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Sample records for intrinsic localized modes

  1. Intrinsic localized modes and nonlinear impurity modes in curved ...

    Indian Academy of Sciences (India)

    structure of the localized modes induced by an isotopic light-mass impurity in this chain. We further demonstrate that a ... direct physical meaning and can describe polymers and biomolecular systems. The motion of the chain is confined to .... mode center (n = 0) the local mode must obey the expression (10). Equation (8).

  2. Parametric resonance of intrinsic localized modes in coupled cantilever arrays

    Energy Technology Data Exchange (ETDEWEB)

    Kimura, Masayuki, E-mail: kimura.masayuki.8c@kyoto-u.ac.jp [Department of Electrical Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan); Matsushita, Yasuo [Advanced Mathematical Institute, Osaka City University, 3-3-138 Sughimoto, Sumiyoshi-ku, Osaka 558-8585 (Japan); Hikihara, Takashi [Department of Electrical Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510 (Japan)

    2016-08-19

    In this study, the parametric resonances of pinned intrinsic localized modes (ILMs) were investigated by computing the unstable regions in parameter space consisting of parametric excitation amplitude and frequency. In the unstable regions, the pinned ILMs were observed to lose stability and begin to fluctuate. A nonlinear Klein–Gordon, Fermi–Pasta–Ulam-like, and mixed lattices were investigated. The pinned ILMs, particularly in the mixed lattice, were destabilized by parametric resonances, which were determined by comparing the shapes of the unstable regions with those in the Mathieu differential equation. In addition, traveling ILMs could be generated by parametric excitation. - Highlights: • Destabilization of intrinsic localized modes (ILMs) by parametric excitation is investigated for FPU, NKG, and mixed lattices. • Frequency and amplitude of parametric excitation is determined based on characteristic multipliers of ILMs. • Unstable regions for the mixed lattice case show very similar shape to those of the Mathieu equation. • ILMs become unstable by causing parametric resonance.

  3. Shepherding intrinsic localized modes in micro-mechanical arrays

    Science.gov (United States)

    Sievers, Albert

    The energy profiles of intrinsic localized modes (ILMs) in periodic physical lattices with nonlinear forces resemble those of localized vibrational modes at defects in a harmonic lattice but, like solitons, they can propagate; however, in contrast with solitons they loose energy as they move through the lattice - the more localized the excitation the faster the energy loss. One of our experimental studies with micro-mechanical arrays involves steady state locking of ILMs, and their interactions with impurities. By measuring the linear response spectra of a driven array containing an ILM both the dynamics of bifurcation transitions and the hopping of vibrational energy have been connected to the transition properties of soft modes. Recently the search for a completely mobile ILM has focused attention on minimizing the resonance interaction that occurs between the localized excitation and small amplitude plane wave modes. Via simulations we demonstrate that when more than one type of nonlinear force is present their Fourier components can often be designed to cancel against each other in the k-space region of the plane wave dispersion curve, removing the resonance. The end result is super-transmission for an ILM in a discrete physical lattice. Such an engineered, intrinsic, low loss channel may prove to be a useful property for other physical systems treated within a tight binding approximation. In collaboration with M. Sato.

  4. Transverse intrinsic localized modes in monatomic chain and in graphene

    Energy Technology Data Exchange (ETDEWEB)

    Hizhnyakov, V. [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia); Klopov, M. [Department of Physics, Faculty of Science, Tallinn University of Technology, Ehitajate 5, 19086 Tallinn (Estonia); Shelkan, A., E-mail: shell@ut.ee [Institute of Physics, University of Tartu, Ravila 14c, 50411 Tartu (Estonia)

    2016-03-06

    In this paper an analytical and numerical study of anharmonic vibrations of monatomic chain and graphene in transverse (perpendicular) with respect to the chain/plane direction is presented. Due to the lack of odd anharmonicities and presence of hard quartic anharmonicity for displacements in this direction, there may exist localized anharmonic transverse modes with the frequencies above the spectrum of the corresponding phonons. Although these frequencies are in resonance with longitudinal (chain) or in-plane (graphene) phonons, the modes can decay only due to a weak anharmonic process. Therefore the lifetime of these vibrations may be very long. E.g. in the chain, according to our theoretical and numerical calculations it may exceed 10{sup 10} periods. We call these vibrations as transverse intrinsic localized modes. - Highlights: • In a stretched monatomic chain, long-living nonlinear transverse localized modes may exist. • Transverse vibrations of a chain slowly decay due to creation of longitudinal phonons. • Lifetime of transverse vibrations of a chain may exceed billion periods of vibrations. • In stretched graphene, long-living out-of-plain localized vibrations may exist.

  5. Intrinsic localized modes in arrays of atomic-molecular Bose-Einstein condensates

    International Nuclear Information System (INIS)

    Abdullaev, F.Kh.; Konotop, V.V.

    2003-01-01

    The existence of strongly localized matter solitons, intrinsic localized modes (ILM's), in an array of atomic-molecular Bose-Einstein condensates (AMBEC's) is shown. The theory is based on the Wannier function expansion of the system order parameter and predicts the possibility of strong localization of the atomic and molecular components whose relative populations are determined by the Raman detuning parameter and by the atom-molecule conversion rate. ILM's can possess different symmetries and spatial distributions of the components. In this context AMBEC arrays can be viewed as potential compressors and separators of atomic and molecular condensates

  6. Harnessing intrinsic localized modes to identify impurities in nonlinear periodic systems

    Science.gov (United States)

    Thota, M.; Harne, R. L.; Wang, K. W.

    2015-02-01

    Intrinsic localized modes (ILMs) are concentrations of vibrational energy in periodic systems/lattices due to the combined influences of nonlinearity and discreteness. Moreover, ILMs can move within the system and may strongly interact with an impurity, such as a stiffness change, mass variation, etc. Numerous scientific fields have uncovered examples and evidence of ILMs, motivating a multidisciplinary pursuit to rigorously understand the underlying principles. In spite of the diverse technical studies, a characterization of ILM interaction behaviors with multiple impurities in dissipative lattices remains outstanding. The insights on such behaviors may be broadly useful when dynamic measurements are the only accessible features of the periodic system. For instance, one may guide an ILM within the lattice using a deliberately applied and steered impurity and harness the observed interaction behaviors with a second, static (immovable) impurity/defect to identify how the underlying lattice is different at the second, defected site, whether or not one knew the position of the defect a priori. In this spirit, this research studies, analyzes, and characterizes the interaction types amongst an ILM and multiple impurities, and devises a method to identify a static defect impurity using quantitatively and qualitatively distinct interaction phenomena. The method is found to be robust to moderate levels of lattice stiffness heterogeneity and is applicable to monitor various property changes that represent impurities. Finally, experimental studies verify that ILMs interact with multiple impurities in unique ways such that defect features may be effectively identified.

  7. Algebraic description of intrinsic modes in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A. (Los Alamos National Lab., NM (USA))

    1990-01-01

    We present a procedure for extracting normal modes in algebraic number-conserving systems of interacting bosons relevant for collective states in even-even nuclei. The Hamiltonian is resolved into intrinsic (bandhead related) and collective (in-band related) parts. Shape parameters are introduced through non-spherical boson bases. Intrinsic modes decoupled from the spurious modes are obtained from the intrinsic part of the Hamiltonian in the limit of large number of bosons. Intrinsic states are constructed and serve to evaluate electromagnetic transition rates. The method is illustrated for systems with one type of boson as well as with proton-neutron bosons. (author).

  8. Algebraic description of intrinsic modes in nuclei

    International Nuclear Information System (INIS)

    Leviatan, A.

    1990-01-01

    We present a procedure for extracting normal modes in algebraic number-conserving systems of interacting bosons relevant for collective states in even-even nuclei. The Hamiltonian is resolved into intrinsic (bandhead related) and collective (in-band related) parts. Shape parameters are introduced through non-spherical boson bases. Intrinsic modes decoupled from the spurious modes are obtained from the intrinsic part of the Hamiltonian in the limit of large number of bosons. Intrinsic states are constructed and serve to evaluate electromagnetic transition rates. The method is illustrated for systems with one type of boson as well as with proton-neutron bosons. (author)

  9. Algebraic description of intrinsic modes in nuclei

    International Nuclear Information System (INIS)

    Leviatan, A.

    1989-01-01

    We present a procedure for extracting normal modes in algebraic number-conserving systems of interacting bosons relevant for collective states in even-even nuclei. The Hamiltonian is resolved into intrinsic (bandhead related) and collective (in-band related) parts. Shape parameters are introduced through non-spherical boson bases. Intrinsic modes decoupled from the spurious modes are obtained from the intinsic part of the Hamiltonian in the limit of large number of bosons. Intrinsic states are constructed and serve to evaluate electromagnetic transition rates. The method is illustrated for systems with one type of boson as well as with proton-neutron bosons. 28 refs., 1 fig

  10. Algebraic description of intrinsic modes in nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A.

    1989-01-01

    We present a procedure for extracting normal modes in algebraic number-conserving systems of interacting bosons relevant for collective states in even-even nuclei. The Hamiltonian is resolved into intrinsic (bandhead related) and collective (in-band related) parts. Shape parameters are introduced through non-spherical boson bases. Intrinsic modes decoupled from the spurious modes are obtained from the intinsic part of the Hamiltonian in the limit of large number of bosons. Intrinsic states are constructed and serve to evaluate electromagnetic transition rates. The method is illustrated for systems with one type of boson as well as with proton-neutron bosons. 28 refs., 1 fig.

  11. Localized Acoustic Surface Modes

    KAUST Repository

    Farhat, Mohamed

    2015-08-04

    We introduce the concept of localized acoustic surface modes (ASMs). We demonstrate that they are induced on a two-dimensional cylindrical rigid surface with subwavelength corrugations under excitation by an incident acoustic plane wave. Our results show that the corrugated rigid surface is acoustically equivalent to a cylindrical scatterer with uniform mass density that can be represented using a Drude-like model. This, indeed, suggests that plasmonic-like acoustic materials can be engineered with potential applications in various areas including sensing, imaging, and cloaking.

  12. Depletion-mode quantum dots in intrinsic silicon

    Science.gov (United States)

    Amitonov, Sergey V.; Spruijtenburg, Paul C.; Vervoort, Max W. S.; van der Wiel, Wilfred G.; Zwanenburg, Floris A.

    2018-01-01

    We report the fabrication and electrical characterization of depletion-mode quantum dots in a two-dimensional hole gas (2DHG) in intrinsic silicon. We use fixed charge in a SiO2/Al2O3 dielectric stack to induce a 2DHG at the Si/SiO2 interface. Fabrication of the gate structures is accomplished with a single layer metallization process. Transport spectroscopy reveals regular Coulomb oscillations with charging energies of 10-15 meV and 3-5 meV for the few- and many-hole regimes, respectively. This depletion-mode design avoids complex multilayer architectures requiring precision alignment and allows us to adopt directly best practices already developed for depletion dots in other material systems. We also demonstrate a method to deactivate fixed charge in the SiO2/Al2O3 dielectric stack using deep ultraviolet light, which may become an important procedure to avoid unwanted 2DHG build-up in Si MOS quantum bits.

  13. A Research on Maximum Symbolic Entropy from Intrinsic Mode Function and Its Application in Fault Diagnosis

    Directory of Open Access Journals (Sweden)

    Zhuofei Xu

    2017-01-01

    Full Text Available Empirical mode decomposition (EMD is a self-adaptive analysis method for nonlinear and nonstationary signals. It has been widely applied to machinery fault diagnosis and structural damage detection. A novel feature, maximum symbolic entropy of intrinsic mode function based on EMD, is proposed to enhance the ability of recognition of EMD in this paper. First, a signal is decomposed into a collection of intrinsic mode functions (IMFs based on the local characteristic time scale of the signal, and then IMFs are transformed into a serious of symbolic sequence with different parameters. Second, it can be found that the entropies of symbolic IMFs are quite different. However, there is always a maximum value for a certain symbolic IMF. Third, take the maximum symbolic entropy as features to describe IMFs from a signal. Finally, the proposed features are applied to evaluate the effect of maximum symbolic entropy in fault diagnosis of rolling bearing, and then the maximum symbolic entropy is compared with other standard time analysis features in a contrast experiment. Although maximum symbolic entropy is only a time domain feature, it can reveal the signal characteristic information accurately. It can also be used in other fields related to EMD method.

  14. Intrinsic Low Hysteresis Touch Mode Capacitive Pressure Sensor

    DEFF Research Database (Denmark)

    Fragiacomo, Giulio; Pedersen, Thomas; Hansen, Ole

    2011-01-01

    Hysteresis has always been one of the main concerns when fabricating touch mode capacitive pressure sensors (TMCPS). This phenomenon can be fought at two different levels: during fabrication or after fabrication with the aid of a dedicated signal conditioning circuit. We will describe a microfabr......Hysteresis has always been one of the main concerns when fabricating touch mode capacitive pressure sensors (TMCPS). This phenomenon can be fought at two different levels: during fabrication or after fabrication with the aid of a dedicated signal conditioning circuit. We will describe...... in the touch mode region....

  15. Altered Neutrophil Function in Localized Juvenile Periodontitis: Intrinsic or Induced?

    Science.gov (United States)

    Agarwal, Sudha; Huang, Jian Ping; Piesco, Nicholas P; Suzuki, Jon B; Riccelli, Angelina E; Johns, Lee P

    1996-03-01

    Localized juvenile periodontitis (LJP) is an aggressive periodontal disease of familial nature. Neutrophils from a majority of patients with this disease exhibit decreased Chemotaxis with increased adherence, oxidative burst, and degranulation in response to opsonized bacteria. It is proposed that the biological basis for these altered neutrophil functions in LJP may be due either to intrinsic cell abnormalities or to the effect of factors present in the sera of LJP patients, which can modulate neutrophil functions. LJP neutrophils exhibit a lower number of receptors for chemoattractants and GP-110 molecules which are known to facilitate Chemotaxis. Furthermore, these cells exhibit lower signal transduction in response to a biological stimulus. These observations suggest that intrinsic cellular defects may be responsible for altered neutrophil functions in LJP. However, healthy neutrophils, when treated with very low concentrations of proinflammatory cytokines, also exhibit the characteristics of altered or "defective" LJP neutrophils. Additionally, healthy neutrophils, when treated with LJP serum, also exhibit many of the characteristics associated with LJP neutrophils. Attempts to identify these factors have shown that cytokines like TNF-α and/or IL1 β in LJP sera may be at least partially responsible for modulating neutrophil functions in LJP. These cytokines are primarily produced by activated macrophages, indicating a role for these cells in the etiology of LJP. The hyper-responsiveness of these cells to an immunologic challenge can result in local increases in cytokines leading to excessive bone loss and tissue damage at the site of infection, while systemic elevations in cytokines would lead to decreased neutrophil Chemotaxis, both of which are observed in LJP. Present evidence indicates that neutrophil functions are indeed altered in the majority of LJP patients. However, the biological basis for the alteration may not be due to the neutrophils themselves

  16. Intrinsic pressure response of a single mode cyclo olefin polymer fiber bragg grating

    DEFF Research Database (Denmark)

    Pedersen, Jens Kristian Mølgaard; Woyessa, Getinet; Nielsen, Kristian

    2016-01-01

    The intrinsic pressure response of a Fibre Bragg Grating (FBG) inscribed in a single-mode cyclo olefin polymer (COP) microstructured polymer optical fibre (mPOF) in the range 0-200 bar is investigated for the first time. In order to efficiently suppress the effects from changes in temperature...

  17. Hydrogen local vibrational modes in semiconductors

    Energy Technology Data Exchange (ETDEWEB)

    McCluskey, Matthew D. [Univ. of California, Berkeley, CA (United States). Dept. of Physics

    1997-06-01

    Following, a review of experimental techniques, theory, and previous work, the results of local vibrational mode (LVM) spectroscopy on hydrogen-related complexes in several different semiconductors are discussed. Hydrogen is introduced either by annealing in a hydrogen ambient. exposure to a hydrogen plasma, or during growth. The hydrogen passivates donors and acceptors in semiconductors, forming neutral complexes. When deuterium is substituted for hydrogen. the frequency of the LVM decreases by approximately the square root of two. By varying the temperature and pressure of the samples, the microscopic structures of hydrogen-related complexes are determined. For group II acceptor-hydrogen complexes in GaAs, InP, and GaP, hydrogen binds to the host anion in a bond-centered orientation, along the [111] direction, adjacent to the acceptor. The temperature dependent shift of the LVMs are proportional to the lattice thermal energy U(T), a consequence of anharmonic coupling between the LVM and acoustical phonons. In the wide band gap semiconductor ZnSe, epilayers grown by metalorganic chemical vapor phase epitaxy (MOCVD) and doped with As form As-H complexes. The hydrogen assumes a bond-centered orientation, adjacent to a host Zn. In AlSb, the DX centers Se and Te are passivated by hydrogen. The second, third, and fourth harmonics of the wag modes are observed. Although the Se-D complex has only one stretch mode, the Se-H stretch mode splits into three peaks. The anomalous splitting is explained by a new interaction between the stretch LVM and multi-phonon modes of the lattice. As the temperature or pressure is varied, and anti-crossing is observed between LVM and phonon modes.

  18. Hydrogen local vibrational modes in semiconductors

    Science.gov (United States)

    McCluskey, Matthew Douglas

    Following a review of experimental techniques, theory, and previous work, the results of local vibrational mode (LVM) spectroscopy on hydrogen-related complexes in several different semiconductors are discussed. Hydrogen is introduced either by annealing in a hydrogen ambient, exposure to a hydrogen plasma, or during growth. The hydrogen passivates donors and acceptors in semiconductors, forming neutral complexes. When deuterium is substituted for hydrogen, the frequency of the LVM decreases by approximately the square root of two. By varying the temperature and pressure of the samples, the microscopic structures of hydrogen-related complexes are determined. For group II acceptor-hydrogen complexes in GaAs, InP, and GaP, hydrogen binds to the host anion in a bond-centered orientation, along the (111) direction, adjacent to the acceptor. The temperature dependent shift of the LVMs are proportional to the lattice thermal energy U(T), a consequence of anharmonic coupling between the LVM and acoustical phonons. In the wide band gap semiconductor ZnSe, epilayers grown by metalorganic chemical vapor phase epitaxy (MOCVD) and doped with As form As-H complexes. The hydrogen assumes a bond-centered orientation, adjacent to a host Zn. In AlSb, the DX centers Se and Te are passivated by hydrogen. The second, third, and fourth harmonics of the wag modes are observed. Although the Se-D complex has only one stretch mode, the Se-H stretch mode splits into three peaks. The anomalous splitting is explained by a new interaction between the stretch LVM and multi-phonon modes of the lattice. As the temperature or pressure is varied, an anti-crossing is observed between the LVM and phonon modes.

  19. Estimation of the intrinsic stresses in α-alumina in relation with its elaboration mode

    International Nuclear Information System (INIS)

    Boumaza, A.; Djelloul, A.

    2010-01-01

    The specific signatures of α-Al 2 O 3 by Fourier transform infrared (FTIR) spectroscopy were investigated to estimate the intrinsic stress in this compound according to its elaboration mode. Thus, α-alumina was prepared either by calcination of boehmite or gibbsite and also generated by oxidation of a metallic FeCrAl alloy. FTIR results were mainly supported by X-ray diffraction (XRD) patterns that allowed to determine the crystallite size and the strain in the various alpha aluminas. Moreover, the infrared peak at 378.7 cm -1 was used as a reference for stress free α-alumina and the shift of this peak allowed to estimate intrinsic stresses, which were related to the morphology and to the specific surface area of aluminas according to their elaboration mode. These interpretations were confirmed by results obtained by cathodoluminescence experiments. - Graphical abstract: The infrared peak at 378.7 cm -1 was used as a reference for stress free α-alumina and the shift of this peak allowed to estimate intrinsic stresses, which were related to the morphology and to the specific surface area of aluminas according to their elaboration mode.

  20. Relation between Protein Intrinsic Normal Mode Weights and Pre-Existing Conformer Populations.

    Science.gov (United States)

    Ozgur, Beytullah; Ozdemir, E Sila; Gursoy, Attila; Keskin, Ozlem

    2017-04-20

    Intrinsic fluctuations of a protein enable it to sample a large repertoire of conformers including the open and closed forms. These distinct forms of the protein called conformational substates pre-exist together in equilibrium as an ensemble independent from its ligands. The role of ligand might be simply to alter the equilibrium toward the most appropriate form for binding. Normal mode analysis is proved to be useful in identifying the directions of conformational changes between substates. In this study, we demonstrate that the ratios of normalized weights of a few normal modes driving the protein between its substates can give insights about the ratios of kinetic conversion rates of the substates, although a direct relation between the eigenvalues and kinetic conversion rates or populations of each substate could not be observed. The correlation between the normalized mode weight ratios and the kinetic rate ratios is around 83% on a set of 11 non-enzyme proteins and around 59% on a set of 17 enzymes. The results are suggestive that mode motions carry intrinsic relations with thermodynamics and kinetics of the proteins.

  1. Magnetic X-points, edge localized modes, and stochasticity

    International Nuclear Information System (INIS)

    Sugiyama, L. E.; Strauss, H. R.

    2010-01-01

    Edge localized modes (ELMs) near the boundary of a high temperature, magnetically confined toroidal plasma represent a new type of nonlinear magnetohydrodynamic (MHD) plasma instability that grows through a coherent plasma interaction with part of a chaotic magnetic field. Under perturbation, the freely moving magnetic boundary surface with an X-point splits into two different limiting asymptotic surfaces (manifolds), similar to the behavior of a hyperbolic saddle point in Hamiltonian dynamics. Numerical simulation using the extended MHD code M3D shows that field-aligned plasma instabilities, such as ballooning modes, can couple to the ''unstable'' manifold that forms helical, field-following lobes around the original surface. Large type I ELMs proceed in stages. Initially, a rapidly growing ballooning outburst involves the entire outboard side. Large plasma fingers grow well off the midplane, while low density regions penetrate deeply into the plasma. The magnetic field becomes superficially stochastic. A secondary inboard edge instability causes inboard plasma loss. The plasma gradually relaxes back toward axisymmetry, with diminishing cycles of edge instability. Poloidal rotation of the interior and edge plasma may be driven. The magnetic tangle constrains the early nonlinear ballooning, but may encourage the later inward penetration. Equilibrium toroidal rotation and two-fluid diamagnetic drifts have relatively small effects on a strong MHD instability. Intrinsic magnetic stochasticity may help explain the wide range of experimentally observed ELMs and ELM-free behavior in fusion plasmas, as well as properties of the H-mode and plasma edge.

  2. Somatostatin receptors in rat hippocampus: localization to intrinsic neurons

    International Nuclear Information System (INIS)

    Palacios, J.M.; Reubi, J.C.; Maurer, R.

    1986-01-01

    The effect of neurotoxic chemical and electrolytical lesions on somatostatin (SS) receptor binding in the septo-hippocampal afferents, pyramidal and granule cells of the rat hippocampus was examined by autoradiography using the stable SS analogue 125 I-204-090 as radioligand. Electrolytical lesions of the septum did not result in modification of SS binding in the hippocampus. In contrast, both granule cell lesion with colchicine and pyramidal or pyramidal and granule cell lesions with increasing kainic acid doses did result in a specific decrease of binding in the dentate gyrus and hippocampus (CA 1 and CA 3 ). These results suggest that SS receptors in the hippocampus are probably associated with elements from intrinsic neurons. (Author)

  3. Intrinsic default mode network connectivity predicts spontaneous verbal descriptions of autobiographical memories during social processing

    Directory of Open Access Journals (Sweden)

    Xiao-Fei eYang

    2013-01-01

    Full Text Available Neural systems activated in a coordinated way during rest, known as the default mode network (DMN, also support autobiographical memory (AM retrieval and social processing/mentalizing. However, little is known about how individual variability in reliance on personal memories during social processing relates to individual differences in DMN functioning during rest (intrinsic functional connectivity. Here we examined 18 participants’ spontaneous descriptions of autobiographical memories during a two-hour, private, open-ended interview in which they reacted to a series of true stories about real people’s social situations and responded to the prompt, how does this person’s story make you feel? We classified these descriptions as either containing factual information (semantic AMs or more elaborate descriptions of emotionally meaningful events (episodic AMs. We also collected resting state fMRI scans from the participants and related individual differences in frequency of described AMs to participants’ intrinsic functional connectivity within regions of the DMN. We found that producing more descriptions of either memory type correlated with stronger intrinsic connectivity in the parahippocampal and middle temporal gyri. Additionally, episodic AM descriptions correlated with connectivity in the bilateral hippocampi and medial prefrontal cortex, and semantic memory descriptions correlated with connectivity in right inferior lateral parietal cortex. These findings suggest that in individuals who naturally invoke more memories during social processing, brain regions involved in memory retrieval and self/social processing are more strongly coupled to the DMN during rest.

  4. Intrinsic Default Mode Network Connectivity Predicts Spontaneous Verbal Descriptions of Autobiographical Memories during Social Processing.

    Science.gov (United States)

    Yang, Xiao-Fei; Bossmann, Julia; Schiffhauer, Birte; Jordan, Matthew; Immordino-Yang, Mary Helen

    2012-01-01

    Neural systems activated in a coordinated way during rest, known as the default mode network (DMN), also support autobiographical memory (AM) retrieval and social processing/mentalizing. However, little is known about how individual variability in reliance on personal memories during social processing relates to individual differences in DMN functioning during rest (intrinsic functional connectivity). Here we examined 18 participants' spontaneous descriptions of autobiographical memories during a 2 h, private, open-ended interview in which they reacted to a series of true stories about real people's social situations and responded to the prompt, "how does this person's story make you feel?" We classified these descriptions as either containing factual information ("semantic" AMs) or more elaborate descriptions of emotionally meaningful events ("episodic" AMs). We also collected resting state fMRI scans from the participants and related individual differences in frequency of described AMs to participants' intrinsic functional connectivity within regions of the DMN. We found that producing more descriptions of either memory type correlated with stronger intrinsic connectivity in the parahippocampal and middle temporal gyri. Additionally, episodic AM descriptions correlated with connectivity in the bilateral hippocampi and medial prefrontal cortex, and semantic memory descriptions correlated with connectivity in right inferior lateral parietal cortex. These findings suggest that in individuals who naturally invoke more memories during social processing, brain regions involved in memory retrieval and self/social processing are more strongly coupled to the DMN during rest.

  5. Mindfulness is associated with intrinsic functional connectivity between default mode and salience networks

    Science.gov (United States)

    Doll, Anselm; Hölzel, Britta K.; Boucard, Christine C.; Wohlschläger, Afra M.; Sorg, Christian

    2015-01-01

    Mindfulness is attention to present moment experience without judgment. Mindfulness practice is associated with brain activity in areas overlapping with the default mode, salience, and central executive networks (DMN, SN, CEN). We hypothesized that intrinsic functional connectivity (iFC; i.e., synchronized ongoing activity) across these networks is associated with mindfulness scores. After 2 weeks of daily 20 min attention to breath training, healthy participants were assessed by mindfulness questionnaires and resting-state functional MRI. Independent component analysis (ICA) of imaging data revealed networks of interest, whose activity time series defined inter-network intrinsic functional connectivity (inter-iFC) by temporal correlation. Inter-iFC between subnetworks of the DMN and SN—and inter-iFC between subnetworks of the SN and left CEN at trend—was correlated with mindfulness scores. Additional control analyses about visual networks’ inter-iFC support the specificity of our findings. Results provide evidence that mindfulness is associated with iFC between DMN and SN. Data suggest that ongoing interactions among central intrinsic brain networks link with the ability to attend to current experience without judgment. PMID:26379526

  6. Mental Task Classification Scheme Utilizing Correlation Coefficient Extracted from Interchannel Intrinsic Mode Function

    Directory of Open Access Journals (Sweden)

    Md. Mostafizur Rahman

    2017-01-01

    Full Text Available In view of recent increase of brain computer interface (BCI based applications, the importance of efficient classification of various mental tasks has increased prodigiously nowadays. In order to obtain effective classification, efficient feature extraction scheme is necessary, for which, in the proposed method, the interchannel relationship among electroencephalogram (EEG data is utilized. It is expected that the correlation obtained from different combination of channels will be different for different mental tasks, which can be exploited to extract distinctive feature. The empirical mode decomposition (EMD technique is employed on a test EEG signal obtained from a channel, which provides a number of intrinsic mode functions (IMFs, and correlation coefficient is extracted from interchannel IMF data. Simultaneously, different statistical features are also obtained from each IMF. Finally, the feature matrix is formed utilizing interchannel correlation features and intrachannel statistical features of the selected IMFs of EEG signal. Different kernels of the support vector machine (SVM classifier are used to carry out the classification task. An EEG dataset containing ten different combinations of five different mental tasks is utilized to demonstrate the classification performance and a very high level of accuracy is achieved by the proposed scheme compared to existing methods.

  7. Towards automated human gait disease classification using phase space representation of intrinsic mode functions

    Science.gov (United States)

    Pratiher, Sawon; Patra, Sayantani; Pratiher, Souvik

    2017-06-01

    A novel analytical methodology for segregating healthy and neurological disorders from gait patterns is proposed by employing a set of oscillating components called intrinsic mode functions (IMF's). These IMF's are generated by the Empirical Mode Decomposition of the gait time series and the Hilbert transformed analytic signal representation forms the complex plane trace of the elliptical shaped analytic IMFs. The area measure and the relative change in the centroid position of the polygon formed by the Convex Hull of these analytic IMF's are taken as the discriminative features. Classification accuracy of 79.31% with Ensemble learning based Adaboost classifier validates the adequacy of the proposed methodology for a computer aided diagnostic (CAD) system for gait pattern identification. Also, the efficacy of several potential biomarkers like Bandwidth of Amplitude Modulation and Frequency Modulation IMF's and it's Mean Frequency from the Fourier-Bessel expansion from each of these analytic IMF's has been discussed for its potency in diagnosis of gait pattern identification and classification.

  8. Study on the relationships between intrinsic functional connectivity of the default mode network and transient epileptic activity

    Directory of Open Access Journals (Sweden)

    Renaud eLopes

    2014-10-01

    Full Text Available Rationale. Simultaneous recording of electroencephalogram and functional MRI (EEG-fMRI is a powerful tool for localizing epileptic networks via the detection of hemodynamic changes correlated with interictal epileptic discharges (IEDs. FMRI can be used to study the long-lasting effect of epileptic activity by assessing stationary functional connectivity during the resting-state period (especially the connectivity of the default mode network (DMN. Temporal lobe epilepsy (TLE and idiopathic generalized epilepsy (IGE are associated with low responsiveness and disruption of DMN activity. A dynamic functional connectivity approach might enable us to determine the effect of IEDs on DMN connectivity and to better understand the correlation between DMN connectivity changes and altered consciousness. Method. We studied dynamic changes in DMN intrinsic connectivity and their relation to IEDs. Six IGE patients (with generalized spike and slow waves and 6 TLE patients (with unilateral left temporal spikes were included. Functional connectivity before, during and after IEDs was estimated using a sliding window approach and compared with the baseline period.Results. No dependence on window size was observed. The baseline DMN connectivity was decreased in the left hemisphere (ipsilateral to the epileptic focus in TLEs and was less strong but remained bilateral in IGEs. We observed an overall increase in DMN intrinsic connectivity prior to the onset of IEDs in both IGEs and TLEs. After IEDs in TLEs, we found that DMN connectivity increased before it returned to baseline values. Most of the DMN regions with increased connectivity before and after IEDs were lateralized to the left hemisphere in TLE (i.e., ipsilateral to the epileptic focus.Conclusion. Results suggest that DMN connectivity may facilitate IED generation and may be affected at the time of the IED. However, these results need to be confirmed in a larger independent cohort.

  9. Localized radio frequency communication using asynchronous transfer mode protocol

    Science.gov (United States)

    Witzke, Edward L.; Robertson, Perry J.; Pierson, Lyndon G.

    2007-08-14

    A localized wireless communication system for communication between a plurality of circuit boards, and between electronic components on the circuit boards. Transceivers are located on each circuit board and electronic component. The transceivers communicate with one another over spread spectrum radio frequencies. An asynchronous transfer mode protocol controls communication flow with asynchronous transfer mode switches located on the circuit boards.

  10. Low-frequency variability of Western Boundary Currents in the turbulent ocean: intrinsic modes and atmospheric forcing

    Science.gov (United States)

    Sérazin, Guillaume; Penduff, Thierry; Terray, Laurent; Grégorio, Sandy; Barnier, Bernard; Molines, Jean-Marc

    2015-04-01

    Ocean-atmosphere heat fluxes are particularly strong in Western Boundary Current (WBC) regions where SST front variations influence basin-scale climate variability. Observed low-frequency fluctuations in latitude and strength of these oceanic jets are classically thought to be essentially atmospherically-driven by wind stress curl variability via the oceanic Rossby wave adjustment. Yet academic eddy-resolving process-oriented models with double-gyre configurations have revealed that an idealized WBC may exhibit low-frequency intrinsic fluctuations without low-frequency external forcing (e.g. Berloff et al., 2007, Dijkstra and Ghil, 2005, etc). Experiments with eddying Ocean General Circulation Models (OGCMs) have also shown that the amount of low-frequency Sea Level Anomaly (SLA) variability is largely intrinsic in WBCs (Penduff et al. 2011; Sérazin et al 2014) and that the frontal-scale (performed on zonally-averaged SLA fields of four main WBCs (e.g. Gulf Stream, Kuroshio Extension, Agulhas Current and East Australian Current). The first two modes of the KE and GS exhibit a similar spatial structure that is shaped by oceanic intrinsic processes. The frequency content is however different between the intrinsic and total Principal Components, the former containing a wide range of timescales similar to a red noise and the latter being more autocorrelated at interannual-to-decadal timescales. These modes are compared with those obtained from the 20 years of altimetry observation and relationships with low-frequency westward propagative features in the respective oceanic basin are investigated. We argue that OGCM studies of intrinsic dynamic of WBCs are key to interpreting their observed total variability, which might result from a subtle mixing between a non-linear small-scale response of intrinsic modes to the atmospheric forcing and a direct basin-scale linear response to the atmosphere.

  11. Local effect of equilibrium current on tearing mode stability

    International Nuclear Information System (INIS)

    Cozzani, F.

    1985-12-01

    The local effect of the equilibrium current on the linear stability of low poloidal number tearing modes in tokamaks is investigated analytically. The plasma response inside the tearing layer is derived from fluid theory and the local equilibrium current is shown to couple to the mode dynamics through its gradient, which is proportional to the local electron temperature gradient under the approximations used in the analysis. The relevant eigenmode equations, expressing Ampere's law and the plasma quasineutrality condition, respectively, are suitably combined in a single integral equation, from which a variational principle is formulated to derive the mode dispersion relations for several cases of interest. The local equilibrium current is treated as a small perturbation of the known results for the m greater than or equal to 2 and the m = 1 tearing modes in the collisional regime, and the m greater than or equal to 2 tearing mode in the semicollisional regime; its effect is found to enhance stabilization for the m greater than or equal to 2 drift-tearing mode in the collisional regime, whereas the m = 1 growth rate is very slightly increased and the stabilizing effect of the parallel thermal conduction on the m greater than or equal to 2 mode in the semicollisional regime is slightly reduced

  12. Pipe leak diagnostic using high frequency piezoelectric pressure sensor and automatic selection of intrinsic mode function

    Science.gov (United States)

    Yusop, Hanafi M.; Ghazali, M. F.; Yusof, M. F. M.; Remli, M. A. Pi; Kamarulzaman, M. H.

    2017-10-01

    In a recent study, the analysis of pressure transient signals could be seen as an accurate and low-cost method for leak and feature detection in water distribution systems. Transient phenomena occurs due to sudden changes in the fluid’s propagation in pipelines system caused by rapid pressure and flow fluctuation due to events such as closing and opening valves rapidly or through pump failure. In this paper, the feasibility of the Hilbert-Huang transform (HHT) method/technique in analysing the pressure transient signals in presented and discussed. HHT is a way to decompose a signal into intrinsic mode functions (IMF). However, the advantage of HHT is its difficulty in selecting the suitable IMF for the next data postprocessing method which is Hilbert Transform (HT). This paper reveals that utilizing the application of an integrated kurtosis-based algorithm for a z-filter technique (I-Kaz) to kurtosis ratio (I-Kaz-Kurtosis) allows/contributes to/leads to automatic selection of the IMF that should be used. This technique is demonstrated on a 57.90-meter medium high-density polyethylene (MDPE) pipe installed with a single artificial leak. The analysis results using the I-Kaz-kurtosis ratio revealed/confirmed that the method can be used as an automatic selection of the IMF although the noise level ratio of the signal is low. Therefore, the I-Kaz-kurtosis ratio method is recommended as a means to implement an automatic selection technique of the IMF for HHT analysis.

  13. Modulational instability and localized modes in Heisenberg ferromagnetic chains with single-ion easy-axis anisotropy

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Bing, E-mail: bingtangphy@jsu.edu.cn; Li, Guang-Ling; Fu, Mei

    2017-03-15

    A semiclassical theoretical study on the property of the modulational instability of corresponding linear spin-waves and the presence of nonlinear localized excitations in a discrete quantum ferromagnetic spin chain with single-ion easy-axis anisotropy is reported. We consider the Glauber coherent-state representation combined with the Dyson-Maleev transformation for local spin operators as the basic representation of the system, and derive the equation of motion by means of the Ehrenfest theorem. Using a modulational instability analysis of plane waves, we predict the existence regions of bright envelope solitons and intrinsic localized spin-wave modes. Besides, with the help of a semidiscrete multi-scale method, we obtain analytical solutions for the bright envelope soliton and intrinsic localized spin-wave mode. Moreover, we analyze their existence conditions, which agree with the results of modulational instability analysis. - Highlights: • The anisotropy plays significant role in both the property of the modulational instability and the existence conditions for localized modes in ferromagnetic chains. • The analytical solutions of localized modes are obtained. • The appearance conditions for such localized modes agree with the modulational instability analysis.

  14. Entropy squeezing for a two-level atom in two-mode Raman coupled model with intrinsic decoherence

    International Nuclear Information System (INIS)

    Jian, Zhang; Bin, Shao; Jian, Zou

    2009-01-01

    In this paper, we investigate the entropy squeezing for a two-level atom interacting with two quantized fields through Raman coupling. We obtain the dynamical evolution of the total system under the influence of intrinsic decoherence when the two quantized fields are prepared in a two-mode squeezing vacuum state initially. The effects of the field squeezing factor, the two-level atomic transition frequency, the second field frequency and the intrinsic decoherence on the entropy squeezing are discussed. Without intrinsic decoherence, the increase of field squeezing factor can break the entropy squeezing. The two-level atomic transition frequency changes only the period of oscillation but not the strength of entropy squeezing. The influence of the second field frequency is complicated. With the intrinsic decoherence taken into consideration, the results show that the stronger the intrinsic decoherence is, the more quickly the entropy squeezing will disappear. The increase of the atomic transition frequency can hasten the disappearance of entropy squeezing. (classical areas of phenomenology)

  15. Lumped Mass Modeling for Local-Mode-Suppressed Element Connectivity

    DEFF Research Database (Denmark)

    Joung, Young Soo; Yoon, Gil Ho; Kim, Yoon Young

    2005-01-01

    connectivity parameterization (ECP) is employed. On the way to the ultimate crashworthy structure optimization, we are now developing a local mode-free topology optimization formulation that can be implemented in the ECP method. In fact, the local mode-freeing strategy developed here can be also used directly...... experiencing large structural changes, appears to be still poor. In ECP, the nodes of the domain-discretizing elements are connected by zero-length one-dimensional elastic links having varying stiffness. For computational efficiency, every elastic link is now assumed to have two lumped masses at its ends....... Choosing appropriate penalization functions for lumped mass and link stiffness is important for local mode-free results. However, unless the objective and constraint functions are carefully selected, it is difficult to obtain clear black-and-white results. It is shown that the present formulation is also...

  16. Linear local stability of electrostatic drift modes in helical systems

    International Nuclear Information System (INIS)

    Yamagishi, O.; Nakajima, N.; Sugama, H.; Nakamura, Y.

    2003-01-01

    We investigate the stability of the drift wave in helical systems. For this purpose, we solve the linear local gyrokinetic-Poisson equation, in the electrostatic regime. As a model of helical plasmas, Large helical Device (LHD) is considered. The equation we apply is rather exact in the framework of linear gyrokinetic theory, where only the approximation is the ballooning representation. In this paper, we consider only collisionless cases. All the frequency regime can be naturally reated without any assumptions, and in such cases, ion temperature gradient modes (ITG), trapped electron modes (TEM), and electron temperature gradient modes (ETG) are expected to become unstable linearly independently. (orig.)

  17. Edge-localized mode avoidance and pedestal structure in I-mode plasmasa)

    Science.gov (United States)

    Walk, J. R.; Hughes, J. W.; Hubbard, A. E.; Terry, J. L.; Whyte, D. G.; White, A. E.; Baek, S. G.; Reinke, M. L.; Theiler, C.; Churchill, R. M.; Rice, J. E.; Snyder, P. B.; Osborne, T.; Dominguez, A.; Cziegler, I.

    2014-05-01

    I-mode is a high-performance tokamak regime characterized by the formation of a temperature pedestal and enhanced energy confinement, without an accompanying density pedestal or drop in particle and impurity transport. I-mode operation appears to have naturally occurring suppression of large Edge-Localized Modes (ELMs) in addition to its highly favorable scalings of pedestal structure and overall performance. Extensive study of the ELMy H-mode has led to the development of the EPED model, which utilizes calculations of coupled peeling-ballooning MHD modes and kinetic-ballooning mode (KBM) stability limits to predict the pedestal structure preceding an ELM crash. We apply similar tools to the structure and ELM stability of I-mode pedestals. Analysis of I-mode discharges prepared with high-resolution pedestal data from the most recent C-Mod campaign reveals favorable pedestal scalings for extrapolation to large machines—pedestal temperature scales strongly with power per particle Pnet/n ¯e, and likewise pedestal pressure scales as the net heating power (consistent with weak degradation of confinement with heating power). Matched discharges in current, field, and shaping demonstrate the decoupling of energy and particle transport in I-mode, increasing fueling to span nearly a factor of two in density while maintaining matched temperature pedestals with consistent levels of Pnet/n ¯e. This is consistent with targets for increased performance in I-mode, elevating pedestal βp and global performance with matched increases in density and heating power. MHD calculations using the ELITE code indicate that I-mode pedestals are strongly stable to edge peeling-ballooning instabilities. Likewise, numerical modeling of the KBM turbulence onset, as well as scalings of the pedestal width with poloidal beta, indicates that I-mode pedestals are not limited by KBM turbulence—both features identified with the trigger for large ELMs, consistent with the observed suppression of

  18. Characterization of Edge Localized Modes in Tokamak Plasmas

    NARCIS (Netherlands)

    Boom, J. E.

    2012-01-01

    To mimic the fusion of hydrogen nuclei in the sun as an energy source on Earth, fusion scientists have to deal with miniature solar flares in their nuclear fusion reactor. These 'Edge Localized Modes' (ELMs) can damage the wall of the reactor. Physicist Jurrian Boom from the FOM Institute

  19. Localized tearing modes in the magnetotail driven by curvature effects

    Energy Technology Data Exchange (ETDEWEB)

    Sundaram, A.K.; Fairfield, D.H. [NASA Goddard Space Flight Center, Greenbelt, MD (United States)

    1995-03-01

    The stability of collisionless tearing modes is examined in the presence of curvature drift resonances and the trapped particle effects. A kinetic description for both electrons and ions is employed to investigate the stability of a two-dimensional equilibrium model. The main features of the study are to treat the ion dynamics properly by incorporating effects associated with particle trajectories in the tail fields and to include the linear coupling of trapped particle modes. Generalized dispersion relations are derived in several parameter regimes by considering two important sublayers of the reconnecting region. For a typical choice of parameters appropriate to the current sheet region, the authors demonstrate that localized tearing modes driven by ion curvature drift resonance effects are excited in the current sheet region with growth time of the order of a few seconds. Also, they examine nonlocal characteristics of tearing modes driven by curvature effects and show that modes growing in a fraction of a second arise when mode widths are larger than the current sheet width. Further, they show that trapped particle effects, in an interesting frequency regime, significantly enhance the growth rate of the tearing mode. The relevance of this theory for substorm onset phase and other features of the substorms is briefly discussed. 38 refs.

  20. Intrinsic Compressive Stress in Polycrystalline Films is Localized at Edges of the Grain Boundaries

    Science.gov (United States)

    Vasco, Enrique; Polop, Celia

    2017-12-01

    The intrinsic compression that arises in polycrystalline thin films under high atomic mobility conditions has been attributed to the insertion or trapping of adatoms inside grain boundaries. This compression is a consequence of the stress field resulting from imperfections in the solid and causes the thermomechanical fatigue that is estimated to be responsible for 90% of mechanical failures in current devices. We directly measure the local distribution of residual intrinsic stress in polycrystalline thin films on nanometer scales, using a pioneering method based on atomic force microscopy. Our results demonstrate that, at odds with expectations, compression is not generated inside grain boundaries but at the edges of gaps where the boundaries intercept the surface. We describe a model wherein this compressive stress is caused by Mullins-type surface diffusion towards the boundaries, generating a kinetic surface profile different from the mechanical equilibrium profile by the Laplace-Young equation. Where the curvatures of both profiles differ, an intrinsic stress is generated in the form of Laplace pressure. The Srolovitz-type surface diffusion that results from the stress counters the Mullins-type diffusion and stabilizes the kinetic surface profile, giving rise to a steady compression regime. The proposed mechanism of competition between surface diffusions would explain the flux and time dependency of compressive stress in polycrystalline thin films.

  1. Localization of soft modes at the depinning transition

    Science.gov (United States)

    Cao, Xiangyu; Bouzat, Sebastian; Kolton, Alejandro B.; Rosso, Alberto

    2018-02-01

    We characterize the soft modes of the dynamical matrix at the depinning transition, and compare the matrix with the properties of the Anderson model (and long-range generalizations). The density of states at the edge of the spectrum displays a universal linear tail, different from the Lifshitz tails. The eigenvectors are instead very similar in the two matrix ensembles. We focus on the ground state (soft mode), which represents the epicenter of avalanche instabilities. We expect it to be localized in all finite dimensions, and make a clear connection between its localization length and the Larkin length of the depinning model. In the fully connected model, we show that the weak-strong pinning transition coincides with a peculiar localization transition of the ground state.

  2. Nanoscale scanning probe ferromagnetic resonance imaging using localized modes.

    Science.gov (United States)

    Lee, Inhee; Obukhov, Yuri; Xiang, Gang; Hauser, Adam; Yang, Fengyuan; Banerjee, Palash; Pelekhov, Denis V; Hammel, P Chris

    2010-08-12

    The discovery of new phenomena in layered and nanostructured magnetic devices is driving rapid growth in nanomagnetics research. Resulting applications such as giant magnetoresistive field sensors and spin torque devices are fuelling advances in information and communications technology, magnetoelectronic sensing and biomedicine. There is an urgent need for high-resolution magnetic-imaging tools capable of characterizing these complex, often buried, nanoscale structures. Conventional ferromagnetic resonance (FMR) provides quantitative information about ferromagnetic materials and interacting multicomponent magnetic structures with spectroscopic precision and can distinguish components of complex bulk samples through their distinctive spectroscopic features. However, it lacks the sensitivity to probe nanoscale volumes and has no imaging capabilities. Here we demonstrate FMR imaging through spin-wave localization. Although the strong interactions in a ferromagnet favour the excitation of extended collective modes, we show that the intense, spatially confined magnetic field of the micromagnetic probe tip used in FMR force microscopy can be used to localize the FMR mode immediately beneath the probe. We demonstrate FMR modes localized within volumes having 200 nm lateral dimensions, and improvements of the approach may allow these dimensions to be decreased to tens of nanometres. Our study shows that this approach is capable of providing the microscopic detail required for the characterization of ferromagnets used in fields ranging from spintronics to biomagnetism. This method is applicable to buried and surface magnets, and, being a resonance technique, measures local internal fields and other magnetic properties with spectroscopic precision.

  3. Intrinsic and doped coupled quantum dots created by local modulation of implantation in a silicon nanowire

    Science.gov (United States)

    Pierre, M.; Roche, B.; Wacquez, R.; Jehl, X.; Sanquer, M.; Vinet, M.

    2011-04-01

    We present a systematic study of various ways (top gates, local doping, substrate bias) to fabricate and tune multi-dot structures in silicon nanowire multigate metal-oxide-semiconductor field-effect transistors. The carrier concentration profile of the silicon nanowire is a key parameter to control the formation of tunnel barriers and single-electron islands. It is determined both by the doping profile of the nanowire and by the voltages applied to the top gates and to the substrate. Local doping is achieved with the realization of up to two arsenic implantation steps in combination with gates and nitride spacers acting as a mask. We compare nominally identical devices with different implantations and different voltages applied to the substrate, leading to the realization of both intrinsic and doped coupled dot structures. We demonstrate devices in which all the tunnel resistances toward the electrodes and between the dots can be independently tuned with the control top gates wrapping the silicon nanowire.

  4. Edge localized mode rotation and the nonlinear dynamics of filaments

    Czech Academy of Sciences Publication Activity Database

    Morales, J.A.; Bécoulet, M.; Garbet, X.; Orain, F.; Dif-Pradalier, G.; Hoelzl, M.; Pamela, S.; Huijsmans, G.T.A.; Cahyna, Pavel; Fil, A.; Nardon, E.; Passeron, C.; Latu, G.

    2016-01-01

    Roč. 23, č. 4 (2016), č. článku 042513. ISSN 1070-664X EU Projects: European Commission(XE) 633053 - EUROfusion Institutional support: RVO:61389021 Keywords : Edge Localized Modes (ELMs) * MHD * tokamak * ITER Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.115, year: 2016 http://scitation.aip.org/content/aip/journal/pop/23/4/10.1063/1.4947201

  5. Edge localized mode rotation and the nonlinear dynamics of filaments

    Czech Academy of Sciences Publication Activity Database

    Morales, J.A.; Bécoulet, M.; Garbet, X.; Orain, F.; Dif-Pradalier, G.; Hoelzl, M.; Pamela, S.; Huijsmans, G.T.A.; Cahyna, Pavel; Fil, A.; Nardon, E.; Passeron, C.; Latu, G.

    2016-01-01

    Roč. 23, č. 4 (2016), č. článku 042513. ISSN 1070-664X EU Projects: European Commission(XE) 633053 - EUROfusion Institutional support: RVO:61389021 Keywords : Edge Localized Modes (ELMs) * MHD * tokamak * ITER Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.115, year: 2016 http://scitation.aip.org/content/aip/journal/ pop /23/4/10.1063/1.4947201

  6. Anisotropy of Earth's inner core intrinsic attenuation from seismic normal mode models

    NARCIS (Netherlands)

    Mäkinen, Anna M.; Deuss, Arwen; Redfern, Simon A T

    2014-01-01

    The Earth's inner core, the slowly growing sphere of solid iron alloy at the centre of our planet, is known to exhibit seismic anisotropy. Both normal mode and body wave studies have established that, when the global average is taken, compressional waves propagate faster in the North-South direction

  7. The effect of intrinsic instability of cantilever on static mode atomic force spectroscopy.

    Science.gov (United States)

    Das, Soma; Raychaudhuri, A K; Sreeram, P A; Dietzel, Dirk

    2010-01-29

    We show that the static force spectroscopy curve taken in an atomic force microscope is significantly modified due to presence of intrinsic cantilever instability which occurs as a result of its movement in a nonlinear force field. This instability acts in tandem with such instabilities as water bridge or molecular bond rupture and makes the static force spectroscopy curve (including 'jump-off-contact') dependent on the step size of data collection. A theoretical model has been proposed to explain the data. We emphasize the necessity of taking care of this fundamental instability of the microcantilever in calculating the adhesive force and also in the interpretation of data taken using an atomic force microscope.

  8. Correlation between Traits of Emotion-Based Impulsivity and Intrinsic Default-Mode Network Activity

    Directory of Open Access Journals (Sweden)

    Jizheng Zhao

    2017-01-01

    Full Text Available Negative urgency (NU and positive urgency (PU are implicated in several high-risk behaviors, such as eating disorders, substance use disorders, and nonsuicidal self-injury behavior. The current study aimed to explore the possible link between trait of urgency and brain activity at rest. We assessed the amplitude of low-frequency fluctuations (ALFF of the resting-state functional magnetic resonance imaging (fMRI signal in 85 healthy volunteers. Trait urgency measures were related to ALFF in the lateral orbitofrontal cortex, dorsolateral prefrontal cortex, ventral and dorsal medial frontal cortex, anterior cingulate, and posterior cingulate cortex/precuneus. In addition, trait urgency measures showed significant correlations with the functional connectivity of the posterior cingulate cortex/precuneus seed with the thalamus and midbrain region. These findings suggest an association between intrinsic brain activity and impulsive behaviors in healthy humans.

  9. Intrinsic dendritic filtering gives low-pass power spectra of local field potentials

    DEFF Research Database (Denmark)

    Lindén, Henrik; Pettersen, Klas H; Einevoll, Gaute T

    2010-01-01

    The local field potential (LFP) is among the most important experimental measures when probing neural population activity, but a proper understanding of the link between the underlying neural activity and the LFP signal is still missing. Here we investigate this link by mathematical modeling...... of contributions to the LFP from a single layer-5 pyramidal neuron and a single layer-4 stellate neuron receiving synaptic input. An intrinsic dendritic low-pass filtering effect of the LFP signal, previously demonstrated for extracellular signatures of action potentials, is seen to strongly affect the LFP power...... spectra, even for frequencies as low as 10 Hz for the example pyramidal neuron. Further, the LFP signal is found to depend sensitively on both the recording position and the position of the synaptic input: the LFP power spectra recorded close to the active synapse are typically found to be less low...

  10. Characteristics of edge localized mode in JFT-2M H-mode

    International Nuclear Information System (INIS)

    Matsumoto, Hiroshi; Funahashi, Akimasa; Goldston, R.J.

    1989-03-01

    Characteristics of edge localized mode (ELM/ERP) during H-mode plasma of JFT-2M were investigated. It was found that ELM/ERP is mainly a density fluctuation phenomena in the edge, and electron temperature in the edge except just near the separatrix is not very much perturbed. Several experimental conditions to controll ELM/ERP are, plasma density, plasma ion species, heating power, and plasma current ramping. ELM/ERPs found in low density deuterium discharge are suppressed by raising the density. ELM/ERPs are pronounced in hydrogen plasma compared with deuterium plasma. ELM/ERPs seen in hydrogen plasma or in near marginal H-mode conditions are suppressed by increasing the heating power. ELM/ERPs are found to be suppressed by plasma current ramp down, whereas they are enhanced by current ramp up. MHD aspect of ELM/ERP was investigated. No clear MHD features of ELM/ERP were found. However, reversal of mode rotation seen imediately after ELM/ERP suggests the temporal return to L-mode during the ELM/ERP event. (author)

  11. Edge localized modes of cold neutrons in periodic condensed media

    Science.gov (United States)

    Belyakov, V. A.

    2017-06-01

    It is found that for certain energies of discreet cold neutrons, quasi-stationary eigen solutions of the corresponding Schrodinger equation, which are localized in the layer of a periodic medium, exist. The localization time of these solutions is strongly dependent on the layer thickness, being finite for a finite layer thickness and increasing indefinitely upon a infinite growth of the layer thickness as the third power of the layer thickness. The problem has been solved in the two-wave approximation of the dynamic diffraction theory for the neutron propagation direction coinciding with the periodicity axes (normal incidence of the neutron beam on the layer). The expressions for neutron eigenwave functions in a periodic medium, the reflection and transmission coefficients, and the neutron wavefunction in the layer as a function of the neutron energy incident on the layer have been determined. It turns out that for the certain discrete neutron energies, the amplitudes of the neutron wavefunction in the layer reach sharp maxima. The corresponding energies are just outside of the neutron stop band (energies forbidden for neutron propagation in the layer) and determine the energies of neutron edge modes (NEMs) localized in the layer, which are direct analogs of the optical edge modes for photonic crystals. The dispersion equation for the localized neutron edge modes has been obtained and analytically solved for the case of thick layers. A rough estimate for the localization length L is L ( db N)-1, where b is the neutron scattering length, d is the crystal period, and N is the density of nuclei in the crystal. The estimates of the localized thermal neutron lifetime show that acheaving of a lifetime close to the free neutron lifetime seems nonrealistic due to absorption of thermal neutrons and requires a perfect large size crystal. Nevertheless, acheaving the localized neutron lifetime exceeding by 104 times the neutron time of flight through the layer appears as

  12. A local cubic smoothing in an adaptation mode

    International Nuclear Information System (INIS)

    Dikoussar, N.D.

    2001-01-01

    A new approach to a local curve approximation and the smoothing is proposed. The relation between curve points is defined using a special cross-ratio weight functions. The coordinates of three curve points are used as parameters for both the weight functions and the tree-point cubic model (TPS). A very simple in computing and stable to random errors cubic smoother in an adaptation mode (LOCUS) is constructed. The free parameter of TPS is estimated independently of the fixed parameters by recursion with the effective error suppression and can be controlled by the cross-ratio parameters. Efficiency and the noise stability of the algorithm are confirmed by examples and by comparison with other known non-parametric smoothers

  13. Localized surface plate modes via flexural Mie resonances

    KAUST Repository

    Farhat, M.

    2017-05-11

    Surface-plasmon polaritons are naturally generated upon excitation of metals with high-frequency electromagnetic waves. However, the concept of spoof plasmons has made it possible to generate plasmoniclike effects in microwave electrodynamics, magnetics, and even acoustics. Similarly, in this paper, the concept of localized surface plate modes (SPMs) is introduced. It is demonstrated that SPMs can be generated on a two-dimensional (clamped or stress-free) cylindrical surface with subwavelength corrugations, which resides on a thin elastic plate, under excitation by an incident flexural plane wave. Numerical characterization of this corrugated rigid structure shows that it is elastically equivalent to a cylindrical scatterer with dispersive but uniformly negative flexural rigidity. This, indeed, suggests that plasmoniclike elastic materials can be engineered with potential applications in various areas including earthquake sensing and elastic imaging and cloaking.

  14. The non-linear evolution of edge localized modes

    Energy Technology Data Exchange (ETDEWEB)

    Wenninger, Ronald

    2013-01-09

    Edge localized modes (ELMs) are instabilities in the edge of tokamak plasmas in the high confinement regime (H-mode). Without them the edge transport in ordinary H-mode plasmas is too low to establish a stationary situation. However in a future device large unmitigated ELMs are believed to cause divertor power flux densities far in excess of tolerable material limits. Hence the size of energy loss per ELM and the resulting ELM frequency must be controlled. To proceed in understanding how the ELM size is determined and how ELM mitigation methods work it is necessary to characterize the non-linear evolution of pedestal erosion. In order to achieve this experimental data is compared to the results of ELM simulations with the code JOREK (reduced MHD, non-linear) applying a specially developed synthetic magnetic diagnostic. The experimental data are acquired by several fast sampling diagnostics at the experiments ASDEX Upgrade and TCV at a large number of toroidal/poloidal positions. A central element of the presented work is the detailed characterization of dominant magnetic perturbations during ELMs. These footprints of the instability can be observed most intensely in close temporal vicinity to the onset of pedestal erosion. Dominant magnetic perturbations are caused by current perturbations located at or inside the last closed flux surface. In ASDEX Upgrade under certain conditions dominant magnetic perturbations like other H-mode edge instabilities display a similarity to solitons. Furthermore - as expected - they are often observed to be correlated to a perturbation of electron temperature. In TCV it is possible to characterize the evolution of the toroidal structure of dominant magnetic perturbations. Between growing above the level of background fluctuations and the maximum perturbation level for all time instance a similar toroidal structure is observed. This rigid mode-structure is an indication for non-linear coupling. Most frequently the dominant toroidal

  15. The use of transmission line modelling to test the effectiveness of I-kaz as autonomous selection of intrinsic mode function

    Science.gov (United States)

    Yusop, Hanafi M.; Ghazali, M. F.; Yusof, M. F. M.; PiRemli, M. A.; Karollah, B.; Rusman

    2017-10-01

    Pressure transient signal occurred due to sudden changes in fluid propagation filled in pipelines system, which is caused by rapid pressure and flow fluctuation in a system, such as closing and opening valve rapidly. The application of Hilbert-Huang Transform (HHT) as the method to analyse the pressure transient signal utilised in this research. However, this method has the difficulty in selecting the suitable IMF for the further post-processing, which is Hilbert Transform (HT). This paper proposed the implementation of Integrated Kurtosis-based Algorithm for z-filter Technique (I-kaz) to kurtosis ratio (I-kaz-Kurtosis) for that allows automatic selection of intrinsic mode function (IMF) that’s should be used. This work demonstrated the synthetic pressure transient signal generates using transmission line modelling (TLM) in order to test the effectiveness of I-kaz as the autonomous selection of intrinsic mode function (IMF). A straight fluid network was designed using TLM fixing with higher resistance at some point act as a leak and connecting to the pipe feature (junction, pipefitting or blockage). The analysis results using I-kaz-kurtosis ratio revealed that the method can be utilised as an automatic selection of intrinsic mode function (IMF) although the noise level ratio of the signal is lower. I-kaz-kurtosis ratio is recommended and advised to be implemented as automatic selection of intrinsic mode function (IMF) through HHT analysis.

  16. Local Mode Analysis: Decoding IR Spectra by Visualizing Molecular Details.

    Science.gov (United States)

    Massarczyk, M; Rudack, T; Schlitter, J; Kuhne, J; Kötting, C; Gerwert, K

    2017-04-20

    Integration of experimental and computational approaches to investigate chemical reactions in proteins has proven to be very successful. Experimentally, time-resolved FTIR difference-spectroscopy monitors chemical reactions at atomic detail. To decode detailed structural information encoded in IR spectra, QM/MM calculations are performed. Here, we present a novel method which we call local mode analysis (LMA) for calculating IR spectra and assigning spectral IR-bands on the basis of movements of nuclei and partial charges from just a single QM/MM trajectory. Through LMA the decoding of IR spectra no longer requires several simulations or optimizations. The novel approach correlates the motions of atoms of a single simulation with the corresponding IR bands and provides direct access to the structural information encoded in IR spectra. Either the contributions of a particular atom or atom group to the complete IR spectrum of the molecule are visualized, or an IR-band is selected to visualize the corresponding structural motions. Thus, LMA decodes the detailed information contained in IR spectra and provides an intuitive approach for structural biologists and biochemists. The unique feature of LMA is the bidirectional analysis connecting structural details to spectral features and vice versa spectral features to molecular motions.

  17. Intrinsic Neural Linkage between Primary Visual Area and Default Mode Network in Human Brain: Evidence from Visual Mental Imagery.

    Science.gov (United States)

    Zhang, Zheng; Zhang, Delong; Wang, Zengjian; Li, Junchao; Lin, Yuting; Chang, Song; Huang, Ruiwang; Liu, Ming

    2018-03-08

    Previous studies have reported the essence of the sensory-based properties of human brain function, in which mental imagery is of great importance. In this study, we explored the association between the activities of two special regions, i.e., the primary visual area (PVA), which is the classically dominant sensory region, and the default mode network (DMN), which is the classical supra-sensory region, with a focus on their linkage in visual mental imagery. For this purpose, we collected fMRI data from 30 healthy participants (15 males; 22.37 ± 2.52 years) during the resting state and a mental rotation task state. By using a critical time point analysis (CTPA), we investigated the association between the activities of the PVA and the DMN. As the results showed, there existed a PVA-related (i.e., prefrontal cortex, DMN, sensorimotor areas and medial temporal lobe (MTL)) and a DMN-related neural association pattern (i.e., PVA, prefrontal cortex and the MTL) in the human brain. Furthermore, the results showed the steady and tight intrinsic association between the activities of the PVA and the DMN, with the prefrontal cortex and the MTL regions being found to be consistently involved in the resting-state brain. It also was suggested that the observed association between the PVA and the DMN was highly reproducible for the mental rotation task. Together, these observations, from the perspective of visual mental imagery, provided experimental evidence for the robustness and stability of the detailed map of the associations between the activities of the PVA and the DMN. Copyright © 2018 IBRO. Published by Elsevier Ltd. All rights reserved.

  18. Center deviation of localized modes in a one-dimension anharmonic single impurity chain

    Science.gov (United States)

    Chen, Xuan-Lin; Zhu, Gang-Bei; Jiang, Ze-Hui; Yang, Yan-Qiang

    2018-04-01

    A 1D anharmonic chain with a single impurity particle is used to study the center deviation and stability of the localized modes. The displacement patterns of the localized modes for a variable impurity mass and anharmonic parameter are studied. The pattern center is shifted away from the impurity with decreasing anharmonic parameter for both symmetric and asymmetric anharmonic impurity modes. In the limit of a heavy-mass impurity, the energy localization is constrained to the three particles nearest to the impurity.

  19. Edge localized modes control by resonant magnetic perturbations

    International Nuclear Information System (INIS)

    Nardon, E.

    2007-10-01

    The present work is dedicated to one of the most promising methods of control of the ELMs (Edge Localized Modes), based on a system of coils producing Resonant Magnetic Perturbations (RMPs). Our main objectives are, on the one hand, to improve the physical understanding of the mechanisms at play, and on the other hand to propose a concrete design of ELMs control coils for ITER. In order to calculate and analyze the magnetic perturbations produced by a given set of coils, we have developed the ERGOS code. The first ERGOS calculation was for the DIII-D ELMs control coils, the I-coils. It showed that they produce magnetic islands chains which overlap at the edge of the plasma, resulting in the ergodization of the magnetic field. We have then used ERGOS for the modelling of the experiments on ELMs control using the error field correction coils at JET and MAST. In the case of JET, we have shown the existence of a correlation between the mitigation of the ELMs and the ergodization of the magnetic field at the edge, in agreement with the DIII-D result. In order to design the ELMs control coils for ITER we have used ERGOS intensively, taking the case of the DIII-D I-coils as a reference. Three candidate designs came out, which we presented at the ITER Design Review, in 2007. Recently, the ITER management decided to provide a budget for building ELMs control coils, the design of which remains to be chosen between two of the three options that we proposed. Finally, in order to understand better the non-linear magnetohydrodynamics phenomena taking place in ELMs control by RMPs, we performed numerical simulations, in particular with the JOREK code for a DIII-D case. The simulations reveal the existence of convection cells induced at the edge by the magnetic perturbations, and the possible screening of the RMPs in presence of rotation

  20. Nonlinear localized modes in PT-symmetric optical media with competing gain and loss

    Energy Technology Data Exchange (ETDEWEB)

    Midya, Bikashkali, E-mail: bikash.midya@gmail.com [Physics and Applied Mathematics Unit, Indian Statistical Institute, Kolkata 700108 (India); Roychoudhury, Rajkumar, E-mail: rroychoudhury123@gmail.com [Advanced Center for Nonlinear and Complex Phenomena, Kolkata 700075 (India)

    2014-02-15

    The existence and stability of the nonlinear spatial localized modes are investigated in parity-time symmetric optical media characterized by a generic complex hyperbolic refractive index distribution with competing gain and loss profile. The exact analytical expression of the localized modes are found for all values of the competing parameter and in the presence of both the self-focusing and self-defocusing Kerr nonlinearity. The effects of competing gain/loss profile on the stability structure of these localized modes are discussed with the help of linear stability analysis followed by the direct numerical simulation of the governing equation. The spatial localized modes in two-dimensional geometry as well as the transverse power-flow density associated with these localized modes are also examined. -- Highlights: • Existence of localized modes is investigated in PT-symmetric complex potentials. • Exact analytical expression of the localized modes is obtained. • Effect of gain/loss profile on the stability of these localized modes is discussed. • Localized modes in 2D and associated transverse power-flow density are also examined.

  1. Multifractality in edge localized modes in Japan Atomic Energy Research Institute Tokamak-60 Upgrade

    International Nuclear Information System (INIS)

    Bak, P.E.; Asakura, N.; Miura, Y.; Nakano, T.; Yoshino, R.

    2001-01-01

    The temporal losses of confinement during edge localized modes in the Japan Atomic Energy Research Institute Tokamak-60 Upgrade (JT-60U) show multifractal scaling and the spectra are generally smooth, but in some cases there are signs of discontinuous derivatives. Dynamics of the Sugama-Horton model, interpreted as edge localized modes, also display multifractal scaling. The spectra display singularities in the derivative, which can be interpreted as a phase transition. It is argued that the multifractal spectra of edge localized modes can be used to discriminate between different experimental discharges and validate edge localized mode models

  2. Investigation of ELM [edge localized mode] Dynamics with the Resonant Magnetic Perturbation Effects

    Energy Technology Data Exchange (ETDEWEB)

    Pankin, Alexei Y.; Kritz, Arnold H.

    2011-07-19

    Topics covered are: anomalous transport and E x B flow shear effects in the H-mode pedestal; RMP (resonant magnetic perturbation) effects in NSTX discharges; development of a scaling of H-mode pedestal in tokamak plasmas with type I ELMs (edge localized modes); and divertor heat load studies.

  3. Features of the repetition frequency of edge localized modes in EAST

    DEFF Research Database (Denmark)

    Jiang, M.; Xiao, C.; Xu, G.S.

    2012-01-01

    This paper presents the features of the edge localized modes (ELMs) observed in the 2010 experimental campaign on the Experimental Advanced Superconducting Tokamak (EAST). The first high-confinement mode (H-mode) at an H-factor of HIPB98(y, 2)~1 has been obtained with about 1 MW lower hybrid wave...

  4. Extended and localized vibrational modes in (1-3) Penrose-like piezocomposites

    Science.gov (United States)

    Montero de Espinosa, F.; Torres, M.

    1994-09-01

    Acoustic vibrational modes of piezocomposites with ceramic bars arranged at the vertices of both perfect Penrose tilings and random Penrose tilings have directly been observed by recording the corresponding standing vibration amplitude pattern. The random Penrose tiling exhibits similar although smoother spectrum than the perfect Penrose one. For both structures, the existence of extended and localized modes is shown. Resonances frequencies at the edges of the spectrum pseudogap correspond to localized and highly entropic modes. As expected, the modes are more localized in the random Penrose tiling case.

  5. Intrinsic spatial resolution limitations due to differences between positron emission position and annihilation detection localization

    International Nuclear Information System (INIS)

    Perez, Pedro; Malano, Francisco; Valente, Mauro

    2012-01-01

    Since its successful implementation for clinical diagnostic, positron emission tomography (PET) represents the most promising medical imaging technique. The recent major growth of PET imaging is mainly due to its ability to trace the biologic pathways of different compounds in the patient's body, assuming the patient can be labeled with some PET isotope. Regardless of the type of isotope, the PET imaging method is based on the detection of two 511-keV gamma photons being emitted in opposite directions, with almost 180 deg between them, as a consequence of electron-positron annihilation. Therefore, this imaging method is intrinsically limited by random uncertainties in spatial resolutions, related with differences between the actual position of positron emission and the location of the detected annihilation. This study presents an approach with the Monte Carlo method to analyze the influence of this effect on different isotopes of potential implementation in PET. (author)

  6. Tuneabilities of localized electromagnetic modes in random nanostructures for random lasing

    Science.gov (United States)

    Takeda, S.; Obara, M.

    2010-02-01

    The modal characteristics of localized electromagnetic waves inside random nanostructures are theoretically presented. It is crucial to know the tuneabilities of the localized modes systematically for demonstrating a specific random lasing application. By use of FDTD (Finite-Difference Time-Domain) method, we investigated the impulse response of two-dimensional random nanostructures consisting of closely packed cylindrical dielectric columns, and precisely analyzed the localized modes. We revealed the tuneability of the frequency of the localized modes by controlling the medium configurations: diameter, spatial density, and refractive index of the cylinders. Furthermore, it is found to be able to tune the Q (quality) factors of the localized modes dramatically by controlling simply the system size of the entire medium. The observed Q factors of approximately 1.6×104 were exhibited in our random disordered structures.

  7. Multi-Fault Diagnosis of Rolling Bearings via Adaptive Projection Intrinsically Transformed Multivariate Empirical Mode Decomposition and High Order Singular Value Decomposition.

    Science.gov (United States)

    Yuan, Rui; Lv, Yong; Song, Gangbing

    2018-04-16

    Rolling bearings are important components in rotary machinery systems. In the field of multi-fault diagnosis of rolling bearings, the vibration signal collected from single channels tends to miss some fault characteristic information. Using multiple sensors to collect signals at different locations on the machine to obtain multivariate signal can remedy this problem. The adverse effect of a power imbalance between the various channels is inevitable, and unfavorable for multivariate signal processing. As a useful, multivariate signal processing method, Adaptive-projection has intrinsically transformed multivariate empirical mode decomposition (APIT-MEMD), and exhibits better performance than MEMD by adopting adaptive projection strategy in order to alleviate power imbalances. The filter bank properties of APIT-MEMD are also adopted to enable more accurate and stable intrinsic mode functions (IMFs), and to ease mode mixing problems in multi-fault frequency extractions. By aligning IMF sets into a third order tensor, high order singular value decomposition (HOSVD) can be employed to estimate the fault number. The fault correlation factor (FCF) analysis is used to conduct correlation analysis, in order to determine effective IMFs; the characteristic frequencies of multi-faults can then be extracted. Numerical simulations and the application of multi-fault situation can demonstrate that the proposed method is promising in multi-fault diagnoses of multivariate rolling bearing signal.

  8. Excitations and management of the nonlinear localized gap modes

    Indian Academy of Sciences (India)

    2015-09-23

    Sep 23, 2015 ... Home; Journals; Pramana – Journal of Physics; Volume 85; Issue 5 ... We discuss about the theory of nonlinear localized excitations, such as soliton and compactons in the gap of the linear spectrum of the nonlinear systems. ... Department of Physics, Savitribai Phule Pune University, Pune 411 007, India ...

  9. Excitations and management of the nonlinear localized gap modes

    Indian Academy of Sciences (India)

    2015-09-23

    Sep 23, 2015 ... We discuss about the theory of nonlinear localized excitations, such as soliton and compactons in the gap of the linear spectrum of the nonlinear systems. We show how the gap originates in the linear spectrum using examples of a few systems, such as nonlinear lattices, Bose–Einstein condensates in ...

  10. Parametric localized modes in quadratic nonlinear photonic structures

    DEFF Research Database (Denmark)

    Sukhorukov, Andrey A.; Kivshar, Yuri S.; Bang, Ole

    2001-01-01

    interfaces, we derive an effective discrete model for the amplitudes of the fundamental and second-harmonic waves at the interfaces (the so-called discrete chi2 equations) and find, numerically and analytically, the spatially localized solutions-discrete gap solitons. For a single nonlinear interface...

  11. Changes in intrinsic local connectivity after reading intervention in children with autism.

    Science.gov (United States)

    Maximo, Jose O; Murdaugh, Donna L; O'Kelley, Sarah; Kana, Rajesh K

    2017-12-01

    Most of the existing behavioral and cognitive intervention programs in autism spectrum disorders (ASD) have not been tested at the neurobiological level, thus falling short of finding quantifiable neurobiological changes underlying behavioral improvement. The current study takes a translational neuroimaging approach to test the impact of a structured visual imagery-based reading intervention on improving reading comprehension and assessing its underlying local neural circuitry. Behavioral and resting state functional MRI (rs-fMRI) data were collected from children with ASD who were randomly assigned to an Experimental group (ASD-EXP; n=14) and a Wait-list control group (ASD-WLC; n=14). Participants went through an established reading intervention training program (Visualizing and Verbalizing for language comprehension and thinking or V/V; 4-h per day, 10-weeks, 200h of face-to-face instruction). Local functional connectivity was examined using a connection density approach from graph theory focusing on brain areas considered part of the Reading Network. The main results are as follows: (I) the ASD-EXP group showed significant improvement, compared to the ASD-WLC group, in their reading comprehension ability evidenced from change in comprehension scores; (II) the ASD-EXP group showed increased local brain connectivity in Reading Network regions compared to the ASD-WLC group post-intervention; (III) intervention-related changes in local brain connectivity were observed in the ASD-EXP from pre to post-intervention; and (IV) improvement in language comprehension significantly predicted changes in local connectivity. The findings of this study provide novel insights into brain plasticity in children with developmental disorders using targeted intervention programs. Published by Elsevier Inc.

  12. Structural Damage Localization by Outlier Analysis of Signal-processed Mode Shapes

    DEFF Research Database (Denmark)

    Ulriksen, Martin Dalgaard; Damkilde, Lars

    2016-01-01

    Contrary to global modal parameters such as eigenfrequencies, mode shapes inherently provide structural information on a local level. Therefore, this particular modal parameter and its derivatives are utilized extensively for damage identification. Typically, more or less advanced mathematical...

  13. Damage localization by statistical evaluation of signal-processed mode shapes

    DEFF Research Database (Denmark)

    Ulriksen, Martin Dalgaard; Damkilde, Lars

    2015-01-01

    Due to their inherent ability to provide structural information on a local level, mode shapes and their derivatives are utilized extensively for structural damage identification. Typically, more or less advanced mathematical methods are implemented to identify damage-induced discontinuities...

  14. MISR Level 1B1 Local Mode Radiance Data V002

    Data.gov (United States)

    National Aeronautics and Space Administration — The MISR Local Mode Level 1B1 Product contains the data numbers (DNs) radiometrically scaled to radiances with no geometric resampling.The MISR Level 1B1 Radiance...

  15. Localized bulk electron heating with ICRF mode conversion in the JET tokamak

    DEFF Research Database (Denmark)

    Mantsinen, M.J.; Mayoral, M.-L.; Eester, D. Van

    2004-01-01

    Ion cyclotron resonance frequencies (ICRF) mode conversion has been developed for localized on-axis and off-axis bulk electron heating on the JET tokamak. The fast magnetosonic waves launched from the low-field side ICRF antennas are mode-converted to short-wavelength waves on the high-field side...

  16. Local pulsatile contractions are an intrinsic property of the myosin 2A motor in the cortical cytoskeleton of adherent cells

    Science.gov (United States)

    Baird, Michelle A.; Billington, Neil; Wang, Aibing; Adelstein, Robert S.; Sellers, James R.; Fischer, Robert S.; Waterman, Clare M.

    2017-01-01

    The role of nonmuscle myosin 2 (NM2) pulsatile dynamics in generating contractile forces required for developmental morphogenesis has been characterized, but whether these pulsatile contractions are an intrinsic property of all actomyosin networks is not known. Here we used live-cell fluorescence imaging to show that transient, local assembly of NM2A “pulses” occurs in the cortical cytoskeleton of single adherent cells of mesenchymal, epithelial, and sarcoma origin, independent of developmental signaling cues and cell–cell or cell–ECM interactions. We show that pulses in the cortical cytoskeleton require Rho-associated kinase– or myosin light chain kinase (MLCK) activity, increases in cytosolic calcium, and NM2 ATPase activity. Surprisingly, we find that cortical cytoskeleton pulses specifically require the head domain of NM2A, as they do not occur with either NM2B or a 2B-head-2A-tail chimera. Our results thus suggest that pulsatile contractions in the cortical cytoskeleton are an intrinsic property of the NM2A motor that may mediate its role in homeostatic maintenance of tension in the cortical cytoskeleton of adherent cells. PMID:27881665

  17. Local pulsatile contractions are an intrinsic property of the myosin 2A motor in the cortical cytoskeleton of adherent cells.

    Science.gov (United States)

    Baird, Michelle A; Billington, Neil; Wang, Aibing; Adelstein, Robert S; Sellers, James R; Fischer, Robert S; Waterman, Clare M

    2017-01-15

    The role of nonmuscle myosin 2 (NM2) pulsatile dynamics in generating contractile forces required for developmental morphogenesis has been characterized, but whether these pulsatile contractions are an intrinsic property of all actomyosin networks is not known. Here we used live-cell fluorescence imaging to show that transient, local assembly of NM2A "pulses" occurs in the cortical cytoskeleton of single adherent cells of mesenchymal, epithelial, and sarcoma origin, independent of developmental signaling cues and cell-cell or cell-ECM interactions. We show that pulses in the cortical cytoskeleton require Rho-associated kinase- or myosin light chain kinase (MLCK) activity, increases in cytosolic calcium, and NM2 ATPase activity. Surprisingly, we find that cortical cytoskeleton pulses specifically require the head domain of NM2A, as they do not occur with either NM2B or a 2B-head-2A-tail chimera. Our results thus suggest that pulsatile contractions in the cortical cytoskeleton are an intrinsic property of the NM2A motor that may mediate its role in homeostatic maintenance of tension in the cortical cytoskeleton of adherent cells. © 2017 Baird et al. This article is distributed by The American Society for Cell Biology under license from the author(s). Two months after publication it is available to the public under an Attribution–Noncommercial–Share Alike 3.0 Unported Creative Commons License (http://creativecommons.org/licenses/by-nc-sa/3.0).

  18. Indo-Pacific variability on seasonal to multidecadal timescales. Part I: Intrinsic SST modes in models and observations

    OpenAIRE

    Slawinska, Joanna; Giannakis, Dimitrios

    2016-01-01

    The variability of Indo-Pacific SST on seasonal to multidecadal timescales is investigated using a recently introduced technique called nonlinear Laplacian spectral analysis (NLSA). Through this technique, drawbacks associated with ad hoc pre-filtering of the input data are avoided, enabling recovery of low-frequency and intermittent modes not previously accessible via classical approaches. Here, a multiscale hierarchy of spatiotemporal modes is identified for Indo-Pacific SST in millennial c...

  19. Experiment study of edge localized mode with plasma vertical jogging in HL-2A tokamak

    Science.gov (United States)

    Wu, N.; Chen, S. Y.; Song, X. M.; Mou, M. L.; Huang, J.; Wang, Z. T.; Tang, C. J.; Song, X.; Xia, F.; Jiang, M.; HL-2A Team

    2017-09-01

    The effect of plasma vertical jogging on edge localized modes (ELMs) is investigated in HL-2A tokamak. During the experiment, plasma jogging with a period of about 75 ms is performed, and the results show that both the ELM amplitude and period decrease when the plasma moves upward, which are qualitatively explained by the simulation based on the theory of peeling-ballooning mode including the resistivity effect. The upward movement of plasma causes a change in pedestal parameters, and then the dominant toroidal mode shifts to a relatively high-n mode with the effects of resistivity and diamagnetic, which lead to smaller ELM amplitudes.

  20. Stationary localized modes of the quintic nonlinear Schroedinger equation with a periodic potential

    International Nuclear Information System (INIS)

    Alfimov, G. L.; Konotop, V. V.; Pacciani, P.

    2007-01-01

    We consider localized modes (bright solitons) of the one-dimensional quintic nonlinear Schroedinger equation with a periodic potential, describing several mean-field models of low-dimensional condensed gases. In the case of attractive nonlinearity we deduce sufficient conditions for collapse. We show that there exist spatially localized modes with arbitrarily large numbers of particles. We study such solutions in the semi-infinite gap (attractive case) and in the first gap (attractive and repulsive cases), and show that a nonzero minimum value of the number of particles is necessary for a localized mode to be created. In the limit of large negative frequencies (attractive case) we observe quantization of the number of particles of the stationary modes. Such solutions can be interpreted as coupled Townes solitons and appear to be stable. The modes in the first gap have numbers of particles infinitely growing with frequencies approaching one of the gap edges, which is explained by the power decay of the modes. Stability of the localized modes is discussed

  1. Localized stability criterion for kink modes in systems with small shear

    International Nuclear Information System (INIS)

    Hastie, R.J.; Johnson, J.L.

    1986-02-01

    A localized magnetohydrodynamic stability criterion for ideal kink instabilities is determined for systems where the safety factor has a local minimum on a rational surface with no pressure gradient. These modes are stable in the cylindrical limit, but toroidal effects can make them unstable. They could provide a partial explanation for the rapid current penetration observed in tokamaks. 7 refs

  2. Reduction of Edge-Localized Mode Intensity Using High-Repetition-Rate Pellet Injection in Tokamak H-Mode Plasmas

    Science.gov (United States)

    Baylor, L. R.; Commaux, N.; Jernigan, T. C.; Brooks, N. H.; Combs, S. K.; Evans, T. E.; Fenstermacher, M. E.; Isler, R. C.; Lasnier, C. J.; Meitner, S. J.; Moyer, R. A.; Osborne, T. H.; Parks, P. B.; Snyder, P. B.; Strait, E. J.; Unterberg, E. A.; Loarte, A.

    2013-06-01

    High repetition rate injection of deuterium pellets from the low-field side (LFS) of the DIII-D tokamak is shown to trigger high-frequency edge-localized modes (ELMs) at up to 12× the low natural ELM frequency in H-mode deuterium plasmas designed to match the ITER baseline configuration in shape, normalized beta, and input power just above the H-mode threshold. The pellet size, velocity, and injection location were chosen to limit penetration to the outer 10% of the plasma. The resulting perturbations to the plasma density and energy confinement time are thus minimal (pellet injection excites a localized high-n instability. Triggered ELMs produce up to 12× lower energy and particle fluxes to the divertor, and result in a strong decrease in plasma core impurity density. These results show for the first time that shallow, LFS pellet injection can dramatically accelerate the ELM cycle and reduce ELM energy fluxes on plasma facing components, and is a viable technique for real-time control of ELMs in ITER.

  3. Trapped modes in an infinite or semi-infinite tube with a local enlargement.

    Science.gov (United States)

    Li, Wei-Sha; Zou, Jiaqi; Lee, Kang Yong; Li, Xian-Fang

    2016-09-01

    Trapped modes in a hard cylindrical tube with a local axisymmetric enlargement or bulge and filled with a uniform acoustic medium is studied. The governing Helmholtz equation in the cylindrical coordinate system is employed to deal with this problem through the domain decomposition method and matching technique. The trapped modes and the corresponding frequencies less than the threshold frequency or cut-off frequency are derived. It is found that in addition to the fundamental mode, the second- and higher-order trapped modes exist and depend on the geometry parameters of the local bulge. The effects of the bulge radius and width on the frequencies are discussed. The local bulge leads to a decrease of the frequencies and the corresponding vibration mode is localized near the bulge. A multimodal analysis is made and frequency band gap of generalized trapped modes is also studied. A frequency band gap depends on the radius of a bulge and is independent of its width. The obtained results can be extended to analyze bound states in quantum wires. Copyright © 2016 Elsevier B.V. All rights reserved.

  4. Slow EEG Pattern Predicts Reduced Intrinsic Functional Connectivity in the Default Mode Network: An Inter-Subject Analysis

    Czech Academy of Sciences Publication Activity Database

    Hlinka, Jaroslav; Alexakis, C.; Diukova, A.; Liddle, P.F.; Auer, D.P.

    2010-01-01

    Roč. 53, č. 1 (2010), s. 239-246 ISSN 1053-8119 Grant - others:European Commision Fp6(XE) MEST-CT-2005-021170 Institutional research plan: CEZ:AV0Z10300504 Keywords : fMRI * electroencephalography (EEG) * BOLD * resting state * low-frequency fluctuations * functional connectivity * default mode Subject RIV: FH - Neurology Impact factor: 5.932, year: 2010

  5. Effects of locally resonant modes on underwater sound absorption in viscoelastic materials.

    Science.gov (United States)

    Wen, Jihong; Zhao, Honggang; Lv, Linmei; Yuan, Bo; Wang, Gang; Wen, Xisen

    2011-09-01

    Recently, by introducing locally resonant scatterers with spherical shape proposed in phononic crystals into design of underwater sound absorption materials, the low-frequency underwater sound absorption phenomenon induced by the localized resonances is observed. To reveal this absorption mechanism, the effect of the locally resonant mode on underwater sound absorption should be studied. In this paper, the finite element method, which is testified efficiently by comparing the calculation results with those of the layer multiple scattering method, is introduced to investigate the dynamic modes and the corresponding sound absorption of localized resonance. The relationship between the resonance modes described with the displacement contours of one unit cell and the corresponding absorption spectra is discussed in detail, which shows that the localized resonance leads to the absorption peak, and the mode conversion from longitudinal to transverse waves at the second absorption peak is more efficient than that at the first one. Finally, to show the modeling capability of FEM and investigate shape effects of locally resonant scatterers on underwater sound absorption, the absorption properties of viscoelastic materials containing locally resonant scatterers with ellipsoidal shape are discussed. © 2011 Acoustical Society of America

  6. Analytic study on localized wave modes driven by relativistic ion cyclotron in nonuniform magnetic field

    Science.gov (United States)

    Tsai, Tsung-Hua; Chen, Kuan-Ren; Chen, Liu

    2008-11-01

    A systematic perturbation theory is developed to study in-depth the localized ion cyclotron modes observed in our simulation. The parabolic magnetic field profile studied in the theory is an approximation of the magnetic field at the minimum of the sinusoidal profile considered in the simulation. The theory is based on an absolute instability condition and the assumption of local homogeneity. It reveals the mechanism for driving the localized modes by fusion-produced alpha particles. The analytical results indicate that the localized modes are corresponding to the eigenmodes excited by the relativistic alpha-driven ion cyclotron instabilities at a specific eigen-frequency. The frequency, growth rate and spatial profile of the wave modes obtained from the analytical theory are in a good agreement with the simulation results. Moreover, both our analytical and simulation results show that the wave modes can exist at where the wave eigen-frequency is lower than the local harmonic cyclotron frequency; even this violates the resonance condition required for the relativistic cyclotron instabilities as generally believed.

  7. Characteristics of edge-localized modes in the experimental advanced superconducting tokamak (EAST)

    DEFF Research Database (Denmark)

    Jiang, M.; Xu, G.S.; Xiao, C.

    2012-01-01

    Edge-localized modes (ELMs) are the focus of tokamak edge physics studies because the large heat loads associated with ELMs have great impact on the divertor design of future reactor-grade tokamaks such as ITER. In the experimental advanced superconducting tokamak (EAST), the first ELMy high...... confinement modes (H-modes) were obtained with 1 MW lower hybrid wave power in conjunction with wall conditioning by lithium (Li) evaporation and real-time Li powder injection. The ELMs in EAST at this heating power are mostly type-III ELMs. They were observed close to the H-mode threshold power and produced...... with an energy loss of up to 5% of the stored energy. Statistically, the ELM frequencies are several hundred hertz and the frequency appears to decrease with q(95), the safety factor at 95% of the flux surface. When an ion cyclotron resonance frequency wave was injected during the H-mode phases, the ELM...

  8. Failure mode and fracture behavior evaluation of pipes with local wall thinning subjected to bending load

    International Nuclear Information System (INIS)

    Ahn, Seok Hwan; Nam, Ki Woo; Kim, Seon Jin; Kim, Jin Hwan; Kim, Hyun Soo; Do, Jae Yoon

    2003-01-01

    Fracture behaviors of pipes with local wall thinning are very important for the integrity of nuclear power plant. In pipes of energy plants, sometimes, the local wall thinning may result from severe Erosion-Corrosion (E/C) damage. However, the effects of local wall thinning on strength and fracture behaviors of piping system were not well studied. In this paper, the monotonic bending tests were performed of full-scale carbon steel pipes with local wall thinning. A monotonic bending load was applied to straight pipe specimens by four-point loading at ambient temperature without internal pressure. From the tests, fracture behaviors and fracture strength of locally thinned pipe were manifested systematically. The observed failure modes were divided into four types; ovalization, crack initiation/growth after ovalization, local buckling and crack initiating/growth after local buckling. Also, the strength and the allowable limit of piping system with local wall thinning were evaluated

  9. Kelvin-Helmholtz instability as a possible cause of edge localized modes

    International Nuclear Information System (INIS)

    Strauss, H.R.

    1992-01-01

    Edge localized modes may be a Kelvin-Helmholtz instability caused by the sheared rotation of H-mode plasmas. The Kelvin-Helmholtz instability is stabilized by coupling to Alfven waves. There is a critical velocity gradient, of the order of the Alfven velocity divided by the magnetic shear length. This is verified in a numerical simulation. The critical velocity shear is consistent with experiment. A non-linear simulation shows how the Kelvin-Helmholtz mode can cause oscillations of the velocity profile. (author). Letter-to-the-editor. 13 refs, 6 figs

  10. Local modes analysis of a rotating marine ship propeller with higher order harmonic elements

    Science.gov (United States)

    Feng, Chen; Yong, Chen; Hongxing, Hua

    2016-09-01

    An annular harmonic finite element for the computation of the local modes of a pretwisted ship propeller is developed. The elements take into account both the gyroscopic effect and centrifugal stiffening of the propeller blades. The displacement field is expressed by a truncated Fourier series along the angle and by polynomial shape functions in the radial direction. As an example, the dynamic behaviour, i.e. the nature frequency and local modes, of a ship propeller is studied, and compared with ANSYS, both of which have good consistency.

  11. The evolution of local participation and the mode of knowledge production in Arctic research

    Directory of Open Access Journals (Sweden)

    Nicolas D. Brunet

    2014-06-01

    Full Text Available Arctic science is often claimed to have been transformed by the increased involvement of local people, but these claims of a new research paradigm have not been empirically evaluated. We argue that the "new" participatory research paradigm emerging in Arctic science embodies many of the principles of the Mode 2 knowledge production framework. Using the Mode 2 thesis as an assessment framework, we examined research articles appearing between 1965 and 2010 in the journal Arctic to assess the extent to which there has been a paradigm shift toward more participatory approaches. Results suggest that the involvement of local people has increased only slightly over the last half century and continues to vary systematically among disciplines, organizations, and regions. Analysis of three additional journals focused on Arctic and circumpolar science establishes the generality of these slight increases in local involvement. There is clearly room for more community involvement in Arctic science, but achieving this will require either increasing the proportional representation of the organizations, disciplines, and regions with a track record of successful Mode 2 research, or encouraging Mode 2 research innovation within the organizations, disciplines, and regions currently predominated by Mode 1 approaches.

  12. Processing of laser Doppler flowmetry signals from healthy subjects and patients with varicose veins: Information categorisation approach based on intrinsic mode functions and entropy computation.

    Science.gov (United States)

    Humeau-Heurtier, Anne; Klonizakis, Markos

    2015-06-01

    The diagnosis of pathologies from signal processing approaches has shown to be of importance. This can provide noninvasive information at the earliest stage. In this work, the problem of categorising - in a quantifiable manner - information content of microvascular blood flow signals recorded in healthy participants and patients with varicose veins is addressed. For this purpose, laser Doppler flowmetry (LDF) signals - that reflect microvascular blood flow - recorded both at rest and after acetylcholine (ACh) stimulation (an endothelial-dependent vasodilator) are analyzed. Each signal is processed with the empirical mode decomposition (EMD) to obtain its intrinsic mode functions (IMFs). An entropy measure of each IMFs is then computed. The results show that IMFs of LDF signals have different complexity for different physiologic/pathological states. This is true both at rest and after ACh stimulation. Thus, the proposed framework (EMD + entropy computation) may be used to gain a noninvasive understanding of LDF signals in patients with microvascular dysfunctions. Copyright © 2015 IPEM. Published by Elsevier Ltd. All rights reserved.

  13. Automated localization and segmentation techniques for B-mode ultrasound images: A review.

    Science.gov (United States)

    Meiburger, Kristen M; Acharya, U Rajendra; Molinari, Filippo

    2018-01-01

    B-mode ultrasound imaging is used extensively in medicine. Hence, there is a need to have efficient segmentation tools to aid in computer-aided diagnosis, image-guided interventions, and therapy. This paper presents a comprehensive review on automated localization and segmentation techniques for B-mode ultrasound images. The paper first describes the general characteristics of B-mode ultrasound images. Then insight on the localization and segmentation of tissues is provided, both in the case in which the organ/tissue localization provides the final segmentation and in the case in which a two-step segmentation process is needed, due to the desired boundaries being too fine to locate from within the entire ultrasound frame. Subsequenly, examples of some main techniques found in literature are shown, including but not limited to shape priors, superpixel and classification, local pixel statistics, active contours, edge-tracking, dynamic programming, and data mining. Ten selected applications (abdomen/kidney, breast, cardiology, thyroid, liver, vascular, musculoskeletal, obstetrics, gynecology, prostate) are then investigated in depth, and the performances of a few specific applications are compared. In conclusion, future perspectives for B-mode based segmentation, such as the integration of RF information, the employment of higher frequency probes when possible, the focus on completely automatic algorithms, and the increase in available data are discussed. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. All-solid-state cavity QED using Anderson-localized modes in disordered photonic crystal waveguides

    DEFF Research Database (Denmark)

    Lodahl, Peter; Sapienza, Luca; Nielsen, Henri Thyrrestrup

    2010-01-01

    We employ Anderson-localized modes in deliberately disordered photonic crystal waveguides to confine light and enhance the interaction with matter. A 15-fold enhancement of the decay rate of a single quantum dot is observed meaning that 94% of the emitted single photons are coupled to an Anderson...

  15. Local complementary inputs as drivers of entry mode choices : The case of US investments in Brazil

    NARCIS (Netherlands)

    Hennart, J.M.A.; Sheng, H.H.; Pimenta, G.

    The theory of entry mode choice has modeled that choice as solely determined by the foreign investor. Hennart's bundling model, on the other hand, argues that foreign entry into a host market involves the bundling of intangibles contributed by the foreign investor with local complementary inputs

  16. Impact of age, intrinsic subtype and local treatment on long-term local-regional recurrence and breast cancer mortality among low-risk breast cancer patients

    DEFF Research Database (Denmark)

    Laurberg, Tinne; Alsner, Jan; Tramm, Trine

    2017-01-01

    -, HER2 receptor and Ki67.RESULTS: The majority of the tumors had a luminal subtype: 70% Luminal-A (LumA), 16% Luminal-B (LumB), and 10% Luminal-HER2 + (Lum-HER2+). The distribution of intrinsic subtypes between younger (≤45 years) and older (>45 years) patients was similar. Intrinsic subtypes had......, no distinct mortality pattern was observed, and the 20-year breast cancer mortality was not associated with intrinsic subtypes.CONCLUSION: Among low-risk patients, 96% of the tumors were Luminal and the distribution of intrinsic subtypes between younger (≤45 years) and older (>45 years) patients was similar...

  17. Importance of intrinsic and non-network contribution in PageRank centrality and its effect on PageRank localization

    OpenAIRE

    Deyasi, Krishanu

    2016-01-01

    PageRank centrality is used by Google for ranking web-pages to present search result for a user query. Here, we have shown that PageRank value of a vertex also depends on its intrinsic, non-network contribution. If the intrinsic, non-network contributions of the vertices are proportional to their degrees or zeros, then their PageRank centralities become proportion to their degrees. Some simulations and empirical data are used to support our study. In addition, we have shown that localization ...

  18. Finite element modeling of temperature load effects on the vibration of local modes in multi-cable structures

    Science.gov (United States)

    Treyssède, Fabien

    2018-01-01

    Understanding thermal effects on the vibration of local (cable-dominant) modes in multi-cable structures is a complicated task. The main difficulty lies in the modification by temperature change of cable tensions, which are then undetermined. This paper applies a finite element procedure to investigate the effects of thermal loads on the linear dynamics of prestressed self-weighted multi-cable structures. Provided that boundary conditions are carefully handled, the discretization of cables with nonlinear curved beam elements can properly represent the thermoelastic behavior of cables as well as their linearized dynamics. A three-step procedure that aims to replace applied pretension forces with displacement continuity conditions is used. Despite an increase in the computational cost related to beam rotational degrees of freedom, such an approach has several advantages. Nonlinear beam finite elements are usually available in commercial codes. The overall method follows a thermoelastic geometrically non-linear analysis and hereby includes the main sources of non-linearities in multi-cable structures. The effects of cable bending stiffness, which can be significant, are also naturally accounted for. The accuracy of the numerical approach is assessed thanks to an analytical model for the vibration of a single inclined cable under temperature change. Then, the effects of thermal loads are investigated for two cable bridges, highlighting how natural frequencies can be affected by temperature. Although counterintuitive, a reverse relative change of natural frequency may occur for certain local modes. This phenomenon can be explained by two distinct mechanisms, one related to the physics intrinsic to cables and the other related to the thermal deflection of the superstructure. Numerical results show that cables cannot be isolated from the rest of the structure and the importance of modeling the whole structure for a quantitative analysis of temperature effects on the

  19. Intrinsic Local Constituents of Molecular Electronic Wave Functions.I. Exact Representation of the Density Matrix in Terms of Chemically Deformed and Oriented Atomic Minimal Basis Set Orbitals

    Energy Technology Data Exchange (ETDEWEB)

    Joseph Ivanic; Gregory J. Atchity; Klaus Ruedenberg

    2007-02-12

    A coherent, intrinsic, basis-set-independent analysis is developed for the invariants of the first-order density matrix of an accurate molecular electronic wavefunction. From the hierarchical ordering of the natural orbitals, the zeroth-order orbital space is deduced, which generates the zeroth-order wavefunction, typically an MCSCF function in the full valence space. It is shown that intrinsically embedded in such wavefunctions are elements that are local in bond regions and elements that are local in atomic regions. Basis-set-independent methods are given that extract and exhibit the intrinsic bond orbitals and the intrinsic minimal-basis quasi-atomic orbitals in terms of which the wavefunction can be exactly constructed. The quasi-atomic orbitals are furthermore oriented by a basis-set independent method (viz. maximization of the sum of the fourth powers of all off-diagonal density matrix elements) so as to exhibit clearly the chemical interactions. The unbiased nature of the method allows for the adaptation of the localized and directed orbitals to changing geometries.

  20. Identification of Majorana Modes in Interacting Systems by Local Integrals of Motion

    Science.gov (United States)

    Wieckowski, Andrzej; Maśka, Maciej M.; Mierzejewski, Marcin

    2018-01-01

    Recently, there has been substantial progress in methods of identifying local integrals of motion in interacting integrable models or in systems with many-body localization. We show that one of these approaches can be utilized for constructing local, conserved, Majorana fermions in systems with an arbitrary many-body interaction. As a test case, we first investigate a noninteracting Kitaev model and demonstrate that this approach perfectly reproduces the standard results. Then, we discuss how the many-body interactions influence the spatial structure and the lifetime of the Majorana modes. Finally, we determine the regime for which the information stored in the Majorana correlators is also retained for arbitrarily long times at high temperatures. We show that it is included in the regime with topologically protected soft Majorana modes, but in some cases is significantly smaller.

  1. Higher order mode spectra and the dependence of localized dipole modes on the transverse beam position in third harmonic superconducting cavities at FLASH

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Pei [Manchester Univ. (United Kingdom); Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Baboi, Nicoleta [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Jones, Roger M. [The Cockcroft Institute, Daresbury (United Kingdom)

    2012-06-15

    An electron beam entering an accelerating cavity excites a wakefield. This wakefield can be decomposed into a series of multi-poles or modes. The dominant component of the transverse wakefield is dipole. This report summarizes the higher order mode (HOM) signals of the third harmonic cavities of FLASH measured at various stages: transmission measurements in the single cavity test stand at Fermilab, at CMTB (Cryo- Module Test Bench) and at FLASH, and beam-excited measurements at FLASH. Modes in the first two dipole bands and the fifth dipole band have been identified using a global Lorentzian fit technique. The beam-pipe modes at approximately 4 GHz and some modes in the fifth dipole band have been observed as localized modes, while the first two dipole bands, containing some strong coupling cavity modes, propagate. This report also presents the dependence of the localized dipole modes on the transverse beam position. Linear dependence for various modes has been observed. This makes them suitable for beam position diagnostics. These modes, together with some propagating, strong coupling modes, have been considered in the design of a dedicated electronics for beam diagnostics with HOMs for the third harmonic cavities.

  2. On the exploitation of mode localization in surface acoustic wave MEMS

    Science.gov (United States)

    Hanley, T. H.; Gallacher, B. J.; Grigg, H. T. D.

    2017-05-01

    Mode localization sensing has been recently introduced as an alternative resonant sensing protocol. It has been shown to exhibit several advantages over other resonant methods, in particular a potential for higher sensitivity and rejection of common mode noise. This paper expounds the principles of utilising surface acoustic waves (SAW) to create a mode localization sensor. A generalised geometry consisting of a pair of coupled resonant cavities is introduced and an analytical solution found for the displacement fields within the cavities. The solution is achieved by coupling the internal cavity solutions using a ray tracing method. The results of the analytical solution are compared to a numerical solution found using commercial finite element method (FEM) software; exact agreement is found between the two solutions. The insight gained from the analytical model enables the determination of critical design parameters. A brief analysis is presented showing analogous operation to previous examples of mode localization sensors. The sensitivity of the device is shown to depend nonlinearly on the number of periods in the array coupling the two cavities.

  3. Effect of localized microstructural evolution on higher harmonic generation of guided wave modes

    Science.gov (United States)

    Choi, Gloria; Liu, Yang; Yao, Xiaochu; Lissenden, Cliff J.

    2015-03-01

    Higher harmonic generation of ultrasonic waves has the potential to be used to detect precursors to macroscale damage of phenomenon like fatigue due to microstructural evolution contributing to nonlinear material behavior. Aluminum plates having various plastic zone sizes were plastically deformed to different levels. The fundamental shear horizontal mode was then generated in the plate samples via a magnetostrictive transducer. After propagating through the plastic zone the primary wave mode (SH0) and its third harmonic (sh0) were received by a second transducer. Results of a parallel numerical study using the S1-s2 Lamb mode pair, where sensitivity to changes in third order elastic constants were investigated, are described within the context of the experimental results. Specimens used within both studies are geometrically similar and have double edge notches for dog bone samples that introduce localized plastic deformation. Through both studies, the size of the plastic zone with respect to the propagation distance and damage intensity influence the higher harmonics.

  4. Local coherence and deflation of the low quark modes in lattice QCD

    International Nuclear Information System (INIS)

    Luescher, Martin

    2007-01-01

    The spontaneous breaking of chiral symmetry in QCD is known to be linked to a non-zero density of eigenvalues of the massless Dirac operator near the origin. Numerical studies of two-flavour QCD now suggest that the low quark modes are locally coherent to a certain extent. As a consequence, the modes can be simultaneously deflated, using local projectors, with a total computational effort proportional to the lattice volume (rather than its square). Deflation has potentially many uses in lattice QCD. The technique is here worked out for the case of quark propagator calculations, where large speed-up factors and a flat scaling behaviour with respect to the quark mass are achieved

  5. Local coherence and deflation of the low quark modes in lattice QCD

    CERN Document Server

    Lüscher, Martin

    2007-01-01

    The spontaneous breaking of chiral symmetry in QCD is known to be linked to a non-zero density of eigenvalues of the massless Dirac operator near the origin. Numerical studies of two-flavour QCD now suggest that the low quark modes are locally coherent to a certain extent. As a consequence, the modes can be simultaneously deflated, using local projectors, with a total computational effort proportional to the lattice volume (rather than its square). Deflation has potentially many uses in lattice QCD. The technique is here worked out for the case of quark propagator calculations, where large speed-up factors and a flat scaling behaviour with respect to the quark mass are achieved.

  6. Ideal MHD stability and characteristics of edge localized modes on CFETR

    Science.gov (United States)

    Li, Ze-Yu; Chan, V. S.; Zhu, Yi-Ren; Jian, Xiang; Chen, Jia-Le; Cheng, Shi-Kui; Zhu, Ping; Xu, Xue-Qiao; Xia, Tian-Yang; Li, Guo-Qiang; Lao, L. L.; Snyder, P. B.; Wang, Xiao-Gang; the CFETR Physics Team

    2018-01-01

    Investigation on the equilibrium operation regime, its ideal magnetohydrodynamics (MHD) stability and edge localized modes (ELM) characteristics is performed for the China Fusion Engineering Test Reactor (CFETR). The CFETR operation regime study starts with a baseline scenario (R  =  5.7 m, B T  =  5 T) derived from multi-code integrated modeling, with key parameters {{β }N},{{β }T},{{β }p} varied to build a systematic database. These parameters, under profile and pedestal constraints, provide the foundation for the engineering design. The long wavelength low-n global ideal MHD stability of the CFETR baseline scenario, including the wall stabilization effect, is evaluated by GATO. It is found that the low-n core modes are stable with a wall at r/a  =  1.2. An investigation of intermediate wavelength ideal MHD modes (peeling ballooning modes) is also carried out by multi-code benchmarking, including GATO, ELITE, BOUT++ and NIMROD. A good agreement is achieved in predicting edge-localized instabilities. Nonlinear behavior of ELMs for the baseline scenario is simulated using BOUT++. A mix of grassy and type I ELMs is identified. When the size and magnetic field of CFETR are increased (R  =  6.6 m, B T  =  6 T), collisionality correspondingly increases and the instability is expected to shift to grassy ELMs.

  7. Local measurement of error field using naturally rotating tearing mode dynamics in EXTRAP T2R

    Science.gov (United States)

    Sweeney, R. M.; Frassinetti, L.; Brunsell, P.; Fridström, R.; Volpe, F. A.

    2016-12-01

    An error field (EF) detection technique using the amplitude modulation of a naturally rotating tearing mode (TM) is developed and validated in the EXTRAP T2R reversed field pinch. The technique was used to identify intrinsic EFs of m/n  =  1/-12, where m and n are the poloidal and toroidal mode numbers. The effect of the EF and of a resonant magnetic perturbation (RMP) on the TM, in particular on amplitude modulation, is modeled with a first-order solution of the modified Rutherford equation. In the experiment, the TM amplitude is measured as a function of the toroidal angle as the TM rotates rapidly in the presence of an unknown EF and a known, deliberately applied RMP. The RMP amplitude is fixed while the toroidal phase is varied from one discharge to the other, completing a full toroidal scan. Using three such scans with different RMP amplitudes, the EF amplitude and phase are inferred from the phases at which the TM amplitude maximizes. The estimated EF amplitude is consistent with other estimates (e.g. based on the best EF-cancelling RMP, resulting in the fastest TM rotation). A passive variant of this technique is also presented, where no RMPs are applied, and the EF phase is deduced.

  8. Understanding edge-localized mode mitigation by resonant magnetic perturbations on MAST

    Czech Academy of Sciences Publication Activity Database

    Kirk, A.; Chapman, I.T.; Liu, Y.; Cahyna, Pavel; Denner, P.; Fishpool, G.; Ham, C.J.; Harrison, J.R.; Liang, Y.; Nardon, E.; Saarelma, S.; Scannell, R.; Thornton, A.J.

    2013-01-01

    Roč. 53, č. 4 (2013), 043007-043007 ISSN 0029-5515 R&D Projects: GA ČR GAP205/11/2341 Institutional support: RVO:61389021 Keywords : EDGE LOCALIZED MODE * HOMOCLINIC TANGLE * RESONANT MAGNETIC PERTURBATION * ELM * EQUILIBRIA * EVOLUTION * STABILITY * TOKAMAKS Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.243, year: 2013 http://iopscience.iop.org/0029-5515/53/4/043007/pdf/0029-5515_53_4_043007.pdf

  9. Role of quasi-local modes in the theory of superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Gor' kov, L.P.; Eliashberg, G.M.

    1987-01-01

    An analysis of experimental data is carried out in an effort to connect superconductivity in high-Tc ceramic superconductors with low-lying quasi-local modes which interact strongly with conduction electrons. It is concluded that Eliashberg's (1960) theory of superconductivity, which takes into account the delay character of the interaction, can be used to describe the new high-temperature superconductors. 18 references.

  10. Asynchronous transfer mode and Local Area Network emulation standards, protocols, and security implications

    OpenAIRE

    Kirwin, John P.

    1999-01-01

    A complex networking technology called Asynchronous Transfer Mode (ATM) and a networking protocol called Local Area Network Emulation (LANE) are being integrated into many naval networks without any security-driven naval configuration guidelines. No single publication is available that describes security issues of data delivery and signaling relating to the transition of Ethernet to LANE and ATM. The thesis' focus is to provide: (1) an overview and security analysis of standardized protocols ...

  11. Higher order mode spectra and the dependence of localized dipole modes on the transverse beam position in third harmonic superconducting cavities at FLASH

    CERN Document Server

    Zhang, P; Jones, R M

    2012-01-01

    An electron beam entering an accelerating cavity excites a wakefield. This wakefield can be decomposed into a series of multi-poles or modes. The dominant component of the transverse wakefield is dipole. This report summarizes the higher order mode (HOM) signals of the third harmonic cavities of FLASH measured at various stages: transmission measurements in the single cavity test stand at Fermilab, at CMTB (Cryo-Module Test Bench) and at FLASH, and beam-excited measurements at FLASH. Modes in the first two dipole bands and the fifth dipole band have been identified using a global Lorentzian fit technique. The beam-pipe modes at approximately 4 GHz and some modes in the fifth dipole band have been observed as localized modes, while the first two dipole bands, containing some strong coupling cavity modes, propagate. This report also presents the dependence of the localized dipole modes on the transverse beam position. Linear dependence for various modes has been observed. This makes them suitable for beam posit...

  12. A 2:1 AV rhythm: an adverse effect of a long AV delay during DDI pacing and its prevention by the ventricular intrinsic preference algorithm in DDD mode.

    Science.gov (United States)

    Minamiguchi, Hitoshi; Oginosawa, Yasushi; Kohno, Ritsuko; Tamura, Masahito; Takeuchi, Masaaki; Otsuji, Yutaka; Abe, Haruhiko

    2012-07-01

    A 91-year-old woman received a dual-chamber pacemaker for sick sinus syndrome and intermittently abnormal atrioventricular (AV) conduction. The pacemaker was set in DDI mode with a 350-ms AV delay to preserve intrinsic ventricular activity. She complained of palpitation during AV sequential pacing. The electrocardiogram showed a 2:1 AV rhythm from 1:1 ventriculoatrial (VA) conduction during ventricular pacing in DDI mode with a long AV interval. After reprogramming of the pacemaker in DDD mode with a 250-ms AV interval and additional 100-ms prolongation of the AV interval by the ventricular intrinsic preference function, VA conduction disappeared and the patient's symptom were alleviated without increasing unnecessary right ventricular pacing. ©2011, The Authors. Journal compilation ©2011 Wiley Periodicals, Inc.

  13. Inhibition of TREK-2 K(+) channels by PI(4,5)P2: an intrinsic mode of regulation by intracellular ATP via phosphatidylinositol kinase.

    Science.gov (United States)

    Woo, Joohan; Shin, Dong Hoon; Kim, Hyun Jong; Yoo, Hae Young; Zhang, Yin-Hua; Nam, Joo Hyun; Kim, Woo Kyung; Kim, Sung Joon

    2016-08-01

    TWIK-related two-pore domain K(+) channels 1 and 2 (TREKs) are activated under various physicochemical conditions. However, the directions in which they are regulated by PI(4,5)P2 and intracellular ATP are not clearly presented yet. In this study, we investigated the effects of ATP and PI(4,5)P2 on overexpressed TREKs (HEK293T and COS-7) and endogenously expressed TREK-2 (mouse astrocytes and WEHI-231 B cells). In all of these cells, both TREK-1 and TREK-2 currents were spontaneously increased by dialysis with ATP-free pipette solution for whole-cell recording (ITREK-1,w-c and ITREK-2w-c) or by membrane excision for inside-out patch clamping without ATP (ITREK-1,i-o and ITREK-2,i-o). Steady state ITREK-2,i-o was reversibly decreased by 3 mM ATP applied to the cytoplasmic side, and this reduction was prevented by wortmannin, a PI-kinase inhibitor. An exogenous application of PI(4,5)P2 inhibited the spontaneously increased ITREKs,i-o, suggesting that intrinsic PI(4,5)P2 maintained by intracellular ATP and PI kinase may set the basal activity of TREKs in the intact cells. The inhibition of intrinsic TREK-2 by ATP was more prominent in WEHI-231 cells than astrocytes. Interestingly, unspecific screening of negative charges by poly-L-lysine also inhibited ITREK-2,i-o. Application of PI(4,5)P2 after the poly-L-lysine treatment showed dose-dependent dual effects, initial activation and subsequent inhibition of ITREK-2,i-o at low and high concentrations, respectively. In HEK293T cells coexpressing TREK-2 and a voltage-sensitive PI(4,5)P2 phosphatase, sustained depolarization increased ITREK-2,w-c initially (PI(4,5)P2 suggests the existence of dual regulatory modes that depend on PI(4,5)P2 concentration.

  14. Catastrophic degradation in high power multi-mode InGaAs-AlGaAs strained quantum well lasers with intrinsic and irradiation-induced defects

    Science.gov (United States)

    Sin, Yongkun; LaLumondiere, Stephen; DeIonno, Erica; Foran, Brendan; Presser, Nathan; Lotshaw, William; Moss, Steven C.

    2014-03-01

    A number of groups have studied reliability and degradation processes in GaAs-based lasers, but none of these studies have yielded a reliability model based on the physics of failure. Unsuccessful development of this model originates from the facts that: (i) defects related phenomena responsible for degradation in GaAs-based lasers are difficult to study due to the lack of suitable non-destructive techniques and (ii) degradation process occurs extremely fast after a long period of latency. Therefore, most of laser diode manufacturers perform accelerated multi-cell lifetests to estimate lifetimes of lasers using an empirical model, but this approach is a concern especially for satellite communication systems where high reliability is required of lasers for long-term duration in the space environment. Since it is a challenge to control defects introduced during the growth of laser structures, we studied degradation processes in broad-area InGaAs-AlGaAs strained quantum well (QW) lasers with intrinsic defects as well as those with defects introduced via proton irradiation. For the present study, we investigated the root causes of catastrophic degradation processes in MOCVD-grown broad-area InGaAs-AlGaAs strained QW lasers using various failure mode analysis techniques. A number of lasers were proton irradiated with different energies and fluences. We also studied GaAs double heterostructure (DH) test samples with different amounts of intrinsic defects introduced during MOCVD growth. These samples were proton irradiated as well to introduce additional defects. Deep level transient spectroscopy (DLTS) and time resolved photoluminescence (TR-PL) techniques were employed to study traps (due to point defects) and non-radiative recombination centers (NRCs) in pre- and poststressed lasers, respectively. These characteristics were compared with those in pre- and post-proton irradiated lasers and DHs to study the role that defects and NRCs play in catastrophic degradation

  15. Nondecaying linear and nonlinear modes in a periodic array of spatially localized dissipations

    International Nuclear Information System (INIS)

    Fernández, S C; Shchesnovich, V S

    2014-01-01

    We demonstrate the existence of extremely weakly decaying linear and nonlinear modes (i.e. modes immune to dissipation) in the one-dimensional periodic array of identical spatially localized dissipations, where the dissipation width is much smaller than the period of the array. We consider wave propagation governed by the one-dimensional Schrödinger equation in the array of identical Gaussian-shaped dissipations with three parameters, the integral dissipation strength Γ 0 , the width σ and the array period d. In the linear case, setting σ → 0, while keeping Γ 0 fixed, we get an array of zero-width dissipations given by the Dirac delta-functions, i.e. the complex Kronig–Penney model, where an infinite number of nondecaying modes appear with the Bloch index being either at the center, k = 0, or at the boundary, k = π/d, of an analogue of the Brillouin zone. By using numerical simulations we confirm that the weakly decaying modes persist for σ such that σ/d ≪ 1 and have the same Bloch index. The nondecaying modes persist also if a real-valued periodic potential is added to the spatially periodic array of dissipations, with the period of the dissipative array being a multiple of that of the periodic potential. We also consider evolution of the soliton-shaped pulses in the nonlinear Schrödinger equation with the spatially periodic dissipative lattice and find that when the pulse width is much larger than the lattice period and its wave number k is either at the center, k = 2π/d, or at the boundary, k = π/d, a significant fraction of the pulse escapes the dissipation forming a stationary nonlinear mode with the soliton-shaped envelope and the Fourier spectrum consisting of two peaks centered at k and −k. (paper)

  16. Simulated localized wear of resin luting cements for universal adhesive systems with different curing mode.

    Science.gov (United States)

    Tsujimoto, Akimasa; Barkmeier, Wayne W; Takamizawa, Toshiki; Watanabe, Hidehiko; Johnson, William W; Latta, Mark A; Miyazaki, Masashi

    2018-01-29

    This study evaluated the simulated localized wear of resin luting cements for universal adhesive systems using different curing modes. Five resin luting cements for universal adhesive systems were evaluated and subsequently subjected to wear challenge in a Leinfelder-Suzuki wear simulation device. Overall, 20 specimens from each resin luting cement were photo-cured for 40 s (dual-cure group), and 20 specimens of each material were not photo-cured (chemical-cure group). Simulated localized wear was generated using a stainless steel ball-bearing antagonist in water slurry of polymethylmethacrylate beads. In addition, scanning electron microscopy (SEM) observations of resin luting cements and wear facets were conducted. Significant differences in simulated wear and SEM observations of wear facets were evident among the materials in the dual- and chemical-cure groups. The simulated wear and SEM observations of wear facets of G-CEM LinkForce and Panavia V5 were not influenced by the curing mode. SEM observations of resin luting cements were material dependent. In most cases, dual curing appears to ensure greater wear resistance of resin luting cements than chemical curing alone. The wear resistance of some resin luting cements appears to be material dependent and is not influenced by the curing mode.

  17. The magnetic particle in a box: Analytic and micromagnetic analysis of probe-localized spin wave modes

    Science.gov (United States)

    Adur, Rohan; Du, Chunhui; Manuilov, Sergei A.; Wang, Hailong; Yang, Fengyuan; Pelekhov, Denis V.; Hammel, P. Chris

    2015-05-01

    The dipole field from a probe magnet can be used to localize a discrete spectrum of standing spin wave modes in a continuous ferromagnetic thin film without lithographic modification to the film. Obtaining the resonance field for a localized mode is not trivial due to the effect of the confined and inhomogeneous magnetization precession. We compare the results of micromagnetic and analytic methods to find the resonance field of localized modes in a ferromagnetic thin film, and investigate the accuracy of these methods by comparing with a numerical minimization technique that assumes Bessel function modes with pinned boundary conditions. We find that the micromagnetic technique, while computationally more intensive, reveals that the true magnetization profiles of localized modes are similar to Bessel functions with gradually decaying dynamic magnetization at the mode edges. We also find that an analytic solution, which is simple to implement and computationally much faster than other methods, accurately describes the resonance field of localized modes when exchange fields are negligible, and demonstrating the accessibility of localized mode analysis.

  18. Electrical addressing and temporal tweezing of localized pulses in passively mode-locked semiconductor lasers

    Science.gov (United States)

    Javaloyes, J.; Camelin, P.; Marconi, M.; Giudici, M.

    2017-08-01

    This work presents an overview of a combined experimental and theoretical analysis on the manipulation of temporal localized structures (LSs) found in passively Vertical-Cavity Surface-Emitting Lasers coupled to resonant saturable absorber mirrors. We show that the pumping current is a convenient parameter for manipulating the temporal Localized Structures, also called localized pulses. While short electrical pulses can be used for writing and erasing individual LSs, we demonstrate that a current modulation introduces a temporally evolving parameter landscape allowing to control the position and the dynamics of LSs. We show that the localized pulses drifting speed in this landscape depends almost exclusively on the local parameter value instead of depending on the landscape gradient, as shown in quasi-instantaneous media. This experimental observation is theoretically explained by the causal response time of the semiconductor carriers that occurs on an finite timescale and breaks the parity invariance along the cavity, thus leading to a new paradigm for temporal tweezing of localized pulses. Different modulation waveforms are applied for describing exhaustively this paradigm. Starting from a generic model of passive mode-locking based upon delay differential equations, we deduce the effective equations of motion for these LSs in a time-dependent current landscape.

  19. Magnetic signature of current carrying edge localized modes filaments on the Joint European Torus tokamak

    DEFF Research Database (Denmark)

    Migliucci, P.; Naulin, Volker

    2010-01-01

    Fast magnetic pickup coils are used in forward modeling to match parameters in a simple edge localized mode (ELM) filament model. This novel method allows us to determine key parameters for the evolution of the ELM filaments, as effective mode number, radial and toroidal velocities, and average...... current from standard magnetic diagnostics. The method is employed on a number of Joint European Torus (JET) [ F. Romanelli, R. Kamendje, and JET-EFDA Contributors, Nucl. Fusion 49, 104006 (2009) ] pulses. The parameter values obtained are compared to ELM filament characterization from JET and other...... tokamaks, obtained by a range of different diagnostics. It is found that the forward modeling produces key parameters such as the number of filaments and their toroidal velocity in agreement with other observations and in addition allows an estimate of the filament current....

  20. Casing Vibration Fault Diagnosis Based on Variational Mode Decomposition, Local Linear Embedding, and Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Yizhou Yang

    2017-01-01

    Full Text Available To diagnose mechanical faults of rotor-bearing-casing system by analyzing its casing vibration signal, this paper proposes a training procedure of a fault classifier based on variational mode decomposition (VMD, local linear embedding (LLE, and support vector machine (SVM. VMD is used first to decompose the casing signal into several modes, which are subsignals usually modulated by fault frequencies. Vibrational features are extracted from both VMD subsignals and the original one. LLE is employed here to reduce the dimensionality of these extracted features and make the samples more separable. Then low-dimensional data sets are used to train the multiclass SVM whose accuracy is tested by classifying the test samples. When the parameters of LLE and SVM are well optimized, this proposed method performs well on experimental data, showing its capacity of diagnosing casing vibration faults.

  1. SUPPESSION OF LARGE EDGE LOCALIZED MODES IN HIGH CONFINEMENT DIII-D PLASMAS WITH A STOCHASTIC MAGNETIC BOUNDARY

    International Nuclear Information System (INIS)

    EVANS, TE; MOYER, RA; THOMAS, PR; WATKINS, JG; OSBORNE, TH; BOEDO, JA; FENSTERMACHER, ME; FINKEN, KH; GROEBNER, RJ; GROTH, M; HARRIS, JH; LAHAYE, RJ; LASNIER, CJ; MASUZAKI, S; OHYABU, N; PRETTY, D; RHODES, TL; REIMERDES, H; RUDAKOV, DL; SCHAFFER, MJ; WANG, G; ZENG, L.

    2003-01-01

    OAK-B135 A stochastic magnetic boundary, produced by an externally applied edge resonant magnetic perturbation, is used to suppress large edge localized modes (ELMs) in high confinement (H-mode) plasmas. The resulting H-mode displays rapid, small oscillations with a bursty character modulated by a coherent 130 Hz envelope. The H-mode transport barrier is unaffected by the stochastic boundary. The core confinement of these discharges is unaffected, despite a three-fold drop in the toroidal rotation in the plasma core. These results demonstrate that stochastic boundaries are compatible with H-modes and may be attractive for ELM control in next-step burning fusion tokamaks

  2. Ion target impact energy during Type I edge localized modes in JET ITER-like Wall

    Czech Academy of Sciences Publication Activity Database

    Guillemaut, C.; Jardin, A.; Horáček, Jan; Autrique, A.; Arnoux, G.; Boom, J.; Brezinsek, S.; Coenen, J.W.; De La Luna, E.; Devaux, S.; Eich, T.; Giroud, C.; Harting, D.; Kirschner, A.; Lipschutz, B.; Matthews, G.F.; Moulton, D.; O’Mullane, M.; Stamp, M.

    2015-01-01

    Roč. 57, č. 8 (2015), č. článku 085006. ISSN 0741-3335 R&D Projects: GA MŠk LG14002 EU Projects: European Commission(XE) 633053 Institutional support: RVO:61389021 Keywords : magnetic confinement fusion * edge localized modes * JET ITER-like wall * plasma * tokamak Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 2.404, year: 2015 http://dx.doi.org/10.1088/0741-3335/57/8/085006

  3. Ultrasensitive mode-localized mass sensor with electrically tunable parametric sensitivity

    International Nuclear Information System (INIS)

    Thiruvenkatanathan, P.; Yan, J.; Seshia, A. A.; Woodhouse, J.; Aziz, A.

    2010-01-01

    We use the phenomena of mode localization and vibration confinement in pairs of weakly coupled, nearly identical microelectromechanical (MEMS) resonators as an ultrasensitive technique of detecting added mass on the resonator. The variations in the eigenstates for induced mass additions are studied and compared with corresponding resonant frequency shifts in pairs of MEMS resonators that are coupled electrostatically. We demonstrate that the relative shifts in the eigenstates can be over three orders of magnitude greater than those in resonant frequency for the same addition of mass. We also investigate the effects of voltage controlled electrical spring tuning on the parametric sensitivity of such sensors and demonstrate sensitivities tunable by over 400%.

  4. Observation of a new toroidally localized kink mode and its role in reverse-field--pinch plasmas

    International Nuclear Information System (INIS)

    Tamano, T.; Bard, W.D.; Chu, C.; Kondoh, Y.; La Haye, R.J.; Lee, P.S.; Saito, M.; Schaffer, M.J.; Taylor, P.L.

    1987-01-01

    A new type of toroidally localized kink instability, which we named the ''slinky mode,'' was observed in a reversed-field--pinch plasma in the OHTE (Ohmic heating toroidal experiment) device. It is found that the slinky mode is the result of the phase locking of several internal kink modes due to nonlinear coupling and is an effective way to approach the Taylor relaxed state

  5. Local transport analysis of L-mode plasmas in JT-60 tokamak

    International Nuclear Information System (INIS)

    Hirayama, Toshio; Kikuchi, Mitsuru; Shirai, Hiroshi; Shimizu, Katsuhiro; Yagi, Masatoshi; Koide, Yoshihiko; Ishida, Shinichi; Azumi, Masafumi.

    1991-03-01

    Local heat transport has been studied in auxiliary heated JT-60 plasmas with emphasis on understanding the deteriorated confinement observed in L-mode plasmas. The systematic experiment and analysis have been carried out in L-mode phase of divertor (single null, lower X-point), and limiter discharges with hydrogen neutral beam heating into hydrogen plasmas, based on sets of consistent experimental data including ion temperature profiles from CXR measurements. The deterioration in the energy confinement time with increasing the auxiliary heating power, so-called the power scaling, is mainly due to the degradation in ion energy transport. The confinement improvement as the plasma current increases is followed by both improvement in ion and electron transport properties. It is found that the ion thermal diffusivity has an approval dependence on the density. High ion temperature (T i (0) ≤ 12 keV) L-mode plasmas are attained at high β p up to 3.5. The centrally peaked ion temperature is significantly due to the improvement in ion transport property, which is reduced to the level of the electron thermal diffusivities. (author)

  6. Analysis of vibrating structures with localized nonlinearities using nonlinear normal modes

    International Nuclear Information System (INIS)

    Moussi, E.H.

    2013-01-01

    This work is a collaboration between EDF R and D and the Laboratory of Mechanics and Acoustics. The objective is to develop theoretical and numerical tools to compute nonlinear normal modes (NNMs) of structures with localized nonlinearities. We use an approach combining the harmonic balance and the asymptotic numerical methods, known for its robustness principally for smooth systems. Regularization techniques are used to apply this approach for the study of non-smooth problems. Moreover, several aspects of the method are improved to allow the computation of NNMs for systems with a high number of degrees of freedom (DOF). Finally, the method is implemented in Code-Aster, an open-source finite element solver developed by EDF R and D. The nonlinear normal modes of a two degrees-of-freedom system are studied and some original characteristics are observed. These observations are then used to develop a methodology for the study of systems with a high number of DOFs. The developed method is finally used to compute the NNMs for a model U-tube of a nuclear plant steam generator. The analysis of the NNMs reveals the presence of an interaction between an out-of-plane (low frequency) and an in-plane (high frequency) modes, a result also confirmed by the experiment. This modal interaction is not possible using linear modal analysis and confirms the interest of NNMs as a diagnostic tool in structural dynamics. (author) [fr

  7. Two-Dimensional Visualization of Growth and Burst of the Edge-Localized Filaments in KSTAR H-Mode Plasmas

    NARCIS (Netherlands)

    Yun, G. S.; Lee, W.; Choi, M. J.; Lee, J.; Park, H. K.; Tobias, B.; Domier, C.W.; N C Luhmann Jr.,; Donne, A. J. H.; Lee, J. H.

    2011-01-01

    The filamentary nature and dynamics of edge-localized modes (ELMs) in the KSTAR high-confinement mode plasmas have been visualized in 2D via electron cyclotron emission imaging. The ELM filaments rotating with a net poloidal velocity are observed to evolve in three distinctive stages: initial linear

  8. Excitation of terahertz modes localized on a layered superconductor: Anomalous dispersion and resonant transmission

    Science.gov (United States)

    Apostolov, S. S.; Makarov, N. M.; Yampol'skii, V. A.

    2018-01-01

    We study theoretically the optic transmission through a slab of layered superconductor separated from two dielectric leads by spatial gaps. Based on the transfer matrix formalism along with the Josephson plasma electrodynamic approach, we derive analytic expressions for the transmittance and identify the conditions for the perfect transmission. The special interest of the study is focused on the resonant transmission, which occurs when the wave does not propagate in the spatial gaps. Far from the resonance, the transmittance is exponentially small due to the total internal reflection from the lead-gap interface. However, the excitation of electromagnetic modes localized on the layered superconductor gives rise to a remarkable resonant enhancement of the transmission. Moreover, this phenomenon is significantly modified for the layered superconductors in comparison with usual dielectrics or conductors. The dispersion curves for the modes localized on the layered superconductor are proved to be nonmonotonic, thus resulting in the specific dependence of the transmittance T on the incidence angle θ . In particular, we predict the onset of two resonant peaks in the T (θ ) dependence and their subsequent merge into the broadened single peak with increasing of the wave frequency. Our analytical results are demonstrated by numerical data.

  9. Mode decomposition methods for flows in high-contrast porous media. Global-local approach

    KAUST Repository

    Ghommem, Mehdi

    2013-11-01

    In this paper, we combine concepts of the generalized multiscale finite element method (GMsFEM) and mode decomposition methods to construct a robust global-local approach for model reduction of flows in high-contrast porous media. This is achieved by implementing Proper Orthogonal Decomposition (POD) and Dynamic Mode Decomposition (DMD) techniques on a coarse grid computed using GMsFEM. The resulting reduced-order approach enables a significant reduction in the flow problem size while accurately capturing the behavior of fully-resolved solutions. We consider a variety of high-contrast coefficients and present the corresponding numerical results to illustrate the effectiveness of the proposed technique. This paper is a continuation of our work presented in Ghommem et al. (2013) [1] where we examine the applicability of POD and DMD to derive simplified and reliable representations of flows in high-contrast porous media on fully resolved models. In the current paper, we discuss how these global model reduction approaches can be combined with local techniques to speed-up the simulations. The speed-up is due to inexpensive, while sufficiently accurate, computations of global snapshots. © 2013 Elsevier Inc.

  10. Anderson localization of ballooning modes, quantum chaos and the stability of compact quasiaxially symmetric stellarators

    International Nuclear Information System (INIS)

    Redi, M.H.; Johnson, J.L.; Klasky, S.; Canik, J.; Dewar, R.L.; Cooper, W.A.

    2002-01-01

    The radially local magnetohydrodynamic (MHD) ballooning stability of a compact, quasiaxially symmetric stellarator (QAS), is examined just above the ballooning beta limit with a method that can lead to estimates of global stability. Here MHD stability is analyzed through the calculation and examination of the ballooning mode eigenvalue isosurfaces in the 3-space (s,α,θ k ); s is the edge normalized toroidal flux, α is the field line variable, and θ k is the perpendicular wave vector or ballooning parameter. Broken symmetry, i.e., deviations from axisymmetry, in the stellarator magnetic field geometry causes localization of the ballooning mode eigenfunction, and gives rise to new types of nonsymmetric eigenvalue isosurfaces in both the stable and unstable spectrum. For eigenvalues far above the marginal point, isosurfaces are topologically spherical, indicative of strong 'quantum chaos'. The complexity of QAS marginal isosurfaces suggests that finite Larmor radius stabilization estimates will be difficult and that fully three-dimensional, high-n MHD computations are required to predict the beta limit

  11. Non-negligible Contributions to Thermal Conductivity From Localized Modes in Amorphous Silicon Dioxide.

    Science.gov (United States)

    Lv, Wei; Henry, Asegun

    2016-10-21

    Thermal conductivity is important for almost all applications involving heat transfer. The theory and modeling of crystalline materials is in some sense a solved problem, where one can now calculate their thermal conductivity from first principles using expressions based on the phonon gas model (PGM). However, modeling of amorphous materials still has many open questions, because the PGM itself becomes questionable when one cannot rigorously define the phonon velocities. In this report, we used our recently developed Green-Kubo modal analysis (GKMA) method to study amorphous silicon dioxide (a-SiO 2 ). The predicted thermal conductivities exhibit excellent agreement with experiments and anharmonic effects are included in the thermal conductivity calculation for all the modes in a-SiO 2 for the first time. Previously, localized modes (locons) have been thought to have a negligible contribution to thermal conductivity, due to their highly localized nature. However, in a-SiO 2 our results indicate that locons contribute more than 10% to the total thermal conductivity from 400 K to 800 K and they are largely responsible for the increase in thermal conductivity of a-SiO 2 above room temperature. This is an effect that cannot be explained by previous methods and therefore offers new insight into the nature of phonon transport in amorphous/glassy materials.

  12. Intrinsic Motivation.

    Science.gov (United States)

    the activity. There has been very little research and theorizing which considers the topic of intrinsic motivation , yet there is a substantial amount...reported within the framework of intrinsic motivation , yet the paper reinterprets the work within that framework. It considers several approaches of

  13. Neutron Scattering Study of the Localized Mode in the beta-Pyrochlore Superconductors AOs2O6

    OpenAIRE

    Sasai, Kenzo; Hirota, Kazuma; Nagao, Yohei; Yonezawa, Shigeki; Hiroi, Zenji

    2007-01-01

    Inelastic neutron scattering and neutron powder diffraction experiments were carried out to investigate a localized mode, proposed from various bulk measurements, in the beta-pyrochlore AOs2O6 (A=K, Rb, Cs). The localized mode was identified in all the three compounds as well as another beta-pyrochlore CsW2O6. The anharmonicity of the mode is weak in RbOs2O6 and CsOs2O6 but substantial in KOs2O6.

  14. Experimental Evidence of Self-Localized and Propagating Spin Wave Modes in Obliquely Magnetized Current-Driven Nanocontacts

    Science.gov (United States)

    Bonetti, Stefano; Tiberkevich, Vasil; Consolo, Giancarlo; Finocchio, Giovanni; Muduli, Pranaba; Mancoff, Fred; Slavin, Andrei; Åkerman, Johan

    2010-11-01

    Through detailed experimental studies of the angular dependence of spin wave excitations in nanocontact-based spin-torque oscillators, we demonstrate that two distinct spin wave modes can be excited, with different frequency, threshold currents, and frequency tunability. Using analytical theory and micromagnetic simulations we identify one mode as an exchange-dominated propagating spin wave, and the other as a self-localized nonlinear spin wave bullet. Wavelet-based analysis of the simulations indicates that the apparent simultaneous excitation of both modes results from rapid mode hopping induced by the Oersted field.

  15. Magnetic field dependence of the lowest-frequency edge-localized spin wave mode in a magnetic nanotriangle.

    Science.gov (United States)

    Lin, C S; Lim, H S; Wang, Z K; Ng, S C; Kuok, M H; Adeyeye, A O

    2011-03-01

    An understanding of the spin dynamics of nanoscale magnetic elements is important for their applications in magnetic sensing and storage. Inhomogeneity of the demagnetizing field in a non-ellipsoidal magnetic element results in localization of spin waves near the edge of the element. However, relative little work has been carried out to investigate the effect of the applied magnetic fields on the nature of such localized modes. In this study, micromagnetic simulations are performed on an equilateral triangular nanomagnet to investigate the magnetic field dependence of the mode profiles of the lowest-frequency spin wave. Our findings reveal that the lowest-frequency mode is localized at the base edge of the equilateral triangle. The characteristics of its mode profile change with the ground state magnetization configuration of the nanotriangle, which, in turn, depends on the magnitude of the in-plane applied magnetic field.

  16. Nonlinear localized modes in dipolar Bose–Einstein condensates in two-dimensional optical lattices

    Energy Technology Data Exchange (ETDEWEB)

    Rojas-Rojas, Santiago, E-mail: srojas@cefop.cl [Center for Optics and Photonics and MSI-Nucleus on Advanced Optics, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Departamento de Física, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Naether, Uta [Instituto de Ciencia de Materiales de Aragón and Departamento de Física de la Materia Condensada, CSIC-Universidad de Zaragoza, 50009 Zaragoza (Spain); Delgado, Aldo [Center for Optics and Photonics and MSI-Nucleus on Advanced Optics, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Departamento de Física, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Vicencio, Rodrigo A. [Center for Optics and Photonics and MSI-Nucleus on Advanced Optics, Universidad de Concepción, Casilla 160-C, Concepción (Chile); Departamento de Física, Facultad de Ciencias, Universidad de Chile, Santiago (Chile)

    2016-09-16

    Highlights: • We study discrete two-dimensional breathers in dipolar Bose–Einstein Condensates. • Important differences in the properties of three fundamental modes are found. • Norm threshold for existence of 2D breathers varies with dipolar interaction. • The Effective Potential Method is implemented for stability analysis. • Uncommon mobility of 2D discrete solitons is observed. - Abstract: We analyze the existence and properties of discrete localized excitations in a Bose–Einstein condensate loaded into a periodic two-dimensional optical lattice, when a dipolar interaction between atoms is present. The dependence of the Number of Atoms (Norm) on the energy of solutions is studied, along with their stability. Two important features of the system are shown, namely, the absence of the Norm threshold required for localized solutions to exist in finite 2D systems, and the existence of regions in the parameter space where two fundamental solutions are simultaneously unstable. This feature enables mobility of localized solutions, which is an uncommon feature in 2D discrete nonlinear systems. With attractive dipolar interaction, a non-trivial behavior of the Norm dependence is obtained, which is well described by an analytical model.

  17. Numerical Modeling of Edge-Localized-Mode Filaments on Divertor Plates Based on Thermoelectric Currents

    International Nuclear Information System (INIS)

    Wingen, A.; Spatschek, K. H.; Evans, T. E.; Lasnier, C. J.

    2010-01-01

    Edge localized modes (ELMs) are qualitatively and quantitatively modeled in tokamaks using current bursts which have been observed in the scrape-off-layer (SOL) during an ELM crash. During the initial phase of an ELM, a heat pulse causes thermoelectric currents. They first flow in short connection length flux tubes which are initially established by error fields or other nonaxisymmetric magnetic perturbations. The currents change the magnetic field topology in such a way that larger areas of short connection length flux tubes emerge. Then currents predominantly flow in short SOL-like flux tubes and scale with the area of the flux tube assuming a constant current density. Quantitative predictions of flux tube patterns for a given current are in excellent agreement with measurements of the heat load and current flow at the DIII-D target plates during an ELM cycle.

  18. Studies of impact of plasma shaping on edge localized modes with a nonlinear code BOUT + +

    Science.gov (United States)

    Li, G. Q.; Xu, X. Q.; Snyder, P. B.; Turnbull, A. D.; Xia, T. Y.

    2014-10-01

    The plasma shaping has important effects on the edge localized modes (ELMs). In this work, with the 3-field BOUT + + code, we study the impact of the plasma shaping on the ELMs. Three kinds of typical plasma shapes are studied: circular (cbm), elongated (dbm) and shaped with X-point (meudas). Our calculations show that the shaped plasma and the X-point geometry have stabilizing effect on the ELMs. For linear ideal MHD calculation we benchmark BOUT + + results with ELITE and GATO codes. Then we study the role of non-ideal effects such as resistivity on the ELMs for the X-point geometry. Also the nonlinear calculations are carried out to study the impact of plasma shape on the ELM size. Work supported by China National Magnetic Confinement Fusion Science Program under Grant Nos. 2014GB106001 and 2013GB111000. Also performed for USDOE by LLNL under DE-AC52-07NA27344. LLNL-ABS-656997.

  19. An approach to the damping of local modes of oscillations resulting from large hydraulic transients

    Energy Technology Data Exchange (ETDEWEB)

    Dobrijevic, D.M.; Jankovic, M.V.

    1999-09-01

    A new method of damping of local modes of oscillations under large disturbance is presented in this paper. The digital governor controller is used. Controller operates in real time to improve the generating unit transients through the guide vane position and the runner blade position. The developed digital governor controller, whose control signals are adjusted using the on-line measurements, offers better damping effects for the generator oscillations under large disturbances than the conventional controller. Digital simulations of hydroelectric power plant equipped with low-head Kaplan turbine are performed and the comparisons between the digital governor control and the conventional governor control are presented. Simulation results show that the new controller offers better performances, than the conventional controller, when the system is subjected to large disturbances.

  20. Injected mass deposition thresholds for lithium granule instigated triggering of edge localized modes on EAST

    Science.gov (United States)

    Lunsford, R.; Sun, Z.; Maingi, R.; Hu, J. S.; Mansfield, D.; Xu, W.; Zuo, G. Z.; Diallo, A.; Osborne, T.; Tritz, K.; Canik, J.; Huang, M.; Meng, X. C.; Gong, X. Z.; Wan, B. N.; Li, J. G.; the EAST team

    2018-03-01

    The ability of an injected lithium granule to promptly trigger an edge localized mode (ELM) has been established in multiple experiments. By horizontally injecting granules ranging in diameter from 200 microns to 1 mm in diameter into the low field side of EAST H-mode discharges we have determined that granules with diameter  >600 microns are successful in triggering ELMs more than 95% of the time. It was also demonstrated that below 600 microns the triggering efficiency decreased roughly with granule size. Granules were radially injected from the outer midplane with velocities ~80 m s‑1 into EAST upper single null discharges with an ITER like tungsten monoblock divertor. These granules were individually tracked throughout their injection cycle in order to determine their efficacy at triggering an ELM. For those granules of sufficient size, ELM triggering was a prompt response to granule injection. By simulating the granule injection with an experimentally benchmarked neutral gas shielding (NGS) model, the ablatant mass deposition required to promptly trigger an ELM is calculated and the fractional mass deposition is determined.

  1. Direct observation of current in type-I edge-localized-mode filaments on the ASDEX Upgrade tokamak.

    Science.gov (United States)

    Vianello, N; Naulin, V; Schrittwieser, R; Müller, H W; Zuin, M; Ionita, C; Rasmussen, J J; Mehlmann, F; Rohde, V; Cavazzana, R; Maraschek, M

    2011-03-25

    Magnetically confined plasmas in the high confinement regime are regularly subjected to relaxation oscillations, termed edge localized modes (ELMs), leading to large transport events. Present ELM theories rely on a combined effect of edge current and the edge pressure gradients which result in intermediate mode number (n≅10-15) structures (filaments) localized in the perpendicular plane and extended along the field lines. By detailed localized measurements of the magnetic field perturbation associated to type-I ELM filaments, it is shown that these filaments carry a substantial current.

  2. Divertor-localized fluctuations in NSTX-U L-mode discharges

    Science.gov (United States)

    Scotti, Filippo; Soukhanovskii, V. A.; Zweben, S.; Myra, J.; Baver, D.; Sabbagh, S. A.

    2017-10-01

    The 3-D structure of divertor turbulence is characterized in NSTX-U by means of fast camera imaging. Edge and divertor turbulence can be important in determining the heat flux width in fusion devices. Field-aligned filaments are found on the divertor legs via imaging of C III and D- α emission in NBI-heated diverted L-mode discharges, similar to observations in Alcator C-Mod and MAST. These flute-like fluctuations of up to 10-20% in RMS/mean are radially localized around the separatrix and limited to the region below the X-point. Poloidal and parallel correlation lengths are a few cm (10-50ρi) and several meters, respectively. For the outer leg filaments, poloidal correlation lengths decrease along the leg away from the strike point and typical effective toroidal mode numbers are in the range of 10-20. Opposite toroidal rotation is observed for inner (co-current rotation) and outer leg (counter-current rotation) filaments with apparent poloidal propagation of 1 km/s. The poloidal motion of outer leg filaments is opposite to the one typically observed for NSTX upstream blobs in the scrape-off layer. The shape, dynamics and absence of correlation with upstream turbulence suggest that these fluctuations are generated and localized in the divertor region. Supported by US DOE DE-AC52-07NA27344, DE-AC02-09CH11466, DE-FG02- 02ER54678, DE-FG02-99ER54524.

  3. Effects of Density and Impurity on Edge Localized Modes in Tokamaks

    Science.gov (United States)

    Zhu, Ping

    2017-10-01

    Plasma density and impurity concentration are believed to be two of the key elements governing the edge tokamak plasma conditions. Optimal levels of plasma density and impurity concentration in the edge region have been searched for in order to achieve the desired fusion gain and divertor heat/particle load mitigation. However, how plasma density or impurity would affect the edge pedestal stability may have not been well known. Our recent MHD theory modeling and simulations using the NIMROD code have found novel effects of density and impurity on the dynamics of edge-localized modes (ELMs) in tokamaks. First, previous MHD analyses often predict merely a weak stabilizing effect of toroidal flow on ELMs in experimentally relevant regimes. We find that the stabilizing effects on the high- n ELMs from toroidal flow can be significantly enhanced with the increased edge plasma density. Here n denotes the toroidal mode number. Second, the stabilizing effects of the enhanced edge resistivity due to lithium-conditioning on the low- n ELMs in the high confinement (H-mode) discharges in NSTX have been identified. Linear stability analysis of the experimentally constrained equilibrium suggests that the change in the equilibrium plasma density and pressure profiles alone due to lithium-conditioning may not be sufficient for a complete suppression of the low- n ELMs. The enhanced resistivity due to the increased effective electric charge number Zeff after lithium-conditioning provides additional stabilization of the low- n ELMs. These new effects revealed in our theory analyses may help further understand recent ELM experiments and suggest new control schemes for ELM suppression and mitigation in future experiments. They may also pose additional constraints on the optimal levels of plasma density and impurity concentration in the edge region for H-mode tokamak operation. Supported by National Magnetic Confinement Fusion Science Program of China Grants 2014GB124002 and 2015GB

  4. Raman scattering investigations on Co and Mn doped ZnO epitaxial films: local vibration modes and defect associated ferromagnetism

    Science.gov (United States)

    Cao, Qiang; Liu, Guolei; Yan, Shishen; Mei, Liangmo

    2014-03-01

    The studies of local vibration modes (LVMs) of Co or Mn substitution in wurtzite ZnO lattice have been rather limited, and evolution of LVM bound defects as well as associated ferromagnetism are still poorly understood.In this paper, Raman scattering spectroscopy has been performed on high quality Co and Mn doped ZnO epitaxial films, which were grown on Al2O3 (0001) by oxygen-plasma assisted molecular beam epitaxy. Raman measurements revealed two local vibration modes (LVMs) at 723 and 699 cm?1 due to the substitution of Co2+ in wurtzite ZnO lattice. The LVM at 723 cm?1 is found to be an elemental sensitive vibration mode for Co substitution. The LVM at 699cm-1 can be attributed to enrichment of Co2+ bound with oxygen vacancy, the cobalt?oxygen vacancy?cobalt complexes, which associated with ferromagnetism. It reveals two competitive local vibration modes (LVMs) at 712 and 523 cm-1 due to the substitution of Mn ions in wurtzite ZnO lattice. The LVM at 712cm-1 is found to be an elemental vibration mode of Mn substitution in wurtzite ZnO lattice, while the LVM at 523cm-1 can be attributed to the local vibration mode of acceptor bound Mn substitution in wurtzite ZnO lattice. the NSF Grant NO. 11374189 and 51231007.

  5. Dynamic connectivity modulates local activity in the core regions of the default-mode network.

    Science.gov (United States)

    Tang, Wei; Liu, Hesheng; Douw, Linda; Kramer, Mark A; Eden, Uri T; Hämäläinen, Matti S; Stufflebeam, Steven M

    2017-09-05

    Segregation and integration are distinctive features of large-scale brain activity. Although neuroimaging studies have been unraveling their neural correlates, how integration takes place over segregated modules remains elusive. Central to this problem is the mechanism by which a brain region adjusts its activity according to the influence it receives from other regions. In this study, we explore how dynamic connectivity between two regions affects the neural activity within a participating region. Combining functional magnetic resonance imaging (fMRI) and magnetoencephalography (MEG) in the same group of subjects, we analyzed resting-state data from the core of the default-mode network. We observed directed influence from the posterior cingulate cortex (PCC) to the anterior cingulate cortex (ACC) in the 10-Hz range. This time-varying influence was associated with the power alteration in the ACC: strong influence corresponded with a decrease of power around 13-16 Hz and an increase of power in the lower (1-7 Hz) and higher (30-55 Hz) ends of the spectrum. We also found that the amplitude of the 30- to 55-Hz activity was coupled to the phase of the 3- to 4-Hz activity in the ACC. These results characterized the local spectral changes associated with network interactions. The specific spectral information both highlights the functional roles of PCC-ACC connectivity in the resting state and provides insights into the dynamic relationship between local activity and coupling dynamics of a network.

  6. Localized spin-wave modes in a triangular magnetic element studied by micro-focused Brillouin light scattering

    Energy Technology Data Exchange (ETDEWEB)

    Hwang, S.; Kwon, J.-H. [School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of); Grünberg, P. [Grünberg Center for Magnetic Nanomaterials, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of); Cho, B.K., E-mail: chobk@gist.ac.kr [School of Materials Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005 (Korea, Republic of)

    2017-09-01

    Highlights: • Direct evidence of localized mode in a triangular nano-magnet using μ-BLS. • Localized regions are identified by the internal field distribution. • The spatially resolved measurement was performed to obtain 2-D intensity map. • Spin modes in same positions can be distinguish comparing with simulated spectrum. • Localized modes were identified by comparing with the simulated spatial profiles. - Abstract: Localized spin-wave modes, which were thermally excited at a specific position in a triangular magnetic element, were investigated using micro-focused Brillouin light scattering in two saturated states, the buckle and Y-states, with an applied magnetic field of 0.24 T parallel and perpendicular to the basal edge, respectively. The measured frequency spectrum at a specific beam spot position, rather than an integrated spectrum, was analyzed by comparing it with the simulation data at a precisely selected position within the beam spot area. The analyzed results were used to plot a two-dimensional intensity map and simulation spatial profile to verify the validity of the analysis. From the analysis process, two localized spin-wave modes in a triangular magnetic element were successfully identified near the apex region in the buckle state and near the basal edge region in the Y-state.

  7. Tunable single photonic defect-mode in cholesteric liquid crystals with laser-induced local modifications of helix

    International Nuclear Information System (INIS)

    Yoshida, Hiroyuki; Lee, Chee Heng; Fujii, Akihiko; Ozaki, Masanori

    2006-01-01

    The authors demonstrate a tunable single photonic defect-mode in a single cholesteric liquid crystal material based on a structural defect introduced by local modification of the helix. An unpolymerized region of cholesteric liquid crystal acting as the defect was left between two polymerized regions via a two-photon excitation laser-lithography process. Upon polymerization, the cholesteric liquid crystal helix elongated and became thermally stable, and a single photonic defect mode was exhibited due to the contrast in the helix pitch at the defect. The defect mode showed tunability upon heating, and a 36 nm redshift was seen over a temperature range of 30 deg. C

  8. The Materials Mode in the Local Context of Mugla and the Role of Mother Tongue

    Science.gov (United States)

    Korkut, Perihan; Ertas, Abdullah

    2017-01-01

    Materials mode is one of the four modes of a lesson in the Self Evaluation Teacher Talk (SETT) framework. The aim of this study is to identify the interactional features during the materials mode in Mugla, Turkey. The lessons of English teachers at the state schools and the microteaching presentations of teacher trainees at Mugla Sitki Koçman…

  9. Edge localized mode control by resonant magnetic perturbations in tokamak plasmas

    International Nuclear Information System (INIS)

    Orain, Francois

    2014-01-01

    The growth of plasma instabilities called Edge Localized Modes (ELMs) in tokamaks results in the quasi-periodic relaxation of the edge pressure profile. These relaxations induce large heat fluxes which might be harmful for the divertor in ITER, thus ELM control is mandatory in ITER. One of the promising control methods planned in ITER is the application of external resonant magnetic perturbations (RMPs), already efficient for ELM mitigation/suppression in current tokamak experiments. However a better understanding of the interaction between ELMs, RMPs and plasma flows is needed to explain the experimental results and make reliable predictions for ITER. In this perspective, non-linear modeling of ELMs and RMPs is done with the reduced MHD code JOREK, in toroidal geometry including the X-point and the Scrape-Off Layer. The initial model has been further developed to describe self-consistent plasma flows - with the addition of the bi-fluid diamagnetic drifts, the neoclassical friction and a source of parallel rotation - and to simulate the RMP penetration consistently with the plasma response. As a first step, the plasma response to RMPs (without ELMs) is studied for JET, MAST and ITER realistic plasma parameters and geometry. The general behaviour of the plasma/RMP interaction is similar for the three studied cases: RMPs are generally screened by the formation of response currents, induced by the plasma rotation on the resonant surfaces. RMPs however penetrate at the very edge where an ergodic zone is formed. The amplification of the non-resonant spectrum of the magnetic perturbations is also observed in the core. The edge ergodization induces an enhanced transport at the edge, which slightly degrades the pedestal profiles. RMPs also generate the 3D-deformation of the plasma boundary with a maximum deformation near the X-point where lobe structures are formed. Then the full dynamics of a multi-ELM cycle (without RMPs) is modeled for the first time in realistic

  10. Effect of localized surface-plasmon mode on exciton transport and radiation emission in carbon nanotubes.

    Science.gov (United States)

    Roslyak, Oleksiy; Cherqui, Charles; Dunlap, David H; Piryatinski, Andrei

    2014-07-17

    We report on a general theoretical approach to study exciton transport and emission in a single-walled carbon nanotube (SWNT) in the presence of a localized surface-plasmon (SP) mode within a metal nanoparticle interacting via near-field coupling. We derive a set of quantum mechanical equations of motion and approximate rate equations that account for the exciton, SP, and the environmental degrees of freedom. The material equations are complemented by an expression for the radiated power that depends on the exciton and SP populations and coherences, allowing for an examination of the angular distribution of the emitted radiation that would be measured in experiment. Numerical simulations for a (6,5) SWNT and cone-shaped Ag metal tip (MT) have been performed using this methodology. Comparison with physical parameters shows that the near-field interaction between the exciton-SP occurs in a weak coupling regime, with the diffusion processes being much faster than the exciton-SP population exchange. In such a case, the effect of the exciton population transfer to the MT with its subsequent dissipation (i.e., the Förster energy transfer) is to modify the exciton steady state distribution while reducing the equilibration time for excitons to reach a steady sate distribution. We find that the radiation distribution is dominated by SP emission for a SWNT-MT separation of a few tens of nanometers due to the fast SP emission rate, whereas the exciton-SP coherences can cause its rotation.

  11. Spatially resolved localized vibrational mode spectroscopy of carbon in liquid encapsulated Czochralski grown gallium arsenide wafers

    International Nuclear Information System (INIS)

    Yau, Waifan.

    1988-04-01

    Substitutional carbon on an arsenic lattice site is the shallowest and one of the most dominant acceptors in semi-insulating Liquid Encapsulated Czochralski (LEC) GaAs. However, the role of this acceptor in determining the well known ''W'' shape spatial variation of neutral EL2 concentration along the diameter of a LEC wafer is not known. In this thesis, we attempt to clarify the issue of the carbon acceptor's effect on this ''W'' shaped variation by measuring spatial profiles of this acceptor along the radius of three different as-grown LEC GaAs wafers. With localized vibrational mode absorption spectroscopy, we find that the profile of the carbon acceptor is relatively constant along the radius of each wafer. Average values of concentration are 8 x 10E15 cm -3 , 1.1 x 10E15 cm -3 , and 2.2 x 10E15 cm -3 , respectively. In addition, these carbon acceptor LVM measurements indicate that a residual donor with concentration comparable to carbon exists in these wafers and it is a good candidate for the observed neutral EL2 concentration variation. 22 refs., 39 figs

  12. Probing Stress-Induced Optical Birefringence of Glassy Polymers by Whispering Gallery Modes Light Localization.

    Science.gov (United States)

    Milenko, Karolina; Pissadakis, Stavros; Gkantzounis, Georgios; Aluculesei, Alina; Fytas, George

    2017-12-31

    An optical resonance method for the determination of the strain- and stress-optical coefficients of optically transparent polymers is presented and exemplified for monodisperse and bidisperse molecular weight polystyrene (PS). This method employs whispering gallery modes (WGMs) resonation inside a spheroid polymeric cavity, suspended on an optical fiber taper waist, which, in turn, is used for subjecting the polymeric resonator to controlled strain conditions. The wavelength shifts of equal order transverse electric and transverse magnetic polarization WGMs are measured, as well as their relative birefringence versus applied strain. For monodisperse PS microspheroids (2 and 50 kDa) the stress-optical coefficient is negative, contrary to the results for bulk PS in the glassy state indicating different phenyl group orientation of the PS monomer with respect to the strain direction. In the bidisperse (2 and 50 kDa) spheroid with a symmetric monomer composition, local structural irregularities are probably responsible for the observed coupling between WGMs. The method possesses metrological capabilities for probing the molecular orientation of polymer-based resonators.

  13. Electromagnetic-thermal-structural coupling analysis of the ITER edge localized mode coil with flexible supports

    Science.gov (United States)

    Zhang, Shanwen; Song, Yuntao; Tang, Linlin; Wang, Zhongwei; Ji, Xiang; Du, Shuangsong

    2017-05-01

    In a fusion reactor, the edge localized mode (ELM) coil has a mitigating effect on the ELMs of the plasma. The coil is placed close to the plasma between the vacuum vessel and the blanket to reduce its design power and improve its mitigating ability. The coil works in a high-temperature, high-nuclear-heat and high-magnetic-field environment. Due to the existence of outer superconducting coils, the coil is subjected to an alternating electromagnetic force induced by its own alternating current and the outer magnetic field. The design goal for the ELM coil is to maintain its structural integrity in the multi-physical field. Taking as an example the middle ELM coil (with flexible supports) of ITER (the International Thermonuclear Fusion Reactor), an electromagnetic-thermal-structural coupling analysis is carried out using ANSYS. The results show that the flexible supports help the three-layer casing meet the static and fatigue design requirements. The structural design of the middle ELM coil is reasonable and feasible. The work described in this paper provides the theoretical basis and method for ELM coil design.

  14. Non-stationary excitation of two localized spin-wave modes in a nano-contact spin torque oscillator

    Science.gov (United States)

    Consolo, G.; Finocchio, G.; Siracusano, G.; Bonetti, S.; Eklund, A.; Åkerman, J.; Azzerboni, B.

    2013-10-01

    We measure and simulate micromagnetically a framework based upon a nano-contact spin torque oscillator where two distinct localized evanescent spin-wave modes can be detected. The resulting frequency spectrum is composed by two peaks, corresponding to the excited modes, which lie below the ferromagnetic resonance frequency, and a low-frequency tail, which we attribute to the non-stationary switching between these modes. By using Fourier, wavelet, and Hilbert-Huang transforms, we investigate the properties of these modes in time and spatial domains, together with their spatial distribution. The existence of an additional localized mode (which was neither predicted by theory nor by previous numerical and experimental findings) has to be attributed to the large influence of the current-induced Oersted field strength which, in the present setup, is of the same order of magnitude as the external field. As a further consequence, the excited spin-waves, contrarily to what usually assumed, do not possess cylindrical symmetry: the Oersted field induces these modes to be excited at the two opposite sides of the region beneath the nano-contact.

  15. Mixed-symmetry localized modes and breathers in binary mixtures of Bose-Einstein condensates in optical lattices

    International Nuclear Information System (INIS)

    Cruz, H. A.; Brazhnyi, V. A.; Konotop, V. V.; Alfimov, G. L.; Salerno, M.

    2007-01-01

    We study localized modes in binary mixtures of Bose-Einstein condensates embedded in one-dimensional optical lattices. We report a diversity of asymmetric modes and investigate their dynamics. We concentrate on the cases where one of the components is dominant, i.e., has a much larger number of atoms than the other one, and where both components have the numbers of atoms of the same order but different symmetries. In the first case we propose a method of systematically obtaining the modes, considering the ''small'' component as bifurcating from the continuum spectrum. A generalization of this approach combined with the use of the symmetry of the coupled Gross-Pitaevskii equations allows for obtaining breather modes, which are also presented

  16. Direct observation of current in type-I edge-localized-mode filaments on the ASDEX upgrade tokamak

    DEFF Research Database (Denmark)

    Vianello, N.; Zuin, M.; Cavazzana, R.

    2011-01-01

    Magnetically confined plasmas in the high confinement regime are regularly subjected to relaxation oscillations, termed edge localized modes (ELMs), leading to large transport events. Present ELM theories rely on a combined effect of edge current and the edge pressure gradients which result...

  17. Increased electron temperature turbulence during suppression of edge localized mode by resonant magnetic perturbations in the DIII-D tokamak

    Science.gov (United States)

    Sung, C.; Wang, G.; Rhodes, T. L.; Smith, S. P.; Osborne, T. H.; Ono, M.; McKee, G. R.; Yan, Z.; Groebner, R. J.; Davis, E. M.; Zeng, L.; Peebles, W. A.; Evans, T. E.

    2017-11-01

    The first observation of increased electron temperature turbulence during edge localized mode (ELM) suppression by resonant magnetic perturbations (RMPs) is presented. These are long wavelength fluctuations (kθρs ≤ 0.2, where kθ = poloidal wavenumber and ρs = ion sound gyroradius) observed during H-mode plasmas on the DIII-D. This increase occurs only after ELMs are suppressed and are not observed during the initial RMP application. The T˜ e/Te increases ( >60%) are coincident with changes in normalized density and electron temperature gradients in the region from the top of the pedestal outward to the upper portion of the steep edge gradient. Density turbulence (kθρs ≤ 0.4) in this location was also observed to increase only after ELM suppression. These results are significant since they indicate that increased gradient-driven turbulent transport is one possible mechanism to regulate and maintain ELM-free H-mode operation. Investigation of linear stability of drift wave instabilities using the CGYRO code [Candy et al., J. Comput. Phys. 324, 73 (2016)] shows that the dominant mode moves closer to the electron mode branch from the ion mode branch only after ELMs are suppressed, correlated with the increased turbulence. The increased turbulence during ELM suppression, rather than with the initial RMP application, indicates that the often observed RMP induced "density pump-out" cannot be attributed to long wavelength edge turbulence level changes.

  18. Altered intrinsic organisation of brain networks implicated in attentional processes in adult attention-deficit/hyperactivity disorder: a resting-state study of attention, default mode and salience network connectivity.

    Science.gov (United States)

    Sidlauskaite, Justina; Sonuga-Barke, Edmund; Roeyers, Herbert; Wiersema, Jan R

    2016-06-01

    Deficits in task-related attentional engagement in attention-deficit/hyperactivity disorder (ADHD) have been hypothesised to be due to altered interrelationships between attention, default mode and salience networks. We examined the intrinsic connectivity during rest within and between these networks. Six-minute resting-state scans were obtained. Using a network-based approach, connectivity within and between the dorsal and ventral attention, the default mode and the salience networks was compared between the ADHD and control group. The ADHD group displayed hyperconnectivity between the two attention networks and within the default mode and ventral attention network. The salience network was hypoconnected to the dorsal attention network. There were trends towards hyperconnectivity within the dorsal attention network and between the salience and ventral attention network in ADHD. Connectivity within and between other networks was unrelated to ADHD. Our findings highlight the altered connectivity within and between attention networks, and between them and the salience network in ADHD. One hypothesis to be tested in future studies is that individuals with ADHD are affected by an imbalance between ventral and dorsal attention systems with the former playing a dominant role during task engagement, making individuals with ADHD highly susceptible to distraction by salient task-irrelevant stimuli.

  19. Beat-to-Beat Variation in Periodicity of Local Calcium Releases Contributes to Intrinsic Variations of Spontaneous Cycle Length in Isolated Single Sinoatrial Node Cells.

    Directory of Open Access Journals (Sweden)

    Oliver Monfredi

    Full Text Available Spontaneous, submembrane local Ca(2+ releases (LCRs generated by the sarcoplasmic reticulum in sinoatrial nodal cells, the cells of the primary cardiac pacemaker, activate inward Na(+/Ca(2+-exchange current to accelerate the diastolic depolarization rate, and therefore to impact on cycle length. Since LCRs are generated by Ca(2+ release channel (i.e. ryanodine receptor openings, they exhibit a degree of stochastic behavior, manifested as notable cycle-to-cycle variations in the time of their occurrence.The present study tested whether variation in LCR periodicity contributes to intrinsic (beat-to-beat cycle length variability in single sinoatrial nodal cells.We imaged single rabbit sinoatrial nodal cells using a 2D-camera to capture LCRs over the entire cell, and, in selected cells, simultaneously measured action potentials by perforated patch clamp.LCRs begin to occur on the descending part of the action potential-induced whole-cell Ca(2+ transient, at about the time of the maximum diastolic potential. Shortly after the maximum diastolic potential (mean 54±7.7 ms, n = 14, the ensemble of waxing LCR activity converts the decay of the global Ca(2+ transient into a rise, resulting in a late, whole-cell diastolic Ca(2+ elevation, accompanied by a notable acceleration in diastolic depolarization rate. On average, cells (n = 9 generate 13.2±3.7 LCRs per cycle (mean±SEM, varying in size (7.1±4.2 µm and duration (44.2±27.1 ms, with both size and duration being greater for later-occurring LCRs. While the timing of each LCR occurrence also varies, the LCR period (i.e. the time from the preceding Ca(2+ transient peak to an LCR's subsequent occurrence averaged for all LCRs in a given cycle closely predicts the time of occurrence of the next action potential, i.e. the cycle length.Intrinsic cycle length variability in single sinoatrial nodal cells is linked to beat-to-beat variations in the average period of individual LCRs each cycle.

  20. A probabilistic model for the identification of confinement regimes and edge localized mode behavior, with implications to scaling laws

    International Nuclear Information System (INIS)

    Verdoolaege, Geert; Van Oost, Guido

    2012-01-01

    Pattern recognition is becoming an important tool in fusion data analysis. However, fusion diagnostic measurements are often affected by considerable statistical uncertainties, rendering the extraction of useful patterns a significant challenge. Therefore, we assume a probabilistic model for the data and perform pattern recognition in the space of probability distributions. We show the considerable advantage of our method for identifying confinement regimes and edge localized mode behavior, and we discuss the potential for scaling laws.

  1. Enhanced Confinement Scenarios Without Large Edge Localized Modes in Tokamaks: Control, Performance, and Extrapolability Issues for ITER

    Energy Technology Data Exchange (ETDEWEB)

    Maingi, R [PPPL

    2014-07-01

    Large edge localized modes (ELMs) typically accompany good H-mode confinement in fusion devices, but can present problems for plasma facing components because of high transient heat loads. Here the range of techniques for ELM control deployed in fusion devices is reviewed. The two baseline strategies in the ITER baseline design are emphasized: rapid ELM triggering and peak heat flux control via pellet injection, and the use of magnetic perturbations to suppress or mitigate ELMs. While both of these techniques are moderately well developed, with reasonable physical bases for projecting to ITER, differing observations between multiple devices are also discussed to highlight the needed community R & D. In addition, recent progress in ELM-free regimes, namely Quiescent H-mode, I-mode, and Enhanced Pedestal H-mode is reviewed, and open questions for extrapolability are discussed. Finally progress and outstanding issues in alternate ELM control techniques are reviewed: supersonic molecular beam injection, edge electron cyclotron heating, lower hybrid heating and/or current drive, controlled periodic jogs of the vertical centroid position, ELM pace-making via periodic magnetic perturbations, ELM elimination with lithium wall conditioning, and naturally occurring small ELM regimes.

  2. Rock Fracture Toughness Under Mode II Loading: A Theoretical Model Based on Local Strain Energy Density

    Science.gov (United States)

    Rashidi Moghaddam, M.; Ayatollahi, M. R.; Berto, F.

    2018-01-01

    The values of mode II fracture toughness reported in the literature for several rocks are studied theoretically by using a modified criterion based on strain energy density averaged over a control volume around the crack tip. The modified criterion takes into account the effect of T-stress in addition to the singular terms of stresses/strains. The experimental results are related to mode II fracture tests performed on the semicircular bend and Brazilian disk specimens. There are good agreements between theoretical predictions using the generalized averaged strain energy density criterion and the experimental results. The theoretical results reveal that the value of mode II fracture toughness is affected by the size of control volume around the crack tip and also the magnitude and sign of T-stress.

  3. Cladding mode coupling in highly localized fiber Bragg gratings: modal properties and transmission spectra.

    Science.gov (United States)

    Thomas, Jens; Jovanovic, Nemanja; Becker, Ria G; Marshall, Graham D; Withford, Michael J; Tünnermann, Andreas; Nolte, Stefan; Steel, M J

    2011-01-03

    The spectral characteristics of a fiber Bragg grating (FBG) with a transversely inhomogeneous refractive index profile, differs considerably from that of a transversely uniform one. Transmission spectra of inhomogeneous and asymmetric FBGs that have been inscribed with focused ultrashort pulses with the so-called point-by-point technique are investigated. The cladding mode resonances of such FBGs can span a full octave in the spectrum and are very pronounced (deeper than 20dB). Using a coupled-mode approach, we compute the strength of resonant coupling and find that coupling into cladding modes of higher azimuthal order is very sensitive to the position of the modification in the core. Exploiting these properties allows precise control of such reflections and may lead to many new sensing applications.

  4. Sex commonalities and differences in the relationship between resilient personality and the intrinsic connectivity of the salience and default mode networks

    Science.gov (United States)

    Kilpatrick, Lisa A.; Istrin, Joshua J.; Gupta, Arpana; Naliboff, Bruce; Tillisch, Kirsten; Labus, Jennifer S.; Mayer, Emeran A.

    2016-01-01

    Increased resilience is associated with better health outcomes and reduced morbidity in response to injury and homeostatic perturbations. Proper functioning of the salience network (SN) and modulation of the default mode network (DMN) by SN may play a role in adaptively responding to stress. Here, we demonstrate that resilient personality in healthy subjects is associated with SN and DMN connectivity patterns and that these patterns are influenced by sex. While connectivity of SN with several brain regions including right anterior insula was significantly associated with resilient personality in both men and women, results suggest that increased functional integration of anterior DMN preferentially benefits women while increased functional integration of posterior DMN preferentially benefits men in terms of resilience. These findings may relate to previous demonstrations that men and women engage different information processing and behavioral strategies to achieve resilience and highlight the importance of considering sex in resilience research. PMID:26440126

  5. Polaritonic normal-mode splitting and light localization in a one-dimensional nanoguide

    NARCIS (Netherlands)

    Haakh, Harald R.; Faez, Sanli; Sandoghdar, Vahid

    2016-01-01

    We theoretically investigate the interaction of light and a collection of emitters in a subwavelength one-dimensional medium (nanoguide), where enhanced emitter-photon coupling leads to efficient multiple scattering of photons. We show that the spectrum of the transmitted light undergoes normal-mode

  6. Multi-Mode Estimation for Small Fixed Wing Unmanned Aerial Vehicle Localization Based on a Linear Matrix Inequality Approach.

    Science.gov (United States)

    Elzoghby, Mostafa; Li, Fu; Arafa, Ibrahim I; Arif, Usman

    2017-04-18

    Information fusion from multiple sensors ensures the accuracy and robustness of a navigation system, especially in the absence of global positioning system (GPS) data which gets degraded in many cases. A way to deal with multi-mode estimation for a small fixed wing unmanned aerial vehicle (UAV) localization framework is proposed, which depends on utilizing a Luenberger observer-based linear matrix inequality (LMI) approach. The proposed estimation technique relies on the interaction between multiple measurement modes and a continuous observer. The state estimation is performed in a switching environment between multiple active sensors to exploit the available information as much as possible, especially in GPS-denied environments. Luenberger observer-based projection is implemented as a continuous observer to optimize the estimation performance. The observer gain might be chosen by solving a Lyapunov equation by means of a LMI algorithm. Convergence is achieved by utilizing the linear matrix inequality (LMI), based on Lyapunov stability which keeps the dynamic estimation error bounded by selecting the observer gain matrix (L). Simulation results are presented for a small UAV fixed wing localization problem. The results obtained using the proposed approach are compared with a single mode Extended Kalman Filter (EKF). Simulation results are presented to demonstrate the viability of the proposed strategy.

  7. Intrinsic Functional Connectivity in Salience and Default Mode Networks and Aberrant Social Processes in Youth at Ultra-High Risk for Psychosis

    Science.gov (United States)

    Pelletier-Baldelli, Andrea; Bernard, Jessica A.; Mittal, Vijay A.

    2015-01-01

    Social processes are key to navigating the world, and investigating their underlying mechanisms and cognitive architecture can aid in understanding disease states such as schizophrenia, where social processes are highly impacted. Evidence suggests that social processes are impaired in individuals at ultra high-risk for the development of psychosis (UHR). Understanding these phenomena in UHR youth may clarify disease etiology and social processes in a period that is characterized by significantly fewer confounds than schizophrenia. Furthermore, understanding social processing deficits in this population will help explain these processes in healthy individuals. The current study examined resting state connectivity of the salience (SN) and default mode networks (DMN) in association with facial emotion recognition (FER), an integral aspect of social processes, as well as broader social functioning (SF) in UHR individuals and healthy controls. Consistent with the existing literature, UHR youth were impaired in FER and SF when compared with controls. In the UHR group, we found increased connectivity between the SN and the medial prefrontal cortex, an area of the DMN relative to controls. In UHR youth, the DMN exhibited both positive and negative correlations with the somatosensory cortex/cerebellum and precuneus, respectively, which was linked with better FER performance. For SF, results showed that sensory processing links with the SN might be important in allowing for better SF for both groups, but especially in controls where sensory processing is likely to be unimpaired. These findings clarify how social processing deficits may manifest in psychosis, and underscore the importance of SN and DMN connectivity for social processing more generally. PMID:26252525

  8. Learning intrinsic excitability in medium spiny neurons.

    Science.gov (United States)

    Scheler, Gabriele

    2013-01-01

    We present an unsupervised, local activation-dependent learning rule for intrinsic plasticity (IP) which affects the composition of ion channel conductances for single neurons in a use-dependent way. We use a single-compartment conductance-based model for medium spiny striatal neurons in order to show the effects of parameterization of individual ion channels on the neuronal membrane potential-curent relationship (activation function). We show that parameter changes within the physiological ranges are sufficient to create an ensemble of neurons with significantly different activation functions. We emphasize that the effects of intrinsic neuronal modulation on spiking behavior require a distributed mode of synaptic input and can be eliminated by strongly correlated input. We show how modulation and adaptivity in ion channel conductances can be utilized to store patterns without an additional contribution by synaptic plasticity (SP). The adaptation of the spike response may result in either "positive" or "negative" pattern learning. However, read-out of stored information depends on a distributed pattern of synaptic activity to let intrinsic modulation determine spike response. We briefly discuss the implications of this conditional memory on learning and addiction.

  9. Pattern recognition in spaces of probability distributions for the analysis of edge-localized modes in tokamak plasmas

    International Nuclear Information System (INIS)

    Shabbir, Aqsa

    2016-01-01

    In this doctoral work, pattern recognition techniques are developed and applied to data from tokamak plasmas, in order to contribute to a systematic analysis of edge-localized modes (ELMs). We employ probabilistic models for a quantitative data description geared towards an enhanced systematization of ELM phenomenology. Hence, we start from the point of view that the fundamental object resulting from the observation of a system is a probability distribution, with every single measurement providing a sample from this distribution. In exploring the patterns emerging from the various ELM regimes and relations, we need methods that can handle the intrinsic probabilistic nature of the data. The original contributions of this work are twofold. First, several novel pattern recognition methods in non-Euclidean spaces of probability distribution functions (PDFs) are developed and validated. The second main contribution lies in the application of these and other techniques to a systematic analysis of ELMs in tokamak plasmas. In regard to the methodological aims of the work, we employ the framework of information geometry to develop pattern visualization and classification methods in spaces of probability distributions. In information geometry, a family of probability distributions is considered as a Riemannian manifold. Every point on the manifold represents a single PDF and the distribution parameters provide local coordinates on the manifold. The Fisher information plays the role of a Riemannian metric tensor, enabling calculation of geodesic curves on the surface. The length of such curves yields the geodesic distance (GD) on probabilistic manifolds, which is a natural similarity (distance) measure between PDFs. Equipped with a suitable distance measure, we extrapolate several distance-based pattern recognition methods to the manifold setting. This includes k-nearest neighbor (kNN) and conformal predictor (CP) methods for classification, as well as multidimensional

  10. Stability and phase transition of localized modes in Bose–Einstein condensates with both two- and three-body interactions

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Xiao-Dong; Ai, Qing; Zhang, Mei; Xiong, Jun, E-mail: junxiong@bnu.edu.cn; Yang, Guo-Jian; Deng, Fu-Guo

    2015-09-15

    We investigate the stability and phase transition of localized modes in Bose–Einstein Condensates (BECs) in an optical lattice with the discrete nonlinear Schrödinger model by considering both two- and three-body interactions. We find that there are three types of localized modes, bright discrete breather (DB), discrete kink (DK), and multi-breather (MUB). Moreover, both two- and three-body on-site repulsive interactions can stabilize DB, while on-site attractive three-body interactions destabilize it. There is a critical value for the three-body interaction with which both DK and MUB become the most stable ones. We give analytically the energy thresholds for the destabilization of localized states and find that they are unstable (stable) when the total energy of the system is higher (lower) than the thresholds. The stability and dynamics characters of DB and MUB are general for extended lattice systems. Our result is useful for the blocking, filtering, and transfer of the norm in nonlinear lattices for BECs with both two- and three-body interactions.

  11. Observation of a High Performance Operating Regime with Small Edge-Localized Modes in the National Spherical Torus Experiment

    International Nuclear Information System (INIS)

    Maingi, R.; Tritz, K.; Fredrickson, E.D.; Menard, J.E.; Sabbagh, S.A.; Stutman, D.; Bell, M.G.; Bell, R.E.; Bush, C.E.; Gates, D.A.; Johnson, D.W.; Kaita, R.; Kaye, S.M.; Kugel, H.W.; LeBlanc, B.P.; Mueller, D.; Raman, R.; Roquemore, A.L.; Soukhanovskii, V.A.

    2004-01-01

    We report observation of a high performance scenario in the National Spherical Torus Experiment with very small edge-localized modes (ELMs). These ELMs have no measurable impact on stored energy and are consistent with high bootstrap current operation with line average density approaching Greenwald scaling. The ELM perturbation is observed to typically originate near the lower divertor region, as opposed to the outer midplane for ELMs described in the literature. If extrapolable, this scenario would provide an attractive operating regime for next step fusion experiments

  12. Feasibility of A-mode ultrasound attenuation as a monitoring method of local hyperthermia treatment.

    Science.gov (United States)

    Manaf, Noraida Abd; Aziz, Maizatul Nadwa Che; Ridzuan, Dzulfadhli Saffuan; Mohamad Salim, Maheza Irna; Wahab, Asnida Abd; Lai, Khin Wee; Hum, Yan Chai

    2016-06-01

    Recently, there is an increasing interest in the use of local hyperthermia treatment for a variety of clinical applications. The desired therapeutic outcome in local hyperthermia treatment is achieved by raising the local temperature to surpass the tissue coagulation threshold, resulting in tissue necrosis. In oncology, local hyperthermia is used as an effective way to destroy cancerous tissues and is said to have the potential to replace conventional treatment regime like surgery, chemotherapy or radiotherapy. However, the inability to closely monitor temperature elevations from hyperthermia treatment in real time with high accuracy continues to limit its clinical applicability. Local hyperthermia treatment requires real-time monitoring system to observe the progression of the destroyed tissue during and after the treatment. Ultrasound is one of the modalities that have great potential for local hyperthermia monitoring, as it is non-ionizing, convenient and has relatively simple signal processing requirement compared to magnetic resonance imaging and computed tomography. In a two-dimensional ultrasound imaging system, changes in tissue microstructure during local hyperthermia treatment are observed in terms of pixel value analysis extracted from the ultrasound image itself. Although 2D ultrasound has shown to be the most widely used system for monitoring hyperthermia in ultrasound imaging family, 1D ultrasound on the other hand could offer a real-time monitoring and the method enables quantitative measurement to be conducted faster and with simpler measurement instrument. Therefore, this paper proposes a new local hyperthermia monitoring method that is based on one-dimensional ultrasound. Specifically, the study investigates the effect of ultrasound attenuation in normal and pathological breast tissue when the temperature in tissue is varied between 37 and 65 °C during local hyperthermia treatment. Besides that, the total protein content measurement was also

  13. Suppression of large edge localized modes with edge resonant magnetic fields in high confinement DIII-D plasmas

    International Nuclear Information System (INIS)

    Thomas, P.R.; Becoulet, M.; Evans, T.E.; Osborne, T.H.; Groebner, R.J.; Jackson, G.L.; Haye, R.J. La; Schaffer, M.J.; West, W.P.; Moyer, R.A.; Rhodes, T.L.; Rudakov, D.L.; Watkins, J.G.; Boedo, J.A.; Doyle, E.J.; Wang, G.; Zeng, L.; Fenstermacher, M.E.; Groth, M.; Lasnier, C.J.; Finken, K.H.; Harris, J.H.; Pretty, D.G.; Masuzaki, S.; Ohyabu, N.; Reimerdes, H.; Wade, M.R.

    2005-01-01

    Large divertor heat pulses due to Type-I edge localized modes (ELMs) have been eliminated reproducibly in DIII-D with small dc currents driven in a simple magnetic perturbation coil. The current required to eliminate all but a few isolated Type-I ELMs, during a coil pulse, is less than 0.4% of plasma current. Modelling shows that the perturbation fields resonate with plasma flux surfaces across most of the pedestal region (0.9 ≤ N ≤ 1.0), when q95 = 3.7±0.2 creating small remnant magnetic islands surrounded by weakly stochastic field lines. The stored energy, N , H-mode quality factor and global energy confinement time are unaltered by the magnetic perturbation. At high collisionality (ν* ∼0.5-1), there is no obvious effect of the perturbation on the edge profiles and yet ELMs are suppressed, nearly completely, for up to 9τ E . At low collisionality (ν* <0.1), there is a density pump-out and complete ELM suppression, reminiscent of the DIIID QH- mode. Other differences, specifically in the resonance condition and the magnetic fluctuations, suggest that different mechanisms are at play in the different collisionality regimes. In addition to a description and interpretation of the DIIID data, the application of this method to ELM control on other machines, such as JET and ITER will be discussed. (author)

  14. Characterization of failure modes in deep UV and deep green LEDs utilizing advanced semiconductor localization techniques.

    Energy Technology Data Exchange (ETDEWEB)

    Tangyunyong, Paiboon; Miller, Mary A.; Cole, Edward Isaac, Jr.

    2012-03-01

    We present the results of a two-year early career LDRD that focused on defect localization in deep green and deep ultraviolet (UV) light-emitting diodes (LEDs). We describe the laser-based techniques (TIVA/LIVA) used to localize the defects and interpret data acquired. We also describe a defect screening method based on a quick electrical measurement to determine whether defects should be present in the LEDs. We then describe the stress conditions that caused the devices to fail and how the TIVA/LIVA techniques were used to monitor the defect signals as the devices degraded and failed. We also describe the correlation between the initial defects and final degraded or failed state of the devices. Finally we show characterization results of the devices in the failed conditions and present preliminary theories as to why the devices failed for both the InGaN (green) and AlGaN (UV) LEDs.

  15. Characterization of plasma jet ejected from a parallel-plate rail gun for simulating edge localized mode

    International Nuclear Information System (INIS)

    Chung, K.S.; Chung, Kyoung-Jae; Jung, B.K.; Hwang, Y.S.

    2013-01-01

    Highlights: • A small plasma gun is constructed to study edge localized mode. • A plasma jet ejected from the gun is characterized with a quadruple Langmuir probe. • The device and diagnostics are suitable for research about the control of plasma jet. -- Abstract: A small plasma gun with parallel-plate configuration is fabricated to generate a bunch of plasma which is similar to ELM (edge localized mode) plasma, by taking advantages of its simplicity and cost-effectiveness. Prior to explore how to control the ELM-like plasma so as to relieve heat load on the divertor target, characteristics of a plasma jet ejected from the plasma gun are investigated using a quadruple Langmuir probe which is appropriate for measuring rapidly varying plasma parameters such as electron density, temperature, and ion velocity at the same time. The plasma density and ion velocity measured at 112 mm away from the exit are 3 × 10 19 m −3 and 11 km/s, respectively, which seem to be suitable for investigating next step research on the control of ELM-like plasma using various methods such as electromagnetic waves and high-voltage pulses. Also, the quadruple Langmuir probe is proven to be adequate for use in such experiments

  16. Novel Applicators for Local Microwave Hyperthermia Based on Zeroth-Order Mode Resonator Metamaterial

    Directory of Open Access Journals (Sweden)

    David Vrba

    2014-01-01

    Full Text Available It is demonstrated that a theory of zero-order mode resonator (ZOR metamaterial (MTM structure can be used for the development of a novel class of applicators for microwave thermotherapy, for example, for hyperthermia in cancer treatment or for physiotherapy. The main idea of creating such an applicator is to generate and radiate a plane electromagnetic (EM wave into the treated biological tissue, at least in a certain extent. The main aim of this paper is to investigate whether an EM wave generated by ZOR MTM structure and emitted into the biological tissue can produce a homogeneous SAR distribution in the planes parallel to the applicator aperture and achieve a penetration depth approaching the theoretical limit represented by SAR distribution and penetration depth of an ideal EM plane wave. EM field distribution inside a virtual phantom of the treated region generated by the applicator that is based on the proposed ZOR MTM principle is investigated using a well-proven full-wave commercial simulation tool. The proposed applicator type shows both a low unwanted leaked electromagnetic field and a fairly homogeneous electric field in its aperture as well as in the virtual phantom of the treated region.

  17. TRACKING DOWN LOCALIZED MODES IN PT-SYMMETRIC HAMILTONIANS UNDER THE INFLUENCE OF A COMPETING NONLINEARITY

    Directory of Open Access Journals (Sweden)

    Bijan Bagchi

    2014-04-01

    Full Text Available The relevance of parity and time reversal (PT-symmetric structures in optical systems has been known for some time with the correspondence existing between the Schrödinger equation and the paraxial equation of diffraction, where the time parameter represents the propagating distance and the refractive index acts as the complex potential. In this paper, we systematically analyze a normalized form of the nonlinear Schrödinger system with two new families of PT-symmetric potentials in the presence of competing nonlinearities. We generate a class of localized eigenmodes and carry out a linear stability analysis on the solutions. In particular, we find an interesting feature of bifurcation characterized by the parameter of perturbative growth rate passing through zero, where a transition to imaginary eigenvalues occurs.

  18. Automatic bone outer contour extraction from B-modes ultrasound images based on local phase symmetry and quadratic polynomial fitting

    Science.gov (United States)

    Karlita, Tita; Yuniarno, Eko Mulyanto; Purnama, I. Ketut Eddy; Purnomo, Mauridhi Hery

    2017-06-01

    Analyzing ultrasound (US) images to get the shapes and structures of particular anatomical regions is an interesting field of study since US imaging is a non-invasive method to capture internal structures of a human body. However, bone segmentation of US images is still challenging because it is strongly influenced by speckle noises and it has poor image quality. This paper proposes a combination of local phase symmetry and quadratic polynomial fitting methods to extract bone outer contour (BOC) from two dimensional (2D) B-modes US image as initial steps of three-dimensional (3D) bone surface reconstruction. By using local phase symmetry, the bone is initially extracted from US images. BOC is then extracted by scanning one pixel on the bone boundary in each column of the US images using first phase features searching method. Quadratic polynomial fitting is utilized to refine and estimate the pixel location that fails to be detected during the extraction process. Hole filling method is then applied by utilize the polynomial coefficients to fill the gaps with new pixel. The proposed method is able to estimate the new pixel position and ensures smoothness and continuity of the contour path. Evaluations are done using cow and goat bones by comparing the resulted BOCs with the contours produced by manual segmentation and contours produced by canny edge detection. The evaluation shows that our proposed methods produces an excellent result with average MSE before and after hole filling at the value of 0.65.

  19. (2+1)-Dimensional Spatial Localized Modes in Cubic-Quintic Nonlinear Media with the Script PScript T-Symmetric Potentials

    Science.gov (United States)

    Chen, Yi-Xiang; Xu, Zhou-Xiang; Jiang, Yun-Feng; Shi, Jin; Xu, Fang-Qian

    2015-07-01

    We obtain exact spatial localized mode solutions of a (2+1)-dimensional nonlinear Schrödinger equation with constant diffraction and cubic-quintic nonlinearity in Script PScript T-symmetric potential, and study the linear stability of these solutions. Based on these results, we further derive exact spatial localized mode solutions in a cubic-quintic medium with harmonic and Script PScript T-symmetric potentials. Moreover, the dynamical behaviors of spatial localized modes in the exponential diffraction decreasing waveguide and the periodic distributed amplification system are investigated. Supported by the Project of Technology Office in Zhejiang Province under Grant No. 2014C32006, the Special Foundation for theoretical physics Research Program of China under Grant No. 11447124, National Natural Science Foundation of China under Grant No. 11374254 and the Higher School Visiting Scholar Development under Grant No. FX2013103

  20. Effects of stimulus mode and ambient temperature on cerebral responses to local thermal stimulation: An EEG study.

    Science.gov (United States)

    Lv, Bin; Su, Chang; Yang, Lei; Wu, Tongning

    2017-03-01

    The physiological responses to human thermal stimulation have been widely investigated, but most of them are mainly concerned about the whole body thermal stimulation. In this study, we investigated the effects of stimulus mode and ambient temperature on cerebral responses during local thermal stimulation on hand. The left hands were stimulated by metal thermostat based and thermostatic water based stimulators at different stimulated temperatures (38°C, 40°C, 42°C and 44°C) and different ambient temperatures (25°C and 32°C). EEG data were recorded over the whole brain during the experiments. Then the statistical comparisons were conducted on the EEG relative power among different experimental sessions. We observed that EEG activities were alternated between thermal stimulated periods and the baseline in all four frequency bands. And there was a higher percentage of delta band power in the right temporal and parietal regions under the ambient temperature of 32°C while compared to 25°C. In addition, the theta band activity under the metal based stimulation showed significantly higher EEG relative power than that under the water based stimulation over the whole brain. Compared with the water based stimulation, there was a lower EEG relative power of the beta band activity during the metal based stimulation in the bilateral frontal and right temporal regions. The experimental results suggested that the neural physiological responses in different EEG frequency bands were sensitive to different influence factors during the local hand thermal stimulation. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Live-cell Imaging of Fungal Cells to Investigate Modes of Entry and Subcellular Localization of Antifungal Plant Defensins.

    Science.gov (United States)

    Islam, Kazi T; Shah, Dilip M; El-Mounadi, Kaoutar

    2017-12-24

    Small cysteine-rich defensins are one of the largest groups of host defense peptides present in all plants. Many plant defensins exhibit potent in vitro antifungal activity against a broad-spectrum of fungal pathogens and therefore have the potential to be used as antifungal agents in transgenic crops. In order to harness the full potential of plant defensins for diseases control, it is crucial to elucidate their mechanisms of action (MOA). With the advent of advanced microscopy techniques, live-cell imaging has become a powerful tool for understanding the dynamics of the antifungal MOA of plant defensins. Here, a confocal microscopy based live-cell imaging method is described using two fluorescently labeled plant defensins (MtDef4 and MtDef5) in combination with vital fluorescent dyes. This technique enables real-time visualization and analysis of the dynamic events of MtDef4 and MtDef5 internalization into fungal cells. Importantly, this assay generates a wealth of information including internalization kinetics, mode of entry and subcellular localization of these peptides. Along with other cell biological tools, these methods have provided critical insights into the dynamics and complexity of the MOA of these peptides. These tools can also be used to compare the MOA of these peptides against different fungi.

  2. Temporal evolutions of electron temperature and density with edge localized mode in the JT-60U divertor plasma

    International Nuclear Information System (INIS)

    Nakano, T; Kubo, H; Asakura, N

    2010-01-01

    From the intensity ratios of the three He I lines measured at 20 kHz, the temporal evolutions of the electron temperature and density during and after the power and the particle flow into the divertor plasma caused by edge localized modes are determined. The electron temperature increases from 70 eV to 80 eV with increasing D α intensity. Then, at the peak of D α intensity, the electron temperature starts decreasing down to 60 eV. The electron density increases from 0.1 x 10 19 m -3 to 0.3 x 10 19 m -3 with increasing D α intensity, and then starts to decrease more gradually compared with the electron temperature after the peak of D α intensity. It is interpreted that the increase of the electron temperature is ascribed to the power and the particle flow into the divertor plasma, and that the decrease of the electron temperature and the increase of the electron density are ascribed to the ionization of the recycled neutrals, which consumes the electron energy and produces electrons.

  3. Local stochastic subgrid-scale modeling for a one dimensional shallow water model using stochastic mode reduction

    Science.gov (United States)

    Zacharuk, Matthias; Stamen, Dolaptchiev; Ulrich, Achatz; Ilya, Timofeyev

    2016-04-01

    Due to the finite spatial resolution in numerical atmospheric models subgrid-scale (SGS) processes are excluded. A SGS parameterization of these excluded processes might improve the model on all scales. To parameterize the SGS processes we choose the MTV stochastic mode reduction (Majda, Timofeyev, Vanden-Eijnden 2001, A mathematical framework for stochastic climate models. Commun. Pure Appl. Math., 54:891-974). For this the model is separated into fast and slow processes. Using the statistics of the fast processes, a SGS parameterization is found. To identify fast processes the state vector of the model is separated into two state vectors. One vector is the average of the full model state vector in a coarse grid cell. The other describes SGS processes which are defined as the deviation of the full state vector from the coarse cell average. If the SGS vector decorrelates faster in time than the coarse grid vector, the interactions of SGS processes in the equation of the SGS processes are replaced by a local Ornstein-Uhlenbeck process. Afterwards the MTV SGS parameterization can be derived. This method was successfully applied on the Burgers-equation (Dolaptchiev et al. 2013, Stochastic closure for local averages in the finite-difference discretization of the forced Burgers equation. Theor. Comp. Fluid Dyn., 27:297-317). In this study we consider a more atmosphere like model and choose a model of the one dimensional shallow water equations (SWe). It will be shown, that the fine state vector decorrelates faster than the coarse state vector. Due to the non-polynomial form of the SWe in flux formulation an approximation of all 1/h (h = fluid depth) terms needs to be done, except of the interactions between coarse state vector to coarse state vector. It will be shown, that this approximation has only minor impact on the model results. In the following the model with the local Ornstein-Uhlenbeck process approximation of SGS interactions is analyzed and compared to the

  4. Local stochastic subgrid-scale modeling for a one dimensional shallow water model using stochastic mode reduction

    Science.gov (United States)

    Zacharuk, Matthias; Dolaptchiev, Stamen; Achatz, Ulrich; Timofeyev, Ilya

    2017-04-01

    Due to the finite spatial resolution in numerical atmospheric models, subgrid-scale (SGS) processes arise. A SGS parameterization of these excluded processes might improve the model on all scales. In this study we present a model derived parameterization of these processes for the one dimensional shallow water equations. To parameterize the SGS processes we choose the MTV stochastic mode reduction (Majda, Timofeyev, Vanden-Eijnden 2001, A mathematical framework for stochastic climate models. Commun. Pure Appl. Math., 54:891-974). For this the model is separated into fast and slow processes. Using the statistics of the fast processes, a SGS parameterization is found. To identify fast processes the state vector of the model is separated into two state vectors. One vector is the average of the full model state vector in a coarse grid cell. The other describes SGS processes which are defined as the deviation of the full state vector from the coarse cell average. If the SGS vector decorrelates faster in time than the coarse grid vector, the stochastic MTV SGS parameterization can be derived from the model equation, which is the advantage of this method compared to others. So far the method was successfully applied on the Burgers-equation (Dolaptchiev et al. 2013, Stochastic closure for local averages in the finite-difference discretization of the forced Burgers equation. Theor. Comp. Fluid Dyn., 27:297-317). To apply the method onto the one the dimensional shallow water equations, we choose a local approach of the fine variable self-interactions. With this, we are able to derive a local SGS parameterization using MTV's method leading to a closed model wrt. the coarse variable. We show, that this model is able to fix the energy decrease for high wave numbers which appears at the coarse resolution model with neglected SGS parameterization. In the future we plan to extend the model to two dimensions and multiple layers. Perspectively, the method can be used to derive a

  5. Random nanolasing in the Anderson localized regime

    DEFF Research Database (Denmark)

    Liu, Jin; Garcia, P. D.; Ek, Sara

    2014-01-01

    multiple scattering. The applicability of random lasers has been limited due to multidirectional emission, lack of tunability, and strong mode competition with chaotic fluctuations due to a weak mode confinement. The regime of Anderson localization of light has been proposed for obtaining stable multimode...... random lasing, and initial work concerned macroscopic one-dimensional layered media. Here, we demonstrate on-chip random nanolasers where the cavity feedback is provided by the intrinsic disorder. The strong confinement achieved by Anderson localization reduces the spatial overlap between lasing modes...

  6. Edge localized modes control by resonant magnetic perturbations; Controle des instabilites de bord par perturbations magnetiques resonantes

    Energy Technology Data Exchange (ETDEWEB)

    Nardon, E

    2007-10-15

    The present work is dedicated to one of the most promising methods of control of the ELMs (Edge Localized Modes), based on a system of coils producing Resonant Magnetic Perturbations (RMPs). Our main objectives are, on the one hand, to improve the physical understanding of the mechanisms at play, and on the other hand to propose a concrete design of ELMs control coils for ITER. In order to calculate and analyze the magnetic perturbations produced by a given set of coils, we have developed the ERGOS code. The first ERGOS calculation was for the DIII-D ELMs control coils, the I-coils. It showed that they produce magnetic islands chains which overlap at the edge of the plasma, resulting in the ergodization of the magnetic field. We have then used ERGOS for the modelling of the experiments on ELMs control using the error field correction coils at JET and MAST. In the case of JET, we have shown the existence of a correlation between the mitigation of the ELMs and the ergodization of the magnetic field at the edge, in agreement with the DIII-D result. In order to design the ELMs control coils for ITER we have used ERGOS intensively, taking the case of the DIII-D I-coils as a reference. Three candidate designs came out, which we presented at the ITER Design Review, in 2007. Recently, the ITER management decided to provide a budget for building ELMs control coils, the design of which remains to be chosen between two of the three options that we proposed. Finally, in order to understand better the non-linear magnetohydrodynamics phenomena taking place in ELMs control by RMPs, we performed numerical simulations, in particular with the JOREK code for a DIII-D case. The simulations reveal the existence of convection cells induced at the edge by the magnetic perturbations, and the possible screening of the RMPs in presence of rotation.

  7. Magnetic topology changes induced by lower hybrid waves and their profound effect on edge-localized modes in the EAST tokamak.

    Science.gov (United States)

    Liang, Y; Gong, X Z; Gan, K F; Gauthier, E; Wang, L; Rack, M; Wang, Y M; Zeng, L; Denner, P; Wingen, A; Lv, B; Ding, B J; Chen, R; Hu, L Q; Hu, J S; Liu, F K; Jie, Y X; Pearson, J; Qian, J P; Shan, J F; Shen, B; Shi, T H; Sun, Y; Wang, F D; Wang, H Q; Wang, M; Wu, Z W; Zhang, S B; Zhang, T; Zhang, X J; Yan, N; Xu, G S; Guo, H Y; Wan, B N; Li, J G

    2013-06-07

    Strong mitigation of edge-localized modes has been observed on Experimental Advanced Superconducting Tokamak, when lower hybrid waves (LHWs) are applied to H-mode plasmas with ion cyclotron resonant heating. This has been demonstrated to be due to the formation of helical current filaments flowing along field lines in the scrape-off layer induced by LHW. This leads to the splitting of the outer divertor strike points during LHWs similar to previous observations with resonant magnetic perturbations. The change in the magnetic topology has been qualitatively modeled by considering helical current filaments in a field-line-tracing code.

  8. The intrinsically disordered structural platform of the plant defence hub protein RPM1-interacting protein 4 provides insights into its mode of action in the host-pathogen interface and evolution of the nitrate-induced domain protein family.

    Science.gov (United States)

    Sun, Xiaolin; Greenwood, David R; Templeton, Matthew D; Libich, David S; McGhie, Tony K; Xue, Bin; Yoon, Minsoo; Cui, Wei; Kirk, Christopher A; Jones, William T; Uversky, Vladimir N; Rikkerink, Erik H A

    2014-09-01

    Arabidopsis thaliana (At) RPM1-interacting protein 4 (RIN4), targeted by many defence-suppressing bacterial type III effectors and monitored by several resistance proteins, regulates plant immune responses to pathogen-associated molecular patterns and type III effectors. Little is known about the overall protein structure of AtRIN4, especially in its unbound form, and the relevance of structure to its diverse biological functions. AtRIN4 contains two nitrate-induced (NOI) domains and is a member of the NOI family. Using experimental and bioinformatic approaches, we demonstrate that the unbound AtRIN4 is intrinsically disordered under physiological conditions. The intrinsically disordered polypeptide chain of AtRIN4 is interspersed with molecular recognition features (MoRFs) and anchor-identified long-binding regions, potentially allowing it to undergo disorder-to-order transitions upon binding to partner(s). A poly-l-proline II structure, often responsible for protein recognition, is also identified in AtRIN4. By performing bioinformatics analyses on RIN4 homologues from different plant species and the NOI proteins from Arabidopsis, we infer the conservation of intrinsic disorder, MoRFs and long-binding regions of AtRIN4 in other plant species and the NOI family. Intrinsic disorder and MoRFs could provide RIN4 proteins with the binding promiscuity and plasticity required to act as hubs in a pivotal position within plant defence signalling cascades. © 2014 FEBS.

  9. Reduction of edge localized mode intensity on DIII-D by on-demand triggering with high frequency pellet injection and implications for ITERa)

    Science.gov (United States)

    Baylor, L. R.; Commaux, N.; Jernigan, T. C.; Meitner, S. J.; Combs, S. K.; Isler, R. C.; Unterberg, E. A.; Brooks, N. H.; Evans, T. E.; Leonard, A. W.; Osborne, T. H.; Parks, P. B.; Snyder, P. B.; Strait, E. J.; Fenstermacher, M. E.; Lasnier, C. J.; Moyer, R. A.; Loarte, A.; Huijsmans, G. T. A.; Futatani, S.

    2013-08-01

    The injection of small deuterium pellets at high repetition rates up to 12× the natural edge localized mode (ELM) frequency has been used to trigger high-frequency ELMs in otherwise low natural ELM frequency H-mode deuterium discharges in the DIII-D tokamak [J. L. Luxon and L. G. Davis, Fusion Technol. 8, 441 (1985)]. The resulting pellet-triggered ELMs result in up to 12× lower energy and particle fluxes to the divertor than the natural ELMs. The plasma global energy confinement and density are not strongly affected by the pellet perturbations. The plasma core impurity density is strongly reduced with the application of the pellets. These experiments were performed with pellets injected from the low field side pellet in plasmas designed to match the ITER baseline configuration in shape and normalized β operation with input heating power just above the H-mode power threshold. Nonlinear MHD simulations of the injected pellets show that destabilization of ballooning modes by a local pressure perturbation is responsible for the pellet ELM triggering. This strongly reduced ELM intensity shows promise for exploitation in ITER to control ELM size while maintaining high plasma purity and performance.

  10. Transport barriers and edge localized modes-like bursts in a plasma model with turbulent equipartition profiles (Erratum in Phys. Plasmas v. 9, 3804 (2003))

    DEFF Research Database (Denmark)

    Naulin, V.; Juul Rasmussen, J.; Nycander, J.

    2003-01-01

    Self-consistent development of transport barriers is investigated analytically and numerically in flux driven interchange turbulence with highly intermittent turbulent fluxes. Numerical simulations on a bounded domain show turbulence leading to a homogenization of Lagrangian invariants by mixing,......, and constitute transport barriers for the turbulent fluxes, but are intermittently disrupted by strong bursts in the transport, which may be related to the strong edge localized modes observed in toroidal devices. (C) 2003 American Institute of Physics....

  11. Short-term forecasting of high resolution local DNI maps with multiple fish-eye cameras in stereoscopic mode

    Science.gov (United States)

    Blanc, Philippe; Massip, Pierre; Kazantzidis, Andreas; Tzoumanikas, Panagiotis; Kuhn, Pascal; Wilbert, Stefan; Schüler, David; Prahl, Christoph

    2017-06-01

    Nowcasting of high resolution maps of direct normal irradiance (DNI) is of interest to efficiently operate Concentrated Solar Power plants. The paper presents a state-of-the-art and innovative methodology, developed in the framework of the FP7 DNICast project, to derive nowcasting of DNI maps from fish-eye cameras in stereoscopic mode. This methodology has been applied at the Plataforma Solar de Almeria: fish-eye cameras at distances from each other between 500 m and 900 m have been used in stereoscopic mode to produce nowcasted 1-min time series of decametric DNI maps.

  12. New Edge Localized Modes at Marginal Input Power with Dominant RF-heating and Lithium-wall Conditioning in EAST

    DEFF Research Database (Denmark)

    Wang, H.; Xu, G.; Guo, H.

    The EAST tokamak has achieved, for the rst time, the ELMy H-mode at a connement improvement factor HITER89P 1:7, with dominant RF heating and active wall conditioning by lithium evaporation and real-time injection of Li powder. During the H-mode phase, a new small-ELM regime has been observed wit......-III ELMy crash enhances the radial electric field Er and turbulence driven Reynolds stress. Furthermore, the lament-like structure of type-III ELMs has clearly been identified as multiple peaks on the ion saturation and floating potential measurements....

  13. Local structural properties and attribute characteristisc in 2-mode networks: p* models to map choices of theater events

    NARCIS (Netherlands)

    Agneessens, F.; Roose, H.

    2008-01-01

    Choices of plays made by theatergoers can be considered as a 2-mode or affiliation network. In this article we illustrate how p* models (an exponential family of distributions for random graphs) can be used to uncover patterns of choices. Based on audience research in three theater institutions in

  14. Intrinsic anomalous Hall effect and local polarizabilities

    Czech Academy of Sciences Publication Activity Database

    Středa, Pavel; Jonckheere, T.

    2010-01-01

    Roč. 82, č. 11 (2010), 113303/1-113303/4 ISSN 1098-0121 R&D Projects: GA ČR GA202/08/0551 Institutional research plan: CEZ:AV0Z10100521 Keywords : orbital polarization momentum * Berry phase correction * anomalous Hall effect Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.772, year: 2010

  15. Wide range local resistance imaging on fragile materials by conducting probe atomic force microscopy in intermittent contact mode

    International Nuclear Information System (INIS)

    Vecchiola, Aymeric; Chrétien, Pascal; Schneegans, Olivier; Mencaraglia, Denis; Houzé, Frédéric; Delprat, Sophie; Bouzehouane, Karim; Seneor, Pierre; Mattana, Richard; Tatay, Sergio; Geffroy, Bernard

    2016-01-01

    An imaging technique associating a slowly intermittent contact mode of atomic force microscopy (AFM) with a home-made multi-purpose resistance sensing device is presented. It aims at extending the widespread resistance measurements classically operated in contact mode AFM to broaden their application fields to soft materials (molecular electronics, biology) and fragile or weakly anchored nano-objects, for which nanoscale electrical characterization is highly demanded and often proves to be a challenging task in contact mode. Compared with the state of the art concerning less aggressive solutions for AFM electrical imaging, our technique brings a significantly wider range of resistance measurement (over 10 decades) without any manual switching, which is a major advantage for the characterization of materials with large on-sample resistance variations. After describing the basics of the set-up, we report on preliminary investigations focused on academic samples of self-assembled monolayers with various thicknesses as a demonstrator of the imaging capabilities of our instrument, from qualitative and semi-quantitative viewpoints. Then two application examples are presented, regarding an organic photovoltaic thin film and an array of individual vertical carbon nanotubes. Both attest the relevance of the technique for the control and optimization of technological processes.

  16. Wide range local resistance imaging on fragile materials by conducting probe atomic force microscopy in intermittent contact mode

    Energy Technology Data Exchange (ETDEWEB)

    Vecchiola, Aymeric [Laboratoire de Génie électrique et électronique de Paris (GeePs), UMR 8507 CNRS-CentraleSupélec, Paris-Sud and UPMC Universities, 11 rue Joliot-Curie, Plateau de Moulon, 91192 Gif-sur-Yvette (France); Concept Scientific Instruments, ZA de Courtaboeuf, 2 rue de la Terre de Feu, 91940 Les Ulis (France); Unité Mixte de Physique CNRS-Thales UMR 137, 1 avenue Augustin Fresnel, 91767 Palaiseau (France); Chrétien, Pascal; Schneegans, Olivier; Mencaraglia, Denis; Houzé, Frédéric, E-mail: frederic.houze@geeps.centralesupelec.fr [Laboratoire de Génie électrique et électronique de Paris (GeePs), UMR 8507 CNRS-CentraleSupélec, Paris-Sud and UPMC Universities, 11 rue Joliot-Curie, Plateau de Moulon, 91192 Gif-sur-Yvette (France); Delprat, Sophie [Unité Mixte de Physique CNRS-Thales UMR 137, 1 avenue Augustin Fresnel, 91767 Palaiseau (France); UPMC, Université Paris 06, 4 place Jussieu, 75005 Paris (France); Bouzehouane, Karim; Seneor, Pierre; Mattana, Richard [Unité Mixte de Physique CNRS-Thales UMR 137, 1 avenue Augustin Fresnel, 91767 Palaiseau (France); Tatay, Sergio [Molecular Science Institute, University of Valencia, 46980 Paterna (Spain); Geffroy, Bernard [Lab. Physique des Interfaces et Couches minces (PICM), UMR 7647 CNRS-École polytechnique, 91128 Palaiseau (France); Lab. d' Innovation en Chimie des Surfaces et Nanosciences (LICSEN), NIMBE UMR 3685 CNRS-CEA Saclay, 91191 Gif-sur-Yvette (France); and others

    2016-06-13

    An imaging technique associating a slowly intermittent contact mode of atomic force microscopy (AFM) with a home-made multi-purpose resistance sensing device is presented. It aims at extending the widespread resistance measurements classically operated in contact mode AFM to broaden their application fields to soft materials (molecular electronics, biology) and fragile or weakly anchored nano-objects, for which nanoscale electrical characterization is highly demanded and often proves to be a challenging task in contact mode. Compared with the state of the art concerning less aggressive solutions for AFM electrical imaging, our technique brings a significantly wider range of resistance measurement (over 10 decades) without any manual switching, which is a major advantage for the characterization of materials with large on-sample resistance variations. After describing the basics of the set-up, we report on preliminary investigations focused on academic samples of self-assembled monolayers with various thicknesses as a demonstrator of the imaging capabilities of our instrument, from qualitative and semi-quantitative viewpoints. Then two application examples are presented, regarding an organic photovoltaic thin film and an array of individual vertical carbon nanotubes. Both attest the relevance of the technique for the control and optimization of technological processes.

  17. Intrinsic and collective structure in the interacting boson model

    International Nuclear Information System (INIS)

    Leviatan, A.

    1987-01-01

    A general non-spherical boson basis is introduced to study the excitation modes in the interacting boson model (IBM). A prescription for construction of intrinsic states is presented. The general IBM Hamiltonian is resolved exactly into intrinsic and collective parts. The limit of large boson number is discussed analytically for spectrum and transitions. The method of analysis reveals an underlying intrinsic and collective structure closely linked with symmetry considerations. The suggested new approach seems to be adequate as a tool to obtain the physical content and normal modes in any number conserving algebraic bosonic system. copyright 1987 Academic Press, Inc

  18. Intrinsic and collective structure in the interacting boson model

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A.

    1987-11-01

    A general non-spherical boson basis is introduced to study the excitation modes in the interacting boson model (IBM). A prescription for construction of intrinsic states is presented. The general IBM Hamiltonian is resolved exactly into intrinsic and collective parts. The limit of large boson number is discussed analytically for spectrum and transitions. The method of analysis reveals an underlying intrinsic and collective structure closely linked with symmetry considerations. The suggested new approach seems to be adequate as a tool to obtain the physical content and normal modes in any number conserving algebraic bosonic system. copyright 1987 Academic Press, Inc.

  19. Physics of Penetration of Resonant Magnetic Perturbations Used for Type I Edge Localized Modes Suppression in Tokamaks

    Czech Academy of Sciences Publication Activity Database

    Bécoulet, M.; Huysmans, G.; Garbet, X.; Nardon, E.; Howell, D.; Garofalo, A.; Schaffer, M.; Evans, T.; Shaing, K.; Cole, A.; Park, J.-K.; Cahyna, Pavel

    2009-01-01

    Roč. 49, č. 8 (2009), 085011-085011 ISSN 0029-5515. [IAEA Fusion Energy Conference/22nd./. Geneva, 13.10.2008-18.10.2008] Institutional research plan: CEZ:AV0Z20430508 Keywords : resonant magnetic perturbations * ELM control * neoclassical toroidal viscosity * mode penetration Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 4.270, year: 2009 http://www.iop.org/EJ/article/0029-5515/49/8/085011/nf9_8_085011.pdf?request-id=4b61a5e0-3ab1-4c41-8ec2-468393ecbe6c

  20. Localized fluidity modes and the topology of the constant-potential-energy hypersurfaces of Lennard-Jones matter

    DEFF Research Database (Denmark)

    Cotterill, Rodney M J; Madsen, J.

    1986-01-01

    Sections of configuration space for Lennard-Jones matter were obtained by probing all the normal-mode energy profiles, following diagonalization of the dynamical matrix for a 240-particle system. For the crystal and sufficiently cold glass, these are single welled, whereas increasing numbers...... of double wells occur as the glass is warmed toward the fluid. This indicates that there might be a fundamental difference between the topologies of the constant-potential-energy hypersurfaces of crystalline and noncrystalline Lennard-Jones matter....

  1. Nonlinear local parallel acceleration of electrons through Landau trapping by oblique whistler mode waves in the outer radiation belt

    OpenAIRE

    Agapitov, O. V.; Artemyev, A. V.; Mourenas, D.; Mozer, F. S.; Krasnoselskikh, V.

    2015-01-01

    International audience; Simultaneous observations of electron velocity distributions and chorus waves by the Van Allen Probe B are analyzed to identify long-lasting (more than 6 h) signatures of electron Landau resonant interactions with oblique chorus waves in the outer radiation belt. Such Landau resonant interactions result in the trapping of ˜1-10 keV electrons and their acceleration up to 100-300 keV. This kind of process becomes important for oblique whistler mode waves having a signifi...

  2. Near IR overtone spectral investigations of cyclohexanol using local mode model--evidence for variation of anharmonicity with concentration due to hydrogen bonding.

    Science.gov (United States)

    John, Usha; Nair, K P R

    2005-09-01

    The near infrared vibrational overtone absorption spectrum of liquid phase cyclohexanol in carbon tetrachloride in different concentrations are examined in the region Deltav=2, 3 and 4. The free and bonded OH local mode mechanical frequency values and anharmonicity values obtained from fitting the overtones are analysed. The observation supports the conclusions drawn from earlier experimental studies on anharmonicity variation of OH-stretching vibrations of alcohols due to intermolecular hydrogen bonding. Our observation is also in agreement with the ab initio calculations on water dimer and trimer. Mechanical anharmonicity of bonded OH-stretching bands tends to increase as a consequence of strong hydrogen bonding at higher concentrations.

  3. Semi-analytical quasi-normal mode theory for the local density of states in coupled photonic crystal cavity-waveguide structures

    DEFF Research Database (Denmark)

    de Lasson, Jakob Rosenkrantz; Kristensen, Philip Trøst; Mørk, Jesper

    2015-01-01

    We present and validate a semi-analytical quasi-normal mode (QNM) theory for the local density of states (LDOS) in coupled photonic crystal (PhC) cavity-waveguide structures. By means of an expansion of the Green's function on one or a few QNMs, a closed-form expression for the LDOS is obtained......-trivial spectrum with a peak and a dip is found, which is reproduced only when including both the two relevant QNMs in the theory. In both cases, we find relative errors below 1% in the bandwidth of interest....

  4. A 250-Mbit/s ring local computer network using 1.3-microns single-mode optical fibers

    Science.gov (United States)

    Eng, S. T.; Tell, R.; Andersson, T.; Eng, B.

    1985-01-01

    A 250-Mbit/s three-station fiber-optic ring local computer network was built and successfully demonstrated. A conventional token protocol was employed for bus arbitration to maximize the bus efficiency under high loading conditions, and a non-return-to-zero (NRS) data encoding format was selected for simplicity and maximum utilization of the ECL-circuit bandwidth.

  5. Intrinsic contractures of the hand.

    Science.gov (United States)

    Paksima, Nader; Besh, Basil R

    2012-02-01

    Contractures of the intrinsic muscles of the fingers disrupt the delicate and complex balance of intrinsic and extrinsic muscles, which allows the hand to be so versatile and functional. The loss of muscle function primarily affects the interphalangeal joints but also may affect etacarpophalangeal joints. The resulting clinical picture is often termed, intrinsic contracture or intrinsic-plus hand. Disruption of the balance between intrinsic and extrinsic muscles has many causes and may be secondary to changes within the intrinsic musculature or the tendon unit. This article reviews diagnosis, etiology, and treatment algorithms in the management of intrinsic contractures of the fingers. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Global two-fluid turbulence simulations of L-H transitions and edge localized mode dynamics in the COMPASS-D tokamak

    Science.gov (United States)

    Thyagaraja, A.; Valovič, M.; Knight, P. J.

    2010-04-01

    It is shown that the transition from L-mode to H-mode regimes in tokamaks can be reproduced using a two-fluid, fully electromagnetic, plasma model when a suitable particle sink is added at the edge. Such a model is implemented in the CUTIE code [A. Thyagaraja et al., Eur. J. Mech. B/Fluids 23, 475 (2004)] and is illustrated on plasma parameters that mimic those in the COMPASS-D tokamak with electron cyclotron resonance heating [Fielding et al., Plasma Phys. Contr. Fusion 42, A191 (2000)]. In particular, it is shown that holding the heating power, current, and magnetic field constant and increasing the fuelling rate to raise the plasma density leads spontaneously to the formation of an edge transport barrier (ETB) which occurs going from low to higher density experimentally. In the following quiescent period in which the stored energy of the plasma rises linearly with time, a dynamical transition occurs in the simulation with the appearance of features resembling strong edge localized modes. The simulation qualitatively reproduces many features observed in the experiment. Its relative robustness suggests that some, at least of the observed characteristics of ETBs and L-H transitions, can be captured in the global electromagnetic turbulence model.

  7. Predicting Intrinsic Motivation

    Science.gov (United States)

    Martens, Rob; Kirschner, Paul A.

    2004-01-01

    Intrinsic motivation can be predicted from participants' perceptions of the social environment and the task environment (Ryan & Deci, 2000)in terms of control, relatedness and competence. To determine the degree of independence of these factors 251 students in higher vocational education (physiotherapy and hotel management) indicated the…

  8. Ordinary mode reflectometry. Modification of the scattering and cut-off responses due to the shape of localized density fluctuations

    International Nuclear Information System (INIS)

    Fanack, C.; Boucher, I.; Heuraux, S.; Leclert, G.; Clairet, F.; Zou, X.L.

    1996-01-01

    Ordinary wave reflectometry in a plasma containing a localized density perturbation is studied with a 1-D model. The phase response is studied as a function of the wavenumber and position of the perturbation. It is shown that it strongly depends upon the perturbation shape and size. For a small perturbation wavenumber, the response is due to the oscillation of the cut-off layer. For larger wavenumbers, two regimes are found: for a broad perturbation, the phase response is an image of the perturbation itself; for a narrow perturbation, it is rather an image of the Fourier transform. For tokamak plasmas it turns out that, for the fluctuation spectra usually observed, the phase response comes primarily from those fluctuations that are localized at the cut-off. Results of a 2-D numerical model show that geometry effects are negligible for the scattering by radial fluctuations. (author)

  9. Localized Scrape-Off Layer density modifications by Ion Cyclotron near fields in JET and ASDEX-Upgrade L-mode plasmas

    Science.gov (United States)

    Colas, L.; Jacquet, Ph.; Van Eester, D.; Bobkov, V.; Brix, M.; Meneses, L.; Tamain, P.; Marsen, S.; Silva, C.; Carralero, D.; Kočan, M.; Müller, H.-W.; Crombé, K.; Křivska, A.; Goniche, M.; Lerche, E.; Rimini, F. G.; JET-EFDA Contributors

    2015-08-01

    Combining Lithium beam emission spectroscopy and edge reflectometry, localized Scrape-Off Layer (SOL) density modifications by Ion Cyclotron Range of Frequencies (ICRF) near fields were characterized in JET L-mode plasmas. When using the ICRF wave launchers connected magnetically to the Li-beam chord, the density decreased more steeply 2-3 cm outside the last closed flux surface (mapped onto the outer mid-plane) and its value at the outer limiter radial position was half the ohmic value. The depletion depends on the ICRF power and on the phasing between adjacent radiating straps. Convection due to ponderomotive effects and/or E × B0 drifts is suspected: during ICRF-heated H-mode discharges in 2013, DC potentials up to 70 V were measured locally in the outer SOL by a floating reciprocating probe, located toroidally several metres from the active antennas. These observations are compared with probe measurements on ASDEX-Upgrade. Their implications for wave coupling, heat loads and impurity production are discussed.

  10. Effects of gender, digit ratio, and menstrual cycle on intrinsic brain functional connectivity: A whole-brain, voxel-wise exploratory study using simultaneous local and global functional connectivity mapping.

    Science.gov (United States)

    Donishi, Tomohiro; Terada, Masaki; Kaneoke, Yoshiki

    2018-01-01

    Gender and sex hormones influence brain function, but their effects on functional network organization within the brain are not yet understood. We investigated the influence of gender, prenatal sex hormones (estimated by the 2D:4D digit ratio), and the menstrual cycle on the intrinsic functional network organization of the brain (as measured by 3T resting-state functional MRI (rs-fMRI)) using right-handed, age-matched university students (100 males and 100 females). The mean (± SD ) age was 20.9 ± 1.5 (range: 18-24) years and 20.8 ± 1.3 (range: 18-24) years for males and females, respectively. Using two parameters derived from the normalized alpha centrality analysis (one for local and another for global connectivity strength), we created mean functional connectivity strength maps. There was a significant difference between the male mean map and female mean map in the distributions of network properties in almost all cortical regions and the basal ganglia but not in the medial parietal, limbic, and temporal regions and the thalamus. A comparison between the mean map for the low 2D:4D digit ratio group (indicative of high exposure to testosterone during the prenatal period) and that for the high 2D:4D digit ratio group revealed a significant difference in the network properties of the medial parietal region for males and in the temporal region for females. The menstrual cycle affected network organization in the brain, which varied with the 2D:4D digit ratio. Most of these findings were reproduced with our other datasets created with different preprocessing steps. The results suggest that differences in gender, prenatal sex hormone exposure, and the menstrual cycle are useful for understanding the normal brain and investigating the mechanisms underlying the variable prevalence and symptoms of neurological and psychiatric diseases.

  11. Simple intrinsic defects in InAs :

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, Peter Andrew

    2013-03-01

    This Report presents numerical tables summarizing properties of intrinsic defects in indium arsenide, InAs, as computed by density functional theory using semi-local density functionals, intended for use as reference tables for a defect physics package in device models.

  12. A rotational integral formula for intrinsic volumes

    DEFF Research Database (Denmark)

    Jensen, Eva Bjørn Vedel; Rataj, J.

    2008-01-01

    A rotational version of the famous Crofton formula is derived. The motivation for deriving the formula comes from local stereology, a new branch of stereology based on sections through fixed reference points. The formula shows how rotational averages of intrinsic volumes measured on sections...

  13. Suppression of large edge localized modes with a stochastic magnetic boundary in high confinement DIII-D plasmas

    International Nuclear Information System (INIS)

    Evans, T.E.; Moyer, R.A.; Watkins, J.G.

    2005-01-01

    Large sub-millisecond heat pulses due to Type-I ELMs have been eliminated reproducibly in DIII.D for periods approaching 7 energy confinement times with small dc currents driven in a simple magnetic perturbation coil. The current required to eliminate all but a few isolated Type-I ELM impulses during a coil pulse is less than 0.4% of plasma current. Based on vacuum magnetic field line modeling, the perturbation fields resonate strongly with plasma flux surfaces across most of the pedestal region (0.9 ≤ Ψ N ≤ 1.0) when q 95 = 3.7±0.2 creating small remnant magnetic islands surrounded by weakly stochastic field lines. The stored energy, β N , H-mode quality factor and global energy confinement time are unaltered. Although some isolated ELM-like events typically occur, long periods free of large Type-I ELMs (Δt > 4-6 τ E ) have been reproduced numerous times, on multiple experimental run days including cases matching the ITER scenario 2 flux surface shape. Since large Type-I ELM impulses represent a severe constraint on the survivability of the divertor target plates in future fusion devices such as ITER, a proven method of eliminating these impulses is critical for the development of tokamak reactors. Results presented in this paper indicate that non-axisymmetric edge magnetic perturbations could be a promising option for controlling ELMs in future tokamaks such as ITER. (author)

  14. Mode of action of cupping--local metabolism and pain thresholds in neck pain patients and healthy subjects.

    Science.gov (United States)

    Emerich, M; Braeunig, M; Clement, H W; Lüdtke, R; Huber, R

    2014-02-01

    Cupping worldwide has been part of traditional medicine systems and is in the western world used as CAM therapy mainly for treating pain syndromes. The mode of action is up to now unclear. In order to investigate its mechanism we measured in parallel metabolic changes in the tissue under the cupping glass and pressure pain thresholds. In 12 volunteers (6 healthy subjects and 6 patients with chronic neck pain) a microdialysis system was implanted subcutaneously on both sides (left and right) above the trapezius muscle. After baseline measures cupping was performed at one randomly selected side (left or right), the other side served as control. Every 20 min during baseline measures and for 280 min after cupping, microdialysis probes for detection of lactate, pyruvate, glucose and glycerin were taken. In addition, pain thresholds were measured before and after cupping with algometry. Cupping resulted in a strong increase of lactate (beginning 160 min after cupping until the end of the measurements) and the lactate/pyruvate ratio, indicating an anaerobe metabolism in the surrounding tissue. Baseline pain thresholds were non-significantly lower in neck pain patients compared to healthy controls and slightly increased immediately after cupping (ppain patients). After 280 min no more significant changes of pain thresholds were detected. Cupping induces >280 min lasting anaerobe metabolism in the subcutaneous tissue and increases immediate pressure pain thresholds in some areas. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Intrinsic and Extrinsic Motivation

    OpenAIRE

    Roland Bénabou; Jean Tirole

    2003-01-01

    A central tenet of economics is that individuals respond to incentives. For psychologists and sociologists, in contrast, rewards and punishments are often counterproductive, because they undermine "intrinsic motivation". We reconcile these two views, showing how performance incentives offered by an informed principal (manager, teacher, parent) can adversely impact an agent's (worker, child) perception of the task, or of his own abilities. Incentives are then only weak reinforcers in the short...

  16. A dual-mode hemispherical sparse array for 3D passive acoustic mapping and skull localization within a clinical MRI guided focused ultrasound device

    Science.gov (United States)

    Crake, Calum; Brinker, Spencer T.; Coviello, Christian M.; Livingstone, Margaret S.; McDannold, Nathan J.

    2018-03-01

    Previous work has demonstrated that passive acoustic imaging may be used alongside MRI for monitoring of focused ultrasound therapy. However, past implementations have generally made use of either linear arrays originally designed for diagnostic imaging or custom narrowband arrays specific to in-house therapeutic transducer designs, neither of which is fully compatible with clinical MR-guided focused ultrasound (MRgFUS) devices. Here we have designed an array which is suitable for use within an FDA-approved MR-guided transcranial focused ultrasound device, within the bore of a 3 Tesla clinical MRI scanner. The array is constructed from 5  ×  0.4 mm piezoceramic disc elements arranged in pseudorandom fashion on a low-profile laser-cut acrylic frame designed to fit between the therapeutic elements of a 230 kHz InSightec ExAblate 4000 transducer. By exploiting thickness and radial resonance modes of the piezo discs the array is capable of both B-mode imaging at 5 MHz for skull localization, as well as passive reception at the second harmonic of the therapy array for detection of cavitation and 3D passive acoustic imaging. In active mode, the array was able to perform B-mode imaging of a human skull, showing the outer skull surface with good qualitative agreement with MR imaging. Extension to 3D showed the array was able to locate the skull within  ±2 mm/2° of reference points derived from MRI, which could potentially allow registration of a patient to the therapy system without the expense of real-time MRI. In passive mode, the array was able to resolve a point source in 3D within a  ±10 mm region about each axis from the focus, detect cavitation (SNR ~ 12 dB) at burst lengths from 10 cycles to continuous wave, and produce 3D acoustic maps in a flow phantom. Finally, the array was used to detect and map cavitation associated with microbubble activity in the brain in nonhuman primates.

  17. Relativistic electron dynamics produced by azimuthally localized poloidal mode ULF waves: Boomerang-shaped pitch angle evolutions

    Science.gov (United States)

    Hao, Y. X.; Zong, Q.-G.; Zhou, X.-Z.; Rankin, R.; Chen, X. R.; Liu, Y.; Fu, S. Y.; Spence, H. E.; Blake, J. B.; Reeves, G. D.

    2017-08-01

    We present an analysis of "boomerang-shaped" pitch angle evolutions of outer radiation belt relativistic electrons observed by the Van Allen Probes after the passage of an interplanetary shock on 7 June 2014. The flux at different pitch angles is modulated by Pc5 waves, with equatorially mirroring electrons reaching the satellite first. For 90° pitch angle electrons, the phase change of the flux modulations across energy exceeds 180° and increasingly tilts with time. Using estimates of the arrival time of particles of different pitch angles at the spacecraft location, a scenario is investigated in which shock-induced ULF waves interact with electrons through the drift resonance mechanism in a localized region westward of the spacecraft. Numerical calculations on particle energy gain with the modified ULF wavefield reproduce the observed boomerang stripes and modulations in the electron energy spectrogram. The study of boomerang stripes and their relationship to drift resonance taking place at a location different from the observation point adds new understanding of the processes controlling the dynamics of the outer radiation belt.

  18. Intrinsic and extrinsic mortality reunited

    DEFF Research Database (Denmark)

    Koopman, Jacob J E; Wensink, Maarten J; Rozing, Maarten P

    2015-01-01

    Intrinsic and extrinsic mortality are often separated in order to understand and measure aging. Intrinsic mortality is assumed to be a result of aging and to increase over age, whereas extrinsic mortality is assumed to be a result of environmental hazards and be constant over age. However......, allegedly intrinsic and extrinsic mortality have an exponentially increasing age pattern in common. Theories of aging assert that a combination of intrinsic and extrinsic stressors underlies the increasing risk of death. Epidemiological and biological data support that the control of intrinsic as well...... as extrinsic stressors can alleviate the aging process. We argue that aging and death can be better explained by the interaction of intrinsic and extrinsic stressors than by classifying mortality itself as being either intrinsic or extrinsic. Recognition of the tight interaction between intrinsic and extrinsic...

  19. Cell intrinsic control of axon regeneration

    Science.gov (United States)

    Mar, Fernando M; Bonni, Azad; Sousa, Mónica M

    2014-01-01

    Although neurons execute a cell intrinsic program of axonal growth during development, following the establishment of connections, the developmental growth capacity declines. Besides environmental challenges, this switch largely accounts for the failure of adult central nervous system (CNS) axons to regenerate. Here, we discuss the cell intrinsic control of axon regeneration, including not only the regulation of transcriptional and epigenetic mechanisms, but also the modulation of local protein translation, retrograde and anterograde axonal transport, and microtubule dynamics. We further explore the causes underlying the failure of CNS neurons to mount a vigorous regenerative response, and the paradigms demonstrating the activation of cell intrinsic axon growth programs. Finally, we present potential mechanisms to support axon regeneration, as these may represent future therapeutic approaches to promote recovery following CNS injury and disease. PMID:24531721

  20. A discrete model of the development and relaxation of a local microbreakdown in silicon avalanche photodiodes operating in the Geiger mode

    International Nuclear Information System (INIS)

    Vanyushin, I. V.; Gergel, V. A.; Gontar', V. M.; Zimoglyad, V. A.; Tishin, Yu. I.; Kholodnov, V. A.; Shcheleva, I. M.

    2007-01-01

    A new discrete theoretical model of the development and relaxation of a local microbreakdown in silicon avalanche photodiodes operating in the Geiger mode is developed. It is shown that the spreading resistance in the substrate profoundly affects both the amplitude of a single-photon electrical pulse and the possibility of attaining the steady-state form of the avalanche breakdown excluding the Geiger mode of the photodiode's operation. The model is employed to interpret the experimental data obtained using test single-photon cells of avalanche photodiodes fabricated on the basis of the 0.25-μm silicon technology with the use of deep implantation to form the region of avalanche multiplication for the charge carriers. Excellent functional properties of the studied type of the single-photon (Geiger) cell are noted. A typical amplitude characteristic of the cell for optical radiation with the wavelength λ = 0.56 μm in the irradiance range of 10 -3 -10 2 lx is presented; this characteristic indicates that the quantum efficiency of photoconversion is extremely high

  1. Modes of Governing and Policy of Local and Regional Governments Supporting Local Low-Carbon Energy Initiatives; Exploring the Cases of the Dutch Regions of Overijssel and Fryslân

    Directory of Open Access Journals (Sweden)

    Beau Warbroek

    2017-01-01

    Full Text Available Recent scholarly attention shows increasing involvement of local low-carbon energy initiatives (LLCEIs in governance and policy, in particular in relation to innovations regarding low-carbon energy and energy efficiency. The future perspective of active citizenship in the production of locally generated low-carbon energy is largely dependent on the existing institutional and policy frameworks and settings. Subnational governments, in particular, can have a prominent role in this process by engaging in institutional adaptation and policy innovation. The central research question of this paper is: In what ways do local and regional governments innovate in governing to respond to the emergence of LLCEIs? The research question is answered by comparing two case studies: the Dutch regions of Overijssel and Fryslân. We have conceptualized a meta-governing approach of experimentation, characterizing the innovations in governing that emerge when governments respond to the emergence of LLCEIs. We specifically focus on two capacities that subnational governments can use to enhance their governing capacity vis-à-vis LLCEIs and which substantiate the experimental meta-governance mode: institutional adaptation and policy innovation. We then formulated hypotheses that specify the expected policy innovations and institutional adaptations employed vis-à-vis LLCEIs. Data collection involved in-depth interviews and use of secondary data. The results show that a balancing process of authoritative and enabling modes of governing particularly characterized the type of policy innovations that were developed and the institutional adaptations that took place. Both provinces govern LLCEIs at arm’s length and issue significant capacity-building strategies that vary in terms of their conditions. Municipalities, however, incline towards impromptu and opportunistic responses, some of them having lasting effects by patching up existing institutional settings, others

  2. MO-DE-207A-11: Sparse-View CT Reconstruction Via a Novel Non-Local Means Method

    International Nuclear Information System (INIS)

    Chen, Z; Qi, H; Wu, S; Xu, Y; Zhou, L

    2016-01-01

    Purpose: Sparse-view computed tomography (CT) reconstruction is an effective strategy to reduce the radiation dose delivered to patients. Due to its insufficiency of measurements, traditional non-local means (NLM) based reconstruction methods often lead to over-smoothness in image edges. To address this problem, an adaptive NLM reconstruction method based on rotational invariance (RIANLM) is proposed. Methods: The method consists of four steps: 1) Initializing parameters; 2) Algebraic reconstruction technique (ART) reconstruction using raw projection data; 3) Positivity constraint of the image reconstructed by ART; 4) Update reconstructed image by using RIANLM filtering. In RIANLM, a novel similarity metric that is rotational invariance is proposed and used to calculate the distance between two patches. In this way, any patch with similar structure but different orientation to the reference patch would win a relatively large weight to avoid over-smoothed image. Moreover, the parameter h in RIANLM which controls the decay of the weights is adaptive to avoid over-smoothness, while it in NLM is not adaptive during the whole reconstruction process. The proposed method is named as ART-RIANLM and validated on Shepp-Logan phantom and clinical projection data. Results: In our experiments, the searching neighborhood size is set to 15 by 15 and the similarity window is set to 3 by 3. For the simulated case with a resolution of 256 by 256 Shepp-Logan phantom, the ART-RIANLM produces higher SNR (35.38dB<24.00dB) and lower MAE (0.0006<0.0023) reconstructed image than ART-NLM. The visual inspection demonstrated that the proposed method could suppress artifacts or noises more effectively and preserve image edges better. Similar results were found for clinical data case. Conclusion: A novel ART-RIANLM method for sparse-view CT reconstruction is presented with superior image. Compared to the conventional ART-NLM method, the SNR and MAE from ART-RIANLM increases 47% and decreases 74

  3. Generalised ballooning theory of two-dimensional tokamak modes

    Science.gov (United States)

    Abdoul, P. A.; Dickinson, D.; Roach, C. M.; Wilson, H. R.

    2018-02-01

    In this work, using solutions from a local gyrokinetic flux-tube code combined with higher order ballooning theory, a new analytical approach is developed to reconstruct the global linear mode structure with associated global mode frequency. In addition to the isolated mode (IM), which usually peaks on the outboard mid-plane, the higher order ballooning theory has also captured other types of less unstable global modes: (a) the weakly asymmetric ballooning theory (WABT) predicts a mixed mode (MM) that undergoes a small poloidal shift away from the outboard mid-plane, (b) a relatively more stable general mode (GM) balloons on the top (or bottom) of the tokamak plasma. In this paper, an analytic approach is developed to combine these disconnected analytical limits into a single generalised ballooning theory. This is used to investigate how an IM behaves under the effect of sheared toroidal flow. For small values of flow an IM initially converts into a MM where the results of WABT are recaptured, and eventually, as the flow increases, the mode asymptotically becomes a GM on the top (or bottom) of the plasma. This may be an ingredient in models for understanding why in some experimental scenarios, instead of large edge localised modes (ELMs), small ELMs are observed. Finally, our theory can have other important consequences, especially for calculations involving Reynolds stress driven intrinsic rotation through the radial asymmetry in the global mode structures. Understanding the intrinsic rotation is significant because external torque in a plasma the size of ITER is expected to be relatively low.

  4. Intrinsic point defects in aluminum antimonide

    OpenAIRE

    Åberg, Daniel; Erhart, Paul; Williamson, Andrew J.; Lordi, Vincenzo

    2010-01-01

    Calculations within density functional theory on the basis of the local density approximation are carried out to study the properties of intrinsic point defects in aluminum antimonide. Special care is taken to address finite-size effects, band gap error, and symmetry reduction in the defect structures. The correction of the band gap is based on a set of GW calculations. The most important defects are identified to be the aluminum interstitial $Al_{i,Al}^{1+}$, the antimony antisites $Sb_{Al}^...

  5. Intrinsic Chevrolets at the SSC

    International Nuclear Information System (INIS)

    Brodsky, S.J.; Collins, J.C.; Ellis, S.D.; Gunion, J.F.; Mueller, A.H.

    1984-01-01

    The possibility of the production at high energy of heavy quarks, supersymmetric particles and other large mass colored systems via the intrinsic twist-six components in the proton wave function is discussed. While the existing data do not rule out the possible relevance of intrinsic charm production at present energies, the extrapolation of such intrinsic contributions to very high masses and energies suggests that they will not play an important role at the SSC

  6. New approach in two-dimensional fluid modeling of edge plasma transport with high intermittency due to blobs and edge localized modes

    International Nuclear Information System (INIS)

    Pigarov, A. Yu.; Krasheninnikov, S. I.; Rognlien, T. D.

    2011-01-01

    A new approach is proposed to simulate intermittent, non-diffusive plasma transport (via blobs and filaments of edge localized modes (ELMs)) observed in the tokamak edge region within the framework of two-dimensional transport codes. This approach combines the inherently three-dimensional filamentary structures associated with an ensemble of blobs into a macro-blob in the two-dimensional poloidal cross-section and advects the macro-blob ballistically across the magnetic field, B. Intermittent transport is represented as a sequence of macro-blobs appropriately seeded in the edge plasma according to experimental statistics. In this case, the code is capable of reproducing both the long-scale temporal evolution of the background plasma and the fast spatiotemporal dynamics of blobs. We report the results from a two-dimensional edge plasma code modeling of a single macro-blob dynamics, and its interaction with initially stationary background plasma as well as with material surfaces. The mechanisms of edge plasma particle and energy losses from macro-blobs are analyzed. The effects of macro-blob sizes and advection velocity on edge plasma profiles are studied. The macro-blob impact on power loading and sputtering rates on the chamber wall and on inner and outer divertor plates is discussed. Temporal evolution of particle inventory of the edge plasma perturbed by macro-blobs is analyzed. Application of macro-blobs to ELM modeling is highlighted.

  7. Reduced-order computational model in nonlinear structural dynamics for structures having numerous local elastic modes in the low-frequency range. Application to fuel assemblies

    Energy Technology Data Exchange (ETDEWEB)

    Batou, A., E-mail: anas.batou@univ-paris-est.fr [Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallee (France); Soize, C., E-mail: christian.soize@univ-paris-est.fr [Université Paris-Est, Laboratoire Modélisation et Simulation Multi Echelle, MSME UMR 8208 CNRS, 5 bd Descartes, 77454 Marne-la-Vallee (France); Brie, N., E-mail: nicolas.brie@edf.fr [EDF R and D, Département AMA, 1 avenue du général De Gaulle, 92140 Clamart (France)

    2013-09-15

    Highlights: • A ROM of a nonlinear dynamical structure is built with a global displacements basis. • The reduced order model of fuel assemblies is accurate and of very small size. • The shocks between grids of a row of seven fuel assemblies are computed. -- Abstract: We are interested in the construction of a reduced-order computational model for nonlinear complex dynamical structures which are characterized by the presence of numerous local elastic modes in the low-frequency band. This high modal density makes the use of the classical modal analysis method not suitable. Therefore the reduced-order computational model is constructed using a basis of a space of global displacements, which is constructed a priori and which allows the nonlinear dynamical response of the structure observed on the stiff part to be predicted with a good accuracy. The methodology is applied to a complex industrial structure which is made up of a row of seven fuel assemblies with possibility of collisions between grids and which is submitted to a seismic loading.

  8. Intrinsically dynamic population models

    Directory of Open Access Journals (Sweden)

    Robert Schoen

    2005-03-01

    Full Text Available Intrinsically dynamic models (IDMs depict populations whose cumulative growth rate over a number of intervals equals the product of the long term growth rates (that is the dominant roots or dominant eigenvalues associated with each of those intervals. Here the focus is on the birth trajectory produced by a sequence of population projection (Leslie matrices. The elements of a Leslie matrix are represented as straightforward functions of the roots of the matrix, and new relationships are presented linking the roots of a matrix to its Net Reproduction Rate and stable mean age of childbearing. Incorporating mortality changes in the rates of reproduction yields an IDM when the subordinate roots are held constant over time. In IDMs, the birth trajectory generated by any specified sequence of Leslie matrices can be found analytically. In the Leslie model with 15 year age groups, the constant subordinate root assumption leads to reasonable changes in the age pattern of fertility, and equations (27 and (30 provide the population size and structure that result from changing levels of net reproduction. IDMs generalize the fixed rate stable population model. They can characterize any observed population, and can provide new insights into dynamic demographic behavior, including the momentum associated with gradual or irregular paths to zero growth.

  9. Electrophysiological signatures of atypical intrinsic brain connectivity networks in autism

    Science.gov (United States)

    Shou, Guofa; Mosconi, Matthew W.; Wang, Jun; Ethridge, Lauren E.; Sweeney, John A.; Ding, Lei

    2017-08-01

    Objective. Abnormal local and long-range brain connectivity have been widely reported in autism spectrum disorder (ASD), yet the nature of these abnormalities and their functional relevance at distinct cortical rhythms remains unknown. Investigations of intrinsic connectivity networks (ICNs) and their coherence across whole brain networks hold promise for determining whether patterns of functional connectivity abnormalities vary across frequencies and networks in ASD. In the present study, we aimed to probe atypical intrinsic brain connectivity networks in ASD from resting-state electroencephalography (EEG) data via characterizing the whole brain network. Approach. Connectivity within individual ICNs (measured by spectral power) and between ICNs (measured by coherence) were examined at four canonical frequency bands via a time-frequency independent component analysis on high-density EEG, which were recorded from 20 ASD and 20 typical developing (TD) subjects during an eyes-closed resting state. Main results. Among twelve identified electrophysiological ICNs, individuals with ASD showed hyper-connectivity in individual ICNs and hypo-connectivity between ICNs. Functional connectivity alterations in ASD were more severe in the frontal lobe and the default mode network (DMN) and at low frequency bands. These functional connectivity measures also showed abnormal age-related associations in ICNs related to frontal, temporal and motor regions in ASD. Significance. Our findings suggest that ASD is characterized by the opposite directions of abnormalities (i.e. hypo- and hyper-connectivity) in the hierarchical structure of the whole brain network, with more impairments in the frontal lobe and the DMN at low frequency bands, which are critical for top-down control of sensory systems, as well as for both cognition and social skills.

  10. The brain's default mode network.

    Science.gov (United States)

    Raichle, Marcus E

    2015-07-08

    The brain's default mode network consists of discrete, bilateral and symmetrical cortical areas, in the medial and lateral parietal, medial prefrontal, and medial and lateral temporal cortices of the human, nonhuman primate, cat, and rodent brains. Its discovery was an unexpected consequence of brain-imaging studies first performed with positron emission tomography in which various novel, attention-demanding, and non-self-referential tasks were compared with quiet repose either with eyes closed or with simple visual fixation. The default mode network consistently decreases its activity when compared with activity during these relaxed nontask states. The discovery of the default mode network reignited a longstanding interest in the significance of the brain's ongoing or intrinsic activity. Presently, studies of the brain's intrinsic activity, popularly referred to as resting-state studies, have come to play a major role in studies of the human brain in health and disease. The brain's default mode network plays a central role in this work.

  11. Streaming tearing mode

    Science.gov (United States)

    Shigeta, M.; Sato, T.; Dasgupta, B.

    1985-01-01

    The magnetohydrodynamic stability of streaming tearing mode is investigated numerically. A bulk plasma flow parallel to the antiparallel magnetic field lines and localized in the neutral sheet excites a streaming tearing mode more strongly than the usual tearing mode, particularly for the wavelength of the order of the neutral sheet width (or smaller), which is stable for the usual tearing mode. Interestingly, examination of the eigenfunctions of the velocity perturbation and the magnetic field perturbation indicates that the streaming tearing mode carries more energy in terms of the kinetic energy rather than the magnetic energy. This suggests that the streaming tearing mode instability can be a more feasible mechanism of plasma acceleration than the usual tearing mode instability.

  12. Intrinsic spatial resolution limitations due to differences between positron emission position and annihilation detection localization; Limitacoes da resolucao espacial intrinseca devido as diferencas entre a posicao da emissao do positron e a deteccao da localizacao de aniquilacao

    Energy Technology Data Exchange (ETDEWEB)

    Perez, Pedro; Malano, Francisco; Valente, Mauro, E-mail: valente@famaf.unc.edu.ar [Universidad Nacional de Cordoba, Cordoba (Argentina). Fac. de Matematica, Astronomia y Fisica (FaMAF)

    2012-07-01

    Since its successful implementation for clinical diagnostic, positron emission tomography (PET) represents the most promising medical imaging technique. The recent major growth of PET imaging is mainly due to its ability to trace the biologic pathways of different compounds in the patient's body, assuming the patient can be labeled with some PET isotope. Regardless of the type of isotope, the PET imaging method is based on the detection of two 511-keV gamma photons being emitted in opposite directions, with almost 180 deg between them, as a consequence of electron-positron annihilation. Therefore, this imaging method is intrinsically limited by random uncertainties in spatial resolutions, related with differences between the actual position of positron emission and the location of the detected annihilation. This study presents an approach with the Monte Carlo method to analyze the influence of this effect on different isotopes of potential implementation in PET. (author)

  13. Prediction of biological motion perception performance from intrinsic brain network regional efficiency

    Directory of Open Access Journals (Sweden)

    Zengjian Wang

    2016-11-01

    Full Text Available Biological motion perception (BMP is a vivid perception of the moving form of a human figure from a few light points on the joints of the body. BMP is commonplace and important, but there is great inter-individual variability in this ability. This study used multiple regression model analysis to explore the association between the BMP performance and intrinsic brain activity, in order to investigate the neural substrates underlying inter-individual variability of BMP performance. The resting-state functional magnetic resonance imaging (rs-fMRI and BMP performance data were collected from 24 healthy participants. For each participant, the intrinsic brain network was constructed, and a graph-based network efficiency metric was measured. Then, a multiple linear regression model was used to explore the association between network regional efficiency and BMP performance. We found that the local and global network efficiency of many regions was significantly correlated with the BMP performance. Further analysis showed that the local efficiency rather than global efficiency could be used to explain most of the BMP inter-individual variability, and the regions involved were predominately located at the Default Mode Network (DMN. Additionally, the discrimination analysis showed that the local efficiency over regions including thalamus could be used to classify BMP performance across participants. Notably, the association pattern between the network nodal efficiency and the BMP was different from the association pattern that of the static directional/gender information perception. Overall, these findings showed that intrinsic brain network efficiency may be considered as a neural factor that explains BMP inter-individual variability. Keywords: Biological motion; Resting-state network; Network efficiency; Multiple linear regression model; Brain-behavior analysis

  14. Prediction of Biological Motion Perception Performance from Intrinsic Brain Network Regional Efficiency

    Science.gov (United States)

    Wang, Zengjian; Zhang, Delong; Liang, Bishan; Chang, Song; Pan, Jinghua; Huang, Ruiwang; Liu, Ming

    2016-01-01

    Biological motion perception (BMP) refers to the ability to perceive the moving form of a human figure from a limited amount of stimuli, such as from a few point lights located on the joints of a moving body. BMP is commonplace and important, but there is great inter-individual variability in this ability. This study used multiple regression model analysis to explore the association between BMP performance and intrinsic brain activity, in order to investigate the neural substrates underlying inter-individual variability of BMP performance. The resting-state functional magnetic resonance imaging (rs-fMRI) and BMP performance data were collected from 24 healthy participants, for whom intrinsic brain networks were constructed, and a graph-based network efficiency metric was measured. Then, a multiple linear regression model was used to explore the association between network regional efficiency and BMP performance. We found that the local and global network efficiency of many regions was significantly correlated with BMP performance. Further analysis showed that the local efficiency rather than global efficiency could be used to explain most of the BMP inter-individual variability, and the regions involved were predominately located in the Default Mode Network (DMN). Additionally, discrimination analysis showed that the local efficiency of certain regions such as the thalamus could be used to classify BMP performance across participants. Notably, the association pattern between network nodal efficiency and BMP was different from the association pattern of static directional/gender information perception. Overall, these findings show that intrinsic brain network efficiency may be considered a neural factor that explains BMP inter-individual variability. PMID:27853427

  15. Dual-Mode Combustor

    Science.gov (United States)

    Trefny, Charles J (Inventor); Dippold, Vance F (Inventor)

    2013-01-01

    A new dual-mode ramjet combustor used for operation over a wide flight Mach number range is described. Subsonic combustion mode is usable to lower flight Mach numbers than current dual-mode scramjets. High speed mode is characterized by supersonic combustion in a free-jet that traverses the subsonic combustion chamber to a variable nozzle throat. Although a variable combustor exit aperture is required, the need for fuel staging to accommodate the combustion process is eliminated. Local heating from shock-boundary-layer interactions on combustor walls is also eliminated.

  16. Intrinsically Passive Handling and Grasping

    NARCIS (Netherlands)

    Stramigioli, Stefano; Scherpen, Jacquelien M.A.; Khodabandehloo, Koorosh

    2000-01-01

    The paper presents a control philosophy called Intrinsically Passive Control, which has the feature to properly behave during interaction with any passive objects. The controlled robot will never become unstable due to the physical structure of the controller.

  17. Binding mechanisms of intrinsically disordered proteins: theory, simulation, and experiment

    Directory of Open Access Journals (Sweden)

    Luca Mollica

    2016-09-01

    Full Text Available In recent years, protein science has been revolutionized by the discovery of intrinsically disordered proteins (IDPs. In contrast to the classical paradigm that a given protein sequence corresponds to a defined structure and an associated function, we now know that proteins can be functional in the absence of a stable three-dimensional structure. In many cases, disordered proteins or protein regions become structured, at least locally, upon interacting with their physiological partners. Many, sometimes conflicting, hypotheses have been put forward regarding the interaction mechanisms of IDPs and the potential advantages of disorder for protein-protein interactions. Whether disorder may increase, as proposed e.g. in the fly-casting hypothesis, or decrease binding rates, increase or decrease binding specificity, or what role pre-formed structure might play in interactions involving IDPs (conformational selection vs. induced fit, are subjects of intense debate. Experimentally, these questions remain difficult to address. Here, we review experimental studies of binding mechanisms of IDPs using NMR spectroscopy and transient kinetic techniques, as well as the underlying theoretical concepts and numerical methods that can be applied to describe these interactions at the atomic level. The available literature suggests that the kinetic and thermodynamic parameters characterizing interactions involving IDPs can vary widely and that there may be no single common mechanism that can explain the different binding modes observed experimentally. Rather, disordered proteins appear to make combined use of features such as pre-formed structure and flexibility, depending on the individual system and the functional context.

  18. Binding induced conformational changes of proteins correlate with their intrinsic fluctuations: a case study of antibodies

    Directory of Open Access Journals (Sweden)

    Keskin Ozlem

    2007-05-01

    Full Text Available Abstract Background How antibodies recognize and bind to antigens can not be totally explained by rigid shape and electrostatic complimentarity models. Alternatively, pre-existing equilibrium hypothesis states that the native state of an antibody is not defined by a single rigid conformation but instead with an ensemble of similar conformations that co-exist at equilibrium. Antigens bind to one of the preferred conformations making this conformation more abundant shifting the equilibrium. Results Here, two antibodies, a germline antibody of 36–65 Fab and a monoclonal antibody, SPE7 are studied in detail to elucidate the mechanism of antibody-antigen recognition and to understand how a single antibody recognizes different antigens. An elastic network model, Anisotropic Network Model (ANM is used in the calculations. Pre-existing equilibrium is not restricted to apply to antibodies. Intrinsic fluctuations of eight proteins, from different classes of proteins, such as enzymes, binding and transport proteins are investigated to test the suitability of the method. The intrinsic fluctuations are compared with the experimentally observed ligand induced conformational changes of these proteins. The results show that the intrinsic fluctuations obtained by theoretical methods correlate with structural changes observed when a ligand is bound to the protein. The decomposition of the total fluctuations serves to identify the different individual modes of motion, ranging from the most cooperative ones involving the overall structure, to the most localized ones. Conclusion Results suggest that the pre-equilibrium concept holds for antibodies and the promiscuity of antibodies can also be explained this hypothesis: a limited number of conformational states driven by intrinsic motions of an antibody might be adequate to bind to different antigens.

  19. Quantifying team cooperation through intrinsic multi-scale measures: respiratory and cardiac synchronization in choir singers and surgical teams.

    Science.gov (United States)

    Hemakom, Apit; Powezka, Katarzyna; Goverdovsky, Valentin; Jaffer, Usman; Mandic, Danilo P

    2017-12-01

    A highly localized data-association measure, termed intrinsic synchrosqueezing transform (ISC), is proposed for the analysis of coupled nonlinear and non-stationary multivariate signals. This is achieved based on a combination of noise-assisted multivariate empirical mode decomposition and short-time Fourier transform-based univariate and multivariate synchrosqueezing transforms. It is shown that the ISC outperforms six other combinations of algorithms in estimating degrees of synchrony in synthetic linear and nonlinear bivariate signals. Its advantage is further illustrated in the precise identification of the synchronized respiratory and heart rate variability frequencies among a subset of bass singers of a professional choir, where it distinctly exhibits better performance than the continuous wavelet transform-based ISC. We also introduce an extension to the intrinsic phase synchrony (IPS) measure, referred to as nested intrinsic phase synchrony (N-IPS), for the empirical quantification of physically meaningful and straightforward-to-interpret trends in phase synchrony. The N-IPS is employed to reveal physically meaningful variations in the levels of cooperation in choir singing and performing a surgical procedure. Both the proposed techniques successfully reveal degrees of synchronization of the physiological signals in two different aspects: (i) precise localization of synchrony in time and frequency (ISC), and (ii) large-scale analysis for the empirical quantification of physically meaningful trends in synchrony (N-IPS).

  20. Biventricular pacing with ventricular fusion by intrinsic activation in cardiac resynchronization therapy.

    Science.gov (United States)

    Guo, Tao; Li, Ruijie; Zhang, Limei; Luo, Zhiling; Zhao, Ling; Yang, Jun; Pu, Lijin; Hua, Baotong

    2015-05-13

    We sought to evaluate the impact of biventricular (BiV) pacing with ventricular fusion by intrinsic atrioventricular nodal (AVN) conduction (BiV + intrinsic pacing) on clinical outcomes in patients with chronic heart failure (CHF) receiving cardiac resynchronization therapy (CRT).A total of 44 patients were randomized to receive either BiV or BiV + intrinsic pacing for one month. Echocardiographic optimization was performed for the BiV pacing mode, while the BiV + intrinsic pacing mode was achieved by titrating AV delay under electrocardiography (ECG) monitoring. Symptoms, quality of life, ECG, echocardiography, and cardiovascular events were recorded at baseline and the end of the follow-up for each pacing mode.Patients undergoing BiV + intrinsic pacing mode had shorter QRS duration compared to those with conventional BiV pacing (118.4 ± 21.6 ms versus 146.4 ± 5.3 ms, P Heart Failure Questionnaire (MLHFQ) scores (12.5 ± 6.6 versus 18.2 ± 12.3, P = 0.0001).Treating CHF patients with BiV+intrinsic pacing resulted in improved cardiac function and quality of life. BiV + intrinsic pacing can be used in CHF patients with sinus rhythm and normal AV nodal conduction to improve CRT efficacy.

  1. Probing local density inhomogeneities in the circumstellar disk of a Be star using the new spectro-astrometry mode at the Keck interferometer

    OpenAIRE

    Pott, J. -U.; Woillez, J.; Ragland, S.; Wizinowich, P. L.; Eisner, J. A.; Monnier, J. D.; Akeson, R. L.; Ghez, A. M.; Graham, J. R.; Hillenbrand, L. A.; Millan-Gabet, R.; Appleby, E.; Berkey, B.; Colavita, M. M.; Cooper, A.

    2010-01-01

    We report on the successful science verification phase of a new observing mode at the Keck interferometer, which provides a line-spread function width and sampling of 150km/s at K'-band, at a current limiting magnitude of K'~7mag with spatial resolution of lam/2B ~2.7mas and a measured differential phase stability of unprecedented precision (3mrad at K=5mag, which represents 3uas on sky or a centroiding precision of 10^-3). The scientific potential of this mode is demonstrated by the presente...

  2. [Empirical mode of combination of the wavelet threshold filtering and empirical mode decomposition (EMD) based on energy estimate].

    Science.gov (United States)

    Li, Xin; Wang, Huihui; Wang, Yueru; Zhao, Fangfang

    2011-12-01

    According to the frequency overlapping of intrinsic mode function (IMF) based on the temporal and spatial filtering of empirical mode decomposition (EMD), which will lead to the question of useful signals and noises filtered together, we proposed a method that numbers of IMF is determined by energy estimate, temporal and spatial filtering combing wavelet threshold and EMD integrating wavelet local signal characteristics of time and scale domain. This method not only used multi-resolution wavelet transform features, but also combined the EMD and Hilbert decomposition of the adaptive spectral analysis of instantaneous frequency and significance of the relationship between energy, so as to solve the problem of useful signal being weakened. With MIT/BIH ECG database standard data subjects, experimental results showed it was an effective method of data processing for handling this type of physiological signals under strong noise.

  3. Characterization of Partial Intrinsic Symmetries

    NARCIS (Netherlands)

    Shehu, Aurela; Brunton, Alan; Wuhrer, Stefanie; Wand, Michael

    2014-01-01

    We present a mathematical framework and algorithm for characterizing and extracting partial intrinsic symmetries of surfaces, which is a fundamental building block for many modern geometry processing algorithms. Our goal is to compute all “significant” symmetry information of the shape, which we

  4. Reading: Intrinsic versus Extrinsic Motivation.

    Science.gov (United States)

    Ediger, Marlow

    Much debate centers on motivating student in reading achievement. Should students feel motivated from within (intrinsic motivation), or is it better to have extrinsic motivation whereby external stimuli are used to help learners achieve optimally in reading? This paper aims to analyze the two points of view about motivating students in reading…

  5. Intrinsic volumes of symmetric cones

    OpenAIRE

    Amelunxen, Dennis; Bürgisser, Peter

    2012-01-01

    We compute the intrinsic volumes of the cone of positive semidefinite matrices over the real numbers, over the complex numbers, and over the quaternions, in terms of integrals related to Mehta's integral. Several applications for the probabilistic analysis of semidefinite programming are given.

  6. Acoustic resonance spectroscopy intrinsic seals

    International Nuclear Information System (INIS)

    Olinger, C.T.; Burr, T.; Vnuk, D.R.

    1994-01-01

    We have begun to quantify the ability of acoustic resonance spectroscopy (ARS) to detect the removal and replacement of the lid of a simulated special nuclear materials drum. Conceptually, the acoustic spectrum of a container establishcs a baseline fingerprint, which we refer to as an intrinsic seal, for the container. Simply removing and replacing the lid changes some of the resonant frequencies because it is impossible to exactly duplicate all of the stress patterns between the lid and container. Preliminary qualitative results suggested that the ARS intrinsic seal could discriminate between cases where a lid has or has not been removed. The present work is directed at quantifying the utility of the ARS intrinsic seal technique, including the technique's sensitivity to ''nuisance'' effects, such as temperature swings, movement of the container, and placement of the transducers. These early quantitative tests support the potential of the ARS intrinsic seal application, but also reveal a possible sensitivity to nuisance effects that could limit environments or conditions under which the technique is effective

  7. Intrinsic Motivation in Physical Education

    Science.gov (United States)

    Davies, Benjamin; Nambiar, Nathan; Hemphill, Caroline; Devietti, Elizabeth; Massengale, Alexandra; McCredie, Patrick

    2015-01-01

    This article describes ways in which educators can use Harter's perceived competence motivation theory, the achievement goal theory, and self-determination theory to develop students' intrinsic motivation to maintain physical fitness, as demonstrated by the Sound Body Sound Mind curriculum and proven effective by the 2013 University of…

  8. Semisupervised Support Vector Machines With Tangent Space Intrinsic Manifold Regularization.

    Science.gov (United States)

    Sun, Shiliang; Xie, Xijiong

    2016-09-01

    Semisupervised learning has been an active research topic in machine learning and data mining. One main reason is that labeling examples is expensive and time-consuming, while there are large numbers of unlabeled examples available in many practical problems. So far, Laplacian regularization has been widely used in semisupervised learning. In this paper, we propose a new regularization method called tangent space intrinsic manifold regularization. It is intrinsic to data manifold and favors linear functions on the manifold. Fundamental elements involved in the formulation of the regularization are local tangent space representations, which are estimated by local principal component analysis, and the connections that relate adjacent tangent spaces. Simultaneously, we explore its application to semisupervised classification and propose two new learning algorithms called tangent space intrinsic manifold regularized support vector machines (TiSVMs) and tangent space intrinsic manifold regularized twin SVMs (TiTSVMs). They effectively integrate the tangent space intrinsic manifold regularization consideration. The optimization of TiSVMs can be solved by a standard quadratic programming, while the optimization of TiTSVMs can be solved by a pair of standard quadratic programmings. The experimental results of semisupervised classification problems show the effectiveness of the proposed semisupervised learning algorithms.

  9. Mode decomposition evolution equations.

    Science.gov (United States)

    Wang, Yang; Wei, Guo-Wei; Yang, Siyang

    2012-03-01

    Partial differential equation (PDE) based methods have become some of the most powerful tools for exploring the fundamental problems in signal processing, image processing, computer vision, machine vision and artificial intelligence in the past two decades. The advantages of PDE based approaches are that they can be made fully automatic, robust for the analysis of images, videos and high dimensional data. A fundamental question is whether one can use PDEs to perform all the basic tasks in the image processing. If one can devise PDEs to perform full-scale mode decomposition for signals and images, the modes thus generated would be very useful for secondary processing to meet the needs in various types of signal and image processing. Despite of great progress in PDE based image analysis in the past two decades, the basic roles of PDEs in image/signal analysis are only limited to PDE based low-pass filters, and their applications to noise removal, edge detection, segmentation, etc. At present, it is not clear how to construct PDE based methods for full-scale mode decomposition. The above-mentioned limitation of most current PDE based image/signal processing methods is addressed in the proposed work, in which we introduce a family of mode decomposition evolution equations (MoDEEs) for a vast variety of applications. The MoDEEs are constructed as an extension of a PDE based high-pass filter (Europhys. Lett., 59(6): 814, 2002) by using arbitrarily high order PDE based low-pass filters introduced by Wei (IEEE Signal Process. Lett., 6(7): 165, 1999). The use of arbitrarily high order PDEs is essential to the frequency localization in the mode decomposition. Similar to the wavelet transform, the present MoDEEs have a controllable time-frequency localization and allow a perfect reconstruction of the original function. Therefore, the MoDEE operation is also called a PDE transform. However, modes generated from the present approach are in the spatial or time domain and can be

  10. Aberrant Intrinsic Activity and Connectivity in Cognitively Normal Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Deborah L. Harrington

    2017-06-01

    Full Text Available Disturbances in intrinsic activity during resting-state functional MRI (rsfMRI are common in Parkinson’s disease (PD, but have largely been studied in a priori defined subnetworks. The cognitive significance of abnormal intrinsic activity is also poorly understood, as are abnormalities that precede the onset of mild cognitive impairment. To address these limitations, we leveraged three different analytic approaches to identify disturbances in rsfMRI metrics in 31 cognitively normal PD patients (PD-CN and 30 healthy adults. Subjects were screened for mild cognitive impairment using the Movement Disorders Society Task Force Level II criteria. Whole-brain data-driven analytic approaches first analyzed the amplitude of low-frequency intrinsic fluctuations (ALFF and regional homogeneity (ReHo, a measure of local connectivity amongst functionally similar regions. We then examined if regional disturbances in these metrics altered functional connectivity with other brain regions. We also investigated if abnormal rsfMRI metrics in PD-CN were related to brain atrophy and executive, visual organization, and episodic memory functioning. The results revealed abnormally increased and decreased ALFF and ReHo in PD-CN patients within the default mode network (posterior cingulate, inferior parietal cortex, parahippocampus, entorhinal cortex, sensorimotor cortex (primary motor, pre/post-central gyrus, basal ganglia (putamen, caudate, and posterior cerebellar lobule VII, which mediates cognition. For default mode network regions, we also observed a compound profile of altered ALFF and ReHo. Most regional disturbances in ALFF and ReHo were associated with strengthened long-range interactions in PD-CN, notably with regions in different networks. Stronger long-range functional connectivity in PD-CN was also partly expanded to connections that were outside the networks of the control group. Abnormally increased activity and functional connectivity appeared to have a

  11. Intrinsic spin dynamics in optically excited nanoscale magnetic tunnel junction arrays restored by dielectric coating

    Science.gov (United States)

    Jaris, M.; Yahagi, Y.; Mahato, B. K.; Dhuey, S.; Cabrini, S.; Nikitin, V.; Stout, J.; Hawkins, A. R.; Schmidt, H.

    2016-11-01

    We report the all-optical observation of intrinsic spin dynamics and extraction of magnetic material parameters from arrays of sub-100 nm spin-transfer torque magnetic random access memory (STT-MRAM) devices with a CoFeB/MgO interface. To this end, the interference of surface acoustic waves with time-resolved magneto-optic signals via magneto-elastic coupling was suppressed using a dielectric coating. The efficacy of this method is demonstrated experimentally and via modeling on a nickel nanomagnet array. The magnetization dynamics for both coated nickel and STT-MRAM arrays shows a restored field-dependent Kittel mode from which the effective damping can be extracted. We observe an increased low-field damping due to extrinsic contributions from magnetic inhomogeneities and variations in the nanomagnet shape, while the intrinsic Gilbert damping remains unaffected by patterning. The data are in excellent agreement with a local resonance model and have direct implications for the design of STT-MRAM devices as well as other nanoscale spintronic technologies.

  12. Intrinsic regulation of enteroendocrine fate by Numb.

    Science.gov (United States)

    Sallé, Jérémy; Gervais, Louis; Boumard, Benjamin; Stefanutti, Marine; Siudeja, Katarzyna; Bardin, Allison J

    2017-07-03

    How terminal cell fates are specified in dynamically renewing adult tissues is not well understood. Here we explore terminal cell fate establishment during homeostasis using the enteroendocrine cells (EEs) of the adult Drosophila midgut as a paradigm. Our data argue against the existence of local feedback signals, and we identify Numb as an intrinsic regulator of EE fate. Our data further indicate that Numb, with alpha-adaptin, acts upstream or in parallel of known regulators of EE fate to limit Notch signaling, thereby facilitating EE fate acquisition. We find that Numb is regulated in part through its asymmetric and symmetric distribution during stem cell divisions; however, its de novo synthesis is also required during the differentiation of the EE cell. Thus, this work identifies Numb as a crucial factor for cell fate choice in the adult Drosophila intestine. Furthermore, our findings demonstrate that cell-intrinsic control mechanisms of terminal cell fate acquisition can result in a balanced tissue-wide production of terminally differentiated cell types. © 2017 The Authors.

  13. Intrinsic position uncertainty impairs overt search performance.

    Science.gov (United States)

    Semizer, Yelda; Michel, Melchi M

    2017-08-01

    Uncertainty regarding the position of the search target is a fundamental component of visual search. However, due to perceptual limitations of the human visual system, this uncertainty can arise from intrinsic, as well as extrinsic, sources. The current study sought to characterize the role of intrinsic position uncertainty (IPU) in overt visual search and to determine whether it significantly limits human search performance. After completing a preliminary detection experiment to characterize sensitivity as a function of visual field position, observers completed a search task that required localizing a Gabor target within a field of synthetic luminance noise. The search experiment included two clutter conditions designed to modulate the effect of IPU across search displays of varying set size. In the Cluttered condition, the display was tiled uniformly with feature clutter to maximize the effects of IPU. In the Uncluttered condition, the clutter at irrelevant locations was removed to attenuate the effects of IPU. Finally, we derived an IPU-constrained ideal searcher model, limited by the IPU measured in human observers. Ideal searchers were simulated based on the detection sensitivity and fixation sequences measured for individual human observers. The IPU-constrained ideal searcher predicted performance trends similar to those exhibited by the human observers. In the Uncluttered condition, performance decreased steeply as a function of increasing set size. However, in the Cluttered condition, the effect of IPU dominated and performance was approximately constant as a function of set size. Our findings suggest that IPU substantially limits overt search performance, especially in crowded displays.

  14. Modes of Governing and Policy of Local and Regional Governments Supporting Local Low-Carbon Energy Initiatives; Exploring the Cases of the Dutch Regions of Overijssel and Fryslân

    NARCIS (Netherlands)

    Warbroek, W.D.B.; Hoppe, T.

    2017-01-01

    Recent scholarly attention shows increasing involvement of local low-carbon energy initiatives (LLCEIs) in governance and policy, in particular in relation to innovations regarding low-carbon energy and energy efficiency. The future perspective of active citizenship in the production of locally

  15. Intrinsic Ambipolarity and Rotation in Stellarators

    International Nuclear Information System (INIS)

    Helander, P.; Simakov, A. N.

    2008-01-01

    It is shown that collisional plasma transport is intrinsically ambipolar only in quasiaxisymmetric or quasihelically symmetric magnetic configurations. Only in such fields can the plasma rotate freely, and then only in the direction of quasisymmetry. In a non-quasi-symmetric magnetic field, the average radial electric field is determined by parallel viscosity, which in turn is usually governed by collisional processes. Locally, the radial electric field may be affected by turbulent Reynolds stress producing zonal flows, but on a radial average taken over several ion gyroradii, it is determined by parallel viscosity, at least if the turbulence is electrostatic and obeys the conventional gyrokinetic orderings. This differs from the situation in a tokamak, where there is no flow damping by parallel viscosity in the symmetry direction and the turbulent Reynolds stress may affect the global radial electric field

  16. Three-dimensional integral equation approach to light scattering, extinction cross sections, local density of states, and quasi-normal modes

    DEFF Research Database (Denmark)

    de Lasson, Jakob Rosenkrantz; Mørk, Jesper; Kristensen, Philip Trøst

    2013-01-01

    scatterers in a homogeneous background medium. In addition, we show how several physically important quantities may readily be calculated with the formalism. These quantities include the extinction cross section, the total Green’s tensor, the projected local density of states, and the Purcell factor as well...

  17. Small reactor operating mode

    International Nuclear Information System (INIS)

    Snell, V.G.

    1997-01-01

    There is a potential need for small reactors in the future for applications such as district heating, electricity production at remote sites, and desalination. Nuclear power can provide these at low cost and with insignificant pollution. The economies required by the small scale application, and/or the remote location, require a review of the size and location of the operating staff. Current concepts range all the way from reactors which are fully automatic, and need no local attention for days or weeks, to those with reduced local staff. In general the less dependent a reactor is on local human intervention, the greater its dependence on intrinsic safety features such as passive decay heat removal, low-stored energy and limited reactivity speed and depth in the control systems. A case study of the design and licensing of the SLOWPOKE Energy System heating reactor is presented. (author)

  18. Detecting Nosocomial Intrinsic Infections through Relating Bacterial ...

    African Journals Online (AJOL)

    Sierra Leone Journal of Biomedical Research ... Surgical procedures often lead to both intrinsic and extrinsic infections. ... This study demonstrated surgical procedures as precursory to intrinsic infections and that bacterial pathogens found on wounds and endogenous indicators of surgery are links to intrinsic infection.

  19. Gaussian mode selection with intracavity diffractive optics

    CSIR Research Space (South Africa)

    Litvin, IA

    2009-10-01

    Full Text Available of internal aperture. However, the power loss discrimination between the low order modes is often poor, and the small beam waist results in poor power extraction. Conversely, if an unstable configuration is employed, the mode volume is large and mode... discrimination good, but this is at the expense of high intrinsic loss for the oscillating modes, making such cavities suitable only for lasers with high gain. A major advance to overcome such problems was the introduction of so–called graded–phase mirrors [1...

  20. Nouveaux modes de coordination des acteurs dans le développement local: cas des zones rurales au Bénin

    Directory of Open Access Journals (Sweden)

    Bernard G. Hounmenou

    2003-10-01

    Full Text Available Les politiques de développement en cours dans plusieurs pays du sud, notamment dans ceux de l’Afrique sub-saharienne ont amorcé un nouveau tournant à partir de la fin des années 1980. A la faveur de l’instauration du climat de démocratie dans plusieurs de ces pays à partir de cette période, nombre d’entre eux ont procédé à de profondes réformes, donnant à la société civile et aux populations à la base, un droit de regard plus important dans la conduite des affaires les concernant. L’une des manifestations les plus importantes de ces réformes se traduit par la mise en œuvre de la décentralisation. Ce processus vise entre autres, la prise en compte des réalités locales et la responsabilisation des communautés à la base dans la gestion de leur développement. Il s’agit en d’autres termes, de favoriser le renforcement des capacités des populations locales, en vue de leur permettre de prendre en charge de façon durable, la gestion de leurs propres affaires dans le cadre de la gouvernance participative. Amorcé en janvier 1993, avec les états généraux de l’administration territoriale, le processus de la décentralisation au Bénin n’a connu sa phase de concrétisation qu’avec les élections et l’installation des élus locaux en début 2003. En prélude à l’avènement de la décentralisation, plusieurs localités béninoises font l’objet, depuis le milieu des années 1990, d’expériences d’appui au développement des communautés locales. C’est le cas notamment, des villages des départements de l’Atlantique et des Collines. A travers ces expériences, se mettent en place, divers dispositifs de gouvernance locale au sein des systèmes locaux d’action publique relatifs aux localités rurales. Il s’agit notamment, des comités villageois de suivi ou de gestion, des dispositifs de comités villageois de développement dans le département de l’Atlantique, et du dispositif des projets de

  1. A New Method for Nonlinear and Nonstationary Time Series Analysis: The Empirical Mode Decomposition Method

    Science.gov (United States)

    Huang, Norden E.; Zukor, Dorothy J. (Technical Monitor)

    2001-01-01

    A new method for analyzing nonlinear and nonstationary data has been developed. The key part of the method is the Empirical Mode Decomposition method with which any complicated data set can be decomposed into a finite and often small number of Intrinsic Mode Functions (IMF). An IMF is defined as any function having the same numbers of zero-crossing and extrema, and also having symmetric envelopes defined by the local maxima and minima respectively. The IMF also admits well-behaved Hilbert transform. This decomposition method is adaptive, and, therefore, highly efficient. Since the decomposition is based on the local characteristic time scale of the data, it is applicable to nonlinear and nonstationary processes. With the Hilbert transform, the Intrinsic Mode Functions yield instantaneous frequencies as functions of time that give sharp identifications of imbedded structures. The final presentation of the results is an energy-frequency-time distribution, designated as the Hilbert Spectrum. Classical nonlinear system models are used to illustrate the roles played by the nonlinear and nonstationary effects in the energy-frequency-time distribution.

  2. Local thermal energy as a structural indicator in glasses.

    Science.gov (United States)

    Zylberg, Jacques; Lerner, Edan; Bar-Sinai, Yohai; Bouchbinder, Eran

    2017-07-11

    Identifying heterogeneous structures in glasses-such as localized soft spots-and understanding structure-dynamics relations in these systems remain major scientific challenges. Here, we derive an exact expression for the local thermal energy of interacting particles (the mean local potential energy change caused by thermal fluctuations) in glassy systems by a systematic low-temperature expansion. We show that the local thermal energy can attain anomalously large values, inversely related to the degree of softness of localized structures in a glass, determined by a coupling between internal stresses-an intrinsic signature of glassy frustration-anharmonicity and low-frequency vibrational modes. These anomalously large values follow a fat-tailed distribution, with a universal exponent related to the recently observed universal [Formula: see text] density of states of quasilocalized low-frequency vibrational modes. When the spatial thermal energy field-a "softness field"-is considered, this power law tail manifests itself by highly localized spots, which are significantly softer than their surroundings. These soft spots are shown to be susceptible to plastic rearrangements under external driving forces, having predictive powers that surpass those of the normal modes-based approach. These results offer a general, system/model-independent, physical/observable-based approach to identify structural properties of quiescent glasses and relate them to glassy dynamics.

  3. Local thermal energy as a structural indicator in glasses

    Science.gov (United States)

    Zylberg, Jacques; Lerner, Edan; Bar-Sinai, Yohai; Bouchbinder, Eran

    2017-07-01

    Identifying heterogeneous structures in glasses—such as localized soft spots—and understanding structure-dynamics relations in these systems remain major scientific challenges. Here, we derive an exact expression for the local thermal energy of interacting particles (the mean local potential energy change caused by thermal fluctuations) in glassy systems by a systematic low-temperature expansion. We show that the local thermal energy can attain anomalously large values, inversely related to the degree of softness of localized structures in a glass, determined by a coupling between internal stresses—an intrinsic signature of glassy frustration—anharmonicity and low-frequency vibrational modes. These anomalously large values follow a fat-tailed distribution, with a universal exponent related to the recently observed universal ω4ω4 density of states of quasilocalized low-frequency vibrational modes. When the spatial thermal energy field—a “softness field”—is considered, this power law tail manifests itself by highly localized spots, which are significantly softer than their surroundings. These soft spots are shown to be susceptible to plastic rearrangements under external driving forces, having predictive powers that surpass those of the normal modes-based approach. These results offer a general, system/model-independent, physical/observable-based approach to identify structural properties of quiescent glasses and relate them to glassy dynamics.

  4. Intrinsic cylindrical and spherical waves

    International Nuclear Information System (INIS)

    Ludlow, I K

    2008-01-01

    Intrinsic waveforms associated with cylindrical and spherical Bessel functions are obtained by eliminating the factors responsible for the inverse radius and inverse square radius laws of wave power per unit area of wavefront. The resulting expressions are Riccati-Bessel functions for both cases and these can be written in terms of amplitude and phase functions of order v and wave variable z. When z is real, it is shown that a spatial phase angle of the intrinsic wave can be defined and this, together with its amplitude function, is systematically investigated for a range of fixed orders and varying z. The derivatives of Riccati-Bessel functions are also examined. All the component functions exhibit different behaviour in the near field depending on the order being less than, equal to or greater than 1/2. Plots of the phase angle can be used to display the locations of the zeros of the general Riccati-Bessel functions and lead to new relations concerning the ordering of the real zeros of Bessel functions and the occurrence of multiple zeros when the argument of the Bessel function is fixed

  5. Intrinsic periodicity: the forgotten lesson of quantum mechanics

    International Nuclear Information System (INIS)

    Dolce, Donatello

    2013-01-01

    Wave-particle duality, together with the concept of elementary particles, was introduced by de Broglie in terms of intrinsically periodic phenomena. However, after nearly 90 years, the physical origin of such undulatory mechanics remains unrevealed. We propose a natural realization of the de Broglie periodic phenomenon in terms of harmonic vibrational modes associated to space-time periodicities. In this way we find that, similarly to a vibrating string or a particle in a box, the intrinsic recurrence imposed as a constraint to elementary particles represents a fully consistent quantization condition. The resulting cyclic dynamics formally match ordinary relativistic Quantum Mechanics in both the canonical and Feynman formulations. Interactions are introduced in a geometrodynamical way, similarly to general relativity, by simply considering that variations of kinematical state can be equivalently described in terms of modulations of space-time recurrences, as known from undulatory mechanics. We present this novel quantization prescription from an historical prospective.

  6. Time-dependent transport of a localized surface plasmon through a linear array of metal nanoparticles: Precursor and normal mode contributions

    Science.gov (United States)

    Compaijen, P. J.; Malyshev, V. A.; Knoester, J.

    2018-02-01

    We theoretically investigate the time-dependent transport of a localized surface plasmon excitation through a linear array of identical and equidistantly spaced metal nanoparticles. Two different signals propagating through the array are found: one traveling with the group velocity of the surface plasmon polaritons of the system and damped exponentially, and the other running with the speed of light and decaying in a power-law fashion, as x-1 and x-2 for the transversal and longitudinal polarizations, respectively. The latter resembles the Sommerfeld-Brillouin forerunner and has not been identified in previous studies. The contribution of this signal dominates the plasmon transport at large distances. In addition, even though this signal is spread in the propagation direction and has the lateral dimension larger than the wavelength, the field profile close to the chain axis does not change with distance, indicating that this part of the signal is confined to the array.

  7. Les contributions des associations au mode local de régulation et les inégalités entre les régions

    Directory of Open Access Journals (Sweden)

    Marie Bouchard

    2003-05-01

    Full Text Available Les auteurs s’intéressent à la contribution des organismes de lutte contre la pauvreté au système régional de régulation dans une zone métropolitaine et une zone rurale périphérique toutes deux défavorisées. L’analyse comparée de ces organismes montrent que ceux-ci présentent des capacités et des limites différenciées sur le plan socioculturel et sur le plan des mécanismes de régulation politique pour contribuer au développement régional dans une perspective de lutte à la pauvreté. Des pistes d’intervention sont proposées afin d’accroître la contribution de ces organismes au développement local.

  8. Inhibition of Intrinsic Thrombin Generation

    Directory of Open Access Journals (Sweden)

    Thomas W. Stief MD

    2006-01-01

    Full Text Available Background The contact phase of coagulation is of physiologic/pathophysiologic importance, whenever unphysiologic polynegative substances such as cell fragments (microparticles get in contact with blood. There are several clinically used inhibitors of intrinsic thrombin generation. Here the inhibitory concentrations 50% (IC50 of these anticoagulants are measured by the highly specific thrombin generation assay INCA. Methods Unfrozen pooled normal citrated plasma in polystyrole tubes was supplemented at 23°C in duplicate with 0–2 IU/ml low molecular weight heparin (dalteparin, 0–2 IU/ml unfractionated heparin, 0–500 KIU/ml aprotinin, or 0–40 mM arginine. 50 μl plasma or 1 IU/ml thrombin standard were pipetted into a polystyrole microtiter plate with flat bottom. 5 μl SiO 2 /CaCl 2 - reagent (INCA activator were added and after 0–30 min incubation at 37°C 100 μl 2.5 M arginine, pH 8.6, were added; arginine inhibits hemostasis activation and depolymerizes generated fibrin within 20 min at 23°C. The in the physiologic 37°C incubation phase generated thrombin was then chromogenically detected. The intra-assay CV values were < 5%. Results and Discussion The approximate IC50 were 0.01 IU/ml dalteparin, 0.02 IU/ml heparin, 25 KIU/ml aprotinin, and 12 mM arginine. The efficiency of any anticoagulant on intrinsic thrombin generation should be measured for each individual patient. Abbreviations IIa, thrombin; δA, increase in absorbance; APTT, activated partial thromboplastin time; CRT, coagulation reaction time (at 37°C in water-bath; F-wells, polystyrole microtiter plates with flat bottom; IC50, inhibitory concentration 50%; INCA, intrinsic coagulation activity assay; IU, international units; KIU, kallikrein inhibiting unis; LMWH, low molecular weight heparin; mA, milli-absorbance units; PSL, pathromtin SL®; RT, room temperature (23°C; U-wells, polystyrole microtiter plates with round bottom.

  9. Intrinsic rotation with gyrokinetic models

    International Nuclear Information System (INIS)

    Parra, Felix I.; Barnes, Michael; Catto, Peter J.; Calvo, Iván

    2012-01-01

    The generation of intrinsic rotation by turbulence and neoclassical effects in tokamaks is considered. To obtain the complex dependences observed in experiments, it is necessary to have a model of the radial flux of momentum that redistributes the momentum within the tokamak in the absence of a preexisting velocity. When the lowest order gyrokinetic formulation is used, a symmetry of the model precludes this possibility, making small effects in the gyroradius over scale length expansion necessary. These effects that are usually small become important for momentum transport because the symmetry of the lowest order gyrokinetic formulation leads to the cancellation of the lowest order momentum flux. The accuracy to which the gyrokinetic equation needs to be obtained to retain all the physically relevant effects is discussed.

  10. Computer implemented empirical mode decomposition method apparatus, and article of manufacture utilizing curvature extrema

    Science.gov (United States)

    Huang, Norden Eh (Inventor); Shen, Zheng (Inventor)

    2003-01-01

    A computer implemented physical signal analysis method is includes two essential steps and the associated presentation techniques of the results. All the steps exist only in a computer: there are no analytic expressions resulting from the method. The first step is a computer implemented Empirical Mode Decomposition to extract a collection of Intrinsic Mode Functions (IMF) from nonlinear, nonstationary physical signals based on local extrema and curvature extrema. The decomposition is based on the direct extraction of the energy associated with various intrinsic time scales in the physical signal. Expressed in the IMF's, they have well-behaved Hilbert Transforms from which instantaneous frequencies can be calculated. The second step is the Hilbert Transform. The final result is the Hilbert Spectrum. Thus, the invention can localize any event on the time as well as the frequency axis. The decomposition can also be viewed as an expansion of the data in terms of the IMF's. Then, these IMF's, based on and derived from the data, can serve as the basis of that expansion. The local energy and the instantaneous frequency derived from the IMF's through the Hilbert transform give a full energy-frequency-time distribution of the data which is designated as the Hilbert Spectrum.

  11. Failure Modes

    DEFF Research Database (Denmark)

    Jakobsen, K. P.; Burcharth, H. F.; Ibsen, Lars Bo

    1999-01-01

    The present appendix contains the derivation of ten different limit state equations divided on three different failure modes. Five of the limit state equations can be used independently of the characteristics of the subsoil, whereas the remaining five can be used for either drained or undrained...

  12. Incentives and intrinsic motivation in healthcare

    Directory of Open Access Journals (Sweden)

    Mikel Berdud

    2016-11-01

    Conclusions: The conclusions could act as a guide to support the optimal design of incentive policies and schemes within health organisations when healthcare professionals are intrinsically motivated.

  13. Quasi-periodic oscillations and the global modes of relativistic, MHD accretion discs

    Science.gov (United States)

    Dewberry, Janosz W.; Latter, Henrik N.; Ogilvie, Gordon I.

    2018-02-01

    The high-frequency quasi-periodic oscillations (HFQPOs) that punctuate the light curves of X-ray binary systems present a window onto the intrinsic properties of stellar-mass black holes and hence a testbed for general relativity. One explanation for these features is that relativistic distortion of the accretion disc's differential rotation creates a trapping region in which inertial waves (r-modes) might grow to observable amplitudes. Local analyses, however, predict that large-scale magnetic fields push this trapping region to the inner disc edge, where conditions may be unfavorable for r-mode growth. We revisit this problem from a pseudo-Newtonian but fully global perspective, deriving linearized equations describing a relativistic, magnetized accretion flow, and calculating normal modes with and without vertical density stratification. In an unstratified model, the choice of vertical wavenumber determines the extent to which vertical magnetic fields drive the r-modes toward the inner edge. In a global model fully incorporating density stratification, we confirm that this susceptibility to magnetic fields depends on disc thickness. Our calculations suggest that in thin discs, r-modes may remain independent of the inner disc edge for vertical magnetic fields with plasma betas as low as β ≈ 100 - 300. We posit that the appearance of r-modes in observations may be more determined by a competition between excitation and damping mechanisms near the ISCO than the modification of the trapping region by magnetic fields.

  14. Restless 'rest': intrinsic sensory hyperactivity and disinhibition in post-traumatic stress disorder.

    Science.gov (United States)

    Clancy, Kevin; Ding, Mingzhou; Bernat, Edward; Schmidt, Norman B; Li, Wen

    2017-07-01

    Post-traumatic stress disorder is characterized by exaggerated threat response, and theoretical accounts to date have focused on impaired threat processing and dysregulated prefrontal-cortex-amygdala circuitry. Nevertheless, evidence is accruing for broad, threat-neutral sensory hyperactivity in post-traumatic stress disorder. As low-level, sensory processing impacts higher-order operations, such sensory anomalies can contribute to widespread dysfunctions, presenting an additional aetiological mechanism for post-traumatic stress disorder. To elucidate a sensory pathology of post-traumatic stress disorder, we examined intrinsic visual cortical activity (based on posterior alpha oscillations) and bottom-up sensory-driven causal connectivity (Granger causality in the alpha band) during a resting state (eyes open) and a passive, serial picture viewing state. Compared to patients with generalized anxiety disorder (n = 24) and healthy control subjects (n = 20), patients with post-traumatic stress disorder (n = 25) demonstrated intrinsic sensory hyperactivity (suppressed posterior alpha power, source-localized to the visual cortex-cuneus and precuneus) and bottom-up inhibition deficits (reduced posterior→frontal Granger causality). As sensory input increased from resting to passive picture viewing, patients with post-traumatic stress disorder failed to demonstrate alpha adaptation, highlighting a rigid, set mode of sensory hyperactivity. Interestingly, patients with post-traumatic stress disorder also showed heightened frontal processing (augmented frontal gamma power, source-localized to the superior frontal gyrus and dorsal cingulate cortex), accompanied by attenuated top-down inhibition (reduced frontal→posterior causality). Importantly, not only did suppressed alpha power and bottom-up causality correlate with heightened frontal gamma power, they also correlated with increased severity of sensory and executive dysfunctions (i.e. hypervigilance and impulse control

  15. Geochemical indicators of intrinsic bioremediation

    International Nuclear Information System (INIS)

    Borden, R.C.; Gomez, C.A.; Becker, M.T.

    1995-01-01

    A detailed field investigation has been completed at a gasoline-contaminated aquifer near Rocky Point, NC, to examine possible indicators of intrinsic bioremediation and identify factors that may significantly influence the rae and extent of bioremediation. The dissolved plume of benzene, toluene, ethylbenzene, and xylene (BTEX) in ground water is naturally degrading. Toluene and o-xylene are most rapidly degraded followed by m-, p-xylene, and benzene. Ethylbenzene appears to degrade very slowly under anaerobic conditions present in the center of the plume. The rate and extent of biodegradation appears to be strongly influenced by the type and quantity of electron acceptors present in the aquifer. At the upgradient edge of the plume, nitrate, ferric iron, and oxygen are used as terminal electron acceptors during hydrocarbon biodegradation. The equivalent of 40 to 50 mg/l of hydrocarbon is degraded based on the increase in dissolved CO 2 relative to background ground water. Immediately downgradient of the source area, sulfate and iron are the dominant electron acceptors. Toluene and o-xylene are rapidly removed in this region. Once the available oxygen, nitrate, and sulfate are consumed, biodegradation is limited and appears to be controlled by mixing and aerobic biodegradation at the plume fringes

  16. Protein intrinsic disorder in plants.

    Science.gov (United States)

    Pazos, Florencio; Pietrosemoli, Natalia; García-Martín, Juan A; Solano, Roberto

    2013-09-12

    To some extent contradicting the classical paradigm of the relationship between protein 3D structure and function, now it is clear that large portions of the proteomes, especially in higher organisms, lack a fixed structure and still perform very important functions. Proteins completely or partially unstructured in their native (functional) form are involved in key cellular processes underlain by complex networks of protein interactions. The intrinsic conformational flexibility of these disordered proteins allows them to bind multiple partners in transient interactions of high specificity and low affinity. In concordance, in plants this type of proteins has been found in processes requiring these complex and versatile interaction networks. These include transcription factor networks, where disordered proteins act as integrators of different signals or link different transcription factor subnetworks due to their ability to interact (in many cases simultaneously) with different partners. Similarly, they also serve as signal integrators in signaling cascades, such as those related to response to external stimuli. Disordered proteins have also been found in plants in many stress-response processes, acting as protein chaperones or protecting other cellular components and structures. In plants, it is especially important to have complex and versatile networks able to quickly and efficiently respond to changing environmental conditions since these organisms cannot escape and have no other choice than adapting to them. Consequently, protein disorder can play an especially important role in plants, providing them with a fast mechanism to obtain complex, interconnected and versatile molecular networks.

  17. Protein intrinsic disorder in plants

    Directory of Open Access Journals (Sweden)

    Florencio ePazos

    2013-09-01

    Full Text Available To some extent contradicting the classical paradigm of the relationship between protein 3D structure and function, now it is clear that large portions of the proteomes, especially in higher organisms, lack a fixed structure and still perform very important functions. Proteins completely or partially unstructured in their native (functional form are involved in key cellular processes underlain by complex networks of protein interactions. The intrinsic conformational flexibility of these disordered proteins allows them to bind multiple partners in transient interactions of high specificity and low affinity. In concordance, in plants this type of proteins has been found in processes requiring these complex and versatile interaction networks. These include transcription factor networks, where disordered proteins act as integrators of different signals or link different transcription factor subnetworks due to their ability to interact (in many cases simultaneously with different partners. Similarly, they also serve as signal integrators in signalling cascades, such as those related to response to external stimuli. Disordered proteins have also been found in plants in many stress-response processes, acting as protein chaperones or protecting other cellular components and structures. In plants, it is especially important to have complex and versatile networks able to quickly and efficiently respond to changing environmental conditions since these organisms can not escape and have no other choice than adapting to them. Consequently, protein disorder can play an especially important role in plants, providing them with a fast mechanism to obtain complex, interconnected and versatile molecular networks.

  18. Ballooning modes or Fourier modes in a toroidal plasma?

    International Nuclear Information System (INIS)

    Connor, J.W.; Taylor, J.B.

    1987-01-01

    The relationship between two different descriptions of eigenmodes in a torus is investigated. In one the eigenmodes are similar to Fourier modes in a cylinder and are highly localized near a particular rational surface. In the other they are the so-called ballooning modes that extend over many rational surfaces. Using a model that represents both drift waves and resistive interchanges the transition from one of these structures to the other is investigated. In this simplified model the transition depends on a single parameter which embodies the competition between toroidal coupling of Fourier modes (which enhances ballooning) and variation in frequency of Fourier modes from one rational surface to another (which diminishes ballooning). As the coupling is increased each Fourier mode acquires a sideband on an adjacent rational surface and these sidebands then expand across the radius to form the extended mode described by the conventional ballooning mode approximation. This analysis shows that the ballooning approximation is appropriate for drift waves in a tokamak but not for resistive interchanges in a pinch. In the latter the conventional ballooning effect is negligible but they may nevertheless show a ballooning feature. This is localized near the same rational surface as the primary Fourier mode and so does not lead to a radially extended structure

  19. Evaluating measurement invariance across assessment modes of phone interview and computer self-administered survey for the PROMIS measures in a population-based cohort of localized prostate cancer survivors.

    Science.gov (United States)

    Wang, Mian; Chen, Ronald C; Usinger, Deborah S; Reeve, Bryce B

    2017-11-01

    To evaluate measurement invariance (phone interview vs computer self-administered survey) of 15 PROMIS measures responded by a population-based cohort of localized prostate cancer survivors. Participants were part of the North Carolina Prostate Cancer Comparative Effectiveness and Survivorship Study. Out of the 952 men who took the phone interview at 24 months post-treatment, 401 of them also completed the same survey online using a home computer. Unidimensionality of the PROMIS measures was examined using single-factor confirmatory factor analysis (CFA) models. Measurement invariance testing was conducted using longitudinal CFA via a model comparison approach. For strongly or partially strongly invariant measures, changes in the latent factors and factor autocorrelations were also estimated and tested. Six measures (sleep disturbance, sleep-related impairment, diarrhea, illness impact-negative, illness impact-positive, and global satisfaction with sex life) had locally dependent items, and therefore model modifications had to be made on these domains prior to measurement invariance testing. Overall, seven measures achieved strong invariance (all items had equal loadings and thresholds), and four measures achieved partial strong invariance (each measure had one item with unequal loadings and thresholds). Three measures (pain interference, interest in sexual activity, and global satisfaction with sex life) failed to establish configural invariance due to between-mode differences in factor patterns. This study supports the use of phone-based live interviewers in lieu of PC-based assessment (when needed) for many of the PROMIS measures.

  20. A Novel Method for Mechanical Fault Diagnosis Based on Variational Mode Decomposition and Multikernel Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Zhongliang Lv

    2016-01-01

    Full Text Available A novel fault diagnosis method based on variational mode decomposition (VMD and multikernel support vector machine (MKSVM optimized by Immune Genetic Algorithm (IGA is proposed to accurately and adaptively diagnose mechanical faults. First, mechanical fault vibration signals are decomposed into multiple Intrinsic Mode Functions (IMFs by VMD. Then the features in time-frequency domain are extracted from IMFs to construct the feature sets of mixed domain. Next, Semisupervised Locally Linear Embedding (SS-LLE is adopted for fusion and dimension reduction. The feature sets with reduced dimension are inputted to the IGA optimized MKSVM for failure mode identification. Theoretical analysis demonstrates that MKSVM can approximate any multivariable function. The global optimal parameter vector of MKSVM can be rapidly identified by IGA parameter optimization. The experiments of mechanical faults show that, compared to traditional fault diagnosis models, the proposed method significantly increases the diagnosis accuracy of mechanical faults and enhances the generalization of its application.

  1. Intrinsic and collective structure of an algebraic model of molecular rotation-vibration spectra

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A.; Kirson, M.W.

    1988-11-15

    A geometrical framework is provided for a recently proposed interacting boson model of molecular rotation-vibration spectra. An intrinsic state is defined by way of a boson condensate parametrized in terms of shape variables and is used to generate an energy surface. The global minimum of the energy surface determines an equilibrium condensate which serves as the basis for an exact separation of the Hamiltonian into intrinsic and collective parts. A Bogoliubov treatment of the intrinsic part produces, in leading order, the normal modes of vibration and their frequencies, the collective degrees of freedom being represented by zero-frequency Goldstone modes associated with spontaneous symmetry breaking in the condensate. The method is very useful in interpreting numerical results of the algebraic model, in identifying the capabilities and inadequacies of the Hamiltonian, and in constructing appropriate algebraic Hamiltonians for specific molecules. copyright 1988 Academic Press, Inc.

  2. Intrinsic and collective structure of an algebraic model of molecular rotation-vibration spectra

    International Nuclear Information System (INIS)

    Leviatan, A.; Kirson, M.W.

    1988-01-01

    A geometrical framework is provided for a recently proposed interacting boson model of molecular rotation-vibration spectra. An intrinsic state is defined by way of a boson condensate parametrized in terms of shape variables and is used to generate an energy surface. The global minimum of the energy surface determines an equilibrium condensate which serves as the basis for an exact separation of the Hamiltonian into intrinsic and collective parts. A Bogoliubov treatment of the intrinsic part produces, in leading order, the normal modes of vibration and their frequencies, the collective degrees of freedom being represented by zero-frequency Goldstone modes associated with spontaneous symmetry breaking in the condensate. The method is very useful in interpreting numerical results of the algebraic model, in identifying the capabilities and inadequacies of the Hamiltonian, and in constructing appropriate algebraic Hamiltonians for specific molecules. copyright 1988 Academic Press, Inc

  3. LEADERSHIP STYLE AND EMPLOYEES' INTRINSIC JOB ...

    African Journals Online (AJOL)

    Abstract. This study investigates the impact of leadership style on employees' intrinsic job satisfaction in the Cross River State Newspaper Corporation, Calabar,. Nigeria. The study examined the problem of dissatisfaction in the work place as far as intrinsic factors of job satisfaction are concerned. Structured questionnaire ...

  4. Intrinsic bioremediation of landfills interim report

    International Nuclear Information System (INIS)

    Brigmon, R.L.; Fliermans, C.B.

    1997-01-01

    Intrinsic bioremediation is a risk management option that relies on natural biological and physical processes to contain the spread of contamination from a source. Evidence is presented in this report that intrinsic bioremediation is occurring at the Sanitary Landfill is fundamental to support incorportion into a Corrective Action Plan (CAP)

  5. Differential scanning microcalorimetry of intrinsically disordered proteins.

    Science.gov (United States)

    Permyakov, Sergei E

    2012-01-01

    Ultrasensitive differential scanning calorimetry (DSC) is an indispensable thermophysical technique enabling to get direct information on enthalpies accompanying heating/cooling of dilute biopolymer solutions. The thermal dependence of protein heat capacity extracted from DSC data is a valuable source of information on intrinsic disorder level of a protein. Application details and limitations of DSC technique in exploration of protein intrinsic disorder are described.

  6. Intrinsic bioremediation of landfills interim report

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R.L. [Westinghouse Savannah River Company, Aiken, SC (United States); Fliermans, C.B.

    1997-07-14

    Intrinsic bioremediation is a risk management option that relies on natural biological and physical processes to contain the spread of contamination from a source. Evidence is presented in this report that intrinsic bioremediation is occurring at the Sanitary Landfill is fundamental to support incorportion into a Corrective Action Plan (CAP).

  7. An Intrinsic Coordinate System for Fingerprint Matching

    NARCIS (Netherlands)

    Bazen, A.M.; Gerez, Sabih H.; Bigun, J.; Smeraldi, F.

    2001-01-01

    In this paper, an intrinsic coordinate system is proposed for fingerprints. First the fingerprint is partitioned in regular regions, which are regions that contain no singular points. In each regular region, the intrinsic coordinate system is defined by the directional field. When using the

  8. Phase space interrogation of the empirical response modes for seismically excited structures

    Science.gov (United States)

    Paul, Bibhas; George, Riya C.; Mishra, Sudib K.

    2017-07-01

    Conventional Phase Space Interrogation (PSI) for structural damage assessment relies on exciting the structure with low dimensional chaotic waveform, thereby, significantly limiting their applicability to large structures. The PSI technique is presently extended for structure subjected to seismic excitations. The high dimensionality of the phase space for seismic response(s) are overcome by the Empirical Mode Decomposition (EMD), decomposing the responses to a number of intrinsic low dimensional oscillatory modes, referred as Intrinsic Mode Functions (IMFs). Along with their low dimensionality, a few IMFs, retain sufficient information of the system dynamics to reflect the damage induced changes. The mutually conflicting nature of low-dimensionality and the sufficiency of dynamic information are taken care by the optimal choice of the IMF(s), which is shown to be the third/fourth IMFs. The optimal IMF(s) are employed for the reconstruction of the Phase space attractor following Taken's embedding theorem. The widely referred Changes in Phase Space Topology (CPST) feature is then employed on these Phase portrait(s) to derive the damage sensitive feature, referred as the CPST of the IMFs (CPST-IMF). The legitimacy of the CPST-IMF is established as a damage sensitive feature by assessing its variation with a number of damage scenarios benchmarked in the IASC-ASCE building. The damage localization capability, remarkable tolerance to noise contamination and the robustness under different seismic excitations of the feature are demonstrated.

  9. Promoting Intrinsic and Extrinsic Motivation among Chemistry Students Using Computer-Assisted Instruction

    Science.gov (United States)

    Gambari, Isiaka A.; Gbodi, Bimpe E.; Olakanmi, Eyitao U.; Abalaka, Eneojo N.

    2016-01-01

    The role of computer-assisted instruction in promoting intrinsic and extrinsic motivation among Nigerian secondary school chemistry students was investigated in this study. The study employed two modes of computer-assisted instruction (computer simulation instruction and computer tutorial instructional packages) and two levels of gender (male and…

  10. Using seismic coda waves to resolve intrinsic and scattering attenuation

    Science.gov (United States)

    Wang, W.; Shearer, P. M.

    2016-12-01

    Seismic attenuation is caused by two factors, scattering and intrinsic absorption. Characterizing scattering and absorbing properties and the power spectrum of crustal heterogeneity is a fundamental problem for informing strong ground motion estimates at high frequencies, where scattering and attenuation effects are critical. Determining the relative amount of attenuation caused by scattering and intrinsic absorption has been a long-standing problem in seismology. The wavetrain following the direct body wave phases is called the coda, which is caused by scattered energy. Many studies have analyzed the coda of local events to constrain crustal and upper-mantle scattering strength and intrinsic attenuation. Here we examine two popular attenuation inversion methods, the Multiple Lapse Time Window Method (MLTWM) and the Coda Qc Method. First, based on our previous work on California attenuation structure, we apply an efficient and accurate method, the Monte Carlo Approach, to synthesize seismic envelope functions. We use this code to generate a series of synthetic data based on several complex and realistic forward models. Although the MLTWM assumes a uniform whole space, we use the MLTWM to invert for both scattering and intrinsic attenuation from the synthetic data to test how accurately it can recover the attenuation models. Results for the coda Qc method depend on choices for the length and starting time of the coda-wave time window. Here we explore the relation between the inversion results for Qc, the windowing parameters, and the intrinsic and scattering Q structure of our synthetic model. These results should help assess the practicality and accuracy of the Multiple Lapse Time Window Method and Coda Qc Method when applied to realistic crustal velocity and attenuation models.

  11. Learning intrinsic excitability in medium spiny neurons [v2; ref status: indexed, http://f1000r.es/30b

    Directory of Open Access Journals (Sweden)

    Gabriele Scheler

    2014-02-01

    Full Text Available We present an unsupervised, local activation-dependent learning rule for intrinsic plasticity (IP which affects the composition of ion channel conductances for single neurons in a use-dependent way. We use a single-compartment conductance-based model for medium spiny striatal neurons in order to show the effects of parameterization of individual ion channels on the neuronal membrane potential-curent relationship (activation function. We show that parameter changes within the physiological ranges are sufficient to create an ensemble of neurons with significantly different activation functions. We emphasize that the effects of intrinsic neuronal modulation on spiking behavior require a distributed mode of synaptic input and can be eliminated by strongly correlated input. We show how modulation and adaptivity in ion channel conductances can be utilized to store patterns without an additional contribution by synaptic plasticity (SP. The adaptation of the spike response may result in either "positive" or "negative" pattern learning. However, read-out of stored information depends on a distributed pattern of synaptic activity to let intrinsic modulation determine spike response. We briefly discuss the implications of this conditional memory on learning and addiction.

  12. Computer implemented empirical mode decomposition method, apparatus and article of manufacture

    Science.gov (United States)

    Huang, Norden E. (Inventor)

    1999-01-01

    A computer implemented physical signal analysis method is invented. This method includes two essential steps and the associated presentation techniques of the results. All the steps exist only in a computer: there are no analytic expressions resulting from the method. The first step is a computer implemented Empirical Mode Decomposition to extract a collection of Intrinsic Mode Functions (IMF) from nonlinear, nonstationary physical signals. The decomposition is based on the direct extraction of the energy associated with various intrinsic time scales in the physical signal. Expressed in the IMF's, they have well-behaved Hilbert Transforms from which instantaneous frequencies can be calculated. The second step is the Hilbert Transform. The final result is the Hilbert Spectrum. Thus, the invention can localize any event on the time as well as the frequency axis. The decomposition can also be viewed as an expansion of the data in terms of the IMF's. Then, these IMF's, based on and derived from the data, can serve as the basis of that expansion. The local energy and the instantaneous frequency derived from the IMF's through the Hilbert transform give a full energy-frequency-time distribution of the data which is designated as the Hilbert Spectrum.

  13. Motor memory is encoded as a gain-field combination of intrinsic and extrinsic action representations.

    Science.gov (United States)

    Brayanov, Jordan B; Press, Daniel Z; Smith, Maurice A

    2012-10-24

    Actions can be planned in either an intrinsic (body-based) reference frame or an extrinsic (world-based) frame, and understanding how the internal representations associated with these frames contribute to the learning of motor actions is a key issue in motor control. We studied the internal representation of this learning in human subjects by analyzing generalization patterns across an array of different movement directions and workspaces after training a visuomotor rotation in a single movement direction in one workspace. This provided a dense sampling of the generalization function across intrinsic and extrinsic reference frames, which allowed us to dissociate intrinsic and extrinsic representations and determine the manner in which they contributed to the motor memory for a trained action. A first experiment showed that the generalization pattern reflected a memory that was intermediate between intrinsic and extrinsic representations. A second experiment showed that this intermediate representation could not arise from separate intrinsic and extrinsic learning. Instead, we find that the representation of learning is based on a gain-field combination of local representations in intrinsic and extrinsic coordinates. This gain-field representation generalizes between actions by effectively computing similarity based on the (Mahalanobis) distance across intrinsic and extrinsic coordinates and is in line with neural recordings showing mixed intrinsic-extrinsic representations in motor and parietal cortices.

  14. Threshold condition for nonlinear tearing modes in tokamaks

    International Nuclear Information System (INIS)

    Zabiego, M.F.; Callen, J.D.

    1996-04-01

    Low-mode-number tearing mode nonlinear evolution is analyzed emphasizing the need for a threshold condition, to account for observations in tokamaks. The discussion is illustrated by two models recently introduced in the literature. Introducing a threshold condition in the tearing mode stability analysis is found to reveal some bifurcation points and thus domains of intrinsic stability in the island dynamics operational space. (author)

  15. Enhanced understanding of non-axisymmetric intrinsic and controlled field impacts in tokamaks

    Science.gov (United States)

    In, Y.; Park, J.-K.; Jeon, Y. M.; Kim, J.; Park, G. Y.; Ahn, J.-W.; Loarte, A.; Ko, W. H.; Lee, H. H.; Yoo, J. W.; Juhn, J. W.; Yoon, S. W.; Park, H.; Physics Task Force in KSTAR, 3D

    2017-11-01

    An extensive study of intrinsic and controlled non-axisymmetric field (δB) impacts in KSTAR has enhanced the understanding about non-axisymmetric field physics and its implications, in particular, on resonant magnetic perturbation (RMP) physics and power threshold (P th) for L-H transition. The n  =  1 intrinsic non-axisymmetric field in KSTAR was measured to remain as low as δB/B 0 ~ 4  ×  10-5 even at high-beta plasmas (β N ~ 2), which corresponds to approximately 20% below the targeted ITER tolerance level. As for the RMP edge-localized-modes (ELM) control, robust n  =  1 RMP ELM-crash-suppression has been not only sustained for more than ~90 τ E, but also confirmed to be compatible with rotating RMP. An optimal window of radial position of lower X-point (i.e. R x   =  1.44+/- 0.02 m) proved to be quite critical to reach full n  =  1 RMP-driven ELM-crash-suppression, while a constraint of the safety factor could be relaxed (q 95  =  5 +/- 0.25). A more encouraging finding was that even when R x cannot be positioned in the optimal window, another systematic scan in the vicinity of the previously optimal R x allows for a new optimal window with relatively small variations of plasma parameters. Also, we have addressed the importance of optimal phasing (i.e. toroidal phase difference between adjacent rows) for n  =  1 RMP-driven ELM control, consistent with an ideal plasma response modeling which could predict phasing-dependent ELM suppression windows. In support of ITER RMP study, intentionally misaligned RMPs have been found to be quite effective during ELM-mitigation stage in lowering the peaks of divertor heat flux, as well as in broadening the ‘wet’ areas. Besides, a systematic survey of P th dependence on non-axisymmetric field has revealed the potential limit of the merit of low intrinsic non-axisymmetry. Considering that the ITER RMP coils are composed of 3-rows, just like in KSTAR, further 3D

  16. Edge transport and mode structure of a QCM-like fluctuation driven by the Shoelace antenna

    Science.gov (United States)

    Golfinopoulos, T.; LaBombard, B.; Brunner, D.; Terry, J. L.; Baek, S. G.; Ennever, P.; Edlund, E.; Han, W.; Burke, W. M.; Wolfe, S. M.; Irby, J. H.; Hughes, J. W.; Fitzgerald, E. W.; Granetz, R. S.; Greenwald, M. J.; Leccacorvi, R.; Marmar, E. S.; Pierson, S. Z.; Porkolab, M.; Vieira, R. F.; Wukitch, S. J.; The Alcator C-Mod Team

    2018-05-01

    The Shoelace antenna was built to drive edge fluctuations in the Alcator C-Mod tokamak, matching the wavenumber (k\\perp≈1.5 cm‑1) and frequency (30≲ f ≲ 200 kHz) of the quasi-coherent mode (QCM), which is responsible for regulating transport across the plasma boundary in the steady-state, ELM-free Enhanced D α (EDA) H-mode. Initial experiments in 2012 demonstrated that the antenna drove a resonant response in the edge plasma in steady-state EDA and transient, non-ELMy H-modes, but transport measurements were unavailable. In 2016, the Shoelace antenna was relocated to enable direct measurements of driven transport by a reciprocating Mirror Langmuir Probe, while also making available gas puff imaging and reflectometer data to provide additional radial localization of the driven fluctuation. This new data suggests a  ∼4 mm-wide mode layer centered on or just outside the separatrix. Fluctuations coherent with the antenna produced a radial electron flux with {Γ_e}/{n_e}∼4 m s‑1 in EDA H-mode, smaller than but comparable to the QCM level. But in transient ELM-free H-mode, {Γ_e}/{n_e} was an order of magnitude smaller, and driven fluctuations reduced by a factor of ≳ 3. The driven mode is quantitatively similar to the intrinsic QCM across measured spectral quantities, except that it is more coherent and weaker. This work informs the prospect of achieving control of edge transport by direct coupling to edge modes, as well as the use of such active coupling for diagnostic purposes.

  17. Intrinsic endometriosis of ureter: a case report

    International Nuclear Information System (INIS)

    Hong, Myung Sun; Kim, Ho Chul; Yun, Ku Sup; Choi, Chul Soon; Bae, Sang Hoon; Kim, Sung Yong; Shin, Hyung Sik

    1995-01-01

    Endometriosis is a rare cause of an ureteral obstruction. We report a case of intrinsic ureteral endometriosis resulting in severe hydroureteronephrosis. The diagnosis of ureteral endometriosis may be considered in women with flank pain and ureteric obstruction within true pelvis

  18. The Intrinsic Dynamics of Psychological Process

    NARCIS (Netherlands)

    Vallacher, Robin R.; van Geert, Paul; Nowak, Andrzej

    2015-01-01

    Psychological processes unfold on various timescales in accord with internally generated patterns. The intrinsic dynamism of psychological process is difficult to investigate using traditional methods emphasizing cause–effect relations, however, and therefore is rarely incorporated into social

  19. Deuterium NMR, induced and intrinsic cholesteric lyomesophases

    International Nuclear Information System (INIS)

    Alcantara, M.R.

    1982-01-01

    Induced and intrinsic cholesteric lyotropic mesophases were studied. Induced cholesteric lyomesophases based on potassium laurate (KL) system, with small amounts of cholesterol added, were studied by deuterium NMR and by polarizing microscopy. Order profiles obtained from deuterium NMR of KL perdenderated chains in both induced cholesteric and normal mesophases were compared. The intrinsic cholesteric lyotropic mesophases were based on the amphiphile potassium N-lauroyl serinate (KLNS) in the resolved levo form. The study of the type I intrinsic cholesteric mesophase was made by optical microscopy under polarized light and the type II intrinsic cholesteric lyomesophase was characterized by deuterium NMR. The new texture was explained by the use of the theory of disclinations developed for thermotropic liquid crystals, specially for cholesteric type. (M.J.C.) [pt

  20. Intrinsic and acquired resistance mechanisms in enterococcus

    Science.gov (United States)

    Hollenbeck, Brian L.; Rice, Louis B.

    2012-01-01

    Enterococci have the potential for resistance to virtually all clinically useful antibiotics. Their emergence as important nosocomial pathogens has coincided with increased expression of antimicrobial resistance by members of the genus. The mechanisms underlying antibiotic resistance in enterococci may be intrinsic to the species or acquired through mutation of intrinsic genes or horizontal exchange of genetic material encoding resistance determinants. This paper reviews the antibiotic resistance mechanisms in Enterococcus faecium and Enterococcus faecalis and discusses treatment options. PMID:23076243

  1. The intrinsic resistome of bacterial pathogens

    Directory of Open Access Journals (Sweden)

    Jorge Andrés Olivares Pacheco

    2013-04-01

    Full Text Available Intrinsically resistant bacteria have emerged as a relevant health problem in the last years. Those bacterial species, several of them with an environmental origin, present naturally a low-level susceptibility to several drugs. It has been proposed that intrinsic resistance is mainly the consequence of the impermeability of cellular envelopes, the activity of multidrug efflux pumps or the lack of appropriate targets for a given family of drugs. However, recently published articles indicate that the characteristic phenotype of susceptibility to antibiotics of a given bacterial species depends on the concerted activity of several elements, what has been named as intrinsic resistome. These determinants comprise not just classical resistance genes. Other elements, several of them involved in basic bacterial metabolic processes, are of relevance for the intrinsic resistance of bacterial pathogens. In the present review we analyse recent publications on the intrinsic resistomes of Escherichia coli and Pseudomonas aeruginosa. We present as well information on the role that global regulators of bacterial metabolism, as Crc from P. aeruginosa, may have on modulating bacterial susceptibility to antibiotics. Finally, we discuss the possibility of searching inhibitors of the intrinsic resistome in the aim of improving the activity of drugs currently in use for clinical practice.

  2. Incentives and intrinsic motivation in healthcare.

    Science.gov (United States)

    Berdud, Mikel; Cabasés, Juan M; Nieto, Jorge

    It has been established in the literature that workers within public organisations are intrinsically motivated. This paper is an empirical study of the healthcare sector using methods of qualitative analysis research, which aims to answer the following hypotheses: 1) doctors are intrinsically motivated; 2) economic incentives and control policies may undermine doctors' intrinsic motivation; and 3) well-designed incentives may encourage doctors' intrinsic motivation. We conducted semi-structured interviews à-la-Bewley with 16 doctors from Navarre's Healthcare Service (Servicio Navarro de Salud-Osasunbidea), Spain. The questions were based on current theories of intrinsic motivation and incentives to test the hypotheses. Interviewees were allowed to respond openly without time constraints. Relevant information was selected, quantified and analysed by using the qualitative concepts of saturation and codification. The results seem to confirm the hypotheses. Evidence supporting hypotheses 1 and 2 was gathered from all interviewees, as well as indications of the validity of hypothesis 3 based on interviewees' proposals of incentives. The conclusions could act as a guide to support the optimal design of incentive policies and schemes within health organisations when healthcare professionals are intrinsically motivated. Copyright © 2016 SESPAS. Publicado por Elsevier España, S.L.U. All rights reserved.

  3. Quantifying the intrinsic amount of fabrication disorder in photonic-crystal waveguides from optical far-field intensity measurements

    DEFF Research Database (Denmark)

    Garcia-Fernandez, Pedro David; Javadi, Alisa; Nielsen, Henri Thyrrestrup

    2013-01-01

    Residual disorder due to fabrication imperfections has important impact in nanophotonics where it may degrade device performance by increasing radiation loss or spontaneously trap light by Anderson localization. We propose and demonstrate experimentally a method of quantifying the intrinsic amoun...

  4. The role of dynamo fluctuations in anomalous ion heating, mode locking, and flow generation

    International Nuclear Information System (INIS)

    Terry, P.W.; Gatto, R.; Fiksel, G.; Fitzpatrick, R.; Hegna, C.C.

    2001-01-01

    Anomalous ion heating intrinsic to magnetic fluctuation-induced electron heat transport, the locking of global modes through wall conditions, and flow generation via the magnetic Reynolds stress all derive from the global, m=1 tearing modes familiar in the RFP as the dynamo modes. These important processes are investigated analytically and numerically, yielding new insights and predictions for comparison with experiment. (author)

  5. Size matters to function: Brain volume correlates with intrinsic brain activity across healthy individuals.

    Science.gov (United States)

    Qing, Zhao; Gong, Gaolang

    2016-10-01

    A fundamental issue in neuroscience is to understand the structural substrates of neural activities. Intrinsic brain activity has been increasingly recognized as an important functional activity mode and is tightly linked with various cognitive functions. Structurally, cognitive functions have also shown a relation with brain volume/size. Therefore, an association between intrinsic brain activities and brain volume/size can be hypothesized, and brain volume/size may impact intrinsic brain activity in human brains. The present study aimed to explicitly investigate this brain structure-function relationship using two large independent cohorts of 176 and 236 young adults. Structural-MRI was performed to estimate the brain volume, and resting-state functional-MRI was applied to extract the amplitude of low-frequency fluctuations (ALFF), an imaging measure of intrinsic brain activity. Intriguingly, our results revealed a robust linear correlation between whole-brain size and ALFF. Moreover, specific brain lobes/regions, including the frontal lobe, the left middle frontal gyrus, anterior cingulate gyrus, Rolandic operculum, and insula, also showed a reliable, positive volume-ALFF correlation in the two cohorts. These findings offer direct, empirical evidence of a strong association between brain size/volume and intrinsic brain activity, as well as provide novel insight into the structural substrates of the intrinsic brain activity of the human brain. Copyright © 2016 Elsevier Inc. All rights reserved.

  6. Terahertz Spectrum Analysis Based on Empirical Mode Decomposition

    Science.gov (United States)

    Su, Yunpeng; Zheng, Xiaoping; Deng, Xiaojiao

    2017-08-01

    Precise identification of terahertz absorption peaks for materials with low concentration and high attenuation still remains a challenge. Empirical mode decomposition was applied to terahertz spectrum analysis in order to improve the performance on spectral fingerprints identification. We conducted experiments on water vapor and carbon monoxide respectively with terahertz time domain spectroscopy. By comparing their absorption spectra before and after empirical mode decomposition, we demonstrated that the first-order intrinsic mode function shows absorption peaks clearly in high-frequency range. By comparing the frequency spectra of the sample signals and their intrinsic mode functions, we proved that the first-order function contains most of the original signal's energy and frequency information so that it cannot be left out or replaced by high-order functions in spectral fingerprints detection. Empirical mode decomposition not only acts as an effective supplementary means to terahertz time-domain spectroscopy but also shows great potential in discrimination of materials and prediction of their concentrations.

  7. Integrated ensemble noise-reconstructed empirical mode decomposition for mechanical fault detection

    Science.gov (United States)

    Yuan, Jing; Ji, Feng; Gao, Yuan; Zhu, Jun; Wei, Chenjun; Zhou, Yu

    2018-05-01

    A new branch of fault detection is utilizing the noise such as enhancing, adding or estimating the noise so as to improve the signal-to-noise ratio (SNR) and extract the fault signatures. Hereinto, ensemble noise-reconstructed empirical mode decomposition (ENEMD) is a novel noise utilization method to ameliorate the mode mixing and denoised the intrinsic mode functions (IMFs). Despite the possibility of superior performance in detecting weak and multiple faults, the method still suffers from the major problems of the user-defined parameter and the powerless capability for a high SNR case. Hence, integrated ensemble noise-reconstructed empirical mode decomposition is proposed to overcome the drawbacks, improved by two noise estimation techniques for different SNRs as well as the noise estimation strategy. Independent from the artificial setup, the noise estimation by the minimax thresholding is improved for a low SNR case, which especially shows an outstanding interpretation for signature enhancement. For approximating the weak noise precisely, the noise estimation by the local reconfiguration using singular value decomposition (SVD) is proposed for a high SNR case, which is particularly powerful for reducing the mode mixing. Thereinto, the sliding window for projecting the phase space is optimally designed by the correlation minimization. Meanwhile, the reasonable singular order for the local reconfiguration to estimate the noise is determined by the inflection point of the increment trend of normalized singular entropy. Furthermore, the noise estimation strategy, i.e. the selection approaches of the two estimation techniques along with the critical case, is developed and discussed for different SNRs by means of the possible noise-only IMF family. The method is validated by the repeatable simulations to demonstrate the synthetical performance and especially confirm the capability of noise estimation. Finally, the method is applied to detect the local wear fault

  8. Thermal image filtering by bi-dimensional empirical mode decomposition

    Science.gov (United States)

    Gavriloaia, Bogdan-Mihai; Vizireanu, Constantin-Radu; Fratu, Octavian; Mara, Constantin; Vizireanu, Dragos-Nicolae; Preda, Radu; Gavriloaia, Gheorghe

    2015-02-01

    The abnormal function of cells can be detected by anatomic or physiological registrations. Most of modern approaches, as ultrasound, RMN or CT, show anatomic parametric modifications of tissues or organs. They highlight areas with a larger diameter 1 cm. In the case of skin or superficial cancers, local temperature is different, and it can be put out by thermal imager. Medical imaging is a leading role in modern diagnosis for abnormal or normal tissues or organs. Some information has to be improved for a better diagnosis by reducing or removing some unwanted information like noise affecting image texture. The traditional technologies for medical image enhancement use spatial or frequency domain methods, but whole image processing will hide both partial and specific information for human signals. A particular kind of medical images is represented by thermal imaging. Recently, these images were used for skin or superficial cancers diagnosis, but very clear outlines of certain alleged affected areas need to be shown. Histogram equalization cannot highlights the edges and control the effects of enhancement. A new filtering method was introduced by Huang by using the empirical mode decomposition, EMD. An improved filtering method for thermal images, based on EMD, is presented in this paper, and permits to analyze nonlinear and non-stationary data by the adaptive decomposition into intrinsic mode surfaces. The results, evaluated by SNR ratios, are compared with other filtering methods.

  9. Systematics of adiabatic modes: flat universes

    Science.gov (United States)

    Pajer, E.; Jazayeri, S.

    2018-03-01

    Adiabatic modes are cosmological perturbations that are locally indistinguishable from a (large) change of coordinates. At the classical level, they provide model independent solutions. At the quantum level, they lead to soft theorems for cosmological correlators. We present a systematic derivation of adiabatic modes in spatially-flat cosmological backgrounds with asymptotically-perfect fluids. We find several new adiabatic modes including vector, time-dependent tensor and time-dependent scalar modes. The new vector and tensor modes decay with time in standard cosmologies but are the leading modes in contracting universes. We present a preliminary derivation of the related soft theorems. In passing, we discuss a distinction between classical and quantum adiabatic modes, we clarify the subtle nature of Weinberg's second adiabatic mode and point out that the adiabatic nature of a perturbation is a gauge dependent statement.

  10. Helimagnon Resonances in an Intrinsic Chiral Magnonic Crystal

    Science.gov (United States)

    Weiler, Mathias; Aqeel, Aisha; Mostovoy, Maxim; Leonov, Andrey; Geprägs, Stephan; Gross, Rudolf; Huebl, Hans; Palstra, Thomas T. M.; Goennenwein, Sebastian T. B.

    2017-12-01

    We experimentally study magnetic resonances in the helical and conical magnetic phases of the chiral magnetic insulator Cu2OSeO3 at the temperature T =5 K . Using a broadband microwave spectroscopy technique based on vector network analysis, we identify three distinct sets of helimagnon resonances in the frequency range 2 GHz ≤f ≤20 GHz with low magnetic damping α ≤0.003 . The extracted resonance frequencies are in accordance with calculations of the helimagnon band structure found in an intrinsic chiral magnonic crystal. The periodic modulation of the equilibrium spin direction that leads to the formation of the magnonic crystal is a direct consequence of the chiral magnetic ordering caused by the Dzyaloshinskii-Moriya interaction. The mode coupling in the magnonic crystal allows excitation of helimagnons with wave vectors that are multiples of the spiral wave vector.

  11. Altered intrinsic connectivity of the auditory cortex in congenital amusia.

    Science.gov (United States)

    Leveque, Yohana; Fauvel, Baptiste; Groussard, Mathilde; Caclin, Anne; Albouy, Philippe; Platel, Hervé; Tillmann, Barbara

    2016-07-01

    Congenital amusia, a neurodevelopmental disorder of music perception and production, has been associated with abnormal anatomical and functional connectivity in a right frontotemporal pathway. To investigate whether spontaneous connectivity in brain networks involving the auditory cortex is altered in the amusic brain, we ran a seed-based connectivity analysis, contrasting at-rest functional MRI data of amusic and matched control participants. Our results reveal reduced frontotemporal connectivity in amusia during resting state, as well as an overconnectivity between the auditory cortex and the default mode network (DMN). The findings suggest that the auditory cortex is intrinsically more engaged toward internal processes and less available to external stimuli in amusics compared with controls. Beyond amusia, our findings provide new evidence for the link between cognitive deficits in pathology and abnormalities in the connectivity between sensory areas and the DMN at rest. Copyright © 2016 the American Physiological Society.

  12. The dynamic multisite interactions between two intrinsically disordered proteins

    KAUST Repository

    Wu, Shaowen

    2017-05-11

    Protein interactions involving intrinsically disordered proteins (IDPs) comprise a variety of binding modes, from the well characterized folding upon binding to dynamic fuzzy complex. To date, most studies concern the binding of an IDP to a structured protein, while the Interaction between two IDPs is poorly understood. In this study, we combined NMR, smFRET, and molecular dynamics (MD) simulation to characterize the interaction between two IDPs, the C-terminal domain (CTD) of protein 4.1G and the nuclear mitotic apparatus (NuMA) protein. It is revealed that CTD and NuMA form a fuzzy complex with remaining structural disorder. Multiple binding sites on both proteins were identified by MD and mutagenesis studies. Our study provides an atomic scenario in which two IDPs bearing multiple binding sites interact with each other in dynamic equilibrium. The combined approach employed here could be widely applicable for investigating IDPs and their dynamic interactions.

  13. High-mode-number ballooning modes in a heliotron/torsatron system: 2, Stability

    Energy Technology Data Exchange (ETDEWEB)

    Nakajima, N.

    1996-05-01

    In heliotron/torsantron systems that have a large Shafranov shift, the local magnetic shear is found to have no stabilizing effect on high-mode-number ballooning modes at the outer side of the torus, even in the region where the global shear is stellarator-like in nature. The disappearance of this stabilization, in combination with the compression of the flux surfaces at the outer side of the torus, leads at relatively low values of the plasma pressure to significant modifications of the stabilizing effect due to magnetic field-line bending on high-mode-number ballooning modes-specifically, that the field-line bending stabilization can be remarkably suppressed or enhanced. In an equilibrium that is slightly Mercier-unstable or completely Mercier-stable due to peaked pressure profiles, such as those used in standaxd stability calculations or observed in experiments on the Compact Helical System, high-mode-number ballooning modes are destabilized due to these modified stability effects, with their eigenfunctions highly localized along the field line. Highly localized mode structures such as these cause the ballooning mode eigenvalues {omega} {sup 2} to have a strong field line dependence through the strong dependence of the local magnetic curvature, such that the level surfaces of {omega} {sup 2} ({psi}, {theta} {sub k}, {alpha}), (<0) become spheroids in ({theta} {sub k}, {alpha}) space, where {psi} labels flux surfaces and {theta} {sub k} is the radial wavenumber. Because the spheroidal level surfaces for unstable eigenvalues are surrounded by level surfaces for stable eigenvalues of high-mode-number toroidal Alfven eigenmodes, those high-mode-number ballooning modes never lead to low-mode-number modes. In configuration space, these high- mode-number modes are localized in a single toroidal pitch of the helical coils, and hence they may experience substantial stabilization due to finite Larmor radius effects.

  14. Intrinsic Energy Dissipation Limits in Nano and Micromechanical Resonators

    Science.gov (United States)

    Iyer, Srikanth Subramanian

    Resonant microelectromechanical Systems (MEMS) have enabled miniaturization of high-performance inertial sensors, radio-frequency filters, timing references and mass-based chemical sensors. Despite the increasing prevalence of MEMS resonators for these applications, the energy dissipation in these structures is not well-understood. Accurate prediction of the energy loss and the resulting quality factor (Q) has significant design implications because it is directly related to device performance metrics including sensitivity for resonant sensors, bandwidth for radio-frequency filters and phase-noise for timing references. In order to assess the future potential for MEMS resonators it is critically important to evaluate the energy dissipation limits, which will dictate the ultimate performance resonant MEMS devices can achieve. This work focuses on the derivation and evaluation of the intrinsic mechanical energy dissipation limit for single-crystal nano and micromechanical resonators due to anharmonic phonon-phonon scattering in the Akhiezer regime. The energy loss is derived using perturbation theory and the linearized Boltzmann transport equation for phonons, and includes the direction and polarization dependent mode-Gruneisen parameters in order to capture the strain-induced anharmonicity among phonon branches. Evaluation of the quality factor limit reveals that Akhiezer damping, previously thought to depend only on material properties, has a strong dependence on crystal orientation and resonant mode shape. The robust model provides a dissipation limit for all resonant modes including shear-mode vibrations, which have significantly reduced energy loss because dissipative phonon-phonon scattering is restricted to volume-preserving phonon branches, indicating that Lame or wine-glass mode resonators will have the highest upper limit on mechanical efficiency. Finally, the analytical dissipation model is integrated with commercial finite element software in order to

  15. Suppression of intrinsic roughness in encapsulated graphene

    Science.gov (United States)

    Thomsen, Joachim Dahl; Gunst, Tue; Gregersen, Søren Schou; Gammelgaard, Lene; Jessen, Bjarke Sørensen; Mackenzie, David M. A.; Watanabe, Kenji; Taniguchi, Takashi; Bøggild, Peter; Booth, Timothy J.

    2017-07-01

    Roughness in graphene is known to contribute to scattering effects which lower carrier mobility. Encapsulating graphene in hexagonal boron nitride (hBN) leads to a significant reduction in roughness and has become the de facto standard method for producing high-quality graphene devices. We have fabricated graphene samples encapsulated by hBN that are suspended over apertures in a substrate and used noncontact electron diffraction measurements in a transmission electron microscope to measure the roughness of encapsulated graphene inside such structures. We furthermore compare the roughness of these samples to suspended bare graphene and suspended graphene on hBN. The suspended heterostructures display a root mean square (rms) roughness down to 12 pm, considerably less than that previously reported for both suspended graphene and graphene on any substrate and identical within experimental error to the rms vibrational amplitudes of carbon atoms in bulk graphite. Our first-principles calculations of the phonon bands in graphene/hBN heterostructures show that the flexural acoustic phonon mode is localized predominantly in the hBN layer. Consequently, the flexural displacement of the atoms in the graphene layer is strongly suppressed when it is supported by hBN, and this effect increases when graphene is fully encapsulated.

  16. Functions of intrinsic disorder in transmembrane proteins

    DEFF Research Database (Denmark)

    Kjaergaard, Magnus; Kragelund, Birthe B.

    2017-01-01

    mechanisms. (3) Trafficking of membrane proteins. (4) Transient membrane associations. (5) Post-translational modifications most notably phosphorylation and (6) disorder-linked isoform dependent function. We finish the review by discussing the future challenges facing the membrane protein community regarding......Intrinsic disorder is common in integral membrane proteins, particularly in the intracellular domains. Despite this observation, these domains are not always recognized as being disordered. In this review, we will discuss the biological functions of intrinsically disordered regions of membrane...... proteins, and address why the flexibility afforded by disorder is mechanistically important. Intrinsically disordered regions are present in many common classes of membrane proteins including ion channels and transporters; G-protein coupled receptors (GPCRs), receptor tyrosine kinases and cytokine...

  17. Management Control, Intrinsic Motivation and Creativity

    DEFF Research Database (Denmark)

    Godt Gregersen, Mikkel

    of the conclusion is that intrinsic motivation and management control can coexist under the conditions that all three basic needs, i.e. autonomy, competence and relatedness, are supported. This can happen when control takes point of departure in the individual employee. The second part of the conclusion......This thesis consists of a cape and three papers. The overall research question is: How can intrinsic motivation and management control coexist in a creative environment and how can coordination be possible in such a context? The cape ties together the research done in the three papers....... It is divided into six sections. The first section introduces the concepts of intrinsic motivation, creativity and management control. This is followed by a section on management control in a creative context. These two sections frame the thesis and introduce the setting in which the research has been done...

  18. On the intrinsic timescales of temporal variability in measurements of the surface solar radiation

    Science.gov (United States)

    Bengulescu, Marc; Blanc, Philippe; Wald, Lucien

    2018-01-01

    This study is concerned with the intrinsic temporal scales of the variability in the surface solar irradiance (SSI). The data consist of decennial time series of daily means of the SSI obtained from high-quality measurements of the broadband solar radiation impinging on a horizontal plane at ground level, issued from different Baseline Surface Radiation Network (BSRN) ground stations around the world. First, embedded oscillations sorted in terms of increasing timescales of the data are extracted by empirical mode decomposition (EMD). Next, Hilbert spectral analysis is applied to obtain an amplitude-modulation-frequency-modulation (AM-FM) representation of the data. The time-varying nature of the characteristic timescales of variability, along with the variations in the signal intensity, are thus revealed. A novel, adaptive null hypothesis based on the general statistical characteristics of noise is employed in order to discriminate between the different features of the data, those that have a deterministic origin and those being realizations of various stochastic processes. The data have a significant spectral peak corresponding to the yearly variability cycle and feature quasi-stochastic high-frequency variability components, irrespective of the geographical location or of the local climate. Moreover, the amplitude of this latter feature is shown to be modulated by variations in the yearly cycle, which is indicative of nonlinear multiplicative cross-scale couplings. The study has possible implications on the modeling and the forecast of the surface solar radiation, by clearly discriminating the deterministic from the quasi-stochastic character of the data, at different local timescales.

  19. Hot Carrier-Assisted Intrinsic Photoresponse in Graphene

    Science.gov (United States)

    Gabor, Nathaniel; Song, Justin; Ma, Qiong; Nair, Nityan; Taychatanapat, Thiti; Watanabe, Kenji; Taniguchi, Takashi; Levitov, Leonid; Jarillo-Herrero, Pablo

    2012-02-01

    Graphene is considered an excellent candidate for photodetection and energy harvesting applications due to its broadband optical response and high internal quantum efficiency, yet measurements have not clearly determined the photocurrent generation mechanism. Here, we report on the intrinsic photoresponse of dual-gated monolayer and bilayer graphene p-n junction devices. Local laser excitation of wavelength 850 nm at the p-n interface leads to striking six-fold photovoltage patterns as a function of bottom- and top-gate voltages. These patterns, together with the measured spatial and density dependence of the photoresponse, provide strong evidence that non-local hot carrier transport, rather than the photovoltaic effect, dominates the intrinsic photoresponse in graphene [1,2] The hot carrier regime manifests as a strong photo-thermoelectric effect in which the photogenerated carrier population remains hot while the lattice stays cool. [1] Science v. 334, p. 648-652 (2011). [2] Nano Lett. ASAP 10.1021/nl202318u (2011).

  20. Unattended nuclear systems for local energy supply

    International Nuclear Information System (INIS)

    Lynch, G.F.; Bancroft, A.R.; Hilborn, J.W.; McDougall, D.S.; Ohta, M.M.

    1988-02-01

    This paper describes recent developments in a small nuclear heat and electricity production system - the SLOWPOKE Energy System - that make it possible to locate the system close to the load, and that could have a major impact on local energy supply. The most important unique features arising from these developments are walk-away safety and the ability to operate in an unattended mode. Walk-away safety means that radiological protection is provided by intrinsic characteristics and does not depend on either engineered safety systems or operator intervention. This, in our view, is essential to public acceptance. The capability for unattended operation results from self-regulation; however, the performance can be remotely monitored. The SLOWPOKE Energy System consists of a water-filled pool, operating at atmospheric pressure, which cools and moderates a beryllium-reflected thermal reactor that is fuelled with 100 to 400 kg of low-enriched uranium. The pool water also provides shielding from radioactive materials trapped in the fuel. Heat is drawn from the pool and transferred either to a building hot-water distribution system or to an organic liquid which is converted to vapour to drive a turbine-generator unit. Heating loads between 2 qnd 10 MWt, and electrical loads up to 1 MWe can be satisfied. SLOWPOKE is a dramatic departure from conventional nuclear power reactors. Its nuclear heat source is intrinsically simple, having only one moving part: a solid neutron absorber which is slowly withdrawn from the reactor to balance the fuel burnup. Its power is self-regulated and excessive heat production cannot occur, even for the most severe combinations of system failure. Cooling of the fuel is assured by natural physical processes that do not depend on mechanical components such as pumps. These intrinsic characteristics assure public safety and ultra high reliability

  1. Unattended nuclear systems for local energy supply

    International Nuclear Information System (INIS)

    Lynch, G.F.; Bancroft, A.R.; Hilborn, J.W.; McDougall, D.S.; Ohta, M.M.

    1986-10-01

    This paper describes recent developments in a small nuclear heat and electricity production system - the SLOWPOKE energy system - that make it possible to locate the system close to the load, and that could have a major impact on local energy supply. The most important unique features arising from these developments are walk-away safety and the ability to operate in an unattended mode. Walk-away safety means that radiological protection is provided by intrinsic characteristics and does not depend on either engineered safety systems or operator intervention. This, in our view, is essential to public acceptance. The capability for unattended operation results from self-regulation, however the performance can be remotely monitored. The SLOWPOKE energy system consists of a water-filled pool, operating at atmospheric pressure, which cools and moderates a beryllium-reflected thermal reactor that is fuelled with 100 to 400 kg of low enriched uranium. The pool water also provides shielding from radioactive materials trapped in the fuel. Heat is drawn from the pool and transferred either to a building hot-water distribution system or to an organic liquid which is converted to vapour to drive a turbine-generator unit. Heating loads between 2 and 10 MWt, and electrical loads up to 1 MWe can be satisfied. SLOWPOKE is a dramatic departure from conventional nuclear power reactors. Its nuclear heat source is intrinsically simple, having only one moving part: a solid neutron absorber which is slowly withdrawn from the reactor to balance the fuel burnup. Its power is self-regulated and excessive heat production cannot occur, even for the most severe combinations of system failure. Cooling of the fuel is assured by natural physical processes that do not depend on mechanical components such as pumps. These intrinsic characteristics assure public safety and ultra high reliability. (author)

  2. Insulin aggregation tracked by its intrinsic TRES

    Science.gov (United States)

    Chung, Li Hung C.; Birch, David J. S.; Vyshemirsky, Vladislav; Ryadnov, Maxim G.; Rolinski, Olaf J.

    2017-12-01

    Time-resolved emission spectra (TRES) have been used to detect conformational changes of intrinsic tyrosines within bovine insulin at a physiological pH. The approach offers the ability to detect the initial stages of insulin aggregation at the molecular level. The data analysis has revealed the existence of at least three fluorescent species undergoing dielectric relaxation and significant spectral changes due to insulin aggregation. The results indicate the suitability of the intrinsic TRES approach for insulin studies and for monitoring its stability during storage and aggregation in insulin delivery devices.

  3. Intrinsic viscosity of a suspension of cubes

    KAUST Repository

    Mallavajula, Rajesh K.

    2013-11-06

    We report on the viscosity of a dilute suspension of cube-shaped particles. Irrespective of the particle size, size distribution, and surface chemistry, we find empirically that cubes manifest an intrinsic viscosity [η]=3.1±0.2, which is substantially higher than the well-known value for spheres, [η]=2.5. The orientation-dependent intrinsic viscosity of cubic particles is determined theoretically using a finite-element solution of the Stokes equations. For isotropically oriented cubes, these calculations show [η]=3.1, in excellent agreement with our experimental observations. © 2013 American Physical Society.

  4. Intrinsic entropy perturbations from the dark sector

    Science.gov (United States)

    Celoria, Marco; Comelli, Denis; Pilo, Luigi

    2018-03-01

    Perfect fluids are modeled by using an effective field theory approach which naturally gives a self-consistent and unambiguous description of the intrinsic non-adiabatic contribution to pressure variations. We study the impact of intrinsic entropy perturbation on the superhorizon dynamics of the curvature perturbation Script R in the dark sector. The dark sector, made of dark matter and dark energy is described as a single perfect fluid. The non-perturbative vorticity's dynamics and the Weinberg theorem violation for perfect fluids are also studied.

  5. A model of intrinsic symmetry breaking

    International Nuclear Information System (INIS)

    Ge, Li; Li, Sheng; George, Thomas F.; Sun, Xin

    2013-01-01

    Different from the symmetry breaking associated with a phase transition, which occurs when the controlling parameter is manipulated across a critical point, the symmetry breaking presented in this Letter does not need parameter manipulation. Instead, the system itself suddenly undergoes symmetry breaking at a certain time during its evolution, which is intrinsic symmetry breaking. Through a polymer model, it is revealed that the origin of the intrinsic symmetry breaking is nonlinearity, which produces instability at the instance when the evolution crosses an inflexion point, where this instability breaks the original symmetry

  6. Threshold condition for nonlinear tearing modes in tokamaks

    International Nuclear Information System (INIS)

    Zabiego, M.F.; Callen, J.D.

    1996-03-01

    Low-mode-number tearing, mode nonlinear evolution is analyzed emphasizing the need for a threshold condition, to account for observations in tokamaks. The discussion is illustrated by two models recently introduced in the literature. The models can be compared with the available data and/or serve as a basis for planning some experiments in order to either test theory (by means of beta-limit scaling laws, as proposed in this paper) or attempt to control undesirable tearing modes. Introducing a threshold condition in the tearing mode stability analysis is found to reveal some bifurcation points and thus domains of intrinsic stability in the island dynamics operational space

  7. Empirical mode decomposition apparatus, method and article of manufacture for analyzing biological signals and performing curve fitting

    Science.gov (United States)

    Huang, Norden E. (Inventor)

    2004-01-01

    A computer implemented physical signal analysis method includes four basic steps and the associated presentation techniques of the results. The first step is a computer implemented Empirical Mode Decomposition that extracts a collection of Intrinsic Mode Functions (IMF) from nonlinear, nonstationary physical signals. The decomposition is based on the direct extraction of the energy associated with various intrinsic time scales in the physical signal. Expressed in the IMF's, they have well-behaved Hilbert Transforms from which instantaneous frequencies can be calculated. The second step is the Hilbert Transform which produces a Hilbert Spectrum. Thus, the invention can localize any event on the time as well as the frequency axis. The decomposition can also be viewed as an expansion of the data in terms of the IMF's. Then, these IMF's, based on and derived from the data, can serve as the basis of that expansion. The local energy and the instantaneous frequency derived from the IMF's through the Hilbert transform give a full energy-frequency-time distribution of the data which is designated as the Hilbert Spectrum. The third step filters the physical signal by combining a subset of the IMFs. In the fourth step, a curve may be fitted to the filtered signal which may not have been possible with the original, unfiltered signal.

  8. The Sodium-Potassium Pump Controls the Intrinsic Firing of the Cerebellar Purkinje Neuron

    Science.gov (United States)

    Forrest, Michael D.; Wall, Mark J.; Press, Daniel A.; Feng, Jianfeng

    2012-01-01

    In vitro, cerebellar Purkinje cells can intrinsically fire action potentials in a repeating trimodal or bimodal pattern. The trimodal pattern consists of tonic spiking, bursting, and quiescence. The bimodal pattern consists of tonic spiking and quiescence. It is unclear how these firing patterns are generated and what determines which firing pattern is selected. We have constructed a realistic biophysical Purkinje cell model that can replicate these patterns. In this model, Na+/K+ pump activity sets the Purkinje cell's operating mode. From rat cerebellar slices we present Purkinje whole cell recordings in the presence of ouabain, which irreversibly blocks the Na+/K+ pump. The model can replicate these recordings. We propose that Na+/K+ pump activity controls the intrinsic firing mode of cerbellar Purkinje cells. PMID:23284664

  9. Frustration-induced protein intrinsic disorder.

    Science.gov (United States)

    Matsushita, Katsuyoshi; Kikuchi, Macoto

    2013-03-14

    Spontaneous folding into a specific native structure is the most important property of protein to perform their biological functions within organisms. Spontaneous folding is understood on the basis of an energy landscape picture based on the minimum frustration principle. Therefore, frustration seemingly only leads to protein functional disorder. However, frustration has recently been suggested to have a function in allosteric regulation. Functional frustration has the possibility to be a key to our deeper understanding of protein function. To explore another functional frustration, we theoretically examined structural frustration, which is designed to induce intrinsic disorder of a protein and its function through the coupled folding and binding. We extended the Wako-Saitô-Muñoz-Eaton model to take into account a frustration effect. With the model, we analyzed the binding part of neuron-restrictive silencer factor and showed that designed structural frustration in it induces intrinsic disorder. Furthermore, we showed that the folding and the binding are cooperative in interacting with a target protein. The cooperativity enables an intrinsically disordered protein to exhibit a sharp switch-like folding response to binding chemical potential change. Through this switch-like response, the structural frustration may contribute to the regulation function of interprotein interaction of the intrinsically disordered protein.

  10. INTRINSIC AND EXTRINSIC MOTIVATION IN THE SELECTION ...

    African Journals Online (AJOL)

    A psychological perspective is considered that applies intrinsic and extrinsic motivational concepts to communication phenomena. The paper also tries to develop an analytical understanding of human communication-related behavior with respect to the two types of motives. Proposals are also put forward to communication ...

  11. Intrinsic and Extrinsic Motivation among Collegiate Instrumentalists

    Science.gov (United States)

    Diaz, Frank M.

    2010-01-01

    The purpose of this study was to gather and compare information on measures of intrinsic and extrinsic motivation among instrumentalists enrolled in collegiate ensembles. A survey instrument was developed to gather information concerning demographic data and responses to questions on motivational preference. Participants were undergraduate and…

  12. Original Paper Detecting Nosocomial Intrinsic Infections through ...

    African Journals Online (AJOL)

    2011-04-20

    Apr 20, 2011 ... Key Words: Bacterial pathogens, Endogenous indicators, NosocomiaI infection, Surgery. Received 30 October 2010/ Accepted 30 March 2011. INTRODUCTION. Micro-organisms from intrinsic and extrinsic sources have been known to cause nosocomial infections (CDC, 1991). The human body enables.

  13. Organisational Learning and Employees' Intrinsic Motivation

    Science.gov (United States)

    Remedios, Richard; Boreham, Nick

    2004-01-01

    This study examined the effects of organisational learning initiatives on employee motivation. Four initiatives consistent with theories of organisational learning were a priori ranked in terms of concepts that underpin intrinsic-motivation theory. Eighteen employees in a UK petrochemical company were interviewed to ascertain their experiences of…

  14. Intrinsic Motivation, Organizational Justice, and Creativity

    Science.gov (United States)

    Hannam, Kalli; Narayan, Anupama

    2015-01-01

    For employees to generate creative ideas that are not only original, but also useful to their company, they must interact with their workplace environment to determine organizational needs. Therefore, it is important to consider aspects of the individual as well as their environment when studying creativity. Intrinsic motivation, a predictor of…

  15. Discovery of Intrinsic Primitives on Triangle Meshes

    KAUST Repository

    Solomon, Justin

    2011-04-01

    The discovery of meaningful parts of a shape is required for many geometry processing applications, such as parameterization, shape correspondence, and animation. It is natural to consider primitives such as spheres, cylinders and cones as the building blocks of shapes, and thus to discover parts by fitting such primitives to a given surface. This approach, however, will break down if primitive parts have undergone almost-isometric deformations, as is the case, for example, for articulated human models. We suggest that parts can be discovered instead by finding intrinsic primitives, which we define as parts that posses an approximate intrinsic symmetry. We employ the recently-developed method of computing discrete approximate Killing vector fields (AKVFs) to discover intrinsic primitives by investigating the relationship between the AKVFs of a composite object and the AKVFs of its parts. We show how to leverage this relationship with a standard clustering method to extract k intrinsic primitives and remaining asymmetric parts of a shape for a given k. We demonstrate the value of this approach for identifying the prominent symmetry generators of the parts of a given shape. Additionally, we show how our method can be modified slightly to segment an entire surface without marking asymmetric connecting regions and compare this approach to state-of-the-art methods using the Princeton Segmentation Benchmark. © 2011 The Author(s).

  16. Free-Boundary Resistive Modes in Tokamaks

    NARCIS (Netherlands)

    Huysmans, G. T. A.; Goedbloed, J. P.; Kerner, W.

    1993-01-01

    There exist a number of observations of magnetohydrodynamic (MHD) activity that can be related to resistive MHD modes localized near the plasma boundary. To study the stability of these modes, a free boundary description of the plasma is essential. The resistive plasma-vacuum boundary conditions

  17. Normalized modes at selected points without normalization

    Science.gov (United States)

    Kausel, Eduardo

    2018-04-01

    As every textbook on linear algebra demonstrates, the eigenvectors for the general eigenvalue problem | K - λM | = 0 involving two real, symmetric, positive definite matrices K , M satisfy some well-defined orthogonality conditions. Equally well-known is the fact that those eigenvectors can be normalized so that their modal mass μ =ϕT Mϕ is unity: it suffices to divide each unscaled mode by the square root of the modal mass. Thus, the normalization is the result of an explicit calculation applied to the modes after they were obtained by some means. However, we show herein that the normalized modes are not merely convenient forms of scaling, but that they are actually intrinsic properties of the pair of matrices K , M, that is, the matrices already "know" about normalization even before the modes have been obtained. This means that we can obtain individual components of the normalized modes directly from the eigenvalue problem, and without needing to obtain either all of the modes or for that matter, any one complete mode. These results are achieved by means of the residue theorem of operational calculus, a finding that is rather remarkable inasmuch as the residues themselves do not make use of any orthogonality conditions or normalization in the first place. It appears that this obscure property connecting the general eigenvalue problem of modal analysis with the residue theorem of operational calculus may have been overlooked up until now, but which has in turn interesting theoretical implications.Á

  18. Intrinsic to extrinsic phonon lifetime transition in a GaAs-AlAs superlattice.

    Science.gov (United States)

    Hofmann, F; Garg, J; Maznev, A A; Jandl, A; Bulsara, M; Fitzgerald, E A; Chen, G; Nelson, K A

    2013-07-24

    We have measured the lifetimes of two zone-center longitudinal acoustic phonon modes, at 320 and 640 GHz, in a 14 nm GaAs/2 nm AlAs superlattice structure. By comparing measurements at 296 and 79 K we separate the intrinsic contribution to phonon lifetime determined by phonon-phonon scattering from the extrinsic contribution due to defects and interface roughness. At 296 K, the 320 GHz phonon lifetime has approximately equal contributions from intrinsic and extrinsic scattering, whilst at 640 GHz it is dominated by extrinsic effects. These measurements are compared with intrinsic and extrinsic scattering rates in the superlattice obtained from first-principles lattice dynamics calculations. The calculated room-temperature intrinsic lifetime of longitudinal phonons at 320 GHz is in agreement with the experimentally measured value of 0.9 ns. The model correctly predicts the transition from predominantly intrinsic to predominantly extrinsic scattering; however the predicted transition occurs at higher frequencies. Our analysis indicates that the 'interfacial atomic disorder' model is not entirely adequate and that the observed frequency dependence of the extrinsic scattering rate is likely to be determined by a finite correlation length of interface roughness.

  19. Viscous, Resistive Magnetorotational Modes

    DEFF Research Database (Denmark)

    Pessah, Martin Elias; Chan, Chi-kwan

    2008-01-01

    We carry out a comprehensive analysis of the behavior of the magnetorotational instability (MRI) in viscous, resistive plasmas. We find exact, non-linear solutions of the non-ideal magnetohydrodynamic (MHD) equations describing the local dynamics of an incompressible, differentially rotating...... background threaded by a vertical magnetic field when disturbances with wavenumbers perpendicular to the shear are considered. We provide a geometrical description of these viscous, resistive MRI modes and show how their physical structure is modified as a function of the Reynolds and magnetic Reynolds...... momentum transport is always directed outwards. We also find that, for any combination of the Reynolds and magnetic Reynolds numbers, magnetic disturbances dominate both the energetics and the transport of angular momentum and that the total mean energy density is an upper bound for the total mean stress...

  20. Neuronal correlates of "free will" are associated with regional specialization in the human intrinsic/default network.

    Science.gov (United States)

    Goldberg, Ilan; Ullman, Shimon; Malach, Rafael

    2008-09-01

    Recently, we proposed a fundamental subdivision of the human cortex into two complementary networks-an "extrinsic" one which deals with the external environment, and an "intrinsic" one which largely overlaps with the "default mode" system, and deals with internally oriented and endogenous mental processes. Here we tested this hypothesis by contrasting decision making under external and internally-derived conditions. Subjects were presented with an external cue, and were required to either follow an external instruction ("determined" condition) or to ignore it and follow a voluntary decision process ("free-will" condition). Our results show that a well defined component of the intrinsic system-the right inferior parietal cortex-was preferentially activated during the "free-will" condition. Importantly, this activity was significantly higher than the base-line resting state. The results support a self-related role for the intrinsic system and provide clear evidence for both hemispheric and regional specialization in the human intrinsic system.

  1. Identifying the neural substrates of intrinsic motivation during task performance.

    Science.gov (United States)

    Lee, Woogul; Reeve, Johnmarshall

    2017-10-01

    Intrinsic motivation is the inherent tendency to seek out novelty and challenge, to explore and investigate, and to stretch and extend one's capacities. When people imagine performing intrinsically motivating tasks, they show heightened anterior insular cortex (AIC) activity. To fully explain the neural system of intrinsic motivation, however, requires assessing neural activity while people actually perform intrinsically motivating tasks (i.e., while answering curiosity-inducing questions or solving competence-enabling anagrams). Using event-related functional magnetic resonance imaging, we found that the neural system of intrinsic motivation involves not only AIC activity, but also striatum activity and, further, AIC-striatum functional interactions. These findings suggest that subjective feelings of intrinsic satisfaction (associated with AIC activations), reward processing (associated with striatum activations), and their interactions underlie the actual experience of intrinsic motivation. These neural findings are consistent with the conceptualization of intrinsic motivation as the pursuit and satisfaction of subjective feelings (interest and enjoyment) as intrinsic rewards.

  2. Proton-neutron modes in non-axial nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Leviatan, A. (Center for Theoretical Physics, Yale Univ., New Haven, CT (USA) Theoretical Div., Los Alamos National Lab., NM (USA)); Ginocchio, J.N. (Theoretical Div., Los Alamos National Lab., NM (USA))

    1991-09-05

    A normal-mode analysis is carried out for aligned rigid-triaxial, gamma-unstable and oblique proton-neutron shapes. Intrinsic hamiltonians, energy surfaces and estimates for bandhead energies and selected transition rates are provided. Possible experimental signatures are briefly discussed. (orig.).

  3. Proton-neutron modes in non-axial nuclei

    International Nuclear Information System (INIS)

    Leviatan, A.; Ginocchio, J.N.

    1991-01-01

    A normal-mode analysis is carried out for aligned rigid-triaxial, gamma-unstable and oblique proton-neutron shapes. Intrinsic hamiltonians, energy surfaces and estimates for bandhead energies and selected transition rates are provided. Possible experimental signatures are briefly discussed. (orig.)

  4. Measure of synchrony in the activity of intrinsic cardiac neurons

    International Nuclear Information System (INIS)

    Longpré, Jean-Philippe; Salavatian, Siamak; Jacquemet, Vincent; Beaumont, Eric; Armour, J Andrew; Ardell, Jeffrey L

    2014-01-01

    Recent multielectrode array recordings in ganglionated plexi of canine atria have opened the way to the study of population dynamics of intrinsic cardiac neurons. These data provide critical insights into the role of local processing that these ganglia play in the regulation of cardiac function. Low firing rates, marked non-stationarity, interplay with the cardiovascular and pulmonary systems and artifacts generated by myocardial activity create new constraints not present in brain recordings for which almost all neuronal analysis techniques have been developed. We adapted and extended the jitter-based synchrony index (SI) to (1) provide a robust and computationally efficient tool for assessing the level and statistical significance of SI between cardiac neurons, (2) estimate the bias on SI resulting from neuronal activity possibly hidden in myocardial artifacts, (3) quantify the synchrony or anti-synchrony between neuronal activity and the phase in the cardiac and respiratory cycles. The method was validated on firing time series from a total of 98 individual neurons identified in 8 dog experiments. SI ranged from −0.14 to 0.66, with 23 pairs of neurons with SI > 0.1. The estimated bias due to artifacts was typically <1%. Strongly cardiovascular- and pulmonary-related neurons (SI > 0.5) were found. Results support the use of jitter-based SI in the context of intrinsic cardiac neurons. (paper)

  5. Intrinsic Motivation in Open Source Software Development

    DEFF Research Database (Denmark)

    Bitzer, J.; W., Schrettl,; Schröder, Philipp

    2004-01-01

    This papers sheds light on the puzzling evidence that even though open source software (OSS) is a public good, it is developed for free by highly qualified, young and motivated individuals, and evolves at a rapid pace. We show that once OSS development is understood as the private provision...... of a public good, these features emerge quite naturally. We adapt a dynamic private-provision-of-public-goods model to reflects key aspects of the OSS phenomenon. In particular, instead of relying on extrinsic motives for programmers (e.g. signaling) the present model is driven by intrinsic motives of OSS...... programmers, such as user-programmers, play value or \\emph{homo ludens} payoff, and gift culture benefits. Such intrinsic motives feature extensively in the wider OSS literature and turn out to add new insights to the economic analysis....

  6. Does Aerobic Exercise Influence Intrinsic Brain Activity?

    DEFF Research Database (Denmark)

    Flodin, Pär; Jonasson, Lars S; Riklund, Katrin

    2017-01-01

    Previous studies have indicated that aerobic exercise could reduce age related decline in cognition and brain functioning. Here we investigated the effects of aerobic exercise on intrinsic brain activity. Sixty sedentary healthy males and females (64-78 years) were randomized into either an aerobic...... exercise group or an active control group. Both groups recieved supervised training, 3 days a week for 6 months. Multimodal brain imaging data was acquired before and after the intervention, including 10 min of resting state brain functional magnetic resonance imaging (rs-fMRI) and arterial spin labeling...... group improved more. Contrary to our hypothesis, we did not observe any significant group by time interactions with regard to any measure of intrinsic activity. To further probe putative relationships between fitness and brain activity, we performed post hoc analyses disregarding group belongings...

  7. Documentation Requirements, Intrinsic Motivation, and Worker Absence

    DEFF Research Database (Denmark)

    Andersen, Lotte Bøgh; Kristensen, Nicolai; Pedersen, Lene Holm

    2015-01-01

    Command systems are widely used to monitor public service provision, but little is known about unintended effects on individual workers’ motivation and work effort. Using insights from motivation crowding theory, we estimate a SEM model that captures how Danish childcare assistants and social...... and higher sickness absence. The association is statistically significant, but very small in substantive terms. The result is nevertheless consistent with the expectation in motivation crowding theory and contributes to the literature by including a new, reliable behavioral variable—sickness absence....../healthcare assistants perceive documentation requirements. We analyze how this perception relates to intrinsic motivation measured in a survey and sickness absence as reported in administrative registers, and find that individuals who perceive documentation requirements as controlling have lower intrinsic motivation...

  8. Extrinsic and intrinsic determinants of nerve regeneration

    Directory of Open Access Journals (Sweden)

    Toby A. Ferguson

    2011-01-01

    Full Text Available After central nervous system (CNS injury axons fail to regenerate often leading to persistent neurologic deficit although injured peripheral nervous system (PNS axons mount a robust regenerative response that may lead to functional recovery. Some of the failures of CNS regeneration arise from the many glial-based inhibitory molecules found in the injured CNS, whereas the intrinsic regenerative potential of some CNS neurons is actively curtailed during CNS maturation and limited after injury. In this review, the molecular basis for extrinsic and intrinsic modulation of axon regeneration within the nervous system is evaluated. A more complete understanding of the factors limiting axonal regeneration will provide a rational basis, which is used to develop improved treatments for nervous system injury.

  9. Tapping mode microwave impedance microscopy

    KAUST Repository

    Lai, K.

    2009-01-01

    We report tapping mode microwave impedance imaging based on atomic force microscope platforms. The shielded cantilever probe is critical to localize the tip-sample interaction near the tip apex. The modulated tip-sample impedance can be accurately simulated by the finite-element analysis and the result agrees quantitatively to the experimental data on a series of thin-film dielectric samples. The tapping mode microwave imaging is also superior to the contact mode in that the thermal drift in a long time scale is totally eliminated and an absolute measurement on the dielectric properties is possible. We demonstrated tapping images on working nanodevices, and the data are consistent with the transport results. © 2009 American Institute of Physics.

  10. Failure Modes of thin supported Membranes

    DEFF Research Database (Denmark)

    Hendriksen, Peter Vang; Høgsberg, J.R.; Kjeldsen, Ane Mette

    2007-01-01

    Four different failure modes relevant to tubular supported membranes (thin dense films on a thick porous support) were analyzed. The failure modes were: 1) Structural collapse due to external pressure 2) burst of locally unsupported areas, 3) formation of surface cracks in the membrane due to TEC......-mismatches, and finally 4) delamination between membrane and support due to expansion of the membrane on use. Design criteria to minimize risk of failure by the four different modes are discussed. The theoretical analysis of the two last failure modes is compared to failures observed on actual components....

  11. Intrinsic luminescence of alkali silicate glasses

    Energy Technology Data Exchange (ETDEWEB)

    Arbuzov, V.I.; Grabovskis, V.Y.; Tolstoi, M.N.; Vitol, I.K.

    1986-09-01

    This study obtains additional information on L centers and their role in electron excitation and intrinsic luminescence of a whole series. (Li, Na, K, Rb, and Cs) of alkali silicate glasses. The authors compare the features of the interaction with radiation of specimens of glass and crystal of a similar chemical composition, since silicates of alkali metals can be obtained in both the glassy and crystalline states.

  12. Intrinsic work motivation and pension reform acceptance

    OpenAIRE

    Heinemann, Friedrich; Hennighausen, Tanja; Moessinger, Marc-Daniel

    2011-01-01

    Although demographic change leaves pay-as-you-go pension systems unsustainable, reforms, such as a higher pension age, are highly unpopular. This contribution looks into the role of intrinsic motivation as a driver for pension reform acceptance. Theoretical reasoning suggests that this driver should be relevant: The choice among different pension reform options (increasing pension age, increasing contributions, cutting pensions) can be analyzed within the framework of an optimal job separatio...

  13. A structural model of intrinsic motivation

    OpenAIRE

    Aguilar, Javier; González, Daniel; Aguilar, Amira

    2017-01-01

    The main purpose of this research was to develop and test a structural model of intrinsic motivation among students of the University of Sonora to the curriculum of their careers. A secondary objective was to overcome the limitations of the model developed among students of the UNAM. Eight psychometric scales developed by the authors in previous studies were used, which showed satisfactory reliability and validity values. The model tested was similar to the sample of the UNAM, except for the ...

  14. H-mode physics

    International Nuclear Information System (INIS)

    Itoh, Sanae.

    1991-06-01

    After the discovery of the H-mode in ASDEX ( a tokamak in Germany ) the transition between the L-mode ( Low confinement mode ) and H-mode ( High confinement mode ) has been observed in many tokamaks in the world. The H-mode has made a breakthrough in improving the plasma parameters and has been recognized to be a universal phenomena. Since its discovery, the extensive studies both in experiments and in theory have been made. The research on H-mode has been casting new problems of an anomalous transport across the magnetic surface. This series of lectures will provide a brief review of experiments for explaining H-mode and a model theory of H-mode transition based on the electric field bifurcation. If the time is available, a new theoretical model of the temporal evolution of the H-mode will be given. (author)

  15. Moral Distress, Workplace Health, and Intrinsic Harm.

    Science.gov (United States)

    Weber, Elijah

    2016-05-01

    Moral distress is now being recognized as a frequent experience for many health care providers, and there's good evidence that it has a negative impact on the health care work environment. However, contemporary discussions of moral distress have several problems. First, they tend to rely on inadequate characterizations of moral distress. As a result, subsequent investigations regarding the frequency and consequences of moral distress often proceed without a clear understanding of the phenomenon being discussed, and thereby risk substantially misrepresenting the nature, frequency, and possible consequences of moral distress. These discussions also minimize the intrinsically harmful aspects of moral distress. This is a serious omission. Moral distress doesn't just have a negative impact on the health care work environment; it also directly harms the one who experiences it. In this paper, I claim that these problems can be addressed by first clarifying our understanding of moral distress, and then identifying what makes moral distress intrinsically harmful. I begin by identifying three common mistakes that characterizations of moral distress tend to make, and explaining why these mistakes are problematic. Next, I offer an account of moral distress that avoids these mistakes. Then, I defend the claim that moral distress is intrinsically harmful to the subject who experiences it. I conclude by explaining how acknowledging this aspect of moral distress should reshape our discussions about how best to deal with this phenomenon. © 2015 John Wiley & Sons Ltd.

  16. Intrinsic electron trapping in amorphous oxide

    Science.gov (United States)

    Strand, Jack; Kaviani, Moloud; Afanas’ev, Valeri V.; Lisoni, Judit G.; Shluger, Alexander L.

    2018-03-01

    We demonstrate that electron trapping at intrinsic precursor sites is endemic in non-glass-forming amorphous oxide films. The energy distributions of trapped electron states in ultra-pure prototype amorphous (a)-HfO2 insulator obtained from exhaustive photo-depopulation experiments demonstrate electron states in the energy range of 2–3 eV below the oxide conduction band. These energy distributions are compared to the results of density functional calculations of a-HfO2 models of realistic density. The experimental results can be explained by the presence of intrinsic charge trapping sites formed by under-coordinated Hf cations and elongated Hf–O bonds in a-HfO2. These charge trapping states can capture up to two electrons, forming polarons and bi-polarons. The corresponding trapping sites are different from the dangling-bond type defects responsible for trapping in glass-forming oxides, such as SiO2, in that the traps are formed without bonds being broken. Furthermore, introduction of hydrogen causes formation of somewhat energetically deeper electron traps when a proton is immobilized next to the trapped electron bi-polaron. The proposed novel mechanism of intrinsic charge trapping in a-HfO2 represents a new paradigm for charge trapping in a broad class of non-glass-forming amorphous insulators.

  17. Intrinsic functional network architecture of human semantic processing: Modules and hubs.

    Science.gov (United States)

    Xu, Yangwen; Lin, Qixiang; Han, Zaizhu; He, Yong; Bi, Yanchao

    2016-05-15

    Semantic processing entails the activation of widely distributed brain areas across the temporal, parietal, and frontal lobes. To understand the functional structure of this semantic system, we examined its intrinsic functional connectivity pattern using a database of 146 participants. Focusing on areas consistently activated during semantic processing generated from a meta-analysis of 120 neuroimaging studies (Binder et al., 2009), we found that these regions were organized into three stable modules corresponding to the default mode network (Module DMN), the left perisylvian network (Module PSN), and the left frontoparietal network (Module FPN). These three dissociable modules were integrated by multiple connector hubs-the left angular gyrus (AG) and the left superior/middle frontal gyrus linking all three modules, the left anterior temporal lobe linking Modules DMN and PSN, the left posterior portion of dorsal intraparietal sulcus (IPS) linking Modules DMN and FPN, and the left posterior middle temporal gyrus (MTG) linking Modules PSN and FPN. Provincial hubs, which converge local information within each system, were also identified: the bilateral posterior cingulate cortices/precuneus, the bilateral border area of the posterior AG and the superior lateral occipital gyrus for Module DMN; the left supramarginal gyrus, the middle part of the left MTG and the left orbital inferior frontal gyrus (IFG) for Module FPN; and the left triangular IFG and the left IPS for Module FPN. A neuro-functional model for semantic processing was derived based on these findings, incorporating the interactions of memory, language, and control. Copyright © 2016 Elsevier Inc. All rights reserved.

  18. Intrinsic oxygen fugacity measurements of some Allende Type B inclusions

    Science.gov (United States)

    Kozul, Jean M.; Hewins, Roger H.; Ulmer, Gene C.

    1988-01-01

    The intrinsic oxygen fugacities (IOFs) of two type B Ca-rich and Al-rich inclusions (CAI) from the Allende meteorite were measured using the solid-electrolyte double-cell IOF technique of Ulmer et al. (1976). The measurements were compared to calculated and experimentally extrapolated fO2 of type B phases. It was found that the IOFs of the type B are 6-8 orders of magnitude more oxidized (H2/H2O = 1-10) than the canonical solar nebular gas (H2/H2O = 100-2000). It is suggested that some local fO2 enhancing mechanism, such as dust or gas concentrations, or the release of oxygen-rich vapors during CAI volatilization in the type B inclusions was in operation at temperatures higher than 700 C.

  19. Managing employee motivation: Exploring the connections between managers' enforcement actions, employee perceptions, and employee intrinsic motivation

    DEFF Research Database (Denmark)

    Mikkelsen, Maria Falk; Jacobsen, Christian Bøtcher; Andersen, Lotte Bøgh

    2017-01-01

    A number of studies show that the use of external interventions, such as command systems and economic incentives, can decrease employee intrinsic motivation. Our knowledge of why the size of “the hidden cost of rewards” differs between organizations is, however, still sparse. In this paper, we...... analyze whether local managers—the primary enforcers of external interventions—affect how employees perceive a command system and thereby affect employee intrinsic motivation. Using a multilevel dataset of 1,190 teachers and 32 school principals, we test whether principals’ use of “hard”, “mixed” or “soft......, part of this association is mediated by teachers’ perceptions of the command. These findings support the motivation crowding argument that employee intrinsic motivation depend on the employees’ need for self-determination....

  20. Importance and challenges of measuring intrinsic foot muscle strength

    Science.gov (United States)

    2012-01-01

    Background Intrinsic foot muscle weakness has been implicated in a range of foot deformities and disorders. However, to establish a relationship between intrinsic muscle weakness and foot pathology, an objective measure of intrinsic muscle strength is needed. The aim of this review was to provide an overview of the anatomy and role of intrinsic foot muscles, implications of intrinsic weakness and evaluate the different methods used to measure intrinsic foot muscle strength. Method Literature was sourced from database searches of MEDLINE, PubMed, SCOPUS, Cochrane Library, PEDro and CINAHL up to June 2012. Results There is no widely accepted method of measuring intrinsic foot muscle strength. Methods to estimate toe flexor muscle strength include the paper grip test, plantar pressure, toe dynamometry, and the intrinsic positive test. Hand-held dynamometry has excellent interrater and intrarater reliability and limits toe curling, which is an action hypothesised to activate extrinsic toe flexor muscles. However, it is unclear whether any method can actually isolate intrinsic muscle strength. Also most methods measure only toe flexor strength and other actions such as toe extension and abduction have not been adequately assessed. Indirect methods to investigate intrinsic muscle structure and performance include CT, ultrasonography, MRI, EMG, and muscle biopsy. Indirect methods often discriminate between intrinsic and extrinsic muscles, but lack the ability to measure muscle force. Conclusions There are many challenges to accurately measure intrinsic muscle strength in isolation. Most studies have measured toe flexor strength as a surrogate measure of intrinsic muscle strength. Hand-held dynamometry appears to be a promising method of estimating intrinsic muscle strength. However, the contribution of extrinsic muscles cannot be excluded from toe flexor strength measurement. Future research should clarify the relative contribution of intrinsic and extrinsic muscles

  1. Positive consequences of intrinsically rewarding work: A model to ...

    African Journals Online (AJOL)

    This study sought to empirically test a theoretical model outlining the relationships between intrinsic rewards, intrinsic motivation, work engagement and intention to quit, in an attempt to empirically assess whether intrinsic rewards result in improved levels of motivation, engagement and retention. Using a sample of 587 ...

  2. The value of nature: Economic, intrinsic, or both?

    Science.gov (United States)

    There has been a long standing argument that ecosystems have intrinsic value and therefore there is no need to put a price tag on Mother Nature. The concept of intrinsic value reflects the perspective that nature has value in its own right, independent of human uses. Intrinsic va...

  3. Personalizing Sample Databases with Facebook Information to Increase Intrinsic Motivation

    Science.gov (United States)

    Marzo, Asier; Ardaiz, Oscar; Sanz de Acedo, María Teresa; Sanz de Acedo, María Luisa

    2017-01-01

    Motivation is fundamental for students to achieve successful and complete learning. Motivation can be extrinsic, i.e., driven by external rewards, or intrinsic, i.e., driven by internal factors. Intrinsic motivation is the most effective and must be inspired by the task at hand. Here, a novel strategy is presented to increase intrinsic motivation…

  4. Intrinsic Motivation: An Overlooked Component for Student Success

    Science.gov (United States)

    Augustyniak, Robert A.; Ables, Adrienne Z.; Guilford, Philip; Lujan, Heidi L.; Cortright, Ronald N.; DiCarlo, Stephen E.

    2016-01-01

    Intrinsic motivation to learn involves engaging in learning opportunities because they are seen as enjoyable, interesting, or relevant to meeting one's core psychological needs. As a result, intrinsic motivation is associated with high levels of effort and task performance. Students with greater levels of intrinsic motivation demonstrate strong…

  5. The Development of Intrinsic Motivation for Physical Activity

    Science.gov (United States)

    2005-07-01

    The Development of Intrinsic Motivation for Physical Activity by James Dunigan Beaty Bachelor of Science Central Washington...2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE The Development of Intrinsic Motivation for Physical Activity 5a. CONTRACT...Government." 3 ABSTRACT The Development of Intrinsic Motivation for Physical Activity by James Dunigan Beaty Cynthia Carruthers, Ph.D

  6. Elements of the Competitive Situation That Affect Intrinsic Motivation.

    Science.gov (United States)

    Reeve, Johnmarshall; Deci, Edward L.

    1996-01-01

    Explores the effects of three elements of the competitive situation (competitive set, competitive outcome, and interpersonal context) on intrinsic motivation in a sample of college students (n=100). Competitive outcome and interpersonal context affected intrinsic motivation: winning increased intrinsic motivation, while pressured interpersonal…

  7. Innate and intrinsic antiviral immunity in skin.

    Science.gov (United States)

    Kawamura, Tatsuyoshi; Ogawa, Youichi; Aoki, Rui; Shimada, Shinji

    2014-09-01

    As the body's most exposed interface with the environment, the skin is constantly challenged by potentially pathogenic microbes, including viruses. To sense the invading viruses, various types of cells resident in the skin express many different pattern-recognition receptors (PRRs) such as C-type lectin receptors (CLRs), Toll-like receptors (TLRs), nucleotide-binding oligomerization domain (NOD)-like receptors (NLRs), retinoic acid-inducible gene I (RIG-I)-like receptors (RLRs) and cytosolic DNA sensors, that can detect the pathogen-associated molecular patterns (PAMPs) of the viruses. The detection of viral PAMPs initiates two major innate immune signaling cascades: the first involves the activation of the downstream transcription factors, such as interferon regulatory factors (IRFs), nuclear factor kappa B (NF-κB) and activator protein 1 (AP-1), which cooperate to induce the transcription of type I interferons and pro-inflammatory cytokines. The second signaling pathway involves the caspase-1-mediated processing of IL-1β and IL-18 through the formation of an inflammasome complex. Cutaneous innate immunity including the production of the innate cytokines constitutes the first line of host defence that limits the virus dissemination from the skin, and also plays an important role in the activation of adaptive immune response, which represents the second line of defence. More recently, the third immunity "intrinsic immunity" has emerged, that provides an immediate and direct antiviral defense mediated by host intrinsic restriction factors. This review focuses on the recent advances regarding the antiviral immune systems, highlighting the innate and intrinsic immunity against the viral infections in the skin, and describes how viral components are recognized by cutaneous immune systems. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  8. Effects of scanner acoustic noise on intrinsic brain activity during auditory stimulation.

    Science.gov (United States)

    Yakunina, Natalia; Kang, Eun Kyoung; Kim, Tae Su; Min, Ji-Hoon; Kim, Sam Soo; Nam, Eui-Cheol

    2015-10-01

    Although the effects of scanner background noise (SBN) during functional magnetic resonance imaging (fMRI) have been extensively investigated for the brain regions involved in auditory processing, its impact on other types of intrinsic brain activity has largely been neglected. The present study evaluated the influence of SBN on a number of intrinsic connectivity networks (ICNs) during auditory stimulation by comparing the results obtained using sparse temporal acquisition (STA) with those using continuous acquisition (CA). Fourteen healthy subjects were presented with classical music pieces in a block paradigm during two sessions of STA and CA. A volume-matched CA dataset (CAm) was generated by subsampling the CA dataset to temporally match it with the STA data. Independent component analysis was performed on the concatenated STA-CAm datasets, and voxel data, time courses, power spectra, and functional connectivity were compared. The ICA revealed 19 ICNs; the auditory, default mode, salience, and frontoparietal networks showed greater activity in the STA. The spectral peaks in 17 networks corresponded to the stimulation cycles in the STA, while only five networks displayed this correspondence in the CA. The dorsal default mode and salience networks exhibited stronger correlations with the stimulus waveform in the STA. SBN appeared to influence not only the areas of auditory response but also the majority of other ICNs, including attention and sensory networks. Therefore, SBN should be regarded as a serious nuisance factor during fMRI studies investigating intrinsic brain activity under external stimulation or task loads.

  9. Effects of scanner acoustic noise on intrinsic brain activity during auditory stimulation

    Energy Technology Data Exchange (ETDEWEB)

    Yakunina, Natalia [Kangwon National University, Institute of Medical Science, School of Medicine, Chuncheon (Korea, Republic of); Kangwon National University Hospital, Neuroscience Research Institute, Chuncheon (Korea, Republic of); Kang, Eun Kyoung [Kangwon National University Hospital, Department of Rehabilitation Medicine, Chuncheon (Korea, Republic of); Kim, Tae Su [Kangwon National University Hospital, Department of Otolaryngology, Chuncheon (Korea, Republic of); Kangwon National University, School of Medicine, Department of Otolaryngology, Chuncheon (Korea, Republic of); Min, Ji-Hoon [University of Michigan, Department of Biopsychology, Cognition, and Neuroscience, Ann Arbor, MI (United States); Kim, Sam Soo [Kangwon National University Hospital, Neuroscience Research Institute, Chuncheon (Korea, Republic of); Kangwon National University, School of Medicine, Department of Radiology, Chuncheon (Korea, Republic of); Nam, Eui-Cheol [Kangwon National University Hospital, Neuroscience Research Institute, Chuncheon (Korea, Republic of); Kangwon National University, School of Medicine, Department of Otolaryngology, Chuncheon (Korea, Republic of)

    2015-10-15

    Although the effects of scanner background noise (SBN) during functional magnetic resonance imaging (fMRI) have been extensively investigated for the brain regions involved in auditory processing, its impact on other types of intrinsic brain activity has largely been neglected. The present study evaluated the influence of SBN on a number of intrinsic connectivity networks (ICNs) during auditory stimulation by comparing the results obtained using sparse temporal acquisition (STA) with those using continuous acquisition (CA). Fourteen healthy subjects were presented with classical music pieces in a block paradigm during two sessions of STA and CA. A volume-matched CA dataset (CAm) was generated by subsampling the CA dataset to temporally match it with the STA data. Independent component analysis was performed on the concatenated STA-CAm datasets, and voxel data, time courses, power spectra, and functional connectivity were compared. The ICA revealed 19 ICNs; the auditory, default mode, salience, and frontoparietal networks showed greater activity in the STA. The spectral peaks in 17 networks corresponded to the stimulation cycles in the STA, while only five networks displayed this correspondence in the CA. The dorsal default mode and salience networks exhibited stronger correlations with the stimulus waveform in the STA. SBN appeared to influence not only the areas of auditory response but also the majority of other ICNs, including attention and sensory networks. Therefore, SBN should be regarded as a serious nuisance factor during fMRI studies investigating intrinsic brain activity under external stimulation or task loads. (orig.)

  10. Effects of scanner acoustic noise on intrinsic brain activity during auditory stimulation

    International Nuclear Information System (INIS)

    Yakunina, Natalia; Kang, Eun Kyoung; Kim, Tae Su; Min, Ji-Hoon; Kim, Sam Soo; Nam, Eui-Cheol

    2015-01-01

    Although the effects of scanner background noise (SBN) during functional magnetic resonance imaging (fMRI) have been extensively investigated for the brain regions involved in auditory processing, its impact on other types of intrinsic brain activity has largely been neglected. The present study evaluated the influence of SBN on a number of intrinsic connectivity networks (ICNs) during auditory stimulation by comparing the results obtained using sparse temporal acquisition (STA) with those using continuous acquisition (CA). Fourteen healthy subjects were presented with classical music pieces in a block paradigm during two sessions of STA and CA. A volume-matched CA dataset (CAm) was generated by subsampling the CA dataset to temporally match it with the STA data. Independent component analysis was performed on the concatenated STA-CAm datasets, and voxel data, time courses, power spectra, and functional connectivity were compared. The ICA revealed 19 ICNs; the auditory, default mode, salience, and frontoparietal networks showed greater activity in the STA. The spectral peaks in 17 networks corresponded to the stimulation cycles in the STA, while only five networks displayed this correspondence in the CA. The dorsal default mode and salience networks exhibited stronger correlations with the stimulus waveform in the STA. SBN appeared to influence not only the areas of auditory response but also the majority of other ICNs, including attention and sensory networks. Therefore, SBN should be regarded as a serious nuisance factor during fMRI studies investigating intrinsic brain activity under external stimulation or task loads. (orig.)

  11. Metacognitive mastery and intrinsic motivation in schizophrenia.

    Science.gov (United States)

    Vohs, Jenifer L; Lysaker, Paul H

    2014-01-01

    Deficits in intrinsic motivation (IM) have been linked to poorer outcome in schizophrenia, but its proximal mechanisms remain poorly understood. This study examined whether metacognitive mastery, or the capacity to use knowledge of self, others, and context to identify and cope with psychological difficulties, predicted levels of IM for 6 months among 75 participants with prolonged schizophrenia. Repeated-measures analysis of variance revealed that high metacognitive mastery predicted consistently higher levels of IM; however, intermediate and low mastery did not produce unique IM profiles. The findings suggest that metacognitive mastery may have an important role in IM over time and could be a meaningful treatment target.

  12. Symplectic Structure of Intrinsic Time Gravity

    Directory of Open Access Journals (Sweden)

    Eyo Eyo Ita

    2016-08-01

    Full Text Available The Poisson structure of intrinsic time gravity is analysed. With the starting point comprising a unimodular three-metric with traceless momentum, a trace-induced anomaly results upon quantization. This leads to a revision of the choice of momentum variable to the (mixed index traceless momentric. This latter choice unitarily implements the fundamental commutation relations, which now take on the form of an affine algebra with SU(3 Lie algebra amongst the momentric variables. The resulting relations unitarily implement tracelessness upon quantization. The associated Poisson brackets and Hamiltonian dynamics are studied.

  13. Intrinsically conductive polymer thin film piezoresistors

    DEFF Research Database (Denmark)

    Lillemose, Michael; Spieser, Martin; Christiansen, N.O.

    2008-01-01

    We report on the piezoresistive effect in the intrinsically conductive polymer, polyaniline. A process recipe for indirect patterning of thin film polyaniline has been developed. Using a specially designed chip, the polyaniline thin films have been characterised with respect to resistivity...... and strain sensitivity using two- and four-point measurement method. We have found that polyaniline has a negative gauge factor of K = -4.9, which makes it a candidate for piezoresistive read-out in polymer based MEMS-devices. (C) 2007 Elsevier B.V. All rights reserved....

  14. Intrinsic chirp of single-cycle pulses

    International Nuclear Information System (INIS)

    Lin Qiang; Zheng Jian; Dai Jianming; Ho, I-Chen; Zhang, X.-C.

    2010-01-01

    The Fourier transform-limited electromagnetic pulse has been regarded to be free of chirps for a long time. This is no longer true if the pulse duration goes down to or less than one optical cycle. We report the experimental observation of intrinsic chirps in such pulses with the sub-single-cycle terahertz (THz) waveforms obtained with a standard THz time-domain spectroscopy system. The results confirm the break down of the carrier-envelope (CE) expression for single-cycle optical pulses, and may influence the experimental measurements and theoretical modeling with single-cycle pulses.

  15. SNV's modes of ordering

    NARCIS (Netherlands)

    Hummel, John; Duim, van der Rene

    2016-01-01

    This article adopts an aidnographic approach to examine how internal organizational modes of ordering have influenced tourism development practices of SNV Netherlands Development Organisation (SNV). Our research revealed six modes of ordering: administration, project management, enterprising,

  16. Empirical mode decomposition for analyzing acoustical signals

    Science.gov (United States)

    Huang, Norden E. (Inventor)

    2005-01-01

    The present invention discloses a computer implemented signal analysis method through the Hilbert-Huang Transformation (HHT) for analyzing acoustical signals, which are assumed to be nonlinear and nonstationary. The Empirical Decomposition Method (EMD) and the Hilbert Spectral Analysis (HSA) are used to obtain the HHT. Essentially, the acoustical signal will be decomposed into the Intrinsic Mode Function Components (IMFs). Once the invention decomposes the acoustic signal into its constituting components, all operations such as analyzing, identifying, and removing unwanted signals can be performed on these components. Upon transforming the IMFs into Hilbert spectrum, the acoustical signal may be compared with other acoustical signals.

  17. Burst-Mode Asynchronous Controllers on FPGA

    Directory of Open Access Journals (Sweden)

    Duarte L. Oliveira

    2008-01-01

    Full Text Available FPGAs have been mainly used to design synchronous circuits. Asynchronous design on FPGAs is difficult because the resulting circuit may suffer from hazard problems. We propose a method that implements a popular class of asynchronous circuits, known as burst mode, on FPGAs based on look-up table architectures. We present two conditions that, if satisfied, guarantee essential hazard-free implementation on any LUT-based FPGA. By doing that, besides all the intrinsic advantages of asynchronous over synchronous circuits, they also take advantage of the shorter design time and lower cost associated with FPGA designs.

  18. Modes of log gravity

    NARCIS (Netherlands)

    Bergshoeff, Eric A.; Hohm, Olaf; Rosseel, Jan; Townsend, Paul K.

    2011-01-01

    The physical modes of a recently proposed D-dimensional "critical gravity'', linearized about its anti-de Sitter vacuum, are investigated. All "log mode'' solutions, which we categorize as "spin-2'' or "Proca'', arise as limits of the massive spin-2 modes of the noncritical theory. The linearized

  19. The Neglected Intrinsic Resistome of Bacterial Pathogens

    Science.gov (United States)

    Fajardo, Alicia; Martínez-Martín, Nadia; Mercadillo, María; Galán, Juan C.; Ghysels, Bart; Matthijs, Sandra; Cornelis, Pierre; Wiehlmann, Lutz; Tümmler, Burkhard; Baquero, Fernando; Martínez, José L.

    2008-01-01

    Bacteria with intrinsic resistance to antibiotics are a worrisome health problem. It is widely believed that intrinsic antibiotic resistance of bacterial pathogens is mainly the consequence of cellular impermeability and activity of efflux pumps. However, the analysis of transposon-tagged Pseudomonas aeruginosa mutants presented in this article shows that this phenotype emerges from the action of numerous proteins from all functional categories. Mutations in some genes make P. aeruginosa more susceptible to antibiotics and thereby represent new targets. Mutations in other genes make P. aeruginosa more resistant and therefore define novel mechanisms for mutation-driven acquisition of antibiotic resistance, opening a new research field based in the prediction of resistance before it emerges in clinical environments. Antibiotics are not just weapons against bacterial competitors, but also natural signalling molecules. Our results demonstrate that antibiotic resistance genes are not merely protective shields and offer a more comprehensive view of the role of antibiotic resistance genes in the clinic and in nature. PMID:18286176

  20. A tonoplast intrinsic protein in Gardenia jasminoides

    Science.gov (United States)

    Gao, Lan; Li, Hao-Ming

    2017-08-01

    Physiological and molecular studies proved that plasma membrane intrinsic proteins (PIPs) and tonoplast intrinsic proteins (TIPs) subfamily of aquaporins play key functions in plant water homeostasis. Five specialized subgroups (TIP1-5) of TIPs have been found in higher plants, in which the TIP1 and TIP2 isoforms are the largest arbitrary groups. TIPs have high water-transport activity than PIPs, some TIPs can transport other small molecule such as urea, ammonia, hydrogen peroxide, and carbon dioxide. In this work, the structure of the putative tonoplast aquaporin from Gardenia jasminoides (GjTIP) was analyzed. Its transcript level has increased during fruit maturation. A phylogenetic analysis indicates that the protein belongs to TIP1 subfamily. A three-dimensional model structure of GjTIP was built based on crystal structure of an ammonia-permeable AtTIP2-1 from Arabidopsis thaliana. The model structure displayed as a homo-tetramer, each monomer has six trans-membrane and two half-membrane-spanning α helices. The data suggests that the GjTIP has tendency to be a mixed function aquaporin, might involve in water, urea and hydrogen peroxide transport, and the gating machanism founded in some AQPs involving pH and phosphorylation response have not been proved in GjTIP.

  1. The neglected intrinsic resistome of bacterial pathogens.

    Directory of Open Access Journals (Sweden)

    Alicia Fajardo

    Full Text Available Bacteria with intrinsic resistance to antibiotics are a worrisome health problem. It is widely believed that intrinsic antibiotic resistance of bacterial pathogens is mainly the consequence of cellular impermeability and activity of efflux pumps. However, the analysis of transposon-tagged Pseudomonas aeruginosa mutants presented in this article shows that this phenotype emerges from the action of numerous proteins from all functional categories. Mutations in some genes make P. aeruginosa more susceptible to antibiotics and thereby represent new targets. Mutations in other genes make P. aeruginosa more resistant and therefore define novel mechanisms for mutation-driven acquisition of antibiotic resistance, opening a new research field based in the prediction of resistance before it emerges in clinical environments. Antibiotics are not just weapons against bacterial competitors, but also natural signalling molecules. Our results demonstrate that antibiotic resistance genes are not merely protective shields and offer a more comprehensive view of the role of antibiotic resistance genes in the clinic and in nature.

  2. Intrinsic terminators in Mycoplasma hyopneumoniae transcription.

    Science.gov (United States)

    Fritsch, Tiago Ebert; Siqueira, Franciele Maboni; Schrank, Irene Silveira

    2015-04-08

    Mycoplasma hyopneumoniae, an important pathogen of swine, exhibits a low guanine and cytosine (GC) content genome. M. hyopneumoniae genome is organised in long transcriptional units and promoter sequences have been mapped upstream of all transcription units. These analysis provided insights into the gene organisation and transcription initiation at the genome scale. However, the presence of transcriptional terminator sequences in the M. hyopneumoniae genome is poorly understood. In silico analyses demonstrated the presence of putative terminators in 82% of the 33 monocistronic units (mCs) and in 74% of the 116 polycistronic units (pCs) considering different classes of terminators. The functional activity of 23 intrinsic terminators was confirmed by RT-PCR and qPCR. Analysis of all terminators found by three software algorithms, combined with experimental results, allowed us to propose a pattern of RNA hairpin formation during the termination process and to predict the location of terminators in the M. hyopneumoniae genome sequence. The stem-loop structures of intrinsic terminators of mycoplasma diverge from the pattern of terminators found in other bacteria due the low content of guanine and cytosine. In M. hyopneumoniae, transcription can end after a transcriptional unit and before its terminator sequence and can also continue past the terminator sequence with RNA polymerases gradually releasing the RNA.

  3. Intrinsically disordered proteins drive membrane curvature.

    Science.gov (United States)

    Busch, David J; Houser, Justin R; Hayden, Carl C; Sherman, Michael B; Lafer, Eileen M; Stachowiak, Jeanne C

    2015-07-24

    Assembly of highly curved membrane structures is essential to cellular physiology. The prevailing view has been that proteins with curvature-promoting structural motifs, such as wedge-like amphipathic helices and crescent-shaped BAR domains, are required for bending membranes. Here we report that intrinsically disordered domains of the endocytic adaptor proteins, Epsin1 and AP180 are highly potent drivers of membrane curvature. This result is unexpected since intrinsically disordered domains lack a well-defined three-dimensional structure. However, in vitro measurements of membrane curvature and protein diffusivity demonstrate that the large hydrodynamic radii of these domains generate steric pressure that drives membrane bending. When disordered adaptor domains are expressed as transmembrane cargo in mammalian cells, they are excluded from clathrin-coated pits. We propose that a balance of steric pressure on the two surfaces of the membrane drives this exclusion. These results provide quantitative evidence for the influence of steric pressure on the content and assembly of curved cellular membrane structures.

  4. Intrinsic gray-matter connectivity of the brain in adults with autism spectrum disorder

    Science.gov (United States)

    Ecker, Christine; Ronan, Lisa; Feng, Yue; Daly, Eileen; Murphy, Clodagh; Ginestet, Cedric E.; Brammer, Michael; Fletcher, Paul C.; Bullmore, Edward T.; Suckling, John; Baron-Cohen, Simon; Williams, Steve; Loth, Eva; Murphy, Declan G. M.; Bailey, A. J.; Baron-Cohen, S.; Bolton, P. F.; Bullmore, E. T.; Carrington, S.; Chakrabarti, B.; Daly, E. M.; Deoni, S. C.; Ecker, C.; Happe, F.; Henty, J.; Jezzard, P.; Johnston, P.; Jones, D. K.; Lai, M. C.; Lombardo, M. V.; Madden, A.; Mullins, D.; Murphy, C. M.; Murphy, D. G.; Pasco, G.; Sadek, S.; Spain, D.; Steward, R.; Suckling, J.; Wheelwright, S.; Williams, S. C.

    2013-01-01

    Autism spectrum disorders (ASD) are a group of neurodevelopmental conditions that are accompanied by atypical brain connectivity. So far, in vivo evidence for atypical structural brain connectivity in ASD has mainly been based on neuroimaging studies of cortical white matter. However, genetic studies suggest that abnormal connectivity in ASD may also affect neural connections within the cortical gray matter. Such intrinsic gray-matter connections are inherently more difficult to describe in vivo but may be inferred from a variety of surface-based geometric features that can be measured using magnetic resonance imaging. Here, we present a neuroimaging study that examines the intrinsic cortico-cortical connectivity of the brain in ASD using measures of “cortical separation distances” to assess the global and local intrinsic “wiring costs” of the cortex (i.e., estimated length of horizontal connections required to wire the cortex within the cortical sheet). In a sample of 68 adults with ASD and matched controls, we observed significantly reduced intrinsic wiring costs of cortex in ASD, both globally and locally. Differences in global and local wiring cost were predominantly observed in fronto-temporal regions and also significantly predicted the severity of social and repetitive symptoms (respectively). Our study confirms that atypical cortico-cortical “connectivity” in ASD is not restricted to the development of white-matter connections but may also affect the intrinsic gray-matter architecture (and connectivity) within the cortical sheet. Thus, the atypical connectivity of the brain in ASD is complex, affecting both gray and white matter, and forms part of the core neural substrates underlying autistic symptoms. PMID:23878213

  5. Intrinsically secure fast reactors with dense cores

    International Nuclear Information System (INIS)

    Slessarev, Igor

    2007-01-01

    Secure safety, resistance to weapons material proliferation and problems of long-lived wastes remain the most important 'painful points' of nuclear power. Many innovative reactor concepts have been developed aimed at a radical enhancement of safety. The promising potential of innovative nuclear reactors allows for shifting accents in current reactor safety 'strategy' to reveal this worth. Such strategy is elaborated focusing on the priority for intrinsically secure safety features as well as on sure protection being provided by the first barrier of defence. Concerning the potential of fast reactors (i.e. sodium cooled, lead-cooled, etc.), there are no doubts that they are able to possess many favourable intrinsically secure safety features and to lay the proper foundation for a new reactor generation. However, some of their neutronic characteristics have to be radically improved. Among intrinsically secure safety properties, the following core parameters are significantly important: reactivity margin values, reactivity feed-back and coolant void effects. Ways of designing intrinsically secure safety features in fast reactors (titled hereafter as Intrinsically Secure Fast Reactors - ISFR) can be found in the frame of current reactor technologies by radical enhancement of core neutron economy and by optimization of core compositions. Simultaneously, respecting resistance to proliferation, by using non-enriched fuel feed as well as a core breeding gain close to zero, are considered as the important features (long-lived waste problems will be considered in a separate paper). This implies using the following reactor design options as well as closed fuel cycles with natural U as the reactor feed: ·Ultra-plate 'dense cores' of the ordinary (monolithic) type with negative total coolant void effects. ·Modular type cores. Multiple dense modules can be embedded in the common reflector for achieving the desired NPP total power. The modules can be used also independently (as

  6. The Neuroscience of Growth Mindset and Intrinsic Motivation.

    Science.gov (United States)

    Ng, Betsy

    2018-01-26

    Our actions can be triggered by intentions, incentives or intrinsic values. Recent neuroscientific research has yielded some results about the growth mindset and intrinsic motivation. With the advances in neuroscience and motivational studies, there is a global need to utilize this information to inform educational practice and research. Yet, little is known about the neuroscientific interplay between growth mindset and intrinsic motivation. This paper attempts to draw on the theories of growth mindset and intrinsic motivation, together with contemporary ideas in neuroscience, outline the potential for neuroscientific research in education. It aims to shed light on the relationship between growth mindset and intrinsic motivation in terms of supporting a growth mindset to facilitate intrinsic motivation through neural responses. Recent empirical research from the educational neuroscience perspective that provides insights into the interplay between growth mindset and intrinsic motivation will also be discussed.

  7. Health monitoring of pipeline girth weld using empirical mode decomposition

    Science.gov (United States)

    Rezaei, Davood; Taheri, Farid

    2010-05-01

    In the present paper the Hilbert-Huang transform (HHT), as a time-series analysis technique, has been combined with a local diagnostic approach in an effort to identify flaws in pipeline girth welds. This method is based on monitoring the free vibration signals of the pipe at its healthy and flawed states, and processing the signals through the HHT and its associated signal decomposition technique, known as empirical mode decomposition (EMD). The EMD method decomposes the vibration signals into a collection of intrinsic mode functions (IMFs). The deviations in structural integrity, measured from a healthy-state baseline, are subsequently evaluated by two damage sensitive parameters. The first is a damage index, referred to as the EM-EDI, which is established based on an energy comparison of the first or second IMF of the vibration signals, before and after occurrence of damage. The second parameter is the evaluation of the lag in instantaneous phase, a quantity derived from the HHT. In the developed methodologies, the pipe's free vibration is monitored by piezoceramic sensors and a laser Doppler vibrometer. The effectiveness of the proposed techniques is demonstrated through a set of numerical and experimental studies on a steel pipe with a mid-span girth weld, for both pressurized and nonpressurized conditions. To simulate a crack, a narrow notch is cut on one side of the girth weld. Several damage scenarios, including notches of different depths and at various locations on the pipe, are investigated. Results from both numerical and experimental studies reveal that in all damage cases the sensor located at the notch vicinity could successfully detect the notch and qualitatively predict its severity. The effect of internal pressure on the damage identification method is also monitored. Overall, the results are encouraging and promise the effectiveness of the proposed approaches as inexpensive systems for structural health monitoring purposes.

  8. Characterization of intrinsic and induced lateral conduction in space dielectric materials

    International Nuclear Information System (INIS)

    Hanna, R.; Paulmier, T.; Belhaj, M.; Dirassen, B.; Payan, D.; Balcon, N.

    2014-01-01

    Characterization of lateral charge carrier conduction in space dielectrics is of high importance for the prediction of charging behavior and electrostatic discharges on satellites. In the present paper, a new experimental approach for the analysis of surface conduction, which is not well understood and characterized in the literature, is established and discussed. Though this method, based on the use of two Kelvin probes, we have been able to discriminate between lateral and bulk charge transports and to reveal the presence of an intrinsic lateral conductivity on Teflon ® FEP irradiated with low energy electron beam. We demonstrated that lateral intrinsic conductivity is enhanced when incident current density increases and when approaching the sample surface. The experimental results are analyzed through trapping/detrapping and hopping models. Depending on radiation configuration mode, we have revealed as well the presence of a lateral conductivity that is enhanced by radiation ionization processes, and explained as well with a trapping/recombination model

  9. Resistive mode in rotating plasma columns including the hall current

    International Nuclear Information System (INIS)

    Galvao, R.M.O.

    1983-01-01

    A new resistive mode is shown to exist in rotating plasma columns. The mode is localized in the neighbourhood of the radius where the angular velocity of the bulk plasma is equal to minus half the local angular velocity of the ions. This singular point is caused by the Hall term in the generalized Ohm law. The growth rate of the mode scales with eta sup(1/2), where eta is the plasma resistivity. (Author) [pt

  10. Mode selection laser

    DEFF Research Database (Denmark)

    2014-01-01

    The invention relates to a semiconductor mode selection laser, particularly to a VCSEL laser (200) having mode selection properties. The mode selection capability of the laser is achieved by configuring one of the reflectors (15,51) in the resonance cavity so that a reflectivity of the reflector...... (15) varies spatially in one dimension or two dimensions. Accordingly, the reflector (15) with spatially varying reflectivity is part both of the resonance cavity and the mode selection functionality of the laser. A plurality of the lasers configured with different mode selectors, i.e. different...... spatial reflector variations, may be combined to generate a laser beam containing a plurality of orthogonal modes. The laser beam may be injected into a few- mode optical fiber, e.g. for the purpose of optical communication. The VCSEL may have intra-cavity contacts (31,37) and a Tunnel junction (33...

  11. Impurity modes in the one-dimensional XXZ Heisenberg model

    International Nuclear Information System (INIS)

    Sousa, J.M.; Leite, R.V.; Landim, R.R.; Costa Filho, R.N.

    2014-01-01

    A Green's function formalism is used to calculate the energy of impurity modes associated with one and/or two magnetic impurities in the one-dimensional Heisenberg XXZ magnetic chain. The system can be tuned from the Heisenberg to the Ising model varying a parameter λ. A numerical study is performed showing two types of localized modes (s and p). The modes depend on λ and the degeneracy of the acoustic modes is broken.

  12. Empirical mode decomposition improves detection of SSVEP.

    Science.gov (United States)

    Huang, Liya; Huang, Xiaoxia; Wang, Yu-Te; Wang, Yijun; Jung, Tzyy-Ping; Cheng, Chung-Kuan

    2013-01-01

    Steady State Visual Evoked Potentials (SSVEPs) have been used to quantify attention-related neural activity to visual targets. This study investigates how empirical mode decomposition (EMD) can improve detection accuracy and rate of SSVEPs. First, the scalp-recorded electroencephalogram (EEG) signals are decomposed into intrinsic mode functions (IMFs) by EMD. Then, IMF components accounting for SSVEPs are selected for target frequency detection. Finally, target frequency is identified by two methods: Gabor transform and Canonical Correlation Analysis (CCA). This study quantitatively explores the impact of EMD on the target frequency detection. Empirical results show that the EMD improves their recognition accuracy when Gabor transform is used, even in a shorter Gaussian window, but has little effects on the performance of the CCA. Further, this study finds that harmonic responses of the target frequency can be used to enhance the SSVEP detection both for the Gabor transform and CCA.

  13. Quantum synchronization effects in intrinsic Josephson junctions

    International Nuclear Information System (INIS)

    Machida, M.; Kano, T.; Yamada, S.; Okumura, M.; Imamura, T.; Koyama, T.

    2008-01-01

    We investigate quantum dynamics of the superconducting phase in intrinsic Josephson junctions of layered high-T c superconductors motivated by a recent experimental observation for the switching rate enhancement in the low temperature quantum regime. We pay attention to only the capacitive coupling between neighboring junctions and perform large-scale simulations for the Schroedinger equation derived from the Hamiltonian considering the capacitive coupling alone. The simulation focuses on an issue whether the switching of a junction induces those of the other junctions or not. The results reveal that the superconducting phase dynamics show synchronous behavior with increasing the quantum character, e.g., decreasing the junction plane area and effectively the temperature. This is qualitatively consistent with the experimental result

  14. Intrinsic thermal expansion of crystal defects

    International Nuclear Information System (INIS)

    Ganne, J.-P.

    1981-02-01

    Although the phenomenon of thermal expansion has long been known, the intrinsic thermal expansion coefficient (ITEC) βsub(d) of a point defect, derived from its formation volume vsub(d), has never been measured directly. The differential dilatometer by interferometry built by ASTY and GILDER is described. It has allowed βsub(d) to be measured for several defects. Vacancies and small interstitial loops were produced in aluminium by low temperature (20 K) fast neutron irradiation followed by an anneal up to the beginning of stage III (160 K). The very high value of the measured ratio βsub(d)/β 0 (12+-4) is comparable with a lattice statics calculated (42) value (11.5 0 [fr

  15. Intrinsic topological superfluidity - fluctuations and response

    Science.gov (United States)

    Levin, K.; Wu, Chien-Te; Anderson, Brandon; Boyack, Rufus

    Recent interest in topological superconductivity is based primarily on exploiting proximity effects to obtain this important phase. However, in cold gases it is possible to contemplate ``intrinsic'' topological superfluidity produced with a synthetic spin-orbit coupling and Zeeman field. It is important for such future experiments to establish how low in temperature one needs to go to reach the ordered phase. Similarly, it will be helpful to have a probe of the normal (pseudogap) phase to determine if the ultimate superfluid order will be topological or trivial. In this talk, we address these issues by considering fluctuation effects in such a superfluid, and calculate the critical transition temperature and response functions. We see qualitative signatures of topological superfluidity in spin and charge response functions. We also explore the suppression of superfluidity due to fluctuations, and importantly find that the temperature scales necessary to reach topological superfluidity are reasonably accessible

  16. Major Intrinsic Proteins in Biomimetic Membranes

    DEFF Research Database (Denmark)

    Helix Nielsen, Claus

    2010-01-01

    will generally have finite permeabilities to both electrolytes and non-electrolytes. The feasibility of a biomimetic MIP device thus depends on the relative transport contribution from both protein and biomimetic support matrix. Also the biomimetic matrix must be encapsulated in order to protect it and make....../separation technology, a unique class of membrane transport proteins is especially interesting the major intrinsic proteins (MIPs). Generally, MIPs conduct water molecules and selected solutes in and out of the cell while preventing the passage of other solutes, a property critical for the conservation of the cells...... it sufficiently stable in a final application. Here, I specifically discuss the feasibility of developing osmotic biomimetic MIP membranes, but the technical issues are of general concern in the design of biomimetic membranes capable of supporting selective transmembrane fluxes....

  17. Intrinsic densitometry: In-plant evaluation

    International Nuclear Information System (INIS)

    Nishida, K.; Kurosawa, A.; Masui, J.; Hsue, S.T.

    1994-11-01

    A measurement of the plutonium concentration in a sample is always necessary for nuclear material control and accounting. This report describes the testing of the intrinsic densitometry (ID) technique for implant applications. The authors found that the ID method can determine the plutonium concentrations to between 2 and 3% at concentrations of 100 g/l to 200 g/l with quartz cells and a measurement time of 3600 s. The precision can be improved to 1 to 2% with a higher counting rate. The authors also found that nitric acid concentration and the impurity level of uranium in the product plutonium solution do not affect the concentration measurement. When this technique is applied to plutonium solutions in stainless steel pipes, they found that similar precision in plutonium concentration can be achieved using a high-count-rate detector. The precision, however, is reduced with aged plutonium solutions

  18. On the intrinsic colours of cepheids

    International Nuclear Information System (INIS)

    Efremov, Yu.N.

    1979-01-01

    Some consequences from new data on the photometrically obtained intrinsic colours are considered. It is shown that the small amplitude and almost sinusoidal light-curve cepheids (Cs-subtype) increase their pulsation amplitude towards the red instability strip edge, differing from the other galactic cepheids. This feature is discussed in connection with Efremov's (1968) hypothesis that the Cs-cepheids first cross the instability strip from left to right. The galactic cepheid period-colour relation obtained by Dean, Warren and Cousins (1978) satisfies rather well the LMC cepheid observations and, consequently, considerations for the period-luminosity relations are made. The residuals from the PL relation proposed by us correlate with the colour residuals from the DWC period-colour relation ΔV/delta(B-V) being equal to 2.7. The luminosity effect as a possible cause of the discrepancy between the spectroscopic cepheid colours and the photometric colours is briefly discussed. (Auth.)

  19. Intrinsic Dynamics of Quantum-Dash Lasers

    KAUST Repository

    Chen, Cheng

    2011-10-01

    Temperature-dependent intrinsic modulation response of InAs/InAlGaAs quantum-dash lasers was investigated by using pulse optical injection modulation to minimize the effects of parasitics and self-heating. Compared to typical quantum-well lasers, the quantum-dash lasers were found to have comparable differential gain but approximately twice the gain compression factor, probably due to carrier heating by free-carrier absorption, as opposed to stimulated transition. Therefore, the narrower modulation bandwidth of the quantum-dash lasers than that of quantum-well lasers was attributed to their higher gain compression factor. In addition, as expected, quantum-dash lasers with relatively long and uniform dashes exhibit higher temperature stability than quantum-well lasers. However, the lasers with relatively short and nonuniform dashes exhibit stronger temperature dependence, probably due to their higher surface-to-volume ratio and nonuniform dash sizes. © 2011 IEEE.

  20. Intrinsic thermoelectric power of group VB metals

    Directory of Open Access Journals (Sweden)

    Gunadhor Singh Okram

    2012-03-01

    Full Text Available We have reinvestigated the thermopower of group VB metals in polycrystalline forms in the temperature range of 6-300K, taking into account the critical nature of the sample surface and heat treatment especially for niobium. Strikingly small magnitude, negative sign, phonon drag dip and superconductivity not reported previously were observed in surface-cleaned single crystalline Nb. However, while thermopower magnitudes are small, mixed signs were found in the polycrystalline V, Nb and Ta samples. These properties were therefore interpreted as their intrinsic properties and were briefly discussed taking into account of the existing theory by fitting also the data that give the Fermi energies of 10.94 eV, 5.08 eV and 1.86eV, respectively.

  1. Computer Simulations of Intrinsically Disordered Proteins

    Science.gov (United States)

    Chong, Song-Ho; Chatterjee, Prathit; Ham, Sihyun

    2017-05-01

    The investigation of intrinsically disordered proteins (IDPs) is a new frontier in structural and molecular biology that requires a new paradigm to connect structural disorder to function. Molecular dynamics simulations and statistical thermodynamics potentially offer ideal tools for atomic-level characterizations and thermodynamic descriptions of this fascinating class of proteins that will complement experimental studies. However, IDPs display sensitivity to inaccuracies in the underlying molecular mechanics force fields. Thus, achieving an accurate structural characterization of IDPs via simulations is a challenge. It is also daunting to perform a configuration-space integration over heterogeneous structural ensembles sampled by IDPs to extract, in particular, protein configurational entropy. In this review, we summarize recent efforts devoted to the development of force fields and the critical evaluations of their performance when applied to IDPs. We also survey recent advances in computational methods for protein configurational entropy that aim to provide a thermodynamic link between structural disorder and protein activity.

  2. IMPACT OF BARYONIC PHYSICS ON INTRINSIC ALIGNMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Tenneti, Ananth; Gnedin, Nickolay Y. [Particle Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Feng, Yu, E-mail: vat@andrew.cmu.edu [Berkeley Center for Cosmological Physics, Department of Physics, University of California Berkeley, Berkeley, CA 94720 (United States)

    2017-01-10

    We explore the effects of specific assumptions in the subgrid models of star formation and stellar and active galactic nucleus feedback on intrinsic alignments of galaxies in cosmological simulations of the “MassiveBlack-II” family. Using smaller-volume simulations, we explore the parameter space of the subgrid star formation and feedback model and find remarkable robustness of the observable statistical measures to the details of subgrid physics. The one observational probe most sensitive to modeling details is the distribution of misalignment angles. We hypothesize that the amount of angular momentum carried away by the galactic wind is the primary physical quantity that controls the orientation of the stellar distribution. Our results are also consistent with a similar study by the EAGLE simulation team.

  3. A new approach for crude oil price analysis based on empirical mode decomposition

    International Nuclear Information System (INIS)

    The importance of understanding the underlying characteristics of international crude oil price movements attracts much attention from academic researchers and business practitioners. Due to the intrinsic complexity of the oil market, however, most of them fail to produce consistently good results. Empirical Mode Decomposition (EMD), recently proposed by Huang et al., appears to be a novel data analysis method for nonlinear and non-stationary time series. By decomposing a time series into a small number of independent and concretely implicational intrinsic modes based on scale separation, EMD explains the generation of time series data from a novel perspective. Ensemble EMD (EEMD) is a substantial improvement of EMD which can better separate the scales naturally by adding white noise series to the original time series and then treating the ensemble averages as the true intrinsic modes. In this paper, we extend EEMD to crude oil price analysis. First, three crude oil price series with different time ranges and frequencies are decomposed into several independent intrinsic modes, from high to low frequency. Second, the intrinsic modes are composed into a fluctuating process, a slowly varying part and a trend based on fine-to-coarse reconstruction. The economic meanings of the three components are identified as short term fluctuations caused by normal supply-demand disequilibrium or some other market activities, the effect of a shock of a significant event, and a long term trend. Finally, the EEMD is shown to be a vital technique for crude oil price analysis. (author)

  4. Completeness of non-normalizable modes

    International Nuclear Information System (INIS)

    Mannheim, Philip D; Simbotin, Ionel

    2006-01-01

    We establish the completeness of some characteristic sets of non-normalizable modes by constructing fully localized square steps out of them, with each such construction expressly displaying the Gibbs phenomenon associated with trying to use a complete basis of modes to fit functions with discontinuous edges. As well as being of interest in and of itself, our study is also of interest to the recently introduced large extra dimension brane-localized gravity program of Randall and Sundrum, since the particular non-normalizable mode bases that we consider (specifically the irregular Bessel functions and the associated Legendre functions of the second kind) are associated with the tensor gravitational fluctuations which occur in those specific brane worlds in which the embedding of a maximally four-symmetric brane in a five-dimensional anti-de Sitter bulk leads to a warp factor which is divergent. Since the brane-world massless four-dimensional graviton has a divergent wavefunction in these particular cases, its resulting lack of normalizability is thus not seen to be any impediment to its belonging to a complete basis of modes, and consequently its lack of normalizability should not be seen as a criterion for not including it in the spectrum of observable modes. Moreover, because the divergent modes we consider form complete bases, we can even construct propagators out of them in which these modes appear as poles with residues which are expressly finite. Thus, even though normalizable modes appear in propagators with residues which are given as their finite normalization constants, non-normalizable modes can just as equally appear in propagators with finite residues too-it is just that such residues will not be associated with bilinear integrals of the modes

  5. Single-Mode VCSELs

    Science.gov (United States)

    Larsson, Anders; Gustavsson, Johan S.

    The only active transverse mode in a truly single-mode VCSEL is the fundamental mode with a near Gaussian field distribution. A single-mode VCSEL produces a light beam of higher spectral purity, higher degree of coherence and lower divergence than a multimode VCSEL and the beam can be more precisely shaped and focused to a smaller spot. Such beam properties are required in many applications. In this chapter, after discussing applications of single-mode VCSELs, we introduce the basics of fields and modes in VCSELs and review designs implemented for single-mode emission from VCSELs in different materials and at different wavelengths. This includes VCSELs that are inherently single-mode as well as inherently multimode VCSELs where higher-order modes are suppressed by mode selective gain or loss. In each case we present the current state-of-the-art and discuss pros and cons. At the end, a specific example with experimental results is provided and, as a summary, the most promising designs based on current technologies are identified.

  6. On the intrinsic timescales of temporal variability in measurements of the surface solar radiation

    Directory of Open Access Journals (Sweden)

    M. Bengulescu

    2018-01-01

    Full Text Available This study is concerned with the intrinsic temporal scales of the variability in the surface solar irradiance (SSI. The data consist of decennial time series of daily means of the SSI obtained from high-quality measurements of the broadband solar radiation impinging on a horizontal plane at ground level, issued from different Baseline Surface Radiation Network (BSRN ground stations around the world. First, embedded oscillations sorted in terms of increasing timescales of the data are extracted by empirical mode decomposition (EMD. Next, Hilbert spectral analysis is applied to obtain an amplitude-modulation–frequency-modulation (AM–FM representation of the data. The time-varying nature of the characteristic timescales of variability, along with the variations in the signal intensity, are thus revealed. A novel, adaptive null hypothesis based on the general statistical characteristics of noise is employed in order to discriminate between the different features of the data, those that have a deterministic origin and those being realizations of various stochastic processes. The data have a significant spectral peak corresponding to the yearly variability cycle and feature quasi-stochastic high-frequency variability components, irrespective of the geographical location or of the local climate. Moreover, the amplitude of this latter feature is shown to be modulated by variations in the yearly cycle, which is indicative of nonlinear multiplicative cross-scale couplings. The study has possible implications on the modeling and the forecast of the surface solar radiation, by clearly discriminating the deterministic from the quasi-stochastic character of the data, at different local timescales.

  7. An All Fiber Intrinsic Fabry-Perot Interferometer Based on an Air-Microcavity

    Directory of Open Access Journals (Sweden)

    Ruth I. Mata-Chávez

    2013-05-01

    Full Text Available In this work an Intrinsic Fabry-Perot Interferometer (IFPI based on an air-microcavity is presented. Here the air microcavity, with silica walls, is formed at a segment of a hollow core photonic crystal fiber (HCPCF, which is fusion spliced with a single mode fiber (SMF. Moreover, the spectral response of the IFPI is experimentally characterized and some results are provided. Finally, the viability to use the IFPI to implement a simple, compact size, and low cost refractive index sensor is briefly analyzed.

  8. Method of assessing the state of a rolling bearing based on the relative compensation distance of multiple-domain features and locally linear embedding

    Science.gov (United States)

    Kang, Shouqiang; Ma, Danyang; Wang, Yujing; Lan, Chaofeng; Chen, Qingguo; Mikulovich, V. I.

    2017-03-01

    To effectively assess different fault locations and different degrees of performance degradation of a rolling bearing with a unified assessment index, a novel state assessment method based on the relative compensation distance of multiple-domain features and locally linear embedding is proposed. First, for a single-sample signal, time-domain and frequency-domain indexes can be calculated for the original vibration signal and each sensitive intrinsic mode function obtained by improved ensemble empirical mode decomposition, and the singular values of the sensitive intrinsic mode function matrix can be extracted by singular value decomposition to construct a high-dimensional hybrid-domain feature vector. Second, a feature matrix can be constructed by arranging each feature vector of multiple samples, the dimensions of each row vector of the feature matrix can be reduced by the locally linear embedding algorithm, and the compensation distance of each fault state of the rolling bearing can be calculated using the support vector machine. Finally, the relative distance between different fault locations and different degrees of performance degradation and the normal-state optimal classification surface can be compensated, and on the basis of the proposed relative compensation distance, the assessment model can be constructed and an assessment curve drawn. Experimental results show that the proposed method can effectively assess different fault locations and different degrees of performance degradation of the rolling bearing under certain conditions.

  9. Personality traits associated with intrinsic academic motivation in medical students.

    Science.gov (United States)

    Tanaka, Masaaki; Mizuno, Kei; Fukuda, Sanae; Tajima, Seiki; Watanabe, Yasuyoshi

    2009-04-01

    Motivation is one of the most important psychological concepts in education and is related to academic outcomes in medical students. In this study, the relationships between personality traits and intrinsic academic motivation were examined in medical students. The study group consisted of 119 Year 2 medical students at Osaka City University Graduate School of Medicine. They completed questionnaires dealing with intrinsic academic motivation (the Intrinsic Motivation Scale toward Learning) and personality (the Temperament and Character Inventory [TCI]). On simple regression analyses, the TCI dimensions of persistence, self-directedness, co-operativeness and self-transcendence were positively associated with intrinsic academic motivation. On multiple regression analysis adjusted for age and gender, the TCI dimensions of persistence, self-directedness and self-transcendence were positively associated with intrinsic academic motivation. The temperament dimension of persistence and the character dimensions of self-directedness and self-transcendence are associated with intrinsic academic motivation in medical students.

  10. Streaming gravity mode instability

    International Nuclear Information System (INIS)

    Wang Shui.

    1989-05-01

    In this paper, we study the stability of a current sheet with a sheared flow in a gravitational field which is perpendicular to the magnetic field and plasma flow. This mixing mode caused by a combined role of the sheared flow and gravity is named the streaming gravity mode instability. The conditions of this mode instability are discussed for an ideal four-layer model in the incompressible limit. (author). 5 refs

  11. Decoding Mode-mixing in Black-hole Merger Ringdown

    Science.gov (United States)

    Kelly, Bernard J.; Baker, John G.

    2013-01-01

    Optimal extraction of information from gravitational-wave observations of binary black-hole coalescences requires detailed knowledge of the waveforms. Current approaches for representing waveform information are based on spin-weighted spherical harmonic decomposition. Higher-order harmonic modes carrying a few percent of the total power output near merger can supply information critical to determining intrinsic and extrinsic parameters of the binary. One obstacle to constructing a full multi-mode template of merger waveforms is the apparently complicated behavior of some of these modes; instead of settling down to a simple quasinormal frequency with decaying amplitude, some |m| = modes show periodic bumps characteristic of mode-mixing. We analyze the strongest of these modes the anomalous (3, 2) harmonic mode measured in a set of binary black-hole merger waveform simulations, and show that to leading order, they are due to a mismatch between the spherical harmonic basis used for extraction in 3D numerical relativity simulations, and the spheroidal harmonics adapted to the perturbation theory of Kerr black holes. Other causes of mode-mixing arising from gauge ambiguities and physical properties of the quasinormal ringdown modes are also considered and found to be small for the waveforms studied here.

  12. Antipastorialism : Resistant Georgic Mode

    National Research Council Canada - National Science Library

    Zimmerman, Donald

    2000-01-01

    .... Abolitionists, women, Afro-British slaves, and those who protested land enclosure developed a multivalent, resistant mode of writing, which I name 'antipastoralism', that countered orthodox, poetical...

  13. Nonlinear drift tearing mode

    International Nuclear Information System (INIS)

    Zelenyj, L.M.; Kuznetsova, M.M.

    1989-01-01

    Nonlinear study of magnetic perturbation development under single-mode conditions in collision-free plasma in configurations with the magnetic field shear is investigated. Results are obtained with regard of transverse component of electrical field and its effect on ion dynamics within wide range of ion Larmor radius value and values of magnetic field shear. Increments of nonlinear drift tearing mode are obtained and it is shown that excitation drastic conditions of even linearly stable modes are possible. Mechanism of instability nonlinear stabilization is considered and the value of magnetic island at the saturation threshold is estimeted. Energy of nonlinear drift tearing mode is discussed

  14. Sources of intrinsic rotation in the low-flow ordering

    International Nuclear Information System (INIS)

    Parra, Felix I.; Barnes, Michael; Catto, Peter J.

    2011-01-01

    A low flow, δf gyrokinetic formulation to obtain the intrinsic rotation profiles is presented. The momentum conservation equation in the low-flow ordering contains new terms, neglected in previous first-principles formulations, that may explain the intrinsic rotation observed in tokamaks in the absence of external sources of momentum. The intrinsic rotation profile depends on the density and temperature profiles and on the up-down asymmetry.

  15. Increased intrinsic mitochondrial function in humans with mitochondrial haplogroup H

    DEFF Research Database (Denmark)

    Larsen, Steen; Díez-Sánchez, Carmen; Rabøl, Rasmus

    2014-01-01

    and determined their mitochondrial haplogroup, mitochondrial oxidative phosphorylation capacity (OXPHOS), mitochondrial content (citrate synthase (CS)) and VO2max. Intrinsic mitochondrial function is calculated as mitochondrial OXPHOS capacity divided by mitochondrial content (CS). Haplogroup H showed a 30......% higher intrinsic mitochondrial function compared with the other haplo group U. There was no relationship between haplogroups and VO2max. In skeletal muscle from men with mitochondrial haplogroup H, an increased intrinsic mitochondrial function is present....

  16. The effects of extrinsic rewards on children's intrinsic motivation

    OpenAIRE

    大槻, 千秋

    1981-01-01

    An experiment was conducted with preschool children to test whether a person's intrinsic motivation in an activity may be decreased by extrinsic salient rewards in Japan like in America. Children solved some jigsaw puzzles and received assorted candies, then they were observed how long they did other jigsaw puzzles. The results showed that the effects of extrinsic rewards on intrinsic motivation in an activity varied with the subject's social background. In uptown children's intrinsic motivat...

  17. Do intrinsic and extrinsic motivation relate differently to employee outcomes?

    OpenAIRE

    Kuvaas, Bard; Buch, Robert; Weibel, Antoinette; Dysvik, Anders; Nerstad, Christina

    2017-01-01

    In most theories that address how individual financial incentives affect work performance, researchers have assumed that two types of motivation—intrinsic and extrinsic—mediate the relationship between incentives and performance. Empirically, however, extrinsic motivation is rarely investigated. To explore the predictive validity of these theories of intrinsic and extrinsic motivation in work settings, we tested how both intrinsic and extrinsic motivation affected supervisor-ra...

  18. Language Differences and Operation Mode

    DEFF Research Database (Denmark)

    Dasi, Angels; Pedersen, Torben

    2013-01-01

    for a foreign market, so that language distance matters in the case of a home-based sales force, while language incidence is key when operating through a local agent. The hypotheses are tested on a large data set encompassing 462 multinational corporations headquartered in Finland, South Korea, New Zealand......Language serves different purposes depending on the international activity in question. Language has many dimensions and firms’ communicative requirements vary by operational platform. We argue that different dimensions of language vary in their importance depending on the operation mode chosen......, and Sweden that have undertaken a business operation in a foreign country....

  19. Dynamo mode dynamics in reversed field pinches

    Science.gov (United States)

    Fitzpatrick, Richard

    1999-11-01

    Reversed field pinches (RFPs) are unstable to multiple m=1 tearing modes, resonant in the plasma core. These ``dynamo modes'' are ultimately responsible for the dynamo action which maintains the reversal of the edge toroidal magnetic field against ohmic decay. Unfortunately, the dynamo modes also generally disrupt magnetic flux surfaces in the core, thereby strongly degrading the plasma confinement. However, recent experiments in the Madison Symmetric Torus (MST) and the Reversed Field Experiment (RFX) indicate that a well-confined RFP plasma is a possibility provided that the amplitude of the dynamo modes is controlled, and the rotation of these modes is also maintained. An analytic formalism has been developed in order to investigate the nonlinear interaction of dynamo modes with one another, with static error-fields, and with eddy currents excited in the vacuum vessel or stabilizing shell. The dynamo modes are found to couple nonlinearly to form a toroidally localized magnetic structure which can be identified as the ``slinky mode,'' reported in many RFP experiments. As the mode amplitudes increase, the slinky mode forms via a series of bifurcations in which the overall mode structure and the plasma rotation profile both change discontinuously. The threshold amplitude for the onset of these bifurcations is similar to that observed experimentally. The absence of mode rotation in RFX (which gives rise to serious edge loading problems) is shown to be due to strong eddy currents excited in the resistive vacuum vessel. Dynamo modes are slowed down by these eddy currents to such an extent that they are easily locked by small static error-fields which would otherwise (i.e., in the absence of the vacuum vessel eddy currents) be unable to affect the mode rotation. Since MST does not possess a resistive vacuum vessel (in MST the thick stabilizing shell also plays the role of the vacuum vessel: in RFX there is a separate vacuum vessel inside the shell) there are no vacuum

  20. Biodiversity Conservation: Why Local Inhabitants Destroy Habitat In ...

    African Journals Online (AJOL)

    This review identifies some intrinsic and extrinsic factors that tend to drive the destruction of habitat, game poaching and unsustainable utilization of plants products by communities surrounding many protected areas around the world, leading to wildlife and plant species decline. Intrinsic factors are basic needs of the locals; ...

  1. Interventions for primary (intrinsic tracheomalacia in children

    Directory of Open Access Journals (Sweden)

    Vikas Goyal

    Full Text Available BACKGROUNDTracheomalacia, a disorder of the large airways where the trachea is deformed or malformed during respiration, is commonly seen in tertiary paediatric practice. It is associated with a wide spectrum of respiratory symptoms from life-threatening recurrent apnoea to common respiratory symptoms such as chronic cough and wheeze. Current practice following diagnosis of tracheomalacia includes medical approaches aimed at reducing associated symptoms of tracheomalacia, ventilation modalities of continuous positive airway pressure (CPAP and bi-level positive airway pressure (BiPAP, and surgical approaches aimed at improving the calibre of the airway (airway stenting, aortopexy, tracheopexy.OBJECTIVESTo evaluate the efficacy of medical and surgical therapies for children with intrinsic (primary tracheomalacia.METHODSSearchThe Cochrane Airways Group searched the Cochrane Central Register of Controlled Trials (CENTRAL, the Cochrane Airways Group's Specialized Register, Medline and Embase databases. The Cochrane Airways Group performed the latest searches in March 2012.Selection criteriaAll randomized controlled trials (RCTs of therapies related to symptoms associated with primary or intrinsic tracheomalacia.Data collection and analysisTwo reviewers extracted data from the included study independently and resolved disagreements by consensus.MAIN RESULTSWe included one RCT that compared nebulized recombinant human deoxyribonuclease (rhDNase with placebo in 40 children with airway malacia and a respiratory tract infection. We assessed it to be a RCT with overall low risk of bias. Data analyzed in this review showed that there was no significant difference between groups for the primary outcome of proportion cough-free at two weeks (odds ratio (OR 1.38; 95% confidence interval (CI 0.37 to 5.14. However, the mean change in night time cough diary scores significantly favoured the placebo group (mean difference (MD 1.00; 95% CI 0.17 to 1.83, P = 0

  2. LONG-TERM MONITORING OF MODE SWITCHING FOR PSR B0329+54

    International Nuclear Information System (INIS)

    Chen, J. L.; Wang, N.; Liu, Z. Y.; Yuan, J. P.; Wang, H. G.; Lyne, A.; Jessner, A.; Kramer, M.

    2011-01-01

    The mode-switching phenomenon of PSR B0329+54 is investigated based on the long-term monitoring from 2003 September to 2009 April made with the Urumqi 25 m radio telescope at 1540 MHz. At that frequency, the change of relative intensity between the leading and trailing components is the predominant feature of mode switching. The intensity ratios between the leading and trailing components are measured for the individual profiles averaged over a few minutes. It is found that the ratios follow normal distributions, where the abnormal mode has a greater typical width than the normal mode, indicating that the abnormal mode is less stable than the normal mode. Our data show that 84.9% of the time for PSR B0329+54 was in the normal mode and 15.1% was in the abnormal mode. From the two passages of eight-day quasi-continuous observations in 2004, supplemented by the daily data observed with the 15 m telescope at 610 MHz at Jodrell Bank Observatory, the intrinsic distributions of mode timescales are constrained with the Bayesian inference method. It is found that the gamma distribution with the shape parameter slightly smaller than 1 is favored over the normal, log-normal, and Pareto distributions. The optimal scale parameters of the gamma distribution are 31.5 minutes for the abnormal mode and 154 minutes for the normal mode. The shape parameters have very similar values, i.e., 0.75 +0.22 – 0 .17 for the normal mode and 0.84 +0.28 – 0 .22 for the abnormal mode, indicating that the physical mechanisms in both modes may be the same. No long-term modulation of the relative intensity ratios was found for either mode, suggesting that the mode switching was stable. The intrinsic timescale distributions, constrained for this pulsar for the first time, provide valuable information to understand the physics of mode switching.

  3. Task-free presurgical mapping using functional magnetic resonance imaging intrinsic activity.

    Science.gov (United States)

    Liu, Hesheng; Buckner, Randy L; Talukdar, Tanveer; Tanaka, Naoaki; Madsen, Joseph R; Stufflebeam, Steven M

    2009-10-01

    Low-frequency components of the spontaneous functional MR imaging signal provide information about the intrinsic functional and anatomical organization of the brain. The ability to use such methods in individual patients may provide a powerful tool for presurgical planning. The authors explore the feasibility of presurgical motor function mapping in which a task-free paradigm is used. Six surgical candidates with tumors or epileptic foci near the motor cortex participated in this study. The investigators directly compared task-elicited activation of the motor system to activation obtained from intrinsic activity correlations. The motor network within the unhealthy hemisphere was identified based on intrinsic activity correlations, allowing distortions of functional anatomy caused by the tumor and epilepsy to be directly visualized. The precision of the motor function mapping was further explored in 1 participant by using direct cortical stimulation. The motor regions localized based on the spontaneous activity correlations were quite similar to the regions defined by actual movement tasks and cortical stimulation. Using intrinsic activity correlations, it was possible to map the motor cortex in presurgical patients. This task-free paradigm may provide a powerful approach to map functional anatomy in patients without task compliance and allow multiple brain systems to be determined in a single scanning session.

  4. Integrity of Cerebellar Fastigial Nucleus Intrinsic Neurons Is Critical for the Global Ischemic Preconditioning

    Directory of Open Access Journals (Sweden)

    Eugene V. Golanov

    2017-09-01

    Full Text Available Excitation of intrinsic neurons of cerebellar fastigial nucleus (FN renders brain tolerant to local and global ischemia. This effect reaches a maximum 72 h after the stimulation and lasts over 10 days. Comparable neuroprotection is observed following sublethal global brain ischemia, a phenomenon known as preconditioning. We hypothesized that FN may participate in the mechanisms of ischemic preconditioning as a part of the intrinsic neuroprotective mechanism. To explore potential significance of FN neurons in brain ischemic tolerance we lesioned intrinsic FN neurons with excitotoxin ibotenic acid five days before exposure to 20 min four-vessel occlusion (4-VO global ischemia while analyzing neuronal damage in Cornu Ammoni area 1 (CA1 hippocampal area one week later. In FN-lesioned animals, loss of CA1 cells was higher by 22% compared to control (phosphate buffered saline (PBS-injected animals. Moreover, lesion of FN neurons increased morbidity following global ischemia by 50%. Ablation of FN neurons also reversed salvaging effects of five-minute ischemic preconditioning on CA1 neurons and morbidity, while ablation of cerebellar dentate nucleus neurons did not change effect of ischemic preconditioning. We conclude that FN is an important part of intrinsic neuroprotective system, which participates in ischemic preconditioning and may participate in naturally occurring neuroprotection, such as “diving response”.

  5. Understanding oceanic migrations with intrinsic biogeochemical markers.

    Directory of Open Access Journals (Sweden)

    Raül Ramos

    2009-07-01

    Full Text Available Migratory marine vertebrates move annually across remote oceanic water masses crossing international borders. Many anthropogenic threats such as overfishing, bycatch, pollution or global warming put millions of marine migrants at risk especially during their long-distance movements. Therefore, precise knowledge about these migratory movements to understand where and when these animals are more exposed to human impacts is vital for addressing marine conservation issues. Because electronic tracking devices suffer from several constraints, mainly logistical and financial, there is emerging interest in finding appropriate intrinsic markers, such as the chemical composition of inert tissues, to study long-distance migrations and identify wintering sites. Here, using tracked pelagic seabirds and some of their own feathers which were known to be grown at different places and times within the annual cycle, we proved the value of biogeochemical analyses of inert tissue as tracers of marine movements and habitat use. Analyses of feathers grown in summer showed that both stable isotope signatures and element concentrations can signal the origin of breeding birds feeding in distinct water masses. However, only stable isotopes signalled water masses used during winter because elements mainly accumulated during the long breeding period are incorporated into feathers grown in both summer and winter. Our findings shed new light on the simple and effective assignment of marine organisms to distinct oceanic areas, providing new opportunities to study unknown migration patterns of secretive species, including in relation to human-induced mortality on specific populations in the marine environment.

  6. Exploiting intrinsic fluctuations to identify model parameters.

    Science.gov (United States)

    Zimmer, Christoph; Sahle, Sven; Pahle, Jürgen

    2015-04-01

    Parameterisation of kinetic models plays a central role in computational systems biology. Besides the lack of experimental data of high enough quality, some of the biggest challenges here are identification issues. Model parameters can be structurally non-identifiable because of functional relationships. Noise in measured data is usually considered to be a nuisance for parameter estimation. However, it turns out that intrinsic fluctuations in particle numbers can make parameters identifiable that were previously non-identifiable. The authors present a method to identify model parameters that are structurally non-identifiable in a deterministic framework. The method takes time course recordings of biochemical systems in steady state or transient state as input. Often a functional relationship between parameters presents itself by a one-dimensional manifold in parameter space containing parameter sets of optimal goodness. Although the system's behaviour cannot be distinguished on this manifold in a deterministic framework it might be distinguishable in a stochastic modelling framework. Their method exploits this by using an objective function that includes a measure for fluctuations in particle numbers. They show on three example models, immigration-death, gene expression and Epo-EpoReceptor interaction, that this resolves the non-identifiability even in the case of measurement noise with known amplitude. The method is applied to partially observed recordings of biochemical systems with measurement noise. It is simple to implement and it is usually very fast to compute. This optimisation can be realised in a classical or Bayesian fashion.

  7. Does intrinsic motivation enhance motor cortex excitability?

    Science.gov (United States)

    Radel, Rémi; Pjevac, Dusan; Davranche, Karen; d'Arripe-Longueville, Fabienne; Colson, Serge S; Lapole, Thomas; Gruet, Mathieu

    2016-11-01

    Intrinsic motivation (IM) is often viewed as a spontaneous tendency for action. Recent behavioral and neuroimaging evidence indicate that IM, in comparison to extrinsic motivation (EM), solicits the motor system. Accordingly, we tested whether IM leads to greater excitability of the motor cortex than EM. To test this hypothesis, we used two different tasks to induce the motivational orientation using either words representing each motivational orientation or pictures previously linked to each motivational orientation through associative learning. Single-pulse transcranial magnetic stimulation over the motor cortex was applied when viewing the stimuli. Electromyographic activity was recorded on the contracted first dorsal interosseous muscle. Two indexes of corticospinal excitability (the amplitude of motor-evoked potential and the length of cortical silent period) were obtained through unbiased automatic detection and analyzed using a mixed model that provided both statistical power and a high level of control over all important individual, task, and stimuli characteristics. Across the two tasks and the two indices of corticospinal excitability, the exposure to IM-related stimuli did not lead to a greater corticospinal excitability than EM-related stimuli or than stimuli with no motivational valence (ps > .20). While these results tend to dismiss the advantage of IM at activating the motor cortex, we suggest alternative hypotheses to explain this lack of effect, which deserves further research. © 2016 Society for Psychophysiological Research.

  8. Dynamic Neural Fields with Intrinsic Plasticity.

    Science.gov (United States)

    Strub, Claudius; Schöner, Gregor; Wörgötter, Florentin; Sandamirskaya, Yulia

    2017-01-01

    Dynamic neural fields (DNFs) are dynamical systems models that approximate the activity of large, homogeneous, and recurrently connected neural networks based on a mean field approach. Within dynamic field theory, the DNFs have been used as building blocks in architectures to model sensorimotor embedding of cognitive processes. Typically, the parameters of a DNF in an architecture are manually tuned in order to achieve a specific dynamic behavior (e.g., decision making, selection, or working memory) for a given input pattern. This manual parameters search requires expert knowledge and time to find and verify a suited set of parameters. The DNF parametrization may be particular challenging if the input distribution is not known in advance, e.g., when processing sensory information. In this paper, we propose the autonomous adaptation of the DNF resting level and gain by a learning mechanism of intrinsic plasticity (IP). To enable this adaptation, an input and output measure for the DNF are introduced, together with a hyper parameter to define the desired output distribution. The online adaptation by IP gives the possibility to pre-define the DNF output statistics without knowledge of the input distribution and thus, also to compensate for changes in it. The capabilities and limitations of this approach are evaluated in a number of experiments.

  9. Diffuse intrinsic pontine glioma: poised for progress

    International Nuclear Information System (INIS)

    Warren, Katherine E.

    2012-01-01

    Diffuse intrinsic pontine gliomas (DIPGs) are amongst the most challenging tumors to treat. Surgery is not an option, the effects of radiation therapy are temporary, and no chemotherapeutic agent has demonstrated significant efficacy. Numerous clinical trials of new agents and novel therapeutic approaches have been performed over the course of several decades in efforts to improve the outcome of children with DIPG, yet without success. The diagnosis of DIPG is based on radiographic findings in the setting of a typical clinical presentation, and tissue is not routinely obtained as the standard of care. The paradigm for treating children with these tumors has been based on that for supratentorial high-grade gliomas in adults as the biology of these lesions were presumed to be similar. However, recent pivotal studies demonstrate that DIPGs appear to be their own entity. Simply identifying this fact releases a number of constraints and opens opportunities for biologic investigation of these lesions, setting the stage to move forward in identifying DIPG-specific treatments. This review will summarize the current state of knowledge of DIPG, discuss obstacles to therapy, and summarize results of recent biologic studies.

  10. Intrinsic gain modulation and adaptive neural coding.

    Directory of Open Access Journals (Sweden)

    Sungho Hong

    2008-07-01

    Full Text Available In many cases, the computation of a neural system can be reduced to a receptive field, or a set of linear filters, and a thresholding function, or gain curve, which determines the firing probability; this is known as a linear/nonlinear model. In some forms of sensory adaptation, these linear filters and gain curve adjust very rapidly to changes in the variance of a randomly varying driving input. An apparently similar but previously unrelated issue is the observation of gain control by background noise in cortical neurons: the slope of the firing rate versus current (f-I curve changes with the variance of background random input. Here, we show a direct correspondence between these two observations by relating variance-dependent changes in the gain of f-I curves to characteristics of the changing empirical linear/nonlinear model obtained by sampling. In the case that the underlying system is fixed, we derive relationships relating the change of the gain with respect to both mean and variance with the receptive fields derived from reverse correlation on a white noise stimulus. Using two conductance-based model neurons that display distinct gain modulation properties through a simple change in parameters, we show that coding properties of both these models quantitatively satisfy the predicted relationships. Our results describe how both variance-dependent gain modulation and adaptive neural computation result from intrinsic nonlinearity.

  11. Toward a tripartite model of intrinsic motivation.

    Science.gov (United States)

    Carbonneau, Noémie; Vallerand, Robert J; Lafrenière, Marc-André K

    2012-10-01

    Intrinsic motivation (IM) refers to engaging in an activity for the pleasure inherent in the activity. The present article presents a tripartite model of IM consisting of IM to know (i.e., engaging in an activity to experience pleasure while learning and trying to understand something new), IM toward accomplishment (i.e., engaging in an activity for the pleasure experienced when attempting task mastery), and IM to experience stimulation (i.e., engaging in an activity for feelings of sensory pleasure). The tripartite model of IM posits that each type of IM can result from task, situational, and personality determinants and can lead to specific types of cognitive, affective, and behavioral outcomes. The purpose of this research was to test some predictions derived from this model. Across 4 studies (Study 1: N = 331; Study 2: N = 113; Study 3: N = 58; Study 4: N = 135), the 3 types of IM as well as potential determinants and consequences were assessed. Results revealed that experiencing one type of IM over the others depends in part on people's personality styles. Also, each type of IM was found to predict specific outcomes (i.e., affective states and behavioral choices). The implications of the tripartite model of IM for motivation research are discussed. © 2011 The Authors. Journal of Personality © 2011, Wiley Periodicals, Inc.

  12. Rates, intrinsic linkages, and multistate population dynamics.

    Science.gov (United States)

    Schoen, Robert

    2017-01-01

    Demographic analyses of multistate populations are commonplace, as are situations where population stocks are known but population flows are not. Still, demographic models for multistate populations with changing rates remain at an early stage of development, limiting dynamic analyses and analytical projections. Here, a new approach, the Intrinsic Linkage-Rate Ratio (IL-RR) model, is presented and explored. The key IL parameter, w , is a simple weight for projecting populations. Using the ultimate state composition implied by the prevailing rates, the IL-RR model provides new relationships that connect multistate populations over time and allow analytical population projections. Parameter w reflects population metabolism and scales the level of the transfer rates. Compositional change is driven by the sequence of implicit stable population compositions. The IL-RR approach also provides a new method for estimating transfer rates within an interval from population numbers at the beginning and end of the interval. The new relationships developed advance the ability of demographers to model multistate populations with changing rates and to relate population stocks and flows.

  13. Decoupling between the hand territory and the default mode network after bilateral arm transplantation: four-year follow-up case study.

    Science.gov (United States)

    Hernandez-Castillo, Carlos R; Diedrichsen, Jörn; Aguilar-Castañeda, Erika; Iglesias, Martin

    2018-02-01

    Several studies have suggested both a local and network reorganization of the sensorimotor system following amputation. Transplantation of a new limb results in a new shifting of cortical activity in the local territory of the transplanted limb. However, there is a lack of information about the reversibility of the abnormalities at the network level. The objective of this study was to characterize the functional connectivity changes between the cortical territory of the new hand and two intrinsic network of interest: the sensorimotor network (SMN) and the default mode network (DMN) of one patient whom received bilateral forearm transplants. Using resting-state fMRI these two networks were identified across four different time points, starting four months after the transplantation surgery and during three consecutive years while the patient underwent physical rehabilitation. The topology of the SMN was disrupted at the first acquisition and over the years returned to its canonical pattern. Analysis of the DMN showed the normal topology with no significant changes across acquisitions. Functional connectivity between the missing hand's cortical territory and the SMN increased over time. Accordingly, functional connectivity between the missing hand's cortical territory and the DMN became anticorrelated over time. Our results suggest that after transplantation a new reorganization occurs at the network level, supporting the idea that extreme behavioral changes can affect not only the local rewiring but also the intrinsic network organization in neurologically healthy subjects. Overall this study provides new insight on the complex dynamics of brain organization.

  14. Intrinsic network connectivity and own body perception in gender dysphoria.

    Science.gov (United States)

    Feusner, Jamie D; Lidström, Andreas; Moody, Teena D; Dhejne, Cecilia; Bookheimer, Susan Y; Savic, Ivanka

    2017-08-01

    Gender dysphoria (GD) is characterized by incongruence between one's identity and gender assigned at birth. The biological mechanisms of GD are unclear. We investigated brain network connectivity patterns involved in own body perception in the context of self in GD. Twenty-seven female-to-male (FtM) individuals with GD, 27 male controls, and 27 female controls underwent resting state fMRI. We compared functional connections within intrinsic connectivity networks involved in self-referential processes and own body perception -default mode network (DMN) and salience network - and visual networks, using independent components analyses. Behavioral correlates of network connectivity were also tested using self-perception ratings while viewing own body images morphed to their sex assigned at birth, and to the sex of their gender identity. FtM exhibited decreased connectivity of anterior and posterior cingulate and precuneus within the DMN compared with controls. In FtM, higher "self" ratings for bodies morphed towards the sex of their gender identity were associated with greater connectivity of the anterior cingulate within the DMN, during long viewing times. In controls, higher ratings for bodies morphed towards their gender assigned at birth were associated with right insula connectivity within the salience network, during short viewing times. Within visual networks FtM showed weaker connectivity in occipital and temporal regions. Results suggest disconnectivity within networks involved in own body perception in the context of self in GD. Moreover, perception of bodies in relation to self may be reflective rather than reflexive, as a function of mesial prefrontal processes. These may represent neurobiological correlates to the subjective disconnection between perception of body and self-identification.

  15. Surgical Treatment Guidelines for Digital Deformity Associated With Intrinsic Muscle Spasticity (Intrinsic Plus Foot) in Adults With Cerebral Palsy.

    Science.gov (United States)

    Boffeli, Troy J; Collier, Rachel C

    2015-01-01

    Intrinsic plus foot deformity has primarily been associated with cerebral palsy and involves spastic contracture of the intrinsic musculature with resultant toe deformities. Digital deformity is caused by a dynamic imbalance between the intrinsic muscles in the foot and extrinsic muscles in the lower leg. Spastic contracture of the toes frequently involves curling under of the lesser digits or contracture of the hallux into valgus or plantarflexion deformity. Patients often present with associated pressure ulcers, deformed toenails, shoe or brace fitting challenges, and pain with ambulation or transfers. Four different patterns of intrinsic plus foot deformity have been observed by the authors that likely relate to the different patterns of muscle involvement. Case examples are provided of the 4 patterns of intrinsic plus foot deformity observed, including global intrinsic plus lesser toe deformity, isolated intrinsic plus lesser toe deformity, intrinsic plus hallux valgus deformity, and intrinsic plus hallux flexus deformity. These case examples are presented to demonstrate each type of deformity and our approach for surgical management according to the contracture pattern. The surgical approach has typically involved tenotomy, capsulotomy, or isolated joint fusion. The main goals of surgical treatment are to relieve pain and reduce pressure points through digital realignment in an effort to decrease the risk of pressure sores and allow more effective bracing to ultimately improve the patient's mobility. Copyright © 2015 American College of Foot and Ankle Surgeons. Published by Elsevier Inc. All rights reserved.

  16. On the development of an intrinsic hybrid composite

    International Nuclear Information System (INIS)

    Kießling, R; Ihlemann, J; Riemer, M; Drossel, W-G; Scharf, I; Lampke, T; Sharafiev, S; Pouya, M; Wagner, M F-X

    2016-01-01

    Hybrid parts, which combine low weight with high strength, are moving into the focus of the automotive industry, due to their high potential for usage in the field of crash-relevant structures. In this contribution, the development of an intrinsic hybrid composite is presented, with a focus on the manufacturing process, complex simulations of the material behaviour and material testing. The hybrid composite is made up of a continuous fibre- reinforced plastic (FRP), in which a metallic insert is integrated. The mechanical behaviour of the individual components is characterised. For material modelling, an approach is pointed out that enables modelling at large strains by directly connected rheological elements. The connection between the FRP and the metallic insert is realised by a combination of form fit and adhesive bonds. On the one hand, adhesive bonds are generated within a sol gel process. On the other hand, local form elements of the metallic insert are pressed into the FRP. We show how these form elements are generated during the macroscopic forming process. In addition, the applied sol gel process is explained. Finally, we consider design concepts for a specimen type for high strain testing of the resulting interfaces. (paper)

  17. State-dependent intrinsic predictability of cortical network dynamics.

    Directory of Open Access Journals (Sweden)

    Leila Fakhraei

    Full Text Available The information encoded in cortical circuit dynamics is fleeting, changing from moment to moment as new input arrives and ongoing intracortical interactions progress. A combination of deterministic and stochastic biophysical mechanisms governs how cortical dynamics at one moment evolve from cortical dynamics in recently preceding moments. Such temporal continuity of cortical dynamics is fundamental to many aspects of cortex function but is not well understood. Here we study temporal continuity by attempting to predict cortical population dynamics (multisite local field potential based on its own recent history in somatosensory cortex of anesthetized rats and in a computational network-level model. We found that the intrinsic predictability of cortical dynamics was dependent on multiple factors including cortical state, synaptic inhibition, and how far into the future the prediction extends. By pharmacologically tuning synaptic inhibition, we obtained a continuum of cortical states with asynchronous population activity at one extreme and stronger, spatially extended synchrony at the other extreme. Intermediate between these extremes we observed evidence for a special regime of population dynamics called criticality. Predictability of the near future (10-100 ms increased as the cortical state was tuned from asynchronous to synchronous. Predictability of the more distant future (>1 s was generally poor, but, surprisingly, was higher for asynchronous states compared to synchronous states. These experimental results were confirmed in a computational network model of spiking excitatory and inhibitory neurons. Our findings demonstrate that determinism and predictability of network dynamics depend on cortical state and the time-scale of the dynamics.

  18. The interplay of intrinsic and extrinsic bounded noises in biomolecular networks.

    Science.gov (United States)

    Caravagna, Giulio; Mauri, Giancarlo; d'Onofrio, Alberto

    2013-01-01

    After being considered as a nuisance to be filtered out, it became recently clear that biochemical noise plays a complex role, often fully functional, for a biomolecular network. The influence of intrinsic and extrinsic noises on biomolecular networks has intensively been investigated in last ten years, though contributions on the co-presence of both are sparse. Extrinsic noise is usually modeled as an unbounded white or colored gaussian stochastic process, even though realistic stochastic perturbations are clearly bounded. In this paper we consider Gillespie-like stochastic models of nonlinear networks, i.e. the intrinsic noise, where the model jump rates are affected by colored bounded extrinsic noises synthesized by a suitable biochemical state-dependent Langevin system. These systems are described by a master equation, and a simulation algorithm to analyze them is derived. This new modeling paradigm should enlarge the class of systems amenable at modeling. We investigated the influence of both amplitude and autocorrelation time of a extrinsic Sine-Wiener noise on: (i) the Michaelis-Menten approximation of noisy enzymatic reactions, which we show to be applicable also in co-presence of both intrinsic and extrinsic noise, (ii) a model of enzymatic futile cycle and (iii) a genetic toggle switch. In (ii) and (iii) we show that the presence of a bounded extrinsic noise induces qualitative modifications in the probability densities of the involved chemicals, where new modes emerge, thus suggesting the possible functional role of bounded noises.

  19. Intrinsic non-inductive current driven by ETG turbulence in tokamaks

    Science.gov (United States)

    Singh, Rameswar; Kaw, P. K.; Singh, R.; Gürcan, Ã.-. D.

    2017-10-01

    Motivated by observations and physics understanding of the phenomenon of intrinsic rotation, it is suggested that similar considerations for electron dynamics may result in intrinsic current in tokamaks. We have investigated the possibility of intrinsic non-inductive current in the turbulent plasma of tokamaks. Ohm's law is generalized to include the effect of turbulent fluctuations in the mean field approach. This clearly leads to the identification of sources and the mechanisms of non-inductive current drive by electron temperature gradient turbulence. It is found that a mean parallel electro-motive force and hence a mean parallel current can be generated by (1) the divergence of residual current flux density and (2) a non-flux like turbulent source from the density and parallel electric field correlations. Both residual flux and the non-flux source require parallel wave-number k∥ symmetry breaking for their survival which can be supplied by various means like mean E × B shear, turbulence intensity gradient, etc. Estimates of turbulence driven current are compared with the background bootstrap current in the pedestal region. It is found that turbulence driven current is nearly 10% of the bootstrap current and hence can have a significant influence on the equilibrium current density profiles and current shear driven modes.

  20. The interplay of intrinsic and extrinsic bounded noises in biomolecular networks.

    Directory of Open Access Journals (Sweden)

    Giulio Caravagna

    Full Text Available After being considered as a nuisance to be filtered out, it became recently clear that biochemical noise plays a complex role, often fully functional, for a biomolecular network. The influence of intrinsic and extrinsic noises on biomolecular networks has intensively been investigated in last ten years, though contributions on the co-presence of both are sparse. Extrinsic noise is usually modeled as an unbounded white or colored gaussian stochastic process, even though realistic stochastic perturbations are clearly bounded. In this paper we consider Gillespie-like stochastic models of nonlinear networks, i.e. the intrinsic noise, where the model jump rates are affected by colored bounded extrinsic noises synthesized by a suitable biochemical state-dependent Langevin system. These systems are described by a master equation, and a simulation algorithm to analyze them is derived. This new modeling paradigm should enlarge the class of systems amenable at modeling. We investigated the influence of both amplitude and autocorrelation time of a extrinsic Sine-Wiener noise on: (i the Michaelis-Menten approximation of noisy enzymatic reactions, which we show to be applicable also in co-presence of both intrinsic and extrinsic noise, (ii a model of enzymatic futile cycle and (iii a genetic toggle switch. In (ii and (iii we show that the presence of a bounded extrinsic noise induces qualitative modifications in the probability densities of the involved chemicals, where new modes emerge, thus suggesting the possible functional role of bounded noises.

  1. Railway Wheel Flat Detection Based on Improved Empirical Mode Decomposition

    Directory of Open Access Journals (Sweden)

    Yifan Li

    2016-01-01

    Full Text Available This study explores the capacity of the improved empirical mode decomposition (EMD in railway wheel flat detection. Aiming at the mode mixing problem of EMD, an EMD energy conservation theory and an intrinsic mode function (IMF superposition theory are presented and derived, respectively. Based on the above two theories, an improved EMD method is further proposed. The advantage of the improved EMD is evaluated by a simulated vibration signal. Then this method is applied to study the axle box vibration response caused by wheel flats, considering the influence of both track irregularity and vehicle running speed on diagnosis results. Finally, the effectiveness of the proposed method is verified by a test rig experiment. Research results demonstrate that the improved EMD can inhibit mode mixing phenomenon and extract the wheel fault characteristic effectively.

  2. General coupled mode theory in non-Hermitian waveguides.

    Science.gov (United States)

    Xu, Jing; Chen, Yuntian

    2015-08-24

    In the presence of loss and gain, the coupled mode equation on describing the mode hybridization of various waveguides or cavities, or cavities coupled to waveguides becomes intrinsically non-Hermitian. In such non-Hermitian waveguides, the standard coupled mode theory fails. We generalize the coupled mode theory with a properly defined inner product based on reaction conservation. We apply our theory to the non-Hermitian parity-time symmetric waveguides, and obtain excellent agreement with results obtained by finite element fullwave simulations. The theory presented here is typically formulated in space to study coupling between waveguides, which can be transformed into time domain by proper reformulation to study coupling between non-Hermitian resonators. Our theory has the strength of studying non-Hermitian optical systems with inclusion of the full vector fields, thus is useful to study and design non-Hermitian devices that support asymmetric and even nonreciprocal light propagations.

  3. Univariate and Bivariate Empirical Mode Decomposition for Postural Stability Analysis

    Directory of Open Access Journals (Sweden)

    Jacques Duchêne

    2008-05-01

    Full Text Available The aim of this paper was to compare empirical mode decomposition (EMD and two new extended methods of  EMD named complex empirical mode decomposition (complex-EMD and bivariate empirical mode decomposition (bivariate-EMD. All methods were used to analyze stabilogram center of pressure (COP time series. The two new methods are suitable to be applied to complex time series to extract complex intrinsic mode functions (IMFs before the Hilbert transform is subsequently applied on the IMFs. The trace of the analytic IMF in the complex plane has a circular form, with each IMF having its own rotation frequency. The area of the circle and the average rotation frequency of IMFs represent efficient indicators of the postural stability status of subjects. Experimental results show the effectiveness of these indicators to identify differences in standing posture between groups.

  4. Enhancement of lung sounds based on empirical mode decomposition and Fourier transform algorithm.

    Science.gov (United States)

    Mondal, Ashok; Banerjee, Poulami; Somkuwar, Ajay

    2017-02-01

    There is always heart sound (HS) signal interfering during the recording of lung sound (LS) signals. This obscures the features of LS signals and creates confusion on pathological states, if any, of the lungs. In this work, a new method is proposed for reduction of heart sound interference which is based on empirical mode decomposition (EMD) technique and prediction algorithm. In this approach, first the mixed signal is split into several components in terms of intrinsic mode functions (IMFs). Thereafter, HS-included segments are localized and removed from them. The missing values of the gap thus produced, is predicted by a new Fast Fourier Transform (FFT) based prediction algorithm and the time domain LS signal is reconstructed by taking an inverse FFT of the estimated missing values. The experiments have been conducted on simulated and recorded HS corrupted LS signals at three different flow rates and various SNR levels. The performance of the proposed method is evaluated by qualitative and quantitative analysis of the results. It is found that the proposed method is superior to the baseline method in terms of quantitative and qualitative measurement. The developed method gives better results compared to baseline method for different SNR levels. Our method gives cross correlation index (CCI) of 0.9488, signal to deviation ratio (SDR) of 9.8262, and normalized maximum amplitude error (NMAE) of 26.94 for 0 dB SNR value. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  5. Comparison of MHD simulation codes for understanding nonlinear ELMs dynamics in KSTAR H-mode plasma

    Science.gov (United States)

    Kim, M.; Lee, J.; Park, H. K.; Yun, G. S.; Xu, X.; Jardin, S. C.; Becoulet, M.

    2017-10-01

    KSTAR electron cyclotron emission imaging (ECEI) systems have contributed to understanding the fundamental physics of ELMs by high-quality 2D and quasi-3D images of ELMs. However, in the highly nonlinear phase of ELM dynamics, the interpretation of ECE signals becomes complicated intrinsically. Theoretical and numerical approaches are necessary to enhance the understanding of ELM physics. Well-established MHD codes (BOUT + + , JOREK, and M3D-C1) are introduced for comparative study with the observations. The nonlinear solutions are obtained using the same equilibrium of the KSTAR H-mode plasma. Each code shows the partial difference in mode evolution, probably, due to the difference in optimized operation window of initial conditions. The nonlinear simulation results show that low- n (n qualitatively matches with the recent ECEI observation just before ELM-crash, or excitation of non-modal solitary perturbation (typically, n = 1) which is highly localized in poloidal and toroidal. Regardless of differences in details, qualitative similarity can provide inspiration to understand the triggering of ELM-crash. This work is supported by NRF of Korea under Contract No. NRF-2014M1A7A1A03029865.

  6. Adolescents' Perceptions of Family Connectedness, Intrinsic Religiosity, and Depressed Mood

    Science.gov (United States)

    Houltberg, Benjamin J.; Henry, Carolyn S.; Merten, Michael J.; Robinson, Linda C.

    2011-01-01

    Using a sample of 248 ninth and tenth grade students at public high schools, we examined adolescents' perceptions of family connectedness, intrinsic religiosity, and adolescents' gender in relation to depressed mood and whether intrinsic religiosity and gender moderated the association of aspects of family connectedness to adolescent depressed…

  7. Palatalization and Intrinsic Prosodic Vowel Features in Russian

    Science.gov (United States)

    Ordin, Mikhail

    2011-01-01

    The presented study is aimed at investigating the interaction of palatalization and intrinsic prosodic features of the vowel in CVC (consonant+vowel+consonant) syllables in Russian. The universal nature of intrinsic prosodic vowel features was confirmed with the data from the Russian language. It was found that palatalization of the consonants…

  8. Self-Determination Theory: Intrinsic Motivation and Behavioral Change.

    Science.gov (United States)

    Flannery, Marie

    2017-03-01

    Motivation is a central concept in behavioral change. This article reviews the self-determination theory with an emphasis on "intrinsic motivation," which is facilitated when three basic psychological needs (autonomy, competence, and relatedness) are met. Intrinsic motivation is associated with improved well-being and sustained behavioral change.

  9. Elderly Taiwanese's Intrinsic Risk Factors for Fall-related Injuries

    Directory of Open Access Journals (Sweden)

    In-Fun Li

    2016-09-01

    Conclusion: Elderly Taiwanese inpatients with existing intrinsic conditions of cancer, vertigo, and lower leg weakness were at high risk of falling, resulting in severe injuries. Additional research including controlled trials is necessary to further identify treatable, causal intrinsic risk factors for this elderly group.

  10. Intrinsic antecedents of academic research productivity of a large ...

    African Journals Online (AJOL)

    Kirstam

    Intrinsic antecedents of academic research productivity of a large South African university. 175 influences as given, certain theory predicts that individual intrinsic differences can be associated with differences in individual job performance. Positive affectivity, or affect, can contribute to job satisfaction, as a result of the fit.

  11. Intrinsic religiosity reduces intergroup hostility under mortality salience

    NARCIS (Netherlands)

    De Zavala, Agnieszka Golec; Cichocka, Aleksandra; Orehek, Edward; Abdollahi, Abdolhossein

    Results of three studies indicate that intrinsic religiosity and mortality salience interact to predict intergroup hostility. Study 1, conducted among 200 American Christians and Jews, reveals that under mortality salience, intrinsic (but not extrinsic or quest) religiosity is related to decreased

  12. Extrinsic Rewards and Intrinsic Motivation in Children. Final Report.

    Science.gov (United States)

    Lepper, Mark R.

    Three experiments were conducted to examine the effects of providing extrinsic rewards for engaging in an activity on children's subsequent intrinsic interest in that activity. In each study, preschool children were asked to engage in an activity of initial intrinsic interest in individual experimental sessions. The children agreed to engage in…

  13. Creativity as Mediator for Intrinsic Motivation and Sales Performance

    Science.gov (United States)

    Bodla, Mahmood A.; Naeem, Basharat

    2014-01-01

    Substantial theoretical and empirical literature indicates inconsistent performance implications of intrinsic motivation, suggesting the possibility of some explanatory mechanisms. However, little is known about the factors that might explain intrinsic motivation and sales force performance relation, particularly in highly competitive and…

  14. Intrinsic Motivation and Flow Condition on the Music Teacher's Performance

    Science.gov (United States)

    Torres Delgado, Gabriela

    2017-01-01

    The aim of these research is to identify if music teachers and teachers from other areas are intrinsically or extrinsically motivated, to identify the dimensions of the flow state, and to identify if there is a relationship between intrinsic motivation and flow state in these teachers. The sample was made up of 738 active teachers. The presence of…

  15. Intrinsic antecedents of academic research productivity of a large ...

    African Journals Online (AJOL)

    Across different contexts, the human resources literature suggests that a range of intrinsic factors – typically measured as psychographic, or intrinsic, variables – are antecedents of individual job performance. What is not clear from this literature, however, is the relative contribution of different dimensions of these factors to ...

  16. Senescence-associated intrinsic mechanisms of osteoblast dysfunctions

    DEFF Research Database (Denmark)

    Kassem, Moustapha; Trinquier, Anne Marie-Pierre Emilie

    2011-01-01

    factors, and intrinsic mechanisms caused by the osteoblast cellular senescence. The aim of this review is to provide a summary of the intrinsic senescence mechanisms affecting osteoblastic functions and how they can be targeted in order to abolish age-related osteoblastic dysfunction and bone loss...

  17. Cooperative motion of intrinsic and actuated semiflexible swimmers

    NARCIS (Netherlands)

    Llopis, I.; Pagonabarraga, I.; Lagomarsino, M.C.; Lowe, C.P.

    2013-01-01

    We examine the phenomenon of hydrodynamic-induced cooperativity for pairs of flagellated micro-organism swimmers, of which spermatozoa cells are an example. We consider semiflexible swimmers, where inextensible filaments are driven by an internal intrinsic force and torque-free mechanism (intrinsic

  18. Leadership style and employees' intrinsic job satisfaction in the ...

    African Journals Online (AJOL)

    This study investigates the impact of leadership style on employees' intrinsic job satisfaction in the Cross River State Newspaper Corporation, Calabar, Nigeria. The study examined the problem of dissatisfaction in the work place as far as intrinsic factors of job satisfaction are concerned. Structured questionnaire was used ...

  19. Inward particle transport by plasma collective modes

    International Nuclear Information System (INIS)

    Antonsen, T.; Coppi, B.; Englade, R.

    1979-01-01

    A model for the rate of density rise observed when neutral gas is fed into a plasma-containing chamber is presented for regimes where known collisional transport processes do not provide an adequate explanation. A dense layer of cold plasma produced at the edge of the plasma column and the resulting relatively sharp ion temperature gradient, as compared with the local density gradient, can lead to the excitation of electron temperature fluctuations driven by ion drift modes. The net inflow of electrons and ions that is produced by these modes has been included in a one-dimensional transport code used to simulate experiments performed by the Alcator device. The linear and quasi-linear theories of these modes are given for the regimes of interest. The cold-plasma-layer model is also consistent with the presence of an outflow of impurity ions, due to impurity driven modes, that balance the inflow produced by discrete collisions. (author)

  20. Nonlinear plastic modes in disordered solids

    NARCIS (Netherlands)

    Gartner, L.; Lerner, E.

    We propose a theoretical framework within which a robust micromechanical definition of precursors to plastic instabilities, often termed soft spots, naturally emerges. They are shown to be collective displacements (modes) ˆz that correspond to local minima of a barrier function b(ˆz), which depends

  1. Intrinsic motivation and sportsmanship: mediating role of interpersonal relationships.

    Science.gov (United States)

    Núñez, Juan L; Martín-Albo, José; Navarro, José G; Sánchez, Juana M; González-Cutre, David

    2009-06-01

    This study analyzed the mediating role of interpersonal relations between intrinsic motivation and sportsmanship. Athletes (98 men, 97 women), ages 11 to 43 years, completed measures of intrinsic motivation toward sports, self-concept of social and family relations, and sportsmanship orientation. A structural equation model indicated that self-concept of interpersonal relations mediated the relation between intrinsic motivation and sportsmanship. Also, intrinsic motivation was directly and positively associated with self-concept of interpersonal relations, which, in turn, was positively and significantly related to sportsmanship. Variances explained by self-concept of interpersonal relations and by sportsmanship were 32 and 56%, respectively. The motivational interaction between the context of interpersonal relations and the sports context proposed in the hierarchical model of intrinsic and extrinsic motivation was discussed.

  2. Motivating crowding theory - opening the black box of intrinsic motivation

    DEFF Research Database (Denmark)

    Jacobsen, Christian Bøtcher

    2010-01-01

    Public employees work for many other reasons than because they are paid for it. In other words, intrinsic motivation is an important determinant for their performance. Nonetheless, public sector organizations increasingly rely on extrinsic motivation factors such as monetary incentives to motivate...... employees. Motivation crowding theory claims that this may be at the expense of intrinsic motivation, if the extrinsic motivation factor is perceived to be controlling. On the other hand, intrinsic motivation will be enhanced (crowded in), if the extrinsic motivation factor is perceived to be supportive....... Studies have found support for the motivation crowding claim, but have neglected intrinsic motivation. This study opens the black box of intrinsic motivation and finds a meaningful distinction between task motivation and public service motivation. Among 2,772 physiotherapists in the Danish public sector...

  3. Intrinsic Evaporative Cooling by Hygroscopic Earth Materials

    Directory of Open Access Journals (Sweden)

    Alexandra R. Rempel

    2016-08-01

    Full Text Available The phase change of water from liquid to vapor is one of the most energy-intensive physical processes in nature, giving it immense potential for cooling. Diverse evaporative cooling strategies have resulted worldwide, including roof ponds and sprinklers, courtyard fountains, wind catchers with qanats, irrigated green roofs, and fan-assisted evaporative coolers. These methods all require water in bulk liquid form. The evaporation of moisture that has been sorbed from the atmosphere by hygroscopic materials is equally energy-intensive, however, yet has not been examined for its cooling potential. In arid and semi-arid climates, hygroscopic earth buildings occur widely and are known to maintain comfortable indoor temperatures, but evaporation of moisture from their walls and roofs has been regarded as unimportant since water scarcity limits irrigation and rainfall; instead, their cool interiors are attributed to well-established mass effects in delaying the transmission of sensible gains. Here, we investigate the cooling accomplished by daily cycles of moisture sorption and evaporation which, requiring only ambient humidity, we designate as “intrinsic” evaporative cooling. Connecting recent soil science to heat and moisture transport studies in building materials, we use soils, adobe, cob, unfired earth bricks, rammed earth, and limestone to reveal the effects of numerous parameters (temperature and relative humidity, material orientation, thickness, moisture retention properties, vapor diffusion resistance, and liquid transport properties on the magnitude of intrinsic evaporative cooling and the stabilization of indoor relative humidity. We further synthesize these effects into concrete design guidance. Together, these results show that earth buildings in diverse climates have significant potential to cool themselves evaporatively through sorption of moisture from humid night air and evaporation during the following day’s heat. This finding

  4. Switch mode power supply

    International Nuclear Information System (INIS)

    Kim, Hui Jun

    1993-06-01

    This book concentrates on switch mode power supply. It has four parts, which are introduction of switch mode power supply with DC-DC converter such as Buck converter boost converter, Buck-boost converter and PWM control circuit, explanation for SMPS with DC-DC converter modeling and power mode control, resonance converter like resonance switch, converter, multi resonance converter and series resonance and parallel resonance converters, basic test of SMPS with PWM control circuit, Buck converter, Boost converter, flyback converter, forward converter and IC for control circuit.

  5. Surface modes in physics

    CERN Document Server

    Sernelius, Bo E

    2011-01-01

    Electromagnetic surface modes are present at all surfaces and interfaces between material of different dielectric properties. These modes have very important effects on numerous physical quantities: adhesion, capillary force, step formation and crystal growth, the Casimir effect etc. They cause surface tension and wetting and they give rise to forces which are important e.g. for the stability of colloids.This book is a useful and elegant approach to the topic, showing how the concept of electromagnetic modes can be developed as a unifying theme for a range of condensed matter physics. The

  6. Study of complex modes

    International Nuclear Information System (INIS)

    Pastrnak, J.W.

    1986-01-01

    This eighteen-month study has been successful in providing the designer and analyst with qualitative guidelines on the occurrence of complex modes in the dynamics of linear structures, and also in developing computer codes for determining quantitatively which vibration modes are complex and to what degree. The presence of complex modes in a test structure has been verified. Finite element analysis of a structure with non-proportional dumping has been performed. A partial differential equation has been formed to eliminate possible modeling errors

  7. A curvature-dependent membrane binding by tyrosine kinase Fer involves an intrinsically disordered region.

    Science.gov (United States)

    Yamamoto, Hikaru; Kondo, Akihiro; Itoh, Toshiki

    2018-01-01

    Tyrosine kinases are important enzymes that mediate signal transduction at the plasma membrane. While the significance of membrane localization of tyrosine kinases has been well evaluated, the role of membrane curvature in their regulation is unknown. Here, we demonstrate that an intrinsically disordered region in the tyrosine kinase Fer acts as a membrane curvature sensor that preferentially binds to highly curved membranes in vitro. This region forms an amphipathic α-helix upon interaction with curved membranes, aligning hydrophobic residues on one side of the helical structure. Further, the tyrosine kinase activity of Fer is significantly enhanced by the membrane in a manner dependent on curvature. We propose a model for the regulation of Fer based on an intramolecular interaction and the curvature-dependent membrane binding mediated by its intrinsically disordered region. Copyright © 2017 Elsevier Inc. All rights reserved.

  8. Intrinsic electronic defects and multiple-atom processes in the oxidic semiconductor Ga2O3

    Science.gov (United States)

    Schmeißer, Dieter; Henkel, Karsten

    2018-04-01

    We report on the electronic structure of gallium oxide (Ga2O3) single crystals as studied by resonant photoelectron spectroscopy (resPES). We identify intrinsic electronic defects that are formed by mixed-atomic valence states. We differentiate three coexisting defect states that differ in their electronic correlation energy and their spatial localization lengths. Their relative abundance is described by a fractional ionicity with covalent and ionic bonding contributions. For Ga2O3, our analyses of the resPES data enable us to derive two main aspects: first, experimental access is given to determine the ionicity based on the original concepts of Pauling and Phillips. Second, we report on multi-atomic energy loss processes in the Ga2p core level and X-ray absorption data. The two experimental findings can be explained consistently in the same context of mixed-atomic valence states and intrinsic electronic defects.

  9. Intrinsic magnetism and spontaneous band gap opening in bilayer silicene and germanene.

    Science.gov (United States)

    Wang, Xinquan; Wu, Zhigang

    2017-01-18

    It has been long sought to create magnetism out of simple non-magnetic materials, such as silicon and germanium. Here we show that intrinsic magnetism exists in bilayer silicene and germanene with no need to cut, etch, or dope. Unlike bilayer graphene, strong covalent interlayer bonding formed in bilayer silicene and germanene breaks the original π-bonding network of each layer, leaving the unbonded electrons unpaired and localized to carry magnetic moments. These magnetic moments then couple ferromagnetically within each layer while antiferromagnetically across two layers, giving rise to an infinite magnetic sheet with structural integrity and magnetic homogeneity. Furthermore, this unique magnetic ordering results in fundamental band gaps of 0.55 eV and 0.32 eV for bilayer silicene and germanene, respectively. The integration of intrinsic magnetism and spontaneous band gap opening makes bilayer silicene and germanene attractive for future nanoelectronics as well as spin-based computation and data storage.

  10. Bearing Fault Diagnosis Based on Statistical Locally Linear Embedding

    Directory of Open Access Journals (Sweden)

    Xiang Wang

    2015-07-01

    Full Text Available Fault diagnosis is essentially a kind of pattern recognition. The measured signal samples usually distribute on nonlinear low-dimensional manifolds embedded in the high-dimensional signal space, so how to implement feature extraction, dimensionality reduction and improve recognition performance is a crucial task. In this paper a novel machinery fault diagnosis approach based on a statistical locally linear embedding (S-LLE algorithm which is an extension of LLE by exploiting the fault class label information is proposed. The fault diagnosis approach first extracts the intrinsic manifold features from the high-dimensional feature vectors which are obtained from vibration signals that feature extraction by time-domain, frequency-domain and empirical mode decomposition (EMD, and then translates the complex mode space into a salient low-dimensional feature space by the manifold learning algorithm S-LLE, which outperforms other feature reduction methods such as PCA, LDA and LLE. Finally in the feature reduction space pattern classification and fault diagnosis by classifier are carried out easily and rapidly. Rolling bearing fault signals are used to validate the proposed fault diagnosis approach. The results indicate that the proposed approach obviously improves the classification performance of fault pattern recognition and outperforms the other traditional approaches.

  11. Bearing Fault Diagnosis Based on Statistical Locally Linear Embedding.

    Science.gov (United States)

    Wang, Xiang; Zheng, Yuan; Zhao, Zhenzhou; Wang, Jinping

    2015-07-06

    Fault diagnosis is essentially a kind of pattern recognition. The measured signal samples usually distribute on nonlinear low-dimensional manifolds embedded in the high-dimensional signal space, so how to implement feature extraction, dimensionality reduction and improve recognition performance is a crucial task. In this paper a novel machinery fault diagnosis approach based on a statistical locally linear embedding (S-LLE) algorithm which is an extension of LLE by exploiting the fault class label information is proposed. The fault diagnosis approach first extracts the intrinsic manifold features from the high-dimensional feature vectors which are obtained from vibration signals that feature extraction by time-domain, frequency-domain and empirical mode decomposition (EMD), and then translates the complex mode space into a salient low-dimensional feature space by the manifold learning algorithm S-LLE, which outperforms other feature reduction methods such as PCA, LDA and LLE. Finally in the feature reduction space pattern classification and fault diagnosis by classifier are carried out easily and rapidly. Rolling bearing fault signals are used to validate the proposed fault diagnosis approach. The results indicate that the proposed approach obviously improves the classification performance of fault pattern recognition and outperforms the other traditional approaches.

  12. Localization transition in SU(3) gauge theory

    Science.gov (United States)

    Kovács, Tamás G.; Vig, Réka Á.

    2018-01-01

    We study the Anderson-like localization transition in the spectrum of the Dirac operator of quenched QCD. Above the deconfining transition we determine the temperature dependence of the mobility edge separating localized and delocalized eigenmodes in the spectrum. We show that the temperature where the mobility edge vanishes and localized modes disappear from the spectrum coincides with the critical temperature of the deconfining transition. We also identify topological charge related close to zero modes in the Dirac spectrum and show that they account for only a small fraction of localized modes, a fraction that is rapidly falling as the temperature increases.

  13. Quasinormal Modes and Strong Cosmic Censorship

    Science.gov (United States)

    Cardoso, Vitor; Costa, João L.; Destounis, Kyriakos; Hintz, Peter; Jansen, Aron

    2018-01-01

    The fate of Cauchy horizons, such as those found inside charged black holes, is intrinsically connected to the decay of small perturbations exterior to the event horizon. As such, the validity of the strong cosmic censorship (SCC) conjecture is tied to how effectively the exterior damps fluctuations. Here, we study massless scalar fields in the exterior of Reissner-Nordström-de Sitter black holes. Their decay rates are governed by quasinormal modes of the black hole. We identify three families of modes in these spacetimes: one directly linked to the photon sphere, well described by standard WKB-type tools; another family whose existence and time scale is closely related to the de Sitter horizon; finally, a third family which dominates for near-extremally charged black holes and which is also present in asymptotically flat spacetimes. The last two families of modes seem to have gone unnoticed in the literature. We give a detailed description of linear scalar perturbations of such black holes, and conjecture that SCC is violated in the near extremal regime.

  14. Noninvasive iPhone Measurement of Left Ventricular Ejection Fraction Using Intrinsic Frequency Methodology.

    Science.gov (United States)

    Pahlevan, Niema M; Rinderknecht, Derek G; Tavallali, Peyman; Razavi, Marianne; Tran, Thao T; Fong, Michael W; Kloner, Robert A; Csete, Marie; Gharib, Morteza

    2017-07-01

    The study is based on previously reported mathematical analysis of arterial waveform that extracts hidden oscillations in the waveform that we called intrinsic frequencies. The goal of this clinical study was to compare the accuracy of left ventricular ejection fraction derived from intrinsic frequencies noninvasively versus left ventricular ejection fraction obtained with cardiac MRI, the most accurate method for left ventricular ejection fraction measurement. After informed consent, in one visit, subjects underwent cardiac MRI examination and noninvasive capture of a carotid waveform using an iPhone camera (The waveform is captured using a custom app that constructs the waveform from skin displacement images during the cardiac cycle.). The waveform was analyzed using intrinsic frequency algorithm. Outpatient MRI facility. Adults able to undergo MRI were referred by local physicians or self-referred in response to local advertisement and included patients with heart failure with reduced ejection fraction diagnosed by a cardiologist. Standard cardiac MRI sequences were used, with periodic breath holding for image stabilization. To minimize motion artifact, the iPhone camera was held in a cradle over the carotid artery during iPhone measurements. Regardless of neck morphology, carotid waveforms were captured in all subjects, within seconds to minutes. Seventy-two patients were studied, ranging in age from 20 to 92 years old. The main endpoint of analysis was left ventricular ejection fraction; overall, the correlation between ejection fraction-iPhone and ejection fraction-MRI was 0.74 (r = 0.74; p iPhone] + 1.9). Analysis of carotid waveforms using intrinsic frequency methods can be used to document left ventricular ejection fraction with accuracy comparable with that of MRI. The measurements require no training to perform or interpret, no calibration, and can be repeated at the bedside to generate almost continuous analysis of left ventricular ejection fraction

  15. Lattice dynamics of local defects in wide-gap semiconductors; Schwingungsverhalten lokaler Defekte in Breitband-Halbleitern

    Energy Technology Data Exchange (ETDEWEB)

    Kaczmarczyk, G.

    2006-07-01

    The group III-nitrides and zinc oxide are in the focus of material research because of their high application potential. The presentation of the first UV laser diode as well as blue light emitting diodes were the preliminary highlights. Although of all technological progress many physical questions are still open. In this work some of these questions are examined experimentally with Raman-scattering and theoretically with valence-force calculations. Many physical properties such as strain and doping concentration affect the lattice dynamics. As a start the phonons of the center of the Brillouin-zone in GaN, AlN, InN and ZnO are studied with first-order Raman-scattering. These results are the basis for advanced investigations. The acoustical and optical modes at the zone boundary and their combinations and overtones are determinated from the second-order Raman-scattering. Using the valence-force calculations the experimental frequencies are assigned to particular phonon branches or points of the Brillouin zone. The second part of this work treats systematically the physics of local vibrational modes. They occur due to intrinsic defects or impurities in the semiconductors. They are investigated with respect to the vibrational properties of the unperturbed crystals. In order to assign new experimentally found structures, calculations of local vibrational modes in GaN:Mg, GaN:As and ZnO:N systems were carried out. Furthermore, the calculations in Si- and C-doped hexagonal GaN suggest the frequency range for local vibrational modes. In the last section the influence of external parameters such as temperature or strain on the phonon frequency is analyzed. It is shown, that the influence on the temperature dependence of host phonons and local vibrational modes are dominated through different effects. In case of the host phonons it is mainly due to the volume effect whereas the local modes are highly affected by the anharmonic decay. Moreover, the calculations verified

  16. VELOCITY EVOLUTION AND THE INTRINSIC COLOR OF TYPE Ia SUPERNOVAE

    International Nuclear Information System (INIS)

    Foley, Ryan J.; Sanders, Nathan E.; Kirshner, Robert P.

    2011-01-01

    To understand how best to use observations of Type Ia supernovae (SNe Ia) to obtain precise and accurate distances, we investigate the relations between spectra of SNe Ia and their intrinsic colors. Using a sample of 1630 optical spectra of 255 SNe, based primarily on data from the CfA Supernova Program, we examine how the velocity evolution and line strengths of Si II λ6355 and Ca II H and K are related to the B – V color at peak brightness. We find that the maximum-light velocity of Si II λ6355 and Ca II H and K and the maximum-light pseudo-equivalent width of Si II λ6355 are correlated with intrinsic color, with intrinsic color having a linear relation with the Si II λ6355 measurements. Ca II H and K does not have a linear relation with intrinsic color, but lower-velocity SNe tend to be intrinsically bluer. Combining the spectroscopic measurements does not improve intrinsic color inference. The intrinsic color scatter is larger for higher-velocity SNe Ia—even after removing a linear trend with velocity—indicating that lower-velocity SNe Ia are more 'standard crayons'. Employing information derived from SN Ia spectra has the potential to improve the measurements of extragalactic distances and the cosmological properties inferred from them.

  17. Ensemble Kalman filtering without the intrinsic need for inflation

    Directory of Open Access Journals (Sweden)

    M. Bocquet

    2011-10-01

    Full Text Available The main intrinsic source of error in the ensemble Kalman filter (EnKF is sampling error. External sources of error, such as model error or deviations from Gaussianity, depend on the dynamical properties of the model. Sampling errors can lead to instability of the filter which, as a consequence, often requires inflation and localization. The goal of this article is to derive an ensemble Kalman filter which is less sensitive to sampling errors. A prior probability density function conditional on the forecast ensemble is derived using Bayesian principles. Even though this prior is built upon the assumption that the ensemble is Gaussian-distributed, it is different from the Gaussian probability density function defined by the empirical mean and the empirical error covariance matrix of the ensemble, which is implicitly used in traditional EnKFs. This new prior generates a new class of ensemble Kalman filters, called finite-size ensemble Kalman filter (EnKF-N. One deterministic variant, the finite-size ensemble transform Kalman filter (ETKF-N, is derived. It is tested on the Lorenz '63 and Lorenz '95 models. In this context, ETKF-N is shown to be stable without inflation for ensemble size greater than the model unstable subspace dimension, at the same numerical cost as the ensemble transform Kalman filter (ETKF. One variant of ETKF-N seems to systematically outperform the ETKF with optimally tuned inflation. However it is shown that ETKF-N does not account for all sampling errors, and necessitates localization like any EnKF, whenever the ensemble size is too small. In order to explore the need for inflation in this small ensemble size regime, a local version of the new class of filters is defined (LETKF-N and tested on the Lorenz '95 toy model. Whatever the size of the ensemble, the filter is stable. Its performance without inflation is slightly inferior to that of LETKF with optimally tuned inflation for small interval between updates, and

  18. Plate Tearing Under Mixed Mode Loading

    DEFF Research Database (Denmark)

    Andersen, Rasmus Grau; Nielsen, Kim Lau; Felter, Christian Lotz

    2016-01-01

    Cohesive-zone finite element modeling is often the technique of choice when dealing with extensive crack growth in large-scale ductile sheet metal structures. Shell elements with in-plane dimensions much larger than the plate thickness are typically employed to discretize the structure, and thus...... the mesh cannot accurately capture the localization process that precedes ductile failure. To fertilize accurate predictions of such sheet tearing, the energy dissipated during localization must, therefore, be accounted for in the cohesive traction-separation law. The fact is that the local thinning...... in front of an advancing crack is here approximated by a 2D plane strain finite element model to facilitate a comprehensive parameter study to evaluate the mixed Mode I-Mode III load case....

  19. Some chaotic features of intrinsically coupled Josephson junctions

    International Nuclear Information System (INIS)

    Kolahchi, M.R.; Shukrinov, Yu.M.; Hamdipour, M.; Botha, A.E.; Suzuki, M.

    2013-01-01

    Highlights: ► Intrinsically coupled Josephson junctions model a high-T c superconductor. ► Intrinsically coupled Josephson junctions can act as a chaotic nonlinear system. ► Chaos could be due to resonance overlap. ► Avoiding parameters that lead to chaos is important for the design of resonators. -- Abstract: We look for chaos in an intrinsically coupled system of Josephson junctions. This study has direct applications for the high-T c resonators which require coherence amongst the junctions

  20. Congenital hypertrophy of multiple intrinsic muscles of the foot.

    Science.gov (United States)

    Shiraishi, Tomohiro; Park, Susam; Niu, Atushi; Hasegawa, Hiromi

    2014-12-01

    Congenital hypertrophy of a single intrinsic muscle of the foot is rare, and as far as we know, only six cases have been reported. We describe a case of congenital anomaly that showed hypertrophy of multiple intrinsic muscles of the foot; the affected muscles were all the intrinsic muscles of the foot except the extensor digitorum brevis or extensor hallucis. Other tissues such as adipose tissue, nervous tissue, or osseous tissue showed no abnormalities. To reduce the volume of the foot we removed parts of the enlarged muscles.

  1. Simple intrinsic defects in GaAs : numerical supplement.

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, Peter Andrew

    2012-04-01

    This Report presents numerical tables summarizing properties of intrinsic defects in gallium arsenide, GaAs, as computed by density functional theory. This Report serves as a numerical supplement to the results published in: P.A. Schultz and O.A. von Lilienfeld, 'Simple intrinsic defects in GaAs', Modelling Simul. Mater. Sci Eng., Vol. 17, 084007 (2009), and intended for use as reference tables for a defect physics package in device models. The numerical results for density functional theory calculations of properties of simple intrinsic defects in gallium arsenide are presented.

  2. Helical propensity in an intrinsically disordered protein accelerates ligand binding

    DEFF Research Database (Denmark)

    Iesmantavicius, Vytautas; Dogan, Jakob; Jemth, Per

    2014-01-01

    domain of the activator for thyroid hormone and retinoid receptors (ACTR) is intrinsically disordered and folds upon binding to the nuclear coactivator binding domain (NCBD) of the CREB binding protein. A number of mutants was designed that selectively perturbs the amount of secondary structure......Many intrinsically disordered proteins fold upon binding to other macromolecules. The secondary structure present in the well-ordered complex is often formed transiently in the unbound state. The consequence of such transient structure for the binding process is, however, not clear. The activation...... the notion of preformed secondary structure as an important determinant for molecular recognition in intrinsically disordered proteins....

  3. Brane-Localized Gravity

    CERN Document Server

    Mannheim, Philip D

    2005-01-01

    This timely and valuable book provides a detailed pedagogical introduction and treatment of the brane-localized gravity program of Randall and Sundrum, in which gravitational signals are able to localize around our four-dimensional world in the event that it is a brane embedded in an infinitely-sized, higher dimensional anti-de Sitter bulk space. A completely self-contained development of the material needed for brane-world studies is provided for both students and workers in the field, with a significant amount of the material being previously unpublished. Particular attention is given to issues not ordinarily treated in the brane-world literature, such as the completeness of tensor gravitational fluctuation modes, the causality of brane-world propagators, and the status of the massless graviton fluctuation mode in brane worlds in which it is not normalizable.

  4. Experimental studies of tearing mode and resistive wall mode dynamics in the reversed field pinch configuration

    Energy Technology Data Exchange (ETDEWEB)

    Malmberg, Jenny-Ann

    2003-06-01

    It is relatively straightforward to establish equilibrium in magnetically confined plasmas, but the plasma is frequently susceptible to a variety of instabilities that are driven by the free energy in the magnetic field or in the pressure gradient. These unstable modes exhibit effects that affect the particle, momentum and heat confinement properties of the configuration. Studies of the dynamics of several of the most important modes are the subject of this thesis. The studies are carried out on plasmas in the reversed field pinch (RFP) configuration. One phenomenon commonly observed in RFPs is mode wall locking. The localized nature of these phase- and wall locked structures results in localized power loads on the wall which are detrimental for confinement. A detailed study of the wall locked mode phenomenon is performed based on magnetic measurements from three RFP devices. The two possible mechanisms for wall locking are investigated. Locking as a result of tearing modes interacting with a static field error and locking due to the presence of a non-ideal boundary. The characteristics of the wall locked mode are qualitatively similar in a device with a conducting shell system (TPE-RX) compared to a device with a resistive shell (Extrap T2). A theoretical model is used for evaluating the threshold values for wall locking due to eddy currents in the vacuum vessel in these devices. A good correlation with experiment is observed for the conducting shell device. The possibility of successfully sustaining discharges in a resistive shell RFP is introduced in the recently rebuilt device Extrap T2R. Fast spontaneous mode rotation is observed, resulting in low magnetic fluctuations, low loop voltage and improved confinement. Wall locking is rarely observed. The low tearing mode amplitudes allow for the theoretically predicted internal non-resonant on-axis resistive wall modes to be observed. These modes have not previously been distinguished due to the formation of wall

  5. Optical dielectric function of intrinsic amorphous silicon

    International Nuclear Information System (INIS)

    Ching, W.Y.; Lin, C.C.

    1978-01-01

    The imaginary part of the optical dielectric function epsilon 2 (ω) has been calculated using a continuous-random-tetrahedral network as the structural model for the atomic positions. Here the electronic energies and wave functions are determined by first-principles calculations with the method of linear combinations of atomic orbitals (LCAO), and the momentum matrix elements are evaluated directly from the LCAO wave functions. The calculated dielectric function is in good overall agreement with experiment. At energies within 1 eV above the threshold, the epsilon 2 curve shows some structures that are due to interband transitions between the localized states near the band gap

  6. High n ballooning modes in highly elongated tokamaks

    International Nuclear Information System (INIS)

    An, C.H.; Bateman, G.

    1980-02-01

    An analytic study of stability against high n ballooning modes in highly elongated axisymmetric plasmas is presented and compared with computational results. From the equation for the marginal pressure gradient, it is found that the local shear plays an important role on the stability of elongated and shifted plasma, and that high elongation deteriorates the stability by decreasing the stabilizing effects of field line bending and local shear. The net contribution of the local shear to stability decreases with elongation and shift for strongly ballooning modes (eigenfunctions strongly localized near the outer edge of the toroidal flux surfaces) but increases for interchange modes (eigenfunctions more uniform along the flux surfaces). The computational study of high n ballooning modes in a highly elongated plasma reveals that lowering the aspect ratio and broadening the pressure profile enhance the marginal beta for β/sub p/ less than unity but severely reduce the marginal beta for β/sub p/ larger than unity

  7. THE PULSATION MODE OF THE CEPHEID POLARIS

    Energy Technology Data Exchange (ETDEWEB)

    Turner, D. G. [Department of Astronomy and Physics, Saint Mary' s University, Halifax NS B3H 3C3 (Canada); Kovtyukh, V. V.; Usenko, I. A. [Astronomical Observatory, Odessa National University, and Isaac Newton Institute of Chile, Odessa Branch, T. G. Shevkenko Park, 65014 Odessa (Ukraine); Gorlova, N. I., E-mail: turner@ap.smu.ca [Institute of Astronomy, Celestijnenlaan 200D, B-3001 Leuven (Belgium)

    2013-01-01

    A previously derived photometric parallax of 10.10 {+-} 0.20 mas, d = 99 {+-} 2 pc, is confirmed for Polaris by a spectroscopic parallax derived using line ratios in high dispersion spectra for the Cepheid. The resulting estimates for the mean luminosity of (M{sub V} ) = -3.07 {+-} 0.01 s.e., average effective temperature of (T{sub eff}) = 6025 {+-} 1 K s.e., and intrinsic color of ((B) - (V)){sub 0} = +0.56 {+-} 0.01 s.e., which match values obtained previously from the photometric parallax for a space reddening of E{sub B-V} = 0.02 {+-} 0.01, are consistent with fundamental mode pulsation for Polaris and a first crossing of the instability strip, as also argued by its rapid rate of period increase. The systematically smaller Hipparcos parallax for Polaris appears discrepant by comparison.

  8. Local Publications.

    Science.gov (United States)

    Wilson, Yvonne; And Others

    1991-01-01

    Includes annotations for 23 local government publications that reflect the main issues confronting local communities, including AIDS, children at risk, homelessness, human rights, and environmental decline. The shift of local problem solving from the federal and state government levels to the local level is briefly discussed. (LRW)

  9. Discrete mode lasers for communications applications

    Science.gov (United States)

    Barry, L. P.; Herbert, C.; Jones, D.; Kaszubowska-Anandarajah, A.; Kelly, B.; O'Carroll, J.; Phelan, R.; Anandarajah, P.; Shi, K.; O'Gorman, J.

    2009-02-01

    The wavelength spectra of ridge waveguide Fabry Perot lasers can be modified by perturbing the effective refractive index of the guided mode along very small sections of the laser cavity. One way of locally perturbing the effective index of the lasing mode is by etching features into the ridge waveguide such that each feature has a small overlap with the transverse field profile of the unperturbed mode, consequently most of the light in the laser cavity is unaffected by these perturbations. A proportion of the propagating light is however reflected at the boundaries between the perturbed and the unperturbed sections. Suitable positioning of these interfaces allows the mirror loss spectrum of a Fabry Perot laser to be manipulated. In order to achieve single longitudinal mode emission, the mirror loss of a specified mode must be reduced below that of the other cavity modes. Here we review the latest results obtained from devices containing such features. These results clearly demonstrate that these devices exceed the specifications required for a number of FTTH and Datacomms applications, such as GEPON, LX4 and CWDM. As well as this we will also present initial results on the linewidth of these devices.

  10. A Deep Learning Prediction Model Based on Extreme-Point Symmetric Mode Decomposition and Cluster Analysis

    OpenAIRE

    Li, Guohui; Zhang, Songling; Yang, Hong

    2017-01-01

    Aiming at the irregularity of nonlinear signal and its predicting difficulty, a deep learning prediction model based on extreme-point symmetric mode decomposition (ESMD) and clustering analysis is proposed. Firstly, the original data is decomposed by ESMD to obtain the finite number of intrinsic mode functions (IMFs) and residuals. Secondly, the fuzzy c-means is used to cluster the decomposed components, and then the deep belief network (DBN) is used to predict it. Finally, the reconstructed ...

  11. The Fault Diagnosis of Rolling Bearing Based on Ensemble Empirical Mode Decomposition and Random Forest

    OpenAIRE

    Qin, Xiwen; Li, Qiaoling; Dong, Xiaogang; Lv, Siqi

    2017-01-01

    Accurate diagnosis of rolling bearing fault on the normal operation of machinery and equipment has a very important significance. A method combining Ensemble Empirical Mode Decomposition (EEMD) and Random Forest (RF) is proposed. Firstly, the original signal is decomposed into several intrinsic mode functions (IMFs) by EEMD, and the effective IMFs are selected. Then their energy entropy is calculated as the feature. Finally, the classification is performed by RF. In addition, the wavelet meth...

  12. Intrinsically motivated learning in natural and artificial systems

    CERN Document Server

    Baldassarre, Gianluca

    2013-01-01

    This book presents the state of the art in research on intrinsically motivated learning and presents novel tools for research. It also identifies related scientific and technological open challenges as well as promising research directions.

  13. Towards hardware-intrinsic security foundations and practice

    CERN Document Server

    Sadeghi, Ahmad-Reza; Tuyls, Pim

    2010-01-01

    Hardware-intrinsic security is a young field dealing with secure secret key storage. This book features contributions from researchers and practitioners with backgrounds in physics, mathematics, cryptography, coding theory and processor theory.

  14. Recent Advances in Intrinsic Self-Healing Cementitious Materials.

    Science.gov (United States)

    Li, Wenting; Dong, Biqin; Yang, Zhengxian; Xu, Jing; Chen, Qing; Li, Haoxin; Xing, Feng; Jiang, Zhengwu

    2018-03-25

    Self-healing is a natural phenomenon whereby living organisms respond to damage. Recently, considerable research efforts have been invested in self-healing cementitious materials that are capable of restoring structural integrity and mechanical properties after being damaged. Inspired by nature, a variety of creative approaches are explored here based on the intrinsic or extrinsic healing mechanism. Research on new intrinsic self-healing cementitious materials with biomimetic features is on the forefront of material science, which provides a promising way to construct resilient and sustainable concrete infrastructures. Here, the current advances in the development of the intrinsic healing cementitious materials are described, and a new definition of intrinsic self-healing discussed. The methods to assess the efficiency of different healing mechanisms are briefly summarized. The critical insights are emphasized to guide the future research on the development of new self-healing cementitious materials. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Intrinsic and extrinsic motivation for stereotypic and repetitive behavior.

    Science.gov (United States)

    Joosten, Annette V; Bundy, Anita C; Einfeld, Stewart L

    2009-03-01

    This study provides evidence for intrinsic and extrinsic motivators for stereotypical and repetitive behavior in children with autism and intellectual disability and children with intellectual disability alone. We modified the Motivation Assessment Scale (MAS) (1988b); dividing it into intrinsic and extrinsic measures and adding items to assess anxiety as an intrinsic motivator. Rasch analysis of data from 279 MASs (74 children) revealed that the items formed two unidimensional scales. Anxiety was a more likely intrinsic motivator than sensory seeking for children with dual diagnoses; the reverse was true for children with intellectual disability only. Escape and gaining a tangible object were the most common extrinsic motivators for those with dual diagnoses and attention and escape for children with intellectual disability.

  16. Values, Norms, and Intrinsic Motivation to Act Proenvironmentally

    NARCIS (Netherlands)

    Steg, Linda

    2016-01-01

    Environmental problems can be reduced if people more consistently engage in proenvironmental actions. In this article, I discuss factors that motivate or inhibit individuals to act proenvironmentally. Many people are intrinsically motivated to engage in proenvironmental actions, because protecting

  17. What is Intrinsic Motivation? A Typology of Computational Approaches.

    Science.gov (United States)

    Oudeyer, Pierre-Yves; Kaplan, Frederic

    2007-01-01

    Intrinsic motivation, centrally involved in spontaneous exploration and curiosity, is a crucial concept in developmental psychology. It has been argued to be a crucial mechanism for open-ended cognitive development in humans, and as such has gathered a growing interest from developmental roboticists in the recent years. The goal of this paper is threefold. First, it provides a synthesis of the different approaches of intrinsic motivation in psychology. Second, by interpreting these approaches in a computational reinforcement learning framework, we argue that they are not operational and even sometimes inconsistent. Third, we set the ground for a systematic operational study of intrinsic motivation by presenting a formal typology of possible computational approaches. This typology is partly based on existing computational models, but also presents new ways of conceptualizing intrinsic motivation. We argue that this kind of computational typology might be useful for opening new avenues for research both in psychology and developmental robotics.

  18. Exploring the link between intrinsic motivation and quality

    Science.gov (United States)

    Christy, Steven M.

    1992-12-01

    This thesis proposes that it is workers' intrinsic motivation that leads them to produce quality work. It reviews two different types of evidence- expert opinion and empirical studies--to attempt to evaluate a link between intrinsic motivation and work quality. The thesis reviews the works of Total Quality writers and behavioral scientists for any connection they might have made between intrinsic motivation and quality. The thesis then looks at the works of Deming and his followers in an attempt to establish a match between Deming's motivational assumptions and the four task rewards in the Thomas/Tymon model of intrinsic motivation: choice, competence, meaningfulness, and progress. Based upon this analysis, it is proposed that the four Thomas/Tymon task rewards are a promising theoretical foundation for explaining the motivational basis of quality for workers in Total Quality organizations.

  19. Does displayed enthusiasm favour recall, intrinsic motivation and time estimation?

    Science.gov (United States)

    Moè, Angelica

    2016-11-01

    Displayed enthusiasm has been shown to relate to intrinsic motivation, vitality, and positive affect, but its effects on recall performance and time estimation have not yet been explored. This research aimed at studying the effects of a delivery style characterised by High Enthusiasm (HE) on recall, time estimation, and intrinsic motivation. In line with previous studies, effects on intrinsic motivation were expected. In addition, higher recall and lower time estimations were hypothesised. In two experiments, participants assigned to a HE condition or to a normal reading control condition listened to a narrative and to a descriptive passage. Then, they were asked to rate perceived time, enthusiasm, pleasure, interest, enjoyment and curiosity, before writing a free recall. Experiment 1 showed that in the HE condition, participants recalled more, were more intrinsically motivated, and expressed lower time estimations compared to the control condition. Experiment 2 confirmed the positive effects of HE reading compared to normal reading, using different passages and a larger sample.

  20. Intrinsic and extrinsic factors influencing large African herbivore movements

    NARCIS (Netherlands)

    Venter, J.A.; Prins, H.H.T.; Mashanova, A.; Boer, de W.F.; Slotow, R.

    2015-01-01

    Understanding environmental as well as anthropogenic factors that influence large herbivore ecological patterns and processes should underpin their conservation and management. We assessed the influence of intrinsic, extrinsic environmental and extrinsic anthropogenic factors on movement behaviour