A study of quantum mechanical probabilities in the classical Hodgkin-Huxley model.

Science.gov (United States)

Moradi, N; Scholkmann, F; Salari, V

2015-03-01

The Hodgkin-Huxley (HH) model is a powerful model to explain different aspects of spike generation in excitable cells. However, the HH model was proposed in 1952 when the real structure of the ion channel was unknown. It is now common knowledge that in many ion-channel proteins the flow of ions through the pore is governed by a gate, comprising a so-called "selectivity filter" inside the ion channel, which can be controlled by electrical interactions. The selectivity filter (SF) is believed to be responsible for the selection and fast conduction of particular ions across the membrane of an excitable cell. Other (generally larger) parts of the molecule such as the pore-domain gate control the access of ions to the channel protein. In fact, two types of gates are considered here for ion channels: the "external gate", which is the voltage sensitive gate, and the "internal gate" which is the selectivity filter gate (SFG). Some quantum effects are expected in the SFG due to its small dimensions, which may play an important role in the operation of an ion channel. Here, we examine parameters in a generalized model of HH to see whether any parameter affects the spike generation. Our results indicate that the previously suggested semi-quantum-classical equation proposed by Bernroider and Summhammer (BS) agrees strongly with the HH equation under different conditions and may even provide a better explanation in some cases. We conclude that the BS model can refine the classical HH model substantially.

[Hardware Implementation of Numerical Simulation Function of Hodgkin-Huxley Model Neurons Action Potential Based on Field Programmable Gate Array].

Science.gov (United States)

Wang, Jinlong; Lu, Mai; Hu, Yanwen; Chen, Xiaoqiang; Pan, Qiangqiang

2015-12-01

Neuron is the basic unit of the biological neural system. The Hodgkin-Huxley (HH) model is one of the most realistic neuron models on the electrophysiological characteristic description of neuron. Hardware implementation of neuron could provide new research ideas to clinical treatment of spinal cord injury, bionics and artificial intelligence. Based on the HH model neuron and the DSP Builder technology, in the present study, a single HH model neuron hardware implementation was completed in Field Programmable Gate Array (FPGA). The neuron implemented in FPGA was stimulated by different types of current, the action potential response characteristics were analyzed, and the correlation coefficient between numerical simulation result and hardware implementation result were calculated. The results showed that neuronal action potential response of FPGA was highly consistent with numerical simulation result. This work lays the foundation for hardware implementation of neural network.

Dynamical mean-field theory of noisy spiking neuron ensembles: Application to the Hodgkin-Huxley model

International Nuclear Information System (INIS)

Hasegawa, Hideo

2003-01-01

A dynamical mean-field approximation (DMA) previously proposed by the present author [H. Hasegawa, Phys. Rev E 67, 041903 (2003)] has been extended to ensembles described by a general noisy spiking neuron model. Ensembles of N-unit neurons, each of which is expressed by coupled K-dimensional differential equations (DEs), are assumed to be subject to spatially correlated white noises. The original KN-dimensional stochastic DEs have been replaced by K(K+2)-dimensional deterministic DEs expressed in terms of means and the second-order moments of local and global variables: the fourth-order contributions are taken into account by the Gaussian decoupling approximation. Our DMA has been applied to an ensemble of Hodgkin-Huxley (HH) neurons (K=4), for which effects of the noise, the coupling strength, and the ensemble size on the response to a single-spike input have been investigated. Numerical results calculated by the DMA theory are in good agreement with those obtained by direct simulations, although the former computation is about a thousand times faster than the latter for a typical HH neuron ensemble with N=100

Optimal decoding and information transmission in Hodgkin-Huxley neurons under metabolic cost constraints.

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Kostal, Lubomir; Kobayashi, Ryota

2015-10-01

Information theory quantifies the ultimate limits on reliable information transfer by means of the channel capacity. However, the channel capacity is known to be an asymptotic quantity, assuming unlimited metabolic cost and computational power. We investigate a single-compartment Hodgkin-Huxley type neuronal model under the spike-rate coding scheme and address how the metabolic cost and the decoding complexity affects the optimal information transmission. We find that the sub-threshold stimulation regime, although attaining the smallest capacity, allows for the most efficient balance between the information transmission and the metabolic cost. Furthermore, we determine post-synaptic firing rate histograms that are optimal from the information-theoretic point of view, which enables the comparison of our results with experimental data. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Synchronization of a coupled Hodgkin-Huxley neurons via high order sliding-mode feedback

Energy Technology Data Exchange (ETDEWEB)

Aguilar-Lopez, R. [Division de Ciencias Basicas e Ingenieria, Universidad Autonoma Metropolitana, Av. San Pablo No. 180, Reynosa-Tamaulipas, 02200 Azcapotzalco, Mexico, D.F. (Mexico)], E-mail: raguilar@correo.azc.uam.mx; Martinez-Guerra, R. [Departamento de Control Automatico, CINVESTAV-IPN, Apartado Postal 14-740, Mexico, D.F. C.P. 07360 (Mexico)], E-mail: rguerra@ctrl.cinvestav.mx

2008-07-15

This work deals with the synchronizations of two both coupled Hodgkin-Huxley (H-H) neurons, where the master neuron posses inner noise and the slave neuron is considered in a resting state, (without inner noise) and an exciting state (with inner noise). The synchronization procedure is done via a feedback control, considering a class of high order sliding-mode controller which provides chattering reduction and finite time synchronization convergence, with a satisfactory performance. Theoretical analysis is done in order to show the closed-loop stability of the proposed controller and the calculated finite time for convergence. The main results are illustrated via numerical experiments.

Synchronization of a coupled Hodgkin-Huxley neurons via high order sliding-mode feedback

International Nuclear Information System (INIS)

Aguilar-Lopez, R.; Martinez-Guerra, R.

2008-01-01

This work deals with the synchronizations of two both coupled Hodgkin-Huxley (H-H) neurons, where the master neuron posses inner noise and the slave neuron is considered in a resting state, (without inner noise) and an exciting state (with inner noise). The synchronization procedure is done via a feedback control, considering a class of high order sliding-mode controller which provides chattering reduction and finite time synchronization convergence, with a satisfactory performance. Theoretical analysis is done in order to show the closed-loop stability of the proposed controller and the calculated finite time for convergence. The main results are illustrated via numerical experiments

Spike neural models (part I: The Hodgkin-Huxley model

Directory of Open Access Journals (Sweden)

Johnson, Melissa G.

2017-05-01

Full Text Available Artificial neural networks, or ANNs, have grown a lot since their inception back in the 1940s. But no matter the changes, one of the most important components of neural networks is still the node, which represents the neuron. Within spiking neural networks, the node is especially important because it contains the functions and properties of neurons that are necessary for their network. One important aspect of neurons is the ionic flow which produces action potentials, or spikes. Forces of diffusion and electrostatic pressure work together with the physical properties of the cell to move ions around changing the cell membrane potential which ultimately produces the action potential. This tutorial reviews the Hodkgin-Huxley model and shows how it simulates the ionic flow of the giant squid axon via four differential equations. The model is implemented in Matlab using Euler's Method to approximate the differential equations. By using Euler's method, an extra parameter is created, the time step. This new parameter needs to be carefully considered or the results of the node may be impaired.

Numerical simulations of piecewise deterministic Markov processes with an application to the stochastic Hodgkin-Huxley model

Science.gov (United States)

Ding, Shaojie; Qian, Min; Qian, Hong; Zhang, Xuejuan

2016-12-01

The stochastic Hodgkin-Huxley model is one of the best-known examples of piecewise deterministic Markov processes (PDMPs), in which the electrical potential across a cell membrane, V(t), is coupled with a mesoscopic Markov jump process representing the stochastic opening and closing of ion channels embedded in the membrane. The rates of the channel kinetics, in turn, are voltage-dependent. Due to this interdependence, an accurate and efficient sampling of the time evolution of the hybrid stochastic systems has been challenging. The current exact simulation methods require solving a voltage-dependent hitting time problem for multiple path-dependent intensity functions with random thresholds. This paper proposes a simulation algorithm that approximates an alternative representation of the exact solution by fitting the log-survival function of the inter-jump dwell time, H(t), with a piecewise linear one. The latter uses interpolation points that are chosen according to the time evolution of the H(t), as the numerical solution to the coupled ordinary differential equations of V(t) and H(t). This computational method can be applied to all PDMPs. Pathwise convergence of the approximated sample trajectories to the exact solution is proven, and error estimates are provided. Comparison with a previous algorithm that is based on piecewise constant approximation is also presented.

Teaching and learning the Hodgkin-Huxley model based on software developed in NEURON's programming language hoc.

Science.gov (United States)

Hernández, Oscar E; Zurek, Eduardo E

2013-05-15

We present a software tool called SENB, which allows the geometric and biophysical neuronal properties in a simple computational model of a Hodgkin-Huxley (HH) axon to be changed. The aim of this work is to develop a didactic and easy-to-use computational tool in the NEURON simulation environment, which allows graphical visualization of both the passive and active conduction parameters and the geometric characteristics of a cylindrical axon with HH properties. The SENB software offers several advantages for teaching and learning electrophysiology. First, SENB offers ease and flexibility in determining the number of stimuli. Second, SENB allows immediate and simultaneous visualization, in the same window and time frame, of the evolution of the electrophysiological variables. Third, SENB calculates parameters such as time and space constants, stimuli frequency, cellular area and volume, sodium and potassium equilibrium potentials, and propagation velocity of the action potentials. Furthermore, it allows the user to see all this information immediately in the main window. Finally, with just one click SENB can save an image of the main window as evidence. The SENB software is didactic and versatile, and can be used to improve and facilitate the teaching and learning of the underlying mechanisms in the electrical activity of an axon using the biophysical properties of the squid giant axon.

Delay-enhanced coherence of spiral waves in noisy Hodgkin-Huxley neuronal networks

International Nuclear Information System (INIS)

Wang Qingyun; Perc, Matjaz; Duan Zhisheng; Chen Guanrong

2008-01-01

We study the spatial dynamics of spiral waves in noisy Hodgkin-Huxley neuronal ensembles evoked by different information transmission delays and network topologies. In classical settings of coherence resonance the intensity of noise is fine-tuned so as to optimize the system's response. Here, we keep the noise intensity constant, and instead, vary the length of information transmission delay amongst coupled neurons. We show that there exists an intermediate transmission delay by which the spiral waves are optimally ordered, hence indicating the existence of delay-enhanced coherence of spatial dynamics in the examined system. Additionally, we examine the robustness of this phenomenon as the diffusive interaction topology changes towards the small-world type, and discover that shortcut links amongst distant neurons hinder the emergence of coherent spiral waves irrespective of transmission delay length. Presented results thus provide insights that could facilitate the understanding of information transmission delay on realistic neuronal networks

Control of bursting synchronization in networks of Hodgkin-Huxley-type neurons with chemical synapses.

Science.gov (United States)

Batista, C A S; Viana, R L; Ferrari, F A S; Lopes, S R; Batista, A M; Coninck, J C P

2013-04-01

Thermally sensitive neurons present bursting activity for certain temperature ranges, characterized by fast repetitive spiking of action potential followed by a short quiescent period. Synchronization of bursting activity is possible in networks of coupled neurons, and it is sometimes an undesirable feature. Control procedures can suppress totally or partially this collective behavior, with potential applications in deep-brain stimulation techniques. We investigate the control of bursting synchronization in small-world networks of Hodgkin-Huxley-type thermally sensitive neurons with chemical synapses through two different strategies. One is the application of an external time-periodic electrical signal and another consists of a time-delayed feedback signal. We consider the effectiveness of both strategies in terms of protocols of applications suitable to be applied by pacemakers.

Dynamics from seconds to hours in Hodgkin-Huxley model with time-dependent ion concentrations and buffer reservoirs.

Directory of Open Access Journals (Sweden)

Niklas Hübel

2014-12-01

Full Text Available The classical Hodgkin-Huxley (HH model neglects the time-dependence of ion concentrations in spiking dynamics. The dynamics is therefore limited to a time scale of milliseconds, which is determined by the membrane capacitance multiplied by the resistance of the ion channels, and by the gating time constants. We study slow dynamics in an extended HH framework that includes time-dependent ion concentrations, pumps, and buffers. Fluxes across the neuronal membrane change intra- and extracellular ion concentrations, whereby the latter can also change through contact to reservoirs in the surroundings. Ion gain and loss of the system is identified as a bifurcation parameter whose essential importance was not realized in earlier studies. Our systematic study of the bifurcation structure and thus the phase space structure helps to understand activation and inhibition of a new excitability in ion homeostasis which emerges in such extended models. Also modulatory mechanisms that regulate the spiking rate can be explained by bifurcations. The dynamics on three distinct slow times scales is determined by the cell volume-to-surface-area ratio and the membrane permeability (seconds, the buffer time constants (tens of seconds, and the slower backward buffering (minutes to hours. The modulatory dynamics and the newly emerging excitable dynamics corresponds to pathological conditions observed in epileptiform burst activity, and spreading depression in migraine aura and stroke, respectively.

Dynamics from seconds to hours in Hodgkin-Huxley model with time-dependent ion concentrations and buffer reservoirs.

Science.gov (United States)

Hübel, Niklas; Dahlem, Markus A

2014-12-01

The classical Hodgkin-Huxley (HH) model neglects the time-dependence of ion concentrations in spiking dynamics. The dynamics is therefore limited to a time scale of milliseconds, which is determined by the membrane capacitance multiplied by the resistance of the ion channels, and by the gating time constants. We study slow dynamics in an extended HH framework that includes time-dependent ion concentrations, pumps, and buffers. Fluxes across the neuronal membrane change intra- and extracellular ion concentrations, whereby the latter can also change through contact to reservoirs in the surroundings. Ion gain and loss of the system is identified as a bifurcation parameter whose essential importance was not realized in earlier studies. Our systematic study of the bifurcation structure and thus the phase space structure helps to understand activation and inhibition of a new excitability in ion homeostasis which emerges in such extended models. Also modulatory mechanisms that regulate the spiking rate can be explained by bifurcations. The dynamics on three distinct slow times scales is determined by the cell volume-to-surface-area ratio and the membrane permeability (seconds), the buffer time constants (tens of seconds), and the slower backward buffering (minutes to hours). The modulatory dynamics and the newly emerging excitable dynamics corresponds to pathological conditions observed in epileptiform burst activity, and spreading depression in migraine aura and stroke, respectively.

Spiral Wave in Small-World Networks of Hodgkin-Huxley Neurons

International Nuclear Information System (INIS)

Ma Jun; Zhang Cairong; Yang Lijian; Wu Ying

2010-01-01

The effect of small-world connection and noise on the formation and transition of spiral wave in the networks of Hodgkin-Huxley neurons are investigated in detail. Some interesting results are found in our numerical studies. i) The quiescent neurons are activated to propagate electric signal to others by generating and developing spiral wave from spiral seed in small area. ii) A statistical factor is defined to describe the collective properties and phase transition induced by the topology of networks and noise. iii) Stable rotating spiral wave can be generated and keeps robust when the rewiring probability is below certain threshold, otherwise, spiral wave can not be developed from the spiral seed and spiral wave breakup occurs for a stable rotating spiral wave. iv) Gaussian white noise is introduced on the membrane of neurons to study the noise-induced phase transition on spiral wave in small-world networks of neurons. It is confirmed that Gaussian white noise plays active role in supporting and developing spiral wave in the networks of neurons, and appearance of smaller factor of synchronization indicates high possibility to induce spiral wave. (interdisciplinary physics and related areas of science and technology)

A self-organizing state-space-model approach for parameter estimation in hodgkin-huxley-type models of single neurons.

Directory of Open Access Journals (Sweden)

Dimitrios V Vavoulis

Full Text Available Traditional approaches to the problem of parameter estimation in biophysical models of neurons and neural networks usually adopt a global search algorithm (for example, an evolutionary algorithm, often in combination with a local search method (such as gradient descent in order to minimize the value of a cost function, which measures the discrepancy between various features of the available experimental data and model output. In this study, we approach the problem of parameter estimation in conductance-based models of single neurons from a different perspective. By adopting a hidden-dynamical-systems formalism, we expressed parameter estimation as an inference problem in these systems, which can then be tackled using a range of well-established statistical inference methods. The particular method we used was Kitagawa's self-organizing state-space model, which was applied on a number of Hodgkin-Huxley-type models using simulated or actual electrophysiological data. We showed that the algorithm can be used to estimate a large number of parameters, including maximal conductances, reversal potentials, kinetics of ionic currents, measurement and intrinsic noise, based on low-dimensional experimental data and sufficiently informative priors in the form of pre-defined constraints imposed on model parameters. The algorithm remained operational even when very noisy experimental data were used. Importantly, by combining the self-organizing state-space model with an adaptive sampling algorithm akin to the Covariance Matrix Adaptation Evolution Strategy, we achieved a significant reduction in the variance of parameter estimates. The algorithm did not require the explicit formulation of a cost function and it was straightforward to apply on compartmental models and multiple data sets. Overall, the proposed methodology is particularly suitable for resolving high-dimensional inference problems based on noisy electrophysiological data and, therefore, a

Teaching and learning the Hodgkin-Huxley model based on software developed in NEURON’s programming language hoc

Science.gov (United States)

2013-01-01

Background We present a software tool called SENB, which allows the geometric and biophysical neuronal properties in a simple computational model of a Hodgkin-Huxley (HH) axon to be changed. The aim of this work is to develop a didactic and easy-to-use computational tool in the NEURON simulation environment, which allows graphical visualization of both the passive and active conduction parameters and the geometric characteristics of a cylindrical axon with HH properties. Results The SENB software offers several advantages for teaching and learning electrophysiology. First, SENB offers ease and flexibility in determining the number of stimuli. Second, SENB allows immediate and simultaneous visualization, in the same window and time frame, of the evolution of the electrophysiological variables. Third, SENB calculates parameters such as time and space constants, stimuli frequency, cellular area and volume, sodium and potassium equilibrium potentials, and propagation velocity of the action potentials. Furthermore, it allows the user to see all this information immediately in the main window. Finally, with just one click SENB can save an image of the main window as evidence. Conclusions The SENB software is didactic and versatile, and can be used to improve and facilitate the teaching and learning of the underlying mechanisms in the electrical activity of an axon using the biophysical properties of the squid giant axon. PMID:23675833

Phase-locking and chaos in a silent Hodgkin-Huxley neuron exposed to sinusoidal electric field

International Nuclear Information System (INIS)

Che Yanqiu; Wang Jiang; Si Wenjie; Fei Xiangyang

2009-01-01

Neuronal firing patterns are related to the information processing in neural system. This paper investigates the response characteristics of a silent Hodgkin-Huxley neuron to the stimulation of externally-applied sinusoidal electric field. The neuron exhibits both p:q phase-locked (i.e. a periodic oscillation defined as p action potentials generated by q cycle stimulations) and chaotic behaviors, depending on the values of stimulus frequencies and amplitudes. In one-parameter space, a rich bifurcation structure including period-adding without chaos and phase-locking alternated with chaos suggests frequency discrimination of the neuronal firing patterns. Furthermore, by mapping out Arnold tongues, we partition the amplitude-frequency parameter space in terms of the qualitative behaviors of the neuron. Thus the neuron's information (firing patterns) encodes the stimulus information (amplitude and frequency), and vice versa

Singularly perturbed Burger-Huxley equation: Analytical solution ...

African Journals Online (AJOL)

user

solutions of singularly perturbed nonlinear differential equations. ... for solving generalized Burgers-Huxley equation but this equation is not singularly ...... Solitary waves solutions of the generalized Burger Huxley equations, Journal of.

Optimal size of stochastic Hodgkin-Huxley neuronal systems for maximal energy efficiency in coding pulse signals

Science.gov (United States)

Yu, Lianchun; Liu, Liwei

2014-03-01

The generation and conduction of action potentials (APs) represents a fundamental means of communication in the nervous system and is a metabolically expensive process. In this paper, we investigate the energy efficiency of neural systems in transferring pulse signals with APs. By analytically solving a bistable neuron model that mimics the AP generation with a particle crossing the barrier of a double well, we find the optimal number of ion channels that maximizes the energy efficiency of a neuron. We also investigate the energy efficiency of a neuron population in which the input pulse signals are represented with synchronized spikes and read out with a downstream coincidence detector neuron. We find an optimal number of neurons in neuron population, as well as the number of ion channels in each neuron that maximizes the energy efficiency. The energy efficiency also depends on the characters of the input signals, e.g., the pulse strength and the interpulse intervals. These results are confirmed by computer simulation of the stochastic Hodgkin-Huxley model with a detailed description of the ion channel random gating. We argue that the tradeoff between signal transmission reliability and energy cost may influence the size of the neural systems when energy use is constrained.

Stochastic resonance on Newman-Watts networks of Hodgkin-Huxley neurons with local periodic driving

Energy Technology Data Exchange (ETDEWEB)

Ozer, Mahmut [Zonguldak Karaelmas University, Engineering Faculty, Department of Electrical and Electronics Engineering, 67100 Zonguldak (Turkey)], E-mail: mahmutozer2002@yahoo.com; Perc, Matjaz [University of Maribor, Faculty of Natural Sciences and Mathematics, Department of Physics, Koroska cesta 160, SI-2000 Maribor (Slovenia); Uzuntarla, Muhammet [Zonguldak Karaelmas University, Engineering Faculty, Department of Electrical and Electronics Engineering, 67100 Zonguldak (Turkey)

2009-03-02

We study the phenomenon of stochastic resonance on Newman-Watts small-world networks consisting of biophysically realistic Hodgkin-Huxley neurons with a tunable intensity of intrinsic noise via voltage-gated ion channels embedded in neuronal membranes. Importantly thereby, the subthreshold periodic driving is introduced to a single neuron of the network, thus acting as a pacemaker trying to impose its rhythm on the whole ensemble. We show that there exists an optimal intensity of intrinsic ion channel noise by which the outreach of the pacemaker extends optimally across the whole network. This stochastic resonance phenomenon can be further amplified via fine-tuning of the small-world network structure, and depends significantly also on the coupling strength among neurons and the driving frequency of the pacemaker. In particular, we demonstrate that the noise-induced transmission of weak localized rhythmic activity peaks when the pacemaker frequency matches the intrinsic frequency of subthreshold oscillations. The implications of our findings for weak signal detection and information propagation across neural networks are discussed.

Singularly perturbed Burger-Huxley equation: Analytical solution ...

African Journals Online (AJOL)

The work presented considers the initial boundary value problem for nonlinear singularly perturbed time dependent Burger- Huxley equation. The equation contains two terms with nonlinearities, the cubic term and the advection term. Generally, the severe difficulties of two types encounter in solving this problem. The first ...

Theoretical analysis of transcranial magneto-acoustical stimulation with Hodgkin–Huxley neuron model

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Yi eYuan

2016-04-01

Full Text Available Transcranial magneto-acoustical stimulation (TMAS is a novel stimulation technology in which an ultrasonic wave within a magnetostatic field generates an electric current in an area of interest in the brain to modulate neuronal activities. As a key part of the neural network, neurons transmit information in the nervous system. However, the effect of TMAS on the neuronal firing rhythm remains unknown. To address this problem, we investigated the stimulatory mechanism of TMAS on neurons with a Hodgkin-Huxley neuron model. The simulation results indicate that the magnetostatic field intensity and ultrasonic power can affect the amplitude and interspike interval of neuronal action potential under continuous wave ultrasound. The simulation results also show that the ultrasonic power, duty cycle and repetition frequency can alter the firing rhythm of neural action potential under pulsed ultrasound. This study can help to reveal and explain the biological mechanism of TMAS and to provide a theoretical basis for TMAS in the treatment or rehabilitation of neuropsychiatric disorders.

Non-linear leak currents affect mammalian neuron physiology

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Shiwei eHuang

2015-11-01

Full Text Available In their seminal works on squid giant axons, Hodgkin and Huxley approximated the membrane leak current as Ohmic, i.e. linear, since in their preparation, sub-threshold current rectification due to the influence of ionic concentration is negligible. Most studies on mammalian neurons have made the same, largely untested, assumption. Here we show that the membrane time constant and input resistance of mammalian neurons (when other major voltage-sensitive and ligand-gated ionic currents are discounted varies non-linearly with membrane voltage, following the prediction of a Goldman-Hodgkin-Katz-based passive membrane model. The model predicts that under such conditions, the time constant/input resistance-voltage relationship will linearize if the concentration differences across the cell membrane are reduced. These properties were observed in patch-clamp recordings of cerebellar Purkinje neurons (in the presence of pharmacological blockers of other background ionic currents and were more prominent in the sub-threshold region of the membrane potential. Model simulations showed that the non-linear leak affects voltage-clamp recordings and reduces temporal summation of excitatory synaptic input. Together, our results demonstrate the importance of trans-membrane ionic concentration in defining the functional properties of the passive membrane in mammalian neurons as well as other excitable cells.

Mathematical and numerical study of nonlinear boundary problems related to plasma physics

International Nuclear Information System (INIS)

Sermange, M.

1982-06-01

After the study of some equations based on the Hodgkin-Huxley model, the work presented here is concerned with nonlinear boundary problems in MHD. They are gathered in two subjects: equilibrium equations and stability equations. The axisymmetric MHD equilibrium equations with free boundary have been studied by different authors, particularly the existence, regularity, unicity and non-unicity. Here, bifurcation, convergence of calculation methods existence of solutions in a discontinuous frame are studied. MHD stability can be determined by the principle of Bernstein et al; the mathematical work concerned here bears on the equivalence, in the case of two-dimensional or axisymmetric stability, between this model and a scalar eigenvalue problem which is introduced. At last, modules for computing MHD equilibrium for the simulation of plasma confinement in a tokamak are described [fr

Efficient Spike-Coding with Multiplicative Adaptation in a Spike Response Model

NARCIS (Netherlands)

S.M. Bohte (Sander)

2012-01-01

htmlabstractNeural adaptation underlies the ability of neurons to maximize encoded informa- tion over a wide dynamic range of input stimuli. While adaptation is an intrinsic feature of neuronal models like the Hodgkin-Huxley model, the challenge is to in- tegrate adaptation in models of neural

Modelled temperature-dependent excitability behaviour of a generalised human peripheral sensory nerve fibre

CSIR Research Space (South Africa)

Smit, Jacoba E

2009-09-01

Full Text Available The objective of this study was to determine if a recently developed human Ranvier node model, which is based on a modified version of the Hodgkin-Huxley model, could predict the excitability behaviour in human peripheral sensory nerve fibres...

Computer Modelling of Functional Aspects of Noise in Endogenously Oscillating Neurons

Science.gov (United States)

Huber, M. T.; Dewald, M.; Voigt, K.; Braun, H. A.; Moss, F.

1998-03-01

Membrane potential oscillations are a widespread feature of neuronal activity. When such oscillations operate close to the spike-triggering threshold, noise can become an essential property of spike-generation. According to that, we developed a minimal Hodgkin-Huxley-type computer model which includes a noise term. This model accounts for experimental data from quite different cells ranging from mammalian cortical neurons to fish electroreceptors. With slight modifications of the parameters, the model's behavior can be tuned to bursting activity, which additionally allows it to mimick temperature encoding in peripheral cold receptors including transitions to apparently chaotic dynamics as indicated by methods for the detection of unstable periodic orbits. Under all conditions, cooperative effects between noise and nonlinear dynamics can be shown which, beyond stochastic resonance, might be of functional significance for stimulus encoding and neuromodulation.

Memristive Systems Analysis of 3-Terminal Devices

OpenAIRE

Mouttet, Blaise

2010-01-01

Memristive systems were proposed in 1976 by Leon Chua and Sung Mo Kang as a model for 2-terminal passive nonlinear dynamical systems which exhibit memory effects. Such systems were originally shown to be relevant to the modeling of action potentials in neurons in regards to the Hodgkin-Huxley model and, more recently, to the modeling of thin film materials such as TiO2-x proposed for non-volatile resistive memory. However, over the past 50 years a variety of 3-terminal non-passive dynamical d...

A numerical scheme for the generalized Burgers–Huxley equation

Directory of Open Access Journals (Sweden)

Brajesh K. Singh

2016-10-01

Full Text Available In this article, a numerical solution of generalized Burgers–Huxley (gBH equation is approximated by using a new scheme: modified cubic B-spline differential quadrature method (MCB-DQM. The scheme is based on differential quadrature method in which the weighting coefficients are obtained by using modified cubic B-splines as a set of basis functions. This scheme reduces the equation into a system of first-order ordinary differential equation (ODE which is solved by adopting SSP-RK43 scheme. Further, it is shown that the proposed scheme is stable. The efficiency of the proposed method is illustrated by four numerical experiments, which confirm that obtained results are in good agreement with earlier studies. This scheme is an easy, economical and efficient technique for finding numerical solutions for various kinds of (nonlinear physical models as compared to the earlier schemes.

Thomas Henry Huxley et la Bible Thomas Henry Huxley and the Bible

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Christophe Duvey

2009-10-01

Full Text Available Thomas Henry Huxley devoted several essays to the study of the Bible. This interest can only be accounted for if his ideas on history, religion as well as epistemology are examined. According to him, a struggle between free thought and supernaturalism was culminating during the Victorian era, hence the need for a “New Reformation” which was heir to the ideals of freedom defended by the humanists of the Renaissance. This movement opposed the principles of the supporters of what he called “ecclesiasticism”. The advocates of the “New Reformation” could rely on the progress of modern science, and agnosticism, which Huxley identified with scientific method, became its epistemological foundation. As a result, Huxley thought that the authority of physical science was in conflict with the infallibility of the Scriptures and with the theological arguments which rested on it, and this notably led him to the conclusion that the biblical narrative of the Flood was unhistorical. The naturalisation of the Scriptures seems then logically to follow his philosophical views based on the limits of human knowledge.It appears that it was the question of authority which underlay Huxley’s interest in the Bible. He thought that the authority of the Scriptures must be replaced by that of science.

'Great is Darwin and Bergson his poet': Julian Huxley's other evolutionary synthesis.

Science.gov (United States)

Herring, Emily

2018-01-01

In 1912, Julian Huxley published his first book The Individual in the Animal Kingdom which he dedicated to the then world-famous French philosopher Henri Bergson. Historians have generally adopted one of two attitudes towards Huxley's early encounter with Bergson. They either dismiss it entirely as unimportant or minimize it, deeming it a youthful indiscretion preceding Huxley's full conversion to Fisherian Darwinism. Close biographical study and archive materials demonstrate, however, that neither position is tenable. The study of the Bergsonian elements in play in Julian Huxley's early works fed into Huxley's first ideas about progress in evolution and even his celebrated theories of bird courtship. Furthermore, the view that Huxley rejected Bergson in his later years needs to be revised. Although Huxley ended up claiming that Bergson's theory of evolution had no explanatory power, he never repudiated the descriptive power of Bergson's controversial notion of the élan vital. Even into the Modern Synthesis period, Huxley represented his own synthesis as drawing decisively on Bergson's philosophy.

Modeling removal of accumulated potassium from T-tubules by inward rectifier potassium channels

NARCIS (Netherlands)

Wallinga, W.; Vliek, M.; Wienk, E.D.; Alberink, M.J.; Ypey, D.L.; Ypey, D.L.

1996-01-01

The membrane models of Cannon et al. (1993) and Alberink et al. (1995) for mammalian skeletal muscle fibers are based upon Hodgkin-Huxley descriptions of sodium, potassium delayed rectifier and leak conductances and the capacitive current taking into account fast inactivation of sodium channels. Now

A multiscale approach to modelling electrochemical processes occurring across the cell membrane with application to transmission of action potentials.

Science.gov (United States)

Richardson, G

2009-09-01

By application of matched asymptotic expansions, a simplified partial differential equation (PDE) model for the dynamic electrochemical processes occurring in the vicinity of a membrane, as ions selectively permeate across it, is formally derived from the Poisson-Nernst-Planck equations of electrochemistry. It is demonstrated that this simplified model reduces itself, in the limit of a long thin axon, to the cable equation used by Hodgkin and Huxley to describe the propagation of action potentials in the unmyelinated squid giant axon. The asymptotic reduction from the simplified PDE model to the cable equation leads to insights that are not otherwise apparent; these include an explanation of why the squid giant axon attains a diameter in the region of 1 mm. The simplified PDE model has more general application than the Hodgkin-Huxley cable equation and can, e.g. be used to describe action potential propagation in myelinated axons and neuronal cell bodies.

Impact of Bounded Noise and Rewiring on the Formation and Instability of Spiral Waves in a Small-World Network of Hodgkin-Huxley Neurons.

Science.gov (United States)

Yao, Yuangen; Deng, Haiyou; Ma, Chengzhang; Yi, Ming; Ma, Jun

2017-01-01

Spiral waves are observed in the chemical, physical and biological systems, and the emergence of spiral waves in cardiac tissue is linked to some diseases such as heart ventricular fibrillation and epilepsy; thus it has importance in theoretical studies and potential medical applications. Noise is inevitable in neuronal systems and can change the electrical activities of neuron in different ways. Many previous theoretical studies about the impacts of noise on spiral waves focus an unbounded Gaussian noise and even colored noise. In this paper, the impacts of bounded noise and rewiring of network on the formation and instability of spiral waves are discussed in small-world (SW) network of Hodgkin-Huxley (HH) neurons through numerical simulations, and possible statistical analysis will be carried out. Firstly, we present SW network of HH neurons subjected to bounded noise. Then, it is numerically demonstrated that bounded noise with proper intensity σ, amplitude A, or frequency f can facilitate the formation of spiral waves when rewiring probability p is below certain thresholds. In other words, bounded noise-induced resonant behavior can occur in the SW network of neurons. In addition, rewiring probability p always impairs spiral waves, while spiral waves are confirmed to be robust for small p, thus shortcut-induced phase transition of spiral wave with the increase of p is induced. Furthermore, statistical factors of synchronization are calculated to discern the phase transition of spatial pattern, and it is confirmed that larger factor of synchronization is approached with increasing of rewiring probability p, and the stability of spiral wave is destroyed.

Modeling of action potential generation in NG108-15 cells.

Science.gov (United States)

Molnar, Peter; Hickman, James J

2014-01-01

In order to explore the possibility of identifying toxins based on their effect on the shape of action potentials, we created a computer model of the action potential generation in NG108-15 cells (a neuroblastoma/glioma hybrid cell line). To generate the experimental data for model validation, voltage-dependent sodium, potassium and high-threshold calcium currents, as well as action potentials, were recorded from NG108-15 cells with conventional whole-cell patch-clamp methods. Based on the classic Hodgkin-Huxley formalism and the linear thermodynamic description of the rate constants, ion-channel parameters were estimated using an automatic fitting method. Utilizing the established parameters, action potentials were generated using the Hodgkin-Huxley formalism and were fitted to the recorded action potentials. To demonstrate the applicability of the method for toxin detection and discrimination, the effect of tetrodotoxin (a sodium channel blocker) and tefluthrin (a pyrethroid that is a sodium channel opener) were studied. The two toxins affected the shape of the action potentials differently, and their respective effects were identified based on the predicted changes in the fitted parameters.

Whistles, bells, and cogs in machines: Thomas Huxley and epiphenomenalism.

Science.gov (United States)

Greenwood, John

2010-01-01

In this paper I try to shed some historical light upon the doctrine of epiphenomenalism, by focusing on the version of epiphenomenalism championed by Thomas Huxley, which is often treated as a classic statement of the doctrine. I argue that it is doubtful if Huxley held any form of metaphysical epiphenomenalism, and that he held a more limited form of empirical epiphenomenalism with respect to consciousness but not with respect to mentality per se. Contrary to what is conventionally supposed, Huxley's empirical epiphenomenalism with respect to consciousness was not simply based upon the demonstration of the neurophysiological basis of conscious mentality, or derived from the extension of mechanistic and reflexive principles of explanation to encompass all forms of animal and human behavior, but was based upon the demonstration of purposive and coordinated animal and human behavior in the absence of consciousness. Given Huxley's own treatment of mentality, his characterization of animals and humans as "conscious automata" was not well chosen.

Author as a Corporal Subject of A. Huxley's Works

Science.gov (United States)

Falaleeva, Svetlana S.; Musaeva, Diana R.; Samoylova, Tatiana I.; Linnik, Anna M.

2016-01-01

The relevance of the problem studied in the article is conditioned by the fact that A. Huxley's works are regarded in the context of the modern theory of mimesis for the first time. The aim of the article is to analyze the author's problem as a corporal subject of Huxley's works in the context of the modern theory of mimesis. The leading method…

Acceleration of spiking neural network based pattern recognition on NVIDIA graphics processors.

Science.gov (United States)

Han, Bing; Taha, Tarek M

2010-04-01

There is currently a strong push in the research community to develop biological scale implementations of neuron based vision models. Systems at this scale are computationally demanding and generally utilize more accurate neuron models, such as the Izhikevich and the Hodgkin-Huxley models, in favor of the more popular integrate and fire model. We examine the feasibility of using graphics processing units (GPUs) to accelerate a spiking neural network based character recognition network to enable such large scale systems. Two versions of the network utilizing the Izhikevich and Hodgkin-Huxley models are implemented. Three NVIDIA general-purpose (GP) GPU platforms are examined, including the GeForce 9800 GX2, the Tesla C1060, and the Tesla S1070. Our results show that the GPGPUs can provide significant speedup over conventional processors. In particular, the fastest GPGPU utilized, the Tesla S1070, provided a speedup of 5.6 and 84.4 over highly optimized implementations on the fastest central processing unit (CPU) tested, a quadcore 2.67 GHz Xeon processor, for the Izhikevich and the Hodgkin-Huxley models, respectively. The CPU implementation utilized all four cores and the vector data parallelism offered by the processor. The results indicate that GPUs are well suited for this application domain.

A novel electrical model of nerve and muscle using Pspice

CERN Document Server

Peasgood, W; Lam, C K; Armstrong, A G; Wood, W

2003-01-01

In this work, a model is developed to simulate the biological processes involved in nerve fibre transmission and subsequent muscle contraction. The model has been based on approximating biological structure and function to electrical circuits and as such was implemented on an electronics simulation software package called Pspice. Models of nerve, the nerve-muscle interface and muscle fibre have been implemented. The time dependent ionic properties of the nerve and muscle membranes have been simulated using the Hodgkin-Huxley equations and for the muscle fibre, the implementation of the Huxley sliding filament theory for muscular contraction. The results show that nerve may be considered as a fractal transmission line and that the amplitude of the nerve membrane depolarization is dependent on the dimensions of the fibre. Additionally, simulation of the nerve-muscle interface allows the fractal nerve model to be connected to the muscle fibre model and it is shown that a two sarcomere molecular simulation can pr...

Chaos control and synchronization of two neurons exposed to ELF external electric field

International Nuclear Information System (INIS)

Wang Jiang; Zhang Ting; Che Yanqiu

2007-01-01

Chaos control and synchronization of two unidirectional coupled neurons exposed to ELF electrical field via nonlinear control technique is investigated. Based on results of space-time characteristics of trans-membrane voltage, the variation of cell trans-membrane voltage exposed to extremely low frequency (ELF) electric field is analyzed. The dynamical behaviors of the modified Hodgkin-Huxley (HH) model are identified under the periodic ELF electric field using both analytical and numerical analysis. Then, using the results of the analysis, a nonlinear feedback linearization control scheme and a modified adaptive control strategy are designed to synchronize the two unidirectional coupled neurons and stabilize the chaotic trajectory of the slave system to desired periodic orbit of the master system. The simulation results demonstrated the efficiency of the proposed algorithms

APPLICATION OF UKRAINIAN GRID INFRASTRUCTURE FOR INVESTIGATION OF NONLINEAR DYNAMICS IN LARGE NEURONAL NETWORKS

Directory of Open Access Journals (Sweden)

O. О. Sudakov

2015-12-01

Full Text Available In present work the Ukrainian National Grid (UNG infrastructure was applied for investigation of synchronization in large networks of interacting neurons. This application is important for solving of modern neuroscience problems related to mechanisms of nervous system activities (memory, cognition etc. and nervous pathologies (epilepsy, Parkinsonism, etc.. Modern non-linear dynamics theories and applications provides powerful basis for computer simulations of biological neuronal networks and investigation of phenomena which mechanisms hardly could be clarified by other approaches. Cubic millimeter of brain tissue contains about 105 neurons, so realistic (Hodgkin-Huxley model and phenomenological (Kuramoto-Sakaguchi, FitzHugh-Nagumo, etc. models simulations require consideration of large neurons numbers.

On the limit dynamics of systems with infinite multiple degrees of freedom

Energy Technology Data Exchange (ETDEWEB)

Braun, W A

1977-01-01

By using N/sup -2/ phi (g sub i - g sub j) regular pair interactions, it is shown that, for n approaching infinity, the Vlasovdynamics is the omega meson resonances -limit of the classical canonical N-particle-dynamics. Propagation of molecular chaos holds in this limit and the fluctuations converge to a Gaussian stochastic process, which is, however, non-Markovian. A model of a nerve membrane is studied in the limit of singular interaction with Fermion reservoirs. The resulting axon equations have the same structure as the Hodgkin Huxley equations. Recently proven theorems are used on nonlinear diffusion equations to show the existance of a propagating pulse solution.

Hybrid B-Spline Collocation Method for Solving the Generalized Burgers-Fisher and Burgers-Huxley Equations

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Imtiaz Wasim

2018-01-01

Full Text Available In this study, we introduce a new numerical technique for solving nonlinear generalized Burgers-Fisher and Burgers-Huxley equations using hybrid B-spline collocation method. This technique is based on usual finite difference scheme and Crank-Nicolson method which are used to discretize the time derivative and spatial derivatives, respectively. Furthermore, hybrid B-spline function is utilized as interpolating functions in spatial dimension. The scheme is verified unconditionally stable using the Von Neumann (Fourier method. Several test problems are considered to check the accuracy of the proposed scheme. The numerical results are in good agreement with known exact solutions and the existing schemes in literature.

Assessment of multiple frequency ELF electric and magnetic field exposure

International Nuclear Information System (INIS)

Leitgeb, N

2008-01-01

Electromagnetic fields both in daily life and at workplaces exhibit increasingly complex frequency spectra. Present spectral assessment rules proved to be too conservative for health risk assessment. This is because they are based on the assumption that cells would react like linear systems in terms of responding to a sum of frequencies by a sum of independent responses to each individual frequency. Based on numerical investigations with the Hodgkin-Huxley and the Frankenhaeuser-Huxley nerve cell models, it could be shown that accounting for the nonlinear behaviour of cellular excitation processes avoids considerable overestimation of simultaneous exposures to multiple frequency ELF electric and magnetic fields. Besides this, it could be shown that the role of phase relationships is less important than that assumed so far. The present assessment rules lead to non-compliances of marketed electric appliances. For general application, a nonlinear biology-based assessment (NBBA) rule has been proposed, validated and proven advantageous compared with ICNIRP's rule. While staying conservative it avoids unnecessary overestimation and demonstrates compliance even in cases of suspected non-conformities. It is up to responsible bodies to decide upon the adoption of this proposal and the potential need for implementing additional or reducing the already incorporated safety factors

expansion method for the Burgers, Burgers–Huxley and modified

Indian Academy of Sciences (India)

expansion method; Burgers equation; Burgers–Huxley equation; modified. Burgers–KdV equation .... Substituting the solution set (12) and the corresponding solutions of (4) into (8), we have ..... During the past several years, many have done.

The "History" of Victorian Scientific Naturalism: Huxley, Spencer and the "End" of natural history.

Science.gov (United States)

Lightman, Bernard

2016-08-01

As part of their defence of evolutionary theory, T. H. Huxley and Herbert Spencer argued that natural history was no longer a legitimate scientific discipline. They outlined a secularized concept of life from biology to argue for the validity of naturalism. Despite their support for naturalism, they offered two different responses to the decline of natural history. Whereas Huxley emphasized the creation of a biological discipline, and all that that entailed, Spencer was more concerned with constructing an entire intellectual system based on the idea of evolution. In effect, Spencer wanted to create a new scientific worldview based on evolutionary theory. This had consequences for their understanding of human history, especially of how science had evolved through the ages. It affected their conceptions of human agency, contingency, and directionality in history. Examining Huxley's and Spencer's responses to the "end" of natural history reveals some of the deep divisions within scientific naturalism and the inherent problems of naturalism in general. Whereas Huxley chose to separate the natural and the historical, Spencer opted to fuse them into a single system. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

Bistability induces episodic spike communication by inhibitory neurons in neuronal networks.

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Kazantsev, V B; Asatryan, S Yu

2011-09-01

Bistability is one of the important features of nonlinear dynamical systems. In neurodynamics, bistability has been found in basic Hodgkin-Huxley equations describing the cell membrane dynamics. When the neuron is clamped near its threshold, the stable rest potential may coexist with the stable limit cycle describing periodic spiking. However, this effect is often neglected in network computations where the neurons are typically reduced to threshold firing units (e.g., integrate-and-fire models). We found that the bistability may induce spike communication by inhibitory coupled neurons in the spiking network. The communication is realized in the form of episodic discharges with synchronous (correlated) spikes during the episodes. A spiking phase map is constructed to describe the synchronization and to estimate basic spike phase locking modes.

Treatment of Hodgkin`s disease; Tratamento da doenca de Hodgkin

Energy Technology Data Exchange (ETDEWEB)

Silva, E.M. [Instituto Estadual de Hematologia Arthur de Siqueira Cavalcanti, Rio de Janeiro, RJ (Brazil). Servico de Hematologia Clinica

1993-12-31

This study consists of a revision of the treatment and prognosis of Hodgkin`s disease, comparing the chemotherapeutic and radiotherapeutic therapy and the complications both as a direct result of the disease and a result of the treatment. (author). 34 refs, 1 tab.

Past as Prediction: Newcomb, Huxley, The Eclipse of Thales, and The Power of Science

Science.gov (United States)

Stanley, Matthew

2009-12-01

The ancient eclipse of Thales was an important, if peculiar, focus of scientific attention in the 19th century. Victorian-era astronomers first used it as data with which to calibrate their lunar theories, but its status became strangely malleable as the century progressed. The American astronomer Simon Newcomb re-examined the eclipse and rejected it as the basis for lunar theory. But strangely, it was the unprecedented accuracy of Newcomb's calculations that led the British biologist T.H. Huxley to declare the eclipse to be the quintessential example of the power of science. Huxley argued that astronomy's ability to create "retrospective prophecy” showed how scientific reasoning was superior to religion (and incidentally, helped support Darwin's theories). Both Newcomb and Huxley declared that prediction (of past and future) was what gave science its persuasive power. The eclipse of Thales's strange journey through Victorian astronomy reveals how these two influential scientists made the case for the social and cultural authority of science.

Hodgkin lymphoma

Science.gov (United States)

Lymphoma - Hodgkin; Hodgkin disease; Cancer - Hodgkin lymphoma ... to 70 years old. Past infection with the Epstein-Barr virus ( EBV ) is thought to contribute to some cases. People with HIV infection are at increased risk compared to the general population.

Memristor, Hodgkin–Huxley, and Edge of Chaos

International Nuclear Information System (INIS)

Chua, Leon

2013-01-01

From a pedagogical point of view, the memristor is defined in this tutorial as any 2-terminal device obeying a state-dependent Ohm’s law. This tutorial also shows that from an experimental point of view, the memristor can be defined as any 2-terminal device that exhibits the fingerprints of ‘pinched’ hysteresis loops in the v–i plane. It also shows that memristors endowed with a continuum of equilibrium states can be used as non-volatile analog memories. This tutorial shows that memristors span a much broader vista of complex phenomena and potential applications in many fields, including neurobiology. In particular, this tutorial presents toy memristors that can mimic the classic habituation and LTP learning phenomena. It also shows that sodium and potassium ion-channel memristors are the key to generating the action potential in the Hodgkin–Huxley equations, and that they are the key to resolving several unresolved anomalies associated with the Hodgkin–Huxley equations. This tutorial ends with an amazing new result derived from the new principle of local activity, which uncovers a minuscule life-enabling ‘Goldilocks zone’, dubbed the edge of chaos, where complex phenomena, including creativity and intelligence, may emerge. From an information processing perspective, this tutorial shows that synapses are locally-passive memristors, and that neurons are made of locally-active memristors. (tutorial)

On the identification of multiple space dependent ionic parameters in cardiac electrophysiology modelling

Science.gov (United States)

Abidi, Yassine; Bellassoued, Mourad; Mahjoub, Moncef; Zemzemi, Nejib

2018-03-01

In this paper, we consider the inverse problem of space dependent multiple ionic parameters identification in cardiac electrophysiology modelling from a set of observations. We use the monodomain system known as a state-of-the-art model in cardiac electrophysiology and we consider a general Hodgkin-Huxley formalism to describe the ionic exchanges at the microscopic level. This formalism covers many physiological transmembrane potential models including those in cardiac electrophysiology. Our main result is the proof of the uniqueness and a Lipschitz stability estimate of ion channels conductance parameters based on some observations on an arbitrary subdomain. The key idea is a Carleman estimate for a parabolic operator with multiple coefficients and an ordinary differential equation system.

Energy consumption in Hodgkin–Huxley type fast spiking neuron model exposed to an external electric field

Directory of Open Access Journals (Sweden)

K. Usha

2016-09-01

Full Text Available This paper evaluates the change in metabolic energy required to maintain the signalling activity of neurons in the presence of an external electric field. We have analysed the Hodgkin–Huxley type conductance based fast spiking neuron model as electrical circuit by changing the frequency and amplitude of the applied electric field. The study has shown that, the presence of electric field increases the membrane potential, electrical energy supply and metabolic energy consumption. As the amplitude of applied electric field increases by keeping a constant frequency, the membrane potential increases and consequently the electrical energy supply and metabolic energy consumption increases. On increasing the frequency of the applied field, the peak value of membrane potential after depolarization gradually decreases as a result electrical energy supply decreases which results in a lower rate of hydrolysis of ATP molecules.

Understanding the Electrical Behavior of the Action Potential in Terms of Elementary Electrical Sources

Science.gov (United States)

Rodriguez-Falces, Javier

2015-01-01

A concept of major importance in human electrophysiology studies is the process by which activation of an excitable cell results in a rapid rise and fall of the electrical membrane potential, the so-called action potential. Hodgkin and Huxley proposed a model to explain the ionic mechanisms underlying the formation of action potentials. However,…

Hodgkin lymphoma - children

Science.gov (United States)

... families share common experiences may help ease your stress. American Childhood Cancer Organization - www.acco.org Leukemia and ... Cancer - Hodgkin lymphoma - children; Childhood Hodgkin lymphoma ... Cancer Institute website. Childhood Hodgkin lymphoma treatment (PDQ) - health professional ...

Numerical investigation of action potential transmission in plants

Directory of Open Access Journals (Sweden)

Mariusz Pietruszka

2014-01-01

Full Text Available In context of a fairly concise review of recent literature and well established experimental results we reconsider the problem of action potential propagating steadily down the plant cell(s. Having adopted slightly modified Hodgkin-Huxley set of differential equations for the action potential we carried out the numerical investigation of these equations in the course of time. We argue that the Hodgkin-Huxley-Katz model for the nerve impulse can be used to describe the phenomena which take place in plants - this point of view seems to be plausible since the mechanisms involving active ionic transport across membranes from the mathematical point of view are similar. Besides, we compare in a qualitative way our theoretical outcomes with typical experimental results for the action potentials which arise as the reaction of plants to electrical, mechanical and light stimuli. Moreover, we point out the relevance of the sequence of events during the pulse with the appropriate ionic fluxes.

Hodgkin`s disease: internal mammary lymph nodes relapse diagnosed by Gallium-67 scintigraphy

Energy Technology Data Exchange (ETDEWEB)

Ruiz Hernandez, G.; Ampudia, J.; Castillo, F.J.; Romero, C. [Hospital Clinico Univ., Valencia (Spain). Servicio de Medicina Nuclear; Pallardo, Y. [Hospital Clinico Univ., Valencia (Spain). Servicio de Radiologia; Garcia Conde, J. [Hospital Clinico Univ., Valencia (Spain). Servicio de Hematologia y Oncologia Medica; Ramos, D. [Hospital Clinico Univ., Valencia (Spain). Servicio de Anatomia Patologica

1999-04-01

This article presents the case of a 62-year-old man with treated Hodgkin`s disease who had internal mammary lymph nodes relapse after a complete initial response. These masses were gallium avid. These findings were explained by histologically documented Hodgkin`s relapse, the first such case reported in that localization without chest wall involvement. The literature on mediastinal Hodgkin`s disease and diagnostic procedures are reviewed. (orig.) [Deutsch] Beschrieben wird der Fall eines 62jaehrigen Mannes, der nach initial erfolgreicher Therapie eines Morbus Hodgkin ein Lymphknotenrezidiv im Bereich der Brust aufweist. Die Lymphknoten reicherten Gallium an. Histologisch wurde das Hodgkinrezidiv gesichert. Es handelt sich um den ersten in diesem Bereich beschriebenen Fall ohne Infiltration der Brustwand. Die Literatur ueber mediastinalen Morbus Hodgkin und diagnostisches Vorgehen wurde ueberprueft. (orig.)

Toward Petascale Biologically Plausible Neural Networks

Science.gov (United States)

Long, Lyle

This talk will describe an approach to achieving petascale neural networks. Artificial intelligence has been oversold for many decades. Computers in the beginning could only do about 16,000 operations per second. Computer processing power, however, has been doubling every two years thanks to Moore's law, and growing even faster due to massively parallel architectures. Finally, 60 years after the first AI conference we have computers on the order of the performance of the human brain (1016 operations per second). The main issues now are algorithms, software, and learning. We have excellent models of neurons, such as the Hodgkin-Huxley model, but we do not know how the human neurons are wired together. With careful attention to efficient parallel computing, event-driven programming, table lookups, and memory minimization massive scale simulations can be performed. The code that will be described was written in C + + and uses the Message Passing Interface (MPI). It uses the full Hodgkin-Huxley neuron model, not a simplified model. It also allows arbitrary network structures (deep, recurrent, convolutional, all-to-all, etc.). The code is scalable, and has, so far, been tested on up to 2,048 processor cores using 107 neurons and 109 synapses.

Immunohistochemical Profile of Hodgkin and Non-Hodgkin Lymphoma

International Nuclear Information System (INIS)

Shahid, R.; Gulzar, R.; Avesi, L.; Hassan, S.; Danish, F.; Mirza, T.

2016-01-01

Objective: To analyze the frequencies of histological types of lymphoma, diagnosed with complete immunohistochemical profile in younger and older age group. Study Design: Cross-sectional analytical study. Place and Duration of Study: Dow Diagnostic Research and Reference Laboratory, Dow University of Health Sciences, Karachi, from January 2009 to September 2013. Methodology: Consecutive cases of lymphomas, which were diagnosed using immunohistochemistry, were analyzed according to WHO classification. Frequency and percentages for different types of lymphomas were calculated. Hodgkin and non-Hodgkin lymphomas characteristics in two age groups of less than and more than 40 years were compared, applying chi-square test. Results: Out of the 318 cases, 79 (25 percentage) were Hodgkin Lymphomas (HL) and 239 (75 percentage) were Non-Hodgkin Lymphomas (NHL). Mixed Cellularity Hodgkin Lymphoma (MCHL) was the commonest (n=48). Amongst the NHL, 215 (89.95 percentage) were B cell lymphomas and 24 (10.05percentage) were T-cell lymphomas. Diffuse Large B-Cell Lymphoma (DLBCL) was the commonest lymphoma (n=165, 69.95 percentage of NHL). Anaplastic T-Cell Lymphoma (ALCL, n=10) was the commonest T-cell lymphoma. The frequency of HL was significantly higher in the younger age group and that of NHL was higher in the older age group (p < 0.001). Primary lymph node involvement was reported in 175 (55 percentage) and cervical lymph node was the most frequent site. Extra nodal involvement was seen in 93 (29 percentage) of all cases and was reported in 87 (36.4 percentage) of NHL and 6 (7.5 percentage) of HL. The most common extra nodal site was the gastrointestinal tract. Conclusion: Hodgkin lymphoma comprises 25 percentage and non-Hodgkin lymphoma comprises 75 percentage of all lymphomas. Both occur in younger age groups than reported in the West. B-cell NHL is three times more common than T-cell lymphoma. DLBCL is the most frequent lymphoma. ALCL is the most common T-cell, and mixed

Integrable dissipative nonlinear second order differential equations via factorizations and Abel equations

Energy Technology Data Exchange (ETDEWEB)

Mancas, Stefan C. [Department of Mathematics, Embry–Riddle Aeronautical University, Daytona Beach, FL 32114-3900 (United States); Rosu, Haret C., E-mail: hcr@ipicyt.edu.mx [IPICYT, Instituto Potosino de Investigacion Cientifica y Tecnologica, Apdo Postal 3-74 Tangamanga, 78231 San Luis Potosí, SLP (Mexico)

2013-09-02

We emphasize two connections, one well known and another less known, between the dissipative nonlinear second order differential equations and the Abel equations which in their first-kind form have only cubic and quadratic terms. Then, employing an old integrability criterion due to Chiellini, we introduce the corresponding integrable dissipative equations. For illustration, we present the cases of some integrable dissipative Fisher, nonlinear pendulum, and Burgers–Huxley type equations which are obtained in this way and can be of interest in applications. We also show how to obtain Abel solutions directly from the factorization of second order nonlinear equations.

Coexistence between silent and bursting states in a biophysical Hodgkin-Huxley-type of model

DEFF Research Database (Denmark)

Stankevich, Nataliya; Mosekilde, Erik

2017-01-01

in a slightly modified, biophysical model that describe the dynamics of pancreatic beta-cells. To realize this form of coexistence, we have introduced an additional voltage-dependent potassium current that is activated in the region around the original, unstable equilibrium point. It is interesting to note...... that this modification also leads the model to display a blue-sky catastrophe in the transition region between chaotic and bursting states....

Modelling in vivo action potential propagation along a giant axon.

Science.gov (United States)

George, Stuart; Foster, Jamie M; Richardson, Giles

2015-01-01

A partial differential equation model for the three-dimensional current flow in an excitable, unmyelinated axon is considered. Where the axon radius is significantly below a critical value R(crit) (that depends upon intra- and extra-cellular conductivity and ion channel conductance) the resistance of the intracellular space is significantly higher than that of the extracellular space, such that the potential outside the axon is uniformly small whilst the intracellular potential is approximated by the transmembrane potential. In turn, since the current flow is predominantly axial, it can be shown that the transmembrane potential is approximated by a solution to the one-dimensional cable equation. It is noted that the radius of the squid giant axon, investigated by (Hodgkin and Huxley 1952e), lies close to R(crit). This motivates us to apply the three-dimensional model to the squid giant axon and compare the results thus found to those obtained using the cable equation. In the context of the in vitro experiments conducted in (Hodgkin and Huxley 1952e) we find only a small difference between the wave profiles determined using these two different approaches and little difference between the speeds of action potential propagation predicted. This suggests that the cable equation approximation is accurate in this scenario. However when applied to the it in vivo setting, in which the conductivity of the surrounding tissue is considerably lower than that of the axoplasm, there are marked differences in both wave profile and speed of action potential propagation calculated using the two approaches. In particular, the cable equation significantly over predicts the increase in the velocity of propagation as axon radius increases. The consequences of these results are discussed in terms of the evolutionary costs associated with increasing the speed of action potential propagation by increasing axon radius.

Results on a Binding Neuron Model and Their Implications for Modified Hourglass Model for Neuronal Network

Directory of Open Access Journals (Sweden)

Viswanathan Arunachalam

2013-01-01

Full Text Available The classical models of single neuron like Hodgkin-Huxley point neuron or leaky integrate and fire neuron assume the influence of postsynaptic potentials to last till the neuron fires. Vidybida (2008 in a refreshing departure has proposed models for binding neurons in which the trace of an input is remembered only for a finite fixed period of time after which it is forgotten. The binding neurons conform to the behaviour of real neurons and are applicable in constructing fast recurrent networks for computer modeling. This paper develops explicitly several useful results for a binding neuron like the firing time distribution and other statistical characteristics. We also discuss the applicability of the developed results in constructing a modified hourglass network model in which there are interconnected neurons with excitatory as well as inhibitory inputs. Limited simulation results of the hourglass network are presented.

Hodgkin's sygdom--et histologisk problem

DEFF Research Database (Denmark)

Lauritzen, A F; Specht, L; Nissen, N I

1989-01-01

Since the Rye classification of Hodgkin's disease, many lesions which resemble Hodgkin's disease microscopically have been described. The histological features of Hodgkin's disease, including the BNLI subclassification of nodular sclerosis, and the lesions which resemble Hodgkin's disease microsc...

Spiking sychronization regulated by noise in three types of Hodgkin—Huxley neuronal networks

International Nuclear Information System (INIS)

Zhang Zheng-Zhen; Zeng Shang-You; Tang Wen-Yan; Hu Jin-Lin; Zeng Shao-Wen; Ning Wei-Lian; Qiu Yi; Wu Hui-Si

2012-01-01

In this paper, we study spiking synchronization in three different types of Hodgkin—Huxley neuronal networks, which are the small-world, regular, and random neuronal networks. All the neurons are subjected to subthreshold stimulus and external noise. It is found that in each of all the neuronal networks there is an optimal strength of noise to induce the maximal spiking synchronization. We further demonstrate that in each of the neuronal networks there is a range of synaptic conductance to induce the effect that an optimal strength of noise maximizes the spiking synchronization. Only when the magnitude of the synaptic conductance is moderate, will the effect be considerable. However, if the synaptic conductance is small or large, the effect vanishes. As the connections between neurons increase, the synaptic conductance to maximize the effect decreases. Therefore, we show quantitatively that the noise-induced maximal synchronization in the Hodgkin—Huxley neuronal network is a general effect, regardless of the specific type of neuronal network

Stages of Childhood Hodgkin Lymphoma

Science.gov (United States)

... Version Key Points Childhood Hodgkin lymphoma is a disease in which malignant (cancer) cells form in the lymph system. There are two types of childhood Hodgkin lymphoma. Epstein-Barr virus infection increases the risk of childhood Hodgkin ...

Non-Hodgkin's lymphomas

International Nuclear Information System (INIS)

Glatstein, E.; Wasserman, T.H.

1987-01-01

Non-Hodgkin's lymphomas are a varied and complex group of diseases that must be distinguished from Hodgkin's disease. The latter almost always begins in lymph nodes and spreads primarily in an axial fashion; non-Hodgkin's lymphomas may begin either in lymph nodes or in extranodal tissue and can spread both in an axial fashion and centrifugally. Because of changes in pathology terminology and the introduction of a classification using cell surface markers, many prognostic groups of patients with lymphomas have evolved. Therapeutic choices and prognosis are greatly influenced by variations in anatomic sites and extent of disease. Currently, the decisions on management require a balancing of radiation therapy with systemic chemotherapy. In some cases, radiation therapy alone may be sufficient; however, because most patients with non-Hodgkins's lymphomas tend to have advanced disease, a large percentage of patients will be managed with chemotherapy alone or in combination with radiation therapy

Radiation-induced splenic atrophy in patients with Hodgkin's disease and non-Hodgkin's lymphomas

International Nuclear Information System (INIS)

Dailey, M.O.; Coleman, C.N.; Kaplan, H.S.

1980-01-01

Effective treatment of Hodgkin's disease requires the determination of the extent of the disease. This usually involves staging laparotomy, which includes splenectomy and biopsies of the para-aortic lymph nodes, liver, and bone marrow. Absence of the spleen predisposes a person to fulminant septicemia from encapsulated bacteria, a risk even greater in patients undergoing treatment for Hodgkin's disease. For this reason, some investigators have suggested that spleens not be removed for diagnosis but, rather, that they be included within the fields of radiation, which would preserve normal splenic function. We present a case of fatal spontaneous pneumococcal sepsis in a patient with splenic atrophy; the sepsis occurred 12 years after successful treatment of Hodgkin's disease by total nodal and splenic irradiation. A retrospective study of patients treated for Hodgkin's and non-Hodgkin's lymphomas indicated that atrophy and functional asplenia may be an important sequela of splenic irradiation

Pediatric Hodgkin's disease - up, up, and beyond

International Nuclear Information System (INIS)

Donaldson, Sarah S.

2002-01-01

Juan A. del Regato, 1909-1999, was a superb clinician-educator who recognized the radiocurability of Hodgkin's disease but questioned treatment without late effects, particularly in children. The remarkable progress in pediatric Hodgkin's disease today is a tribute to this influential pioneer, who served as a role model to many. Combined modality therapy using low-dose, involved-field radiation and multiagent chemotherapy today results in a 5-year relative survival rate of 94% among American children with Hodgkin's disease. However, several areas hold promise for future advances, including a new pathology classification and biology studies that distinguish classic Hodgkin's disease from other lymphomas; new noninvasive staging techniques, including 18F-fluorodeoxyglucose-positron emission tomography; the definition of risk groups to segregate low-, intermediate-, and high-risk groups on the basis of a prognostic index, facilitating risk-adapted therapy; and myeloablative therapy followed by hematopoietic stem cell transplantation. Currently used for children with relapse, it is associated with a 5-year survival of 65% and should be considered as the initial therapy for high-risk groups. Idiopathic diffuse pulmonary toxicity after autologous transplantation is high among children with an atopic history; thus, atopy should be considered when selecting children appropriate for transplantation. Finally, novel therapies, such as the anti-CD20 antibody, rituximab, may be useful for children with CD20+, lymphocyte-predominant Hodgkin's disease. The universal goal of cure without late effects is realistic for almost all children with Hodgkin's disease today

Chimera States in Neural Oscillators

Science.gov (United States)

Bahar, Sonya; Glaze, Tera

2014-03-01

Chimera states have recently been explored both theoretically and experimentally, in various coupled nonlinear oscillators, ranging from phase-oscillator models to coupled chemical reactions. In a chimera state, both coherent and incoherent (or synchronized and desynchronized) states occur simultaneously in populations of identical oscillators. We investigate chimera behavior in a population of neural oscillators using the Huber-Braun model, a Hodgkin-Huxley-like model originally developed to characterize the temperature-dependent bursting behavior of mammalian cold receptors. One population of neurons is allowed to synchronize, with each neuron receiving input from all the others in its group (global within-group coupling). Subsequently, a second population of identical neurons is placed under an identical global within-group coupling, and the two populations are also coupled to each other (between-group coupling). For certain values of the coupling constants, the neurons in the two populations exhibit radically different synchronization behavior. We will discuss the range of chimera activity in the model, and discuss its implications for actual neural activity, such as unihemispheric sleep.

Physiological models of the lateral superior olive.

Directory of Open Access Journals (Sweden)

Go Ashida

2017-12-01

Full Text Available In computational biology, modeling is a fundamental tool for formulating, analyzing and predicting complex phenomena. Most neuron models, however, are designed to reproduce certain small sets of empirical data. Hence their outcome is usually not compatible or comparable with other models or datasets, making it unclear how widely applicable such models are. In this study, we investigate these aspects of modeling, namely credibility and generalizability, with a specific focus on auditory neurons involved in the localization of sound sources. The primary cues for binaural sound localization are comprised of interaural time and level differences (ITD/ILD, which are the timing and intensity differences of the sound waves arriving at the two ears. The lateral superior olive (LSO in the auditory brainstem is one of the locations where such acoustic information is first computed. An LSO neuron receives temporally structured excitatory and inhibitory synaptic inputs that are driven by ipsi- and contralateral sound stimuli, respectively, and changes its spike rate according to binaural acoustic differences. Here we examine seven contemporary models of LSO neurons with different levels of biophysical complexity, from predominantly functional ones ('shot-noise' models to those with more detailed physiological components (variations of integrate-and-fire and Hodgkin-Huxley-type. These models, calibrated to reproduce known monaural and binaural characteristics of LSO, generate largely similar results to each other in simulating ITD and ILD coding. Our comparisons of physiological detail, computational efficiency, predictive performances, and further expandability of the models demonstrate (1 that the simplistic, functional LSO models are suitable for applications where low computational costs and mathematical transparency are needed, (2 that more complex models with detailed membrane potential dynamics are necessary for simulation studies where sub

Potential benefits of therapeutic splenectomy for patients with Hodgkin's disease and non-Hodgkin's lymphomas

International Nuclear Information System (INIS)

Schreiber, D.P.; Jacobs, C.; Rosenberg, S.A.; Cox, R.S.; Hoppe, R.T.

1985-01-01

Thirty-four patients with Hodgkin's disease and non-Hodgkin's lymphoma underwent therapeutic splenectomies to improve hematologic tolerance for chemotherapy. The mean age was 40 years; there were 16 males and 18 females. Fourteen had Hodgkin's disease, 19 had non-Hodgkin's lymphoma, and 1 had malignant histocytosis. Nineteen had palpable splenomegaly, 19 had marrow involvement and 20 had splenic involvement by lymphoma. The following data were analyzed before and after splenectomy: mean white blood cell count (WBC) and platelet count on planned first day of cycle, delay ratio of chemotherapy delivery and percent maximal dose rate. Thirteen patients had non-Hodgkin's lymphoma, splenomegaly and positive bone marrow and showed significant benefit in all of the aforementioned parameters. Of the patients with prior irradiation, only those who completed their radiation greater than six months prior to splenectomy showed benefit. Ten patients had Hodgkin's disease, negative bone marrow and no splenomegaly. This group showed significant improvement in mean platelet count but more limited benefit in delay ratio and percent maximal dose rate. Thus, selected patients with lymphoma who are experiencing delays in chemotherapy because of poor count tolerance may benefit from splenectomy

Mode-locking behavior of Izhikevich neurons under periodic external forcing

Science.gov (United States)

Farokhniaee, AmirAli; Large, Edward W.

2017-06-01

Many neurons in the auditory system of the brain must encode periodic signals. These neurons under periodic stimulation display rich dynamical states including mode locking and chaotic responses. Periodic stimuli such as sinusoidal waves and amplitude modulated sounds can lead to various forms of n :m mode-locked states, in which a neuron fires n action potentials per m cycles of the stimulus. Here, we study mode-locking in the Izhikevich neurons, a reduced model of the Hodgkin-Huxley neurons. The Izhikevich model is much simpler in terms of the dimension of the coupled nonlinear differential equations compared with other existing models, but excellent for generating the complex spiking patterns observed in real neurons. We obtained the regions of existence of the various mode-locked states on the frequency-amplitude plane, called Arnold tongues, for the Izhikevich neurons. Arnold tongue analysis provides useful insight into the organization of mode-locking behavior of neurons under periodic forcing. We find these tongues for both class-1 and class-2 excitable neurons in both deterministic and noisy regimes.

Spike Neural Models Part II: Abstract Neural Models

Directory of Open Access Journals (Sweden)

Johnson, Melissa G.

2018-02-01

Full Text Available Neurons are complex cells that require a lot of time and resources to model completely. In spiking neural networks (SNN though, not all that complexity is required. Therefore simple, abstract models are often used. These models save time, use less computer resources, and are easier to understand. This tutorial presents two such models: Izhikevich's model, which is biologically realistic in the resulting spike trains but not in the parameters, and the Leaky Integrate and Fire (LIF model which is not biologically realistic but does quickly and easily integrate input to produce spikes. Izhikevich's model is based on Hodgkin-Huxley's model but simplified such that it uses only two differentiation equations and four parameters to produce various realistic spike patterns. LIF is based on a standard electrical circuit and contains one equation. Either of these two models, or any of the many other models in literature can be used in a SNN. Choosing a neural model is an important task that depends on the goal of the research and the resources available. Once a model is chosen, network decisions such as connectivity, delay, and sparseness, need to be made. Understanding neural models and how they are incorporated into the network is the first step in creating a SNN.

LDRD report nonlinear model reduction

Energy Technology Data Exchange (ETDEWEB)

Segalman, D.; Heinstein, M.

1997-09-01

The very general problem of model reduction of nonlinear systems was made tractable by focusing on the very large subclass consisting of linear subsystems connected by nonlinear interfaces. Such problems constitute a large part of the nonlinear structural problems encountered in addressing the Sandia missions. A synthesis approach to this class of problems was developed consisting of: detailed modeling of the interface mechanics; collapsing the interface simulation results into simple nonlinear interface models; constructing system models by assembling model approximations of the linear subsystems and the nonlinear interface models. These system models, though nonlinear, would have very few degrees of freedom. A paradigm problem, that of machine tool vibration, was selected for application of the reduction approach outlined above. Research results achieved along the way as well as the overall modeling of a specific machine tool have been very encouraging. In order to confirm the interface models resulting from simulation, it was necessary to develop techniques to deduce interface mechanics from experimental data collected from the overall nonlinear structure. A program to develop such techniques was also pursued with good success.

Hodgkin Lymphoma (For Kids)

Science.gov (United States)

... First Aid & Safety Doctors & Hospitals Videos Recipes for Kids Kids site Sitio para niños How the Body Works ... Educators Search English Español Hodgkin Lymphoma KidsHealth / For Kids / Hodgkin Lymphoma What's in this article? What Is ...

Epstein-Barr Virus in Classical Hodgkin Lymphoma

International Nuclear Information System (INIS)

Azhar, M.; Din, H. U.; Muhammad, I.; Hashmi, S. N.; Akhtar, F.

2016-01-01

Background: Epstein-Barr virus plays an important role in pathogenesis of Hodgkin lymphoma. The first patient with Epstein-Barr positive Reed Sternberg cells was described in 1985. Since then association between Epstein-Barr virus and Hodgkin lymphoma has been shown in many parts of the world and its occurrence shows significant variation from continent to continent and from country to country. Method: The study was carried out at department of histopathology, Armed Forces Institute of Pathology from 27th April 2013 to 10th March 2014. A total of 55 cases of classical Hodgkin lymphoma were included in the study. Results: Out of 55 patients, 38 (69 percent) were male and 17 (31 percent) were female. The age of the patients ranged between 4-67 years with an average age of 29.4±21.72 years. Out of these, 44 cases (80 percent) were positive for latent membrane protein-1. Among positive cases 32 (72.72 percent) were male and 12 (27.28 percent) were female. Based upon histological subtypes MCHL was the commonest as a whole accounting for 87.3 percent as well as among both genders. Out of total 55 cases, 79.16 percent (38/48) of mixed cellularity Hodgkin lymphoma cases showed positivity for latent membrane protein-1 while 83.33 percent (5/6) cases of nodular sclerosis Hodgkin lymphoma and 100 percent (1/1) cases of lymphocyte depleted Hodgkin lymphoma showed positivity. No case of lymphocyte predominant classical Hodgkin lymphoma was diagnosed during the study. 80 percent of our classical Hodgkin lymphoma cases showed association with EBV expression. A total of 79.16 percent cases of mixed cellularity Hodgkin lymphoma showed LMP1 expression while 100 percent of lymphocyte depleted Hodgkin lymphoma showed LMP1 expression. Conclusion: The highest expression seen in lymphocyte depleted Hodgkin lymphoma subtype in contrast to mixed cellularity requires to be confirmed by a larger scale study comprising of substantial number of patients of lymphocyte depleted Hodgkin lymphoma

Special issue on Computational Neuroscience - PREFACE

DEFF Research Database (Denmark)

Ditlevsen, Susanne; Lansky, Petr

2014-01-01

This Special Issue of Mathematical Biosciences and Engineering contains ten selected papers presented at the Neural Coding 2012 workshop. Neuroscience is traditionally very close to mathematics which stems from the famous theoretical work of McCulloch--Pitts and Hodgkin--Huxley in the middle...

Calculus for cognitive scientists partial differential equation models

CERN Document Server

Peterson, James K

2016-01-01

This book shows cognitive scientists in training how mathematics, computer science and science can be usefully and seamlessly intertwined. It is a follow-up to the first two volumes on mathematics for cognitive scientists, and includes the mathematics and computational tools needed to understand how to compute the terms in the Fourier series expansions that solve the cable equation. The latter is derived from first principles by going back to cellular biology and the relevant biophysics.  A detailed discussion of ion movement through cellular membranes, and an explanation of how the equations that govern such ion movement leading to the standard transient cable equation are included. There are also solutions for the cable model using separation of variables, as well an explanation of why Fourier series converge and a description of the implementation of MatLab tools to compute the solutions. Finally, the standard Hodgkin - Huxley model is developed for an excitable neuron and is solved using MatLab.

Generalized Nonlinear Yule Models

OpenAIRE

Lansky, Petr; Polito, Federico; Sacerdote, Laura

2016-01-01

With the aim of considering models with persistent memory we propose a fractional nonlinear modification of the classical Yule model often studied in the context of macrovolution. Here the model is analyzed and interpreted in the framework of the development of networks such as the World Wide Web. Nonlinearity is introduced by replacing the linear birth process governing the growth of the in-links of each specific webpage with a fractional nonlinear birth process with completely general birth...

Iodine I 131 Monoclonal Antibody BC8 Before Autologous Stem Cell Transplant in Treating Patients With Relapsed or Refractory Hodgkin Lymphoma or Non-Hodgkin Lymphoma

Science.gov (United States)

2017-11-15

Recurrent B-Cell Non-Hodgkin Lymphoma; Recurrent Hodgkin Lymphoma; Recurrent T-Cell Non-Hodgkin Lymphoma; Refractory B-Cell Non-Hodgkin Lymphoma; Refractory Hodgkin Lymphoma; Refractory T-Cell Non-Hodgkin Lymphoma

Modeling nonlinearities in MEMS oscillators.

Science.gov (United States)

Agrawal, Deepak K; Woodhouse, Jim; Seshia, Ashwin A

2013-08-01

We present a mathematical model of a microelectromechanical system (MEMS) oscillator that integrates the nonlinearities of the MEMS resonator and the oscillator circuitry in a single numerical modeling environment. This is achieved by transforming the conventional nonlinear mechanical model into the electrical domain while simultaneously considering the prominent nonlinearities of the resonator. The proposed nonlinear electrical model is validated by comparing the simulated amplitude-frequency response with measurements on an open-loop electrically addressed flexural silicon MEMS resonator driven to large motional amplitudes. Next, the essential nonlinearities in the oscillator circuit are investigated and a mathematical model of a MEMS oscillator is proposed that integrates the nonlinearities of the resonator. The concept is illustrated for MEMS transimpedance-amplifier- based square-wave and sine-wave oscillators. Closed-form expressions of steady-state output power and output frequency are derived for both oscillator models and compared with experimental and simulation results, with a good match in the predicted trends in all three cases.

Dorothy Crowfoot Hodgkin

Science.gov (United States)

Montalvo, Jessica

2009-10-01

Born in 1910 in Cairo, Egypt, Dorothy Crowfoot Hodgkin would later be known as the third woman in history to win the Nobel Prize in Chemistry for her research on the structure of vitamin B-12. Her X-ray crystallography work also included discovering the molecular structure of penicillin and insulin. Dr. Hodgkin's work has aided in determining the structures of molecules for others to expand the technology necessary for today's medicine.

Evaluation of nonlinearity and validity of nonlinear modeling for complex time series.

Science.gov (United States)

Suzuki, Tomoya; Ikeguchi, Tohru; Suzuki, Masuo

2007-10-01

Even if an original time series exhibits nonlinearity, it is not always effective to approximate the time series by a nonlinear model because such nonlinear models have high complexity from the viewpoint of information criteria. Therefore, we propose two measures to evaluate both the nonlinearity of a time series and validity of nonlinear modeling applied to it by nonlinear predictability and information criteria. Through numerical simulations, we confirm that the proposed measures effectively detect the nonlinearity of an observed time series and evaluate the validity of the nonlinear model. The measures are also robust against observational noises. We also analyze some real time series: the difference of the number of chickenpox and measles patients, the number of sunspots, five Japanese vowels, and the chaotic laser. We can confirm that the nonlinear model is effective for the Japanese vowel /a/, the difference of the number of measles patients, and the chaotic laser.

Stages of Adult Hodgkin Lymphoma

Science.gov (United States)

... Lymphocyte-rich classical Hodgkin lymphoma. Age, gender, and Epstein-Barr infection can affect the risk of adult Hodgkin lymphoma. Anything that increases your risk of getting a disease is called a risk factor . Having a risk ...

Nonlinear 2D arm dynamics in response to continuous and pulse-shaped force perturbations.

Science.gov (United States)

Happee, Riender; de Vlugt, Erwin; van Vliet, Bart

2015-01-01

Ample evidence exists regarding the nonlinearity of the neuromuscular system but linear models are widely applied to capture postural dynamics. This study quantifies the nonlinearity of human arm postural dynamics applying 2D continuous force perturbations (0.2-40 Hz) inducing three levels of hand displacement (5, 15, 45 mm RMS) followed by force-pulse perturbations inducing large hand displacements (up to 250 mm) in a position task (PT) and a relax task (RT) recording activity of eight shoulder and elbow muscles. The continuous perturbation data were used to analyze the 2D endpoint dynamics in the frequency domain and to identify reflexive and intrinsic parameters of a linear neuromuscular shoulder-elbow model. Subsequently, it was assessed to what extent the large displacements in response to force pulses could be predicted from the 'small amplitude' linear neuromuscular model. Continuous and pulse perturbation responses with varying amplitudes disclosed highly nonlinear effects. In PT, a larger continuous perturbation induced stiffening with a factor of 1.5 attributed to task adaptation evidenced by increased co-contraction and reflexive activity. This task adaptation was even more profound in the pulse responses where reflexes and displacements were strongly affected by the presence and amplitude of preceding continuous perturbations. In RT, a larger continuous perturbation resulted in yielding with a factor of 3.8 attributed to nonlinear mechanical properties as no significant reflexive activity was found. Pulse perturbations always resulted in yielding where a model fitted to the preceding 5-mm continuous perturbations predicted only 37% of the recorded peak displacements in RT and 79% in PT. This demonstrates that linear neuromuscular models, identified using continuous perturbations with small amplitudes, strongly underestimate displacements in pulse-shaped (e.g., impact) loading conditions. The data will be used to validate neuromuscular models including

A Neuron-Based Model of Sleep-Wake Cycles

Science.gov (United States)

Postnova, Svetlana; Peters, Achim; Braun, Hans

2008-03-01

In recent years it was discovered that a neuropeptide orexin/hypocretin plays a main role in sleep processes. This peptide is produced by the neurons in the lateral hypothalamus, which project to almost all brain areas. We present a computational model of sleep-wake cycles, which is based on the Hodgkin-Huxley type neurons and considers reciprocal glutaminergic projections between the lateral hypothalamus and the prefrontal cortex. Orexin is released as a neuromodulator and is required to keep the neurons firing, which corresponds to the wake state. When orexin is depleted the neurons are getting silent as observed in the sleep state. They can be reactivated by the circadian signal from the suprachiasmatic nucleus and/or external stimuli (alarm clock). Orexin projections to the thalamocortical neurons also can account for their transition from tonic firing activity during wakefulness to synchronized burst discharges during sleep.

Hodgkin's Lymphoma of the Breast

African Journals Online (AJOL)

TNHJOURNALPH

RESULT. A tissue diagnosis of Hodgkin's lymphoma with typical ... It was the first cancer to be cured ... ultrasonography showed enlarged liver. The .... McMillan A, Horning S. Non-Hodgkins lymphoma of the Breast. Cancer. 2007;110:25-30. 5.

Biophysically realistic minimal model of dopamine neuron

Science.gov (United States)

Oprisan, Sorinel

2008-03-01

We proposed and studied a new biophysically relevant computational model of dopaminergic neurons. Midbrain dopamine neurons are involved in motivation and the control of movement, and have been implicated in various pathologies such as Parkinson's disease, schizophrenia, and drug abuse. The model we developed is a single-compartment Hodgkin-Huxley (HH)-type parallel conductance membrane model. The model captures the essential mechanisms underlying the slow oscillatory potentials and plateau potential oscillations. The main currents involved are: 1) a voltage-dependent fast calcium current, 2) a small conductance potassium current that is modulated by the cytosolic concentration of calcium, and 3) a slow voltage-activated potassium current. We developed multidimensional bifurcation diagrams and extracted the effective domains of sustained oscillations. The model includes a calcium balance due to the fundamental importance of calcium influx as proved by simultaneous electrophysiological and calcium imaging procedure. Although there are significant evidences to suggest a partially electrogenic calcium pump, all previous models considered only elecrtogenic pumps. We investigated the effect of the electrogenic calcium pump on the bifurcation diagram of the model and compared our findings against the experimental results.

Hodgkin's disease in pregnancy

International Nuclear Information System (INIS)

Szelc, S.; Szeliga, E.

1993-01-01

Pregnancy outcome and its influence on the effect of the MOPP chemotherapy for 30 patients with Hodgkin's disease were analyzed. During the first 6 months after completing the treatment 305 of pregnancies were interrupted. Pregnancy during complete remission of Hodgkin's disease after combined treatment does not increase the risk of relapse and is not a risk to delivery and foetus. (author)

ATR alterations in Hodgkin's lymphoma

NARCIS (Netherlands)

Liu, Angen; Takakuwa, Tetsuya; Fujita, Shigeki; Luo, Wen-Juan; Tresnasari, Kristianti; Van den Berg, Anke; Poppema, Sibrand; Aozasa, Katsuyuki

Hodgkin's lymphoma (HL) is characterized by the presence of neoplastic Hodgkin and Reed-Sternberg cells (HRSC) in a background of inflammatory cells. Free radicals and oxidative stress generated in the inflammatory lesions could cause DNA damage, thus providing a basis for lymphomagenesis.

Nonlinear Modeling by Assembling Piecewise Linear Models

Science.gov (United States)

Yao, Weigang; Liou, Meng-Sing

2013-01-01

To preserve nonlinearity of a full order system over a parameters range of interest, we propose a simple modeling approach by assembling a set of piecewise local solutions, including the first-order Taylor series terms expanded about some sampling states. The work by Rewienski and White inspired our use of piecewise linear local solutions. The assembly of these local approximations is accomplished by assigning nonlinear weights, through radial basis functions in this study. The efficacy of the proposed procedure is validated for a two-dimensional airfoil moving at different Mach numbers and pitching motions, under which the flow exhibits prominent nonlinear behaviors. All results confirm that our nonlinear model is accurate and stable for predicting not only aerodynamic forces but also detailed flowfields. Moreover, the model is robustness-accurate for inputs considerably different from the base trajectory in form and magnitude. This modeling preserves nonlinearity of the problems considered in a rather simple and accurate manner.

A bivariate Chebyshev spectral collocation quasilinearization method for nonlinear evolution parabolic equations.

Science.gov (United States)

Motsa, S S; Magagula, V M; Sibanda, P

2014-01-01

This paper presents a new method for solving higher order nonlinear evolution partial differential equations (NPDEs). The method combines quasilinearisation, the Chebyshev spectral collocation method, and bivariate Lagrange interpolation. In this paper, we use the method to solve several nonlinear evolution equations, such as the modified KdV-Burgers equation, highly nonlinear modified KdV equation, Fisher's equation, Burgers-Fisher equation, Burgers-Huxley equation, and the Fitzhugh-Nagumo equation. The results are compared with known exact analytical solutions from literature to confirm accuracy, convergence, and effectiveness of the method. There is congruence between the numerical results and the exact solutions to a high order of accuracy. Tables were generated to present the order of accuracy of the method; convergence graphs to verify convergence of the method and error graphs are presented to show the excellent agreement between the results from this study and the known results from literature.

A Bivariate Chebyshev Spectral Collocation Quasilinearization Method for Nonlinear Evolution Parabolic Equations

Directory of Open Access Journals (Sweden)

S. S. Motsa

2014-01-01

Full Text Available This paper presents a new method for solving higher order nonlinear evolution partial differential equations (NPDEs. The method combines quasilinearisation, the Chebyshev spectral collocation method, and bivariate Lagrange interpolation. In this paper, we use the method to solve several nonlinear evolution equations, such as the modified KdV-Burgers equation, highly nonlinear modified KdV equation, Fisher's equation, Burgers-Fisher equation, Burgers-Huxley equation, and the Fitzhugh-Nagumo equation. The results are compared with known exact analytical solutions from literature to confirm accuracy, convergence, and effectiveness of the method. There is congruence between the numerical results and the exact solutions to a high order of accuracy. Tables were generated to present the order of accuracy of the method; convergence graphs to verify convergence of the method and error graphs are presented to show the excellent agreement between the results from this study and the known results from literature.

Adaptive regression for modeling nonlinear relationships

CERN Document Server

Knafl, George J

2016-01-01

This book presents methods for investigating whether relationships are linear or nonlinear and for adaptively fitting appropriate models when they are nonlinear. Data analysts will learn how to incorporate nonlinearity in one or more predictor variables into regression models for different types of outcome variables. Such nonlinear dependence is often not considered in applied research, yet nonlinear relationships are common and so need to be addressed. A standard linear analysis can produce misleading conclusions, while a nonlinear analysis can provide novel insights into data, not otherwise possible. A variety of examples of the benefits of modeling nonlinear relationships are presented throughout the book. Methods are covered using what are called fractional polynomials based on real-valued power transformations of primary predictor variables combined with model selection based on likelihood cross-validation. The book covers how to formulate and conduct such adaptive fractional polynomial modeling in the s...

Nonlinear modelling of polymer electrolyte membrane fuel cell stack using nonlinear cancellation technique

Energy Technology Data Exchange (ETDEWEB)

Barus, R. P. P., E-mail: rismawan.ppb@gmail.com [Engineering Physics, Faculty of Industrial Technology, Institut Teknologi Bandung, Jalan Ganesa 10 Bandung and Centre for Material and Technical Product, Jalan Sangkuriang No. 14 Bandung (Indonesia); Tjokronegoro, H. A.; Leksono, E. [Engineering Physics, Faculty of Industrial Technology, Institut Teknologi Bandung, Jalan Ganesa 10 Bandung (Indonesia); Ismunandar [Chemistry Study, Faculty of Mathematics and Science, Institut Teknologi Bandung, Jalan Ganesa 10 Bandung (Indonesia)

2014-09-25

Fuel cells are promising new energy conversion devices that are friendly to the environment. A set of control systems are required in order to operate a fuel cell based power plant system optimally. For the purpose of control system design, an accurate fuel cell stack model in describing the dynamics of the real system is needed. Currently, linear model are widely used for fuel cell stack control purposes, but it has limitations in narrow operation range. While nonlinear models lead to nonlinear control implemnetation whos more complex and hard computing. In this research, nonlinear cancellation technique will be used to transform a nonlinear model into a linear form while maintaining the nonlinear characteristics. The transformation is done by replacing the input of the original model by a certain virtual input that has nonlinear relationship with the original input. Then the equality of the two models is tested by running a series of simulation. Input variation of H2, O2 and H2O as well as disturbance input I (current load) are studied by simulation. The error of comparison between the proposed model and the original nonlinear model are less than 1 %. Thus we can conclude that nonlinear cancellation technique can be used to represent fuel cell nonlinear model in a simple linear form while maintaining the nonlinear characteristics and therefore retain the wide operation range.

Nonlinear modelling of polymer electrolyte membrane fuel cell stack using nonlinear cancellation technique

International Nuclear Information System (INIS)

Barus, R. P. P.; Tjokronegoro, H. A.; Leksono, E.; Ismunandar

2014-01-01

Fuel cells are promising new energy conversion devices that are friendly to the environment. A set of control systems are required in order to operate a fuel cell based power plant system optimally. For the purpose of control system design, an accurate fuel cell stack model in describing the dynamics of the real system is needed. Currently, linear model are widely used for fuel cell stack control purposes, but it has limitations in narrow operation range. While nonlinear models lead to nonlinear control implemnetation whos more complex and hard computing. In this research, nonlinear cancellation technique will be used to transform a nonlinear model into a linear form while maintaining the nonlinear characteristics. The transformation is done by replacing the input of the original model by a certain virtual input that has nonlinear relationship with the original input. Then the equality of the two models is tested by running a series of simulation. Input variation of H2, O2 and H2O as well as disturbance input I (current load) are studied by simulation. The error of comparison between the proposed model and the original nonlinear model are less than 1 %. Thus we can conclude that nonlinear cancellation technique can be used to represent fuel cell nonlinear model in a simple linear form while maintaining the nonlinear characteristics and therefore retain the wide operation range

Autonomic dysfunction in Hodgkin and non-Hodgkin lymphoma. A paraneoplastic syndrome?

Directory of Open Access Journals (Sweden)

Franca Bilora

2010-11-01

Full Text Available We wanted to determine whether autonomic dysfunction in patients with lymphoma is related to chemotherapy or represent a paraneoplastic syndrome. 40 patients with current or cured Hodgkin or non-Hodgkin lymphoma and 40 healthy controls, matched for age, gender, hypertension and diabetes mellitus underwent autonomic evaluation (Deep Breath, Valsalva Maneuver, Hand Grip, Lying to Standing, Tilt Test. Current patients also suffering from diabetes or hypertension, or still on chemotherapy revealed autonomic changes, while cured or healthy subjects did not. Autonomic dysfunction in lymphoma is a transient manifestation of a paraneoplastic syndrome.

General Information about Adult Hodgkin Lymphoma

Science.gov (United States)

... Lymphocyte-rich classical Hodgkin lymphoma. Age, gender, and Epstein-Barr infection can affect the risk of adult Hodgkin lymphoma. Anything that increases your risk of getting a disease is called a risk factor . Having a risk ...

Comparison of Langevin and Markov channel noise models for neuronal signal generation.

Science.gov (United States)

Sengupta, B; Laughlin, S B; Niven, J E

2010-01-01

The stochastic opening and closing of voltage-gated ion channels produce noise in neurons. The effect of this noise on the neuronal performance has been modeled using either an approximate or Langevin model based on stochastic differential equations or an exact model based on a Markov process model of channel gating. Yet whether the Langevin model accurately reproduces the channel noise produced by the Markov model remains unclear. Here we present a comparison between Langevin and Markov models of channel noise in neurons using single compartment Hodgkin-Huxley models containing either Na+ and K+, or only K+ voltage-gated ion channels. The performance of the Langevin and Markov models was quantified over a range of stimulus statistics, membrane areas, and channel numbers. We find that in comparison to the Markov model, the Langevin model underestimates the noise contributed by voltage-gated ion channels, overestimating information rates for both spiking and nonspiking membranes. Even with increasing numbers of channels, the difference between the two models persists. This suggests that the Langevin model may not be suitable for accurately simulating channel noise in neurons, even in simulations with large numbers of ion channels.

Generalized Nonlinear Yule Models

Science.gov (United States)

Lansky, Petr; Polito, Federico; Sacerdote, Laura

2016-11-01

With the aim of considering models related to random graphs growth exhibiting persistent memory, we propose a fractional nonlinear modification of the classical Yule model often studied in the context of macroevolution. Here the model is analyzed and interpreted in the framework of the development of networks such as the World Wide Web. Nonlinearity is introduced by replacing the linear birth process governing the growth of the in-links of each specific webpage with a fractional nonlinear birth process with completely general birth rates. Among the main results we derive the explicit distribution of the number of in-links of a webpage chosen uniformly at random recognizing the contribution to the asymptotics and the finite time correction. The mean value of the latter distribution is also calculated explicitly in the most general case. Furthermore, in order to show the usefulness of our results, we particularize them in the case of specific birth rates giving rise to a saturating behaviour, a property that is often observed in nature. The further specialization to the non-fractional case allows us to extend the Yule model accounting for a nonlinear growth.

Study Under AC Stimulation on Excitement Properties of Weighted Small-World Biological Neural Networks with Side-Restrain Mechanism

International Nuclear Information System (INIS)

Yuan Wujie; Luo Xiaoshu; Jiang Pinqun

2007-01-01

In this paper, we propose a new model of weighted small-world biological neural networks based on biophysical Hodgkin-Huxley neurons with side-restrain mechanism. Then we study excitement properties of the model under alternating current (AC) stimulation. The study shows that the excitement properties in the networks are preferably consistent with the behavior properties of a brain nervous system under different AC stimuli, such as refractory period and the brain neural excitement response induced by different intensities of noise and coupling. The results of the study have reference worthiness for the brain nerve electrophysiology and epistemological science.

A Parsimonious Model of the Rabbit Action Potential Elucidates the Minimal Physiological Requirements for Alternans and Spiral Wave Breakup.

Science.gov (United States)

Gray, Richard A; Pathmanathan, Pras

2016-10-01

Elucidating the underlying mechanisms of fatal cardiac arrhythmias requires a tight integration of electrophysiological experiments, models, and theory. Existing models of transmembrane action potential (AP) are complex (resulting in over parameterization) and varied (leading to dissimilar predictions). Thus, simpler models are needed to elucidate the "minimal physiological requirements" to reproduce significant observable phenomena using as few parameters as possible. Moreover, models have been derived from experimental studies from a variety of species under a range of environmental conditions (for example, all existing rabbit AP models incorporate a formulation of the rapid sodium current, INa, based on 30 year old data from chick embryo cell aggregates). Here we develop a simple "parsimonious" rabbit AP model that is mathematically identifiable (i.e., not over parameterized) by combining a novel Hodgkin-Huxley formulation of INa with a phenomenological model of repolarization similar to the voltage dependent, time-independent rectifying outward potassium current (IK). The model was calibrated using the following experimental data sets measured from the same species (rabbit) under physiological conditions: dynamic current-voltage (I-V) relationships during the AP upstroke; rapid recovery of AP excitability during the relative refractory period; and steady-state INa inactivation via voltage clamp. Simulations reproduced several important "emergent" phenomena including cellular alternans at rates > 250 bpm as observed in rabbit myocytes, reentrant spiral waves as observed on the surface of the rabbit heart, and spiral wave breakup. Model variants were studied which elucidated the minimal requirements for alternans and spiral wave break up, namely the kinetics of INa inactivation and the non-linear rectification of IK.The simplicity of the model, and the fact that its parameters have physiological meaning, make it ideal for engendering generalizable mechanistic

Nonlinear behaviour of cantilevered carbon nanotube resonators based on a new nonlinear electrostatic load model

Science.gov (United States)

Farokhi, Hamed; Païdoussis, Michael P.; Misra, Arun K.

2018-04-01

The present study examines the nonlinear behaviour of a cantilevered carbon nanotube (CNT) resonator and its mass detection sensitivity, employing a new nonlinear electrostatic load model. More specifically, a 3D finite element model is developed in order to obtain the electrostatic load distribution on cantilevered CNT resonators. A new nonlinear electrostatic load model is then proposed accounting for the end effects due to finite length. Additionally, a new nonlinear size-dependent continuum model is developed for the cantilevered CNT resonator, employing the modified couple stress theory (to account for size-effects) together with the Kelvin-Voigt model (to account for nonlinear damping); the size-dependent model takes into account all sources of nonlinearity, i.e. geometrical and inertial nonlinearities as well as nonlinearities associated with damping, small-scale, and electrostatic load. The nonlinear equation of motion of the cantilevered CNT resonator is obtained based on the new models developed for the CNT resonator and the electrostatic load. The Galerkin method is then applied to the nonlinear equation of motion, resulting in a set of nonlinear ordinary differential equations, consisting of geometrical, inertial, electrical, damping, and size-dependent nonlinear terms. This high-dimensional nonlinear discretized model is solved numerically utilizing the pseudo-arclength continuation technique. The nonlinear static and dynamic responses of the system are examined for various cases, investigating the effect of DC and AC voltages, length-scale parameter, nonlinear damping, and electrostatic load. Moreover, the mass detection sensitivity of the system is examined for possible application of the CNT resonator as a nanosensor.

Nonlinear models for autoregressive conditional heteroskedasticity

DEFF Research Database (Denmark)

Teräsvirta, Timo

This paper contains a brief survey of nonlinear models of autore- gressive conditional heteroskedasticity. The models in question are parametric nonlinear extensions of the original model by Engle (1982). After presenting the individual models, linearity testing and parameter estimation are discu...

[Predictive value of Hodgkin's lymphoma tumor burden in present].

Science.gov (United States)

Kulyova, S A; Karitsky, A P

2014-01-01

Today approximately 70% of patients with Hodgkin lymphoma can be cured with the combined-modality therapy. Tumor burden, the importance of which was demonstrated 15 years ago for the first time, is a powerful prognostic factor. Data of literature of representations on predictive value of Hodgkin's lymphoma tumor burden are shown in the article. The difficult immunological relations between tumor cells and reactive ones lead to development of the main symptoms. Nevertheless, the collective sign of tumor burden shows the greatest influence on survival and on probability of resistance, which relative risk can be predicted on this variable and treatment program. Patients with bulky disease need escalated therapy with high-dose chemotherapy. Integration into predictive models of the variable will change an expected contribution of clinical and laboratory parameters in the regression analyses constructed on patients with Hodgkin's lymphoma. Today the role of diagnostic functional methods, in particular a positron emission tomography, for metabolic active measurement is conducted which allows excluding a reactive component.

Electrosensory Midbrain Neurons Display Feature Invariant Responses to Natural Communication Stimuli.

Directory of Open Access Journals (Sweden)

Tristan Aumentado-Armstrong

2015-10-01

Full Text Available Neurons that respond selectively but in an invariant manner to a given feature of natural stimuli have been observed across species and systems. Such responses emerge in higher brain areas, thereby suggesting that they occur by integrating afferent input. However, the mechanisms by which such integration occurs are poorly understood. Here we show that midbrain electrosensory neurons can respond selectively and in an invariant manner to heterogeneity in behaviorally relevant stimulus waveforms. Such invariant responses were not seen in hindbrain electrosensory neurons providing afferent input to these midbrain neurons, suggesting that response invariance results from nonlinear integration of such input. To test this hypothesis, we built a model based on the Hodgkin-Huxley formalism that received realistic afferent input. We found that multiple combinations of parameter values could give rise to invariant responses matching those seen experimentally. Our model thus shows that there are multiple solutions towards achieving invariant responses and reveals how subthreshold membrane conductances help promote robust and invariant firing in response to heterogeneous stimulus waveforms associated with behaviorally relevant stimuli. We discuss the implications of our findings for the electrosensory and other systems.

Electrosensory Midbrain Neurons Display Feature Invariant Responses to Natural Communication Stimuli.

Science.gov (United States)

Aumentado-Armstrong, Tristan; Metzen, Michael G; Sproule, Michael K J; Chacron, Maurice J

2015-10-01

Neurons that respond selectively but in an invariant manner to a given feature of natural stimuli have been observed across species and systems. Such responses emerge in higher brain areas, thereby suggesting that they occur by integrating afferent input. However, the mechanisms by which such integration occurs are poorly understood. Here we show that midbrain electrosensory neurons can respond selectively and in an invariant manner to heterogeneity in behaviorally relevant stimulus waveforms. Such invariant responses were not seen in hindbrain electrosensory neurons providing afferent input to these midbrain neurons, suggesting that response invariance results from nonlinear integration of such input. To test this hypothesis, we built a model based on the Hodgkin-Huxley formalism that received realistic afferent input. We found that multiple combinations of parameter values could give rise to invariant responses matching those seen experimentally. Our model thus shows that there are multiple solutions towards achieving invariant responses and reveals how subthreshold membrane conductances help promote robust and invariant firing in response to heterogeneous stimulus waveforms associated with behaviorally relevant stimuli. We discuss the implications of our findings for the electrosensory and other systems.

Human Brain Networks: Spiking Neuron Models, Multistability, Synchronization, Thermodynamics, Maximum Entropy Production, and Anesthetic Cascade Mechanisms

Directory of Open Access Journals (Sweden)

Wassim M. Haddad

2014-07-01

Full Text Available Advances in neuroscience have been closely linked to mathematical modeling beginning with the integrate-and-fire model of Lapicque and proceeding through the modeling of the action potential by Hodgkin and Huxley to the current era. The fundamental building block of the central nervous system, the neuron, may be thought of as a dynamic element that is “excitable”, and can generate a pulse or spike whenever the electrochemical potential across the cell membrane of the neuron exceeds a threshold. A key application of nonlinear dynamical systems theory to the neurosciences is to study phenomena of the central nervous system that exhibit nearly discontinuous transitions between macroscopic states. A very challenging and clinically important problem exhibiting this phenomenon is the induction of general anesthesia. In any specific patient, the transition from consciousness to unconsciousness as the concentration of anesthetic drugs increases is very sharp, resembling a thermodynamic phase transition. This paper focuses on multistability theory for continuous and discontinuous dynamical systems having a set of multiple isolated equilibria and/or a continuum of equilibria. Multistability is the property whereby the solutions of a dynamical system can alternate between two or more mutually exclusive Lyapunov stable and convergent equilibrium states under asymptotically slowly changing inputs or system parameters. In this paper, we extend the theory of multistability to continuous, discontinuous, and stochastic nonlinear dynamical systems. In particular, Lyapunov-based tests for multistability and synchronization of dynamical systems with continuously differentiable and absolutely continuous flows are established. The results are then applied to excitatory and inhibitory biological neuronal networks to explain the underlying mechanism of action for anesthesia and consciousness from a multistable dynamical system perspective, thereby providing a

Hodgkin's disease and age

DEFF Research Database (Denmark)

Specht, L.; Nissen, N.I.

1989-01-01

506 unselected, previously untreated patients with Hodgkin's disease were treated at the Finsen Institute between 1969 and 1983. The prognostic significance of age, sex, stage, systemic symptoms, histologic subtype, number of involved nodal regions, total tumour burden (peripheral + intrathoracic...... modality, stage, and total tumour burden, whereas age had no prognostic significance. With regard to death from Hodgkin's disease only age and total tumour burden had independent significance. The significance of age would seem to stem from the fact that some older patients could not be given adequate...

Hodgkin's Lymphoma

Science.gov (United States)

... People who have had illnesses caused by the Epstein-Barr virus, such as infectious mononucleosis, are more likely to develop Hodgkin's lymphoma than are people who haven't had Epstein-Barr infections. By Mayo Clinic Staff . Mayo Clinic Footer ...

Mathematical modeling and applications in nonlinear dynamics

CERN Document Server

Merdan, Hüseyin

2016-01-01

The book covers nonlinear physical problems and mathematical modeling, including molecular biology, genetics, neurosciences, artificial intelligence with classical problems in mechanics and astronomy and physics. The chapters present nonlinear mathematical modeling in life science and physics through nonlinear differential equations, nonlinear discrete equations and hybrid equations. Such modeling can be effectively applied to the wide spectrum of nonlinear physical problems, including the KAM (Kolmogorov-Arnold-Moser (KAM)) theory, singular differential equations, impulsive dichotomous linear systems, analytical bifurcation trees of periodic motions, and almost or pseudo- almost periodic solutions in nonlinear dynamical systems. Provides methods for mathematical models with switching, thresholds, and impulses, each of particular importance for discontinuous processes Includes qualitative analysis of behaviors on Tumor-Immune Systems and methods of analysis for DNA, neural networks and epidemiology Introduces...

From spiking neuron models to linear-nonlinear models.

Science.gov (United States)

Ostojic, Srdjan; Brunel, Nicolas

2011-01-20

Neurons transform time-varying inputs into action potentials emitted stochastically at a time dependent rate. The mapping from current input to output firing rate is often represented with the help of phenomenological models such as the linear-nonlinear (LN) cascade, in which the output firing rate is estimated by applying to the input successively a linear temporal filter and a static non-linear transformation. These simplified models leave out the biophysical details of action potential generation. It is not a priori clear to which extent the input-output mapping of biophysically more realistic, spiking neuron models can be reduced to a simple linear-nonlinear cascade. Here we investigate this question for the leaky integrate-and-fire (LIF), exponential integrate-and-fire (EIF) and conductance-based Wang-Buzsáki models in presence of background synaptic activity. We exploit available analytic results for these models to determine the corresponding linear filter and static non-linearity in a parameter-free form. We show that the obtained functions are identical to the linear filter and static non-linearity determined using standard reverse correlation analysis. We then quantitatively compare the output of the corresponding linear-nonlinear cascade with numerical simulations of spiking neurons, systematically varying the parameters of input signal and background noise. We find that the LN cascade provides accurate estimates of the firing rates of spiking neurons in most of parameter space. For the EIF and Wang-Buzsáki models, we show that the LN cascade can be reduced to a firing rate model, the timescale of which we determine analytically. Finally we introduce an adaptive timescale rate model in which the timescale of the linear filter depends on the instantaneous firing rate. This model leads to highly accurate estimates of instantaneous firing rates.

Intussuscepção em linfoma Não-Hodgkin Intussuception in Non-Hodgkin's lymphoma

Directory of Open Access Journals (Sweden)

Alessandra O. Ehrhardt

2003-06-01

Full Text Available Intussusception in adults is a rare condition and it can occur as a gastric complication from non-Hodgkin's lymphoma. Such complications can be difficult to diagnose because of ill-defined symptoms. Methods of imaging such as abdominal X-rays, ultrasonography, tomography and colonoscopy are useful for its diagnosis. Here a female patient with non-Hodgkin's lymphoma that evolved to intussusception of bowels, the regression of which was achieved by clinical and chemotherapeutic treatment without surgical intervention.

Second cancers after treatment for Hodgkin's disease: A review

International Nuclear Information System (INIS)

Boivin, J.F.; Hutchison, G.B.

1984-01-01

The authors review several reports of series of patients with Hodgkin's disease among whom second primary cancers have been diagnosed after radiotherapy or chemotherapy or both for Hodgkin's disease. An analysis of these reports suggests that (a) chemotherapy is a strong risk factor for leukemia, and (b) in the absence of chemotherapy, leukemia shows little or no increased incidence over ''spontaneous'' rates. Seven drugs have been identified as being frequently used in treatment of Hodgkin's disease (nitrogen mustard, cyclophosphamide, chlorambucil, procarbazine, vinglastine, vincristine, and prednisone). A large proportion of the patients receiving chemotherapy for Hodgkin's disease are exposed to several drugs and quantitative estimates of the independent leukemogenic effects of these drugs have not yet been obtained. Most of the person-years' experience accrued in the published studies occurred in the first decade after treatment for Hodgkin's disease. Follow-up over longer intervals of time will be necessary before solid tumor risk after therapy for Hodgkin's disease can be evaluated

Differences in Virological and Immunological Risk Factors for Non-Hodgkin and Hodgkin Lymphoma

DEFF Research Database (Denmark)

Shepherd, Leah; Ryom, Lene; Law, Matthew

2018-01-01

Background: Non-Hodgkin lymphoma (NHL) and Hodgkin lymphoma (HL) are increased in populations with immune dysfunction, including people living with HIV; however, there is little evidence for to what degree immunological and virological factors differently affect NHL and HL risk. Methods: Data from...... the Data Collection on Adverse events of Anti-HIV Drugs Study cohort were analyzed to identify independent risk factors for NHL and HL using hazard ratios (HRs), focusing on current and cumulative area under the curve (AUC) measures of immunological and virological status. Variables with different...

MRI assessment of bone marrow involvement in Hodgkin disease and non-Hodgkin lymphoma

International Nuclear Information System (INIS)

Tesoro Tess, J.D.; Balzarini, L.; Ceglia, E.; Petrillo, R.; Musumeci, R.

1990-01-01

In order to evaluate the possible role of MRI in detecting lymphomatous marrow involvement, a MRI examination was performed in newly diagnosed patients with Hodgkin's disease (HD) and nonHodgkin lymphoma (NHL). From this the authors concluded that MRI should not be used as a replacement for bone marrow biopsies in HD and NHL, but rather as a complementary tool utilizing the panoramic view offered by MRI which permit to disclose focal areas of bone involvement different from the sacrum, thus not valuable with routine biopsies. (author). 4 refs.; 1 tab

Finite element model for nonlinear shells of revolution

International Nuclear Information System (INIS)

Cook, W.A.

1979-01-01

Nuclear material shipping containers have shells of revolution as basic structural components. Analytically modeling the response of these containers to severe accident impact conditions requires a nonlinear shell-of-revolution model that accounts for both geometric and material nonlinearities. Existing models are limited to large displacements, small rotations, and nonlinear materials. The paper presents a finite element model for a nonlinear shell of revolution that will account for large displacements, large strains, large rotations, and nonlinear materials

Characteristics of Hodgkin's lymphoma after infectious mononucleosis

DEFF Research Database (Denmark)

Hjalgrim, Henrik; Askling, Johan; Rostgaard, Klaus

2003-01-01

BACKGROUND: Infectious mononucleosis-related Epstein-Barr virus (EBV) infection has been associated with an increased risk of Hodgkin's lymphoma in young adults. Whether the association is causal remains unclear. METHODS: We compared the incidence rates of Hodgkin's lymphoma in two population...

Linfoma no-Hodgkin del sistema nervioso central

OpenAIRE

Iglesias Rozas, José Rafael, 1942-

2000-01-01

Diecisiete imágenes de un linfoma no-Hodgkin del sistema nervioso central en una paciente de 66 años. Seventeen pictures of a non-Hodgkin lymphoma of the central nervous system in a 66-year-old female patient.

PET imaging in pediatric Hodgkin's lymphoma

International Nuclear Information System (INIS)

Hudson, M.M.; Krasin, M.J.; Kaste, S.C.

2004-01-01

Advances in diagnostic imaging technology, especially functional imaging modalities like positron emission tomography (PET), have significantly influenced the staging and treatment approaches used for pediatric Hodgkin's lymphoma. Today, the majority of children and adolescents diagnosed with Hodgkin's lymphoma will be cured following treatment with noncross-resistant combination chemotherapy alone or in combination with low-dose, involved-field radiation. This success produced a greater appreciation of long-term complications related to radiation, chemotherapy, and surgical staging that prompted significant changes in staging and treatment protocols for children and adolescents with Hodgkin's lymphoma. Contemporary treatment for pediatric Hodgkin's lymphoma uses a risk-adapted approach that reduces the number of combination chemotherapy cycles and radiation treatment fields and doses for patients with localized favorable disease presentation. Advances in diagnostic imaging technology have played a critical role in the development of these risk-adapted treatment regimens. The introduction of computed tomography (CT) provided an accurate and non-invasive modality to define nodal involvement below the diaphragm that motivated the change from surgical to clinical staging. The introduction of functional imaging modalities, like positron emission tomography (PET) scanning, provided the means to correlate tumor activity with anatomic features generated by CT and modify treatment based on tumor response. For centers with access to this modality, PET imaging plays an important role in staging, evaluating tumor response, planning radiation treatment fields, and monitoring after completion of therapy for pediatric Hodgkin's lymphoma. (orig.)

Superspace formulation of new nonlinear sigma models

International Nuclear Information System (INIS)

Gates, S.J. Jr.

1983-07-01

The superspace formulation of two classes of supersymmetric nonlinear σ-models are presented. Two alternative N=1 superspace formulations are given for the d=2 supersymmetric nonlinear σ-models with Killing vector potentials: (a) formulation uses an active central charge and, (b) formulation uses a spurion superfield without inducing a classical breakdown of supersymmetry. The N=2 vector multiplet is used to construct a new class of d=4 nonlinear σ-models which when reduced to d=2 possess N=4 supersymmetry. Implications of these two classes of nonlinear σ-models for N>=4 superfield supergravity are discussed. (author)

Targeted immunotherapy in Hodgkin lymphoma

DEFF Research Database (Denmark)

Hutchings, Martin

2015-01-01

In this issue of Blood, Rothe et al introduce a new principle of targeted Hodgkin lymphoma (HL) immunotherapy in their report from a phase 1 study of the bispecific anti-CD30/CD16A antibody construct AFM13.......In this issue of Blood, Rothe et al introduce a new principle of targeted Hodgkin lymphoma (HL) immunotherapy in their report from a phase 1 study of the bispecific anti-CD30/CD16A antibody construct AFM13....

Forecasting with nonlinear time series models

DEFF Research Database (Denmark)

Kock, Anders Bredahl; Teräsvirta, Timo

In this paper, nonlinear models are restricted to mean nonlinear parametric models. Several such models popular in time series econo- metrics are presented and some of their properties discussed. This in- cludes two models based on universal approximators: the Kolmogorov- Gabor polynomial model...... applied to economic fore- casting problems, is briefly highlighted. A number of large published studies comparing macroeconomic forecasts obtained using different time series models are discussed, and the paper also contains a small simulation study comparing recursive and direct forecasts in a partic...... and two versions of a simple artificial neural network model. Techniques for generating multi-period forecasts from nonlinear models recursively are considered, and the direct (non-recursive) method for this purpose is mentioned as well. Forecasting with com- plex dynamic systems, albeit less frequently...

Fuzzy model-based servo and model following control for nonlinear systems.

Science.gov (United States)

Ohtake, Hiroshi; Tanaka, Kazuo; Wang, Hua O

2009-12-01

This correspondence presents servo and nonlinear model following controls for a class of nonlinear systems using the Takagi-Sugeno fuzzy model-based control approach. First, the construction method of the augmented fuzzy system for continuous-time nonlinear systems is proposed by differentiating the original nonlinear system. Second, the dynamic fuzzy servo controller and the dynamic fuzzy model following controller, which can make outputs of the nonlinear system converge to target points and to outputs of the reference system, respectively, are introduced. Finally, the servo and model following controller design conditions are given in terms of linear matrix inequalities. Design examples illustrate the utility of this approach.

Identification of nonlinear anelastic models

International Nuclear Information System (INIS)

Draganescu, G E; Bereteu, L; Ercuta, A

2008-01-01

A useful nonlinear identification technique applied to the anelastic and rheologic models is presented in this paper. First introduced by Feldman, the method is based on the Hilbert transform, and is currently used for identification of the nonlinear vibrations

Relation between nonlinear models and gauge ambiguities

International Nuclear Information System (INIS)

Balachandran, A.P.; Ramachandran, R.; Rupertsberger, H.; Skagerstam, B.S.

1980-01-01

We show that the solutions of a class of nonlinear models also generate gauge ambiguities in the vacuum sector of Yang-Mills theories. Our results extend known connections between gauge ambiguities and certain nonlinear sigma-models, and clarify the underlying group theory. For many nonlinear models, we also give a simple, intrinsic parametrization of physical fields (which have values in a homogeneous space of a group). (orig.)

Mucormicosis yeyunal en paciente con linfoma de Hodgkin Jejunal mucormycosis in a patient with Hodgkin's lymphoma

Directory of Open Access Journals (Sweden)

B. Madrigal

2008-08-01

Full Text Available Comunicamos un caso de mucormicosis intestinal en un hombre de 46 años de edad, diagnosticado de enfermedad de Hodgkin clásica, estadio IV-B. Durante la primera fase de la quimioterapia, sufrió una hemorragia digestiva masiva secundaria a una úlcera yeyunal por zigomicosis tipo mucor, diagnosticada por biopsia endoscópica. El paciente fue tratado con antifúngicos y resección quirúrgica del intestino afectado. En la cirugía, se apreció una doble perforación yeyunal cubierta. El estudio anatomopatológico de la pieza confirmó el diagnóstico previo. Tras un año de seguimiento, el paciente está recuperado y su linfoma de Hodgkin en remisión completa. Tras una extensa revisión de la literatura, según nuestro conocimiento, este es el segundo caso publicado en la literatura de mucormicosis intestinal en un paciente con linfoma de Hodgkin.We report a case of intestinal mucormycosis in a 46-year-old male diagnosed with classical Hodgkin's disease, IV-B stage. During the first phase of chemotherapy he had a massive digestive bleeding event secondary to a jejunal ulcer, and zygomicosis mucor-type was diagnosed by endoscopic biopsy. The patient was treated with antifungal drugs and surgical resection of the intestine involved. At surgery a double covered perforation of the jejunum was seen. Pathological examination confirmed the previous diagnosis. After one year of follow-up the patient is doing well, and his lymphoma is on remission. To our best knowledge this is the second case of intestinal mucormycosis in a patient with Hodgkin's lymphoma reported in the medical literature.

Physics constrained nonlinear regression models for time series

International Nuclear Information System (INIS)

Majda, Andrew J; Harlim, John

2013-01-01

A central issue in contemporary science is the development of data driven statistical nonlinear dynamical models for time series of partial observations of nature or a complex physical model. It has been established recently that ad hoc quadratic multi-level regression (MLR) models can have finite-time blow up of statistical solutions and/or pathological behaviour of their invariant measure. Here a new class of physics constrained multi-level quadratic regression models are introduced, analysed and applied to build reduced stochastic models from data of nonlinear systems. These models have the advantages of incorporating memory effects in time as well as the nonlinear noise from energy conserving nonlinear interactions. The mathematical guidelines for the performance and behaviour of these physics constrained MLR models as well as filtering algorithms for their implementation are developed here. Data driven applications of these new multi-level nonlinear regression models are developed for test models involving a nonlinear oscillator with memory effects and the difficult test case of the truncated Burgers–Hopf model. These new physics constrained quadratic MLR models are proposed here as process models for Bayesian estimation through Markov chain Monte Carlo algorithms of low frequency behaviour in complex physical data. (paper)

Non-linear finite element modeling

DEFF Research Database (Denmark)

Mikkelsen, Lars Pilgaard

The note is written for courses in "Non-linear finite element method". The note has been used by the author teaching non-linear finite element modeling at Civil Engineering at Aalborg University, Computational Mechanics at Aalborg University Esbjerg, Structural Engineering at the University...

Pneumonitis following infradiaphragmatic irradiation in Hodgkin's disease. Pneumonitis nach infradiaphragmaler Bestrahlung bei Morbus Hodgkin

Energy Technology Data Exchange (ETDEWEB)

Zierhut, D.; Flentje, M. (Radiologische Klinik, Heidelberg Univ. (Germany)); Kalle, A. von (Medizinische Poliklinik, Heidelberg Univ. (Germany)); Moeller, P. (Pathologisches Inst., Heidelberg Univ. (Germany))

1992-12-01

A case is reported on radiation pneumonitis in the left costodiaphragmatic sinus 6 weeks following combined chemo- and radiotherapy of Hodgkin's disease. Thoracotomy was performed in order to exclude a pulmonal relapse of Hodgkin's disease. Thereby the diagnosis of radiation pneumonitis was histologically proven. The development of pneumonitis after irradiation of the spleen may occur and has to be considered in the differential diagnosis of pulmonal affections. (orig.).

Correlations and Non-Linear Probability Models

DEFF Research Database (Denmark)

Breen, Richard; Holm, Anders; Karlson, Kristian Bernt

2014-01-01

the dependent variable of the latent variable model and its predictor variables. We show how this correlation can be derived from the parameters of non-linear probability models, develop tests for the statistical significance of the derived correlation, and illustrate its usefulness in two applications. Under......Although the parameters of logit and probit and other non-linear probability models are often explained and interpreted in relation to the regression coefficients of an underlying linear latent variable model, we argue that they may also be usefully interpreted in terms of the correlations between...... certain circumstances, which we explain, the derived correlation provides a way of overcoming the problems inherent in cross-sample comparisons of the parameters of non-linear probability models....

Non-linear Loudspeaker Unit Modelling

DEFF Research Database (Denmark)

Pedersen, Bo Rohde; Agerkvist, Finn T.

2008-01-01

Simulations of a 6½-inch loudspeaker unit are performed and compared with a displacement measurement. The non-linear loudspeaker model is based on the major nonlinear functions and expanded with time-varying suspension behaviour and flux modulation. The results are presented with FFT plots of thr...... frequencies and different displacement levels. The model errors are discussed and analysed including a test with loudspeaker unit where the diaphragm is removed....

Role of routine imaging in detecting recurrent lymphoma; a review of 258 patients with relapsed aggressive non-Hodgkin and Hodgkin lymphoma

DEFF Research Database (Denmark)

El-Galaly, Tarec Christoffer; Mylam, Karen Juul; Bøgsted, Martin

2014-01-01

After first-line therapy, patients with Hodgkin and aggressive non-Hodgkin lymphomas are followed closely for early signs of relapse. The current follow-up practice with frequent use of surveillance imaging is highly controversial and warrants a critical evaluation. Therefore a retrospective...... multicenter study of relapsed Hodgkin and aggressive non-Hodgkin lymphomas (nodal T-cell and diffuse large B-cell lymphomas) was conducted. All included patients had been diagnosed during the period 2002-2011 and relapsed after achieving complete remission on first-line therapy. Characteristics and outcome...... of imaging-detected relapses were compared to other relapses. A total of 258 patients with recurrent lymphoma were included in the study. Relapse investigations were initiated outside preplanned visits in 52% of the patients. Relapse detection could be attributed to patient-reported symptoms alone...

Discrete peritoneal and pericardial implants of non-Hodgkin lymphoma

International Nuclear Information System (INIS)

Eckel, C.G.; Davis, M.; Mettler, F.A. Jr.; Rosenberg, R.

1987-01-01

Peritoneal spread of non-Hodgkin lymphoma is rare: fewer than three percent of persons afflicted with this disease develop peritoneal spread. Pericardial involvement by non-Hodgkin lymphoma is equally rare. We report an instance of peritoneal and pericardial spread in a patient with non-Hodgkin lymphoma that was detected only by CT scan. The peritoneal lesions were not visible by ultrasound examination. A pertinent review of the literature is presented. (author)

Dynamic behaviors in directed networks

International Nuclear Information System (INIS)

Park, Sung Min; Kim, Beom Jun

2006-01-01

Motivated by the abundance of directed synaptic couplings in a real biological neuronal network, we investigate the synchronization behavior of the Hodgkin-Huxley model in a directed network. We start from the standard model of the Watts-Strogatz undirected network and then change undirected edges to directed arcs with a given probability, still preserving the connectivity of the network. A generalized clustering coefficient for directed networks is defined and used to investigate the interplay between the synchronization behavior and underlying structural properties of directed networks. We observe that the directedness of complex networks plays an important role in emerging dynamical behaviors, which is also confirmed by a numerical study of the sociological game theoretic voter model on directed networks

Autoimmunity and susceptibility to Hodgkin lymphoma: a population-based case-control study in Scandinavia.

Science.gov (United States)

Landgren, Ola; Engels, Eric A; Pfeiffer, Ruth M; Gridley, Gloria; Mellemkjaer, Lene; Olsen, Jørgen H; Kerstann, Kimberly F; Wheeler, William; Hemminki, Kari; Linet, Martha S; Goldin, Lynn R

2006-09-20

Personal history of autoimmune diseases is consistently associated with increased risk of non-Hodgkin lymphoma. In contrast, there are limited data on risk of Hodgkin lymphoma following autoimmune diseases and almost no data addressing whether there is a familial association between the conditions. Using population-based linked registry data from Sweden and Denmark, 32 separate autoimmune and related conditions were identified from hospital diagnoses in 7476 case subjects with Hodgkin lymphoma, 18,573 matched control subjects, and more than 86,000 first-degree relatives of case and control subjects. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) as measures of relative risks for each condition using logistic regression and also applied multivariable hierarchical regression models. All P values are two-sided. We found statistically significantly increased risks of Hodgkin lymphoma associated with personal histories of several autoimmune conditions, including rheumatoid arthritis (OR = 2.7, 95% CI = 1.9 to 4.0), systemic lupus erythematosus (OR = 5.8, 95% CI = 2.2 to 15.1), sarcoidosis (OR = 14.1, 95% CI = 5.4 to 36.8), and immune thrombocytopenic purpura (OR = infinity, P = .002). A statistically significant increase in risk of Hodgkin lymphoma was associated with family histories of sarcoidosis (OR = 1.8, 95% CI = 1.01 to 3.1) and ulcerative colitis (OR = 1.6, 95% CI = 1.02 to 2.6). Personal or family history of certain autoimmune conditions was strongly associated with increased risk of Hodgkin lymphoma. The association between both personal and family histories of sarcoidosis and a statistically significantly increased risk of Hodgkin lymphoma suggests shared susceptibility for these conditions.

Modeling of Volatility with Non-linear Time Series Model

OpenAIRE

Kim Song Yon; Kim Mun Chol

2013-01-01

In this paper, non-linear time series models are used to describe volatility in financial time series data. To describe volatility, two of the non-linear time series are combined into form TAR (Threshold Auto-Regressive Model) with AARCH (Asymmetric Auto-Regressive Conditional Heteroskedasticity) error term and its parameter estimation is studied.

N2A: a computational tool for modeling from neurons to algorithms

Directory of Open Access Journals (Sweden)

Fredrick eRothganger

2014-01-01

Full Text Available The exponential increase in available neural data has combined with the exponential growth in computing (Moore’s law to create new opportunities to understand neural systems at large scale and high detail. The ability to produce large and sophisticated simulations has introduced unique challenges to neuroscientists. Computational models in neuroscience are increasingly broad efforts, often involving the collaboration of experts in different domains. Furthermore, the size and detail of models have grown to levels for which understanding the implications of variability and assumptions is no longer trivial. Here, we introduce the model design platform N2A which aims to facilitate the design and validation of biologically realistic models. N2A uses a hierarchical representation of neural information to enable the integration of models from different users. N2A streamlines computational validation of a model by natively implementing standard tools in sensitivity analysis and uncertainty quantification. The part-relationship representation allows both network-level analysis and dynamical simulations. We will demonstrate how N2A can be used in a range of examples, including a simple Hodgkin-Huxley cable model, basic parameter sensitivity of an 80/20 network, and the expression of the structural plasticity of a growing dendrite and stem cell proliferation and differentiation.

Alisertib in Combination With Vorinostat in Treating Patients With Relapsed or Recurrent Hodgkin Lymphoma, B-Cell Non-Hodgkin Lymphoma, or Peripheral T-Cell Lymphoma

Science.gov (United States)

2018-04-10

Adult B Acute Lymphoblastic Leukemia; Adult T Acute Lymphoblastic Leukemia; Anaplastic Large Cell Lymphoma; Angioimmunoblastic T-Cell Lymphoma; Chronic Lymphocytic Leukemia; Extranodal Marginal Zone Lymphoma of Mucosa-Associated Lymphoid Tissue; Hepatosplenic T-Cell Lymphoma; Intraocular Lymphoma; Lymphomatous Involvement of Non-Cutaneous Extranodal Site; Mature T-Cell and NK-Cell Non-Hodgkin Lymphoma; Nodal Marginal Zone Lymphoma; Primary Cutaneous B-Cell Non-Hodgkin Lymphoma; Recurrent Adult Acute Lymphoblastic Leukemia; Recurrent Adult Burkitt Lymphoma; Recurrent Adult Grade III Lymphomatoid Granulomatosis; Recurrent Adult Hodgkin Lymphoma; Recurrent Adult Immunoblastic Lymphoma; Recurrent Adult Lymphoblastic Lymphoma; Recurrent Adult T-Cell Leukemia/Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Grade 3 Follicular Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Mycosis Fungoides and Sezary Syndrome; Recurrent Non-Hodgkin Lymphoma; Recurrent Primary Cutaneous T-Cell Non-Hodgkin Lymphoma; Recurrent Small Lymphocytic Lymphoma; Refractory Chronic Lymphocytic Leukemia; Refractory Hairy Cell Leukemia; Small Intestinal Lymphoma; Splenic Marginal Zone Lymphoma; T-Cell Large Granular Lymphocyte Leukemia; Testicular Lymphoma; Waldenstrom Macroglobulinemia

Comparing coefficients of nested nonlinear probability models

DEFF Research Database (Denmark)

Kohler, Ulrich; Karlson, Kristian Bernt; Holm, Anders

2011-01-01

In a series of recent articles, Karlson, Holm and Breen have developed a method for comparing the estimated coeffcients of two nested nonlinear probability models. This article describes this method and the user-written program khb that implements the method. The KHB-method is a general decomposi......In a series of recent articles, Karlson, Holm and Breen have developed a method for comparing the estimated coeffcients of two nested nonlinear probability models. This article describes this method and the user-written program khb that implements the method. The KHB-method is a general...... decomposition method that is unaffected by the rescaling or attenuation bias that arise in cross-model comparisons in nonlinear models. It recovers the degree to which a control variable, Z, mediates or explains the relationship between X and a latent outcome variable, Y*, underlying the nonlinear probability...

Hodgkin's disease and age

DEFF Research Database (Denmark)

Specht, L; Nissen, N I

1989-01-01

506 unselected, previously untreated patients with Hodgkin's disease were treated at the Finsen Institute between 1969 and 1983. The prognostic significance of age, sex, stage, systemic symptoms, histologic subtype, number of involved nodal regions, total tumour burden (peripheral + intrathoracic...... nodal tumour burden, intraabdominal nodal tumour burden, and number of involved extranodal sites), pretreatment ESR, lymphocytopenia, and treatment modality were examined in multivariate analyses. The only factors of independent prognostic significance for disease-free survival proved to be treatment...... modality, stage, and total tumour burden, whereas age had no prognostic significance. With regard to death from Hodgkin's disease only age and total tumour burden had independent significance. The significance of age would seem to stem from the fact that some older patients could not be given adequate...

Spiking Regularity and Coherence in Complex Hodgkin–Huxley Neuron Networks

International Nuclear Information System (INIS)

Zhi-Qiang, Sun; Ping, Xie; Wei, Li; Peng-Ye, Wang

2010-01-01

We study the effects of the strength of coupling between neurons on the spiking regularity and coherence in a complex network with randomly connected Hodgkin–Huxley neurons driven by colored noise. It is found that for the given topology realization and colored noise correlation time, there exists an optimal strength of coupling, at which the spiking regularity of the network reaches the best level. Moreover, when the temporal regularity reaches the best level, the spatial coherence of the system has already increased to a relatively high level. In addition, for the given number of neurons and noise correlation time, the values of average regularity and spatial coherence at the optimal strength of coupling are nearly independent of the topology realization. Furthermore, there exists an optimal value of colored noise correlation time at which the spiking regularity can reach its best level. These results may be helpful for understanding of the real neuron world. (cross-disciplinary physics and related areas of science and technology)

Doença de Hodgkin

Directory of Open Access Journals (Sweden)

Marina Pereira

1999-05-01

Full Text Available RESUMO: Os autores descrevem um caso de doença de Hodgkin, do subtipo esclerose nodular, numa mulher de 24 anos de idade. A forma de apresentação clínica, pouco habitual, é constituída por uma massa na regão esternal e parede anterior do hemitórax esquerdo, a qual adquire grande volume ao fim de 2 anos e meio de evolução natural da doença. Esta é tratada com quimioterapia (MOPP e radioterapia adjuvante, sofrendo uma reeressão total das suas manifestações clínicas.REV PORT PNEUMOL 1999; V (3: 349-355 ABSTRACT: A case of a 24 years old woman with Hodgkin’s disease, nodular sclerosis subtype, is reported. The disease present with an anterior chest wall mass, an unusual clinical presentation form. The patient receive MOPP chemotherapy and adjuvant radio-therapy with complete resolution of her clinical manifestations.REV PORT PNEUMOL 1999; V (3: 349-355 Palavras-chave: Doença de Hodgkin, Massa da parede torácica anterior, Forma de apresentação clinica, Key-words: Hodgkin’s disease, Anterior chest wall mass, Clinical presentation form

Nonlinear Control of Heartbeat Models

Directory of Open Access Journals (Sweden)

Witt Thanom

2011-02-01

Full Text Available This paper presents a novel application of nonlinear control theory to heartbeat models. Existing heartbeat models are investigated and modified by incorporating the control input as a pacemaker to provide the control channel. A nonlinear feedback linearization technique is applied to force the output of the systems to generate artificial electrocardiogram (ECG signal using discrete data as the reference inputs. The synthetic ECG may serve as a flexible signal source to assess the effectiveness of a diagnostic ECG signal-processing device.

Mediastinal Hodgkin lymphomas in computertomography: exact CT-based volume assessment and approximations with simple geometric models; Mediastinale Hodgkin-Lymphone in der Computertomographie. Vergleich von exakter CT-gestuetzter Volumetrie und Volumenabschaetzung mit Hilfe einfacher geometrischer Modelle

Energy Technology Data Exchange (ETDEWEB)

Battmann, A. [Marburg Univ. (Germany). Abt. fuer Strahlendiagnostik; Dieckmann, K.; Resch, A.; Poetter, R. [Allgemeines Krankenhaus, Wien (Austria). Universitaetsklinik Strahlentherapie und Strahlenbiologie; Battmann, A. [Giessen Univ. (Germany). Zentrum fuer Pathologie

2001-03-01

Background: The importance of the size of the primary tumor in lymphomas and its size after treatment is still uncertain. Assuming a prognostic relevance, an assessment of tumor volume before and after induction of chemotherapy has been performed in the pediatric Hodgkin's disease study (HD-90). Since an exact CT-scan-based volumetric tumor assessment is time-consuming and in some centers not possible, the tumor volume is often estimated based on simple geometric approximations. Aim of this study was the development of an easy to apply and nearly exact model of volume estimation compared to CT-scan-based tumor volume measurements. Material and Methods: thirty computed tomographies (CT) of mediastinal Hodgkin lymphomas of children aged 5 to 16 years have been examined. The CT scans were digitalized using a CCD camera combined with a frame grabber. Applying the Global Lab image software, the true tumor volume was determined excluding local organs, which did not belong to the lymphoma. Subsequently, volumes were assessed using simple geometric models (block, ellipsoid, octaeder) by using the maximum diameters of the tumor. The differences between the volume of the geometric models and the true volume, based on the CT scan evaluation, were compared. Results: the maximum diameters of a tumor can be used to calculate its volume based on simple geometric models. The model 'block' overestimates the volume by 89 to 268%. The model 'ellipsoid' overestimates the volume on average by 29%. The model 'octaeder' underestimates the volume on average by 18%. A division of the block volume by 2.3 approximated the geometric closest to the true volume: the average volume was overestimated by 2% in tumors with a volume larger than 20 ml. No model was sufficient to approximate tumors with a volume of less than 20 ml. Conclusions: for the estimation of tumor volumes in mediastinal Hodgkin lumphomas exceeding 20 ml, the formula 'block /2.3&apos

Hodgkin's disease part 1: pathology, staging, and management of early stage disease

International Nuclear Information System (INIS)

Mauch, Peter; Yahalom, Joachim

1995-01-01

Over the past 25 years there have been dramatic improvements in our understanding of the epidemiology, biology, natural history, and treatment of Hodgkins disease. Hodgkin's disease is one of the few cancers where both chemotherapy and radiation therapy have provided dramatic improvements in cure of this once uniformly fatal disease. Part 1 of the refresher course on Hodgkin's disease will include a review of: 1) New Findings in epidemiology, immunohistochemistry and molecular biology of the Reed-Sternberg cell including association with Epstein-Barr virus; 2) Review of pathology including discussions of NS 1 vs NS2, and nodular LP subclassifications; 3) Recommendations for staging including the role of staging laparotomy in Hodgkin's disease; 4) Standard techniques for commonly used radiation therapy fields for Hodgkin's disease and 5) Treatment of early stage Hodgkin's disease including an overview on recent and current clinical trials

Comparison of squamous cell carcinoma with non-Hodgkin's lymphoma of tonsillar region

International Nuclear Information System (INIS)

Tsukiyama, Iwao; Yamashita, Kohsuke; Kajiura, Yuuichi; Ogino, Takashi; Akine, Yasuyuki; Egawa, Sunao; Ono, Isamu

1987-01-01

A total of 98 patients with malignant tumors of the tonsil (Squamous cell carcinoma, 34 patients, Non-Hodgkin's lymphoma, 64 patients) werw treated with radiation therapy between 1962 and 1979 at the National Cancer Center Hospital. All were staged by the TNM system, using UICC Classification 1978. With regard to stage distribution, Stage III is most frequent (47.1 %) in squamous cell carcinoma, Stage IV is most frequent (48.4 %) in Non-Hodgkin's lymphoma. Much more advanced cases were included in Non-Hodgkin's lymphoma. Five year survival rate for patients with squamous cell carcinoma and Non-Hodgkin's lymphoma were 49 % and 62 %, respectively. 50 % survival months with squamous cell carcinoma and Non-Hodgkin's lymphoma were 58.7 months and 195.5 months, respectively. Better prognosis was observed in Non-Hodgkin's lymphoma than squamous cell cacinoma. (author)

Nonlinear structural mechanics theory, dynamical phenomena and modeling

CERN Document Server

Lacarbonara, Walter

2013-01-01

Nonlinear Structural Mechanics: Theory, Dynamical Phenomena and Modeling offers a concise, coherent presentation of the theoretical framework of nonlinear structural mechanics, computational methods, applications, parametric investigations of nonlinear phenomena and their mechanical interpretation towards design. The theoretical and computational tools that enable the formulation, solution, and interpretation of nonlinear structures are presented in a systematic fashion so as to gradually attain an increasing level of complexity of structural behaviors, under the prevailing assumptions on the geometry of deformation, the constitutive aspects and the loading scenarios. Readers will find a treatment of the foundations of nonlinear structural mechanics towards advanced reduced models, unified with modern computational tools in the framework of the prominent nonlinear structural dynamic phenomena while tackling both the mathematical and applied sciences. Nonlinear Structural Mechanics: Theory, Dynamical Phenomena...

Explicit Nonlinear Model Predictive Control Theory and Applications

CERN Document Server

Grancharova, Alexandra

2012-01-01

Nonlinear Model Predictive Control (NMPC) has become the accepted methodology to solve complex control problems related to process industries. The main motivation behind explicit NMPC is that an explicit state feedback law avoids the need for executing a numerical optimization algorithm in real time. The benefits of an explicit solution, in addition to the efficient on-line computations, include also verifiability of the implementation and the possibility to design embedded control systems with low software and hardware complexity. This book considers the multi-parametric Nonlinear Programming (mp-NLP) approaches to explicit approximate NMPC of constrained nonlinear systems, developed by the authors, as well as their applications to various NMPC problem formulations and several case studies. The following types of nonlinear systems are considered, resulting in different NMPC problem formulations: Ø  Nonlinear systems described by first-principles models and nonlinear systems described by black-box models; �...

Rheumatic manifestations at presentation of Hodgkin's disease and non-Hodgkin's malignant lymphoma. A national survey of one hundred forty-six patients

International Nuclear Information System (INIS)

Gaudin, P.; Rozand, Y.; Fauconnier, J.; Phelip, X.

1995-01-01

The authors report the findings of a national survey conducted at the request for the French Society for Rheumatology to list the rheumatic manifestations that can be inaugural in Hodgkin's disease on non-Hodgkin's malignant lymphoma. This was an exploratory, retrospective, descriptive study of 146 patients from 22 rheumatology departments. A number of clinical features (young male, nocturnal sweats, generalized pruritus, protracted fever, central or peripheral lymphadenopathy) and laboratory test abnormalities (evidence of severe inflammation) considerably increased the likelihood of Hodgkin's disease rather than malignant lymphoma. The diagnosis of bony involvement requires multidisciplinary studies of tumor specimens. (authors). 4 figs., 7 tabs., 71 refs

Analysis of nonlinear systems using ARMA [autoregressive moving average] models

International Nuclear Information System (INIS)

Hunter, N.F. Jr.

1990-01-01

While many vibration systems exhibit primarily linear behavior, a significant percentage of the systems encountered in vibration and model testing are mildly to severely nonlinear. Analysis methods for such nonlinear systems are not yet well developed and the response of such systems is not accurately predicted by linear models. Nonlinear ARMA (autoregressive moving average) models are one method for the analysis and response prediction of nonlinear vibratory systems. In this paper we review the background of linear and nonlinear ARMA models, and illustrate the application of these models to nonlinear vibration systems. We conclude by summarizing the advantages and disadvantages of ARMA models and emphasizing prospects for future development. 14 refs., 11 figs

Nonlinear State Space Modeling and System Identification for Electrohydraulic Control

Directory of Open Access Journals (Sweden)

Jun Yan

2013-01-01

Full Text Available The paper deals with nonlinear modeling and identification of an electrohydraulic control system for improving its tracking performance. We build the nonlinear state space model for analyzing the highly nonlinear system and then develop a Hammerstein-Wiener (H-W model which consists of a static input nonlinear block with two-segment polynomial nonlinearities, a linear time-invariant dynamic block, and a static output nonlinear block with single polynomial nonlinearity to describe it. We simplify the H-W model into a linear-in-parameters structure by using the key term separation principle and then use a modified recursive least square method with iterative estimation of internal variables to identify all the unknown parameters simultaneously. It is found that the proposed H-W model approximates the actual system better than the independent Hammerstein, Wiener, and ARX models. The prediction error of the H-W model is about 13%, 54%, and 58% less than the Hammerstein, Wiener, and ARX models, respectively.

Pneumonitis following infradiaphragmatic irradiation in Hodgkin's disease

International Nuclear Information System (INIS)

Zierhut, D.; Flentje, M.; Kalle, A. von; Moeller, P.

1992-01-01

A case is reported on radiation pneumonitis in the left costodiaphragmatic sinus 6 weeks following combined chemo- and radiotherapy of Hodgkin's disease. Thoracotomy was performed in order to exclude a pulmonal relapse of Hodgkin's disease. Thereby the diagnosis of radiation pneumonitis was histologically proven. The development of pneumonitis after irradiation of the spleen may occur and has to be considered in the differential diagnosis of pulmonal affections. (orig.) [de

Hodgkin's lymphoma mimicking necrotizing pneumonia: case report

Energy Technology Data Exchange (ETDEWEB)

Park, Eun Ah; Lee, Hyun Ju; Im, Jung GI; Goo, Jin Mo; Lim, Kun Young; Lee, Chang Hyun [College of Medicine, Seoul National Univ., Seoul (Korea, Republic of)

2004-11-01

This study describes a case of pulmonary Hodgkin's lymphoma of the nodular sclerosing type presenting as a large cavitary mass with air-fluid levels. We also conduct a review of the previous articles on pulmonary Hodgkin's lymphoma.

When long-range zero-lag synchronization is feasible in cortical networks

Directory of Open Access Journals (Sweden)

Atthaphon eViriyopase

2012-07-01

Full Text Available Many studies have reported long-range synchronization of neuronal activity between brain areas, in particular in the gamma-band with frequencies in the range of 40-80 Hz. Several studies have reported synchrony with zero phase lag, which is remarkable considering the synaptic and conduction delays inherent in the connections between distant brain areas. This result has led to many speculations about the possible functional role of zero-lag synchrony, e.g., for neuronal communication in attention, memory and feature binding. However, recent studies using recordings of single-unit activity and local field potentials report that neuronal synchronization occurs with non-zero phase lags. This raises the questions whether zero-lag synchrony can occur in the brain and, if so, under which conditions.We used analytical methods and computer simulations to investigate which connectivity between neuronal populations allows or prohibits zero-lag synchrony. We did so for a model where two oscillators interact via a relay oscillator. Analytical results and computer simulations were obtained for both type I Mirollo-Strogatz neurons and type II Hodgkin-Huxley neurons. We have investigated the dynamics of the model for various types of synaptic coupling and importantly considered the potential impact of Spike-Timing Dependent Plasticity (STDP and its learning window. We confirm previous results that zero-lag synchrony can be achieved in this configuration. This is much easier to achieve with Hodgkin-Huxley neurons, which have a biphasic phase response curve, than for type I neurons. STDP facilitates zero-lag synchrony as it adjusts the synaptic strengths such that zero-lag synchrony is feasible for a much larger range of parameters than without STDP.

Metallothionein as a useful marker in Hodgkin lymphoma subclassification

DEFF Research Database (Denmark)

Penkowa, Milena; Sørensen, Brit Ladegaard; Nielsen, Signe Lidou

2009-01-01

Metallothionein (MT) expression is considered to be a prognostic factor that promotes tumor resistance to apoptosis. In non-Hodgkin lymphomas, MT is differentially expressed and constitutes a risk factor. We have characterised MT in lymph nodes of Hodgkin lymphoma (HL) [patients with nodular...

Increasing inhibitory input increases neuronal firing rate: why and when? Diffusion process cases

Energy Technology Data Exchange (ETDEWEB)

Feng Jianfeng [COGS, Sussex University (United Kingdom)]. E-mail: jf218@cam.ac.uk; Wei Gang [Department of Mathematics, Hong Kong Baptist University, Hong Kong (China)]. E-mail gwei@math.hkbu.edu.hk

2001-09-21

Increasing inhibitory input to single neuronal models, such as the FitzHugh-Nagumo model and the Hodgkin-Huxley model, can sometimes increase their firing rates, a phenomenon which we term inhibition-boosted firing (IBF). Here we consider neuronal models with diffusion approximation inputs, i.e. they share the identical first- and second-order statistics of the corresponding Poisson process inputs. Using the integrate-and-fire model and the IF-FHN model, we explore theoretically how and when IBF can happen. For both models, it is shown that there is a critical input frequency at which the efferent firing rate is identical when the neuron receives purely excitatory inputs or exactly balanced inhibitory and excitatory inputs. When the input frequency is lower than the critical frequency, IBF occurs. (author)

Modelled temperature-dependent excitability behaviour of a generalised human peripheral sensory nerve fibre.

Science.gov (United States)

Smit, Jacoba E; Hanekom, Tania; Hanekom, Johan J

2009-08-01

The objective of this study was to determine if a recently developed human Ranvier node model, which is based on a modified version of the Hodgkin-Huxley model, could predict the excitability behaviour in human peripheral sensory nerve fibres with diameters ranging from 5.0 to 15.0 microm. The Ranvier node model was extended to include a persistent sodium current and was incorporated into a generalised single cable nerve fibre model. Parameter temperature dependence was included. All calculations were performed in Matlab. Sensory nerve fibre excitability behaviour characteristics predicted by the new nerve fibre model at different temperatures and fibre diameters compared well with measured data. Absolute refractory periods deviated from measured data, while relative refractory periods were similar to measured data. Conduction velocities showed both fibre diameter and temperature dependence and were underestimated in fibres thinner than 12.5 microm. Calculated strength-duration time constants ranged from 128.5 to 183.0 micros at 37 degrees C over the studied nerve fibre diameter range, with chronaxie times about 30% shorter than strength-duration time constants. Chronaxie times exhibited temperature dependence, with values overestimated by a factor 5 at temperatures lower than body temperature. Possible explanations include the deviated absolute refractory period trend and inclusion of a nodal strangulation relationship.

Bilateral breast cancer after cured Hodgkin's disease

International Nuclear Information System (INIS)

Anderson, N.; Lokich, J.

1990-01-01

Three patients developed bilateral breast cancer at 10 to 24 years after mantle irradiation for locally or systemically advanced Hodgkin's disease (HD). Four of the six cancers in the three patients were detected only by mammography. Pathologically, five of the cancers were intraductal carcinomas (four with an invasive component) with one being a lobular carcinoma. Five of the six lesions were Stage I pathologically without evidence of axillary nodal involvement. It is recommended that female patients with Hodgkin's disease who have received mantle irradiation as part of the therapy for their Hodgkin's disease and who are observed for 10 or more years after completion of mantle irradiation be considered at risk for the development of breast cancer. Such patients should be monitored appropriately by routine bilateral mammograms to increase the early detection of early stage lesions

NONLINEAR PLANT PIECEWISE-CONTINUOUS MODEL MATRIX PARAMETERS ESTIMATION

Directory of Open Access Journals (Sweden)

Roman L. Leibov

2017-09-01

Full Text Available This paper presents a nonlinear plant piecewise-continuous model matrix parameters estimation technique using nonlinear model time responses and random search method. One of piecewise-continuous model application areas is defined. The results of proposed approach application for aircraft turbofan engine piecewisecontinuous model formation are presented

Genetically Modified Peripheral Blood Stem Cell Transplant in Treating Patients With HIV-Associated Non-Hodgkin or Hodgkin Lymphoma

Science.gov (United States)

2015-05-06

Adult Nasal Type Extranodal NK/T-cell Lymphoma; AIDS-related Diffuse Large Cell Lymphoma; AIDS-related Diffuse Mixed Cell Lymphoma; AIDS-related Diffuse Small Cleaved Cell Lymphoma; AIDS-related Immunoblastic Large Cell Lymphoma; AIDS-related Lymphoblastic Lymphoma; AIDS-related Peripheral/Systemic Lymphoma; AIDS-related Small Noncleaved Cell Lymphoma; Anaplastic Large Cell Lymphoma; Angioimmunoblastic T-cell Lymphoma; Cutaneous B-cell Non-Hodgkin Lymphoma; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Hepatosplenic T-cell Lymphoma; HIV-associated Hodgkin Lymphoma; Intraocular Lymphoma; Nodal Marginal Zone B-cell Lymphoma; Noncutaneous Extranodal Lymphoma; Peripheral T-cell Lymphoma; Recurrent Adult Burkitt Lymphoma; Recurrent Adult Diffuse Large Cell Lymphoma; Recurrent Adult Diffuse Mixed Cell Lymphoma; Recurrent Adult Diffuse Small Cleaved Cell Lymphoma; Recurrent Adult Grade III Lymphomatoid Granulomatosis; Recurrent Adult Hodgkin Lymphoma; Recurrent Adult Immunoblastic Large Cell Lymphoma; Recurrent Adult Lymphoblastic Lymphoma; Recurrent Adult T-cell Leukemia/Lymphoma; Recurrent Cutaneous T-cell Non-Hodgkin Lymphoma; Recurrent Grade 1 Follicular Lymphoma; Recurrent Grade 2 Follicular Lymphoma; Recurrent Grade 3 Follicular Lymphoma; Recurrent Mantle Cell Lymphoma; Recurrent Marginal Zone Lymphoma; Recurrent Mycosis Fungoides/Sezary Syndrome; Recurrent Small Lymphocytic Lymphoma; Refractory Hairy Cell Leukemia; Small Intestine Lymphoma; Splenic Marginal Zone Lymphoma; Stage I AIDS-related Lymphoma; Stage II AIDS-related Lymphoma; Stage III AIDS-related Lymphoma; Stage IV AIDS-related Lymphoma; T-cell Large Granular Lymphocyte Leukemia; Testicular Lymphoma; Waldenström Macroglobulinemia

Study of the nonlinear imperfect software debugging model

International Nuclear Information System (INIS)

Wang, Jinyong; Wu, Zhibo

2016-01-01

In recent years there has been a dramatic proliferation of research on imperfect software debugging phenomena. Software debugging is a complex process and is affected by a variety of factors, including the environment, resources, personnel skills, and personnel psychologies. Therefore, the simple assumption that debugging is perfect is inconsistent with the actual software debugging process, wherein a new fault can be introduced when removing a fault. Furthermore, the fault introduction process is nonlinear, and the cumulative number of nonlinearly introduced faults increases over time. Thus, this paper proposes a nonlinear, NHPP imperfect software debugging model in consideration of the fact that fault introduction is a nonlinear process. The fitting and predictive power of the NHPP-based proposed model are validated through related experiments. Experimental results show that this model displays better fitting and predicting performance than the traditional NHPP-based perfect and imperfect software debugging models. S-confidence bounds are set to analyze the performance of the proposed model. This study also examines and discusses optimal software release-time policy comprehensively. In addition, this research on the nonlinear process of fault introduction is significant given the recent surge of studies on software-intensive products, such as cloud computing and big data. - Highlights: • Fault introduction is a nonlinear changing process during the debugging phase. • The assumption that the process of fault introduction is nonlinear is credible. • Our proposed model can better fit and accurately predict software failure behavior. • Research on fault introduction case is significant to software-intensive products.

Dorothy Reed and Hodgkin's disease: a reflection after a century

International Nuclear Information System (INIS)

Zwitter, Matjaz; Cohen, Joel R.; Barrett, Ann; Robinton, Elizabeth D.

2002-01-01

It has now been 100 years since Dorothy Reed, at the age of 28, wrote her paper on Hodgkin's disease. Her biography reveals the difficult lives of women entering the hitherto male-dominated field of medicine, let alone medical research. Her historic paper on Hodgkin's disease is remarkable for its brilliant observations and concise scientific reasoning. Nevertheless, she was told that as a woman she could not hope for a career as an academic pathologist. After marriage to Charles Elwood Mendenhall, Professor of Physics at the University of Wisconsin and after giving birth to four children, the second part of her career began. Motivated by the loss of her firstborn, she began a study of infant mortality, an interest that lasted throughout her career. In 1926, Mendenhall undertook a survey comparing infant and maternal mortality rates in Denmark and the United States. This influential study concluded that American mortality rates were higher because of unnecessary interference in the natural process of childbirth and recommended the education of midwives follow the Danish model. In 1937, her efforts were rewarded when Madison, WI received recognition for having the lowest infant mortality of any city in the United States. Reading Reed's paper on Hodgkin's disease, we see that her observations go far beyond a description of a specific cell. Her presentation of macroscopic and microscopic features is remarkable for the distinction between 'young' and 'old' growths: Reed saw Hodgkin's disease as a process, rather than the spreading of a cancer. She was the first to note that those most commonly affected are boys or young adults, especially those whose general health before the disease had been excellent. She was also the first to note anergy to tuberculin. Dorothy Reed defined Hodgkin's disease in relation to tuberculosis, described its pathologic features, and offered comments on its pathogenesis, epidemiology, and immunology that still deserve to be discussed

Heterotic sigma models and non-linear strings

International Nuclear Information System (INIS)

Hull, C.M.

1986-01-01

The two-dimensional supersymmetric non-linear sigma models are examined with respect to the heterotic string. The paper was presented at the workshop on :Supersymmetry and its applications', Cambridge, United Kingdom, 1985. The non-linear sigma model with Wess-Zumino-type term, the coupling of the fermionic superfields to the sigma model, super-conformal invariance, and the supersymmetric string, are all discussed. (U.K.)

Controlling Chaos in Neuron Based on Lasalle Invariance Principle

International Nuclear Information System (INIS)

Wei Duqu; Qin Yinghua

2011-01-01

A new control law is proposed to asymptotically stabilize the chaotic neuron system based on LaSalle invariant principle. The control technique does not require analytical knowledge of the system dynamics and operates without an explicit knowledge of the desired steady-state position. The well-known modified Hodgkin-Huxley (MHH) and Hindmarsh-Rose (HR) model neurons are taken as examples to verify the implementation of our method. Simulation results show the proposed control law is effective. The outcome of this study is significant since it is helpful to understand the learning process of a human brain towards the information processing, memory and abnormal discharge of the brain neurons. (general)

Comparison of time stepping schemes on the cable equation

Directory of Open Access Journals (Sweden)

Chuan Li

2010-09-01

Full Text Available Electrical propagation in excitable tissue, such as nerve fibers and heart muscle, is described by a parabolic PDE for the transmembrane voltage $V(x,t$, known as the cable equation, $$ frac{1}{r_a}frac{partial^2V}{partial x^2} = C_mfrac{partial V}{partial t} + I_{m ion}(V,t + I_{m stim}(t $$ where $r_a$ and $C_m$ are the axial resistance and membrane capacitance. The source term $I_{m ion}$ represents the total ionic current across the membrane, governed by the Hodgkin-Huxley or other more complicated ionic models. $I_{m stim}(t$ is an applied stimulus current.

Loss of B cell identity correlates with loss of B cell-specific transcription factors in Hodgkin/Reed-Sternberg cells of classical Hodgkin lymphoma

DEFF Research Database (Denmark)

Hertel, Christina B; Zhou, Xiao-ge; Hamilton-Dutoit, Stephen J

2002-01-01

In classical Hodgkin lymphoma the malignant Hodgkin/Reed-Sternberg (HRS) cells characteristically constitute only a small minority of the tumour load. Their origin has been debated for decades, but on the basis of rearrangement and somatic hypermutations of their immunoglubulin (Ig) genes, HRS ce...

Non-Hodgkin lymphoma - children

Science.gov (United States)

... families share common experiences may help ease your stress. American Childhood Cancer Organization - www.acco.org Leukemia and ... Updated: January 27, 2016. Accessed June 3, 2016. American Society of Clinical ... Institute website. Childhood non-Hodgkin lymphoma treatment (PDQ) - health ...

Stomach cancer risk after treatment for hodgkin lymphoma

DEFF Research Database (Denmark)

Morton, Lindsay M; Dores, Graça M; Curtis, Rochelle E

2013-01-01

Treatment-related stomach cancer is an important cause of morbidity and mortality among the growing number of Hodgkin lymphoma (HL) survivors, but risks associated with specific HL treatments are unclear.......Treatment-related stomach cancer is an important cause of morbidity and mortality among the growing number of Hodgkin lymphoma (HL) survivors, but risks associated with specific HL treatments are unclear....

Female reproductive potential after treatment for Hodgkin's disease

International Nuclear Information System (INIS)

Horning, S.J.; Hoppe, R.T.; Kaplan, H.S.; Rosenberg, S.A.

1981-01-01

The probability of maintaining ovarian function, becoming pregnant, and delivering a normal child is important to young women anticipating successful therapy for Hodgkin's disease. In this study, reproductive function was retrospectively examined in 103 women 40 years old or younger who had undergone treatment for Hodgkin's disease with total-lymphoid irradiation (TLI) alone, combination chemotherapy, or combined TLI and chemotherapy. Infertility was directly related to gonadal exposure to therapy and to age at treatment. Twenty women became pregnant after receiving total-nodal irradiation or combination chemotherapy or both. No fetal wastage occurred, and no birth defects were seen in the 24 infants born to these women. Even after intensive treatment programs, women successfully treated for Hodgkin's disease have become pregnant and delivered phenotypically normal children

Apoptosis and radiosensitization of Hodgkin cells by proteasome inhibition

International Nuclear Information System (INIS)

Pajonk, Frank; Pajonk, Katja; McBride, William H.

2000-01-01

Purpose: Malignant cells from Hodgkin's disease have been reported to be defective in regulation of NF-κB activity. Ionizing radiation is known to activate NF-κB, and it has been suggested that this pathway may protect cells from apoptosis following exposure to radiation and other therapeutic agents. Defective NF-κB regulation in Hodgkin cells could therefore dictate the response of this disease to therapy, as well as be responsible for maintaining the malignant phenotype. The purpose of this study was to explore whether NF-κB activity could be modulated in Hodgkin cells and whether it determines the response of these cells to treatment with ionizing radiation and/or dexamethasone. Methods and Materials: Activation of NF-κB in cells is accomplished in large part by degradation of its inhibitor IκB through the 26s proteasome. HD-My-Z Hodgkin cells were treated with the proteasome inhibitor MG-132 or transduced with a dominant negative super-repressor IκBα. Clonogenic survival, apoptosis, proteasome activity, and NF-κB binding activity were monitored in response to ionizing radiation and/or dexamethasone treatment. Results: HD-My-Z Hodgkin cells had modest NF-κB levels but, unlike other cell types, did not decrease their level of constitutively active NF-κB in response to proteasome inhibition with MG-132. In contrast, transduction with a non-phosphorable IκBα construct abolished expression. MG-132 did, however, induce apoptosis in HD-My-Z cells and sensitized them to ionizing radiation. Dexamethasone treatment had no effect on NF-κB activity or clonogenic survival of Hodgkin cells, but protected them from irradiation. Conclusion: We conclude that inhibition of 26s proteasome activity can induce apoptosis in HD-My-Z Hodgkin cells and radiosensitize them, in spite of the fact that their constitutively active NF-κB levels are unaltered. The proteasome may be a promising new therapeutic target for intervention in this disease. In contrast, the use of

Nonlinear distortion in wireless systems modeling and simulation with Matlab

CERN Document Server

Gharaibeh, Khaled M

2011-01-01

This book covers the principles of modeling and simulation of nonlinear distortion in wireless communication systems with MATLAB simulations and techniques In this book, the author describes the principles of modeling and simulation of nonlinear distortion in single and multichannel wireless communication systems using both deterministic and stochastic signals. Models and simulation methods of nonlinear amplifiers explain in detail how to analyze and evaluate the performance of data communication links under nonlinear amplification. The book addresses the analysis of nonlinear systems

John Dewey em visita ao jardim de Huxley: uma discussão sobre a teoria da evolução e as concepções éticas

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José Cláudio Morelli Matos

2010-05-01

Full Text Available http://dx.doi.org/10.5007/1677-2954.2010v9n2p199 John Dewey escreve um de seus primeiros trabalhos sobre ética em resposta às idéias de Thomas Huxley. Huxley, em seu artigo “Evolution and Ethics” (1894, defendia uma oposição entre os processos naturais e os processos éticos. A ética, segundo ele, é contrária aos princípios que se observa na natureza. Para Dewey, por outro lado, não há dualismo entre as regularidades naturais e as regularidades sociais. Dewey pretende, em seu artigo homônimo ao de Huxley (1898, reconstruir o sentido de noções fundamentais ao pensamento evolutivo como “adaptado”, “luta pela vida” e “seleção natural”. Dando início a uma versão evolucionista da reflexão ética, Dewey supõe a continuidade entre o mundo natural e o mundo dos valores. Suas conclusões indicam não só uma abordagem evolutiva das questões éticas, mas a proposição de valores e condutas que estejam em conformidade com o crescimento e a mudança constante nos ambientes e nas funções adaptativas, tais como se observa no mundo natural.

Childhood Hodgkin Lymphoma Treatment (PDQ®)—Health Professional Version

Science.gov (United States)

In childhood Hodgkin lymphoma, current treatment uses risk-adapted, response-based paradigms to determine the length and intensity of treatment. Get detailed information about newly diagnosed and recurrent classical and nodular lymphocyte predominant Hodgkin lymphoma, including presentation, diagnosis and staging, prognosis, and treatment in this summary for clinicians.

Checkpoint inhibitors and radiation treatment in Hodgkin's lymphoma. New study concepts of the German Hodgkin Study Group

Energy Technology Data Exchange (ETDEWEB)

Baues, C.; Semrau, R.; Marnitz, S. [University of Cologne, Medical Faculty, Department of Radiooncology, Cologne (Germany); University of Cologne, German Hodgkin Study Group (GHSG), Cologne (Germany); Gaipl, U.S. [University Hospital Erlangen, Department of Radiooncology, Erlangen (Germany); Broeckelmann, P.J.; Engert, A. [University of Cologne, German Hodgkin Study Group (GHSG), Cologne (Germany); University of Cologne, Medical Faculty, Department of Internal Medicine I, Cologne (Germany); Rosenbrock, J. [University of Cologne, Medical Faculty, Department of Radiooncology, Cologne (Germany)

2017-02-15

Patients with classical Hodgkin's lymphoma (cHL) have a good prognosis even in advanced stages. However, combined chemo- and radiotherapy, as the standard of care, is also associated with treatment-related toxicities such as organ damage, secondary neoplasias, infertility, or fatigue and long-term fatigue. Many patients suffer from this burden although their cHL was cured. Therefore, the efficacy of immune checkpoint inhibitors like anti-PD1/PD-L1 antibodies in the treatment of solid cancers and also in HL offers new options. A remarkable and durable response rate with a favorable toxicity profile was observed in heavily pretreated cHL patients. Planning to perform prospective randomized clinical trials in the content of radio-immune treatment in patients with Hodgkin's lymphoma (HL), we transferred the results of preliminary clinical studies and basic research in clinical relevant study concepts. Based on these promising early phase trial data, the German Hodgkin Study Group (GHSG) will investigate innovative treatment regimens in upcoming phase II trials. The therapeutic efficacy and potential synergies of anti-PD1 antibodies in combination with chemo- or radiotherapy will be investigated in various settings of HL. (orig.) [German] Patienten mit einem klassischen Hodgkin-Lymphom (cHL) haben ueber alle Stadien hinweg eine gute Prognose. Allerdings treten unter der kombinierten Therapie mit Chemotherapie und Bestrahlung therapieabhaengige Toxizitaeten wie z. B. Organschaeden, Sekundaertumoren, Fatigue oder Langzeit-Fatigue auf. Viele Patienten leiden trotz einer Heilung an diesen Symptomen. Daher bietet die nachgewiesene Wirksamkeit der Anti-PD1/PD-L1-Antikoerper bei soliden Tumoren, aber auch beim HL neue Behandlungsoptionen. Bei intensiv vorbehandelten Patienten mit rezidiviertem cHL wurde bei guter Vertraeglichkeit eine hohe Ansprechrate mit z. T. langanhaltenden Remissionen beobachtet. Im Rahmen der Planung prospektiver randomisierter Studien im

Pyrogen release in vitro by lymphoid tissues from patients with Hodgkin's disease.

Science.gov (United States)

Bodel, P

1974-01-01

The mechanism of fever in patients with Hodgkin's disease was investigated by examining endogenous pyrogen production by blood, spleen, and lymph node cells incubated in vitro. Blood leucocytes from febrile or afebrile patients with Hodgkin's disease did not produce pyrogen spontaneously. Spleen cells, however, frequently released pyrogen during initial incubations, unlike spleen cells from patients with non-malignant diseases. Pyrogen production occurred from spleens without observed pathologic infiltrates of Hodgkin's disease. Lymph nodes involved with Hodgkin's disease produced pyrogen more frequently than did nodes involved with other diseases. Pyrogen production by tissue cells was prolonged, required protein synthesis, and in some cases was due to mononuclear cells; it did not correlate with fever in the patient. These studies demonstrate spontaneous production of endogenous pyrogen in vitro by lymphoid tissue cells from patients with Hodgkin's disease.

Modelling nonlinear viscoelastic behaviours of loudspeaker suspensions-like structures

Science.gov (United States)

Maillou, Balbine; Lotton, Pierrick; Novak, Antonin; Simon, Laurent

2018-03-01

Mechanical properties of an electrodynamic loudspeaker are mainly determined by its suspensions (surround and spider) that behave nonlinearly and typically exhibit frequency dependent viscoelastic properties such as creep effect. The paper aims at characterizing the mechanical behaviour of electrodynamic loudspeaker suspensions at low frequencies using nonlinear identification techniques developed in recent years. A Generalized Hammerstein based model can take into account both frequency dependency and nonlinear properties. As shown in the paper, the model generalizes existing nonlinear or viscoelastic models commonly used for loudspeaker modelling. It is further experimentally shown that a possible input-dependent law may play a key role in suspension characterization.

Avascular osteonecrosis in patients treated for Hodgkin`s disease

Energy Technology Data Exchange (ETDEWEB)

Enrici, R.M.; Donato, V.; Santoro, M. [La Sapienza Univ. of Rome, Inst. of Radiology, Chair of Radiation Oncology, Rome (Italy); Tombolini, V. [Univ of L`Aquila, Hospital S. Maria di Collemaggio, Dept. of Radiation Oncology, L`Aquila (Italy); Anselmo, A.P. [La Sapienza Univ. of Rome, Dept. of Human Biopathology, Haematology Section, Rome (Italy)

1998-09-01

The aim of this study is to assess the risk of avascular osteonecrosis (AVN) of the femoral head in patients treated for Hodgkin`s disease (HD), in relation to the type of treatment they have received. For this purpose, a cohort of 1391 patients treated for HD at University of Rome between 1972 and 1996 was divided into 2 groups according to their initial treatment. The first group contained 784 patients treated, at the onset of HD, either with chemotherapy (CT) containing steroids, combined in some cases with subdiaphragmatic radiotherapy (RT), or with subdiaphragmatic RT combined with CT without steroids. The second group was made up of 607 patients who had received, initially, supradiaphragmatic RT alone or supradiaphragmatic RT combined with CT without steroids. For the purpose of this study, only the 784 patients belonging to the first group were observed for the appearance of AVN, which occurred in 9 cases. The period of time which elapsed between the end of treatment and the radiological evidence of AVN ranged from 23 to 97 months, with an average of 35 months. Because the number of cases of AVN was so small, the pathogenesis of this complication could not be identified. (au) 55 refs.

Radiotherapy in the Hodgkin's disease

International Nuclear Information System (INIS)

Pinto, A.C.L.C.; Moura, J.E.F.M. de; Leite, M.T.T.; Santa Casa de Misericordia de Belo Horizonte

1983-01-01

An up-to-date summary of Hodgkin's disease is presented taking into account its natural history, dissemination patterns, history, staging and therapeutic sugestions, with special regard to radiotherapy. (Author) [pt

Risk of Hodgkin's disease and other cancers after infectious mononucleosis

DEFF Research Database (Denmark)

Hjalgrim, H; Askling, J; Sørensen, P

2000-01-01

BACKGROUND: Infectious mononucleosis, which is caused by the Epstein-Barr virus, has been associated with an increased risk for Hodgkin's disease. Little is known, however, about how infectious mononucleosis affects long-term risk of Hodgkin's disease, how this risk varies with age at infectious...... mononucleosis diagnosis, or how the risk for Hodgkin's disease varies in different age groups. In addition, the general cancer profile among patients who have had infectious mononucleosis has been sparsely studied. METHODS: Population-based cohorts of infectious mononucleosis patients in Denmark and Sweden were...... statistical tests including the trend tests were two-sided. RESULTS: A total of 1381 cancers were observed during 689 619 person-years of follow-up among 38 562 infectious mononucleosis patients (SIR = 1. 03; 95% confidence interval [CI] = 0.98-1.09). Apart from Hodgkin's disease (SIR = 2.55; 95% CI = 1...

Model reduction of nonlinear systems subject to input disturbances

KAUST Repository

Ndoye, Ibrahima

2017-07-10

The method of convex optimization is used as a tool for model reduction of a class of nonlinear systems in the presence of disturbances. It is shown that under some conditions the nonlinear disturbed system can be approximated by a reduced order nonlinear system with similar disturbance-output properties to the original plant. The proposed model reduction strategy preserves the nonlinearity and the input disturbance nature of the model. It guarantees a sufficiently small error between the outputs of the original and the reduced-order systems, and also maintains the properties of input-to-state stability. The matrices of the reduced order system are given in terms of a set of linear matrix inequalities (LMIs). The paper concludes with a demonstration of the proposed approach on model reduction of a nonlinear electronic circuit with additive disturbances.

Non-linear Growth Models in Mplus and SAS

Science.gov (United States)

Grimm, Kevin J.; Ram, Nilam

2013-01-01

Non-linear growth curves or growth curves that follow a specified non-linear function in time enable researchers to model complex developmental patterns with parameters that are easily interpretable. In this paper we describe how a variety of sigmoid curves can be fit using the Mplus structural modeling program and the non-linear mixed-effects modeling procedure NLMIXED in SAS. Using longitudinal achievement data collected as part of a study examining the effects of preschool instruction on academic gain we illustrate the procedures for fitting growth models of logistic, Gompertz, and Richards functions. Brief notes regarding the practical benefits, limitations, and choices faced in the fitting and estimation of such models are included. PMID:23882134

Dynamic mathematical modeling of IL13-induced signaling in Hodgkin and primary mediastinal B-cell lymphoma allows prediction of therapeutic targets.

Science.gov (United States)

Raia, Valentina; Schilling, Marcel; Böhm, Martin; Hahn, Bettina; Kowarsch, Andreas; Raue, Andreas; Sticht, Carsten; Bohl, Sebastian; Saile, Maria; Möller, Peter; Gretz, Norbert; Timmer, Jens; Theis, Fabian; Lehmann, Wolf-Dieter; Lichter, Peter; Klingmüller, Ursula

2011-02-01

Primary mediastinal B-cell lymphoma (PMBL) and classical Hodgkin lymphoma (cHL) share a frequent constitutive activation of JAK (Janus kinase)/STAT signaling pathway. Because of complex, nonlinear relations within the pathway, key dynamic properties remained to be identified to predict possible strategies for intervention. We report the development of dynamic pathway models based on quantitative data collected on signaling components of JAK/STAT pathway in two lymphoma-derived cell lines, MedB-1 and L1236, representative of PMBL and cHL, respectively. We show that the amounts of STAT5 and STAT6 are higher whereas those of SHP1 are lower in the two lymphoma cell lines than in normal B cells. Distinctively, L1236 cells harbor more JAK2 and less SHP1 molecules per cell than MedB-1 or control cells. In both lymphoma cell lines, we observe interleukin-13 (IL13)-induced activation of IL4 receptor α, JAK2, and STAT5, but not of STAT6. Genome-wide, 11 early and 16 sustained genes are upregulated by IL13 in both lymphoma cell lines. Specifically, the known STAT-inducible negative regulators CISH and SOCS3 are upregulated within 2 hours in MedB-1 but not in L1236 cells. On the basis of this detailed quantitative information, we established two mathematical models, MedB-1 and L1236 model, able to describe the respective experimental data. Most of the model parameters are identifiable and therefore the models are predictive. Sensitivity analysis of the model identifies six possible therapeutic targets able to reduce gene expression levels in L1236 cells and three in MedB-1. We experimentally confirm reduction in target gene expression in response to inhibition of STAT5 phosphorylation, thereby validating one of the predicted targets.

Model of anisotropic nonlinearity in self-defocusing photorefractive media.

Science.gov (United States)

Barsi, C; Fleischer, J W

2015-09-21

We develop a phenomenological model of anisotropy in self-defocusing photorefractive crystals. In addition to an independent term due to nonlinear susceptibility, we introduce a nonlinear, non-separable correction to the spectral diffraction operator. The model successfully describes the crossover between photovoltaic and photorefractive responses and the spatially dispersive shock wave behavior of a nonlinearly spreading Gaussian input beam. It should prove useful for characterizing internal charge dynamics in complex materials and for accurate image reconstruction through nonlinear media.

Non-Hodgkin lymphoma response evaluation with MRI texture classification

Directory of Open Access Journals (Sweden)

Heinonen Tomi T

2009-06-01

Full Text Available Abstract Background To show magnetic resonance imaging (MRI texture appearance change in non-Hodgkin lymphoma (NHL during treatment with response controlled by quantitative volume analysis. Methods A total of 19 patients having NHL with an evaluable lymphoma lesion were scanned at three imaging timepoints with 1.5T device during clinical treatment evaluation. Texture characteristics of images were analyzed and classified with MaZda application and statistical tests. Results NHL tissue MRI texture imaged before treatment and under chemotherapy was classified within several subgroups, showing best discrimination with 96% correct classification in non-linear discriminant analysis of T2-weighted images. Texture parameters of MRI data were successfully tested with statistical tests to assess the impact of the separability of the parameters in evaluating chemotherapy response in lymphoma tissue. Conclusion Texture characteristics of MRI data were classified successfully; this proved texture analysis to be potential quantitative means of representing lymphoma tissue changes during chemotherapy response monitoring.

Neuromorphic silicon neuron circuits

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Giacomo eIndiveri

2011-05-01

Full Text Available Hardware implementations of spiking neurons can be extremely useful for a large variety of applications, ranging from high-speed modeling of large-scale neural systems to real-time behaving systems, to bidirectional brain-machine interfaces. The specific circuit solutions used to implement silicon neurons depend on the application requirements. In this paper we describe the most common building blocks and techniques used to implement these circuits, and present an overview of a wide range of neuromorphic silicon neurons, which implement different computational models, ranging from biophysically realistic and conductance based Hodgkin-Huxley models to bi-dimensional generalized adaptive Integrate and Fire models. We compare the different design methodologies used for each silicon neuron design described, and demonstrate their features with experimental results, measured from a wide range of fabricated VLSI chips.

Nonlinear model predictive control theory and algorithms

CERN Document Server

Grüne, Lars

2017-01-01

This book offers readers a thorough and rigorous introduction to nonlinear model predictive control (NMPC) for discrete-time and sampled-data systems. NMPC schemes with and without stabilizing terminal constraints are detailed, and intuitive examples illustrate the performance of different NMPC variants. NMPC is interpreted as an approximation of infinite-horizon optimal control so that important properties like closed-loop stability, inverse optimality and suboptimality can be derived in a uniform manner. These results are complemented by discussions of feasibility and robustness. An introduction to nonlinear optimal control algorithms yields essential insights into how the nonlinear optimization routine—the core of any nonlinear model predictive controller—works. Accompanying software in MATLAB® and C++ (downloadable from extras.springer.com/), together with an explanatory appendix in the book itself, enables readers to perform computer experiments exploring the possibilities and limitations of NMPC. T...

Autologous hematopoietic stem cell transplantation in classical Hodgkin's lymphoma

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Afonso José Pereira Cortez

2011-02-01

Full Text Available BACKGROUND: Hodgkin's lymphoma has high rates of cure, but in 15% to 20% of general patients and between 35% and 40% of those in advanced stages, the disease will progress or will relapse after initial treatment. For this group, hematopoietic stem cell transplantation is considered one option of salvage therapy. OBJECTIVES: To evaluate a group of 106 patients with Hodgkin's lymphoma, who suffered relapse or who were refractory to treatment, submitted to autologous hematopoietic stem cell transplantation in a single transplant center. METHODS: A retrospective study was performed with data collected from patient charts. The analysis involved 106 classical Hodgkin's lymphoma patients who were consecutively submitted to high-dose chemotherapy followed by autologous transplants in a single institution from April 1993 to December 2006. RESULTS: The overall survival rates of this population at five and ten years were 86% and 70%, respectively. The disease-free survival was approximately 60% at five years. Four patients died of procedure-related causes but relapse of classical Hodgkin's lymphoma after transplant was the most frequent cause of death. Univariate analysis shows that sensitivity to pre-transplant treatment and hemoglobin < 10 g/dL at diagnosis had an impact on patient survival. Unlike other studies, B-type symptoms did not seem to affect overall survival. Lactic dehydrogenase and serum albumin concentrations analyzed at diagnosis did not influence patient survival either. CONCLUSION: Autologous hematopoietic stem cell transplantation is an effective treatment strategy for early and late relapse in classical Hodgkin's lymphoma for cases that were responsive to pre-transplant chemotherapy. Refractory to treatment is a sign of worse prognosis. Additionally, a hemoglobin concentration below 10 g/dL at diagnosis of Hodgkin's lymphoma has a negative impact on the survival of patients after transplant. As far as we know this relationship has not

Clinical aspects and therapy of non-Hodgkin lymphomas

International Nuclear Information System (INIS)

Meissner, K.; Jaenner, M.

1981-01-01

Definition, incidence and distribution of age and sex of cutaneous non-Hodgkin lymphomas are presented. Clinical appearance of cutaneous non-Hodgkin lymphomas may exhibit specific and unspecific cutaneous lesions. Histological examination is of greatest importance for subsequent diagnostic and therapeutic procedures. Topical treatment, X-ray- or photochemotherapy are performed in the early stages, in case of therapeutic resistance and in advanced disease systemical chemotherapy is indicated. (orig.) [de

Parameter Estimation of Nonlinear Models in Forestry.

OpenAIRE

Fekedulegn, Desta; Mac Siúrtáin, Máirtín Pádraig; Colbert, Jim J.

1999-01-01

Partial derivatives of the negative exponential, monomolecular, Mitcherlich, Gompertz, logistic, Chapman-Richards, von Bertalanffy, Weibull and the Richard’s nonlinear growth models are presented. The application of these partial derivatives in estimating the model parameters is illustrated. The parameters are estimated using the Marquardt iterative method of nonlinear regression relating top height to age of Norway spruce (Picea abies L.) from the Bowmont Norway Spruce Thinnin...

Primary Refractory and Relapsed Classical Hodgkin Lymphoma - Significance of Differential CD15 Expression in Hodgkin-Reed-Sternberg Cells

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Daniel Benharroch, Shai Pilosof, Jacob Gopas, Itai Levi

2012-01-01

Full Text Available We recognized a few possible complications of classical Hodgkin lymphoma therapy in a cohort of 209 patients: 8 developed a primary refractory disease (primary progression, 36 showed an early relapse and 21 showed a late relapse. Sialyl-CD15 expression in Hodgkin-Reed-Sternberg cells was significantly more positive in primary refractory Hodgkin lymphoma, which confirms our previously published findings. Bcl-2 showed a significantly lower level of expression in primary refractory disease than in the other follow-up groups. This is in contrast with a previous finding of Bcl-2, associated with a poor prognosis in primary refractory illness. Another category of variables, old age and advanced stages, was significantly different in the various complications but this finding is probably to be expected. We could not demonstrate a difference between the sequels and the control group with regard to several clinical and immunohistochemical markers. Sialyl-CD15 and Bcl-2 expression, in contrast, were confirmed as prognostic factors, mainly of tumor progression into primary refractory disease.

A Simple Model for Nonlinear Confocal Ultrasonic Beams

Science.gov (United States)

Zhang, Dong; Zhou, Lin; Si, Li-Sheng; Gong, Xiu-Fen

2007-01-01

A confocally and coaxially arranged pair of focused transmitter and receiver represents one of the best geometries for medical ultrasonic imaging and non-invasive detection. We develop a simple theoretical model for describing the nonlinear propagation of a confocal ultrasonic beam in biological tissues. On the basis of the parabolic approximation and quasi-linear approximation, the nonlinear Khokhlov-Zabolotskaya-Kuznetsov (KZK) equation is solved by using the angular spectrum approach. Gaussian superposition technique is applied to simplify the solution, and an analytical solution for the second harmonics in the confocal ultrasonic beam is presented. Measurements are performed to examine the validity of the theoretical model. This model provides a preliminary model for acoustic nonlinear microscopy.

Linfoma não-Hodgkin de órbita: relato de caso Non-Hodgkin orbital lymphoma: case report

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Cristiane do Prado Silva

2008-04-01

Full Text Available O objetivo é relatar manifestação incomum de linfoma não-Hodgkin de órbita. Paciente masculino, de 75 anos, se apresentou com queixa de lacrimejamento crônico bilateral. Havia feito dacriocistorrinostomia endonasal à direita e à esquerda por duas vezes, sem sucesso. Ao exame, massas de consistência fibroelástica, em topografia das "bolsas" de gordura das pálpebras inferiores e proptose axial. O paciente negava outros sintomas ou sinais sistêmicos. Hemograma sem alteração, hormônios tireoidianos normais. A tomografia computadorizada mostrava infiltrado difuso na órbita e proptose axial. Biópsia de gordura orbitária e de medula óssea diagnosticaram linfoma não-Hodgkin. O paciente foi tratado com quimioterapia, sendo em seguida submetido à cirurgia da via lacrimal bilateral, com resolução do quadro. A doença sistêmica que exigia diagnóstico e tratamento adequados para que se tivesse bom prognóstico estava mascarada pelo quadro de epífora bilateral.The purpose is to report an unusual case of orbital non-Hodgkin lymphoma. A 75-year-old man presented with bilateral chronic epiphora complaint and inferior eyelid tumors, axial proptosis, without previous systemic manifestation. The patient was submitted to bilateral endonasal dacryocystorhinostomy twice and the epiphora complaint persisted. The inferior eyelid and bone marrow biopsy revealed non-Hodgkin lymphoma. The patient was treated with systemic chemotherapy and dacryocystorhinostomy with good resolution. The precise diagnosis and the treatment were very important to reach a good resolution of the bilateral epiphora complaint.

Brentuximab Vedotin Treatment for Primary Refractory Hodgkin Lymphoma

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Hung-Bo Wu

2013-01-01

Full Text Available Up to 40% of patients with advanced Hodgkin lymphoma (HL become refractory or relapsed after current standard chemotherapy, among which primary refractory HL confers a particularly poor outcome. With intensive salvage chemotherapy and autologous stem cell transplantation, the long-term remission rate for these patients was only 30%, but more selective treatments with higher therapeutic index are needed. We report the experience of using a new anti-CD30 immunotoxin, brentuximab vedotin, in salvage treatment of a 30-year-old woman with primary refractory Hodgkin lymphoma. The patient presented with SVC syndrome due to the bulky mediastinal tumor and was confirmed to have classical Hodgkin lymphoma, nodular sclerosis type, stage IIIA. The tumor responded to induction chemotherapy transiently, but local progression was noted during subsequent cycles of treatment. Salvage radiotherapy to the mediastinal tumor, obtained no remission but was followed by rapid in-field progression and then lung metastasis. She declined stem cell transplantation and received salvage brentuximab vedotin (BV therapy, which induced dramatic shrinkage of tumor without significant side effects. Serial followup of PET/CT imaging confirmed a rapid and continuous complete remission for 12 months. Although durability of the remission needs further observation, this case illustrates the excellent efficacy of brentuximab vedotin in primary refractory Hodgkin lymphoma.

Nonlinear flow model for well production in an underground formation

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J. C. Guo

2013-05-01

Full Text Available Fluid flow in underground formations is a nonlinear process. In this article we modelled the nonlinear transient flow behaviour of well production in an underground formation. Based on Darcy's law and material balance equations, we used quadratic pressure gradients to deduce diffusion equations and discuss the origins of nonlinear flow issues. By introducing an effective-well-radius approach that considers skin factor, we established a nonlinear flow model for both gas and liquid (oil or water. The liquid flow model was solved using a semi-analytical method, while the gas flow model was solved using numerical simulations because the diffusion equation of gas flow is a stealth function of pressure. For liquid flow, a series of standard log-log type curves of pressure transients were plotted and nonlinear transient flow characteristics were analyzed. Qualitative and quantitative analyses were used to compare the solutions of the linear and nonlinear models. The effect of nonlinearity upon pressure transients should not be ignored. For gas flow, pressure transients were simulated and compared with oil flow under the same formation and well conditions, resulting in the conclusion that, under the same volume rate production, oil wells demand larger pressure drops than gas wells. Comparisons between theoretical data and field data show that nonlinear models will describe fluid flow in underground formations realistically and accurately.

Management of breast cancer following Hodgkin's disease

International Nuclear Information System (INIS)

Wolden, Suzanne L.; Carlson, Robert W.; Jeffrey, Stefanie S.; Hancock, Steven L.

1997-01-01

Purpose: To evaluate the incidence, histology, risk factors, treatment, and prognosis of breast cancer occurring after Hodgkin's disease. Materials and Methods: Sixty-five cases of breast cancer in 61 survivors of Hodgkin's lymphoma were analyzed. The median age at treatment for Hodgkin's disease was 24.1 [range (R): 13.3 - 71.8] years. Fifty-one percent had received radiotherapy alone, 47% radiation and chemotherapy, and 2% chemotherapy only. Relative and absolute risks were calculated based on 47 invasive breast cancers in 1049 women treated for Hodgkin's disease at Stanford. Results: The median age at diagnosis of breast cancer was 41.9 (R: 23.0 - 79.1) years; 76% of women were premenopausal. The median interval between Hodgkin's disease and breast cancer was 17.6 (R: 1.5 - 32.7) years with an increasing incidence beginning eight years after radiotherapy. The current relative risk of invasive breast cancer following Hodgkin's disease is 4.7 [95% confidence interval (CI): 3.4 - 6.1] with an absolute risk of 29.5 (CI: 18.8 - 40.2) excess cases per 10,000 person-years. Eighty-seven percent of breast cancers occurred in or at the margin of a prior radiotherapy field where a mean dose of 43.5 (R: 24.0 - 51.0) Gy was delivered. There was a family history of breast cancer in 31% of women. Cancers were detected by self examination (66%), screening mammography (27%), and physician examination (7%). Many tumors (60%) were located in the upper outer quadrants, corresponding to the axillary portion of a mantle field. There were seven cases of carcinoma in situ: six DCIS and one LCIS. The histologic distribution of invasive tumors paralleled that reported in the general population: 4% pure lobular, 35% high grade ductal, 45% intermediate grade ductal, 7% low-grade ductal, 4% tubular, 2% medullary, and 2% mucinous. Estrogen receptors were positive in 59% of evaluable cases. While 90% of invasive tumors were smaller than four centimeters, 96% were managed with mastectomy

Hodgkin's disease: internal mammary lymph nodes relapse diagnosed by Gallium-67 scintigraphy

International Nuclear Information System (INIS)

Ruiz Hernandez, G.; Ampudia, J.; Castillo, F.J.; Romero, C.; Pallardo, Y.; Garcia Conde, J.; Ramos, D.

1999-01-01

This article presents the case of a 62-year-old man with treated Hodgkin's disease who had internal mammary lymph nodes relapse after a complete initial response. These masses were gallium avid. These findings were explained by histologically documented Hodgkin's relapse, the first such case reported in that localization without chest wall involvement. The literature on mediastinal Hodgkin's disease and diagnostic procedures are reviewed. (orig.) [de

Open questions in the management of nodular lymphocyte predominant hodgkin lymphoma.

Science.gov (United States)

Tyran, Marguerite; Gonzague, Laurence; Bouabdallah, Reda; Resbeut, Michel

2014-01-01

Localized Nodular Lymphocyte Predominant Hodgkin Lymphoma is a rare disease with an overall good prognosis but frequent late relapses. Due to it's rarity there is no standard therapeutic approach and pathological diagnosis may be hard. In this paper we discuss the technical aspects of the radiation therapy and histological issues. The new fields reductions proposed for classical Hodgkin lymphoma cannot be applied to early stages Nodular Lymphocyte Predominant Hodgkin lymphomas which are usually treated with radiation therapy without systemic chemotherapy.

PA03.13. Effect of triphaladi rasayana along with yoga therapy on low grade non hodgkins lymphoma and resistant intermediate and high grade non hodgkins lymphoma

Science.gov (United States)

Soumya, MS Surya; Sarasa, TP

2013-01-01

Purpose: 1. To find out the effect of Thriphaladi Rasayana along with Yoga Therapy on low grade Non Hodgkins Lymphoma and resistant intermediate and high grade NonHodgkins Lymphoma. 2. To apply a less costly, less morbid, well accepted method of treatment on NHL. 3.To find a simple method to increase the immunity. 4.To try a drug which is easy to prepare? Method: Purposive sampling technique was used for the study. Sample of 30 patients age range 25 75 years with histologicaly proven NonHodgkins lymphoma, attending the M.O.I.O.P of the regional cancer centre during a period of 18 months. Groups1) Low grade NonHodgkins Lymphoma 2) Resistant intermediate &High grade NonHodgkins lymphoma (failed chemotherapy) were taken. Procedure : 2 groups were given Triphaladhi Rasayana (15 grams of powder with ghee and honey) twice dailymorning& at bed time with milk as anupana for period of 1month along with selected yoga asanas and niyama? Result: Symptoms included were fever, night sweats, weight loss, lymph nodes enlargement, splenomegaly, and hepatomegaly. In low grade symptom relief was noted in almost all cases. Lymph node changes notedLow grade5 2% (complete remission), 38% (partial remission), 10% (no change), intermediate35% (CR), 52% (PR) & 13% (NC), High grade67% (CR), 33%(PR). Hepatomegaly changes :ve in low grade92.86%, intermediate 90.9% & high grade100%. Splenomegaly changes :ve in low grade92.86%, intermediate72.72% & high grade80% Over all remission status of 30 patientscomplete remission30%, partial remission 30% & no change30%? Conclusion: Thriphaladirasayana along with Yoga therapy is very effective in Low grade NonHodgkins lymphoma and resistant intermediate and high grade Non hodgkins Lymphoma?

Nonlinear Kalman Filtering in Affine Term Structure Models

DEFF Research Database (Denmark)

Christoffersen, Peter; Dorion, Christian; Jacobs, Kris

When the relationship between security prices and state variables in dynamic term structure models is nonlinear, existing studies usually linearize this relationship because nonlinear fi…ltering is computationally demanding. We conduct an extensive investigation of this linearization and analyze...... the potential of the unscented Kalman …filter to properly capture nonlinearities. To illustrate the advantages of the unscented Kalman …filter, we analyze the cross section of swap rates, which are relatively simple non-linear instruments, and cap prices, which are highly nonlinear in the states. An extensive...

Nonlinear Growth Models in M"plus" and SAS

Science.gov (United States)

Grimm, Kevin J.; Ram, Nilam

2009-01-01

Nonlinear growth curves or growth curves that follow a specified nonlinear function in time enable researchers to model complex developmental patterns with parameters that are easily interpretable. In this article we describe how a variety of sigmoid curves can be fit using the M"plus" structural modeling program and the nonlinear…

Nonlinear Dynamic Models in Advanced Life Support

Science.gov (United States)

Jones, Harry

2002-01-01

To facilitate analysis, ALS systems are often assumed to be linear and time invariant, but they usually have important nonlinear and dynamic aspects. Nonlinear dynamic behavior can be caused by time varying inputs, changes in system parameters, nonlinear system functions, closed loop feedback delays, and limits on buffer storage or processing rates. Dynamic models are usually cataloged according to the number of state variables. The simplest dynamic models are linear, using only integration, multiplication, addition, and subtraction of the state variables. A general linear model with only two state variables can produce all the possible dynamic behavior of linear systems with many state variables, including stability, oscillation, or exponential growth and decay. Linear systems can be described using mathematical analysis. Nonlinear dynamics can be fully explored only by computer simulations of models. Unexpected behavior is produced by simple models having only two or three state variables with simple mathematical relations between them. Closed loop feedback delays are a major source of system instability. Exceeding limits on buffer storage or processing rates forces systems to change operating mode. Different equilibrium points may be reached from different initial conditions. Instead of one stable equilibrium point, the system may have several equilibrium points, oscillate at different frequencies, or even behave chaotically, depending on the system inputs and initial conditions. The frequency spectrum of an output oscillation may contain harmonics and the sums and differences of input frequencies, but it may also contain a stable limit cycle oscillation not related to input frequencies. We must investigate the nonlinear dynamic aspects of advanced life support systems to understand and counter undesirable behavior.

Nonlinear Eddy Viscosity Models applied to Wind Turbine Wakes

DEFF Research Database (Denmark)

Laan, van der, Paul Maarten; Sørensen, Niels N.; Réthoré, Pierre-Elouan

2013-01-01

The linear k−ε eddy viscosity model and modified versions of two existing nonlinear eddy viscosity models are applied to single wind turbine wake simulations using a Reynolds Averaged Navier-Stokes code. Results are compared with field wake measurements. The nonlinear models give better results...

Topological approximation of the nonlinear Anderson model

Science.gov (United States)

Milovanov, Alexander V.; Iomin, Alexander

2014-06-01

We study the phenomena of Anderson localization in the presence of nonlinear interaction on a lattice. A class of nonlinear Schrödinger models with arbitrary power nonlinearity is analyzed. We conceive the various regimes of behavior, depending on the topology of resonance overlap in phase space, ranging from a fully developed chaos involving Lévy flights to pseudochaotic dynamics at the onset of delocalization. It is demonstrated that the quadratic nonlinearity plays a dynamically very distinguished role in that it is the only type of power nonlinearity permitting an abrupt localization-delocalization transition with unlimited spreading already at the delocalization border. We describe this localization-delocalization transition as a percolation transition on the infinite Cayley tree (Bethe lattice). It is found in the vicinity of the criticality that the spreading of the wave field is subdiffusive in the limit t →+∞. The second moment of the associated probability distribution grows with time as a power law ∝ tα, with the exponent α =1/3 exactly. Also we find for superquadratic nonlinearity that the analog pseudochaotic regime at the edge of chaos is self-controlling in that it has feedback on the topology of the structure on which the transport processes concentrate. Then the system automatically (without tuning of parameters) develops its percolation point. We classify this type of behavior in terms of self-organized criticality dynamics in Hilbert space. For subquadratic nonlinearities, the behavior is shown to be sensitive to the details of definition of the nonlinear term. A transport model is proposed based on modified nonlinearity, using the idea of "stripes" propagating the wave process to large distances. Theoretical investigations, presented here, are the basis for consistency analysis of the different localization-delocalization patterns in systems with many coupled degrees of freedom in association with the asymptotic properties of the

A non-linear state space approach to model groundwater fluctuations

NARCIS (Netherlands)

Berendrecht, W.L.; Heemink, A.W.; Geer, F.C. van; Gehrels, J.C.

2006-01-01

A non-linear state space model is developed for describing groundwater fluctuations. Non-linearity is introduced by modeling the (unobserved) degree of water saturation of the root zone. The non-linear relations are based on physical concepts describing the dependence of both the actual

Hodgkin's disease of the prostate: a detailed case report

International Nuclear Information System (INIS)

Klotz, L.H.; Herr, H.W.

1986-01-01

Malignant lymphoma of the prostate is an unusual entity, and nonHodgkin's lymphoma constitutes most reported cases. We report a well documented case of Hodgkin's lymphoma, initially involving the gastrointestinal tract and spleen, which recurred in the prostate following initial remission with chemotherapy. Treatment with external beam radiotherapy resulted in a rapid complete response that has been sustained for 18 months

Augmented twin-nonlinear two-box behavioral models for multicarrier LTE power amplifiers.

Science.gov (United States)

Hammi, Oualid

2014-01-01

A novel class of behavioral models is proposed for LTE-driven Doherty power amplifiers with strong memory effects. The proposed models, labeled augmented twin-nonlinear two-box models, are built by cascading a highly nonlinear memoryless function with a mildly nonlinear memory polynomial with cross terms. Experimental validation on gallium nitride based Doherty power amplifiers illustrates the accuracy enhancement and complexity reduction achieved by the proposed models. When strong memory effects are observed, the augmented twin-nonlinear two-box models can improve the normalized mean square error by up to 3 dB for the same number of coefficients when compared to state-of-the-art twin-nonlinear two-box models. Furthermore, the augmented twin-nonlinear two-box models lead to the same performance as previously reported twin-nonlinear two-box models while requiring up to 80% less coefficients.

A nonlinear model for AC induced corrosion

Directory of Open Access Journals (Sweden)

N. Ida

2012-09-01

Full Text Available The modeling of corrosion poses particular difficulties. The understanding of corrosion as an electrochemical process has led to simple capacitive-resistive models that take into account the resistance of the electrolytic cell and the capacitive effect of the surface potential at the interface between conductors and the electrolyte. In some models nonlinear conduction effects have been added to account for more complex observed behavior. While these models are sufficient to describe the behavior in systems with cathodic protection, the behavior in the presence of induced AC currents from power lines and from RF sources cannot be accounted for and are insufficient to describe the effects observed in the field. Field observations have shown that a rectifying effect exists that affects the cathodic protection potential and this effect is responsible for corrosion in the presence of AC currents. The rectifying effects of the metal-corrosion interface are totally missing from current models. This work proposes a nonlinear model based on finite element analysis that takes into account the nonlinear behavior of the metal-oxide interface and promises to improve modeling by including the rectification effects at the interface.

Comparison of a nonlinear dynamic model of a piping system to test data

International Nuclear Information System (INIS)

Blakely, K.D.; Howard, G.E.; Walton, W.B.; Johnson, B.A.; Chitty, D.E.

1983-01-01

Response of a nonlinear finite element model of the Heissdampfreaktor recirculation piping loop (URL) was compared to measured data, representing the physical benchmarking of a nonlinear model. Analysis-test comparisons of piping response are presented for snapback tests that induced extreme nonlinear behavior of the URL system. Nonlinearities in the system are due to twelve swaybraces (pipe supports) that possessed nonlinear force-deflection characteristics. These nonlinearities distorted system damping estimates made by using the half-power bandwidth method on Fourier transforms of measured accelerations, with the severity of distortion increasing with increasing degree of nonlinearity. Time domain methods, which are not so severely affected by the presence of nonlinearities, were used to compute system damping ratios. Nonlinear dynamic analyses were accurately and efficiently performed using the pseudo-force technique and the finite element program MSC/NASTRAN. Measured damping was incorporated into the model for snapback simulations. Acceleration time histories, acceleration Fourier transforms, and swaybrace force time histories of the nonlinear model, plus several linear models, were compared to test measurements. The nonlinear model predicted three-fourths of the measured peak accelerations to within 50%, half of the accelerations to within 25%, and one-fifth of the accelerations to within 10%. This nonlinear model predicted accelerations (in the time and frequency domains) and swaybrace forces much better than did any of the linear models, demonstrating the increased accuracy resulting from properly simulating nonlinear support behavior. In addition, earthquake response comparisons were made between the experimentally validated nonlinear model and a linear model. Significantly lower element stresses were predicted for the nonlinear model, indicating the potential usefulness of nonlinear simulations in piping design assessments. (orig.)

Environmental risk factors related to the development of canine non-Hodgkin's lymphoma Fatores de risco ambientais relacionados ao desenvolvimento do linfoma não Hodgkin canino

Directory of Open Access Journals (Sweden)

Danielle Almeida Zanini

2013-01-01

Full Text Available This research aimed to investigate the possible risk factors associated with the development of canine non-Hodgkin's lymphoma. Owners of 83 dogs with non-Hodgkin's lymphoma and of 84 healthy dogs answered an epidemiological questionnaire. Dogs who lived outside of the house and within 100 meters of busy streets or avenues (defined as more than 50 vehicles per minute had a higher risk for developing the disease (OR: 3.1, 95% CI: 1.4-6.9, P=0.005. These results suggest that air pollution derived from vehicle traffic may be associated with the development of canine non-Hodgkin's lymphoma.Este trabalho teve como objetivo investigar os possíveis fatores de risco ambientais, associados com o desenvolvimento de linfoma não-Hodgkin nos cães. Um questionário epidemiológico foi aplicado aos proprietários de 83 cães com linfoma não-Hodgkin e 84 proprietários de cães saudáveis. Os cães que viviam permanentemente no lado de fora da casa e em torno de 100 metros de ruas movimentadas ou avenidas (mais de 50 veículos por minuto tiveram um maior risco de desenvolvimento da doença (OR: 3,1, IC 95%: 1,4-6,9, P=0,005. Esses resultados sugerem que a poluição do ar oriunda do tráfego veicular pode estar associada com o desenvolvimento de linfomas não-Hodgkin canino.

Association between simian virus 40 and non-Hodgkin lymphoma

Science.gov (United States)

Vilchez, Regis A.; Madden, Charles R.; Kozinetz, Claudia A.; Halvorson, Steven J.; White, Zoe S.; Jorgensen, Jeffrey L.; Finch, Chris J.; Butel, Janet S.

2002-01-01

BACKGROUND: Non-Hodgkin lymphoma has increased in frequency over the past 30 years, and is a common cancer in HIV-1-infected patients. Although no definite risk factors have emerged, a viral cause has been postulated. Polyomaviruses are known to infect human beings and to induce tumours in laboratory animals. We aimed to identify which one of the three polyomaviruses able to infect human beings (simian virus 40 [SV40], JC virus, and BK virus) was associated with non-Hodgkin lymphoma. METHODS: We analysed systemic non-Hodgkin lymphoma from 76 HIV-1-infected and 78 HIV-1-uninfected patients, and non-malignant lymphoid samples from 79 HIV-1-positive and 107 HIV-1-negative patients without tumours; 54 colon and breast carcinoma samples served as cancer controls. We used PCR followed by Southern blot hybridisation and DNA sequence analysis to detect DNAs of polyomaviruses and herpesviruses. FINDINGS: Polyomavirus T antigen sequences, all of which were SV40-specific, were detected in 64 (42%) of 154 non-Hodgkin lymphomas, none of 186 non-malignant lymphoid samples, and none of 54 control cancers. This difference was similar for HIV-1-infected patients and HIV-1-uninfected patients alike. Few tumours were positive for both SV40 and Epstein-Barr virus. Human herpesvirus type 8 was not detected. SV40 sequences were found most frequently in diffuse large B-cell and follicular-type lymphomas. INTERPRETATION: SV40 is significantly associated with some types of non-Hodgkin lymphoma. These results add lymphomas to the types of human cancers associated with SV40.

Background field method for nonlinear σ-model in stochastic quantization

International Nuclear Information System (INIS)

Nakazawa, Naohito; Ennyu, Daiji

1988-01-01

We formulate the background field method for the nonlinear σ-model in stochastic quantization. We demonstrate a one-loop calculation for a two-dimensional non-linear σ-model on a general riemannian manifold based on our formulation. The formulation is consistent with the known results in ordinary quantization. As a simple application, we also analyse the multiplicative renormalization of the O(N) nonlinear σ-model. (orig.)

Modeling Non-Linear Material Properties in Composite Materials

Science.gov (United States)

2016-06-28

Technical Report ARWSB-TR-16013 MODELING NON-LINEAR MATERIAL PROPERTIES IN COMPOSITE MATERIALS Michael F. Macri Andrew G...REPORT TYPE Technical 3. DATES COVERED (From - To) 4. TITLE AND SUBTITLE MODELING NON-LINEAR MATERIAL PROPERTIES IN COMPOSITE MATERIALS ...systems are increasingly incorporating composite materials into their design. Many of these systems subject the composites to environmental conditions

Data assimilation using a GPU accelerated path integral Monte Carlo approach

Science.gov (United States)

Quinn, John C.; Abarbanel, Henry D. I.

2011-09-01

The answers to data assimilation questions can be expressed as path integrals over all possible state and parameter histories. We show how these path integrals can be evaluated numerically using a Markov Chain Monte Carlo method designed to run in parallel on a graphics processing unit (GPU). We demonstrate the application of the method to an example with a transmembrane voltage time series of a simulated neuron as an input, and using a Hodgkin-Huxley neuron model. By taking advantage of GPU computing, we gain a parallel speedup factor of up to about 300, compared to an equivalent serial computation on a CPU, with performance increasing as the length of the observation time used for data assimilation increases.

Lymphocyte-predominant Hodgkin disease: a comprehensive overview.

Science.gov (United States)

Bose, Sumit; Ganesan, Chitra; Pant, Manish; Lai, Catherine; Tabbara, Imad A

2013-02-01

Lymphocyte-predominant Hodgkin disease is a rare form of Hodgkin lymphoma that is recognized as a separate histopathological entity. This disease tends to have multiple relapses, but has an overall good prognosis. Owing to its rarity, and the prolonged time period between recurrence and transformation events, there is no consensus regarding optimal management. However, the National Comprehensive Cancer Network guidelines indicate that for early stages, appropriate treatment is radiotherapy. Several management options have been reported including observation, radiation, chemotherapy, combined chemoradiotherapy, and anti-CD20 antibody therapy. Salvage therapy remains effective in inducing prolonged remission in patients with relapsed/refractory disease.

Breast Cancer After Treatment of Hodgkin's Lymphoma: General Review

International Nuclear Information System (INIS)

Alm El-Din, Mohamed A.; El-Badawy, Samy A.; Taghian, Alphonse G.

2008-01-01

The improved survival rates among patients with Hodgkin's lymphoma over the past few decades have come with increased incidence of second malignancies. One of the major concerns among female survivors is the significantly elevated risk of breast cancer that appears with extended follow-up. In this review, we include the published literature regarding the risk of breast cancer after irradiation for Hodgkin's lymphoma. We also present the possible long-term surveillance strategies and the optimal time to start screening these women. This could potentially help in early detection of secondary breast cancers and consequently improve outcomes. Furthermore, because of prior radiotherapy, the management of the breast cancer among this unique population has been controversial. We discuss the characteristics of breast cancer that occurs after Hodgkin's lymphoma and also treatment options that could be implemented

From Knights Corner to Landing: a Case Study Based on a Hodgkin-Huxley Neuron Simulator

OpenAIRE

George Chatzikonstantis; Diego Jiménez; Esteban Meneses; Christos Strydis; Harry Sidiropoulos; Dimitrios Soudris

2017-01-01

Brain modeling has been presenting significant challenges to the world of high-performance computing (HPC) over the years. The field of computational neuroscience has been developing a demand for physiologically plausible neuron models, that feature increased complexity and thus, require greater computational power. We explore Intel’s newest generation of Xeon Phi computing platforms, named Knights Landing (KNL), as a way to match the need for processing power and as an upgrade over the previ...

A deep belief network with PLSR for nonlinear system modeling.

Science.gov (United States)

Qiao, Junfei; Wang, Gongming; Li, Wenjing; Li, Xiaoli

2017-10-31

Nonlinear system modeling plays an important role in practical engineering, and deep learning-based deep belief network (DBN) is now popular in nonlinear system modeling and identification because of the strong learning ability. However, the existing weights optimization for DBN is based on gradient, which always leads to a local optimum and a poor training result. In this paper, a DBN with partial least square regression (PLSR-DBN) is proposed for nonlinear system modeling, which focuses on the problem of weights optimization for DBN using PLSR. Firstly, unsupervised contrastive divergence (CD) algorithm is used in weights initialization. Secondly, initial weights derived from CD algorithm are optimized through layer-by-layer PLSR modeling from top layer to bottom layer. Instead of gradient method, PLSR-DBN can determine the optimal weights using several PLSR models, so that a better performance of PLSR-DBN is achieved. Then, the analysis of convergence is theoretically given to guarantee the effectiveness of the proposed PLSR-DBN model. Finally, the proposed PLSR-DBN is tested on two benchmark nonlinear systems and an actual wastewater treatment system as well as a handwritten digit recognition (nonlinear mapping and modeling) with high-dimension input data. The experiment results show that the proposed PLSR-DBN has better performances of time and accuracy on nonlinear system modeling than that of other methods. Copyright © 2017 Elsevier Ltd. All rights reserved.

Functional hyposplenia after splenic irradiation for Hodgkin's disease

International Nuclear Information System (INIS)

Coleman, C.N.; McDougall, I.R.; Dailey, M.O.; Ager, P.; Bush, S.; Kaplan, H.S.

1982-01-01

We previously reported a patients who developed fulminant pneumococcal sepsis 12 years after successful treatment for Hodgkin's disease, which included splenic irradiation. We have since evaluated splenic size and function in 25 patients who had received splenic irradiation 5 to 16 years previously either for Hodgkin's disease (n . 19) or non-Hodgkin's lymphoma (n . 6). Mean maximum splenic diameter as measured on a 99mTc-sulfur colloid liver-spleen scan was 6.2 cm in the irradiated group and 9.7 cm in a control group (p less than 0.001). The mean percentage of erythrocytes containing pits when observed with interference phase microscopy was 13.0% in the irradiated group, which was significantly different (p less than 0.001) from the levels found in each of the control groups: normal subjects, 0.9%; unstaged and untreated lymphoma patients, 0.6%; and patients after splenectomy, 33.7%. Patients who have had splenic irradiation should be considered at risk of developing overwhelming pneumococcal sepsis

Hodgkin's lymphoma arising in a case of mycosis fungoides: An unusual association

Directory of Open Access Journals (Sweden)

Preeti Sharma

2018-01-01

Full Text Available Mycosis fungoides is a cutaneous T-cell lymphoma with a high risk for developing secondary malignancies, especially B-cell lymphoproliferative disorders. About 40 cases of Hodgkin's lymphoma associated with mycosis fungoides have been reported in literature till date. We report a case of a 35-year-old gentleman who presented with intensely itchy reddish lesions all over the body. Multiple skin biopsies taken from the lesions on scalp and back confirmed the clinical diagnosis of mycosis fungoides. While on treatment, he presented with multiple bilateral cervical, axillary and inguinal lymphadenopathy 9 years after the primary diagnosis of mycosis fungoides. Excision biopsy of a cervical lymph node revealed partial effacement of architecture by a tumor comprising polymorphous background. Histopathology and immunohistochemistry revealed a diagnosis of Hodgkin's lymphoma - nodular sclerosis subtype. The patient was started on chemotherapy for stage IV Hodgkin's lymphoma. Our case emphasizes the importance of keeping secondary Hodgkin's lymphoma in mind while dealing with a patient of mycosis fungoides. Our case immunohistochemically supports the distinct etiopathogenesis of Epstein–Barr virus-negative Hodgkin's lymphoma vis-à-vis cutaneous mycosis fungoides.

Nodal involvement in Hodgkin disease and non-Hodgkin lymphoma assessed by magnetic resonance

International Nuclear Information System (INIS)

Tesoro Tess, J.D.; Balzarini, L.; Ceglia, E.; Petrillo, R.; Musumeci, R.

1990-01-01

Magnetic Resonance Imaging (MRI) demonstrates a good capability in distinguishing nodal involvement in hodgkin disease and nonhodgkin lymphoma both in the chest and in the retroperitoneal areas the initial presentation of the disease. However CT and lymphangiography demonstrated comparable or superior values of accuracy and sensitivity. (H.W.) 4 refs.; 2 tabs

Quasilinear Extreme Learning Machine Model Based Internal Model Control for Nonlinear Process

Directory of Open Access Journals (Sweden)

Dazi Li

2015-01-01

Full Text Available A new strategy for internal model control (IMC is proposed using a regression algorithm of quasilinear model with extreme learning machine (QL-ELM. Aimed at the chemical process with nonlinearity, the learning process of the internal model and inverse model is derived. The proposed QL-ELM is constructed as a linear ARX model with a complicated nonlinear coefficient. It shows some good approximation ability and fast convergence. The complicated coefficients are separated into two parts. The linear part is determined by recursive least square (RLS, while the nonlinear part is identified through extreme learning machine. The parameters of linear part and the output weights of ELM are estimated iteratively. The proposed internal model control is applied to CSTR process. The effectiveness and accuracy of the proposed method are extensively verified through numerical results.

Theoretical models for ultrashort electromagnetic pulse propagation in nonlinear metamaterials

International Nuclear Information System (INIS)

Wen, Shuangchun; Xiang, Yuanjiang; Dai, Xiaoyu; Tang, Zhixiang; Su, Wenhua; Fan, Dianyuan

2007-01-01

A metamaterial (MM) differs from an ordinary optical material mainly in that it has a dispersive magnetic permeability and offers greatly enhanced design freedom to alter the linear and nonlinear properties. This makes it possible for us to control the propagation of ultrashort electromagnetic pulses at will. Here we report on generic features of ultrashort electromagnetic pulse propagation and demonstrate the controllability of both the linear and nonlinear parameters of models for pulse propagation in MMs. First, we derive a generalized system of coupled three-dimensional nonlinear Schroedinger equations (NLSEs) suitable for few-cycle pulse propagation in a MM with both nonlinear electric polarization and nonlinear magnetization. The coupled equations recover previous models for pulse propagation in both ordinary material and a MM under the same conditions. Second, by using the coupled NLSEs in the Drude dispersive model as an example, we identify the respective roles of the dispersive electric permittivity and magnetic permeability in ultrashort pulse propagation and disclose some additional features of pulse propagation in MMs. It is shown that, for linear propagation, the sign and magnitude of space-time focusing can be controlled through adjusting the linear dispersive permittivity and permeability. For nonlinear propagation, the linear dispersive permittivity and permeability are incorporated into the nonlinear magnetization and nonlinear polarization, respectively, resulting in controllable magnetic and electric self-steepening effects and higher-order dispersively nonlinear terms in the propagation models

Expression of Epstein-Barr virus in Hodgkin lymphoma Specimens in IRAN.

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Laila Mozafari

2013-09-01

Full Text Available  Background &Objectives: The Epstein-Barr Virus (EBV( is related with various diseases including infectious mononucleosis, Burkitt's lymphoma, Hodgkin's lymphoma, nasopharyngeal carcinoma and post-transplant lymphoprolifrative disorders. The aim of this study was to characterize the association between EBV and Hodgkin's lymphoma through EBERs in situ hybridization (EBER-ISH in Iranian patients.    Materials &Methods: In this study, 43 Hodgkin's lymphoma tissue samples were selected from formalin-fixed paraffin embedded blocks and analyzed by EBERs in situ hybridization. Data analyzed by SPSS16 statistical software, Fisher's exact test and Mantel-Haensel significant level 0.05.   Results: 43 Hodgkin's lymphoma patients were 29 (67% male samples and 14 (33% female samples. In 20 (47% samples Epstein-Barr virus was present. The positive cases included 13 samples  male and 7 samples female. Fisher's exact test showed statistically no significant difference between sex and subtypes. Age distribution of relation of Hodgkin's lymphoma and EBV virus were 75% (12 of 16 in the age group of 1-14 years,  22% (5 of 23 in the age group 15-49 years and 75% (3 of 4 in the age group over 49 years, respectively. Fisher's exact test showed statistically significant difference between 1-14 and 15-49 age group years (p-value: 0.003.   Conclusion: Results shown higher presence rate of Epstein-Barr virus in Hodgkin's lymphoma specimens  of children and older adult. This pattern is similar to other developing countries. 

Drugs Approved for Hodgkin Lymphoma

Science.gov (United States)

This page lists cancer drugs approved by the Food and Drug Administration (FDA) for Hodgkin lymphoma. The list includes generic names, brand names, and common drug combinations, which are shown in capital letters. The drug names link to NCI's Cancer Drug Information summaries.

Preisach hysteresis model for non-linear 2D heat diffusion

International Nuclear Information System (INIS)

Jancskar, Ildiko; Ivanyi, Amalia

2006-01-01

This paper analyzes a non-linear heat diffusion process when the thermal diffusivity behaviour is a hysteretic function of the temperature. Modelling this temperature dependence, the discrete Preisach algorithm as general hysteresis model has been integrated into a non-linear multigrid solver. The hysteretic diffusion shows a heating-cooling asymmetry in character. The presented type of hysteresis speeds up the thermal processes in the modelled systems by a very interesting non-linear way

Thyroid dysfunction after mantle irradiation of Hodgkin`s disease patients

Energy Technology Data Exchange (ETDEWEB)

Khoo, V.S.; Liew, K.H.; Crennan, E.C.; D`Costa, I.M. [Peter MacCallum Caner Institute, East Melbourne, VIC (Australia). Department of Radiation Oncology; Quong, G. [Austin and Repatriation Medical Centre, West Heidelberg, VIC (Australia). Department of Radiation Oncology

1998-02-01

Thyroid dysfunction can develop in patients with Hodgkin`s disease who are treated with mantle irradiation. During the period 1970-89, the records of 320 patients who received mantle irradiation and who had thyroid function tests (TFT) were retrospectively reviewed. The median age was 30 years (range, 7-69 years). The median mantle and thyroid dose was 36 Gy (range, 30-40 Gy) and 39.8 Gy (range, 32-65 Gy), respectively. Overall thyroid dysfunction was present in 39% of the patients. Clinical hypothyroidism was seen in 10% and biochemical hypothyroidism was noted in 25%. Hyperthyroidism was found in 4% of patients. Thyroid nodules had developed in six patients (2%), of which those in four patients were malignant. Age, sex, histological subtype, stage of disease, dose, Iymphangiogram and treatment with chemotherapy were not significant factors in the development of thyroid dysfunction. The narrow dose range prevented adequate analysis of dose effect. The results indicate that the incidence of thyroid abnormalities is high enough to warrant regular TFT assessment with pre-irradiation levels and follow-up testing for life because the development of abnormalities can occur many years later. Thyroid examination should form part of the routine follow-up examination and any abnormality should be promptly investigated. Copyright (1998) Blackwell Science Pty Ltd 32 refs., 3 tabs.

Robust model predictive control for constrained continuous-time nonlinear systems

Science.gov (United States)

Sun, Tairen; Pan, Yongping; Zhang, Jun; Yu, Haoyong

2018-02-01

In this paper, a robust model predictive control (MPC) is designed for a class of constrained continuous-time nonlinear systems with bounded additive disturbances. The robust MPC consists of a nonlinear feedback control and a continuous-time model-based dual-mode MPC. The nonlinear feedback control guarantees the actual trajectory being contained in a tube centred at the nominal trajectory. The dual-mode MPC is designed to ensure asymptotic convergence of the nominal trajectory to zero. This paper extends current results on discrete-time model-based tube MPC and linear system model-based tube MPC to continuous-time nonlinear model-based tube MPC. The feasibility and robustness of the proposed robust MPC have been demonstrated by theoretical analysis and applications to a cart-damper springer system and a one-link robot manipulator.

Modelling female fertility traits in beef cattle using linear and non-linear models.

Science.gov (United States)

Naya, H; Peñagaricano, F; Urioste, J I

2017-06-01

Female fertility traits are key components of the profitability of beef cattle production. However, these traits are difficult and expensive to measure, particularly under extensive pastoral conditions, and consequently, fertility records are in general scarce and somehow incomplete. Moreover, fertility traits are usually dominated by the effects of herd-year environment, and it is generally assumed that relatively small margins are kept for genetic improvement. New ways of modelling genetic variation in these traits are needed. Inspired in the methodological developments made by Prof. Daniel Gianola and co-workers, we assayed linear (Gaussian), Poisson, probit (threshold), censored Poisson and censored Gaussian models to three different kinds of endpoints, namely calving success (CS), number of days from first calving (CD) and number of failed oestrus (FE). For models involving FE and CS, non-linear models overperformed their linear counterparts. For models derived from CD, linear versions displayed better adjustment than the non-linear counterparts. Non-linear models showed consistently higher estimates of heritability and repeatability in all cases (h 2  linear models; h 2  > 0.23 and r > 0.24, for non-linear models). While additive and permanent environment effects showed highly favourable correlations between all models (>0.789), consistency in selecting the 10% best sires showed important differences, mainly amongst the considered endpoints (FE, CS and CD). In consequence, endpoints should be considered as modelling different underlying genetic effects, with linear models more appropriate to describe CD and non-linear models better for FE and CS. © 2017 Blackwell Verlag GmbH.

Nonlinear Dynamic Modeling of Langevin-Type Piezoelectric Transducers

Directory of Open Access Journals (Sweden)

Nicolás Peréz Alvarez

2015-11-01

Full Text Available Langevin transducers are employed in several applications, such as power ultrasound systems, naval hydrophones, and high-displacement actuators. Nonlinear effects can influence their performance, especially at high vibration amplitude levels. These nonlinear effects produce variations in the resonant frequency, harmonics of the excitation frequency, in addition to loss of symmetry in the frequency response and “frequency domain hysteresis”. In this context, this paper presents a simplified nonlinear dynamic model of power ultrasound transducers requiring only two parameters for simulating the most relevant nonlinear effects. One parameter reproduces the changes in the resonance frequency and the other introduces the dependence of the frequency response on the history of the system. The piezoelectric constitutive equations are extended by a linear dependence of the elastic constant on the mechanical displacement amplitude. For introducing the frequency hysteresis, the elastic constant is computed by combining the current value of the mechanical amplitude with the previous state amplitude. The model developed in this work is applied for predicting the dynamic responses of a 26 kHz ultrasonic transducer. The comparison of theoretical and experimental responses, obtained at several input voltages around the tuned frequency, shows a good agreement, indicating that the model can accurately describe the transducer nonlinear behavior.

Mathematical models of human paralyzed muscle after long-term training.

Science.gov (United States)

Law, L A Frey; Shields, R K

2007-01-01

Spinal cord injury (SCI) results in major musculoskeletal adaptations, including muscle atrophy, faster contractile properties, increased fatigability, and bone loss. The use of functional electrical stimulation (FES) provides a method to prevent paralyzed muscle adaptations in order to sustain force-generating capacity. Mathematical muscle models may be able to predict optimal activation strategies during FES, however muscle properties further adapt with long-term training. The purpose of this study was to compare the accuracy of three muscle models, one linear and two nonlinear, for predicting paralyzed soleus muscle force after exposure to long-term FES training. Further, we contrasted the findings between the trained and untrained limbs. The three models' parameters were best fit to a single force train in the trained soleus muscle (N=4). Nine additional force trains (test trains) were predicted for each subject using the developed models. Model errors between predicted and experimental force trains were determined, including specific muscle force properties. The mean overall error was greatest for the linear model (15.8%) and least for the nonlinear Hill Huxley type model (7.8%). No significant error differences were observed between the trained versus untrained limbs, although model parameter values were significantly altered with training. This study confirmed that nonlinear models most accurately predict both trained and untrained paralyzed muscle force properties. Moreover, the optimized model parameter values were responsive to the relative physiological state of the paralyzed muscle (trained versus untrained). These findings are relevant for the design and control of neuro-prosthetic devices for those with SCI.

Bilateral breast cancer after cured Hodgkin's disease

Energy Technology Data Exchange (ETDEWEB)

Anderson, N.; Lokich, J. (New England Baptist Hospital, Boston, MA (USA))

1990-01-15

Three patients developed bilateral breast cancer at 10 to 24 years after mantle irradiation for locally or systemically advanced Hodgkin's disease (HD). Four of the six cancers in the three patients were detected only by mammography. Pathologically, five of the cancers were intraductal carcinomas (four with an invasive component) with one being a lobular carcinoma. Five of the six lesions were Stage I pathologically without evidence of axillary nodal involvement. It is recommended that female patients with Hodgkin's disease who have received mantle irradiation as part of the therapy for their Hodgkin's disease and who are observed for 10 or more years after completion of mantle irradiation be considered at risk for the development of breast cancer. Such patients should be monitored appropriately by routine bilateral mammograms to increase the early detection of early stage lesions.

Acute myelomonocytic leukemia following splenectomy in a patient with long-standing Hodgkin disease

International Nuclear Information System (INIS)

Rosenbloom, B.E.; Klein, E.J.; Uszler, J.M.; Ellis, R.; Block, J.B.; Tanaka, K.R.

1978-01-01

The association of acute nonlymphocytic leukemia with Hodgkin disease has been recorded in more than 100 instances. In most of these cases the patient has had long-standing Hodgkin disease and radiotherapy has been carried out. The combination of previous radiotherapy and chemotherapy appears to further increase the risk of leukemia developing. In a patient under our care with Hodgkin disease acute myelomonocytic leukemia developed following splenectomy for hypersplenism. The onset of acute leukemia immediately following splenectomy in a patient with Hodgkin disease has not previously been noted. In addition, because the patient's usual bone marrow sampling sites were hypoplastic, we utilized an 111 In-chloride bone marrow scan to find a site that was accessible for aspiration

Perturbation analysis of nonlinear matrix population models

Directory of Open Access Journals (Sweden)

Hal Caswell

2008-03-01

Full Text Available Perturbation analysis examines the response of a model to changes in its parameters. It is commonly applied to population growth rates calculated from linear models, but there has been no general approach to the analysis of nonlinear models. Nonlinearities in demographic models may arise due to density-dependence, frequency-dependence (in 2-sex models, feedback through the environment or the economy, and recruitment subsidy due to immigration, or from the scaling inherent in calculations of proportional population structure. This paper uses matrix calculus to derive the sensitivity and elasticity of equilibria, cycles, ratios (e.g. dependency ratios, age averages and variances, temporal averages and variances, life expectancies, and population growth rates, for both age-classified and stage-classified models. Examples are presented, applying the results to both human and non-human populations.

A Model Predictive Algorithm for Active Control of Nonlinear Noise Processes

Directory of Open Access Journals (Sweden)

Qi-Zhi Zhang

2005-01-01

Full Text Available In this paper, an improved nonlinear Active Noise Control (ANC system is achieved by introducing an appropriate secondary source. For ANC system to be successfully implemented, the nonlinearity of the primary path and time delay of the secondary path must be overcome. A nonlinear Model Predictive Control (MPC strategy is introduced to deal with the time delay in the secondary path and the nonlinearity in the primary path of the ANC system. An overall online modeling technique is utilized for online secondary path and primary path estimation. The secondary path is estimated using an adaptive FIR filter, and the primary path is estimated using a Neural Network (NN. The two models are connected in parallel with the two paths. In this system, the mutual disturbances between the operation of the nonlinear ANC controller and modeling of the secondary can be greatly reduced. The coefficients of the adaptive FIR filter and weight vector of NN are adjusted online. Computer simulations are carried out to compare the proposed nonlinear MPC method with the nonlinear Filter-x Least Mean Square (FXLMS algorithm. The results showed that the convergence speed of the proposed nonlinear MPC algorithm is faster than that of nonlinear FXLMS algorithm. For testing the robust performance of the proposed nonlinear ANC system, the sudden changes in the secondary path and primary path of the ANC system are considered. Results indicated that the proposed nonlinear ANC system can rapidly track the sudden changes in the acoustic paths of the nonlinear ANC system, and ensure the adaptive algorithm stable when the nonlinear ANC system is time variable.

Phenomenological modeling of nonlinear holograms based on metallic geometric metasurfaces.

Science.gov (United States)

Ye, Weimin; Li, Xin; Liu, Juan; Zhang, Shuang

2016-10-31

Benefiting from efficient local phase and amplitude control at the subwavelength scale, metasurfaces offer a new platform for computer generated holography with high spatial resolution. Three-dimensional and high efficient holograms have been realized by metasurfaces constituted by subwavelength meta-atoms with spatially varying geometries or orientations. Metasurfaces have been recently extended to the nonlinear optical regime to generate holographic images in harmonic generation waves. Thus far, there has been no vector field simulation of nonlinear metasurface holograms because of the tremendous computational challenge in numerically calculating the collective nonlinear responses of the large number of different subwavelength meta-atoms in a hologram. Here, we propose a general phenomenological method to model nonlinear metasurface holograms based on the assumption that every meta-atom could be described by a localized nonlinear polarizability tensor. Applied to geometric nonlinear metasurfaces, we numerically model the holographic images formed by the second-harmonic waves of different spins. We show that, in contrast to the metasurface holograms operating in the linear optical regime, the wavelength of incident fundamental light should be slightly detuned from the fundamental resonant wavelength to optimize the efficiency and quality of nonlinear holographic images. The proposed modeling provides a general method to simulate nonlinear optical devices based on metallic metasurfaces.

Dissipative quantum dynamics and nonlinear sigma-model

International Nuclear Information System (INIS)

Tarasov, V.E.

1992-01-01

Sedov variational principle which is the generalization of the least action principle for the dissipative and irreversible processes and the classical dissipative mechanics in the phase space is considered. Quantum dynamics for the dissipative and irreversible processes is constructed. As an example of the dissipative quantum theory the nonlinear two-dimensional sigma-model is considered. The conformal anomaly of the energy momentum tensor trace for closed bosonic string on the affine-metric manifold is investigated. The two-loop metric beta-function for nonlinear dissipative sigma-model was calculated. The results are compared with the ultraviolet two-loop conterterms for affine-metric sigma model. 71 refs

Fertility and sexual function in female Hodgkin lymphoma survivors of reproductive age.

Science.gov (United States)

Eeltink, Corien M; Incrocci, Luca; Witte, Birgit I; Meurs, Saskia; Visser, Otto; Huijgens, Peter; Verdonck-de Leeuw, Irma M

2013-12-01

To assess the perceived fertility status and to determine the association between perceived fertility status and sexual function, as reported by young female Hodgkin lymphoma survivors. Young female Hodgkin lymphoma survivors are at risk of infertility and impaired sexual function. However, little is known about their awareness of infertility and its association with sexual functioning. A descriptive questionnaire survey. In this cross-sectional study, a survey was completed by female Hodgkin lymphoma survivors (40 years). Outcome measures included self-reported fertility status and sexual problems and the internationally validated Female Sexual Function Index. In total, 36 survivors were included (mean age 32 years, SD 4). Eighteen women (50%) thought themselves fertile. Eight survivors (22%) who perceived themselves as being infertile were more often treated with alkylator-based chemotherapy, and 63% reported sexual dysfunction. Ten survivors (28%) were not aware as to whether they were fertile or not; seven of these would like to have children. The reported fertility status was related to age and chemotherapy regimen. Regarding sexuality, 14 (39%) of the female Hodgkin lymphoma survivors reported one or more sexual problem and none reported recovery. Female sexual dysfunction according to the Female Sexual Function Index was reported by 11 (31%) survivors. Almost 30% of Hodgkin lymphoma survivors do not know whether they are fertile or not. Overall sexual dysfunction is common in Hodgkin lymphoma survivors and comparable to the general population. However, a lack of desire was significantly more often reported in female Hodgkin lymphoma survivors. To prevent assumed infertility and unintended childlessness by postponing parenthood in young female survivors, awareness of fertility status is needed. There is also a need to routinely assess sexual function and provide adequate interventions to improve arousal and lubrication problems. © 2013 John Wiley & Sons Ltd.

General Information about Childhood Hodgkin Lymphoma

Science.gov (United States)

... Reporting & Auditing Grant Transfer Grant Closeout Contracts & Small Business Training Cancer Training at NCI (Intramural) Resources for ... memory. Second cancers (new types of cancer). For female survivors of Hodgkin lymphoma, there is an increased ...

Variational Boussinesq model for strongly nonlinear dispersive waves

NARCIS (Netherlands)

Lawrence, C.; Adytia, D.; van Groesen, E.

2018-01-01

For wave tank, coastal and oceanic applications, a fully nonlinear Variational Boussinesq model with optimized dispersion is derived and a simple Finite Element implementation is described. Improving a previous weakly nonlinear version, high waves over flat and varying bottom are shown to be

Nonlinear Inertia Classification Model and Application

Directory of Open Access Journals (Sweden)

Mei Wang

2014-01-01

Full Text Available Classification model of support vector machine (SVM overcomes the problem of a big number of samples. But the kernel parameter and the punishment factor have great influence on the quality of SVM model. Particle swarm optimization (PSO is an evolutionary search algorithm based on the swarm intelligence, which is suitable for parameter optimization. Accordingly, a nonlinear inertia convergence classification model (NICCM is proposed after the nonlinear inertia convergence (NICPSO is developed in this paper. The velocity of NICPSO is firstly defined as the weighted velocity of the inertia PSO, and the inertia factor is selected to be a nonlinear function. NICPSO is used to optimize the kernel parameter and a punishment factor of SVM. Then, NICCM classifier is trained by using the optical punishment factor and the optical kernel parameter that comes from the optimal particle. Finally, NICCM is applied to the classification of the normal state and fault states of online power cable. It is experimentally proved that the iteration number for the proposed NICPSO to reach the optimal position decreases from 15 to 5 compared with PSO; the training duration is decreased by 0.0052 s and the recognition precision is increased by 4.12% compared with SVM.

Lifetime physical inactivity is associated with increased risk for Hodgkin and non-Hodgkin lymphoma: A case-control study.

Science.gov (United States)

Etter, John Lewis; Cannioto, Rikki; Soh, Kah Teong; Alquassim, Emad; Almohanna, Hani; Dunbar, Zachary; Joseph, Janine M; Balderman, Sophia; Hernandez-Ilizaliturri, Francisco; Moysich, Kirsten B

2018-03-27

Although physical activity is a well-established risk factor for several cancer types, studies evaluating its association with lymphoma have yielded inconclusive results. In such cases where physical activity is not clearly associated with cancer risk in a dose-dependent manner, investigators have begun examining physical inactivity as an independent exposure of interest. Associations of self-reported, lifetime physical inactivity with risk of developing Hodgkin lymphoma (HL) and non-Hodgkin lymphoma (NHL) were evaluated in a hospital-based case control study using data from the Patient Epidemiology Data System at Roswell Park Comprehensive Cancer Center. Participants included 87 patients with HL and 236 patients with NHL as well as 348 and 952 cancer-free controls, respectively. Multivariable-adjusted logistic regression models were fit to calculate odds ratios (OR) and 95% confidence intervals (CI) estimating the association between physical inactivity and lymphoma risk. We observed significant, positive associations between lifetime recreational physical inactivity and risk of both HL (OR = 1.90, 95% CI: 1.15-3.15) and NHL (OR = 1.35, 95% CI: 1.01-1.82). The current analysis provides evidence for a positive association between physical inactivity and risk of both HL and NHL. These results add to a growing body of research suggesting that lifetime physical inactivity may be an important independent, modifiable behavioral risk factor for cancer. Copyright © 2018 Elsevier Ltd. All rights reserved.

Nonlinear observer design for a nonlinear string/cable FEM model using contraction theory

DEFF Research Database (Denmark)

Turkyilmaz, Yilmaz; Jouffroy, Jerome; Egeland, Olav

model is presented in the form of partial differential equations (PDE). Galerkin's method is then applied to obtain a set of ordinary differential equations such that the cable model is approximated by a FEM model. Based on the FEM model, a nonlinear observer is designed to estimate the cable...

Nonlinear Modeling of the PEMFC Based On NNARX Approach

OpenAIRE

Shan-Jen Cheng; Te-Jen Chang; Kuang-Hsiung Tan; Shou-Ling Kuo

2015-01-01

Polymer Electrolyte Membrane Fuel Cell (PEMFC) is such a time-vary nonlinear dynamic system. The traditional linear modeling approach is hard to estimate structure correctly of PEMFC system. From this reason, this paper presents a nonlinear modeling of the PEMFC using Neural Network Auto-regressive model with eXogenous inputs (NNARX) approach. The multilayer perception (MLP) network is applied to evaluate the structure of the NNARX model of PEMFC. The validity and accurac...

A finite element model for nonlinear shells of revolution

International Nuclear Information System (INIS)

Cook, W.A.

1979-01-01

A shell-of-revolution model was developed to analyze impact problems associated with the safety analysis of nuclear material shipping containers. The nonlinear shell theory presented by Eric Reissner in 1972 was used to develop our model. Reissner's approach includes transverse shear deformation and moments turning about the middle surface normal. With these features, this approach is valid for both thin and thick shells. His theory is formulated in terms of strain and stress resultants that refer to the undeformed geometry. This nonlinear shell model is developed using the virtual work principle associated with Reissner's equilibrium equations. First, the virtual work principle is modified for incremental loading; then it is linearized by assuming that the nonlinear portions of the strains are known. By iteration, equilibrium is then approximated for each increment. A benefit of this approach is that this iteration process makes it possible to use nonlinear material properties. (orig.)

Heeding the waveform inversion nonlinearity by unwrapping the model and data

KAUST Repository

Alkhalifah, Tariq Ali

2012-01-01

Unlike traveltime inversion, waveform inversion provides relatively higher-resolution inverted models. This feature, however, comes at the cost of introducing complex nonlinearity to the inversion operator complicating the convergence process. We use unwrapped-phase-based objective functions to reduce such nonlinearity in a domain in which the high-frequency component is given by the traveltime inversion. Such information is packaged in a frequency-dependent attribute (or traveltime) that can be easily manipulated at different frequencies. It unwraps the phase of the wavefield yielding far less nonlinearity in the objective function than those experienced with the conventional misfit objective function, and yet it still holds most of the critical waveform information in its frequency dependency. However, it suffers from nonlinearity introduced by the model (or reflectivity), as events interact with each other (something like cross talk). This stems from the sinusoidal nature of the band-limited reflectivity model. Unwrapping the phase for such a model can mitigate this nonlinearity as well. Specifically, a simple modification to the inverted domain (or model), can reduce the effect of the model-induced nonlinearity and, thus, make the inversion more convergent. Simple examples are used to highlight such features.

Estimation of Nonlinear DC-Motor Models Using a Sensitivity Approach

DEFF Research Database (Denmark)

Knudsen, Morten; Jensen, J.G.

1995-01-01

A nonlinear model structure for a permanent magnet DC-motor, appropriate for simulation and controller design, is developed.......A nonlinear model structure for a permanent magnet DC-motor, appropriate for simulation and controller design, is developed....

Parameter Estimation and Prediction of a Nonlinear Storage Model: an algebraic approach

NARCIS (Netherlands)

Doeswijk, T.G.; Keesman, K.J.

2005-01-01

Generally, parameters that are nonlinear in system models are estimated by nonlinear least-squares optimization algorithms. In this paper, if a nonlinear discrete-time model with a polynomial quotient structure in input, output, and parameters, a method is proposed to re-parameterize the model such

Comments on Nonlinear Sigma Models Coupled to Supergravity arXiv

CERN Document Server

Ferrara, Sergio

2017-12-10

N=1 , D=4 nonlinear sigma models, parametrized by chiral superfields, usually describe Kählerian geometries, provided that Einstein frame supergravity is used. The sigma model metric is no longer Kähler when local supersymmetry becomes nonlinearly realized through the nilpotency of the supergravity auxiliary fields. In some cases the nonlinear realization eliminates one scalar propagating degree of freedom. This happens when the sigma model conformal-frame metric has co-rank 2. In the geometry of the inflaton, this effect eliminates its scalar superpartner. We show that the sigma model metric remains semidefinite positive in all cases, due the to positivity properties of the conformal-frame sigma model metric.

Nonlinear Model Predictive Control for Solid Oxide Fuel Cell System Based On Wiener Model

OpenAIRE

T. H. Lee; J. H. Park; S. M. Lee; S. C. Lee

2010-01-01

In this paper, we consider Wiener nonlinear model for solid oxide fuel cell (SOFC). The Wiener model of the SOFC consists of a linear dynamic block and a static output non-linearity followed by the block, in which linear part is approximated by state-space model and the nonlinear part is identified by a polynomial form. To control the SOFC system, we have to consider various view points such as operating conditions, another constraint conditions, change of load current and so on. A change of ...

Lukasiewicz-Topos Models of Neural Networks, Cell Genome and Interactome Nonlinear Dynamic Models

CERN Document Server

Baianu, I C

2004-01-01

A categorical and Lukasiewicz-Topos framework for Lukasiewicz Algebraic Logic models of nonlinear dynamics in complex functional systems such as neural networks, genomes and cell interactomes is proposed. Lukasiewicz Algebraic Logic models of genetic networks and signaling pathways in cells are formulated in terms of nonlinear dynamic systems with n-state components that allow for the generalization of previous logical models of both genetic activities and neural networks. An algebraic formulation of variable 'next-state functions' is extended to a Lukasiewicz Topos with an n-valued Lukasiewicz Algebraic Logic subobject classifier description that represents non-random and nonlinear network activities as well as their transformations in developmental processes and carcinogenesis.

Fertility and sexual function in female Hodgkin lymphoma survivors of reproductive age

NARCIS (Netherlands)

Eeltink, C.M.; Incrocci, L.; Witte, B.I.; Meurs, S.; Visser, O.; Huijgens, P.C.; de Leeuw, I.M.

2013-01-01

Aims and objectives: To assess the perceived fertility status and to determine the association between perceived fertility status and sexual function, as reported by young female Hodgkin lymphoma survivors. Background: Young female Hodgkin lymphoma survivors are at risk of infertility and impaired

Nonlinear control of the Salnikov model reaction

DEFF Research Database (Denmark)

Recke, Bodil; Jørgensen, Sten Bay

1999-01-01

This paper explores different nonlinear control schemes, applied to a simple model reaction. The model is the Salnikov model, consisting of two ordinary differential equations. The control strategies investigated are I/O-linearisation, Exact linearisation, exact linearisation combined with LQR...

ONC201 induces cell death in pediatric non-Hodgkin's lymphoma cells

OpenAIRE

Talekar, Mala K; Allen, Joshua E; Dicker, David T; El-Deiry, Wafik S

2015-01-01

ONC201/TIC10 is a small molecule initially discovered by its ability to coordinately induce and activate the TRAIL pathway selectively in tumor cells and has recently entered clinical trials in adult advanced cancers. The anti-tumor activity of ONC201 has previously been demonstrated in several preclinical models of cancer, including refractory solid tumors and a transgenic lymphoma mouse model. Based on the need for new safe and effective therapies in pediatric non-Hodgkin's lymphoma (NHL) a...

Modeling Autoregressive Processes with Moving-Quantiles-Implied Nonlinearity

Directory of Open Access Journals (Sweden)

Isao Ishida

2015-01-01

Full Text Available We introduce and investigate some properties of a class of nonlinear time series models based on the moving sample quantiles in the autoregressive data generating process. We derive a test fit to detect this type of nonlinearity. Using the daily realized volatility data of Standard & Poor’s 500 (S&P 500 and several other indices, we obtained good performance using these models in an out-of-sample forecasting exercise compared with the forecasts obtained based on the usual linear heterogeneous autoregressive and other models of realized volatility.

Modelling Loudspeaker Non-Linearities

DEFF Research Database (Denmark)

Agerkvist, Finn T.

2007-01-01

This paper investigates different techniques for modelling the non-linear parameters of the electrodynamic loudspeaker. The methods are tested not only for their accuracy within the range of original data, but also for the ability to work reasonable outside that range, and it is demonstrated...... that polynomial expansions are rather poor at this, whereas an inverse polynomial expansion or localized fitting functions such as the gaussian are better suited for modelling the Bl-factor and compliance. For the inductance the sigmoid function is shown to give very good results. Finally the time varying...

Characteristics of lymphographic semiotics in children with Hodgkin's disease

International Nuclear Information System (INIS)

Baryshnikov, V.L.; Krivenko, Eh.V.; Minkh, N.V.

1984-01-01

Direct low lymphography was performed in 140 children aged 2.5 to 16 wheh Hodgkin's disease. Typical changes in the lymph nodes were found in 45 (32.14%) patient;. Symptoms of disordered drainage function of the nodes in children occur more frequently than in adults (in 71% of the cases observed). X.ray signs of the morphological changes in the lymph nodes that in combination with functional symptoms give 4 main symptomocomplexes which are characteristic of Hodgkin's disease in children are singled out

Nonlinear Modelling of Low Frequency Loudspeakers

DEFF Research Database (Denmark)

Olsen, Erling Sandermann

1997-01-01

In the Danish LoDist project on distortion from dynamic low frequency loudspeakers a detailed nonlinear model of loudspeakers has been developed. The model has been implemented in a PC program so that it can be used to create signals for listening tests and analysis. Also, different methods...

Nonlinear Modelling of Low Frequency Loudspeakers

DEFF Research Database (Denmark)

Olsen, Erling Sandermann

1997-01-01

In the Danish LoDist project on distortion from dynamic low-frequency loudspeakers, a detailed nonlinear model of loudspeakers has been developed. The model has been implemented in a PC program so that it can be used to create signals for listening tests and analysis. Also, different methods...

Thermoviscous Model Equations in Nonlinear Acoustics

DEFF Research Database (Denmark)

Rasmussen, Anders Rønne

Four nonlinear acoustical wave equations that apply to both perfect gasses and arbitrary fluids with a quadratic equation of state are studied. Shock and rarefaction wave solutions to the equations are studied. In order to assess the accuracy of the wave equations, their solutions are compared...... to solutions of the basic equations from which the wave equations are derived. A straightforward weakly nonlinear equation is the most accurate for shock modeling. A higher order wave equation is the most accurate for modeling of smooth disturbances. Investigations of the linear stability properties...... of solutions to the wave equations, reveal that the solutions may become unstable. Such instabilities are not found in the basic equations. Interacting shocks and standing shocks are investigated....

A simple numerical model of a geometrically nonlinear Timoshenko beam

NARCIS (Netherlands)

Keijdener, C.; Metrikine, A.

2015-01-01

In the original problem for which this model was developed, onedimensional flexible objects interact through a non-linear contact model. Due to the non-linear nature of the contact model, a numerical time-domain approach was adopted. One of the goals was to see if the coupling between axial and

Development of an Integrated Nonlinear Aeroservoelastic Flight Dynamic Model of the NASA Generic Transport Model

Science.gov (United States)

Nguyen, Nhan; Ting, Eric

2018-01-01

This paper describes a recent development of an integrated fully coupled aeroservoelastic flight dynamic model of the NASA Generic Transport Model (GTM). The integrated model couples nonlinear flight dynamics to a nonlinear aeroelastic model of the GTM. The nonlinearity includes the coupling of the rigid-body aircraft states in the partial derivatives of the aeroelastic angle of attack. Aeroservoelastic modeling of the control surfaces which are modeled by the Variable Camber Continuous Trailing Edge Flap is also conducted. The R.T. Jones' method is implemented to approximate unsteady aerodynamics. Simulations of the GTM are conducted with simulated continuous and discrete gust loads..

Non-Hodgkin's lymphoma - the role of radiation therapy

International Nuclear Information System (INIS)

Gospodarowicz, Mary K.

1995-01-01

Objective: To review the approach to the diagnosis, assessment, treatment and continuing management of patients with Non-Hodgkin's lymphoma with the emphasis on the role of radiation therapy in this group of diseases. The entity of 'Non-Hodgkin's Lymphoma' encompasses a diverse group of disorders involving almost any part of the body. This diversity bedevils any attempt to unify the approach to this disease on a rational basis. Nevertheless, some broad principles can be applied to almost any presentation of Non-Hodgkin's lymphoma. The approach to the management of Non-Hodgkin's lymphoma is based on the histologic type, localization and extent of disease and other disease and patient related prognostic factors. The accurate pathologic diagnosis of lymphoma has been greatly facilitated by availability of markers, molecular and genetic techniques. The newly proposed revised classification of lymphomas and its impact on these of RT will be discussed. Although the Ann Arbor staging classification has been shown to provide important prognostic information, other factors have equivalent, if not greater, influence on outcome in patients with Non-Hodgkin's lymphomas. The management of lymphomas is based primarily on the histologic type and extent of the disease including stage, tumour bulk, number of sites involved and location of the disease. The success of curative radiation therapy is contingent upon the presence of localized disease, normal tissue tolerance allowing the delivery of RT curative dose (30-35 Gy) and the tumour bulk. The current evidence suggests that locoregional RT for stage I and II low grade lymphoma results in approximately 50% prolonged (10-15 years) failure free rate and possible cure. Radiation alone is no longer used for intermediate and high grade lymphomas. The standard management of stage I and II intermediate grade large cell and mixed lymphomas is with doxorubicin based chemotherapy (e.g. CHOP) followed by involved field radiation. The

Modeling and non-linear responses of MEMS capacitive accelerometer

Directory of Open Access Journals (Sweden)

Sri Harsha C.

2014-01-01

Full Text Available A theoretical investigation of an electrically actuated beam has been illustrated when the electrostatic-ally actuated micro-cantilever beam is separated from the electrode by a moderately large gap for two distinct types of geometric configurations of MEMS accelerometer. Higher order nonlinear terms have been taken into account for studying the pull in voltage analysis. A nonlinear model of gas film squeezing damping, another source of nonlinearity in MEMS devices is included in obtaining the dynamic responses. Moreover, in the present work, the possible source of nonlinearities while formulating the mathematical model of a MEMS accelerometer and their influences on the dynamic responses have been investigated. The theoretical results obtained by using MATLAB has been verified with the results obtained in FE software and has been found in good agreement. Criterion towards stable micro size accelerometer for each configuration has been investigated. This investigation clearly provides an understanding of nonlinear static and dynamics characteristics of electrostatically micro cantilever based device in MEMS.

Non-Hodgkin's lymphoma presenting as a single liver mass; Linfoma nao-Hodgkin apresentando-se como massa hepatica unica

Energy Technology Data Exchange (ETDEWEB)

Peixoto, Mila Correia Gois; Peixoto Filho, Anibal Araujo Alves; D' Ippolito, Giuseppe [Hospital Sao Luiz, Sao Paulo, SP (Brazil). Setor de US/TC/RM]. E-mail: scoposl@uol.com.br; Ribeiro, Alessandra Caivano Rodrigues [Hospital Sao Luiz, Sao Paulo, SP (Brazil). Setor de Diagnostico por Imagem

2009-01-15

Objective: to describe the main imaging findings of non-Hodgkin's lymphoma presenting as a single liver mass. Materials and methods: a retrospective study was developed with analysis of cases where a single liver mass was observed at ultrasonography, computed tomography and magnetic resonance imaging, and histologically diagnosed as non-Hodgkin's lymphoma. The studies were reviewed by two observers in consensus. Results: three male patients in the fifth decade of life, with non-specific clinical manifestations and single liver mass diagnosed as non-Hodgkin's lymphoma were identified. A hepatic lesion with target sign was observed at ultrasonography in all of the cases. At computed tomography, all the patients presented a heterogeneous, hypodense mass with a ring enhancement. At magnetic resonance imaging, the lesions were heterogeneous and hypointense on T1-weighted and hyperintense on T2-weighted images. Additionally, a ring enhancement was observed in all of the cases after contrast injection. At the moment of the diagnosis, none of the patients presented lymphadenomegaly or involvement of other solid viscera. Conclusion: the diagnosis of hepatic lymphoma should be considered in the presence of a ring-enhanced single liver mass. (author)

Novel insights in the pathogenesis of Hodgkin lymphoma : microenvironment, genetic landscape and regulation of HLA expression

NARCIS (Netherlands)

Liu, Yuxuan

2013-01-01

Gemuteerde genen spelen belangrijke rol in ontstaan Hodgkin lymfoom Het klassieke Hodgkin lymfoom (eerder bekend als ‘de ziekte van Hodgkin’) bestaat voor slechts een zeer klein deel uit tumorcellen en voor het overgrote deel uit normale immuuncellen. Die samenstelling maakt het Hodgkin lymfoom

Simplified Model of Nonlinear Landau Damping

International Nuclear Information System (INIS)

Yampolsky, N.A.; Fisch, N.J.

2009-01-01

The nonlinear interaction of a plasma wave with resonant electrons results in a plateau in the electron distribution function close to the phase velocity of the plasma wave. As a result, Landau damping of the plasma wave vanishes and the resonant frequency of the plasma wave downshifts. However, this simple picture is invalid when the external driving force changes the plasma wave fast enough so that the plateau cannot be fully developed. A new model to describe amplification of the plasma wave including the saturation of Landau damping and the nonlinear frequency shift is proposed. The proposed model takes into account the change of the plasma wave amplitude and describes saturation of the Landau damping rate in terms of a single fluid equation, which simplifies the description of the inherently kinetic nature of Landau damping. A proposed fluid model, incorporating these simplifications, is verified numerically using a kinetic Vlasov code.

Effects of radiochemotherapy and splenectomy on cellular immunity in long-term survivors of Hodgkin's disease and non-Hodgkin's lymphoma

International Nuclear Information System (INIS)

Steele, R.; Han, T.

1978-01-01

Thirty-six patients treated for Hodgkin's disease (HD) or non-Hodgkin's lymphoma (NHL) who had been in complete remission and off all therapy for greater than two years were examined for evidence of immunosuppression. All patients were found to have marked depression of their lymphocyte blastogenic response to phytohemagglutinin (PHA) and of their skin test responses. No abnormalities of serum protein or immunoglobulins were found. T cells were significantly lower than normal in patients who had had Hodgkin's disease, but not in those who had had NHL. B cells, on the other hand, were significantly elevated in both groups. Splenectomy elevated the total lymphocyte count, while those who had not had a splenectomy had lower than normal lymphocyte counts. B cells were elevated while T cells tended to be lower in both splenectomy and nonsplenectomy groups, though only in the nonsplenectomized patients did this reach statistical significance. The PHA response tended to be higher in patients with less advanced disease and less extensive treatment than in those with more advanced disease and more extensive treatment, although there was no statistically significant difference. Skin test response though, was shown to correlate well with both stage of disease at diagnosis and extent of treatment

Modelization of highly nonlinear waves in coastal regions

Science.gov (United States)

Gouin, Maïté; Ducrozet, Guillaume; Ferrant, Pierre

2015-04-01

The proposed work deals with the development of a highly non-linear model for water wave propagation in coastal regions. The accurate modelization of surface gravity waves is of major interest in ocean engineering, especially in the field of marine renewable energy. These marine structures are intended to be settled in coastal regions where the effect of variable bathymetry may be significant on local wave conditions. This study presents a numerical model for the wave propagation with complex bathymetry. It is based on High-Order Spectral (HOS) method, initially limited to the propagation of non-linear wave fields over flat bottom. Such a model has been developed and validated at the LHEEA Lab. (Ecole Centrale Nantes) over the past few years and the current developments will enlarge its application range. This new numerical model will keep the interesting numerical properties of the original pseudo-spectral approach (convergence, efficiency with the use of FFTs, …) and enable the possibility to propagate highly non-linear wave fields over long time and large distance. Different validations will be provided in addition to the presentation of the method. At first, Bragg reflection will be studied with the proposed approach. If the Bragg condition is satisfied, the reflected wave generated by a sinusoidal bottom patch should be amplified as a result of resonant quadratic interactions between incident wave and bottom. Comparisons will be provided with experiments and reference solutions. Then, the method will be used to consider the transformation of a non-linear monochromatic wave as it propagates up and over a submerged bar. As the waves travel up the front slope of the bar, it steepens and high harmonics are generated due to non-linear interactions. Comparisons with experimental data will be provided. The different test cases will assess the accuracy and efficiency of the method proposed.

Weak noise in neurons may powerfully inhibit the generation of repetitive spiking but not its propagation.

Directory of Open Access Journals (Sweden)

Henry C Tuckwell

2010-05-01

Full Text Available Many neurons have epochs in which they fire action potentials in an approximately periodic fashion. To see what effects noise of relatively small amplitude has on such repetitive activity we recently examined the response of the Hodgkin-Huxley (HH space-clamped system to such noise as the mean and variance of the applied current vary, near the bifurcation to periodic firing. This article is concerned with a more realistic neuron model which includes spatial extent. Employing the Hodgkin-Huxley partial differential equation system, the deterministic component of the input current is restricted to a small segment whereas the stochastic component extends over a region which may or may not overlap the deterministic component. For mean values below, near and above the critical values for repetitive spiking, the effects of weak noise of increasing strength is ascertained by simulation. As in the point model, small amplitude noise near the critical value dampens the spiking activity and leads to a minimum as noise level increases. This was the case for both additive noise and conductance-based noise. Uniform noise along the whole neuron is only marginally more effective in silencing the cell than noise which occurs near the region of excitation. In fact it is found that if signal and noise overlap in spatial extent, then weak noise may inhibit spiking. If, however, signal and noise are applied on disjoint intervals, then the noise has no effect on the spiking activity, no matter how large its region of application, though the trajectories are naturally altered slightly by noise. Such effects could not be discerned in a point model and are important for real neuron behavior. Interference with the spike train does nevertheless occur when the noise amplitude is larger, even when noise and signal do not overlap, being due to the instigation of secondary noise-induced wave phenomena rather than switching the system from one attractor (firing regularly to

Finite element modeling of nonlinear piezoelectric energy harvesters with magnetic interaction

International Nuclear Information System (INIS)

Upadrashta, Deepesh; Yang, Yaowen

2015-01-01

Piezoelectric energy harvesting from ambient vibrations is a potential technology for powering wireless sensors and low power electronic devices. The conventional linear harvesters suffer from narrow operational bandwidth. Many attempts have been made especially using the magnetic interaction to broaden the bandwidth of harvesters. The finite element (FE) modeling has been used only for analyzing the linear harvesters in the literature. The main difficulties in extending the FE modeling to analyze the nonlinear harvesters involving magnetic interaction are developing the mesh needed for magnetic interaction in dynamic problems and the high demand on computational resource needed for solving the coupled electrical–mechanical–magnetic problem. In this paper, an innovative method is proposed to model the magnetic interaction without inclusion of the magnetic module. The magnetic force is modeled using the nonlinear spring element available in ANSYS finite element analysis (FEA) package, thus simplifying the simulation of nonlinear piezoelectric energy harvesters as an electromechanically coupled problem. Firstly, an FE model of a monostable nonlinear harvester with cantilever configuration is developed and the results are validated with predictions from the theoretical model. Later, the proposed technique of FE modeling is extended to a complex 2-degree of freedom nonlinear energy harvester for which an accurate analytical model is difficult to derive. The performance predictions from FEA are compared with the experimental results. It is concluded that the proposed modeling technique is able to accurately analyze the behavior of nonlinear harvesters with magnetic interaction. (paper)

Nonlinear Prediction Model for Hydrologic Time Series Based on Wavelet Decomposition

Science.gov (United States)

Kwon, H.; Khalil, A.; Brown, C.; Lall, U.; Ahn, H.; Moon, Y.

2005-12-01

Traditionally forecasting and characterizations of hydrologic systems is performed utilizing many techniques. Stochastic linear methods such as AR and ARIMA and nonlinear ones such as statistical learning theory based tools have been extensively used. The common difficulty to all methods is the determination of sufficient and necessary information and predictors for a successful prediction. Relationships between hydrologic variables are often highly nonlinear and interrelated across the temporal scale. A new hybrid approach is proposed for the simulation of hydrologic time series combining both the wavelet transform and the nonlinear model. The present model employs some merits of wavelet transform and nonlinear time series model. The Wavelet Transform is adopted to decompose a hydrologic nonlinear process into a set of mono-component signals, which are simulated by nonlinear model. The hybrid methodology is formulated in a manner to improve the accuracy of a long term forecasting. The proposed hybrid model yields much better results in terms of capturing and reproducing the time-frequency properties of the system at hand. Prediction results are promising when compared to traditional univariate time series models. An application of the plausibility of the proposed methodology is provided and the results conclude that wavelet based time series model can be utilized for simulating and forecasting of hydrologic variable reasonably well. This will ultimately serve the purpose of integrated water resources planning and management.

Development of nonperturbative nonlinear optics models including effects of high order nonlinearities and of free electron plasma: Maxwell–Schrödinger equations coupled with evolution equations for polarization effects, and the SFA-like nonlinear optics model

International Nuclear Information System (INIS)

Lorin, E; Bandrauk, A D; Lytova, M; Memarian, A

2015-01-01

This paper is dedicated to the exploration of non-conventional nonlinear optics models for intense and short electromagnetic fields propagating in a gas. When an intense field interacts with a gas, usual nonlinear optics models, such as cubic nonlinear Maxwell, wave and Schrödinger equations, derived by perturbation theory may become inaccurate or even irrelevant. As a consequence, and to include in particular the effect of free electrons generated by laser–molecule interaction, several heuristic models, such as UPPE, HOKE models, etc, coupled with Drude-like models [1, 2], were derived. The goal of this paper is to present alternative approaches based on non-heuristic principles. This work is in particular motivated by the on-going debate in the filamentation community, about the effect of high order nonlinearities versus plasma effects due to free electrons, in pulse defocusing occurring in laser filaments [3–9]. The motivation of our work goes beyond filamentation modeling, and is more generally related to the interaction of any external intense and (short) pulse with a gas. In this paper, two different strategies are developed. The first one is based on the derivation of an evolution equation on the polarization, in order to determine the response of the medium (polarization) subject to a short and intense electromagnetic field. Then, we derive a combined semi-heuristic model, based on Lewenstein’s strong field approximation model and the usual perturbative modeling in nonlinear optics. The proposed model allows for inclusion of high order nonlinearities as well as free electron plasma effects. (paper)

Effect of P T symmetry on nonlinear waves for three-wave interaction models in the quadratic nonlinear media

Science.gov (United States)

Shen, Yujia; Wen, Zichao; Yan, Zhenya; Hang, Chao

2018-04-01

We study the three-wave interaction that couples an electromagnetic pump wave to two frequency down-converted daughter waves in a quadratic optical crystal and P T -symmetric potentials. P T symmetric potentials are shown to modulate stably nonlinear modes in two kinds of three-wave interaction models. The first one is a spatially extended three-wave interaction system with odd gain-and-loss distribution in the channel. Modulated by the P T -symmetric single-well or multi-well Scarf-II potentials, the system is numerically shown to possess stable soliton solutions. Via adiabatical change of system parameters, numerical simulations for the excitation and evolution of nonlinear modes are also performed. The second one is a combination of P T -symmetric models which are coupled via three-wave interactions. Families of nonlinear modes are found with some particular choices of parameters. Stable and unstable nonlinear modes are shown in distinct families by means of numerical simulations. These results will be useful to further investigate nonlinear modes in three-wave interaction models.

Nonlinear Model Predictive Control with Constraint Satisfactions for a Quadcopter

Science.gov (United States)

Wang, Ye; Ramirez-Jaime, Andres; Xu, Feng; Puig, Vicenç

2017-01-01

This paper presents a nonlinear model predictive control (NMPC) strategy combined with constraint satisfactions for a quadcopter. The full dynamics of the quadcopter describing the attitude and position are nonlinear, which are quite sensitive to changes of inputs and disturbances. By means of constraint satisfactions, partial nonlinearities and modeling errors of the control-oriented model of full dynamics can be transformed into the inequality constraints. Subsequently, the quadcopter can be controlled by an NMPC controller with the updated constraints generated by constraint satisfactions. Finally, the simulation results applied to a quadcopter simulator are provided to show the effectiveness of the proposed strategy.

Nonlinear Fuzzy Model Predictive Control for a PWR Nuclear Power Plant

Directory of Open Access Journals (Sweden)

Xiangjie Liu

2014-01-01

Full Text Available Reliable power and temperature control in pressurized water reactor (PWR nuclear power plant is necessary to guarantee high efficiency and plant safety. Since the nuclear plants are quite nonlinear, the paper presents nonlinear fuzzy model predictive control (MPC, by incorporating the realistic constraints, to realize the plant optimization. T-S fuzzy modeling on nuclear power plant is utilized to approximate the nonlinear plant, based on which the nonlinear MPC controller is devised via parallel distributed compensation (PDC scheme in order to solve the nonlinear constraint optimization problem. Improved performance compared to the traditional PID controller for a TMI-type PWR is obtained in the simulation.

COMBINING LONG MEMORY AND NONLINEAR MODEL OUTPUTS FOR INFLATION FORECAST

OpenAIRE

Heri Kuswanto; Irhamah Alimuhajin; Laylia Afidah

2014-01-01

Long memory and nonlinearity have been proven as two models that are easily to be mistaken. In other words, nonlinearity is a strong candidate of spurious long memory by introducing a certain degree of fractional integration that lies in the region of long memory. Indeed, nonlinear process belongs to short memory with zero integration order. The idea of the forecast is to obtain the future condition with minimum error. Some researches argued that no matter what the model is, the important thi...

Nonlinear friction model for servo press simulation

Science.gov (United States)

Ma, Ninshu; Sugitomo, Nobuhiko; Kyuno, Takunori; Tamura, Shintaro; Naka, Tetsuo

2013-12-01

The friction coefficient was measured under an idealized condition for a pulse servo motion. The measured friction coefficient and its changing with both sliding distance and a pulse motion showed that the friction resistance can be reduced due to the re-lubrication during unloading process of the pulse servo motion. Based on the measured friction coefficient and its changes with sliding distance and re-lubrication of oil, a nonlinear friction model was developed. Using the newly developed the nonlinear friction model, a deep draw simulation was performed and the formability was evaluated. The results were compared with experimental ones and the effectiveness was verified.

Mathematical models for suspension bridges nonlinear structural instability

CERN Document Server

Gazzola, Filippo

2015-01-01

This work provides a detailed and up-to-the-minute survey of the various stability problems that can affect suspension bridges. In order to deduce some experimental data and rules on the behavior of suspension bridges, a number of historical events are first described, in the course of which several questions concerning their stability naturally arise. The book then surveys conventional mathematical models for suspension bridges and suggests new nonlinear alternatives, which can potentially supply answers to some stability questions. New explanations are also provided, based on the nonlinear structural behavior of bridges. All the models and responses presented in the book employ the theory of differential equations and dynamical systems in the broader sense, demonstrating that methods from nonlinear analysis can allow us to determine the thresholds of instability.

An Improved Nonlinear Five-Point Model for Photovoltaic Modules

Directory of Open Access Journals (Sweden)

Sakaros Bogning Dongue

2013-01-01

Full Text Available This paper presents an improved nonlinear five-point model capable of analytically describing the electrical behaviors of a photovoltaic module for each generic operating condition of temperature and solar irradiance. The models used to replicate the electrical behaviors of operating PV modules are usually based on some simplified assumptions which provide convenient mathematical model which can be used in conventional simulation tools. Unfortunately, these assumptions cause some inaccuracies, and hence unrealistic economic returns are predicted. As an alternative, we used the advantages of a nonlinear analytical five-point model to take into account the nonideal diode effects and nonlinear effects generally ignored, which PV modules operation depends on. To verify the capability of our method to fit PV panel characteristics, the procedure was tested on three different panels. Results were compared with the data issued by manufacturers and with the results obtained using the five-parameter model proposed by other authors.

Modelling of a bridge-shaped nonlinear piezoelectric energy harvester

International Nuclear Information System (INIS)

Gafforelli, G; Corigliano, A; Xu, R; Kim, S G

2013-01-01

Piezoelectric MicroElectroMechanical Systems (MEMS) energy harvesting is an attractive technology for harvesting small magnitudes of energy from ambient vibrations. Increasing the operating frequency bandwidth of such devices is one of the major issues for real world applications. A MEMS-scale doubly clamped nonlinear beam resonator is designed and developed to demonstrate very wide bandwidth and high power density. In this paper a first complete theoretical discussion of nonlinear resonating piezoelectric energy harvesting is provided. The sectional behaviour of the beam is studied through the Classical Lamination Theory (CLT) specifically modified to introduce the piezoelectric coupling and nonlinear Green-Lagrange strain tensor. A lumped parameter model is built through Rayleigh-Ritz Method and the resulting nonlinear coupled equations are solved in the frequency domain through the Harmonic Balance Method (HBM). Finally, the influence of external load resistance on the dynamic behaviour is studied. The theoretical model shows that nonlinear resonant harvesters have much wider power bandwidth than that of linear resonators but their maximum power is still bounded by the mechanical damping as is the case for linear resonating harvesters

[Hodgkin and non-Hodgkin lymphoma of adolescents and young adults].

Science.gov (United States)

Garciaz, Sylvain; Coso, Diane; Brice, Pauline; Bouabdallah, Réda

2016-12-01

Lymphoma is one of the most frequent cancers in adolescent and young adults. Hodgkin Lymphoma is curable in more than 90% of cases. Recent pediatric and adults protocols aimed to decrease long term toxicities (mostly gonadic and cardiovascular) and secondary malignancies, reducing the use of alkylating agents and limiting radiation fields. Risk-adapted strategies, using positron emission tomography staging, are about to become a standard, both in adult and pediatric protocols. These approaches allow obtaining excellent results in adolescents with Hodgkin lymphoma. On the other hand, treatment of adolescents with diffuse large B-cell lymphoma raises some questions. Even through children have good outcomes when treated with risk-adapted strategies, adolescents who are between 15 and 18 years old seem to experience poorer survivals, whereas patients older than 18 years old have globally the same outcome than older adults. This category of patient needs a particular care, based on a tight coordination between adults and pediatric oncologists. Primary mediastinal lymphomas, a subtype of BLDCL frequent in young adult population, exhibits poorer outcomes in children or young adolescent population than in older ones. Taking together, B-cell lymphoma benefited from recent advances in immunotherapy (in particular with the extended utilization of rituximab) and metabolic response-adapted strategies. In conclusion, adolescent and young adult's lymphomas are very curable diseases but require a personalized management in onco-hematological units. Copyright © 2016 Société Française du Cancer. Published by Elsevier Masson SAS. All rights reserved.

Association of Hodgkin's lymphoma with Epstein Barr virus infection

Directory of Open Access Journals (Sweden)

Elmir Čičkušić

2007-02-01

Full Text Available The role of Epstein Barr virus (EBV in the onset of Hodgkin's lymphoma has been a subject of ongoing research. However, confirmation of EBV oncogenic involvement was not possible due to the small number of neoplastic cells characteristic for this type of tumor. Presence of EBV infection in neoplastic and non-neoplastic cells was analyzed in 81 cases of Hodgkin's lymphoma. In neoplastic cells, using an immunohistochemical method, latent membrane protein 1 (LMP1 was found in 33,3% of cases, while in situ hybridization results demonstrated the presence of EBER RNA in 48,1% of the cases. EBER RNA was found in non-neoplastic lymphocytes in 38,3% of cases. EBV is most frequently associated with Hodgkin's lymphoma in the first and seventh decade of life, specifically the nodular sclerosis subtype. No apparent difference was observed in the association of Hodgkin's lymphoma with EBV between genders, or in relation to clinical stage of the disease and average age of the patient. However, association with childhood age is significantly greater in comparison to adults. EBV associated disease shows a significantly greater prevalence in T lymphocytes. Slightly more abundant are cytotoxic T lymphocytes, which are also more frequently in contact with Reed-Sternberg cells, although there is no difference in number and positioning of histiocytes. Variations between the data on the association of EBV with Hodgkin's lymphoma among studies from different parts of the world suggest that factors of age, gender, ethnic background and social status might present biological modifiers of EBV influence on the pathogenesis of this neoplasm. The differences in non-neoplastic infiltrate EBV+ and EBV- lymphoma indicate the effect of the virus on the immune interaction of tumor and host in this disease.

Fast and local non-linear evolution of steep wave-groups on deep water: A comparison of approximate models to fully non-linear simulations

International Nuclear Information System (INIS)

Adcock, T. A. A.; Taylor, P. H.

2016-01-01

The non-linear Schrödinger equation and its higher order extensions are routinely used for analysis of extreme ocean waves. This paper compares the evolution of individual wave-packets modelled using non-linear Schrödinger type equations with packets modelled using fully non-linear potential flow models. The modified non-linear Schrödinger Equation accurately models the relatively large scale non-linear changes to the shape of wave-groups, with a dramatic contraction of the group along the mean propagation direction and a corresponding extension of the width of the wave-crests. In addition, as extreme wave form, there is a local non-linear contraction of the wave-group around the crest which leads to a localised broadening of the wave spectrum which the bandwidth limited non-linear Schrödinger Equations struggle to capture. This limitation occurs for waves of moderate steepness and a narrow underlying spectrum

Immuno phenotype of blood lymphocytes in radiation-associated Hodgkin's disease

International Nuclear Information System (INIS)

Butenko, A.K.

2000-01-01

Immuno phenotype of peripheral blood lymphocytes has been studied in Hodgkin's disease including patients exposed to radionuclides of the characteristic Chernobyl pattern. The group of patients under study has been characterized by decreasing T- and NK-cell immunity, such a decrease being more pronounced in radiation-associated Hodgkin's lymphoma. The data obtained as well as the evidence of Epstein-Barr virus activation could explain the aggressiveness of the disease in such patients and the difficulties in their treatment

Spatiotemporal drought forecasting using nonlinear models

Science.gov (United States)

Vasiliades, Lampros; Loukas, Athanasios

2010-05-01

Spatiotemporal data mining is the extraction of unknown and implicit knowledge, structures, spatiotemporal relationships, or patterns not explicitly stored in spatiotemporal databases. As one of data mining techniques, forecasting is widely used to predict the unknown future based upon the patterns hidden in the current and past data. In order to achieve spatiotemporal forecasting, some mature analysis tools, e.g., time series and spatial statistics are extended to the spatial dimension and the temporal dimension, respectively. Drought forecasting plays an important role in the planning and management of natural resources and water resource systems in a river basin. Early and timelines forecasting of a drought event can help to take proactive measures and set out drought mitigation strategies to alleviate the impacts of drought. Despite the widespread application of nonlinear mathematical models, comparative studies on spatiotemporal drought forecasting using different models are still a huge task for modellers. This study uses a promising approach, the Gamma Test (GT), to select the input variables and the training data length, so that the trial and error workload could be greatly reduced. The GT enables to quickly evaluate and estimate the best mean squared error that can be achieved by a smooth model on any unseen data for a given selection of inputs, prior to model construction. The GT is applied to forecast droughts using monthly Standardized Precipitation Index (SPI) timeseries at multiple timescales in several precipitation stations at Pinios river basin in Thessaly region, Greece. Several nonlinear models have been developed efficiently, with the aid of the GT, for 1-month up to 12-month ahead forecasting. Several temporal and spatial statistical indices were considered for the performance evaluation of the models. The predicted results show reasonably good agreement with the actual data for short lead times, whereas the forecasting accuracy decreases with

Nonlinear adaptive inverse control via the unified model neural network

Science.gov (United States)

Jeng, Jin-Tsong; Lee, Tsu-Tian

1999-03-01

In this paper, we propose a new nonlinear adaptive inverse control via a unified model neural network. In order to overcome nonsystematic design and long training time in nonlinear adaptive inverse control, we propose the approximate transformable technique to obtain a Chebyshev Polynomials Based Unified Model (CPBUM) neural network for the feedforward/recurrent neural networks. It turns out that the proposed method can use less training time to get an inverse model. Finally, we apply this proposed method to control magnetic bearing system. The experimental results show that the proposed nonlinear adaptive inverse control architecture provides a greater flexibility and better performance in controlling magnetic bearing systems.

Novel treatment concepts in Hodgkin lymphoma

NARCIS (Netherlands)

Glimelius, I.; Diepstra, A.

Treatment of classical Hodgkin's lymphoma (HL) has been a success story, with cure of localized disease with radiotherapy in the 1930s, cure of advanced stages with combination chemotherapy with/without radiotherapy in the mid-1960s and continuous improvements since then. Nonetheless, at present

Reduced-order modelling of parameter-dependent, linear and nonlinear dynamic partial differential equation models.

Science.gov (United States)

Shah, A A; Xing, W W; Triantafyllidis, V

2017-04-01

In this paper, we develop reduced-order models for dynamic, parameter-dependent, linear and nonlinear partial differential equations using proper orthogonal decomposition (POD). The main challenges are to accurately and efficiently approximate the POD bases for new parameter values and, in the case of nonlinear problems, to efficiently handle the nonlinear terms. We use a Bayesian nonlinear regression approach to learn the snapshots of the solutions and the nonlinearities for new parameter values. Computational efficiency is ensured by using manifold learning to perform the emulation in a low-dimensional space. The accuracy of the method is demonstrated on a linear and a nonlinear example, with comparisons with a global basis approach.

Nonlinear GARCH model and 1 / f noise

Science.gov (United States)

Kononovicius, A.; Ruseckas, J.

2015-06-01

Auto-regressive conditionally heteroskedastic (ARCH) family models are still used, by practitioners in business and economic policy making, as a conditional volatility forecasting models. Furthermore ARCH models still are attracting an interest of the researchers. In this contribution we consider the well known GARCH(1,1) process and its nonlinear modifications, reminiscent of NGARCH model. We investigate the possibility to reproduce power law statistics, probability density function and power spectral density, using ARCH family models. For this purpose we derive stochastic differential equations from the GARCH processes in consideration. We find the obtained equations to be similar to a general class of stochastic differential equations known to reproduce power law statistics. We show that linear GARCH(1,1) process has power law distribution, but its power spectral density is Brownian noise-like. However, the nonlinear modifications exhibit both power law distribution and power spectral density of the 1 /fβ form, including 1 / f noise.

Model reduction of nonlinear systems subject to input disturbances

KAUST Repository

Ndoye, Ibrahima; Laleg-Kirati, Taous-Meriem

2017-01-01

The method of convex optimization is used as a tool for model reduction of a class of nonlinear systems in the presence of disturbances. It is shown that under some conditions the nonlinear disturbed system can be approximated by a reduced order

Calibration of the nonlinear ring model at the Diamond Light Source

Directory of Open Access Journals (Sweden)

R. Bartolini

2011-05-01

Full Text Available Nonlinear beam dynamics plays a crucial role in defining the performance of a storage ring. The beam lifetime, the injection efficiency, and the dynamic and momentum apertures available to the beam are optimized during the design phase by a proper optimization of the linear lattice and of the distribution of sextupole families. The correct implementation of the design model, especially the nonlinear part, is a nontrivial accelerator physics task. Several parameters of the nonlinear dynamics can be used to compare the real machine with the model and eventually to correct the accelerator. Most of these parameters are extracted from the analysis of turn-by-turn data after the excitation of betatron oscillations of the particles in the ring. We present the experimental results of the campaign of measurements carried out at the Diamond storage ring to characterize the nonlinear beam dynamics. A combination of frequency map analysis with the detuning with momentum measurements has allowed for a precise calibration of the nonlinear model that can accurately reproduce the nonlinear beam dynamics in Diamond.

Modeling vector nonlinear time series using POLYMARS

NARCIS (Netherlands)

de Gooijer, J.G.; Ray, B.K.

2003-01-01

A modified multivariate adaptive regression splines method for modeling vector nonlinear time series is investigated. The method results in models that can capture certain types of vector self-exciting threshold autoregressive behavior, as well as provide good predictions for more general vector

Colored noise and memory effects on formal spiking neuron models

Science.gov (United States)

da Silva, L. A.; Vilela, R. D.

2015-06-01

Simplified neuronal models capture the essence of the electrical activity of a generic neuron, besides being more interesting from the computational point of view when compared to higher-dimensional models such as the Hodgkin-Huxley one. In this work, we propose a generalized resonate-and-fire model described by a generalized Langevin equation that takes into account memory effects and colored noise. We perform a comprehensive numerical analysis to study the dynamics and the point process statistics of the proposed model, highlighting interesting new features such as (i) nonmonotonic behavior (emergence of peak structures, enhanced by the choice of colored noise characteristic time scale) of the coefficient of variation (CV) as a function of memory characteristic time scale, (ii) colored noise-induced shift in the CV, and (iii) emergence and suppression of multimodality in the interspike interval (ISI) distribution due to memory-induced subthreshold oscillations. Moreover, in the noise-induced spike regime, we study how memory and colored noise affect the coherence resonance (CR) phenomenon. We found that for sufficiently long memory, not only is CR suppressed but also the minimum of the CV-versus-noise intensity curve that characterizes the presence of CR may be replaced by a maximum. The aforementioned features allow to interpret the interplay between memory and colored noise as an effective control mechanism to neuronal variability. Since both variability and nontrivial temporal patterns in the ISI distribution are ubiquitous in biological cells, we hope the present model can be useful in modeling real aspects of neurons.

Computerised tomography in the staging of Hodgkin's disease and non-Hodgkin's lymphoma

International Nuclear Information System (INIS)

Vinnicombe, Sarah J.; Reznek, Rodney H.

2003-01-01

The last 25 years have seen major changes in the imaging investigation and subsequent management of patients with Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL); accurate staging is vital for prognostication and treatment in both, and particularly in HD. The choice of imaging modality for staging depends on its accuracy, impact on clinical decision-making, and availability. Modern CT scanners fulfil most of the desired criteria. The advent of CT scanning, along with the development of ever more effective chemotherapeutic regimens, has resulted in the virtual demise of bipedal lymphangiography (LAG) as a staging tool in patients with lymphoma. It has rendered superfluous a battery of other tests that were in routine use. This contribution reviews the evidence for the use of CT in preference to LAG. CT accurately depicts nodal enlargement above and below the diaphragm, has variable sensitivity for intra-abdominal visceral involvement and is generally outstanding in depicting the extent of disease, especially extranodal extension. Despite the advances in CT technology, there are still areas where CT performs less well (e.g. disease in normal-sized lymph nodes, splenic and bone marrow infiltration). The influence of technical factors, such as the use of intravenous contrast medium, is discussed. In some instances, CT is not the imaging modality of choice and the place of newer techniques such as MRI and endoscopic ultrasound will be reviewed. (orig.)

Likelihood-Based Inference in Nonlinear Error-Correction Models

DEFF Research Database (Denmark)

Kristensen, Dennis; Rahbæk, Anders

We consider a class of vector nonlinear error correction models where the transfer function (or loadings) of the stationary relation- ships is nonlinear. This includes in particular the smooth transition models. A general representation theorem is given which establishes the dynamic properties...... and a linear trend in general. Gaussian likelihood-based estimators are considered for the long- run cointegration parameters, and the short-run parameters. Asymp- totic theory is provided for these and it is discussed to what extend asymptotic normality and mixed normaity can be found. A simulation study...

Nab-paclitaxel/Rituximab-coated Nanoparticle AR160 in Treating Patients With Relapsed or Refractory B-Cell Non-Hodgkin Lymphoma

Science.gov (United States)

2018-04-17

Aggressive Non-Hodgkin Lymphoma; CD20 Positive; Recurrent B-Cell Non-Hodgkin Lymphoma; Recurrent Small Lymphocytic Lymphoma; Refractory B-Cell Non-Hodgkin Lymphoma; Refractory Small Lymphocytic Lymphoma

Modeling of Macroeconomics by a Novel Discrete Nonlinear Fractional Dynamical System

Directory of Open Access Journals (Sweden)

Zhenhua Hu

2013-01-01

Full Text Available We propose a new nonlinear economic system with fractional derivative. According to the Jumarie’s definition of fractional derivative, we obtain a discrete fractional nonlinear economic system. Three variables, the gross domestic production, inflation, and unemployment rate, are considered by this nonlinear system. Based on the concrete macroeconomic data of USA, the coefficients of this nonlinear system are estimated by the method of least squares. The application of discrete fractional economic model with linear and nonlinear structure is shown to illustrate the efficiency of modeling the macroeconomic data with discrete fractional dynamical system. The empirical study suggests that the nonlinear discrete fractional dynamical system can describe the actual economic data accurately and predict the future behavior more reasonably than the linear dynamic system. The method proposed in this paper can be applied to investigate other macroeconomic variables of more states.

Application of homotopy-perturbation method to nonlinear population dynamics models

International Nuclear Information System (INIS)

Chowdhury, M.S.H.; Hashim, I.; Abdulaziz, O.

2007-01-01

In this Letter, the homotopy-perturbation method (HPM) is employed to derive approximate series solutions of nonlinear population dynamics models. The nonlinear models considered are the multispecies Lotka-Volterra equations. The accuracy of this method is examined by comparison with the available exact and the fourth-order Runge-Kutta method (RK4)

Bone marrow in pediatric patients with Hodgkin's disease.

Science.gov (United States)

Khan, Fauzia Shafi; Hasan, Rabiya Fayyaz

2012-01-01

Hodgkin's disease is a malignant process of lymphoreticular system that constitutes 6% of childhood cancers Accurate staging of lymphoma is the basis for rational therapeutic planning and assessment of the presence or absence of marrow involvement is a basic part of the staging evaluation. The objective of this study was to determine the incidence of marrow infiltration in paediatric patients with Hodgkin's disease and to ascertain its morphological spectrum in the marrow. The study included 85 paediatric patients with diagnosed Hodgkin's disease seen at The Children's Hospital/Institute of Child Health, Lahore, from January 2010 to December 2011, referred to haematology department for bone marrow biopsies. Ages ranged between two years to fourteen years with an average age of seven years, the male female ratio being 13:1. Mixed cellularity was the commonest histological type present in 66 (78%) cases. The presenting feature common in all cases was superficial lymphadenopathy followed by hepatomegaly in 17 (20%) cases and splenomegaly in 16 (19%). All the marrow aspirates were negative for infiltration. Trephine biopsies revealed marrow infiltration in 9 (10.5%). Five (56%) cases had bilateral while 4 (44%) had unilateral involvement. Pattern of infiltration was diffuse in 8 (89%) and focal in one (11%) trephines. Increased marrow fibrosis was present in eight (89%) cases. Diagnostic Reed Sternberg cells were identified in only one case and the mononuclear variants were present in six cases and atypical cells were present in two cases in these immunohistochemistry for CD15 and CD30 was performed which was positive. Granulomas in one and lymphoid aggregates were present in two trephine biopsies otherwise negative for Hodgkin's infiltration. Bone marrow infiltration was present in 10.5% cases, immunohistochemistry was used to confirm infiltration in two cases, the pattern of infiltration being diffuse in majority (89%).

Dynamics of the exponential integrate-and-fire model with slow currents and adaptation.

Science.gov (United States)

Barranca, Victor J; Johnson, Daniel C; Moyher, Jennifer L; Sauppe, Joshua P; Shkarayev, Maxim S; Kovačič, Gregor; Cai, David

2014-08-01

In order to properly capture spike-frequency adaptation with a simplified point-neuron model, we study approximations of Hodgkin-Huxley (HH) models including slow currents by exponential integrate-and-fire (EIF) models that incorporate the same types of currents. We optimize the parameters of the EIF models under the external drive consisting of AMPA-type conductance pulses using the current-voltage curves and the van Rossum metric to best capture the subthreshold membrane potential, firing rate, and jump size of the slow current at the neuron's spike times. Our numerical simulations demonstrate that, in addition to these quantities, the approximate EIF-type models faithfully reproduce bifurcation properties of the HH neurons with slow currents, which include spike-frequency adaptation, phase-response curves, critical exponents at the transition between a finite and infinite number of spikes with increasing constant external drive, and bifurcation diagrams of interspike intervals in time-periodically forced models. Dynamics of networks of HH neurons with slow currents can also be approximated by corresponding EIF-type networks, with the approximation being at least statistically accurate over a broad range of Poisson rates of the external drive. For the form of external drive resembling realistic, AMPA-like synaptic conductance response to incoming action potentials, the EIF model affords great savings of computation time as compared with the corresponding HH-type model. Our work shows that the EIF model with additional slow currents is well suited for use in large-scale, point-neuron models in which spike-frequency adaptation is important.

Second cancers following non-Hodgkin's lymphoma

International Nuclear Information System (INIS)

Travis, L.B.; Curtis, R.E.; Boice, J.D. Jr.; Hankey, B.F.; Fraumeni, J.F. Jr.

1991-01-01

The risk of second malignancies following non-Hodgkin's lymphoma (NHL) was estimated in 29,153 patients diagnosed with NHL between 1973 and 1987 in one of nine areas participating in the National Cancer Institute's Surveillance, Epidemiology, and End Results Program. Compared with the general population, NHL patients were at a significantly increased risk of developing second cancers (observed/expected [O/E] = 1.18; O = 1231). The O/E ratio increased significantly with time to reach 1.77 in 10-year survivors. Significant excesses were noted for acute nonlymphocytic leukemia (O/E = 2.88), cancers of the bladder (O/E = 1.30), kidney (O/E = 1.47), and lung (O/E = 1.57), malignant melanoma (O/E = 2.44), and Hodgkin's disease (O/E = 4.16). Chemotherapy appeared related to subsequent acute nonlymphocytic leukemia (ANLL) and bladder cancer. Radiation therapy was associated with ANLL and possibly cancers of the lung, bladder, and bone. Malignant melanoma was not clearly related to initial NHL treatment

Non-Coding RNAs in Hodgkin Lymphoma

Directory of Open Access Journals (Sweden)

Anna Cordeiro

2017-05-01

Full Text Available MicroRNAs (miRNAs, small non-coding RNAs that regulate gene expression by binding to the 3’-UTR of their target genes, can act as oncogenes or tumor suppressors. Recently, other types of non-coding RNAs—piwiRNAs and long non-coding RNAs—have also been identified. Hodgkin lymphoma (HL is a B cell origin disease characterized by the presence of only 1% of tumor cells, known as Hodgkin and Reed-Stenberg (HRS cells, which interact with the microenvironment to evade apoptosis. Several studies have reported specific miRNA signatures that can differentiate HL lymph nodes from reactive lymph nodes, identify histologic groups within classical HL, and distinguish HRS cells from germinal center B cells. Moreover, some signatures are associated with survival or response to chemotherapy. Most of the miRNAs in the signatures regulate genes related to apoptosis, cell cycle arrest, or signaling pathways. Here we review findings on miRNAs in HL, as well as on other non-coding RNAs.

Modelling and control of a nonlinear magnetostrictive actuator system

Science.gov (United States)

Ramli, M. H. M.; Majeed, A. P. P. Abdul; Anuar, M. A. M.; Mohamed, Z.

2018-04-01

This paper explores the implementation of a feedforward control method to a nonlinear control system, in particular, Magnetostrictive Actuators (MA) that has excellent properties of energy conversion between the mechanical and magnetic form through magnetostriction effects which could be used in actuating and sensing application. MA is known to exhibit hysteresis behaviour and it is rate dependent (the level of hysteresis depends closely on the rate of input excitation frequency). This is, nonetheless, an undesirable behaviour and has to be eliminated in realising high precision application. The MA is modelled by a phenomenological modelling approach via Prandtl-Ishlinskii (P-I) operator to characterise the hysteresis nonlinearities. A feedforward control strategy is designed and implemented to linearize and eliminate the hysteresis by model inversion. The results show that the P-I operator has the capability to model the hysteretic nonlinearity of MA with an acceptable accuracy. Furthermore, the proposed control scheme has demonstrated to be effective in providing superior trajectory tracking.

ALTERNATIVE EQUATIONS FOR DYNAMIC BEHAVIOR OF IONIC CHANNEL ACTIVATION AND INACTIVATION GATES

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Mahmut ÖZER

2003-03-01

Full Text Available In this paper, alternative equations for dynamics of ionic channel activation and inactivation gates are proposed based on the path probability method. Dynamic behavior of a voltage-gated ionic channel is modeled by the conventional Hodgkin-Huxley (H-H mathematical formalism. In that model, conductance of the channel is defined in terms of activation and inactivation gates. Dynamics of the activation and inactivation gates is modeled by first-order differential equations dependent on the gate variable and the membrane potential. In the new approach proposed in this study, dynamic behavior of activation and inactivation gates is modeled by a firstorder differential equation dependent on internal energy and membrane potential by using the path probability method which is widely used in statistical physics. The new model doesn't require the time constant and steadystate values which are used explicitly in the H-H model. The numerical results show validity of the proposed method.

A Challenging Case of Primary Breast Hodgkin's Lymphoma.

Science.gov (United States)

Zarnescu, Narcis Octavian; Iliesiu, Andreea; Procop, Alexandru; Tampa, Mircea; Matei, Clara; Sajin, Maria; Costache, Mariana; Dumitru, Adrian; Lazaroiu, Anca Mihaela

2015-03-01

Primary breast lymphoma (PBL) is a rare entity accounting for less than 1% of all breast malignancies. Diagnostic criteria for primary Hodgkin's lymphoma of the breast are: the presence of sufficient tissue for diagnosis, close interaction between mammary tissue and lymphomatous infiltrate and no evidence or prior diagnosis of widespread lymphoma. Our case illustrates an unusual presentation of Hodgkin's lymphoma of the breast: clinically as inflammatory breast cancer and core biopsy as granulomatous mastitis, the final diagnosis requiring surgical biopsy. Current information regarding this entity is scant, mainly build upon its rarity. In this paper we assess the clinical presentation, the step-by-step diagnosis, the treatment and the importance of immunohistochemistry in this uncommon condition.

Ionic currents and charge movements in organ-cultured rat skeletal muscle.

Science.gov (United States)

Hollingworth, S; Marshall, M W; Robson, E

1984-12-01

The middle of the fibre voltage-clamp technique was used to measure ionic currents and non-linear charge movements in intact, organ-cultured (in vitro denervated) mammalian fast-twitch (rat extensor digitorum longus) muscle fibres. Muscle fibres organ cultured for 4 days can be used as electrophysiological and morphological models for muscles in vivo denervated for the same length of time. Sodium currents in organ-cultured muscle fibres are similar to innervated fibres except that in the temperature range 0-20 degrees C (a) in the steady state, the voltage distribution of inactivation in cultured fibres is shifted negatively some 20 mV; (b) at the same temperature and membrane potential, the time constant of inactivation in cultured fibres is about twice that of innervated fibres. Potassium currents in innervated and cultured fibres at 15 degrees C can be fitted with the Hodgkin-Huxley n variable raised to the second power. Despite the large range we would estimate that the maximum value of the steady-state potassium conductance of cultured fibres is about one-half that of innervated fibres. The estimated maximum amount of charge moved in cultured fibre is about one-third that in innervated fibres. Compared to innervated fibres, culturing doubles the kinetics of the decay phase of charge movement. The possibility of a negative shift of the voltage distribution of charge movements in cultured fibres is discussed.

MiR-17/106b seed family regulates p21 in Hodgkin's lymphoma

NARCIS (Netherlands)

Gibcus, Johan H.; Kroesen, Bart-Jan; Koster, Roelof; Halsema, Nancy; de Jong, Debora; de Jong, Steven; Poppema, Sibrand; Kluiver, Joost; Diepstra, Arjan; van den Berg, Anke

2011-01-01

Hodgkin's lymphoma (HL) is a B cell-derived lymphoma characterized by a minority of malignant Hodgkin Reed-Sternberg (HRS) cells that have lost their normal B cell phenotype. Alterations in the cell cycle and apoptosis pathways might contribute to their resistance to apoptosis and sustained cell

Parametric model of servo-hydraulic actuator coupled with a nonlinear system: Experimental validation

Science.gov (United States)

Maghareh, Amin; Silva, Christian E.; Dyke, Shirley J.

2018-05-01

Hydraulic actuators play a key role in experimental structural dynamics. In a previous study, a physics-based model for a servo-hydraulic actuator coupled with a nonlinear physical system was developed. Later, this dynamical model was transformed into controllable canonical form for position tracking control purposes. For this study, a nonlinear device is designed and fabricated to exhibit various nonlinear force-displacement profiles depending on the initial condition and the type of materials used as replaceable coupons. Using this nonlinear system, the controllable canonical dynamical model is experimentally validated for a servo-hydraulic actuator coupled with a nonlinear physical system.

Practical Soil-Shallow Foundation Model for Nonlinear Structural Analysis

Directory of Open Access Journals (Sweden)

Moussa Leblouba

2016-01-01

Full Text Available Soil-shallow foundation interaction models that are incorporated into most structural analysis programs generally lack accuracy and efficiency or neglect some aspects of foundation behavior. For instance, soil-shallow foundation systems have been observed to show both small and large loops under increasing amplitude load reversals. This paper presents a practical macroelement model for soil-shallow foundation system and its stability under simultaneous horizontal and vertical loads. The model comprises three spring elements: nonlinear horizontal, nonlinear rotational, and linear vertical springs. The proposed macroelement model was verified using experimental test results from large-scale model foundations subjected to small and large cyclic loading cases.

Nonlinear modeling of a rotational MR damper via an enhanced Bouc–Wen model

International Nuclear Information System (INIS)

Miah, Mohammad S; Chatzi, Eleni N; Dertimanis, Vasilis K; Weber, Felix

2015-01-01

The coupling of magnetorheological (MR) dampers with semi-active control schemes has proven to be an effective and failsafe approach for vibration mitigation of low-damped structures. However, due to the nonlinearities inherently relating to such damping devices, the characterization of the associated nonlinear phenomena is still a challenging task. Herein, an enhanced phenomenological modeling approach is proposed for the description of a rotational-type MR damper, which comprises a modified Bouc–Wen model coupled with an appropriately selected sigmoid function. In a first step, parameter optimization is performed on the basis of individual models in an effort to approximate the experimentally observed response for varying current levels and actuator force characteristics. In a second step, based on the previously identified parameters, a generalized best-fit model is proposed by performing a regression analysis. Finally, model validation is carried out via implementation on different sets of experimental data. The proposed model indeed renders an improved representation of the actually observed nonlinear behavior of the tested rotational MR damper. (paper)

An analog model for quantum lightcone fluctuations in nonlinear optics

International Nuclear Information System (INIS)

Ford, L.H.; De Lorenci, V.A.; Menezes, G.; Svaiter, N.F.

2013-01-01

We propose an analog model for quantum gravity effects using nonlinear dielectrics. Fluctuations of the spacetime lightcone are expected in quantum gravity, leading to variations in the flight times of pulses. This effect can also arise in a nonlinear material. We propose a model in which fluctuations of a background electric field, such as that produced by a squeezed photon state, can cause fluctuations in the effective lightcone for probe pulses. This leads to a variation in flight times analogous to that in quantum gravity. We make some numerical estimates which suggest that the effect might be large enough to be observable. - Highlights: ► Lightcone fluctuations, quantum fluctuations of the effective speed of light, are a feature of quantum gravity. ► Nonlinear dielectrics have a variable speed of light, analogous to the effects of gravity. ► Fluctuating electric fields create the effect of lightcone fluctuations in a nonlinear material. ► We propose to use squeezed light in a nonlinear material as an analog model of lightcone fluctuations. ► Variation in the speed of propagation of pulses is the observational signature of lightcone fluctuations.

[No Hodgkin Linfoma diagnosis with intra-atrial infiltration].

Science.gov (United States)

Alcocer Gamba, Marco Antonio; León González, Salvador; Castro Montes, Eliodoro; Loarca Piña, Luis Martín; Lugo Gavidia, Leslie Marisol; García Hernández, Enrique; González Galindo, Ulises; Paredes Serrano, Miguel Isaías

2012-09-01

Cardiac tumors are rare entities in clinical practice, with an incidence of 0.05%. Approximately 75% are benign and 25% malignant. Among these, Lymphomas are uncommon, representing about 0.25%. The non-Hodgkin lymphomas can occur in extranodal tissues in 20% of the cases and 80% of these non-Hodgkin lymphomas are composed of diffuse B cells. The extranodal presentation is most frequent in young adults, with a high degree of malignancy and rapid growth. It can present with primary infiltration of various organs; cardiac involvement occurs in 20 to 28% of cases, usually located in the right chambers and with nonspecific symptoms, depending on the location and extent of the tumor. The diagnostic test in these cases is undoubtedly the biopsy of the lymph node or the affected tissue. We present the case of non-Hodgkin disease of diffuse large cells, with right intra-atrial involvement in a 23-year-old-female patient, who presented with progressive dyspnea. A transesophageal echocardiography was performed and an intra-atrial tumor mass was detected. A biopsy was performed, by femoral venous catheterization, allowing the establishment of the histopathological diagnosis and treatment. At a one year follow up, the patient shows complete remission.

Chronic Prurigo: An Unusual Presentation of Hodgkin Lymphoma

Directory of Open Access Journals (Sweden)

Shireen Dumont

2018-05-01

Full Text Available Background: Prurigo nodularis is a condition of unknown origin defined by papulonodular eruption and intense pruritus. Hodgkin lymphoma often presents nonspecific initial symptoms. An association between systemic malignancy and cutaneous manifestations has long been documented. We report a case of prurigo nodularis as a first presentation of Hodgkin lymphoma. Case: A 35-year-old woman presented with a 2-year history of pruritus. Previously diagnosed with bedbugs, the pruritus persisted even after insect eradication, with the appearance of papulonodular lesions consistent with chronic prurigo. The pruritus and the pain were refractory to all treatments. She had no past medical history or clinical, radiological, or laboratory findings. A lymphadenopathy was revealed 2 years after onset of the symptoms. Lymph node biopsy showed a nodular sclerosis Hodgkin lymphoma. The patient was initiated on chemotherapy and the skin lesions decreased. Conclusion: This case report of chronic prurigo as the first manifestation of a systemic malignancy reminds us of the importance of a systematic diagnostic approach to this kind of patients initially and throughout time, especially if the symptoms do not respond to treatment. Our case may question the role of imaging examinations in the management and follow-up of a persistent prurigo nodularis.

Special class of nonlinear damping models in flexible space structures

Science.gov (United States)

Hu, Anren; Singh, Ramendra P.; Taylor, Lawrence W.

1991-01-01

A special class of nonlinear damping models is investigated in which the damping force is proportional to the product of positive integer or the fractional power of the absolute values of displacement and velocity. For a one-degree-of-freedom system, the classical Krylov-Bogoliubov 'averaging' method is used, whereas for a distributed system, both an ad hoc perturbation technique and the finite difference method are employed to study the effects of nonlinear damping. The results are compared with linear viscous damping models. The amplitude decrement of free vibration for a single mode system with nonlinear models depends not only on the damping ratio but also on the initial amplitude, the time to measure the response, the frequency of the system, and the powers of displacement and velocity. For the distributed system, the action of nonlinear damping is found to reduce the energy of the system and to pass energy to lower modes.

Fertility preservation after chemotherapy for Hodgkin lymphoma

NARCIS (Netherlands)

van der Kaaij, Marleen A. E.; van Echten-Arends, Jannie; Simons, Arnold H. M.; Kluin-Nelemans, Hanneke C.

2010-01-01

Treatment for Hodgkin lymphoma can negatively affect fertility. This review summarizes data on fertility after chemotherapy in adult patients. Alkylating chemotherapy, especially if containing procarbazine and/or cyclophosphamide, is most harmful to gonadal functioning. Alkylating regimens cause

Hodgkin's disease in childhood

International Nuclear Information System (INIS)

Misol Perez, A.; Dabezies Antia, A.

1994-01-01

Actually, the majority of the children that suffer from Hodgkin illness can have long period of survive. The cures are related with the continuous achievements in biology molecular; techniques of different state, radiotherapy, chemotherapy, imagenology, proceedings and to the multidisciplinary handling. This article summarizes those aspects related with the illness and its treatment, taking in count the biggest impact of the secondary effects on children and adolescents that are in growth and active development. (Au) [es

A Non-linear Stochastic Model for an Office Building with Air Infiltration

DEFF Research Database (Denmark)

Thavlov, Anders; Madsen, Henrik

2015-01-01

This paper presents a non-linear heat dynamic model for a multi-room office building with air infiltration. Several linear and non-linear models, with and without air infiltration, are investigated and compared. The models are formulated using stochastic differential equations and the model...

Nonlinear modeling and identification of a DC motor for bidirectional operation with real time experiments

International Nuclear Information System (INIS)

Kara, Tolgay; Eker, Ilyas

2004-01-01

Modeling and identification of mechanical systems constitute an essential stage in practical control design and applications. Controllers commanding systems that operate at varying conditions or require high precision operation raise the need for a nonlinear approach in modeling and identification. Most mechanical systems used in industry are composed of masses moving under the action of position and velocity dependent forces. These forces exhibit nonlinear behavior in certain regions of operation. For a multi-mass rotational system, the nonlinearities, like Coulomb friction and dead zone, significantly influence the system operation when the rotation changes direction. The paper presents nonlinear modeling and identification of a DC motor rotating in two directions together with real time experiments. Linear and nonlinear models for the system are obtained for identification purposes, and the major nonlinearities in the system, such as Coulomb friction and dead zone, are investigated and integrated in the nonlinear model. The Hammerstein nonlinear system approach is used for identification of the nonlinear system model. Online identification of the linear and nonlinear system models is performed using the recursive least squares method. Results of the real time experiments are graphically and numerically presented, and the advantages of the nonlinear identification approach are revealed

On the nonlinear modeling of ring oscillators

KAUST Repository

Elwakil, Ahmed S.

2009-06-01

We develop higher-order nonlinear models of three-stage and five-stage ring oscillators based on a novel inverter model. The oscillation condition and oscillation frequency are derived and compared to classical linear model analysis. Two important special cases for five-stage ring oscillators are also studied. Numerical simulations are shown. © 2009 World Scientific Publishing Company.

On the nonlinear modeling of ring oscillators

KAUST Repository

Elwakil, Ahmed S.; Salama, Khaled N.

2009-01-01

We develop higher-order nonlinear models of three-stage and five-stage ring oscillators based on a novel inverter model. The oscillation condition and oscillation frequency are derived and compared to classical linear model analysis. Two important special cases for five-stage ring oscillators are also studied. Numerical simulations are shown. © 2009 World Scientific Publishing Company.

Nonlinear signal processing using neural networks: Prediction and system modelling

Energy Technology Data Exchange (ETDEWEB)

Lapedes, A.; Farber, R.

1987-06-01

The backpropagation learning algorithm for neural networks is developed into a formalism for nonlinear signal processing. We illustrate the method by selecting two common topics in signal processing, prediction and system modelling, and show that nonlinear applications can be handled extremely well by using neural networks. The formalism is a natural, nonlinear extension of the linear Least Mean Squares algorithm commonly used in adaptive signal processing. Simulations are presented that document the additional performance achieved by using nonlinear neural networks. First, we demonstrate that the formalism may be used to predict points in a highly chaotic time series with orders of magnitude increase in accuracy over conventional methods including the Linear Predictive Method and the Gabor-Volterra-Weiner Polynomial Method. Deterministic chaos is thought to be involved in many physical situations including the onset of turbulence in fluids, chemical reactions and plasma physics. Secondly, we demonstrate the use of the formalism in nonlinear system modelling by providing a graphic example in which it is clear that the neural network has accurately modelled the nonlinear transfer function. It is interesting to note that the formalism provides explicit, analytic, global, approximations to the nonlinear maps underlying the various time series. Furthermore, the neural net seems to be extremely parsimonious in its requirements for data points from the time series. We show that the neural net is able to perform well because it globally approximates the relevant maps by performing a kind of generalized mode decomposition of the maps. 24 refs., 13 figs.

Las matemáticas en la transmisión del impulso nervioso

OpenAIRE

García García, Lara

2016-01-01

En este trabajo se analizan algunos de los modelos que describen la transmisión del impulso nervioso o sinapsis neuronal. Más concretamente, el modelo de Hodgkin y Huxley (por el que ganaron el premio Nobel de Fisiología en 1963) y otros modelos simplificados de FitzHugh y Nagumo y McKean. Se determinan condiciones sobre los parámetros que aparecen en los modelos para que existan soluciones del tipo observado en los experimentos originales de los fisiólogos. Grado en Matemáticas

Neuroelectronics and modeling of electrical signals for monitoring and control of Parkinson's disease

Science.gov (United States)

Chintakuntla, Ritesh R.; Abraham, Jose K.; Varadan, Vijay K.

2009-03-01

The brain and the human nervous system are perhaps the most researched but least understood components of the human body. This is so because of the complex nature of its working and the high density of functions. The monitoring of neural signals could help one better understand the working of the brain and newer recording and monitoring methods have been developed ever since it was discovered that the brain communicates internally by means of electrical pulses. Neuroelectronics is the field which deals with the interface between electronics or semiconductors to living neurons. This includes monitoring of electrical activity from the brain as well as the development of feedback devices for stimulation of parts of the brain for treatment of disorders. In this paper these electrical signals are modeled through a nano/microelectrode arrays based on the electronic equivalent model using Cadence PSD 15.0. The results were compared with those previously published models such as Kupfmuller and Jenik's model, McGrogan's Neuron Model which are based on the Hodgkin and Huxley model. We have developed and equivalent circuit model using discrete passive components to simulate the electrical activity of the neurons. The simulated circuit can be easily be modified by adding some more ionic channels and the results can be used to predict necessary external stimulus needed for stimulation of neurons affected by the Parkinson's disease (PD). Implementing such a model in PD patients could predict the necessary voltages required for the electrical stimulation of the sub-thalamus region for the control tremor motion.

A model of nonlinear strain and damage accumulation in polymer composites

Directory of Open Access Journals (Sweden)

A. N. Ruslantsev

2014-01-01

Full Text Available This paper presents a model to predict a nonlinear strain of the carbon laminate; the model is based on the relations between the theory of laminated plates and the non-linear approximation of deformation curve of unidirectional layer at the shear in the layer plane. The explicit expressions of stiffness and compliance matrices were obtained via multiplying the matrices that correspond to the elastic characteristics by the matrices, considering the non-linear properties of the laminate. The paper suggests an approximation option for the non-linear properties of the layer at the shear using an exponential function. Some considerations on damage accumulation in carbon laminates were made.

A REMARK ON FORMAL MODELS FOR NONLINEARLY ELASTIC MEMBRANE SHELLS

Institute of Scientific and Technical Information of China (English)

无

2001-01-01

This paper gives all the two-dimensional membrane models obtained from formal asymptotic analysis of the three-dimensional geometrically exact nonlinear model of a thin elastic shell made with a Saint Venant-Kirchhoff material. Therefore, the other models can be quoted as flexural nonlinear ones. The author also gives the formal equations solved by the associated stress tensor and points out that only one of those models leads, by linearization, to the “classical” linear limiting membrane model, whose juetification has already been established by a convergence theorem.

SEPTIN2 and STATHMIN Regulate CD99-Mediated Cellular Differentiation in Hodgkin's Lymphoma.

Directory of Open Access Journals (Sweden)

Wenjing Jian

Full Text Available Hodgkin's lymphoma (HL is a lymphoid neoplasm characterized by Hodgkin's and Reed-Sternberg (H/RS cells, which is regulated by CD99. We previously reported that CD99 downregulation led to the transformation of murine B lymphoma cells (A20 into cells with an H/RS phenotype, while CD99 upregulation induced differentiation of classical Hodgkin's lymphoma (cHL cells (L428 into terminal B-cells. However, the molecular mechanism remains unclear. In this study, using fluorescence two-dimensional differential in-gel electrophoresis and matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS, we have analyzed the alteration of protein expression following CD99 upregulation in L428 cells as well as downregulation of mouse CD99 antigen-like 2 (mCD99L2 in A20 cells. Bioinformatics analysis showed that SEPTIN2 and STATHMIN, which are cytoskeleton proteins, were significantly differentially expressed, and chosen for further validation and functional analysis. Differential expression of SEPTIN2 was found in both models and was inversely correlated with CD99 expression. STATHMIN was identified in the A20 cell line model and its expression was positively correlated with that of CD99. Importantly, silencing of SEPTIN2 with siRNA substantially altered the cellular cytoskeleton in L428 cells. The downregulation of STATHMIN by siRNA promoted the differentiation of H/RS cells toward terminal B-cells. These results suggest that SEPTIN2-mediated cytoskeletal rearrangement and STATHMIN-mediated differentiation may contribute to changes in cell morphology and differentiation of H/RS cells with CD99 upregulation in HL.

A new nonlinear turbulence model based on Partially-Averaged Navier-Stokes Equations

International Nuclear Information System (INIS)

Liu, J T; Wu, Y L; Cai, C; Liu, S H; Wang, L Q

2013-01-01

Partially-averaged Navier-Stokes (PANS) Model was recognized as a Reynolds-averaged Navier-Stokes (RANS) to direct numerical simulation (DNS) bridging method. PANS model was purported for any filter width-from RANS to DNS. PANS method also shared some similarities with the currently popular URANS (unsteady RANS) method. In this paper, a new PANS model was proposed, which was based on RNG k-ε turbulence model. The Standard and RNG k-ε turbulence model were both isotropic models, as well as PANS models. The sheer stress in those PANS models was solved by linear equation. The linear hypothesis was not accurate in the simulation of complex flow, such as stall phenomenon. The sheer stress here was solved by nonlinear method proposed by Ehrhard. Then, the nonlinear PANS model was set up. The pressure coefficient of the suction side of the NACA0015 hydrofoil was predicted. The result of pressure coefficient agrees well with experimental result, which proves that the nonlinear PANS model can capture the high pressure gradient flow. A low specific centrifugal pump was used to verify the capacity of the nonlinear PANS model. The comparison between the simulation results of the centrifugal pump and Particle Image Velocimetry (PIV) results proves that the nonlinear PANS model can be used in the prediction of complex flow field

Linfoma não-Hodgkin apresentando-se como massa hepática única Non-Hodgkin's lymphoma presenting as a single liver mass

Directory of Open Access Journals (Sweden)

Mila Correia Góis Peixoto

2009-02-01

Full Text Available OBJETIVO: Descrever as principais características de imagem do linfoma não-Hodgkin apresentando-se como massa hepática única. MATERIAIS E MÉTODOS: Realizamos estudo retrospectivo mediante análise de casos de pacientes com massa hepática única aos exames de ultrassonografia, tomografia computadorizada e ressonância magnética, com diagnóstico histológico de linfoma não-Hodgkin. Esses exames foram analisados por dois examinadores em consenso. RESULTADOS: Identificamos três pacientes, todos do sexo masculino, na quinta década de vida, com quadro clínico inespecífico e que apresentavam massa hepática única e com diagnóstico de linfoma não-Hodgkin. Na ultrassonografia a lesão hepática apresentava-se como massa com aspecto "em alvo" nos três casos estudados. Na tomografia computadorizada observou-se massa hipodensa e heterogênea, com realce anelar em todos os casos. Na ressonância magnética as lesões apresentavam-se heterogêneas, hipointensas em T1 e hiperintensas em T2, e também com realce anelar após a injeção do contraste. Nenhum paciente apresentava linfonodomegalia ou comprometimento de outras vísceras sólidas no momento do diagnóstico. CONCLUSÃO: Na presença de massa hepática solitária e com aspecto "em alvo" deve-se considerar, entre as hipóteses, o diagnóstico de linfoma.OBJECTIVE: To describe the main imaging findings of non-Hodgkin's lymphoma presenting as a single liver mass. MATERIALS AND METHODS: A retrospective study was developed with analysis of cases where a single liver mass was observed at ultrasonography, computed tomography and magnetic resonance imaging, and histologically diagnosed as non-Hodgkin's lymphoma. The studies were reviewed by two observers in consensus. RESULTS: Three male patients in the fifth decade of life, with non-specific clinical manifestations and single liver mass diagnosed as non-Hodgkin's lymphoma were identified. A hepatic lesion with target sign was observed at

A Nonlinear Dynamic Model and Free Vibration Analysis of Deployable Mesh Reflectors

Science.gov (United States)

Shi, H.; Yang, B.; Thomson, M.; Fang, H.

2011-01-01

This paper presents a dynamic model of deployable mesh reflectors, in which geometric and material nonlinearities of such a space structure are fully described. Then, by linearization around an equilibrium configuration of the reflector structure, a linearized model is obtained. With this linearized model, the natural frequencies and mode shapes of a reflector can be computed. The nonlinear dynamic model of deployable mesh reflectors is verified by using commercial finite element software in numerical simulation. As shall be seen, the proposed nonlinear model is useful for shape (surface) control of deployable mesh reflectors under thermal loads.

Nonlinear unitary quantum collapse model with self-generated noise

Science.gov (United States)

Geszti, Tamás

2018-04-01

Collapse models including some external noise of unknown origin are routinely used to describe phenomena on the quantum-classical border; in particular, quantum measurement. Although containing nonlinear dynamics and thereby exposed to the possibility of superluminal signaling in individual events, such models are widely accepted on the basis of fully reproducing the non-signaling statistical predictions of quantum mechanics. Here we present a deterministic nonlinear model without any external noise, in which randomness—instead of being universally present—emerges in the measurement process, from deterministic irregular dynamics of the detectors. The treatment is based on a minimally nonlinear von Neumann equation for a Stern–Gerlach or Bell-type measuring setup, containing coordinate and momentum operators in a self-adjoint skew-symmetric, split scalar product structure over the configuration space. The microscopic states of the detectors act as a nonlocal set of hidden parameters, controlling individual outcomes. The model is shown to display pumping of weights between setup-defined basis states, with a single winner randomly selected and the rest collapsing to zero. Environmental decoherence has no role in the scenario. Through stochastic modelling, based on Pearle’s ‘gambler’s ruin’ scheme, outcome probabilities are shown to obey Born’s rule under a no-drift or ‘fair-game’ condition. This fully reproduces quantum statistical predictions, implying that the proposed non-linear deterministic model satisfies the non-signaling requirement. Our treatment is still vulnerable to hidden signaling in individual events, which remains to be handled by future research.

Radiotherapy in non-Hodgkin lymphomas

International Nuclear Information System (INIS)

Faria, S.L.

1992-01-01

The treatment of non-Hodgkin lymphomas (NHL) is discussed. The use of radiotherapy, chemotherapy or both in a combined therapy is studied considering several aspects as age of the patients (adults vs children), size and extension of the lymphoma, stage of the disease. It is mentioned that more advanced cases and those with more aggressive histology need combined modality treatments or even just chemotherapy. (M.A.C.)

Symmetries and discretizations of the O(3) nonlinear sigma model

Energy Technology Data Exchange (ETDEWEB)

Flore, Raphael [TPI, Universitaet Jena (Germany)

2011-07-01

Nonlinear sigma models possess many interesting properties like asymptotic freedom, confinement or dynamical mass generation, and hence serve as toy models for QCD and other theories. We derive a formulation of the N=2 supersymmetric extension of the O(3) nonlinear sigma model in terms of constrained field variables. Starting from this formulation, it is discussed how the model can be discretized in a way that maintains as many symmetries of the theory as possible. Finally, recent numerical results related to these discretizations are presented.

PRESS-based EFOR algorithm for the dynamic parametrical modeling of nonlinear MDOF systems

Science.gov (United States)

Liu, Haopeng; Zhu, Yunpeng; Luo, Zhong; Han, Qingkai

2017-09-01

In response to the identification problem concerning multi-degree of freedom (MDOF) nonlinear systems, this study presents the extended forward orthogonal regression (EFOR) based on predicted residual sums of squares (PRESS) to construct a nonlinear dynamic parametrical model. The proposed parametrical model is based on the non-linear autoregressive with exogenous inputs (NARX) model and aims to explicitly reveal the physical design parameters of the system. The PRESS-based EFOR algorithm is proposed to identify such a model for MDOF systems. By using the algorithm, we built a common-structured model based on the fundamental concept of evaluating its generalization capability through cross-validation. The resulting model aims to prevent over-fitting with poor generalization performance caused by the average error reduction ratio (AERR)-based EFOR algorithm. Then, a functional relationship is established between the coefficients of the terms and the design parameters of the unified model. Moreover, a 5-DOF nonlinear system is taken as a case to illustrate the modeling of the proposed algorithm. Finally, a dynamic parametrical model of a cantilever beam is constructed from experimental data. Results indicate that the dynamic parametrical model of nonlinear systems, which depends on the PRESS-based EFOR, can accurately predict the output response, thus providing a theoretical basis for the optimal design of modeling methods for MDOF nonlinear systems.

Model-based nonlinear control of hydraulic servo systems: Challenges, developments and perspectives

Science.gov (United States)

Yao, Jianyong

2018-06-01

Hydraulic servo system plays a significant role in industries, and usually acts as a core point in control and power transmission. Although linear theory-based control methods have been well established, advanced controller design methods for hydraulic servo system to achieve high performance is still an unending pursuit along with the development of modern industry. Essential nonlinearity is a unique feature and makes model-based nonlinear control more attractive, due to benefit from prior knowledge of the servo valve controlled hydraulic system. In this paper, a discussion for challenges in model-based nonlinear control, latest developments and brief perspectives of hydraulic servo systems are presented: Modelling uncertainty in hydraulic system is a major challenge, which includes parametric uncertainty and time-varying disturbance; some specific requirements also arise ad hoc difficulties such as nonlinear friction during low velocity tracking, severe disturbance, periodic disturbance, etc.; to handle various challenges, nonlinear solutions including parameter adaptation, nonlinear robust control, state and disturbance observation, backstepping design and so on, are proposed and integrated, theoretical analysis and lots of applications reveal their powerful capability to solve pertinent problems; and at the end, some perspectives and associated research topics (measurement noise, constraints, inner valve dynamics, input nonlinearity, etc.) in nonlinear hydraulic servo control are briefly explored and discussed.

Nonlinear finite element modeling of corrugated board

Science.gov (United States)

A. C. Gilchrist; J. C. Suhling; T. J. Urbanik

1999-01-01

In this research, an investigation on the mechanical behavior of corrugated board has been performed using finite element analysis. Numerical finite element models for corrugated board geometries have been created and executed. Both geometric (large deformation) and material nonlinearities were included in the models. The analyses were performed using the commercial...

Applications of Nonlinear Dynamics Model and Design of Complex Systems

CERN Document Server

In, Visarath; Palacios, Antonio

2009-01-01

This edited book is aimed at interdisciplinary, device-oriented, applications of nonlinear science theory and methods in complex systems. In particular, applications directed to nonlinear phenomena with space and time characteristics. Examples include: complex networks of magnetic sensor systems, coupled nano-mechanical oscillators, nano-detectors, microscale devices, stochastic resonance in multi-dimensional chaotic systems, biosensors, and stochastic signal quantization. "applications of nonlinear dynamics: model and design of complex systems" brings together the work of scientists and engineers that are applying ideas and methods from nonlinear dynamics to design and fabricate complex systems.

Finiteness of Ricci flat supersymmetric non-linear sigma-models

International Nuclear Information System (INIS)

Alvarez-Gaume, L.; Ginsparg, P.

1985-01-01

Combining the constraints of Kaehler differential geometry with the universality of the normal coordinate expansion in the background field method, we study the ultraviolet behavior of 2-dimensional supersymmetric non-linear sigma-models with target space an arbitrary riemannian manifold M. We show that the constraint of N=2 supersymmetry requires that all counterterms to the metric beyond one-loop order are cohomologically trivial. It follows that such supersymmetric non-linear sigma-models defined on locally symmetric spaces are super-renormalizable and that N=4 models are on-shell ultraviolet finite to all orders of perturbation theory. (orig.)

Orbital involvement by non-Hodgkin lymphoma NK T cells.

Science.gov (United States)

Hervás-Ontiveros, A; España-Gregori, E; Hernández-Martínez, P; Vera-Sempere, F J; Díaz-Llopis, M

2014-11-01

The case is presented of 37 year-old male with a history of nasal obstruction with right rhinorrhea, headache, hearing loss and right exophthalmos of 4 months progression. The MRI revealed that the ethmoidal and maxillary sinuses contained inflammatory tissue extending into the orbital region. The biopsy confirmed a non-Hodgkin lymphoma of natural killer (NK) T cells. Non-Hodgkin's T NK lymphoma is a rare tumor in the orbital area that requires an early detection and multi-disciplinary care to ensure appropriate monitoring and treatment. Copyright © 2012 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

SpikingLab: modelling agents controlled by Spiking Neural Networks in Netlogo.

Science.gov (United States)

Jimenez-Romero, Cristian; Johnson, Jeffrey

2017-01-01

The scientific interest attracted by Spiking Neural Networks (SNN) has lead to the development of tools for the simulation and study of neuronal dynamics ranging from phenomenological models to the more sophisticated and biologically accurate Hodgkin-and-Huxley-based and multi-compartmental models. However, despite the multiple features offered by neural modelling tools, their integration with environments for the simulation of robots and agents can be challenging and time consuming. The implementation of artificial neural circuits to control robots generally involves the following tasks: (1) understanding the simulation tools, (2) creating the neural circuit in the neural simulator, (3) linking the simulated neural circuit with the environment of the agent and (4) programming the appropriate interface in the robot or agent to use the neural controller. The accomplishment of the above-mentioned tasks can be challenging, especially for undergraduate students or novice researchers. This paper presents an alternative tool which facilitates the simulation of simple SNN circuits using the multi-agent simulation and the programming environment Netlogo (educational software that simplifies the study and experimentation of complex systems). The engine proposed and implemented in Netlogo for the simulation of a functional model of SNN is a simplification of integrate and fire (I&F) models. The characteristics of the engine (including neuronal dynamics, STDP learning and synaptic delay) are demonstrated through the implementation of an agent representing an artificial insect controlled by a simple neural circuit. The setup of the experiment and its outcomes are described in this work.

Non-linear mixed-effects pharmacokinetic/pharmacodynamic modelling in NLME using differential equations

DEFF Research Database (Denmark)

Tornøe, Christoffer Wenzel; Agersø, Henrik; Madsen, Henrik

2004-01-01

The standard software for non-linear mixed-effect analysis of pharmacokinetic/phar-macodynamic (PK/PD) data is NONMEM while the non-linear mixed-effects package NLME is an alternative as tong as the models are fairly simple. We present the nlmeODE package which combines the ordinary differential...... equation (ODE) solver package odesolve and the non-Linear mixed effects package NLME thereby enabling the analysis of complicated systems of ODEs by non-linear mixed-effects modelling. The pharmacokinetics of the anti-asthmatic drug theophylline is used to illustrate the applicability of the nlme...

Long-term pruritus as the initial and sole clinical manifestation of occult Hodgkin's disease.

Science.gov (United States)

Omidvari, Shapour H; Khojasteh, Habib Noorani; Mohammadianpanah, Mohammad; Monabati, Ahmad; Mosalaei, Ahmad; Ahmadloo, Niloofar

2004-06-01

Pruritus or itch is a frequent symptom of patients with Hodgkin's disease. It often occurs during the clinical course of the disease and rarely may precede the diagnosis of underlying disease. In this report, we present a 16-year-old patient who had history of generalized pruritus without any skin rash for 4 years before the diagnosis of Hodgkin's disease. Within that period, she had received symptom-oriented medications, with no significant effect. After the first cycle of chemotherapy, her pruritus resolved completely. This case suggests that long-term generalized pruritus may be indicative of a significant underlying problem like Hodgkin's disease.

Frequency Response of Synthetic Vocal Fold Models with Linear and Nonlinear Material Properties

Science.gov (United States)

Shaw, Stephanie M.; Thomson, Scott L.; Dromey, Christopher; Smith, Simeon

2012-01-01

Purpose: The purpose of this study was to create synthetic vocal fold models with nonlinear stress-strain properties and to investigate the effect of linear versus nonlinear material properties on fundamental frequency (F[subscript 0]) during anterior-posterior stretching. Method: Three materially linear and 3 materially nonlinear models were…

Coupled Particle Transport and Pattern Formation in a Nonlinear Leaky-Box Model

Science.gov (United States)

Barghouty, A. F.; El-Nemr, K. W.; Baird, J. K.

2009-01-01

Effects of particle-particle coupling on particle characteristics in nonlinear leaky-box type descriptions of the acceleration and transport of energetic particles in space plasmas are examined in the framework of a simple two-particle model based on the Fokker-Planck equation in momentum space. In this model, the two particles are assumed coupled via a common nonlinear source term. In analogy with a prototypical mathematical system of diffusion-driven instability, this work demonstrates that steady-state patterns with strong dependence on the magnetic turbulence but a rather weak one on the coupled particles attributes can emerge in solutions of a nonlinearly coupled leaky-box model. The insight gained from this simple model may be of wider use and significance to nonlinearly coupled leaky-box type descriptions in general.

Modal model for the nonlinear multimode Rayleigh endash Taylor instability

International Nuclear Information System (INIS)

Ofer, D.; Alon, U.; Shvarts, D.; McCrory, R.L.; Verdon, C.P.

1996-01-01

A modal model for the Rayleigh endash Taylor (RT) instability, applicable at all stages of the flow, is introduced. The model includes a description of nonlinear low-order mode coupling, mode growth saturation, and post-saturation mode coupling. It is shown to significantly extend the range of applicability of a previous model proposed by Haan, to cases where nonlinear mode generation is important. Using the new modal model, we study the relative importance of mode coupling at late nonlinear stages and resolve the difference between cases in which mode generation assumes a dominant role, leading to the late time inverse cascade of modes and loss of memory of initial conditions, and cases where mode generation is not important and memory of initial conditions is retained. Effects of finite density ratios (Atwood number A<1) are also included in the model and the difference between various measures of the mixing zone penetration depth for A<1 is discussed. copyright 1996 American Institute of Physics

Convex models and probabilistic approach of nonlinear fatigue failure

International Nuclear Information System (INIS)

Qiu Zhiping; Lin Qiang; Wang Xiaojun

2008-01-01

This paper is concerned with the nonlinear fatigue failure problem with uncertainties in the structural systems. In the present study, in order to solve the nonlinear problem by convex models, the theory of ellipsoidal algebra with the help of the thought of interval analysis is applied. In terms of the inclusion monotonic property of ellipsoidal functions, the nonlinear fatigue failure problem with uncertainties can be solved. A numerical example of 25-bar truss structures is given to illustrate the efficiency of the presented method in comparison with the probabilistic approach

Calibration of the Nonlinear Accelerator Model at the Diamond Storage Ring

CERN Document Server

Bartolini, Riccardo; Rowland, James; Martin, Ian; Schmidt, Frank

2010-01-01

The correct implementation of the nonlinear ring model is crucial to achieve the top performance of a synchrotron light source. Several dynamics quantities can be used to compare the real machine with the model and eventually to correct the accelerator. Most of these methods are based on the analysis of turn-by-turn data of excited betatron oscillations. We present the experimental results of the campaign of measurements carried out at the Diamond. A combination of Frequency Map Analysis (FMA) and detuning with momentum measurements has allowed a precise calibration of the nonlinear model capable of reproducing the nonlinear beam dynamics in the storage ring

Modeling of nonlinear responses for reciprocal transducers involving polarization switching

DEFF Research Database (Denmark)

Willatzen, Morten; Wang, Linxiang

2007-01-01

Nonlinearities and hysteresis effects in a reciprocal PZT transducer are examined by use of a dynamical mathematical model on the basis of phase-transition theory. In particular, we consider the perovskite piezoelectric ceramic in which the polarization process in the material can be modeled...... by Landau theory for the first-order phase transformation, in which each polarization state is associated with a minimum of the Landau free-energy function. Nonlinear constitutive laws are obtained by using thermodynamical equilibrium conditions, and hysteretic behavior of the material can be modeled...... intrinsically. The time-dependent Ginzburg-Landau theory is used in the parameter identification involving hysteresis effects. We use the Chebyshev collocation method in the numerical simulations. The elastic field is assumed to be coupled linearly with other fields, and the nonlinearity is in the E-D coupling...

Nonlinear Jaynes–Cummings model for two interacting two-level atoms

International Nuclear Information System (INIS)

Santos-Sánchez, O de los; González-Gutiérrez, C; Récamier, J

2016-01-01

In this work we examine a nonlinear version of the Jaynes–Cummings model for two identical two-level atoms allowing for Ising-like and dipole–dipole interplays between them. The model is said to be nonlinear in the sense that it can incorporate both a general intensity-dependent interaction between the atomic system and the cavity field and/or the presence of a nonlinear medium inside the cavity. As an example, we consider a particular type of atom-field coupling based upon the so-called Buck–Sukumar model and a lossless Kerr-like cavity. We describe the possible effects of such features on the evolution of some quantities of current interest, such as atomic excitation, purity, concurrence, the entropy of the field and the evolution of the latter in phase space. (paper)

System Identification for Nonlinear FOPDT Model with Input-Dependent Dead-Time

DEFF Research Database (Denmark)

Sun, Zhen; Yang, Zhenyu

2011-01-01

An on-line iterative method of system identification for a kind of nonlinear FOPDT system is proposed in the paper. The considered nonlinear FOPDT model is an extension of the standard FOPDT model by means that its dead time depends on the input signal and the other parameters are time dependent....

Utility of LRF/Pokemon and NOTCH1 protein expression in the distinction between nodular lymphocyte-predominant Hodgkin lymphoma and classical Hodgkin lymphoma.

Science.gov (United States)

Bohn, Olga; Maeda, Takahiro; Filatov, Alexander; Lunardi, Andrea; Pandolfi, Pier Paolo; Teruya-Feldstein, Julie

2014-02-01

Classical Hodgkin lymphoma (CHL) and nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) are considered separate entities with different prognosis and treatment. However, morphologic features can be similar and immunohistochemical studies are essential in the distinction; thus, determination of additional biomarkers is of utmost importance. LRF/Pokemon is a proto-oncogene, an interacting partner co-expressed with BCL6 in germinal centers and highly expressed in diffuse large B-cell lymphoma and follicular lymphoma. Conversely, loss of the LRF gene in mouse hematopoietic stem cells results in complete block of early B cell development with concomitant Notch de-repression, indicating its critical role in B versus T cell fate decision at the hematopoietic stem cell stage. For the first time, we show that LRF/Pokemon is predominantly expressed in NLPHL cases as is BCL6 with low to absent NOTCH1 protein expression; while Hodgkin Reed-Sternberg (HRS) cells in CHL show low to absent BCL6 and LRF/Pokemon expression with higher NOTCH1 expression. We illustrate a potential functional interaction between LRF and BCL6 in NLPHL pathogenesis, and differential expression of LRF/Pokemon and NOTCH1 proteins in CHL thus showing differential expression, making for an additional diagnostic marker and therapeutic target.

Utility of LRF/Pokemon and NOTCH1 Protein Expression in the Distinction of Nodular Lymphocyte-Predominant Hodgkin Lymphoma and Classical Hodgkin Lymphoma

Science.gov (United States)

Bohn, Olga; Maeda, Takahiro; Filatov, Alexander; Lunardi, Andrea; Pandolfi, Pier Paolo; Teruya-Feldstein, Julie

2014-01-01

Classical Hodgkin lymphoma (CHL) and nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) are considered separate entities with different prognosis and treatment. However, morphologic features can be similar and immunohistochemical studies are essential in the distinction; thus, determination of additional biomarkers is of utmost importance. LRF/Pokemon is a protooncogene, an interacting partner co-expressed with BCL6 in germinal centers and highly expressed in diffuse large B-cell lymphoma and follicular lymphoma. Conversely, loss of the LRF gene in mouse hematopoietic stem cells results in complete block of early B cell development with concomitant Notch derepression, indicating its critical role in B versus T cell fate decision at the hematopoietic stem cell stage. For the first time, we show that LRF/Pokemon is predominantly expressed in NLPHL cases as is BCL6 with low to absent NOTCH1 protein expression; while Hodgkin Reed-Sternberg (HRS) cells in CHL show low to absent BCL6 and LRF/Pokemon expression with higher NOTCH1 expression. We illustrate a potential functional interaction between LRF and BCL6 in NLPHL pathogenesis, and differential expression of LRF/Pokemon and NOTCH1 proteins in CHL thus showing differential expression, making for an additional diagnostic marker and therapeutic target. PMID:24326827

A phase II study of the oral JAK1/JAK2 inhibitor ruxolitinib in advanced relapsed/refractory Hodgkin lymphoma

NARCIS (Netherlands)

E. van den Neste (Eric); J.-L. André (Jean-Luc); Gastinne, T. (Thomas); A. Stamatoullas (Aspasia); C. Haioun (Corinne); Belhabri, A. (Amine); O. Reman (Oumédaly); O. Casasnovas (O.); H. Ghesquieres; G.E.G. Verhoef (Gregor); Claessen, M.-J. (Marie-José); H.A. Poirel (Hélène A); M.-C. Copin; Dubois, R. (Romain); P. Vandenberghe (Peter); Stoian, I.-A. (Ioanna-Andrea); Cottereau, A.S. (Anne S.); Bailly, S. (Sarah); L. Knoops (Laurent); F. Morschhauser (Frank)

2018-01-01

textabstractJAK2 constitutive activation/overexpression is common in classical Hodgkin lymphoma, and several cytokines stimulate Hodgkin lymphoma cells by recognizing JAK1-/JAK2-bound receptors. JAK blockade may thus be therapeutically beneficial in Hodgkin lymphoma. In this phase II study we

Electroneutral models for dynamic Poisson-Nernst-Planck systems

Science.gov (United States)

Song, Zilong; Cao, Xiulei; Huang, Huaxiong

2018-01-01

The Poisson-Nernst-Planck (PNP) system is a standard model for describing ion transport. In many applications, e.g., ions in biological tissues, the presence of thin boundary layers poses both modeling and computational challenges. In this paper, we derive simplified electroneutral (EN) models where the thin boundary layers are replaced by effective boundary conditions. There are two major advantages of EN models. First, it is much cheaper to solve them numerically. Second, EN models are easier to deal with compared to the original PNP system; therefore, it would also be easier to derive macroscopic models for cellular structures using EN models. Even though the approach used here is applicable to higher-dimensional cases, this paper mainly focuses on the one-dimensional system, including the general multi-ion case. Using systematic asymptotic analysis, we derive a variety of effective boundary conditions directly applicable to the EN system for the bulk region. This EN system can be solved directly and efficiently without computing the solution in the boundary layer. The derivation is based on matched asymptotics, and the key idea is to bring back higher-order contributions into the effective boundary conditions. For Dirichlet boundary conditions, the higher-order terms can be neglected and the classical results (continuity of electrochemical potential) are recovered. For flux boundary conditions, higher-order terms account for the accumulation of ions in boundary layer and neglecting them leads to physically incorrect solutions. To validate the EN model, numerical computations are carried out for several examples. Our results show that solving the EN model is much more efficient than the original PNP system. Implemented with the Hodgkin-Huxley model, the computational time for solving the EN model is significantly reduced without sacrificing the accuracy of the solution due to the fact that it allows for relatively large mesh and time-step sizes.

Hodgkin Lymphomas epidemiology

International Nuclear Information System (INIS)

Diaz, Carlos; Barroso, Maria; Alvarez, Julio; Sarmiento, Sofia; Diaz, Jose

2003-01-01

The interest of this study has been to learn the bio demographic characteristics of the Hodgkin lymphoma in our surrounding in accord with different clinical statistics that are considered of interest taken as references the results obtained in each on them. The clinical histories of the patients were evaluated retrospectively with diagnosis of Hodgkin, and registered in the national Institute of Oncology in Havana during the years 1980-1985 (group1) and the 1990-1995 (group 2). The sample was constituted by 242 patients (156 group 1, 86 group 2). The disease was slightly more frequent in males (1.3:1) in both groups. The biggest incidence fell upon the patients under 30 year of age with 74 (31%) in the group 1, and 41 (17%) group 2; followed by the group of patients between 30 and 49 years old with 24% in group 1 and 12 in group 2. The histological subtype most frequently found was the mixed cellularity 55% of the patients followed by nodular sclerosis in 32% clinical stage III was the most frequent with 138 patients (55%) the cervical adenopathy was the most consulted symptom referred by 199 (82%) of the patients. The ionizing radiation as only treatment were used in 115 patients (48%) while 80 (33%) were treated in conjunction with polychemotherapy, and in 40 (17%) polychemotherapy was used alone. A total of 204 (84%) patients showed complete remission when ended the initial treatment while 96 (40.9%) showed a relapse and 55 (62%) of them obtained a second CR. Until the last news, there are 196 (81%) alive patients and 43 (18%) dead. (The author)

Lattice Boltzmann model for high-order nonlinear partial differential equations.

Science.gov (United States)

Chai, Zhenhua; He, Nanzhong; Guo, Zhaoli; Shi, Baochang

2018-01-01

In this paper, a general lattice Boltzmann (LB) model is proposed for the high-order nonlinear partial differential equation with the form ∂_{t}ϕ+∑_{k=1}^{m}α_{k}∂_{x}^{k}Π_{k}(ϕ)=0 (1≤k≤m≤6), α_{k} are constant coefficients, Π_{k}(ϕ) are some known differential functions of ϕ. As some special cases of the high-order nonlinear partial differential equation, the classical (m)KdV equation, KdV-Burgers equation, K(n,n)-Burgers equation, Kuramoto-Sivashinsky equation, and Kawahara equation can be solved by the present LB model. Compared to the available LB models, the most distinct characteristic of the present model is to introduce some suitable auxiliary moments such that the correct moments of equilibrium distribution function can be achieved. In addition, we also conducted a detailed Chapman-Enskog analysis, and found that the high-order nonlinear partial differential equation can be correctly recovered from the proposed LB model. Finally, a large number of simulations are performed, and it is found that the numerical results agree with the analytical solutions, and usually the present model is also more accurate than the existing LB models [H. Lai and C. Ma, Sci. China Ser. G 52, 1053 (2009)1672-179910.1007/s11433-009-0149-3; H. Lai and C. Ma, Phys. A (Amsterdam) 388, 1405 (2009)PHYADX0378-437110.1016/j.physa.2009.01.005] for high-order nonlinear partial differential equations.

Lattice Boltzmann model for high-order nonlinear partial differential equations

Science.gov (United States)

Chai, Zhenhua; He, Nanzhong; Guo, Zhaoli; Shi, Baochang

2018-01-01

In this paper, a general lattice Boltzmann (LB) model is proposed for the high-order nonlinear partial differential equation with the form ∂tϕ +∑k=1mαk∂xkΠk(ϕ ) =0 (1 ≤k ≤m ≤6 ), αk are constant coefficients, Πk(ϕ ) are some known differential functions of ϕ . As some special cases of the high-order nonlinear partial differential equation, the classical (m)KdV equation, KdV-Burgers equation, K (n ,n ) -Burgers equation, Kuramoto-Sivashinsky equation, and Kawahara equation can be solved by the present LB model. Compared to the available LB models, the most distinct characteristic of the present model is to introduce some suitable auxiliary moments such that the correct moments of equilibrium distribution function can be achieved. In addition, we also conducted a detailed Chapman-Enskog analysis, and found that the high-order nonlinear partial differential equation can be correctly recovered from the proposed LB model. Finally, a large number of simulations are performed, and it is found that the numerical results agree with the analytical solutions, and usually the present model is also more accurate than the existing LB models [H. Lai and C. Ma, Sci. China Ser. G 52, 1053 (2009), 10.1007/s11433-009-0149-3; H. Lai and C. Ma, Phys. A (Amsterdam) 388, 1405 (2009), 10.1016/j.physa.2009.01.005] for high-order nonlinear partial differential equations.

Dynamic chromosomal rearrangements in Hodgkin's lymphoma are due to ongoing three-dimensional nuclear remodeling and breakage-bridge-fusion cycles.

Science.gov (United States)

Guffei, Amanda; Sarkar, Rahul; Klewes, Ludger; Righolt, Christiaan; Knecht, Hans; Mai, Sabine

2010-12-01

Hodgkin's lymphoma is characterized by the presence of mono-nucleated Hodgkin cells and bi- to multi-nucleated Reed-Sternberg cells. We have recently shown telomere dysfunction and aberrant synchronous/asynchronous cell divisions during the transition of Hodgkin cells to Reed-Sternberg cells.1 To determine whether overall changes in nuclear architecture affect genomic instability during the transition of Hodgkin cells to Reed-Sternberg cells, we investigated the nuclear organization of chromosomes in these cells. Three-dimensional fluorescent in situ hybridization revealed irregular nuclear positioning of individual chromosomes in Hodgkin cells and, more so, in Reed-Sternberg cells. We characterized an increasingly unequal distribution of chromosomes as mono-nucleated cells became multi-nucleated cells, some of which also contained chromosome-poor 'ghost' cell nuclei. Measurements of nuclear chromosome positions suggested chromosome overlaps in both types of cells. Spectral karyotyping then revealed both aneuploidy and complex chromosomal rearrangements: multiple breakage-bridge-fusion cycles were at the origin of the multiple rearranged chromosomes. This conclusion was challenged by super resolution three-dimensional structured illumination imaging of Hodgkin and Reed-Sternberg nuclei. Three-dimensional super resolution microscopy data documented inter-nuclear DNA bridges in multi-nucleated cells but not in mono-nucleated cells. These bridges consisted of chromatids and chromosomes shared by two Reed-Sternberg nuclei. The complexity of chromosomal rearrangements increased as Hodgkin cells developed into multi-nucleated cells, thus indicating tumor progression and evolution in Hodgkin's lymphoma, with Reed-Sternberg cells representing the highest complexity in chromosomal rearrangements in this disease. This is the first study to demonstrate nuclear remodeling and associated genomic instability leading to the generation of Reed-Sternberg cells of Hodgkin's lymphoma

Nonlinear interaction model of subsonic jet noise.

Science.gov (United States)

Sandham, Neil D; Salgado, Adriana M

2008-08-13

Noise generation in a subsonic round jet is studied by a simplified model, in which nonlinear interactions of spatially evolving instability modes lead to the radiation of sound. The spatial mode evolution is computed using linear parabolized stability equations. Nonlinear interactions are found on a mode-by-mode basis and the sound radiation characteristics are determined by solution of the Lilley-Goldstein equation. Since mode interactions are computed explicitly, it is possible to find their relative importance for sound radiation. The method is applied to a single stream jet for which experimental data are available. The model gives Strouhal numbers of 0.45 for the most amplified waves in the jet and 0.19 for the dominant sound radiation. While in near field axisymmetric and the first azimuthal modes are both important, far-field sound is predominantly axisymmetric. These results are in close correspondence with experiment, suggesting that the simplified model is capturing at least some of the important mechanisms of subsonic jet noise.

Nonlinear price impact from linear models

Science.gov (United States)

Patzelt, Felix; Bouchaud, Jean-Philippe

2017-12-01

The impact of trades on asset prices is a crucial aspect of market dynamics for academics, regulators, and practitioners alike. Recently, universal and highly nonlinear master curves were observed for price impacts aggregated on all intra-day scales (Patzelt and Bouchaud 2017 arXiv:1706.04163). Here we investigate how well these curves, their scaling, and the underlying return dynamics are captured by linear ‘propagator’ models. We find that the classification of trades as price-changing versus non-price-changing can explain the price impact nonlinearities and short-term return dynamics to a very high degree. The explanatory power provided by the change indicator in addition to the order sign history increases with increasing tick size. To obtain these results, several long-standing technical issues for model calibration and testing are addressed. We present new spectral estimators for two- and three-point cross-correlations, removing the need for previously used approximations. We also show when calibration is unbiased and how to accurately reveal previously overlooked biases. Therefore, our results contribute significantly to understanding both recent empirical results and the properties of a popular class of impact models.

Modeling and nonlinear heading control for sailing yachts

DEFF Research Database (Denmark)

Xiao, Lin; Jouffroy, Jerome

2014-01-01

This paper presents a study on the development and testing of a model-based heading controller for a sailing yacht. Using Fossen’s compact notation for marine vehicles, we first describe a nonlinear four-degree-of-freedom (DOF) dynamic model for a sailing yacht, including roll. Our model also...

Modeling and nonlinear heading control for sailing yachts

DEFF Research Database (Denmark)

Xiao, Lin; Jouffroy, Jerome

2011-01-01

This paper presents a study on the development and testing of a model-based heading controller for a sailing yacht. Using Fossen's compact notation for marine vehicles, we first describe a nonlinear 4-DOF dynamic model for a sailing yacht, including roll. Starting from this model, we then design...

Recurrence of non-Hodgkin's lymphoma

International Nuclear Information System (INIS)

Watanabe, Toshikazu; Kiyono, Kunihiro; Niibe, Hideo; Horiuchi, Junichi; Kaneta, Koichi; Morita, Kozo; Masaki, Norie; Hayabuchi, Naofumi.

1988-01-01

563 patients with Stage I and II non-Hodgkin's lymphoma were treated by radiotherapy. 34 recurrences that occured after 3 years from initial treatment were seen in those patients. 15 (44 %) of 34 recurrences occured after 5 years. 20 patients (59 %) had remission by re-treatment, and 13 (38 %) survived more than 2 years. 20 (59 %) of recurrences were seen on head and neck lesions and superficial lymph nodes. (author)

Recurrence of non-Hodgkin's lymphoma

International Nuclear Information System (INIS)

Watanabe, Toshikazu; Oguchi, Masahiko; Niibe, Hideo; Horiuchi, Junichi; Kaneta, Koichi; Morita, Kozo; Masaki, Norie; Hayabuchi, Naofumi.

1988-01-01

From 1972 to 1982, 563 patients with Stage I and II non-Hodgkin's lymphoma received radiation therapy in the department of radiology which belongs to the JLRTS group. Local control failures were seen in only 5 cases (0.9 %). The regional recurrences were found in 30 cases (5 %). 17 of recurrences occured during the first 5 years. 17 cases had remissions again, and 5 cases had 5 year survivals. (author)

Null Controllability of a Nonlinear Dissipative System and Application to the Detection of the Incomplete Parameter for a Nonlinear Population Dynamics Model

Directory of Open Access Journals (Sweden)

Yacouba Simporé

2016-01-01

Full Text Available We first prove a null controllability result for a nonlinear system derived from a nonlinear population dynamics model. In order to tackle the controllability problem we use an adapted Carleman inequality. Next we consider the nonlinear population dynamics model with a source term called the pollution term. In order to obtain information on the pollution term we use the method of sentinel.

Mucosal bridges of the upper esophagus after radiotherapy for Hodgkin's disease

International Nuclear Information System (INIS)

Papazian, A.; Capron, J.P.; Ducroix, J.P.; Dupas, J.L.; Quenum, C.; Besson, P.

1983-01-01

A 47-yr-old man developed dysphagia 4 yr after mediastinal radiotherapy for Hodgkin's disease. X-ray series, fiberoptic endoscopy, and computerized transverse tomography showed mucosal bridges in the upper esophagus. Histologically, these bridges were constituted from normal epithelium overlying a chronic inflammatory lamina propria, without evidence of Hodgkin's disease recurrence or of squamous cell carcinoma. Swallowing was improved by endoscopic electrocoagulation and Eder-Puestow dilatations. Several arguments favor the hypothesis that these mucosal bridges were the late sequelae of radiation esophagitis

Nonlinear Dynamic Model of PMBLDC Motor Considering Core Losses

DEFF Research Database (Denmark)

Fasil, Muhammed; Mijatovic, Nenad; Jensen, Bogi Bech

2017-01-01

The phase variable model is used commonly when simulating a motor drive system with a three-phase permanent magnet brushless DC (PMBLDC) motor. The phase variable model neglects core losses and this affects its accuracy when modelling fractional-slot machines. The inaccuracy of phase variable mod...... on the detailed analysis of the flux path and the variation of flux in different components of the machine. A prototype of fractional slot axial flux PMBLDC in-wheel motor is used to assess the proposed nonlinear dynamic model....... of fractional-slot machines can be attributed to considerable armature flux harmonics, which causes an increased core loss. This study proposes a nonlinear phase variable model of PMBLDC motor that considers the core losses induced in the stator and the rotor. The core loss model is developed based...

Non-linear scaling of a musculoskeletal model of the lower limb using statistical shape models.

Science.gov (United States)

Nolte, Daniel; Tsang, Chui Kit; Zhang, Kai Yu; Ding, Ziyun; Kedgley, Angela E; Bull, Anthony M J

2016-10-03

Accurate muscle geometry for musculoskeletal models is important to enable accurate subject-specific simulations. Commonly, linear scaling is used to obtain individualised muscle geometry. More advanced methods include non-linear scaling using segmented bone surfaces and manual or semi-automatic digitisation of muscle paths from medical images. In this study, a new scaling method combining non-linear scaling with reconstructions of bone surfaces using statistical shape modelling is presented. Statistical Shape Models (SSMs) of femur and tibia/fibula were used to reconstruct bone surfaces of nine subjects. Reference models were created by morphing manually digitised muscle paths to mean shapes of the SSMs using non-linear transformations and inter-subject variability was calculated. Subject-specific models of muscle attachment and via points were created from three reference models. The accuracy was evaluated by calculating the differences between the scaled and manually digitised models. The points defining the muscle paths showed large inter-subject variability at the thigh and shank - up to 26mm; this was found to limit the accuracy of all studied scaling methods. Errors for the subject-specific muscle point reconstructions of the thigh could be decreased by 9% to 20% by using the non-linear scaling compared to a typical linear scaling method. We conclude that the proposed non-linear scaling method is more accurate than linear scaling methods. Thus, when combined with the ability to reconstruct bone surfaces from incomplete or scattered geometry data using statistical shape models our proposed method is an alternative to linear scaling methods. Copyright © 2016 The Author. Published by Elsevier Ltd.. All rights reserved.

Applicability of linear and non-linear potential flow models on a Wavestar float

DEFF Research Database (Denmark)

Bozonnet, Pauline; Dupin, Victor; Tona, Paolino

2017-01-01

as a model based on non-linear potential flow theory and weakscatterer hypothesis are successively considered. Simple tests, such as dip tests, decay tests and captive tests enable to highlight the improvements obtained with the introduction of nonlinearities. Float motion under wave actions and without...... control action, limited to small amplitude motion with a single float, is well predicted by the numerical models, including the linear one. Still, float velocity is better predicted by accounting for non-linear hydrostatic and Froude-Krylov forces.......Numerical models based on potential flow theory, including different types of nonlinearities are compared and validated against experimental data for the Wavestar wave energy converter technology. Exact resolution of the rotational motion, non-linear hydrostatic and Froude-Krylov forces as well...

Nonlinear model predictive control of a wave energy converter based on differential flatness parameterisation

Science.gov (United States)

Li, Guang

2017-01-01

This paper presents a fast constrained optimization approach, which is tailored for nonlinear model predictive control of wave energy converters (WEC). The advantage of this approach relies on its exploitation of the differential flatness of the WEC model. This can reduce the dimension of the resulting nonlinear programming problem (NLP) derived from the continuous constrained optimal control of WEC using pseudospectral method. The alleviation of computational burden using this approach helps to promote an economic implementation of nonlinear model predictive control strategy for WEC control problems. The method is applicable to nonlinear WEC models, nonconvex objective functions and nonlinear constraints, which are commonly encountered in WEC control problems. Numerical simulations demonstrate the efficacy of this approach.

Model Predictive Control of a Nonlinear System with Known Scheduling Variable

DEFF Research Database (Denmark)

Mirzaei, Mahmood; Poulsen, Niels Kjølstad; Niemann, Hans Henrik

2012-01-01

Model predictive control (MPC) of a class of nonlinear systems is considered in this paper. We will use Linear Parameter Varying (LPV) model of the nonlinear system. By taking the advantage of having future values of the scheduling variable, we will simplify state prediction. Consequently...... the control problem of the nonlinear system is simplied into a quadratic programming. Wind turbine is chosen as the case study and we choose wind speed as the scheduling variable. Wind speed is measurable ahead of the turbine, therefore the scheduling variable is known for the entire prediction horizon....

Multi-atom Jaynes-Cummings model with nonlinear effects

International Nuclear Information System (INIS)

Aleixo, Armando Nazareno Faria; Balantekin, Akif Baha; Ribeiro, Marco Antonio Candido

2001-01-01

The standard Jaynes-Cummings (JC) model and its extensions, normally used in quantum optics, idealizes the interaction of matter with electromagnetic radiation by a simple Hamiltonian of a two-level atom coupled to a single bosonic mode. This Hamiltonian has a fundamental importance to the field of quantum optics and it is a central ingredient in the quantized description of any optical system involving the interaction between light and atoms. The JC Hamiltonian defines a molecule, a composite system formed from the coupling of a two-state system and a quantized harmonic oscillator. For this Hamiltonian, mostly the single-particle situation has been studied. This model can also be extended for the situation where one has N two-level systems, which interact only with the electromagnetic radiation. In this case the effects of the spatial distribution of the particles it is not taken into account and the spin angular momentum S-circumflex i of each particle contributes to form a total angular momentum J-circumflex of the system. When one considers the effects due to the spatial variation in the field intensity in a nonlinear medium it is necessary to further add a Kerr term to the standard JC Hamiltonian. This kind of nonlinear JC Hamiltonian is used in the study of micro masers. Another nonlinear variant of the JC model takes the coupling between matter and the radiation to depend on the intensity of the electromagnetic field. This model is interesting since this kind of interaction means that effectively the coupling is proportional to the amplitude of the field representing a very simple case of a nonlinear interaction corresponding to a more realistic physical situation. In this work we solve exactly the problem of the interaction of a N two-level atoms with an electromagnetic radiation when nonlinear effects due to the spatial variation in the field intensity in a nonlinear Kerr medium and the dependence on the intensity of the electromagnetic field on the matter

Solitary wave and periodic wave solutions for Burgers, Fisher ...

Indian Academy of Sciences (India)

The generalized (G′/G)-expansion method; Burgers equation; Fisher's equation; ... the travelling wave solutions plays an important role in nonlinear sciences. ... Burgers, Fisher, Huxley equations and combined forms of these equations will ...

Late effects after treatment for Hodgkin lymphoma

NARCIS (Netherlands)

Daniëls, Laurien Aletta

2014-01-01

Although modern treatment strategies have made Hodgkin Lymphoma (HL) a highly curable disease, there is a life-long increased risk of morbidity and mortality due to treatment. Over time it has become increasingly evident that the historically used extensive treatment fields can potentially lead to

Nonlinear dynamic mechanism of vocal tremor from voice analysis and model simulations

Science.gov (United States)

Zhang, Yu; Jiang, Jack J.

2008-09-01

Nonlinear dynamic analysis and model simulations are used to study the nonlinear dynamic characteristics of vocal folds with vocal tremor, which can typically be characterized by low-frequency modulation and aperiodicity. Tremor voices from patients with disorders such as paresis, Parkinson's disease, hyperfunction, and adductor spasmodic dysphonia show low-dimensional characteristics, differing from random noise. Correlation dimension analysis statistically distinguishes tremor voices from normal voices. Furthermore, a nonlinear tremor model is proposed to study the vibrations of the vocal folds with vocal tremor. Fractal dimensions and positive Lyapunov exponents demonstrate the evidence of chaos in the tremor model, where amplitude and frequency play important roles in governing vocal fold dynamics. Nonlinear dynamic voice analysis and vocal fold modeling may provide a useful set of tools for understanding the dynamic mechanism of vocal tremor in patients with laryngeal diseases.

Nonlinear model updating applied to the IMAC XXXII Round Robin benchmark system

Science.gov (United States)

Kurt, Mehmet; Moore, Keegan J.; Eriten, Melih; McFarland, D. Michael; Bergman, Lawrence A.; Vakakis, Alexander F.

2017-05-01

We consider the application of a new nonlinear model updating strategy to a computational benchmark system. The approach relies on analyzing system response time series in the frequency-energy domain by constructing both Hamiltonian and forced and damped frequency-energy plots (FEPs). The system parameters are then characterized and updated by matching the backbone branches of the FEPs with the frequency-energy wavelet transforms of experimental and/or computational time series. The main advantage of this method is that no nonlinearity model is assumed a priori, and the system model is updated solely based on simulation and/or experimental measured time series. By matching the frequency-energy plots of the benchmark system and its reduced-order model, we show that we are able to retrieve the global strongly nonlinear dynamics in the frequency and energy ranges of interest, identify bifurcations, characterize local nonlinearities, and accurately reconstruct time series. We apply the proposed methodology to a benchmark problem, which was posed to the system identification community prior to the IMAC XXXII (2014) and XXXIII (2015) Conferences as a "Round Robin Exercise on Nonlinear System Identification". We show that we are able to identify the parameters of the non-linear element in the problem with a priori knowledge about its position.

Gallium scan in recurrent Hodgkin's disease in children

International Nuclear Information System (INIS)

Yeh, S.D.; Benua, R.S.; Tan, C.T.

1979-01-01

In 18 of 88 children with biopsy proven and previously untreated Hodgkin's disease, recurrence developed during a period from four to 53 months after therapy (median period, 22 months). In 16 patients in whom gallium scans were performed, 21 positive gallium scans were obtained during 26 episodes of recurrence. Abnormalities were noted in half of them during a period from one to 10 months prior to physical, laboratory, radiographic or histologic confirmation of recurrence (median period about 5 months). We have concluded that the gallium scan is very useful in initial workup and is sensitive in detecting early recurrence in children with Hodgkin's disease. Such scans are indicated when there is clinical suspicion of recurrence, when other modalities are unavailable or when the results of other studies are equivocal

Nonlinear model of a rotating hub-beams structure: Equations of motion

Science.gov (United States)

Warminski, Jerzy

2018-01-01

Dynamics of a rotating structure composed of a rigid hub and flexible beams is presented in the paper. A nonlinear model of a beam takes into account bending, extension and nonlinear curvature. The influence of geometric nonlinearity and nonconstant angular velocity on dynamics of the rotating structure is presented. The exact equations of motion and associated boundary conditions are derived on the basis of the Hamilton's principle. The simplification of the exact nonlinear mathematical model is proposed taking into account the second order approximation. The reduced partial differential equations of motion together with associated boundary conditions can be used to study natural or forced vibrations of a rotating structure considering constant or nonconstant angular speed of a rigid hub and an arbitrary number of flexible blades.

Studies of phase return map and symbolic dynamics in a periodically driven Hodgkin—Huxley neuron

International Nuclear Information System (INIS)

Ding Jiong; Zhang Hong; Tong Qin-Ye; Chen Zhuo

2014-01-01

How neuronal spike trains encode external information is a hot topic in neurodynamics studies. In this paper, we investigate the dynamical states of the Hodgkin—Huxley neuron under periodic forcing. Depending on the parameters of the stimulus, the neuron exhibits periodic, quasiperiodic and chaotic spike trains. In order to analyze these spike trains quantitatively, we use the phase return map to describe the dynamical behavior on a one-dimensional (1D) map. According to the monotonicity or discontinuous point of the 1D map, the spike trains are transformed into symbolic sequences by implementing a coarse-grained algorithm — symbolic dynamics. Based on the ordering rules of symbolic dynamics, the parameters of the external stimulus can be measured in high resolution with finite length symbolic sequences. A reasonable explanation for why the nervous system can discriminate or cognize the small change of the external signals in a short time is also presented. (general)

Predicting the past: ancient eclipses and Airy, Newcomb, and Huxley on the authority of science.

Science.gov (United States)

Stanley, Matthew

2012-06-01

Greek historical accounts of ancient eclipses were an important, if peculiar, focus of scientific attention in the nineteenth century. Victorian-era astronomers tried to correct the classical histories using scientific methods, then used those histories as data with which to calibrate their lunar theories, then rejected the histories as having any relevance at all. The specific dating of these eclipses--apparently a simple exercise in celestial mechanics--became bound up with tensions between scientific and humanistic approaches to the past as well as with wider social debates over the power and authority of science in general. The major figures discussed here, including G. B. Airy, Simon Newcomb, and T. H. Huxley, argued that the critical question was whether science could speak authoritatively about the past. To them, the ability of science to talk about the past indicated its power to talk about the future; it was also the fulcrum of fierce boundary disputes among science, history, and religion.

Neural-Based Compensation of Nonlinearities in an Airplane Longitudinal Model with Dynamic-Inversion Control

Directory of Open Access Journals (Sweden)

YanBin Liu

2017-01-01

Full Text Available The inversion design approach is a very useful tool for the complex multiple-input-multiple-output nonlinear systems to implement the decoupling control goal, such as the airplane model and spacecraft model. In this work, the flight control law is proposed using the neural-based inversion design method associated with the nonlinear compensation for a general longitudinal model of the airplane. First, the nonlinear mathematic model is converted to the equivalent linear model based on the feedback linearization theory. Then, the flight control law integrated with this inversion model is developed to stabilize the nonlinear system and relieve the coupling effect. Afterwards, the inversion control combined with the neural network and nonlinear portion is presented to improve the transient performance and attenuate the uncertain effects on both external disturbances and model errors. Finally, the simulation results demonstrate the effectiveness of this controller.

Hodgkin's disease following thorium dioxide angiography

Energy Technology Data Exchange (ETDEWEB)

Gotlieb, A I; Kirk, M E [McGill Univ., Montreal, Quebec (Canada). Dept. of Pathology; Hutchison, J L [Montreal General Hospital, Quebec (Canada)

1976-09-04

Hodgkin's disease occurred in a 53-year-old man who, 25 years previously, had undergone cerebral angiography, for which thorium dioxide suspension (Thorotrast) was used. Deposits of thorium dioxide were noted in reticuloendothelial cells in various locations. An association between thorium dioxide administration and the subsequent development of malignant tumours and neoplastic hematologic disorders has previously been reported.

Nonlinear optical model for strip plasmonic waveguides

DEFF Research Database (Denmark)

Lysenko, Oleg; Bache, Morten; Lavrinenko, Andrei

2016-01-01

This paper presents a theoretical model of nonlinear optical properties for strip plasmonic waveguides. The particular waveguides geometry that we investigate contains a gold core, adhesion layers, and silicon dioxide cladding. It is shown that the third-order susceptibility of the gold core...... significantly depends on the layer thickness and has the dominant contribution to the effective third-order susceptibility of the long-range plasmon polariton mode. This results in two nonlinear optical effects in plasmonic waveguides, which we experimentally observed and reported in [Opt. Lett. 41, 317 (2016...... approaches. (C) 2016 Optical Society of America...

Sphaleron in a non-linear sigma model

International Nuclear Information System (INIS)

Sogo, Kiyoshi; Fujimoto, Yasushi.

1989-08-01

We present an exact classical saddle point solution in a non-linear sigma model. It has a topological charge 1/2 and mediates the vacuum transition. The quantum fluctuations and the transition rate are also examined. (author)

Studies of biaxial mechanical properties and nonlinear finite element modeling of skin.

Science.gov (United States)

Shang, Xituan; Yen, Michael R T; Gaber, M Waleed

2010-06-01

The objective of this research is to conduct mechanical property studies of skin from two individual but potentially connected aspects. One is to determine the mechanical properties of the skin experimentally by biaxial tests, and the other is to use the finite element method to model the skin properties. Dynamic biaxial tests were performed on 16 pieces of abdominal skin specimen from rats. Typical biaxial stress-strain responses show that skin possesses anisotropy, nonlinearity and hysteresis. To describe the stress-strain relationship in forms of strain energy function, the material constants of each specimen were obtained and the results show a high correlation between theory and experiments. Based on the experimental results, a finite element model of skin was built to model the skin's special properties including anisotropy and nonlinearity. This model was based on Arruda and Boyce's eight-chain model and Bischoff et al.'s finite element model of skin. The simulation results show that the isotropic, nonlinear eight-chain model could predict the skin's anisotropic and nonlinear responses to biaxial loading by the presence of an anisotropic prestress state.

Reproducing the nonlinear dynamic behavior of a structured beam with a generalized continuum model

Science.gov (United States)

Vila, J.; Fernández-Sáez, J.; Zaera, R.

2018-04-01

In this paper we study the coupled axial-transverse nonlinear vibrations of a kind of one dimensional structured solids by application of the so called Inertia Gradient Nonlinear continuum model. To show the accuracy of this axiomatic model, previously proposed by the authors, its predictions are compared with numeric results from a previously defined finite discrete chain of lumped masses and springs, for several number of particles. A continualization of the discrete model equations based on Taylor series allowed us to set equivalent values of the mechanical properties in both discrete and axiomatic continuum models. Contrary to the classical continuum model, the inertia gradient nonlinear continuum model used herein is able to capture scale effects, which arise for modes in which the wavelength is comparable to the characteristic distance of the structured solid. The main conclusion of the work is that the proposed generalized continuum model captures the scale effects in both linear and nonlinear regimes, reproducing the behavior of the 1D nonlinear discrete model adequately.

Static aeroelastic analysis including geometric nonlinearities based on reduced order model

Directory of Open Access Journals (Sweden)

Changchuan Xie

2017-04-01

Full Text Available This paper describes a method proposed for modeling large deflection of aircraft in nonlinear aeroelastic analysis by developing reduced order model (ROM. The method is applied for solving the static aeroelastic and static aeroelastic trim problems of flexible aircraft containing geometric nonlinearities; meanwhile, the non-planar effects of aerodynamics and follower force effect have been considered. ROMs are computational inexpensive mathematical representations compared to traditional nonlinear finite element method (FEM especially in aeroelastic solutions. The approach for structure modeling presented here is on the basis of combined modal/finite element (MFE method that characterizes the stiffness nonlinearities and we apply that structure modeling method as ROM to aeroelastic analysis. Moreover, the non-planar aerodynamic force is computed by the non-planar vortex lattice method (VLM. Structure and aerodynamics can be coupled with the surface spline method. The results show that both of the static aeroelastic analysis and trim analysis of aircraft based on structure ROM can achieve a good agreement compared to analysis based on the FEM and experimental result.

Non-linear characterisation of the physical model of an ancient masonry bridge

International Nuclear Information System (INIS)

Fragonara, L Zanotti; Ceravolo, R; Matta, E; Quattrone, A; De Stefano, A; Pecorelli, M

2012-01-01

This paper presents the non-linear investigations carried out on a scaled model of a two-span masonry arch bridge. The model has been built in order to study the effect of the central pile settlement due to riverbank erosion. Progressive damage was induced in several steps by applying increasing settlements at the central pier. For each settlement step, harmonic shaker tests were conducted under different excitation levels, this allowing for the non-linear identification of the progressively damaged system. The shaker tests have been performed at resonance with the modal frequency of the structure, which were determined from a previous linear identification. Estimated non-linearity parameters, which result from the systematic application of restoring force based identification algorithms, can corroborate models to be used in the reassessment of existing structures. The method used for non-linear identification allows monitoring the evolution of non-linear parameters or indicators which can be used in damage and safety assessment.

Imaging of supradiaphragmatic manifestations of extranodal nonHodgkin's lymphoma

International Nuclear Information System (INIS)

Cohnen, M.; Saleh, A.; Engelbrecht, V.; Moedder, U.; Germing, U.

2002-01-01

Malignant lymphomas are differentiated into Hodgkin's and non-Hodgkin's-lymphoma (NHL). The following article discusses the imaging of extranodal NHL in supradiaphragmatic localizations. Lymphoma can affect nearly all tissues, and represent a rare entity as primary extranodal NHL. A secondary involvement of non-nodal tissue as consequence of a generalized lymphoproliferative disease is more common,and may be seen as well in HIV-positive patients defining AIDS. As extranodal lymphoma mimick the radiologic appearance of other malignant tumors, direct diagnosis without histologic analysis is often impossible. The article describes typical manifestations of lymphoma of the lungs, the head and neck area including the large glands, and rare localizations as the heart or the breast. (orig.) [de

Model reduction of systems with localized nonlinearities.

Energy Technology Data Exchange (ETDEWEB)

Segalman, Daniel Joseph

2006-03-01

An LDRD funded approach to development of reduced order models for systems with local nonlinearities is presented. This method is particularly useful for problems of structural dynamics, but has potential application in other fields. The key elements of this approach are (1) employment of eigen modes of a reference linear system, (2) incorporation of basis functions with an appropriate discontinuity at the location of the nonlinearity. Galerkin solution using the above combination of basis functions appears to capture the dynamics of the system with a small basis set. For problems involving small amplitude dynamics, the addition of discontinuous (joint) modes appears to capture the nonlinear mechanics correctly while preserving the modal form of the predictions. For problems involving large amplitude dynamics of realistic joint models (macro-slip), the use of appropriate joint modes along with sufficient basis eigen modes to capture the frequencies of the system greatly enhances convergence, though the modal nature the result is lost. Also observed is that when joint modes are used in conjunction with a small number of elastic eigen modes in problems of macro-slip of realistic joint models, the resulting predictions are very similar to those of the full solution when seen through a low pass filter. This has significance both in terms of greatly reducing the number of degrees of freedom of the problem and in terms of facilitating the use of much larger time steps.

Research on nonlinear stochastic dynamical price model

International Nuclear Information System (INIS)

Li Jiaorui; Xu Wei; Xie Wenxian; Ren Zhengzheng

2008-01-01

In consideration of many uncertain factors existing in economic system, nonlinear stochastic dynamical price model which is subjected to Gaussian white noise excitation is proposed based on deterministic model. One-dimensional averaged Ito stochastic differential equation for the model is derived by using the stochastic averaging method, and applied to investigate the stability of the trivial solution and the first-passage failure of the stochastic price model. The stochastic price model and the methods presented in this paper are verified by numerical studies

A Comparative Study Of Stock Price Forecasting Using Nonlinear Models

Directory of Open Access Journals (Sweden)

Diteboho Xaba

2017-03-01

Full Text Available This study compared the in-sample forecasting accuracy of three forecasting nonlinear models namely: the Smooth Transition Regression (STR model, the Threshold Autoregressive (TAR model and the Markov-switching Autoregressive (MS-AR model. Nonlinearity tests were used to confirm the validity of the assumptions of the study. The study used model selection criteria, SBC to select the optimal lag order and for the selection of appropriate models. The Mean Square Error (MSE, Mean Absolute Error (MAE and Root Mean Square Error (RMSE served as the error measures in evaluating the forecasting ability of the models. The MS-AR models proved to perform well with lower error measures as compared to LSTR and TAR models in most cases.

Frequent alteration of MDM2 and p53 in the molecular progression of recurring non-Hodgkin's lymphoma

DEFF Research Database (Denmark)

Møller, Michael Boe; Nielsen, O; Pedersen, Niels Tinggaard

2002-01-01

-Hodgkin's lymphoma. METHODS AND RESULTS: We have analysed sequential biopsies from 42 non-Hodgkin's lymphoma patients immunohistochemically for p53 alterations (based on p53 and p21Waf1 expression), as well as for expression of MDM2, p27Kip1 and cyclin D3. Relapse of follicle centre lymphoma was associated with p53...... alterations as 5/6 (83%) follicle centre lymphomas with normal p53 at diagnosis showed p53 alterations at relapse. Of these cases, three showed transformation to diffuse large B-cell lymphoma. p53 alteration was also associated with relapse of de novo diffuse large B-cell lymphoma and T-cell non......-Hodgkin's lymphoma, as 2/5 (40%) diffuse large B-cell lymphomas and 3/9 (33%) T-cell non-Hodgkin's lymphomas with normal p53 at diagnosis showed p53 alterations at relapse. No indolent non-Hodgkin's lymphoma case showed MDM2 over-expression at diagnosis, whereas 4/5 (80%) transformed diffuse large B-cell lymphomas...

Model Updating Nonlinear System Identification Toolbox, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — ZONA Technology (ZONA) proposes to develop an enhanced model updating nonlinear system identification (MUNSID) methodology that utilizes flight data with...

Late cardiotoxicity after treatment for Hodgkin lymphoma

DEFF Research Database (Denmark)

Aleman, Berthe M P; van den Belt-Dusebout, Alexandra W; De Bruin, Marie L

2007-01-01

We assessed cardiovascular disease (CVD) incidence in 1474 survivors of Hodgkin lymphoma (HL) younger than 41 years at treatment (1965-1995). Multivariable Cox regression and competing risk analyses were used to quantify treatment effects on CVD risk. After a median follow-up of 18.7 years, risks...

Symbolic-computation study of the perturbed nonlinear Schrodinger model in inhomogeneous optical fibers

International Nuclear Information System (INIS)

Tian Bo; Gao Yitian

2005-01-01

A realistic, inhomogeneous fiber in the optical communication systems can be described by the perturbed nonlinear Schrodinger model (also named as the normalized nonlinear Schrodinger model with periodically varying coefficients, dispersion managed nonlinear Schrodinger model or nonlinear Schrodinger model with variable coefficients). Hereby, we extend to this model a direct method, perform symbolic computation and obtain two families of the exact, analytic bright-solitonic solutions, with or without the chirp respectively. The parameters addressed include the shape of the bright soliton, soliton amplitude, inverse width of the soliton, chirp, frequency, center of the soliton and center of the phase of the soliton. Of optical and physical interests, we discuss some previously-published special cases of our solutions. Those solutions could help the future studies on the optical communication systems. ms

Model-free inference of direct network interactions from nonlinear collective dynamics.

Science.gov (United States)

Casadiego, Jose; Nitzan, Mor; Hallerberg, Sarah; Timme, Marc

2017-12-19

The topology of interactions in network dynamical systems fundamentally underlies their function. Accelerating technological progress creates massively available data about collective nonlinear dynamics in physical, biological, and technological systems. Detecting direct interaction patterns from those dynamics still constitutes a major open problem. In particular, current nonlinear dynamics approaches mostly require to know a priori a model of the (often high dimensional) system dynamics. Here we develop a model-independent framework for inferring direct interactions solely from recording the nonlinear collective dynamics generated. Introducing an explicit dependency matrix in combination with a block-orthogonal regression algorithm, the approach works reliably across many dynamical regimes, including transient dynamics toward steady states, periodic and non-periodic dynamics, and chaos. Together with its capabilities to reveal network (two point) as well as hypernetwork (e.g., three point) interactions, this framework may thus open up nonlinear dynamics options of inferring direct interaction patterns across systems where no model is known.

A non-linear model of economic production processes

Science.gov (United States)

Ponzi, A.; Yasutomi, A.; Kaneko, K.

2003-06-01

We present a new two phase model of economic production processes which is a non-linear dynamical version of von Neumann's neoclassical model of production, including a market price-setting phase as well as a production phase. The rate of an economic production process is observed, for the first time, to depend on the minimum of its input supplies. This creates highly non-linear supply and demand dynamics. By numerical simulation, production networks are shown to become unstable when the ratio of different products to total processes increases. This provides some insight into observed stability of competitive capitalist economies in comparison to monopolistic economies. Capitalist economies are also shown to have low unemployment.

Composite Lymphoma : EBV-positive Classic Hodgkin Lymphoma and Peripheral T-cell Lymphoma A Case Report

NARCIS (Netherlands)

Gualco, Gabriela; Chioato, Lucimara; Van Den Berg, Anke; Weiss, Lawrence M.; Bacchi, Carlos E.

Composite lymphomas are rare and defined as hematopoietic neoplasms with more than I malignant lymphomatous clone showing different phenotypic features. Of all possible combinations between non-Hodgkin lymphomas, B cell or T cell, and Hodgkin lymphoma, the least frequent are the ones combining

A nonlinear complementarity approach for the national energy modeling system

International Nuclear Information System (INIS)

Gabriel, S.A.; Kydes, A.S.

1995-01-01

The National Energy Modeling System (NEMS) is a large-scale mathematical model that computes equilibrium fuel prices and quantities in the U.S. energy sector. At present, to generate these equilibrium values, NEMS sequentially solves a collection of linear programs and nonlinear equations. The NEMS solution procedure then incorporates the solutions of these linear programs and nonlinear equations in a nonlinear Gauss-Seidel approach. The authors describe how the current version of NEMS can be formulated as a particular nonlinear complementarity problem (NCP), thereby possibly avoiding current convergence problems. In addition, they show that the NCP format is equally valid for a more general form of NEMS. They also describe several promising approaches for solving the NCP form of NEMS based on recent Newton type methods for general NCPs. These approaches share the feature of needing to solve their direction-finding subproblems only approximately. Hence, they can effectively exploit the sparsity inherent in the NEMS NCP

Nonlinear transfer of elements from soil to plants: impact on radioecological modeling

Energy Technology Data Exchange (ETDEWEB)

Tuovinen, Tiina S.; Kolehmainen, Mikko; Roivainen, Paeivi; Kumlin, Timo; Makkonen, Sari; Holopainen, Toini; Juutilainen, Jukka [University of Eastern Finland, Department of Environmental and Biological Sciences, P.O. Box 1627, Kuopio (Finland)

2016-08-15

In radioecology, transfer of radionuclides from soil to plants is typically described by a concentration ratio (CR), which assumes linearity of transfer with soil concentration. Nonlinear uptake is evidenced in many studies, but it is unclear how it should be taken into account in radioecological modeling. In this study, a conventional CR-based linear model, a nonlinear model derived from observed uptake into plants, and a new simple model based on the observation that nonlinear uptake leads to a practically constant concentration in plant tissues are compared. The three models were used to predict transfer of {sup 234}U, {sup 59}Ni and {sup 210}Pb into spruce needles. The predictions of the nonlinear and the new model were essentially similar. In contrast, plant radionuclide concentration was underestimated by the linear model when the total element concentration in soil was relatively low, but within the range commonly observed in nature. It is concluded that the linear modeling could easily be replaced by a new approach that more realistically reflects the true processes involved in the uptake of elements into plants. The new modeling approach does not increase the complexity of modeling in comparison with CR-based linear models, and data needed for model parameters (element concentrations) are widely available. (orig.)

Treatment of Hodgkin's lymphoma

International Nuclear Information System (INIS)

Petrov, M.

1986-01-01

The data pertinent to 101 patients with Hodgkin's disease who had been subjected to splenectomy and combined radiation therapy and chemotherapy are analyzed. The efficacy of the treatment was relatively dependent on the initial localization and the degree of the generalization and appresiveness of the disease. Acceleration of the disease gene realization stemmed from totally deranged antitumor immunity. The modern therapeutic remedies have reached the peak of their potentialities. This prompt the necessity of the search for new, still unknown biological methods, permitting the attainment of a more complete demalignancy

Landau fluid model for weakly nonlinear dispersive magnetohydrodynamics

International Nuclear Information System (INIS)

Passot, T.; Sulem, P. L.

2005-01-01

In may astrophysical plasmas such as the solar wind, the terrestrial magnetosphere, or in the interstellar medium at small enough scales, collisions are negligible. When interested in the large-scale dynamics, a hydrodynamic approach is advantageous not only because its numerical simulations is easier than of the full Vlasov-Maxwell equations, but also because it provides a deep understanding of cross-scale nonlinear couplings. It is thus of great interest to construct fluid models that extended the classical magnetohydrodynamic (MHD) equations to collisionless situations. Two ingredients need to be included in such a model to capture the main kinetic effects: finite Larmor radius (FLR) corrections and Landau damping, the only fluid-particle resonance that can affect large scales and can be modeled in a relatively simple way. The Modelization of Landau damping in a fluid formalism is hardly possible in the framework of a systematic asymptotic expansion and was addressed mainly by means of parameter fitting in a linearized setting. We introduced a similar Landau fluid model but, that has the advantage of taking dispersive effects into account. This model properly describes dispersive MHD waves in quasi-parallel propagation. Since, by construction, the system correctly reproduces their linear dynamics, appropriate tests should address the nonlinear regime. In a first case, we show analytically that the weakly nonlinear modulational dynamics of quasi-parallel propagating Alfven waves is well captured. As a second test we consider the parametric decay instability of parallel Alfven waves and show that numerical simulations of the dispersive Landau fluid model lead to results that closely match the outcome of hybrid simulations. (Author)

Computational Models for Nonlinear Aeroelastic Systems, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Clear Science Corp. and Duke University propose to develop and demonstrate new and efficient computational methods of modeling nonlinear aeroelastic systems. The...

Study of the critical behavior of the O(N) linear and nonlinear sigma models

International Nuclear Information System (INIS)

Graziani, F.R.

1983-01-01

A study of the large N behavior of both the O(N) linear and nonlinear sigma models is presented. The purpose is to investigate the relationship between the disordered (ordered) phase of the linear and nonlinear sigma models. Utilizing operator product expansions and stability analyses, it is shown that for 2 - (lambda/sub R/(M) is the dimensionless renormalized quartic coupling and lambda* is the IR fixed point) limit of the linear sigma model which yields the nonlinear sigma model. It is also shown that stable large N linear sigma models with lambda 0) and nonlinear models are trivial. This result (i.e., triviality) is well known but only for one and two component models. Interestingly enough, the lambda< d = 4 linear sigma model remains nontrivial and tachyonic free

Economic evaluations in aggressive non-Hodgkin's lymphoma

NARCIS (Netherlands)

M. van Agthoven (Michel)

2004-01-01

textabstractNon-Hodgkin's lymphoma (NHL) has the highest incidence rate of all haematological malignancies in the Western world 1 • In the USA, the number of deaths attributable to NHL currently ranks in the top five of cancer related deaths2 In the Netherlands, haematological malignancies rank 8 in

Linfoma no Hodgkin primario de mama, revisión de la literatura y presentación de un caso Primary non-Hodgkin breast lymphoma, literature review and a case a presentation

Directory of Open Access Journals (Sweden)

Caridad Verdecia Cañizares

2011-06-01

Full Text Available El linfoma no Hodgkin primario de la mama es una entidad poco frecuente en pediatría y representa el 0,4 al 0,5 % de todos los tumores mamarios malignos. Debido a que carecen de características propias, tanto clínicas, citológicas como ecográficas, resulta muy difícil establecer el diagnóstico preoperatorio. Se presenta el caso de un linfoma no Hodgkin primario de la mama en una paciente de 3 años que llegó en estadio avanzado de la enfermedad, y se subraya la importancia del tratamiento en un equipo multidisciplinario.The primary non-Hodgkin breast lymphoma is a not frequent entity in children and account for the 0,4 to 0,5% of the malignant breast tumors. Due to they lack of own clinical, cytological and echography features, it is very difficult to made the preoperative diagnosis. This is the case of a primary non-Hodgkin breast lymphoma in a patient aged 3 with an advanced stage of disease, emphasizing the significance of treatment in a multidisciplinary staff.

Prognostic factors in Hodgkin's disease stage III with special reference to tumour burden

DEFF Research Database (Denmark)

Specht, L; Nissen, N I

1988-01-01

143 patients with Hodgkin's disease stage III (65 PS III, 78 CS III) were treated with radiotherapy alone (33 patients), combination chemotherapy alone (56 patients), or radiotherapy plus combination chemotherapy (54 patients). They were followed till death or from 7 to 191 months. Prognostic fac...... regarding early stage disease to the effect that tumour burden is the single most important prognostic factor in Hodgkin's disease....

Challenging normative orthodoxies in depression: Huxley's Utopia or Dante's Inferno?

Science.gov (United States)

Cutcliffe, John R; Lakeman, Richard

2010-04-01

Although there appears to be a widespread consensus that depression is a ubiquitous human experience, definitions of depression, its prevalence, and how mental health services respond to it have changed significantly over time, particularly during recent decades. Epistemological limitations notwithstanding, it is now estimated that approximately 121 million people experience depression. At the same time, it should be acknowledged that the last two decades have seen the widespread acceptance of depression as a chemical imbalance and a massive corresponding increase in the prescription of antidepressants, most notably of selective serotonin reuptake inhibitors (SSRIs). However, questions have been raised about the effectiveness and iatrogenic side effects of antidepressants; related questions have also been asked about whose interests are served by the marketing and sales of these drugs. Accordingly, this article attempts to problematize the normative orthodoxy concerning depression and creates a "space" in which an alternative can be articulated and enacted. In so doing, the article finds that the search for a world where the automatic response to depression is a pharmacological intervention not only ignores the use of alternative efficacious treatment options but may also inhibit the persons' chance to explore the meaning of their experience and thus prevent people from individual growth and personal development. Interestingly, in worlds analogous to this pharmacologically induced depression-free state, such as utopias like that in Huxley's Brave New World, no "properly conditioned citizen" is depressed or suicidal. Yet, in the same Brave New World, no one is free to suffer, to be different, or crucially, to be independent. Copyright 2010 Elsevier Inc. All rights reserved.

Testing and Inference in Nonlinear Cointegrating Vector Error Correction Models

DEFF Research Database (Denmark)

Kristensen, Dennis; Rahbæk, Anders

In this paper, we consider a general class of vector error correction models which allow for asymmetric and non-linear error correction. We provide asymptotic results for (quasi-)maximum likelihood (QML) based estimators and tests. General hypothesis testing is considered, where testing...... of non-stationary non-linear time series models. Thus the paper provides a full asymptotic theory for estimators as well as standard and non-standard test statistics. The derived asymptotic results prove to be new compared to results found elsewhere in the literature due to the impact of the estimated...... symmetric non-linear error correction considered. A simulation study shows that the fi…nite sample properties of the bootstrapped tests are satisfactory with good size and power properties for reasonable sample sizes....

Testing and Inference in Nonlinear Cointegrating Vector Error Correction Models

DEFF Research Database (Denmark)

Kristensen, Dennis; Rahbek, Anders

In this paper, we consider a general class of vector error correction models which allow for asymmetric and non-linear error correction. We provide asymptotic results for (quasi-)maximum likelihood (QML) based estimators and tests. General hypothesis testing is considered, where testing...... of non-stationary non-linear time series models. Thus the paper provides a full asymptotic theory for estimators as well as standard and non-standard test statistics. The derived asymptotic results prove to be new compared to results found elsewhere in the literature due to the impact of the estimated...... symmetric non-linear error correction are considered. A simulation study shows that the finite sample properties of the bootstrapped tests are satisfactory with good size and power properties for reasonable sample sizes....

Genomic prediction based on data from three layer lines using non-linear regression models.

Science.gov (United States)

Huang, Heyun; Windig, Jack J; Vereijken, Addie; Calus, Mario P L

2014-11-06

Most studies on genomic prediction with reference populations that include multiple lines or breeds have used linear models. Data heterogeneity due to using multiple populations may conflict with model assumptions used in linear regression methods. In an attempt to alleviate potential discrepancies between assumptions of linear models and multi-population data, two types of alternative models were used: (1) a multi-trait genomic best linear unbiased prediction (GBLUP) model that modelled trait by line combinations as separate but correlated traits and (2) non-linear models based on kernel learning. These models were compared to conventional linear models for genomic prediction for two lines of brown layer hens (B1 and B2) and one line of white hens (W1). The three lines each had 1004 to 1023 training and 238 to 240 validation animals. Prediction accuracy was evaluated by estimating the correlation between observed phenotypes and predicted breeding values. When the training dataset included only data from the evaluated line, non-linear models yielded at best a similar accuracy as linear models. In some cases, when adding a distantly related line, the linear models showed a slight decrease in performance, while non-linear models generally showed no change in accuracy. When only information from a closely related line was used for training, linear models and non-linear radial basis function (RBF) kernel models performed similarly. The multi-trait GBLUP model took advantage of the estimated genetic correlations between the lines. Combining linear and non-linear models improved the accuracy of multi-line genomic prediction. Linear models and non-linear RBF models performed very similarly for genomic prediction, despite the expectation that non-linear models could deal better with the heterogeneous multi-population data. This heterogeneity of the data can be overcome by modelling trait by line combinations as separate but correlated traits, which avoids the occasional

Multivariate Normal Tissue Complication Probability Modeling of Heart Valve Dysfunction in Hodgkin Lymphoma Survivors

International Nuclear Information System (INIS)

Cella, Laura; Liuzzi, Raffaele; Conson, Manuel; D’Avino, Vittoria; Salvatore, Marco; Pacelli, Roberto

2013-01-01

Purpose: To establish a multivariate normal tissue complication probability (NTCP) model for radiation-induced asymptomatic heart valvular defects (RVD). Methods and Materials: Fifty-six patients treated with sequential chemoradiation therapy for Hodgkin lymphoma (HL) were retrospectively reviewed for RVD events. Clinical information along with whole heart, cardiac chambers, and lung dose distribution parameters was collected, and the correlations to RVD were analyzed by means of Spearman's rank correlation coefficient (Rs). For the selection of the model order and parameters for NTCP modeling, a multivariate logistic regression method using resampling techniques (bootstrapping) was applied. Model performance was evaluated using the area under the receiver operating characteristic curve (AUC). Results: When we analyzed the whole heart, a 3-variable NTCP model including the maximum dose, whole heart volume, and lung volume was shown to be the optimal predictive model for RVD (Rs = 0.573, P<.001, AUC = 0.83). When we analyzed the cardiac chambers individually, for the left atrium and for the left ventricle, an NTCP model based on 3 variables including the percentage volume exceeding 30 Gy (V30), cardiac chamber volume, and lung volume was selected as the most predictive model (Rs = 0.539, P<.001, AUC = 0.83; and Rs = 0.557, P<.001, AUC = 0.82, respectively). The NTCP values increase as heart maximum dose or cardiac chambers V30 increase. They also increase with larger volumes of the heart or cardiac chambers and decrease when lung volume is larger. Conclusions: We propose logistic NTCP models for RVD considering not only heart irradiation dose but also the combined effects of lung and heart volumes. Our study establishes the statistical evidence of the indirect effect of lung size on radio-induced heart toxicity

Localization of Hodgkin's disease and lymphomas by 67-gallium substraction scanning

Energy Technology Data Exchange (ETDEWEB)

Krolikiewicz, H; Maruyama, Y; Deland, F H; Beihn, R M; Hafner, T; Utley, J F

1977-01-01

/sup 67/Ga-subtraction scan was found to be useful and a promising new method for the pre-treatment evaluation of the patient with Hodgkin's disease or non-Hodgkin's lymphoma. The scan appeared to be most accurate in the neck, chest, and axillary regions. It appears to offer a means of increasing the accuracy of evaluating the abdomen, the para-aortic and pelvic regions. It may be a useful method for the follow-up to detect recurrences. It was an easily performed, safe, non-invasive test, well tolerated and accepted by patients.

NON-HODGKIN'S LYMPHOMAS OF FEMALE REPRODUCTIVE SYSTEM

Directory of Open Access Journals (Sweden)

A. V. Babkina

2008-01-01

Full Text Available Non-Hodgkin's lymphomas are extremely rare among all tumors of female reproductive system. Diagnostic mistakes and inadequate therapeu- tic tactics in these diseases are results of usual absence of alertness of gynecologists. The aims are to analyze reasons of diagnostic mistakes in patients with non-Hodgkin's lymphomas of female reproductive system and to discover definitive clinical and morphological characteristics of female reproductive system lymphoid tumors. During the period between 1989 and 2006, 305 cases of primary extranodal non-Hodgkin's lym- phomas were detected; female reproductive system was affected in 7% of patients (totally 40 patients, which were included in investigated group. In the whole analyzed group of women (n=40, median age 43 yrs, range 17-84 yrs, patients with primary lesion of female reproductive system had median age of 40 yrs and with secondary involvement - 46 yrs. Most of patients were fertile (60%, n=24. Such tumors was localized in breast in 40% of cases (n=16, in ovaries - 20% (n=8, in uterine corpus - 12,5% (n=5, in uterine cervix - 15% (n=6, and in vagina - remaining 12,5% (n=5. Average time from diagnosis to beginning of the treatment was 7,5 months. As a result, the onset of specific therapy was delayed in 65% cases (n=26 and 50% (n=20 underwent unneeded surgery. Diagnostic mistakes lead to inadequate treatment. Extranodal non-Hodgkin’s lymphomas of female reproductive system, both primary and secondary, are rare pathology. Primary lesion is more typical for older women, sec- ondary is mainly affecting younger women (in reproductive period. Chemotherapy response and prognosis are better in primary cases.

Thyroid neoplasia following radiation therapy for Hodgkin's lymphoma

International Nuclear Information System (INIS)

McHenry, C.; Jarosz, H.; Calandra, D.; McCall, A.; Lawrence, A.M.; Paloyan, E.

1987-01-01

The question of thyroid neoplasia following high-dose radiation treatment to the neck and mediastinum for malignant neoplasms such as Hodgkin's lymphoma in children and young adults has been raised recently. Five patients, 19 to 39 years old, were operated on for thyroid neoplasms that developed following cervical and mediastinal radiation therapy for Hodgkin's lymphoma. Three patients had papillary carcinomas and two had follicular adenomas. The latency period between radiation exposure and the diagnosis of thyroid neoplasm ranged from eight to 16 years. This limited series provided strong support for the recommendation that children and young adults who are to receive high-dose radiation therapy to the head, neck, and mediastinum should receive suppressive doses of thyroxine prior to radiation therapy in order to suppress thyrotropin (thyroid-stimulating hormone) and then be maintained on a regimen of suppression permanently

Renal and perirenal non-Hodgkin's lymphoma: CT findings

International Nuclear Information System (INIS)

Lee, Seon Kyu; Kim, Seung Hyup; Lee, Goo; Choi, Byeung In; Han, Man Chung

1992-01-01

CT findings of 19 kidneys in 12 patients with renal and perirenal non-Hodgkin's lymphoma were retrospectively reviewed to determine distinguishing characteristic and specific findings. CT manifestation of the renal and perirenal lymphoma included multiple nodules in five kidneys(26.3%), trans-capsular infiltration in three kidneys(15.8%), trans-sinus infiltration in nine kidneys(47.4%) and diffuse infiltration in two kidneys(10.5%). Perirenal changes were thickening of the renal fascia in ten kidneys(52.6%) and crescent lesion of low attenuation in the subcapsular area in five kidneys(26.3%) Retroperitoneal lymphadenopathy was evident in eleven patient(57.9%). Renal calyceal dilatation without renal pelvic dilatation(selective calycelal dilatation) was noted in three kidneys. Familiarity with these CT findings of renal and perirenal lymphoma may be helpful in the diagnosis and management of patient with non-Hodgkin's lymphoma

Computational Models for Nonlinear Aeroelastic Systems, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — Clear Science Corp. and Duke University propose to develop and demonstrate a new and efficient computational method of modeling nonlinear aeroelastic systems. The...

Note on off-shell relations in nonlinear sigma model

International Nuclear Information System (INIS)

Chen, Gang; Du, Yi-Jian; Li, Shuyi; Liu, Hanqing

2015-01-01

In this note, we investigate relations between tree-level off-shell currents in nonlinear sigma model. Under Cayley parametrization, all odd-point currents vanish. We propose and prove a generalized U(1) identity for even-point currents. The off-shell U(1) identity given in http://dx.doi.org/10.1007/JHEP01(2014)061 is a special case of the generalized identity studied in this note. The on-shell limit of this identity is equivalent with the on-shell KK relation. Thus this relation provides the full off-shell correspondence of tree-level KK relation in nonlinear sigma model.

Central nervous system complications in non-Hodgkin-lymphomas and radiotherapy

International Nuclear Information System (INIS)

Liffers, R.

1981-01-01

261 case historys of malignant non-Hodgkin-lymphomas were analysed in the years from 1969 until 1978 in the 'Radiologische Universitaetsklinik Kiel'/West-Germany. 18 Patients got a central nervous complication of Non Hodgkin-Lymphoma earlier or later, a percentage of about 7. There were 7 cases of lymphoblastic lymphoma (LB), a percentage of 10 for this entity. In the group of immunoblastic lymphoma (IB) 6 cases of central nervous infiltration were detected, that is a ratio of 7.7 percent. 4 case histories M. Brill-Symmers (CC/CB) were complicated by central nervous dissemination, a percentage of 5.3. Patients with lymphoblastic lymphoma have the highest risk of central nervous complication. The beginning of central nervous dissemination in the single case histories is very different between the histological groups. Patients with lymphoblastic lymphoma suffered from central nervous complication in an early phase of history, in cases of M. Brill-Symmers central nervous infiltration can occur also in a late phase. The results may determine the discussion about stratifying of radiotherapy. Early radiotherapy including central nervous system may be discussed and investigated in special histological entities of malignant non-Hodgkin-lymphoma. (orig.) [de

Fast and accurate modeling of nonlinear pulse propagation in graded-index multimode fibers.

Science.gov (United States)

Conforti, Matteo; Mas Arabi, Carlos; Mussot, Arnaud; Kudlinski, Alexandre

2017-10-01

We develop a model for the description of nonlinear pulse propagation in multimode optical fibers with a parabolic refractive index profile. It consists of a 1+1D generalized nonlinear Schrödinger equation with a periodic nonlinear coefficient, which can be solved in an extremely fast and efficient way. The model is able to quantitatively reproduce recently observed phenomena like geometric parametric instability and broadband dispersive wave emission. We envisage that our equation will represent a valuable tool for the study of spatiotemporal nonlinear dynamics in the growing field of multimode fiber optics.