Multisensor integration and image recognition using Fuzzy Adaptive Resonance Theory
Singer, Steven M.
1997-04-01
The main objective of this work was to investigate the use of 'sensor based real time decision and control technology' applied to actively control the arrestment of aircraft (manned or unmanned). The proposed method is to develop an adaptively controlled system that would locate the aircraft's extended tailhook, predict its position and speed at the time of arrestment, adjust an arresting end effector to actively mate with the arresting hook and remove the aircraft's kinetic energy, thus minimizing the arresting distance and impact stresses. The focus of the work presented in this paper was to explore the use of fuzzy adaptive resonance theorem (fuzzy art) neural network to form a MSI scheme which reduces image data to recognize incoming aircraft and extended tailhook. Using inputs from several image sources a single fused image was generated to give details about range and tailhook characteristics for an F18 naval aircraft. The idea is to partition an image into cells and evaluate each using fuzzy art. Once the incoming aircraft is located in a cell that subimage is again divided into smaller cells. This image is evaluated to locate various parts of the aircraft (i.e., wings, tail, tailhook, etc.). the cell that contains the tailhook provides resolved position information. Multiple images from separate sensors provides opportunity to generate range details overtime.
Chang, H.-C.; Kopaska-Merkel, D. C.; Chen, H.-C.; Rocky, Durrans S.
2000-01-01
Lithofacies identification supplies qualitative information about rocks. Lithofacies represent rock textures and are important components of hydrocarbon reservoir description. Traditional techniques of lithofacies identification from core data are costly and different geologists may provide different interpretations. In this paper, we present a low-cost intelligent system consisting of three adaptive resonance theory neural networks and a rule-based expert system to consistently and objectively identify lithofacies from well-log data. The input data are altered into different forms representing different perspectives of observation of lithofacies. Each form of input is processed by a different adaptive resonance theory neural network. Among these three adaptive resonance theory neural networks, one neural network processes the raw continuous data, another processes categorial data, and the third processes fuzzy-set data. Outputs from these three networks are then combined by the expert system using fuzzy inference to determine to which facies the input data should be assigned. Rules are prioritized to emphasize the importance of firing order. This new approach combines the learning ability of neural networks, the adaptability of fuzzy logic, and the expertise of geologists to infer facies of the rocks. This approach is applied to the Appleton Field, an oil field located in Escambia County, Alabama. The hybrid intelligence system predicts lithofacies identity from log data with 87.6% accuracy. This prediction is more accurate than those of single adaptive resonance theory networks, 79.3%, 68.0% and 66.0%, using raw, fuzzy-set, and categorical data, respectively, and by an error-backpropagation neural network, 57.3%. (C) 2000 Published by Elsevier Science Ltd. All rights reserved.
ARTgrid: A Two-Level Learning Architecture Based on Adaptive Resonance Theory
Directory of Open Access Journals (Sweden)
Marko Švaco
2014-01-01
Full Text Available This paper proposes a novel neural network architecture based on adaptive resonance theory (ART called ARTgrid that can perform both online and offline clustering of 2D object structures. The main novelty of the proposed architecture is a two-level categorization and search mechanism that can enhance computation speed while maintaining high performance in cases of higher vigilance values. ARTgrid is developed for specific robotic applications for work in unstructured environments with diverse work objects. For that reason simulations are conducted on random generated data which represents actual manipulation objects, that is, their respective 2D structures. ARTgrid verification is done through comparison in clustering speed with the fuzzy ART algorithm and Adaptive Fuzzy Shadow (AFS network. Simulation results show that by applying higher vigilance values (ρ>0.85 clustering performance of ARTgrid is considerably better, while lower vigilance values produce comparable results with the original fuzzy ART algorithm.
Hand movements classification for myoelectric control system using adaptive resonance theory.
Jahani Fariman, H; Ahmad, Siti A; Hamiruce Marhaban, M; Alijan Ghasab, M; Chappell, Paul H
2016-03-01
This research proposes an exploratory study of a simple, accurate, and computationally efficient movement classification technique for prosthetic hand application. Surface myoelectric signals were acquired from the four muscles, namely, flexor carpi ulnaris, extensor carpi radialis, biceps brachii, and triceps brachii, of four normal-limb subjects. The signals were segmented, and the features were extracted with a new combined time-domain feature extraction method. Fuzzy C-means clustering method and scatter plot were used to evaluate the performance of the proposed multi-feature versus Hudgins' multi-feature. The movements were classified with a hybrid Adaptive Resonance Theory-based neural network. Comparative results indicate that the proposed hybrid classifier not only has good classification accuracy (89.09%) but also a significantly improved computation time.
Directory of Open Access Journals (Sweden)
Budhitama Subagdja
2016-06-01
Full Text Available One of the fundamental challenges in reinforcement learning is to setup a proper balance between exploration and exploitation to obtain the maximum cummulative reward in the long run. Most protocols for exploration bound the overall values to a convergent level of performance. If new knowledge is inserted or the environment is suddenly changed, the issue becomes more intricate as the exploration must compromise the pre-existing knowledge. This paper presents a type of multi-channel adaptive resonance theory (ART neural network model called fusion ART which serves as a fuzzy approximator for reinforcement learning with inherent features that can regulate the exploration strategy. This intrinsic regulation is driven by the condition of the knowledge learnt so far by the agent. The model offers a stable but incremental reinforcement learning that can involve prior rules as bootstrap knowledge for guiding the agent to select the right action. Experiments in obstacle avoidance and navigation tasks demonstrate that in the configuration of learning wherein the agent learns from scratch, the inherent exploration model in fusion ART model is comparable to the basic E-greedy policy. On the other hand, the model is demonstrated to deal with prior knowledge and strike a balance between exploration and exploitation.
Applied neutron resonance theory
International Nuclear Information System (INIS)
Froehner, F.H.
1978-07-01
Utilisation of resonance theory in basic and applications-oriented neutron cross section work is reviewed. The technically important resonance formalisms, principal concepts and methods as well as representative computer programs for resonance parameter extraction from measured data, evaluation of resonance data, calculation of Doppler-broadened cross sections and estimation of level-statistical quantities from resonance parameters are described. (orig.) [de
Li, Pu; Chen, Bing; Li, Zelin; Zheng, Xiao; Wu, Hongjing; Jing, Liang; Lee, Kenneth
2014-09-15
In this paper, a Monte Carlo simulation based two-stage adaptive resonance theory mapping (MC-TSAM) model was developed to classify a given site into distinguished zones representing different levels of offshore Oil Spill Vulnerability Index (OSVI). It consisted of an adaptive resonance theory (ART) module, an ART Mapping module, and a centroid determination module. Monte Carlo simulation was integrated with the TSAM approach to address uncertainties that widely exist in site conditions. The applicability of the proposed model was validated by classifying a large coastal area, which was surrounded by potential oil spill sources, based on 12 features. Statistical analysis of the results indicated that the classification process was affected by multiple features instead of one single feature. The classification results also provided the least or desired number of zones which can sufficiently represent the levels of offshore OSVI in an area under uncertainty and complexity, saving time and budget in spill monitoring and response. Copyright © 2014 Elsevier Ltd. All rights reserved.
International Nuclear Information System (INIS)
Cai, Yuan; Wang, Jian-zhou; Tang, Yun; Yang, Yu-chen
2011-01-01
This paper presents a neural network based on adaptive resonance theory, named distributed ART (adaptive resonance theory) and HS-ARTMAP (Hyper-spherical ARTMAP network), applied to the electric load forecasting problem. The distributed ART combines the stable fast learning capabilities of winner-take-all ART systems with the noise tolerance and code compression capabilities of multi-layer perceptions. The HS-ARTMAP, a hybrid of an RBF (Radial Basis Function)-network-like module which uses hyper-sphere basis function substitute the Gaussian basis function and an ART-like module, performs incremental learning capabilities in function approximation problem. The HS-ARTMAP only receives the compressed distributed coding processed by distributed ART to deal with the proliferation problem which ARTMAP (adaptive resonance theory map) architecture often encounters and still performs well in electric load forecasting. To demonstrate the performance of the methodology, data from New South Wales and Victoria in Australia are illustrated. Results show that the developed method is much better than the traditional BP and single HS-ARTMAP neural network. -- Research highlights: → The processing of the presented network is based on compressed distributed data. It's an innovation among the adaptive resonance theory architecture. → The presented network decreases the proliferation the Fuzzy ARTMAP architectures usually encounter. → The network on-line forecasts electrical load accurately, stably. → Both one-period and multi-period load forecasting are executed using data of different cities.
Neutron resonance absorption theory
International Nuclear Information System (INIS)
Reuss, P.
1991-11-01
After some recalls on the physics of neutron resonance absorption during their slowing down, this paper presents the main features of the theoretical developments performed by the french school of reactor physics: the effective reaction rate method so called Livolant-Jeanpierre theory, the generalizations carried out by the author, and the probability table method [fr
Giant resonances: reaction theory approach
International Nuclear Information System (INIS)
Toledo Piza, A.F.R. de; Foglia, G.A.
1989-09-01
The study of giant resonances through the use of reaction theory approach is presented and discussed. Measurements of cross-sections to the many available decay channels following excitation of giant multipole resonances (GMR) led one to view these phenomena as complicated dynamical syndromes so that theoretical requirements for their study must be extended beyond the traditional bounds of nuclear structure models. The spectra of decay products following GMR excitation in heavy nuclei are well described by statistical model (Hauser-Feshback, HF) predictions indicated that spreading of the collective modes plays a major role in shaping exclusive cross-sections. (A.C.A.S.) [pt
Energy Technology Data Exchange (ETDEWEB)
Jones, Christian Birk [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Photovoltaic and Grid Integration Group; Robinson, Matt [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Mechanical Engineering; Yasaei, Yasser [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering; Caudell, Thomas [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering; Martinez-Ramon, Manel [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering; Mammoli, Andrea [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Mechanical Engineering
2016-07-01
Optimal integration of thermal energy storage within commercial building applications requires accurate load predictions. Several methods exist that provide an estimate of a buildings future needs. Methods include component-based models and data-driven algorithms. This work implemented a previously untested algorithm for this application that is called a Laterally Primed Adaptive Resonance Theory (LAPART) artificial neural network (ANN). The LAPART algorithm provided accurate results over a two month period where minimal historical data and a small amount of input types were available. These results are significant, because common practice has often overlooked the implementation of an ANN. ANN have often been perceived to be too complex and require large amounts of data to provide accurate results. The LAPART neural network was implemented in an on-line learning manner. On-line learning refers to the continuous updating of training data as time occurs. For this experiment, training began with a singe day and grew to two months of data. This approach provides a platform for immediate implementation that requires minimal time and effort. The results from the LAPART algorithm were compared with statistical regression and a component-based model. The comparison was based on the predictions linear relationship with the measured data, mean squared error, mean bias error, and cost savings achieved by the respective prediction techniques. The results show that the LAPART algorithm provided a reliable and cost effective means to predict the building load for the next day.
Laterally Primed Adaptive Resonance Theory
Energy Technology Data Exchange (ETDEWEB)
2017-07-19
LAPART is an artificial neural network algorithm written in the Python programming language. The algorithm can learn patterns using multi-dimensional hyper boxes. It can also perfrom regression and classification calculations based on learned associations.
Theory of coherent resonance energy transfer
International Nuclear Information System (INIS)
Jang, Seogjoo; Cheng, Y.-C.; Reichman, David R.; Eaves, Joel D.
2008-01-01
A theory of coherent resonance energy transfer is developed combining the polaron transformation and a time-local quantum master equation formulation, which is valid for arbitrary spectral densities including common modes. The theory contains inhomogeneous terms accounting for nonequilibrium initial preparation effects and elucidates how quantum coherence and nonequilibrium effects manifest themselves in the coherent energy transfer dynamics beyond the weak resonance coupling limit of the Foerster and Dexter (FD) theory. Numerical tests show that quantum coherence can cause significant changes in steady state donor/acceptor populations from those predicted by the FD theory and illustrate delicate cooperation of nonequilibrium and quantum coherence effects on the transient population dynamics.
Neutron resonance theory for safety applications
International Nuclear Information System (INIS)
Froehner, F.H.
1998-01-01
Neutron resonances exert a strong influence on the behaviour of nuclear reactors, especially on their response to the temperature changes accompanying power excursions, and also on the efficiency of shielding materials. The relevant theory of neutron resonance cross sections is reviewed, both for the resolved and the unresolved resonance region, with special emphasis on the technologically important approximations. Numerical techniques for Doppler broadening of resonances are presented, and the construction of group cross sections and self-shielding factors for neutronics calculations is outlined. (author)
Resonance and aspect matched adaptive radar (RAMAR)
Barrett, Terence William
2012-01-01
The book describes a new form of radar for which the target response is frequency, i.e., resonance-dependent. The book provides both prototype designs and empirical results collected from a variety of targets. The new form of radar, called RAMAR (Resonance and Aspect Matched Adaptive Radar) advances radar - mere ranging and detection - to the level of RF spectroscopy, and permits an advance of spectroscopic methods from optical, through infra-red and into the RF spectral range. The book will describe how a target's response can be a function of frequency components in the transmitted signal's
Giant dipole resonance by many levels theory
International Nuclear Information System (INIS)
Mondaini, R.P.
1977-01-01
The many levels theory is applied to photonuclear effect, in particular, in giant dipole resonance. A review about photonuclear dipole absorption, comparing with atomic case is done. The derivation of sum rules; their modifications by introduction of the concepts of effective charges and mass and the Siegert theorem. The experimental distributions are compared with results obtained by curve adjustment. (M.C.K.) [pt
Time dependent resonating Hartree-Bogoliubov theory
International Nuclear Information System (INIS)
Nishiyama, Seiya; Fukutome, Hideo.
1989-01-01
Very recently, we have developed a theory of excitations in superconducting Fermion systems with large quantum fluctuations that can be described by resonance of time dependent non-orthogonal Hartree-Bogoliubov (HB) wave functions with different correlation structures. We have derived a new kind of variation equation called the time dependent Resonating HB equation, in order to determine both the time dependent Resonating HB wave functions and coefficients of a superposition of the HB wave functions. Further we have got a new approximation for excitations from time dependent small fluctuations of the Resonating HB ground state, i.e., the Resonating HB RPA. The Res HB RPA equation is represented in a given single particle basis. It, however, has drawbacks that the constraints for the Res HB RPA amplitudes are not taken into account and the equation contains equations which are not independent. We shall derive another form of the Res HB RPA equation eliminating these drawbacks. The Res HB RPA gives a unified description of the vibrons and resonons and their interactions. (author)
Adaptive speciation theory : A conceptual review
Weissing, Franz J.; Edelaar, Pim; van Doorn, G. Sander
Speciation-the origin of new species-is the source of the diversity of life. A theory of speciation is essential to link poorly understood macro-evolutionary processes, such as the origin of biodiversity and adaptive radiation, to well understood micro-evolutionary processes, such as allele
Adaptive Core Simulation Employing Discrete Inverse Theory - Part I: Theory
International Nuclear Information System (INIS)
Abdel-Khalik, Hany S.; Turinsky, Paul J.
2005-01-01
Use of adaptive simulation is intended to improve the fidelity and robustness of important core attribute predictions such as core power distribution, thermal margins, and core reactivity. Adaptive simulation utilizes a selected set of past and current reactor measurements of reactor observables, i.e., in-core instrumentation readings, to adapt the simulation in a meaningful way. A meaningful adaption will result in high-fidelity and robust adapted core simulator models. To perform adaption, we propose an inverse theory approach in which the multitudes of input data to core simulators, i.e., reactor physics and thermal-hydraulic data, are to be adjusted to improve agreement with measured observables while keeping core simulator models unadapted. At first glance, devising such adaption for typical core simulators with millions of input and observables data would spawn not only several prohibitive challenges but also numerous disparaging concerns. The challenges include the computational burdens of the sensitivity-type calculations required to construct Jacobian operators for the core simulator models. Also, the computational burdens of the uncertainty-type calculations required to estimate the uncertainty information of core simulator input data present a demanding challenge. The concerns however are mainly related to the reliability of the adjusted input data. The methodologies of adaptive simulation are well established in the literature of data adjustment. We adopt the same general framework for data adjustment; however, we refrain from solving the fundamental adjustment equations in a conventional manner. We demonstrate the use of our so-called Efficient Subspace Methods (ESMs) to overcome the computational and storage burdens associated with the core adaption problem. We illustrate the successful use of ESM-based adaptive techniques for a typical boiling water reactor core simulator adaption problem
Chemical shift of neutron resonances and some ideas on neutron resonances and scattering theory
International Nuclear Information System (INIS)
Ignatovich, V.K.; )
2002-01-01
The dependence of positions of neutron resonances in nuclei in condensed matter on chemical environment is considered. A possibility of theoretical description of neutron resonances, different from R-matrix theory is investigated. Some contradictions of standard scattering theory are discussed and a new approach without these contradictions is formulated [ru
Demographic evidence for adaptive theories of aging.
Mitteldorf, J J
2012-07-01
Pleiotropic theories for the evolutionary origins of senescence have been ascendant for forty years (see, for example, G. Williams (1957) Evolution, 11, 398-411; T. Kirkwood (1977) Nature, 270, 301-304), and it is not surprising that interpreters of demographic data seek to frame their results in this context. But some of that evidence finds a much more natural explanation in terms of adaptive aging. Here we re-interpret the 1997 results of the Centenarian Study in Boston, which found in their sample of centenarian women an excess of late childbearing. The finding was originally interpreted as a selection effect: a metabolic link between late menopause and longevity. But we demonstrate that this interpretation is statistically strained, and that the data in fact indicate a causal link: bearing a child late in life induces a metabolic response that promotes longevity. This conclusion directly contradicts some pleiotropic theories of aging that postulate a "cost of reproduction", and it supports theories of aging as an adaptive genetic program.
[Philosophical aspects of the theory of adaptation].
Aliakrinskiĭ, B S
1986-01-01
This paper discusses the general concepts of the problem of adaptation from the dialectic point of view which, according to F. Engels, is the most important pattern of thinking in natural sciences. Dialectics provides an analog and therefore a method for interpreting developmental processes, universal relationships in nature, transition from one area of research to another. From the point of view of dialectic laws adaptation acts as a contradictory process of habituation to various environments. The contradictory pattern of the adaptive process and its result is very distinct in terms of heredity and variability. A logical enlargement of the concept of adaptation is the transition to the study of homeostasis which is assumed to be its mechanism, a property which has developed in the course of evolution and fixed in heredity. This adaptive property is contradictory in its essence because homeostasis is a unity of stability and instability, a fluctuating constancy. In addition to the law of constancy of the inner melieu, there is a law of homeostatic deviations. This concept can be understood through an analysis of the system theory that includes a continuous variation and conservation of structure which indicates its ordered oscillation, that is, its rhythmicity. This clarifies the relationship between homeostasis and biological rhythmicity as a method of maintaining the former. Thus, a consistent analysis of the problem of adaptation can help identify transition from one area of research to another, specifically to the study of oscillatory processes in living systems, including such oscillatory processes that have characteristics of universality and necessity. Such processes are biological rhythms with a period of about 24 hours, that is, circadian rhythms.
Adaptively optimizing stochastic resonance in visual system
Yang, Tao
1998-08-01
Recent psychophysics experiment has showed that the noise strength could affect the perceived image quality. This work gives an adaptive process for achieving the optimal perceived image quality in a simple image perception array, which is a simple model of an image sensor. A reference image from memory is used for constructing a cost function and defining the optimal noise strength where the cost function gets its minimum point. The reference image is a binary image, which is used to define the background and the object. Finally, an adaptive algorithm is proposed for searching the optimal noise strength. Computer experimental results show that if the reference image is a thresholded version of the sub-threshold input image then the output of the sensor array gives an optimal output, in which the background and the object have the biggest contrast. If the reference image is different from a thresholded version of the sub-threshold input image then the output usually gives a sub-optimal contrast between the object and the background.
Theory of neutron resonance cross sections for safety applications
International Nuclear Information System (INIS)
Froehner, F.H.
1992-09-01
Neutron resonances exert a strong influence on the behaviour of nuclear reactors, especially on their response to the temperature changes accompanying power excursions, and also on the efficiency of shielding materials. The relevant theory of neutron resonance cross sections including the practically important approximations is reviewed, both for the resolved and the unresolved resonance region. Numerical techniques for Doppler broadening of resonances are presented, and the construction of group constants and especially of self-shielding factors for neutronics calculations is outlined. (orig.) [de
Theory of neutron resonance cross sections for safety applications
International Nuclear Information System (INIS)
Froehner, F.H.
1993-01-01
Neutron resonances exert a strong influence on the behaviour of nuclear reactors, especially on their response to the temperature changes accompanying power excursions, and also on the efficiency of shielding materials. The relevant theory of neutron resonance cross sections including the practically important approximations is reviewed, both for the resolved and the unresolved resonance region. Numerical techniques for Doppler broadening of resonance are presented, and the construction of group constants and especially of self-shielding factors for neutronics calculations is outlined. (author). 75 refs, 14 figs, 3 tabs
Continuous neutron slowing down theory applied to resonances
International Nuclear Information System (INIS)
Segev, M.
1977-01-01
Neutronic formalisms that discretize the neutron slowing down equations in large numerical intervals currently account for the bulk effect of resonances in a given interval by the narrow resonance approximation (NRA). The NRA reduces the original problem to an efficient numerical formalism through two assumptions: resonance narrowness with respect to the scattering bands in the slowing down equations and resonance narrowness with respect to the numerical intervals. Resonances at low energies are narrow neither with respect to the slowing down ranges nor with respect to the numerical intervals, which are usually of a fixed lethargy width. Thus, there are resonances to which the NRA is not applicable. To stay away from the NRA, the continuous slowing down (CSD) theory of Stacey was invoked. The theory is based on a linear expansion in lethargy of the collision density in integrals of the slowing down equations and had notable success in various problems. Applying CSD theory to the assessment of bulk resonance effects raises the problem of obtaining efficient quadratures for integrals involved in the definition of the so-called ''moderating parameter.'' The problem was solved by two approximations: (a) the integrals were simplified through a rationale, such that the correct integrals were reproduced for very narrow or very wide resonances, and (b) the temperature-broadened resonant line shapes were replaced by nonbroadened line shapes to enable analytical integration. The replacement was made in such a way that the integrated capture and scattering probabilities in each resonance were preserved. The resulting formalism is more accurate than the narrow-resonance formalisms and is equally as efficient
Modern Theory of Gratings Resonant Scattering: Analysis Techniques and Phenomena
Sirenko, Yuriy K
2010-01-01
Diffraction gratings are one of the most popular objects of analysis in electromagnetic theory. The requirements of applied optics and microwave engineering lead to many new problems and challenges for the theory of diffraction gratings, which force us to search for new methods and tools for their resolution. In Modern Theory of Gratings, the authors present results of the electromagnetic theory of diffraction gratings that will constitute the base of further development of this theory, which meet the challenges provided by modern requirements of fundamental and applied science. This volume covers: spectral theory of gratings (Chapter 1) giving reliable grounds for physical analysis of space-frequency and space-time transformations of the electromagnetic field in open periodic resonators and waveguides; authentic analytic regularization procedures (Chapter 2) that, in contradistinction to the traditional frequency-domain approaches, fit perfectly for the analysis of resonant wave scattering processes; paramet...
Rectangular dielectric resonator antennas theory and design
Yaduvanshi, Rajveer S
2016-01-01
This book covers resonating modes inside device and gives insights into antenna design, impedance and radiation patterns. It discusses how higher-order modes generation and control impact bandwidth and antenna gain. The text covers new approaches in antenna design by investigation hybrid modes, H_Z and E_Z fields available simultaneously, and analysis and modelling on modes with practical applications in antenna design. The book will be prove useful to students, researchers and professionals alike.
Wavelet and adaptive filtration of the nuclear magnetic resonance signal
Czech Academy of Sciences Publication Activity Database
Bartušek, Karel
2002-01-01
Roč. 11, - (2002), s. 13 - 18 ISSN 0862-9846. [Datastat'01. Brno, 27.08.2001-30.08.2001] R&D Projects: GA ČR GA102/96/1136; GA AV ČR IAA2065201 Institutional research plan: CEZ:AV0Z2065902 Keywords : Wavelet filtration * adaptive filtration * magnetic resonance signal Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering
The role of resonances in chiral perturbation theory
International Nuclear Information System (INIS)
Ecker, G.; Rafael, E. de
1988-09-01
The strong interactions of low-lying meson resonances (spin ≤ 1) with the octet of pseudoscalar mesons (π,Κ,η) are considered to lowest order in the derivative expansion of chiral SU(3). The resonance contributions to the coupling constants of the O(p 4 ) effective chiral lagrangian involving pseudoscalar fields only are determined. These low-energy coupling constants are found to be dominated by the resonance contributions. Although we do not treat the vector and axial-vector mesons as gauge bosons of local chiral symmetry, vector meson dominance emerges as a prominent result of our analysis. As a further application of chiral resonance couplings, we calculate the electromagnetic pion mass difference to lowest order in chiral perturbation theory with explicit resonance fields. 29 refs., 2 figs., 5 tabs. (Author)
Paths to Förster's resonance energy transfer (FRET) theory
Masters, B. R.
2014-02-01
Theodor Förster (1910-1974) developed a phenomenological theory of nonradiative resonance energy transfer which proved to be transformative in the fields of chemistry, biochemistry, and biology. This paper explores the experimental and the theoretical antecedents of Förster's theory of resonance energy transfer (FRET). Early studies of sensitized fluorescence, fluorescence depolarization, and photosynthesis demonstrated the phenomena of long-range energy transfer. At the same time physicists developed theoretical models which contained common physical mechanisms and parameters: oscillating dipoles as models for the atoms or molecules, dipole-dipole coupling for the interaction, and a distance R0 that is optimal for resonance energy transfer. Early theories predicted R0 that was too large as compared to experiments. Finally, in 1946 Förster developed a classical theory and in 1948 he developed a quantum mechanical theory; both theories predicted an inverse sixth power dependence of the rate of energy transfer and a R0 that agreed with experiments. This paper attempts to determine why Förster succeeded when the other theoreticians failed to develop the correct theory. The putative roles of interdisciplinary education and collaborative research are discussed. Furthermore, I explore the role of science journals and their specific audiences in the popularization of FRET to a broad interdisciplinary community.
Multifrequency Electron Paramagnetic Resonance Theory and Applications
Misra, Sushil K
2011-01-01
Filling the gap for a systematic, authoritative, and up-to-date review of this cutting-edge technique, this book covers both low and high frequency EPR, emphasizing the importance of adopting the multifrequency approach to study paramagnetic systems in full detail by using the EPR method. In so doing, it discusses not only the underlying theory and applications, but also all recent advances -- with a final section devoted to future perspectives.
Applying Adapted Big Five Teamwork Theory to Agile Software Development
Strode, Diane
2016-01-01
Teamwork is a central tenet of agile software development and various teamwork theories partially explain teamwork in that context. Big Five teamwork theory is one of the most influential teamwork theories, but prior research shows that the team leadership concept in this theory it is not applicable to agile software development. This paper applies an adapted form of Big Five teamwork theory to cases of agile software development. Three independent cases were drawn from a single organisation....
Stieltjes-moment-theory technique for calculating resonance width's
International Nuclear Information System (INIS)
Hazi, A.U.
1978-12-01
A recently developed method for calculating the widths of atomic and molecular resonances is reviewed. The method is based on the golden-rule definition of the resonance width, GAMMA(E). The method uses only square-integrable, L 2 , basis functions to describe both the resonant and the non-resonant parts of the scattering wave function. It employs Stieltjes-moment-theory techniques to extract a continuous approximation for the width discrete representation of the background continuum. Its implementation requires only existing atomic and molecular structure codes. Many-electron effects, such as correlation and polarization, are easily incorporated into the calculation of the width via configuration interaction techniques. Once the width, GAMMA(E), has been determined, the energy shift can be computed by a straightforward evaluation of the required principal-value integral. The main disadvantage of the method is that it provides only the total width of a resonance which decays into more than one channel in a multichannel problem. A review of the various aspects of the theory is given first, and then representative results that have been obtained with this method for several atomic and molecular resonances are discussed. 28 references, 3 figures, 4 tables
The early years of string theory: The dual resonance model
International Nuclear Information System (INIS)
Ramond, P.
1987-10-01
This paper reviews the past quantum mechanical history of the dual resonance model which is an early string theory. The content of this paper is listed as follows: historical review, the Veneziano amplitude, the operator formalism, the ghost story, and the string story
Multiple Literacies Theory: Discourse, Sensation, Resonance and Becoming
Masny, Diana
2012-01-01
This thematic issue on education and the politics of becoming focuses on how a Multiple Literacies Theory (MLT) plugs into practice in education. MLT does this by creating an assemblage between discourse, text, resonance and sensations. What does this produce? Becoming AND how one might live are the product of an assemblage (May, 2005; Semetsky,…
Coupled mode theory for resonant excitation of waveguiding structures
Hoekstra, Hugo
2000-01-01
Resonant coupling of light beams via high-index media or gratings to planar waveguiding structures are of interest for both applications and from a theoretical point of view. Coupled Mode theory (CMT) can give an accurate description of the coupling process in terms of relatively simple expressions
Theory of inelastic effects in resonant atom-surface scattering
International Nuclear Information System (INIS)
Evans, D.K.
1983-01-01
The progress of theoretical and experimental developments in atom-surface scattering is briefly reviewed. The formal theory of atom-surface resonant scattering is reviewed and expanded, with both S and T matrix approaches being explained. The two-potential formalism is shown to be useful for dealing with the problem in question. A detailed theory based on the S-matrix and the two-potential formalism is presented. This theory takes account of interactions between the incident atoms and the surface phonons, with resonant effects being displayed explicitly. The Debye-Waller attenuation is also studied. The case in which the atom-surface potential is divided into an attractive part V/sub a/ and a repulsive part V/sub r/ is considered at length. Several techniques are presented for handling the scattering due to V/sub r/, for the case in which V/sub r/ is taken to be the hard corrugated surface potential. The theory is used to calculate the scattered intensities for the system 4 He/LiF(001). A detailed comparison with experiment is made, with polar scans, azimuthal scans, and time-of-flight measurements being considered. The theory is seen to explain the location and signature of resonant features, and to provide reasonable overall agreement with the experimental results
Directory of Open Access Journals (Sweden)
Billy W. Day
2010-11-01
Full Text Available Biosensors have been used extensively in the scientific community for several purposes, most notably to determine association and dissociation kinetics, protein-ligand, protein-protein, or nucleic acid hybridization interactions. A number of different types of biosensors are available in the field, each with real or perceived benefits over the others. This review discusses the basic theory and operational arrangements of four commercially available types of optical biosensors: surface plasmon resonance, resonant mirror, resonance waveguide grating, and dual polarization interferometry. The different applications these techniques offer are discussed from experiments and results reported in recently published literature. Additionally, recent advancements or modifications to the current techniques are also discussed.
Synthetic Computation: Chaos Computing, Logical Stochastic Resonance, and Adaptive Computing
Kia, Behnam; Murali, K.; Jahed Motlagh, Mohammad-Reza; Sinha, Sudeshna; Ditto, William L.
Nonlinearity and chaos can illustrate numerous behaviors and patterns, and one can select different patterns from this rich library of patterns. In this paper we focus on synthetic computing, a field that engineers and synthesizes nonlinear systems to obtain computation. We explain the importance of nonlinearity, and describe how nonlinear systems can be engineered to perform computation. More specifically, we provide an overview of chaos computing, a field that manually programs chaotic systems to build different types of digital functions. Also we briefly describe logical stochastic resonance (LSR), and then extend the approach of LSR to realize combinational digital logic systems via suitable concatenation of existing logical stochastic resonance blocks. Finally we demonstrate how a chaotic system can be engineered and mated with different machine learning techniques, such as artificial neural networks, random searching, and genetic algorithm, to design different autonomous systems that can adapt and respond to environmental conditions.
Atomic many-body theory of giant resonances
International Nuclear Information System (INIS)
Kelly, H.P.; Altun, Z.
1987-01-01
In this paper the use of many-body perturbation theory (MBPT) to include effects of electron correlations is discussed. The various physical processes contributing to the broad photoionization cross sections of the rare gases are studied in terms of the relevant many-body diagrams. Use of the random phase approximation with exchange (RPAE) is discussed by Amusia and Cherepkov. Calculations using the relativistic RPAE are reviewed by Johnson. In addition, many-body perturbation theory (MBPT) is used to study resonances which are due to excitation of bound states degenerate with the continuum. Very interesting giant resonance structure can occur when an inner shell electron is excited into a vacant open-shell orbital of the same principal quantum number. A particular example which is studied is the neutral manganese atom 3p 6 3d 5 4s 2 ( 6 S), in which the spins of the five 3d electrons are aligned. A very large resonance occurs in the 3d and 4s cross sections due to 3p → 3d excitation near 51 eV, and calculations of this resonance by MBPT and RPAE are discussed. A second example of this type of resonance occurs in open-shell rare-earth atoms with configurations 4d 10 4f/sup n/5s 2 5p 6 s 2 . Calculations and experimental results will be discussed for the case of europium with a half-filled sub-shell 4f 7 . 71 references, 15 figures
Bilingual brain organization: a functional magnetic resonance adaptation study.
Klein, Denise; Zatorre, Robert J; Chen, Jen-Kai; Milner, Brenda; Crane, Joelle; Belin, Pascal; Bouffard, Marc
2006-05-15
We used functional magnetic resonance adaptation (fMRA) to examine whether intra-voxel functional specificity may be present for first (L1)- and second (L2)-language processing. We examined within- and across-language adaptation for spoken words in English-French bilinguals who had acquired their L2 after the age of 4 years. Subjects listened to words presented binaurally through earphones. In two control conditions (one for each language), six identical words were presented to obtain maximal adaptation. The remaining six conditions each consisted of five words that were identical followed by a sixth word that differed. There were thus a total of eight experimental conditions: no-change (sixth word identical to first five); a change in meaning (different final word in L1); a change in language (final item translated into L2); a change in meaning and language (different final word in L2). The same four conditions were presented in L2. The study also included a silent baseline. At the neural level, within- and across-language word changes resulted in release from adaptation. This was true for separate analyses of L1 and L2. We saw no evidence for greater recovery from adaptation in across-language relative to within-language conditions. While many brain regions were common to L1 and L2, we did observe differences in adaptation for forward translation (L1 to L2) as compared to backward translation (L2 to L1). The results support the idea that, at the lexical level, the neural substrates for L1 and L2 in bilinguals are shared, but with some populations of neurons within these shared regions showing language-specific responses.
Non-resonant energy harvesting via an adaptive bistable potential
International Nuclear Information System (INIS)
Hosseinloo, Ashkan Haji; Turitsyn, Konstantin
2016-01-01
Narrow bandwidth and easy detuning, inefficiency in broadband and non-stationary excitations, and difficulties in matching a linear harvester’s resonance frequency to low-frequency excitations at small scales, have convinced researchers to investigate nonlinear, and in particular bistable, energy harvesters in recent years. However, bistable harvesters suffer from co-existing low and high energy orbits, and sensitivity to initial conditions, and have recently been proven inefficient when subjected to many real-world random and non-stationary excitations. Here, we propose a novel non-resonant buy-low-sell-high strategy that can significantly improve the harvester’s effectiveness at low frequencies in a much more robust fashion. This strategy could be realized by a passive adaptive bistable system. Simulation results confirm the high effectiveness of the adaptive bistable system following a buy-low-sell-high logic when subjected to harmonic and random non-stationary walking excitations compared to its conventional bistable and linear counterparts. (paper)
Planetary gearbox fault diagnosis using an adaptive stochastic resonance method
Lei, Yaguo; Han, Dong; Lin, Jing; He, Zhengjia
2013-07-01
Planetary gearboxes are widely used in aerospace, automotive and heavy industry applications due to their large transmission ratio, strong load-bearing capacity and high transmission efficiency. The tough operation conditions of heavy duty and intensive impact load may cause gear tooth damage such as fatigue crack and teeth missed etc. The challenging issues in fault diagnosis of planetary gearboxes include selection of sensitive measurement locations, investigation of vibration transmission paths and weak feature extraction. One of them is how to effectively discover the weak characteristics from noisy signals of faulty components in planetary gearboxes. To address the issue in fault diagnosis of planetary gearboxes, an adaptive stochastic resonance (ASR) method is proposed in this paper. The ASR method utilizes the optimization ability of ant colony algorithms and adaptively realizes the optimal stochastic resonance system matching input signals. Using the ASR method, the noise may be weakened and weak characteristics highlighted, and therefore the faults can be diagnosed accurately. A planetary gearbox test rig is established and experiments with sun gear faults including a chipped tooth and a missing tooth are conducted. And the vibration signals are collected under the loaded condition and various motor speeds. The proposed method is used to process the collected signals and the results of feature extraction and fault diagnosis demonstrate its effectiveness.
Blade Crack Detection of Centrifugal Fan Using Adaptive Stochastic Resonance
Directory of Open Access Journals (Sweden)
Bingbing Hu
2015-01-01
Full Text Available Centrifugal fans are widely used in various industries as a kind of turbo machinery. Among the components of the centrifugal fan, the impeller is a key part because it is used to transform kinetic energy into pressure energy. Crack in impeller’s blades is one of the serious hidden dangers. It is important to detect the cracks in the blades as early as possible. Based on blade vibration signals, this research applies an adaptive stochastic resonance (ASR method to diagnose crack fault in centrifugal fan. The ASR method, which can utilize the optimization ability of the grid search method and adaptively realize the optimal stochastic resonance system matching input signals, may weaken the noise and highlight weak characteristic and thus can diagnose the fault accurately. A centrifugal fan test rig is established and experiments with three cases of blades are conducted. In comparison with the ensemble empirical mode decomposition (EEMD analysis and the traditional Fourier transform method, the experiment verified the effectiveness of the current method in blade crack detection.
Adaptive management of natural resources: theory, concepts, and management institutions.
George H. Stankey; Roger N. Clark; Bernard T. Bormann
2005-01-01
This report reviews the extensive and growing literature on the concept and application of adaptive management. Adaptive management is a central element of the Northwest Forest Plan and there is a need for an informed understanding of the key theories, concepts, and frameworks upon which it is founded. Literature from a diverse range of fields including social learning...
"Theory of food" as a neurocognitive adaptation.
Allen, John S
2012-01-01
Human adult cognition emerges over the course of development via the interaction of multiple critical neurocognitive networks. These networks evolved in response to various selection pressures, many of which were modified or intensified by the intellectual, technological, and sociocultural environments that arose in connection with the evolution of genus Homo. Networks related to language and theory of mind clearly play an important role in adult cognition. Given the critical importance of food to both basic survival and cultural interaction, a "theory of food" (analogous to theory of mind) may represent another complex network essential for normal cognition. I propose that theory of food evolved as an internal, cognitive representation of our diets in our minds. Like other complex cognitive abilities, it relies on complex and overlapping dedicated neural networks that develop in childhood under familial and cultural influences. Normative diets are analogous to first languages in that they are acquired without overt teaching; they are also difficult to change or modify once a critical period in development is passed. Theory of food suggests that cognitive activities related to food may be cognitive enhancers, which could have implications for maintaining healthy brain function in aging. Copyright © 2012 Wiley Periodicals, Inc.
Adaptive integral equation methods in transport theory
International Nuclear Information System (INIS)
Kelley, C.T.
1992-01-01
In this paper, an adaptive multilevel algorithm for integral equations is described that has been developed with the Chandrasekhar H equation and its generalizations in mind. The algorithm maintains good performance when the Frechet derivative of the nonlinear map is singular at the solution, as happens in radiative transfer with conservative scattering and in critical neutron transport. Numerical examples that demonstrate the algorithm's effectiveness are presented
Liu, Xiaole; Liu, Houguang; Yang, Jianhua; Litak, Grzegorz; Cheng, Gang; Han, Shuai
2017-11-01
It is a challenging task to detect the weak character signal in the noisy background. The stochastic resonance (SR) method has been wildly adopted recently because it can not only reduce the noise, but also enhance the weak feature information simultaneously. However, the traditional bistable model for SR is not perfect. So, this paper presents a new model with periodic potential to induce the adaptive SR. In the new model, based on the adaptive SR theory, the system parameters are simultaneously optimized by the improved artificial fish swarm algorithm. Meanwhile, the improved signal-to-noise ratio (ISNR) is set as the evaluation index. When the ISNR reaches a maximum, the output is optimal. In order to eliminate interference to obtain more useful information, the signals are preprocessed by Hilbert transform and High-pass filter before being input to the adaptive SR system. To verify the effectiveness of the proposed method, both numerical simulation and the vibration signal of the rolling element bearing from the lab experimental are adopted. Both of the results indicate that the adaptive SR model proposed shows better performance in weak character signals detection than the traditional adaptive SR in the bistable model. Meanwhile, the experimental signals with different working conditions are also processed by the new method. The results show that the method proposed could be more widely applied.
Adaptive Networks Theory, Models and Applications
Gross, Thilo
2009-01-01
With adaptive, complex networks, the evolution of the network topology and the dynamical processes on the network are equally important and often fundamentally entangled. Recent research has shown that such networks can exhibit a plethora of new phenomena which are ultimately required to describe many real-world networks. Some of those phenomena include robust self-organization towards dynamical criticality, formation of complex global topologies based on simple, local rules, and the spontaneous division of "labor" in which an initially homogenous population of network nodes self-organizes into functionally distinct classes. These are just a few. This book is a state-of-the-art survey of those unique networks. In it, leading researchers set out to define the future scope and direction of some of the most advanced developments in the vast field of complex network science and its applications.
The asymptotic theory of resonance charge exchange between diatomics
International Nuclear Information System (INIS)
Yevsyev, A.V.; Radtsig, A.A.; Smirnov, B.M.
1982-01-01
The asymptotic theory of resonance charge exchange between a ground-state diatomic molecular ion and its neutral parent is presented. The parameters of the valence electron wavefunction and asymptotically precise exchange interaction potential are calculated. The role of rotational transitions is discussed. The vibrational excitation transfer is taken into account and the coupled equations, describing the charge exchange process between diatomics are solved both in limiting cases and numerically. The total charge transfer cross sections are calculated for many diatomic systems and the results are compared with experimental data. (author)
Middle-Range Theory: Coping and Adaptation with Active Aging.
Salazar-Barajas, Martha Elba; Salazar-González, Bertha Cecilia; Gallegos-Cabriales, Esther Carlota
2017-10-01
Various disciplines focus on a multiplicity of aspects of aging: lifestyles, personal biological factors, psychological conditions, health conditions, physical environment, and social and economic factors. The aforementioned are all related to the determinants of active aging. The aim is to describe the development of a middle-range theory based on coping and adaptation with active aging. Concepts and relationships derived from Roy's model of adaptation are included. The proposed concepts are hope, health habits, coping with aging, social relations, and active aging.
Conformal prediction for reliable machine learning theory, adaptations and applications
Balasubramanian, Vineeth; Vovk, Vladimir
2014-01-01
The conformal predictions framework is a recent development in machine learning that can associate a reliable measure of confidence with a prediction in any real-world pattern recognition application, including risk-sensitive applications such as medical diagnosis, face recognition, and financial risk prediction. Conformal Predictions for Reliable Machine Learning: Theory, Adaptations and Applications captures the basic theory of the framework, demonstrates how to apply it to real-world problems, and presents several adaptations, including active learning, change detection, and anomaly detecti
International Nuclear Information System (INIS)
Slipicevic, K.
1968-12-01
Following a review of the existing theories od resonance absorption this thesis includes a new approach for calculating the effective resonance integral of absorbed neutrons, new approximate formula for the penetration factor, an analysis of the effective resonance integral and the correction of the resonance integral taking into account the interference of potential and resonance dissipation. A separate chapter is devoted to calculation of the effective resonance integral for the regular reactor lattice with cylindrical fuel elements
Building a Middle-Range Theory of Adaptive Spirituality.
Dobratz, Marjorie C
2016-04-01
The purpose of this article is to describe a Roy adaptation model based- research abstraction, the findings of which were synthesized into a middle-range theory (MRT) of adaptive spirituality. The published literature yielded 21 empirical studies that investigated religion/spirituality. Quantitative results supported the influence of spirituality on quality of life, psychosocial adjustment, well-being, adaptive coping, and the self-concept mode. Qualitative findings showed the importance of spiritual expressions, values, and beliefs in adapting to chronic illness, bereavement, death, and other life transitions. These findings were abstracted into six theoretical statements, a conceptual definition of adaptive spirituality, and three hypotheses for future testing. © The Author(s) 2016.
Adaptive reconstructions for magnetic resonance imaging of moving organs
International Nuclear Information System (INIS)
Lohezic, Maelene
2011-01-01
Magnetic resonance imaging (MRI) is a valuable tool for the clinical diagnosis for brain imaging as well as cardiac and abdominal imaging. For instance, MRI is the only modality that enables the visualization and characterization myocardial edema. However, motion remains a challenging problem for cardiac MRI. Breathing as well as cardiac beating have to be carefully handled during patient examination. Moreover they limit the achievable temporal and spatial resolution of the images. In this work an approach that takes these physiological motions into account during image reconstruction process has been proposed. It allows performing cardiac examination while breathing freely. First, an iterative reconstruction algorithm, that compensates motion estimated from a motion model constrained by physiological signals, is applied to morphological cardiac imaging. A semi-automatic method for edema detection has been tested on reconstructed images. It has also been associated with an adaptive acquisition strategy which enables free-breathing end-systolic imaging. This reconstruction has then been extended to the assessment of transverse relaxation times T2, which is used for myocardial edema characterization. The proposed method, ARTEMIS, enables free-breathing T2 mapping without additional acquisition time. The proposed free breathing approaches take advantage of physiological signals to estimate the motion that occurs during MR acquisitions. Several solutions have been tested to measure this information. Among them, accelerometer-based external sensors allow local measurements at several locations. Another approach consists in the use of k-space based measurements, which are 'embedded' inside the MRI pulse sequence (navigator) and prevent from the requirement of additional recording hardware. Hence, several adaptive reconstruction algorithms were developed to obtain diagnostic information from free breathing acquisitions. These works allow performing efficient and
Contraction theory based adaptive synchronization of chaotic systems
International Nuclear Information System (INIS)
Sharma, B.B.; Kar, I.N.
2009-01-01
Contraction theory based stability analysis exploits the incremental behavior of trajectories of a system with respect to each other. Application of contraction theory provides an alternative way for stability analysis of nonlinear systems. This paper considers the design of a control law for synchronization of certain class of chaotic systems based on backstepping technique. The controller is selected so as to make the error dynamics between the two systems contracting. Synchronization problem with and without uncertainty in system parameters is discussed and necessary stability proofs are worked out using contraction theory. Suitable adaptation laws for unknown parameters are proposed based on the contraction principle. The numerical simulations verify the synchronization of the chaotic systems. Also parameter estimates converge to their true values with the proposed adaptation laws.
Resonant power converter comprising adaptive dead-time control
DEFF Research Database (Denmark)
2017-01-01
The invention relates in a first aspect to a resonant power converter comprising: a first power supply rail for receipt of a positive DC supply voltage and a second power supply rail for receipt of a negative DC supply voltage. The resonant power converter comprises a resonant network with an input...... terminal for receipt of a resonant input voltage from a driver circuit. The driver circuit is configured for alternatingly pulling the resonant input voltage towards the positive and negative DC supply voltages via first and second semiconductor switches, respectively, separated by intervening dead...
Eco-evolutionary feedbacks, adaptive dynamics and evolutionary rescue theory
Ferriere, Regis; Legendre, Stéphane
2013-01-01
Adaptive dynamics theory has been devised to account for feedbacks between ecological and evolutionary processes. Doing so opens new dimensions to and raises new challenges about evolutionary rescue. Adaptive dynamics theory predicts that successive trait substitutions driven by eco-evolutionary feedbacks can gradually erode population size or growth rate, thus potentially raising the extinction risk. Even a single trait substitution can suffice to degrade population viability drastically at once and cause ‘evolutionary suicide’. In a changing environment, a population may track a viable evolutionary attractor that leads to evolutionary suicide, a phenomenon called ‘evolutionary trapping’. Evolutionary trapping and suicide are commonly observed in adaptive dynamics models in which the smooth variation of traits causes catastrophic changes in ecological state. In the face of trapping and suicide, evolutionary rescue requires that the population overcome evolutionary threats generated by the adaptive process itself. Evolutionary repellors play an important role in determining how variation in environmental conditions correlates with the occurrence of evolutionary trapping and suicide, and what evolutionary pathways rescue may follow. In contrast with standard predictions of evolutionary rescue theory, low genetic variation may attenuate the threat of evolutionary suicide and small population sizes may facilitate escape from evolutionary traps. PMID:23209163
Eco-evolutionary feedbacks, adaptive dynamics and evolutionary rescue theory.
Ferriere, Regis; Legendre, Stéphane
2013-01-19
Adaptive dynamics theory has been devised to account for feedbacks between ecological and evolutionary processes. Doing so opens new dimensions to and raises new challenges about evolutionary rescue. Adaptive dynamics theory predicts that successive trait substitutions driven by eco-evolutionary feedbacks can gradually erode population size or growth rate, thus potentially raising the extinction risk. Even a single trait substitution can suffice to degrade population viability drastically at once and cause 'evolutionary suicide'. In a changing environment, a population may track a viable evolutionary attractor that leads to evolutionary suicide, a phenomenon called 'evolutionary trapping'. Evolutionary trapping and suicide are commonly observed in adaptive dynamics models in which the smooth variation of traits causes catastrophic changes in ecological state. In the face of trapping and suicide, evolutionary rescue requires that the population overcome evolutionary threats generated by the adaptive process itself. Evolutionary repellors play an important role in determining how variation in environmental conditions correlates with the occurrence of evolutionary trapping and suicide, and what evolutionary pathways rescue may follow. In contrast with standard predictions of evolutionary rescue theory, low genetic variation may attenuate the threat of evolutionary suicide and small population sizes may facilitate escape from evolutionary traps.
Directory of Open Access Journals (Sweden)
Shaofei Xie
2012-02-01
Full Text Available Based on the theory of stochastic resonance, an adaptive single-well stochastic resonance (ASSR coupled with genetic algorithm was developed to enhance the signal-to-noise ratio of weak chromatographic signals. In conventional stochastic resonance algorithm, there are two or more parameters needed to be optimized and the proper parameters values were obtained by a universal searching within a given range. In the developed ASSR, the optimization of system parameter was simplified and automatic implemented. The ASSR was applied to the trace analysis of clenbuterol in human urine and it helped to significantly improve the limit of detection and limit of quantification of clenbuterol. Good linearity, precision and accuracy of the proposed method ensure that it could be an effective tool for trace analysis and the improvement of detective sensibility of current detectors.
A general theory for bandgap estimation in locally resonant metastructures
Sugino, C.; Xia, Y.; Leadenham, S.; Ruzzene, M.; Erturk, A.
2017-10-01
Locally resonant metamaterials are characterized by bandgaps at wavelengths that are much larger than the lattice size, enabling low-frequency vibration attenuation. Typically, bandgap analyses and predictions rely on the assumption of traveling waves in an infinite medium, and do not take advantage of modal representations typically used for the analysis of the dynamic behavior of finite structures. Recently, we developed a method for understanding the locally resonant bandgap in uniform finite metamaterial beams using modal analysis. Here we extend that framework to general locally resonant 1D and 2D metastructures (i.e. locally resonant metamaterial-based finite structures) with specified boundary conditions using a general operator formulation. Using this approach, along with the assumption of an infinite number of resonators tuned to the same frequency, the frequency range of the locally resonant bandgap is easily derived in closed form. Furthermore, the bandgap expression is shown to be the same regardless of the type of vibration problem under consideration, depending only on the added mass ratio and target frequency. For practical designs with a finite number of resonators, it is shown that the number of resonators required for the bandgap to appear increases with increased target frequency, i.e. more resonators are required for higher vibration modes. Additionally, it is observed that there is an optimal, finite number of resonators which gives a bandgap that is wider than the infinite-resonator bandgap, and that the optimal number of resonators increases with target frequency and added mass ratio. As the number of resonators becomes sufficiently large, the bandgap converges to the derived infinite-resonator bandgap. Furthermore, the derived bandgap edge frequencies are shown to agree with results from dispersion analysis using the plane wave expansion method. The model is validated experimentally for a locally resonant cantilever beam under base
Augmentation of Sensorimotor Adaptability Using Stochastic Resonance Technologies
National Aeronautics and Space Administration — Astronauts experience sensorimotor dysfunction during adaption to g-transitions that occur when entering and exiting microgravity. These sensorimotor disturbances...
Darwinian adaptation, population genetics and the streetcar theory of evolution.
Hammerstein, P
1996-01-01
This paper investigates the problem of how to conceive a robust theory of phenotypic adaptation in non-trivial models of evolutionary biology. A particular effort is made to develop a foundation of this theory in the context of n-locus population genetics. Therefore, the evolution of phenotypic traits is considered that are coded for by more than one gene. The potential for epistatic gene interactions is not a priori excluded. Furthermore, emphasis is laid on the intricacies of frequency-dependent selection. It is first discussed how strongly the scope for phenotypic adaptation is restricted by the complex nature of 'reproduction mechanics' in sexually reproducing diploid populations. This discussion shows that one can easily lose the traces of Darwinism in n-locus models of population genetics. In order to retrieve these traces, the outline of a new theory is given that I call 'streetcar theory of evolution'. This theory is based on the same models that geneticists have used in order to demonstrate substantial problems with the 'adaptationist programme'. However, these models are now analyzed differently by including thoughts about the evolutionary removal of genetic constraints. This requires consideration of a sufficiently wide range of potential mutant alleles and careful examination of what to consider as a stable state of the evolutionary process. A particular notion of stability is introduced in order to describe population states that are phenotypically stable against the effects of all mutant alleles that are to be expected in the long-run. Surprisingly, a long-term stable state can be characterized at the phenotypic level as a fitness maximum, a Nash equilibrium or an ESS. The paper presents these mathematical results and discusses - at unusual length for a mathematical journal - their fundamental role in our current understanding of evolution.
Local resonance bandgaps in periodic media: theory and experiment.
Raghavan, L; Phani, A Srikantha
2013-09-01
Periodic composites such as acoustic metamaterials use local resonance phenomenon in designing low frequency sub-Bragg bandgaps. These bandgaps emerge from a resonant scattering interaction between a propagating wave and periodically arranged resonators. This paper develops a receptance coupling technique to combine the dynamics of the resonator with the unit cell dynamics of the background medium to analyze flexural wave transmission in a periodic structure, involving a single degree of freedom coupling between the medium and the resonator. Receptance techniques allow for a straightforward extension to higher dimensional systems with multiple degrees of freedom coupling and for easier experimental measurements. Closed-form expressions for the location and width of sub-Bragg bandgaps are obtained. Rigid body modes of the unit cell of the background medium are shown to set the bounding frequencies for local resonance bandgaps. Results from the receptance analysis compare well with Bloch wave analysis and experiments performed on a finite structural beam with periodic masses and resonators. Stronger coupling and inertia of the resonator increase the local resonance bandgap width. Two-fold periodicity widens the Bragg bandgap, narrowed by local resonators, thus expanding the design space and highlighting the advantages of hierarchical periodicity.
Rabi resonance in spin systems: theory and experiment.
Layton, Kelvin J; Tahayori, Bahman; Mareels, Iven M Y; Farrell, Peter M; Johnston, Leigh A
2014-05-01
The response of a magnetic resonance spin system is predicted and experimentally verified for the particular case of a continuous wave amplitude modulated radiofrequency excitation. The experimental results demonstrate phenomena not previously observed in magnetic resonance systems, including a secondary resonance condition when the amplitude of the excitation equals the modulation frequency. This secondary resonance produces a relatively large steady state magnetisation with Fourier components at harmonics of the modulation frequency. Experiments are in excellent agreement with the theoretical prediction derived from the Bloch equations, which provides a sound theoretical framework for future developments in NMR spectroscopy and imaging. Copyright © 2014 Elsevier Inc. All rights reserved.
The epigenetic side of human adaptation: hypotheses, evidences and theories.
Giuliani, Cristina; Bacalini, Maria Giulia; Sazzini, Marco; Pirazzini, Chiara; Franceschi, Claudio; Garagnani, Paolo; Luiselli, Donata
2015-01-01
Epigenetics represents a still unexplored research field in the understanding of micro- and macro-evolutionary mechanisms, as epigenetic changes create phenotypic diversity within both individuals and populations. The purpose of this review is to dissect the landscape of studies focused on DNA methylation, one of the most described epigenetic mechanisms, emphasizing the aspects that could be relevant in human adaptations. Theories and results here considered were collected from the most recent papers published. The matter of DNA methylation inheritance is here described as well as the recent evolutionary theories regarding the role of DNA methylation-and epigenetics in a broader sense-in human evolution. The complex relation between (1) DNA methylation and genetic variability and (2) DNA methylation and the environmental stimuli crucial in shaping genetic and phenotypic variability through the human lineage-such as diet, climate and pathogens exposure-are described. Papers about population epigenetics are also illustrated due to their high relevance in this context. Genetic, epigenetic and phenotypic variations of the species, together with cultural ones, are considerably shaped by a vast range of environmental stimuli, thus representing the foundation of all human bio-cultural adaptations.
Theory of electrically controlled resonant tunneling spin devices
Ting, David Z. -Y.; Cartoixa, Xavier
2004-01-01
We report device concepts that exploit spin-orbit coupling for creating spin polarized current sources using nonmagnetic semiconductor resonant tunneling heterostructures, without external magnetic fields. The resonant interband tunneling psin filter exploits large valence band spin-orbit interaction to provide strong spin selectivity.
Resonance Micro-Weighing of Sub-Picogram Mass with the Use of Adaptive Interferometer
Directory of Open Access Journals (Sweden)
Romashko Roman
2014-06-01
Full Text Available Mass of macroscopic object is easily measured by a suitable balance. However, this approach becomes inapplicable if mass of microscopic object is to be determined. Alternative approach for mass measurement is based on using the micromechanical resonator as an inertial balance where oscillation frequency is shifted by small quantities of adsorbed mass. In this work we present experimental results of applying an adaptive interferometry technique based on dynamic hologram recorded in photorefractive CdTe crystal for measuring picogram mass adsorbed on micromechanical resonators with dimensions 215×40×15 μm3. It is also shown that the resonance micro-weighing system based on adaptive interferometer has potential for reducing the threshold of mass detection down to 10-17 g in the case of using a resonator with sub-micron dimensions
Reaction theory for analysis of nuclear giant resonances production and decay processes
International Nuclear Information System (INIS)
Foglia, G.A.
1991-01-01
The existence of mixing parameters connected to the different decay forms of the giant resonances was theoretically justified, and their energy dependence determined as well using a reaction theory which treats in a consistent manner the giant multipolar resonances formation and their different decay modes. (L.C.J.A.)
Fault Diagnosis of Rotating Machinery Based on Adaptive Stochastic Resonance and AMD-EEMD
Directory of Open Access Journals (Sweden)
Peiming Shi
2016-01-01
Full Text Available An adaptive stochastic resonance and analytical mode decomposition-ensemble empirical mode decomposition (AMD-EEMD method is proposed for fault diagnosis of rotating machinery in this paper. Firstly, the stochastic resonance system is optimized by particle swarm optimization (PSO, and the best structure parameters are obtained. Then, the signal with noise is put into the stochastic resonance system and denoising and enhancing the signal. Secondly, the signal output from the stochastic resonance system is extracted by analytical mode decomposition (AMD method. Finally, the signal is decomposed by ensemble empirical mode decomposition (EEMD method. The simulation results show that the optimal stochastic resonance system can effectively improve the signal-to-noise ratio, and the number of effective components of EEMD decomposition is significantly reduced after using AMD, thus improving the decomposition results of EEMD and enhancing the amplitude of components frequency. Through the extraction of the rolling bearing fault signal feature proved that the method has a good effect.
Complex adaptive systems and game theory: An unlikely union
Hadzikadic, M.; Carmichael, T.; Curtin, C.
2010-01-01
A Complex Adaptive System is a collection of autonomous, heterogeneous agents, whose behavior is defined with a limited number of rules. A Game Theory is a mathematical construct that assumes a small number of rational players who have a limited number of actions or strategies available to them. The CAS method has the potential to alleviate some of the shortcomings of GT. On the other hand, CAS researchers are always looking for a realistic way to define interactions among agents. GT offers an attractive option for defining the rules of such interactions in a way that is both potentially consistent with observed real-world behavior and subject to mathematical interpretation. This article reports on the results of an effort to build a CAS system that utilizes GT for determining the actions of individual agents. ?? 2009 Wiley Periodicals, Inc. Complexity, 16,24-42, 2010.
Adaptive Leadership Theories Applied to the North Atlantic Treaty Organization (NATO)
2011-03-07
Adaptive Leadership Theories Applied to the North Atlantic Treaty Organization (NATO) By Major Christopher J. Wehri Essay...DATE 07 MAR 2011 2. REPORT TYPE 3. DATES COVERED 00-00-2011 to 00-00-2011 4. TITLE AND SUBTITLE Adaptive Leadership Theories Applied to the...the culturally diverse European environment. To solve its organizational problems NATO must consider various adaptive leadership theories and
Modeling Nonlinear Acoustic Standing Waves in Resonators: Theory and Experiments
Raman, Ganesh; Li, Xiaofan; Finkbeiner, Joshua
2004-01-01
The overall goal of the cooperative research with NASA Glenn is to fundamentally understand, computationally model, and experimentally validate non-linear acoustic waves in enclosures with the ultimate goal of developing a non-contact acoustic seal. The longer term goal is to transition the Glenn acoustic seal innovation to a prototype sealing device. Lucas and coworkers are credited with pioneering work in Resonant Macrosonic Synthesis (RMS). Several Patents and publications have successfully illustrated the concept of Resonant Macrosonic Synthesis. To utilize this concept in practical application one needs to have an understanding of the details of the phenomenon and a predictive tool that can examine the waveforms produced within resonators of complex shapes. With appropriately shaped resonators one can produce un-shocked waveforms of high amplitude that would result in very high pressures in certain regions. Our goal is to control the waveforms and exploit the high pressures to produce an acoustic seal. Note that shock formation critically limits peak-to-peak pressure amplitudes and also causes excessive energy dissipation. Proper shaping of the resonator is thus critical to the use of this innovation.
Computerized Adaptive Test (CAT) Applications and Item Response Theory Models for Polytomous Items
Aybek, Eren Can; Demirtasli, R. Nukhet
2017-01-01
This article aims to provide a theoretical framework for computerized adaptive tests (CAT) and item response theory models for polytomous items. Besides that, it aims to introduce the simulation and live CAT software to the related researchers. Computerized adaptive test algorithm, assumptions of item response theory models, nominal response…
Double giant resonances in time-dependent relativistic mean-field theory
International Nuclear Information System (INIS)
Ring, P.; Podobnik, B.
1996-01-01
Collective vibrations in spherical nuclei are described in the framework of time-dependent relativistic mean-field theory (RMFT). Isoscalar quadrupole and isovector dipole oscillations that correspond to giant resonances are studied, and possible excitations of higher modes are investigated. We find evidence for modes which can be interpreted as double resonances. In a quantized RMFT they correspond to two-phonon states. (orig.)
Neutron Resonance Theory for Nuclear Reactor Applications: Modern Theory and Practices.
Energy Technology Data Exchange (ETDEWEB)
Hwang, Richard N. [Argonne National Lab. (ANL), Argonne, IL (United States); Blomquist, Roger N. [Argonne National Lab. (ANL), Argonne, IL (United States); Leal, Luiz C. [Inst. de Radioprotection et de SÃ»rete Nucleaire (ISRN), Fontenay-aux-Roses (France); Yang, Won Sik [Purdue Univ., West Lafayette, IN (United States)
2016-09-24
The neutron resonance phenomena constitute one of the most fundamental subjects in nuclear physics as well as in reactor physics. It is the area where the concepts of nuclear interaction and the treatment of the neutronic balance in reactor fuel lattices become intertwined. The latter requires the detailed knowledge of resonance structures of many nuclides of practical interest to the development of nuclear energy. The most essential element in reactor physics is to provide an accurate account of the intricate balance between the neutrons produced by the fission process and neutrons lost due to the absorption process as well as those leaking out of the reactor system. The presence of resonance structures in many major nuclides obviously plays an important role in such processes. There has been a great deal of theoretical and practical interest in resonance reactions since Fermi’s discovery of resonance absorption of neutrons as they were slowed down in water. The resonance absorption became the center of attention when the question was raised as to the feasibility of the self-sustaining chain reaction in a natural uranium-fueled system. The threshold of the nuclear era was crossed almost eighty years ago when Fermi and Szilard observed that a substantial reduction in resonance absorption is possible if the uranium was made into the form of lumps instead of a homogeneous mixture with water. In the West, the first practical method for estimating the resonance escape probability in a reactor cell was pioneered by Wigner et al in early forties.
Kuhn, John R., Jr.
2009-01-01
Drawing upon the theories of complexity and complex adaptive systems and the Singerian Inquiring System from C. West Churchman's seminal work "The Design of Inquiring Systems" the dissertation herein develops a systems design theory for continuous auditing systems. The dissertation consists of discussion of the two foundational theories,…
Theory, Instrumentation and Applications of Magnetoelastic Resonance Sensors: A Review
Grimes, Craig A.; Roy, Somnath C.; Rani, Sanju; Cai, Qingyun
2011-01-01
Thick-film magnetoelastic sensors vibrate mechanically in response to a time varying magnetic excitation field. The mechanical vibrations of the magnetostrictive magnetoelastic material launch, in turn, a magnetic field by which the sensor can be monitored. Magnetic field telemetry enables contact-less, remote-query operation that has enabled many practical uses of the sensor platform. This paper builds upon a review paper we published in Sensors in 2002 (Grimes, C.A.; et al. Sensors 2002, 2, 294–313), presenting a comprehensive review on the theory, operating principles, instrumentation and key applications of magnetoelastic sensing technology. PMID:22163768
Theory, Instrumentation and Applications of Magnetoelastic Resonance Sensors: A Review
Directory of Open Access Journals (Sweden)
Craig A. Grimes
2011-03-01
Full Text Available Thick-film magnetoelastic sensors vibrate mechanically in response to a time varying magnetic excitation field. The mechanical vibrations of the magnetostrictive magnetoelastic material launch, in turn, a magnetic field by which the sensor can be monitored. Magnetic field telemetry enables contact-less, remote-query operation that has enabled many practical uses of the sensor platform. This paper builds upon a review paper we published in Sensors in 2002 (Grimes, C.A.; et al. Sensors 2002, 2, 294-313, presenting a comprehensive review on the theory, operating principles, instrumentation and key applications of magnetoelastic sensing technology.
An application of adaption-innovation theory to bioremediation
Energy Technology Data Exchange (ETDEWEB)
Guerin, L.J. [World Trade Centre, Melbourne, Victoria (Australia); Guerin, T.F. [Minenco Bioremediation Services, Bundoora, Victoria (Australia)
1995-12-31
This paper provides a discussion of the potential application of the Kirton Adaption-Innovation Inventory (KAI) for assessing the adaptive-innovative cognitive style of individuals and organizations within the bioremediation industry. Human-resource and line managers, or other individuals responsible for staff evaluation, selection, and project planning, should consider using the KAI to assist them in selecting individuals for specific roles requiring either an innovative or adaptive style. The KAI, a measure for assessing adaption-innovation at the individual employee level, is introduced and its potential value in the bioremediation industry is discussed.
Feasibility of energy harvesting from a rotating tire based on the theory of stochastic resonance
International Nuclear Information System (INIS)
Zhang, Y; Zheng, R; Nakano, K
2014-01-01
Recently the use of nonlinear bi-stable micro-electro mechanical systems (MEMS) to achieve automobile tire vibration power generation has made some progress. However, the theory of stochastic resonance has not been successfully applied to automobile tires, which can produce a larger vibrational response than for a typical resonance while inputting a weak periodic force and noise excitation into a nonlinear bi-stable system. Hence, in this paper, in view of the principle of stochastic resonance, a new model is derived by positioning a magnetic end mass attached to a cantilever beam and another permanent magnet with the same polarity on the frame. Due to the road noise excitation along with the periodic force inputted to the mechanism, whether the phenomenon of stochastic resonance can happen will be discussed. Meanwhile, on the basis of Kramers rate and duffing equations the preliminary experimental device is also designed
Peli, Gabor
Organizational populations can alter via the individual adaptation of incumbent organizations or via new entrants that match actual conditions. The Red Queen and inertia theories of organizational ecology represent these two forms of population adjustment. However, some of their conclusions
Kretschmann-Raether configuration: Revision of the theory of resonant interaction
Akimov, Yuriy; Pam, Mei Er; Sun, Song
2017-10-01
In classical Kretschmann-Raether configuration, the minimum appearing in reflectance is conventionally attributed to the resonance on a surface plasmon polariton of the metal/dielectric interface. The hypothesis about resonance on the subsystem plasmon polariton arises from the theory of eigenwave coupling in two adjoining domains. In this contribution, the theory of coupled eigenwaves is revised and tested for accuracy. It is revealed to have quite strong inherent limitations for thin metal films. This fact puts the hypothesis about coupling of a laser beam to the surface plasmon polariton in Kretschmann-Raether configuration in doubt. The doubt is further confirmed with the analysis of reflectance performed for the resonant eigenwave number. It demonstrates that the incident light resonates not on the subsystem surface plasmon polariton, but on the incoming polariton of the whole system. Detailed consideration of the system eigenwaves reveals three distinct regimes of Kretschmann-Raether configuration, where the incident light resonates on different types of incoming plasmon polaritons. Among them, the regime of coupling to transmission unguided plasmon polaritons provides the most powerful interaction with up to 100% efficiency.
Applications of decision theory to computer-based adaptive instructional systems
Vos, Hendrik J.
1988-01-01
This paper considers applications of decision theory to the problem of instructional decision-making in computer-based adaptive instructional systems, using the Minnesota Adaptive Instructional System (MAIS) as an example. The first section indicates how the problem of selecting the appropriate amount of instruction in MAIS can be situated within the general framework of empirical Bayesian decision theory. The linear loss model and the classical test model are discussed in this context. The s...
Adapting Structuration Theory as a Comprehensive Theory for Distance Education: The ASTIDE Model
Aktaruzzaman, Md; Plunkett, Margaret
2016-01-01
Distance Education (DE) theorists have argued about the requirement for a theory to be comprehensive in a way that can explicate many of the activities associated with DE. Currently, Transactional Distance Theory (TDT) (Moore, 1993) and the Theory of Instructional Dialogue (IDT) (Caspi & Gorsky, 2006) are the most prominent theories, yet they…
Brief Report: Translation and Adaptation of the Theory of Mind Inventory to Spanish
Pujals, Elena; Batlle, Santiago; Camprodon, Ester; Pujals, Sílvia; Estrada, Xavier; Aceña, Marta; Petrizan, Araitz; Duñó, Lurdes; Martí, Josep; Martin, Luis Miguel; Pérez-Solá, Víctor
2016-01-01
The Theory of Mind Inventory is an informant measure designed to evaluate children's theory of mind competence. We describe the translation and cultural adaptation of the inventory by the following process: (1) translation from English to Spanish by two independent certified translators; (2) production of an agreed version by a multidisciplinary…
Nonlinear theory of wakefield excitation in a rectangular multizone dielectric resonator
Directory of Open Access Journals (Sweden)
K. V. Galaydych
2011-01-01
Full Text Available A nonlinear self-consistent theory has been constructed and used to investigate numerically the wakefield excitation in multilayered dielectric resonators by relativistic electron bunches. Analytical expressions for solenoidal and potential components of an excited electromagnetic field have been derived. The excitation of a five-zone dielectric resonator by relativistic electron bunches was numerically investigated and comparison was made between the longitudinal distribution of an axial electric field and the results obtained previously for a corresponding problem in the waveguide formulation. The necessity of optimizing geometrical parameters of the resonator to reduce mode amplitudes nonresonant with a bunch, and to obtain a symmetric distribution of the longitudinal electric field component in the drive and accelerating channels, has been demonstrated.
International Nuclear Information System (INIS)
Bouland, O.
2005-01-01
The paper reviews some current approximations used in R-matrix theory for calculating angular integrated nuclear cross sections. In particular, it distinguishes the SLBW and MLBW approximations of their practical applications ENDF-oriented. This paper also focuses on the problem of prior resonance parameter determination compulsory for any experimental data adjustment in the resolved resonance range. The major contribution of this paper concerns R-matrix calculations made with no approximations using the SAMMY program which is developed at the Oak Ridge National Laboratory. These new R-matrix calculations are applied to real cases which experimental data are extracted from radiative capture gamma rays measurements on 23 Na, 19 F and 238 U isotopes. Small but significant R-matrix effects show up in the wings of the resonances and especially at thermal energies when calculating the capture cross section without the classic Reich-Moore approximation. (author)
Theory of time-dependent intense-field collisional resonance fluorescence
Kleiber, P. D.; Cooper, J.; Burnett, K.; Kunasz, C. V.; Raymer, M. G.
1983-01-01
The time-dependent theory of Courtens and Szoke (1977) is generalized using the approach of Burnett et al. (1982) to derive time-dependent spectral intensities of resonance fluorescence from atoms driven by a pulsed laser in the presence of collisions. These results are valid both for laser detunings inside and outside the usual impact region of the spectrum, including Zeeman degeneracy effects. This theory is applied to a simple but important example (J = 0 to J = 1) to obtain quantitative predictions for the observable scattered-light spectrum which can be directly compared with recent experiments.
Resonance Effective Theory Approach to τ → 3πντ Decays
International Nuclear Information System (INIS)
Gomez Dumm, D.; Pich, A.; Portoles, J.
2004-01-01
The decays τ → 3πντ are analyzed in the framework of the resonance effective theory of QCD, We derive the effective chiral Lagrangian relevant for the evaluation of the hadronic axial-vector current, taking into account the constraints imposed by QCD on the high energy asymptotic behaviour. Then we fit the unknown parameters to the spectral function and branching ratio measured by ALEPH, showing that the theory is in good agreement with experimental data. A detailed description of the work sketched here can be found
Adaptive Core Simulation Employing Discrete Inverse Theory - Part II: Numerical Experiments
International Nuclear Information System (INIS)
Abdel-Khalik, Hany S.; Turinsky, Paul J.
2005-01-01
Use of adaptive simulation is intended to improve the fidelity and robustness of important core attribute predictions such as core power distribution, thermal margins, and core reactivity. Adaptive simulation utilizes a selected set of past and current reactor measurements of reactor observables, i.e., in-core instrumentation readings, to adapt the simulation in a meaningful way. The companion paper, ''Adaptive Core Simulation Employing Discrete Inverse Theory - Part I: Theory,'' describes in detail the theoretical background of the proposed adaptive techniques. This paper, Part II, demonstrates several computational experiments conducted to assess the fidelity and robustness of the proposed techniques. The intent is to check the ability of the adapted core simulator model to predict future core observables that are not included in the adaption or core observables that are recorded at core conditions that differ from those at which adaption is completed. Also, this paper demonstrates successful utilization of an efficient sensitivity analysis approach to calculate the sensitivity information required to perform the adaption for millions of input core parameters. Finally, this paper illustrates a useful application for adaptive simulation - reducing the inconsistencies between two different core simulator code systems, where the multitudes of input data to one code are adjusted to enhance the agreement between both codes for important core attributes, i.e., core reactivity and power distribution. Also demonstrated is the robustness of such an application
Block-structured Adaptive Mesh Refinement - Theory, Implementation and Application
Directory of Open Access Journals (Sweden)
Deiterding Ralf
2011-12-01
Full Text Available Structured adaptive mesh refinement (SAMR techniques can enable cutting-edge simulations of problems governed by conservation laws. Focusing on the strictly hyperbolic case, these notes explain all algorithmic and mathematical details of a technically relevant implementation tailored for distributed memory computers. An overview of the background of commonly used finite volume discretizations for gas dynamics is included and typical benchmarks to quantify accuracy and performance of the dynamically adaptive code are discussed. Large-scale simulations of shock-induced realistic combustion in non-Cartesian geometry and shock-driven fluid-structure interaction with fully coupled dynamic boundary motion demonstrate the applicability of the discussed techniques for complex scenarios.
Online Magnetic Resonance Image Guided Adaptive Radiation Therapy: First Clinical Applications
International Nuclear Information System (INIS)
Acharya, Sahaja; Fischer-Valuck, Benjamin W.; Kashani, Rojano; Parikh, Parag; Yang, Deshan; Zhao, Tianyu; Green, Olga; Wooten, Omar; Li, H. Harold; Hu, Yanle; Rodriguez, Vivian; Olsen, Lindsey; Robinson, Clifford; Michalski, Jeff; Mutic, Sasa; Olsen, Jeffrey
2016-01-01
Purpose: To demonstrate the feasibility of online adaptive magnetic resonance (MR) image guided radiation therapy (MR-IGRT) through reporting of our initial clinical experience and workflow considerations. Methods and Materials: The first clinically deployed online adaptive MR-IGRT system consisted of a split 0.35T MR scanner straddling a ring gantry with 3 multileaf collimator-equipped 60 Co heads. The unit is supported by a Monte Carlo–based treatment planning system that allows real-time adaptive planning with the patient on the table. All patients undergo computed tomography and MR imaging (MRI) simulation for initial treatment planning. A volumetric MRI scan is acquired for each patient at the daily treatment setup. Deformable registration is performed using the planning computed tomography data set, which allows for the transfer of the initial contours and the electron density map to the daily MRI scan. The deformed electron density map is then used to recalculate the original plan on the daily MRI scan for physician evaluation. Recontouring and plan reoptimization are performed when required, and patient-specific quality assurance (QA) is performed using an independent in-house software system. Results: The first online adaptive MR-IGRT treatments consisted of 5 patients with abdominopelvic malignancies. The clinical setting included neoadjuvant colorectal (n=3), unresectable gastric (n=1), and unresectable pheochromocytoma (n=1). Recontouring and reoptimization were deemed necessary for 3 of 5 patients, and the initial plan was deemed sufficient for 2 of the 5 patients. The reasons for plan adaptation included tumor progression or regression and a change in small bowel anatomy. In a subsequently expanded cohort of 170 fractions (20 patients), 52 fractions (30.6%) were reoptimized online, and 92 fractions (54.1%) were treated with an online-adapted or previously adapted plan. The median time for recontouring, reoptimization, and QA was 26
Li, Xiaopeng; Chen, Yangyang; Hu, Gengkai; Huang, Guoliang
2018-04-01
Designing lightweight materials and/or structures for broadband low-frequency noise/vibration mitigation is an issue of fundamental importance both practically and theoretically. In this paper, by leveraging the concept of frequency-dependent effective stiffness control, we numerically and experimentally demonstrate, for the first time, a self-adaptive metamaterial beam with digital circuit controlled mechanical resonators for strong and broadband flexural wave attenuation at subwavelength scales. The digital controllers that are capable of feedback control of piezoelectric shunts are integrated into mechanical resonators in the metamaterial, and the transfer function is semi-analytically determined to realize an effective bending stiffness in a quadratic function of the wave frequency for adaptive band gaps. The digital as well as analog control circuits as the backbone of the system are experimentally realized with the guarantee stability of the whole electromechanical system in whole frequency regions, which is the most challenging problem so far. Our experimental results are in good agreement with numerical predictions and demonstrate the strong wave attenuation in almost a three times larger frequency region over the bandwidth of a passive metamaterial. The proposed metamaterial could be applied in a range of applications in the design of elastic wave control devices.
Energy Technology Data Exchange (ETDEWEB)
Yao, De-Liang [Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics,Forschungszentrum Jülich, D-52425 Jülich (Germany); Siemens, D. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Bernard, V. [Groupe de Physique Théorique, Institut de Physique Nucléaire, UMR 8606,CNRS, University Paris-Sud, Université Paris-Saclay, 91405 Orsay Cedex (France); Epelbaum, E. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Gasparyan, A.M. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); SSC RF ITEP, Bolshaya Cheremushkinskaya 25, 117218 Moscow (Russian Federation); Gegelia, J. [Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics,Forschungszentrum Jülich, D-52425 Jülich (Germany); Tbilisi State University, 0186 Tbilisi (Georgia); Krebs, H. [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Meißner, Ulf-G. [Helmholtz Institut für Strahlen- und Kernphysik andBethe Center for Theoretical Physics, Universität Bonn, D-53115 Bonn (Germany); Institute for Advanced Simulation, Institut für Kernphysik and Jülich Center for Hadron Physics,Forschungszentrum Jülich, D-52425 Jülich (Germany)
2016-05-05
We present the results of a third order calculation of the pion-nucleon scattering amplitude in a chiral effective field theory with pions, nucleons and delta resonances as explicit degrees of freedom. We work in a manifestly Lorentz invariant formulation of baryon chiral perturbation theory using dimensional regularization and the extended on-mass-shell renormalization scheme. In the delta resonance sector, the on mass-shell renormalization is realized as a complex-mass scheme. By fitting the low-energy constants of the effective Lagrangian to the S- and P-partial waves a satisfactory description of the phase shifts from the analysis of the Roy-Steiner equations is obtained. We predict the phase shifts for the D and F waves and compare them with the results of the analysis of the George Washington University group. The threshold parameters are calculated both in the delta-less and delta-full cases. Based on the determined low-energy constants, we discuss the pion-nucleon sigma term. Additionally, in order to determine the strangeness content of the nucleon, we calculate the octet baryon masses in the presence of decuplet resonances up to next-to-next-to-leading order in SU(3) baryon chiral perturbation theory. The octet baryon sigma terms are predicted as a byproduct of this calculation.
Li, Nian; Wang, Bin; Qian, Zhenghua
2018-03-26
Mindlin's two-dimensional theory has been derived and applied to research on quartz resonators for a long time. However, most works have focused on vibrations varying only in two directions, including thickness direction, while the effect of other directions like the length or width direction is normally neglected. Besides, researchers often model quartz resonators as fully electroded plates because of the resulting simplicity. Since a real device is finite in all directions and is only centrally electroded, results obtained in such works cannot offer quantitative information on vibrations with enough accuracy. In this paper, a theoretical analysis of a rectangular trapped-energy resonator of AT-cut quartz is studied using the Ritz method, associated with the variational formulation of Mindlin's first-order equations. Frequency spectra and mode shapes of a real-scaled trapped-energy resonator, which is finite in all directions, are obtained with the consideration of mode couplings among thickness-shear mode, thickness-twist mode, and flexural mode. Results show the existence of an energy-trapping and coupling phenomenon and are helpful for thorough and accurate understanding of quartz resonator vibrations. Detailed discussions on the effects of structural parameters on mode couplings and energy trapping are provided, and the results can helpfully guide the selection of aspect ratio, length/thickness ratio, and electrode inertia in device design.
A generalization of the Livolant-Jeanpierre theory for resonance absorption calculation
International Nuclear Information System (INIS)
Reuss, P.
1985-04-01
Because of the large number of heavy nuclide resonances a detailed neutron flux calculation in the epithermal range cannot be made by standard nuclear reactor codes: it would need several tens of thousand of energy points. However, by using pre-calculated effective reaction rates only a few tens of groups are sufficient for accurate spectrum and reaction rate calculations, if a consistent formalism is used. Such a formalism was elaborated in the 1970s by M. Livolant and F. Jeanpierre (L.-J.) for the ''one resonant nuclide - one resonant zone'' problem, and was implemented in the APOLLO code. In practical cases there are several resonant nuclides and often resonant zones of different characteristics, e.g. a lattice constituted with different kinds of pins, a lattice with irregular ''water-holes'', a fuel element with temperature (therefore Doppler effect) gradients,... Since these problem cannot be correctly treated by APOLLO, a generalization of the formalism was derived. The basic principles were retained, and our aim was to construct an algorithm which would not require too expensive calculations. After a brief recall of the L.-J. theory, equations for the most general case are presented, some approximations for practical calculations proposed, and numerical tests on significant examples commented
“Theory of Food” as a Neurocognitive Adaptation
Allen, John S.
2012-01-01
Human adult cognition emerges over the course of development via the interaction of multiple critical neurocognitive networks. These networks evolved in response to various selection pressures, many of which were modified or intensified by the intellectual, technological, and socio-cultural environments that arose in connection with the evolution of genus Homo. Networks related to language and theory of mind clearly play an important role in adult cognition. Given the critical importance of f...
A quantitative evolutionary theory of adaptive behavior dynamics.
McDowell, J J
2013-10-01
The idea that behavior is selected by its consequences in a process analogous to organic evolution has been discussed for over 100 years. A recently proposed theory instantiates this idea by means of a genetic algorithm that operates on a population of potential behaviors. Behaviors in the population are represented by numbers in decimal integer (phenotypic) and binary bit string (genotypic) forms. One behavior from the population is emitted at random each time tick, after which a new population of potential behaviors is constructed by recombining parent behavior bit strings. If the emitted behavior produced a benefit to the organism, then parents are chosen on the basis of their phenotypic similarity to the emitted behavior; otherwise, they are chosen at random. After parent behavior recombination, the population is subjected to a small amount of mutation by flipping random bits in the population's bit strings. The behavior generated by this process of selection, reproduction, and mutation reaches equilibrium states that conform to every empirically valid equation of matching theory, exactly and without systematic error. These equations are known to describe the behavior of many vertebrate species, including humans, in a variety of experimental, naturalistic, natural, and social environments. The evolutionary theory also generates instantaneous dynamics and patterns of preference change in constantly changing environments that are consistent with the dynamics of live-organism behavior. These findings support the assertion that the world of behavior we observe and measure is generated by evolutionary dynamics. PsycINFO Database Record (c) 2013 APA, all rights reserved
THE BASIS OF RESONANCE-STRUCTURE THEORY FOR VIBROIMPACT UNLOADING OF THE VEHICLES
Directory of Open Access Journals (Sweden)
R. D. Iskovych-Lototskyi
2014-10-01
Full Text Available Purpose. The use of the main provisions of the resonance-structure theory for theoretical study of basic physical and mechanical processes taking place in unloading material during the vibrimpact discharge in order to substantiate the efficiency of their application. Methodology. Unloading material during vibroimpact unloading, as the study object, appeared as phenomenological model of spatial dispersion medium. The dynamics equations of unsteady forced particle oscillations of the "linked" structure under the action of vibration and impact loadings, taking into account the vibro rheological effect, with the establishment of resonance zones were considered. Findings. When considering the resonance zones of unstable forced oscillations of the "linked" structure particles it was found out that under the influence of vibration loadings the system is effectively affected by the monoharmonic pulse of external forces in the form of sinusoidal wave with an angular frequency. This frequency is equal to the main frequency of the natural oscillations of the unloading material. Under the impact loading it is necessary to affect the system by the accumulation of external force pulses in the form of single instant impulse. Under the given load conditions in these systems the phenomenon of resonance, which provides absolute deformation in handling system of the "linked" structure of the material due to discrete growth in the range of plastic deformations takes place. Absolute deformation, resulting in handling material exceed the permissible elastic deformations for the particles of this system and the destruction of the contact zones of these particles takes place. Originality. The authors studied unstable forced oscillations of the "linked" structure particles based on the phenomenological model of the spatial dispersion medium of unloading material. Thus, for each type of vibro-impact loads were calculated the conditions for resonant processes. That was
Kalman Filtered Bio Heat Transfer Model Based Self-adaptive Hybrid Magnetic Resonance Thermometry.
Zhang, Yuxin; Chen, Shuo; Deng, Kexin; Chen, Bingyao; Wei, Xing; Yang, Jiafei; Wang, Shi; Ying, Kui
2017-01-01
To develop a self-adaptive and fast thermometry method by combining the original hybrid magnetic resonance thermometry method and the bio heat transfer equation (BHTE) model. The proposed Kalman filtered Bio Heat Transfer Model Based Self-adaptive Hybrid Magnetic Resonance Thermometry, abbreviated as KalBHT hybrid method, introduced the BHTE model to synthesize a window on the regularization term of the hybrid algorithm, which leads to a self-adaptive regularization both spatially and temporally with change of temperature. Further, to decrease the sensitivity to accuracy of the BHTE model, Kalman filter is utilized to update the window at each iteration time. To investigate the effect of the proposed model, computer heating simulation, phantom microwave heating experiment and dynamic in-vivo model validation of liver and thoracic tumor were conducted in this study. The heating simulation indicates that the KalBHT hybrid algorithm achieves more accurate results without adjusting λ to a proper value in comparison to the hybrid algorithm. The results of the phantom heating experiment illustrate that the proposed model is able to follow temperature changes in the presence of motion and the temperature estimated also shows less noise in the background and surrounding the hot spot. The dynamic in-vivo model validation with heating simulation demonstrates that the proposed model has a higher convergence rate, more robustness to susceptibility problem surrounding the hot spot and more accuracy of temperature estimation. In the healthy liver experiment with heating simulation, the RMSE of the hot spot of the proposed model is reduced to about 50% compared to the RMSE of the original hybrid model and the convergence time becomes only about one fifth of the hybrid model. The proposed model is able to improve the accuracy of the original hybrid algorithm and accelerate the convergence rate of MR temperature estimation.
Theory of affine projection algorithms for adaptive filtering
Ozeki, Kazuhiko
2016-01-01
This book focuses on theoretical aspects of the affine projection algorithm (APA) for adaptive filtering. The APA is a natural generalization of the classical, normalized least-mean-squares (NLMS) algorithm. The book first explains how the APA evolved from the NLMS algorithm, where an affine projection view is emphasized. By looking at those adaptation algorithms from such a geometrical point of view, we can find many of the important properties of the APA, e.g., the improvement of the convergence rate over the NLMS algorithm especially for correlated input signals. After the birth of the APA in the mid-1980s, similar algorithms were put forward by other researchers independently from different perspectives. This book shows that they are variants of the APA, forming a family of APAs. Then it surveys research on the convergence behavior of the APA, where statistical analyses play important roles. It also reviews developments of techniques to reduce the computational complexity of the APA, which are important f...
Magnetic resonance image restoration via dictionary learning under spatially adaptive constraints.
Wang, Shanshan; Xia, Yong; Dong, Pei; Feng, David Dagan; Luo, Jianhua; Huang, Qiu
2013-01-01
This paper proposes a spatially adaptive constrained dictionary learning (SAC-DL) algorithm for Rician noise removal in magnitude magnetic resonance (MR) images. This algorithm explores both the strength of dictionary learning to preserve image structures and the robustness of local variance estimation to remove signal-dependent Rician noise. The magnitude image is first separated into a number of partly overlapping image patches. The statistics of each patch are collected and analyzed to obtain a local noise variance. To better adapt to Rician noise, a correction factor is formulated with the local signal-to-noise ratio (SNR). Finally, the trained dictionary is used to denoise each image patch under spatially adaptive constraints. The proposed algorithm has been compared to the popular nonlocal means (NLM) filtering and unbiased NLM (UNLM) algorithm on simulated T1-weighted, T2-weighted and PD-weighted MR images. Our results suggest that the SAC-DL algorithm preserves more image structures while effectively removing the noise than NLM and it is also superior to UNLM at low noise levels.
Sleep stabilizes visuomotor adaptation memory: a functional magnetic resonance imaging study.
Albouy, Genevieve; Vandewalle, Gilles; Sterpenich, Virginie; Rauchs, Geraldine; Desseilles, Martin; Balteau, Evelyne; Degueldre, Christian; Phillips, Christophe; Luxen, Andre; Maquet, Pierre
2013-04-01
The beneficial effect of sleep on motor memory consolidation is well known for motor sequence memory, but remains unsettled for visuomotor adaptation in humans. The aim of this study was to characterize more clearly the influence of sleep on consolidation of visuomotor adaptation using a between-subjects functional magnetic resonance imaging (fMRI) design contrasting sleep to total sleep deprivation. Our behavioural results, based on seven different parameters, show that sleep stabilizes performance whereas sleep deprivation deteriorates it. During training, while a set of cerebellar, striatal and cortical areas is activated in proportion to performance improvement, the recruitment of the hippocampus and frontal cortex protects motor memory against the detrimental effects of sleep deprivation. During retest after sleep loss a cerebello-cortical network, usually involved in the earliest stage of learning, was recruited to perform the task. In contrast, no changes in cerebral activity were observed after sleep, suggesting that it may only support the stabilization of the visuomotor adaptation memory trace. © 2012 European Sleep Research Society.
Wang, Jiao; Zhan, Tianrong; Huang, Gaoshan; Cui, Xugao; Hu, Xinhua; Mei, Yongfeng
2012-08-13
Tubular oxide optical microcavities with thin walls (Mie scattering theory. Novel material design and superior optical resonant properties in such self-rolled micro-tubular cavities promise many potential applications e.g. in optofluidic sensing and lasing.
Directory of Open Access Journals (Sweden)
Małgorzata Choczaj
2011-01-01
Full Text Available The basis of this deliberation is a critical discussion of common perspectives and research methodology concerning the notion of adaptation. The author searches for universal adaptation models, describes creating new techniques of translation and examines relations among arts. The aim of reminding and critical discussion of the state of research of adaptation is to find the threats referring to common acceptance of one research paradigm, i.e. the perspective of literary studies and semiotics. One of the effects of such a way of thinking may be ungrounded equating a book with a literary work as such, as well as perceiving a film as something second-rate, which often functions only in reference to a book. The author, who refers to Werner Faulstich’s concept of the media, sees the paradigm which is currently binding in the research of adaptation as incomplete and inconsistent. Thus, she is inclined to accept the point of view of media experts. According to that viewpoint, both the book and the film seem to be the media that process and transfer literature (a particular story, e.g. War of the Worlds in accordance with the principles of its own aesthetics. The concept encourages to change the scientific paradigm and liberates the notion of adaptation from all kinds of the consequences assumed by literary studies. It also allows to concentrate on the aesthetics of a particular medium.
Regeta, Khrystyna; Allan, Michael; Winstead, Carl; McKoy, Vincent; Mašín, Zdeněk; Gorfinkiel, Jimena D
2016-01-14
We measured differential cross sections for elastic (rotationally integrated) electron scattering on pyrimidine, both as a function of angle up to 180(∘) at electron energies of 1, 5, 10, and 20 eV and as a function of electron energy in the range 0.1-14 eV. The experimental results are compared to the results of the fixed-nuclei Schwinger variational and R-matrix theoretical methods, which reproduce satisfactorily the magnitudes and shapes of the experimental cross sections. The emphasis of the present work is on recording detailed excitation functions revealing resonances in the excitation process. Resonant structures are observed at 0.2, 0.7, and 4.35 eV and calculations for different symmetries confirm their assignment as the X̃(2)A2, Ã(2)B1, and B̃(2)B1 shape resonances. As a consequence of superposition of coherent resonant amplitudes with background scattering the B̃(2)B1 shape resonance appears as a peak, a dip, or a step function in the cross sections recorded as a function of energy at different scattering angles and this effect is satisfactorily reproduced by theory. The dip and peak contributions at different scattering angles partially compensate, making the resonance nearly invisible in the integral cross section. Vibrationally integrated cross sections were also measured at 1, 5, 10 and 20 eV and the question of whether the fixed-nuclei cross sections should be compared to vibrationally elastic or vibrationally integrated cross section is discussed.
Mitri, Farid
2014-11-01
The generalized theory of resonance scattering (GTRS) by an elastic spherical target in acoustics is extended to describe the arbitrary scattering of a finite beam using the addition theorem for the spherical wave functions of the first kind under a translation of the coordinate origin. The advantage of the proposed method over the standard discrete spherical harmonics transform previously used in the GTRS formalism is the computation of the off-axial beam-shape coefficients (BSCs) stemming from a closed-form partial-wave series expansion representing the axial BSCs in spherical coordinates. With this general method, the arbitrary acoustical scattering can be evaluated for any particle shape and size, whether the particle is partially or completely illuminated by the incident beam. Numerical examples for the axial and off-axial resonance scattering from an elastic sphere placed arbitrarily in the field of a finite circular piston transducer with uniform vibration are provided. Moreover, the 3-D resonance directivity patterns illustrate the theory and reveal some properties of the scattering. Numerous applications involving the scattering phenomenon in imaging, particle manipulation, and the characterization of multiphase flows can benefit from the present analysis because all physically realizable beams radiate acoustical waves from finite transducers as opposed to waves of infinite extent.
A Modified Adaptive Stochastic Resonance for Detecting Faint Signal in Sensors
Directory of Open Access Journals (Sweden)
Hengwei Li
2007-02-01
Full Text Available In this paper, an approach is presented to detect faint signals with strong noises in sensors by stochastic resonance (SR. We adopt the power spectrum as the evaluation tool of SR, which can be obtained by the fast Fourier transform (FFT. Furthermore, we introduce the adaptive filtering scheme to realize signal processing automatically. The key of the scheme is how to adjust the barrier height to satisfy the optimal condition of SR in the presence of any input. For the given input signal, we present an operable procedure to execute the adjustment scheme. An example utilizing one audio sensor to detect the fault information from the power supply is given. Simulation results show that th
International Nuclear Information System (INIS)
Sala, E.; Graves, M.J.; Abubacker, Z.; Kershaw, L.E.; Black, R.T.; Skinner, J.; Beavon, R.; Lomas, D.J.
2006-01-01
Aim: To evaluate the diagnostic performance of an interactive, adaptively averaged (AA) two-dimensional (2D) magnetic resonance cholangiography (MRC) technique in patients with suspected biliary disease by comparison to the standard MRC technique. Materials and methods: The AA 2D MRC method registers the images after acquisition, allowing summation of multiple images to improve the signal:noise ratio (SNR) and thereby potentially improve the visualization of bile ducts. One hundred and twenty-eight patients underwent both 2D conventional and AA magnetic resonance cholangiopancreatography (MRCP). Twenty-seven patients were excluded from the analysis as AA images could not be properly obtained due to technical failures. All examinations were performed using a 1.5 T whole-body MR system and a four-channel torso phased array coil. Images of 101 patients were adaptively averaged using an in-house developed program written in IDL. Two readers qualitatively evaluated the studies in consensus, blinded to acquisition details and without knowledge of clinical information. Results: The AA technique was significantly better than the conventional 2D MRC for the visualization of the second-order branch intrahepatic ducts (p < 00001). Overall, there was no significant difference in the diagnostic confidence between two techniques (p = 0.12). However, the AA technique showed a trend towards more confident diagnosis of biliary strictures (p = 0.055), likely due to better diagnostic confidence in identifying second order branch intrahepatic duct strictures (p = 0.054). Conclusion: Excluding those patients those patients in whom either satisfactory respiratory gating or a suitable kernel placement was not achieved, AA 2D MRC demonstrated a significant improvement in visualization of intrahepatic duct branches compared to standard MRC
τ→πππντ decays in the resonance effective theory
International Nuclear Information System (INIS)
Gomez Dumm, D.; Pich, A.; Portoles, J.
2004-01-01
τ→πππν τ decays are analyzed within the framework of the resonance effective theory of QCD. We work out the relevant Lagrangian that describes the axial-vector current hadronization contributing to these processes, in particular the local a 1 (1260)-ρ(770)-Goldstone interactions. The new coupling constants are constrained by imposing the asymptotic behavior of the corresponding spectral function within QCD. Hence we compare the theoretical framework with the experimental data, obtaining a good quality fit from the ALEPH spectral function and branching ratio. We also get values for the mass and on-shell width of the a 1 (1260) resonance. In this way we are able to provide the structure functions that have been measured by OPAL and CLEO-II and we find an excellent agreement
Flegr, Jaroslav
2013-01-16
Punctuational theories of evolution suggest that adaptive evolution proceeds mostly, or even entirely, in the distinct periods of existence of a particular species. The mechanisms of this punctuated nature of evolution suggested by the various theories differ. Therefore the predictions of particular theories concerning various evolutionary phenomena also differ.Punctuational theories can be subdivided into five classes, which differ in their mechanism and their evolutionary and ecological implications. For example, the transilience model of Templeton (class III), genetic revolution model of Mayr (class IV) or the frozen plasticity theory of Flegr (class V), suggests that adaptive evolution in sexual species is operative shortly after the emergence of a species by peripatric speciation--while it is evolutionary plastic. To a major degree, i.e. throughout 98-99% of their existence, sexual species are evolutionarily frozen (class III) or elastic (class IV and V) on a microevolutionary time scale and evolutionarily frozen on a macroevolutionary time scale and can only wait for extinction, or the highly improbable return of a population segment to the plastic state due to peripatric speciation.The punctuational theories have many evolutionary and ecological implications. Most of these predictions could be tested empirically, and should be analyzed in greater depth theoretically. The punctuational theories offer many new predictions that need to be tested, but also provide explanations for a much broader spectrum of known biological phenomena than classical gradualistic evolutionary theories.
Yu, Xudong; Long, Xingwu; Wei, Guo; Li, Geng; Qu, Tianliang
2015-04-01
A finite element model of the hemispherical resonator gyro (HRG) is established and the natural frequencies and vibration modes are investigated. The matrix perturbation technology in the random finite element method is first introduced to analyze the statistical characteristics of the natural frequencies of HRG. The influences of random material parameters and dimensional parameters on the natural frequencies are quantitatively described based on the probability theory. The statistics expressions of the random parameters are given and the influences of three key parameters on natural frequency are pointed out. These results are important for design and improvement of high accuracy HRG.
Theory of Electric-Field Effects on Electron-Spin-Resonance Hyperfine Couplings
International Nuclear Information System (INIS)
Karna, S.P.
1997-01-01
A quantum mechanical theory of the effects of a uniform electric field on electron-spin-resonance hyperfine couplings is presented. The electric-field effects are described in terms of perturbation coefficients which can be used to probe the local symmetry as well as the strength of the electric field at paramagnetic sites in a solid. Results are presented for the first-order perturbation coefficients describing the Bloembergen effect (linear electric-field effect on hyperfine coupling tensor) for the O atom and the OH radical. copyright 1997 The American Physical Society
Theory of resonant multiphoton ionization of krypton by intense ultraviolet laser radiation
International Nuclear Information System (INIS)
Tang, X.; Lambropoulos, P.; L'Huillier, A.; Dixit, S.N.
1989-01-01
We present a theoretical interpretation of the experimental results on three-photon-resonant four-photon ionization of Kr reported by Landen, Perry, and Campbell [Phys. Rev. Lett. 59, 2558 (1987)] and Perry and Landen [Phys. Rev. A 38, 2815 (1988)]. Our calculations are based on multichannel quantum-defect theory combined with a density-matrix formalism describing the spatiotemporal development of the process. We obtain good agreement with the data, which even at intensities as high as 10 14 W/cm 2 show the imprint of the underlying atomic structure
Resonant R-matrix theory of inelastic processes in collisions of electrons with HF molecules
International Nuclear Information System (INIS)
Fabrikant, I.I.; Kalin, S.A.; Kazansky, A.K.
1992-01-01
The resonant R-matrix theory is applied to the calculation of vibrational excitation and dissociative attachment cross sections in collisions of electrons with HF molecules. The parameters of our model were chosen by fitting our eigenphase sums for e-HF scattering to the results of ab initio R-matrix calculations by previous authors. Another set of parameters was chosen to get a better agreement with experimental results on vibrational excitation. Dissociative attachment cross sections calculated with these parameters are in good agreement with experimental results. We also calculated cross sections for vibrational excitation from excited states and angular distribution of the scattered electrons. (author)
Kou, Jisheng
2014-01-01
The gradient theory for the surface tension of simple fluids and mixtures is rigorously analyzed based on mathematical theory. The finite element approximation of surface tension is developed and analyzed, and moreover, an adaptive finite element method based on a physical-based estimator is proposed and it can be coupled efficiently with Newton\\'s method as well. The numerical tests are carried out both to verify the proposed theory and to demonstrate the efficiency of the proposed method. © 2013 Elsevier B.V. All rights reserved.
Directory of Open Access Journals (Sweden)
Yu-Chai Lai
2015-10-01
Full Text Available Transmedia narratives are a key topic of communication research. Transmedia adaptations occur when a narrator transposes an original work by using various media platforms. Considering pictorial turn, this study employed the intermediality of an animated work that was adapted from an award-winning picture book as an example to propose an analysis for theory building. After examining the literature on transmedia narratives, intermediality, and aesthetic communication, this study proposed analyses for the dimensions of transmedia adaptations of pictorial narratives and aesthetic pole interpretations. Focusing on the three layers of the artistic pole, aesthetic pole, and interactions and effects, this study cited the cases of award-winning picture books and adapted animated works as the basis for reflecting on aesthetic communication. The artistic pole of transmedia adaptation was used as an example of how a narrator employs intermediality by citing the pictures, plot, or art forms from an original work to reinvent structures and then adapts them according to intermediality. If the aesthetic pole views the adapted animated work after reading the picture book or forms an expectation of the adaptation because of intermediality, then when the audience watches the adapted animated work, their imagination could be stimulated by the intermediality (i.e., picture book graphics and scene depictions. For transmedia narrative interaction, the aesthetic pole must “fill blanks” or “negate” to continue to view the adaptation. For filling blanks, because of intermediality, the aesthetic pole must construct an “intracompositional intermediality” to connect with the visual and audio links of the same work or construct “extracompositional intermedialtiy” to associate the original work with the transmedia adaptation. For negation, when viewing the adaptation (i.e., presentation of picture book graphics, added music, or theme song, the aesthetic pole
Beyond the Hedonic Treadmill: Revising the Adaptation Theory of Well-Being
Diener, Ed; Lucas, Richard E.; Napa, Christine
2006-01-01
According to the hedonic treadmill model, good and bad events temporarily affect happiness, but people quickly adapt back to hedonic neutrality. The theory, which has gained widespread acceptance in recent years, implies that individual and societal efforts to increase happiness are doomed to failure. The recent empirical work outlined here…
When do mixotrophs specialize? Adaptive dynamics theory applied to a dynamic energy budget model.
Troost, T.A.; Kooi, B.W.; Kooijman, S.A.L.M.
2005-01-01
In evolutionary history, several events have occurred at which mixotrophs specialized into pure autotrophs and heterotrophs. We studied the conditions under which such events take place, using the Dynamic Energy Budget (DEB) theory for physiological rules of the organisms' metabolism and Adaptive
Seeing Coloured Fruits: Utilisation of the Theory of Adaptive Memory in Teaching Botany
Prokop, Pavol; Fancovicová, Jana
2014-01-01
Plants are characterised by a great diversity of easily observed features such as colours or shape, but children show low interest in learning about them. Here, we integrated modern theory of adaptive memory and evolutionary views of the function of fruit colouration on children's retention of information. Survival-relevant (fruit toxicity) and…
Roy Adaptation Model: integrative review of studies conducted in the light of the theory
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Lays Pinheiro de Medeiros
2015-04-01
Full Text Available Objective: to identify the scientific evidence about the components of the Roy Adaptation Model in the population studied in the light of this theory. Methods: this is an integrative literature review in databases of the Latin-American and Caribbean Center on Health Sciences Information, Medical Literature Analysis and Retrieval System Online, Spanish Bibliographic Index on Health Sciences, Nursing Database, PubMed Central, Cumulative Index to Nursing and Allied Health Literature, Web of Science, and SciVerse Scopus. The sample consists of 20 articles published between 2005 and 2013. Results: the three types of stimuli, 38 of 82 adaptive problems, the four adaptive modes, and the six steps of the nursing process were identified. Conclusion: there is need for further studies on this theory and that address the entire nursing process, culminating in the increase in specific nursing knowledge and affirmation of this science in health.
Counting statistics of chaotic resonances at optical frequencies: Theory and experiments
Lippolis, Domenico; Wang, Li; Xiao, Yun-Feng
2017-07-01
A deformed dielectric microcavity is used as an experimental platform for the analysis of the statistics of chaotic resonances, in the perspective of testing fractal Weyl laws at optical frequencies. In order to surmount the difficulties that arise from reading strongly overlapping spectra, we exploit the mixed nature of the phase space at hand, and only count the high-Q whispering-gallery modes (WGMs) directly. That enables us to draw statistical information on the more lossy chaotic resonances, coupled to the high-Q regular modes via dynamical tunneling. Three different models [classical, Random-Matrix-Theory (RMT) based, semiclassical] to interpret the experimental data are discussed. On the basis of least-squares analysis, theoretical estimates of Ehrenfest time, and independent measurements, we find that a semiclassically modified RMT-based expression best describes the experiment in all its realizations, particularly when the resonator is coupled to visible light, while RMT alone still works quite well in the infrared. In this work we reexamine and substantially extend the results of a short paper published earlier [L. Wang et al., Phys. Rev. E 93, 040201(R) (2016), 10.1103/PhysRevE.93.040201].
DEFF Research Database (Denmark)
Petersen, Nils Holger
2014-01-01
A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice.......A chapter in a book about terminology within the field of medievalism: the chapter discusses the resonance of medieval music and ritual in modern (classical) music culture and liturgical practice....
Kaiplavil, Sreekumar; Rivens, Ian; ter Haar, Gail
2013-07-01
Ultrasound imparted air-recoil resonance (UIAR), a new method for acoustic power estimation, is introduced with emphasis on therapeutic high-intensity focused ultrasound (HIFU) monitoring applications. Advantages of this approach over existing practices include fast response; electrical and magnetic inertness, and hence MRI compatibility; portability; high damage threshold and immunity to vibration and interference; low cost; etc. The angle of incidence should be fixed for accurate measurement. However, the transducer-detector pair can be aligned in any direction with respect to the force of gravity. In this sense, the operation of the device is orientation independent. The acoustic response of a pneumatically coupled pair of Helmholtz resonators, with one of them acting as the sensor head, is used for the estimation of acoustic power. The principle is valid in the case of pulsed/ burst as well as continuous ultrasound exposure, the former being more sensitive and accurate. An electro-acoustic theory has been developed for describing the dynamics of pressure flow and resonance in the system considering various thermo- viscous loss mechanisms. Experimental observations are found to be in agreement with theoretical results. Assuming the window damage threshold (~10 J·mm(-2)) and accuracy of RF power estimation are the upper and lower scale-limiting factors, the performance of the device was examined for an RF power range of 5 mW to 100 W with a HIFU transducer operating at 1.70 MHz, and an average nonlinearity of ~1.5% was observed. The device is also sensitive to sub-milliwatt powers. The frequency response was analyzed at 0.85, 1.70, 2.55, and 3.40 MHz and the results are presented with respective theoretical estimates. Typical response time is in the millisecond regime. Output drift is about 3% for resonant and 5% for nonresonant modes. The principle has been optimized to demonstrate a general-purpose acoustic power meter.
Beghin, Christian; Randriamboarison, Orelien; Hamelin, Michel; Karkoschka, Erich; Sotin, Christophe; Whitten, Robert C.; Berthelier, Jean-Jacques; Grard, Rejean; Simoes, Fernando
2013-01-01
This study presents an approximate model for the atypical Schumann resonance in Titan's atmosphere that accounts for the observations of electromagnetic waves and the measurements of atmospheric conductivity performed with the Huygens Atmospheric Structure and Permittivity, Wave and Altimetry (HASI-PWA) instrumentation during the descent of the Huygens Probe through Titan's atmosphere in January 2005. After many years of thorough analyses of the collected data, several arguments enable us to claim that the Extremely Low Frequency (ELF) wave observed at around 36 Hz displays all the characteristics of the second harmonic of a Schumann resonance. On Earth, this phenomenon is well known to be triggered by lightning activity. Given the lack of evidence of any thunderstorm activity on Titan, we proposed in early works a model based on an alternative powering mechanism involving the electric current sheets induced in Titan's ionosphere by the Saturn's magnetospheric plasma flow. The present study is a further step in improving the initial model and corroborating our preliminary assessments. We first develop an analytic theory of the guided modes that appear to be the most suitable for sustaining Schumann resonances in Titan's atmosphere. We then introduce the characteristics of the Huygens electric field measurements in the equations, in order to constrain the physical parameters of the resonating cavity. The latter is assumed to be made of different structures distributed between an upper boundary, presumably made of a succession of thin ionized layers of stratospheric aerosols spread up to 150 km and a lower quasi-perfect conductive surface hidden beneath the non-conductive ground. The inner reflecting boundary is proposed to be a buried water-ammonia ocean lying at a likely depth of 55-80 km below a dielectric icy crust. Such estimate is found to comply with models suggesting that the internal heat could be transferred upwards by thermal conduction of the crust, while
Mitri, Farid G
2012-08-01
This work presents the general theory of resonance scattering (GTRS) by an elastic spherical shell immersed in a nonviscous fluid and placed arbitrarily in an acoustic beam. The GTRS formulation is valid for a spherical shell of any size and material regardless of its location relative to the incident beam. It is shown here that the scattering coefficients derived for a spherical shell immersed in water and placed in an arbitrary beam equal those obtained for plane wave incidence. Numerical examples for an elastic shell placed in the field of acoustical Bessel beams of different types, namely, a zero-order Bessel beam and first-order Bessel vortex and trigonometric (nonvortex) beams are provided. The scattered pressure is expressed using a generalized partial-wave series expansion involving the beam-shape coefficients (BSCs), the scattering coefficients of the spherical shell, and the half-cone angle of the beam. The BSCs are evaluated using the numerical discrete spherical harmonics transform (DSHT). The far-field acoustic resonance scattering directivity diagrams are calculated for an albuminoidal shell immersed in water and filled with perfluoropropane gas, by subtracting an appropriate background from the total far-field form function. The properties related to the arbitrary scattering are analyzed and discussed. The results are of particular importance in acoustical scattering applications involving imaging and beam-forming for transducer design. Moreover, the GTRS method can be applied to investigate the scattering of any beam of arbitrary shape that satisfies the source-free Helmholtz equation, and the method can be readily adapted to viscoelastic spherical shells or spheres.
Doehrmann, Oliver; Weigelt, Sarah; Altmann, Christian F; Kaiser, Jochen; Naumer, Marcus J
2010-03-03
Information integration across different sensory modalities contributes to object recognition, the generation of associations and long-term memory representations. Here, we used functional magnetic resonance imaging adaptation to investigate the presence of sensory integrative effects at cortical levels as early as nonprimary auditory and extrastriate visual cortices, which are implicated in intermediate stages of object processing. Stimulation consisted of an adapting audiovisual stimulus S(1) and a subsequent stimulus S(2) from the same basic-level category (e.g., cat). The stimuli were carefully balanced with respect to stimulus complexity and semantic congruency and presented in four experimental conditions: (1) the same image and vocalization for S(1) and S(2), (2) the same image and a different vocalization, (3) different images and the same vocalization, or (4) different images and vocalizations. This two-by-two factorial design allowed us to assess the contributions of auditory and visual stimulus repetitions and changes in a statistically orthogonal manner. Responses in visual regions of right fusiform gyrus and right lateral occipital cortex were reduced for repeated visual stimuli (repetition suppression). Surprisingly, left lateral occipital cortex showed stronger responses to repeated auditory stimuli (repetition enhancement). Similarly, auditory regions of interest of the right middle superior temporal gyrus and sulcus exhibited repetition suppression to auditory repetitions and repetition enhancement to visual repetitions. Our findings of crossmodal repetition-related effects in cortices of the respective other sensory modality add to the emerging view that in human subjects sensory integrative mechanisms operate on earlier cortical processing levels than previously assumed.
DEFF Research Database (Denmark)
an impetus or drive to that account: change, innovation, rupture, or discontinuity. Resonances: Historical Essays on Continuity and Change explores the historiographical question of the modes of interrelation between these motifs in historical narratives. The essays in the collection attempt to realize...... theoretical consciousness through historical narrative ‘in practice’, by discussing selected historical topics from Western cultural history, within the disciplines of history, literature, visual arts, musicology, archaeology, philosophy, and theology. The title Resonances indicates the overall perspective...... of the book: how connotations of past meanings may resonate through time, in new contexts, assuming new meanings without surrendering the old....
Zevenhoven, Koos C J; Busch, Sarah; Hatridge, Michael; Oisjöen, Fredrik; Ilmoniemi, Risto J; Clarke, John
2014-03-14
Eddy currents induced by applied magnetic-field pulses have been a common issue in ultra-low-field magnetic resonance imaging. In particular, a relatively large prepolarizing field-applied before each signal acquisition sequence to increase the signal-induces currents in the walls of the surrounding conductive shielded room. The magnetic-field transient generated by the eddy currents may cause severe image distortions and signal loss, especially with the large prepolarizing coils designed for in vivo imaging. We derive a theory of eddy currents in thin conducting structures and enclosures to provide intuitive understanding and efficient computations. We present detailed measurements of the eddy-current patterns and their time evolution in a previous-generation shielded room. The analysis led to the design and construction of a new shielded room with symmetrically placed 1.6-mm-thick aluminum sheets that were weakly coupled electrically. The currents flowing around the entire room were heavily damped, resulting in a decay time constant of about 6 ms for both the measured and computed field transients. The measured eddy-current vector maps were in excellent agreement with predictions based on the theory, suggesting that both the experimental methods and the theory were successful and could be applied to a wide variety of thin conducting structures.
Directory of Open Access Journals (Sweden)
Flegr Jaroslav
2013-01-01
Full Text Available Abstract Punctuational theories of evolution suggest that adaptive evolution proceeds mostly, or even entirely, in the distinct periods of existence of a particular species. The mechanisms of this punctuated nature of evolution suggested by the various theories differ. Therefore the predictions of particular theories concerning various evolutionary phenomena also differ. Punctuational theories can be subdivided into five classes, which differ in their mechanism and their evolutionary and ecological implications. For example, the transilience model of Templeton (class III, genetic revolution model of Mayr (class IV or the frozen plasticity theory of Flegr (class V, suggests that adaptive evolution in sexual species is operative shortly after the emergence of a species by peripatric speciation – while it is evolutionary plastic. To a major degree, i.e. throughout 98-99% of their existence, sexual species are evolutionarily frozen (class III or elastic (class IV and V on a microevolutionary time scale and evolutionarily frozen on a macroevolutionary time scale and can only wait for extinction, or the highly improbable return of a population segment to the plastic state due to peripatric speciation. The punctuational theories have many evolutionary and ecological implications. Most of these predictions could be tested empirically, and should be analyzed in greater depth theoretically. The punctuational theories offer many new predictions that need to be tested, but also provide explanations for a much broader spectrum of known biological phenomena than classical gradualistic evolutionary theories. Reviewers This article was reviewed by Claus Wilke, Pierre Pantarotti and David Penny (nominated by Anthony Poole.
Green’s function theory of ferromagnetic resonance in magnetic superlattices with damping
International Nuclear Information System (INIS)
Qiu, R.K.; Guo, F.F.; Zhang, Z.D.
2016-01-01
We explore a quantum Green’s-function method to study the resonance absorption of magnetic materials. The relationship between the resonance magnon (spin wave) density and the resonance frequency of a superlattice consisting of two magnetic layers with damping and antiferromagnetic interlayer exchange coupling is studied. The effects of temperature, interlayer coupling, anisotropy, external magnetic field and damping on the the resonance frequency and resonance magnon density are investigated. The resonance excitation probability for a magnon is proportional to the resonance magnon density. In the classic methods, the imaginary part of magnetic permeability represents the resonance absorption in magnetic materials. In the quantum approach, the resonance magnon density can be used to estimate the strength of the resonance absorption. In the present work, a quantum approach is developed to study resonance absorption of magnetic materials and the results show the method to obtain a magnetic multilayered materials with both high resonance frequency and high resonance absorption.
Holzer, Christof; Klopper, Wim
2017-11-01
A method for calculating intermolecular induction and dispersion energies based on a GW description of the monomers and employing response functions from the Bethe-Salpeter equation is proposed. Calculations on a test set of 10 weakly bound complexes with GW-based symmetry-adapted perturbation theory (GW-SAPT) show an improved performance in comparison with symmetry-adapted perturbation theory based on density-functional theory (DFT-SAPT).
Hadronic decays of the tau lepton : τ- → (πππ)- ντ within Resonance Chiral Theory
International Nuclear Information System (INIS)
Gomez Dumm, D.; Pich, A.; Portoles, J.
2006-01-01
τ decays into hadrons foresee the study of the hadronization of vector and axial-vector QCD currents, yielding relevant information on the dynamics of the resonances entering into the processes. We analyse τ → πππντ decays within the framework of the Resonance Chiral Theory, comparing this theoretical scheme with the experimental data, namely ALEPH spectral function and branching ratio. Hence we get values for the mass and on-shell width of the a 1 (1260) resonance, and provide the structure functions that have been measured by OPAL and CLEO-II
Bhatia, Anand K.
2008-01-01
Applications of the hybrid theory to the scattering of electrons from Ile+ and Li++ and resonances in these systems, A. K. Bhatia, NASA/Goddard Space Flight Center- The Hybrid theory of electron-hydrogen elastic scattering [I] is applied to the S-wave scattering of electrons from He+ and Li++. In this method, both short-range and long-range correlations are included in the Schrodinger equation at the same time. Phase shifts obtained in this calculation have rigorous lower bounds to the exact phase shifts and they are compared with those obtained using the Feshbach projection operator formalism [2], the close-coupling approach [3], and Harris-Nesbet method [4]. The agreement among all the calculations is very good. These systems have doubly-excited or Feshbach resonances embedded in the continuum. The resonance parameters for the lowest ' S resonances in He and Li+ are calculated and they are compared with the results obtained using the Feshbach projection operator formalism [5,6]. It is concluded that accurate resonance parameters can be obtained by the present method, which has the advantage of including corrections due to neighboring resonances and the continuum in which these resonances are embedded.
International Nuclear Information System (INIS)
Biglari, H.; Chen, L.
1991-10-01
A complete theory of wave-particle interactions is presented whereby both circulating and trapped energetic ions can destabilize kinetic ballooning modes in tokamaks. Four qualitatively different types of resonances, involving wave-precessional drift, wave-transit, wave-bounce, and precessional drift-bounce interactions, are identified, and the destabilization potential of each is assessed. For a characteristic slowing-down distribution function, the dominant interaction is that which taps those resonant ions with the highest energy. Implications of the theory for present and future generation fusion experiments are discussed. 16 refs
Backward wave oscillators with rippled wall resonators: Analytic theory and numerical simulation
International Nuclear Information System (INIS)
Swegle, J.A.; Poukey, J.W.
1985-01-01
The 3-D analytic theory is based on the approximation that the device is infinitely long. In the absence of an electron beam, the theory is exact and allows us to compute the dispersion characteristics of the cold structure. With the inclusion of a thin electron beam, we can compute the growth rates resulting from the interaction between a waveguide mode of the structure and the slower space charge wave on the beam. In the limit of low beam currents, the full dispersion relation based on an electromagnetic analysis can be placed in correspondence with the circuit theory of Pierce. Numerical simulations permit us to explore the saturated, large amplitude operating regime for TM axisymmetric modes. The scaling of operating frequency, peak power, and operating efficiency with beam and resonator parameters is examined. The analytic theory indicates that growth rates are largest for the TM 01 modes and decrease with both the radial and azimuthal mode numbers. Another interesting trend is that for a fixed cathode voltage and slow wave structure, growth rates peak for a beam current below the space charge limiting value and decrease for both larger and smaller currents. The simulations show waves that grow from noise without any input signal, so that the system functions as an oscillator. The TM 01 mode predominates in all simulations. While a minimum device length is required for the start of oscillations, it appears that if the slow wave structure is too long, output power is decreased by a transfer of wave energy back to the electrons. Comparisons have been made between the analytical and numerical results, as well as with experimental data obtained at Sandia National Laboratories
Arias, Rodrigo; Mills, Douglas
2008-03-01
Recent experiments explore the ferromagnetic resonance (FR) response of nanodiscs incorporated into nanopillars, where a DC spin torque current has a small AC component superimposed. For such a circular perpendicularly magnetized disc, we develop the theory of the FR response via AC current. Earlier we discussed the vortex state induced by the DC Oersted field in such a sample, and the nature of the spin waves in the presence of the vortex^2. The present study explores the linear response of the disc, when a small AC current is superimposed on the DC current. A Green's function approach allows us to describe the linear response of the system. We argue that the AC component of the Oersted field is responsible for spin wave excitation; the modes excited thus differ from those observed in ferromagnetic resonance studies via microwaves. We shall present calculations which explore the spectrum and eigenvectors of modes excited by modulation of the DC current, their width as a function of DC current, and their intensity. ^2R. E. Arias and D. L. Mills, Phys. Rev. B75, 214404 (2007).
Quantum Information Biology: From Theory of Open Quantum Systems to Adaptive Dynamics
Asano, Masanari; Basieva, Irina; Khrennikov, Andrei; Ohya, Masanori; Tanaka, Yoshiharu; Yamato, Ichiro
This chapter reviews quantum(-like) information biology (QIB). Here biology is treated widely as even covering cognition and its derivatives: psychology and decision making, sociology, and behavioral economics and finances. QIB provides an integrative description of information processing by bio-systems at all scales of life: from proteins and cells to cognition, ecological and social systems. Mathematically QIB is based on the theory of adaptive quantum systems (which covers also open quantum systems). Ideologically QIB is based on the quantum-like (QL) paradigm: complex bio-systems process information in accordance with the laws of quantum information and probability. This paradigm is supported by plenty of statistical bio-data collected at all bio-scales. QIB re ects the two fundamental principles: a) adaptivity; and, b) openness (bio-systems are fundamentally open). In addition, quantum adaptive dynamics provides the most generally possible mathematical representation of these principles.
Directory of Open Access Journals (Sweden)
Joshua Rodewald
2016-10-01
Full Text Available Supply networks existing today in many industries can behave as complex adaptive systems making them more difficult to analyze and assess. Being able to fully understand both the complex static and dynamic structures of a complex adaptive supply network (CASN are key to being able to make more informed management decisions and prioritize resources and production throughout the network. Previous efforts to model and analyze CASN have been impeded by the complex, dynamic nature of the systems. However, drawing from other complex adaptive systems sciences, information theory provides a model-free methodology removing many of those barriers, especially concerning complex network structure and dynamics. With minimal information about the network nodes, transfer entropy can be used to reverse engineer the network structure while local transfer entropy can be used to analyze the network structure’s dynamics. Both simulated and real-world networks were analyzed using this methodology. Applying the methodology to CASNs allows the practitioner to capitalize on observations from the highly multidisciplinary field of information theory which provides insights into CASN’s self-organization, emergence, stability/instability, and distributed computation. This not only provides managers with a more thorough understanding of a system’s structure and dynamics for management purposes, but also opens up research opportunities into eventual strategies to monitor and manage emergence and adaption within the environment.
Elazab, Ahmed; Wang, Changmiao; Jia, Fucang; Wu, Jianhuang; Li, Guanglin; Hu, Qingmao
2015-01-01
An adaptively regularized kernel-based fuzzy C-means clustering framework is proposed for segmentation of brain magnetic resonance images. The framework can be in the form of three algorithms for the local average grayscale being replaced by the grayscale of the average filter, median filter, and devised weighted images, respectively. The algorithms employ the heterogeneity of grayscales in the neighborhood and exploit this measure for local contextual information and replace the standard Euclidean distance with Gaussian radial basis kernel functions. The main advantages are adaptiveness to local context, enhanced robustness to preserve image details, independence of clustering parameters, and decreased computational costs. The algorithms have been validated against both synthetic and clinical magnetic resonance images with different types and levels of noises and compared with 6 recent soft clustering algorithms. Experimental results show that the proposed algorithms are superior in preserving image details and segmentation accuracy while maintaining a low computational complexity.
Hanson-Heine, Magnus W. D.; George, Michael W.; Besley, Nicholas A.
2018-03-01
The non-resonant X-ray emission spectroscopy of fullerenes and carbon nanotubes is studied with density functional theory in conjunction with short-range corrected functionals. For C60 and C70 the X-ray emission spectra are insensitive to modest structural changes, and absorption onto the fullerene cage has the greatest effect with a broader less structured band observed with the high energy π band reduced in intensity. For carbon nanotubes the X-ray emission spectra are shown to be weakly dependent on the length and chirality of the nanotube. However, some variation with the diameter of the tube is observed in both resonant and non-resonant spectra.
Indian Academy of Sciences (India)
maceutical, paper, food, dyes, petrochemi- cals, pigments, etc., to identify molecules, to monitor reaction products and so on. One of the most spectacular contributions of NMR has been in the development of magnetic resonance imaging (MRI), a method that has today revolutionized diagnosis and treatment of diseases in ...
Li, Zhendong; Liu, Wenjian
2010-08-14
The spin-adaptation of single-reference quantum chemical methods for excited states of open-shell systems has been nontrivial. The primary reason is that the configuration space, generated by a truncated rank of excitations from only one component of a reference multiplet, is spin-incomplete. Those "missing" configurations are of higher ranks and can, in principle, be recaptured by a particular class of excitation operators. However, the resulting formalisms are then quite involved and there are situations [e.g., time-dependent density functional theory (TD-DFT) under the adiabatic approximation] that prevent one from doing so. To solve this issue, we propose here a tensor-coupling scheme that invokes all the components of a reference multiplet (i.e., a tensor reference) rather than increases the excitation ranks. A minimal spin-adapted n-tuply excited configuration space can readily be constructed by tensor products between the n-tuple tensor excitation operators and the chosen tensor reference. Further combined with the tensor equation-of-motion formalism, very compact expressions for excitation energies can be obtained. As a first application of this general idea, a spin-adapted open-shell random phase approximation is first developed. The so-called "translation rule" is then adopted to formulate a spin-adapted, restricted open-shell Kohn-Sham (ROKS)-based TD-DFT (ROKS-TD-DFT). Here, a particular symmetry structure has to be imposed on the exchange-correlation kernel. While the standard ROKS-TD-DFT can access only excited states due to singlet-coupled single excitations, i.e., only some of the singly excited states of the same spin (S(i)) as the reference, the new scheme can capture all the excited states of spin S(i)-1, S(i), or S(i)+1 due to both singlet- and triplet-coupled single excitations. The actual implementation and computation are very much like the (spin-contaminated) unrestricted Kohn-Sham-based TD-DFT. It is also shown that spin-contaminated spin
Spin-adapted open-shell time-dependent density functional theory. II. Theory and pilot application.
Li, Zhendong; Liu, Wenjian; Zhang, Yong; Suo, Bingbing
2011-04-07
The excited states of open-shell systems calculated by unrestricted Kohn-Sham-based time-dependent density functional theory (U-TD-DFT) are often heavily spin-contaminated and hence meaningless. This is solved ultimately by the recently proposed spin-adapted time-dependent density functional theory (TD-DFT) (S-TD-DFT) [J. Chem. Phys. 133, 064106 (2010)]. Unlike the standard restricted open-shell Kohn-Sham-based TD-DFT (R-TD-DFT) which can only access the singlet-coupled single excitations, the S-TD-DFT can capture both the singlet- and triplet-coupled single excitations with the same computational effort as the U-TD-DFT. The performances of the three approaches (U-TD-DFT, R-TD-DFT, and S-TD-DFT) are compared for both the spin-conserving and spin-flip excitations of prototypical open-shell systems, the nitrogen (N(2)(+)) and naphthalene (C(10)H(8)(+)) cations. The results show that the S-TD-DFT gives rise to balanced descriptions of excited states of open-shell systems.
Directory of Open Access Journals (Sweden)
Lars Neeb
2013-08-01
Full Text Available Background: The main safety aspect in the use of stroke thrombolysis and in clinical trials of new pharmaceutical or interventional stroke therapies is the incidence of hemorrhagic transformation (HT after treatment. The computed tomography (CT-based classification of the European Cooperative Acute Stroke Study (ECASS distinguishes four categories of HTs. An HT can range from a harmless spot of blood accumulation to a symptomatic space-occupying parenchymal bleeding associated with a massive deterioration of symptoms and clinical prognosis. In magnetic resonance imaging (MRI HTs are often categorized using the ECASS criteria although this classification has not been validated in MRI. We developed MRI-specific criteria for the categorization of HT and sought to assess its diagnostic reliability in a retrospective study. Methods: Consecutive acute ischemic stroke patients, who had received a 3-tesla MRI before and 12-36 h after thrombolysis, were screened retrospectively for an HT of any kind in post-treatment MRI. Intravenous tissue plasminogen activator was given to all patients within 4.5 h. HT categorization was based on a simultaneous read of 3 different MRI sequences (fluid-attenuated inversion recovery, diffusion-weighted imaging and T2* gradient-recalled echo. Categorization of HT in MRI accounted for the various aspects of the imaging pattern as the shape of the bleeding area and signal intensity on each sequence. All data sets were independently categorized in a blinded fashion by 3 expert and 3 resident observers. Interobserver reliability of this classification was determined for all observers together and for each group separately by calculating Kendall's coefficient of concordance (W. Results: Of the 186 patients screened, 39 patients (21% had an HT in post-treatment MRI and were included for the categorization of HT by experts and residents. The overall agreement of HT categorization according to the modified classification was
Zeroth-order resonance phenomenon in an acoustic composite right/left-handed metamaterial resonator.
Kim, Wan-Gu; Kang, Hwi Suk; Yoon, Suk Wang; Lee, Kang Il
2017-10-01
This study proposes an acoustic theory that describes the resonance phenomena in a resonator made of acoustic composite right/left-handed (CRLH) metamaterials, and verifies it through numerical simulation. The established theory for a microwave CRLH metamaterial resonator is adapted to explain the resonance phenomena in an acoustic CRLH metamaterial resonator. In particular, attention is focused on the zeroth-order resonance phenomenon which has several interesting properties. When a resonator is composed of a CRLH metamaterial, a resonance with a flat acoustic field distribution may occur at one of the frequencies where the wavenumber becomes zero. This resonance is called zeroth-order resonance. Through numerical simulation, such unusual resonance phenomenon in acoustics is observed in more detail and the proposed theory is verified. The results of the theory and the numerical simulation clearly show that zeroth-order resonance can exist at those frequencies where the acoustic field distribution is flat due to infinite wavelength. It is also shown that the resonance frequency and the Q factor of this resonance depend on the boundary condition at both ends of the resonator, and they basically do not change even when the number of units is reduced or increased.
Lee, C
1988-03-01
Two typologies of family process, Olson's Circumplex Model and the Beavers Systems Model, are discussed, focusing particularly upon their definitions of family adaptability. It is argued that the two typologies are not simply "separate but equal" (11), but, rather, that there is an ambiguity in the Circumplex Model that disguises a fundamental theoretical overlap between the two. Olson's definition of adaptability is founded upon the concepts of morphogenesis and change; Beavers builds upon the concepts of negentropy and competence. It may be shown, however, that both understandings are necessitated by the theoretical writings of Olson and his colleagues. The nature of this ambiguity in the Circumplex Model is critically explored, and a higher-order model that attempts to synthesize these two theories is proposed.
Adaptability of the Logistics System in National Economic Mobilization Based on Blocking Flow Theory
Directory of Open Access Journals (Sweden)
Xiangyuan Jing
2014-01-01
Full Text Available In the process of national economic mobilization, the logistics system usually suffers from negative impact and/or threats of such emergency events as wars and accidents, which implies that adaptability of the logistics system directly determines realization of economic mobilization. And where the real-time rescue operation is concerned, heavy traffic congestion is likely to cause a great loss of or damage to human beings and their properties. To deal with this situation, this article constructs a blocking-resistance optimum model and an optimum restructuring model based on blocking flow theories, of which both are illustrated by numerical cases and compared in characteristics and application. The design of these two models is expected to eliminate or alleviate the congestion situation occurring in the logistics system, thus effectively enhancing its adaptability in the national economic mobilization process.
The Role of Theory Adaptation in the Making of a Reference Discipline
DEFF Research Database (Denmark)
Kjærgaard, Annemette; Vendelø, Morten Thanning
2015-01-01
Information Systems (IS) scholars repeatedly debate the nature of the IS discipline. A series of articles have debated whether the IS field has become a reference discipline. While many scholars have argued this question from a perceptual point of view, we address it by examining the role of theo...... adaptation, have a higher probability of being referenced by other disciplines. Finally, we discuss the implications of the manner in which IS scholars borrow theory regarding the IS discipline's prospects of becoming a reference discipline....
Indian Academy of Sciences (India)
Teaching and Learning 'Genetics with Drosophila. 3. Pattern of Inheritance of Autosome and Sex . Chromosome Linked Genes/Characters. Phenotypic characters or traits are determined by genes, and genes are physically located on different chromosomes. This is the basic tenet of the chromosomal theory of inheritance.
A Study of ρ-ω Mixing in Resonance Chiral Theory
Chen, Yun-Hua; Yao, De-Liang; Zheng, Han-Qing
2018-01-01
The strong and electromagnetic corrections to ρ-ω mixing are calculated using an SU(2) version of resonance chiral theory up to next-to-leading orders in 1/{N}C expansion, respectively. Up to our accuracy, the effect of the momentum dependence of ρ-ω mixing is incorporated due to the inclusion of loop contributions. We analyze the impact of ρ-ω mixing on the pion vector form factor by performing numerical fit to the data extracted from {e}+{e}-\\to {π }+{π }- and τ \\to {ν }τ 2π , while the decay width of ω \\to {π }+{π }- is taken into account as a constraint. It is found that the momentum dependence is significant in a good description of the experimental data. In addition, based on the fitted values of the involved parameters, we analyze the decay width of ω \\to {π }+{π }-, which turns out to be highly dominated by the ρ-ω mixing effect. Supported in part by the Fundamental Research Funds for the Central Universities under Grant No. 06500077, the Spanish Ministerio de Economía y Competitividad and the European Regional Development Fund, under Grant Nos. FIS2014-51948-C2-1-P, FIS2014-51948-C2-2-P, SEV-2014-0398, and Generalitat Valenciana under Grant No. PROMETEOII/2014/0068
Research on the output bit error rate of 2DPSK signal based on stochastic resonance theory
Yan, Daqin; Wang, Fuzhong; Wang, Shuo
2017-12-01
Binary differential phase-shift keying (2DPSK) signal is mainly used for high speed data transmission. However, the bit error rate of digital signal receiver is high in the case of wicked channel environment. In view of this situation, a novel method based on stochastic resonance (SR) is proposed, which is aimed to reduce the bit error rate of 2DPSK signal by coherent demodulation receiving. According to the theory of SR, a nonlinear receiver model is established, which is used to receive 2DPSK signal under small signal-to-noise ratio (SNR) circumstances (between -15 dB and 5 dB), and compared with the conventional demodulation method. The experimental results demonstrate that when the input SNR is in the range of -15 dB to 5 dB, the output bit error rate of nonlinear system model based on SR has a significant decline compared to the conventional model. It could reduce 86.15% when the input SNR equals -7 dB. Meanwhile, the peak value of the output signal spectrum is 4.25 times as that of the conventional model. Consequently, the output signal of the system is more likely to be detected and the accuracy can be greatly improved.
Babbs, Charles F
2011-01-01
To explore the fundamental biomechanics of sound frequency transduction in the cochlea, a two-dimensional analytical model of the basilar membrane was constructed from first principles. Quantitative analysis showed that axial forces along the membrane are negligible, condensing the problem to a set of ordered one-dimensional models in the radial dimension, for which all parameters can be specified from experimental data. Solutions of the radial models for asymmetrical boundary conditions produce realistic deformation patterns. The resulting second-order differential equations, based on the original concepts of Helmholtz and Guyton, and including viscoelastic restoring forces, predict a frequency map and amplitudes of deflections that are consistent with classical observations. They also predict the effects of an observation hole drilled in the surrounding bone, the effects of curvature of the cochlear spiral, as well as apparent traveling waves under a variety of experimental conditions. A quantitative rendition of the classical Helmholtz-Guyton model captures the essence of cochlear mechanics and unifies the competing resonance and traveling wave theories.
Quantitative Reappraisal of the Helmholtz-Guyton Resonance Theory of Frequency Tuning in the Cochlea
Directory of Open Access Journals (Sweden)
Charles F. Babbs
2011-01-01
Full Text Available To explore the fundamental biomechanics of sound frequency transduction in the cochlea, a two-dimensional analytical model of the basilar membrane was constructed from first principles. Quantitative analysis showed that axial forces along the membrane are negligible, condensing the problem to a set of ordered one-dimensional models in the radial dimension, for which all parameters can be specified from experimental data. Solutions of the radial models for asymmetrical boundary conditions produce realistic deformation patterns. The resulting second-order differential equations, based on the original concepts of Helmholtz and Guyton, and including viscoelastic restoring forces, predict a frequency map and amplitudes of deflections that are consistent with classical observations. They also predict the effects of an observation hole drilled in the surrounding bone, the effects of curvature of the cochlear spiral, as well as apparent traveling waves under a variety of experimental conditions. A quantitative rendition of the classical Helmholtz-Guyton model captures the essence of cochlear mechanics and unifies the competing resonance and traveling wave theories.
Energy Technology Data Exchange (ETDEWEB)
Luo, Shaohua [The Jiangsu Key Laboratory of Advanced Manufacturing Technology, Huaiyin Institute of Technology, Huai’an 223003 (China); School of Automation, Chongqing University, Chongqing 400044 (China); Sun, Quanping; Cheng, Wei [The Jiangsu Key Laboratory of Advanced Manufacturing Technology, Huaiyin Institute of Technology, Huai’an 223003 (China)
2016-04-15
This paper addresses chaos control of the micro-electro- mechanical resonator by using adaptive dynamic surface technology with extended state observer. To reveal the mechanism of the micro- electro-mechanical resonator, the phase diagrams and corresponding time histories are given to research the nonlinear dynamics and chaotic behavior, and Homoclinic and heteroclinic chaos which relate closely with the appearance of chaos are presented based on the potential function. To eliminate the effect of chaos, an adaptive dynamic surface control scheme with extended state observer is designed to convert random motion into regular motion without precise system model parameters and measured variables. Putting tracking differentiator into chaos controller solves the ‘explosion of complexity’ of backstepping and poor precision of the first-order filters. Meanwhile, to obtain high performance, a neural network with adaptive law is employed to approximate unknown nonlinear function in the process of controller design. The boundedness of all the signals of the closed-loop system is proved in theoretical analysis. Finally, numerical simulations are executed and extensive results illustrate effectiveness and robustness of the proposed scheme.
An Adaptive Resonant Regulator for Single-phase Grid-Tied VSCs
DEFF Research Database (Denmark)
Golestan, Saeed; Ebrahimzadeh, Esmaeil; Guerrero, Josep M.
2018-01-01
is at its nominal value. In the presence of frequency drifts, nevertheless, a zero tracking error may not be guaranteed. To deal with this problem, the resonance frequency of the PR controller may be updated using the frequency estimated by the synchronization unit, which is often a PLL. In recent years......The proportional-resonant (PR) controller is highly popular for controlling grid-connected voltage source converters. The resonant part of this controller provides an infinite gain at the nominal frequency and, in this way, ensures a zero steady-state tracking error when the grid frequency......, however, there is a growing attention towards eliminating the need for a dedicated synchronization unit and designing integrated synchronization and control structures as they benefit from a simpler and more compact structure. In this letter, based on a structural resemblance between a resonant current...
International Nuclear Information System (INIS)
Castejon M, F.
1989-01-01
The study of the Linear Theory microwave propagation and absorption in the the frequency range of electron cyclotron resonance, in a magnetized plasma, is developed. This study is particularized to the flexible heliac TJ-II, whose main characteristics are dsetailed in a memory chapter, as an interesting case example for its peculiar magnetic configuration. As a preliminary phase, a cold plasma model is useds to analyze the resonance accessibility and the approximated density limits which will be obtainable in each electron cyclotron resonance harmonic. This analysis was used to find the suitable positions for the microwave injection in TJ-II. An analytical weakly relativistic model for the dielectric tensor is developed, valid for oblique propagation, that takes account of the effect of superthermal electrons. Second order Larmor radius effects are included, so that the Quasi-Electrostatic branch of X mode can be studied. A numerical study is then presented on the absorption properties of TJ-II. Since the TJ-II geometry is complex and its magnetic field distribution is very different from that of a tokamak, ray tracing calculations are necessary to consider refraction effects. The ray tracing codse RAYS, developed in the Oak Ridge National Laboratory (U.S.A.), was take and adapted to the helical magnetic configuration of the TJ-II. The absorption model described above was then included in RAYS. For completeness, an introduction to the Quasi Linear Theory, natural prolongation of this work, is included at the end of the memory, ands the effects of taking into account the quasi linear evolution of the distribution function are described. (Author)
Ma, Qiang; Huang, Dawen; Yang, Jianhua
The theory of general scale transformation (GST) is put forward and used in the second-order underdamped bistable system to extract weak signal features submerged into strong noise. An adaptive stochastic resonance (SR) with GST is proposed and realized by the quantum particle swarm optimization (QPSO) algorithm. The harmonic signal and experimental signal are considered to compare GST with normalized scale transformation (NST) in the second-order system. The results show that detection effect of the adaptive SR with GST is better than the NST SR. In addition, the output signal-to-noise ratio (SNR) is significantly improved in the GST method. Meanwhile, the dependence of the signal extraction efficiency on the noise intensity is researched. The output SNR is decreased with the increase of the noise intensity in two methods. However, the proposed method is always superior to the NST. Moreover, the superiority of the Brown particle oscillation in the single well is discussed. The proposed method has certain reference value in the extraction of the weak signal under the strong noise background.
Balas, Mark J.; Thapa Magar, Kaman S.; Frost, Susan A.
2013-01-01
A theory called Adaptive Disturbance Tracking Control (ADTC) is introduced and used to track the Tip Speed Ratio (TSR) of 5 MW Horizontal Axis Wind Turbine (HAWT). Since ADTC theory requires wind speed information, a wind disturbance generator model is combined with lower order plant model to estimate the wind speed as well as partial states of the wind turbine. In this paper, we present a proof of stability and convergence of ADTC theory with lower order estimator and show that the state feedback can be adaptive.
Sutter, Kiplangat
This thesis illustrates the utilization of Density functional theory (DFT) in calculations of gas and solution phase Nuclear Magnetic Resonance (NMR) properties of light and heavy nuclei. Computing NMR properties is still a challenge and there are many unknown factors that are still being explored. For instance, influence of hydrogen-bonding; thermal motion; vibration; rotation and solvent effects. In one of the theoretical studies of 195Pt NMR chemical shift in cisplatin and its derivatives illustrated in Chapter 2 and 3 of this thesis. The importance of representing explicit solvent molecules explicitly around the Pt center in cisplatin complexes was outlined. In the same complexes, solvent effect contributed about half of the J(Pt-N) coupling constant. Indicating the significance of considering the surrounding solvent molecules in elucidating the NMR measurements of cisplatin binding to DNA. In chapter 4, we explore the Spin-Orbit (SO) effects on the 29Si and 13C chemical shifts induced by surrounding metal and ligands. The unusual Ni, Pd, Pt trends in SO effects to the 29Si in metallasilatrane complexes X-Si-(mu-mt)4-M-Y was interpreted based on electronic and relativistic effects rather than by structural differences between the complexes. In addition, we develop a non-linear model for predicting NMR SO effects in a series of organics bonded to heavy nuclei halides. In chapter 5, we extend the idea of "Chemist's orbitals" LMO analysis to the quantum chemical proton NMR computation of systems with internal resonance-assisted hydrogen bonds. Consequently, we explicitly link the relationship between the NMR parameters related to H-bonded systems and intuitive picture of a chemical bond from quantum calculations. The analysis shows how NMR signatures characteristic of H-bond can be explained by local bonding and electron delocalization concepts. One shortcoming of some of the anti-cancer agents like cisplatin is that they are toxic and researchers are looking for
Directory of Open Access Journals (Sweden)
Roohollah Roozbeh
2017-06-01
Full Text Available Hollywood has been fascinated with the Thousand and One Nights. It has adapted it from the very outset of Cinema itself. Based on Linda Hutcheon’s (2006 A Theory of Adaptation, this paper tries to examine Rawlins’ Arabian Nights (1942 to see how Hollywood adapts from this Oriental work. Hutcheon argues that adapters adapt differently; some adapt to pay tribute and homage to the author, some adapt because they want to make money; some adapt to gain cultural authority and canonicity; others adapt to critique and subvert the ideology of the text. In this paper we will argue that Hollywood occupies the fourth category in adapting Thousand and One Nights in Arabian Nights directed by Rawlins, that is to say Hollywood seeks to subvert the ideology of the text and critique what it stands for and what the text stands for is the East and mostly Arabic culture. To do that, Hollywood does not indigenize the culture of the East and critiques the culture of the Arabs through the tropes of belly-dance, veil, and harem. The methodology of this article is wholly based on Edward Said’s theory of Orientalism in his book Orientalism.
Ruoff, Jürgen; Würslin, Christian; Graf, Hansjörg; Schick, Fritz
2012-05-01
Prediction of interactions between the radiofrequency electromagnetic field in magnetic resonance scanners and electrically conductive material surrounded by tissue plays an increasing role for magnetic resonance safety. Testing of conductive implants or instruments is usually performed by standardized experimental setups and temperature measurements at distinct geometrical points, which cannot always reflect worst-case situations. A finite element method based on Matlab (The Mathworks, Natick, MA) and the finite element method program Comsol Multiphysics (Stockholm, Sweden) with a spatially highly variable mesh size solving Maxwell's full-wave equations was applied for a comprehensive simulation of the complete geometrical arrangement of typical birdcage radiofrequency coils loaded with small conductive structures in a homogenous medium. Conductive implants like rods of variable length and closed and open ring structures, partly exhibiting electromagnetic resonance behavior, were modeled and evaluated regarding the distribution of the B(1)- and E-field, induced currents and specific absorption rates. Numerical simulations corresponded well with experiments using a spin-echo sequence for visualization of marked B(1)-field inhomogeneities. Even resonance effects in conductive rods and open rings with suitable geometry were depicted accurately. The proposed method has high potential for complementation or even replacement of common experimental magnetic resonance compatibility measurements. Copyright © 2011 Wiley Periodicals, Inc.
Decision Support for Energy Contracts Negotiation with Game Theory and Adaptive Learning
Directory of Open Access Journals (Sweden)
Tiago Pinto
2015-09-01
Full Text Available This paper presents a decision support methodology for electricity market players’ bilateral contract negotiations. The proposed model is based on the application of game theory, using artificial intelligence to enhance decision support method’s adaptive features. This model is integrated in AiD-EM (Adaptive Decision Support for Electricity Markets Negotiations, a multi-agent system that provides electricity market players with strategic behavior capabilities to improve their outcomes from energy contracts’ negotiations. Although a diversity of tools that enable the study and simulation of electricity markets has emerged during the past few years, these are mostly directed to the analysis of market models and power systems’ technical constraints, making them suitable tools to support decisions of market operators and regulators. However, the equally important support of market negotiating players’ decisions is being highly neglected. The proposed model contributes to overcome the existing gap concerning effective and realistic decision support for electricity market negotiating entities. The proposed method is validated by realistic electricity market simulations using real data from the Iberian market operator—MIBEL. Results show that the proposed adaptive decision support features enable electricity market players to improve their outcomes from bilateral contracts’ negotiations.
Parton Theory of Magnetic Polarons: Mesonic Resonances and Signatures in Dynamics
Grusdt, F.; Kánasz-Nagy, M.; Bohrdt, A.; Chiu, C. S.; Ji, G.; Greiner, M.; Greif, D.; Demler, E.
2018-01-01
When a mobile hole is moving in an antiferromagnet it distorts the surrounding Néel order and forms a magnetic polaron. Such interplay between hole motion and antiferromagnetism is believed to be at the heart of high-temperature superconductivity in cuprates. In this article, we study a single hole described by the t -Jz model with Ising interactions between the spins in two dimensions. This situation can be experimentally realized in quantum gas microscopes with Mott insulators of Rydberg-dressed bosons or fermions, or using polar molecules. We work at strong couplings, where hole hopping is much larger than couplings between the spins. In this regime we find strong theoretical evidence that magnetic polarons can be understood as bound states of two partons, a spinon and a holon carrying spin and charge quantum numbers, respectively. Starting from first principles, we introduce a microscopic parton description which is benchmarked by comparison with results from advanced numerical simulations. Using this parton theory, we predict a series of excited states that are invisible in the spectral function and correspond to rotational excitations of the spinon-holon pair. This is reminiscent of mesonic resonances observed in high-energy physics, which can be understood as rotating quark-antiquark pairs carrying orbital angular momentum. Moreover, we apply the strong-coupling parton theory to study far-from-equilibrium dynamics of magnetic polarons observable in current experiments with ultracold atoms. Our work supports earlier ideas that partons in a confining phase of matter represent a useful paradigm in condensed-matter physics and in the context of high-temperature superconductivity in particular. While direct observations of spinons and holons in real space are impossible in traditional solid-state experiments, quantum gas microscopes provide a new experimental toolbox. We show that, using this platform, direct observations of partons in and out of equilibrium are
Using self-organizing maps adaptive resonance theory (CARTMAP) for manufacturing feature recognition
Yu, Jason S.; Dagli, Cihan H.
1993-10-01
The invariant image preprocessing of moment invariants generates an invariant representation of object features which are insensitive to position, orientation, size, illusion, and contrast change. In this study ARTMAP is used for 3-D object recognition of manufacturing parts through these invariant characteristics. The analog of moment invariants created through the image preprocessing is interpreted by a binary code which is used to predict the manufacturing part through ARTMAP.
COMPOSITE MATERIALS' CONDITION CLASSIFIER BASED ON NEURAL NETWORK OF ADAPTIVE RESONANCE THEORY
Directory of Open Access Journals (Sweden)
В. Єременко
2012-04-01
Full Text Available In this article proposed to use a modified neural network Fuzzy-ART for classification of thetechnical condition of composite materials. This neural network is used as a part of nondestructivetesting system to perform diagnosis of composite materials and provides cluster analysis andclassification of units under test. The advantage of the described neural network and the system ingeneral is its flexible architecture, high performance and high reliability of data processing
Mean-field resonating-valence-bond theory for unpaired π-electrons in benzenoid carbon species
Ivanciuc, O.; Bytautas, L.; Klein, D. J.
2002-03-01
A qualitative resonance-theoretic view is presented for the description of a variety of conjugated π-network species identified with "subgraphs" (either finite or infinite) of the graphite network. Within the framework of this resonance theory, simple rules are described to provide qualitative information: On ground-state spin multiplicities; on patterns of ground-state spin density; and on exchange splittings to low-lying "spin-flipped" excited states. Beyond ordinary benzenoid molecules, illustrative applications are noted to a diversity of extended species, including: Differently structured edges on semi-infinite graphite; corner structures where edges along different directions meet; conjugated polymer-strip ends; and local defect vacancy structures in extended graphite. The variety of simple resonance-theoretic predictions are compared against a semiempirical unrestricted Hartree-Fock view of some quantitative tight-binding molecular-orbital-theoretic computations. Agreement in predictions from the resonance- and band-theoretic viewpoints is taken to engender reliability of the so coincident predictions. A traditional organic chemical resonance-theoretic view is thence conveniently reformulated and brought to bear on several extended nano-structured systems to reveal systematic patterns of π-electronic behavior.
Tsay, Crystal Han-Huei
2012-01-01
The contemporary business world demands adaptive individuals (Friedman & Wyman, 2005). Adaptation is essential for any life transition. It often involves developing coping mechanisms, strategies, and seeking of social support. Adaptation occurs in many settings from moving to a new culture, taking a new job, starting or finishing an…
Parrish, Robert M; Gonthier, Jérôme F; Corminbœuf, Clémence; Sherrill, C David
2015-08-07
We develop a simple methodology for the computation of symmetry-adapted perturbation theory (SAPT) interaction energy contributions for intramolecular noncovalent interactions. In this approach, the local occupied orbitals of the total Hartree-Fock (HF) wavefunction are used to partition the fully interacting system into three chemically identifiable units: the noncovalent fragments A and B and a covalent linker C. Once these units are identified, the noninteracting HF wavefunctions of the fragments A and B are separately optimized while embedded in the HF wavefunction of C, providing the dressed zeroth order wavefunctions for A and B in the presence of C. Standard two-body SAPT (particularly SAPT0) is then applied between the relaxed wavefunctions for A and B. This intramolecular SAPT procedure is found to be remarkably straightforward and efficient, as evidenced by example applications ranging from diols to hexaphenyl-ethane derivatives.
Li, Jimeng; Li, Ming; Zhang, Jinfeng
2017-08-01
Rolling bearings are the key components in the modern machinery, and tough operation environments often make them prone to failure. However, due to the influence of the transmission path and background noise, the useful feature information relevant to the bearing fault contained in the vibration signals is weak, which makes it difficult to identify the fault symptom of rolling bearings in time. Therefore, the paper proposes a novel weak signal detection method based on time-delayed feedback monostable stochastic resonance (TFMSR) system and adaptive minimum entropy deconvolution (MED) to realize the fault diagnosis of rolling bearings. The MED method is employed to preprocess the vibration signals, which can deconvolve the effect of transmission path and clarify the defect-induced impulses. And a modified power spectrum kurtosis (MPSK) index is constructed to realize the adaptive selection of filter length in the MED algorithm. By introducing the time-delayed feedback item in to an over-damped monostable system, the TFMSR method can effectively utilize the historical information of input signal to enhance the periodicity of SR output, which is beneficial to the detection of periodic signal. Furthermore, the influence of time delay and feedback intensity on the SR phenomenon is analyzed, and by selecting appropriate time delay, feedback intensity and re-scaling ratio with genetic algorithm, the SR can be produced to realize the resonance detection of weak signal. The combination of the adaptive MED (AMED) method and TFMSR method is conducive to extracting the feature information from strong background noise and realizing the fault diagnosis of rolling bearings. Finally, some experiments and engineering application are performed to evaluate the effectiveness of the proposed AMED-TFMSR method in comparison with a traditional bistable SR method.
Cognitive adaptation theory and quality of life in late-stage cancer patients.
Christianson, Heidi Fowell; Weis, Jo M; Fouad, Nadya A
2013-01-01
In this study, the question of whether using slightly illusionary, positive attributions of self, control, and meaning (e.g., cognitive adaptation theory), in the face of disconfirmatory evidence, facilitates quality of life in late-stage cancer patients was examined. Eighty late-stage cancer patients (Mean age = 59.7, SD = 12.5; 48.8% male, 51.2% female; varying cancer diagnoses) who recently failed or refused first line anti-neoplastic treatment completed questionnaires assessing meaning, control, self-esteem, and optimism, as well as physical and psychological quality of life. Findings suggest that greater self-esteem, control, and meaning predicted physical and psychological quality of life, with physical quality of life being influenced by control beliefs and psychological quality of life influenced by self-esteem. Optimism independently predicted physical quality of life and neither mediated nor moderated the relationship between cognitive adaptation and quality of life. Findings suggest that slightly positive, illusionary beliefs of self, control, and meaning predicted quality of life even in the presence of clear, disconfirmatory environmental evidence.
Item Response Theory Model Empat Parameter Logistik Pada Computerized Adaptive Test
Directory of Open Access Journals (Sweden)
Aslam Fatkhudin
2016-01-01
Full Text Available One of the computer-based testing is the Computerized Adaptive Test (CAT, which is a computer-based testing system where the items were given to the participants adapted to test the ability of the participants. Assessment methods are usually applied in CAT is Item Response Theory (IRT. IRT models are most commonly used today is the model 3 Parameter Logistic (3PL, which is about the discrimination, difficulty and guessing. However 3PL IRT models have not provided information more objectively test the ability of participants. The opinion of the test participants were tested items were also to be considered. In this study using CAT in combination with IRT model of 4PL. In this research, the development of CAT which uses about 4 parameters, namely the discrimination, difficulty, guessing and questionnaires. The questions used were about UAS 1 English subjects. Samples were taken from 30 students answer with the best value of the total 172 students spread across 6 classes to measure the parameter estimation problem. Further testing using CAT application 4PL IRT models compared to CAT 3PL IRT models. From research done shows that the CAT application combined with IRT models 4PL can measure the ability of the test taker shorter or faster and also opportunities participants correctly answered the test items was done tend to be better than the 3PL IRT models. Keywords: Ability; CAT; IRT; 3PL; 4PL; Probability; Test
Rajabi, Majid; Behzad, Mehdi
2014-04-01
In nonlinear acoustic regime, a body insonified by a sound field is known to experience a steady force that is called the acoustic radiation force (RF). This force is a second-order quantity of the velocity potential function of the ambient medium. Exploiting the sufficiency of linear solution representation of potential function in RF formulation, and following the classical resonance scattering theorem (RST) which suggests the scattered field as a superposition of the resonant field and a background (non-resonant) component, we will show that the radiation force is a composition of three components: background part, resonant part and their interaction. Due to the nonlinearity effects, each part contains the contribution of pure partial waves in addition to their mutual interaction. The numerical results propose the residue component (i.e., subtraction of the background component from the RF) as a good indicator of the contribution of circumferential surface waves in RF. Defining the modal series of radiation force function and its components, it will be shown that within each partial wave, the resonance contribution can be synthesized as the Breit-Wigner form for adequately none-close resonant frequencies. The proposed formulation may be helpful essentially due to its inherent value as a canonical subject in physical acoustics. Furthermore, it may make a tunnel through the circumferential resonance reducing effects on radiation forces. Copyright © 2013 Elsevier B.V. All rights reserved.
Huang, Xiaolei; Dong, Hui; Qiu, Yang; Li, Bo; Tao, Quan; Zhang, Yi; Krause, Hans-Joachim; Offenhäusser, Andreas; Xie, Xiaoming
2018-01-01
Power-line harmonic interference and fixed-frequency noise peaks may cause stripe-artifacts in ultra-low field (ULF) magnetic resonance imaging (MRI) in an unshielded environment and in a conductively shielded room. In this paper we describe an adaptive suppression method to eliminate these artifacts in MRI images. This technique utilizes spatial correlation of the interference from different positions, and is realized by subtracting the outputs of the reference channel(s) from those of the signal channel(s) using wavelet analysis and the least squares method. The adaptive suppression method is first implemented to remove the image artifacts in simulation. We then experimentally demonstrate the feasibility of this technique by adding three orthogonal superconducting quantum interference device (SQUID) magnetometers as reference channels to compensate the output of one 2nd-order gradiometer. The experimental results show great improvement in the imaging quality in both 1D and 2D MRI images at two common imaging frequencies, 1.3 kHz and 4.8 kHz. At both frequencies, the effective compensation bandwidth is as high as 2 kHz. Furthermore, we examine the longitudinal relaxation times of the same sample before and after compensation, and show that the MRI properties of the sample did not change after applying adaptive suppression. This technique can effectively increase the imaging bandwidth and be applied to ULF MRI detected by either SQUIDs or Faraday coil in both an unshielded environment and a conductively shielded room.
Zhang, Xin; Miao, Qiang; Liu, Zhiwen; He, Zhengjia
2017-11-01
Stochastic resonance (SR) is widely used as an enhanced signal detection method in machinery fault diagnosis. However, the system parameters have significant effects on the output results, which makes it difficult for SR method to achieve satisfactory analysis results. To solve this problem and improve the performance of SR method, this paper proposes an adaptive SR method based on grey wolf optimizer (GWO) algorithm for machinery fault diagnosis. Firstly, the SR system parameters are optimized by the GWO algorithm using a redefined signal-to-noise ratio (SNR) as optimization objective function. Then, the optimal SR output matching the input signal can be adaptively obtained using the optimized parameters. The proposed method is validated on a simulated signal detection and a rolling element bearing test bench, and then applied to the gear fault diagnosis of electric locomotive. Compared with the conventional fixed-parameter SR method, the adaptive SR method based on genetic algorithm (GA-SR) as well as the well-known fast kurtogram method, the proposed method can achieve a greater accuracy. The results indicated that the proposed method has great practical values in engineering. Copyright © 2017. Published by Elsevier Ltd.
Resonance scattering by auroral N2+: steady state theory and observations from Svalbard
Directory of Open Access Journals (Sweden)
O. Jokiaho
2009-09-01
Full Text Available Studies of auroral energy input at high latitudes often depend on observations of emissions from the first negative band of ionised nitrogen. However, these emissions are affected by solar resonance scattering, which makes photometric and spectrographic measurements difficult to interpret. This work is a statistical study from Longyearbyen, Svalbard, Norway, during the solar minimum between January and March 2007, providing a good coverage in shadow height position and precipitation conditions. The High Throughput Imaging Echelle Spectrograph (HiTIES measured three bands of N2+ 1N (0,1, (1,2 and (2,3, and one N2 2P band (0,3 in the magnetic zenith. The brightness ratios of the N2+ bands are compared with a theoretical treatment with excellent results. Balance equations for all important vibrational levels of the three lowest electronic states of the N2+ molecule are solved for steady-state, and the results combined with ion chemistry modelling. Brightnesses of the (0,1, (1,2 and (2,3 bands of N2+ 1N are calculated for a range of auroral electron energies, and different values of shadow heights. It is shown that in sunlit aurora, the brightness of the (0,1 band is enhanced, with the scattered contribution increasing with decreasing energy of precipitation (10-fold enhancements for energies of 100 eV. The higher vibrational bands are enhanced even more significantly. In sunlit aurora the observed 1N (1,2/(0,1 and (2,3/(0,1 ratios increase as a function of decreasing precipitation energy, as predicted by theory. In non-sunlit aurora the N2+ species have a constant proportionality to neutral N2. The ratio of 2P(0,3/1N(0,1 in the morning hours shows a pronounced decrease, indicating enhancement of N2+ 1N emission. Finally we study the relationship of all emissions and their ratios to rotational temperatures. A clear effect is observed on rotational development of the bands. It is possible that greatly enhanced rotational temperatures may be a
Universal dynamics of complex adaptive systems: Gauge theory of things alive
International Nuclear Information System (INIS)
Mack, G.
1994-04-01
A universal dynamics of objects and their relations - a kind of ''universal chemistry'' - is discussed which satisfies general principles of locality and relativity. Einsteins theory of gravitation and the gauge theory of elementary particles are prototypes, but complex adaptive systems - anything that is alive in the widest sense - fall under the same paradigma. Frustration and gauge symmetry arise naturally in this context. Besides a nondissipative deterministic dynamics, which is thought to operate at a fundamental levle, a Thermo-Dynamics in sense of Prigogine is introduced by adding a diffusion process. It introduces irreversibility and entropy production. It equilibrates the chaotic local model of the time development (only) and is designed to be undetectable under continued observation with given finite measuring accuracy. Compositeness and the development of structure can be described in this framework. The existence of a critical equilibrium state may be postulated which is invariant under the dynamics. But it is usually not reached in a finite time from a given starting configuration, because local dynamics suffers from critical slowing down, especially in the presence of frustration. (orig.)
Adapting evidence-based interventions using a common theory, practices, and principles.
Rotheram-Borus, Mary Jane; Swendeman, Dallas; Becker, Kimberly D
2014-01-01
Hundreds of validated evidence-based intervention programs (EBIP) aim to improve families' well-being; however, most are not broadly adopted. As an alternative diffusion strategy, we created wellness centers to reach families' everyday lives with a prevention framework. At two wellness centers, one in a middle-class neighborhood and one in a low-income neighborhood, popular local activity leaders (instructors of martial arts, yoga, sports, music, dancing, Zumba), and motivated parents were trained to be Family Mentors. Trainings focused on a framework that taught synthesized, foundational prevention science theory, practice elements, and principles, applied to specific content areas (parenting, social skills, and obesity). Family Mentors were then allowed to adapt scripts and activities based on their cultural experiences but were closely monitored and supervised over time. The framework was implemented in a range of activities (summer camps, coaching) aimed at improving social, emotional, and behavioral outcomes. Successes and challenges are discussed for (a) engaging parents and communities; (b) identifying and training Family Mentors to promote children and families' well-being; and (c) gathering data for supervision, outcome evaluation, and continuous quality improvement. To broadly diffuse prevention to families, far more experimentation is needed with alternative and engaging implementation strategies that are enhanced with knowledge harvested from researchers' past 30 years of experience creating EBIP. One strategy is to train local parents and popular activity leaders in applying robust prevention science theory, common practice elements, and principles of EBIP. More systematic evaluation of such innovations is needed.
Pla, Frederic G. (Inventor); Rajiyah, Harindra (Inventor); Renshaw, Anthony A. (Inventor); Hedeen, Robert A. (Inventor)
1995-01-01
A noise source for an aircraft engine active noise cancellation system in which the resonant frequency of a noise radiating element is tuned to permit noise cancellation over a wide range of frequencies. The resonant frequency of the noise radiating element is tuned by an expandable ring embedded in the noise radiating element. Excitation of the ring causes expansion or contraction of the ring, thereby varying the stress in the noise radiating element. The ring is actuated by a controller which receives input of a feedback signal proportional to displacement of the noise radiating element and a signal corresponding to the blade passage frequency of the engine's fan. In response, the controller determines a control signal which is sent to the ring, causing the ring to expand or contract. Instead of a single ring embedded in the noise radiating panel, a first expandable ring can be bonded to one side of the noise radiating element, and a second expandable ring can be bonded to the other side.
Silva, P H R; Spedo, C T; Barreira, A A; Leoni, R F
2018-02-01
The Symbol Digit Modalities Test (SDMT) is widely used for cognitive evaluation of information processing speed (IPS), required in many cognitive operations. Despite being unspecific for different neurological disorders, it is sensitive to assess impaired performance related to stroke, Parkinson's disease, traumatic brain injury, and multiple sclerosis. However, in addition to evaluate the presence and severity of IPS impairment, it is of interest to determine the localization and integration of brain regions responsible for the functions assessed by the SDMT. To review the studies that adapted the SDMT to the magnetic resonance environment and obtain the brain areas associated with the performance of the task in healthy subjects with a meta-analysis. A systematic review was performed using ten studies published between 1990 and 2017, and selected from four databases. All studies included participants of both genders and age between 18 and 50 years, used Functional Magnetic Resonance Imaging (fMRI) and SDMT adaptation and reported brain regions associated with the task. Six of them also reported the region coordinates in a standard space, so they were included in a meta-analysis. Activation Likelihood Estimation algorithm, with significance for p < 0.05 corrected for multiple comparisons, was used to identify areas that are robustly related to the performance of the SDMT. The areas predominantly reported in the studies of our meta-analysis were regions of the frontoparietal attentional network and occipital cortex, as well as cuneus, precuneus, and cerebellum. Individually all regions that survived the statistical threshold are consistent with what is expected after reviewing prospective studies. The present study allowed the identification of brain areas activated during the performance of the SDMT in healthy subjects, and therefore it will help understanding the differences in brain activation by this task in clinical populations. Moreover, it may guide future
Broom, Donald M
2006-01-01
The term adaptation is used in biology in three different ways. It may refer to changes which occur at the cell and organ level, or at the individual level, or at the level of gene action and evolutionary processes. Adaptation by cells, especially nerve cells helps in: communication within the body, the distinguishing of stimuli, the avoidance of overload and the conservation of energy. The time course and complexity of these mechanisms varies. Adaptive characters of organisms, including adaptive behaviours, increase fitness so this adaptation is evolutionary. The major part of this paper concerns adaptation by individuals and its relationships to welfare. In complex animals, feed forward control is widely used. Individuals predict problems and adapt by acting before the environmental effect is substantial. Much of adaptation involves brain control and animals have a set of needs, located in the brain and acting largely via motivational mechanisms, to regulate life. Needs may be for resources but are also for actions and stimuli which are part of the mechanism which has evolved to obtain the resources. Hence pigs do not just need food but need to be able to carry out actions like rooting in earth or manipulating materials which are part of foraging behaviour. The welfare of an individual is its state as regards its attempts to cope with its environment. This state includes various adaptive mechanisms including feelings and those which cope with disease. The part of welfare which is concerned with coping with pathology is health. Disease, which implies some significant effect of pathology, always results in poor welfare. Welfare varies over a range from very good, when adaptation is effective and there are feelings of pleasure or contentment, to very poor. A key point concerning the concept of individual adaptation in relation to welfare is that welfare may be good or poor while adaptation is occurring. Some adaptation is very easy and energetically cheap and
International Nuclear Information System (INIS)
Son, Minho; Urbano, Alfredo
2016-01-01
We interpret the recently observed excess in the diphoton invariant mass as a new spin-0 resonant particle. On theoretical grounds, an interesting question is whether this new scalar resonance belongs to a strongly coupled sector or a well-defined weakly coupled theory. A possible UV-completion that has been widely considered in literature is based on the existence of new vector-like fermions whose loop contributions — Yukawa-coupled to the new resonance — explain the observed signal rate. The large total width preliminarily suggested by data seems to favor a large Yukawa coupling, at the border of a healthy perturbative definition. This potential problem can be fixed by introducing multiple vector-like fermions or large electric charges, bringing back the theory to a weakly coupled regime. However, this solution risks to be only a low-energy mirage: large multiplicity or electric charge can dangerously reintroduce the strong regime by modifying the renormalization group running of the dimensionless couplings. This issue is also tightly related to the (in)stability of the scalar potential. First, we study — in the theoretical setup described above — the parametric behavior of the diphoton signal rate, total width, and one-loop β functions. Then, we numerically solve the renormalization group equations, taking into account the observed diphoton signal rate and total width, to investigate the fate of the weakly coupled theory. We find that — with the only exception of few fine-tuned directions — weakly coupled interpretations of the excess are brought back to a strongly coupled regime if the running is taken into account.
Implications of naturalness in effective field theory on the masses of resonances
International Nuclear Information System (INIS)
Dugan, M.J.; Golden, M.
1993-01-01
Many years ago Weinberg formulated a definition of ''naturalness'' for effective theories: if an effective theory is to make sense, coefficients must not change too much when the cutoff scale is changed by a factor of order 1. As an example we consider simple field theories in which an O(N) symmetry spontaneously breaks to O(N-1). We show that in these theories Weinberg's criterion for a natural effective theory may be applied directly to the S matrix; it implies that the scale of new physics, beyond the Goldstone bosons, may not be too large: there is always a particle or a cut of mass below or about 4πf/ √N . We discuss the range of convergence of the expansion of the chiral Lagrangian. It appears to be impossible to construct an underlying theory of the type considered here that fails to satisfy Weinberg's criterion
CSIR Research Space (South Africa)
Görür, OC
2017-03-01
Full Text Available We propose an architecture that integrates Theory of Mind into a robot’s decision-making to infer a human’s intention and adapt to it. The architecture implements humanrobot collaborative decision-making for a robot incorporating human variability...
The puzzle of partial migration: Adaptive dynamics and evolutionary game theory perspectives.
De Leenheer, Patrick; Mohapatra, Anushaya; Ohms, Haley A; Lytle, David A; Cushing, J M
2017-01-07
We consider the phenomenon of partial migration which is exhibited by populations in which some individuals migrate between habitats during their lifetime, but others do not. First, using an adaptive dynamics approach, we show that partial migration can be explained on the basis of negative density dependence in the per capita fertilities alone, provided that this density dependence is attenuated for increasing abundances of the subtypes that make up the population. We present an exact formula for the optimal proportion of migrants which is expressed in terms of the vital rates of migrant and non-migrant subtypes only. We show that this allocation strategy is both an evolutionary stable strategy (ESS) as well as a convergence stable strategy (CSS). To establish the former, we generalize the classical notion of an ESS because it is based on invasion exponents obtained from linearization arguments, which fail to capture the stabilizing effects of the nonlinear density dependence. These results clarify precisely when the notion of a "weak ESS", as proposed in Lundberg (2013) for a related model, is a genuine ESS. Secondly, we use an evolutionary game theory approach, and confirm, once again, that partial migration can be attributed to negative density dependence alone. In this context, the result holds even when density dependence is not attenuated. In this case, the optimal allocation strategy towards migrants is the same as the ESS stemming from the analysis based on the adaptive dynamics. The key feature of the population models considered here is that they are monotone dynamical systems, which enables a rather comprehensive mathematical analysis. Copyright © 2016 Elsevier Ltd. All rights reserved.
Adaptation of Organisms by Resonance of RNA Transcription with the Cellular Redox Cycle
Stolc, Viktor
2012-01-01
Sequence variation in organisms differs across the genome and the majority of mutations are caused by oxidation, yet its origin is not fully understood. It has also been shown that the reduction-oxidation reaction cycle is the fundamental biochemical cycle that coordinates the timing of all biochemical processes in that cell, including energy production, DNA replication, and RNA transcription. It is shown that the temporal resonance of transcriptome biosynthesis with the oscillating binary state of the reduction-oxidation reaction cycle serves as a basis for non-random sequence variation at specific genome-wide coordinates that change faster than by accumulation of chance mutations. This work demonstrates evidence for a universal, persistent and iterative feedback mechanism between the environment and heredity, whereby acquired variation between cell divisions can outweigh inherited variation.
AUS module MIRANDA - a data preparation code based on multiregion resonance theory
International Nuclear Information System (INIS)
Robinson, G.S.
1977-07-01
MIRANDA is a data preparation module of the AUS reactor neutronics scheme and is used to prepare multigroup cross-section data which are pertinent to a particular reactor system from a general purpose multigroup library of cross sections. The cross-section library has been prepared from ENDF/B and includes temperature dependent data and resonance cross sections represented by subgroup parameters. The MIRANDA module includes a multiregion resonance calculation in slab, cylinder or cluster geometry, a homogeneous Bsub(L) flux solution, and a group condensation facility. Interaction with other AUS modules, particularly for burnup calculations, is provided. (Author)
Microscopic Many-Body Theory of Atomic Bose Gases near a Feshbach Resonance
Duine, R.A.; Stoof, H.T.C.
2003-01-01
A Feshbach resonance in the s-wave scattering length occurs if the energy of the two atoms in the incoming open channel is close to the energy of a bound state in a coupled closed channel. Starting from the microscopic Hamiltonian that describes this situation, we derive the
International Nuclear Information System (INIS)
Yablonovitch, E.
1979-09-01
New results are reported on the angular and energy spectrum of resonantly accelerated electrons from a shock front as measured by a miniature β-ray spectrometer. We have devised a multichannel electron collector based on printed circuit board technology. It has been multiplexed into a fast oscilloscope to provide a complete absolute spectrum on a single laser shot
Reduction of fan noise bymeans of (circular) side-resonators; theory and experiment
Nijhof, M.J.J.; Wijnant, Ysbrand H.; de Boer, Andries; Beltman, W.M.
2004-01-01
One of the main noise sources in computers are the cooling fans. An important aspect of the noise they generate is tonal noise produced at the rotational frequency of the fan, the blade passing frequency (BPF), and its higher harmonics. Previous research pointed out that so-called side resonators
CR-Calculus and adaptive array theory applied to MIMO random vibration control tests
Musella, U.; Manzato, S.; Peeters, B.; Guillaume, P.
2016-09-01
Performing Multiple-Input Multiple-Output (MIMO) tests to reproduce the vibration environment in a user-defined number of control points of a unit under test is necessary in applications where a realistic environment replication has to be achieved. MIMO tests require vibration control strategies to calculate the required drive signal vector that gives an acceptable replication of the target. This target is a (complex) vector with magnitude and phase information at the control points for MIMO Sine Control tests while in MIMO Random Control tests, in the most general case, the target is a complete spectral density matrix. The idea behind this work is to tailor a MIMO random vibration control approach that can be generalized to other MIMO tests, e.g. MIMO Sine and MIMO Time Waveform Replication. In this work the approach is to use gradient-based procedures over the complex space, applying the so called CR-Calculus and the adaptive array theory. With this approach it is possible to better control the process performances allowing the step-by-step Jacobian Matrix update. The theoretical bases behind the work are followed by an application of the developed method to a two-exciter two-axis system and by performance comparisons with standard methods.
Effective theory for neutral resonances and a statistical dissection of the ATLAS diboson excess
Energy Technology Data Exchange (ETDEWEB)
Fichet, Sylvain; Gersdorff, Gero von [ICTP South American Institute for Fundamental Research, Instituto de Fisica Teorica,Rua Dr. Bento Teobaldo Ferraz, 271, São Paulo, São Paulo State University (Brazil)
2015-12-15
We classify the complete set of dimension-5 operators relevant for the resonant production of a singlet of spin 0 or 2 linearly coupled to the Standard Model (SM). We compute the decay width of such states as a function of the effective couplings, and provide the matching to various well-motivated New Physics scenarios. We then investigate the possibility that one of these neutral resonances be at the origin of the excess in diboson production recently reported by the ATLAS collaboration. We perform a shape analysis of the excess under full consideration of the systematic uncertainties to extract the width Γ{sub tot} of the hypothetical resonance, finding it to be in the range 26 GeV <Γ{sub tot}< 144 GeV at 95% C.L. We then point out that the three overlapping selections WW, WZ, ZZ reported by ATLAS follow a joint trivariate Poisson distribution, which opens the possibility of a thorough likelihood analysis of the event rates. The background systematic uncertainties are also included in our analysis. We show that the data do not require W Z production and could thus in principle be explained by neutral resonances. We then use both the information on the width and the cross section, which prove to be highly complementary, to test the effective Lagrangians of singlet resonances. Regarding specific models, we find that neither scalars coupled via the Higgs-portal nor the Randall-Sundrum (RS) radion can explain the ATLAS anomaly. The RS graviton with all matter on the infrared (IR) brane can in principle fit the observed excess, while the RS model with matter propagating in the bulk requires the presence of IR brane kinetic terms for the gauge fields.
International Development Research Centre (IDRC) Digital Library (Canada)
. Dar es Salaam. Durban. Bloemfontein. Antananarivo. Cape Town. Ifrane ... program strategy. A number of CCAA-supported projects have relevance to other important adaptation-related themes such as disaster preparedness and climate.
International Nuclear Information System (INIS)
Shore, B.W.
1977-01-01
The long-time average of level populations in a coherently-excited anharmonic sequence of energy levels (e.g., an anharmonic oscillator) exhibits sharp resonances as a function of laser frequency. For simple linearly-increasing anharmonicity, each resonance is a superposition of various multiphoton resonances (e.g., a superposition of 3, 5, 7, . . . photon resonances), each having its own characteristic width predictable from perturbation theory
The Physics and Mathematical Theory of Nano-Scaled Ring Resonators and Loop Antennas
McKinley, A. F.
2014-01-01
This thesis is based on the realisation that no analytical theory of loop antennas and rings exists that is at once applicable to the Radio Frequency (RF), Micro-wave (MW), TeraHertz (THz), Infra-red (IR), and Optical (OR) regions. Nor is there any Electrical Engineering circuit model, rigorously developed from the results of that theory, that generates results which match numerical simulations and experimental work in the literature across all of these regimes. This thesis fills that gap. Ma...
Introduction to theory and analysis of resolved (and unresolved) neutron resonances via SAMMY
International Nuclear Information System (INIS)
Larson, N.M.
1998-07-01
Neutron cross-section data are important for two distinct purposes: first, they provide insight into the nature of matter, thus assisting in the understanding of fundamental physics; second, they are needed for practical applications (e.g., for calculating when and how a reactor will become critical, or how much shielding is needed for storage of nuclear materials, and for medical applications). Neutron cross section data in the resolved-resonance region are generally obtained by time-of-flight experiments, which must be carefully analyzed if they are to be properly understood and utilized. In this paper, important features of the analysis process are discussed, with emphasis on the particular technique used in the analysis code SAMMY. Other features of the code are also described; these include such topics as calculation of group cross sections (including covariance matrices), generation and fitting of integral quantities, and extensions into the unresolved-resonance region and higher-energy regions
Introduction to the theory and analysis of resolved (and unresolved) neutron resonances via SAMMY
Energy Technology Data Exchange (ETDEWEB)
Larson, N.M.
1998-02-01
Neutron cross-section data are important for two distinct purposes: First, they provide insight into the nature of matter, thus assisting in the understanding of fundamental physics. Second, they are needed for practical applications (e.g., for calculating when and how a reactor will become critical, or how much shielding is needed for storage of nuclear materials, and for medical applications). Neutron cross section data in the resolved-resonance region are generally obtained by time-of-flight experiments, which must be carefully analyzed if they are to be properly understood and utilized. In this paper, important features of the analysis process are discussed, with emphasis on the particular techniques used in the analysis code SAMMY. Other features of the code are also described; these include such topics as calculation of group cross sections (including covariance matrices), generation and fitting of integral quantities, and extensions into the unresolved-resonance region and higher energy regions.
Introduction to the Theory and Analysis of Resolved (and Unresolved) Neutron Resonances via SAMMY
Energy Technology Data Exchange (ETDEWEB)
Larson, N.
2000-03-13
Neutron cross-section data are important for two purposes: First, they provide insight into the nature of matter, increasing our understanding of fundamental physics. Second, they are needed for practical applications (e.g., for calculating when and how a reactor will become critical, or how much shielding is needed for storage of nuclear materials, or for medical applications). Neutron cross section data in the resolved-resonance region are generally obtained by time-of-flight experiments, which must be carefully analyzed if they are to be properly understood and utilized. In this report, important features of the analysis process are discussed, with emphasis on the particular techniques used in the analysis code SAMMY. Other features of the code are also described; these include such topics as calculation of group cross sections (including covariance matrices), generation and fitting of integral quantities, and extensions into the unresolved-resonance region and higher-energy regions.
Introduction to theory and analysis of resolved (and unresolved) neutron resonances via SAMMY
Energy Technology Data Exchange (ETDEWEB)
Larson, N.M.
1998-07-01
Neutron cross-section data are important for two distinct purposes: first, they provide insight into the nature of matter, thus assisting in the understanding of fundamental physics; second, they are needed for practical applications (e.g., for calculating when and how a reactor will become critical, or how much shielding is needed for storage of nuclear materials, and for medical applications). Neutron cross section data in the resolved-resonance region are generally obtained by time-of-flight experiments, which must be carefully analyzed if they are to be properly understood and utilized. In this paper, important features of the analysis process are discussed, with emphasis on the particular technique used in the analysis code SAMMY. Other features of the code are also described; these include such topics as calculation of group cross sections (including covariance matrices), generation and fitting of integral quantities, and extensions into the unresolved-resonance region and higher-energy regions.
Theory and applications of maps on SO(3) in nuclear magnetic resonance
International Nuclear Information System (INIS)
Cho, H.M.
1987-02-01
Theoretical approaches and experimental work in the design of multiple pulse sequences in Nuclear Magnetic Resonance (NMR) are the subjects of this dissertation. Sequences of discrete pulses which reproduce the nominal effect of single pulses, but over substantially broader, narrower, or more selective ranges of transition frequencies, radiofrequency field amplitudes, and spin-spin couplings than the single pulses they replace, are developed and demonstrated. 107 refs., 86 figs., 6 tabs
DEFF Research Database (Denmark)
Jørgensen, E.; Koshelets, V. P.; Monaco, Roberto
1982-01-01
The radiation emission from long and narrow Josephson tunnel junctions dc-current biased on zero-field steps has been ascribed to resonant motion of fluxons on the transmission line. Within this dynamic model a theoretical expression for the radiation linewidth is derived from a full statistical ...... treatment of thermal fluctuations in the fluxon velocity. The result appears to be very general and is corroborated by experimental determination of linewidth and frequency of radiation emitted from overlap Nb-I-Pb junctions....
Tiwari, Vivek; Peters, William K; Jonas, David M
2017-10-21
Non-adiabatic vibrational-electronic resonance in the excited electronic states of natural photosynthetic antennas drastically alters the adiabatic framework, in which electronic energy transfer has been conventionally studied, and suggests the possibility of exploiting non-adiabatic dynamics for directed energy transfer. Here, a generalized dimer model incorporates asymmetries between pigments, coupling to the environment, and the doubly excited state relevant for nonlinear spectroscopy. For this generalized dimer model, the vibrational tuning vector that drives energy transfer is derived and connected to decoherence between singly excited states. A correlation vector is connected to decoherence between the ground state and the doubly excited state. Optical decoherence between the ground and singly excited states involves linear combinations of the correlation and tuning vectors. Excitonic coupling modifies the tuning vector. The correlation and tuning vectors are not always orthogonal, and both can be asymmetric under pigment exchange, which affects energy transfer. For equal pigment vibrational frequencies, the nonadiabatic tuning vector becomes an anti-correlated delocalized linear combination of intramolecular vibrations of the two pigments, and the nonadiabatic energy transfer dynamics become separable. With exchange symmetry, the correlation and tuning vectors become delocalized intramolecular vibrations that are symmetric and antisymmetric under pigment exchange. Diabatic criteria for vibrational-excitonic resonance demonstrate that anti-correlated vibrations increase the range and speed of vibronically resonant energy transfer (the Golden Rule rate is a factor of 2 faster). A partial trace analysis shows that vibronic decoherence for a vibrational-excitonic resonance between two excitons is slower than their purely excitonic decoherence.
Siegel, Edward
2011-10-01
Numbers: primality/indivisibility/non-factorization versus compositeness/divisibility /factor-ization, often in tandem but not always, provocatively close analogy to nuclear-physics: (2 + 1)=(fusion)=3; (3+1)=(fission)=4[=2 × 2]; (4+1)=(fusion)=5; (5 +1)=(fission)=6[=2 × 3]; (6 + 1)=(fusion)=7; (7+1)=(fission)=8[= 2 × 4 = 2 × 2 × 2]; (8 + 1) =(non: fission nor fusion)= 9[=3 × 3]; then ONLY composites' Islands of fusion-INstability: 8, 9, 10; then 14, 15, 16,... Could inter-digit Feshbach-resonances exist??? Applications to: quantum-information/computing non-Shore factorization, millennium-problem Riemann-hypotheses proof as Goodkin BEC intersection with graph-theory ``short-cut'' method: Rayleigh(1870)-Polya(1922)-``Anderson'' (1958)-localization, Goldbach-conjecture, financial auditing/accounting as quantum-statistical-physics;... abound!!!
Directory of Open Access Journals (Sweden)
Matthias C. Krantz
2013-05-01
Full Text Available Resonant bending-mode magnetoelectric (ME coefficients of magnetostrictive-piezoelectric multilayer cantilevers are calculated analytically using a model developed for arbitrary multilayers on a substrate. Without quality factor effects the ME coefficient maxima in the four-dimensional parameter space of layer numbers, layer sequences, piezoelectric volume fractions, and substrate thicknesses are found to be essentially constant for nonzero substrate thickness. Global maxima occur for bilayers without substrates. Vanishing magnetoelectric response regions result from voltage cancellation in piezoelectric layers or absence of bending-mode excitation. They are determined by the neutral plane position in the multilayer stack. With Q-factor effects dominated by viscous air damping ME coefficients strongly increase with cantilever thickness primarily due to increasing resonance frequencies. The results yield a layer specific prediction of ME coefficients, resonance frequencies, and Q-factors in arbitrary multilayers and thus distinction of linear-coupling and Q-factor effects from exchange interaction, interface, or nonlinear ME effects.
Krommes, John A.
2015-12-01
> In honour of the 50th anniversary of the influential review/monograph on plasma turbulence by B. B. Kadomtsev as well as the seminal works of T. H. Dupree and J. Weinstock on resonance-broadening theory, an introductory tutorial is given about some highlights of the statistical-dynamical description of turbulent plasmas and fluids, including the ideas of nonlinear incoherent noise, coherent damping, and self-consistent dielectric response. The statistical closure problem is introduced. Incoherent noise and coherent damping are illustrated with a solvable model of passive advection. Self-consistency introduces turbulent polarization effects that are described by the dielectric function . Dupree's method of using to estimate the saturation level of turbulence is described; then it is explained why a more complete theory that includes nonlinear noise is required. The general theory is best formulated in terms of Dyson equations for the covariance and an infinitesimal response function , which subsumes . An important example is the direct-interaction approximation (DIA). It is shown how to use Novikov's theorem to develop an -space approach to the DIA that is complementary to the original -space approach of Kraichnan. A dielectric function is defined for arbitrary quadratically nonlinear systems, including the Navier-Stokes equation, and an algorithm for determining the form of in the DIA is sketched. The independent insights of Kadomtsev and Kraichnan about the problem of the DIA with random Galilean invariance are described. The mixing-length formula for drift-wave saturation is discussed in the context of closures that include nonlinear noise (shielded by ). The role of in the calculation of the symmetry-breaking (zonostrophic) instability of homogeneous turbulence to the generation of inhomogeneous mean flows is addressed. The second-order cumulant expansion and the stochastic structural stability theory are also discussed in that context. Various historical
Girard, Corentin; Rinaudo, Jean-Daniel; Pulido-Velazquez, Manuel
2016-10-01
The adaptation of water resource systems to the potential impacts of climate change requires mixed portfolios of supply and demand adaptation measures. The issue is not only to select efficient, robust, and flexible adaptation portfolios but also to find equitable strategies of cost allocation among the stakeholders. Our work addresses such cost allocation problems by applying two different theoretical approaches: social justice and cooperative game theory in a real case study. First of all, a cost-effective portfolio of adaptation measures at the basin scale is selected using a least-cost optimization model. Cost allocation solutions are then defined based on economic rationality concepts from cooperative game theory (the Core). Second, interviews are conducted to characterize stakeholders' perceptions of social justice principles associated with the definition of alternatives cost allocation rules. The comparison of the cost allocation scenarios leads to contrasted insights in order to inform the decision-making process at the river basin scale and potentially reap the efficiency gains from cooperation in the design of river basin adaptation portfolios.
Bargatze, L. F.
2015-12-01
Active Data Archive Product Tracking (ADAPT) is a collection of software routines that permits one to generate XML metadata files to describe and register data products in support of the NASA Heliophysics Virtual Observatory VxO effort. ADAPT is also a philosophy. The ADAPT concept is to use any and all available metadata associated with scientific data to produce XML metadata descriptions in a consistent, uniform, and organized fashion to provide blanket access to the full complement of data stored on a targeted data server. In this poster, we present an application of ADAPT to describe all of the data products that are stored by using the Common Data File (CDF) format served out by the CDAWEB and SPDF data servers hosted at the NASA Goddard Space Flight Center. These data servers are the primary repositories for NASA Heliophysics data. For this purpose, the ADAPT routines have been used to generate data resource descriptions by using an XML schema named Space Physics Archive, Search, and Extract (SPASE). SPASE is the designated standard for documenting Heliophysics data products, as adopted by the Heliophysics Data and Model Consortium. The set of SPASE XML resource descriptions produced by ADAPT includes high-level descriptions of numerical data products, display data products, or catalogs and also includes low-level "Granule" descriptions. A SPASE Granule is effectively a universal access metadata resource; a Granule associates an individual data file (e.g. a CDF file) with a "parent" high-level data resource description, assigns a resource identifier to the file, and lists the corresponding assess URL(s). The CDAWEB and SPDF file systems were queried to provide the input required by the ADAPT software to create an initial set of SPASE metadata resource descriptions. Then, the CDAWEB and SPDF data repositories were queried subsequently on a nightly basis and the CDF file lists were checked for any changes such as the occurrence of new, modified, or deleted
Kahle, L R; Kulka, R A; Klingel, D M
1980-09-01
This article reports the results of a study that annually monitored the self-esteem and interpersonal problems of over 100 boys during their sophomore, junior, and senior years of high school. Cross-lagged panel correlation differences show that low self-esteem leads to interpersonal problems in all three time lags when multiple interpersonal problems constitute the dependent variable but not when single interpersonal problem criteria constitute the dependent variable. These results are interpreted as supporting social-adaptation theory rather than self-perception theory. Implications for the conceptual status of personality variables as causal antecedents and for the assessment of individual differences are discussed.
International Nuclear Information System (INIS)
Stoitsov, M.V.; Ring, P.; Sharma, M.M.
1994-01-01
The breathing-mode giant monopole resonance (GMR) is studied within the framework of the relativistic mean-field theory (RMF) using the generator coordinate method (GCM). The constrained incompressibility and the excitation energy of isoscalar giant monopole states are obtained for finite nuclei with various sets of Lagrangian parameters. A comparison is made with the results of nonrelativistic constrained Skyrme Hartree-Fock (HF) calculations and with those from Skyrme random phase approximation (RPA) calculations. In the RMF theory the GCM calculations give a transition density for the breathing mode, which greatly resembles that obtained from the Skyrme HF+RPA approach and also that from the scaling mode of the GMA. From the systematic study of the breathing-mode as a function of the incompressibility in GCM, it is shown that the GCM succeeds in describing the GMR energies in nuclei and that the empirical breathing-mode energies of heavy nuclei can be reproduced by forces with an incompressibility close to K=300 MeV in the RMF theory
Theory of resonant donor-impurity magnetopolaron in semiconductor quantum wells
International Nuclear Information System (INIS)
Osorio, F.A.P.; Maialle, M.Z.; Hipolito, O.
1989-11-01
We report for the first time a theoretical calculation for the resonant donor impurity magnetopolaron in GaAs-GA 1-x Al x As quantum-well structures. The intra donor 1s → 2p, transition frequencies are calculated as a function of the magnetic field, by taking into account the polaron effects and nonparabolicity of the conduction band. We found a pinning behaviour due to interaction with LO phonons as suggested by the experimentalists. Our results for the peak positions of those transitions are in very good agreement with recent experimental data. (author). 18 refs, 1 fig
The parametric resonance features for theory of energy transfer in dusty plasma
Semyonov, V. P.; Timofeev, A. V.
2015-11-01
One of the mechanisms of energy transfer between degrees of freedom of dusty plasma system can be described by equations similar to Mathieu equation with account of stochastic forces. Such equation is studied by analytical approach. The solutions for higher order of accuracy are obtained. The method for numerical solution and resonance zone detection is proposed. The solution for the extended Mathieu equation is obtained for wide range of parameter values. The results of numerical solution are compared with analytical solutions of different order and known analytical results for Mathieu equation.
Topology in SU(2) lattice gauge theory and parallelization of functional magnetic resonance imaging
Energy Technology Data Exchange (ETDEWEB)
Solbrig, Stefan
2008-07-01
In this thesis, I discuss topological properties of quenched SU(2) lattice gauge fields. In particular, clusters of topological charge density exhibit a power-law. The exponent of that power-law can be used to validate models for lattice gauge fields. Instead of working with fixed cutoffs of the topological charge density, using the notion of a ''watermark'' is more convenient. Furthermore, I discuss how a parallel computer, originally designed for lattice gauge field simulations, can be used for functional magnetic resonance imaging. Multi parameter fits can be parallelized to achieve almost real-time evaluation of fMRI data. (orig.)
Topology in SU(2) lattice gauge theory and parallelization of functional magnetic resonance imaging
International Nuclear Information System (INIS)
Solbrig, Stefan
2008-01-01
In this thesis, I discuss topological properties of quenched SU(2) lattice gauge fields. In particular, clusters of topological charge density exhibit a power-law. The exponent of that power-law can be used to validate models for lattice gauge fields. Instead of working with fixed cutoffs of the topological charge density, using the notion of a ''watermark'' is more convenient. Furthermore, I discuss how a parallel computer, originally designed for lattice gauge field simulations, can be used for functional magnetic resonance imaging. Multi parameter fits can be parallelized to achieve almost real-time evaluation of fMRI data. (orig.)
International Nuclear Information System (INIS)
Li Tao
2001-01-01
A model with interlayer pairing is proposed to explain the sinusoidal modulation of the resonant neutron scattering in high-temperature superconductors. It is found that the interlayer pairing has s-wave symmetry in the CuO 2 plane and has comparable magnitude with the d-wave intralayer pairing. It is also found that the interlayer pairing mainly affects momentum close to the hot spots on the Fermi surface while its effect on the gap nodes is negligible. It is pointed out that these characteristics of the interlayer pairing can be understood in a model in which the superconducting pairing originates from the exchange of the antiferromagnetic spin fluctuation
Gluck, M.A.; Myers, C.E; Meeter, M.
2005-01-01
Computational models of the hippocampal region link psychological theories of associative learning with their underlying physiological and anatomical substrates. Our approach to theory development began with a broad description of the computations that depend on the hippocampal region in classical
DEFF Research Database (Denmark)
Bruus, Henrik
2009-01-01
fields, which are directly related to the acoustic radiation force on single particles and to the acoustic streaming of the liquid. For the radiation pressure effects, there is good agreement between theory and simulation, while the numeric results for the acoustic streaming effects are more problematic...
International Development Research Centre (IDRC) Digital Library (Canada)
Nairobi, Kenya. 28 Adapting Fishing Policy to Climate Change with the Aid of Scientific and Endogenous Knowledge. Cap Verde, Gambia,. Guinea, Guinea Bissau,. Mauritania and Senegal. Environment and Development in the Third World. (ENDA-TM). Dakar, Senegal. 29 Integrating Indigenous Knowledge in Climate Risk ...
Interpretive Research Aiming at Theory Building: Adopting and Adapting the Case Study Design
Diaz Andrade, Antonio
2009-01-01
Although the advantages of case study design are widely recognised, its original positivist underlying assumptions may mislead interpretive researchers aiming at theory building. The paper discusses the limitations of the case study design for theory building and explains how grounded theory systemic process adds to the case study design. The…
Adaptive mastery testing using the Rasch model and Bayesian sequential decision theory
Glas, Cornelis A.W.; Vos, Hendrik J.
1998-01-01
A version of sequential mastery testing is studied in which response behavior is modeled by an item response theory (IRT) model. First, a general theoretical framework is sketched that is based on a combination of Bayesian sequential decision theory and item response theory. A discussion follows on
Hardy, B; Berrou, A; Guilbaud, S; Raybaut, M; Godard, A; Lefebvre, M
2011-03-01
We report on a nested-cavity, doubly resonant optical parametric oscillator (NesCOPO) architecture for widely tunable, mid-IR, single-frequency generation. By use of an achromatic phase-adapted double-pass pumping scheme, this new, low-threshold, semimonolithic architecture only requires two free-standing cavity mirrors and a nonlinear crystal with a mirror coating deposited on its input facet while the other facet is antireflection coated. It is thus as simple and compact as any basic linear optical parametric oscillator cavity, is easily tunable, and displays low sensitivity to mechanical vibrations. Using a high-repetition-rate (4.8 kHz) microlaser as the pump source of the NesCOPO, we demonstrate a compact source that provides pulsed, stable single-frequency output over a wide spectral range (3.8-4.3 μm) with a high peak power (up to 50 W), which are properties well suited for practical gas sensing applications.
Directory of Open Access Journals (Sweden)
Luciane Stallivieri
2015-11-01
Full Text Available Students from around the world are increasingly interested in learning new languages and be inserted in different cultures, increasing the numbers of international mobility. However, when traveling to another country, cultural differences are strongly perceived, even if in different ways, influencing the adaptation process. Given the importance and growth of the international academic mobility, this study analyzes the process of cultural adaptation of students in mobility, considering the assumptions of the theory of curves "U" and "W". As for the methodology, it is a descriptive research with quantitative approach. Data collection was conducted through closed questionnaires sent to international students from different countries who have studied or are still studying in a Brazilian Institution of Higher Education. The results showed that after the stage of culture shock, students feel more connected to local culture, make more friends and feel more confident. It was confirmed also that almost all international students managed to adapt well to local customs.
Use of adaptive diffusion theory based monitors in optimizing boiling water reactor core designs
International Nuclear Information System (INIS)
Congdon, S.P.; Martin, C.L.; Crowther, R.L.
1988-01-01
Three-dimensional coarse mesh models are routinely used to predict the performance of boiling water reactors. In the adaptive monitory model, the three-dimensional solutions are permanently adapted to incore probe data. The corrections resulting from the adaptive process lead to reliable predictions of future reactor states. The corrections can also be carried forward to future operating cycles. This can shorten the time required to introduce an validate new design and operating strategy improvements. (orig.) [de
Directory of Open Access Journals (Sweden)
Axel Leon
2008-04-01
Full Text Available Abstract In less than two decades, first-pass perfusion cardiovascular magnetic resonance (CMR has undergone a wide range of changes with the development and availability of improved hardware, software, and contrast agents, in concert with a better understanding of the mechanisms of contrast enhancement. The following review provides a perspective of the historical development of first-pass CMR, the developments in pulse sequence design and contrast agents, the relevant animal models used in early preclinical studies, the mechanism of artifacts, the differences between 1.5T and 3T scanning, and the relevant clinical applications and protocols. This comprehensive overview includes a summary of the past clinical performance of first-pass perfusion CMR and current clinical applications using state-of-the-art methodologies.
Application of chiral resonance Lagrangian theories to the muon g-2
Energy Technology Data Exchange (ETDEWEB)
Jegerlehner, Fred [Humboldt-Universitaet, Berlin (Germany). Inst. fuer Physik; Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2013-12-15
We think that phenomenological resonance Lagrangian models, constrained by global fits from low energy hadron reaction data, can help to improve muon g-2 predictions. The main issue are those contributions which cannot be calculated by perturbative means: the hadronic vacuum polarization (HVP) effects and the hadronic light-by-light (HLbL) scattering contribution. I review recent progress in the evaluation of the HVP contribution within the broken Hidden Local Symmetry (HLS) framework, worked out in collaboration with M. Benayoun, P. David and L. Del-Buono. Our HLS driven estimate reads a{sub {mu}}{sup LO} {sup had} = (688.60{+-}4.24) . 10{sup -10} and we find a{sub {mu}}{sup the} = (11659177.65{+-}5.76) . 10{sup -10}.
Arias, R. E.; Mills, D. L.
2009-04-01
We present theoretical studies of ferromagnetic resonance in perpendicularly magnetized nanodisks, wherein spin waves are excited through the ac modulation of the dc transport current injected into the disk. We have nanopillars in mind in our analysis, where spin-polarized current is injected from a metallic ferromagnet elsewhere in the structure. We argue that in a limit described, the modulation of the Oersted field generated by the transport current is the dominant spin-wave excitation mechanism, and our studies explore this limit. We calculate the critical current above which the nominal ferromagnetic state becomes unstable through studies of the linewidth of the lowest spin-wave mode, which vanishes when the critical current is reached. We find that as the applied Zeeman field H0 is decreased from values above 4πMS , the critical current has a minimum when H0˜4πMS to increase for values of the external field below this value.
Durai, Mithila; O'Keeffe, Mary G; Searchfield, Grant D
2017-03-01
Existing evidence suggests a strong relationship between tinnitus and emotion. The objective of this study was to examine the effects of short-term emotional changes along valence and arousal dimensions on tinnitus outcomes. Emotional stimuli were presented in two different modalities: auditory and visual. The authors hypothesized that (1) negative valence (unpleasant) stimuli and/or high arousal stimuli will lead to greater tinnitus loudness and annoyance than positive valence and/or low arousal stimuli, and (2) auditory emotional stimuli, which are in the same modality as the tinnitus, will exhibit a greater effect on tinnitus outcome measures than visual stimuli. Auditory and visual emotive stimuli were administered to 22 participants (12 females and 10 males) with chronic tinnitus, recruited via email invitations send out to the University of Auckland Tinnitus Research Volunteer Database. Emotional stimuli used were taken from the International Affective Digital Sounds- Version 2 (IADS-2) and the International Affective Picture System (IAPS) (Bradley and Lang, 2007a, 2007b). The Emotion Regulation Questionnaire (Gross and John, 2003) was administered alongside subjective ratings of tinnitus loudness and annoyance, and psychoacoustic sensation level matches to external sounds. Males had significantly different emotional regulation scores than females. Negative valence emotional auditory stimuli led to higher tinnitus loudness ratings in males and females and higher annoyance ratings in males only; loudness matches of tinnitus remained unchanged. The visual stimuli did not have an effect on tinnitus ratings. The results are discussed relative to the Adaptation Level Theory Model of Tinnitus. The results indicate that the negative valence dimension of emotion is associated with increased tinnitus magnitude judgements and gender effects may also be present, but only when the emotional stimulus is in the auditory modality. Sounds with emotional associations may be
How adaptive learning affects evolution: reviewing theory on the Baldwin effect
Sznajder, B.; Sabelis, M.W.; Egas, M.
2012-01-01
We review models of the Baldwin effect, i.e., the hypothesis that adaptive learning (i.e., learning to improve fitness) accelerates genetic evolution of the phenotype. Numerous theoretical studies scrutinized the hypothesis that a non-evolving ability of adaptive learning accelerates evolution of
Mainali, Laxman; Sahu, Indra; Earle, Keith
2008-03-01
Relativistic density functional theory calculations of electron paramagnetic resonance (EPR) parameters using a variety of basis sets have been computed for the model systems Vanadyl acetyl acetonate and Copper acetyl acetonate using the ORCA program. The basis set dependence of g and A tensor calculations for Vanadyl acetyl acetonate and Copper acetyl acetonate were studied using Pople Style and Ahlrichs basis sets in Local and gradient corrected functionals (BP86 and PWP) and Hybrid functionals (B3LYP and PW1PW). The PW1PW hybrid functional gives the best values for VO(acac)2 using the TZV basis set and for Cu(acac)2 using the 6-311G(d) basis set. The calculated A values with PW1PW hybrid functional for VO(acac)2 and Local and gradient corrected functional (BP86) for Cu(acac)2 with same basis set (DZ) give better results than previously reported values using the Amsterdam Density Functional Theory (ADF) Software. Our calculated g and A tensor values are in good agreement with the values determined from experiment.
Theory and method for weak signal detection in engineering practice based on stochastic resonance
Zhao, Wenli; Wang, Linze; Fan, Jian
2017-11-01
In this paper, the Kramers rate was derived using the Fokker-Planck (FP) equation with the condition of adiabatic approximation (the amplitude and frequency of signal detected are small ≪ 1) and the signal-to-noise ratio (SNR) was proved by means of Fourier transform and the power spectrum in bistable system. This is a concise and superior method to demonstrate the Kramers rate and SNR compared to the past methods. It is convenient for readers to understand. The SNR of the bistable system obtained shows that stochastic resonance (SR) can be used to realize energy transition from noise to a periodic signal under the adiabatic approximation condition. Therefore, SR could enhance the SNR of the output signal. The signal modulation technique was employed to transform the large frequency components into a small parameter signal to meet the adiabatic approximation requirement. Furthermore, we have designed the model of modulator. The simulation results show that the modulation method can generate SR in a bistable system and detect weak signals with large parameters from strong noise background.
Jung, Rex E; Gasparovic, Charles; Chavez, Robert S; Flores, Ranee A; Smith, Shirley M; Caprihan, Arvind; Yeo, Ronald A
2009-04-22
A broadly accepted definition of creativity refers to the production of something both novel and useful within a given social context. Studies of patients with neurological and psychiatric disorders and neuroimaging studies of healthy controls have each drawn attention to frontal and temporal lobe contributions to creativity. Based on previous magnetic resonance (MR) spectroscopy studies demonstrating relationships between cognitive ability and concentrations of N-acetyl-aspartate (NAA), a common neurometabolite, we hypothesized that NAA assessed in gray and white matter (from a supraventricular slab) would relate to laboratory measures of creativity. MR imaging and divergent thinking measures were obtained in a cohort of 56 healthy controls. Independent judges ranked the creative products of each participant, from which a "Composite Creativity Index" (CCI) was created. Different patterns of correlations between NAA and CCI were found in higher verbal ability versus lower verbal ability participants, providing neurobiological support for a critical "threshold" regarding the relationship between intelligence and creativity. To our knowledge, this is the first report assessing the relationship between brain chemistry and creative cognition, as measured with divergent thinking, in a cohort comprised exclusively of normal, healthy participants.
Jung, Rex E.; Gasparovic, Charles; Chavez, Robert S.; Flores, Ranee A.; Smith, Shirley M.; Caprihan, Arvind; Yeo, Ronald A.
2009-01-01
A broadly accepted definition of creativity refers to the production of something both novel and useful within a given social context. Studies of patients with neurological and psychiatric disorders and neuroimaging studies of healthy controls have each drawn attention to frontal and temporal lobe contributions to creativity. Based on previous magnetic resonance (MR) spectroscopy studies demonstrating relationships between cognitive ability and concentrations of N-acetyl-aspartate (NAA), a common neurometabolite, we hypothesized that NAA assessed in gray and white matter (from a supraventricular slab) would relate to laboratory measures of creativity. MR imaging and divergent thinking measures were obtained in a cohort of 56 healthy controls. Independent judges ranked the creative products of each participant, from which a “Composite Creativity Index” (CCI) was created. Different patterns of correlations between NAA and CCI were found in higher verbal ability versus lower verbal ability participants, providing neurobiological support for a critical “threshold” regarding the relationship between intelligence and creativity. To our knowledge, this is the first report assessing the relationship between brain chemistry and creative cognition, as measured with divergent thinking, in a cohort comprised exclusively of normal, healthy participants. PMID:19386928
Toward a Mechanics of Adaptive Behavior: Evolutionary Dynamics and Matching Theory Statics
McDowell, J. J.; Popa, Andrei
2010-01-01
One theory of behavior dynamics instantiates the idea that behavior evolves in response to selection pressure from the environment in the form of reinforcement. This computational theory implements Darwinian principles of selection, reproduction, and mutation, which operate on a population of potential behaviors by means of a genetic algorithm.…
Hu, Zhongwei; Autschbach, Jochen; Jensen, Lasse
2014-09-28
Resonance hyper-Rayleigh scattering (HRS) of molecules and metal clusters have been simulated based on a time-dependent density functional theory approach. The resonance first-order hyperpolarizability (β) is obtained by implementing damped quadratic response theory using the (2n + 1) rule. To test this implementation, the prototypical dipolar molecule para-nitroaniline (p-NA) and the octupolar molecule crystal violet are used as benchmark systems. Moreover, small silver clusters Ag 8 and Ag 20 are tested with a focus on determining the two-photon resonant enhancement arising from the strong metal transition. Our results show that, on a per atom basis, the small silver clusters possess two-photon enhanced HRS comparable to that of larger nanoparticles. This finding indicates the potential interest of using small metal clusters for designing new nonlinear optical materials.
The nucleon and Delta-resonance masses in relativistic chiral effective-field theory
Energy Technology Data Exchange (ETDEWEB)
V. Pascalutsa; M. Vanderhaeghen
2005-11-28
We study the chiral behavior of the nucleon and De-isobar masses within a manifestly covariant chiral effective-field theory, consistent with the analyticity principle. We compute the {pi} N and {pi}{Delta} one-loop contributions to the mass and field-normalization constant, and find that they can be described in terms of universal relativistic loop functions, multiplied by appropriate spin, isospin and coupling constants. We show that these relativistic one-loop corrections, when properly renormalized, obey the chiral power-counting and vanish in the chiral limit. The results including only the {pi} N-loop corrections compare favorably with the lattice QCD data for the pion-mass dependence of the nucleon and De masses, while inclusion of the {pi}/De loops tends to spoil this agreement.
Directory of Open Access Journals (Sweden)
Carlos David Navarrete
2005-01-01
Full Text Available Adherence to ingroup ideology increases after exposure to death-related stimuli, a reaction that proponents of terror management theory (TMT explain as a psychological defense against the uniquely human existential fear of death. We argue that existential concerns are not the relevant issue; rather, such concepts can be subsumed under a larger category of adaptive challenges that prime coalitional thinking. We suggest that increases in adherence to ingroup ideology in response to adaptive challenges are manifestations of normative mental representations emanating from psychological systems designed to enhance coordination and membership in social groups. In providing an alternative to TMT, we (1 explain why the theory is inconsistent with contemporary evolutionary biology, (2 demonstrate that mortality-salience does not have the unique evocative powers ascribed to it by TMT advocates, and (3 discuss our approach to coalitional psychology, a framework consistent with modern evolutionary theory and informed by a broad understanding of cultural variation, can be employed to help account for both the corpus of results in TMT research and the growing body of findings inconsistent with TMT's predictions.
Moore, Tria; Norman, Paul; Harris, Peter R; Makris, Michael
2006-11-01
Venous thrombosis is a common and life-threatening disease that has received little attention in health psychology. The present study applied the theory of cognitive adaptation (TCA) to examine patients' reactions to venous thrombosis. Patients (N = 123) aged 16-84 recruited from anticoagulation units in the north of England completed measures of TCA constructs (meaning, mastery, self-esteem and optimism) and various outcome variables (anxiety, depression, thrombosis worries and quality of life) within 1 month of their thrombosis. The TCA explained large and significant amounts of variance in the outcome variables. In line with expectations, mastery, self-esteem and optimism were associated with positive adjustment. However, meaning was associated with elevated levels of distress. The results are discussed in relation to the search for meaning and the use of different control strategies in the early phases of adaptation to thrombosis.
Filippidis, Stavros K.; Tsoukalas, Ioannis A.
2009-01-01
An adaptive educational system that uses adaptive presentation is presented. In this system fragments of different images present the same content and the system can choose the one most relevant to the user based on the sequential-global dimension of Felder-Silverman's learning style theory. In order to retrieve the learning style of each student…
Current Understanding of the Formation and Adaptation of Metabolic Systems Based on Network Theory
Directory of Open Access Journals (Sweden)
Kazuhiro Takemoto
2012-07-01
Full Text Available Formation and adaptation of metabolic networks has been a long-standing question in biology. With recent developments in biotechnology and bioinformatics, the understanding of metabolism is progressively becoming clearer from a network perspective. This review introduces the comprehensive metabolic world that has been revealed by a wide range of data analyses and theoretical studies; in particular, it illustrates the role of evolutionary events, such as gene duplication and horizontal gene transfer, and environmental factors, such as nutrient availability and growth conditions, in evolution of the metabolic network. Furthermore, the mathematical models for the formation and adaptation of metabolic networks have also been described, according to the current understanding from a perspective of metabolic networks. These recent findings are helpful in not only understanding the formation of metabolic networks and their adaptation, but also metabolic engineering.
Non-identifier based adaptive control in mechatronics theory and application
Hackl, Christoph M
2017-01-01
This book introduces non-identifier-based adaptive control (with and without internal model) and its application to the current, speed and position control of mechatronic systems such as electrical synchronous machines, wind turbine systems, industrial servo systems, and rigid-link, revolute-joint robots. In mechatronics, there is often only rough knowledge of the system. Due to parameter uncertainties, nonlinearities and unknown disturbances, model-based control strategies can reach their performance or stability limits without iterative controller design and performance evaluation, or system identification and parameter estimation. The non-identifier-based adaptive control presented is an alternative that neither identifies the system nor estimates its parameters but ensures stability. The adaptive controllers are easy to implement, compensate for disturbances and are inherently robust to parameter uncertainties and nonlinearities. For controller implementation only structural system knowledge (like relativ...
Directory of Open Access Journals (Sweden)
Langemeyer, Ines
2017-03-01
Full Text Available In the first half of the 20th century, the field concept was part of theoretical and methodological innovations in physics, gestalt theory as well as epic theatre as introduced by Bertolt Brecht. Another reference is the psychology of Kurt Lewin. In what ways Brecht took notice of Lewin’s research, especially his demand of a transition from Aristotelian to Galileian thought is reconstructed within the context of paradigm shifts fostered by logical empiricism, gestalt theory and physics. Lewin’s argumentation of an advanced understanding of the lawfulness of societal and psychological processes is placed in the center and traced back as an inspiration to Brecht’s writings. Vice versa, the article investigates in what ways Brecht’s theoretical writings and adaptations of Lewin’s approach can be reconsidered as a source for psychological theorizing.
Relativistic theory of nuclear magnetic resonance parameters in a Gaussian basis representation.
Kutzelnigg, Werner; Liu, Wenjian
2009-07-28
The calculation of NMR parameters from relativistic quantum theory in a Gaussian basis expansion requires some care. While in the absence of a magnetic field the expansion in a kinetically balanced basis converges for the wave function in the mean and for the energy with any desired accuracy, this is not necessarily the case for magnetic properties. The results for the magnetizability or the nuclear magnetic shielding are not even correct in the nonrelativistic limit (nrl) if one expands the original Dirac equation in a kinetically balanced Gaussian basis. This defect disappears if one starts from the unitary transformed Dirac equation as suggested by Kutzelnigg [Phys. Rev. A 67, 032109 (2003)]. However, a new difficulty can arise instead if one applies the transformation in the presence of the magnetic field of a point nucleus. If one decomposes certain contributions, the individual terms may diverge, although their sum is regular. A controlled cancellation may become difficult and numerical instabilities can arise. Various ways exist to avoid these singularities and at the same time get the correct nrl. There are essentially three approaches intermediate between the transformed and the untransformed formulation, namely, the bispinor decomposition, the decomposition of the lower component, and the hybrid unitary transformation partially at operator and partially at matrix level. All three possibilities were first considered by Xiao et al. [J. Chem. Phys. 126, 214101 (2007)] in a different context and in a different nomenclature. Their analysis and classification in a more general context are given here for the first time. Use of an extended balanced basis has no advantages and has other drawbacks and is not competitive, while the use of a restricted magnetic balance basis can be justified.
Livneh, Hanoch; Bishop, Malachy; Anctil, Tina M.
2014-01-01
Purpose: In this article, we describe how four recent models of psychosocial adaptation to chronic illness and disability (CID) could be fruitfully conceptualized and compared by resorting to the general framework of Lewin's field theory--a theory frequently regarded as a precursor and the primary impetus to the development of the field of…
Energy Technology Data Exchange (ETDEWEB)
Andreozzi, J; Bruza, P; Saunders, S; Pogue, B [Dartmouth College, Hanover, NH (United States); Mooney, K; Curcuru, A; Green, O [Washington University School of Medicine, Saint Louis, MO (United States); Gladstone, D [Dartmouth-Hitchcock Med. Ctr., Lebanon, NH (Lebanon)
2016-06-15
Purpose: To investigate the viability of using Cherenkov imaging as a fast and robust method for quality assurance tests in the presence of a magnetic field, where other instruments can be limited. Methods: Water tank measurements were acquired from a clinically utilized adaptive magnetic resonance image guided radiation therapy (MR-IGRT) machine with three multileaf-collimator equipped 60Co sources. Cherenkov imaging used an intensified charge coupled device (ICCD) camera placed 3.5m from the treatment isocenter, looking down the bore of the 0.35T MRI into a water tank. Images were post-processed to make quantitative comparison between Cherenkov light intensity with both film and treatment planning system predictions, in terms of percent depth dose curves as well as lateral beam profile measurements. A TG-119 commissioning test plan (C4: C-Shape) was imaged in real-time at 6.33 frames per second to investigate the temporal and spatial resolution of the Cherenkov imaging technique. Results: A .33mm/pixel Cherenkov image resolution was achieved across 1024×1024 pixels in this setup. Analysis of the Cherenkov image of a 10.5×10.5cm treatment beam in the water tank successfully measured the beam width at the depth of maximum dose within 1.2% of the film measurement at the same point. The percent depth dose curve for the same beam was on average within 2% of ionization chamber measurements for corresponding depths between 3–100mm. Cherenkov video of the TG-119 test plan provided qualitative agreement with the treatment planning system dose predictions, and a novel temporal verification of the treatment. Conclusions: Cherenkov imaging was successfully used to make QA measurements of percent depth dose curves and cross beam profiles of MRI-IGRT radiotherapy machines after only several seconds of beam-on time and data capture; both curves were extracted from the same data set. Video-rate imaging of a dynamic treatment plan provided new information regarding temporal
Energy Technology Data Exchange (ETDEWEB)
Schmid, Maximilian P.; Fidarova, Elena [Dept. of Radiotherapy, Comprehensive Cancer Center, Medical Univ. of Vienna, Vienna (Austria)], e-mail: maximilian.schmid@akhwien.at; Poetter, Richard [Dept. of Radiotherapy, Comprehensive Cancer Center, Medical Univ. of Vienna, Vienna (Austria); Christian Doppler Lab. for Medical Radiation Research for Radiation Oncology, Medical Univ. of Vienna (Austria)] [and others
2013-10-15
Purpose: To investigate the impact of magnetic resonance imaging (MRI)-morphologic differences in parametrial infiltration on tumour response during primary radio chemotherapy in cervical cancer. Material and methods: Eighty-five consecutive cervical cancer patients with FIGO stages IIB (n = 59) and IIIB (n = 26), treated by external beam radiotherapy ({+-}chemotherapy) and image-guided adaptive brachytherapy, underwent T2-weighted MRI at the time of diagnosis and at the time of brachytherapy. MRI patterns of parametrial tumour infiltration at the time of diagnosis were assessed with regard to predominant morphology and maximum extent of parametrial tumour infiltration and were stratified into five tumour groups (TG): 1) expansive with spiculae; 2) expansive with spiculae and infiltrating parts; 3) infiltrative into the inner third of the parametrial space (PM); 4) infiltrative into the middle third of the PM; and 5) infiltrative into the outer third of the PM. MRI at the time of brachytherapy was used for identifying presence (residual vs. no residual disease) and signal intensity (high vs. intermediate) of residual disease within the PM. Left and right PM of each patient were evaluated separately at both time points. The impact of the TG on tumour remission status within the PM was analysed using {chi}2-test and logistic regression analysis. Results: In total, 170 PM were analysed. The TG 1, 2, 3, 4, 5 were present in 12%, 11%, 35%, 25% and 12% of the cases, respectively. Five percent of the PM were tumour-free. Residual tumour in the PM was identified in 19%, 68%, 88%, 90% and 85% of the PM for the TG 1, 2, 3, 4, and 5, respectively. The TG 3 - 5 had significantly higher rates of residual tumour in the PM in comparison to TG 1 + 2 (88% vs. 43%, p < 0.01). Conclusion: MRI-morphologic features of PM infiltration appear to allow for prediction of tumour response during external beam radiotherapy and chemotherapy. A predominantly infiltrative tumour spread at the
Adaptive sex allocation in birds : The complexities of linking theory and practice
Komdeur, Jan; Pen, Ido
2002-01-01
We review some recent theoretical and empirical developments in the study of sex allocation in birds. The advent of reliable molecular sexing techniques has led to a sharp increase in the number of studies that report biased offspring sex ratios in birds. However, compelling evidence for adaptive
Howes, Andrew; Lewis, Richard L.; Vera, Alonso
2009-01-01
The authors assume that individuals adapt rationally to a utility function given constraints imposed by their cognitive architecture and the local task environment. This assumption underlies a new approach to modeling and understanding cognition--cognitively bounded rational analysis--that sharpens the predictive acuity of general, integrated…
Adaptive synchronization of chaos in permanent magnet synchronous motors based on passivity theory
International Nuclear Information System (INIS)
Wei Du-Qu; Luo Xiao-Shu; Zhang Bo
2012-01-01
An adaptive synchronization control method is proposed for chaotic permanent magnet synchronous motors based on the property of a passive system. We prove that the controller makes the synchronization error system between the driving and the response systems not only passive but also asymptotically stable. The simulation results show that the proposed method is effective and robust against uncertainties in the systemic parameters. (general)
Diffusion theory for light propagation in biological tissue : limitations and adaptations
Graaff, R; Hoenders, BJ; Tuchin, VV
2005-01-01
Diffusion theory is an approximation of the equation of radiative transport, that is used to describe light propagation in turbid media. This approximation is very popular because of its simplicity, possibilities to describe time-resolved light propagation, and for its appeal to physical intuition.
Energy Technology Data Exchange (ETDEWEB)
Ghobadi, Ahmadreza F.; Elliott, J. Richard, E-mail: elliot1@uakron.edu [Department of Chemical and Biomolecular Engineering, The University of Akron, Akron, Ohio 44325 (United States)
2013-12-21
In this work, we aim to develop a version of the Statistical Associating Fluid Theory (SAFT)-γ equation of state (EOS) that is compatible with united-atom force fields, rather than experimental data. We rely on the accuracy of the force fields to provide the relation to experimental data. Although, our objective is a transferable theory of interfacial properties for soft and fused heteronuclear chains, we first clarify the details of the SAFT-γ approach in terms of site-based simulations for homogeneous fluids. We show that a direct comparison of Helmholtz free energy to molecular simulation, in the framework of a third order Weeks-Chandler-Andersen perturbation theory, leads to an EOS that takes force field parameters as input and reproduces simulation results for Vapor-Liquid Equilibria (VLE) calculations. For example, saturated liquid density and vapor pressure of n-alkanes ranging from methane to dodecane deviate from those of the Transferable Potential for Phase Equilibria (TraPPE) force field by about 0.8% and 4%, respectively. Similar agreement between simulation and theory is obtained for critical properties and second virial coefficient. The EOS also reproduces simulation data of mixtures with about 5% deviation in bubble point pressure. Extension to inhomogeneous systems and united-atom site types beyond those used in description of n-alkanes will be addressed in succeeding papers.
Ghobadi, Ahmadreza F; Elliott, J Richard
2013-12-21
In this work, we aim to develop a version of the Statistical Associating Fluid Theory (SAFT)-γ equation of state (EOS) that is compatible with united-atom force fields, rather than experimental data. We rely on the accuracy of the force fields to provide the relation to experimental data. Although, our objective is a transferable theory of interfacial properties for soft and fused heteronuclear chains, we first clarify the details of the SAFT-γ approach in terms of site-based simulations for homogeneous fluids. We show that a direct comparison of Helmholtz free energy to molecular simulation, in the framework of a third order Weeks-Chandler-Andersen perturbation theory, leads to an EOS that takes force field parameters as input and reproduces simulation results for Vapor-Liquid Equilibria (VLE) calculations. For example, saturated liquid density and vapor pressure of n-alkanes ranging from methane to dodecane deviate from those of the Transferable Potential for Phase Equilibria (TraPPE) force field by about 0.8% and 4%, respectively. Similar agreement between simulation and theory is obtained for critical properties and second virial coefficient. The EOS also reproduces simulation data of mixtures with about 5% deviation in bubble point pressure. Extension to inhomogeneous systems and united-atom site types beyond those used in description of n-alkanes will be addressed in succeeding papers.
Adaptive mastery testing using a multidimensional IRT model and Bayesian sequential decision theory
Glas, Cornelis A.W.; Vos, Hendrik J.
2000-01-01
This paper focuses on a version of sequential mastery testing (i.e., classifying students as a master/nonmaster or continuing testing and administering another item or testlet) in which response behavior is modeled by a multidimensional item response theory (IRT) model. First, a general theoretical
Boutalis, Yiannis; Kottas, Theodore; Christodoulou, Manolis A
2014-01-01
Presenting current trends in the development and applications of intelligent systems in engineering, this monograph focuses on recent research results in system identification and control. The recurrent neurofuzzy and the fuzzy cognitive network (FCN) models are presented. Both models are suitable for partially-known or unknown complex time-varying systems. Neurofuzzy Adaptive Control contains rigorous proofs of its statements which result in concrete conclusions for the selection of the design parameters of the algorithms presented. The neurofuzzy model combines concepts from fuzzy systems and recurrent high-order neural networks to produce powerful system approximations that are used for adaptive control. The FCN model stems from fuzzy cognitive maps and uses the notion of “concepts” and their causal relationships to capture the behavior of complex systems. The book shows how, with the benefit of proper training algorithms, these models are potent system emulators suitable for use in engineering s...
Adaptive State Feedback—Theory and Application for Wind Turbine Control
Directory of Open Access Journals (Sweden)
Kaman Thapa Magar
2017-12-01
Full Text Available A class of adaptive disturbance tracking controllers (ADTCs is augmented with disturbance and state estimation and adaptive state feedback, in which a controller and estimator, which are designed on the basis of a lower-order model, are used to control a higher-order nonlinear plant. The ADTC requires that the plant be almost strict positive real (ASPR to ensure stability. In this paper, we show that the ASPR property of a plant is retained with the addition of disturbance and state estimation and state feedback, thereby ensuring the stability of the augmented system. The proposed adaptive controller with augmentation is presented in the context of maximum power extraction from a wind turbine in a low-wind-speed operation region. A simulation and comparative study on the National Renewable Energy Laboratory’s (NREL’s 5 MW nonlinear wind turbine model with an existing baseline Proportional-Integral-Derivative(PID controller shows that the proposed controller is more effective than the existing baseline PID controller.
Directory of Open Access Journals (Sweden)
Kathi K. Beratan
2014-03-01
Full Text Available Translating the attractive concept of collaborative adaptive management (CAM into practice has proven very difficult. The papers included in this Special Feature explore why this is true and suggest how the challenges might be addressed. This summary highlights common themes, major challenges, and implications for research and practice. Many of the included papers emphasize the central importance of collaboration and stakeholder engagement as a response to complexity and uncertainty. Collectively, the papers make the case that a lack of knowledge about how to manage the human dynamics of comanagement poses a major challenge to implementing CAM. Human activities are the primary drivers of system change in most natural resource management systems, so attention to human dynamics is essential for developing useful change hypotheses and leading indicators that can provide useful and timely feedback for adaptive management. Institutions need to evolve to support adaptive and collaborative management processes. This will require thoughtful design of CAM processes, along with commitment of sufficient time and resources. Implementation challenges should be considered as a major focus for research rather than as simply barriers to progress. More effective ways of capturing practitioners' experiential knowledge are required to improve the practice of CAM. This Special Feature suggests that the concept of a CAM practitioners' journal has promise, but realization of that promise will require careful attention to the needs of and constraints on practitioners.
Adaptive fuzzy control of underactuated robotic systems with the use of differential flatness theory
Rigatos, Gerasimos G.
2013-10-01
An adaptive fuzzy controller is designed for a class of underactuated nonlinear robotic manipulators, under the constraint that the system's model is unknown. The control algorithm aims at satisfying the H∞ tracking performance criterion, which means that the influence of the modeling errors and the external disturbances on the tracking error is attenuated to an arbitrary desirable level. After transforming the robotic system into the canonical form, the resulting control inputs are shown to contain nonlinear elements which depend on the system's parameters. The nonlinear terms which appear in the control inputs are approximated with the use of neuro-fuzzy networks. It is shown that a suitable learning law can be defined for the aforementioned neuro-fuzzy approximators so as to preserve the closed-loop system stability. With the use of Lyapunov stability analysis it is proven that the proposed adaptive fuzzy control scheme results in H∞ tracking performance. The efficiency of the proposed adaptive fuzzy control scheme is checked in the case of a 2-DOF planar robotic manipulator that has the structure of a closed-chain mechanism.
Sedlak, Robert; Řezáč, Jan
2017-04-11
In density functional theory-based symmetry-adapted perturbation theory (DFT-SAPT) interaction energy calculations, the most demanding step is the calculation of the London dispersion term. For this bottleneck to be avoided and DFT-SAPT to be made applicable to larger systems, the ab initio dispersion terms can be replaced by one calculated empirically at an almost negligible cost ( J. Phys. Chem. A 2011 ; 115 , 11321 - 11330 ). We present an update of this approach that improves accuracy and makes the method applicable to a wider range of systems. It is based on Grimme's D3 dispersion correction for DFT, where the damping function is changed to one suitable for the calculation of the complete dispersion energy. The best results have been achieved with the Tang-Toennies damping function. It has been parametrized on the S66×8 data set for which we report density fitting DFT-SAPT/aug-cc-pVTZ interaction energy decomposition. The method has been validated on a diverse set of noncovalent systems including difficult cases such as very compact noncovalent complexes of charge-transfer type. The root-mean-square errors in the complete test set are 0.73 and 0.42 kcal mol -1 when charge-transfer complexes are excluded. The proposed empirical dispersion terms can also be used outside the DFT-SAPT framework, e.g., for the estimation of the amount of dispersion in a calculation where only the total interaction energy is known.
Adapting the Theory of Visual Attention (TVA) to model auditory attention
DEFF Research Database (Denmark)
Roberts, Katherine L.; Andersen, Tobias; Kyllingsbæk, Søren
Mathematical and computational models have provided useful insights into normal and impaired visual attention, but less progress has been made in modelling auditory attention. We are developing a Theory of Auditory Attention (TAA), based on an influential visual model, the Theory of Visual...... Attention (TVA). We report that TVA provides a good fit to auditory data when the stimuli are closely matched to those used in visual studies. In the basic visual TVA task, participants view a brief display of letters and are asked to report either all of the letters (whole report) or a subset of letters (e.......g., the red letters; partial report). For the auditory task, we used dichotic, concurrently-presented synthesised vowels. These auditory stimuli are closely-matched to the visual stimuli, in that they are simultaneous, separated in space, and unchanging over time. We found that TVA could successfully model...
Piefke, Christoph; Lechermann, Frank
2018-03-01
The theory of correlated electron systems on a lattice proves notoriously complicated because of the exponential growth of Hilbert space. Mean-field approaches provide valuable insight when the self-energy has a dominant local structure. Additionally, the extraction of effective low-energy theories from the generalized many-body representation is highly desirable. In this respect, the rotational-invariant slave-boson (RISB) approach in its mean-field formulation enables versatile access to correlated lattice problems. However, in its original form, due to numerical complexity, the RISB approach is limited to about three correlated orbitals per lattice site. We thus present a thorough symmetry-adapted advancement of RISB theory, suited to efficiently deal with multiorbital Hubbard Hamiltonians for complete atomic-shell manifolds. It is utilized to study the intriguing problem of Hund's physics for three- and especially five-orbital manifolds on the correlated lattice, including crystal-field terms as well as spin-orbit interaction. The well-known Janus-face phenomenology, i.e., strengthening of correlations at smaller-to-intermediate Hubbard U accompanied by a shift of the Mott transition to a larger U value, has a stronger signature and more involved multiplet resolution for five-orbital problems. Spin-orbit interaction effectively reduces the critical local interaction strength and weakens the Janus-face behavior. Application to the realistic challenge of Fe chalcogenides underlines the subtle interplay of the orbital degrees of freedom in these materials.
山口, 朝彦; 桃木, 悟; ジャンバル, オダゲレル; 松崎, 勇人; 上滝, 祐介; 今道, 統也; 金丸, 邦康
2011-01-01
Thermophysical properties of hydrogen are needed to design equipments associated with hydrogen. The speed of sound is one of thermophysical properties itself and includes the important information of thermophysical properties, such as specific heat at ideal gas. In this paper, the measurement facility for sound speed of hydrogen with spherical acoustic resonator which we made and the theory of acoustic measurement are explained. We have calibrated the radius of the spherical cavity in this ap...
Symmetry Adaptation of the Rotation-Vibration Theory for Linear Molecules
Directory of Open Access Journals (Sweden)
Katy L. Chubb
2018-04-01
Full Text Available A numerical application of linear-molecule symmetry properties, described by the D ∞ h point group, is formulated in terms of lower-order symmetry groups D n h with finite n. Character tables and irreducible representation transformation matrices are presented for D n h groups with arbitrary n-values. These groups can subsequently be used in the construction of symmetry-adapted ro-vibrational basis functions for solving the Schrödinger equations of linear molecules. Their implementation into the symmetrisation procedure based on a set of “reduced” vibrational eigenvalue problems with simplified Hamiltonians is used as a practical example. It is shown how the solutions of these eigenvalue problems can also be extended to include the classification of basis-set functions using ℓ, the eigenvalue (in units of ℏ of the vibrational angular momentum operator L ^ z . This facilitates the symmetry adaptation of the basis set functions in terms of the irreducible representations of D n h . 12 C 2 H 2 is used as an example of a linear molecule of D ∞ h point group symmetry to illustrate the symmetrisation procedure of the variational nuclear motion program Theoretical ROVibrational Energies (TROVE.
Development of model reference adaptive control theory for electric power plant control applications
Energy Technology Data Exchange (ETDEWEB)
Mabius, L.E.
1982-09-15
The scope of this effort includes the theoretical development of a multi-input, multi-output (MIMO) Model Reference Control (MRC) algorithm, (i.e., model following control law), Model Reference Adaptive Control (MRAC) algorithm and the formulation of a nonlinear model of a typical electric power plant. Previous single-input, single-output MRAC algorithm designs have been generalized to MIMO MRAC designs using the MIMO MRC algorithm. This MRC algorithm, which has been developed using Command Generator Tracker methodologies, represents the steady state behavior (in the adaptive sense) of the MRAC algorithm. The MRC algorithm is a fundamental component in the MRAC design and stability analysis. An enhanced MRC algorithm, which has been developed for systems with more controls than regulated outputs, alleviates the MRC stability constraint of stable plant transmission zeroes. The nonlinear power plant model is based on the Cromby model with the addition of a governor valve management algorithm, turbine dynamics and turbine interactions with extraction flows. An application of the MRC algorithm to a linearization of this model demonstrates its applicability to power plant systems. In particular, the generated power changes at 7% per minute while throttle pressure and temperature, reheat temperature and drum level are held constant with a reasonable level of control. The enhanced algorithm reduces significantly control fluctuations without modifying the output response.
Hay, Jessica F.; Sato, Momoko; Coren, Amy E.; Diehl, Randy L.
2002-05-01
According to Lindbloms Theory of Adaptive Dispersion (TAD), the aim of talkers is to make phonological contrasts sufficiently distinctive to promote linguistic comprehension by the listener while minimizing the articulatory effort needed to achieve this degree of distinctiveness. When part of an utterance carries new-rather than given-information, it tends to be spoken with greater emphasis and clarity. In this study, several possible acoustic correlates of vowels in emphasized words were examined in American English, French, and Japanese in comparable phonetic and sentence contexts. These possible correlates include an expanded vowel space, greater vowel inherent spectral change, and a greater systematic variation in vowel length. Preliminary analyses suggest that the contrast-enhancing properties of emphasized vowels vary considerably across languages. [Work supported by NIDCD.
Directory of Open Access Journals (Sweden)
Beatrice I. Crona
2012-03-01
Full Text Available Humanity faces increasingly intractable environmental problems characterized by high uncertainty, complexity, and swift change. Natural resource governance must therefore involve continuous production and use of new knowledge to adapt to highly complex, rapidly changing social-ecological systems to ensure long-term sustainable development. Bridging and boundary organizations have been proposed as potentially powerful means of achieving these aims by promoting cooperation among actors from the science, policy, and management sectors. However, despite substantial investments of time, capital, and human resources, little agreement exists about definitions and measures of knowledge production and how this is achieved in bridging organizations and there is only meager understanding of how knowledge production and its use are shaped by social interactions, socio-political environments, and power relations. New concepts, methods, and metrics for conceptualizing and measuring learning in support of natural resource governance and testing the conditions under which it can be achieved are therefore badly needed. This paper presents an attempt at a holistic framework to address this, drawing on theory, methods, and metrics from three research areas: knowledge utilization, boundary organizations, and stakeholder theory. Taken together, these provide a solid conceptual and methodological toolkit for conducting cross-case comparisons aimed at understanding the social environmental conditions under which learning in such organizations does and does not occur. We use empirical data to show how the framework can be applied and discuss some of the practical considerations and important challenges that emerge. We close with a general discussion and an agenda for future research to promote discussion around the topic of how to erect systematic comparisons of learning in support of adaptive natural resource governance as it occurs in bridging organizations.
Helgeson, Vicki S; Reynolds, Kerry A; Siminerio, Linda M; Becker, Dorothy J; Escobar, Oscar
2014-12-01
The purpose of the study was to determine whether resilience, defined by cognitive adaptation theory, predicted emerging adulthood outcomes among youth with and without type 1 diabetes. Youth with (n=118) and without type 1 diabetes (n=122), who were part of a previous longitudinal study during adolescence, completed on-line questionnaires during their senior year of high school and one and two years later. They were average age 18, 53% female, and 93% white. Questionnaires assessed cognitive adaptation theory (CAT) indicators (self-esteem, mastery, optimism) and psychological, relationship, behavioral, vocational, and, for those with diabetes, diabetes outcomes. The CAT index at baseline predicted reduced psychological distress, enhanced psychological well-being, increased friend support, reduced friend conflict, the presence of romantic relationships, reduced likelihood of romantic breakups, higher GPA, higher work satisfaction, and lower work stress during the transition to emerging adulthood. Among those with diabetes, the CAT index predicted better self-care behavior and revealed a marginal relation to better glycemic control. Analyses controlled for baseline levels when appropriate. Findings were stronger one year than two years post high school graduation, and findings were stronger for those with than without diabetes. Youth with diabetes also scored lower on the CAT index than youth without diabetes. These findings suggest that the implications of CAT include not only psychological health but also relationship, vocational, and diabetes outcomes. Those who score lower on CAT indicators should be identified as children so that interventions designed to enhance resilience can be implemented. Copyright © 2014 Elsevier Inc. All rights reserved.
Williams, Ffrancon
2009-01-01
, and other small molecules. Even more surprisingly, given the book's emphasis on solid-state applications, there is hardly any mention of the considerable body of work on radiation damage to biological molecules such as DNA. Chapters 10 through 13 cover Relaxation Times, Noncontinuous Excitation, Double Resonance Techniques, and Other Topics, respectively. New sections include those on Longitudinal Detection (10.6), Dynamic Nuclear Polarization (10.9), Bio-Oxygen Measurements (10.10), and Spin Coherence and Correlation (11.8). As before, chapter 13 lists comprehensive sets of literature references on a wide variety of 17 EPR-related topics, new additions being the introductory three-line Apologia (13.1) and almost three pages on Geologic/Mineralogic Systems and Selected Gems (13.10), the latter perhaps reflecting the particular interests of the senior author in EPR studies of minerals. Nine appendices (A through I) round out the book and these cover a wide range of background reference material. Discussions of mathematical operations (A) and quantum mechanics (B) are followed by an exact solution of the energy eigenvalues as well as the derivation of selection rules for the transitions of the hydrogen atom and related species (C). Appendix D is new and deals with the physical properties and magnetic resonance aspects of photons. This is followed by discussions of instrumentation (E) and experimental considerations (F). Finally, there are listings of the main EPR-related books and chapters (G); fundamental constants, conversion factors, and tables of atomic hyperfine constants (H); and a comprehensive 11-page glossary of symbols (I). Altogether these appendices provide an invaluable summary of the theoretical foundations of EPR as well as a mine of readily accessible information and key data. On the back cover, the authors claim to have brought this popular text up to date and that it provides a basic understanding of the underlying theory, fundamentals, and
Harrison, Peter M C; Collins, Tom; Müllensiefen, Daniel
2017-06-15
Modern psychometric theory provides many useful tools for ability testing, such as item response theory, computerised adaptive testing, and automatic item generation. However, these techniques have yet to be integrated into mainstream psychological practice. This is unfortunate, because modern psychometric techniques can bring many benefits, including sophisticated reliability measures, improved construct validity, avoidance of exposure effects, and improved efficiency. In the present research we therefore use these techniques to develop a new test of a well-studied psychological capacity: melodic discrimination, the ability to detect differences between melodies. We calibrate and validate this test in a series of studies. Studies 1 and 2 respectively calibrate and validate an initial test version, while Studies 3 and 4 calibrate and validate an updated test version incorporating additional easy items. The results support the new test's viability, with evidence for strong reliability and construct validity. We discuss how these modern psychometric techniques may also be profitably applied to other areas of music psychology and psychological science in general.
Nakajima, Toshiyuki
2015-12-01
Higher animals act in the world using their external reality models to cope with the uncertain environment. Organisms that have not developed such information-processing organs may also have external reality models built in the form of their biochemical, physiological, and behavioral structures, acquired by natural selection through successful models constructed internally. Organisms subject to illusions would fail to survive in the material universe. How can organisms, or living systems in general, determine the external reality from within? This paper starts with a phenomenological model, in which the self constitutes a reality model developed through the mental processing of phenomena. Then, the it-from-bit concept is formalized using a simple mathematical model. For this formalization, my previous work on an algorithmic process is employed to constitute symbols referring to the external reality, called the inverse causality, with additional improvements to the previous work. Finally, as an extension of this model, the cognizers system model is employed to describe the self as one of many material entities in a world, each of which acts as a subject by responding to the surrounding entities. This model is used to propose a conceptual framework of information theory that can deal with both the qualitative (semantic) and quantitative aspects of the information involved in biological processes. Copyright © 2015 Elsevier Ltd. All rights reserved.
Application and adaptation of Symphonology Bioethical Theory (SBT in pastoral care practice
Directory of Open Access Journals (Sweden)
M.M. Khechane
2008-01-01
Full Text Available In an environment which is ethically and from a human rights point of view overly sensitive and in which interculturism is becoming more and more a norm, pastoral care practitioners need to be committed to providing services that are ethical, intercultural and respecting of patients’ rights. This article demonstrates how application of the Symphonology Bioethical Theory (SBT as the framework for practice in pastoral care and counselling can help Pastoral Care Practitioners (PCP to be ethical while upholding patients’ human rights, and it can also help to bridge the intercultural chasm while simultaneously explaining the rationale for the practice. Symphonology is a context-driven, ethical decision- making model guiding holistic interaction between patients and PCPs. The Symphonological decision-making matrix is based on a practitioner-patient agreement for pastoral care that emphasizes patient preferences, pastoral psychological and theological knowledge, the pastoral care content and the context of the situation. The goal of the PCP is to ethically incarnate the divine presence and thus to bring about hope and emancipation to the patient using the bioethical standards of autonomy, freedom, objectivity, self-assertion, benevolence and fidelity.
Tranquille, C A; Parkin, T D H; Murray, R C
2012-11-01
Lateral condylar (LC) fractures of the third metacarpus (McIII) are a common reason for euthanasia in racehorses, and may be the result of repetitive overloading or cumulative pathological change. Magnetic resonance imaging (MRI) allows monitoring of bone and cartilage to detect pathological and adaptive changes that may be precursors of fracture. To describe bone and cartilage MRI features in the distal condyles of McIII of Thoroughbred racehorses, with and without condylar fracture. 1) A greater degree of bone and cartilage adaptation or pathology will be seen in fractured McIIIs compared with their respective contralateral McIIIs. 2) Contralateral McIIIs will have a greater degree of bone and cartilage adaptation or pathology than McIIIs from control horses that did not sustain a LC fracture. The McIIIs from 96 horses subjected to euthanasia at racecourses were divided into 3 groups: Group 1: nonfractured bones from horses without LC fracture; Group 2: nonfractured bones from horses with unilateral LC fracture; and Group 3: fractured bones from horses with unilateral LC fracture. The MR images were examined and graded for bone and cartilage changes. Nine percent of Group 1 (n = 9) and 11% of Group 2 bones (n = 5) had incomplete LC fractures. Focal palmar necrosis was most frequently detected in bones from Group 1 (12%) compared with Groups 2 (9%) and 3 (4%). The prevalence of bone and/or cartilage abnormalities tended to increase from Group 1 to Group 2 to Group 3. Magnetic resonance imaging is able to detect cartilage and bone changes that may be associated with LC fracture. There was no significant difference in bone/cartilage changes between bones from Groups 1 and 2, despite increased pathology in Group 2 bones. Periodic monitoring of bone and/or cartilage changes in distal McIII of Thoroughbred racehorses may help to prevent catastrophic LC fractures. © 2012 EVJ Ltd.
Li, Yi
It is of great scientific significance to study the complex systems of agents with adaptive strategies competing for resources. In many of such systems in social and biological environments, agents succeed by making innovative choices. In this thesis, we model this behavior by presenting the results and analysis of a class of games in which heterogeneous agents are rewarded for being in a minority group. Each agent possesses a number of fixed strategies, each of which takes publicly available information as input to predict next group. Commonly known as the minority game, this simple model manifests a maladaptive, informationally efficient phase in which the system performs poorly at generating resources and an inefficient phase in which there is an emergent cooperation among the agents, and the system more effectively generates resources. The best emergent coordination is achieved at the phase transition, which occurs when z, the ratio of the dimension of the strategy space to the number of agents, is about 0.34. This model also has similar properties to a spin glass system thus statistical mechanics methods were employed to provide analytical results. The phase structure persists under variations such as variable payoff schemes and evolutionary mechanisms. Agents in real life are subject to local connectivity and incomplete information. A framework based on bi-graph was proposed to model these factors. In the context of economics, we proposed a stock market model incorporating delayed majority dynamics and agents holding heterogeneous expectations. We found that for a range of parameter settings, minority dynamics are dynamically induced, effectively reducing market volatility. Finally, we introduce a version of the minority game played by human participants. We observed emergent coordination of players' choices leading to increased average reward. Furthermore, players with the simplest strategies reap the most wealth.
Fahleson, Tobias; Norman, Patrick
2017-10-14
The second-order nonlinear (or cubic) response function is derived from the Ehrenfest theorem with inclusion made of the finite lifetimes of the excited states, representing the extension of the derivation of the quadratic response function in the same framework [P. Norman et al., J. Chem. Phys. 123, 194103 (2005)]. The resulting damped response functions are physically sound and converging also in near-resonance and resonance regions of the spectrum. Being an accurate approximation for small complex frequencies (defined as the sum of an optical frequency and an imaginary damping parameter), the polynomial expansion of the complex cubic response function in terms of the said frequencies is presented and used to validate the program implementation. In terms of approximate state theory, the computationally tractable expressions of the damped cubic response function are derived and implemented at the levels of Hartree-Fock and Kohn-Sham density functional theory. Numerical examples are provided in terms of studies of the intensity-dependent refractive index of para-nitroaniline and the two-photon absorption cross section of neon. For the latter property, a numerical comparison is made against calculations of the square of two-photon matrix elements that are identified from a residue analysis of the resonance-divergent quadratic response function.
Lin, Jenny J; Mann, Devin M
2012-09-01
Diabetes incidence is increasing worldwide and providers often do not feel they can effectively counsel about preventive lifestyle changes. The goal of this paper is to describe the development and initial feasibility testing of the Avoiding Diabetes Thru Action Plan Targeting (ADAPT) program to enhance counseling about behavior change for patients with pre-diabetes. Primary care providers and patients were interviewed about their perspectives on lifestyle changes to prevent diabetes. A multidisciplinary design team incorporated this data to translate elements from behavior change theories to create the ADAPT program. The ADAPT program was pilot tested to evaluate feasibility. Leveraging elements from health behavior theories and persuasion literature, the ADAPT program comprises a shared goal-setting module, implementation intentions exercise, and tailored reminders to encourage behavior change. Feasibility data demonstrate that patients were able to use the program to achieve their behavior change goals. Initial findings show that the ADAPT program is feasible for helping improve primary care providers' counseling for behavior change in patients with pre-diabetes. If successful, the ADAPT program may represent an adaptable and scalable behavior change tool for providers to encourage lifestyle changes to prevent diabetes. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.
Strauss, Y
2004-01-01
A quantum mechanical version of the Lax-Phillips scattering theory was recently developed. This theory is a natural framework for the description of quantum unstable systems. However, since the spectrum of the generator of evoltuion in this theory is unbounded from below, the existsing framework does not apply to a large class of quantum mechanical problems. It is shown in this work that the fundamental mathematical structure underlying the Lax-Phillips theory, i.e., the Sz.-Nagy-Foias theory of contraction operators on Hilbert space, can be used for the construction of a formalism in which models associated with semiblounded spectrum may be accomodated.
Milne, Bruce F; Norman, Patrick
2015-05-28
The first-order hyperpolarizability, β, has been calculated for a group of marine natural products, the makaluvamines. These compounds possess a common cationic pyrroloiminoquinone structure that is substituted to varying degrees. Calculations at the MP2 level indicate that makaluvamines possessing phenolic side chains conjugated with the pyrroloiminoquinone moiety display large β values, while breaking this conjugation leads to a dramatic decrease in the calculated hyperpolarizability. This is consistent with a charge-transfer donor-π-acceptor (D-π-A) structure type, characteristic of nonlinear optical chromophores. Dynamic hyperpolarizabilities calculated using resonance-convergent time-dependent density functional theory coupled to polarizable continuum model (PCM) solvation suggest that significant resonance enhancement effects can be expected for incident radiation with wavelengths around 800 nm. The results of the current work suggest that the pyrroloiminoquinone moiety represents a potentially useful new chromophore subunit, in particular for the development of molecular probes for biological imaging. The introduction of solvent-solute interactions in the theory is conventionally made in a density matrix formalism, and the present work will provide detailed account of the approximations that need to be introduced in wave function theory and our program implementation. The program implementation as such is achieved by a mere combination of existing modules from previous developments, and it is here only briefly reviewed.
Li, Zhendong; Liu, Wenjian
2011-11-21
The recently proposed spin-adapted time-dependent density functional theory (S-TD-DFT) [Z. Li and W. Liu, J. Chem. Phys. 133, 064106 (2010)] resolves the spin-contamination problem in describing singly excited states of high spin open-shell systems. It is an extension of the standard restricted open-shell Kohn-Sham-based TD-DFT which can only access those excited states due to singlet-coupled single excitations. It is also far superior over the unrestricted Kohn-Sham-based TD-DFT (U-TD-DFT) which suffers from severe spin contamination for those excited states due to triplet-coupled single excitations. Nonetheless, the accuracy of S-TD-DFT for high spin open-shell systems is still inferior to TD-DFT for well-behaved closed-shell systems. The reason can be traced back to the violation of the spin degeneracy conditions (SDC) by approximate exchange-correlation (XC) functionals. Noticing that spin-adapted random phase approximation (S-RPA) can indeed maintain the SDC by virtue of the Wigner-Eckart theorem, a hybrid ansatz combining the good of S-TD-DFT and S-RPA can immediately be envisaged. The resulting formalism, dubbed as X-TD-DFT, is free of spin contamination and can also be viewed as a S-RPA correction to the XC kernel of U-TD-DFT. Compared with S-TD-DFT, X-TD-DFT leads to much improved results for the low-lying excited states of, e.g., N(2)(+), yet with much reduced computational cost. Therefore, X-TD-DFT can be recommended for routine calculations of excited states of high spin open-shell systems.
Energy Technology Data Exchange (ETDEWEB)
Cao, Jinjia; Gong, Xueyu; Xiang, Dong; Huang, Qianhong [School of Nuclear Science and Technology, University of South China, Hengyang 421001 (China); Wang, Aike [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China); Yu, Jun [School of Mathematics and Physics, University of South China, Hengyang 421001 (China)
2016-01-15
The enhanced transport of passing energetic ions (PEIs) in presence of the resonant interactions with a rotating magnetic island is investigated within the drift kinetic framework. When the island rotation plays a role in the resonant interaction, we find that the velocities of PEIs satisfy a constraint relation of resonant flux surface in phase space. The resonant flux surfaces overlap with the magnetic flux surfaces in real space. A new transport channel responsible for the PEIs moving across the magnetic flux surfaces, i.e., continuously overlapping, is found. Two kinds of radial motions can be induced by the surface overlapping: one arises from the coupling between the resonance and the collision with the background plasma and the other from not completely overlapping of the two surfaces. The two radial motions and the symmetry-breaking induced radial motion constitute the total radial motion. When the pitch-angle scattering rate is very weak, the surface-shear induced transport is dominant. Only a small increase in the collision rate can significantly influence the total transport.
Chai, Runqi; Savvaris, Al; Tsourdos, Antonios; Chai, Senchun
2017-07-01
Highly constrained trajectory optimization for Space Manoeuvre Vehicles (SMV) is a challenging problem. In practice, this problem becomes more difficult when multiple mission requirements are taken into account. Because of the nonlinearity in the dynamic model and even the objectives, it is usually hard for designers to generate a compromised trajectory without violating strict path and box constraints. In this paper, a new multi-objective SMV optimal control model is formulated and parameterized using combined shooting-collocation technique. A modified game theory approach, coupled with an adaptive differential evolution algorithm, is designed in order to generate the pareto front of the multi-objective trajectory optimization problem. In addition, to improve the quality of obtained solutions, a control logic is embedded in the framework of the proposed approach. Several existing multi-objective evolutionary algorithms are studied and compared with the proposed method. Simulation results indicate that without driving the solution out of the feasible region, the proposed method can perform better in terms of convergence ability and convergence speed than its counterparts. Moreover, the quality of the pareto set generated using the proposed method is higher than other multi-objective evolutionary algorithms, which means the newly proposed algorithm is more attractive for solving multi-criteria SMV trajectory planning problem.
Directory of Open Access Journals (Sweden)
Piotr Matczak
2017-01-01
Full Text Available The present work starts with providing a description of the halogen bonding (XB interaction between the halogen atom of MH3X (where M = C–Pb and X = I, At and the N atom of HCN. This interaction leads to the formation of stable yet very weakly bound MH3X⋯NCH complexes for which the interaction energy (Eint between MH3X and HCN is calculated using various symmetry-adapted perturbation theory (SAPT methods combined with the def2-QZVPP basis set and midbond functions. This basis set assigns effective core potentials (ECPs not only to the I or At atom directly participating in the XB interaction with HCN but also to the M atom when substituted with Sn or Pb. Twelve SAPT methods (or levels are taken into consideration. According to the SAPT analysis of Eint, the XB interaction in the complexes shows mixed electrostatic-dispersion nature. Next, the accuracy of SAPT Eint is evaluated by comparing with CCSD(T reference data. This comparison reveals that high-order SAPT2+(3 method and the much less computationally demanding SAPT(DFT method perform very well in describing Eint of the complexes. However, the accuracy of these methods decreases dramatically if they are combined with the so-called Hartree-Fock correction.
Cox, D N; Koster, A; Russell, C G
2004-08-01
The widespread use of dietary supplements and so-called 'functional foods' is thought to be partially motivated by self-control of health. However, whilst consumers want foods associated with well-being or disease prevention, they are unlikely to be willing to compromise on taste or technology. This presents a dilemma for promoters of functional foods. Middle-aged consumers' intentions to consume functional foods or supplements that may improve memory were tested within an adaptation of Protection Motivation theory (PMT). Participants evaluated text descriptions of four products described as: having an unpleasant bitter taste (Natural-FF); having 'additives' to reduce bitterness (Sweetened-FF); being genetically modified to enhance function (GM-FF) and Supplements. Participants were recruited as being of high and low perceived vulnerability to memory failure. In total, 290 middle-aged consumers (aged 40-60 years) participated in the study. Motivations to consume the GM-FF were the lowest. There were gender differences between intention to consume the supplements, Natural-FF and Sweetened-FF and product differences within genders. Women were less favourable than men in their attitudes towards genetic modification in general. Regression analyses indicated that PM predictors of intention to consume functional foods or supplements explained 59-63% of the variance (R2). Overall, perceived 'efficacy' (of the behaviour) and self-efficacy were the most important predictors of intentions to consume.
Rapp, Alexander M.; Leube, Dirk T.; Erb, Michael; Grodd, Wolfgang; Kircher, Tilo T. J.
2007-01-01
We investigated processing of metaphoric sentences using event-related functional magnetic resonance imaging (fMRI). Seventeen healthy subjects (6 female, 11 male) read 60 novel short German sentence pairs with either metaphoric or literal meaning and performed two different tasks: judging the metaphoric content and judging whether the sentence…
DEFF Research Database (Denmark)
Brooks, Anthony Lewis
2013-01-01
tailored channeling of sensory stimulus aligned as ‘art-making’ and ‘game playing’ core experiences. Thus, affecting brain plasticity and human motoric-performance via the adaptability (plasticity) of digital medias result in closure of the human afferent-efferent neural feedback loop closure through...... the unencumbered motion-to-computer-generated activities - ‘Music Making’, ‘Painting’, ‘Robotic’ and ‘Video Game’ control. A focus of this position paper is to highlight how Aesthetic Resonance, in this context, relates to the growing body of research on Neuroaesthetics to evolve Neuroaesthetic Resonance....
1982-02-01
associations. These associations may be S-S, R-R, or S-R. The associations are contextually bound in some broad sense so that we might think of "work...ACTIONS OF OTHERS t ’oaPe rtin LEARNING THROUGH CLASSES OF ENVIRONMENTAL INTERACTIONS Reasoning LEARNING THROUGH INDIVIDUAL ENVIROMENTAL INTERACTIONS...Dorsev, 1968. Ryan, T. A. Recollecting, imagining, and thinking . in E. G. Boring, H. S. Langfeld, & H. P. Weld (Eds.), Foundations of psychology. New
International Nuclear Information System (INIS)
Cisneros S, A.; McIntosh, H.V.
1982-01-01
A discussion of the nature of quantum mechanical resonances is presented from the point of view of the spectral theory of operators. In the case of Bohr-Feshbach resonances, graphs are presented to illustrate the theory showing the decay of a doubly excited metastable state and the excitation of the resonance by an incident particle with proper energy. A characterization of resonances is given as well as a procedure to determine widths using the spectral density function. A sufficient condition is given for the validity of the Breit-Wigner formula for Bohr-Feshbach resonances. (author)
Energy Technology Data Exchange (ETDEWEB)
Journel, Loiec; El Khoury, Lara; Marin, Thierry; Guillemin, Renaud; Carniato, Stephane; Avila, Antoine; Delaunay, Renaud; Hague, Coryn F.; Simon, Marc [Laboratoire de Chimie Physique-Matiere et Rayonnement, UPMC University of Paris 06, UMR 7614, F-75005 Paris (France) and Laboratoire de Chimie Physique-Matiere et Rayonnement, CNRS, UMR 7614, F-75005 Paris (France)
2009-09-15
We describe a bent-crystal spectrometer adapted to measure x-ray emission resulting from core-level excitation of gas-phase molecules in the 0.8-8 keV energy range. The spectrometer is based on the Johann principle, and uses a microfocused photon beam to provide high-resolution (resolving power of {approx}7500). A gas cell was designed to hold a high-pressure (300 mbar) sample of gas while maintaining a high vacuum (10{sup -9} mbar) in the chamber. The cell was designed to optimize the counting rate (2000 cts/s at the maximum of the Cl K{alpha} emission line), while minimizing self-absorption. Example of the K{alpha} emission lines of CH{sub 3}Cl molecules is presented to illustrate the capabilities of this new instrument.
Bhatia, A. K.
2012-01-01
The P-wave hybrid theory of electron-hydrogen elastic scattering [Phys. Rev. A 85, 052708 (2012)] is applied to the P-wave scattering from He ion. In this method, both short-range and long-range correlations are included in the Schroedinger equation at the same time, by using a combination of a modified method of polarized orbitals and the optical potential formalism. The short-correlation functions are of Hylleraas type. It is found that the phase shifts are not significantly affected by the modification of the target function by a method similar to the method of polarized orbitals and they are close to the phase shifts calculated earlier by Bhatia [Phys. Rev. A 69, 032714 (2004)]. This indicates that the correlation function is general enough to include the target distortion (polarization) in the presence of the incident electron. The important fact is that in the present calculation, to obtain similar results only a 20-term correlation function is needed in the wave function compared to the 220- term wave function required in the above-mentioned calculation. Results for the phase shifts, obtained in the present hybrid formalism, are rigorous lower bounds to the exact phase shifts. The lowest P-wave resonances in He atom and hydrogen ion have been calculated and compared with the results obtained using the Feshbach projection operator formalism [Phys. Rev. A, 11, 2018 (1975)]. It is concluded that accurate resonance parameters can be obtained by the present method, which has the advantage of including corrections due to neighboring resonances, bound states and the continuum in which these resonance are embedded.
Landis-Lewis, Zach; Brehaut, Jamie C; Hochheiser, Harry; Douglas, Gerald P; Jacobson, Rebecca S
2015-01-21
Evidence shows that clinical audit and feedback can significantly improve compliance with desired practice, but it is unclear when and how it is effective. Audit and feedback is likely to be more effective when feedback messages can influence barriers to behavior change, but barriers to change differ across individual health-care providers, stemming from differences in providers' individual characteristics. The purpose of this article is to invite debate and direct research attention towards a novel audit and feedback component that could enable interventions to adapt to barriers to behavior change for individual health-care providers: computer-supported tailoring of feedback messages. We argue that, by leveraging available clinical data, theory-informed knowledge about behavior change, and the knowledge of clinical supervisors or peers who deliver feedback messages, a software application that supports feedback message tailoring could improve feedback message relevance for barriers to behavior change, thereby increasing the effectiveness of audit and feedback interventions. We describe a prototype system that supports the provision of tailored feedback messages by generating a menu of graphical and textual messages with associated descriptions of targeted barriers to behavior change. Supervisors could use the menu to select messages based on their awareness of each feedback recipient's specific barriers to behavior change. We anticipate that such a system, if designed appropriately, could guide supervisors towards giving more effective feedback for health-care providers. A foundation of evidence and knowledge in related health research domains supports the development of feedback message tailoring systems for clinical audit and feedback. Creating and evaluating computer-supported feedback tailoring tools is a promising approach to improving the effectiveness of clinical audit and feedback.
Jones, Catherine M; Clavier, Carole; Potvin, Louise
2017-03-01
National policies on global health appear as one way that actors from health, development and foreign affairs sectors in a country coordinate state action on global health. Next to a burgeoning literature in which international relations and global governance theories are employed to understand global health policy and global health diplomacy at the international level, little is known about policy processes for global health at the national scale. We propose a framework of the policy process to understand how such policies are developed, and we identify challenges for public health researchers integrating conceptual tools from political science. We developed the framework using a two-step process: 1) reviewing literature to establish criteria for selecting a theoretical framework fit for this purpose, and 2) adapting Real-Dato's synthesis framework to integrate a cognitive approach to public policy within a constructivist perspective. Our framework identifies multiple contexts as part of the policy process, focuses on situations where actors work together to make national policy on global health, considers these interactive situations as spaces for observing external influences on policy change and proposes policy design as the output of the process. We suggest that this framework makes three contributions to the conceptualisation of national policy on global health as a research object. First, it emphasizes collective action over decisions of individual policy actors. Second, it conceptualises the policy process as organised interactive spaces for collaboration rather than as stages of a policy cycle. Third, national decision-making spaces are opportunities for transferring ideas and knowledge from different sectors and settings, and represent opportunities to identify international influences on a country's global health policy. We discuss two sets of challenges for public health researchers using interdisciplinary approaches in policy research. Copyright
Brooks, Anthony Lewis
2013-01-01
Neuroaesthetic Resonance emerged from a mature body of patient- centered gesture-control research investigating non-formal rehabilitation via ICT-enhanced-Art to question ‘Aesthetic Resonance’. Motivating participation, ludic engagement, and augmenting physical motion in non-formal (fun) treatment sessions are achieved via adaptive action-analyzed activities. These interactive virtual environments are designed to empower patients’ creative and/or playful expressions via digital feedback stimu...
Advances in magnetic resonance 10
Waugh, John S
2013-01-01
Advances in Magnetic Resonance, Volume 10, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains three chapters that examine superoperators in magnetic resonance; ultrasonically modulated paramagnetic resonance; and the utility of electron paramagnetic resonance (EPR) and electron-nuclear double-resonance (ENDOR) techniques for studying low-frequency modes of atomic fluctuations and their significance for understanding the mechanism of structural phase transitions in solids.
International Nuclear Information System (INIS)
Patel, Aakash B; Chakraborty, Himadri S
2011-01-01
The photoionization cross section of endohedral Xe-C 60 over a Xe 4d giant resonance energy region, calculated in the time-dependent local density approximation, is compared with recent measurements (Kilcoyne et al 2010 Phys. Rev. Lett. 105 213001). An analysis based on the Fourier transforms of oscillatory cross sections is performed to derive a number of inherent similarities between the prediction and the data, including a large beating-type oscillation and several others of intermediate size. Results stress the need for more accurate measurements to access the wealth of information about the geometry of the system. (fast track communication)
Energy Technology Data Exchange (ETDEWEB)
De Ninno, G
1999-07-01
The two parts of the thesis are a mission-oriented task devoted to solve some practical problems of the Antiproton Decelerator (AD) project at CERN, and a theoretical study leading to a new method for representing and compensating betatron resonances. The AD is a new machine (at the moment under commissioning at CERN) that will allow the collection and the deceleration of an antiproton beam from 3.5 GeV/c down to 100 MeV/c (the momentum favoured for the foreseen physics experiments). The need to employ the AD magnets over a wide range required a careful study of their characteristics. The presence of a solenoid inside the AD electron cooling device generates linear coupling between the transverse degrees of freedom of the single-particle motion. Coupling can lead to operational problems and therefore a compensation scheme had tobe designed. The long-standing problem has been solved of how to establish a relationship between the two standard methods for dealing with linear coupling: the matrix approach and the Hamiltonian approach. The bridge was built by including in the Hamiltonian approach in the high frequency part of the perturbative Hamiltonian due to coupling. The procedure was generalised to the nonlinear case and, a new method was proposed for dealing both with linear and nonlinear resonances. (author)
Alexander, Jennifer Alexandra
Lexical-tone languages use fundamental frequency (F0/pitch) to convey word meaning. About 41.8% of the world's languages use lexical tone (Maddieson, 2008), yet those systems are under-studied. I aim to increase our understanding of speech-sound inventory organization by extending to tone-systems a model of vowel-system organization, the Theory of Adaptive Dispersion (TAD) (Liljencrants and Lindblom, 1972). This is a cross-language investigation of whether and how the size of a tonal inventory affects (A) acoustic tone-space size and (B) dispersion of tone categories within the tone-space. I compared five languages with very different tone inventories: Cantonese (3 contour, 3 level tones); Mandarin (3 contour, 1 level tone); Thai (2 contour, 3 level tones); Yoruba (3 level tones only); and Igbo (2 level tones only). Six native speakers (3 female) of each language produced 18 CV syllables in isolation, with each of his/her language's tones, six times. I measured tonal F0 across the vowel at onset, midpoint, and offglide. Tone-space size was the F0 difference in semitones (ST) between each language's highest and lowest tones. Tone dispersion was the F0 distance (ST) between two tones shared by multiple languages. Following the TAD, I predicted that languages with larger tone inventories would have larger tone-spaces. Against expectations, tone-space size was fixed across level-tone languages at midpoint and offglide, and across contour-tone languages (except Thai) at offglide. However, within each language type (level-tone vs. contour-tone), languages with smaller tone inventories had larger tone spaces at onset. Tone-dispersion results were also unexpected. The Cantonese mid-level tone was further dispersed from a tonal baseline than the Yoruba mid-level tone; Cantonese mid-level tone dispersion was therefore greater than theoretically necessary. The Cantonese high-level tone was also further dispersed from baseline than the Mandarin high-level tone -- at midpoint
Hashino, Satoshi; Wada, Keiji; Shimizu, Toshihisa
Power supplies used on the electric power environment test process for electronic products and audio-amplifiers are required to generate arbitrary ac voltage waveforms in the wide frequency range. Traditionally, analogue amplifier technologies have been used for those application even though those have the disadvantages of low-efficiency, bulky in volume, and heavy in weight. Recently, however, research on the arbitrary waveform power generator becomes to be attractive among power electronics engineers, because the audio amplifiers utilizes the D-Mode switching technologies have been move into the market. This paper presents an arbitrary ac power generator utilizes a novel instantaneous waveform control method for a single-phase voltage source PWM inverter. A remarkable feature of this control method is that an adaptive frequency band-pass filter based on a rotation frame transformation and a command generator on the rotation frame is used. The proposed method can suppress the resonance caused by the LC filter at the output line, and hence it enables to generate a rectangular voltage waveform without overshoot. The command generator generates both an instantaneous frame angle and accurate voltage commands on the rotating frame from one an analogue signal. The effectiveness of this method is verified through 500W experimental set-up.
Energy Technology Data Exchange (ETDEWEB)
Dimopoulos, Johannes C.A. [Department of Radiation Oncology, Metropolitan Hospital, Athens (Greece); Schmid, Maximilian P., E-mail: maximilian.schmid@akhwien.at [Department of Radiotherapy, Medical University of Vienna, Vienna (Austria); Fidarova, Elena; Berger, Daniel; Kirisits, Christian; Poetter, Richard [Department of Radiotherapy, Medical University of Vienna, Vienna (Austria)
2012-04-01
Purpose: To investigate the clinical feasibility of magnetic resonance image-guided adaptive brachytherapy (IGABT) for patients with locally advanced vaginal cancer and to report treatment outcomes. Methods and Materials: Thirteen patients with vaginal cancer were treated with external beam radiotherapy (45-50.4 Gy) plus IGABT with or without chemotherapy. Distribution of International Federation of Gynecology and Obstetrics stages among patients were as follows: 4 patients had Stage II cancer, 5 patients had Stage III cancer, and 4 patients had Stage IV cancer. The concept of IGABT as developed for cervix cancer was transferred and adapted for vaginal cancer, with corresponding treatment planning and reporting. Doses were converted to the equivalent dose in 2 Gy, applying the linear quadratic model ({alpha}/{beta} = 10 Gy for tumor; {alpha}/{beta} = 3 for organs at risk). Endpoints studied were gross tumor volume (GTV), dose-volume parameters for high-risk clinical target volume (HRCTV), and organs at risk, local control (LC), adverse side effects, and survival. Results: The mean GTV ({+-} 1 standard deviation) at diagnosis was 45.3 ({+-}30) cm{sup 3}, and the mean GTV at brachytherapy was 10 ({+-}14) cm{sup 3}. The mean D90 for the HRCTV was 86 ({+-}13) Gy. The mean D2cc for bladder, urethra, rectum, and sigmoid colon were 80 ({+-}20) Gy, 76 ({+-}16) Gy, 70 ({+-}9) Gy, and 60 ({+-}9) Gy, respectively. After a median follow-up of 43 months (range, 19-87 months), one local recurrence and two distant metastases cases were observed. Actuarial LC and overall survival rates at 3 years were 92% and 85%. One patient with Stage IVA and 1 patient with Stage III disease experienced fistulas (one vesicovaginal, one rectovaginal), and 1 patient developed periurethral necrosis. Conclusions: The concept of IGABT, originally developed for treating cervix cancer, appears to be applicable to vaginal cancer treatment with only minor adaptations. Dose-volume parameters for HRCTV and
International Nuclear Information System (INIS)
Dimopoulos, Johannes C.A.; Schmid, Maximilian P.; Fidarova, Elena; Berger, Daniel; Kirisits, Christian; Pötter, Richard
2012-01-01
Purpose: To investigate the clinical feasibility of magnetic resonance image-guided adaptive brachytherapy (IGABT) for patients with locally advanced vaginal cancer and to report treatment outcomes. Methods and Materials: Thirteen patients with vaginal cancer were treated with external beam radiotherapy (45–50.4 Gy) plus IGABT with or without chemotherapy. Distribution of International Federation of Gynecology and Obstetrics stages among patients were as follows: 4 patients had Stage II cancer, 5 patients had Stage III cancer, and 4 patients had Stage IV cancer. The concept of IGABT as developed for cervix cancer was transferred and adapted for vaginal cancer, with corresponding treatment planning and reporting. Doses were converted to the equivalent dose in 2 Gy, applying the linear quadratic model (α/β = 10 Gy for tumor; α/β = 3 for organs at risk). Endpoints studied were gross tumor volume (GTV), dose-volume parameters for high-risk clinical target volume (HRCTV), and organs at risk, local control (LC), adverse side effects, and survival. Results: The mean GTV (± 1 standard deviation) at diagnosis was 45.3 (±30) cm 3 , and the mean GTV at brachytherapy was 10 (±14) cm 3 . The mean D90 for the HRCTV was 86 (±13) Gy. The mean D2cc for bladder, urethra, rectum, and sigmoid colon were 80 (±20) Gy, 76 (±16) Gy, 70 (±9) Gy, and 60 (±9) Gy, respectively. After a median follow-up of 43 months (range, 19–87 months), one local recurrence and two distant metastases cases were observed. Actuarial LC and overall survival rates at 3 years were 92% and 85%. One patient with Stage IVA and 1 patient with Stage III disease experienced fistulas (one vesicovaginal, one rectovaginal), and 1 patient developed periurethral necrosis. Conclusions: The concept of IGABT, originally developed for treating cervix cancer, appears to be applicable to vaginal cancer treatment with only minor adaptations. Dose-volume parameters for HRCTV and organs at risk are in a comparable
International Nuclear Information System (INIS)
Knight, D.W.
1976-01-01
Reasons are given for studying the form factor and a method for constructing all believed-to-be leading form factor diagrams in a certain class of non-Abelian gauge theories (NAGT's) in typical kinematic limits. The possibility that the form factor ''exponentiates'' in NAGT's (as it does in QED) is discussed. A method is given for constructing all 1CI planar diagrams (this is, all 1PI diagrams except those which separate upon cutting at a vertex) directly from one's heat--that is, without the need to refer to tables, et cetera. It is noted that the material is believed to be essentially completely original, that is, the technique for constructing all 1CI planar diagrams in an iterative fashion is completely new. Of course, one can construct them in an essentially random fashion, but this technique is slow and extremely error prone compared with the iterative technique given. The idea of associating an elastic resonance with a complex pole in the analytic scattering amplitude, T(E), is discussed. Calculations of the pole position and the residue of the Δ 33 resonance are given, along with an analysis of experimentally induced error in the pole position
Energy Technology Data Exchange (ETDEWEB)
Behbahani, Siavosh R.; /SLAC /Stanford U., Phys. Dept. /Boston U.; Dymarsky, Anatoly; /Princeton, Inst. Advanced Study; Mirbabayi, Mehrdad; /New York U., CCPP /New York U.; Senatore, Leonardo; /Stanford U., Phys. Dept. /KIPAC, Menlo Park
2012-06-06
We apply the Effective Field Theory of Inflation to study the case where the continuous shift symmetry of the Goldstone boson {pi} is softly broken to a discrete subgroup. This case includes and generalizes recently proposed String Theory inspired models of Inflation based on Axion Monodromy. The models we study have the property that the 2-point function oscillates as a function of the wavenumber, leading to oscillations in the CMB power spectrum. The non-linear realization of time diffeomorphisms induces some self-interactions for the Goldstone boson that lead to a peculiar non-Gaussianity whose shape oscillates as a function of the wavenumber. We find that in the regime of validity of the effective theory, the oscillatory signal contained in the n-point correlation functions, with n > 2, is smaller than the one contained in the 2-point function, implying that the signature of oscillations, if ever detected, will be easier to find first in the 2-point function, and only then in the higher order correlation functions. Still the signal contained in higher-order correlation functions, that we study here in generality, could be detected at a subleading level, providing a very compelling consistency check for an approximate discrete shift symmetry being realized during inflation.
International Nuclear Information System (INIS)
Dowling, Jason A.; Lambert, Jonathan; Parker, Joel; Salvado, Olivier; Fripp, Jurgen; Capp, Anne; Wratten, Chris; Denham, James W.; Greer, Peter B.
2012-01-01
Purpose: Prostate radiation therapy dose planning directly on magnetic resonance imaging (MRI) scans would reduce costs and uncertainties due to multimodality image registration. Adaptive planning using a combined MRI-linear accelerator approach will also require dose calculations to be performed using MRI data. The aim of this work was to develop an atlas-based method to map realistic electron densities to MRI scans for dose calculations and digitally reconstructed radiograph (DRR) generation. Methods and Materials: Whole-pelvis MRI and CT scan data were collected from 39 prostate patients. Scans from 2 patients showed significantly different anatomy from that of the remaining patient population, and these patients were excluded. A whole-pelvis MRI atlas was generated based on the manually delineated MRI scans. In addition, a conjugate electron-density atlas was generated from the coregistered computed tomography (CT)-MRI scans. Pseudo-CT scans for each patient were automatically generated by global and nonrigid registration of the MRI atlas to the patient MRI scan, followed by application of the same transformations to the electron-density atlas. Comparisons were made between organ segmentations by using the Dice similarity coefficient (DSC) and point dose calculations for 26 patients on planning CT and pseudo-CT scans. Results: The agreement between pseudo-CT and planning CT was quantified by differences in the point dose at isocenter and distance to agreement in corresponding voxels. Dose differences were found to be less than 2%. Chi-squared values indicated that the planning CT and pseudo-CT dose distributions were equivalent. No significant differences (p > 0.9) were found between CT and pseudo-CT Hounsfield units for organs of interest. Mean ± standard deviation DSC scores for the atlas-based segmentation of the pelvic bones were 0.79 ± 0.12, 0.70 ± 0.14 for the prostate, 0.64 ± 0.16 for the bladder, and 0.63 ± 0.16 for the rectum. Conclusions: The
Sánchez López, José Luis; Campoy Cervera, Pascual; Olivares Méndez, Miguel Ángel; Mellado Bataller, Ignacio; Galindo Gallego, David
2012-01-01
The objective of this paper is to design a path following control system for a car-like mobile robot using classical linear control techniques, so that it adapts on-line to varying conditions during the trajectory following task. The main advantages of the proposed control structure is that well known linear control theory can be applied in calculating the PID controllers to ful l control requirements, while at the same time it is exible to be applied in non-linear changing...
Joseph, Rachel A; Goodfellow, Linda M; Simko, Lynn C
2014-06-01
Theories provide a roadmap for scientific inquiry, help organize knowledge, and establish the foundation for knowledge development. The Double ABCX Model of Family Stress and Adaptation is a middle-range theory developed in social science and widely used by researchers of various disciplines. This model encompasses the major variables of interest in this study, including stress, coping, duration of tracheostomy, and quality-of-life, and forms an excellent framework for this specific research study. The purpose of this article was to discuss relationships between various individual and environmental factors that can impact health and well-being in families. In addition, this article illustrates how the application of the model helps nurses and healthcare providers understand the significance of the family context on positive well-being and promote optimal caring practices to achieve a balance in the midst of illness and suffering.
Carlson, Glenn Andrew
This dissertation develops details of Handel's Maser-Soliton Theory of ball lightning. The atmosphere between a thundercloud and the Earth's surface is modeled as an idealized stable open resonator with water vapor as the active medium and the thundercloud and Earth's surface as reflecting surfaces. The stable resonator generates a maser beam that narrows to the beam waist at the Earth's surface, which is assumed to be planar. Two candidate rotational transitions are identified within the ν1ν 2ν3 = 010 vibrational band of water having wavelengths of 13.9 cm and 1.12 cm, and relevant spectroscopic parameters are retrieved from the HITRAN 2008 molecular spectroscopic database. The maser is modeled as a continuously pumped four-level maser that includes the effects of nonradiative relaxation due to molecular collisions and of microwave absorption in atmospheric oxygen. Since maser spiking is highly unlikely to occur due to the high rate of collisional relaxation at normal atmospheric pressure, the electrical breakdown of air must be achieved by the steady state output of the atmospheric maser. A parametric analysis is performed to relate the size of the atmospheric maser to the pumping rate needed to create a steady state population inversion sufficient to generate maser radiation intense enough at the beam waist to result in the electrical breakdown of air. The analysis suggests that electric field intensities at the beam waist sufficient to cause electrical breakdown of air could only be created through huge pumping rates (˜105 to 107 times the critical pumping rate) and only for the most highly curved clouds (g ≈ 0) that give the narrowest beam waists.
Sudhyadhom, Atchar
2017-11-01
The accurate determination of mean ionization potential (I m) has the potential to reduce range uncertainty based margins and therefore allow for more focal treatments in proton radiotherapy. Many methods have been proposed to reduce uncertainty in I m and stopping power ratios (SPR), each with varying degrees of accuracy and issues. In this work, we present a simple parameterized model to determine I m in human biological tissue, allowing for the computation of patient-specific I m at the voxel level using magnetic resonance imaging (MRI). The model requires the measurement of three parameters by MRI, with only two parameters, mass percent water content and mass percent hydrogen content in organic molecules, required for the special case of soft tissues. The accuracy of this I m determination method was evaluated in available ‘standard’ (ICRU Report #44, (ICRU 1989 Tissue Substitutes in Radiation Dosimetry and Measurement (Bethesda, MD: International Commission on Radiation Units and Measurements))) human tissues. The sensitivity of this I m determination method to in vivo perturbations was also tested by calculating the effect of 10% variations in the experimentally measurable parameters on I m and SPR. For the human tissues modeled in this work, a high level of accuracy with low susceptibility to perturbations in measurement error was achieved in the prediction of I m. Root-mean-square errors in I m were within 0.77% and 1.8% for both soft and bony tissues, and were 0.09% and 0.2% for the SPR of soft and bony tissues, respectively, assuming knowledge of electron density. Proof of principle MR measurements and model-based computations of I m and SPR were taken in phantom for a series of hydrogenous solutions and compared against expected I m and SPR calculations from known elemental composition. MR determined I m and SPR values in a known composition solution were determined to within 5% and 0.52%, respectively. We present a novel model to accurately
Clarke, Kaila-Lea; Berry, Peter
2012-02-01
It is now recognized that climate change affects human health. The question is how to adapt. This article examines mainstreaming climate considerations into public health programs and the utility of climate change and health adaptation frameworks, using Ontario, Canada, as a case study. A literature review identified climate change and health adaptation frameworks for comparison with the Ontario Public Health Standards. Key informant interviews gauged the extent to which climate change risks are currently considered in policy and planning. Ontario's Public Health Standards already require many of the risk management activities identified in climate change and health adaptation frameworks. However, public health officials require additional information about linkages between climate change and health to manage risks. Risk management activities such as population health assessments, surveillance and public education and outreach can address many key risks related to climate hazards when information about the risks, vulnerable populations and time scales is made available to health officials. The development, analysis and transfer of this information should be considered a priority at all levels within the public health sector.
DePalma, Michael-John; Ringer, Jeffrey M.
2011-01-01
In this paper, we argue that discussions of transfer in L2 writing and composition studies have focused primarily on the reuse of past learning and thus have not adequately accounted for the adaptation of learned writing knowledge in unfamiliar situations. In an effort to expand disciplinary discussions of transfer in L2 writing and composition…
Zhang, Gaigong; Lin, Lin; Hu, Wei; Yang, Chao; Pask, John E.
2017-04-01
Recently, we have proposed the adaptive local basis set for electronic structure calculations based on Kohn-Sham density functional theory in a pseudopotential framework. The adaptive local basis set is efficient and systematically improvable for total energy calculations. In this paper, we present the calculation of atomic forces, which can be used for a range of applications such as geometry optimization and molecular dynamics simulation. We demonstrate that, under mild assumptions, the computation of atomic forces can scale nearly linearly with the number of atoms in the system using the adaptive local basis set. We quantify the accuracy of the Hellmann-Feynman forces for a range of physical systems, benchmarked against converged planewave calculations, and find that the adaptive local basis set is efficient for both force and energy calculations, requiring at most a few tens of basis functions per atom to attain accuracies required in practice. Since the adaptive local basis set has implicit dependence on atomic positions, Pulay forces are in general nonzero. However, we find that the Pulay force is numerically small and systematically decreasing with increasing basis completeness, so that the Hellmann-Feynman force is sufficient for basis sizes of a few tens of basis functions per atom. We verify the accuracy of the computed forces in static calculations of quasi-1D and 3D disordered Si systems, vibration calculation of a quasi-1D Si system, and molecular dynamics calculations of H2 and liquid Al-Si alloy systems, where we show systematic convergence to benchmark planewave results and results from the literature.
McGill, Anne-Thea
2014-01-01
Metabolic syndrome (MetS) predicts type II diabetes mellitus (TIIDM), cardiovascular disease (CVD) and cancer, and their rates have escalated over the last few decades. Obesity related co-morbidities also overlap the concept of the metabolic syndrome (MetS). However, understanding of the syndrome's underlying causes may have been misapprehended. The current paper follows on from a theory review by McGill, A-T in Archives of Public Health, 72: 30. This accompanying paper utilises research on human evolution and new biochemistry to theorise on why MetS and obesity arise and how they affect the population. The basis of this composite unifying theory is that the proportionately large, energy-demanding human brain may have driven co-adaptive mechanisms to provide, or conserve, energy for the brain. A 'dual system' is proposed. 1) The enlarged, complex cortico-limbic-striatal system increases dietary energy by developing strong neural self-reward/motivation pathways for the acquisition of energy dense food, and (2) the nuclear factor-erythroid 2-related factor 2 (NRF2) cellular protection system amplifies antioxidant, antitoxicant and repair activity by employing plant chemicals. In humans who consume a nutritious diet, the NRF2 system has become highly energy efficient. Other relevant human-specific co-adaptations are explored. In order to 'test' this composite unifying theory it is important to show that the hypothesis and sub-theories pertain throughout the whole of human evolution and history up till the current era. Corollaries of the composite unifying theory of MetS are examined with respect to past under-nutrition and malnutrition since agriculture began 10,000 years ago. The effects of man-made pollutants on degenerative change are examined. Projections are then made from current to future patterns on the state of 'insufficient micronutrient and/or unbalanced high energy malnutrition with central obesity and metabolic dysregulation' or 'malnubesity'. Forecasts
Ghobadi, Ahmadreza F.; Elliott, J. Richard
2013-12-01
In this work, we aim to develop a version of the Statistical Associating Fluid Theory (SAFT)-γ equation of state (EOS) that is compatible with united-atom force fields, rather than experimental data. We rely on the accuracy of the force fields to provide the relation to experimental data. Although, our objective is a transferable theory of interfacial properties for soft and fused heteronuclear chains, we first clarify the details of the SAFT-γ approach in terms of site-based simulations for homogeneous fluids. We show that a direct comparison of Helmholtz free energy to molecular simulation, in the framework of a third order Weeks-Chandler-Andersen perturbation theory, leads to an EOS that takes force field parameters as input and reproduces simulation results for Vapor-Liquid Equilibria (VLE) calculations. For example, saturated liquid density and vapor pressure of n-alkanes ranging from methane to dodecane deviate from those of the Transferable Potential for Phase Equilibria (TraPPE) force field by about 0.8% and 4%, respectively. Similar agreement between simulation and theory is obtained for critical properties and second virial coefficient. The EOS also reproduces simulation data of mixtures with about 5% deviation in bubble point pressure. Extension to inhomogeneous systems and united-atom site types beyond those used in description of n-alkanes will be addressed in succeeding papers.
Ruel, Hubertus Johannes Maria; Chiemeke, Charles C.; Bondarouk, Tatiana; Ruel, Hubertus Johannes Maria; Guiderdoni-Jourdain, Karine; Oiry, Ewan
2009-01-01
Research on Human Resource Information Systems (HRIS) implementation lacks theoretical depth and richness. For that reason this paper applies a theory to HRIS implementation developed by Gerardine DeSanctis and Marshal Scott Poole originally for studying information systems implementation, namely
Perspective on resonances of metamaterials.
Min, Li; Huang, Lirong
2015-07-27
Electromagnetic resonance as the most important characteristic of metamaterials enables lots of exotic phenomena, such as invisible, negative refraction, man-made magnetism, etc. Conventional LC-resonance circuit model as the most authoritative and classic model is good at explaining and predicting the fundamental resonance wavelength of a metamaterial, while feels hard for high-order resonances, especially for resonance intensity (strength of resonance, determining on the performance and efficiency of metamaterial-based devices). In present work, via an easy-to-understand mass-spring model, we present a different and comprehensive insight for the resonance mechanism of metamaterials, through which both the resonance wavelengths (including the fundamental and high-order resonance wavelengths) and resonance intensities of metamaterials can be better understood. This developed theory has been well verified by different-material and different-structure resonators. This perspective will provide a broader space for exploring novel optical devices based on metamaterials (or metasurfaces).
International Nuclear Information System (INIS)
Carr, J. K.; Roy, S.; Skinner, J. L.; Zabuga, A. V.; Rizzo, T. R.
2014-01-01
The spectroscopy of amide I vibrations has become a powerful tool for exploring protein structure and dynamics. To help with spectral interpretation, it is often useful to perform molecular dynamics (MD) simulations. To connect spectroscopic experiments to simulations in an efficient manner, several researchers have proposed “maps,” which relate observables in classical MD simulations to quantum spectroscopic variables. It can be difficult to discern whether errors in the theoretical results (compared to experiment) arise from inaccuracies in the MD trajectories or in the maps themselves. In this work, we evaluate spectroscopic maps independently from MD simulations by comparing experimental and theoretical spectra for a single conformation of the α-helical model peptide Ac-Phe-(Ala) 5 -Lys-H + in the gas phase. Conformation-specific experimental spectra are obtained for the unlabeled peptide and for several singly and doubly 13 C-labeled variants using infrared-ultraviolet double-resonance spectroscopy, and these spectra are found to be well-modeled by density functional theory (DFT) calculations at the B3LYP/6-31G** level. We then compare DFT results for the deuterated and 13 C 18 O-labeled peptide with those from spectroscopic maps developed and used previously by the Skinner group. We find that the maps are typically accurate to within a few cm −1 for both frequencies and couplings, having larger errors only for the frequencies of terminal amides
Carr, J K; Zabuga, A V; Roy, S; Rizzo, T R; Skinner, J L
2014-06-14
The spectroscopy of amide I vibrations has become a powerful tool for exploring protein structure and dynamics. To help with spectral interpretation, it is often useful to perform molecular dynamics (MD) simulations. To connect spectroscopic experiments to simulations in an efficient manner, several researchers have proposed "maps," which relate observables in classical MD simulations to quantum spectroscopic variables. It can be difficult to discern whether errors in the theoretical results (compared to experiment) arise from inaccuracies in the MD trajectories or in the maps themselves. In this work, we evaluate spectroscopic maps independently from MD simulations by comparing experimental and theoretical spectra for a single conformation of the α-helical model peptide Ac-Phe-(Ala)5-Lys-H(+) in the gas phase. Conformation-specific experimental spectra are obtained for the unlabeled peptide and for several singly and doubly (13)C-labeled variants using infrared-ultraviolet double-resonance spectroscopy, and these spectra are found to be well-modeled by density functional theory (DFT) calculations at the B3LYP/6-31G** level. We then compare DFT results for the deuterated and (13)C(18)O-labeled peptide with those from spectroscopic maps developed and used previously by the Skinner group. We find that the maps are typically accurate to within a few cm(-1) for both frequencies and couplings, having larger errors only for the frequencies of terminal amides.
Controlling Parametric Resonance
DEFF Research Database (Denmark)
Galeazzi, Roberto; Pettersen, Kristin Ytterstad
2012-01-01
if the system undergoing it could transform the large amplitude motion into, for example, energy. Therefore the development of control strategies to induce parametric resonance into a system can be as valuable as those which aim at stabilizing the resonant oscillations. By means of a mechanical equivalent......Parametric resonance is a resonant phenomenon which takes place in systems characterized by periodic variations of some parameters. While seen as a threatening condition, whose onset can drive a system into instability, this chapter advocates that parametric resonance may become an advantage...... the authors review the conditions for the onset of parametric resonance, and propose a nonlinear control strategy in order to both induce the resonant oscillations and to stabilize the unstable motion. Lagrange’s theory is used to derive the dynamics of the system and input–output feedback linearization...
Gardner, Andy
2009-01-01
The problem of adaptation is to explain the apparent design of organisms. Darwin solved this problem with the theory of natural selection. However, population geneticists, whose responsibility it is to formalize evolutionary theory, have long neglected the link between natural selection and organismal design. Here, I review the major historical developments in theory of organismal adaptation, clarifying what adaptation is and what it is not, and I point out future avenues for research.
Electron paramagnetic resonance
Al'tshuler, S A
2013-01-01
Electron Paramagnetic Resonance is a comprehensive text on the field of electron paramagnetic resonance, covering both the theoretical background and the results of experiment. This book is composed of eight chapters that cover theoretical materials and experimental data on ionic crystals, since these are the materials that have been most extensively studied by the methods of paramagnetic resonance. The opening chapters provide an introduction to the basic principles of electron paramagnetic resonance and the methods of its measurement. The next chapters are devoted to the theory of spectra an
Durai, Mithila; Searchfield, Grant D.
2017-01-01
Objectives: A randomized cross-over trial in 18 participants tested the hypothesis that nature sounds, with unpredictable temporal characteristics and high valence would yield greater improvement in tinnitus than constant, emotionally neutral broadband noise. Study Design: The primary outcome measure was the Tinnitus Functional Index (TFI). Secondary measures were: loudness and annoyance ratings, loudness level matches, minimum masking levels, positive and negative emotionality, attention reaction and discrimination time, anxiety, depression and stress. Each sound was administered using MP3 players with earbuds for 8 continuous weeks, with a 3 week wash-out period before crossing over to the other treatment sound. Measurements were undertaken for each arm at sound fitting, 4 and 8 weeks after administration. Qualitative interviews were conducted at each of these appointments. Results: From a baseline TFI score of 41.3, sound therapy resulted in TFI scores at 8 weeks of 35.6; broadband noise resulted in significantly greater reduction (8.2 points) after 8 weeks of sound therapy use than nature sounds (3.2 points). The positive effect of sound on tinnitus was supported by secondary outcome measures of tinnitus, emotion, attention, and psychological state, but not interviews. Tinnitus loudness level match was higher for BBN at 8 weeks; while there was little change in loudness level matches for nature sounds. There was no change in minimum masking levels following sound therapy administration. Self-reported preference for one sound over another did not correlate with changes in tinnitus. Conclusions: Modeled under an adaptation level theory framework of tinnitus perception, the results indicate that the introduction of broadband noise shifts internal adaptation level weighting away from the tinnitus signal, reducing tinnitus magnitude. Nature sounds may modify the affective components of tinnitus via a secondary, residual pathway, but this appears to be less important
Adaptive fuzzy system for 3-D vision
Mitra, Sunanda
1993-01-01
An adaptive fuzzy system using the concept of the Adaptive Resonance Theory (ART) type neural network architecture and incorporating fuzzy c-means (FCM) system equations for reclassification of cluster centers was developed. The Adaptive Fuzzy Leader Clustering (AFLC) architecture is a hybrid neural-fuzzy system which learns on-line in a stable and efficient manner. The system uses a control structure similar to that found in the Adaptive Resonance Theory (ART-1) network to identify the cluster centers initially. The initial classification of an input takes place in a two stage process; a simple competitive stage and a distance metric comparison stage. The cluster prototypes are then incrementally updated by relocating the centroid positions from Fuzzy c-Means (FCM) system equations for the centroids and the membership values. The operational characteristics of AFLC and the critical parameters involved in its operation are discussed. The performance of the AFLC algorithm is presented through application of the algorithm to the Anderson Iris data, and laser-luminescent fingerprint image data. The AFLC algorithm successfully classifies features extracted from real data, discrete or continuous, indicating the potential strength of this new clustering algorithm in analyzing complex data sets. The hybrid neuro-fuzzy AFLC algorithm will enhance analysis of a number of difficult recognition and control problems involved with Tethered Satellite Systems and on-orbit space shuttle attitude controller.
Powell, Joanne L; Grossi, Davide; Corcoran, Rhiannon; Gobet, Fernand; García-Fiñana, Marta
2017-07-04
Chess involves the capacity to reason iteratively about potential intentional choices of an opponent and therefore involves high levels of explicit theory of mind [ToM] (i.e. ability to infer mental states of others) alongside clear, strategic rule-based decision-making. Functional magnetic resonance imaging was used on 12 healthy male novice chess players to identify cortical regions associated with chess, ToM and empathizing. The blood-oxygenation-level-dependent (BOLD) response for chess and empathizing tasks was extracted from each ToM region. Results showed neural overlap between ToM, chess and empathizing tasks in right-hemisphere temporo-parietal junction (TPJ) [BA40], left-hemisphere superior temporal gyrus [BA22] and posterior cingulate gyrus [BA23/31]. TPJ is suggested to underlie the capacity to reason iteratively about another's internal state in a range of tasks. Areas activated by ToM and empathy included right-hemisphere orbitofrontal cortex and bilateral middle temporal gyrus: areas that become active when there is need to inhibit one's own experience when considering the internal state of another and for visual evaluation of action rationality. Results support previous findings, that ToM recruits a neural network with each region sub-serving a supporting role depending on the nature of the task itself. In contrast, a network of cortical regions primarily located within right- and left-hemisphere medial-frontal and parietal cortex, outside the internal representational network, was selectively recruited during the chess task. We hypothesize that in our cohort of novice chess players the strategy was to employ an iterative thinking pattern which in part involved mentalizing processes and recruited core ToM-related regions. Copyright © 2017. Published by Elsevier Ltd.
DEFF Research Database (Denmark)
Shang, Yunlong; Zhang, Chenghui; Cui, Naxin
2015-01-01
and electromagnetic interference (EMI). Furthermore, an adaptive fuzzy logic control (AFLC) algorithm is employed to online regulate the equalization period according to the voltage difference between cells and the cell voltage, not only greatly abbreviating the balancing time but also effectively preventing over......The equalization speed, efficiency, and control are the key issues of battery equalization. This paper proposes a crossed pack-to-cell equalizer based on quasi-resonant LC converter (QRLCC). The battery string is divided into M modules, and each module consists of N series-connected cells...
Perturbation theory of quantum resonances
Czech Academy of Sciences Publication Activity Database
Durand, P.; Paidarová, Ivana
2016-01-01
Roč. 135, č. 7 (2016), s. 159 ISSN 1432-2234 Institutional support: RVO:61388955 Keywords : Partitioning technique * Analytic continuation * Perturbative expansion Subject RIV: CF - Physical ; Theoretical Chemistry
Aubin, Jean-Pierre; Saint-Pierre, Patrick
2011-01-01
Viability theory designs and develops mathematical and algorithmic methods for investigating the adaptation to viability constraints of evolutions governed by complex systems under uncertainty that are found in many domains involving living beings, from biological evolution to economics, from environmental sciences to financial markets, from control theory and robotics to cognitive sciences. It involves interdisciplinary investigations spanning fields that have traditionally developed in isolation. The purpose of this book is to present an initiation to applications of viability theory, explai
Dicker, Gertjan J.; van Spronsen, Peter H.; van Ginkel, Floris C.; Castelijns, Jonas A.; van Schijndel, Ronald A.; Boom, Heleen P. W.; Tuinzing, D. Bram
Objective. Surgical mandibular advancement procedures induce major adaptations of jaw-closing muscles. In this study, adaptation of antagonist muscles, the lateral pterygoid (LPM) and anterior digastric (DigA) muscles, was evaluated. Study design. Eighteen adult patients with mandibular retrognathia
Datta, Dipayan; Gauss, Jürgen
2014-09-14
An analytic scheme is presented for the evaluation of first derivatives of the energy for a unitary group based spin-adapted coupled cluster (CC) theory, namely, the combinatoric open-shell CC (COSCC) approach within the singles and doubles approximation. The widely used Lagrange multiplier approach is employed for the derivation of an analytical expression for the first derivative of the energy, which in combination with the well-established density-matrix formulation, is used for the computation of first-order electrical properties. Derivations of the spin-adapted lambda equations for determining the Lagrange multipliers and the expressions for the spin-free effective density matrices for the COSCC approach are presented. Orbital-relaxation effects due to the electric-field perturbation are treated via the Z-vector technique. We present calculations of the dipole moments for a number of doublet radicals in their ground states using restricted open-shell Hartree-Fock (ROHF) and quasi-restricted HF (QRHF) orbitals in order to demonstrate the applicability of our analytic scheme for computing energy derivatives. We also report calculations of the chlorine electric-field gradients and nuclear quadrupole-coupling constants for the CCl, CH2Cl, ClO2, and SiCl radicals.
Yourdkhani, Sirous; Korona, Tatiana; Hadipour, Nasser L
2015-12-15
Intermolecular ternary complexes composed of: (1) the centrally placed trifluoroacetonitrile or its higher analogs with central carbon exchanged by silicon or germanium (M = C, Si, Ge), (2) the benzonitrile molecule or its para derivatives on one side, and (3) the boron trifluoride of trichloride molecule (X = F, Cl) on the opposite side as well as the corresponding intermolecular tetrel- and triel-bonded binary complexes, were investigated by symmetry-adapted perturbation theory (SAPT) and the supermolecular Møller-Plesset method (MP2) at the complete basis set limit for optimized geometries. A character of interactions was studied by quantum theory of atoms-in-molecules (QTAIM). A comparison of interaction energies and QTAIM bond descriptors for dimers and trimers reveals that tetrel and triel bonds increase in their strength if present together in the trimer. For the triel-bonded complex, this growth leads to a change of the bond character from closed-shell to partly covalent for Si or Ge tetrel atoms, so the resulting bonding scheme corresponds to a preliminary stage of the SN2 reaction. Limitations of the Lewis theory of acids and bases were shown by its failure in predicting the stability order of the triel complexes. The necessity of including interaction energy terms beyond the electrostatic component for an elucidation of the nature of σ- and π-holes was presented by a SAPT energy decomposition and by a study of differences in monomer electrostatic potentials obtained either from isolated monomer densities, or from densities resulting from a perturbation with the effective field of another monomer. © 2015 Wiley Periodicals, Inc.
Lattices of dielectric resonators
Trubin, Alexander
2016-01-01
This book provides the analytical theory of complex systems composed of a large number of high-Q dielectric resonators. Spherical and cylindrical dielectric resonators with inferior and also whispering gallery oscillations allocated in various lattices are considered. A new approach to S-matrix parameter calculations based on perturbation theory of Maxwell equations, developed for a number of high-Q dielectric bodies, is introduced. All physical relationships are obtained in analytical form and are suitable for further computations. Essential attention is given to a new unified formalism of the description of scattering processes. The general scattering task for coupled eigen oscillations of the whole system of dielectric resonators is described. The equations for the expansion coefficients are explained in an applicable way. The temporal Green functions for the dielectric resonator are presented. The scattering process of short pulses in dielectric filter structures, dielectric antennas and lattices of d...
Advances in magnetic and optical resonance
Warren, Warren S
1997-01-01
Since 1965, Advances in Magnetic and Optical Resonance has provided researchers with timely expositions of fundamental new developments in the theory of, experimentation with, and application of magnetic and optical resonance.
Bugental, Daphne Blunt
2012-01-01
Children's physiological reactions to stress are presented from the broader theoretical perspective of adaptive calibration to the environment, as rooted in life history theory. Del Giudice, Hinnant, Ellis, and El-Sheikh (2012) focus on children's physiological responses to a stressful task as a consequence of their history of family stress.…
Gardner, Andy
2017-01-01
A central feature of Darwin’s theory of natural selection is that it explains the purpose of biological adaptation. Here, I: emphasise the scientific importance of understanding what adaptations are for, in terms of facilitating the derivation of empirically-testable predictions; discuss the population genetical basis for Darwin’s theory of the purpose of adaptation, with reference to the “fundamental theorem of natural selection”; and show that a deeper understanding of the purpose of adapta...
Hapka, Michał; Żuchowski, Piotr S; Szczęśniak, Małgorzata M; Chałasiński, Grzegorz
2012-10-28
Two open-shell formulations of the symmetry-adapted perturbation theory are presented. They are based on the spin-unrestricted Kohn-Sham (SAPT(UKS)) and unrestricted Hartree-Fock (SAPT(UHF)) descriptions of the monomers, respectively. The key reason behind development of SAPT(UKS) is that it is more compatible with density functional theory (DFT) compared to the previous formulation of open-shell SAPT based on spin-restricted Kohn-Sham method of Żuchowski et al. [J. Chem. Phys. 129, 084101 (2008)]. The performance of SAPT(UKS) and SAPT(UHF) is tested for the following open-shell van der Waals complexes: He···NH, H(2)O···HO(2), He···OH, Ar···OH, Ar···NO. The results show an excellent agreement between SAPT(UKS) and SAPT(ROKS). Furthermore, for the first time SAPT based on DFT is shown to be suitable for the treatment of interactions involving Π-state radicals (He···OH, Ar···OH, Ar···NO). In the interactions of transition metal dimers ((3)Σ(u)(+))Au(2) and ((13)Σ(g)(+))Cr(2) we show that SAPT is incompatible with the use of effective core potentials. The interaction energies of both systems expressed instead as supermolecular UHF interaction plus dispersion from SAPT(UKS) result in reasonably accurate potential curves.
Doubly resonant multiphoton ionization
International Nuclear Information System (INIS)
Crance, M.
1978-01-01
A particular case of doubly resonant multiphoton ionization is theoretically investigated. More precisely, two levels quasi-resonant with two successive harmonics of the field frequency are considered. The method used is based on the effective operator formalism first introduced for this problem by Armstrong, Beers and Feneuille. The main result is to show the possibility of observing large interference effects on the width of the resonances. Moreover this treatment allows us to make more precise the connection between effective operator formalism and standard perturbation theory
Is adaptation. Truly an adaptation? Is adaptation. Truly an adaptation?
Directory of Open Access Journals (Sweden)
Thais Flores Nogueira Diniz
2008-04-01
Full Text Available The article begins by historicizing film adaptation from the arrival of cinema, pointing out the many theoretical approaches under which the process has been seen: from the concept of “the same story told in a different medium” to a comprehensible definition such as “the process through which works can be transformed, forming an intersection of textual surfaces, quotations, conflations and inversions of other texts”. To illustrate this new concept, the article discusses Spike Jonze’s film Adaptation. according to James Naremore’s proposal which considers the study of adaptation as part of a general theory of repetition, joined with the study of recycling, remaking, and every form of retelling. The film deals with the attempt by the scriptwriter Charles Kaufman, cast by Nicholas Cage, to adapt/translate a non-fictional book to the cinema, but ends up with a kind of film which is by no means what it intended to be: a film of action in the model of Hollywood productions. During the process of creation, Charles and his twin brother, Donald, undergo a series of adventures involving some real persons from the world of film, the author and the protagonist of the book, all of them turning into fictional characters in the film. In the film, adaptation then signifies something different from itstraditional meaning. The article begins by historicizing film adaptation from the arrival of cinema, pointing out the many theoretical approaches under which the process has been seen: from the concept of “the same story told in a different medium” to a comprehensible definition such as “the process through which works can be transformed, forming an intersection of textual surfaces, quotations, conflations and inversions of other texts”. To illustrate this new concept, the article discusses Spike Jonze’s film Adaptation. according to James Naremore’s proposal which considers the study of adaptation as part of a general theory of repetition
Directory of Open Access Journals (Sweden)
Zewdie Birhanu
2017-01-01
Full Text Available Recurrent shocks and stresses are increasingly deteriorating pastoralist communities’ resilience capacities in many aspects. A context specific resilience framework is essential to strengthen pastoralist community’s resilience capacity towards the impact of recurrent drought. Hence, the present study was aimed to develop a context specific and data driven resilience building framework towards impacts of recurrent droughts in the case of Borana pastoralists in Ethiopia. Qualitative grounded theory approach was employed to guide the study process. The data were collected through focus group discussions and in-depth interviews in two drought affected districts of Borana Zone during October 2013. The analysis was assisted by ATLAS. ti 7.1.4. The analysis provided a context specific resilience building conceptual tool, which consists of, closely interconnected, eight dimensions operating at multiple capacities and levels: environment (underlying vulnerability factor; livestock, infrastructures/social services, and wealth (immediate causes and effects; community network/social capital, as well as governance, peace and security (support and enabling factors oriented, psychosocial, and human capital (as eventual outcomes and impacts. The resilience capacities of these pastoralist communities have been eroded, leaving them without sufficient and effective adaptive strategies. The emergent resilience framework can serve as a useful guidance to design context-specific interventions that makes the people and the system resilient to the impacts of recurrent droughts.
International Nuclear Information System (INIS)
Hategan, Cornel
2002-01-01
Theory of Threshold Phenomena in Quantum Scattering is developed in terms of Reduced Scattering Matrix. Relationships of different types of threshold anomalies both to nuclear reaction mechanisms and to nuclear reaction models are established. Magnitude of threshold effect is related to spectroscopic factor of zero-energy neutron state. The Theory of Threshold Phenomena, based on Reduced Scattering Matrix, does establish relationships between different types of threshold effects and nuclear reaction mechanisms: the cusp and non-resonant potential scattering, s-wave threshold anomaly and compound nucleus resonant scattering, p-wave anomaly and quasi-resonant scattering. A threshold anomaly related to resonant or quasi resonant scattering is enhanced provided the neutron threshold state has large spectroscopic amplitude. The Theory contains, as limit cases, Cusp Theories and also results of different nuclear reactions models as Charge Exchange, Weak Coupling, Bohr and Hauser-Feshbach models. (author)
SAIDANI Lassaad
2017-01-01
The nokton theory is an attempt to construct a theory adapted to every physical phenomenon. Space and time have been discretized. Its laws are iterative and precise. Probability plays an important role here. At first I defined the notion of image function and its mathematical framework. The notion of nokton and its state are the basis of several definitions. I later defined the canonical image function and the canonical contribution. Two constants have been necessary to define the dynam...
SAIDANI Lassaad
2015-01-01
The nokton theory is an attempt to construct a theory adapted to every physical phenomenon. Space and time have been discretized. Its laws are iterative and precise. Probability plays an important role here. At first I defined the notion of image function and its mathematical framework. The notion of nokton and its state are the basis of several definitions. I later defined the canonical image function and the canonical contribution. Two constants have been necessary to define the dynam...
Padowitz, David; Matsiev, L; Kolosov, Oleg
2004-01-01
A sensor and methods for making and using the same in which a mechanical resonator is employed, comprising a resonator portion for resonating in a fluid without the substantial generation of acoustic waves; and an electrical connection between the resonator portion for oscillating and a source of an input signal; wherein the portion for resonating, the electrical connection or both includes a base material and a performance-tuning material that is different from the base material.
Adaptation and Foreign Policy Theory
1973-09-01
Chomsky , 1956:113, points out, "A properly formulated grammar should define unambiguously the set of grammatical sentences." The theorist of...which Institutionally designated decision- makers seek to manipulate the International environment." This consis- tency, of course, requires the
Advances in magnetic resonance 11
Waugh, John S
2013-01-01
Advances in Magnetic Resonance, Volume 11, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains three chapters and begins with a discussion of the principles and applications of dynamic nuclear polarization, with emphasis on molecular motions and collisions, intermolecular couplings, and chemical interactions. Subsequent chapters focus on the assessment of a proposed broadband decoupling method and studies of time-domain (or Fourier transform) multiple-quantum nuclear magnetic resonance.
Spectra of resonance surface photoionization
Energy Technology Data Exchange (ETDEWEB)
Antsiferov, V.V.; Smirnov, G.I.; Telegin, G.G. [Budker Nuclear Physics Institute, Novosibirsk (Russian Federation)
1995-09-01
The theory of nonactivated electron transfer between atoms interacting reasonantly with coherent radiation and a metal surface is developed. The spectral resonances in photoabsorption and surface photoionization are found to be related to nonlinear interference effects in the interaction between discrete atomic levels and the continuum formed by the quasi-continuous electron spectrum of a normal metal. The asymmetry in the resonance surface photoionization spectrum is shown to have a shape typical of the Fano autoionization resonances. 18 refs.
Reinhardt, Carsten
2006-06-01
During the 1960s organic chemistry underwent a spectacular transformation as a result of the introduction of high-tech instruments. In this process, nuclear magnetic resonance (NMR) became an important analytical technique in organic chemistry. The theme of this essay is the relationship of Varian Associates of Palo Alto, California, the major manufacturer of NMR spectrometers up to the 1970s, with one early and crucial user, the organic chemist John D. Roberts, who was based at the California Institute of Technology in Pasadena. Roberts's research and teaching contributed to the fast and smooth acceptance of NMR in organic chemistry. He embraced the role of mediator between the instrument manufacturer, which had expertise mainly in physics and electrical engineering, and the customers, who were mostly organic chemists. This essay focuses on the tactics used by Roberts and James N. Shoolery at Varian Associates to implement novel types of instrumentation and on the modes of cooperation between instrument manufacturer and academic scientist.
Wang, Haipeng; Qiu, Liyun; Wang, Guangbin; Gao, Fei; Jia, Haipeng; Zhao, Junyu; Chen, Weibo; Wang, Cuiyan; Zhao, Bin
2017-06-01
The cardiac magnetic resonance (CMR) of children at 3.0 T presents a unique set of technical challenges because of their small cardiac anatomical structures, fast heart rates, and the limited ability to keep motionless and hold breathe, which could cause problems associated with field inhomogeneity and degrade the image quality. The aim of our study was to evaluate the effect of dual-source parallel radiofrequency (RF) transmission on the B1 homogeneity and image quality in children with CMR at 3.0 T. The study was approved by the institutional ethics committee and written informed consent was obtained. A total of 30 free-breathing children and 30 breath-hold children performed CMR examinations with dual-source and single-source RF transmission. The B1 homogeneity, contrast ratio (CR) of cine images, and off-resonance artifacts in cine images between dual-source and single-source RF transmission were assessed in free-breathing and breath-hold groups, respectively. In both free-breathing and breath-hold groups, higher mean percentage of flip angle (free-breathing group: 104.2 ± 4.6 vs 95.5 ± 6.3, P source than with single-source RF transmission. Both the CRs in the horizontal long axis (HLA) and short axis of cine images with dual-source RF transmission was improved (P source RF transmission were higher in both free-breathing and breath-hold groups (P source, dual-source parallel RF transmission could significantly improve the B1 homogeneity and image quality for CMR in children at 3.0 T. This technology could be taken into account in CMR for children with cardiac diseases.
Lee, William H K.
2016-01-01
A complex system consists of many interacting parts, generates new collective behavior through self organization, and adaptively evolves through time. Many theories have been developed to study complex systems, including chaos, fractals, cellular automata, self organization, stochastic processes, turbulence, and genetic algorithms.
International Nuclear Information System (INIS)
Konrad, F.; Nennig, E.; Kress, B.; Sartor, K.; Stippich, C.; Ochmann, H.
2005-01-01
Purpose: Functional magnetic resonance imaging (fMRI) localizes Broca's area (B) and Wernicke's area (W) and the hemisphere dominant for language. In clinical fMRI, adapting the stimulation paradigms to each patient's individual cognitive capacity is crucial for diagnostic success. To interpret clinical fMRI findings correctly, we studied the effect of varying frequency and number of stimuli on functional localization, determination of language dominance and BOLD signals. Materials and Methods: Ten volunteers (VP) were investigated at 1.5 Tesla during visually triggered sentence generation using a standardized block design. In four different measurements, the stimuli were presented to each VP with frequencies of (1/1)s, (1/2)s,(1/3)s and (1/6)s. Results: The functional localizations and the correlations of the measured BOLD signals to the applied hemodynamic reference function (r) were almost independent from frequency and number of the stimuli in both hemispheres, whereas the relative BOLD signal changes (ΔS) in B and W increased with the stimulation rate, which also changed the lateralization indices. The strongest BOLD activations were achieved with the highest stimulation rate or with the maximum language production task, respectively. Conclusion: The adaptation of language paradigms necessary in clinical fMRI does not alter the functional localizations but changes the BOLD signals and language lateralization which should not be attributed to the underlying brain pathology. (orig.)
Konrad, F; Nennig, E; Ochmann, H; Kress, B; Sartor, K; Stippich, C
2005-03-01
Functional magnetic resonance imaging (fMRI) localizes Broca's area (B) and Wernicke's area (W) and the hemisphere dominant for language. In clinical fMRI, adapting the stimulation paradigms to each patient's individual cognitive capacity is crucial for diagnostic success. To interpret clinical fMRI findings correctly, we studied the effect of varying frequency and number of stimuli on functional localization, determination of language dominance and BOLD signals. Ten volunteers (VP) were investigated at 1.5 Tesla during visually triggered sentence generation using a standardized block design. In four different measurements, the stimuli were presented to each VP with frequencies of 1/1 s, (1/2) s, (1/3) s and (1/6) s. The functional localizations and the correlations of the measured BOLD signals to the applied hemodynamic reference function (r) were almost independent from frequency and number of the stimuli in both hemispheres, whereas the relative BOLD signal changes (DeltaS) in B and W increased with the stimulation rate, which also changed the lateralization indices. The strongest BOLD activations were achieved with the highest stimulation rate or with the maximum language production task, respectively. The adaptation of language paradigms necessary in clinical fMRI does not alter the functional localizations but changes the BOLD signals and language lateralization which should not be attributed to the underlying brain pathology.
Parametric Resonance in Dynamical Systems
Nijmeijer, Henk
2012-01-01
Parametric Resonance in Dynamical Systems discusses the phenomenon of parametric resonance and its occurrence in mechanical systems,vehicles, motorcycles, aircraft and marine craft, and micro-electro-mechanical systems. The contributors provide an introduction to the root causes of this phenomenon and its mathematical equivalent, the Mathieu-Hill equation. Also included is a discussion of how parametric resonance occurs on ships and offshore systems and its frequency in mechanical and electrical systems. This book also: Presents the theory and principles behind parametric resonance Provides a unique collection of the different fields where parametric resonance appears including ships and offshore structures, automotive vehicles and mechanical systems Discusses ways to combat, cope with and prevent parametric resonance including passive design measures and active control methods Parametric Resonance in Dynamical Systems is ideal for researchers and mechanical engineers working in application fields such as MEM...
Is adaptation. Truly an adaptation?
Directory of Open Access Journals (Sweden)
Thais Flores Nogueira Diniz
2006-04-01
Full Text Available The article begins by historicizing film adaptation from the arrival of cinema, pointing out the many theoretical approaches under which the process has been seen: from the concept of “the same story told in a different medium” to a comprehensible definition such as “the process through which works can be transformed, forming an intersection of textual surfaces, quotations, conflations and inversions of other texts”. To illustrate this new concept, the article discusses Spike Jonze’s film Adaptation. according to James Naremore’s proposal which considers the study of adaptation as part of a general theory of repetition, joined with the study of recycling, remaking, and every form of retelling. The film deals with the attempt by the scriptwriter Charles Kaufman, cast by Nicholas Cage, to adapt/translate a non-fictional book to the cinema, but ends up with a kind of film which is by no means what it intended to be: a film of action in the model of Hollywood productions. During the process of creation, Charles and his twin brother, Donald, undergo a series of adventures involving some real persons from the world of film, the author and the protagonist of the book, all of them turning into fictional characters in the film. In the film, adaptation then signifies something different from itstraditional meaning.
Properties of spiral resonators
International Nuclear Information System (INIS)
Haeuser, J.
1989-10-01
The present thesis deals with the calculation and the study of the application possibilities of single and double spiral resonators. The main aim was the development and the construction of reliable and effective high-power spiral resonators for the UNILAC of the GSI in Darmstadt and the H - -injector for the storage ring HERA of DESY in Hamburg. After the presentation of the construction and the properties of spiral resonators and their description by oscillating-circuit models the theoretical foundations of the bunching are presented and some examples of a rebuncher and debuncher and their influence on the longitudinal particle dynamics are shown. After the description of the characteristic accelerator quantities by means of an oscillating-circuit model and the theory of an inhomogeneous λ/4 line it is shown, how the resonance frequency and the efficiency of single and double spiral resonators can be calculated from the geometrical quantities of the structure. In the following the dependence of the maximal reachable resonator voltage in dependence on the gap width and the surface of the drift tubes is studied. Furthermore the high-power resonators are presented, which were built for the different applications for the GSI in Darmstadt, DESY in Hamburg, and for the FOM Institute in Amsterdam. (orig./HSI) [de
International Nuclear Information System (INIS)
Tepikian, S.
1989-01-01
Siberian Snakes provide a practical means of obtaining polarized proton beams in large accelerators. The effect of snakes can be understood by studying the dynamics of spin precession in an accelerator with snakes and a single spin resonance. This leads to a new class of energy independent spin depolarizing resonances, called snake resonances. In designing a large accelerator with snakes to preserve the spin polarization, there is an added constraint on the choice of the vertical betatron tune due to the snake resonances
Dorda, Antonius; Schürrer, Ferdinand
2015-03-01
We present a novel numerical scheme for the deterministic solution of the Wigner transport equation, especially suited to deal with situations in which strong quantum effects are present. The unique feature of the algorithm is the expansion of the Wigner function in local basis functions, similar to finite element or finite volume methods. This procedure yields a discretization of the pseudo-differential operator that conserves the particle density on arbitrarily chosen grids. The high flexibility in refining the grid spacing together with the weighted essentially non-oscillatory (WENO) scheme for the advection term allows for an accurate and well-resolved simulation of the phase space dynamics. A resonant tunneling diode is considered as test case and a detailed convergence study is given by comparing the results to a non-equilibrium Green's functions calculation. The impact of the considered domain size and of the grid spacing is analyzed. The obtained convergence of the results towards a quasi-exact agreement of the steady state Wigner and Green's functions computations demonstrates the accuracy of the scheme, as well as the high flexibility to adjust to different physical situations.
Facilitating climate change adaptation through communication
DEFF Research Database (Denmark)
Glaas, Erik; Gammelgaard Ballantyne, Anne; Neset, Tina Simone
2015-01-01
Climate change communication on anticipated impacts and adaptive responses is frequently presented as an effective means to facilitate implementation of adaptation to mitigate risks to residential buildings. However, it requires that communication is developed in a way that resonates...
849 RESONANCE | September 2013
Indian Academy of Sciences (India)
IAS Admin
849. RESONANCE | September 2013. Page 2. 850. RESONANCE | September 2013. Page 3. 851. RESONANCE | September 2013. Page 4. 852. RESONANCE | September 2013. Page 5. 853. RESONANCE | September 2013. Page 6. 854. RESONANCE | September 2013. Page 7. 855. RESONANCE | September 2013.
Advances in magnetic resonance 12
Waugh, John S
2013-01-01
Advances in Magnetic Resonance, Volume 12, presents a variety of contributions to the theory and practice of magnetic resonance. The book contains six chapters and begins with a discussion of diffusion and self-diffusion measurements by nuclear magnetic resonance. This is followed by separate chapters on spin-lattice relaxation time in hydrogen isotope mixtures; the principles of optical detection of nuclear spin alignment and nuclear quadropole resonance; and the spin-1 behavior, including the relaxation of the quasi-invariants of the motion of a system of pairs of dipolar coupled spin-1/2 nu
Millerd, James E.; Garmire, Elsa M.; Klein, Marvin B.
1992-01-01
Data showing nonlinear resonantly enhanced photorefractive response at high modulation depths in InP:Fe are presented. A simple empirical model is used to describe the behavior. Next the impact of these large-signal effects, as well as linear absorption, on the self-pumped phase-conjugate mirror is examined. Predicted performance is compared to actual measurements of a ring self-pumped phase-conjugate mirror using InP. The performance of the double-pumped phase-conjugate mirror is also examined experimentally and compared with the performance of the ring mirror.
Directory of Open Access Journals (Sweden)
Jeremy R. Dunklin
2017-01-01
Full Text Available Polymer films containing plasmonic nanostructures are of increasing interest for development of responsive energy, sensing, and therapeutic systems. The present work evaluates heat dissipated from power absorbed by resonant gold (Au nanoparticles (NP with negligible Rayleigh scattering cross sections randomly dispersed in polydimethylsiloxane (PDMS films. Finite element analysis (FEA of heat transport was coordinated with characterization of resonant absorption by Mie theory and coupled dipole approximation (CDA. At AuNP particle separation greater than resonant wavelength, correspondence was observed between measured and CDA-predicted optical absorption and FEA-derived power dissipation. At AuNP particle separation less than resonant wavelength, measured extinction increased relative to predicted values, while FEA-derived power dissipation remained comparable to CDA-predicted power absorption before lagging observed extinguished power at higher AuNP content and resulting particle separation. Effects of isolated particles, for example, scattering, and particle-particle interactions, for example, multiple scattering, aggregation on observed optothermal activity were evaluated. These complementary approaches to distinguish contributions to resonant heat dissipation from isolated particle absorption and interparticle interactions support design and adaptive control of thermoplasmonic materials for a variety of implementations.
Quartz resonator processing system
Peters, Roswell D. M.
1983-01-01
Disclosed is a single chamber ultra-high vacuum processing system for the oduction of hermetically sealed quartz resonators wherein electrode metallization and sealing are carried out along with cleaning and bake-out without any air exposure between the processing steps. The system includes a common vacuum chamber in which is located a rotatable wheel-like member which is adapted to move a plurality of individual component sets of a flat pack resonator unit past discretely located processing stations in said chamber whereupon electrode deposition takes place followed by the placement of ceramic covers over a frame containing a resonator element and then to a sealing stage where a pair of hydraulic rams including heating elements effect a metallized bonding of the covers to the frame.
International Nuclear Information System (INIS)
1977-03-01
At the 1975 Particle Accelerator Conference it was reported that a class of resonances were observed in SPEAR II that had not appeared before in SPEAR I. While the existence of sideband resonances of the main betatron oscillation frequencies has been previously observed and analyzed, the resonances observed in SPEAR do not appear to be of the same variety. Experiments were performed at SPEAR to identify the mechanism believed to be the most likely explanation. Some of the current experimental knowledge and theoretical views on the source of these resonances are presented
International Nuclear Information System (INIS)
Tepikian, S.
1988-01-01
Siberian Snakes provide a practical means of obtaining polarized proton beams in large accelerators. The effect of snakes can be understood by studying the dynamics of spin precession in an accelerator with snakes and a single spin resonance. This leads to a new class of energy independent spin depolarizing resonances, called snake resonances. In designing a large accelerator with snakes to preserve the spin polarization, there is an added constraint on the choice of the vertical betatron tune due to the snake resonances. 11 refs., 4 figs
McNamee, Paul; Madden, Dave; McNamee, Frank; Wall, John; Hurst, Alan; Vrasidas, Charalambos; Chanquoy, Lucile; Baccino, Thierry; Acar, Emrah; Onwy-Yazici, Ela; Jordan, Ann
2009-01-01
This paper describes an ongoing EU project concerned with developing an instructional design framework for virtual classes (VC) that is based on the theory of Multiple Intelligences (MI) (1983). The psychological theory of Multiple Intelligences (Gardner 1983) has received much credence within instructional design since its inception and has been…
International Nuclear Information System (INIS)
Nakatsuji, H.
1979-01-01
The solutions of the SAC (symmetry-adapated-cluster) and SAC CI theories for the study of electron correlations in ground and excited states, respectively have been summarized. Variational and non-variational solutions are considered for both theories and their features are discussed. (Auth.)
International Nuclear Information System (INIS)
Wong, C.F.; Light, J.C.
1984-01-01
Based on the R-matrix approach of Schneider et al. [J. Phys. B 12, L 365 (1979)] to reactive electron-molecule scattering, a new propagative R-matrix method (PRMM) is presented which is more appropriate for polyatomic systems. The new method should be useful in other calculations where complicated integrals need to be propagated. We also introduce an effective R-matrix model (ERMM) in which the usual resonance parameters (potential and width) can be used as input in model R-matrix calculations. The PRMM and ERMM have been applied to the electron-N 2 system and the electron-F 2 system. The results agree very well with previous calculations for both vibrationally inelastic scattering and dissociative attachment when identical potentials and parameters are used
Directory of Open Access Journals (Sweden)
Wendy Wendy
2014-08-01
Full Text Available This study analyzes the stock investor's rational and irrational behavior formation through Investor's Adaptation model. Hypotheses testings were conducted by manipulating four market conditions using between-subject experimental design. The results supported the hypotheses proposed in this study. When given treatment one (opportunity-high control, investors tended to adapt the proﬁt maximizing strategy (rational. Meanwhile, when given treatment two (opportunity-low control, three (threat-high control and four (threat-low control, they tended to adapt the proﬁt satisfying strategy (rational-emotional, bad news handling strategy (emotional-rational, and self-preserving strategy (irrational respectively. The application of rational strategies are intended to obtain personal beneﬁts and proﬁt, while adapting irrational strategy is intended to recover emotional stability and reduce some other tensions. Another ﬁnding showed that for the investors, the relatively irrational decision formation was "harder" than that of rational.
Electrothermally Tunable Bridge Resonator
Hajjaj, Amal Z.
2016-12-05
This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of an in-plane clamped-clamped microbeam, bridge, and resonator compressed by a force due to electrothermal actuation. We demonstrate that a single resonator can be operated at a wide range of frequencies. The microbeam is actuated electrothermally, by passing a DC current through it. We show that when increasing the electrothermal voltage, the compressive stress inside the microbeam increases, which leads eventually to its buckling. Before buckling, the fundamental frequency decreases until it drops to very low values, almost to zero. After buckling, the fundamental frequency increases, which is shown to be as high as twice the original resonance frequency. Analytical results based on the Galerkin discretization of the Euler Bernoulli beam theory are generated and compared to the experimental data and to simulation results of a multi-physics finite-element model. A good agreement is found among all the results.
Adaptation Research in Rehabilitation Counseling
Parker, Randall M.
2007-01-01
This paper reviews current research concerning psychosocial adaptation to chronic illness and disability and presents recommendations for future development of theories in this area. First, those who craft or adapt theories must use nondisabling, respectful, and empowering language. Rehabilitation professionals must avoid terms that connote…
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 11. Combinatorial Group Theory Group Theory via Generators and Relations. B Sury. General Article Volume 1 Issue 11 November 1996 pp 42-50. Fulltext. Click here to view fulltext PDF. Permanent link:
Ghobadi, Ahmadreza F.; Elliott, J. Richard
2014-07-01
In this work, a new classical density functional theory is developed for group-contribution equations of state (EOS). Details of implementation are demonstrated for the recently-developed SAFT-γ WCA EOS and selective applications are studied for confined fluids and vapor-liquid interfaces. The acronym WCA (Weeks-Chandler-Andersen) refers to the characterization of the reference part of the third-order thermodynamic perturbation theory applied in formulating the EOS. SAFT-γ refers to the particular form of "statistical associating fluid theory" that is applied to the fused-sphere, heteronuclear, united-atom molecular models of interest. For the monomer term, the modified fundamental measure theory is extended to WCA-spheres. A new chain functional is also introduced for fused and soft heteronuclear chains. The attractive interactions are taken into account by considering the structure of the fluid, thus elevating the theory beyond the mean field approximation. The fluctuations of energy are also included via a non-local third-order perturbation theory. The theory includes resolution of the density profiles of individual groups such as CH2 and CH3 and satisfies stoichiometric constraints for the density profiles. New molecular simulations are conducted to demonstrate the accuracy of each Helmholtz free energy contribution in reproducing the microstructure of inhomogeneous systems at the united-atom level of coarse graining. At each stage, comparisons are made to assess where the present theory stands relative to the current state of the art for studying inhomogeneous fluids. Overall, it is shown that the characteristic features of real molecular fluids are captured both qualitatively and quantitatively. For example, the average pore density deviates ˜2% from simulation data for attractive pentadecane in a 2-nm slit pore. Another example is the surface tension of ethane/heptane mixture, which deviates ˜1% from simulation data while the theory reproduces the excess
DEFF Research Database (Denmark)
2014-01-01
The present invention relates to a method for detecting photo-thermal absorbance of a material utilising a mechanically temperature sensitive resonator (20) and a sample being arrange in thermal communication with the temperature sensitive resonator. The present invention further relates...
Rajasekar, Shanmuganathan
2016-01-01
This introductory text presents the basic aspects and most important features of various types of resonances and anti-resonances in dynamical systems. In particular, for each resonance, it covers the theoretical concepts, illustrates them with case studies, and reviews the available information on mechanisms, characterization, numerical simulations, experimental realizations, possible quantum analogues, applications and significant advances made over the years. Resonances are one of the most fundamental phenomena exhibited by nonlinear systems and refer to specific realizations of maximum response of a system due to the ability of that system to store and transfer energy received from an external forcing source. Resonances are of particular importance in physical, engineering and biological systems - they can prove to be advantageous in many applications, while leading to instability and even disasters in others. The book is self-contained, providing the details of mathematical derivations and techniques invo...
International Nuclear Information System (INIS)
Ghobadi, Ahmadreza F.; Elliott, J. Richard
2014-01-01
In this work, a new classical density functional theory is developed for group-contribution equations of state (EOS). Details of implementation are demonstrated for the recently-developed SAFT-γ WCA EOS and selective applications are studied for confined fluids and vapor-liquid interfaces. The acronym WCA (Weeks-Chandler-Andersen) refers to the characterization of the reference part of the third-order thermodynamic perturbation theory applied in formulating the EOS. SAFT-γ refers to the particular form of “statistical associating fluid theory” that is applied to the fused-sphere, heteronuclear, united-atom molecular models of interest. For the monomer term, the modified fundamental measure theory is extended to WCA-spheres. A new chain functional is also introduced for fused and soft heteronuclear chains. The attractive interactions are taken into account by considering the structure of the fluid, thus elevating the theory beyond the mean field approximation. The fluctuations of energy are also included via a non-local third-order perturbation theory. The theory includes resolution of the density profiles of individual groups such as CH 2 and CH 3 and satisfies stoichiometric constraints for the density profiles. New molecular simulations are conducted to demonstrate the accuracy of each Helmholtz free energy contribution in reproducing the microstructure of inhomogeneous systems at the united-atom level of coarse graining. At each stage, comparisons are made to assess where the present theory stands relative to the current state of the art for studying inhomogeneous fluids. Overall, it is shown that the characteristic features of real molecular fluids are captured both qualitatively and quantitatively. For example, the average pore density deviates ∼2% from simulation data for attractive pentadecane in a 2-nm slit pore. Another example is the surface tension of ethane/heptane mixture, which deviates ∼1% from simulation data while the theory reproduces
Electrothermally Tunable Arch Resonator
Hajjaj, Amal Z.
2017-03-18
This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of electrothermally actuated microelectromechanical arch beams. The beams are made of silicon and are intentionally fabricated with some curvature as in-plane shallow arches. An electrothermal voltage is applied between the anchors of the beam generating a current that controls the axial stress caused by thermal expansion. When the electrothermal voltage increases, the compressive stress increases inside the arch beam. This leads to an increase in its curvature, thereby increasing its resonance frequencies. We show here that the first resonance frequency can increase monotonically up to twice its initial value. We show also that after some electrothermal voltage load, the third resonance frequency starts to become more sensitive to the axial thermal stress, while the first resonance frequency becomes less sensitive. These results can be used as guidelines to utilize arches as wide-range tunable resonators. Analytical results based on the nonlinear Euler Bernoulli beam theory are generated and compared with the experimental data and the results of a multi-physics finite-element model. A good agreement is found among all the results. [2016-0291
Sen, Sangita; Shee, Avijit; Mukherjee, Debashis
2018-02-01
The orbital relaxation attendant on ionization is particularly important for the core electron ionization potential (core IP) of molecules. The Unitary Group Adapted State Universal Coupled Cluster (UGA-SUMRCC) theory, recently formulated and implemented by Sen et al. [J. Chem. Phys. 137, 074104 (2012)], is very effective in capturing orbital relaxation accompanying ionization or excitation of both the core and the valence electrons [S. Sen et al., Mol. Phys. 111, 2625 (2013); A. Shee et al., J. Chem. Theory Comput. 9, 2573 (2013)] while preserving the spin-symmetry of the target states and using the neutral closed-shell spatial orbitals of the ground state. Our Ansatz invokes a normal-ordered exponential representation of spin-free cluster-operators. The orbital relaxation induced by a specific set of cluster operators in our Ansatz is good enough to eliminate the need for different sets of orbitals for the ground and the core-ionized states. We call the single configuration state function (CSF) limit of this theory the Unitary Group Adapted Open-Shell Coupled Cluster (UGA-OSCC) theory. The aim of this paper is to comprehensively explore the efficacy of our Ansatz to describe orbital relaxation, using both theoretical analysis and numerical performance. Whenever warranted, we also make appropriate comparisons with other coupled-cluster theories. A physically motivated truncation of the chains of spin-free T-operators is also made possible by the normal-ordering, and the operational resemblance to single reference coupled-cluster theory allows easy implementation. Our test case is the prediction of the 1s core IP of molecules containing a single light- to medium-heavy nucleus and thus, in addition to demonstrating the orbital relaxation, we have addressed the scalar relativistic effects on the accuracy of the IPs by using a hierarchy of spin-free Hamiltonians in conjunction with our theory. Additionally, the contribution of the spin-free component of the two
DEFF Research Database (Denmark)
Carroll, Joseph; Clasen, Mathias; Jonsson, Emelie
2017-01-01
Biocultural theory is an integrative research program designed to investigate the causal interactions between biological adaptations and cultural constructions. From the biocultural perspective, cultural processes are rooted in the biological necessities of the human life cycle: specifically human...... and ideological beliefs, and artistic practices such as music, dance, painting, and storytelling. Establishing biocultural theory as a program that self-consciously encompasses the different particular forms of human evolutionary research could help scholars and scientists envision their own specialized areas...... of research as contributions to a coherent, collective research program. This article argues that a mature biocultural paradigm needs to be informed by at least 7 major research clusters: (a) gene-culture coevolution; (b) human life history theory; (c) evolutionary social psychology; (d) anthropological...
Improving nanocavity switching using Fano resonances in photonic crystal structures
DEFF Research Database (Denmark)
Heuck, Mikkel; Kristensen, Philip Trøst; Elesin, Yuriy
2013-01-01
We present a simple design for achieving Fano resonances in photonic crystal coupled waveguide-cavity structures. A coupled mode theory analysis shows an order of magnitude reduction in switching energy compared to conventional Lorentz resonances....
Quantifying the Adaptive Cycle.
Directory of Open Access Journals (Sweden)
David G Angeler
Full Text Available The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994-2011 data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and adaptation provides opportunities to cope with the intricacies and uncertainties associated with fast ecological change, driven by shifting system controls. Ultimately, combining traditional ecological paradigms with heuristics of complex system dynamics using quantitative approaches may help refine ecological theory and improve our understanding of the resilience of ecosystems.
Quantifying the adaptive cycle
Angeler, David G.; Allen, Craig R.; Garmestani, Ahjond S.; Gunderson, Lance H.; Hjerne, Olle; Winder, Monika
2015-01-01
The adaptive cycle was proposed as a conceptual model to portray patterns of change in complex systems. Despite the model having potential for elucidating change across systems, it has been used mainly as a metaphor, describing system dynamics qualitatively. We use a quantitative approach for testing premises (reorganisation, conservatism, adaptation) in the adaptive cycle, using Baltic Sea phytoplankton communities as an example of such complex system dynamics. Phytoplankton organizes in recurring spring and summer blooms, a well-established paradigm in planktology and succession theory, with characteristic temporal trajectories during blooms that may be consistent with adaptive cycle phases. We used long-term (1994–2011) data and multivariate analysis of community structure to assess key components of the adaptive cycle. Specifically, we tested predictions about: reorganisation: spring and summer blooms comprise distinct community states; conservatism: community trajectories during individual adaptive cycles are conservative; and adaptation: phytoplankton species during blooms change in the long term. All predictions were supported by our analyses. Results suggest that traditional ecological paradigms such as phytoplankton successional models have potential for moving the adaptive cycle from a metaphor to a framework that can improve our understanding how complex systems organize and reorganize following collapse. Quantifying reorganization, conservatism and adaptation provides opportunities to cope with the intricacies and uncertainties associated with fast ecological change, driven by shifting system controls. Ultimately, combining traditional ecological paradigms with heuristics of complex system dynamics using quantitative approaches may help refine ecological theory and improve our understanding of the resilience of ecosystems.
Fischer, Sebastian; Freund, Philipp Alexander
2014-01-01
The Adaption-Innovation Inventory (AII), originally developed by Kirton (1976), is a widely used self-report instrument for measuring problem-solving styles at work. The present study investigates how scores on the AII are affected by different response styles. Data are collected from a combined sample (N = 738) of students, employees, and…
Advances in magnetic resonance 5
Waugh, John S
2013-01-01
Advances in Magnetic Resonance, Volume 5 deals with the interpretation of ESR spectra and provides descriptions of experimental apparatus. This book discusses the halogen hyperfine interactions; organic radicals in single crystals; pulsed-Fourier-transform nuclear magnetic resonance spectrometer; and inhomogenizer and decoupler. The spectrometers for multiple-pulse NMR; weak collision theory of relaxation in the rotating frame; and spin Hamiltonian for the electron spin resonance of irradiated organic single crystals are also deliberated. This text likewise covers the NMR in helium three and m
Advances in magnetic resonance 1
Waugh, John S
2013-01-01
Advances in Magnetic Resonance, Volume 1, discusses developments in various areas of magnetic resonance. The subject matter ranges from original theoretical contributions through syntheses of points of view toward series of phenomena to critical and painstaking tabulations of experimental data. The book contains six chapters and begins with a discussion of the theory of relaxation processes. This is followed by separate chapters on the development of magnetic resonance techniques for studying rate processes in chemistry and the application of these techniques to various problems; the geometri
Coupled-resonator optical waveguides
DEFF Research Database (Denmark)
Raza, Søren; Grgic, Jure; Pedersen, Jesper Goor
2010-01-01
Coupled-resonator optical waveguides hold potential for slow-light propagation of optical pulses. The dispersion properties may adequately be analyzed within the framework of coupled-mode theory. We extend the standard coupled-mode theory for such structures to also include complex......-valued parameters which allows us to analyze the dispersion properties also in presence of finite Q factors for the coupled resonator states. Near the band-edge the group velocity saturates at a finite value vg/c µ p1/Q while in the band center, the group velocity is unaffected by a finite Q factor as compared...
International Nuclear Information System (INIS)
Lind, P.
1993-02-01
The completeness properties of the discrete set of bound state, virtual states and resonances characterizing the system of a single nonrelativistic particle moving in a central cutoff potential is investigated. From a completeness relation in terms of these discrete states and complex scattering states one can derive several Resonant State Expansions (RSE). It is interesting to obtain purely discrete expansion which, if valid, would significantly simplify the treatment of the continuum. Such expansions can be derived using Mittag-Leffler (ML) theory for a cutoff potential and it would be nice to see if one can obtain the same expansions starting from an eigenfunction theory that is not restricted to a finite sphere. The RSE of Greens functions is especially important, e.g. in the continuum RPA (CRPA) method of treating giant resonances in nuclear physics. The convergence of RSE is studied in simple cases using square well wavefunctions in order to achieve high numerical accuracy. Several expansions can be derived from each other by using the theory of analytic functions and one can the see how to obtain a natural discretization of the continuum. Since the resonance wavefunctions are oscillating with an exponentially increasing amplitude, and therefore have to be interpreted through some regularization procedure, every statement made about quantities involving such states is checked by numerical calculations.Realistic nuclear wavefunctions, generated by a Wood-Saxon potential, are used to test also the usefulness of RSE in a realistic nuclear calculation. There are some fundamental differences between different symmetries of the integral contour that defines the continuum in RSE. One kind of symmetry is necessary to have an expansion of the unity operator that is idempotent. Another symmetry must be used if we want purely discrete expansions. These are found to be of the same form as given by ML. (29 refs.)
Liongue, Clifford; John, Liza B; Ward, Alister
2011-01-01
Adaptive immunity, involving distinctive antibody- and cell-mediated responses to specific antigens based on "memory" of previous exposure, is a hallmark of higher vertebrates. It has been argued that adaptive immunity arose rapidly, as articulated in the "big bang theory" surrounding its origins, which stresses the importance of coincident whole-genome duplications. Through a close examination of the key molecules and molecular processes underpinning adaptive immunity, this review suggests a less-extreme model, in which adaptive immunity emerged as part of longer evolutionary journey. Clearly, whole-genome duplications provided additional raw genetic materials that were vital to the emergence of adaptive immunity, but a variety of other genetic events were also required to generate some of the key molecules, whereas others were preexisting and simply co-opted into adaptive immunity.
International Nuclear Information System (INIS)
Friedrich, Harald
2013-01-01
Written by the author of the widely acclaimed textbook. Theoretical Atomic Physics Includes sections on quantum reflection, tunable Feshbach resonances and Efimov states. Useful for advanced students and researchers. This book presents a concise and modern coverage of scattering theory. It is motivated by the fact that experimental advances have shifted and broadened the scope of applications where concepts from scattering theory are used, e.g. to the field of ultracold atoms and molecules, which has been experiencing enormous growth in recent years, largely triggered by the successful realization of Bose-Einstein condensates of dilute atomic gases in 1995. In the present treatment, special attention is given to the role played by the long-range behaviour of the projectile-target interaction, and a theory is developed, which is well suited to describe near-threshold bound and continuum states in realistic binary systems such as diatomic molecules or molecular ions. The level of abstraction is kept as low as at all possible, and deeper questions related to mathematical foundations of scattering theory are passed by. The book should be understandable for anyone with a basic knowledge of nonrelativistic quantum mechanics. It is intended for advanced students and researchers, and it is hoped that it will be useful for theorists and experimentalists alike.
Von Esch, Kerry Soo; Kavanagh, Sarah Schneider
2018-01-01
Preparing classroom teachers to teach English Learner (EL) students continues to challenge teacher educators. This article argues for EL teaching work to be situated within theories of professional learning that focus on developing teachers who can flexibly and innovatively integrate EL instructional practice into content area teaching. We propose…
A review on biological adaptation: with applications in engineering science
Directory of Open Access Journals (Sweden)
LiMin Luo
2014-06-01
Full Text Available Biological adaptation refers to that organisms change themselves at morphological, physiological, behavioral and molecular level to better survive in a changing environment. It includes phenotype adaptation and molecular adaptation. Biological adaptation is a driving force of evolution. Biological adaptation was described from Darwinian theory of evolution to the theory of molecular evolution in present paper. Adaptive control and adaptive filtering were briefly described also.
Neutron resonance spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Gunsing, F
2005-06-15
The present document has been written in order to obtain the diploma 'Habilitation a Diriger des Recherches'. Since this diploma is indispensable to supervise thesis students, I had the intention to write a document that can be useful for someone starting in the field of neutron resonance spectroscopy. Although the here described topics are already described elsewhere, and often in more detail, it seemed useful to have most of the relevant information in a single document. A general introduction places the topic of neutron-nucleus interaction in a nuclear physics context. The large variations of several orders of magnitude in neutron-induced reaction cross sections are explained in terms of nuclear level excitations. The random character of the resonances make nuclear model calculation predictions impossible. Then several fields in physics where neutron-induced reactions are important and to which I have contributed in some way or another, are mentioned in a first synthetic chapter. They concern topics like parity nonconservation in certain neutron resonances, stellar nucleosynthesis by neutron capture, and data for nuclear energy applications. The latter item is especially important for the transmutation of nuclear waste and for alternative fuel cycles. Nuclear data libraries are also briefly mentioned. A second chapter details the R-matrix theory. This formalism is the foundation of the description of the neutron-nucleus interaction and is present in all fields of neutron resonance spectroscopy. (author)
Esposito, A.; Polosa, A.D.
2016-01-01
Multiquark resonances are undoubtedly experimentally observed. The number of states and the amount of details on their properties has been growing over the years. It is very recent the discovery of two pentaquarks and the confirmation of four tetraquarks, two of which had not been observed before. We mainly review the theoretical understanding of this sector of particle physics phenomenology and present some considerations attempting a coherent description of the so called X and Z resonances. The prominent problems plaguing theoretical models, like the absence of selection rules limiting the number of states predicted, motivate new directions in model building. Data are reviewed going through all of the observed resonances with particular attention to their common features and the purpose of providing a starting point to further research.
Gerweck, L E; Kozin, S V; Stocks, S J
1999-01-01
The accumulation and toxicity of the weak base doxorubicin has been investigated as a function of extracellular pH, intracellular pH and the cellular pH gradient in cells previously cultured under normal (pH 7.4) and low-pH (6.8) conditions. Low-pH-adapted cells exhibit transmembrane pH gradients which substantially differ from normal cells at the same extracellular pH. No relationship was obtained between intracellular pH and the uptake or toxicity of doxorubicin in the two cell types. In co...
DEFF Research Database (Denmark)
Enemark, Søren; Santos, Ilmar F.
2016-01-01
Helical pseudoelastic shape memory alloy (SMA) springs are integrated into a dynamic system consisting of a rigid rotor supported by passive magnetic bearings. The aim is to determine the utility of SMAs for vibration attenuation via their mechanical hysteresis, and for adaptation of the dynamic...... nonlinear coupled dynamics of the rotor-bearing system. The nonlinear forces from the thermomechanical shape memory alloy springs and from the passive magnetic bearings are coupled to the rotor and bearing housing dynamics. The equations of motion describing rotor tilt and bearing housing lateral motion...
Resonant vibration control of rotating beams
DEFF Research Database (Denmark)
Svendsen, Martin Nymann; Krenk, Steen; Høgsberg, Jan Becker
2011-01-01
Rotatingstructures,like e.g.wind turbine blades, may be prone to vibrations associated with particular modes of vibration. It is demonstrated, how this type of vibrations can be reduced by using a collocated sensor–actuator system, governed by a resonant controller. The theory is here demonstrated...... modal connectivity, only very limited modal spill-over is generated. The controller acts by resonance and therefore has only a moderate energy consumption, and successfully reduces modal vibrations at the resonance frequency....
Stark resonances: asymptotics and distributional Borel sum
International Nuclear Information System (INIS)
Caliceti, E.; Grecchi, V.; Maioli, M.
1993-01-01
We prove that the Stark effect perturbation theory of a class of bound states uniquely determines the position and the width of the resonances by Distributional Borel Sum. In particular the small field asymptotics of the width is uniquely related to the large order asymptotics of the perturbation coefficients. Similar results apply to all the ''resonances'' of the anharmonic and double well oscillators. (orig.)
Hemispherical Resonator Gyro: an IRU for Cassini
Litty, Edward C.; Gresham, Lennor L.; Toole, Patrick A.; Beisecker, Debra A.
1996-10-01
The JPL Inertial Reference Unit (IRU) is the single most sophisticated assembly on the Cassini spacecraft. At the core of the IRU is the state-of-the-art, Litton Hemispherical Resonator Gyro (HRG). Launched in October 1997, Cassini's trajectory utilizes gravity assist maneuvers around Venus (two), Earth, and Jupiter over a seven year period, arriving at Saturn in June 2004. Its tour of the Saturnian system will last an additional four years. Although the Stellar Reference Unit (SRU) provides the ultimate reference for the spacecraft Attitude and Articulation Control System (AACS) and can be used to control the spacecraft under benign conditions, the Cassini IRU is essential during maneuvers and fault recovery operations, and for precision attitude stabilization during science data acquisition. Therefore, IRU reliability over the long Cassini mission is a critical concern. Following an extensive evaluation of possible alternatives, the Hemispherical Resonator Gyro (HRG) based IRU developed by Litton Guidance and Control Systems, was chosen for the Cassini mission. The HRG is an attitude rate sensor that has no physical wear-out mechanisms. Based on a principle first described by G. H. Bryan (1890) in his paper, 'On Beats in the Vibrations of a Revolving Cylinder or Bell', the HRG is created by vibrating a quartz resonator. This paper discusses the theory and modifications required to the design of the standard Space Inertial Reference Unit to adapt it to meet the requirements of the Cassini mission and the AACS interface. The Cassini mission is the first use of an IRU for a deep space planetary mission that does not use a spun-mass sensor.
DEFF Research Database (Denmark)
Stein, Irene F.; Stelter, Reinhard
2011-01-01
Communication theory covers a wide variety of theories related to the communication process (Littlejohn, 1999). Communication is not simply an exchange of information, in which we have a sender and a receiver. This very technical concept of communication is clearly outdated; a human being...... is not a data processing device. In this chapter, communication is understood as a process of shared meaning-making (Bruner, 1990). Human beings interpret their environment, other people, and themselves on the basis of their dynamic interaction with the surrounding world. Meaning is essential because people...... ascribe specific meanings to their experiences, their actions in life or work, and their interactions. Meaning is reshaped, adapted, and transformed in every communication encounter. Furthermore, meaning is cocreated in dialogues or in communities of practice, such as in teams at a workplace or in school...
Resonance | Indian Academy of Sciences
Indian Academy of Sciences (India)
Home; Resonance. 404! error. The page your are looking for can not be found! Please check the link or use the navigation bar at the top. YouTube; Twitter; Facebook; Blog. Academy News. IAS Logo. Theory Of Evolution. Posted on 23 January 2018. Joint Statement by the Three Science Academies of India on the teaching ...
Acoustic Resonance in School Hallways
Bucki, Elliot; Nagle, Matthew; Smith, Pearson; Taylor, Ken
2010-03-01
This paper takes the theory of acoustic standing waves for air columns and applies it to school hallways. By utilizing an audio generator and power amplifier/speaker the authors set up an experiment in a school hallway and studied the resonant patterns created for a range of driving frequencies. Data describing the various mode structures are presented.
DEFF Research Database (Denmark)
Avery, John Scales; Rettrup, Sten; Avery, James Emil
In theoretical physics, theoretical chemistry and engineering, one often wishes to solve partial differential equations subject to a set of boundary conditions. This gives rise to eigenvalue problems of which some solutions may be very difficult to find. For example, the problem of finding...... in such problems can be much reduced by making use of symmetry-adapted basis functions. The conventional method for generating symmetry-adapted basis sets is through the application of group theory, but this can be difficult. This book describes an easier method for generating symmetry-adapted basis sets...
Resonance – Journal of Science Education | Indian Academy of ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 8. Complex Systems: An Introduction - Information Theory, Chaos Theory and Computational Complexity. V K Wadhawan. General Article Volume 14 Issue 8 August 2009 pp 761-781 ...
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Lee, Dorothy B; Faget, Maxime A
1956-01-01
A modified method of Van Driest's flat-plate theory for turbulent boundary layer has been found to simplify the calculation of local skin-friction coefficients which, in turn, have made it possible to obtain through Reynolds analogy theoretical turbulent heat-transfer coefficients in the form of Stanton number. A general formula is given and charts are presented from which the modified method can be solved for Mach numbers 1.0 to 12.0, temperature ratios 0.2 to 6.0, and Reynolds numbers 0.2 times 10 to the 6th power to 200 times 10 to the 6th power.
Friedrich, Harald
2016-01-01
This corrected and updated second edition of "Scattering Theory" presents a concise and modern coverage of the subject. In the present treatment, special attention is given to the role played by the long-range behaviour of the projectile-target interaction, and a theory is developed, which is well suited to describe near-threshold bound and continuum states in realistic binary systems such as diatomic molecules or molecular ions. It is motivated by the fact that experimental advances have shifted and broadened the scope of applications where concepts from scattering theory are used, e.g. to the field of ultracold atoms and molecules, which has been experiencing enormous growth in recent years, largely triggered by the successful realization of Bose-Einstein condensates of dilute atomic gases in 1995. The book contains sections on special topics such as near-threshold quantization, quantum reflection, Feshbach resonances and the quantum description of scattering in two dimensions. The level of abstraction is k...
DEFF Research Database (Denmark)
Hjelholt, Morten; Jensen, Tina Blegind
2015-01-01
IT projects are often complex arrangements of technological components, social actions, and organizational transformation that are difficult to manage in practice. This paper takes an analytical discourse perspective to explore the process of legitimizing IT projects. We introduce the concept of ...... as part of a feedback loop to re-attach the localized IT project to the broader national discourse. The paper concludes with reflections on how to actively build on resonating statements as a strategic resource for legitimizing IT projects...... of resonating statements to highlight how central actors navigate in various discourses over time. Particularly, the statements and actions of an IT project manager are portrayed to show how individuals can legitimize actions by connecting statements to historically produced discourses. The case study...... of an IT project in a Danish local government spans a two-year time period and demonstrates a double-loop legitimization process. First, resonating statements are produced to localize a national IT initiative to support the specificity of a local government discourse. Second, the resonating statements are used...
Leavey, Sean; Rae, Katherine; Murray, Adam; Courtial, Johannes
2012-09-01
Autostereograms, or "Magic Eye" pictures, are repeating patterns designed to give the illusion of depth. Here we discuss optical resonators that create light patterns which, when viewed from a suitable position by a monocular observer, are autostereograms of the three-dimensional shape of one of the mirror surfaces.
Winter School on Coding Theory
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 8; Issue 8. Winter School on Coding Theory. Information and Announcements Volume 8 Issue 8 August 2003 pp 111-111. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/008/08/0111-0111. Resonance ...
DEFF Research Database (Denmark)
Clemmensen, Torkil; Kaptelinin, Victor; Nardi, Bonnie
2016-01-01
This paper reports a study of the use of activity theory in human–computer interaction (HCI) research. We analyse activity theory in HCI since its first appearance about 25 years ago. Through an analysis and meta-synthesis of 109 selected HCI activity theory papers, we created a taxonomy of 5...... different ways of using activity theory: (1) analysing unique features, principles, and problematic aspects of the theory; (2) identifying domain-specific requirements for new theoretical tools; (3) developing new conceptual accounts of issues in the field of HCI; (4) guiding and supporting empirical...... analyses of HCI phenomena; and (5) providing new design illustrations, claims, and guidelines. We conclude that HCI researchers are not only users of imported theory, but also theory-makers who adapt and develop theory for different purposes....
Review on resonance cone fields
International Nuclear Information System (INIS)
Ohnuma, Toshiro.
1980-02-01
Resonance cone fields and lower hybrid heating are reviewed in this report. The resonance cone fields were reported by Fisher and Gould, and they proposed the use of the measurement of resonance cones and structure as a diagnostic tool to determine the plasma density and electron temperature in magnetoplasma. After the resonance cone, a wave-like disturbance persists. Ohnuma et al. have measured bending, reflection and ducting of resonance cones in detail. The thermal modes in inhomogeneous magnetoplasma were seen. The reflection of thermal mode near an electron plasma frequency layer and an insulating plate has been observed. The non-linear effects of resonance cones is reported. Monochromatic electron beam produces the noise of broad band whistler mode. Lower hybrid waves have been the subject of propagation from the edge of plasma to the lower hybrid layer. Linear lower hybrid waves were studied. The lower hybrid and ion acoustic waves radiated from a point source were observed. The parametric decay of finite-extent, cold electron plasma waves was studied. The lower hybrid cone radiated from a point source going along magnetic field lines was observed. Several experimental data on the lower hybrid heating in tokamak devices have been reported. The theories on resonance cones and lower hybrid waves are introduced in this report. (Kato, T.)
Theoretical foundations of electron spin resonance
Harriman, John E
2013-01-01
Theoretical Foundations of Electron Spin Resonance deals with the theoretical approach to electron paramagnetic resonance. The book discusses electron spin resonance in applications related to polyatomic, probably organic, free radicals in condensed phases. The book also focuses on essentially static phenomena, that is, the description and determination of stationary-state energy levels. The author reviews the Dirac theory of the electron in which a four-component wave function is responsible for the behavior of the electron. The author then connects this theory with the nonrelativistic wave f
Multimode vibrational couplings in resonant positron annihilation.
d'A Sanchez, Sergio; Lima, Marco A P; Varella, Márcio T do N
2011-09-02
The mechanisms for multimode vibrational couplings in resonant positron annihilation are not well understood. We show that these resonances can arise from positron-induced distortions of the potential energy surface (target response to the positron field). Though these distortions can transfer energy into single- and multiquantum vibrations, they have so far been disregarded as a pathway to resonant annihilation. We also compare the existing annihilation theories and show that the currently accepted model can be cast as a special case of the Feshbach annihilation theory.
Optofluidic ring resonator dye lasers
Sun, Yuze; Suter, Jonathan D.; Fan, Xudong
2010-02-01
We overview the recent progress on optofluidic ring resonator (OFRR) dye lasers developed in our research group. The fluidics and laser cavity design can be divided into three categories: capillary optofluidic ring resonator (COFRR), integrated cylindrical optofluidic ring resonator (ICOFRR), and coupled optofluidic ring resonator (CpOFRR). The COFRR dye laser is based on a micro-sized glass capillary with a wall thickness of a few micrometers. The capillary circular cross-section forms the ring resonator and supports the whispering gallery modes (WGMs) that interact evanescently with the gain medium in the core. The laser cavity structure is versatile to adapt to the gain medium of any refractive index. Owing to the high Q-factor (>109), the lasing threshold of 25 nJ/mm2 is achieved. Besides directly pump the dye molecules, lasing through fluorescence resonance energy transfer (FRET) between the donor and acceptor dye molecules is also studied in COFRR laser. The energy transfer process can be further controlled by designed DNA scaffold labeled with donor/acceptor molecules. The ICOFRR dye laser is based on a cylindrical ring resonator fused onto the inner surface of a thick walled glass capillary. The structure has robust mechanical strength to sustain rapid gain medium circulation. The CpOFRR utilizes a cylindrical ring resonator fused on the inner surface of the COFRR capillary. Since the capillary wall is thin, the individual WGMs of the cylindrical ring resonator and the COFRR couples strongly and forms Vernier effect, which provides a way to generate a single mode dye laser.
Resonant behavior of dielectric objects (electrostatic resonances).
Fredkin, D R; Mayergoyz, I D
2003-12-19
Resonant behavior of dielectric objects occurs at certain frequencies for which the object permittivity is negative and the free-space wavelength is large in comparison with the object dimensions. Unique physical features of these resonances are studied and a novel technique for the calculation of resonance values of permittivity, and hence resonance frequencies, is proposed. Scale invariance of resonance frequencies, unusually strong orthogonality properties of resonance modes, and a two-dimensional phenomenon of "twin" spectra are reported. The paper concludes with brief discussions of optical controllability of these resonances in semiconductor nanoparticles and a plausible, electrostatic resonance based, mechanism for nucleation and formation of ball lightning.
Adaptive filtering prediction and control
Goodwin, Graham C
2009-01-01
Preface1. Introduction to Adaptive TechniquesPart 1. Deterministic Systems2. Models for Deterministic Dynamical Systems3. Parameter Estimation for Deterministic Systems4. Deterministic Adaptive Prediction5. Control of Linear Deterministic Systems6. Adaptive Control of Linear Deterministic SystemsPart 2. Stochastic Systems7. Optimal Filtering and Prediction8. Parameter Estimation for Stochastic Dynamic Systems9. Adaptive Filtering and Prediction10. Control of Stochastic Systems11. Adaptive Control of Stochastic SystemsAppendicesA. A Brief Review of Some Results from Systems TheoryB. A Summary o
Hybrid Adaptive Flight Control with Model Inversion Adaptation
Nguyen, Nhan
2011-01-01
This study investigates a hybrid adaptive flight control method as a design possibility for a flight control system that can enable an effective adaptation strategy to deal with off-nominal flight conditions. The hybrid adaptive control blends both direct and indirect adaptive control in a model inversion flight control architecture. The blending of both direct and indirect adaptive control provides a much more flexible and effective adaptive flight control architecture than that with either direct or indirect adaptive control alone. The indirect adaptive control is used to update the model inversion controller by an on-line parameter estimation of uncertain plant dynamics based on two methods. The first parameter estimation method is an indirect adaptive law based on the Lyapunov theory, and the second method is a recursive least-squares indirect adaptive law. The model inversion controller is therefore made to adapt to changes in the plant dynamics due to uncertainty. As a result, the modeling error is reduced that directly leads to a decrease in the tracking error. In conjunction with the indirect adaptive control that updates the model inversion controller, a direct adaptive control is implemented as an augmented command to further reduce any residual tracking error that is not entirely eliminated by the indirect adaptive control.
Hureau, Christelle; Groni, Sihem; Guillot, Régis; Blondin, Geneviève; Duboc, Carole; Anxolabéhère-Mallart, Elodie
2008-10-20
The two pentadentate amino-pyridine ligands L5(2) and L5(3) (L5(2) and L5(3) stand for the N-methyl-N,N',N'-tris(2-pyridylmethyl)ethane-1,2-diamine and the N-methyl-N,N',N'-tris(2-pyridylmethyl)propane-1,3-diamine, respectively) were used to synthesize four mononuclear Mn(II) complexes, namely [(L5(2))MnCl](PF6) (1(PF6)), [(L5(3))MnCl](PF6) (2(PF6)), [(L5(2))Mn(OH2)](BPh4)2 (3(BPh4)2), and [(L5(3))Mn(OH2)](BPh4)2 (4(BPh4)2). The X-ray diffraction studies revealed different configurations for the ligand L5(n) (n = 2, 3) depending on the sixth exogenous ligand and/or the counterion. Solid state high-field electron paramagnetic resonance spectra were recorded on complexes 1-4 as on previously described mononuclear Mn(II) systems with tetra- or hexadentate amino-pyridine ligands. Positive and negative axial zero-field splitting (ZFS) parameters D were determined whose absolute values ranged from 0.090 to 0.180 cm(-1). Density-functional theory calculations were performed unraveling that, in contrast with chloro systems, the spin-spin and spin-orbit coupling contributions to the D-parameter are comparable for mixed N,O-coordination sphere complexes.
Enhancement of Stochastic Resonance Using Optimization Theory
National Research Council Canada - National Science Library
Wu, Xingxing; Jiang, Zhong-Ping; Repperger, Daniel W; Guo, Yi
2006-01-01
.... The further improvement of the maximal normalized power norm of the bistable double-well dynamic system with white Gaussian noise input can be converted to an optimization problem with constraints...
Double-resonance methods in gases, with application to OCS
Hoyng, P.; Dijkerman, H.A.; Ruitenberg, G.
We present a systematic derivation of and a few corrections to the theory on double resonance given by Autler and Townes. We discuss the range of validity of this theory and show its relation with the theory formulated by Di Giacomo. In addition, a critical comparison of both theories with
Parametric resonance in concrete beam-columns
Directory of Open Access Journals (Sweden)
Mamta R. Sharma
Full Text Available A dynamic instability, called parametric resonance, is exhibited by undampedelastic beam-columns when under the action of pulsating axial force. The scope of the existing theory of parametric resonance is restricted to physically linear beam-columns undergoing finite lateral displacements. In this Paper, the dynamic behaviour of physically nonlinear elastic cracked concrete beam-columns under pulsating axial force and constant lateral force is investigated. The constitutive equations derived earlier by Authors in the form of force-displacement relations are employed here to formulate equations of motion of the SDOF cantilever with mass lumped at its free end. The expected phenomenon of parametric resonance is exhibited in the form of regular subharmonic resonance at about the frequency ratio of two. Resonance peaks broaden with increase in pulsating force. Like damping, physical nonlinearity is also predicted to stabilize the dynamic response at resonance frequencies. In some particular statically unstable conditions, the loss of dynamic stability is shown to occur by divergence. Unexpectedly, similar phenomenon of parametric resonance is exhibited by these physically nonlinear beam-columns undergoing even small lateral displacements. The contribution made to the theory of parametric resonance and the potential relevance of the proposed theory to design of concrete beam-columns is discussed.
McGill, Anne-Thea
2014-01-01
The medical, research and general community is unable to effect significantly decreased rates of central obesity and related type II diabetes mellitus (TIIDM), cardiovascular disease (CVD) and cancer. All conditions seem to be linked by the concept of the metabolic syndrome (MetS), but the underlying causes are not known. MetS markers may have been mistaken for causes, thus many treatments are destined to be suboptimal. The current paper aims to critique current paradigms, give explanations for their persistence, and to return to first principles in an attempt to determine and clarify likely causes of MetS and obesity related comorbidities. A wide literature has been mined, study concepts analysed and the basics of human evolution and new biochemistry reviewed. A plausible, multifaceted composite unifying theory is formulated. The basis of the theory is that the proportionately large, energy-demanding human brain may have driven co-adaptive mechanisms to provide, or conserve, energy for the brain. A 'dual system' is proposed. 1) The enlarged, complex cortico-limbic-striatal system increases dietary energy by developing strong neural self-reward/motivation pathways for the acquisition of energy dense food, and (2) the nuclear factor-erythroid 2-related factor 2 (NRF2) cellular protection system amplifies antioxidant, antitoxicant and repair activity by employing plant chemicals, becoming highly energy efficient in humans. The still-evolving, complex human cortico-limbic-striatal system generates strong behavioural drives for energy dense food procurement, including motivating agricultural technologies and social system development. Addiction to such foods, leading to neglect of nutritious but less appetizing 'common or garden' food, appears to have occurred. Insufficient consumption of food micronutrients prevents optimal human NRF2 function. Inefficient oxidation of excess energy forces central and non-adipose cells to store excess toxic lipid. Oxidative stress and
Indian Academy of Sciences (India)
IAS Admin
He spends several months in India visiting schools, colleges and universities. He enjoys teaching mathematics and statistics at all levels. He loves Indian classical and folk music. This issue of Resonance features Joseph Leonard. Doob, who played a critical role in the devel- opment of probability theory in the world from.
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 3; Issue 4. The Theory of Probability. Andrei Nikolaevich Kolmogorov. Classics Volume 3 Issue 4 April 1998 pp 103-112. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/003/04/0103-0112. Author Affiliations.
Probability Theory Without Tears!
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 1; Issue 2. Probability Theory Without Tears! S Ramasubramanian. Book Review Volume 1 Issue 2 February 1996 pp 115-116. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/001/02/0115-0116 ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 18; Issue 9. Littlewood and Number Theory. M Ram Murty. General Article Volume 18 Issue 9 September 2013 pp 789-798. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/018/09/0789-0798. Keywords.
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 2; Issue 12. The Theory of Positrons. Richard P Feynman. Classics Volume 2 Issue 12 December 1997 pp 107-107. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/002/12/0107-0107. Author Affiliations.
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 11; Issue 4. General Theory of Relativity – The Power of Speculative Thought. Asit Banerjee. General Article Volume 11 Issue 4 April 2006 pp 45-55. Fulltext. Click here to view fulltext PDF. Permanent link:
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 9; Issue 3. Introduction to Game Theory. S Ramasubramanian. Book Review Volume 9 Issue 3 March 2004 pp 81-81. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/009/03/0081-0081. Author Affiliations.
Indian Academy of Sciences (India)
IAS Admin
1004. RESONANCE │ November 2013. Page 2. 1005. RESONANCE │ November 2013. Page 3. 1006. RESONANCE │ November 2013. Page 4. 1007. RESONANCE │ November 2013. Page 5. 1008. RESONANCE │ November 2013. Page 6. 1009. RESONANCE │ November 2013. Page 7. 1010. RESONANCE ...
International Nuclear Information System (INIS)
Lee, S.Y.
1993-01-01
We found that the perturbed spin tune due to the imperfection resonance plays an important role in beam depolarization at snake resonances. We also found that even order snake resonances exist in the overlapping intrinsic and imperfection resonances. Due to the perturbed spin tune shift of imperfection resonances, each snake resonance splits into two
Ince-Strutt stability charts for ship parametric roll resonance in irregular waves
Zhang, Xiao; Yang, He-zhen; Xiao, Fei; Xu, Pei-ji
2017-08-01
Ince-Strutt stability chart of ship parametric roll resonance in irregular waves is conducted and utilized for the exploration of the parametric roll resonance in irregular waves. Ship parametric roll resonance will lead to large amplitude roll motion and even wreck. Firstly, the equation describing the parametric roll resonance in irregular waves is derived according to Grim's effective theory and the corresponding Ince-Strutt stability charts are obtained. Secondly, the differences of stability charts for the parametric roll resonance in irregular and regular waves are compared. Thirdly, wave phases and peak periods are taken into consideration to obtain a more realistic sea condition. The influence of random wave phases should be taken into consideration when the analyzed points are located near the instability boundary. Stability charts for different wave peak periods are various. Stability charts are helpful for the parameter determination in design stage to better adapt to sailing condition. Last, ship variables are analyzed according to stability charts by a statistical approach. The increase of the metacentric height will help improve ship stability.
Time reversal symmetry breaking effects in resonant nuclear reactions
International Nuclear Information System (INIS)
Feshbach, H.; Hussein, M.S.; Kerman, A.K.
1995-01-01
We incorporate time reversal symmetry breaking (TRSB) effects into the theory of compound nuclear reactions. We show that the only meaningful test of TRSB in the overlapping resonances regime is through the study of cross-section correlations. The effect is channel-dependent. In the isolated resonance regime, we employ K-matrix theory to show the impact of TRSB using the fact that when only one eigen-channel participates in populating and depopulating the compound resonance. (orig.)
DEFF Research Database (Denmark)
Wæver, Ole
2009-01-01
Kenneth N. Waltz's 1979 book, Theory of International Politics, is the most influential in the history of the discipline. It worked its effects to a large extent through raising the bar for what counted as theoretical work, in effect reshaping not only realism but rivals like liberalism and refle......Kenneth N. Waltz's 1979 book, Theory of International Politics, is the most influential in the history of the discipline. It worked its effects to a large extent through raising the bar for what counted as theoretical work, in effect reshaping not only realism but rivals like liberalism...... and reflectivism. Yet, ironically, there has been little attention to Waltz's very explicit and original arguments about the nature of theory. This article explores and explicates Waltz's theory of theory. Central attention is paid to his definition of theory as ‘a picture, mentally formed' and to the radical anti...
Role of vibrational dynamics in resonant positron annihilation on molecules.
Jones, A C L; Danielson, J R; Natisin, M R; Surko, C M
2013-05-31
Vibrational Feshbach resonances are dominant features of positron annihilation for incident positron energies in the range of the molecular vibrations. Studies in relatively small molecules are described that elucidate the role of intramolecular vibrational energy redistribution into near-resonant multimode states, and the subsequent coupling of these modes to the positron continuum, in suppressing or enhancing these resonances. The implications for annihilation in other molecular species, and the necessary ingredients of a more complete theory of resonant positron annihilation, are discussed.
Nuclear theory. 1998 progress report
International Nuclear Information System (INIS)
1998-01-01
Summaries of progress made on the following topics are given: (1) nonresonant contributions to inelastic N→Δ(1232) parity violation; (2) neutron distribution effects in elastic nuclear parity violation; (3) Wilson RG for scalar-plus-fermion field theories at finite density; (4) Perturbation theory for spin ladders using angular momentum coupled bases; (5) mean-field theory for spin ladders using angular momentum density; (6) finite temperature renormalization group effective potentials for the linear Sigma model; (7) negative-parity baryon resonances from lattice QCD; (8) the N→Δ electromagnetic transition amplitudes from QCD sum rules; and (9) higher nucleon resonances in exclusive reactions (γ, πN) on nuclei
Operatic adaptation of drama scripts: Femi Osofisan's A restless run ...
African Journals Online (AJOL)
This paper examines the process of adapting a drama script into an opera using an adapted work of a prominent playwright as focus with Hutcheon's theory of adaptation as our reference point. This paper uses the adapted work to analyze and judge the success of adaptation and also points out its short comings. In view of ...
Directory of Open Access Journals (Sweden)
Breno Sanvicente-Vieira
2012-01-01
Full Text Available BACKGROUND: Theory of mind (ToM is a field of social cognition that deals with the individual’s cognitive ability to interpret or infer the mental states of others based on previous knowledge. Recently, research has shown that this ability is compromised in patients with some psychopathologies, e.g., schizophrenia and autistic disorder. Investigators have also shown that deficits in ToM have impacts on social functioning and, consequently, on quality of life. Even though ToM studies have recently grown in number, some problems still remain (e.g., the difficulty of standardized tools to assess ToM in different languages. OBJECTIVES: To describe the translation and adaptation into Brazilian Portuguese of two of the most important and widely used ToM tasks, namely, the Theory of Mind Stories and the Hinting Task. METHOD: The process included the following steps: 1 translation; 2 production of a single translated version and review by specialists; 3 back-translation into English; 4 review by an English-speaking specialist; 5 adaptation of marked corrections; and 6 pilot application in a group representative of the target population (people with schizophrenia. RESULTS: A final translated version was obtained for each of the tasks. Both instruments were well understood by participants and can now be used in the Brazilian experimental setting. CONCLUSION: The availability of two major ToM tasks in Brazilian Portuguese facilitates the conduction of research on the topic in Brazil. In the future, this could help design clinical interventions aimed at people with social and cognitive difficulties.INTRODUÇÃO: A teoria da mente (theory of mind, ToM é um domínio da cognição social que se refere à habilidade cognitiva de interpretar ou inferir estados mentais de outras pessoas através de conhecimentos prévios. Recentemente, pesquisas têm mostrado que essa capacidade está comprometida em algumas psicopatologias, como esquizofrenia e autismo. Al
DEFF Research Database (Denmark)
Petersen, Kjell Yngve; Søndergaard, Karin; Kongshaug, Jesper
2015-01-01
Adaptive Lighting Adaptive lighting is based on a partial automation of the possibilities to adjust the colour tone and brightness levels of light in order to adapt to people’s needs and desires. IT support is key to the technical developments that afford adaptive control systems. The possibilities...... offered by adaptive lighting control are created by the ways that the system components, the network and data flow can be coordinated through software so that the dynamic variations are controlled in ways that meaningfully adapt according to people’s situations and design intentions. This book discusses...... differently into an architectural body. We also examine what might occur when light is dynamic and able to change colour, intensity and direction, and when it is adaptive and can be brought into interaction with its surroundings. In short, what happens to an architectural space when artificial lighting ceases...
Asymmetric fMRI adaptation reveals no evidence for mirror neurons in humans.
Lingnau, Angelika; Gesierich, Benno; Caramazza, Alfonso
2009-06-16
Neurons in macaque ventral premotor cortex and inferior parietal lobe discharge during both the observation and the execution of motor acts. It has been claimed that these so-called mirror neurons form the basis of action understanding by matching the visual input with the corresponding motor program (direct matching). Functional magnetic resonance imaging (fMRI) adaptation can be used to test the direct matching account of action recognition by determining whether putative mirror neurons show adaptation for repeated motor acts independently of whether they are observed or executed. An unambiguous test of the hypothesis requires that the motor acts be meaningless to ensure that any adaptation effect is directly because of movement recognition/motor execution and not contextually determined inferences. We found adaptation for motor acts that were repeatedly observed or repeatedly executed. We also found adaptation for motor acts that were first observed and then executed, as would be expected if a previously seen act primed the subsequent execution of that act. Crucially, we found no signs of adaptation for motor acts that were first executed and then observed. Failure to find cross-modal adaptation for executed and observed motor acts is not compatible with the core assumption of mirror neuron theory, which holds that action recognition and understanding are based on motor simulation.
DEFF Research Database (Denmark)
Jørgensen, Frances; Boer, Harry
2006-01-01
In this paper, data from a longitudinal case study in an organization attempting to adapt its internal work processes to changes in its external context are presented, analyzed and discussed. Specifically, functionally structured work teams in one department of a Danish production facility were...... on the proper alignment between the structuring of the work processes and characteristics of the external context (Lawrence & Lorsch, 1967) – it provides a unique opportunity to explore the adaptation process in practice. The paper contributes to the development of contingency theory by lending support...
Error adaptation in mental arithmetic.
Desmet, Charlotte; Imbo, Ineke; De Brauwer, Jolien; Brass, Marcel; Fias, Wim; Notebaert, Wim
2012-01-01
Until now, error and conflict adaptation have been studied extensively using simple laboratory tasks. A common finding is that responses slow down after errors. According to the conflict monitoring theory, performance should also improve after an error. However, this is usually not observed. In this study, we investigated whether the characteristics of the experimental paradigms normally used could explain this absence. More precisely, these paradigms have in common that behavioural adaptation has little room to be expressed. We therefore studied error and conflict adaptation effects in a task that encounters the richness of everyday life's behavioural adaptation--namely, mental arithmetic, where multiple solution strategies are available. In accordance with our hypothesis, we observed that post-error accuracy increases after errors in mental arithmetic. No support for conflict adaptation in mental arithmetic was found. Implications for current theories of conflict and error monitoring are discussed.
What Drives Business Model Adaptation?
DEFF Research Database (Denmark)
Saebi, Tina; Lien, Lasse B.; Foss, Nicolai Juul
2017-01-01
Business models change as managers not only innovate business models, but also engage in more mundane adaptation in response to external changes, such as changes in the level or composition of demand. However, little is known about what causes such business model adaptation. We employ threat......-rigidity as well as prospect theory to examine business model adaptation in response to external threats and opportunities. Additionally, drawing on the behavioural theory of the firm, we argue that the past strategic orientation of a firm creates path dependencies that influence the propensity of the firm...... to adapt its business model. We test our hypotheses on a sample of 1196 Norwegian companies, and find that firms are more likely to adapt their business model under conditions of perceived threats than opportunities, and that strategic orientation geared towards market development is more conducive...
Resonant primordial gravitational waves amplification
Directory of Open Access Journals (Sweden)
Chunshan Lin
2016-01-01
Full Text Available We propose a mechanism to evade the Lyth bound in models of inflation. We minimally extend the conventional single-field inflation model in general relativity (GR to a theory with non-vanishing graviton mass in the very early universe. The modification primarily affects the tensor perturbation, while the scalar and vector perturbations are the same as the ones in GR with a single scalar field at least at the level of linear perturbation theory. During the reheating stage, the graviton mass oscillates coherently and leads to resonant amplification of the primordial tensor perturbation. After reheating the graviton mass vanishes and we recover GR.
Email Adaptation for Conflict Handling
DEFF Research Database (Denmark)
Lee, Joyce Yi‐Hui; Panteli, Niki; Bülow, Anne Marie
2018-01-01
This paper explores the context of email‐based communication in anestablished but fragile, inter‐organisational partnership, which wasoften overlain with conflict. Drawing upon adaptation theory, thisstudy explores how participants adapt to the use of email to handleconflict. Extensive data were...... the leanness of email in managing conflict, we found that underthe described conflict situation the very leanness of emailwas appreciated and thus, exploited by those concerned tomanage the conflict situation. Specifically, we identified 4 keyconflict‐triggered adaptation strategies, namely......, interactionavoidance, disempowering, blame‐protection, and image‐shelteringthat drove the ways in which email was adapted to maintainorganisational partnerships under conflict....
Magnetic resonance and its applications
Chizhik, Vladimir I; Donets, Alexey V; Frolov, Vyacheslav V; Komolkin, Andrei V; Shelyapina, Marina G
2014-01-01
The book provides a basic understanding of the underlying theory, fundamentals and applications of magnetic resonance The book implies a few levels of the consideration (from simple to complex) of phenomena, that can be useful for different groups of readers The introductory chapter provides the necessary underpinning knowledge for newcomers to the methods The exposition of theoretical materials goes from initial to final formulas through detailed intermediate expressions.
Jovanka, Della Raymena; Setiawan, Denny
2013-01-01
This paper aimed to describe preschool age children's Theory of Mind, as a part of their cognitive development. Some factors that affect the children's Theory of Mind are parental talking, social economic background, parents' education, etc.The research participants are 82 preschool age children in South Jakarta, Indonesia. The method used in this paper was quasi experiment, adaptated from Sobel, Li, and Corriveau's method. The statistical data were examined by one way ANOVA. These data sugge...
Metaharmonic Lattice Point Theory
Freeden, Willi
2011-01-01
Metaharmonic Lattice Point Theory covers interrelated methods and tools of spherically oriented geomathematics and periodically reflected analytic number theory. The book establishes multi-dimensional Euler and Poisson summation formulas corresponding to elliptic operators for the adaptive determination and calculation of formulas and identities of weighted lattice point numbers, in particular the non-uniform distribution of lattice points. The author explains how to obtain multi-dimensional generalizations of the Euler summation formula by interpreting classical Bernoulli polynomials as Green
DEFF Research Database (Denmark)
Petersen, Kjell Yngve; Søndergaard, Karin; Kongshaug, Jesper
2015-01-01
Adaptive Lighting Adaptive lighting is based on a partial automation of the possibilities to adjust the colour tone and brightness levels of light in order to adapt to people’s needs and desires. IT support is key to the technical developments that afford adaptive control systems. The possibilities...... offered by adaptive lighting control are created by the ways that the system components, the network and data flow can be coordinated through software so that the dynamic variations are controlled in ways that meaningfully adapt according to people’s situations and design intentions. This book discusses...... the investigations of lighting scenarios carried out in two test installations: White Cube and White Box. The test installations are discussed as large-scale experiential instruments. In these test installations we examine what could potentially occur when light using LED technology is integrated and distributed...
Coherent and incoherent processes in resonant photoemission
Energy Technology Data Exchange (ETDEWEB)
Magnuson, M.; Karis, O.; Weinelt, M. [Uppsala Univ. (Sweden)] [and others
1997-04-01
In this contribution the authors present the distinction between coherent and incoherent processes in resonant photoemission. As a first step they determine whether an autoionization process is photoemission-like or Auger-like. The discussion is based on measurements for a weakly bonded adsorption system, Ar/Pt(111). This type of system is well adapted to investigate these effects since it yields distinctly shifted spectral features depending on the nature of the process. After this, the question of resonance photoemission in metallic systems is addressed. This is done in connection with measurements at the 2p edges for Ni metal. Ni has been one of the prototype systems for resonant photoemission. The resonances have been discussed in connection with the strong correlation and d-band localization effects in this system. Based on the results some general comments about the appearance of resonant effects in metallic systems are made.
DEFF Research Database (Denmark)
Lindvang, Charlotte
2013-01-01
The article presents a part of the authors PhD-study in music therapy about self-experiential training and the development of music therapeutic competencies. One of the purposes of the study was to explore and generate understanding and insight into the phenomena of learning through self......, and analysed with the theory of cybernetic psychology. The study as a whole showed how self-experience and practical-oriented training prepare students to go into the complex reality of clinical practice with a well-developed ability to meet clients and their special needs....
Enhanced energy storage in chaotic optical resonators
Liu, Changxu
2013-05-05
Chaos is a phenomenon that occurs in many aspects of contemporary science. In classical dynamics, chaos is defined as a hypersensitivity to initial conditions. The presence of chaos is often unwanted, as it introduces unpredictability, which makes it difficult to predict or explain experimental results. Conversely, we demonstrate here how chaos can be used to enhance the ability of an optical resonator to store energy. We combine analytic theory with ab initio simulations and experiments in photonic-crystal resonators to show that a chaotic resonator can store six times more energy than its classical counterpart of the same volume. We explain the observed increase by considering the equipartition of energy among all degrees of freedom of the chaotic resonator (that is, the cavity modes) and discover a convergence of their lifetimes towards a single value. A compelling illustration of the theory is provided by enhanced absorption in deformed polystyrene microspheres. © 2013 Macmillan Publishers Limited. All rights reserved.
MRI (Magnetic Resonance Imaging)
... Medical Imaging MRI (Magnetic Resonance Imaging) MRI (Magnetic Resonance Imaging) Share Tweet Linkedin Pin it More sharing options Linkedin Pin it Email Print Magnetic Resonance Imaging (MRI) is a medical imaging procedure for ...
Directory of Open Access Journals (Sweden)
Luis Daniel Lledó
2015-03-01
Full Text Available This paper presents an application formed by a classification method based on the architecture of ART neural network (Adaptive Resonance Theory and the Fuzzy Set Theory to classify physiological reactions in order to automatically and dynamically adapt a robot-assisted rehabilitation therapy to the patient needs, using a three-dimensional task in a virtual reality system. Firstly, the mathematical and structural model of the neuro-fuzzy classification method is described together with the signal and training data acquisition. Then, the virtual designed task with physics behavior and its development procedure are explained. Finally, the general architecture of the experimentation for the auto-adaptive therapy is presented using the classification method with the virtual reality exercise.
Electroexcitation of nucleon resonances
Energy Technology Data Exchange (ETDEWEB)
Inna Aznauryan, Volker D. Burkert
2012-01-01
We review recent progress in the investigation of the electroexcitation of nucleon resonances, both in experiment and in theory. The most accurate results have been obtained for the electroexcitation amplitudes of the four lowest excited states, which have been measured in a range of Q2 up to 8 and 4.5 GeV2 for the Delta(1232)P33, N(1535)S11 and N(1440)P11, N(1520)D13, respectively. These results have been confronted with calculations based on lattice QCD, large-Nc relations, perturbative QCD (pQCD), and QCD-inspired models. The amplitudes for the Delta(1232) indicate large pion-cloud contributions at low Q2 and don't show any sign of approaching the pQCD regime for Q2<7 GeV2. Measured for the first time, the electroexcitation amplitudes of the Roper resonance, N(1440)P11, provide strong evidence for this state as a predominantly radial excitation of a three-quark (3q) ground state, with additional non-3-quark contributions needed to describe the low Q2 behavior of the amplitudes. The longitudinal transition amplitude for the N(1535)S11 was determined and has become a challenge for quark models. Explanations may require large meson-cloud contributions or alternative representations of this state. The N(1520)D13 clearly shows the rapid changeover from helicity-3/2 dominance at the real photon point to helicity-1/2 dominance at Q2 > 0.5 GeV2, confirming a long-standing prediction of the constituent quark model. The interpretation of the moments of resonance transition form factors in terms of transition transverse charge distributions in infinite momentum frame is presented.
National Aeronautics and Space Administration — Advanced Diagnostics and Prognostics Testbed (ADAPT) Project Lead: Scott Poll Subject Fault diagnosis in electrical power systems Description The Advanced...
Highly Tunable Electrostatic Nanomechanical Resonators
Kazmi, Syed Naveed Riaz
2017-11-24
There has been significant interest towards highly tunable resonators for on-demand frequency selection in modern communication systems. Here, we report highly tunable electrostatically actuated silicon-based nanomechanical resonators. In-plane doubly-clamped bridges, slightly curved as shallow arches due to residual stresses, are fabricated using standard electron beam lithography and surface nanomachining. The resonators are designed such that the effect of mid-plane stretching dominates the softening effect of the electrostatic force. This is achieved by controlling the gap-to-thickness ratio and by exploiting the initial curvature of the structure from fabrication. We demonstrate considerable increase in the resonance frequency of nanoresonators with the dc bias voltages up to 108% for 180 nm thick structures with a transduction gap of 1
Nonlinear Dynamics of Nanomechanical Resonators
Ramakrishnan, Subramanian; Gulak, Yuiry; Sundaram, Bala; Benaroya, Haym
2007-03-01
Nanoelectromechanical systems (NEMS) offer great promise for many applications including motion and mass sensing. Recent experimental results suggest the importance of nonlinear effects in NEMS, an issue which has not been addressed fully in theory. We report on a nonlinear extension of a recent analytical model by Armour et al [1] for the dynamics of a single-electron transistor (SET) coupled to a nanomechanical resonator. We consider the nonlinear resonator motion in both (a) the Duffing and (b) nonlinear pendulum regimes. The corresponding master equations are derived and solved numerically and we consider moment approximations as well. In the Duffing case with hardening stiffness, we observe that the resonator is damped by the SET at a significantly higher rate. In the cases of softening stiffness and the pendulum, there exist regimes where the SET adds energy to the resonator. To our knowledge, this is the first instance of a single model displaying both negative and positive resonator damping in different dynamical regimes. The implications of the results for SET sensitivity as well as for, as yet unexplained, experimental results will be discussed. 1. Armour et al. Phys.Rev.B (69) 125313 (2004).
Regenerative feedback resonant circuit
Jones, A. Mark; Kelly, James F.; McCloy, John S.; McMakin, Douglas L.
2014-09-02
A regenerative feedback resonant circuit for measuring a transient response in a loop is disclosed. The circuit includes an amplifier for generating a signal in the loop. The circuit further includes a resonator having a resonant cavity and a material located within the cavity. The signal sent into the resonator produces a resonant frequency. A variation of the resonant frequency due to perturbations in electromagnetic properties of the material is measured.
DEFF Research Database (Denmark)
Jørgensen, Frances; Boer, Harry
2006-01-01
In this paper, data from a longitudinal case study in an organization attempting to adapt its internal work processes to changes in its external context are presented, analyzed and discussed. Specifically, functionally structured work teams in one department of a Danish production facility were...... on the proper alignment between the structuring of the work processes and characteristics of the external context (Lawrence & Lorsch, 1967) – it provides a unique opportunity to explore the adaptation process in practice. The paper contributes to the development of contingency theory by lending support...... to the premise that “fit” between an organization’s external context and its internal structure may enhance performance, but also to the suggestion that the adaptation process may be asymmetric (Moon et al., 2004). Further, the paper contributes to practice by highlighting both the opportunities and risks...
Maslennikov, O. V.; Nekorkin, V. I.
2017-10-01
Dynamical networks are systems of active elements (nodes) interacting with each other through links. Examples are power grids, neural structures, coupled chemical oscillators, and communications networks, all of which are characterized by a networked structure and intrinsic dynamics of their interacting components. If the coupling structure of a dynamical network can change over time due to nodal dynamics, then such a system is called an adaptive dynamical network. The term ‘adaptive’ implies that the coupling topology can be rewired; the term ‘dynamical’ implies the presence of internal node and link dynamics. The main results of research on adaptive dynamical networks are reviewed. Key notions and definitions of the theory of complex networks are given, and major collective effects that emerge in adaptive dynamical networks are described.
Design of resonant mirrors with negative group delay.
Gellineau, Antonio; Wong, Yu-Po; Solgaard, Olav
2014-11-17
Resonant mirrors introduce large spectral gradients in reflected phase while maintaining high reflectivity, allowing synthesis of optimized reflected phase for many practical applications. In this paper we show theoretically that asymmetry is required for negative group delay in lossless mirrors and explore the limits of reflected phase in resonant mirrors through the use of coupled mode theory and rigorous couple wave analysis. Our coupled mode theory shows that the phase response of resonant mirrors is determined by interacting resonances and gives insight into tradeoffs in design of mirrors with desired phase response.
Adaptation and Natural Selection revisited.
Sober, E; Wilson, D S
2011-02-01
In Adaptation and Natural Selection, George C. Williams linked the distinction between group and individual adaptation with the distinction between group and individual selection. Williams' Principle, as we will call it, says that adaptation at a level requires selection at that level. This is a necessary but not a sufficient condition; for example, group adaptation requires group selection, but the fact that group selection influences a trait's evolution does not suffice for the resulting trait frequency to be a group adaptation. What more is required? In this paper, we describe an answer to this question that has been developed in multilevel selection theory. We also discuss an alternative framework for defining units of adaptation that violates Williams' Principle. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.
International Development Research Centre (IDRC) Digital Library (Canada)
By Reg'
formed a real foundation for endogenous, and, therefore, sustainable, strategies for adaptation to climate change. The stories reinforce what we already knew: that successful adaptation must come from the people who are living on the front lines, facing the many problems caused by climate change and climate variation.
Motivation--Hygiene Theory Adapted for Education
Timmreck, Thomas C.
1977-01-01
As educators, are we stifling learning by using non-motivating, dissatisfying factors and concepts to try to motivate our students? According to the work of Dr. Frederick Herzberg, many teachers may be doing the wrong thing for the right reason. Considers what motivates students to enjoy their educational surroundings and to learn. (Author/RK)
Application and adaptation of Symphonology Bioethical Theory ...
African Journals Online (AJOL)
p1243322
assertion ... professionals offering spiritual counselling and support in a professional clinical setting. The term therefore covers duly trained .... process of communication and dialogue in which one individual's values and expectations, especially ...
Toward a Theory of Adaptive Training
1992-07-01
altering salience come to mind. On the one hand, building speed by practicing running slowly makes little sense. On the other hand, teachers of skills...Examining the procedures used by Goldiamond (1977) in treating stuttering is, however, instructive. Goldiamond’s subjects used an apparatus...slowly at a rate that matched the auditory delay. (Doing so is incompatible with stuttering .) After Ss mastered prolonged speech with 250 ms delay, the
Adaptation for Regularization Operators in Learning Theory
2006-09-10
fρ over specific prior classes defined in term of finiteness of the constants Cr and Ds. The main assumption is the requirement mv ≥ m/ log m. Since...dimensional, the choice R(λ̇) = r̄ fulfills trivially the required conditions. Second, from definition (25), it is clear that if the sequence {a(λi...59–85, February 2005. [7] E. De Vito, L. Rosasco, and A. Caponnetto. Discretization error analysis for tikhonov regu- larization. to appear in Analisys
Coherence Phenomena in Coupled Optical Resonators
Smith, D. D.; Chang, H.
2004-01-01
We predict a variety of photonic coherence phenomena in passive and active coupled ring resonators. Specifically, the effective dispersive and absorptive steady-state response of coupled resonators is derived, and used to determine the conditions for coupled-resonator-induced transparency and absorption, lasing without gain, and cooperative cavity emission. These effects rely on coherent photon trapping, in direct analogy with coherent population trapping phenomena in atomic systems. We also demonstrate that the coupled-mode equations are formally identical to the two-level atom Schrodinger equation in the rotating-wave approximation, and use this result for the analysis of coupled-resonator photon dynamics. Notably, because these effects are predicted directly from coupled-mode theory, they are not unique to atoms, but rather are fundamental to systems of coherently coupled resonators.
Scalar resonances as two-quark states
International Nuclear Information System (INIS)
Shabalin, E.P.
1984-01-01
On the base of the theory with U(3)xU(3) symmetric chiral Lagrangian the properties of the two-quark scalar mesons are considered. It is shown, that the scalar resonances delta (980) and K(1240) may be treated as the p-wave states of anti qq system. The properties of the isovector and strange scalar mesons, obtained as a propetrties of the two-quark states, turn out to be very close to the properties of the isovector scalar resonance delta (980) and strange resonance K(1240)
International Nuclear Information System (INIS)
Wellens, Thomas; Shatokhin, Vyacheslav; Buchleitner, Andreas
2004-01-01
We are taught by conventional wisdom that the transmission and detection of signals is hindered by noise. However, during the last two decades, the paradigm of stochastic resonance (SR) proved this assertion wrong: indeed, addition of the appropriate amount of noise can boost a signal and hence facilitate its detection in a noisy environment. Due to its simplicity and robustness, SR has been implemented by mother nature on almost every scale, thus attracting interdisciplinary interest from physicists, geologists, engineers, biologists and medical doctors, who nowadays use it as an instrument for their specific purposes. At the present time, there exist a lot of diversified models of SR. Taking into account the progress achieved in both theoretical understanding and practical application of this phenomenon, we put the focus of the present review not on discussing in depth technical details of different models and approaches but rather on presenting a general and clear physical picture of SR on a pedagogical level. Particular emphasis will be given to the implementation of SR in generic quantum systems-an issue that has received limited attention in earlier review papers on the topic. The major part of our presentation relies on the two-state model of SR (or on simple variants thereof), which is general enough to exhibit the main features of SR and, in fact, covers many (if not most) of the examples of SR published so far. In order to highlight the diversity of the two-state model, we shall discuss several examples from such different fields as condensed matter, nonlinear and quantum optics and biophysics. Finally, we also discuss some situations that go beyond the generic SR scenario but are still characterized by a constructive role of noise
Wellens, Thomas; Shatokhin, Vyacheslav; Buchleitner, Andreas
2004-01-01
We are taught by conventional wisdom that the transmission and detection of signals is hindered by noise. However, during the last two decades, the paradigm of stochastic resonance (SR) proved this assertion wrong: indeed, addition of the appropriate amount of noise can boost a signal and hence facilitate its detection in a noisy environment. Due to its simplicity and robustness, SR has been implemented by mother nature on almost every scale, thus attracting interdisciplinary interest from physicists, geologists, engineers, biologists and medical doctors, who nowadays use it as an instrument for their specific purposes. At the present time, there exist a lot of diversified models of SR. Taking into account the progress achieved in both theoretical understanding and practical application of this phenomenon, we put the focus of the present review not on discussing in depth technical details of different models and approaches but rather on presenting a general and clear physical picture of SR on a pedagogical level. Particular emphasis will be given to the implementation of SR in generic quantum systems—an issue that has received limited attention in earlier review papers on the topic. The major part of our presentation relies on the two-state model of SR (or on simple variants thereof), which is general enough to exhibit the main features of SR and, in fact, covers many (if not most) of the examples of SR published so far. In order to highlight the diversity of the two-state model, we shall discuss several examples from such different fields as condensed matter, nonlinear and quantum optics and biophysics. Finally, we also discuss some situations that go beyond the generic SR scenario but are still characterized by a constructive role of noise.
Parametric resonances: from the Mathieu equation to QASER
Chen, Goong; Tian, Jing; Bin-Mohsin, Bandar; Nessler, Reed; Svidzinsky, Anatoly; Scully, Marlan O.
2016-07-01
Combination resonances produced by periodic modulation of parameters can generate substantial gains in new light amplifiers, acronymed QASER (quantum amplification by superradiant emission of radiation). Here we study such gains and investigate their parametric resonance spectral patterns. We use the Floquet theory and develop a projection method that can properly capture gains near the primary resonance and subharmonic frequencies for the Mathieu equation and QASER. We dedicate this paper to the memory of Richard Lewis Arnowitt a pioneer of many-body theory, a pathfinder at the interface of gravity and quantum mechanics, and a true leader in quantum field theory.
Introduction to Fuzzy Set Theory
Kosko, Bart
1990-01-01
An introduction to fuzzy set theory is described. Topics covered include: neural networks and fuzzy systems; the dynamical systems approach to machine intelligence; intelligent behavior as adaptive model-free estimation; fuzziness versus probability; fuzzy sets; the entropy-subsethood theorem; adaptive fuzzy systems for backing up a truck-and-trailer; product-space clustering with differential competitive learning; and adaptive fuzzy system for target tracking.
Brand Identity, Adaptation, and Media Franchise Culture
Directory of Open Access Journals (Sweden)
Marazi Katerina
2014-12-01
Full Text Available In spite of the noticeable practices within the field of Adaptation, Adaptation theory seems to be lagging behind whilst perpetuating various fallacies. Geoffrey Wagner’s types of Adaptation and Kamilla Elliott’s proposed concepts for examining adaptations have proved useful but due to their general applicability they seem to perpetuate the fallacies existing within the field of Adaptation. This article will propose a context-specific concept pertaining to Media Franchise Culture for the purpose of examining Adaptations and re-assessing long-held debates concerning the Original, the Content/Form debate and Fidelity issues that cater to the twelve fallacies discussed by Thomas Leitch.
Complex Systems: An Introduction-Information Theory, Chaos ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 8. Complex Systems: An Introduction - Information Theory, Chaos Theory and Computational Complexity. V K Wadhawan. General Article Volume 14 Issue 8 August 2009 pp 761-781 ...
Measurement of optical Feshbach resonances in an ideal gas.
Blatt, S; Nicholson, T L; Bloom, B J; Williams, J R; Thomsen, J W; Julienne, P S; Ye, J
2011-08-12
Using a narrow intercombination line in alkaline earth atoms to mitigate large inelastic losses, we explore the optical Feshbach resonance effect in an ultracold gas of bosonic (88)Sr. A systematic measurement of three resonances allows precise determinations of the optical Feshbach resonance strength and scaling law, in agreement with coupled-channel theory. Resonant enhancement of the complex scattering length leads to thermalization mediated by elastic and inelastic collisions in an otherwise ideal gas. Optical Feshbach resonance could be used to control atomic interactions with high spatial and temporal resolution.
Resonance – Journal of Science Education | Indian Academy of ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education. Dipankar Nandi. Articles written in Resonance – Journal of Science Education. Volume 14 Issue 5 May 2009 pp 455-471 General Article. The Major Players in Adaptive Immunity - Humoral Immunity · Asma Ahmed Banishree Saha Anand Patwardhan Shwetha ...
Resonance – Journal of Science Education | Indian Academy of ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education. V Sheeba. Articles written in Resonance – Journal of Science Education. Volume 4 Issue 1 January 1999 pp 73-75 Research News. Adaptive Significance of Circadian Rhythms - Biological Clocks and Darwinian Fitness in Cyanobacteria · V Sheeba Vijay Kumar ...
Resonance – Journal of Science Education | Indian Academy of ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education. Vijay Kumar Sharma. Articles written in Resonance – Journal of Science Education. Volume 4 Issue 1 January 1999 pp 73-75 Research News. Adaptive Significance of Circadian Rhythms - Biological Clocks and Darwinian Fitness in Cyanobacteria · V Sheeba ...
Resonance – Journal of Science Education | Indian Academy of ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education. Asma Ahmed. Articles written in Resonance – Journal of Science Education. Volume 14 Issue 5 May 2009 pp 455-471 General Article. The Major Players in Adaptive Immunity - Humoral Immunity · Asma Ahmed Banishree Saha Anand Patwardhan Shwetha ...
Resonance – Journal of Science Education | Indian Academy of ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education. Shwetha Shivprasad. Articles written in Resonance – Journal of Science Education. Volume 14 Issue 5 May 2009 pp 455-471 General Article. The Major Players in Adaptive Immunity - Humoral Immunity · Asma Ahmed Banishree Saha Anand Patwardhan ...
Resonance – Journal of Science Education | Indian Academy of ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education. Shwetha Shivaprasad. Articles written in Resonance – Journal of Science Education. Volume 14 Issue 6 June 2009 pp 610-621 General Article. The Major Players in Adaptive Immunity - Cell-mediated Immunity · Asma Ahmed Banishree Saha Anand Patwardhan ...
Hermann Weyl and Representation Theory
Indian Academy of Sciences (India)
His work on the theory ofLie groups was motivated by his life-long interest in quantummechanics and relativity. When Weyl entered Lie theory,it mostly focussed on the infinitesimal, and he strove to bringin a global perspective. Time and again, Weyl's ideas arisingin one context have been adapted and applied to wholly ...
DEFF Research Database (Denmark)
di Vecchia, Paolo; Cappelli, Andrea; Colomo, Filippo
of gravity unified with the other forces, and its successive developments up to the superstring revolution in 1984. Providing important background information to current debates on the theory, this book is essential reading for students and researchers in physics, as well as historians and philosophers......tring theory is currently the best candidate for a unified theory of all forces and all forms of matter in nature. As such, it has become a focal point for physical and philosophical discussions. This unique book explores the history of the theory's early stages of development, as told by its main...... protagonists. The book journeys from the first version of the theory (the so-called dual resonance model) in the late sixties, as an attempt to describe the physics of strong interactions outside the framework of quantum field theory, to its reinterpretation around the mid-seventies as a quantum theory...
Castellani, Elena; Colomo, Filippo; Di Vecchia, Paolo
2012-01-01
String theory is currently the best candidate for a unified theory of all forces and all forms of matter in nature. As such, it has become a focal point for physical and philosophical discussions. This unique book explores the history of the theory's early stages of development, as told by its main protagonists. The book journeys from the first version of the theory (the so-called dual resonance model) in the late sixties, as an attempt to describe the physics of strong interactions outside the framework of quantum field theory, to its reinterpretation around the mid-seventies as a quantum theory of gravity unified with the other forces, and its successive developments up to the superstring revolution in 1984. Providing important background information to current debates on the theory, this book is essential reading for students and researchers in physics, as well as historians and philosophers of science.
DEFF Research Database (Denmark)
di Vecchia, Paolo; Cappelli, Andrea; Colomo, Filippo
tring theory is currently the best candidate for a unified theory of all forces and all forms of matter in nature. As such, it has become a focal point for physical and philosophical discussions. This unique book explores the history of the theory's early stages of development, as told by its main...... protagonists. The book journeys from the first version of the theory (the so-called dual resonance model) in the late sixties, as an attempt to describe the physics of strong interactions outside the framework of quantum field theory, to its reinterpretation around the mid-seventies as a quantum theory...... of gravity unified with the other forces, and its successive developments up to the superstring revolution in 1984. Providing important background information to current debates on the theory, this book is essential reading for students and researchers in physics, as well as historians and philosophers...
Desseilles, Martin
In this article, we address adaptation in relation to the neurosciences. Adaptation is examined at the individual as well as various environmental levels: biological, psychological, and social. We then briefly discuss, from a neuroscientific perspective, the concept of adaptation in relation to psychopathology, including attachment theory and the third wave of cognitive-behavioral therapies.
Exceptional Parent, 1987
1987-01-01
Suggestions are presented for helping disabled individuals learn to use or adapt toothbrushes for proper dental care. A directory lists dental health instructional materials available from various organizations. (CB)
DEFF Research Database (Denmark)
Møller Larsen, Marcus; Lyngsie, Jacob
2017-01-01
intense relational mechanisms provide an effective means for contingency adaptation and therefore reduce the probability of premature termination. However, in situations where relationships are already governed by longer duration contracts, we argue that investments in relational mechanism create...
Molecular quantum dynamics from theory to applications
Gatti, Fabien
2014-01-01
Emphasizing fundamental educational concepts, this book offers an accessible introduction that covers eigenstates, wave packets, quantum mechanical resonances and more. Examples show that high-level experiments and theory must work closely together.
DEFF Research Database (Denmark)
Møller Larsen, Marcus; Lyngsie, Jacob
We investigate why some exchange relationships terminate prematurely. We argue that investments in informal governance structures induce premature termination in relationships already governed by formal contracts. The formalized adaptive behavior of formal governance structures and the flexible...... and reciprocal adaptation of informal governance structure create ambiguity in situations of contingencies, which, subsequently, increases the likelihood of premature relationship termination. Using a large sample of exchange relationships in the global service provider industry, we find support for a hypothesis...
DEFF Research Database (Denmark)
Andersen, Torben Juul
2015-01-01
This article provides an overview of theoretical contributions that have influenced the discourse around strategic adaptation including contingency perspectives, strategic fit reasoning, decision structure, information processing, corporate entrepreneurship, and strategy process. The related...... concepts of strategic renewal, dynamic managerial capabilities, dynamic capabilities, and strategic response capabilities are discussed and contextualized against strategic responsiveness. The insights derived from this article are used to outline the contours of a dynamic process of strategic adaptation...
DEFF Research Database (Denmark)
Berth, Mette
2005-01-01
This paper focuses on the use of an adaptive ethnography when studying such phenomena as young people's use of mobile media in a learning perspective. Mobile media such as PDAs and mobile phones have a number of affordances which make them potential tools for learning. However, before we begin...... formal and informal learning contexts. The paper also proposes several adaptive methodological techniques for studying young people's interaction with mobiles....
Laser Resonators and Beam Propagation Fundamentals, Advanced Concepts and Applications
Hodgson, Norman
2005-01-01
Optical Resonators provides a detailed discussion of the properties of optical resonators for lasers from basic theory to recent research. In addition to describing the fundamental theories of resonators such as geometrical optics, diffraction, and polarisation the characteristics of all important resonator schemes and their calculation are presented. Experimental examples, practical problems and a collection of measurement techniques support the comprehensive treatment of the subject. Optical Resonators is the only book currently available that provides a comprehensive overview of the the subject. Combined with the structure of the text and the autonomous nature of the chapters this work will be as suitable for those new to the field as it will be invaluable to specialists conducting research. This second edition has been enlarged by new sections on Q-switching and resonators with internal phase/amplitude control. In addition, the whole book has been brought up-to-date.
The resonance energy of benzene: a revisit.
Mo, Yirong
2009-04-30
Zielinski and van Lenthe recently extended the block-localized wave function (BLW) method by introducing the resonating BLW (RBLW) method and performed test calculations on hexagonal H(6) and benzene [J. Phys. Chem. A 2008, 112, 13197]. However, the Pauling's resonance energies from their RBLW and ab initio valence bond (VB) calculations were greatly underestimated largely due to the imperfect use of either one-electron orbitals (method = delocal) or resonance structures (method = local). Whereas it has been well recognized that electronic resonance within a molecular system plays a stabilizing role, there are many indirect experimental evidences available to evaluate the resonance energy and, thus, to justify computational results. Here we used the BLW method, which can be regarded as the simplest variant of modern ab initio VB theory, to re-evaluate the resonance energy of benzene at the B3LYP level, following the original definition by Pauling and Wheland, who obtained the resonance energy "by subtracting the actual energy of the molecule in question from that of the most stable contributing structure". The computed vertical resonance energy (or quantum mechanical resonance energy) in benzene is 88.8, 92.2, or 87.9 kcal/mol with the basis sets of 6-31G(d), 6-311+G(d,p), or cc-pVTZ, respectively, while the adiabatic resonance energy (or theoretical resonance energy) is 61.4, 63.2, or 62.4 kcal/mol, exhibiting insignificant basis set dependency for moderate basis sets. In line with predictions, the geometry optimization of the elusive cyclohexatriene (i.e., the Kekule structure) with the BLW method also resulted in carbon-carbon bond lengths (e.g., 1.322 and 1.523 A with the cc-pVTZ basis set) comparable to those in ethylene or ethane.
Resonance and Neck Length for a Spherical Resonator
Directory of Open Access Journals (Sweden)
Emily Corning
2011-06-01
Full Text Available The relationship between the neck length of a spherical resonator and its period of fundamental resonance was investigated. This was done by measuring the frequency of fundamental resonance of the resonator at 6 different neck lengths. It was found that its resonance resembled Helmholtz resonance but was not that of ideal Helmholtz resonance.
Pulse sequences for contrast-enhanced magnetic resonance imaging
International Nuclear Information System (INIS)
Graves, Martin J.
2007-01-01
The theory and application of magnetic resonance imaging (MRI) pulse sequences following the administration of an exogenous contrast agent are discussed. Pulse sequences are categorised according to the contrast agent mechanism: changes in proton density, relaxivity, magnetic susceptibility and resonant frequency shift. Applications in morphological imaging, magnetic resonance angiography, dynamic imaging and cell labelling are described. The importance of optimising the pulse sequence for each application is emphasised
Energy Technology Data Exchange (ETDEWEB)
Konrad, F.; Nennig, E.; Kress, B.; Sartor, K.; Stippich, C. [Abteilung Neuroradiologie, Neurologische Klinik, Universitaetsklinikum Heidelberg (Germany); Ochmann, H. [Neurochirurgische Klinik, Universitaetsklinikum Heidelberg (Germany)
2005-03-01
Purpose: Functional magnetic resonance imaging (fMRI) localizes Broca's area (B) and Wernicke's area (W) and the hemisphere dominant for language. In clinical fMRI, adapting the stimulation paradigms to each patient's individual cognitive capacity is crucial for diagnostic success. To interpret clinical fMRI findings correctly, we studied the effect of varying frequency and number of stimuli on functional localization, determination of language dominance and BOLD signals. Materials and Methods: Ten volunteers (VP) were investigated at 1.5 Tesla during visually triggered sentence generation using a standardized block design. In four different measurements, the stimuli were presented to each VP with frequencies of (1/1)s, (1/2)s,(1/3)s and (1/6)s. Results: The functional localizations and the correlations of the measured BOLD signals to the applied hemodynamic reference function (r) were almost independent from frequency and number of the stimuli in both hemispheres, whereas the relative BOLD signal changes ({delta}S) in B and W increased with the stimulation rate, which also changed the lateralization indices. The strongest BOLD activations were achieved with the highest stimulation rate or with the maximum language production task, respectively. Conclusion: The adaptation of language paradigms necessary in clinical fMRI does not alter the functional localizations but changes the BOLD signals and language lateralization which should not be attributed to the underlying brain pathology. (orig.)
On the Resonant Frequencies of the Oja | Nwachukwu | Nigerian ...
African Journals Online (AJOL)
A method for calculating the unblown resonant frequencies of an 'Oja' (a traditional Nigerian musical instrument) is developed. Support for the theory is provided by data derived from experimentally measured spectra of typical oja tones. It is also shown that for resonant frequencies below about 2000Hz, the differences ...
Resonance – Journal of Science Education | Indian Academy of ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education. G Kallianpur. Articles written in Resonance – Journal of Science Education. Volume 4 Issue 1 January 1999 pp 32-35 General Article. Norbert Wiener and Probability Theory - Some Reflections · G Kallianpur · More Details Fulltext PDF ...
Resonance – Journal of Science Education | Indian Academy of ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education. Sriranjan Banerji. Articles written in Resonance – Journal of Science Education. Volume 11 Issue 2 February 2006 pp 27-42 General Article. How Einstein Discovered the Special Theory of Relativity · Sriranjan Banerji · More Details Fulltext PDF ...
Resonance – Journal of Science Education | Indian Academy of ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education. P G Babu. Articles written in Resonance – Journal of Science Education. Volume 3 Issue 7 July 1998 pp 53-60 General Article. Game Theory - Nash Equilibrium · P G Babu · More Details Fulltext PDF. Volume 3 Issue 8 August 1998 pp 46-55 General Article.
Resonance – Journal of Science Education | Indian Academy of ...
Indian Academy of Sciences (India)
Home; Journals; Resonance – Journal of Science Education. Rajkumar Radder. Articles written in Resonance – Journal of Science Education. Volume 11 Issue 4 April 2006 pp 100-105 Classroom. On Teaching the Theory of Evolution · Rajkumar Radder · More Details Fulltext PDF ...
Search for new resonances with boosted signatures at CMS
CERN. Geneva
2015-01-01
The LHC and its experiments are ideally suited to search for these new resonances in order to validate or constrain the corresponding theories. At resonance masses well above 1 TeV, these searches face specific challenges. The decay products have large Lorentz boosts, resulting in very collimated final state topologies. Jet substructure methods and the use of non-isolate...