Phase Space Tweezers for Tailoring Cavity Fields by Quantum Zeno Dynamics

NASA Astrophysics Data System (ADS)

Raimond, J. M.; Sayrin, C.; Gleyzes, S.; Dotsenko, I.; Brune, M.; Haroche, S.; Facchi, P.; Pascazio, S.

2010-11-01

We discuss an implementation of quantum Zeno dynamics in a cavity quantum electrodynamics experiment. By performing repeated unitary operations on atoms coupled to the field, we restrict the field evolution in chosen subspaces of the total Hilbert space. This procedure leads to promising methods for tailoring nonclassical states. We propose to realize “tweezers” picking a coherent field at a point in phase space and moving it towards an arbitrary final position without affecting other nonoverlapping coherent components. These effects could be observed with a state-of-the-art apparatus.

Dissipation Assisted Quantum Memory with Coupled Spin Systems

NASA Astrophysics Data System (ADS)

Jiang, Liang; Verstraete, Frank; Cirac, Ignacio; Lukin, Mikhail

2009-05-01

Dissipative dynamics often destroys quantum coherences. However, one can use dissipation to suppress decoherence. A well-known example is the so-called quantum Zeno effect, in which one can freeze the evolution using dissipative processes (e.g., frequently projecting the system to its initial state). Similarly, the undesired decoherence of quantum bits can also be suppressed using controlled dissipation. We propose and analyze the use of this generalization of quantum Zeno effect for protecting the quantum information encoded in the coupled spin systems. This new approach may potentially enhance the performance of quantum memories, in systems such as nitrogen-vacancy color-centers in diamond.

Hand-Held Instrument Fights Acne, Tops Over-the-Counter Market

NASA Technical Reports Server (NTRS)

2007-01-01

Tyrell Inc., a Houston-based medical technologies company, was able to access engineering support in redesigning a heating element for a hand-held acne-fighting device through SATOP, NASA's Space Alliance Technology Outreach Program. SATOP put Tyrell in contact with The Boeing Company, which assessed the design and made several major contributions. The product, named Zeno, is now the highest selling over-the-counter medical device for the treatment of acne, and in 2006, Zeno was named the "SATOP Texas, Success Story of the Year." Zeno employs proprietary ClearPoint technology to provide relief of mild to moderate inflammatory acne by delivering a precisely controlled low-level dosage of heat to the blemish, causing the bacteria at the root of more than 90 percent of acne to self-destruct. Within its first year on the market, Zeno was cited by various publications for several awards, including Allure's 2005 "Best of Beauty," Marie Claire's "10 Best Gadgets for Girls," and Popular Science's 2005 "Best of What's New." A variation of the Zeno for use in treating herpetic lesions such as cold sores, by killing the virus that causes them, is currently undergoing FDA trials.

All-Optical Control of Linear and Nonlinear Energy Transfer via the Zeno Effect

NASA Astrophysics Data System (ADS)

Guo, Xiang; Zou, Chang-Ling; Jiang, Liang; Tang, Hong X.

2018-05-01

Microresonator-based nonlinear processes are fundamental to applications including microcomb generation, parametric frequency conversion, and harmonics generation. While nonlinear processes involving either second- (χ(2 )) or third- (χ(3 )) order nonlinearity have been extensively studied, the interaction between these two basic nonlinear processes has seldom been reported. In this paper we demonstrate a coherent interplay between second- and third- order nonlinear processes. The parametric (χ(2 ) ) coupling to a lossy ancillary mode shortens the lifetime of the target photonic mode and suppresses its density of states, preventing the photon emissions into the target photonic mode via the Zeno effect. Such an effect is then used to control the stimulated four-wave mixing process and realize a suppression ratio of 34.5.

Freezing Coherent Field Growth in a Cavity by the Quantum Zeno Effect

NASA Astrophysics Data System (ADS)

Bernu, J.; Deléglise, S.; Sayrin, C.; Kuhr, S.; Dotsenko, I.; Brune, M.; Raimond, J. M.; Haroche, S.

2008-10-01

We have frozen the coherent evolution of a field in a cavity by repeated measurements of its photon number. We use circular Rydberg atoms dispersively coupled to the cavity mode for an absorption-free photon counting. These measurements inhibit the growth of a field injected in the cavity by a classical source. This manifestation of the quantum Zeno effect illustrates the backaction of the photon number determination onto the field phase. The residual growth of the field can be seen as a random walk of its amplitude in the two-dimensional phase space. This experiment sheds light onto the measurement process and opens perspectives for active quantum feedback.

State dragging using the quantum Zeno effect

NASA Astrophysics Data System (ADS)

Hacohen-Gourgy, Shay; Martin, Leigh; GarcíA-Pintos, Luis Pedro; Dressel, Justin; Siddiqi, Irfan

The quantum Zeno effect is the suppression of Hamiltonian evolution by continuous measurement. It arises as a consequence of the quantum back-action pushing the state towards an eigenstate of the measurement operator. Rotating the operator at a rate much slower than the measurement rate will effectively drag the state with it. We use our recently developed scheme, which enables dynamic control of the measurement operator, to demonstrate this dragging effect on a superconducting transmon qubit. Since the system is continuously measured, the deterministic trajectory can be monitored, and quantum jumps can be detected in real-time. Furthermore, we perform this with two observables that are set to be either commuting or non-commuting, demonstrating new quantum dynamics. This work was supported by the Army Research Office and the Air Force Research Laboratory.

Quantum communication complexity using the quantum Zeno effect

NASA Astrophysics Data System (ADS)

Tavakoli, Armin; Anwer, Hammad; Hameedi, Alley; Bourennane, Mohamed

2015-07-01

The quantum Zeno effect (QZE) is the phenomenon in which the unitary evolution of a quantum state is suppressed, e.g., due to frequent measurements. Here, we investigate the use of the QZE in a class of communication complexity problems (CCPs). Quantum entanglement is known to solve certain CCPs beyond classical constraints. However, recent developments have yielded CCPs for which superclassical results can be obtained using only communication of a single d -level quantum state (qudit) as a resource. In the class of CCPs considered here, we show quantum reduction of complexity in three ways: using (i) entanglement and the QZE, (ii) a single qudit and the QZE, and (iii) a single qudit. We have performed a proof of concept experimental demonstrations of three party CCP protocol based on single-qubit communication with and without QZE.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shao Xiaoqiang; Wang Hongfu; Zhang Shou

We present an approach for implementation of a 1->3 orbital state quantum cloning machine based on the quantum Zeno dynamics via manipulating three rf superconducting quantum interference device (SQUID) qubits to resonantly interact with a superconducting cavity assisted by classical fields. Through appropriate modulation of the coupling constants between rf SQUIDs and classical fields, the quantum cloning machine can be realized within one step. We also discuss the effects of decoherence such as spontaneous emission and the loss of cavity in virtue of master equation. The numerical simulation result reveals that the quantum cloning machine is especially robust against themore » cavity decay, since all qubits evolve in the decoherence-free subspace with respect to cavity decay due to the quantum Zeno dynamics.« less

Contemporary Criticism and the Return of Zeno.

ERIC Educational Resources Information Center

Harris, Wendell V.

1983-01-01

Suggests that contemporary critical literary theories such as hermaneutics, reader-response, speech-act, structuralism, and deconstructionism share with pre-Platonic Eleatic thought a distrust of cause-and-effect reasoning and an emphasis on paradox. (MM)

The quantum Zeno effect in double well tunnelling

NASA Astrophysics Data System (ADS)

Lerner, L.

2018-05-01

Measurement lies at the heart of quantum theory, and introductory textbooks in quantum mechanics cover the measurement problem in topics such as the Schrödinger’s cat thought experiment, the EPR problem, and the quantum Zeno effect (QZE). In this article we present a new treatment of the QZE suitable for undergraduate students, for the case of a particle tunnelling between two wells while being observed in one of the wells. The analysis shows that as the observation rate increases, the tunnelling rate tends towards zero, in accordance with Zeno’s maxim ‘a watched pot never boils’. The method relies on decoherence theory, which replaces aspects of quantum collapse by the Schrödinger evolution of an open system, and its recently simplified treatment for undergraduates. Our presentation uses concepts familiar to undergraduate students, so that calculations involving many-body theory and the formal properties of the density matrix are avoided.

Direct counterfactual communication via quantum Zeno effect

NASA Astrophysics Data System (ADS)

Cao, Yuan; Li, Yu-Huai; Cao, Zhu; Yin, Juan; Chen, Yu-Ao; Yin, Hua-Lei; Chen, Teng-Yun; Ma, Xiongfeng; Peng, Cheng-Zhi; Pan, Jian-Wei

2017-05-01

Intuition from our everyday lives gives rise to the belief that information exchanged between remote parties is carried by physical particles. Surprisingly, in a recent theoretical study [Salih H, Li ZH, Al-Amri M, Zubairy MS (2013) Phys Rev Lett 110:170502], quantum mechanics was found to allow for communication, even without the actual transmission of physical particles. From the viewpoint of communication, this mystery stems from a (nonintuitive) fundamental concept in quantum mechanics—wave-particle duality. All particles can be described fully by wave functions. To determine whether light appears in a channel, one refers to the amplitude of its wave function. However, in counterfactual communication, information is carried by the phase part of the wave function. Using a single-photon source, we experimentally demonstrate the counterfactual communication and successfully transfer a monochrome bitmap from one location to another by using a nested version of the quantum Zeno effect.

Direct counterfactual communication via quantum Zeno effect.

PubMed

Cao, Yuan; Li, Yu-Huai; Cao, Zhu; Yin, Juan; Chen, Yu-Ao; Yin, Hua-Lei; Chen, Teng-Yun; Ma, Xiongfeng; Peng, Cheng-Zhi; Pan, Jian-Wei

2017-05-09

Intuition from our everyday lives gives rise to the belief that information exchanged between remote parties is carried by physical particles. Surprisingly, in a recent theoretical study [Salih H, Li ZH, Al-Amri M, Zubairy MS (2013) Phys Rev Lett 110:170502], quantum mechanics was found to allow for communication, even without the actual transmission of physical particles. From the viewpoint of communication, this mystery stems from a (nonintuitive) fundamental concept in quantum mechanics-wave-particle duality. All particles can be described fully by wave functions. To determine whether light appears in a channel, one refers to the amplitude of its wave function. However, in counterfactual communication, information is carried by the phase part of the wave function. Using a single-photon source, we experimentally demonstrate the counterfactual communication and successfully transfer a monochrome bitmap from one location to another by using a nested version of the quantum Zeno effect.

Direct counterfactual communication via quantum Zeno effect

PubMed Central

Cao, Yuan; Li, Yu-Huai; Cao, Zhu; Yin, Juan; Chen, Yu-Ao; Yin, Hua-Lei; Chen, Teng-Yun; Ma, Xiongfeng; Peng, Cheng-Zhi; Pan, Jian-Wei

2017-01-01

Intuition from our everyday lives gives rise to the belief that information exchanged between remote parties is carried by physical particles. Surprisingly, in a recent theoretical study [Salih H, Li ZH, Al-Amri M, Zubairy MS (2013) Phys Rev Lett 110:170502], quantum mechanics was found to allow for communication, even without the actual transmission of physical particles. From the viewpoint of communication, this mystery stems from a (nonintuitive) fundamental concept in quantum mechanics—wave-particle duality. All particles can be described fully by wave functions. To determine whether light appears in a channel, one refers to the amplitude of its wave function. However, in counterfactual communication, information is carried by the phase part of the wave function. Using a single-photon source, we experimentally demonstrate the counterfactual communication and successfully transfer a monochrome bitmap from one location to another by using a nested version of the quantum Zeno effect. PMID:28442568

ZENO: N-body and SPH Simulation Codes

NASA Astrophysics Data System (ADS)

Barnes, Joshua E.

2011-02-01

The ZENO software package integrates N-body and SPH simulation codes with a large array of programs to generate initial conditions and analyze numerical simulations. Written in C, the ZENO system is portable between Mac, Linux, and Unix platforms. It is in active use at the Institute for Astronomy (IfA), at NRAO, and possibly elsewhere. Zeno programs can perform a wide range of simulation and analysis tasks. While many of these programs were first created for specific projects, they embody algorithms of general applicability and embrace a modular design strategy, so existing code is easily applied to new tasks. Major elements of the system include: Structured data file utilities facilitate basic operations on binary data, including import/export of ZENO data to other systems.Snapshot generation routines create particle distributions with various properties. Systems with user-specified density profiles can be realized in collisionless or gaseous form; multiple spherical and disk components may be set up in mutual equilibrium.Snapshot manipulation routines permit the user to sift, sort, and combine particle arrays, translate and rotate particle configurations, and assign new values to data fields associated with each particle.Simulation codes include both pure N-body and combined N-body/SPH programs: Pure N-body codes are available in both uniprocessor and parallel versions.SPH codes offer a wide range of options for gas physics, including isothermal, adiabatic, and radiating models. Snapshot analysis programs calculate temporal averages, evaluate particle statistics, measure shapes and density profiles, compute kinematic properties, and identify and track objects in particle distributions.Visualization programs generate interactive displays and produce still images and videos of particle distributions; the user may specify arbitrary color schemes and viewing transformations.

Engineering steady-state entanglement via dissipation and quantum Zeno dynamics in an optical cavity.

PubMed

Li, Dong-Xiao; Shao, Xiao-Qiang; Wu, Jin-Hui; Yi, X X

2017-10-01

A new mechanism is proposed for dissipatively preparing maximal Bell entangled state of two atoms in an optical cavity. This scheme integrates the spontaneous emission, the light shift of atoms in the presence of dispersive microwave field, and the quantum Zeno dynamics induced by continuous coupling, to obtain a unique steady state irrespective of initial state. Even for a large cavity decay, a high-fidelity entangled state is achievable at a short convergence time, since the occupation of the cavity mode is inhibited by the Zeno requirement. Therefore, a low single-atom cooperativity C=g 2 /(κγ) is good enough for realizing a high fidelity of entanglement in a wide range of decoherence parameters. As a straightforward extension, the feasibility for preparation of two-atom Knill-Laflamme-Milburn state with the same mechanism is also discussed.

Observing quantum trajectories: From Mott’s problem to quantum Zeno effect and back

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gosson, Maurice de, E-mail: maurice.de.gosson@univie.ac.at; Hiley, Basil; TPRU, Birkbeck, University of London, Malet Street, London WC1E 7HX

2016-11-15

The experimental results of Kocsis et al., Mahler et al. and the proposed experiments of Morley et al. show that it is possible to construct “trajectories” in interference regions in a two-slit interferometer. These results call for a theoretical re-appraisal of the notion of a “quantum trajectory” first introduced by Dirac and in the present paper we re-examine this notion from the Bohm perspective based on Hamiltonian flows. In particular, we examine the short-time propagator and the role that the quantum potential plays in determining the form of these trajectories. These trajectories differ from those produced in a typical particlemore » tracker and the key to this difference lies in the active suppression of the quantum potential necessary to produce Mott-type trajectories. We show, using a rigorous mathematical argument, how the active suppression of this potential arises. Finally we discuss in detail how this suppression also accounts for the quantum Zeno effect.« less

Rotations of a logical qubit using the quantum Zeno effect extended to a manifold

NASA Astrophysics Data System (ADS)

Touzard, S.; Grimm, A.; Leghtas, Z.; Mundhada, S. O.; Reinhold, P.; Heeres, R.; Axline, C.; Reagor, M.; Chou, K.; Blumoff, J.; Sliwa, K. M.; Shankar, S.; Frunzio, L.; Schoelkopf, R. J.; Mirrahimi, M.; Devoret, M. H.

Encoding Quantum Information in the large Hilbert space of a harmonic oscillator has proven to have advantages over encoding in a register of physical qubits, but has also provided new challenges. While recent experiments have demonstrated quantum error correction using such an encoding based on superpositions of coherent states, these codes are still susceptible to non-corrected errors and lack controllability: compared to physical qubits it is hard to make arbitrary states and to perform operations on them. Our approach is to engineer the dynamics and the dissipation of a microwave cavity to implement a continuous dissipative measurement yielding two degenerate outcomes. This extends the quantum Zeno effect to a manifold, which in our case is spanned by two coherent states of opposite phases. In this second talk we present the result and analysis of an experiment that performs rotations on a logical qubit encoded in this protected manifold. Work supported by: ARO, ONR, AFOSR and YINQE.

Rotations of a logical qubit using the quantum Zeno effect extended to a manifold - Part 1

NASA Astrophysics Data System (ADS)

Grimm, A.; Touzard, S.; Leghtas, Z.; Mundhada, S. O.; Reinhold, P.; Heeres, R.; Axline, C.; Reagor, M.; Chou, K.; Blumoff, J.; Sliwa, K. M.; Shankar, S.; Frunzio, L.; Schoelkopf, R. J.; Mirrahimi, M.; Devoret, M. H.

Encoding Quantum Information in the large Hilbert space of a harmonic oscillator has proven to have advantages over encoding in a register of physical qubits, but has also provided new challenges. While recent experiments have demonstrated quantum error correction using such an encoding based on superpositions of coherent states, these codes are still susceptible to non-corrected errors and lack controllability: compared to physical qubits it is hard to make arbitrary states and to perform operations on them. Our approach is to engineer the dynamics and the dissipation of a microwave cavity to implement a continuous dissipative measurement yielding two degenerate outcomes. This extends the quantum Zeno effect to a manifold, which in our case is spanned by two coherent states of opposite phases. In this first talk we present the concept and architecture of an experiment that performs rotations on a logical qubit encoded in this protected manifold. Work supported by: ARO, ONR, AFOSR and YINQE.

Preliminary flight results from the second U.S. Microgravity Payload (USMP-2)

NASA Technical Reports Server (NTRS)

Curreri, Peter; Reiss, Donald

1994-01-01

The second U.S. Microgravity Payload (USMP-2) was flown on the Space Shuttle in March 1994. It carried four major microgravity experiments plus a sophisticated accelerometer system to record the microgravity environment during USMP-2 operations. The USMP program is designed to accommodate experiments requiring extensive resources short of a full Spacelab mission, and the experiments are remotely operated and monitored. Results are reviewed from the four experiments: the Advanced Automated Directional Solidification Facility (AADSF), the Isothermal Dendrite Growth Experiment (IDGE), the Materiel por Etude des Phenomenes Interessant la Soldification sur Terre et en Orbite (MEPHISTO), and the Critical Fluid Light Scattering Experiment (Zeno). AASDF grew what is expected to be the largest steady-state sample ever of HgCdTe during 240 hours of operation. IDGE provided 60 growth cycles over a wide range of supercooling conditions studying the dendritic solidification of succinonitrile. MEPHISTO achieved 55 melt-solidify cycles and grew over 1 m of Bi/Sn alloy. Zeno located the critical point temperature for liquid Xe to 0.00001 K. IDGE and Zeno also provided the most extensive demonstrations to date of telescience.

Flexible and experimentally feasible shortcut to quantum Zeno dynamic passage

NASA Astrophysics Data System (ADS)

Li, Wenlin; Zhang, Fengyang; Jiang, Yunfeng; Li, Chong; Song, Heshan

2016-10-01

We propose and discuss a theoretical scheme to speed up Zeno dynamic passage by an external acceleration Hamiltonian. This scheme is a flexible and experimentally feasible acceleration because the acceleration Hamiltonian does not adhere rigidly to an invariant relationship, whereas it can be a more general form ∑uj (t)Hcj. Here Hcj can be arbitrarily selected without any limitation, and therefore one can always construct an acceleration Hamiltonian by only using realizable Hcj. Applying our scheme, we finally design an experimentally feasible Hamiltonian as an example to speed up an entanglement preparation passage.

Protocol for Direct Counterfactual Quantum Communication

NASA Astrophysics Data System (ADS)

Salih, Hatim; Li, Zheng-Hong; Al-Amri, M.; Zubairy, M. Suhail

2013-04-01

It has long been assumed in physics that for information to travel between two parties in empty space, “Alice” and “Bob,” physical particles have to travel between them. Here, using the “chained” quantum Zeno effect, we show how, in the ideal asymptotic limit, information can be transferred between Alice and Bob without any physical particles traveling between them.

Antibunched emission of photon pairs via quantum Zeno blockade.

PubMed

Huang, Yu-Ping; Kumar, Prem

2012-01-20

We propose a new methodology, namely, the "quantum Zeno blockade," for managing light scattering at a few-photon level in general nonlinear-optical media, such as crystals, fibers, silicon microrings, and atomic vapors. Using this tool, antibunched emission of photon pairs can be achieved, leading to potent quantum-optics applications such as deterministic entanglement generation without the need for heralding. In a practical implementation using an on-chip toroidal microcavity immersed in rubidium vapor, we estimate that high-fidelity entangled photons can be produced on-demand at MHz rates or higher, corresponding to an improvement of ≳10(7) times from the state-of-the-art. © 2012 American Physical Society

Aristotle Meets Zeno: Psychophysiological Evidence

PubMed Central

Papageorgiou, Charalabos; Stachtea, Xanthi; Papageorgiou, Panos; Alexandridis, Antonio T.

2016-01-01

This study, a tribute to Aristotle's 2400 years, used a juxtaposition of valid Aristotelian arguments to the paradoxes formulated by Zeno the Eleatic, in order to investigate the electrophysiological correlates of attentional and /or memory processing effects in the course of deductive reasoning. Participants undertook reasoning tasks based on visually presented arguments which were either (a) valid (Aristotelian) statements or (b) paradoxes. We compared brain activation patterns while participants maintained the premises / conclusions of either the valid statements or the paradoxes in working memory (WM). Event-related brain potentials (ERPs), specifically the P300 component of ERPs, were recorded during the WM phase, during which participants were required to draw a logical conclusion regarding the correctness of the valid syllogisms or the paradoxes. During the processing of paradoxes, results demonstrated a more positive event-related potential deflection (P300) across frontal regions, whereas processing of valid statements was associated with noticeable P300 amplitudes across parieto-occipital regions. These findings suggest that paradoxes mobilize frontal attention mechanisms, while valid deduction promotes parieto-occipital activity associated with attention and/or subsequent memory processing. PMID:28033333

Aristotle Meets Zeno: Psychophysiological Evidence.

PubMed

Papageorgiou, Charalabos; Stachtea, Xanthi; Papageorgiou, Panos; Alexandridis, Antonio T; Tsaltas, Eleftheria; Angelopoulos, Elias

2016-01-01

This study, a tribute to Aristotle's 2400 years, used a juxtaposition of valid Aristotelian arguments to the paradoxes formulated by Zeno the Eleatic, in order to investigate the electrophysiological correlates of attentional and /or memory processing effects in the course of deductive reasoning. Participants undertook reasoning tasks based on visually presented arguments which were either (a) valid (Aristotelian) statements or (b) paradoxes. We compared brain activation patterns while participants maintained the premises / conclusions of either the valid statements or the paradoxes in working memory (WM). Event-related brain potentials (ERPs), specifically the P300 component of ERPs, were recorded during the WM phase, during which participants were required to draw a logical conclusion regarding the correctness of the valid syllogisms or the paradoxes. During the processing of paradoxes, results demonstrated a more positive event-related potential deflection (P300) across frontal regions, whereas processing of valid statements was associated with noticeable P300 amplitudes across parieto-occipital regions. These findings suggest that paradoxes mobilize frontal attention mechanisms, while valid deduction promotes parieto-occipital activity associated with attention and/or subsequent memory processing.

Fast implementation of the 1\\rightarrow3 orbital state quantum cloning machine

NASA Astrophysics Data System (ADS)

Lin, Jin-Zhong

2018-05-01

We present a scheme to implement a 1→3 orbital state quantum cloning machine assisted by quantum Zeno dynamics. By constructing shortcuts to adiabatic passage with transitionless quantum driving, we can complete this scheme effectively and quickly in one step. The effects of decoherence, including spontaneous emission and the decay of the cavity, are also discussed. The numerical simulation results show that high fidelity can be obtained and the feasibility analysis indicates that this can also be realized in experiments.

Quantum computation with trapped ions in an optical cavity.

PubMed

Pachos, Jiannis; Walther, Herbert

2002-10-28

Two-qubit logical gates are proposed on the basis of two atoms trapped in a cavity setup and commonly addressed by laser fields. Losses in the interaction by spontaneous transitions are efficiently suppressed by employing adiabatic transitions and the quantum Zeno effect. Dynamical and geometrical conditional phase gates are suggested. This method provides fidelity and a success rate of its gates very close to unity. Hence, it is suitable for performing quantum computation.

Counterfactual Assessment of Decoherence in Quantum Systems

NASA Astrophysics Data System (ADS)

Russo, Onofrio; Jiang, Liang

2013-03-01

Quantum Zeno effect occurs when the system is observed for unusually short observation times, t, where the probability of the transition between different quantum states is known to be proportional to t2. This results in a decrease in the probability of transitions between states and the consequent decrease in decoherence. We consider the conditions in which these observations are made counterfactual to assess whether this results in a significant change in decoherence.

Quantum Zeno Effect in the Strong Measurement Regime of Circuit Quantum Electrodynamics

DTIC Science & Technology

2016-05-17

andNV centers [16]. In driven superconducting qubits, the QZEhas been indirectly inferred from the transition between coherent Rabi oscillations and...qubit will undergo sinusoidal Rabi oscillations between states at frequency pW 2 , whereΩ depends on the strength of the resonant drive. Repeated...where the qubit dynamics dependmainly on qubit drive andmeasurement strength. Because of the presence of the Rabi drive, this treatment is only valid

Sensitivity of measurement-based purification processes to inner interactions

NASA Astrophysics Data System (ADS)

Militello, Benedetto; Napoli, Anna

2018-02-01

The sensitivity of a repeated measurement-based purification scheme to additional undesired couplings is analyzed, focusing on the very simple and archetypical system consisting of two two-level systems interacting with a repeatedly measured one. Several regimes are considered and in the strong coupling limit (i.e., when the coupling constant of the undesired interaction is very large) the occurrence of a quantum Zeno effect is proven to dramatically jeopardize the efficiency of the purification process.

SITE TECHNOLOGY CAPSULE: ZENOGEM™ WASTEWATER TREATMENT PROCESS

EPA Science Inventory

Zenon Environmental System's ZenoGem™ Wastewater Treatment Process treats aqueous media contaminated with volatile/semi-volatile organic compounds. This technology combines aerobic biological treatment to remove biodegradable organic compounds with ultrafiltration to separate res...

Deterministic generation of multiparticle entanglement by quantum Zeno dynamics.

PubMed

Barontini, Giovanni; Hohmann, Leander; Haas, Florian; Estève, Jérôme; Reichel, Jakob

2015-09-18

Multiparticle entangled quantum states, a key resource in quantum-enhanced metrology and computing, are usually generated by coherent operations exclusively. However, unusual forms of quantum dynamics can be obtained when environment coupling is used as part of the state generation. In this work, we used quantum Zeno dynamics (QZD), based on nondestructive measurement with an optical microcavity, to deterministically generate different multiparticle entangled states in an ensemble of 36 qubit atoms in less than 5 microseconds. We characterized the resulting states by performing quantum tomography, yielding a time-resolved account of the entanglement generation. In addition, we studied the dependence of quantum states on measurement strength and quantified the depth of entanglement. Our results show that QZD is a versatile tool for fast and deterministic entanglement generation in quantum engineering applications. Copyright © 2015, American Association for the Advancement of Science.

A quantum probability perspective on borderline vagueness.

PubMed

Blutner, Reinhard; Pothos, Emmanuel M; Bruza, Peter

2013-10-01

The term "vagueness" describes a property of natural concepts, which normally have fuzzy boundaries, admit borderline cases, and are susceptible to Zeno's sorites paradox. We will discuss the psychology of vagueness, especially experiments investigating the judgment of borderline cases and contradictions. In the theoretical part, we will propose a probabilistic model that describes the quantitative characteristics of the experimental finding and extends Alxatib's and Pelletier's () theoretical analysis. The model is based on a Hopfield network for predicting truth values. Powerful as this classical perspective is, we show that it falls short of providing an adequate coverage of the relevant empirical results. In the final part, we will argue that a substantial modification of the analysis put forward by Alxatib and Pelletier and its probabilistic pendant is needed. The proposed modification replaces the standard notion of probabilities by quantum probabilities. The crucial phenomenon of borderline contradictions can be explained then as a quantum interference phenomenon. © 2013 Cognitive Science Society, Inc.

Direct counterfactual transmission of a quantum state

NASA Astrophysics Data System (ADS)

Li, Zheng-Hong; Al-Amri, M.; Zubairy, M. Suhail

2015-11-01

We show that an unknown quantum state can be transferred with neither quantum nor classical particle traveling in the transmission channel. Our protocol does not require prearranged entangled photon pairs and Bell measurements. By utilizing quantum Zeno effect and counterfactuality, we can entangle and disentangle a photon and an atom by nonlocal interaction. It is shown that quantum information is completely transferred from an atom to photon due to controllable disentanglement processes. There is no need to cross-check the result via classical channels.

Strong Photoassociation in Ultracold Fermions

NASA Astrophysics Data System (ADS)

Jing, Li; Jamison, Alan; Rvachov, Timur; Ebadi, Sepher; Son, Hyungmok; Jiang, Yijun; Zwierlein, Martin; Ketterle, Wolfgang

2016-05-01

Despite many studies there are still open questions about strong photoassociation in ultracold gases. Photoassociation occurs only at short range and thus can be used as a tool to probe and control the two-body correlation function in an interacting many-body system and to engineer Hamiltonians using dissipation. We propose the possibility to slow down decoherence by photoassociation through the quantum Zeno effect. This can realized by shining strong photoassociation light on the superposition of the lowest two hyperfine states of Lithium 6. NSF, ARO-MURI, Samsung, NSERC.

Maxwell’s demon in the quantum-Zeno regime and beyond

NASA Astrophysics Data System (ADS)

Engelhardt, G.; Schaller, G.

2018-02-01

The long-standing paradigm of Maxwell’s demon is till nowadays a frequently investigated issue, which still provides interesting insights into basic physical questions. Considering a single-electron transistor, where we implement a Maxwell demon by a piecewise-constant feedback protocol, we investigate quantum implications of the Maxwell demon. To this end, we harness a dynamical coarse-graining method, which provides a convenient and accurate description of the system dynamics even for high measurement rates. In doing so, we are able to investigate the Maxwell demon in a quantum-Zeno regime leading to transport blockade. We argue that there is a measurement rate providing an optimal performance. Moreover, we find that besides building up a chemical gradient, there can be also a regime where the feedback loop additionally extracts energy, which results from the energy non-conserving character of the projective measurement.

Coherent triplet excitation suppresses the heading error of the avian compass

NASA Astrophysics Data System (ADS)

Katsoprinakis, G. E.; Dellis, A. T.; Kominis, I. K.

2010-08-01

Radical-ion pair reactions are currently understood to underlie the biochemical magnetic compass of migratory birds. It was recently shown that radical-ion pair reactions form a rich playground for the application of quantum-information-science concepts and effects. We will show here that the intricate interplay between the quantum Zeno effect and the coherent excitation of radical-ion pairs leads to an exquisite angular sensitivity of the reaction yields. This results in a significant and previously unanticipated suppression of the avian compass heading error, opening the way to quantum engineering precision biological sensors.

ZENON ENVIRONMENTAL INC., ZENOGEM™ BIOLOGICAL AND ULTRAFILTRATION TECHNOLOGY; INNOVATIVE TECHNOLOGY EVALUATION REPORT

EPA Science Inventory

This report summarizes the results of a field demonstration conducted under the SITE Program. The technology which was demonstrated was a wastewater treatment technology developed by Zenon Environmental Inc. The process, named ZenoGem™, integrates biological treatment with memb...

Preparing Schrodinger cat states by parametric pumping

NASA Astrophysics Data System (ADS)

Leghtas, Zaki; Touzard, Steven; Pop, Ioan; Vlastakis, Brian; Zalys-Geller, Evan; Albert, Victor V.; Jiang, Liang; Frunzio, Luigi; Schoelkopf, Robert J.; Mirrahimi, Mazyar; Devoret, Michel H.

2014-03-01

Maintaining a quantum superposition state of light in a cavity has important applications for quantum error correction. We present an experimental protocol based on parametric pumping and Josephson circuits, which could prepare a Schrodinger cat state in a cavity. This is achieved by engineering a dissipative environment, which exchanges only pairs or quadruples of photons with our cavity mode. The dissipative nature of this preparation would lead to the observation of a dynamical Zeno effect, where the competition between a coherent drive and the dissipation reveals non trivial dynamics. Work supported by: IARPA, ARO, and NSF.

Dissipative preparation of steady Greenberger-Horne-Zeilinger states for Rydberg atoms with quantum Zeno dynamics

NASA Astrophysics Data System (ADS)

Shao, X. Q.; Wu, J. H.; Yi, X. X.; Long, Gui-Lu

2017-12-01

Inspired by a recent work [F. Reiter, D. Reeb, and A. S. Sørensen, Phys. Rev. Lett. 117, 040501 (2016), 10.1103/PhysRevLett.117.040501], we present a simplified proposal for dissipatively preparing a Greenberger-Horne-Zeilinger (GHZ) state of three Rydberg atoms in a cavity. The Z pumping is implemented under the action of the spontaneous emission of Λ -type atoms and the quantum Zeno dynamics induced by strong continuous coupling. In the meantime, a dissipative Rydberg pumping breaks up the stability of the state | GHZ+〉 in the process of Z pumping, making | GHZ-〉 the unique steady state of the system. Compared with the former scheme, the number of driving fields acting on atoms is greatly reduced and only a single-mode cavity is required. The numerical simulation of the full master equation reveals that a high fidelity ˜98 % can be obtained with the currently achievable parameters in the Rydberg-atom-cavity system.

Hazardous Waste Cleanup: Thermo King de Puerto Rico Incorporated in Arecibo, Puerto Rico

EPA Pesticide Factsheets

Thermo King de Puerto Rico, Inc. facility is located in the Zeno Gandia Industrial Area in Arecibo, Puerto Rico. Major features of the facility include six buildings used for manufacturing and storage, a wastewater treatment plant, a hazardous waste and no

Good Phonic Generalizations for Decoding

ERIC Educational Resources Information Center

Gates, Louis

2007-01-01

An exhaustive analysis of 88,641 individual letters and letter combinations within 16,928 words drawn from the Zeno, et al. word list unveiled remarkable phonic transparency. The individual letter and letter combinations sorted into just six general categories: three basic categories of vowels (single vowels, vowel digraphs, and final…

Thermal baths as quantum resources: more friends than foes?

NASA Astrophysics Data System (ADS)

Kurizki, Gershon; Shahmoon, Ephraim; Zwick, Analia

2015-12-01

In this article we argue that thermal reservoirs (baths) are potentially useful resources in processes involving atoms interacting with quantized electromagnetic fields and their applications to quantum technologies. One may try to suppress the bath effects by means of dynamical control, but such control does not always yield the desired results. We wish instead to take advantage of bath effects, that do not obliterate ‘quantumness’ in the system-bath compound. To this end, three possible approaches have been pursued by us. (i) Control of a quantum system faster than the correlation time of the bath to which it couples: such control allows us to reveal quasi-reversible/coherent dynamical phenomena of quantum open systems, manifest by the quantum Zeno or anti-Zeno effects (QZE or AZE, respectively). Dynamical control methods based on the QZE are aimed not only at protecting the quantumness of the system, but also diagnosing the bath spectra or transferring quantum information via noisy media. By contrast, AZE-based control is useful for fast cooling of thermalized quantum systems. (ii) Engineering the coupling of quantum systems to selected bath modes: this approach, based on field-atom coupling control in cavities, waveguides and photonic band structures, allows one to drastically enhance the strength and range of atom-atom coupling through the mediation of the selected bath modes. More dramatically, it allows us to achieve bath-induced entanglement that may appear paradoxical if one takes the conventional view that coupling to baths destroys quantumness. (iii) Engineering baths with appropriate non-flat spectra: this approach is a prerequisite for the construction of the simplest and most efficient quantum heat machines (engines and refrigerators). We may thus conclude that often thermal baths are ‘more friends than foes’ in quantum technologies.

Many-Body Physics in Long-Range Interacting Quantum Systems

NASA Astrophysics Data System (ADS)

Zhu, Bihui

Ultracold atomic and molecular systems provide a useful platform for understanding quantum many-body physics. Recent progresses in AMO experiments enable access to systems exhibiting long-range interactions, opening a window for exploring the interplay between long-range interactions and dissipation. In this thesis, I develop theoretical approaches to study non-equilibrium dynamics in systems where such interplay is crucial. I first focus on a system of KRb molecules, where dipolar interactions and fast chemical reactions coexist. Using a classical kinetic theory and Monte Carlo methods, I study the evaporative cooling in a quasi-two-dimensional trap, and develop a protocol to reach quantum degeneracy. I also study the case where molecules are loaded into an optical lattice, and show that the strong dissipation induces a quantum Zeno effect, which suppresses the molecule loss. The analysis requires including multiple bands to explain recent experimental measurements, and can be used to determine the molecular filling fraction. I also investigate a system of radiating atoms, which experience long-range elastic and dissipative interactions. I explore the collective behavior of atoms and the role of atomic motion. The model is validated by comparison with a recent light scattering experiment using Sr atoms. I also show that incoherently pumped dipoles can undergo a dynamical phase transition to synchronization, and study its signature in the quantum regime.

Tripartite counterfactual entanglement distribution.

PubMed

Chen, Yuanyuan; Gu, Xuemei; Jiang, Dong; Xie, Ling; Chen, Lijun

2015-08-10

We propose two counterfactual schemes for tripartite entanglement distribution without any physical particles travelling through the quantum channel. One scheme arranges three participators to connect with the absorption object by using switch. Using the "chained" quantum Zeno effect, three participators can accomplish the task of entanglement distribution with unique counterfactual interference probability. Another scheme uses Michelson-type interferometer to swap two entanglement pairs such that the photons of three participators are entangled. Moreover, the distance of entanglement distribution is doubled as two distant absorption objects are used. We also discuss the implementation issues to show that the proposed schemes can be realized with current technology.

Highlights of the Zeno Results from the USMP-2 Mission

NASA Technical Reports Server (NTRS)

Gammon, Robert W.; Shaumeyer, J. N.; Briggs, Matthew E.; Boukari, Hacene; Gent, David A.; Wilkinson, R. Allen

1995-01-01

The Zeno instrument, a High-precision, light-scattering spectrometer, was built to measure the decay rates of density fluctuations in xenon near its liquid-vapor critical point in the low-gravity environment of the U.S. Space Shuttle. Eliminating the severe density gradients created in a critical fluid by Earth's gravity, we were able to make measurements to within 100 microKelvin of the critical point. The instrument flew for fourteen days in March, 1994 on the Space Shuttle Columbia, STS-62 flight, as part of the very successful USMP-2 payload. We describe the instrument and document its performance on orbit, showing that it comfortably reached the desired 3 microKelvin temperature control of the sample. Locating the critical temperature of the sample on orbit was a scientific challenge; we discuss the advantages and short-comings of the two techniques we used. Finally we discuss problems encountered with making measurements of the turbidity of the sample, and close with the results of the measurement of the decay rates of the critical-point fluctuations.

Quantum walks: The first detected passage time problem

NASA Astrophysics Data System (ADS)

Friedman, H.; Kessler, D. A.; Barkai, E.

2017-03-01

Even after decades of research, the problem of first passage time statistics for quantum dynamics remains a challenging topic of fundamental and practical importance. Using a projective measurement approach, with a sampling time τ , we obtain the statistics of first detection events for quantum dynamics on a lattice, with the detector located at the origin. A quantum renewal equation for a first detection wave function, in terms of which the first detection probability can be calculated, is derived. This formula gives the relation between first detection statistics and the solution of the corresponding Schrödinger equation in the absence of measurement. We illustrate our results with tight-binding quantum walk models. We examine a closed system, i.e., a ring, and reveal the intricate influence of the sampling time τ on the statistics of detection, discussing the quantum Zeno effect, half dark states, revivals, and optimal detection. The initial condition modifies the statistics of a quantum walk on a finite ring in surprising ways. In some cases, the average detection time is independent of the sampling time while in others the average exhibits multiple divergences as the sampling time is modified. For an unbounded one-dimensional quantum walk, the probability of first detection decays like (time)(-3 ) with superimposed oscillations, with exceptional behavior when the sampling period τ times the tunneling rate γ is a multiple of π /2 . The amplitude of the power-law decay is suppressed as τ →0 due to the Zeno effect. Our work, an extended version of our previously published paper, predicts rich physical behaviors compared with classical Brownian motion, for which the first passage probability density decays monotonically like (time)-3 /2, as elucidated by Schrödinger in 1915.

Time evolution, Lamb shift, and emission spectra of spontaneous emission of two identical atoms

NASA Astrophysics Data System (ADS)

Wang, Da-Wei; Li, Zheng-Hong; Zheng, Hang; Zhu, Shi-Yao

2010-04-01

A unitary transformation method is used to investigate the dynamic evolution of two multilevel atoms, in the basis of symmetric and antisymmetric states, with one atom being initially prepared in the first excited state and the other in the ground state. The unitary transformation guarantees that our calculations are based on the ground state of the atom-field system and the self-energy is subtracted at the beginning. The total Lamb shifts of the symmetric and antisymmetric states are divided into transformed shift and dynamic shift. The transformed shift is due to emitting and reabsorbing of virtual photons, by a single atom (nondynamic single atomic shift) and between the two atoms (quasi-static shift). The dynamic shift is due to the emitting and reabsorbing of real photons, by a single atom (dynamic single atomic shift) and between the two atoms (dynamic interatomic shift). The emitting and reabsorbing of virtual and real photons between the two atoms result in the interatomic shift, which does not exist for the one-atom case. The spectra at the long-time limit are calculated. If the distance between the two atoms is shorter than or comparable to the wavelength, the strong coupling between the two atoms splits the spectrum into two peaks, one from the symmetric state and the other from the antisymmetric state. The origin of the red or blue shifts for the symmetric and antisymmetric states mainly lies in the negative or positive interaction energy between the two atoms. In the investigation of the short time evolution, we find the modification of the effective density of states by the interaction between two atoms can modulate the quantum Zeno and quantum anti-Zeno effects in the decays of the symmetric and antisymmetric states.

Optically controlled polarizer using a ladder transition for high speed Stokesmetric Imaging and Quantum Zeno Effect based optical logic.

PubMed

Krishnamurthy, Subramanian; Wang, Y; Tu, Y; Tseng, S; Shahriar, M S

2013-10-21

We demonstrate an optically controlled polarizer at ~1323 nm using a ladder transition in a Rb vapor cell. The lower leg of the 5S(1/2),F = 1->5P(1/2),F = 1,2->6S(1/2),F = 1,2 transitions is excited by a Ti:Sapphire laser locked to a saturated absorption signal, representing the control beam. A tunable fiber laser at ~1323 nm is used to excite the upper leg of the transitions, representing the signal beam. When the control beam is linearly polarized, it produces an excitation of the intermediate level with a particular orientation of the angular momentum. Under ideal conditions, this orientation is transparent to the signal beam if it has the same polarization as the control beam and is absorbed when it is polarized orthogonally. We also present numerical simulations of the system using a comprehensive model which incorporates all the relevant Zeeman sub-levels in the system, and identify means to improve the performance of the polarizer. A novel algorithm to compute the evolution of large scale quantum system enabled us to perform this computation, which may have been considered too cumbersome to carry out previously. We describe how such a polarizer may serve as a key component for high-speed Stokesmetric imaging. We also show how such a polarizer, combined with an optically controlled waveplate, recently demonstrated by us, can be used to realize a high speed optical logic gate by making use of the Quantum Zeno Effect. Finally, we describe how such a logic gate can be realized at an ultra-low power level using a tapered nanofiber embedded in a vapor cell.

Event-triggered consensus tracking of multi-agent systems with Lur'e nonlinear dynamics

NASA Astrophysics Data System (ADS)

Huang, Na; Duan, Zhisheng; Wen, Guanghui; Zhao, Yu

2016-05-01

In this paper, distributed consensus tracking problem for networked Lur'e systems is investigated based on event-triggered information interactions. An event-triggered control algorithm is designed with the advantages of reducing controller update frequency and sensor energy consumption. By using tools of ?-procedure and Lyapunov functional method, some sufficient conditions are derived to guarantee that consensus tracking is achieved under a directed communication topology. Meanwhile, it is shown that Zeno behaviour of triggering time sequences is excluded for the proposed event-triggered rule. Finally, some numerical simulations on coupled Chua's circuits are performed to illustrate the effectiveness of the theoretical algorithms.

Output Consensus of Heterogeneous Linear Multi-Agent Systems by Distributed Event-Triggered/Self-Triggered Strategy.

PubMed

Hu, Wenfeng; Liu, Lu; Feng, Gang

2016-09-02

This paper addresses the output consensus problem of heterogeneous linear multi-agent systems. We first propose a novel distributed event-triggered control scheme. It is shown that, with the proposed control scheme, the output consensus problem can be solved if two matrix equations are satisfied. Then, we further propose a novel self-triggered control scheme, with which continuous monitoring is avoided. By introducing a fixed timer into both event- and self-triggered control schemes, Zeno behavior can be ruled out for each agent. The effectiveness of the event- and self-triggered control schemes is illustrated by an example.

Scientific Objectives of the Critical Viscosity Experiment

NASA Technical Reports Server (NTRS)

Berg, R. F.; Moldover, M. R.

1993-01-01

In microgravity, the Critical Viscosity Experiment will measure the viscosity of xenon 15 times closer to the critical point than is possible on earth. The results are expected to include the first direct observation of the predicted power-law divergence of viscosity in a pure fluid and they will test calculations of the value of the exponent associated with the divergence. The results, when combined with Zeno's decay-rate data, will strengthen the test of mode coupling theory. Without microgravity viscosity data, the Zeno test will require an extrapolation of existing 1-g viscosity data by as much as factor of 100 in reduced temperature. By necessity, the extrapolation would use an incompletely verified theory of viscosity crossover. With the microgravity viscosity data, the reliance on crossover models will be negligible allowing a more reliable extrapolation. During the past year, new theoretical calculations for the viscosity exponent finally achieved consistency with the best experimental data for pure fluids. This report gives the justification for the proposed microgravity Critical Viscosity Experiment in this new context. This report also combines for the first time the best available light scattering data with our recent viscosity data to demonstrate the current status of tests of mode coupling theory.

Distributed convex optimisation with event-triggered communication in networked systems

NASA Astrophysics Data System (ADS)

Liu, Jiayun; Chen, Weisheng

2016-12-01

This paper studies the distributed convex optimisation problem over directed networks. Motivated by practical considerations, we propose a novel distributed zero-gradient-sum optimisation algorithm with event-triggered communication. Therefore, communication and control updates just occur at discrete instants when some predefined condition satisfies. Thus, compared with the time-driven distributed optimisation algorithms, the proposed algorithm has the advantages of less energy consumption and less communication cost. Based on Lyapunov approaches, we show that the proposed algorithm makes the system states asymptotically converge to the solution of the problem exponentially fast and the Zeno behaviour is excluded. Finally, simulation example is given to illustrate the effectiveness of the proposed algorithm.

Neutrino mixing, oscillations and decoherence in astrophysics and cosmology

NASA Astrophysics Data System (ADS)

Ho, Chiu Man

2007-08-01

This thesis focuses on a finite-temperature field-theoretical treatment of neutrino oscillations in hot and dense media. By implementing the methods of real-time non-equilibrium field theory, we study the dynamics of neutrino mixing, oscillations, decoherence and relaxation in astrophysical and cosmological environments. We first study neutrino oscillations in the early universe in the temperature regime prior to the epoch of Big Bang Nucleosynthesis (BBN). The dispersion relations and mixing angles in the medium are found to be helicity-dependent, and a resonance like the Mikheyev-Smirnov- Wolfenstein (MSW) effect is realized. The oscillation time scales are found to be longer near a resonance and shorter for off-resonance high-energy neutrinos. We then investigate the space-time propagation of neutrino wave-packets just before BBN. A phenomenon of " frozen coherence " is found to occur if the longitudinal dispersion catches up with the progressive separation between the mass eigenstates, before the coherence time limit has been reached. However, the transverse dispersion occurs at a much shorter scale than all other possible time scales in the medium, resulting in a large suppression in the transition probabilities from electron-neutrino to muon-neutrino. We also explore the possibility of charged lepton mixing as a consequence of neutrino mixing in the early Universe. We find that charged leptons, like electrons and muons, can mix and oscillate resonantly if there is a large lepton asymmetry in the neutrino sector. We study sterile neutrino production in the early Universe via active-sterile oscillations. We provide a quantum field theoretical reassessment of the quantum Zeno suppression on the active-to-sterile transition probability and its time average. We determine the complete conditions for quantum Zeno suppression. Finally, we examine the interplay between neutrino mixing, oscillations and equilibration in a thermal medium, and the corresponding non-equilibrium dynamics. The equilibrium density matrix is found to be nearly diagonal in the basis of eigenstates of an effective Hamiltonian that includes self-energy corrections in the medium.

Terrorism/Criminalogy/Sociology via Magnetism-Hamiltonian ``Models''?!: Black Swans; What Secrets Lie Buried in Magnetism?; ``Magnetism Will Conquer the Universe?''(Charles Middleton, aka ``His Imperial Majesty The Emperior Ming `The Merciless!!!''

NASA Astrophysics Data System (ADS)

Carrott, Anthony; Siegel, Edward Carl-Ludwig; Hoover, John-Edgar; Ness, Elliott

2013-03-01

Terrorism/Criminalogy//Sociology : non-Linear applied-mathematician (``nose-to-the grindstone / ``gearheadism'') ''modelers'': Worden,, Short, ...criminologists/counter-terrorists/sociologists confront [SIAM Conf. on Nonlinearity, Seattle(12); Canadian Sociology Conf,. Burnaby(12)]. ``The `Sins' of the Fathers Visited Upon the Sons'': Zeno vs Ising vs Heisenberg vs Stoner vs Hubbard vs Siegel ''SODHM''(But NO Y!!!) vs ...??? Magntism and it turn are themselves confronted BY MAGNETISM,via relatively magnetism/metal-insulator conductivity / percolation-phase-transitions critical-phenomena -illiterate non-linear applied-mathematician (nose-to-the-grindstone/ ``gearheadism'')''modelers''. What Secrets Lie Buried in Magnetism?; ``Magnetism Will Conquer the Universe!!!''[Charles Middleton, aka ``His Imperial Majesty The Emperior Ming `The Merciless!!!']'' magnetism-Hamiltonian phase-transitions percolation-``models''!: Zeno(~2350 BCE) to Peter the Pilgrim(1150) to Gilbert(1600) to Faraday(1815-1820) to Tate (1870-1880) to Ewing(1882) hysteresis to Barkhausen(1885) to Curie(1895)-Weiss(1895) to Ising-Lenz(r-space/Localized-Scalar/ Discrete/1911) to Heisenberg(r-space/localized-vector/discrete/1927) to Priesich(1935) to Stoner (electron/k-space/ itinerant-vector/discrete/39) to Stoner-Wohlfarth (technical-magnetism hysteresis /r-space/ itinerant-vector/ discrete/48) to Hubbard-Longuet-Higgins (k-space versus r-space/

Optically controlled waveplate at a telecom wavelength using a ladder transition in Rb atoms for all-optical switching and high speed Stokesmetric imaging.

PubMed

Krishnamurthy, Subramanian; Tu, Y; Wang, Y; Tseng, S; Shahriar, M S

2014-11-17

We demonstrate an optically controlled waveplate at ~1323 nm using the 5S(1/2)-5P(1/2)-6S(1/2) ladder transition in a Rb vapor cell. The lower leg of the transitions represents the control beam, while the upper leg represents the signal beam. We show that we can place the signal beam in any arbitrary polarization state with a suitable choice of polarization of the control beam. Specifically, we demonstrate a differential phase retardance of ~180 degrees between the two circularly polarized components of a linearly polarized signal beam. We also demonstrate that the system can act as a Quarter Wave plate. The optical activity responsible for the phase retardation process is explained in terms of selection rules involving the Zeeman sublevels. As such, the system can be used to realize a fast Stokesmetric imaging system with a speed of ~3 MHz. When implemented using a tapered nano fiber embedded in a vapor cell, this system can be used to realize an ultra-low power all-optical switch as well as a Quantum Zeno Effect based all-optical logic gate by combining it with an optically controlled polarizer, previously demonstrated by us. We present numerical simulations of the system using a comprehensive model which incorporates all the relevant Zeeman sub-levels in the system, using a novel algorithm recently developed by us for efficient computation of the evolution of an arbitrary large scale quantum system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gabuda, S. P.; Kozlova, S. G.; Department of Natural Science, Novosibirsk State University, 2, Pirogova Str., Novosibirsk 630090

Hindering of inversion transitions and a violation of mirror symmetry of the right- and left-handed configurations of diazabizyclooctane (dabco, N{sub 2}C{sub 6}H{sub 12}) enantiomers has been studied with low-temperature adiabatic calorimetry. The dabco molecules were sandwiched in a high-porous layered structure of a metal organic framework (MOF) compound. We show from the data of low-temperature adiabatic calorimetry and {sup 1}H NMR spin relaxation method that hindering of inversion transitions of dabco molecules cannot be associated with the influence of the intracrystalline self-consistent molecular field as a continuously monitoring environment within the quantum Zeno effect. In addition, lack of another manifestationmore » of this effect associated with the collisional suppression of the inversion transitions in MOF samples impregnated by helium has been shown. These results lead to the conclusion that chiral polarization is related to the fundamental effect of parity nonconservation.« less

Probabilistic direct counterfactual quantum communication

NASA Astrophysics Data System (ADS)

Zhang, Sheng

2017-02-01

It is striking that the quantum Zeno effect can be used to launch a direct counterfactual communication between two spatially separated parties, Alice and Bob. So far, existing protocols of this type only provide a deterministic counterfactual communication service. However, this counterfactuality should be payed at a price. Firstly, the transmission time is much longer than a classical transmission costs. Secondly, the chained-cycle structure makes them more sensitive to channel noises. Here, we extend the idea of counterfactual communication, and present a probabilistic-counterfactual quantum communication protocol, which is proved to have advantages over the deterministic ones. Moreover, the presented protocol could evolve to a deterministic one solely by adjusting the parameters of the beam splitters. Project supported by the National Natural Science Foundation of China (Grant No. 61300203).

The Experimental Demonstration of High Efficiency Interaction-free Measurement for Quantum Counterfactual-like Communication.

PubMed

Liu, Chao; Liu, Jinhong; Zhang, Junxiang; Zhu, Shiyao

2017-09-07

We present an interaction-free measurement with quantum Zeno effect and a high efficiency η = 74.6% ± 0.15%. As a proof-of-principle demonstration, this measurement can be used to implement a quantum counterfactual-like communication protocol. Instead of a single photon state, we use a coherent light as the input source and show that the output agrees with the proposed quantum counterfactual communication protocol according to Salih et al. Although the counterfactuality is not achieved due to the presence of a few photons in the public channel, we show that the signal light is nearly absent in the public channel, which exhibits a proof-of-principle quantum counterfactual-like property of communication.

Modelling and properties of a nonlinear autonomous switching system in fed-batch culture of glycerol

NASA Astrophysics Data System (ADS)

Wang, Juan; Sun, Qingying; Feng, Enmin

2012-11-01

A nonlinear autonomous switching system is proposed to describe the coupled fed-batch fermentation with the pH as the feedback parameter. We prove the non-Zeno behaviors of the switching system and some basic properties of its solution, including the existence, uniqueness, boundedness and regularity. Numerical simulation is also carried out, which reveals that the proposed system can describe the factual fermentation process properly.

Temporal nonlocality in bistable perception

NASA Astrophysics Data System (ADS)

Atmanspacher, Harald; Filk, Thomas

2012-12-01

A novel conceptual framework for theoretical psychology is presented and illustrated for the example of bistable perception. A basic formal feature of this framework is the non-commutativity of operations acting on mental states. A corresponding model for the bistable perception of ambiguous stimuli, the Necker-Zeno model, is sketched and some empirical evidence for it so far is described. It is discussed how a temporal nonlocality of mental states, predicted by the model, can be understood and tested.

High-efficiency interaction-free measurement with an unbalanced Mach–Zehnder interferometer

NASA Astrophysics Data System (ADS)

Chao, Liu; Jinhong, Liu; Junxiang, Zhang; Shiyao, Zhu

2018-06-01

The presence of an object can be detected without the absorption of photons in an interaction-free measurement (IFM) system based on the Zeno effect in chained Mach–Zehnder interferometers (MZIs). In this paper, we propose a scheme with an unbalanced MZI to perform the transmission of two frequency components of input light simultaneously. The two components are separated at two output ports of the MZI, achieving a high probability of asserting the absence of the object. The two final outputs of the MZI can also be extended to perform special information processing via IFM. As a result, this proposal contributes to the improvement of efficiency in interaction-free measurements with a very small number of interferometers for potential practical implementations of quantum information technology.

Experimental Realization of High-Efficiency Counterfactual Computation.

PubMed

Kong, Fei; Ju, Chenyong; Huang, Pu; Wang, Pengfei; Kong, Xi; Shi, Fazhan; Jiang, Liang; Du, Jiangfeng

2015-08-21

Counterfactual computation (CFC) exemplifies the fascinating quantum process by which the result of a computation may be learned without actually running the computer. In previous experimental studies, the counterfactual efficiency is limited to below 50%. Here we report an experimental realization of the generalized CFC protocol, in which the counterfactual efficiency can break the 50% limit and even approach unity in principle. The experiment is performed with the spins of a negatively charged nitrogen-vacancy color center in diamond. Taking advantage of the quantum Zeno effect, the computer can remain in the not-running subspace due to the frequent projection by the environment, while the computation result can be revealed by final detection. The counterfactual efficiency up to 85% has been demonstrated in our experiment, which opens the possibility of many exciting applications of CFC, such as high-efficiency quantum integration and imaging.

Experimental Realization of High-Efficiency Counterfactual Computation

NASA Astrophysics Data System (ADS)

Kong, Fei; Ju, Chenyong; Huang, Pu; Wang, Pengfei; Kong, Xi; Shi, Fazhan; Jiang, Liang; Du, Jiangfeng

2015-08-01

Counterfactual computation (CFC) exemplifies the fascinating quantum process by which the result of a computation may be learned without actually running the computer. In previous experimental studies, the counterfactual efficiency is limited to below 50%. Here we report an experimental realization of the generalized CFC protocol, in which the counterfactual efficiency can break the 50% limit and even approach unity in principle. The experiment is performed with the spins of a negatively charged nitrogen-vacancy color center in diamond. Taking advantage of the quantum Zeno effect, the computer can remain in the not-running subspace due to the frequent projection by the environment, while the computation result can be revealed by final detection. The counterfactual efficiency up to 85% has been demonstrated in our experiment, which opens the possibility of many exciting applications of CFC, such as high-efficiency quantum integration and imaging.

Similarity law and critical properties in ionic systems.

NASA Astrophysics Data System (ADS)

Desgranges, Caroline; Delhommelle, Jerome

2017-11-01

Using molecular simulations, we determine the locus of ideal compressibility, or Zeno line, for a series of ionic compounds. We find that the shape of this thermodynamic contour follows a linear law, leading to the determination of the Boyle parameters. We also show that a similarity law, based on the Boyle parameters, yields accurate critical data when compared to the experiment. Furthermore, we show that the Boyle density scales linearly with the size-asymmetry, providing a direct route to establish a correspondence between the thermodynamic properties of different ionic compounds.

The case of escape probability as linear in short time

NASA Astrophysics Data System (ADS)

Marchewka, A.; Schuss, Z.

2018-02-01

We derive rigorously the short-time escape probability of a quantum particle from its compactly supported initial state, which has a discontinuous derivative at the boundary of the support. We show that this probability is linear in time, which seems to be a new result. The novelty of our calculation is the inclusion of the boundary layer of the propagated wave function formed outside the initial support. This result has applications to the decay law of the particle, to the Zeno behaviour, quantum absorption, time of arrival, quantum measurements, and more.

Automation of experiments at Dubna Gas-Filled Recoil Separator

NASA Astrophysics Data System (ADS)

Tsyganov, Yu. S.

2016-01-01

Approaches to solving the problems of automation of basic processes in long-term experiments in heavy ion beams of the Dubna Gas-Filled Recoil Separator (DGFRS) facility are considered. Approaches in the field of spectrometry, both of rare α decays of superheavy nuclei and those for constructing monitoring systems to provide accident-free experiment running with highly radioactive targets and recording basic parameters of experiment, are described. The specific features of Double Side Silicon Strip Detectors (DSSSDs) are considered, special attention is paid to the role of boundary effects of neighboring p-n transitions in the "active correlations" method. An example of an off-beam experiment attempting to observe Zeno effect is briefly considered. Basic examples for nuclear reactions of complete fusion at 48Ca ion beams of U-400 cyclotron (LNR, JINR) are given. A scenario of development of the "active correlations" method for the case of very high intensity beams of heavy ions at promising accelerators of LNR, JINR, is presented.

Entropy of the information retrieved from black holes

NASA Astrophysics Data System (ADS)

Mersini-Houghton, Laura

2016-07-01

The retrieval of black hole information was recently presented in two interesting proposals in the ‘Hawking Radiation’ conference: a revised version by Hooft of a proposal he initially suggested 20 years ago and, a new proposal by Hawking. Both proposals address the problem of black hole information loss at the classical level and derive an expression for the scattering matrix. The former uses gravitation back reaction of incoming particles that imprints its information on the outgoing modes. The latter uses supertranslation symmetry of horizons to relate a phase delay of the outgoing wave packet compared to their incoming wave partners. The difficulty in both proposals is that the entropy obtained from them appears to be infinite. By including quantum effects into the Hawking and Hooft’s proposals, I show that a subtlety arising from the inescapable measurement process, the quantum Zeno effect, not only tames divergences but it actually recovers the correct 1/4 of the area Bekenstein-Hawking entropy law of black holes.

Generation of three-qubit Greenberger-Horne-Zeilinger state of superconducting qubits via transitionless quantum driving

NASA Astrophysics Data System (ADS)

Zhang, Xu; Chen, Ye-Hong; Wu, Qi-Cheng; Shi, Zhi-Cheng; Song, Jie; Xia, Yan

2017-01-01

We present an efficient scheme to quickly generate three-qubit Greenberger-Horne-Zeilinger (GHZ) states by using three superconducting qubits (SQs) separated by two coplanar waveguide resonators (CPWRs) capacitively. The scheme is based on quantum Zeno dynamics and the approach of transitionless quantum driving to construct shortcuts to adiabatic passage. In order to highlight the advantages, we compare the present scheme with the traditional one with adiabatic passage. The comparison result shows the shortcut scheme is closely related to the adiabatic scheme but is better than it. Moreover, we discuss the influence of various decoherences with numerical simulation. The result proves that the present scheme is less sensitive to the energy relaxation, the decay of CPWRs and the deviations of the experimental parameters the same as the adiabatic passage. However, the shortcut scheme is effective and robust against the dephasing of SQs in comparison with the adiabatic scheme.

Exponential Synchronization of Networked Chaotic Delayed Neural Network by a Hybrid Event Trigger Scheme.

PubMed

Fei, Zhongyang; Guan, Chaoxu; Gao, Huijun; Zhongyang Fei; Chaoxu Guan; Huijun Gao; Fei, Zhongyang; Guan, Chaoxu; Gao, Huijun

2018-06-01

This paper is concerned with the exponential synchronization for master-slave chaotic delayed neural network with event trigger control scheme. The model is established on a network control framework, where both external disturbance and network-induced delay are taken into consideration. The desired aim is to synchronize the master and slave systems with limited communication capacity and network bandwidth. In order to save the network resource, we adopt a hybrid event trigger approach, which not only reduces the data package sending out, but also gets rid of the Zeno phenomenon. By using an appropriate Lyapunov functional, a sufficient criterion for the stability is proposed for the error system with extended ( , , )-dissipativity performance index. Moreover, hybrid event trigger scheme and controller are codesigned for network-based delayed neural network to guarantee the exponential synchronization between the master and slave systems. The effectiveness and potential of the proposed results are demonstrated through a numerical example.

Hydrodynamic radius fluctuations in model DNA-grafted nanoparticles

NASA Astrophysics Data System (ADS)

Vargas-Lara, Fernando; Starr, Francis W.; Douglas, Jack F.

2016-05-01

We utilize molecular dynamics simulations (MD) and the path-integration program ZENO to quantify hydrodynamic radius (Rh) fluctuations of spherical symmetric gold nanoparticles (NPs) decorated with single-stranded DNA chains (ssDNA). These results are relevant to understanding fluctuation-induced interactions among these NPs and macromolecules such as proteins. In particular, we explore the effect of varying the ssDNA-grafted NPs structural parameters, such as the chain length (L), chain persistence length (lp), NP core size (R), and the number of chains (N) attached to the nanoparticle core. We determine Rh fluctuations by calculating its standard deviation (σRh) of an ensemble of ssDNA-grafted NPs configurations generated by MD. For the parameter space explored in this manuscript, σR h shows a peak value as a function of N, the amplitude of which depends on L, lp and R, while the broadness depends on R.

Recent advances in the UltraScan SOlution MOdeller (US-SOMO) hydrodynamic and small-angle scattering data analysis and simulation suite.

PubMed

Brookes, Emre; Rocco, Mattia

2018-03-28

The UltraScan SOlution MOdeller (US-SOMO) is a comprehensive, public domain, open-source suite of computer programs centred on hydrodynamic modelling and small-angle scattering (SAS) data analysis and simulation. We describe here the advances that have been implemented since its last official release (#3087, 2017), which are available from release #3141 for Windows, Linux and Mac operating systems. A major effort has been the transition from the legacy Qt3 cross platform software development and user interface library to the modern Qt5 release. Apart from improved graphical support, this has allowed the direct implementation of the newest, almost two-orders of magnitude faster version of the ZENO hydrodynamic computation algorithm for all operating systems. Coupled with the SoMo-generated bead models with overlaps, ZENO provides the most accurate translational friction computations from atomic-level structures available (Rocco and Byron Eur Biophys J 44:417-431, 2015a), with computational times comparable with or faster than those of other methods. In addition, it has allowed us to introduce the direct representation of each atom in a structure as a (hydrated) bead, opening interesting new modelling possibilities. In the small-angle scattering (SAS) part of the suite, an indirect Fourier transform Bayesian algorithm has been implemented for the computation of the pairwise distance distribution function from SAS data. Finally, the SAS HPLC module, recently upgraded with improved baseline correction and Gaussian decomposition of not baseline-resolved peaks and with advanced statistical evaluation tools (Brookes et al. J Appl Cryst 49:1827-1841, 2016), now allows automatic top-peak frame selection and averaging.

Production of a sterile species via active-sterile mixing: An exactly solvable model

NASA Astrophysics Data System (ADS)

Boyanovsky, D.

2007-11-01

The production of a sterile species via active-sterile mixing in a thermal medium is studied in an exactly solvable model. The exact time evolution of the sterile distribution function is determined by the dispersion relations and damping rates Γ1,2 for the quasiparticle modes. These depend on γ˜=Γaa/2ΔE, with Γaa the interaction rate of the active species in absence of mixing and ΔE the oscillation frequency in the medium without damping. γ˜≪1, γ˜≫1 describe the weak and strong damping limits, respectively. For γ˜≪1, Γ1=Γaacos⁡2θm; Γ2=Γaasin⁡2θm where θm is the mixing angle in the medium and the sterile distribution function does not obey a simple rate equation. For γ˜≫1, Γ1=Γaa and Γ2=Γaasin⁡22θm/4γ˜2, is the sterile production rate. In this regime sterile production is suppressed and the oscillation frequency vanishes at an Mikheyev-Smirnov-Wolfenstein (MSW) resonance, with a breakdown of adiabaticity. These are consequences of quantum Zeno suppression. For active neutrinos with standard model interactions the strong damping limit is only available near an MSW resonance if sin⁡2θ≪αw with θ the vacuum mixing angle. The full set of quantum kinetic equations for sterile production for arbitrary γ˜ are obtained from the quantum master equation. Cosmological resonant sterile neutrino production is quantum Zeno suppressed relieving potential uncertainties associated with the QCD phase transition.

Extracting Work from Quantum Measurement in Maxwell's Demon Engines

NASA Astrophysics Data System (ADS)

Elouard, Cyril; Herrera-Martí, David; Huard, Benjamin; Auffèves, Alexia

2017-06-01

The essence of both classical and quantum engines is to extract useful energy (work) from stochastic energy sources, e.g., thermal baths. In Maxwell's demon engines, work extraction is assisted by a feedback control based on measurements performed by a demon, whose memory is erased at some nonzero energy cost. Here we propose a new type of quantum Maxwell's demon engine where work is directly extracted from the measurement channel, such that no heat bath is required. We show that in the Zeno regime of frequent measurements, memory erasure costs eventually vanish. Our findings provide a new paradigm to analyze quantum heat engines and work extraction in the quantum world.

Encoding quantum information in a stabilized manifold of a superconducting cavity

NASA Astrophysics Data System (ADS)

Touzard, S.; Leghtas, Z.; Mundhada, S. O.; Axline, C.; Reagor, M.; Chou, K.; Blumoff, J.; Sliwa, K. M.; Shankar, S.; Frunzio, L.; Schoelkopf, R. J.; Mirrahimi, M.; Devoret, M. H.

In a superconducting Josephson circuit architecture, we activate a multi-photon process between two modes by applying microwave drives at specific frequencies. This creates a pairwise exchange of photons between a high-Q cavity and the environment. The resulting open dynamical system develops a two-dimensional quasi-energy ground state manifold. Can we encode, protect and manipulate quantum information in this manifold? We experimentally investigate the convergence and escape rates in and out of this confined subspace. Finally, using quantum Zeno dynamics, we aim to perform gates which maintain the state in the protected manifold at all times. Work supported by: ARO, ONR, AFOSR and YINQE.

Dynamical decoupling of local transverse random telegraph noise in a two-qubit gate

NASA Astrophysics Data System (ADS)

D'Arrigo, A.; Falci, G.; Paladino, E.

2015-10-01

Achieving high-fidelity universal two-qubit gates is a central requisite of any implementation of quantum information processing. The presence of spurious fluctuators of various physical origin represents a limiting factor for superconducting nanodevices. Operating qubits at optimal points, where the qubit-fluctuator interaction is transverse with respect to the single qubit Hamiltonian, considerably improved single qubit gates. Further enhancement has been achieved by dynamical decoupling (DD). In this article we investigate DD of transverse random telegraph noise acting locally on each of the qubits forming an entangling gate. Our analysis is based on the exact numerical solution of the stochastic Schrödinger equation. We evaluate the gate error under local periodic, Carr-Purcell and Uhrig DD sequences. We find that a threshold value of the number, n, of pulses exists above which the gate error decreases with a sequence-specific power-law dependence on n. Below threshold, DD may even increase the error with respect to the unconditioned evolution, a behaviour reminiscent of the anti-Zeno effect.

Separation and conversion dynamics of nuclear-spin isomers of gaseous methanol

PubMed Central

Sun, Zhen-Dong; Ge, Meihua; Zheng, Yujun

2015-01-01

All symmetrical molecules with non-zero nuclear spin exist in nature as nuclear-spin isomers (NSIs). However, owing to the lack of experimental information, knowledge is rare about interconversions of NSIs of gaseous molecules with torsional symmetry. Here we report our separation and conversion observations on NSI-torsion-specific transition systems of gaseous methanol from a light-induced drift experiment involving partially spatial separation of the ortho and para isomers. We find that vibrationally excited molecules of the methanol spin isomer have a smaller collision cross-section than their ground-state counterparts. Interconversion of the enriched ortho isomer with the para isomer, which is generally considered improbable, has been quantitatively studied by sensitive detections of the spectral intensities. Rather counterintuitively, this reveals that the interconversion is inhibited with increasing pressure. Our results suggest that the spin conversion mechanism in methanol is via a quantum relaxation process with the quantum Zeno effect induced by molecular collisions. PMID:25880882

Fast Implementation of Quantum Phase Gates and Creation of Cluster States via Transitionless Quantum Driving

NASA Astrophysics Data System (ADS)

Zhang, Chun-Ling; Liu, Wen-Wu

2018-05-01

In this paper, combining transitionless quantum driving and quantum Zeno dynamics, we propose an efficient scheme to fast implement a two-qubit quantum phase gate which can be used to generate cluster state of atoms trapped in distant cavities. The influence of various of various error sources including spontaneous emission and photon loss on the fidelity is analyzed via numerical simulation. The results show that this scheme not only takes less time than adiabatic scheme but also is not sensitive to both error sources. Additionally, a creation of N-atom cluster states is put forward as a typical example of the applications of the phase gates.

Lognormal-like statistics of a stochastic squeeze process

NASA Astrophysics Data System (ADS)

Shapira, Dekel; Cohen, Doron

2017-10-01

We analyze the full statistics of a stochastic squeeze process. The model's two parameters are the bare stretching rate w and the angular diffusion coefficient D . We carry out an exact analysis to determine the drift and the diffusion coefficient of log(r ) , where r is the radial coordinate. The results go beyond the heuristic lognormal description that is implied by the central limit theorem. Contrary to the common "quantum Zeno" approximation, the radial diffusion is not simply Dr=(1 /8 ) w2/D but has a nonmonotonic dependence on w /D . Furthermore, the calculation of the radial moments is dominated by the far non-Gaussian tails of the log(r ) distribution.

Centralized and decentralized global outer-synchronization of asymmetric recurrent time-varying neural network by data-sampling.

PubMed

Lu, Wenlian; Zheng, Ren; Chen, Tianping

2016-03-01

In this paper, we discuss outer-synchronization of the asymmetrically connected recurrent time-varying neural networks. By using both centralized and decentralized discretization data sampling principles, we derive several sufficient conditions based on three vector norms to guarantee that the difference of any two trajectories starting from different initial values of the neural network converges to zero. The lower bounds of the common time intervals between data samples in centralized and decentralized principles are proved to be positive, which guarantees exclusion of Zeno behavior. A numerical example is provided to illustrate the efficiency of the theoretical results. Copyright © 2015 Elsevier Ltd. All rights reserved.

Shortcuts to adiabatic passage for fast generation of Greenberger-Horne-Zeilinger states by transitionless quantum driving.

PubMed

Chen, Ye-Hong; Xia, Yan; Song, Jie; Chen, Qing-Qin

2015-10-28

Berry's approach on "transitionless quantum driving" shows how to set a Hamiltonian which drives the dynamics of a system along instantaneous eigenstates of a reference Hamiltonian to reproduce the same final result of an adiabatic process in a shorter time. In this paper, motivated by transitionless quantum driving, we construct shortcuts to adiabatic passage in a three-atom system to create the Greenberger-Horne-Zeilinger states with the help of quantum Zeno dynamics and of non-resonant lasers. The influence of various decoherence processes is discussed by numerical simulation and the result proves that the scheme is fast and robust against decoherence and operational imperfection.

Fast generating Greenberger-Horne-Zeilinger state via iterative interaction pictures

NASA Astrophysics Data System (ADS)

Huang, Bi-Hua; Chen, Ye-Hong; Wu, Qi-Cheng; Song, Jie; Xia, Yan

2016-10-01

We delve a little deeper into the construction of shortcuts to adiabatic passage for three-level systems by iterative interaction picture (multiple Schrödinger dynamics). As an application example, we use the deduced iterative based shortcuts to rapidly generate the Greenberger-Horne-Zeilinger (GHZ) state in a three-atom system with the help of quantum Zeno dynamics. Numerical simulation shows the dynamics designed by the iterative picture method is physically feasible and the shortcut scheme performs much better than that using the conventional adiabatic passage techniques. Also, the influences of various decoherence processes are discussed by numerical simulation and the results prove that the scheme is fast and robust against decoherence and operational imperfection.

Counterfactual quantum computation through quantum interrogation

NASA Astrophysics Data System (ADS)

Hosten, Onur; Rakher, Matthew T.; Barreiro, Julio T.; Peters, Nicholas A.; Kwiat, Paul G.

2006-02-01

The logic underlying the coherent nature of quantum information processing often deviates from intuitive reasoning, leading to surprising effects. Counterfactual computation constitutes a striking example: the potential outcome of a quantum computation can be inferred, even if the computer is not run. Relying on similar arguments to interaction-free measurements (or quantum interrogation), counterfactual computation is accomplished by putting the computer in a superposition of `running' and `not running' states, and then interfering the two histories. Conditional on the as-yet-unknown outcome of the computation, it is sometimes possible to counterfactually infer information about the solution. Here we demonstrate counterfactual computation, implementing Grover's search algorithm with an all-optical approach. It was believed that the overall probability of such counterfactual inference is intrinsically limited, so that it could not perform better on average than random guesses. However, using a novel `chained' version of the quantum Zeno effect, we show how to boost the counterfactual inference probability to unity, thereby beating the random guessing limit. Our methods are general and apply to any physical system, as illustrated by a discussion of trapped-ion systems. Finally, we briefly show that, in certain circumstances, counterfactual computation can eliminate errors induced by decoherence.

Quantum measurement-induced dynamics of many-body ultracold bosonic and fermionic systems in optical lattices

NASA Astrophysics Data System (ADS)

Mazzucchi, Gabriel; Kozlowski, Wojciech; Caballero-Benitez, Santiago F.; Elliott, Thomas J.; Mekhov, Igor B.

2016-02-01

Trapping ultracold atoms in optical lattices enabled numerous breakthroughs uniting several disciplines. Coupling these systems to quantized light leads to a plethora of new phenomena and has opened up a new field of study. Here we introduce an unusual additional source of competition in a many-body strongly correlated system: We prove that quantum backaction of global measurement is able to efficiently compete with intrinsic short-range dynamics of an atomic system. The competition becomes possible due to the ability to change the spatial profile of a global measurement at a microscopic scale comparable to the lattice period without the need of single site addressing. In coherence with a general physical concept, where new competitions typically lead to new phenomena, we demonstrate nontrivial dynamical effects such as large-scale multimode oscillations, long-range entanglement, and correlated tunneling, as well as selective suppression and enhancement of dynamical processes beyond the projective limit of the quantum Zeno effect. We demonstrate both the breakup and protection of strongly interacting fermion pairs by measurement. Such a quantum optical approach introduces into many-body physics novel processes, objects, and methods of quantum engineering, including the design of many-body entangled environments for open systems.

Decoherence control mechanisms of a charged magneto-oscillator in contact with different environments

NASA Astrophysics Data System (ADS)

Rajesh, Asam; Bandyopadhyay, Malay; Jayannavar, Arun M.

2017-12-01

In this work, we consider two different techniques based on reservoir engineering process and quantum Zeno control method to analyze the decoherence control mechanism of a charged magneto-oscillator in contact with different type of environment. Our analysis reveals that both the control mechanisms are very much sensitive on the details of different environmental spectrum (J (ω)), and also on different system and reservoir parameters, e.g., external magnetic field (rc), confinement length (r0), temperature (T), cut-off frequency of reservoir spectrum (ωcut), and measurement interval (τ). We also demonstrate the manipulation scheme of the continuous passage from decay suppression to decay acceleration by tuning the above mentioned system or reservoir parameters, e.g., rc, r0, T and τ.

Coherent Oscillations inside a Quantum Manifold Stabilized by Dissipation

NASA Astrophysics Data System (ADS)

Touzard, S.; Grimm, A.; Leghtas, Z.; Mundhada, S. O.; Reinhold, P.; Axline, C.; Reagor, M.; Chou, K.; Blumoff, J.; Sliwa, K. M.; Shankar, S.; Frunzio, L.; Schoelkopf, R. J.; Mirrahimi, M.; Devoret, M. H.

2018-04-01

Manipulating the state of a logical quantum bit (qubit) usually comes at the expense of exposing it to decoherence. Fault-tolerant quantum computing tackles this problem by manipulating quantum information within a stable manifold of a larger Hilbert space, whose symmetries restrict the number of independent errors. The remaining errors do not affect the quantum computation and are correctable after the fact. Here we implement the autonomous stabilization of an encoding manifold spanned by Schrödinger cat states in a superconducting cavity. We show Zeno-driven coherent oscillations between these states analogous to the Rabi rotation of a qubit protected against phase flips. Such gates are compatible with quantum error correction and hence are crucial for fault-tolerant logical qubits.

Topological properties of a curved spacetime

NASA Astrophysics Data System (ADS)

Agrawal, Gunjan; Shrivastava, Sampada; Godani, Nisha; Sinha, Soami Pyari

2017-12-01

The present paper aims at the study of a topology on Lorentzian manifolds, defined by Göbel [4] using the ideas of Zeeman [16]. Observing that on the Minkowski space it is the same as Zeeman's time topology, it has been found that a Lorentzian manifold with this topology is path connected, nonfirst countable and nonsimply connected while the Minkowski space with time topology is, in addition nonregular and separable. Furthermore, using the notion of Zeno sequences it is obtained that a compact set does not contain a nonempty open set and that a set is compact if and only if each of its infinite subsets has a limit point if and only if each of its sequences has a convergent subsequence.

Interaction-Free Effects Between Distant Atoms

NASA Astrophysics Data System (ADS)

Aharonov, Yakir; Cohen, Eliahu; Elitzur, Avshalom C.; Smolin, Lee

2018-01-01

A Gedanken experiment is presented where an excited and a ground-state atom are positioned such that, within the former's half-life time, they exchange a photon with 50% probability. A measurement of their energy state will therefore indicate in 50% of the cases that no photon was exchanged. Yet other measurements would reveal that, by the mere possibility of exchange, the two atoms have become entangled. Consequently, the "no exchange" result, apparently precluding entanglement, is non-locally established between the atoms by this very entanglement. This quantum-mechanical version of the ancient Liar Paradox can be realized with already existing transmission schemes, with the addition of Bell's theorem applied to the no-exchange cases. Under appropriate probabilities, the initially-excited atom, still excited, can be entangled with additional atoms time and again, or alternatively, exert multipartite nonlocal correlations in an interaction free manner. When densely repeated several times, this result also gives rise to the Quantum Zeno effect, again exerted between distant atoms without photon exchange. We discuss these experiments as variants of interaction-free-measurement, now generalized for both spatial and temporal uncertainties. We next employ weak measurements for elucidating the paradox. Interpretational issues are discussed in the conclusion, and a resolution is offered within the Two-State Vector Formalism and its new Heisenberg framework.

Interaction-Free Effects Between Distant Atoms

NASA Astrophysics Data System (ADS)

Aharonov, Yakir; Cohen, Eliahu; Elitzur, Avshalom C.; Smolin, Lee

2017-12-01

A Gedanken experiment is presented where an excited and a ground-state atom are positioned such that, within the former's half-life time, they exchange a photon with 50% probability. A measurement of their energy state will therefore indicate in 50% of the cases that no photon was exchanged. Yet other measurements would reveal that, by the mere possibility of exchange, the two atoms have become entangled. Consequently, the "no exchange" result, apparently precluding entanglement, is non-locally established between the atoms by this very entanglement. This quantum-mechanical version of the ancient Liar Paradox can be realized with already existing transmission schemes, with the addition of Bell's theorem applied to the no-exchange cases. Under appropriate probabilities, the initially-excited atom, still excited, can be entangled with additional atoms time and again, or alternatively, exert multipartite nonlocal correlations in an interaction free manner. When densely repeated several times, this result also gives rise to the Quantum Zeno effect, again exerted between distant atoms without photon exchange. We discuss these experiments as variants of interaction-free-measurement, now generalized for both spatial and temporal uncertainties. We next employ weak measurements for elucidating the paradox. Interpretational issues are discussed in the conclusion, and a resolution is offered within the Two-State Vector Formalism and its new Heisenberg framework.

Electronic Maxwell demon in the coherent strong-coupling regime

NASA Astrophysics Data System (ADS)

Schaller, Gernot; Cerrillo, Javier; Engelhardt, Georg; Strasberg, Philipp

2018-05-01

We consider an external feedback control loop implementing the action of a Maxwell demon. Applying control actions that are conditioned on measurement outcomes, the demon may transport electrons against a bias voltage and thereby effectively converts information into electric power. While the underlying model—a feedback-controlled quantum dot that is coupled to two electronic leads—is well explored in the limit of small tunnel couplings, we can address the strong-coupling regime with a fermionic reaction-coordinate mapping. This exact mapping transforms the setup into a serial triple quantum dot coupled to two leads. We find that a continuous projective measurement of the central dot occupation would lead to a complete suppression of electronic transport due to the quantum Zeno effect. In contrast, by using a microscopic detector model we can implement a weak measurement, which allows for closure of the control loop without transport blockade. Then, in the weak-coupling regime, the energy flows associated with the feedback loop are negligible, and dominantly the information gained in the measurement induces a bound for the generated electric power. In the strong coupling limit, the protocol may require more energy for operating the control loop than electric power produced, such that the whole device is no longer information dominated and can thus not be interpreted as a Maxwell demon.

Event-triggered synchronization for reaction-diffusion complex networks via random sampling

NASA Astrophysics Data System (ADS)

Dong, Tao; Wang, Aijuan; Zhu, Huiyun; Liao, Xiaofeng

2018-04-01

In this paper, the synchronization problem of the reaction-diffusion complex networks (RDCNs) with Dirichlet boundary conditions is considered, where the data is sampled randomly. An event-triggered controller based on the sampled data is proposed, which can reduce the number of controller and the communication load. Under this strategy, the synchronization problem of the diffusion complex network is equivalently converted to the stability of a of reaction-diffusion complex dynamical systems with time delay. By using the matrix inequality technique and Lyapunov method, the synchronization conditions of the RDCNs are derived, which are dependent on the diffusion term. Moreover, it is found the proposed control strategy can get rid of the Zeno behavior naturally. Finally, a numerical example is given to verify the obtained results.

Continuous quantum error correction for non-Markovian decoherence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oreshkov, Ognyan; Brun, Todd A.; Communication Sciences Institute, University of Southern California, Los Angeles, California 90089

2007-08-15

We study the effect of continuous quantum error correction in the case where each qubit in a codeword is subject to a general Hamiltonian interaction with an independent bath. We first consider the scheme in the case of a trivial single-qubit code, which provides useful insights into the workings of continuous error correction and the difference between Markovian and non-Markovian decoherence. We then study the model of a bit-flip code with each qubit coupled to an independent bath qubit and subject to continuous correction, and find its solution. We show that for sufficiently large error-correction rates, the encoded state approximatelymore » follows an evolution of the type of a single decohering qubit, but with an effectively decreased coupling constant. The factor by which the coupling constant is decreased scales quadratically with the error-correction rate. This is compared to the case of Markovian noise, where the decoherence rate is effectively decreased by a factor which scales only linearly with the rate of error correction. The quadratic enhancement depends on the existence of a Zeno regime in the Hamiltonian evolution which is absent in purely Markovian dynamics. We analyze the range of validity of this result and identify two relevant time scales. Finally, we extend the result to more general codes and argue that the performance of continuous error correction will exhibit the same qualitative characteristics.« less

Quantum Counterfactual Information Transmission Without a Weak Trace

NASA Astrophysics Data System (ADS)

Arvidsson Shukur, David; Barnes, Crispin

The classical theories of communication rely on the assumption that there has to be a flow of particles from Bob to Alice in order for him to send a message to her. We have developed a quantum protocol that allows Alice to perceive Bob's message ``counterfactually''. That is, without Alice receiving any particles that have interacted with Bob. By utilising a setup built on results from interaction-free measurements and the quantum Zeno effect, we outline a communication protocol in which the information travels in the opposite direction of the emitted particles. In comparison to previous attempts on such protocols, this one is such that a weak measurement at the message source would not leave a weak trace that could be detected by Alice's receiver. Whilst some interaction-free schemes require a large number of carefully aligned beam-splitters, our protocol is realisable with two or more beam-splitters. Furthermore, we outline how Alice's obtained classical Fisher information between a weak variable at Bob's laboratory is negligible in our scheme. We demonstrate this protocol by numerically solving the time-dependent Schrödinger Equation (TDSE) for a Hamiltonian that implements this quantum counterfactual phenomenon.

STS-75 Flight Day 1

NASA Technical Reports Server (NTRS)

1996-01-01

On this first day of the STS-75 mission, the flight crew, Cmdr. Andrew Allen, Pilot Scott Horowitz, Payload Cmdr. Franklin Chang-Diaz, Payload Specialist Umberto Guidoni (Italy), and Mission Specialists Jeffrey Hoffman, Maurizio Cheli (ESA) and Claude Nicollier (ESA), were shown performing pre-launch and launching activities. This international space mission's primary objective is the deployment of the Tethered Satellite System Reflight (TSS-1R) to a 12 mile length from the shuttle, a variety of experiments, and the satellite retrieval. These experiments include: Research on Orbital Plasma Electrodynamics (ROPE); TSS Deployer Core Equipment and Satellite Core Equipment (DCORE/SCORE); Research on Electrodynamic Tether Effects (RETE); Magnetic Field Experiments for TSS Missions (TEMAG); Shuttle Electrodynamic Tether Systems (SETS); Shuttle Potential and Return Electron Experiment (SPREE); Tether Optical Phenomena Experiment (TOP); and Observations at the Earth's Surface of Electromagnetic Emissions by TSS (OESSE). The mission's secondary objectives were those experiments found in the United States Microgravity Payload-3 (USMP-3), which include: Advanced Automated Directional Solidification Furnace (AADSF); Material pour l'Etude des Phenomenes Interessant la Solidification sur Terre et en Orbite (MEPHISTO); Space Acceleration Measurement System (SAMS); Orbital Acceleration Research Experiment (OARE); Critical Fluid Scattering Experiment (ZENO); and Isothermal Dendritic Growth Experiment (IDGE).

Exploring Quantum Dynamics of Continuous Measurement with a Superconducting Qubit

NASA Astrophysics Data System (ADS)

Jadbabaie, Arian; Forouzani, Neda; Tan, Dian; Murch, Kater

Weak measurements obtain partial information about a quantum state with minimal backaction. This enables state tracking without immediate collapse to eigenstates, of interest to both experimental and theoretical physics. State tomography and continuous weak measurements may be used to reconstruct the evolution of a single system, known as a quantum trajectory. We examine experimental trajectories of a two-level system at varied measurement strengths with constant unitary drive. Our analysis is applied to a transmon qubit dispersively coupled to a 3D microwave cavity in the circuit QED architecture. The weakly coupled cavity acts as pointer system for QND measurements in the qubit's energy basis. Our results indicate a marked difference in state purity between two approaches for trajectory reconstruction: the Bayesian and Stochastic Master Equation (SME) formalisms. Further, we observe the transition from diffusive to jump-like trajectories, state purity evolution, and a novel, tilted form of the Quantum Zeno effect. This work provides new insight into quantum behavior and prompts further comparison of SME and Bayesian formalisms to understand the nature of quantum systems. Our results are applicable to a variety of fields, from stochastic thermodynamics to quantum control.

Event-Based Robust Control for Uncertain Nonlinear Systems Using Adaptive Dynamic Programming.

PubMed

Zhang, Qichao; Zhao, Dongbin; Wang, Ding

2018-01-01

In this paper, the robust control problem for a class of continuous-time nonlinear system with unmatched uncertainties is investigated using an event-based control method. First, the robust control problem is transformed into a corresponding optimal control problem with an augmented control and an appropriate cost function. Under the event-based mechanism, we prove that the solution of the optimal control problem can asymptotically stabilize the uncertain system with an adaptive triggering condition. That is, the designed event-based controller is robust to the original uncertain system. Note that the event-based controller is updated only when the triggering condition is satisfied, which can save the communication resources between the plant and the controller. Then, a single network adaptive dynamic programming structure with experience replay technique is constructed to approach the optimal control policies. The stability of the closed-loop system with the event-based control policy and the augmented control policy is analyzed using the Lyapunov approach. Furthermore, we prove that the minimal intersample time is bounded by a nonzero positive constant, which excludes Zeno behavior during the learning process. Finally, two simulation examples are provided to demonstrate the effectiveness of the proposed control scheme.

Discrete Space-Time: History and Recent Developments

NASA Astrophysics Data System (ADS)

Crouse, David

2017-01-01

Discussed in this work is the long history and debate of whether space and time are discrete or continuous. Starting from Zeno of Elea and progressing to Heisenberg and others, the issues with discrete space are discussed, including: Lorentz contraction (time dilation) of the ostensibly smallest spatial (temporal) interval, maintaining isotropy, violations of causality, and conservation of energy and momentum. It is shown that there are solutions to all these issues, such that discrete space is a viable model, yet the solution require strict non-absolute space (i.e., Mach's principle) and a re-analysis of the concept of measurement and the foundations of special relativity. In developing these solutions, the long forgotten but important debate between Albert Einstein and Henri Bergson concerning time will be discussed. Also discussed is the resolution to the Weyl tile argument against discrete space; however, the solution involves a modified version of the typical distance formula. One example effect of discrete space is then discussed, namely how it necessarily imposes order upon Wheeler's quantum foam, changing the foam into a gravity crystal and yielding crystalline properties of bandgaps, Brilluoin zones and negative inertial mass for astronomical bodies.

The role of pattern recognition in creative problem solving: a case study in search of new mathematics for biology.

PubMed

Hong, Felix T

2013-09-01

Rosen classified sciences into two categories: formalizable and unformalizable. Whereas formalizable sciences expressed in terms of mathematical theories were highly valued by Rutherford, Hutchins pointed out that unformalizable parts of soft sciences are of genuine interest and importance. Attempts to build mathematical theories for biology in the past century was met with modest and sporadic successes, and only in simple systems. In this article, a qualitative model of humans' high creativity is presented as a starting point to consider whether the gap between soft and hard sciences is bridgeable. Simonton's chance-configuration theory, which mimics the process of evolution, was modified and improved. By treating problem solving as a process of pattern recognition, the known dichotomy of visual thinking vs. verbal thinking can be recast in terms of analog pattern recognition (non-algorithmic process) and digital pattern recognition (algorithmic process), respectively. Additional concepts commonly encountered in computer science, operations research and artificial intelligence were also invoked: heuristic searching, parallel and sequential processing. The refurbished chance-configuration model is now capable of explaining several long-standing puzzles in human cognition: a) why novel discoveries often came without prior warning, b) why some creators had no ideas about the source of inspiration even after the fact, c) why some creators were consistently luckier than others, and, last but not least, d) why it was so difficult to explain what intuition, inspiration, insight, hunch, serendipity, etc. are all about. The predictive power of the present model was tested by means of resolving Zeno's paradox of Achilles and the Tortoise after one deliberately invoked visual thinking. Additional evidence of its predictive power must await future large-scale field studies. The analysis was further generalized to constructions of scientific theories in general. This approach is in line with Campbell's evolutionary epistemology. Instead of treating science as immutable Natural Laws, which already existed and which were just waiting to be discovered, scientific theories are regarded as humans' mental constructs, which must be invented to reconcile with observed natural phenomena. In this way, the pursuit of science is shifted from diligent and systematic (or random) searching for existing Natural Laws to firing up humans' imagination to comprehend Nature's behavioral pattern. The insights gained in understanding human creativity indicated that new mathematics that is capable of handling effectively parallel processing and human subjectivity is sorely needed. The past classification of formalizability vs. non-formalizability was made in reference to contemporary mathematics. Rosen's conclusion did not preclude future inventions of new biology-friendly mathematics. Copyright © 2013 Elsevier Ltd. All rights reserved.

Event-based cluster synchronization of coupled genetic regulatory networks

NASA Astrophysics Data System (ADS)

Yue, Dandan; Guan, Zhi-Hong; Li, Tao; Liao, Rui-Quan; Liu, Feng; Lai, Qiang

2017-09-01

In this paper, the cluster synchronization of coupled genetic regulatory networks with a directed topology is studied by using the event-based strategy and pinning control. An event-triggered condition with a threshold consisting of the neighbors' discrete states at their own event time instants and a state-independent exponential decay function is proposed. The intra-cluster states information and extra-cluster states information are involved in the threshold in different ways. By using the Lyapunov function approach and the theories of matrices and inequalities, we establish the cluster synchronization criterion. It is shown that both the avoidance of continuous transmission of information and the exclusion of the Zeno behavior are ensured under the presented triggering condition. Explicit conditions on the parameters in the threshold are obtained for synchronization. The stability criterion of a single GRN is also given under the reduced triggering condition. Numerical examples are provided to validate the theoretical results.

Fast generations of tree-type three-dimensional entanglement via Lewis-Riesenfeld invariants and transitionless quantum driving

PubMed Central

Wu, Jin-Lei; Ji, Xin; Zhang, Shou

2016-01-01

Recently, a novel three-dimensional entangled state called tree-type entanglement, which is likely to have applications for improving quantum communication security, was prepared via adiabatic passage by Song et al. Here we propose two schemes for fast generating tree-type three-dimensional entanglement among three spatially separated atoms via shortcuts to adiabatic passage. With the help of quantum Zeno dynamics, two kinds of different but equivalent methods, Lewis-Riesenfeld invariants and transitionless quantum driving, are applied to construct shortcuts to adiabatic passage. The comparisons between the two methods are discussed. The strict numerical simulations show that the tree-type three-dimensional entangled states can be fast prepared with quite high fidelities and the two schemes are both robust against the variations in the parameters, atomic spontaneous emissions and the cavity-fiber photon leakages. PMID:27667583

Quantum Mechanics for Everybody: An autonomous MOOC on EdX for nonscientists

NASA Astrophysics Data System (ADS)

Freericks, James; Cutler, Dylan; Vieira-Barbosa, Lucas

2017-01-01

We have launched a MOOC for nonscientists that teaches quantum mechanics using the Feynman methodology as outlined in his QED book and in a similar book by Daniel Styer. Using a combination of videos, voice-over powerpoint animations, computer simulations and interactive tutorials, we teach the fundamentals of quantum mechanics employing a minimum of math (high school algebra, square roots, and a little trigonometry) but going into detail on a number of complex quantum ideas. We begin with the Stern-Gerlach experiment, including delayed choice and Bell's inequality variants. Then we focus on light developing the quantum theory for partial reflection and diffraction. At this point we demonstrate the complexity of quantum physics by showing how watched and unwatched two-slit experiments behave differently and how quantum particles interfere. The four week course ends with advanced topics in light where we cover the idea of an interaction free measurement, the quantum Zeno effect and indistinguishable particles via the Hong-Ou-Mandel experiment. We hope this MOOC will reach thousands of students interesting in learning quantum mechanics without any dumbing down or the need to learn complex math. It can also be used with undergraduates to help with conceptual understanding. Funded by the National Science Foundation under grants numbered PHY-1620555 and PHY-1314295 and by Georgetown University.

Stable Isotopes, Quantum Computing and Consciousness

NASA Astrophysics Data System (ADS)

Berezin, Alexander A.

2000-10-01

Recent proposals of quantum computing/computers (QC) based on nuclear spins suggest that consciousness (CON) activity may be related (assisted) to subset of C13 atoms incorporated randomly, or quasirandomly, in neural structures. Consider two DNA chains. Even if they are completely identical chemically (same sequence of codons), patterns of 12C and 13C isotopes in them are different (possible origin of personal individuality). Perhaps it is subsystem of nuclear spins of 13C "sublattice" which forms dynamical system capable of QC and on which CON is "spanned". Some issues related to this hypothesis are: (1) existence of CON-driven positional correlations among C13 atoms, (2) motion (hopping) of C13 via enhanced neutron tunneling, cf. quantum "anti Zeno-effect", (3) possible optimization of concentration of QC-active C13 atoms above their standard isotopic abundance, (4) characteristic time-scales for operation of C13-based QC (perrhaps, broad range of scales), (5) reflection of QC dynamics of C13 on CON, (6) possibility that C13-based QC operates "above" level of "regular" CON (perhaps, Jungian sub/super-CON), (7) isotopicity as connector to universal Library of Patterns ("Platonic World"), (8) self-stabilization of coherence in C13 (sub)system. Some of this questions are, in principle, experimentally addressable through shifting of isotopic abundances.

Hydrodynamic Modeling and Its Application in AUC.

PubMed

Rocco, Mattia; Byron, Olwyn

2015-01-01

The hydrodynamic parameters measured in an AUC experiment, s(20,w) and D(t)(20,w)(0), can be used to gain information on the solution structure of (bio)macromolecules and their assemblies. This entails comparing the measured parameters with those that can be computed from usually "dry" structures by "hydrodynamic modeling." In this chapter, we will first briefly put hydrodynamic modeling in perspective and present the basic physics behind it as implemented in the most commonly used methods. The important "hydration" issue is also touched upon, and the distinction between rigid bodies versus those for which flexibility must be considered in the modeling process is then made. The available hydrodynamic modeling/computation programs, HYDROPRO, BEST, SoMo, AtoB, and Zeno, the latter four all implemented within the US-SOMO suite, are described and their performance evaluated. Finally, some literature examples are presented to illustrate the potential applications of hydrodynamics in the expanding field of multiresolution modeling. © 2015 Elsevier Inc. All rights reserved.

An event-triggered control approach for the leader-tracking problem with heterogeneous agents

NASA Astrophysics Data System (ADS)

Garcia, Eloy; Cao, Yongcan; Casbeer, David W.

2018-05-01

This paper presents an event-triggered control and communication framework for the cooperative leader-tracking problem with communication constraints. Continuous communication among agents is not assumed in this work and decentralised event-based strategies are proposed for agents with heterogeneous linear dynamics. Also, the leader dynamics are unknown and only intermittent measurements of its states are obtained by a subset of the followers. The event-based method not only represents a way to restrict communication among agents, but it also provides a decentralised scheme for scheduling information broadcasts. Notably, each agent is able to determine its own broadcasting instants independently of any other agent in the network. In an extension, the case where transmission of information is affected by time-varying communication delays is addressed. Finally, positive lower-bounds on the inter-event time intervals are obtained in order to show that Zeno behaviour does not exist and, therefore, continuous exchange of information is never needed in this framework.

Simulations of RF capture with barrier bucket in booster at injection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardner, C.J.

2012-01-23

As part of the effort to increase the number of ions per bunch in RHIC, a new scheme for RF capture of EBIS ions in Booster at injection has been developed. The scheme was proposed by M. Blaskiewicz and J.M. Brennan. It employs a barrier bucket to hold a half turn of beam in place during capture into two adjacent harmonic 4 buckets. After acceleration, this allows for 8 transfers of 2 bunches from Booster into 16 buckets on the AGS injection porch. During the Fall of 2011 the necessary hardware was developed and implemented by the RF and Controlsmore » groups. The scheme is presently being commissioned by K.L. Zeno with Au32+ ions from EBIS. In this note we carry out simulations of the RF capture. These are meant to serve as benchmarks for what can be achieved in practice. They also allow for an estimate of the longitudinal emittance of the bunches on the AGS injection porch.« less

Twenty-Five Centuries of Quantum Physics: From Pythagoras to Us, and from Subjectivism to Realism

NASA Astrophysics Data System (ADS)

Bunge, Mario

Three main theses are proposed. The first is that the idea of a quantum or minimal unit is not peculiar to quantum theory, since it already occurs in the classical theories of elasticity and electrolysis. Second, the peculiarities of the objects described by quantum theory are the following: their basic laws are probabilistic; some of their properties, such as position and energy, are blunt rather than sharp; two particles that were once together continue to be associated even after becoming spatially separated; and the vacuum has physical properties, so that it is a kind of matter. Third, the orthodox or Copenhagen interpretation of the theory is false, and may conveniently be replaced with a realist (though not classicist) interpretation. Heisenberg's inequality, Schrödinger's cat and Zeno's quantum paradox are discussed in the light of the two rival interpretations. It is also shown that the experiments that falsified Bell's inequality do not refute realism but the classicism inherent in hidden variables theories.

t-topology on the n-dimensional Minkowski space

NASA Astrophysics Data System (ADS)

Agrawal, Gunjan; Shrivastava, Sampada

2009-05-01

In this paper, a topological study of the n-dimensional Minkowski space, n >1, with t-topology, denoted by Mt, has been carried out. This topology, unlike the usual Euclidean one, is more physically appealing being defined by means of the Lorentzian metric. It shares many topological properties with similar candidate topologies and it has the advantage of being first countable. Compact sets of Mt and continuous maps into Mt are studied using the notion of Zeno sequences besides characterizing those sets that have the same subspace topologies induced from the Euclidean and t-topologies on n-dimensional Minkowski space. A necessary and sufficient condition for a compact set in the Euclidean n-space to be compact in Mt is obtained, thereby proving that the n-cube, n >1, as a subspace of Mt, is not compact, while a segment on a timelike line is compact in Mt. This study leads to the nonsimply connectedness of Mt, for n =2. Further, Minkowski space with s-topology has also been dealt with.

Signatures of a quantum dynamical phase transition in a three-spin system in presence of a spin environment

NASA Astrophysics Data System (ADS)

Álvarez, Gonzalo A.; Levstein, Patricia R.; Pastawski, Horacio M.

2007-09-01

We have observed an environmentally induced quantum dynamical phase transition in the dynamics of a two-spin experimental swapping gate [G.A. Álvarez, E.P. Danieli, P.R. Levstein, H.M. Pastawski, J. Chem. Phys. 124 (2006) 194507]. There, the exchange of the coupled states |↑,↓> and |↓,↑> gives an oscillation with a Rabi frequency b/ℏ (the spin-spin coupling). The interaction, ℏ/τSE with a spin-bath degrades the oscillation with a characteristic decoherence time. We showed that the swapping regime is restricted only to bτSE≳ℏ. However, beyond a critical interaction with the environment the swapping freezes and the system enters to a Quantum Zeno dynamical phase where relaxation decreases as coupling with the environment increases. Here, we solve the quantum dynamics of a two-spin system coupled to a spin-bath within a Liouville-von Neumann quantum master equation and we compare the results with our previous work within the Keldysh formalism. Then, we extend the model to a three interacting spin system where only one is coupled to the environment. Beyond a critical interaction the two spins not coupled to the environment oscillate with the bare Rabi frequency and relax more slowly. This effect is more pronounced when the anisotropy of the system-environment (SE) interaction goes from a purely XY to an Ising interaction form.

The effect of various primers on shear bond strength of zirconia ceramic and resin composite.

PubMed

Sanohkan, Sasiwimol; Kukiattrakoon, Boonlert; Larpboonphol, Narongrit; Sae-Yib, Taewalit; Jampa, Thibet; Manoppan, Satawat

2013-11-01

To determine the in vitro shear bond strengths (SBS) of zirconia ceramic to resin composite after various primer treatments. Forty zirconia ceramic (Zeno, Wieland Dental) specimens (10 mm in diameter and 2 mm thick) were prepared, sandblasted with 50 μm alumina, and divided into four groups (n = 10). Three experimental groups were surface treated with three primers; CP (RelyX Ceramic Primer, 3M ESPE), AP (Alloy Primer, Kuraray Medical), and MP (Monobond Plus, Ivoclar Vivadent AG). One group was not treated and served as the control. All specimens were bonded to a resin composite (Filtek Supreme XT, 3M ESPE) cylinder with an adhesive system (Adper Scotchbond Multi-Purpose Plus Adhesive, 3M ESPE) and then stored in 100% humidity at 37°C for 24 h before SBS testing in a universal testing machine. Mean SBS (MPa) were analyzed with one-way analysis of variance (ANOVA) and the Tukey's Honestly Significant Difference (HSD) test (α = 0.05). Group AP yielded the highest mean and standard deviation (SD) value of SBS (16.8 ± 2.5 MPa) and Group C presented the lowest mean and SD value (15.4 ± 1.6 MPa). The SBS did not differ significantly among the groups (P = 0.079). Within the limitations of this study, the SBS values between zirconia ceramic to resin composite using various primers and untreated surface were not significantly different.

Quantum fluctuation theorems and power measurements

NASA Astrophysics Data System (ADS)

Prasanna Venkatesh, B.; Watanabe, Gentaro; Talkner, Peter

2015-07-01

Work in the paradigm of the quantum fluctuation theorems of Crooks and Jarzynski is determined by projective measurements of energy at the beginning and end of the force protocol. In analogy to classical systems, we consider an alternative definition of work given by the integral of the supplied power determined by integrating up the results of repeated measurements of the instantaneous power during the force protocol. We observe that such a definition of work, in spite of taking account of the process dependence, has different possible values and statistics from the work determined by the conventional two energy measurement approach (TEMA). In the limit of many projective measurements of power, the system’s dynamics is frozen in the power measurement basis due to the quantum Zeno effect leading to statistics only trivially dependent on the force protocol. In general the Jarzynski relation is not satisfied except for the case when the instantaneous power operator commutes with the total Hamiltonian at all times. We also consider properties of the joint statistics of power-based definition of work and TEMA work in protocols where both values are determined. This allows us to quantify their correlations. Relaxing the projective measurement condition, weak continuous measurements of power are considered within the stochastic master equation formalism. Even in this scenario the power-based work statistics is in general not able to reproduce qualitative features of the TEMA work statistics.

Quantum Kinetics and the Zeno Ansatz: Sterile Neutrino Dark Matter in the Early Universe

NASA Astrophysics Data System (ADS)

Dvornikov, Olexiy V.

We solved the quantum kinetic equations for the evolution of neutrino states in the early universe. Starting at high temperatures, we evolve neutrino states to observe the resonant conversion of active-to-sterile neutrinos in a lepton asymmetric (more neutrinos than anti-neutrinos) universe. We find that at high temperatures, the high neutrino scattering and oscillation rates enforce a local equilibrium that balances the growth of coherence at the oscillation rate and the damping of coherence through scattering. This equilibrium, which we call a "quantum kinetic equilibrium," appears to approximately hold throughout the neutrino evolution, from the initial conditions through resonances that may be non adiabatic. Using this quantum kinetic equilibrium informs a proper choice of the initial conditions of the neutrino state and the relaxation process that occurs to this equilibrium when the initial conditions (as are typically chosen in the literature) are not coincident with the equilibrium values. We also discuss how to use this equilibrium to reduce the computational expense of solving the full quantum kinetic equations for neutrino states evolving in the early universe.

Stoicism, the physician, and care of medical outliers

PubMed Central

Papadimos, Thomas J

2004-01-01

Background Medical outliers present a medical, psychological, social, and economic challenge to the physicians who care for them. The determinism of Stoic thought is explored as an intellectual basis for the pursuit of a correct mental attitude that will provide aid and comfort to physicians who care for medical outliers, thus fostering continued physician engagement in their care. Discussion The Stoic topics of good, the preferable, the morally indifferent, living consistently, and appropriate actions are reviewed. Furthermore, Zeno's cardinal virtues of Justice, Temperance, Bravery, and Wisdom are addressed, as are the Stoic passions of fear, lust, mental pain, and mental pleasure. These concepts must be understood by physicians if they are to comprehend and accept the Stoic view as it relates to having the proper attitude when caring for those with long-term and/or costly illnesses. Summary Practicing physicians, especially those that are hospital based, and most assuredly those practicing critical care medicine, will be emotionally challenged by the medical outlier. A Stoic approach to such a social and psychological burden may be of benefit. PMID:15588293

Improving the Critic Learning for Event-Based Nonlinear $H_{\\infty }$ Control Design.

PubMed

Wang, Ding; He, Haibo; Liu, Derong

2017-10-01

In this paper, we aim at improving the critic learning criterion to cope with the event-based nonlinear H ∞ state feedback control design. First of all, the H ∞ control problem is regarded as a two-player zero-sum game and the adaptive critic mechanism is used to achieve the minimax optimization under event-based environment. Then, based on an improved updating rule, the event-based optimal control law and the time-based worst-case disturbance law are obtained approximately by training a single critic neural network. The initial stabilizing control is no longer required during the implementation process of the new algorithm. Next, the closed-loop system is formulated as an impulsive model and its stability issue is handled by incorporating the improved learning criterion. The infamous Zeno behavior of the present event-based design is also avoided through theoretical analysis on the lower bound of the minimal intersample time. Finally, the applications to an aircraft dynamics and a robot arm plant are carried out to verify the efficient performance of the present novel design method.

Characteristic dynamics near two coalescing eigenvalues incorporating continuum threshold effects

NASA Astrophysics Data System (ADS)

Garmon, Savannah; Ordonez, Gonzalo

2017-06-01

It has been reported in the literature that the survival probability P(t) near an exceptional point where two eigenstates coalesce should generally exhibit an evolution P (t ) ˜t2e-Γ t, in which Γ is the decay rate of the coalesced eigenstate; this has been verified in a microwave billiard experiment [B. Dietz et al., Phys. Rev. E 75, 027201 (2007)]. However, the heuristic effective Hamiltonian that is usually employed to obtain this result ignores the possible influence of the continuum threshold on the dynamics. By contrast, in this work we employ an analytical approach starting from the microscopic Hamiltonian representing two simple models in order to show that the continuum threshold has a strong influence on the dynamics near exceptional points in a variety of circumstances. To report our results, we divide the exceptional points in Hermitian open quantum systems into two cases: at an EP2A two virtual bound states coalesce before forming a resonance, anti-resonance pair with complex conjugate eigenvalues, while at an EP2B two resonances coalesce before forming two different resonances. For the EP2B, which is the case studied in the microwave billiard experiment, we verify that the survival probability exhibits the previously reported modified exponential decay on intermediate time scales, but this is replaced with an inverse power law on very long time scales. Meanwhile, for the EP2A the influence from the continuum threshold is so strong that the evolution is non-exponential on all time scales and the heuristic approach fails completely. When the EP2A appears very near the threshold, we obtain the novel evolution P (t ) ˜1 -C1√{t } on intermediate time scales, while further away the parabolic decay (Zeno dynamics) on short time scales is enhanced.

Effect of in vitro aging on the flexural strength and probability to fracture of Y-TZP zirconia ceramics for all-ceramic restorations.

PubMed

Siarampi, Eleni; Kontonasaki, Eleana; Andrikopoulos, Konstantinos S; Kantiranis, Nikolaos; Voyiatzis, George A; Zorba, Triantafillia; Paraskevopoulos, Konstantinos M; Koidis, Petros

2014-12-01

Dental zirconia restorations should present long-term clinical survival and be in service within the oral environment for many years. However, low temperature degradation could affect their mechanical properties and survival. The aim of this study was to investigate the effect of in vitro aging on the flexural strength of yttrium-stabilized (Y-TZP) zirconia ceramics for ceramic restorations. One hundred twenty bar-shaped specimens were prepared from two ceramics (ZENO Zr (WI) and IPS e.max(®) ZirCAD (IV)), and loaded until fracture according to ISO 6872. The specimens from each ceramic (nx=60) were divided in three groups (control, aged for 5h, aged for 10h). One-way ANOVA was used to assess statistically significant differences among flexural strength values (P<0.05). The variability of the flexural strength values was analyzed using the two-parameter Weibull distribution function, which was applied for the estimation of Weibull modulus (m) and characteristic strength (σ0). The crystalline phase polymorphs of the materials (tetragonal, t, and monoclinic, m, zirconia) were investigated by X-ray diffraction (XRD) analysis, Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy. A slight increase of the flexural strength after 5h, and a decrease after 10h of aging, was recorded for both ceramics, however statistically significant was for the WI group (P<0.05). Both ceramics presented a t→m phase transformation, with the m-phase increasing from 4 to 5% at 5h to around 15% after 10h. The significant reduction of the flexural strength after 10h of in vitro aging, suggests high fracture probability for one of the zirconia ceramics tested. Copyright © 2014 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

[Preliminary evaluation of clinical effect of computer aided design and computer aided manufacture zirconia crown].

PubMed

Wang, Yu-guang; Xing, Yan-xi; Sun, Yu-chun; Zhao, Yi-jiao; Lü, Pei-jun; Wang, Yong

2013-06-01

To evaluate clinical effects of computer aided design and computer aided manufacturing (CAD/CAM) milled zirconia crown in three aspects: aesthetic, contact wear and fracture. Sixty patients were divided into two groups.In one group, 35 full contour CAD/CAM zirconia crown were made on molars of 30 patients. The manufacturing process of zirconia crown was as follow. First, the three dimensional(3-D) data of working models, antagonist impression and check records were acquired by 3-D laser scanning Dental wings S50. Then full contour zirconia crowns, which had functional occlusal contacts with antagonistic teeth, and appropriate contact with adjacent teeth were designed with Zeno-CAD(V4.2.5.5.12919) software. ZENOSTAR Zr pure zirconia material was milled in digital controlled machine WIELAND 4030 M1.In the end, the zirconia crown were completed with the method of second sintering and polishing. After clinical try-in, the crown was cemented.In the control group, thirty gold alloy full crown were made and cemented on molars of 30 patients. According to the modified U S Public Health Service Criteria(USPHS) evaluation standard, all crowns were evaluated on the same day, at three months, half a year, one year and two years following delivery. There were three aspects we were focusing on in the evaluation: aesthetic, contact wear(restoration and antagonist), and fracture. In all the prosthesis we evaluated during the 24 months, no fracture was found. Contact wear of crowns varies according to different antagonist teeth. The zirconia crowns show privilege in aesthesis, toughness and anti-wearing.However, there is contact wear on antagonistic natural teeth. Thus it is a good choice when full zirconia crowns are indicated on two antagonistic teeth in both jaws.

Cathodal Transcranial Direct Current Stimulation (tDCS) to the Right Cerebellar Hemisphere Affects Motor Adaptation During Gait.

PubMed

Fernandez, Lara; Albein-Urios, Natalia; Kirkovski, Melissa; McGinley, Jennifer L; Murphy, Anna T; Hyde, Christian; Stokes, Mark A; Rinehart, Nicole J; Enticott, Peter G

2017-02-01

The cerebellum appears to play a key role in the development of internal rules that allow fast, predictive adjustments to novel stimuli. This is crucial for adaptive motor processes, such as those involved in walking, where cerebellar dysfunction has been found to increase variability in gait parameters. Motor adaptation is a process that results in a progressive reduction in errors as movements are adjusted to meet demands, and within the cerebellum, this seems to be localised primarily within the right hemisphere. To examine the role of the right cerebellar hemisphere in adaptive gait, cathodal transcranial direct current stimulation (tDCS) was administered to the right cerebellar hemisphere of 14 healthy adults in a randomised, double-blind, crossover study. Adaptation to a series of distinct spatial and temporal templates was assessed across tDCS condition via a pressure-sensitive gait mat (ProtoKinetics Zeno walkway), on which participants walked with an induced 'limp' at a non-preferred pace. Variability was assessed across key spatial-temporal gait parameters. It was hypothesised that cathodal tDCS to the right cerebellar hemisphere would disrupt adaptation to the templates, reflected in a failure to reduce variability following stimulation. In partial support, adaptation was disrupted following tDCS on one of the four spatial-temporal templates used. However, there was no evidence for general effects on either the spatial or temporal domain. This suggests, under specific conditions, a coupling of spatial and temporal processing in the right cerebellar hemisphere and highlights the potential importance of task complexity in cerebellar function.

Supersymmetrical bounding of asymmetric states and quantum phase transitions by anti-crossing of symmetric states

PubMed Central

Afzal, Muhammad Imran; Lee, Yong Tak

2016-01-01

Von Neumann and Wigner theorized the bounding and anti-crossing of eigenstates. Experiments have demonstrated that owing to anti-crossing and similar radiation rates, the graphene-like resonance of inhomogeneously strained photonic eigenstates can generate a pseudomagnetic field, bandgaps and Landau levels, whereas exponential or dissimilar rates induce non-Hermicity. Here, we experimentally demonstrate higher-order supersymmetry and quantum phase transitions by resonance between similar one-dimensional lattices. The lattices consisted of inhomogeneous strain-like phases of triangular solitons. The resonance created two-dimensional, inhomogeneously deformed photonic graphene. All parent eigenstates were annihilated. Eigenstates of mildly strained solitons were annihilated at similar rates through one tail and generated Hermitian bounded eigenstates. The strongly strained solitons with positive phase defects were annihilated at exponential rates through one tail, which bounded eigenstates through non-Hermitianally generated exceptional points. Supersymmetry was evident, with preservation of the shapes and relative phase differences of the parent solitons. Localizations of energies generated from annihilations of mildly and strongly strained soliton eigenstates were responsible for geometrical (Berry) and topological phase transitions, respectively. Both contributed to generating a quantum Zeno phase, whereas only strong twists generated topological (Anderson) localization. Anti-bunching-like condensation was also observed. PMID:27966596

Simulations of Merging Helion Bunches on the AGS Injection Porch

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardner, C. J.

During the setup of helions for the FY2014 RHIC run it was discovered that the standard scheme for merging bunches on the AGS injection porch required an injection kicker pulse shorter than what was available. To overcome this difficulty, K. Zeno proposed and developed an interesting and unusual alternative which uses RF harmonic numbers 12, 4, 2 (rather than the standard 8, 4, 2) to merge 8 helion bunches into 2. In this note we carry out simulations that illustrate how the alternative scheme works and how it compares with the standard scheme. This is done in Sections 13 andmore » 14. A scheme in which 6 bunches are merged into 1 is simulated in Section 15. This may be useful if more helions per merged bunch are needed in future runs. General formulae for the simulations are given in Sections 9 through 12. For completeness, Sections 1 through 8 give a derivation of the turn-by-turn equations of longitudinal motion at constant magnetic field. The derivation is based on the work of MacLachlan. The reader may wish to skip over these Sections and start with Section 9.« less

CYBERWAR-2012/13: Siegel 2011 Predicted Cyberwar Via ACHILLES-HEEL DIGITS BEQS BEC ZERO-DIGIT BEC of/in ACHILLES-HEEL DIGITS Log-Law Algebraic-Inversion to ONLY BEQS BEC Digit-Physics U Barabasi Network/Graph-Physics BEQS BEC JAMMING Denial-of-Access(DOA) Attacks 2012-Instantiations

NASA Astrophysics Data System (ADS)

Huffmann, Master; Siegel, Edward Carl-Ludwig

2013-03-01

Newcomb-Benford(NeWBe)-Siegel log-law BEC Digit-Physics Network/Graph-Physics Barabasi et.al. evolving-``complex''-networks/graphs BEC JAMMING DOA attacks: Amazon(weekends: Microsoft I.E.-7/8(vs. Firefox): Memorial-day, Labor-day,...), MANY U.S.-Banks:WF,BoA,UB,UBS,...instantiations AGAIN militate for MANDATORY CONVERSION to PARALLEL ANALOG FAULT-TOLERANT but slow(er) SECURITY-ASSURANCE networks/graphs in parallel with faster ``sexy'' DIGITAL-Networks/graphs:``Cloud'', telecomm: n-G,..., because of common ACHILLES-HEEL VULNERABILITY: DIGITS!!! ``In fast-hare versus slow-tortoise race, Slow-But-Steady ALWAYS WINS!!!'' (Zeno). {Euler [#s(1732)] ∑- ∏()-Riemann[Monats. Akad. Berlin (1859)] ∑- ∏()- Kummer-Bernoulli (#s)}-Newcomb [Am.J.Math.4(1),39 (81) discovery of the QUANTUM!!!]-{Planck (01)]}-{Einstein (05)]-Poincar e [Calcul Probabilités,313(12)]-Weyl[Goett. Nach.(14); Math.Ann.77,313(16)]-(Bose (24)-Einstein(25)]-VS. -Fermi (27)-Dirac(27))-Menger [Dimensiontheorie(29)]-Benford [J.Am. Phil.Soc.78,115(38)]-Kac[Maths Stats.-Reason. (55)]- Raimi [Sci.Am.221,109(69)]-Jech-Hill [Proc.AMS,123,3,887(95)] log-function

Evaluation of the grand-canonical partition function using expanded Wang-Landau simulations. V. Impact of an electric field on the thermodynamic properties and ideality contours of water

NASA Astrophysics Data System (ADS)

Desgranges, Caroline; Delhommelle, Jerome

2016-11-01

Using molecular simulation, we assess the impact of an electric field on the properties of water, modeled with the SPC/E potential, over a wide range of states and conditions. Electric fields of the order of 0.1 V/Å and beyond are found to have a significant impact on the grand-canonical partition function of water, resulting in shifts in the chemical potential at the vapor-liquid coexistence of up to 20%. This, in turn, leads to an increase in the critical temperatures by close to 7% for a field of 0.2 V/Å, to lower vapor pressures, and to much larger entropies of vaporization (by up to 35%). We interpret these results in terms of the greater density change at the transition and of the increased structural order resulting from the applied field. The thermodynamics of compressed liquids and of supercritical water are also analyzed over a wide range of pressures, leading to the determination of the Zeno line and of the curve of ideal enthalpy that span the supercritical region of the phase diagram. Rescaling the phase diagrams obtained for the different field strengths by their respective critical properties allows us to draw a correspondence between these systems for fields of up to 0.2 V/Å.

Science Requirements for a Space Flight Experiment Entitled Critical Viscosity of Xenon

NASA Technical Reports Server (NTRS)

Berg, Robert F.; Moldover, Michael R.

1993-01-01

We propose to measure in low gravity the viscosity of xenon close to its critical point. The accuracy will be sufficient to eliminate uncertainties currently associated with the analysis of l-g experiments. The measurements will provide the first direct observation of the predicted power-law divergence of viscosity in a pure fluid. The measurements will also strengthen Zeno's test of mode coupling theory by greatly increasing the reliability of the extrapolation of viscosity to low reduced temperatures. Our scientific objectives are described in more detail in one of the attached reports. The low-gravity experiment will be the final stage of a program whose completed ground-based stages are: (1) theoretical studies by one of the principal investigators (MRM) and coworkers, (2) critical viscosity measurements of binary liquid mixtures, (3) critical viscosity measurements of pure fluids in l-g, and development of a suitable vibration-insensitive viscometer. Our technical approach is described in the draft Science Requirements Document. One of us (MRM) has reviewed opportunities for critical phenomena research in low gravity. Both of us were co-principal investigators in the Thermal Equilibration Experiment in the Critical Point Facility, flown on IML-1 in 1992. From this experience, and from the technical maturity of our ground-based work, we believe our critical point viscometer is ready for development as a flight experiment.

Fundamental limits to frequency estimation: a comprehensive microscopic perspective

NASA Astrophysics Data System (ADS)

Haase, J. F.; Smirne, A.; Kołodyński, J.; Demkowicz-Dobrzański, R.; Huelga, S. F.

2018-05-01

We consider a metrology scenario in which qubit-like probes are used to sense an external field that affects their energy splitting in a linear fashion. Following the frequency estimation approach in which one optimizes the state and sensing time of the probes to maximize the sensitivity, we provide a systematic study of the attainable precision under the impact of noise originating from independent bosonic baths. Specifically, we invoke an explicit microscopic derivation of the probe dynamics using the spin-boson model with weak coupling of arbitrary geometry. We clarify how the secular approximation leads to a phase-covariant (PC) dynamics, where the noise terms commute with the field Hamiltonian, while the inclusion of non-secular contributions breaks the PC. Moreover, unless one restricts to a particular (i.e., Ohmic) spectral density of the bath modes, the noise terms may contain relevant information about the frequency to be estimated. Thus, by considering general evolutions of a single probe, we study regimes in which these two effects have a non-negligible impact on the achievable precision. We then consider baths of Ohmic spectral density yet fully accounting for the lack of PC, in order to characterize the ultimate attainable scaling of precision when N probes are used in parallel. Crucially, we show that beyond the semigroup (Lindbladian) regime the Zeno limit imposing the 1/N 3/2 scaling of the mean squared error, recently derived assuming PC, generalises to any dynamics of the probes, unless the latter are coupled to the baths in the direction perfectly transversal to the frequency encoding—when a novel scaling of 1/N 7/4 arises. As our microscopic approach covers all classes of dissipative dynamics, from semigroup to non-Markovian ones (each of them potentially non-phase-covariant), it provides an exhaustive picture, in which all the different asymptotic scalings of precision naturally emerge.

Does Multi-morbidity Mediate the Effect of Socioeconomics on Self-rated Health? Cross-country Differences

PubMed Central

Assari, Shervin; Lankarani, Maryam Moghani

2015-01-01

Background: This study explored cross-country differences in how multi-morbidity explains the effects of socioeconomic characteristics on self-rated health. Methods: The study borrowed data from the Research on Early Life and Aging Trends and Effects. Participants were 44,530 individuals (age > 65 years) who were sampled from 15 countries (i.e. United States, China, India, Russia, Costa Rica, Puerto Rico, Mexico, Argentina, Barbados, Brazil, Chile, Cuba, Uruguay, Ghana and South Africa). Multi-morbidity was measured as number of chronic medical conditions. In Model I, main effects of socioeconomic factors on self-rated health were calculated using country-specific logistic regressions. In Model II, number of chronic conditions were also added to the models to find changes in coefficients for demographic and socioeconomic factors. Results: In the United States, number of chronic medical conditions explained the effect of income on subjective health. In Puerto Rico, number of chronic medical conditions explained the effect of marital status on subjective health. In Costa Rica, Argentina, Barbados, Cuba, and Uruguay, number of chronic medical conditions explained gender disparities in subjective health. In China, Mexico, Brazil, Russia, Chile, India, Ghana and South Africa, number of chronic medical conditions did not explain the effect of demographic or socioeconomic factors on subjective health. Conclusions: Multi-morbidity explains the effect of demographic and socioeconomic factors on subjective health in some but not other countries. Further research is needed. PMID:26445632

ESCOLEX: a grade-level lexical database from European Portuguese elementary to middle school textbooks.

PubMed

Soares, Ana Paula; Medeiros, José Carlos; Simões, Alberto; Machado, João; Costa, Ana; Iriarte, Álvaro; de Almeida, José João; Pinheiro, Ana P; Comesaña, Montserrat

2014-03-01

In this article, we introduce ESCOLEX, the first European Portuguese children's lexical database with grade-level-adjusted word frequency statistics. Computed from a 3.2-million-word corpus, ESCOLEX provides 48,381 word forms extracted from 171 elementary and middle school textbooks for 6- to 11-year-old children attending the first six grades in the Portuguese educational system. Like other children's grade-level databases (e.g., Carroll, Davies, & Richman, 1971; Corral, Ferrero, & Goikoetxea, Behavior Research Methods, 41, 1009-1017, 2009; Lété, Sprenger-Charolles, & Colé, Behavior Research Methods, Instruments, & Computers, 36, 156-166, 2004; Zeno, Ivens, Millard, Duvvuri, 1995), ESCOLEX provides four frequency indices for each grade: overall word frequency (F), index of dispersion across the selected textbooks (D), estimated frequency per million words (U), and standard frequency index (SFI). It also provides a new measure, contextual diversity (CD). In addition, the number of letters in the word and its part(s) of speech, number of syllables, syllable structure, and adult frequencies taken from P-PAL (a European Portuguese corpus-based lexical database; Soares, Comesaña, Iriarte, Almeida, Simões, Costa, …, Machado, 2010; Soares, Iriarte, Almeida, Simões, Costa, França, …, Comesaña, in press) are provided. ESCOLEX will be a useful tool both for researchers interested in language processing and development and for professionals in need of verbal materials adjusted to children's developmental stages. ESCOLEX can be downloaded along with this article or from http://p-pal.di.uminho.pt/about/databases .

Knowledge Growth of Mathematics Teachers during Professional Activity Based on the Task of Lesson Explaining

ERIC Educational Resources Information Center

Peng, Aihui

2007-01-01

"Lesson explaining" has been developed in China from an evaluative resource to an effective form of teacher professional development with the value of emphasizing teacher reflective practice. This paper begins with a general description of lesson explaining. Then an example of "explaining" a mathematics lesson for teaching…

Coherent control of diamond defects for quantum information science and quantum sensing

NASA Astrophysics Data System (ADS)

Maurer, Peter

Quantum mechanics, arguably one of the greatest achievements of modern physics, has not only fundamentally changed our understanding of nature but is also taking an ever increasing role in engineering. Today, the control of quantum systems has already had a far-reaching impact on time and frequency metrology. By gaining further control over a large variety of different quantum systems, many potential applications are emerging. Those applications range from the development of quantum sensors and new quantum metrological approaches to the realization of quantum information processors and quantum networks. Unfortunately most quantum systems are very fragile objects that require tremendous experimental effort to avoid dephasing. Being able to control the interaction between a quantum system with its local environment embodies therefore an important aspect for application and hence is at the focus of this thesis. Nitrogen Vacancy (NV) color centers in diamond have recently attracted attention as a room temperature solid state spin system that expresses long coherence times. The electronic spin associated with NV centers can be efficiently manipulated, initialized and readout using microwave and optical techniques. Inspired by these extraordinary properties, much effort has been dedicated to use NV centers as a building block for scalable room temperature quantum information processing and quantum communication as well as a quantum sensing. In the first part of this thesis we demonstrate that by decoupling the spin from the local environment the coherence time of a NV quantum register can be extended by three order of magnitudes. Employing a novel dissipative mechanism in combination with dynamical decoupling, memory times exceeding one second are observed. The second part shows that, based on quantum control, NV centers in nano-diamonds provide a nanoscale temperature sensor with unprecedented accuracy enabling local temperature measurements in living biological cells. This opens the door for the engineering of nano-scaled chemical reactions to the study of temperature dependent biological processes. Finally, a novel technique is introduced that facilitates optical spin detection with nanoscale resolution based on an optical far-field technique; by combining this with a 'quantum Zeno' like effect coherent manipulation of nominally identical spins at a nanoscale is achieved.

Enhanced Optical and Electric Manipulation of a Quantum Gas of KRb Molecules

NASA Astrophysics Data System (ADS)

Covey, Jacob P.

Polar molecules are an ideal platform for studying quantum information and quantum simulation due to their long-range dipolar interactions. However, they have many degrees of freedom at disparate energy scales and thus are difficult to cool. Ultracold KRb molecules near quantum degeneracy were first produced in 2008. Nevertheless, it was found that even when prepared in the absolute lowest state chemical reactions can make the gas unstable. During my PhD we worked to mitigate these limitations by loading molecules into an optical lattice where the tunneling rates, and thus the chemistry, can be exquisitely controlled. This setting allowed us to start using the rotational degree of freedom as a pseudo-spin, and paved the way for studying models of quantum magnetism, such as the t-J model and the XXZ model. Further, by allowing molecules of two "spin''-states to tunnel in the lattice, we were able to observe a continuous manifestion of the quantum Zeno effect, where increased mobility counterintuitively suppresses dissipation from inelastic collisions. In a deep lattice we observed dipolar spin-exchange interactions, and we were able to elucidate their truly many-body nature. These two sets of experiments informed us that the filling fraction of the molecules in the lattice was only 5-10%, and so we implemented a quantum synthesis approach where atomic insulators were used to maximize the number of sites with one K and one Rb, and then these "doublons'' were converted to molecules with a filling of 30%. Despite these successes, a number of tools such as high resolution detection and addressing as well as large, stable electric fields were unavailable. Also during my PhD I led efforts to design, build, test, and implement a new apparatus which provides access to these tools and more. We have successfully produced ultracold molecules in this new apparatus, and we are now applying AC and DC electric fields with in vacuum electrodes. This apparatus will allow us to study quantum magnetism in a large electric field, and to detect the dynamics of out-of-equilibrium many-body states.

The Effect of Religion on Ethnic Tolerance in Malaysia: The Application of Rational Choice Theory (RCT) and the Theory of Planned Behaviour (TPB)

ERIC Educational Resources Information Center

Idris, Fazilah; Abdullah, Mohd Richard Neles; Ahmad, Abdul Razak; Mansor, Ahmad Zamri

2016-01-01

There has been little research done on explaining the ethnic tolerance behavior from the perspective of sociological theories. The authors chose rational choice theory and the theory of planned behavior as they are widely used in explaining the human social behaviour. In this article, the theories are used to explain the effects of religion on…

The Perceptual Basis of the Modality Effect in Multimedia Learning

ERIC Educational Resources Information Center

Rummer, Ralf; Schweppe, Judith; Furstenberg, Anne; Scheiter, Katharina; Zindler, Antje

2011-01-01

Various studies have demonstrated an advantage of auditory over visual text modality when learning with texts and pictures. To explain this modality effect, two complementary assumptions are proposed by cognitive theories of multimedia learning: first, the visuospatial load hypothesis, which explains the modality effect in terms of visuospatial…

Explaining mastitis incidence in Dutch dairy farming: the influence of farmers' attitudes and behaviour.

PubMed

Jansen, J; van den Borne, B H P; Renes, R J; van Schaik, G; Lam, T J G M; Leeuwis, C

2009-11-15

When mastitis incidence increases, either infection pressure has increased or cows' resistance has decreased. This usually indicates that farm management is not optimal. Numerous quantitative studies have demonstrated the effect of management practices on mastitis. In most of these studies, the identified risk factors could explain only part of the variance in mastitis incidence on farms. Several studies suggest that the unexplained variance is caused by farmers' attitudes towards different aspects of mastitis treatment and preventive behaviour. This study aims to determine, to quantify and to specify the extent to which farmers' attitudes, over and above farmers' behaviour, are factors that explain the variation in mastitis incidence, measured in terms of the quantifiable effect of management factors. An extensive survey on self-reported attitudes, behaviour and mastitis incidence was conducted on 336 Dutch dairy farms. Results of multiple linear regression analyses show that farmers' self-reported behaviour and attitudes together explain 48%, 31% and 23% of the variation within, respectively, the average farm bulk milk somatic cell count (BMSCC), the clinical mastitis incidence and the combined clinical and subclinical mastitis incidence. Both behaviour and attitudes explain part of the variance. However, most of the variance in all three dependant measures is explained solely by the attitude variables. The variation in BMSCC value is best explained by (1) farmers' normative frame of reference about mastitis, (2) farmers' perceptions about the control of mastitis and (3) the perceived effect of a BMSCC penalty level. The variation in clinical mastitis is best explained by farmers' perceptions about mastitis control. The variation in the combined clinical and subclinical mastitis incidence rate is best explained by the perceived effect of a BMSCC penalty level and the frequency of contact with others. The results of this study show that farmers' attitudes are a better measure than farmers' self-reported behaviour to explain and predict differences in mastitis incidence between farms. Consequently, future research and animal health promotion programs should take into account not only farmers' behaviour, but also farmers' attitudes. This study provides a first empirical investigation into the social processes applicable to mastitis incidence and is therefore considered a good starting point for future research to further investigate the causal effect of attitude change on farmers' behaviour and animal health.

A Practitioner's Handbook for Institutional Effectiveness and Student Outcomes Assessment Implementation. Third Edition.

ERIC Educational Resources Information Center

Nichols, James O.

This guide is intended for college and university administrators responsible for designing and implementing a model for assessment of student outcomes and institutional effectiveness. The first chapter explains use of the handbook and introduces the institutional effectiveness paradigm on which it is based. The second chapter explains the model…

Pitfalls in Evaluating the Effectiveness of Case Management Programs for Homeless Persons: Lessons from the NIAAA Community Demonstration Program.

ERIC Educational Resources Information Center

Orwin, Robert G.; And Others

1994-01-01

Evaluation findings of the National Institute on Alcohol Abuse and Alcoholism (NIAAA) Community Demonstration Program show few clear indications of the effectiveness of case management approaches. This article identifies phenomena that explain the lack of positive effects and suggests that evaluation problems may explain apparent negative…

From Ancient Paradoxes to Modern Orbit Determination

NASA Astrophysics Data System (ADS)

Giorgini, Jon D.

2008-09-01

In the 5th century BC, Zeno advanced a set of paradoxes to show motion and time are impossible, hence an illusion. The problem of motion has since driven much scientific thought and discovery, extending to Einstein's insights and the quantum revolution. To determine and predict the motion of remote objects within the solar system, a methodology has been refined over centuries. It integrates ideas from astronomy, physics, mathematics, measurement, and probability theory, having motivated most of those developments. Recently generalized and made numerically efficient, statistical orbit determination has made it possible to remotely fly Magellan and other spacecraft through the turbulent atmospheres of Venus and other planets while estimating atmospheric structure and internal mass distributions of the planet. Over limited time-scales, the methodology can predict the position of the Moon within a meter and asteroids within tens of meters -- their velocities at the millimeter per second level -- while characterizing the probable correctness of the prediction. Current software and networks disseminate such ephemeris information in moments; over the last 12 years, 10 million ephemerides have been provided by the Horizons system, at the request of 300000 different users. Applications range from ground and space telescope pointing to correlation with observations recorded on Babylonian cuneiform tablets. Rapid orbit updates are particularly important for planetary radars integrating weak small-body echoes moving quickly through the frequency spectrum due to relative motion. A loop is established in which the predicted delay-Doppler measurement and uncertainties are used to configure the radar. Both predictions are then compared to actual results, the asteroid or comet orbit solution improved, and the radar system optimally adjusted. Still, after 2500 years and tremendous descriptive success, there remain substantial problems understanding and predicting motion.

Sources of motivation, interpersonal conflict management styles, and leadership effectiveness: a structural model.

PubMed

Barbuto, John E; Xu, Ye

2006-02-01

126 leaders and 624 employees were sampled to test the relationship between sources of motivation and conflict management styles of leaders and how these variables influence effectiveness of leadership. Five sources of motivation measured by the Motivation Sources Inventory were tested-intrinsic process, instrumental, self-concept external, self-concept internal, and goal internalization. These sources of work motivation were associated with Rahim's modes of interpersonal conflict management-dominating, avoiding, obliging, complying, and integrating-and to perceived leadership effectiveness. A structural equation model tested leaders' conflict management styles and leadership effectiveness based upon different sources of work motivation. The model explained variance for obliging (65%), dominating (79%), avoiding (76%), and compromising (68%), but explained little variance for integrating (7%). The model explained only 28% of the variance in leader effectiveness.

Interactions between Defining, Explaining and Classifying: The Case of Increasing and Decreasing Sequences

ERIC Educational Resources Information Center

Alcock, Lara; Simpson, Adrian

2017-01-01

This paper describes a study in which we investigated relationships between defining mathematical concepts--increasing and decreasing infinite sequences--explaining their meanings and classifying consistently with formal definitions. We explored the effect of defining, explaining or studying a definition on subsequent classification, and the…

Promoting Conceptual Change in First Year Students' Understanding of Evaporation

ERIC Educational Resources Information Center

Costu, Bayram; Ayas, Alipasa; Niaz, Mansoor

2010-01-01

We constructed the PDEODE (Predict-Discuss-Explain-Observe-Discuss-Explain) teaching strategy, a variant of the classical POE (Predict-Observe-Explain) activity, to promote conceptual change, and investigated its effectiveness on student understanding of the evaporation concept. The sample consisted of 52 first year students in a primary science…

The Effect of Self-Explaining on Robust Learning

ERIC Educational Resources Information Center

Hausmann, Robert G. M.; VanLehn, Kurt

2010-01-01

Self-explaining is a domain-independent learning strategy that generally leads to a robust understanding of the domain material. However, there are two potential explanations for its effectiveness. First, self-explanation generates additional "content" that does not exist in the instructional materials. Second, when compared to…

Energy Conservation: Implementing an Effective Campus Program.

ERIC Educational Resources Information Center

Marsee, Jeff

After reviewing the physical plant environment and temperature control equipment at Eastfield College (Texas), this paper explains how redirected efforts toward energy conservation can result in important cost/usage savings. Electricity billing rates are explained to provide a stronger usage strategy for cost effectiveness. Two methods of reducing…

Using Expectancy Effects Theory To Analyze the Groups Who Supported Senator McCarthy.

ERIC Educational Resources Information Center

Corder, Lloyd E.

In this essay, Festinger's cognitive dissonance theory (which seeks to explain how individuals try to reconcile holding two inconsistent beliefs at the same time) is used to explore the nature of expectancy effects and what possible roles they play in the thinking of the radical right. The paper first defines expectancy effects and explains how…

Disentangling environmental and spatial effects on phylogenetic structure of angiosperm tree communities in China.

PubMed

Qian, Hong; Chen, Shengbin; Zhang, Jin-Long

2017-07-17

Niche-based and neutrality-based theories are two major classes of theories explaining the assembly mechanisms of local communities. Both theories have been frequently used to explain species diversity and composition in local communities but their relative importance remains unclear. Here, we analyzed 57 assemblages of angiosperm trees in 0.1-ha forest plots across China to examine the effects of environmental heterogeneity (relevant to niche-based processes) and spatial contingency (relevant to neutrality-based processes) on phylogenetic structure of angiosperm tree assemblages distributed across a wide range of environment and space. Phylogenetic structure was quantified with six phylogenetic metrics (i.e., phylogenetic diversity, mean pairwise distance, mean nearest taxon distance, and the standardized effect sizes of these three metrics), which emphasize on different depths of evolutionary histories and account for different degrees of species richness effects. Our results showed that the variation in phylogenetic metrics explained independently by environmental variables was on average much greater than that explained independently by spatial structure, and the vast majority of the variation in phylogenetic metrics was explained by spatially structured environmental variables. We conclude that niche-based processes have played a more important role than neutrality-based processes in driving phylogenetic structure of angiosperm tree species in forest communities in China.

Overview of urban climate

Treesearch

Roscoe R., Jr. Braham

1977-01-01

The broad features of urban climate anomalies are described and explained by combining recent METROMEX data with those from prior studies. The urban heat island is well understood, and urban effects upon cloud nuclei and cloud microstructure are clearly observed and explained in part; but the causes of urban effects upon rainfall remain speculative.

Electroconvulsive Therapy: A Primer for Mental Health Counselors.

ERIC Educational Resources Information Center

Leinbaugh, Tracy C.

2001-01-01

Electroconvulsive therapy is the treatment of choice for severe depressive episodes. Although little definitive research exists to explain its effectiveness, since its development in 1938 it has proven effective for the treatment of depression with psychotic features and suicidal ideation. Explains the procedure and discusses implications for the…

Extent of height variability explained by known height-associated genetic variants in an isolated population of the Adriatic coast of Croatia.

PubMed

Zhang, Ge; Karns, Rebekah; Sun, Guangyun; Indugula, Subba Rao; Cheng, Hong; Havas-Augustin, Dubravka; Novokmet, Natalija; Rudan, Dusko; Durakovic, Zijad; Missoni, Sasa; Chakraborty, Ranajit; Rudan, Pavao; Deka, Ranjan

2011-01-01

Human height is a classical example of a polygenic quantitative trait. Recent large-scale genome-wide association studies (GWAS) have identified more than 200 height-associated loci, though these variants explain only 2∼10% of overall variability of normal height. The objective of this study was to investigate the variance explained by these loci in a relatively isolated population of European descent with limited admixture and homogeneous genetic background from the Adriatic coast of Croatia. In a sample of 1304 individuals from the island population of Hvar, Croatia, we performed genome-wide SNP typing and assessed the variance explained by genetic scores constructed from different panels of height-associated SNPs extracted from five published studies. The combined information of the 180 SNPs reported by Lango Allen el al. explained 7.94% of phenotypic variation in our sample. Genetic scores based on 20~50 SNPs reported by the remaining individual GWA studies explained 3~5% of height variance. These percentages of variance explained were within ranges comparable to the original studies and heterogeneity tests did not detect significant differences in effect size estimates between our study and the original reports, if the estimates were obtained from populations of European descent. We have evaluated the portability of height-associated loci and the overall fitting of estimated effect sizes reported in large cohorts to an isolated population. We found proportions of explained height variability were comparable to multiple reference GWAS in cohorts of European descent. These results indicate similar genetic architecture and comparable effect sizes of height loci among populations of European descent. © 2011 Zhang et al.

Self-Explaining Effect in General Chemistry Instruction: Eliciting Overt Categorical Behaviours by Design

ERIC Educational Resources Information Center

Villalta-Cerdas, Adrian; Sandi-Urena, Santiago

2014-01-01

Self-explaining refers to the generation of inferences about causal connections between objects and events. In science, this may be summarised as making sense of how and why actual or hypothetical phenomena take place. Research findings in educational psychology show that implementing activities that elicit self-explaining improves learning in…

An empirical model for ocean radar backscatter and its application in inversion routine to eliminate wind speed and direction effects

NASA Technical Reports Server (NTRS)

Dome, G. J.; Fung, A. K.; Moore, R. K.

1977-01-01

Several regression models were tested to explain the wind direction dependence of the 1975 JONSWAP (Joint North Sea Wave Project) scatterometer data. The models consider the radar backscatter as a harmonic function of wind direction. The constant term accounts for the major effect of wind speed and the sinusoidal terms for the effects of direction. The fundamental accounts for the difference in upwind and downwind returns, while the second harmonic explains the upwind-crosswind difference. It is shown that a second harmonic model appears to adequately explain the angular variation. A simple inversion technique, which uses two orthogonal scattering measurements, is also described which eliminates the effect of wind speed and direction. Vertical polarization was shown to be more effective in determining both wind speed and direction than horizontal polarization.

Enhancing Effective Administration at Faculty Level through Shared Leadership

ERIC Educational Resources Information Center

Afful, Deborah

2015-01-01

We live in the world of knowledge, and knowledge keeps increasing in shape and complexity. As a result, no single individual has the repository of knowledge required to effectively manage an organisation all alone to affect organisational performance positively. This explains why administration is explained as doing things through the efforts of…

Explaining the Effectiveness of the Contrast Culture Method for Managing Interpersonal Interactions across Cultures

ERIC Educational Resources Information Center

Hiratsuka, Hiroyoshi; Suzuki, Hanako; Pusina, Alexis

2016-01-01

One of the current challenges in the field of intercultural education comes from the limited availability of training efficacy studies. The present study focused on explaining the effectiveness of the Contrast Culture Method (CCM) as an intercultural education method for managing interpersonal interactions across cultures between graduate…

Explaining University Students' Effective Use of E-Learning Platforms

ERIC Educational Resources Information Center

Moreno, Valter; Cavazotte, Flavia; Alves, Isabela

2017-01-01

Students' success in e-learning programs depends on how they adopt and embed technology into their learning activities. Drawing on the Technology Acceptance Model, we propose a framework to explain students' intention to use e-learning platforms effectively, that is, their intention to fully exploit system's functionalities in leaning processes,…

Explaining Differences between Retrospective and Traditional Pretest Self-Assessments: Competing Theories and Empirical Evidence

ERIC Educational Resources Information Center

Nimon, Kim

2014-01-01

Summarizing theory and results of empirical research, this article serves to illustrate why effects measured with retrospective pretests may be subject to bias and may not always be explained by response shift theory. It presents three contending theories to explain the difference between retrospective and traditional pretest results and considers…

How Was the Weekend? How the Social Context Underlies Weekend Effects in Happiness and Other Emotions for US Workers.

PubMed

Helliwell, John F; Wang, Shun

2015-01-01

In this paper we estimate the size of weekend effects for seven emotions and then explore their main determinants for the working population in the United States, using the Gallup/Healthways US Daily Poll 2008-2012. We first find that weekend effects exist for all emotions, and that these effects are not explained by sample selection bias. Full-time workers have larger weekend effects than do part-time workers. We then explore the sources of weekend effects and find that workplace trust and workplace social relations, combined with differences in social time spent with family and friends, together almost fully explain the weekend effects for happiness, laughter, enjoyment and sadness, for both full-time and part-time workers, with significant but smaller proportions explained for the remaining three emotions-worry, anger and stress. Finally, we show that workplace trust and social relations significantly improve emotions and life evaluations on both weekends and weekdays for all workers.

Chemistry of carcinogenic metals.

PubMed Central

Martell, A E

1981-01-01

The periodic distribution of known and suspected carcinogenic metal ions is described, and the chemical behavior of various types of metal ions is explained in terms of the general theory of hard and soft acids and bases. The chelate effect is elucidated, and the relatively high stability of metal chelates in very dilute solutions is discussed. The concepts employed for the chelate effect are extended to explain the high stabilities of macrocyclic and cryptate complexes. Procedures for the use of equilibrium data to determine the speciation of metal ions and complexes under varying solution conditions are described. Methods for assessing the interferences by hydrogen ion, competing metal ions, hydrolysis, and precipitation are explained, and are applied to systems containing iron(III) chelates of fourteen chelating agents designed for effective binding of the ferric ion. The donor groups available for the building up of multidentate ligands are presented, and the ways in which they may be combined to achieve high affinity and selectivity for certain types of metal ions are explained. PMID:6791915

Quantifying the Relative Contribution of Factors to Household Vehicle Miles of Travel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Garikapati, Venu; Singh, Abhilash C.; Astroza, Sebastian

Household vehicle miles of travel (VMT) has been exhibiting a steady growth in post-recession years in the United States and has reached record levels in 2017. With transportation accounting for 27 percent of greenhouse gas emissions, planning professionals are increasingly seeking ways to curb vehicular travel to advance sustainable, vibrant, and healthy communities. Although there is considerable understanding of the various factors that influence household vehicular travel, there is little knowledge of their relative contribution to explaining variance in household VMT. This paper presents a holistic analysis to identify the relative contribution of socio-economic and demographic characteristics, built environment attributes,more » residential self-selection effects, and social and spatial dependency effects in explaining household VMT production. The modeling framework employs a simultaneous equations model of residential location (density) choice and household VMT generation. The analysis is performed using household travel survey data from the New York metropolitan region. Model results showed insignificant spatial dependency effects, with socio-demographic variables explaining 33 percent, density (as a key measure of built environment attributes) explaining 12 percent, and self-selection effects explaining 11 percent of the total variance in the logarithm of household VMT. The remaining 44 percent remains unexplained and attributable to omitted variables and unobserved idiosyncratic factors, calling for further research in this domain to better understand the relative contribution of various drivers of household VMT.« less

Aetiology of teenage childbearing: reasons for familial effects.

PubMed

Olausson, P O; Lichtenstein, P; Cnattingius, S

2000-03-01

The aims of the present study were to evaluate the contribution of the genetic and environmental factors to the risk of teenage childbearing, and to study whether life style, socio-economic conditions, and personality traits could explain possible familial effects. We linked two population-based registers: the Swedish Twin Register and the Swedish Medical Birth Register. The study covers female twin pairs born between 1953 and 1958, having their first infant before the age of 30 years (n = 1885). In order to separate familial effects from other environmental influences, and genetic effects from shared environmental effects, only complete twin pairs with known zygosity were included, in all 260 monozygotic and 370 dizygotic twin pairs. We used quantitative genetic analyses to evaluate the importance of genetic and environmental effects for liability to teenage childbearing. Logistic regression analyses were used to estimate the effects of life style, socio-economic situation, and personality on the probability of teenage childbearing, and to study whether psychosocial factors could explain possible familial effects. Fifty-nine percent (0-76%) of the variance in being a teenage mother was attributable to heritable factors; 0% (0-49%) was due to shared environmental factors; and 41% (23-67%) was explained by non-shared environmental factors. Thus, the data were consistent with the hypothesis that the familial aggregation of teenage childbearing is completely explained by genetic factors, although the alternative hypothesis that familial aggregation is entirely explained by shared environmental factors cannot be ruled out. Significant effects of smoking habits, housing conditions, and educational level were found in relation to liability to teenage childbearing. However, the familial effects on risk of teenage childbearing were not mediated through similarities in life style and socio-economic factors. When studying risk factors for teenage childbearing, it is recommended to include life style and socio-economic variables as well as information about family history of teenage childbearing. Twin Research (2000) 3, 23-27.

The Effects of Poverty on Children's Socioemotional Development: An Ecological Systems Analysis.

ERIC Educational Resources Information Center

Eamon, Mary Keegan

2001-01-01

Bronfenbrenner's process-person-context-time model is used to examine theories that explain adverse effects of economic deprivation on children's socioemotional development. Processes of not only the family, but also those of the peer group and school, and in other levels of the ecological environment may also explain the relation between economic…

The Effectiveness of Predict-Observe-Explain Tasks in Diagnosing Students' Understanding of Science and in Identifying Their Levels of Achievement.

ERIC Educational Resources Information Center

Liew, Chong-Wah; Treagust, David F.

This study involves action research to explore the effectiveness of the Predict-Observe-Explain (POE) technique in diagnosing students' understanding of science and identifying their levels of achievement. A multidimensional interpretive framework is used to interpret students' understanding of science. The research methodology incorporated…

Investigating the Effectiveness of an Active Learning Based-Interactive Conceptual Instruction (ALBICI) on Electric Field Concept

ERIC Educational Resources Information Center

Samsudin, Achmad; Suhandi, Andi; Rusdiana, Dadi; Kaniawati, Ida; Costu, Bayram

2016-01-01

The aim of this study was to develop an Active Learning Based-Interactive Conceptual Instruction (ALBICI) model through PDEODE*E tasks (stands for Predict, Discuss, Explain, Observe, Discuss, Explore, and Explain) for promoting conceptual change and investigating its effectiveness of pre-service physics teachers' understanding on electric field…

Development and Assessment of Self-explaining Skills in College Chemistry Instruction

NASA Astrophysics Data System (ADS)

Villalta-Cerdas, Adrian

The prevalent trend in chemistry instruction relies on what has been described as the classroom game. In this model, students take a passive role and the instructor does all the explaining (thinking), and learning is trivialized to knowing the correct answers (memorizing) and being able to produce them when prompted (regurgitating). The generation of explanations is central to scientific and technological development. In the process of figuring out explanations, the generation of inferences relies on the application of skills associated with scientific behaviors (e.g., analytical reasoning and critical thinking). The process of explanation generation causes a deeper analysis and revision of the scientific models, thus impacting the conceptual understanding of such models. Although the process of generating authentic explanations is closer to the experience of doing science, this process is seldom replicated in science instruction. Self-explaining refers to the generation of inferences about causal connections between objects and events. In science, this may be summarized as making sense of how and why actual or hypothetical phenomena take place. Research findings in educational psychology show that implementing activities that elicit self-explaining improves learning in general and specifically enhances authentic learning in the sciences. Research also suggests that self-explaining influences many aspects of cognition, including acquisition of problem-solving skills and conceptual understanding. Although the evidence that links self-explaining and learning is substantial, most of the research has been conducted in experimental settings. The purpose of this work was to advance knowledge in this area by investigating the effect of different self-explaining tasks on self-explaining behavior and the effect of engaging in different levels of self-explaining on learning chemistry concepts. Unlike most of the research in the field, this work did not focus on advancing procedural knowledge through self-explanation of examples or conceptual understanding through self-explanation of textual information and concepts. Instead, it focused on an experience closer to doing science by presenting a familiar phenomenon to the participants and a fact that would potentially induce cognitive imbalance to then prompt them to self-explain. This work used a multi-condition, mixed-method approach to categorize students' self-explaining behaviors in response to learning tasks and link it to the performance in a post-learning task. Students were randomly assigned to conditions that included the following: studying an experts' explanation, explaining correct and incorrect answers, explaining agreement with another's answer, and explaining one's own answer for others to use. Data were gathered in the classroom ecology of a university, large-enrollment general chemistry course. Content and construct validity evidence support the functionality of the research instruments for the assessment of conceptual understanding of entropy and the Second Law of Thermodynamics. An in-depth analysis of the post-learning task showed that the data collected from the instrument is reliable, consistent and reproducible. Findings supported an association between the self-explaining tasks and students' self-explaining behaviors. Results showed distinct categorical self-explaining behaviors in students' written responses. These self-explaining behaviors were associated with the self-explaining task given to the students. Thoughtful design of learning tasks can effectively elicit engagement in sophisticated self-explaining in natural, large-enrollment college chemistry classroom environments. Comparison analyses of performance in the post-learning task suggested that in the context of large-enrollment college chemistry classroom environments, self-explaining activities improved students' conceptual understanding in chemistry. Overall, the work showed that students can self-explain chemical phenomena and apply the underlying chemistry concepts in the resolution of novel problems without direct intervention of an instructor. This work supports the incorporation of self-explaining activities in the repertoire of teaching practices of both experienced and novice instructors for general chemistry courses.

Operator-sum representation for bosonic Gaussian channels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ivan, J. Solomon; Sabapathy, Krishna Kumar; Simon, R.

2011-10-15

Operator-sum or Kraus representations for single-mode bosonic Gaussian channels are developed, and several of their consequences explored. The fact that the two-mode metaplectic operators acting as unitary purification of these channels do not, in their canonical form, mix the position and momentum variables is exploited to present a procedure which applies uniformly to all families in the Holevo classification. In this procedure the Kraus operators of every quantum-limited Gaussian channel can be simply read off from the matrix elements of a corresponding metaplectic operator. Kraus operators are employed to bring out, in the Fock basis, the manner in which themore » antilinear, unphysical matrix transposition map when accompanied by injection of a threshold classical noise becomes a physical channel, denoted D({kappa}) in the Holevo classification. The matrix transposition channels D({kappa}), D({kappa}{sup -1}) turn out to be a dual pair in the sense that their Kraus operators are related by the adjoint operation. The amplifier channel with amplification factor {kappa} and the beam-splitter channel with attenuation factor {kappa}{sup -1} turn out to be mutually dual in the same sense. The action of the quantum-limited attenuator and amplifier channels as simply scaling maps on suitable quasiprobabilities in phase space is examined in the Kraus picture. Consideration of cumulants is used to examine the issue of fixed points. The semigroup property of the amplifier and attenuator families leads in both cases to a Zeno-like effect arising as a consequence of interrupted evolution. In the cases of entanglement-breaking channels a description in terms of rank 1 Kraus operators is shown to emerge quite simply. In contradistinction, it is shown that there is not even one finite rank operator in the entire linear span of Kraus operators of the quantum-limited amplifier or attenuator families, an assertion far stronger than the statement that these are not entanglement breaking channels. A characterization of extremality in terms of Kraus operators, originally due to Choi, is employed to show that all quantum-limited Gaussian channels are extremal. The fact that almost every noisy Gaussian channel can be realized as a product of a pair of quantum-limited channels is used to construct a discrete set of linearly independent Kraus operators for these noisy Gaussian channels, including the classical noise channel, and these Kraus operators have a particularly simple structure.« less

Skewed Exposure to Environmental Antigens Complements Hygiene Hypothesis in Explaining the Rise of Allergy.

PubMed

Allaerts, Wilfried; Chang, Tse Wen

2017-06-01

The Hygiene Hypothesis has been recognized as an important cornerstone to explain the sudden increase in the prevalence of asthma and allergic diseases in modernized culture. The recent epidemic of allergic diseases is in contrast with the gradual implementation of Homo sapiens sapiens to the present-day forms of civilization. This civilization forms a gradual process with cumulative effects on the human immune system, which co-developed with parasitic and commensal Helminths. The clinical manifestation of this epidemic, however, became only visible in the second half of the twentieth century. In order to explain these clinical effects in terms of the underlying IgE-mediated reactions to innocuous environmental antigens, the low biodiversity of antigens in the domestic environment plays a pivotal role. The skewing of antigen exposure as a cumulative effect of reducing biodiversity in the immediate human environment as well as in changing food habits, provides a sufficient and parsimonious explanation for the rise in allergic diseases in a highly developed and helminth-free modernized culture. Socio-economic tendencies that incline towards a further reduction of environmental biodiversity may provide serious concern for future health. This article explains that the "Hygiene Hypothesis", the "Old Friends Hypothesis", and the "Skewed Antigen Exposure Hypothesis" are required to more fully explain the rise of allergy in modern societies.

The Relationship between Organizational Justice Perceptions, Level of School and Administrator Trust, and Organizational Citizenship Behaviors of Secondary School Teachers in Turkey

ERIC Educational Resources Information Center

Polat, Soner

2007-01-01

The objective of this research is to display; (a) the effect of organizational justice in explaining school trust, administrator trust and organizational citizenship behavior, (b)the effect of school trust and administrator trust in explaining organizational citizenship behavior, based on perceptions related with the variables of organizational…

Gender and General Strain Theory: A Comparison of Strains, Mediating, and Moderating Effects Explaining Three Types of Delinquency

ERIC Educational Resources Information Center

Moon, Byongook; Morash, Merry

2017-01-01

The present study of 659 Korean adolescents tests General Strain Theory's (GST) utility in explaining gender differences in delinquency causation. It models the effects of key strains, negative emotions, and a composite measure of several conditioning factors separately for boys and girls and for delinquency. Consistent with the theory, males and…

Probable Cause: A Decision Making Framework.

DTIC Science & Technology

1984-08-01

Thus, a biochemist may see the causal link between smoking and lung cancer as due to chemical effects of tar, nicotine , and the like, on cell structure...long term and complex effects like poverty can have short term and simple causes. Determinants of Gros Strength Causal chains. While the causal...explained is a standing state. For example, what is the cause of " poverty ?" Since the effect to be explained in a standing state of large duration and

Direct vs. Microclimate-Driven Effects of Tree Species Diversity on Litter Decomposition in Young Subtropical Forest Stands.

PubMed

Seidelmann, Katrin N; Scherer-Lorenzen, Michael; Niklaus, Pascal A

2016-01-01

Effects of tree species diversity on decomposition can operate via a multitude of mechanism, including alterations of microclimate by the forest canopy. Studying such effects in natural settings is complicated by the fact that topography also affects microclimate and thus decomposition, so that effects of diversity are more difficult to isolate. Here, we quantified decomposition rates of standard litter in young subtropical forest stands, separating effects of canopy tree species richness and topography, and quantifying their direct and micro-climate-mediated components. Our litterbag study was carried out at two experimental sites of a biodiversity-ecosystem functioning field experiment in south-east China (BEF-China). The field sites display strong topographical heterogeneity and were planted with tree communities ranging from monocultures to mixtures of 24 native subtropical tree species. Litter bags filled with senescent leaves of three native tree species were placed from Nov. 2011 to Oct. 2012 on 134 plots along the tree species diversity gradient. Topographic features were measured for all and microclimate in a subset of plots. Stand species richness, topography and microclimate explained important fractions of the variations in litter decomposition rates, with diversity and topographic effects in part mediated by microclimatic changes. Tree stands were 2-3 years old, but nevertheless tree species diversity explained more variation (54.3%) in decomposition than topography (7.7%). Tree species richness slowed litter decomposition, an effect that slightly depended on litter species identity. A large part of the variance in decomposition was explained by tree species composition, with the presence of three tree species playing a significant role. Microclimate explained 31.4% of the variance in decomposition, and was related to lower soil moisture. Within this microclimate effect, species diversity (without composition) explained 8.9% and topography 34.4% of variance. Topography mainly affected diurnal temperature amplitudes by varying incident solar radiation.

Direct vs. Microclimate-Driven Effects of Tree Species Diversity on Litter Decomposition in Young Subtropical Forest Stands

PubMed Central

Seidelmann, Katrin N.; Scherer-Lorenzen, Michael; Niklaus, Pascal A.

2016-01-01

Effects of tree species diversity on decomposition can operate via a multitude of mechanism, including alterations of microclimate by the forest canopy. Studying such effects in natural settings is complicated by the fact that topography also affects microclimate and thus decomposition, so that effects of diversity are more difficult to isolate. Here, we quantified decomposition rates of standard litter in young subtropical forest stands, separating effects of canopy tree species richness and topography, and quantifying their direct and micro-climate-mediated components. Our litterbag study was carried out at two experimental sites of a biodiversity-ecosystem functioning field experiment in south-east China (BEF-China). The field sites display strong topographical heterogeneity and were planted with tree communities ranging from monocultures to mixtures of 24 native subtropical tree species. Litter bags filled with senescent leaves of three native tree species were placed from Nov. 2011 to Oct. 2012 on 134 plots along the tree species diversity gradient. Topographic features were measured for all and microclimate in a subset of plots. Stand species richness, topography and microclimate explained important fractions of the variations in litter decomposition rates, with diversity and topographic effects in part mediated by microclimatic changes. Tree stands were 2–3 years old, but nevertheless tree species diversity explained more variation (54.3%) in decomposition than topography (7.7%). Tree species richness slowed litter decomposition, an effect that slightly depended on litter species identity. A large part of the variance in decomposition was explained by tree species composition, with the presence of three tree species playing a significant role. Microclimate explained 31.4% of the variance in decomposition, and was related to lower soil moisture. Within this microclimate effect, species diversity (without composition) explained 8.9% and topography 34.4% of variance. Topography mainly affected diurnal temperature amplitudes by varying incident solar radiation. PMID:27490180

A Geometric Interpretation of the Effective Uniaxial Anisotropy Field in Magnetic Films

NASA Astrophysics Data System (ADS)

Kozlov, V. I.

2018-01-01

It is shown that the effective uniaxial anisotropy field that is usually applied in thin magnetic films (TMFs), which is noncollinear to the magnetization vector, is insufficient for deeper understanding of these processes, although it explains many physical processes in films. The analysis of the magnetization discontinuity in films under certain conditions yields the component of the effective uniaxial anisotropy field collinear to the magnetization vector. This component explains the magnetization discontinuity and allows one to speak of the total effective uniaxial anisotropy field in TMFs.

Losing physics Pictionary

NASA Astrophysics Data System (ADS)

2017-06-01

Physics is often best explained with the help of a diagram, as anyone who has ever tried to explain the photoelectric effect will attest to. Drawing Physics by Don S Lemons looks back on how this has been the case throughout history.

N-Acetylcysteine as an antioxidant and disulphide breaking agent: the reasons why.

PubMed

Aldini, Giancarlo; Altomare, Alessandra; Baron, Giovanna; Vistoli, Giulio; Carini, Marina; Borsani, Luisa; Sergio, Francesco

2018-05-09

The main molecular mechanisms explaining the well-established antioxidant and reducing activity of N-acetylcysteine (NAC), the N-acetyl derivative of the natural amino acid l-cysteine, are summarised and critically reviewed. The antioxidant effect is due to the ability of NAC to act as a reduced glutathione (GSH) precursor; GSH is a well-known direct antioxidant and a substrate of several antioxidant enzymes. Moreover, in some conditions where a significant depletion of endogenous Cys and GSH occurs, NAC can act as a direct antioxidant for some oxidant species such as NO 2 and HOX. The antioxidant activity of NAC could also be due to its effect in breaking thiolated proteins, thus releasing free thiols as well as reduced proteins, which in some cases, such as for mercaptoalbumin, have important direct antioxidant activity. As well as being involved in the antioxidant mechanism, the disulphide breaking activity of NAC also explains its mucolytic activity which is due to its effect in reducing heavily cross-linked mucus glycoproteins. Chemical features explaining the efficient disulphide breaking activity of NAC are also explained.

Theoretical research on color indirect effects

NASA Astrophysics Data System (ADS)

Liu, T. C.; Liao, Changjun; Liu, Songhao

1995-05-01

Color indirect effects (CIE) means the physiological and psychological effects of color resulting from color vision. In this paper, we study CIE from the viewpoints of the integrated western and Chinese traditional medicine and the time quantum theory established by C. Y. Liu et al., respectively, and then put forward the color-automatic-nervous-subsystem model that could color excites parasympathetic subsystem and hot color excites sympathetic subsystem. Our theory is in agreement with modern color vision theory, and moreover, it leads to the resolution of the conflict between the color code theory and the time code theory oncolor vision. For the latitude phenomena on athlete stars number and the average lifespan, we also discuss the possibility of UV vision. The applications of our theory lead to our succeeding in explaining a number of physiological and psychological effects of color, in explaining the effects of age on color vision, and in explaining the Chinese chromophototherapy. We also discuss its application to neuroimmunology. This research provides the foundation of the clinical applications of chromophototherapy.

Spacing Repetitions Over Long Timescales: A Review and a Reconsolidation Explanation

PubMed Central

Smith, Christopher D.; Scarf, Damian

2017-01-01

Recent accounts of the spacing effect have proposed molecular explanations that explain spacing over short, but not long timescales. In the first half of this paper, we review research on the spacing effect that has employed spaces of 24 h or more across skill-related tasks, language-related tasks and generalization for adults and children. Throughout this review, we distinguish between learning and retention by defining learning (or acquisition) as performance at the end of training and retention as performance after a delay period. Using this distinction, we find age- and task-related differences in the manifestation of the spacing effect over long timescales. In the second half of this paper, we discuss a reconsolidation account of the spacing effect. In particular, we review the evidence that suggests the spacing of repetitions influences the subsequent consolidation and reconsolidation processes; we explain how a reconsolidation account may explain the findings for learning; the inverted-U curve for retention; and compare the reconsolidation account with previous consolidation accounts of the spacing effect. PMID:28676769

The Effectiveness of a Conceptually Focused Out-of-Class Intervention on Promoting Learning of Electricity by Township Learners

ERIC Educational Resources Information Center

Stott, Angela Elisabeth

2017-01-01

In this article I report a study into the effectiveness of a 6 week intervention aimed at promoting learning of electricity concepts by 91 Grade 8 and 9 township learners. Each week I taught these learners for an hour and they engaged with educational software for another hour. Analogy usage and predict-explain-observe-explain pedagogy were…

Students' mental models on the solubility and solubility product concept

NASA Astrophysics Data System (ADS)

Rahmi, Chusnur; Katmiati, Siti; Wiji, Mulyani, Sri

2017-05-01

This study aims to obtain some information regarding profile of students' mental models on the solubility and solubility product concept. A descriptive qualitative method was the method employed in the study. The participants of the study were students XI grade of a senior high school in Bandung. To collect the data, diagnostic test on mental model-prediction, observation, explanation (TDM-POE) instrument was employed in the study. The results of the study revealed that on the concept of precipitation formation of a reaction, 30% of students were not able to explain the precipitation formation of a reaction either in submicroscopic or symbolic level although the microscopic have been shown; 26% of students were able to explain the precipitation formation of a reaction based on the relation of Qsp and Ksp, but they were not able to explain the interaction of particles that involved in the reaction and to calculate Qsp; 26% of students were able to explain the precipitation formation of a reaction based on the relation of Qsp and Ksp, and determine the particles involved, but they did not have the knowledge about the interactions occured and were uncapable of calculating Qsp; and 18% of students were able to explain the precipitation formation of a reaction based on the relation of Qsp and Ksp, and determine the interactions of the particles involved in the reactions but they were not able to calculate Qsp. On the effect of adding common ions and decreasing pH towards the solubility concept, 96% of students were not able to explain the effect of adding common ions and decreasing pH towards the solubility either in submicroscopic or symbolic level although the microscopic have been shown; while 4% of students were only able to explain the effect of adding common ions towards the solubility based on the chemical equilibrium shifts and predict the effect of decreasing pH towards the solubility. However, they were not able to calculate the solubility before and after adding common ions and explain it up to the submicroscopic level either based on the shift of equilibrium solubility or the comparison of solubility calculation results before and after decreasing pH. Overall, the present study showed that most students obtain incomplete mental model on the solubility and solubility product concept. From the findings, it is recommended for the teachers to improve students' learning activity.

Chronic care management for patients with COPD: a critical review of available evidence.

PubMed

Lemmens, Karin M M; Lemmens, Lidwien C; Boom, José H C; Drewes, Hanneke W; Meeuwissen, Jolanda A C; Steuten, Lotte M G; Vrijhoef, Hubertus J M; Baan, Caroline A

2013-10-01

Clinical diversity and methodological heterogeneity exists between studies on chronic care management. This study aimed to examine the effectiveness of chronic care management in chronic obstructive pulmonary disease (COPD) while taking heterogeneity into account, enabling the understanding of and the decision making about such programmes. Three investigated sources of heterogeneity were study quality, length of follow-up, and number of intervention components. We performed a review of previously published reviews and meta-analyses on COPD chronic care management. Their primary studies that were analyzed as statistical, clinical and methodological heterogeneity were present. Meta-regression analyses were performed to explain the variances among the primary studies. Generally, the included reviews showed positive results on quality of life and hospitalizations. Inconclusive effects were found on emergency department visits and no effects on mortality. Pooled effects on hospitalizations, emergency department visits and quality of life of primary studies did not reach significant improvement. No effects were found on mortality. Meta-regression showed that the number of components of chronic care management programmes explained present heterogeneity for hospitalizations and emergency department visits. Four components showed significant effects on hospitalizations, whereas two components had significant effects on emergency department visits. Methodological study quality and length of follow-up did not significantly explain heterogeneity. This study demonstrated that COPD chronic care management has the potential to improve outcomes of care; heterogeneity in outcomes was explained. Further research is needed to elucidate the diversity between COPD chronic care management studies in terms of the effects measured and strengthen the support for chronic care management. © 2011 John Wiley & Sons Ltd.

The electron screening puzzle and nuclear clustering

DOE PAGES

Spitaleri, C.; Bertulani, C. A.; Fortunato, L.; ...

2016-02-12

Accurate measurements of nuclear reactions of astrophysical interest within, or close to, the Gamow peak show evidence of an unexpected effect attributed to the presence of atomic electrons in the target. The experiments need to include an effective "screening" potential to explain the enhancement of the cross sections at the lowest measurable energies. Despite various theoretical studies conducted over the past 20 years and numerous experimental measurements, a theory has not yet been found that can explain the cause of the exceedingly high values of the screening potential needed to explain the data. Furthermore, in this letter we show thatmore » instead of an atomic physics solution of the "electron screening puzzle", the reason for the large screening potential values is in fact due to clusterization effects in nuclear reactions, in particular for reaction involving light nuclei.« less

Can basin land use effects on physical characteristics of streams be determined at broad geographic scales?

USGS Publications Warehouse

Goldstein, R.M.; Carlisle, D.M.; Meador, M.R.; Short, T.M.

2007-01-01

The environmental setting (e.g., climate, topography, geology) and land use affect stream physical characteristics singly and cumulatively. At broad geographic scales, we determined the importance of environmental setting and land use in explaining variation in stream physical characteristics. We hypothesized that as the spatial scale decreased from national to regional, land use would explain more of the variation in stream physical characteristics because environmental settings become more homogeneous. At a national scale, stepwise linear regression indicated that environmental setting was more important in explaining variability in stream physical characteristics. Although statistically discernible, the amount of variation explained by land use was not remarkable due to low partial correlations. At level II ecoregion spatial scales (southeastern USA plains, central USA plains, and a combination of the western Cordillera and the western interior basins and ranges), environmental setting variables were again more important predictors of stream physical characteristics, however, as the spatial scale decreased from national to regional, the portion of variability in stream physical characteristics explained by basin land use increased. Development of stream habitat indicators of land use will depend upon an understanding of relations between stream physical characteristics and environmental factors at multiple spatial scales. Smaller spatial scales will be necessary to reduce the confounding effects of variable environmental settings before the effects of land use can be reliably assessed. ?? Springer Science+Business Media B.V. 2006.

A Theory of Age-Dependent Mutation and Senescence

PubMed Central

Moorad, Jacob A.; Promislow, Daniel E. L.

2008-01-01

Laboratory experiments show us that the deleterious character of accumulated novel age-specific mutations is reduced and made less variable with increased age. While theories of aging predict that the frequency of deleterious mutations at mutation–selection equilibrium will increase with the mutation's age of effect, they do not account for these age-related changes in the distribution of de novo mutational effects. Furthermore, no model predicts why this dependence of mutational effects upon age exists. Because the nature of mutational distributions plays a critical role in shaping patterns of senescence, we need to develop aging theory that explains and incorporates these effects. Here we propose a model that explains the age dependency of mutational effects by extending Fisher's geometrical model of adaptation to include a temporal dimension. Using a combination of simple analytical arguments and simulations, we show that our model predicts age-specific mutational distributions that are consistent with observations from mutation-accumulation experiments. Simulations show us that these age-specific mutational effects may generate patterns of senescence at mutation–selection equilibrium that are consistent with observed demographic patterns that are otherwise difficult to explain. PMID:18660535

Changes in the chloroplastic CO2 concentration explain much of the observed Kok effect: a model.

PubMed

Farquhar, Graham D; Busch, Florian A

2017-04-01

Mitochondrial respiration often appears to be inhibited in the light when compared with measurements in the dark. This inhibition is inferred from the response of the net CO 2 assimilation rate (A) to absorbed irradiance (I), changing slope around the light compensation point (I c ). We suggest a model that provides a plausible mechanistic explanation of this 'Kok effect'. The model uses the mathematical description of photosynthesis developed by Farquhar, von Caemmerer and Berry; it involves no inhibition of respiration rate in the light. We also describe a fitting technique for quantifying the Kok effect at low I. Changes in the chloroplastic CO 2 partial pressure (C c ) can explain curvature of A vs I, its diminution in C 4 plants and at low oxygen concentrations or high carbon dioxide concentrations in C 3 plants, and effects of dark respiration rate and of temperature. It also explains the apparent inhibition of respiration in the light as inferred by the Laisk approach. While there are probably other sources of curvature in A vs I, variation in C c can largely explain the curvature at low irradiance, and suggests that interpretation of day respiration compared with dark respiration of leaves on the basis of the Kok effect needs reassessment. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vanderveld, R. Ali; Flanagan, Eanna E.; Wasserman, Ira

Recently, there have been suggestions that the Type Ia supernova data can be explained using only general relativity and cold dark matter with no dark energy. In 'Swiss cheese' models of the Universe, the standard Friedmann-Robertson-Walker picture is modified by the introduction of mass-compensating spherical inhomogeneities, typically described by the Lemaitre-Tolman-Bondi metric. If these inhomogeneities correspond to underdense cores surrounded by mass-compensating overdense shells, then they can modify the luminosity distance-redshift relation in a way that can mimic accelerated expansion. It has been argued that this effect could be large enough to explain the supernova data without introducing dark energymore » or modified gravity. We show that the large apparent acceleration seen in some models can be explained in terms of standard weak field gravitational lensing together with insufficient randomization of void locations. The underdense regions focus the light less than the homogeneous background, thus dimming supernovae in a way that can mimic the effects of acceleration. With insufficient randomization of the spatial location of the voids and of the lines of sight, coherent defocusing can lead to anomalously large demagnification effects. We show that a proper randomization of the voids and lines of sight reduces the effect to the point that it can no longer explain the supernova data.« less

Mechanisms of the psychostimulant effects of caffeine: Implications for substance use disorders

PubMed Central

Ferré, Sergi

2016-01-01

Background The psychostimulant properties of caffeine are reviewed and compared with those of prototypical psychostimulants, able to cause substance use disorders (SUD). Caffeine produces psychomotor activating, reinforcing and arousing effects, which depend on its ability to disinhibit the brake that endogenous adenosine imposes on the ascending dopamine and arousal systems. Objectives A model that considers the striatal adenosine A2A-dopamine D2 receptor heteromer as a key modulator of dopamine-dependent striatal functions (reward-oriented behavior and learning of stimulus-reward and reward-response associations) is introduced, which should explain most of the psychomotor and reinforcing effects of caffeine. Highlights The model can explain the caffeine-induced rotational behavior in rats with unilateral striatal dopamine denervation and the ability of caffeine to reverse the adipsic-aphagic syndrome in dopamine-deficient rodents. The model can also explain the weaker reinforcing effects and low abuse liability of caffeine, compared with prototypical psychostimulants. Finally the model can explain the actual major societal dangers of caffeine: the ability of caffeine to potentiate the addictive and toxic effects of drugs of abuse, with the particularly alarming associations of caffeine (as adulterant) with cocaine, amphetamine derivatives and synthetic cathinones and energy drinks with alcohol; and the higher sensitivity of children and adolescents to the psychostimulants effects of caffeine and its possible increase in the vulnerability to develop SUD. Conclusions The striatal A2A-D2 receptor heteromer constitutes an unequivocal main pharmacological target of caffeine and provides the main mechanisms by which caffeine potentiates the acute and long-term effects of prototypical psychostimulants. PMID:26786412

Do changes in connectivity explain desertification?

USDA-ARS?s Scientific Manuscript database

Desertification, broad-scale land degradation in drylands, is a major environmental hazard facing inhabitants of the world’s deserts as well as an important component of global change. There is no unifying framework that simply and effectively explains different forms of desertification. Here we arg...

An Integrative Framework of Stress, Attention, and Visuomotor Performance

PubMed Central

Vine, Samuel J.; Moore, Lee J.; Wilson, Mark R.

2016-01-01

The aim of this article is to present an integrative conceptual framework that depicts the effect of acute stress on the performance of visually guided motor skills. We draw upon seminal theories highlighting the importance of subjective interpretations of stress on subsequent performance and outline how models of disrupted attentional control might explain this effect through impairments in visuomotor control. We first synthesize and critically discuss empirical support for theories examining these relationships in isolation. We then outline our integrative framework that seeks to provide a more complete picture of the interacting influences of stress responses (challenge and threat) and attention in explaining how elevated stress may lead to different visuomotor performance outcomes. We propose a number of mechanisms that explain why evaluations of stress are related to attentional control, and highlight the emotion of anxiety as the most likely candidate to explain why negative reactions to stress lead to disrupted attention and poor visuomotor skill performance. Finally, we propose a number of feedback loops that explain why stress responses are often self-perpetuating, as well as a number of proposed interventions that are designed to help improve or maintain performance in real world performance environments (e.g., sport, surgery, military, and aviation). PMID:27847484

Climate and Physiography Predict Mercury Concentrations in Game Fish Species in Quebec Lakes Better than Anthropogenic Disturbances.

PubMed

Lucotte, Marc; Paquet, Serge; Moingt, Matthieu

2016-05-01

The fluctuations of mercury levels (Hg) in fish consumed by sport fishers in North-Eastern America depend upon a plethora of interrelated biological and abiological factors. To identify the dominant factors ultimately controlling fish Hg concentrations, we compiled mercury levels (Hg) during the 1976-2010 period in 90 large natural lakes in Quebec (Canada) for two major game species: northern pike (Esox lucius) and walleye (Sander vitreus). Our statistical analysis included 28 geographic information system variables and 15 climatic variables, including sulfate deposition. Higher winter temperatures explained 36% of the variability in higher walleye growth rates, in turn accounting for 54% of the variability in lower Hg concentrations. For northern pike, the dominance of a flat topography in the watershed explained 31% of the variability in lower Hg concentrations. Higher mean annual temperatures explained 27% of the variability in higher pike Hg concentrations. Pelagic versus littoral preferred habitats for walleye and pike respectively could explain the contrasted effect of temperature between the two species. Heavy logging could only explain 2% of the increase in walleye Hg concentrations. The influence of mining on fish Hg concentrations appeared to be masked by climatic effects.

Functional traits explain ecosystem function through opposing mechanisms.

PubMed

Cadotte, Marc W

2017-08-01

The ability to explain why multispecies assemblages produce greater biomass compared to monocultures, has been a central goal in the quest to understand biodiversity effects on ecosystem function. Species contributions to ecosystem function can be driven by two processes: niche complementarity and a selection effect that is influenced by fitness (competitive) differences, and both can be approximated with measures of species' traits. It has been hypothesised that fitness differences are associated with few, singular traits while complementarity requires multidimensional trait measures. Here, using experimental data from plant assemblages, I show that the selection effect was strongest when trait dissimilarity was low, while complementarity was greatest with high trait dissimilarity. Selection effects were best explained by a single trait, plant height. Complementarity was correlated with dissimilarity across multiple traits, representing above and below ground processes. By identifying the relevant traits linked to ecosystem function, we obtain the ability to predict combinations of species that will maximise ecosystem function. © 2017 John Wiley & Sons Ltd/CNRS.

Effectiveness of Cooperative Learning Instructional Tools With Predict-Observe-Explain Strategy on the Topic of Cuboid and Cube Volume

NASA Astrophysics Data System (ADS)

Nurhuda; Lukito, A.; Masriyah

2018-01-01

This study aims to develop instructional tools and implement it to see the effectiveness. The method used in this research referred to Designing Effective Instruction. Experimental research with two-group pretest-posttest design method was conducted. The instructional tools have been developed is cooperative learning model with predict-observe-explain strategy on the topic of cuboid and cube volume which consist of lesson plans, POE tasks, and Tests. Instructional tools were of good quality by criteria of validity, practicality, and effectiveness. These instructional tools was very effective for teaching the volume of cuboid and cube. Cooperative instructional tool with predict-observe-explain (POE) strategy was good of quality because the teacher was easy to implement the steps of learning, students easy to understand the material and students’ learning outcomes completed classically. Learning by using this instructional tool was effective because learning activities were appropriate and students were very active. Students’ learning outcomes were completed classically and better than conventional learning. This study produced a good instructional tool and effectively used in learning. Therefore, these instructional tools can be used as an alternative to teach volume of cuboid and cube topics.

Long-term trends of bloater (Coregonus hoyi) recruitment in Lake Michigan: evidence for the effect of sex ratio

USGS Publications Warehouse

Bunnell, David B.; Madenjian, Charles P.; Croley, Thomas E.

2006-01-01

Long-term population trends are generally explained by factors extrinsic (e.g., climate, predation) rather than intrinsic (e.g., genetics, maternal effects) to the population. We sought to understand the long-term population dynamics of an important native Lake Michigan prey fish, the bloaterCoregonus hoyi. Over a 38-year time series, three 10- to 15-year phases occurred (poor, excellent, and then poor recruitment) without high interannual variability within a particular phase. We used dynamic linear models to determine whether extrinsic (winter and spring temperature, alewife predator densities) or intrinsic factors (population egg production, adult condition, adult sex ratio) explained variation in recruitment. Models that included population egg production, sex ratio, winter and spring temperature, and adult bloater condition explained the most variation. Of these variables, sex ratio, which ranged from 47% to 97% female across the time series, consistently had the greatest effect: recruitment declined with female predominance. Including biomass of adult alewife predators in the models did not explain additional variation. Overall our results indicated that bloater recruitment is linked to its sex ratio, but understanding the underlying mechanisms will require additional efforts.

Empirical Validation of the Information–Motivation–Behavioral Skills Model of Diabetes Medication Adherence: A Framework for Intervention

PubMed Central

Mayberry, Lindsay S.; Osborn, Chandra Y.

2014-01-01

OBJECTIVE Suboptimal adherence to diabetes medications is prevalent and associated with unfavorable health outcomes, but it remains unclear what intervention content is necessary to effectively promote medication adherence in diabetes. In other disease contexts, the Information–Motivation–Behavioral skills (IMB) model has effectively explained and promoted medication adherence and thus may have utility in explaining and promoting adherence to diabetes medications. We tested the IMB model’s hypotheses in a sample of adults with type 2 diabetes. RESEARCH DESIGN AND METHODS Participants (N = 314) completed an interviewer-administered survey and A1C test. Structural equation models tested the effects of diabetes medication adherence-related information, motivation, and behavioral skills on medication adherence and the effect of medication adherence on A1C. RESULTS The IMB elements explained 41% of the variance in adherence, and adherence explained 9% of the variance in A1C. As predicted, behavioral skills had a direct effect on adherence (β = 0.59; P < 0.001) and mediated the effects of information (indirect effect 0.08 [0.01–0.15]) and motivation (indirect effect 0.12 [0.05–0.20]) on adherence. Medication adherence significantly predicted glycemic control (β = −0.30; P < 0.001). Neither insulin status nor regimen complexity was associated with adherence, and neither moderated associations between the IMB constructs and adherence. CONCLUSIONS The results support the IMB model’s predictions and identify modifiable and intervenable determinants of diabetes medication adherence. Medication adherence promotion interventions may benefit from content targeting patients’ medication adherence-related information, motivation, and behavioral skills and assessing the degree to which change in these determinants leads to changes in medication adherence behavior. PMID:24598245

Empirical validation of the information-motivation-behavioral skills model of diabetes medication adherence: a framework for intervention.

PubMed

Mayberry, Lindsay S; Osborn, Chandra Y

2014-01-01

Suboptimal adherence to diabetes medications is prevalent and associated with unfavorable health outcomes, but it remains unclear what intervention content is necessary to effectively promote medication adherence in diabetes. In other disease contexts, the Information-Motivation-Behavioral skills (IMB) model has effectively explained and promoted medication adherence and thus may have utility in explaining and promoting adherence to diabetes medications. We tested the IMB model's hypotheses in a sample of adults with type 2 diabetes. Participants (N = 314) completed an interviewer-administered survey and A1C test. Structural equation models tested the effects of diabetes medication adherence-related information, motivation, and behavioral skills on medication adherence and the effect of medication adherence on A1C. The IMB elements explained 41% of the variance in adherence, and adherence explained 9% of the variance in A1C. As predicted, behavioral skills had a direct effect on adherence (β = 0.59; P < 0.001) and mediated the effects of information (indirect effect 0.08 [0.01-0.15]) and motivation (indirect effect 0.12 [0.05-0.20]) on adherence. Medication adherence significantly predicted glycemic control (β = -0.30; P < 0.001). Neither insulin status nor regimen complexity was associated with adherence, and neither moderated associations between the IMB constructs and adherence. The results support the IMB model's predictions and identify modifiable and intervenable determinants of diabetes medication adherence. Medication adherence promotion interventions may benefit from content targeting patients' medication adherence-related information, motivation, and behavioral skills and assessing the degree to which change in these determinants leads to changes in medication adherence behavior.

Write Procedures That Work.

ERIC Educational Resources Information Center

Cubberley, Carol W.

1991-01-01

Discusses written procedures that explain library tasks and describes methods for writing them clearly and coherently. The use of appropriate terminology and vocabulary is discussed; the value of illustrations, typography, and format to enhance the visual effect is explained; the intended audience is considered; and examples are given. (seven…

Solar system history as recorded in the Saturnian ring structure

NASA Technical Reports Server (NTRS)

Alfven, H.

1983-01-01

Holberg's analysis of the Voyager Saturn photographs in reflected and transparent light, and occultation data of stars seen through the rings are discussed. A hyperfine structure with 10,000 ringlets can be explained by the Baxter-Thompson negative diffusion. This gives the ringlets a stability which makes it possible to interpret them as fossils which originated at cosmogonic times. It is shown that the bulk structure can be explained by the combined cosmogonic shadows of the satellites Mimas and Janus and the Shepherd satellites. This structure originated at the transition from the plasma phase to the planetesimal phase. The shadows are not simple void regions but exhibit a characteristic signature. Parts of the fine structure, explained by Holberg as resonances with satellites, are interpreted as cosmogonic shadow effects. However, there are a number of ringlets which can neither be explained by cosmogonic nor by resonance effects. Analysis of ring data can reconstruct the plasma-planetesimal transition with an accuracy of a few percent. Previously announced in STAR as N84-12013

Solar system history as recorded in the Saturnian ring structure

NASA Technical Reports Server (NTRS)

Alfven, H.

1983-01-01

Holberg's analysis of the Voyager Saturn photographs in reflected and transparent light, and occultation data of stars seen through the rings are discussed. A hyperfine structure, with 10,000 ringlets can be explained by the Baxter-Thompson negative diffusion. This gives the ringlets a stability which makes it possible to interpret them as fossils, which originated at cosmogonic times. It is shown that the bulk structure can be explained by the combined cosmogonic shadows of the satellites Mimas, Janus and the Shepherd satellites. This structure originated at the transition from the plasma phase to the planetesimal phase. The shadows are not simple void regions but exhibit a characteristic signature. Parts of the fine structure, explained by Holberg as resonances with satellites, are interpreted as cosmogonic shadow effects. However, there are a number of ringlets which can neither be explained by cosmogonic nor by resonance effects. Analysis of ring data can reconstruct the plasma-planetesimal transition with an accuracy of a few percent.

Summary Report of Mission Acceleration Measurements for STS-62, Launched 4 March 1994

NASA Technical Reports Server (NTRS)

Rogers, Melissa J. B.; Delombard, Richard

1994-01-01

The second mission of the United States Microgravity Payload on-board the STS-62 mission was supported with three accelerometer instruments: the Orbital Acceleration Research Experiment (OARE) and two units of the Space Acceleration Measurements System (SAMS). The March 4, 1994 launch was the fourth successful mission for OARE and the ninth successful mission for SAMS. The OARE instrument utilizes a sensor for very low frequency measurements below one Hertz. The accelerations in this frequency range are typically referred to as quasisteady accelerations. One of the SAMS units had two remote triaxial sensor heads mounted on the forward MPESS structure between two furnance experiments, MEPHISTO and AADSF. These triaxial heads had low-pass filter cut-off frequencies at 10 and 25 Hz. The other SAMS unit utilized three remote triaxial sensor heads. Two of the sensor heads were mounted on the aft MPESS structure between the two experiments IDGE and ZENO. These triaxial heads had low-pass filter cut-off frequencies at 10 and 25 Hz. The third sensor head was mounted on the thermostat housing inside the IDGE experiment container. This triaxial head had a low-pass filter cut-off frequency at 5 Hz. This report is prepared to furnish interested experiment investigators with a guide to evaluating the acceleration environment during STS-62 and as a means of identifying areas which require further study. To achieve this purpose, various pieces of information are included, such as an overview of the STS-62 mission, a description of the accelerometer system flown on STS-62, some specific analysis of the accelerometer data in relation to the various mission activities, and an overview of the low-gravity environment during the entire mission. An evaluation form is included at the end of the report to solicit users' comments about the usefulness of this series of reports.

Two-body wear rate of CAD/CAM resin blocks and their enamel antagonists.

PubMed

Stawarczyk, Bogna; Özcan, Mutlu; Trottmann, Albert; Schmutz, Felix; Roos, Malgorzata; Hämmerle, Christoph

2013-05-01

Computer-aided design and computer-aided manufacturing (CAD/CAM) resins exhibit good mechanical properties and can be used as long-term restorations. The wear rate of such resins and their enamel antagonists is unknown. The purpose of this study was to test and compare the 2-body wear rate of CAD/CAM resin blocks. Wear specimens (N=42, n=6) were made from 5 CAD/CAM resins: ZENO PMMA (ZP), artBloc Temp (AT), Telio CAD (TC), Blanc High-class (HC), CAD-Temp (CT); 1 manually polymerized resin: Integral esthetic press (negative control group, IEP); and 1 glass-ceramic: VITA Mark II (positive control group, VM2). The specimens for the wear resistance were aged in a thermomechanical loading machine (49 N, 1.67 Hz, 5/50°C) with human enamel antagonists. The material loss of all specimens before, during, and after aging was evaluated with a 3DS profilometer. The measured material loss data of all tested groups were statistically evaluated with linear mixed model analysis (a=.05). Manually polymerized resin showed significantly higher material wear (P<.001) than all other tested groups. Glass-ceramic showed significantly lower wear values (P<.001) than CAD/CAM resins ZP, AT, HC, CT, and IES. CAD/CAM resin TC was not significantly different from the positive control group. Glass-ceramic showed the highest enamel wear values (P<.001) of all tested resins. No differences were found in the enamel wear among all resins. The glass-ceramic group showed damage in the form of cracks on the worn enamel surface in 50% of specimens. CAD/CAM resins showed lower wear rates than those conventionally polymerized. Only one CAD/CAM resin, TC, presented material wear values comparable with glass-ceramic. The tested glass-ceramic developed cracks in the enamel antagonist and showed the highest enamel wear values of all other tested groups. Copyright © 2013 The Editorial Council of the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Age, education, and the gender gap in the sense of control.

PubMed

Slagsvold, Britt; Sørensen, Annemette

2008-01-01

High sense of control is related to benefits in many aspects of life, and education is known to be strongly related to sense of control. In this article we explore why women tend to feel a lower sense of control than men, and why the sense of control tends to be lower among the elderly than among younger people. In particular we explore the role played by education in explaining age- and gender differences in sense of control. The analysis is based on data from the first wave of the Norwegian NorLAG study, with a representative sample of adults aged 40-79 in 30 municipalities. We find that education accounts for some of the age and gender differences in sense of control, but the mediating effects of education are rather modest. We find an increasing gender gap in sense of control with age, and this increasing gap is completely explained by differences in education. Gender differences in sense of control is explained completely by four factors, which are related to resources and power; physical health, education, living with a partner, and leadership experience. Age differences in sense of control are only partially explained. Education, physical health and employment status cuts the age effect on sense of control to half. The effect of education on sense of control is partly mediated through what we suggest are tangible benefits of education, namely health, employment, and leadership experience. Education also influences individuals through socialization mechanisms. We view agentive orientation as a psychological benefit of education, and measure this characteristic with Bem's (1981) sex-role scale on masculinity. Agentive orientation completely explains the remaining effect of education on sense of control.

[Professor MA Ji-xing and Acupuncture Scientification at the Primary Stage of Establishment of the People's Republic of China].

PubMed

Huo, Rui-li; Zhu, Ling; Yang, Feng

2015-08-01

In the initial stage (1950s) of the establishment of the People's Republic of China, the Pavlov's theory played an important influence on Chinese biology and medical science fields. At that time, many schools or colleges of traditional Chinese medicine were set up one after another, the first edition of teaching materials or textbook was complete, and a lot of advanced training courses and training classes were developed. In that specific period of "acupuncture scientification", Mr. MA Ji-xing, a professor from China Academy of Traditional Chinese Medicine, is a representative scholar who employed Pavlov's theory to make a scientific explanation about the underlying physiological mechanisms of acupuncture-moxibustion therapy. For example, he employed nerve network or nerve system to explain topical acupuncture stimulation and distal stimulation to induce local effect or distal curative effect, employed the cutaneous-visceral reflex to explain the therapeutic effect of acu-moxibustion for visceral disorders, used the viscera-cutaneous reflex to explain the tender point (sensitized region) or Ashi-point, used the "predominant factor mechanism" or excitation transfer of the stimulated non-sensitized cutaneous region close to the diseased locus to explain the pain-relief of acupuncture stimulation, used the stimulation strength, duration, frequency and distance (to the locus) to explain the needling reinforcing or reducing effect, and so on and so forth. He wrote many articles and books about acupuncturology, one of which was named Jianyao Zhenjiu Xue (Concise Acupuncturology), a well-known demonstration teaching material for advanced training courses, inducing a significant influence on the acu-moxibustion field in both academic field and clinical practice. Looking back this period of history may provide a helpful reference for current research on academic development of acupuncturology.

Estimating and explaining the effect of education and income on head and neck cancer risk: INHANCE consortium pooled analysis of 31 case-control studies from 27 countries

PubMed Central

Conway, David I.; Brenner, Darren R.; McMahon, Alex D.; Macpherson, Lorna M.D.; Agudo, Antonio; Ahrens, Wolfgang; Bosetti, Cristina; Brenner, Hermann; Castellsague, Xavier; Chen, Chu; Curado, Maria Paula; Curioni, Otávio A.; Maso, Luigino Dal; Daudt, Alexander W.; de Gois Filho, José F.; D'Souza, Gypsyamber; Edefonti, Valeria; Fabianova, Eleonora; Fernandez, Leticia; Franceschi, Silvia; Gillison, Maura; Hayes, Richard B.; Healy, Claire M.; Herrero, Rolando; Holcatova, Ivana; Jayaprakash, Vijayvel; Kelsey, Karl; Kjaerheim, Kristina; Koifman, Sergio; La Vecchia, Carlo; Lagiou, Pagona; Lazarus, Philip; Levi, Fabio; Lissowska, Jolanta; Luce, Daniele; Macfarlane, Tatiana V.; Mates, Dana; Matos, Elena; McClean, Michael; Menezes, Ana M; Menvielle, Gwenn; Merletti, Franco; Morgenstern, Hal; Moysich, Kirsten; Müller, Heiko; Muscat, Joshua; Olshan, Andrew F.; Purdue, Mark P.; Ramroth, Heribert; Richiardi, Lorenzo; Rudnai, Peter; Schantz, Stimson; Schwartz, Stephen M.; Shangina, Oxana; Simonato, Lorenzo; Smith, Elaine; Stucker, Isabelle; Sturgis, Erich M.; Szeszenia-Dabrowska, Neonila; Talamini, Renato; Thomson, Peter; Vaughan, Thomas L.; Wei, Qingyi; Winn, Deborah M.; Wunsch-Filho, Victor; Yu, Guo-Pei; Zhang, Zuo-Feng; Zheng, Tongzhang; Znaor, Ariana; Boffetta, Paolo; Chuang, Shu-Chun; Ghodrat, Marianoosh; Lee, Yuan-Chin Amy; Hashibe, Mia; Brennan, Paul

2015-01-01

Low socioeconomic status has been reported to be associated with head and neck cancer risk. However, previous studies have been too small to examine the associations by cancer subsite, age, sex, global region and calendar time and to explain the association in terms of behavioral risk factors. Individual participant data of 23,964 cases with head and neck cancer and 31,954 controls from 31 studies in 27 countries pooled with random effects models. Overall, low education was associated with an increased risk of head and neck cancer (OR = 2.50; 95% CI = 2.02 – 3.09). Overall one-third of the increased risk was not explained by differences in the distribution of cigarette smoking and alcohol behaviors; and it remained elevated among never users of tobacco and nondrinkers (OR = 1.61; 95% CI = 1.13 – 2.31). More of the estimated education effect was not explained by cigarette smoking and alcohol behaviors: in women than in men, in older than younger groups, in the oropharynx than in other sites, in South/Central America than in Europe/North America and was strongest in countries with greater income inequality. Similar findings were observed for the estimated effect of low versus high household income. The lowest levels of income and educational attainment were associated with more than 2-fold increased risk of head and neck cancer, which is not entirely explained by differences in the distributions of behavioral risk factors for these cancers and which varies across cancer sites, sexes, countries and country income inequality levels. PMID:24996155

Explaining compound generalization in associative and causal learning through rational principles of dimensional generalization.

PubMed

Soto, Fabian A; Gershman, Samuel J; Niv, Yael

2014-07-01

How do we apply learning from one situation to a similar, but not identical, situation? The principles governing the extent to which animals and humans generalize what they have learned about certain stimuli to novel compounds containing those stimuli vary depending on a number of factors. Perhaps the best studied among these factors is the type of stimuli used to generate compounds. One prominent hypothesis is that different generalization principles apply depending on whether the stimuli in a compound are similar or dissimilar to each other. However, the results of many experiments cannot be explained by this hypothesis. Here, we propose a rational Bayesian theory of compound generalization that uses the notion of consequential regions, first developed in the context of rational theories of multidimensional generalization, to explain the effects of stimulus factors on compound generalization. The model explains a large number of results from the compound generalization literature, including the influence of stimulus modality and spatial contiguity on the summation effect, the lack of influence of stimulus factors on summation with a recovered inhibitor, the effect of spatial position of stimuli on the blocking effect, the asymmetrical generalization decrement in overshadowing and external inhibition, and the conditions leading to a reliable external inhibition effect. By integrating rational theories of compound and dimensional generalization, our model provides the first comprehensive computational account of the effects of stimulus factors on compound generalization, including spatial and temporal contiguity between components, which have posed long-standing problems for rational theories of associative and causal learning. (c) 2014 APA, all rights reserved.

Explaining Compound Generalization in Associative and Causal Learning Through Rational Principles of Dimensional Generalization

PubMed Central

Soto, Fabian A.; Gershman, Samuel J.; Niv, Yael

2014-01-01

How do we apply learning from one situation to a similar, but not identical, situation? The principles governing the extent to which animals and humans generalize what they have learned about certain stimuli to novel compounds containing those stimuli vary depending on a number of factors. Perhaps the best studied among these factors is the type of stimuli used to generate compounds. One prominent hypothesis is that different generalization principles apply depending on whether the stimuli in a compound are similar or dissimilar to each other. However, the results of many experiments cannot be explained by this hypothesis. Here we propose a rational Bayesian theory of compound generalization that uses the notion of consequential regions, first developed in the context of rational theories of multidimensional generalization, to explain the effects of stimulus factors on compound generalization. The model explains a large number of results from the compound generalization literature, including the influence of stimulus modality and spatial contiguity on the summation effect, the lack of influence of stimulus factors on summation with a recovered inhibitor, the effect of spatial position of stimuli on the blocking effect, the asymmetrical generalization decrement in overshadowing and external inhibition, and the conditions leading to a reliable external inhibition effect. By integrating rational theories of compound and dimensional generalization, our model provides the first comprehensive computational account of the effects of stimulus factors on compound generalization, including spatial and temporal contiguity between components, which have posed longstanding problems for rational theories of associative and causal learning. PMID:25090430

Plant community responses to simultaneous changes in temperature, nitrogen availability, and invasion.

PubMed

Gornish, Elise S; Miller, Thomas E

2015-01-01

Increasing rates of change in climate have been observed across the planet and have contributed to the ongoing range shifts observed for many species. Although ecologists are now using a variety of approaches to study how much and through what mechanisms increasing temperature and nutrient pollution may influence the invasions inherent in range shifts, accurate predictions are still lacking. In this study, we conducted a factorial experiment, simultaneously manipulating warming, nitrogen addition and introduction of Pityopsis aspera, to determine how range-shifting species affect a plant community. We quantified the resident community using ordination scores, then used structural equation modeling to examine hypotheses related to how plants respond to a network of experimental treatments and environmental variables. Variation in soil pH explained plant community response to nitrogen addition in the absence of invasion. However, in the presence of invasion, the direct effect of nitrogen on the community was negligible and soil moisture was important for explaining nitrogen effects. We did not find effects of warming on the native plant community in the absence of invasion. In the presence of invasion, however, warming had negative effects on functional richness directly and invasion and herbivory explained the overall positive effect of warming on the plant community. This work highlights the variation in the biotic and abiotic factors responsible for explaining independent and collective climate change effects over a short time scale. Future work should consider the complex and non-additive relationships among factors of climate change and invasion in order to capture more ecologically relevant features of our changing environment.

Effects of sugars on lipid bilayers during dehydration--SAXS/WAXS measurements and quantitative model.

PubMed

Lenné, Thomas; Garvey, Christopher J; Koster, Karen L; Bryant, Gary

2009-02-26

We present an X-ray scattering study of the effects of dehydration on the bilayer and chain-chain repeat spacings of dipalmitoylphosphatidylcholine bilayers in the presence of sugars. The presence of sugars has no effect on the average spacing between the phospholipid chains in either the fluid or gel phase. Using this finding, we establish that for low sugar concentrations only a small amount of sugar exclusion occurs. Under these conditions, the effects of sugars on the membrane transition temperatures can be explained quantitatively by the reduction in hydration repulsion between bilayers due to the presence of the sugars. Specific bonding of sugars to lipid headgroups is not required to explain this effect.

Associative Accounts of Recovery-from-Extinction Effects

PubMed Central

McConnell, Bridget L.; Miller, Ralph R.

2014-01-01

Recovery-from-extinction effects (e.g., spontaneous recovery, renewal, reinstatement, and facilitated reacquisition) have become the focus of much research in recent years. However, despite a great deal of empirical data, there are few theoretical explanations for these effects. This paucity poses a severe limitation on our understanding of these behavioral effects, impedes advances in uncovering neural mechanisms of response recovery, and reduces our potential to prevent relapse after exposure therapy. Towards correcting this oversight, this review takes prominent models of associative learning that have been used in the past and continue to be used today to explain Pavlovian conditioning and extinction, and assesses how each model can be applied to account for recovery-from-extinction effects. The models include the Rescorla-Wagner (1972) model, Mackintosh's (1975) attentional model, Pearce and Hall's (1980) attentional model, Wagner's (1981) SOP model, Pearce's (1987) configural model, McLaren and Mackintosh's (2002) elemental model, and Stout and Miller's (2007) SOCR (comparator hypothesis) model. Each model is assessed for how well it explains or does not explain the various recovery-from-extinction phenomena. We offer some suggestions for how the models might be modified to account for these effects in those instances in which they initially fail. PMID:24707062

Precise low cost chain gears for heliostats

NASA Astrophysics Data System (ADS)

Liedke, Phillip; Lewandowski, Arkadiusz; Pfahl, Andreas; Hölle, Erwin

2016-05-01

This work investigates the potential of chain gears as precise and low cost driving systems for rim drive heliostats. After explaining chain gear basics the polygon effect and chain lengthening are investigated. The polygon effect could be measured by a heliostat with chain rim gear and the chain lengthening with an accordant test set up. Two gear stages are scope of this work: a rim gear and an intermediate gear. Dimensioning, pretensioning and designing for both stages are explained.

Meta-analysis of the effectiveness of chronic care management for diabetes: investigating heterogeneity in outcomes.

PubMed

Elissen, Arianne M J; Steuten, Lotte M G; Lemmens, Lidwien C; Drewes, Hanneke W; Lemmens, Karin M M; Meeuwissen, Jolanda A C; Baan, Caroline A; Vrijhoef, Hubertus J M

2013-10-01

The study aims to support decision making on how best to redesign diabetes care by investigating three potential sources of heterogeneity in effectiveness across trials of diabetes care management. Medline, CINAHL and PsycInfo were searched for systematic reviews and empirical studies focusing on: (1) diabetes mellitus; (2) adult patients; and (3) interventions consisting of at least two components of the chronic care model (CCM). Systematic reviews were analysed descriptively; empirical studies were meta-analysed. Pooled effect measures were estimated using a meta-regression model that incorporated study quality, length of follow-up and number of intervention components as potential predictors of heterogeneity in effects. Overall, reviews (n = 15) of diabetes care programmes report modest improvements in glycaemic control. Empirical studies (n = 61) show wide-ranging results on HbA1c, systolic blood pressure and guideline adherence. Differences between studies in methodological quality cannot explain this heterogeneity in effects. Variety in length of follow-up can explain (part of) the variability, yet not across all outcomes. Diversity in the number of included intervention components can explain 8-12% of the heterogeneity in effects on HbA1c and systolic blood pressure. The outcomes of chronic care management for diabetes are generally positive, yet differ considerably across trials. The most promising results are attained in studies with limited follow-up (<1 year) and by programmes including more than two CCM components. These factors can, however, explain only part of the heterogeneity in effectiveness between studies. Other potential sources of heterogeneity should be investigated to ensure implementation of evidence-based improvements in diabetes care. © 2012 John Wiley & Sons Ltd.

Carbonic Anhydrase, Calcification Dynamics and Stable Isotope Vital Effects: Deep Sea Corals and Beyond

NASA Astrophysics Data System (ADS)

Chen, S.; Gagnon, A. C.; Adkins, J. F.

2017-12-01

The stable isotope compositions of biogenic carbonates have been used for paleoceanographic and paleoclimatic reconstructions for decades, and produced some of the most iconic records in the field. However, we still lack a fully mechanistic understanding of the stable isotope proxies, especially the biological overprint on the environmental signals termed "vital effects". A ubiquitous feature of stable isotope vital effects in marine calcifying organisms is a strong correlation between δ18O and δ13C in a range of values that are depleted from equilibrium. Two mechanisms have been proposed to explain this correlation, one based on kinetic isotope effects during CO2(aq)-HCO3- inter-conversion, the other based on equilibrium isotope exchange during pH dependent speciation of the dissolved inorganic carbon pool. Neither mechanism explains all the stable isotope features observed in biogenic carbonates. Here we present a fully kinetic model of biomineralization and its isotope effects using deep sea corals as a test organism. A key component of our model is the consideration of the enzyme carbonic anhydrase in catalyzing the CO2(aq)-HCO3- inter-conversion reactions in the extracellular calcifying fluid (ECF). We find that the amount of carbonic anhydrase not only modulates the carbonate chemistry of the calcifying fluid, but also helps explain the slope of the δ18O-δ13C correlation. With this model, we are not only able to fit deep sea coral data, but also explain the stable isotope vital effects of other calcifying organisms. This fully kinetic model of stable isotope vital effects and the underlying calcification dynamics may also help us better understand mechanisms of other paleoceanographic tracers in biogenic carbonates, including boron isotopes and trace metal proxies.

Has aerobic exercise effect on pain perception in persons with migraine and coexisting tension-type headache and neck pain? A randomized, controlled, clinical trial.

PubMed

Krøll, L S; Sjödahl Hammarlund, C; Gard, G; Jensen, R H; Bendtsen, L

2018-04-10

A large subset of persons with migraine suffers from coexisting tension-type headache and neck pain which may adversely affect the prognosis of migraine. Aerobic exercise has been shown to decrease migraine burden in these persons. Therefore, the aim of this study was to investigate whether the effect of aerobic exercise in persons with migraine and coexisting tension-type headache and neck pain can be explained by changes in pain perception. Seventy consecutively recruited persons with migraine and coexisting tension-type headache and neck pain were randomized into exercise group or control group. Aerobic exercise consisted of bike/cross-trainer/brisk walking for 45 min, three times/week for 3 months. Controls continued their usual daily activities. Pericranial tenderness, pain thresholds, supra-thresholds and temporal summation were assessed at baseline, after treatment and at follow-up (6 months from baseline). Fifty-two persons with migraine and coexisting tension-type headache and neck pain completed the study. Aerobic exercise did not induce consistent changes in nociceptive pathways measured by pericranial tenderness, pressure pain thresholds and sensitivity to electrical stimulation. The effect of aerobic exercise cannot be explained by measurable effects on the pain modulation system. Thus, the positive effect on migraine burden may rather be explained by positive alteration of avoidance behaviour. Aerobic exercise can be recommended as a safe and inexpensive migraine treatment strategy. This study adds further knowledge about the positive effect of aerobic exercise for persons with migraine and coexisting tension-type headache and neck pain. This effect cannot be measured by changes in pain modulation, but may rather be explained by positive alteration of avoidance behaviour. © 2018 European Pain Federation - EFIC®.

EXPOSURE TO AREA-LEVEL PRETERM BIRTH DISPARITY AND EFFECTS ON BIRTH OUTCOMES

EPA Science Inventory

Black–white disparity in preterm birth (PTB) is persistent and not explained by individual factors. Given that exposure to inequality is associated with increased risk of adverse health, we examined PTB risk (birth <37 weeks gestational age) explained by living in U.S. census tra...

Your World, My World.

ERIC Educational Resources Information Center

Environmental Protection Agency, Washington, DC.

Americans of all ages are concerned with the effects of pollution on the environment. This booklet is designed to explain to students the environmental problems related with pollution and its control. The role of the Environmental Protection Agency (EPA) in pollution control is defined and its goals explained. Topics of discussion include clean…

Setting of Classroom Environments for Hearing Impaired Children

ERIC Educational Resources Information Center

Turan, Zerrin

2007-01-01

This paper aims to explain effects of acoustical environments in sound perception of hearing impaired people. Important aspects of sound and hearing impairment are explained. Detrimental factors in acoustic conditions for speech perception are mentioned. Necessary acoustic treatment in classrooms and use of FM systems to eliminate these factors…

Managing Corporate Risk through Better Knowledge Management

ERIC Educational Resources Information Center

Neef, Dale

2005-01-01

Purpose: To explain how progressive companies are using a combination of knowledge and risk management (KRM) systems and techniques in order to help them to prevent, or respond most effectively to, ethical or reputation-damaging incidents. Design/methodology/approach: The paper explains KRM, develops a corporate integrity framework, and then…

Mimesis: Linking Postmodern Theory to Human Behavior

ERIC Educational Resources Information Center

Dybicz, Phillip

2010-01-01

This article elaborates mimesis as a theory of causality used to explain human behavior. Drawing parallels to social constructionism's critique of positivism and naturalism, mimesis is offered as a theory of causality explaining human behavior that contests the current dominance of Newton's theory of causality as cause and effect. The contestation…

Landscape characteristics and coho salmon (Oncorhynchus kisutch) distributions: explaining abundance versus occupancy

Treesearch

E.A. Steel; D.W. Jensen; K.M. Burnett; K. Christiansen; J.C. Firman; B.E. Feist; K.J. Anlauf; D.P. Larsen

2012-01-01

Distribution of fishes, both occupancy and abundance, is often correlated with landscape-scale characteristics (e.g., geology, climate, and human disturbance). Understanding these relationships is essential for effective conservation of depressed populations. We used landscape characteristics to explain the distribution of coho salmon (Oncorhynchus kisutch...

A model of the pre-assessment learning effects of assessment is operational in an undergraduate clinical context

PubMed Central

2012-01-01

Background No validated model exists to explain the learning effects of assessment, a problem when designing and researching assessment for learning. We recently developed a model explaining the pre-assessment learning effects of summative assessment in a theory teaching context. The challenge now is to validate this model. The purpose of this study was to explore whether the model was operational in a clinical context as a first step in this process. Methods Given the complexity of the model, we adopted a qualitative approach. Data from in-depth interviews with eighteen medical students were subject to content analysis. We utilised a code book developed previously using grounded theory. During analysis, we remained alert to data that might not conform to the coding framework and open to the possibility of deploying inductive coding. Ethical clearance and informed consent were obtained. Results The three components of the model i.e., assessment factors, mechanism factors and learning effects were all evident in the clinical context. Associations between these components could all be explained by the model. Interaction with preceptors was identified as a new subcomponent of assessment factors. The model could explain the interrelationships of the three facets of this subcomponent i.e., regular accountability, personal consequences and emotional valence of the learning environment, with previously described components of the model. Conclusions The model could be utilized to analyse and explain observations in an assessment context different to that from which it was derived. In the clinical setting, the (negative) influence of preceptors on student learning was particularly prominent. In this setting, learning effects resulted not only from the high-stakes nature of summative assessment but also from personal stakes, e.g. for esteem and agency. The results suggest that to influence student learning, consequences should accrue from assessment that are immediate, concrete and substantial. The model could have utility as a planning or diagnostic tool in practice and research settings. PMID:22420839

The attribution of work environment in explaining gender differences in long-term sickness absence: results from the prospective DREAM study.

PubMed

Labriola, Merete; Holte, Kari Anne; Christensen, Karl Bang; Feveile, Helene; Alexanderson, Kristina; Lund, Thomas

2011-09-01

To identify differences in risk of long-term sickness absence between female and male employees in Denmark and to examine to what extent differences could be explained by work environment factors. A cohort of 5026 employees (49.1% women, mean age 40.4years; 50.9% men, mean age 40.2years) was interviewed in 2000 regarding gender, age, family status, socio-economic position and psychosocial and physical work environment factors. The participants were followed for 18months in order to assess their incidence of long-term sickness absence exceeding 8 consecutive weeks. 298 workers (5.9%) received sickness absence compensation for 8weeks or more. Women had an excess risk of 37% compared to men, when adjusting for age, family status and socio-economic position. Physical work environment exposures could not explain this difference, whereas differences in psychosocial work environment exposures explained 32% of the differences in risk of long-term sickness absence between men and women, causing the effect of gender to become statistically insignificant. The combined effect of physical and psychosocial factors was similar, explaining 30% of the gender difference. Differences in psychosocial work environments in terms of emotional demands, reward at work, management quality and role conflicts, explained roughly 30% of women's excess long-term sickness absence risk. Assuming women and men had identical working conditions would leave the larger part of the gender difference in long-term sickness absence from work unexplained.

Disentangling vegetation diversity from climate–energy and habitat heterogeneity for explaining animal geographic patterns

USGS Publications Warehouse

Jimenez-Alfaro, Borja; Chytry, Milan; Mucina, Ladislav; Grace, James B.; Rejmanek, Marcel

2016-01-01

Broad-scale animal diversity patterns have been traditionally explained by hypotheses focused on climate–energy and habitat heterogeneity, without considering the direct influence of vegetation structure and composition. However, integrating these factors when considering plant–animal correlates still poses a major challenge because plant communities are controlled by abiotic factors that may, at the same time, influence animal distributions. By testing whether the number and variation of plant community types in Europe explain country-level diversity in six animal groups, we propose a conceptual framework in which vegetation diversity represents a bridge between abiotic factors and animal diversity. We show that vegetation diversity explains variation in animal richness not accounted for by altitudinal range or potential evapotranspiration, being the best predictor for butterflies, beetles, and amphibians. Moreover, the dissimilarity of plant community types explains the highest proportion of variation in animal assemblages across the studied regions, an effect that outperforms the effect of climate and their shared contribution with pure spatial variation. Our results at the country level suggest that vegetation diversity, as estimated from broad-scale classifications of plant communities, may contribute to our understanding of animal richness and may be disentangled, at least to a degree, from climate–energy and abiotic habitat heterogeneity.

Aquatic community structure in Mediterranean edge-of-field waterbodies as explained by environmental factors and the presence of pesticide mixtures.

PubMed

Pereira, Ana Santos; Dâmaso-Rodrigues, Maria Luísa; Amorim, Ana; Daam, Michiel A; Cerejeira, Maria José

2018-06-16

Studies addressing the predicted effects of pesticides in combination with abiotic and biotic factors on aquatic biota in ditches associated with typical Mediterranean agroecosystems are scarce. The current study aimed to evaluate the predicted effects of pesticides along with environmental factors and biota interactions on macroinvertebrate, zooplankton and phytoplankton community compositions in ditches adjacent to Portuguese maize and tomato crop areas. Data was analysed with the variance partitioning procedure based on redundancy analysis (RDA). The total variance in biological community composition was divided into the variance explained by the multi-substance potentially affected fraction [(msPAF) arthropods and primary producers], environmental factors (water chemistry parameters), biotic interactions, shared variance, and unexplained variance. The total explained variance reached 39.4% and the largest proportion of this explained variance was attributed to msPAF (23.7%). When each group (phytoplankton, zooplankton and macroinvertebrates) was analysed separately, biota interactions and environmental factors explained the largest proportion of variance. Results of this study indicate that besides the presence of pesticide mixtures, environmental factors and biotic interactions also considerably influence field freshwater communities. Subsequently, to increase our understanding of the risk of pesticide mixtures on ecosystem communities in edge-of-field water bodies, variations in environmental and biological factors should also be considered.

Monetary policy and the effects of oil price shocks on the Japanese economy

NASA Astrophysics Data System (ADS)

Lee, Byung Rhae

1998-12-01

The evidence of output decreases and price level increases following oil price shocks in the Japanese economy is presented in this paper. These negative effects of oil shocks are better explained by Hamilton's (1996) net oil price increase measure (NOPI) than by other oil measures. The fact that an oil shock has a statistically significant effect on the call money rate and real output and that the call money rate also has a statistically significant effect on real output appears to explain that the effects of oil price shocks on economic activity are partially attributed to contractionary monetary policy responses. The asymmetric effects of positive and negative oil shocks are also found in the Japanese economy and this asymmetry can also be partially explained by monetary policy responses. To assess the relative contribution of oil shocks and endogenous monetary policy responses to the economic downturns, I shut off the responses of the call money rate to oil shocks utilizing the impulse response results from the VAR model. Then, I re-run the VAR with the adjusted call money rate series. The empirical results show that around 30--40% of the negative effects of oil price shocks on the Japanese economy can be accounted for by oil shock induced monetary tightening.

Charge carrier transport in polycrystalline organic thin film based field effect transistors

NASA Astrophysics Data System (ADS)

Rani, Varsha; Sharma, Akanksha; Ghosh, Subhasis

2016-05-01

The charge carrier transport mechanism in polycrystalline thin film based organic field effect transistors (OFETs) has been explained using two competing models, multiple trapping and releases (MTR) model and percolation model. It has been shown that MTR model is most suitable for explaining charge carrier transport in grainy polycrystalline organic thin films. The energetic distribution of traps determined independently using Mayer-Neldel rule (MNR) is in excellent agreement with the values obtained by MTR model for copper phthalocyanine and pentacene based OFETs.

Genetic Background and Environment Influence the Effects of Mutations in pykF and Help Reveal Mechanisms Underlying Their Benefit

DTIC Science & Technology

2015-08-01

another trait (Losos 2011). All of these factors make it hard to identify adaptations. Mutations are the ultimate source of genetic variation that is...effects when added to the same evolved background (See Table 2.2 for results of one-way ANOVAs). Genetic background explains most (~ 88%) of the variation ...in fitness whereas the variation explained by different pykF alleles is negligible (~2%) compared to statistical noise (~8%) (Table 2.3). These

Statistics 101 for Radiologists.

PubMed

Anvari, Arash; Halpern, Elkan F; Samir, Anthony E

2015-10-01

Diagnostic tests have wide clinical applications, including screening, diagnosis, measuring treatment effect, and determining prognosis. Interpreting diagnostic test results requires an understanding of key statistical concepts used to evaluate test efficacy. This review explains descriptive statistics and discusses probability, including mutually exclusive and independent events and conditional probability. In the inferential statistics section, a statistical perspective on study design is provided, together with an explanation of how to select appropriate statistical tests. Key concepts in recruiting study samples are discussed, including representativeness and random sampling. Variable types are defined, including predictor, outcome, and covariate variables, and the relationship of these variables to one another. In the hypothesis testing section, we explain how to determine if observed differences between groups are likely to be due to chance. We explain type I and II errors, statistical significance, and study power, followed by an explanation of effect sizes and how confidence intervals can be used to generalize observed effect sizes to the larger population. Statistical tests are explained in four categories: t tests and analysis of variance, proportion analysis tests, nonparametric tests, and regression techniques. We discuss sensitivity, specificity, accuracy, receiver operating characteristic analysis, and likelihood ratios. Measures of reliability and agreement, including κ statistics, intraclass correlation coefficients, and Bland-Altman graphs and analysis, are introduced. © RSNA, 2015.

The Effects of Visual Attention Span and Phonological Decoding in Reading Comprehension in Dyslexia: A Path Analysis.

PubMed

Chen, Chen; Schneps, Matthew H; Masyn, Katherine E; Thomson, Jennifer M

2016-11-01

Increasing evidence has shown visual attention span to be a factor, distinct from phonological skills, that explains single-word identification (pseudo-word/word reading) performance in dyslexia. Yet, little is known about how well visual attention span explains text comprehension. Observing reading comprehension in a sample of 105 high school students with dyslexia, we used a pathway analysis to examine the direct and indirect path between visual attention span and reading comprehension while controlling for other factors such as phonological awareness, letter identification, short-term memory, IQ and age. Integrating phonemic decoding efficiency skills in the analytic model, this study aimed to disentangle how visual attention span and phonological skills work together in reading comprehension for readers with dyslexia. We found visual attention span to have a significant direct effect on more difficult reading comprehension but not on an easier level. It also had a significant direct effect on pseudo-word identification but not on word identification. In addition, we found that visual attention span indirectly explains reading comprehension through pseudo-word reading and word reading skills. This study supports the hypothesis that at least part of the dyslexic profile can be explained by visual attention abilities. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Small- and Large-Effect Quantitative Trait Locus Interactions Underlie Variation in Yeast Sporulation Efficiency

PubMed Central

Lorenz, Kim; Cohen, Barak A.

2012-01-01

Quantitative trait loci (QTL) with small effects on phenotypic variation can be difficult to detect and analyze. Because of this a large fraction of the genetic architecture of many complex traits is not well understood. Here we use sporulation efficiency in Saccharomyces cerevisiae as a model complex trait to identify and study small-effect QTL. In crosses where the large-effect quantitative trait nucleotides (QTN) have been genetically fixed we identify small-effect QTL that explain approximately half of the remaining variation not explained by the major effects. We find that small-effect QTL are often physically linked to large-effect QTL and that there are extensive genetic interactions between small- and large-effect QTL. A more complete understanding of quantitative traits will require a better understanding of the numbers, effect sizes, and genetic interactions of small-effect QTL. PMID:22942125

The role of organizational context and individual nurse characteristics in explaining variation in use of information technologies in evidence based practice

PubMed Central

2012-01-01

Background There is growing awareness of the role of information technology in evidence-based practice. The purpose of this study was to investigate the role of organizational context and nurse characteristics in explaining variation in nurses’ use of personal digital assistants (PDAs) and mobile Tablet PCs for accessing evidence-based information. The Promoting Action on Research Implementation in Health Services (PARIHS) model provided the framework for studying the impact of providing nurses with PDA-supported, evidence-based practice resources, and for studying the organizational, technological, and human resource variables that impact nurses’ use patterns. Methods A survey design was used, involving baseline and follow-up questionnaires. The setting included 24 organizations representing three sectors: hospitals, long-term care (LTC) facilities, and community organizations (home care and public health). The sample consisted of 710 participants (response rate 58%) at Time 1, and 469 for whom both Time 1 and Time 2 follow-up data were obtained (response rate 66%). A hierarchical regression model (HLM) was used to evaluate the effect of predictors from all levels simultaneously. Results The Chi square result indicated PDA users reported using their device more frequently than Tablet PC users (p = 0.001). Frequency of device use was explained by ‘breadth of device functions’ and PDA versus Tablet PC. Frequency of Best Practice Guideline use was explained by ‘willingness to implement research,’ ‘structural and electronic resources,’ ‘organizational slack time,’ ‘breadth of device functions’ (positive effects), and ‘slack staff’ (negative effect). Frequency of Nursing Plus database use was explained by ‘culture,’ ‘structural and electronic resources,’ and ‘breadth of device functions’ (positive effects), and ‘slack staff’ (negative). ‘Organizational culture’ (positive), ‘breadth of device functions’ (positive), and ‘slack staff ‘(negative) were associated with frequency of Lexi/PEPID drug dictionary use. Conclusion Access to PDAs and Tablet PCs supported nurses’ self-reported use of information resources. Several of the organizational context variables and one individual nurse variable explained variation in the frequency of information resource use. PMID:23276201

Time delay and noise explaining the behaviour of the cell growth in fermentation process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ayuobi, Tawfiqullah; Rosli, Norhayati; Bahar, Arifah

2015-02-03

This paper proposes to investigate the interplay between time delay and external noise in explaining the behaviour of the microbial growth in batch fermentation process. Time delay and noise are modelled jointly via stochastic delay differential equations (SDDEs). The typical behaviour of cell concentration in batch fermentation process under this model is investigated. Milstein scheme is applied for solving this model numerically. Simulation results illustrate the effects of time delay and external noise in explaining the lag and stationary phases, respectively for the cell growth of fermentation process.

Time delay and noise explaining the behaviour of the cell growth in fermentation process

NASA Astrophysics Data System (ADS)

Ayuobi, Tawfiqullah; Rosli, Norhayati; Bahar, Arifah; Salleh, Madihah Md

2015-02-01

This paper proposes to investigate the interplay between time delay and external noise in explaining the behaviour of the microbial growth in batch fermentation process. Time delay and noise are modelled jointly via stochastic delay differential equations (SDDEs). The typical behaviour of cell concentration in batch fermentation process under this model is investigated. Milstein scheme is applied for solving this model numerically. Simulation results illustrate the effects of time delay and external noise in explaining the lag and stationary phases, respectively for the cell growth of fermentation process.

Arctic Ocean Cyclostratigraphy: An Alternative to Marine Oxygen Isotope curves as measures of Cryospheric and Sea-Level History

NASA Astrophysics Data System (ADS)

Cronin, T. M.; Marzen, R.; O'Regan, M.; Dwyer, G. S.

2016-12-01

The stable isotope compositions of biogenic carbonates have been used for paleoceanographic and paleoclimatic reconstructions for decades, and produced some of the most iconic records in the field. However, we still lack a fully mechanistic understanding of the stable isotope proxies, especially the biological overprint on the environmental signals termed "vital effects". A ubiquitous feature of stable isotope vital effects in marine calcifying organisms is a strong correlation between δ18O and δ13C in a range of values that are depleted from equilibrium. Two mechanisms have been proposed to explain this correlation, one based on kinetic isotope effects during CO2(aq)-HCO3- inter-conversion, the other based on equilibrium isotope exchange during pH dependent speciation of the dissolved inorganic carbon pool. Neither mechanism explains all the stable isotope features observed in biogenic carbonates. Here we present a fully kinetic model of biomineralization and its isotope effects using deep sea corals as a test organism. A key component of our model is the consideration of the enzyme carbonic anhydrase in catalyzing the CO2(aq)-HCO3- inter-conversion reactions in the extracellular calcifying fluid (ECF). We find that the amount of carbonic anhydrase not only modulates the carbonate chemistry of the calcifying fluid, but also helps explain the slope of the δ18O-δ13C correlation. With this model, we are not only able to fit deep sea coral data, but also explain the stable isotope vital effects of other calcifying organisms. This fully kinetic model of stable isotope vital effects and the underlying calcification dynamics may also help us better understand mechanisms of other paleoceanographic tracers in biogenic carbonates, including boron isotopes and trace metal proxies.

Role of viscosity in the magnetic field effect on pyrene-DMA exciplex emission at different permittivities

NASA Astrophysics Data System (ADS)

Jana, Amit Kumar; Roy, Partha; Nath, Deb Narayan

2014-02-01

Effect of viscosity variation on the magnetic field effect in pyrene-N,N-dimethylaniline exciplex luminescence has been studied at different permittivity values. The data is compatible to the model of Krissinel et al. (1999) [10] reported earlier to explain the effect probing the escape yield of radical pairs. It is shown that the data can also be explained on the basis of a simple model. It is interesting to note that the present letter also demonstrates the positive slope of MFE with diffusivity at extremely high viscous condition as predicted by Krissinel et al. (1999) [10] which has not been observed in earlier experiments.

The Effects of Explanatory Conversations on Children's Emotion Understanding

ERIC Educational Resources Information Center

Tenenbaum, Harriet R.; Alfieri, Louis; Brooks, Patricia J.; Dunne, Guler

2008-01-01

Ninety-three children ranging in age from 5 to 8 years (M = 82.46 months, SD = 13.20) participated in a training study designed to improve their emotion understanding. Children either explained (self-explanation condition) or listened to an experimenter who explained (experimenter-explanation condition) the causes of protagonists' hidden and…

Drama in English: An Enriching Experience.

ERIC Educational Resources Information Center

Geffen, Mitzi

1998-01-01

Examines the rationale behind using musical drama in English-as-a-Second-Language classes, explaining that it is an enjoyable experience that enriches students' English while they are relaxed, working as a team, and having fun with their imaginations. The article explains the process of putting on a play and evaluates the effect such a project had…

Listening in Early Childhood: An Interdisciplinary Review of the Literature

ERIC Educational Resources Information Center

Jalongo, Mary Renck

2010-01-01

Three general purposes of research in human development are to explain, predict, and modify behavior. Studies of listening during early childhood (birth through age eight) are of particular significance to the field because they enable researchers to describe listening processes from their very origins (explain), they demonstrate the effects of…

Sexual Assault: Guidelines for Intervention by Educators.

ERIC Educational Resources Information Center

Byerly, Carolyn

This guide explains the role of educators in dealing with cases of child sexual abuse. It provides general information on the causes and consequences of the problem, suggests ways of assisting children more effectively, and explains educator's legal requirements under Washington State law for reporting child abuse. Child sexual abuse is a general…

The Roles of Explanation and Feedback in False Belief Understanding: A Microgenetic Analysis

ERIC Educational Resources Information Center

Guajardo, Nicole R.; Petersen, Rachel; Marshall, Timothy R.

2013-01-01

The authors examined effects of feedback and explanation on false belief performance. Thirty-three children (42-54 months; 15 girls, 18 boys) were randomly assigned to four treatment conditions: explanation, feedback, feedback researcher explains, and feedback child explains. Children completed false belief tasks during pretraining, 8 training…

Explaining the Effects of Communities of Pastoral Care for Students

ERIC Educational Resources Information Center

Murphy, Joseph; Holste, Linda

2016-01-01

This article explains how communities of pastoral care work. It presents an empirically forged theory in action. We examined theoretical and empirical work across the targeted area of personalization for students. We also completed what Hallinger (2012) refers to as "exhaustive review" of the field of school improvement writ large. We…

Organizing to Use Facebook Advertisements: A Planning Tool for Extension Professionals, Businesses, and Communities

ERIC Educational Resources Information Center

Barnes, James

2016-01-01

The purpose of this article is to explain how Extension professionals, businesses, and communities can use Facebook advertisements effectively. The article is a planning tool that introduces Facebook's Advertiser Help Center, explains some applicable key concepts, and suggests best practices to apply before launching a Facebook advertising…

Capital Structure and Stock Returns

ERIC Educational Resources Information Center

Welch, Ivo

2004-01-01

U.S. corporations do not issue and repurchase debt and equity to counteract the mechanistic effects of stock returns on their debt-equity ratios. Thus over one- to five-year horizons, stock returns can explain about 40 percent of debt ratio dynamics. Although corporate net issuing activity is lively and although it can explain 60 percent of debt…

Comparison of Electron Imaging Modes for Dimensional Measurements in the Scanning Electron Microscope.

PubMed

Postek, Michael T; Vladár, András E; Villarrubia, John S; Muto, Atsushi

2016-08-01

Dimensional measurements from secondary electron (SE) images were compared with those from backscattered electron (BSE) and low-loss electron (LLE) images. With the commonly used 50% threshold criterion, the lines consistently appeared larger in the SE images. As the images were acquired simultaneously by an instrument with the capability to operate detectors for both signals at the same time, the differences cannot be explained by the assumption that contamination or drift between images affected the SE, BSE, or LLE images differently. Simulations with JMONSEL, an electron microscope simulator, indicate that the nanometer-scale differences observed on this sample can be explained by the different convolution effects of a beam with finite size on signals with different symmetry (the SE signal's characteristic peak versus the BSE or LLE signal's characteristic step). This effect is too small to explain the >100 nm discrepancies that were observed in earlier work on different samples. Additional modeling indicates that those discrepancies can be explained by the much larger sidewall angles of the earlier samples, coupled with the different response of SE versus BSE/LLE profiles to such wall angles.

Pharmacokinetics and concentration-effect relationships of therapeutic monoclonal antibodies and fusion proteins.

PubMed

Ternant, David; Paintaud, Gilles

2005-09-01

Although monoclonal antibodies (mAbs) constitute a major advance in therapeutics, their pharmacokinetic (PK) and pharmacodynamic (PD) properties are not fully understood. Saturable mechanisms are thought to occur in distribution and elimination of mAbs, which are protected from degradation by the Brambell's receptor (FcRn). The binding of mAbs to their target antigen explains part of their nonlinear PK and PD properties. The interindividual variability in mAb PK can be explained by several factors, including immune response against the biodrug and differences in the number of antigenic sites. The concentration-effect relationships of mAbs are complex and dependent on their mechanism of action. Interindividual differences in mAb PD can be explained by factors such as genetics and clinical status. PK and concentration-effect studies are necessary to design optimal dosing regimens. Because of their above-mentioned characteristics, the interindividual variability in their dose-response relationships must be studied by PK-PD modelling.

A computational cognitive model of syntactic priming.

PubMed

Reitter, David; Keller, Frank; Moore, Johanna D

2011-01-01

The psycholinguistic literature has identified two syntactic adaptation effects in language production: rapidly decaying short-term priming and long-lasting adaptation. To explain both effects, we present an ACT-R model of syntactic priming based on a wide-coverage, lexicalized syntactic theory that explains priming as facilitation of lexical access. In this model, two well-established ACT-R mechanisms, base-level learning and spreading activation, account for long-term adaptation and short-term priming, respectively. Our model simulates incremental language production and in a series of modeling studies, we show that it accounts for (a) the inverse frequency interaction; (b) the absence of a decay in long-term priming; and (c) the cumulativity of long-term adaptation. The model also explains the lexical boost effect and the fact that it only applies to short-term priming. We also present corpus data that verify a prediction of the model, that is, that the lexical boost affects all lexical material, rather than just heads. Copyright © 2011 Cognitive Science Society, Inc.

Why is the sunny side always up? Explaining the spatial mapping of concepts by language use.

PubMed

Goodhew, Stephanie C; McGaw, Bethany; Kidd, Evan

2014-10-01

Humans appear to rely on spatial mappings to represent and describe concepts. The conceptual cuing effect describes the tendency for participants to orient attention to a spatial location following the presentation of an unrelated cue word (e.g., orienting attention upward after reading the word sky). To date, such effects have predominately been explained within the embodied cognition framework, according to which people's attention is oriented on the basis of prior experience (e.g., sky → up via perceptual simulation). However, this does not provide a compelling explanation for how abstract words have the same ability to orient attention. Why, for example, does dream also orient attention upward? We report on an experiment that investigated the role of language use (specifically, collocation between concept words and spatial words for up and down dimensions) and found that it predicted the cuing effect. The results suggest that language usage patterns may be instrumental in explaining conceptual cuing.

No interpretation without representation: the role of domain-specific representations and inferences in the Wason selection task.

PubMed

Fiddick, L; Cosmides, L; Tooby, J

2000-10-16

The Wason selection task is a tool used to study reasoning about conditional rules. Performance on this task changes systematically when one varies its content, and these content effects have been used to argue that the human cognitive architecture contains a number of domain-specific representation and inference systems, such as social contract algorithms and hazard management systems. Recently, however, Sperber, Cara & Girotto (Sperber, D., Cara, F., & Girotto, V. (1995). Relevance theory explains the selection task. Cognition, 57, 31-95) have proposed that relevance theory can explain performance on the selection task - including all content effects - without invoking inference systems that are content-specialized. Herein, we show that relevance theory alone cannot explain a variety of content effects - effects that were predicted in advance and are parsimoniously explained by theories that invoke domain-specific algorithms for representing and making inferences about (i) social contracts and (ii) reducing risk in hazardous situations. Moreover, although Sperber et al. (1995) were able to use relevance theory to produce some new content effects in other domains, they conducted no experiments involving social exchanges or precautions, and so were unable to determine which - content-specialized algorithms or relevance effects - dominate reasoning when the two conflict. When experiments, reported herein, are constructed so that the different theories predict divergent outcomes, the results support the predictions of social contract theory and hazard management theory, indicating that these inference systems override content-general relevance factors. The fact that social contract and hazard management algorithms provide better explanations for performance in their respective domains does not mean that the content-general logical procedures posited by relevance theory do not exist, or that relevance effects never occur. It does mean, however, that one needs a principled way of explaining which effects will dominate when a set of inputs activate more than one reasoning system. We propose the principle of pre-emptive specificity - that the human cognitive architecture should be designed so that more specialized inference systems pre-empt more general ones whenever the stimuli centrally fit the input conditions of the more specialized system. This principle follows from evolutionary and computational considerations that are common to both relevance theory and the ecological rationality approach.

Contemporary and historic factors influence differently genetic differentiation and diversity in a tropical palm

PubMed Central

da Silva Carvalho, C; Ribeiro, M C; Côrtes, M C; Galetti, M; Collevatti, R G

2015-01-01

Population genetics theory predicts loss in genetic variability because of drift and inbreeding in isolated plant populations; however, it has been argued that long-distance pollination and seed dispersal may be able to maintain gene flow, even in highly fragmented landscapes. We tested how historical effective population size, historical migration and contemporary landscape structure, such as forest cover, patch isolation and matrix resistance, affect genetic variability and differentiation of seedlings in a tropical palm (Euterpe edulis) in a human-modified rainforest. We sampled 16 sites within five landscapes in the Brazilian Atlantic forest and assessed genetic variability and differentiation using eight microsatellite loci. Using a model selection approach, none of the covariates explained the variation observed in inbreeding coefficients among populations. The variation in genetic diversity among sites was best explained by historical effective population size. Allelic richness was best explained by historical effective population size and matrix resistance, whereas genetic differentiation was explained by matrix resistance. Coalescence analysis revealed high historical migration between sites within landscapes and constant historical population sizes, showing that the genetic differentiation is most likely due to recent changes caused by habitat loss and fragmentation. Overall, recent landscape changes have a greater influence on among-population genetic variation than historical gene flow process. As immediate restoration actions in landscapes with low forest amount, the development of more permeable matrices to allow the movement of pollinators and seed dispersers may be an effective strategy to maintain microevolutionary processes. PMID:25873150

Finding missing heritability in less significant Loci and allelic heterogeneity: genetic variation in human height.

PubMed

Zhang, Ge; Karns, Rebekah; Sun, Guangyun; Indugula, Subba Rao; Cheng, Hong; Havas-Augustin, Dubravka; Novokmet, Natalija; Durakovic, Zijad; Missoni, Sasa; Chakraborty, Ranajit; Rudan, Pavao; Deka, Ranjan

2012-01-01

Genome-wide association studies (GWAS) have identified many common variants associated with complex traits in human populations. Thus far, most reported variants have relatively small effects and explain only a small proportion of phenotypic variance, leading to the issues of 'missing' heritability and its explanation. Using height as an example, we examined two possible sources of missing heritability: first, variants with smaller effects whose associations with height failed to reach genome-wide significance and second, allelic heterogeneity due to the effects of multiple variants at a single locus. Using a novel analytical approach we examined allelic heterogeneity of height-associated loci selected from SNPs of different significance levels based on the summary data of the GIANT (stage 1) studies. In a sample of 1,304 individuals collected from an island population of the Adriatic coast of Croatia, we assessed the extent of height variance explained by incorporating the effects of less significant height loci and multiple effective SNPs at the same loci. Our results indicate that approximately half of the 118 loci that achieved stringent genome-wide significance (p-value<5×10(-8)) showed evidence of allelic heterogeneity. Additionally, including less significant loci (i.e., p-value<5×10(-4)) and accounting for effects of allelic heterogeneity substantially improved the variance explained in height.

A simple microstructure return model explaining microstructure noise and Epps effects

NASA Astrophysics Data System (ADS)

Saichev, A.; Sornette, D.

2014-01-01

We present a novel simple microstructure model of financial returns that combines (i) the well-known ARFIMA process applied to tick-by-tick returns, (ii) the bid-ask bounce effect, (iii) the fat tail structure of the distribution of returns and (iv) the non-Poissonian statistics of inter-trade intervals. This model allows us to explain both qualitatively and quantitatively important stylized facts observed in the statistics of both microstructure and macrostructure returns, including the short-ranged correlation of returns, the long-ranged correlations of absolute returns, the microstructure noise and Epps effects. According to the microstructure noise effect, volatility is a decreasing function of the time-scale used to estimate it. The Epps effect states that cross correlations between asset returns are increasing functions of the time-scale at which the returns are estimated. The microstructure noise is explained as the result of the negative return correlations inherent in the definition of the bid-ask bounce component (ii). In the presence of a genuine correlation between the returns of two assets, the Epps effect is due to an average statistical overlap of the momentum of the returns of the two assets defined over a finite time-scale in the presence of the long memory process (i).

GENETIC AND ENVIRONMENTAL EFFECTS ON BODY MASS INDEX DURING ADOLESCENCE: A PROSPECTIVE STUDY AMONG FINNISH TWINS

PubMed Central

Lajunen, Hanna-Reetta; Kaprio, Jaakko; Keski-Rahkonen, Anna; Rose, Richard J.; Pulkkinen, Lea; Rissanen, Aila; Silventoinen, Karri

2009-01-01

Objective To study genetic and environmental factors affecting body mass index (BMI) and BMI phenotypic correlations across adolescence. Design Prospective, population-based, twin cohort study. Subjects and methods We used twin modeling in 2413 monozygotic and same-sex and opposite-sex dizygotic Finnish twin pairs born in 1983–1987 and assessed by self-report questionnaires at 11–12, 14, and 17 years. Results Heritability of BMI was estimated to be 0.58–0.69 among 11–12- and 14-year-old boys and girls, 0.83 among 17-year-old boys and 0.74 among girls. Common environmental effects shared by siblings were 0.15–0.24 among 11–12- and 14-year-old boys and girls but no longer discernible at 17 y. Unique environmental effects were 0.15–0.23. Additive genetic factors explained 90–96% of the BMI phenotypic correlations across adolescence, whereas unique environmental factors explained the rest. Common environment had no effect on BMI phenotypic correlations. Conclusions The genetic contribution to BMI is strong during adolescence, and it mainly explains BMI phenotypic correlations across adolescence. Common environmental factors have an effect on BMI during early adolescence, but that effect disappears by late adolescence. PMID:19337205

Estimating the mediating effect of different biomarkers on the relation of alcohol consumption with the risk of type 2 diabetes.

PubMed

Beulens, Joline W J; van der Schouw, Yvonne T; Moons, Karel G M; Boshuizen, Hendriek C; van der A, Daphne L; Groenwold, Rolf H H

2013-04-01

Moderate alcohol consumption is associated with a reduced type 2 diabetes risk, but the biomarkers that explain this relation are unknown. The most commonly used method to estimate the proportion explained by a biomarker is the difference method. However, influence of alcohol-biomarker interaction on its results is unclear. G-estimation method is proposed to accurately assess proportion explained, but how this method compares with the difference method is unknown. In a case-cohort study of 2498 controls and 919 incident diabetes cases, we estimated the proportion explained by different biomarkers on the relation between alcohol consumption and diabetes using the difference method and sequential G-estimation method. Using the difference method, high-density lipoprotein cholesterol explained the relation between alcohol and diabetes by 78% (95% confidence interval [CI], 41-243), whereas high-sensitivity C-reactive protein (-7.5%; -36.4 to 1.8) or blood pressure (-6.9; -26.3 to -0.6) did not explain the relation. Interaction between alcohol and liver enzymes led to bias in proportion explained with different outcomes for different levels of liver enzymes. G-estimation method showed comparable results, but proportions explained were lower. The relation between alcohol consumption and diabetes may be largely explained by increased high-density lipoprotein cholesterol but not by other biomarkers. Ignoring exposure-mediator interactions may result in bias. The difference and G-estimation methods provide similar results. Copyright © 2013 Elsevier Inc. All rights reserved.

Interindustry Wage Differentials and the Gender Wage Gap.

ERIC Educational Resources Information Center

Fields, Judith; Wolff, Edward N.

1995-01-01

Wages of female workers differ significantly by industry. The average woman earns about 65% as much as the average man; 12%-22% of the gap is explained by differences in patterns of interindustry wage differentials and 15%-19% by differences in gender distribution of workers. Combined industry effects explain about one-third of the gender wage…

The Power of Why: Connecting Curriculum to Students' Lives

ERIC Educational Resources Information Center

Egbert, Joy; Roe, Mary F.

2014-01-01

Student disengagement can be a major impediment to effective student learning. When parents and educators cannot provide adequate reasoning to explain the value of what is taught at home and in school, students can lose their motivation to learn and be engaged in classroom activities. In this article, the authors explain the importance of teacher…

Vampire Selfie: A Curious Case of an Absent Reflection

ERIC Educational Resources Information Center

Grossman, Joshua M.

2014-01-01

This article presents a puzzle for the optics section of an introductory course on reflections. A teacher could ask students to explain the phenomenon of the "vampire selfie" or the absent reflection. How could that be? What physics caused this curious phenomenon? The article explains light refraction and its effect on what we see and…

Why Do Things Fall? How to Explain Why Gravity Is Not a Force

ERIC Educational Resources Information Center

Stannard, Warren B.

2018-01-01

In most high school physics classes, gravity is described as an attractive force between two masses as formulated by Newton over 300 years ago. Einstein's general theory of relativity implies that gravitational effects are instead the result of a "curvature" of space-time. However, explaining why things fall without resorting to Newton's…

A Systems Approach to Effectiveness in Catholic Elementary Schools: A Replication and Extension

ERIC Educational Resources Information Center

Mitchell, Roxanne M.; Tarter, C. John

2011-01-01

This study replicated an earlier study conducted by Tarter and Hoy (2004) in which an open systems model was used to test a series of hypotheses that explained elements of school performance. Four internal system elements (structure, individual, culture, and politics) of the school were used to explain two sets of school outcomes (student…

Learning Science through the PDEODE Teaching Strategy: Helping Students Make Sense of Everyday Situations

ERIC Educational Resources Information Center

Costu, Bayram

2008-01-01

The aim of this study was to investigate effectiveness of PDEODE (Predict-Discuss-Explain-Observe-Discuss-Explain) teaching strategy in helping students make sense of everyday situations. For this, condensation concept was chosen among many science concepts since it is related to many everyday-life events. Forty-eight eleventh graders students…

An Effective Profile Based Video Browsing System for e-Learning

ERIC Educational Resources Information Center

Premaratne, S. C.; Karunaratna, D. D.; Hewagamage, K. P.

2007-01-01

E-learning has acquired a prime place in many discussions recently. A number of research efforts around the world are trying to enhance education and training through improving e-learning facilities. This paper briefly explains one such attempt aimed at designing a system to support video clips in e-learning and explains how profiles of the…

The Role of Attitudes about Vaccine Safety, Efficacy, and Value in Explaining Parents' Reported Vaccination Behavior

ERIC Educational Resources Information Center

LaVail, Katherine Hart; Kennedy, Allison Michelle

2013-01-01

Objectives: To explain vaccine confidence as it related to parents' decisions to vaccinate their children with recommended vaccines, and to develop a confidence measure to efficiently and effectively predict parents' self-reported vaccine behaviors. Method: A sample of parents with at least one child younger than 6 years ("n" = 376) was…

When Dieting Becomes Dangerous: A Guide to Understanding and Treating Anorexia and Bulimia.

ERIC Educational Resources Information Center

Michel, Deborah Marcontell; Willard, Susan G.

This book about anorexia and bulimia is written for patients and the people who care about them. It describes the symptoms and warning signs of eating disorders, explains their presumed causes and complexities, and suggests effective treatments. The book emphasizes the critical role of psychotherapy and family therapy in recovery, explains how…

Understanding Electrochemistry Concepts Using the Predict-Observe-Explain Strategy

ERIC Educational Resources Information Center

Karamustafaoglu, Sevilay; Mamlok-Naaman, Rachel

2015-01-01

The current study deals with freshman students who study at the Department of Science at the Faculty of Education. The aim of the study was to investigate the effect of teaching electrochemistry concepts using Predict-Observe-Explain (POE) strategy. The study was quasi-experimental design using 20 students each in the experimental group (EG) and…

Relational Regulation Theory: A New Approach to Explain the Link between Perceived Social Support and Mental Health

ERIC Educational Resources Information Center

Lakey, Brian; Orehek, Edward

2011-01-01

Perceived support is consistently linked to good mental health, which is typically explained as resulting from objectively supportive actions that buffer stress. Yet this explanation has difficulty accounting for the often-observed main effects between support and mental health. Relational regulation theory (RRT) hypothesizes that main effects…

An easy and effective approach to manage radiologic portable document format (PDF) files using iTunes.

PubMed

Qian, Li Jun; Zhou, Mi; Xu, Jian Rong

2008-07-01

The objective of this article is to explain an easy and effective approach for managing radiologic files in portable document format (PDF) using iTunes. PDF files are widely used as a standard file format for electronic publications as well as for medical online documents. Unfortunately, there is a lack of powerful software to manage numerous PDF documents. In this article, we explain how to use the hidden function of iTunes (Apple Computer) to manage PDF documents as easily as managing music files.

Derivation of an applied nonlinear Schroedinger equation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pitts, Todd Alan; Laine, Mark Richard; Schwarz, Jens

We derive from first principles a mathematical physics model useful for understanding nonlinear optical propagation (including filamentation). All assumptions necessary for the development are clearly explained. We include the Kerr effect, Raman scattering, and ionization (as well as linear and nonlinear shock, diffraction and dispersion). We explain the phenomenological sub-models and each assumption required to arrive at a complete and consistent theoretical description. The development includes the relationship between shock and ionization and demonstrates why inclusion of Drude model impedance effects alters the nature of the shock operator. Unclassified Unlimited Release

Absorption Heat Pump Cycles

NASA Astrophysics Data System (ADS)

Kunugi, Yoshifumi; Kashiwagi, Takao

Various advanced absorption cycles are studied, developed and invented. In this paper, their cycles are classified and arranged using the three categories: effect, stage and loop, then an outline of the cycles are explained on the Duehring diagram. Their cycles include high COP cycles for refrigerations and heat pumps, high temperature lift cycles for heat transformer, absorption-compression hybrid cycles and heat pump transformer cycle. The highest COPi is attained by the seven effect cycle. In addition, the cycles for low temperature are invented and explained. Furthermore the power generation • refrigeration cycles are illustrated.

The role of authority power in explaining procedural fairness effects.

PubMed

van Dijke, Marius; De Cremer, David; Mayer, David M

2010-05-01

Building on fairness heuristic theory, fairness theory, and trust development models, we argue that unfairly enacted procedures decrease followers' trust in the authority particularly when authorities have high power over their followers. Moreover, we expected trust to mediate procedural fairness effects on followers' attitudes (authorities' legitimacy and charisma attributed to authorities) and organizational citizenship behavior. Procedural fairness effects on these variables, as mediated by trust, should therefore also be stronger when authority power is high. The results of a single- and multisource field study and a laboratory experiment supported these predictions. These studies support the role of authority power as a theoretically and practically relevant moderator of procedural fairness effects and show that its effectiveness is explained through trust in authorities. PsycINFO Database Record (c) 2010 APA, all rights reserved.

Crying without a cause and being easily upset in two-year-olds: heritability and predictive power of behavioral problems.

PubMed

Groen-Blokhuis, Maria M; Middeldorp, Christel M; M van Beijsterveldt, Catharina E; Boomsma, Dorret I

2011-10-01

In order to estimate the influence of genetic and environmental factors on 'crying without a cause' and 'being easily upset' in 2-year-old children, a large twin study was carried out. Prospective data were available for ~18,000 2-year-old twin pairs from the Netherlands Twin Register. A bivariate genetic analysis was performed using structural equation modeling in the Mx software package. The influence of maternal personality characteristics and demographic and lifestyle factors was tested to identify specific risk factors that may underlie the shared environment of twins. Furthermore, it was tested whether crying without a cause and being easily upset were predictive of later internalizing, externalizing and attention problems. Crying without a cause yielded a heritability estimate of 60% in boys and girls. For easily upset, the heritability was estimated at 43% in boys and 31% in girls. The variance explained by shared environment varied between 35% and 63%. The correlation between crying without a cause and easily upset (r = .36) was explained both by genetic and shared environmental factors. Birth cohort, gestational age, socioeconomic status, parental age, parental smoking behavior and alcohol use during pregnancy did not explain the shared environmental component. Neuroticism of the mother explained a small proportion of the additive genetic, but not of the shared environmental effects for easily upset. Crying without a cause and being easily upset at age 2 were predictive of internalizing, externalizing and attention problems at age 7, with effect sizes of .28-.42. A large influence of shared environmental factors on crying without a cause and easily upset was detected. Although these effects could be specific to these items, we could not explain them by personality characteristics of the mother or by demographic and lifestyle factors, and we recognize that these effects may reflect other maternal characteristics. A substantial influence of genetic factors was found for the two items, which are predictive of later behavioral problems.

Litter quality versus soil microbial community controls over decomposition: a quantitative analysis

USGS Publications Warehouse

Cleveland, Cory C.; Reed, Sasha C.; Keller, Adrienne B.; Nemergut, Diana R.; O'Neill, Sean P.; Ostertag, Rebecca; Vitousek, Peter M.

2014-01-01

The possible effects of soil microbial community structure on organic matter decomposition rates have been widely acknowledged, but are poorly understood. Understanding these relationships is complicated by the fact that microbial community structure and function are likely to both affect and be affected by organic matter quality and chemistry, thus it is difficult to draw mechanistic conclusions from field studies. We conducted a reciprocal soil inoculum × litter transplant laboratory incubation experiment using samples collected from a set of sites that have similar climate and plant species composition but vary significantly in bacterial community structure and litter quality. The results showed that litter quality explained the majority of variation in decomposition rates under controlled laboratory conditions: over the course of the 162-day incubation, litter quality explained nearly two-thirds (64 %) of variation in decomposition rates, and a smaller proportion (25 %) was explained by variation in the inoculum type. In addition, the relative importance of inoculum type on soil respiration increased over the course of the experiment, and was significantly higher in microcosms with lower litter quality relative to those with higher quality litter. We also used molecular phylogenetics to examine the relationships between bacterial community composition and soil respiration in samples through time. Pyrosequencing revealed that bacterial community composition explained 32 % of the variation in respiration rates. However, equal portions (i.e., 16 %) of the variation in bacterial community composition were explained by inoculum type and litter quality, reflecting the importance of both the meta-community and the environment in bacterial assembly. Taken together, these results indicate that the effects of changing microbial community composition on decomposition are likely to be smaller than the potential effects of climate change and/or litter quality changes in response to increasing atmospheric CO2 concentrations or atmospheric nutrient deposition.

Polymorphisms of large effect explain the majority of the host genetic contribution to variation of HIV-1 virus load

PubMed Central

Coulonges, Cedric; Bartha, István; Lenz, Tobias L.; Deutsch, Aaron J.; Bashirova, Arman; Buchbinder, Susan; Carrington, Mary N.; Cossarizza, Andrea; Dalmau, Judith; De Luca, Andrea; Goedert, James J.; Gurdasani, Deepti; Haas, David W.; Herbeck, Joshua T.; Johnson, Eric O.; Kirk, Gregory D.; Lambotte, Olivier; Luo, Ma; Mallal, Simon; van Manen, Daniëlle; Martinez-Picado, Javier; Meyer, Laurence; Miro, José M.; Mullins, James I.; Obel, Niels; Poli, Guido; Sandhu, Manjinder S.; Schuitemaker, Hanneke; Shea, Patrick R.; Theodorou, Ioannis; Walker, Bruce D.; Weintrob, Amy C.; Winkler, Cheryl A.; Wolinsky, Steven M.; Raychaudhuri, Soumya; Goldstein, David B.; Telenti, Amalio; de Bakker, Paul I. W.; Zagury, Jean-François; Fellay, Jacques

2015-01-01

Previous genome-wide association studies (GWAS) of HIV-1–infected populations have been underpowered to detect common variants with moderate impact on disease outcome and have not assessed the phenotypic variance explained by genome-wide additive effects. By combining the majority of available genome-wide genotyping data in HIV-infected populations, we tested for association between ∼8 million variants and viral load (HIV RNA copies per milliliter of plasma) in 6,315 individuals of European ancestry. The strongest signal of association was observed in the HLA class I region that was fully explained by independent effects mapping to five variable amino acid positions in the peptide binding grooves of the HLA-B and HLA-A proteins. We observed a second genome-wide significant association signal in the chemokine (C-C motif) receptor (CCR) gene cluster on chromosome 3. Conditional analysis showed that this signal could not be fully attributed to the known protective CCR5Δ32 allele and the risk P1 haplotype, suggesting further causal variants in this region. Heritability analysis demonstrated that common human genetic variation—mostly in the HLA and CCR5 regions—explains 25% of the variability in viral load. This study suggests that analyses in non-European populations and of variant classes not assessed by GWAS should be priorities for the field going forward. PMID:26553974

A New Physical Constant And Its Importance To Energy Production

NASA Astrophysics Data System (ADS)

Angus, Andrew

2003-03-01

The purpose of this paper is to introduce a new physical constant symbolized by the Greek letter lambda. This paper explains how the new physical constant was derived. This paper also explains the significance of the new physical constant as an alternative explanation to Einstein's Law of Photoelectric Effect. The new physical constant leads to a deeper understanding of the nature of the photon. Furthermore, this new physical constant leads us to the existence of two types of photon, the Planck photon and the Angus photon. Finally, the author also explains the importance of this new physical constant in energy production.

Regional variation in health care utilization in Sweden - the importance of demand-side factors.

PubMed

Johansson, Naimi; Jakobsson, Niklas; Svensson, Mikael

2018-06-04

Differences in health care utilization across geographical areas are well documented within several countries. If the variation across areas cannot be explained by differences in medical need, it can be a sign of inefficiency or misallocation of public health care resources. In this observational, longitudinal panel study we use regional level data covering the 21 Swedish regions (county councils) over 13 years and a random effects model to assess to what degree regional variation in outpatient physician visits is explained by observed demand factors such as health, demography and socio-economic factors. The results show that regional mortality, as a proxy for population health, and demography do not explain regional variation in visits to primary care physicians, but explain about 50% of regional variation in visits to outpatient specialists. Adjusting for socio-economic and basic supply-side factors explains 33% of the regional variation in primary physician visits, but adds nothing to explaining the variation in specialist visits. 50-67% of regional variation remains unexplained by a large number of observable regional characteristics, indicating that omitted and possibly unobserved factors contribute substantially to the regional variation. We conclude that variations in health care utilization across regions is not very well explained by underlying medical need and demand, measured by mortality, demographic and socio-economic factors.

Sleep Deprivation Diminishes Attentional Control Effectiveness and Impairs Flexible Adaptation to Changing Conditions.

PubMed

Whitney, Paul; Hinson, John M; Satterfield, Brieann C; Grant, Devon A; Honn, Kimberly A; Van Dongen, Hans P A

2017-11-22

Insufficient sleep is a global public health problem resulting in catastrophic accidents, increased mortality, and hundreds of billions of dollars in lost productivity. Yet the effect of sleep deprivation (SD) on decision making and performance is often underestimated by fatigued individuals and is only beginning to be understood by scientists. The deleterious impact of SD is frequently attributed to lapses in vigilant attention, but this account fails to explain many SD-related problems, such as loss of situational awareness and perseveration. Using a laboratory study protocol, we show that SD individuals can maintain information in the focus of attention and anticipate likely correct responses, but their use of such a top-down attentional strategy is less effective at preventing errors caused by competing responses. Moreover, when the task environment requires flexibility, performance under SD suffers dramatically. The impairment in flexible shifting of attentional control we observed is distinct from lapses in vigilant attention, as corroborated by the specificity of the influence of a genetic biomarker, the dopaminergic polymorphism DRD2 C957T. Reduced effectiveness of top-down attentional control under SD, especially when conditions require flexibility, helps to explain maladaptive performance that is not readily explained by lapses in vigilant attention.

Effect of inter- and intragenic epistasis on the heritability of oil content in rapeseed (Brassica napus L.).

PubMed

Würschum, Tobias; Maurer, Hans Peter; Dreyer, Felix; Reif, Jochen C

2013-02-01

The loci detected by association mapping which are involved in the expression of important agronomic traits in crops often explain only a small proportion of the total genotypic variance. Here, 17 SNPs derived from 9 candidate genes from the triacylglycerol biosynthetic pathway were studied in an association analysis in a population of 685 diverse elite rapeseed inbred lines. The 685 lines were evaluated for oil content, as well as for glucosinolates, yield, and thousand-kernel weight in field trials at 4 locations. We detected main effects for most of the studied genes illustrating that genetic diversity for oil content can be exploited by the selection of favorable alleles. In addition to main effects, both intergenic and intragenic epistasis was detected that contributes to a considerable amount to the genotypic variance observed for oil content. The proportion of explained genotypic variance was doubled when in addition to main effects epistasis was considered. Therefore, a knowledge-based improvement of oil content in rapeseed should also take such favorable epistatic interactions into account. Our results suggest, that the observed high contribution of epistasis may to some extent explain the missing heritability in genome-wide association studies.

Tuned Normalization Explains the Size of Attention Modulations

PubMed Central

Ni, Amy M.; Ray, Supratim; Maunsell, John H. R.

2012-01-01

SUMMARY The effect of attention on firing rates varies considerably within a single cortical area. The firing rate of some neurons is greatly modulated by attention while others are hardly affected. The reason for this variability across neurons is unknown. We found that the variability in attention modulation across neurons in area MT of macaques can be well explained by variability in the strength of tuned normalization across neurons. The presence of tuned normalization also explains a striking asymmetry in attention effects within neurons: when two stimuli are in a neuron’s receptive field, directing attention to the preferred stimulus modulates firing rates more than directing attention to the non-preferred stimulus. These findings show that much of the neuron-to-neuron variability in modulation of responses by attention depends on variability in the way the neurons process multiple stimuli, rather than differences in the influence of top-down signals related to attention. PMID:22365552

Interplay between strain, quantum confinement, and ferromagnetism in strained ferromagnetic semiconductor (In,Fe)As thin films

NASA Astrophysics Data System (ADS)

Sasaki, Daisuke; Anh, Le Duc; Nam Hai, Pham; Tanaka, Masaaki

2014-04-01

We systematically investigated the influence of strain on the electronic structure and ferromagnetism of (In,Fe)As thin films. It is found that while the shift of the critical point energies of compressive-strained (In,Fe)As layers grown on (In1-y,Gay)As (y = 0.05, 0.1) buffer layers can be explained by the hydrostatic deformation effect (HDE) alone, those of tensile-strained (In,Fe)As layers grown on (Ga1-z,Alz)Sb (z = 0, 0.5, 1) buffer layers can be explained by the combination of HDE and the quantum confinement effect (QCE). The Curie temperature TC of the (In,Fe)As layers strongly depends on the strain, and shows a maximum for the (In,Fe)As layer grown on a GaSb buffer layer. The strain dependence of TC can be explained by the s-d exchange mechanism taking into account HDE and QCE.

The effect of occupational and workplace gender composition on sickness absence.

PubMed

Laaksonen, Mikko; Martikainen, Pekka; Rahkonen, Ossi; Lahelma, Eero

2012-02-01

To examine whether gender composition of the occupation or the workplace is associated with sickness absence, whether the gender composition accounts for the observed female excess in sickness absence, and whether gender composition explains variation in sickness absence rates between occupations and workplaces. Random effects models conducted among Helsinki employees (N = 36,395). Women and men working in women-dominated occupations and workplaces had more short-term (1 to 3 days') sickness absence. Gender composition of the occupation and the workplace partly explained gender differences in short-term but not in intermediate (4 to 14 days') and long-term (>2 weeks') absence. Gender composition also explained variation in short-term sickness absence among occupations and workplaces, but this was partly accounted for by social class, income, and job contract type. The results are consistent with the assumption that short-term sickness absence reflects cultures and norms shaping sickness absence behavior.

Thermoplastic matrix composite processing model

NASA Technical Reports Server (NTRS)

Dara, P. H.; Loos, A. C.

1985-01-01

The effects the processing parameters pressure, temperature, and time have on the quality of continuous graphite fiber reinforced thermoplastic matrix composites were quantitatively accessed by defining the extent to which intimate contact and bond formation has occurred at successive ply interfaces. Two models are presented predicting the extents to which the ply interfaces have achieved intimate contact and cohesive strength. The models are based on experimental observation of compression molded laminates and neat resin conditions, respectively. Identified as the mechanism explaining the phenomenon by which the plies bond to themselves is the theory of autohesion (or self diffusion). Theoretical predictions from the Reptation Theory between autohesive strength and contact time are used to explain the effects of the processing parameters on the observed experimental strengths. The application of a time-temperature relationship for autohesive strength predictions is evaluated. A viscoelastic compression molding model of a tow was developed to explain the phenomenon by which the prepreg ply interfaces develop intimate contact.

Tuned normalization explains the size of attention modulations.

PubMed

Ni, Amy M; Ray, Supratim; Maunsell, John H R

2012-02-23

The effect of attention on firing rates varies considerably within a single cortical area. The firing rate of some neurons is greatly modulated by attention while others are hardly affected. The reason for this variability across neurons is unknown. We found that the variability in attention modulation across neurons in area MT of macaques can be well explained by variability in the strength of tuned normalization across neurons. The presence of tuned normalization also explains a striking asymmetry in attention effects within neurons: when two stimuli are in a neuron's receptive field, directing attention to the preferred stimulus modulates firing rates more than directing attention to the nonpreferred stimulus. These findings show that much of the neuron-to-neuron variability in modulation of responses by attention depends on variability in the way the neurons process multiple stimuli, rather than differences in the influence of top-down signals related to attention. Copyright © 2012 Elsevier Inc. All rights reserved.

HIV As Trojan Exosome: Immunological Paradox Explained?

PubMed

Hildreth, James E K

2017-01-01

The HIV pandemic is still a major global challenge, despite the widespread availability of antiretroviral drugs. An effective vaccine would be the ideal approach to bringing the pandemic to an end. However, developing an effective HIV vaccine has proven to be an elusive goal. Three major human HIV vaccine trials revealed a strong trend toward greater risk of infection among vaccine recipients versus controls. A similar observation was made in a macaque SIV vaccine study. The mechanism explaining this phenomenon is not known. Here, a model is presented that may explain the troubling results of vaccine studies and an immunological paradox of HIV pathogenesis: preferential infection of HIV-specific T cells. The central hypothesis of this perspective is that as "Trojan exosomes" HIV particles can directly activate HIV-specific T cells enhancing their susceptibility to infection. Understanding the biology of HIV as an exosome may provide insights that enable novel approaches to vaccine development.

A method to estimate the contribution of regional genetic associations to complex traits from summary association statistics.

PubMed

Pare, Guillaume; Mao, Shihong; Deng, Wei Q

2016-06-08

Despite considerable efforts, known genetic associations only explain a small fraction of predicted heritability. Regional associations combine information from multiple contiguous genetic variants and can improve variance explained at established association loci. However, regional associations are not easily amenable to estimation using summary association statistics because of sensitivity to linkage disequilibrium (LD). We now propose a novel method, LD Adjusted Regional Genetic Variance (LARGV), to estimate phenotypic variance explained by regional associations using summary statistics while accounting for LD. Our method is asymptotically equivalent to a multiple linear regression model when no interaction or haplotype effects are present. It has several applications, such as ranking of genetic regions according to variance explained or comparison of variance explained by two or more regions. Using height and BMI data from the Health Retirement Study (N = 7,776), we show that most genetic variance lies in a small proportion of the genome and that previously identified linkage peaks have higher than expected regional variance.

Effect of climatological factors on respiratory syncytial virus epidemics

PubMed Central

NOYOLA, D. E.; MANDEVILLE, P. B.

2008-01-01

SUMMARY Respiratory syncytial virus (RSV) presents as yearly epidemics in temperate climates. We analysed the association of atmospheric conditions to RSV epidemics in San Luis Potosí, S.L.P., Mexico. The weekly number of RSV detections between October 2002 and May 2006 were correlated to ambient temperature, barometric pressure, relative humidity, vapour tension, dew point, precipitation, and hours of light using time-series and regression analyses. Of the variation in RSV cases, 49·8% was explained by the study variables. Of the explained variation in RSV cases, 32·5% was explained by the study week and 17·3% was explained by meteorological variables (average daily temperature, maximum daily temperature, temperature at 08:00 hours, and relative humidity at 08:00 hours). We concluded that atmospheric conditions, particularly temperature, partly explain the year to year variability in RSV activity. Identification of additional factors that affect RSV seasonality may help develop a model to predict the onset of RSV epidemics. PMID:18177520

A method to estimate the contribution of regional genetic associations to complex traits from summary association statistics

PubMed Central

Pare, Guillaume; Mao, Shihong; Deng, Wei Q.

2016-01-01

Despite considerable efforts, known genetic associations only explain a small fraction of predicted heritability. Regional associations combine information from multiple contiguous genetic variants and can improve variance explained at established association loci. However, regional associations are not easily amenable to estimation using summary association statistics because of sensitivity to linkage disequilibrium (LD). We now propose a novel method, LD Adjusted Regional Genetic Variance (LARGV), to estimate phenotypic variance explained by regional associations using summary statistics while accounting for LD. Our method is asymptotically equivalent to a multiple linear regression model when no interaction or haplotype effects are present. It has several applications, such as ranking of genetic regions according to variance explained or comparison of variance explained by two or more regions. Using height and BMI data from the Health Retirement Study (N = 7,776), we show that most genetic variance lies in a small proportion of the genome and that previously identified linkage peaks have higher than expected regional variance. PMID:27273519

What explains gender inequalities in HIV/AIDS prevalence in sub-Saharan Africa? Evidence from the demographic and health surveys.

PubMed

Sia, Drissa; Onadja, Yentéma; Hajizadeh, Mohammad; Heymann, S Jody; Brewer, Timothy F; Nandi, Arijit

2016-11-03

Women are disproportionally affected by human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) in sub-Saharan Africa (SSA). The determinants of gender inequality in HIV/AIDS may vary across countries and require country-specific interventions to address them. This study aimed to identify the socio-demographic and behavioral characteristics underlying gender inequalities in HIV/AIDS in 21 SSA countries. We applied an extension of the Blinder-Oaxaca decomposition approach to data from Demographic and Health Surveys and AIDS Indicator Surveys to quantify the differences in HIV/AIDS prevalence between women and men attributable to socio-demographic factors, sexual behaviours, and awareness of HIV/AIDS. We decomposed gender inequalities into two components: the percentage attributable to different levels of the risk factors between women and men (the "composition effect") and the percentage attributable to risk factors having differential effects on HIV/AIDS prevalence in women and men (the "response effect"). Descriptive analyses showed that the difference between women and men in HIV/AIDS prevalence varied from a low of 0.68 % (P = 0.008) in Liberia to a high of 11.5 % (P < 0.001) in Swaziland. The decomposition analysis showed that 84 % (P < 0.001) and 92 % (P < 0.001) of the higher prevalence of HIV/AIDS among women in Uganda and Ghana, respectively, was explained by the different distributions of HIV/AIDS risk factors, particularly age at first sex between women and men. In the majority of countries, however, observed gender inequalities in HIV/AIDS were chiefly explained by differences in the responses to risk factors; the differential effects of age, marital status and occupation on prevalence of HIV/AIDS for women and men were among the significant contributors to this component. In Cameroon, Guinea, Malawi and Swaziland, a combination of the composition and response effects explained gender inequalities in HIV/AIDS prevalence. The factors that explain gender inequality in HIV/AIDS in SSA vary by country, suggesting that country-specific interventions are needed. Unmeasured factors also contributed substantially to the difference in HIV/AIDS prevalence between women and men, highlighting the need for further study.

Large power factor and anomalous Hall effect and their correlation with observed linear magneto resistance in Co-doped Bi2Se3 3D topological insulator

NASA Astrophysics Data System (ADS)

Singh, Rahul; Shukla, K. K.; Kumar, A.; Okram, G. S.; Singh, D.; Ganeshan, V.; Lakhani, Archana; Ghosh, A. K.; Chatterjee, Sandip

2016-09-01

Magnetoresistance (MR), thermo power, magnetization and Hall effect measurements have been performed on Co-doped Bi2Se3 topological insulators. The undoped sample shows that the maximum MR as a destructive interference due to a π-Berry phase leads to a decrease of MR. As the Co is doped, the linearity in MR is increased. The observed MR of Bi2Se3 can be explained with the classical model. The low temperature MR behavior of Co doped samples cannot be explained with the same model, but can be explained with the quantum linear MR model. Magnetization behavior indicates the establishment of ferromagnetic ordering with Co doping. Hall effect data also supports the establishment of ferromagnetic ordering in Co-doped Bi2Se3 samples by showing the anomalous Hall effect. Furthermore, when spectral weight suppression is insignificant, Bi2Se3 behaves as a dilute magnetic semiconductor. Moreover, the maximum power factor is observed when time reversal symmetry (TRS) is maintained. As the TRS is broken the power factor value is decreased, which indicates that with the rise of Dirac cone above the Fermi level the anomalous Hall effect and linearity in MR increase and the power factor decreases.

Special health care needs explains the effect of extremely low birth weight on math but not language achievement.

PubMed

Litt, Jonathan S; Minich, Nori; Taylor, H Gerry; Hack, Maureen

2017-12-01

Extremely low birth weight (ELBW; <1kg) adolescents are at risk for special health care needs (SHCN) and poor math achievement compared to normal birth weight (NBW) peers. SHCN are associated with poor academic achievement among NBW children. We hypothesize that SHCN explain the effect of ELBW on math achievement. We compared age 14 Woodcock-Johnson Calculation standard scores between 181 ELBW infants and 115 NBW controls. Persistent SHCN included: 1) prescription medication or equipment use, 2) subspecialty or therapeutic service use, or 3) hospitalization. We used nonlinear marginal effects models to decompose the total effect of ELBW on math into the following 4 components: the effect of ELBW controlling for SHCN, the effect of SHCN controlling for ELBW, effect modification by SHCN, and mediated interaction where SHCN is both causal mediator and effect modifier. Models were adjusted for sociodemographic factors. ELBW adolescents had lower mean math scores than NBW peers (81.3 vs. 96.4). SHCN were more common among ELBW adolescents (54.1% vs. 27%). The total effect of ELBW on math scores was -15.7 points (95% CI -21.0, -10.5). The effect of birth weight alone was -7.6 points (95% CI -13.7, -1.4); the effect of SHCN alone was negligible. SHCN interaction and mediated interaction effects each accounted for 25% of the total effect. Birth weight alone explains only half of the effect of ELBW on math achievement. We found evidence of effect modification and mediation by SHCN. Understanding these explanatory pathways may lead to targeted interventions for improved outcomes. Copyright © 2017. Published by Elsevier B.V.

The impact of p53 protein core domain structural alteration on ovarian cancer survival.

PubMed

Rose, Stephen L; Robertson, Andrew D; Goodheart, Michael J; Smith, Brian J; DeYoung, Barry R; Buller, Richard E

2003-09-15

Although survival with a p53 missense mutation is highly variable, p53-null mutation is an independent adverse prognostic factor for advanced stage ovarian cancer. By evaluating ovarian cancer survival based upon a structure function analysis of the p53 protein, we tested the hypothesis that not all missense mutations are equivalent. The p53 gene was sequenced from 267 consecutive ovarian cancers. The effect of individual missense mutations on p53 structure was analyzed using the International Agency for Research on Cancer p53 Mutational Database, which specifies the effects of p53 mutations on p53 core domain structure. Mutations in the p53 core domain were classified as either explained or not explained in structural or functional terms by their predicted effects on protein folding, protein-DNA contacts, or mutation in highly conserved residues. Null mutations were classified by their mechanism of origin. Mutations were sequenced from 125 tumors. Effects of 62 of the 82 missense mutations (76%) could be explained by alterations in the p53 protein. Twenty-three (28%) of the explained mutations occurred in highly conserved regions of the p53 core protein. Twenty-two nonsense point mutations and 21 frameshift null mutations were sequenced. Survival was independent of missense mutation type and mechanism of null mutation. The hypothesis that not all missense mutations are equivalent is, therefore, rejected. Furthermore, p53 core domain structural alteration secondary to missense point mutation is not functionally equivalent to a p53-null mutation. The poor prognosis associated with p53-null mutation is independent of the mutation mechanism.

Analysing How Scientists Explain Their Research: A Rubric for Measuring the Effectiveness of Scientific Explanations

ERIC Educational Resources Information Center

Sevian, Hannah; Gonsalves, Lisa

2008-01-01

The present article presents a rubric we developed for assessing the quality of scientific explanations by science graduate students. The rubric was developed from a qualitative analysis of science graduate students' abilities to explain their own research to an audience of non-scientists. Our intention is that use of the rubric to characterise…

Science of consciousness and the hard problem

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stapp, H.P.

1996-05-22

Quantum theory is essentially a rationally coherent theory of the interaction of mind and matter, and it allows our conscious thoughts to play a causally efficacious and necessary role in brain dynamics. It therefore provides a natural basis, created by scientists, for the science of consciousness. As an illustration it is explained how the interaction of brain and consciousness can speed up brain processing, and thereby enhance the survival prospects of conscious organisms, as compared to similar organisms that lack consciousness. As a second illustration it is explained how, within the quantum framework, the consciously experienced {open_quotes}I{close_quotes} directs the actionsmore » of a human being. It is concluded that contemporary science already has an adequate framework for incorporating causally efficacious experimential events into the physical universe in a manner that: (1) puts the neural correlates of consciousness into the theory in a well defined way, (2) explains in principle how the effects of consciousness, per se, can enhance the survival prospects of organisms that possess it, (3) allows this survival effect to feed into phylogenetic development, and (4) explains how the consciously experienced {open_quotes}I{close_quotes} can direct human behaviour.« less

Long- and short-term effects of boron excess to root form and function in two tomato genotypes.

PubMed

Princi, Maria Polsia; Lupini, Antonio; Longo, Caterina; Miller, Anthony J; Sunseri, Francesco; Abenavoli, Maria Rosa

2016-12-01

Boron (B) is an essential plant nutrient, but when present in excess it is toxic. Morphological measurements were made to assess the impact of B toxicity on the growth of two different tomato hybrids, Losna and Ikram. Contrasting long and short-term B responses in these tomato hybrids, were observed. Losna showed less toxicity symptoms, maintaining higher growth and showing much less B content in both root and shoot tissues compared to Ikram. Root morphological differences did not explain the tolerance between the two hybrids. Under excess B supply, a significant inhibition on net nitrate uptake rate was observed in Ikram, but not in Losna. This effect may be explained by a decrease of nitrate transporter transcripts in Ikram, which was not measured in Losna. There was a different pattern of B transporter expression in two tomatoes and this can explain the contrasting tolerance observed. Indeed, Losna may be able to exclude or efflux B resulting in less accumulation in the shoot. Particularly, SlBOR4 expression showed significant differences between the tomato hybrids, with higher expression in Losna explaining the improved B-tolerance. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Genetic pleiotropy explains associations between musical auditory discrimination and intelligence.

PubMed

Mosing, Miriam A; Pedersen, Nancy L; Madison, Guy; Ullén, Fredrik

2014-01-01

Musical aptitude is commonly measured using tasks that involve discrimination of different types of musical auditory stimuli. Performance on such different discrimination tasks correlates positively with each other and with intelligence. However, no study to date has explored these associations using a genetically informative sample to estimate underlying genetic and environmental influences. In the present study, a large sample of Swedish twins (N = 10,500) was used to investigate the genetic architecture of the associations between intelligence and performance on three musical auditory discrimination tasks (rhythm, melody and pitch). Phenotypic correlations between the tasks ranged between 0.23 and 0.42 (Pearson r values). Genetic modelling showed that the covariation between the variables could be explained by shared genetic influences. Neither shared, nor non-shared environment had a significant effect on the associations. Good fit was obtained with a two-factor model where one underlying shared genetic factor explained all the covariation between the musical discrimination tasks and IQ, and a second genetic factor explained variance exclusively shared among the discrimination tasks. The results suggest that positive correlations among musical aptitudes result from both genes with broad effects on cognition, and genes with potentially more specific influences on auditory functions.

Suicidal ideation, depression, and conduct disorder in a sample of adolescent and young adult twins

PubMed Central

Linker, Julie; Gillespie, Nathan A; Maes, Hermine; Eaves, Lindon; Silberg, Judy L.

2012-01-01

Background The co-occurrence of suicidal ideation, depression, and conduct disturbance is likely explained in part by correlated genetic and environmental risk factors. Little is known about the specific nature of these associations. Method Structured interviews on 2814 twins from the Virginia Twin Study of Adolescent Behavioral Development (VTSABD) and young adult follow-up (YAFU) yielded data on symptoms of depression, conduct disorder and adolescent and young adult suicidal ideation. Results Univariate analyses revealed that the familial aggregation for each trait was explained by a combination of additive genetic and shared environmental effects. Suicidal ideation in adolescence was explained in part by genetic influences, but predominantly accounted for by environmental factors. A mixture of genetic and shared environmental influences explained ideation occurring in young adulthood. Multivariate analyses revealed that there are genetic and shared environmental effects common to suicidal ideation, depression, and conduct disorder. The association between adolescent suicidal ideation and CD was attributable to the same genetic and environmental risk factors for depression. Conclusions These findings underscore that prevention and intervention strategies should reflect the different underlying mechanisms involving depression and conduct disorder to assist in identifying adolescents at suicidal risk. PMID:22646517

Genetic Pleiotropy Explains Associations between Musical Auditory Discrimination and Intelligence

PubMed Central

Mosing, Miriam A.; Pedersen, Nancy L.; Madison, Guy; Ullén, Fredrik

2014-01-01

Musical aptitude is commonly measured using tasks that involve discrimination of different types of musical auditory stimuli. Performance on such different discrimination tasks correlates positively with each other and with intelligence. However, no study to date has explored these associations using a genetically informative sample to estimate underlying genetic and environmental influences. In the present study, a large sample of Swedish twins (N = 10,500) was used to investigate the genetic architecture of the associations between intelligence and performance on three musical auditory discrimination tasks (rhythm, melody and pitch). Phenotypic correlations between the tasks ranged between 0.23 and 0.42 (Pearson r values). Genetic modelling showed that the covariation between the variables could be explained by shared genetic influences. Neither shared, nor non-shared environment had a significant effect on the associations. Good fit was obtained with a two-factor model where one underlying shared genetic factor explained all the covariation between the musical discrimination tasks and IQ, and a second genetic factor explained variance exclusively shared among the discrimination tasks. The results suggest that positive correlations among musical aptitudes result from both genes with broad effects on cognition, and genes with potentially more specific influences on auditory functions. PMID:25419664

Suicidal ideation, depression, and conduct disorder in a sample of adolescent and young adult twins.

PubMed

Linker, Julie; Gillespie, Nathan A; Maes, Hermine; Eaves, Lindon; Silberg, Judy L

2012-08-01

The co-occurrence of suicidal ideation, depression, and conduct disturbance is likely explained in part by correlated genetic and environmental risk factors. Little is known about the specific nature of these associations. Structured interviews on 2,814 twins from the Virginia Twin Study of Adolescent Behavioral Development (VTSABD) and Young Adult Follow-Up (YAFU) yielded data on symptoms of depression, conduct disorder, and adolescent and young adult suicidal ideation. Univariate analyses revealed that the familial aggregation for each trait was explained by a combination of additive genetic and shared environmental effects. Suicidal ideation in adolescence was explained in part by genetic influences, but predominantly accounted for by environmental factors. A mixture of genetic and shared environmental influences explained ideation occurring in young adulthood. Multivariate analyses revealed that there are genetic and shared environmental effects common to suicidal ideation, depression, and conduct disorder. The association between adolescent suicidal ideation and CD was attributable to the same genetic and environmental risk factors for depression. These findings underscore that prevention and intervention strategies should reflect the different underlying mechanisms involving depression and conduct disorder to assist in identifying adolescents at suicidal risk. © 2012 The American Association of Suicidology.

A spectacular coronal mass ejection event and associated phenomena

NASA Astrophysics Data System (ADS)

Ma, Yuan; Li, Chun-Sheng; Song, Qian

Based on the data taken from S. G. D. and relevant simultaneous observations of solar radio bursts, gamma-ray emission and geophysical effects on June 15, 1991 the relationships among these phenomena are discussed in this paper. Through the analyses it is considered that proton events and GLE events occurred on June 15 in 1991, which were the geophysic responses caused by CME (V>=750 km/s). Simultaneous observation of the bursts at the centimetric and decimetric wavelengths can obtain the U-shape spectrum of speak fluxes, which is still one of the effective tools for predicting proton events and its production mechanism can be explained by using the acceleration of the direct current field parallel to the magnetic field in the electric current sheet formed in the process of the production of spray prominences. However, the process in which electrons are accelerated up to the high energy state remains to be explained. The whole event of June 15 1991, from the coronal matter ejection (or the spray prominences in active regions) to the production of various geophysic effects, has explained and verified.

Using a Red Team to devise countermeasures

NASA Astrophysics Data System (ADS)

Swedenburg, R. L.

1995-01-01

The ability of a defense system to operate effectively when deployed in battle is dependent on designs able to deal with countermeasures against the defense. The formation of a technical Red Team to stress the preliminary designs of the defensive system with technologically feasible and effective potential countermeasures provides a means to identify such potential countermeasures. This paper describes the experience of the U.S. Ballistic Missile Defense Organization's (BMDO) Theater Missile Defense Red Team since the Gulf War in 1991, the Red-Blue Exchange process, and the value it has provided to the designers of the U.S. Theater Missile Defense systems for developing robust systems. A wide-range of technologically feasible countermeasures has been devised, analyzed, tested for feasibility, and provided to the system developers for mitigation design. The process for independently analyzing possible susceptibilities of preliminary designs and exploiting the susceptibilities to identify possible countermeasures is explained. Designing and characterizing the Red Team's countermeasures, determining their feasibility, and analyzing their potential effectiveness against the defense are explained. A technique for the Blue Team's designers to deal with a wide range of potential countermeasures is explained.

Transcranial Electrical Stimulation

PubMed Central

Fertonani, Anna; Miniussi, Carlo

2016-01-01

In recent years, there has been remarkable progress in the understanding and practical use of transcranial electrical stimulation (tES) techniques. Nevertheless, to date, this experimental effort has not been accompanied by substantial reflections on the models and mechanisms that could explain the stimulation effects. Given these premises, the aim of this article is to provide an updated picture of what we know about the theoretical models of tES that have been proposed to date, contextualized in a more specific and unitary framework. We demonstrate that these models can explain the tES behavioral effects as distributed along a continuum from stimulation dependent to network activity dependent. In this framework, we also propose that stochastic resonance is a useful mechanism to explain the general online neuromodulation effects of tES. Moreover, we highlight the aspects that should be considered in future research. We emphasize that tES is not an “easy-to-use” technique; however, it may represent a very fruitful approach if applied within rigorous protocols, with deep knowledge of both the behavioral and cognitive aspects and the more recent advances in the application of stimulation. PMID:26873962

Verb-based versus class-based accounts of actionality effects in children's comprehension of passives.

PubMed

Gordon, P; Chafetz, J

1990-09-01

Several studies have shown that children perform worse on tests of passive comprehension when the verb is non-actional than when it is actional. Most existing accounts focus on the semantic characteristics of the class of non-action verbs in explaining this difference. An alternative is a "verb-based" account in which passives are initially learned verb by verb, and children hear fewer non-actional passives in their language input. An analysis of the passives heard by Adam, Eve and Sarah (Brown, 1973) found more actional than non-actional passives, consistent with the verb-based account. In a second study, children tested for passive comprehension were re-tested a week later. The verb-based account predicts that children should show a consistent pattern of responses for individual verbs on test and re-test. Such consistency was found, with some inconsistency due to improvement over the re-test. Further analyses showed no effects of affectedness in explaining children's problems with passives. Finally, we discuss whether a mixed model containing both verb-based and class-based mechanisms is required to explain the actionality effects.

The peer effect on pain tolerance.

PubMed

Engebretsen, Solveig; Frigessi, Arnoldo; Engø-Monsen, Kenth; Furberg, Anne-Sofie; Stubhaug, Audun; de Blasio, Birgitte Freiesleben; Nielsen, Christopher Sivert

2018-05-19

Twin studies have found that approximately half of the variance in pain tolerance can be explained by genetic factors, while shared family environment has a negligible effect. Hence, a large proportion of the variance in pain tolerance is explained by the (non-shared) unique environment. The social environment beyond the family is a potential candidate for explaining some of the variance in pain tolerance. Numerous individual traits have previously shown to be associated with friendship ties. In this study, we investigate whether pain tolerance is associated with friendship ties. We study the friendship effect on pain tolerance by considering data from the Tromsø Study: Fit Futures I, which contains pain tolerance measurements and social network information for adolescents attending first year of upper secondary school in the Tromsø area in Northern Norway. Pain tolerance was measured with the cold-pressor test (primary outcome), contact heat and pressure algometry. We analyse the data by using statistical methods from social network analysis. Specifically, we compute pairwise correlations in pain tolerance among friends. We also fit network autocorrelation models to the data, where the pain tolerance of an individual is explained by (among other factors) the average pain tolerance of the individual's friends. We find a significant and positive relationship between the pain tolerance of an individual and the pain tolerance of their friends. The estimated effect is that for every 1 s increase in friends' average cold-pressor tolerance time, the expected cold-pressor pain tolerance of the individual increases by 0.21 s (p-value: 0.0049, sample size n=997). This estimated effect is controlled for sex. The friendship effect remains significant when controlling for potential confounders such as lifestyle factors and test sequence among the students. Further investigating the role of sex on this friendship effect, we only find a significant peer effect of male friends on males, while there is no significant effect of friends' average pain tolerance on females in stratified analyses. Similar, but somewhat lower estimates were obtained for the other pain modalities. We find a positive and significant peer effect in pain tolerance. Hence, there is a significant tendency for students to be friends with others with similar pain tolerance. Sex-stratified analyses show that the only significant effect is the effect of male friends on males. Two different processes can explain the friendship effect in pain tolerance, selection and social transmission. Individuals might select friends directly due to similarity in pain tolerance, or indirectly through similarity in other confounding variables that affect pain tolerance. Alternatively, there is an influence effect among friends either directly in pain tolerance, or indirectly through other variables that affect pain tolerance. If there is indeed a social influence effect in pain tolerance, then the social environment can account for some of the unique environmental variance in pain tolerance. If so, it is possible to therapeutically affect pain tolerance through alteration of the social environment.

Improving Precautionary Communication in the EMF Field? Effects of Making Messages Consistent and Explaining the Effectiveness of Precautions.

PubMed

Boehmert, Christoph; Wiedemann, Peter; Croft, Rodney

2016-10-09

Many radiation health agencies communicate precautionary measures regarding the use of mobile communication devices, e.g. the use of a headset while talking on the phone. These precautionary messages have, however, been shown to unintentionally increase risk perceptions about radiofrequency electromagnetic fields (RF-EMFs). The current study tested two potential ways of amending precautionary messages in order to minimise this unintentional effect. Firstly, the messages' potential to be perceived as inconsistent and thereby raise suspicions was addressed; secondly, the effectiveness of the precautions was explained. An experimental design was applied in which a quota sample of 1717 Australian residents was randomly assigned to one of six message conditions. Three different risk perception measures served as dependent variables, two of them are conditional measures. The original effect of precautionary messages to amplify risk perceptions could not be replicated. Furthermore, amending precautionary messages in favour of more consistency had no effect, while explaining the effectiveness of the precautions increased conditional risk perception under the condition that no precautions are taken. This was contrary to our assumptions. We infer from these results that changing precautionary messages in terms of consistency and effectiveness in order to reduce risk perception is hardly possible. The use of conditional risk perception measures seems fruitful for studies looking at the effects of precautionary or protective messages, given that previous studies have only investigated effects on unconditional risk perception. However, the present results should not be over-interpreted as the measures' validity in the EMF context still needs further investigation.

Improving Precautionary Communication in the EMF Field? Effects of Making Messages Consistent and Explaining the Effectiveness of Precautions

PubMed Central

Boehmert, Christoph; Wiedemann, Peter; Croft, Rodney

2016-01-01

Many radiation health agencies communicate precautionary measures regarding the use of mobile communication devices, e.g. the use of a headset while talking on the phone. These precautionary messages have, however, been shown to unintentionally increase risk perceptions about radiofrequency electromagnetic fields (RF-EMFs). The current study tested two potential ways of amending precautionary messages in order to minimise this unintentional effect. Firstly, the messages’ potential to be perceived as inconsistent and thereby raise suspicions was addressed; secondly, the effectiveness of the precautions was explained. An experimental design was applied in which a quota sample of 1717 Australian residents was randomly assigned to one of six message conditions. Three different risk perception measures served as dependent variables, two of them are conditional measures. The original effect of precautionary messages to amplify risk perceptions could not be replicated. Furthermore, amending precautionary messages in favour of more consistency had no effect, while explaining the effectiveness of the precautions increased conditional risk perception under the condition that no precautions are taken. This was contrary to our assumptions. We infer from these results that changing precautionary messages in terms of consistency and effectiveness in order to reduce risk perception is hardly possible. The use of conditional risk perception measures seems fruitful for studies looking at the effects of precautionary or protective messages, given that previous studies have only investigated effects on unconditional risk perception. However, the present results should not be over-interpreted as the measures’ validity in the EMF context still needs further investigation. PMID:27735851

A balanced motor primitive framework can simultaneously explain motor learning in unimanual and bimanual movements.

PubMed

Takiyama, Ken; Sakai, Yutaka

2017-02-01

Certain theoretical frameworks have successfully explained motor learning in either unimanual or bimanual movements. However, no single theoretical framework can comprehensively explain motor learning in both types of movement because the relationship between these two types of movement remains unclear. Although our recent model of a balanced motor primitive framework attempted to simultaneously explain motor learning in unimanual and bimanual movements, this model focused only on a limited subset of bimanual movements and therefore did not elucidate the relationships between unimanual movements and various bimanual movements. Here, we extend the balanced motor primitive framework to simultaneously explain motor learning in unimanual and various bimanual movements as well as the transfer of learning effects between unimanual and various bimanual movements; these phenomena can be simultaneously explained if the mean activity of each primitive for various unimanual movements is balanced with the corresponding mean activity for various bimanual movements. Using this balanced condition, we can reproduce the results of prior behavioral and neurophysiological experiments. Furthermore, we demonstrate that the balanced condition can be implemented in a simple neural network model. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Recent development of the passive vibration control method

NASA Astrophysics Data System (ADS)

Ishida, Yukio

2012-05-01

This paper introduces new passive vibration suppression methods developed recently in our laboratory. First, two methods used to suppress steady-state resonances are explained. One is the improvement of the efficiency of a ball balancer. A simple method to eliminate the influence of friction of balls and to improve its efficiency is introduced. The other is an effective method that utilizes the discontinuous spring characteristics. Secondly, a method to eliminate unstable ranges in rotor systems is explained. Unstable ranges in an asymmetrical shaft, and in a hollow rotor partially filled with liquid, are eliminated by the discontinuous spring characteristics. Thirdly, a method to suppress self-excited oscillations is explained. Self-excited oscillations due to internal damping and rubbing are discussed. Finally, the methods of using a pendulum or roller type absorbers to suppress torsional vibrations are explained.

The Science of Colour

ERIC Educational Resources Information Center

Edwards, S. J.

1975-01-01

Provides information on how humans see color including sensitivity of the eye, spatial effects, and temporal effects, and relative to the characteristics of the human eye explains how color is measured. (GS)

Young children's reasoning about the effects of emotional and physiological states on academic performance.

PubMed

Amsterlaw, Jennifer; Lagattuta, Kristin Hansen; Meltzoff, Andrew N

2009-01-01

This study assessed young children's understanding of the effects of emotional and physiological states on cognitive performance. Five, 6-, 7-year-olds, and adults (N= 96) predicted and explained how children experiencing a variety of physiological and emotional states would perform on academic tasks. Scenarios included: (a) negative and positive emotions, (b) negative and positive physiological states, and (c) control conditions. All age groups understood the impairing effects of negative emotions and physiological states. Only 7-year-olds, however, showed adult-like reasoning about the potential enhancing effects of positive internal states and routinely cited cognitive mechanisms to explain how internal states affect performance. These results shed light on theory-of-mind development and also have significance for children's everyday school success.

Roles of context in acquisition of human instrumental learning: Implications for the understanding of the mechanisms underlying context-switch effects.

PubMed

Gámez, A Matías; León, Samuel P; Rosas, Juan M

2017-09-01

Four experiments in human instrumental learning explored the associations involving the context that develop after three trials of training on simple discriminations. Experiments 1 and 4 found a deleterious effect of switching the learning context that cannot be explained by the context-outcome binary associations commonly used to explain context-switch effects after short training in human predictive learning and in animal Pavlovian conditioning. Evidence for context-outcome (Experiment 2), context-discriminative stimulus (Experiment 3), and context-instrumental response (Experiment 4) binary associations was found within the same training paradigm, suggesting that contexts became associated with all the elements of the situation, regardless of whether those associations played a role in a specific context-switch effect detected on performance.

Economic principles in communication: an experimental study.

PubMed

De Jaegher, Kris; Rosenkranz, Stephanie; Weitzel, Utz

2014-12-21

This paper experimentally investigates how economic principles affect communication. In a simple sender-receiver game with common interests over payoffs, the sender can send a signal without a pre-given meaning in an infrequent or frequent state of the world. When the signal is costly, several theories (focal point theory, the intuitive criterion, evolutionary game theory) predict an efficient separating equilibrium, where the signal is sent in the infrequent state of the world (also referred to as Horn׳s rule). To analyze whether Horn׳s rule applies, and if so, which theory best explains it, we develop and test variants of the sender-receiver game where the theories generate discriminatory hypotheses. In costly signaling variants, our participants follow Horn׳s rule most of the time, in a manner that is best explained by focal point theory. In costless signaling variants, evolutionary game theory best explains our results. Here participants coordinate significantly more (less) often on a separating equilibrium where the signal is sent in the frequent state if they are primed to associate the absence of a signal with the infrequent (frequent) state of the world. We also find indications that a similar priming effect applies to costly signals. Thus, while the frequency with which participants follow Horn׳s rule in costly signaling variants is best explained by Horn׳s rule, the priming effect shows that some of our participants׳ behavior is best explained by evolutionary game theory even when signals are costly. Copyright © 2014 Elsevier Ltd. All rights reserved.

The Reactive-Causal Architecture: Introducing an Emotion Model along with Theories of Needs

NASA Astrophysics Data System (ADS)

Aydin, Ali Orhan; Orgun, Mehmet Ali

In the entertainment application area, one of the major aims is to develop believable agents. To achieve this aim, agents should be highly autonomous, situated, flexible, and display affect. The Reactive-Causal Architecture (ReCau) is proposed to simulate these core attributes. In its current form, ReCau cannot explain the effects of emotions on intelligent behaviour. This study aims is to further improve the emotion model of ReCau to explain the effects of emotions on intelligent behaviour. This improvement allows ReCau to be emotional to support the development of believable agents.

Home retrofitting for energy conservation and solar considerations

NASA Astrophysics Data System (ADS)

1981-10-01

A manual which explains both the key concepts behind the need for and the home energy efficiency improvement is reviewed. A comprehensive picture of how home energy use is effected by the inhabitants and by the structure itself is presented. The manual explains: looking at energy, how the heat transfer occurs between houses and humans, energy audits and how to use them, energy conservation actions to do now to reduce energy use. Schemes to reduce infiltration, how to increase insulation, and what to do with windows and doors, heating and heat distribution systems, and water heaters are included. Solar energy options are explained, as well as financing and tax credits.

Protection from childhood asthma and allergy in Alpine farm environments-the GABRIEL Advanced Studies.

PubMed

Illi, Sabina; Depner, Martin; Genuneit, Jon; Horak, Elisabeth; Loss, Georg; Strunz-Lehner, Christine; Büchele, Gisela; Boznanski, Andrzej; Danielewicz, Hanna; Cullinan, Paul; Heederik, Dick; Braun-Fahrländer, Charlotte; von Mutius, Erika

2012-06-01

Studies on the association of farm environments with asthma and atopy have repeatedly observed a protective effect of farming. However, no single specific farm-related exposure explaining this protective farm effect has consistently been identified. We sought to determine distinct farm exposures that account for the protective effect of farming on asthma and atopy. In rural regions of Austria, Germany, and Switzerland, 79,888 school-aged children answered a recruiting questionnaire (phase I). In phase II a stratified random subsample of 8,419 children answered a detailed questionnaire on farming environment. Blood samples and specific IgE levels were available for 7,682 of these children. A broad asthma definition was used, comprising symptoms, diagnosis, or treatment ever. Children living on a farm were at significantly reduced risk of asthma (adjusted odds ratio [aOR], 0.68; 95% CI, 0.59-0.78; P< .001), hay fever (aOR, 0.43; 95% CI, 0.36-0.52; P< .001), atopic dermatitis (aOR, 0.80; 95% CI, 0.69-0.93; P= .004), and atopic sensitization (aOR, 0.54; 95% CI, 0.48-0.61; P< .001) compared with nonfarm children. Whereas this overall farm effect could be explained by specific exposures to cows, straw, and farm milk for asthma and exposure to fodder storage rooms and manure for atopic dermatitis, the farm effect on hay fever and atopic sensitization could not be completely explained by the questionnaire items themselves or their diversity. A specific type of farm typical for traditional farming (ie, with cows and cultivation) was protective against asthma, hay fever, and atopy. However, whereas the farm effect on asthma could be explained by specific farm characteristics, there is a link still missing for hay fever and atopy. Copyright © 2012 American Academy of Allergy, Asthma & Immunology. Published by Mosby, Inc. All rights reserved.

The psychosocial experience of feeling overweight promotes increased snack food consumption in women but not men.

PubMed

Oldham, Melissa; Tomiyama, A Janet; Robinson, Eric

2018-06-05

Self-identification of being overweight has been associated with overeating and weight gain in observational studies, irrespective of whether the individual in question is objectively overweight. The aims of the present studies were to examine whether experimentally manipulating the psychosocial experience of feeling overweight impacted on snack food consumption and to identify mechanisms explaining this effect. In Study 1, to manipulate the psychosocial experience of feeling overweight, 120 women wore an obese body suit or control clothing in public or private settings, before consuming snack foods. Wearing the obese body suit resulted in an increase in snack food consumption and this effect was not moderated by whether participants wore the obese body suit in public or in private. In Study 2, we aimed to replicate the effect of the obese body suit on snack food consumption and also examined whether the effect of the body suit on eating behaviour was moderated by participant sex (n = 150; 80 women). Women who wore the obese body suit ate significantly more than women who wore the control clothing, but this effect was not observed in men. Across both studies we examined a number of potential mechanisms that could explain the effect that wearing the obese body suit had on snack food consumption, but did not find supporting evidence. The psychosocial experience of feeling overweight may lead to increased snack food consumption in women, but the psychological mechanism explaining this effect is unclear. Copyright © 2018. Published by Elsevier Ltd.

Undergraduate and Masters Students' Understanding about Properties of Air and the Forms of Reasoning Used to Explain Air Phenomena

ERIC Educational Resources Information Center

Bulunuz, Mizrap; Jarrett, Olga S.

2009-01-01

The purposes of this study were to examine initial content knowledge about properties of air by three cohorts of undergraduate and master's students studying elementary education and to determine forms of reasoning used to explain air phenomena and the effect of an intervention on content knowledge. Subjects were assessed using a 14-question test…

Insulation commonality assessment (phase 1). Volume 2: Section 7.0 through 16.0. [evaluation of materials used for spacecraft thermal insulation

NASA Technical Reports Server (NTRS)

1973-01-01

The heat transfer characteristics of various materials used for the thermal insulation of spacecraft are discussed. Techniques for conducting thermal performance analysis, structural performance analysis, and dynamic analysis are described. Processes for producing and finishing the materials are explained. The methods for determining reliability, system safety, materials tests, and design effectiveness are explained.

Do Differences in School's Instruction Time Explain International Achievement Gaps in Math, Science, and Reading? Evidence from Developed and Developing Countries. NBER Working Paper No. 16227

ERIC Educational Resources Information Center

Lavy, Victor

2010-01-01

There are large differences across countries in instructional time in schooling institutions. Can these differences explain some of the differences across countries in pupils' achievements in different subjects? While research in recent years provides convincing evidence about the effect of several inputs in the education production function,…

Can Research Design Explain Variation in Head Start Research Results? A Meta-Analysis of Cognitive and Achievement Outcomes

ERIC Educational Resources Information Center

Shager, Hilary M.; Schindler, Holly S.; Magnuson, Katherine A.; Duncan, Greg J.; Yoshikawa, Hirokazu; Hart, Cassandra M. D.

2013-01-01

This study explores the extent to which differences in research design explain variation in Head Start program impacts. We employ meta-analytic techniques to predict effect sizes for cognitive and achievement outcomes as a function of the type and rigor of research design, quality and type of outcome measure, activity level of control group, and…

Variation in fistula use across dialysis facilities: is it explained by case-mix?

PubMed

Tangri, Navdeep; Moorthi, Ranjani; Tighiouhart, Hocine; Meyer, Klemens B; Miskulin, Dana C

2010-02-01

Arteriovenous fistulas (AVFs) remain the preferred vascular access for hemodialysis patients. Dialysis facilities that fail to meet Centers for Medicare & Medicaid Services goals cite patient case-mix as a reason for low AVF prevalence. This study aimed to determine the magnitude of the variability in AVF usage across dialysis facilities and the extent to which patient case-mix explains it. The vascular access used in 10,112 patients dialyzed at 173 Dialysis Clinic Inc. facilities from October 1 to December 31, 2004, was evaluated. The access in use was considered to be an AVF if it was used for >70% of hemodialysis treatments. Mixed-effects models with a random intercept for dialysis facilities evaluated the effect of facilities on AVF usage. Sequentially adjusted multivariate models measured the extent to which patient factors (case-mix) explain variation across facilities in AVF rates. 3787 patients (38%) were dialyzed using AVFs. There was a significant facility effect: 7.6% of variation in AVF use was attributable to facility. This was reduced to 7.1% after case-mix adjustment. There were no identified specific facility-level factors that explained the interfacility variation. AVF usage varies across dialysis facilities, and patient case-mix did not reduce this variation. In this study, 92% of the total variation in AVF usage was due to patient factors, but most were not measurable. A combination of patient factors and process indicators should be considered in adjudicating facility performance for this quality indicator.

Gender differences in sickness absence--the contribution of occupation and workplace.

PubMed

Laaksonen, Mikko; Mastekaasa, Arne; Martikainen, Pekka; Rahkonen, Ossi; Piha, Kustaa; Lahelma, Eero

2010-09-01

The aim of this study was to examine whether differences in male and female occupations and workplaces explain gender differences in self-certified (1-3 days) and medically confirmed sickness absence episodes of various lengths (> or = 4 days, >2 weeks, >60 days). Analyses in the main ICD-10 diagnostic groups were conducted for absence episodes of >2 weeks. Furthermore, we examined whether the contribution of occupation is related to different distributions of female and male jobs across the social class hierarchy. All municipal employees of the City of Helsinki at the beginning of 2004 (N=36 395) were followed-up until the end of 2007. Conditional fixed-effects Poisson regression was used to control for differences between occupations and workplaces. Controlling for occupation accounted for half of the female excess in self-certified and medically confirmed episodes lasting >60 days. In the intermediate categories, this explained about one third of the female excess. The effect of workplace was similar but weaker. Occupational and workplace differences explained the female excess in sickness absence due to mental and behavioral disorders, musculoskeletal diseases, and respiratory diseases. The effect of occupation was clearly stronger than that of social class in self-certified absence episodes, whereas in medically confirmed sickness absence episodes gender differences were to a large extent related to social class differences between occupations. Differences between occupations held by women and men explain a substantial part of the female excess in sickness absence. Mental and behavioral disorders and musculoskeletal diseases substantially contribute to this explanation.

Neighbourhood and own social housing and early problem behaviour trajectories.

PubMed

Flouri, Eirini; Midouhas, Emily; Tzatzaki, Konstantina

2015-02-01

To explore the roles of proportion of social rented housing in the neighbourhood ('neighbourhood social housing'), own housing being socially rented, and their interaction in early trajectories of emotional, conduct and hyperactivity symptoms. We tested three pathways of effects: family stress and maternal psychological distress, low quality parenting practices, and peer problems. We used data from 9,850 Millennium Cohort Study families who lived in England when the cohort children were aged 3. Children's emotional, conduct and hyperactivity problems were measured at ages 3, 5 and 7. Even after accounting for own social housing, neighbourhood social housing was related to all problems and their trajectories. Its association with conduct problems and hyperactivity was explained by selection. Selection also explained the effect of the interaction between neighbourhood and own social housing on hyperactivity, but not why children of social renter families living in neighbourhoods with lower concentrations of social housing followed a rising trajectory of emotional problems. The effects of own social housing, neighbourhood social housing and their interaction on emotional problems were robust. Peer problems explained the association of own social housing with hyperactivity. Neither selection nor the pathways we tested explained the association of own social housing with conduct problems, the association of neighbourhood social housing with their growth, or the association of neighbourhood social housing, own social housing and their interaction with emotional problems. Children of social renter families in neighbourhoods with a low concentration of social renters are particularly vulnerable to emotional problems.

Alcohol expectancies longitudinally predict drinking and the alcohol myopia effects of relief, self-inflation, and excess.

PubMed

Lac, Andrew; Brack, Nathaniel

2018-02-01

Alcohol myopia theory posits that alcohol consumption attenuates information processing capacity, and that expectancy beliefs together with intake level are responsible for experiences in myopic effects (relief, self-inflation, and excess). Adults (N=413) averaging 36.39 (SD=13.02) years of age completed the Comprehensive Effects of Alcohol questionnaire at baseline, followed by alcohol use measures (frequency and quantity) and the Alcohol Myopia Scale one month later. Three structural equation models based on differing construct manifestations of alcohol expectancies served to longitudinally forecast alcohol use and myopia. In Model 1, overall expectancy predicted greater alcohol use and higher levels of all three myopic effects. In Model 2, specifying separate positive and negative expectancy factors, positive but not negative expectancy predicted greater use. Furthermore, positive expectancy and use explained higher myopic relief and higher self-inflation, whereas positive expectancy, negative expectancy, and use explained higher myopic excess. In Model 3, the seven specific expectancy subscales (sociability, tension reduction, liquid courage, sexuality, cognitive and behavioral impairment, risk and aggression, and self-perception) were simultaneously specified as predictors. Tension reduction expectancy, sexuality expectancy, and use contributed to higher myopic relief; sexuality expectancy and use explained higher myopic self-inflation; and risk and aggression expectancy and use accounted for higher myopic excess. Across all three predictive models, the total variance explained ranged from 12 to 19% for alcohol use, 50 to 51% for relief, 29 to 34% for self-inflation, and 32 to 35% for excess. Findings support that the type of alcohol myopia experienced is a concurrent function of self-fulfilling alcohol prophecies and drinking levels. The interpreted measurement manifestation of expectancy yielded different prevention implications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Alcohol, wine and platelet function.

PubMed

Ruf, Jean-Claude

2004-01-01

Epidemiological studies have demonstrated an inverse correlation between moderate wine and alcohol consumption and morbidity and mortality from coronary heart disease. The protective effect has been associated with an increase in the plasma level of HDL cholesterol, as it is well recognized that plasma HDL is inversely correlated with CHD. In addition, it has become evident that blood platelets contribute to the rate of development of atherosclerosis and CHD through several mechanisms. In recent studies it has been shown that the level of HDL cholesterol can explain only 50% of the protective effect of alcoholic beverages; the other 50% may be partly related to a decrease in platelet activity. This anti-platelet activity of wine is explained by ethanol but also by the polyphenolic components with which red wines are richly endowed. Several studies carried out on humans and animals have shown that wine phenolics could exert their effects by reducing prostanoid synthesis from arachidonate. In addition, it has been suggested that wine phenolics could reduce platelet activity mediated by nitric oxide. Moreover, wine phenolics increase vitamin E levels while decreasing the oxidation of platelets submitted to oxidative stress. However, a rebound phenomenon of hyperaggregability is observed after an acute alcohol consumption which is not observed with wine consumption. This protection afforded by wine has been duplicated in animals with grape phenolics added to alcohol. The rebound phenomenon may explain ischemic strokes or sudden deaths known to occur after episodes of drunkenness. It appears that wine, and wine phenolics in particular, could have a more significant inhibitory effect on platelet aggregation and could explain, in part, the hypothesis that red wine is more protective against atherosclerosis and coronary heart disease.

Chiral pair of Fermi arcs, anomaly cancellation, and spin or valley Hall effects in Weyl metals with broken inversion symmetry

NASA Astrophysics Data System (ADS)

Jang, Iksu; Kim, Ki-Seok

2018-04-01

Anomaly cancellation has been shown to occur in broken time-reversal symmetry Weyl metals, which explains the existence of a Fermi arc. We extend this result in the case of broken inversion symmetry Weyl metals. Constructing a minimal model that takes a double pair of Weyl points, we demonstrate the anomaly cancellation explicitly. This demonstration explains why a chiral pair of Fermi arcs appear in broken inversion symmetry Weyl metals. In particular, we find that this pair of Fermi arcs gives rise to either "quantized" spin Hall or valley Hall effects, which corresponds to the "quantized" version of the charge Hall effect in broken time-reversal symmetry Weyl metals.

The weapons effect.

PubMed

Benjamin, Arlin James; Bushman, Brad J

2018-02-01

In some societies, weapons are plentiful and highly visible. This review examines recent trends in research on the weapons effect, which is the finding that the mere presence of weapons can prime people to behave aggressively. The General Aggression Model provides a theoretical framework to explain why the weapons effect occurs. This model postulates that exposure to weapons increases aggressive thoughts and hostile appraisals, thus explaining why weapons facilitate aggressive behavior. Data from meta-analytic reviews are consistent with the General Aggression Model. These findings have important practical as well as theoretical implications. They suggest that the link between weapons and aggression is very strong in semantic memory, and that merely seeing a weapon can make people more aggressive. Copyright © 2017 Elsevier Ltd. All rights reserved.

How much of the income inequality effect can be explained by public policy? Evidence from oral health in Brazil.

PubMed

Celeste, Roger Keller; Nadanovsky, Paulo

2010-10-01

To evaluate the association between income inequality, a public policy scale and to oral health. Analysis, using the Brazilian oral health survey in 2002-2003, included 23,573 15-19-year-old subjects clustered in 330 municipalities. Missing and decayed teeth and malocclusion assessments were the outcomes. Gini coefficient and a novel Scale of Municipal Public Policies were the main exposure variables. Individual level covariates were used as controls in multilevel regressions. An increase from the lowest to the highest Gini value in Brazil was associated with an increase in the number of missing (rate ratio, RR=2.11 confidence interval 95% 1.18-3.77) and decayed teeth (RR=2.92 CI 95% 1.83-4.65). After adjustment for public policies and water fluoridation, the Gini effect was non-significant and public policies explained most of the variation in missing and decayed teeth. The public policy scale remained significant after adjustment with a rate ratio of 0.64 for missing and 0.72 for decayed teeth. Neither Gini nor public policies were significantly related to malocclusion. The public policy effect on missing and decayed teeth was stronger among those with higher education and income. Income inequality effect was explained mainly by public policies, which had an independent effect that was greater among the better-off. Copyright (c) 2010 Elsevier Ireland Ltd. All rights reserved.

Interactions and Toxicity of Cu-Zn mixtures to Hordeum vulgare in Different Soils Can Be Rationalized with Bioavailability-Based Prediction Models.

PubMed

Qiu, Hao; Versieren, Liske; Rangel, Georgina Guzman; Smolders, Erik

2016-01-19

Soil contamination with copper (Cu) is often associated with zinc (Zn), and the biological response to such mixed contamination is complex. Here, we investigated Cu and Zn mixture toxicity to Hordeum vulgare in three different soils, the premise being that the observed interactions are mainly due to effects on bioavailability. The toxic effect of Cu and Zn mixtures on seedling root elongation was more than additive (i.e., synergism) in soils with high and medium cation-exchange capacity (CEC) but less than additive (antagonism) in a low-CEC soil. This was found when we expressed the dose as the conventional total soil concentration. In contrast, antagonism was found in all soils when we expressed the dose as free-ion activities in soil solution, indicating that there is metal-ion competition for binding to the plant roots. Neither a concentration addition nor an independent action model explained mixture effects, irrespective of the dose expressions. In contrast, a multimetal BLM model and a WHAM-Ftox model successfully explained the mixture effects across all soils and showed that bioavailability factors mainly explain the interactions in soils. The WHAM-Ftox model is a promising tool for the risk assessment of mixed-metal contamination in soils.

Type 2 diabetes, but not obesity, prevalence is positively associated with ambient temperature.

PubMed

Speakman, John R; Heidari-Bakavoli, Sahar

2016-08-01

Cold exposure stimulates energy expenditure and glucose disposal. If these factors play a significant role in whole body energy balance, and glucose homeostasis, it is predicted that both obesity and type 2 diabetes prevalence would be lower where it is colder. Previous studies have noted connections between ambient temperature and obesity, but the direction of the effect is confused. No previous studies have explored the link of type 2 diabetes to ambient temperature. We used county level data for obesity and diabetes prevalence across the mainland USA and matched this to county level ambient temperature data. Average ambient temperature explained 5.7% of the spatial variation in obesity and 29.6% of the spatial variation in type 2 diabetes prevalence. Correcting the type 2 diabetes data for the effect of obesity reduced the explained variation to 26.8%. Even when correcting for obesity, poverty and race, ambient temperature explained 12.4% of the variation in the prevalence of type 2 diabetes, and this significant effect remained when latitude was entered into the model as a predictor. When obesity prevalence was corrected for poverty and race the significant effect of temperature disappeared. Enhancing energy expenditure by cold exposure will likely not impact obesity significantly, but may be useful to combat type 2 diabetes.

The association between physical activity and eating self-regulation in overweight and obese women.

PubMed

Carraça, Eliana V; Silva, Marlene N; Coutinho, Sílvia R; Vieira, Paulo N; Minderico, Cláudia S; Sardinha, Luís B; Teixeira, Pedro J

2013-01-01

Successful weight management relies heavily on eating and exercise behaviors. However, little is known about the association between both on a psychosocial level. This study examined the relationship between exercise and eating regulation by exploring the mediating effects of negative body image investment and depressive mood, and their stability through time. Analyses were conducted at two different moments (12 and 36 months), involving a sample of 221 overweight/obese women (age: 37.6 ± 7 years; BMI: 31.6 ± 4.1 kg/m(2)) that participated in a behavioral weight control intervention. Bivariate correlations and mediation analyses using Preacher & Hayes resampling procedures were conducted. At 12 months, negative body image investment was the only significant mediator of the exercise-eating relationship. This variable explained larger portions of the indirect effects of structured rather than lifestyle exercise on eating. At 36 months, negative investment and to a lesser extent depressive mood partially explained the exercise-eating association. Our findings suggest that, besides physiological effects of exercise, psychological mechanisms related to body image and mood also explain the role of physical activity as a 'gateway behavior' for improved eating regulation in overweight women. These effects appear to be stable and may help understand the key role of exercise in long-term weight management.

Climate change: believing and seeing implies adapting.

PubMed

Blennow, Kristina; Persson, Johannes; Tomé, Margarida; Hanewinkel, Marc

2012-01-01

Knowledge of factors that trigger human response to climate change is crucial for effective climate change policy communication. Climate change has been claimed to have low salience as a risk issue because it cannot be directly experienced. Still, personal factors such as strength of belief in local effects of climate change have been shown to correlate strongly with responses to climate change and there is a growing literature on the hypothesis that personal experience of climate change (and/or its effects) explains responses to climate change. Here we provide, using survey data from 845 private forest owners operating in a wide range of bio-climatic as well as economic-social-political structures in a latitudinal gradient across Europe, the first evidence that the personal strength of belief and perception of local effects of climate change, highly significantly explain human responses to climate change. A logistic regression model was fitted to the two variables, estimating expected probabilities ranging from 0.07 (SD ± 0.01) to 0.81 (SD ± 0.03) for self-reported adaptive measures taken. Adding socio-demographic variables improved the fit, estimating expected probabilities ranging from 0.022 (SD ± 0.008) to 0.91 (SD ± 0.02). We conclude that to explain and predict adaptation to climate change, the combination of personal experience and belief must be considered.

Leader dark traits, workplace bullying, and employee depression: Exploring mediation and the role of the dark core.

PubMed

Tokarev, Alexander; Phillips, Abigail R; Hughes, David J; Irwing, Paul

2017-10-01

A growing body of empirical evidence now supports a negative association between dark traits in leaders and the psychological health of employees. To date, such investigations have mostly focused on psychopathy, nonspecific measures of psychological wellbeing, and have not considered the mechanisms through which these relationships might operate. In the current study (N = 508), we utilized other-ratings of personality (employees rated leaders' personality), psychometrically robust measures, and sophisticated modeling techniques, to examine whether the effects of leaders' levels of narcissism and psychopathy on employee depression are mediated by workplace bullying. Structural equation models provided clear evidence to suggest that employee perceptions of both leader narcissism and psychopathy are associated with increased workplace bullying (25.8% and 41.0% variance explained, respectively) and that workplace bullying fully mediates the effect of leader narcissism and psychopathy on employee depression (21.5% and 20.8% variance explained, respectively). However, when psychopathy and narcissism were modeled concurrently, narcissism did not explain any variance in bullying, suggesting that it is the overlap between psychopathy and narcissism, namely, the "dark core," which primarily accounts for the observed effects. We examined this assertion empirically and explored the unique effects of the subfactors of psychopathy. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Why Income Comparison is Rational

NASA Technical Reports Server (NTRS)

Wolpert, David H.

2010-01-01

A major factor affecting a person s happiness is the gap between their income and their neighbors , independent of their own income. This effect is strongest when the neighbor has moderately higher income. In addition a person s lifetime happiness often follows a "U" shape. Previous models have explained subsets of these phenomena, typically assuming the person has limited ability to assess their own (hedonic) utility. Here I present a model that explains all the phenomena, without such assumptions. In this model greater income of your neighbor is statistical data that, if carefully analyzed, would recommend that you explore for a new income-generating strategy. This explains unhappiness that your neighbor has greater income, as an emotional "prod" that induces you to explore, in accord with careful statistical analysis. It explains the "U" shape of happiness similarly. Another benefit of this model is that it makes many falsifiable predictions.

The role of research-article writing motivation and self-regulatory strategies in explaining research-article abstract writing ability.

PubMed

Lin, Ming-Chia; Cheng, Yuh-Show; Lin, Sieh-Hwa; Hsieh, Pei-Jung

2015-04-01

The purpose of the study was to investigate the effects of research-article writing motivation and use of self-regulatory writing strategies in explaining second language (L2) research-article abstract writing ability, alongside the L2 literacy effect. Four measures were administered: a L2 literacy test, a research abstract performance assessment, and inventories of writing motivation and strategy. Participants were L2 graduate students in Taiwan (N=185; M age=25.8 yr., SD=4.5, range=22-53). Results of structural equation modeling showed a direct effect of motivation on research-article writing ability, but no direct effect of strategy or indirect effect of motivation via strategy on research-article writing ability, with L2 literacy controlled. The findings suggest research-article writing instruction should address writing motivation, besides L2 literacy.

Ferromagnetic bond of Li{sub 10} cluster: An alternative approach in terms of effective ferromagnetic sites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donoso, Roberto; Fuentealba, Patricio, E-mail: pfuentea@hotmail.es, E-mail: cardena@macul.ciencias.uchile.cl; Cárdenas, Carlos, E-mail: pfuentea@hotmail.es, E-mail: cardena@macul.ciencias.uchile.cl

In this work, a model to explain the unusual stability of atomic lithium clusters in their highest spin multiplicity is presented and used to describe the ferromagnetic bonding of high-spin Li{sub 10} and Li{sub 8} clusters. The model associates the (lack of-)fitness of Heisenberg Hamiltonian with the degree of (de-)localization of the valence electrons in the cluster. It is shown that a regular Heisenberg Hamiltonian with four coupling constants cannot fully explain the energy of the different spin states. However, a more simple model in which electrons are located not at the position of the nuclei but at the positionmore » of the attractors of the electron localization function succeeds in explaining the energy spectrum and, at the same time, explains the ferromagnetic bond found by Shaik using arguments of valence bond theory. In this way, two different points of view, one more often used in physics, the Heisenberg model, and the other in chemistry, valence bond, come to the same answer to explain those atypical bonds.« less

Robust estimation of the proportion of treatment effect explained by surrogate marker information.

PubMed

Parast, Layla; McDermott, Mary M; Tian, Lu

2016-05-10

In randomized treatment studies where the primary outcome requires long follow-up of patients and/or expensive or invasive obtainment procedures, the availability of a surrogate marker that could be used to estimate the treatment effect and could potentially be observed earlier than the primary outcome would allow researchers to make conclusions regarding the treatment effect with less required follow-up time and resources. The Prentice criterion for a valid surrogate marker requires that a test for treatment effect on the surrogate marker also be a valid test for treatment effect on the primary outcome of interest. Based on this criterion, methods have been developed to define and estimate the proportion of treatment effect on the primary outcome that is explained by the treatment effect on the surrogate marker. These methods aim to identify useful statistical surrogates that capture a large proportion of the treatment effect. However, current methods to estimate this proportion usually require restrictive model assumptions that may not hold in practice and thus may lead to biased estimates of this quantity. In this paper, we propose a nonparametric procedure to estimate the proportion of treatment effect on the primary outcome that is explained by the treatment effect on a potential surrogate marker and extend this procedure to a setting with multiple surrogate markers. We compare our approach with previously proposed model-based approaches and propose a variance estimation procedure based on a perturbation-resampling method. Simulation studies demonstrate that the procedure performs well in finite samples and outperforms model-based procedures when the specified models are not correct. We illustrate our proposed procedure using a data set from a randomized study investigating a group-mediated cognitive behavioral intervention for peripheral artery disease participants. Copyright © 2015 John Wiley & Sons, Ltd.

The Common Sense of Small Nuclear Arsenals

DTIC Science & Technology

2012-01-01

affairs. That pattern is continuing and, therefore, is worth examining. In this article I use structural theory to explain what I call “the com­ mon...deterrence and dis­ suasion and then explain small nuclear arsenals in terms of structural theory , relying most heavily on the effects of socialization...deterrence are particularly useful. Dissuasion and general deterrence share many common elements. Both are rooted in deterrence theory and share an

Comorbid psychopathology and stress mediate the relationship between autistic traits and repetitive behaviours in adults with autism.

PubMed

García-Villamisar, D; Rojahn, J

2015-02-01

Comorbid psychopathology and stress were considered possible mediators that may explain the relationship between some autistic traits and repetitive behaviours. The current study sought to examine the mediational effects of comorbid psychopathology, executive dysfunctions and stress in the relationship between some autistic traits and repetitive behaviours. A battery of questionnaires including measures of autistic traits, repetitive behaviours, stress, executive dysfunctions and comorbid psychopathology were administered to a sample of adults with autism and intellectual disabilities (n = 43). We found that when taken as set dimensions of comorbidity, dysexecutive functioning and stress mediated or explained the effects of autistic symptoms on repetitive behaviour. The total model explained 60% of the variation in repetitive behaviours (R = 0.60; F = 13.64, P < 0.001). The results are discussed in the light of pertinent previous research and their clinical implications, and suggestions for future research are provided. According to the investigated model, increased levels of comorbid psychopathology and stress explained the relationships between repetitive/restrictive behaviours and autistic traits in adults with autism, while executive functioning did not contribute to that relationship. © 2013 2013 MENCAP and International Association of the Scientific Study of Intellectual and Developmental Disabilities and John Wiley & Sons Ltd.

Probability theory plus noise: Replies to Crupi and Tentori (2016) and to Nilsson, Juslin, and Winman (2016).

PubMed

Costello, Fintan; Watts, Paul

2016-01-01

A standard assumption in much of current psychology is that people do not reason about probability using the rules of probability theory but instead use various heuristics or "rules of thumb," which can produce systematic reasoning biases. In Costello and Watts (2014), we showed that a number of these biases can be explained by a model where people reason according to probability theory but are subject to random noise. More importantly, that model also predicted agreement with probability theory for certain expressions that cancel the effects of random noise: Experimental results strongly confirmed this prediction, showing that probabilistic reasoning is simultaneously systematically biased and "surprisingly rational." In their commentaries on that paper, both Crupi and Tentori (2016) and Nilsson, Juslin, and Winman (2016) point to various experimental results that, they suggest, our model cannot explain. In this reply, we show that our probability theory plus noise model can in fact explain every one of the results identified by these authors. This gives a degree of additional support to the view that people's probability judgments embody the rational rules of probability theory and that biases in those judgments can be explained as simply effects of random noise. (c) 2015 APA, all rights reserved).

Piezoelectric Ceramics and Their Applications

ERIC Educational Resources Information Center

Flinn, I.

1975-01-01

Describes the piezoelectric effect in ceramics and presents a quantitative representation of this effect. Explains the processes involved in the manufacture of piezoelectric ceramics, the materials used, and the situations in which they are applied. (GS)

Multi Vitamin E: E-lusive E-ffects

PubMed Central

2015-01-01

Investigations into vitamin E’s anti-inflammatory effects must be more comprehensive: Dr Joan Cook-Mills explains how their research could redefine medical perceptions and shed new light on previous studies PMID:27175228

The Source of the Symbolic Numerical Distance and Size Effects

PubMed Central

Krajcsi, Attila; Lengyel, Gábor; Kojouharova, Petia

2016-01-01

Human number understanding is thought to rely on the analog number system (ANS), working according to Weber’s law. We propose an alternative account, suggesting that symbolic mathematical knowledge is based on a discrete semantic system (DSS), a representation that stores values in a semantic network, similar to the mental lexicon or to a conceptual network. Here, focusing on the phenomena of numerical distance and size effects in comparison tasks, first we discuss how a DSS model could explain these numerical effects. Second, we demonstrate that the DSS model can give quantitatively as appropriate a description of the effects as the ANS model. Finally, we show that symbolic numerical size effect is mainly influenced by the frequency of the symbols, and not by the ratios of their values. This last result suggests that numerical distance and size effects cannot be caused by the ANS, while the DSS model might be the alternative approach that can explain the frequency-based size effect. PMID:27917139

Sibship size and educational attainment. A joint test of the Confluence Model and the Resource Dilution Hypothesis

PubMed Central

Jæger, Mads Meier

2012-01-01

Studies on family background often explain the negative effect of sibship size on educational attainment by one of two theories: the Confluence Model (CM) or the Resource Dilution Hypothesis (RDH). However, as both theories – for substantively different reasons – predict that sibship size should have a negative effect on educational attainment most studies cannot distinguish empirically between the CM and the RDH. In this paper, I use the different theoretical predictions in the CM and RDH on the role of cognitive ability as a partial or complete mediator of the effect of sibship size to distinguish the two theories and to identify a unique RDH effect on educational attainment. Using sibling data from the Wisconsin Longitudinal Study (WLS) and a random effect Instrumental Variable model I find that, in addition to a negative effect on cognitive ability, sibship size also has a strong negative effect on educational attainment which is uniquely explained by the RDH. PMID:22468016

Visual attention: The past 25 years

PubMed Central

Carrasco, Marisa

2012-01-01

This review focuses on covert attention and how it alters early vision. I explain why attention is considered a selective process, the constructs of covert attention, spatial endogenous and exogenous attention, and feature-based attention. I explain how in the last 25 years research on attention has characterized the effects of covert attention on spatial filters and how attention influences the selection of stimuli of interest. This review includes the effects of spatial attention on discriminability and appearance in tasks mediated by contrast sensitivity and spatial resolution; the effects of feature-based attention on basic visual processes, and a comparison of the effects of spatial and feature-based attention. The emphasis of this review is on psychophysical studies, but relevant electrophysiological and neuroimaging studies and models regarding how and where neuronal responses are modulated are also discussed. PMID:21549742

The Prevention of Child Maltreatment Through the Nurse Family Partnership Program: Mediating Effects in a Long-Term Follow-Up Study.

PubMed

Eckenrode, John; Campa, Mary I; Morris, Pamela A; Henderson, Charles R; Bolger, Kerry E; Kitzman, Harriet; Olds, David L

2017-05-01

We examine maternal life-course mediators of the impact of a nurse home visitation program on reducing child maltreatment among participants in the Elmira trial of the Nurse Family Partnership program from the first child's birth through age 15. For women having experienced low to moderate levels of domestic violence, program effects on the number of confirmed maltreatment reports were mediated by reductions in numbers of subsequent children born to mothers and their reported use of public assistance. Together, the two mediators explained nearly one half of the total effect of nurse home visiting on child maltreatment. The long-term success of this program on reducing child maltreatment can be explained, at least in part, by its positive effect on pregnancy planning and economic self-sufficiency.

Visual attention: the past 25 years.

PubMed

Carrasco, Marisa

2011-07-01

This review focuses on covert attention and how it alters early vision. I explain why attention is considered a selective process, the constructs of covert attention, spatial endogenous and exogenous attention, and feature-based attention. I explain how in the last 25 years research on attention has characterized the effects of covert attention on spatial filters and how attention influences the selection of stimuli of interest. This review includes the effects of spatial attention on discriminability and appearance in tasks mediated by contrast sensitivity and spatial resolution; the effects of feature-based attention on basic visual processes, and a comparison of the effects of spatial and feature-based attention. The emphasis of this review is on psychophysical studies, but relevant electrophysiological and neuroimaging studies and models regarding how and where neuronal responses are modulated are also discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Lorentz Invariance Violation effects on UHECR propagation: A geometrized approach

NASA Astrophysics Data System (ADS)

Torri, Marco Danilo Claudio; Bertini, Stefano; Giammarchi, Marco; Miramonti, Lino

2018-06-01

We explore the possibility to geometrize the interaction of massive fermions with the quantum structure of space-time, trying to create a theoretical background, in order to explain what some recent experimental results seem to implicate on the propagation of Ultra High Energy Cosmic Rays (UHECR). We will investigate part of the phenomenological implications of this approach on the predicted effect of the UHECR suppression, in fact recent evidences seem to involve the modification of the GZK cut-off phenomenon. The search for an effective theory, which can explain this physical effect, is based on Lorentz Invariance Violation (LIV), which is introduced via Modified Dispersion Relations (MDRs). Furthermore we illustrate that this perspective implies a more general geometry of space-time than the usual Riemannian one, indicating, for example, the opportunity to resort to Finsler theory.

Species diversity and chemical properties of litter influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling

PubMed Central

Mao, Bing; Mao, Rong; Zeng, De-Hui

2017-01-01

Decomposition of litter mixtures generally cannot be predicted from the component species incubated in isolation. Therefore, such non-additive effects of litter mixing on soil C and N dynamics remain poorly understood in terrestrial ecosystems. In this study, litters of Mongolian pine and three dominant understory species and soil were collected from a Mongolian pine plantation in Northeast China. In order to examine the effects of mixed-species litter on soil microbial biomass N, soil net N mineralization and soil respiration, four single litter species and their mixtures consisting of all possible 2-, 3- and 4-species combinations were added to soils, respectively. In most instances, species mixing produced synergistic non-additive effects on soil microbial biomass N and soil respiration, but antagonistic non-additive effects on net N mineralization. Species composition rather than species richness explained the non-additive effects of species mixing on soil microbial biomass N and net N mineralization, due to the interspecific differences in litter chemical composition. Both litter species composition and richness explained non-additive soil respiration responses to mixed-species litter, while litter chemical diversity and chemical composition did not. Our study indicated that litter mixtures promoted soil microbial biomass N and soil respiration, and inhibited net N mineralization. Soil N related processes rather than soil respiration were partly explained by litter chemical composition and chemical diversity, highlighting the importance of functional diversity of litter on soil N cycling. PMID:28686660

Species diversity and chemical properties of litter influence non-additive effects of litter mixtures on soil carbon and nitrogen cycling.

PubMed

Mao, Bing; Mao, Rong; Zeng, De-Hui

2017-01-01

Decomposition of litter mixtures generally cannot be predicted from the component species incubated in isolation. Therefore, such non-additive effects of litter mixing on soil C and N dynamics remain poorly understood in terrestrial ecosystems. In this study, litters of Mongolian pine and three dominant understory species and soil were collected from a Mongolian pine plantation in Northeast China. In order to examine the effects of mixed-species litter on soil microbial biomass N, soil net N mineralization and soil respiration, four single litter species and their mixtures consisting of all possible 2-, 3- and 4-species combinations were added to soils, respectively. In most instances, species mixing produced synergistic non-additive effects on soil microbial biomass N and soil respiration, but antagonistic non-additive effects on net N mineralization. Species composition rather than species richness explained the non-additive effects of species mixing on soil microbial biomass N and net N mineralization, due to the interspecific differences in litter chemical composition. Both litter species composition and richness explained non-additive soil respiration responses to mixed-species litter, while litter chemical diversity and chemical composition did not. Our study indicated that litter mixtures promoted soil microbial biomass N and soil respiration, and inhibited net N mineralization. Soil N related processes rather than soil respiration were partly explained by litter chemical composition and chemical diversity, highlighting the importance of functional diversity of litter on soil N cycling.

Ecological effects of aphid abundance, genotypic variation, and contemporary evolution on plants.

PubMed

Turley, Nash E; Johnson, Marc T J

2015-07-01

Genetic variation and contemporary evolution within populations can shape the strength and nature of species interactions, but the relative importance of these forces compared to other ecological factors is unclear. We conducted a field experiment testing the effects of genotypic variation, abundance, and presence/absence of green peach aphids (Myzus persicae) on the growth, leaf nitrogen, and carbon of two plant species (Brassica napus and Solanum nigrum). Aphid genotype affected B. napus but not S. nigrum biomass explaining 20 and 7% of the total variation, respectively. Averaging across both plant species, the presence/absence of aphids had a 1.6× larger effect size (Cohen's d) than aphid genotype, and aphid abundance had the strongest negative effects on plant biomass explaining 29% of the total variation. On B. napus, aphid genotypes had different effects on leaf nitrogen depending on their abundance. Aphids did not influence leaf nitrogen in S. nigrum nor leaf carbon in either species. We conducted a second experiment in the field to test whether contemporary evolution could affect plant performance. Aphid populations evolved in as little as five generations, but the rate and direction of this evolution did not consistently vary between plant species. On one host species (B. napus), faster evolving populations had greater negative effects on host plant biomass, with aphid evolutionary rate explaining 23% of the variation in host plant biomass. Together, these results show that genetic variation and evolution in an insect herbivore can play important roles in shaping host plant ecology.

Diverging temperature responses of CO2 assimilation and plant development explain the overall effect of temperature on biomass accumulation in wheat leaves and grains

PubMed Central

Lohraseb, Iman; Collins, Nicholas C.

2017-01-01

Abstract There is a growing consensus in the literature that rising temperatures influence the rates of biomass accumulation by shortening the development of plant organs and the whole plant and by altering the rates of respiration and photosynthesis. A model describing the net effects of these processes on biomass would be useful, but would need to reconcile reported differences in the effects of night and day temperature on plant productivity. In this study, the working hypothesis was that the temperature responses of CO2 assimilation and plant development rates were divergent, and that their net effects could explain observed differences in biomass accumulation. In wheat (Triticum aestivum) plants, we followed the temperature responses of photosynthesis, respiration and leaf elongation, and confirmed that their responses diverged. We measured the amount of carbon assimilated per ‘unit of plant development’ in each scenario and compared it to the biomass that accumulated in growing leaves and grains. Our results suggested that, up to a temperature optimum, the rate of any developmental process increased with temperature more rapidly than that of CO2 assimilation and that this discrepancy, summarised by the CO2 assimilation rate per unit of plant development, could explain the observed reductions in biomass accumulation in plant organs under high temperatures. The model described the effects of night and day temperature equally well, and offers a simple framework for describing the effects of temperature on plant growth. PMID:28069595

Inter-individual Differences in the Effects of Aircraft Noise on Sleep Fragmentation

PubMed Central

McGuire, Sarah; Müller, Uwe; Elmenhorst, Eva-Maria; Basner, Mathias

2016-01-01

Study Objectives: Environmental noise exposure disturbs sleep and impairs recuperation, and may contribute to the increased risk for (cardiovascular) disease. Noise policy and regulation are usually based on average responses despite potentially large inter-individual differences in the effects of traffic noise on sleep. In this analysis, we investigated what percentage of the total variance in noise-induced awakening reactions can be explained by stable inter-individual differences. Methods: We investigated 69 healthy subjects polysomnographically (mean ± standard deviation 40 ± 13 years, range 18–68 years, 32 male) in this randomized, balanced, double-blind, repeated measures laboratory study. This study included one adaptation night, 9 nights with exposure to 40, 80, or 120 road, rail, and/or air traffic noise events (including one noise-free control night), and one recovery night. Results: Mixed-effects models of variance controlling for reaction probability in noise-free control nights, age, sex, number of noise events, and study night showed that 40.5% of the total variance in awakening probability and 52.0% of the total variance in EEG arousal probability were explained by inter-individual differences. If the data set was restricted to nights (4 exposure nights with 80 noise events per night), 46.7% of the total variance in awakening probability and 57.9% of the total variance in EEG arousal probability were explained by inter-individual differences. The results thus demonstrate that, even in this relatively homogeneous, healthy, adult study population, a considerable amount of the variance observed in noise-induced sleep disturbance can be explained by inter-individual differences that cannot be explained by age, gender, or specific study design aspects. Conclusions: It will be important to identify those at higher risk for noise induced sleep disturbance. Furthermore, the custom to base noise policy and legislation on average responses should be re-assessed based on these findings. Citation: McGuire S, Müller U, Elmenhorst EM, Basner M. Inter-individual differences in the effects of aircraft noise on sleep fragmentation. SLEEP 2016;39(5):1107–1110. PMID:26856901

Interactions between psychosocial and built environment factors in explaining older adults' physical activity.

PubMed

Carlson, Jordan A; Sallis, James F; Conway, Terry L; Saelens, Brian E; Frank, Lawrence D; Kerr, Jacqueline; Cain, Kelli L; King, Abby C

2012-01-01

To evaluate ecological model predictions of cross-level interactions among psychosocial and environmental correlates of physical activity in 719 community-dwelling older adults in the Baltimore, Maryland and Seattle, Washington areas during 2005-2008. Walkability, access to parks and recreation facilities and moderate-to-vigorous physical activity (MVPA) minutes per week (min/week) were measured objectively. Neighborhood aesthetics, walking facilities, social support, self-efficacy, barriers and transportation and leisure walking min/week were self-reported. Walkability interacted with social support in explaining total MVPA (B=13.71) and with social support (B=7.90), self-efficacy (B=7.66) and barriers (B=-8.26) in explaining walking for transportation. Aesthetics interacted with barriers in explaining total MVPA (B=-12.20) and walking facilities interacted with self-efficacy in explaining walking for leisure (B=-10.88; Ps<.05). Summarizing across the interactions, living in a supportive environment (vs. unsupportive) was related to 30-59 more min/week of physical activity for participants with more positive psychosocial attributes, but only 0-28 more min/week for participants with less positive psychosocial attributes. Results supported synergistic interactions between built environment and psychosocial factors in explaining physical activity among older adults. Findings suggest multilevel interventions may be most effective in increasing physical activity. Copyright © 2011 Elsevier Inc. All rights reserved.

Associations of Body Mass Index, Motor Performance, and Perceived Athletic Competence with Physical Activity in Normal Weight and Overweight Children

PubMed Central

Cairney, John; Eisenmann, Joe; Pfeiffer, Karin; Gould, Dan

2018-01-01

Children who are overweight and obese display lower physical activity levels than normal weight peers. Measures of weight status, perceived motor competence, and motor skill performance have been identified as potential correlates explaining this discrepancy. 1881 children (955 males; 926 females; 9.9 years) were assessed as part of the Physical Health Activity Study Team project. The age, habitual physical activity participation (PAP), body mass index (BMI), socioeconomic status (SES), motor performance (MP), and perceived athletic competence (PAC) of each child included were assessed. Gender-specific linear regression analyses (main effects model) were conducted to identify the percent variance in PAP explained by the following variables: BMI, MP, and PAC. For males, 18.3% of the variance in PAP was explained by BMI, MP, and PAC. PAC explained 17% of the variance, while MP, BMI, and SES only accounted for 0.6%, 0.7%, and 0.5%, respectively. PAC explained 17.5% of PAP variance in females; MP explained 0.8%. BMI, SES, and chronological age were not significant correlates of PAP in girls. An established repertoire of motor skill performance has been seen as a vehicle to PAP in children; however, this study indicates that PAC should not be overlooked in intervention strategies to promote increased PAP. PMID:29854437

Associations of Body Mass Index, Motor Performance, and Perceived Athletic Competence with Physical Activity in Normal Weight and Overweight Children.

PubMed

Morrison, Kyle M; Cairney, John; Eisenmann, Joe; Pfeiffer, Karin; Gould, Dan

2018-01-01

Children who are overweight and obese display lower physical activity levels than normal weight peers. Measures of weight status, perceived motor competence, and motor skill performance have been identified as potential correlates explaining this discrepancy. 1881 children (955 males; 926 females; 9.9 years) were assessed as part of the Physical Health Activity Study Team project. The age, habitual physical activity participation (PAP), body mass index (BMI), socioeconomic status (SES), motor performance (MP), and perceived athletic competence (PAC) of each child included were assessed. Gender-specific linear regression analyses (main effects model) were conducted to identify the percent variance in PAP explained by the following variables: BMI, MP, and PAC. For males, 18.3% of the variance in PAP was explained by BMI, MP, and PAC. PAC explained 17% of the variance, while MP, BMI, and SES only accounted for 0.6%, 0.7%, and 0.5%, respectively. PAC explained 17.5% of PAP variance in females; MP explained 0.8%. BMI, SES, and chronological age were not significant correlates of PAP in girls. An established repertoire of motor skill performance has been seen as a vehicle to PAP in children; however, this study indicates that PAC should not be overlooked in intervention strategies to promote increased PAP.

Mechanisms of mindfulness training: Monitor and Acceptance Theory (MAT).

PubMed

Lindsay, Emily K; Creswell, J David

2017-02-01

Despite evidence linking trait mindfulness and mindfulness training with a broad range of effects, still little is known about its underlying active mechanisms. Mindfulness is commonly defined as (1) the ongoing monitoring of present-moment experience (2) with an orientation of acceptance. Building on conceptual, clinical, and empirical work, we describe a testable theoretical account to help explain mindfulness effects on cognition, affect, stress, and health outcomes. Specifically, Monitor and Acceptance Theory (MAT) posits that (1), by enhancing awareness of one's experiences, the skill of attention monitoring explains how mindfulness improves cognitive functioning outcomes, yet this same skill can increase affective reactivity. Second (2), by modifying one's relation to monitored experience, acceptance is necessary for reducing affective reactivity, such that attention monitoring and acceptance skills together explain how mindfulness improves negative affectivity, stress, and stress-related health outcomes. We discuss how MAT contributes to mindfulness science, suggest plausible alternatives to the account, and offer specific predictions for future research. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mechanisms of Mindfulness Training: Monitor and Acceptance Theory (MAT)1

PubMed Central

Lindsay, Emily K.; Creswell, J. David

2016-01-01

Despite evidence linking trait mindfulness and mindfulness training with a broad range of effects, still little is known about its underlying active mechanisms. Mindfulness is commonly defined as (1) the ongoing monitoring of present-moment experience (2) with an orientation of acceptance. Building on conceptual, clinical, and empirical work, we describe a testable theoretical account to help explain mindfulness effects on cognition, affect, stress, and health outcomes. Specifically, Monitor and Acceptance Theory (MAT) posits that (1), by enhancing awareness of one’s experiences, the skill of attention monitoring explains how mindfulness improves cognitive functioning outcomes, yet this same skill can increase affective reactivity. Second (2), by modifying one’s relation to monitored experience, acceptance is necessary for reducing affective reactivity, such that attention monitoring and acceptance skills together explain how mindfulness improves negative affectivity, stress, and stress-related health outcomes. We discuss how MAT contributes to mindfulness science, suggest plausible alternatives to the account, and offer specific predictions for future research. PMID:27835764

The Association Between 25 Hydroxyvitamin D and Airway Obstruction in Asthma.

PubMed

Hutchinson, K; Kerley, C; Cormican, L; Rochev, Y; Faul, J

2016-03-10

Since Vitamin D has anti-inflammatory effects we wondered whether the association between low serum 25OHD and airway obstruction in moderate persistent asthma might be explained by inflammatory pathways that worsen asthma. All subjects examined were Irish Caucasians with moderate persistent asthma and none took systemic steroid therapy. In addition to computerized spirometry, we measured BMI, serum 25-hydroxyvitamin D (25OHD), total IgE, Eosinophil Cationic Protein (ECP), and high sensitive C- reactive protein (hs-CRP). One hundred (47 male) subjects completed the testing. Within single level of asthma severity, 25OHD levels were related to post-bronchodilator FEV1/FVC (r = 0.26, p< 0.01), but multiple linear regression analysis demonstrated that the association was not explained by obesity or inflammatory markers. We find a relationship exists between airway obstruction and 25OHD levels in asthmatic adults, and the effect is not explained by the presence of potential confounders such as obesity, allergy and systemic inflammation.

Collective Efficacy in Sports and Physical Activities: Perceived Emotional Synchrony and Shared Flow.

PubMed

Zumeta, Larraitz N; Oriol, Xavier; Telletxea, Saioa; Amutio, Alberto; Basabe, Nekane

2015-01-01

This cross-sectional study analyzes the relationship between collective efficacy and two psychosocial processes involved in collective sport-physical activities. It argues that in-group identification and fusion with the group will affect collective efficacy (CE). A sample of 276 university students answered different scales regarding their participation in collective physical and sport activities. Multiple-mediation analyses showed that shared flow and perceived emotional synchrony mediate the relationship between in-group identification and CE, whereas the relationship between identity fusion and CE was only mediated by perceived emotional synchrony. Results suggest that both psychosocial processes explain the positive effects of in-group identification and identity fusion with the group in collective efficacy. Specifically, the role of perceived emotional synchrony in explaining the positive effects of participation in collective sport-physical activities is underlined. In sum, this study highlights the utility of collective actions and social identities to explain the psychosocial processes related to collective efficacy in physical and sports activities. Finally, practical implications are discussed.

Collective Efficacy in Sports and Physical Activities: Perceived Emotional Synchrony and Shared Flow

PubMed Central

Zumeta, Larraitz N.; Oriol, Xavier; Telletxea, Saioa; Amutio, Alberto; Basabe, Nekane

2016-01-01

This cross-sectional study analyzes the relationship between collective efficacy and two psychosocial processes involved in collective sport-physical activities. It argues that in-group identification and fusion with the group will affect collective efficacy (CE). A sample of 276 university students answered different scales regarding their participation in collective physical and sport activities. Multiple-mediation analyses showed that shared flow and perceived emotional synchrony mediate the relationship between in-group identification and CE, whereas the relationship between identity fusion and CE was only mediated by perceived emotional synchrony. Results suggest that both psychosocial processes explain the positive effects of in-group identification and identity fusion with the group in collective efficacy. Specifically, the role of perceived emotional synchrony in explaining the positive effects of participation in collective sport-physical activities is underlined. In sum, this study highlights the utility of collective actions and social identities to explain the psychosocial processes related to collective efficacy in physical and sports activities. Finally, practical implications are discussed. PMID:26779077

Sleep on your memory traces: How sleep effects can be explained by Act-In, a functional memory model.

PubMed

Cherdieu, Mélaine; Versace, Rémy; Rey, Amandine E; Vallet, Guillaume T; Mazza, Stéphanie

2018-06-01

Numerous studies have explored the effect of sleep on memory. It is well known that a period of sleep, compared to a similar period of wakefulness, protects memories from interference, improves performance, and might also reorganize memory traces in a way that encourages creativity and rule extraction. It is assumed that these benefits come from the reactivation of brain networks, mainly involving the hippocampal structure, as well as from their synchronization with neocortical networks during sleep, thereby underpinning sleep-dependent memory consolidation and reorganization. However, this memory reorganization is difficult to explain within classical memory models. The present paper aims to describe whether the influence of sleep on memory could be explained using a multiple trace memory model that is consistent with the concept of embodied cognition: the Act-In (activation-integration) memory model. We propose an original approach to the results observed in sleep research on the basis of two simple mechanisms, namely activation and integration. Copyright © 2017 Elsevier Ltd. All rights reserved.

Environmental, biological and anthropogenic effects on grizzly bear body size: temporal and spatial considerations.

PubMed

Nielsen, Scott E; Cattet, Marc R L; Boulanger, John; Cranston, Jerome; McDermid, Greg J; Shafer, Aaron B A; Stenhouse, Gordon B

2013-09-08

Individual body growth is controlled in large part by the spatial and temporal heterogeneity of, and competition for, resources. Grizzly bears (Ursus arctos L.) are an excellent species for studying the effects of resource heterogeneity and maternal effects (i.e. silver spoon) on life history traits such as body size because their habitats are highly variable in space and time. Here, we evaluated influences on body size of grizzly bears in Alberta, Canada by testing six factors that accounted for spatial and temporal heterogeneity in environments during maternal, natal and 'capture' (recent) environments. After accounting for intrinsic biological factors (age, sex), we examined how body size, measured in mass, length and body condition, was influenced by: (a) population density; (b) regional habitat productivity; (c) inter-annual variability in productivity (including silver spoon effects); (d) local habitat quality; (e) human footprint (disturbances); and (f) landscape change. We found sex and age explained the most variance in body mass, condition and length (R(2) from 0.48-0.64). Inter-annual variability in climate the year before and of birth (silver spoon effects) had detectable effects on the three-body size metrics (R(2) from 0.04-0.07); both maternal (year before birth) and natal (year of birth) effects of precipitation and temperature were related with body size. Local heterogeneity in habitat quality also explained variance in body mass and condition (R(2) from 0.01-0.08), while annual rate of landscape change explained additional variance in body length (R(2) of 0.03). Human footprint and population density had no observed effect on body size. These results illustrated that body size patterns of grizzly bears, while largely affected by basic biological characteristics (age and sex), were also influenced by regional environmental gradients the year before, and of, the individual's birth thus illustrating silver spoon effects. The magnitude of the silver spoon effects was on par with the influence of contemporary regional habitat productivity, which showed that both temporal and spatial influences explain in part body size patterns in grizzly bears. Because smaller bears were found in colder and less-productive environments, we hypothesize that warming global temperatures may positively affect body mass of interior bears.

Himalayan tectonics explained by extrusion of a low-viscosity crustal channel coupled to focused surface denudation.

PubMed

Beaumont, C; Jamieson, R A; Nguyen, M H; Lee, B

2001-12-13

Recent interpretations of Himalayan-Tibetan tectonics have proposed that channel flow in the middle to lower crust can explain outward growth of the Tibetan plateau, and that ductile extrusion of high-grade metamorphic rocks between coeval normal- and thrust-sense shear zones can explain exhumation of the Greater Himalayan sequence. Here we use coupled thermal-mechanical numerical models to show that these two processes-channel flow and ductile extrusion-may be dynamically linked through the effects of surface denudation focused at the edge of a plateau that is underlain by low-viscosity material. Our models provide an internally self-consistent explanation for many observed features of the Himalayan-Tibetan system.

Inter-individual Differences in the Effects of Aircraft Noise on Sleep Fragmentation.

PubMed

McGuire, Sarah; Müller, Uwe; Elmenhorst, Eva-Maria; Basner, Mathias

2016-05-01

Environmental noise exposure disturbs sleep and impairs recuperation, and may contribute to the increased risk for (cardiovascular) disease. Noise policy and regulation are usually based on average responses despite potentially large inter-individual differences in the effects of traffic noise on sleep. In this analysis, we investigated what percentage of the total variance in noise-induced awakening reactions can be explained by stable inter-individual differences. We investigated 69 healthy subjects polysomnographically (mean ± standard deviation 40 ± 13 years, range 18-68 years, 32 male) in this randomized, balanced, double-blind, repeated measures laboratory study. This study included one adaptation night, 9 nights with exposure to 40, 80, or 120 road, rail, and/or air traffic noise events (including one noise-free control night), and one recovery night. Mixed-effects models of variance controlling for reaction probability in noise-free control nights, age, sex, number of noise events, and study night showed that 40.5% of the total variance in awakening probability and 52.0% of the total variance in EEG arousal probability were explained by inter-individual differences. If the data set was restricted to nights (4 exposure nights with 80 noise events per night), 46.7% of the total variance in awakening probability and 57.9% of the total variance in EEG arousal probability were explained by inter-individual differences. The results thus demonstrate that, even in this relatively homogeneous, healthy, adult study population, a considerable amount of the variance observed in noise-induced sleep disturbance can be explained by inter-individual differences that cannot be explained by age, gender, or specific study design aspects. It will be important to identify those at higher risk for noise induced sleep disturbance. Furthermore, the custom to base noise policy and legislation on average responses should be re-assessed based on these findings. © 2016 Associated Professional Sleep Societies, LLC.

An economic theory of cigarette addiction.

PubMed

Suranovic, S M; Goldfarb, R S; Leonard, T C

1999-01-01

In this paper we present a model in which individuals act in their own best interest, to explain many behaviors associated with cigarette addiction. There are two key features of the model. First, there is an explicit representation of the withdrawal effects experienced when smokers attempt to quit smoking. Second, there is explicit recognition that the negative effects of smoking generally appear late in an individual's life. Among the things we use the model to explain are: (1) how individuals can become trapped in their decision to smoke; (2) the conditions under which cold-turkey quitting and gradual quitting may occur; and (3) a reason for the existence of quit-smoking treatments.

Kinetic model for thin film stress including the effect of grain growth

NASA Astrophysics Data System (ADS)

Chason, Eric; Engwall, A. M.; Rao, Z.; Nishimura, T.

2018-05-01

Residual stress during thin film deposition is affected by the evolution of the microstructure. This can occur because subsurface grain growth directly induces stress in the film and because changing the grain size at the surface affects the stress in new layers as they are deposited. We describe a new model for stress evolution that includes both of these effects. It is used to explain stress in films that grow with extensive grain growth (referred to as zone II) so that the grain size changes throughout the thickness of the layer as the film grows. Equations are derived for different cases of high or low atomic mobility where different assumptions are used to describe the diffusion of atoms that are incorporated into the grain boundary. The model is applied to measurements of stress and grain growth in evaporated Ni films. A single set of model parameters is able to explain stress evolution in films grown at multiple temperatures and growth rates. The model explains why the slope of the curvature measurements changes continuously with thickness and attributes it to the effect of grain size on new layers deposited on the film.

Effects of soil tillage on the microwave emission of soils

NASA Technical Reports Server (NTRS)

Jackson, T. J.; Koopman, G. J.; Oneill, P. E.; Wang, J. R.

1985-01-01

In order to understand the interactions of soil properties and microwave emission better, a series of field experiments were conducted in 1984. Small plots were measured with a truck-mounted passive microwave radiometer operating at 1.4 GHz. These data were collected concurrent with ground observations of soil moisture and bulk density. Treatment effects studied included different soil moisture contents and bulk densities. Evaluations of the data have shown that commonly used models of the dielectric properties of wet soils do not explain the observations obtained in these experiments. This conclusion was based on the fact that the roughness parameters determined through optimization were significantly larger than those observed in similar investigations. These discrepancies are most likely due to the soil structure. Commonly used models assume a homogeneous three phase mixture of soil solids, air and water. Under tilled conditions the soil is actually a two phase mixture of aggregates and voids. Appropriate dielectric models for this tilled condition were evaluated and found to explain the observations. These results indicate that previous conclusions concerning the effects of surface roughness in tilled fields may be incorrect, and they may explain some of the inconsistencies encountered in roughness modeling.

Influence of the large-small split effect on strategy choice in complex subtraction.

PubMed

Xiang, Yan Hui; Wu, Hao; Shang, Rui Hong; Chao, Xiaomei; Ren, Ting Ting; Zheng, Li Ling; Mo, Lei

2018-04-01

Two main theories have been used to explain the arithmetic split effect: decision-making process theory and strategy choice theory. Using the inequality paradigm, previous studies have confirmed that individuals tend to adopt a plausibility-checking strategy and a whole-calculation strategy to solve large and small split problems in complex addition arithmetic, respectively. This supports strategy choice theory, but it is unknown whether this theory also explains performance in solving different split problems in complex subtraction arithmetic. This study used small, intermediate and large split sizes, with each split condition being further divided into problems requiring and not requiring borrowing. The reaction times (RTs) for large and intermediate splits were significantly shorter than those for small splits, while accuracy was significantly higher for large and middle splits than for small splits, reflecting no speed-accuracy trade-off. Further, RTs and accuracy differed significantly between the borrow and no-borrow conditions only for small splits. This study indicates that strategy choice theory is suitable to explain the split effect in complex subtraction arithmetic. That is, individuals tend to choose the plausibility-checking strategy or the whole-calculation strategy according to the split size. © 2016 International Union of Psychological Science.

Making the Most of Small Effects

ERIC Educational Resources Information Center

Thompson, Ross A.

2009-01-01

The idea that classroom social ecologies are shaped by the aggregate effects of peers' prior care experiences is provocative, even though the evidence is weak that this explains the small and diminishing effect of childcare experience in the National Institute of Child Health and Human Development study. Small effects may indeed be small effects,…

Common Language Effect Size for Multiple Treatment Comparisons

ERIC Educational Resources Information Center

Liu, Xiaofeng Steven

2015-01-01

Researchers who need to explain treatment effects to laypeople can translate Cohen's effect size (standardized mean difference) to a common language effect size--a probability of a random observation from one population being larger than a random observation from the other population. This common language effect size can be extended to represent…

The Effect of Training Procedures on the Overlearning Reversal Effect in Young Children

ERIC Educational Resources Information Center

Casey, M. Beth

1975-01-01

Investigated the effect of correction and noncorrection procedures on the occurrence of the overlearning reversal effect (ORE) in 80 children 4-6 years of age. Results showing the existence of ORE at the preschool level are explained in terms of a response-switching strategy. (GO)

Age and Environmental Concern: Some Specification of Effects.

ERIC Educational Resources Information Center

Honnold, Julie A.

1984-01-01

Distinguishes possible aging, cohort, and period effects, explaining time series differences by age groups in the General Social Survey data. Results indicate that the decline in environmental concern among most age groups can be accounted for by period effects, but an aging effect is important among young adults. (Author/JN)

Climate and Human Pressure Constraints Co-Explain Regional Plant Invasion at Different Spatial Scales

PubMed Central

García-Baquero, Gonzalo; Caño, Lidia; Biurrun, Idoia; García-Mijangos, Itziar; Loidi, Javier; Herrera, Mercedes

2016-01-01

Alien species invasion represents a global threat to biodiversity and ecosystems. Explaining invasion patterns in terms of environmental constraints will help us to assess invasion risks and plan control strategies. We aim to identify plant invasion patterns in the Basque Country (Spain), and to determine the effects of climate and human pressure on that pattern. We modeled the regional distribution of 89 invasive plant species using two approaches. First, distance-based Moran’s eigenvector maps were used to partition variation in the invasive species richness, S, into spatial components at broad and fine scales; redundancy analysis was then used to explain those components on the basis of climate and human pressure descriptors. Second, we used generalized additive mixed modeling to fit species-specific responses to the same descriptors. Climate and human pressure descriptors have different effects on S at different spatial scales. Broad-scale spatially structured temperature and precipitation, and fine-scale spatially structured human population density and percentage of natural and semi-natural areas, explained altogether 38.7% of the total variance. The distribution of 84% of the individually tested species was related to either temperature, precipitation or both, and 68% was related to either population density or natural and semi-natural areas, displaying similar responses. The spatial pattern of the invasive species richness is strongly environmentally forced, mainly by climate factors. Since individual species responses were proved to be both similarly constrained in shape and explained variance by the same environmental factors, we conclude that the pattern of invasive species richness results from individual species’ environmental preferences. PMID:27741276

The causes of dispersal and the cost of carry-over effects for an endangered bird in a dynamic wetland landscape.

PubMed

Robertson, Ellen P; Fletcher, Robert J; Austin, James D

2017-07-01

The decision to disperse or remain philopatric between breeding seasons has important implications for both ecology and evolution, including the potential for carry-over effects, where an individual's previous history affects its current performance. Carry-over effects are increasingly documented although underlying mechanisms remain unclear. Here we test for potential carry-over effects and their mechanisms by uniting hypotheses for the causes and consequences of habitat selection and dispersal across space and time. We linked hypotheses regarding different types of factors and information (environmental conditions, personal and public information) predicted to impact reproductive success and dispersal for an endangered, wetland-dependent bird, the snail kite (Rostrhamus sociabilis plumbeus). To do so, we coupled structural equation modelling with 20 years of mark-recapture and nesting data across the breeding range of this species to isolate potential direct and indirect effects of these factors. We found that water depth at nest sites explained subsequent emigration rates via an indirect path through the use of personal, not public, information. Importantly, we found that these dispersers tended to initiate nests later the following breeding season. This pattern explained a phenological mismatch of nesting with hydrological conditions, whereby immigrants tended to nest later, late nesters tended to experience lower water depths, higher nest failure occurred at lower water depths and higher nest failure explained subsequent breeding dispersal. These results identified a novel potential mechanism for carry-over effects: a phenological mismatch with environmental conditions (water depth) that occurred potentially due to time costs of dispersal. Our results also highlighted a substantial benefit of philopatry - earlier initiation of reproduction - which allows philopatric individuals to better coincide with environmental conditions that are beneficial for successful reproduction. These results have implications for our mechanistic understanding and prediction of carryover effects, and emphasize that local conservation strategies, such as water management, can explain future demography at distant sites connected through dispersal. © 2017 The Authors. Journal of Animal Ecology © 2017 British Ecological Society.

The effects of landscape position on plant species density: Evidence of past environmental effects in a coastal wetland

USGS Publications Warehouse

Grace, J.B.; Guntenspergen, G.R.

1999-01-01

Here we propose that an important cause of variation in species density may be prior environmental conditions that continue to influence current patterns. In this paper we investigated the degree to which species density varies with location within the landscape, independent of contemporaneous environmental conditions. The area studied was a coastal marsh landscape subject to periodic storm events. To evaluate the impact of historical effects, it was assumed that the landscape position of a plot relative to the river's mouth ('distance from sea') and to the edge of a stream channel ('distance from shore') would correlate with the impact of prior storm events, an assumption supported by previous studies. To evaluate the importance of spatial location on species density, data were collected from five sites located at increasing distances from the river's mouth along the Middle Pearl River in Louisiana. At each site, plots were established systematically along transects perpendicular to the shoreline. For each of the 175 Plots, we measured elevation, soil salinity, percent of plot recently disturbed, percent of sunlight captured by the plant canopy (as a measure of plant abundance), and plant species density. Structural equation analysis ascertained the degree to which landscape position variables explained variation in species density that could not be explained by current environmental indicators. Without considering landscape variables, 54% of the variation in species density could be explained by the effects of salinity, flooding, and plant abundance. When landscape variables were included, distance from shore was unimportant but distance from sea explained an additional 12% of the variance in species density (R2 of final model = 66%). Based on these results it appears that at least some of the otherwise unexplained variation in species density can be attributed to landscape position, and presumably previous storm events. We suggest that future studies may gain additional insight into the factors controlling current patterns of species density by examining the effects of position within the landscape.

Adult height variants affect birth length and growth rate in children.

PubMed

Paternoster, Lavinia; Howe, Laura D; Tilling, Kate; Weedon, Michael N; Freathy, Rachel M; Frayling, Timothy M; Kemp, John P; Smith, George Davey; Timpson, Nicholas J; Ring, Susan M; Evans, David M; Lawlor, Debbie A

2011-10-15

Previous studies identified 180 single nucleotide polymorphisms (SNPs) associated with adult height, explaining ∼10% of the variance. The age at which these begin to affect growth is unclear. We modelled the effect of these SNPs on birth length and childhood growth. A total of 7768 participants in the Avon Longitudinal Study of Parents and Children had data available. Individual growth trajectories from 0 to 10 years were estimated using mixed-effects linear spline models and differences in trajectories by individual SNPs and allelic score were determined. The allelic score was associated with birth length (0.026 cm increase per 'tall' allele, SE = 0.003, P = 1 × 10(-15), equivalent to 0.017 SD). There was little evidence of association between the allelic score and early infancy growth (0-3 months), but there was evidence of association between the allelic score and later growth. This association became stronger with each consecutive growth period, per 'tall' allele per month effects were 0.015 SD (3 months-1 year, SE = 0.004), 0.023 SD (1-3 years, SE = 0.003) and 0.028 SD (3-10 years, SE = 0.003). By age 10, the mean height difference between individuals with ≤170 versus ≥191 'tall' alleles (the top and bottom 10%) was 4.7 cm (0.8 SD), explaining ∼5% of the variance. There was evidence of associations with specific growth periods for some SNPs (rs3791675, EFEMP1 and rs6569648, L3MBTL3) and supportive evidence for previously reported age-dependent effects of HHIP and SOCS2 SNPs. SNPs associated with adult height influence birth length and have an increasing effect on growth from late infancy through to late childhood. By age 10, they explain half the height variance (∼5%) of that explained in adults (∼10%).

Explaining individual differences in alcohol intake in adults: evidence for genetic and cultural transmission?

PubMed

van Beek, Jenny H D A; de Moor, Marleen H M; Geels, Lot M; Willemsen, Gonneke; Boomsma, Dorret I

2014-03-01

The current study aimed to describe what proportion of variation in adult alcohol intake is attributable to genetic differences among individuals and what proportion to differences in environmental experiences individuals have been exposed to. Effects of age, gender, spousal resemblance, and cultural transmission of alcohol intake from parents to offspring were taken into account. In a twin-family design, the effects of genetic and cultural transmission and shared and nonshared environment on alcohol intake were estimated with genetic structural equation models. Data originated from adult twins, their siblings, parents (n = 12,587), and spouses (n = 429) registered with the population-based Netherlands Twin Register (63.5% female; ages 18-97 years). Alcohol intake (grams per day) was higher among men than women and increased with age. Broad-sense heritability estimates were similar across sex and age (53%). Spousal resemblance was observed (r = .39) but did not significantly affect the heritability estimates. No effects of cultural transmission were detected. In total, 23% of the variation in alcohol intake was explained by additive genetic effects, 30% by dominant (nonadditive) gene action, and 47% by environmental effects that were not shared among family members. Individual differences in adult alcohol intake are explained by genetic and individual-specific environmental effects. The same genes are expressed in males and females and in younger and older participants. A substantial part of the heritability of alcohol intake is attributable to nonadditive gene action. Effects of cultural transmission that have been reported in adolescence are not present in adulthood.

Executive Function, Behavioral Self-Regulation, and School Related Well-Being Did Not Mediate the Effect of School-Based Physical Activity on Academic Performance in Numeracy in 10-Year-Old Children. The Active Smarter Kids (ASK) Study.

PubMed

Aadland, Katrine N; Aadland, Eivind; Andersen, John R; Lervåg, Arne; Moe, Vegard F; Resaland, Geir K; Ommundsen, Yngvar

2018-01-01

Inconsistent findings exist for the effect of school-based physical activity interventions on academic performance. The Active Smarter Kids (ASK) study revealed a favorable intervention effect of school-based physical activity on academic performance in numeracy in a subsample of 10-year-old elementary schoolchildren performing poorer at baseline in numeracy. Aiming to explain this finding, we investigated the mediating effects of executive function, behavioral self-regulation, and school related well-being in the relation between the physical activity intervention and child's performance in numeracy. An ANCOVA model with latent variable structural equation modeling was estimated using data from 360 children (the lower third in academic performance in numeracy at baseline). The model consisted of the three latent factors as mediators; executive function, behavioral self-regulation, and school related well-being. We found no mediating effects of executive function, behavioral self-regulation or school related well-being in the relationship between the ASK intervention and academic performance in numeracy ( p ≥ 0.256). Our results suggest that the effect of the intervention on performance in numeracy in the present sample is not explained by change in executive function, behavioral self-regulation, or school related well-being. We suggest this finding mainly could be explained by the lack of effect of the intervention on the mediators, which might be due to an insufficient dose of physical activity. Trial registration: Clinicaltrials.gov registry, trial registration number: NCT02132494.

Executive Function, Behavioral Self-Regulation, and School Related Well-Being Did Not Mediate the Effect of School-Based Physical Activity on Academic Performance in Numeracy in 10-Year-Old Children. The Active Smarter Kids (ASK) Study

PubMed Central

Aadland, Katrine N.; Aadland, Eivind; Andersen, John R.; Lervåg, Arne; Moe, Vegard F.; Resaland, Geir K.; Ommundsen, Yngvar

2018-01-01

Inconsistent findings exist for the effect of school-based physical activity interventions on academic performance. The Active Smarter Kids (ASK) study revealed a favorable intervention effect of school-based physical activity on academic performance in numeracy in a subsample of 10-year-old elementary schoolchildren performing poorer at baseline in numeracy. Aiming to explain this finding, we investigated the mediating effects of executive function, behavioral self-regulation, and school related well-being in the relation between the physical activity intervention and child’s performance in numeracy. An ANCOVA model with latent variable structural equation modeling was estimated using data from 360 children (the lower third in academic performance in numeracy at baseline). The model consisted of the three latent factors as mediators; executive function, behavioral self-regulation, and school related well-being. We found no mediating effects of executive function, behavioral self-regulation or school related well-being in the relationship between the ASK intervention and academic performance in numeracy (p ≥ 0.256). Our results suggest that the effect of the intervention on performance in numeracy in the present sample is not explained by change in executive function, behavioral self-regulation, or school related well-being. We suggest this finding mainly could be explained by the lack of effect of the intervention on the mediators, which might be due to an insufficient dose of physical activity. Trial registration: Clinicaltrials.gov registry, trial registration number: NCT02132494. PMID:29541050

Indoor Radon: The Deadliest Pollutant.

ERIC Educational Resources Information Center

Kerr, Richard A.

1988-01-01

Describes the origin, occurrence, and effects of radon gas. Cites studies which attribute 5,000 to 20,000 deaths per year to radon exposure and the synergistic effect between radon and smoking. Explains ways to reduce risks. (RT)

Emittance growth due to multiple passes through H-minus stripping foil in Booster

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardner, C. J.

Expressions for transverse emittance growth due to turn-by-turn passes through the H-minus stripping foil in Booster are developed here from simple principles of statistics and simple assumptions about the initial distribution of particles incident on the foil. These are meant to complement work already presented by Zeno [1, 2, 3] and Brown [4]. The expressions show that while the average emittance hEi of the distribution simply increases linearly with turn number, the emittance E based on the mean square particle position does so with an additional oscillatory term that depends on the machine tune. It is shown that this termmore » can be ignored as long as the turn number is su ciently large and the tune is su ciently far from integer and half-integer values. Under these conditions the relation between hEi and E is simply hEi = 2 E. This relation is shown to hold for a Gaussian distribution that is matched to the machine lattice. Two symmetry conditions which help characterize the particle distribution are identi ed. These provide justi cation for calling E an emittance. It is shown that if the conditions are satis ed by the initial distribution, they will not be satis ed after a single traversal of the foil and one turn around the machine. However, on subsequent turns the distribution can (and does) return to satisfying the conditions. Moreover, for su ciently large turn number, the symmetry conditions are approximately satis ed. As already noted in [4], the emittance growth per turn is proportional to the lattice beta at the foil and the mean square angular kick received by protons passing through the foil. We take the former to be 5 m. The latter is obtained from simulations performed with the code TRIM [5]. Having these numbers in hand, actual numbers for emittance growth are presented. The reader may wish to start with Section 11 and refer to previous sections as needed or desired.« less

Adult mental health needs and expenditure in Australia.

PubMed

Burgess, Philip; Pirkis, Jane; Buckingham, Bill; Burns, Jane; Eagar, Kathy; Eckstein, Gary

2004-06-01

Relatively little international work has examined whether mental health resource allocation matches need. This study aimed to determine whether adult mental health resources in Australia are being distributed equitably. Individual measures of need were extrapolated to Australian Areas, and Area-based proxies of need were considered. Particular attention was paid to the prevalence of mental health problems, since this is arguably the most objective measure of need. The extent to which these measures predicted public sector, private sector and total adult mental health expenditure at an Area level was examined. In the public sector, 41.6% of expenditure variation was explained by the prevalence of affective disorders, personality disorders, cognitive impairment and psychosis, as well as the Area's level of economic resources and State/Territory effects. In the private sector, 72.4% of expenditure variation was explained by service use and State/Territory effects (with an alternative model incorporating service use and State/Territory supply of private psychiatrists explaining 69.4% of expenditure variation). A relatively high proportion (58.7%) of total expenditure variation could be explained by service utilisation and State/Territory effects. For services to be delivered equitably, the majority of variation in expenditure would have to be accounted for by appropriate measures of need. The best model for public sector expenditure included an appropriate measure of need but had relatively poor explanatory power. The models for private sector and total expenditure had greater explanatory power, but relied on less appropriate measures of need. It is concluded that mental health services in Australia are not yet being delivered equitably.

Neural dynamics of grouping and segmentation explain properties of visual crowding.

PubMed

Francis, Gregory; Manassi, Mauro; Herzog, Michael H

2017-07-01

Investigations of visual crowding, where a target is difficult to identify because of flanking elements, has largely used a theoretical perspective based on local interactions where flanking elements pool with or substitute for properties of the target. This successful theoretical approach has motivated a wide variety of empirical investigations to identify mechanisms that cause crowding, and it has suggested practical applications to mitigate crowding effects. However, this theoretical approach has been unable to account for a parallel set of findings that crowding is influenced by long-range perceptual grouping effects. When the target and flankers are perceived as part of separate visual groups, crowding tends to be quite weak. Here, we describe how theoretical mechanisms for grouping and segmentation in cortical neural circuits can account for a wide variety of these long-range grouping effects. Building on previous work, we explain how crowding occurs in the model and explain how grouping in the model involves connected boundary signals that represent a key aspect of visual information. We then introduce new circuits that allow nonspecific top-down selection signals to flow along connected boundaries or within a surface contained by boundaries and thereby induce a segmentation that can separate the visual information corresponding to the flankers from the visual information corresponding to the target. When such segmentation occurs, crowding is shown to be weak. We compare the model's behavior to 5 sets of experimental findings on visual crowding and show that the model does a good job explaining the key empirical findings. (PsycINFO Database Record (c) 2017 APA, all rights reserved).

Two Mechanisms: The Role of Social Capital and Industrial Pollution Exposure in Explaining Racial Disparities in Self-Rated Health

PubMed Central

Ard, Kerry; Colen, Cynthia; Becerra, Marisol; Velez, Thelma

2016-01-01

This study provides an empirical test of two mechanisms (social capital and exposure to air pollution) that are theorized to mediate the effect of neighborhood on health and contribute to racial disparities in health outcomes. To this end, we utilize the Social Capital Benchmark Study, a national survey of individuals nested within communities in the United States, to estimate how multiple dimensions of social capital and exposure to air pollution, explain racial disparities in self-rated health. Our main findings show that when controlling for individual-confounders, and nesting within communities, our indicator of cognitive bridging, generalized trust, decreases the gap in self-rated health between African Americans and Whites by 84%, and the gap between Hispanics and Whites by 54%. Our other indicator of cognitive social capital, cognitive linking as represented by engagement in politics, decreases the gap in health between Hispanics and Whites by 32%, but has little impact on African Americans. We also assessed whether the gap in health was explained by respondents’ estimated exposure to toxicity-weighted air pollutants from large industrial facilities over the previous year. Our results show that accounting for exposure to these toxins has no effect on the racial gap in self-rated health in these data. This paper contributes to the neighborhood effects literature by examining the impact that estimated annual industrial air pollution, and multiple measures of social capital, have on explaining the racial gap in health in a sample of individuals nested within communities across the United States. PMID:27775582

Two Mechanisms: The Role of Social Capital and Industrial Pollution Exposure in Explaining Racial Disparities in Self-Rated Health.

PubMed

Ard, Kerry; Colen, Cynthia; Becerra, Marisol; Velez, Thelma

2016-10-19

This study provides an empirical test of two mechanisms (social capital and exposure to air pollution) that are theorized to mediate the effect of neighborhood on health and contribute to racial disparities in health outcomes. To this end, we utilize the Social Capital Benchmark Study, a national survey of individuals nested within communities in the United States, to estimate how multiple dimensions of social capital and exposure to air pollution, explain racial disparities in self-rated health. Our main findings show that when controlling for individual-confounders, and nesting within communities, our indicator of cognitive bridging, generalized trust, decreases the gap in self-rated health between African Americans and Whites by 84%, and the gap between Hispanics and Whites by 54%. Our other indicator of cognitive social capital, cognitive linking as represented by engagement in politics, decreases the gap in health between Hispanics and Whites by 32%, but has little impact on African Americans. We also assessed whether the gap in health was explained by respondents' estimated exposure to toxicity-weighted air pollutants from large industrial facilities over the previous year. Our results show that accounting for exposure to these toxins has no effect on the racial gap in self-rated health in these data. This paper contributes to the neighborhood effects literature by examining the impact that estimated annual industrial air pollution, and multiple measures of social capital, have on explaining the racial gap in health in a sample of individuals nested within communities across the United States.

Effect size for the main cognitive function determinants in a large cross-sectional study.

PubMed

Mura, T; Amieva, H; Goldberg, M; Dartigues, J-F; Ankri, J; Zins, M; Berr, C

2016-11-01

The aim of our study was to examine the effect sizes of different cognitive function determinants in middle and early old age. Cognitive functions were assessed in 11 711 volunteers (45 to 75 years old), included in the French CONSTANCES cohort between January 2012 and May 2014, using the free and cued selective reminding test (FCSRT), verbal fluency tasks, digit-symbol substitution test (DSST) and trail making test (TMT), parts A and B. The effect sizes of socio-demographic (age, sex, education), lifestyle (alcohol, tobacco, physical activity), cardiovascular (diabetes, blood pressure) and psychological (depressive symptomatology) variables were computed as omega-squared coefficients (ω 2 ; part of the variation of a neuropsychological score that is independently explained by a given variable). These sets of variables explained from R 2 = 10% (semantic fluency) to R 2 = 26% (DSST) of the total variance. In all tests, socio-demographic variables accounted for the greatest part of the explained variance. Age explained from ω 2 = 0.5% (semantic fluency) to ω 2 = 7.5% (DSST) of the total score variance, gender from ω 2 = 5.2% (FCSRT) to a negligible part (semantic fluency or TMT) and education from ω 2 = 7.2% (DSST) to ω 2 = 1.4% (TMT-A). Behavioral, cardiovascular and psychological variables only slightly influenced the cognitive test results (all ω 2 < 0.8%, most ω 2 < 0.1%). Socio-demographic variables (age, gender and education) are the main variables associated with cognitive performance variations between 45 and 75 years of age in the general population. © 2016 EAN.

Alignment effects in beer mugs: Automatic action activation or response competition?

PubMed

Roest, Sander A; Pecher, Diane; Naeije, Lilian; Zeelenberg, René

2016-08-01

Responses to objects with a graspable handle are faster when the response hand and handle orientation are aligned (e.g., a key press with the right hand is required and the object handle is oriented to the right) than when they are not aligned. This effect could be explained by automatic activation of specific motor programs when an object is viewed. Alternatively, the effect could be explained by competition at the response level. Participants performed a reach-and-grasp or reach-and-button-press action with their left or right hand in response to the color of a beer mug. The alignment effect did not vary as a function of the type of action. In addition, the alignment effect disappeared in a go/no-go version of the task. The same results were obtained when participants made upright/inverted decisions, so that object shape was task-relevant. Our results indicate that alignment effects are not due to automatic motor activation of the left or right limb.

Pressure effect in cuprates - manifestation of Le Chatelier's principle

NASA Astrophysics Data System (ADS)

Kallio, A.; Bräysy, V.; Hissa, J.

We show that the pressure dependence of Tc, the Hall coefficient scaling, resistivities etc. can be explained by the chemical equilibrium of bosons and their decay products the fermions applying essentially the classical theory. Above a temperature TBL the bosons form a lattice, which causes diffusion term in τab-1. Treatment of equilibrium in a magnetic field explains the dependence of quantities like the penetration depth λab uponm the field.

Could the stellar magnetic field explain the structures in the AU Mic debris disk?

NASA Astrophysics Data System (ADS)

Sezestre, Élie; Augereau, Jean-Charles

2016-05-01

Recent SPHERE and reprocessed HST images of the edge-on AU Mic debris disk have revealed arch-like structures moving away from the star on unbound trajectories. No model in the literature can readily explain these features. Here, we explore the effect of the large-scale, stellar magnetic field on the dust dynamics. We show that our study may place constraints on the dust production location.

[The mechanism of action of cannabis and cannabinoids].

PubMed

Scholten, W K

2006-01-21

The effect ofcannabis can be explained on the basis of the function of the cannabinoid receptor system, which consists of CB receptors (CB1, CB2), endoligands to activate these receptors and an enzyme--fatty acid amidohydrolase--to metabolize the endoligands. The endoligands of the cannabinoid receptor system are arachidonic acid-like substances, and are called endocannabinoids. Indications exist that the body also contains arachidonic acid-like substances that inhibit fatty acid amido hydrolase. Various cannabinoids have diverse effects on the receptors, functioning as agonists, antagonists or partial antagonists, as well as affecting the vanilloid receptor. Many known effects ofcannabis can be explained on the basis of this mechanism of action as can the use ofcannabis in various conditions including multiple sclerosis, Parkinson's disease, glaucoma, nausea, vomiting and rheumatoid arthritis.

Anomalous hydrodynamics kicks neutron stars

DOE PAGES

Kaminski, Matthias; Uhlemann, Christoph F.; Bleicher, Marcus; ...

2016-06-28

Observations show that, at the beginning of their existence, neutron stars are accelerated briskly to velocities of up to a thousand kilometers per second. We argue that this remarkable effect can be explained as a manifestation of quantum anomalies on astrophysical scales. To theoretically describe the early stage in the life of neutron stars we use hydrodynamics as a systematic effective-field-theory framework. Within this framework, anomalies of the Standard Model of particle physics as underlying microscopic theory imply the presence of a particular set of transport terms, whose form is completely fixed by theoretical consistency. Here, the resulting chiral transportmore » effects in proto-neutron stars enhance neutrino emission along the internal magnetic field, and the recoil can explain the order of magnitude of the observed kick velocities.« less

Evaluation of the effectiveness factor along immobilized enzyme fixed-bed reactors: design of a reactor with naringinase covalently immobilized into glycophase-coated porous glass

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manjon, A.; Iborra, J.L.; Gomez, J.L.

A design equation is presented for packed-bed reactors containing immobilized enzymes in spherical porous particles with internal diffusion effects and obeying reversible one-intermediate Michaelis-Menten kinetics. The equation is also able to explain irreversible and competitive product inhibition kinetics. It allows the axial substrate profiles to be calculated and the dependence of the effectiveness factor along the reactor length to be continuously evaluated. The design equation was applied to explain the behavior of naringinase immobilized in Glycophase-coated porous glass operating in a packed-bed reactor and hydrolyzing both p-nitrophenyl-alpha-L-rhamnoside and naringin. The theoretically predicted results were found to fit well with experimentallymore » measured values. (Refs. 28).« less

Optogalvanic effect and laser-induced current oscillations in hollow-cathode lamps

NASA Astrophysics Data System (ADS)

Eldakli, Mohsan S. A.; Ivković, Saša S.; Obradović, Bratislav M.

2017-03-01

This paper presents a study of two commercial hollow-cathode lamps (HCLs) with the intention of demonstrating different phenomena in gas discharges. The optogalvanic effect in both HCLs is produced by a laser diode radiated at the wavelength that corresponds to neon transition 1s2-2p2 at 659.89 nm. The voltage-current characteristics of the lamps are explained using a classical theory of hollow-cathode discharge, while the optogalvanic signal is treated as a small perturbation of the discharge current. For certain values of voltage self-sustained current oscillations are observed in one of the HCLs. In the same HCL laser-induced optogalvanic dumped oscillations are detected. A phenomenological model that includes the effective circuit parameters of the discharge is used to explain the oscillation characteristics.

Playful Physics

NASA Technical Reports Server (NTRS)

Weaver, David

2008-01-01

Effectively communicate qualitative and quantitative information orally and in writing. Explain the application of fundamental physical principles to various physical phenomena. Apply appropriate problem-solving techniques to practical and meaningful problems using graphical, mathematical, and written modeling tools. Work effectively in collaborative groups.

Red Shifts with Obliquely Approaching Light Sources.

ERIC Educational Resources Information Center

Head, C. E.; Moore-Head, M. E.

1988-01-01

Refutes the Doppler effect as the explanation of large red shifts in the spectra of distant galaxies and explains the relativistic effects in which the light sources approach the observer obliquely. Provides several diagrams and graphs. (YP)

Discussion of “The relation between dilatancy, effective stress and dispersive pressure in granular avalanches” by P. Bartelt and O. Buser (DOI: 10.1007/s11440-016-0463-7)

USGS Publications Warehouse

Iverson, Richard M.; George, David L.

2016-01-01

A paper recently published by Bartelt and Buser (hereafter identified as “the authors”) aims to clarify relationships between granular dilatancy and dispersive pressure and to question the effective stress principle and its application to shallow granular avalanches (Bartelt and Buser in Act Geotech 11:549–557, 2). The paper also criticizes our own recent work, which utilizes the concepts of evolving dilatancy and effective stress to model the initiation and dynamics of water-saturated landslides and debris flows. Here we first explain why we largely agree with the authors’ views of dilatancy and dispersive pressure as they apply to depth-integrated granular avalanche models, and why we disagree with their views of effective stress and pore-fluid pressure. We conclude by explaining why the authors’ characterization of our recently developed D-Claw model is inaccurate.

Mentally walking through doorways causes forgetting: The location updating effect and imagination.

PubMed

Lawrence, Zachary; Peterson, Daniel

2016-01-01

Researchers have documented an intriguing phenomenon whereby simply walking through a doorway causes forgetting (the location updating effect). The Event Horizon Model is the most commonly cited theory to explain these data. Importantly, this model explains the effect without invoking the importance or reliance upon perceptual information (i.e., seeing oneself pass through the doorway). This generates the intriguing hypothesis that the effect may be demonstrated in participants who simply imagine walking through a doorway. Across two experiments, we explicitly test this hypothesis. Participants familiarised themselves with both real (Experiment 1) and virtual (Experiment 2) environments which served as the setting for their mental walk. They were then provided with an image to remember and were instructed to imagine themselves walking through the previously presented space. In both experiments, when the mental walk required participants to pass through a doorway, more forgetting occurred, consistent with the predictions laid out in the Event Horizon Model.

Eigenvalue Detonation of Combined Effects Aluminized Explosives

NASA Astrophysics Data System (ADS)

Capellos, Christos; Baker, Ernest; Balas, Wendy; Nicolich, Steven; Stiel, Leonard

2007-06-01

This paper reports on the development of theory and performance for recently developed combined effects aluminized explosives. Traditional high energy explosives used for metal pushing incorporate high loading percentages of HMX or RDX, whereas blast explosives incorporate some percentage of aluminum. However, the high blast explosives produce increased blast energies, with reduced metal pushing capability due to late time aluminum reaction. Metal pushing capability refers to the early volume expansion work produced during the first few volume expansions associated with cylinder wall velocities and Gurney energies. Our Recently developed combined effects aluminized explosives (PAX-29C, PAX-30, PAX-42) are capable of achieving excellent metal pushing and high blast energies. Traditional Chapman-Jouguet detonation theory does not explain the observed detonation states achieved by these combined effects explosives. This work demonstrates, with the use of cylinder expansion data and thermochemical code calculations (JAGUAR and CHEETAH), that eigenvalue detonation theory explains the observed behavior.

Antiepileptic drug effects on mood and behavior: molecular targets.

PubMed

Perucca, Piero; Mula, Marco

2013-03-01

With almost 100 years of clinical experience, antiepileptic drugs (AEDs) remain the mainstay of epilepsy treatment. They suppress epileptic seizures by acting on a variety of mechanisms and molecular targets involved in the regulation of neuronal excitability. These include inhibitory-GABAergic and excitatory-glutamatergic neurotransmission, as well as ion (sodium and calcium) conductance through voltage-gated channels. On the other hand, accruing evidence indicates that these mechanisms and targets are also implicated in the regulation of mood and behavior, which may explain why each AED is associated with specific psychotropic effects. These effects, however, cannot be explained solely on the basis of the known mode of action of each AED, and other mechanisms or targets are likely to be implicated. In this article, we review positive and negative effects of AEDs on mood and behavior, discuss putative underlying mechanisms, and highlight knowledge gaps which should be addressed in future studies. Copyright © 2012 Elsevier Inc. All rights reserved.

Evanescent radiation, quantum mechanics and the Casimir effect

NASA Technical Reports Server (NTRS)

Schatten, Kenneth H.

1989-01-01

An attempt to bridge the gap between classical and quantum mechanics and to explain the Casimir effect is presented. The general nature of chaotic motion is discussed from two points of view: the first uses catastrophe theory and strange attractors to describe the deterministic view of this motion; the underlying framework for chaos in these classical dynamic systems is their extreme sensitivity to initial conditions. The second interpretation refers to randomness associated with probabilistic dynamics, as for Brownian motion. The present approach to understanding evanescent radiation and its relation to the Casimir effect corresponds to the first interpretation, whereas stochastic electrodynamics corresponds to the second viewpoint. The nonlinear behavior of the electromagnetic field is also studied. This well-understood behavior is utilized to examine the motions of two orbiting charges and shows a closeness between the classical behavior and the quantum uncertainty principle. The evanescent radiation is used to help explain the Casimir effect.

A refined method for multivariate meta-analysis and meta-regression.

PubMed

Jackson, Daniel; Riley, Richard D

2014-02-20

Making inferences about the average treatment effect using the random effects model for meta-analysis is problematic in the common situation where there is a small number of studies. This is because estimates of the between-study variance are not precise enough to accurately apply the conventional methods for testing and deriving a confidence interval for the average effect. We have found that a refined method for univariate meta-analysis, which applies a scaling factor to the estimated effects' standard error, provides more accurate inference. We explain how to extend this method to the multivariate scenario and show that our proposal for refined multivariate meta-analysis and meta-regression can provide more accurate inferences than the more conventional approach. We explain how our proposed approach can be implemented using standard output from multivariate meta-analysis software packages and apply our methodology to two real examples. Copyright © 2013 John Wiley & Sons, Ltd.

The Effects of Inflation/Recession on Higher Education.

ERIC Educational Resources Information Center

Bowen, William G.

This document discusses the effects of inflation on colleges and universities. It attempts to explain the basic nature of the current financial problem so that more informed policy decisions can be made. The document discusses the effect of inflation on costs and the effects of inflation/recession on revenues. Chart 1 indicated the Halstead Higher…

Does Testing Impair Relational Processing? Failed Attempts to Replicate the Negative Testing Effect

ERIC Educational Resources Information Center

Rawson, Katherine A.; Wissman, Kathryn T.; Vaughn, Kalif E.

2015-01-01

Recent research on testing effects (i.e., practice tests are more effective than restudy for enhancing subsequent memory) has focused on explaining when and why testing enhances memory. Of particular interest for present purposes, Zaromb and Roediger (2010) reported evidence that testing effects in part reflect enhanced relational processing,…

Arthur H. Compton and Compton Scattering

Science.gov Websites

of X-rays, when he discovered the effect that is named after him in 1922. ... The Compton effect photon, when it interacts with matter. This effect demonstrates that light cannot be explained purely as overall momentum of the system is conserved. ... The explanation and measurement of the Compton effect

A Non-Relativistic Look at the Compton Effect

ERIC Educational Resources Information Center

Feller, Steve; Giri, Sandeep; Zakrasek, Nicholas; Affatigato, Mario

2014-01-01

In a usual modern physics class the Compton effect is used as the pedagogical model for introducing relativity into quantum effects. The shift in photon wavelengths is usually introduced and derived using special relativity. Indeed, this works well for explaining the effect. However, in the senior author's class one of the student coauthors…

The Giffen Effect: A Note on Economic Purposes.

ERIC Educational Resources Information Center

Williams, William D.

1990-01-01

Describes the Giffen effect: demand for a commodity increases as price increases. Explains how applying control theory eliminates the paradox that the Giffen effect presents to classic economics supply and demand theory. Notes the differences in how conventional demand theory and control theory treat consumer behavior. (CH)

Refutation Texts for Effective Climate Change Education

ERIC Educational Resources Information Center

Nussbaum, E. Michael; Cordova, Jacqueline R.; Rehmat, Abeera P.

2017-01-01

Refutation texts, which are texts that rebut scientific misconceptions and explain the normative concept, can be effective devices for addressing misconceptions and affecting conceptual change. However, few, if any, refutation texts specifically related to climate change have been validated for effectiveness. In this project, we developed and…

SERT: Self-Explanation Reading Training

ERIC Educational Resources Information Center

McNamara, Danielle S.

2004-01-01

This study examined the effects of providing reading strategy instruction to improve the effectiveness of self-explanation (i.e., explaining the meaning of information to oneself while reading). The effects of the reading strategy instruction, called Self-Explanation Reading Training (SERT), were examined both in terms of comprehension scores and…

A suggested mechanism for aluminum biotoxicity.

PubMed

Forbes, W F; Agwani, N

1994-11-21

Following earlier work on the relevance of silica (SiO2) and fluoride (F) to the biotoxicity of aluminum (Al), it is shown that relatively high risks of a measure of mental impairment are frequently associated with relatively low SiO2 and F in the drinking water available in different parts of Ontario. Also, because of a negative association between SiO2 and F concentrations in the treated water available in different municipalities, a low SiO2 concentration can account for the observed association involving high F concentrations, and low F concentrations can similarly account for associations involving high SiO2 concentrations. In the light of these observations, the biotoxic effects at low Al concentrations can be explained by assuming that interactions occur with membranes. Such interactions may be less likely at higher SiO2 and F concentrations, because at these concentrations, interactions between Al-, SiO2- and F-containing species are more important. Generally, the various associations with a measure of mental impairment can be explained on the assumption that F exerts a protective effect against the biotoxic effects of Al, as does SiO2 under certain conditions, but the effects of SiO2 only become important at higher SiO2 concentrations. The results from this and other studies suggest that the neurotoxic effects of Al depend on other water constituents. The results also indicate that absorption through the lung or skin, rather than through the stomach or the bowel, can better explain the reported associations.

Rearfoot eversion has indirect effects on plantar fascia tension by changing the amount of arch collapse.

PubMed

Lee, Sae Yong; Hertel, Jay; Lee, Sung Cheol

2010-01-01

Rearfoot eversion motion and arch height are believed to contribute to increased tension on the plantar fascia and arch collapse during gait but the specifics of these relationships are not clear. To examine the relationships among static arch height, rearfoot eversion, dynamic arch height, and plantar fascia tension. 28 healthy males participated. After static arch height was measured, the subjects were asked to run at 4.5m/s while frontal plane rearfoot motion, dynamic arch height, and ground reaction forces were collected. The relationships among variables were examined with bivariate correlations and path analysis. The results indicated a high correlation between dynamic arch height and static arch height (r=0.642), plantar fascia tension (r=-0.797), and maximum rearfoot eversion motion during gait (r=-0.518). The path analysis model without the direct rearfoot eversion effect explained 81.2% of the variance in plantar fascia tension, while the model with the direct rearfoot eversion effect explained 82.1% of the variance in plantar fascia tension. Including the indirect effect of maximum rearfoot eversion motion on plantar fascia tension through control of dynamic arch height is the model that best explains the interrelationships of these foot characteristics. The amount of maximum rearfoot eversion motion itself is not a good predictor of plantar fascia tension, however, together with the arch height, maximum rearfoot eversion motion is a good predictor because it has a pronounced indirect effect on plantar fascia tension. Copyright 2010. Published by Elsevier Ltd.

Can Chunk Size Differences Explain Developmental Changes in Lexical Learning?

PubMed Central

Smalle, Eleonore H. M.; Bogaerts, Louisa; Simonis, Morgane; Duyck, Wouter; Page, Michael P. A.; Edwards, Martin G.; Szmalec, Arnaud

2016-01-01

In three experiments, we investigated Hebb repetition learning (HRL) differences between children and adults, as a function of the type of item (lexical vs. sub-lexical) and the level of item-overlap between sequences. In a first experiment, it was shown that when non-repeating and repeating (Hebb) sequences of words were all permutations of the same words, HRL was slower than when the sequences shared no words. This item-overlap effect was observed in both children and adults. In a second experiment, we used syllable sequences and we observed reduced HRL due to item-overlap only in children. The findings are explained within a chunking account of the HRL effect on the basis of which we hypothesize that children, compared with adults, chunk syllable sequences in smaller units. By hypothesis, small chunks are more prone to interference from anagram representations included in the filler sequences, potentially explaining the item-overlap effect in children. This hypothesis was tested in a third experiment with adults where we experimentally manipulated the chunk size by embedding pauses in the syllable sequences. Interestingly, we showed that imposing a small chunk size caused adults to show the same behavioral effects as those observed in children. Departing from the analogy between verbal HRL and lexical development, the results are discussed in light of the less-is-more hypothesis of age-related differences in language acquisition. PMID:26779065

The Association between Physical Activity and Eating Self-Regulation in Overweight and Obese Women

PubMed Central

Carraça, Eliana V.; Silva, Marlene N.; Coutinho, Sílvia R.; Vieira, Paulo N.; Minderico, Cláudia S.; Sardinha, Luís B.; Teixeira, Pedro J.

2013-01-01

Objective Successful weight management relies heavily on eating and exercise behaviors. However, little is known about the association between both on a psychosocial level. This study examined the relationship between exercise and eating regulation by exploring the mediating effects of negative body image investment and depressive mood, and their stability through time. Methods Analyses were conducted at two different moments (12 and 36 months), involving a sample of 221 overweight/obese women (age: 37.6 ± 7 years; BMI: 31.6 ± 4.1 kg/m2) that participated in a behavioral weight control intervention. Bivariate correlations and mediation analyses using Preacher & Hayes resampling procedures were conducted. Results At 12 months, negative body image investment was the only significant mediator of the exercise-eating relationship. This variable explained larger portions of the indirect effects of structured rather than lifestyle exercise on eating. At 36 months, negative investment and to a lesser extent depressive mood partially explained the exercise-eating association. Conclusions Our findings suggest that, besides physiological effects of exercise, psychological mechanisms related to body image and mood also explain the role of physical activity as a ‘gateway behavior’ for improved eating regulation in overweight women. These effects appear to be stable and may help understand the key role of exercise in long-term weight management. PMID:24217426

On climate prediction: how much can we expect from climate memory?

NASA Astrophysics Data System (ADS)

Yuan, Naiming; Huang, Yan; Duan, Jianping; Zhu, Congwen; Xoplaki, Elena; Luterbacher, Jürg

2018-03-01

Slowing variability in climate system is an important source of climate predictability. However, it is still challenging for current dynamical models to fully capture the variability as well as its impacts on future climate. In this study, instead of simulating the internal multi-scale oscillations in dynamical models, we discussed the effects of internal variability in terms of climate memory. By decomposing climate state x(t) at a certain time point t into memory part M(t) and non-memory part ɛ (t) , climate memory effects from the past 30 years on climate prediction are quantified. For variables with strong climate memory, high variance (over 20% ) in x(t) is explained by the memory part M(t), and the effects of climate memory are non-negligible for most climate variables, but the precipitation. Regarding of multi-steps climate prediction, a power law decay of the explained variance was found, indicating long-lasting climate memory effects. The explained variances by climate memory can remain to be higher than 10% for more than 10 time steps. Accordingly, past climate conditions can affect both short (monthly) and long-term (interannual, decadal, or even multidecadal) climate predictions. With the memory part M(t) precisely calculated from Fractional Integral Statistical Model, one only needs to focus on the non-memory part ɛ (t) , which is an important quantity that determines climate predictive skills.

Neuroimaging explanations of age-related differences in task performance.

PubMed

Steffener, Jason; Barulli, Daniel; Habeck, Christian; Stern, Yaakov

2014-01-01

Advancing age affects both cognitive performance and functional brain activity and interpretation of these effects has led to a variety of conceptual research models without always explicitly linking the two effects. However, to best understand the multifaceted effects of advancing age, age differences in functional brain activity need to be explicitly tied to the cognitive task performance. This work hypothesized that age-related differences in task performance are partially explained by age-related differences in functional brain activity and formally tested these causal relationships. Functional MRI data was from groups of young and old adults engaged in an executive task-switching experiment. Analyses were voxel-wise testing of moderated-mediation and simple mediation statistical path models to determine whether age group, brain activity and their interaction explained task performance in regions demonstrating an effect of age group. Results identified brain regions whose age-related differences in functional brain activity significantly explained age-related differences in task performance. In all identified locations, significant moderated-mediation relationships resulted from increasing brain activity predicting worse (slower) task performance in older but not younger adults. Findings suggest that advancing age links task performance to the level of brain activity. The overall message of this work is that in order to understand the role of functional brain activity on cognitive performance, analysis methods should respect theoretical relationships. Namely, that age affects brain activity and brain activity is related to task performance.

How Changes in Psychosocial Job Characteristics Impact Burnout in Nurses: A Longitudinal Analysis.

PubMed

Pisanti, Renato; van der Doef, Margot; Maes, Stan; Meier, Laurenz Linus; Lazzari, David; Violani, Cristiano

2016-01-01

The main aim of this longitudinal study was to test the Job Demand-Control-Support (JDCS) model and to analyze whether changes in psychosocial job characteristics are related to (changes in) burnout. Previous studies on the effects of JDCS variables on burnout dimensions have indicated that the iso-strain hypothesis (i.e., high job demands, low control, and low support additively predict high stress reactions) and the buffer hypotheses (i.e., high job control and/or social support is expected to moderate the negative impact of high demands on stress reactions) have hardly been examined concurrently in a longitudinal design; and that the effects of changes of psychosocial job variables on burnout dimensions have hardly been analyzed. This two wave study was carried out over a period of 14 months in a sample of 217 Italian nurses. Hierarchical regression analyses were used to test the cross lagged main and interactive effects of JDCS variables, and to analyse the across-time effects of changes in JDCS dimensions on burnout variables. The Time 1 job characteristics explained 2-8% of the variance in the Time 2 burnout dimensions, but no support for the additive, or the buffer hypothesis of the JDCS model was found. Changes in job characteristics explained an additional 3-20% of variance in the Time 2 burnout dimensions. Specifically, high levels of emotional exhaustion at Time 2 were explained by high levels of social support at Time 1, and unfavorable changes in demands, control, and support over time; high depersonalization at Time 2 was explained by high social support at time 1 and by an increase in demands over time; and high personal accomplishment at Time 2 was predicted by high demands, high control, interactive effect demands × control × social support, at Time 1, and by a decrease in demands over time. No reversed effects of burnout on work characteristics have been found. Our findings suggest that the work environment is subject to changes: the majority of employees experienced considerable changes in all job conditions over time. These changes impacted employee burnout. Limitations and implications of the study are discussed.

Heavy metals in bullfrog (Rana catesbeiana) tadpoles: Effects of depuration before analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burger, J.; Snodgrass, J.

1998-11-01

Although tadpoles may well be excellent organisms to use as bioindicators of heavy metal contamination, the relationship of deposition in the body compared to the tail, and the effect of sediments or other debris in the digestive tract on heavy metal concentrations is unknown. The authors examined the effect of experimental depuration of bullfrog (Rana catesbeiana) tadpoles on heavy metal and selenium concentrations in intact tadpoles, as well as their bodies and tails. They defined depuration in this experiment as allowing defecation as an elimination process for intestinal contents. The authors maintained wild-caught tadpoles in clean water for 0, 24,more » 48, and 72 h to determine the effects of clearing on heavy metal concentrations. They also examined the concentrations of heavy metals in the whole body and digestive tract separately. The authors test the null hypotheses that no differences occur in metals as a function of time in uncontaminated water, and that no differences occur in metal concentrations in the body compared to the tail and to the digestive tract. They rejected these hypotheses based on regression models. Variance in concentrations of chromium (77%) and lead (70%) were explained by part and clearing time; for manganese (80%), mercury (64%), selenium (28%), and cadmium (25%) the variation was explained only by body part; for arsenic (53%), the variation was explained by part, clearing time, and weight of the various parts. For those metals in which clearing time explained part of the variation, metal concentrations in both the body and tail decreased after 24 and 48 h, but increased slightly thereafter. Clearing, however, did not greatly decrease metal concentrations in either the body or tail. These data suggest that for some metals (mercury, manganese, cadmium, selenium), clearing has no effect, and for others the effect is slight. For fresh tadpoles, however, the digestive tract contained significantly higher concentrations of all metals than either the body or head, probably reflecting metals absorbed to sediment particles in the gut.« less

How Changes in Psychosocial Job Characteristics Impact Burnout in Nurses: A Longitudinal Analysis

PubMed Central

Pisanti, Renato; van der Doef, Margot; Maes, Stan; Meier, Laurenz Linus; Lazzari, David; Violani, Cristiano

2016-01-01

Aims: The main aim of this longitudinal study was to test the Job Demand-Control-Support (JDCS) model and to analyze whether changes in psychosocial job characteristics are related to (changes in) burnout. Background: Previous studies on the effects of JDCS variables on burnout dimensions have indicated that the iso-strain hypothesis (i.e., high job demands, low control, and low support additively predict high stress reactions) and the buffer hypotheses (i.e., high job control and/or social support is expected to moderate the negative impact of high demands on stress reactions) have hardly been examined concurrently in a longitudinal design; and that the effects of changes of psychosocial job variables on burnout dimensions have hardly been analyzed. Design: This two wave study was carried out over a period of 14 months in a sample of 217 Italian nurses. Method: Hierarchical regression analyses were used to test the cross lagged main and interactive effects of JDCS variables, and to analyse the across-time effects of changes in JDCS dimensions on burnout variables. Results: The Time 1 job characteristics explained 2–8% of the variance in the Time 2 burnout dimensions, but no support for the additive, or the buffer hypothesis of the JDCS model was found. Changes in job characteristics explained an additional 3–20% of variance in the Time 2 burnout dimensions. Specifically, high levels of emotional exhaustion at Time 2 were explained by high levels of social support at Time 1, and unfavorable changes in demands, control, and support over time; high depersonalization at Time 2 was explained by high social support at time 1 and by an increase in demands over time; and high personal accomplishment at Time 2 was predicted by high demands, high control, interactive effect demands × control × social support, at Time 1, and by a decrease in demands over time. No reversed effects of burnout on work characteristics have been found. Conclusion: Our findings suggest that the work environment is subject to changes: the majority of employees experienced considerable changes in all job conditions over time. These changes impacted employee burnout. Limitations and implications of the study are discussed. PMID:27507952

Single-event effects experienced by astronauts and microelectronic circuits flown in space

DOE Office of Scientific and Technical Information (OSTI.GOV)

McNulty, P.J.

Models developed for explaining the light flashes experienced by astronauts on Apollo and Skylab missions were used with slight modification to explain upsets observed in microelectronic circuits. Both phenomena can be explained by the simple assumption that an event occurs whenever a threshold number of ionizations or isomerizations are generated within a sensitive volume. Evidence is consistent with the threshold being sharp in both cases, but fluctuations in the physical stimuli lead to a gradual rather than sharp increase in cross section with LET. Successful use of the model requires knowledge of the dimensions of the sensitive volume and themore » value of threshold. Techniques have been developed to determine these SEU parameters in modern circuits.« less

Genetic and Environmental Influences on Global Family Conflict

PubMed Central

Horwitz, Briana N.; Neiderhiser, Jenae M.; Ganiban, Jody M.; Spotts, Erica L.; Lichtenstein, Paul; Reiss, David

2010-01-01

This study examined genetic and environmental influences on global family conflict. The sample comprised 872 same-sex pairs of twin parents, their spouses/partners and one adolescent child per twin from the Twin and Offspring Study in Sweden (TOSS). The twins, spouses and child each reported on the degree of family conflict, and there was significant agreement among the family members’ ratings. These shared perspectives were explained by one common factor, indexing global family conflict. Genetic influences explained 36% of the variance in this common factor, suggesting that twins’ heritable characteristics contribute to family conflict, via genotype-environment correlation. Nonshared environmental effects explained the remaining 64% of this variance, indicating that twins’ unique childhood and/or current family experiences also play an important role. PMID:20438198

Makeup of the genetic correlation between milk production traits using genome-wide single nucleotide polymorphism information.

PubMed

van Binsbergen, R; Veerkamp, R F; Calus, M P L

2012-04-01

The correlated responses between traits may differ depending on the makeup of genetic covariances, and may differ from the predictions of polygenic covariances. Therefore, the objective of the present study was to investigate the makeup of the genetic covariances between the well-studied traits: milk yield, fat yield, protein yield, and their percentages in more detail. Phenotypic records of 1,737 heifers of research farms in 4 different countries were used after homogenizing and adjusting for management effects. All cows had a genotype for 37,590 single nucleotide polymorphisms (SNP). A bayesian stochastic search variable selection model was used to estimate the SNP effects for each trait. About 0.5 to 1.0% of the SNP had a significant effect on 1 or more traits; however, the SNP without a significant effect explained most of the genetic variances and covariances of the traits. Single nucleotide polymorphism correlations differed from the polygenic correlations, but only 10 regions were found with an effect on multiple traits; in 1 of these regions the DGAT1 gene was previously reported with an effect on multiple traits. This region explained up to 41% of the variances of 4 traits and explained a major part of the correlation between fat yield and fat percentage and contributes to asymmetry in correlated response between fat yield and fat percentage. Overall, for the traits in this study, the infinitesimal model is expected to be sufficient for the estimation of the variances and covariances. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Regional inequalities in child malnutrition in Egypt, Jordan, and Yemen: a Blinder-Oaxaca decomposition analysis.

PubMed

Sharaf, Mesbah Fathy; Rashad, Ahmed Shoukry

2016-12-01

There is substantial evidence that on average, urban children have better health outcomes than rural children. This paper investigates the underlying factors that account for the regional disparities in child malnutrition in three Arab countries, namely; Egypt, Jordan, and Yemen. We use data on a nationally representative sample from the most recent rounds of the Demographic and Health Survey. A Blinder-Oaxaca decomposition analysis is conducted to decompose the rural-urban differences in child nutrition outcomes into two components; one that is explained by regional differences in the level of the determinants (covariate effects), and another component that is explained by differences in the effect of the determinants on the child nutritional status (coefficient effects). Results show that the under-five stunting rates are 20 % in Egypt, 46.5 % in Yemen, and 7.7 % in Jordan. The rural- urban gap in child malnutrition was minor in the case of Egypt (2.3 %) and Jordan (1.5 %), while the regional gap was significant in the case of Yemen (17.7 %). Results of the Blinder-Oaxaca decomposition show that the covariate effect is dominant in the case of Yemen while the coefficients effect dominates in the case of Jordan. Income inequality between urban and rural households explains most of the malnutrition gap. Results were robust to the different decomposition weighting schemes. By identifying the underlying factors behind the rural- urban health disparities, the findings of this paper help in designing effective intervention measures aimed at reducing regional inequalities and improving population health outcomes.

Diverging temperature responses of CO2 assimilation and plant development explain the overall effect of temperature on biomass accumulation in wheat leaves and grains.

PubMed

Collins, Nicholas C; Parent, Boris

2017-01-09

There is a growing consensus in the literature that rising temperatures influence the rate of biomass accumulation by shortening the development of plant organs and the whole plant and by altering rates of respiration and photosynthesis. A model describing the net effects of these processes on biomass would be useful, but would need to reconcile reported differences in the effects of night and day temperature on plant productivity. In this study, the working hypothesis was that the temperature responses of CO 2 assimilation and plant development rates were divergent, and that their net effects could explain observed differences in biomass accumulation. In wheat (Triticum aestivum) plants, we followed the temperature responses of photosynthesis, respiration and leaf elongation, and confirmed that their responses diverged. We measured the amount of carbon assimilated per "unit of plant development" in each scenario and compared it to the biomass that accumulated in growing leaves and grains. Our results suggested that, up to a temperature optimum, the rate of any developmental process increased with temperature more rapidly than that of CO 2 assimilation and that this discrepancy, summarised by the CO 2 assimilation rate per unit of plant development, could explain the observed reductions in biomass accumulation in plant organs under high temperatures. The model described the effects of night and day temperature equally well, and offers a simple framework for describing the effects of temperature on plant growth. Published by Oxford University Press on behalf of the Annals of Botany Company.

JP-8 jet fuel exposure rapidly induces high levels of IL-10 and PGE2 secretion and is correlated with loss of immune function.

PubMed

Harris, David T; Sakiestewa, Debbie; Titone, Dominic; Witten, Mark

2007-05-01

The US Air Force has implemented the widespread use of JP-8 jet fuel in its operations, although a thorough understanding of its potential effects upon exposed personnel is unclear. Previous work has demonstrated that JP-8 exposure is immunosuppressive. In the present study, the potential mechanisms for the effects of JP-8 exposure on the immune system were investigated. Exposure of mice to JP-8 for 1 h/day resulted in immediate secretion of two immunosuppressive agents; namely, interleukin-10 (IL-10) and prostaglandin E2 (PGE2). JP-8 exposure rapidly induced a persistently high level of serum IL-10 and PGE2 at an exposure concentration of 1000 mg/m3. IL-10 levels peaked at 2 h post-JP-8 exposure and then stabilized at significantly elevated serum levels, while PGE2 levels peaked after 2-3 days of exposure and then stabilized. Elevated IL-10 and PGE2 levels may at least partially explain the effects of JP-8 exposure on immune function. Elevated IL-10 and PGE2 levels, however, cannot explain all of the effects due to JP-8 exposure (e.g., decreased organ weights and decreased viable immune cells), as treatment with a PGE2 inhibitor did not completely reverse the immunosuppressive effects of jet fuel exposure. Thus, low concentration JP-8 jet fuel exposures have significant effects on the immune system, which can be partially explained by the secretion of immunosuppressive modulators, which are cumulative over time.

The Extended Community-Level Effects of Genetic Variation in Foliar Wax Chemistry in the Forest Tree Eucalyptus globulus.

PubMed

Gosney, Benjamin; O'Reilly-Wapstra, Julianne; Forster, Lynne; Whiteley, Carmen; Potts, Brad

2017-05-01

Genetic variation in foundation trees can influence dependent communities, but little is known about the mechanisms driving these extended genetic effects. We studied the potential chemical drivers of genetic variation in the dependent foliar community of the focal tree Eucalyptus globulus. We focus on the role of cuticular waxes and compare the effects to that of the terpenes, a well-studied group of secondary compounds known to be bioactive in eucalypts. The canopy community was quantified based on the abundance of thirty-nine distinctive arthropod and fungal symptoms on foliar samples collected from canopies of 246 progeny from 13 E. globulus sub-races grown in a common garden trial. Cuticular waxes and foliar terpenes were quantified using gas chromatography - mass spectrometry (GC-MC). A total of 4 of the 13 quantified waxes and 7 of the 16 quantified terpenes were significantly associated with the dependent foliar community. Variation in waxes explained 22.9% of the community variation among sub-races, which was equivalent to that explained by terpenes. In combination, waxes and terpenes explained 35% of the genetic variation among sub-races. Only a small proportion of wax and terpene compounds showing statistically significant differences among sub-races were implicated in community level effects. The few significant waxes have previously shown evidence of divergent selection in E. globulus, which signals that adaptive variation in phenotypic traits may have extended effects. While highlighting the role of the understudied cuticular waxes, this study demonstrates the complexity of factors likely to lead to community genetic effects in foundation trees.

The relationship between observational scale and explained variance in benthic communities

PubMed Central

Flood, Roger D.; Frisk, Michael G.; Garza, Corey D.; Lopez, Glenn R.; Maher, Nicole P.

2018-01-01

This study addresses the impact of spatial scale on explaining variance in benthic communities. In particular, the analysis estimated the fraction of community variation that occurred at a spatial scale smaller than the sampling interval (i.e., the geographic distance between samples). This estimate is important because it sets a limit on the amount of community variation that can be explained based on the spatial configuration of a study area and sampling design. Six benthic data sets were examined that consisted of faunal abundances, common environmental variables (water depth, grain size, and surficial percent cover), and sonar backscatter treated as a habitat proxy (categorical acoustic provinces). Redundancy analysis was coupled with spatial variograms generated by multiscale ordination to quantify the explained and residual variance at different spatial scales and within and between acoustic provinces. The amount of community variation below the sampling interval of the surveys (< 100 m) was estimated to be 36–59% of the total. Once adjusted for this small-scale variation, > 71% of the remaining variance was explained by the environmental and province variables. Furthermore, these variables effectively explained the spatial structure present in the infaunal community. Overall, no scale problems remained to compromise inferences, and unexplained infaunal community variation had no apparent spatial structure within the observational scale of the surveys (> 100 m), although small-scale gradients (< 100 m) below the observational scale may be present. PMID:29324746

Effects of recruitment, growth, and exploitation on walleye population size structure in northern Wisconsin lakes

USGS Publications Warehouse

Hansen, Michael J.; Nate, Nancy A.

2014-01-01

We evaluated the dynamics of walleye Sander vitreus population size structure, as indexed by the proportional size distribution (PSD) of quality-length fish, in Escanaba Lake during 1967–2003 and in 204 other lakes in northern Wisconsin during 1990–2011. We estimated PSD from angler-caught walleyes in Escanaba Lake and from spring electrofishing in 204 other lakes, and then related PSD to annual estimates of recruitment to age-3, length at age 3, and annual angling exploitation rate. In Escanaba Lake during 1967–2003, annual estimates of PSD were highly dynamic, growth (positively) explained 35% of PSD variation, recruitment explained only 3% of PSD variation, and exploitation explained only 7% of PSD variation. In 204 other northern Wisconsin lakes during 1990–2011, PSD varied widely among lakes, recruitment (negatively) explained 29% of PSD variation, growth (positively) explained 21% of PSD variation, and exploitation explained only 4% of PSD variation. We conclude that population size structure was most strongly driven by recruitment and growth, rather than exploitation, in northern Wisconsin walleye populations. Studies of other species over wide spatial and temporal ranges of recruitment, growth, and mortality are needed to determine which dynamic rate most strongly influences population size structure of other species. Our findings indicate a need to be cautious about assuming exploitation is a strong driver of walleye population size structure.

Knowledge Based Synthesis of Efficient Structures for Concurrent Computation Using Fat-Trees and Pipelining.

DTIC Science & Technology

1986-12-31

synthesize synchronization skeletons"Science of Computer Programming 2, 1982, pp. 241-266 [Gel85] Gelernter, David, "Generative communication in...effective computation based on given primitives . An architecture is an abstract object-type, whose instances are computing systems. By a parallel computing...explaining the language primitives on this basis. We explain how such a basis can be "simpler" than a general-purpose manual-programming language such as

Cyber Warfare as an Operational Fire

DTIC Science & Technology

2010-04-03

This paper explores cyber warfare as an option for creating operational fires effects. Initially, cyberspace is defined and explained from the...fires are defined and the advantages of their use are explained. From there, discussion focuses on how cyber warfare fulfills the purposes of...operational fires. Finally, the paper draws conclusions about the viability of cyber warfare as an operational fire and makes recommendations about how to prioritize the activities of the newly approved U.S. Cyber Command.

The relationship between particulate pollution levels in Australian cities, meteorology, and landscape fire activity detected from MODIS hotspots.

PubMed

Price, Owen F; Williamson, Grant J; Henderson, Sarah B; Johnston, Fay; Bowman, David M J S

2012-01-01

Smoke from bushfires is an emerging issue for fire managers because of increasing evidence for its public health effects. Development of forecasting models to predict future pollution levels based on the relationship between bushfire activity and current pollution levels would be a useful management tool. As a first step, we use daily thermal anomalies detected by the MODIS Active Fire Product (referred to as "hotspots"), pollution concentrations, and meteorological data for the years 2002 to 2008, to examine the statistical relationship between fire activity in the landscapes and pollution levels around Perth and Sydney, two large Australian cities. Resultant models were statistically significant, but differed in their goodness of fit and the distance at which the strength of the relationship was strongest. For Sydney, a univariate model for hotspot activity within 100 km explained 24% of variation in pollution levels, and the best model including atmospheric variables explained 56% of variation. For Perth, the best radius was 400 km, explaining only 7% of variation, while the model including atmospheric variables explained 31% of the variation. Pollution was higher when the atmosphere was more stable and in the presence of on-shore winds, whereas there was no effect of wind blowing from the fires toward the pollution monitors. Our analysis shows there is a good prospect for developing region-specific forecasting tools combining hotspot fire activity with meteorological data.

Theories of Suggestion.

PubMed

Brown, W

1928-02-01

The word "suggestion" has been used in educational, scientific and medical literature in slightly different senses. In psychological medicine the use of suggestion has developed out of the earlier use of hypnotic influence.Charcot defined hypnosis as an artificial hysteria, Bernheim as an artificially increased suggestibility. The two definitions need to be combined to give an adequate account of hypnosis. Moreover, due allowance should be made for the factors of dissociation and of rapport in hypnotic phenomena.The relationships between dissociation, suggestibility, and hypnotizability.Theories of suggestion propounded by Pierre Janet, Freud, McDougall, Pawlow and others. Ernest Jones's theory of the nature of auto-suggestion. Janet explains suggestion in terms of ideo-motor action in which the suggested idea, because of the inactivity of competing ideas, produces its maximum effect. Freud explains rapport in terms of the sex instinct "inhibited in its aim" (transference) and brings in his distinction of "ego" and "ego-ideal" (or "super-ego") to supplement the theory. Jones explains auto-suggestion in terms of narcissism. McDougall explains hypnotic suggestion in terms of the instinct of self-abasement. But different instincts may supply the driving power to produce suggestion-effects in different circumstances. Such instincts as those of self-preservation (fear) and gregariousness may play their part. Auto-suggestion as a therapeutic factor is badly named. It supplements, but does not supplant the will, and makes complete volition possible.

The contribution of spray formulation component variables to foliar uptake of agrichemicals.

PubMed

Forster, W Alison; Kimberley, Mark O

2015-09-01

The objective of the present study was to determine the contribution of the active ingredient (AI) and surfactant, and their concentrations, to the foliar uptake of agrichemicals, and to examine the physical properties that would need to be included in a model for foliar uptake. All spray formulation component variables significantly affected uptake, explaining 73% of the deviance. The deviance explained by each factor ranged from 43% (AI concentration nested within AI) to 5.6% (surfactant). The only significant interaction was between AI and surfactant, explaining 15.8% of the deviance. Overall, 90% of the deviance could be explained by the variables and their first-order interactions. Uptake increased with increasing lipophilicity of the AI at concentrations below those causing precipitation on the leaf surface. AI concentration had a far greater (negative) effect on the uptake of the lipophilic molecule epoxiconazole. The uptake of 2-deoxy-D-glucose (DOG) and 2,4-dichlorophenoxyacetic acid (2,4-D) increased with increasing hydrophile-lipophile balance (HLB) of the surfactant, the effect of HLB being far greater on the hydrophilic molecule DOG. However, the differences observed in epoxiconazole uptake owing to the surfactant were strongly positively related to the spread area of the formulation on the leaf surface. For all AIs, uptake increased in a similar manner with increasing molar surfactant concentration. © 2014 Society of Chemical Industry.

Theories of Suggestion

PubMed Central

Brown, William

1928-01-01

The word “suggestion” has been used in educational, scientific and medical literature in slightly different senses. In psychological medicine the use of suggestion has developed out of the earlier use of hypnotic influence. Charcot defined hypnosis as an artificial hysteria, Bernheim as an artificially increased suggestibility. The two definitions need to be combined to give an adequate account of hypnosis. Moreover, due allowance should be made for the factors of dissociation and of rapport in hypnotic phenomena. The relationships between dissociation, suggestibility, and hypnotizability. Theories of suggestion propounded by Pierre Janet, Freud, McDougall, Pawlow and others. Ernest Jones's theory of the nature of auto-suggestion. Janet explains suggestion in terms of ideo-motor action in which the suggested idea, because of the inactivity of competing ideas, produces its maximum effect. Freud explains rapport in terms of the sex instinct “inhibited in its aim” (transference) and brings in his distinction of “ego” and “ego-ideal” (or “super-ego”) to supplement the theory. Jones explains auto-suggestion in terms of narcissism. McDougall explains hypnotic suggestion in terms of the instinct of self-abasement. But different instincts may supply the driving power to produce suggestion-effects in different circumstances. Such instincts as those of self-preservation (fear) and gregariousness may play their part. Auto-suggestion as a therapeutic factor is badly named. It supplements, but does not supplant the will, and makes complete volition possible. PMID:19986306

The influence of landscape features on road development in a loess region, China.

PubMed

Bi, Xiaoli; Wang, Hui; Zhou, Rui

2011-10-01

Many ecologists focus on the effects of roads on landscapes, yet few consider how landscapes affect road systems. In this study, therefore, we quantitatively evaluated how land cover, topography, and building density affected the length density, node density, spatial pattern, and location of roads in Dongzhi Yuan, a typical loess region in China. Landscape factors and roads were mapped using images from SPOT satellite (Système Probatoire d'Observation de la Terre), initiated by the French space agency and a digital elevation model (DEM). Detrended canonical correspondence analysis (DCCA), a useful ordination technique to explain species-environment relations in community ecology, was applied to evaluate the ways in which landscapes may influence roads. The results showed that both farmland area and building density were positively correlated with road variables, whereas gully density and the coefficient of variation (CV of DEM) showed negative correlations. The CV of DEM, farmland area, grassland area, and building density explained variation in node density, length density, and the spatial pattern of roads, whereas gully density and building density explained variation in variables representing road location. In addition, node density, rather than length density, was the primary road variable affected by landscape variables. The results showed that the DCCA was effective in explaining road-landscape relations. Understanding these relations can provide information for landscape managers and transportation planners.

Drug 'hot-spots', alcohol availability and violence.

PubMed

Gorman, D M; Zhu, Li; Horel, Scott

2005-11-01

Ecological studies have shown a relationship between alcohol outlet densities and violence and between the location of crimes related to illicit drug use (so-called 'hot spots') and violence. To date, no study has compared the effects of alcohol outlets and drug hot spots on rates of violence. The present study examined this relationship in the City of Houston, Texas. An ecological study design was employed, using a sample of 439 census tracts from Houston, Texas. Neighborhood socio-structural, alcohol outlet density, drug crime density and violent crime density data were collected from archival sources and analyzed using multivariate and spatial statistics. Using ordinary least-squares analysis, the neighborhood socio-structural covariates explained about 40% of the variability in violent crime. Adding alcohol outlet density in the target census tracts explained an additional 6%, while the addition of drug crime density explained an additional 32%. In the final model, that controlled for the effects of autocorrelated error, both drug crime density in the target and adjacent census tracts remained significant predictors of violent crime, while only off-sale density in the target census tract remained significant in the model. The findings indicate that drug crime density explained a greater amount of variance in violent crime rates than the alcohol outlet density. The methodological and policy implications of these findings are discussed, along with the shortcomings of the analysis presented.

Process model simulations of the divergence effect

NASA Astrophysics Data System (ADS)

Anchukaitis, K. J.; Evans, M. N.; D'Arrigo, R. D.; Smerdon, J. E.; Hughes, M. K.; Kaplan, A.; Vaganov, E. A.

2007-12-01

We explore the extent to which the Vaganov-Shashkin (VS) model of conifer tree-ring formation can explain evidence for changing relationships between climate and tree growth over recent decades. The VS model is driven by daily environmental forcing (temperature, soil moisture, and solar radiation), and simulates tree-ring growth cell-by-cell as a function of the most limiting environmental control. This simplified representation of tree physiology allows us to examine using a selection of case studies whether instances of divergence may be explained in terms of changes in limiting environmental dependencies or transient climate change. Identification of model-data differences permits further exploration of the effects of tree-ring standardization, atmospheric composition, and additional non-climatic factors.

Can a microscopic stochastic model explain the emergence of pain cycles in patients?

NASA Astrophysics Data System (ADS)

Di Patti, Francesca; Fanelli, Duccio

2009-01-01

A stochastic model is introduced here to investigate the molecular mechanisms which trigger the perception of pain. The action of analgesic drug compounds is discussed in a dynamical context, where the competition with inactive species is explicitly accounted for. Finite size effects inevitably perturb the mean-field dynamics: oscillations in the amount of bound receptors are spontaneously manifested, driven by the noise which is intrinsic to the system under scrutiny. These effects are investigated both numerically, via stochastic simulations, and analytically, through a large size expansion. The claim that our findings could provide a consistent interpretative framework for explaining the emergence of cyclic behaviors in response to analgesic treatments is substantiated.

Toxin-Based Drug May Be New Option for Rare Leukemia

Cancer.gov

In patients with hairy cell leukemia, the toxin-based treatment moxetumomab pasudotox may be an effective new treatment option. As this Cancer Currents post explains, the drug looked to be highly effective in a large clinical trial.

Construction Management: Planning Ahead.

ERIC Educational Resources Information Center

Arsht, Steven

2003-01-01

Explains that preconstruction planning is essential when undertaking the challenges of a school building renovation or expansion, focusing on developing a detailed estimate, creating an effective construction strategy, conducting reviews and value-engineering workshops, and realizing savings through effective risk analysis and contingency…

Disruption of iron homeostasis in mesothelial cells following talc pleurodesis

EPA Science Inventory

The mechanism for biological effect following particle exposure is incompletely understood. One postulate proposed to explain biological effect after particles is an altered iron homeostasis in the host. The fibro-inflammatory properties of particles are exploited therapeutically...

Teaching children with autism to explain how: A case for problem solving?

PubMed

Frampton, Sarah E; Alice Shillingsburg, M

2018-04-01

Few studies have applied Skinner's (1953) conceptualization of problem solving to teach socially significant behaviors to individuals with developmental disabilities. The current study used a multiple probe design across behavior (sets) to evaluate the effects of problem-solving strategy training (PSST) on the target behavior of explaining how to complete familiar activities. During baseline, none of the three participants with autism spectrum disorder (ASD) could respond to the problems presented to them (i.e., explain how to do the activities). Tact training of the actions in each activity alone was ineffective; however, all participants demonstrated independent explaining-how following PSST. Further, following PSST with Set 1, tact training alone was sufficient for at least one scenario in sets 2 and 3 for all 3 participants. Results have implications for generative responding for individuals with ASD and further the discussion regarding the role of problem solving in complex verbal behavior. © 2018 Society for the Experimental Analysis of Behavior.

Ancient fluvial processes in the equatorial highlands of Mars

NASA Technical Reports Server (NTRS)

Craddock, Robert A.; Maxwell, Ted A.

1991-01-01

Martian highland craters typically lack ejecta deposits, have no noticeable rim, and are flat floored. In addition, crater size frequency distribution curves show that highland craters have depleted populations less than 20 km in diameter. A variety of processes have been suggested to explain these observations including deposition of aeolian or volcanic materials up to the crater rim crests, thermal creep, terrain softening, and mass wasting. However, none of these processes adequately explains both the crater morphology and population distribution. In order to explain both the Martian highland crater morphology and population distribution, a fluvial process is proposed which is capable of removing the loose crater rim material. The resulting effect is to decrease the crater diameter, thereby causing the population curves to bendover. The eroded material is redistributed, burying or partially burying smaller diameter craters before complete erosion. This material may also be deposited into local topographic lows, creating the depositional basins observed. A fluvial process explains both sets of observations: crater morphology and crater population distribution curves.

Explaining the Gender Wealth Gap

PubMed Central

Ruel, Erin; Hauser, Robert M.

2013-01-01

To assess and explain the United States’ gender wealth gap, we use the Wisconsin Longitudinal Study to examine wealth accumulated by a single cohort over 50 years by gender, by marital status, and limited to the respondents who are their family’s best financial reporters. We find large gender wealth gaps between currently married men and women, and never-married men and women. The never-married accumulate less wealth than the currently married, and there is a marital disruption cost to wealth accumulation. The status-attainment model shows the most power in explaining gender wealth gaps between these groups explaining about one-third to one-half of the gap, followed by the human-capital explanation. In other words, a lifetime of lower earnings for women translates into greatly reduced wealth accumulation. A gender wealth gap remains between married men and women after controlling for the full model that we speculate may be related to gender differences in investment strategies and selection effects. PMID:23264038

Marriage, Work, and Racial Inequalities in Poverty: Evidence from the U.S.

PubMed

Thiede, Brian; Kim, Hyojung; Slack, Tim

2017-10-01

This paper explores recent racial and ethnic inequalities in poverty, estimating the share of racial poverty differentials that can be explained by variation in family structure and workforce participation. The authors use logistic regression to estimate the association between poverty and race, family structure, and workforce participation. They then decompose between-race differences in poverty risk to quantify how racial disparities in marriage and work explain observed inequalities in the log odds of poverty. They estimate that 47.7-48.9% of black-white differences in poverty risk can be explained by between-group variance in these two factors, while only 4.3-4.5% of the Hispanic-white differential in poverty risk can be explained by these variables. These findings underscore the continued association between racial disparities in poverty and those in labor and marriage markets. However, clear racial differences in the origin of poverty suggest that family- and worked-related policy interventions will not have uniformly effective or evenly distributed impacts on poverty reduction.

Metacommunity composition of web-spiders in a fragmented neotropical forest: relative importance of environmental and spatial effects.

PubMed

Baldissera, Ronei; Rodrigues, Everton N L; Hartz, Sandra M

2012-01-01

The distribution of beta diversity is shaped by factors linked to environmental and spatial control. The relative importance of both processes in structuring spider metacommunities has not yet been investigated in the Atlantic Forest. The variance explained by purely environmental, spatially structured environmental, and purely spatial components was compared for a metacommunity of web spiders. The study was carried out in 16 patches of Atlantic Forest in southern Brazil. Field work was done in one landscape mosaic representing a slight gradient of urbanization. Environmental variables encompassed plot- and patch-level measurements and a climatic matrix, while principal coordinates of neighbor matrices (PCNMs) acted as spatial variables. A forward selection procedure was carried out to select environmental and spatial variables influencing web-spider beta diversity. Variation partitioning was used to estimate the contribution of pure environmental and pure spatial effects and their shared influence on beta-diversity patterns, and to estimate the relative importance of selected environmental variables. Three environmental variables (bush density, land use in the surroundings of patches, and shape of patches) and two spatial variables were selected by forward selection procedures. Variation partitioning revealed that 15% of the variation of beta diversity was explained by a combination of environmental and PCNM variables. Most of this variation (12%) corresponded to pure environmental and spatially environmental structure. The data indicated that (1) spatial legacy was not important in explaining the web-spider beta diversity; (2) environmental predictors explained a significant portion of the variation in web-spider composition; (3) one-third of environmental variation was due to a spatial structure that jointly explains variation in species distributions. We were able to detect important factors related to matrix management influencing the web-spider beta-diversity patterns, which are probably linked to historical deforestation events.

Effect of improved fitness beyond weight loss on cardiovascular risk factors in individuals with type 2 diabetes in the Look AHEAD study.

PubMed

Gibbs, Bethany Barone; Brancati, Frederick L; Chen, Haiying; Coday, Mace; Jakicic, John M; Lewis, Cora E; Stewart, Kerry J; Clark, Jeanne M

2014-05-01

Because lifestyle-induced improvements in cardiovascular risk factors vary substantially across individuals with type 2 diabetes, we investigated the extent to which increases in fitness explain cardiovascular risk factor improvements independent of weight loss in a lifestyle intervention. We studied 1-year changes in Look AHEAD, a randomized trial comparing an intensive lifestyle intervention (ILI) to a diabetes support and education (DSE) control group in adults with type 2 diabetes. Assessments included weight, fitness, blood pressure (BP), glucose, HbA1c, and lipids. We evaluated the effects of changes in weight and fitness on changes in cardiovascular risk factors by study arm, using R (2) from multiple linear regression. Analyses included participants with fitness data at baseline and 1-year (n = 4408; 41% male, 36% non-white; mean age 58.7 ± 6.8 years). Weight change alone improved R (2) for explaining changes in risk factors up to 8.2% in ILI and 1.7% in DSE. Fitness change alone improved R (2) up to 3.9% in ILI and 0.8% in DSE. After adjusting for weight change, fitness was independently associated (p < 0.05) with improvements in R (2) for glucose (+0.7%), HbA1c (+1.1%), high-density lipoprotein (HDL) cholesterol (+0.4%), and triglycerides (+0.2%) in ILI and diastolic BP (+0.3%), glucose (+0.3%), HbA1c (+0.4%), and triglycerides (+0.1%) in DSE. Taken together, weight and fitness changes explained from 0.1-9.3% of the variability in cardiovascular risk factor changes. Increased fitness explained statistically significant but small improvements in several cardiovascular risk factors beyond weight loss. Further research identifying other factors that explain cardiovascular risk factor change is needed.

The Effects of Teacher Self-Disclosure via "Facebook" on Teacher Credibility

ERIC Educational Resources Information Center

Mazer, Joseph P.; Murphy, Richard E.; Simonds, Cheri J.

2009-01-01

Research suggests that teachers who personalize their teaching through the use of humor, stories, enthusiasm, and self-disclosure are perceived by their students to be effective in explaining course content. This experimental study examined the effects of computer-mediated teacher self-disclosure on perceptions of teacher credibility. Participants…

A Quantum Theoretical Explanation for Probability Judgment Errors

ERIC Educational Resources Information Center

Busemeyer, Jerome R.; Pothos, Emmanuel M.; Franco, Riccardo; Trueblood, Jennifer S.

2011-01-01

A quantum probability model is introduced and used to explain human probability judgment errors including the conjunction and disjunction fallacies, averaging effects, unpacking effects, and order effects on inference. On the one hand, quantum theory is similar to other categorization and memory models of cognition in that it relies on vector…

Importance of Effective Listening Infomercial

ERIC Educational Resources Information Center

Johnson-Curiskis, Nanette

2009-01-01

This article details an activity intended for use in a course with a unit on effective listening, including listening courses, public speaking, and interpersonal communication. Students will explain the importance of effective and active listening for a target audience by producing an infomercial for a product or service which they design.

The Family Dynamics of Intellectual Development.

ERIC Educational Resources Information Center

Zajonc, R. B.

2001-01-01

Birth order effects on intellectual performance show both positive and negative results. Considers the intellectual aspects of siblings' changing environments, explaining that birth order and family size effects depend crucially on the age at which children are tested. Within-family data conceal patterns of aggregate effects that are revealed by…

Genetic Architecture of Nest Building in Mice LG/J × SM/J

PubMed Central

Sauce, Bruno; de Brito, Reinaldo Alves; Peripato, Andrea Cristina

2012-01-01

Maternal care is critical to offspring growth and survival, which is greatly improved by building an effective nest. Some suggest that genetic variation and underlying genetic effects differ between fitness-related traits and other phenotypes. We investigated the genetic architecture of a fitness-related trait, nest building, in F2 female mice intercrossed from inbred strains SM/J and LG/J using a QTL analysis for six related nest phenotypes (Presence and Structure pre- and postpartum, prepartum Material Used and postpartum Temperature). We found 15 direct-effect QTLs explaining from 4 to 13% of the phenotypic variation in nest building, mostly with non-additive effect. Epistatic analyses revealed 71 significant epistatic interactions which together explain from 28.4 to 75.5% of the variation, indicating an important role for epistasis in the adaptive process of nest building behavior in mice. Our results suggest a genetic architecture with small direct effects and a larger number of epistatic interactions as expected for fitness-related phenotypes. PMID:22654894

How does cognitive dissonance influence the sunk cost effect?

PubMed

Chung, Shao-Hsi; Cheng, Kuo-Chih

2018-01-01

The sunk cost effect is the scenario when individuals are willing to continue to invest capital in a failing project. The purpose of this study was to explain such irrational behavior by exploring how sunk costs affect individuals' willingness to continue investing in an unfavorable project and to understand the role of cognitive dissonance on the sunk cost effect. This study used an experimental questionnaire survey on managers of firms listed on the Taiwan Stock Exchange and Over-The-Counter. The empirical results show that cognitive dissonance does not mediate the relationship between sunk costs and willingness to continue an unfavorable investment project. However, cognitive dissonance has a moderating effect, and only when the level of cognitive dissonance is high does the sunk cost have significantly positive impacts on willingness to continue on with an unfavorable investment. This study offers psychological mechanisms to explain the sunk cost effect based on the theory of cognitive dissonance, and it also provides some recommendations for corporate management.

How does cognitive dissonance influence the sunk cost effect?

PubMed Central

Chung, Shao-Hsi; Cheng, Kuo-Chih

2018-01-01

Background The sunk cost effect is the scenario when individuals are willing to continue to invest capital in a failing project. The purpose of this study was to explain such irrational behavior by exploring how sunk costs affect individuals’ willingness to continue investing in an unfavorable project and to understand the role of cognitive dissonance on the sunk cost effect. Methods This study used an experimental questionnaire survey on managers of firms listed on the Taiwan Stock Exchange and Over-The-Counter. Results The empirical results show that cognitive dissonance does not mediate the relationship between sunk costs and willingness to continue an unfavorable investment project. However, cognitive dissonance has a moderating effect, and only when the level of cognitive dissonance is high does the sunk cost have significantly positive impacts on willingness to continue on with an unfavorable investment. Conclusion This study offers psychological mechanisms to explain the sunk cost effect based on the theory of cognitive dissonance, and it also provides some recommendations for corporate management. PMID:29535561

Discrete Emotion Effects on Lexical Decision Response Times

PubMed Central

Briesemeister, Benny B.; Kuchinke, Lars; Jacobs, Arthur M.

2011-01-01

Our knowledge about affective processes, especially concerning effects on cognitive demands like word processing, is increasing steadily. Several studies consistently document valence and arousal effects, and although there is some debate on possible interactions and different notions of valence, broad agreement on a two dimensional model of affective space has been achieved. Alternative models like the discrete emotion theory have received little interest in word recognition research so far. Using backward elimination and multiple regression analyses, we show that five discrete emotions (i.e., happiness, disgust, fear, anger and sadness) explain as much variance as two published dimensional models assuming continuous or categorical valence, with the variables happiness, disgust and fear significantly contributing to this account. Moreover, these effects even persist in an experiment with discrete emotion conditions when the stimuli are controlled for emotional valence and arousal levels. We interpret this result as evidence for discrete emotion effects in visual word recognition that cannot be explained by the two dimensional affective space account. PMID:21887307

Discrete emotion effects on lexical decision response times.

PubMed

Briesemeister, Benny B; Kuchinke, Lars; Jacobs, Arthur M

2011-01-01

Our knowledge about affective processes, especially concerning effects on cognitive demands like word processing, is increasing steadily. Several studies consistently document valence and arousal effects, and although there is some debate on possible interactions and different notions of valence, broad agreement on a two dimensional model of affective space has been achieved. Alternative models like the discrete emotion theory have received little interest in word recognition research so far. Using backward elimination and multiple regression analyses, we show that five discrete emotions (i.e., happiness, disgust, fear, anger and sadness) explain as much variance as two published dimensional models assuming continuous or categorical valence, with the variables happiness, disgust and fear significantly contributing to this account. Moreover, these effects even persist in an experiment with discrete emotion conditions when the stimuli are controlled for emotional valence and arousal levels. We interpret this result as evidence for discrete emotion effects in visual word recognition that cannot be explained by the two dimensional affective space account.

Numerical and Experimental Investigations of Humping Phenomena in Laser Micro Welding

NASA Astrophysics Data System (ADS)

Otto, Andreas; Patschger, Andreas; Seiler, Michael

The Humping effect is a phenomenon which is observed approximately since 50 years in various welding procedures and is characterized by droplets due to a pile-up of the melt pool. It occurs within a broad range of process parameters. Particularly during micro welding, humping effect is critical due to typically high feed rates. In the past, essentially two approaches (fluid-dynamic approach of streaming melt within the molten pool and the Plateau-Rayleigh instability of a liquid jet) were discussed in order to explain the occurrence of the humping effect. But none of both can fully explain all observed effects. For this reason, experimental studies in micro welding of thin metal foils were performed in order to determine the influence of process parameters on the occurrence of humping effects. The experimental observations were compared with results from numerical multi-physical simulations (incorporating beam propagation, incoupling, heat transfer, fluid dynamics etc.) to provide a deeper understanding of the causes for hump formation.

Can the Knobe Effect Be Explained Away? Methodological Controversies in the Study of the Relationship Between Intentionality and Morality.

PubMed

Cova, Florian; Lantian, Anthony; Boudesseul, Jordane

2016-10-01

Based on the "Knobe Effect," Knobe has argued that moral evaluations can influence intentionality judgments. However, two methodological objections have been raised against this claim: first, that participants' answers do not accurately reflect what they think and, second, that the Knobe Effect can be fully explained by non-moral factors, such as the agent's desires or beliefs. In this article, we discuss these two methodological objections to the existence of the Knobe Effect and provide new evidence that moral evaluations can shape intentionality judgments. First, Study 1 shows that standard measures of intentionality do not overestimate participants' intentionality judgments. Second, Studies 2 and 3 suggest that participants' moral evaluations still mediate the impact of positive versus negative side-effects on judgments about intentional action, even when taking into account a whole range of non-moral factors. Results suggest that moral evaluations play an irreducible role in shaping our judgments about intentional action. © 2016 by the Society for Personality and Social Psychology, Inc.

Longitudinal Proximity Effect, Lateral Inverse Proximity Effect, and Nonequilibrium Superconductivity in Transition-edge Sensors

NASA Technical Reports Server (NTRS)

Sadleir, John E.

2010-01-01

We have recently shown that normal-metal/superconductor (N/S) bilayer TESs (superconducting Transition-Edge Sensors) exhibit weak-link behavior. Our measurements were explained in terms of a longitudinal proximity effect model in which superconducting order from the higher transition temperature leads is induced into the TES bilayer plane over remarkably long distances (up to 290 micron). Here we extend our understanding to include TESs with added noise-mitigating normal-metal structures (N structures). We explain our results of an effect converse to the longitudinal proximity effect (LoPE), the lateral inverse proximity effect (LaiPE), for which the order parameter in the N/S bilayer is reduced due to the neighboring N structures. We present resistance and critical current measurements as a function of temperature and magnetic field taken on square Mo/Au bilayer TESs with lengths ranging from 8 to 130 micron with and without added N structures. We observe the inverse proximity effect on the bilayer over in-plane distances many tens of microns and find the transition shifts to lower temperature scale approximately as the inverse square of the in-plane N-structure separation distance, without appreciable broadening of the transition width. We find TESs with added Au structures exhibit weak-link behavior as evidenced by exponential temperature dependence of the critical current and Josephson-like oscillations of the critical current with applied magnetic field. We also present evidence for nonequilbrium superconductivity and estimate a quasiparticle lifetime of 1.8 x 10(exp -10) s for the bilayer. The LoPE model is also used to explain the increased conductivity at temperatures above the bilayer's steep resistive transition

Process strengths determine the forms of the relationship between plant species richness and primary productivity

PubMed Central

Wang, Zhenhong

2017-01-01

The current rates of biodiversity loss have exceeded the rates observed during the earth’s major extinction events, which spurs the studies of the ecological relationships between biodiversity and ecosystem functions, stability, and services to determine the consequences of biodiversity loss. Plant species richness-productivity relationship (SRPR) is crucial to the understanding of these relationships in plants. Most ecologists have reached a widespread consensus that the loss of plant diversity undoubtedly impairs ecosystem functions, and have proposed many processes to explain the SRPR. However, none of the available studies has satisfactorily described the forms and mechanisms clarifying the SRPR. Observed results of the SRPR forms are inconsistent, and studies have long debated the ecological processes explaining the SRPR. Here, I have developed a simple model that combines the positive and/or negative effects of sixteen ecological processes on the SRPR and models that describe the dynamics of complementary-selection effect, density effect, and the interspecific competitive stress influenced by other ecological processes. I can regulate the strengths of the effects of these ecological processes to derive the asymptotic, positive, humped, negative, and irregular forms of the SRPR, and verify these forms using the observed data. The results demonstrated that the different strengths of the ecological processes determine the forms of the SRPR. The forms of the SRPR can change with variations in the strengths of the ecological processes. The dynamic characteristics of the complementary-selection effect, density effect, and the interspecific competitive stress on the SRPR are diverse, and are dependent on the strengths and variation of the ecological processes. This report explains the diverse forms of the SRPR, clarifies the integrative effects of the different ecological processes on the SRPR, and deepens our understanding of the interactions that occur among these ecological processes. PMID:29140995

Cost-effectiveness analysis: role and implications.

PubMed

Marsden, G; Wonderling, D

2013-03-01

Cost-effectiveness analysis (CEA) is often misperceived to be a cost-cutting exercise. The intention of CEA is not to identify and implement cheap technologies, but rather those which offer maximum health gain, subject to available funds. Such analysis is crucial for decision making in health care, as tight budget constraints mean spending in one area of healthcare displaces spending elsewhere. Therefore in order to achieve the greatest health gain for the overall population, treatments must be selected which provide the greatest health gain within the available funds. The relevance of CEA in health care systems is explained, using varicose vein treatment in the UK NHS as an example. Treatment for varicose veins is often not commissioned to at a local level, most likely because it is misperceived to be a cosmetic problem. However, this view does not take into account the impact of quality of life. CEA balances costs against a quantitative measure of health related quality of life, and could therefore be used to determine whether it is cost-effective to provide varicose vein treatment. The current literature on the cost-effectiveness of varicose vein treatment is reviewed, and an overview of cost-effectiveness principles is provided. Concepts such as economic modelling, incremental cost-effectiveness ratios (ICERs), net monetary benefit (NMB) and sensitivity analysis are explained, using examples relevant to varicose veins where appropriate. This article explains how, far from cutting costs and sacrificing patient health, CEA provides a useful tool to maximise the health of the population in the face of ever tightening budget constraints. CEA could be used to compare the cost-effectiveness of the various treatment options for varicose veins, and efficiencies realised.

Longitudinal Proximity Effect, Lateral Inverse Proximity Effect, and Nonequilibrium Superconductivity in Transition-Edge Sensors

NASA Technical Reports Server (NTRS)

Sadleir, John E.

2010-01-01

We have recently shown that normal-metal/superconductor (N /S) bilayer TESs (superconducting Transition-Edge Sensors) exhibit weak-link behavior. Our measurements were explained in terms of a longitudinal proximity effect model in which superconducting order from the higher transition temperature leads is induced into the TES bilayer plane over remarkably long distances (up to 290 micron). Here we extend our understanding to include TESs with added noise-mitigating normal-metal structures (N structures). We explain our results in terms of an effect converse to the longitudinal proximity effect (LoPE), the lateral inverse proximity effect (LaiPE), for which the order parameter in the N /S bilayer is reduced due to the neighboring N structures. We present resistance and critical current measurements as a function of temperature and magnetic field taken on square Mo/Au bilayer TESs with lengths ranging from 8 to 130 micron with and without added N structures. We observe the inverse proximity effect on the bilayer over in-plane distances many tens of microns and find the transition shifts to lower temperatures scale approximately as the inverse square of the in-plane N-structure separation distance, without appreciable broadening of the transition width. We find TESs with added Au structures exhibit weak-link behavior as evidenced by exponential temperature dependence of the critical current and Josephson-like oscillations of the critical current with applied magnetic field. We also present evidence for nonequilbrium superconductivity and estimate a quasiparticle lifetime of 1.8 x 10(exp -10) s for the bilayer. The LoPE model is also used to explain the increased conductivity at temperatures above the bilayer's steep resistive transition.

Long-term Outcomes of the FRESH START Trial: Exploring the Role of Self-efficacy in Cancer Survivors’ Maintenance of Dietary Practices and Physical Activity

PubMed Central

Mosher, Catherine E.; Lipkus, Isaac; Sloane, Richard; Snyder, Denise C.; Lobach, David F.; Demark-Wahnefried, Wendy

2012-01-01

Objective This study examined whether changes in self-efficacy explain the effects of a mailed print intervention on long-term dietary practices of breast and prostate cancer survivors. The relationship between change in self-efficacy and long-term physical activity (PA) also was examined. Methods Breast and prostate cancer survivors (N=543) from 39 U.S. states and two Canadian provinces participated in the FRESH START intervention trial. Participants were randomly assigned to receive a 10-month program of mailed print materials on diet and PA available in the public domain or a 10-month program of tailored materials designed to increase fruit and vegetable (F&V) intake, decrease fat intake, and/or increase PA. Changes in self-efficacy for F&V intake and fat restriction were analyzed as potential mediators of the intervention’s effects on diet at 2-year follow-up. Because we previously found that change in self-efficacy for PA did not vary by group assignment, the relationship between change in self-efficacy and PA at 2-year follow-up was examined across study conditions. Results Results suggest that change in self-efficacy for fat restriction partially explained the intervention’s effect on fat intake (mean indirect effect=-.28), and change in self-efficacy for F&V consumption partially explained the intervention’s effect on daily F&V intake (mean indirect effect=.11). Change in self-efficacy for fat restriction partially accounted for the intervention’s impact on overall diet quality among men only (mean indirect effect=.60). Finally, change in self-efficacy for PA predicted PA at 2-year follow-up. Conclusions Findings suggest that self-efficacy may influence long-term maintenance of healthy lifestyle practices among cancer survivors. PMID:22544562

The extent of using mobility assistive devices can partly explain fatigue among persons with late effects of polio - a retrospective registry study in Sweden.

PubMed

Santos Tavares Silva, I; Sunnerhagen, K S; Willén, C; Ottenvall Hammar, I

2016-11-18

Fatigue is reported as one of the most disabling symptoms and is common among persons living with late effects of polio. Although fatigue has been studied in the context of people living with late effects of polio, there is a lack of knowledge concerning the association of fatigue and variables of importance for participation in daily life. Therefore, the aim of this study was to explore possible factors associated with fatigue among persons with late effects of polio in Sweden. This retrospective registry study consisted of 89 persons with late effects of polio living in Sweden. Fatigue was measured with the Multidimensional Fatigue Inventory (MFI-20) scale, Swedish version. Pearson's correlation coefficient was used to analyse the correlation between the factors and fatigue, and a multiple linear regression was carried out to explore factors for fatigue. Fatigue statistically significantly correlated with age (r = 0.234, p < 0.05) and the use of mobility assistive devices (r = 0.255, p < 0.05). The multiple linear regression model showed that the factors age (β = 0.304, p < 0.019) and mobility assistive devices (β = 0.262, p < 0.017) were associated with fatigue among persons living with late effects of polio, and the model partly explained 14% of the variation of fatigue. Fatigue could partly be explained by the extent of using mobility assistive devices and age. Healthcare professionals should provide and demonstrate the importance of assistive devices to ensure management of fatigue in persons living with late effects of polio.

Mutual Cross-Feeding Interactions between Bifidobacterium longum subsp. longum NCC2705 and Eubacterium rectale ATCC 33656 Explain the Bifidogenic and Butyrogenic Effects of Arabinoxylan Oligosaccharides

PubMed Central

Rivière, Audrey; Gagnon, Mérilie; Weckx, Stefan; Roy, Denis

2015-01-01

Arabinoxylan oligosaccharides (AXOS) are a promising class of prebiotics that have the potential to stimulate the growth of bifidobacteria and the production of butyrate in the human colon, known as the bifidogenic and butyrogenic effects, respectively. Although these dual effects of AXOS are considered beneficial for human health, their underlying mechanisms are still far from being understood. Therefore, this study investigated the metabolic interactions between Bifidobacterium longum subsp. longum NCC2705 (B. longum NCC2705), an acetate producer and arabinose substituent degrader of AXOS, and Eubacterium rectale ATCC 33656, an acetate-converting butyrate producer. Both strains belong to prevalent species of the human colon microbiota. The strains were grown on AXOS during mono- and coculture fermentations, and their growth, AXOS consumption, metabolite production, and expression of key genes were monitored. The results showed that the growth of both strains and gene expression in both strains were affected by cocultivation and that these effects could be linked to changes in carbohydrate consumption and concomitant metabolite production. The consumption of the arabinose substituents of AXOS by B. longum NCC2705 with the concomitant production of acetate allowed E. rectale ATCC 33656 to produce butyrate (by means of a butyryl coenzyme A [CoA]:acetate CoA-transferase), explaining the butyrogenic effect of AXOS. Eubacterium rectale ATCC 33656 released xylose from the AXOS substrate, which favored the B. longum NCC2705 production of acetate, explaining the bifidogenic effect of AXOS. Hence, those interactions represent mutual cross-feeding mechanisms that favor the coexistence of bifidobacterial strains and butyrate producers in the same ecological niche. In conclusion, this study provides new insights into the bifidogenic and butyrogenic effects of AXOS. PMID:26319874

No blank slates: Pre-existing schemas about pharmaceuticals predict memory for side effects.

PubMed

Heller, Monika K; Chapman, Sarah C E; Horne, Rob

2017-04-01

Attribution of symptoms as medication side effects is informed by pre-existing beliefs about medicines and perceptions of personal sensitivity to their effects (pharmaceutical schemas). We tested whether (1) pharmaceutical schemas were associated with memory (recall/recognition) for side effect information (2) memory explained the attribution of a common unrelated symptom as a side effect. In this analogue study participants saw the patient leaflet of a fictitious asthma drug listing eight side effects. We measured recall and recognition memory for side effects and used a vignette to test whether participants attributed an unlisted common symptom (headache) as a side effect. Participants who perceived pharmaceuticals as more harmful in general recalled fewer side effects correctly (r Correct Recall  = -.273), were less able to differentiate between listed and unlisted side effects (r Recognition Sensitivity  = -.256) and were more likely to attribute the unlisted headache symptom as a side effect (r side effect attribution  = .381, ps < .01). The effect of harm beliefs on side effect attribution was partially mediated by correct recall of side effects. Pharmaceutical schemas are associated with memory for side effect information. Memory may explain part of the association between pharmaceutical schemas and the attribution of unrelated symptoms as side effects.

Revisiting the classics: considering nonconsumptive effects in textbook examples of predator-prey interactions.

PubMed

Peckarsky, Barbara L; Abrams, Peter A; Bolnick, Daniel I; Dill, Lawrence M; Grabowski, Jonathan H; Luttbeg, Barney; Orrock, John L; Peacor, Scott D; Preisser, Evan L; Schmitz, Oswald J; Trussell, Geoffrey C

2008-09-01

Predator effects on prey dynamics are conventionally studied by measuring changes in prey abundance attributed to consumption by predators. We revisit four classic examples of predator-prey systems often cited in textbooks and incorporate subsequent studies of nonconsumptive effects of predators (NCE), defined as changes in prey traits (e.g., behavior, growth, development) measured on an ecological time scale. Our review revealed that NCE were integral to explaining lynx-hare population dynamics in boreal forests, cascading effects of top predators in Wisconsin lakes, and cascading effects of killer whales and sea otters on kelp forests in nearshore marine habitats. The relative roles of consumption and NCE of wolves on moose and consequent indirect effects on plant communities of Isle Royale depended on climate oscillations. Nonconsumptive effects have not been explicitly tested to explain the link between planktonic alewives and the size structure of the zooplankton, nor have they been invoked to attribute keystone predator status in intertidal communities or elsewhere. We argue that both consumption and intimidation contribute to the total effects of keystone predators, and that characteristics of keystone consumers may differ from those of predators having predominantly NCE. Nonconsumptive effects are often considered as an afterthought to explain observations inconsistent with consumption-based theory. Consequently, NCE with the same sign as consumptive effects may be overlooked, even though they can affect the magnitude, rate, or scale of a prey response to predation and can have important management or conservation implications. Nonconsumptive effects may underlie other classic paradigms in ecology, such as delayed density dependence and predator-mediated prey coexistence. Revisiting classic studies enriches our understanding of predator-prey dynamics and provides compelling rationale for ramping up efforts to consider how NCE affect traditional predator-prey models based on consumption, and to compare the relative magnitude of consumptive and NCE of predators.

The Importance of Stochastic Effects for Explaining Entrainment in the Zebrafish Circadian Clock.

PubMed

Heussen, Raphaela; Whitmore, David

2015-01-01

The circadian clock plays a pivotal role in modulating physiological processes and has been implicated, either directly or indirectly, in a range of pathological states including cancer. Here we investigate how the circadian clock is entrained by external cues such as light. Working with zebrafish cell lines and combining light pulse experiments with simulation efforts focused on the role of synchronization effects, we find that even very modest doses of light exposure are sufficient to trigger some entrainment, whereby a higher light intensity or duration correlates with strength of the circadian signal. Moreover, we observe in the simulations that stochastic effects may be considered an essential feature of the circadian clock in order to explain the circadian signal decay in prolonged darkness, as well as light initiated resynchronization as a strong component of entrainment.

Super-Luminal Effects for Finsler Branes as a Way to Preserve the Paradigm of Relativity Theories

NASA Astrophysics Data System (ADS)

Vacaru, Sergiu I.

2013-06-01

Using Finsler brane solutions [see details and methods in: S. Vacaru, Class. Quant. Grav. 28:215001, 2011], we show that neutrinos may surpass the speed of light in vacuum which can be explained by trapping effects from gravity theories on eight dimensional (co) tangent bundles on Lorentzian manifolds to spacetimes in general and special relativity. In nonholonomic variables, the bulk gravity is described by Finsler modifications depending on velocity/momentum coordinates. Possible super-luminal phenomena are determined by the width of locally anisotropic brane (spacetime) and induced by generating functions and integration functions and constants in coefficients of metrics and nonlinear connections. We conclude that Finsler brane gravity trapping mechanism may explain neutrino super-luminal effects and almost preserve the paradigm of Einstein relativity as the standard one for particle physics and gravity.

The role of attention problems and impulsiveness in media violence effects on aggression.

PubMed

Swing, Edward L; Anderson, Craig A

2014-01-01

Previous research has established media violence as a causal risk factor for aggressive behavior. Several theoretical mechanisms have been identified to explain this effect. The present study assessed 422 undergraduate students to test the possibility that individual differences in attention problems and impulsiveness can help explain the link between violent media and aggression. Attention problems and impulsiveness proved to be a distinct construct from other processes believed to mediate aggression (aggressive beliefs, aggression related schemata, trait anger, and trait hostility). Attention problems and impulsiveness were uniquely related to both media exposure (total weekly hours and violent content) and aggression. Attention problems and impulsiveness were particularly related to impulsive (as opposed to premeditated) aggression. These results suggest that attention problems and impulsiveness may play an important role in violent media effects on aggression. © 2014 Wiley Periodicals, Inc.

The Effect of QBO on the Total Mass Density

NASA Astrophysics Data System (ADS)

Saǧır, Selçuk; Atıcı, Ramazan

2016-07-01

The relationship between Quasi-Biennial Oscillation (QBO) measured at 10 hPa altitude and total mass density (TMD) values obtained from NRLMSIS-00 model for 90 km altitude of ionosphere known as Mesosphere-Lower Thermosphere (MLT) region is statistically investigated. For this study, multiple-regression model is used. To see the effect on TMD of QBO directions, Dummy variables are also added to model. In the result of calculations, it is observed that QBO is effected on TMD. It is determined that 69% of variations at TMD can be explainable by QBO. It is determined that the explainable ratio is at the rate of 5%. Also, it is seen that an increase/a decrease of 1 meter per second at QBO give rise to an increase/a decrease of 7,2x10-4 g/cm3 at TMD.

Reinforcement expectations explain the relationship between depressive history and smoking status in college students.

PubMed

McChargue, Dennis E; Spring, Bonnie; Cook, Jessica W; Neumann, Christopher A

2004-07-01

Little is understood about biobehavioral mechanisms that mediate the comorbidity between cigarette smoking and depression. We hypothesized that expectancies about nicotine's reinforcing effects are associated with vulnerability to depression, and may partially explain the relationship between history of depression and smoking. Young adult smokers and never smokers (N=175, mean age=19.9 years, S.D.=3.2) were assessed for history of depression and expectations about the negative (e.g., dispels bad moods) and positive (e.g., increases pleasure) reinforcing effects of smoking. Results are inconsistent with the premise that negative reinforcement expectancies mediate the comorbidity between depression and nicotine dependence. Instead, findings suggest that young adults with a prior history of major depression hold exaggerated expectations about nicotine's positive effects, which could enhance their likelihood of initiating smoking. Copyright 2004 Elsevier Ltd.

The Role of Leaders’ Working Alliance in Premarital Education

PubMed Central

Owen, Jesse J.; Rhoades, Galena K.; Stanley, Scott M.; Markman, Howard J.

2011-01-01

Premarital (and general relationship) education programs, as a prevention method, have been shown to have a positive effect on marital quality and can prevent divorce. However, it is unclear whether these positive effects are consistent across leaders who conduct premarital education programs. Examining the variability in relationship outcomes attributed to the leaders of premarital education programs, and the role of general therapeutic factors such as working alliance in explaining relationship outcomes, may help increase the effectiveness of these programs. Accordingly, this study examined 31 leaders who trained 118 couples (236 attendees) in a randomized clinical trial of PREP, a research-based and empirically supported premarital education program being compared to a treatment as usual track. The results demonstrated that couples’ relationship outcomes from pre to post training varied based on the leader who provided the premarital education training. Both training in PREP and aggregated leader working alliance quality (as rated by attendees) explained variability between leaders in change in attendees’ observed negative and positive communication. Leaders’ aggregated working alliance quality also explained change in relationship satisfaction. Additionally, attendees’ ratings of their leaders’ working alliance predicted change in their relationship satisfaction and confidence, and attendees had higher positive communication when they reported better working alliance with their leader. PMID:21355646

Snacking now or later? Individual differences in following intentions or habits explained by time perspective.

PubMed

Onwezen, M C; Van 't Riet, J; Dagevos, H; Sijtsema, S J; Snoek, H M

2016-12-01

Even when individuals are aware of long-term health effects of their diet, and form healthy intentions, they often engage in relatively unhealthy snacking habits. Some individuals fall back on unhealthy habits more easily than others. We aim to explore whether time perspective can explain why some individuals are more prone to rely on habits and others on intentions. Study 1 (N = 1503) provides a first exploration of the role of time perspective by exploring individual differences in perception of long-term and short-term consequences. In accordance with our hypotheses, Study 1 shows that habits are associated with short-term consequences and intentions with long-term consequences. Study 2 (N = 1497) shows that the effects of habits on snacking behaviour are strengthened by a present time perspective, whereas the effects of intentions on snacking behaviour are strengthened by a future time perspective. These findings imply that there is a fundamental difference in the guiding function of intentions and habits which might explain individual differences in following intentions versus habits. Individuals with a long-term perspective are more inclined to follow intentions and individuals with a short-term perspective are more inclined to follow habits. Copyright © 2016 Elsevier Ltd. All rights reserved.

Topology simplification: Important biological phenomenon or evolutionary relic?. Comment on "Disentangling DNA molecules" by Alexander Vologodskii

NASA Astrophysics Data System (ADS)

Bates, Andrew D.; Maxwell, Anthony

2016-09-01

The review, Disentangling DNA molecules[1], gives an excellent technical description of the phenomenon of topology simplification (TS) by type IIA DNA topoisomerases (topos). In the 20 years since its discovery [2], this effect has attracted a good deal of attention, probably because of its apparently magical nature, and because it seemed to offer a solution to the conundrum that all type II topos rely on ATP hydrolysis, but only bacterial DNA gyrases were known to transduce the free energy of hydrolysis into torsion (supercoiling) in the DNA. It made good sense to think that the other enzymes are using the energy to reduce the level of supercoiling, knotting, and particularly decatenation (unlinking), below equilibrium, since the key activity of the non-supercoiling topos is the removal of links between daughter chromosomes [3]. As Vologodskii discusses [1], there have been a number of theoretical models developed to explain how the local effect of a type II topo can influence the global level of knotting and catenation in large DNA molecules, and he explains how features of two of the most successful models (bent G segment and hooked juxtapositions) may be combined to explain the magnitude of the effect and overcome a kinetic problem with the hooked juxtaposition model.

Neural network models - a novel tool for predicting the efficacy of growth hormone (GH) therapy in children with short stature.

PubMed

Smyczynska, Joanna; Hilczer, Maciej; Smyczynska, Urszula; Stawerska, Renata; Tadeusiewicz, Ryszard; Lewinski, Andrzej

2015-01-01

The leading method for prediction of growth hormone (GH) therapy effectiveness are multiple linear regression (MLR) models. Best of our knowledge, we are the first to apply artificial neural networks (ANN) to solve this problem. For ANN there is no necessity to assume the functions linking independent and dependent variables. The aim of study is to compare ANN and MLR models of GH therapy effectiveness. Analysis comprised the data of 245 GH-deficient children (170 boys) treated with GH up to final height (FH). Independent variables included: patients' height, pre-treatment height velocity, chronological age, bone age, gender, pubertal status, parental heights, GH peak in 2 stimulation tests, IGF-I concentration. The output variable was FH. For testing dataset, MLR model predicted FH SDS with average error (RMSE) 0.64 SD, explaining 34.3% of its variability; ANN model derived on the same pre-processed data predicted FH SDS with RMSE 0.60 SD, explaining 42.0% of its variability; ANN model derived on raw data predicted FH with RMSE 3.9 cm (0.63 SD), explaining 78.7% of its variability. ANN seem to be valuable tool in prediction of GH treatment effectiveness, especially since they can be applied to raw clinical data.

The role of rewards and demands in burnout among surgical nurses.

PubMed

Basińska, Beata A; Wilczek-Rużyczka, Ewa

2013-08-01

Job rewards have both, an intrinsic and an extrinsic motivational potential, and lead to employees' development as well as help them to achieve work goals. Rewards can balance job demands and protect from burnout. Due to changes on the labour market, new studies are needed. The aim of our study was to examine the role of demands and individual rewards (and their absence) in burnout among surgical nurses. The study was conducted in 2009 and 2010 with 263 nurses who worked in surgical wards and clinics in hospitals in Southern Poland. The hypotheses were tested by the use of measures of demands and rewards (Effort-Reward Imbalance Questionnaire by Siegrist) and burnout syndrome (Maslach Burnout Inventory). A cross-sectional, correlational study design was applied. Nurses experienced the largest deficiencies in salary and prestige. Exhaustion was explained by stronger demands and lack of respect (large effect). Depersonalization was explained by stronger demands, lack of respect and greater job security (medium effect). Reduced personal achievement was explained by more demands and greater job security (small effect). Excessive demands and lack of esteem are key reasons for burnout among surgical nurses. Job security can increase burnout when too many resources are invested and career opportunities do not appear. These results may help to improve human resource management in the healthcare sector.

Understanding the extraocular muscles and oculomotor, trochlear, and abducens nerves through a simulation in physical examination training: an innovative approach.

PubMed

Zhang, Niu; He, Xiaohua

2010-01-01

The purpose of this study was to investigate the effect of an innovative exhibitory eye model simulation in a physical examination laboratory format on explaining Listing's Law concerning the individual extraocular muscle action and the rationale for cranial nerve testing. Participants were 71 volunteers in the third quarter of a chiropractic training program. The study involved a specially designed eyeball model used to explain the movements of individual extraocular muscles based on Listing's law and their cranial innervations in conjunction with the physical examination. Pre- and post-written tests were used to assess participants' understanding of the subjects taught. The test results were compared with those of nonparticipants who also took the same pre- and posttests. An independent samples t-test of the posttest showed a significant difference between the groups. The study group students achieved higher scores than their counterparts in the control group. Using an innovative approach to explain Listing's law and rationale for cranial nerve tests can improve physical examination skill and help produce more effective written test results.

A simple model of entropy relaxation for explaining effective activation energy behavior below the glass transition temperature.

PubMed

Bisquert, Juan; Henn, François; Giuntini, Jean-Charles

2005-03-01

Strong changes in relaxation rates observed at the glass transition region are frequently explained in terms of a physical singularity of the molecular motions. We show that the unexpected trends and values for activation energy and preexponential factor of the relaxation time tau, obtained at the glass transition from the analysis of the thermally stimulated current signal, result from the use of the Arrhenius law for treating the experimental data obtained in nonstationary experimental conditions. We then demonstrate that a simple model of structural relaxation based on a time dependent configurational entropy and Adam-Gibbs relaxation time is sufficient to explain the experimental behavior, without invoking a kinetic singularity at the glass transition region. The pronounced variation of the effective activation energy appears as a dynamic signature of entropy relaxation that governs the change of relaxation time in nonstationary conditions. A connection is demonstrated between the peak of apparent activation energy measured in nonequilibrium dielectric techniques, with the overshoot of the dynamic specific heat that is obtained in calorimetry techniques.

Matched samples logistic regression in case-control studies with missing values: when to break the matches.

PubMed

Hansson, Lisbeth; Khamis, Harry J

2008-12-01

Simulated data sets are used to evaluate conditional and unconditional maximum likelihood estimation in an individual case-control design with continuous covariates when there are different rates of excluded cases and different levels of other design parameters. The effectiveness of the estimation procedures is measured by method bias, variance of the estimators, root mean square error (RMSE) for logistic regression and the percentage of explained variation. Conditional estimation leads to higher RMSE than unconditional estimation in the presence of missing observations, especially for 1:1 matching. The RMSE is higher for the smaller stratum size, especially for the 1:1 matching. The percentage of explained variation appears to be insensitive to missing data, but is generally higher for the conditional estimation than for the unconditional estimation. It is particularly good for the 1:2 matching design. For minimizing RMSE, a high matching ratio is recommended; in this case, conditional and unconditional logistic regression models yield comparable levels of effectiveness. For maximizing the percentage of explained variation, the 1:2 matching design with the conditional logistic regression model is recommended.

Evaluating the impact of virtualization characteristics on SaaS adoption

NASA Astrophysics Data System (ADS)

Tomás, Sara; Thomas, Manoj; Oliveira, Tiago

2018-03-01

Software as a service (SaaS) is a service model in which the applications are accessible from various client devices through internet. Several studies report possible factors driving the adoption of SaaS but none have considered the perception of the SaaS features and the organization's context. We propose an integrated research model that combines the process virtualization theory (PVT), the technology-organization-environment (TOE) framework and the institutional theory (INT). PVT seeks to explain whether processes are suitable for migration into virtual environments via an information technology-based mechanism as SaaS. The TOE framework seeks to explain the effects of the intra-organizational factors, while INT seeks to explain the effects of the inter-organizational factors on the technology adoption. This research addresses a gap in the SaaS adoption literature by studying the internal perception of the technical features of SaaS and technology, organization, and environment perspectives. Additionally, the integration of PVT, the TOE framework, and INT contributes to the information system (IS) discipline, deepening the applicability and strengths of these theories.

Habitat history improves prediction of biodiversity in rainforest fauna

PubMed Central

Graham, Catherine H.; Moritz, Craig; Williams, Stephen E.

2006-01-01

Patterns of biological diversity should be interpreted in light of both contemporary and historical influences; however, to date, most attempts to explain diversity patterns have largely ignored history or have been unable to quantify the influence of historical processes. The historical effects on patterns of diversity have been hypothesized to be most important for taxonomic groups with poor dispersal abilities. We quantified the relative stability of rainforests over the late Quaternary period by modeling rainforest expansion and contraction in 21 biogeographic subregions in northeast Australia across four time periods. We demonstrate that historical habitat stability can be as important, and in endemic low-dispersal taxa even more important, than current habitat area in explaining spatial patterns of species richness. In contrast, patterns of endemic species richness for taxa with high dispersal capacity are best predicted by using current environmental parameters. We also show that contemporary patterns of species turnover across the region are best explained by historical patterns of habitat connectivity. These results clearly demonstrate that spatially explicit analyses of the historical processes of persistence and colonization are both effective and necessary for understanding observed patterns of biodiversity. PMID:16407139

Explaining Effects and Side Effects of School Inspections: A Path Analysis

ERIC Educational Resources Information Center

Penninckx, Maarten; Vanhoof, Jan; De Maeyer, Sven; Van Petegem, Peter

2016-01-01

There are large differences between schools with regard to how they are affected by a school inspection. This study provides quantitative evidence about the extent to which perceived effects and side effects of an inspection are related to the inspection's judgement on the school, to features of the inspection, and to school features. This study…

Dealing with Dependence (Part I): Understanding the Effects of Clustered Data

ERIC Educational Resources Information Center

McCoach, D. Betsy; Adelson, Jill L.

2010-01-01

This article provides a conceptual introduction to the issues surrounding the analysis of clustered (nested) data. We define the intraclass correlation coefficient (ICC) and the design effect, and we explain their effect on the standard error. When the ICC is greater than 0, then the design effect is greater than 1. In such a scenario, the…

Family Configuration and Achievement: Effects of Birth Order and Family Size in a Sample of Brothers.

ERIC Educational Resources Information Center

Olneck, Michael R.; Bills, David B.

1979-01-01

Birth order effects in brothers were found to derive from difference in family size. Effects for family size were found even with socioeconomic background controlled. Nor were family size effects explained by parental ability. The importance of unmeasured preferences or economic resources that vary across families was suggested. (Author/RD)

Comparing Apples and Oranges: Does Cost-Effectiveness Analysis Deal Fairly with the Old and Young?

ERIC Educational Resources Information Center

Welch, H. Gilbert

1991-01-01

Considers role patient age plays in cost-effectiveness analysis. Quantifies magnitude of age bias and describes means to modify it. Present value analysis (discounting) is demonstrated to markedly attenuate effect of patient age on cost-effectiveness analysis. Explains how, as discount rate grows, difference in potential "life-years" between old…

The Road to Success . . . Driving toward Effective Citizenship.

ERIC Educational Resources Information Center

Winter, Deb; Rice, Chris

2000-01-01

Describes Lawton (Michigan) Elementary School's "Road to Success" program, which emerged from concern for students' knowledge of civics and ability to participate as effective citizens. Explains that an important aspect of the program is its focus on Core Democratic Values. (CMK)

Book Discounts and Cost-Plus Pricing

ERIC Educational Resources Information Center

Andresen, David C.

1974-01-01

The adoption of cost-plus pricing by a major book jobber may have profound effects on the discounts that libraries receive. The article explains the pricing system and presents a set of graphs for libraries to use to determine its effects. (Author)

Ellipsis Reconsidered

ERIC Educational Resources Information Center

Kertz, Laura

2010-01-01

I present an analysis of antecedent mismatch effects under ellipsis based on information structure, in which apparent syntactic parallelism effects are explained as a consequence of an information structural constraint requiring topic/comment parallelism for contrastive topics. Experimental findings in support of this hypothesis demonstrate first…

Sex determination, longevity, and the birth and death of reptilian species.

PubMed

Sabath, Niv; Itescu, Yuval; Feldman, Anat; Meiri, Shai; Mayrose, Itay; Valenzuela, Nicole

2016-08-01

Vertebrate sex-determining mechanisms (SDMs) are triggered by the genotype (GSD), by temperature (TSD), or occasionally, by both. The causes and consequences of SDM diversity remain enigmatic. Theory predicts SDM effects on species diversification, and life-span effects on SDM evolutionary turnover. Yet, evidence is conflicting in clades with labile SDMs, such as reptiles. Here, we investigate whether SDM is associated with diversification in turtles and lizards, and whether alterative factors, such as lifespan's effect on transition rates, could explain the relative prevalence of SDMs in turtles and lizards (including and excluding snakes). We assembled a comprehensive dataset of SDM states for squamates and turtles and leveraged large phylogenies for these two groups. We found no evidence that SDMs affect turtle, squamate, or lizard diversification. However, SDM transition rates differ between groups. In lizards TSD-to-GSD surpass GSD-to-TSD transitions, explaining the predominance of GSD lizards in nature. SDM transitions are fewer in turtles and the rates are similar to each other (TSD-to-GSD equals GSD-to-TSD), which, coupled with TSD ancestry, could explain TSD's predominance in turtles. These contrasting patterns can be explained by differences in life history. Namely, our data support the notion that in general, shorter lizard lifespan renders TSD detrimental favoring GSD evolution in squamates, whereas turtle longevity permits TSD retention. Thus, based on the macro-evolutionary evidence we uncovered, we hypothesize that turtles and lizards followed different evolutionary trajectories with respect to SDM, likely mediated by differences in lifespan. Combined, our findings revealed a complex evolutionary interplay between SDMs and life histories that warrants further research that should make use of expanded datasets on unexamined taxa to enable more conclusive analyses.

Explaining academic-track boys' underachievement in language grades: Not a lack of aptitude but students' motivational beliefs and parents' perceptions?

PubMed

Heyder, Anke; Kessels, Ursula; Steinmayr, Ricarda

2017-06-01

Boys earn lower grades in languages than girls. The expectancy-value model by Eccles et al. (, A series of books in psychology. Achievement and achievement motives. Psychological and sociological approaches, W.H. Freeman, San Francisco, CA, 76) is a comprehensive theoretical model for explaining gender differences in educational outcomes. In the past, most studies have focused on girls' disadvantage in math and science and on the role of the students' motivational beliefs. We aimed to explain boys' lower language grades by applying the expectancy-value model while taking into account students' motivational beliefs as well as their aptitude, prior achievement, and socializers' beliefs. In addition, we aimed at exploring the incremental contribution of each potential mediator. Five hundred and twenty German students (age M = 17 years; 58% female) and 374 parents (age M = 47 years). Student-reported ability self-concept (ASC) and task values, parents' perceptions of students' ability, students' prior achievement as reported by schools, and students' verbal intelligence test scores were all tested as mediators of the effect of gender on grades in German while controlling for parents' socioeconomic status. Single-mediator models and a multiple-mediator model were estimated using structural equation modelling. All variables proved to be relevant for explaining boys' underachievement in language grades. Whereas students' ASC, task values, prior achievement, and parents' perceptions mediated the gender effect, verbal intelligence was identified as a suppressor variable increasing the gender effect. Our results challenge the stereotypic belief that boys' lower grades are due to lower verbal aptitude. Rather, students' motivational beliefs and parents' perceptions seem critical factors. Implications for both future research and practice are discussed. © 2017 The British Psychological Society.

Economic development and road traffic fatalities in Russia: analysis of federal regions 2004-2011.

PubMed

He, Huan; Paichadze, Nino; Hyder, Adnan A; Bishai, David

2015-12-01

The relationship between economic development and road safety at sub-national level has not been well established. This study aims to assess the relationships between economic growth (measured by gross regional product (GRP)) and road traffic fatalities (RTFs) and crash fatality ratio (CFR) at sub-national level in Russia. We used published secondary data on annual RTFs and CFR obtained from the traffic police and socioeconomic development indicators from the statistics department for each Russian federal region (referred to in Russia as "subject") for 2004-2011. We used multivariate fixed effects models for longitudinal data to examine the GRP-RTF and the GRP-CFR relationships excluding regions with extreme values. Time (in years) and a set of relevant socioeconomic variables (territory, population, number of privately owned cars, number of public buses, length of public motor roads, number of physicians, and budget expenditure on health care and physical wellness) were also included as covariates in the models. The RTF rates decreased monotonically over time as GRP per capita increased in 66 studied regions during 2004-2011. This relationship was mainly explained by the number of privately owned cars and partially explained by year dummy variables, number of buses, and number of physicians. CFR also decreased monotonically as GRP per capita increased in 67 studied regions. This relationship between economic growth and CFR was fully explained by secular time trends. The year dummy effects on CFR were not mediated by other socioeconomic variables included in the study. For the period of 2004-2011 in Russia, the reduction in RTFs is mostly explained by increasing the number of private cars, while the reduction of CFR is mostly associated with year-effects suggesting a process of diffusion of knowledge, which is not solely dominated by economic growth.

Testing the Effectiveness of Environmental Variables to Explain European Terrestrial Vertebrate Species Richness across Biogeographical Scales

PubMed Central

Mouchet, Maud; Levers, Christian; Zupan, Laure; Kuemmerle, Tobias; Plutzar, Christoph; Erb, Karlheinz; Lavorel, Sandra; Thuiller, Wilfried; Haberl, Helmut

2015-01-01

We compared the effectiveness of environmental variables, and in particular of land-use indicators, to explain species richness patterns across taxonomic groups and biogeographical scales (i.e. overall pan-Europe and ecoregions within pan-Europe). Using boosted regression trees that handle non-linear relationships, we compared the relative influence (as a measure of effectiveness) of environmental variables related to climate, landscape (or habitat heterogeneity), land-use intensity or energy availability to explain European vertebrate species richness (birds, amphibians, and mammals) at the continental and ecoregion scales. We found that dominant land cover and actual evapotranspiration that relate to energy availability were the main correlates of vertebrate species richness over Europe. At the ecoregion scale, we identified four distinct groups of ecoregions where species richness was essentially associated to (i) seasonality of temperature, (ii) actual evapotranspiration and/or mean annual temperature, (iii) seasonality of precipitation, actual evapotranspiration and land cover) and (iv) and an even combination of the environmental variables. This typology of ecoregions remained valid for total vertebrate richness and the three vertebrate groups taken separately. Despite the overwhelming influence of land cover and actual evapotranspiration to explain vertebrate species richness patterns at European scale, the ranking of the main correlates of species richness varied between regions. Interestingly, landscape and land-use indicators did not stand out at the continental scale but their influence greatly increased in southern ecoregions, revealing the long-lasting human footprint on land-use–land-cover changes. Our study provides one of the first multi-scale descriptions of the variability in the ranking of correlates across several taxa. PMID:26161981

The influence of the starvation-predation trade-off on the relationship between ambient temperature and body size among endotherms.

PubMed

McNamara, John M; Higginson, Andrew D; Verhulst, Simon

2016-04-01

The tendency for animals at higher latitudes to be larger (Bergmann's rule) is generally explained by recourse to latitudinal effects on ambient temperature and the food supply, but these receive only mixed support and do not explain observations of the inverse to Bergmann's rule. Our aim was to better understand how ecological variables might influence body size and thereby explain this mixed support. World-wide. Previous explanations do not allow for the selective pressure exerted by the trade-off between predation and starvation, which we incorporate in a model of optimal body size and energy storage of a generalized homeotherm. In contrast to existing arguments, we concentrate on survival over winter when the food supply is poor and can be interrupted for short periods. We use our model to assess the logical validity of the heat conservation hypothesis and show that it must allow for the roles of both food availability and predation risk. We find that whether the effect of temperature on body size is positive or negative depends on temperature range, predator density, and the likelihood of long interruptions to foraging. Furthermore, changing day length explains differing effects of altitude and latitude on body size, leading to opposite predictions for nocturnal and diurnal endotherms. Food availability and ambient temperature can have counteracting selective pressures on body mass, and can lead to a non-monotonic relationship between latitude and size, as observed in several studies. Our work provides a theoretical framework for understanding the relationships between the costs and benefits of large body size and eco-geographical patterns among endotherms world-wide.

The importance of lake-specific characteristics for water quality across the continental United States.

PubMed

Read, Emily K; Patil, Vijay P; Oliver, Samantha K; Hetherington, Amy L; Brentrup, Jennifer A; Zwart, Jacob A; Winters, Kirsten M; Corman, Jessica R; Nodine, Emily R; Woolway, R Iestyn; Dugan, Hilary A; Jaimes, Aline; Santoso, Arianto B; Hong, Grace S; Winslow, Luke A; Hanson, Paul C; Weathers, Kathleen C

2015-06-01

Lake water quality is affected by local and regional drivers, including lake physical characteristics, hydrology, landscape position, land cover, land use, geology, and climate. Here, we demonstrate the utility of hypothesis testing within the landscape limnology framework using a random forest algorithm on a national-scale, spatially explicit data set, the United States Environmental Protection Agency's 2007 National Lakes Assessment. For 1026 lakes, we tested the relative importance of water quality drivers across spatial scales, the importance of hydrologic connectivity in mediating water quality drivers, and how the importance of both spatial scale and connectivity differ across response variables for five important in-lake water quality metrics (total phosphorus, total nitrogen, dissolved organic carbon, turbidity, and conductivity). By modeling the effect of water quality predictors at different spatial scales, we found that lake-specific characteristics (e.g., depth, sediment area-to-volume ratio) were important for explaining water quality (54-60% variance explained), and that regionalization schemes were much less effective than lake specific metrics (28-39% variance explained). Basin-scale land use and land cover explained between 45-62% of variance, and forest cover and agricultural land uses were among the most important basin-scale predictors. Water quality drivers did not operate independently; in some cases, hydrologic connectivity (the presence of upstream surface water features) mediated the effect of regional-scale drivers. For example, for water quality in lakes with upstream lakes, regional classification schemes were much less effective predictors than lake-specific variables, in contrast to lakes with no upstream lakes or with no surface inflows. At the scale of the continental United States, conductivity was explained by drivers operating at larger spatial scales than for other water quality responses. The current regulatory practice of using regionalization schemes to guide water quality criteria could be improved by consideration of lake-specific characteristics, which were the most important predictors of water quality at the scale of the continental United States. The spatial extent and high quality of contextual data available for this analysis makes this work an unprecedented application of landscape limnology theory to water quality data. Further, the demonstrated importance of lake morphology over other controls on water quality is relevant to both aquatic scientists and managers.

Genome-Wide Association Study for Indicator Traits of Sexual Precocity in Nellore Cattle

PubMed Central

Irano, Natalia; de Camargo, Gregório Miguel Ferreira; Costa, Raphael Bermal; Terakado, Ana Paula Nascimento; Magalhães, Ana Fabrícia Braga; Silva, Rafael Medeiros de Oliveira; Dias, Marina Mortati; Bignardi, Annaiza Braga; Baldi, Fernando; Carvalheiro, Roberto; de Oliveira, Henrique Nunes; de Albuquerque, Lucia Galvão

2016-01-01

The objective of this study was to perform a genome-wide association study (GWAS) to detect chromosome regions associated with indicator traits of sexual precocity in Nellore cattle. Data from Nellore animals belonging to farms which participate in the DeltaGen® and Paint® animal breeding programs, were used. The traits used in this study were the occurrence of early pregnancy (EP) and scrotal circumference (SC). Data from 72,675 females and 83,911 males with phenotypes were used; of these, 1,770 females and 1,680 males were genotyped. The SNP effects were estimated with a single-step procedure (WssGBLUP) and the observed phenotypes were used as dependent variables. All animals with available genotypes and phenotypes, in addition to those with only phenotypic information, were used. A single-trait animal model was applied to predict breeding values and the solutions of SNP effects were obtained from these breeding values. The results of GWAS are reported as the proportion of variance explained by windows with 150 adjacent SNPs. The 10 windows that explained the highest proportion of variance were identified. The results of this study indicate the polygenic nature of EP and SC, demonstrating that the indicator traits of sexual precocity studied here are probably controlled by many genes, including some of moderate effect. The 10 windows with large effects obtained for EP are located on chromosomes 5, 6, 7, 14, 18, 21 and 27, and together explained 7.91% of the total genetic variance. For SC, these windows are located on chromosomes 4, 8, 11, 13, 14, 19, 22 and 23, explaining 6.78% of total variance. GWAS permitted to identify chromosome regions associated with EP and SC. The identification of these regions contributes to a better understanding and evaluation of these traits, and permits to indicate candidate genes for future investigation of causal mutations. PMID:27494397