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Differential equation

Vatsala Goyal, Wilson Torres, Roshan Rai, Frances Shofer, Daniel Bogen, Phillip Bryant, Laura Prosser, Michelle J Johnson
Infants with developmental delays must be detected early in their development to minimize the progression of motor and neurological impairments. Our objective is to quantify how sensorized toys in a natural play environment can promote infant-toy physical interactions. We created a hanging elephant toy, equipped with an inertial measurement unit (IMU), a pressure transducer, and multiple feedback sensors, to be a hand-grasping toy. We used a 3 DoF robotic model with inputs from the IMU to calculate multiple kinematic metrics and an equation to calculate haptic metrics from the pressure transducer...
July 2017: IEEE ... International Conference on Rehabilitation Robotics: [proceedings]
David R Penas, David Henriques, Patricia González, Ramón Doallo, Julio Saez-Rodriguez, Julio R Banga
BACKGROUND: We consider a general class of global optimization problems dealing with nonlinear dynamic models. Although this class is relevant to many areas of science and engineering, here we are interested in applying this framework to the reverse engineering problem in computational systems biology, which yields very large mixed-integer dynamic optimization (MIDO) problems. In particular, we consider the framework of logic-based ordinary differential equations (ODEs). METHODS: We present saCeSS2, a parallel method for the solution of this class of problems...
2017: PloS One
Guilherme W Wendt, Alice J Bartoli, Adriane Arteche
Objective: To investigate the unique contribution of narcissism and impulsivity, in addition to callous-unemotional (CU) traits, in explaining concurrent prosocial and antisocial behavior. Method: Two hundred and forty-nine schoolchildren (53% female; age 9-12 years) completed the self-report Strengths and Difficulties Questionnaire (SDQ) and the Antisocial Process Screening Device (APSD). Two statistical models were tested, predicting conduct problems (CP) and prosocial behavior (PB)...
July 2017: Revista Brasileira de Psiquiatria
Michael J Moulton, Brian D Hong, Timothy W Secomb
The eventual goal of this study is to develop methods for estimating dynamic stresses in the left ventricle (LV) that could be used on-line in clinical settings, based on routinely available measurements. Toward this goal, a low-order theoretical model is presented, in which LV shape is represented using a small number of parameters, allowing rapid computational simulations of LV dynamics. The LV is represented as a thick-walled prolate spheroid containing helical muscle fibers with nonlinear passive and time-dependent active contractile properties...
August 15, 2017: Cardiovascular Engineering and Technology
A Filipponi, P Giammatteo
We implemented a kinetic Monte Carlo computer simulation of the nucleation process in the framework of the coarse grained scenario of the Classical Nucleation Theory (CNT). The computational approach is efficient for a wide range of temperatures and sample sizes and provides a reliable simulation of the stochastic process. The results for the nucleation rate are in agreement with the CNT predictions based on the stationary solution of the set of differential equations for the continuous variables representing the average population distribution of nuclei size...
December 7, 2016: Journal of Chemical Physics
B D Goddard, A Nold, S Kalliadasis
We study the dynamics of colloidal fluids in both unconfined geometries and when confined by a hard wall. Under minimal assumptions, we derive a dynamical density functional theory (DDFT) which includes hydrodynamic interactions (HI; bath-mediated forces). By using an efficient numerical scheme based on pseudospectral methods for integro-differential equations, we demonstrate its excellent agreement with the full underlying Langevin equations for systems of hard disks in partial confinement. We further use the derived DDFT formalism to elucidate the crucial effects of HI in confined systems...
December 7, 2016: Journal of Chemical Physics
Michael Kuron, Georg Rempfer, Florian Schornbaum, Martin Bauer, Christian Godenschwager, Christian Holm, Joost de Graaf
The motion of ionic solutes and charged particles under the influence of an electric field and the ensuing hydrodynamic flow of the underlying solvent is ubiquitous in aqueous colloidal suspensions. The physics of such systems is described by a coupled set of differential equations, along with boundary conditions, collectively referred to as the electrokinetic equations. Capuani et al. [J. Chem. Phys. 121, 973 (2004)] introduced a lattice-based method for solving this system of equations, which builds upon the lattice Boltzmann algorithm for the simulation of hydrodynamic flow and exploits computational locality...
December 7, 2016: Journal of Chemical Physics
Phonindra Nath Das, Ajay Kumar, Nandadulal Bairagi, Samrat Chatterjee
Calcium homeostasis is a key factor in the regulation of cardiac excitation-contraction coupling. Calcium dynamics in cardiomyocytes is governed by ATP which depends on insulin dependent glucose concentration, via the glucose transporter type 4 (GLUT4) transporter. It would therefore be interesting to see how calcium dynamics changes in a cardiomyocyte under diabetic conditions. We proposed and analysed a four dimensional ordinary differential equation (ODE) model to capture the interdependency of calcium dynamics on glucose uptake and ATP generation...
August 10, 2017: Molecular BioSystems
Frank M Hilker, Marta Paliga, Ezio Venturino
Social predators benefit from cooperation in the form of increased hunting success, but may be at higher risk of disease infection due to living in groups. Here, we use mathematical modeling to investigate the impact of disease transmission on the population dynamics benefits provided by group hunting. We consider a predator-prey model with foraging facilitation that can induce strong Allee effects in the predators. We extend this model by an infectious disease spreading horizontally and vertically in the predator population...
August 9, 2017: Bulletin of Mathematical Biology
Mario J Pinheiro
Classical mechanics, as commonly taught in engineering and science, are confined to the conventional Newtonian theory. But classical mechanics has not really changed in substance since Newton formulation, describing simultaneous rotation and translation of objects with somewhat complicate drawbacks, risking interpretation of forces in non-inertial frames. In this work we introduce a new variational principle for out-of-equilibrium, rotating systems, obtaining a set of two first order differential equations that introduces a thermodynamic-mechanistic time into Newton's dynamical equation, and revealing the same formal symplectic structure shared by classical mechanics, fluid mechanics and thermodynamics...
July 2017: Heliyon
Suhas Kumar, John Paul Strachan, R Stanley Williams
At present, machine learning systems use simplified neuron models that lack the rich nonlinear phenomena observed in biological systems, which display spatio-temporal cooperative dynamics. There is evidence that neurons operate in a regime called the edge of chaos that may be central to complexity, learning efficiency, adaptability and analogue (non-Boolean) computation in brains. Neural networks have exhibited enhanced computational complexity when operated at the edge of chaos, and networks of chaotic elements have been proposed for solving combinatorial or global optimization problems...
August 9, 2017: Nature
Jilie Zhang, Huaguang Zhang, Tao Feng
This paper focuses on the distributed optimal cooperative control for continuous-time nonlinear multiagent systems (MASs) with completely unknown dynamics via adaptive dynamic programming (ADP) technology. By introducing predesigned extra compensators, the augmented neighborhood error systems are derived, which successfully circumvents the system knowledge requirement for ADP. It is revealed that the optimal consensus protocols actually work as the solutions of the MAS differential game. Policy iteration algorithm is adopted, and it is theoretically proved that the iterative value function sequence strictly converges to the solution of the coupled Hamilton-Jacobi-Bellman equation...
August 1, 2017: IEEE Transactions on Neural Networks and Learning Systems
Bin Wang, Xiaoyun Dai, Xintao Zhao, Zhenghua Qian
Vibration frequencies and modes for the thickness-shear vibrations of infinite partially-electroded circular AT-cut quartz plates are obtained by solving the two-dimensional (2D) scalar differential equation derived by Tiersten and Smythe. The Mathieu and modified Mathieu equations are derived from the governing equation using the coordinate transform and the collocation method is used to deal with the boundary conditions. Solutions of the resonant frequencies and trapped modes are validated by those results obtained from COMSOL software...
August 7, 2017: Sensors
Zulkarnain, Lal Miyan, Afaq Ahmad, Md Fazle Alam, Hina Younus
The charge transfer (CT) interaction of 2-aminopyrimidine (AP) with chloranilic acid (CLA) as π-acceptor was investigated spectrophotometrically in acetonitrile at different temperatures in the range of 25-50°C. The 1:1 stoichiometry of the synthesized CT complex was detected using straight line method. Benesi-Hildebrand equation was used to determine the association constant (KCT), molar extinction coefficient (ε) and other physical parameters. Various thermodynamics parameters such as enthalpy (ΔH), entropy (ΔS) and free energy (ΔG) were determined using UV-Visible spectrophotometry in acetonitrile at different temperatures...
July 4, 2017: Journal of Photochemistry and Photobiology. B, Biology
Patrick Muchmore, Edward B Rappaport, Sandrah P Eckel
The fractional concentration of nitric oxide in exhaled breath (feNO) is a biomarker of airway inflammation with applications in clinical asthma management and environmental epidemiology. feNO concentration depends on the expiratory flow rate. Standard feNO is assessed at 50 mL/sec, but "extended NO analysis" uses feNO measured at multiple different flow rates to estimate parameters quantifying proximal and distal sources of NO in the lower respiratory tract. Most approaches to modeling multiple flow feNO assume the concentration of NO throughout the airway has achieved a "steady-state...
August 2017: Physiological Reports
Ram P Sigdel, Madhur Anand, Chris T Bauch
Human and environmental systems are often treated as existing in isolation from one another, whereas in fact they are often two parts of a single, coupled human-environment system. Developing theoretical models of coupled human-environment systems is a continuing area of research, although relatively few of these models are based on differential equations. Here we develop a simple differential equation coupled human-environment system model of forest growth dynamics and conservationist opinion dynamics in a human population...
July 31, 2017: Journal of Theoretical Biology
Iman Eshraghi, Seyed K Jalali, Nicola Maria Pugno
Imperfection sensitivity of large amplitude vibration of curved single-walled carbon nanotubes (SWCNTs) is considered in this study. The SWCNT is modeled as a Timoshenko nano-beam and its curved shape is included as an initial geometric imperfection term in the displacement field. Geometric nonlinearities of von Kármán type and nonlocal elasticity theory of Eringen are employed to derive governing equations of motion. Spatial discretization of governing equations and associated boundary conditions is performed using differential quadrature (DQ) method and the corresponding nonlinear eigenvalue problem is iteratively solved...
September 21, 2016: Materials
Francesco Tornabene, Nicholas Fantuzzi, Michele Bacciocchi
A mathematical scheme is proposed here to model a damaged mechanical configuration for laminated and sandwich structures. In particular, two kinds of functions defined in the reference domain of plates and shells are introduced to weaken their mechanical properties in terms of engineering constants: a two-dimensional Gaussian function and an ellipse shaped function. By varying the geometric parameters of these distributions, several damaged configurations are analyzed and investigated through a set of parametric studies...
July 17, 2017: Materials
Michael Schindler
BACKGROUND: The classification of effects caused by mixtures of agents as synergistic, antagonistic or additive depends critically on the reference model of 'null interaction'. Two main approaches are currently in use, the Additive Dose (ADM) or concentration addition (CA) and the Multiplicative Survival (MSM) or independent action (IA) models. We compare several response surface models to a newly developed Hill response surface, obtained by solving a logistic partial differential equation (PDE)...
August 2, 2017: Theoretical Biology & Medical Modelling
Ryan M Evans, David A Edwards
Optical biosensors are often used to measure kinetic rate constants associated with chemical reactions. Such instruments operate in the surface-volume configuration, in which ligand molecules are convected through a fluid-filled volume over a surface to which receptors are confined. Currently, scientists are using optical biosensors to measure the kinetic rate constants associated with DNA translesion synthesis-a process critical to DNA damage repair. Biosensor experiments to study this process involve multiple interacting components on the sensor surface...
August 1, 2017: Bulletin of Mathematical Biology
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