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Sample records for fluctuations reveal flexible

  1. Detrended fluctuation analysis made flexible to detect range of cross-correlated fluctuations

    Science.gov (United States)

    Kwapień, Jarosław; Oświecimka, Paweł; DroŻdŻ, Stanisław

    2015-11-01

    The detrended cross-correlation coefficient ρDCCA has recently been proposed to quantify the strength of cross-correlations on different temporal scales in bivariate, nonstationary time series. It is based on the detrended cross-correlation and detrended fluctuation analyses (DCCA and DFA, respectively) and can be viewed as an analog of the Pearson coefficient in the case of the fluctuation analysis. The coefficient ρDCCA works well in many practical situations but by construction its applicability is limited to detection of whether two signals are generally cross-correlated, without the possibility to obtain information on the amplitude of fluctuations that are responsible for those cross-correlations. In order to introduce some related flexibility, here we propose an extension of ρDCCA that exploits the multifractal versions of DFA and DCCA: multifractal detrended fluctuation analysis and multifractal detrended cross-correlation analysis, respectively. The resulting new coefficient ρq not only is able to quantify the strength of correlations but also allows one to identify the range of detrended fluctuation amplitudes that are correlated in two signals under study. We show how the coefficient ρq works in practical situations by applying it to stochastic time series representing processes with long memory: autoregressive and multiplicative ones. Such processes are often used to model signals recorded from complex systems and complex physical phenomena like turbulence, so we are convinced that this new measure can successfully be applied in time-series analysis. In particular, we present an example of such application to highly complex empirical data from financial markets. The present formulation can straightforwardly be extended to multivariate data in terms of the q -dependent counterpart of the correlation matrices and then to the network representation.

  2. Fast and anisotropic flexibility-rigidity index for protein flexibility and fluctuation analysis

    Energy Technology Data Exchange (ETDEWEB)

    Opron, Kristopher [Department of Biochemistry and Molecular Biology, Michigan State University, Michigan 48824 (United States); Xia, Kelin [Department of Mathematics, Michigan State University, Michigan 48824 (United States); Wei, Guo-Wei, E-mail: wei@math.msu.edu [Department of Biochemistry and Molecular Biology, Michigan State University, Michigan 48824 (United States); Department of Mathematics, Michigan State University, Michigan 48824 (United States); Department of Electrical and Computer Engineering, Michigan State University, Michigan 48824 (United States)

    2014-06-21

    Protein structural fluctuation, typically measured by Debye-Waller factors, or B-factors, is a manifestation of protein flexibility, which strongly correlates to protein function. The flexibility-rigidity index (FRI) is a newly proposed method for the construction of atomic rigidity functions required in the theory of continuum elasticity with atomic rigidity, which is a new multiscale formalism for describing excessively large biomolecular systems. The FRI method analyzes protein rigidity and flexibility and is capable of predicting protein B-factors without resorting to matrix diagonalization. A fundamental assumption used in the FRI is that protein structures are uniquely determined by various internal and external interactions, while the protein functions, such as stability and flexibility, are solely determined by the structure. As such, one can predict protein flexibility without resorting to the protein interaction Hamiltonian. Consequently, bypassing the matrix diagonalization, the original FRI has a computational complexity of O(N{sup 2}). This work introduces a fast FRI (fFRI) algorithm for the flexibility analysis of large macromolecules. The proposed fFRI further reduces the computational complexity to O(N). Additionally, we propose anisotropic FRI (aFRI) algorithms for the analysis of protein collective dynamics. The aFRI algorithms permit adaptive Hessian matrices, from a completely global 3N × 3N matrix to completely local 3 × 3 matrices. These 3 × 3 matrices, despite being calculated locally, also contain non-local correlation information. Eigenvectors obtained from the proposed aFRI algorithms are able to demonstrate collective motions. Moreover, we investigate the performance of FRI by employing four families of radial basis correlation functions. Both parameter optimized and parameter-free FRI methods are explored. Furthermore, we compare the accuracy and efficiency of FRI with some established approaches to flexibility analysis, namely

  3. Identifying the adaptive mechanism in globular proteins: Fluctuations in densely packed regions manipulate flexible parts

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    Yilmaz, Lutfu Safak; Atilgan, Ali Rana

    2000-09-01

    A low-resolution structural model based on the packing geometry of α-carbons is utilized to establish a connection between the flexible and rigid parts of a folded protein. The former commonly recognizes a complementing molecule for making a complex, while the latter manipulates the necessary conformational change for binding. We attempt analytically to distinguish this control architecture that intrinsically exists in globular proteins. First with two-dimensional simple models, then for a native protein, bovine pancreatic trypsin inhibitor, we explicitly demonstrate that inserting fluctuations in tertiary contacts supported by the stable core, one can regulate the displacement of residues on loop regions. The positional fluctuations of the flexible regions are annihilated by the rest of the protein in conformity with the Le Chatelier-Braun principle. The results indicate that the distortion of the principal nonbonded contacts between highly packed residues is accompanied by that of the slavery fluctuations that are widely distributed over the native structure. These positional arrangements do not appear in a reciprocal relation between a perturbation and the associated response; the effect of a movement of residue i on residue j is not equal to that of the same movement of residue j on residue i.

  4. Architecture of cognitive flexibility revealed by lesion mapping

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    Barbey, Aron K.; Colom, Roberto; Grafman, Jordan

    2013-01-01

    Neuroscience has made remarkable progress in understanding the architecture of human intelligence, identifying a distributed network of brain structures that support goal-directed, intelligent behavior. However, the neural foundations of cognitive flexibility and adaptive aspects of intellectual function remain to be well characterized. Here, we report a human lesion study (n = 149) that investigates the neural bases of key competencies of cognitive flexibility (i.e., mental flexibility and the fluent generation of new ideas) and systematically examine their contributions to a broad spectrum of cognitive and social processes, including psychometric intelligence (Wechsler Adult Intelligence Scale), emotional intelligence (Mayer, Salovey, Caruso Emotional Intelligence Test), and personality (Neuroticism–Extraversion–Openness Personality Inventory). Latent variable modeling was applied to obtain error-free indices of each factor, followed by voxel-based lesion-symptom mapping to elucidate their neural substrates. Regression analyses revealed that latent scores for psychometric intelligence reliably predict latent scores for cognitive flexibility (adjusted R2 = 0.94). Lesion mapping results further indicated that these convergent processes depend on a shared network of frontal, temporal, and parietal regions, including white matter association tracts, which bind these areas into an integrated system. A targeted analysis of the unique variance explained by cognitive flexibility further revealed selective damage within the right superior temporal gyrus, a region known to support insight and the recognition of novel semantic relations. The observed findings motivate an integrative framework for understanding the neural foundations of adaptive behavior, suggesting that core elements of cognitive flexibility emerge from a distributed network of brain regions that support specific competencies for human intelligence. PMID:23721727

  5. Inertial picobalance reveals fast mass fluctuations in mammalian cells

    Science.gov (United States)

    Martínez-Martín, David; Fläschner, Gotthold; Gaub, Benjamin; Martin, Sascha; Newton, Richard; Beerli, Corina; Mercer, Jason; Gerber, Christoph; Müller, Daniel J.

    2017-10-01

    The regulation of size, volume and mass in living cells is physiologically important, and dysregulation of these parameters gives rise to many diseases. Cell mass is largely determined by the amount of water, proteins, lipids, carbohydrates and nucleic acids present in a cell, and is tightly linked to metabolism, proliferation and gene expression. Technologies have emerged in recent years that make it possible to track the masses of single suspended cells and adherent cells. However, it has not been possible to track individual adherent cells in physiological conditions at the mass and time resolutions required to observe fast cellular dynamics. Here we introduce a cell balance (a ‘picobalance’), based on an optically excited microresonator, that measures the total mass of single or multiple adherent cells in culture conditions over days with millisecond time resolution and picogram mass sensitivity. Using our technique, we observe that the mass of living mammalian cells fluctuates intrinsically by around one to four per cent over timescales of seconds throughout the cell cycle. Perturbation experiments link these mass fluctuations to the basic cellular processes of ATP synthesis and water transport. Furthermore, we show that growth and cell cycle progression are arrested in cells infected with vaccinia virus, but mass fluctuations continue until cell death. Our measurements suggest that all living cells show fast and subtle mass fluctuations throughout the cell cycle. As our cell balance is easy to handle and compatible with fluorescence microscopy, we anticipate that our approach will contribute to the understanding of cell mass regulation in various cell states and across timescales, which is important in areas including physiology, cancer research, stem-cell differentiation and drug discovery.

  6. Listening to the Noise: Random Fluctuations Reveal Gene Network Parameters

    Science.gov (United States)

    Munsky, Brian; Trinh, Brooke; Khammash, Mustafa

    2010-03-01

    The cellular environment is abuzz with noise originating from the inherent random motion of reacting molecules in the living cell. In this noisy environment, clonal cell populations exhibit cell-to-cell variability that can manifest significant prototypical differences. Noise induced stochastic fluctuations in cellular constituents can be measured and their statistics quantified using flow cytometry, single molecule fluorescence in situ hybridization, time lapse fluorescence microscopy and other single cell and single molecule measurement techniques. We show that these random fluctuations carry within them valuable information about the underlying genetic network. Far from being a nuisance, the ever-present cellular noise acts as a rich source of excitation that, when processed through a gene network, carries its distinctive fingerprint that encodes a wealth of information about that network. We demonstrate that in some cases the analysis of these random fluctuations enables the full identification of network parameters, including those that may otherwise be difficult to measure. We use theoretical investigations to establish experimental guidelines for the identification of gene regulatory networks, and we apply these guideline to experimentally identify predictive models for different regulatory mechanisms in bacteria and yeast.

  7. Effect of flexibility on the growth of concentration fluctuations in a suspension of sedimenting fibers: Particle simulations

    Energy Technology Data Exchange (ETDEWEB)

    Manikantan, Harishankar; Saintillan, David [Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California 92093 (United States)

    2016-01-15

    Three-dimensional numerical simulations are performed to study the stability of a sedimenting suspension of weakly flexible fibers. It is well known that a suspension of rigid rods sedimenting under gravity at low Reynolds number is unstable to concentration fluctuations owing to hydrodynamic interactions. Flexible fibers, however, reorient while settling and even weak flexibility can alter their collective dynamics. In our recent work [Manikantan et al., “The instability of a sedimenting suspension of weakly flexible fibres,” J. Fluid Mech. 756, 935–964 (2014)], we developed a mean-field theory to predict the linear stability of such a system. Here, we verify these predictions using accurate and efficient particle simulations based on a slender-body model. We also demonstrate the mechanisms by which flexibility-induced reorientation alters suspension microstructure, and through it, its stability. Specifically, we first show that the anisotropy of the base state in the case of a suspension of flexible fibers has a destabilizing effect compared to a suspension of rigid rods. Second, a conflicting effect of flexibility is also shown to suppress particle clustering and slow down the growth of the instability. The relative magnitude of filament flexibility and rotational Brownian motion dictates which effect dominates, and our simulations qualitatively follow theoretically predicted trends. The mechanism for either effects is tied to the flexibility-induced reorientation of particles, which we illustrate using velocity and orientation statistics from our simulations. Finally, we also show that, in the case of an initially homogeneous and isotropic suspension, flexibility always acts to suppress the growth of the instability.

  8. Effect of flexibility on the growth of concentration fluctuations in a suspension of sedimenting fibers: Particle simulations

    International Nuclear Information System (INIS)

    Manikantan, Harishankar; Saintillan, David

    2016-01-01

    Three-dimensional numerical simulations are performed to study the stability of a sedimenting suspension of weakly flexible fibers. It is well known that a suspension of rigid rods sedimenting under gravity at low Reynolds number is unstable to concentration fluctuations owing to hydrodynamic interactions. Flexible fibers, however, reorient while settling and even weak flexibility can alter their collective dynamics. In our recent work [Manikantan et al., “The instability of a sedimenting suspension of weakly flexible fibres,” J. Fluid Mech. 756, 935–964 (2014)], we developed a mean-field theory to predict the linear stability of such a system. Here, we verify these predictions using accurate and efficient particle simulations based on a slender-body model. We also demonstrate the mechanisms by which flexibility-induced reorientation alters suspension microstructure, and through it, its stability. Specifically, we first show that the anisotropy of the base state in the case of a suspension of flexible fibers has a destabilizing effect compared to a suspension of rigid rods. Second, a conflicting effect of flexibility is also shown to suppress particle clustering and slow down the growth of the instability. The relative magnitude of filament flexibility and rotational Brownian motion dictates which effect dominates, and our simulations qualitatively follow theoretically predicted trends. The mechanism for either effects is tied to the flexibility-induced reorientation of particles, which we illustrate using velocity and orientation statistics from our simulations. Finally, we also show that, in the case of an initially homogeneous and isotropic suspension, flexibility always acts to suppress the growth of the instability

  9. Flexible Connectivity in the Aging Brain Revealed by Task Modulations

    NARCIS (Netherlands)

    Geerligs, Linda; Saliasi, Emi; Renken, Remco J.; Maurits, Natasha M.; Lorist, Monicque M.

    Recent studies have shown that aging has a large impact on connectivity within and between functional networks. An open question is whether elderly still have the flexibility to adapt functional network connectivity (FNC) to the demands of the task at hand. To study this, we collected fMRI data in

  10. Bach Is the Father of Harmony: Revealed by a 1/f Fluctuation Analysis across Musical Genres.

    Science.gov (United States)

    Wu, Dan; Kendrick, Keith M; Levitin, Daniel J; Li, Chaoyi; Yao, Dezhong

    2015-01-01

    Harmony is a fundamental attribute of music. Close connections exist between music and mathematics since both pursue harmony and unity. In music, the consonance of notes played simultaneously partly determines our perception of harmony; associates with aesthetic responses; and influences the emotion expression. The consonance could be considered as a window to understand and analyze harmony. Here for the first time we used a 1/f fluctuation analysis to investigate whether the consonance fluctuation structure in music with a wide range of composers and genres followed the scale free pattern that has been found for pitch, melody, rhythm, human body movements, brain activity, natural images and geographical features. We then used a network graph approach to investigate which composers were the most influential both within and across genres. Our results showed that patterns of consonance in music did follow scale-free characteristics, suggesting that this feature is a universally evolved one in both music and the living world. Furthermore, our network analysis revealed that Bach's harmony patterns were having the most influence on those used by other composers, followed closely by Mozart.

  11. Bach Is the Father of Harmony: Revealed by a 1/f Fluctuation Analysis across Musical Genres.

    Directory of Open Access Journals (Sweden)

    Dan Wu

    Full Text Available Harmony is a fundamental attribute of music. Close connections exist between music and mathematics since both pursue harmony and unity. In music, the consonance of notes played simultaneously partly determines our perception of harmony; associates with aesthetic responses; and influences the emotion expression. The consonance could be considered as a window to understand and analyze harmony. Here for the first time we used a 1/f fluctuation analysis to investigate whether the consonance fluctuation structure in music with a wide range of composers and genres followed the scale free pattern that has been found for pitch, melody, rhythm, human body movements, brain activity, natural images and geographical features. We then used a network graph approach to investigate which composers were the most influential both within and across genres. Our results showed that patterns of consonance in music did follow scale-free characteristics, suggesting that this feature is a universally evolved one in both music and the living world. Furthermore, our network analysis revealed that Bach's harmony patterns were having the most influence on those used by other composers, followed closely by Mozart.

  12. Flexibility.

    Science.gov (United States)

    Humphrey, L. Dennis

    1981-01-01

    Flexibility is an important aspect of all sports and recreational activities. Flexibility can be developed and maintained by stretching exercises. Exercises designed to develop flexibility in ankle joints, knees, hips, and the lower back are presented. (JN)

  13. Multichannel detrended fluctuation analysis reveals synchronized patterns of spontaneous spinal activity in anesthetized cats.

    Directory of Open Access Journals (Sweden)

    Erika E Rodríguez

    Full Text Available The analysis of the interaction and synchronization of relatively large ensembles of neurons is fundamental for the understanding of complex functions of the nervous system. It is known that the temporal synchronization of neural ensembles is involved in the generation of specific motor, sensory or cognitive processes. Also, the intersegmental coherence of spinal spontaneous activity may indicate the existence of synaptic neural pathways between different pairs of lumbar segments. In this study we present a multichannel version of the detrended fluctuation analysis method (mDFA to analyze the correlation dynamics of spontaneous spinal activity (SSA from time series analysis. This method together with the classical detrended fluctuation analysis (DFA were used to find out whether the SSA recorded in one or several segments in the spinal cord of the anesthetized cat occurs either in a random or in an organized manner. Our results are consistent with a non-random organization of the sets of neurons involved in the generation of spontaneous cord dorsum potentials (CDPs recorded either from one lumbar segment (DFA-α mean = 1.04[Formula: see text]0.09 or simultaneously from several lumbar segments (mDFA-α mean = 1.01[Formula: see text]0.06, where α = 0.5 indicates randomness while α = 0.5 indicates long-term correlations. To test the sensitivity of the mDFA method we also examined the effects of small spinal lesions aimed to partially interrupt connectivity between neighboring lumbosacral segments. We found that the synchronization and correlation between the CDPs recorded from the L5 and L6 segments in both sides of the spinal cord were reduced when a lesion comprising the left dorsal quadrant was performed between the segments L5 and L6 (mDFA-[Formula: see text] = 0.992 as compared to initial conditions mDFA-α = 1.186. The synchronization and correlation were reduced even further after a similar additional right spinal lesion (mDFA-α = 0

  14. Multifractal fluctuations in joint angles during infant spontaneous kicking reveal multiplicativity-driven coordination

    International Nuclear Information System (INIS)

    Stephen, Damian G.; Hsu, Wen-Hao; Young, Diana; Saltzman, Elliot L.; Holt, Kenneth G.; Newman, Dava J.; Weinberg, Marc; Wood, Robert J.; Nagpal, Radhika; Goldfield, Eugene C.

    2012-01-01

    Previous research has considered infant spontaneous kicking as a form of exploration. According to this view, spontaneous kicking provides information about motor degrees of freedom and may shape multijoint coordinations for more complex movement patterns such as gait. Recent work has demonstrated that multifractal, multiplicative fluctuations in exploratory movements index energy flows underlying perceptual-motor information. If infant spontaneous kicking is exploratory and occasions an upstream flow of information from the motor periphery, we expected not only that multiplicativity of fluctuations at the hip should promote multiplicativity of fluctuations at more distal joints (i.e., reflecting downstream effects of neural control) but also that multiplicativity at more distal joints should promote multiplicativity at the hip. Multifractal analysis demonstrated that infant spontaneous kicking in four typically developing infants for evidence of multiplicative fluctuations in multiple joint angles along the leg (i.e., hip, knee, and ankle) exhibited multiplicativity. Vector autoregressive modeling demonstrated that only one leg exhibited downstream effects but that both legs exhibited upstream effects. These results confirm the exploratory aspect of infant spontaneous kicking and suggest chaotic dynamics in motor coordination. They also resonate with existing models of chaos-controlled robotics and noise-based interventions for rehabilitating motor coordination in atypically developing patients.

  15. Lognormal firing rate distribution reveals prominent fluctuation-driven regime in spinal motor networks

    DEFF Research Database (Denmark)

    Petersen, Peter C.; Berg, Rune W.

    2016-01-01

    fraction that operates within either a ‘mean-driven’ or a ‘fluctuation–driven’ regime. Fluctuation-driven neurons have a ‘supralinear’ input-output curve, which enhances sensitivity, whereas the mean-driven regime reduces sensitivity. We find a rich diversity of firing rates across the neuronal population...... as reflected in a lognormal distribution and demonstrate that half of the neurons spend at least 50 %% of the time in the ‘fluctuation–driven’ regime regardless of behavior. Because of the disparity in input–output properties for these two regimes, this fraction may reflect a fine trade–off between stability...

  16. Ion mobility-mass spectrometry reveals conformational flexibility in the deubiquitinating enzyme USP5.

    Science.gov (United States)

    Scott, Daniel; Layfield, Robert; Oldham, Neil J

    2015-08-01

    Many proteins exhibit conformation flexibility as part of their biological function, whether through the presence of a series of well-defined states or by the existence of intrinsic disorder. Ion mobility spectrometry, in combination with MS (IM-MS), offers a rapid and sensitive means of probing ensembles of protein structures through measurement of gas-phase collisional cross sections. We have applied IM-MS analysis to the multidomain deubiquitinating enzyme ubiquitin specific protease 5 (USP5), which is believed to exhibit significant conformational flexibility. Native ESI-MS measurement of the 94-kDa USP5 revealed two distinct charge-state distributions: [M + 17H](+) to [M + 21H](+) and [M + 24H](+) to [M + 29H](+). The collisional cross sections of these ions revealed clear groupings of 52 ± 4 nm(2) for the lower charges and 66 ± 6 nm(2) for the higher charges. Molecular dynamics simulation of a compact form of USP5, based on a crystal structure, produced structures of 53-54 nm(2) following 2 ns in the gas phase, while simulation of an extended form (based on small-angle X-ray scattering data) led to structures of 64 nm(2). These data demonstrate that IM-MS is a valuable tool in studying proteins with different discrete conformational states. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Distinct role of hydration water in protein misfolding and aggregation revealed by fluctuating thermodynamics analysis.

    Science.gov (United States)

    Chong, Song-Ho; Ham, Sihyun

    2015-04-21

    Protein aggregation in aqueous cellular environments is linked to diverse human diseases. Protein aggregation proceeds through a multistep process initiated by conformational transitions, called protein misfolding, of monomer species toward aggregation-prone structures. Various forms of aggregate species are generated through the association of misfolded monomers including soluble oligomers and amyloid fibrils. Elucidating the molecular mechanisms and driving forces involved in the misfolding and subsequent association has been a central issue for understanding and preventing protein aggregation diseases such as Alzheimer's, Parkinson's, and type II diabetes. In this Account, we provide a thermodynamic perspective of the misfolding and aggregation of the amyloid-beta (Aβ) protein implicated in Alzheimer's disease through the application of fluctuating thermodynamics. This approach "dissects" the conventional thermodynamic characterization of the end states into the one of the fluctuating processes connecting them, and enables one to analyze variations in the thermodynamic functions that occur during the course of protein conformational changes. The central quantity in this approach is the solvent-averaged effective energy, f = Eu + Gsolv, comprising the protein potential energy (Eu) and the solvation free energy (Gsolv), whose time variation reflects the protein dynamics on the free energy landscape. Protein configurational entropy is quantified by the magnitude of fluctuations in f. We find that misfolding of the Aβ monomer when released from a membrane environment to an aqueous phase is driven by favorable changes in protein potential energy and configurational entropy, but it is also accompanied by an unfavorable increase in solvation free energy. The subsequent dimerization of the misfolded Aβ monomers occurs in two steps. The first step, where two widely separated monomers come into contact distance, is driven by water-mediated attraction, that is, by a

  18. Potential Fluctuations and Localization Effects in CZTS Single Crystals, as Revealed by Optical Spectroscopy

    Science.gov (United States)

    Bleuse, Joël; Ducroquet, Frédérique; Mariette, Henri

    2018-03-01

    Reports on Cu_2 ZnSn(S_x Se_{1-x} )_4 (CZTSSe) solar cell devices all show an open-circuit voltage lower than expected, especially when compared to CuIn_x Ga_{1-x} (S,Se)_2 devices, which reduces their power efficiency and delays their development. A high concentration of intrinsic defects in CZTSSe, and their stabilization through neutral complex formation, which induces some local fluctuations, are at the origin of local energy shifts in the conduction and valence band edges. The implied band tail in Cu_2 ZnSnS_4 is studied in this work by combining three types of optical spectroscopy data: emission spectra compared to photoluminescence excitation spectroscopy, emission spectra as a function of excitation power, and time-resolved photoluminescence spectra. All these data converge to show that both the bandgap and the band tail of localized states just below are dependent on the degree of order/disorder in the Cu/Zn cation sublattice of the quaternary structure: in the more ordered structures, the bandgap increases by about 50 meV, and the energy range of the band tail is decreased from about 110 to 70 meV.

  19. Molecular Dynamics Simulations of the STAS Domains of Rat Prestin and Human Pendrin Reveal Conformational Motions in Conserved Flexible Regions

    Directory of Open Access Journals (Sweden)

    Alok K. Sharma

    2014-02-01

    domain in solution structure may be more dynamic than rat prestin STAS. Regions of prestin and pendrin identified by RMS fluctuation data as exhibiting larger atomic fluctuations corresponded to nominal GDP-binding regions of the aligned Rv1739c STAS domain of M. tuberculosis. Conclusions: MD simulations of mammalian STAS domains reveal substantial predicted conformational heterogeneity. These predicted conformational dynamics serve to supplement the reported crystal structure of the rat prestin STAS domain, and extend our understanding of the roles of STAS domains in SLC26 anion transporter function.

  20. A Flexible Maximum Power Point Tracking Control Strategy Considering Both Conversion Efficiency and Power Fluctuation for Large-inertia Wind Turbines

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    Hongmin Meng

    2017-07-01

    Full Text Available In wind turbine control, maximum power point tracking (MPPT control is the main control mode for partial-load regimes. Efficiency potentiation of energy conversion and power smoothing are both two important control objectives in partial-load regime. However, on the one hand, low power fluctuation signifies inefficiency of energy conversion. On the other hand, enhancing efficiency may increase output power fluctuation as well. Thus the two objectives are contradictory and difficult to balance. This paper proposes a flexible MPPT control framework to improve the performance of both conversion efficiency and power smoothing, by adaptively compensating the torque reference value. The compensation was determined by a proposed model predictive control (MPC method with dynamic weights in the cost function, which improved control performance. The computational burden of the MPC solver was reduced by transforming the cost function representation. Theoretical analysis proved the good stability and robustness. Simulation results showed that the proposed method not only kept efficiency at a high level, but also reduced power fluctuations as much as possible. Therefore, the proposed method could improve wind farm profits and power grid reliability.

  1. Crystal structure analysis reveals functional flexibility in the selenocysteine-specific tRNA from mouse.

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    Oleg M Ganichkin

    Full Text Available Selenocysteine tRNAs (tRNA(Sec exhibit a number of unique identity elements that are recognized specifically by proteins of the selenocysteine biosynthetic pathways and decoding machineries. Presently, these identity elements and the mechanisms by which they are interpreted by tRNA(Sec-interacting factors are incompletely understood.We applied rational mutagenesis to obtain well diffracting crystals of murine tRNA(Sec. tRNA(Sec lacking the single-stranded 3'-acceptor end ((ΔGCCARNA(Sec yielded a crystal structure at 2.0 Å resolution. The global structure of (ΔGCCARNA(Sec resembles the structure of human tRNA(Sec determined at 3.1 Å resolution. Structural comparisons revealed flexible regions in tRNA(Sec used for induced fit binding to selenophosphate synthetase. Water molecules located in the present structure were involved in the stabilization of two alternative conformations of the anticodon stem-loop. Modeling of a 2'-O-methylated ribose at position U34 of the anticodon loop as found in a sub-population of tRNA(Secin vivo showed how this modification favors an anticodon loop conformation that is functional during decoding on the ribosome. Soaking of crystals in Mn(2+-containing buffer revealed eight potential divalent metal ion binding sites but the located metal ions did not significantly stabilize specific structural features of tRNA(Sec.We provide the most highly resolved structure of a tRNA(Sec molecule to date and assessed the influence of water molecules and metal ions on the molecule's conformation and dynamics. Our results suggest how conformational changes of tRNA(Sec support its interaction with proteins.

  2. Salmon migration patterns revealed the temporal and spatial fluctuations of the radiocesium levels in terrestrial and ocean environments.

    Science.gov (United States)

    Arai, Takaomi

    2014-01-01

    The disabling of the Fukushima Daiichi Nuclear Power Plant (F1NPP) resulted in the release of radionuclides, including 134Cs and 137Cs, into the air and the ocean. The unpredicted nuclear accident is of global concern for human health and the ecosystem. Although investigations of radionuclides in environments were performed shortly after the accident started, the temporal and spatial impacts and fluctuations on the releasing radionuclides to natural environment remain unclear. I focused on salmon, which migrate from inland to the open ocean globally, to reveal the three-year (May 2011 to February 2014) fluctuations and accumulations of 134Cs and 137Cs from terrestrial to open ocean environments after the F1NPP accident. The 134Cs and 137Cs concentrations in six salmonids exhibited lower temporal variations for three years after the F1NPP accident, suggesting that these radionuclides are widely distributed and these radionuclides remain in the natural environment globally with less convergence. The accumulation patterns were significantly different among the different salmon species. Fluvial (freshwater residence) type salmons exhibited significantly higher accumulation in 134Cs (25.3-40.2 Bq kg(-1) in mean) and 137Cs (41.4-51.7 Bq kg(-1) in mean) than did the anadromous (sea-run) type salmons (0.64-8.03 Bq kg(-1) in mean 134Cs and 0.42-10.2 Bq kg(-1) in mean 137Cs) suggesting widespread contamination in terrestrial environments versus the coastal and open ocean environments. Salmonids are the most highly migratory animals and are characterised by their strong tendency to return home to their natal site for reproduction. Salmonids have a potential to be a good indicator as an effective monitoring animal.

  3. Fluctuating Charge-Order in Optimally Doped Bi- 2212 Revealed by Momentum-resolved Electron Energy Loss Spectroscopy

    Science.gov (United States)

    Husain, Ali; Vig, Sean; Kogar, Anshul; Mishra, Vivek; Rak, Melinda; Mitrano, Matteo; Johnson, Peter; Gu, Genda; Fradkin, Eduardo; Norman, Michael; Abbamonte, Peter

    Static charge order is a ubiquitous feature of the underdoped cuprates. However, at optimal doping, charge-order has been thought to be completely suppressed, suggesting an interplay between the charge-ordering and superconducting order parameters. Using Momentum-resolved Electron Energy Loss Spectroscopy (M-EELS) we show the existence of diffuse fluctuating charge-order in the optimally doped cuprate Bi2Sr2CaCu2O8+δ (Bi-2212) at low-temperature. We present full momentum-space maps of both elastic and inelastic scattering at room temperature and below the superconducting transition with 4meV resolution. We show that the ``rods'' of diffuse scattering indicate nematic-like fluctuations, and the energy width defines a fluctuation timescale of 160 fs. We discuss the implications of fluctuating charge-order on the dynamics at optimal doping. This work was supported by the Gordon and Betty Moore Foundation's EPiQS Initiative through Grant GBMF-4542. An early prototype of the M-EELS instrument was supported by the DOE Center for Emergent Superconductivity under Award No. DE-AC02-98CH10886.

  4. Role of Spontaneous Brain Activity in Explicit and Implicit Aspects of Cognitive Flexibility under Socially Conflicting Situations: A Resting-state fMRI Study using Fractional Amplitude of Low-frequency Fluctuations.

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    Fujino, Junya; Tei, Shisei; Jankowski, Kathryn F; Kawada, Ryosaku; Murai, Toshiya; Takahashi, Hidehiko

    2017-12-26

    We are constantly exposed to socially conflicting situations in everyday life, and cognitive flexibility is essential for adaptively coping with such difficulties. Flexible goal choice and pursuit are not exclusively conscious, and therefore cognitive flexibility involves both explicit and implicit forms of processing. However, it is unclear how individual differences in explicit and implicit aspects of flexibility are associated with neural activity in a resting state. Here, we measured intrinsic fractional amplitude of low-frequency fluctuations (fALFF) by resting-state functional magnetic resonance imaging (RS-fMRI) as an indicator of regional brain spontaneous activity, together with explicit and implicit aspects of cognitive flexibility using the Cognitive Flexibility Scale (CFS) and Implicit Association Test (IAT). Consistent with the dual processing theory, there was a strong association between explicit aspects of flexibility (CFS score) and "rationalism" thinking style and between implicit aspects (IAT effect) and "experientialism." The level of explicit flexibility was also correlated with fALFF values in the left lateral prefrontal cortex, whereas the level of implicit flexibility was correlated with fALFF values in the right cerebellum. Furthermore, the fALFF values in both regions predicted individual preference for flexible decision-making strategy in a vignettes simulation task. These results add to our understanding of the neural mechanisms underlying flexible decision-making for solving social conflicts. More generally, our findings highlight the utility of RS-fMRI combined with both explicit and implicit psychometric measures for better understanding individual differences in social cognition. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  5. Continuous acoustic studies of overwintering sprat Sprattus sprattus reveal flexible behavior

    KAUST Repository

    Solberg, I

    2012-09-19

    The clupeid fish Sprattus sprattus was studied in a 150 m deep Norwegian fjord throughout an entire overwintering period during which the fjord froze over and a major water renewal occurred. A bottom-mounted (upward-facing) echosounder provided continuous high-resolution data and enabled studies of swimming speed and behavior of individual sprat in addition to population behavior. The continuous acoustic studies were supplemented with intermittent field campaigns. The sprat displayed different behavioral modes with changing environmental conditions. During the first part of the winter, the majority of the population occurred in deep waters during both day and night, yet exhibited a shallower night-time distribution. Individual sprat swam alternately up and down, a ‘rise and sink’ behavior likely a compensation for negative buoyancy because of swim bladder compression. Because feeding was negligible in deep waters, the swimming pattern was not inferred as prey search behavior. Another part of the population schooled at shallower depths during the day and carried out vertical migration to upper waters at night. However, individuals were observed as they switched between these behavioral groups. A sudden change in both swimming behavior and vertical distribution occurred as the fjord became ice covered. Near-bottom ‘rise and sink’ swimming was replaced by schooling in mid-water during the day, and the sprat aggregated in dense layers near the surface at night. We suggest that the ice made the sprat shift their antipredator strategy from hiding at depth to hiding in schools in the darker waters below the ice. This long-term acoustic study has shown that sprat have a flexible behavioral repertoire, displaying different overwintering strategies within a population, depending on environmental conditions.

  6. Flexibility and Stability in Sensory Processing Revealed Using Visual-to-Auditory Sensory Substitution

    Science.gov (United States)

    Hertz, Uri; Amedi, Amir

    2015-01-01

    The classical view of sensory processing involves independent processing in sensory cortices and multisensory integration in associative areas. This hierarchical structure has been challenged by evidence of multisensory responses in sensory areas, and dynamic weighting of sensory inputs in associative areas, thus far reported independently. Here, we used a visual-to-auditory sensory substitution algorithm (SSA) to manipulate the information conveyed by sensory inputs while keeping the stimuli intact. During scan sessions before and after SSA learning, subjects were presented with visual images and auditory soundscapes. The findings reveal 2 dynamic processes. First, crossmodal attenuation of sensory cortices changed direction after SSA learning from visual attenuations of the auditory cortex to auditory attenuations of the visual cortex. Secondly, associative areas changed their sensory response profile from strongest response for visual to that for auditory. The interaction between these phenomena may play an important role in multisensory processing. Consistent features were also found in the sensory dominance in sensory areas and audiovisual convergence in associative area Middle Temporal Gyrus. These 2 factors allow for both stability and a fast, dynamic tuning of the system when required. PMID:24518756

  7. Alterations in task-induced activity and resting-state fluctuations in visual and DMN areas revealed in long-term meditators.

    Science.gov (United States)

    Berkovich-Ohana, Aviva; Harel, Michal; Hahamy, Avital; Arieli, Amos; Malach, Rafael

    2016-07-15

    Recently we proposed that the information contained in spontaneously emerging (resting-state) fluctuations may reflect individually unique neuro-cognitive traits. One prediction of this conjecture, termed the "spontaneous trait reactivation" (STR) hypothesis, is that resting-state activity patterns could be diagnostic of unique personalities, talents and life-styles of individuals. Long-term meditators could provide a unique experimental group to test this hypothesis. Using fMRI we found that, during resting-state, the amplitude of spontaneous fluctuations in long-term mindfulness meditation (MM) practitioners was enhanced in the visual cortex and significantly reduced in the DMN compared to naïve controls. Importantly, during a visual recognition memory task, the MM group showed heightened visual cortex responsivity, concomitant with weaker negative responses in Default Mode Network (DMN) areas. This effect was also reflected in the behavioral performance, where MM practitioners performed significantly faster than the control group. Thus, our results uncover opposite changes in the visual and default mode systems in long-term meditators which are revealed during both rest and task. The results support the STR hypothesis and extend it to the domain of local changes in the magnitude of the spontaneous fluctuations. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. Changes in low-frequency fluctuations in patients with antisocial personality disorder revealed by resting-state functional MRI.

    Directory of Open Access Journals (Sweden)

    Huasheng Liu

    Full Text Available Antisocial Personality Disorder (APD is a personality disorder that is most commonly associated with the legal and criminal justice systems. The study of the brain in APD has important implications in legal contexts and in helping ensure social stability. However, the neural contribution to the high prevalence of APD is still unclear. In this study, we used resting-state functional magnetic resonance imaging (fMRI to investigate the underlying neural mechanisms of APD. Thirty-two healthy individuals and thirty-five patients with APD were recruited. The amplitude of low-frequency fluctuations (ALFF was analyzed for the whole brain of all subjects. Our results showed that APD patients had a significant reduction in the ALFF in the right orbitofrontal cortex, the left temporal pole, the right inferior temporal gyrus, and the left cerebellum posterior lobe compared to normal controls. We observed that the right orbitofrontal cortex had a negative correlation between ALFF values and MMPI psychopathic deviate scores. Alterations in ALFF in these specific brain regions suggest that APD patients may be associated with abnormal activities in the fronto-temporal network. We propose that our results may contribute in a clinical and forensic context to a better understanding of APD.

  9. Signature of a Nonharmonic Potential as Revealed from a Consistent Shape and Fluctuation Analysis of an Adherent Membrane

    Directory of Open Access Journals (Sweden)

    Daniel Schmidt

    2014-05-01

    Full Text Available The interaction of fluid membranes with a scaffold, which can be a planar surface or a more complex structure, is intrinsic to a number of systems from artificial supported bilayers and vesicles to cellular membranes. In principle, these interactions can be either discrete and protein mediated, or continuous. In the latter case, they emerge from ubiquitous intrinsic surface interaction potentials as well as nature-designed steric contributions of the fluctuating membrane or from the polymers of the glycocalyx. Despite the fact that these nonspecific potentials are omnipresent, their description has been a major challenge from experimental and theoretical points of view. Here, we show that a full understanding of the implications of the continuous interactions can be achieved only by expanding the standard superposition models commonly used to treat these types of systems, beyond the usual harmonic level of description. Supported by this expanded theoretical framework, we present three independent, yet mutually consistent, experimental approaches to measure the interaction potential strength and the membrane tension. Upon explicitly taking into account the nature of shot noise as well as the nature of finite experimental resolution, excellent agreement with the augmented theory is obtained, which finally provides a coherent view of the behavior of the membrane in the vicinity of a scaffold.

  10. The crystal structure of the Dachshund domain of human SnoN reveals flexibility in the putative protein interaction surface.

    Directory of Open Access Journals (Sweden)

    Tomas Nyman

    2010-09-01

    Full Text Available The human SnoN is an oncoprotein that interacts with several transcription-regulatory proteins such as the histone-deacetylase, N-CoR containing co-repressor complex and Smad proteins. This study presents the crystal structure of the Dachshund homology domain of human SnoN. The structure reveals a groove composed of conserved residues with characteristic properties of a protein-interaction surface. A comparison of the 12 monomers in the asymmetric unit reveals the presence of two major conformations: an open conformation with a well accessible groove and a tight conformation with a less accessible groove. The variability in the backbone between the open and the tight conformations matches the differences seen in previously determined structures of individual Dachshund homology domains, suggesting a general plasticity within this fold family. The flexibility observed in the putative protein binding groove may enable SnoN to recognize multiple interaction partners.This article can also be viewed as an enhanced version in which the text of the article is integrated with interactive 3D representations and animated transitions. Please note that a web plugin is required to access this enhanced functionality. Instructions for the installation and use of the web plugin are available in Text S1.

  11. Temporal Fluctuation in North East Baltic Sea Region Cattle Population Revealed by Mitochondrial and Y-Chromosomal DNA Analyses

    Science.gov (United States)

    Niemi, Marianna; Bläuer, Auli; Iso-Touru, Terhi; Harjula, Janne; Nyström Edmark, Veronica; Rannamäe, Eve; Lõugas, Lembi; Sajantila, Antti; Lidén, Kerstin; Taavitsainen, Jussi-Pekka

    2015-01-01

    Background Ancient DNA analysis offers a way to detect changes in populations over time. To date, most studies of ancient cattle have focused on their domestication in prehistory, while only a limited number of studies have analysed later periods. Conversely, the genetic structure of modern cattle populations is well known given the undertaking of several molecular and population genetic studies. Results Bones and teeth from ancient cattle populations from the North-East Baltic Sea region dated to the Prehistoric (Late Bronze and Iron Age, 5 samples), Medieval (14), and Post-Medieval (26) periods were investigated by sequencing 667 base pairs (bp) from the mitochondrial DNA (mtDNA) and 155 bp of intron 19 in the Y-chromosomal UTY gene. Comparison of maternal (mtDNA haplotypes) genetic diversity in ancient cattle (45 samples) with modern cattle populations in Europe and Asia (2094 samples) revealed 30 ancient mtDNA haplotypes, 24 of which were shared with modern breeds, while 6 were unique to the ancient samples. Of seven Y-chromosomal sequences determined from ancient samples, six were Y2 and one Y1 haplotype. Combined data including Swedish samples from the same periods (64 samples) was compared with the occurrence of Y-chromosomal haplotypes in modern cattle (1614 samples). Conclusions The diversity of haplogroups was highest in the Prehistoric samples, where many haplotypes were unique. The Medieval and Post-Medieval samples also show a high diversity with new haplotypes. Some of these haplotypes have become frequent in modern breeds in the Nordic Countries and North-Western Russia while other haplotypes have remained in only a few local breeds or seem to have been lost. A temporal shift in Y-chromosomal haplotypes from Y2 to Y1 was detected that corresponds with the appearance of new mtDNA haplotypes in the Medieval and Post-Medieval period. This suggests a replacement of the Prehistoric mtDNA and Y chromosomal haplotypes by new types of cattle. PMID:25992976

  12. Flexibility and symmetry of prokaryotic genome rearrangement reveal lineage-associated core-gene-defined genome organizational frameworks.

    Science.gov (United States)

    Kang, Yu; Gu, Chaohao; Yuan, Lina; Wang, Yue; Zhu, Yanmin; Li, Xinna; Luo, Qibin; Xiao, Jingfa; Jiang, Daquan; Qian, Minping; Ahmed Khan, Aftab; Chen, Fei; Zhang, Zhang; Yu, Jun

    2014-11-25

    The prokaryotic pangenome partitions genes into core and dispensable genes. The order of core genes, albeit assumed to be stable under selection in general, is frequently interrupted by horizontal gene transfer and rearrangement, but how a core-gene-defined genome maintains its stability or flexibility remains to be investigated. Based on data from 30 species, including 425 genomes from six phyla, we grouped core genes into syntenic blocks in the context of a pangenome according to their stability across multiple isolates. A subset of the core genes, often species specific and lineage associated, formed a core-gene-defined genome organizational framework (cGOF). Such cGOFs are either single segmental (one-third of the species analyzed) or multisegmental (the rest). Multisegment cGOFs were further classified into symmetric or asymmetric according to segment orientations toward the origin-terminus axis. The cGOFs in Gram-positive species are exclusively symmetric and often reversible in orientation, as opposed to those of the Gram-negative bacteria, which are all asymmetric and irreversible. Meanwhile, all species showing strong strand-biased gene distribution contain symmetric cGOFs and often specific DnaE (α subunit of DNA polymerase III) isoforms. Furthermore, functional evaluations revealed that cGOF genes are hub associated with regard to cellular activities, and the stability of cGOF provides efficient indexes for scaffold orientation as demonstrated by assembling virtual and empirical genome drafts. cGOFs show species specificity, and the symmetry of multisegmental cGOFs is conserved among taxa and constrained by DNA polymerase-centric strand-biased gene distribution. The definition of species-specific cGOFs provides powerful guidance for genome assembly and other structure-based analysis. Prokaryotic genomes are frequently interrupted by horizontal gene transfer (HGT) and rearrangement. To know whether there is a set of genes not only conserved in position

  13. Touchscreen-paradigm for mice reveals cross-species evidence for an antagonistic relationship of cognitive flexibility and stability

    Directory of Open Access Journals (Sweden)

    S Helene Richter

    2014-05-01

    Full Text Available The abilities to either flexibly adjust behavior according to changing demands (cognitive flexibility or to maintain it in the face of potential distractors (cognitive stability are critical for adaptive behavior in many situations. Recently, a novel human paradigm has found individual differences of cognitive flexibility and stability to be related to common prefrontal networks. The aims of the present study were, first, to translate this paradigm from humans to mice and, second, to test conceptual predictions of a computational model of prefrontal working memory mechanisms, the Dual State Theory, which assumes an antagonistic relation between cognitive flexibility and stability.Mice were trained in a touchscreen-paradigm to discriminate visual cues. The task involved ‘ongoing’ and cued ‘switch’ trials. In addition distractor cues were interspersed to test the ability to resist distraction, and an ambiguous condition assessed the spontaneous switching between two possible responses without explicit cues. While response times did not differ substantially between conditions, error rates increased from the ‘ongoing’ baseline condition to the most complex condition, where subjects were required to switch between two responses in the presence of a distracting cue. Importantly, subjects switching more often spontaneously were found to be more distractible by task irrelevant cues, but also more flexible in situations, where switching was required. These results support a dichotomy of cognitive flexibility and stability as predicted by the Dual State Theory. Furthermore, they replicate critical aspects of the human paradigm, which indicates the translational potential of the testing procedure and supports the use of touchscreen procedures in preclinical animal research.

  14. The neural basis of trait self-esteem revealed by the amplitude of low-frequency fluctuations and resting state functional connectivity.

    Science.gov (United States)

    Pan, Weigang; Liu, Congcong; Yang, Qian; Gu, Yan; Yin, Shouhang; Chen, Antao

    2016-03-01

    Self-esteem is an affective, self-evaluation of oneself and has a significant effect on mental and behavioral health. Although research has focused on the neural substrates of self-esteem, little is known about the spontaneous brain activity that is associated with trait self-esteem (TSE) during the resting state. In this study, we used the resting-state functional magnetic resonance imaging (fMRI) signal of the amplitude of low-frequency fluctuations (ALFFs) and resting state functional connectivity (RSFC) to identify TSE-related regions and networks. We found that a higher level of TSE was associated with higher ALFFs in the left ventral medial prefrontal cortex (vmPFC) and lower ALFFs in the left cuneus/lingual gyrus and right lingual gyrus. RSFC analyses revealed that the strengths of functional connectivity between the left vmPFC and bilateral hippocampus were positively correlated with TSE; however, the connections between the left vmPFC and right inferior frontal gyrus and posterior superior temporal sulcus were negatively associated with TSE. Furthermore, the strengths of functional connectivity between the left cuneus/lingual gyrus and right dorsolateral prefrontal cortex and anterior cingulate cortex were positively related to TSE. These findings indicate that TSE is linked to core regions in the default mode network and social cognition network, which is involved in self-referential processing, autobiographical memory and social cognition. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

  15. Engineered jadomycin analogues with altered sugar moieties revealing JadS as a substrate flexible O-glycosyltransferase.

    Science.gov (United States)

    Li, Liyuan; Pan, Guohui; Zhu, Xifen; Fan, Keqiang; Gao, Wubin; Ai, Guomin; Ren, Jinwei; Shi, Mingxin; Olano, Carlos; Salas, José A; Yang, Keqian

    2017-07-01

    Glycosyltransferases (GTs)-mediated glycodiversification studies have drawn significant attention recently, with the goal of generating bioactive compounds with improved pharmacological properties by diversifying the appended sugars. The key to achieving glycodiversification is to identify natural and/or engineered flexible GTs capable of acting upon a broad range of substrates. Here, we report the use of a combinatorial biosynthetic approach to probe the substrate flexibility of JadS, the GT in jadomycin biosynthesis, towards different non-native NDP-sugar substrates, enabling us to identify six jadomycin B analogues with different sugar moieties. Further structural engineering by precursor-directed biosynthesis allowed us to obtain 11 new jadomycin analogues. Our results for the first time show that JadS is a flexible O-GT that can utilize both L- and D- sugars as donor substrates, and tolerate structural changes at the C2, C4 and C6 positions of the sugar moiety. JadS may be further exploited to generate novel glycosylated jadomycin molecules in future glycodiversification studies.

  16. Global and system-specific resting-state fMRI fluctuations are uncorrelated: principal component analysis reveals anti-correlated networks.

    Science.gov (United States)

    Carbonell, Felix; Bellec, Pierre; Shmuel, Amir

    2011-01-01

    The influence of the global average signal (GAS) on functional-magnetic resonance imaging (fMRI)-based resting-state functional connectivity is a matter of ongoing debate. The global average fluctuations increase the correlation between functional systems beyond the correlation that reflects their specific functional connectivity. Hence, removal of the GAS is a common practice for facilitating the observation of network-specific functional connectivity. This strategy relies on the implicit assumption of a linear-additive model according to which global fluctuations, irrespective of their origin, and network-specific fluctuations are super-positioned. However, removal of the GAS introduces spurious negative correlations between functional systems, bringing into question the validity of previous findings of negative correlations between fluctuations in the default-mode and the task-positive networks. Here we present an alternative method for estimating global fluctuations, immune to the complications associated with the GAS. Principal components analysis was applied to resting-state fMRI time-series. A global-signal effect estimator was defined as the principal component (PC) that correlated best with the GAS. The mean correlation coefficient between our proposed PC-based global effect estimator and the GAS was 0.97±0.05, demonstrating that our estimator successfully approximated the GAS. In 66 out of 68 runs, the PC that showed the highest correlation with the GAS was the first PC. Since PCs are orthogonal, our method provides an estimator of the global fluctuations, which is uncorrelated to the remaining, network-specific fluctuations. Moreover, unlike the regression of the GAS, the regression of the PC-based global effect estimator does not introduce spurious anti-correlations beyond the decrease in seed-based correlation values allowed by the assumed additive model. After regressing this PC-based estimator out of the original time-series, we observed robust anti

  17. Genome-Wide Analysis of Transposon and Retroviral Insertions Reveals Preferential Integrations in Regions of DNA Flexibility.

    Science.gov (United States)

    Vrljicak, Pavle; Tao, Shijie; Varshney, Gaurav K; Quach, Helen Ngoc Bao; Joshi, Adita; LaFave, Matthew C; Burgess, Shawn M; Sampath, Karuna

    2016-04-07

    DNA transposons and retroviruses are important transgenic tools for genome engineering. An important consideration affecting the choice of transgenic vector is their insertion site preferences. Previous large-scale analyses of Ds transposon integration sites in plants were done on the basis of reporter gene expression or germ-line transmission, making it difficult to discern vertebrate integration preferences. Here, we compare over 1300 Ds transposon integration sites in zebrafish with Tol2 transposon and retroviral integration sites. Genome-wide analysis shows that Ds integration sites in the presence or absence of marker selection are remarkably similar and distributed throughout the genome. No strict motif was found, but a preference for structural features in the target DNA associated with DNA flexibility (Twist, Tilt, Rise, Roll, Shift, and Slide) was observed. Remarkably, this feature is also found in transposon and retroviral integrations in maize and mouse cells. Our findings show that structural features influence the integration of heterologous DNA in genomes, and have implications for targeted genome engineering. Copyright © 2016 Vrljicak et al.

  18. Quantum fluctuations

    International Nuclear Information System (INIS)

    Reynaud, S.; Giacobino, S.; Zinn-Justin, J.

    1997-01-01

    This course is dedicated to present in a pedagogical manner the recent developments in peculiar fields concerned by quantum fluctuations: quantum noise in optics, light propagation through dielectric media, sub-Poissonian light generated by lasers and masers, quantum non-demolition measurements, quantum electrodynamics applied to cavities and electrical circuits involving superconducting tunnel junctions. (A.C.)

  19. Extensive small-angle X-ray scattering studies of blood coagulation factor VIIa reveal interdomain flexibility

    DEFF Research Database (Denmark)

    Mosbæk, Charlotte Rode; Nolan, David; Persson, Egon

    2010-01-01

    Blood coagulation factor VIIa (FVIIa) is used in the treatment of replacement therapy resistant hemophilia patients, and FVIIa is normally activated upon complex formation with tissue factor (TF), potentially in context with structural rearrangements. The solution behavior of uncomplexed FVIIa...... is important for understanding the mechanism of activation and for the stability and activity of the pharmaceutical product. However, crystal structures of FVIIa in complex with TF and of truncated free FVIIa reveal different overall conformations while previous small-angle scattering studies suggest FVIIa...... causing resistance to activation, thereby emphasizing the connection between the distribution of different conformations of FVII and the mechanism of activation....

  20. Anomalous metallic state with strong charge fluctuations in BaxTi8O16 +δ revealed by hard x-ray photoemission spectroscopy

    Science.gov (United States)

    Dash, S.; Kajita, T.; Okawa, M.; Saitoh, T.; Ikenaga, E.; Saini, N. L.; Katsufuji, T.; Mizokawa, T.

    2018-04-01

    We have studied a charge-orbital driven metal-insulator transition (MIT) in hollandite-type BaxTi8O16 +δ by means of hard x-ray photoemission spectroscopy (HAXPES). The Ti 2 p HAXPES indicates strong Ti3 +/Ti4 + charge fluctuation in the metallic phase above the MIT temperature. The metallic phase is characterized by a power-law spectral function near the Fermi level which would be a signature of bad metal with non-Drude polaronic behavior. The power-law spectral shape is associated with the large Seebeck coefficient of the metallic phase in BaxTi8O16 +δ .

  1. Ferromagnetic quantum critical fluctuations and anomalous coexistence of ferromagnetism and superconductivity in UCoGe revealed by Co-NMR and NQR studies

    International Nuclear Information System (INIS)

    Ohta, Tetsuya; Nakai, Yusuke; Ihara, Yoshihiko; Ishida, Kenji; Deguchi, Kazuhiko; Sato, Noriaki K.; Satoh, Isamu

    2008-01-01

    Co nuclear magnetic resonance (NMR) and nuclear quadrupole resonance (NQR) studies were carried out for the recently discovered UCoGe, in which the ferromagnetic and superconducting (SC) transitions are reported to occur at T Curie - 3 K and T S - 0.8 K, in order to investigate the coexistence of ferromagnetism and superconductivity as well as the normal-state and SC properties from a microscopic point of view. From the nuclear spin-lattice relaxation rate 1/T 1 and Knight-shift measurements, we confirm that ferromagnetic fluctuations that possess a quantum critical character are present above T Curie and also the occurrence of a ferromagnetic transition at 2.5 K in our polycrystalline sample. The magnetic fluctuations in the normal state show that UCoGe is an itinerant ferromagnet similar to ZrZn 2 and YCo 2 . The onset SC transition is identified at T S - 0.7 K, below which 1/T 1 arising from 30% of the volume fraction starts to decrease due to the opening of the SC gap. This component of 1/T 1 , which follows a T 3 dependence in the temperature range 0.3-0.1 K, coexists with the magnetic components of 1/T 1 showing a √T dependence below T S . From the NQR measurements in the SC state, we suggest that the self-induced vortex state is realized in UCoGe. (author)

  2. A crystal structure of the Dengue virus NS5 protein reveals a novel inter-domain interface essential for protein flexibility and virus replication.

    Directory of Open Access Journals (Sweden)

    Yongqian Zhao

    2015-03-01

    Full Text Available Flavivirus RNA replication occurs within a replication complex (RC that assembles on ER membranes and comprises both non-structural (NS viral proteins and host cofactors. As the largest protein component within the flavivirus RC, NS5 plays key enzymatic roles through its N-terminal methyltransferase (MTase and C-terminal RNA-dependent-RNA polymerase (RdRp domains, and constitutes a major target for antivirals. We determined a crystal structure of the full-length NS5 protein from Dengue virus serotype 3 (DENV3 at a resolution of 2.3 Å in the presence of bound SAH and GTP. Although the overall molecular shape of NS5 from DENV3 resembles that of NS5 from Japanese Encephalitis Virus (JEV, the relative orientation between the MTase and RdRp domains differs between the two structures, providing direct evidence for the existence of a set of discrete stable molecular conformations that may be required for its function. While the inter-domain region is mostly disordered in NS5 from JEV, the NS5 structure from DENV3 reveals a well-ordered linker region comprising a short 310 helix that may act as a swivel. Solution Hydrogen/Deuterium Exchange Mass Spectrometry (HDX-MS analysis reveals an increased mobility of the thumb subdomain of RdRp in the context of the full length NS5 protein which correlates well with the analysis of the crystallographic temperature factors. Site-directed mutagenesis targeting the mostly polar interface between the MTase and RdRp domains identified several evolutionarily conserved residues that are important for viral replication, suggesting that inter-domain cross-talk in NS5 regulates virus replication. Collectively, a picture for the molecular origin of NS5 flexibility is emerging with profound implications for flavivirus replication and for the development of therapeutics targeting NS5.

  3. Fluctuation analysis

    International Nuclear Information System (INIS)

    Clarke, J.

    1980-01-01

    This paper briefly reviews sources of noise in Josephson junctions, and the limits they impose on the sensitivity of dc and rf SQUIDS. The results are strictly valid only for a resistively shunted junction (RSJ) with zero capacitance, but should be applicable to point contact junctions and microbridges in so far as these devices can be approximated by the RSJ model. Fluctuations arising from Nyquist noise in the resistive shunt of a single junction are discussed in the limit eI/sub o/R/k/sub B/T << 1 in which a classical treatment is appropriate, and then extend the treatment to the limit eI/sub o/R/k/sub B/T greater than or equal to 1 in which quantum effects become important. The Nyquist limit theory is used to calculate the noise in a dc SQUID, and the results are compared with a number of practical devices. The quantum limit is briefly considered. Results for the predicted sensitivity of rf SQUIDS are presented, and also compared with a number of practical devices. Finally, the importance of l/f noise (f is the frequency) in limiting the low frequency performance of SQUIDS is discussed

  4. The Effect of Pleistocene Climate Fluctuations on Distribution of European Abalone (Haliotis tuberculata), Revealed by Combined Mitochondrial and Nuclear Marker Analyses.

    Science.gov (United States)

    Roussel, Valérie; Van Wormhoudt, Alain

    2017-04-01

    The genetic differentiation among the populations of the European abalone Haliotis tuberculata was investigated using different markers to better understand the evolutionary history and exchanges between populations. Three markers were used: mitochondrial cytochrome oxidase I (COI), the sperm lysin nuclear gene, and eight nuclear microsatellites. These markers present different characteristics concerning mutation rate and inheritance, which provided complementary information about abalone history and gene diversity. Genetic diversity and relationships among subspecies were calculated from a sample of approximately 500 individuals, collected from 17 different locations in the north-eastern Atlantic Ocean, Macaronesia, and Mediterranean Sea. COI marker was used to explore the phylogeny of the species with a network analysis and two phylogenetic methods. The analysis revealed 18 major haplotypes grouped into two distinct clades with a pairwise sequence divergence up to 3.5 %. These clades do not correspond to subspecies but revealed many contacts along Atlantic coast during the Pleistocene interglaciations. The sperm lysin gene analysis separated two different subtaxa: one associated to Macaronesian islands, and the other to all other populations. Moreover, a small population of the northern subtaxon was isolated in the Adriatic Sea-probably before the separation of the two lineages-and evolved independently. Microsatellites were analyzed by different genetics methods, including the Bayesian clustering method and migration patterns analysis. It revealed genetically distinct microsatellite patterns among populations from Mediterranean Sea, Brittany and Normandy, Morocco, and Canary and Balearic islands. Gene flow is asymmetric among the regions; the Azores and the Canary Islands are particularly isolated and have low effective population sizes. Our results support the hypothesis that climate changes since the Pleistocene glaciations have played a major role in the

  5. Novel binding motif and new flexibility revealed by structural analyses of a pyruvate dehydrogenase-dihydrolipoyl acetyltransferase subcomplex from the Escherichia coli pyruvate dehydrogenase multienzyme complex.

    Science.gov (United States)

    Arjunan, Palaniappa; Wang, Junjie; Nemeria, Natalia S; Reynolds, Shelley; Brown, Ian; Chandrasekhar, Krishnamoorthy; Calero, Guillermo; Jordan, Frank; Furey, William

    2014-10-24

    The Escherichia coli pyruvate dehydrogenase multienzyme complex contains multiple copies of three enzymatic components, E1p, E2p, and E3, that sequentially carry out distinct steps in the overall reaction converting pyruvate to acetyl-CoA. Efficient functioning requires the enzymatic components to assemble into a large complex, the integrity of which is maintained by tethering of the displaced, peripheral E1p and E3 components to the E2p core through non-covalent binding. We here report the crystal structure of a subcomplex between E1p and an E2p didomain containing a hybrid lipoyl domain along with the peripheral subunit-binding domain responsible for tethering to the core. In the structure, a region at the N terminus of each subunit in the E1p homodimer previously unseen due to crystallographic disorder was observed, revealing a new folding motif involved in E1p-E2p didomain interactions, and an additional, unexpected, flexibility was discovered in the E1p-E2p didomain subcomplex, both of which probably have consequences in the overall multienzyme complex assembly. This represents the first structure of an E1p-E2p didomain subcomplex involving a homodimeric E1p, and the results may be applicable to a large range of complexes with homodimeric E1 components. Results of HD exchange mass spectrometric experiments using the intact, wild type 3-lipoyl E2p and E1p are consistent with the crystallographic data obtained from the E1p-E2p didomain subcomplex as well as with other biochemical and NMR data reported from our groups, confirming that our findings are applicable to the entire E1p-E2p assembly. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.

  6. Novel Binding Motif and New Flexibility Revealed by Structural Analyses of a Pyruvate Dehydrogenase-Dihydrolipoyl Acetyltransferase Subcomplex from the Escherichia coli Pyruvate Dehydrogenase Multienzyme Complex*

    Science.gov (United States)

    Arjunan, Palaniappa; Wang, Junjie; Nemeria, Natalia S.; Reynolds, Shelley; Brown, Ian; Chandrasekhar, Krishnamoorthy; Calero, Guillermo; Jordan, Frank; Furey, William

    2014-01-01

    The Escherichia coli pyruvate dehydrogenase multienzyme complex contains multiple copies of three enzymatic components, E1p, E2p, and E3, that sequentially carry out distinct steps in the overall reaction converting pyruvate to acetyl-CoA. Efficient functioning requires the enzymatic components to assemble into a large complex, the integrity of which is maintained by tethering of the displaced, peripheral E1p and E3 components to the E2p core through non-covalent binding. We here report the crystal structure of a subcomplex between E1p and an E2p didomain containing a hybrid lipoyl domain along with the peripheral subunit-binding domain responsible for tethering to the core. In the structure, a region at the N terminus of each subunit in the E1p homodimer previously unseen due to crystallographic disorder was observed, revealing a new folding motif involved in E1p-E2p didomain interactions, and an additional, unexpected, flexibility was discovered in the E1p-E2p didomain subcomplex, both of which probably have consequences in the overall multienzyme complex assembly. This represents the first structure of an E1p-E2p didomain subcomplex involving a homodimeric E1p, and the results may be applicable to a large range of complexes with homodimeric E1 components. Results of HD exchange mass spectrometric experiments using the intact, wild type 3-lipoyl E2p and E1p are consistent with the crystallographic data obtained from the E1p-E2p didomain subcomplex as well as with other biochemical and NMR data reported from our groups, confirming that our findings are applicable to the entire E1p-E2p assembly. PMID:25210042

  7. Flexibility and size heterogeneity of the LH1 light harvesting complex revealed by atomic force microscopy - Functional significance for bacterial photosynthesis

    NARCIS (Netherlands)

    Bahatyrova, S.; Frese, R.N.; van der Werf, K.O.; Otto, C.; Hunter, C.N.; Olsen, J.D.

    2004-01-01

    Previous electron microscopic studies of bacterial RC-LH1 complexes demonstrated both circular and elliptical conformations of the LH1 ring, and this implied flexibility has been suggested to allow passage of quinol from the Q

  8. Fluctuations in quantum chaos

    International Nuclear Information System (INIS)

    Casati, G.; Chirikov, B.V.

    1996-01-01

    Various fluctuations in quantum systems with discrete spectrum are discussed, including recent unpublished results. Open questions and unexplained peculiarities of quantum fluctuations are formulated [ru

  9. Flexible Bronchoscopy.

    Science.gov (United States)

    Miller, Russell J; Casal, Roberto F; Lazarus, Donald R; Ost, David E; Eapen, George A

    2018-03-01

    Flexible bronchoscopy has changed the course of pulmonary medicine. As technology advances, the role of the flexible bronchoscope for both diagnostic and therapeutic indications is continually expanding. This article reviews the historical development of the flexible bronchoscopy, fundamental uses of the flexible bronchoscope as a tool to examine the central airways and obtain diagnostic tissue, and the indications, complications, and contraindications to flexible bronchoscopy. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. On flexibility

    OpenAIRE

    Weiss, Christoph R.; Briglauer, Wolfgang

    2000-01-01

    By building on theoretical work by Mills and Schumann (1985) and Ungern-Sternberg (1990) this paper provides evidence on the determinants of two dimensions of flexibility, the flexibility in adjusting aggregate output over time (tactical flexibility) as well as the ability to switch quickly between products (operational flexibility). Econometric analysis of a sample of 40.000 farms in Upper-Austria for the period 1980 to 1990 suggests that larger full-time farms operated by younger, better ed...

  11. Prevention of pulsations caused by flexible risers

    NARCIS (Netherlands)

    Belfroid S.P.C; Golliard, J.; Korst, H.J.C.

    2013-01-01

    In the last few decades, flexible risers have increasingly been used in the offshore oil and gas industry. In gas applications these risers can generate high amplitude tonal pressure fluctuations when the gas velocity reaches a threshold value. The resulting pressure fluctuations can then cause high

  12. Sources of Macroeconomic Fluctuations in MENA Countries

    OpenAIRE

    Balcilar, Mehmet; Bagzibagli, Kemal

    2010-01-01

    A close examination of the MENA region economies reveals a number of fundamental sources of macroeconomic fluctuations. These include economic factors such as exchange rate instability, large public debt, current account deficits, and escalation of inflation. The political factors such as government instability, corruption, bureaucracy, and internal conflicts also are major sources of macroeconomic instability. Thus, the sources of macroeconomic fluctuations in these countri...

  13. Fluctuations and Photons

    International Nuclear Information System (INIS)

    Gupta, Sourendu

    2007-01-01

    In this talk I discuss measures of fluctuations, especially those leading to the proof that the quark gluon plasma indeed contains quarks. I discuss the quark mass dependence of the critical end point of QCD. Then I discuss probes of the QCD critical point. Non-gaussian behaviour of event-to-event fluctuations of conserved quantum numbers is one such probe. Another is due to the coupling of fluctuations in baryon number and electrical charge, giving rise to long range random fluctuations of local charge density which relax slowly. These fluctuations can scatter photons, giving rise to critical opalescence

  14. Fluctuations and Photons

    Science.gov (United States)

    Gupta, Sourendu

    2007-02-01

    In this talk I discuss measures of fluctuations, especially those leading to the proof that the quark gluon plasma indeed contains quarks. I discuss the quark mass dependence of the critical end point of QCD. Then I discuss probes of the QCD critical point. Non-gaussian behaviour of event-to-event fluctuations of conserved quantum numbers is one such probe. Another is due to the coupling of fluctuations in baryon number and electrical charge, giving rise to long range random fluctuations of local charge density which relax slowly. These fluctuations can scatter photons, giving rise to critical opalescence.

  15. Fluctuations and Photons

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Sourendu [Department of Theoretical Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India)

    2007-02-15

    In this talk I discuss measures of fluctuations, especially those leading to the proof that the quark gluon plasma indeed contains quarks. I discuss the quark mass dependence of the critical end point of QCD. Then I discuss probes of the QCD critical point. Non-gaussian behaviour of event-to-event fluctuations of conserved quantum numbers is one such probe. Another is due to the coupling of fluctuations in baryon number and electrical charge, giving rise to long range random fluctuations of local charge density which relax slowly. These fluctuations can scatter photons, giving rise to critical opalescence.

  16. Conflicting flexibility

    NARCIS (Netherlands)

    De Jong, P.; Schaap, A.

    2011-01-01

    New buildings are designed for first users. For a sustainable approach there are many advantages in designing in flexibility and adjustability in order to enable and facilitate the other sequential users. For the first investor this flexibility is translated into improved exit values due to

  17. Fluctuation dynamics in geoelectrical data: an investigation by using multifractal detrended fluctuation analysis

    International Nuclear Information System (INIS)

    Telesca, Luciano; Colangelo, Gerardo; Lapenna, Vincenzo; Macchiato, Maria

    2004-01-01

    We analyzed fluctuations in the time dynamics of nonstationary geoelectrical data, recorded in a seismic area of southern Italy, by means of the multifractal detrended fluctuation analysis (MF-DFA). The multifractal character of the signal depends mostly on the different long-range properties for small and large fluctuations. The time variation of indices, denoting the departure from monofractal behaviour, reveals an enhancement of the multifractality of the signal prior seismic occurrences

  18. Empowering Variable Renewables - Options for Flexible Electricity Systems

    Energy Technology Data Exchange (ETDEWEB)

    Chandler, Hugo [Renewable Energy Unit, International Energy Agency, Paris (France)

    2008-07-01

    A flexible electricity system is one that can respond reliably, and rapidly, to large fluctuations in supply and demand. Flexibility is already present in all power systems, in order to manage fluctuations in demand, and it is crucial for high performance and economic and reliable operation. This paper looks at measures to increase flexibility. but careful cost/benefit analysis is essential, and specific national and regional circumstances will influence the choice of option(s).

  19. Germ cell regeneration-mediated, enhanced mutagenesis in the ascidian Ciona intestinalis reveals flexible germ cell formation from different somatic cells.

    Science.gov (United States)

    Yoshida, Keita; Hozumi, Akiko; Treen, Nicholas; Sakuma, Tetsushi; Yamamoto, Takashi; Shirae-Kurabayashi, Maki; Sasakura, Yasunori

    2017-03-15

    The ascidian Ciona intestinalis has a high regeneration capacity that enables the regeneration of artificially removed primordial germ cells (PGCs) from somatic cells. We utilized PGC regeneration to establish efficient methods of germ line mutagenesis with transcription activator-like effector nucleases (TALENs). When PGCs were artificially removed from animals in which a TALEN pair was expressed, somatic cells harboring mutations in the target gene were converted into germ cells, this germ cell population exhibited higher mutation rates than animals not subjected to PGC removal. PGC regeneration enables us to use TALEN expression vectors of specific somatic tissues for germ cell mutagenesis. Unexpectedly, cis elements for epidermis, neural tissue and muscle could be used for germ cell mutagenesis, indicating there are multiple sources of regenerated PGCs, suggesting a flexibility of differentiated Ciona somatic cells to regain totipotency. Sperm and eggs of a single hermaphroditic, PGC regenerated animal typically have different mutations, suggesting they arise from different cells. PGCs can be generated from somatic cells even though the maternal PGCs are not removed, suggesting that the PGC regeneration is not solely an artificial event but could have an endogenous function in Ciona. This study provides a technical innovation in the genome-editing methods, including easy establishment of mutant lines. Moreover, this study suggests cellular mechanisms and the potential evolutionary significance of PGC regeneration in Ciona. Copyright © 2017 Elsevier Inc. All rights reserved.

  20. Fluctuations and stability in the Advanced Toroidal Facility (ATF) torsatron

    International Nuclear Information System (INIS)

    Harris, J.H.; Charlton, L.A.; Bell, J.D.; Bigelow, T.S.; Carreras, B.A.; Colchin, R.J.; Crume, E.C.; Dominguez, N.; Dunlap, J.L.; Dyer, G.R.; England, A.C.; Glowienka, J.C.; Hillis, D.L.; Hiroe, S.; Horton, L.D.; Howe, H.C.; Isler, R.C.; Jernigan, T.C.; Leboeuf, J.N.; Lee, D.K.; Lynch, V.E.; Lyon, J.F.; Menon, M.M.; Murakami, M.; Rasmussen, D.A.; Uckan, T.; Wilgen, J.B.; Wing, W.R.; Bell, G.L.; Crocker, N.A.; Hanson, G.R.; Thomas, C.E.; Wade, M.R.; Ritz, C.P.

    1990-01-01

    We present the results of experimental and theoretical studies of fluctuations and instabilities in the ATF torsatron, a type of stellarator. Measurements of globally coherent magnetic fluctuations in high-β plasmas with narrow pressure profiles produced by a field error show evidence of self-stabilization ('second stability'); the trends are compatible with theoretical analysis of self-stabilization of resistive curvature-driven instabilities, but there are discrepancies between the absolute experimental and theoretical fluctuation amplitudes. Fluctuation measurements in plasma with broad pressure profiles reveal new phenomena--specifically, toroidally localized magnetic fluctuations, whose amplitudes increase with plasma pressure, and coherent density fluctuations with significant radial width

  1. Model Studies of the Histidine-Tyrosine Cross-Link in Cytochrome c Oxidase Reveal the Flexible Substituent Effect of the Imidazole Moiety

    Science.gov (United States)

    Pratt, Derek A.; Pesavento, Russell P.; van der Donk, Wilfred A.

    2010-01-01

    Experimental and theoretical studies were carried out to interrogate the effect of an imidazole substituent in each of the ortho, meta, and para positions on the pKa, E°, and O–H BDE of phenol. The results reveal that imidazole substitution lowers the pKa of phenol and increases the E° of phenoxide due to its σ-electron withdrawing ability (σp− = +0.21, σm− = +0.45) but decreases the O–H BDE and E° of phenol due to its σ-electron-donating ability (σp+ = −0.45). PMID:15957934

  2. Single molecule detection, thermal fluctuation and life

    Science.gov (United States)

    YANAGIDA, Toshio; ISHII, Yoshiharu

    2017-01-01

    Single molecule detection has contributed to our understanding of the unique mechanisms of life. Unlike artificial man-made machines, biological molecular machines integrate thermal noises rather than avoid them. For example, single molecule detection has demonstrated that myosin motors undergo biased Brownian motion for stepwise movement and that single protein molecules spontaneously change their conformation, for switching to interactions with other proteins, in response to thermal fluctuation. Thus, molecular machines have flexibility and efficiency not seen in artificial machines. PMID:28190869

  3. Superconductivity and spin fluctuations

    International Nuclear Information System (INIS)

    Scalapino, D.J.

    1999-01-01

    The organizers of the Memorial Session for Herman Rietschel asked that the author review some of the history of the interplay of superconductivity and spin fluctuations. Initially, Berk and Schrieffer showed how paramagnon spin fluctuations could suppress superconductivity in nearly-ferromagnetic materials. Following this, Rietschel and various co-workers wrote a number of papers in which they investigated the role of spin fluctuations in reducing the Tc of various electron-phonon superconductors. Paramagnon spin fluctuations are also believed to provide the p-wave pairing mechanism responsible for the superfluid phases of 3 He. More recently, antiferromagnetic spin fluctuations have been proposed as the mechanism for d-wave pairing in the heavy-fermion superconductors and in some organic materials as well as possibly the high-Tc cuprates. Here the author will review some of this early history and discuss some of the things he has learned more recently from numerical simulations

  4. Molecular Dynamics Simulations Reveal the Conformational Flexibility of Lipid II and Its Loose Association with the Defensin Plectasin in the Staphylococcus aureus Membrane

    DEFF Research Database (Denmark)

    Witzke, Sarah; Petersen, Michael; Carpenter, Timothy S.

    2016-01-01

    dynamics simulation study of the conformational dynamics of Lipid II within a detailed model of the Staphylococcus aureus cell membrane. We show that Lipid II is able to adopt a range of conformations, even within the packed lipidic environment of the membrane. Our simulations also reveal dimerization...... the biosynthesis of the cell wall. Given the urgent need for development of novel antibiotics to counter the growing threat of bacterial infection resistance, it is imperative that a thorough molecular-level characterization of the molecules targeted by antibiotics be achieved. To this end, we present a molecular...... of Lipid II mediated by cations. In the presence of the defensin peptide plectasin, the conformational lability of Lipid II allows it to form loose complexes with the protein, via a number of different binding modes....

  5. A new crystal form of human tear lipocalin reveals high flexibility in the loop region and induced fit in the ligand cavity

    International Nuclear Information System (INIS)

    Breustedt, Daniel A.; Chatwell, Lorenz; Skerra, Arne

    2009-01-01

    The crystal structure of tear lipocalin determined in space group P2 1 revealed large structural deviations from the previously solved X-ray structure in space group C2, especially in the loop region and adjoining parts of the β-barrel which give rise to the ligand-binding site. These findings illustrate a novel mechanism for promiscuity in ligand recognition by the lipocalin protein family. Tear lipocalin (TLC) with the bound artificial ligand 1,4-butanediol has been crystallized in space group P2 1 with four protein molecules in the asymmetric unit and its X-ray structure has been solved at 2.6 Å resolution. TLC is a member of the lipocalin family that binds ligands with diverse chemical structures, such as fatty acids, phospholipids and cholesterol as well as microbial siderophores and the antibiotic rifampin. Previous X-ray structural analysis of apo TLC crystallized in space group C2 revealed a rather large bifurcated ligand pocket and a partially disordered loop region at the entrace to the cavity. Analysis of the P2 1 crystal form uncovered major conformational changes (i) in β-strands B, C and D, (ii) in loops 1, 2 and 4 at the open end of the β-barrel and (iii) in the extended C-terminal segment, which is attached to the β-barrel via a disulfide bridge. The structural comparison indicates high conformational plasticity of the loop region as well as of deeper parts of the ligand pocket, thus allowing adaptation to ligands that differ vastly in size and shape. This illustrates a mechanism for promiscuity in ligand recognition which may also be relevant for some other physiologically important members of the lipocalin protein family

  6. Integrated flexible capacity and inventory management under flexible capacity uncertainty

    OpenAIRE

    Paç, Mehmet Fazıl

    2006-01-01

    Cataloged from PDF version of article. In a manufacturing environment with volatile demand, inventory management can be coupled with dynamic capacity adjustments for handling the fluctuations more effectively. In this study we consider the integrated management of inventory and flexible capacity management under seasonal stochastic demand and uncertain labor supply. The capacity planning problem is investigated from the workforce planning perspective. We consider a manufactu...

  7. Conformational flexibility in the catalytic triad revealed by the high-resolution crystal structure of Streptomyces erythraeus trypsin in an unliganded state

    Energy Technology Data Exchange (ETDEWEB)

    Blankenship, Elise; Vukoti, Krishna [Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106 (United States); Miyagi, Masaru, E-mail: mxm356@cwru.edu [Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106 (United States); Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106 (United States); Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106 (United States); Lodowski, David T., E-mail: mxm356@cwru.edu [Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106 (United States); Case Western Reserve University, 10900 Euclid Avenue, Cleveland, OH 44106 (United States)

    2014-03-01

    This work reports the first sub-angstrom resolution structure of S. erythraeus trypsin. The detailed model of a prototypical serine protease at a catalytically relevant pH with an unoccupied active site is presented and is compared with other high-resolution serine protease structures. With more than 500 crystal structures determined, serine proteases make up greater than one-third of all proteases structurally examined to date, making them among the best biochemically and structurally characterized enzymes. Despite the numerous crystallographic and biochemical studies of trypsin and related serine proteases, there are still considerable shortcomings in the understanding of their catalytic mechanism. Streptomyces erythraeus trypsin (SET) does not exhibit autolysis and crystallizes readily at physiological pH; hence, it is well suited for structural studies aimed at extending the understanding of the catalytic mechanism of serine proteases. While X-ray crystallographic structures of this enzyme have been reported, no coordinates have ever been made available in the Protein Data Bank. Based on this, and observations on the extreme stability and unique properties of this particular trypsin, it was decided to crystallize it and determine its structure. Here, the first sub-angstrom resolution structure of an unmodified, unliganded trypsin crystallized at physiological pH is reported. Detailed structural analysis reveals the geometry and structural rigidity of the catalytic triad in the unoccupied active site and comparison to related serine proteases provides a context for interpretation of biochemical studies of catalytic mechanism and activity.

  8. Conformational flexibility in the catalytic triad revealed by the high-resolution crystal structure of Streptomyces erythraeus trypsin in an unliganded state

    International Nuclear Information System (INIS)

    Blankenship, Elise; Vukoti, Krishna; Miyagi, Masaru; Lodowski, David T.

    2014-01-01

    This work reports the first sub-angstrom resolution structure of S. erythraeus trypsin. The detailed model of a prototypical serine protease at a catalytically relevant pH with an unoccupied active site is presented and is compared with other high-resolution serine protease structures. With more than 500 crystal structures determined, serine proteases make up greater than one-third of all proteases structurally examined to date, making them among the best biochemically and structurally characterized enzymes. Despite the numerous crystallographic and biochemical studies of trypsin and related serine proteases, there are still considerable shortcomings in the understanding of their catalytic mechanism. Streptomyces erythraeus trypsin (SET) does not exhibit autolysis and crystallizes readily at physiological pH; hence, it is well suited for structural studies aimed at extending the understanding of the catalytic mechanism of serine proteases. While X-ray crystallographic structures of this enzyme have been reported, no coordinates have ever been made available in the Protein Data Bank. Based on this, and observations on the extreme stability and unique properties of this particular trypsin, it was decided to crystallize it and determine its structure. Here, the first sub-angstrom resolution structure of an unmodified, unliganded trypsin crystallized at physiological pH is reported. Detailed structural analysis reveals the geometry and structural rigidity of the catalytic triad in the unoccupied active site and comparison to related serine proteases provides a context for interpretation of biochemical studies of catalytic mechanism and activity

  9. Hadronic Correlations and Fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Koch, Volker

    2008-10-09

    We will provide a review of some of the physics which can be addressed by studying fluctuations and correlations in heavy ion collisions. We will discuss Lattice QCD results on fluctuations and correlations and will put them into context with observables which have been measured in heavy-ion collisions. Special attention will be given to the QCD critical point and the first order co-existence region, and we will discuss how the measurement of fluctuations and correlations can help in an experimental search for non-trivial structures in the QCD phase diagram.

  10. Quantum fluctuations and inflation

    International Nuclear Information System (INIS)

    Bardeen, J.M.; Bublik, G.J.

    1986-05-01

    We study the effect of quantum fluctuations on the roll-down rate of the inflation field in a semiclassical approximation; this is done by treating the inflation field as a classical random field. The quantum fluctuations are simulated by a noise term in the equation of motion. We consider two different inflationary scenarios (new and chaotic inflation) and find that the roll-down rate of the median value of the inflation field is increased by the quantum fluctuations. Non-linear effects may become important in the later stages of the inflationary regime. 8 refs., 2 figs

  11. Quantum fluctuations and inflation

    International Nuclear Information System (INIS)

    Bardeen, J.M.; Bublik, G.J.

    1987-01-01

    The authors study the effect of quantum fluctuations on the roll-down rate of the inflation field in a semiclassical approximation; this is done by treating the inflation field as a classical random field. The quantum fluctuations are simulated by a noise term in the equation of motion. Two different inflationary scenarios (new and chaotic inflation) are considered and it is found that the roll-down rate of the median value of the inflation field is increased by the quantum fluctuations. Non-linear effects may become important in the later stages of the inflationary regime. (author)

  12. Highly flexible and robust N-doped SiC nanoneedle field emitters

    KAUST Repository

    Chen, Shanliang

    2015-01-23

    Flexible field emission (FE) emitters, whose unique advantages are lightweight and conformable, promise to enable a wide range of technologies, such as roll-up flexible FE displays, e-papers and flexible light-emitting diodes. In this work, we demonstrate for the first time highly flexible SiC field emitters with low turn-on fields and excellent emission stabilities. n-Type SiC nanoneedles with ultra-sharp tips and tailored N-doping levels were synthesized via a catalyst-assisted pyrolysis process on carbon fabrics by controlling the gas mixture and cooling rate. The turn-on field, threshold field and current emission fluctuation of SiC nanoneedle emitters with an N-doping level of 7.58 at.% are 1.11 V μm-1, 1.55 V μm-1 and 8.1%, respectively, suggesting the best overall performance for such flexible field emitters. Furthermore, characterization of the FE properties under repeated bending cycles and different bending states reveal that the SiC field emitters are mechanically and electrically robust with unprecedentedly high flexibility and stabilities. These findings underscore the importance of concurrent morphology and composition controls in nanomaterial synthesis and establish SiC nanoneedles as the most promising candidate for flexible FE applications. © 2015 Nature Publishing Group All rights reserved.

  13. Highly flexible and robust N-doped SiC nanoneedle field emitters

    KAUST Repository

    Chen, Shanliang; Ying, Pengzhan; Wang, Lin; Wei, Guodong; Gao, Fengmei; Zheng, Jinju; Shang, Minhui; Yang, Zuobao; Yang, Weiyou; Wu, Tao

    2015-01-01

    Flexible field emission (FE) emitters, whose unique advantages are lightweight and conformable, promise to enable a wide range of technologies, such as roll-up flexible FE displays, e-papers and flexible light-emitting diodes. In this work, we demonstrate for the first time highly flexible SiC field emitters with low turn-on fields and excellent emission stabilities. n-Type SiC nanoneedles with ultra-sharp tips and tailored N-doping levels were synthesized via a catalyst-assisted pyrolysis process on carbon fabrics by controlling the gas mixture and cooling rate. The turn-on field, threshold field and current emission fluctuation of SiC nanoneedle emitters with an N-doping level of 7.58 at.% are 1.11 V μm-1, 1.55 V μm-1 and 8.1%, respectively, suggesting the best overall performance for such flexible field emitters. Furthermore, characterization of the FE properties under repeated bending cycles and different bending states reveal that the SiC field emitters are mechanically and electrically robust with unprecedentedly high flexibility and stabilities. These findings underscore the importance of concurrent morphology and composition controls in nanomaterial synthesis and establish SiC nanoneedles as the most promising candidate for flexible FE applications. © 2015 Nature Publishing Group All rights reserved.

  14. Fluorescence fluctuation spectroscopy (FFS)

    CERN Document Server

    Tetin, Sergey

    2012-01-01

    This new volume of Methods in Enzymology continues the legacy of this premier serial with quality chapters authored by leaders in the field. This volume covers fluorescence fluctuation spectroscopy and includes chapters on such topics as Förster resonance energy transfer (fret) with fluctuation algorithms, protein corona on nanoparticles by FCS, and FFS approaches to the study of receptors in live cells. Continues the legacy of this premier serial with quality chapters authored by leaders in the field Covers fluorescence fluctuation spectroscopy Contains chapters on such topics as Förster resonance energy transfer (fret) with fluctuation algorithms, protein corona on nanoparticles by FCS, and FFS approaches to the study of receptors in live cells.

  15. Fully Quantum Fluctuation Theorems

    Science.gov (United States)

    Åberg, Johan

    2018-02-01

    Systems that are driven out of thermal equilibrium typically dissipate random quantities of energy on microscopic scales. Crooks fluctuation theorem relates the distribution of these random work costs to the corresponding distribution for the reverse process. By an analysis that explicitly incorporates the energy reservoir that donates the energy and the control system that implements the dynamic, we obtain a quantum generalization of Crooks theorem that not only includes the energy changes in the reservoir but also the full description of its evolution, including coherences. Moreover, this approach opens up the possibility for generalizations of the concept of fluctuation relations. Here, we introduce "conditional" fluctuation relations that are applicable to nonequilibrium systems, as well as approximate fluctuation relations that allow for the analysis of autonomous evolution generated by global time-independent Hamiltonians. We furthermore extend these notions to Markovian master equations, implicitly modeling the influence of the heat bath.

  16. Workplace flexibility.

    Science.gov (United States)

    Scordato, C; Harris, J

    1990-01-01

    Whether your organization is in a growth pattern or downsizing, you are probably facing change. To gain some insight into your options, here is an in-depth look at the problems and benefits of some flexible work arrangements from a just published study by Catalyst.

  17. Flexibility conflict?

    NARCIS (Netherlands)

    Delsen, L.W.M.; Bauer, F.; Groß, H.; Sieglen, G.

    2002-01-01

    The chapter deals with the presupposed conflict of interests between employers and employees resulting from a decoupling of operating hours and working times. It starts from the notion that both long operating hours and flexibility are relative concepts. As there is some discretion, the ultimate

  18. Balancing energy flexibilities through aggregation

    DEFF Research Database (Denmark)

    Valsomatzis, Emmanouil; Hose, Katja; Pedersen, Torben Bach

    2014-01-01

    One of the main goals of recent developments in the Smart Grid area is to increase the use of renewable energy sources. These sources are characterized by energy fluctuations that might lead to energy imbalances and congestions in the electricity grid. Exploiting inherent flexibilities, which exist...... in both energy production and consumption, is the key to solving these problems. Flexibilities can be expressed as flex-offers, which due to their high number need to be aggregated to reduce the complexity of energy scheduling. In this paper, we discuss balance aggregation techniques that already during...... aggregation aim at balancing flexibilities in production and consumption to reduce the probability of congestions and reduce the complexity of scheduling. We present results of our extensive experiments....

  19. Flexible licensing

    Directory of Open Access Journals (Sweden)

    Martyn Jansen

    2012-07-01

    Full Text Available The case is presented for a more flexible approach to licensing online library resources. Today's distributed education environment creates pressure for UK higher and further education institutions (HEI/FEIs to form partnerships and to develop educational products and roll them out across the globe. Online library resources are a key component of distributed education and yet existing licensing agreements struggle to keep pace with the increasing range of users and purposes for which they are required. This article describes the process of developing a flexible approach to licensing and proposes a new model licence for online library resources which has the adaptability needed in this new global educational landscape. These ideas have been presented and discussed at various workshops across Eduserv's and JISC Collections' higher education and publisher communities, and further consultation is ongoing.

  20. An Efficient Null Model for Conformational Fluctuations in Proteins

    DEFF Research Database (Denmark)

    Harder, Tim Philipp; Borg, Mikael; Bottaro, Sandro

    2012-01-01

    Protein dynamics play a crucial role in function, catalytic activity, and pathogenesis. Consequently, there is great interest in computational methods that probe the conformational fluctuations of a protein. However, molecular dynamics simulations are computationally costly and therefore are often...... limited to comparatively short timescales. TYPHON is a probabilistic method to explore the conformational space of proteins under the guidance of a sophisticated probabilistic model of local structure and a given set of restraints that represent nonlocal interactions, such as hydrogen bonds or disulfide...... on conformational fluctuations that is in correspondence with experimental measurements. TYPHON provides a flexible, yet computationally efficient, method to explore possible conformational fluctuations in proteins....

  1. Universal mesoscopic conductance fluctuations

    International Nuclear Information System (INIS)

    Evangelou, S.N.

    1992-01-01

    The theory of conductance fluctuations in disordered metallic systems with size large compared to the mean free path of the electron but small compared to localization length is considered. It is demonstrates that fluctuations have an universal character and are due to repulsion between levels and spectral rigidity. The basic fluctuation measures for the energy spectrum in the mesoscopic regime of disordered systems are consistent with the Gaussian random matrix ensemble predictions. Although our disordered electron random matrix ensemble does not belong to the Gaussian ensemble the two ensembles turn out to be essentially similar. The level repulsion and the spectral rigidity found in nuclear spectra should also be observed in the metallic regime of Anderson localization. 7 refs. (orig.)

  2. Spin fluctuations and the

    Directory of Open Access Journals (Sweden)

    V.M. Loktev

    2008-09-01

    Full Text Available We analyze the spectral properties of a phenomenological model for a weakly doped two-dimensional antiferromagnet, in which the carriers move within one of the two sublattices where they were introduced. Such a constraint results in the free carrier spectra with the maxima at k=(± π/2 , ± π/2 observed in some cuprates. We consider the spectral properties of the model by taking into account fluctuations of the spins in the antiferromagnetic background. We show that such fluctuations lead to a non-pole-like structure of the single-hole Green's function and these fluctuations can be responsible for some anomalous "strange metal" properties of underdoped cuprates in the nonsuperconducting regime.

  3. The fluctuating gap model

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Xiaobin

    2011-01-15

    The quasi-one-dimensional systems exhibit some unusual phenomenon, such as the Peierls instability, the pseudogap phenomena and the absence of a Fermi-Dirac distribution function line shape in the photoemission spectroscopy. Ever since the discovery of materials with highly anisotropic properties, it has been recognized that fluctuations play an important role above the three-dimensional phase transition. This regime where the precursor fluctuations are presented can be described by the so called fluctuating gap model (FGM) which was derived from the Froehlich Hamiltonian to study the low energy physics of the one-dimensional electron-phonon system. Not only is the FGM of great interest in the context of quasi-one-dimensional materials, liquid metal and spin waves above T{sub c} in ferromagnets, but also in the semiclassical approximation of superconductivity, it is possible to replace the original three-dimensional problem by a directional average over effectively one-dimensional problem which in the weak coupling limit is described by the FGM. In this work, we investigate the FGM in a wide temperature range with different statistics of the order parameter fluctuations. We derive a formally exact solution to this problem and calculate the density of states, the spectral function and the optical conductivity. In our calculation, we show that a Dyson singularity appears in the low energy density of states for Gaussian fluctuations in the commensurate case. In the incommensurate case, there is no such kind of singularity, and the zero frequency density of states varies differently as a function of the correlation lengths for different statistics of the order parameter fluctuations. Using the density of states we calculated with non-Gaussian order parameter fluctuations, we are able to calculate the static spin susceptibility which agrees with the experimental data very well. In the calculation of the spectral functions, we show that as the correlation increases, the

  4. The fluctuating gap model

    International Nuclear Information System (INIS)

    Cao, Xiaobin

    2011-01-01

    The quasi-one-dimensional systems exhibit some unusual phenomenon, such as the Peierls instability, the pseudogap phenomena and the absence of a Fermi-Dirac distribution function line shape in the photoemission spectroscopy. Ever since the discovery of materials with highly anisotropic properties, it has been recognized that fluctuations play an important role above the three-dimensional phase transition. This regime where the precursor fluctuations are presented can be described by the so called fluctuating gap model (FGM) which was derived from the Froehlich Hamiltonian to study the low energy physics of the one-dimensional electron-phonon system. Not only is the FGM of great interest in the context of quasi-one-dimensional materials, liquid metal and spin waves above T c in ferromagnets, but also in the semiclassical approximation of superconductivity, it is possible to replace the original three-dimensional problem by a directional average over effectively one-dimensional problem which in the weak coupling limit is described by the FGM. In this work, we investigate the FGM in a wide temperature range with different statistics of the order parameter fluctuations. We derive a formally exact solution to this problem and calculate the density of states, the spectral function and the optical conductivity. In our calculation, we show that a Dyson singularity appears in the low energy density of states for Gaussian fluctuations in the commensurate case. In the incommensurate case, there is no such kind of singularity, and the zero frequency density of states varies differently as a function of the correlation lengths for different statistics of the order parameter fluctuations. Using the density of states we calculated with non-Gaussian order parameter fluctuations, we are able to calculate the static spin susceptibility which agrees with the experimental data very well. In the calculation of the spectral functions, we show that as the correlation increases, the quasi

  5. Flexible Consumption

    DEFF Research Database (Denmark)

    Holm Jacobsen, Peter; Pallesen, Trine

    This report presents the first findings from our qualitative study of consumer behaviour vis-à-vis flexible consumption. The main of objective of this report is to present our first round of data from Bornholm, and to assist the design of products/services designed in WP6. In the report, we adopt...... the perspective of the consumer: what does living in a demand response setup look like to participants – and what kinds of behaviour and interest motivate – and emerge from – their participation in EcoGrid 2.0....

  6. Flexible Capitalism

    DEFF Research Database (Denmark)

    Approaching “work” as at heart a practice of exchange, this volume explores sociality in work environments marked by the kind of structural changes that have come to define contemporary “flexible” capitalism. It introduces anthropological exchange theory to a wider readership, and shows how...... the perspective offers new ways to enquire about the flexible capitalism’s social dimensions. The essays contribute to a trans-disciplinary scholarship on contemporary economic practice and change by documenting how, across diverse settings, “gift-like” socialities proliferate, and even sustain the intensified...

  7. Fluctuating Asymmetry and Intelligence

    Science.gov (United States)

    Bates, Timothy C.

    2007-01-01

    The general factor of mental ability ("g") may reflect general biological fitness. If so, "g"-loaded measures such as Raven's progressive matrices should be related to morphological measures of fitness such as fluctuating asymmetry (FA: left-right asymmetry of a set of typically left-right symmetrical body traits such as finger…

  8. Flexible nanovectors

    International Nuclear Information System (INIS)

    Pugno, Nicola M

    2008-01-01

    In this paper we show that the control of adhesion in highly flexible (a property that could be crucial for smart drug delivery but which is still ignored in the literature) nanovectors can help in smartly targeting and delivering the drug. The existence of and the conditions for activating and controlling a super-adhesive state are addressed. Even if such a state has never been observed in nanovectors, our calculations, as well as observations in spiders and geckos, suggest its existence and feasible control. Control of the competition between the drag and the adhesive force is exploited to improve the targeting ability and a hierarchical model is applied to describe a real vasculature. The high flexibility of the nanovector is used to smartly deliver the drug only during adhesion by nanopumping or, as a limiting case, by the new concept of 'adhesion induced nanovector implosion'; a liquid drop analogy is utilized for the calculations. Fast (pumping) and slow (diffusion) drug deliveries can thus be separately controlled by controlling the size and shape of the nanovector. Multiple stage nanovectors are also briefly discussed, mimicking aerospace vector strategies.

  9. Flexible nanovectors

    Science.gov (United States)

    Pugno, Nicola M.

    2008-11-01

    In this paper we show that the control of adhesion in highly flexible (a property that could be crucial for smart drug delivery but which is still ignored in the literature) nanovectors can help in smartly targeting and delivering the drug. The existence of and the conditions for activating and controlling a super-adhesive state are addressed. Even if such a state has never been observed in nanovectors, our calculations, as well as observations in spiders and geckos, suggest its existence and feasible control. Control of the competition between the drag and the adhesive force is exploited to improve the targeting ability and a hierarchical model is applied to describe a real vasculature. The high flexibility of the nanovector is used to smartly deliver the drug only during adhesion by nanopumping or, as a limiting case, by the new concept of 'adhesion induced nanovector implosion'; a liquid drop analogy is utilized for the calculations. Fast (pumping) and slow (diffusion) drug deliveries can thus be separately controlled by controlling the size and shape of the nanovector. Multiple stage nanovectors are also briefly discussed, mimicking aerospace vector strategies.

  10. Determinants of flexible work arrangements

    OpenAIRE

    Sarbu, Miruna

    2014-01-01

    Flexible work arrangements such as allowing employees to work at home are used in firms, especially since information and communication technologies have become so widespread. Using individual-level data from 10,884 German employees, this paper analyses the determinants of working at home as a form of flexible work arrangements. The analysis is based on descriptive analyses and a discrete choice model using a probit estimation approach. The results reveal that men have a higher...

  11. Entropic fluctuations in DNA sequences

    Science.gov (United States)

    Thanos, Dimitrios; Li, Wentian; Provata, Astero

    2018-03-01

    The Local Shannon Entropy (LSE) in blocks is used as a complexity measure to study the information fluctuations along DNA sequences. The LSE of a DNA block maps the local base arrangement information to a single numerical value. It is shown that despite this reduction of information, LSE allows to extract meaningful information related to the detection of repetitive sequences in whole chromosomes and is useful in finding evolutionary differences between organisms. More specifically, large regions of tandem repeats, such as centromeres, can be detected based on their low LSE fluctuations along the chromosome. Furthermore, an empirical investigation of the appropriate block sizes is provided and the relationship of LSE properties with the structure of the underlying repetitive units is revealed by using both computational and mathematical methods. Sequence similarity between the genomic DNA of closely related species also leads to similar LSE values at the orthologous regions. As an application, the LSE covariance function is used to measure the evolutionary distance between several primate genomes.

  12. Critical Fluctuations in Spatial Complex Networks

    Science.gov (United States)

    Bradde, Serena; Caccioli, Fabio; Dall'Asta, Luca; Bianconi, Ginestra

    2010-05-01

    An anomalous mean-field solution is known to capture the nontrivial phase diagram of the Ising model in annealed complex networks. Nevertheless, the critical fluctuations in random complex networks remain mean field. Here we show that a breakdown of this scenario can be obtained when complex networks are embedded in geometrical spaces. Through the analysis of the Ising model on annealed spatial networks, we reveal, in particular, the spectral properties of networks responsible for critical fluctuations and we generalize the Ginsburg criterion to complex topologies.

  13. Fluctuations in quantum devices

    Directory of Open Access Journals (Sweden)

    H.Haken

    2004-01-01

    Full Text Available Logical gates can be formalized by Boolean algebra whose elementary operations can be realized by devices that employ the interactions of macroscopic numbers of elementary excitations such as electrons, holes, photons etc. With increasing miniaturization to the nano scale and below, quantum fluctuations become important and can no longer be ignored. Based on Heisenberg equations of motion for the creation and annihilation operators of elementary excitations, I determine the noise sources of composite quantum systems.

  14. Fuel Cells for Balancing Fluctuation Renewable Energy Sources

    DEFF Research Database (Denmark)

    Mathiesen, Brian Vad

    2007-01-01

    In the perspective of using fuel cells for integration of fluctuating renewable energy the SOFCs are the most promising. These cells have the advantage of significantly higher electricity efficiency than competing technologies and fuel flexibility. Fuel cells in general also have the advantage of...... with hydrogen production or electric cars, and on the other hand using biomass and bio fuels [11]. Fuel cells can have an important role in these future energy systems.......In the perspective of using fuel cells for integration of fluctuating renewable energy the SOFCs are the most promising. These cells have the advantage of significantly higher electricity efficiency than competing technologies and fuel flexibility. Fuel cells in general also have the advantage...... flexibility, such as SOFCs, heat pumps and heat storage technologies are more important than storing electricity as hydrogen via electrolysis in energy systems with high amounts of wind [12]. Unnecessary energy conversions should be avoided. However in future energy systems with wind providing more than 50...

  15. Fluctuations and Instability in Sedimentation

    KAUST Repository

    Guazzelli, É lisabeth; Hinch, John

    2011-01-01

    This review concentrates on the fluctuations of the velocities of sedimenting spheres, and on the structural instability of a suspension of settling fibers. For many years, theoretical estimates and numerical simulations predicted the fluctuations

  16. Flexibility, but for whom? : A new approach to examining labour market flexibility across Europe using company level data

    OpenAIRE

    Chung, Heejung

    2006-01-01

    Labour market flexibility continues to be one of the key issues in the reform of labour markets in welfare states. The way in which various countries adapt to this need differs according to their institutions and prevailing strategies. Despite the vast numbers of studies addressing this issue, labour market flexibility has been examined predominantly by concentrating on the arrangements that firms adopt to adjust to market fluctuations. Thus flexibility arrangements are perceived to exist onl...

  17. Fluctuations in Schottky barrier heights

    International Nuclear Information System (INIS)

    Mahan, G.D.

    1984-01-01

    A double Schottky barrier is often formed at the grain boundary in polycrystalline semiconductors. The barrier height is shown to fluctuate in value due to the random nature of the impurity positions. The magnitude of the fluctuations is 0.1 eV, and the fluctuations cause the barrier height measured by capacitance to differ from the one measured by electrical conductivity

  18. Flexible firm

    DEFF Research Database (Denmark)

    Krause-Jensen, Jakob

    This book investigates how company values are communicated and collective identity articulated throught the use of such concepts as 'culture', 'fundamental values', and 'corporate religion', as well as how employees negotiate these ideas in their working lives. As the book reveals, the the work w...... with the official values, meant to create cohesion and solidarity aming the employees, came to engender a split between the staff and the other parts of the company.......This book investigates how company values are communicated and collective identity articulated throught the use of such concepts as 'culture', 'fundamental values', and 'corporate religion', as well as how employees negotiate these ideas in their working lives. As the book reveals, the the work...

  19. Strain fluctuations and elastic constants

    Energy Technology Data Exchange (ETDEWEB)

    Parrinello, M.; Rahman, A.

    1982-03-01

    It is shown that the elastic strain fluctuations are a direct measure of elastic compliances in a general anisotropic medium; depending on the ensemble in which the fluctuation is measured either the isothermal or the adiabatic compliances are obtained. These fluctuations can now be calculated in a constant enthalpy and pressure, and hence, constant entropy, ensemble due to recent develpments in the molecular dynamics techniques. A calculation for a Ni single crystal under uniform uniaxial 100 tensile or compressive load is presented as an illustration of the relationships derived between various strain fluctuations and the elastic modulii. The Born stability criteria and the behavior of strain fluctuations are shown to be related.

  20. Gambling with Superconducting Fluctuations

    Science.gov (United States)

    Foltyn, Marek; Zgirski, Maciej

    2015-08-01

    Josephson junctions and superconducting nanowires, when biased close to superconducting critical current, can switch to a nonzero voltage state by thermal or quantum fluctuations. The process is understood as an escape of a Brownian particle from a metastable state. Since this effect is fully stochastic, we propose to use it for generating random numbers. We present protocol for obtaining random numbers and test the experimentally harvested data for their fidelity. Our work is prerequisite for using the Josephson junction as a tool for stochastic (probabilistic) determination of physical parameters such as magnetic flux, temperature, and current.

  1. Fluctuations in the hadronization

    International Nuclear Information System (INIS)

    Bozek, P.; Ploszajaczak, M.

    1992-01-01

    The multiscaling in the fluctuations of the multiparticle distributions at small scales is studied. Similarly to the multiscaling effect, recently found in multifractal models, the dependence of the intermittency patterns on the low density cut-off in the cascade is analyzed. The effect changes the scaling behaviour and leads to stronger dependence of the scaled factorial moments on the resolution than the power law. This could be an explanation of the behaviour observed recently in the experimental 3-dimensional data. The multiscaling analysis allows to restore the universality in the processes with different cut-offs and could be used in the analysis of the experimental data. (author) 17 refs., 5 figs

  2. Flexible Electronics Research Facility

    Data.gov (United States)

    Federal Laboratory Consortium — The Flexible Electronics Research Facility designs, synthesizes, tests, and fabricates materials and devices compatible with flexible substrates for Army information...

  3. Fluctuation Relations for Currents

    Science.gov (United States)

    Sinitsyn, Nikolai; Akimov, Alexei; Chernyak, Vladimir; Chertkov, Michael

    2011-03-01

    We consider a non-equilibrium statistical system on a graph or a network. Identical particles are injected, interact with each other, traverse, and leave the graph in a stochastic manner described in terms of Poisson rates, possibly strongly dependent on time and instantaneous occupation numbers at the nodes of the graph. We show that the system demonstrates a profound statistical symmetry, leading to new Fluctuation Relations that originate from the supersymmetry and the principle of the geometric universality of currents rather than from the relations between probabilities of forward and reverse trajectories. NSF/ECCS-0925618, NSF/CHE-0808910 and DOE at LANL under Contract No. DE-AC52-06NA25396.

  4. Fluctuations in email size

    Science.gov (United States)

    Matsubara, Yoshitsugu; Musashi, Yasuo

    2017-12-01

    The purpose of this study is to explain fluctuations in email size. We have previously investigated the long-term correlations between email send requests and data flow in the system log of the primary staff email server at a university campus, finding that email size frequency follows a power-law distribution with two inflection points, and that the power-law property weakens the correlation of the data flow. However, the mechanism underlying this fluctuation is not completely understood. We collected new log data from both staff and students over six academic years and analyzed the frequency distribution thereof, focusing on the type of content contained in the emails. Furthermore, we obtained permission to collect "Content-Type" log data from the email headers. We therefore collected the staff log data from May 1, 2015 to July 31, 2015, creating two subdistributions. In this paper, we propose a model to explain these subdistributions, which follow log-normal-like distributions. In the log-normal-like model, email senders -consciously or unconsciously- regulate the size of new email sentences according to a normal distribution. The fitting of the model is acceptable for these subdistributions, and the model demonstrates power-law properties for large email sizes. An analysis of the length of new email sentences would be required for further discussion of our model; however, to protect user privacy at the participating organization, we left this analysis for future work. This study provides new knowledge on the properties of email sizes, and our model is expected to contribute to the decision on whether to establish upper size limits in the design of email services.

  5. Fluctuating Thermodynamics for Biological Processes

    Science.gov (United States)

    Ham, Sihyun

    Because biomolecular processes are largely under thermodynamic control, dynamic extension of thermodynamics is necessary to uncover the mechanisms and driving factors of fluctuating processes. The fluctuating thermodynamics technology presented in this talk offers a practical means for the thermodynamic characterization of conformational dynamics in biomolecules. The use of fluctuating thermodynamics has the potential to provide a comprehensive picture of fluctuating phenomena in diverse biological processes. Through the application of fluctuating thermodynamics, we provide a thermodynamic perspective on the misfolding and aggregation of the various proteins associated with human diseases. In this talk, I will present the detailed concepts and applications of the fluctuating thermodynamics technology for elucidating biological processes. This work was supported by Samsung Science and Technology Foundation under Project Number SSTF-BA1401-13.

  6. Big Bang or vacuum fluctuation

    International Nuclear Information System (INIS)

    Zel'dovich, Ya.B.

    1980-01-01

    Some general properties of vacuum fluctuations in quantum field theory are described. The connection between the ''energy dominance'' of the energy density of vacuum fluctuations in curved space-time and the presence of singularity is discussed. It is pointed out that a de-Sitter space-time (with the energy density of the vacuum fluctuations in the Einstein equations) that matches the expanding Friedman solution may describe the history of the Universe before the Big Bang. (P.L.)

  7. Mesoscale wind fluctuations over Danish waters

    Energy Technology Data Exchange (ETDEWEB)

    Vincent, C.L.

    2010-12-15

    Mesoscale wind fluctuations affect the large scale integration of wind power because they undermine the day-ahead predictability of wind speed and power production, and because they can result in large fluctuations in power generation that must be balanced using reserve power. Large fluctuations in generated power are a particular problem for offshore wind farms because the typically high concentration of turbines within a limited geographical area means that fluctuations can be correlated across large numbers of turbines. Furthermore, organised mesoscale structures that often form over water, such as convective rolls and cellular convection, have length scales of tens of kilometers, and can cause large wind fluctuations on a time scale of around an hour. This thesis is an exploration of the predictability of mesoscale wind fluctuations using observations from the world's first two large offshore wind farms - Horns Rev I in the North Sea, and Nysted in the Baltic Sea. The thesis begins with a climatological analysis of wind fluctuations on time scales of 1-10 hours at the two sites. A novel method for calculating conditional climatologies of spectral information is proposed, based on binning and averaging the time axis of the Hilbert spectrum. Results reveal clear patterns between wind fluctuations and locally observed meteorological conditions. The analysis is expanded by classifying wind fluctuations on time scales of 1-3 hours according to synoptic patterns, satellite pictures and wind classes. Results indicate that cold air outbreaks and open cellular convection are a significant contributor to mesoscale wind variability at Horns Rev. The predictability of mesoscale wind fluctuations is tested by implementing standard statistical models that relate local wind variability to parameters based on a large scale weather analysis. The models show some skill, but only achieve a 15% improvement on a persistence forecast. The possibility of explicitly modelling

  8. Thermodynamic theory of equilibrium fluctuations

    International Nuclear Information System (INIS)

    Mishin, Y.

    2015-01-01

    The postulational basis of classical thermodynamics has been expanded to incorporate equilibrium fluctuations. The main additional elements of the proposed thermodynamic theory are the concept of quasi-equilibrium states, a definition of non-equilibrium entropy, a fundamental equation of state in the entropy representation, and a fluctuation postulate describing the probability distribution of macroscopic parameters of an isolated system. Although these elements introduce a statistical component that does not exist in classical thermodynamics, the logical structure of the theory is different from that of statistical mechanics and represents an expanded version of thermodynamics. Based on this theory, we present a regular procedure for calculations of equilibrium fluctuations of extensive parameters, intensive parameters and densities in systems with any number of fluctuating parameters. The proposed fluctuation formalism is demonstrated by four applications: (1) derivation of the complete set of fluctuation relations for a simple fluid in three different ensembles; (2) fluctuations in finite-reservoir systems interpolating between the canonical and micro-canonical ensembles; (3) derivation of fluctuation relations for excess properties of grain boundaries in binary solid solutions, and (4) derivation of the grain boundary width distribution for pre-melted grain boundaries in alloys. The last two applications offer an efficient fluctuation-based approach to calculations of interface excess properties and extraction of the disjoining potential in pre-melted grain boundaries. Possible future extensions of the theory are outlined.

  9. Electronic zero-point fluctuation forces inside circuit components

    Science.gov (United States)

    Leonhardt, Ulf

    2018-01-01

    One of the most intriguing manifestations of quantum zero-point fluctuations are the van der Waals and Casimir forces, often associated with vacuum fluctuations of the electromagnetic field. We study generalized fluctuation potentials acting on internal degrees of freedom of components in electrical circuits. These electronic Casimir-like potentials are induced by the zero-point current fluctuations of any general conductive circuit. For realistic examples of an electromechanical capacitor and a superconducting qubit, our results reveal the possibility of tunable forces between the capacitor plates, or the level shifts of the qubit, respectively. Our analysis suggests an alternative route toward the exploration of Casimir-like fluctuation potentials, namely, by characterizing and measuring them as a function of parameters of the environment. These tunable potentials may be useful for future nanoelectromechanical and quantum technologies. PMID:29719863

  10. Electronic zero-point fluctuation forces inside circuit components.

    Science.gov (United States)

    Shahmoon, Ephraim; Leonhardt, Ulf

    2018-04-01

    One of the most intriguing manifestations of quantum zero-point fluctuations are the van der Waals and Casimir forces, often associated with vacuum fluctuations of the electromagnetic field. We study generalized fluctuation potentials acting on internal degrees of freedom of components in electrical circuits. These electronic Casimir-like potentials are induced by the zero-point current fluctuations of any general conductive circuit. For realistic examples of an electromechanical capacitor and a superconducting qubit, our results reveal the possibility of tunable forces between the capacitor plates, or the level shifts of the qubit, respectively. Our analysis suggests an alternative route toward the exploration of Casimir-like fluctuation potentials, namely, by characterizing and measuring them as a function of parameters of the environment. These tunable potentials may be useful for future nanoelectromechanical and quantum technologies.

  11. Molecular dynamics of CYP2D6 polymorphisms in the absence and presence of a mechanism-based inactivator reveals changes in local flexibility and dominant substrate access channels.

    Directory of Open Access Journals (Sweden)

    Parker W de Waal

    Full Text Available Cytochrome P450 enzymes (CYPs represent an important enzyme superfamily involved in metabolism of many endogenous and exogenous small molecules. CYP2D6 is responsible for ∼ 15% of CYP-mediated drug metabolism and exhibits large phenotypic diversity within CYPs with over 100 different allelic variants. Many of these variants lead to functional changes in enzyme activity and substrate selectivity. Herein, a molecular dynamics comparative analysis of four different variants of CYP2D6 was performed. The comparative analysis included simulations with and without SCH 66712, a ligand that is also a mechanism-based inactivator, in order to investigate the possible structural basis of CYP2D6 inactivation. Analysis of protein stability highlighted significantly altered flexibility in both proximal and distal residues from the variant residues. In the absence of SCH 66712, *34, *17-2, and *17-3 displayed more flexibility than *1, and *53 displayed more rigidity. SCH 66712 binding reversed flexibility in *17-2 and *17-3, through *53 remained largely rigid. Throughout simulations with docked SCH 66712, ligand orientation within the heme-binding pocket was consistent with previously identified sites of metabolism and measured binding energies. Subsequent tunnel analysis of substrate access, egress, and solvent channels displayed varied bottle-neck radii. Taken together, our results indicate that SCH 66712 should inactivate these allelic variants, although varied flexibility and substrate binding-pocket accessibility may alter its interaction abilities.

  12. Magnetic fluctuations associated with density fluctuations in the tokamak edge

    International Nuclear Information System (INIS)

    Kim, Y.J.; Gentle, K.W.; Ritz, C.P.; Rhodes, T.L.; Bengtson, R.D.

    1989-01-01

    Electrostatic density and potential fluctuations occurring with high amplitude near the edge of a tokamak are correlated with components of the fluctuating magnetic field measured outside the limiter radius. It has been established that this turbulence is associated with fluctuations in current as well as density and potential. The correlation extends for substantial toroidal distances, but only if the probes are displaced approximately along field lines, consistent with the short coherence lengths poloidally but long coherence lengths parallel to the field which are characteristic for this turbulence. Furthermore, the correlation can be found only with density fluctuations measured inside the limiter radius; density fluctuations behind the limiter have no detectable magnetic concomitant for the toroidally spaced probes used here. (author). Letter-to-the-editor. 12 refs, 3 figs

  13. Balance and flexibility.

    Science.gov (United States)

    2003-12-01

    The 'work-life balance' and flexible working are currently key buzz terms in the NHS. Those looking for more information on these topics should visit Flexibility at www.flexibility.co.uk for a host of resources designed to support new ways of working, including information on flexible workers and flexible rostering, the legal balancing act for work-life balance and home working.

  14. Polymer electronics a flexible technology

    CERN Document Server

    Technology, Rapra

    2009-01-01

    The worldwide market for polymer electronic products has been estimated to be worth up to £15 billion by 2015 and the opportunity for new markets could be as high as £125 billion by 2025.'The rapid development of polymer electronics has revealed the possibility for transforming the electronics market by offering lighter, flexible and more cost effective alternatives to conventional materials and products. With applications ranging from printed, flexible conductors and novel semiconductor components to intelligent labels and large area displays and solar panels, products that were previously un

  15. Charge Fluctuations in Nanoscale Capacitors

    NARCIS (Netherlands)

    Limmer, D.T.; Merlet, C.; Salanne, M.; Chandler, D.; Madden, P.A.; van Roij, R.H.H.G.; Rotenberg, B.

    2013-01-01

    The fluctuations of the charge on an electrode contain information on the microscopic correlations within the adjacent fluid and their effect on the electronic properties of the interface. We investigate these fluctuations using molecular dynamics simulations in a constant-potential ensemble with

  16. Fluctuating attention in Parkinson's disease

    DEFF Research Database (Denmark)

    Starrfelt, Randi; Aarsland, Dag; Janvin, Carmen

    2001-01-01

    Lewy body dementia (DLB), which share many clinical and pathological features with Parkinson’s disease (PD), is charac- terised by marked fluctuations in cognition and consciousness. Fluctuating cognition has not been formally studied in PD, although some studies indicate that PD patients show...

  17. Nonequilibrium fluctuations in a resistor.

    Science.gov (United States)

    Garnier, N; Ciliberto, S

    2005-06-01

    In small systems where relevant energies are comparable to thermal agitation, fluctuations are of the order of average values. In systems in thermodynamical equilibrium, the variance of these fluctuations can be related to the dissipation constant in the system, exploiting the fluctuation-dissipation theorem. In nonequilibrium steady systems, fluctuations theorems (FT) additionally describe symmetry properties of the probability density functions (PDFs) of the fluctuations of injected and dissipated energies. We experimentally probe a model system: an electrical dipole driven out of equilibrium by a small constant current I, and show that FT are experimentally accessible and valid. Furthermore, we stress that FT can be used to measure the dissipated power P = R I2 in the system by just studying the PDFs' symmetries.

  18. Faraday rotation echo spectroscopy and detection of quantum fluctuations.

    Science.gov (United States)

    Chen, Shao-Wen; Liu, Ren-Bao

    2014-04-15

    Central spin decoherence is useful for detecting many-body physics in environments and moreover, the spin echo control can remove the effects of static thermal fluctuations so that the quantum fluctuations are revealed. The central spin decoherence approach, however, is feasible only in some special configurations and often requires uniform coupling between the central spin and individual spins in the baths, which are very challenging in experiments. Here, by making analogue between central spin decoherence and depolarization of photons, we propose a scheme of Faraday rotation echo spectroscopy (FRES) for studying quantum fluctuations in interacting spin systems. The echo control of the photon polarization is realized by flipping the polarization with a birefringence crystal. The FRES, similar to spin echo in magnetic resonance spectroscopy, can suppress the effects of the static magnetic fluctuations and therefore reveal dynamical magnetic fluctuations. We apply the scheme to a rare-earth compound LiHoF4 and calculate the echo signal, which is related to the quantum fluctuations of the system. We observe enhanced signals at the phase boundary. The FRES should be useful for studying quantum fluctuations in a broad range of spin systems, including cold atoms, quantum dots, solid-state impurities, and transparent magnetic materials.

  19. Intermittent character of interplanetary magnetic field fluctuations

    International Nuclear Information System (INIS)

    Bruno, Roberto; Carbone, Vincenzo; Chapman, Sandra; Hnat, Bogdan; Noullez, Alain; Sorriso-Valvo, Luca

    2007-01-01

    Interplanetary magnetic field magnitude fluctuations are notoriously more intermittent than velocity fluctuations in both fast and slow wind. This behavior has been interpreted in terms of the anomalous scaling observed in passive scalars in fully developed hydrodynamic turbulence. In this paper, the strong intermittent nature of the interplanetary magnetic field is briefly discussed comparing results performed during different phases of the solar cycle. The scaling properties of the interplanetary magnetic field magnitude show solar cycle variation that can be distinguished in the scaling exponents revealed by structure functions. The scaling exponents observed around the solar maximum coincide, within the errors, to those measured for passive scalars in hydrodynamic turbulence. However, it is also found that the values are not universal in the sense that the solar cycle variation may be reflected in dependence on the structure of the velocity field

  20. Attentional fluctuations in preschoolers: Direct and indirect relations with task accuracy, academic readiness, and school performance.

    Science.gov (United States)

    Isbell, Elif; Calkins, Susan D; Swingler, Margaret M; Leerkes, Esther M

    2018-03-01

    Attentional control fluctuates in the presence of internal and external distractors, wandering on and off a given task. The current study investigated individual differences in attentional fluctuations in 250 preschoolers. Attentional fluctuations were assessed via intra-individual variability in response time in a Go/No-Go task. Greater fluctuations in attentional control were linked to lower task accuracy. In addition, greater attentional fluctuations predicted lower performance in a task of cognitive flexibility, the Dimensional Change Card Sort task. Attentional fluctuations were also associated with laboratory measures of academic readiness in preschool, as assessed by the Applied Problems and Letter-Word Identification subscales of the Woodcock-Johnson III Tests of Achievement, which in turn predicted teacher reports of academic performance in first grade. Attentional fluctuations also had indirect associations with emergent math skills in preschool, via cognitive flexibility, as well as indirect associations with first-grade teacher reports of academic performance, via the relations between cognitive flexibility and emergent math skills in preschool. These results suggest that consistency is an important aspect of attentional control during early childhood. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Quantum fluctuations from thermal fluctuations in Jacobson formalism

    Energy Technology Data Exchange (ETDEWEB)

    Faizal, Mir [University of British Columbia-Okanagan, Irving K. Barber School of Arts and Sciences, Kelowna, BC (Canada); University of Lethbridge, Department of Physics and Astronomy, Lethbridge, AB (Canada); Ashour, Amani; Alcheikh, Mohammad [Damascus University, Mathematics Department, Faculty of Science, Damascus (Syrian Arab Republic); Alasfar, Lina [Universite Clermont Auvergne, Laboratoire de Physique Corpusculaire de Clermont-Ferrand, Aubiere (France); Alsaleh, Salwa; Mahroussah, Ahmed [King Saud University, Department of Physics and Astronomy, Riyadh (Saudi Arabia)

    2017-09-15

    In the Jacobson formalism general relativity is obtained from thermodynamics. This is done by using the Bekenstein-Hawking entropy-area relation. However, as a black hole gets smaller, its temperature will increase. This will cause the thermal fluctuations to also increase, and these will in turn correct the Bekenstein-Hawking entropy-area relation. Furthermore, with the reduction in the size of the black hole, quantum effects will also start to dominate. Just as the general relativity can be obtained from thermodynamics in the Jacobson formalism, we propose that the quantum fluctuations to the geometry can be obtained from thermal fluctuations. (orig.)

  2. 5th International Conference on Valence Fluctuations

    CERN Document Server

    Malik, S

    1987-01-01

    During the Koln meeting (August 28-31, 1984), Irdia was chosen as the venue for the next International Conference on Valence Fluctuations. lhis was in recognition ard appreciation of the work done, both experimental ard theoretical, by the Irdian scientists in this area during the last decade. We decided to hold this Conference in the month of January, 1987 at Bangalore. lhe subject of Valence Fluctuations has kept itself alive ard active as it has provided many shocks ard suprises particularly among the Ce- ard U-based intermetallies. lhe richness of many interesting physical phenomena occurring in mixed valent materials, the flexibility of modifying their physical properties (by alloying, for example) ard the possibility of synthesizing a wide variety of new such materials seem to be the key factors in this regard. Barely six months before this Conference, an International Conference on Anomalous Rare Earths and Actinides (ICAREA) had been held at Grenoble (July, 1986) which also focussed on mixed valence a...

  3. Pressure-induced americium valence fluctuations revealed by electrical resistivity

    Czech Academy of Sciences Publication Activity Database

    Kolomiets, A. V.; Griveau, J.C.; Heathman, S.; Shick, Alexander; Wastin, F.; Faure, P.; Klosek, V.; Genestier, C.; Baclet, N.; Havela, L.

    2008-01-01

    Roč. 82, č. 5 (2008), 57007/1-57007/5 ISSN 0295-5075 R&D Projects: GA MŠk OC 144; GA ČR GA202/07/0644 Grant - others:EU(XE) RITA -CT-2006-026176 Institutional research plan: CEZ:AV0Z10100520 Keywords : electrical conductivity * strong electron interactions * electronic structure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.203, year: 2008

  4. Demand flexibility from residential heat pump

    DEFF Research Database (Denmark)

    Bhattarai, Bishnu Prasad; Bak-Jensen, Birgitte; Pillai, Jayakrishnan Radhakrishna

    2014-01-01

    Demand response (DR) is considered as a potentially effective tool to compensate generation intermittency imposed by renewable sources. Further, DR can instigate to offer optimum asset utilization and to avoid or delay the need for new infrastructure investment. Being a sizable load together...... with high thermal time constant, heat pumps (HP) can offer a great deal of flexibility in the future intelligent grids especially to compensate fluctuating generation. However, the HP flexibility is highly dependent on thermal demand profile, namely hot water and space heating demand. This paper proposes...... price based scheduling followed by a demand dispatch based central control and a local voltage based adaptive control, to realize HP demand flexibility. Two-step control architecture, namely local primary control encompassed by the central coordinative control, is proposed to implement...

  5. Current density fluctuations and ambipolarity of transport

    International Nuclear Information System (INIS)

    Shen, W.; Dexter, R.N.; Prager, S.C.

    1991-10-01

    The fluctuation in the plasma current density is measured in the MIST reversed field pinch experiment. Such fluctuations, and the measured radial profile of the k spectrum of magnetic fluctuations, supports the view and that low frequency fluctuations (f r >) demonstrates that radial particle transport from particle motion parallel to a fluctuating magnetic field is ambipolar over the full frequency range

  6. Flexible magnetoimpedance sensor

    KAUST Repository

    Li, Bodong; Kavaldzhiev, Mincho; Kosel, Jü rgen

    2015-01-01

    Flexible magnetoimpedance (MI) sensors fabricated using a NiFe/Cu/NiFe tri-layer on Kapton substrate have been studied. A customized flexible microstrip transmission line was employed to investigate the MI sensors's magnetic field and frequency

  7. Nonlinear correlations in the hydrophobicity and average flexibility along the glycolytic enzymes sequences

    International Nuclear Information System (INIS)

    Ciorsac, Alecu; Craciun, Dana; Ostafe, Vasile; Isvoran, Adriana

    2011-01-01

    Research highlights: → We focus our study on the glycolytic enzymes. → We reveal correlation of hydrophobicity and flexibility along their chains. → We also reveal fractal aspects of the glycolytic enzymes structures and surfaces. → The glycolytic enzyme sequences are not random. → Creation of fractal structures requires the operation of nonlinear dynamics. - Abstract: Nonlinear methods widely used for time series analysis were applied to glycolytic enzyme sequences to derive information concerning the correlation of hydrophobicity and average flexibility along their chains. The 20 sequences of different types of the 10 human glycolytic enzymes were considered as spatial series and were analyzed by spectral analysis, detrended fluctuations analysis and Hurst coefficient calculation. The results agreed that there are both short range and long range correlations of hydrophobicity and average flexibility within investigated sequences, the short range correlations being stronger and indicating that local interactions are the most important for the protein folding. This correlation is also reflected by the fractal nature of the structures of investigated proteins.

  8. Nonlinear correlations in the hydrophobicity and average flexibility along the glycolytic enzymes sequences

    Energy Technology Data Exchange (ETDEWEB)

    Ciorsac, Alecu, E-mail: aleciorsac@yahoo.co [Politehnica University of Timisoara, Department of Physical Education and Sport, 2 P-ta Victoriei, 300006, Timisoara (Romania); Craciun, Dana, E-mail: craciundana@gmail.co [Teacher Training Department, West University of Timisoara, 4 Boulevard V. Pirvan, Timisoara, 300223 (Romania); Ostafe, Vasile, E-mail: vostafe@cbg.uvt.r [Department of Chemistry, West University of Timisoara, 16 Pestallozi, 300115, Timisoara (Romania); Laboratory of Advanced Researches in Environmental Protection, Nicholas Georgescu-Roegen Interdisciplinary Research and Formation Platform, 4 Oituz, Timisoara, 300086 (Romania); Isvoran, Adriana, E-mail: aisvoran@cbg.uvt.r [Department of Chemistry, West University of Timisoara, 16 Pestallozi, 300115, Timisoara (Romania); Laboratory of Advanced Researches in Environmental Protection, Nicholas Georgescu-Roegen Interdisciplinary Research and Formation Platform, 4 Oituz, Timisoara, 300086 (Romania)

    2011-04-15

    Research highlights: lights: We focus our study on the glycolytic enzymes. We reveal correlation of hydrophobicity and flexibility along their chains. We also reveal fractal aspects of the glycolytic enzymes structures and surfaces. The glycolytic enzyme sequences are not random. Creation of fractal structures requires the operation of nonlinear dynamics. - Abstract: Nonlinear methods widely used for time series analysis were applied to glycolytic enzyme sequences to derive information concerning the correlation of hydrophobicity and average flexibility along their chains. The 20 sequences of different types of the 10 human glycolytic enzymes were considered as spatial series and were analyzed by spectral analysis, detrended fluctuations analysis and Hurst coefficient calculation. The results agreed that there are both short range and long range correlations of hydrophobicity and average flexibility within investigated sequences, the short range correlations being stronger and indicating that local interactions are the most important for the protein folding. This correlation is also reflected by the fractal nature of the structures of investigated proteins.

  9. Constructing a folding model for protein S6 guided by native fluctuations deduced from NMR structures

    International Nuclear Information System (INIS)

    Lammert, Heiko; Noel, Jeffrey K.; Haglund, Ellinor; Onuchic, José N.; Schug, Alexander

    2015-01-01

    The diversity in a set of protein nuclear magnetic resonance (NMR) structures provides an estimate of native state fluctuations that can be used to refine and enrich structure-based protein models (SBMs). Dynamics are an essential part of a protein’s functional native state. The dynamics in the native state are controlled by the same funneled energy landscape that guides the entire folding process. SBMs apply the principle of minimal frustration, drawn from energy landscape theory, to construct a funneled folding landscape for a given protein using only information from the native structure. On an energy landscape smoothed by evolution towards minimal frustration, geometrical constraints, imposed by the native structure, control the folding mechanism and shape the native dynamics revealed by the model. Native-state fluctuations can alternatively be estimated directly from the diversity in the set of NMR structures for a protein. Based on this information, we identify a highly flexible loop in the ribosomal protein S6 and modify the contact map in a SBM to accommodate the inferred dynamics. By taking into account the probable native state dynamics, the experimental transition state is recovered in the model, and the correct order of folding events is restored. Our study highlights how the shared energy landscape connects folding and function by showing that a better description of the native basin improves the prediction of the folding mechanism

  10. Mind-Body Practice Changes Fractional Amplitude of Low Frequency Fluctuations in Intrinsic Control Networks

    Directory of Open Access Journals (Sweden)

    Gao-Xia Wei

    2017-07-01

    Full Text Available Cognitive control impairment is a typical symptom largely reported in populations with neurological disorders. Previous studies have provided evidence about the changes in cognitive control induced by mind-body training. However, the neural correlates underlying the effect of extensive mind-body practice on cognitive control remain largely unknown. Using resting-state functional magnetic resonance imaging, we characterized dynamic fluctuations in large-scale intrinsic connectivity networks associated with mind-body practice, and examined their differences between healthy controls and Tai Chi Chuan (TCC practitioners. Compared with a control group, the TCC group revealed significantly decreased fractional Amplitude of Low Frequency Fluctuations (fALFF in the bilateral frontoparietal network, default mode network and dorsal prefrontal-angular gyri network. Furthermore, we detected a significant association between mind-body practice experience and fALFF in the default mode network, as well as an association between cognitive control performance and fALFF of the frontoparietal network. This provides the first evidence of large-scale functional connectivity in brain networks associated with mind-body practice, shedding light on the neural network changes that accompany intensive mind-body training. It also highlights the functionally plastic role of the frontoparietal network in the context of the “immune system” of mental health recently developed in relation to flexible hub theory.

  11. Mind-Body Practice Changes Fractional Amplitude of Low Frequency Fluctuations in Intrinsic Control Networks.

    Science.gov (United States)

    Wei, Gao-Xia; Gong, Zhu-Qing; Yang, Zhi; Zuo, Xi-Nian

    2017-01-01

    Cognitive control impairment is a typical symptom largely reported in populations with neurological disorders. Previous studies have provided evidence about the changes in cognitive control induced by mind-body training. However, the neural correlates underlying the effect of extensive mind-body practice on cognitive control remain largely unknown. Using resting-state functional magnetic resonance imaging, we characterized dynamic fluctuations in large-scale intrinsic connectivity networks associated with mind-body practice, and examined their differences between healthy controls and Tai Chi Chuan (TCC) practitioners. Compared with a control group, the TCC group revealed significantly decreased fractional Amplitude of Low Frequency Fluctuations (fALFF) in the bilateral frontoparietal network, default mode network and dorsal prefrontal-angular gyri network. Furthermore, we detected a significant association between mind-body practice experience and fALFF in the default mode network, as well as an association between cognitive control performance and fALFF of the frontoparietal network. This provides the first evidence of large-scale functional connectivity in brain networks associated with mind-body practice, shedding light on the neural network changes that accompany intensive mind-body training. It also highlights the functionally plastic role of the frontoparietal network in the context of the "immune system" of mental health recently developed in relation to flexible hub theory.

  12. Flexible Carpooling: Exploratory Study

    OpenAIRE

    Dorinson, Diana; Gay, Deanna; Minett, Paul; Shaheen, Susan

    2009-01-01

    Energy consumption could be reduced if more people shared rides rather than driving alone yet carpooling represents a small proportion of all potential carpoolers. Prior research has found that many who might carpool were concerned about reduced flexibility with carpooling. If flexibility is one of the barriers how could carpooling be organized to be more flexible? In Northern Virginia a flexible system has evolved where there are 3,500 single-use carpools per day. In another example there ...

  13. Localized description of valence fluctuations

    International Nuclear Information System (INIS)

    Alascio, B.; Allub, R.; Aligia, A.

    1979-07-01

    The authors set up a model for intermediate valence equivalent to the ''atomic'' limit of the Anderson Hamiltonian. Detailed analysis of this model shows that most of the essential characteristics of valence fluctuators are already present in this crudely simplified Hamiltonian. The spin-spin and the 4f charge-charge correlation functions are studied and it is shown that it is possible to define a spin fluctuation frequency ωsub(s.f.) and a charge fluctuation frequency ωsub(ch.f.).ωsub(s.f.) and ωsub(ch.f.) can differ considerably for some values of the parameters of the model. The magnetic susceptibility and the specific heat are calculated as functions of temperature and it is shown how the results simulate the behaviour found in valence fluctuators. (author)

  14. The Fluctuation Niche in Plants

    Directory of Open Access Journals (Sweden)

    Jaume Terradas

    2009-01-01

    Full Text Available Classical approaches to niche in coexisting plants have undervalued temporal fluctuations. We propose that fluctuation niche is an important dimension of the total niche and interacts with habitat and life-history niches to provide a better understanding of the multidimensional niche space where ecological interactions occur. To scale a fluctuation niche, it is necessary to relate environmental constrictions or species performance not only to the absolute values of the usual environmental and ecophysiological variables but also to their variances or other measures of variability. We use Mediterranean plant communities as examples, because they present characteristic large seasonal and interannual fluctuations in water and nutrient availabilities, along an episodic-constant gradient, and because the plant responses include a number of syndromes coupled to this gradient.

  15. The Fluctuation Niche in Plants

    International Nuclear Information System (INIS)

    Terradas, J.; Penuelas, J.; Lloret, F.; Penuelas, J.

    2009-01-01

    Classical approaches to niche in coexisting plants have undervalued temporal fluctuations. We propose that fluctuation niche is an important dimension of the total niche and interacts with habitat and life-history niches to provide a better understanding of the multidimensional niche space where ecological interactions occur. To scale a fluctuation niche, it is necessary to relate environmental constrictions or species performance not only to the absolute values of the usual environmental and eco physiological variables but also to their variances or other measures of variability. We use Mediterranean plant communities as examples, because they present characteristic large seasonal and inter annual fluctuations in water and nutrient availabilities, along an episodic-constant gradient, and because the plant responses include a number of syndromes coupled to this gradient.

  16. Insects in fluctuating thermal environments.

    Science.gov (United States)

    Colinet, Hervé; Sinclair, Brent J; Vernon, Philippe; Renault, David

    2015-01-07

    All climate change scenarios predict an increase in both global temperature means and the magnitude of seasonal and diel temperature variation. The nonlinear relationship between temperature and biological processes means that fluctuating temperatures lead to physiological, life history, and ecological consequences for ectothermic insects that diverge from those predicted from constant temperatures. Fluctuating temperatures that remain within permissive temperature ranges generally improve performance. By contrast, those which extend to stressful temperatures may have either positive impacts, allowing repair of damage accrued during exposure to thermal extremes, or negative impacts from cumulative damage during successive exposures. We discuss the mechanisms underlying these differing effects. Fluctuating temperatures could be used to enhance or weaken insects in applied rearing programs, and any prediction of insect performance in the field-including models of climate change or population performance-must account for the effect of fluctuating temperatures.

  17. Nonequilibrium quantum fluctuations of work.

    Science.gov (United States)

    Allahverdyan, A E

    2014-09-01

    The concept of work is basic for statistical thermodynamics. To gain a fuller understanding of work and its (quantum) features, it needs to be represented as an average of a fluctuating quantity. Here I focus on the work done between two moments of time for a thermally isolated quantum system driven by a time-dependent Hamiltonian. I formulate two natural conditions needed for the fluctuating work to be physically meaningful for a system that starts its evolution from a nonequilibrium state. The existing definitions do not satisfy these conditions due to issues that are traced back to noncommutativity. I propose a definition of fluctuating work that is free of previous drawbacks and that applies for a wide class of nonequilibrium initial states. It allows the deduction of a generalized work-fluctuation theorem that applies for an arbitrary (out-of-equilibrium) initial state.

  18. Quantum fluctuations in insulating ferroelectrics

    International Nuclear Information System (INIS)

    Riseborough, Peter S.

    2010-01-01

    Graphical abstract: It has been proposed that in a ferroelectric insulator, an applied magnetic field may couple the transverse phonon modes and produce left and right circularly polarized phonon modes which are no longer degenerate. We quantize the theory and examine the effects of quantal fluctuations. In particular, we show that the zero point fluctuations result in a large diamagnetic contribution to the magnetic susceptibility. - Abstract: It has been proposed that in a ferroelectric insulator, an applied magnetic field may couple the transverse phonon modes and produce left and right circularly polarized phonon modes which are no longer degenerate. We quantize the theory and examine the effects of quantal fluctuations. In particular, we show that the zero-point fluctuations result in a large diamagnetic contribution to the magnetic susceptibility.

  19. Fluctuations and Instability in Sedimentation

    KAUST Repository

    Guazzelli, Élisabeth

    2011-01-21

    This review concentrates on the fluctuations of the velocities of sedimenting spheres, and on the structural instability of a suspension of settling fibers. For many years, theoretical estimates and numerical simulations predicted the fluctuations of the velocities of spheres to increase with the size of the container, whereas experiments found no such variation. Two ideas have increased our understanding. First, the correlation length of the velocity fluctuations was found experimentally to be 20 interparticle separations. Second, in dilute suspensions, a vertical variation in the concentration due to the spreading of the front with the clear fluid can inhibit the velocity fluctuations. In a very dilute regime, a homogeneous suspension of fibers suffers a spontaneous instability in which fast descending fiber-rich columns are separated by rising fiber-sparse columns. In a semidilute regime, the settling is hindered, more so than for spheres. © 2011 by Annual Reviews. All rights reserved.

  20. Principle of minimal work fluctuations.

    Science.gov (United States)

    Xiao, Gaoyang; Gong, Jiangbin

    2015-08-01

    Understanding and manipulating work fluctuations in microscale and nanoscale systems are of both fundamental and practical interest. For example, in considering the Jarzynski equality 〈e-βW〉=e-βΔF, a change in the fluctuations of e-βW may impact how rapidly the statistical average of e-βW converges towards the theoretical value e-βΔF, where W is the work, β is the inverse temperature, and ΔF is the free energy difference between two equilibrium states. Motivated by our previous study aiming at the suppression of work fluctuations, here we obtain a principle of minimal work fluctuations. In brief, adiabatic processes as treated in quantum and classical adiabatic theorems yield the minimal fluctuations in e-βW. In the quantum domain, if a system initially prepared at thermal equilibrium is subjected to a work protocol but isolated from a bath during the time evolution, then a quantum adiabatic process without energy level crossing (or an assisted adiabatic process reaching the same final states as in a conventional adiabatic process) yields the minimal fluctuations in e-βW, where W is the quantum work defined by two energy measurements at the beginning and at the end of the process. In the classical domain where the classical work protocol is realizable by an adiabatic process, then the classical adiabatic process also yields the minimal fluctuations in e-βW. Numerical experiments based on a Landau-Zener process confirm our theory in the quantum domain, and our theory in the classical domain explains our previous numerical findings regarding the suppression of classical work fluctuations [G. Y. Xiao and J. B. Gong, Phys. Rev. E 90, 052132 (2014)].

  1. Fluctuation-Driven Neural Dynamics Reproduce Drosophila Locomotor Patterns.

    Directory of Open Access Journals (Sweden)

    Andrea Maesani

    2015-11-01

    Full Text Available The neural mechanisms determining the timing of even simple actions, such as when to walk or rest, are largely mysterious. One intriguing, but untested, hypothesis posits a role for ongoing activity fluctuations in neurons of central action selection circuits that drive animal behavior from moment to moment. To examine how fluctuating activity can contribute to action timing, we paired high-resolution measurements of freely walking Drosophila melanogaster with data-driven neural network modeling and dynamical systems analysis. We generated fluctuation-driven network models whose outputs-locomotor bouts-matched those measured from sensory-deprived Drosophila. From these models, we identified those that could also reproduce a second, unrelated dataset: the complex time-course of odor-evoked walking for genetically diverse Drosophila strains. Dynamical models that best reproduced both Drosophila basal and odor-evoked locomotor patterns exhibited specific characteristics. First, ongoing fluctuations were required. In a stochastic resonance-like manner, these fluctuations allowed neural activity to escape stable equilibria and to exceed a threshold for locomotion. Second, odor-induced shifts of equilibria in these models caused a depression in locomotor frequency following olfactory stimulation. Our models predict that activity fluctuations in action selection circuits cause behavioral output to more closely match sensory drive and may therefore enhance navigation in complex sensory environments. Together these data reveal how simple neural dynamics, when coupled with activity fluctuations, can give rise to complex patterns of animal behavior.

  2. Spatial mobility fluctuation induced giant linear magnetoresistance in multilayered graphene foam

    KAUST Repository

    Li, Peng

    2016-07-05

    Giant, positive, and near-temperature-independent linear magnetoresistance (LMR), as large as 340%, was observed in graphene foam with a three-dimensional flexible network. Careful analysis of the magnetoresistance revealed that Shubnikov–de Haas (SdH) oscillations occurred at low temperatures and decayed with increasing temperature. The average classical mobility ranged from 300 (2 K) to 150 (300 K) cm2V−1s−1, which is much smaller than that required by the observed SdH oscillations. To understand the mechanism behind the observation, we performed the same measurements on the microsized graphene sheets that constitute the graphene foam. Much more pronounced SdH oscillations superimposed on the LMR background were observed in these microscaled samples, which correspond to a quantum mobility as high as 26,500cm2V−1s−1. Moreover, the spatial mobility fluctuated significantly from 64,200cm2V−1s−1 to 1370cm2V−1s−1, accompanied by a variation of magnetoresistance from near 20,000% to less than 20%. The presence of SdH oscillations actually excludes the possibility that the observed LMR originated from the extreme quantum limit, because this would demand all electrons to be in the first Landau level. Instead, we ascribe the large LMR to the second case of the classical Parish and Littlewood model, in which spatial mobility fluctuation dominates electrical transport. This is an experimental confirmation of the Parish and Littlewood model by measuring the local mobility randomly (by measuring the microsized graphene sheets) and finding the spatial mobility fluctuation.

  3. Fluctuation analysis of rotational spectra

    International Nuclear Information System (INIS)

    Doessing, T.; Bracco, A.; Broglia, R.A.; Matsuo, M.

    1996-01-01

    The compound state rotational degree of freedom is ''damped'' in the sense that the electric quadrupole decay of a single quantum state with angular momentum I exhibits a spectrum of final states all having spin I-2. In actual experiments, the cascade of γ-rays associated with each of the members of the ensemble of compound nuclei uses each of the ''discrete'' transitions many more times than the ''continuum'' transitions. Relatively large and small fluctuations in the recorded coincidence spectrum ensue, respectively. The analysis of the fluctuations will be shown to be instrumental to gain insight into the phenomenon of rotational damping. For this purpose, two- and higher-fold coincidence spectra emitted from rotating nuclei are analyzed with respect to the count fluctuations. The coincidences from consecutive γ-rays emitted from discrete rotational bands generate ridges in the E γ1 .E γ2 spectrum, and the fluctuation analysis of the ridges is based upon the ansatz of a random selection of transition energies from band to band. This ansatz is supported by a cranked mean-field calculation for the nucleus 168 Yb, as well as by analyzing resolved bands in 168 Yb and its neighbors. The fluctuation analysis of the central valley (E γ1 =E γ2 ) is based upon the ansatz of fluctuations in the intensity of the transitions of Porter-Thomas type superposed on a smooth spectrum of transition energies. This ansatz is again supported by a mixed-band calculation. The mathematical treatment of count fluctuations is formulated in general (orig.)

  4. Production Flexibility in Extensive Beef Farming Systems

    Directory of Open Access Journals (Sweden)

    Laura Astigarraga

    2011-03-01

    Full Text Available The aim of this work is to assess the flexibility of production allowed by extensive production conditions faced with variations in the environment, i.e., market variations and climatic fluctuations, of Limousin beef systems. The study used a case-based methodology in which seven beef farms with less than 1 LU/ha were chosen. Data collection was based on three interviews using a semistructured questionnaire and on the analysis of productive and economic results over a 15-year period (1991-2005. The main evolution of these farms is related to a rise in work productivity associated with an increase in herd size. Herd increase was made possible by enlarging the area, the margin of intensification being limited in these regions. To take advantage of the enlarged land area, females were reared for fattening or for reproduction instead of selling them at weaning. The Limousin female provides a wide product mix because of its plasticity, as has been studied by several researchers. This mix flexibility is achieved by delaying product differentiation, a form of production flexibility that can reduce the risk of under-producing or over-producing varied product configurations. On the other hand, calves sold to the Italian market after weaning are generic products, associated with a flexible production process to overcome fluctuations in forage availability due to climatic variations. The introduction of maize silage for feeding acts as an alternative route, actual and potential, through the system to overcome unexpected forage shortage from natural grasslands as a result of droughts. The study shows that extensive farming systems have developed types of flexibility to match different factors of uncertainty from the environment. Finally, the issue of farm system performance is thus not so much a question of whether a farm is fit at a specific moment in time, but whether it transforms into a less or more sustainable orientation.

  5. Topics in fluctuating nonlinear hydrodynamics

    International Nuclear Information System (INIS)

    Milner, S.T.

    1986-01-01

    Models of fluctuating nonlinear hydrodynamics have enjoyed much success in explaining the effect of long-wavelength fluctuations in diverse hydrodynamic systems. This thesis explores two such problems; in both, the body of hydrodynamic assumptions powerfully constrains the predictions of a well-posed theory. The effects of layer fluctuations in smectic-A liquid crystals are first examined. The static theory (introduced by Grinstein and Pelcovits) is reviewed. Ward identities, resulting from the arbitrariness of the layering direction, are derived and exploited. The static results motivate an examination of dynamic fluctuation effects. A new sound-damping experiment is proposed that would probe singular dependence of viscosities on applied stress. A theory of Procaccia and Gitterman that reaction rates of chemically reacting binary mixtures are drastically reduced near their thermodynamic critical points is analyzed. Hydrodynamic arguments and Van Hove theory are applied, concluding that the PG idea is drastically slowed, and spatially varying composition fluctuations are at best slowed down over a narrow range of wavenumbers

  6. Electric Field Fluctuations in Water

    Science.gov (United States)

    Thorpe, Dayton; Limmer, David; Chandler, David

    2013-03-01

    Charge transfer in solution, such as autoionization and ion pair dissociation in water, is governed by rare electric field fluctuations of the solvent. Knowing the statistics of such fluctuations can help explain the dynamics of these rare events. Trajectories short enough to be tractable by computer simulation are virtually certain not to sample the large fluctuations that promote rare events. Here, we employ importance sampling techniques with classical molecular dynamics simulations of liquid water to study statistics of electric field fluctuations far from their means. We find that the distributions of electric fields located on individual water molecules are not in general gaussian. Near the mean this non-gaussianity is due to the internal charge distribution of the water molecule. Further from the mean, however, there is a previously unreported Bjerrum-like defect that stabilizes certain large fluctuations out of equilibrium. As expected, differences in electric fields acting between molecules are gaussian to a remarkable degree. By studying these differences, though, we are able to determine what configurations result not only in large electric fields, but also in electric fields with long spatial correlations that may be needed to promote charge separation.

  7. Multiscale fluctuations in nuclear response

    International Nuclear Information System (INIS)

    Lacroix, D.; Chomaz, Ph.

    1999-01-01

    The nuclear collective response is investigated in the framework of a doorway picture in which the spreading width of the collective emotion is described as a coupling to more and more complex configurations. It is shown that this coupling induces fluctuations of the observed strength. In the case of a hierarchy of overlapping decay channels, Ericson fluctuations are observed at different scales. Methods for extracting these scales and the related lifetimes are discussed. Finally, it is shown that the coupling of different states at one level of complexity to some common decay channels at the next level, may produce interference-like patterns in the nuclear response. This quantum effect leads to anew type of fluctuations with a typical width related to the level spacing. (author)

  8. Fluctuation relations for anomalous dynamics

    International Nuclear Information System (INIS)

    Chechkin, A V; Klages, R

    2009-01-01

    We consider work fluctuation relations (FRs) for generic types of dynamics generating anomalous diffusion: Lévy flights, long-correlated Gaussian processes and time-fractional kinetics. By combining Langevin and kinetic approaches we calculate the probability distributions of mechanical and thermodynamical work in two paradigmatic nonequilibrium situations, respectively: a particle subject to a constant force and a particle in a harmonic potential dragged by a constant force. We check the transient FR for two models exhibiting superdiffusion, where a fluctuation-dissipation relation does not exist, and for two other models displaying subdiffusion, where there is a fluctuation-dissipation relation. In the two former cases the conventional transient FR is not recovered, whereas in the latter two it holds either exactly or in the long-time limit. (letter)

  9. Fluctuations in the multiparticle dynamics

    International Nuclear Information System (INIS)

    Bozek, P.; Ploszajczak, M.

    1993-01-01

    The appearance and properties of intermittent fluctuations in physical systems, in particular the formation of rare structures in transport phenomena are discussed. The distribution of fluctuations approaches a limiting log-normal statistical distribution. The log-normal distribution is introduced as a simple parametrization of the energy fluctuations leading to the subthreshold production of particles in nuclear collisions, and it is shown that it fits all available data both for total π 0 production cross section as well as the π 0 kinetic energy spectra for E/A < 90 MeV. It is suggested that the same universal distribution should also describe the subthreshold production of other hadrons like η and K. (author) 36 refs., 11 figs

  10. Multiscale fluctuations in nuclear response

    Energy Technology Data Exchange (ETDEWEB)

    Lacroix, D.; Chomaz, Ph

    1999-01-01

    The nuclear collective response is investigated in the framework of a doorway picture in which the spreading width of the collective emotion is described as a coupling to more and more complex configurations. It is shown that this coupling induces fluctuations of the observed strength. In the case of a hierarchy of overlapping decay channels, Ericson fluctuations are observed at different scales. Methods for extracting these scales and the related lifetimes are discussed. Finally, it is shown that the coupling of different states at one level of complexity to some common decay channels at the next level, may produce interference-like patterns in the nuclear response. This quantum effect leads to anew type of fluctuations with a typical width related to the level spacing. (author) 25 refs.

  11. A Clearinghouse Concept for Distribution-Level Flexibility Services

    DEFF Research Database (Denmark)

    Heussen, Kai; Bondy, Daniel Esteban Morales; Hu, Junjie

    2013-01-01

    Flexibility resources on the demand side are anticipated to become a valuable asset for balancing renewable energy fluctuation as well as for reducing investment needs in distribution grids. To harvest this flexibility for distribution grids, flexibility services need to be defined that can...... be integrated with distribution grid operation and that provide a benefit that can be traded off against other grid investments. Two key challenges are here that the identification of useful services is still ongoing and that the transaction cost for the individually small contributions from the demand side...... could be prohibitive. This paper introduces a flexibility clearinghouse (FLECH) concept and isolates FLECH key functionality: to facilitate flexibility services in distribution grids by streamlining the relevant business interactions while keeping technical specifications open....

  12. Phase space fluctuations and dynamics of fluctuations of collective variables

    Energy Technology Data Exchange (ETDEWEB)

    Benhassine, B.; Farine, M.; Idier, D.; Remaud, B.; Sebille, F. (Lab. de Physique Nucleaire, IN2P3/CNRS, 44 - Nantes (France) Nantes Univ., 44 (France)); Hernandez, E.S. (Dept. de Fisica, Ciudad Universitaria, Buenos Aires (Argentina))

    1992-08-03

    Within the framework of theoretical approaches based on stochastic transport equation of one-body distribution function, a numerical treatment of the fluctuations of collective observables is studied and checked in comparison with analytical results either at equilibrium or close to it. (orig.).

  13. Phase space fluctuations and dynamics of fluctuations of collective variables

    International Nuclear Information System (INIS)

    Benhassine, B.; Farine, M.; Idier, D.; Remaud, B.; Sebille, F.; Hernandez, E.S.

    1992-01-01

    Within the framework of theoretical approaches based on stochastic transport equation of one-body distribution function, a numerical treatment of the fluctuations of collective observables is studied and checked in comparison with analytical results either at equilibrium or close to it. (orig.)

  14. Entropic Repulsion Between Fluctuating Surfaces

    Science.gov (United States)

    Janke, W.

    The statistical mechanics of fluctuating surfaces plays an important role in a variety of physical systems, ranging from biological membranes to world sheets of strings in theories of fundamental interactions. In many applications it is a good approximation to assume that the surfaces possess no tension. Their statistical properties are then governed by curvature energies only, which allow for gigantic out-of-plane undulations. These fluctuations are the “entropic” origin of long-range repulsive forces in layered surface systems. Theoretical estimates of these forces for simple model surfaces are surveyed and compared with recent Monte Carlo simulations.

  15. Origin of cosmological density fluctuations

    International Nuclear Information System (INIS)

    Carr, B.J.

    1984-11-01

    The density fluctuations required to explain the large-scale cosmological structure may have arisen spontaneously as a result of a phase transition in the early Universe. There are several ways in which such fluctuations may have ben produced, and they could have a variety of spectra, so one should not necessarily expect all features of the large-scale structure to derive from a simple power law spectrum. Some features may even result from astrophysical amplification mechanisms rather than gravitational instability. 128 references

  16. A methodology for designing flexible multi-generation systems

    DEFF Research Database (Denmark)

    Lythcke-Jørgensen, Christoffer Ernst; Viana Ensinas, Adriano; Münster, Marie

    2016-01-01

    An FMG (flexible multi-generation system) consists of integrated and flexibly operated facilities that provide multiple links between the various layers of the energy system. FMGs may facilitate integration and balancing of fluctuating renewable energy sources in the energy system in a cost...... is based on consideration of the following points: Selection, location and dimensioning of processes; systematic heat and mass integration; flexible operation optimization with respect to both short-term market fluctuations and long-term energy system development; global sensitivity and uncertainty...... analysis; biomass supply chains; variable part-load performance; and multi-objective optimization considering economic and environmental performance. Tested in a case study, the methodology is proved effective in screening the solution space for efficient FMG designs, in assessing the importance...

  17. Office flexible cystoscopy.

    Science.gov (United States)

    Kavoussi, L R; Clayman, R V

    1988-11-01

    Since the development of the first purpose-built flexible cystoscope in 1984, flexible cystoscopy has become an accepted diagnostic and therapeutic modality. Indeed, it is estimated that more than 10 per cent of practicing urologists are already familiar with this technology. The flexible cystoscope has markedly extended the urologist's ability to examine the bladder, and it has become a valuable adjunct to the rigid cystoscope. Although the operation of this instrument is vastly different from that of its rigid counterpart, with practice, the technique can be learned. After experience is obtained with diagnostic flexible cystoscopy, the urologist will likely prefer this new instrument for bladder inspection, as it provides for a more thorough yet less morbid and less expensive examination. In the future, the development of improved and smaller instrumentation will further extend the therapeutic indications for flexible cystoscopy. Indeed, advances in laser technology are already providing the urologist with 300- to 600-micron (0.9 to 1.8F) flexible probes capable of incision (KTP laser), fulguration (Nd:YAG laser), and stone disintegration (tunable dye laser). Lastly, the skills obtained in using the flexible cystoscope are all readily applicable to the development of dexterity with the already available flexible nephroscope and the more recently developed flexible ureteroscope.

  18. On the origin of shape fluctuations of the cell nucleus.

    Science.gov (United States)

    Chu, Fang-Yi; Haley, Shannon C; Zidovska, Alexandra

    2017-09-26

    The nuclear envelope (NE) presents a physical boundary between the cytoplasm and the nucleoplasm, sandwiched in between two highly active systems inside the cell: cytoskeleton and chromatin. NE defines the shape and size of the cell nucleus, which increases during the cell cycle, accommodating for chromosome decondensation followed by genome duplication. In this work, we study nuclear shape fluctuations at short time scales of seconds in human cells. Using spinning disk confocal microscopy, we observe fast fluctuations of the NE, visualized by fluorescently labeled lamin A, and of the chromatin globule surface (CGS) underneath the NE, visualized by fluorescently labeled histone H2B. Our findings reveal that fluctuation amplitudes of both CGS and NE monotonously decrease during the cell cycle, serving as a reliable cell cycle stage indicator. Remarkably, we find that, while CGS and NE typically fluctuate in phase, they do exhibit localized regions of out-of-phase motion, which lead to separation of NE and CGS. To explore the mechanism behind these shape fluctuations, we use biochemical perturbations. We find the shape fluctuations of CGS and NE to be both thermally and actively driven, the latter caused by forces from chromatin and cytoskeleton. Such undulations might affect gene regulation as well as contribute to the anomalously high rates of nuclear transport by, e.g., stirring of molecules next to NE, or increasing flux of molecules through the nuclear pores.

  19. Fluctuations in Overlapping Generations Economies

    DEFF Research Database (Denmark)

    Tvede, Mich

    . The approach to existence of endogenous fluctuations is basic in the sense that the prime ingredients are the implicit function theorem and linear algebra. Moreover the approach is applied to show that for an open and dense set of utility functions there exist endowment vectors such that sunspot equilibria...

  20. Magnetic fluctuations in turbulent flow

    International Nuclear Information System (INIS)

    Ruzmaikin, A.A.

    1990-01-01

    For dynamo excitation of the magnetic fluctuations in infinite fluid only a sufficient large magnetic Reynolds number is needed. In a infinite region an additional condition appears. Due to the diffusion of the magnetic field through the boundaries a size of the region must be large enough compare with a correlation length of the turbulence. Author)

  1. Firm default and aggregate fluctuations

    NARCIS (Netherlands)

    Jacobson, Tor; Linde, Jesper; Roszbach, Kasper

    This paper studies the relationship between macroeconomic fluctuations and corporate defaults while conditioning on industry affiliation and an extensive set of firm-specific factors. By using a panel data set for virtually all incorporated Swedish businesses over 1990-2009, a period which includes

  2. Fluctuating hydrodynamics for ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Lazaridis, Konstantinos [Department of Mathematics and Statistics, Washington State University, Pullman, 99163 (United States); Wickham, Logan [Department of Computer Science, Washington State University, Richland, 99354 (United States); Voulgarakis, Nikolaos, E-mail: n.voulgarakis@wsu.edu [Department of Mathematics and Statistics, Washington State University, Pullman, 99163 (United States)

    2017-04-25

    We present a mean-field fluctuating hydrodynamics (FHD) method for studying the structural and transport properties of ionic liquids in bulk and near electrified surfaces. The free energy of the system consists of two competing terms: (1) a Landau–Lifshitz functional that models the spontaneous separation of the ionic groups, and (2) the standard mean-field electrostatic interaction between the ions in the liquid. The numerical approach used to solve the resulting FHD-Poisson equations is very efficient and models thermal fluctuations with remarkable accuracy. Such density fluctuations are sufficiently strong to excite the experimentally observed spontaneous formation of liquid nano-domains. Statistical analysis of our simulations provides quantitative information about the properties of ionic liquids, such as the mixing quality, stability, and the size of the nano-domains. Our model, thus, can be adequately parameterized by directly comparing our prediction with experimental measurements and all-atom simulations. Conclusively, this work can serve as a practical mathematical tool for testing various theories and designing more efficient mixtures of ionic liquids. - Highlights: • A new fluctuating hydrodynamics method for ionic liquids. • Description of ionic liquid morphology in bulk and near electrified surfaces. • Direct comparison with experimental measurements.

  3. Current status of studies on temperature fluctuation phenomena in LMFRs

    International Nuclear Information System (INIS)

    Ohshima, H.; Muramatsu, T.; Kobayashi, J.; Yamaguchi, A.

    1994-01-01

    This paper describes the current status of studies being performed in PNC on temperature fluctuation phenomena occurring in fast reactors. The studies concentrate on four problems: thermal stratification, thermal striping, core-plenum interaction and free surface sloshing. Both experimental and analytical approaches to reveal these phenomena and to establish design and safety evaluation methods are presented together with future works. (author)

  4. Behavioral flexibility and problem solving in an invasive bird.

    Science.gov (United States)

    Logan, Corina J

    2016-01-01

    Behavioral flexibility is considered an important trait for adapting to environmental change, but it is unclear what it is, how it works, and whether it is a problem solving ability. I investigated behavioral flexibility and problem solving experimentally in great-tailed grackles, an invasive bird species and thus a likely candidate for possessing behavioral flexibility. Grackles demonstrated behavioral flexibility in two contexts, the Aesop's Fable paradigm and a color association test. Contrary to predictions, behavioral flexibility did not correlate across contexts. Four out of 6 grackles exhibited efficient problem solving abilities, but problem solving efficiency did not appear to be directly linked with behavioral flexibility. Problem solving speed also did not significantly correlate with reversal learning scores, indicating that faster learners were not the most flexible. These results reveal how little we know about behavioral flexibility, and provide an immense opportunity for future research to explore how individuals and species can use behavior to react to changing environments.

  5. Organizational flexibility estimation

    OpenAIRE

    Komarynets, Sofia

    2013-01-01

    By the help of parametric estimation the evaluation scale of organizational flexibility and its parameters was formed. Definite degrees of organizational flexibility and its parameters for the Lviv region enterprises were determined. Grouping of the enterprises under the existing scale was carried out. Special recommendations to correct the enterprises behaviour were given.

  6. Reversibly Bistable Flexible Electronics

    KAUST Repository

    Alfaraj, Nasir

    2015-05-01

    Introducing the notion of transformational silicon electronics has paved the way for integrating various applications with silicon-based, modern, high-performance electronic circuits that are mechanically flexible and optically semitransparent. While maintaining large-scale production and prototyping rapidity, this flexible and translucent scheme demonstrates the potential to transform conventionally stiff electronic devices into thin and foldable ones without compromising long-term performance and reliability. In this work, we report on the fabrication and characterization of reversibly bistable flexible electronic switches that utilize flexible n-channel metal-oxide-semiconductor field-effect transistors. The transistors are fabricated initially on rigid (100) silicon substrates before they are peeled off. They can be used to control flexible batches of light-emitting diodes, demonstrating both the relative ease of scaling at minimum cost and maximum reliability and the feasibility of integration. The peeled-off silicon fabric is about 25 µm thick. The fabricated devices are transferred to a reversibly bistable flexible platform through which, for example, a flexible smartphone can be wrapped around a user’s wrist and can also be set back to its original mechanical position. Buckling and cyclic bending of such host platforms brings a completely new dimension to the development of flexible electronics, especially rollable displays.

  7. Flexible magnetoimpidence sensor

    KAUST Repository

    Kavaldzhiev, Mincho

    2015-05-01

    Recently, flexible electronic devices have attracted increasing interest, due to the opportunities they promise for new applications such as wearable devices, where the components are required to flex during normal use[1]. In this light, different magnetic sensors, like microcoil, spin valve, giant magnetoresistance (GMR), magnetoimpedance (MI), have been studied previously on flexible substrates.

  8. Flexibility within Fidelity

    Science.gov (United States)

    Kendall, Philip C.; Gosch, Elizabeth; Furr, Jami M.; Sood, Erica

    2008-01-01

    The authors address concerns regarding manual-based treatments, highlighting the role of flexibility and creativity. A cognitive-behavioral therapy for youth anxiety called the Coping Cat program demonstrates the flexible application of manuals and emphasizes the importance of a child-centered, personalized approach that involves the child in the…

  9. Flexible position probe assembly

    International Nuclear Information System (INIS)

    Schmitz, J.J.

    1977-01-01

    The combination of a plurality of tubular transducer sections and a flexible supporting member extending through the tubular transducer sections forms a flexible elongated probe of a design suitable for monitoring the level of an element, such as a nuclear magnetically permeable control rod or liquid. 3 claims, 23 figures

  10. Edge transport and fluctuation induced turbulence characteristics in early SST-1 plasma

    Energy Technology Data Exchange (ETDEWEB)

    Kakati, B., E-mail: bharat.kakati@ipr.res.in; Pradhan, S., E-mail: pradhan@ipr.res.in; Dhongde, J.; Semwal, P.; Yohan, K.; Banaudha, M.

    2017-02-15

    Highlights: • Anomalous particle transport during the high MHD activity at SST-1. • Electrostatic turbulence is modulated by MHD activity at SST-1 tokamak. • Edge floating potential fluctuations shows poloidal long-range cross correlation. - Abstract: Plasma edge transport characteristics are known to be heavily influenced by the edge fluctuation induced turbulences. These characteristics play a critical role towards the confinement of plasma column in a Tokamak. The edge magnetic fluctuations and its subsequent effect on electrostatic fluctuations have been experimentally investigated for the first time at the edge of the SST-1 plasma column. This paper reports the correlations that exist and is experimentally been observed between the edge densities and floating potential fluctuations with the magnetic fluctuations. The edge density and floating potential fluctuations have been measured with the help of poloidally separated Langmuir probes, whereas the magnetic fluctuations have been measured with poloidally spaced Mirnov coils. Increase in magnetic fluctuations associated with enhanced MHD activities has been found to increase the floating potential and ion saturation current. These observations indicate electrostatic turbulence getting influenced with the MHD activities and reveal the edge anomalous particle transport during SST-1 tokamak discharge. Large-scale coherent structures have been observed in the floating potential fluctuations, indicating long-distance cross correlation in the poloidal directions. From bispectral analysis, a strong nonlinear coupling among the floating potential fluctuations is observed in the low-frequency range about 0–15 kHz.

  11. Flexible Carbon Aerogels

    Directory of Open Access Journals (Sweden)

    Marina Schwan

    2016-09-01

    Full Text Available Carbon aerogels are highly porous materials with a large inner surface area. Due to their high electrical conductivity they are excellent electrode materials in supercapacitors. Their brittleness, however, imposes certain limitations in terms of applicability. In that context, novel carbon aerogels with varying degree of flexibility have been developed. These highly porous, light aerogels are characterized by a high surface area and possess pore structures in the micrometer range, allowing for a reversible deformation of the aerogel network. A high ratio of pore size to particle size was found to be crucial for high flexibility. For dynamic microstructural analysis, compression tests were performed in-situ within a scanning electron microscope allowing us to directly visualize the microstructural flexibility of an aerogel. The flexible carbon aerogels were found to withstand between 15% and 30% of uniaxial compression in a reversible fashion. These findings might stimulate further research and new application fields directed towards flexible supercapacitors and batteries.

  12. Global Sourcing Flexibility

    DEFF Research Database (Denmark)

    Ørberg Jensen, Peter D.; Petersen, Bent

    2013-01-01

    the higher costs (but decreased risk for value chain disruption) embedded in a more flexible global sourcing model that allows the firm to replicate and/or relocate activities across multiple locations. We develop a model and propositions on facilitating and constraining conditions of global sourcing...... sourcing flexibility. Here we draw on prior research in the fields of organizational flexibility, international business and global sourcing as well as case examples and secondary studies. In the second part of the paper, we discuss the implications of global sourcing flexibility for firm strategy...... and operations against the backdrop of the theory-based definition of the construct. We discuss in particular the importance of global sourcing flexibility for operational performance stability, and the trade-off between specialization benefits, emerging from location and service provider specialization, versus...

  13. Factors impeding flexible inpatient unit design.

    Science.gov (United States)

    Pati, Debajyoti; Evans, Jennie; Harvey, Thomas E; Bazuin, Doug

    2012-01-01

    To identify and examine factors extraneous to the design decision-making process that could impede the optimization of flexibility on inpatient units. A 2006 empirical study to identify domains of design decisions that affect flexibility on inpatient units found some indication in the context of the acuity-adaptable operational model that factors extraneous to the design process could have negatively influenced the successful implementation of the model. This raised questions regarding extraneous factors that might influence the successful optimization of flexibility. An exploratory, qualitative method was adopted to examine the question. Stakeholders from five recently built acute care inpatient units participated in the study, which involved three types of data collection: (1) verbal protocol data from a gaming session; (2) in-depth semi-structured interviews; and (3) shadowing frontline personnel. Data collection was conducted between June 2009 and November 2010. The study revealed at least nine factors extraneous to the design process that have the potential to hinder the optimization of flexibility in four domains: (1) systemic; (2) cultural; (3) human; and (4) financial. Flexibility is critical to hospital operations in the new healthcare climate, where cost reduction constitutes a vital target. From this perspective, flexibility and efficiency strategies can be influenced by (1) return on investment, (2) communication, (3) culture change, and (4) problem definition. Extraneous factors identified in this study could also affect flexibility in other care settings; therefore, these findings may be viewed from the overall context of hospital design.

  14. Fluctuation current in superconducting loops

    International Nuclear Information System (INIS)

    Berger, Jorge

    2012-01-01

    A superconducting loop that encloses noninteger flux holds a permanent current. On the average, this current is also present above T c , and has been measured in recent years. We are able to evaluate the permanent current within the TDGL or the Kramer-Watts-Tobin models for loops of general configuration, i.e., we don't require uniform cross section, material or temperature. We can also consider situations in which the width is not negligible in comparison to the radius. Our results agree with experiments. The situations with which we deal at present include fluctuation superconductivity in two-band superconductors, equilibrium thermal fluctuations of supercurrent along a weak link, and ratchet effects.

  15. Fluctuations and confinement in ATF

    International Nuclear Information System (INIS)

    Isler, R.C.; Harris, J.H.; Murakami, M.

    1993-01-01

    In the period immediately prior to the suspension of ATF operation in November, 1991, a great deal of emphasis was palced on investigations of the fundamental mechanisms controlling confinement in this device. At that time, measurements of the density fluctuations throughout the plasma volume indicated the existence of theoretically predicted dissipative trapped electron and resistive interchange instabilities. These identifications were supported by results of dynamic configuration scans of the magnetic fields during which the extent of the magnetic well, shear, and fraction of confined trapped particles were changed continuously. Interpretation of the data from these experiments has been an ongoing exercise. Most recently, analysis of discharges employing strong gas puffing to change density gradients and fluctuation levels have strengthened the view that dissipative trapped electron modes may be present but do not play a significant direct role in energy transport. The present paper summarizes the current understanding concerning the identification of instabilities and their relationship to confinement in ATF

  16. Charge Fluctuations in Nanoscale Capacitors

    Science.gov (United States)

    Limmer, David T.; Merlet, Céline; Salanne, Mathieu; Chandler, David; Madden, Paul A.; van Roij, René; Rotenberg, Benjamin

    2013-09-01

    The fluctuations of the charge on an electrode contain information on the microscopic correlations within the adjacent fluid and their effect on the electronic properties of the interface. We investigate these fluctuations using molecular dynamics simulations in a constant-potential ensemble with histogram reweighting techniques. This approach offers, in particular, an efficient, accurate, and physically insightful route to the differential capacitance that is broadly applicable. We demonstrate these methods with three different capacitors: pure water between platinum electrodes and a pure as well as a solvent-based organic electrolyte each between graphite electrodes. The total charge distributions with the pure solvent and solvent-based electrolytes are remarkably Gaussian, while in the pure ionic liquid the total charge distribution displays distinct non-Gaussian features, suggesting significant potential-driven changes in the organization of the interfacial fluid.

  17. Charge fluctuations in nanoscale capacitors.

    Science.gov (United States)

    Limmer, David T; Merlet, Céline; Salanne, Mathieu; Chandler, David; Madden, Paul A; van Roij, René; Rotenberg, Benjamin

    2013-09-06

    The fluctuations of the charge on an electrode contain information on the microscopic correlations within the adjacent fluid and their effect on the electronic properties of the interface. We investigate these fluctuations using molecular dynamics simulations in a constant-potential ensemble with histogram reweighting techniques. This approach offers, in particular, an efficient, accurate, and physically insightful route to the differential capacitance that is broadly applicable. We demonstrate these methods with three different capacitors: pure water between platinum electrodes and a pure as well as a solvent-based organic electrolyte each between graphite electrodes. The total charge distributions with the pure solvent and solvent-based electrolytes are remarkably Gaussian, while in the pure ionic liquid the total charge distribution displays distinct non-Gaussian features, suggesting significant potential-driven changes in the organization of the interfacial fluid.

  18. Fluctuation theorems and atypical trajectories

    International Nuclear Information System (INIS)

    Sahoo, M; Lahiri, S; Jayannavar, A M

    2011-01-01

    In this work, we have studied simple models that can be solved analytically to illustrate various fluctuation theorems. These fluctuation theorems provide symmetries individually to the distributions of physical quantities such as the classical work (W c ), thermodynamic work (W), total entropy (Δs tot ) and dissipated heat (Q), when the system is driven arbitrarily out of equilibrium. All these quantities can be defined for individual trajectories. We have studied the number of trajectories which exhibit behaviour unexpected at the macroscopic level. As the time of observation increases, the fraction of such atypical trajectories decreases, as expected at the macroscale. The distributions for the thermodynamic work and entropy production in nonlinear models may exhibit a peak (most probable value) in the atypical regime without violating the expected average behaviour. However, dissipated heat and classical work exhibit a peak in the regime of typical behaviour only.

  19. Random numbers from vacuum fluctuations

    International Nuclear Information System (INIS)

    Shi, Yicheng; Kurtsiefer, Christian; Chng, Brenda

    2016-01-01

    We implement a quantum random number generator based on a balanced homodyne measurement of vacuum fluctuations of the electromagnetic field. The digitized signal is directly processed with a fast randomness extraction scheme based on a linear feedback shift register. The random bit stream is continuously read in a computer at a rate of about 480 Mbit/s and passes an extended test suite for random numbers.

  20. Random numbers from vacuum fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Yicheng; Kurtsiefer, Christian, E-mail: christian.kurtsiefer@gmail.com [Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore); Center for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); Chng, Brenda [Center for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore)

    2016-07-25

    We implement a quantum random number generator based on a balanced homodyne measurement of vacuum fluctuations of the electromagnetic field. The digitized signal is directly processed with a fast randomness extraction scheme based on a linear feedback shift register. The random bit stream is continuously read in a computer at a rate of about 480 Mbit/s and passes an extended test suite for random numbers.

  1. Fluctuating asymmetry, sociosexuality, and intrasexual competitive tactics.

    Science.gov (United States)

    Simpson, J A; Gangestad, S W; Christensen, P N; Leck, K

    1999-01-01

    Heterosexual men and women were told they were competing with another same-sex individual for a date with an attractive opposite-sex interviewer. After answering 6 questions, participants were asked to tell the competitor why the interviewer should choose them over the competitor. Participants' videotaped behavior was coded for different behavioral tactics. Men who were more symmetrical and who had a more unrestricted sociosexual orientation were more likely to use direct competition tactics than were less symmetrical and restricted men. Restricted men accentuated their positive personal qualities, presenting themselves as "nice guys." Structural equation modeling revealed that fluctuating asymmetry (FA) was directly associated with the use of direct competition tactics. However, the link between FA and presenting oneself as a nice guy was mediated through sociosexuality. No effects were found for women.

  2. Marketing opportunities for CHP electricity in a virtual power plant. Direct and indirect marketing of flexibility; Vermarktungschancen fuer KWK-Strom im virtuellen Kraftwerk. Direkte und indirekte Flexibilitaetsvermarktung

    Energy Technology Data Exchange (ETDEWEB)

    Otto, Achim; Baumgart, Bastian [Trianel GmbH, Aachen (Germany). Abt. Virtuelle Kraftwerke

    2013-07-15

    The increasingly fluctuating feed-in of electricity by means of a rapid expansion of renewable energies results in an increasing demand for flexible performance for the regulation of production and consumption. An important part of the necessary flexibility could be provided by CHP plants. Their potential of flexibility is not always fully exploited.

  3. Quantifying fluctuations in reversible enzymatic cycles and clocks

    Science.gov (United States)

    Wierenga, Harmen; ten Wolde, Pieter Rein; Becker, Nils B.

    2018-04-01

    Biochemical reactions are fundamentally noisy at a molecular scale. This limits the precision of reaction networks, but it also allows fluctuation measurements that may reveal the structure and dynamics of the underlying biochemical network. Here, we study nonequilibrium reaction cycles, such as the mechanochemical cycle of molecular motors, the phosphorylation cycle of circadian clock proteins, or the transition state cycle of enzymes. Fluctuations in such cycles may be measured using either of two classical definitions of the randomness parameter, which we show to be equivalent in general microscopically reversible cycles. We define a stochastic period for reversible cycles and present analytical solutions for its moments. Furthermore, we associate the two forms of the randomness parameter with the thermodynamic uncertainty relation, which sets limits on the timing precision of the cycle in terms of thermodynamic quantities. Our results should prove useful also for the study of temporal fluctuations in more general networks.

  4. Towards uncovering the structure of power fluctuations of wind farms.

    Science.gov (United States)

    Liu, Huiwen; Jin, Yaqing; Tobin, Nicolas; Chamorro, Leonardo P

    2017-12-01

    The structure of the turbulence-driven power fluctuations in a wind farm is fundamentally described from basic concepts. A derived tuning-free model, supported with experiments, reveals the underlying spectral content of the power fluctuations of a wind farm. It contains two power-law trends and oscillations in the relatively low- and high-frequency ranges. The former is mostly due to the turbulent interaction between the flow and the turbine properties, whereas the latter is due to the advection between turbine pairs. The spectral wind-farm scale power fluctuations Φ_{P} exhibit a power-law decay proportional to f^{-5/3-2} in the region corresponding to the turbulence inertial subrange and at relatively large scales, Φ_{P}∼f^{-2}. Due to the advection and turbulent diffusion of large-scale structures, a spectral oscillation exists with the product of a sinusoidal behavior and an exponential decay in the frequency domain.

  5. Tunneling probe of fluctuating superconductivity in disordered thin films

    Science.gov (United States)

    Dentelski, David; Frydman, Aviad; Shimshoni, Efrat; Dalla Torre, Emanuele G.

    2018-03-01

    Disordered thin films close to the superconductor-insulator phase transition (SIT) hold the key to understanding quantum phase transition in strongly correlated materials. The SIT is governed by superconducting quantum fluctuations, which can be revealed, for example, by tunneling measurements. These experiments detect a spectral gap, accompanied by suppressed coherence peaks, on both sides of the transition. Here we describe the insulating side in terms of a fluctuating superconducting field with finite-range correlations. We perform a controlled diagrammatic resummation and derive analytic expressions for the tunneling differential conductance. We find that short-range superconducting fluctuations suppress the coherence peaks even in the presence of long-range correlations. Our approach offers a quantitative description of existing measurements on disordered thin films and accounts for tunneling spectra with suppressed coherence peaks.

  6. Fluctuation diamagnetism near surfaces and twinning planes in superconductors

    International Nuclear Information System (INIS)

    Burmistrov, S.N.; Dubovskii, L.B.

    1984-01-01

    Fluctuations of the magnetic moment and of the specific heat near surfaces and twinning planes in superconductors are studied. Fluctuations near a surface yield an additional contribution to the effect of the usual bulk fluctuations on the diamagnetic moment. Such an additional contribution has a singularity near a temperature T/sub c/3(H), which is higher than the bulk superconducting transition temperature in a magnetic field T/sub c/2(H). Depending on the strength of the magnetic field, the singularity of the additional contribution to the magnetic moment can be either logarithmic (strong fields) or of square-root type (weak fields). Experiments which could reveal the aforementioned anomalous behavior are discussed in detail

  7. Quantum Fluctuations for Gravitational Impulsive Waves

    OpenAIRE

    Enginer, Y.; Hortacsu, M.; Ozdemir, N.

    1998-01-01

    Quantum fluctuations for a massless scalar field in the background metric of spherical impulsive gravitational waves through Minkowski and de Sitter spaces are investigated. It is shown that there exist finite fluctuations for de Sitter space.

  8. Net charge fluctuations and local charge compensation

    International Nuclear Information System (INIS)

    Fu Jinghua

    2006-01-01

    We propose net charge fluctuation as a measure of local charge correlation length. It is demonstrated that, in terms of a schematic multiperipheral model, net charge fluctuation satisfies the same Quigg-Thomas relation as satisfied by charge transfer fluctuation. Net charge fluctuations measured in finite rapidity windows depend on both the local charge correlation length and the size of the observation window. When the observation window is larger than the local charge correlation length, the net charge fluctuation only depends on the local charge correlation length, while forward-backward charge fluctuations always have strong dependence on the observation window size. Net charge fluctuations and forward-backward charge fluctuations measured in the present heavy ion experiments show characteristic features similar to those from multiperipheral models. But the data cannot all be understood within this simple model

  9. Workplace flexibility: from research to action.

    Science.gov (United States)

    Galinsky, Ellen; Sakai, Kelly; Wigton, Tyler

    2011-01-01

    Ellen Galinsky, Kelly Sakai, and Tyler Wigton explore the "time famine" among American workers-the continuing sense among employees of not having enough time to manage the multiple responsibilities of work and personal and family life. Noting that large shares of U.S. employees report feeling the need for greater workplace flexibility to enable them to take better care of family responsibilities, the authors examine a large-scale community-engagement initiative to increase workplace flexibility voluntarily. Using the 2008 National Study of the Changing Workforce as a primary source of data, the authors begin with an overview of the prevalence of flexibility in today's American workplace. They track which categories of employees have access to various flexibility options, as well as the extent to which employees with access to various types of flexibility use those options. Findings from the study indicate that the majority of employees want flexibility but that access to it varies, with more advantaged employees--those who are well educated, have high salaries, and work full time, for example--being doubly advantaged in having greater access to flexibility. A number of employers, say the authors, tend to be skeptical of the value of workplace flexibility and to fear that employees will abuse it if it is offered. But the study data reveal that most employees use flexibility quite conservatively. When the authors use their nationally representative data set to investigate correlations between access to workplace flexibility and a range of workplace outcomes especially valued by employers--employee engagement, job satisfaction, retention, and health--they find that employers as well as employees can benefit from flexibility. Finally, the authors discuss When Work Works, a large, national community-based initiative under way since 2003 to increase voluntary adoption of workplace flexibility. The authors detail the conceptual basis of the project's design, noting its

  10. Flexible Word Classes

    DEFF Research Database (Denmark)

    • First major publication on the phenomenon • Offers cross-linguistic, descriptive, and diverse theoretical approaches • Includes analysis of data from different language families and from lesser studied languages This book is the first major cross-linguistic study of 'flexible words', i.e. words...... that cannot be classified in terms of the traditional lexical categories Verb, Noun, Adjective or Adverb. Flexible words can - without special morphosyntactic marking - serve in functions for which other languages must employ members of two or more of the four traditional, 'specialised' word classes. Thus......, flexible words are underspecified for communicative functions like 'predicating' (verbal function), 'referring' (nominal function) or 'modifying' (a function typically associated with adjectives and e.g. manner adverbs). Even though linguists have been aware of flexible world classes for more than...

  11. Reversibly Bistable Flexible Electronics

    KAUST Repository

    Alfaraj, Nasir

    2015-01-01

    Introducing the notion of transformational silicon electronics has paved the way for integrating various applications with silicon-based, modern, high-performance electronic circuits that are mechanically flexible and optically semitransparent

  12. Flexibility in insulin prescription

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2016-01-01

    Full Text Available This communication explores the concept of flexibility, a propos insulin preparations and insulin regimes used in the management of type 2 diabetes. The flexibility of an insulin regime or preparation is defined as their ability to be injected at variable times, with variable injection-meal time gaps, in a dose frequency and quantum determined by shared decision making, with a minimal requirement of glucose monitoring and health professional consultation, with no compromise on safety, efficiency and tolerability. The relative flexibility of various basal, prandial and dual action insulins, as well as intensive regimes, is compared. The biopsychosocial model of health is used to assess the utility of different insulins while encouraging a philosophy of flexible insulin usage.

  13. Measurement of magnetic fluctuation induced energy transport

    International Nuclear Information System (INIS)

    Fiksel, G.; Prager, S.C.; Shen, W.; Stoneking, M.

    1993-11-01

    The local electron energy flux produced by magnetic fluctuations has been measured directly in the MST reversed field pinch (over the radial range r/a > 0.75). The flux, produced by electrons traveling parallel to a fluctuating magnetic field, is obtained from correlation between the fluctuations in the parallel heat flux and the radial magnetic field. The fluctuation induced flux is large (100 kW/cm 2 ) in the ''core'' (r/a 2 ) in the edge

  14. Flexible displays, rigid designs?

    DEFF Research Database (Denmark)

    Hornbæk, Kasper

    2015-01-01

    Rapid technological progress has enabled a wide range of flexible displays for computing devices, but the user experience--which we're only beginning to understand--will be the key driver for successful designs.......Rapid technological progress has enabled a wide range of flexible displays for computing devices, but the user experience--which we're only beginning to understand--will be the key driver for successful designs....

  15. The study of RMB exchange rate complex networks based on fluctuation mode

    Science.gov (United States)

    Yao, Can-Zhong; Lin, Ji-Nan; Zheng, Xu-Zhou; Liu, Xiao-Feng

    2015-10-01

    In the paper, we research on the characteristics of RMB exchange rate time series fluctuation with methods of symbolization and coarse gaining. First, based on fluctuation features of RMB exchange rate, we define the first type of fluctuation mode as one specific foreign currency against RMB in four days' fluctuating situations, and the second type as four different foreign currencies against RMB in one day's fluctuating situation. With the transforming method, we construct the unique-currency and multi-currency complex networks. Further, through analyzing the topological features including out-degree, betweenness centrality and clustering coefficient of fluctuation-mode complex networks, we find that the out-degree distribution of both types of fluctuation mode basically follows power-law distributions with exponents between 1 and 2. The further analysis reveals that the out-degree and the clustering coefficient generally obey the approximated negative correlation. With this result, we confirm previous observations showing that the RMB exchange rate exhibits a characteristic of long-range memory. Finally, we analyze the most probable transmission route of fluctuation modes, and provide probability prediction matrix. The transmission route for RMB exchange rate fluctuation modes exhibits the characteristics of partially closed loop, repeat and reversibility, which lays a solid foundation for predicting RMB exchange rate fluctuation patterns with large volume of data.

  16. Giant current fluctuations in an overheated single-electron transistor

    Science.gov (United States)

    Laakso, M. A.; Heikkilä, T. T.; Nazarov, Yuli V.

    2010-11-01

    Interplay of cotunneling and single-electron tunneling in a thermally isolated single-electron transistor leads to peculiar overheating effects. In particular, there is an interesting crossover interval where the competition between cotunneling and single-electron tunneling changes to the dominance of the latter. In this interval, the current exhibits anomalous sensitivity to the effective electron temperature of the transistor island and its fluctuations. We present a detailed study of the current and temperature fluctuations at this interesting point. The methods implemented allow for a complete characterization of the distribution of the fluctuating quantities, well beyond the Gaussian approximation. We reveal and explore the parameter range where, for sufficiently small transistor islands, the current fluctuations become gigantic. In this regime, the optimal value of the current, its expectation value, and its standard deviation differ from each other by parametrically large factors. This situation is unique for transport in nanostructures and for electron transport in general. The origin of this spectacular effect is the exponential sensitivity of the current to the fluctuating effective temperature.

  17. Analysis of dynamic multiplicity fluctuations at PHOBOS

    Science.gov (United States)

    Chai, Zhengwei; PHOBOS Collaboration; Back, B. B.; Baker, M. D.; Ballintijn, M.; Barton, D. S.; Betts, R. R.; Bickley, A. A.; Bindel, R.; Budzanowski, A.; Busza, W.; Carroll, A.; Chai, Z.; Decowski, M. P.; García, E.; George, N.; Gulbrandsen, K.; Gushue, S.; Halliwell, C.; Hamblen, J.; Heintzelman, G. A.; Henderson, C.; Hofman, D. J.; Hollis, R. S.; Holynski, R.; Holzman, B.; Iordanova, A.; Johnson, E.; Kane, J. L.; Katzy, J.; Khan, N.; Kucewicz, W.; Kulinich, P.; Kuo, C. M.; Lin, W. T.; Manly, S.; McLeod, D.; Mignerey, A. C.; Nouicer, R.; Olszewski, A.; Pak, R.; Park, I. C.; Pernegger, H.; Reed, C.; Remsberg, L. P.; Reuter, M.; Roland, C.; Roland, G.; Rosenberg, L.; Sagerer, J.; Sarin, P.; Sawicki, P.; Skulski, W.; Steinberg, P.; Stephans, G. S. F.; Sukhanov, A.; Tang, J. L.; Trzupek, A.; Vale, C.; van Nieuwenhuizen, G. J.; Verdier, R.; Wolfs, F. L. H.; Wosiek, B.; Wozniak, K.; Wuosmaa, A. H.; Wyslouch, B.

    2005-01-01

    This paper presents the analysis of the dynamic fluctuations in the inclusive charged particle multiplicity measured by PHOBOS for Au+Au collisions at surdsNN = 200GeV within the pseudo-rapidity range of -3 < η < 3. First the definition of the fluctuations observables used in this analysis is presented, together with the discussion of their physics meaning. Then the procedure for the extraction of dynamic fluctuations is described. Some preliminary results are included to illustrate the correlation features of the fluctuation observable. New dynamic fluctuations results will be available in a later publication.

  18. Noise and fluctuations an introduction

    CERN Document Server

    MacDonald, D K C

    2006-01-01

    An understanding of fluctuations and their role is both useful and fundamental to the study of physics. This concise study of random processes offers graduate students and research physicists a survey that encompasses both the relationship of Brownian Movement with statistical mechanics and the problem of irreversible processes. It outlines the basics of the physics involved, without the strictures of mathematical rigor.The three-part treatment starts with a general survey of Brownian Movement, including electrical Brownian Movement and ""shot-noise,"" Part two explores correlation, frequency

  19. Electrostatic fluctuations in soap films

    International Nuclear Information System (INIS)

    Dean, D.S.; Horgan, R.R.

    2002-01-01

    A field theory to describe electrostatic interactions in soap films, described by electric multilayers with a generalized thermodynamic surface-charging mechanism, is studied. In the limit where the electrostatic interactions are weak, this theory is exactly soluble. The theory incorporates in a consistent way, the surface-charging mechanism and the fluctuations in the electrostatic field that correspond to the zero-frequency component of the van der Waals force. It is shown that these terms lead to a Casimir-like attraction that can be sufficiently large to explain the transition between the common black film to a Newton black film

  20. Chaotic fluctuations in mathematical economics

    Energy Technology Data Exchange (ETDEWEB)

    Yoshida, Hiroyuki, E-mail: yoshida.hiroyuki@nihon-u.ac.jp [College of Economics, Nihon University, Chiyoda-ku, Tokyo 101-8360 (Japan)

    2011-03-01

    In this paper we examine a Cournot duopoly model, which expresses the strategic interaction between two firms. We formulate the dynamic adjustment process and investigate the dynamic properties of the stationary point. By introducing a memory mechanism characterized by distributed lag functions, we presuppose that each firm makes production decisions in a cautious manner. This implies that we have to deal with the system of integro-differential equations. By means of numerical simulations we show the occurrence of chaotic fluctuations in the case of fixed delays.

  1. An Objective Fluctuation Score for Parkinson's Disease

    Science.gov (United States)

    Horne, Malcolm K.; McGregor, Sarah; Bergquist, Filip

    2015-01-01

    Introduction Establishing the presence and severity of fluctuations is important in managing Parkinson’s Disease yet there is no reliable, objective means of doing this. In this study we have evaluated a Fluctuation Score derived from variations in dyskinesia and bradykinesia scores produced by an accelerometry based system. Methods The Fluctuation Score was produced by summing the interquartile range of bradykinesia scores and dyskinesia scores produced every 2 minutes between 0900-1800 for at least 6 days by the accelerometry based system and expressing it as an algorithm. Results This Score could distinguish between fluctuating and non-fluctuating patients with high sensitivity and selectivity and was significant lower following activation of deep brain stimulators. The scores following deep brain stimulation lay in a band just above the score separating fluctuators from non-fluctuators, suggesting a range representing adequate motor control. When compared with control subjects the score of newly diagnosed patients show a loss of fluctuation with onset of PD. The score was calculated in subjects whose duration of disease was known and this showed that newly diagnosed patients soon develop higher scores which either fall under or within the range representing adequate motor control or instead go on to develop more severe fluctuations. Conclusion The Fluctuation Score described here promises to be a useful tool for identifying patients whose fluctuations are progressing and may require therapeutic changes. It also shows promise as a useful research tool. Further studies are required to more accurately identify therapeutic targets and ranges. PMID:25928634

  2. The value of flexibility in power markets

    International Nuclear Information System (INIS)

    Goutte, Stephane; Vassilopoulos, Philippe

    2017-01-01

    In this paper we attempt to quantify the net revenues that can be captured by a flexible resource able to react to the short term price variations on the day-ahead and intra-day markets in Germany. We find that the difference between day-ahead and intra-day revenues for a flexible resource has been increasing (although the profitability has been decreasing on both markets). This difference is more pronounced once 15 mn price variations can be captured by a flexible resource. The net revenues from the local 15 mn auction (which is held 3 hours after the hourly 'coupled' day-ahead auction) are more than eight times higher than the day-ahead hourly auction but below the net revenues that can be captured with the high prices from the continuous market. The results of the backward-looking empirical estimations allow us to distinguish and quantify two components of flexibility: (1) the 'immediacy' value as we are approaching real-time and the urgency of the delivery increases (this value is revealed during the continuous intra-day process and is highly linked to the stochastic nature of power supply and demand (i.e. wind/solar forecasts, forced outages of thermal generation,...) forecast error risk), and (2) the 'flexibility' component as a resource can react to variations of shorter granularity (15 mn Vs 60 mn). We model and quantify the 'flexibility' component. (authors)

  3. A Taxonomy for Modeling Flexibility and a Computationally Efficient Algorithm for Dispatch in Smart Grids

    DEFF Research Database (Denmark)

    Petersen, Mette Højgaard; Edlund, Kristian; Hansen, Lars Henrik

    2013-01-01

    The word flexibility is central to Smart Grid literature, but still a formal definition of flexibility is pending. This paper present a taxonomy for flexibility modeling denoted Buckets, Batteries and Bakeries. We consider a direct control Virtual Power Plant (VPP), which is given the task...... of servicing a portfolio of flexible consumers by use of a fluctuating power supply. Based on the developed taxonomy we first prove that no causal optimal dispatch strategies exist for the considered problem. We then present two heuristic algorithms for solving the balancing task: Predictive Balancing...

  4. Flexible transparent electrode

    Science.gov (United States)

    Demiryont, Hulya; Shannon, Kenneth C., III; Moorehead, David; Bratcher, Matthew

    2011-06-01

    This paper presents the properties of the EclipseTECTM transparent conductor. EclipseTECTM is a room temperature deposited nanostructured thin film coating system comprised of metal-oxide semiconductor elements. The system possesses metal-like conductivity and glass-like transparency in the visible region. These highly conductive TEC films exhibit high shielding efficiency (35dB at 1 to 100GHz). EclipseTECTM can be deposited on rigid or flexible substrates. For example, EclipseTECTM deposited on polyethylene terephthalate (PET) is extremely flexible that can be rolled around a 9mm diameter cylinder with little or no reduction in electrical conductivity and that can assume pre-extension states after an applied stress is relieved. The TEC is colorless and has been tailored to have high visible transmittance which matches the eye sensitivity curve and allows the viewing of true background colors through the coating. EclipseTECTM is flexible, durable and can be tailored at the interface for applications such as electron- or hole-injecting OLED electrodes as well as electrodes in flexible displays. Tunable work function and optical design flexibility also make EclipseTECTM well-suited as a candidate for grid electrode replacement in next-generation photovoltaic cells.

  5. Flexible magnetoimpedance sensor

    International Nuclear Information System (INIS)

    Li, Bodong; Kavaldzhiev, Mincho N.; Kosel, Jürgen

    2015-01-01

    Flexible magnetoimpedance (MI) sensors fabricated using a NiFe/Cu/NiFe tri-layer on Kapton substrate have been studied. A customized flexible microstrip transmission line was employed to investigate the MI sensors's magnetic field and frequency responses and their dependence on the sensors's deflection. For the first time, the impedance characteristic is obtained through reflection coefficient analysis over a wide range of frequencies from 0.1 MHz to 3 GHz and for deflections ranging from zero curvature to a radius of 7.2 cm. The sensor element maintains a high MI ratio of up to 90% and magnetic sensitivity of up to 9.2%/Oe over different bending curvatures. The relationship between the curvature and material composition is discussed based on the magnetostriction effect and stress simulations. The sensor's large frequency range, simple fabrication process and high sensitivity provide a great potential for flexible electronics and wireless applications. - Highlights: • A flexible magnetoimpedance (MI) sensor is developed. • Studies are carried out using a flexible microstrip transmission line. • An MI ratio of up to 90% is obtained. • The effect of magnetostriction is studied

  6. Education for Flexible Personality

    Directory of Open Access Journals (Sweden)

    Bogomir Novak

    1998-12-01

    Full Text Available Flexible personality transforms both cultural environment and itself. Post-modern personality is both contemplative and active. On one hand, it is subject to inner imagination of a creative act, and on the other hand, to creation of a tangible product What is more, flexible personality is also autonomous, mature, healthy and well balanced, as well as stable and responsive to the demand for change. Due to ever quicker changes, flexible personality is a must. And it is a task. The impact of professional work of adults on the education of children, however, is being conditioned by the exrigid family and rigid enterprises or institutions in which adults are employed. Nevertheless, flexible educational style is not repressive, as it used to be, nor permissive and totally concentrated on the child. It is a choice between the two qualities. The educators' style is dependent on their attitude towards life (play and self-education and not only towards work. Nowadays, flexibility is a way towards quality management of social and personal changes.

  7. Flexible Foam Model.

    Energy Technology Data Exchange (ETDEWEB)

    Neilsen, Michael K.; Lu, Wei-Yang; Werner, Brian T.; Scherzinger, William M.; Lo, Chi S.

    2018-03-01

    Experiments were performed to characterize the mechanical response of a 15 pcf flexible polyurethane foam to large deformation at different strain rates and temperatures. Results from these experiments indicated that at room temperature, flexible polyurethane foams exhibit significant nonlinear elastic deformation and nearly return to their original undeformed shape when unloaded. However, when these foams are cooled to temperatures below their glass transition temperature of approximately -35 o C, they behave like rigid polyurethane foams and exhibit significant permanent deformation when compressed. Thus, a new model which captures this dramatic change in behavior with temperature was developed and implemented into SIERRA with the name Flex_Foam to describe the mechanical response of both flexible and rigid foams to large deformation at a variety of temperatures and strain rates. This report includes a description of recent experiments. Next, development of the Flex Foam model for flexible polyurethane and other flexible foams is described. Selection of material parameters are discussed and finite element simulations with the new Flex Foam model are compared with experimental results to show behavior that can be captured with this new model.

  8. Currency speculation and dollar fluctuations

    Directory of Open Access Journals (Sweden)

    Stephan Schulmeister

    1988-12-01

    Full Text Available In this study the reasons behind the wide fluctuations of the dollar exchange rate following the breakdown of the Bretton Woods system, for the most part unexplained by the prevailing exchange rate theories, are explored. To do so, the author investigates the exchange rate between the two most traded currencies, the dollar and the deutschemark, from 1973 to 1988. In the first part, the pattern of the daily exchange rate movements is examined to show that a sequence of upward and downward trends interrupted by non-directional movements is typical of exchange rate dynamics in the short run. Moreover, this pattern is systemically exploited through currency speculation, particularly through the use of “technical analysis”. In the second part, the author focuses on the medium-term, arguing that fluctuations can be explained as the result of interacting disequilibria in the goods and asset markets. Although currency speculation has been systemically profitable for most currencies, it should be considered to be destabilizing since the sequence of price runs caused large and persistent deviations of exchange rates from their equilibrium values (purchasing power parity.

  9. Universal bounds on current fluctuations.

    Science.gov (United States)

    Pietzonka, Patrick; Barato, Andre C; Seifert, Udo

    2016-05-01

    For current fluctuations in nonequilibrium steady states of Markovian processes, we derive four different universal bounds valid beyond the Gaussian regime. Different variants of these bounds apply to either the entropy change or any individual current, e.g., the rate of substrate consumption in a chemical reaction or the electron current in an electronic device. The bounds vary with respect to their degree of universality and tightness. A universal parabolic bound on the generating function of an arbitrary current depends solely on the average entropy production. A second, stronger bound requires knowledge both of the thermodynamic forces that drive the system and of the topology of the network of states. These two bounds are conjectures based on extensive numerics. An exponential bound that depends only on the average entropy production and the average number of transitions per time is rigorously proved. This bound has no obvious relation to the parabolic bound but it is typically tighter further away from equilibrium. An asymptotic bound that depends on the specific transition rates and becomes tight for large fluctuations is also derived. This bound allows for the prediction of the asymptotic growth of the generating function. Even though our results are restricted to networks with a finite number of states, we show that the parabolic bound is also valid for three paradigmatic examples of driven diffusive systems for which the generating function can be calculated using the additivity principle. Our bounds provide a general class of constraints for nonequilibrium systems.

  10. Niche acclimatization in Red Sea corals is dependent on flexibility of host-symbiont association

    KAUST Repository

    Ziegler, Maren

    2015-08-06

    Knowledge of host-symbiont specificity and acclimatization capacity of corals is crucial for understanding implications of environmental change. Whilst some corals have been shown to associate with a number of symbionts that may comprise different physiologies, most corals associate with only one dominant Symbiodinium species at a time. Coral communities in the Red Sea thrive under large fluctuations of environmental conditions, but the degree and mechanisms of coral acclimatization are largely unexplored. Here we investigated the potential for niche acclimatization in 2 dominant corals from the central Red Sea, Pocillopora verrucosa and Porites lutea, in relation to the fidelity of the underlying coral-symbiont association. Repeated sampling over 2 seasons along a cross-shelf and depth gradient revealed a stable symbiont association in P. verrucosa and flexible association in P. lutea. A statistical biological-environmental matching routine revealed that the high plasticity of photophysiology and photopigments in the stable Symbiodinium microadriaticum (type A1) community in P. verrucosa were correlated with environmental influences along spatio-temporal dimensions. In contrast, photophysiology and pigments were less variable within each symbiont type from P. lutea indicating that niche acclimatization was rather regulated by a flexible association with a variable Symbiodinium community. Based on these data, we advocate an extended concept of phenotypic plasticity of the coral holobiont, in which the scleractinian host either associates with a specific Symbiodinium type with a broad physiological tolerance, or the host-symbiont pairing is more flexible to accommodate for different symbiont associations, each adapted to specific environmental settings.

  11. Niche acclimatization in Red Sea corals is dependent on flexibility of host-symbiont association

    KAUST Repository

    Ziegler, Maren; Roder, Cornelia; Bü chel, C; Voolstra, Christian R.

    2015-01-01

    Knowledge of host-symbiont specificity and acclimatization capacity of corals is crucial for understanding implications of environmental change. Whilst some corals have been shown to associate with a number of symbionts that may comprise different physiologies, most corals associate with only one dominant Symbiodinium species at a time. Coral communities in the Red Sea thrive under large fluctuations of environmental conditions, but the degree and mechanisms of coral acclimatization are largely unexplored. Here we investigated the potential for niche acclimatization in 2 dominant corals from the central Red Sea, Pocillopora verrucosa and Porites lutea, in relation to the fidelity of the underlying coral-symbiont association. Repeated sampling over 2 seasons along a cross-shelf and depth gradient revealed a stable symbiont association in P. verrucosa and flexible association in P. lutea. A statistical biological-environmental matching routine revealed that the high plasticity of photophysiology and photopigments in the stable Symbiodinium microadriaticum (type A1) community in P. verrucosa were correlated with environmental influences along spatio-temporal dimensions. In contrast, photophysiology and pigments were less variable within each symbiont type from P. lutea indicating that niche acclimatization was rather regulated by a flexible association with a variable Symbiodinium community. Based on these data, we advocate an extended concept of phenotypic plasticity of the coral holobiont, in which the scleractinian host either associates with a specific Symbiodinium type with a broad physiological tolerance, or the host-symbiont pairing is more flexible to accommodate for different symbiont associations, each adapted to specific environmental settings.

  12. Natural flexible dermal armor.

    Science.gov (United States)

    Yang, Wen; Chen, Irene H; Gludovatz, Bernd; Zimmermann, Elizabeth A; Ritchie, Robert O; Meyers, Marc A

    2013-01-04

    Fish, reptiles, and mammals can possess flexible dermal armor for protection. Here we seek to find the means by which Nature derives its protection by examining the scales from several fish (Atractosteus spatula, Arapaima gigas, Polypterus senegalus, Morone saxatilis, Cyprinius carpio), and osteoderms from armadillos, alligators, and leatherback turtles. Dermal armor has clearly been developed by convergent evolution in these different species. In general, it has a hierarchical structure with collagen fibers joining more rigid units (scales or osteoderms), thereby increasing flexibility without significantly sacrificing strength, in contrast to rigid monolithic mineral composites. These dermal structures are also multifunctional, with hydrodynamic drag (in fish), coloration for camouflage or intraspecies recognition, temperature and fluid regulation being other important functions. The understanding of such flexible dermal armor is important as it may provide a basis for new synthetic, yet bioinspired, armor materials. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Flexible magnetoimpedance sensor

    KAUST Repository

    Li, Bodong

    2015-03-01

    Flexible magnetoimpedance (MI) sensors fabricated using a NiFe/Cu/NiFe tri-layer on Kapton substrate have been studied. A customized flexible microstrip transmission line was employed to investigate the MI sensors\\'s magnetic field and frequency responses and their dependence on the sensors\\'s deflection. For the first time, the impedance characteristic is obtained through reflection coefficient analysis over a wide range of frequencies from 0.1 MHz to 3 GHz and for deflections ranging from zero curvature to a radius of 7.2 cm. The sensor element maintains a high MI ratio of up to 90% and magnetic sensitivity of up to 9.2%/Oe over different bending curvatures. The relationship between the curvature and material composition is discussed based on the magnetostriction effect and stress simulations. The sensor\\'s large frequency range, simple fabrication process and high sensitivity provide a great potential for flexible electronics and wireless applications.

  14. Software industrial flexible

    OpenAIRE

    Díaz Araya, Daniel; Muñoz, Leandro; Sirerol, Daniel; Oviedo, Sandra; Ibáñez, Francisco S.

    2012-01-01

    En este trabajo se pretende investigar y proponer técnicas, métodos y tecnologías que permitan el desarrollo de software flexible en ambientes industriales. El objetivo es generar métodos y técnicas para facilitar el desarrollo de software flexible en ambientes industriales. Las áreas de investigación son los sistemas de scheduling de producción, la generación de software para plataformas de hardware abiertas y la innovación.

  15. Production Flexibility and Hedging

    Directory of Open Access Journals (Sweden)

    Georges Dionne

    2015-12-01

    Full Text Available We extend the analysis on hedging with price and output uncertainty by endogenizing the output decision. Specifically, we consider the joint determination of output and hedging in the case of flexibility in production. We show that the risk-averse firm always maintains a short position in the futures market when the futures price is actuarially fair. Moreover, in the context of an example, we show that the presence of production flexibility reduces the incentive to hedge for all risk averse agents.

  16. The flexibility of flexicurity

    DEFF Research Database (Denmark)

    Jensen, Carsten Strøby

    2011-01-01

    by a special relation between flexibility, social security and active labour market policy, where a high level of social security is seen as a precondition for a labour market characterized by flexibility. In this article it is argued that the Danish labour market is characterized by having not just one model...... of flexicurity, but two. These two models cover different parts of the labour market and different segments of employees. The first model (the blue-collar flexicurity model) – the one that is often focused on in the literature – covers primarily skilled and unskilled workers on the labour market. The second...

  17. Ras activation by SOS: Allosteric regulation by altered fluctuation dynamics

    Science.gov (United States)

    Iversen, Lars; Tu, Hsiung-Lin; Lin, Wan-Chen; Christensen, Sune M.; Abel, Steven M.; Iwig, Jeff; Wu, Hung-Jen; Gureasko, Jodi; Rhodes, Christopher; Petit, Rebecca S.; Hansen, Scott D.; Thill, Peter; Yu, Cheng-Han; Stamou, Dimitrios; Chakraborty, Arup K.; Kuriyan, John; Groves, Jay T.

    2014-01-01

    Activation of the small guanosine triphosphatase H-Ras by the exchange factor Son of Sevenless (SOS) is an important hub for signal transduction. Multiple layers of regulation, through protein and membrane interactions, govern activity of SOS. We characterized the specific activity of individual SOS molecules catalyzing nucleotide exchange in H-Ras. Single-molecule kinetic traces revealed that SOS samples a broad distribution of turnover rates through stochastic fluctuations between distinct, long-lived (more than 100 seconds), functional states. The expected allosteric activation of SOS by Ras–guanosine triphosphate (GTP) was conspicuously absent in the mean rate. However, fluctuations into highly active states were modulated by Ras-GTP. This reveals a mechanism in which functional output may be determined by the dynamical spectrum of rates sampled by a small number of enzymes, rather than the ensemble average. PMID:24994643

  18. Hydrodynamical fluctuations in smooth shear flows

    International Nuclear Information System (INIS)

    Chagelishvili, G.D.; Khujadze, G.R.; Lominadze, J.G.

    1999-11-01

    Background of hydrodynamical fluctuations in a intrinsically/stochastically forced, laminar, uniform shear flow is studied. The employment of so-called nonmodal mathematical analysis makes it possible to represent the background of fluctuations in a new light and to get more insight into the physics of its formation. The basic physical processes responsible for the formation of vortex and acoustic wave fluctuation backgrounds are analyzed. Interplay of the processes at low and moderate shear rates is described. Three-dimensional vortex fluctuations around a given macroscopic state are numerically calculated. The correlation functions of the fluctuations of physical quantities are analyzed. It is shown that there exists subspace D k in the wave-number space (k-space) that is limited externally by spherical surface with radius k ν ≡ A/ν (where A is the velocity shear parameter, ν - the kinematic viscosity) in the nonequilibrium open system under study. The spatial Fourier harmonics of vortex as well as acoustic wave fluctuations are strongly subjected by flow shear (by the open character of the system) at wave-numbers satisfying the condition k ν . Specifically it is shown that in D k : The fluctuations are non-Markovian; the spatial spectral density of energy of the vortex fluctuations by far exceeds the white-noise; the term of a new type associated to the hydrodynamical fluctuation of velocity appears in the correlation function of pressure; the fluctuation background of the acoustic waves is completely different at low and moderate shear rates (at low shear rates it is reduced in D k in comparison to the uniform (non-shear) flow; at moderate shear rates it it comparable to the background of the vortex fluctuations). The fluctuation background of both the vortex and the acoustic wave modes is anisotropic. The possible significance of the fluctuation background of vortices for the subcritical transition to turbulence and Brownian motion of small macroscopic

  19. Flexibility of syntrophic enzyme systems in Desulfovibrio species ensures their adaptation capability to environmental changes.

    Science.gov (United States)

    Meyer, Birte; Kuehl, Jennifer V; Deutschbauer, Adam M; Arkin, Adam P; Stahl, David A

    2013-11-01

    The mineralization of organic matter in anoxic environments relies on the cooperative activities of hydrogen producers and consumers obligately linked by interspecies metabolite exchange in syntrophic consortia that may include sulfate reducing species such as Desulfovibrio. To evaluate the metabolic flexibility of syntrophic Desulfovibrio to adapt to naturally fluctuating methanogenic environments, we studied Desulfovibrio alaskensis strain G20 grown in chemostats under respiratory and syntrophic conditions with alternative methanogenic partners, Methanococcus maripaludis and Methanospirillum hungatei, at different growth rates. Comparative whole-genome transcriptional analyses, complemented by G20 mutant strain growth experiments and physiological data, revealed a significant influence of both energy source availability (as controlled by dilution rate) and methanogen on the electron transfer systems, ratios of interspecies electron carriers, energy generating systems, and interspecies physical associations. A total of 68 genes were commonly differentially expressed under syntrophic versus respiratory lifestyle. Under low-energy (low-growth-rate) conditions, strain G20 further had the capacity to adapt to the metabolism of its methanogenic partners, as shown by its differing gene expression of enzymes involved in the direct metabolic interactions (e.g., periplasmic hydrogenases) and the ratio shift in electron carriers used for interspecies metabolite exchange (hydrogen/formate). A putative monomeric [Fe-Fe] hydrogenase and Hmc (high-molecular-weight-cytochrome c3) complex-linked reverse menaquinone (MQ) redox loop become increasingly important for the reoxidation of the lactate-/pyruvate oxidation-derived redox pair, DsrC(red) and Fd(red), relative to the Qmo-MQ-Qrc (quinone-interacting membrane-bound oxidoreductase; quinone-reducing complex) loop. Together, these data underscore the high enzymatic and metabolic adaptive flexibility that likely sustains

  20. Multifractal Detrended Fluctuation Analysis of Human gait Diseases

    Directory of Open Access Journals (Sweden)

    Srimonti eDutta

    2013-10-01

    Full Text Available IIn this paper multifractal detrended fluctuation analysis is used to study the human gait time series for normal and diseased sets. It is observed that long range correlation is primarily responsible for the origin of multifractality. The study reveals that the degree of multifractality is more for normal set compared to diseased set. However the method fails to distinguish between the two diseased sets.

  1. Interplay between endogenous and exogenous fluctuations in financial markets

    OpenAIRE

    Gontis, Vygintas

    2016-01-01

    We address microscopic, agent based, and macroscopic, stochastic, modeling of the financial markets combining it with the exogenous noise. The interplay between the endogenous dynamics of agents and the exogenous noise is the primary mechanism responsible for the observed long-range dependence and statistical properties of high volatility return intervals. By exogenous noise we mean information flow or/and order flow fluctuations. Numerical results based on the proposed model reveal that the ...

  2. Fluctuating hyperfine interactions: computational implementation

    International Nuclear Information System (INIS)

    Zacate, M. O.; Evenson, W. E.

    2010-01-01

    A library of computational routines has been created to assist in the analysis of stochastic models of hyperfine interactions. We call this library the stochastic hyperfine interactions modeling library (SHIML). It provides routines written in the C programming language that (1) read a text description of a model for fluctuating hyperfine fields, (2) set up the Blume matrix, upon which the evolution operator of the system depends, and (3) find the eigenvalues and eigenvectors of the Blume matrix so that theoretical spectra of experimental hyperfine interaction measurements can be calculated. Example model calculations are included in the SHIML package to illustrate its use and to generate perturbed angular correlation spectra for the special case of polycrystalline samples when anisotropy terms of higher order than A 22 can be neglected.

  3. Fluctuating nonlinear hydrodynamics of flocking

    Science.gov (United States)

    Yadav, Sunil Kumar; Das, Shankar P.

    2018-03-01

    Starting from a microscopic model, the continuum field theoretic description of the dynamics of a system of active ingredients or "particles" is presented. The equations of motion for the respective collective densities of mass and momentum follow exactly from that of a single element in the flock. The single-particle dynamics has noise and anomalous momentum dependence in its frictional terms. The equations for the collective densities are averaged over a local equilibrium distribution to obtain the corresponding coarse grained equations of fluctuating nonlinear hydrodynamics (FNH). The latter are the equations used frequently for describing active systems on the basis of intuitive arguments. The transport coefficients which appear in the macroscopic FNH equations are determined in terms of the parameters of the microscopic dynamics.

  4. Diffusion of flexible, charged, nanoscopic molecules in solution: Size and pH dependence for PAMAM dendrimer

    Science.gov (United States)

    Maiti, Prabal K.; Bagchi, Biman

    2009-12-01

    In order to understand self-diffusion (D) of a charged, flexible, and porous nanoscopic molecule in water, we carry out very long, fully atomistic molecular dynamics simulation of PAMAM dendrimer up to eight generations in explicit salt water under varying pH. We find that while the radius of gyration (Rg) varies as N1/3, the self-diffusion constant (D ) scales, surprisingly, as N-α, with α =0.39 at high pH and 0.5 at neutral pH, indicating a dramatic breakdown of Stokes-Einstein relation for diffusion of charged nanoscopic molecules. The variation in D as a function of radius of gyration demonstrates the importance of treating water and ions explicitly in the diffusion process of a flexible nanoscopic molecule. In agreement with recent experiments, the self-diffusion constant increases with pH, revealing the importance of dielectric friction in the diffusion process. The shape of a dendrimer is found to fluctuate on a nanosecond time scale. We argue that this flexibility (and also the porosity) of the dendrimer may play an important role in determining the mean square displacement of the dendrimer and the breakdown of the Stokes-Einstein relation between diffusion constant and the radius.

  5. Flexibility as a service

    NARCIS (Netherlands)

    Aalst, van der W.M.P.; Adams, M.; Hofstede, ter A.H.M.; Pesic, M.; Schonenberg, H.; Chen, L.; Liu, C.; Liu, Q.; Deng, K.

    2009-01-01

    The lack of flexibility is often seen as an inhibitor for the successful application of workflow technology. Many researchers have proposed different ways of addressing this problem and some of these ideas have been implemented in commercial systems. However, a "one size fits all" approach is likely

  6. Valuing Flexibility. Phase 2

    Science.gov (United States)

    2012-10-29

    Quarterly (2): 38-49. Cormier, P., Olewnik, A., and Lewis, K. 2008. An Approach to Quantifying Design Flexibility for Mass Customization in Early...C. Clarkson, P., and Zanker, W. 2004. Change and customisation in complex engineering domains, Res Eng Des 15(1), 1–21. Ekstrom, M. and Bjornsson, H

  7. Flexible Query Answering Systems

    DEFF Research Database (Denmark)

    This book constitutes the refereed proceedings of the 12th International Conference on Flexible Query Answering Systems, FQAS 2017, held in London, UK, in June 2017. The 21 full papers presented in this book together with 4 short papers were carefully reviewed and selected from 43 submissions...

  8. Flexible metal bellows

    CERN Multimedia

    CERN PhotoLab

    1975-01-01

    A set of flexible metal bellows being fatigue-tested by repeated offset motion. Such bellows assemblies were used in the SPS vacuum system at places where , for instance, beam stoppers and collimators had to be moved frequently in and out of the beam path.

  9. Flexible energy systems

    DEFF Research Database (Denmark)

    Lund, Henrik

    2003-01-01

    The paper discusses and analyses diffent national strategies and points out key changes in the energy system in order to achieve a system which can benefit from a high percentage of wind and CHP without having surplus production problems, introduced here as a flexible energy system....

  10. A flexible WLAN receiver

    NARCIS (Netherlands)

    Schiphorst, Roelof; Hoeksema, F.W.; Slump, Cornelis H.

    2003-01-01

    Flexible radio receivers are also called Software Defined Radios (SDRs) [1], [2]. The focus of our SDR project [3] is on designing the front end, from antenna to demodulation in bits, of a °exible, multi-standard WLAN receiver. We try to combine an instance of a (G)FSK receiver (Bluetooth) with an

  11. Interplanetary Alfvenic fluctuations: A stochastic model

    International Nuclear Information System (INIS)

    Barnes, A.

    1981-01-01

    The strong alignment of the average directions of minimum magnetic variance and mean magnetic field in interplanetary Alfvenic fluctuations is inconsistent with the usual wave-propagation models. We investigate the concept of minimum variance for nonplanar Alfvenic fluctuations in which the field direction varies stochastically. It is found that the tendency of the minimum variance and mean field directions to be aligned may be purely a consequence of the randomness of the field direction. In particular, a well-defined direction of minimum variance does not imply that the fluctuations are necessarily planar. The fluctuation power spectrum is a power law for frequencies much higher than the inverse of the correlation time. The probability distribution of directions a randomly fluctuating field of constant magnitude is calculated. A new approach for observational studies of interplanetary fluctuations is suggested

  12. Charge Fluctuations of an Uncharged Black Hole

    OpenAIRE

    Schiffer, Marcelo

    2016-01-01

    In this paper we calculate charge fluctuations of a Schwarzschild black-hole of mass $M$ confined within a perfectly reflecting cavity of radius R in thermal equilibrium with various species of radiation and fermions . Charge conservation is constrained by a Lagrange multiplier (the chemical potential). Black hole charge fluctuations are expected owing to continuous absorption and emission of particles by the black hole. For black holes much more massive than $10^{16} g$ , these fluctuations ...

  13. Wind fluctuations over the North Sea

    DEFF Research Database (Denmark)

    Vincent, Claire Louise; Pinson, Pierre; Giebel, Gregor

    2011-01-01

    Climatological patterns in wind speed fluctuations with periods of 1 min to 10 h are analysed using data from a meteorological mast in the Danish North Sea. Fluctuations on these time scales are of particular relevance to the effective management of the power supply from large wind farms. The Hil......Climatological patterns in wind speed fluctuations with periods of 1 min to 10 h are analysed using data from a meteorological mast in the Danish North Sea. Fluctuations on these time scales are of particular relevance to the effective management of the power supply from large wind farms...

  14. Neutrino propagation in a fluctuating sun

    International Nuclear Information System (INIS)

    Burgess, C.P.; Michaud, D.

    1997-01-01

    We adapt to neutrino physics a general formulation for particle propagation in fluctuating media, initially developed for applications to electromagnetism and neutron optics. In leading approximation this formalism leads to the usual MSW effective Hamiltonian governing neutrino propagation through a medium. Next-to-leading contributions describe deviations from this description, which arise due to neutrino interactions with fluctuations in the medium. We compute these corrections for two types of fluctuations: (i) microscopic thermal fluctuations and (ii) macroscopic fluctuations in the medium s density. While the first of these reproduces standard estimates, which are negligible for applications to solar neutrinos, we find that the second can be quite large, since it grows in size with the correlation length of the fluctuation. We consider two models in some detail. For fluctuations whose correlations extend only over a local region in space of length l, appreciable effects for MSW oscillations arise if (δn/n) 2 l approx-gt 100m or so. Alternatively, a crude model of helioseismic p-waves gives appreciable effects only when (δn/n)approx-gt 1%. In general the dominant effect is to diminish the quality of the resonance, making the suppression of the 7 Be neutrinos a good experimental probe of fluctuations deep within the sun. Fluctuations can also provide a new mechanism for reducing the solar neutrino flux, giving an energy-independent suppression factor of 1/2 away from the resonant region, even for small vacuum mixing angles. copyright 1997 Academic Press, Inc

  15. Non-Gaussian conductivity fluctuations in semiconductors

    International Nuclear Information System (INIS)

    Melkonyan, S.V.

    2010-01-01

    A theoretical study is presented on the statistical properties of conductivity fluctuations caused by concentration and mobility fluctuations of the current carriers. It is established that mobility fluctuations result from random deviations in the thermal equilibrium distribution of the carriers. It is shown that mobility fluctuations have generation-recombination and shot components which do not satisfy the requirements of the central limit theorem, in contrast to the current carrier's concentration fluctuation and intraband component of the mobility fluctuation. It is shown that in general the mobility fluctuation consist of thermal (or intraband) Gaussian and non-thermal (or generation-recombination, shot, etc.) non-Gaussian components. The analyses of theoretical results and experimental data from literature show that the statistical properties of mobility fluctuation and of 1/f-noise fully coincide. The deviation from Gaussian statistics of the mobility or 1/f fluctuations goes hand in hand with the magnitude of non-thermal noise (generation-recombination, shot, burst, pulse noises, etc.).

  16. Development of fluctuation monitor type sodium ionization detector

    International Nuclear Information System (INIS)

    Yamamoto, Hajime; Sato, Yoshihiko; Ibe, Eishi; Suzuoki, Akira

    1986-01-01

    In order to improve the sensitivity and the reliability of the sodium leak detection system used in the fast breeder reactors, a new type SID (sodium ionization detector) has been developed, in which the monitored signal is only the fluctuating component of the current between the filament and the ion collector. The fluctuating component was extracted by a band pass filter and its root mean square value was calculated as the SID signal. Fluctuation characteristics of the output current were studied by its frequency spectrum. The results revealed that the current spectrum was affected by the particle size distribution of the aerosol and was most clearly distinguished from that of the background current in the frequency region of 0.5 ∼ 10 Hz. Output characteristics of the fluctuation monitor type SID (FM-SID) were obtained as a function of sodium concentration in the gas. The FM-SID sensitivity was lowered by impurities in the gas, such as oxygen and water vapor. Finally, in comparisons with the conventional DC-SIDs, the background noise level of the FM-SID was much lower and S/N ratio was greatly improved. The detectable sodium concentration level was ten times lower than that of the DC-SID. (author)

  17. Fluctuations in work motivation: tasks do not matter!

    Science.gov (United States)

    Navarro, Jose; Curioso, Fernando; Gomes, Duarte; Arrieta, Carlos; Cortes, Mauricio

    2013-01-01

    Previous studies have shown that work motivation fluctuates considerably and in a nonlinear way over time. In the present research, we are interested in studying if the task at hand does or does not influence the presence of these fluctuations. We gathered daily registers from 69 workers during 21 consecutive working days (7036 registers) of task developed and levels of motivation, self-efficacy beliefs and instrumentalities perception. These registers were then categorized into a list of labor activities in main tasks and subtasks by means of three judges with a high level of agreement (97.47% for tasks, and 98.64% for subtasks). Taking the MSSD statistic (mean squared successive difference) of the average of motivation, self-efficacy and instrumentality, and using hierarchical regression analysis we have found that tasks (beta = .03; p = .188) and subtasks (beta = .10; p = .268) do not affect the presence of fluctuations in motivation. These results reveal instability in work motivation independently from the tasks and subtasks that the workers do. We proceed to find that fluctuations in work motivation show a fractal structure across the different tasks we do in a working day. Implications of these results to motivational theory will be discussed as well as possible explanations (e.g. the influence of affect in work motivation) and directions for future research are provided.

  18. Tunnel flexibility effect on the ground surface acceleration response

    Science.gov (United States)

    Baziar, Mohammad Hassan; Moghadam, Masoud Rabeti; Choo, Yun Wook; Kim, Dong-Soo

    2016-09-01

    Flexibility of underground structures relative to the surrounding medium, referred to as the flexibility ratio, is an important factor that influences their dynamic interaction. This study investigates the flexibility effect of a box-shaped subway tunnel, resting directly on bedrock, on the ground surface acceleration response using a numerical model verified against dynamic centrifuge test results. A comparison of the ground surface acceleration response for tunnel models with different flexibility ratios revealed that the tunnels with different flexibility ratios influence the acceleration response at the ground surface in different ways. Tunnels with lower flexibility ratios have higher acceleration responses at short periods, whereas tunnels with higher flexibility ratios have higher acceleration responses at longer periods. The effect of the flexibility ratio on ground surface acceleration is more prominent in the high range of frequencies. Furthermore, as the flexibility ratio of the tunnel system increases, the acceleration response moves away from the free field response and shifts towards the longer periods. Therefore, the flexibility ratio of the underground tunnels influences the peak ground acceleration (PGA) at the ground surface, and may need to be considered in the seismic zonation of urban areas.

  19. Energy Flexibility in Retail Buildings

    DEFF Research Database (Denmark)

    Ma, Zheng; Billanes, Joy Dalmacio; Kjærgaard, Mikkel Baun

    2017-01-01

    Retail buildings has an important role for demand side energy flexibility because of their high energy consumption, variety of energy flexibility resources, and centralized control via building control systems. Energy flexibility requires agreements and collaborations among different actors......), with the discussion of the stakeholders’ roles and their interrelation in delivering energy flexibility with the influential factors to the actual implementation of energy flexible operation of their buildings. Based on a literature analysis, the results cover stakeholders’ types and roles, perceptions (drivers......, barriers, and benefits), energy management activities and technology adoptions, and the stakeholders’ interaction for the energy flexibility in retail buildings....

  20. Multiscale weighted colored graphs for protein flexibility and rigidity analysis

    Science.gov (United States)

    Bramer, David; Wei, Guo-Wei

    2018-02-01

    Protein structural fluctuation, measured by Debye-Waller factors or B-factors, is known to correlate to protein flexibility and function. A variety of methods has been developed for protein Debye-Waller factor prediction and related applications to domain separation, docking pose ranking, entropy calculation, hinge detection, stability analysis, etc. Nevertheless, none of the current methodologies are able to deliver an accuracy of 0.7 in terms of the Pearson correlation coefficients averaged over a large set of proteins. In this work, we introduce a paradigm-shifting geometric graph model, multiscale weighted colored graph (MWCG), to provide a new generation of computational algorithms to significantly change the current status of protein structural fluctuation analysis. Our MWCG model divides a protein graph into multiple subgraphs based on interaction types between graph nodes and represents the protein rigidity by generalized centralities of subgraphs. MWCGs not only predict the B-factors of protein residues but also accurately analyze the flexibility of all atoms in a protein. The MWCG model is validated over a number of protein test sets and compared with many standard methods. An extensive numerical study indicates that the proposed MWCG offers an accuracy of over 0.8 and thus provides perhaps the first reliable method for estimating protein flexibility and B-factors. It also simultaneously predicts all-atom flexibility in a molecule.

  1. Recent results on event-by-event fluctuations in ALICE at the LHC

    CERN Document Server

    AUTHOR|(CDS)2083375

    2015-01-01

    Non-statistical event-by-event fluctuations in relativistic heavy-ion collisions have been proposed as a probe of the phase transition of hadronic matter to a deconfined phase of quarks and gluons, the so-called Quark-Gluon Plasma. In a thermodynamical picture of the strongly interacting system formed in heavy-ion collisions, the dynamical fluctuations of net-charge, fluctuations of the mean transverse momentum, mean multiplicity and balance functions are related to the fundamental properties of the system, hence they may reveal information about the QCD phase transition. In this article, recent results on event-by-event measurements of net-charge fluctuations, the measurement of the balance function and mean transverse momentum fluctuations are discussed.

  2. LABOUR MARKET FLEXIBILITY IN TERMS OF INTERNAL MIGRATION

    Directory of Open Access Journals (Sweden)

    BUNEA DANIELA

    2010-07-01

    Full Text Available Modern economies have a high dynamics because of the rapid fluctuations of macroeconomic variables and parameters. Moreover, globalization emphasises the interdependencies among national economies, increasing their production capacities but, at the same time, making them more vulnerable to external perturbations. Shocks resulting from this turmoil can be absorbed depending on the degree of macromarket flexibility: goods market, labour market and money market. This flexibility becomes even more important for the member states of some optimal currency areas (OCA because it considers both the mobility of production factors and the symmetry of business cycle transmission; i.e. the correlation of macroeconomic policies. The authors of this paper intend to analyse the situation of the internal mobility of workers as a basis for labour market flexibility.

  3. Diffusion in flexible pipes

    Energy Technology Data Exchange (ETDEWEB)

    Brogaard Kristensen, S.

    2000-06-01

    This report describes the work done on modelling and simulation of the complex diffusion of gas through the wall of a flexible pipe. The diffusion and thus the pressure in annulus depends strongly on the diffusion and solubility parameters of the gas-polymer system and on the degree of blocking of the outer surface of the inner liner due to pressure reinforcements. The report evaluates the basis modelling required to describe the complex geometries and flow patterns. Qualitatively results of temperature and concentration profiles are shown in the report. For the program to serve any modelling purpose in 'real life' the results need to be validated and possibly the model needs corrections. Hopefully, a full-scale test of a flexible pipe will provide the required temperatures and pressures in annulus to validate the models. (EHS)

  4. Flexible cryogenic conduit

    International Nuclear Information System (INIS)

    Brindza, P.D.; Wines, R.R.; Takacs, J.J.

    1999-01-01

    A flexible and relatively low cost cryogenic conduit is described. The flexible cryogenic conduit of the present invention comprises a first inner corrugated tube with single braided serving, a second outer corrugated tube with single braided serving concentric with the inner corrugated tube, and arranged outwardly about the periphery of the inner corrugated tube and between the inner and outer corrugated tubes: a superinsulation layer; a one half lap layer of polyester ribbon; a one half lap layer of copper ribbon; a spirally wound refrigeration tube; a second one half lap layer of copper ribbon; a second one half lap layer of polyester ribbon; a second superinsulation layer; a third one half lap layer of polyester ribbon; and a spirally wound stretchable and compressible filament

  5. Diffusion in flexible pipes

    Energy Technology Data Exchange (ETDEWEB)

    Brogaard Kristensen, S

    2000-06-01

    This report describes the work done on modelling and simulation of the complex diffusion of gas through the wall of a flexible pipe. The diffusion and thus the pressure in annulus depends strongly on the diffusion and solubility parameters of the gas-polymer system and on the degree of blocking of the outer surface of the inner liner due to pressure reinforcements. The report evaluates the basis modelling required to describe the complex geometries and flow patterns. Qualitatively results of temperature and concentration profiles are shown in the report. For the program to serve any modelling purpose in 'real life' the results need to be validated and possibly the model needs corrections. Hopefully, a full-scale test of a flexible pipe will provide the required temperatures and pressures in annulus to validate the models. (EHS)

  6. Flexible Laser Metal Cutting

    DEFF Research Database (Denmark)

    Villumsen, Sigurd; Jørgensen, Steffen Nordahl; Kristiansen, Morten

    2014-01-01

    This paper describes a new flexible and fast approach to laser cutting called ROBOCUT. Combined with CAD/CAM technology, laser cutting of metal provides the flexibility to perform one-of-a-kind cutting and hereby realises mass production of customised products. Today’s laser cutting techniques...... possess, despite their wide use in industry, limitations regarding speed and geometry. Research trends point towards remote laser cutting techniques which can improve speed and geometrical freedom and hereby the competitiveness of laser cutting compared to fixed-tool-based cutting technology...... such as punching. This paper presents the concepts and preliminary test results of the ROBOCUT laser cutting technology, a technology which potentially can revolutionise laser cutting....

  7. Flexible training under threat.

    Science.gov (United States)

    Houghton, Anita; Eaton, Jennifer

    2002-10-01

    As the number of women in medicine and the general demand for a better work-life balance rises, flexible training is an increasingly important mechanism for maintaining the medical workforce. The new pay deal, together with entrenched cultural attitudes, are potential threats. Ways forward include more substantive part-time posts, more part-time opportunities at consultant level, and using positive experiences as a way of tackling attitudes in the less accepting specialties.

  8. Flexible weapons architecture design

    OpenAIRE

    Pyant, William C.

    2015-01-01

    Present day air-delivered weapons are of a closed architecture, with little to no ability to tailor the weapon for the individual engagement. The closed architectures require weaponeers to make the target fit the weapon instead of fitting the individual weapons to a target. The concept of a flexible weapons aims to modularize weapons design using an open architecture shell into which different modules are inserted to achieve the desired target fractional damage while reducing cost and civilia...

  9. Industrial Fuel Flexibility Workshop

    Energy Technology Data Exchange (ETDEWEB)

    none,

    2006-09-01

    On September 28, 2006, in Washington, DC, ITP and Booz Allen Hamilton conducted a fuel flexibility workshop with attendance from various stakeholder groups. Workshop participants included representatives from the petrochemical, refining, food and beverage, steel and metals, pulp and paper, cement and glass manufacturing industries; as well as representatives from industrial boiler manufacturers, technology providers, energy and waste service providers, the federal government and national laboratories, and developers and financiers.

  10. Flexible Land Administration

    DEFF Research Database (Denmark)

    Enemark, Stig

    2014-01-01

    Security of tenure is widely considered to be the missing piece of the puzzle when it comes to eradication of poverty. And, as explained in the previous issue of Geoinformatics, the European Union is now placing land rights at the heart of EU development policy. This article presents a way forwar...... in terms of building flexible and "fit-for-purpose" land administration systems in developing countries. This will ensure security of tenure for all and sustainable management of the use of land....

  11. Modeling of fluctuating reaction networks

    International Nuclear Information System (INIS)

    Lipshtat, A.; Biham, O.

    2004-01-01

    Full Text:Various dynamical systems are organized as reaction networks, where the population size of one component affects the populations of all its neighbors. Such networks can be found in interstellar surface chemistry, cell biology, thin film growth and other systems. I cases where the populations of reactive species are large, the network can be modeled by rate equations which provide all reaction rates within mean field approximation. However, in small systems that are partitioned into sub-micron size, these populations strongly fluctuate. Under these conditions rate equations fail and the master equation is needed for modeling these reactions. However, the number of equations in the master equation grows exponentially with the number of reactive species, severely limiting its feasibility for complex networks. Here we present a method which dramatically reduces the number of equations, thus enabling the incorporation of the master equation in complex reaction networks. The method is examplified in the context of reaction network on dust grains. Its applicability for genetic networks will be discussed. 1. Efficient simulations of gas-grain chemistry in interstellar clouds. Azi Lipshtat and Ofer Biham, Phys. Rev. Lett. 93 (2004), 170601. 2. Modeling of negative autoregulated genetic networks in single cells. Azi Lipshtat, Hagai B. Perets, Nathalie Q. Balaban and Ofer Biham, Gene: evolutionary genomics (2004), In press

  12. PTFE films with improved flexibility

    Science.gov (United States)

    Muraca, R. F.; Koch, A. A.

    1972-01-01

    Development and application of flexible polytetrafluroethylene films for expulsion bladders in spacecraft propellant tanks are described. Flexibility of material is obtained by reducing crystallinity through annealing and quenching in water. Physical and mechanical properties of material are presented.

  13. Thermal turbulent convection: thermal plumes and fluctuations

    International Nuclear Information System (INIS)

    Gibert, M.

    2007-10-01

    In this study we investigate the phenomenon of thermal turbulent convection in new and unprecedented ways. The first system we studied experimentally is an infinite vertical channel, where a constant vertical mean gradient of temperature exists. Inside this channel the average mass flux is null. The results obtained from our measurements reveal that the flow is mainly inertial; indeed the dissipative coefficients (here the viscosity) play a role only to define a coherence length L. This length is the distance over which the thermal plumes can be considered as 'free falling' objects. The horizontal transport, of heat and momentum, is entirely due to fluctuations. The associated 'mixing length' is small compared to the channel width. In the other hand, the vertical heat transport is due to coherent structures: the heat plumes. Those objects were also investigated in a Lagrangian study of the flow in the bulk of a Rayleigh-Benard cell. The probe, which has the same density as the fluid used in this experiment, is a sphere of 2 cm in diameter with embarked thermometers and radio-emitter. The heat plumes transport it, which allows a statistical study of such objects. (author)

  14. Measuring shape fluctuations in biological membranes

    International Nuclear Information System (INIS)

    Monzel, C; Sengupta, K

    2016-01-01

    Shape fluctuations of lipid membranes have intrigued cell biologists and physicists alike. In the cellular context, their origin—thermal or active—and their physiological significance are open questions. These small incessant displacements, also called membrane undulations, have mostly been studied in model membranes and membranes of simple cells like erythrocytes. Thermal fluctuations of such membranes have been very well described both theoretically and experimentally; active fluctuations are a topic of current interest. Experimentally, membrane fluctuations are not easy to measure, the main challenge being to develop techniques which are capable of measuring very small displacements at very high speed, and preferably over a large area and long time. Scattering techniques have given access to fluctuations in membrane stacks and a variety of optical microscopy based techniques have been devised to study membrane fluctuations of unilamellar vesicles, erythrocytes and other cells. Among them are flicker spectroscopy, dynamic light scattering, diffraction phase microscopy and reflection interference contrast microscopy. Each of these techniques has its advantages and limitations. Here we review the basic principles of the major experimental techniques used to measure bending or shape fluctuations of biomembranes. We report seminal results obtained with each technique and highlight how these studies furthered our understanding of physical properties of membranes and their interactions. We also discuss suggested role of membrane fluctuations in different biological processes. (topical review)

  15. The Spectrum of Wind Power Fluctuations

    Science.gov (United States)

    Bandi, Mahesh

    2016-11-01

    Wind is a variable energy source whose fluctuations threaten electrical grid stability and complicate dynamical load balancing. The power generated by a wind turbine fluctuates due to the variable wind speed that blows past the turbine. Indeed, the spectrum of wind power fluctuations is widely believed to reflect the Kolmogorov spectrum; both vary with frequency f as f - 5 / 3. This variability decreases when aggregate power fluctuations from geographically distributed wind farms are averaged at the grid via a mechanism known as geographic smoothing. Neither the f - 5 / 3 wind power fluctuation spectrum nor the mechanism of geographic smoothing are understood. In this work, we explain the wind power fluctuation spectrum from the turbine through grid scales. The f - 5 / 3 wind power fluctuation spectrum results from the largest length scales of atmospheric turbulence of order 200 km influencing the small scales where individual turbines operate. This long-range influence spatially couples geographically distributed wind farms and synchronizes farm outputs over a range of frequencies and decreases with increasing inter-farm distance. Consequently, aggregate grid-scale power fluctuations remain correlated, and are smoothed until they reach a limiting f - 7 / 3 spectrum. This work was funded by the Collective Interactions Unit, OIST Graduate University, Japan.

  16. Intrinsic intensity fluctuations in random lasers

    International Nuclear Information System (INIS)

    Molen, Karen L. van der; Mosk, Allard P.; Lagendijk, Ad

    2006-01-01

    We present a quantitative experimental and theoretical study of intensity fluctuations in the emitted light of a random laser that has different realizations of disorder for every pump pulse. A model that clarifies these intrinsic fluctuations is developed. We describe the output versus input power graphs of the random laser with an effective spontaneous emission factor (β factor)

  17. Fluctuations of offshore wind generation: Statistical modelling

    DEFF Research Database (Denmark)

    Pinson, Pierre; Christensen, Lasse E.A.; Madsen, Henrik

    2007-01-01

    The magnitude of power fluctuations at large offshore wind farms has a significant impact on the control and management strategies of their power output. If focusing on the minute scale, one observes successive periods with smaller and larger power fluctuations. It seems that different regimes yi...

  18. Multi moment cancellation of participant fluctuations

    OpenAIRE

    Begun, Viktor; Mackowiak-Pawlowska, Maja

    2017-01-01

    We summarize the new method for the correction of participant fluctuations in high energy nucleus-nucleus collisions. It allows to estimate a fluctuation baseline in comparison to a useful signal. In particular cases of a weak signal compared to baseline, it allows to cancel the baseline contribution from participants.

  19. Flexible automated manufacturing for SMEs

    DEFF Research Database (Denmark)

    Grube Hansen, David; Bilberg, Arne; Madsen, Erik Skov

    2017-01-01

    SMEs are in general highly flexible and agile in order to accommodate the customer demands in the paradigm of High Mix-Low Volume manufacturing. The flexibility and agility have mainly been enabled by manual labor, but as we are entering the technology and data driven fourth industrial revolution......, where augmented operators and machines work in cooperation in a highly flexible and productive manufacturing system both an opportunity and a need has raised for developing highly flexible and efficient automation....

  20. Short-term fluctuations in motivation to quit smoking in a sample of smokers in Hawaii.

    Science.gov (United States)

    Herzog, Thaddeus; Pokhrel, Pallav; Kawamoto, Crissy T

    2015-01-01

    Despite its potential for usefulness in informing the development of smoking cessation interventions, short-term fluctuations in motivation to quit is a relatively understudied topic. To assess the prevalence of smokers' day-to-day fluctuations in motivation to quit, and to assess associations of day-to-day fluctuations in motivation to quit with several established cessation-related variables. A cross-sectional survey was administered to smokers in Hawaii (N = 1,567). To assess short-term fluctuations in motivation to quit smoking, participants were asked to respond "True" or "False" to the statement: "My motivation to quit smoking changes from one day to the next." Other items measured desire to quit smoking, intention to quit, confidence in quitting, cigarette dependence, and other cessation-related variables. "My motivation to quit smoking changes from one day to the next" was endorsed as true by 64.7% of smokers, and false by 35.3%. Analyses revealed that smokers who indicated fluctuating motivation were significantly more interested in quitting as compared to smokers without fluctuations. Fluctuations in motivation to quit also were associated with greater confidence in quitting, lesser cigarette dependence, and more recent quitting activity (all p motivation to quit are common. Day-to-day fluctuations in motivation to quit are strongly associated with higher motivation to quit, greater confidence in future quitting, and other positive cessation-relevant trends.

  1. Control voltage and power fluctuations when connecting wind farms

    Science.gov (United States)

    Berinde, Ioan; Bǎlan, Horia; Oros Pop, Teodora Susana

    2015-12-01

    Voltage, frequency, active power and reactive power are very important parameters in terms of power quality. These parameters are followed when connecting any power plant, the more the connection of wind farms. Connecting wind farms to the electricity system must not cause interference outside the limits set by regulations. Modern solutions for fast and automatic voltage control and power fluctuations using electronic control systems of reactive power flows. FACTS (Flexible Alternating Current Transmision System) systems, established on the basis of power electronic circuits ensure control of electrical status quantities to achieve the necessary transfer of power to the power grid. FACTS devices can quickly control parameters and sizes of state power lines, such as impedance line voltages and phase angles of the voltages of the two ends of the line. Their use can lead to improvement in power system operation by increasing the transmission capacity of power lines, power flow control lines, improved static and transient stability reserve.

  2. Control voltage and power fluctuations when connecting wind farms

    International Nuclear Information System (INIS)

    Berinde, Ioan; Bălan, Horia; Oros, Teodora Susana

    2015-01-01

    Voltage, frequency, active power and reactive power are very important parameters in terms of power quality. These parameters are followed when connecting any power plant, the more the connection of wind farms. Connecting wind farms to the electricity system must not cause interference outside the limits set by regulations. Modern solutions for fast and automatic voltage control and power fluctuations using electronic control systems of reactive power flows. FACTS (Flexible Alternating Current Transmision System) systems, established on the basis of power electronic circuits ensure control of electrical status quantities to achieve the necessary transfer of power to the power grid. FACTS devices can quickly control parameters and sizes of state power lines, such as impedance line voltages and phase angles of the voltages of the two ends of the line. Their use can lead to improvement in power system operation by increasing the transmission capacity of power lines, power flow control lines, improved static and transient stability reserve

  3. Control voltage and power fluctuations when connecting wind farms

    Energy Technology Data Exchange (ETDEWEB)

    Berinde, Ioan, E-mail: ioan-berinde@yahoo.com; Bălan, Horia, E-mail: hbalan@mail.utcluj.ro; Oros, Teodora Susana, E-mail: teodoraoros-87@yahoo.com [Technical University of Cluj-Napoca, Romania, Faculty of Electrical Engineering, Department of Power Engineering and Management (Romania)

    2015-12-23

    Voltage, frequency, active power and reactive power are very important parameters in terms of power quality. These parameters are followed when connecting any power plant, the more the connection of wind farms. Connecting wind farms to the electricity system must not cause interference outside the limits set by regulations. Modern solutions for fast and automatic voltage control and power fluctuations using electronic control systems of reactive power flows. FACTS (Flexible Alternating Current Transmision System) systems, established on the basis of power electronic circuits ensure control of electrical status quantities to achieve the necessary transfer of power to the power grid. FACTS devices can quickly control parameters and sizes of state power lines, such as impedance line voltages and phase angles of the voltages of the two ends of the line. Their use can lead to improvement in power system operation by increasing the transmission capacity of power lines, power flow control lines, improved static and transient stability reserve.

  4. Coupled Quantum Fluctuations and Quantum Annealing

    Science.gov (United States)

    Hormozi, Layla; Kerman, Jamie

    We study the relative effectiveness of coupled quantum fluctuations, compared to single spin fluctuations, in the performance of quantum annealing. We focus on problem Hamiltonians resembling the the Sherrington-Kirkpatrick model of Ising spin glass and compare the effectiveness of different types of fluctuations by numerically calculating the relative success probabilities and residual energies in fully-connected spin systems. We find that for a small class of instances coupled fluctuations can provide improvement over single spin fluctuations and analyze the properties of the corresponding class. Disclaimer: This research was funded by ODNI, IARPA via MIT Lincoln Laboratory under Air Force Contract No. FA8721-05-C-0002. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of ODNI, IARPA, or the US Government.

  5. Designing structural supply chain flexibility

    NARCIS (Netherlands)

    Mulinski, Ksawery Jan

    2012-01-01

    In a continuously changing business environment the role of supply chain flexibility is constantly increasing. A flexible supply chain can ensure survival in quickly changing market conditions as well as enable sustainable growth. This thesis explores the topic of supply chain flexibility with focus

  6. Global Analysis of Flexible Risers

    DEFF Research Database (Denmark)

    Banke, Lars

    1996-01-01

    Flexible pipes are often a technically attractive alternative to the traditional steel pipe. Often commercial utilisation of oil/gas fields depends on the use of flexible pipes. An example is when floating production vessels are used, where the flexible pipe follows the wave induced motions...

  7. Stability and fluctuations in black hole thermodynamics

    International Nuclear Information System (INIS)

    Ruppeiner, George

    2007-01-01

    I examine thermodynamic fluctuations for a Kerr-Newman black hole in an extensive, infinite environment. This problem is not strictly solvable because full equilibrium with such an environment cannot be achieved by any black hole with mass M, angular momentum J, and charge Q. However, if we consider one (or two) of M, J, or Q to vary so slowly compared with the others that we can regard it as fixed, instances of stability occur, and thermodynamic fluctuation theory could plausibly apply. I examine seven cases with one, two, or three independent fluctuating variables. No knowledge about the thermodynamic behavior of the environment is needed. The thermodynamics of the black hole is sufficient. Let the fluctuation moment for a thermodynamic quantity X be √( 2 >). Fluctuations at fixed M are stable for all thermodynamic states, including that of a nonrotating and uncharged environment, corresponding to average values J=Q=0. Here, the fluctuation moments for J and Q take on maximum values. That for J is proportional to M. For the Planck mass it is 0.3990(ℎ/2π). That for Q is 3.301e, independent of M. In all cases, fluctuation moments for M, J, and Q go to zero at the limit of the physical regime, where the temperature goes to zero. With M fluctuating there are no stable cases for average J=Q=0. But, there are transitions to stability marked by infinite fluctuations. For purely M fluctuations, this coincides with a curve which Davies identified as a phase transition

  8. RF current drive and plasma fluctuations

    International Nuclear Information System (INIS)

    Peysson, Yves; Decker, Joan; Morini, L; Coda, S

    2011-01-01

    The role played by electron density fluctuations near the plasma edge on rf current drive in tokamaks is assessed quantitatively. For this purpose, a general framework for incorporating density fluctuations in existing modelling tools has been developed. It is valid when rf power absorption takes place far from the fluctuating region of the plasma. The ray-tracing formalism is modified in order to take into account time-dependent perturbations of the density, while the Fokker–Planck solver remains unchanged. The evolution of the electron distribution function in time and space under the competing effects of collisions and quasilinear diffusion by rf waves is determined consistently with the time scale of fluctuations described as a statistical process. Using the ray-tracing code C3PO and the 3D linearized relativistic bounce-averaged Fokker–Planck solver LUKE, the effect of electron density fluctuations on the current driven by the lower hybrid (LH) and the electron cyclotron (EC) waves is estimated quantitatively. A thin fluctuating layer characterized by electron drift wave turbulence at the plasma edge is considered. The effect of fluctuations on the LH wave propagation is equivalent to a random scattering process with a broadening of the poloidal mode spectrum proportional to the level of the perturbation. However, in the multipass regime, the LH current density profile remains sensitive to the ray chaotic behaviour, which is not averaged by fluctuations. The effect of large amplitude fluctuations on the EC driven current is found to be similar to an anomalous radial transport of the fast electrons. The resulting lower current drive efficiency and broader current profile are in better agreement with experimental observations. Finally, applied to the ITER ELMy H-mode regime, the model predicts a significant broadening of the EC driven current density profile with the fluctuation level, which can make the stabilization of neoclassical tearing mode potentially

  9. Plasma fluctuation measurements in tokamaks using beam-plasma interactions

    International Nuclear Information System (INIS)

    Fonck, R.J.; Duperrex, P.A.; Paul, S.F.

    1990-01-01

    High-frequency observations of light emitted from the interactions between plasma ions and injected neutral beam atoms allow the measurement of moderate-wavelength fluctuations in plasma and impurity ion densities. To detect turbulence in the local plasma ion density, the collisionally excited fluorescence from a neutral beam is measured either separately at several spatial points or with a multichannel imaging detector. Similarly, the role of impurity ion density fluctuations is measured using charge exchange recombination excited transitions emitted by the ion species of interest. This technique can access the relatively unexplored region of long-wavelength plasma turbulence with k perpendicular ρ i much-lt 1, and hence complements measurements from scattering experiments. Optimization of neutral beam geometry and optical sightlines can result in very good localization and resolution (Δx≤1 cm) in the hot plasma core region. The detectable fluctuation level is determined by photon statistics, atomic excitation processes, and beam stability, but can be as low as 0.2% in a 100 kHz bandwidth over the 0--1 MHz frequency range. The choices of beam species (e.g., H 0 , He 0 , etc.), observed transition (e.g., H α , L α , He I singlet or triplet transitions, C VI Δn=1, etc.) are dictated by experiment-specific factors such as optical access, flexibility of beam operation, plasma conditions, and detailed experimental goals. Initial tests on the PBX-M tokamak using the H α emissions from a heating neutral beam show low-frequency turbulence in the edge plasma region

  10. Conformational Fluctuations in G-Protein-Coupled Receptors

    Science.gov (United States)

    Brown, Michael F.

    2014-03-01

    G-protein-coupled receptors (GPCRs) comprise almost 50% of pharmaceutical drug targets, where rhodopsin is an important prototype and occurs naturally in a lipid membrane. Rhodopsin photoactivation entails 11-cis to all-trans isomerization of the retinal cofactor, yielding an equilibrium between inactive Meta-I and active Meta-II states. Two important questions are: (1) Is rhodopsin is a simple two-state switch? Or (2) does isomerization of retinal unlock an activated conformational ensemble? For an ensemble-based activation mechanism (EAM) a role for conformational fluctuations is clearly indicated. Solid-state NMR data together with theoretical molecular dynamics (MD) simulations detect increased local mobility of retinal after light activation. Resultant changes in local dynamics of the cofactor initiate large-scale fluctuations of transmembrane helices that expose recognition sites for the signal-transducing G-protein. Time-resolved FTIR studies and electronic spectroscopy further show the conformational ensemble is strongly biased by the membrane lipid composition, as well as pH and osmotic pressure. A new flexible surface model (FSM) describes how the curvature stress field of the membrane governs the energetics of active rhodopsin, due to the spontaneous monolayer curvature of the lipids. Furthermore, influences of osmotic pressure dictate that a large number of bulk water molecules are implicated in rhodopsin activation. Around 60 bulk water molecules activate rhodopsin, which is much larger than the number of structural waters seen in X-ray crystallography, or inferred from studies of bulk hydrostatic pressure. Conformational selection and promoting vibrational motions of rhodopsin lead to activation of the G-protein (transducin). Our biophysical data give a paradigm shift in understanding GPCR activation. The new view is: dynamics and conformational fluctuations involve an ensemble of substates that activate the cognate G-protein in the amplified visual

  11. Flexible Query Answering Systems

    DEFF Research Database (Denmark)

    This book constitutes the refereed proceedings of the 10th International Conference on Flexible Query Answering Systems, FQAS 2013, held in Granada, Spain, in September 2013. The 59 full papers included in this volume were carefully reviewed and selected from numerous submissions. The papers...... are organized in a general session train and a parallel special session track. The general session train covers the following topics: querying-answering systems; semantic technology; patterns and classification; personalization and recommender systems; searching and ranking; and Web and human...

  12. Fluctuating Asymmetry of Human Populations: A Review

    Directory of Open Access Journals (Sweden)

    John H. Graham

    2016-12-01

    Full Text Available Fluctuating asymmetry, the random deviation from perfect symmetry, is a widely used population-level index of developmental instability, developmental noise, and robustness. It reflects a population’s state of adaptation and genomic coadaptation. Here, we review the literature on fluctuating asymmetry of human populations. The most widely used bilateral traits include skeletal, dental, and facial dimensions; dermatoglyphic patterns and ridge counts; and facial shape. Each trait has its advantages and disadvantages, but results are most robust when multiple traits are combined into a composite index of fluctuating asymmetry (CFA. Both environmental (diet, climate, toxins and genetic (aneuploidy, heterozygosity, inbreeding stressors have been linked to population-level variation in fluctuating asymmetry. In general, these stressors increase average fluctuating asymmetry. Nevertheless, there have been many conflicting results, in part because (1 fluctuating asymmetry is a weak signal in a sea of noise; and (2 studies of human fluctuating asymmetry have not always followed best practices. The most serious concerns are insensitive asymmetry indices (correlation coefficient and coefficient of indetermination, inappropriate size scaling, unrecognized mixture distributions, inappropriate corrections for directional asymmetry, failure to use composite indices, and inattention to measurement error. Consequently, it is often difficult (or impossible to compare results across traits, and across studies.

  13. Fluctuations and structure of amphiphilic films

    International Nuclear Information System (INIS)

    Gourier, CH.

    1996-01-01

    This thesis is divided in three parts.The first part exposes in a theoretical point of view, how the fluctuations spectrum of an amphiphilic film is governed by its properties and its bidimensional characteristics.The measurements of fluctuations spectra of an interface are accessible with the measurement of intensity that interface diffuses out of the specular angle, we present in the second chapter the principles of the X rays diffusion by a real interface and see how the diffuse diffusion experiments allow to determine the fluctuations spectrum of an amphiphilic film. The second part is devoted to the different experimental techniques that have allowed to realize the study of fluctuation as well as the structural study.The third part is devoted to experimental results concerning the measurements of fluctuations spectra and to the study of the structure of amphiphilic films. We show that it is possible by using an intense source of X rays (ESRF: European Synchrotron Radiation Facility) to measure the water and amphiphilic films fluctuations spectra until molecular scales. The last chapter is devoted to the structural study and film fluctuations made of di-acetylenic molecules. (N.C.)

  14. Corporate Financial Flexibility, Investment Activities, and Cash Holding: Evidence From Indonesia

    OpenAIRE

    Rahmat Heru Setianto; Addenver Kusumaputra

    2017-01-01

    This paper examines empirically the impact of financial flexibility on investment activities. Furthermore, we also investigate how financial flexibility determines the sensitivity of investment activities to cash flow. Using annual data of Indonesian manufacturing firms spanning five years, our analyses reveal that financial flexibility enhances investment ability and decreases sensitivity of investment activities to cash flow. Further analysis indicates that financially flexible firms in Ind...

  15. Genomic insights into the Acidobacteria reveal strategies for their success in terrestrial environments

    Science.gov (United States)

    Trojan, Daniela; Roux, Simon; Herbold, Craig; Rattei, Thomas; Woebken, Dagmar

    2018-01-01

    Summary Members of the phylum Acidobacteria are abundant and ubiquitous across soils. We performed a large‐scale comparative genome analysis spanning subdivisions 1, 3, 4, 6, 8 and 23 (n = 24) with the goal to identify features to help explain their prevalence in soils and understand their ecophysiology. Our analysis revealed that bacteriophage integration events along with transposable and mobile elements influenced the structure and plasticity of these genomes. Low‐ and high‐affinity respiratory oxygen reductases were detected in multiple genomes, suggesting the capacity for growing across different oxygen gradients. Among many genomes, the capacity to use a diverse collection of carbohydrates, as well as inorganic and organic nitrogen sources (such as via extracellular peptidases), was detected – both advantageous traits in environments with fluctuating nutrient environments. We also identified multiple soil acidobacteria with the potential to scavenge atmospheric concentrations of H2, now encompassing mesophilic soil strains within the subdivision 1 and 3, in addition to a previously identified thermophilic strain in subdivision 4. This large‐scale acidobacteria genome analysis reveal traits that provide genomic, physiological and metabolic versatility, presumably allowing flexibility and versatility in the challenging and fluctuating soil environment. PMID:29327410

  16. Analysis of fluctuations in semiconductor devices

    Science.gov (United States)

    Andrei, Petru

    The random nature of ion implantation and diffusion processes as well as inevitable tolerances in fabrication result in random fluctuations of doping concentrations and oxide thickness in semiconductor devices. These fluctuations are especially pronounced in ultrasmall (nanoscale) semiconductor devices when the spatial scale of doping and oxide thickness variations become comparable with the geometric dimensions of devices. In the dissertation, the effects of these fluctuations on device characteristics are analyzed by using a new technique for the analysis of random doping and oxide thickness induced fluctuations. This technique is universal in nature in the sense that it is applicable to any transport model (drift-diffusion, semiclassical transport, quantum transport etc.) and it can be naturally extended to take into account random fluctuations of the oxide (trapped) charges and channel length. The technique is based on linearization of the transport equations with respect to the fluctuating quantities. It is computationally much (a few orders of magnitude) more efficient than the traditional Monte-Carlo approach and it yields information on the sensitivity of fluctuations of parameters of interest (e.g. threshold voltage, small-signal parameters, cut-off frequencies, etc.) to the locations of doping and oxide thickness fluctuations. For this reason, it can be very instrumental in the design of fluctuation-resistant structures of semiconductor devices. Quantum mechanical effects are taken into account by using the density-gradient model as well as through self-consistent Poisson-Schrodinger computations. Special attention is paid to the presenting of the technique in a form that is suitable for implementation on commercial device simulators. The numerical implementation of the technique is discussed in detail and numerous computational results are presented and compared with those previously published in literature.

  17. Computer simulations of phospholipid - membrane thermodynamic fluctuations

    DEFF Research Database (Denmark)

    Pedersen, U.R.; Peters, Günther H.j.; Schröder, T.B.

    2008-01-01

    This paper reports all-atom computer simulations of five phospholipid membranes, DMPC, DPPC, DMPG, DMPS, and DMPSH, with a focus on the thermal equilibrium fluctuations of volume, energy, area, thickness, and order parameter. For the slow fluctuations at constant temperature and pressure (defined...... membranes, showing a similar picture. The cause of the observed strong correlations is identified by splitting volume and energy into contributions from tails, heads, and water, showing that the slow volume-energy fluctuations derive from the tail region’s van der Waals interactions and are thus analogous...

  18. Charge-imbalance fluctuations in superconductors

    International Nuclear Information System (INIS)

    Lemberger, T.R.

    1981-01-01

    We calculate that the mean-square amplitude of the fluctuations of the condensate chemical potential μ/sub s/ due to charge-imbalance fluctuations in the limit Δ/k/sub B/T 2 > = 2(k/sub B/T) 2 /πdeltaΩN(0) in a volume Ω of superconductor. We relate these fluctuations via Nyquist's theorem to measured values of the contribution of self-injected charge imbalance to the dc resistance of SIN tunnel junctions. In this relation the dynamic charge-imbalance relaxation rate is 1/tau/sub E/, the electron-phonon scattering rate

  19. Fluctuations and transport in an inhomogeneous plasma

    International Nuclear Information System (INIS)

    Nevins, W.M.; Chen, L.

    1979-11-01

    A formalism is developed for calculating the equilibrium fluctuation level in an inhomogeneous plasma. This formalism is applied to the collisionless drift wave in a sheared magnetic field. The fluctuation level is found to be anomalously large due to both the presence of weakly damped normal modes and convective amplification. As the magnetic shear is reduced, the steady-state fluctuation spectrum is found to increase both in coherence and in amplitude. The transport associated with this mode is evaluated. The diffusion coefficient is found to scale as D is proportional to B 2 /nT/sup 1/2/

  20. Pairing fluctuations in trapped Fermi gases

    International Nuclear Information System (INIS)

    Viverit, Luciano; Bruun, Georg M.; Minguzzi, Anna; Fazio, Rosario

    2004-01-01

    We examine the contribution of pairing fluctuations to the superfluid order parameter for harmonically trapped atomic Fermi gases in the BCS regime. In the limit of small systems we consider, both analytically and numerically, their space and temperature dependence. We predict a parity effect, i.e., that pairing fluctuations show a maximum or a minimum at the center of the trap, depending on the value of the last occupied shell being even or odd. We propose to detect pairing fluctuations by measuring the density-density correlation function after a ballistic expansion of the gas

  1. Equilibrium & Nonequilibrium Fluctuation Effects in Biopolymer Networks

    Science.gov (United States)

    Kachan, Devin Michael

    Fluctuation-induced interactions are an important organizing principle in a variety of soft matter systems. In this dissertation, I explore the role of both thermal and active fluctuations within cross-linked polymer networks. The systems I study are in large part inspired by the amazing physics found within the cytoskeleton of eukaryotic cells. I first predict and verify the existence of a thermal Casimir force between cross-linkers bound to a semi-flexible polymer. The calculation is complicated by the appearance of second order derivatives in the bending Hamiltonian for such polymers, which requires a careful evaluation of the the path integral formulation of the partition function in order to arrive at the physically correct continuum limit and properly address ultraviolet divergences. I find that cross linkers interact along a filament with an attractive logarithmic potential proportional to thermal energy. The proportionality constant depends on whether and how the cross linkers constrain the relative angle between the two filaments to which they are bound. The interaction has important implications for the synthesis of biopolymer bundles within cells. I model the cross-linkers as existing in two phases: bound to the bundle and free in solution. When the cross-linkers are bound, they behave as a one-dimensional gas of particles interacting with the Casimir force, while the free phase is a simple ideal gas. Demanding equilibrium between the two phases, I find a discontinuous transition between a sparsely and a densely bound bundle. This discontinuous condensation transition induced by the long-ranged nature of the Casimir interaction allows for a similarly abrupt structural transition in semiflexible filament networks between a low cross linker density isotropic phase and a higher cross link density bundle network. This work is supported by the results of finite element Brownian dynamics simulations of semiflexible filaments and transient cross-linkers. I

  2. Asymmetric Flexible Supercapacitor Stack

    Directory of Open Access Journals (Sweden)

    Leela Mohana Reddy A

    2008-01-01

    Full Text Available AbstractElectrical double layer supercapacitor is very significant in the field of electrical energy storage which can be the solution for the current revolution in the electronic devices like mobile phones, camera flashes which needs flexible and miniaturized energy storage device with all non-aqueous components. The multiwalled carbon nanotubes (MWNTs have been synthesized by catalytic chemical vapor deposition technique over hydrogen decrepitated Mischmetal (Mm based AB3alloy hydride. The polymer dispersed MWNTs have been obtained by insitu polymerization and the metal oxide/MWNTs were synthesized by sol-gel method. Morphological characterizations of polymer dispersed MWNTs have been carried out using scanning electron microscopy (SEM, transmission electron microscopy (TEM and HRTEM. An assymetric double supercapacitor stack has been fabricated using polymer/MWNTs and metal oxide/MWNTs coated over flexible carbon fabric as electrodes and nafion®membrane as a solid electrolyte. Electrochemical performance of the supercapacitor stack has been investigated using cyclic voltammetry, galvanostatic charge-discharge, and electrochemical impedance spectroscopy.

  3. The effects of human resource flexibility on human resources development

    Directory of Open Access Journals (Sweden)

    SeidMehdi Veise

    2014-08-01

    Full Text Available Human resources are the primary factor for development of competitiveness and innovation and reaching competitive advantage and they try to improve corporate capabilities through various characteristics such as value creation, scarcity and difficulty of imitation. This paper investigates the effect of human resource flexibility and its dimensions on human resource development and its dimensions. The survey was conducted using descriptive-correlation method that intended to describe how human resource flexibility was effective on human resource development. Questionnaire was tool of data collection. The statistical population included one hundred employees of the Electric Company in Ilam province, thus census method was used. Reliability of the questionnaire was measured via Cronbach's alpha equal to 0.96. The findings revealed that flexibility and its dimensions were effective on human resource development and dimensions of it. As a result, human resource flexibility should be considered for development of human resources and employees with the highest flexibility should be selected.

  4. Wind Turbines and Heat Pumps. Balancing wind power fluctuations using flexible demand

    International Nuclear Information System (INIS)

    Warmer, C.J.; Hommelberg, M.P.F.; Kamphuis, I.G.; Derszi, Z.; Kok, J.K.

    2007-01-01

    In order to overcome portfolio imbalance for traders of variable power from wind we have built an 'Imbalance Reduction System' (IRS) and performed a real-world field test with it, in which imbalance is minimized within a real-time electricity market portfolio, consisting of wind power and industrial and residential consumers and producers (Combined Heat and Power for district heating; residential heat pumps; industrial cold store; emergency generators). IRS uses the PowerMatcher concept, a coordination system for supply and demand of electricity in a which multi-agent system is combined with microeconomic principles. IRS appears to offer opportunities for embedding less predictable generators such as wind power more smoothly in the portfolio. We describe the context and operation of the Imbalance Reduction System and discuss a number of results from the performed field test. Also we introduce a business model for the balance responsible party, based on the e3-value method

  5. Computational analysis of chain flexibility and fluctuations in Rhizomucor miehei lipase

    DEFF Research Database (Denmark)

    Peters, Günther H.J.; Bywater, R. P.

    1999-01-01

    We have performed molecular dynamics simulation of Rhizomucor miehei lipase (Rml) with explicit water molecules present. The simulation was carried out in periodic boundary conditions and conducted for 1.2 ns in order to determine the concerted protein dynamics and to examine how well the essential...... motions are preserved along the trajectory. Protein motions are extracted by means of the essential dynamics analysis method for different lengths of the trajectory. Motions described by eigenvector 1 converge after approximately 200 ps and only small changes are observed with increasing simulation time....... Protein dynamics along eigenvectors with larger indices, however, change with simulation time and generally, with increasing eigenvector index, longer simulation times are required for observing similar protein motions (along a particular eigenvector). Several regions in the protein show relatively large...

  6. Covalent dye attachment influences the dynamics and conformational properties of flexible peptides.

    Directory of Open Access Journals (Sweden)

    Manuel P Luitz

    Full Text Available Fluorescence spectroscopy techniques like Förster resonance energy transfer (FRET and fluorescence correlation spectroscopy (FCS have become important tools for the in vitro and in vivo investigation of conformational dynamics in biomolecules. These methods rely on the distance-dependent quenching of the fluorescence signal of a donor fluorophore either by a fluorescent acceptor fluorophore (FRET or a non-fluorescent quencher, as used in FCS with photoinduced electron transfer (PET. The attachment of fluorophores to the molecule of interest can potentially alter the molecular properties and may affect the relevant conformational states and dynamics especially of flexible biomolecules like intrinsically disordered proteins (IDP. Using the intrinsically disordered S-peptide as a model system, we investigate the impact of terminal fluorescence labeling on the molecular properties. We perform extensive molecular dynamics simulations on the labeled and unlabeled peptide and compare the results with in vitro PET-FCS measurements. Experimental and simulated timescales of end-to-end fluctuations were found in excellent agreement. Comparison between simulations with and without labels reveal that the π-stacking interaction between the fluorophore labels traps the conformation of S-peptide in a single dominant state, while the unlabeled peptide undergoes continuous conformational rearrangements. Furthermore, we find that the open to closed transition rate of S-peptide is decreased by at least one order of magnitude by the fluorophore attachment. Our approach combining experimental and in silico methods provides a benchmark for the simulations and reveals the significant effect that fluorescence labeling can have on the conformational dynamics of small biomolecules, at least for inherently flexible short peptides. The presented protocol is not only useful for comparing PET-FCS experiments with simulation results but provides a strategy to minimize the

  7. Plasma diffusion due to magnetic field fluctuations

    International Nuclear Information System (INIS)

    Okuda, H.; Lee, W.W.; Lin, A.T.

    1979-01-01

    Plasma diffusion due to magnetic field fluctuations has been studied in two dimensions for a plasma near thermal equilibrium and when the fluctuations are suprathermal. It is found that near thermal equilibrium electron diffusion varies as B -2 when the collisionless skin depth is greater than the thermal electron gyroradius and is generally smaller than the diffusion due to collisions or electrostatic fluctuations for a low-β plasma. When the suprathermal magnetic fluctuation exists because of macroscopic plasma currents, electron diffusion is enhanced due to the coalescence of current filaments and magnetic islands. Magnetic field energy is found to condense to the longest wavelength available in the system and stays there longer than the electron diffusion time scale

  8. Magnetic fluctuations and heavy electron superconductivity

    International Nuclear Information System (INIS)

    Norman, M.R.

    1988-01-01

    A magnetic fluctuation self-energy based on neutron scattering data is used to calculate mass renormalizations, and superconducting critical temperatures and order parameters, for various heavy electron metals

  9. Metric fluctuations and their evolution during inflation

    International Nuclear Information System (INIS)

    Anabitarte, M.; Bellini, M.

    2004-01-01

    We discuss the evolution of the fluctuations in a symmetric φ c -exponential potential which provides a power-law expansion during inflation using both the gauge-invariant field Φ and the Sasaki-Mukhanov field. (orig.)

  10. Novikov Engine with Fluctuating Heat Bath Temperature

    Science.gov (United States)

    Schwalbe, Karsten; Hoffmann, Karl Heinz

    2018-04-01

    The Novikov engine is a model for heat engines that takes the irreversible character of heat fluxes into account. Using this model, the maximum power output as well as the corresponding efficiency of the heat engine can be deduced, leading to the well-known Curzon-Ahlborn efficiency. The classical model assumes constant heat bath temperatures, which is not a reasonable assumption in the case of fluctuating heat sources. Therefore, in this article the influence of stochastic fluctuations of the hot heat bath's temperature on the optimal performance measures is investigated. For this purpose, a Novikov engine with fluctuating heat bath temperature is considered. Doing so, a generalization of the Curzon-Ahlborn efficiency is found. The results can help to quantify how the distribution of fluctuating quantities affects the performance measures of power plants.

  11. Total charge fluctuation in heavy ion collision

    International Nuclear Information System (INIS)

    Mishra, D.K.; Netrakanti, P.K.; Mohanty, A.K.; Garg, P.

    2014-01-01

    Event-by-event fluctuations of positive, negative, total and net charge produced in relativistic nuclear collisions have been of interest to explore phase transition and/or a critical end point (CEP) which is believed to exist somewhere between the hadronic phase and the quark-gluon phase of the QCD phase diagram. The entropy is closely related to the particle multiplicity, and it is expected to be approximately conserved during the evolution of the matter created at the early stage. The entropy fluctuations are not directly observed but can be inferred from the experimentally measured quantities. The final state mean multiplicity is proportional to the entropy of the initial state ( ∼ S). The particle multiplicity can be measured on an event-by-event basis, whereas the entropy is defined by averaging the particle multiplicities in the ensemble of events. Thus, the dynamical entropy fluctuations can be measured experimentally by measuring the fluctuations in the mean multiplicity

  12. Fluctuations, dynamical instabilities and clusterization processes

    International Nuclear Information System (INIS)

    Burgio, G.F.; Chomaz, Ph.; Randrup, J.

    1992-01-01

    Recent progress with regard to the numerical simulation of fluctuations in nuclear dynamics is reported. Cluster formation in unstable nuclear matter is studied within the framework of a Boltzmann-Langevin equation developed to describe large amplitude fluctuations. Through the Fourier analysis of the fluctuating nuclear density in coordinate space, the onset of the clusterization is related to the dispersion relation of harmonic density oscillations. This detailed study on the simple two-dimensional case demonstrates the validity of the general approach. It is also shown, how the inclusion of fluctuations implies a description in terms of ensemble of trajectories and it is discussed why the presence of a stochastic term may cure the intrinsic unpredictability of deterministic theories (such as mean-field approximation) in presence of instabilities and/or chaos. (author) 8 refs., 3 figs

  13. Collective fluctuations in networks of noisy components

    International Nuclear Information System (INIS)

    Masuda, Naoki; Kawamura, Yoji; Kori, Hiroshi

    2010-01-01

    Collective dynamics result from interactions among noisy dynamical components. Examples include heartbeats, circadian rhythms and various pattern formations. Because of noise in each component, collective dynamics inevitably involve fluctuations, which may crucially affect the functioning of the system. However, the relation between the fluctuations in isolated individual components and those in collective dynamics is not clear. Here, we study a linear dynamical system of networked components subjected to independent Gaussian noise and analytically show that the connectivity of networks determines the intensity of fluctuations in the collective dynamics. Remarkably, in general directed networks including scale-free networks, the fluctuations decrease more slowly with system size than the standard law stated by the central limit theorem. They even remain finite for a large system size when global directionality of the network exists. Moreover, such non-trivial behavior appears even in undirected networks when nonlinear dynamical systems are considered. We demonstrate it with a coupled oscillator system.

  14. Fluctuations in the cosmic microwave background

    International Nuclear Information System (INIS)

    Banday, A.J.; Wolfendale, A.W.

    1990-01-01

    In view of the importance to contemporary cosmology, and to our understanding of the Universe, of the precise nature of the Cosmic Microwave Background (CMB) spectrum, we consider the effects on this spectrum of contamination by other radiation fields of both galactic and extragalactic origin. Particular attention is given to the significance of measurements of the fluctuations in the 'background' radiation detected at 10.46 GHz and we conclude that these fluctuations are of the same magnitude as those expected from galactic cosmic-ray effects. A more detailed study of the cosmic-ray induced fluctuations and measurements at higher frequencies will be needed before genuine CMB fluctuations can be claimed. (author)

  15. Edge fluctuation studies in Heliotron J

    International Nuclear Information System (INIS)

    Mizuuchi, T.; Chechkin, V.V.; Ohashi, K.; Sorokovoy, E.L.; Chechkin, A.V.; Gonchar, V.Yu.; Takahashi, K.; Kobayashi, S.; Nagasaki, K.; Okada, H.; Yamamoto, S.; Sano, F.; Kondo, K.; Nishino, N.; Kawazome, H.; Shidara, H.; Kaneko, S.; Fukagawa, Y.; Morita, Y.; Nakazawa, S.; Nishio, S.; Tsuboi, S.; Yamada, M.

    2005-01-01

    Low frequency and small-scale fluctuations of density and potential near the last closed flux surface are investigated by using Langmuir probes for the second harmonic ECH plasmas in a helical-axis heliotron device, Heliotron J. The existence of a plasma layer with a radial electric field shear was indicated near the last closed flux surface. Near this layer, the reversal of phase velocity and de-correlation of the fluctuations were observed. On the other hand, it is suggested that a considerable fraction of the fluctuation induced particle flux is carried off through the intermittent events. Preliminary analyses to classify the PDFs of the ion-saturation current fluctuation as stable Levy distributions demonstrate that the Levy index decreases from the inner to the outer region of edge plasma, suggesting that the PDFs near the boundary region of Heliotron J are nearly Gaussian, whereas at the outer regions of plasma they become strongly non-Gaussian

  16. Fluctuation conductivity of thin superconductive vanadium films

    International Nuclear Information System (INIS)

    Dmitrenko, I.M.; Sidorenko, A.S.; Fogel, N.Y.

    1982-01-01

    Resistive transitions into the superconductive state are studied in thin [d >T/sub c/ the experimental data on the excess conductivity of the films agree qualitatively and quantitively with Aslamazov--Larkin theory. There is no Maki--Thompson contribution to fluctuation conductivity. Near T/sub c/ the excess conductivity sigma' changes exponentially with temperature in accordance with the predictions of the theory of the critical fluctuations of the order parameter. The values of the effective charge carrier mass defined from data on sigma' for the low fluctuation and critical fluctuation regions differ markedly. This difference is within the spread of effective masses for various charge carrier groups already known for vanadium. Causes of the difference in resistive behavior for the regions T >T/sub c/ are considered

  17. Fluctuations at electrode-YSZ interfaces

    DEFF Research Database (Denmark)

    Jacobsen, Torben; Hansen, Karin Vels; Skou, Eivind

    2005-01-01

    Current fluctuations at potentiostatically controlled point electrodes of Pt, La$_{0.85}$Sr$_{0.15}$MnO$_3$ and Ni on YSZ surfaces are determined at 1000$^\\circ$C. For the oxygen reduction process on Pt electrodes characteristic sawtooth shaped low frequency fluctuations are observed. At temperat......Current fluctuations at potentiostatically controlled point electrodes of Pt, La$_{0.85}$Sr$_{0.15}$MnO$_3$ and Ni on YSZ surfaces are determined at 1000$^\\circ$C. For the oxygen reduction process on Pt electrodes characteristic sawtooth shaped low frequency fluctuations are observed....../water atmosphere are presented for discussion. The origin of the observations is not known at present but it appears likely that they are related to the activation/deactivation mechanism of SOFCs....

  18. Temperature fluctuations in the Atlantic Ocean

    International Nuclear Information System (INIS)

    Hjoello, Solfrid Saetre

    2005-01-01

    The article discusses the temperature fluctuations in connection with drought in Africa, the climate in North America, the European heat waves and the frequent tropical hurricanes in the Atlantic Ocean. Problems with climate modelling and some pollution aspects are mentioned

  19. Density Fluctuations in a Polar Coronal Hole

    Science.gov (United States)

    Hahn, Michael; D’Huys, Elke; Savin, Daniel Wolf

    2018-06-01

    We have measured the root-mean-square (rms) amplitude of intensity fluctuations, ΔI, in plume and interplume regions of a polar coronal hole. These intensity fluctuations correspond to density fluctuations. Using data from the Sun Watcher using the Active Pixel System detector and Image Processing on the Project for Onboard Autonomy (Proba2), our results extend up to a height of about 1.35 R ⊙. One advantage of the rms analysis is that it does not rely on a detailed evaluation of the power spectrum, which is limited by noise levels to low heights in the corona. The rms approach can be performed up to larger heights where the noise level is greater, provided that the noise itself can be quantified. At low heights, both the absolute ΔI, and the amplitude relative to the mean intensity, ΔI/I, decrease with height. However, starting at about 1.2 R ⊙, ΔI/I increases, reaching 20%–40% by 1.35 R ⊙. This corresponds to density fluctuations of Δn e/n e ≈ 10%–20%. The increasing relative amplitude implies that the density fluctuations are generated in the corona itself. One possibility is that the density fluctuations are generated by an instability of Alfvén waves. This generation mechanism is consistent with some theoretical models and with observations of Alfvén wave amplitudes in coronal holes. Although we find that the energy of the observed density fluctuations is small, these fluctuations are likely to play an important indirect role in coronal heating by promoting the reflection of Alfvén waves and driving turbulence.

  20. Density fluctuations in ohmic Asdex discharges

    International Nuclear Information System (INIS)

    Dodel, G.; Holzhauer, E.

    1989-01-01

    The investigations on the wave-number and frequency spectra of the density fluctuations, occurring in the different operational modes of ASDEX, are summarized. The aim of the experiments is to study the physical nature of fluctuations and their influence on anomalous transport. The scattering system is described. The results reported were obtained using a 100 mW, λ = 119 μm CW CH-30H laser and homodyne detection

  1. Fluorescence fluctuation spectroscopy (FFS), part A

    CERN Document Server

    Tetin, Sergey

    2013-01-01

    This new volume of Methods in Enzymology continues the legacy of this premier serial by containing quality chapters authored by leaders in the field. This volume covers Fluorescence Fluctuation SpectroscopyContains chapters on such topics as Time-integrated fluorescence cumulant analysis, Pulsed Interleaved Excitation, and raster image correlation spectroscopy and number and brightness analysis.Continues the legacy of this premier serial with quality chapters authored by leaders in the fieldCovers fluorescence fluctuation spectroscopyContains chapte

  2. Addendum to ''Density fluctuations in liquid rubidium''

    International Nuclear Information System (INIS)

    Haan, S.W.; Mountain, R.D.; Hsu, C.S.; Rahman, A.

    1980-01-01

    We performed molecular-dynamics simulations of liquid rubidium and the Lennard-Jones fluid at several densities and temperatures, and of a system whose pair potential is the repulsive core of the rubidium potential. In all cases, propagating density fluctuations occurred in the rubidiumlike systems at much shorter wavelengths than in the Lennard-Jones system. This indicates that the repulsive part of the pair potential is the dominant factor in determining the relaxation of short-wavelength density fluctuations

  3. Current fluctuations of interacting active Brownian particles

    OpenAIRE

    Pre, Trevor Grand; Limmer, David T.

    2018-01-01

    We derive the distribution function for particle currents for a system of interacting active Brownian particles in the long time limit using large deviation theory and a weighted many body expansion. We find the distribution is non-Gaussian, except in the limit of passive particles. The non-Gaussian fluctuations can be understood from the effective potential the particles experience when conditioned on a given current. This potential suppresses fluctuations of the particle's orientation, and ...

  4. Non-equilibrium fluctuation-induced interactions

    International Nuclear Information System (INIS)

    Dean, David S

    2012-01-01

    We discuss non-equilibrium aspects of fluctuation-induced interactions. While the equilibrium behavior of such interactions has been extensively studied and is relatively well understood, the study of these interactions out of equilibrium is relatively new. We discuss recent results on the non-equilibrium behavior of systems whose dynamics is of the dissipative stochastic type and identify a number of outstanding problems concerning non-equilibrium fluctuation-induced interactions.

  5. Propagation of disturbances as voltage fluctuations in transmission networks

    Directory of Open Access Journals (Sweden)

    Albert Hermina

    2016-08-01

    Full Text Available Significant changes occurred in the power system in Romania in recent years by reducing the power used in the system, the number of classic power sources in operation as well as by implementing renewable energy sources, have determined short circuit power reduction (node rigidity in the points where disturbing users are connected, that in the absence of adequate measures, result in disturbances above acceptable levels. The paper analyzes two power systems areas in which are connected users that cause voltage fluctuation. Disturbances as voltage fluctuations resulting in these nodes may exceed the acceptable values and can spread in the transmission network affecting power quality over large system areas. The analysis conducted reveals the influence of short circuit power in nodes where these users are connected and highlights the fact that in some cases (e.g. lines out of operation for maintenance, shutdown of classic units in the area the disturbances in the transmission network sent to the users at lower voltages may have values above those allowed. Technical Code of existing power transmission network makes no reference to voltage fluctuations, as a rule, in the electricity transmission network was considered that this phenomenon should not exist.

  6. Longitudinal fluctuations and decorrelation of anisotropic flow

    Energy Technology Data Exchange (ETDEWEB)

    Pang, Long-Gang [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, 60438 Frankfurt am Main (Germany); Petersen, Hannah [Frankfurt Institute for Advanced Studies, Ruth-Moufang-Strasse 1, 60438 Frankfurt am Main (Germany); Institute for Theoretical Physics, Goethe University, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main (Germany); GSI Helmholtzzentrum für Schwerionenforschung, Planckstr. 1, 64291 Darmstadt (Germany); Qin, Guang-You [Key Laboratory of Quark & Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079 (China); Roy, Victor [Institute for Theoretical Physics, Goethe University, Max-von-Laue-Strasse 1, 60438 Frankfurt am Main (Germany); Wang, Xin-Nian [Key Laboratory of Quark & Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079 (China); Nuclear Science Division MS70R0319, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 (United States)

    2016-12-15

    We investigate the decorrelation of 2nd and 3rd order anisotropic flow for charged particles in two different pseudo rapidity (η) windows by varying the pseudo rapidity gap, in an event-by-event (3+1)D ideal hydrodynamic model, with fluctuating initial conditions from A Multi-Phase Transport (AMPT) model. We visualize the parton distribution at initial state for Pb+Pb collisions at LHC and Au+Au collisions at RHIC, and demonstrate the longitudinal fluctuations originating from the asymmetry between forward and backward going participants, the fluctuations of the string length and the fluctuations due to finite number of partons at different beam energies. The decorrelation of anisotropic flow of final hadrons with large η gaps is found to originate from the spatial decorrelation along the longitudinal direction in the AMPT initial conditions through hydrodynamic evolution. The agreement between our results and recent CMS data in most centralities suggests that the string-like mechanism of initial parton production in AMPT model captures the initial longitudinal fluctuation that is responsible for the measured decorrelation of anisotropic flow in Pb+Pb collisions at LHC. Our predictions for Au+Au collisions at the highest RHIC energy show stronger longitudinal decorrelation than at LHC, indicating larger longitudinal fluctuations at lower beam energies.

  7. Origin of density fluctuations in extended inflation

    International Nuclear Information System (INIS)

    Kolb, E.W.; Salopek, D.S.; Turner, M.S.

    1990-01-01

    We calculate both the curvature and isocurvature density fluctuations that arise due to quantum fluctuations in a simple model of extended inflation based upon the Jordan-Brans-Dicke theory. The curvature fluctuations that arise due to quantum fluctuations in the Brans-Dicke field in general have a non-scale-invariant spectrum and an amplitude that is cosmologically acceptable and interesting without having to tune any coupling constant to a very small value. The curvature perturbations that arise due to the Higgs field are subdominant. If there are other massless fields in the theory, e.g., an axion or an ilion, then isocurvature fluctuations arise in these fields too. Production of gravitational waves and the massless particles associated with excitations of the Brans-Dicke field are also discussed. Several attempts at more realistic models of extended inflation are also analyzed. The importance of the Einstein conformal frame in calculating curvature fluctuations is emphasized. When viewed in this frame, extended inflation closely resembles slow-rollover inflation with an exponential potential, and the usual formula for the amplitude of curvature perturbations applies directly

  8. Origin of density fluctuations in extended inflation

    International Nuclear Information System (INIS)

    Kolb, E.W.; Salopek, D.S.; Turner, M.S.

    1990-05-01

    The density fluctuations (both curvature and isocurvature) that arise due to quantum fluctuations in a simple model of extended inflation based upon the Jordan-Brans-Dicke theory are calculated. Curvature fluctuations arise due to quantum fluctuations in the Brans-Dicke field, in general have a nonscale-invariant spectrum, and can have an amplitude that is cosmologically acceptable and interesting without having to tune any coupling constant to a very small value. The density perturbations that arise due to the inflation field are subdominant. If there are other massless fields in the theory, e.g., an axion or an ilion, then isocurvature fluctuations arise in these fields too. Production of gravitational waves and the massless particles associated with excitations of the Brans-Dicke field are also discussed. Several attempts at more realistic models of extended inflation are also analyzed. The importance of the Einstein conformal frame in calculating curvature fluctuations is emphasized. When viewed in this frame, extended inflation closely resembles slow-rollover inflation with an exponential potential and the usual formula for the amplitude of curvature perturbations applies

  9. On the assumption of vanishing temperature fluctuations at the wall for heat transfer modeling

    Science.gov (United States)

    Sommer, T. P.; So, R. M. C.; Zhang, H. S.

    1993-01-01

    Boundary conditions for fluctuating wall temperature are required for near-wall heat transfer modeling. However, their correct specifications for arbitrary thermal boundary conditions are not clear. The conventional approach is to assume zero fluctuating wall temperature or zero gradient for the temperature variance at the wall. These are idealized specifications and the latter condition could lead to an ill posed problem for fully-developed pipe and channel flows. In this paper, the validity and extent of the zero fluctuating wall temperature condition for heat transfer calculations is examined. The approach taken is to assume a Taylor expansion in the wall normal coordinate for the fluctuating temperature that is general enough to account for both zero and non-zero value at the wall. Turbulent conductivity is calculated from the temperature variance and its dissipation rate. Heat transfer calculations assuming both zero and non-zero fluctuating wall temperature reveal that the zero fluctuating wall temperature assumption is in general valid. The effects of non-zero fluctuating wall temperature are limited only to a very small region near the wall.

  10. On flexible and rigid nouns

    DEFF Research Database (Denmark)

    Rijkhoff, Jan

    2010-01-01

    classes. Finally this article wants to claim that the distinction between rigid and flexible noun categories (a) adds a new dimension to current classifications of parts of speech systems, (b) correlates with certain grammatical phenomena (e.g. so-called number discord), and (c) helps to explain the parts......This article argues that in addition to the major flexible lexical categories in Hengeveld’s classification of parts of speech systems (Contentive, Non-Verb, Modifier), there are also flexible word classes within the rigid lexical category Noun (Set Noun, Sort Noun, General Noun). Members...... by the flexible item in the external world. I will then argue that flexible word classes constitute a proper category (i.e. they are not the result of a merger of some rigid word classes) in that members of flexible word categories display the same properties regarding category membership as members of rigid word...

  11. On flexible and rigid nouns

    DEFF Research Database (Denmark)

    Rijkhoff, Jan

    2008-01-01

    Studies in Language 32-3 (2008), 727-752. Special issue: Parts of Speech: Descriptive tools, theoretical constructs Jan Rijkhoff - On flexible and rigid nouns This article argues that in addition to the flexible lexical categories in Hengeveld’s classification of parts-of-speech systems (Contentive......, Non-Verb, Modifier), there are also flexible word classes within the rigid lexical category Noun (Set Noun, Sort Noun, General Noun). Members of flexible word classes are characterized by their vague semantics, which in the case of nouns means that values for the semantic features Shape...... and Homogeneity are either left undetermined or they are specified in such a way that they do not quite match the properties of the kind of entity denoted by the flexible item in the external world. I will then argue that flexible word classes constitute a proper category (i.e. they are not the result of a merger...

  12. Flexible Language Interoperability

    DEFF Research Database (Denmark)

    Ekman, Torbjörn; Mechlenborg, Peter; Schultz, Ulrik Pagh

    2007-01-01

    Virtual machines raise the abstraction level of the execution environment at the cost of restricting the set of supported languages. Moreover, the ability of a language implementation to integrate with other languages hosted on the same virtual machine typically constrains the features...... of the language. In this paper, we present a highly flexible yet efficient approach to hosting multiple programming languages on an object-oriented virtual machine. Our approach is based on extending the interface of each class with language-specific wrapper methods, offering each language a tailored view...... of a given class. This approach can be deployed both on a statically typed virtual machine, such as the JVM, and on a dynamic virtual machine, such as a Smalltalk virtual machine. We have implemented our approach to language interoperability on top of a prototype virtual machine for embedded systems based...

  13. Flexible cultural repertoires

    DEFF Research Database (Denmark)

    Lindegaard, Marie Rosenkrantz; Zimmermann, Francisca

    2017-01-01

    Despite extensive studies of street culture and the risks of offending and victimization in urban marginalized areas, little is known about the role of cultural repertoires for variation in victimization risks among young men not involved in crime. Based on two ethnographic studies, conducted...... independently of the authors in neighbouring township areas of Cape Town, we offer insights into patterns of victimization among young men not involved in crime who live and attend school in the townships. Young men WHO perform decent cultural repertoires are highly exposed to victimization due to their moral...... rejection of crime-involved youth. Young men who perform flexible cultural repertoires, by incorporating and shifting between gang and decent repertoires, experience low victimization due to their adaptation to crime-involved youth. Findings emphasize the importance of detailed investigations of the way...

  14. Flexible helical yarn swimmers.

    Science.gov (United States)

    Zakharov, A P; Leshansky, A M; Pismen, L M

    2016-09-01

    We investigate the motion of a flexible Stokesian flagellar swimmer realised as a yarn made of two intertwined elastomer fibres, one active, that can reversibly change its length in response to a local excitation causing transition to the nematic state or swelling, and the other one, a passive isotropic elastomer with identical mechanical properties. A propagating chemical wave may provide an excitation mechanism ensuring a constant length of the excited region. Generally, the swimmer moves along a helical trajectory, and the propagation and rotation velocity are very sensitive to the ratio of the excited region to the pitch of the yarn, as well as to the size of a carried load. External excitation by a moving actuating beam is less effective, unless the direction of the beam is adjusted to rotation of the swimmer.

  15. Flexible weapons architecture design

    Science.gov (United States)

    Pyant, William C., III

    Present day air-delivered weapons are of a closed architecture, with little to no ability to tailor the weapon for the individual engagement. The closed architectures require weaponeers to make the target fit the weapon instead of fitting the individual weapons to a target. The concept of a flexible weapons aims to modularize weapons design using an open architecture shell into which different modules are inserted to achieve the desired target fractional damage while reducing cost and civilian casualties. This thesis shows that the architecture design factors of damage mechanism, fusing, weapons weight, guidance, and propulsion are significant in enhancing weapon performance objectives, and would benefit from modularization. Additionally, this thesis constructs an algorithm that can be used to design a weapon set for a particular target class based on these modular components.

  16. Conformational flexibility of aspartame.

    Science.gov (United States)

    Toniolo, Claudio; Temussi, Pierandrea

    2016-05-01

    L-Aspartyl-L-phenylalanine methyl ester, better known as aspartame, is not only one of the most used artificial sweeteners, but also a very interesting molecule with respect to the correlation between molecular structure and taste. The extreme conformational flexibility of this dipeptide posed a huge difficulty when researchers tried to use it as a lead compound to design new sweeteners. In particular, it was difficult to take advantage of its molecular model as a mold to infer the shape of the, then unknown, active site of the sweet taste receptor. Here, we follow the story of the 3D structural aspects of aspartame from early conformational studies to recent docking into homology models of the receptor. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 376-384, 2016. © 2016 Wiley Periodicals, Inc.

  17. Influence of thermal fluctuations on ligament break-up: a fluctuating lattice Boltzmann study

    Science.gov (United States)

    Xue, Xiao; Biferale, Luca; Sbragaglia, Mauro; Toschi, Federico

    2017-11-01

    Thermal fluctuations are essential ingredients in a nanoscale system, driving Brownian motion of particles and capillary waves at non-ideal interfaces. Here we study the influence of thermal fluctuations on the breakup of liquid ligaments at the nanoscale. We offer quantitative characterization of the effects of thermal fluctuations on the Plateau-Rayleigh mechanism that drives the breakup process of ligaments. Due to thermal fluctuations, the droplet sizes after break-up need to be analyzed in terms of their distribution over an ensemble made of repeated experiments. To this aim, we make use of numerical simulations based on the fluctuating lattice Boltzmann method (FLBM) for multicomponent mixtures. The method allows an accurate and efficient simulation of the fluctuating hydrodynamics equations of a binary mixture, where both stochastic viscous stresses and diffusion fluxes are introduced. This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie Grant Agreement No 642069.

  18. Employee satisfaction and use of flexible working arrangements

    OpenAIRE

    Wheatley, D

    2017-01-01

    This paper considers the impact of flexible working arrangements (FWAs), using the British Household Panel Survey and Understanding Society, 2001-2010/11. Results of panel logit, ANCOVA and change-score analysis are indicative of positive impacts from use of a number of FWAs, including homeworking having positive effects for men and women on job and leisure satisfaction. However,\\ud findings reveal gaps in availability and use of FWAs, and highlight the gendered nature of flexible employment....

  19. Information-to-free-energy conversion: Utilizing thermal fluctuations.

    Science.gov (United States)

    Toyabe, Shoichi; Muneyuki, Eiro

    2013-01-01

    Maxwell's demon is a hypothetical creature that can convert information to free energy. A debate that has lasted for more than 100 years has revealed that the demon's operation does not contradict the laws of thermodynamics; hence, the demon can be realized physically. We briefly review the first experimental demonstration of Maxwell's demon of Szilard's engine type that converts information to free energy. We pump heat from an isothermal environment by using the information about the thermal fluctuations of a Brownian particle and increase the particle's free energy.

  20. Mathematics revealed

    CERN Document Server

    Berman, Elizabeth

    1979-01-01

    Mathematics Revealed focuses on the principles, processes, operations, and exercises in mathematics.The book first offers information on whole numbers, fractions, and decimals and percents. Discussions focus on measuring length, percent, decimals, numbers as products, addition and subtraction of fractions, mixed numbers and ratios, division of fractions, addition, subtraction, multiplication, and division. The text then examines positive and negative numbers and powers and computation. Topics include division and averages, multiplication, ratios, and measurements, scientific notation and estim

  1. A Novel Assessment of Flexibility by Microcirculatory Signals

    Directory of Open Access Journals (Sweden)

    Jian-Guo Bau

    2013-12-01

    Full Text Available Flexibility testing is one of the most important fitness assessments. It is generally evaluated by measuring the range of motion (RoM of body segments around a joint center. This study presents a novel assessment of flexibility in the microcirculatory aspect. Eighteen college students were recruited for the flexibility assessment. The flexibility of the leg was defined according to the angle of active ankle dorsiflexion measured by goniometry. Six legs were excluded, and the remaining thirty legs were categorized into two groups, group H (n = 15 with higher flexibility and group L (n = 15 with lower flexibility, according to their RoM. The microcirculatory signals of the gastrocnemius muscle on the belly were monitored by using Laser-Doppler Flowmetry (LDF with a noninvasive skin probe. Three indices of nonpulsatile component (DC, pulsatile component (AC and perfusion pulsatility (PP were defined from the LDF signals after signal processing. The results revealed that both the DC and AC values of the group H that demonstrated higher stability underwent muscle stretching. In contrast, these indices of group L had interferences and became unstable during muscle stretching. The PP value of group H was a little higher than that of group L. These primary findings help us to understand the microcirculatory physiology of flexibility, and warrant further investigations for use of non-invasive LDF techniques in the assessment of flexibility.

  2. Studies of Fluctuation Processes in Nuclear Collisions

    Energy Technology Data Exchange (ETDEWEB)

    Ayik, Sakir [Tennessee Technological Univ., Cookeville, TN (United States). Dept. of Physics

    2016-04-14

    The standard one-body transport approaches have been extensively applied to investigate heavy-ion collision dynamics at low and intermediate energies. At low energies the approach is the mean-field description of the time-dependent Hartree-Fock (TDHF) theory. At intermediate energies the approach is extended by including a collision term, and its application has been carried out mostly in the semi-classical framework of the Boltzmann-Uhling-Uhlenbeck (BUU) model. The standard transport models provide a good understanding of the average properties of the collision dynamics in terms of the effective interactions in both low and intermediate energies. However, the standard models are inadequate for describing the fluctuation dynamics of collective motion at low energies and disassembling of the nuclear system into fragments at intermediate energies resulting from the growth of density fluctuations in the spinodal region. Our tasks have been to improve the standard transport approaches by incorporating fluctuation mechanisms into the description. There are mainly two different mechanisms for fluctuations: (i) Collisional fluctuations generated by binary nucleon collisions, which provide the dominant mechanism at intermediate energies, and (ii) One-body mechanism or mean-field fluctuations, which is the dominant mechanism at low energies. In the first part of our project, the PI extended the standard transport model at intermediate energies by incorporating collisional mechanism according to the “Generalized Langevin Description” of Mori formalism. The PI and his collaborators carried out a number of applications for describing dynamical mechanism of nuclear multi fragmentations, and nuclear collective response in the semi-classical framework of the approach, which is known as the Boltzmann-Langevin model. In the second part of the project, we considered dynamical description at low energies. Because of the effective Pauli blocking, the collisional dissipation and

  3. Species packing in eco-evolutionary models of seasonally fluctuating environments.

    Science.gov (United States)

    Kremer, Colin T; Klausmeier, Christopher A

    2017-09-01

    As ecology and evolution become ever more entwined, many areas of ecological theory are being re-examined. Eco-evolutionary analyses of classic coexistence mechanisms are yielding new insights into the structure and stability of communities. We examine fluctuation-dependent coexistence models, identifying communities that are both ecologically and evolutionarily stable. Members of these communities possess distinct environmental preferences, revealing widespread patterns of limiting similarity. This regularity leads to consistent changes in the structure of communities across fluctuation regimes. However, at high amplitudes, subtle differences in the form of fluctuations dramatically affect the collapse of communities. We also show that identical fluctuations can support multiple evolutionarily stable communities - a novel example of alternative stable states within eco-evolutionary systems. Consequently, the configuration of communities will depend on historical contingencies, including details of the adaptive process. Integrating evolution into the study of coexistence offers new insights, while enriching our understanding of ecology. © 2017 John Wiley & Sons Ltd/CNRS.

  4. Effect of spin fluctuations on the electronic structure in iron-based superconductors

    Science.gov (United States)

    Heimes, Andreas; Grein, Roland; Eschrig, Matthias

    2012-08-01

    Magnetic inelastic neutron scattering studies of iron-based superconductors reveal a strongly temperature-dependent spin-fluctuation spectrum in the normal conducting state, which develops a prominent low-energy resonance feature when entering the superconducting state. Angle-resolved photoemission spectroscopy (ARPES) and scanning tunneling spectroscopy (STS) allow us to study the fingerprints of fluctuation modes via their interactions with electronic quasiparticles. We calculate such fingerprints in 122 iron pnictides using an experimentally motivated spin-fluctuation spectrum and make a number of predictions that can be tested in ARPES and STS experiments. This includes discussions of the quasiparticle scattering rate and the superconducting order parameter. In quantitative agreement with experiment we reproduce the quasiparticle dispersions obtained from momentum distribution curves as well as energy distribution curves. We discuss the relevance of the coupling between spin fluctuations and electronic excitations for the superconducting mechanism.

  5. Investigation of the complexity of streamflow fluctuations in a large heterogeneous lake catchment in China

    Science.gov (United States)

    Ye, Xuchun; Xu, Chong-Yu; Li, Xianghu; Zhang, Qi

    2018-05-01

    The occurrence of flood and drought frequency is highly correlated with the temporal fluctuations of streamflow series; understanding of these fluctuations is essential for the improved modeling and statistical prediction of extreme changes in river basins. In this study, the complexity of daily streamflow fluctuations was investigated by using multifractal detrended fluctuation analysis (MF-DFA) in a large heterogeneous lake basin, the Poyang Lake basin in China, and the potential impacts of human activities were also explored. Major results indicate that the multifractality of streamflow fluctuations shows significant regional characteristics. In the study catchment, all the daily streamflow series present a strong long-range correlation with Hurst exponents bigger than 0.8. The q-order Hurst exponent h( q) of all the hydrostations can be characterized well by only two parameters: a (0.354 ≤ a ≤ 0.384) and b (0.627 ≤ b ≤ 0.677), with no pronounced differences. Singularity spectrum analysis pointed out that small fluctuations play a dominant role in all daily streamflow series. Our research also revealed that both the correlation properties and the broad probability density function (PDF) of hydrological series can be responsible for the multifractality of streamflow series that depends on watershed areas. In addition, we emphasized the relationship between watershed area and the estimated multifractal parameters, such as the Hurst exponent and fitted parameters a and b from the q-order Hurst exponent h( q). However, the relationship between the width of the singularity spectrum (Δ α) and watershed area is not clear. Further investigation revealed that increasing forest coverage and reservoir storage can effectively enhance the persistence of daily streamflow, decrease the hydrological complexity of large fluctuations, and increase the small fluctuations.

  6. Special Issue: Flexible Work Arrangements.

    Science.gov (United States)

    Olmstead, Barney, Ed.

    1996-01-01

    Section 1 contains five chapters on flexible work arrangements, self-employment, working from home, part-time professionals, job sharing, and temporary employment. Section 2 includes reviews of four books on working flexibly, concluding with a list of 23 additional readings. (SK)

  7. Measuring and Comparing Energy Flexibilities

    DEFF Research Database (Denmark)

    Valsomatzis, Emmanouil; Hose, Katja; Pedersen, Torben Bach

    2015-01-01

    induced by time and amount individually, and by their com- bination. To this end, we introduce several flexibility measures that take into account the combined effect of time and energy on flex-offer flexibility and discuss their respective pros and cons through a number of realistic examples....

  8. Sensor Technologies on Flexible Substrates

    Science.gov (United States)

    Koehne, Jessica

    2016-01-01

    NASA Ames has developed sensor technologies on flexible substrates integrated into textiles for personalized environment monitoring and human performance evaluation. Current technologies include chemical sensing for gas leak and event monitoring and biological sensors for human health and performance monitoring. Targeted integration include next generation EVA suits and flexible habitats.

  9. Functional aspects of protein flexibility

    DEFF Research Database (Denmark)

    Teilum, Kaare; Olsen, Johan G; Kragelund, Birthe B

    2009-01-01

    this into an intuitive perception of protein function is challenging. Flexibility is of overwhelming importance for protein function, and the changes in protein structure during interactions with binding partners can be dramatic. The present review addresses protein flexibility, focusing on protein-ligand interactions...

  10. Correlation length of magnetosheath fluctuations: Cluster statistics

    Directory of Open Access Journals (Sweden)

    O. Gutynska

    2008-09-01

    Full Text Available Magnetosheath parameters are usually described by gasdynamic or magnetohydrodynamic (MHD models but these models cannot account for one of the most important sources of magnetosheath fluctuations – the foreshock. Earlier statistical processing of a large amount of magnetosheath observations has shown that the magnetosheath magnetic field and plasma flow fluctuations downstream of the quasiparallel shock are much larger than those at the opposite flank. These studies were based on the observations of a single spacecraft and thus they could not provide full information on propagation of the fluctuations through the magnetosheath.

    We present the results of a statistical survey of the magnetosheath magnetic field fluctuations using two years of Cluster observations. We discuss the dependence of the cross-correlation coefficients between different spacecraft pairs on the orientation of the separation vector with respect to the average magnetic field and plasma flow vectors and other parameters. We have found that the correlation length does not exceed ~1 RE in the analyzed frequency range (0.001–0.125 Hz and does not depend significantly on the magnetic field or plasma flow direction. A close connection of cross-correlation coefficients computed in the magnetosheath with the cross-correlation coefficients between a solar wind monitor and a magnetosheath spacecraft suggests that solar wind structures persist on the background of magnetosheath fluctuations.

  11. General description of magnetic fluctuations in TEXT

    International Nuclear Information System (INIS)

    Kim, Y.J.

    1989-01-01

    The magnetic fluctuations in TEXT (R = 1m, a = 0.26m, ohmically heated tokamak with a full poloidal limiter) have been extensively measured with magnetic probes in the shadow of the limiter with an instrumental range of f -1 (m rms p (f > 50kHz) at the limiter radius is found to be of order 10 -5 T, which is too small to produce significant transport directly. Over the range of discharge parameters in TEXT, the B rms p (f > 50kHz) is observed to have a strong q a dependence (q a -2.2 ) and also a density dependence (n eo -0.8 ). Furthermore, the magnetic fluctuations show a significant correlation with edge electrostatic density fluctuations measured by Langmiur probe inside the limiter radius, and extending along magnetic field lines. Phase variation of the correlated components suggests k double-prime/k perpendicular ∼ 0.005. The B p rms (f >50kHz) is also found to be little dependent on parallel electric field E double-prime. Magnetic fluctuations in both low and high frequency ranges have been characterized by their response to gas puffing, pellet injection, impurity injection, and the effect of an ergodic magnetic limiter. The behavior of magnetic fluctuations with electron cyclotron resonance heating (ECRH) has been also investigated in detail

  12. Remarks on transport theories of interplanetary fluctuations

    International Nuclear Information System (INIS)

    Ye Zhou; Matthaeus, W.H.

    1990-01-01

    The structure of approximate transport theories for the radial behavior of interplanetary fluctuations is reconsidered. The emphasis is on theories derived under the assumption of scale separation; i.e., the correlation length of the fluctuations is much less than the scale of large inhomogeneities. In these cases the zero-wavelength limit provides a first approximation to the spectral evolution equations for the radial dependence of interplanetary fluctuation spectra. The goal here is to investigate the structure of a recently presented (Zhou and Matthaeus, 1989) transport theory, in which coupling of inward- and outward-type fluctuations appears in the leading order, an effect the authors call mixing. In linear theory, mixing-type couplings of inward-type and outward-type waves are formally a nonresonant effect. However, leading order mixing terms do not vanish at zero wavelength for fluctuations that vary nearly perpendicular to the local magnetic field, or when the mean magnetic field is weak. Leading order mixing terms also survive when the dispersion relation fails and there is a nonunique relationship between frequency and wave number. The former case corresponds to nearly two-dimensional structures; these are included, for example, in isotropic models of turbulence. The latter instance occurs when wave-wave couplings are sufficiently strong. Thus there are a variety of situations in which leading order mixing effects are expected to be present

  13. Correlation length of magnetosheath fluctuations: Cluster statistics

    Directory of Open Access Journals (Sweden)

    O. Gutynska

    2008-09-01

    Full Text Available Magnetosheath parameters are usually described by gasdynamic or magnetohydrodynamic (MHD models but these models cannot account for one of the most important sources of magnetosheath fluctuations – the foreshock. Earlier statistical processing of a large amount of magnetosheath observations has shown that the magnetosheath magnetic field and plasma flow fluctuations downstream of the quasiparallel shock are much larger than those at the opposite flank. These studies were based on the observations of a single spacecraft and thus they could not provide full information on propagation of the fluctuations through the magnetosheath. We present the results of a statistical survey of the magnetosheath magnetic field fluctuations using two years of Cluster observations. We discuss the dependence of the cross-correlation coefficients between different spacecraft pairs on the orientation of the separation vector with respect to the average magnetic field and plasma flow vectors and other parameters. We have found that the correlation length does not exceed ~1 RE in the analyzed frequency range (0.001–0.125 Hz and does not depend significantly on the magnetic field or plasma flow direction. A close connection of cross-correlation coefficients computed in the magnetosheath with the cross-correlation coefficients between a solar wind monitor and a magnetosheath spacecraft suggests that solar wind structures persist on the background of magnetosheath fluctuations.

  14. Fluctuation characteristics in detached recombining plasmas

    International Nuclear Information System (INIS)

    Ohno, Noriyasu; Tanaka, Naoyuki; Takamura, Shuichi; Budaev, Viatcheslav

    2002-01-01

    Fluctuation in detached recombining plasmas has been investigated experimentally in the linear divertor plasma simulator, NAGDIS-II. As increasing neutral gas pressure, floating potential fluctuation of the target plate installed at the end of the NADIS-II device becomes larger and bursty negative spikes are observed in the signal associated with a transition from attached to detached a plasmas. The fluctuation property has been analyzed by using Fast Fourier Transform (FFT), probability distribution function (PDF) and wavelet transform. The PDF of the floating potential fluctuation in the attached plasma condition obeys the Gaussian distribution function, on the other hand, the PDF in detached plasma shows a strong deviation from the Gaussian distribution function, which can be characterized by flatness and skewness. Comparison of the fluctuation properties between the floating potential and the optical emission from the detached plasma has been done based on the wavelet transform to show that a strong correlation between them, which could indicate bursty transport of energetic electrons from upstream to downstream region along the magnetic field. (author)

  15. Value of flexible consumption in the electricity markets

    DEFF Research Database (Denmark)

    Biegel, Benjamin; Hansen, Lars Henrik; Stoustrup, Jakob

    2014-01-01

    A transition from an oil and coal based energy system to a systems based on renewable and sustainable energy sources has begun in many countries throughout the developed world. As a pioneer, Denmark currently has a wind energy penetration of 30% in the electricity sector and an end goal of 100......% renewables in all energy sectors by 2050. The main elements in this transition are an increase in the wind energy production and electrification of main energy sectors such as transport and heating. Activation of flexible consumption in the electricity markets is believed to be one of the means to compensate...... for the growth of fluctuating renewables and the decrease of conventional power plants providing system-stabilizing services. In this work, we examine the requirements for flexible consumption to be active in the spot market and the regulating power market in the Nordic system and estimate the costs of entering...

  16. Interfering with the wake of cylinder by flexible filaments

    Science.gov (United States)

    Pinelli, Alfredo; Omidyeganeh, Mohammad

    2015-11-01

    This work is the very first attempt to understand and optimize the configuration of flexible filaments placed on the lee side of a bluff body to manipulate flow transitions and bifurcations. It is found that the presence of a sparse set of flexible filaments on the lee side of a cylinder can interfere with the 2D-3D transition process resulting in elongation of recirculation bubble, inhibition of higher order unstable modes, and narrowing the global energy content about a particular shedding frequency. Filaments become effective when spacing between them is smaller than the dominant unstable mode at each particular Reynolds number, i.e. A and B modes. In another study, by a particular arrangement the reconfigured filaments can reduce pressure fluctuations in the wake and drop lift flluctuations significantly (~= 80 %).

  17. Flexible operation of thermal plants with integrated energy storage technologies

    Science.gov (United States)

    Koytsoumpa, Efthymia Ioanna; Bergins, Christian; Kakaras, Emmanouil

    2017-08-01

    The energy system in the EU requires today as well as towards 2030 to 2050 significant amounts of thermal power plants in combination with the continuously increasing share of Renewables Energy Sources (RES) to assure the grid stability and to secure electricity supply as well as to provide heat. The operation of the conventional fleet should be harmonised with the fluctuating renewable energy sources and their intermittent electricity production. Flexible thermal plants should be able to reach their lowest minimum load capabilities while keeping the efficiency drop moderate as well as to increase their ramp up and down rates. A novel approach for integrating energy storage as an evolutionary measure to overcome many of the challenges, which arise from increasing RES and balancing with thermal power is presented. Energy storage technologies such as Power to Fuel, Liquid Air Energy Storage and Batteries are investigated in conjunction with flexible power plants.

  18. Modeling energy flexibility of low energy buildings utilizing thermal mass

    DEFF Research Database (Denmark)

    Foteinaki, Kyriaki; Heller, Alfred; Rode, Carsten

    2016-01-01

    In the future energy system a considerable increase in the penetration of renewable energy is expected, challenging the stability of the system, as both production and consumption will have fluctuating patterns. Hence, the concept of energy flexibility will be necessary in order for the consumption...... to match the production patterns, shifting demand from on-peak hours to off-peak hours. Buildings could act as flexibility suppliers to the energy system, through load shifting potential, provided that the large thermal mass of the building stock could be utilized for energy storage. In the present study...... the load shifting potential of an apartment of a low energy building in Copenhagen is assessed, utilizing the heat storage capacity of the thermal mass when the heating system is switched off for relieving the energy system. It is shown that when using a 4-hour preheating period before switching off...

  19. Flexible ring seal

    International Nuclear Information System (INIS)

    Abbes, Claude; Gournier, Andre; Rouaud, Christian; Villepoix, Raymond de.

    1976-01-01

    The invention concerns a flexible metal ring seal, able to ensure a perfect seal between two bearings due to the crushing and elastic deformation properties akin to similar properties in elastomers. Various designs of seal of this kind are already known, particularly a seal made of a core formed by a helical wire spring with close-wound turns and with high axial compression ratio, closed on itself and having the shape of an annulus. This wire ring is surrounded by at least one envelope having at rest the shape of a toroidal surface of which the generating circle does not close on itself. In a particular design mode, the seal in question can include, around the internal spring, two envelopes of which one in contact with the spring is composed of a low ductility elastic metal, such as mild steel or stainless steel and the other is, on the contrary, made of a malleable metal, such as copper or nickel. The first envelope evenly distributes the partial crushing of the spring, when the seal is tightened, on the second envelope which closely fits the two surfaces between which the seal operates. The stress-crushing curve characteristic of the seal comprises two separate parts, the first with a relatively sharp slope corresponds to the start of the seal compression phase, enabling at least some of these curves to reach the requisite seal threshold very quickly, then, beyond this, a second part, practically flat, where the stress is appreciably constant for a wide operating bracket [fr

  20. Flexible piezotronic strain sensor.

    Science.gov (United States)

    Zhou, Jun; Gu, Yudong; Fei, Peng; Mai, Wenjie; Gao, Yifan; Yang, Rusen; Bao, Gang; Wang, Zhong Lin

    2008-09-01

    Strain sensors based on individual ZnO piezoelectric fine-wires (PFWs; nanowires, microwires) have been fabricated by a simple, reliable, and cost-effective technique. The electromechanical sensor device consists of a single electrically connected PFW that is placed on the outer surface of a flexible polystyrene (PS) substrate and bonded at its two ends. The entire device is fully packaged by a polydimethylsiloxane (PDMS) thin layer. The PFW has Schottky contacts at its two ends but with distinctly different barrier heights. The I- V characteristic is highly sensitive to strain mainly due to the change in Schottky barrier height (SBH), which scales linear with strain. The change in SBH is suggested owing to the strain induced band structure change and piezoelectric effect. The experimental data can be well-described by the thermionic emission-diffusion model. A gauge factor of as high as 1250 has been demonstrated, which is 25% higher than the best gauge factor demonstrated for carbon nanotubes. The strain sensor developed here has applications in strain and stress measurements in cell biology, biomedical sciences, MEMS devices, structure monitoring, and more.

  1. Orthogonal flexible Rydberg aggregates

    Science.gov (United States)

    Leonhardt, K.; Wüster, S.; Rost, J. M.

    2016-02-01

    We study the link between atomic motion and exciton transport in flexible Rydberg aggregates, assemblies of highly excited light alkali-metal atoms, for which motion due to dipole-dipole interaction becomes relevant. In two one-dimensional atom chains crossing at a right angle adiabatic exciton transport is affected by a conical intersection of excitonic energy surfaces, which induces controllable nonadiabatic effects. A joint exciton-motion pulse that is initially governed by a single energy surface is coherently split into two modes after crossing the intersection. The modes induce strongly different atomic motion, leading to clear signatures of nonadiabatic effects in atomic density profiles. We have shown how this scenario can be exploited as an exciton switch, controlling direction and coherence properties of the joint pulse on the second of the chains [K. Leonhardt et al., Phys. Rev. Lett. 113, 223001 (2014), 10.1103/PhysRevLett.113.223001]. In this article we discuss the underlying complex dynamics in detail, characterize the switch, and derive our isotropic interaction model from a realistic anisotropic one with the addition of a magnetic bias field.

  2. SOCMA study urges flexibility

    International Nuclear Information System (INIS)

    Kirschner, E.

    1993-01-01

    In implementing the 1990 Pollution Prevention Act, regulators and legislators should hold off on cookie-cutter, numerical goal-based requirements to allow for site and process specific programs, says a study sponsored by the Synthetic Organic Chemicals Manufacturers Association (SOCMA; Washington). Companies should have that flexibility to target their resources toward those activities that reduce pollution cost effectively, says SOCMA environmental quality committee chairman Art Gillen, who is also BASF director of environmental regulatory affairs. The study - conducted by Woodward-Clyde Consultants (Denver) - examines four batch and custom chemical manufacturing films. As in the Clean Air Act, the batch processing of SOCMA-member plants should be considered in new regulations, Gillen says. For example, the study found that most wastes are from shutdowns and cleanouts, and there are frequent charges in waste streams and raw materials. Those characteristics do not lend themselves to annual reduction goals. Also, specific goals could have a wide range of costs: measures to reduce stack air emissions run from $18/lb to $1,106/lb. SOCMA says it will present the study to Congress and the Environmental Protection Agency

  3. Integrated engineering increases flexibility

    International Nuclear Information System (INIS)

    Smith, Ray

    1991-01-01

    Integrated Engineering (IE) can be used to describe the best use of increasingly rare good engineering talent in an increasingly competive world. A number of organisations are now moving towards IE without any general agreement on a precise definition. The engineering division of British Nuclear Fuels (BNFL) is one such organisation. This feature covers the reasoning behind the decision, and our experience to date. BNFL engineering division is responsible primarily for the provision of major facilities on BNFL operational sites. This provision includes feasibility, front end and detailed design, procurement, installation and commissioning. Task force working has been used for some of the large projects. But the future workload is expected to comprise many more smaller projects. At the same time, equipment is becoming more complex and the need for mutual understanding and appreciation between disciplines is increasing. To meet this increasing need for flexibility, BNFL has decided to move to the matrix structure of project management and functional departments described in the article. (Author)

  4. Thermal turbulent convection: thermal plumes and fluctuations; Convection thermique turbulente: panaches et fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Gibert, M

    2007-10-15

    In this study we investigate the phenomenon of thermal turbulent convection in new and unprecedented ways. The first system we studied experimentally is an infinite vertical channel, where a constant vertical mean gradient of temperature exists. Inside this channel the average mass flux is null. The results obtained from our measurements reveal that the flow is mainly inertial; indeed the dissipative coefficients (here the viscosity) play a role only to define a coherence length L. This length is the distance over which the thermal plumes can be considered as 'free falling' objects. The horizontal transport, of heat and momentum, is entirely due to fluctuations. The associated 'mixing length' is small compared to the channel width. In the other hand, the vertical heat transport is due to coherent structures: the heat plumes. Those objects were also investigated in a Lagrangian study of the flow in the bulk of a Rayleigh-Benard cell. The probe, which has the same density as the fluid used in this experiment, is a sphere of 2 cm in diameter with embarked thermometers and radio-emitter. The heat plumes transport it, which allows a statistical study of such objects. (author)

  5. Fluctuations and synchrony of RNA synthesis in nucleoli.

    Science.gov (United States)

    Pliss, Artem; Kuzmin, Andrey N; Kachynski, Aliaksandr V; Baev, Alexander; Berezney, Ronald; Prasad, Paras N

    2015-06-01

    Ribosomal RNA (rRNA) sequences are synthesized at exceptionally high rates and, together with ribosomal proteins (r-proteins), are utilized as building blocks for the assembly of pre-ribosomal particles. Although it is widely acknowledged that tight regulation and coordination of rRNA and r-protein production are fundamentally important for the maintenance of cellular homeostasis, still little is known about the real-time kinetics of the ribosome component synthesis in individual cells. In this communication we introduce a label-free MicroRaman spectrometric approach for monitoring rRNA synthesis in live cultured cells. Remarkably high and rapid fluctuations of rRNA production rates were revealed by this technique. Strikingly, the changes in the rRNA output were synchronous for ribosomal genes located in separate nucleoli of the same cell. Our findings call for the development of new concepts to elucidate the coordination of ribosomal components production. In this regard, numerical modeling further demonstrated that the production of rRNA and r-proteins can be coordinated, regardless of the fluctuations in rRNA synthesis. Overall, our quantitative data reveal a spectacular interplay of inherently stochastic rates of RNA synthesis and the coordination of gene expression.

  6. Magnetosheath density fluctuations and magnetopause motion

    Energy Technology Data Exchange (ETDEWEB)

    Sibeck, D.G. [Johns Hopkins Univ. Applied Physics Lab., Laurel, MD (United States); Gosling, J.T. [Los Alamos National Lab., NM (United States)

    1996-01-01

    The interplanetary magnetic field (IMF) orientation controls foreshock densities and modulates the fraction of the solar wind dynamic pressure applied to the magnetosphere. Such pressure variations produce bow shock and magnetopause motion and cause the radial profiles for various magnetosheath parameters to sweep inward and outward past nearly stationary satellites. The authors report ISEE 2 observations of correlated density and speed fluctuations, and anticorrelated density and temperature fluctuations, on an outbound pass through the northern dawnside magnetosheath. Densities decreased when the magnetic field rotated southward and draped about the magnetopause. In the absence of any significant solar wind density or dynamic pressure variations, they interpret the magnetosheath fluctuations as evidence for radial magnetosheath motion induced by variations in the IMF orientation. 41 refs., 8 figs.

  7. Fluctuation effects in bulk polymer phase behavior

    International Nuclear Information System (INIS)

    Bates, F.S.; Rosedale, J.H.; Stepanek, P.; Lodge, T.P.; Wiltzius, P.; Hjelm R, Jr.; Fredrickson, G.H.

    1990-01-01

    Bulk polymer-polymer, and block copolymer, phase behaviors have traditionally been interpreted using mean-field theories. Recent small-angle neutron scattering (SANS) studies of critical phenomena in model binary polymer mixtures confirm that non-mean-field behavior is restricted to a narrow range of temperatures near the critical point, in close agreement with the Ginzburg criterion. In contrast, strong derivations from mean-field behavior are evident in SANS and rheological measurements on model block copolymers more than 50C above the order-disorder transition (ODT), which can be attributed to sizeable composition fluctuations. Such fluctuation effects undermine the mean-field assumption, conventionally applied to bulk polymers, and result in qualitative changes in phase behavior, such as the elimination of a thermodynamic stability limit in these materials. The influence of fluctuation effects on block copolymer and binary mixture phase behavior is compared and contrasted in this presentation

  8. Classical and quantum temperature fluctuations via holography

    Energy Technology Data Exchange (ETDEWEB)

    Balatsky, Alexander V. [KTH Royal Inst. of Technology, Stockholm (Sweden); Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gudnason, Sven Bjarke [KTH Royal Inst. of Technology, Stockholm (Sweden); Thorlacius, Larus [KTH Royal Inst. of Technology, Stockholm (Sweden); University of Iceland, Reykjavik (Iceland); Zarembo, Konstantin [KTH Royal Inst. of Technology, Stockholm (Sweden); Inst. of Theoretical and Experimental Physics (ITEP), Moscow (Russian Federation); Uppsala Univ. (Sweden); Krikun, Alexander [KTH Royal Inst. of Technology, Stockholm (Sweden); Inst. of Theoretical and Experimental Physics (ITEP), Moscow (Russian Federation); Kedem, Yaron [KTH Royal Inst. of Technology, Stockholm (Sweden)

    2014-05-27

    We study local temperature fluctuations in a 2+1 dimensional CFT on the sphere, dual to a black hole in asymptotically AdS space-time. The fluctuation spectrum is governed by the lowest-lying hydrodynamic sound modes of the system whose frequency and damping rate determine whether temperature fluctuations are thermal or quantum. We calculate numerically the corresponding quasinormal frequencies and match the result with the hydrodynamics of the dual CFT at large temperature. As a by-product of our analysis we determine the appropriate boundary conditions for calculating low-lying quasinormal modes for a four-dimensional Reissner-Nordstrom black hole in global AdS.

  9. Stochastic dark energy from inflationary quantum fluctuations

    Science.gov (United States)

    Glavan, Dražen; Prokopec, Tomislav; Starobinsky, Alexei A.

    2018-05-01

    We study the quantum backreaction from inflationary fluctuations of a very light, non-minimally coupled spectator scalar and show that it is a viable candidate for dark energy. The problem is solved by suitably adapting the formalism of stochastic inflation. This allows us to self-consistently account for the backreaction on the background expansion rate of the Universe where its effects are large. This framework is equivalent to that of semiclassical gravity in which matter vacuum fluctuations are included at the one loop level, but purely quantum gravitational fluctuations are neglected. Our results show that dark energy in our model can be characterized by a distinct effective equation of state parameter (as a function of redshift) which allows for testing of the model at the level of the background.

  10. Force fluctuations assist nanopore unzipping of DNA

    International Nuclear Information System (INIS)

    Viasnoff, V; Chiaruttini, N; Muzard, J; Bockelmann, U

    2010-01-01

    We experimentally study the statistical distributions and the voltage dependence of the unzipping time of 45 base-pair-long double-stranded DNA through a nanopore. We then propose a quantitative theoretical description considering the nanopore unzipping process as a random walk of the opening fork through the DNA sequence energy landscape biased by a time-fluctuating force. To achieve quantitative agreement fluctuations need to be correlated over the millisecond range and have an amplitude of order k B T/bp. Significantly slower or faster fluctuations are not appropriate, suggesting that the unzipping process is efficiently enhanced by noise in the kHz range. We further show that the unzipping time of short 15 base-pair hairpins does not always increase with the global stability of the double helix and we theoretically study the role of DNA elasticity on the conversion of the electrical bias into a mechanical unzipping force.

  11. Maxwell electrodynamics subjected to quantum vacuum fluctuations

    International Nuclear Information System (INIS)

    Gevorkyan, A. S.; Gevorkyan, A. A.

    2011-01-01

    The propagation of electromagnetic waves in the vacuum is considered taking into account quantum fluctuations in the limits of Maxwell-Langevin (ML) equations. For a model of “white noise” fluctuations, using ML equations, a second order partial differential equation is found which describes the quantum distribution of virtual particles in vacuum. It is proved that in order to satisfy observed facts, the Lamb Shift etc, the virtual particles should be quantized in unperturbed vacuum. It is shown that the quantized virtual particles in toto (approximately 86 percent) are condensed on the “ground state” energy level. It is proved that the extension of Maxwell electrodynamics with inclusion of the vacuum quantum field fluctuations may be constructed on a 6D space-time continuum with a 2D compactified subspace. Their influence on the refraction indexes of vacuum is studied.

  12. Simultaneous measurement of 3 fluctuating plasma parameters

    International Nuclear Information System (INIS)

    Carlson, A.; Giannone, L.

    1991-01-01

    Langmuir triple probes can provide simultaneous measurements of n e , T e and V pl with good temporal and spatial resolution, and therefore are especially suited to detailed investigations of plasma turbulence in the scrape-off-layer. Unfortunately, the finite tip separation coupled with the fluctuating gradients prevents a simple interpretation of the results. We have developed a method using, essentially, two or more triple probes, which allows a good estimate of the three plasma parameters and their spatial derivatives at each point of time (assuming tip separation is much less than correlation length and dimensionless fluctuation levels are much less than unity). In particular, we can unambiguously measure the temperature fluctuations and the turbulent particle and heat flux. (author) 1 fig

  13. Simultaneous measurement of 3 fluctuating plasma parameters

    International Nuclear Information System (INIS)

    Carlson, A.; Giannone, L.

    1991-01-01

    Langmuir triple probes can provide simultaneous measurements of n e , T e , and V pl with good temporal and spatial resolution, and therefore are especially suited to detailed investigations of plasma turbulence in the scrape-off-layer. Unfortunately, the finite tip separation coupled with the fluctuating gradients prevents a simple interpretation of the results. We have developed a method using, essentially, two or more triple probes, which allows a good estimate of the three plasma parameters and their spatial derivatives at each point of time (assuming tip separation is much less than correlation length and dimensionless fluctuation levels are much less than unity). In particular, we can unambiguously measure the temperature fluctuations and the turbulent particle and heat flux. (orig.)

  14. Simultaneous measurement of 3 fluctuating plasma parameters

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, A; Giannone, L. (Max-Planck-Institut fuer Plasmaphysik, Garching (Germany))

    1991-01-01

    Langmuir triple probes can provide simultaneous measurements of n[sub e], T[sub e] and V[sub pl] with good temporal and spatial resolution, and therefore are especially suited to detailed investigations of plasma turbulence in the scrape-off-layer. Unfortunately, the finite tip separation coupled with the fluctuating gradients prevents a simple interpretation of the results. We have developed a method using, essentially, two or more triple probes, which allows a good estimate of the three plasma parameters and their spatial derivatives at each point of time (assuming tip separation is much less than correlation length and dimensionless fluctuation levels are much less than unity). In particular, we can unambiguously measure the temperature fluctuations and the turbulent particle and heat flux. (author) 1 fig.

  15. RSA fluctuation in major depressive disorder.

    Science.gov (United States)

    Rottenberg, Jonathan; Clift, April; Bolden, Sarah; Salomon, Kristen

    2007-05-01

    Cardiac vagal control, as measured by indices of respiratory sinus arrhythmia (RSA), has been investigated as a marker of impaired self-regulation in mental disorders, including depression. Past work in depressed samples has focused on deficits in resting RSA levels, with mixed results. This study tested the hypothesis that depression involves abnormal RSA fluctuation. RSA was measured in depressed and healthy control participants during rest and during two reactivity tasks, each followed by a recovery period. Relative to controls, depressed persons exhibited lower resting RSA levels as well as less RSA fluctuation, primarily evidenced by a lack of task-related vagal suppression. Group differences in RSA fluctuation were not accounted for by differences in physical health or respiration, whereas group differences in resting RSA level did not survive covariate analyses. Depression may involve multiple deficits in cardiac vagal control.

  16. Fluctuation diamagnetism in two-band superconductors

    Science.gov (United States)

    Adachi, Kyosuke; Ikeda, Ryusuke

    2016-04-01

    Anomalously large fluctuation diamagnetism around the superconducting critical temperature has been recently observed in iron selenide (FeSe) [Kasahara et al. (unpublished)]. This indicates that superconducting fluctuations (SCFs) play a more significant role in FeSe, which supposedly has a two-band structure, than in the familiar single-band superconductors. Motivated by the data on FeSe, SCF-induced diamagnetism is examined in a two-band system, on the basis of a phenomenological approach with a Ginzburg-Landau functional. The obtained results indicate that the SCF-induced diamagnetism may be more enhanced than that in a single-band system due to the existence of two distinct fluctuation modes. Such enhancement of diamagnetism unique to a two-band system seems consistent with the large diamagnetism observed in FeSe, though still far from a quantitative agreement.

  17. Extracellular matrix fluctuations during early embryogenesis

    International Nuclear Information System (INIS)

    Szabó, A; Rupp, P A; Rongish, B J; Little, C D; Czirók, A

    2011-01-01

    Extracellular matrix (ECM) movements and rearrangements were studied in avian embryos during early stages of development. We show that the ECM moves as a composite material, whereby distinct molecular components as well as spatially separated layers exhibit similar displacements. Using scanning wide field and confocal microscopy we show that the velocity field of ECM displacement is smooth in space and that ECM movements are correlated even at locations separated by several hundred micrometers. Velocity vectors, however, strongly fluctuate in time. The autocorrelation time of the velocity fluctuations is less than a minute. Suppression of the fluctuations yields a persistent movement pattern that is shared among embryos at equivalent stages of development. The high resolution of the velocity fields allows a detailed spatio-temporal characterization of important morphogenetic processes, especially tissue dynamics surrounding the embryonic organizer (Hensen's node)

  18. Faraday polarization fluctuations of satellite beacon signals

    Science.gov (United States)

    Lee, M. C.; Klobuchar, J. A.

    1988-01-01

    The anisotropic effects of random density irregularities in causing Faraday polarization fluctuations of VHF radio signals are examined, taking both rod-like and sheet-like irregularities into consideration. It is found that the variance of Faraday polarization fluctuations depends on the ratio of perpendicular to parallel correlation lengths. The anisotropic effect of rod-like ionospheric irregularities are shown to be most appreciable for longitudinal propagation. The anisotropic effect of sheet-like ionospheric irregularities, however, is not strongly dependent on the radio propagation angle. During transionospheric propagation at large angles with respect to the geomagnetic field, sheet-like irregularities may cause greater Faraday polarization fluctuations than rod-like irregularities.

  19. Impact of Precipitation Fluctuation on Desert-Grassland ANPP

    Directory of Open Access Journals (Sweden)

    Liangxu Liu

    2016-11-01

    Full Text Available Precipitation change has significantly influenced annual net primary productivity (ANPP at either annual or seasonal scales in desert steppes in arid and semi-arid regions. In order to reveal the process of precipitation driving ANPP at different time scales, responses of different ANPP levels to the inter-annual and intra-annual precipitation fluctuations were analyzed. ANPP was reversed by building a ground reflectance spectrum model, from 2000 to 2015, using the normalized differential vegetation index of the Moderate-Resolution Imaging Spectroradiometer (MODIS-NDVI data at 250 m × 250 m spatial resolution. Since the description of the differently expressing forms of precipitation are not sufficient in former studies in order to overcome the deficiency of former studies, in this study, intra-annual precipitation fluctuations were analyzed not only with precipitation of May–August, June–August, July–August, and August, respectively, which have direct influence on vegetation productivity within the year, but quantitative description, vector precipitation (R, concentration ratio (Cd, and concentration period (D, were also used to describe the overall characteristics of intra-annual precipitation fluctuations. The concentration ratio and the maximum precipitation period of the intra-annual precipitation were represented by using monthly precipitation. The results showed that: (1 in the period from 1971 to 2015, the maximum annual precipitation is 3.76 times that of the minimum in the Urat desert steppe; (2 vector precipitation is more significantly related to ANPP (r = 0.7724, p = 0.000 compared to meteorological annual precipitation and real annual precipitation influence; and (3 annual precipitation is almost concentrated in 5–8 months and monthly precipitation accumulation has significantly effected ANPP, especially in the period of June–August, since the vegetation composition in the study area was mainly sub-shrubs and perennial

  20. Qualification test for the flexible receiver

    International Nuclear Information System (INIS)

    Keller, C.M.

    1994-01-01

    This document provides the test plan and procedures to certify and design verify the 42 inch and 4--6 inch Flexible Receiver (FR) is a safety class 3 system. Verification of the design will be handled in two parts. The first part will be to show that it meets design requirements set forth by documents and the second part will perform test(s) to verify its operational aspects. To qualify the design of the FR systems for field use this test will demonstrate environmentally safe removal of a Tank Farm pump mock-up from a Tank Farm riser mock-up. Testing will also demonstrate the performance of supporting equipment. The FR and the Secondary Bagging (SB) equipment shall be tested to verify successful operation of the equipment to the following criteria: The FR can be placed on a riser and connections made to the supporting equipment; The FR bag can accept equipment and be successfully sealed; The SB system encases the seal of the primary FR bag; The flexible bag(s) do not tear and maintain integrity during the entire test; The FR control system operates in the fail safe forced sequence mode; The FR control system will operate in the manual override mode (out of sequence operations); The CCTV Video system monitors and records the removal of the test item; The spray wash system operates without leaks and effectively provides coverage; The item being removed can be reinserted to a depth of 8 feet and the bag reinstalled onto the vertical bag supports; and The system prohibits momentary mechanical fluctuations due to the application of system power, including power interruptions

  1. Inverse scattering problem in turbulent magnetic fluctuations

    Directory of Open Access Journals (Sweden)

    R. A. Treumann

    2016-08-01

    Full Text Available We apply a particular form of the inverse scattering theory to turbulent magnetic fluctuations in a plasma. In the present note we develop the theory, formulate the magnetic fluctuation problem in terms of its electrodynamic turbulent response function, and reduce it to the solution of a special form of the famous Gelfand–Levitan–Marchenko equation of quantum mechanical scattering theory. The last of these applies to transmission and reflection in an active medium. The theory of turbulent magnetic fluctuations does not refer to such quantities. It requires a somewhat different formulation. We reduce the theory to the measurement of the low-frequency electromagnetic fluctuation spectrum, which is not the turbulent spectral energy density. The inverse theory in this form enables obtaining information about the turbulent response function of the medium. The dynamic causes of the electromagnetic fluctuations are implicit to it. Thus, it is of vital interest in low-frequency magnetic turbulence. The theory is developed until presentation of the equations in applicable form to observations of turbulent electromagnetic fluctuations as input from measurements. Solution of the final integral equation should be done by standard numerical methods based on iteration. We point to the possibility of treating power law fluctuation spectra as an example. Formulation of the problem to include observations of spectral power densities in turbulence is not attempted. This leads to severe mathematical problems and requires a reformulation of inverse scattering theory. One particular aspect of the present inverse theory of turbulent fluctuations is that its structure naturally leads to spatial information which is obtained from the temporal information that is inherent to the observation of time series. The Taylor assumption is not needed here. This is a consequence of Maxwell's equations, which couple space and time evolution. The inversion procedure takes

  2. Deriving GENERIC from a Generalized Fluctuation Symmetry

    Science.gov (United States)

    Kraaij, Richard; Lazarescu, Alexandre; Maes, Christian; Peletier, Mark

    2018-02-01

    Much of the structure of macroscopic evolution equations for relaxation to equilibrium can be derived from symmetries in the dynamical fluctuations around the most typical trajectory. For example, detailed balance as expressed in terms of the Lagrangian for the path-space action leads to gradient zero-cost flow. We expose a new such fluctuation symmetry that implies GENERIC, an extension of gradient flow where a Hamiltonian part is added to the dissipative term in such a way as to retain the free energy as Lyapunov function.

  3. Spin fluctuation theory of itinerant electron magnetism

    CERN Document Server

    Takahashi, Yoshinori

    2013-01-01

    This volume shows how collective magnetic excitations determine most of  the magnetic properties of itinerant electron magnets. Previous theories were mainly restricted to the Curie-Weiss law temperature dependence of magnetic susceptibilities. Based on the spin amplitude conservation idea including the zero-point fluctuation amplitude, this book shows that the entire temperature and magnetic field dependence of magnetization curves, even in the ground state, is determined by the effect of spin fluctuations. It also shows that the theoretical consequences are largely in agreement with many experimental observations. The readers will therefore gain a new comprehensive perspective of their unified understanding of itinerant electron magnetism.

  4. Fluctuation of heat current in Josephson junctions

    Directory of Open Access Journals (Sweden)

    P. Virtanen

    2015-02-01

    Full Text Available We discuss the statistics of heat current between two superconductors at different temperatures connected by a generic weak link. As the electronic heat in superconductors is carried by Bogoliubov quasiparticles, the heat transport fluctuations follow the Levitov–Lesovik relation. We identify the energy-dependent quasiparticle transmission probabilities and discuss the resulting probability density and fluctuation relations of the heat current. We consider multichannel junctions, and find that heat transport in diffusive junctions is unique in that its statistics is independent of the phase difference between the superconductors.

  5. Universal conductance fluctuations in disordered metals

    International Nuclear Information System (INIS)

    Lee, P.A.

    1987-01-01

    The author argues that observed and theoretical fluctuations in the electrical conductance of disordered metals, induced by variations in the magnetic field or the chemical potential, are not time-dependent noise but that the conductance is a deterministic albeit fluctuating function for a given realization of the impurity configuration. A method is constructed for representing the sensitivity of the conductance of a given metal to a small change in the impurity configuration as a function of such variables as sample size, impurities per unit volume, and mean free path. The sensitivity helps explain the size of 1/f noise due to defect motion in disordered metals

  6. Primordial black holes from passive density fluctuations

    International Nuclear Information System (INIS)

    Lin, Chia-Min; Ng, Kin-Wang

    2013-01-01

    In this Letter, we show that if passive fluctuations are considered, primordial black holes (PBHs) can be easily produced in the framework of single-field, slow-roll inflation models. The formation of PBHs is due to the blue spectrum of passive fluctuations and an enhancement of the spectral range which exits horizon near the end of inflation. Therefore the PBHs are light with masses ≲10 15 g depending on the number of e-folds when the scale of our observable universe leaves horizon. These PBHs are likely to have evaporated and cannot be a candidate for dark matter but they may still affect the early universe.

  7. Primordial black holes from passive density fluctuations

    OpenAIRE

    Lin, Chia-Min; Ng, Kin-Wang

    2013-01-01

    In this paper, we show that if passive fluctuations are considered, primordial black holes (PBHs) can be easily produced in the framework of single-field, slow-roll inflation models. The formation of PBHs is due to the blue spectrum of passive fluctuations and an enhancement of the spectral range which exits horizon near the end of inflation. Therefore the PBHs are light with masses $\\lesssim 10^{15}g$ depending on the number of e-folds when the scale of our observable universe leaves horizon...

  8. Crossover transition in the fluctuation of Internet

    Science.gov (United States)

    Qian, Jiang-Hai

    2018-06-01

    The inconsistent fluctuation behavior of Internet predicted by preferential attachment(PA) and Gibrat's law requires empirical investigations on the actual system. By using the interval-tunable Gibrat's law statistics, we find the actual fluctuation, characterized by the conditional standard deviation of the degree growth rate, changes with the interval length and displays a crossover transition from PA type to Gibrat's law type, which has not yet been captured by any previous models. We characterize the transition dynamics quantitatively and determine the applicative range of PA and Gibrat's law. The correlation analysis indicates the crossover transition may be attributed to the accumulative correlation between the internal links.

  9. Fluctuations in high-energy particle collisions

    International Nuclear Information System (INIS)

    Gronqvist, Hanna

    2016-01-01

    We study fluctuations that are omnipresent in high-energy particle collisions. These fluctuations can be either of either classical or quantum origin and we will study both. Firstly, we consider the type of quantum fluctuations that arise in proton-proton collisions. These are computable perturbatively in quantum field theory and we will focus on a specific class of diagrams in this set-up. Secondly, we will consider the fluctuations that are present in collisions between nuclei that can be heavier than protons. These are the quantum laws of nature that describe the positions of nucleons within a nucleus, but also the hydrodynamic fluctuations of classical, thermal origin that affect the evolution of the medium produced in heavy-ion collisions. The fluctuations arising in proton-proton collisions can be computed analytically up to a certain order in perturbative quantum field theory. We will focus on one-loop diagrams of a fixed topology. Loop diagrams give rise to integrals that typically are hard to evaluate. We show how modern mathematical methods can be used to ease their computation. We will study the relations among unitarity cuts of a diagram, the discontinuity across the corresponding branch cut and the coproduct. We show how the original integral corresponding to a given diagram can be reconstructed from the information contained in the coproduct. We expect that these methods can be applied to solve more complicated topologies and help in the computation of new amplitudes in the future. Finally, we study the two types of fluctuations arising in heavy-ion collisions. These are related either to the initial state or the intermediate state of matter produced in such collisions. The initial state fluctuations are experimentally observed to give rise to non-Gaussianities in the final-state spectra. We show how these non-Gaussianities can be explained by the random position and interaction energy of 'sources' in the colliding nuclei. Furthermore, we

  10. Dissipative neutrino oscillations in randomly fluctuating matter

    International Nuclear Information System (INIS)

    Benatti, F.; Floreanini, R.

    2005-01-01

    The generalized dynamics describing the propagation of neutrinos in randomly fluctuating media is analyzed: It takes into account matter-induced, decoherence phenomena that go beyond the standard Mikheyev-Smirnov-Wolfenstein (MSW) effect. A widely adopted density fluctuation pattern is found to be physically untenable: A more general model needs to be instead considered, leading to flavor changing effective neutrino-matter interactions. They induce new, dissipative effects that modify the neutrino oscillation pattern in a way amenable to a direct experimental analysis

  11. Dissipative neutrino oscillations in randomly fluctuating matter

    Science.gov (United States)

    Benatti, F.; Floreanini, R.

    2005-01-01

    The generalized dynamics describing the propagation of neutrinos in randomly fluctuating media is analyzed: It takes into account matter-induced, decoherence phenomena that go beyond the standard Mikheyev-Smirnov-Wolfenstein (MSW) effect. A widely adopted density fluctuation pattern is found to be physically untenable: A more general model needs to be instead considered, leading to flavor changing effective neutrino-matter interactions. They induce new, dissipative effects that modify the neutrino oscillation pattern in a way amenable to a direct experimental analysis.

  12. Fluctuations and localization in mesoscopic electron

    CERN Document Server

    Janssen, Martin

    2001-01-01

    The quantum phenomena of tunneling and interference show up not only in the microscopic world of atoms and molecules, but also in cold materials of the real world, such as metals and semiconductors. Though not fully macroscopic, such mesoscopic systems contain a huge number of particles, and the holistic nature of quantum mechanics becomes evident already in simple electronic measurements. The measured quantity fluctuates as a function of applied fields in an unpredictable, yet reproducible way. Despite this fingerprint character of fluctuations, their statistical properties are universal, i.e

  13. Parametric Amplification of Gravitational Fluctuations during Reheating

    International Nuclear Information System (INIS)

    Finelli, F.; Brandenberger, R.; Finelli, F.

    1999-01-01

    Cosmological perturbations can undergo amplification by parametric resonance during preheating even on scales larger than the Hubble radius, without violating causality. A unified description of gravitational and matter fluctuations is crucial to determine the strength of the instability. To extract specific signatures of the oscillating inflaton field during reheating, it is essential to focus on a variable describing metric fluctuations which is constant in the standard analyses of inflation. For a massive inflaton without self-coupling, we find no additional growth of superhorizon modes during reheating beyond the usual predictions. For a massless self-coupled inflaton, there is a sub-Hubble scale resonance. copyright 1999 The American Physical Society

  14. Particle transport due to magnetic fluctuations

    International Nuclear Information System (INIS)

    Stoneking, M.R.; Hokin, S.A.; Prager, S.C.; Fiksel, G.; Ji, H.; Den Hartog, D.J.

    1994-01-01

    Electron current fluctuations are measured with an electrostatic energy analyzer at the edge of the MST reversed-field pinch plasma. The radial flux of fast electrons (E>T e ) due to parallel streaming along a fluctuating magnetic field is determined locally by measuring the correlated product e B r >. Particle transport is small just inside the last closed flux surface (Γ e,mag e,total ), but can account for all observed particle losses inside r/a=0.8. Electron diffusion is found to increase with parallel velocity, as expected for diffusion in a region of field stochasticity

  15. Flexibility in fuel manufacturing

    International Nuclear Information System (INIS)

    Reparaz, A.; Stavig, W.E.; McLees, R.B.

    1987-01-01

    From its inception Exxon Nuclear has produced both BWR and PWR fuels. This is reflected in a product line that, to date, includes over 20 fuel designs. These range from 6x6 design at one end of the spectrum to the recently introduced 17x17 design. The benefits offered include close tailoring of the fuel design to match the customer's requirements, and the ability to rapidly introduce product changes, such as the axial blanket design, with a minimal impact on manufacturing. This flexibility places a number of demands on the manufacturing organization. Close interfaces must be established, and maintained, between the marketing, product design, manufacturing, purchasing and quality organizations, and the information flows must be immediate and accurate. Production schedules must be well planned and must be maintained or revised to reflect changing circumstances. Finally, the manufacturing facilities must be designed to allow rapid switchover between product designs with minor tooling changes and/or rerouting of product flows to alternate work stations. Among the tools used to manage the flow of information and to maintain the tight integration necessary between the various manufacturing, engineering and quality organizations is a commercially available, computerized planning and tracking system, AMAPS. A real-time production data collection system has been designed which gathers data from each production work station for use by the shop floor control module of AMAPS. Accuracy of input to the system is improved through extensive use of bar codes to gather information on the product as it moves through and between work stations. This computerized preparation of material tracing has an impact on direct manufacturing records, quality control records, nuclear material records and accounting and inventory records. This is of benefit to both Exxon Nuclear and its customers

  16. Revealing Rembrandt

    Directory of Open Access Journals (Sweden)

    Andrew J Parker

    2014-04-01

    Full Text Available The power and significance of artwork in shaping human cognition is self-evident. The starting point for our empirical investigations is the view that the task of neuroscience is to integrate itself with other forms of knowledge, rather than to seek to supplant them. In our recent work, we examined a particular aspect of the appreciation of artwork using present-day functional magnetic resonance imaging (fMRI. Our results emphasised the continuity between viewing artwork and other human cognitive activities. We also showed that appreciation of a particular aspect of artwork, namely authenticity, depends upon the co-ordinated activity between the brain regions involved in multiple decision making and those responsible for processing visual information. The findings about brain function probably have no specific consequences for understanding how people respond to the art of Rembrandt in comparison with their response to other artworks. However, the use of images of Rembrandt’s portraits, his most intimate and personal works, clearly had a significant impact upon our viewers, even though they have been spatially confined to the interior of an MRI scanner at the time of viewing. Neuroscientific studies of humans viewing artwork have the capacity to reveal the diversity of human cognitive responses that may be induced by external advice or context as people view artwork in a variety of frameworks and settings.

  17. Workforce flexibility - in defence of professional healthcare work.

    Science.gov (United States)

    Wise, Sarah; Duffield, Christine; Fry, Margaret; Roche, Michael

    2017-06-19

    Purpose The desirability of having a more flexible workforce is emphasised across many health systems yet this goal is as ambiguous as it is ubiquitous. In the absence of empirical studies in healthcare that have defined flexibility as an outcome, the purpose of this paper is to draw on classic management and sociological theory to reduce this ambiguity. Design/methodology/approach The paper uses the Weberian tool of "ideal types". Key workforce reforms are held against Atkinson's model of functional flexibility which aims to increase responsiveness and adaptability through multiskilling, autonomy and teams; and Taylorism which seeks stability and reduced costs through specialisation, fragmentation and management control. Findings Appeals to an amorphous goal of increasing workforce flexibility make an assumption that any reform will increase flexibility. However, this paper finds that the work of healthcare professionals already displays most of the essential features of functional flexibility but many widespread reforms are shifting healthcare work in a Taylorist direction. This contradiction is symptomatic of a failure to confront inevitable trade-offs in reform: between the benefits of specialisation and the costs of fragmentation; and between management control and professional autonomy. Originality/value The paper questions the conventional conception of "the problem" of workforce reform as primarily one of professional control over tasks. Holding reforms against the ideal types of Taylorism and functional flexibility is a simple, effective way the costs and benefits of workforce reform can be revealed.

  18. Incentivizing Flexibility in System Operations

    Energy Technology Data Exchange (ETDEWEB)

    Milligan, Michael [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Bloom, Aaron P [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Townsend, Aaron [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Ela, Erik [Electric Power Research Institute; Botterud, Audun [Argonne National Laboratory; Levin, Todd [Argonne National Laboratory

    2018-02-15

    Defining flexibility has been a challenge that a number of industry members and researchers have attempted to address in recent years. With increased variability and uncertainty of variable generation (VG), the resources on the system will have to be more flexible to adjust output, so that power output ranges, power ramp rates, and energy duration sustainability are sufficient to meet the needs of balancing supply with demand at various operational timescales. This chapter discusses whether existing market designs provide adequate incentives for resources to offer their flexibility into the market to meet the increased levels of variability and uncertainty introduced by VG in the short-term operational time frame. It presents a definition of flexibility and discusses how increased levels of VG require increased needs for flexibility on power systems. Following this introductory material, the chapter examines how existing market designs ensure that resources have the right incentives to provide increased flexibility, and then discusses a number of emerging market design elements that impact flexibility incentives.

  19. Flexible goal attribution in early mindreading.

    Science.gov (United States)

    Michael, John; Christensen, Wayne

    2016-03-01

    The 2-systems theory developed by Apperly and Butterfill (2009; Butterfill & Apperly, 2013) is an influential approach to explaining the success of infants and young children on implicit false-belief tasks. There is extensive empirical and theoretical work examining many aspects of this theory, but little attention has been paid to the way in which it characterizes goal attribution. We argue here that this aspect of the theory is inadequate. Butterfill and Apperly's characterization of goal attribution is designed to show how goals could be ascribed by infants without representing them as related to other psychological states, and the minimal mindreading system is supposed to operate without employing flexible semantic-executive cognitive processes. But research on infant goal attribution reveals that infants exhibit a high degree of situational awareness that is strongly suggestive of flexible semantic-executive cognitive processing, and infants appear moreover to be sensitive to interrelations between goals, preferences, and beliefs. Further, close attention to the structure of implicit mindreading tasks--for which the theory was specifically designed--indicates that flexible goal attribution is required to succeed. We conclude by suggesting 2 approaches to resolving these problems. (c) 2016 APA, all rights reserved).

  20. Discussion on the establishment of blood glucose fluctuation animal models

    OpenAIRE

    Chun-Liu Gai; Jing-Ru Zhao; Xiao-Long Chen

    2014-01-01

    AIM: To provide the experimental basis for the in vivo study of blood glucose fluctuation injury mechanism, through intraperitoneal injection of glucose to establish blood glucose fluctuation animal models and to simulate blood glucose fluctuation of patients with diabetes.METHODS: Rats were randomly divided into four groups: normal control group(NC), normal fluctuation group(NF), diabetes mellitus group(DM)and diabetes fluctuation group(DF). Diabetic models were induced through intraperitone...

  1. Role of band 3 in the erythrocyte membrane structural changes under thermal fluctuations -multi scale modeling considerations.

    Science.gov (United States)

    Pajic-Lijakovic, Ivana

    2015-12-01

    An attempt was made to discuss and connect various modeling approaches on various time and space scales which have been proposed in the literature in order to shed further light on the erythrocyte membrane rearrangement caused by the cortex-lipid bilayer coupling under thermal fluctuations. Roles of the main membrane constituents: (1) the actin-spectrin cortex, (2) the lipid bilayer, and (3) the trans membrane protein band 3 and their course-consequence relations were considered in the context of the cortex non linear stiffening and corresponding anomalous nature of energy dissipation. The fluctuations induce alternating expansion and compression of the membrane parts in order to ensure surface and volume conservation. The membrane structural changes were considered within two time regimes. The results indicate that the cortex non linear stiffening and corresponding anomalous nature of energy dissipation are related to the spectrin flexibility distribution and the rate of its changes. The spectrin flexibility varies from purely flexible to semi flexible. It is influenced by: (1) the number of band 3 molecules attached to single spectrin filaments, and (2) phosphorylation of the actin-junctions. The rate of spectrin flexibility changes depends on the band 3 molecules rearrangement.

  2. Central beta-adrenergic modulation of cognitive flexibility.

    Science.gov (United States)

    Beversdorf, David Q; White, Dawn M; Chever, Daquesha C; Hughes, John D; Bornstein, Robert A

    2002-12-20

    Situational stressors and anxiety impede performance on creativity tests requiring cognitive flexibility. Preliminary research revealed better performance on a task requiring cognitive flexibility, the anagram task, after propranolol (beta-adrenergic antagonist) than after ephedrine (beta-adrenergic agonist). However, propranolol and ephedrine have both peripheral and central beta-adrenergic effects. In order to determine whether noradrenergic modulation of cognitive flexibility is a centrally or peripherally mediated phenomenon, we compared the effects of propranolol (peripheral and central beta-blocker), nadolol (peripheral beta-blocker), and placebo on anagram task performance. Solution latency scores for each subject were compared across the drug conditions. Anagram solution latency scores after propranolol were significantly lower than after nadolol. This suggests a centrally mediated modulatory influence of the noradrenergic system on cognitive flexibility.

  3. Some fundamental aspects of fluctuations and coherence in charged-particle beams in storage rings

    International Nuclear Information System (INIS)

    Chattopadhyay, S.

    1984-01-01

    A conceptual survey and exposition is presented of some fundamental aspects of fluctuations and coherence, as well as the interplay between the two, in coasting charged-particle beams - both continuous and bunched - in storage rings. A detailed study is given of the spectral properties of the incoherent phase-space Schottky fluctuations, their propagation as waves in the beam, and the analytic complex coherent beam electromagnetic response or transfer function. The modification or distortion of these by collective interactions is examined in terms of simple regeneration mechanisms. Collective or coherent forces in the beam-storage-ring system are described by defining suitable impedance functions or propagators, and a brief discussion of the coherent collective modes and their stability is provided, including a general and rigorous description of the Nyquist stability criterion. The nature of the critical fluctuations near an instability threshold is explored. The concept of Landau damping and its connection with phase-mixing within the beam is outlined. The important connection between the incoherent fluctuations and the beam response, namely the Fluctuation-Dissipation relation, is revealed. A brief discussion is given of the information degrees of freedom, and effective temperature of the fluctuation signals. Appendices provide a short resume of some general aspects of various interactions in a charged-particle beam-environment system in a storage ring and a general introduction to kinetic theory as applied to particle beams. (orig.)

  4. Drift-Alfven waves induced optical emission fluctuations in Aditya tokamak

    International Nuclear Information System (INIS)

    Manchanda, R.; Ghosh, J.; Chattopadhyay, P. K.; Chowdhuri, M. B.; Banerjee, Santanu; Ramasubramanian, N.; Patel, Ketan M.; Kumar, Vinay; Vasu, P.; Tanna, R. L.; Paradkar, B.; Gupta, C. N.; Bhatt, S. B.; Raju, D.; Jha, R.; Atrey, P. K.; Joisa, S.; Rao, C. V. S.; Saxena, Y. C.

    2010-01-01

    In Aditya tokamak [S. B. Bhatt et al. Indian J. Pure Appl. Phys. 27, 710 (1989)], an increase in the H α and C 2+ intensity fluctuations from the edge region is observed with an increase in the magnetohydrodynamic (MHD) activity. Very small fluctuation amplitudes of H α and C 2+ intensity are observed in discharges where there is no MHD activity compared to the discharges with MHD activity. These fluctuations in the H α and C 2+ , measured by optical filter--photomultiplier tube combination--are modulated by Mirnov oscillations having a dominant peak with a common frequency ∼7-10 kHz. Further investigation reveals the presence of strong coherent fluctuations in density and floating potential at same frequency as well. These observations indicate the existence of a nonelectrostatic instability, which may be based on the coupled mode of the drift mode and the Alfven mode. The coherent density fluctuations give rise to the experimentally observed coherent H α and C 2+ intensity fluctuations.

  5. Phase Fluctuations and the Absence of Topological Defects in Photo-excited Charge Ordered Nickelate

    Energy Technology Data Exchange (ETDEWEB)

    Lee, W.S.; Chuang, Y.D.; Moore, R.G.; Zhu, Y.; Patthey, L.; Trigo, M.; Lu, D.H.; Kirchmann, P.S.; Krupin, O.; Yi, M.; Langner, M.; Huse, N.; Robinson, J.S.; Chen, Y.; Zhou, S.Y.; Coslovich, G.; Huber, B.; Reis, D.A.; Kaindl, R.A.; Schoenlein, R.W.; Doering, D.

    2012-05-15

    The dynamics of an order parameter's amplitude and phase determines the collective behaviour of novel states emerging in complex materials. Time- and momentum-resolved pump-probe spectroscopy, by virtue of measuring material properties at atomic and electronic time scales out of equilibrium, can decouple entangled degrees of freedom by visualizing their corresponding dynamics in the time domain. Here we combine time-resolved femotosecond optical and resonant X-ray diffraction measurements on charge ordered La{sub 1.75}Sr{sub 0.25}NiO{sub 4} to reveal unforeseen photoinduced phase fluctuations of the charge order parameter. Such fluctuations preserve long-range order without creating topological defects, distinct from thermal phase fluctuations near the critical temperature in equilibrium. Importantly, relaxation of the phase fluctuations is found to be an order of magnitude slower than that of the order parameter's amplitude fluctuations, and thus limits charge order recovery. This new aspect of phase fluctuations provides a more holistic view of the phase's importance in ordering phenomena of quantum matter.

  6. Effect of temperature and temperature fluctuation on thermophilic anaerobic digestion of cattle manure.

    Science.gov (United States)

    El-Mashad, Hamed M; Zeeman, Grietje; van Loon, Wilko K P; Bot, Gerard P A; Lettinga, Gatze

    2004-11-01

    The influence of temperature, 50 and 60 degrees C, at hydraulic retention times (HRTs) of 20 and 10 days, on the performance of anaerobic digestion of cow manure has been investigated in completely stirred tank reactors (CSTRs). Furthermore, the effect of both daily downward and daily upward temperature fluctuations has been studied. In the daily downward temperature fluctuation regime the temperatures of each reactor was reduced by 10 degrees C for 10 h while in the daily upward fluctuation regime the temperature of each reactor was increased 10 degrees C for 5 h. The results show that the methane production rate at 60 degrees C is lower than that at 50 degrees C at all experimental conditions of imposed HRT except when downward temperature fluctuations were applied at an HRT of 10 days. It also was found that the free ammonia concentration not only affects the acetate-utilising bacteria but also the hydrolysis and acidification process. The upward temperature fluctuation affects the maximum specific methanogenesis activity more severely as compared to imposed downward temperature fluctuations. The results clearly reveal the possibility of using available solar energy at daytime to heat up the reactor(s) without the need of heat storage during nights, especially at an operational temperature of 50 degrees C and at a 20 days HRT, and without the jeopardising of the overheating.

  7. Effect of temperature and temperature fluctuation on thermophilic anaerobic digestion of cattle manure

    Energy Technology Data Exchange (ETDEWEB)

    El-Mashad, H.M. [Mansoura University, El-Mansoura (Egypt). Faculty of Agriculture, Department of Agricultural Engineering; Zeeman, G.; Van Loon, W.K.P.; Bot, G.P.A.; Lettinga, G. [Wageningen University Agrotechnion (Netherlands). Department of Agrotechnology and Food Sciences

    2004-11-01

    The influence of temperature, 50 and 60 {sup o}C, at hydraulic retention times (HRTs) of 20 and 10 days, on the performance of anaerobic digestion of cow manure has been investigated in completely stirred tank reactors (CSTRs). Furthermore, the effect of both daily downward and daily upward temperature fluctuations has been studied. In the daily downward temperature fluctuation regime the temperatures of each reactor was reduced by 10 {sup o}C for 10 h while in the daily upward fluctuation regime the temperature of each reactor was increased 10 {sup o}C for 5 h. The results show that the methane production rate at 60 {sup o}C is lower than that at 50 {sup o}C at all experimental conditions of imposed HRT except when downward temperature fluctuations were applied at an HRT of 10 days. It also was found that the free ammonia concentration not only affects the acetate-utilising bacteria but also the hydrolysis and acidification process. The upward temperature fluctuation affects the maximum specific methanogenesis activity more severely as compared to imposed downward temperature fluctuations. The results clearly reveal the possibility of using available solar energy at daytime to heat up the reactor(s) without the need of heat storage during nights, especially at an operational temperature of 50 {sup o}C and at a 20 days HRT, and without the jeopardising of the overheating. (author)

  8. Investing in biogas: Timing, technological choice and the value of flexibility from input mix

    International Nuclear Information System (INIS)

    Di Corato, Luca; Moretto, Michele

    2011-01-01

    In a stochastic dynamic frame, we study the technology choice problem of a continuous co-digestion biogas plant where input factors are substitutes but need to be mixed together to provide output. Given any initial rule for the composition of the feedstock, we consider the possibility of revising it if economic circumstances make it profitable. Flexibility in the mix is an advantage under randomly fluctuating input costs and comes at a higher investment cost. We show that the degree of flexibility in the productive technology installed depends on the value of the option to profitably re-arrange the input mix. Such option adds value to the project in that it provides a device for hedging against fluctuations in the input relative convenience. Accounting for such value we discuss the trade-off between investment timing and profit smoothing flexibility. - Research highlights: ► We study the technology choice problem of a continuous co-digestion biogas plant where input factors are substitutes but need to be mixed together to provide output. ► We show that the degree of flexibility in the productive technology installed depends on the value of the option to profitably re-arrange the input mix. ► Such option adds value to the project in that it provides a device for hedging against fluctuations in the input relative convenience.

  9. Aggregating and Disaggregating Flexibility Objects

    DEFF Research Database (Denmark)

    Siksnys, Laurynas; Valsomatzis, Emmanouil; Hose, Katja

    2015-01-01

    In many scientific and commercial domains we encounter flexibility objects, i.e., objects with explicit flexibilities in a time and an amount dimension (e.g., energy or product amount). Applications of flexibility objects require novel and efficient techniques capable of handling large amounts...... and aiming at energy balancing during aggregation. In more detail, this paper considers the complete life cycle of flex-objects: aggregation, disaggregation, associated requirements, efficient incremental computation, and balance aggregation techniques. Extensive experiments based on real-world data from...

  10. How to resolve microsecond current fluctuations in single ion channels: The power of beta distributions

    Science.gov (United States)

    Schroeder, Indra

    2015-01-01

    Abstract A main ingredient for the understanding of structure/function correlates of ion channels is the quantitative description of single-channel gating and conductance. However, a wealth of information provided from fast current fluctuations beyond the temporal resolution of the recording system is often ignored, even though it is close to the time window accessible to molecular dynamics simulations. This kind of current fluctuations provide a special technical challenge, because individual opening/closing or blocking/unblocking events cannot be resolved, and the resulting averaging over undetected events decreases the single-channel current. Here, I briefly summarize the history of fast-current fluctuation analysis and focus on the so-called “beta distributions.” This tool exploits characteristics of current fluctuation-induced excess noise on the current amplitude histograms to reconstruct the true single-channel current and kinetic parameters. A guideline for the analysis and recent applications demonstrate that a construction of theoretical beta distributions by Markov Model simulations offers maximum flexibility as compared to analytical solutions. PMID:26368656

  11. Fluctuations and structure of amphiphilic films; Fluctuations et structure de films d`amphiphiles

    Energy Technology Data Exchange (ETDEWEB)

    Gourier, CH

    1996-07-01

    This thesis is divided in three parts.The first part exposes in a theoretical point of view, how the fluctuations spectrum of an amphiphilic film is governed by its properties and its bidimensional characteristics.The measurements of fluctuations spectra of an interface are accessible with the measurement of intensity that interface diffuses out of the specular angle, we present in the second chapter the principles of the X rays diffusion by a real interface and see how the diffuse diffusion experiments allow to determine the fluctuations spectrum of an amphiphilic film. The second part is devoted to the different experimental techniques that have allowed to realize the study of fluctuation as well as the structural study.The third part is devoted to experimental results concerning the measurements of fluctuations spectra and to the study of the structure of amphiphilic films. We show that it is possible by using an intense source of X rays (ESRF: European Synchrotron Radiation Facility) to measure the water and amphiphilic films fluctuations spectra until molecular scales. The last chapter is devoted to the structural study and film fluctuations made of di-acetylenic molecules. (N.C.)

  12. Testing of the coping flexibility hypothesis based on the dual-process theory: Relationships between coping flexibility and depressive Symptoms.

    Science.gov (United States)

    Kato, Tsukasa

    2015-12-15

    According to the dual-process theory of coping flexibility (Kato, 2012), coping flexibility is the ability to discontinue an ineffective coping strategy (i.e., evaluation coping process) and implement an alternative strategy (i.e., adaptive coping process). The coping flexibility hypothesis (CFH) proposes that the ability to engage in flexible coping is related to better psychological functioning and physical health, including less depression. I the present study, participants were 393 American Whites, 429 Australian Whites, and 496 Chinese, selected from the data pool of the 2013 Coping and Health Survey (see Kato, 2014b). They completed both the Coping Flexibility Scale (Kato, 2012), which is based on the dual-process theory of coping flexibility, and the Center for Epidemiologic Studies Depression Scale (CES-D). For all nationalities and genders, evaluation coping and adaptive coping were significantly correlated with lower levels of depressive symptoms. Structural equation modeling revealed that evaluation coping was associated with lower depressive symptoms for all nationalities and genders, whereas no significant relationships between adaptive coping and depressive symptoms were found for any nationalities. Our results partially supported that the CFH fits with the dual-process theory of coping flexibility. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  13. Magnetic fluctuations in UNi4B

    DEFF Research Database (Denmark)

    Mentink, S.A.M.; Mason, T.E.; Buyers, W.J.L.

    1997-01-01

    We investigate the magnetic fluctuation spectrum of the geometrically frustrated antiferromagnetic compound UNi4B, which partially orders below T-N = 20 K. An overdamped spin excitation is observed at the AF wave vector around 2.4 meV. Low-frequency, weakly Q-dependent inelastic scattering...

  14. State space modeling of groundwater fluctuations

    NARCIS (Netherlands)

    Berendrecht, W.L.

    2004-01-01

    Groundwater plays an important role in both urban and rural areas. It is therefore essential to monitor groundwater fluctuations. However, data that becomes available need to be analyzed further in order to extract specific information on the groundwater system. Until recently, simple linear time

  15. Fluctuations in overlapping generations economies

    DEFF Research Database (Denmark)

    Tvede, Mich

    2009-01-01

    and L less than or equal to M. The approach to existence of endogenous fluctuations is basic in the sense that the prime ingredients are the implicit function theorem and linear algebra. Moreover it is sketched how the approach can be applied to show that for an open and dense set of utility functions...

  16. Fluctuation charge effects in ionization fronts

    International Nuclear Information System (INIS)

    Arrayas, Manuel; Trueba, Jose L; Baltanas, J P

    2008-01-01

    In this paper, we study the effects of charge fluctuations on the propagation of both negative and positive ionization fronts in streamer discharges. We show that fronts accelerate when random charge creation events are present. This effect might play a similar role to photoionization in order to make the front move faster

  17. Fluctuation charge effects in ionization fronts

    Energy Technology Data Exchange (ETDEWEB)

    Arrayas, Manuel; Trueba, Jose L [Area de Electromagnetismo, Universidad Rey Juan Carlos, Camino del Molino s/n, 28943 Fuenlabrada, Madrid (Spain); Baltanas, J P [Departamento de Fisica Aplicada II, Universidad de Sevilla, Av. Reina Mercedes 2, 41012 Sevilla (Spain)

    2008-05-21

    In this paper, we study the effects of charge fluctuations on the propagation of both negative and positive ionization fronts in streamer discharges. We show that fronts accelerate when random charge creation events are present. This effect might play a similar role to photoionization in order to make the front move faster.

  18. Hole pairing induced by antiferromagnetic spin fluctuations

    International Nuclear Information System (INIS)

    Su, Z.B.; Yu Lu; Dong, J.M.; Tosatti, E.

    1987-08-01

    The effective interaction induced by antiferromagnetic spin fluctuations is considered in the random phase approximation in the context of the recently discovered high T c oxide superconductors. This effective attraction favours a triplet pairing of holes. The implications of such pairing mechanism are discussed in connection with the current experimental observations. (author). 30 refs, 2 figs

  19. Zeta function methods and quantum fluctuations

    International Nuclear Information System (INIS)

    Elizalde, Emilio

    2008-01-01

    A review of some recent advances in zeta function techniques is given, in problems of pure mathematical nature but also as applied to the computation of quantum vacuum fluctuations in different field theories, and specially with a view to cosmological applications

  20. Deriving GENERIC from a generalized fluctuation symmetry

    NARCIS (Netherlands)

    Kraaij, R.; Lazarescu, A.; Maes, C.; Peletier, M.A.

    2018-01-01

    Much of the structure of macroscopic evolution equations for relaxation to equilibrium can be derived from symmetries in the dynamical fluctuations around the most typical trajectory. For example, detailed balance as expressed in terms of the Lagrangian for the path-space action leads to gradient

  1. On statistical fluctuations in the dibaryon spectra

    International Nuclear Information System (INIS)

    Bazhanskij, I.I.; Luk'yanov, V.K.; Reznik, B.L.; Titov, A.I.

    1988-01-01

    The aim of this report is to show, that idea about statistical nature of dibaryon resonances corresponds to the present experimental data. Condition for cross section fluctuation occurrence is linked with value of decay width for isolated dibaryon in nucleon channel. Γ in terms of dibaryon potential quark model and q 6 → NN dibaryon decay for q 6 state with S 6 orbital symmetry and (S=I, I=0) deuteron quantum numbers are calculated as an example. np → ppπ - , dp → ppn and elastic pp-scattering are considered and distributions of cross sections and correlation functions obtained from these reactions are presented to investigate cross section fluctuations in spectra of effective masses of two-nucleon systems. Supposition about fluctuation pattern does not contradict the experiment. Curves, calculated with x l α < or approx. 0.05 partial amplitude parameter and full width of Γ < or approx. 20 MeV dibaryon resonances comply to the present experiment best. Fluctuation peculiarities -peaks in cross sections have approximately the same energy width (Γ ∼ 15-20 MeV) as the observed narrow peak in effective mass spectra of some reactions. 16 refs.; 3 figs

  2. Fluctuations in models with primordial inflation

    International Nuclear Information System (INIS)

    Kahn, R.; Brandenberger, R.

    1984-01-01

    The recently proposed general framework for calculating the growth of primordial energy density fluctuations in cosmological models is applied to two models of phenomenological interest in which the cosmological evolution differs crucially from that in new inflationary universe models. Both in a model of primordial supersymmetric inflation and in Linde's proposal of chaotic inflation we verify the conjectured results. (orig.)

  3. Correlations and fluctuations '98. Collected abstracts

    International Nuclear Information System (INIS)

    Csoergoe, T.; Hegyi, S.; Hwa, R.C.; Jancso, G.

    1998-01-01

    The proceedings of the 8. International workshop on multiparticle production contains the abstracts of papers on various topics of correlations and fluctuations. Hydrodynamic models, Bose-Einstein correlations, hadron-hadron interactions, heavy ion reactions are discussed in detail. 54 items are indexed separately for the INIS database. (K.A.)

  4. Relationship among phenotypic plasticity, phenotypic fluctuations ...

    Indian Academy of Sciences (India)

    Prakash

    changes produced by mutations. On the other hand, the .... fluorescence in bacteria and checked a possible relationship between evolution speed ... at each generation, and the fluctuation by the variance of ..... that by Eigen. 4. Microscopic approach: Gene regulation network ..... Formulation; Biopolymers 20 1013. Alon U ...

  5. Macroeconomic fluctuations and mortality in postwar Japan.

    Science.gov (United States)

    Granados, José A Tapia

    2008-05-01

    Recent research has shown that after long-term declining trends are excluded, mortality rates in industrial countries tend to rise in economic expansions and fall in economic recessions. In the present work, co-movements between economic fluctuations and mortality changes in postwar Japan are investigated by analyzing time series of mortality rates and eight economic indicators. To eliminate spurious associations attributable to trends, series are detrended either via Hodrick-Prescott filtering or through differencing. As previously found in other industrial economies, general mortality and age-specific death rates in Japan tend to increase in expansions and drop in recessions, for both males and females. The effect, which is slightly stronger for males, is particularly noticeable in those aged 45-64. Deaths attributed to heart disease, pneumonia, accidents, liver disease, and senility--making up about 41% of total mortality--tend to fluctuate procyclically, increasing in expansions. Suicides, as well as deaths attributable to diabetes and hypertensive disease, make up about 4% of total mortality and fluctuate countercyclically, increasing in recessions. Deaths attributed to other causes, making up about half of total deaths, don't show a clearly defined relationship with the fluctuations of the economy.

  6. Motion sensing using WLAN signal fluctuations

    NARCIS (Netherlands)

    Kavitha Muthukrishnan, K.; Lijding, M.E.M.; Meratnia, Nirvana; Havinga, Paul J.M.

    2006-01-01

    The ability to infer the motion of the user has previously been possible only with the usage of additional hardware. In this paper we show how motion sensing can be obtained just by observing the WLAN radio’s signal strength and its fluctuations. For the first time, we have analyzed the signal

  7. Thermal fluctuation problems encountered in LMFRs

    International Nuclear Information System (INIS)

    Gelineau, O.; Sperandio, M.; Martin, P.; Ricard, J.B.; Martin, L.; Bougault, A.

    1994-01-01

    One of the most significant problems of LMFBRs deals with thermal fluctuations. The main reason is that LMFBRs operate with sodium coolant at very different temperatures which leads to the existence of several areas of transition between hot and cold sodium. These transitions areas which are the critical points, maybe found in the reactor block as well as in the secondary and auxiliary loops. The characteristics of these thermal fluctuations are not easy to quantify because of their complex (random) behaviour, and often demand the use of thermalhydraulic mock-up tests. A good knowledge of these phenomena is essential because of the potential high level of damage they can induce on structures. Two typical thermal fluctuation problems encountered on operation reactors are described. They were not originally anticipated at the design stage of the former Phenix and the latter Superphenix reactors. Description and the analyses performed to describe the damaging process are explained. A well known thermal fluctuation problem is presented. It is pointed out how the feedback from the damages observed on operating reactors is used to prevent the components from any high cycle fatigue

  8. Correlation anlaysis of plasma fluctuation signals

    International Nuclear Information System (INIS)

    Wan Baonian; Wang Zhaoshen

    1987-01-01

    The application of correlation analysis to identify waves and instabilities in plasma is presented. First, the principle of correlation analysis and its application to diagnose plasma fluctuation signals are given. Then, the data acqusition system, application program and calibration method are described. Finally, experimental results from a mirror device are given

  9. Multiplicity distributions and charged-neutral fluctuations

    Indian Academy of Sciences (India)

    from the WA98 experiment at the CERN-SPS. For a thermalized .... light nuclei are well described in the framework of wounded nuclear model [21]. In this ... state rescattering, where the incoming particles loose their memory and every participant ..... In order to compare these fluctuations at different scales in the same level,.

  10. Advantages of storage in a fluctuating environment.

    NARCIS (Netherlands)

    Kooi, B.W.; Troost, T.A.

    2006-01-01

    We will elaborate the evolutionary course of an ecosystem consisting of a population in a chemostat environment with periodically fluctuating nutrient supply. The organisms that make up the population consist of structural biomass and energy storage compartments. In a constant chemostat environment

  11. Origin of Pressure Fluctuations in Fluidized Beds

    Czech Academy of Sciences Publication Activity Database

    Punčochář, Miroslav; Drahoš, Jiří

    2005-01-01

    Roč. 60, č. 5 (2005), s. 1193-1197 ISSN 0009-2509 Institutional research plan: CEZ:AV0Z40720504 Keywords : fluidization * pressure fluctuations * bubbles Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 1.735, year: 2005

  12. Joint probability distributions and fluctuation theorems

    International Nuclear Information System (INIS)

    García-García, Reinaldo; Kolton, Alejandro B; Domínguez, Daniel; Lecomte, Vivien

    2012-01-01

    We derive various exact results for Markovian systems that spontaneously relax to a non-equilibrium steady state by using joint probability distribution symmetries of different entropy production decompositions. The analytical approach is applied to diverse problems such as the description of the fluctuations induced by experimental errors, for unveiling symmetries of correlation functions appearing in fluctuation–dissipation relations recently generalized to non-equilibrium steady states, and also for mapping averages between different trajectory-based dynamical ensembles. Many known fluctuation theorems arise as special instances of our approach for particular twofold decompositions of the total entropy production. As a complement, we also briefly review and synthesize the variety of fluctuation theorems applying to stochastic dynamics of both continuous systems described by a Langevin dynamics and discrete systems obeying a Markov dynamics, emphasizing how these results emerge from distinct symmetries of the dynamical entropy of the trajectory followed by the system. For Langevin dynamics, we embed the 'dual dynamics' with a physical meaning, and for Markov systems we show how the fluctuation theorems translate into symmetries of modified evolution operators

  13. Collateral fluctuations in a monetary economy

    NARCIS (Netherlands)

    Ferraris, L.; Watanabe, M.

    2011-01-01

    This paper studies economy-wide fluctuations that occur endogenously in the presence of monetary and real assets. Using a standard monetary search model, we consider an economy in which agents can increase consumption, over and above what their liquid monetary asset holdings would allow, pledging

  14. Collective spin fluctuations in diluted magnetic semiconductors

    Czech Academy of Sciences Publication Activity Database

    König, J.; Schliemann, J.; Jungwirth, Tomáš; MacDonald, A. H.

    2002-01-01

    Roč. 12, - (2002), s. 379-382 ISSN 1386-9477 Institutional research plan: CEZ:AV0Z1010914 Keywords : spin fluctuation * magnetic semiconductors Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.107, year: 2002

  15. Surface Fluctuation Scattering using Grating Heterodyne Spectroscopy

    DEFF Research Database (Denmark)

    Edwards, R. V.; Sirohi, R. S.; Mann, J. A.

    1982-01-01

    Heterodyne photon spectroscopy is used for the study of the viscoelastic properties of the liquid interface by studying light scattered from thermally generated surface fluctuations. A theory of a heterodyne apparatus based on a grating is presented, and the heterodyne condition is given in terms...

  16. Electron quantum interferences and universal conductance fluctuations

    International Nuclear Information System (INIS)

    Benoit, A.; Pichard, J.L.

    1988-05-01

    Quantum interferences yield corrections to the classical ohmic behaviour predicted by Boltzmann theory in electronic transport: for instance the well-known ''weak localization'' effects. Furthermore, very recently, quantum interference effects have been proved to be responsible for statistically different phenomena, associated with Universal Conductance Fluctuations and observed on very small devices [fr

  17. temperature fluctuation inside inert atmosphere silos

    African Journals Online (AJOL)

    ... the two silos for twenty-eight (28) months of storage were recorded in order to monitor temperature fluctuation at different sections inside the inert atmosphere silos loaded with two varieties of wheat namely LACRIWHT-2 (Cettia) and LACRIWHT-4 (Atilla-Gan-Atilla) from Lake Chad Research Institute, Maiduguri, Nigeria.

  18. Double-valence-fluctuating molecules and superconductivity

    International Nuclear Information System (INIS)

    Hirsch, J.E.; Scalapino, D.J.

    1985-01-01

    We discuss the possibility of ''double-valence-fluctuating'' molecules, having two ground-state configurations differing by two electrons. We propose a possible realization of such a molecule, and experimental ways to look for it. We argue that a weakly coupled array of such molecules should give rise to a strong-coupling Shafroth-Blatt-Butler superconductor, with a high transition temperature

  19. Phase space dynamics and collective variable fluctuations

    International Nuclear Information System (INIS)

    Benhassine, B.; Farine, M.; Idier, D.; Remaud, B.; Sebille, F.; Schuck, P.

    1995-01-01

    A dynamical study of collective variable fluctuations in heavy ion reactions is performed within the framework of the Boltzmann-Langevin theory. A general method to extract dispersions on collective variables from numerical simulations based on test particles models is presented and its validity is checked by comparison with analytical equilibrium results. (authors)

  20. Phase space dynamics and collective variable fluctuations

    Energy Technology Data Exchange (ETDEWEB)

    Benhassine, B.; Farine, M.; Idier, D.; Remaud, B.; Sebille, F. [Laboratoire de Physique Nucleaire de Nantes, 44 (France); Schuck, P. [Institut des Sciences Nucleaires, 38 - Grenoble (France)

    1995-12-31

    A dynamical study of collective variable fluctuations in heavy ion reactions is performed within the framework of the Boltzmann-Langevin theory. A general method to extract dispersions on collective variables from numerical simulations based on test particles models is presented and its validity is checked by comparison with analytical equilibrium results. (authors) 10 refs.

  1. Event-by-event fluctuations at SPS

    CERN Document Server

    Appelshauser, Harald; Adamova, D.; Agakichiev, G.; Belaga, V.; Braun-Munzinger, P.; Castillo, A.; Cherlin, A.; Damjanovic, S.; Dietel, T.; Dietrich, L.; Drees, A.; Esumi, S.I.; Filimonov, K.; Fomenko, K.; Fraenkel, Z.; Garabatos, C.; Glassel, P.; Hering, G.; Holeczek, J.; Kushpil, V.; Lenkeit, B.; Ludolphs, W.; Maas, A.; Marn, A.; Milosevic, J.; Milov, A.; Miskowiec, D.; Panebrattsev, Yu.; Petchenova, O.; Petracek, V.; Pfeiffer, A.; Rak, J.; Ravinovich, I.; Rehak, P.; Schmitz, W.; Schukraft, J.; Sedykh, S.; Shimansky, S.; Slvova, J.; Stachel, J.; Sumbera, M.; Tilsner, H.; Tserruya, Itzhak; Wessels, J.P.; Wienold, T.; Windelband, B.; Wurm, J.P.; Xie, W.; Yurevich, S.; Yurevich, V.; Appelshauser, Harald; Sako, Hiro

    2005-01-01

    Results on event-by-event fluctuations of the mean transverse momentum and net charge in Pb-Au collisions, measured by the CERES Collaboration at CERN-SPS, are presented. We discuss the centrality and beam energy dependence and compare our data to cascade calculations.

  2. Fluctuation scaling, Taylor's law, and crime.

    Directory of Open Access Journals (Sweden)

    Quentin S Hanley

    Full Text Available Fluctuation scaling relationships have been observed in a wide range of processes ranging from internet router traffic to measles cases. Taylor's law is one such scaling relationship and has been widely applied in ecology to understand communities including trees, birds, human populations, and insects. We show that monthly crime reports in the UK show complex fluctuation scaling which can be approximated by Taylor's law relationships corresponding to local policing neighborhoods and larger regional and countrywide scales. Regression models applied to local scale data from Derbyshire and Nottinghamshire found that different categories of crime exhibited different scaling exponents with no significant difference between the two regions. On this scale, violence reports were close to a Poisson distribution (α = 1.057 ± 0.026 while burglary exhibited a greater exponent (α = 1.292 ± 0.029 indicative of temporal clustering. These two regions exhibited significantly different pre-exponential factors for the categories of anti-social behavior and burglary indicating that local variations in crime reports can be assessed using fluctuation scaling methods. At regional and countrywide scales, all categories exhibited scaling behavior indicative of temporal clustering evidenced by Taylor's law exponents from 1.43 ± 0.12 (Drugs to 2.094 ± 0081 (Other Crimes. Investigating crime behavior via fluctuation scaling gives insight beyond that of raw numbers and is unique in reporting on all processes contributing to the observed variance and is either robust to or exhibits signs of many types of data manipulation.

  3. Fluctuation scaling, Taylor's law, and crime.

    Science.gov (United States)

    Hanley, Quentin S; Khatun, Suniya; Yosef, Amal; Dyer, Rachel-May

    2014-01-01

    Fluctuation scaling relationships have been observed in a wide range of processes ranging from internet router traffic to measles cases. Taylor's law is one such scaling relationship and has been widely applied in ecology to understand communities including trees, birds, human populations, and insects. We show that monthly crime reports in the UK show complex fluctuation scaling which can be approximated by Taylor's law relationships corresponding to local policing neighborhoods and larger regional and countrywide scales. Regression models applied to local scale data from Derbyshire and Nottinghamshire found that different categories of crime exhibited different scaling exponents with no significant difference between the two regions. On this scale, violence reports were close to a Poisson distribution (α = 1.057 ± 0.026) while burglary exhibited a greater exponent (α = 1.292 ± 0.029) indicative of temporal clustering. These two regions exhibited significantly different pre-exponential factors for the categories of anti-social behavior and burglary indicating that local variations in crime reports can be assessed using fluctuation scaling methods. At regional and countrywide scales, all categories exhibited scaling behavior indicative of temporal clustering evidenced by Taylor's law exponents from 1.43 ± 0.12 (Drugs) to 2.094 ± 0081 (Other Crimes). Investigating crime behavior via fluctuation scaling gives insight beyond that of raw numbers and is unique in reporting on all processes contributing to the observed variance and is either robust to or exhibits signs of many types of data manipulation.

  4. Critical fluctuations in cortical models near instability

    NARCIS (Netherlands)

    Aburn, M.J.; Holmes, C.A.; Roberts, J.A.; Boonstra, T.W.; Breakspear, M.

    2012-01-01

    Computational studies often proceed from the premise that cortical dynamics operate in a linearly stable domain, where fluctuations dissipate quickly and show only short memory. Studies of human electroencephalography (EEG), however, have shown significant autocorrelation at time lags on the scale

  5. Fluctuation Solution Theory Properties from Molecular Simulation

    DEFF Research Database (Denmark)

    Abildskov, Jens; Wedberg, R.; O’Connell, John P.

    2013-01-01

    The thermodynamic properties obtained in the Fluctuation Solution Theory are based on spatial integrals of molecular TCFs between component pairs in the mixture. Molecular simulation, via either MD or MC calculations, can yield these correlation functions for model inter- and intramolecular...

  6. Analytical theory of intensity fluctuations in SASE

    Energy Technology Data Exchange (ETDEWEB)

    Yu, L.H.; Krinsky, S. [Brookhaven National Lab., Upton, NY (United States). National Synchrotron Light Source

    1997-07-01

    Recent advances in SASE experiments stimulate interest in quantitative comparison of measurements with theory. Extending the previous analysis of the SASE intensity in guided modes, the authors provide an analytical description of the intensity fluctuations by calculating intensity correlation functions in the frequency domain. Comparison of the results with experiment yields new insight into the SASE process.

  7. Radial Variations of Outward and Inward Alfvénic Fluctuations Based on Ulysses Observations

    Science.gov (United States)

    Yang, L.; Lee, L. C.; Li, J. P.; Luo, Q. Y.; Kuo, C. L.; Shi, J. K.; Wu, D. J.

    2017-12-01

    Ulysses magnetic and plasma data are used to study hourly scale Alfvénic fluctuations in the solar polar wind. The calculated energy ratio {R}{vA}2(cal) of inward to outward Alfvén waves is obtained from the observed Walén slope through an analytical expression, and the observed {R}{vA}2(obs) is based on a direct decomposition of original Alfvénic fluctuations into outward- and inward-propagating Alfvén waves. The radial variation of {R}{vA}2(cal) shows a monotonically increasing trend with heliocentric distance r, implying the increasing local generation or contribution of inward Alfvén waves. The contribution is also shown by the radial increase in the occurrence of dominant inward fluctuations. We further pointed out a higher occurrence (˜ 83 % of a day in average) of dominant outward Alfvénic fluctuations in the solar wind than previously estimated. Since {R}{vA}2(cal) is more accurate than {R}{vA}2(obs) in the measurement of the energy ratio for dominant outward fluctuations, the values of {R}{vA}2(cal) in our results are likely more realistic in the solar wind than those previously estimated as well as {R}{vA}2(obs) in our results. The duration ratio R T of dominant inward to all Alfvénic fluctuations increases monotonically with r, and is about two or more times that from Voyager 2 observations at r≥slant 4 {au}. These results reveal new qualitative and quantitative features of Alfvénic fluctuations therein compared with previous studies and put constraints on modeling the variation of solar wind fluctuations.

  8. Measurement of turbulent electron temperature fluctuations on the ASDEX Upgrade tokamak using correlated electron cyclotron emission

    Energy Technology Data Exchange (ETDEWEB)

    Freethy, S. J., E-mail: simon.freethy@ipp.mpg.de [Max Planck Institute for Plasma Physics, 85748 Garching (Germany); Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Conway, G. D.; Happel, T.; Köhn, A. [Max Planck Institute for Plasma Physics, 85748 Garching (Germany); Classen, I.; Vanovac, B. [FOM Institute DIFFER, 5612 AJ Eindhoven (Netherlands); Creely, A. J.; White, A. E. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2016-11-15

    Turbulent temperature fluctuations are measured on the ASDEX Upgrade tokamak using pairs of closely spaced, narrow-band heterodyne radiometer channels and a standard correlation technique. The pre-detection spacing and bandwidth of the radiometer channel pairs is chosen such that they are physically separated less than a turbulent correlation length, but do not overlap. The radiometer has 4 fixed filter frequency channels and two tunable filter channels for added flexibility in the measurement position. Relative temperature fluctuation amplitudes are observed in a helium plasma to be δT/T = (0.76 ± 0.02)%, (0.67 ± 0.02)%, and (0.59 ± 0.03)% at normalised toroidal flux radius of ρ{sub tor} = 0.82, 0.75, and 0.68, respectively.

  9. One-point fluctuation analysis of the high-energy neutrino sky

    DEFF Research Database (Denmark)

    Feyereisen, Michael R.; Tamborra, Irene; Ando, Shin'ichiro

    2017-01-01

    We perform the first one-point fluctuation analysis of the high-energy neutrino sky. This method reveals itself to be especially suited to contemporary neutrino data, as it allows to study the properties of the astrophysical components of the high-energy flux detected by the IceCube telescope, even...

  10. A test particle motion in the Kerr field with fluctuating perturbations

    International Nuclear Information System (INIS)

    Zhuk, I.T.; Piragas, K.A.

    1982-01-01

    Motion of a stochastic test particle in the Kerr black hole field in the approximation of Brown interaction is considered. Probability distribution of orbit position by the latitude angle is revealed, bifurcation values of their parameters are determined. Fluctuating instability of orbits characteristic of critical modes of motion is investigated, properties of some statistical characteristics of the system are identified

  11. Geometric coupling effects on the bifurcations of a flexible rotor response in active magnetic bearings

    International Nuclear Information System (INIS)

    Inayat-Hussain, Jawaid I.

    2009-01-01

    This work reports on a numerical investigation on the bifurcations of a flexible rotor response in active magnetic bearings taking into account the nonlinearity due to the geometric coupling of the magnetic actuators as well as that arising from the actuator forces that are nonlinear function of the coil current and the air gap. For the values of design and operating parameters of the rotor-bearing system investigated in this work, numerical results showed that the response of the rotor was always synchronous when the values of the geometric coupling parameter α were small. For relatively larger values of α, however, the response of the rotor displayed a rich variety of nonlinear dynamical phenomena including sub-synchronous vibrations of periods-2, -3, -6, -9, and -17, quasi-periodicity and chaos. Numerical results further revealed the co-existence of multiple attractors within certain ranges of the speed parameter Ω. In practical rotating machinery supported by active magnetic bearings, the possibility of synchronous rotor response to become non-synchronous or even chaotic cannot be ignored as preloads, fluid forces or other external excitation forces may cause the rotor's initial conditions to move from one basin of attraction to another. Non-synchronous and chaotic vibrations should be avoided as they induce fluctuating stresses that may lead to premature failure of the machinery's main components.

  12. Non-Redfield, nutrient synergy and flexible internal elemental stoichiometry in a marine bacterium.

    Science.gov (United States)

    Trautwein, Kathleen; Feenders, Christoph; Hulsch, Reiner; Ruppersberg, Hanna S; Strijkstra, Annemieke; Kant, Mirjam; Vagts, Jannes; Wünsch, Daniel; Michalke, Bernhard; Maczka, Michael; Schulz, Stefan; Hillebrand, Helmut; Blasius, Bernd; Rabus, Ralf

    2017-05-01

    The stoichiometric constraints of algal growth are well understood, whereas there is less knowledge for heterotrophic bacterioplankton. Growth of the marine bacterium Phaeobacter inhibens DSM 17395, belonging to the globally distributed Roseobacter group, was studied across a wide concentration range of NH4+ and PO43-. The unique dataset covers 415 different concentration pairs, corresponding to 207 different molar N:P ratios (from 10-2 to 105). Maximal growth (by growth rate and biomass yield) was observed within a restricted concentration range at N:P ratios (∼50-120) markedly above Redfield. Experimentally determined growth parameters deviated to a large part from model predictions based on Liebig's law of the minimum, thus implicating synergistic co-limitation due to biochemical dependence of resources. Internal elemental ratios of P. inhibens varied with external nutrient supply within physiological constraints, thus adding to the growing evidence that aquatic bacteria can be flexible in their internal elemental composition. Taken together, the findings reported here revealed that P. inhibens is well adapted to fluctuating availability of inorganic N and P, expected to occur in its natural habitat (e.g. colonized algae, coastal areas). Moreover, this study suggests that elemental variability in bacterioplankton needs to be considered in the ecological stoichiometry of the oceans. © FEMS 2017.

  13. Flexible Thermoelectric Generators on Silicon Fabric

    KAUST Repository

    Sevilla, Galo T.

    2012-01-01

    In this work, the development of a Thermoelectric Generator on Flexible Silicon Fabric is explored to extend silicon electronics for flexible platforms. Low cost, easily deployable plastic based flexible electronics are of great interest for smart

  14. Fluid Fuel Fluctuations in the Spherical Tank

    Directory of Open Access Journals (Sweden)

    H. D. Nguyen

    2014-01-01

    Full Text Available Many authors tried to solve a task concerning small fluctuations of the incompressible ideal liquid, which partially fills a stationary tank of any shape. There is a long list of references to this subject. The article presents a task solution on own fluctuations of liquid in spherical capacity, with boundary conditions on a free surface and a surface with a resistance – drain surface. Relevance of problem consists in assessment of influence of intra tank devices (measuring, intaking, damping devices, etc. on the liquid fuel fluctuations. The special attention is paid to finding the own values and frequencies of the equations of disturbed flow fluctuations with dissipation available on the boundary surfaces. In contrast to the previous examples, the lowering speed and the free surface area at undisturbed state are variable.The article also considers a variation formulation of the auxiliary boundary tasks. In solution of variation tasks, the attached Legendre's functions were used as coordinate functions. Further, after substitution of the variation tasks solution in the boundary conditions and the subsequent mathematical operations the characteristic equation was obtained. To obtain solutions of the cubic characteristic equation Cardano formulas were used. The article also considers the task on the own motions of liquid filling a capacity between two concentric spheres and flowing out via the intake in case there is a free surface. Reliability of the obtained numerical results is confirmed by comparison with calculation results of frequencies resulting from solutions of a task on the own fluctuations of liquid in the spherical capacity with the constant depth of liquid. All numerical calculations were performed using the Matlab environment.

  15. Critical fluctuations in cortical models near instability

    Directory of Open Access Journals (Sweden)

    Matthew J. Aburn

    2012-08-01

    Full Text Available Computational studies often proceed from the premise that cortical dynamics operate in a linearly stable domain, where fluctuations dissipate quickly and show only short memory. Studies of human EEG, however, have shown significant autocorrelation at time lags on the scale of minutes, indicating the need to consider regimes where nonlinearities influence the dynamics. Statistical properties such as increased autocorrelation length, increased variance, power-law scaling and bistable switching have been suggested as generic indicators of the approach to bifurcation in nonlinear dynamical systems. We study temporal fluctuations in a widely-employed computational model (the Jansen-Rit model of cortical activity, examining the statistical signatures that accompany bifurcations. Approaching supercritical Hopf bifurcations through tuning of the background excitatory input, we find a dramatic increase in the autocorrelation length that depends sensitively on the direction in phase space of the input fluctuations and hence on which neuronal subpopulation is stochastically perturbed. Similar dependence on the input direction is found in the distribution of fluctuation size and duration, which show power law scaling that extends over four orders of magnitude at the Hopf bifurcation. We conjecture that the alignment in phase space between the input noise vector and the center manifold of the Hopf bifurcation is directly linked to these changes. These results are consistent with the possibility of statistical indicators of linear instability being detectable in real EEG time series. However, even in a simple cortical model, we find that these indicators may not necessarily be visible even when bifurcations are present because their expression can depend sensitively on the neuronal pathway of incoming fluctuations.

  16. Flexibility of trunnion piping elbows

    International Nuclear Information System (INIS)

    Lewis, G.D.; Chao, Y.J.

    1987-01-01

    Flexibility factors and stress indices for piping component such as straight pipe, elbows, butt-welding tees, branch connections, and butt-welding reducers are contained in the code, but many of the less common piping components, like the trunnion elbow, do not have flexibility factors or stress indices defined. The purpose of this paper is to identify the in-plane and out-of-plane flexibility factors in accordance with code procedures for welded trunnions attached to the tangent centerlines of long radius elbows. This work utilized the finite element method as applicable to plates and shells for calculating the relative rotations of the trunnion elbow-ends for in-plane and out-of-plane elbow moment loadings. These rotations are used to derive the corresponding in-plane and out-of-plane flexibility factors. (orig./GL)

  17. Distributed flexibility in inertial swimmers

    Science.gov (United States)

    Floryan, Daniel; Rowley, Clarence W.; Smits, Alexander J.

    2017-11-01

    To achieve fast and efficient swimming, the flexibility of the propulsive surfaces is an important feature. To better understand the effects of distributed flexibility (either through inhomogeneous material properties, varying geometry, or both) we consider the coupled solid and fluid mechanics of the problem. Here, we develop a simplified model of a flexible swimmer, using Euler-Bernoulli theory to describe the solid, Theodorsen's theory to describe the fluid, and a Blasius boundary layer to incorporate viscous effects. Our primary aims are to understand how distributed flexibility affects the thrust production and efficiency of a swimmer with imposed motion at its leading edge. In particular, we examine the modal shapes of the swimmer to gain physical insight into the observed trends. Supported under ONR MURI Grant N00014-14-1-0533, Program Manager Robert Brizzolara.

  18. Incorporation of protein flexibility and conformational energy penalties in docking screens to improve ligand discovery

    Science.gov (United States)

    Fischer, Marcus; Coleman, Ryan G.; Fraser, James S.; Shoichet, Brian K.

    2014-07-01

    Proteins fluctuate between alternative conformations, which presents a challenge for ligand discovery because such flexibility is difficult to treat computationally owing to problems with conformational sampling and energy weighting. Here we describe a flexible docking method that samples and weights protein conformations using experimentally derived conformations as a guide. The crystallographically refined occupancies of these conformations, which are observable in an apo receptor structure, define energy penalties for docking. In a large prospective library screen, we identified new ligands that target specific receptor conformations of a cavity in cytochrome c peroxidase, and we confirm both ligand pose and associated receptor conformation predictions by crystallography. The inclusion of receptor flexibility led to ligands with new chemotypes and physical properties. By exploiting experimental measures of loop and side-chain flexibility, this method can be extended to the discovery of new ligands for hundreds of targets in the Protein Data Bank for which similar experimental information is available.

  19. Workplace flexibility across the lifespan

    OpenAIRE

    Bal, Pieter; Jansen, Paul G W

    2016-01-01

    As demographic changes impact the workplace, governments, organizations and workers arelooking for ways to sustain optimal working lives at higher ages. Workplace flexibility has beenintroduced as a potential way workers can have more satisfying working lives until theirretirement ages. This paper presents a critical review of the literature on workplace flexibilityacross the lifespan. It discusses how flexibility has been conceptualized across differentdisciplines, and postulates a definitio...

  20. Flexible packaging for PV modules

    Science.gov (United States)

    Dhere, Neelkanth G.

    2008-08-01

    Economic, flexible packages that provide needed level of protection to organic and some other PV cells over >25-years have not yet been developed. However, flexible packaging is essential in niche large-scale applications. Typical configuration used in flexible photovoltaic (PV) module packaging is transparent frontsheet/encapsulant/PV cells/flexible substrate. Besides flexibility of various components, the solder bonds should also be flexible and resistant to fatigue due to cyclic loading. Flexible front sheets should provide optical transparency, mechanical protection, scratch resistance, dielectric isolation, water resistance, UV stability and adhesion to encapsulant. Examples are Tefzel, Tedlar and Silicone. Dirt can get embedded in soft layers such as silicone and obscure light. Water vapor transmittance rate (WVTR) of polymer films used in the food packaging industry as moisture barriers are ~0.05 g/(m2.day) under ambient conditions. In comparison, light emitting diodes employ packaging components that have WVTR of ~10-6 g/(m2.day). WVTR of polymer sheets can be improved by coating them with dense inorganic/organic multilayers. Ethylene vinyl acetate, an amorphous copolymer used predominantly by the PV industry has very high O2 and H2O diffusivity. Quaternary carbon chains (such as acetate) in a polymer lead to cleavage and loss of adhesional strength at relatively low exposures. Reactivity of PV module components increases in presence of O2 and H2O. Adhesional strength degrades due to the breakdown of structure of polymer by reactive, free radicals formed by high-energy radiation. Free radical formation in polymers is reduced when the aromatic rings are attached at regular intervals. This paper will review flexible packaging for PV modules.

  1. Flexible forms of working hours

    OpenAIRE

    Knapp, Viktor

    2017-01-01

    66 Abstract - Flexible forms of working hours This diploma thesis deals with the flexible forms of working hours and its goal is to describe this issue in intelligible and comprehensive way. It is being very interesting and current theme which is to a great extent not subject to direct legal regulations and provides its contracting parties with a big amount of freedom of contract. This fact assists in bigger flexibilization of labour market and represents a significant instrument in the fight...

  2. Nonlinear dynamics of mushy layers induced by external stochastic fluctuations.

    Science.gov (United States)

    Alexandrov, Dmitri V; Bashkirtseva, Irina A; Ryashko, Lev B

    2018-02-28

    The time-dependent process of directional crystallization in the presence of a mushy layer is considered with allowance for arbitrary fluctuations in the atmospheric temperature and friction velocity. A nonlinear set of mushy layer equations and boundary conditions is solved analytically when the heat and mass fluxes at the boundary between the mushy layer and liquid phase are induced by turbulent motion in the liquid and, as a result, have the corresponding convective form. Namely, the 'solid phase-mushy layer' and 'mushy layer-liquid phase' phase transition boundaries as well as the solid fraction, temperature and concentration (salinity) distributions are found. If the atmospheric temperature and friction velocity are constant, the analytical solution takes a parametric form. In the more common case when they represent arbitrary functions of time, the analytical solution is given by means of the standard Cauchy problem. The deterministic and stochastic behaviour of the phase transition process is analysed on the basis of the obtained analytical solutions. In the case of stochastic fluctuations in the atmospheric temperature and friction velocity, the phase transition interfaces (mushy layer boundaries) move faster than in the deterministic case. A cumulative effect of these noise contributions is revealed as well. In other words, when the atmospheric temperature and friction velocity fluctuate simultaneously due to the influence of different external processes and phenomena, the phase transition boundaries move even faster. This article is part of the theme issue 'From atomistic interfaces to dendritic patterns'.This article is part of the theme issue 'From atomistic interfaces to dendritic patterns'. © 2018 The Author(s).

  3. Developmental constraints on behavioural flexibility.

    Science.gov (United States)

    Holekamp, Kay E; Swanson, Eli M; Van Meter, Page E

    2013-05-19

    We suggest that variation in mammalian behavioural flexibility not accounted for by current socioecological models may be explained in part by developmental constraints. From our own work, we provide examples of constraints affecting variation in behavioural flexibility, not only among individuals, but also among species and higher taxonomic units. We first implicate organizational maternal effects of androgens in shaping individual differences in aggressive behaviour emitted by female spotted hyaenas throughout the lifespan. We then compare carnivores and primates with respect to their locomotor and craniofacial adaptations. We inquire whether antagonistic selection pressures on the skull might impose differential functional constraints on evolvability of skulls and brains in these two orders, thus ultimately affecting behavioural flexibility in each group. We suggest that, even when carnivores and primates would theoretically benefit from the same adaptations with respect to behavioural flexibility, carnivores may nevertheless exhibit less behavioural flexibility than primates because of constraints imposed by past adaptations in the morphology of the limbs and skull. Phylogenetic analysis consistent with this idea suggests greater evolutionary lability in relative brain size within families of primates than carnivores. Thus, consideration of developmental constraints may help elucidate variation in mammalian behavioural flexibility.

  4. Multiple benefits of alloparental care in a fluctuating environment

    Science.gov (United States)

    2018-01-01

    Although cooperatively breeding vertebrates occur disproportionately in unpredictable environments, the underlying mechanism shaping this biogeographic pattern remains unclear. Cooperative breeding may buffer against harsh conditions (hard life hypothesis), or additionally allow for sustained breeding under benign conditions (temporal variability hypothesis). To distinguish between the hard life and temporal variability hypotheses, we investigated whether the number of alloparents at a nest increased reproductive success or load-lightening in superb starlings (Lamprotornis superbus), and whether these two types of benefits varied in harsh and benign years. We found that mothers experienced both types of benefits consistent with the temporal variability hypothesis, as larger contingents of alloparents increased the number of young fledged while simultaneously allowing mothers to reduce their provisioning rates under both harsh and benign rainfall conditions. By contrast, fathers experienced load-lightening only under benign rainfall conditions, suggesting that cooperative breeding may serve to take advantage of unpredictable benign breeding seasons when they do occur. Cooperative breeding in unpredictable environments may thus promote flexibility in offspring care behaviour, which could mitigate variability in the cost of raising young. Our results highlight the importance of considering how offspring care decisions vary among breeding roles and across fluctuating environmental conditions. PMID:29515910

  5. Multiple benefits of alloparental care in a fluctuating environment.

    Science.gov (United States)

    Guindre-Parker, Sarah; Rubenstein, Dustin R

    2018-02-01

    Although cooperatively breeding vertebrates occur disproportionately in unpredictable environments, the underlying mechanism shaping this biogeographic pattern remains unclear. Cooperative breeding may buffer against harsh conditions (hard life hypothesis), or additionally allow for sustained breeding under benign conditions (temporal variability hypothesis). To distinguish between the hard life and temporal variability hypotheses, we investigated whether the number of alloparents at a nest increased reproductive success or load-lightening in superb starlings ( Lamprotornis superbus ), and whether these two types of benefits varied in harsh and benign years. We found that mothers experienced both types of benefits consistent with the temporal variability hypothesis, as larger contingents of alloparents increased the number of young fledged while simultaneously allowing mothers to reduce their provisioning rates under both harsh and benign rainfall conditions. By contrast, fathers experienced load-lightening only under benign rainfall conditions, suggesting that cooperative breeding may serve to take advantage of unpredictable benign breeding seasons when they do occur. Cooperative breeding in unpredictable environments may thus promote flexibility in offspring care behaviour, which could mitigate variability in the cost of raising young. Our results highlight the importance of considering how offspring care decisions vary among breeding roles and across fluctuating environmental conditions.

  6. Fluctuating ideal-gas lattice Boltzmann method with fluctuation dissipation theorem for nonvanishing velocities.

    Science.gov (United States)

    Kaehler, G; Wagner, A J

    2013-06-01

    Current implementations of fluctuating ideal-gas descriptions with the lattice Boltzmann methods are based on a fluctuation dissipation theorem, which, while greatly simplifying the implementation, strictly holds only for zero mean velocity and small fluctuations. We show how to derive the fluctuation dissipation theorem for all k, which was done only for k=0 in previous derivations. The consistent derivation requires, in principle, locally velocity-dependent multirelaxation time transforms. Such an implementation is computationally prohibitively expensive but, with a small computational trick, it is feasible to reproduce the correct FDT without overhead in computation time. It is then shown that the previous standard implementations perform poorly for non vanishing mean velocity as indicated by violations of Galilean invariance of measured structure factors. Results obtained with the method introduced here show a significant reduction of the Galilean invariance violations.

  7. Magnetic fluctuations in heavy fermion systems

    International Nuclear Information System (INIS)

    Broholm, C.L.

    1989-06-01

    Magnetic order and fluctuations in the heavy Fermion systems UPt 3 , U 2 Zn 17 and URu 2 Si 2 have been studied by neutron scattering. Single crystalline samples and triple-axis neutron-scattering techniques with energy transfers between 0 and 40 meV and energy resolutions between 0.1 meV and 4 meV have been employed. UPt 3 develops an antiferromagnetically ordered moment of (0.02±0.005) μ B below T N = 5 K which doubles the unit cell in the basal plane and coexists with superconductivity below T c = 0.5 K. The magnetic fluctuations are relaxational, and enhanced at the antiferromagnetic zone center in a low-energy regime. The characteristic zone-center relaxation energy is 0.3 meV. The temperature- and field-dependence of the antiferromagnetic order in the superconducting phase suggest a close relation between these two properties in UPt 3 . U 2 Zn 17 has a broad spectrum of magnetic fluctuations, even below T N = 9.7 K, of which the transverse part below 10 meV is strongly enhanced at the antiferromagnetic zone center. The system has an anomalously extended critical region and the antiferromagnetic phase transition seems to be driven by the temperature-dependence of an effective RKKY interaction, as anticipated theoretically. URu 2 Si 2 , a strongly anisotropic heavy Fermion system, has a high-energy regime of antiferromagnetically-correlated overdamped magnetic fluctuations. Below T N = 17.5 K weak antiferromagnetic order, μ = (0.04±0.01)μ B , with finite correlations along the tetragonal c axis, develops along with a low-energy regime of strongly dispersive singlet-singlet excitations. Below T c = 1 K antiferromagnetism coexists with superconductivity. A phenomenological model describing the exchange-enhanced overdamped magnetic fluctuations of heavy Fermion systems is proposed. Our experimental results are compared to the anomalous bulk properties of heavy Fermion systems, and to magnetic fluctuations in other metallic magnets. (orig.)

  8. Theory of electromagnetic fluctuations for magnetized multi-species plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Navarro, Roberto E., E-mail: roberto.navarro@ug.uchile.cl; Muñoz, Víctor [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Araneda, Jaime [Departamento de Física, Universidad de Concepción, Concepción 4070386 (Chile); Moya, Pablo S. [NASA Goddard Space Flight Center, Heliophysics Science Division, Geospace Physics Laboratory, Mail Code 673, Greenbelt, Maryland 20771 (United States); Department of Physics, Catholic University of America, Washington, D. C. 20064 (United States); Viñas, Adolfo F. [NASA Goddard Space Flight Center, Heliophysics Science Division, Geospace Physics Laboratory, Mail Code 673, Greenbelt, Maryland 20771 (United States); Valdivia, Juan A. [Departamento de Física, Facultad de Ciencias, Universidad de Chile, Casilla 653, Santiago (Chile); Centro de Estudios Interdisciplinarios Básicos y Aplicados en Complejidad, CEIBA complejidad, Bogotá (Colombia)

    2014-09-15

    Analysis of electromagnetic fluctuations in plasma provides relevant information about the plasma state and its macroscopic properties. In particular, the solar wind persistently sustains a small but detectable level of magnetic fluctuation power even near thermal equilibrium. These fluctuations may be related to spontaneous electromagnetic fluctuations arising from the discreteness of charged particles. Here, we derive general expressions for the plasma fluctuations in a multi-species plasma following arbitrary distribution functions. This formalism, which generalizes and includes previous works on the subject, is then applied to the generation of electromagnetic fluctuations propagating along a background magnetic field in a plasma of two proton populations described by drifting bi-Maxwellians.

  9. Two-mode bosonic quantum metrology with number fluctuations

    Science.gov (United States)

    De Pasquale, Antonella; Facchi, Paolo; Florio, Giuseppe; Giovannetti, Vittorio; Matsuoka, Koji; Yuasa, Kazuya

    2015-10-01

    We search for the optimal quantum pure states of identical bosonic particles for applications in quantum metrology, in particular, in the estimation of a single parameter for the generic two-mode interferometric setup. We consider the general case in which the total number of particles is fluctuating around an average N with variance Δ N2 . By recasting the problem in the framework of classical probability, we clarify the maximal accuracy attainable and show that it is always larger than the one reachable with a fixed number of particles (i.e., Δ N =0 ). In particular, for larger fluctuations, the error in the estimation diminishes proportionally to 1 /Δ N , below the Heisenberg-like scaling 1 /N . We also clarify the best input state, which is a quasi-NOON state for a generic setup and, for some special cases, a two-mode Schrödinger-cat state with a vacuum component. In addition, we search for the best state within the class of pure Gaussian states with a given average N , which is revealed to be a product state (with no entanglement) with a squeezed vacuum in one mode and the vacuum in the other.

  10. Currents and fluctuations of quantum heat transport in harmonic chains

    International Nuclear Information System (INIS)

    Motz, T; Ankerhold, J; Stockburger, J T

    2017-01-01

    Heat transport in open quantum systems is particularly susceptible to the modeling of system–reservoir interactions. It thus requires us to consistently treat the coupling between a quantum system and its environment. While perturbative approaches are successfully used in fields like quantum optics and quantum information, they reveal deficiencies—typically in the context of thermodynamics, when it is essential to respect additional criteria such as fluctuation-dissipation theorems. We use a non-perturbative approach for quantum dissipative dynamics based on a stochastic Liouville–von Neumann equation to provide a very general and extremely efficient formalism for heat currents and their correlations in open harmonic chains. Specific results are derived not only for first- but also for second-order moments, which requires us to account for both real and imaginary parts of bath–bath correlation functions. Spatiotemporal patterns are compared with weak coupling calculations. The regime of stronger system–reservoir couplings gives rise to an intimate interplay between reservoir fluctuations and heat transfer far from equilibrium. (paper)

  11. Individual Differences: Factors Affecting Employee Utilization of Flexible Work Arrangements

    Science.gov (United States)

    Lambert, Alysa D.; Marler, Janet H.; Gueutal, Hal G.

    2008-01-01

    This study investigated individual and organizational factors that predict an individual's choice to use flexible work arrangements (FWAs). Survey data was collected from 144 employees in two different organizations. The results revealed several significant predictors of FWAs: tenure, hours worked per week, supervisory responsibilities,…

  12. Flexibility and security : National social models in transitional labour markets

    NARCIS (Netherlands)

    Muffels, R.J.A.; Crouch, Colin; Wilthagen, A.C.J.M.

    2014-01-01

    Aggregate and individual data are used to test the association between employment performance and different ways of reconciling flexibility and security in European labour markets. Particular use is made of statistics on individuals’ labour market transitions as revealed by national labour force

  13. Non-statistical fluctuations in fragmentation of target nuclei in high energy nuclear interactions

    Energy Technology Data Exchange (ETDEWEB)

    Ghosh, Dipak; Ghosh, Premomoy; Ghosh, Alokananda; Roy, Jaya [Jadavpur Univ., Calcutta (India)

    1994-07-01

    Analysis of target fragmented ''black'' particles in nuclear emulsion from high energy relativistic interactions initiated by [sup 16]O at 2.1 GeV/nucleon and [sup 12]C and [sup 24]Mg at 4.5 GeV/nucleon reveal the existence of non-statistical fluctuations in the azimuthal plane of interaction. The asymmetry or the non-statistical fluctuations, while found to be independent of projectile mass or incident energy, are dependent on the excitation energy of the target nucleus. (Author).

  14. Non-statistical fluctuations in fragmentation of target nuclei in high energy nuclear interactions

    International Nuclear Information System (INIS)

    Ghosh, Dipak; Ghosh, Premomoy; Ghosh, Alokananda; Roy, Jaya

    1994-01-01

    Analysis of target fragmented ''black'' particles in nuclear emulsion from high energy relativistic interactions initiated by 16 O at 2.1 GeV/nucleon and 12 C and 24 Mg at 4.5 GeV/nucleon reveal the existence of non-statistical fluctuations in the azimuthal plane of interaction. The asymmetry or the non-statistical fluctuations, while found to be independent of projectile mass or incident energy, are dependent on the excitation energy of the target nucleus. (Author)

  15. Economic Aspects of Load Following in Flexible Operation. Annex IV

    International Nuclear Information System (INIS)

    2018-01-01

    To supplement this publication, the IAEA has prepared an economic study to quantify the cost–revenue aspects for nuclear power plant operations in mixed energy systems, including flexible operation. The purpose of this study was to explore economic opportunities for using nuclear energy in future power markets with increasing deployment of renewable energy, specifically investigating the following: — How much power ramping could future reactors support and at what penalty? — What type of flexibility is required on the grid — larger down power and faster ramp rate for load following or increased start/stop capability? What is the optimal level of flexible capacity in a system? — How can nuclear energy be used in different grid environments (e.g. different sizes or complexities) to cope with variable power demand and fluctuating supply from renewable energy sources? — What are the economic implications (including different revenue streams) for using large reactors? — How do market regulation and real market interaction affect the economic viability of using nuclear power under the various system modes? To answer these questions, an analytical case study approach, which directly assesses the difference between energy specific production costs for a baseload nuclear system and a load following nuclear system, was selected. Such a study, based on a large scale country level power plant dispatching model, could assess the difference between the total short term costs of producing a given amount of electricity by both types of operation in a particular system. This approach may answer the questions of whether adding flexible nuclear operation to the power system is capable of generating overall system benefits by minimizing total system costs at different levels. This annex briefly summarizes the IAEA study, together with insights from the available sources, and underlines the pressing needs in filling the missing knowledge gaps in the economic aspects of

  16. An integrated approach to inventory and flexible capacity management subject to fixed costs and non-stationary stochastic demand

    NARCIS (Netherlands)

    Tan, T.; Alp, O.

    2009-01-01

    In a manufacturing system with flexible capacity, inventory management can be coupled with capacity management in order to handle fluctuations in demand more effectively. Typical examples include the effective use of temporary workforce and overtime production. In this paper, we discuss an

  17. Cytoskeleton dynamics: Fluctuations within the network

    International Nuclear Information System (INIS)

    Bursac, Predrag; Fabry, Ben; Trepat, Xavier; Lenormand, Guillaume; Butler, James P.; Wang, Ning; Fredberg, Jeffrey J.; An, Steven S.

    2007-01-01

    Out-of-equilibrium systems, such as the dynamics of a living cytoskeleton (CSK), are inherently noisy with fluctuations arising from the stochastic nature of the underlying biochemical and molecular events. Recently, such fluctuations within the cell were characterized by observing spontaneous nano-scale motions of an RGD-coated microbead bound to the cell surface [Bursac et al., Nat. Mater. 4 (2005) 557-561]. While these reported anomalous bead motions represent a molecular level reorganization (remodeling) of microstructures in contact with the bead, a precise nature of these cytoskeletal constituents and forces that drive their remodeling dynamics are largely unclear. Here, we focused upon spontaneous motions of an RGD-coated bead and, in particular, assessed to what extent these motions are attributable to (i) bulk cell movement (cell crawling), (ii) dynamics of focal adhesions, (iii) dynamics of lipid membrane, and/or (iv) dynamics of the underlying actin CSK driven by myosin motors

  18. Chiral vacuum fluctuations in quantum gravity.

    Science.gov (United States)

    Magueijo, João; Benincasa, Dionigi M T

    2011-03-25

    We examine tensor perturbations around a de Sitter background within the framework of Ashtekar's variables and its cousins parameterized by the Immirzi parameter γ. At the classical level we recover standard cosmological perturbation theory, with illuminating insights. Quantization leads to real novelties. In the low energy limit we find a second quantized theory of gravitons which displays different vacuum fluctuations for right and left gravitons. Nonetheless right and left gravitons have the same (positive) energies, resolving a number of paradoxes suggested in the literature. The right-left asymmetry of the vacuum fluctuations depends on γ and the ordering of the Hamiltonian constraint, and it would leave a distinctive imprint in the polarization of the cosmic microwave background, thus opening quantum gravity to observational test.

  19. Molecular thermodynamics using fluctuation solution theory

    DEFF Research Database (Denmark)

    Ellegaard, Martin Dela

    . The framework relates thermodynamic variables to molecular pair correlation functions of liquid mixtures. In this thesis, application of the framework is illustrated using two approaches: 1. Solubilities of solid solutes in mixed solvent systems are determined from fluctuation solution theory application......Properties of chemicals and their mutual phase equilibria are critical variables in process design. Reliable estimates of relevant equilibrium properties, from thermodynamic models, can form the basis of good decision making in the development phase of a process design, especially when access...... to relevant experimental data is limited. This thesis addresses the issue of generating and using simple thermodynamic models within a rigorous statistical mechanical framework, the so-called fluctuation solution theory, from which relations connecting properties and phase equilibria can be obtained...

  20. Fluctuations in a Levy flight gas

    International Nuclear Information System (INIS)

    Fogedby, H.C.; Jensen, H.J.

    1991-01-01

    We consider the density fluctuations of an ideal Brownian gas of particles performing Levy flights characterized by the index f. We find that the fluctuations scale as ΔN(t)∝t H , where the Hurst exponent H locks onto the universal value 1/4 for Levy flights with a finite root mean square range (f>2). For Levy flights with a finite mean range but infinite root mean square range (1< f<2) the Hurst exponent H=1/2f. For infinite range Levy flights (f<1) the Hurst exponent locks onto the value 1/2. The corresponding power spectrum scales with an exponent 1+2H, independent of dimension. (orig.)

  1. Detecting quantum critical points using bipartite fluctuations.

    Science.gov (United States)

    Rachel, Stephan; Laflorencie, Nicolas; Song, H Francis; Le Hur, Karyn

    2012-03-16

    We show that the concept of bipartite fluctuations F provides a very efficient tool to detect quantum phase transitions in strongly correlated systems. Using state-of-the-art numerical techniques complemented with analytical arguments, we investigate paradigmatic examples for both quantum spins and bosons. As compared to the von Neumann entanglement entropy, we observe that F allows us to find quantum critical points with much better accuracy in one dimension. We further demonstrate that F can be successfully applied to the detection of quantum criticality in higher dimensions with no prior knowledge of the universality class of the transition. Promising approaches to experimentally access fluctuations are discussed for quantum antiferromagnets and cold gases.

  2. Memory versus fluctuations in heavy ion fusion

    Science.gov (United States)

    Chushnyakova, M. V.; Gontchar, I. I.

    2013-09-01

    We model collisions of complex nuclei leading to capture using the Langevin equations, with white and colored noises and with instant and retarding friction, respectively. The friction force is supposed to be proportional to the squared derivative of the strong nucleus-nucleus interaction potential (SnnP). The SnnP is calculated within the framework of the double folding model with the density-dependent M3Y NN-forces possessing the finite range exchange term. Comparing results obtained in the presence and in the absence of fluctuations, we found that the fluctuations influence the capture cross sections weakly, typically within 5%. In contradistinction, the influence of the memory effects is found to be about 20%.

  3. Spark-safe mechanical fluctuation sensor

    Energy Technology Data Exchange (ETDEWEB)

    Retek, S; Galisz, T

    1979-04-20

    The subject of the invention is a mechanical fluctuation sensor in a spark-safe design for use at mines which are dangerous for gas, as an element of different systems for remote control information transfer. The patented sensor of mechanical fluctuations contains: magnetic-induction transformer characterized by the fact that its inert mass consists of a plane permanent magnet placed in the suspended state on springs between 2 coils, which together with their cores are rigidly fixed to the walls of the ferromagnetic vessels. The ends of the coil windings are interconnected, while the beginnings of the windings are lead out with connection to the outlet of the electronic amplifier with binary outlet signal. The electronic amplifier is placed between the transformer in the common ferromagnetic housing which is a screen for protection from the effect of external magnetic fields.

  4. Phase Transition in Protocols Minimizing Work Fluctuations

    Science.gov (United States)

    Solon, Alexandre P.; Horowitz, Jordan M.

    2018-05-01

    For two canonical examples of driven mesoscopic systems—a harmonically trapped Brownian particle and a quantum dot—we numerically determine the finite-time protocols that optimize the compromise between the standard deviation and the mean of the dissipated work. In the case of the oscillator, we observe a collection of protocols that smoothly trade off between average work and its fluctuations. However, for the quantum dot, we find that as we shift the weight of our optimization objective from average work to work standard deviation, there is an analog of a first-order phase transition in protocol space: two distinct protocols exchange global optimality with mixed protocols akin to phase coexistence. As a result, the two types of protocols possess qualitatively different properties and remain distinct even in the infinite duration limit: optimal-work-fluctuation protocols never coalesce with the minimal-work protocols, which therefore never become quasistatic.

  5. Prevention of Employees Fluctuation in IT

    Directory of Open Access Journals (Sweden)

    Libor Mesicek

    2017-10-01

    Full Text Available The aim of this paper is to present results of implementation fluctuation preventing counter-measures among other positions in IT department. In 2017 there is still one of the lowest unemployment rates in the history of the Czech Republic (especially in IT and companies are trying to preserve and prevent their key employees from moving to another employer. One of the tools, which could help reduce this risk, is providing additional education, certification and qualification with laying great emphasis on most valuable and essential personnel. The paper present updated results after 6 months since the company started with selection of high risks employees. It has been found that group of employees with high risk of leaving the company has shrunk and overall fluctuation index has also plunged.

  6. Extremal-point densities of interface fluctuations

    International Nuclear Information System (INIS)

    Toroczkai, Z.; Korniss, G.; Das Sarma, S.; Zia, R. K. P.

    2000-01-01

    We introduce and investigate the stochastic dynamics of the density of local extrema (minima and maxima) of nonequilibrium surface fluctuations. We give a number of analytic results for interface fluctuations described by linear Langevin equations, and for on-lattice, solid-on-solid surface-growth models. We show that, in spite of the nonuniversal character of the quantities studied, their behavior against the variation of the microscopic length scales can present generic features, characteristic of the macroscopic observables of the system. The quantities investigated here provide us with tools that give an unorthodox approach to the dynamics of surface morphologies: a statistical analysis from the short-wavelength end of the Fourier decomposition spectrum. In addition to surface-growth applications, our results can be used to solve the asymptotic scalability problem of massively parallel algorithms for discrete-event simulations, which are extensively used in Monte Carlo simulations on parallel architectures. (c) 2000 The American Physical Society

  7. Effective tension and fluctuations in active membranes.

    Science.gov (United States)

    Loubet, Bastien; Seifert, Udo; Lomholt, Michael Andersen

    2012-03-01

    We calculate the fluctuation spectrum of the shape of a lipid vesicle or cell exposed to a nonthermal source of noise. In particular, we take constraints on the membrane area and the volume of fluid that it encapsulates into account when obtaining expressions for the dependency of the membrane tension on the noise. We then investigate three possible origins of the nonthermal noise taken from the literature: A direct force, which models an external medium pushing on the membrane, a curvature force, which models a fluctuating spontaneous curvature, and a permeation force coming from an active transport of fluid through the membrane. For the direct force and curvature force cases, we compare our results to existing experiments on active membranes.

  8. Intrinsic flexibility of B-DNA: the experimental TRX scale.

    Science.gov (United States)

    Heddi, Brahim; Oguey, Christophe; Lavelle, Christophe; Foloppe, Nicolas; Hartmann, Brigitte

    2010-01-01

    B-DNA flexibility, crucial for DNA-protein recognition, is sequence dependent. Free DNA in solution would in principle be the best reference state to uncover the relation between base sequences and their intrinsic flexibility; however, this has long been hampered by a lack of suitable experimental data. We investigated this relationship by compiling and analyzing a large dataset of NMR (31)P chemical shifts in solution. These measurements reflect the BI BII equilibrium in DNA, intimately correlated to helicoidal descriptors of the curvature, winding and groove dimensions. Comparing the ten complementary DNA dinucleotide steps indicates that some steps are much more flexible than others. This malleability is primarily controlled at the dinucleotide level, modulated by the tetranucleotide environment. Our analyses provide an experimental scale called TRX that quantifies the intrinsic flexibility of the ten dinucleotide steps in terms of Twist, Roll, and X-disp (base pair displacement). Applying the TRX scale to DNA sequences optimized for nucleosome formation reveals a 10 base-pair periodic alternation of stiff and flexible regions. Thus, DNA flexibility captured by the TRX scale is relevant to nucleosome formation, suggesting that this scale may be of general interest to better understand protein-DNA recognition.

  9. Transform and filtration methods in fluctuation analysis

    International Nuclear Information System (INIS)

    Saxe, R.F.

    1976-01-01

    Digitized fluctuation signals from an ex-core ion-chamber of a PWR were analysed to produce a Power Spectral Density, (PSD), curve by two means: (1) by digital filter techniques and (2) by a Fast Fourier Transform program. For both these methods, the effects of the precision of the input data were investigated and it is shown that reasonably good PSD curves may be obtained using very poor input precision. (author)

  10. Diffusion of particles on a fluctuating surface

    Czech Academy of Sciences Publication Activity Database

    Tarasenko, Alexander; Jastrabík, Lubomír

    2011-01-01

    Roč. 29, č. 5 (2011), s. 487-494 ISSN 0263-6174 R&D Projects: GA AV ČR KAN301370701; GA MŠk(CZ) 1M06002 Institutional research plan: CEZ:AV0Z10100522 Keywords : kinetic Monte Carlo simulations * diffusion on a fluctuating surface Subject RIV: BH - Optics, Masers, Lasers Impact factor: 0.606, year: 2011

  11. Diagnostic needs for fluctuations and transport studies

    International Nuclear Information System (INIS)

    Carreras, B.A.

    1992-01-01

    The identification of fundamental transport mechanisms in magnetically confined plasmas is a critical issue for the magnetic fusion program. Recent progress in understanding fluctuations and transport is well correlated with the development and use of new diagnostics, but there a great deal of information is still missing. Some of the required measurements are well beyond our present diagnostic capabilities, but some are within reach and could answer critical questions in this area of research. Some of these critical issues are discussed

  12. Fluctuations in interacting particle systems with memory

    International Nuclear Information System (INIS)

    Harris, Rosemary J

    2015-01-01

    We consider the effects of long-range temporal correlations in many-particle systems, focusing particularly on fluctuations about the typical behaviour. For a specific class of memory dependence we discuss the modification of the large deviation principle describing the probability of rare currents and show how superdiffusive behaviour can emerge. We illustrate the general framework with detailed calculations for a memory-dependent version of the totally asymmetric simple exclusion process as well as indicating connections to other recent work

  13. Dynamical fluctuations for semi-Markov processes

    Czech Academy of Sciences Publication Activity Database

    Maes, C.; Netočný, Karel; Wynants, B.

    2009-01-01

    Roč. 42, č. 36 (2009), 365002/1-365002/21 ISSN 1751-8113 R&D Projects: GA ČR GC202/07/J051 Institutional research plan: CEZ:AV0Z10100520 Keywords : nonequilibrium fluctuations * semi-Markov processes Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.577, year: 2009 http://www.iop.org/EJ/abstract/1751-8121/42/36/365002

  14. Localization of waves in a fluctuating plasma

    International Nuclear Information System (INIS)

    Escande, D.F.; Souillard, B.

    1984-01-01

    We present the first application of localization theory to plasma physics: Density fluctuations induce exponential localization of longitudinal and transverse electron plasma waves, i.e., the eigenmodes have an amplitude decreasing exponentially for large distances without any dissipative mechanism in the plasma. This introduces a new mechanism for converting a convective instability into an absolute one. Localization should be observable in clear-cut experiments

  15. China; Sources of Real Exchange Rate Fluctuations

    OpenAIRE

    Tao Wang

    2004-01-01

    This paper reviews the evolution of China's real effective exchange rate between 1980 and 2002, and uses a structural vector autoregression model to study the relative importance of different types of macroeconomic shocks for fluctuations in the real exchange rate. The structural decomposition shows that relative real demand and supply shocks account for most of the variations in real exchange rate changes during the estimation period. The paper also finds that supply shocks are as important ...

  16. Commodity Price Fluctuations: A Century of Analysis

    OpenAIRE

    Walter Labys

    2005-01-01

    Commodity prices again! The twentieth century has only been the latest spectator to the impacts and importance of commodity price fluctuations. It is reasonably well known that commodity price records have come down to us from the ancient civilizations of India, Mesopotamia, Egypt, Greece and Rome. Earlier in the century, formal research began on the relationships between agricultural demand, supply and prices in a market context. This research not only evolved in sophistication but extended ...

  17. Pricing of Fluctuations in Electricity Markets

    OpenAIRE

    Tsitsiklis, John N.; Xu, Yunjian

    2012-01-01

    In an electric power system, demand fluctuations may result in significant ancillary cost to suppliers. Furthermore, in the near future, deep penetration of volatile renewable electricity generation is expected to exacerbate the variability of demand on conventional thermal generating units. We address this issue by explicitly modeling the ancillary cost associated with demand variability. We argue that a time-varying price equal to the suppliers' instantaneous marginal cost may not achieve s...

  18. Holocene glacial fluctuations in southern South America

    Science.gov (United States)

    Reynhout, S.; Sagredo, E. A.; Kaplan, M. R.; Aravena, J. C.; Martini, M. A.; Strelin, J. A.; Schaefer, J. M.

    2016-12-01

    Understanding the timing and magnitude of former glacier fluctuations is critical to decipher long-term climatic trends and to unravel both natural cycles and human impact on the current glacial behavior. Despite more than seven decades of research efforts, a unifying model of Holocene glacial fluctuations in Southern South America remains elusive. Here, we present the state-of-the-art regarding the timing of Holocene glacial fluctuation in southern Patagonia-Tierra del Fuego, with a focus on a new generation of high-resolution radiocarbon and 10Be surface exposure dating chronologies. Recently acquired evidence suggest that after receding from advanced Late Glacial positions, Patagonian glaciers were for the most part close to, or even behind, present ice margins during the Early Holocene. On the other hand, emerging chronologies indicate that in some areas there were extensive expansions (century scale?) that punctuated the warm interval. Subsequently, we have evidence of multiple millennial timescale glacial advances starting in the middle Holocene. Several glacial maxima are defined by moraines and other landforms from 7000 years ago to the 19th century, with a gap sometime between 4,500 and 2,500 years ago. The last set of advances began around 800-600 years ago. Although glacial activity is documented in Patagonia at the same time as the European Little Ice Age, the extent of these glacial events are less prominent than those of the mid-Holocene. The causes that may explain these glacial fluctuations remain elusive. Finally, we discuss ongoing efforts to better define the timing and extent of Holocene glaciations in southern South America, and to establish the basis to test competing hypothesis of regional Holocene climate variability.

  19. Study of fluctuations. Variance measurement on Proserpine

    International Nuclear Information System (INIS)

    Berger, F.; Renaux, R.

    1960-01-01

    The authors present an equipment designed for the study of the statistical fluctuation of the number of neutrons existing in a pile in the neighbourhood of its critical status. This equipment must allow series of counts of constant duration per series, and triggered by a random process. The counting assembly is presented (principle, description and operation), as well as the memorization assembly for a slow or quick count triggering

  20. K/pi Fluctuations at Relativistic Energies

    Czech Academy of Sciences Publication Activity Database

    Abelev, B. I.; Aggarwal, M. M.; Ahammed, Z.; Anderson, B. D.; Arkhipkin, D.; Averichev, G. S.; Balewski, J.; Barannikova, O.; Barnby, L. S.; Baudot, J.; Baumgart, S.; Beavis, D.R.; Bellwied, R.; Benedosso, F.; Betancourt, M.J.; Betts, R. R.; Bhasin, A.; Bhati, A.K.; Bichsel, H.; Bielčík, Jaroslav; Bielčíková, Jana; Biritz, B.; Bland, L.C.; Bombara, M.; Bonner, B. E.; Botje, M.; Bouchet, J.; Braidot, E.; Brandin, A. V.; Bruna, E.; Bueltmann, S.; Burton, T. P.; Bysterský, Michal; Cai, X.Z.; Caines, H.; Sanchez, M.C.D.; Catu, O.; Cebra, D.; Cendejas, R.; Cervantes, M.C.; Chajecki, Z.; Chaloupka, Petr; Chattopadhyay, S.; Chen, H.F.; Chen, J.H.; Cheng, J.; Cherney, M.; Chikanian, A.; Choi, K.E.; Christie, W.; Clarke, R.F.; Codrington, M.J.M.; Corliss, R.; Cormier, T.M.; Coserea, R. M.; Cramer, J. G.; Crawford, H. J.; Das, D.; Dash, S.; Daugherity, M.; De Silva, L.C.; Dedovich, T. G.; DePhillips, M.; Derevschikov, A.A.; de Souza, R.D.; Didenko, L.; Djawotho, P.; Dunlop, J.C.; Mazumdar, M.R.D.; Edwards, W.R.; Efimov, L.G.; Elhalhuli, E.; Elnimr, M.; Emelianov, V.; Engelage, J.; Eppley, G.; Erazmus, B.; Estienne, M.; Eun, L.; Fachini, P.; Fatemi, R.; Fedorisin, J.; Feng, A.; Filip, P.; Finch, E.; Fine, V.; Fisyak, Y.; Gagliardi, C. A.; Gaillard, L.; Ganti, M. S.; Gangaharan, D.R.; Garcia-Solis, E.J.; Geromitsos, A.; Geurts, F.; Ghazikhanian, V.; Ghosh, P.; Gorbunov, Y.N.; Gordon, A.; Grebenyuk, O.; Grosnick, D.; Grube, B.; Guertin, S.M.; Guimaraes, K.S.F.F.; Gupta, A.; Gupta, N.; Guryn, W.; Haag, B.; Hallman, T.J.; Hamed, A.; Harris, J.W.; He, W.; Heinz, M.; Heppelmann, S.; Hippolyte, B.; Hirsch, A.; Hjort, E.; Hoffman, A.M.; Hoffmann, G.W.; Hofman, D.J.; Hollis, R.S.; Huang, H.Z.; Humanic, T.J.; Igo, G.; Iordanova, A.; Jacobs, P.; Jacobs, W.W.; Jakl, Pavel; Jena, C.; Jin, F.; Jones, C.L.; Jones, P.G.; Joseph, J.; Judd, E.G.; Kabana, S.; Kajimoto, K.; Kang, K.; Kapitán, Jan; Keane, D.; Kechechyan, A.; Kettler, D.; Khodyrev, V.Yu.; Kikola, D.P.; Kiryluk, J.; Kisiel, A.; Klein, S.R.; Knospe, A.G.; Kocoloski, A.; Koetke, D.D.; Kopytine, M.; Korsch, W.; Kotchenda, L.; Kushpil, Vasilij; Kravtsov, P.; Kravtsov, V.I.; Krueger, K.; Krus, M.; Kuhn, C.; Kumar, L.; Kurnadi, P.; Lamont, M.A.C.; Landgraf, J.M.; LaPointe, S.; Lauret, J.; Lebedev, A.; Lednický, Richard; Lee, Ch.; Lee, J.H.; Leight, W.; LeVine, M.J.; Li, N.; Li, C.; Li, Y.; Lin, G.; Lindenbaum, S.J.; Lisa, M.A.; Liu, F.; Liu, J.; Liu, L.; Ljubicic, T.; Llope, W.J.; Longacre, R.S.; Love, W.A.; Lu, Y.; Ludlam, T.; Ma, G.L.; Ma, Y.G.; Mahapatra, D.P.; Majka, R.; Mall, O.I.; Mangotra, L.K.; Manweiler, R.; Margetis, S.; Markert, C.; Matis, H.S.; Matulenko, Yu.A.; McShane, T.S.; Meschanin, A.; Milner, R.; Minaev, N.G.; Mioduszewski, S.; Mischke, A.; Mitchell, J.; Mohanty, B.; Morozov, D.A.; Munhoz, M. G.; Nandi, B.K.; Nattrass, C.; Nayak, T. K.; Nelson, J.M.; Netrakanti, P.K.; Ng, M.J.; Nogach, L.V.; Nurushev, S.B.; Odyniec, G.; Ogawa, A.; Okada, H.; Okorokov, V.; Olson, D.; Pachr, M.; Page, B.S.; Pal, S.K.; Pandit, Y.; Panebratsev, Y.; Panitkin, S.Y.; Pawlak, T.; Peitzmann, T.; Perevoztchikov, V.; Perkins, C.; Peryt, W.; Phatak, S.C.; Poljak, N.; Poskanzer, A.M.; Potukuchi, B.V.K.S.; Prindle, D.; Pruneau, C.; Pruthi, N.K.; Putschke, J.; Raniwala, R.; Raniwala, S.; Ray, R.L.; Redwine, R.; Reed, R.; Ridiger, A.; Ritter, H.G.; Roberts, J.B.; Rogachevskiy, O.V.; Romero, J.L.; Rose, A.; Roy, C.; Ruan, L.; Russcher, M.J.; Sahoo, R.; Sakrejda, I.; Salur, S.; Sandweiss, J.; Sarsour, M.; Schambach, J.; Scharenberg, R.P.; Schmitz, N.; Seger, J.; Selyuzhenkov, I.; Seyboth, P.; Shabetai, A.; Shahaliev, E.; Shao, M.; Sharma, M.; Shi, S.S.; Shi, X.H.; Sichtermann, E.P.; Simon, F.; Singaraju, R.N.; Skoby, M.J.; Smirnov, N.; Snellings, R.; Sorensen, P.; Sowinski, J.; Spinka, H.M.; Srivastava, B.; Stadnik, A.; Stanislaus, T.D.S.; Staszak, D.; Strikhanov, M.; Stringfellow, B.; Suaide, A.A.P.; Suarez, M.C.; Subba, N.L.; Šumbera, Michal; Sun, X.M.; Sun, Y.; Sun, Z.; Surrow, B.; Symons, T.J.M.; de Toledo, A. S.; Takahashi, J.; Tang, A.H.; Tang, Z.; Tarini, L.H.; Tarnowsky, T.; Thein, D.; Thomas, J.H.; Tian, J.; Timmins, A.R.; Timoshenko, S.; Tlustý, David; Tokarev, M. V.; Tram, V.N.; Trattner, A.L.; Trentalange, S.; Tribble, R. E.; Tsai, O.D.; Ulery, J.; Ullrich, T.; Underwood, D.G.; Van Buren, G.; van Leeuwen, M.; Molen, A.M.V.; Vanfossen, J.A.; Varma, R.; Vasconcelos, G.M.S.; Vasilevski, I.M.; Vasiliev, A.; Videbaek, F.; Vigdor, S.E.; Viyogi, Y. P.; Vokal, S.; Voloshin, S.A.; Wada, M.; Walker, M.; Wang, F.; Wang, G.; Wang, J.S.; Wang, Q.; Wang, X.; Wang, X.L.; Wang, Y.; Webb, G.; Webb, J.C.; Westfall, G.D.; Whitten, C.; Wieman, H.; Wissink, S.W.; Witt, R.; Wu, Y.; Xie, W.; Xu, N.; Xu, Q.H.; Xu, Y.; Xu, Z.; Yang, P.; Yepes, P.; Yip, K.; Yoo, I.K.; Yue, Q.; Zawisza, M.; Zbroszczyk, H.; Zhan, W.; Zhang, S.; Zhang, W.M.; Zhang, X.P.; Zhang, Y.; Zhang, Z.P.; Zhao, Y.; Zhong, C.; Zhou, J.; Zoulkarneev, R.; Zoulkarneeva, Y.; Zuo, J.X.

    2009-01-01

    Roč. 103, č. 9 (2009), 092301/1-092301/6 ISSN 0031-9007 R&D Projects: GA ČR GA202/07/0079; GA MŠk LC07048; GA MŠk LA09013 Institutional research plan: CEZ:AV0Z10480505; CEZ:AV0Z10100502 Keywords : heavy-ion collisions * strangeness * fluctuations Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 7.328, year: 2009

  1. Equilibrium fluctuation energy of gyrokinetic plasma

    International Nuclear Information System (INIS)

    Krommes, J.A.; Lee, W.W.; Oberman, C.

    1985-11-01

    The thermal equilibrium electric field fluctuation energy of the gyrokinetic model of magnetized plasma is computed, and found to be smaller than the well-known result (k)/8π = 1/2T/[1 + (klambda/sub D/) 2 ] valid for arbitrarily magnetized plasmas. It is shown that, in a certain sense, the equilibrium electric field energy is minimum in the gyrokinetic regime. 13 refs., 2 figs

  2. Thermalization vs. isotropization and azimuthal fluctuations

    International Nuclear Information System (INIS)

    Mrowczynski, Stanislaw

    2005-01-01

    Hydrodynamic description requires a local thermodynamic equilibrium of the system under study but an approximate hydrodynamic behaviour is already manifested when a momentum distribution of liquid components is not of equilibrium form but merely isotropic. While the process of equilibration is relatively slow, the parton system becomes isotropic rather fast due to the plasma instabilities. Azimuthal fluctuations observed in relativistic heavy-ion collisions are argued to distinguish between a fully equilibrated and only isotropic parton system produced in the collision early stage

  3. Fluctuation microscopy analysis of amorphous silicon models

    Energy Technology Data Exchange (ETDEWEB)

    Gibson, J.M., E-mail: jmgibson@fsu.edu [Northeastern University, Department of Physics, Boston MA 02115 (United States); FAMU/FSU Joint College of Engineering, 225 Pottsdamer Street, Tallahassee, FL 32310 (United States); Treacy, M.M.J. [Arizona State University, Department of Physics, Tempe AZ 85287 (United States)

    2017-05-15

    Highlights: • Studied competing computer models for amorphous silicon and simulated fluctuation microscopy data. • Show that only paracrystalline/random network composite can fit published data. • Specifically show that pure random network or random network with void models do not fit available data. • Identify a new means to measure volume fraction of ordered material. • Identify unreported limitations of the Debye model for simulating fluctuation microscopy data. - Abstract: Using computer-generated models we discuss the use of fluctuation electron microscopy (FEM) to identify the structure of amorphous silicon. We show that a combination of variable resolution FEM to measure the correlation length, with correlograph analysis to obtain the structural motif, can pin down structural correlations. We introduce the method of correlograph variance as a promising means of independently measuring the volume fraction of a paracrystalline composite. From comparisons with published data, we affirm that only a composite material of paracrystalline and continuous random network that is substantially paracrystalline could explain the existing experimental data, and point the way to more precise measurements on amorphous semiconductors. The results are of general interest for other classes of disordered materials.

  4. Pressure fluctuation caused by moderate acceleration

    Science.gov (United States)

    Tagawa, Yoshiyuki; Kurihara, Chihiro; Kiyama, Akihito

    2017-11-01

    Pressure fluctuation caused by acceleration of a liquid column is observed in various important technologies, e.g. water-hammer in a pipeline. The magnitude of fluctuation can be estimated by two different approaches: When the duration time of acceleration is much shorter than the propagation time for a pressure wave to travel the length of the liquid column, e.g. sudden valve closure for a long pipe, Joukowsky equation is applied. In contrast, if the acceleration duration is much longer, the liquid is modeled as a rigid column, ignoring compressibility of the fluid. However, many of practical cases exist between these two extremes. In this study we propose a model describing pressure fluctuation when the duration of acceleration is in the same order of the propagation time for a pressure wave, i.e. under moderate acceleration. The novel model considers both temporal and spatial evolutions of pressure propagation as well as gradual pressure rise during the acceleration. We conduct experiments in which we impose acceleration to a liquid with varying the length of the liquid column, acceleration duration, and properties of liquids. The ratio between the acceleration duration and the propagation time is in the range of 0.02 - 2. The model agrees well with measurement results. JSPS KAKENHI Grant Numbers 26709007 and 17H01246.

  5. Fluctuations in the DNA double helix

    Science.gov (United States)

    Peyrard, M.; López, S. C.; Angelov, D.

    2007-08-01

    DNA is not the static entity suggested by the famous double helix structure. It shows large fluctuational openings, in which the bases, which contain the genetic code, are temporarily open. Therefore it is an interesting system to study the effect of nonlinearity on the physical properties of a system. A simple model for DNA, at a mesoscopic scale, can be investigated by computer simulation, in the same spirit as the original work of Fermi, Pasta and Ulam. These calculations raise fundamental questions in statistical physics because they show a temporary breaking of equipartition of energy, regions with large amplitude fluctuations being able to coexist with regions where the fluctuations are very small, even when the model is studied in the canonical ensemble. This phenomenon can be related to nonlinear excitations in the model. The ability of the model to describe the actual properties of DNA is discussed by comparing theoretical and experimental results for the probability that base pairs open an a given temperature in specific DNA sequences. These studies give us indications on the proper description of the effect of the sequence in the mesoscopic model.

  6. Large fluctuations and fixation in evolutionary games

    International Nuclear Information System (INIS)

    Assaf, Michael; Mobilia, Mauro

    2010-01-01

    We study large fluctuations in evolutionary games belonging to the coordination and anti-coordination classes. The dynamics of these games, modeling cooperation dilemmas, is characterized by a coexistence fixed point separating two absorbing states. We are particularly interested in the problem of fixation that refers to the possibility that a few mutants take over the entire population. Here, the fixation phenomenon is induced by large fluctuations and is investigated by a semiclassical WKB (Wentzel–Kramers–Brillouin) theory generalized to treat stochastic systems possessing multiple absorbing states. Importantly, this method allows us to analyze the combined influence of selection and random fluctuations on the evolutionary dynamics beyond the weak selection limit often considered in previous works. We accurately compute, including pre-exponential factors, the probability distribution function in the long-lived coexistence state and the mean fixation time necessary for a few mutants to take over the entire population in anti-coordination games, and also the fixation probability in the coordination class. Our analytical results compare excellently with extensive numerical simulations. Furthermore, we demonstrate that our treatment is superior to the Fokker–Planck approximation when the selection intensity is finite

  7. Edge plasma fluctuations in STOR-M

    International Nuclear Information System (INIS)

    Zhang, W.; Hirose, A.; Zhang, L.; Xiao, C.; Conway, G.D.; Skarsgard, H.M.

    1993-01-01

    In the STOR-M tokamak, the coherence and propagation nature of the density (n e ) and magnetic (B r ) fluctuations are investigated both in the scrape-off layer (SOL, r/a > 1) and at the plasma edge (r/a -2 is of the order of the reverse electron skin depth kθ ≅ ω pe /c. In terms of the hybrid ion Larmor radius ρ s = c s /Ω i , it corresponds to k θρ s ≅ 0.1. These observations support the skin size electromagnetic drift mode which predicts that a low β tokamak discharge is unstable against the skin size electromagnetic instability with a phase velocity significantly smaller than the electron diamagnetic drift velocity. Edge fluctuations observed in STOR-M appear to propagate at the local E x B drift, and the phase velocity in the plasma from is υ theta ≅ 5 x 10 4 cm/sec, compared with the local electron diamagnetic drift, υ e ≅ 2.5 x 10 5 cm/sec. In the SOL region, the density fluctuations propagate in the ion diamagnetic drift, but still with the local E x B drift because E r changes its sign at r/a ≅ 1

  8. Water-level fluctuations influence sediment porewater ...

    Science.gov (United States)

    Reservoirs typically have elevated fish mercury (Hg) levels compared to natural lakes and rivers. A unique feature of reservoirs is water-level management which can result in sediment exposure to the air. The objective of this study is to identify how reservoir water-level fluctuations impact Hg cycling, particularly the formation of the more toxic and bioaccumulative methylmercury (MeHg). Total-Hg (THg), MeHg, stable isotope methylation rates and several ancillary parameters were measured in reservoir sediments (including some in porewater and overlying water) that are seasonally and permanently inundated. The results showed that sediment and porewater MeHg concentrations were over 3-times higher in areas experiencing water-level fluctuations compared to permanently inundated sediments. Analysis of the data suggest that the enhanced breakdown of organic matter in sediments experiencing water-level fluctuations has a two-fold effect on stimulating Hg methylation: 1) it increases the partitioning of inorganic Hg from the solid phase into the porewater phase (lower log Kd values) where it is more bioavailable for methylation; and 2) it increases dissolved organic carbon (DOC) in the porewater which can stimulate the microbial community that can methylate Hg. Sulfate concentrations and cycling were enhanced in the seasonally inundated sediments and may have also contributed to increased MeHg production. Overall, our results suggest that reservoir management a

  9. Turbulent temperature fluctuations in liquid metals

    International Nuclear Information System (INIS)

    Lawn, C.J.

    1977-01-01

    Examination of experimental data for the spectral distribution of velocity (u and v) and temperature (theta) fluctuations in the fully turbulent region of heated pipe-flow has suggested a schematic representation which incorporates the essential features. Evidence is cited to suggest that the -vtheta correlation coefficient maintains higher values that the uv coefficient at wave-numbers in the inertial subrange. The theory of Batchelor, Howells and Townsend, and limited evidence from experiments in mercury, then suggests the form of the theta 2 spectra and -vtheta cross-spectra in liquid metals. From this information, a limiting Peclet number is deduced, above which the correlation coefficient of v and theta should be a fairly weak function of Pe alone. An attempt to check this inference from published data for the RMS level of temperature fluctuations, and for the turbulent Prandtl number, proves inconclusive, because many of the correlation coefficients so estimated have values greater than unity. It is concluded that all these results for theta tilde must therefore be in error. However, since there is no evidence of very low correlation coefficients, they almost certainly lie in the range 0.5 multiply/divide 2 over a large proportion of the radius. Thus theta tilde can be estimated for any fluid in which the fluctuations are induced by uniform heating, at least to within a factor of 2, using the analysis presented. (author)

  10. Fluctuation microscopy analysis of amorphous silicon models

    International Nuclear Information System (INIS)

    Gibson, J.M.; Treacy, M.M.J.

    2017-01-01

    Highlights: • Studied competing computer models for amorphous silicon and simulated fluctuation microscopy data. • Show that only paracrystalline/random network composite can fit published data. • Specifically show that pure random network or random network with void models do not fit available data. • Identify a new means to measure volume fraction of ordered material. • Identify unreported limitations of the Debye model for simulating fluctuation microscopy data. - Abstract: Using computer-generated models we discuss the use of fluctuation electron microscopy (FEM) to identify the structure of amorphous silicon. We show that a combination of variable resolution FEM to measure the correlation length, with correlograph analysis to obtain the structural motif, can pin down structural correlations. We introduce the method of correlograph variance as a promising means of independently measuring the volume fraction of a paracrystalline composite. From comparisons with published data, we affirm that only a composite material of paracrystalline and continuous random network that is substantially paracrystalline could explain the existing experimental data, and point the way to more precise measurements on amorphous semiconductors. The results are of general interest for other classes of disordered materials.

  11. Local polar fluctuations in lead halide perovskites

    Science.gov (United States)

    Tan, Liang; Yaffe, Omer; Guo, Yinsheng; Brus, Louis; Rappe, Andrew; Egger, David; Kronik, Leeor

    The lead halide perovskites have recently attracted much attention because of their large and growing photovoltaic power conversion efficiencies. However, questions remain regarding the temporal and spatial correlations of the structural fluctuations, their atomistic nature, and how they affect electronic and photovoltaic properties. To address these questions, we have performed a combined ab initio molecular dynamics (MD) and density functional theory (DFT) study on CsPbBr3. We have observed prevalent anharmonic motion in our MD trajectories, with local polar fluctuations involving head-to-head motion of A-site Cs cations coupled with Br window opening. We calculate Raman spectra from the polarizability auto-correlation functions obtained from these trajectories and show that anharmonic A-site cation motion manifests as a broad central peak in the Raman spectrum, which increases in intensity with temperature. A comparison of the experimental Raman spectrum of hybrid organometallic MAPbBr3 and fully inorganic CsPbBr3 suggests that structural fluctuations in lead-halide perovskites is more general than rotation of polar organic cations and is intimately coupled to the inorganic framework.

  12. Dynamic Model and Vibration Power Flow of a Rigid-Flexible Coupling and Harmonic-Disturbance Exciting System for Flexible Robotic Manipulator with Elastic Joints

    Directory of Open Access Journals (Sweden)

    Yufei Liu

    2015-01-01

    Full Text Available This paper investigates the dynamic of a flexible robotic manipulator (FRM which consists of rigid driving base, flexible links, and flexible joints. With considering the motion fluctuations caused by the coupling effect, such as the motor parameters and mechanism inertias, as harmonic disturbances, the system investigated in this paper remains a parametrically excited system. An elastic restraint model of the FRM with elastic joints (FRMEJ is proposed, which considers the elastic properties of the connecting joints between the flexible arm and the driving base, as well as the harmonic disturbances aroused by the electromechanical coupling effect. As a consequence, the FRMEJ accordingly remains a flexible multibody system which conveys the effects of rigid-flexible couple and electromechanical couple. The Lagrangian function and Hamilton’s principle are used to establish the dynamic model of the FRMEJ. Based on the dynamic model proposed, the vibration power flow is introduced to show the vibration energy distribution. Numerical simulations are conducted to investigate the effect of the joint elasticities and the disturbance excitations, and the influences of the structure parameters and motion parameters on the vibration power flow are studied. The results obtained in this paper contribute to the structure design, motion optimization, and vibration control of FRMs.

  13. Nuclear quantum effects and hydrogen bond fluctuations in water

    Science.gov (United States)

    Ceriotti, Michele; Cuny, Jérôme; Parrinello, Michele; Manolopoulos, David E.

    2013-01-01

    The hydrogen bond (HB) is central to our understanding of the properties of water. However, despite intense theoretical and experimental study, it continues to hold some surprises. Here, we show from an analysis of ab initio simulations that take proper account of nuclear quantum effects that the hydrogen-bonded protons in liquid water experience significant excursions in the direction of the acceptor oxygen atoms. This generates a small but nonnegligible fraction of transient autoprotolysis events that are not seen in simulations with classical nuclei. These events are associated with major rearrangements of the electronic density, as revealed by an analysis of the computed Wannier centers and 1H chemical shifts. We also show that the quantum fluctuations exhibit significant correlations across neighboring HBs, consistent with an ephemeral shuttling of protons along water wires. We end by suggesting possible implications for our understanding of how perturbations (solvated ions, interfaces, and confinement) might affect the HB network in water. PMID:24014589

  14. Local fluctuations of the signed traded volumes and the dependencies of demands: a copula analysis

    Science.gov (United States)

    Wang, Shanshan; Guhr, Thomas

    2018-03-01

    We investigate how the local fluctuations of the signed traded volumes affect the dependence of demands between stocks. We analyze the empirical dependence of demands using copulas and show that they are well described by a bivariate K copula density function. We find that large local fluctuations strongly increase the positive dependence but lower slightly the negative one in the copula density. This interesting feature is due to cross-correlations of volume imbalances between stocks. Also, we explore the asymmetries of tail dependencies of the copula density, which are moderate for the negative dependencies but strong for the positive ones. For the latter, we reveal that large local fluctuations of the signed traded volumes trigger stronger dependencies of demands than of supplies, probably indicating a bull market with persistent raising of prices.

  15. Mesoscopic fluctuations of the population of a qubit in a strong alternating field

    Energy Technology Data Exchange (ETDEWEB)

    Denisenko, M. V., E-mail: mar.denisenko@gmail.com; Satanin, A. M. [Lobachevsky State University of Nizhny Novgorod (Russian Federation)

    2016-12-15

    Fluctuations of the population of a Josephson qubit in an alternating field, which is a superposition of electromagnetic pulses with large amplitudes, are studied. It is shown that the relative phase of pulses is responsible for the rate of Landau–Zener transitions and, correspondingly, for the frequency of transitions between adiabatic states. The durations of pulses incident on the qubit are controlled with an accuracy of the field period, which results in strong mesoscopic fluctuations of the population of the qubit. Similar to the magnetic field in mesoscopic physics, the relative phase of pulses can destroy the interference pattern of the population of the qubit. The influence of the duration of the pulse and noise on the revealed fluctuation effects is studied.

  16. Energy fluctuations in a biharmonically driven nonlinear system

    Indian Academy of Sciences (India)

    analyse the nature of work and heat fluctuations and show that the steady state fluctuation .... The above equation is the statement of the first law of thermodynamics and ..... One of the authors (AMJ) thanks DST, India for financial support.

  17. Recent results of studies of plasma fluctuations in stellarators by microwave scattering technique

    International Nuclear Information System (INIS)

    Skvortsova, N.N.; Batanov, G.M.; Kolik, L.V.; Petrov, A.E.; Pshenichnikov, A.A.; Sarksyan, K.A.; Kharchev, N.K.; Khol'nov, Yu.V.; Kubo, S.; Sanchez, J.

    2005-01-01

    Microwave scattering diagnostics are described that allow direct measurements of the turbulent processes in a high-temperature plasma of magnetic confinement systems. Plasma density fluctuations in the heating region of the L-2M stellarator were measured from microwave scattering at the fundamental and the second harmonics of the heating gyrotron radiation. In the TJ-II stellarator, a separate 2-mm microwave source was used to produce a probing beam; the measurements were performed at the middle of the plasma radius. Plasma density fluctuations in the axial (heating) region of the LHD stellarator were measured from microwave scattering at the fundamental harmonic of the heating gyrotron radiation. Characteristic features of fluctuations, common for all three devices, are revealed with the methods of statistical and spectral analysis. These features are the wide frequency Fourier and wavelet spectra, autocorrelation functions with slowly decreasing tails, and non-Gaussian probability distributions of the magnitudes and the increments of the magnitude of fluctuations. The drift-dissipative instability and the instability driven by trapped electrons are examined as possible sources of turbulence in a high-temperature plasma. Observations showed the high level of coherence between turbulent fluctuations in the central region and at the edge of the plasma in L-2M. It is shown in L-2M that the relative intensity of the second harmonic of gyrotron radiation on the axis of a microwave beam after quasi-optical filtering in a four-mirror quasi-optical transmission line is about -50 dB of the total radiation intensity. Spatiotemporal structures in plasma density fluctuations were observed in the central region of the plasma column. The correlation time between the structures was found to be on the order of 1 ms. It is shown that, the spectrum of the signal from the second-harmonic scattering extends to higher frequencies in comparison with that from the fundamental

  18. Wearable Flexible Sensors: A Review

    KAUST Repository

    Nag, Anindya

    2017-05-18

    The paper provides a review on some of the significant research work done on wearable flexible sensors (WFS). Sensors fabricated with flexible materials have been attached to a person along with the embedded system to monitor a parameter and transfer the significant data to the monitoring unit for further analyses. The use of wearable sensors has played a quite important role to monitor physiological parameters of a person to minimize any malfunctioning happening in the body. The paper categorizes the work according to the materials used for designing the system, the network protocols and different types of activities that were being monitored. The challenges faced by the current sensing systems and future opportunities for the wearable flexible sensors regarding its market values are also briefly explained in the paper.

  19. Wearable Flexible Sensors: A Review

    KAUST Repository

    Nag, Anindya; Mukhopadhyay, Subhas Chandra; Kosel, Jü rgen

    2017-01-01

    The paper provides a review on some of the significant research work done on wearable flexible sensors (WFS). Sensors fabricated with flexible materials have been attached to a person along with the embedded system to monitor a parameter and transfer the significant data to the monitoring unit for further analyses. The use of wearable sensors has played a quite important role to monitor physiological parameters of a person to minimize any malfunctioning happening in the body. The paper categorizes the work according to the materials used for designing the system, the network protocols and different types of activities that were being monitored. The challenges faced by the current sensing systems and future opportunities for the wearable flexible sensors regarding its market values are also briefly explained in the paper.

  20. Living in a Flexible Space

    Science.gov (United States)

    Canepa, Simona

    2017-10-01

    How long does a space or an object have to last? If in the past an object or a building manufacturing was designed to last as much as possible, nowadays it is designed to have a life related to the time in which it will be used. Flexibility is what characterizes a space, it’s the ability to be variable and adaptable to changes in the lives of users or in relation to the use which these will make over time. The evolution of the labour market, the difficulty of inserting within it and the need to push more and more frequent move today in the trial of living space models increasingly flexible: people, especially young people, are forced to move on territory outlining a new condition to which the flexible nomadic dwellings offer an adequate response, ensuring high functional performance in confined spaces.