Memory cues were equivalent across tasks; encoding was manipulated by varying the frequency of occurrence (FOC) of words…

  9. Mechanocaloric effects in Shape Memory Alloys

    OpenAIRE

    Manosa, Lluis; Planes, Antoni

    2016-01-01

    Shape memory alloys are a class of ferroic materials which undergo a structural (martensitic) transition where the associated ferroic property is a lattice distortion (strain). The sensitiveness of the transition to the conjugated external field (stress), together with the latent heat of the transition gives rise to giant mechanocaloric effects. In non-magnetic shape memory alloys, the lattice distortion is mostly described by a pure shear and the martensitic transition in this family of allo...

  10. Magnonic interferometric switch for multi-valued logic circuits

    Science.gov (United States)

    Balynsky, Michael; Kozhevnikov, Alexander; Khivintsev, Yuri; Bhowmick, Tonmoy; Gutierrez, David; Chiang, Howard; Dudko, Galina; Filimonov, Yuri; Liu, Guanxiong; Jiang, Chenglong; Balandin, Alexander A.; Lake, Roger; Khitun, Alexander

    2017-01-01

    We investigated a possible use of the magnonic interferometric switches in multi-valued logic circuits. The switch is a three-terminal device consisting of two spin channels where input, control, and output signals are spin waves. Signal modulation is achieved via the interference between the source and gate spin waves. We report experimental data on a micrometer scale prototype based on the Y3Fe2(FeO4)3 structure. The output characteristics are measured at different angles of the bias magnetic field. The On/Off ratio of the prototype exceeds 13 dB at room temperature. Experimental data are complemented by the theoretical analysis and the results of micro magnetic simulations showing spin wave propagation in a micrometer size magnetic junction. We also present the results of numerical modeling illustrating the operation of a nanometer-size switch consisting of just 20 spins in the source-drain channel. The utilization of spin wave interference as a switching mechanism makes it possible to build nanometer-scale logic gates, and minimize energy per operation, which is limited only by the noise margin. The utilization of phase in addition to amplitude for information encoding offers an innovative route towards multi-state logic circuits. We describe possible implementation of the three-value logic circuits based on the magnonic interferometric switches. The advantages and shortcomings inherent in interferometric switches are also discussed.

  11. Pitch memory and exposure effects.

    Science.gov (United States)

    Ben-Haim, Moshe Shay; Eitan, Zohar; Chajut, Eran

    2014-02-01

    Recent studies indicate that the ability to represent absolute pitch values in long-term memory, long believed to be the possession of a small minority of trained musicians endowed with "absolute pitch," is in fact shared to some extent by a considerable proportion of the population. The current study examined whether this newly discovered ability affects aspects of music and auditory cognition, particularly pitch learning and evaluation. Our starting points are two well-established premises: (1) frequency of occurrence has an influence on the way we process stimuli; (2) in Western music, some pitches and musical keys are much more frequent than others. Based on these premises, we hypothesize that if absolute pitch values are indeed represented in long-term memory, pitch frequency of occurrence in music would significantly affect cognitive processes, in particular pitch learning and evaluation. Two experiments were designed to test this hypothesis in participants with no absolute pitch, most with little or no musical training. Experiment 1 demonstrated a faster response and a learning advantage for frequent pitches over infrequent pitches in an identification task. In Experiment 2, participants evaluated infrequent pitches as more pleasing than frequent pitches when presented in isolation. These results suggest that absolute pitch representation in memory may play a substantial, hitherto unacknowledged role in auditory (and specifically musical) cognition. PsycINFO Database Record (c) 2014 APA, all rights reserved.

  12. The effect of empathy on eyewitness memory

    Directory of Open Access Journals (Sweden)

    2015-09-01

    Full Text Available Aims: Numerous factors have been identified that can influence eyewitness memory. These factors lead to an increased susceptibility to the misinformation effect, potentially resulting in critical errors in testimony. One other potential influencing factor may be empathy. Empathy is considered as the reactions of an individual to something another person is experiencing. Research has indicated empathy to be a multidimensional construct, combining cognitive and emotional concepts. Empathy has yet to be investigated as an influencing factor, therefore, the current research sought to examine the effect of empathy on eyewitness memory. Method: Participants (n = 60 completed an online survey consisting of a short video, followed by reading a short narrative containing correct and misinformation. One group of participants (N=31 also received an empathy induction. They then completed empathy measures, a cued recall memory test and a recognition memory test. The memory test contained questions relating to the correct and misinformation. Results: Overall there was no difference between groups on general empathy. The empathy induction group had more event related empathy, however, there was no effect of empathy on memory accuracy. For cued recall, participants were more accurate on questions relating to correct (89% information compared to misleading (37% information. For the recognition questions, participants were about as accurate for the correct (63% and misleading (60% information. Conclusions: These findings indicate that feelings of empathy toward the victim of a crime may not improve the accuracy of witness memory. Cued recall results in superior memory performance for correct information, but very poor performance for misleading information. Recognition recall is moderately accurate for both correct and misleading information.

  13. Mesomechanical modeling of shape memory effect

    Science.gov (United States)

    Vokoun, David; Kafka, Vratislav

    1999-06-01

    Shape memory alloys (SMA) are well known materials. There is a lot of technical applications making use of their unique properties. Most of the significant applications are based on use of the thermomechancial properties. Growing number of those applications causes a need for an universal mathematical model with ability to describe all thermomechancial properties of SMA by relatively simple final set of constitutive equations that could be helpful for development of further sophisticated shape memory applications. Unfortunately, a lot of attention has been paid to metallurgical research of shape memory alloys in a few last decades and less attention was dedicated to shape memory modeling. Our model does not claim to be a universal model, but only one contribution to modeling of shape memory effect for binary SMA. The model is adapted for the most applied SMA -- nitinol and is based on the hypothesis that in the course of shape memory effect the distances of first atomic neighbors (Ni-Ti) remain nearly unchanged, whereas the distances of second neighbors (Ti-Ti and Ni-Ni) change substantially. Consequently, we consider some mechanical properties of Ni-substructure and Ti- substructure separately. The mechanical behavior of Ti- substructure is modeled as elastic whereas that of Ni- substructure as elasto-plastic. The resulting relatively simple differential constitutive equations express relationship among internal stress tensors, macroscopic stress tensors, macroscopic strain tensors and temperature.

  14. Similarity effects in visual working memory.

    Science.gov (United States)

    Jiang, Yuhong V; Lee, Hyejin J; Asaad, Anthony; Remington, Roger

    2016-04-01

    Perceptual similarity is an important property of multiple stimuli. Its computation supports a wide range of cognitive functions, including reasoning, categorization, and memory recognition. It is important, therefore, to determine why previous research has found conflicting effects of inter-item similarity on visual working memory. Studies reporting a similarity advantage have used simple stimuli whose similarity varied along a featural continuum. Studies reporting a similarity disadvantage have used complex stimuli from either a single or multiple categories. To elucidate stimulus conditions for similarity effects in visual working memory, we tested memory for complex stimuli (faces) whose similarity varied along a morph continuum. Participants encoded 3 morphs generated from a single face identity in the similar condition, or 3 morphs generated from different face identities in the dissimilar condition. After a brief delay, a test face appeared at one of the encoding locations for participants to make a same/different judgment. Two experiments showed that similarity enhanced memory accuracy without changing the response criterion. These findings support previous computational models that incorporate featural variance as a component of working memory load. They delineate limitations of models that emphasize cortical resources or response decisions.

  15. On the alleged memory-undermining effects of daydreaming.

    Science.gov (United States)

    Otgaar, Henry; Cleere, Colleen; Merckelbach, Harald; Peters, Maarten; Jelicic, Marko; Lynn, Steven Jay

    2016-01-01

    In three experiments, we examined the memory-undermining effects of daydreaming for (un)related stimuli. In Experiments 1 and 2, we tested whether daydreaming fosters forgetting of semantically interrelated material and hence, catalyzes false memory production. In Experiment 3, we examined the memory effects of different daydreaming instructions. In Experiment 1, daydreaming did not undermine correct recall of semantically interrelated words, nor did it affect false memories. In Experiment 2, we again failed to find that daydreaming exerted memory-undermining effects a. In Experiment 3, no memory effects were obtained using different daydreaming instructions. Together, our studies fail to show appreciable memory-undermining effects of daydreaming.

  16. Prevention Education Effects on Fundamental Memory Processes

    Science.gov (United States)

    Ames, Susan L.; Krank, Marvin; Grenard, Jerry L.; Sussman, Steve; Stacy, Alan W.

    2014-01-01

    This study evaluated effects of a key session from a nationally recognized drug abuse prevention program on basic memory processes in 211 high-risk youth in Southern California. In a randomized, between-subject design, the authors manipulated assignment to a Myth and Denial program session and the time of assessment (immediate vs. one-week delay). The authors examined program decay effects on memory accessibility and judgment errors. Those participants exposed to the program session generated more myths and facts from the program than those in the control group, suggesting that even a single program session influenced students’ memory for program information and this was retained at least one week and detectable with indirect tests of memory accessibility. However, consistent with basic research perspectives, participants in the program delayed assessment group erroneously generated more fact-related information from the session to the prompt “It is a myth that_____” than the participants in the program immediate assessment group; that is, they retained more facts as myths. These types of program effects, anticipated by basic memory theory, were not detected with a traditional judgment task in the present sample. The results suggest that basic science approaches offer a novel way of conceptually recasting prevention effects to more completely understand how these effects may operate. Implications for program evaluation and conceptualization are discussed. PMID:22544598

  17. Incorporating Memory Effects in Phase Separation Processes

    CERN Document Server

    Koide, T; Ramos, R O; Ramos, Rudnei O.

    2006-01-01

    We consider the modification of the Cahn-Hilliard equation when a time delay process through a memory function is taken into account. We then study the process of spinodal decomposition in fast phase transitions associated with a conserved order parameter. Finite-time memory effects are seen to affect the dynamics of phase transition at short times and have the effect of delaying, in a significant way, the explosive spinodal decomposition. These effects are important in several systems characterized by fast processes, like nonequilibrium dynamics in the early universe and in relativistic heavy-ion collisions.

  18. Articulation effects in melody recognition memory.

    Science.gov (United States)

    Wee Hun Lim, Stephen; Goh, Winston D

    2013-09-01

    Various surface features-timbre, tempo, and pitch-influence melody recognition memory, but articulation format effects, if any, remain unknown. For the first time, these effects were examined. In Experiment 1, melodies that remained in the same, or appeared in a different but similar, articulation format from study to test were recognized better than were melodies that were presented in a distinct format at test. A similar articulation format adequately induced matching processes to enhance recognition. Experiment 2 revealed that melodies rated as perceptually dissimilar on the basis of the location of the articulation mismatch did not impair recognition performance, suggesting an important boundary condition for articulation format effects on memory recognition-the matching of the memory trace and recognition probe may depend more on the overall proportion, rather than the temporal location, of the mismatch. The present findings are discussed in terms of a global matching advantage hypothesis.

  19. The memory effect for plane gravitational waves

    Science.gov (United States)

    Zhang, P.-M.; Duval, C.; Gibbons, G. W.; Horvathy, P. A.

    2017-09-01

    We give an account of the gravitational memory effect in the presence of the exact plane wave solution of Einstein's vacuum equations. This allows an elementary but exact description of the soft gravitons and how their presence may be detected by observing the motion of freely falling particles. The theorem of Bondi and Pirani on caustics (for which we present a new proof) implies that the asymptotic relative velocity is constant but not zero, in contradiction with the permanent displacement claimed by Zel'dovich and Polnarev. A non-vanishing asymptotic relative velocity might be used to detect gravitational waves through the ;velocity memory effect;, considered by Braginsky, Thorne, Grishchuk, and Polnarev.

  20. Nonvolatile Memory Based on Nonlinear Magnetoelectric Effects

    Science.gov (United States)

    Shen, Jianxin; Cong, Junzhuang; Chai, Yisheng; Shang, Dashan; Shen, Shipeng; Zhai, Kun; Tian, Ying; Sun, Young

    2016-08-01

    The magnetoelectric effects in multiferroics have a great potential in creating next-generation memory devices. We use an alternative concept of nonvolatile memory based, on a type of nonlinear magnetoelectric effects showing a butterfly-shaped hysteresis loop. The principle is to utilize the states of the magnetoelectric coefficient, instead of magnetization, electric polarization, or resistance, to store binary information. Our experiments in a device made of the PMN-PT/Terfenol-D multiferroic heterostructure clearly demonstrate that the sign of the magnetoelectric coefficient can be repeatedly switched between positive and negative by applying electric fields, confirming the feasibility of this principle. This kind of nonvolatile memory has outstanding practical virtues such as simple structure, easy operation in writing and reading, low power, fast speed, and diverse materials available.

  1. Insights into the gravitational wave memory effect

    Science.gov (United States)

    Bieri, Lydia

    2017-01-01

    A major breakthrough of General Relativity (GR) happened in 2015 with LIGO's first detection of gravitational waves. Typical sources for gravitational radiation are mergers of binary black holes, binary neutron stars and core-collapse supernovae. In these processes mass and momenta are radiated away in form of gravitational waves. GR predicts that these waves leave a footprint in the spacetime, that is they change the spacetime permanently, which results in a permanent displacement of test masses. This effect is called the memory. In this talk, I will explore the gravitational wave memory. We will see that there are two types of memory, one going back to Ya. B. Zel'dovich and A. G. Polnarev and one to D. Christodoulou. Then I will discuss recent work including my collaboration with D. Garfinkle, S.-T. Yau, P. Chen, focusing on how neutrinos or electromagnetic fields contribute to the memory effect, and work with D. Garfinkle and N. Yunes on cosmological memory. The author thanks NSF for support by grant DMS-1253149 to The University of Michigan.

  2. Spinach Effects (Amaranthus hybridus on Spatial Memory

    Directory of Open Access Journals (Sweden)

    Intan Leonita

    2015-03-01

    Full Text Available Background: Spatial memory reduction in elderly is predicted to increase up to twice every 20 years. Spinach (Amaranthus hybridus is widely consumed by Indonesian people and is believed to prevent declined spatial memory function. The aim of this study was to determine the effects of spinach on spatial memory in wistar rat induced by diazepam Methods: An experimental study was conducted during the period of October to November 2012 in Pharmacology and Therapy Laboratory, Faculty of Medicine, Universitas Padjadjaran. Twenty five wistar rats were divided into 5 groups; two groups as controls, and 3 groups were given 100, 200, and 400mg/kg BW ethanolic extract of spinach (EESL, respectively. On day 7, group 3, 4, and 5 were given 1 mg/kg BW diazepam injection. Morris water maze tests and calculations of escape latency time (ELT were performed on day 7 and 8. Data were analyzed using analysis of variance (ANOVA and least significance difference (LSD test. Results: On day 7, group 2 experienced acceleration in ELT compared to group 4 and group 5. On day 8, group 2 experienced acceleration in ELT compared to group 3 and group 4. There was no significant increase in spatial memory in group 5 (EESL 400mg/kg BW that due to the use of higher dosage does not always show better results. Conclusions: EESL can prevent impairment of spatial memory with an effective dose of 200 mg/kg BW.

  3. Multi-valued Neutrosophic Sets and its Application in Multi-criteria Decision-making Problems

    Directory of Open Access Journals (Sweden)

    Juan-juan Peng

    2015-12-01

    Full Text Available In recent years, hesitant fuzzy sets and neutrosophic sets have aroused the interest of researchers and have been widely applied to multi-criteria decisionmaking problems. The operations of multi-valued neutrosophic sets are introduced and a comparison method is developed based on related research of hesitant fuzzy sets and intuitionistic fuzzy sets in this paper. Furthermore, some multi-valued neutrosophic number aggregation operators are proposed and the desirable properties are discussed as well. Finally, an approach for multi-criteria decision-making problems was explored applying the aggregation operators. In addition, an example was provided to illustrate the concrete application of the proposed method.

  4. Convergence of Infinite Family of Multivalued Quasi-Nonexpansive Mappings Using Multistep Iterative Processes

    Directory of Open Access Journals (Sweden)

    Renu Chugh

    2014-01-01

    Full Text Available We prove strong and weak convergence results using multistep iterative sequences for countable family of multivalued quasi-nonexpansive mappings by using some conditions in uniformly convex real Banach space. The results presented extended and improved the corresponding result of Zhang et al. (2013, Bunyawat and Suantai (2012, and some others from finite family, one countable family, and two countable families to k-number of countable families of multivalued quasi-nonexpansive mappings. Also we used a numerical example in C++ computational programs to prove that the iterative scheme we used has better rate of convergence than other existing iterative schemes.

  5. Regularity effect in prospective memory during aging

    Directory of Open Access Journals (Sweden)

    Geoffrey Blondelle

    2016-10-01

    Full Text Available Background: Regularity effect can affect performance in prospective memory (PM, but little is known on the cognitive processes linked to this effect. Moreover, its impacts with regard to aging remain unknown. To our knowledge, this study is the first to examine regularity effect in PM in a lifespan perspective, with a sample of young, intermediate, and older adults. Objective and design: Our study examined the regularity effect in PM in three groups of participants: 28 young adults (18–30, 16 intermediate adults (40–55, and 25 older adults (65–80. The task, adapted from the Virtual Week, was designed to manipulate the regularity of the various activities of daily life that were to be recalled (regular repeated activities vs. irregular non-repeated activities. We examine the role of several cognitive functions including certain dimensions of executive functions (planning, inhibition, shifting, and binding, short-term memory, and retrospective episodic memory to identify those involved in PM, according to regularity and age. Results: A mixed-design ANOVA showed a main effect of task regularity and an interaction between age and regularity: an age-related difference in PM performances was found for irregular activities (older < young, but not for regular activities. All participants recalled more regular activities than irregular ones with no age effect. It appeared that recalling of regular activities only involved planning for both intermediate and older adults, while recalling of irregular ones were linked to planning, inhibition, short-term memory, binding, and retrospective episodic memory. Conclusion: Taken together, our data suggest that planning capacities seem to play a major role in remembering to perform intended actions with advancing age. Furthermore, the age-PM-paradox may be attenuated when the experimental design is adapted by implementing a familiar context through the use of activities of daily living. The clinical

  6. Positive effects of subliminal stimulation on memory.

    Science.gov (United States)

    Chakalis, E; Lowe, G

    1992-06-01

    To assess the effect of subliminally embedded auditory material on short-term recall, 60 volunteer subjects undertook a face-name-occupation memory test before and after a 15-min. intervention. They were randomly assigned into three groups (a control group and two experimental groups) and allocated to one of the following conditions: (1) no sound, (2) supraliminal presentation of relaxing music, and (3) subliminal presentation of memory-improvement affirmations embedded in relaxing music. After intervention, only the subliminal group significantly improved their performance on recall of names.

  7. Duffing oscillators: control and memory effects.

    Science.gov (United States)

    Batista, Adriano A; Oliveira, F A; Nazareno, H N

    2008-06-01

    In the first part of this article we study the hysteretic bistable response of Duffing oscillators and show ways to control the switching between stable branches of this nonlinear response. The control mechanism is either applied through a pulse that can be in phase or out of phase with the periodic driving force or through a frequency-modulated driving force. In the second part we show how memory effects in dissipation qualitatively and quantitatively alter the dynamics of Duffing oscillators. We show how memory functions corresponding to different dissipative regimes (diffusion, subdiffusion, and superdiffusion) affect the oscillator. In particular, we obtain universal power laws for the absoption when the driving frequency omega-->0 . For subdiffusive memories the power law exponents nu2 .

  8. Enhancing the production effect in memory.

    Science.gov (United States)

    Quinlan, Chelsea K; Taylor, Tracy L

    2013-01-01

    The production effect is the finding that subsequent memory is better for words that are produced than for words that are not produced. Whereas the current literature demonstrates that reading aloud is the most effective form of production, the distinctiveness account used to explain the production effect predicts that there is nothing special about reading aloud per se: Other forms of vocal production that include an additional distinct element should produce even greater subsequent memory benefits than reading aloud. To test this, we presented participants with study words that they were instructed to read aloud loudly, read aloud, or read silently (Experiment 1); sing, read aloud, or read silently (Experiment 2); and sing, read aloud loudly, read aloud, or read silently (Experiment 3). We observed that both reading items aloud loudly (Experiments 1 and 3) and singing items (Experiments 2 and 3) at study resulted in greater subsequent recognition than reading items aloud in a normal voice; singing had a larger memory benefit than reading aloud loudly (Experiment 3). Our findings support the distinctiveness hypothesis by demonstrating that there are other forms of production, such as singing and reading aloud loudly that have a more pronounced effect on memory than reading aloud.

  9. Sensitivity of negative subsequent memory and task-negative effects to age and associative memory performance.

    Science.gov (United States)

    de Chastelaine, Marianne; Mattson, Julia T; Wang, Tracy H; Donley, Brian E; Rugg, Michael D

    2015-07-01

    The present fMRI experiment employed associative recognition to investigate the relationships between age and encoding-related negative subsequent memory effects and task-negative effects. Young, middle-aged and older adults (total n=136) were scanned while they made relational judgments on visually presented word pairs. In a later memory test, the participants made associative recognition judgments on studied, rearranged (items studied on different trials) and new pairs. Several regions, mostly localized to the default mode network, demonstrated negative subsequent memory effects in an across age-group analysis. All but one of these regions also demonstrated task-negative effects, although there was no correlation between the size of the respective effects. Whereas negative subsequent memory effects demonstrated a graded attenuation with age, task-negative effects declined markedly between the young and the middle-aged group, but showed no further reduction in the older group. Negative subsequent memory effects did not correlate with memory performance within any age group. By contrast, in the older group only, task-negative effects predicted later memory performance. The findings demonstrate that negative subsequent memory and task-negative effects depend on dissociable neural mechanisms and likely reflect distinct cognitive processes. The relationship between task-negative effects and memory performance in the older group might reflect the sensitivity of these effects to variations in amount of age-related neuropathology. This article is part of a Special Issue entitled SI: Memory.

  10. Thermoinduced plastic flow and shape memory effects

    Directory of Open Access Journals (Sweden)

    Xiao Heng

    2011-01-01

    Full Text Available We propose an enhanced form of thermocoupled J2-flow models of finite deformation elastoplasticity with temperature-dependent yielding and hardening behaviour. The thermomechanical constitutive structure of these models is rendered free and explicit in the rigorous sense of thermodynamic consistency. Namely, with a free energy function explicitly introduced in terms of almost any given form of the thermomechanical constitutive functions, the requirements from the second law are identically fulfilled with positive internal dissipation. We study the case when a dependence of yielding and hardening on temperature is given and demonstrate that thermosensitive yielding with anisotropic hardening may give rise to appreciable plastic flow either in a process of heating or in a cyclic process of heating/cooling, thus leading to the findings of one- and two-way thermoinduced plastic flow. We then show that such theoretical findings turn out to be the effects found in shape memory materials, such as one- and two-way memory effects. Thus, shape memory effects may be explained to be thermoinduced plastic flow resulting from thermosensitive yielding and hardening behaviour. These and other relevant facts may suggest that, from a phenomenological standpoint, thermocoupled elastoplastic J2-flow models with thermosensitive yielding and hardening may furnish natural, straightforward descriptions of thermomechanical behaviour of shape memory materials.

  11. Memory effect in balanced Josephson comparators

    Energy Technology Data Exchange (ETDEWEB)

    Ortlepp, Th., E-mail: tortlepp@cismst.de [CiS Research Institute for Micro-Sensor Systems and Photovoltaics, 14 Konrad-Zuse Street, 99099 Erfurt (Germany); Volkmann, M.H., E-mail: mvolkmann@cismst.de [CiS Research Institute for Micro-Sensor Systems and Photovoltaics, 14 Konrad-Zuse Street, 99099 Erfurt (Germany); Yamanashi, Y., E-mail: yamanasi@ynu.ac.jp [Department of Electrical and Computer Engineering, Yokohama National University, 79-5 Tokiwadai, Yokohama 240-8501 (Japan)

    2014-05-15

    Highlights: • Balanced Josephson comparator decisions depend on previous decisions at high frequencies. • The maximum effective data rate is lower than the clock frequency. • Tradeoff between maximum effective data rate and minimum comparator gray-zone. - Abstract: The performance of a balanced Josephson comparator is measured by its gray-zone and its maximum operation frequency. A typical effect at high clock frequencies is the correlation of output bits with their predecessors, the comparator develops a memory. This is undesirable, as it imposes an upper limit on the useful clock frequency at which the comparator can be operated. In this work, we describe and observe experimentally the memory effect of a Josephson comparator and study its influence on the gray zone width and the maximum effective data rate.

  12. Mann Type Implicit Iteration Approximation for Multivalued Mappings in Banach Spaces

    Directory of Open Access Journals (Sweden)

    Chen Rudong

    2010-01-01

    Full Text Available Let be a nonempty compact convex subset of a uniformly convex Banach space and let be a multivalued nonexpansive mapping. For the implicit iterates , , , . We proved that converges strongly to a fixed point of under some suitable conditions. Our results extended corresponding ones and revised a gap in the work of Panyanak (2007.

  13. Eigenvalue for Densely Defined Perturbations of Multivalued Maximal Monotone Operators in Reflexive Banach Spaces

    Directory of Open Access Journals (Sweden)

    Boubakari Ibrahimou

    2013-01-01

    maximal monotone with and . Using the topological degree theory developed by Kartsatos and Quarcoo we study the eigenvalue problem where the operator is a single-valued of class . The existence of continuous branches of eigenvectors of infinite length then could be easily extended to the case where the operator is multivalued and is investigated.

  14. On Variational Inequalities with Multivalued Operators with Semi-Bounded Variation

    CERN Document Server

    Solonoukha, O V

    1997-01-01

    In this paper we explore solvability of steady-state variational inequalities with multivalued operators. Moreover, we are studying the connections between the class of radially semi-continuous operators with semi-bounded variation and classes of pseudo-monotone and monotone mappings, and some properties of this operators.

  15. EXISTENCE AND ALGORITHM OF SOLUTIONS FOR GENERAL MULTIVALUED MIXED IMPLICIT QUASI- VARIATIONAL INEQUALITIES

    Institute of Scientific and Technical Information of China (English)

    曾六川

    2003-01-01

    A new class of general multivalued mixed implicit quasi-variational inequalities in a real Hilbert space was introduced, which includes the known class of generalized mixed implicit quasi-variational inequalities as a special case, introduced and studied by Ding Xieping. The auxiliary variational principle technique was applied to solve this class of general multivalued mixed implicit quasi-variational inequalities. Firstly, a new auxiliary variational inequality with a proper convex, lower semicontinuous, binary functional was defined and a suitable functional was chosen so that its unique minimum point is equivalent to the solution of such an auxiliary variational inequality. Secondly, this auxiliary variational inequality was utilized to construct a new iterative algorithm for computing approximate solutions to general multivalued mixed implicit quasi-variational inequalities. Here, the equivalence guarantees that the algorithm can generate a sequence of approximate solutions.Finally, the existence of solutions and convergence of approximate solutions for general multivalued mixed implicit quasi-variational inequalities are proved. Moreover, the new convergerce criteria for the algorithm were provided. Therefore, the results give an affirmative anwer to the open question raised by M . A. Noor , and extend and improve the earlier and recent results for various variational inequalities and complementarity problems including the corresponding results for mixed variational inequalities, mixed quasi-variational inequalities and quasi-complementarity problems involving the single-valued and set-valued mappings in the recent literature.

  16. Smart polymer fibers with shape memory effect

    Science.gov (United States)

    Ji, Feng Long; Zhu, Yong; Lian Hu, Jin; Liu, Yan; Yeung, Lap-Yan; Dou Ye, Guang

    2006-12-01

    In this study, a series of smart polymer fibers with a shape memory effect were developed. Firstly, a set of shape memory polyurethanes with varying hard-segment content were synthesized. Then, the solutions of the shape memory polyurethanes were spun into fibers through wet spinning. The thin films of the polyurethanes were considered to represent the nature of the polyurethanes. Differential scanning calorimetry tests were performed on both the thin films and the fibers to compare their thermal properties. Wide angle x-ray diffraction and small angle x-ray scattering techniques were applied to investigate the structure of the thin films and the fibers, and the structure change taking place in the spinning process was therefore revealed. The spinning process resulted in the polyurethane molecules being partially oriented in the direction of the fiber axis. The molecular orientation prompted the aggregation of the hard segments and the formation of hard-segment microdomains. The mechanical properties of the fibers were examined through tensile tests. The shape memory effect of the thin films and the fibers was investigated through a series of thermomechanical cyclic tensile tests. It was found that the fibers showed less shape fixity but more shape recovery compared with the thin films. Further investigations revealed that the recovery stress of the fibers was higher than that of the thin films. The smart fibers may exert the recovery force of shape memory polymers to an extreme extent in the direction of the fiber axis and therefore provide a possibility for producing high-performance actuators.

  17. The effect of brumation on memory retention

    Science.gov (United States)

    Wilkinson, Anna; Hloch, Anne; Mueller-Paul, Julia; Huber, Ludwig

    2017-01-01

    Long-term torpor is an adaptive strategy that allows animals to survive harsh winter conditions. However, the impact that prolonged torpor has on cognitive function is poorly understood. Hibernation causes reduced synaptic activity and experiments with mammals reveal that this can have adverse effects on memories formed prior to hibernation. The impact of brumation, the winter dormancy that is observed in ectotherms, on memory remains unknown. The aim of this study was to examine whether an amphibian, the fire salamander (Salamandra salamandra), was able to retain learned spatial information after a period of brumation. Twelve fire salamanders were trained to make a simple spatial discrimination using a T-maze. All subjects learned the initial task. Upon reaching criterion, half of the subjects were placed into brumation for 100 days while the other half served as controls and were maintained under normal conditions. A post-brumation memory retention test revealed that animals from both conditions retained the learned response. Control tests showed that they solved the task using learned information and not olfactory cues. This finding contrasts with much of the mammalian research and suggests that the processes involved in prolonged torpor may have a fundamentally different impact on memory in mammals and amphibians. PMID:28074838

  18. Memory effect of the online user preference

    CERN Document Server

    Hou, Lei; Guo, Qiang; Liu, Jian-Guo

    2014-01-01

    The mechanism of the online user preference evolution is of great significance for understanding the online user behaviors and improving the quality of online services. Since users are allowed to rate on objects in many online systems, ratings can well reflect the users' preference. With two benchmark datasets from online systems, we uncover the memory effect in users' selecting behavior which is the sequence of qualities of selected objects and the rating behavior which is the sequence of ratings delivered by each user. Furthermore, the memory duration is presented to describe the length of a memory, which exhibits the power-law distribution, i.e., the probability of the occurring of long-duration memory is much higher than that of the random case which follows the exponential distribution. We present a preference model in which a Markovian process is utilized to describe the users' selecting behavior, and the rating behavior depends on the selecting behavior. With only one parameter for each of the user's s...

  19. Testing the exclusivity effect in location memory.

    Science.gov (United States)

    Clark, Daniel P A; Dunn, Andrew K; Baguley, Thom

    2013-01-01

    There is growing literature exploring the possibility of parallel retrieval of location memories, although this literature focuses primarily on the speed of retrieval with little attention to the accuracy of location memory recall. Baguley, Lansdale, Lines, and Parkin (2006) found that when a person has two or more memories for an object's location, their recall accuracy suggests that only one representation can be retrieved at a time (exclusivity). This finding is counterintuitive given evidence of non-exclusive recall in the wider memory literature. The current experiment explored the exclusivity effect further and aimed to promote an alternative outcome (i.e., independence or superadditivity) by encouraging the participants to combine multiple representations of space at encoding or retrieval. This was encouraged by using anchor (points of reference) labels that could be combined to form a single strongly associated combination. It was hypothesised that the ability to combine the anchor labels would allow the two representations to be retrieved concurrently, generating higher levels of recall accuracy. The results demonstrate further support for the exclusivity hypothesis, showing no significant improvement in recall accuracy when there are multiple representations of a target object's location as compared to a single representation.

  20. The Generation Effect and Memory

    OpenAIRE

    Rosner, Zachary Alexander

    2012-01-01

    Educators and psychologists have extolled the benefits of active learning techniques such as organizing material, self-explaining, learning through experience, and practicing retrieval for years. Underlying these strategies is the generation effect, an encoding phenomenon in which actively generating rather than passively learning information improves the subsequent retrieval of item information. Despite rather extensive analysis of the generation effect, the processes underlying it are not f...

  1. Magnetic shape memory effect in thin foils

    Science.gov (United States)

    Heczko, Oleg; Soroka, Aleksandr; Hannula, Simo-Pekka

    2008-07-01

    The magnetic shape memory (MSM) effect was observed in Ni-Mn-Ga freestanding thin foils down to 90μm in thickness using top-down approach. The foils were prepared by thinning the bulk crystals exhibiting MSM effect. The effect was evaluated from the magnetization curves. The significant decrease in magnetic field needed to initiate the MSM effect (magnetic field induced strain or martensite structure reorientation) was observed for the studied foils down to μ0H=0.088T or H =70kA/m. Observation suggests that the pinning of twin boundaries on the internal obstacles rather than pinning on surface lowers twin boundaries' mobility.

  2. Memory boosting effect of Citrus limon, Pomegranate and their combinations

    National Research Council Canada - National Science Library

    Riaz, Azra; Khan, Rafeeq Alam; Algahtani, Hussein A

    2014-01-01

    Memory is greatly influenced by factors like food, stress and quality of sleep, hence present study was designed to evaluate the effect of Citrus limon and Pomegranate juices on memory of mice using...

  3. Childhood Chemo May Have Lasting Effects on Memory

    Science.gov (United States)

    ... html Childhood Chemo May Have Lasting Effects on Memory Study found timing of treatment seemed to play ... chemotherapy may have certain types of thinking and memory problems as young adults, a small study suggests. ...

  4. Gender differences in episodic memory and visual working memory including the effects of age.

    Science.gov (United States)

    Pauls, Franz; Petermann, Franz; Lepach, Anja Christina

    2013-01-01

    Analysing the relationship between gender and memory, and examining the effects of age on the overall memory-related functioning, are the ongoing goals of psychological research. The present study examined gender and age group differences in episodic memory with respect to the type of task. In addition, these subgroup differences were also analysed in visual working memory. A sample of 366 women and 330 men, aged between 16 and 69 years of age, participated in the current study. Results indicate that women outperformed men on auditory memory tasks, whereas male adolescents and older male adults showed higher level performances on visual episodic and visual working memory measures. However, the size of gender-linked effects varied somewhat across age groups. Furthermore, results partly support a declining performance on episodic memory and visual working memory measures with increasing age. Although age-related losses in episodic memory could not be explained by a decreasing verbal and visuospatial ability with age, women's advantage in auditory episodic memory could be explained by their advantage in verbal ability. Men's higher level visual episodic memory performance was found to result from their advantage in visuospatial ability. Finally, possible methodological, biological, and cognitive explanations for the current findings are discussed.

  5. Memory-Effect on Acoustic Cavitation

    OpenAIRE

    Yavaṣ, Oğuz; Leiderer, Paul; Park, Hee K.; Grigoropoulos, Costas P.; Poon, Chie C.; Tam, Andrew C.

    1994-01-01

    The formation of bubbles at a liquid-solid interface due to acoustic cavitation depends particularly on the preconditions of the interface. Here, it wiIl be shown that following laser-induced bubble formation at the interface the acoustic cavitation efficiency is strongly enhanced. Optical reflectance measurements reveal that this observed enhancement of acoustic cavitation due to preceding laser-induced bubble formation, which could be termed as memory effect, decays in a few hundred microse...

  6. Algorithmic quantum simulation of memory effects

    Science.gov (United States)

    Alvarez-Rodriguez, U.; Di Candia, R.; Casanova, J.; Sanz, M.; Solano, E.

    2017-02-01

    We propose a method for the algorithmic quantum simulation of memory effects described by integrodifferential evolution equations. It consists in the systematic use of perturbation theory techniques and a Markovian quantum simulator. Our method aims to efficiently simulate both completely positive and nonpositive dynamics without the requirement of engineering non-Markovian environments. Finally, we find that small error bounds can be reached with polynomially scaling resources, evaluated as the time required for the simulation.

  7. Memory consolidation effects on memory stabilization and item integration in older adults.

    Science.gov (United States)

    Brown, Helen; Maylor, Elizabeth A

    2016-11-23

    This study examined the differential effects of aging on consolidation processes that strengthen newly acquired memory traces in veridical form (memory stabilization) versus consolidation processes that are responsible for integrating these memory traces into an existing body of knowledge (item integration). Older adults learned 13 nonwords and were tested on their memory for the nonwords, and on whether these nonwords impacted upon processing of similar-sounding English words immediately and 24 hours later. Participants accurately recognized the nonwords immediately, but showed significant decreases in delayed recognition and recall. In comparison, the nonwords impacted upon processing of similar-sounding words only in the delayed test. Together, these findings suggest that memory consolidation processes may be more evident in item integration than memory stabilization processes for new declarative memories in older adults.

  8. Dissociation and memory fragmentation: Experimental effects on meta-memory but not on actual memory performance.

    NARCIS (Netherlands)

    van den Hout, M.; Kindt, M.

    2003-01-01

    The relation between state dissociation and fragmentary memory was investigated by assessing both actual memory performance and meta-memory. From a sample of 330 normal subjects, 2 subsamples were selected on basis of trait dissociation, as measured by the Dissociative Experience Scale. 20 subjects

  9. Dissociation and memory fragmentation: Experimental effects on meta-memory but not on actual memory performance.

    NARCIS (Netherlands)

    van den Hout, M.; Kindt, M.

    2003-01-01

    The relation between state dissociation and fragmentary memory was investigated by assessing both actual memory performance and meta-memory. From a sample of 330 normal subjects, 2 subsamples were selected on basis of trait dissociation, as measured by the Dissociative Experience Scale. 20 subjects

  10. Joint effects of emotion and color on memory.

    Science.gov (United States)

    Kuhbandner, Christof; Pekrun, Reinhard

    2013-06-01

    Numerous studies have shown that memory is enhanced for emotionally negative and positive information relative to neutral information. We examined whether emotion-induced memory enhancement is influenced by low-level perceptual attributes such as color. Because in everyday life red is often used as a warning signal, whereas green signals security, we hypothesized that red might enhance memory for negative information and green memory for positive information. To capture the signaling function of colors, we measured memory for words standing out from the context by color, and manipulated the color and emotional significance of the outstanding words. Making words outstanding by color strongly enhanced memory, replicating the well-known von Restorff effect. Furthermore, memory for colored words was further increased by emotional significance, replicating the memory-enhancing effect of emotion. Most intriguingly, the effects of emotion on memory additionally depended on color type. Red strongly increased memory for negative words, whereas green strongly increased memory for positive words. These findings provide the first evidence that emotion-induced memory enhancement is influenced by color and demonstrate that different colors can have different functions in human memory.

  11. Memory

    Science.gov (United States)

    ... it has to decide what is worth remembering. Memory is the process of storing and then remembering this information. There are different types of memory. Short-term memory stores information for a few ...

  12. Effects of Methylphenidate on Memory Functions of Adults with ADHD.

    Science.gov (United States)

    Fuermaier, Anselm B M; Tucha, Lara; Koerts, Janneke; Weisbrod, Matthias; Lange, Klaus W; Aschenbrenner, Steffen; Tucha, Oliver

    2016-04-18

    Neuropsychological research on adults with attention deficit hyperactivity disorder (ADHD) revealed considerable impairments in memory functions related to executive control. However, only limited evidence exists supporting the effects of pharmacological treatment using methylphenidate (MPH) on memory functions. The aim of the present study was, therefore, to explore the impact of MPH on various memory functions of adults with ADHD. Thirty-one adults with ADHD treated with MPH, 36 adults with ADHD not-treated with MPH, and 36 healthy individuals were assessed on several aspects of memory, including short-term memory, working memory, retrospective memory, prospective memory, and source memory. Multivariate statistical analyses were applied to compare memory functions between groups. Nonmedicated adults with ADHD showed considerable impairments in memory functions related to executive control. Adults with ADHD treated with MPH showed improved memory functions when compared to nonmedicated patients, but were still impaired when compared to healthy controls. The present study emphasized the severity of memory impairments of adults with ADHD. A pharmacological treatment with MPH appeared to improve memory, but does not normalize functioning. Additional treatment intervention (e.g., cognitive-behavioral therapy) is therefore necessary.

  13. Convergence Theorems for a Common Point of Solutions of Equilibrium and Fixed Point of Relatively Nonexpansive Multivalued Mapping Problems

    Directory of Open Access Journals (Sweden)

    H. Zegeye

    2012-01-01

    Full Text Available We introduce an iterative process which converges strongly to a common point of set of solutions of equilibrium problem and set of fixed points of finite family of relatively nonexpansive multi-valued mappings in Banach spaces.

  14. Spatial Working Memory Effects in Early Visual Cortex

    Science.gov (United States)

    Munneke, Jaap; Heslenfeld, Dirk J.; Theeuwes, Jan

    2010-01-01

    The present study investigated how spatial working memory recruits early visual cortex. Participants were required to maintain a location in working memory while changes in blood oxygen level dependent (BOLD) signals were measured during the retention interval in which no visual stimulation was present. We show working memory effects during the…

  15. Effects of Acute Exercise on Long-Term Memory

    Science.gov (United States)

    Labban, Jeffrey D.; Etnier, Jennifer L.

    2011-01-01

    In this study, we tested the effect of acute exercise on long-term memory, specifically the timing of exercise relative to the memory challenge. We assessed memory via paragraph recall, in which participants listened to two paragraphs (exposure) and recounted them following a 35-min delay. Participants (n = 48) were randomly assigned to one of…

  16. Effects of Acute Exercise on Long-Term Memory

    Science.gov (United States)

    Labban, Jeffrey D.; Etnier, Jennifer L.

    2011-01-01

    In this study, we tested the effect of acute exercise on long-term memory, specifically the timing of exercise relative to the memory challenge. We assessed memory via paragraph recall, in which participants listened to two paragraphs (exposure) and recounted them following a 35-min delay. Participants (n = 48) were randomly assigned to one of…

  17. Twice reverse shape memory effect in CuZnAl shape memory alloy

    Institute of Scientific and Technical Information of China (English)

    李周; 汪明朴; 徐根应; 郭明星

    2004-01-01

    The variations of the shape memory effects in the Cu-13Zn-15Al(mole fraction, %) alloy upon successive heating (the rate of heating is 5 ℃/min) have been studied by means of p-T curve , shape memory effect measurement, optical metallographical observation and X-ray diffraction. The first abnormal reverse shape memory effect occurs when the tested alloy is heated to the temperature below 320 ℃; when it is heated to the temperature between 320 ℃ and 450 ℃, the forward shape memory effect occurs; in the two stages, the shape of the sample remains the same as that in the furnace when it is taken out from the furnace and air-cooled; when the tested alloy is heated to the temperature above 450 ℃, the shape of the sample remains unchanged during heating, but the second reverse shape memory effect occurs after it is air-quenched.

  18. Effect of some anesthetics on memory and exploration.

    Science.gov (United States)

    Valzelli, L; Kozak, W; Skorupska, M

    1988-04-01

    A light ether anesthesia in laboratory mice resulted in the complete drop of their memory retrieval to zero for more than three days after the administration. On the contrary, mice that underwent the exploration test after the light ether anesthesia performed as expected, confirming that impairment of memory does not necessarily reflect on exploratory performance. The effect of some anesthetic drugs was then studied on memory retrieval and exploratory behavior. Within this general framework, the anesthetics here studied all worsen memory retrieval, however without inducing clear and long-lasting amnesic effect comparable to that exerted by ether anesthesia. Contrarily, the classically amnesic drug scopolamine, orally administered, enhances memory retrieval and improves exploration.

  19. No effect of odor-induced memory reactivation during REM sleep on declarative memory stability

    Directory of Open Access Journals (Sweden)

    Maren Jasmin Cordi

    2014-09-01

    Full Text Available Memory reactivations in hippocampal brain areas are critically involved in memory consolidation processes during sleep. In particular, specific firing patterns of hippocampal place cells observed during learning are replayed during subsequent sleep and rest in rodents. In humans, experimentally inducing hippocampal memory reactivations during slow-wave sleep (but not during wakefulness benefits consolidation and immediately stabilizes declarative memories against future interference. Importantly, spontaneous hippocampal replay activity can also be observed during rapid-eye movement (REM sleep and some authors have suggested that replay during REM sleep is related to processes of memory consolidation. However, the functional role of reactivations during REM sleep for memory stability is still unclear. Here, we reactivated memories during REM sleep and examined its consequences for the stability of declarative memories. After three hours of early, slow-wave sleep (SWS rich sleep, 16 healthy young adults learned a 2-D object location task in the presence of a contextual odor. During subsequent REM sleep, participants were either re-exposed to the odor or to an odorless vehicle, in a counterbalanced within subject design. Reactivation was followed by an interference learning task to probe memory stability after awakening. We show that odor-induced memory reactivation during REM sleep does not stabilize memories against future interference. We propose that the beneficial effect of reactivation during sleep on memory stability might be critically linked to processes characterizing SWS including, e.g., slow oscillatory activity, sleep spindles or low cholinergic tone, which are required for a successful redistribution of memories from medial temporal lobe regions to neocortical long-term stores.

  20. Effects of treadmill exercise intensity on spatial working memory and long-term memory in rats.

    Science.gov (United States)

    Wang, Xiao-Qin; Wang, Gong-Wu

    2016-03-15

    Moderate exercise promotes learning and memory. Most studies mainly focused on memory exercise effects of in the ageing and patients. There is lack of quantitative research about effect of regular exercise intensity on different memory types in normal subjects. Present study investigated the effects of different intensities of treadmill exercise on working memory and long-term memory. Fifty female Wistar rats were trained by T-maze delayed spatial alternation (DSA) task with 3 delays (10s, 60s and 300s). Then they got a 30min treadmill exercise for 30days in 4 intensities (control, 0m/min; lower, 15m/min; middle, 20m/min, and higher, 30m/min). Then animals were tested in DSA, passive avoidance and Morris water maze tasks. 1. Exercise increased the neuronal density of hippocampal subregions (CA1, CA3 and dentate gyrus) vs. naïve/control. 2. In DSA task, all groups have similar baseline, lower intensity improved 10s delay accuracy vs. baseline/control; middle and higher intensities improved 300s delay accuracy vs. baseline/control. 3. In water maze learning, all groups successfully found the platform, but middle intensity improved platform field crossing times vs. control in test phase. Present results suggested that treadmill exercise can improve long-term spatial memory and working memory; lower intensity benefits to short-term delayed working memory, and middle or higher intensity benefits to long-term delayed working memory. There was an inverted U dose-effect relationship between exercise intensity and memory performance, but exercise -working memory effect was impacted by delay duration. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Effect of charge memory in organic composites

    Science.gov (United States)

    Belogorokhov, I. A.; Kotova, M. S.; Donskov, A. A.; Dronov, M. A.; Belogorokhova, L. I.

    2016-07-01

    The effect of charge memory in composites based on polymer molecules has been investigated. Resistive switchings in sandwich samples prepared by lamination from commercially available polymers (polystyrene and poly(2,3-dihydrothieno-1,4-dioxine)-poly(styrene sulphonate) are analyzed. It is shown that the characteristic switching times in the composite samples reach several nanoseconds and the number of switchings exceeds 106. Switchings are observed in electric fields much below the breakdown threshold, which indicates the absence of destructive processes in the polymer.

  2. The effect of mild acute stress during memory consolidation on emotional recognition memory.

    Science.gov (United States)

    Corbett, Brittany; Weinberg, Lisa; Duarte, Audrey

    2017-08-21

    Stress during consolidation improves recognition memory performance. Generally, this memory benefit is greater for emotionally arousing stimuli than neutral stimuli. The strength of the stressor also plays a role in memory performance, with memory performance improving up to a moderate level of stress and thereafter worsening. As our daily stressors are generally minimal in strength, we chose to induce mild acute stress to determine its effect on memory performance. In the current study, we investigated if mild acute stress during consolidation improves memory performance for emotionally arousing images. To investigate this, we had participants encode highly arousing negative, minimally arousing negative, and neutral images. We induced stress using the Montreal Imaging Stress Task (MIST) in half of the participants and a control task to the other half of the participants directly after encoding (i.e. during consolidation) and tested recognition 48 hours later. We found no difference in memory performance between the stress and control group. We found a graded pattern among confidence, with responders in the stress group having the least amount of confidence in their hits and controls having the most. Across groups, we found highly arousing negative images were better remembered than minimally arousing negative or neutral images. Although stress did not affect memory accuracy, responders, as defined by cortisol reactivity, were less confident in their decisions. Our results suggest that the daily stressors humans experience, regardless of their emotional affect, do not have adverse effects on memory. Copyright © 2017. Published by Elsevier Inc.

  3. Quaternary Galois field adder based all-optical multivalued logic circuits.

    Science.gov (United States)

    Chattopadhyay, Tanay; Taraphdar, Chinmoy; Roy, Jitendra Nath

    2009-08-01

    Galois field (GF) algebraic expressions have been found to be promising choices for reversible and quantum implementation of multivalued logic. For the first time to our knowledge, we developed GF(4) adder multivalued (four valued) logic circuits in an all-optical domain. The principle and possibilities of an all-optical GF(4) adder circuit are described. The theoretical model is presented and verified through numerical simulation. The quaternary inverter, successor, clockwise cycle, and counterclockwise cycle gates are proposed with the help of the all-optical GF(4) adder circuit. In this scheme different quaternary logical states are represented by different polarized light. A terahertz optical asymmetric demultiplexer interferometric switch plays an important role in this scheme.

  4. Design of Multi-Valued Quaternary Based Analog-to-Digital Converter

    Directory of Open Access Journals (Sweden)

    A. H.M.Z. Alam

    2009-01-01

    Full Text Available Problem statement: The design of multi-valued quaternary based Analog-to-Digital Converter (ADC circuit was presented. The ADC generates multi-valued logic outputs rather than the conventional binary output system to overall reduction in circuit complexity and size. Approach: Design was implemented using pipeline ADC architecture and was simulated using model parameters based on standard 0.13 µm CMOS process. Results: Performance analysis of the design showed desirable performance parameters in terms of response, low power consumption, and a sampling rate of 10 MHz at a supply voltage of 1.3V was achieved. Conclusion/Recommendations: The ADC design was suitable for the needs of mixed-signal integrated circuit design and can be implemented as a conversion circuit for systems based on multiple-valued logic design.

  5. Topological fixed point theory for singlevalued and multivalued mappings and applications

    CERN Document Server

    Ben Amar, Afif

    2016-01-01

    This is a monograph covering topological fixed point theory for several classes of single and multivalued maps. The authors begin by presenting basic notions in locally convex topological vector spaces. Special attention is then devoted to weak compactness, in particular to the theorems of Eberlein–Šmulian, Grothendick and Dunford–Pettis. Leray–Schauder alternatives and eigenvalue problems for decomposable single-valued nonlinear weakly compact operators in Dunford–Pettis spaces are considered, in addition to some variants of Schauder, Krasnoselskii, Sadovskii, and Leray–Schauder type fixed point theorems for different classes of weakly sequentially continuous operators on general Banach spaces. The authors then proceed with an examination of Sadovskii, Furi–Pera, and Krasnoselskii fixed point theorems and nonlinear Leray–Schauder alternatives in the framework of weak topologies and involving multivalued mappings with weakly sequentially closed graph. These results are formulated in terms of ax...

  6. Differential effects of modafinil on memory in naïve and memory-impaired rats.

    Science.gov (United States)

    Garcia, Vanessa Athaíde; Souza de Freitas, Betânia; Busato, Stefano Boemler; D'avila Portal, Bernardo Chaves; Piazza, Francisco Correa; Schröder, Nadja

    2013-12-01

    Modafinil is a wake-promoting drug and has been approved for the treatment of excessive daytime sleepiness in narcolepsy and obstructive sleep apnea. Modafinil was shown to improve learning and memory in rodents, and to reverse memory deficits induced by sleep deprivation or stress. However, depending on the memory paradigm used, modafinil might also impair memory. We aimed to investigate the effects of modafinil on memory consolidation and retrieval for object recognition and inhibitory avoidance in naïve adult rats. We also investigated whether acute or chronic administration of modafinil would reverse memory deficits induced by iron overload, a model of memory impairment related to neurodegenerative disorders. Adult naïve rats received modafinil (0.0, 0.75, 7.5 or 75 mg/kg) either immediately after training or 1 h prior to testing in object recognition or inhibitory avoidance. Iron-treated rats received modafinil immediately after training in object recognition. In order to investigate the effects of chronic modafinil, iron-treated rats received daily injections of modafinil for 17 days, and 24 h later they were trained in object recognition or inhibitory avoidance. Acute modafinil does not affect memory consolidation or retrieval in naive rats. A single injection of modafinil at the highest dose was able to recover recognition memory in iron-treated rats. Chronic modafinil completely recovered iron-induced recognition memory and emotional memory deficits. Additional preclinical and clinical studies are necessary in order to support the applicability of modafinil in recovering memory impairment associated with neurodegenerative disorders.

  7. Gestalt Effects in Visual Working Memory.

    Science.gov (United States)

    Kałamała, Patrycja; Sadowska, Aleksandra; Ordziniak, Wawrzyniec; Chuderski, Adam

    2017-01-01

    Four experiments investigated whether conforming to Gestalt principles, well known to drive visual perception, also facilitates the active maintenance of information in visual working memory (VWM). We used the change detection task, which required the memorization of visual patterns composed of several shapes. We observed no effects of symmetry of visual patterns on VWM performance. However, there was a moderate positive effect when a particular shape that was probed matched the shape of the whole pattern (the whole-part similarity effect). Data support the models assuming that VWM encodes not only particular objects of the perceptual scene but also the spatial relations between them (the ensemble representation). The ensemble representation may prime objects similar to its shape and thereby boost access to them. In contrast, the null effect of symmetry relates the fact that this very feature of an ensemble does not yield any useful additional information for VWM.

  8. Common Fixed Point of Multivalued Generalized φ-Weak Contractive Mappings

    Directory of Open Access Journals (Sweden)

    Behzad Djafari Rouhani

    2010-01-01

    Full Text Available Fixed point and coincidence results are presented for multivalued generalized φ-weak contractive mappings on complete metric spaces, where φ:[0,+∞→[0,+∞ is a lower semicontinuous function with φ(0=0 and φ(t>0 for all t>0. Our results extend previous results by Zhang and Song (2009, as well as by Rhoades (2001, Nadler (1969, and Daffer and Kaneko (1995.

  9. On Wiener-Poisson Type Multivalued Stochastic Differential Equations with Non-Lipschitz Coefficients

    Institute of Scientific and Technical Information of China (English)

    Jing WU

    2013-01-01

    In this paper,we prove local uniqueness for multivalued stochastic differential equations with Poisson jumps.Then existence and uniqueness of global solutions is obtained under the conditions that the coefficients satisfy locally Lipschitz continuity and one-sided linear growth of b.Moreover,we also prove the Markov property of the solution and the existence of invariant measures for the corresponding transition semigroup.

  10. Mann Type Implicit Iteration Approximation for Multivalued Mappings in Banach Spaces

    Directory of Open Access Journals (Sweden)

    Huimin He

    2010-01-01

    Full Text Available Let K be a nonempty compact convex subset of a uniformly convex Banach space E and let T be a multivalued nonexpansive mapping. For the implicit iterates x0∈K, xn=αnxn-1+(1-αnyn, yn∈Txn, n≥1. We proved that {xn} converges strongly to a fixed point of T under some suitable conditions. Our results extended corresponding ones and revised a gap in the work of Panyanak (2007.

  11. A Piecewise Linear Fitting Technique for Multivalued Two-dimensional Paths

    Directory of Open Access Journals (Sweden)

    V.M. Jimenez-Fernandez

    2013-10-01

    Full Text Available This paper presents a curve-fitting technique for multivalued two-dimensional piecewise-linear paths. The proposed method is based on a decomposed formulation of the canonical piecewise linear model description of Chua and Kang. The path is treated as a parametric system of two position equations (x(k, y(k, where k is an artificial parameter to map each variable (x and y into an independent k-domain.

  12. Claudio Moraga a passion for multi-valued logic and soft computing

    CERN Document Server

    Allende-Cid, Héctor

    2017-01-01

    The book is an authoritative collection of contributions by leading experts on the topics of fuzzy logic, multi-valued logic and neural network. Originally written as an homage to Claudio Moraga, seen by his colleagues as an example of concentration, discipline and passion for science, the book also represents a timely reference guide for advance students and researchers in the field of soft computing, and multiple-valued logic. .

  13. Identifying and characterizing the effects of nutrition on hippocampal memory.

    Science.gov (United States)

    Monti, Jim M; Baym, Carol L; Cohen, Neal J

    2014-05-01

    In this review we provide evidence linking relational memory to the hippocampus, as well as examples of sensitive relational memory tasks that may help characterize the subtle effects of nutrition on learning and memory. Research into dietary effects on cognition is in its nascent stages, and many studies have cast a wide net with respect to areas of cognition to investigate. However, it may be that nutrition will have a disproportionate effect on particular cognitive domains. Thus, researchers interested in nutrition-cognition interactions may wish to apply a more targeted approach when selecting cognitive domains. We suggest that hippocampus-based relational memory may be extraordinarily sensitive to the effects of nutrition. The hippocampus shows unique plastic capabilities, making its structure and function responsive to an array of lifestyle factors and environmental conditions, including dietary intake. A major function of the hippocampus is relational memory, defined as learning and memory for the constituent elements and facts that comprise events. Here we identify several sensitive tests of relational memory that may be used to examine what may be subtle effects of nutrition on hippocampus and memory. We then turn to the literature on aerobic exercise and cognition to provide examples of translational research programs that have successfully applied this targeted approach centering on the hippocampus and sensitive relational memory tools. Finally, we discuss selected findings from animal and human research on nutrition and the hippocampus and advocate for the role of relational memory tasks in future research.

  14. Memory Effects and Transport Coefficients for Non-Newtonian Fluids

    CERN Document Server

    Kodama, T

    2008-01-01

    We discuss the roles of viscosity in relativistic fluid dynamics from the point of view of memory effects. Depending on the type of quantity to which the memory effect is applied, different terms appear in higher order corrections. We show that when the memory effect applies on the extensive quantities, the hydrodynamic equations of motion become non-singular. We further discuss the question of memory effect in the derivation of transport coefficients from a microscopic theory. We generalize the application of the Green-Kubo-Nakano (GKN) to calculate transport coefficients in the framework of projection operator formalism, and derive the general formula when the fluid is non-Newtonian.

  15. Assessing the aging effect on auditory-verbal memory by Persian version of dichotic auditory verbal memory test

    Directory of Open Access Journals (Sweden)

    Zahra Shahidipour

    2014-01-01

    Conclusion: Based on the obtained results, significant reduction in auditory memory was seen in aged group and the Persian version of dichotic auditory-verbal memory test, like many other auditory verbal memory tests, showed the aging effects on auditory verbal memory performance.

  16. Some New Concepts of Shape Memory Effect of Polymers

    Directory of Open Access Journals (Sweden)

    Abbas Tcharkhtchi

    2014-04-01

    Full Text Available In this study some new concepts regarding certain aspects related to shape memory polymers are presented. A blend of polylactic acid (PLA (80% and polybutylene succinate (PBS (20% was prepared first by extrusion, then by injection molding to obtain the samples. Tensile, stress-relaxation and recovery tests were performed on these samples at 70 °C. The results indicated that the blend can only regain 24% of its initial shape. It was shown that, this partial shape memory effect could be improved by successive cycles of shape memory tests. After a fourth cycle, the blend is able to regain 82% of its shape. These original results indicated that a polymer without (or with partial shape memory effect may be transformed into a shape memory polymer without any chemical modification. In this work, we have also shown the relationship between shape memory and property memory effect. Mono and multi-frequency DMA (dynamic mechanical analyzer tests on virgin and 100% recovered samples of polyurethane (PU revealed that the polymer at the end of the shape memory tests regains 100% of its initial form without regaining some of its physical properties like glass transition temperature, tensile modulus, heat expansion coefficient and free volume fraction. Shape memory (with and without stress-relaxation tests were performed on the samples in order to show the role of residual stresses during recovery tests. On the basis of the results we have tried to show the origin of the driving force responsible for shape memory effect.

  17. Vantage perspective during encoding: The effects on phenomenological memory characteristics.

    Science.gov (United States)

    Mooren, Nora; Krans, Julie; Näring, Gérard W B; Moulds, Michelle L; van Minnen, Agnes

    2016-05-01

    The vantage perspective from which a memory is retrieved influences the memory's emotional impact, intrusiveness, and phenomenological characteristics. This study tested whether similar effects are observed when participants were instructed to imagine the events from a specific perspective. Fifty student participants listened to a verbal report of car-accidents and visualized the scenery from either a field or observer perspective. There were no between-condition differences in emotionality of memories and the number of intrusions, but imagery experienced from a relative observer perspective was rated as less self-relevant. In contrast to earlier studies on memory retrieval, vantage perspective influenced phenomenological memory characteristics of the memory representation such as sensory details, and ratings of vividness and distancing of the memory. However, vantage perspective is most likely not a stable phenomenological characteristic itself. Implications and suggestions for future research are discussed.

  18. The effects of emotion on memory for music and vocalisations.

    Science.gov (United States)

    Aubé, William; Peretz, Isabelle; Armony, Jorge L

    2013-01-01

    Music is a powerful tool for communicating emotions which can elicit memories through associative mechanisms. However, it is currently unknown whether emotion can modulate memory for music without reference to a context or personal event. We conducted three experiments to investigate the effect of basic emotions (fear, happiness, and sadness) on recognition memory for music, using short, novel stimuli explicitly created for research purposes, and compared them with nonlinguistic vocalisations. Results showed better memory accuracy for musical clips expressing fear and, to some extent, happiness. In the case of nonlinguistic vocalisations we confirmed a memory advantage for all emotions tested. A correlation between memory accuracy for music and vocalisations was also found, particularly in the case of fearful expressions. These results confirm that emotional expressions, particularly fearful ones, conveyed by music can influence memory as has been previously shown for other forms of expressions, such as faces and vocalisations.

  19. Stress effects on memory : An update and integration

    NARCIS (Netherlands)

    Schwabe, Lars; Joëls, Marian; Roozendaal, Benno; Wolf, Oliver T.; Oitzl, Melly S.

    2012-01-01

    It is well known that stressful experiences may affect learning and memory processes. Less clear is the exact nature of these stress effects on memory: both enhancing and impairing effects have been reported. These opposite effects may be explained if the different time courses of stress hormone, in

  20. Stress effects on memory: an update and integration

    NARCIS (Netherlands)

    Schwabe, L.; Joels, M.; Roozendaal, B.; Wolf, O.T.; Oitzl, M.S.

    2012-01-01

    It is well known that stressful experiences may affect learning and memory processes. Less clear is the exact nature of these stress effects on memory: both enhancing and impairing effects have been reported. These opposite effects may be explained if the different time courses of stress hormone, in

  1. Stress effects on memory : An update and integration

    NARCIS (Netherlands)

    Schwabe, Lars; Joëls, Marian; Roozendaal, Benno; Wolf, Oliver T.; Oitzl, Melly S.

    2012-01-01

    It is well known that stressful experiences may affect learning and memory processes. Less clear is the exact nature of these stress effects on memory: both enhancing and impairing effects have been reported. These opposite effects may be explained if the different time courses of stress hormone, in

  2. Memory effect from spinning unbound binaries

    CERN Document Server

    De Vittori, Lorenzo; Gupta, Anuradha; Jetzer, Philippe

    2014-01-01

    We present a recently developed prescription to obtain ready-to-use gravitational wave (GW) polarization states for spinning compact binaries on hyperbolic orbits. We include leading order spin-orbit interactions, invoking 1.5PN-accurate quasi-Keplerian parametrization for the radial part of the orbital dynamics. We also include radiation reaction effects on $h_+$ and $h_{\\times}$ during the interaction. In the GW signals from spinning binaries there is evidence of the memory effect in both polarizations, in contrast to the non-spinning case, where only the cross polarizations exhibits non-vanishing amplitudes at infinite time. We also compute 1PN-accurate GW polarization states for non-spinning compact binaries in unbound orbits in a fully parametric way, and compare them with existing waveforms.

  3. Transformation Volume Effects on Shape Memory Alloys

    Directory of Open Access Journals (Sweden)

    Anna Kosogor

    2013-07-01

    Full Text Available It is generally accepted that the martensitic transformations (MTs in the shape memory alloys (SMAs are mainly characterized by the shear deformation of the crystal lattice that arises in the course of MT, while a comparatively small volume change during MT is considered as the secondary effect, which can be disregarded when the basic characteristics of MTs and functional properties of SMAs are analyzed. This point of view is a subject to change nowadays due to the new experimental and theoretical findings. The present article elucidates (i the newly observed physical phenomena in different SMAs in their relation to the volume effect of MT; (ii the theoretical analysis of the aforementioned volume-related phenomena.

  4. Explanation of the memory effect in argon

    Directory of Open Access Journals (Sweden)

    Marković Vidosav

    2005-01-01

    Full Text Available Memory effect - the long time variation of the electrical breakdown time delay on the relaxation time td (τ was observed in argon 24 hours after relaxation times and explained by the long-lived metastable states remaining from the preceding glow. However, the quenching processes reducing the effective lifetime of metastable states several orders of magnitude below that relevant for the time scale of observation were neglected. By applying approximate gas phase models it was found that the early afterglow kinetics up to hundreds of milliseconds is dominated by the decay of molecular argon ions Ar2+ and the approximate value of their ambipolar diffusion coefficient is determined. After that, nitrogen atoms present as impurities and recombined on the cathode surface and/or field emission determine the breakdown time delay down to the cosmic rays and natural radioactivity level.

  5. Suppression effects on musical and verbal memory.

    Science.gov (United States)

    Schendel, Zachary A; Palmer, Caroline

    2007-06-01

    Three experiments contrasted the effects of articulatory suppression on recognition memory for musical and verbal sequences. In Experiment 1, a standard/comparison task was employed, with digit or note sequences presented visually or auditorily while participants remained silent or produced intermittent verbal suppression (saying "the") or musical suppression (singing "la"). Both suppression types decreased performance by equivalent amounts, as compared with no suppression. Recognition accuracy was lower during suppression for visually presented digits than during that for auditorily presented digits (consistent with phonological loop predictions), whereas accuracy was equivalent for visually presented notes and auditory tones. When visual interference filled the retention interval in Experiment 2, performance with visually presented notes but not digits was impaired. Experiment 3 forced participants to translate visually presented music sequences by presenting comparison sequences auditorily. Suppression effects for visually presented music resembled those for digits only when the recognition task required sensory translation of cues.

  6. Digitally manipulating memory: effects of doctored videos and imagination in distorting beliefs and memories.

    Science.gov (United States)

    Nash, Robert A; Wade, Kimberley A; Lindsay, D Stephen

    2009-06-01

    In prior research on false autobiographical beliefs and memories, subjects have been asked to imagine fictional events and have been exposed to false evidence that indicates that the fictional events occurred. But what are the relative contributions of imagination and false evidence toward false belief and memory construction? In the present study, subjects observed and copied various simple actions; then they viewed doctored videos that suggested that they had performed extra actions and they imagined performing some of those and some other actions. Subjects returned 2 weeks later for a memory test. False evidence or imagination alone was often sufficient to cause belief and memory distortions; in combination, they appeared to have additive or even superadditive effects. The results bear on the mechanisms underlying false beliefs and memories, and we propose legal and clinical applications of these findings.

  7. Expectancy effects in memory for melodies.

    Science.gov (United States)

    Schmuckler, M A

    1997-12-01

    Two experiments explored the relation between melodic expectancy and melodic memory. In Experiment 1, listeners rated the degree to which different endings confirmed their expectations for a set of melodies. After providing these expectancy ratings, listeners received a recognition memory test in which they discriminated previously heard melodies from new melodies. Recognition memory in this task positively correlated with perceived expectancy, and was related to the estimated tonal coherence of these melodies. Experiment 2 extended these results, demonstrating better recognition memory for high expectancy melodies, relative to medium and low expectancy melodies. This experiment also observed asymmetrical memory confusions as a function of perceived expectancy. These findings fit with a model of musical memory in which schematically central events are better remembered than schematically peripheral events.

  8. Effects of non-invasive brain stimulation on associative memory.

    Science.gov (United States)

    Matzen, Laura E; Trumbo, Michael C; Leach, Ryan C; Leshikar, Eric D

    2015-10-22

    Associative memory refers to remembering the association between two items, such as a face and a name. It is a crucial part of daily life, but it is also one of the first aspects of memory performance that is impacted by aging and by Alzheimer's disease. Evidence suggests that transcranial direct current stimulation (tDCS) can improve memory performance, but few tDCS studies have investigated its impact on associative memory. In addition, no prior study of the effects of tDCS on memory performance has systematically evaluated the impact of tDCS on different types of memory assessments, such as recognition and recall tests. In this study, we measured the effects of tDCS on associative memory performance in healthy adults, using both recognition and recall tests. Participants studied face-name pairs while receiving either active (30 min, 2 mA) or sham (30 min, 0.1 mA) stimulation with the anode placed at F9 and the cathode placed on the contralateral upper arm. Participants in the active stimulation group performed significantly better on the recall test than participants in the sham group, recalling 50% more names, on average, and making fewer recall errors. However, the two groups did not differ significantly in terms of their performance on the recognition memory test. This investigation provides evidence that stimulation at the time of study improves associative memory encoding, but that this memory benefit is evident only under certain retrieval conditions.

  9. Communication: Memory effects and active Brownian diffusion

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Pulak K. [Department of Chemistry, Presidency University, Kolkata 700073 (India); Li, Yunyun, E-mail: yunyunli@tongji.edu.cn [Center for Phononics and Thermal Energy Science, Tongji University, Shanghai 200092 (China); Marchegiani, Giampiero [Dipartimento di Fisica, Università di Camerino, I-62032 Camerino (Italy); Marchesoni, Fabio [Center for Phononics and Thermal Energy Science, Tongji University, Shanghai 200092 (China); Dipartimento di Fisica, Università di Camerino, I-62032 Camerino (Italy)

    2015-12-07

    A self-propelled artificial microswimmer is often modeled as a ballistic Brownian particle moving with constant speed aligned along one of its axis, but changing direction due to random collisions with the environment. Similarly to thermal noise, its angular randomization is described as a memoryless stochastic process. Here, we speculate that finite-time correlations in the orientational dynamics can affect the swimmer’s diffusivity. To this purpose, we propose and solve two alternative models. In the first one, we simply assume that the environmental fluctuations governing the swimmer’s propulsion are exponentially correlated in time, whereas in the second one, we account for possible damped fluctuations of the propulsion velocity around the swimmer’s axis. The corresponding swimmer’s diffusion constants are predicted to get, respectively, enhanced or suppressed upon increasing the model memory time. Possible consequences of this effect on the interpretation of the experimental data are discussed.

  10. Effects of aging and education on false memory.

    Science.gov (United States)

    Lee, Yuh-Shiow; Lee, Chia-Lin; Yang, Hua-Te

    2012-01-01

    This study examined the effects of aging and education on participants' false memory for words that were not presented. Three age groups of participants with either a high or low education level were asked to study lists of semantically related words. Both age and education were found to affect veridical and false memory, as indicated in the recall and recognition of the studied word and nonstudied lures. A low education level had a negative effect on memory performance for both young and middle-aged adults. Older adults with a high level of education had a higher level of false memory than those with a lower education level. The results of this study are discussed in terms of the importance of education on false memory and mechanisms that create false memory of words in older adults.

  11. Word Length Effects in Long-Term Memory

    Science.gov (United States)

    Tehan, Gerald; Tolan, Georgina Anne

    2007-01-01

    The word length effect has been a central feature of theorising about immediate memory. The notion that short-term memory traces rapidly decay unless refreshed by rehearsal is based primarily upon the finding that serial recall for short words is better than that for long words. The decay account of the word length effect has come under pressure…

  12. Word Length Effects in Long-Term Memory

    Science.gov (United States)

    Tehan, Gerald; Tolan, Georgina Anne

    2007-01-01

    The word length effect has been a central feature of theorising about immediate memory. The notion that short-term memory traces rapidly decay unless refreshed by rehearsal is based primarily upon the finding that serial recall for short words is better than that for long words. The decay account of the word length effect has come under pressure…

  13. Mechanocaloric effects in shape memory alloys.

    Science.gov (United States)

    Mañosa, Lluís; Planes, Antoni

    2016-08-13

    Shape memory alloys (SMA) are a class of ferroic materials which undergo a structural (martensitic) transition where the associated ferroic property is a lattice distortion (strain). The sensitiveness of the transition to the conjugated external field (stress), together with the latent heat of the transition, gives rise to giant mechanocaloric effects. In non-magnetic SMA, the lattice distortion is mostly described by a pure shear and the martensitic transition in this family of alloys is strongly affected by uniaxial stress, whereas it is basically insensitive to hydrostatic pressure. As a result, non-magnetic alloys exhibit giant elastocaloric effects but negligible barocaloric effects. By contrast, in a number of magnetic SMA, the lattice distortion at the martensitic transition involves a volume change in addition to the shear strain. Those alloys are affected by both uniaxial stress and hydrostatic pressure and they exhibit giant elastocaloric and barocaloric effects. The paper aims at providing a critical survey of available experimental data on elastocaloric and barocaloric effects in magnetic and non-magnetic SMA.This article is part of the themed issue 'Taking the temperature of phase transitions in cool materials'.

  14. Radiation Effects of Commercial Resistive Random Access Memories

    Science.gov (United States)

    Chen, Dakai; LaBel, Kenneth A.; Berg, Melanie; Wilcox, Edward; Kim, Hak; Phan, Anthony; Figueiredo, Marco; Buchner, Stephen; Khachatrian, Ani; Roche, Nicolas

    2014-01-01

    We present results for the single-event effect response of commercial production-level resistive random access memories. We found that the resistive memory arrays are immune to heavy ion-induced upsets. However, the devices were susceptible to single-event functional interrupts, due to upsets from the control circuits. The intrinsic radiation tolerant nature of resistive memory makes the technology an attractive consideration for future space applications.

  15. Memory effect in composites of liquid crystal and silica aerosil

    Energy Technology Data Exchange (ETDEWEB)

    Relaix, Sabrina; Leheny, Robert L.; Reven, Linda; Sutton, Mark (McGill); (JHU)

    2012-02-07

    Aerosil silica nanoparticles dispersed in a liquid crystal (LC) possess the interesting property of keeping memory of an electric- or magnetic-field-induced orientation. Two types of memory have been identified: thermally erasable memory arising from the pinning of defect lines versus a 'permanent' memory where the orientation persists even after thermal cycling the samples up to the isotropic phase. To address the source of the latter type of memory, solid-state nuclear magnetic resonance spectroscopy and conventional x-ray diffraction (XRD) were first combined to characterize the LC orientational order as a function of multiple in-field temperature cycles. Microbeam XRD was then performed on aligned gels of different concentrations to gain knowledge of the structural properties at the origin of the memory effect. No detectable anisotropy of the gel or significant breaking of silica strands with heating ruled out the formation of an anisotropic silica network as the source of the permanent memory as previously proposed. Instead, support for a role of the surface memory effect, well known for planar substrates, in stabilizing the permanent memory was deduced from 'training' of the composites, that is, optimizing the orientational order through the thermal in-field cycling. The ability to train the composites is inversely proportional to the strength of the random-field disorder. The portion of thermally erasable memory also decreases as the silica density increases. We propose that the permanent memory originates from the surface memory effect operating at points of intersection in the silica network. These areas, where the LC is strongly confined with conflicted surface interactions, are trained to achieve an optimized orientation and subsequently act as sites from which the LC orientational order regrows after zero-field thermal cycling up to the isotropic phase.

  16. Differential Effects of Alcohol Consumption Behaviours on Working Memory Processes

    Directory of Open Access Journals (Sweden)

    Shaunak Sanjay Deshpande

    2015-11-01

    Full Text Available Alcohol exposure in a clinical population impairs working memory. In order to establish the effects of alcohol on working memory in typical young adults, this study looked at their alcohol consumption behaviours and how they predict working memory. A battery of cognitive tasks and a recreational drug use questionnaire assessed working memory and alcohol consumption of 100 participants. The results revealed that alcohol abstinence predicted set-shifting, verbal executive, phonological loop, spatial and visual working memory performance, which is consistent with current literature. I surmise that the recent use of alcohol plays a role in working memory impairments and offer novel findings that the length of abstinence plays a role in the cognitive recovery of young adults.

  17. Effects of Aging and Education on False Memory

    Science.gov (United States)

    Lee, Yuh-Shiow; Lee, Chia-Lin; Yang, Hua-Te

    2012-01-01

    This study examined the effects of aging and education on participants' false memory for words that were not presented. Three age groups of participants with either a high or low education level were asked to study lists of semantically related words. Both age and education were found to affect veridical and false memory, as indicated in the…

  18. The Production Effect in Memory: A Prominent Mnemonic in Children

    Science.gov (United States)

    Icht, Michal; Mama, Yaniv

    2015-01-01

    The "Production Effect" (PE) refers to a memory advantage for items studied aloud over items studied silently. Thus, vocalizing may serve as a mnemonic that can be used to assist learners in improving their memory for new concepts. Although many other types of mnemonic have been suggested in the literature, the PE seems especially…

  19. Sentence Complexity and Working Memory Effects in Ambiguity Resolution

    Science.gov (United States)

    Kim, Ji Hyon; Christianson, Kiel

    2013-01-01

    Two self-paced reading experiments using a paraphrase decision task paradigm were performed to investigate how sentence complexity contributed to the relative clause (RC) attachment preferences of speakers of different working memory capacities (WMCs). Experiment 1 (English) showed working memory effects on relative clause processing in both…

  20. Effects of Music Notation Reinforcement on Aural Memory for Melodies

    Science.gov (United States)

    Buonviri, Nathan

    2015-01-01

    The purpose of this study was to investigate effects of music notation reinforcement on aural memory for melodies. Participants were 41 undergraduate and graduate music majors in a within-subjects design. Experimental trials tested melodic memory through a sequence of target melodies, distraction melodies, and matched and unmatched answer choices.…

  1. Time-dependent effects of cardiovascular exercise on memory

    DEFF Research Database (Denmark)

    Roig, Marc; Thomas, Richard; Mang, Cameron S

    2016-01-01

    We present new evidence supporting the hypothesis that the effects of cardiovascular exercise on memory can be regulated in a time-dependent manner. When the exercise stimulus is temporally coupled with specific phases of the memory formation process, a single bout of cardiovascular exercise may ...

  2. Effects of Music Notation Reinforcement on Aural Memory for Melodies

    Science.gov (United States)

    Buonviri, Nathan

    2015-01-01

    The purpose of this study was to investigate effects of music notation reinforcement on aural memory for melodies. Participants were 41 undergraduate and graduate music majors in a within-subjects design. Experimental trials tested melodic memory through a sequence of target melodies, distraction melodies, and matched and unmatched answer choices.…

  3. Memory effect in ac plasma displays

    Science.gov (United States)

    Szlenk, K.; Obuchowicz, E.

    1993-10-01

    The bistable or `memory' mode of operation of an ac plasma display panel is presented. The difference between dc and ac plasma panel operation from the point of view of memory function is discussed. The graphic ac plasma display with thin film Cr-Cu-Cr electrodes was developed in OBREP and its basic parameters are described. It consists of 36 X 59 picture elements, its outer dimensions are: 76 X 52 mm2 and the screen size is: 49 X 30 mm2. The different dielectric glass materials were applied as dielectric layers and the influence of the properties of these materials on display parameters and memory function was investigated.

  4. Multivalued fundamental diagrams of traffic flow in the kinetic Fokker-Planck limit

    CERN Document Server

    Visconti, Giuseppe; Puppo, Gabriella; Tosin, Andrea

    2016-01-01

    Starting from interaction rules based on two levels of stochasticity we study the influence of the microscopic dynamics on the macroscopic properties of vehicular flow. In particular, we study the qualitative structure of the resulting flux-density and speed-density diagrams for different choices of the desired speeds. We are able to recover multivalued diagrams as a result of the existence of a one-parameter family of stationary distributions, whose expression is analytically found by means of a Fokker-Planck approximation of the initial Boltzmann-type model.

  5. Some fixed point theorems for multivalued maps in ordered Banach spaces and applications

    Directory of Open Access Journals (Sweden)

    Zhai Chengbo

    2005-01-01

    Full Text Available The existence of maximal and minimal fixed points for various set-valued operators is discussed. This paper presents some new fixed point theorems in ordered Banach spaces. A necessary and sufficient condition for the existence of the fixed point to a class of multivalued maps has been obtained. The uniqueness of the positive fixed point has been discussed. The results extend and improve the corresponding results. As an application, we utilize the results to study the existence and uniqueness of positive fixed points for a class of convex operators. In the end, we give a simple application to certain integral equations.

  6. Periodic and almost periodic solutions for multi-valued differential equations in Banach spaces

    Directory of Open Access Journals (Sweden)

    E. Hanebaly

    2000-03-01

    Full Text Available It is known that for $omega$-periodic differential equations of monotonous type, in uniformly convex Banach spaces, the existence of a bounded solution on ${Bbb R}^+$ is equivalent to the existence of an omega-periodic solution (see Haraux [5] and Hanebaly [7, 10]. It is also known that if the Banach space is strictly convex and the equation is almost periodic and of monotonous type, then the existence of a continuous solution with a precompact range is equivalent to the existence of an almost periodic solution (see Hanebaly [8]. In this note we want to generalize the results above for multi-valued differential equations.

  7. Convergence Theorems for Infinite Family of Multivalued Quasi-Nonexpansive Mappings in Uniformly Convex Banach Spaces

    Directory of Open Access Journals (Sweden)

    Aunyarat Bunyawat

    2012-01-01

    Full Text Available We introduce an iterative method for finding a common fixed point of a countable family of multivalued quasi-nonexpansive mapping {Ti} in a uniformly convex Banach space. We prove that under certain control conditions, the iterative sequence generated by our method is an approximating fixed point sequence of each Ti. Some strong convergence theorems of the proposed method are also obtained for the following cases: all Ti are continuous and one of Ti is hemicompact, and the domain K is compact.

  8. Fixed Point Theorems for Suzuki Generalized Nonexpansive Multivalued Mappings in Banach Spaces

    Directory of Open Access Journals (Sweden)

    Abkar A

    2010-01-01

    Full Text Available In the first part of this paper, we prove the existence of common fixed points for a commuting pair consisting of a single-valued and a multivalued mapping both satisfying the Suzuki condition in a uniformly convex Banach space. In this way, we generalize the result of Dhompongsa et al. (2006. In the second part of this paper, we prove a fixed point theorem for upper semicontinuous mappings satisfying the Suzuki condition in strictly spaces; our result generalizes a recent result of Domínguez-Benavides et al. (2009.

  9. Fixed Point Theorems for Suzuki Generalized Nonexpansive Multivalued Mappings in Banach Spaces

    Directory of Open Access Journals (Sweden)

    A. Abkar

    2010-01-01

    Full Text Available In the first part of this paper, we prove the existence of common fixed points for a commuting pair consisting of a single-valued and a multivalued mapping both satisfying the Suzuki condition in a uniformly convex Banach space. In this way, we generalize the result of Dhompongsa et al. (2006. In the second part of this paper, we prove a fixed point theorem for upper semicontinuous mappings satisfying the Suzuki condition in strictly L(τ spaces; our result generalizes a recent result of Domínguez-Benavides et al. (2009.

  10. Existence Solutions of Vector Equilibrium Problems and Fixed Point of Multivalued Mappings

    Directory of Open Access Journals (Sweden)

    Kanokwan Sitthithakerngkiet

    2013-01-01

    Full Text Available Let K be a nonempty compact convex subset of a topological vector space. In this paper-sufficient conditions are given for the existence of x∈K such that F(T∩VEP(F≠∅, where F(T is the set of all fixed points of the multivalued mapping T and VEP(F is the set of all solutions for vector equilibrium problem of the vector-valued mapping F. This leads us to generalize and improve some existence results in the recent references.

  11. Shape Memory Effect Actuators from Chlorides Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Shape Change Technologies is developing a radical new technique for the fabrication of Shape Memory alloys, such as TiNi and its ternary alloys of Hf, Zr, and Cu....

  12. MULTI-VALUED TOTALLY QUASI-φ-ASYMPTOTICALLY NONEXPANSIVE SEMI-GROUPS AND STRONG CONVERGENCE THEOREMS IN BANACH SPACES

    Institute of Scientific and Technical Information of China (English)

    Shisheng ZHANG; Lin WANG; Yunhe ZHAO

    2013-01-01

    The purpose of this article is first to introduce the concept of multi-valued totally Quasi-φ-asymptotically nonexpansive semi-groups,which contains many kinds of semigroups as its special cases,and then to modify the Halpern-Mann-type iteration algorithm for multi-valued totally Quasi-φ-asymptotically nonexpansive semi-groups to have the strong convergence under a limit condition only in the framework of Banach spaces.The results presented in this article improve and extend the corresponding results announced by many authors recently.

  13. Criteria for the Single-Valued Metric Generalized Inverses of Multi-Valued Linear Operators in Banach Spaces

    Institute of Scientific and Technical Information of China (English)

    Yu Wen WANG; Jian ZHANG; Yun An CUI

    2012-01-01

    Let X,Y be Banach spaces and M be a linear subspace in X × Y ={{x,y}|x ∈ X,y ∈ Y}.We may view M as a multi-valued linear operator from X to Y by taking M(x) ={y|{x,y} ∈ M}.In this paper,we give several criteria for a single-valued operator from Y to X to be the metric generalized inverse of the multi-valued linear operator M.The principal tool in this paper is also the generalized orthogonal decomposition theorem in Banach spaces.

  14. Gist memory in the unconscious-thought effect.

    Science.gov (United States)

    Abadie, Marlène; Waroquier, Laurent; Terrier, Patrice

    2013-07-01

    The unconscious-thought effect (UTE) occurs when people are better able to make complex decisions after a period of distraction rather than immediately or after a period of conscious deliberation. This finding has often been interpreted as evidence of unconscious thinking. In two experiments, we provided the first evidence that the UTE is accompanied by enhanced memory for the gist of decision-relevant attributes and demonstrated that the cognitive demands of a distraction task moderate its effect on decision making and gist memory. It was only following a low-demand distraction task that participants chose the best alternative more often and displayed enhanced gist memory for decision-relevant attributes. These findings suggest that the UTE occurs only if cognitive resources are available and that it is accompanied by enhanced organization of information in memory, as shown by the increase in gist memory.

  15. Memory color effect induced by familiarity of brand logos.

    Directory of Open Access Journals (Sweden)

    Atsushi Kimura

    Full Text Available BACKGROUND: When people are asked to adjust the color of familiar objects such as fruits until they appear achromatic, the subjective gray points of the objects are shifted away from the physical gray points in a direction opposite to the memory color (memory color effect. It is still unclear whether the discrepancy between memorized and actual colors of objects is dependent on the familiarity of the objects. Here, we conducted two experiments in order to examine the relationship between the degree of a subject's familiarity with objects and the degree of the memory color effect by using logographs of food and beverage companies. METHODS AND FINDINGS: In Experiment 1, we measured the memory color effects of logos which varied in terms of their familiarity (high, middle, or low. Results demonstrate that the memory color effect occurs only in the high-familiarity condition, but not in the middle- and low-familiarity conditions. Furthermore, there is a positive correlation between the memory color effect and the actual number of domestic stores of the brand. In Experiment 2, we assessed the semantic association between logos and food/beverage names by using a semantic priming task to elucidate whether the memory color effect of logos relates to consumer brand cognition, and found that the semantic associations between logos and food/beverage names in the high-familiarity brands were stronger than those in the low-familiarity brands only when the logos were colored correctly, but not when they were appropriately or inappropriately colored, or achromatic. CONCLUSION: The current results provide behavioral evidence of the relationship between the familiarity of objects and the memory color effect and suggest that the memory color effect increases with the familiarity of objects, albeit not constantly.

  16. Effects of cues to event segmentation on subsequent memory.

    Science.gov (United States)

    Gold, David A; Zacks, Jeffrey M; Flores, Shaney

    2017-01-01

    To remember everyday activity it is important to encode it effectively, and one important component of everyday activity is that it consists of events. People who segment activity into events more adaptively have better subsequent memory for that activity, and event boundaries are remembered better than event middles. The current study asked whether intervening to improve segmentation by cuing effective event boundaries would enhance subsequent memory for events. We selected a set of movies that had previously been segmented by a large sample of observers and edited them to provide visual and auditory cues to encourage segmentation. For each movie, cues were placed either at event boundaries or event middles, or the movie was left unedited. To further support the encoding of our everyday event movies, we also included post-viewing summaries of the movies. We hypothesized that cuing at event boundaries would improve memory, and that this might reduce age differences in memory. For both younger and older adults, we found that cuing event boundaries improved memory-particularly for the boundaries that were cued. Cuing event middles also improved memory, though to a lesser degree; this suggests that imposing a segmental structure on activity may facilitate memory encoding, even when segmentation is not optimal. These results provide evidence that structural cuing can improve memory for everyday events in younger and older adults.

  17. The rotational memory effect of a multimode fiber

    CERN Document Server

    Amitonova, L V; Pinkse, P W H

    2015-01-01

    We demonstrate the rotational memory effect in a multimode fiber. Rotating the incident wavefront around the fiber core axis leads to a rotation of the resulting pattern of the fiber output without significant changes in the resulting speckle pattern. The rotational memory effect can be exploited for non-invasive imaging or ultrafast high-resolution scanning through a multimode fiber. Our experiments demonstrate this effect over a full range of angles in two experimental configurations.

  18. Effects of Cortisol on Reconsolidation of Reactivated Fear Memories.

    Science.gov (United States)

    Drexler, Shira Meir; Merz, Christian J; Hamacher-Dang, Tanja C; Tegenthoff, Martin; Wolf, Oliver T

    2015-12-01

    The return of conditioned fear after successful extinction (eg, following exposure therapy) is a significant problem in the treatment of anxiety disorders and posttraumatic stress disorder (PTSD). Targeting the reconsolidation of fear memories may allow a more lasting effect as it intervenes with the original memory trace. Indeed, several pharmacological agents and behavioral interventions have been shown to alter (enhance, impair, or otherwise update) the reconsolidation of reactivated memories of different types. Cortisol is a stress hormone and a potent modulator of learning and memory, yet its effects on fear memory reconsolidation are unclear. To investigate whether cortisol intervenes with the reconsolidation of fear memories in healthy males and how specific this effect might be, we built a 3-day reconsolidation design with skin conductance response (SCR) as a measure of conditioned fear: Fear acquisition on day 1; reactivation/no-reactivation of one conditioned stimulus and pharmacological intervention on day 2; extinction learning followed by reinstatement and reinstatement test on day 3. The groups differed only in the experimental manipulation on day 2: Reactivation+Cortisol Group, Reactivation+Placebo Group, or No-reactivation+Cortisol Group. Our results revealed an enhancing effect of cortisol on reconsolidation of the reactivated memory. The effect was highly specific, strengthening only the memory of the reactivated conditioned stimulus and not the non-reactivated one. Our findings are in line with previous findings showing an enhancing effect of behavioral stress on the reconsolidation of other types of memories. These results have implications for the understanding and treatment of anxiety disorders and PTSD.

  19. Differential effects of arousal in positive and negative autobiographical memories.

    Science.gov (United States)

    Ford, Jaclyn Hennessey; Addis, Donna Rose; Giovanello, Kelly S

    2012-01-01

    Autobiographical memories are characterised by a range of emotions and emotional reactions. Recent research has demonstrated that differences in emotional valence (positive vs. negative emotion) and arousal (the degree of emotional intensity) differentially influence the retrieved memory narrative. Although the mnemonic effects of valence and arousal have both been heavily studied, it is currently unclear whether the effects of emotional arousal are equivalent for positive and negative autobiographical events. In the current study, multilevel models were used to examine differential effects of emotional valence and arousal on the richness of autobiographical memory retrieval both between and within subjects. Thirty-four young adults were asked to retrieve personal autobiographical memories associated with popular musical cues and to rate the valence, arousal and richness of these events. The multilevel analyses identified independent influences of valence and intensity upon retrieval characteristics at the within- and between-subject levels. In addition, the within-subject interactions between valence and arousal highlighted differential effects of arousal for positive and negative memories. These findings have important implications for future studies of emotion and memory, highlighting the importance of considering both valence and arousal when examining the role emotion plays in the richness of memory representation.

  20. 多值半流的吸引子在随机扰动下的上半连续性%Upper semi-continuity of attractors for multivalued semi-flow under random perturbation

    Institute of Scientific and Technical Information of China (English)

    李挺; 刘曾荣

    2006-01-01

    In this paper the upper semi-continuity of global attractors for multivalued semi-flows under random perturbation was studied. First, the existence of random attractors for multivalued random semi-flows was considered, then it was proved that the global attractors for multivalue semi-flows are the upper semi-continuity under random perturbation. This result can be used in the ntmerical approximation of multivalued semi-flows and non-autonomous perturbation of multivalued semi-flows.Key words random attractor, upper semi-continuity, absorbing set.

  1. Effects of timbre and tempo change on memory for music.

    Science.gov (United States)

    Halpern, Andrea R; Müllensiefen, Daniel

    2008-09-01

    We investigated the effects of different encoding tasks and of manipulations of two supposedly surface parameters of music on implicit and explicit memory for tunes. In two experiments, participants were first asked to either categorize instrument or judge familiarity of 40 unfamiliar short tunes. Subsequently, participants were asked to give explicit and implicit memory ratings for a list of 80 tunes, which included 40 previously heard. Half of the 40 previously heard tunes differed in timbre (Experiment 1) or tempo (Experiment 2) in comparison with the first exposure. A third experiment compared similarity ratings of the tunes that varied in timbre or tempo. Analysis of variance (ANOVA) results suggest first that the encoding task made no difference for either memory mode. Secondly, timbre and tempo change both impaired explicit memory, whereas tempo change additionally made implicit tune recognition worse. Results are discussed in the context of implicit memory for nonsemantic materials and the possible differences in timbre and tempo in musical representations.

  2. Working memory capacity predicts the beneficial effect of selective memory retrieval.

    Science.gov (United States)

    Schlichting, Andreas; Aslan, Alp; Holterman, Christoph; Bäuml, Karl-Heinz T

    2015-01-01

    Selective retrieval of some studied items can both impair and improve recall of the other items. This study examined the role of working memory capacity (WMC) for the two effects of memory retrieval. Participants studied an item list consisting of predefined target and nontarget items. After study of the list, half of the participants performed an imagination task supposed to induce a change in mental context, whereas the other half performed a counting task which does not induce such context change. Following presentation of a second list, memory for the original list's target items was tested, either with or without preceding retrieval of the list's nontarget items. Consistent with previous work, preceding nontarget retrieval impaired target recall in the absence of the context change, but improved target recall in its presence. In particular, there was a positive relationship between WMC and the beneficial, but not the detrimental effect of memory retrieval. On the basis of the view that the beneficial effect of memory retrieval reflects context-reactivation processes, the results indicate that individuals with higher WMC are better able to capitalise on retrieval-induced context reactivation than individuals with lower WMC.

  3. Memory Effects on Movement Behavior in Animal Foraging.

    Directory of Open Access Journals (Sweden)

    Chloe Bracis

    Full Text Available An individual's choices are shaped by its experience, a fundamental property of behavior important to understanding complex processes. Learning and memory are observed across many taxa and can drive behaviors, including foraging behavior. To explore the conditions under which memory provides an advantage, we present a continuous-space, continuous-time model of animal movement that incorporates learning and memory. Using simulation models, we evaluate the benefit memory provides across several types of landscapes with variable-quality resources and compare the memory model within a nested hierarchy of simpler models (behavioral switching and random walk. We find that memory almost always leads to improved foraging success, but that this effect is most marked in landscapes containing sparse, contiguous patches of high-value resources that regenerate relatively fast and are located in an otherwise devoid landscape. In these cases, there is a large payoff for finding a resource patch, due to size, value, or locational difficulty. While memory-informed search is difficult to differentiate from other factors using solely movement data, our results suggest that disproportionate spatial use of higher value areas, higher consumption rates, and consumption variability all point to memory influencing the movement direction of animals in certain ecosystems.

  4. Memory Effects on Movement Behavior in Animal Foraging.

    Science.gov (United States)

    Bracis, Chloe; Gurarie, Eliezer; Van Moorter, Bram; Goodwin, R Andrew

    2015-01-01

    An individual's choices are shaped by its experience, a fundamental property of behavior important to understanding complex processes. Learning and memory are observed across many taxa and can drive behaviors, including foraging behavior. To explore the conditions under which memory provides an advantage, we present a continuous-space, continuous-time model of animal movement that incorporates learning and memory. Using simulation models, we evaluate the benefit memory provides across several types of landscapes with variable-quality resources and compare the memory model within a nested hierarchy of simpler models (behavioral switching and random walk). We find that memory almost always leads to improved foraging success, but that this effect is most marked in landscapes containing sparse, contiguous patches of high-value resources that regenerate relatively fast and are located in an otherwise devoid landscape. In these cases, there is a large payoff for finding a resource patch, due to size, value, or locational difficulty. While memory-informed search is difficult to differentiate from other factors using solely movement data, our results suggest that disproportionate spatial use of higher value areas, higher consumption rates, and consumption variability all point to memory influencing the movement direction of animals in certain ecosystems.

  5. Effects of Methylphenidate on Memory Functions of Adults with ADHD

    NARCIS (Netherlands)

    Fuermaier, Anselm B M; Tucha, Lara; Koerts, Janneke; Weisbrod, Matthias; Lange, Klaus W; Aschenbrenner, Steffen; Tucha, Oliver

    2017-01-01

    Neuropsychological research on adults with attention deficit hyperactivity disorder (ADHD) revealed considerable impairments in memory functions related to executive control. However, only limited evidence exists supporting the effects of pharmacological treatment using methylphenidate (MPH) on memo

  6. Effects of Methylphenidate on Memory Functions of Adults with ADHD

    NARCIS (Netherlands)

    Fuermaier, Anselm B M; Tucha, Lara; Koerts, Janneke; Weisbrod, Matthias; Lange, Klaus W; Aschenbrenner, Steffen; Tucha, Oliver

    2016-01-01

    Neuropsychological research on adults with attention deficit hyperactivity disorder (ADHD) revealed considerable impairments in memory functions related to executive control. However, only limited evidence exists supporting the effects of pharmacological treatment using methylphenidate (MPH) on memo

  7. Effects of clorazepate, diazepam, lorazepam, and placebo on human memory.

    Science.gov (United States)

    Healey, M; Pickens, R; Meisch, R; McKenna, T

    1983-12-01

    Healthy adults (N = 10) were given oral doses of lorazepam (1 and 2 mg), diazepam (5 and 10 mg), clorazepate (7.5 and 15 mg), or placebo and tested 30, 60, 90, and 120 minutes later on a word-recall memory task. All subjects received each drug dose once and placebo twice in randomized order at weekly intervals. Testing was double-blind. Lorazepam was found to have a significantly greater effect on memory than placebo. Diazepam and clorazepate did not differ significantly from placebo in their effect on word recall. High doses of lorazepam produced more pronounced memory effects than did low doses; neither diazepam nor clorazepate was found to exert a dose-related effect on memory.

  8. Effects of memory training on the subjective memory functioning and mental health of older adults: a meta-analysis.

    Science.gov (United States)

    Floyd, M; Scogin, F

    1997-03-01

    The effectiveness of memory training on the subjective memory functioning and mental health of older adults was examined in a meta-analysis. Effect sizes indicated that memory training led to improved subjective memory functioning (d+2 = .19), but the magnitude of the improvement was less than that obtained on objective memory measures (d+2 = .66) in the meta-analysis of P. Verhaeghen, A. Marcoen, and L. Goossens (1992). However, no differences in effectiveness were found among mnemonic training, expectancy modification, or placebo procedures such as unstructured practice. Improvement of subjective memory functioning was enhanced by including pretraining in skills such as the use of imagery and by including interventions to improve participants' attitudes toward the effects of aging on memory functioning.

  9. Glucocorticoid therapy-induced memory deficits: acute versus chronic effects.

    Science.gov (United States)

    Coluccia, Daniel; Wolf, Oliver T; Kollias, Spyros; Roozendaal, Benno; Forster, Adrian; de Quervain, Dominique J-F

    2008-03-26

    Conditions with chronically elevated glucocorticoid levels are usually associated with declarative memory deficits. Considerable evidence suggests that long-term glucocorticoid exposure may cause cognitive impairment via cumulative and long-lasting influences on hippocampal function and morphology. However, because elevated glucocorticoid levels at the time of retention testing are also known to have direct impairing effects on memory retrieval, it is possible that such acute hormonal influences on retrieval processes contribute to the memory deficits found with chronic glucocorticoid exposure. To investigate this issue, we examined memory functions and hippocampal volume in 24 patients with rheumatoid arthritis who were treated either chronically (5.3 +/- 1.0 years, mean +/- SE) with low to moderate doses of prednisone (7.5 +/- 0.8 mg, mean +/- SE) or without glucocorticoids. In both groups, delayed recall of words learned 24 h earlier was assessed under conditions of either elevated or basal glucocorticoid levels in a double-blind, placebo-controlled crossover design. Although the findings in this patient population did not provide evidence for harmful effects of a history of chronic prednisone treatment on memory performance or hippocampal volume per se, acute prednisone administration 1 h before retention testing to either the steroid or nonsteroid group impaired word recall. Thus, these findings indicate that memory deficits observed under chronically elevated glucocorticoid levels result, at least in part, from acute and reversible glucocorticoid effects on memory retrieval.

  10. Stress effects on memory: an update and integration.

    Science.gov (United States)

    Schwabe, Lars; Joëls, Marian; Roozendaal, Benno; Wolf, Oliver T; Oitzl, Melly S

    2012-08-01

    It is well known that stressful experiences may affect learning and memory processes. Less clear is the exact nature of these stress effects on memory: both enhancing and impairing effects have been reported. These opposite effects may be explained if the different time courses of stress hormone, in particular catecholamine and glucocorticoid, actions are taken into account. Integrating two popular models, we argue here that rapid catecholamine and non-genomic glucocorticoid actions interact in the basolateral amygdala to shift the organism into a 'memory formation mode' that facilitates the consolidation of stressful experiences into long-term memory. The undisturbed consolidation of these experiences is then promoted by genomic glucocorticoid actions that induce a 'memory storage mode', which suppresses competing cognitive processes and thus reduces interference by unrelated material. Highlighting some current trends in the field, we further argue that stress affects learning and memory processes beyond the basolateral amygdala and hippocampus and that stress may pre-program subsequent memory performance when it is experienced during critical periods of brain development.

  11. Effect of background music on auditory-verbal memory performance

    OpenAIRE

    Sona Matloubi; Ali Mohammadzadeh; Zahra Jafari; Alireza Akbarzade Baghban

    2014-01-01

    Background and Aim: Music exists in all cultures; many scientists are seeking to understand how music effects cognitive development such as comprehension, memory, and reading skills. More recently, a considerable number of neuroscience studies on music have been developed. This study aimed to investigate the effects of null and positive background music in comparison with silence on auditory-verbal memory performance.Methods: Forty young adults (male and female) with normal hearing, aged betw...

  12. Training to Enhance Adult Memory (TEAM): an investigation of the effectiveness of a memory training program with older adults.

    Science.gov (United States)

    Fairchild, J Kaci; Scogin, F R

    2010-04-01

    Prior research examining the effectiveness of memory enhancement programs targeting both objective and subjective memory has yielded results with varying degrees of success. The current investigation aimed to contribute to the present body of memory training literature through the evaluation of an in-home memory enhancement program for older adults. Fifty-three community-dwelling older adults were assigned to either a memory enhancement condition or a minimal social support condition. Those in the memory enhancement condition had significant improvement in remembering names with faces and not misplacing household objects. Additionally, those in the memory enhancement condition also reported being more content with their memory, having fewer lapses in memory, greater use of mnemonic strategies, and were less bothered by memory complaints. Regression analyses indicated that neither levels of positive nor negative affect were predictive of participants' objective and subjective memory at post-treatment. Results of these analyses provide support for the use of memory enhancement programs to improve older adults' ability to keep track of items, remember names and faces, and to also feel better about their memory ability.

  13. The effect of cannabis use on memory function: an update

    Directory of Open Access Journals (Sweden)

    Schoeler T

    2013-01-01

    Full Text Available Tabea Schoeler, Sagnik BhattacharyyaDepartment of Psychosis Studies, King's College London, Institute of Psychiatry, London, UKAbstract: Investigating the effects of cannabis use on memory function appears challenging. While early observational investigations aimed to elucidate the longer-term effects of cannabis use on memory function in humans, findings remained equivocal and pointed to a pattern of interacting factors impacting on the relationship between cannabis use and memory function, rather than a simple direct effect of cannabis. Only recently, a clearer picture of the chronic and acute effects of cannabis use on memory function has emerged once studies have controlled for potential confounding factors and started to investigate the acute effects of delta-9-tetrahydrocannabinol (Δ9-THC and cannabidiol (CBD, the main ingredients in the extract of the cannabis plant in pharmacological challenge experiments. Relatively consistent findings have been reported regarding the acute impairments induced by a single dose of Δ9-THC on verbal and working memory. It is unclear whether they may persist beyond the intoxication state. In the long-term, these impairments seem particularly likely to manifest and may also persist following abstinence if regular and heavy use of cannabis strains high in Δ9-THC is started at an early age. Although still at an early stage, studies that employed advanced neuroimaging techniques have started to model the neural underpinnings of the effects of cannabis use and implicate a network of functional and morphological alterations that may moderate the effects of cannabis on memory function. Future experimental and epidemiological studies that take into consideration individual differences, particularly previous cannabis history and demographic characteristics, but also the precise mixture of the ingredients of the consumed cannabis are necessary to clarify the magnitude and the mechanisms by which cannabis

  14. Stress and Memory: Behavioral Effects and Neurobiological Mechanisms

    Directory of Open Access Journals (Sweden)

    Carmen Sandi

    2007-01-01

    Full Text Available Stress is a potent modulator of learning and memory processes. Although there have been a few attempts in the literature to explain the diversity of effects (including facilitating, impairing, and lack of effects described for the impact of stress on memory function according to single classification criterion, they have proved insufficient to explain the whole complexity of effects. Here, we review the literature in the field of stress and memory interactions according to five selected classifying factors (source of stress, stressor duration, stressor intensity, stressor timing with regard to memory phase, and learning type in an attempt to develop an integrative model to understand how stress affects memory function. Summarizing on those conditions in which there was enough information, we conclude that high stress levels, whether intrinsic (triggered by the cognitive challenge or extrinsic (induced by conditions completely unrelated to the cognitive task, tend to facilitate Pavlovian conditioning (in a linear-asymptotic manner, while being deleterious for spatial/explicit information processing (which with regard to intrinsic stress levels follows an inverted U-shape effect. Moreover, after reviewing the literature, we conclude that all selected factors are essential to develop an integrative model that defines the outcome of stress effects in memory processes. In parallel, we provide a brief review of the main neurobiological mechanisms proposed to account for the different effects of stress in memory function. Glucocorticoids were found as a common mediating mechanism for both the facilitating and impairing actions of stress in different memory processes and phases. Among the brain regions implicated, the hippocampus, amygdala, and prefrontal cortex were highlighted as critical for the mediation of stress effects.

  15. The Effect of Contextual Organization on Spatial Memory of Middle Aged and Older Adults.

    Science.gov (United States)

    Waddell, Kathryn J.; Rogoff, Barbara

    Although age-related memory differences in adulthood occur in a variety of memory tasks, most of these tasks represent uncommon memory demands. An investigation of everyday memory demands explored the effect of contextual organization on memory performance of middle aged (N=20) and older (N=20) women. Tasks involved reconstruction of spatial…

  16. Memory effects in attenuation and amplification quantum processes

    Science.gov (United States)

    Lupo, Cosmo; Giovannetti, Vittorio; Mancini, Stefano

    2010-09-01

    With increasing communication rates via quantum channels, memory effects become unavoidable whenever the use rate of the channel is comparable to the typical relaxation time of the channel environment. We introduce a model of a bosonic memory channel, describing correlated noise effects in quantum-optical processes via attenuating or amplifying media. To study such a channel model, we make use of a proper set of collective field variables, which allows us to unravel the memory effects, mapping the n-fold concatenation of the memory channel to a unitarily equivalent, direct product of n single-mode bosonic channels. We hence estimate the channel capacities by relying on known results for the memoryless setting. Our findings show that the model is characterized by two different regimes, in which the cross correlations induced by the noise among different channel uses are either exponentially enhanced or exponentially reduced.

  17. Memory effects in attenuation and amplification quantum processes

    CERN Document Server

    Lupo, Cosmo; Mancini, Stefano

    2010-01-01

    With increasing communication rates via quantum channels, memory effects become unavoidable whenever the use rate of the channel is comparable with the typical relaxation time of the channel environment. We then introduce a model of bosonic memory channel, describing correlated noise effects in quantum optical processes via attenuating or amplifying media. To study such a channel model we make use of a proper set of collective field variables, which allows us to unravel the memory effects, mapping the n-fold concatenation of the memory channel to a, unitarily equivalent, direct product of n single-mode bosonic channels. We hence estimate the channel capacities by relying on known results for the memoryless setting. Our findings show that the model is characterized by two different regimes, in which the cross-correlations induced by the noise among different channel uses are either exponentially enhanced or exponentially reduced.

  18. Effects of suppressing negative memories on intrusions and autobiographical memory specificity

    NARCIS (Netherlands)

    Geraerts, Elke; Hauer, Beatrijs J. A.; Wessel, Ineke

    2010-01-01

    This study examines whether avoidance of negative memories results in intrusions as well as reduced memory specificity. Healthy participants suppressed memories of either a negative or a neutral autobiographical event. Individuals who suppressed negative memories tended to demonstrate smaller increa

  19. Effects of suppressing negative memories on intrusions and autobiographical memory specificity

    NARCIS (Netherlands)

    Geraerts, Elke; Hauer, Beatrijs J. A.; Wessel, Ineke

    2010-01-01

    This study examines whether avoidance of negative memories results in intrusions as well as reduced memory specificity. Healthy participants suppressed memories of either a negative or a neutral autobiographical event. Individuals who suppressed negative memories tended to demonstrate smaller increa

  20. False memory = false memory: DRM errors are unrelated to the misinformation effect.

    Directory of Open Access Journals (Sweden)

    James Ost

    Full Text Available The DRM method has proved to be a popular and powerful, if controversial, way to study 'false memories'. One reason for the controversy is that the extent to which the DRM effect generalises to other kinds of memory error has been neither satisfactorily established nor subject to much empirical attention. In the present paper we contribute data to this ongoing debate. One hundred and twenty participants took part in a standard misinformation effect experiment, in which they watched some CCTV footage, were exposed to misleading post-event information about events depicted in the footage, and then completed free recall and recognition tests. Participants also completed a DRM test as an ostensibly unrelated filler task. Despite obtaining robust misinformation and DRM effects, there were no correlations between a broad range of misinformation and DRM effect measures (mean r  = -.01. This was not due to reliability issues with our measures or a lack of power. Thus DRM 'false memories' and misinformation effect 'false memories' do not appear to be equivalent.

  1. Low-level lead exposure effects on spatial reference memory and working memory in rats

    Institute of Scientific and Technical Information of China (English)

    Xinhua Yang; Ping Zhou; Yonghui Li

    2009-01-01

    BACKGROUND: Studies have demonstrated that lead exposure can result in cognitive dysfunction and behavior disorders. However, lead exposure impairments vary under different experimental conditions.OBJECTIVE: To detect changes in spatial learning and memory following low-level lead exposure in rats, in Morris water maze test under the same experimental condition used to analyze lead exposure effects on various memory types and learning processes.DESIGN AND SETTING: The experiment was conducted at the Animal Laboratory, Institute of Psychology, Chinese Academy of Science between February 2005 and March 2006. One-way analysis of variance (ANOVA) and behavioral observations were performed.MATERIALS: Sixteen male, healthy, adult, Sprague Dawley rats were randomized into normal control and lead exposure groups (n = 8).METHODS: Rats in the normal control group were fed distilled water, and those in the lead exposure group were fed 250 mL of 0.05% lead acetate once per day. At day 28, all rats performed the Morris water maze test, consisting of four phases: space navigation, probe test, working memory test, and visual cue test.MAIN OUTCOME MEASURES: Place navigation in the Morris water maze was used to evaluate spatial learning and memory, probe trials for spatial reference memory, working memory test for spatial working memory, and visual cue test for non-spatial cognitive function. Perkin-Elmer Model 300 Atomic Absorption Spectrometer was utilized to determine blood lead levels in rats.RESULTS: (1) In the working memory test, the time to reach the platform remained unchanged between the control and lead exposure groups (F(1,1) = 0.007, P = 0.935). A visible decrease in escape latencies was observed in each group (P = 0.028). However, there was no significant difference between the two groups (F(1,1) = 1.869, P = 0.193). The working memory probe test demonstrated no change between the two groups in the time spent in the target quadrant during the working memory probe test

  2. DSC study on temperature memory effect of NiTi shape memory alloy

    Institute of Scientific and Technical Information of China (English)

    N. LIU; W. M. HUANG

    2006-01-01

    A systematic study on the temperature memory effect (TME) in a polycrystalline NiTi shape memory alloy was presented. The investigation was carried out through a series of differential scanning calorimeter (DSC) tests. Two types of tests were conducted,namely single-step test and multi-step test. The influence of the step temperature on the peak/trough temperatures in the subsequent heating process and the associated energy absorption/release in the phase transformations was investigated. Using a simple theoretical model,the exact mechanism behind TME was studied.

  3. Electric Crosstalk Effect in Valence Change Resistive Random Access Memory

    Science.gov (United States)

    Sun, Jing; Wang, Hong; Wu, Shiwei; Song, Fang; Wang, Zhan; Gao, Haixia; Ma, Xiaohua

    2017-08-01

    Electric crosstalk phenomenon in valence change resistive switching memory (VCM) is systematically investigated. When a voltage is applied on the VCM device, an electric field is formed in the isolated region between the devices, which causes the oxygen vacancies in conductive filaments (CFs) to drift apart, leading to a consequent resistance degradation of the neighboring devices. The effects of distance between memory cells, electrodes widths and physical dimensions of CFs on the memory performance are investigated in this work. Furthermore, the strategies to mitigate electric crosstalk effects are developed. According to the simulation results, the crosstalk phenomenon can become more severe as the distance between memory cells or the electrode width decreases. In order to optimize the device performance, it is helpful to control the location of the break points of CFs in the device close to the top electrode. Alternatively, taking the integration density into account, switching materials with a small field accelerated parameter can also contribute to obtaining a stable performance.

  4. Long-term memory, sleep, and the spacing effect.

    Science.gov (United States)

    Bell, Matthew C; Kawadri, Nader; Simone, Patricia M; Wiseheart, Melody

    2014-01-01

    Many studies have shown that memory is enhanced when study sessions are spaced apart rather than massed. This spacing effect has been shown to have a lasting benefit to long-term memory when the study phase session follows the encoding session by 24 hours. Using a spacing paradigm we examined the impact of sleep and spacing gaps on long-term declarative memory for Swahili-English word pairs by including four spacing delay gaps (massed, 12 hours same-day, 12 hours overnight, and 24 hours). Results showed that a 12-hour spacing gap that includes sleep promotes long-term memory retention similar to the 24-hour gap. The findings support the importance of sleep to the long-term benefit of the spacing effect.

  5. Bidirectional Effects of Cannabidiol on Contextual Fear Memory Extinction

    Science.gov (United States)

    Song, Chenchen; Stevenson, Carl W.; Guimaraes, Francisco S.; Lee, Jonathan L. C.

    2016-01-01

    Cannabidiol (CBD) has been established to have both acute and long-lasting effects to reduce fear memory expression. The long-lasting impact might be mediated by an enhancement of memory extinction or an impairment of memory reconsolidation. Here, we directly compared the effects of i.p. injections of cannabidiol (10 mg/kg) with those of the NMDA receptor antagonist MK-801 (0.1 mg/kg) and partial agonist D-cycloserine (DCS; 15 mg/kg) in order to determine the mnemonic basis of long-term fear reduction. We showed that under conditions of strong fear conditioning, CBD reduced contextual fear memory expression both acutely during the extinction session as well as later at a fear retention test. The latter test reduction was replicated by DCS, but MK-801 instead elevated test freezing. In contrast, when initial conditioning was weaker, CBD and MK-801 had similar effects to increase freezing at the fear retention test relative to vehicle controls, whereas DCS had no observable impact. This pattern of results is consistent with CBD enhancing contextual fear memory extinction when the initial conditioning is strong, but impairing extinction when conditioning is weak. This bidirectional effect of CBD may be related to stress levels induced by conditioning and evoked at retrieval during extinction, rather than the strength of the memory per se. PMID:28018227

  6. Bidirectional effects of cannabidiol on contextual fear memory extinction

    Directory of Open Access Journals (Sweden)

    Chenchen Song

    2016-12-01

    Full Text Available Cannabidiol (CBD has been established to have both acute and long-lasting effects to reduce fear memory expression. The long-lasting impact might be mediated by an enhancement of memory extinction or an impairment of memory reconsolidation. Here, we directly compared the effects of i.p. injections of cannabidiol (10 mg/kg with those of the NMDA receptor antagonist MK-801 (0.1 mg/kg and partial agonist D-cycloserine (DCS; 15 mg/kg in order to determine the mnemonic basis of long-term fear reduction. We showed that under conditions of strong fear conditioning, CBD reduced contextual fear memory expression both acutely during the extinction session as well as later at a fear retention test. The latter test reduction was replicated by DCS, but MK-801 instead elevated test freezing. In contrast, when initial conditioning was weaker, CBD and MK-801 had similar effects to increase freezing at the fear retention test relative to vehicle controls, whereas DCS had no observable impact. This pattern of results is consistent with CBD enhancing contextual fear memory extinction when the initial conditioning is strong, but impairing extinction when conditioning is weak. This bidirectional effect of CBD may be related to stress levels induced by conditioning and evoked at retrieval during extinction, rather than the strength of the memory per se.

  7. Arousal Cues Arousal-Related Material in Memory: Implications for Understanding Effects of Mood on Memory.

    Science.gov (United States)

    Clark, Margaret S.; And Others

    1983-01-01

    Discusses research showing that material people learn when in a high arousal state and material they learn when in a normal arousal state is subsequently best recalled when they are in a similar arousal state. Speculates that this effect may partially underlie mood cuing, mood-related material from memory. (EKN)

  8. Neural protein synthesis during aging: effects on plasticity and memory

    Directory of Open Access Journals (Sweden)

    Lesley A Schimanski

    2010-08-01

    Full Text Available During aging, many experience a decline in cognitive function that includes memory loss. The encoding of long-term memories depends on new protein synthesis, and this is also reduced during aging. Thus, it is possible that changes in the regulation of protein synthesis contribute to the memory impairments observed in older animals. Several lines of evidence support this hypothesis. For instance, protein synthesis is required for a longer period following learning to establish long-term memory in aged rodents. Also, under some conditions, synaptic activity or pharmacological activation can induce de novo protein synthesis and lasting changes in synaptic transmission in aged, but not young, rodents; the opposite results can be observed in other conditions. These changes in plasticity likely play a role in manifesting the altered place field properties observed in awake and behaving aged rats. Thus, the collective evidence suggests a link between memory loss and the regulation of protein synthesis in senescence. In fact, pharmaceuticals that target the signaling pathways required for induction of protein synthesis have been shown to improve memory, synaptic plasticity, and place cell properties in aged animals. We suggest that a better understanding of the mechanisms that lead to different protein expression patterns in the neural circuits that change as a function of age will enable the development of more effective therapeutic treatments for memory loss.

  9. The sky pattern of the linearized gravitational memory effect

    Science.gov (United States)

    Mädler, Thomas; Winicour, Jeffrey

    2016-09-01

    The gravitational memory effect leads to a net displacement in the relative positions of test particles. This memory is related to the change in the strain of the gravitational radiation field between infinite past and infinite future retarded times. There are three known sources of the memory effect: (i) the loss of energy to future null infinity by massless fields or particles, (ii) the ejection of massive particles to infinity from a bound system and (iii) homogeneous, source-free gravitational waves. In the context of linearized theory, we show that asymptotic conditions controlling these known sources of the gravitational memory effect rule out any other possible sources with physically reasonable stress-energy tensors. Except for the source-free gravitational waves, the two other known sources produce gravitational memory with E-mode radiation strain, characterized by a certain curl-free sky pattern of their polarization. Thus our results show that the only known source of B-mode gravitational memory is of primordial origin, corresponding in the linearized theory to a homogeneous wave entering from past null infinity.

  10. The sky pattern of the linearized gravitational memory effect

    CERN Document Server

    Mädler, Thomas

    2016-01-01

    The gravitational memory effect leads to a net displacement in the relative positions of test particles. This memory is related to the change in the strain of the gravitational radiation field between infinite past and infinite future retarded times. There are three known sources of the memory effect: (i) the loss of energy to future null infinity by massless fields or particles, (ii) the ejection of massive particles to infinity from a bound system and (iii) homogeneous, source-free gravitational waves. In the context of linearized theory, we show that asymptotic conditions controlling these known sources of the gravitational memory effect rule out any other possible sources with physically reasonable stress-energy tensors. Except for the source-free gravitational waves, the two other known sources produce gravitational memory with E-mode radiation strain, characterized by a certain curl-free sky pattern of their polarization. Thus our results show that the only known source of B-mode gravitational memory is...

  11. The emotional carryover effect in memory for words.

    Science.gov (United States)

    Schmidt, Stephen R; Schmidt, Constance R

    2016-08-01

    Emotional material rarely occurs in isolation; rather it is experienced in the spatial and temporal proximity of less emotional items. Some previous researchers have found that emotional stimuli impair memory for surrounding information, whereas others have reported evidence for memory facilitation. Researchers have not determined which types of emotional items or memory tests produce effects that carry over to surrounding items. Six experiments are reported that measured carryover from emotional words varying in arousal to temporally adjacent neutral words. Taboo, non-taboo emotional, and neutral words were compared using different stimulus onset asynchronies (SOAs), recognition and recall tests, and intentional and incidental memory instructions. Strong emotional memory effects were obtained in all six experiments. However, emotional items influenced memory for temporally adjacent words under limited conditions. Words following taboo words were more poorly remembered than words following neutral words when relatively short SOAs were employed. Words preceding taboo words were affected only when recall tests and relatively short retention intervals were used. These results suggest that increased attention to the emotional items sometimes produces emotional carryover effects; however, retrieval processes also contribute to retrograde amnesia and may extend the conditions under which anterograde amnesia is observed.

  12. Memory boosting effect of Citrus limon, Pomegranate and their combinations.

    Science.gov (United States)

    Riaz, Azra; Khan, Rafeeq Alam; Algahtani, Hussein A

    2014-11-01

    Memory is greatly influenced by factors like food, stress and quality of sleep, hence present study was designed to evaluate the effect of Citrus limon and Pomegranate juices on memory of mice using Harvard Panlab Passive Avoidance response apparatus controlled through LE2708 Programmer. Passive avoidance is fear-motivated tests used to assess short or long-term memory of small animals, which measures latency to enter into the black compartment. Animals at MCLD showed highly significant and significant increase in latency to enter into the black compartment after 3 and 24 hours respectively than control, animals at HCLD showed significant increase in latency only after 3hours. Animals both at low and moderate doses of pomegranate showed significant increase in test latency after 3 hours, while animals at high dose showed highly significant and significant increase in latency after 3 and 24 hours respectively. There was highly significant and significant increase in latency in animals at CPJ-1 combination after 3 and 24 hours respectively; however animals received CPJ-2 combination showed significant increase in latency only after 3 hours as compare to control. These results suggest that Citrus limon and Pomegranate has phytochemicals and essential nutrients which boost memory, particularly short term memory. Hence it may be concluded that flavonoids in these juices may be responsible for memory enhancing effects and a synergistic effect is observed by CPJ-1 and CPJ-2 combinations.

  13. Control of crack pattern using memory effect of paste

    Energy Technology Data Exchange (ETDEWEB)

    Nakahara, Akio; Shinohara, Yuu; Matsuo, Yousuke, E-mail: nakahara@phys.ge.cst.nihon-u.ac.jp [Laboratory of Physics, College of Science and Technology, Nihon University, Funabashi 274-8501 (Japan)

    2011-09-15

    A densely packed colloidal suspension, called as a paste, remembers the direction of external mechanical fields, such as flow and vibration. When the pastes are dried, memories in pastes are visualized as macroscopically anisotropic crack patterns, such as lamellar, radial, ring and spiral. Here, we experimentally investigate how pastes remember such experiences by using paste with different size distribution of colloidal particles. We find that a paste with smaller particles have a better memory, in the sense it remembers external mechanical fields at smaller solid volume fraction, which implies that interparticle forces between colloidal particles play an important role in memory effects, causing a quantitative change in the phase diagram for the same material. This result supports the hypothesis that memories in pastes are maintained as microscopically anisotropic network structure of colloidal particles, connected via interparticle forces between colloidal particles, such as van der Waals interaction.

  14. Marijuana effects on long-term memory assessment and retrieval.

    Science.gov (United States)

    Darley, C F; Tinklenberg, J R; Roth, W T; Vernon, S; Kopell, B S

    1977-05-01

    The ability of 16 college-educated male subjects to recall from long-term memory a series of common facts was tested during intoxication with marijuana extract calibrated to 0.3 mg/kg delta-9-tetrahydrocannabinol and during placebo conditions. The subjects' ability to assess their memory capabilities was then determined by measuring how certain they were about the accuracy of their recall performance and by having them predict their performance on a subsequent recognition test involving the same recall items. Marijuana had no effect on recall or recognition performance. These results do not support the view that marijuana provides access to facts in long-term storage which are inaccessible during non-intoxication. During both marijuana and placebo conditions, subjects could accurately predict their recognition memory performance. Hence, marijuana did not alter the subjects' ability to accurately assess what information resides in long-term memory even though they did not have complete access to that information.

  15. Aging and emotional memory: cognitive mechanisms underlying the positivity effect.

    Science.gov (United States)

    Spaniol, Julia; Voss, Andreas; Grady, Cheryl L

    2008-12-01

    Younger adults tend to remember negative information better than positive or neutral information (negativity bias). The negativity bias is reduced in aging, with older adults occasionally exhibiting superior memory for positive, as opposed to negative or neutral, information (positivity bias). Two experiments with younger (N=24 in Experiment 1, N=25 in Experiment 2; age range: 18-35 years) and older adults (N=24 in both experiments; age range: 60-85 years) investigated the cognitive mechanisms responsible for age-related differences in recognition memory for emotional information. Results from diffusion model analyses (R. Ratcliff, 1978) indicated that the effects of valence on response bias were similar in both age groups but that Age x Valence interactions emerged in memory retrieval. Specifically, older adults experienced greater overall familiarity for positive items than younger adults. We interpret this finding in terms of an age-related increase in the accessibility of positive information in long-term memory.

  16. The effect of Twitter exposure on false memory formation.

    Science.gov (United States)

    Fenn, Kimberly M; Griffin, Nicholas R; Uitvlugt, Mitchell G; Ravizza, Susan M

    2014-12-01

    Social media sites such as Facebook and Twitter have increased drastically in popularity. However, information on these sites is not verified and may contain inaccuracies. It is well-established that false information encountered after an event can lead to memory distortion. Therefore, social media may be particularly harmful for autobiographical memory. Here, we tested the effect of Twitter on false memory. We presented participants with a series of images that depicted a story and then presented false information about the images in a scrolling feed that bore either a low or high resemblance to a Twitter feed. Confidence for correct information was similar across the groups, but confidence for suggested information was significantly lower when false information was presented in a Twitter format. We propose that individuals take into account the medium of the message when integrating information into memory.

  17. Thermal Arrest Memory Effect in Ni-Mn-Ga Alloys

    Directory of Open Access Journals (Sweden)

    A. Rudajevova

    2008-01-01

    Full Text Available Dilatation characteristics were measured to investigate the thermal arrest memory effect in Ni53.6Mn27.1Ga19.3 and Ni54.2Mn29.4Ga16.4 alloys. Interruption of the martensite-austenite phase transformation is connected with the reduction of the sample length after thermal cycle. If a total phase transformation took place in the complete thermal cycle following the interruption, then the sample length would return to its original length. Analysis of these results has shown that the thermal arrest memory effect is a consequence of a stress-focusing effect and shape memory effect. The stress-focusing effect occurs when the phase transformation propagates radially in a cylindrical sample from the surface, inward to the center. Evolution and release of the thermoelastic deformations in both alloys during heating and cooling are analyzed.

  18. Effects of magnetic field on the shape memory behavior of single and polycrystalline magnetic shape memory alloys

    Science.gov (United States)

    Turabi, Ali Sadi

    Shape memory alloys and polymers have been extensively researched recently because of their unique ability to recover large deformations. Shape memory polymers (SMPs) are able to recover large deformations compared to shape memory alloys (SMAs), although SMAs have higher strength and are able to generate more stress during recovery. This project focuses on procedure for fabrication and Finite Element Modeling (FEM) of a shape memory composite actuator. First, SMP was characterized to reveal its mechanical properties. Specifically, glass transition temperature, the effects of temperature and strain rate on compressive response and recovery properties of shape memory polymer were studied. Then, shape memory properties of a NiTi wire, including transformation temperatures and stress generation, were investigated. SMC actuator was fabricated by using epoxy based SMP and NiTi SMA wire. Experimental tests confirmed the reversible behavior of fabricated shape memory composites. (Abstract shortened by ProQuest.).

  19. Aging and the Effects of Exploratory Behavior on Spatial Memory.

    Science.gov (United States)

    Varner, Kaitlin M; Dopkins, Stephen; Philbeck, John W

    2016-03-01

    The present research examined the effect of encoding from multiple viewpoints on scene recall in a group of younger (18-22 years) and older (65-80 years) adults. Participants completed a visual search task, during which they were given the opportunity to examine a room using two sets of windows that partitioned the room differently. Their choice of window set was recorded, to determine whether an association between these choices and spatial memory performance existed. Subsequently, participants were tested for spatial memory of the domain in which the search task was completed. Relative to younger adults, older adults demonstrated an increased tendency to use a single set of windows as well as decreased spatial memory for the domain. Window-set usage was associated with spatial memory, such that older adults who relied more heavily on a single set of windows also had better performance on the spatial memory task. These findings suggest that, in older adults, moderation in exploratory behavior may have a positive effect on memory for the domain of exploration.

  20. Expert Knowledge-Based Automatic Sleep Stage Determination by Multi-Valued Decision Making Method

    Science.gov (United States)

    Wang, Bei; Sugi, Takenao; Kawana, Fusae; Wang, Xingyu; Nakamura, Masatoshi

    In this study, an expert knowledge-based automatic sleep stage determination system working on a multi-valued decision making method is developed. Visual inspection by a qualified clinician is adopted to obtain the expert knowledge database. The expert knowledge database consists of probability density functions of parameters for various sleep stages. Sleep stages are determined automatically according to the conditional probability. Totally, four subjects were participated. The automatic sleep stage determination results showed close agreements with the visual inspection on sleep stages of awake, REM (rapid eye movement), light sleep and deep sleep. The constructed expert knowledge database reflects the distributions of characteristic parameters which can be adaptive to variable sleep data in hospitals. The developed automatic determination technique based on expert knowledge of visual inspection can be an assistant tool enabling further inspection of sleep disorder cases for clinical practice.

  1. Common fixed points for some generalized multivalued nonexpansive mappings in uniformly convex metric spaces

    Directory of Open Access Journals (Sweden)

    Laowang Worawut

    2011-01-01

    Full Text Available Abstract Abkar and Eslamian (Nonlinear Anal. TMA, 74, 1835-1840, 2011 prove that if K is a nonempty bounded closed convex subset of a complete CAT(0 space X, t : K → K is a single-valued quasi-nonexpansive mapping and T : K → KC(K is a multivalued mapping satisfying conditions (E and (Cλ for some λ ∈ (0, 1 such that t and T commute weakly, then there exists a point z ∈ K such that z = t(z ∈ T(z. In this paper, we extend this result to the general setting of uniformly convex metric spaces. Nevertheless, condition (E of T can be weakened to the strongly demiclosedness of I - T.

  2. Noise-based logic: Binary, multi-valued, or fuzzy, with optional superposition of logic states

    CERN Document Server

    Kish, Laszlo B

    2008-01-01

    A new type of deterministic (non-probabilistic) computer logic system inspired by the stochasticity of brain signals is shown. The distinct values are represented by independent stochastic processes: independent voltage (or current) noises. The orthogonality of these processes provides a natural way to construct binary or multi-valued logic circuitry with arbitrary number N of logic values by using analog circuitry. Moreover, the logic values on a single wire can be made a (weighted) superposition of the N distinct logic values. Fuzzy logic is also naturally represented by a two-component superposition within the binary case (N=2). Error propagation and accumulation are suppressed. Other relevant advantages are reduced energy dissipation and leakage current problems, and robustness against circuit noise and background noises such as 1/f, Johnson, shot and crosstalk noise. Variability problems are also nonexistent because the logic value is an AC signal. A similar logic system can be built with orthogonal sinu...

  3. Visualization and processing of higher order descriptors for multi-valued data

    CERN Document Server

    Schultz, Thomas

    2015-01-01

    Modern imaging techniques and computational simulations yield complex multi-valued data that require higher-order mathematical descriptors. This book addresses topics of importance when dealing with such data, including frameworks for image processing, visualization, and statistical analysis of higher-order descriptors. It also provides examples of the successful use of higher-order descriptors in specific applications and a glimpse of the next generation of diffusion MRI. To do so, it combines contributions on new developments, current challenges in this area, and state-of-the-art surveys.   Compared to the increasing importance of higher-order descriptors in a range of applications, tools for analysis and processing are still relatively hard to come by. Even though application areas such as medical imaging, fluid dynamics, and structural mechanics are very different in nature they face many shared challenges. This book provides an interdisciplinary perspective on this topic with contributions from key rese...

  4. Delayed effects of cortisol enhance fear memory of trace conditioning

    NARCIS (Netherlands)

    Cornelisse, S.; Ast, V.A. van; Joëls, M.; Kindt, M.

    2014-01-01

    Corticosteroids induce rapid non-genomic effects followed by slower genomic effects that are thought to modulate cognitive function in opposite and complementary ways. It is presently unknown how these time-dependent effects of cortisol affect fear memory of delay and trace conditioning. This distin

  5. Reassessing the Basis of the Production Effect in Memory

    Science.gov (United States)

    Bodner, Glen E.; Taikh, Alexander

    2012-01-01

    The production effect refers to a memory advantage for items studied aloud over items studied silently. Ozubko and MacLeod (2010) used a list-discrimination task to support a distinctiveness account of the production effect over a strength account. We report new findings in this task--including negative production effects--that better fit with an…

  6. Delayed effects of cortisol enhance fear memory of trace conditioning

    NARCIS (Netherlands)

    Cornelisse, S.; Ast, V.A. van; Joëls, M.; Kindt, M.

    2014-01-01

    Corticosteroids induce rapid non-genomic effects followed by slower genomic effects that are thought to modulate cognitive function in opposite and complementary ways. It is presently unknown how these time-dependent effects of cortisol affect fear memory of delay and trace conditioning. This distin

  7. The Modality-Match Effect in Recognition Memory

    Science.gov (United States)

    Mulligan, Neil W.; Osborn, Katherine

    2009-01-01

    The modality-match effect in recognition refers to superior memory for words presented in the same modality at study and test. Prior research on this effect is ambiguous and inconsistent. The present study demonstrates that the modality-match effect is found when modality is rendered salient at either encoding or retrieval. Specifically, in…

  8. Improved Hall-Effect Sensors For Magnetic Memories

    Science.gov (United States)

    Wu, Jiin-Chuan; Stadler, Henry L.; Katti, Romney R.; Chen, Y. C.; Bhattacharya, Pallab K.

    1993-01-01

    High-electron-mobility sensor films deposited on superlattice buffer (strain) layers. Improved Hall-effect sensors offer combination of adequate response and high speed needed for use in micromagnet/Hall-effect random-access memories. Hall-effect material chosen for use in sensors is InAs.

  9. Sex-Related Differences in the Effects of Sleep Habits on Verbal and Visuospatial Working Memory

    OpenAIRE

    Seishu Nakagawa; Hikaru Takeuchi; Yasuyuki Taki; Rui Nouchi; Atsushi Sekiguchi; Yuka Kotozaki; Carlos Makoto Miyauchi; Kunio Iizuka; Ryoichi Yokoyama; Takamitsu Shinada; Yuki Yamamoto; Sugiko Hanawa; Tsuyoshi Araki; Keiko Kunitoki; Yuko Sassa

    2016-01-01

    Sleep facilitates memory consolidation. Consequently, poor sleep quality negatively affects memory performance, and working memory in particular. We investigated sleep habits related to sleep quality including sleep duration, daytime nap duration, nap frequency, and dream content recall frequency (DCRF). Declarative working memory can be subdivided into verbal working memory (VWM) and visuospatial working memory (VSWM). We hypothesized that sleep habits would have different effects on VWM and...

  10. Memory effect versus exchange bias for maghemite nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Nadeem, K., E-mail: kashif.nadeem@iiu.edu.pk [Materials Research Laboratory, Department of Physics, International Islamic University, Islamabad (Pakistan); Krenn, H. [Institute of Physics, Karl-Franzens University Graz, Universitätsplatz 5, A-8010 Graz (Austria); Szabó, D.V. [Karlsruhe Institute of Technology, Institute for Applied Materials, 76344 Eggenstein-Leopoldshafen (Germany)

    2015-11-01

    We studied the temperature dependence of memory and exchange bias effects and their dependence on each other in maghemite (γ-Fe{sub 2}O{sub 3}) nanoparticles by using magnetization studies. Memory effect in zero field cooled process in nanoparticles is a fingerprint of spin-glass behavior which can be due to i) surface disordered spins (surface spin-glass) and/or ii) randomly frozen and interacting nanoparticles core spins (super spin-glass). Temperature region (25–70 K) for measurements has been chosen just below the average blocking temperature (T{sub B}=75 K) of the nanoparticles. Memory effect (ME) shows a non-monotonous behavior with temperature. It shows a decreasing trend with decreasing temperature and nearly vanishes below 30 K. However it also decreased again near the blocking temperature of the nanoparticles e.g., 70 K. Exchange bias (EB) in these nanoparticles arises due to core/shell interface interactions. The EB increases sharply below 30 K due to increase in core/shell interactions, while ME starts vanishing below 30 K. We conclude that the core/shell interface interactions or EB have not enhanced the ME but may reduce it in these nanoparticles. - Highlights: • We studied the T-dependent memory and exchange bias (EB) effects in maghemite nanoparticles. • EB causes spin-canting at the core/shell interface which may reduces the memory effect (ME). • Interface interactions does not increase the ME in these nanoparticles.

  11. Adult eyewitness memory and compliance: effects of post-event misinformation on memory for a negative event.

    Science.gov (United States)

    Paz-Alonso, Pedro M; Goodman, Gail S; Ibabe, Izaskun

    2013-01-01

    This study investigated effects of misleading post-event information, delay, and centrality definition on eyewitness memory and suggestibility for a negative event (a vividly filmed murder). Either immediately or 2 weeks after viewing the film, 93 adults read a (misleading or control) narrative about the event and then completed a recognition memory test. Misinformation acceptance was operative, but strong evidence for memory malleability was lacking. Compliance predicted misinformation effects, especially on the delayed test. Although accuracy was generally higher for central than peripheral information, centrality criteria influenced the pattern of results. Self-report of greater distress was associated with better recognition accuracy. The results suggest that use of different centrality definitions may partly explain inconsistencies across studies of memory and suggestibility for central and peripheral information. Moreover, social factors appeared, at least in part, to influence misinformation effects for the highly negative event, especially as memory faded. Implications for eyewitness memory and suggestibility are discussed.

  12. Space and terrestrial radiation effects in flash memories

    Science.gov (United States)

    Bagatin, Marta; Gerardin, Simone; Paccagnella, Alessandro

    2017-03-01

    We present a comprehensive review of the effects of ionizing radiation on advanced flash memories. The effects of ionizing radiation as well as the mechanisms underlying the observed phenomena are thoroughly discussed on both floating gate cells and the complex control circuitry. The covered effects are relevant for all floating-gate based flash memories that require very high levels of reliability, from critical applications at the terrestrial level to radiation-harsh environments, such as space, nuclear power plants, and high-energy physics experiments.

  13. Memory for tonal pitches: a music-length effect hypothesis.

    Science.gov (United States)

    Akiva-Kabiri, Lilach; Vecchi, Tomaso; Granot, Roni; Basso, Demis; Schön, Daniele

    2009-07-01

    One of the most studied effects of verbal working memory (WM) is the influence of the length of the words that compose the list to be remembered. This work aims to investigate the nature of musical WM by replicating the word length effect in the musical domain. Length and rate of presentation were manipulated in a recognition task of tone sequences. Results showed significant effects for both factors (length and presentation rate) as well as their interaction, suggesting the existence of different strategies (e.g., chunking and rehearsal) for the immediate memory of musical information, depending upon the length of the sequences.

  14. Sleep and environmental context: interactive effects for memory.

    Science.gov (United States)

    Cairney, Scott A; Durrant, Simon J; Musgrove, Hazel; Lewis, Penelope A

    2011-09-01

    Sleep after learning is often beneficial for memory. Reinstating an environmental context that was present at learning during subsequent retrieval also leads to superior declarative memory performance. This study examined how post-learning sleep, relative to wakefulness, impacts upon context-dependent memory effects. Thirty-two participants encoded word lists in each of two rooms (contexts), which were different in terms of size, odour and background music. Immediately after learning and following a night of sleep or a day of wakefulness, memory for all previously studied words was tested using a category-cued recall task in room one or two alone. Accordingly, a comparison could be made between words retrieved in an environmental context which was the same as, or different to, that of the learning phase. Memory performance was assessed by the difference between the number of words remembered at immediate and delayed retrieval. A 2 × 2 × 2 mixed ANOVA revealed an interaction between retrieval context (same/different to learning) and retention interval (sleep/wakefulness), which was driven by superior memory after sleep than after wake when learning and retrieval took place in different environmental contexts. Our findings suggest a sleep-related reduction in the extent to which context impacts upon retrieval. As such, these data provide initial support for the possibility that sleep dependent processes may promote a decontextualisation of recently formed declarative representations.

  15. The Electromagnetic Christodoulou Memory Effect in Neutron Star Binary Mergers

    CERN Document Server

    Bieri, Lydia; Yau, Shing-Tung

    2011-01-01

    Gravitational waves are predicted by the general theory of relativity. In [6] D. Christodoulou showed that gravitational waves have a nonlinear memory. We proved in [3] that the electromagnetic field contributes at highest order to the nonlinear memory effect of gravitational waves. In the present paper, we study this electromagnetic Christodoulou memory effect and compute it for binary neutron star mergers. These are typical sources of gravitational radiation. During these processes, not only mass and momenta are radiated away in form of gravitational waves, but also very strong magnetic fields are produced and radiated away. Thus the observed effect on test masses of a laser interferometer gravitational wave detector will be enlarged by the contribution of the electromagnetic field. Therefore, the present results are important for the planned experiments. Looking at the null asymptotics of spacetimes, which are solutions of the Einstein-Maxwell (EM) equations, we derived in [3] the electromagnetic Christodo...

  16. Memory for contextual details: effects of emotion and aging.

    Science.gov (United States)

    Kensinger, Elizabeth A; Piguet, Olivier; Krendl, Anne C; Corkin, Suzanne

    2005-06-01

    When individuals are confronted with a complex visual scene that includes some emotional element, memory for the emotional component often is enhanced, whereas memory for peripheral (nonemotional) details is reduced. The present study examined the effects of age and encoding instructions on this effect. With incidental encoding instructions, young and older adults showed this pattern of results, indicating that both groups focused attention on the emotional aspects of the scene. With intentional encoding instructions, young adults no longer showed the effect: They were just as likely to remember peripheral details of negative images as of neutral images. The older adults, in contrast, did not overcome the attentional bias: They continued to show reduced memory for the peripheral elements of the emotional compared with the neutral scenes, even with the intentional encoding instructions.

  17. Effect of partial hepatectomy on the memory ability in rats

    Institute of Scientific and Technical Information of China (English)

    Zhouquan Wu; Yanjie Wan; Yanxia Wang; Yinming Zeng

    2007-01-01

    BACKGROUND: Patients suffer from changes of cognitive function postoperatively, which has attracted extensive attentions in clinic. It is still to be investigated whether operation damages both antegrade memory and retrograde memory, or either of them.OBJECTIVE: To observe the effects of operation on the anterograde and retrograde memory with Y maze test.DESIGN: A randomly controlled animal trial.SETTING: Department of Anesthesiology, Pudong New Area Gongli Hospital of Shanghai City. MATERIALS: Sixty-three male healthy Sprague-Dawley (SD) rats of clean degree, weighing 200 - 250 g, 10 weeks old, were provided by the animal center of Chinese Academy of Sciences. The rats were tested by antegrade and retrograde respectively. The rats were randomly divided into normal control group (n =7), anesthesia group (n =14), sham-operated group (n =14); partial hepatectomy group (n =14), short-term retrograde memory group (n =7) and long-term retrograde memory group (n =7). According to the time of Y maze training started, rats in the anesthesia group, sham-operated group and partial hepatectomy group were observed at 1 and 7 days after anesthesia.METHODS: The experiments were carried out in the central laboratory of Pudong New Area Gongli Hospital of Shanghai City from February to June in 2006.①Test for antegrade memory: Rats in the normal control group were only treated with intraperitoneal injection of saline without aesthesia and operation; Those in the anesthesia group were anesthetized with intraperitoneal injection of 10 g/L pentobarbital sodium (40 mg/kg); Those in the sham-operated group were anesthetized, then intraperitoneal exploration was performed without hepatectomy; Those in the partial hepatectomy group were anesthetized, then fixed in a supine position after righting reflex disappeared, and an incision of 1.5 - 2.0 cm was made along the midline of xiphoid lower abdomen, then left lateral lobe of liver (about 1/3 of total liver) was freed, and ligated at

  18. Memory function after stress : the effects of acute stress and cortisol on memory and the inhibition of emotional distraction

    NARCIS (Netherlands)

    Oei, Nicole Yü Lan

    2010-01-01

    The present thesis contains five experimental studies into the effects of stress on memory I healthy males. Hydrocortisone (and propranolol) administration or the induction of social stress are used to heighten cortisol levels, and consequently to study its effects on working memory performance and

  19. Memory function after stress : the effects of acute stress and cortisol on memory and the inhibition of emotional distraction

    NARCIS (Netherlands)

    Oei, Nicole Yü Lan

    2010-01-01

    The present thesis contains five experimental studies into the effects of stress on memory I healthy males. Hydrocortisone (and propranolol) administration or the induction of social stress are used to heighten cortisol levels, and consequently to study its effects on working memory performance and

  20. The Self-Reference Effect on Memory in Early Childhood

    Science.gov (United States)

    Cunningham, Sheila J.; Brebner, Joanne L.; Quinn, Francis; Turk, David J.

    2014-01-01

    The self-reference effect in memory is the advantage for information encoded about self, relative to other people. The early development of this effect was explored here using a concrete encoding paradigm. Trials comprised presentation of a self- or other-image paired with a concrete object. In Study 1, 4- to 6-year-old children (N = 53) were…

  1. Is Working Memory Training Effective? A Meta-Analytic Review

    Science.gov (United States)

    Melby-Lervag, Monica; Hulme, Charles

    2013-01-01

    It has been suggested that working memory training programs are effective both as treatments for attention-deficit/hyperactivity disorder (ADHD) and other cognitive disorders in children and as a tool to improve cognitive ability and scholastic attainment in typically developing children and adults. However, effects across studies appear to be…

  2. The Effects of Caffeine on Memory for Word Lists.

    Science.gov (United States)

    Erikson, George; And Others

    Research has suggested that behavioral differences may account for the effects of caffeine on information processing. To investigate the effects of caffeine on memory for supraspan word lists, 107 college students (47 males, 60 females), divided into 12 groups by high and low impulsivity scores on the Eysenck Personality Inventory, participated in…

  3. Effect of two prednisone exposures on mood and declarative memory.

    Science.gov (United States)

    Brown, E Sherwood; Beard, Laura; Frol, Alan B; Rush, A John

    2006-07-01

    Corticosteroids are essential for life and an integral part of the stress response. However, in excess, corticosteroids can be associated with a variety of effects on the brain including hippocampal atrophy and even neuronal death, mood changes, and declarative memory impairment. The magnitude of mood change in patients receiving prednisone is reportedly associated with previous lifetime corticosteroid exposure, consistent with a sensitization or kindling process whereby greater effects are observed with repeated exposure. To our knowledge, the effect of multiple corticosteroid exposures on mood and memory has not been previously examined prospectively in animals or humans. In this study, 30 human volunteers, with no history of systemic prescription corticosteroid therapy, were given (in random order using a crossover design) two 3-day exposures of prednisone (60 mg/day) and one of identical placebo, with 11-day washouts between each medication exposure. Before and after each 3-day prednisone/placebo exposure, declarative memory was assessed using different versions of the Rey Auditory Verbal Learning Test (RAVLT) to minimize practice or learning effects, while mood was assessed with the 21-item Hamilton Rating Scale for Depression, Young Mania Rating Scale and Internal State Scale. No significant mood changes were found. However, a significant decrease in aspects of RAVLT performance was observed after the first prednisone exposure consistent with a decline in declarative memory performance. The decline in RAVLT performance was significantly smaller after the second prednisone exposure as compared to the initial prednisone exposure. Thus, a second prednisone exposure was associated with an attenuated prednisone-effect on declarative memory. These data suggest tolerance or habituation, rather than sensitization, to prednisone effects on declarative memory during a second exposure. Implications and possible explanations for the findings are discussed.

  4. Temporal correlations and structural memory effects in break junction measurements

    DEFF Research Database (Denmark)

    Magyarkuti, A.; Lauritzen, Kasper Primdal; Balogh, Zoltan Imre

    2017-01-01

    that correlations between the opening and subsequent closing traces may indicate structural memory effects in atomic-sized metallic and molecular junctions. Applying these methods on measured and simulated gold metallic contacts as a test system, we show that the surface diffusion induced flattening of the broken......-molecule junctions, we demonstrate pronounced contact memory effects and recovery of the molecule for junctions breaking before atomic chains are formed. However, if chains are pulled the random relaxation of the chain and molecule after rupture prevents opening-closing correlations....

  5. Nonlocal memory effects in the dynamics of open quantum systems

    CERN Document Server

    Laine, Elsi-Mari; Piilo, Jyrki; Li, Chuan-Feng; Guo, Guang-Can

    2011-01-01

    We study a model of two entangled photons interacting locally with two dephasing environments. It is shown that initial correlations between the local environments can generate a nonlocal quantum process from a local interaction Hamiltonian. While the global dynamics of the two-photon polarization state exhibits strong memory effects, the induced local dynamics of either of the two photons is found to be Markovian. A direct connection between the degree of memory effects and the amount of correlations in the initial environmental state is derived. The results demonstrate that, contrary to conventional wisdom, enlarging an open system can change the dynamics from Markovian to non-Markovian.

  6. Two-way shape memory effect and its stability in Ti-Ni-Hf high temperature shape memory alloy

    Institute of Scientific and Technical Information of China (English)

    MENG Xiang-long; WU Ye; CAI Wei; ZHAO Lian-cheng

    2005-01-01

    The two-way shape memory effect (TWSME) in a Ti36 Ni49 Hf15 high temperature shape memory alloy (SMA) was systematically studied by bending tests. In the TiNiHf alloy, the martensite deformation is an effective method to get two-way shape memory effect even with a small deformation strain. The results indicate that the internal stress field formed by the bending deformation is in the direction of the preferentially oriented martensite variants formed during the bending deformation. Upon cooling the preferentially oriented martensite variants form under such an oriented stress field, which should be responsible for the generation of the two-way shape memory effect.Proper training process benefits the formation of the oriented stress field, resulting in the improvement of the twoway shape memory effect. A maximum TWSME of 0.88 % is obtained in the present alloy.

  7. Beneficial effects of semantic memory support on older adults' episodic memory: Differential patterns of support of item and associative information.

    Science.gov (United States)

    Mohanty, Praggyan Pam; Naveh-Benjamin, Moshe; Ratneshwar, Srinivasan

    2016-02-01

    The effects of two types of semantic memory support-meaningfulness of an item and relatedness between items-in mitigating age-related deficits in item and associative, memory are examined in a marketing context. In Experiment 1, participants studied less (vs. more) meaningful brand logo graphics (pictures) paired with meaningful brand names (words) and later were assessed by item (old/new) and associative (intact/recombined) memory recognition tests. Results showed that meaningfulness of items eliminated age deficits in item memory, while equivalently boosting associative memory for older and younger adults. Experiment 2, in which related and unrelated brand logo graphics and brand name pairs served as stimuli, revealed that relatedness between items eliminated age deficits in associative memory, while improving to the same degree item memory in older and younger adults. Experiment 2 also provided evidence for a probable boundary condition that could reconcile seemingly contradictory extant results. Overall, these experiments provided evidence that although the two types of semantic memory support can improve both item and associative memory in older and younger adults, older adults' memory deficits can be eliminated when the type of support provided is compatible with the type of information required to perform well on the test. (c) 2016 APA, all rights reserved).

  8. Nonvolatile memory effect of tungsten nanocrystals under oxygen plasma treatments

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Shih-Cheng, E-mail: scchen0213@gmail.co [Department of Electrical Engineering and Institute of Electronic Engineering, National Tsing Hua University, Taiwan (China); Chang, Ting-Chang [Department of Physics and Institute of Electro-Optical Engineering, and Center for Nanoscience and Nanotechnology, National Sun Yat-Sen University, Taiwan (China); Chen, Wei-Ren [Institute of Electronics, National Chiao Tung University, Taiwan, Hsinchu, Taiwan 300 (China); Lo, Yuan-Chun; Wu, Kai-Ting [Institute of Photonics Technologies, National Tsing Hua University, Taiwan (China); Sze, S.M. [Institute of Electronics, National Chiao Tung University, Taiwan, Hsinchu, Taiwan 300 (China); Chen, Jason; Liao, I.H. [ProMOS Technologies, No. 19 Li Hsin Rd., Science-Based Industrial Park, Hsinchu, Taiwan 300 (China); Yeh, Fon-Shan [Department of Electrical Engineering and Institute of Electronic Engineering, National Tsing Hua University, Taiwan (China)

    2010-10-01

    In this work, an oxygen plasma treatment was used to improve the memory effect of nonvolatile W nanocrystal memory, including memory window, retention and endurance. To investigate the role of the oxygen plasma treatment in charge storage characteristics, the X-ray photon-emission spectra (XPS) were performed to analyze the variation of chemical composition for W nanocrystal embedded oxide both with and without the oxygen plasma treatment. In addition, the transmission electron microscopy (TEM) analyses were also used to identify the microstructure in the thin film and the size and density of W nanocrystals. The device with the oxygen plasma treatment shows a significant improvement of charge storage effect, because the oxygen plasma treatment enhanced the quality of silicon oxide surrounding the W nanocrystals. Therefore, the data retention and endurance characteristics were also improved by the passivation.

  9. Blocked Shape Memory Effect in Negative Poisson's Ratio Polymer Metamaterials.

    Science.gov (United States)

    Boba, Katarzyna; Bianchi, Matteo; McCombe, Greg; Gatt, Ruben; Griffin, Anselm C; Richardson, Robert M; Scarpa, Fabrizio; Hamerton, Ian; Grima, Joseph N

    2016-08-10

    We describe a new class of negative Poisson's ratio (NPR) open cell PU-PE foams produced by blocking the shape memory effect in the polymer. Contrary to classical NPR open cell thermoset and thermoplastic foams that return to their auxetic phase after reheating (and therefore limit their use in technological applications), this new class of cellular solids has a permanent negative Poisson's ratio behavior, generated through multiple shape memory (mSM) treatments that lead to a fixity of the topology of the cell foam. The mSM-NPR foams have Poisson's ratio values similar to the auxetic foams prior their return to the conventional phase, but compressive stress-strain curves similar to the ones of conventional foams. The results show that by manipulating the shape memory effect in polymer microstructures it is possible to obtain new classes of materials with unusual deformation mechanisms.

  10. The effect of estrogen synthesis inhibition on hippocampal memory.

    Science.gov (United States)

    Bayer, Janine; Rune, Gabriele; Schultz, Heidrun; Tobia, Michael J; Mebes, Imke; Katzler, Olaf; Sommer, Tobias

    2015-06-01

    17-Beta-estradiol (E2) facilitates long term-potentiation (LTP) and increases spine synapse density in hippocampal neurons of ovariectomized rodents. Consistent with these beneficial effects on the cellular level, E2 improves hippocampus-dependent memory. A prominent approach to study E2 effects in rodents is the inhibition of its synthesis by letrozole, which reduces LTPs and spine synapse density. In the current longitudinal functional magnetic resonance imaging (fMRI) study, we translated this approach to humans and compared the impact of E2 synthesis inhibition on memory performance and hippocampal activity in post-menopausal women taking letrozole (n = 21) to controls (n = 24). In particular, we employed various behavioral memory paradigms that allow the disentanglement of hippocampus-dependent and -independent memory. Consistent with the literature on rodents, E2 synthesis inhibition specifically impaired hippocampus-dependent memory, however, this did not apply to the same degree to all of the employed paradigms. On the neuronal level, E2 depletion tended to decrease hippocampal activity during encoding, whereas it increased activity in the anterior cingulate and the dorsolateral prefrontal cortex. We thus infer that the inhibition of E2 synthesis specifically impairs hippocampal functioning in humans, whereas the increased prefrontal activity presumably reflects a compensatory mechanism, which is already known from studies on cognitive aging and Alzheimer's disease.

  11. Working memory in multilingual children: is there a bilingual effect?

    Science.gov (United States)

    Engel de Abreu, Pascale M J

    2011-07-01

    This research investigates whether early childhood bilingualism affects working memory performance in 6- to 8-year-olds, followed over a longitudinal period of 3 years. The study tests the hypothesis that bilinguals might exhibit more efficient working memory abilities than monolinguals, potentially via the opportunity a bilingual environment provides to train cognitive control by combating interference and intrusions from the non-target language. A total of 44 bilingual and monolingual children, matched on age, sex, and socioeconomic status, completed assessments of working memory (simple span and complex span tasks), fluid intelligence, and language (vocabulary and syntax). The data showed that the monolinguals performed significantly better on the language measures across the years, whereas no language group effect emerged on the working memory and fluid intelligence tasks after verbal abilities were considered. The study suggests that the need to manage several language systems in the bilingual mind has an impact on children's language skills while having little effects on the development of working memory.

  12. Visuomotor memory in elderly: effect of a physical exercise program

    Directory of Open Access Journals (Sweden)

    João Silva

    2014-12-01

    Full Text Available Memory, namely visuomotor memory, is one of the most essential cognitive functions in elder’s life. Among others, regular exercise seems to be an important factor in counteracting age-related-cognitive skills changes and thus prevent memory loss. However, in spite of the importance of visuomotor memory, the results of the scarce studies concerning the influence of exercise on this capacity are contradictory. The aim of this study was to investigate the effect of physical exercise (PE in visuomotor memory (VMM of elderly adults in function of gender and age. VMM (time spent in performing the test and errors during the execution of 74 subjects aged 60-90 years, being 36 practitioners of PE (P - mean age of 70.22 ± 0.90 years and 38 non-practitioners (NP - mean age of 68.26 ± 1.12 years were assessed by VMM Test. The results showed that: a P presented a better performance in the time of performing the test and in the number of errors committed compared to NP; b Gender and age did not influence the VMM performance. Data suggest that PE seems to have positive effect in the VMM, independently of gender and age.

  13. Task-selective memory effects for successfully implemented encoding strategies.

    Directory of Open Access Journals (Sweden)

    Eric D Leshikar

    Full Text Available Previous behavioral evidence suggests that instructed strategy use benefits associative memory formation in paired associate tasks. Two such effective encoding strategies--visual imagery and sentence generation--facilitate memory through the production of different types of mediators (e.g., mental images and sentences. Neuroimaging evidence suggests that regions of the brain support memory reflecting the mental operations engaged at the time of study. That work, however, has not taken into account self-reported encoding task success (i.e., whether participants successfully generated a mediator. It is unknown, therefore, whether task-selective memory effects specific to each strategy might be found when encoding strategies are successfully implemented. In this experiment, participants studied pairs of abstract nouns under either visual imagery or sentence generation encoding instructions. At the time of study, participants reported their success at generating a mediator. Outside of the scanner, participants further reported the quality of the generated mediator (e.g., images, sentences for each word pair. We observed task-selective memory effects for visual imagery in the left middle occipital gyrus, the left precuneus, and the lingual gyrus. No such task-selective effects were observed for sentence generation. Intriguingly, activity at the time of study in the left precuneus was modulated by the self-reported quality (vividness of the generated mental images with greater activity for trials given higher ratings of quality. These data suggest that regions of the brain support memory in accord with the encoding operations engaged at the time of study.

  14. Weak Pullback Attractors for Asymptotically Upper Semicompact Nonautonomous Multivalued Semiflow%渐近上半紧的非自治多值半流的弱拉回吸引子

    Institute of Scientific and Technical Information of China (English)

    李挺; 廖公夫

    2006-01-01

    @@ 1 Introduction In this paper we study the existence of pullback attractors for multivalued nonantonomous and multivalued random semiflow. In [1] and [2], the authors have proved the existence of pullback attractors of multivalued nonautonomous semiflow (random semiflow) under the assumption of the existence of compact absorbing set. In [3], the authors have proved the existence of pullback attractors of multivalued nonautonomous semiflow and random semiflow under the assumptions of uniformly pullback asymptotically upper semicompact and closed graph. In [4], the authors consider the existence of pullback attractor of singlevalued nonautonomous semiflow and random semiflow under the assumption of pullback asymptotic compactness. Instead of these assumptions, we consider multivalued nonautonomous semiflow and multivalued random semiflow with weak pullback asymptotic upper semi-compactness and prove the existence of pullback attractors.

  15. Effects of Sleep Deprivation and Aging on Long-Term and Remote Memory in Mice

    Science.gov (United States)

    Vecsey, Christopher G.; Park, Alan J.; Khatib, Nora; Abel, Ted

    2015-01-01

    Sleep deprivation (SD) following hippocampus-dependent learning in young mice impairs memory when tested the following day. Here, we examined the effects of SD on remote memory in both young and aged mice. In young mice, we found that memory is still impaired 1 mo after training. SD also impaired memory in aged mice 1 d after training, but, by a…

  16. Effects of Sleep Deprivation and Aging on Long-Term and Remote Memory in Mice

    Science.gov (United States)

    Vecsey, Christopher G.; Park, Alan J.; Khatib, Nora; Abel, Ted

    2015-01-01

    Sleep deprivation (SD) following hippocampus-dependent learning in young mice impairs memory when tested the following day. Here, we examined the effects of SD on remote memory in both young and aged mice. In young mice, we found that memory is still impaired 1 mo after training. SD also impaired memory in aged mice 1 d after training, but, by a…

  17. Ishikawa Iterative Process for a Pair of Single-valued and Multivalued Nonexpansive Mappings in Banach Spaces

    Directory of Open Access Journals (Sweden)

    Kaewkhao A

    2010-01-01

    Full Text Available Let be a nonempty compact convex subset of a uniformly convex Banach space , and let and be a single-valued nonexpansive mapping and a multivalued nonexpansive mapping, respectively. Assume in addition that and for all . We prove that the sequence of the modified Ishikawa iteration method generated from an arbitrary by , , where and , are sequences of positive numbers satisfying , , converges strongly to a common fixed point of and ; that is, there exists such that .

  18. Convergence Theorem for Generalized Mixed Equilibrium Problem and Common Fixed Point Problem for a Family of Multivalued Mappings

    Directory of Open Access Journals (Sweden)

    J. N. Ezeora

    2016-01-01

    Full Text Available In this paper, a new hybrid iterative algorithm is constructed using the shrinking projection method introduced by Takahashi. The sequence of the algorithm is proved to converge strongly to a common element of the set of solutions of generalized mixed equilibrium problem and the set of common fixed points of a finite family of multivalued strictly pseudocontractive mappings in real Hilbert spaces. Furthermore, we apply our main result to convex minimization problem.

  19. Quantum anomalous Hall effect in topological insulator memory

    Energy Technology Data Exchange (ETDEWEB)

    Jalil, Mansoor B. A., E-mail: elembaj@nus.edu.sg [Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore, Singapore 117576 (Singapore); Data Storage Institute, Agency for Science, Technology and Research A*STAR, DSI Building, 5 Engineering Drive 1, Singapore, Singapore 117608 (Singapore); Tan, S. G. [Data Storage Institute, Agency for Science, Technology and Research A*STAR, DSI Building, 5 Engineering Drive 1, Singapore, Singapore 117608 (Singapore); Department of Electrical and Computer Engineering, National University of Singapore, 4 Engineering Drive 3, Singapore, Singapore 117576 (Singapore); Siu, Z. B. [Data Storage Institute, Agency for Science, Technology and Research A*STAR, DSI Building, 5 Engineering Drive 1, Singapore, Singapore 117608 (Singapore); NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore (Singapore)

    2015-05-07

    We theoretically investigate the quantum anomalous Hall effect (QAHE) in a magnetically coupled three-dimensional-topological insulator (3D-TI) system. We apply the generalized spin-orbit coupling Hamiltonian to obtain the Hall conductivity σ{sup xy} of the system. The underlying topology of the QAHE phenomenon is then analyzed to show the quantization of σ{sup xy} and its relation to the Berry phase of the system. Finally, we analyze the feasibility of utilizing σ{sup xy} as a memory read-out in a 3D-TI based memory at finite temperatures, with comparison to known magnetically doped 3D-TIs.

  20. Dynamics of Quantum Entanglement in Reservoir with Memory Effects

    Institute of Scientific and Technical Information of China (English)

    郝翔; 沙金巧; 孙坚; 朱士群

    2012-01-01

    The non-Markovian dynamics of quantum entanglement is studied by the Shabani-Lidar master equation when one of entangled quantum systems is coupled to a local reservoir with memory effects. The completely positive reduced dynamical map can be constructed in the Kraus representation. Quantum entanglement decays more slowly in the non-Markovian environment. The decoherence time for quantum entanglement can be markedly increased with the change of the memory kernel. It is found out that the entanglement sudden death between quantum systems and entanglement sudden birth between the system and reservoir occur at different instants.

  1. The quintuple-shape memory effect in electrospun nanofiber membranes

    Science.gov (United States)

    Zhang, Fenghua; Zhang, Zhichun; Liu, Yanju; Lu, Haibao; Leng, Jinsong

    2013-08-01

    Shape memory fibrous membranes (SMFMs) are an emerging class of active polymers, which are capable of switching from a temporary shape to their permanent shape upon appropriate stimulation. Quintuple-shape memory membranes based on the thermoplastic polymer Nafion, with a stable fibrous structure, are achieved via electrospinning technology, and possess a broad transition temperature. The recovery of multiple temporary shapes of electrospun membranes can be triggered by heat in a single triple-, quadruple-, quintuple-shape memory cycle, respectively. The fiber morphology and nanometer size provide unprecedented design flexibility for the adjustable morphing effect. SMFMs enable complex deformations at need, having a wide potential application field including smart textiles, artificial intelligence robots, bio-medical engineering, aerospace technologies, etc in the future.

  2. Memory conformity: exploring misinformation effects when presented by another person.

    Science.gov (United States)

    Wright, D B; Self, G; Justice, C

    2000-05-01

    Two experiments demonstrate that post-event information, when delivered by another person, can affect people's memory reports. In the first experiment participants were shown several cars, and later, in pairs, given an 'old'/'new' recognition test on these cars plus several lures. There was a small but reliable effect of memory conformity. When the person was given misinformation this lowered accuracy, while presenting accurate information increased accuracy. In the second experiment participants, in pairs, viewed an identical crime except that half saw an accomplice with the thief and half did not. Initial memories were very accurate, but after discussing the crime with the other person in the pair (who saw a slightly different sequence), most pairs conformed. Confidence ratings strongly predicted which person in the pair persuaded the other. Parallels with eyewitness testimony in the Oklahoma bombing case and implications for police interviewing more generally are discussed.

  3. Effect of memory in non-Markovian Boolean networks

    CERN Document Server

    Ebadi, Haleh; Ausloos, Marcel; Jafari, GholamReza

    2016-01-01

    One successful model of interacting biological systems is the Boolean network. The dynamics of a Boolean network, controlled with Boolean functions, is usually considered to be a Markovian (memory-less) process. However, both self organizing features of biological phenomena and their intelligent nature should raise some doubt about ignoring the history of their time evolution. Here, we extend the Boolean network Markovian approach: we involve the effect of memory on the dynamics. This can be explored by modifying Boolean functions into non-Markovian functions, for example, by investigating the usual non-Markovian threshold function, - one of the most applied Boolean functions. By applying the non-Markovian threshold function on the dynamical process of a cell cycle network, we discover a power law memory with a more robust dynamics than the Markovian dynamics.

  4. SHAPE MEMORY EFFECT OF SLIGHTLY-CROSSLINKED POLYETHYLENE

    Institute of Scientific and Technical Information of China (English)

    1998-01-01

    A series of slightly crosslinked polyethylenes (SXLPE) was prepared by a one-step method using dicumyl peroxide as crosslinking agent in a Haake Mixer. The gel contents G (Soxhlet extracted) of the samples are in the range from 5% to 20% by weight.Their shear viscosity, crystallization and melting behavior, dynamic mechanical properties and shape recovery effect were systematically investigated in terms of the content of the crosslinking agent. It shows that under certain experimental conditions the SXLPE's may exhibit good shape fixation ability and shape memory properties, which are similar to those of the commercially available shape memory polyethylenes prepared by gamma-irradiation technique. However the shape memory behavior of these samples is not very stable due to their low crosslinking degree, or gel content. Thus their application is limited in special cases with fast strain fixing procedures.

  5. Vantage perspective during encoding: The effects on phenomenological memory characteristics

    NARCIS (Netherlands)

    Mooren, N.; Krans, J.; Näring, G.W.B.; Moulds, M.L.; Minnen, A. van

    2016-01-01

    The vantage perspective from which a memory is retrieved influences the memory’s emotional impact, intrusiveness, and phenomenological characteristics. This study tested whether similar effects are observed when participants were instructed to imagine the events from a specific perspective. Fifty st

  6. THE EFFECT OF MEMORY TERMS IN DIFFUSION PHENOMENA

    Institute of Scientific and Technical Information of China (English)

    A. Araújo; J.A. Ferreira; P. Oliveira

    2006-01-01

    In this paper the effect of integral memory terms in the behavior of diffusion phenomena is studied. The energy functional associated with different models is analyzed and stability inequalities are established. Approximation methods for the computation of the solution of the integro-differential equations are constructed. Numerical results are included.

  7. Memory effect in the high-temperature superconducting bulks

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xing-Yi, E-mail: zhangxingyi@lzu.edu.cn; Zhou, Jun; Zhou, You-He

    2013-12-15

    Highlights: •Effects of temperature cycles on levitation force relaxation are investigated. •Memory effect of the YBCO bulks is observed in experiments. •With an increase of temperature, memory of the superconductor is gradually lost. -- Abstract: We present an experimental investigation of the relaxation of vertical force components in a high-temperature superconducting levitation system with different temperature cycle processes. For a selected ambient temperature (T{sub 1}) of the system, the experimental results show that the relaxations of the levitation forces are strongly dependent on the initial temperature. When the sample was submitted to temperature jumps around T{sub 1}, the sample temperature was regulated at T{sub 2}, and there were two cases of the experiments, ΔT = T{sub 2} − T{sub 1} < 0 (negative temperature cycle) and ΔT > 0 (positive temperature cycle). It was found that in the case of negative temperature cycle, the superconducting samples have memory effect. And for the positive temperature cycle, with the experimental temperature increase, the memory effect of samples is gradually losing. Additionally, with the increase of temperature, the influences of the negative and positive temperature cycle on the levitation force relaxation are unsymmetrical. All the results are interpreted by using the characteristics of the free energy ‘ground’ plot of the Spin-glasses qualitatively.

  8. Quantum noise memory effect of multiple scattered light

    CERN Document Server

    Lodahl, P

    2005-01-01

    We investigate frequency correlations in multiple scattered light that are present in the quantum fluctuations. The memory effect for quantum and classical noise is compared, and found to have markedly different frequency scaling, which was confirmed in a recent experiment. Furthermore, novel mesoscopic correlations are predicted that depend on the photon statistics of the incoming light.

  9. Effect of antidepressants on spatial memory deficit induced by dizocilpine.

    Science.gov (United States)

    Tao, Chenjuan; Yan, Weiwei; Li, Yuan; Lu, Xiaodong

    2016-10-30

    Cognitive deficits are a core symptom of schizophrenia. It is controversial whether antidepressants could improve cognitive symptoms in schizophrenia patients. The present study was designed to identify the therapeutic effect of antidepressants on cognitive deficits in schizophrenia. In the present study, adolescent rats were repeatedly exposed to dizocilpine, which can induce cognitive deficits associated with schizophrenia. Then these rats were treated by six antidepressants (fluvoxamine, sertraline, paroxetine, escitalopram, venlafaxine, mirtazapine) or vehicle. The rats in the control group were exposed to vehicle during the study. Lastly, all rats' spatial memory (a major part of cognition) was assessed using the Morris water maze (MWM) test, and the density of hippocampal parvalbumin (PV) interneurons was evaluated to explore possible mechanisms underlying spatial memory change in schizophrenia. The results of the present study supported the hypothesis of a therapeutic effect of fluvoxamine and escitalopram on spatial memory deficit induced by dizocilpine. Additionally, the data of the present study suggested that fluvoxamine and escitalopram remitted hippocampal PV interneuron reduction induced by dizocilpine. The neuroprotective effect of fluvoxamine and escitalopram may partly explain the therapeutic effect of antidepressants on spatial memory deficit in schizophrenia patients.

  10. The Origin of Vibration Redemption Effect for Shape Memory Alloys

    Directory of Open Access Journals (Sweden)

    Daniel Amariei

    2007-10-01

    Full Text Available Shape memory alloys (SMA components can affect through two mechanisms the vibrations of structures. The stresses from a SMA element that realize phase transformations, as a result of vibrations, have an effect on the frequency-amplitude characteristics. In addition, a dissipation of energy due to hysteresis in a SMA element can reduce the natural frequency and affect forced vibrations.

  11. Memory Effects and Scaling Laws in Slowly Driven Systems

    CERN Document Server

    Berglund, N

    1999-01-01

    This article deals with dynamical systems depending on a slowly varying parameter. We present several physical examples illustrating memory effects, such as metastability and hysteresis, which frequently appear in these systems. A mathematical theory is outlined, which allows to show existence of hysteresis cycles, and determine related scaling laws.

  12. Effects of Skill Training on Working Memory Capacity

    Science.gov (United States)

    Lee, Yuh-shiow; Lu, Min-ju; Ko, Hsiu-ping

    2007-01-01

    In this study we examined the effects of skill training, in particular mental abacus and music training, on working memory. Two groups of participants--children who had received mental abacus training and their controls--participated in Experiment 1. All participants performed the following span tasks: forward digit span, backward digit span,…

  13. Effects of Skill Training on Working Memory Capacity

    Science.gov (United States)

    Lee, Yuh-shiow; Lu, Min-ju; Ko, Hsiu-ping

    2007-01-01

    In this study we examined the effects of skill training, in particular mental abacus and music training, on working memory. Two groups of participants--children who had received mental abacus training and their controls--participated in Experiment 1. All participants performed the following span tasks: forward digit span, backward digit span,…

  14. Effects of Aging and IQ on Item and Associative Memory

    Science.gov (United States)

    Ratcliff, Roger; Thapar, Anjali; McKoon, Gail

    2011-01-01

    The effects of aging and IQ on performance were examined in 4 memory tasks: item recognition, associative recognition, cued recall, and free recall. For item and associative recognition, accuracy and the response time (RT) distributions for correct and error responses were explained by Ratcliff's (1978) diffusion model at the level of individual…

  15. The Effect of Modality on Long-Term Recognition Memory.

    Science.gov (United States)

    Dean, Raymond S.; And Others

    1988-01-01

    The effects of visual and auditory modes of input on long-term memory were examined in two experiments, each with 40 and 80 undergraduates, respectively. In both experiments, visual stimulus attributes were a more salient dimension than were auditory features in the long-term encoding and retrieval process. (SLD)

  16. Effect of background music on auditory-verbal memory performance

    Directory of Open Access Journals (Sweden)

    Sona Matloubi

    2014-12-01

    Full Text Available Background and Aim: Music exists in all cultures; many scientists are seeking to understand how music effects cognitive development such as comprehension, memory, and reading skills. More recently, a considerable number of neuroscience studies on music have been developed. This study aimed to investigate the effects of null and positive background music in comparison with silence on auditory-verbal memory performance.Methods: Forty young adults (male and female with normal hearing, aged between 18 and 26, participated in this comparative-analysis study. An auditory and speech evaluation was conducted in order to investigate the effects of background music on working memory. Subsequently, the Rey auditory-verbal learning test was performed for three conditions: silence, positive, and null music.Results: The mean score of the Rey auditory-verbal learning test in silence condition was higher than the positive music condition (p=0.003 and the null music condition (p=0.01. The tests results did not reveal any gender differences.Conclusion: It seems that the presence of competitive music (positive and null music and the orientation of auditory attention have negative effects on the performance of verbal working memory. It is possibly owing to the intervention of music with verbal information processing in the brain.

  17. Vantage perspective during encoding: The effects on phenomenological memory characteristics

    NARCIS (Netherlands)

    Mooren, N.; Krans, J.; Näring, G.W.B.; Moulds, M.L.; Minnen, A. van

    2016-01-01

    The vantage perspective from which a memory is retrieved influences the memory’s emotional impact, intrusiveness, and phenomenological characteristics. This study tested whether similar effects are observed when participants were instructed to imagine the events from a specific perspective. Fifty

  18. Delayed effects of cortisol enhance fear memory of trace conditioning.

    Science.gov (United States)

    Cornelisse, Sandra; van Ast, Vanessa A; Joëls, Marian; Kindt, Merel

    2014-02-01

    Corticosteroids induce rapid non-genomic effects followed by slower genomic effects that are thought to modulate cognitive function in opposite and complementary ways. It is presently unknown how these time-dependent effects of cortisol affect fear memory of delay and trace conditioning. This distinction is of special interest because the neural substrates underlying these types of conditioning may be differently affected by time-dependent cortisol effects. Delay conditioning is predominantly amygdala-dependent, while trace conditioning additionally requires the hippocampus. Here, we manipulated the timing of cortisol action during acquisition of delay and trace fear conditioning, by randomly assigning 63 men to one of three possible groups: (1) receiving 10mg hydrocortisone 240 min (slow cort) or (2) 60 min (rapid cort) before delay and trace acquisition, or (3) placebo at both times, in a double-blind design. The next day, we tested memory for trace and delay conditioning. Fear potentiated startle responses, skin conductance responses and unconditioned stimulus expectancy scores were measured throughout the experiment. The fear potentiated startle data show that cortisol intake 240 min before actual fear acquisition (slow cort) uniquely strengthened subsequent trace conditioned memory. No effects of cortisol delivery 60 min prior to fear acquisition were found on any measure of fear memory. Our findings emphasize that slow, presumably genomic, but not more rapid effects of corticosteroids enhance hippocampal-dependent fear memories. On a broader level, our findings underline that basic experimental research and clinically relevant pharmacological treatments employing corticosteroids should acknowledge the timing of corticosteroid administration relative to the learning phase, or therapeutic intervention.

  19. Differential effects of ecstasy on short-term and working memory: a meta-analysis.

    Science.gov (United States)

    Nulsen, Claire E; Fox, Allison M; Hammond, Geoffrey R

    2010-03-01

    Quantitative analysis of studies examining the effect of ecstasy on short-term and working memory in the verbal and visuo-spatial domain was undertaken. Thirty verbal short-term memory, 22 verbal working memory, 12 visuospatial short-term memory and 9 visuospatial working memory studies met inclusion criteria. Ecstasy users performed significantly worse in all memory domains, both in studies using drug-naïve controls and studies using polydrug controls. These results are consistent with previous meta-analytic findings that ecstasy use is associated with impaired short-term memory function. Lifetime ecstasy consumption predicted effect size in working memory but not in short-term memory. The current meta-analysis adds to the literature by showing that ecstasy use in humans is also associated with impaired working memory, and that this impairment is related to total lifetime ecstasy consumption. These findings highlight the long-term, cumulative behavioral consequences associated with ecstasy use in humans.

  20. Experimental study on radiation effects in floating gate read-only-memories and static random access memories

    Institute of Scientific and Technical Information of China (English)

    He Chao-Hui; Li Yong-Hong

    2007-01-01

    Radiation effects of the floating gate read-only-memory (FG ROM) and the static random access memory (SRAM)have been evaluated using the 14 MeV neutron and 31.9MeV proton beams and Co-60 γ-rays. The neutron fluence,when the first error occurs in the FG ROMs, is at least 5 orders of magnitude higher than that in the SRAMs, and the proton fluence, 4 orders of magnitude higher. The total dose threshold for Co-60 γ-ray irradiation is about 104 rad (Si)for both memories. The difference and similarity are attributed to the structure of the memory cells and the mechanism of radiation effects. It is concluded that the FG ROMs are more reliable as semiconductor memories for storing data than the SRAMs, when they are used in the satellites or space crafts exposed to high energy particle radiation.

  1. Time-dependent effects of cortisol on the contextualization of emotional memories.

    Science.gov (United States)

    van Ast, Vanessa A; Cornelisse, Sandra; Meeter, Martijn; Joëls, Marian; Kindt, Merel

    2013-12-01

    The inability to store fearful memories into their original encoding context is considered to be an important vulnerability factor for the development of anxiety disorders like posttraumatic stress disorder. Altered memory contextualization most likely involves effects of the stress hormone cortisol, acting via receptors located in the memory neurocircuitry. Cortisol via these receptors induces rapid nongenomic effects followed by slower genomic effects, which are thought to modulate cognitive function in opposite, complementary ways. Here, we targeted these time-dependent effects of cortisol during memory encoding and tested subsequent contextualization of emotional and neutral memories. In a double-blind, placebo-controlled design, 64 men were randomly assigned to one of three groups: 1) received 10 mg hydrocortisone 30 minutes (rapid cortisol effects) before a memory encoding task; 2) received 10 mg hydrocortisone 210 minutes (slow cortisol) before a memory encoding task; or 3) received placebo at both times. During encoding, participants were presented with neutral and emotional words in unique background pictures. Approximately 24 hours later, context dependency of their memories was assessed. Recognition data revealed that cortisol's rapid effects impair emotional memory contextualization, while cortisol's slow effects enhance it. Neutral memory contextualization remained unaltered by cortisol, irrespective of the timing of the drug. This study shows distinct time-dependent effects of cortisol on the contextualization of specifically emotional memories. The results suggest that rapid effects of cortisol may lead to impaired emotional memory contextualization, while slow effects of cortisol may confer protection against emotional memory generalization. © 2013 Society of Biological Psychiatry.

  2. Methods for obtaining two way memory effect and stressed two way memory effect of CuAlNi single crystals

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Various training methods for two way memory effect (TWME) and stressed two way memory effect (STWME) were tried on Cu-13.4Al-4.0Ni (mass fraction, %) single crystals by applying tensile stress along 〈001〉 direction of β phase. The training method of cooling with load can induce a lot of martensite prone to stabilize, thus cause large residual deformation, wide hysteresis and small TWME. Training with constant load can produce STWME larger than 8% with the least residual deformation. By training procedure of martensite reorientation below Mf followed by thermal cycling, the TWME is relatively large with very small residual deformation and with comparatively narrow hysteresis of two-way memory. The obtained two-way memory curve after such training is not a closed loop, and the obtained TWME is not stable. However, these can be improved by thermal cycling. Training with martensite reorientation below Mf and thermal cycling under relatively low constant stress throughout the whole training procedure is the optimum way of obtaining TWME, and more than 1.7% TWME can be obtained. The thermomechanical history of the sample has a pronounced effect on the training result. Thermomechanical cycling has a softening effect on martensite.

  3. Modulatory mechanisms of cortisol effects on emotional learning and memory: Novel perspectives

    OpenAIRE

    Vanessa A. van Ast; Cornelisse, Sandra; Marin, Marie-France; Ackermann, Sandra; Garfinkel, Sara; Abercrombie, Heather C.

    2013-01-01

    It has long been known that cortisol affects learning and memory processes. Despite a wealth of research dedicated to cortisol effects on learning and memory, the strength or even directionality of the effects often vary. A number of the factors that alter cortisol’s effects on learning and memory are well-known. For instance, effects of cortisol can be modulated by emotional arousal and the memory phase under study. Despite great advances in understanding factors that explain variability in ...

  4. Memory effects on descent from nuclear fission barrier

    CERN Document Server

    Kolomietz, V M; Shlomo, S

    2001-01-01

    Non-Markovian transport equations for nuclear large amplitude motion are derived from the collisional kinetic equation. The memory effects are caused by the Fermi surface distortions and depend on the relaxation time. It is shown that the nuclear collective motion and the nuclear fission are influenced strongly by the memory effects at the relaxation time $\\tau \\geq 5\\cdot 10^{-23}{\\rm s}$. In particular, the descent of the nucleus from the fission barrier is accompanied by characteristic shape oscillations. The eigenfrequency and the damping of the shape oscillations depend on the contribution of the memory integral in the equations of motion. The shape oscillations disappear at the short relaxation time regime at $\\tau \\to 0$, which corresponds to the usual Markovian motion in the presence of friction forces. We show that the elastic forces produced by the memory integral lead to a significant delay for the descent of the nucleus from the barrier. Numerical calculations for the nucleus $^{236}$U shows that ...

  5. Ageing and the group-reference effect in memory.

    Science.gov (United States)

    Lee, Hyeon-Nyeon; Rosa, Nicole M; Gutchess, Angela H

    2016-07-01

    The present study examines age differences in the memory benefits from group-referncing. While prior work establishes that the memory performance of younger and older adults similarly benefits from relating information to the self, this study assessed whether those benefits extend to referencing a meaningful group membership. Young and older adult participants encoded trait words by judging whether each word describes themselves, describes their group membership (selected for each age group), or is familiar. After a retention interval, participants completed a surprise recognition memory test. The results indicate that group-referencing increased recognition memory performance compared to the familiarity judgements for both young and older groups. However, the group-reference benefit is limited, emerging as smaller than the benefit from self-referencing. These results challenge previous findings of equivalent benefits for group-referencing and self-referencing, suggesting that such effects may not prevail under all conditions, including for older adults. The findings also highlight the need to examine the mechanisms of group-referencing that can lead to variability in the group-reference effect.

  6. Effect of emotion on memory for words and their context.

    Science.gov (United States)

    Riegel, Monika; Wierzba, Małgorzata; Grabowska, Anna; Jednoróg, Katarzyna; Marchewka, Artur

    2016-06-01

    Emotion influences various cognitive processes, such as memory. This beneficial or detrimental effect can be studied with verbal material, yet in this case a broad term of context has to be taken into account. The present work reviews recent literature and proposes that traditional differentiation between semantic and environmental context should be replaced with a novel conceptualization of hippocampus-dependent relational memory and item memory (related to the activations of cuneus and left amygdala). Additionally, instead of list-learning paradigms, words should be memorized in the context of sentences or stories for better control over their meaning. The recent evidence suggests that of particular importance for ecological validity in research paradigms is the presence of communicative and social context of verbal material related to such processes as theory of mind and brain activations in temporoparietal junction, posterior cingulate cortex, and dorsal medial prefrontal cortex. We propose that studying memory of verbal material within context gives a better understanding of enhancing and impairing effects of emotion as well as of the underlying brain mechanisms.

  7. Effects of arginine vasopressin on musical working memory.

    Science.gov (United States)

    Granot, Roni Y; Uzefovsky, Florina; Bogopolsky, Helena; Ebstein, Richard P

    2013-01-01

    Previous genetic studies showed an association between variations in the gene coding for the 1a receptor of the neuro-hormone arginine vasopressin (AVP) and musical working memory (WM). The current study set out to test the influence of intranasal administration (INA) of AVP on musical as compared to verbal WM using a double blind crossover (AVP-placebo) design. Two groups of 25 males were exposed to 20 IU of AVP in one session, and 20 IU of saline water (placebo) in a second session, 1 week apart. In each session subjects completed the tonal subtest from Gordon's "Musical Aptitude Profile," the interval subtest from the "Montreal Battery for Evaluation of Amusias (MBEA)," and the forward and backward digit span tests. Scores in the digit span tests were not influenced by AVP. In contrast, in the music tests there was an AVP effect. In the MBEA test, scores for the group receiving placebo in the first session (PV) were higher than for the group receiving vasopressin in the first session (VP) (p affect scale, (PANAS). Only in this group and only in the music test these scores were significantly correlated with memory scores. Together the results reflect a complex interaction between AVP, musical memory, arousal, and contextual effects such as session, and base levels of memory. The results are interpreted in light of music's universal use as a means to modulate arousal on the one hand, and AVP's influence on mood, arousal, and social interactions on the other.

  8. Memory-effect-induced macroscopic-microscopic entanglement

    Science.gov (United States)

    Mu, Qingxia; Zhao, Xinyu; Yu, Ting

    2016-07-01

    We study optomechanical entanglement between an optical cavity field and a movable mirror coupled to a non-Markovian environment. The non-Markovian quantum-state diffusion approach and the non-Markovian master equation are shown to be useful in investigating entanglement generation between the cavity field and the movable mirror. The simple model presented in this paper demonstrates several interesting properties of optomechanical entanglement that are associated with environment memory effects. It is evident that the effective environment central frequency can be used to modulate the optomechanical entanglement. In addition, we show that the maximum entanglement may be achieved by properly choosing the effective detuning, which is significantly dependent on the strength of the memory effect of the environment.

  9. MEMORY MODULATION

    Science.gov (United States)

    Roozendaal, Benno; McGaugh, James L.

    2011-01-01

    Our memories are not all created equally strong: Some experiences are well remembered while others are remembered poorly, if at all. Research on memory modulation investigates the neurobiological processes and systems that contribute to such differences in the strength of our memories. Extensive evidence from both animal and human research indicates that emotionally significant experiences activate hormonal and brain systems that regulate the consolidation of newly acquired memories. These effects are integrated through noradrenergic activation of the basolateral amygdala which regulates memory consolidation via interactions with many other brain regions involved in consolidating memories of recent experiences. Modulatory systems not only influence neurobiological processes underlying the consolidation of new information, but also affect other mnemonic processes, including memory extinction, memory recall and working memory. In contrast to their enhancing effects on consolidation, adrenal stress hormones impair memory retrieval and working memory. Such effects, as with memory consolidation, require noradrenergic activation of the basolateral amygdala and interactions with other brain regions. PMID:22122145

  10. Modulatory mechanisms of cortisol effects on emotional learning and memory: Novel perspectives

    NARCIS (Netherlands)

    Ast, V.A. van; Cornelisse, S.; Marin, M.F.; Ackermann, S.; Garfinkel, S.N.; Abercrombie, H.C.

    2013-01-01

    It has long been known that cortisol affects learning and memory processes. Despite a wealth of research dedicated to cortisol effects on learning and memory, the strength or even directionality of the effects often vary. A number of the factors that alter cortisol's effects on learning and memory a

  11. Hormones, stress, and cognition: The effects of glucocorticoids and oxytocin on memory

    Science.gov (United States)

    Wirth, Michelle M.

    2014-01-01

    Hormones have nuanced effects on learning and memory processes. The degree and direction of the effect (e.g., is memory impaired or enhanced?) depends on the dose, type and stage of memory, and type of material being learned, among other factors. This review will focus on two specific topics within the realm of effects of hormones on memory: (1) How glucocorticoids (the output hormones of the hypothalamic-pituitary-adrenal axis) affect long-term memory consolidation, retrieval, and working memory, with a focus on neural mechanisms and effects of emotion; and (2) How oxytocin affects memory, with emphasis on a speculative hypothesis that oxytocin might exert its myriad effects on human social cognition and behavior via impacts on more general cognitive processes. Oxytocin-glucocorticoid interactions will be briefly addressed. These effects of hormones on memory will also be considered from an evolutionary perspective. PMID:25893159

  12. Single-valued definition of the multivalued function for borehole acoustic waves in transversely isotropic formations

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    It is useful to extract all components, including compressional, shear, and guided waves, from the full waveforms when we investigate the acoustic log data. The component waves can be simulated by calculating the contributions from poles and branch points of the borehole acoustic function according to Cauchy’s theorem. For such an algorithm to be implemented, the multivalued function for the borehole wave field in the frequency-axial-wavenumber domain has to be rendered single-valued first. Assuming that the borehole axis is parallel to the symmetry axis of transverse isotropy, this paper derives the branch points of the borehole acoustic function. We discover that the number and the locations of those branch points are determined by the relation among the formation parameters c33, c44, ε, and δ. Thus the single-valued definitions in the acoustic-wave computation are sorted into two different cases. After building the Riemann surface related to each radial wavenumber, we give the single-valued definition of the borehole acoustic function inside and on the integration contour based on the radiation condition. In a formation with δ > ε + c44/2c33, if we choose the integration contour and the single-valued definition of the acoustic function in the way used in isotropic cases, the simulation results of component waves will be wrong.

  13. A coupled multivalued model for ice streams and its numerical simulation

    Science.gov (United States)

    Calvo, Nati; Durany, Jose; Munoz, Ana I.; Schiavi, Emanuele; Vazquez, Carlos

    2006-02-01

    This paper deals with the numerical solution of a non-linear model describing a free-boundary problem arising in modern glaciology. Considering a shallow, viscous ice sheet flow along a soft, deformable bed, a coupled non-linear system of differential equations can be obtained. Particularly, an obstacle problem is then deduced and solved in the framework of its complementarity formulation. We present the numerical solution of the resulting multivalued system modelling the ice sheet non-Newtonian dynamics driven by the underlying drainage system. Our numerical results show the existence of fast ice streams when positive wave-like initial conditions are considered. The solutions are numerically computed with a decoupling iterative method and finite-element technique. A duality algorithm and a projected Gauss-Seidel method are the alternatives used to cope with the resulting variational inequality while the explicit treatment, Newton method or a duality method are proposed to deal with the non-linear source term. Finally, the numerical solutions are physically interpreted and some comparisons among the numerical methods are then discussed.

  14. Effective visual working memory capacity: an emergent effect from the neural dynamics in an attractor network.

    Directory of Open Access Journals (Sweden)

    Laura Dempere-Marco

    Full Text Available The study of working memory capacity is of outmost importance in cognitive psychology as working memory is at the basis of general cognitive function. Although the working memory capacity limit has been thoroughly studied, its origin still remains a matter of strong debate. Only recently has the role of visual saliency in modulating working memory storage capacity been assessed experimentally and proved to provide valuable insights into working memory function. In the computational arena, attractor networks have successfully accounted for psychophysical and neurophysiological data in numerous working memory tasks given their ability to produce a sustained elevated firing rate during a delay period. Here we investigate the mechanisms underlying working memory capacity by means of a biophysically-realistic attractor network with spiking neurons while accounting for two recent experimental observations: 1 the presence of a visually salient item reduces the number of items that can be held in working memory, and 2 visually salient items are commonly kept in memory at the cost of not keeping as many non-salient items. Our model suggests that working memory capacity is determined by two fundamental processes: encoding of visual items into working memory and maintenance of the encoded items upon their removal from the visual display. While maintenance critically depends on the constraints that lateral inhibition imposes to the mnemonic activity, encoding is limited by the ability of the stimulated neural assemblies to reach a sufficiently high level of excitation, a process governed by the dynamics of competition and cooperation among neuronal pools. Encoding is therefore contingent upon the visual working memory task and has led us to introduce the concept of effective working memory capacity (eWMC in contrast to the maximal upper capacity limit only reached under ideal conditions.

  15. Effective visual working memory capacity: an emergent effect from the neural dynamics in an attractor network.

    Science.gov (United States)

    Dempere-Marco, Laura; Melcher, David P; Deco, Gustavo

    2012-01-01

    The study of working memory capacity is of outmost importance in cognitive psychology as working memory is at the basis of general cognitive function. Although the working memory capacity limit has been thoroughly studied, its origin still remains a matter of strong debate. Only recently has the role of visual saliency in modulating working memory storage capacity been assessed experimentally and proved to provide valuable insights into working memory function. In the computational arena, attractor networks have successfully accounted for psychophysical and neurophysiological data in numerous working memory tasks given their ability to produce a sustained elevated firing rate during a delay period. Here we investigate the mechanisms underlying working memory capacity by means of a biophysically-realistic attractor network with spiking neurons while accounting for two recent experimental observations: 1) the presence of a visually salient item reduces the number of items that can be held in working memory, and 2) visually salient items are commonly kept in memory at the cost of not keeping as many non-salient items. Our model suggests that working memory capacity is determined by two fundamental processes: encoding of visual items into working memory and maintenance of the encoded items upon their removal from the visual display. While maintenance critically depends on the constraints that lateral inhibition imposes to the mnemonic activity, encoding is limited by the ability of the stimulated neural assemblies to reach a sufficiently high level of excitation, a process governed by the dynamics of competition and cooperation among neuronal pools. Encoding is therefore contingent upon the visual working memory task and has led us to introduce the concept of effective working memory capacity (eWMC) in contrast to the maximal upper capacity limit only reached under ideal conditions.

  16. Memory effects in dissipative nucleus-nucleus collision

    CERN Document Server

    Yadav, H L

    2002-01-01

    A macroscopic dynamical model within the framework of a multidimensional Fokker-Planck equation is employed for a theoretical description of low-energy dissipative collisions between two heavy nuclei. The effect of two-body collisions leading to intrinsic equilibrium has been treated phenomenologically using the basic concepts of dissipative diabatic dynamics. The heavy-ion reaction sup 8 sup 6 Kr(8.18 MeV/u) + sup 1 sup 6 sup 6 Er has been as a prototype to study and demonstrate the memory effects for dissipation and diffusion processes. Our calculated results for the deflection angle, angular distributions d sigma/d theta sub c sub m , energy distributions d sigma/d DELTA EPSILON, and element distributions d sigma/d ZETA illustrate a remarkable dependence on the memory effects and are consistent with the experimental data

  17. Memory effects on mechanically stimulated electric signal; diversification of stimuli impact on material memory and comments on the observed features

    Science.gov (United States)

    Kyriazis, Panagiotis; Stavrakas, Ilias; Anastasiadis, Cimon; Triantis, Dimos; Stonham, John

    2010-05-01

    Memory is defined as the ability of marble and generally of brittle geomaterials to retain 'imprints' from previous treatments and to reproduce information about these treatments under certain conditions, by analogy to the memory of human beings. Memory effects have been observed in the evolution of a variety of physical properties like the acoustic emissions of brittle materials during fracture. The existence of memory effects for the mechanically stimulated electric signal, either by Pressure (PSC) or by Bending (BSC), is examined in this work, alongside with an attempt to distinguish between the two different manifestations of 'memory' based on the electrification mechanism that is triggered at different levels of externally applied load on samples. Having identified two main mechanisms (i.e. the dynamic and the cracking) and following the human memory model, we suggest the separation of memory of a material specimen into two levels i.e. the short or temporary and long or permanent memory. For the observation and analysis of the short memory of brittle materials we have conducted experiments using the PSC technique in marble specimens. The materials are imposed to cyclic stepwise loading of the same level, scheme and direction (axial stress - unchanged position of material) in order to comply with the conditions that are proposed as suitable for memory effects study by other researchers. We have also conducted experimental tests of cyclic high level stepwise loading on amphibolite rock specimens in order to verify and study the existence of permanent memory effects. Modelling the signal recordings and studying the effects of memory on the signals, we have identified certain trends manifestation for the two types of memory that are summarised to the following points. (a) Both types of memory influence the PSC peaks evolution (exponential decrease) in cyclic loadings of the same level. (b) Permanent memory cannot be erased and affects PSC signal permanently and

  18. Phase transformation behaviors and shape memory effects of TiNiFeAl shape memory alloys

    Institute of Scientific and Technical Information of China (English)

    Li Xiao; Fushun Liu; Huibin Xu

    2007-01-01

    Measurements of electrical resistivity, X-ray diffraction, and tensile test at room temperature and -196℃ were performed to investigate the effects of Al addition substituting Ni on the phase transformation behaviors, the mechanical properties, and the shape memory effects of Ti50Ni47Fe2Al1 and Ti50Ni46.5Fe2.5Al1 alloys. It is found that 1at% Al addition dramatically decreases the martensitic start transformation temperature and expands the transformation temperature range of R-phase for TiNiFeAl alloys. The results of tensile test indicate that 1at% Al improves the yield strength of Ti50Ni47Fe2Al1 and Ti50Ni46.5Fe2.5Al1 alloys by 40% and 64%, but decreases the plasticity to 11% and 12% from 26% and 27% respectively. Moreover, excellent shape memory effect of 6.6% and 7.5% were found in Ti50Ni47Fe2Al1 and Ti50Ni46.5Fe2.sAl1 alloys, which results from the stress-induced martensite transformation from the R-phase.

  19. Examination of the bidirectional influences of leisure activity and memory in old people: a dissociative effect on episodic memory.

    Science.gov (United States)

    Mousavi-Nasab, S-M-Hossein; Kormi-Nouri, Reza; Nilsson, Lars-Göran

    2014-08-01

    The present study examined the relationships between different types of social and cognitive activities and different types of episodic and semantic memory. A total of 794 adult men and women from five age cohorts (aged 65-85 at baseline), participating in the longitudinal Betula project on ageing, memory, and health, were included in the study. The participants were studied over 10 years (1995-2005) in three waves. Recognition and recall were used as episodic memory tasks, and knowledge and verbal fluency as semantic memory tasks. The results, after controlling for age, gender, education, and some diseases, including heart disease and hypertension, as covariates, showed unidirectional effects of social activity on episodic memory on all test occasions (β = .10). Also, episodic memory predicted change in cognitive activity for all test waves (β = .21-.22). Findings suggest that social activity can be seen as protective factor against memory decline. It also seems that episodic memory performance is a predictor of cognitive activity in old people. However, the opposite direction does not hold true.

  20. Effects of immune activation on the retrieval of spatial memory.

    Science.gov (United States)

    Huang, Zhen-Bo; Wang, Hao; Rao, Xiu-Rong; Liang, Tao; Xu, Jing; Cai, Xiang-Sheng; Sheng, Guo-Qing

    2010-10-01

    It has been shown that there are extensive interactions between the central nervous system and the immune system. The present study focused on the effects of lipopolysaccharide (LPS) on memory retrieval, to explore the interaction between immune activation and memory. C57BL/6J mice (8 weeks old) were first trained in the Morris water maze to reach asymptotic performance. Then mice were tested 24 h after the last training session and LPS was administered (1.25 mg/kg, i.p.) 4 h prior to the testing. The retrieval of spatial memory was tested by probe trial, and the time spent in the target quadrant and the number of platform location crosses were recorded. ELISA was performed to detect interleukin-1β (IL-1β) protein level in the hippocampus of mice tested in the water maze. Although LPS induced overt sickness behavior and a significant increase in the level of IL-1β in the hippocampus of mice, there was no significant difference in the time spent in the target quadrant or in the number of platform location crosses between LPS-treated and control groups in the probe trial testing. Immune activation induced by LPS does not impair the retrieval of spatial memory.

  1. Timing matters: temporal dynamics of stress effects on memory retrieval.

    Science.gov (United States)

    Schwabe, Lars; Wolf, Oliver T

    2014-09-01

    Stress may impair memory retrieval. This retrieval impairment has been attributed to the action of the stress hormone cortisol, which is released with a delay of several minutes after a stressful encounter. Hence, most studies tested memory retrieval 20-30 min after stress, when the stress-induced cortisol increase peaks. In the present experiment, we investigated whether retrieval impairments can also be found at later intervals after stress. To this end, participants learned a list of words on day 1. Twenty-four hours later, they were first exposed to a stressor or a nonstressful control manipulation and completed a recognition test for the words either immediately thereafter, 25 min later, or 90 min later. Our findings showed that stress did not impair memory retrieval when memory was tested immediately after the stressor, before cortisol levels were elevated. However, retrieval performance was impaired 25 min after stress, when cortisol levels peaked, as well as 90 min after the stressor, when cortisol levels had already returned to baseline. The retrieval impairment 90 min after stress appeared to be even stronger than the one after 25 min. These findings suggest that the detrimental effects of stress on retrieval performance may last longer than is usually assumed.

  2. Learning and memory promoting effects of crude garlic extract.

    Science.gov (United States)

    Mukherjee, Dhrubajyoti; Banerjee, Sugato

    2013-12-01

    Chronic administration of aged garlic extract has been shown to prevent memory impairment in mice. Acute and chronic (21 days) effects of marketed formulation of crude garlic extract (Lasuna) were evaluated on learning and memory in mice using step down latency (SDL) by passive avoidance response and transfer latency (TL) using elevated plus maze. Scopolamine (0.4 mg/kg, ip) was used to induce amnesia in mice and piracetam (200 mg/kg, ip) served as positive control. In the acute study, Lasuna (65 mg/kg, po) partially reversed the scopolamine-induced amnesia but failed to improve learning and memory in untreated animals. Chronic administration of Lasuna (40 mg/kg/day for 21 days) significantly improved learning both in control and scopolamine induced amnesic animals. Influence of Lasuna on central cholinergic activity and its antioxidant properties were also studied by estimating the cortical acetylcholinesterase (AchE) activity and reduced glutathione (GSH) levels respectively. Chronic administration of Lasuna inhibited AchE, while increasing GSH levels. Thus the results indicate that long-term administration of crude garlic extract may improve learning and memory in mice while the underlying mechanism of action may be attributed to the anti-AchE activity and anti-oxidant property of garlic.

  3. The hard fall effect: high working memory capacity leads to a higher, but less robust short-term memory performance.

    Science.gov (United States)

    Thomassin, Noémylle; Gonthier, Corentin; Guerraz, Michel; Roulin, Jean-Luc

    2015-01-01

    Participants with a high working memory span tend to perform better than low spans in a variety of tasks. However, their performance is paradoxically more impaired when they have to perform two tasks at once, a phenomenon that could be labeled the "hard fall effect." The present study tested whether this effect exists in a short-term memory task, and investigated the proposal that the effect is due to high spans using efficient facilitative strategies under simple task conditions. Ninety-eight participants performed a spatial short-term memory task under simple and dual task conditions; stimuli presentation times either allowed for the use of complex facilitative strategies or not. High spans outperformed low spans only under simple task conditions when presentation times allowed for the use of facilitative strategies. These results indicate that the hard fall effect exists on a short-term memory task and may be caused by individual differences in strategy use.

  4. Working memory capacity predicts effects of methylphenidate on reversal learning.

    Science.gov (United States)

    van der Schaaf, Marieke E; Fallon, Sean J; Ter Huurne, Niels; Buitelaar, Jan; Cools, Roshan

    2013-09-01

    Increased use of stimulant medication, such as methylphenidate, by healthy college students has raised questions about its cognitive-enhancing effects. Methylphenidate acts by increasing extracellular catecholamine levels and is generally accepted to remediate cognitive and reward deficits in patients with attention deficit hyperactivity disorder. However, the cognitive-enhancing effects of such 'smart drugs' in the healthy population are still unclear. Here, we investigated effects of methylphenidate (Ritalin, 20  mg) on reward and punishment learning in healthy students (N=19) in a within-subject, double-blind, placebo-controlled cross-over design. Results revealed that methylphenidate effects varied both as a function of task demands and as a function of baseline working memory capacity. Specifically, methylphenidate improved reward vs punishment learning in high-working memory subjects, whereas it impaired reward vs punishment learning in low-working memory subjects. These results contribute to our understanding of individual differences in the cognitive-enhancing effects of methylphenidate in the healthy population. Moreover, they highlight the importance of taking into account both inter- and intra-individual differences in dopaminergic drug research.

  5. Side Effects - Memory or Concentration Problems

    Science.gov (United States)

    Cancer treatments, such as chemo, may cause difficulty thinking, concentrating, or other cognitive problems. Learn about steps people with cancer can take to manage these side effects. See a list of helpful questions for families to ask the doctor.

  6. Cortisol has different effects on human memory for emotional and neutral stimuli.

    Science.gov (United States)

    Rimmele, Ulrike; Domes, Gregor; Mathiak, Klaus; Hautzinger, Martin

    2003-12-19

    Adrenal stress hormones are considered to play a role in memory enhancement of emotionally arousing events. To investigate the effects of cortisol on human emotional memory, subjects were administered hydrocortisone (25 mg) or placebo and presented with either an emotionally arousing or a neutral story. Memory for the story was tested 1 week later. In all memory tests, subjects who viewed the emotional story scored better for the emotionally arousing story parts, indicating that arousal enhances memory. In memory of details, cortisol showed an interaction with story valence but no main effect: cortisol enhanced memory for details of the neutral story version, but impaired memory for details of the emotionally arousing version. We thus confirm a non-linear interaction between cortisol and arousal on memory formation.

  7. Effects of Arginine Vasopressin on musical short-term memory

    Directory of Open Access Journals (Sweden)

    Roni Y. Granot

    2013-10-01

    Full Text Available Previous genetic studies showed an association between variations in the gene coding for the 1a receptor of the neuro-hormone arginine vasopressin (AVP and musical working memory (WM. The current study set out to test the influence of intranasal administration (INA of AVP on musical as compared to verbal WM using a double blind crossover (AVP – placebo design. Two groups of 25 males were exposed to 20 IU of AVP in one session, and 20 IU of saline water (placebo in a second session, one week apart. In each session subjects completed the tonal subtest from Gordon's Musical Aptitude Profile, the interval subtest from the Montreal Battery for Evaluation of Amusias (MBEA, and the forward and backward digit span tests. Scores in the digit span tests were not influenced by AVP. In contrast, in the music tests there was an AVP effect. In the MBEA test, scores for the group receiving placebo in the first session (PV were higher than for the group receiving vasopressin in the first session (VP (p < .05 with no main Session effect nor Group * Session interaction. In the Gordon test there was a main Session effect (p < .05 with scores higher in the second as compared to the first session, a marginal main Group effect (p = .093 and a marginal Group X Session interaction (p = 0.88. In addition we found that the group that received AVP in the first session scored higher on scales indicative of happiness, and alertness on the Positive and Negative Affect Scale, (PANAS. Only in this group and only in the music test these scores were significantly correlated with memory scores. Together the results reflect a complex interaction between AVP, musical memory, arousal, and contextual effects such as session, and base levels of memory. The results are interpreted in light of music's universal use as a means to modulate arousal on the one hand, and AVP's influence on mood, arousal, and social interactions on the other.

  8. Hippocampal NMDA receptors and the previous experience effect on memory.

    Science.gov (United States)

    Cercato, Magalí C; Colettis, Natalia; Snitcofsky, Marina; Aguirre, Alejandra I; Kornisiuk, Edgar E; Baez, María V; Jerusalinsky, Diana A

    2014-01-01

    N-methyl-D-aspartate receptors (NMDAR) are thought to be responsible for switching synaptic activity specific patterns into long-term changes in synaptic function and structure, which would support learning and memory. Hippocampal NMDAR blockade impairs memory consolidation in rodents, while NMDAR stimulation improves it. Adult rats that explored twice an open field (OF) before a weak though overthreshold training in inhibitory avoidance (IA), expressed IA long-term memory in spite of the hippocampal administration of MK-801, which currently leads to amnesia. Those processes would involve different NMDARs. The selective blockade of hippocampal GluN2B-containing NMDAR with ifenprodil after training promoted memory in an IA task when the training was weak, suggesting that this receptor negatively modulates consolidation. In vivo, after 1h of an OF exposure-with habituation to the environment-, there was an increase in GluN1 and GluN2A subunits in the rat hippocampus, without significant changes in GluN2B. Coincidentally, in vitro, in both rat hippocampal slices and neuron cultures there was an increase in GluN2A-NMDARs surface expression at 30min; an increase in GluN1 and GluN2A levels at about 1h after LTP induction was also shown. We hypothesize that those changes in NMDAR composition could be involved in the "anti-amnesic effect" of the previous OF. Along certain time interval, an increase in GluN1 and GluN2A would lead to an increase in synaptic NMDARs, facilitating synaptic plasticity and memory; while then, an increase in GluN2A/GluN2B ratio could protect the synapse and the already established plasticity, perhaps saving the specific trace.

  9. Information Updating in Working Memory: Its Effect on Teacher Efficacy

    Directory of Open Access Journals (Sweden)

    Jun Tao

    2012-01-01

    Full Text Available Teacher efficacy has a great impact on effective teaching and has been studied in various perspectives. The updating information ability in working memory is always related with many capabilities of cognition. An experiment of N-back task and a questionnaire of teacher efficacy were conducted in this study to test the effect of the ability of information updating in working memory on the teacher efficacy. A significant difference was found in the reaction time between high teacher efficacy group and low teacher efficacy group. The results showed that teachers who scored higher in the teacher efficacy scale tended to react faster than those who scored lower based on the same accuracy. And the updating information ability could serve as a predictor of teacher efficacy.

  10. The role of working memory in the metaphor interference effect.

    Science.gov (United States)

    Pierce, Russell S; Maclaren, Rick; Chiappe, Dan L

    2010-06-01

    Participants took longer to judge that metaphors (e.g., an insult is a razor, memory is a warehouse) were literally false than to judge that scrambled sentences (e.g., an insult is a warehouse) were false. This result is the metaphor interference effect (MIE). It demonstrates that metaphor processing is automatic. In this experiment, we found that the magnitude of the MIE is predicted by working memory (WM) capacity, with higher WM yielding a smaller MIE. This suggests that although metaphor comprehension is automatic, the early processing of metaphors is controllable by executive mechanisms. We relate our results to Kintsch's (2000, 2001) predication model. Specifically, we suggest that mechanisms of WM influence metaphor processing by affecting the effectiveness of the construction-integration process that identifies common properties between topics and vehicles. WM also influences the speed with which meanings are identified as literal or figurative.

  11. Effect of Radiation Exposure on the Retention of Commercial NAND Flash Memory

    Science.gov (United States)

    Oldham, Timothy R.; Chen, D.; Friendlich, M.; Carts, M. A.; Seidleck, C. M.; LaBel, K. A.

    2011-01-01

    We have compared the data retention of irradiated commercial NAND flash memories with that of unirradiated controls. Under some circumstanc es, radiation exposure has a significant effect on the retention of f lash memories.

  12. Programs for the approximation of real and imaginary single- and multi-valued functions by means of Hermite-Padé-approximants

    Science.gov (United States)

    Feil, T. M.; Homeier, H. H. H.

    2004-04-01

    We present programs for the calculation and evaluation of special type Hermite-Padé-approximations. They allow the user to either numerically approximate multi-valued functions represented by a formal series expansion or to compute explicit approximants for them. The approximation scheme is based on Hermite-Padé polynomials and includes both Padé and algebraic approximants as limiting cases. The algorithm for the computation of the Hermite-Padé polynomials is based on a set of recursive equations which were derived from a generalization of continued fractions. The approximations retain their validity even on the cuts of the complex Riemann surface which allows for example the calculation of resonances in quantum mechanical problems. The programs also allow for the construction of multi-series approximations which can be more powerful than most summation methods. Program summaryTitle of program: hp.sr Catalogue identifier: ADSO Program summary URL:http://cpc.cs.qub.ac.uk/summaries/ADSO Program obtainable from: CPC Program Library, Queen's University Belfast, Northern Ireland Licensing provisions: Persons requesting the program must sign the standard CPC non-profit use license Computer: Sun Ultra 10 Installation: Computing Center, University of Regensburg, Germany Operating System: Sun Solaris 7.0 Program language used: MapleV.5 Distribution format: tar gzip file Memory required to execute with typical data: 32 MB; the program itself needs only about 20 kB Number of bits in a word: 32 No. of processors used: 1 Has the code been vectorized?: no No. of bytes in distributed program, including test data etc.: 38194 No. of lines in distributed program, including test data, etc.: 4258 Nature of physical problem: Many physical and chemical quantum systems lead to the problem of evaluating a function for which only a limited series expansion is known. These functions can be numerically approximated by summation methods even if the corresponding series is only asymptotic

  13. Effect of restriction of working memory on reported paranormal belief.

    Science.gov (United States)

    Dudley, R T

    1999-02-01

    56 college students completed Tobacyk's 1988 Revised Paranormal Belief Scale and Watson, Clark, and Tellegen's 1988 Positive and Negative Affect Scale. Experimental group participants, but not control group participants, rehearsed a five-digit number while completing the Paranormal Belief Scale. Analysis showed higher reported paranormal belief for experimental group participants but no differences on the Positive and Negative Affect Scale. Results are discussed in terms of the effect of restriction in working memory on the critical evaluation of paranormal phenomena.

  14. Acoustic emission and shape memory effect in the martensitic transformation.

    Science.gov (United States)

    Sreekala, S; Ananthakrishna, G

    2003-04-01

    Acoustic emission signals are known to exhibit a high degree of reproducibility in time and show correlations with the growth and shrinkage of martensite domains when athermal martensites are subjected to repeated thermal cycling in a restricted temperature range. We show that a recently introduced two dimensional model for the martensitic transformation mimics these features. We also show that these features are related to the shape memory effect where near full reversal of morphological features are seen under these thermal cycling conditions.

  15. Inhomogeneous diffusion and ergodicity breaking induced by global memory effects

    Science.gov (United States)

    Budini, Adrián A.

    2016-11-01

    We introduce a class of discrete random-walk model driven by global memory effects. At any time, the right-left transitions depend on the whole previous history of the walker, being defined by an urnlike memory mechanism. The characteristic function is calculated in an exact way, which allows us to demonstrate that the ensemble of realizations is ballistic. Asymptotically, each realization is equivalent to that of a biased Markovian diffusion process with transition rates that strongly differs from one trajectory to another. Using this "inhomogeneous diffusion" feature, the ergodic properties of the dynamics are analytically studied through the time-averaged moments. Even in the long-time regime, they remain random objects. While their average over realizations recovers the corresponding ensemble averages, departure between time and ensemble averages is explicitly shown through their probability densities. For the density of the second time-averaged moment, an ergodic limit and the limit of infinite lag times do not commutate. All these effects are induced by the memory effects. A generalized Einstein fluctuation-dissipation relation is also obtained for the time-averaged moments.

  16. Afterglow processes responsible for memory effect in nitrogen

    Energy Technology Data Exchange (ETDEWEB)

    Pejovic, M. M. [Faculty of Electronic Engineering, University of Nis, Aleksandra Medvedeva 14, Nis (Serbia); Center of Scientific Research of the Serbian Academy of Sciences and Arts, University of Nis, Univerzitetski trg 2, Nis (Serbia); Nesic, N. T.; Pejovic, M. M.; Zivanovic, E. N. [Faculty of Electronic Engineering, University of Nis, Aleksandra Medvedeva 14, Nis (Serbia)

    2012-07-01

    The mechanisms responsible for memory effect in nitrogen at 6.6 mbars have been analysed based on experimental data of electrical breakdown time delay as a function of afterglow period. The analysis has shown that positive ions remaining from previous discharge, as well as metastable and highly vibrationally excited molecules, are responsible for memory effect in the early afterglow. These molecules lead to the formation of positive ions in mutual collisions in the afterglow. Positive ions initiate secondary electron emission from the cathode of a nitrogen-filled tube when voltage higher than static breakdown voltage is applied on the electrodes. On the other hand, N({sup 4}S) atoms have a large influence on memory effect in late afterglow. They recombine on the cathode surface forming metastable molecules, which release secondary electrons in collision with the cathode. The higher values of electrical breakdown time delay in the case of the tube with borosilicate glass walls than in the case of the tube with copper walls are a consequence of faster de-excitation of neutral active particles on the glass. Indirect confirmation of this assumption has been obtained when the tubes were irradiated with gamma radiation.

  17. Effects of unconscious processing on implicit memory for fearful faces.

    Directory of Open Access Journals (Sweden)

    Jiongjiong Yang

    Full Text Available Emotional stimuli can be processed even when participants perceive them without conscious awareness, but the extent to which unconsciously processed emotional stimuli influence implicit memory after short and long delays is not fully understood. We addressed this issue by measuring a subliminal affective priming effect in Experiment 1 and a long-term priming effect in Experiment 2. In Experiment 1, a flashed fearful or neutral face masked by a scrambled face was presented three times, then a target face (either fearful or neutral was presented and participants were asked to make a fearful/neutral judgment. We found that, relative to a neutral prime face (neutral-fear face, a fearful prime face speeded up participants' reaction to a fearful target (fear-fear face, when they were not aware of the masked prime face. But this response pattern did not apply to the neutral target. In Experiment 2, participants were first presented with a masked faces six times during encoding. Three minutes later, they were asked to make a fearful/neutral judgment for the same face with congruent expression, the same face with incongruent expression or a new face. Participants showed a significant priming effect for the fearful faces but not for the neutral faces, regardless of their awareness of the masked faces during encoding. These results provided evidence that unconsciously processed stimuli could enhance emotional memory after both short and long delays. It indicates that emotion can enhance memory processing whether the stimuli are encoded consciously or unconsciously.

  18. Individual differences in susceptibility to false memories: The effect of memory specificity.

    Science.gov (United States)

    Dewhurst, Stephen A; Anderson, Rachel J; Berry, Donna M; Garner, Sarah R

    2017-06-25

    Previous research has highlighted the wide individual variability in susceptibility to the false memories produced by the Deese/Roediger-McDermott (DRM) procedure [Deese, J. (1959). On the prediction of occurrence of particular verbal intrusions in immediate recall. Journal of Experimental Psychology, 58, 17-22; Roediger, H. L., III, & McDermott, K. B. (1995). Creating false memories: Remembering words not presented in lists. Journal of Experimental Psychology: Learning, Memory, & Cognition, 21, 803-814]. The current study investigated whether susceptibility to false memories is influenced by individual differences in the specificity of autobiographical memory retrieval. Memory specificity was measured using the Sentence Completion for Events from the Past Test (SCEPT) [Raes, F., Hermans, D., Williams, J. M. G., & Eelen, P. (2007). A sentence completion procedure as an alternative to the Autobiographical Memory Test for assessing overgeneral memory in non-clinical populations. Memory, 15, 495-507]. Memory specificity did not correlate with correct recognition, but a specific retrieval style was positively correlated with levels of false recognition. It is proposed that the contextual details that frequently accompany false memories of nonstudied lures are more accessible in individuals with specific retrieval styles.

  19. Memory effects in radiative jet energy loss

    CERN Document Server

    Michler, Frank; Greiner, Carsten

    2009-01-01

    In heavy-ion collisions the created quark-gluon plasma forms a quickly evolving background, leading to a time dependent radiative behavior of high momentum partons traversing the medium. We use the Schwinger Keldysh formalism to describe the jet evolution as a non-equilibrium process including the Landau-Pomeranschuk-Migdal effect. Concentrating on photon emission, a comparison of our results to a quasistatic calculation shows good agreement, leading to the conclusion that the radiative behavior follows the changes in the medium almost instantaneously.

  20. Effects of music on memory for text.

    Science.gov (United States)

    Purnell-Webb, Patricia; Speelman, Craig P

    2008-06-01

    Previous research has suggested that the use of song can facilitate recall of text. This study examined the effect of repetition of a melody across verses, familiarity with the melody, rhythm, and other structural processing hypotheses to explain this phenomenon. Two experiments were conducted, each with 100 participants recruited from undergraduate Psychology programs (44 men, 156 women, M age = 28.5 yr., SD = 9.4). In Exp. 1, participants learned a four-verse ballad in one of five encoding conditions (familiar melody, unfamiliar melody, unknown rhythm, known rhythm, and spoken). Exp. 2 assessed the effect of familiarity in rhythm-only conditions and of pre-exposure with a previously unfamiliar melody. Measures taken were number of verbatim words recalled and number of lines produced with correct syllabic structure. Analysis indicated that rhythm, with or without musical accompaniment, can facilitate recall of text, suggesting that rhythm may provide a schematic frame to which text can be attached. Similarly, familiarity with the rhythm or melody facilitated recall. Findings are discussed in terms of integration and dual-processing theories.

  1. Effects of Childhood Gymnastics Program on Spatial Working Memory.

    Science.gov (United States)

    Hsieh, Shu-Shih; Lin, Chih-Chien; Chang, Yu-Kai; Huang, Chun-Ju; Hung, Tsung-Min

    2017-08-07

    A growing body of evidence has demonstrated the positive effects of physical exercise on cognition in children, and recent studies have specifically investigated the cognitive benefits of exercises involving cognitive-motor interactions, such as gymnastics. This study examined the effect of 8 weeks of gymnastics training on behavioral and neurophysiological measures of spatial working memory in children. Forty-four children aged 7 to 10 yrs were recruited. The experimental group (n = 24; age: 8.7 ± 1.1 yrs) were recruited from Yilan County in Taiwan, while the control group (n = 20; age: 8.6 ± 1.1 yrs) resided in Taipei City. The experimental group undertook 8 weeks of after-school gymnastics training (2 sessions/week, 90 minutes/session), while the control group received no intervention, and were instructed to maintain their routine daily activities. Working memory was assessed by performance on a modified delayed match-to-sample test, and by event-related potential including the P3 component. Data was collected pre and post treatment for the experimental group, and at the same time interval for the control group. Response accuracy improved following the experimental intervention regardless of working memory demands. Likewise, the P3 amplitude was larger at the parietal site after gymnastics training regardless of the task difficulty. Our results suggest that a short period of gymnastics training had a general facilitative effect on spatial working memory at both a behavioral and neurophysiological level in children. These finding highlight the potential importance of exercise programs involving cognitive-motor interactions in stimulating development of spatial cognition during childhood.

  2. Grain Constraint and Size Effects in Shape Memory Alloy Microwires

    Science.gov (United States)

    Ueland, Stian Melhus

    Shape memory alloys exhibit interesting and useful properties, such as the shape memory effect and superelasticity. Among the many alloy families that have been shown to exhibit shape memory properties the ones based on copper are interesting because they are relatively inexpensive and show excellent properties when made as single crystals. However, the performance ofthese alloys is severely compromised by the introduction of grain boundaries, to the point where they are too poor for commercial applications. This thesis studies the mechanical properties of fine Cobased wires with a bamboo microstructure, i.e., where triple junctions are absent and grain boundaries run perpendicular to the wire axis. These microwires are not single crystals, but their microstructure is not as complex as that of polycrystals either: we call this new class of shape memory alloys oligocrystals. This thesis seeks to better understand the relationship between microstructure and properties in these alloys through a combination of mechanical testing, in situ experiments and modeling. First, in situ scanning electron microscopy, together with finite element modeling, is used to understand the role of grain constraint on the martensitic transformation. Grain constraints are observed to be much less severe in oligocrystalline wires as compared to polycrystals. Oligocrystalline microwires are then thermomechanically tested and shown to exhibit excellent properties that approach those of single crystals. Next, property evolution during cycling is investigated, revealing training effects as well as fatigue life and fracture. Finally, size effects in damping and transformation morphology are studied and it is shown that a transition from a many-domain to a single domain martensite morphology takes place when the wire diameter is decreased. (Copies available exclusively from MIT Libraries, libraries.mit.edu/docs - docs@mit.edu)

  3. Supernova energy measurement with longitudinal gravitational memory effect

    CERN Document Server

    Kodwani, Darsh; Yang, I-Sheng

    2016-01-01

    We calculate the gravitational memory effect when a spherically symmetric shell of energy passes through a spacetime region. In particular, this effect includes a longitudinal component, such that two radially separated geodesics pick up a relative velocity proportional to their separation. Such a measurement will allow us to obtain the total energy released by a supernova explosion in the form of neutrinos. We study the possibility to measure such an effect by space-based interferometers such as LISA and BBO, and also by astrophysical interferometers such as pulsar scintillometry.

  4. Effect of chemical component on shape memory effect of Fe-Mn-Si-Ni-C-RE shape memory alloy

    Institute of Scientific and Technical Information of China (English)

    Naichao Si; Zhihong Jia; Longbiao Qi

    2004-01-01

    Effect of chemical component on shape memory effect (SME) of Fe-Mn-Si-Ni-C-RE shape memory alloys was studied by bent measurement, thermal cycle training, SEM etc. Results of study indicate that the alloys with high Mn content (25%) appeare better SME, especially in lower strain. SME improves evidently when Si is higher content, especially it′s range from 3% up to 4%.But brittleness of Fe-Mn-Si-Ni-C-RE alloy increases by increasing the Si content. SME of the alloy is weakening gradually as carbon content increases under small strain (3%). But in the condition of large strain (above 6%), SME of the alloy whose carbon content ranges from 0.1% to 0.12% shows small decreasing range, especially of alloy with the addition of compound RE.

  5. Examining factors involved in stress-related working memory impairments: Independent or conditional effects?

    Science.gov (United States)

    Banks, Jonathan B; Tartar, Jaime L; Tamayo, Brittney A

    2015-12-01

    A large and growing body of research demonstrates the impact of psychological stress on working memory. However, the typical study approach tests the effects of a single biological or psychological factor on changes in working memory. The current study attempted to move beyond the standard single-factor assessment by examining the impact of 2 possible factors in stress-related working memory impairments. To this end, 60 participants completed a working memory task before and after either a psychological stressor writing task or a control writing task and completed measures of both cortisol and mind wandering. We also included a measure of state anxiety to examine the direct and indirect effect on working memory. We found that mind wandering mediated the relationship between state anxiety and working memory at the baseline measurement. This indirect relationship was moderated by cortisol, such that the impact of mind wandering on working memory increased as cortisol levels increased. No overall working memory impairment was observed following the stress manipulation, but increases in state anxiety and mind wandering were observed. State anxiety and mind wandering independently mediated the relationship between change in working memory and threat perception. The indirect paths resulted in opposing effects on working memory. Combined, the findings from this study suggest that cortisol enhances the impact of mind wandering on working memory, that state anxiety may not always result in stress-related working memory impairments, and that high working memory performance can protect against mind wandering.

  6. Sex differences in stress effects on response and spatial memory formation.

    Science.gov (United States)

    Guenzel, Friederike M; Wolf, Oliver T; Schwabe, Lars

    2014-03-01

    Stress and stress hormones are known to affect learning and memory processes. However, although effects of stress on hippocampus-dependent declarative learning and memory are well-documented, relatively little attention has been paid to the impact of stress on striatum-dependent stimulus-response (S-R) learning and memory. Recent evidence indicates that glucocorticoid stress hormones shortly after learning enhance S-R memory consolidation, whereas stress prior to retention testing impairs S-R memory retrieval. Whether stress affects also the acquisition of S-R memories in humans remains unclear. For this reason, we examined here the effects of acute stress on S-R memory formation and contrasted these stress effects with those on hippocampus-dependent spatial memory. Healthy men and women underwent a stressor (socially evaluated cold pressor test, SECPT) or a control manipulation before they completed an S-R task and two spatial learning tasks. Memory was assessed one week later. Our data showed that stress impaired S-R memory performance in men but not in women. Conversely, spatial memory was impaired by stress in women but not in men. These findings provide further evidence that stress may alter learning and memory processes beyond the hippocampus. Moreover, our data underline that participants' sex may play a critical role in the impact of stress on multiple memory systems.

  7. Memory for incidentally perceived social cues: Effects on person judgment.

    Science.gov (United States)

    Pawling, Ralph; Kirkham, Alexander J; Tipper, Steven P; Over, Harriet

    2017-02-01

    Dynamic face cues can be very salient, as when observing sudden shifts of gaze to a new location, or a change of expression from happy to angry. These highly salient social cues influence judgments of another person during the course of an interaction. However, other dynamic cues, such as pupil dilation, are much more subtle, affecting judgments of another person even without awareness. We asked whether such subtle, incidentally perceived, dynamic cues could be encoded in to memory and retrieved at a later time. The current study demonstrates that in some circumstances changes in pupil size in another person are indeed encoded into memory and influence judgments of that individual at a later time. Furthermore, these judgments interact with the perceived trustworthiness of the individual and the nature of the social context. The effect is somewhat variable, however, possibly reflecting individual differences and the inherent ambiguity of pupil dilation/constriction. © 2016 The British Psychological Society.

  8. Randomness Effect on Cooperation in Memory-Based Snowdrift Game

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ming-Feng; WANG Bing-Hong; WANG Wen-Xu; TANG Chuan-Long; YANG Rui

    2008-01-01

    @@ A memory-based snowdrift game (MBSG) on spatial small-world networks is investigated. It is found that cooperation rate versus temptation shows some step structures on small-world networks, similar to the case on regular latticcs. With the increment of rewiring probability based on four-neighbour regular lattices, more steps are observable. Interestingly, it is observed that cooperation rate peaks at a specific value of temptation,which indicates that properly encouraging selfish actions may lead to better cooperative behaviours in the MBSG on small-world networks. Memory effects are also discussed for different rewiring probabilities. Furthermore,optimal regions are found in the parameter planes. The strategy-related average degrees of individuals are helpful to understand the obtained results.

  9. Shape-memory effect in Co-Ni single crystal

    Institute of Scientific and Technical Information of China (English)

    周伟敏; 刘岩; 张少宗; 江伯鸿

    2004-01-01

    The thermal shape-memory effect at room temperature for Co-32% Ni(mass fraction) magnetic shape memory alloy of single crystal was presented. When compressing the sample along the [001] direction at room temperature, strain can be recovered to some extent during later heating and the recovery rate varies with the pre-strain.But no obvious recoverable strain can be obtained along other crystal directions. For the thermal-mechanical training of the sample along [001], the recovery strain decreases obviously during the second round of compress and nearly no recovery happens after the third round of compress. A possible mechanism based on reversible motions of Shockley partial dislocations was proposed.

  10. Weak ergodicity breaking induced by global memory effects

    Science.gov (United States)

    Budini, Adrián A.

    2016-08-01

    We study the phenomenon of weak ergodicity breaking for a class of globally correlated random walk dynamics defined over a finite set of states. The persistence in a given state or the transition to another one depends on the whole previous temporal history of the system. A set of waiting time distributions, associated to each state, sets the random times between consecutive steps. Their mean value is finite for all states. The probability density of time-averaged observables is obtained for different memory mechanisms. This statistical object explicitly shows departures between time and ensemble averages. While the residence time in each state may have a divergent mean value, we demonstrate that this condition is in general not necessary for breaking ergodicity. Hence, we conclude that global memory effects are an alternative mechanism able to induce ergodicity breaking without involving power-law statistics. Analytical and numerical calculations support these results.

  11. Measurements of radiation effects on a 4 Mb PSRAM memory

    Science.gov (United States)

    Gonçalez, Odair Lelis; Pereira Junior, Evaldo Carlos Fonseca; Vaz, Rafael Galhardo; Pereira, Marlon Antonio; Wirth, Gilson Inácio; Both, Thiago Hanna

    2014-11-01

    The results of a static test of total ionizing dose (TID) effects on an ISSI 4Mb PSRAM memory are reported in this work. The irradiation was performed at the IEAv's Laboratory of Ionizing Radiation with 1.17 and 1.32 MeV gamma-rays from a 60Co source at a dose rate of 2.5 krad/h up to an accumulated dose of 215.7 krad. The TID threshold for bit flip found in this experiment was 52.5 krad. From a sampling of 4096 memory addresses it was estimated a bit flip rate of approximately 50% at an accumulated dose of 215.7 krad.

  12. Effects of melody and lyrics on mood and memory.

    Science.gov (United States)

    Sousou, S D

    1997-08-01

    137 undergraduate Le Moyne College students volunteered in a study on music and its effects on mood and memory. In a 2 x 3 between-subjects design, there were 2 lyric conditions (Happy and Sad Lyrics) and 3 music conditions (No Music, Happy Music, and Sad Music). Participants were asked to listen to instrumental music or mentally to create a melody as they read lyrics to themselves. The study tested cued-recall, self-reported mood state and psychological arousal. Analysis suggested that mood of participants was influenced by the music played, not the lyrics. Results also showed those exposed to No Music had the highest score on the recall test. Personal relevance to the lyrics was not correlated with memory.

  13. Thermoelectric Effects in Simulations of Phase Change Memory Mushroom Cells

    Science.gov (United States)

    Faraclas, Azer; Bakan, Gokhan; Gokirmak, Ali; Silva, Helena

    2012-02-01

    Phase change memory is a potential candidate for the future of high-speed non-volatile memory, however significant improvements in cell design is crucial for its success in the mainstream market. Due to the asymmetric geometry of phase change mushroom cells and the high temperature gradients generated, thermoelectric effects play a key role in determining energy consumption, cell performance, and reliability. In this study, rotationally symmetric 2D finite element simulations using COMSOL Multiphysics are implemented for GeSbTe (GST). Temperature dependent material parameters (electrical conductivity, thermal conductivity, heat capacity, and Seebeck coefficient) are included in the model for accuracy. Switching the direction of current shows a large change in peak molten volume within the cell, as well as current and power consumption.

  14. A Spatial-Context Effect in Recognition Memory

    Directory of Open Access Journals (Sweden)

    Daniel Pacheco

    2017-08-01

    Full Text Available We designed a novel experiment to investigate the modulation of human recognition memory by environmental context. Human participants were asked to navigate through a four-arm Virtual Reality (VR maze in order to find and memorize discrete items presented at specific locations in the environment. They were later on tested on their ability to recognize items as previously presented or new. By manipulating the spatial position of half of the studied items during the testing phase of our experiment, we could assess differences in performance related to the congruency of environmental information at encoding and retrieval. Our results revealed that spatial context had a significant effect on the quality of memory. In particular, we found that recognition performance was significantly better in trials in which contextual information was congruent as opposed to those in which it was different. Our results are in line with previous studies that have reported spatial-context effects in recognition memory, further characterizing their magnitude under ecologically valid experimental conditions.

  15. Inconvenient magnetocaloric effect in ferromagnetic shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Khovaylo, Vladimir, E-mail: khovaylo@misis.ru [National University of Science and Technology “MISiS”, Moscow 119049 (Russian Federation)

    2013-11-15

    Highlights: ► Critical analysis of the available experimental results on isothermal magnetic entropy change in ferromagnetic shape memory alloys Ni–Mn–X (X = Ga, In, Sn, Sb) is given. ► Based on available in literature experimental data on total entropy change at martensitic transformation it is shown that the isothermal magnetic entropy change in Ni–Mn–X (X = Ga, In, Sn, Sb) should not greatly exceed 30 J/kg K. -- Abstract: Critical analysis available in the literature experimental results on magnetocaloric effect in ferromagnetic shape memory alloys Ni–Mn–X (X = Ga, In, Sn, Sb) is given. Based on a model developed by Pecharsky et al. [22], it is shown that the isothermal magnetic field-induced entropy change in the Ni–Mn–X alloys should not greatly exceed 30 J/kg K. Considering thermodynamics of temperature- and magnetic field-induced martensitic transformations, it is demonstrated that a contribution of the structural subsystem to the magnetocaloric effect in the Ni–Mn–X alloys studied so far is irreversible in magnetic fields below 5 T. This makes ferromagnetic shape memory alloys an inconvenient system for the practical application in modern magnetic refrigeration technology.

  16. Decrease-radix design principle for carrying/borrowing free multi-valued and application in ternary optical computer

    Institute of Scientific and Technical Information of China (English)

    YAN JunYong; JIN Yi; ZUO KaiZhong

    2008-01-01

    In this paper a new theory referred to as the decrease-radix design (DRD) is proposed,which is found in the research of logic units of ternary (tri-valued) optical computer.Based on the theory proposed,the principles and the regulations of the DRD for making operation units of multi-valued operation with carrying/borrowing free are also presented.The research work has come to the following important conclusion:let D be a special state contained in n physical informative states,then one may figure out any multi-valued processors within n(n×n) carrying/borrowing free n-valued units by the composition some of n×n×(n-1) simplest basic operating units according to the regulations of DRD proposed in this paper.The detailed systematic way of our design regulations is highlighted step by step in the paper with an example of design of a tri-valued logic optical operating unit.The real architecture,the procedure,and the experimental results of our sample in tri-valued logic operating unit are given.Finally,a re-constructible model of ternary logical optical processor is introduced.The theory proposed in the paper has laid down a solid foundation for the design of re-constructible carrying/borrowing free operating units in ternary optical computers and can be widely used as the designing reference in a variety of multi-valued logic operating units.

  17. [Effects of recollecting autobiographical memories on the emotional well-being of older adults].

    Science.gov (United States)

    Westerhof, G J; Lamers, S M A; de Vries, D R S L

    2010-02-01

    This experiment examined the effect of different ways of recollecting autobiographical memories on emotional well-being. Participants between 65 and 80 years old (N = 70) were instructed to write about a memory from their life when they were 15 to 30 years old. They were asked to do this in a narrative way about a positive memory, in a narrative way about a negative memory or in an interpretative way about a negative memory. We also examined whether spontaneous reminiscence types in everyday life moderate the effects of the experimental manipulation on emotional well-being. Narrating positive memories is more favourable for negative affect than narrating or interpreting negative memories. There is no moderating role for everyday reminiscence types, even though these are related to emotional well-being. Manipulated and spontaneous reminiscence are therefore different. This is a favourable finding for reminiscence interventions, because they can stimulate positive memories, no matter how older people are used to memorize their past.

  18. Near- and far-transfer effects of working memory updating training in elderly adults

    NARCIS (Netherlands)

    Xin, Z.; Lai, Z.R.; Fu, L.; Maes, J.H.R.

    2014-01-01

    Age-related declines in working memory, especially with regard to updating ability, affect many high-level aspects of cognition in elderly adults. Recent studies have demonstrated that training might improve working memory. We investigated the effects of 20days of adaptive training of working memory

  19. Computer Use and Its Effect on the Memory Process in Young and Adults

    Science.gov (United States)

    Alliprandini, Paula Mariza Zedu; Straub, Sandra Luzia Wrobel; Brugnera, Elisangela; de Oliveira, Tânia Pitombo; Souza, Isabela Augusta Andrade

    2013-01-01

    This work investigates the effect of computer use in the memory process in young and adults under the Perceptual and Memory experimental conditions. The memory condition involved the phases acquisition of information and recovery, on time intervals (2 min, 24 hours and 1 week) on situations of pre and post-test (before and after the participants…

  20. Opposite Effects of Cortisol on Consolidation of Temporal Sequence Memory during Waking and Sleep

    Science.gov (United States)

    Wilhelm, Ines; Wagner, Ullrich; Born, Jan

    2011-01-01

    Memory functions involve three stages: encoding, consolidation, and retrieval. Modulating effects of glucocorticoids (GCs) have been consistently observed for declarative memory with GCs enhancing encoding and impairing retrieval, but surprisingly, little is known on how GCs affect memory consolidation. Studies in rats suggest a beneficial effect…

  1. Effects of Anxiety on Memory Storage and Updating in Young Children

    Science.gov (United States)

    Visu-Petra, Laura; Cheie, Lavinia; Benga, Oana; Alloway, Tracy Packiam

    2011-01-01

    The relationship between trait anxiety and memory functioning in young children was investigated. Two studies were conducted, using tasks tapping verbal and visual-spatial short-term memory (Study 1) and working memory (Study 2) in preschoolers. On the verbal storage tasks, there was a detrimental effect of anxiety on processing efficiency…

  2. Opposite Effects of Cortisol on Consolidation of Temporal Sequence Memory during Waking and Sleep

    Science.gov (United States)

    Wilhelm, Ines; Wagner, Ullrich; Born, Jan

    2011-01-01

    Memory functions involve three stages: encoding, consolidation, and retrieval. Modulating effects of glucocorticoids (GCs) have been consistently observed for declarative memory with GCs enhancing encoding and impairing retrieval, but surprisingly, little is known on how GCs affect memory consolidation. Studies in rats suggest a beneficial effect…

  3. Working Memory Capacity and Reading Skill Moderate the Effectiveness of Strategy Training in Learning from Hypertext

    Science.gov (United States)

    Naumann, Johannes; Richter, Tobias; Christmann, Ursula; Groeben, Norbert

    2008-01-01

    Cognitive and metacognitive strategies are particularly important for learning with hypertext. The effectiveness of strategy training, however, depends on available working memory resources. Thus, especially learners high on working memory capacity can profit from strategy training, while learners low on working memory capacity might easily be…

  4. Mood-congruent true and false memory: effects of depression.

    Science.gov (United States)

    Howe, Mark L; Malone, Catherine

    2011-02-01

    The Deese/Roediger-McDermott paradigm was used to investigate the effect of depression on true and false recognition. In this experiment true and false recognition was examined across positive, neutral, negative, and depression-relevant lists for individuals with and without a diagnosis of major depressive disorder. Results showed that participants with major depressive disorder falsely recognised significantly more depression-relevant words than non-depressed controls. These findings also parallel recent research using recall instead of recognition and show that there are clear mood congruence effects for depression on false memory performance.

  5. Memory effects in nonadiabatic molecular dynamics at metal surfaces

    DEFF Research Database (Denmark)

    Olsen, Thomas; Schiøtz, Jakob

    2010-01-01

    We study the effect of temporal correlation in a Langevin equation describing nonadiabatic dynamics at metal surfaces. For a harmonic oscillator, the Langevin equation preserves the quantum dynamics exactly and it is demonstrated that memory effects are needed in order to conserve the ground state...... energy of the oscillator. We then compare the result of Langevin dynamics in a harmonic potential with a perturbative master equation approach and show that the Langevin equation gives a better description in the nonperturbative range of high temperatures and large friction. Unlike the master equation...... the temporal correlation function and dynamical friction within density functional theory....

  6. The effects of nicotine on intrusive memories in nonsmokers.

    Science.gov (United States)

    Hawkins, Kirsten A; Cougle, Jesse R

    2013-12-01

    Correlational research suggests that smoking increases risk of posttraumatic stress disorder (PTSD), though such research by nature cannot rule out third variable explanations for this relationship. The present study used an analogue trauma film design to experimentally test the effects of nicotine on the occurrence of intrusive memories. Fifty-four healthy nonsmokers were randomly assigned to ingest either a nicotine or placebo lozenge before viewing a film depicting motor vehicle accidents. Participants recorded intrusive memories immediately after the film and for a week via diary. Participants in the nicotine condition reported significantly more intrusive memories immediately after watching the film, yet no group differences emerged on intrusions or intrusion-related distress reported during the following week. Among participants low in dispositional rumination, those who had ingested a nicotine lozenge reported more intrusions in the subsequent week than those in the placebo condition. These findings provide novel experimental evidence for the role of nicotine in increasing risk of PTSD and suggest that nicotine may contribute to trauma-related rumination but not heightened reactivity to trauma cues.

  7. Effects of attractiveness on face memory separated from distinctiveness: evidence from event-related brain potentials.

    Science.gov (United States)

    Wiese, Holger; Altmann, Carolin S; Schweinberger, Stefan R

    2014-04-01

    The present study examined effects of attractiveness on behavioral and event-related potential (ERP) correlates of face memory. Extending previous reports, we controlled for potential moderating effects of distinctiveness, a variable known to affect memory. Attractive and unattractive faces were selected on the basis of a rating study, and were matched for distinctiveness. In a subsequent recognition memory experiment, we found more accurate memory for unattractive relative to attractive faces. Additionally, an attractiveness effect in the early posterior negativity (EPN) during learning, with larger amplitudes for attractive than unattractive faces, correlated significantly with the magnitude of the memory advantage for unattractive faces at test. These findings establish a contribution of attractiveness to face memory over and above the well-known effect of distinctiveness. Additionally, as the EPN is typically enhanced for affective stimuli, our ERP results imply that the processing of emotionally relevant attractive faces during learning may hamper their encoding into memory. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. The effect of dehydroepiandrosterone (DHEA) on recognition memory decision processes and discrimination in postmenopausal women.

    Science.gov (United States)

    Hirshman, Elliot; Wells, Ellen; Wierman, Margaret E; Anderson, Benjamin; Butler, Andrew; Senholzi, Meredith; Fisher, Julia

    2003-03-01

    In this article, the theoretical distinction between recognition memory decision and discrimination processes is used to explore the effect of dehydroepiandrosterone (DHEA) in postmenopausal women. DHEA is an adrenal steroid that diminishes with aging. It has enhanced memory in laboratory animals. An 8-week placebo-controlled, double-blind experiment in which 30 women (ages 39-70) received a 50-mg/day oral dose of DHEA for 4 weeks demonstrated that DHEA made subjects more conservative (i.e., less likely to call test items "old") in their recognition memory decisions and enhanced recognition memory discrimination for items presented briefly. The former result may reflect an empirical regularity (Hirshman, 1995) in which recent strong memory experiences make participants more conservative. The latter result may reflect the effect of DHEA on visual perception, with consequent effects on memory. These results suggest the methodological importance of focusing on decision processes when examining the effects of hormones on memory.

  9. Hippocampal activity is associated with self-descriptiveness effect in memory, whereas self-reference effect in memory depends on medial prefrontal activity.

    Science.gov (United States)

    Zhu, Lei; Guo, Xiuyan; Li, Jianqi; Zheng, Li; Wang, Qianfeng; Yang, Zhiliang

    2012-07-01

    The self has long been regarded as a unique cognitive structure by virtue of its superior mnemonic abilities. Two separate effects result from this self memory facilitation: self-reference effect and self-descriptiveness effect in memory. Self-reference effect denotes that information processed with reference to the self is better remembered than information processed with reference to others, whereas self-descriptiveness effect indicates that items judged to be self-relevant is remembered better than items judged not to be relevant to self during self-reference task. Although there is a compelling connection between self-reference effect in memory and self mentalization processes indexed by the medial prefrontal activity, the underlying mechanisms of the self-descriptiveness effect in memory have remained underspecified. In the present fMRI study, we used a subsequent memory paradigm to examine the neural correlates of self-descriptiveness and self-reference effect in memory. Participants encoded personality traits while performing self-reference and other-reference task (judged the descriptiveness of the traits to themselves or a famous person "Bruce Lee"), and then were given a test of recognition memory outside the scanner. It is revealed that the hippocampal activity corresponded with self-descriptiveness effect in memory, but the activity of the medial prefrontal cortex and perirhinal cortex related to self-reference effect in memory. These findings suggested that the memory boost for self-relevant items relies on the enhanced relational binding mechanisms employed during self-relevant items.

  10. Synesthesia and Memory: Color Congruency, Von Restorff, and False Memory Effects

    Science.gov (United States)

    Radvansky, Gabriel A.; Gibson, Bradley S.; McNerney, M. Windy

    2011-01-01

    In the current study, we explored the influence of synesthesia on memory for word lists. We tested 10 grapheme-color synesthetes who reported an experience of color when reading letters or words. We replicated a previous finding that memory is compromised when synesthetic color is incongruent with perceptual color. Beyond this, we found that,…

  11. Effects of a Memory Training Program in Older People with Severe Memory Loss

    Science.gov (United States)

    Mateos, Pedro M.; Valentin, Alberto; González-Tablas, Maria del Mar; Espadas, Verónica; Vera, Juan L.; Jorge, Inmaculada García

    2016-01-01

    Strategies based memory training programs are widely used to enhance the cognitive abilities of the elderly. Participants in these training programs are usually people whose mental abilities remain intact. Occasionally, people with cognitive impairment also participate. The aim of this study was to test if memory training designed specifically for…

  12. Synesthesia and Memory: Color Congruency, Von Restorff, and False Memory Effects

    Science.gov (United States)

    Radvansky, Gabriel A.; Gibson, Bradley S.; McNerney, M. Windy

    2011-01-01

    In the current study, we explored the influence of synesthesia on memory for word lists. We tested 10 grapheme-color synesthetes who reported an experience of color when reading letters or words. We replicated a previous finding that memory is compromised when synesthetic color is incongruent with perceptual color. Beyond this, we found that,…

  13. Memory load effect in auditory-verbal short-term memory task: EEG fractal and spectral analysis.

    Science.gov (United States)

    Stokić, Miodrag; Milovanović, Dragan; Ljubisavljević, Miloš R; Nenadović, Vanja; Čukić, Milena

    2015-10-01

    The objective of this preliminary study was to quantify changes in complexity of EEG using fractal dimension (FD) alongside linear methods of spectral power, event-related spectral perturbations, coherence, and source localization of EEG generators for theta (4-7 Hz), alpha (8-12 Hz), and beta (13-23 Hz) frequency bands due to a memory load effect in an auditory-verbal short-term memory (AVSTM) task for words. We examined 20 healthy individuals using the Sternberg's paradigm with increasing memory load (three, five, and seven words). The stimuli were four-letter words. Artifact-free 5-s EEG segments during retention period were analyzed. The most significant finding was the increase in FD with the increase in memory load in temporal regions T3 and T4, and in parietal region Pz, while decrease in FD with increase in memory load was registered in frontal midline region Fz. Results point to increase in frontal midline (Fz) theta spectral power, decrease in alpha spectral power in parietal region-Pz, and increase in beta spectral power in T3 and T4 region with increase in memory load. Decrease in theta coherence within right hemisphere due to memory load was obtained. Alpha coherence increased in posterior regions with anterior decrease. Beta coherence increased in fronto-temporal regions. Source localization delineated theta activity increase in frontal midline region, alpha decrease in superior parietal region, and beta increase in superior temporal gyrus with increase in memory load. In conclusion, FD as a nonlinear measure may serve as a sensitive index for quantifying dynamical changes in EEG signals during AVSTM tasks.

  14. Effects of endocannabinoid and endovanilloid systems on aversive memory extinction.

    Science.gov (United States)

    Laricchiuta, Daniela; Centonze, Diego; Petrosini, Laura

    2013-11-01

    In contextual fear conditioning animals have to integrate various elemental stimuli into a coherent representation of the condition and then associate context representation with punishment. Although several studies indicated the modulating role of endocannabinoid system (ECS) on the associative learning, ECS effect on contextual fear conditioning requires further investigations. The present study assessed the effects of the increased endocannabinoid anandamide (AEA) tone on acquisition, retrieval and extinction of the contextual fear conditioning. Given that AEA may bind to cannabinoid type 1 (CB1) receptors as well as to postsynaptic ionotropic Transient Receptor Potential Vanilloid type 1 (TRPV1) channels, particular attention was paid in determining how the increased AEA tone influenced fear responses. Furthermore, it was investigated how the ECS modulated the effects of stress-sensitization on fear response. Thus, mice submitted or not to a social defeat stress protocol were treated with drugs acting on ECS, CB1 receptors or TRPV1 channels and tested in a contextual fear conditioning whose conditioning, retrieval and extinction phases were analyzed. ECS activation influenced the extinction process and contrasted the stress effects on fear memory. Furthermore, CB1 receptor antagonist blocked and TRPV1 channel antagonist promoted short- and long-term extinction. The present study indicates that ECS controls the extinction of aversive memories in the contextual fear conditioning.

  15. Cortisol mediates the effects of stress on the contextual dependency of memories.

    Science.gov (United States)

    van Ast, Vanessa A; Cornelisse, Sandra; Meeter, Martijn; Kindt, Merel

    2014-03-01

    Stress is known to exert considerable impact on learning and memory processes. Typically, human studies have investigated memory for single items (e.g., pictures, words), but it remains unresolved how exactly stress may alter the storage of memories into their original encoding context (i.e., memory contextualization). Since neurocircuitry underlying memory contextualization processes is sensitive to the well-known stress hormone cortisol, we here investigated whether cortisol mediates stress effects on memory contextualization. Forty healthy young men were randomly assigned to a psychosocial stress or control group. Ten minutes after stress manipulation offset, participants were instructed to learn and remember neutral and negative words, each of which was depicted against a unique background picture. Approximately 24h later, memory was tested by means of cued retrieval and recognition tasks. To assess memory contextualization half of the words were tested in intact item-contexts pairs, and half in rearranged item-context combinations. Recognition data showed that cortisol, but no other indices of stress such as heart rate or subjective stress, mediated the effects of stress on contextualization of neutral and negative memories. The mediation analysis further showed that stress resulted in increases in cortisol and that cortisol was positively related to memory contextualization, but unrelated to other measures of memory. Thus, there seems to be a specific role for cortisol in the integration of a central memory into its surrounding context.

  16. Delayed emergence of effects of memory-enhancing drugs: implications for the dynamics of long-term memory.

    Science.gov (United States)

    Mondadori, C; Hengerer, B; Ducret, T; Borkowski, J

    1994-01-01

    Many theories of memory postulate that processing of information outlasts the learning situation and involves several different physiological substrates. If such physiologically distinct mechanisms or stages of memory do in fact exist, they should be differentially affected by particular experimental manipulations. Accordingly, a selective improvement of the processes underlying short-term memory should be detectable only while the information is encoded in the short-term mode, and a selective influence on long-term memory should be detectable only from the moment when memory is based on the long-term trace. Our comparative study of the time course of the effects of the cholinergic agonist arecoline, the gamma-aminobutyric acid type B receptor antagonist CGP 36742, the angiotensin-converting enzyme inhibitor captopril, and the nootropic oxiracetam, four substances with completely different primary sites of action, show that the memory-enhancing effects consistently come into evidence no sooner than 16-24 h after the learning trial. On the one hand, this finding suggests that all these substances act by way of the same type of mechanism; on the other hand, it demonstrates that the substrate modulated by the compounds forms the basis of memory only after 16-24 h. From the observation that animals also show clear signs of retention during the first 16 h--i.e., before the effects of the substances are measurable--it can be inferred that retention during this time is mediated by other mechanisms that are not influenced by any of the substances. Images PMID:8134347

  17. Visuospatial and verbal working memory load: effects on visuospatial vigilance.

    Science.gov (United States)

    Helton, William S; Russell, Paul N

    2013-02-01

    In this study, we examined the impact of concurrent verbal and visuospatial working memory demands on performance of a visuospatial successive target detection task. Three hundred and four participants performed a visuospatial vigilance task while simultaneously performing either a spatial or verbal working memory task that either required a memory load during the vigil or did not require a memory load during the vigil. Perceptual sensitivity A' to vigilance target stimuli was reduced by concurrent memory load, both verbal and visuospatial. The decline in perceptual sensitivity to vigilance targets, the vigilance decrement, was steeper for a visuospatial memory task than a verbal memory task, regardless of concurrent memory load. Memory performance after vigilance detection trials was much lower for visuospatial than verbal items, even though memory performance before vigilance detection trials was higher for visuospatial than verbal items. Together, this indicates increased interference when a visuospatial vigilance task is paired with a visuospatial memory task, than when paired with a verbal memory task. Overall, the visuospatial and verbal working memory loads both impacted vigilance target detection, suggesting utilization of common executive resources. There may, however, be domain specific interference, and this may be exacerbated for two visuospatial tasks.

  18. Memory effects in stock price dynamics: evidences of technical trading

    Science.gov (United States)

    Garzarelli, Federico; Cristelli, Matthieu; Pompa, Gabriele; Zaccaria, Andrea; Pietronero, Luciano

    2014-03-01

    Technical trading represents a class of investment strategies for Financial Markets based on the analysis of trends and recurrent patterns in price time series. According standard economical theories these strategies should not be used because they cannot be profitable. On the contrary, it is well-known that technical traders exist and operate on different time scales. In this paper we investigate if technical trading produces detectable signals in price time series and if some kind of memory effects are introduced in the price dynamics. In particular, we focus on a specific figure called supports and resistances. We first develop a criterion to detect the potential values of supports and resistances. Then we show that memory effects in the price dynamics are associated to these selected values. In fact we show that prices more likely re-bounce than cross these values. Such an effect is a quantitative evidence of the so-called self-fulfilling prophecy, that is the self-reinforcement of agents' belief and sentiment about future stock prices' behavior.

  19. Memory effects in stock price dynamics: evidences of technical trading

    Science.gov (United States)

    Garzarelli, Federico; Cristelli, Matthieu; Pompa, Gabriele; Zaccaria, Andrea; Pietronero, Luciano

    2014-01-01

    Technical trading represents a class of investment strategies for Financial Markets based on the analysis of trends and recurrent patterns in price time series. According standard economical theories these strategies should not be used because they cannot be profitable. On the contrary, it is well-known that technical traders exist and operate on different time scales. In this paper we investigate if technical trading produces detectable signals in price time series and if some kind of memory effects are introduced in the price dynamics. In particular, we focus on a specific figure called supports and resistances. We first develop a criterion to detect the potential values of supports and resistances. Then we show that memory effects in the price dynamics are associated to these selected values. In fact we show that prices more likely re-bounce than cross these values. Such an effect is a quantitative evidence of the so-called self-fulfilling prophecy, that is the self-reinforcement of agents' belief and sentiment about future stock prices' behavior. PMID:24671011

  20. Memory effects in stock price dynamics: evidences of technical trading.

    Science.gov (United States)

    Garzarelli, Federico; Cristelli, Matthieu; Pompa, Gabriele; Zaccaria, Andrea; Pietronero, Luciano

    2014-03-27

    Technical trading represents a class of investment strategies for Financial Markets based on the analysis of trends and recurrent patterns in price time series. According standard economical theories these strategies should not be used because they cannot be profitable. On the contrary, it is well-known that technical traders exist and operate on different time scales. In this paper we investigate if technical trading produces detectable signals in price time series and if some kind of memory effects are introduced in the price dynamics. In particular, we focus on a specific figure called supports and resistances. We first develop a criterion to detect the potential values of supports and resistances. Then we show that memory effects in the price dynamics are associated to these selected values. In fact we show that prices more likely re-bounce than cross these values. Such an effect is a quantitative evidence of the so-called self-fulfilling prophecy, that is the self-reinforcement of agents' belief and sentiment about future stock prices' behavior.

  1. Issues in chaos synchronization: Subharmonic destruction, multi-valued mappings, and chaotic lightwave communication

    Science.gov (United States)

    Lewis, Clifford Tureman

    A wide range of issues concerning the theory and practice of generalized synchronization of chaos are examined in detail. Due in part to the straightforward geometrical interpretation of identical synchronization, the corresponding theory has been firmly established. However, generalized synchronization, which corresponds to the formation of a continuous mapping between non- identical sub-systems, still possesses many facets which have not been examined in depth. Thus, a comprehensive theory of generalized synchronization is still being constructed. In this dissertation, studies concerning several scarcely examined aspects of generalized synchronization are presented. First, a mechanism is examined by which synchronization is lost in non-identical systems with different fundamental frequencies of oscillation. This mechanism, which is the subharmonic transition, is fundamentally different than previously examined mechanisms that are commonly cited in synchronization studies. Second, an examination of the properties of the generalized synchronization mapping when it is no longer a one-to-one mapping is presented. Most previously studied characteristics of generalized synchronization concern synchronization mappings which are one-to-one and invertible. The study in this dissertation shows interesting structure when the mapping is multi-valued, and thus is not invertible. The final portion of this dissertation concerns chaotic lightwave communication, a practical application of synchronization using erbium-doped fiber ring lasers to optically transmit a modulated bit string across a fiber optic channel using the chaotic laser intensity waveform as the carrier. Development of a successful communications scheme is a five-fold task. First, an empirical model of an erbium-doped fiber ring laser, which includes all the physically relevant variables, is derived from first principles. Next, the amount of chaos present in the laser model must be quantified. Subsequently, the

  2. The effects of eye movements on emotional memories: using an objective measure of cognitive load

    Directory of Open Access Journals (Sweden)

    Suzanne C. van Veen

    2016-07-01

    Full Text Available Background: Eye movement desensitization and reprocessing (EMDR is an effective treatment for posttraumatic stress disorder. The working memory (WM theory explains its efficacy: recall of an aversive memory and making eye movements (EM both produce cognitive load, and competition for the limited WM resources reduces the memory's vividness and emotionality. The present study tested several predictions from WM theory. Objective: We hypothesized that 1 recall of an aversive autobiographical memory loads WM compared to no recall, and 2 recall with EM reduces the vividness, emotionality, and cognitive load of recalling the memory more than only recall or only cognitive effort (i.e., recall of an irrelevant memory with EM. Method: Undergraduates (N=108 were randomly assigned to one of three conditions: 1 recall relevant memory with EM, 2 recall relevant memory without EM, and 3 recall irrelevant memory with EM. We used a random interval repetition task to measure the cognitive load of recalling the memory. Participants responded to randomly administered beeps, with or without recalling the memory. The degree to which participants slow down during recall provides an index of cognitive load. We measured the cognitive load and self-reported vividness and emotionality before, halfway through (8×24 s, and after (16×24 s the intervention. Results: Reaction times slowed down during memory recall compared to no recall. The recall relevant with EM condition showed a larger decrease in self-reported vividness and emotionality than the control conditions. The cognitive load of recalling the memory also decreased in this condition but not consistently more than in the control conditions. Conclusions: Recall of an aversive memory loads WM, but drops in vividness and emotionality do not immediately reduce the cognitive load of recalling the memory. More research is needed to find objective measures that could capture changes in the quality of the memory.

  3. Effects of sleep on memory for conditioned fear and fear extinction

    Science.gov (United States)

    Pace-Schott, Edward F.; Germain, Anne; Milad, Mohammed R.

    2015-01-01

    Learning and memory for extinction of conditioned fear is a basic mammalian mechanism for regulating negative emotion. Sleep promotes both the consolidation of memory and the regulation of emotion. Sleep can influence consolidation and modification of memories associated with both fear and its extinction. After brief overviews of the behavior and neural circuitry associated with fear conditioning, extinction learning and extinction memory in the rodent and human, interactions of sleep with these processes will be examined. Animal and human studies suggest that sleep can serve to consolidate both fear and extinction memory. In humans, sleep also promotes generalization of extinction memory. Time-of-day effects on extinction learning and generalization are also seen. REM may be a sleep stage of particular importance for the consolidation of both fear and extinction memory as evidenced by selective REM deprivation experiments. REM sleep is accompanied by selective activation of the same limbic structures implicated in the learning and memory of fear and extinction. Preliminary evidence also suggests extinction learning can take place during slow wave sleep. Study of low-level processes such as conditioning, extinction and habituation may allow sleep effects on emotional memory to be identified and inform study of sleep’s effects on more complex, emotionally salient declarative memories. Anxiety disorders are marked by impairments of both sleep and extinction memory. Improving sleep quality may ameliorate anxiety disorders by strengthening naturally acquired extinction. Strategically timed sleep may be used to enhance treatment of anxiety by strengthening therapeutic extinction learned via exposure therapy. PMID:25894546

  4. Effects of aging on interference control in selective attention and working memory.

    Science.gov (United States)

    Cansino, Selene; Guzzon, Daniela; Martinelli, Massimiliano; Barollo, Michele; Casco, Clara

    2011-11-01

    Working memory decay in advanced age has been attributed to a concurrent decrease in the ability to control interference. The present study contrasted a form of interference control in selective attention that acts upon the perception of external stimuli (access) with another form that operates on internal representations in working memory (deletion), in order to determine both of their effects on working memory efficiency in younger and older adults. Additionally, we compared memory performance under these access and deletion functions to performance in their respective control conditions. The results indicated that memory accuracy improved in both age groups from the access functions, but that only young adults benefited from the deletion functions. In addition, intrusion effects in the deletion condition were larger in older than in younger adults. The ability to control the irrelevant perception- and memory-elicited interference did not decline in general with advancing age; rather, the control mechanisms that operate on internal memory representations declined specifically.

  5. Automaticity of basic-level categorization accounts for labeling effects in visual recognition memory.

    Science.gov (United States)

    Richler, Jennifer J; Gauthier, Isabel; Palmeri, Thomas J

    2011-11-01

    Are there consequences of calling objects by their names? Lupyan (2008) suggested that overtly labeling objects impairs subsequent recognition memory because labeling shifts stored memory representations of objects toward the category prototype (representational shift hypothesis). In Experiment 1, we show that processing objects at the basic category level versus exemplar level in the absence of any overt labeling produces the same qualitative pattern of results. Experiment 2 demonstrates that labeling does not always disrupt memory as predicted by the representational shift hypothesis: Differences in memory following labeling versus preference are more likely an effect of judging preference, not an effect of overt labeling. Labeling does not influence memory by shifting memory representations toward the category prototype. Rather, labeling objects at the basic level produces memory representations that are simply less robust than those produced by other kinds of study tasks.

  6. Randomized controlled trial evaluating the temporal effects of high-intensity exercise on learning, short-term and long-term memory, and prospective memory.

    Science.gov (United States)

    Frith, Emily; Sng, Eveleen; Loprinzi, Paul D

    2017-09-18

    The broader purpose of this study was to examine the temporal effects of high-intensity exercise on learning, short-term and long-term retrospective memory and prospective memory. Among a sample of 88 young adult participants, 22 were randomized into one of four different groups: exercise before learning, control group, exercise during learning, and exercise after learning. The retrospective assessments (learning, short-term and long-term memory) were assessed using the Rey Auditory Verbal Learning Test. Long-term memory including a 20-min and 24-hr follow-up assessment. Prospective memory was assessed using a time-based procedure by having participants contact (via phone) the researchers at a follow-up time period. The exercise stimulus included a 15-min bout of progressive maximal exertion treadmill exercise. High-intensity exercise prior to memory encoding (vs. exercise during memory encoding or consolidation) was effective in enhancing long-term memory (for both 20-min and 24-h follow-up assessments). We did not observe a differential temporal effect of high-intensity exercise on short-term memory (immediate post-memory encoding), learning or prospective memory. The timing of high-intensity exercise may play an important role in facilitating long-term memory. © 2017 Federation of European Neuroscience Societies and John Wiley & Sons Ltd.

  7. Effect of amyloid on memory and non-memory decline from preclinical to clinical Alzheimer's disease.

    Science.gov (United States)

    Lim, Yen Ying; Maruff, Paul; Pietrzak, Robert H; Ames, David; Ellis, Kathryn A; Harrington, Karra; Lautenschlager, Nicola T; Szoeke, Cassandra; Martins, Ralph N; Masters, Colin L; Villemagne, Victor L; Rowe, Christopher C

    2014-01-01

    High amyloid has been associated with substantial episodic memory decline over 18 and 36 months in healthy older adults and individuals with mild cognitive impairment. However, the nature and magnitude of amyloid-related memory and non-memory change from the preclinical to the clinical stages of Alzheimer's disease has not been evaluated over the same time interval. Healthy older adults (n = 320), individuals with mild cognitive impairment (n = 57) and individuals with Alzheimer's disease (n = 36) enrolled in the Australian Imaging, Biomarkers and Lifestyle study underwent at least one positron emission tomography neuroimaging scan for amyloid. Cognitive assessments were conducted at baseline, and 18- and 36-month follow-up assessments. Compared with amyloid-negative healthy older adults, amyloid-positive healthy older adults, and amyloid-positive individuals with mild cognitive impairment and Alzheimer's disease showed moderate and equivalent decline in verbal and visual episodic memory over 36 months (d's = 0.47-0.51). Relative to amyloid-negative healthy older adults, amyloid-positive healthy older adults showed no decline in non-memory functions, but amyloid-positive individuals with mild cognitive impairment showed additional moderate decline in language, attention and visuospatial function (d's = 0.47-1.12), and amyloid-positive individuals with Alzheimer's disease showed large decline in all aspects of memory and non-memory function (d's = 0.73-2.28). Amyloid negative individuals with mild cognitive impairment did not show any cognitive decline over 36 months. When non-demented individuals (i.e. healthy older adults and adults with mild cognitive impairment) were further dichotomized, high amyloid-positive non-demented individuals showed a greater rate of decline in episodic memory and language when compared with low amyloid positive non-demented individuals. Memory decline does not plateau with increasing disease severity, and decline in non-memory

  8. A randomized controlled trial of the effectiveness of handheld computers for improving everyday memory functioning in patients with memory impairments after acquired brain injury.

    Science.gov (United States)

    Lannin, Natasha; Carr, Belinda; Allaous, Jeanine; Mackenzie, Bronwyn; Falcon, Alex; Tate, Robyn

    2014-05-01

    To determine the effectiveness of personal digital assistant devices on achievement of memory and organization goals in patients with poor memory after acquired brain injury. Assessor blinded randomized controlled trial. Specialist brain injury rehabilitation hospital (inpatients and outpatients). Adults with acquired brain impairments (85% traumatic brain injury; aged ≥17 years) who were assessed as having functional memory impairment on the Rivermead Behavioural Memory Test (General Memory Index). Training and support to use a personal digital assistant for eight weeks to compensate for memory failures by an occupational therapist. The control intervention was standard rehabilitation, including use of non-electronic memory aids. Goal Attainment Scale which assessed achievement of participants' daily memory functioning goals and caregiver perception of memory functioning; and General Frequency of Forgetting subscale of the Memory Functioning Questionnaire administered at baseline (pre-randomization) and post intervention (eight weeks later). Forty-two participants with memory impairment were recruited. Use of a personal digital assistant led to greater achievement of functional memory goals (mean difference 1.6 (95% confidence interval (CI) 1.0 to 2.2), P = 0.0001) and improvement on the General Frequency of Forgetting subscale (mean difference 12.5 (95% CI 2.0 to 22.9), P = 0.021). Occupational therapy training in the use of a handheld computer improved patients' daily memory function more than standard rehabilitation.

  9. The Effect of Vocalization on Melodic Memory Conservation.

    Science.gov (United States)

    Pembrook, Randall G.

    1987-01-01

    Reports on a study which reinforces prior findings on melodic memory that show a majority of students do not sing accurately enough after only one hearing of a melody to benefit from vocalization memory techniques. Questions whether vocalization can be a memory reinforcer in melodies that are shorter and simpler than those used in this research.…

  10. The effects of eye movements on emotional memories: using an objective measure of cognitive load

    Science.gov (United States)

    van Veen, Suzanne C.; Engelhard, Iris M.; van den Hout, Marcel A.

    2016-01-01

    Background Eye movement desensitization and reprocessing (EMDR) is an effective treatment for posttraumatic stress disorder. The working memory (WM) theory explains its efficacy: recall of an aversive memory and making eye movements (EM) both produce cognitive load, and competition for the limited WM resources reduces the memory's vividness and emotionality. The present study tested several predictions from WM theory. Objective We hypothesized that 1) recall of an aversive autobiographical memory loads WM compared to no recall, and 2) recall with EM reduces the vividness, emotionality, and cognitive load of recalling the memory more than only recall or only cognitive effort (i.e., recall of an irrelevant memory with EM). Method Undergraduates (N=108) were randomly assigned to one of three conditions: 1) recall relevant memory with EM, 2) recall relevant memory without EM, and 3) recall irrelevant memory with EM. We used a random interval repetition task to measure the cognitive load of recalling the memory. Participants responded to randomly administered beeps, with or without recalling the memory. The degree to which participants slow down during recall provides an index of cognitive load. We measured the cognitive load and self-reported vividness and emotionality before, halfway through (8×24 s), and after (16×24 s) the intervention. Results Reaction times slowed down during memory recall compared to no recall. The recall relevant with EM condition showed a larger decrease in self-reported vividness and emotionality than the control conditions. The cognitive load of recalling the memory also decreased in this condition but not consistently more than in the control conditions. Conclusions Recall of an aversive memory loads WM, but drops in vividness and emotionality do not immediately reduce the cognitive load of recalling the memory. More research is needed to find objective measures that could capture changes in the quality of the memory. Highlights of the

  11. Effects of the swimming exercise on the consolidation and persistence of auditory and contextual fear memory.

    Science.gov (United States)

    Faria, Rodolfo Souza; Gutierres, Luís Felipe Soares; Sobrinho, Fernando César Faria; Miranda, Iris do Vale; Reis, Júlia Dos; Dias, Elayne Vieira; Sartori, Cesar Renato; Moreira, Dalmo Antonio Ribeiro

    2016-08-15

    consolidation as well as persistence of conditioned fear memory. In addition, rats submitted to swimming exercise over six weeks showed an improved performance in the test of auditory-cued fear memory persistence, but not in the test of contextual fear memory persistence. Moreover, no significant effect from swimming exercise was observed on consolidation of both contextual and auditory fear memory. So, our study, revealing the effect of the swimming exercise on different stages of implicit memory of tone/foot shock conditioning, contributes to and complements the current knowledge about the environmental modulation of memory process.

  12. An extended thermo-mechanically coupled algorithm for simulation of superelasticity and shape memory effect in shape memory alloys

    Institute of Scientific and Technical Information of China (English)

    S. HASHEMI; H. AHMADIAN; S. MOHAMMADI

    2015-01-01

    Thermo-mechanical coupling in shape memory alloys is a very complicated phenomenon. The heat generation/absorption during forward/reverse transformation can lead to temperature-dependent variation of its mechanical behavior in the forms of superelasticity and shape memory effect. However, unlike the usual assumption, slow loading rate cannot guarantee an isothermal process. A two-dimensional thermo-mechanically coupled algorithm is proposed based on the original model of Lagoudas to efficiently model both superelasticity and shape memory effects and the influence of various strain rates, aspect ratios and boundary conditions. To implement the coupled model into a finite element code, a numerical staggered algorithm is employed. A number of simulations are performed to verify the proposed approach with available experimental and numerical data and to assess its efficiency in solving complex SMA problems.

  13. Memory effects in chaotic advection of inertial particles

    Science.gov (United States)

    Daitche, Anton; Tél, Tamás

    2014-07-01

    A systematic investigation of the effect of the history force on particle advection is carried out for both heavy and light particles. General relations are given to identify parameter regions where the history force is expected to be comparable with the Stokes drag. As an illustrative example, a paradigmatic two-dimensional flow, the von Kármán flow is taken. For small (but not extremely small) particles all investigated dynamical properties turn out to heavily depend on the presence of memory when compared to the memoryless case: the history force generates a rather non-trivial dynamics that appears to weaken (but not to suppress) inertial effects, it enhances the overall contribution of viscosity. We explore the parameter space spanned by the particle size and the density ratio, and find a weaker tendency for accumulation in attractors and for caustics formation. The Lyapunov exponent of transients becomes larger with memory. Periodic attractors are found to have a very slow, {{t}^{-1/2}} type convergence towards the asymptotic form. We find that the concept of snapshot attractors is useful to understand this slow convergence: an ensemble of particles converges exponentially fast towards a snapshot attractor, which undergoes a slow shift for long times.

  14. Memory Effects in Chaotic Advection of Inertial Particles

    CERN Document Server

    Daitche, Anton

    2014-01-01

    A systematic investigation of the effect of the history force on particle advection is carried out for both heavy and light particles. General relations are given to identify parameter regions where the history force is expected to be comparable with the Stokes drag. As an illustrative example, a paradigmatic two-dimensional flow, the von K\\'arm\\'an flow is taken. For small (but not extremely small) particles all investigated dynamical properties turn out to heavily depend on the presence of memory when compared to the memoryless case: the history force generates a rather nontrivial dynamics that appears to weaken (but not to suppress) inertial effects, it enhances the overall contribution of viscosity. We explore the parameter space spanned by the particle size and the density ratio, and find a weaker tendency for accumulation in attractors and for caustics formation. The Lyapunov exponent of transients becomes larger with memory. Periodic attractors are found to have a very slow, $t^{-1/2}$ type convergence...

  15. Thermal energy conversion by coupled shape memory and piezoelectric effects

    Science.gov (United States)

    Zakharov, Dmitry; Lebedev, Gor; Cugat, Orphee; Delamare, Jerome; Viala, Bernard; Lafont, Thomas; Gimeno, Leticia; Shelyakov, Alexander

    2012-09-01

    This work gives experimental evidence of a promising method of thermal-to-electric energy conversion by coupling shape memory effect (SME) and direct piezoelectric effect (DPE) for harvesting quasi-static ambient temperature variations. Two original prototypes of thermal energy harvesters have been fabricated and tested experimentally. The first is a hybrid laminated composite consisting of TiNiCu shape memory alloy (SMA) and macro fiber composite piezoelectric. This composite comprises 0.1 cm3 of active materials and harvests 75 µJ of energy for each temperature variation of 60 °C. The second prototype is a SME/DPE ‘machine’ which uses the thermally induced linear strains of the SMA to bend a bulk PZT ceramic plate through a specially designed mechanical structure. The SME/DPE ‘machine’ with 0.2 cm3 of active material harvests 90 µJ over a temperature increase of 35 °C (60 µJ when cooling). In contrast to pyroelectric materials, such harvesters are also compatible with both small and slow temperature variations.

  16. A gravitational memory effect in "boosted" black hole perturbation theory

    CERN Document Server

    Gleiser, R J; Dominguez, Alfredo E.; Gleiser, Reinaldo J.

    2003-01-01

    Black hole perturbation theory, or more generally, perturbation theory on a Schwarzschild bockground, has been applied in several contexts, but usually under the simplifying assumption that the ADM momentum vanishes, namely, that the evolution is carried out and observed in the ``center of momentum frame''. In this paper we consider some consequences of the inclusion of a non vanishing ADM momentum in the initial data. We first provide a justification for the validity of the transformation of the initial data to the ``center of momentum frame'', and then analyze the effect of this transformation on the gravitational wave amplitude. The most significant result is the possibility of a type of gravitational memory effect that appears to have no simple relation with the well known Christodoulou effect.

  17. Effects of memory strategy training on performance and event-related brain potentials of children with ADHD in an episodic memory task.

    Science.gov (United States)

    Jonkman, Lisa M; Hurks, Petra P; Schleepen, Tamara M J

    2016-10-01

    Evidence for memory problems in children with attention deficit hyperactivity disorder (ADHD) is accumulating. Attempting to counter such problems, in the present study children with ADHD aged 8-12 years underwent a six-week metacognitive memory strategy training (MST) or one of two other active trainings, either a metacognitive attention-perceptual-motor training (APM) or placebo training consisting of playing board games (PLA). Effects of the training on episodic memory and underlying brain processes were investigated by comparing performance and event-related brain potentials (ERPs) on pre- and post-training sessions in an old/new recognition task between the three training groups. Potential far transfer effects of the memory strategy training were investigated by measuring performance on neuropsychological attention and memory-span tasks and parent-rated ADHD symptoms. The metacognitive memory strategy training led to significantly improved memory performance and enhanced amplitude of left parietal P600 activity associated with the process of memory recollection when compared to PLA, but APM training evoked similar improvements. Memory performance gains were significantly correlated with the memory-related ERP effects. Preliminary far transfer effects of MST training were found on attention and working memory performance and on parent-rated ADHD symptoms, although these results need replication with larger and better IQ-matched groups.

  18. Memory of psychodiagnostic information: biases and effects of expertise.

    Science.gov (United States)

    Brailey, K; Vasterling, J J; Franks, J J

    2001-01-01

    Problem-solving expertise has been associated with enhanced memory of domain-specific information. This enhanced memory is thought to play an important role in expert decisions. Meanwhile, research on psychodiagnostic decision making has found consistent limitations in experienced clinicians' ability to make optimal decisions. To what extent are these limitations associated with suboptimal memory processes? We compared memories of expert clinicians and novice graduate students for information learned while viewing a videotaped psychodiagnostic interview. Results of 3 tests suggest that expert clinicians exhibit enhanced memory that is flexible, selective, and accurate but with limitations that might contribute to poor decisions. Experts exhibited superior memory of personal criteria and disconfirmatory information. However, a framing manipulation induced performance in experts consistent with suboptimal decision making, and both groups needed exhaustive prompts for optimal memory search. Implications of these findings for expertise models are discussed.

  19. The Effects of Goal Relevance and Perceptual Features on Emotional Items and Associative Memory

    Directory of Open Access Journals (Sweden)

    Wei B. Mao

    2017-07-01

    Full Text Available Showing an emotional item in a neutral background scene often leads to enhanced memory for the emotional item and impaired associative memory for background details. Meanwhile, both top–down goal relevance and bottom–up perceptual features played important roles in memory binding. We conducted two experiments and aimed to further examine the effects of goal relevance and perceptual features on emotional items and associative memory. By manipulating goal relevance (asking participants to categorize only each item image as living or non-living or to categorize each whole composite picture consisted of item image and background scene as natural scene or manufactured scene and perceptual features (controlling visual contrast and visual familiarity in two experiments, we found that both high goal relevance and salient perceptual features (high salience of items vs. high familiarity of items could promote emotional item memory, but they had different effects on associative memory for emotional items and neutral backgrounds. Specifically, high goal relevance and high perceptual-salience of items could jointly impair the associative memory for emotional items and neutral backgrounds, while the effect of item familiarity on associative memory for emotional items would be modulated by goal relevance. High familiarity of items could increase associative memory for negative items and neutral backgrounds only in the low goal relevance condition. These findings suggest the effect of emotion on associative memory is not only related to attentional capture elicited by emotion, but also can be affected by goal relevance and perceptual features of stimulus.

  20. Effects of task instruction on autobiographical memory specificity in young and older adults.

    Science.gov (United States)

    Ford, Jaclyn Hennessey; Rubin, David C; Giovanello, Kelly S

    2014-01-01

    Older adults tend to retrieve autobiographical information that is overly general (i.e., not restricted to a single event, termed the overgenerality effect) relative to young adults' specific memories. A vast majority of studies that have reported overgenerality effects explicitly instruct participants to retrieve specific memories, thereby requiring participants to maintain task goals, inhibit inappropriate responses, and control their memory search. Since these processes are impaired in healthy ageing, it is important to determine whether such task instructions influence the magnitude of the overgenerality effect in older adults. In the current study participants retrieved autobiographical memories during presentation of musical clips. Task instructions were manipulated to separate age-related differences in the specificity of underlying memory representations from age-related differences in following task instructions. Whereas young adults modulated memory specificity based on task demands, older adults did not. These findings suggest that reported rates of overgenerality in older adults' memories might include age-related differences in memory representation, as well as differences in task compliance. Such findings provide a better understanding of the underlying cognitive mechanisms involved in age-related changes in autobiographical memory and may also be valuable for future research examining effects of overgeneral memory on general well-being.

  1. Effects of Task Instruction on Autobiographical Memory Specificity in Young and Older Adults

    Science.gov (United States)

    Ford, Jaclyn Hennessey; Rubin, David C.; Giovanello, Kelly S.

    2013-01-01

    Older adults tend to retrieve autobiographical information that is overly general (i.e. not restricted to a single event, termed the overgenerality effect) relative to young adults’ specific memories. A vast majority of studies that have reported overgenerality effects explicitly instruct participants to retrieve specific memories, thereby requiring participants to maintain task goals, inhibit inappropriate responses, and control their memory search. Since these processes are impaired in healthy aging, it is important to determine whether such task instructions influence the magnitude of the overgenerality effect in older adults. In the current study, participants retrieved autobiographical memories during presentation of musical clips. Task instructions were manipulated to separate age-related differences in the specificity of underlying memory representations from age-related differences in following task instructions. Whereas young adults modulated memory specificity based on task demands, older adults did not. These findings suggest that reported rates of overgenerality in older adults’ memories may include age-related differences in memory representation, as well as differences in task compliance. Such findings provide a better understanding of the underlying cognitive mechanisms involved in age-related changes in autobiographical memory and may also be valuable for future research examining effects of overgeneral memory on general well-being. PMID:23915176

  2. Effect of solution hardening on the shape memory effect of Fe-Mn based alloys

    Energy Technology Data Exchange (ETDEWEB)

    Tsuzaki, K.; Natsume, Y.; Maki, T. [Kyoto Univ. (Japan). Dept. of Materials Science and Engineering; Tomota, Y. [Ibaraki Univ., Hitachi (Japan)

    1995-10-01

    Fe-high Mn-Si alloys, which undergo {gamma} (fcc) to {var_epsilon} (hcp) martensitic transformation, exhibit a pronounced shape memory effect. The origin of shape memory effect of these alloys is the reversion of stress-induced {var_epsilon} martensite. A shape change must hence be accomplish3ed by stress-induced martensitic transformation without permanent slip in austenite ({gamma}) in order to obtain a good shape memory effect. It is clear that the intrusion of permanent slip can be suppressed by increasing the strength of austenite and by decreasing the applied stress required for a shape change due to stress-induced martensitic transformation. It has been reported that the addition of the interstitial elements of C and N as well as the substitutional elements of Mo and V increases the 0.2% proof stress of austenite in Fe-high Mn alloys. However, there have been few studies on the effect of these alloying elements on the shape memory effect of Fe-high Mn based alloys. In the present study, it was aimed to improve the shape memory effect of Fe-high Mn based alloys by the strengthening of austenite through solution hardening due to C and Mo.

  3. Dose-dependent effects of hydrocortisone infusion on autobiographical memory recall.

    Science.gov (United States)

    Young, Kymberly; Drevets, Wayne C; Schulkin, Jay; Erickson, Kristine

    2011-10-01

    The glucocorticoid hormone cortisol has been shown to impair episodic memory performance. The present study examined the effect of two doses of hydrocortisone (synthetic cortisol) administration on autobiographical memory retrieval. Healthy volunteers (n = 66) were studied on two separate visits, during which they received placebo and either moderate-dose (0.15 mg/kg IV; n = 33) or high-dose (0.45 mg/kg IV; n = 33) hydrocortisone infusion. From 75 to 150 min post-infusion subjects performed an Autobiographical Memory Test and the California Verbal Learning Test (CVLT). The high-dose hydrocortisone administration reduced the percent of specific memories recalled (p = .04), increased the percent of categorical (nonspecific) memories recalled (p cortisol affects accessibility of autobiographical memories in a dose-dependent manner. Specifically, administration of hydrocortisone at doses analogous to those achieved under severe psychosocial stress impaired the specificity and speed of retrieval of autobiographical memories.

  4. Process estimation in the presence of time-invariant memory effects

    Science.gov (United States)

    Rybár, Tomáš; Ziman, Mário

    2015-10-01

    Any repeated use of a fixed experimental instrument is subject to memory effects. We design an estimation method uncovering the details of the underlying interaction between the system and the internal memory without having any experimental access to memory degrees of freedom. In such case, by definition, any memoryless quantum process tomography (QPT) fails because the observed data sequences do not satisfy the elementary condition of statistical independence. However, we show that the randomness implemented in certain QPT schemes is sufficient to guarantee the emergence of observable "statistical" patterns containing complete information on the memory channels. We demonstrate the algorithm in detail for the case of qubit memory channels with two-dimensional memory. Interestingly, we find that for the arbitrary estimation method, the memory channels generated by controlled unitary interactions are indistinguishable from memoryless unitary channels.

  5. The Effects of Spatial Contextual Familiarity on Remembered Scenes, Episodic Memories, and Imagined Future Events

    Science.gov (United States)

    Robin, Jessica; Moscovitch, Morris

    2014-01-01

    Several recent studies have explored the effect of contextual familiarity on remembered and imagined events. The aim of this study was to examine the extent of this effect by comparing the effect of cuing spatial memories, episodic memories, and imagined future events with spatial contextual cues of varying levels of familiarity. We used…

  6. Individual Differences in the Effects of Retrieval from Long-Term Memory

    Science.gov (United States)

    Brewer, Gene A.; Unsworth, Nash

    2012-01-01

    The current study examined individual differences in the effects of retrieval from long-term memory (i.e., the testing effect). The effects of retrieving from memory make tested information more accessible for future retrieval attempts. Despite the broad applied ramifications of such a potent memorization technique there is a paucity of research…

  7. Individual Differences in the Effects of Retrieval from Long-Term Memory

    Science.gov (United States)

    Brewer, Gene A.; Unsworth, Nash

    2012-01-01

    The current study examined individual differences in the effects of retrieval from long-term memory (i.e., the testing effect). The effects of retrieving from memory make tested information more accessible for future retrieval attempts. Despite the broad applied ramifications of such a potent memorization technique there is a paucity of research…

  8. Deja Vu All Over Again: Effects of Reenactment on Toddlers' Event Memory.

    Science.gov (United States)

    Sheffield, Ellyn G.; Hudson, Judith A.

    1998-01-01

    Four experiments examined the effects of reenactment on 18-month-olds' event memory. Results indicated that reenacting novel activities in a laboratory playroom improved event memory. Reenactment was more effective after a time delay, and the effects of timing of reenactment were more pronounced after a six-month delay. Reenacting half of the…

  9. The Effect of Overgeneral Autobiographical Memory Retrieval on Rumination

    Directory of Open Access Journals (Sweden)

    Filip Raes

    2006-03-01

    Full Text Available From distinct research traditions rumination and overgeneral autobiographical memory retrieval (OGM have emerged as two vulnerability markers for depression and depressive relapse (Nolen-Hoeksema, 2004; Williams, 2004. Recent research further suggests a causal relation between rumination and OGM (e.g., Watkins & Teasdale, 2001. The present study investigated the inverse relationship, that is, OGM causally influencing ruminative thinking. A scrambled sentences procedure was used to assess the extent to which 112 student participants were engaged in a mental mode consistent with ruminative thinking following either a specific or overgeneral memory retrieval style manipulation. Trait rumination was also assessed prior to the experimental retrieval manipulation, using a self-report scale. It was found that high ruminators, following an overgeneral (as compared to a specific retrieval style, unscrambled sentences relatively more into sentences with a ruminative meaning. In non or low ruminators this retrieval style manipulation had no such effect. Alongside the findings of Watkins and colleagues (e.g., Watkins & Teasdale, 2001, the present results are consistent with the view of rumination and OGM as two mutually reinforcing vulnerability factors for depression (Williams, 1996, 2004.

  10. Magnetic memory effect in chelated zero valent iron nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, N., E-mail: nilotpal@vit.ac.in [School of Advanced Sciences, VIT University, Vellore 632014, Tamilnadu (India); Mandal, B.K.; Mohan Kumar, K. [School of Advanced Sciences, VIT University, Vellore 632014, Tamilnadu (India)

    2012-11-15

    We report the study of nonequilibrium magnetic behavior of air stable zero valent iron nanoparticles synthesized in presence of N-cetyl-N,N,N-trimethyl ammonium bromide chelating agent. X-ray photoelectron spectroscopy study has suggested the presence of iron oxides on nZVI surfaces. Zero-field-cooled and field-cooled magnetization measurements have been carried out at 20-300 K and 100 Oe. For field-cooled measurements with 1 h stops at 200, 100 and 50 K when compared with the warming cycle, we found the signature of magnetic memory effect. A study of magnetic relaxation at the same temperatures shows the existence of two relaxation times. - Highlights: Black-Right-Pointing-Pointer Zero valent iron nanoparticles are synthesized with CTAB chelating agent. Black-Right-Pointing-Pointer X-ray photoelectron spectroscopy study has shown the presence of iron oxide. Black-Right-Pointing-Pointer Magnetization measurement has displayed signature of magnetic memory. Black-Right-Pointing-Pointer Magnetization measurement with time suggested presence of 2 relaxation times.

  11. The effect of background music on episodic memory and autonomic responses: listening to emotionally touching music enhances facial memory capacity.

    Science.gov (United States)

    Proverbio, Alice Mado; Mado Proverbio, C A Alice; Lozano Nasi, Valentina; Alessandra Arcari, Laura; De Benedetto, Francesco; Guardamagna, Matteo; Gazzola, Martina; Zani, Alberto

    2015-10-15

    The aim of this study was to investigate how background auditory processing can affect other perceptual and cognitive processes as a function of stimulus content, style and emotional nature. Previous studies have offered contrasting evidence, and it has been recently shown that listening to music negatively affected concurrent mental processing in the elderly but not in young adults. To further investigate this matter, the effect of listening to music vs. listening to the sound of rain or silence was examined by administering an old/new face memory task (involving 448 unknown faces) to a group of 54 non-musician university students. Heart rate and diastolic and systolic blood pressure were measured during an explicit face study session that was followed by a memory test. The results indicated that more efficient and faster recall of faces occurred under conditions of silence or when participants were listening to emotionally touching music. Whereas auditory background (e.g., rain or joyful music) interfered with memory encoding, listening to emotionally touching music improved memory and significantly increased heart rate. It is hypothesized that touching music is able to modify the visual perception of faces by binding facial properties with auditory and emotionally charged information (music), which may therefore result in deeper memory encoding.

  12. The effect of background music on episodic memory and autonomic responses: listening to emotionally touching music enhances facial memory capacity

    Science.gov (United States)

    Mado Proverbio, C.A. Alice; Lozano Nasi, Valentina; Alessandra Arcari, Laura; De Benedetto, Francesco; Guardamagna, Matteo; Gazzola, Martina; Zani, Alberto

    2015-01-01

    The aim of this study was to investigate how background auditory processing can affect other perceptual and cognitive processes as a function of stimulus content, style and emotional nature. Previous studies have offered contrasting evidence, and it has been recently shown that listening to music negatively affected concurrent mental processing in the elderly but not in young adults. To further investigate this matter, the effect of listening to music vs. listening to the sound of rain or silence was examined by administering an old/new face memory task (involving 448 unknown faces) to a group of 54 non-musician university students. Heart rate and diastolic and systolic blood pressure were measured during an explicit face study session that was followed by a memory test. The results indicated that more efficient and faster recall of faces occurred under conditions of silence or when participants were listening to emotionally touching music. Whereas auditory background (e.g., rain or joyful music) interfered with memory encoding, listening to emotionally touching music improved memory and significantly increased heart rate. It is hypothesized that touching music is able to modify the visual perception of faces by binding facial properties with auditory and emotionally charged information (music), which may therefore result in deeper memory encoding. PMID:26469712

  13. Marijuana effects on the speed of memory retrieval in the letter-matching task.

    Science.gov (United States)

    Block, R I; Wittenborn, J R

    1986-02-01

    Marijuana's effect on the speed of retrieving simple information from memory was studied using a task in which subjects saw two letters and decided whether or not they had the same name. Subjects smoked a single marijuana or placebo cigarette under double-blind conditions. Marijuana slowed reaction time relative to placebo, but this effect was not influenced by the demands on memory retrieval or by providing advance information relevant to the required decisions, suggesting that memory retrieval was unimpaired.

  14. The Effects of Acute Physical Exercise on Memory, Peripheral BDNF, and Cortisol in Young Adults

    OpenAIRE

    Kirsten Hötting; Nadine Schickert; Jochen Kaiser; Brigitte Röder; Maren Schmidt-Kassow

    2016-01-01

    In animals, physical activity has been shown to induce functional and structural changes especially in the hippocampus and to improve memory, probably by upregulating the release of neurotrophic factors. In humans, results on the effect of acute exercise on memory are inconsistent so far. Therefore, the aim of the present study was to assess the effects of a single bout of physical exercise on memory consolidation and the underlying neuroendocrinological mechanisms in young adults. Participan...

  15. A molecular dynamics investigation of the deformation mechanism and shape memory effect of epoxy shape memory polymers

    Science.gov (United States)

    Yang, Hua; Wang, ZhengDao; Guo, YaFang; Shi, XingHua

    2016-03-01

    Following deformation, thermally induced shape memory polymers (SMPs) have the ability to recover their original shape with a change in temperature. In this work, the thermomechanical properties and shape memory behaviors of three types of epoxy SMPs with varying curing agent contents were investigated using a molecular dynamics (MD) method. The mechanical properties under uniaxial tension at different temperatures were obtained, and the simulation results compared reasonably with experimental data. In addition, in a thermomechanical cycle, ideal shape memory effects for the three types of SMPs were revealed through the shape frozen and shape recovery responses at low and high temperatures, respectively, indicating that the recovery time is strongly influenced by the ratio of E-51 to 4,4'-Methylenedianiline.

  16. Are addiction-related memories malleable by working memory competition? Transient effects on memory vividness and nicotine craving in a randomized lab experiment.

    Science.gov (United States)

    Markus, Wiebren; de Weert-van Oene, Gerdien H; Woud, Marcella L; Becker, Eni S; DeJong, Cornelis A J

    2016-09-01

    Experimental research suggests that working memory (WM) taxation reduces craving momentarily. Using a modified Eye Movement Desensitization and Reprocessing (EMDR) procedure, prolonged reductions in craving and relapse rates in alcohol dependence have been demonstrated. Modified EMDR-procedures may also hold promise in smoking cessation attempts. A proof-of-concept study was conducted to narrow the gap between WM-taxation experiments and clinical EMDR studies. To this end the clinical EMDR-procedure was modified for use in a laboratory experiment. Daily smokers (n = 47), abstaining overnight, were allocated (by minimization randomization) to one of two groups using a parallel design. In both cases a modified EMDR-procedure was used. In the experimental group (n = 24) eye movements (EM) were induced while control group participants (n = 23) fixed their gaze (not taxing WM). During 6 min trials, craving-inducing memories were recalled. Craving, vividness of target memories, and smoking behavior were assessed at several variable-specific time-points between baseline (one week pre-intervention) and one week follow-up. The experimental group showed significant immediate reductions of craving and vividness of targeted memories. However, these effects were lost during a one-week follow-up period. A limited dose of WM-taxation, in the form of EM in a modified EMDR-procedure, resulted in transient effects on memory vividness and nicotine craving. EM provide a valuable way of coping with the acute effects of craving during smoking cessation attempts. Other aspects of the EMDR-procedure may provide additional effects. Component and dose-response studies are needed to establish the potential of EMDR-therapy in smoking cessation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Facilitative Effects of Forgetting from Short-Term Memory on Growth of Long-Term Memory in Retardates

    Science.gov (United States)

    Sperber, Richard D.

    1976-01-01

    Competing explanations of the beneficial effect of spacing in retardate discrimination learning were tested. Results are inconsistent with consolidation and rehearsal theories but support the prediction of the Geber, Greenfield, and House spacing model that forgetting from short-term memory facilities retardate learning. (Author/SB)

  18. Temporal effects of dehydroepiandrosterone sulfate on memory formation in day-old chicks.

    Science.gov (United States)

    Sujkovic, E; Mileusnic, R; Fry, J P; Rose, S P R

    2007-08-24

    Dehydroepiandrosterone sulfate (DHEAS) has been shown to enhance memory retention in different animal models and in various learning paradigms. In the present study, we investigated the effect of peripherally administered DHEAS on the acquisition, consolidation and retention of memory using a weak version of the one-trial passive avoidance task in day-old chicks. Intraperitoneally administered DHEAS (20 mg/kg) either 30 min before or 30 min and 4.5 h after training on the weakly aversive stimulus, enhanced recall at 24 h following training, suggesting a potentiation of not only the acquisition but also the early and late phases of memory consolidation. In contrast, when DHEAS was administered at 30 min prior to the 24 h retention test there was no memory enhancement, indicating a lack of effect on memory retrieval. Memory recall was unaltered when DHEAS was administered at 30 min before training in a control group trained on a strongly aversive stimulus, confirming memory-specific effects. Interestingly, the memory enhancement appeared to be sex-specific as male chicks showed higher recall than females. These findings provide further evidence that DHEAS enhances memory and may be involved in the temporal cascade of long-term memory formation.

  19. Models for Total-Dose Radiation Effects in Non-Volatile Memory

    Energy Technology Data Exchange (ETDEWEB)

    Campbell, Philip Montgomery; Wix, Steven D.

    2017-04-01

    The objective of this work is to develop models to predict radiation effects in non- volatile memory: flash memory and ferroelectric RAM. In flash memory experiments have found that the internal high-voltage generators (charge pumps) are the most sensitive to radiation damage. Models are presented for radiation effects in charge pumps that demonstrate the experimental results. Floating gate models are developed for the memory cell in two types of flash memory devices by Intel and Samsung. These models utilize Fowler-Nordheim tunneling and hot electron injection to charge and erase the floating gate. Erase times are calculated from the models and compared with experimental results for different radiation doses. FRAM is less sensitive to radiation than flash memory, but measurements show that above 100 Krad FRAM suffers from a large increase in leakage current. A model for this effect is developed which compares closely with the measurements.

  20. The Electromagnetic Christodoulou Memory Effect and its Application to Neutron Star Binary Mergers

    CERN Document Server

    Bieri, Lydia; Yau, Shing-Tung

    2011-01-01

    Gravitational waves are predicted by the general theory of relativity. It has been shown that gravitational waves have a nonlinear memory, displacing test masses permanently. This is called the Christodoulou memory. We proved that the electromagnetic field contributes at highest order to the nonlinear memory effect of gravitational waves, enlarging the permanent displacement of test masses. In experiments like LISA or LIGO which measure distances of test masses, the Christodoulou memory will manifest itself as a permanent displacement of these objects. It has been suggested to detect the Christodoulou memory effect using radio telescopes investigating small changes in pulsar's pulse arrival times. The latter experiments are based on present-day technology and measure changes in frequency. In the present paper, we study the electromagnetic Christodoulou memory effect and compute it for binary neutron star mergers. These are typical sources of gravitational radiation. During these processes, not only mass and m...

  1. The effects of road traffic noise and meaningful irrelevant speech on different memory systems.

    Science.gov (United States)

    Hygge, Staffan; Boman, Eva; Enmarker, Ingela

    2003-02-01

    To explore why noise has reliable effects on delayed recall in a certain text-reading task, this episodic memory task was employed with other memory tests in a study of road traffic noise and meaningful but irrelevant speech. Context-dependent memory was tested and self-reports of affect were taken. Participants were 96 high school students. The results showed that both road traffic noise and meaningful irrelevant speech impaired recall of the text. Retrieval in noise from semantic memory was also impaired. Attention was impaired by both noise sources, but attention did not mediate the noise effects on episodic memory. Recognition was not affected by noise. Context-dependent memory was not shown. The lack of mediation by attention, and road traffic noise being as harmful as meaningful irrelevant speech, are discussed in relation to where in the input/storing/output sequence noise has its effect and what the distinctive feature of the disturbing noise is.

  2. Effect of Training on Two-way Shape Memory Effect and Its Stability in a Ti-Ni-Hf High Temperature Shape Memory Alloy

    Institute of Scientific and Technical Information of China (English)

    Xianglong MENG; Wei CAI; K.T. LAU; L.M. ZHOU; Liancheng ZHAO

    2003-01-01

    The Effect of the thermal cycling training under constant strain on the two-way shape memory effect (TWSME) in a Ti36Ni49Hf15 high temperature shape memory alloy (SMA) has been investigated by bending tests. The results indicated that the training procedure is beneficial to get the better TWSME. The two-way shape memory strain increases with increasing the training strain. And it decreases with increasing the training temperature. The TWSME obtained in the present alloy shows poorer stability compared with that obtained in the TiNi alloys.

  3. The Cambridge Car Memory Test: a task matched in format to the Cambridge Face Memory Test, with norms, reliability, sex differences, dissociations from face memory, and expertise effects.

    Science.gov (United States)

    Dennett, Hugh W; McKone, Elinor; Tavashmi, Raka; Hall, Ashleigh; Pidcock, Madeleine; Edwards, Mark; Duchaine, Bradley

    2012-06-01

    Many research questions require a within-class object recognition task matched for general cognitive requirements with a face recognition task. If the object task also has high internal reliability, it can improve accuracy and power in group analyses (e.g., mean inversion effects for faces vs. objects), individual-difference studies (e.g., correlations between certain perceptual abilities and face/object recognition), and case studies in neuropsychology (e.g., whether a prosopagnosic shows a face-specific or object-general deficit). Here, we present such a task. Our Cambridge Car Memory Test (CCMT) was matched in format to the established Cambridge Face Memory Test, requiring recognition of exemplars across view and lighting change. We tested 153 young adults (93 female). Results showed high reliability (Cronbach's alpha = .84) and a range of scores suitable both for normal-range individual-difference studies and, potentially, for diagnosis of impairment. The mean for males was much higher than the mean for females. We demonstrate independence between face memory and car memory (dissociation based on sex, plus a modest correlation between the two), including where participants have high relative expertise with cars. We also show that expertise with real car makes and models of the era used in the test significantly predicts CCMT performance. Surprisingly, however, regression analyses imply that there is an effect of sex per se on the CCMT that is not attributable to a stereotypical male advantage in car expertise.

  4. Contrasting Effects of Histone Deacetylase Inhibitors on Reward and Aversive Olfactory Memories in the Honey Bee

    Directory of Open Access Journals (Sweden)

    Gabrielle A Lockett

    2014-06-01

    Full Text Available Much of what we have learnt from rodent models about the essential role of epigenetic processes in brain plasticity has made use of aversive learning, yet the role of histone acetylation in aversive memory in the honey bee, a popular invertebrate model for both memory and epigenetics, was previously unknown. We examined the effects of histone deacetylase (HDAC inhibition on both aversive and reward olfactory associative learning in a discrimination proboscis extension reflex (PER assay. We report that treatment with the HDAC inhibitors APHA compound 8 (C8, phenylbutyrate (PB or sodium butyrate (NaB impaired discrimination memory due to impairment of aversive memory in a dose-dependent manner, while simultaneously having no effect on reward memory. Treatment with C8 1 h before training, 1 h after training or 1 h before testing, impaired aversive but not reward memory at test. C8 treatment 1 h before training also improved aversive but not reward learning during training. PB treatment only impaired aversive memory at test when administered 1 h after training, suggesting an effect on memory consolidation specifically. Specific impairment of aversive memory (but not reward memory by HDAC inhibiting compounds was robust, reproducible, occurred following treatment with three drugs targeting the same mechanism, and is likely to be genuinely due to alterations to memory as sucrose sensitivity and locomotion were unaffected by HDAC inhibitor treatment. This pharmacological dissection of memory highlights the involvement of histone acetylation in aversive memory in the honey bee, and expands our knowledge of epigenetic control of neural plasticity in invertebrates.

  5. Reverse Shape Memory Effect Related to α → γ Transformation in a Fe-Mn-Al-Ni Shape Memory Alloy

    Science.gov (United States)

    Peng, Huabei; Huang, Pan; Zhou, Tiannan; Wang, Shanling; Wen, Yuhua

    2017-05-01

    In this study, we investigated the shape memory behavior and phase transformations of solution-treated Fe43.61Mn34.74Al13.38Ni8.27 alloy between room temperature and 1173 K (900 °C). This alloy exhibits the reverse shape memory effect resulting from the phase transformation of α (bcc) → γ (fcc) between 673 K and 1073 K (400 °C and 800 °C) in addition to the shape memory effect resulting from the martensitic reverse transformation of γ' (fcc) → α (bcc) below 673 K (400 °C). There is a high density of hairpin-shaped dislocations in the α phase undergoing the martensitic reverse transformation of γ' → α. The lath γ phase, which preferentially nucleates and grows in the reversed α phase, has the same crystal orientation with the reverse-transformed γ' martensite. However, the vermiculate γ phase, which is precipitated in the α phase between lath γ phase, has different crystal orientations. The lath γ phase is beneficial to attaining better reverse shape memory effect than the vermiculate γ phase.

  6. The target effect: visual memory for unnamed search targets.

    Science.gov (United States)

    Thomas, Mark D; Williams, Carrick C

    2014-01-01

    Search targets are typically remembered much better than other objects even when they are viewed for less time. However, targets have two advantages that other objects in search displays do not have: They are identified categorically before the search, and finding them represents the goal of the search task. The current research investigated the contributions of both of these types of information to the long-term visual memory representations of search targets. Participants completed either a predefined search or a unique-object search in which targets were not defined with specific categorical labels before searching. Subsequent memory results indicated that search target memory was better than distractor memory even following ambiguously defined searches and when the distractors were viewed significantly longer. Superior target memory appears to result from a qualitatively different representation from those of distractor objects, indicating that decision processes influence visual memory.

  7. Consolidation differentially modulates schema effects on memory for items and associations.

    Directory of Open Access Journals (Sweden)

    Marlieke T R van Kesteren

    Full Text Available Newly learned information that is congruent with a preexisting schema is often better remembered than information that is incongruent. This schema effect on memory has previously been associated to more efficient encoding and consolidation mechanisms. However, this effect is not always consistently supported in the literature, with differential schema effects reported for different types of memory, different retrieval cues, and the possibility of time-dependent effects related to consolidation processes. To examine these effects more directly, we tested participants on two different types of memory (item recognition and associative memory for newly encoded visuo-tactile associations at different study-test intervals, thus probing memory retrieval accuracy for schema-congruent and schema-incongruent items and associations at different time points (t = 0, t = 20, and t = 48 hours after encoding. Results show that the schema effect on visual item recognition only arises after consolidation, while the schema effect on associative memory is already apparent immediately after encoding, persisting, but getting smaller over time. These findings give further insight into different factors influencing the schema effect on memory, and can inform future schema experiments by illustrating the value of considering effects of memory type and consolidation on schema-modulated retrieval.

  8. Modulatory mechanisms of cortisol effects on emotional learning and memory: novel perspectives.

    Science.gov (United States)

    van Ast, Vanessa A; Cornelisse, Sandra; Marin, Marie-France; Ackermann, Sandra; Garfinkel, Sarah N; Abercrombie, Heather C

    2013-09-01

    It has long been known that cortisol affects learning and memory processes. Despite a wealth of research dedicated to cortisol effects on learning and memory, the strength or even directionality of the effects often vary. A number of the factors that alter cortisol's effects on learning and memory are well-known. For instance, effects of cortisol can be modulated by emotional arousal and the memory phase under study. Despite great advances in understanding factors that explain variability in cortisol's effects, additional modulators of cortisol effects on memory exist that are less widely acknowledged in current basic experimental research. The goal of the current review is to disseminate knowledge regarding less well-known modulators of cortisol effects on learning and memory. Since several models for the etiology of anxiety, such as post-traumatic stress disorder (PTSD), incorporate stress and the concomitant release of cortisol as important vulnerability factors, enhanced understanding of mechanisms by which cortisol exerts beneficial as opposed to detrimental effects on memory is very important. Further elucidation of the factors that modulate (or alter) cortisol's effects on memory will allow reconciliation of seemingly inconsistent findings in the basic and clinical literatures. The present review is based on a symposium as part of the 42nd International Society of Psychoneuroendocrinology Conference, New York, USA, that highlighted some of those modulators and their underlying mechanisms.

  9. Effectiveness of Working Memory Training among Subjects Currently on Sick Leave Due to Complex Symptoms

    Science.gov (United States)

    Aasvik, Julie K.; Woodhouse, Astrid; Stiles, Tore C.; Jacobsen, Henrik B.; Landmark, Tormod; Glette, Mari; Borchgrevink, Petter C.; Landrø, Nils I.

    2017-01-01

    Introduction: The current study examined if adaptive working memory training (Cogmed QM) has the potential to improve inhibitory control, working memory capacity, and perceptions of memory functioning in a group of patients currently on sick leave due to symptoms of pain, insomnia, fatigue, depression and anxiety. Participants who were referred to a vocational rehabilitation center volunteered to take part in the study. Methods: Participants were randomly assigned to either a training condition (N = 25) or a control condition (N = 29). Participants in the training condition received working memory training in addition to the clinical intervention offered as part of the rehabilitation program, while participants in the control condition received treatment as usual i.e., the rehabilitation program only. Inhibitory control was measured by The Stop Signal Task, working memory was assessed by the Spatial Working Memory Test, while perceptions of memory functioning were assessed by The Everyday Memory Questionnaire-Revised. Results: Participants in the training group showed a significant improvement on the post-tests of inhibitory control when compared with the comparison group (p = 0.025). The groups did not differ on the post-tests of working memory. Both groups reported less memory problems at post-testing, but there was no sizeable difference between the two groups. Conclusions: Results indicate that working memory training does not improve general working memory capacity per se. Nor does it seem to give any added effects in terms of targeting and improving self-perceived memory functioning. Results do, however, provide evidence to suggest that inhibitory control is accessible and susceptible to modification by adaptive working memory training. PMID:28111555

  10. Thermoelectric Seebeck effect in oxide-based resistive switching memory.

    Science.gov (United States)

    Wang, Ming; Bi, Chong; Li, Ling; Long, Shibing; Liu, Qi; Lv, Hangbing; Lu, Nianduan; Sun, Pengxiao; Liu, Ming

    2014-08-20

    Reversible resistive switching induced by an electric field in oxide-based resistive switching memory shows a promising application in future information storage and processing. It is believed that there are some local conductive filaments formed and ruptured in the resistive switching process. However, as a fundamental question, how electron transports in the formed conductive filament is still under debate due to the difficulty to directly characterize its physical and electrical properties. Here we investigate the intrinsic electronic transport mechanism in such conductive filament by measuring thermoelectric Seebeck effects. We show that the small-polaron hopping model can well describe the electronic transport process for all resistance states, although the corresponding temperature-dependent resistance behaviours are contrary. Moreover, at low resistance states, we observe a clear semiconductor-metal transition around 150 K. These results provide insight in understanding resistive switching process and establish a basic framework for modelling resistive switching behaviour.

  11. Cholinergic basis of memory improving effect of Ocimum tenuiflorum linn

    Directory of Open Access Journals (Sweden)

    Joshi H

    2006-01-01

    Full Text Available Dementia is one of the age-related mental problems and a characteristic symptom of Alzheimer′s disease. Nootropic agents are used in situations where there is organic disorder in learning abilities. The present work was undertaken to assess the potential of Ocimum tenuiflorum Linn. as a nootropic and anticholinesterase agent in mice. Ethanol extract of dried whole plant of O. tenuiflorum Linn. ameliorated the amnesic effect of scopolamine (0.4 mg/kg and aging-induced memory deficits in mice. Passive avoidance paradigm served as the exteroceptive behavioural model. O. tenuiflorum extract increased step-down latency and acetyl cholinesterase inhibition significantly. Hence, O. tenuiflorum can be employed in the treatment of cognitive disorders such as dementia and Alzheimer′s disease.

  12. Pseudo Memory Effects, Majorization and Entropy in Quantum Random Walks

    CERN Document Server

    Bracken, A J; Tsohantjis, I; Bracken, Anthony J.; Ellinas, Demosthenes; Tsohantjis, Ioannis

    2004-01-01

    A quantum random walk on the integers exhibits pseudo memory effects, in that its probability distribution after N steps is determined by reshuffling the first N distributions that arise in a classical random walk with the same initial distribution. In a classical walk, entropy increase can be regarded as a consequence of the majorization ordering of successive distributions. The Lorenz curves of successive distributions for a symmetric quantum walk reveal no majorization ordering in general. Nevertheless, entropy can increase, and computer experiments show that it does so on average. Varying the stages at which the quantum coin system is traced out leads to new quantum walks, including a symmetric walk for which majorization ordering is valid but the spreading rate exceeds that of the usual symmetric quantum walk.

  13. Neutrino Radiation Showing a Christodoulou Memory Effect in General Relativity

    CERN Document Server

    Bieri, Lydia

    2013-01-01

    We describe neutrino radiation in general relativity by introducing the energy-momentum tensor of a null fluid into the Einstein equations. Investigating the geometry and analysis at null infinity, we prove that a component of the null fluid enlarges the Christodoulou memory effect of gravitational waves. The description of neutrinos in general relativity as a null fluid can be regarded as a limiting case of a more general description using the massless limit of the Einstein-Vlasov system. The present authors with co-authors have work in progress to generalize the results of this paper using this more general description. Gigantic neutrino bursts occur in our universe in core-collapse supernovae and in the mergers of neutron star binaries.

  14. The Effect of Radiation "Memory" in Alkali-Halide Crystals

    Science.gov (United States)

    Korovkin, M. V.; Sal'nikov, V. N.

    2017-01-01

    The exposure of the alkali-halide crystals to ionizing radiation leads to the destruction of their structure, the emergence of radiation defects, and the formation of the electron and hole color centers. Destruction of the color centers upon heating is accompanied by the crystal bleaching, luminescence, and radio-frequency electromagnetic emission (REME). After complete thermal bleaching of the crystal, radiation defects are not completely annealed, as the electrons and holes released from the color centers by heating leave charged and locally uncompensated defects. Clusters of these "pre centers" lead to electric microheterogeneity of the crystal, the formation of a quasi-electret state, and the emergence of micro-discharges accompanied by radio emission. The generation of REME associated with residual defectiveness, is a manifestation of the effect of radiation "memory" in dielectrics.

  15. Graded effects of social conformity on recognition memory.

    Science.gov (United States)

    Axmacher, Nikolai; Gossen, Anna; Elger, Christian E; Fell, Juergen

    2010-02-17

    Previous studies have shown that the opinion of confederates in a group influences recognition memory, but inconsistent results have been obtained concerning the question of whether recognition of items as old and new are affected similarly, possibly because only one or two confederates are present during the recognition phase. Here, we present data from a study where recognition of novel faces was tested in the presence of four confederates. In a long version of this experiment, recognition of items as old and new was similarly affected by group responses. However, in the short version, recognition of old items depended proportionally on the number of correct group responses, while rejection of new items only decreased significantly when all confederates gave an incorrect response. These findings indicate that differential effects of social conformity on recognition of items as old and new occur in situations with an intermediate level of group pressure.

  16. Ferroelectric-gate field effect transistor memories device physics and applications

    CERN Document Server

    Ishiwara, Hiroshi; Okuyama, Masanori; Sakai, Shigeki; Yoon, Sung-Min

    2016-01-01

    This book provides comprehensive coverage of the materials characteristics, process technologies, and device operations for memory field-effect transistors employing inorganic or organic ferroelectric thin films. This transistor-type ferroelectric memory has interesting fundamental device physics and potentially large industrial impact. Among the various applications of ferroelectric thin films, the development of nonvolatile ferroelectric random access memory (FeRAM) has progressed most actively since the late 1980s and has achieved modest mass production levels for specific applications since 1995. There are two types of memory cells in ferroelectric nonvolatile memories. One is the capacitor-type FeRAM and the other is the field-effect transistor (FET)-type FeRAM. Although the FET-type FeRAM claims ultimate scalability and nondestructive readout characteristics, the capacitor-type FeRAMs have been the main interest for the major semiconductor memory companies, because the ferroelectric FET has fatal handic...

  17. The effects of sequential attention shifts within visual working memory

    Directory of Open Access Journals (Sweden)

    Qi eLi

    2014-09-01

    Full Text Available Previous studies have shown conflicting data as to whether it is possible to sequentially shift spatial attention among visual working memory (VWM representations. The present study investigated this issue by asynchronously presenting attentional cues during the retention interval of a change detection task. In particular, we focused on two types of sequential attention shifts: 1 orienting attention to one location, and then withdrawing attention from it, and 2 switching the focus of attention from one location to another. In Experiment 1, a withdrawal cue was presented after a spatial retro-cue to measure the effect of withdrawing attention. The withdrawal cue significantly reduced the cost of invalid spatial cues, but surprisingly, did not attenuate the benefit of valid spatial cues. This indicates that the withdrawal cue only triggered the activation of facilitative components but not inhibitory components of attention. In Experiment 2, two spatial retro-cues were presented successively to examine the effect of switching the focus of attention. We observed benefits of both the first and second cues in sequential cueing, indicating that participants were able to reorient attention from one location to another within VWM, and the reallocation of attention did not attenuate memory at the first cued location. In Experiment 3, we found that reducing the validity of the preceding spatial cue did lead to a significant reduction in its benefit. However, performance at the first-cued location was still better than the neutral baseline or performance at the uncued locations, indicating that the first cue benefit might have been preserved both partially under automatic control and partially under voluntary control. Our findings revealed new properties of dynamic attentional control in VWM maintenance.

  18. Simulation of grain size effects in nanocrystalline shape memory alloys

    Science.gov (United States)

    Ahluwalia, Rajeev; Quek, Siu Sin; Wu, David T.

    2015-06-01

    Recently, it has been demonstrated that martensitic transformation in nanocrystalline shape memory alloys can be suppressed for small grain sizes. Motivated by these results, we study the grain size dependence of martensitic transformations and stress-strain response of nanocrystalline shape memory alloys within the framework of the Ginzburg-Landau (GL) theory. A GL model for a square to rectangle transformation in polycrystals is extended to account for grain boundary effects. We propose that an inhibition of the transformation in grain boundary regions can occur, if the grain boundary energy of the martensite is higher than that of the austenite phase. We show that this inhibition of transformation in grain boundary regions has a strong influence on domain patterns inside grains. Although the transformation is inhibited only at the grain boundaries, it leads to a suppression of the transformation even inside the grains as grain size is decreased. In fact, below a critical grain size, the transformation can be completely suppressed. We explain these results in terms of the extra strain gradient cost associated with grain boundaries, when the transformation is inhibited at grain boundaries. On the other hand, no significant size effects are observed when transformation is not inhibited at grain boundaries. We also study the grain size dependence of the stress strain curve. It is found that when the transformation is inhibited at grain boundaries, a significant reduction in the hysteresis associated with stress-strain curves during the loading-unloading cycles is observed. The hysteresis for this situation reduces even further as the grain size is reduced, which is consistent with recent experiments. The simulations also demonstrate that the mechanical behavior is influenced by inter-granular interactions and the local microstructural neighbourhood of a grain has a stronger influence than the orientation of the grain itself.

  19. Mann-Type Extragradient Methods for General Systems of Variational Inequalities with Multivalued Variational Inclusion Constraints in Banach Spaces

    Directory of Open Access Journals (Sweden)

    Lu-Chuan Ceng

    2013-01-01

    Full Text Available We introduce Mann-type extragradient methods for a general system of variational inequalities with solutions of a multivalued variational inclusion and common fixed points of a countable family of nonexpansive mappings in real smooth Banach spaces. Here the Mann-type extragradient methods are based on Korpelevich’s extragradient method and Mann iteration method. We first consider and analyze a Mann-type extragradient algorithm in the setting of uniformly convex and 2-uniformly smooth Banach space and then another Mann-type extragradient algorithm in a smooth and uniformly convex Banach space. Under suitable assumptions, we derive some weak and strong convergence theorems. The results presented in this paper improve, extend, supplement, and develop the corresponding results announced in the earlier and very recent literature.

  20. Fourth meeting entitled “Visualization and Processing of Tensors and Higher Order Descriptors for Multi-Valued Data”

    CERN Document Server

    Vilanova, Anna; Burgeth, Bernhard; Visualization and Processing of Tensors and Higher Order Descriptors for Multi-Valued Data

    2014-01-01

    Arising from the fourth Dagstuhl conference entitled Visualization and Processing of Tensors and Higher Order Descriptors for Multi-Valued Data (2011), this book offers a broad and vivid view of current work in this emerging field. Topics covered range from applications of the analysis of tensor fields to research on their mathematical and analytical properties. Part I, Tensor Data Visualization, surveys techniques for visualization of tensors and tensor fields in engineering, discusses the current state of the art and challenges, and examines tensor invariants and glyph design, including an overview of common glyphs. The second Part, Representation and Processing of Higher-order Descriptors, describes a matrix representation of local phase, outlines mathematical morphological operations techniques, extended for use in vector images, and generalizes erosion to the space of diffusion weighted MRI. Part III, Higher Order Tensors and Riemannian-Finsler Geometry, offers powerful mathematical language to model and...

  1. Effects of Transcranial Direct Current Stimulation (tDCS) on Human Memory.

    Energy Technology Data Exchange (ETDEWEB)

    Matzen, Laura E.; Trumbo, Michael Christopher Stefan

    2014-10-01

    Training a person in a new knowledge base or skill set is extremely time consuming and costly, particularly in highly specialized domains such as the military and the intelligence community. Recent research in cognitive neuroscience has suggested that a technique called transcranial direct current stimulation (tDCS) has the potential to revolutionize training by enabling learners to acquire new skills faster, more efficiently, and more robustly (Bullard et al., 2011). In this project, we tested the effects of tDCS on two types of memory performance that are critical for learning new skills: associative memory and working memory. Associative memory is memory for the relationship between two items or events. It forms the foundation of all episodic memories, so enhancing associative memory could provide substantial benefits to the speed and robustness of learning new information. We tested the effects of tDCS on associative memory, using a real-world associative memory task: remembering the links between faces and names. Working memory refers to the amount of information that can be held in mind and processed at one time, and it forms the basis for all higher-level cognitive processing. We investigated the degree of transfer between various working memory tasks (the N-back task as a measure of verbal working memory, the rotation-span task as a measure of visuospatial working memory, and Raven's progressive matrices as a measure of fluid intelligence) in order to determine if tDCS-induced facilitation of performance is task-specific or general.

  2. Effect of glatiramer acetate on short-term memory impairment induced by lipopolysaccharide in male mice.

    Science.gov (United States)

    Mohammadi, Fatemeh; Rahimian, Reza; Fakhraei, Nahid; Rezayat, Seyed Mahdi; Javadi-Paydar, Mehrak; Dehpour, Ahmad R; Afshari, Khashayar; Ejtemaei Mehr, Shahram

    2016-08-01

    Glatiramer acetate (GA) demonstrates neuroprotective, neurogenesis, and anti-inflammatory properties. This study examines the probable protective effect of acute GA on lipopolysaccharide (LPS)-induced memory impairment in male mice and further explores which routes of administration [subcutaneous (s.c.) or intracerebroventricular (i.c.v.)] exert optimum effect. Memory performance was evaluated in two-trial recognition Y-maze and passive-avoidance tasks evaluating special recognition memory and fear memory, respectively. Memory impairment was induced by LPS [100 μg/kg, intraperitoneally (i.p.)], 4 h before training. In Y-maze, GA (10, 2.5, 0.625, 0.153, and 0.03 mg/kg, s.c.; 250 μg/mouse; i.c.v.) was administered 10 min following LPS, and special memory was assayed in Y-maze apparatus. In passive avoidance, LPS (100, 250 μg/kg; i.p.) was injected 4 h before receiving foot shock, and GA (10, 2.5; s.c.) or (250 μg/mouse; i.c.v.) was administered 4 h before the shock. Following 24 h, the fear memory was evaluated. Memory impaired significantly following LPS (100, 250 μg/kg; i.p.) in Y-maze and passive-avoidance tasks, P maze reversed memory impairment (LPS 100 μg/kg, i.p.) (P mice showed significantly longer latency times during the retention trial (P memory impairment both centrally and systemically. It improved spatial recognition memory increasing the average time in the novel arm and improved fear memory increasing latency time. GA administration improved memory impairment profoundly through both systemic and central routs.

  3. Memory conformity affects inaccurate memories more than accurate memories.

    Science.gov (United States)

    Wright, Daniel B; Villalba, Daniella K

    2012-01-01

    After controlling for initial confidence, inaccurate memories were shown to be more easily distorted than accurate memories. In two experiments groups of participants viewed 50 stimuli and were then presented with these stimuli plus 50 fillers. During this test phase participants reported their confidence that each stimulus was originally shown. This was followed by computer-generated responses from a bogus participant. After being exposed to this response participants again rated the confidence of their memory. The computer-generated responses systematically distorted participants' responses. Memory distortion depended on initial memory confidence, with uncertain memories being more malleable than confident memories. This effect was moderated by whether the participant's memory was initially accurate or inaccurate. Inaccurate memories were more malleable than accurate memories. The data were consistent with a model describing two types of memory (i.e., recollective and non-recollective memories), which differ in how susceptible these memories are to memory distortion.

  4. Evaluation of shape memory effect and damping characteristics of Cu–Al–Be–Mn shape memory alloys

    Directory of Open Access Journals (Sweden)

    A.G. Shivasiddaramaiah

    2016-09-01

    Full Text Available Among different shape memory alloys, copper (Cu based alloys were the most favourable alloys, because of their attaining price and good characteristic properties. In this present work different weight compositions of Cu–Al–Be–Mn shape memory alloys are considered and are in the range of 10–14 wt% of aluminium (Al, 0.4–0.5 wt% of beryllium (Be and 0.3–0.4 wt% of manganese (Mn and these alloys were synthesized by ingot metallurgy, which exhibits β-phase at higher temperatures, also demonstrates a shape memory effect (SME after quenching to room temperature. The Be, Mn and Al content was varied in different sets to study the shape memory effect and damping behaviour of the alloys by using differential scanning calorimetry and dynamic mechanical analyzer respectively. These alloys exhibit higher damping or internal friction in the martensitic condition and internal friction or damping peak in the transition zone.

  5. Brain Mechanisms of Social Threat Effects on Working Memory.

    Science.gov (United States)

    van Ast, V A; Spicer, J; Smith, E E; Schmer-Galunder, S; Liberzon, I; Abelson, J L; Wager, T D

    2016-02-01

    Social threat can have adverse effects on cognitive performance, but the brain mechanisms underlying its effects are poorly understood. We investigated the effects of social evaluative threat on working memory (WM), a core component of many important cognitive capabilities. Social threat impaired WM performance during an N-back task and produced widespread reductions in activation in lateral prefrontal cortex and intraparietal sulcus (IPS), among other regions. In addition, activity in frontal and parietal regions predicted WM performance, and mediation analyses identified regions in the bilateral IPS that mediated the performance-impairing effects of social threat. Social threat also decreased connectivity between the IPS and dorsolateral prefrontal cortex, while increasing connectivity between the IPS and the ventromedial prefrontal cortex, a region strongly implicated in the generation of autonomic and emotional responses. Finally, cortisol response to the stressor did not mediate WM impairment but was rather associated with protective effects. These results provide a basis for understanding interactions between social and cognitive processes at a neural systems level.

  6. Differential Effects of Stress-induced Cortisol Responses on Recollection and Familiarity-based Recognition Memory

    OpenAIRE

    McCullough, Andrew M.; Ritchey, Maureen; Ranganath, Charan; Yonelinas, Andrew

    2015-01-01

    Stress-induced changes in cortisol can impact memory in various ways. However, the precise relationship between cortisol and recognition memory is still poorly understood. For instance, there is reason to believe that stress could differentially affect recollection-based memory, which depends on the hippocampus, and familiarity-based recognition, which can be supported by neocortical areas alone. Accordingly, in the current study we examined the effects of stress-related changes in cortisol o...

  7. The Effectiveness of a Working Memory Training Regimen for Iranian University Students: Implications for Medical Students

    OpenAIRE

    Gholam Reza Kiany; Bahman Mehraban; Reza Ghafar Samar

    2016-01-01

    Introduction: Working memory is thought to serve as a part of memory structure where functions like temporary storage and manipulation of information take place. This study investigates the effectiveness of working memory training regimens with Iranian university students, while considering the implications for medical students. Methods: Thirty university students studying at different universities in Kermanshah took part in the study. They were divided into two groups as the experimental...

  8. Resting-state fMRI evidence for early episodic memory consolidation: effects of age.

    Science.gov (United States)

    Kukolja, Juraj; Göreci, D Yasemin; Onur, Özgür A; Riedl, Valentin; Fink, Gereon R

    2016-09-01

    Aging-related episodic memory decline is often attributed to insufficient encoding of new information, although the underlying neural processes remain elusive. We here tested the hypothesis that impaired memory consolidation contributes to aging-related memory decline. To this end, we used resting state functional magnetic resonance imaging in healthy young and older adults and investigated neural network connectivity underlying episodic memory consolidation and the effects of aging thereon. During postencoding rest, connectivity increased in subregions of temporobasal and temporo-occipital networks but decreased in a precuneal network. These connectivity changes predicted subsequent memory performance thereby constituting functional correlates of early memory consolidation. Furthermore, these consolidation-related regional connectivity changes partially overlapped with encoding-related neural activity changes, suggesting a close relationship between encoding- and consolidation-related activity. Older when compared to young participants failed to increase connectivity in the right lingual gyrus as part of an extended default mode network during consolidation, thereby providing a functional correlate for spatial contextual memory deficits. In conclusion, results are consistent with previous reports of persistent activity in regions mediating memory encoding as a core mechanism underlying episodic memory consolidation. Our data extend previous findings suggesting that aging-related memory decline results from a reduction of consolidation processes.

  9. No Acute Effects of Choline Bitartrate Food Supplements on Memory in Healthy, Young, Human Adults.

    Science.gov (United States)

    Lippelt, D P; van der Kint, S; van Herk, K; Naber, M

    2016-01-01

    Choline is a dietary component and precursor of acetylcholine, a crucial neurotransmitter for memory-related brain functions. In two double-blind, placebo-controlled cross-over experiments, we investigated whether the food supplement choline bitartrate improved declarative memory and working memory in healthy, young students one to two hours after supplementation. In experiment 1, 28 participants performed a visuospatial working memory task. In experiment 2, 26 participants performed a declarative picture memorization task. In experiment 3, 40 participants performed a verbal working memory task in addition to the visuospatial working memory and declarative picture task. All tasks were conducted approximately 60 minutes after the ingestion of 2.0-2.5g of either choline bitartrate or placebo. We found that choline did not significantly enhance memory performance during any of the tasks. The null hypothesis that choline does not improve memory performance as compared to placebo was strongly supported by Bayesian statistics. These results are in contrast with animal studies suggesting that choline supplementation boosts memory performance and learning. We conclude that choline likely has no acute effects on cholinergic memory functions in healthy human participants.

  10. Testing the effectiveness of group-based memory rehabilitation in chronic stroke patients.

    Science.gov (United States)

    Miller, Laurie A; Radford, Kylie

    2014-01-01

    Memory complaints are common after stroke, yet there have been very few studies of the outcome of memory rehabilitation in these patients. The present study evaluated the effectiveness of a new manualised, group-based memory training programme. Forty outpatients with a single-stroke history and ongoing memory complaints were enrolled. The six-week course involved education and strategy training and was evaluated using a wait-list crossover design, with three assessments conducted 12 weeks apart. Outcome measures included: tests of anterograde memory (Rey Auditory Verbal Learning Test: RAVLT; Complex Figure Test) and prospective memory (Royal Prince Alfred Prospective Memory Test); the Comprehensive Assessment of Prospective Memory (CAPM) questionnaire and self-report of number of strategies used. Significant training-related gains were found on RAVLT learning and delayed recall and on CAPM informant report. Lower baseline scores predicted greater gains for several outcome measures. Patients with higher IQ or level of education showed more gains in number of strategies used. Shorter time since onset was related to gains in prospective memory, but no other stroke-related variables influenced outcome. Our study provides evidence that a relatively brief, group-based training intervention can improve memory functioning in chronic stroke patients and clarified some of the baseline factors that influence outcome.

  11. No Acute Effects of Choline Bitartrate Food Supplements on Memory in Healthy, Young, Human Adults.

    Directory of Open Access Journals (Sweden)

    D P Lippelt

    Full Text Available Choline is a dietary component and precursor of acetylcholine, a crucial neurotransmitter for memory-related brain functions. In two double-blind, placebo-controlled cross-over experiments, we investigated whether the food supplement choline bitartrate improved declarative memory and working memory in healthy, young students one to two hours after supplementation. In experiment 1, 28 participants performed a visuospatial working memory task. In experiment 2, 26 participants performed a declarative picture memorization task. In experiment 3, 40 participants performed a verbal working memory task in addition to the visuospatial working memory and declarative picture task. All tasks were conducted approximately 60 minutes after the ingestion of 2.0-2.5g of either choline bitartrate or placebo. We found that choline did not significantly enhance memory performance during any of the tasks. The null hypothesis that choline does not improve memory performance as compared to placebo was strongly supported by Bayesian statistics. These results are in contrast with animal studies suggesting that choline supplementation boosts memory performance and learning. We conclude that choline likely has no acute effects on cholinergic memory functions in healthy human participants.

  12. A prerequisite for the effective transfer of the shape-memory effect to cotton fibers

    Science.gov (United States)

    Liem, H.; Yeung, L. Y.; Hu, J. L.

    2007-06-01

    Subtle interaction between shape-memory polymer and cellulose fibers within fabrics remains a critical issue for understanding their thermal-mechanical properties and thus the shape-memory behavior in cotton fibers. We demonstrate here the efficacy of Raman spectroscopy to probe the induced stresses in warp and weft fibers, presenting physicochemical features for cellulose fibers finished with macromolecule polyurethane and small-molecule dimethyloldihydroxyethyleneurea. Accordingly, a possible mechanism for transfer of the shape-memory effect to fabrics is proposed. Forming as a coating on the fiber surface after the finishing process, the shape-memory polymer takes a critical role in reducing the residual stress in weft fibers, establishing the prerequisite for reserving the shape-memory effect to fabric. In addition, this work has demonstrated that Raman spectroscopy is able to probe the residual stresses in cotton fabrics after being treated by chemicals in addition to that due to physical deformation. Our result provides clear evidence that in the finishing process strength reduction in fibers in general is not only caused solely by a chemical reaction, but also by a physical modification of the cotton structure.

  13. The effect of transcendental meditation on iconic memory.

    Science.gov (United States)

    Frumkin, L R; Pagano, R R

    1979-12-01

    Three experiments investigated the effects of transcendental meditation (TM) on iconic memory. The task involved reporting of digits shown tachistoscopically, using Sperling's partial-report technique. Experiment 1 was a pilot study involving a meditation group and a nonmeditation gropu. All subjects were run in a pretest/treatment/posttest design. During the treatment phase the meditation group practiced TM for a 20-minute period and the nonmeditation group relaxed with eyes closed. The results showed that the treatment increased performance in meditators, but not in nonmeditators. In this experiment important controls such as individual administration of the task, extrinsic rewards, subject pacing, and adequate practice were lacking. Experiment 2 was a replication of the first, with these controls added. The results no longer showed a superiority for the meditation treatment. In fact, the meditation group performed worse on each day of running. Experiment 3 was a replication of Experiment 1, to assess whether the meditation effect of Experiment 1 was due to (a) differential increased attention of the meditators (minimized in subject-paced Experiment 2), (b) a gain early in learning for the meditators that was eliminated due to practice in Experiment 2, or (c) a lack of proper control procedures in Experiment 1. The performance of the meditators was, again, significantly lower. This research illustrates the importance of careful control when investigating the effects of meditation on behavior. It also suggests that the effects of meditation may depend on which hemisphere is dominant in performing the task.

  14. Effects of Propranolol, a β-noradrenergic Antagonist, on Memory Consolidation and Reconsolidation in Mice.

    Science.gov (United States)

    Villain, Hélène; Benkahoul, Aïcha; Drougard, Anne; Lafragette, Marie; Muzotte, Elodie; Pech, Stéphane; Bui, Eric; Brunet, Alain; Birmes, Philippe; Roullet, Pascal

    2016-01-01

    Memory reconsolidation impairment using the β-noradrenergic receptor blocker propranolol is a promising novel treatment avenue for patients suffering from pathogenic memories, such as post-traumatic stress disorder (PTSD). However, in order to better inform targeted treatment development, the effects of this compound on memory need to be better characterized via translational research. We examined the effects of systemic propranolol administration in mice undergoing a wide range of behavioral tests to determine more specifically which aspects of the memory consolidation and reconsolidation are impaired by propranolol. We found that propranolol (10 mg/kg) affected memory consolidation in non-aversive tasks (object recognition and object location) but not in moderately (Morris water maze (MWM) to highly (passive avoidance, conditioned taste aversion) aversive tasks. Further, propranolol impaired memory reconsolidation in the most and in the least aversive tasks, but not in the moderately aversive task, suggesting its amnesic effect was not related to task aversion. Moreover, in aquatic object recognition and location tasks in which animals were forced to behave (contrary to the classic versions of the tasks); propranolol did not impair memory reconsolidation. Taken together our results suggest that the memory impairment observed after propranolol administration may result from a modification of the emotional valence of the memory rather than a disruption of the contextual component of the memory trace. This is relevant to the use of propranolol to block memory reconsolidation in individuals with PTSD, as such a treatment would not erase the traumatic memory but only reduce the emotional valence associated with this event.

  15. Effects of propranolol, a β-noradrenergic antagonist, on memory consolidation and reconsolidation in mice

    Directory of Open Access Journals (Sweden)

    Hélène eVillain

    2016-03-01

    Full Text Available Memory reconsolidation impairment using the β-noradrenergic receptor blocker propranolol is a promising novel treatment avenue for patients suffering from pathogenic memories, such as post-traumatic stress disorder (PTSD. However, in order to better inform targeted treatment development, the effects of this compound on memory need to be better characterized via translational research. We examined the effects of systemic propranolol administration in mice undergoing a wide range of behavioral tests to determine more specifically which aspects of the memory consolidation and reconsolidation are impaired by propranolol. We found that propranolol (10mg/kg affected memory consolidation in non-aversive tasks (object recognition and object location but not in moderately (Morris water maze to highly (passive avoidance, conditioned taste aversion aversive tasks. Further, propranolol impaired memory reconsolidation in the most and in the least aversive tasks, but not in the moderately aversive task, suggesting its amnesic effect was not related to task aversion. Moreover, in aquatic object recognition and location tasks in which animals were forced to behave (contrary to the classic versions of the tasks; propranolol did not impair memory reconsolidation. Taken together our results suggest that the memory impairment observed after propranolol administration may result from a modification of the emotional valence of the memory rather than a disruption of the contextual component of the memory trace. This is relevant to the use of propranolol to block memory reconsolidation in individuals with PTSD, as such a treatment would not erase the traumatic memory but only reduce the emotional valence associated with this event.

  16. Shape-memory effect in amorphous potato starch: The influence of local orders and paracrystallinity.

    Science.gov (United States)

    Chevigny, Chloé; Foucat, Loïc; Rolland-Sabaté, Agnès; Buléon, Alain; Lourdin, Denis

    2016-08-01

    In this paper, a detailed characterization of the mechanisms at the origin of the shape-memory effect in amorphous potato starch is presented. Using different treatments (annealing) and preparation methods (hot casting and extrusion), the local structures responsible for the shape-memory were disrupted, as evidenced in the first part of the article detailing the macroscopic properties: mechanical, calorimetric and shape-memory. In the second part the macromolecular scale is investigated using X-rays diffraction and CP-MAS NMR, and thus allows making the link between the structural differences and the macroscopic properties. Finally we discuss the origin of shape-memory in amorphous starch.

  17. The effects of study task on prestimulus subsequent memory effects in the hippocampus.

    Science.gov (United States)

    de Chastelaine, Marianne; Rugg, Michael D

    2015-11-01

    Functional magnetic resonance imaging (fMRI) was employed to examine the effects of a study task manipulation on pre-stimulus activity in the hippocampus predictive of later successful recollection. Eighteen young participants were scanned while making either animacy or syllable judgments on visually presented study words. Cues presented before each word denoted which judgment should be made. Following the study phase, a surprise recognition memory test was administered in which each test item had to be endorsed as "Remembered," "Known," or "New." As expected, "deep" animacy judgments led to better memory for study items than did "shallow" syllable judgments. In both study tasks, pre-stimulus subsequent recollection effects were evident in the interval between the cue and the study item in bilateral anterior hippocampus. However, the direction of the effects differed according to the study task: whereas pre-stimulus hippocampal activity on animacy trials was greater for later recollected items than items judged old on the basis of familiarity (replicating prior findings), these effects reversed for syllable trials. We propose that the direction of pre-stimulus hippocampal subsequent memory effects depends on whether an optimal pre-stimulus task set facilitates study processing that is conducive or unconducive to the formation of contextually rich episodic memories. © 2015 Wiley Periodicals, Inc.

  18. Toxic effect of khat (Catha edulis) on memory: Systematic review and meta-analysis

    Science.gov (United States)

    Berihu, Birhane Alem; Asfeha, Gebrekidan Gebregzabher; Welderufael, Abadi Leul; Debeb, Yared Godefa; Zelelow, Yibrah Berhe; Beyene, Hafte Assefa

    2017-01-01

    Background: People use khat (Catha edulis) for its pleasant stimulant effect of physical activity, consciousness, motor, and mental functions. Although there are reports assessing the effect of khat on memory, there was no study based on formal systematic review and meta-analysis. Objective: We have therefore conducted this meta-analysis to determine the level of evidence for the effect of khat (C. edulis Forsk) on memory discrepancy. Methods: MEDLINE, Cochrane Library, PubMed, Academic Search Complete, SPORTDiscus, ScienceDirect, Scopus, Web of Science, and Google Scholar were searched to retrieve the papers for this review. Keywords utilized across database search were khat, cat, chat, long-term memory, short-term memory, memory deficit, randomized control trial, and cross-sectional survey. The search was limited to studies in humans and rodents; published in English language. Result: Finding of various studies included in our meta-analysis showed that the effect of acute, and subchronic exposure to khat showed that short-term memory appears to be affected depending on the duration of exposure. However, does not have any effect on long-term memory. Conclusion: Although a number of studies regarding the current topic are limited, the evidenced showed that khat (C. edulis) induced memory discrepancy. PMID:28149078

  19. Attention and memory evaluation across the life span: heterogeneous effects of age and education.

    Science.gov (United States)

    Gómez-Pérez, Esther; Ostrosky-Solís, Feggy

    2006-05-01

    The developmental sequences of attention and memory were studied by utilizing normative data derived from the neuropsychological battery named NEUROPSI ATTENTION AND MEMORY. A sample of 521 Spanish-speaking individuals, aged 6 to 85 years, participated in this study. In the adult sample, educational level ranged from 0 to 22 years of education. Data from subtests measuring orientation, attention and concentration, executive functions, working memory, immediate and delayed verbal memory, and immediate and delayed visual memory were included. The factor structure of the analyzed battery is presented. The effects of age and education on this structure were analyzed. Results suggested that although attention and memory are related, their developmental sequences are separated from one another. During childhood, the development of selective and sustained attention, attentional-working memory, and executive functions showed a fast improvement in performance. Development of verbal memory and place and person orientation showed a slower increment in scores. In the adult sample it was found that factors related to memory are sensitive to age, whereas those related to attention and executive functions are sensitive to education. The consideration of both the developmental sequence, as well as differential effects of education, can improve the sensitivity and specificity of neuropsychological measures, allowing early diagnosis of cognitive dysfunction and implementation of adequate rehabilitation programs.

  20. [Effect of opioid receptors on acute stress-induced changes in recognition memory].

    Science.gov (United States)

    Liu, Ying; Wu, Yu-Wei; Qian, Zhao-Qiang; Yan, Cai-Fang; Fan, Ka-Min; Xu, Jin-Hui; Li, Xiao; Liu, Zhi-Qiang

    2016-12-25

    Although ample evidence has shown that acute stress impairs memory, the influences of acute stress on different phases of memory, such as acquisition, consolidation and retrieval, are different. Experimental data from both human and animals support that endogenous opioid system plays a role in stress, as endogenous opioid release is increased and opioid receptors are activated during stress experience. On the other hand, endogenous opioid system mediates learning and memory. The aim of the present study was to investigate the effect of acute forced swimming stress on recognition memory of C57 mice and the role of opioid receptors in this process by using a three-day pattern of new object recognition task. The results showed that 15-min acute forced swimming damaged the retrieval of recognition memory, but had no effect on acquisition and consolidation of recognition memory. No significant change of object recognition memory was found in mice that were given naloxone, an opioid receptor antagonist, by intraperitoneal injection. But intraperitoneal injection of naloxone before forced swimming stress could inhibit the impairment of recognition memory retrieval caused by forced swimming stress. The results of real-time PCR showed that acute forced swimming decreased the μ opioid receptor mRNA levels in whole brain and hippocampus, while the injection of naloxone before stress could reverse this change. These results suggest that acute stress may impair recognition memory retrieval via opioid receptors.

  1. Stress memory effect in viscoelastic stagnant lid convection

    Science.gov (United States)

    Patočka, V.; Čadek, O.; Tackley, P. J.; Čížková, H.

    2017-06-01

    Present thermochemical convection models of planetary evolution often assume a purely viscous or viscoplastic rheology. Ignoring elasticity in the cold, outer boundary layer is, however, questionable since elastic effects may play an important role there and affect surface topography as well as the stress distribution within the stiff cold lithosphere. Here we present a modelling study focused on the combined effects of Maxwell viscoelastic rheology and a free surface in the stagnant lid planetary convection. We implemented viscoelastic rheology in the StagYY code using a tracer-based stress advection scheme that suppresses subgrid oscillations. We apply this code to perform thermal convection models of the cooling planetary mantles and we demonstrate that while the global characteristics of the mantle flow do not change significantly when including viscoelasticity, the stress state of the cold lithosphere may be substantially different. Transient cooling of an initially thin upper thermal boundary layer results in a complex layered stress structure due to the memory effects of viscoelastic rheology. The stress state of the lid may thus contain a record of the planetary thermal evolution.

  2. Effects of piracetam on behavior and memory in adult zebrafish.

    Science.gov (United States)

    Grossman, Leah; Stewart, Adam; Gaikwad, Siddharth; Utterback, Eli; Wu, Nadine; Dileo, John; Frank, Kevin; Hart, Peter; Howard, Harry; Kalueff, Allan V

    2011-04-25

    Piracetam, a derivative of γ-aminobutyric acid, exerts memory-enhancing and mild anxiolytic effects in human and rodent studies. To examine the drug's behavioral profile further, we assessed its effects on behavioral and endocrine (cortisol) responses of adult zebrafish (Danio rerio)--a novel model species rapidly gaining popularity in neurobehavioral research. Overall, acute piracetam did not affect zebrafish novel tank and light-dark box behavior at mild doses (25-400mg/L), but produced nonspecific behavioral inhibition at 700mg/L. No effects on cortisol levels or inter-/intra-session habituation in the novel tank test were observed for acute or chronic mild non-sedative dose of 200mg/L. In contrast, fish exposed to chronic piracetam at this dose performed significantly better in the cued learning plus-maze test. This observation parallels clinical and rodent literature on the behavioral profile of piracetam, supporting the utility of zebrafish paradigms for testing nootropic agents. Copyright © 2011 Elsevier Inc. All rights reserved.

  3. Approximation of a Common Element of the Fixed Point Sets of Multivalued Strictly Pseudocontractive-Type Mappings and the Set of Solutions of an Equilibrium Problem in Hilbert Spaces

    Directory of Open Access Journals (Sweden)

    F. O. Isiogugu

    2016-01-01

    Full Text Available The strong convergence of a hybrid algorithm to a common element of the fixed point sets of multivalued strictly pseudocontractive-type mappings and the set of solutions of an equilibrium problem in Hilbert spaces is obtained using a strict fixed point set condition. The obtained results improve, complement, and extend the results on multivalued and single-valued mappings in the contemporary literature.

  4. The effect of medial temporal lobe epilepsy on visual memory encoding.

    Science.gov (United States)

    Gregory, A M; Nenert, R; Allendorfer, J B; Martin, R; Kana, R K; Szaflarski, J P

    2015-05-01

    Effective visual memory encoding, a function important for everyday functioning, relies on episodic and semantic memory processes. In patients with medial temporal lobe epilepsy (MTLE), memory deficits are common as the structures typically involved in seizure generation are also involved in acquisition, maintenance, and retrieval of episodic memories. In this study, we used group independent component analysis (GICA) combined with Granger causality analysis to investigate the neuronal networks involved in visual memory encoding during a complex fMRI scene-encoding task in patients with left MTLE (LMTLE; N=28) and in patients with right MTLE (RMTLE; N=18). Additionally, we built models of memory encoding in LMTLE and RMTLE and compared them with a model of healthy memory encoding (Nenert et al., 2014). For those with LMTLE, we identified and retained for further analyses and model generation 7 ICA task-related components that were attributed to four different networks: the frontal and posterior components of the DMN, visual network, auditory-insular network, and an "other" network. For those with RMTLE, ICA produced 9 task-related components that were attributed to the somatosensory and cerebellar networks in addition to the same networks as in patients with LMTLE. Granger causality analysis revealed group differences in causality relations within the visual memory network and MTLE-related deviations from normal network function. Our results demonstrate differences in the networks for visual memory encoding between those with LMTLE and those with RMTLE. Consistent with previous studies, the organization of memory encoding is dependent on laterality of seizure focus and may be mediated by functional reorganization in chronic epilepsy. These differences may underlie the observed differences in memory abilities between patients with LMTLE and patients with RMTLE and highlight the modulating effects of epilepsy on the network for memory encoding.

  5. Pupil old/new effects reflect stimulus encoding and decoding in short-term memory.

    Science.gov (United States)

    Brocher, Andreas; Graf, Tim

    2016-12-01

    We conducted five pupil old/new experiments to examine whether pupil old/new effects can be linked to familiarity and/or recollection processes of recognition memory. In Experiments 1-3, we elicited robust pupil old/new effects for legal words and pseudowords (Experiment 1), positive and negative words (Experiment 2), and low-frequency and high-frequency words (Experiment 3). Importantly, unlike for old/new effects in ERPs, we failed to find any effects of long-term memory representations on pupil old/new effects. In Experiment 4, using the words and pseudowords from Experiment 1, participants made lexical decisions instead of old/new decisions. Pupil old/new effects were restricted to legal words. Additionally requiring participants to make speeded responses (Experiment 5) led to a complete absence of old/new effects. Taken together, these data suggest that pupil old/new effects do not map onto familiarity and recollection processes of recognition memory. They rather seem to reflect strength of memory traces in short-term memory, with little influence of long-term memory representations. Crucially, weakening the memory trace through manipulations in the experimental task significantly reduces pupil/old new effects.

  6. Emotion effects on implicit and explicit musical memory in normal aging.

    Science.gov (United States)

    Narme, Pauline; Peretz, Isabelle; Strub, Marie-Laure; Ergis, Anne-Marie

    2016-12-01

    Normal aging affects explicit memory while leaving implicit memory relatively spared. Normal aging also modifies how emotions are processed and experienced, with increasing evidence that older adults (OAs) focus more on positive information than younger adults (YAs). The aim of the present study was to investigate how age-related changes in emotion processing influence explicit and implicit memory. We used emotional melodies that differed in terms of valence (positive or negative) and arousal (high or low). Implicit memory was assessed with a preference task exploiting exposure effects, and explicit memory with a recognition task. Results indicated that effects of valence and arousal interacted to modulate both implicit and explicit memory in YAs. In OAs, recognition was poorer than in YAs; however, recognition of positive and high-arousal (happy) studied melodies was comparable. Insofar as socioemotional selectivity theory (SST) predicts a preservation of the recognition of positive information, our findings are not fully consistent with the extension of this theory to positive melodies since recognition of low-arousal (peaceful) studied melodies was poorer in OAs. In the preference task, YAs showed stronger exposure effects than OAs, suggesting an age-related decline of implicit memory. This impairment is smaller than the one observed for explicit memory (recognition), extending to the musical domain the dissociation between explicit memory decline and implicit memory relative preservation in aging. Finally, the disproportionate preference for positive material seen in OAs did not translate into stronger exposure effects for positive material suggesting no age-related emotional bias in implicit memory. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  7. Neurogenic effects of fingolimod in hippocampus, affecting fear memory.

    Directory of Open Access Journals (Sweden)

    Paschalis Efstathopoulos

    2014-05-01

    Full Text Available Fingolimod (FTY720; Gilenya™,Novartis Pharma AG is a recently developed Sphingosine-1-Phosphate (S1P analogue, orally administered as a new therapeutic agent in Multiple Sclerosis (MS (Brinkmann V. et al. 2010. S1P receptors (S1PRs are expressed in various sites in the CNS including the subventricular zone (Waeber C. et al. 1999; Choi J.W. et al. 2013 while endogenous S1P was shown to induce proliferation and morphological changes in embryonic hippocampal neural progenitors in culture (Harada J. et al. 2004. In this study we investigated the effects of fingolimod on adult rodent hippocampal neurogenesis and their possible functional role. To this aim, thymidine analogue BrdU was injected at the end or before a 2-week i.p. administration of a therapeutic dose of Fingolimod (0,3 mg/kg in young and old mice. Stereological counts of BrdU+ cells revealed significant increase in both proliferation, and survival of neural stem cells (NSC in the area of Dentate Gyrus (DG of the hippocampus, compared to control untreated animals of young but not old ages. In the case of survival assessment, most of the BrdU + cells were also positive for NeuN, suggesting an increase of newly formed neurons. The increase in proliferation rate of NSC was also confirmed by BrdU uptake in hippocampal NSC cultures in vitro, implying that the effects of fingolimod are cell autonomous. Immunohistochemical analysis showed that S1PR was not co-localized with GFAP+ cells in the Subgranular zone (SGZ of the DG, but was strongly co-localized with transcription factor MASH1 and weakly with DcX or PSA-NCAM positive neural progenitors. These findings suggest that expression of S1PR1 in the SGZ is restricted to transit amplifying neural progenitors and maintained also in the stage of neuroblast. In addition, the effects of Fingolimod in DG neurogenesis were positively correlated to enhanced fear memory and increased context discrimination, an established DG-dependent cognitive task

  8. Relationship among grain size, annealing twins and shape memory effect in Fe-Mn-Si based shape memory alloys

    Science.gov (United States)

    Wang, Gaixia; Peng, Huabei; Zhang, Chengyan; Wang, Shanling; Wen, Yuhua

    2016-07-01

    In order to clarify the relationship among grain size, annealing twins and the shape memory effect in Fe-Mn-Si based shape memory alloys, the Fe-21.63Mn-5.60Si-9.32Cr-5.38Ni (weight %) alloy with a grain size ranging from 48.9 μm-253.6 μm was obtained by adjusting the heating temperature or heating time after 20% cold-rolling. The densities of grain boundaries and annealing twins increase with a decrease in grain size, whereas the volume fraction and width of stress-induced ɛ martensite after 9% deformation at Ms + 10 K decrease. This result indicates that grain refinement raises the constraint effects of grain boundaries and annealing twins upon martensitic transformation. In this case, the ability to suppress the plastic deformation and facilitate the stress-induced ɛ martensite transformation deteriorates after grain refinement owing to the enhancement of the constraint effects. It is demonstrated by the result that the difference at Ms + 10 K between the critical stress for plastic yielding and that for inducing martensitic transformation is smaller for the specimen with a grain size of 48.9 μm than for the specimen with a grain size of 253.6 μm. Therefore, the shape memory effect declined by decreasing the grain size.

  9. Multimedia Learning and Individual Differences: Mediating the Effects of Working Memory Capacity with Segmentation

    Science.gov (United States)

    Lusk, Danielle L.; Evans, Amber D.; Jeffrey, Thomas R.; Palmer, Keith R.; Wikstrom, Chris S.; Doolittle, Peter E.

    2009-01-01

    Research in multimedia learning lacks an emphasis on individual difference variables, such as working memory capacity (WMC). The effects of WMC and the segmentation of multimedia instruction were examined by assessing the recall and application of low (n = 66) and high (n = 67) working memory capacity students randomly assigned to either a…

  10. Does Bilingualism Help Memory? Competing Effects of Verbal Ability and Executive Control

    Science.gov (United States)

    Wodniecka, Zofia; Craik, Fergus I. M.; Luo, Lin; Bialystok, Ellen

    2010-01-01

    Two studies are reported that explore the effect of bilingualism on memory performance. Following previous reports of a bilingual advantage in executive control that sometimes shows a greater advantage in older adults, we compared younger and older monolinguals and bilinguals on a memory paradigm that yielded separate measures of familiarity and…

  11. Serial position effects scoring in the assessment of memory in Alzheimer's disease and major depression

    NARCIS (Netherlands)

    Bemelmans, Karel Jozef

    2009-01-01

    The objective of this thesis was to validate serial position effects (SPE’S) scoring in the Rey Auditory Verbal Learning Test (RAVLT). The RAVLT is a much used clinical method for assessing memory performance, but the method of scoring obfuscates that two memory processes underlie free recall. This

  12. Emotion-Memory Effects in Bilingual Speakers: A Levels-of-Close Processing Approach

    Science.gov (United States)

    Aycicegi-Dinn, Ayse; Caldwell-Harris, Catherine L.

    2009-01-01

    Emotion-memory effects occur when emotion words are more frequently recalled than neutral words. Bilingual speakers report that taboo terms and emotional phrases generate a stronger emotional response when heard or spoken in their first language. This suggests that the basic emotion-memory will be stronger for words presented in a first language.…

  13. Working Memory Effects in the L2 Processing of Ambiguous Relative Clauses

    Science.gov (United States)

    Hopp, Holger

    2014-01-01

    This article investigates whether and how L2 sentence processing is affected by memory constraints that force serial parsing. Monitoring eye movements, we test effects of working memory on L2 relative-clause attachment preferences in a sample of 75 late-adult German learners of English and 25 native English controls. Mixed linear regression…

  14. The Effects of Presentation Method and Information Density on Visual Search Ability and Working Memory Load

    Science.gov (United States)

    Chang, Ting-Wen; Kinshuk; Chen, Nian-Shing; Yu, Pao-Ta

    2012-01-01

    This study investigates the effects of successive and simultaneous information presentation methods on learner's visual search ability and working memory load for different information densities. Since the processing of information in the brain depends on the capacity of visual short-term memory (VSTM), the limited information processing capacity…

  15. Comparative Effect of Memory and Cognitive Strategies Training on EFL Intermediate Learners' Vocabulary Learning

    Science.gov (United States)

    Banisaeid, Maryam

    2013-01-01

    The present study was conducted to compare the effect of memory and cognitive strategies training on vocabulary learning of intermediate proficiency group of Iranian learners of English as a foreign language. It is to check how memory and cognitive strategies training affect word learning of EFL intermediate learners (N = 60) who were homogenized…

  16. The effects of Anethum graveolens essence on scopolamine-induced memory impairment in mice

    Directory of Open Access Journals (Sweden)

    Azadeh Mesripour

    2016-01-01

    Full Text Available Since Anethum graveolens (Dill has phytoestrogenic compounds and it is proven that estrogens exert beneficial effects on cognition; the aim of this study was to understand if this plant can improve memory performance. Male Balb/c mice weighing 25-30 g were used in this study and memory was assessed by the novel object recognition task. In this method, the difference in the exploration time between a familiar object and a novel object is taken as an index of memory performance (recognition index, RI. Scopolamine significantly reduced memory index (RI = -15.5% ± 3.0. Dill essence (100 mg/kg, ip prevented the harmful effects of scopolamine on memory (RI = 40% ± 5.5, thus RI did not differ with control animals (RI = 50% ± 5.8. In addition, 17-β estradiol also prevented memory impairment in animals (0.2 mg/kg, ip; RI = 35.8% ± 6.5. Nevertheless, the beneficial effects of dill essence were antagonized by prior injection of tamoxifen (1 mg/kg, ip; RI = -30% ± 7.8. Although phytoesrogens are not steroids, the beneficial effect of dill on memory, at least in part, may have been achieved by estrogenic receptors present in the brain. Thus dill essence could be promising in improving memory and cognition, mainly in postmenopausal women.

  17. Serial position effects scoring in the assessment of memory in Alzheimer's disease and major depression

    NARCIS (Netherlands)

    Bemelmans, Karel Jozef

    2009-01-01

    The objective of this thesis was to validate serial position effects (SPE’S) scoring in the Rey Auditory Verbal Learning Test (RAVLT). The RAVLT is a much used clinical method for assessing memory performance, but the method of scoring obfuscates that two memory processes underlie free recall. This

  18. Effects of Saccadic Bilateral Eye Movements on Memory in Children and Adults: An Exploratory Study

    Science.gov (United States)

    Parker, Andrew; Dagnall, Neil

    2012-01-01

    The effects of saccadic bilateral (horizontal) eye movements on true and false memory in adults and children were investigated. Both adults and children encoded lists of associated words in the Deese-Roediger-McDermott paradigm followed by a test of recognition memory. Just prior to retrieval, participants were asked to engage in 30 s of bilateral…

  19. Emotion-Memory Effects in Bilingual Speakers: A Levels-of-Close Processing Approach

    Science.gov (United States)

    Aycicegi-Dinn, Ayse; Caldwell-Harris, Catherine L.

    2009-01-01

    Emotion-memory effects occur when emotion words are more frequently recalled than neutral words. Bilingual speakers report that taboo terms and emotional phrases generate a stronger emotional response when heard or spoken in their first language. This suggests that the basic emotion-memory will be stronger for words presented in a first language.…

  20. Integrating Piano Keyboarding into the Elementary Classroom: Effects on Memory Skills and Sentiment Toward School.

    Science.gov (United States)

    Marcinkiewicz, Henryk R.; And Others

    1995-01-01

    Discovered that the introduction of piano keyboarding into elementary school music instruction produced a positive effect regarding children's sentiment towards school. No discernible effect was revealed concerning memory skills. Includes statistical data and description of survey questionnaires. (MJP)

  1. Effect of Prunus domestica L. (mirabelle on learning and memory in mice

    Directory of Open Access Journals (Sweden)

    Siamak Shahidi

    2013-01-01

    Conclusions: Hydro-alcoholic extract of plum has a beneficial effect on learning and memory in passive avoidance task. It can be concluded that its antioxidant and antidyslipidemic activities may be involved in the obtained effects.

  2. ROLE OF THE ENDOCANNABINOID SYSTEM IN REGULATING GLUCOCORTICOID EFFECTS ON MEMORY FOR EMOTIONAL EXPERIENCES

    NARCIS (Netherlands)

    Atsak, P.; Roozendaal, B.; Campolongo, P.

    2012-01-01

    Glucocorticoids, stress hormones released from the adrenal cortex, have potent modulatory effects on emotional memory. Whereas early studies focused mostly on the detrimental effects of chronic stress and glucocorticoid exposure on cognitive performance and the classic genomic pathways that mediate

  3. Does Controlling for Temporal Parameters Change the Levels-of-Processing Effect in Working Memory?

    OpenAIRE

    Loaiza, Vanessa M.; Camos, Val?rie

    2016-01-01

    The distinguishability between working memory (WM) and long-term memory has been a frequent and long-lasting source of debate in the literature. One recent method of identifying the relationship between the two systems has been to consider the influence of long-term memory effects, such as the levels-of-processing (LoP) effect, in WM. However, the few studies that have examined the LoP effect in WM have shown divergent results. This study examined the LoP effect in WM by considering a theoret...

  4. Aging and memory effect in magnetoelectric gallium ferrite single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Vijay; Mukherjee, Somdutta [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Mitra, Chiranjib [Department of Physics, Indian Institute of Science Education and Research, Kolkata 741252 (India); Garg, Ashish [Department of Materials Science and Engineering, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Gupta, Rajeev, E-mail: guptaraj@iitk.ac.in [Department of Physics, Indian Institute of Technology Kanpur, Kanpur 208016 (India); Materials Science Programme, Indian Institute of Technology Kanpur, Kanpur 208016 (India)

    2015-02-01

    Here, we present a time and temperature dependent magnetization study to understand the spin dynamics in flux grown single crystals of gallium ferrite (GaFeO{sub 3}), a known magnetoelectric, ferroelectric and ferrimagnet. Results of the magnetic measurements conducted in the field-cooled (FC) and zero-field-cooled (ZFC) protocols in the heating and cooling cycles were reminiscent of a “memory” effect. Subsequent time dependent magnetic relaxation measurements carried out in ZFC mode at 30 K with an intermittent cooling to 20 K in the presence of a small field show that the magnetization in the final wait period tends to follow its initial state which was present before the cooling break taken at 20 K. These observations provide an unambiguous evidence of single crystal gallium ferrite having a spin glass like phase. - Highlights: • Gallium ferrite a room temperature magnetoelectric and ferrimagnetic material. • Spin‐glass like phase at low temperatures below ∼200 K. • Observation of memory and aging effects in GFO.

  5. Memory Saves Lives: Inter-generational Warnings Effectiveness - 13556

    Energy Technology Data Exchange (ETDEWEB)

    Van Luik, Abraham; Patterson, Russell [U.S. Department of Energy, Carlsbad Field Office, 4021 S. National Parks Highway, Carlsbad, NM 88220 (United States); Shafer, David [U.S. Department of Energy, Office of Legacy Management, 11025 Dover Street, Suite 1000, Westminster, CO 80021 (United States); Klein, Thomas [URS Regulatory and Environmental Services, 4021 S. National Parks Highway, Carlsbad, NM 88220 (United States)

    2013-07-01

    The 2011 Tohoku earthquake and tsunami was a world-class natural disaster. It has been described as the most powerful earthquake ever in Japan, and as one of the most powerful earthquakes ever noted in the world. The toll in terms of human lives lost and property destruction was unimaginable. Even the word 'horrible' is inadequate to describe the suffering and misery that resulted. Nations with nuclear power programs are engaged in, or at least planning to become engaged in, arranging to eventually dispose of their higher-level radioactive waste materials in deep geologic repositories. Geologic repositories are passive safety systems, and if undisturbed isolate these dangerous materials form the biosphere for extremely long times. The key words, however, are 'if undisturbed'. To assure that future generations do not inadvertently drill into repositories, national programs, and the international community (the Records, Knowledge and Memory (RK and M) preservation project of the Nuclear Energy Agency, for example), are proposing to place markers and/or monuments on closed repository sites that say 'do not drill here, and this is why' in various sophisticated ways. Such markers or monuments are attempts at providing passive institutional controls. The effectiveness of messages from past generations to a present generation may give an indication of how effective such passive institutional controls may be. (authors)

  6. Effects of intrinsic and extrinsic motivation on attention and memory.

    Science.gov (United States)

    Robinson, Lucy J; Stevens, Lucy H; Threapleton, Christopher J D; Vainiute, Jurgita; McAllister-Williams, R Hamish; Gallagher, Peter

    2012-10-01

    It is well recognised that motivational factors can influence neuropsychological performance. The aim of this study was to explore individual differences in intrinsic motivation and reward-seeking and the effect of these on attentional and mnemonic processes, in the presence or absence of financial incentives. Forty participants (18-35years) completed two testing sessions where the Attentional Network Test (ANT) and the Newcastle Spatial Memory Test (NSMT) were administered. After a baseline assessment, participants were re-tested after randomisation to a non-motivated (control) group or to a motivated group, where payment was contingent upon performance. Performance in the motivated group was significantly improved compared to the control group on the NSMT (condition by session; F(1,33)=4.52, p=0.041) and the ANT, with participants increasing performance to cued presentations within the alerting network (F(1,36)=5.48, p=0.025) and being less distracted by incongruent stimuli in the executive control network (F(1,36)=6.74, p=0.014). There were significant negative correlations between the 'Interest/ Enjoyment' Intrinsic Motivation Inventory subscale and both NSMT between-search errors and ANT(alerting). In the motivated group, those who had higher self-reported internal motivation were less susceptible to- or affected by- the external motivation of financial incentive. The effects of motivational factors should not be overlooked when interpreting absolute levels of performance in neuropsychological processes. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Two- way Shape Memory Effect in a Ti-Ni-Nb Shape Memory Alloy with Wide Hysteresis

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A two-way shape memory effect (TWSME) in the Ti46.3Ni44.7Nb9 alloy has been systematically investigated by means of bending test and transmission electron microscopy (TEM) observations. Based on the analysis of the microstructure after training, the mechanism of TWSME in the Ti46.3Ni44.7Nb9 alloy has been discussed.

  8. The effects of acute stress on episodic memory: A meta-analysis and integrative review.

    Science.gov (United States)

    Shields, Grant S; Sazma, Matthew A; McCullough, Andrew M; Yonelinas, Andrew P

    2017-06-01

    A growing body of research has indicated that acute stress can critically impact memory. However, there are a number of inconsistencies in the literature, and important questions remain regarding the conditions under which stress effects emerge as well as basic questions about how stress impacts different phases of memory. In this meta-analysis, we examined 113 independent studies in humans with 6,216 participants that explored effects of stress on encoding, postencoding, retrieval, or postreactivation phases of episodic memory. The results indicated that when stress occurred prior to or during encoding it impaired memory, unless both the delay between the stressor and encoding was very short and the study materials were directly related to the stressor, in which case stress improved encoding. In contrast, postencoding stress improved memory unless the stressor occurred in a different physical context than the study materials. When stress occurred just prior to or during retrieval, memory was impaired, and these effects were larger for emotionally valenced materials than neutral materials. Although stress consistently increased cortisol, the magnitude of the cortisol response was not related to the effects of stress on memory. Nonetheless, the effects of stress on memory were generally reduced in magnitude for women taking hormonal contraceptives. These analyses indicate that stress disrupts some episodic memory processes while enhancing others, and that the effects of stress are modulated by a number of critical factors. These results provide important constraints on current theories of stress and memory, and point to new questions for future research. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

  9. Memory efficient atmospheric effects modeling for infrared scene generators

    Science.gov (United States)

    Kavak, Çaǧlar; Özsaraç, Seçkin

    2015-05-01

    The infrared (IR) energy radiated from any source passes through the atmosphere before reaching the sensor. As a result, the total signature captured by the IR sensor is significantly modified by the atmospheric effects. The dominant physical quantities that constitute the mentioned atmospheric effects are the atmospheric transmittance and the atmospheric path radiance. The incoming IR radiation is attenuated by the transmittance and path radiance is added on top of the attenuated radiation. In IR scene simulations OpenGL is widely used for rendering purposes. In the literature there are studies, which model the atmospheric effects in an IR band using OpenGLs exponential fog model as suggested by Beers law. In the standard pipeline of OpenGL, the related fog model needs single equivalent OpenGL variables for the transmittance and path radiance, which actually depend on both the distance between the source and the sensor and also on the wavelength of interest. However, in the conditions where the range dependency cannot be modeled as an exponential function, it is not accurate to replace the atmospheric quantities with a single parameter. The introduction of OpenGL Shading Language (GLSL) has enabled the developers to use the GPU more flexible. In this paper, a novel method is proposed for the atmospheric effects modeling using the least squares estimation with polynomial fitting by programmable OpenGL shader programs built with GLSL. In this context, a radiative transfer model code is used to obtain the transmittance and path radiance data. Then, polynomial fits are computed for the range dependency of these variables. Hence, the atmospheric effects model data that will be uploaded in the GPU memory is significantly reduced. Moreover, the error because of fitting is negligible as long as narrow IR bands are used.

  10. The effect of memory on relaxation in a scalar field theory

    CERN Document Server

    Ikeda, T

    2004-01-01

    We derive a kinetic equation with a non-Markovian collision term which includes a memory effect, from Kadanoff-Baym equations in $\\phi^4$ theory within the three-loop level for the two-particle irreducible (2PI) effective action. The memory effect is incorporated into the kinetic equation by a generalized Kadanoff-Baym ansatz.Based on the kinetic equations with and without the memory effect, we investigate an influence of this effect on decay of a single particle excitation with zero momentum in 3+1 dimensions and the spatially homogeneous case. Numerical results show that, while the time evolution of the zero mode is completely unaffected by the memory effect due to a separation of scales in the weak coupling regime, this effect leads first to faster relaxation than the case without it and then to slower relaxation as the coupling constant increases.

  11. Time-limited effects of emotional arousal on item and source memory.

    Science.gov (United States)

    Wang, Bo; Sun, Bukuan

    2015-01-01

    Two experiments investigated the time-limited effects of emotional arousal on consolidation of item and source memory. In Experiment 1, participants memorized words (items) and the corresponding speakers (sources) and then took an immediate free recall test. Then they watched a neutral, positive, or negative video 5, 35, or 50 min after learning, and 24 hours later they took surprise memory tests. Experiment 2 was similar to Experiment 1 except that (a) a reality monitoring task was used; (b) elicitation delays of 5, 30, and 45 min were used; and (c) delayed memory tests were given 60 min after learning. Both experiments showed that, regardless of elicitation delay, emotional arousal did not enhance item recall memory. Second, both experiments showed that negative arousal enhanced delayed item recognition memory only at the medium elicitation delay, but not in the shorter or longer delays. Positive arousal enhanced performance only in Experiment 1. Third, regardless of elicitation delay, emotional arousal had little effect on source memory. These findings have implications for theories of emotion and memory, suggesting that emotion effects are contingent upon the nature of the memory task and elicitation delay.

  12. Involvement of basolateral amygdala GABAA receptors in the effect of dexamethasone on memory in rats

    Institute of Scientific and Technical Information of China (English)

    Lotfollah KHAJEHPOUR; Acieh ALIZADEH-MAKVANDI; Mahnaz KESMATI; Hooman ESHAGH-HAROONI

    2011-01-01

    In this study we investigated whether GABAA receptors of the basolateral amygdala (BLA) interact with the effect of dexamethasone on the retrieval stage of memory.Adult male Wistar rats were bilaterally cannulated in the BLA by stereotaxic surgery.The animals were trained in step-through apparatus by induction of electric shock (1.5 mA,3 s) and were tested for memory retrieval after 1 d.The time of latency for entering the dark compartment of the instrument and the time spent by rats in this chamber were recorded for evaluation of the animals' retrieval in passive avoidance memory.Administration of dexamethasone (0.3 and 0.9 mg/kg,subcutaneously (s.c.)),immediately after training,enhanced memory retrieval.This effect was reduced by intra-BLA microinjection of muscimol (0.125,0.250 and 0.500 μg/rat),when administered before 0.9 mg/kg of dexamethasone.Microinjection of bicuculline (0.75 μg/rat,intra-BLA) with an ineffective dose of dexamethasone (0.1 mg/kg,s.c.) increased memory retrieval.However,the same doses of muscimol and bicuculline without dexamethasone did not affect memory processes.Our data support reports that dexamethasone enhances memory retrieval.It seems that GABAA receptors of the BLA mediate the effect of dexamethasone on memory retrieval in rats.

  13. Effects of Working Memory Capacity and Domain Knowledge on Recall for Grocery Prices.

    Science.gov (United States)

    Bermingham, Douglas; Gardner, Michael K; Woltz, Dan J

    2016-01-01

    Hambrick and Engle (2002) proposed 3 models of how domain knowledge and working memory capacity may work together to influence episodic memory: a "rich-get-richer" model, a "building blocks" model, and a "compensatory" model. Their results supported the rich-get-richer model, although later work by Hambrick and Oswald (2005) found support for a building blocks model. We investigated the effects of domain knowledge and working memory on recall of studied grocery prices. Working memory was measured with 3 simple span tasks. A contrast of realistic versus fictitious foods in the episodic memory task served as our manipulation of domain knowledge, because participants could not have domain knowledge of fictitious food prices. There was a strong effect for domain knowledge (realistic food-price pairs were easier to remember) and a moderate effect for working memory capacity (higher working memory capacity produced better recall). Furthermore, the interaction between domain knowledge and working memory produced a small but significant interaction in 1 measure of price recall. This supported the compensatory model and stands in contrast to previous research.

  14. Brain Imaging Investigation of the Memory-Enhancing Effect of Emotion

    Science.gov (United States)

    Shafer, Andrea; Iordan, Alexandru; Cabeza, Roberto; Dolcos, Florin

    2011-01-01

    Emotional events tend to be better remembered than non-emotional events1,2. One goal of cognitive and affective neuroscientists is to understand the neural mechanisms underlying this enhancing effect of emotion on memory. A method that has proven particularly influential in the investigation of the memory-enhancing effect of emotion is the so-called subsequent memory paradigm (SMP). This method was originally used to investigate the neural correlates of non-emotional memories3, and more recently we and others also applied it successfully to studies of emotional memory (reviewed in4, 5-7). Here, we describe a protocol that allows investigation of the neural correlates of the memory-enhancing effect of emotion using the SMP in conjunction with event-related functional magnetic resonance imaging (fMRI). An important feature of the SMP is that it allows separation of brain activity specifically associated with memory from more general activity associated with perception. Moreover, in the context of investigating the impact of emotional stimuli, SMP allows identification of brain regions whose activity is susceptible to emotional modulation of both general/perceptual and memory-specific processing. This protocol can be used in healthy subjects8-15, as well as in clinical patients where there are alterations in the neural correlates of emotion perception and biases in remembering emotional events, such as those suffering from depression and post-traumatic stress disorder (PTSD)16, 17. PMID:21587158

  15. Effect of yogic education system and modern education system on memory

    Directory of Open Access Journals (Sweden)

    Rangan R

    2009-01-01

    Full Text Available Background/Aim: Memory is more associated with the temporal cortex than other cortical areas. The two main components of memory are spatial and verbal which relate to right and left hemispheres of the brain, respectively. Many investigations have shown the beneficial effects of yoga on memory and temporal functions of the brain. This study was aimed at comparing the effect of one Gurukula Education System (GES school based on a yoga way of life with a school using the Modern Education System (MES on memory. Materials and Methods: Forty nine boys of ages ranging from 11-13 years were selected from each of two residential schools, one MES and the other GES, providing similar ambiance and daily routines. The boys were matched for age and socioeconomic status. The GES educational program is based around integrated yoga modules while the MES provides a conventional modern education program. Memory was assessed by means of standard spatial and verbal memory tests applicable to Indian conditions before and after an academic year. Results: Between groups there was matching at start of the academic year, while after it the GES boys showed significant enhancement in both verbal and visual memory scores than MES boys (P < 0.001, Mann-Whitney test. Conclusions: The present study showed that the GES meant for total personality development adopting yoga way of life is more effective in enhancing visual and verbal memory scores than the MES.

  16. Limited Near and Far Transfer Effects of Jungle Memory Working Memory Training on Learning Mathematics in Children with Attentional and Mathematical Difficulties

    Science.gov (United States)

    Nelwan, Michel; Kroesbergen, Evelyn H.

    2016-01-01

    The goal of this randomized controlled trial was to investigate whether Jungle Memory working memory training (JM) affects performance on working memory tasks, performance in mathematics and gains made on a mathematics training (MT) in school aged children between 9–12 years old (N = 64) with both difficulties in mathematics, as well as attention and working memory. Children were randomly assigned to three groups and were trained in two periods: (1) JM first, followed by MT, (2) MT first, followed by JM, and (3) a control group that received MT only. Bayesian analyses showed possible short term effects of JM on near transfer measures of verbal working memory, but none on visual working memory. Furthermore, support was found for the hypothesis that children that received JM first, performed better after MT than children who did not follow JM first or did not train with JM at all. However, these effects could be explained at least partly by frequency of training effects, possibly due to motivational issues, and training-specific factors. Furthermore, it remains unclear whether the effects found on improving mathematics were actually mediated by gains in working memory. It is argued that JM might not train the components of working memory involved in mathematics sufficiently. Another possible explanation can be found in the training’s lack of adaptivity, therefore failing to provide the children with tailored instruction and feedback. Finally, it was hypothesized that, since effect sizes are generally small, training effects are bound to a critical period in development. PMID:27708595

  17. On the weakly(α, ψ, ξ-contractive condition for multi-valued operators in metric spaces and related fixed point results

    Directory of Open Access Journals (Sweden)

    Kutbi Marwan Amin

    2016-01-01

    Full Text Available The aim of this paper is to introduce the concept of a new nonlinear multi-valued mapping so called weakly (α, ψ, ξ-contractive mapping and prove fixed point results for such mappings in metric spaces. Our results unify, generalize and complement various results from the literature. We give some examples which support our main results while previous results in literature are not applicable. Also, we analyze the existence of fixed points for mappings satisfying a general contractive inequality of integral type. Many fixed point results for multi-valued mappings in metric spaces endowed with an arbitrary binary relation and metric spaces endowed with graph are given here to illustrate the results in this paper.

  18. Memory Facilitation effect in Interaction between Video Clips and Music

    OpenAIRE

    吉岡, 賢治; 岩永, 誠

    2007-01-01

    Previous studies examined memories of video clips under the condition of affects combination of pictures and music. Video clips, which were combined with music in same impressions, were easy to remember their contents. The present study aimed to examine the memory facilitation about pictures in two perspectives, the strength of affects and the distribution of the processing recourses. Participants were 39 undergraduate volunteers, who were divided into three experimental conditions randomly. ...

  19. The effect of acute stress on memory depends on word valence.

    Science.gov (United States)

    Smeets, Tom; Jelicic, Marko; Merckelbach, Harald

    2006-10-01

    The present study investigated the effect of acute stress on working memory and memory for neutral, emotionally negative, and emotionally positive words in healthy undergraduates. Participants (N=60) were exposed to either the Trier Social Stress Test (stress group) or a non-stressful task (control group). Analyses of salivary cortisol samples taken throughout the study showed elevated glucocorticoid levels after the experimental manipulation in the stress group, but not in the control group. Recall performance was impaired in the stress group, but only so for neutral words. No differences between the stress and control group were found on working memory measures. For the stress group, digit span forward and digit span total scores were associated with correct recall of neutral words. All in all, this study lends further support to the notion that the memory effects of exposure to acute stress depend on the valence of the memory material.

  20. Intrinsic memory function of carbon nanotube-based ferroelectric field-effect transistor.

    Science.gov (United States)

    Fu, Wangyang; Xu, Zhi; Bai, Xuedong; Gu, Changzhi; Wang, Enge

    2009-03-01

    We demonstrate the intrinsic memory function of ferroelectric field-effect transistors (FeFETs) based on an integration of individual single-walled carbon nanotubes (SWCNTs) and epitaxial ferroelectric films. In contrast to the previously reported "charge-storage" CNT-FET memories, whose operations are haunted by a lack of control over the "charge traps", the present CNT-FeFETs exhibit a well-defined memory hysteresis loop induced by the reversible remnant polarization of the ferroelectric films. Large memory windows approximately 4 V, data retention time up to 1 week, and ultralow power consumption (energy per bit) of femto-joule, are highlighted in this report. Further simulations and experimental results show that the memory device is valid under operation voltage less than 1 V due to an electric-field enhancement effect induced by the ultrathin SWCNTs.

  1. [The effect of impression formation on memory of trait words: relation between coding and retrieval process].

    Science.gov (United States)

    Takaoka, M

    2000-08-01

    Three experiments investigated the effect of impression formation of a person on the recall and recognition of trait words. The subjects were assigned to one of four groups: Impression, Memory, Impression-Memory, and Incidental groups. Each subject performed an orienting task followed by free recall and recognition tests. In a recall test, false recall of antonyms of targets occurred more often in the Memory group than in the Impression group. There was no difference in the correct recall. In a multiple choice recognition test and a yes-no recognition test, false recognition to antonyms of targets occurred more often in the Memory group than in the Impression group. Hit to targets occurred more often in the Impression group than in the Memory group. These results were interpreted as showing that formation of an impression for a person had different effects for recall and recognition tests. The results were discussed in terms of a relation between encoding and retrieval processes.

  2. The effect of hormone replacement therapy on mood and everyday memory in younger mid-life women.

    Science.gov (United States)

    Stephens, Christine; Pachana, Nancy A; Bristow, Virginia

    2006-11-01

    Research on the effect of hormone replacement therapy (HRT) on both mood and memory indicates that oestrogen may enhance verbal memory in younger mid-aged women. This study examined the effect of HRT on everyday memory, while accounting for mood changes, in women between ages 40 and 60. A within-subjects comparison of 17 women, showed that mood, everyday memory, working memory, and delayed verbal memory improved after 3 months of HRT use. The improvement in memory was not mediated by mood, but changes in mood were moderated by exercise habits. The results suggest that verbal memory in particular may be enhanced by HRT in this age group, and everyday memory is an important construct to consider in future research.

  3. Organic field-effect transistor nonvolatile memories utilizing sputtered C nanoparticles as nano-floating-gate

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jie; Liu, Chang-Hai; She, Xiao-Jian; Sun, Qi-Jun; Gao, Xu; Wang, Sui-Dong, E-mail: wangsd@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM), Soochow University, Suzhou, Jiangsu 215123 (China)

    2014-10-20

    High-performance organic field-effect transistor nonvolatile memories have been achieved using sputtered C nanoparticles as the nano-floating-gate. The sputtered C nano-floating-gate is prepared with low-cost material and simple process, forming uniform and discrete charge trapping sites covered by a smooth and complete polystyrene layer. The devices show large memory window, excellent retention capability, and programming/reading/erasing/reading endurance. The sputtered C nano-floating-gate can effectively trap both holes and electrons, and it is demonstrated to be suitable for not only p-type but also n-type organic field-effect transistor nonvolatile memories.

  4. Effects of histamine on MK-801-induced memory deficits in radial maze performance in rats.

    Science.gov (United States)

    Chen, Z; Zhao, Q; Sugimoto, Y; Fujii, Y; Kamei, C

    1999-08-21

    The effects of histamine on the spatial memory deficits induced by MK-801 were investigated using the eight-arm radial maze paradigm in rats. Intracerebroventricular (i.c.v.) injection of histamine or thioperamide, and intraperitoneal (i.p.) injection of histidine improved the spatial memory deficits induced by MK-801. Similar results were obtained with 2-thiazolylethylamine. In contrast, 4-methylhistamine showed no significant effect. Based on these observations, it seems likely that the protective effect of histamine on MK-801-induced spatial memory deficit is mediated by H(1)-receptors.

  5. The effect of subacute supplementation of taurine on spatial learning and memory.

    Science.gov (United States)

    Ito, Koichi; Arko, Matevz; Kawaguchi, Tomohiro; Kuwahara, Masayoshi; Tsubone, Hirokazu

    2009-04-01

    Although the effect of taurine on the heart and liver is well studied, there has been no direct observation concerning the effect of taurine on spatial learning and memory at the behavior level. In this study, we tested the effect of subacute taurine supplementation with evaluation by the Morris water maze method. Although swim distance to find the platform of taurine-supplemented rats was significantly longer than that of control rats due to increase of swimming velocity, escape latency and the efficacy of learning and memory was comparable in both groups. These results suggest that taurine supplemented orally does not affect the learning and memory function.

  6. Sex differences in HIV effects on visual memory among substance-dependent individuals.

    Science.gov (United States)

    Keutmann, Michael K; Gonzalez, Raul; Maki, Pauline M; Rubin, Leah H; Vassileva, Jasmin; Martin, Eileen M

    2016-11-13

    HIV's effects on episodic memory have not been compared systematically between male and female substance-dependent individuals. We administered the Brief Visuospatial Memory Test-Revised (BVMT-R) to 280 substance-dependent HIV+ and HIV- men and women. Groups were comparable on demographic, substance use, and comorbid characteristics. There were no significant main effects of sex or HIV serostatus on BVMT-R performance, but HIV+ women performed significantly more poorly on delayed recall. This effect was most prominent among cocaine-dependent HIV+ women. Our findings are consistent with recent speculation that memory impairment may be more common among HIV+ women, particularly those with a history of cocaine dependence.

  7. Volterra series based predistortion for broadband RF power amplifiers with memory effects

    Institute of Scientific and Technical Information of China (English)

    Jin Zhe; Song Zhihuan; He Jiaming

    2008-01-01

    RF power amplifiers(PAs)are usually considered as memoryless devices in most existing predistortion techniques.However,in broadband communication systems,such as WCDMA,the PA memory effects are significant,and memoryless predistortion cannot linearize the PAs effectively.After analyzing the PA memory effects,a novel predistortion method based on the simplified Volterra series is proposed to linearize broadband RF PAs with memory effects.The indirect learning architecture is adopted to design the predistortion scheme and the recursive least squares algorithm with forgetting factor is applied to identify the parameters of the predistorter.Simulation results show that the proposed predistortion method can compensate the nonlinear distortion and memory effects of broadband RF PAs effectively.

  8. Fast-Response-Time Shape-Memory-Effect Foam Actuators

    Science.gov (United States)

    Jardine, Peter

    2010-01-01

    Bulk shape memory alloys, such as Nitinol or CuAlZn, display strong recovery forces undergoing a phase transformation after being strained in their martensitic state. These recovery forces are used for actuation. As the phase transformation is thermally driven, the response time of the actuation can be slow, as the heat must be passively inserted or removed from the alloy. Shape memory alloy TiNi torque tubes have been investigated for at least 20 years and have demonstrated high actuation forces [3,000 in.-lb (approximately equal to 340 N-m) torques] and are very lightweight. However, they are not easy to attach to existing structures. Adhesives will fail in shear at low-torque loads and the TiNi is not weldable, so that mechanical crimp fits have been generally used. These are not reliable, especially in vibratory environments. The TiNi is also slow to heat up, as it can only be heated indirectly using heater and cooling must be done passively. This has restricted their use to on-off actuators where cycle times of approximately one minute is acceptable. Self-propagating high-temperature synthesis (SHS) has been used in the past to make porous TiNi metal foams. Shape Change Technologies has been able to train SHS derived TiNi to exhibit the shape memory effect. As it is an open-celled material, fast response times were observed when the material was heated using hot and cold fluids. A methodology was developed to make the open-celled porous TiNi foams as a tube with integrated hexagonal ends, which then becomes a torsional actuator with fast response times. Under processing developed independently, researchers were able to verify torques of 84 in.-lb (approximately equal to 9.5 Nm) using an actuator weighing 1.3 oz (approximately equal to 37 g) with very fast (less than 1/16th of a second) initial response times when hot and cold fluids were used to facilitate heat transfer. Integrated structural connections were added as part of the net shape process, eliminating

  9. Retarded Fields of Null Particles and the Memory Effect

    CERN Document Server

    Tolish, Alexander

    2014-01-01

    We consider the retarded solution to the scalar, electromagnetic, and linearized gravitational field equations in Minkowski spacetime, with source given by a particle moving on a null geodesic. In the scalar case and in the Lorenz gauge in the electromagnetic and gravitational cases, the retarded integral over the infinite past of the source does not converge as a distribution, so we cut off the null source suitably at a finite time $t_0$ and then consider two different limits: (i) the limit as the observation point goes to null infinity at fixed $t_0$, from which the ``$1/r$'' part of the fields can be extracted and (ii) the limit $t_0 \\to - \\infty$ at fixed ``observation point.'' The limit (i) gives rise to a ``velocity kick'' on distant test particles in the scalar and electromagnetic cases, and it gives rise to a ``memory effect'' (i.e., a permanent change in relative separation of two test particles) in the linearized gravitational case, in agreement with previous analyses. Although the second limit does...

  10. [The effect of working memory on learning from texts].

    Science.gov (United States)

    Abe, Yoshinobu; Kawasaki, Eriko

    2011-08-01

    This study examined the effect of working memory on learning from texts. In Experiment 1, participants preformed a word clustering task involving key words from an explanatory text (pretest), and then read the text, which was presented sentence-by-sentence. Next, they performed a second clustering task (post-test), a problem solving task, and a reading span test (RST). The results suggested that the individual differences of the RST scores correlated with the scores for problem solving. In Experiment 2, the results suggested that the individual differences of the RST scores influenced the clustering performance at the level of the situation model when the text was presented all together. Moreover, the result of multiple dimension scaling suggested that the situation models of high-span readers reflected the structure of the text more than those of low-span readers. These results indicate that readers with high reading span scores construct coherent situation models of texts and make use of them for learning from texts.

  11. Simulation for memory effect of Fick’s first law

    Indian Academy of Sciences (India)

    Koichi Aoki

    2009-09-01

    The memory effect of the Fick’s first law, expressed by ( / ) = - - Dgradc, was confirmed by means of the 3D Monte Carlo simulation, where is the relaxation time, is the flux of the diffusing particles, is the diffusion coefficient, and is the concentration of the particles. The delay has been observed by chronoamperometry at a pair electrode. It behaves as if it were due to a slow electron transfer reaction. A diffusion model was composed of two cubic cells with different volumes in contact with each other by their faces, which worked as the boundary for the flux. Each cell contained one diffusing particle and solvent molecules for a given concentration. The particle moved randomly in the 3D lattice until it traversed the boundary. The number of the random steps before the traverse was equivalent to the relaxation time. It was proportional to ca 2/3 powers of the number of solvent molecules or was inversely proportional to 0.63 powers of the concentration. The relaxation time was roughly equivalent to the lapse of taking for the particle to visit every lattice site impartially.

  12. Microstructure, Compression Property and Shape Memory Effect of Equiatomic TaRu High Temperature Shape Memory Alloy

    Institute of Scientific and Technical Information of China (English)

    Xin GAO; Yufeng ZHENG; Wei CAI; Su ZHANG; Liancheng ZHAO

    2004-01-01

    The microstructure, phase transformation, compression property and strain recovery characteristics of equiatomic TaRu super high temperature shape memory alloy have been studied by optical microscope, XRD, DTA, compression tests and TEM observations. When cooling the alloy specimen from high temperature to the room temperature,β(parent phase)→β′(interphase) →β"(martensite) two-step phase transformations occur. The microstructure at room temperature show regularly arranged band morphology, with the monoclinic crystal structure. The twinning relationship between the martensite bands is determined to be (101) of Type I. Reorientation and coalescence of the martensite bands inside the variant happened during compression at room temperature. The β′→β reversible transformation contributes mainly the shape memory effect, with the maximum completely recovery strain of 2%.

  13. The Split Common Fixed Point Problem for a Family of Multivalued Quasinonexpansive Mappings and Totally Asymptotically Strictly Pseudocontractive Mappings in Banach Spaces

    Directory of Open Access Journals (Sweden)

    Ali Abkar

    2017-02-01

    Full Text Available In this paper, we introduce an iterative algorithm for solving the split common fixed point problem for a family of multi-valued quasinonexpansive mappings and totally asymptotically strictly pseudocontractive mappings, as well as for a family of totally quasi-ϕ-asymptotically nonexpansive mappings and k-quasi-strictly pseudocontractive mappings in the setting of Banach spaces. Our results improve and extend the results of Tang et al., Takahashi, Moudafi, Censor et al., and Byrne et al.

  14. Effects of task orientation on subsequent source memory as revealed by functional MRI*****

    Institute of Scientific and Technical Information of China (English)

    Xiuyan Guo; Lei Zhu; Li Zheng; Jianqi Li; Qianfeng Wang; Zhiliang Yang

    2013-01-01

    Episodic memories are composed of various interrelated elements, including those specific to items of central interest and those pertaining to related features, such as the color, shape, size, spatial location, temporal order, and media or modalities of presentation. Memory about a core item (such as a word, object, or picture) is cal ed item memory while memory about the context or related fea-tures of a core item is defined as source memory. What determines which sources within an episode are successful y remembered is of particular interest to researchers. Behavioral evidence suggests that the orientation of a memory task influences whether the related source of the item wil be re-membered later. This study explored changes in the hippocampus and prefrontal cortex while par-ticipants completed two tasks:an item-oriented task and a source-oriented task. We used functional MRI to investigate the neural mechanisms by which task orientation influences source encoding. We found that subsequent source memory effects in the right prefrontal cortex and hippocampus were modulated by task orientation, whereas task orientation modulated item memory effects in the prefrontal cortex. These findings highlight the possibility that the hippocampus contributes to the intentional encoding of item-source associations, whereas the prefrontal cortex is biased toward processing information to which attention is directed.

  15. Two-way Shape Memory Effect of NiTi under Compressive Loading Cycles

    Science.gov (United States)

    Yoo, Young Ik; Lee, Jung Ju

    In this study, the two-way shape memory effect (TWSME) of a Ni-54.5 at.% Ti alloy was investigated experimentally to develop a NiTi linear actuator. The two-way shape memory effect was induced through a compressive shape memory cycle composed of four steps: (1) loading to maximum deformation; (2) unloading; (3) heating; (4) and cooling. Six types of specimens (one solid cylindrical and five tubular) were used to obtain the twoway shape memory strain and two-way recovery stress and to evaluate the actuating capacity. The two-way actuating strain showed a convergent tendency after several training cycles for the same maximum deformation. A maximum value of the two-way strain was obtained for 7% of maximum deformation, independently of the geometry of the tubular specimens. The two-way strains obtained by the shape memory cycles and two-way recovery stress linearly increase as a function of the maximum deformation and the two-way strain, respectively, and the geometry of specimen affects the two-way recovery stress. Although the results show that sufficient recovery stress can be generated by either the two-way shape memory process or by the one-way shape memory process, the two-way shape memory process can be applied more conveniently to actuating applications.

  16. Combined effects of marijuana and nicotine on memory performance and hippocampal volume.

    Science.gov (United States)

    Filbey, Francesca M; McQueeny, Tim; Kadamangudi, Shrinath; Bice, Collette; Ketcherside, Ariel

    2015-10-15

    Combined use of marijuana (MJ) and tobacco is highly prevalent in today's population. Individual use of either substance is linked to structural brain changes and altered cognitive function, especially with consistent reports of hippocampal volume deficits and poorer memory performance. However, the combined effects of MJ and tobacco on hippocampal structure and on learning and memory processes remain unknown. In this study, we examined both the individual and combined effects of MJ and tobacco on hippocampal volumes and memory performance in four groups of adults taken from two larger studies: MJ-only users (n=36), nicotine-only (Nic-only, n=19), combined marijuana and nicotine users (MJ+Nic, n=19) and non-using healthy controls (n=16). Total bilateral hippocampal volumes and memory performance (WMS-III logical memory) were compared across groups controlling for total brain size and recent alcohol use. Results found MJ and MJ+Nic groups had smaller total hippocampal volumes compared to Nic-only and controls. No significant difference between groups was found between immediate and delayed story recall. However, the controls showed a trend for larger hippocampal volumes being associated with better memory scores, while MJ+Nic users showed a unique inversion, whereby smaller hippocampal volume was associated with better memory. Overall, results suggest abnormalities in the brain-behavior relationships underlying memory processes with combined use of marijuana and nicotine use. Further research will need to address these complex interactions between MJ and nicotine.

  17. Automatic and strategic effects in the guidance of attention by working memory representations.

    Science.gov (United States)

    Carlisle, Nancy B; Woodman, Geoffrey F

    2011-06-01

    Theories of visual attention suggest that working memory representations automatically guide attention toward memory-matching objects. Some empirical tests of this prediction have produced results consistent with working memory automatically guiding attention. However, others have shown that individuals can strategically control whether working memory representations guide visual attention. Previous studies have not independently measured automatic and strategic contributions to the interactions between working memory and attention. In this study, we used a classic manipulation of the probability of valid, neutral, and invalid cues to tease apart the nature of such interactions. This framework utilizes measures of reaction time (RT) to quantify the costs and benefits of attending to memory-matching items and infer the relative magnitudes of automatic and strategic effects. We found both costs and benefits even when the memory-matching item was no more likely to be the target than other items, indicating an automatic component of attentional guidance. However, the costs and benefits essentially doubled as the probability of a trial with a valid cue increased from 20% to 80%, demonstrating a potent strategic effect. We also show that the instructions given to participants led to a significant change in guidance distinct from the actual probability of events during the experiment. Together, these findings demonstrate that the influence of working memory representations on attention is driven by both automatic and strategic interactions. Copyright © 2010 Elsevier B.V. All rights reserved.

  18. Computerized working memory training has positive long-term effect in very low birthweight preschool children.

    Science.gov (United States)

    Grunewaldt, Kristine Hermansen; Skranes, Jon; Brubakk, Ann-Mari; Lähaugen, Gro C C

    2016-02-01

    Working memory deficits are frequently found in children born preterm and have been linked to learning disabilities, and cognitive and behavioural problems. Our aim was to evaluate if a computerized working memory training program has long-term positive effects on memory, learning, and behaviour in very-low-birthweight (VLBW) children at age 5 to 6 years. This prospective, intervention study included 20 VLBW preschool children in the intervention group and 17 age-matched, non-training VLBW children in the comparison group. The intervention group trained with the Cogmed JM working memory training program daily for 5 weeks (25 training sessions). Extensive neuropsychological assessment and parental questionnaires were performed 4 weeks after intervention and at follow-up 7 months later. For most of the statistical analyses, general linear models were applied. At follow-up, higher scores and increased or equal performance gain were found in the intervention group than the comparison group on memory for faces (p=0.012), narrative memory (p=0.002), and spatial span (p=0.003). No group differences in performance gain were found for attention and behaviour. Computerized working memory training seems to have positive and persisting effects on working memory, and visual and verbal learning, at 7-month follow-up in VLBW preschool children. We speculate that such training is beneficial by improving the ability to learn from the teaching at school and for further cognitive development. © 2015 Mac Keith Press.

  19. Effects of task orientation on subsequent source memory as revealed by functional MRI.

    Science.gov (United States)

    Guo, Xiuyan; Zhu, Lei; Zheng, Li; Li, Jianqi; Wang, Qianfeng; Yang, Zhiliang

    2013-09-15

    Episodic memories are composed of various interrelated elements, including those specific to items of central interest and those pertaining to related features, such as the color, shape, size, spatial location, temporal order, and media or modalities of presentation. Memory about a core item (such as a word, object, or picture) is called item memory while memory about the context or related fea-tures of a core item is defined as source memory. What determines which sources within an episode are successfully remembered is of particular interest to researchers. Behavioral evidence suggests that the orientation of a memory task influences whether the related source of the item will be re-membered later. This study explored changes in the hippocampus and prefrontal cortex while par-ticipants completed two tasks: an item-oriented task and a source-oriented task. We used functional MRI to investigate the neural mechanisms by which task orientation influences source encoding. We found that subsequent source memory effects in the right prefrontal cortex and hippocampus were modulated by task orientation, whereas task orientation modulated item memory effects in the prefrontal cortex. These findings highlight the possibility that the hippocampus contributes to the intentional encoding of item-source associations, whereas the prefrontal cortex is biased toward processing information to which attention is directed.

  20. Incorporation of memory effects in coarse-grained modeling via the Mori-Zwanzig formalism

    Science.gov (United States)

    Li, Zhen; Bian, Xin; Li, Xiantao; Karniadakis, George Em

    2015-12-01

    The Mori-Zwanzig formalism for coarse-graining a complex dynamical system typically introduces memory effects. The Markovian assumption of delta-correlated fluctuating forces is often employed to simplify the formulation of coarse-grained (CG) models and numerical implementations. However, when the time scales of a system are not clearly separated, the memory effects become strong and the Markovian assumption becomes inaccurate. To this end, we incorporate memory effects into CG modeling by preserving non-Markovian interactions between CG variables, and the memory kernel is evaluated directly from microscopic dynamics. For a specific example, molecular dynamics (MD) simulations of star polymer melts are performed while the corresponding CG system is defined by grouping many bonded atoms into single clusters. Then, the effective interactions between CG clusters as well as the memory kernel are obtained from the MD simulations. The constructed CG force field with a memory kernel leads to a non-Markovian dissipative particle dynamics (NM-DPD). Quantitative comparisons between the CG models with Markovian and non-Markovian approximations indicate that including the memory effects using NM-DPD yields similar results as the Markovian-based DPD if the system has clear time scale separation. However, for systems with small separation of time scales, NM-DPD can reproduce correct short-time properties that are related to how the system responds to high-frequency disturbances, which cannot be captured by the Markovian-based DPD model.