WorldWideScience

Sample records for rigid body behavior

  1. Dynamic Behavior of Wind Turbine by a Mixed Flexible-Rigid Multi-Body Model

    Science.gov (United States)

    Wang, Jianhong; Qin, Datong; Ding, Yi

    A mixed flexible-rigid multi-body model is presented to study the dynamic behavior of a horizontal axis wind turbine. The special attention is given to flexible body: flexible rotor is modeled by a newly developed blade finite element, support bearing elasticities, variations in the number of teeth in contact as well as contact tooth's elasticities are mainly flexible components in the power train. The couple conditions between different subsystems are established by constraint equations. The wind turbine model is generated by coupling models of rotor, power train and generator with constraint equations together. Based on this model, an eigenproblem analysis is carried out to show the mode shape of rotor and power train at a few natural frequencies. The dynamic responses and contact forces among gears under constant wind speed and fixed pitch angle are analyzed.

  2. Dynamical Behavior of a Rigid Body with One Fixed Point (Gyroscope. Basic Concepts and Results. Open Problems: a Review

    Directory of Open Access Journals (Sweden)

    Svetoslav Ganchev Nikolov

    2015-07-01

    Full Text Available The study of the dynamic behavior of a rigid body with one fixed point (gyroscope has a long history. A number of famous mathematicians and mechanical engineers have devoted enormous time and effort to clarify the role of dynamic effects on its movement (behavior – stable, periodic, quasi-periodic or chaotic. The main objectives of this review are: 1 to outline the characteristic features of the theory of dynamical systems and 2 to reveal the specific properties of the motion of a rigid body with one fixed point (gyroscope.This article consists of six sections. The first section addresses the main concepts of the theory of dynamical systems. Section two presents the main theoretical results (obtained so far concerning the dynamic behavior of a solid with one fixed point (gyroscope. Section three examines the problem of gyroscopic stabilization. Section four deals with the non-linear (chaotic dynamics of the gyroscope. Section five is a brief analysis of the gyroscope applications in engineering. The final section provides conclusions and generalizations on why the theory of dynamical systems should be used in the study of the movement of gyroscopic systems.

  3. Rigid body dynamics of mechanisms

    CERN Document Server

    Hahn, Hubert

    2003-01-01

    The second volume of Rigid Body Dynamics of Mechanisms covers applications via a systematic method for deriving model equations of planar and spatial mechanisms. The necessary theoretical foundations have been laid in the first volume that introduces the theoretical mechanical aspects of mechatronic systems. Here the focus is on the application of the modeling methodology to various examples of rigid-body mechanisms, simple planar ones as well as more challenging spatial problems. A rich variety of joint models, active constraints, plus active and passive force elements is treated. The book is intended for self-study by working engineers and students concerned with the control of mechanical systems, i.e. robotics, mechatronics, vehicles, and machine tools. The examples included are a likely source from which to choose models for university lectures.

  4. Rigid multibody system dynamics with uncertain rigid bodies

    Energy Technology Data Exchange (ETDEWEB)

    Batou, A., E-mail: anas.batou@univ-paris-est.fr; Soize, C., E-mail: christian.soize@univ-paris-est.fr [Universite Paris-Est, Laboratoire Modelisation et Simulation Multi Echelle, MSME UMR 8208 CNRS (France)

    2012-03-15

    This paper is devoted to the construction of a probabilistic model of uncertain rigid bodies for multibody system dynamics. We first construct a stochastic model of an uncertain rigid body by replacing the mass, the center of mass, and the tensor of inertia by random variables. The prior probability distributions of the stochastic model are constructed using the maximum entropy principle under the constraints defined by the available information. The generators of independent realizations corresponding to the prior probability distribution of these random quantities are further developed. Then several uncertain rigid bodies can be linked to each other in order to calculate the random response of a multibody dynamical system. An application is proposed to illustrate the theoretical development.

  5. Elasticity of Relativistic Rigid Bodies?

    Science.gov (United States)

    Smarandache, Florentin

    2013-10-01

    In the classical Twin Paradox, according to the Special Theory of Relativity, when the traveling twin blasts off from the Earth to a relative velocity v =√{/3 } 2 c with respect to the Earth, his measuring stick and other physical objects in the direction of relative motion shrink to half their lengths. How is that possible in the real physical world to have let's say a rigid rocket shrinking to half and then later elongated back to normal as an elastic material when it stops? What is the explanation for the traveler's measuring stick and other physical objects, in effect, return to the same length to their original length in the Stay-At-Home, but there is no record of their having shrunk? If it's a rigid (not elastic) object, how can it shrink and then elongate back to normal? It might get broken in such situation.

  6. Quantum mechanics of a generalised rigid body

    International Nuclear Information System (INIS)

    Gripaios, Ben; Sutherland, Dave

    2016-01-01

    We consider the quantum version of Arnold’s generalisation of a rigid body in classical mechanics. Thus, we quantise the motion on an arbitrary Lie group manifold of a particle whose classical trajectories correspond to the geodesics of any one-sided-invariant metric. We show how the derivation of the spectrum of energy eigenstates can be simplified by making use of automorphisms of the Lie algebra and (for groups of type I) by methods of harmonic analysis. We show how the method can be extended to cosets, generalising the linear rigid rotor. As examples, we consider all connected and simply connected Lie groups up to dimension 3. This includes the universal cover of the archetypical rigid body, along with a number of new exactly solvable models. We also discuss a possible application to the topical problem of quantising a perfect fluid. (paper)

  7. Geometric integrators for stochastic rigid body dynamics

    KAUST Repository

    Tretyakov, Mikhail

    2016-01-05

    Geometric integrators play an important role in simulating dynamical systems on long time intervals with high accuracy. We will illustrate geometric integration ideas within the stochastic context, mostly on examples of stochastic thermostats for rigid body dynamics. The talk will be mainly based on joint recent work with Rusland Davidchak and Tom Ouldridge.

  8. Geometric integrators for stochastic rigid body dynamics

    KAUST Repository

    Tretyakov, Mikhail

    2016-01-01

    Geometric integrators play an important role in simulating dynamical systems on long time intervals with high accuracy. We will illustrate geometric integration ideas within the stochastic context, mostly on examples of stochastic thermostats for rigid body dynamics. The talk will be mainly based on joint recent work with Rusland Davidchak and Tom Ouldridge.

  9. The two-body problem of a pseudo-rigid body and a rigid sphere

    DEFF Research Database (Denmark)

    Kristiansen, Kristian Uldall; Vereshchagin, M.; Gózdziewski, K.

    2012-01-01

    n this paper we consider the two-body problem of a spherical pseudo-rigid body and a rigid sphere. Due to the rotational and "re-labelling" symmetries, the system is shown to possess conservation of angular momentum and circulation. We follow a reduction procedure similar to that undertaken...... in the study of the two-body problem of a rigid body and a sphere so that the computed reduced non-canonical Hamiltonian takes a similar form. We then consider relative equilibria and show that the notions of locally central and planar equilibria coincide. Finally, we show that Riemann's theorem on pseudo......-rigid bodies has an extension to this system for planar relative equilibria....

  10. A parametric study of the behavior of the angular momentum vector during spin rate changes of rigid body spacecraft

    Science.gov (United States)

    Longuski, J. M.

    1982-01-01

    During a spin-up or spin-down maneuver of a spinning spacecraft, it is usual to have not only a constant body-fixed torque about the desired spin axis, but also small undesired constant torques about the transverse axes. This causes the orientation of the angular momentum vector to change in inertial space. Since an analytic solution is available for the angular momentum vector as a function of time, this behavior can be studied for large variations of the dynamic parameters, such as the initial spin rate, the inertial properties and the torques. As an example, the spin-up and spin-down maneuvers of the Galileo spacecraft was studied and as a result, very simple heuristic solutions were discovered which provide very good approximations to the parametric behavior of the angular momentum vector orientation.

  11. Almost Poisson integration of rigid body systems

    International Nuclear Information System (INIS)

    Austin, M.A.; Krishnaprasad, P.S.; Li-Sheng Wang

    1993-01-01

    In this paper we discuss the numerical integration of Lie-Poisson systems using the mid-point rule. Since such systems result from the reduction of hamiltonian systems with symmetry by lie group actions, we also present examples of reconstruction rules for the full dynamics. A primary motivation is to preserve in the integration process, various conserved quantities of the original dynamics. A main result of this paper is an O(h 3 ) error estimate for the Lie-Poisson structure, where h is the integration step-size. We note that Lie-Poisson systems appear naturally in many areas of physical science and engineering, including theoretical mechanics of fluids and plasmas, satellite dynamics, and polarization dynamics. In the present paper we consider a series of progressively complicated examples related to rigid body systems. We also consider a dissipative example associated to a Lie-Poisson system. The behavior of the mid-point rule and an associated reconstruction rule is numerically explored. 24 refs., 9 figs

  12. The theory of pseudo-rigid bodies

    CERN Document Server

    Cohen, Harley

    1988-01-01

    This monograph concerns the development, analysis, and application of the theory of pseudo-rigid bodies. It collects together our work on that subject over the last five years. While some results have appeared else­ where, much of the work is new. Our objective in writing this mono­ graph has been to present a new theory of the deformation of bodies, one that has not only a firm theoretical basis, but also the simplicity to serve as an effective tool in practical problems. Consequently, the main body of the treatise is a multifaceted development of the theory, from foundations to explicit solutions to linearizations to methods of approximation. The fact that this variety of aspects, each examined in considerable detail, can be collected together in a single, unified treat­ ment gives this theory an elegance that we feel sets it apart from many others. While our goal has always been to give a complete treatment of the theory as it now stands, the work here is not meant to be definitive. Theories are not ent...

  13. Dual Quaternion Variational Integrator for Rigid Body Dynamic Simulation

    OpenAIRE

    Xu, Jiafeng; Halse, Karl Henning

    2016-01-01

    In rigid body dynamic simulations, often the algorithm is required to deal with general situations where both reference point and inertia matrix are arbitrarily de- fined. We introduce a novel Lie group variational integrator using dual quaternion for simulating rigid body dynamics in all six degrees of freedom. Dual quaternion is used to represent rigid body kinematics and one-step Lie group method is used to derive dynamic equations. The combination of these two becomes the first Lie group ...

  14. Rigid Body Sampling and Individual Time Stepping for Rigid-Fluid Coupling of Fluid Simulation

    Directory of Open Access Journals (Sweden)

    Xiaokun Wang

    2017-01-01

    Full Text Available In this paper, we propose an efficient and simple rigid-fluid coupling scheme with scientific programming algorithms for particle-based fluid simulation and three-dimensional visualization. Our approach samples the surface of rigid bodies with boundary particles that interact with fluids. It contains two procedures, that is, surface sampling and sampling relaxation, which insures uniform distribution of particles with less iterations. Furthermore, we present a rigid-fluid coupling scheme integrating individual time stepping to rigid-fluid coupling, which gains an obvious speedup compared to previous method. The experimental results demonstrate the effectiveness of our approach.

  15. Rigid body motion in stereo 3D simulation

    International Nuclear Information System (INIS)

    Zabunov, Svetoslav

    2010-01-01

    This paper addresses the difficulties experienced by first-grade students studying rigid body motion at Sofia University. Most quantities describing the rigid body are in relations that the students find hard to visualize and understand. They also lose the notion of cause-result relations between vector quantities, such as the relation between torque and angular momentum. Consequently, the understanding of physical laws and conservation principles in free rigid body motion is hampered. This paper presents the capabilities of a 3D simulation, which aims to clarify these questions to the students, who are taught mechanics in the general physics course. The rigid body motion simulations may be observed at http://ialms.net/sim/, and are intended to complement traditional learning practices, not replace them, as the author shares the opinion that no simulation may fully resemble reality.

  16. Stabilization of Rigid Body Dynamics by Internal and External Torques

    National Research Council Canada - National Science Library

    Bloch, A. M; Krishnaprasad, P. S; Marsden, J. E; Sanchez de Alvarez, G

    1990-01-01

    ...] with quadratic feedback torques for internal rotors. We show that with such torques, the equations for the rigid body with momentum wheels are Hamiltonian with respect to a Lie-Poisson bracket structure. Further...

  17. Anti-synchronization of the rigid body exhibiting chaotic dynamics ...

    African Journals Online (AJOL)

    Based on a method derived from nonlinear control theory, we present a ... In this framework, the active control technique is modified and employed to design control ... state space of the two rigid bodies was verified by numerical simulations.

  18. A concise introduction to mechanics of rigid bodies multidisciplinary engineering

    CERN Document Server

    Huang, L

    2017-01-01

    This updated second edition broadens the explanation of rotational kinematics and dynamics — the most important aspect of rigid body motion in three-dimensional space and a topic of much greater complexity than linear motion. It expands treatment of vector and matrix, and includes quaternion operations to describe and analyze rigid body motion which are found in robot control, trajectory planning, 3D vision system calibration, and hand-eye coordination of robots in assembly work, etc. It features updated treatments of concepts in all chapters and case studies. The textbook retains its comprehensiveness in coverage and compactness in size, which make it easily accessible to the readers from multidisciplinary areas who want to grasp the key concepts of rigid body mechanics which are usually scattered in multiple volumes of traditional textbooks. Theoretical concepts are explained through examples taken from across engineering disciplines and links to applications and more advanced courses (e.g. industrial rob...

  19. Knowledge-In-Action: An Example with Rigid Body Motion

    Science.gov (United States)

    Da Costa, Sayonara Salvador Cabral; Moreira, Marco Antonio

    2005-01-01

    This paper reports the analysis of the resolution of a paper-and-pencil problem, by eight undergraduate students majoring in engineering (six) and physics (two) at the Pontifcia Universidade Catlica do Rio Grande do Sul, in Porto Alegre, Brazil. The problem concerns kinetics of a rigid body, and the analysis was done in the light of Johnson-Lairds…

  20. A method for measuring the inertia properties of rigid bodies

    Science.gov (United States)

    Gobbi, M.; Mastinu, G.; Previati, G.

    2011-01-01

    A method for the measurement of the inertia properties of rigid bodies is presented. Given a rigid body and its mass, the method allows to measure (identify) the centre of gravity location and the inertia tensor during a single test. The proposed technique is based on the analysis of the free motion of a multi-cable pendulum to which the body under consideration is connected. The motion of the pendulum and the forces acting on the system are recorded and the inertia properties are identified by means of a proper mathematical procedure based on a least square estimation. After the body is positioned on the test rig, the full identification procedure takes less than 10 min. The natural frequencies of the pendulum and the accelerations involved are quite low, making this method suitable for many practical applications. In this paper, the proposed method is described and two test rigs are presented: the first is developed for bodies up to 3500 kg and the second for bodies up to 400 kg. A validation of the measurement method is performed with satisfactory results. The test rig holds a third part quality certificate according to an ISO 9001 standard and could be scaled up to measure the inertia properties of huge bodies, such as trucks, airplanes or even ships.

  1. Nonlinear dynamics mathematical models for rigid bodies with a liquid

    CERN Document Server

    Lukovsky, Ivan A

    2015-01-01

    This book is devoted to analytically approximate methods in the nonlinear dynamics of a rigid body with cavities partly filled by liquid. It combines several methods and compares the results with experimental data. It is useful for experienced and early-stage readers interested in analytical approaches to fluid-structure interaction problems, the fundamental mathematical background and modeling the dynamics of such complex mechanical systems.

  2. Steady fall of a rigid body in viscous fluid

    Czech Academy of Sciences Publication Activity Database

    Nečasová, Šárka

    2005-01-01

    Roč. 63, Sp. Is. (2005), s. 2113-2119 ISSN 0362-546X. [Invited Talks from the Fourth World Congress of Nonlinear Analysts (WCNA 2004). Orlando , 30.7.2004-7.8.2004] R&D Projects: GA ČR(CZ) GA201/02/0684 Institutional research plan: CEZ:AV0Z1019905 Keywords : steady fall * rigid body * viscous fluid Subject RIV: BA - General Mathematics Impact factor: 0.519, year: 2005

  3. Rigid Body Energy Minimization on Manifolds for Molecular Docking.

    Science.gov (United States)

    Mirzaei, Hanieh; Beglov, Dmitri; Paschalidis, Ioannis Ch; Vajda, Sandor; Vakili, Pirooz; Kozakov, Dima

    2012-11-13

    Virtually all docking methods include some local continuous minimization of an energy/scoring function in order to remove steric clashes and obtain more reliable energy values. In this paper, we describe an efficient rigid-body optimization algorithm that, compared to the most widely used algorithms, converges approximately an order of magnitude faster to conformations with equal or slightly lower energy. The space of rigid body transformations is a nonlinear manifold, namely, a space which locally resembles a Euclidean space. We use a canonical parametrization of the manifold, called the exponential parametrization, to map the Euclidean tangent space of the manifold onto the manifold itself. Thus, we locally transform the rigid body optimization to an optimization over a Euclidean space where basic optimization algorithms are applicable. Compared to commonly used methods, this formulation substantially reduces the dimension of the search space. As a result, it requires far fewer costly function and gradient evaluations and leads to a more efficient algorithm. We have selected the LBFGS quasi-Newton method for local optimization since it uses only gradient information to obtain second order information about the energy function and avoids the far more costly direct Hessian evaluations. Two applications, one in protein-protein docking, and the other in protein-small molecular interactions, as part of macromolecular docking protocols are presented. The code is available to the community under open source license, and with minimal effort can be incorporated into any molecular modeling package.

  4. Bang-Bang Practical Stabilization of Rigid Bodies

    Science.gov (United States)

    Serpelloni, Edoardo

    In this thesis, we study the problem of designing a practical stabilizer for a rigid body equipped with a set of actuators generating only constant thrust. Our motivation stems from the fact that modern space missions are required to accurately control the position and orientation of spacecraft actuated by constant-thrust jet-thrusters. To comply with the performance limitations of modern thrusters, we design a feedback controller that does not induce high-frequency switching of the actuators. The proposed controller is hybrid and it asymptotically stabilizes an arbitrarily small compact neighborhood of the target position and orientation of the rigid body. The controller is characterized by a hierarchical structure comprising of two control layers. At the low level of the hierarchy, an attitude controller stabilizes the target orientation of the rigid body. At the high level, after the attitude controller has steered the rigid body sufficiently close to its desired orientation, a position controller stabilizes the desired position. The size of the neighborhood being stabilized by the controller can be adjusted via a proper selection of the controller parameters. This allows us to stabilize the rigid body to virtually any degree of accuracy. It is shown that the controller, even in the presence of measurement noise, does not induce high-frequency switching of the actuators. The key component in the design of the controller is a hybrid stabilizer for the origin of double-integrators affected by bounded external perturbations. Specifically, both the position and the attitude stabilizers consist of multiple copies of such a double-integrator controller. The proposed controller is applied to two realistic spacecraft control problems. First, we apply the position controller to the problem of stabilizing the relative position between two spacecraft flying in formation in the vicinity of the L2 libration point of the Sun-Earth system as a part of a large space telescope

  5. Euler-Poincare Reduction of Externall Forced Rigid Body Motion

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Kulczycki, P.

    2004-01-01

    If a mechanical system experiences symmetry, the Lagrangian becomes invariant under a certain group action. This property leads to substantial simplification of the description of movement. The standpoint in this article is a mechanical system affected by an external force of a control action....... Assuming that the system possesses symmetry and the configuration manifold corresponds to a Lie group, the Euler-Poincaré reduction breaks up the motion into separate equations of dynamics and kinematics. This becomes of particular interest for modelling, estimation and control of mechanical systems......-known Euler-Poincaré reduction to a rigid body motion with forcing....

  6. Euler-Poincare Reduction of a Rigid Body Motion

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Kulczycki, P.

    2005-01-01

    |If a mechanical system experiences symmetry, the Lagrangian becomes invariant under a certain group action. This property leads to substantial simplification of the description of movement. The standpoint in this article is a mechanical system afected by an external force of a control action....... Assuming that the system possesses symmetry and the configuration manifold corresponds to a Lie group, the Euler-Poincare reduction breaks up the motion into separate equations of dynamics and kinematics. This becomes of particular interest for modeling, estimation and control of mechanical systems......-known Euler-Poincare reduction to a rigid body motion with forcing....

  7. Euler-Poincaré Reduction of a Rigid Body Motion

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Kulczycki, P.

    2004-01-01

    If a mechanical system experiences symmetry, the Lagrangian becomes invariant under a certain group action. This property leads to substantial simplification of the description of movement. The standpoint in this article is a mechanical system affected by an external force of a control action....... Assuming that the system possesses symmetry and the configuration manifold corresponds to a Lie group, the Euler-Poincaré reduction breaks up the motion into separate equations of dynamics and kinematics. This becomes of particular interest for modelling, estimation and control of mechanical systems......-known Euler-Poincaré reduction to a rigid body motion with forcing....

  8. Collisions of Constrained Rigid Body Systems with Friction

    Directory of Open Access Journals (Sweden)

    Haijun Shen

    1998-01-01

    Full Text Available A new approach is developed for the general collision problem of two rigid body systems with constraints (e.g., articulated systems, such as massy linkages in which the relative tangential velocity at the point of contact and the associated friction force can change direction during the collision. This is beyond the framework of conventional methods, which can give significant and very obvious errors for this problem, and both extends and consolidates recent work. A new parameterization and theory characterize if, when and how the relative tangential velocity changes direction during contact. Elastic and dissipative phenomena and different values for static and kinetic friction coefficients are included. The method is based on the explicitly physical analysis of events at the point of contact. Using this method, Example 1 resolves (and corrects a paradox (in the literature of the collision of a double pendulum with the ground. The method fundamentally subsumes other recent models and the collision of rigid bodies; it yields the same results as conventional methods when they would apply (Example 2. The new method reformulates and extends recent approaches in a completely physical context.

  9. Rigid body formulation in a finite element context with contact interaction

    Science.gov (United States)

    Refachinho de Campos, Paulo R.; Gay Neto, Alfredo

    2018-03-01

    The present work proposes a formulation to employ rigid bodies together with flexible bodies in the context of a nonlinear finite element solver, with contact interactions. Inertial contributions due to distribution of mass of a rigid body are fully developed, considering a general pole position associated with a single node, representing a rigid body element. Additionally, a mechanical constraint is proposed to connect a rigid region composed by several nodes, which is useful for linking rigid/flexible bodies in a finite element environment. Rodrigues rotation parameters are used to describe finite rotations, by an updated Lagrangian description. In addition, the contact formulation entitled master-surface to master-surface is employed in conjunction with the rigid body element and flexible bodies, aiming to consider their interaction in a rigid-flexible multibody environment. New surface parameterizations are presented to establish contact pairs, permitting pointwise interaction in a frictional scenario. Numerical examples are provided to show robustness and applicability of the methods.

  10. Matrix methods applied to engineering rigid body mechanics

    Science.gov (United States)

    Crouch, T.

    The purpose of this book is to present the solution of a range of rigorous body mechanics problems using a matrix formulation of vector algebra. Essential theory concerning kinematics and dynamics is formulated in terms of matrix algebra. The solution of kinematics and dynamics problems is discussed, taking into account the velocity and acceleration of a point moving in a circular path, the velocity and acceleration determination for a linkage, the angular velocity and angular acceleration of a roller in a taper-roller thrust race, Euler's theroem on the motion of rigid bodies, an automotive differential, a rotating epicyclic, the motion of a high speed rotor mounted in gimbals, and the vibration of a spinning projectile. Attention is given to the activity of a force, the work done by a conservative force, the work and potential in a conservative system, the equilibrium of a mechanism, bearing forces due to rotor misalignment, and the frequency of vibrations of a constrained rod.

  11. Dynamics of parallel robots from rigid bodies to flexible elements

    CERN Document Server

    Briot, Sébastien

    2015-01-01

    This book starts with a short recapitulation on basic concepts, common to any types of robots (serial, tree structure, parallel, etc.), that are also necessary for computation of the dynamic models of parallel robots. Then, as dynamics requires the use of geometry and kinematics, the general equations of geometric and kinematic models of parallel robots are given. After, it is explained that parallel robot dynamic models can be obtained by decomposing the real robot into two virtual systems: a tree-structure robot (equivalent to the robot legs for which all joints would be actuated) plus a free body corresponding to the platform. Thus, the dynamics of rigid tree-structure robots is analyzed and algorithms to obtain their dynamic models in the most compact form are given. The dynamic model of the real rigid parallel robot is obtained by closing the loops through the use of the Lagrange multipliers. The problem of the dynamic model degeneracy near singularities is treated and optimal trajectory planning for cro...

  12. Unifying Rigid and Soft Bodies Representation: The Sulfur Physics Engine

    Directory of Open Access Journals (Sweden)

    Dario Maggiorini

    2014-01-01

    Full Text Available Video games are (also real-time interactive graphic simulations: hence, providing a convincing physics simulation for each specific game environment is of paramount importance in the process of achieving a satisfying player experience. While the existing game engines appropriately address many aspects of physics simulation, some others are still in need of improvements. In particular, several specific physics properties of bodies not usually involved in the main game mechanics (e.g., properties useful to represent systems composed by soft bodies, are often poorly rendered by general-purpose engines. This issue may limit game designers when imagining innovative and compelling video games and game mechanics. For this reason, we dug into the problem of appropriately representing soft bodies. Subsequently, we have extended the approach developed for soft bodies to rigid ones, proposing and developing a unified approach in a game engine: Sulfur. To test the engine, we have also designed and developed “Escape from Quaoar,” a prototypal video game whose main game mechanic exploits an elastic rope, and a level editor for the game.

  13. Leonhard Euler and the mechanics of rigid bodies

    Science.gov (United States)

    Marquina, J. E.; Marquina, M. L.; Marquina, V.; Hernández-Gómez, J. J.

    2017-01-01

    In this work we present the original ideas and the construction of the rigid bodies theory realised by Leonhard Euler between 1738 and 1775. The number of treatises written by Euler on this subject is enormous, including the most notorious Scientia Navalis (1749), Decouverte d’un noveau principe de mecanique (1752), Du mouvement de rotation des corps solides autour d’un axe variable (1765), Theoria motus corporum solidorum seu rigidorum (1765) and Nova methodus motu corporum rigidorum determinandi (1776), in which he developed the ideas of the instantaneous rotation axis, the so-called Euler equations and angles, the components of what is now known as the inertia tensor, the principal axes of inertia, and, finally, the generalisation of the translation and rotation movement equations for any system. Euler, the man who ‘put most of mechanics into its modern form’ (Truesdell 1968 Essays in the History of Mechanics (Berlin: Springer) p 106).

  14. Dynamics of Rigid Bodies and Flexible Beam Structures

    DEFF Research Database (Denmark)

    Nielsen, Martin Bjerre

    of rigid bodies and flexible beam structures with emphasis on the rotational motion. The first part deals with motion in a rotating frame of reference. A novel approach where the equations of motion are formulated in a hybrid state-space in terms of local displacements and global velocities is presented...... quaternion parameters or nine convected base vector components. In both cases, the equations of motion are obtained via Hamilton’s equations by including the kinematic constraints associated with the redundant rotation description by means of Lagrange multipliers. A special feature of the formulation...... of the global components of the position vectors and associated convected base vectors for the element nodes. The kinematics is expressed in a homogeneous quadratic form and the constitutive stiffness is derived from complementary energy of a set of equilibrium modes, each representing a state of constant...

  15. Damageable contact between an elastic body and a rigid foundation

    Science.gov (United States)

    Campo, M.; Fernández, J. R.; Silva, A.

    2009-02-01

    In this work, the contact problem between an elastic body and a rigid obstacle is studied, including the development of material damage which results from internal compression or tension. The variational problem is formulated as a first-kind variational inequality for the displacements coupled with a parabolic partial differential equation for the damage field. The existence of a unique local weak solution is stated. Then, a fully discrete scheme is introduced using the finite element method to approximate the spatial variable and an Euler scheme to discretize the time derivatives. Error estimates are derived on the approximate solutions, from which the linear convergence of the algorithm is deduced under suitable regularity conditions. Finally, three two-dimensional numerical simulations are performed to demonstrate the accuracy and the behaviour of the scheme.

  16. Dynamical analysis of an orbiting three-rigid-body system

    Energy Technology Data Exchange (ETDEWEB)

    Pagnozzi, Daniele, E-mail: daniele.pagnozzi@strath.ac.uk, E-mail: james.biggs@strath.ac.uk; Biggs, James D., E-mail: daniele.pagnozzi@strath.ac.uk, E-mail: james.biggs@strath.ac.uk [Department of Mechanical and Aerospace Engineering, University of Strathclyde, Glasgow, Scotland (United Kingdom)

    2014-12-10

    The development of multi-joint-spacecraft mission concepts calls for a deeper understanding of their nonlinear dynamics to inform and enhance system design. This paper presents a study of a three-finite-shape rigid-body system under the action of an ideal central gravitational field. The aim of this paper is to gain an insight into the natural dynamics of this system. The Hamiltonian dynamics is derived and used to identify relative attitude equilibria of the system with respect to the orbital reference frame. Then a numerical investigation of the behaviour far from the equilibria is provided using tools from modern dynamical systems theory such as energy methods, phase portraits and Poincarè maps. Results reveal a complex structure of the dynamics as well as the existence of connections between some of the equilibria. Stable equilibrium configurations appear to be surrounded by very narrow regions of regular and quasi-regular motions. Trajectories evolve on chaotic motions in the rest of the domain.

  17. Dynamic Multi-Rigid-Body Systems with Concurrent Distributed Contacts: Theory and Examples

    International Nuclear Information System (INIS)

    TRINKLE, JEFFREY C.; TZITZOURIS, J.A.; PANG, J.S.

    2001-01-01

    Consider a system of rigid bodies with multiple concurrent contacts. The multi-rigid-body contact problem is to predict the accelerations of the bodies and the normal friction loads acting at the contacts. This paper presents theoretical results for the multi-rigid-body contact problem under the assumptions that one or more contacts occur over locally planar, finite regions and that friction forces are consistent with the maximum work inequality. Existence and uniqueness results are presented for this problem under mild assumptions on the system inputs. In addition, the performance of two different time-stepping methods for integrating the dynamics are compared on two simple multi-body systems

  18. Simulating Dynamics of the System of Articulated Rigid Bodies with Joint Friction

    Directory of Open Access Journals (Sweden)

    M. V. Michaylyuk

    2016-01-01

    Full Text Available The subject of the work is to simulate dynamics of the system of articulated rigid bodies in the virtual environment complexes. The work aim is to develop algorithms and methods to simulate the multi-body system dynamics with joint friction to ensure all calculations in real time in line with visual realistic behavior of objects in a scene.The paper describes the multibody system based on a maximal set of coordinates, and to simulate the joint friction is used a Coulomb's law of dry friction. Joints are described using the holonomic constraints and their derivatives that specify the constraints on velocities of joined bodies. Based on The Coulomb’s law a correlation for the friction impulse values has been derived as an inequality. If the friction impulse performs a constraint that is a lack of relative motion of two joint-joined bodies, there is a static friction in the joint. Otherwise, there is a dynamic friction in the joint. Using a semi-implicit Euler method allows us to describe dynamics of articulated rigid bodies with joint friction as a system of linear algebraic equations and inequalities for the unknown velocities and impulse values.To solve the obtained system of equations and inequalities is used an iterative method of sequential impulses, which sequentially processes constraints for each joint with impulse calculation and its application to the joined bodies rather than considers the entire system. To improve the method convergence, at each iteration the calculated impulses are accumulated for their further using as an initial approximation at the next step of simulation.The proposed algorithms and methods have been implemented in the training complex dynamics subsystem, developed in SRISA RAS. Evaluation of these methods and algorithms has demonstrated their full adequacy to requirements for virtual environment systems and training complexes.

  19. Effort Flow Analysis: A Methodology for Directed Product Evolution Using Rigid Body and Compliant Mechanisms

    National Research Council Canada - National Science Library

    Greer, James

    2002-01-01

    This dissertation presents a systematic design methodology for directed product evolution that uses both rigid body and compliant mechanisms to facilitate component combination in the domain of mechanical products...

  20. Almost-global tracking for a rigid body with internal rotors

    OpenAIRE

    Nayak, Aradhana; Banavar, Ravi N.

    2017-01-01

    Almost-global orientation trajectory tracking for a rigid body with external actuation has been well studied in the literature, and in the geometric setting as well. The tracking control law relies on the fact that a rigid body is a simple mechanical system (SMS) on the $3-$dimensional group of special orthogonal matrices. However, the problem of designing feedback control laws for tracking using internal actuation mechanisms, like rotors or control moment gyros, has received lesser attention...

  1. Rigid body displacement fields of an in-plane-deformable curved beam based on conventional strain definition

    International Nuclear Information System (INIS)

    Moon, Won Joo; Min, Oak Key; Kim, Yong Woo

    1998-01-01

    To improve the convergence and the accuracy of a finite element, the finite element has to describe not only displacement and stress distributions in a static analysis but also rigid body displacements. In this paper, we consider the in-plane-deformable curved beam element to understand the descriptive capability of rigid body displacements of a finite element. We derive the rigid body displacement fields of a single finite element under various essential boundary conditions when the nodal displacements are caused by the rigid body displacement. We also examine the rigid body displacement fields of a quadratic curved beam element by employing the reduced minimization theory

  2. Evolution of motions of a rigid body about its center of mass

    CERN Document Server

    Chernousko, Felix L; Leshchenko, Dmytro D

    2017-01-01

    The book presents a unified and well-developed approach to the dynamics of angular motions of rigid bodies subjected to perturbation torques of different physical nature. It contains both the basic foundations of the rigid body dynamics and of the asymptotic method of averaging. The rigorous approach based on the averaging procedure is applicable to bodies with arbitrary ellopsoids of inertia. Action of various perturbation torques, both external (gravitational, aerodynamical, solar pressure) and internal (due to viscous fluid in tanks, elastic and visco-elastic properties of a body) is considered in detail. The book can be used by researchers, engineers and students working in attitude dynamics of spacecraft.

  3. In silico single-molecule manipulation of DNA with rigid body dynamics.

    Directory of Open Access Journals (Sweden)

    Pascal Carrivain

    2014-02-01

    Full Text Available We develop a new powerful method to reproduce in silico single-molecule manipulation experiments. We demonstrate that flexible polymers such as DNA can be simulated using rigid body dynamics thanks to an original implementation of Langevin dynamics in an open source library called Open Dynamics Engine. We moreover implement a global thermostat which accelerates the simulation sampling by two orders of magnitude. We reproduce force-extension as well as rotation-extension curves of reference experimental studies. Finally, we extend the model to simulations where the control parameter is no longer the torsional strain but instead the torque, and predict the expected behavior for this case which is particularly challenging theoretically and experimentally.

  4. Body fixed frame, rigid gauge rotations and large N random fields in QCD

    International Nuclear Information System (INIS)

    Levit, S.

    1995-01-01

    The ''body fixed frame'' with respect to local gauge transformations is introduced. Rigid gauge ''rotations'' in QCD and their Schroedinger equation are studied for static and dynamic quarks. Possible choices of the rigid gauge field configuration corresponding to a non-vanishing static colormagnetic field in the ''body fixed'' frame are discussed. A gauge invariant variational equation is derived in this frame. For large number N of colors the rigid gauge field configuration is regarded as random with maximally random probability distribution under constraints on macroscopic-like quantities. For the uniform magnetic field the joint probability distribution of the field components is determined by maximizing the appropriate entropy under the area law constraint for the Wilson loop. In the quark sector the gauge invariance requires the rigid gauge field configuration to appear not only as a background but also as inducing an instantaneous quark-quark interaction. Both are random in the large N limit. (orig.)

  5. Simulation Methods in the Contact with Impact of Rigid Bodies

    Directory of Open Access Journals (Sweden)

    Cristina Basarabă-Opritescu

    2007-10-01

    Full Text Available The analysis of impacts of elastic bodies is topical and it has many applications, practical and theoretical, too. The elastic character of collision is put in evidence, especially by the velocities of some parts of a particular body, named “ring”. In the presented paper, the situation of elastic collisions is put in evidence by the simulation with the help of the program ANSYS and it refers to the particular case of the ring, with the mechanical characteristics, given in the paper

  6. Student understanding of the application of Newton's second law to rotating rigid bodies

    Science.gov (United States)

    Close, Hunter G.; Gomez, Luanna S.; Heron, Paula R. L.

    2013-06-01

    We report on an investigation of student understanding of rigid body dynamics in which we asked students in introductory calculus-based physics to compare the translational motions of identical rigid bodies subject to forces that differed only in the point of contact at which they were applied. There was a widespread tendency to claim that forces that cause rotational motion have a diminished effect on translational motion. A series of related problems was developed to examine whether similar errors would be made in other contexts, and interviews were conducted to probe student thinking in greater depth. In this paper, we describe the results of our investigation and also describe a series of different interventions that culminated in the development of a tutorial that improves student ability to apply Newton's second law to rotating rigid bodies.

  7. Estimating the orientation of a rigid body moving in space using inertial sensors

    Energy Technology Data Exchange (ETDEWEB)

    He, Peng, E-mail: peng.he.1@ulaval.ca; Cardou, Philippe, E-mail: pcardou@gmc.ulaval.ca [Université Laval, Robotics Laboratory, Department of Mechanical Engineering (Canada); Desbiens, André, E-mail: andre.desbiens@gel.ulaval.ca [Université Laval, Department of Electrical and Computer Engineering (Canada); Gagnon, Eric, E-mail: Eric.Gagnon@drdc-rddc.gc.ca [RDDC Valcartier (Canada)

    2015-09-15

    This paper presents a novel method of estimating the orientation of a rigid body moving in space from inertial sensors, by discerning the gravitational and inertial components of the accelerations. In this method, both a rigid-body kinematics model and a stochastic model of the human-hand motion are formulated and combined in a nonlinear state-space system. The state equation represents the rigid body kinematics and stochastic model, and the output equation represents the inertial sensor measurements. It is necessary to mention that, since the output equation is a nonlinear function of the state, the extended Kalman filter (EKF) is applied. The absolute value of the error from the proposed method is shown to be less than 5 deg in simulation and in experiments. It is apparently stable, unlike the time-integration of gyroscope measurements, which is subjected to drift, and remains accurate under large accelerations, unlike the tilt-sensor method.

  8. Estimating the orientation of a rigid body moving in space using inertial sensors

    International Nuclear Information System (INIS)

    He, Peng; Cardou, Philippe; Desbiens, André; Gagnon, Eric

    2015-01-01

    This paper presents a novel method of estimating the orientation of a rigid body moving in space from inertial sensors, by discerning the gravitational and inertial components of the accelerations. In this method, both a rigid-body kinematics model and a stochastic model of the human-hand motion are formulated and combined in a nonlinear state-space system. The state equation represents the rigid body kinematics and stochastic model, and the output equation represents the inertial sensor measurements. It is necessary to mention that, since the output equation is a nonlinear function of the state, the extended Kalman filter (EKF) is applied. The absolute value of the error from the proposed method is shown to be less than 5 deg in simulation and in experiments. It is apparently stable, unlike the time-integration of gyroscope measurements, which is subjected to drift, and remains accurate under large accelerations, unlike the tilt-sensor method

  9. Computing the Free Energy along a Reaction Coordinate Using Rigid Body Dynamics.

    Science.gov (United States)

    Tao, Peng; Sodt, Alexander J; Shao, Yihan; König, Gerhard; Brooks, Bernard R

    2014-10-14

    The calculations of potential of mean force along complex chemical reactions or rare events pathways are of great interest because of their importance for many areas in chemistry, molecular biology, and material science. The major difficulty for free energy calculations comes from the great computational cost for adequate sampling of the system in high-energy regions, especially close to the reaction transition state. Here, we present a method, called FEG-RBD, in which the free energy gradients were obtained from rigid body dynamics simulations. Then the free energy gradients were integrated along a reference reaction pathway to calculate free energy profiles. In a given system, the reaction coordinates defining a subset of atoms (e.g., a solute, or the quantum mechanics (QM) region of a quantum mechanics/molecular mechanics simulation) are selected to form a rigid body during the simulation. The first-order derivatives (gradients) of the free energy with respect to the reaction coordinates are obtained through the integration of constraint forces within the rigid body. Each structure along the reference reaction path is separately subjected to such a rigid body simulation. The individual free energy gradients are integrated along the reference pathway to obtain the free energy profile. Test cases provided demonstrate both the strengths and weaknesses of the FEG-RBD method. The most significant benefit of this method comes from the fast convergence rate of the free energy gradient using rigid-body constraints instead of restraints. A correction to the free energy due to approximate relaxation of the rigid-body constraint is estimated and discussed. A comparison with umbrella sampling using a simple test case revealed the improved sampling efficiency of FEG-RBD by a factor of 4 on average. The enhanced efficiency makes this method effective for calculating the free energy of complex chemical reactions when the reaction coordinate can be unambiguously defined by a

  10. Topology Optimization of a Vibrating System of Rigid and Flexible Bodies for Maximizing Repeated Eigenfrequencies

    International Nuclear Information System (INIS)

    Ahn, Byungseong; Kim, Suh In; Kim, Yoon Young

    2016-01-01

    When a system consisting of rigid and flexible bodies is optimized to improve its dynamic characteristics, its eigenfrequencies are typically maximized. While topology optimization formulations dealing with simultaneous design of a system of rigid and flexible bodies are available, studies on eigenvalue maximization of the system are rare. In particular, no work has solved for the case when the target frequency becomes one of the repeated eigenfrequencies. The problem involving repeated eigenfrequencies is solved in this study, and a topology optimization formulation and sensitivity analysis are presented. Further, several numerical case studies are considered to demonstrate the validity of the proposed formulation

  11. A comparative study of velocity increment generation between the rigid body and flexible models of MMET

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Norilmi Amilia, E-mail: aenorilmi@usm.my [School of Aerospace Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Pulau Pinang (Malaysia)

    2016-02-01

    The motorized momentum exchange tether (MMET) is capable of generating useful velocity increments through spin–orbit coupling. This study presents a comparative study of the velocity increments between the rigid body and flexible models of MMET. The equations of motions of both models in the time domain are transformed into a function of true anomaly. The equations of motion are integrated, and the responses in terms of the velocity increment of the rigid body and flexible models are compared and analysed. Results show that the initial conditions, eccentricity, and flexibility of the tether have significant effects on the velocity increments of the tether.

  12. Control of fluid-containing rotating rigid bodies

    CERN Document Server

    Gurchenkov, Anatoly A

    2013-01-01

    This book is devoted to the study of the dynamics of rotating bodies with cavities containing liquid. Two basic classes of motions are analyzed: rotation and libration. Cases of complete and partial filling of cavities with ideal liquid and complete filling with viscous liquid are treated. The volume presents a method for obtaining relations between angular velocities perpendicular to main rotation and external force momentums, which are treated as control. The developed models and methods of solving dynamical problems as well as numerical methods for solving problems of optimal control can be

  13. Motion control of rigid bodies in SE(3)

    Science.gov (United States)

    Roza, Ashton

    This thesis investigates the control of motion for a general class of vehicles that rotate and translate in three-space, and are propelled by a thrust vector which has fixed direction in body frame. The thesis addresses the problems of path following and position control. For path following, a feedback linearization controller is presented that makes the vehicle follow an arbitrary closed curve while simultaneously allowing the designer to specify the velocity profile of the vehicle on the path and its heading. For position control, a two-stage approach is presented that decouples position control from attitude control, allowing for a modular design and yielding almost global asymptotic stability of any desired hovering equilibrium. The effectiveness of the proposed method is verified both in simulation and experimentally by means of a hardware-in-the-loop setup emulating a co-axial helicopter.

  14. A conservative quaternion-based time integration algorithm for rigid body rotations with implicit constraints

    DEFF Research Database (Denmark)

    Nielsen, Martin Bjerre; Krenk, Steen

    2012-01-01

    A conservative time integration algorithm for rigid body rotations is presented in a purely algebraic form in terms of the four quaternions components and the four conjugate momentum variables via Hamilton’s equations. The introduction of an extended mass matrix leads to a symmetric set of eight...

  15. Rigid Body Time Integration by Convected Base Vectors with Implicit Constraints

    DEFF Research Database (Denmark)

    Krenk, Steen; Nielsen, Martin Bjerre

    2013-01-01

    of the kinetic energy used in the present formulation is deliberately chosen to correspond to a rigid body rotation, and the orthonormality constraints are introduced via the equivalent Green strain components of the base vectors. The particular form of the extended inertia tensor used here implies a set...

  16. A rigid-body least-squares program with angular and translation scan facilities

    CERN Document Server

    Kutschabsky, L

    1981-01-01

    The described computer program, written in CERN Fortran, is designed to enlarge the convergence radius of the rigid-body least-squares method by allowing a stepwise change of the angular and/or translational parameters within a chosen range. (6 refs).

  17. Diffusion-accomodated rigid-body translations along grain boundaries in nanostructured materials

    International Nuclear Information System (INIS)

    Bachurin, D.V.; Nazarov, A.A.; Shenderova, O.A.; Brenner, D.W.

    2003-01-01

    A model for the structural relaxation of grain boundaries (GBs) in nanostructured materials (NSMs) by diffusion-accommodated rigid body translations along GBs is proposed. The model is based on the results of recent computer simulations that have demonstrated that the GBs in NSMs retain a high-energy structure with random translational states due to severe geometrical constraints applied from neighboring grains (J. Appl. Phys. 78 (1995) 847; Scripta Metall. Mater. 33 (1995) 1245). The shear stresses within a GB caused by non-optimized rigid-body translations (RBTs) can be accommodated by diffusive flow of atoms along a GB. This mechanism is particularly important for low-angle and vicinal GBs, the energy of which noticeably depends on the rigid body translations. At moderate and high temperatures the model yields relaxation times that are very short and therefore GBs in NSMs can attain an equilibrium structure with optimized rigid body translations. In contrast, at room temperature the model predicts that in some metals non-equilibrium structures can be preserved for a long time, which may result in the observation of grain boundary structures different from those in coarse grained polycrystals

  18. On the linear problem arising from motion of a fluid around a moving rigid body

    Czech Academy of Sciences Publication Activity Database

    Nečasová, Šárka; Wolf, J.

    2015-01-01

    Roč. 140, č. 2 (2015), s. 241-259 ISSN 0862-7959 R&D Projects: GA ČR(CZ) GAP201/11/1304 Institutional support: RVO:67985840 Keywords : incompressible fluid * rotating rigid body * strong solution Subject RIV: BA - General Mathematics http://hdl.handle.net/10338.dmlcz/144329

  19. Reconstructing rotations and rigid body motions from exact point correspondences through reflections

    NARCIS (Netherlands)

    Fontijne, D.; Dorst, L.; Dorst, L.; Lasenby, J.

    2011-01-01

    We describe a new algorithm to reconstruct a rigid body motion from point correspondences. The algorithm works by constructing a series of reflections which align the points with their correspondences one by one. This is naturally and efficiently implemented in the conformal model of geometric

  20. Rigid Body Motion Calculated From Spatial Co-ordinates of Markers ...

    African Journals Online (AJOL)

    In this paper, we present a unified method for calculating spatial coordinates of markers for a rigid body motion such as in bones. Kinematical analysis of bone movement in cadaveric specimens or living objects had been developed. Here, we show how spatial co-ordinates of markers in or on bone can be calculated from ...

  1. Flutter Instability of a Fluid-Conveying Fluid-Immersed Pipe Affixed to a Rigid Body

    Science.gov (United States)

    2011-01-01

    rigid body, denoted by y in Fig. 4, is small. This is in addition to the Euler– Bernoulli beam assumption that the slope of the tail is small everywhere...here. These include the efficiency with which the prime mover can generate fluid momentum , pipe losses, and external drag acting on both the hull and the

  2. Lorentz Contraction, Bell's Spaceships and Rigid Body Motion in Special Relativity

    Science.gov (United States)

    Franklin, Jerrold

    2010-01-01

    The meaning of Lorentz contraction in special relativity and its connection with Bell's spaceships parable is discussed. The motion of Bell's spaceships is then compared with the accelerated motion of a rigid body. We have tried to write this in a simple form that could be used to correct students' misconceptions due to conflicting earlier…

  3. Lorentz contraction, Bell's spaceships and rigid body motion in special relativity

    International Nuclear Information System (INIS)

    Franklin, Jerrold

    2010-01-01

    The meaning of Lorentz contraction in special relativity and its connection with Bell's spaceships parable is discussed. The motion of Bell's spaceships is then compared with the accelerated motion of a rigid body. We have tried to write this in a simple form that could be used to correct students' misconceptions due to conflicting earlier treatments.

  4. Numerical algorithm for rigid body position estimation using the quaternion approach

    Science.gov (United States)

    Zigic, Miodrag; Grahovac, Nenad

    2017-11-01

    This paper deals with rigid body attitude estimation on the basis of the data obtained from an inertial measurement unit mounted on the body. The aim of this work is to present the numerical algorithm, which can be easily applied to the wide class of problems concerning rigid body positioning, arising in aerospace and marine engineering, or in increasingly popular robotic systems and unmanned aerial vehicles. Following the considerations of kinematics of rigid bodies, the relations between accelerations of different points of the body are given. A rotation matrix is formed using the quaternion approach to avoid singularities. We present numerical procedures for determination of the absolute accelerations of the center of mass and of an arbitrary point of the body expressed in the inertial reference frame, as well as its attitude. An application of the algorithm to the example of a heavy symmetrical gyroscope is presented, where input data for the numerical procedure are obtained from the solution of differential equations of motion, instead of using sensor measurements.

  5. Viscoelastic materials with anisotropic rigid particles: stress-deformation behavior

    NARCIS (Netherlands)

    Sagis, L.M.C.; Linden, van der E.

    2001-01-01

    In this paper we have derived constitutive equations for the stress tensor of a viscoelastic material with anisotropic rigid particles. We have assumed that the material has fading memory. The expressions are valid for slow and small deformations from equilibrium, and for systems that are nearly

  6. EDF fragment relocation model based on the displacement of rigid bodies

    International Nuclear Information System (INIS)

    Callu, C.; Baron, D.; Ruck, J.M.

    1997-01-01

    In order to release the restricting conditions imposed to the reactor operations with regards to PCMI (Pellet-Cladding Mechanical Interaction), the simulation of a fuel rod thermomechanical behavior has to be improved. The computer programming has to cope with the more and more sophisticated mathematical modellings induced by the complexity and the interdependence of the phenomena. Therefore EDF is developing a new code - CYRANO3 - since 1990 putting emphasis on its evolution capacities. Concerning more precisely the PCMI simulation, the pellet fragmentation and the fragments relocation is one of the major aspect one must account for. Thanks to recent analytical experiments, EDF developed a new modelling based on the displacement of rigid bodies and on the calculation of the interaction efforts between the fragments. This paper presents the basis of the model, its introduction within the CYRANO3 code and its calibration on a specific analytical experiment. The modelling is then tested against PWR fuel rods deformations from the EDF data base. The results are presented and discussed. (author)

  7. Modeling of a light elastic beam by a system of rigid bodies

    Directory of Open Access Journals (Sweden)

    Šalinić Slaviša

    2004-01-01

    Full Text Available This paper has shown that a light elastic beam, in the case of small elastic deformations, can be modeled by a kinematic chain without branching composed of rigid bodies which are connected by passive revolute or prismatic joints with corresponding springs in them. Elastic properties of the beam are modeled by the springs introduced. The potential energy of the elastic beam is expressed as a function of components of the vector of elastic displacement and the vector of elastic rotation calculated for the elastic centre of the beam, which results in the diagonal stiffness matrix of the beam. As the potential energy of the introduced system of bodies with springs is expressed in the function of relative joint displacements, the diagonal stiffness matrix is obtained. In addition, these two stiffness matrices are equal. The modeling process has been demonstrated on the example of an elastic beam rotating about a fixed vertical axis, with a rigid body whose mass is considerably larger than the beam mass fixed to its free end. Differential equations of motion have been formed for this mechanical system. The modeling technique described here aims at expanding of usage of well developed methods of dynamics of systems of rigid bodies to the analysis of systems with elastic bodies. .

  8. Modelling of transport and collisions between rigid bodies to simulate the jam formation in urban flows

    Directory of Open Access Journals (Sweden)

    S Hadji

    2008-09-01

    Full Text Available This study deals with the simulation of transport and interaction betweenbodies considered as a rectangular shape particles, in urban flow. We usedan hydrodynamic two-dimensional finite elements model coupled to theparticles model based on Maxey-Riley equations, and taking into accountof contact between bodies. The finite element discretization is based onthe velocity field richer than pressure field, and the particles displacementsare computed by using a rigid body motion method. A collision strategy isalso developed to handle cases in which bodies touch.

  9. On the monoaxial stabilization of a rigid body under vanishing restoring torque

    Science.gov (United States)

    Aleksandrov, A. Yu.; Aleksandrova, E. B.; Tikhonov, A. A.

    2018-05-01

    The problem of monoaxial stabilization of a rigid body is studied. It is assumed that a linear time-invariant dissipative torque and a time-varying restoring torque vanishing as time increases act on the body. Both the case of linear restoring torque and that of essentially nonlinear one are considered. With the aid of the decomposition method, conditions are obtained under which we can guarantee the asymptotic stability of an equilibrium position of the body despite the vanishing of the restoring torque. A numerical simulation is provided to demonstrate the effectiveness of our theoretical results.

  10. Efficient time-symmetric simulation of torqued rigid bodies using Jacobi elliptic functions

    International Nuclear Information System (INIS)

    Celledoni, E; Saefstroem, N

    2006-01-01

    If the three moments of inertia are distinct, the solution to the Euler equations for the free rigid body is given in terms of Jacobi elliptic functions. Using the arithmetic-geometric mean algorithm (Abramowitz and Stegun 1992 Handbook of Mathematical Functions with Formulas, Graphs, and Mathematical Tables (New York: Dover)), these functions can be calculated efficiently and accurately. Compared to standard numerical ODE and Lie-Poisson solvers, the overall approach yields a faster and more accurate numerical solution to the Euler equations. This approach is designed for mass asymmetric rigid bodies. In the case of symmetric bodies, the exact solution is available in terms of trigonometric functions, see Dullweber et al (1997 J. Chem. Phys. 107 5840-51), Reich (1996 Fields Inst. Commun. 10 181-91) and Benettin et al (2001 SIAM J. Sci. Comp. 23 1189-203) for details. In this paper, we consider the case of asymmetric rigid bodies subject to external forces. We consider a strategy similar to the symplectic splitting method proposed in Reich (1996 Fields Inst. Commun. 10 181-91) and Dullweber et al (1997 J. Chem. Phys. 107 5840-51). The method proposed here is time-symmetric. We decompose the vector field of our problem into a free rigid body (FRB) problem and another completely integrable vector field. The FRB problem consists of the Euler equations and a differential equation for the 3 x 3 orientation matrix. The Euler equations are integrated exactly while the matrix equation is approximated using a truncated Magnus series. In our experiments, we observe that the overall numerical solution benefits greatly from the very accurate solution of the Euler equations. We apply the method to the heavy top and the simulation of artificial satellite attitude dynamics

  11. New integrable problems in a rigid body dynamics with cubic integral in velocities

    Science.gov (United States)

    Elmandouh, A. A.

    2018-03-01

    We introduce a new family of the 2D integrable mechanical system possessing an additional integral of the third degree in velocities. This system contains 20 arbitrary parameters. We also clarify that the majority of the previous systems with a cubic integral can be reconstructed from it as a special version for certain values of those parameters. The applications of this system are extended to include the problem of motion of a particle and rigid body about its fixed point. We announce new integrable problems describing the motion of a particle in the plane, pseudosphere, and surfaces of variable curvature. We also present a new integrable problem in a rigid body dynamics and this problem generalizes some of the previous results for Sokolov-Tsiganov, Yehia, Stretensky, and Goriachev.

  12. Contact point generation for convex polytopes in interactive rigid body dynamics

    DEFF Research Database (Denmark)

    Silcowitz-Hansen, Morten; Abel, Sarah Maria Niebe; Erleben, Kenny

    When computing contact forces in rigid body dynamics systems, most state-of-the-art solutions use iterative methods such as the projected Gauss–Seidel (PGS) method. Methods such as the PGS method are preferred for their robustness. However, the time-critical nature of interactive applications...... combined with the linear convergence rates of such methods, will often result in visual artifacts in the final simulation. With this paper, we address an issue which is of major impact on the animation quality, when using methods such as the PGS method. The issue is robust generation of contact points...... for convex polytopes. A novel contact point generation method is presented, which is based on growth distances and Gauss maps. We demonstrate improvements when using our method in the context of interactive rigid body simulation...

  13. High-order conservative discretizations for some cases of the rigid body motion

    International Nuclear Information System (INIS)

    Kozlov, Roman

    2008-01-01

    Modified vector fields can be used to construct high-order structure-preserving numerical integrators for ordinary differential equations. In the present Letter we consider high-order integrators based on the implicit midpoint rule, which conserve quadratic first integrals. It is shown that these integrators are particularly suitable for the rigid body motion with an additional quadratic first integral. In this case high-order integrators preserve all four first integrals of motion. The approach is illustrated on the Lagrange top (a rotationally symmetric rigid body with a fixed point on the symmetry axis). The equations of motion are considered in the space fixed frame because in this frame Lagrange top admits a neat description. The Lagrange top motion includes the spherical pendulum and the planar pendulum, which swings in a vertical plane, as particular cases

  14. Topological classification of the Goryachev integrable case in rigid body dynamics

    International Nuclear Information System (INIS)

    Nikolaenko, S S

    2016-01-01

    A topological analysis of the Goryachev integrable case in rigid body dynamics is made on the basis of the Fomenko-Zieschang theory. The invariants (marked molecules) which are obtained give a complete description, from the standpoint of Liouville classification, of the systems of Goryachev type on various level sets of the energy. It turns out that on appropriate energy levels the Goryachev case is Liouville equivalent to many classical integrable systems and, in particular, the Joukowski, Clebsch, Sokolov and Kovalevskaya-Yehia cases in rigid body dynamics, as well as to some integrable billiards in plane domains bounded by confocal quadrics -- in other words, the foliations given by the closures of generic solutions of these systems have the same structure. Bibliography: 15 titles

  15. Research on Rigid Body Motion Tracing in Space based on NX MCD

    Science.gov (United States)

    Wang, Junjie; Dai, Chunxiang; Shi, Karen; Qin, Rongkang

    2018-03-01

    In the use of MCD (Mechatronics Concept Designer) which is a module belong to SIEMENS Ltd industrial design software UG (Unigraphics NX), user can define rigid body and kinematic joint to make objects move according to the existing plan in simulation. At this stage, user may have the desire to see the path of some points in the moving object intuitively. In response to this requirement, this paper will compute the pose through the transformation matrix which can be available from the solver engine, and then fit these sampling points through B-spline curve. Meanwhile, combined with the actual constraints of rigid bodies, the traditional equal interval sampling strategy was optimized. The result shown that this method could satisfy the demand and make up for the deficiency in traditional sampling method. User can still edit and model on this 3D curve. Expected result has been achieved.

  16. Friction effects on lateral loading behavior of rigid piles

    DEFF Research Database (Denmark)

    Zania, Varvara; Hededal, Ole

    2012-01-01

    taking into account the shear frictional resistance along the pile. For this purpose efficient three dimensional finite element models of different diameter have been developed. The increase of the side friction and of the diameter of the pile is shown to alter the failure pattern and increase...... the lateral capacity of the pile. The obtained p - y curves demonstrate the importance of the aforementioned parameters in the design of rigid piles, as the reduction of friction along the interface reduces not only the ultimate load but also the stiffness of the soil-pile response. Read More: http...

  17. The motion of the rigid body in viscous fluid including collisions. Global solvability result

    Czech Academy of Sciences Publication Activity Database

    Chemetov, N.; Nečasová, Šárka

    2017-01-01

    Roč. 34, April (2017), s. 416-445 ISSN 1468-1218 R&D Projects: GA ČR GA16-03230S Institutional support: RVO:67985840 Keywords : rigid body * global weak solution * collisions in finite time Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics Impact factor: 1.659, year: 2016 http://www.sciencedirect.com/science/article/pii/S1468121816301146

  18. Estimation of the ground shaking from the response of rigid bodies

    Directory of Open Access Journals (Sweden)

    Filomena de Silva

    2016-12-01

    Full Text Available The paper illustrates and compares simplified approaches to interpret the mechanisms of damage observed on rigid bodies in the cemetery of Amatrice, after the main shock (August 24, 2016, MW=6.0 of the Central Italy earthquake. The final goal of the work is to link the observed movements of the fallen objects to specific characteristics of the ground motion occurred at the specific site.

  19. Rigid-body displacement perpendicular to a {211} twin boundary in Mo

    Czech Academy of Sciences Publication Activity Database

    Gemperlová, Juliana; Vystavěl, Tomáš; Gemperle, Antonín; Pénisson, J. M.

    2001-01-01

    Roč. 31, č. 11 (2001), s. 1767-1778 ISSN 0141-8637 R&D Projects: GA AV ČR IAA1010916; GA ČR GA202/99/1665 Institutional research plan: CEZ:AV0Z1010914 Keywords : sigma=3 Mo bicrystal * rigid-body displacement * alfa- fringe method Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.238, year: 2001

  20. A Compliant Bistable Mechanism Design Incorporating Elastica Buckling Beam Theory and Pseudo-Rigid-Body Model

    DEFF Research Database (Denmark)

    Sönmez, Ümit; Tutum, Cem Celal

    2008-01-01

    In this work, a new compliant bistable mechanism design is introduced. The combined use of pseudo-rigid-body model (PRBM) and the Elastica buckling theory is presented for the first time to analyze the new design. This mechanism consists of the large deflecting straight beams, buckling beams...... and the buckling Elastica solution for an original compliant mechanism kinematic analysis. New compliant mechanism designs are presented to highlight where such combined kinematic analysis is required....

  1. Frontal Tasks and Behavior in Rigid or Tremor-Dominant Parkinson Disease.

    Science.gov (United States)

    Moretti, Rita; Milner, Vera; Caruso, Paola; Gazzin, Silvia; Rumiati, Raffaella

    2017-08-01

    Parkinson disease (PD) is not an unambiguous entity, and there is a general consensus for the statement that an akinetic-rigid dominant type of presentation has a worse prognosis, in the follow-up. The aim of our study was to examine the differences in frontal tasks and behavior, in 2 PD naive groups: the rigid and the tremor-dominant types of presentation, according to motor scores. Our study has showed some important differences in frontal tasks and in behavior, performing more apathy, aggressiveness, and irritability in the rigid type, and more depression and anxiety in the tremor-dominant type. The former group causes the caregiver more distress and has a very rapid disease progression. It can be argued that rigid type PD presentation needs specific dedicated cares and more strong clinical attention.

  2. Motion of a Rigid Body Supported at One Point by a Rotating Arm

    Directory of Open Access Journals (Sweden)

    Jeffrey D. Stoen

    1993-01-01

    Full Text Available This article details a scheme for evaluating the stability of motions of a system consisting of a rigid body connected at one point to a rotating arm. The nonlinear equations of motion for the system are formulated, and a method for finding exact solutions representing motions that resemble a state of rest is presented. The equations are then linearized and roots of the eigensystem are classified and used to construct stability diagrams that facilitate the assessment of effects of varying the body's mass properties and system geometry, changing the position of the attachment joint, and adding energy dissipation in the joint.

  3. On Classical Dynamics of Affinely-Rigid Bodies Subject to the Kirchhoff-Love Constraints

    Directory of Open Access Journals (Sweden)

    Vasyl Kovalchuk

    2010-04-01

    Full Text Available In this article we consider the affinely-rigid body moving in the three-dimensional physical space and subject to the Kirchhoff-Love constraints, i.e., while it deforms homogeneously in the two-dimensional central plane of the body it simultaneously performs one-dimensional oscillations orthogonal to this central plane. For the polar decomposition we obtain the stationary ellipsoids as special solutions of the general, strongly nonlinear equations of motion. It is also shown that these solutions are conceptually different from those obtained earlier for the two-polar (singular value decomposition.

  4. Governing equations of multi-component rigid body-spring discrete element models of reinforced concrete columns

    International Nuclear Information System (INIS)

    Guan, P B; Tingatinga, E A; Longalong, R E; Saguid, J

    2016-01-01

    During the past decades, the complexity of conventional methods to perform seismic performance assessment of buildings led to the development of more effective approaches. The rigid body spring-discrete element method (RBS-DEM) is one of these approaches and has recently been applied to the study of the behavior of reinforced concrete (RC) buildings subjected to strong earthquakes. In this paper, the governing equations of RBS-DEM planar elements subjected to lateral loads and horizontal ground motion are presented and used to replicate the hysteretic behavior of experimental RC columns. The RBS-DEM models of columns are made up of rigid components connected by systems of springs that simulate axial, shear, and bending behavior of an RC section. The parameters of springs were obtained using Response-2000 software and the hysteretic response of the models of select columns from the Pacific Earthquake Engineering Research (PEER) Structural Performance Database were computed numerically. Numerical examples show that one-component models were able to simulate the initial stiffness reasonably, while the displacement capacity of actual columns undergoing large displacements were underestimated. (paper)

  5. Diagnostic-Photographic Determination of Drag/Lift/Torque Coefficients of High Speed Rigid Body in Water Column

    National Research Council Canada - National Science Library

    Chu, Peter C; Fan, Chenwu; Gefken, Paul R

    2008-01-01

    Prediction of rigid body falling through water column with a high speed (such as Mk-84 bomb) needs formulas for drag/lift and torque coefficients, which depend on various physical processes such as supercavitation and bubbles...

  6. Modeling and experimentation with asymmetric rigid bodies: a variation on disks and inclines

    International Nuclear Information System (INIS)

    Raviola, Lisandro A; Zárate, Oscar; Rodríguez, Eduardo E

    2014-01-01

    We study the ascending motion of a disk rolling on an incline when its centre of mass lies outside the disk axis. The problem is suitable as laboratory project for a first course in mechanics at the undergraduate level and goes beyond typical textbook problems about bi-dimensional rigid body motions. We develop a theoretical model for the disk motion based on mechanical energy conservation and compare its predictions with experimental data obtained by digital video recording. Using readily available resources, a very satisfactory agreement is obtained between the model and the experimental observations. These results complement previous ones that have been reported in the literature for similar systems. (paper)

  7. Euler-Poincaré Reduction of Externally Forced Rigid Body Motion

    DEFF Research Database (Denmark)

    Wisniewski, Rafal; Kulczycki, P.

    2004-01-01

    If a mechanical system experiences symmetry, the Lagrangian becomes invariant under a certain group action. This property leads to substantial simplification of the description of movement. The standpoint in this article is a mechanical system affected by an external force of a control action....... Assuming that the system possesses symmetry and the configuration manifold corresponds to a Lie group, the Euler-Poincaré reduction breaks up the motion into separate equations of dynamics and kinematics. This becomes of particular interest for modelling, estimation and control of mechanical systems......-known Euler-Poincaré reduction to a rigid body motion with forcing....

  8. Coupling characteristics of rigid body motion and elastic deformation of a 3-PRR parallel manipulator with flexible links

    International Nuclear Information System (INIS)

    Zhang Xuping; Mills, James K.; Cleghorn, William L.

    2009-01-01

    Modeling of multibody dynamics with flexible links is a challenging task, which not only involves the effect of rigid body motion on elastic deformations, but also includes the influence of elastic deformations on rigid body motion. This paper presents coupling characteristics of rigid body motions and elastic motions of a 3-PRR parallel manipulator with three flexible intermediate links. The intermediate links are modeled as Euler-Bernoulli beams with pinned-pinned boundary conditions based on the assumed mode method (AMM). Using Lagrange multipliers, the fully coupled equations of motions of the flexible parallel manipulator are developed by incorporating the rigid body motions with elastic motions. The mutual dependence of elastic deformations and rigid body motions are investigated from the analysis of the derived equations of motion. Open-loop simulation without joint motion controls and closed-loop simulation with joint motion controls are performed to illustrate the effect of elastic motion on rigid body motions and the coupling effect amongst flexible links. These analyses and results provide valuable insight to the design and control of the parallel manipulator with flexible intermediate links

  9. The general problem of the motion of coupled rigid bodies about a fixed point

    CERN Document Server

    Leimanis, Eugene

    1965-01-01

    In the theory of motion of several coupled rigid bodies about a fixed point one can distinguish three basic ramifications. 1. The first, the so-called classical direction of investigations, is concerned with particular cases of integrability ot the equations of motion of a single rigid body about a fixed point,1 and with their geo­ metrical interpretation. This path of thought was predominant until the beginning of the 20th century and its most illustrious represen­ tatives are L. EULER (1707-1783), J L. LAGRANGE (1736-1813), L. POINSOT (1777-1859), S. V. KOVALEVSKAYA (1850-1891), and others. Chapter I of the present monograph intends to reflect this branch of investigations. For collateral reading on the general questions dealt with in this chapter the reader is referred to the following textbooks and reports: A. DOMOGAROV [1J, F. KLEIN and A. SOMMERFELD [11, 1 , 1 J, A. G. 2 3 GREENHILL [10J, A. GRAY [1J, R. GRAMMEL [4 J, E. J. ROUTH [21' 2 , 1 2 31' 32J, J. B. SCARBOROUGH [1J, and V. V. GOLUBEV [1, 2J.

  10. Association of Rigid-Compulsive Behavior with Functional Constipation in Autism Spectrum Disorder

    Science.gov (United States)

    Marler, Sarah; Ferguson, Bradley J.; Lee, Evon Batey; Peters, Brittany; Williams, Kent C.; McDonnell, Erin; Macklin, Eric A.; Levitt, Pat; Margolis, Kara Gross; Beversdorf, David Q.; Veenstra-VanderWeele, Jeremy

    2017-01-01

    Based upon checklist data from the Autism Speaks Autism Treatment Network, we hypothesized that functional constipation (FC) would be associated with rigid-compulsive behavior in children with autism spectrum disorder (ASD). We used the Questionnaire on Pediatric Gastrointestinal Symptoms-Rome III to assess FC symptoms in 108 children with ASD. As…

  11. Rigid-Compulsive Behaviors Are Associated with Mixed Bowel Symptoms in Autism Spectrum Disorder

    Science.gov (United States)

    Peters, Brittany; Williams, Kent C.; Gorrindo, Phillip; Rosenberg, Daniel; Lee, Evon Batey; Levitt, Pat; Veenstra-VanderWeele, Jeremy

    2014-01-01

    Based on clinical experience, we hypothesized that rigid-compulsive behaviors are associated with severe constipation and co-occurring diarrhea or underwear staining in children with autism spectrum disorder. Using data from the Autism Treatment Network, we evaluated the association between these gastrointestinal symptoms and measures of rigid…

  12. Constrained non-rigid registration for whole body image registration: method and validation

    Science.gov (United States)

    Li, Xia; Yankeelov, Thomas E.; Peterson, Todd E.; Gore, John C.; Dawant, Benoit M.

    2007-03-01

    3D intra- and inter-subject registration of image volumes is important for tasks that include measurements and quantification of temporal/longitudinal changes, atlas-based segmentation, deriving population averages, or voxel and tensor-based morphometry. A number of methods have been proposed to tackle this problem but few of them have focused on the problem of registering whole body image volumes acquired either from humans or small animals. These image volumes typically contain a large number of articulated structures, which makes registration more difficult than the registration of head images, to which the vast majority of registration algorithms have been applied. To solve this problem, we have previously proposed an approach, which initializes an intensity-based non-rigid registration algorithm with a point based registration technique [1, 2]. In this paper, we introduce new constraints into our non-rigid registration algorithm to prevent the bones from being deformed inaccurately. Results we have obtained show that the new constrained algorithm leads to better registration results than the previous one.

  13. Rigidity in Gender-Typed Behaviors in Early Childhood: A Longitudinal Study of Ethnic Minority Children

    Science.gov (United States)

    Ruble, Diane; Tamis-LeMonda, Catherine; Shrout, Patrick E.

    2014-01-01

    A key prediction of cognitive theories of gender development concerns developmental trajectories in the relative strength or rigidity of gender typing. To examine these trajectories in early childhood, 229 children (African American, Mexican, Dominican) were followed annually from age 3 to 5 and gender-stereotypical appearance, dress-up play, toy play, and sex segregation were examined. High gender-typing was found across ethnic group, and most behaviors increased in rigidity, especially from age 3 to 4. In addressing controversy surrounding the stability and structure of gender-typing it was found that from year to year, most behaviors showed moderately stable individual differences. Behaviors were uncorrelated within age, but showed more concordance in change across time, suggesting that aspects of gender-typing are multidimensional but still show coherence. PMID:23432471

  14. Rigidity in gender-typed behaviors in early childhood: a longitudinal study of ethnic minority children.

    Science.gov (United States)

    Halim, May Ling; Ruble, Diane; Tamis-LeMonda, Catherine; Shrout, Patrick E

    2013-01-01

    A key prediction of cognitive theories of gender development concerns developmental trajectories in the relative strength or rigidity of gender typing. To examine these trajectories in early childhood, 229 children (African American, Mexican American, and Dominican American) were followed annually from age 3 to 5 years, and gender-stereotypical appearance, dress-up play, toy play, and sex segregation were examined. High gender-typing was found across ethnic groups, and most behaviors increased in rigidity, especially from age 3 to 4 years. In addressing controversy surrounding the stability and structure of gender-typing it was found that from year to year, most behaviors showed moderately stable individual differences. Behaviors were uncorrelated within age but showed more concordance in change across time, suggesting that aspects of gender-typing are multidimensional, but still show coherence. © 2013 The Authors. Child Development © 2013 Society for Research in Child Development, Inc.

  15. Higher order coupling between rigid-body and elastic motion in flexible mechanisms

    International Nuclear Information System (INIS)

    Esat, I.I.; Ianakiev, A.

    1995-01-01

    The paper presents an investigation of the influence of the higher order coupling terms between the rigid-body and elastic motion into flexible mechanism dynamics. The configuration of the mechanical system is obtained by using the so called hybrid coordinates. The kinematic description of the mechanism was obtained using the D-H 4 x 4 transformation matrices. The elastic deformation of each point of the mechanism is described by the finite element modeling (FEM) type interpolation scheme. The dynamic model of the flexible mechanism consists due to the hybrid coordinates of two groups of differential equations. The first group describes the manipulator transport motion and the second group describes the vibration. In this paper the authors evaluated the contribution of the coupling terms between the two groups of differential equations and selected only those with high contribution

  16. On potential energies and constraints in the dynamics of rigid bodies and particles

    Directory of Open Access Journals (Sweden)

    O'reilly Oliver M.

    2002-01-01

    Full Text Available A new treatment of kinematical constraints and potential energies arising in the dynamics of systems of rigid bodies and particles is presented which is suited to Newtonian and Lagrangian formulations. Its novel feature is the imposing of invariance requirements on the constraint functions and potential energy functions. These requirements are extensively used in continuum mechanics and, in the present context, one finds certain generalizations of Newton's third law of motion and an elucidation of the nature of constraint forces and moments. One motivation for such a treatment can be found by considering approaches where invariance requirements are ignored. In contrast to the treatment presented in this paper, it is shown that this may lead to a difficulty in formulating the equations governing the motion of the system.

  17. Conservative rigid body dynamics by convected base vectors with implicit constraints

    DEFF Research Database (Denmark)

    Krenk, Steen; Nielsen, Martin Bjerre

    2014-01-01

    of differential equations without additional algebraic constraints on the base vectors. A discretized form of the equations of motion is obtained by starting from a finite time increment of the Hamiltonian, and retracing the steps of the continuous formulation in discrete form in terms of increments and mean...... of the base vectors. Orthogonality and unit length of the base vectors are imposed by constraining the equivalent Green strain components, and the kinetic energy is represented corresponding to rigid body motion. The equations of motion are obtained via Hamilton’s equations including the zero...... values over each integration time increment. In this discrete form the Lagrange multipliers are given in terms of a representative value within the integration time interval, and the equations of motion are recast into a conservative mean-value and finite difference format. The Lagrange multipliers...

  18. Dynamics on strata of trigonal Jacobians and some integrable problems of rigid body motion

    International Nuclear Information System (INIS)

    Braden, H W; Enolski, V Z; Fedorov, Yu N

    2013-01-01

    We present an algebraic geometrical and analytical description of the Goryachev case of rigid body motion. It belongs to a family of systems sharing the same properties: although completely integrable, they are not algebraically integrable, their solution is not meromorphic in the complex time and involves dynamics on the strata of the Jacobian varieties of trigonal curves. Although the strata of hyperelliptic Jacobians have already appeared in the literature in the context of some dynamical systems, the Goryachev case is the first example of an integrable system whose solution involves a more general curve. Several new features (and formulae) are encountered in the solution given in terms of sigma-functions of such a curve. (paper)

  19. Conservative integration of rigid body motion by quaternion parameters with implicit constraints

    DEFF Research Database (Denmark)

    Nielsen, Martin Bjerre; Krenk, Steen

    2012-01-01

    An angular momentum and energy‐conserving time integration algorithm for rigid body rotation is formulated in terms of the quaternion parameters and the corresponding four‐component conjugate momentum vector via Hamilton's equations. The introduction of an extended mass matrix leads to a symmetric...... these equations via the set of momentum equations. Initially, the normalization of the quaternion array is introduced via a Lagrange multiplier. However, this Lagrange multiplier can be expressed explicitly in terms of the gradient of the external load potential, and elimination of the Lagrange multiplier from...... the final format leaves only an explicit projection applied to the external load potential gradient. An algorithm is developed by forming a finite increment of the Hamiltonian. This procedure identifies the proper selection of increments and mean values, and leads to an algorithm with conservation...

  20. Rigid-body-spring model numerical analysis of joint performance of engineered cementitious composites and concrete

    Science.gov (United States)

    Khmurovska, Y.; Štemberk, P.; Křístek, V.

    2017-09-01

    This paper presents a numerical investigation of effectiveness of using engineered cementitious composites with polyvinyl alcohol fibers for concrete cover layer repair. A numerical model of a monolithic concaved L-shaped concrete structural detail which is strengthened with an engineered cementitious composite layer with polyvinyl alcohol fibers is created and loaded with bending moment. The numerical analysis employs nonlinear 3-D Rigid-Body-Spring Model. The proposed material model shows reliable results and can be used in further studies. The engineered cementitious composite shows extremely good performance in tension due to the strain-hardening effect. Since durability of the bond can be decreased significantly by its degradation due to the thermal loading, this effect should be also taken into account in the future work, as well as the experimental investigation, which should be performed for validation of the proposed numerical model.

  1. Free Energy Landscapes of Alanine Oligopeptides in Rigid-Body and Hybrid Water Models.

    Science.gov (United States)

    Nayar, Divya; Chakravarty, Charusita

    2015-08-27

    Replica exchange molecular dynamics is used to study the effect of different rigid-body (mTIP3P, TIP4P, SPC/E) and hybrid (H1.56, H3.00) water models on the conformational free energy landscape of the alanine oligopeptides (acAnme and acA5nme), in conjunction with the CHARMM22 force field. The free energy landscape is mapped out as a function of the Ramachandran angles. In addition, various secondary structure metrics, solvation shell properties, and the number of peptide-solvent hydrogen bonds are monitored. Alanine dipeptide is found to have similar free energy landscapes in different solvent models, an insensitivity which may be due to the absence of possibilities for forming i-(i + 4) or i-(i + 3) intrapeptide hydrogen bonds. The pentapeptide, acA5nme, where there are three intrapeptide backbone hydrogen bonds, shows a conformational free energy landscape with a much greater degree of sensitivity to the choice of solvent model, though the three rigid-body water models differ only quantitatively. The pentapeptide prefers nonhelical, non-native PPII and β-sheet populations as the solvent is changed from SPC/E to the less tetrahedral liquid (H1.56) to an LJ-like liquid (H3.00). The pentapeptide conformational order metrics indicate a preference for open, solvent-exposed, non-native structures in hybrid solvent models at all temperatures of study. The possible correlations between the properties of solvent models and secondary structure preferences of alanine oligopeptides are discussed, and the competition between intrapeptide, peptide-solvent, and solvent-solvent hydrogen bonding is shown to be crucial in the relative free energies of different conformers.

  2. Development of Swimming Human Simulation Model Considering Rigid Body Dynamics and Unsteady Fluid Force for Whole Body

    Science.gov (United States)

    Nakashima, Motomu; Satou, Ken; Miura, Yasufumi

    The purpose of this study is to develop a swimming human simulation model considering rigid body dynamics and unsteady fluid force for the whole body, which will be utilized to analyze various dynamical problems in human swimming. First, the modeling methods and their formulations for the human body and the fluid force are respectively described. Second, experiments to identify the coefficients of the normal drag and the added mass are conducted by use of an experimental setup, in which a limb model rotates in the water, and its rotating angle and the bending moment at the root are measured. As the result of the identification, the present model for the fluid force was found to have satisfactory performance in order to represent the unsteady fluctuations of the experimental data, although it has 10% error. Third, a simulation for the gliding position is conducted in order to identify the tangential drag coefficient. Finally, a simulation example of standard six beat front crawl swimming is shown. The swimming speed of the simulation became a reasonable value, indicating the validity of the present simulation model, although it is 7.5% lower than the actual swimming.

  3. iCub Whole-body Control through Force Regulation on Rigid Noncoplanar Contacts

    Directory of Open Access Journals (Sweden)

    Francesco eNori

    2015-03-01

    Full Text Available This paper details the implementation on the humanoid robot iCub of state-of-the-art algorithms for whole-body control. We regulate the forces between the robot and its surrounding environment to stabilize a desired robot posture. We assume that the forces and torques are exerted on rigid contacts. The validity of this assumption is guaranteed by constraining the contact forces and torques, e.g. the contact forces must belong to the associated friction cones. The implementation of this control strategy requires to estimate the external forces acting on the robot, and the internal joint torques. We then detail algorithms to obtain these estimations when using a robot with an iCub-like sensor set, i.e. distributed six-axis force-torque sensors and whole-body tactile sensors. A general theory for identifying the robot inertial parameters is also presented. From an actuation standpoint, we show how to implement a joint torque control in the case of DC brushless motors. In addition, the coupling mechanism of the iCub torso is investigated. The soundness of the entire control architecture is validated in a real scenario involving the robot iCub balancing and making contacts at both arms.

  4. Effect of chain rigidity on network architecture and deformation behavior of glassy polymer networks

    Science.gov (United States)

    Knowles, Kyler Reser

    alter the physical, volumetric, and mechanical properties of the glassy networks. Chain rigidity was found to directly control deformation mechanisms, which were related to the yielding behavior of the epoxy network series. The unique benefit to our approach is the ability to separate the role of rigidity - an intramolecular parameter - from intermolecular phenomena which otherwise influence network properties.

  5. Curvilinear immersed boundary method for simulating fluid structure interaction with complex 3D rigid bodies

    Science.gov (United States)

    Borazjani, Iman; Ge, Liang; Sotiropoulos, Fotis

    2008-08-01

    The sharp-interface CURVIB approach of Ge and Sotiropoulos [L. Ge, F. Sotiropoulos, A numerical method for solving the 3D unsteady incompressible Navier-Stokes equations in curvilinear domains with complex immersed boundaries, Journal of Computational Physics 225 (2007) 1782-1809] is extended to simulate fluid structure interaction (FSI) problems involving complex 3D rigid bodies undergoing large structural displacements. The FSI solver adopts the partitioned FSI solution approach and both loose and strong coupling strategies are implemented. The interfaces between immersed bodies and the fluid are discretized with a Lagrangian grid and tracked with an explicit front-tracking approach. An efficient ray-tracing algorithm is developed to quickly identify the relationship between the background grid and the moving bodies. Numerical experiments are carried out for two FSI problems: vortex induced vibration of elastically mounted cylinders and flow through a bileaflet mechanical heart valve at physiologic conditions. For both cases the computed results are in excellent agreement with benchmark simulations and experimental measurements. The numerical experiments suggest that both the properties of the structure (mass, geometry) and the local flow conditions can play an important role in determining the stability of the FSI algorithm. Under certain conditions the FSI algorithm is unconditionally unstable even when strong coupling FSI is employed. For such cases, however, combining the strong coupling iteration with under-relaxation in conjunction with the Aitken's acceleration technique is shown to effectively resolve the stability problems. A theoretical analysis is presented to explain the findings of the numerical experiments. It is shown that the ratio of the added mass to the mass of the structure as well as the sign of the local time rate of change of the force or moment imparted on the structure by the fluid determine the stability and convergence of the FSI

  6. On the motion of rigid bodies in an incompressible or compressible viscous fluid under the action of gravitational forces

    Czech Academy of Sciences Publication Activity Database

    Ducomet, B.; Nečasová, Šárka

    2013-01-01

    Roč. 6, č. 5 (2013), s. 1193-1213 ISSN 1937-1632 R&D Projects: GA ČR(CZ) GAP201/11/1304 Institutional support: RVO:67985840 Keywords : motion of rigid bodies * incompressible fluid * compressible fluid Subject RIV: BA - General Mathematics https://www.aimsciences.org/journals/displayArticlesnew.jsp?paperID=8331

  7. An iterative approach to dynamic simulation of 3D rigid body motions for real-time interactive computer animation

    NARCIS (Netherlands)

    Overveld, van C.W.A.M.

    1991-01-01

    A method is presented for approximating the motions of linked 3-dimensional rigid body systems that may be applied in the context of interactive motion specification for computer animation. The method is based on decoupling the ballistic (free) component of the motion of the points that constitute

  8. Case report: Inhaled foreign body mismanaged as TB, finally removed using a rigid bronchoscopy after 6 years of impaction

    Directory of Open Access Journals (Sweden)

    Justin Rubena Lumaya

    2016-02-01

    Full Text Available Foreign body aspiration is an important cause of mortality in children aged less than three years. Foreign body (FB inhalation can pose diagnostic and therapeutic challenges, especially in longstanding cases and complications such as recurrent pneumonia, lung collapse and lung abscess may develop. We report a case of an 11-year old boy with foreign body impacted in his bronchus for six years, which was mistakenly managed as pulmonary tuberculosis. Radiological evidence confirmed the diagnosis and a rigid bronchoscopy was used to remove the metallic foreign body. The standard of care for the management of a FB in a bronchus is a rigid bronchoscopy; however flexible bronchoscopy can be used, especially in adults. A thorough history with radiological evidence are essential and sometimes, followed by a diagnostic bronchoscopy.

  9. A navigator-based rigid body motion correction for magnetic resonance imaging

    International Nuclear Information System (INIS)

    Ullisch, Marcus Goerge

    2012-01-01

    A novel three-dimensional navigator k-space trajectory for rigid body motion detection for Magnetic Resonance Imaging (MRI) - the Lissajous navigator - was developed and quantitatively compared to the existing spherical navigator trajectory [1]. The spherical navigator cannot sample the complete spherical surface due to slew rate limitations of the scanner hardware. By utilizing a two dimensional Lissajous figure which is projected onto the spherical surface, the Lissajous navigator overcomes this limitation. The complete sampling of the sphere consequently leads to rotation estimates with higher and more isotropic accuracy. Simulations and phantom measurements were performed for both navigators. Both simulations and measurements show a significantly higher overall accuracy of the Lissajous navigator and a higher isotropy of the rotation estimates. Measured under identical conditions with identical postprocessing, the measured mean absolute error of the rotation estimates for the Lissajous navigator was 38% lower (0.3 ) than for the spherical navigator (0.5 ). The maximum error of the Lissajous navigator was reduced by 48% relative to the spherical navigator. The Lissajous navigator delivers higher accuracy of rotation estimation and a higher degree of isotropy than the spherical navigator with no evident drawbacks; these are two decisive advantages, especially for high-resolution anatomical imaging.

  10. Fullrmc, a rigid body Reverse Monte Carlo modeling package enabled with machine learning and artificial intelligence.

    Science.gov (United States)

    Aoun, Bachir

    2016-05-05

    A new Reverse Monte Carlo (RMC) package "fullrmc" for atomic or rigid body and molecular, amorphous, or crystalline materials is presented. fullrmc main purpose is to provide a fully modular, fast and flexible software, thoroughly documented, complex molecules enabled, written in a modern programming language (python, cython, C and C++ when performance is needed) and complying to modern programming practices. fullrmc approach in solving an atomic or molecular structure is different from existing RMC algorithms and software. In a nutshell, traditional RMC methods and software randomly adjust atom positions until the whole system has the greatest consistency with a set of experimental data. In contrast, fullrmc applies smart moves endorsed with reinforcement machine learning to groups of atoms. While fullrmc allows running traditional RMC modeling, the uniqueness of this approach resides in its ability to customize grouping atoms in any convenient way with no additional programming efforts and to apply smart and more physically meaningful moves to the defined groups of atoms. In addition, fullrmc provides a unique way with almost no additional computational cost to recur a group's selection, allowing the system to go out of local minimas by refining a group's position or exploring through and beyond not allowed positions and energy barriers the unrestricted three dimensional space around a group. © 2016 Wiley Periodicals, Inc.

  11. A navigator-based rigid body motion correction for magnetic resonance imaging

    Energy Technology Data Exchange (ETDEWEB)

    Ullisch, Marcus Goerge

    2012-01-24

    A novel three-dimensional navigator k-space trajectory for rigid body motion detection for Magnetic Resonance Imaging (MRI) - the Lissajous navigator - was developed and quantitatively compared to the existing spherical navigator trajectory [1]. The spherical navigator cannot sample the complete spherical surface due to slew rate limitations of the scanner hardware. By utilizing a two dimensional Lissajous figure which is projected onto the spherical surface, the Lissajous navigator overcomes this limitation. The complete sampling of the sphere consequently leads to rotation estimates with higher and more isotropic accuracy. Simulations and phantom measurements were performed for both navigators. Both simulations and measurements show a significantly higher overall accuracy of the Lissajous navigator and a higher isotropy of the rotation estimates. Measured under identical conditions with identical postprocessing, the measured mean absolute error of the rotation estimates for the Lissajous navigator was 38% lower (0.3 ) than for the spherical navigator (0.5 ). The maximum error of the Lissajous navigator was reduced by 48% relative to the spherical navigator. The Lissajous navigator delivers higher accuracy of rotation estimation and a higher degree of isotropy than the spherical navigator with no evident drawbacks; these are two decisive advantages, especially for high-resolution anatomical imaging.

  12. Generalized Predictive Control of Dynamic Systems with Rigid-Body Modes

    Science.gov (United States)

    Kvaternik, Raymond G.

    2013-01-01

    Numerical simulations to assess the effectiveness of Generalized Predictive Control (GPC) for active control of dynamic systems having rigid-body modes are presented. GPC is a linear, time-invariant, multi-input/multi-output predictive control method that uses an ARX model to characterize the system and to design the controller. Although the method can accommodate both embedded (implicit) and explicit feedforward paths for incorporation of disturbance effects, only the case of embedded feedforward in which the disturbances are assumed to be unknown is considered here. Results from numerical simulations using mathematical models of both a free-free three-degree-of-freedom mass-spring-dashpot system and the XV-15 tiltrotor research aircraft are presented. In regulation mode operation, which calls for zero system response in the presence of disturbances, the simulations showed reductions of nearly 100%. In tracking mode operations, where the system is commanded to follow a specified path, the GPC controllers produced the desired responses, even in the presence of disturbances.

  13. Modeling meniscus rise in capillary tubes using fluid in rigid-body motion approach

    Science.gov (United States)

    Hamdan, Mohammad O.; Abu-Nabah, Bassam A.

    2018-04-01

    In this study, a new term representing net flux rate of linear momentum is introduced to Lucas-Washburn equation. Following a fluid in rigid-body motion in modeling the meniscus rise in vertical capillary tubes transforms the nonlinear Lucas-Washburn equation to a linear mass-spring-damper system. The linear nature of mass-spring-damper system with constant coefficients offers a nondimensional analytical solution where meniscus dynamics are dictated by two parameters, namely the system damping ratio and its natural frequency. This connects the numerous fluid-surface interaction physical and geometrical properties to rather two nondimensional parameters, which capture the underlying physics of meniscus dynamics in three distinct cases, namely overdamped, critically damped, and underdamped systems. Based on experimental data available in the literature and the understanding meniscus dynamics, the proposed model brings a new approach of understanding the system initial conditions. Accordingly, a closed form relation is produced for the imbibition velocity, which equals half of the Bosanquet velocity divided by the damping ratio. The proposed general analytical model is ideal for overdamped and critically damped systems. While for underdamped systems, the solution shows fair agreement with experimental measurements once the effective viscosity is determined. Moreover, the presented model shows meniscus oscillations around equilibrium height occur if the damping ratio is less than one.

  14. Diffuse interface immersed boundary method for multi-fluid flows with arbitrarily moving rigid bodies

    Science.gov (United States)

    Patel, Jitendra Kumar; Natarajan, Ganesh

    2018-05-01

    We present an interpolation-free diffuse interface immersed boundary method for multiphase flows with moving bodies. A single fluid formalism using the volume-of-fluid approach is adopted to handle multiple immiscible fluids which are distinguished using the volume fractions, while the rigid bodies are tracked using an analogous volume-of-solid approach that solves for the solid fractions. The solution to the fluid flow equations are carried out using a finite volume-immersed boundary method, with the latter based on a diffuse interface philosophy. In the present work, we assume that the solids are filled with a "virtual" fluid with density and viscosity equal to the largest among all fluids in the domain. The solids are assumed to be rigid and their motion is solved using Newton's second law of motion. The immersed boundary methodology constructs a modified momentum equation that reduces to the Navier-Stokes equations in the fully fluid region and recovers the no-slip boundary condition inside the solids. An implicit incremental fractional-step methodology in conjunction with a novel hybrid staggered/non-staggered approach is employed, wherein a single equation for normal momentum at the cell faces is solved everywhere in the domain, independent of the number of spatial dimensions. The scalars are all solved for at the cell centres, with the transport equations for solid and fluid volume fractions solved using a high-resolution scheme. The pressure is determined everywhere in the domain (including inside the solids) using a variable coefficient Poisson equation. The solution to momentum, pressure, solid and fluid volume fraction equations everywhere in the domain circumvents the issue of pressure and velocity interpolation, which is a source of spurious oscillations in sharp interface immersed boundary methods. A well-balanced algorithm with consistent mass/momentum transport ensures robust simulations of high density ratio flows with strong body forces. The

  15. Comparison of rigid and flexible endoscopy for removing esophageal foreign bodies in an emergency.

    Science.gov (United States)

    Tseng, Chia-Chen; Hsiao, Tzu-Yu; Hsu, Wei-Chung

    2016-08-01

    Despite the effectiveness of endoscopies in removing ingested foreign bodies (FBs) impacted in the esophagus, the merits and limitations of flexible endoscopy (FE) and rigid endoscopy (RE) remain unclear. Therefore, this study compares the advantages and disadvantages of both endoscopic procedures from a clinical perspective. A retrospective review was made of 273 patients suspected of esophageal FBs in emergency consultations of a tertiary medical referral center from March 2010 to March 2014. All patients received routine physical examinations, otolaryngological examinations, and X-rays of the neck and chest. The door-to-endoscopy time, procedure time, postendoscopic hospital stay, successful removal rates, and complications were analyzed as well. In this study, the most common esophageal FBs were fish and animal bones (76%) in adults and coins (74%) in children. The patients with existing esophageal FBs had significantly more frequent symptoms of dysphagia and signs of linear opacity as detected with lateral neck radiography than those without FB. Additionally, the door-to-endoscopy time, procedure time, and postendoscopic hospital stay was significantly shorter in FE patients than in RE patients. However, both RE and FE patients had high rates of successful FB removal (95%) and low complication rates (2%). Both FE and RE remove esophageal FBs successfully, as evidenced by their high success rates, low complication rates, and high detection rates. Although FE under local anesthesia is a less time-consuming procedure for adults, RE under general anesthesia may be preferable for children and can serve as an alternative to FE. Copyright © 2015. Published by Elsevier B.V.

  16. Strongly coupled partitioned six degree-of-freedom rigid body motion solver with Aitken's dynamic under-relaxation

    Directory of Open Access Journals (Sweden)

    Jeng Hei Chow

    2016-07-01

    Full Text Available An implicit method of solving the six degree-of-freedom rigid body motion equations based on the second order Adams-Bashforth-Moulten method was utilised as an improvement over the leapfrog scheme by making modifications to the rigid body motion solver libraries directly. The implementation will depend on predictor-corrector steps still residing within the hybrid Pressure Implicit with Splitting of Operators - Semi-Implicit Method for Pressure Linked Equations (PIMPLE outer corrector loops to ensure strong coupling between fluid and motion. Aitken's under-relaxation is also introduced in this study to optimise the convergence rate and stability of the coupled solver. The resulting coupled solver ran on a free floating object tutorial test case when converged matches the original solver. It further allows a varying 70%–80% reduction in simulation times compared using a fixed under-relaxation to achieve the required stability.

  17. HOW CAN DYNAMIC RIGID-BODY MODELING BE HELPFUL IN MOTOR LEARNING? - DIAGNOSING PERFORMANCE USING DYNAMIC MODELING

    OpenAIRE

    Shan, Gongbing; Sust, Martin; Simard, Stephane; Bohn, Christina; Nicol, Klaus

    2004-01-01

    There are two main problems for biomechanists in motor learning practice. One is theory vs. experience, the other is the determination of dominative information directly helpful in the practice. This project aimed at addressing these problems from a quantitative aspect by using motion capture and biomechanical rigid body modeling. The purposes were to identify differences in the description of movements amongst motion analysists (external view), athletes (internal sight) and coaches (internal...

  18. Digital anthropomorphic phantoms of non-rigid human respiratory and voluntary body motion for investigating motion correction in emission imaging

    International Nuclear Information System (INIS)

    Könik, Arda; Johnson, Karen L; Dasari, Paul; Pretorius, P H; Dey, Joyoni; King, Michael A; Connolly, Caitlin M; Segars, Paul W; Lindsay, Clifford

    2014-01-01

    The development of methods for correcting patient motion in emission tomography has been receiving increased attention. Often the performance of these methods is evaluated through simulations using digital anthropomorphic phantoms, such as the commonly used extended cardiac torso (XCAT) phantom, which models both respiratory and cardiac motion based on human studies. However, non-rigid body motion, which is frequently seen in clinical studies, is not present in the standard XCAT phantom. In addition, respiratory motion in the standard phantom is limited to a single generic trend. In this work, to obtain a more realistic representation of motion, we developed a series of individual-specific XCAT phantoms, modeling non-rigid respiratory and non-rigid body motions derived from the magnetic resonance imaging (MRI) acquisitions of volunteers. Acquisitions were performed in the sagittal orientation using the Navigator methodology. Baseline (no motion) acquisitions at end-expiration were obtained at the beginning of each imaging session for each volunteer. For the body motion studies, MRI was again acquired only at end-expiration for five body motion poses (shoulder stretch, shoulder twist, lateral bend, side roll, and axial slide). For the respiratory motion studies, an MRI was acquired during free/regular breathing. The magnetic resonance slices were then retrospectively sorted into 14 amplitude-binned respiratory states, end-expiration, end-inspiration, six intermediary states during inspiration, and six during expiration using the recorded Navigator signal. XCAT phantoms were then generated based on these MRI data by interactive alignment of the organ contours of the XCAT with the MRI slices using a graphical user interface. Thus far we have created five body motion and five respiratory motion XCAT phantoms from the MRI acquisitions of six healthy volunteers (three males and three females). Non-rigid motion exhibited by the volunteers was reflected in both respiratory

  19. Digital anthropomorphic phantoms of non-rigid human respiratory and voluntary body motion for investigating motion correction in emission imaging

    Science.gov (United States)

    Könik, Arda; Connolly, Caitlin M.; Johnson, Karen L.; Dasari, Paul; Segars, Paul W.; Pretorius, P. H.; Lindsay, Clifford; Dey, Joyoni; King, Michael A.

    2014-07-01

    The development of methods for correcting patient motion in emission tomography has been receiving increased attention. Often the performance of these methods is evaluated through simulations using digital anthropomorphic phantoms, such as the commonly used extended cardiac torso (XCAT) phantom, which models both respiratory and cardiac motion based on human studies. However, non-rigid body motion, which is frequently seen in clinical studies, is not present in the standard XCAT phantom. In addition, respiratory motion in the standard phantom is limited to a single generic trend. In this work, to obtain a more realistic representation of motion, we developed a series of individual-specific XCAT phantoms, modeling non-rigid respiratory and non-rigid body motions derived from the magnetic resonance imaging (MRI) acquisitions of volunteers. Acquisitions were performed in the sagittal orientation using the Navigator methodology. Baseline (no motion) acquisitions at end-expiration were obtained at the beginning of each imaging session for each volunteer. For the body motion studies, MRI was again acquired only at end-expiration for five body motion poses (shoulder stretch, shoulder twist, lateral bend, side roll, and axial slide). For the respiratory motion studies, an MRI was acquired during free/regular breathing. The magnetic resonance slices were then retrospectively sorted into 14 amplitude-binned respiratory states, end-expiration, end-inspiration, six intermediary states during inspiration, and six during expiration using the recorded Navigator signal. XCAT phantoms were then generated based on these MRI data by interactive alignment of the organ contours of the XCAT with the MRI slices using a graphical user interface. Thus far we have created five body motion and five respiratory motion XCAT phantoms from the MRI acquisitions of six healthy volunteers (three males and three females). Non-rigid motion exhibited by the volunteers was reflected in both respiratory

  20. Body weight perception and body weight control behaviors in adolescents

    OpenAIRE

    Frank, Robson; Claumann, Gaia S.; Felden, Érico P.G.; Silva, Diego A.S.; Pelegrini, Andreia

    2018-01-01

    Abstract Objective: To investigate the association between the perception of body weight (as above or below the desired) and behaviors for body weight control in adolescents. Methods: This was a cross-sectional study that included 1051 adolescents (aged 15-19 years) who were high school students attending public schools. The authors collected information on the perception of body weight (dependent variable), weight control behaviors (initiative to change the weight, physical exercise, eatin...

  1. Self-propulsion of a body with rigid surface and variable coefficient of lift in a perfect fluid

    Science.gov (United States)

    Ramodanov, Sergey M.; Tenenev, Valentin A.; Treschev, Dmitry V.

    2012-11-01

    We study the system of a 2D rigid body moving in an unbounded volume of incompressible, vortex-free perfect fluid which is at rest at infinity. The body is equipped with a gyrostat and a so-called Flettner rotor. Due to the latter the body is subject to a lifting force (Magnus effect). The rotational velocities of the gyrostat and the rotor are assumed to be known functions of time (control inputs). The equations of motion are presented in the form of the Kirchhoff equations. The integrals of motion are given in the case of piecewise continuous control. Using these integrals we obtain a (reduced) system of first-order differential equations on the configuration space. Then an optimal control problem for several types of the inputs is solved using genetic algorithms.

  2. Quantum chemical approach for condensed-phase thermochemistry (V): Development of rigid-body type harmonic solvation model

    Science.gov (United States)

    Tarumi, Moto; Nakai, Hiromi

    2018-05-01

    This letter proposes an approximate treatment of the harmonic solvation model (HSM) assuming the solute to be a rigid body (RB-HSM). The HSM method can appropriately estimate the Gibbs free energy for condensed phases even where an ideal gas model used by standard quantum chemical programs fails. The RB-HSM method eliminates calculations for intra-molecular vibrations in order to reduce the computational costs. Numerical assessments indicated that the RB-HSM method can evaluate entropies and internal energies with the same accuracy as the HSM method but with lower calculation costs.

  3. A biomechanical testing system to determine micromotion between hip implant and femur accounting for deformation of the hip implant: Assessment of the influence of rigid body assumptions on micromotions measurements.

    Science.gov (United States)

    Leuridan, Steven; Goossens, Quentin; Roosen, Jorg; Pastrav, Leonard; Denis, Kathleen; Mulier, Michiel; Desmet, Wim; Vander Sloten, Jos

    2017-02-01

    Accurate pre-clinical evaluation of the initial stability of new cementless hip stems using in vitro micromotion measurements is an important step in the design process to assess the new stem's potential. Several measuring systems, linear variable displacement transducer-based and other, require assuming bone or implant to be rigid to obtain micromotion values or to calculate derived quantities such as relative implant tilting. An alternative linear variable displacement transducer-based measuring system not requiring a rigid body assumption was developed in this study. The system combined advantages of local unidirectional and frame-and-bracket micromotion measuring concepts. The influence and possible errors that would be made by adopting a rigid body assumption were quantified. Furthermore, as the system allowed emulating local unidirectional and frame-and-bracket systems, the influence of adopting rigid body assumptions were also analyzed for both concepts. Synthetic and embalmed bone models were tested in combination with primary and revision implants. Single-legged stance phase loading was applied to the implant - bone constructs. Adopting a rigid body assumption resulted in an overestimation of mediolateral micromotion of up to 49.7μm at more distal measuring locations. Maximal average relative rotational motion was overestimated by 0.12° around the anteroposterior axis. Frontal and sagittal tilting calculations based on a unidirectional measuring concept underestimated the true tilting by an order of magnitude. Non-rigid behavior is a factor that should not be dismissed in micromotion stability evaluations of primary and revision femoral implants. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Poisson equations of rotational motion for a rigid triaxial body with application to a tumbling artificial satellite

    Science.gov (United States)

    Liu, J. J. F.; Fitzpatrick, P. M.

    1975-01-01

    A mathematical model is developed for studying the effects of gravity gradient torque on the attitude stability of a tumbling triaxial rigid satellite. Poisson equations are used to investigate the rotation of the satellite (which is in elliptical orbit about an attracting point mass) about its center of mass. An averaging method is employed to obtain an intermediate set of differential equations for the nonresonant, secular behavior of the osculating elements which describe the rotational motions of the satellite, and the averaged equations are then integrated to obtain long-term secular solutions for the osculating elements.

  5. Rigid-body rotation of an electron cloud in divergent magnetic fields

    International Nuclear Information System (INIS)

    Fruchtman, A.; Gueroult, R.; Fisch, N. J.

    2013-01-01

    For a given voltage across a divergent poloidal magnetic field, two electric potential distributions, each supported by a rigid-rotor electron cloud rotating with a different frequency, are found analytically. The two rotation frequencies correspond to the slow and fast rotation frequencies known in uniform plasma. Due to the centrifugal force, the equipotential surfaces, that correspond to the two electric potential distributions, diverge more than the magnetic surfaces do, the equipotential surfaces in the fast mode diverge largely in particular. The departure of the equipotential surfaces from the magnetic field surfaces may have a significant focusing effect on the ions accelerated by the electric field. The focusing effect could be important for laboratory plasma accelerators as well as for collimation of astrophysical jets

  6. An investigation on the effect of gusset plate connection rigidity on the seismic behavior of special concentrically braced frames

    Directory of Open Access Journals (Sweden)

    Ali Esnaashari

    2016-12-01

    Full Text Available Special concentrically braced frames (SCBFs are commonly used to resist lateral loads in buildings. The bracing system sustains large deformations due to inelastic behavior in bracing members (buckling and yielding in tension. Generally, in the conventional modeling strategy, the effect of gusset plates in providing beam-column connections rigidity and hence, improving the post-buckling performance of these frames is not taken into account. This paper deals with the effect of gusset plate rigidity on the seismic behavior of SCBFs using Roeder’s proposed model in the literature. In this paper, four 3, 6, 9 and 12-story SCBFs were designed and modeled using two distinct methods: conventional method with hinged connections and Roeder’s method with semi-rigid connections. Then, the models behavior was investigated with both pushover analysis and nonlinear time-history analysis using OpenSees software. The results showed that lateral load capacity of the frames modeled with the Roeder’s proposed model are about 10% larger than the conventional method’s capacity. Also, it was found that the semi-rigid model leads to a less drift ratios and more overstrength factors.

  7. Flutter Analysis of RX-420 Balistic Rocket Fin Involving Rigid Body Modes of Rocket Structures

    Directory of Open Access Journals (Sweden)

    Novi Andria

    2013-03-01

    Full Text Available Flutter is a phenomenon that has brought a catastrophic failure to the flight vehicle structure. In this experiment, flutter was analyzed for its symmetric and antisymmetric configuration to understand the effect of rocket rigid modes to the fin flutter characteristic. This research was also expected to find out the safety level of RX-420 structure design. The analysis was performed using half rocket model. Fin structure used in this research was a fin which has semispan 600 mm, thickness 12 mm, chord root 700 mm, chord tip 400 mm, made by Al 6061-T651, double spar configuration with skin thickness of 2 mm. Structural dynamics and flutter stability were analyzed using finite element software implemented on MSC. Nastran. The analysis shows that the antisymmetric flutter mode is more critical than symmetric flutter mode. At sea level altitude, antisymmetric flutter occurs at 6.4 Mach, and symmetric flutter occurs at 10.15 Mach. Compared to maximum speed of RX-420 which is 4.5 Mach at altitude 11 km or equivalent to 2.1 Mach at sea level, it can be concluded that the RX-420 structure design is safe, and flutter will not occur during flight.

  8. Knowledge-in-action: a study on the integration of forces and energy in a rigid body

    Directory of Open Access Journals (Sweden)

    Consuelo Escudero

    2009-03-01

    Full Text Available This paper intends to go on with the study of problem solving in a compatible way with the theories of conceptual fields (TCC of Vergnaud (1990,1994,1998 and mental models of Johnson-Laird (1983,1990. Together with findings of another study (Escudero & Jaime 2007, some achievements and difficulties of freshmore engineering students when solving problems of the motion of rigid body in terms of the knowledge-in-action are analysed. The research methodology under a qualitative paradigm grouped data into categories which are not provided a priori by the theoretical framework. It can be said that the quality of the conceptual representation has been explicit in the quality of the proposed solution. Some meanings introduced by students in their problem solving activities can be characterized as operational invariants.

  9. Analysis of the Gyroscopic Stabilization of a System of Rigid Bodies

    DEFF Research Database (Denmark)

    Kliem, Wolfhard; Kliem, Wolfhard

    1996-01-01

    We study the gyroscopic of a three-body system. A new method offinding stability regions, based on mechanism and criteria for gyroscopicstabilization, is presented. Of particular interest in this connection isthe theory of interaction of eigenvalues. This leads to a complete 3-dimensionalanalysis......, which shows the regions of stability, divergence, and flutter ofa simple model of a rotating spaceship....

  10. Equilibria of the three-body problem with rigid dumb-bell satellite

    International Nuclear Information System (INIS)

    Elipe, A.; Palacios, M.; Pretka-Ziomek, H.

    2008-01-01

    This paper is concerned with the orbital-rotational motion of an asymmetric dumb-bell (two masses with fixed distance among them) under the attraction of a central body. For this model, we find some equilibria and give sufficient conditions for their stability

  11. Estimating the angular velocity of a rigid body moving in the plane from tangential and centripetal acceleration measurements

    International Nuclear Information System (INIS)

    Cardou, Philippe; Angeles, Jorge

    2008-01-01

    Two methods are available for the estimation of the angular velocity of a rigid body from point-acceleration measurements: (i) the time-integration of the angular acceleration and (ii) the square-rooting of the centripetal acceleration. The inaccuracy of the first method is due mainly to the accumulation of the error on the angular acceleration throughout the time-integration process, which does not prevent that it be used successfully in crash tests with dummies, since these experiments never last more than one second. On the other hand, the error resulting from the second method is stable through time, but becomes inaccurate whenever the rigid body angular velocity approaches zero, which occurs in many applications. In order to take advantage of the complementarity of these two methods, a fusion of their estimates is proposed. To this end, the accelerometer measurements are modeled as exact signals contaminated with bias errors and Gaussian white noise. The relations between the variables at stake are written in the form of a nonlinear state-space system in which the angular velocity and the angular acceleration are state variables. Consequently, a minimum-variance-error estimate of the state vector is obtained by means of extended Kalman filtering. The performance of the proposed estimation method is assessed by means of simulation. Apparently, the resulting estimation method is more robust than the existing accelerometer-only methods and competitive with gyroscope measurements. Moreover, it allows the identification and the compensation of any bias error in the accelerometer measurements, which is a significant advantage over gyroscopes

  12. The effect of the lateral interactions on the critical behavior of long straight rigid rods on two-dimensional lattices

    Directory of Open Access Journals (Sweden)

    A. J. Ramirez-Pastor

    2009-09-01

    Full Text Available Using Monte Carlo simulations and finite-size scaling analysis, the critical behavior of attractive rigid rods of length $k$ ($k$-mers on square lattices at intermediate density has been studied. A nematic phase, characterized by a big domain of parallel $k$-mers, was found. This ordered phase is separated from the isotropic state by a continuous transition occurring at a intermediate density $heta_c$, which increases linearly with the magnitude of the lateral interactions.

  13. A new method using insert-based systems (IBS) to improve cell behavior study on flexible and rigid biomaterials

    OpenAIRE

    Grenade, Charlotte; Moniotte, Nicolas; Rompen, Eric; Vanheusden, Alain; Mainjot, Amélie; De Pauw-Gillet, Marie-Claire

    2016-01-01

    In vitro studies about biomaterials biological properties are essential screening tests. Yet cell cultures encounter difficulties related to cell retention on material surface or to the observation of both faces of permeable materials. The objective of the present study was to develop a reliable in vitro method to study cell behavior on rigid and flexible/permeable biomaterials elaborating two specific insert-based systems (IBS-R and IBS-F respectively). IBS-R was designed as a specific cylin...

  14. Cognitive-Behavioral Body Image Therapy for Body Dysmorphic Disorder.

    Science.gov (United States)

    Rosen, James C.; And Others

    1995-01-01

    Randomly assigned 54 body dysmorphic disorder (BDD) subjects to cognitive behavior therapy or no treatment. BDD symptoms were significantly decreased in therapy subjects and the disorder was eliminated in 82 percent of cases at posttreatment and 77 percent at follow-up. Subjects' overall psychological symptoms and self-esteem also improved. (RJM)

  15. On the axioms of the forces in the mechanics of rigid bodies

    Directory of Open Access Journals (Sweden)

    Lámer Géza

    2017-01-01

    Full Text Available Newton summarised knowledge related to forces in three axioms. The first and second ones define the mechanical state and motion of the examined body when there is no force or when force is exerted on the body. The third defines the law of action and reaction. Newton did not define it as separate axiom but assumed that forces are completely independent from each other. The statics applies four axioms. The first applies to the balance of two forces while the second one applies of three forces. The third axiom defines the relationships inside an equilibrium force system. The fourth one is the axiom of action and reaction. The two axiom systems are independent from each other. Further the independent axioms are applied in case of constraint forces: frictionless reaction force orthogonal on the forced surface, friction force acts in the direction of the motion, the deformation can be elastic, plastic and viscous.

  16. Analysis of the gyroscopic stabilization of a system of rigid bodies

    DEFF Research Database (Denmark)

    Kliem, Wolfhard; Seyranian, Alexander P.

    1997-01-01

    We study the gyroscopic stability of a three-body system. A new method of finding stability regions, based on mechanism and criteria for gyroscopic stabilization, is presented. Of particular interest in this connection is the theory of interaction of eigenvalues. This leads to a complete 3......-dimensional analysis, which shows the regions of stability, divergence, and flutter of a simple model of a rotating spaceship....

  17. Free surface flow with moving rigid bodies. Part 1. Computational flow model

    International Nuclear Information System (INIS)

    Gubanov, O.I.; Mironova, L.A.; Kocabiyik, S.

    2005-01-01

    This paper was motivated by the study of Hirt and Sicilian, where the 'differential form' of the governing equations for the inviscid fluid flow (FAVOR equations) were obtained. We utilize mainly generalized differentiation to extend the Reynolds transport theorem over a control volume containing fluid interface for deriving the 'integral form' of governing equations for the incompressible viscous flow problems. This is done following the work by Farassat and the use of generalized function theory made this derivation straightforward, systematic and rigorous. The resulting equations are discretized by a finite-volume method using a staggered grid, after making use of the coarse-scale approximation. The resulting governing equations are valid for a class of flows including free surface flows with arbitrarily moving bodies and are consistent with Hirt and Sicilian's formulation in the inviscid fluid flow case. (author)

  18. Rigid dietary control, flexible dietary control, and intuitive eating: Evidence for their differential relationship to disordered eating and body image concerns.

    Science.gov (United States)

    Linardon, Jake; Mitchell, Sarah

    2017-08-01

    This study aimed to replicate and extend from Tylka, Calogero, and Daníelsdóttir (2015) findings by examining the relationship between rigid control, flexible control, and intuitive eating on various indices of disordered eating (i.e., binge eating, disinhibition) and body image concerns (i.e., shape and weight over-evaluation, body checking, and weight-related exercise motivations). This study also examined whether the relationship between intuitive eating and outcomes was mediated by dichotomous thinking and body appreciation. Analysing data from a sample of 372 men and women recruited through the community, this study found that, in contrast to rigid dietary control, intuitive eating uniquely and consistently predicted lower levels of disordered eating and body image concerns. This intuitive eating-disordered eating relationship was mediated by low levels of dichotomous thinking and the intuitive eating-body image relationship was mediated by high levels of body appreciation. Flexible control predicted higher levels of body image concerns and lower levels of disordered eating only when rigid control was accounted for. Findings suggest that until the adaptive properties of flexible control are further elucidated, it may be beneficial to promote intuitive eating within public health approaches to eating disorder prevention. In addition to this, particular emphasis should also be made toward promoting body acceptance and eradicating a dichotomous thinking style around food and eating. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Rigid Body Attitude Control Based on a Manifold Representation of Direction Cosine Matrices

    International Nuclear Information System (INIS)

    Nakath, David; Clemens, Joachim; Rachuy, Carsten

    2017-01-01

    Autonomous systems typically actively observe certain aspects of their surroundings, which makes them dependent on a suitable controller. However, building an attitude controller for three degrees of freedom is a challenging task, mainly due to singularities in the different parametrizations of the three dimensional rotation group SO (3). Thus, we propose an attitude controller based on a manifold representation of direction cosine matrices: In state space, the attitude is globally and uniquely represented as a direction cosine matrix R ∈ SO (3). However, differences in the state space, i.e., the attitude errors, are exposed to the controller in the vector space ℝ 3 . This is achieved by an operator, which integrates the matrix logarithm mapping from SO (3) to so(3) and the map from so(3) to ℝ 3 . Based on this representation, we derive a proportional and derivative feedback controller, whose output has an upper bound to prevent actuator saturation. Additionally, the feedback is preprocessed by a particle filter to account for measurement and state transition noise. We evaluate our approach in a simulator in three different spacecraft maneuver scenarios: (i) stabilizing, (ii) rest-to-rest, and (iii) nadir-pointing. The controller exhibits stable behavior from initial attitudes near and far from the setpoint. Furthermore, it is able to stabilize a spacecraft and can be used for nadir-pointing maneuvers. (paper)

  20. A finite element model of rigid body structures actuated by dielectric elastomer actuators

    Science.gov (United States)

    Simone, F.; Linnebach, P.; Rizzello, G.; Seelecke, S.

    2018-06-01

    This paper presents on finite element (FE) modeling and simulation of dielectric elastomer actuators (DEAs) coupled with articulated structures. DEAs have proven to represent an effective transduction technology for the realization of large deformation, low-power consuming, and fast mechatronic actuators. However, the complex dynamic behavior of the material, characterized by nonlinearities and rate-dependent phenomena, makes it difficult to accurately model and design DEA systems. The problem is further complicated in case the DEA is used to activate articulated structures, which increase both system complexity and implementation effort of numerical simulation models. In this paper, we present a model based tool which allows to effectively implement and simulate complex articulated systems actuated by DEAs. A first prototype of a compact switch actuated by DEA membranes is chosen as reference study to introduce the methodology. The commercially available FE software COMSOL is used for implementing and coupling a physics-based dynamic model of the DEA with the external structure, i.e., the switch. The model is then experimentally calibrated and validated in both quasi-static and dynamic loading conditions. Finally, preliminary results on how to use the simulation tool to optimize the design are presented.

  1. Analogies between the Torque-Free Motion of a Rigid Body about a Fixed Point and Light Propagation in Anisotropic Media

    Science.gov (United States)

    Bellver-Cebreros, Consuelo; Rodriguez-Danta, Marcelo

    2009-01-01

    An apparently unnoticed analogy between the torque-free motion of a rotating rigid body about a fixed point and the propagation of light in anisotropic media is stated. First, a new plane construction for visualizing this torque-free motion is proposed. This method uses an intrinsic representation alternative to angular momentum and independent of…

  2. Simulation of the steady-state energy transfer in rigid bodies, with convective-radiative boundary conditions, employing a minimum principle

    International Nuclear Information System (INIS)

    Gama, R.M.S. da.

    1992-08-01

    The energy transfer phenomenon in a rigid and opaque body that exchanges energy, with the environment, by convection and by diffuse thermal radiation is studied. The considered phenomenon is described by a partial differential equation, subjected to (nonlinear) boundary conditions. A minimum principle, suitable for a large class of energy transfer problems is presented. Some particular cases are simulated. (author)

  3. A heterogeneous system based on GPU and multi-core CPU for real-time fluid and rigid body simulation

    Science.gov (United States)

    da Silva Junior, José Ricardo; Gonzalez Clua, Esteban W.; Montenegro, Anselmo; Lage, Marcos; Dreux, Marcelo de Andrade; Joselli, Mark; Pagliosa, Paulo A.; Kuryla, Christine Lucille

    2012-03-01

    Computational fluid dynamics in simulation has become an important field not only for physics and engineering areas but also for simulation, computer graphics, virtual reality and even video game development. Many efficient models have been developed over the years, but when many contact interactions must be processed, most models present difficulties or cannot achieve real-time results when executed. The advent of parallel computing has enabled the development of many strategies for accelerating the simulations. Our work proposes a new system which uses some successful algorithms already proposed, as well as a data structure organisation based on a heterogeneous architecture using CPUs and GPUs, in order to process the simulation of the interaction of fluids and rigid bodies. This successfully results in a two-way interaction between them and their surrounding objects. As far as we know, this is the first work that presents a computational collaborative environment which makes use of two different paradigms of hardware architecture for this specific kind of problem. Since our method achieves real-time results, it is suitable for virtual reality, simulation and video game fluid simulation problems.

  4. Modeling the exergy behavior of human body

    International Nuclear Information System (INIS)

    Keutenedjian Mady, Carlos Eduardo; Silva Ferreira, Maurício; Itizo Yanagihara, Jurandir; Hilário Nascimento Saldiva, Paulo; Oliveira Junior, Silvio de

    2012-01-01

    Exergy analysis is applied to assess the energy conversion processes that take place in the human body, aiming at developing indicators of health and performance based on the concepts of exergy destroyed rate and exergy efficiency. The thermal behavior of the human body is simulated by a model composed of 15 cylinders with elliptical cross section representing: head, neck, trunk, arms, forearms, hands, thighs, legs, and feet. For each, a combination of tissues is considered. The energy equation is solved for each cylinder, being possible to obtain transitory response from the body due to a variation in environmental conditions. With this model, it is possible to obtain heat and mass flow rates to the environment due to radiation, convection, evaporation and respiration. The exergy balances provide the exergy variation due to heat and mass exchange over the body, and the exergy variation over time for each compartments tissue and blood, the sum of which leads to the total variation of the body. Results indicate that exergy destroyed and exergy efficiency decrease over lifespan and the human body is more efficient and destroys less exergy in lower relative humidities and higher temperatures. -- Highlights: ► In this article it is indicated an overview of the human thermal model. ► It is performed the energy and exergy analysis of the human body. ► Exergy destruction and exergy efficiency decreases with lifespan. ► Exergy destruction and exergy efficiency are a function of environmental conditions.

  5. Rigid Bodies in Contact

    DEFF Research Database (Denmark)

    Niebe, Sarah Maria

    . A contact point determination method, based on boolean surface maps, is developed to handle collisions between tetrahedral meshes. The novel nonsmooth nonlinear conjugate gradient (NNCG) method is presented. The NNCG method is comparable in terms of accuracy to the state-of-the-art method, projected Gauss...

  6. Increased Exposure to Rigid Routines Can Lead to Increased Challenging Behavior Following Changes to Those Routines

    Science.gov (United States)

    Bull, Leah E.; Oliver, Chris; Callaghan, Eleanor; Woodcock, Kate A.

    2015-01-01

    Several neurodevelopmental disorders are associated with preference for routine and challenging behavior following changes to routines. We examine individuals with Prader-Willi syndrome, who show elevated levels of this behavior, to better understand how previous experience of a routine can affect challenging behavior elicited by disruption to…

  7. Increased rigidity with age in social behavior of Java-monkeys (Macaca fascicularis)

    NARCIS (Netherlands)

    Veenema, H.C.; Hooff, van J.A.R.A.M.; Gispen, W.H.; Spruijt, B.M.

    2001-01-01

    In this study we investigated the effect of aging on the structure of behavior of socially housed Java-monkeys. Indices of the sequential structure of an animal's own ongoing behavior and of its responses to behavior of other animals were calculated using an information statistic approach. These

  8. A topological classification of the Chaplygin systems in the dynamics of a rigid body in a fluid

    International Nuclear Information System (INIS)

    Nikolaenko, S S

    2014-01-01

    The paper is concerned with the topological analysis of the Chaplygin integrable case in the dynamics of a rigid body in a fluid. A full list of the topological types of Chaplygin systems in their dependence on the energy level is compiled on the basis of the Fomenko-Zieschang theory. An effective description of the topology of the Liouville foliation in terms of natural coordinate variables is also presented, which opens a direct way to calculating topological invariants. It turns out that on all nonsingular energy levels Chaplygin systems are Liouville equivalent to the well-known Euler case in the dynamics of a rigid body with fixed point. Bibliography: 23 titles

  9. On the existence of global strong solutions to the equations modeling a motion of a rigid body around a viscous fluid

    Czech Academy of Sciences Publication Activity Database

    Nečasová, Šárka; Wolf, J.

    2016-01-01

    Roč. 36, č. 3 (2016), s. 1539-1562 ISSN 1078-0947 R&D Projects: GA ČR GA13-00522S Institutional support: RVO:67985840 Keywords : incompressible fluid * motion of rigid body * strong solutions Subject RIV: BA - General Mathematics Impact factor: 1.099, year: 2016 http://www.aimsciences.org/journals/displayArticlesnew.jsp?paperID=11589

  10. A review of a method for dynamic load distribution, dynamical modeling, and explicit internal force control when two manipulators mutually lift and transport a rigid body object

    International Nuclear Information System (INIS)

    Unseren, M.A.

    1997-01-01

    The paper reviews a method for modeling and controlling two serial link manipulators which mutually lift and transport a rigid body object in a three dimensional workspace. A new vector variable is introduced which parameterizes the internal contact force controlled degrees of freedom. A technique for dynamically distributing the payload between the manipulators is suggested which yields a family of solutions for the contact forces and torques the manipulators impart to the object. A set of rigid body kinematic constraints which restrict the values of the joint velocities of both manipulators is derived. A rigid body dynamical model for the closed chain system is first developed in the joint space. The model is obtained by generalizing the previous methods for deriving the model. The joint velocity and acceleration variables in the model are expressed in terms of independent pseudovariables. The pseudospace model is transformed to obtain reduced order equations of motion and a separate set of equations governing the internal components of the contact forces and torques. A theoretic control architecture is suggested which explicitly decouples the two sets of equations comprising the model. The controller enables the designer to develop independent, non-interacting control laws for the position control and internal force control of the system

  11. A review of a method for dynamic load distribution, dynamical modeling, and explicit internal force control when two manipulators mutually lift and transport a rigid body object

    Energy Technology Data Exchange (ETDEWEB)

    Unseren, M.A.

    1997-04-20

    The paper reviews a method for modeling and controlling two serial link manipulators which mutually lift and transport a rigid body object in a three dimensional workspace. A new vector variable is introduced which parameterizes the internal contact force controlled degrees of freedom. A technique for dynamically distributing the payload between the manipulators is suggested which yields a family of solutions for the contact forces and torques the manipulators impart to the object. A set of rigid body kinematic constraints which restrict the values of the joint velocities of both manipulators is derived. A rigid body dynamical model for the closed chain system is first developed in the joint space. The model is obtained by generalizing the previous methods for deriving the model. The joint velocity and acceleration variables in the model are expressed in terms of independent pseudovariables. The pseudospace model is transformed to obtain reduced order equations of motion and a separate set of equations governing the internal components of the contact forces and torques. A theoretic control architecture is suggested which explicitly decouples the two sets of equations comprising the model. The controller enables the designer to develop independent, non-interacting control laws for the position control and internal force control of the system.

  12. Surface tension effects on the behavior of a cavity growing, collapsing, and rebounding near a rigid wall.

    Science.gov (United States)

    Zhang, Zhen-yu; Zhang, Hui-sheng

    2004-11-01

    Surface tension effects on the behavior of a pure vapor cavity or a cavity containing some noncondensible contents, which is growing, collapsing, and rebounding axisymmetrically near a rigid wall, are investigated numerically by the boundary integral method for different values of dimensionless stand-off parameter gamma, buoyancy parameter delta, and surface tension parameter beta. It is found that at the late stage of the collapse, if the resultant action of the Bjerknes force and the buoyancy force is not small, surface tension will not have significant effects on bubble behavior except that the bubble collapse time is shortened and the liquid jet becomes wider. If the resultant action of the two force is small enough, surface tension will have significant and in some cases substantial effects on bubble behavior, such as changing the direction of the liquid jet, making a new liquid jet appear, in some cases preventing the bubble from rebound before jet impact, and in other cases causing the bubble to rebound or even recollapse before jet impact. The mechanism of surface tension effects on the collapsing behavior of a cavity has been analyzed. The mechanisms of some complicated phenomena induced by surface tension effects are illustrated by analysis of the computed velocity fields and pressure contours of the liquid flow outside the bubble at different stages of the bubble evolution.

  13. Homogenized rigid body and spring-mass (HRBSM) model for the pushover analysis of out-of-plane loaded unreinforced and FRP reinforced walls

    Science.gov (United States)

    Bertolesi, Elisa; Milani, Gabriele

    2017-07-01

    The present paper is devoted to the discussion of a series of unreinforced and FRP retrofitted panels analyzed adopting the Rigid Body and Spring-Mass (HRBSM) model developed by the authors. To this scope, a total of four out of plane loaded masonry walls tested up to failure are considered. At a structural level, the non-linear analyses are conducted replacing the homogenized orthotropic continuum with a rigid element and non-linear spring assemblage by means of which out of plane mechanisms are allowed. FRP retrofitting is modeled adopting two noded truss elements whose mechanical properties are selected in order to describe possible debonding phenomenon or tensile rupture of the strengthening. The outcome provided numerically are compared to the experimental results showing a satisfactory agreement in terms of global pressure-deflection curves and failure mechanisms.

  14. Influence of Peripheral and Motivational Cues on Rigid-Flexible Functioning: Perceptual, Behavioral, and Cognitive Aspects

    Science.gov (United States)

    Cretenet, Joel; Dru, Vincent

    2009-01-01

    Recent research has shown that performing approach versus avoidance behaviors (arm flexion vs. extension) effectively influences cognitive functioning. In another area, lateralized peripheral activations (left vs. right side) of the motivational systems of approach versus avoidance were linked to various performances in cognitive tasks. By…

  15. A new method using insert-based systems (IBS) to improve cell behavior study on flexible and rigid biomaterials.

    Science.gov (United States)

    Grenade, Charlotte; Moniotte, Nicolas; Rompen, Eric; Vanheusden, Alain; Mainjot, Amélie; De Pauw-Gillet, Marie-Claire

    2016-12-01

    In vitro studies about biomaterials biological properties are essential screening tests. Yet cell cultures encounter difficulties related to cell retention on material surface or to the observation of both faces of permeable materials. The objective of the present study was to develop a reliable in vitro method to study cell behavior on rigid and flexible/permeable biomaterials elaborating two specific insert-based systems (IBS-R and IBS-F respectively). IBS-R was designed as a specific cylindrical polytetrafluoroethylene (PTFE) system to evaluate attachment, proliferation and morphology of human gingival fibroblasts (HGFs) on grade V titanium and lithium disilicate glass-ceramic discs characteristics of dental prostheses. The number of cells, their covering on discs and their morphology were determined from MTS assays and microscopic fluorescent images after 24, 48 and 72 h. IBS-F was developed as a two components system to study HGFs behavior on guided bone regeneration polyester membranes. The viability and the membrane barrier effect were evaluated by metabolic MTS assays and by scanning electron microscopy. IBS-R and IBS-F were shown to promote (1) easy and rapid handling; (2) cell retention on biomaterial surface; (3) accurate evaluation of the cellular proliferation, spreading and viability; (4) use of non-toxic material. Moreover IBS-F allowed the study of the cell migration through degradable membranes, with an access to both faces of the biomaterial and to the bottom of culture wells for medium changing.

  16. An Explicit Formulation of Singularity-Free Dynamic Equations of Mechanical Systems in Lagrangian Form---Part one: Single Rigid Bodies

    Directory of Open Access Journals (Sweden)

    Pål Johan From

    2012-04-01

    Full Text Available This paper presents the explicit dynamic equations of a mechanical system. The equations are presented so that they can easily be implemented in a simulation software or controller environment and are also well suited for system and controller analysis. The dynamics of a general mechanical system consisting of one or more rigid bodies can be derived from the Lagrangian. We can then use several well known properties of Lie groups to guarantee that these equations are well defined. This will, however, often lead to rather abstract formulation of the dynamic equations that cannot be implemented in a simulation software directly. In this paper we close this gap and show what the explicit dynamic equations look like. These equations can then be implemented directly in a simulation software and no background knowledge on Lie theory and differential geometry on the practitioner's side is required. This is the first of two papers on this topic. In this paper we derive the dynamics for single rigid bodies, while in the second part we study multibody systems. In addition to making the equations more accessible to practitioners, a motivation behind the papers is to correct a few errors commonly found in literature. For the first time, we show the detailed derivations and how to arrive at the correct set of equations. We also show through some simple examples that these correspond with the classical formulations found from Lagrange's equations. The dynamics is derived from the Boltzmann--Hamel equations of motion in terms of local position and velocity variables and the mapping to the corresponding quasi-velocities. Finally we present a new theorem which states that the Boltzmann--Hamel formulation of the dynamics is valid for all transformations with a Lie group topology. This has previously only been indicated through examples, but here we also present the formal proof. The main motivation of these papers is to allow practitioners not familiar with

  17. Anomalous behavior of cutoff rigidity variation in the region of the Mexico station during a magnetic superstorm on 20 November 2003

    Directory of Open Access Journals (Sweden)

    V. V. Pchelkin

    2007-08-01

    Full Text Available The pioneering storm-time model of magnetospheric magnetic field T01S made possible trajectory calculations for the events of giant magnetic storms. We have performed such calculations for a unique magnetic storm on 20 November 2003. In our previous paper, Belov et al. (2005, dedicated to the magnetospheric effects of cosmic rays (CR during this storm, we revealed an anomalous behavior of a cutoff rigidity variation at the Mexico station. Here, by trajectory calculations, we demonstrate that this peculiarity persists in the latitudinal and longitudinal curves of cutoff rigidity (Rc for both quiet and storm-time conditions and thus should be considered as physically meaningful.

  18. Sliding contact on the interface of elastic body and rigid surface using a single block Burridge-Knopoff model

    Science.gov (United States)

    Amireghbali, A.; Coker, D.

    2018-01-01

    Burridge and Knopoff proposed a mass-spring model to explore interface dynamics along a fault during an earthquake. The Burridge and Knopoff (BK) model is composed of a series of blocks of equal mass connected to each other by springs of same stiffness. The blocks also are attached to a rigid driver via another set of springs that pulls them at a constant velocity against a rigid substrate. They studied dynamics of interface for an especial case with ten blocks and a specific set of fault properties. In our study effects of Coulomb and rate-state dependent friction laws on the dynamics of a single block BK model is investigated. The model dynamics is formulated as a system of coupled nonlinear ordinary differential equations in state-space form which lends itself to numerical integration methods, e.g. Runge-Kutta procedure for solution. The results show that the rate and state dependent friction law has the potential of triggering dynamic patterns that are different from those under Coulomb law.

  19. A 3D, fully Eulerian, VOF-based solver to study the interaction between two fluids and moving rigid bodies using the fictitious domain method

    Science.gov (United States)

    Pathak, Ashish; Raessi, Mehdi

    2016-04-01

    We present a three-dimensional (3D) and fully Eulerian approach to capturing the interaction between two fluids and moving rigid structures by using the fictitious domain and volume-of-fluid (VOF) methods. The solid bodies can have arbitrarily complex geometry and can pierce the fluid-fluid interface, forming contact lines. The three-phase interfaces are resolved and reconstructed by using a VOF-based methodology. Then, a consistent scheme is employed for transporting mass and momentum, allowing for simulations of three-phase flows of large density ratios. The Eulerian approach significantly simplifies numerical resolution of the kinematics of rigid bodies of complex geometry and with six degrees of freedom. The fluid-structure interaction (FSI) is computed using the fictitious domain method. The methodology was developed in a message passing interface (MPI) parallel framework accelerated with graphics processing units (GPUs). The computationally intensive solution of the pressure Poisson equation is ported to GPUs, while the remaining calculations are performed on CPUs. The performance and accuracy of the methodology are assessed using an array of test cases, focusing individually on the flow solver and the FSI in surface-piercing configurations. Finally, an application of the proposed methodology in simulations of the ocean wave energy converters is presented.

  20. Adolescent Attitudes Toward Body Image and Anorexic Behavior.

    Science.gov (United States)

    Grant, Carol Lee; Fodor, Iris Goldstein

    1986-01-01

    Explored the relationship between anorexic behavior and selected dimensions of body image predictor variables, selected dimensions of body image, physical attractiveness, self-esteem, and physical effectiveness). Results indicated that the dimension of self-esteem was the major factor in the prediction of anorexic behaviors as measured by the…

  1. Cognitive-Behavioral Treatment of Women's Body-Image Dissatisfaction.

    Science.gov (United States)

    Butters, Jonathan W.; Cash, Thomas F.

    1987-01-01

    Assigned college women with a significant level of body-image dissatisfaction to a cognitive-behavioral treatment (CBT) program or to a waiting-list control group. The CBT program successfully improved affective body image, weakened maladaptive body-image cognitions, and enhanced social self-esteem and feelings about physical fitness and…

  2. Overestimation of body size in eating disorders and its association to body-related avoidance behavior.

    Science.gov (United States)

    Vossbeck-Elsebusch, Anna N; Waldorf, Manuel; Legenbauer, Tanja; Bauer, Anika; Cordes, Martin; Vocks, Silja

    2015-06-01

    Body-related avoidance behavior, e.g., not looking in the mirror, is a common feature of eating disorders. It is assumed that it leads to insufficient feedback concerning one's own real body form and might thus contribute to distorted mental representation of one's own body. However, this assumption still lacks empirical foundation. Therefore, the aim of the present study was to examine the relationship between misperception of one's own body and body-related avoidance behavior in N = 78 female patients with Bulimia nervosa and eating disorder not otherwise specified. Body-size misperception was assessed using a digital photo distortion technique based on an individual picture of each participant which was taken in a standardized suit. In a regression analysis with body-related avoidance behavior, body mass index and weight and shape concerns as predictors, only body-related avoidance behavior significantly contributed to the explanation of body-size overestimation. This result supports the theoretical assumption that body-related avoidance behavior makes body-size overestimation more likely.

  3. Disordered eating behaviors and body image in male athletes

    Directory of Open Access Journals (Sweden)

    Fernanda Reistenbach Goltz

    2013-09-01

    Full Text Available Objective: To identify disordered eating behaviors and body image dissatisfaction, as well as their relationship to body fat (BF, among male athletes in high risk sports for eating disorders. Methods: One hundred and fifty-six male athletes were divided into the following categories: weight-class sports, sports where leanness improves performance, and sports with aesthetic ideals. BF was assessed and three questionnaires were used: the Eating Attitudes Test; the Bulimic Investigatory Test, Edinburgh; the Body Shape Questionnaire. Results: Disordered eating behaviors and body image dissatisfaction were found in 43 (27.6% and 23 athletes (14.7%, respectively, and an association was detected between the two variables (p < 0.001. Athletes with and without disordered eating behaviors did not differ in %BF (11.0±5.2% and 9.8±4.0%, respectively; p = 0.106. However, athletes with body image dissatisfaction had higher %BF than those who were satisfied (12.6±5.9% and 9.7±3.9%, respectively; p = 0.034. There were no differences in BF, frequency of disordered eating behaviors, and body image dissatisfaction between sports categories. Conclusion: Nearly one-quarter of athletes showed disordered eating behaviors, which was associated with body image dissatisfaction. Athletes with higher %BF were more likely to be dissatisfied with body image. There was no difference in eating behavior and body image between athletes from different sports categories.

  4. Effects of nonlinearity in the materials used for the semi-rigid pedicle screw systems on biomechanical behaviors of the lumbar spine after surgery

    International Nuclear Information System (INIS)

    Kim, Hyun; Lee, Sung-Jae; Lim, Do-Hyung; Oh, Hyun-Ju; Lee, Kwon-Yong

    2011-01-01

    Recently, various types of semi-rigid pedicle screw fixation systems have been developed for the surgical treatment of the lumbar spine. They were introduced to address the adverse issues commonly found in traditional rigid spinal fusion--abnormally large motion at the adjacent level and subsequent degeneration. The semi-rigid system uses more compliant materials (nitinol or polymers) and/or changes in rod design (coiled or twisted rods) as compared to the conventional rigid straight rods made of Ti alloys (E = 114 GPa, υ = 0.32). However, biomechanical studies on the semi-rigid pedicle screw systems were usually limited to linear modeling of the implant and anatomic elements, which may not be capable of reflecting realistic post-operative motions of the spine. In this study, we evaluated the effects of nonlinearity in materials used for semi-rigid pedicle screw fixation systems to evaluate the changes in biomechanical behaviors using finite element analysis. Changes in range of motion (ROM) and center of rotation (COR) were assessed at the operated and adjacent levels. Actual load-displacement results of the semi-rigid rod from mechanical test were carried out to reflect the nonlinearity of the implant. In addition, nonlinear material properties of various spinal ligaments studies were used for the finite element modeling. The post-operative models were constructed by modifying the previously validated intact model of the L1-S1 spine. Eight different post-operative models were made to address the effects of nonlinearity-with a traditional stiffness modulus rod (with linear ligaments, case 1; with nonlinear ligaments, case 5), with a rigid rod (with linear ligaments, case 2; with nonlinear ligaments, case 6), with a soft rod (with linear ligaments, case 3; with nonlinear ligaments, case 7), and with a nonlinear rod (with linear ligaments, case 4; with nonlinear ligaments, case 8). To simulate the load on the lumbar spine in a neutral posture, follower load (400 N

  5. List-mode-based reconstruction for respiratory motion correction in PET using non-rigid body transformations

    International Nuclear Information System (INIS)

    Lamare, F; Carbayo, M J Ledesma; Cresson, T; Kontaxakis, G; Santos, A; Rest, C Cheze Le; Reader, A J; Visvikis, D

    2007-01-01

    Respiratory motion in emission tomography leads to reduced image quality. Developed correction methodology has been concentrating on the use of respiratory synchronized acquisitions leading to gated frames. Such frames, however, are of low signal-to-noise ratio as a result of containing reduced statistics. In this work, we describe the implementation of an elastic transformation within a list-mode-based reconstruction for the correction of respiratory motion over the thorax, allowing the use of all data available throughout a respiratory motion average acquisition. The developed algorithm was evaluated using datasets of the NCAT phantom generated at different points throughout the respiratory cycle. List-mode-data-based PET-simulated frames were subsequently produced by combining the NCAT datasets with Monte Carlo simulation. A non-rigid registration algorithm based on B-spline basis functions was employed to derive transformation parameters accounting for the respiratory motion using the NCAT dynamic CT images. The displacement matrices derived were subsequently applied during the image reconstruction of the original emission list mode data. Two different implementations for the incorporation of the elastic transformations within the one-pass list mode EM (OPL-EM) algorithm were developed and evaluated. The corrected images were compared with those produced using an affine transformation of list mode data prior to reconstruction, as well as with uncorrected respiratory motion average images. Results demonstrate that although both correction techniques considered lead to significant improvements in accounting for respiratory motion artefacts in the lung fields, the elastic-transformation-based correction leads to a more uniform improvement across the lungs for different lesion sizes and locations

  6. Explicit symplectic integrators of molecular dynamics algorithms for rigid-body molecules in the canonical, isobaric-isothermal, and related ensembles.

    Science.gov (United States)

    Okumura, Hisashi; Itoh, Satoru G; Okamoto, Yuko

    2007-02-28

    The authors propose explicit symplectic integrators of molecular dynamics (MD) algorithms for rigid-body molecules in the canonical and isobaric-isothermal ensembles. They also present a symplectic algorithm in the constant normal pressure and lateral surface area ensemble and that combined with the Parrinello-Rahman algorithm. Employing the symplectic integrators for MD algorithms, there is a conserved quantity which is close to Hamiltonian. Therefore, they can perform a MD simulation more stably than by conventional nonsymplectic algorithms. They applied this algorithm to a TIP3P pure water system at 300 K and compared the time evolution of the Hamiltonian with those by the nonsymplectic algorithms. They found that the Hamiltonian was conserved well by the symplectic algorithm even for a time step of 4 fs. This time step is longer than typical values of 0.5-2 fs which are used by the conventional nonsymplectic algorithms.

  7. Diagnostic-Photographic Determination of Drag/Lift/Torque Coefficients of High Speed Rigid Body in Water Column

    Science.gov (United States)

    2008-01-01

    various physical processes such as supercavitation and bubbles. A diagnostic- photographic method is developed in this study to determine the drag...nonlinear dynamics, body and multi-phase fluid interaction, supercavitation , and instability theory. The technical application of the hydrodynamics of...uV U ω= = − ×V e e e ei i , (29) where Eq.(9) is used. For a supercavitation area, a correction factor may be

  8. Effect of rigidity of porous structure on electrochemical behavior of pristine Li4Ti5O12 microspheres

    International Nuclear Information System (INIS)

    Jia, Zhenyong; Zhou, Qun; Li, Xiaowei; Fu, Yu; Ming, Hai; Zheng, Junwei

    2015-01-01

    Highlights: • Rigid porous framework of Li 4 Ti 5 O 12 microspheres can be fabricated by mutual molten growth of primary particles. • Well-confined nanosized tortuous channels are formed inside Li 4 Ti 5 O 12 microspheres. • Li 4 Ti 5 O 12 microspheres with rigid porous structures exhibit greatly enhanced electrochemical performance. - Abstract: Highly controllable porous architecture is desirable to tailor the physical and chemical properties of functional materials in advanced lithium ion batteries. Here, porous microspheres of spinel lithium titanate (Li 4 Ti 5 O 12 ), a promising alternative anode material for lithium ion batteries, are fabricated by mutual molten growth method in a controllable manner. The key role of the rigidity of the porous structure on the performance of the electrode materials in lithium ion batteries is demonstrated. Rigid framework of the materials is formed by second growth of the primary particles that fused together to generate an interconnected nanopore system inside the spheres, leading to better electrolyte diffusion and lower interparticle contact resistance, relative to the non-porous counterpart. The pristine Li 4 Ti 5 O 12 microspheres with uniform pore distribution and continuous framework exhibit high tap density, remarkable reversible capacity and rate capability, as well as excellent cycling stability. The present method is scalable and may provide a new approach to fabricate other candidate electrode materials for applications that require both high power and high volumetric energy density

  9. Adolescents Eating Behavior, Body Image and Psychological Well-Being

    OpenAIRE

    Peternel, Lana; Sujoldžić, Anita

    2009-01-01

    This study focuses on the middle school students in the Croatian region of Dalmatia. The survey was designed to examine adolescent eating behavior as it relates to body image and psychological well-being (self-esteem, life-satisfaction and stress) in relation to body mass index; BMI. Differences among participants in food intake were examined according to demographic variables and eating behavior (regular food intake or dieting) as well. Psychological variables were highly associated with die...

  10. Computation of LACBED images from bi-crystals using reciprocity. Part 1 Rigid-body displacements between parallel crystals

    International Nuclear Information System (INIS)

    Kube, D.; Goodman, P.; Forwood, C.; Rossouw, C.

    1997-01-01

    A new method for the rapid generation of high resolution bicrystal LACBED images is described, which uses reciprocity to generate the second-crystal transmission function for a specific doubly-transmitted beam. As a result, sets of bright-field or specific dark-field LACBED images can readily be generated for sets inter-crystal displacements, to allow comparison with experimental results. In Part I we describe results obtained for pure translations between bi-crystals pairs, while in Part II we describe the method for bi-crystals incorporating relative rotations as well as translations. It is envisaged that this technique will be useful for the body semi-conductor crystal pair interfaces, and metal-alloy grain boundaries, in particular. (authors). 16 refs., 6 figs

  11. A Cognitive-Behavioral Treatment Approach for Body Dysmorphic Disorder

    Science.gov (United States)

    Wilhelm, Sabine; Buhlmann, Ulrike; Hayward, Laura C.; Greenberg, Jennifer L.; Dimaite, Ruta

    2010-01-01

    Although body dysmorphic disorder (BDD) has been described in the literature for more than a century, there has been only a limited focus on the development of cognitive behavioral treatments for BDD. Our case report provides a detailed description of a course of cognitive behavioral treatment (CBT) for an individual with BDD. The patient was…

  12. Body-focused repetitive behavior disorders in ICD-11

    Directory of Open Access Journals (Sweden)

    Jon E. Grant

    2014-01-01

    Full Text Available This article addresses the question of how body-focused repetitive behavior disorders (e.g., trichotillomania and skin-picking disorder should be characterized in ICD-11. The article reviews the historical nosology of the two disorders and the current approaches in DSM-5 and ICD-10. Although data are limited and mixed regarding the optimal relationship between body-focused repetitive behavior disorders and nosological categories, these conditions should be included within the obsessive-compulsive and related disorders category, as this is how most clinicians see these behaviors, and as this may optimize clinical utility. The descriptions of these disorders should largely mirror those in DSM-5, given the evidence from recent field surveys. The recommendations regarding ICD-11 and body-focused repetitive behavior disorders should promote the global identification and treatment of these conditions in primary care settings.

  13. Fire Behavior of Rigid Polyurethane Foam and Metal Faced Polyurethane Sandwich Panels and Its Fire Hazard Assessment

    Directory of Open Access Journals (Sweden)

    S. Bakhtiyari

    2009-12-01

    Full Text Available Reaction to fire of fire-retarded rigid PUR foams and two types of metal faced rigid polyurethane foam core sandwich panel was evaluated by using cone calorimeter test method. The tests were carried out in various radiative heat fluxes from 15 to 75 kW/m2. The radiation rate effect on reaction to fire parameters, including time to ignition (TTI, peak of heat release rate (PRHR, total heat release (THR, average heat release rate (Av.RHR and average heat of combustion (Av.EHC was investigated. The phenomenon of char forming, when the foam is exposed to heat, leads to the formation of a protective layer on the surface of foam and hence no direct relation exists between Av.RHR and average specific mass loss rate (Av.Spec.MLR of foam with increased radiation rate. In addition, the increased PRHR with foam density was also very smooth. The relation between TTI and heat flux was investigated for the foam and its corresponding correlation has been achieved with a specified density. Fire hazard assessment of foams and sandwitch panels was carried out by adopting Petrella and Richardson fire risk classification methods. The assessment results showed that rigid PUR foam and PUR sandwich panels may have a high contribution to bring the room to critical flashover condition, but the risk is intermediate from the viewpoint of fire endurance. The reasons of these risk levels are attributed to a very short TTI, relative high PRHR and an intermediate amount of THR. Decrease in foam density reduces heat release but it shows no significant effect on reducing flashover hazard.

  14. Enstatite, Mg2Si2O6: A neutron diffraction refinement of the crystal structure and a rigid-body analysis of the thermal vibration

    International Nuclear Information System (INIS)

    Ghose, S.; Schomaker, V.; McMullan, R.K.

    1986-01-01

    Synthetic enstatite, Mg 2 Si 2 O 6 , is orthorhombic, space group Pbca, with eight formula units per cell and lattice parameters a = 18.235(3), b = 8.818(1), c = 5.179(1) A at 23 0 C. A least-squares structure refinement based on 1790 neutron intensity data converged with an agreement factor R(F 2 ) = 0.032, yielding Mg-O and Si-O bond lengths with standard deviations of 0.0007 and 0.0008 A, respectively. The variations observed in the Si-O bond lengths within the silicate tetrahedra A and B are caused by the differences in primary coordination of the oxygen atoms and the proximity of the magnesium ions to the silicon atoms. The latter effect is most pronounced for the bridging bonds of tetrahedron. A. The smallest O-Si-O angle is the result of edge-sharing by the Mg(2) octahedron and the A tetrahedron. An analysis of rigid-body thermal vibrations of the two crystallographically independent [SiO 4 ] tetrahedra indicates considerable librational motion, leading to a thermal correction of apparent Si-O bond lengths as large as +0.002 A at room temperature. (orig.)

  15. Behavior and Body Patterns of the Larger Pacific Striped Octopus.

    Directory of Open Access Journals (Sweden)

    Roy L Caldwell

    Full Text Available Over thirty years ago anecdotal accounts of the undescribed Larger Pacific Striped Octopus suggested behaviors previously unknown for octopuses. Beak-to-beak mating, dens shared by mating pairs, inking during mating and extended spawning were mentioned in publications, and enticed generations of cephalopod biologists. In 2012-2014 we were able to obtain several live specimens of this species, which remains without a formal description. All of the unique behaviors listed above were observed for animals in aquaria and are discussed here. We describe the behavior, body color patterns, and postures of 24 adults maintained in captivity. Chromatophore patterns of hatchlings are also shown.

  16. Behavior and Body Patterns of the Larger Pacific Striped Octopus.

    Science.gov (United States)

    Caldwell, Roy L; Ross, Richard; Rodaniche, Arcadio; Huffard, Christine L

    2015-01-01

    Over thirty years ago anecdotal accounts of the undescribed Larger Pacific Striped Octopus suggested behaviors previously unknown for octopuses. Beak-to-beak mating, dens shared by mating pairs, inking during mating and extended spawning were mentioned in publications, and enticed generations of cephalopod biologists. In 2012-2014 we were able to obtain several live specimens of this species, which remains without a formal description. All of the unique behaviors listed above were observed for animals in aquaria and are discussed here. We describe the behavior, body color patterns, and postures of 24 adults maintained in captivity. Chromatophore patterns of hatchlings are also shown.

  17. Using a novel rigid-fluoride polymer to control the interfacial thickness of graphene and tailor the dielectric behavior of poly(vinylidene fluoride-trifluoroethylene-chlorotrifluoroethylene) nanocomposites.

    Science.gov (United States)

    Han, Xianghui; Chen, Sheng; Lv, Xuguang; Luo, Hang; Zhang, Dou; Bowen, Chris R

    2018-01-24

    Polymer nanocomposites based on conductive fillers for high performance dielectrics have attracted increasing attention in recent years. However, a number of physical issues are unclear, such as the effect of interfacial thickness on the dielectric properties of the polymer nanocomposites, which limits the enhancement of permittivity. In this research, two core-shell structured reduced graphene oxide (rGO)@rigid-fluoro-polymer conducting fillers with different shell thicknesses are prepared using a surface-initiated reversible-addition-fragmentation chain transfer polymerization method, which are denoted as rGO@PTFMS-1 with a thin shell and rGO@PTFMS-2 with a thick shell. A rigid liquid crystalline fluoride-polymer poly{5-bis[(4-trifluoro-methoxyphenyl)oxycarbonyl]styrene} (PTFMS) is chosen for the first time to tailor the shell thicknesses of rGO via tailoring the degree of polymerization. The effect of interfacial thickness on the dielectric behavior of the P(VDF-TrFE-CTFE) nanocomposites with rGO and modified rGO is studied in detail. The results demonstrate that the percolation threshold of the nanocomposites increased from 0.68 vol% to 1.69 vol% with an increase in shell thickness. Compared to the rGO@PTFMS-1/P(VDF-TrFE-CTFE) composites, the rGO@PTFMS-2/P(VDF-TrFE-CTFE) composites exhibited a higher breakdown strength and a lower dielectric constant, which can be interpreted by interfacial polarization and the micro-capacitor model, resulting from the insulating nature of the rigid-polymer shell and the change of rGO's morphology. The findings provide an innovative approach to tailor dielectric composites, and promote a deeper understanding of the influence of interfacial region thickness on the dielectric performance.

  18. Cognitive-Behavioral Therapy for Adolescent Body Dysmorphic Disorder

    Science.gov (United States)

    Greenberg, Jennifer L.; Markowitz, Sarah; Petronko, Michael R.; Taylor, Caitlin E.; Wilhelm, Sabine; Wilson, G. Terence

    2010-01-01

    The onset of appearance-related concerns associated with body dysmorphic disorder (BDD) typically occurs in adolescence, and these concerns are often severe enough to interfere with normal development and psychosocial functioning. Cognitive behavioral therapy (CBT) is an effective treatment for adults with BDD. However, no treatment studies…

  19. Modular Cognitive-Behavioral Therapy for Body Dysmorphic Disorder

    Science.gov (United States)

    Wilhelm, Sabine; Phillips, Katharine A.; Fama, Jeanne M.; Greenberg, Jennifer L.; Steketee, Gail

    2011-01-01

    This study pilot tested a newly developed modular cognitive-behavioral therapy (CBT) treatment manual for body dysmorphic disorder (BDD). We tested feasibility, acceptability, and treatment outcome in a sample of 12 adults with primary BDD. Treatment was delivered in weekly individual sessions over 18 or 22 weeks. Standardized clinician ratings…

  20. FOOD BEHAVIOR, BODY IMAGE AND ANTHROPOMETRIC INDICES OF UNIVERSITY STUDENTS

    Directory of Open Access Journals (Sweden)

    Márcia Regina Pereira MONTEIRO

    2010-12-01

    Full Text Available

    The aim of this study was to assess food behavior, self-image perception and anthropometric indices of college students. This was a cross-sectional study with 54 students in a public university. The lifestyle and self-image perception was collected using a standardized questionnaire tested. Food behavior was evaluated through the Eating Attitudes Test. Body composition was assessed for Body Mass Index (BMI, circumferences, skinfold analysis and bioelectrical impedance (BIA. The statistics tests used were Chi-square and Pearson correlation (p< 0.05. The students had 19 to 27 years old, 96.3% were non-smokers, 46.3% drank alcoholic beverages and 37.0% practiced regular physical activity. Most of the students (75.5% were considered normal weight (BMI but the body fat percentage was found to be above average. Regarding self- image perception, 40.7% felt overweight. Observing food behavior results, 12.0% were at risk of developing eating disorders. Positive correlations were verifi ed between BMI with skinfold and skinfold with bioelectrical impedance. It was concluded that a considerable number of the college students assessed had a distorted self-image perception. Many of them had normal weight but with high body fat percentage. This study is relevant to investigate the risk of eating disorders and body image perception as part of the nutritional assessment.

  1. Structure of the N-terminal Gyrase B fragment in complex with ADP⋅Pi reveals rigid-body motion induced by ATP hydrolysis.

    Directory of Open Access Journals (Sweden)

    Frédéric V Stanger

    Full Text Available Type II DNA topoisomerases are essential enzymes that catalyze topological rearrangement of double-stranded DNA using the free energy generated by ATP hydrolysis. Bacterial DNA gyrase is a prototype of this family and is composed of two subunits (GyrA, GyrB that form a GyrA2GyrB2 heterotetramer. The N-terminal 43-kDa fragment of GyrB (GyrB43 from E. coli comprising the ATPase and the transducer domains has been studied extensively. The dimeric fragment is competent for ATP hydrolysis and its structure in complex with the substrate analog AMPPNP is known. Here, we have determined the remaining conformational states of the enzyme along the ATP hydrolysis reaction path by solving crystal structures of GyrB43 in complex with ADP⋅BeF3, ADP⋅Pi, and ADP. Upon hydrolysis, the enzyme undergoes an obligatory 12° domain rearrangement to accommodate the 1.5 Å increase in distance between the γ- and β-phosphate of the nucleotide within the sealed binding site at the domain interface. Conserved residues from the QTK loop of the transducer domain (also part of the domain interface couple the small structural change within the binding site with the rigid body motion. The domain reorientation is reflected in a significant 7 Å increase in the separation of the two transducer domains of the dimer that would embrace one of the DNA segments in full-length gyrase. The observed conformational change is likely to be relevant for the allosteric coordination of ATP hydrolysis with DNA binding, cleavage/re-ligation and/or strand passage.

  2. Effects of cognitive behavioral counseling on body Image following mastectomy.

    Science.gov (United States)

    Fadaei, Simin; Janighorban, Mojgan; Mehrabi, Tayebe; Ahmadi, Sayed Ahmadi; Mokaryan, Fariborz; Gukizade, Abbas

    2011-08-01

    Breast cancer is the most common cancer in women. Surgical treatment of breast cancer may cause body image alterations. The purpose of the current study was to examine the effects of cognitive behavioral counseling on body image among Iranian women with primary breast cancer. In this quasi-experimental designed study, 72 patients diagnosed as breast cancer and surgically treated were enrolled in Isfahan, Iran. The patients were entered the study by convenience sampling method and were randomly divided in two groups of intervention (n = 32) and control (n = 40). The intervention group received consultation based on Ellis rational emotive behavior therapy (REBT) method for 6 sessions during 3 weeks. The control group did not receive any consultation Paired t-test was used to compare the changes in groups and independent t-test was conducted to compare two groups. The average values represented as mean ± standard deviation. Before the study, the body image score was not significantly different between the intervention (16 97 ± 5 44) and control (15 95 ± 4 66) groups (t = 0 86, P = 0 395). The body image score was significantly lower in the interven-tion group (9 03 ± 6 11) compared to control group (17 18 ± 5 27) after the intervention (t = -6 07, P influences her breast cancer treatment decision, oncology professionals need to recognize the value of a woman's favorite about appearance and body image. This study emphasizes the importance of offering consultation in breast cancer patients.

  3. Effect of bending stiffness on the peeling behavior of an elastic thin film on a rigid substrate.

    Science.gov (United States)

    Peng, Zhilong; Chen, Shaohua

    2015-04-01

    Inspired by the experimental observation that the maximum peeling force of elastic films on rigid substrates does not always emerge at the steady-state peeling stage, but sometimes at the initial one, a theoretical model is established in this paper, in which not only the effect of the film's bending stiffness on the peeling force is considered, but also the whole peeling process, from the initiation of debonding to the steady-state stage, is characterized. Typical peeling force-displacement curves and deformed profiles of the film reappear for the whole peeling process. For the case of a film with relatively large bending stiffness, the maximum peeling force is found arising at the initial peeling stage and the larger the stiffness of the film, the larger the maximum peeling force is. With the peeling distance increasing, the peeling force is reduced from the maximum to a constant at the steady-state stage. For the case of a film with relatively small stiffness, the peeling force increases monotonically at the initial stage and then achieves a constant as the maximum at the steady-state stage. Furthermore, the peeling forces in the steady-state stage are compared with those of the classical Kendall model. All the theoretical predictions agree well with the existing experimental and numerical observations, from which the maximum peeling force can be predicted precisely no matter what the stiffness of the film is. The results in this paper should be very helpful in the design and assessment of the film-substrate interface.

  4. A review of a method for dynamic load distribution, dynamic modeling, and explicit internal force control when two serial link manipulators mutually lift and transport a rigid body object

    International Nuclear Information System (INIS)

    Unseren, M.A.

    1997-09-01

    The report reviews a method for modeling and controlling two serial link manipulators which mutually lift and transport a rigid body object in a three dimensional workspace. A new vector variable is introduced which parameterizes the internal contact force controlled degrees of freedom. A technique for dynamically distributing the payload between the manipulators is suggested which yields a family of solutions for the contact forces and torques the manipulators impart to the object. A set of rigid body kinematic constraints which restricts the values of the joint velocities of both manipulators is derived. A rigid body dynamical model for the closed chain system is first developed in the joint space. The model is obtained by generalizing the previous methods for deriving the model. The joint velocity and acceleration variables in the model are expressed in terms of independent pseudovariables. The pseudospace model is transformed to obtain reduced order equations of motion and a separate set of equations governing the internal components of the contact forces and torques. A theoretic control architecture is suggested which explicitly decouples the two sets of equations comprising the model. The controller enables the designer to develop independent, non-interacting control laws for the position control and internal force control of the system

  5. A review of a method for dynamic load distribution, dynamic modeling, and explicit internal force control when two serial link manipulators mutually lift and transport a rigid body object

    Energy Technology Data Exchange (ETDEWEB)

    Unseren, M.A.

    1997-09-01

    The report reviews a method for modeling and controlling two serial link manipulators which mutually lift and transport a rigid body object in a three dimensional workspace. A new vector variable is introduced which parameterizes the internal contact force controlled degrees of freedom. A technique for dynamically distributing the payload between the manipulators is suggested which yields a family of solutions for the contact forces and torques the manipulators impart to the object. A set of rigid body kinematic constraints which restricts the values of the joint velocities of both manipulators is derived. A rigid body dynamical model for the closed chain system is first developed in the joint space. The model is obtained by generalizing the previous methods for deriving the model. The joint velocity and acceleration variables in the model are expressed in terms of independent pseudovariables. The pseudospace model is transformed to obtain reduced order equations of motion and a separate set of equations governing the internal components of the contact forces and torques. A theoretic control architecture is suggested which explicitly decouples the two sets of equations comprising the model. The controller enables the designer to develop independent, non-interacting control laws for the position control and internal force control of the system.

  6. Developmental process emerges from extended brain-body-behavior networks

    Science.gov (United States)

    Byrge, Lisa; Sporns, Olaf; Smith, Linda B.

    2014-01-01

    Studies of brain connectivity have focused on two modes of networks: structural networks describing neuroanatomy and the intrinsic and evoked dependencies of functional networks at rest and during tasks. Each mode constrains and shapes the other across multiple time scales, and each also shows age-related changes. Here we argue that understanding how brains change across development requires understanding the interplay between behavior and brain networks: changing bodies and activities modify the statistics of inputs to the brain; these changing inputs mold brain networks; these networks, in turn, promote further change in behavior and input. PMID:24862251

  7. Effects of cognitive behavioral counseling on body Image following mastectomy

    Directory of Open Access Journals (Sweden)

    Simin Fadaei

    2011-01-01

    Full Text Available Background: Breast cancer is the most common cancer in women. Surgical treatment of breast cancer may cause body image alterations. The purpose of the current study was to examine the effects of cognitive behavioral counseling on body image among Iranian women with primary breast cancer. Methods: In this quasi-experimental designed study, 72 patients diagnosed as breast cancer and surgically treated were enrolled in Isfahan, Iran. The patients were entered the study by convenience sampling method and were randomly di-vided in two groups of intervention (n = 32 and control (n = 40. The intervention group received consultation based on Ellis rational emotive behavior therapy (REBT method for 6 sessions during 3 weeks. The control group did not re-ceive any consultation Paired t-test was used to compare the changes in groups and independent t-test was conducted to compare two groups. The average values represented as mean ± standard deviation. Results: Before the study, the body image score was not significantly different between the intervention (16 97 ± 5 44 and control (15 95 ± 4 66 groups (t = 0 86, P = 0 395. The body image score was significantly lower in the interven-tion group (9 03 ± 6 11 compared to control group (17 18 ± 5 27 after the intervention (t = -6 07, P < 0 001. Conclusions: Since a woman′s body image influences her breast cancer treatment decision, oncology professionals need to recognize the value of a woman′s favorite about appearance and body image. This study emphasizes the impor-tance of offering consultation in breast cancer patients.

  8. Body odor quality predicts behavioral attractiveness in humans.

    Science.gov (United States)

    Roberts, S Craig; Kralevich, Alexandra; Ferdenzi, Camille; Saxton, Tamsin K; Jones, Benedict C; DeBruine, Lisa M; Little, Anthony C; Havlicek, Jan

    2011-12-01

    Growing effort is being made to understand how different attractive physical traits co-vary within individuals, partly because this might indicate an underlying index of genetic quality. In humans, attention has focused on potential markers of quality such as facial attractiveness, axillary odor quality, the second-to-fourth digit (2D:4D) ratio and body mass index (BMI). Here we extend this approach to include visually-assessed kinesic cues (nonverbal behavior linked to movement) which are statistically independent of structural physical traits. The utility of such kinesic cues in mate assessment is controversial, particularly during everyday conversational contexts, as they could be unreliable and susceptible to deception. However, we show here that the attractiveness of nonverbal behavior, in 20 male participants, is predicted by perceived quality of their axillary body odor. This finding indicates covariation between two desirable traits in different sensory modalities. Depending on two different rating contexts (either a simple attractiveness rating or a rating for long-term partners by 10 female raters not using hormonal contraception), we also found significant relationships between perceived attractiveness of nonverbal behavior and BMI, and between axillary odor ratings and 2D:4D ratio. Axillary odor pleasantness was the single attribute that consistently predicted attractiveness of nonverbal behavior. Our results demonstrate that nonverbal kinesic cues could reliably reveal mate quality, at least in males, and could corroborate and contribute to mate assessment based on other physical traits.

  9. Extracellular matrix composition and rigidity regulate invasive behavior and response to PDT in 3D pancreatic tumor models

    Science.gov (United States)

    Cramer, Gwendolyn; El-Hamidi, Hamid; Jafari, Seyedehrojin; Jones, Dustin P.; Celli, Jonathan P.

    2016-03-01

    The composition and mechanical compliance of the extracellular matrix (ECM) have been shown to serve as regulators of tumor growth and invasive behavior. These effects may be particularly relevant in tumors of the pancreas, noted for a profound desmoplastic reaction and an abundance of stroma rich in ECM. In view of recent progress in the clinical implementation of photodynamic therapy (PDT) for pancreatic tumors, in this report we examine how ECM composition and rheological properties impact upon invasive behavior and response to PDT in 3D multicellular pancreatic tumor spheroids in ECM environments with characterized rheological properties. Tumor spheroids were cultured initially in attachment-free conditions to form millimeter-sized spheroids that were transplanted into reconstituted ECM microenvironments (Matrigel and Type I Collagen) that were characterized using bulk oscillatory shear rheology. Analysis of growth behavior shows that the soft collagen ECM promoted growth and extensive invasion and this microenvironment was used in subsequent assessment of PDT and chemotherapy response. Evaluation of treatment response revealed that primary tumor nodule growth is inhibited more effectively with PDT, while verteporfin PDT response is significantly enhanced in the ECM-infiltrating populations that are non-responsive to oxaliplatin chemotherapy. This finding is potentially significant, suggesting the potential for PDT to target these clinically problematic invasive populations that are associated with aggressive metastatic progression and chemoresistance. Experiments to further validate and identify the mechanistic basis of this observation are ongoing.

  10. Rigidity of Glasses and Macromolecules

    Science.gov (United States)

    Thorpe, M. F.

    1998-03-01

    The simple yet powerful ideas of percolation theory have found their way into many different areas of research. In this talk we show how RIGIDITY PERCOLATION can be studied at a similar level of sophistication, using a powerful new program THE PEBBLE GAME (D. J. Jacobs and M. F. Thorpe, Phys. Rev. E) 53, 3682 (1996). that uses an integer algorithm. This program can analyse the rigidity of two and three dimensional networks containing more than one million bars and joints. We find the total number of floppy modes, and find the critical behavior as the network goes from floppy to rigid as more bars are added. We discuss the relevance of this work to network glasses, and how it relates to experiments that involve the mechanical properties like hardness and elasticity of covalent glassy networks like Ge_xAs_ySe_1-x-y and dicuss recent experiments that suggest that the rigidity transition may be first order (Xingwei Feng, W. J.Bresser and P. Boolchand, Phys. Rev. Lett 78), 4422 (1997).. This approach is also useful in macromolecules and proteins, where detailed information about the rigid domain structure can be obtained.

  11. Human body scents: do they influence our behavior?

    Science.gov (United States)

    Mildner, Sophie; Buchbauer, Gerhard

    2013-11-01

    Pheromonal communication in the animal world has been of great research interest for a long time. While extraordinary discoveries in this field have been made, the importance of the human sense of smell was of far lower interest. Humans are seen as poor smellers and therefore research about human olfaction remains quite sparse compared with other animals. Nevertheless amazing achievements have been made during the past 15 years. This is a collection of available data on this topic and a controversial discussion on the role of putative human pheromones in our modem way of living. While the focus was definitely put on behavioral changes evoked by putative human pheromones this article also includes other important aspects such as the possible existence of a human vomeronasal organ. If pheromones do have an influence on human behavior there has to be a receptor organ. How are human body scents secreted and turned into odorous substances? And how can con-specifics detect those very odors and transmit them to the brain? Apart from that the most likely candidates for human pheromones are taken on account and their impact on human behavior is shown in various detail.

  12. Associative memory through rigid origami

    Science.gov (United States)

    Murugan, Arvind; Brenner, Michael

    2015-03-01

    Mechanisms such as Miura Ori have proven useful in diverse contexts since they have only one degree of freedom that is easily controlled. We combine the theory of rigid origami and associative memory in frustrated neural networks to create structures that can ``learn'' multiple generic folding mechanisms and yet can be robustly controlled. We show that such rigid origami structures can ``recall'' a specific learned mechanism when induced by a physical impulse that only need resemble the desired mechanism (i.e. robust recall through association). Such associative memory in matter, seen before in self-assembly, arises due to a balance between local promiscuity (i.e., many local degrees of freedom) and global frustration which minimizes interference between different learned behaviors. Origami with associative memory can lead to a new class of deployable structures and kinetic architectures with multiple context-dependent behaviors.

  13. Comportement comparé de conduites rigides et flexibles ensouillées au voisinage de sols gelés Comparative Behavior of Rigid and Flexible Pipes Buried in the Vicinity of Frozen Ground

    Directory of Open Access Journals (Sweden)

    Putot C.

    2006-11-01

    Full Text Available Au cours des dernières années, les activités pétrolières à terre comme en mer, tant en Alaska qu'au Canada, se sont maintenues à un niveau raisonnable. En octobre 1987, le premier champ pétrolier offshore a été mis en exploitation en mer de Beaufort (Endicott. Bien que l'industrie soit principalement dans une phase d'exploration, des besoins vont progressivement se manifester en matière de lignes de collecte et d'injection. La détermination du tracé de conduites en offshore arctique ainsi que leur dimensionnement nécessite la prise en compte de facteurs très spécifiques : le raclage des glaces dérivantes impose une profondeur minimum d'ensouillage, ce qui accroît, malgré l'isolation des conduites, la proportion de chaleur communiquée au pergélisol (ou permafrost en dégel : les tassements différentiels résultant de la variabilité de composition des sols peuvent provoquer des déformations, voire des instabilités des conduites tout à fait inacceptables. Il est assez intuitif de penser que les conduites flexibles accommoderont plus facilement les mouvements de sol que les rigides. L'objet de cet article est de proposer une méthode d'analyse assez souple permettant de jauger facilement cet avantage. In recent years, onshore and offshore petroleum activities, in both Alaska and Canada, have continued on a reasonable level. In October 1987 the first offshore oil field began production in the Beaufort Sea (Endicott. Although the industry is mainly in an exploration phase, needs will steadily appear with regard to gathering and injection line. . The determination to lay flowlines in offshore arctic areas as well as their sizing require that very specific factors be taken into consideration. Scouring by drifting ice requires a minimum depth of burial. Despite the insulation of pipes, this burial increases the proportion of heat communicated to melting permafrost. The differential compaction resulting from the variability of

  14. Emotional reactions following exposure to idealized bodies predict unhealthy body change attitudes and behaviors in women and men.

    Science.gov (United States)

    Cahill, Sara; Mussap, Alexander J

    2007-06-01

    We explored the extent to which changes in emotional states following exposure to images of idealized bodies predict unhealthy body change attitudes and behaviors in women and men, and whether particular psychological traits mediate these effects. One hundred thirty-three women and 93 men were assessed for unhealthy attitudes and behaviors related to body weight and muscles using the Eating Disorder Inventory-2 (EDI-2), the Obligatory Exercise Questionnaire, and the strategies to increase muscles subscale of the Body Change Inventory. Psychological traits assessed included body dissatisfaction (EDI-2), internalization of the thin/athletic ideal (Sociocultural Attitudes Towards Appearance Questionnaire-3), body comparison (Body Comparison Scale), self-esteem (Rosenberg Self-Esteem Inventory), depression (Beck Depression Inventory-II), and identity confusion (Self-Concept Clarity Scale). Participants were then exposed to photographs of thin female models and muscular male models, and visual analogue scales were used to measure changes in postexposure state body dissatisfaction, anger, anxiety, and depression. Postexposure increases in state anger, anxiety, depression, and body dissatisfaction correlated with drive for thinness and disordered eating symptomatology in women, while postexposure increases in state body dissatisfaction correlated with muscle development in men. Analyses revealed that internalization and body comparison mediated these relationships, with trait body dissatisfaction, trait depression, self-esteem, and self-concept/identity confusion serving as mediators for women only. These results are indicative of gender differences in: (a) reactions to idealized bodies; (b) psychological traits that predispose individuals to experience these reactions; and (c) types of body change behavior that are associated with these reactions.

  15. Animal behavior frozen in time: gregarious behavior of Early Jurassic lobsters within an ammonoid body chamber.

    Science.gov (United States)

    Klompmaker, Adiël A; Fraaije, René H B

    2012-01-01

    Direct animal behavior can be inferred from the fossil record only in exceptional circumstances. The exceptional mode of preservation of ammonoid shells in the Posidonia Shale (Lower Jurassic, lower Toarcian) of Dotternhausen in southern Germany, with only the organic periostracum preserved, provides an excellent opportunity to observe the contents of the ammonoid body chamber because this periostracum is translucent. Here, we report upon three delicate lobsters preserved within a compressed ammonoid specimen of Harpoceras falciferum. We attempt to explain this gregarious behavior. The three lobsters were studied using standard microscopy under low angle light. The lobsters belong to the extinct family of the Eryonidae; further identification was not possible. The organic material of the three small lobsters is preserved more than halfway into the ammonoid body chamber. The lobsters are closely spaced and are positioned with their tails oriented toward each other. The specimens are interpreted to represent corpses rather than molts. The lobsters probably sought shelter in preparation for molting or against predators such as fish that were present in Dotternhausen. Alternatively, the soft tissue of the ammonoid may have been a source of food that attracted the lobsters, or it may have served as a long-term residency for the lobsters (inquilinism). The lobsters represent the oldest known example of gregariousness amongst lobsters and decapods in the fossil record. Gregarious behavior in lobsters, also known for extant lobsters, thus developed earlier in earth's history than previously known. Moreover, this is one of the oldest known examples of decapod crustaceans preserved within cephalopod shells.

  16. Sensorimotor body-environment interaction serves to regulate emotional experience and exploratory behavior

    Directory of Open Access Journals (Sweden)

    Martin Dobricki

    2016-10-01

    Full Text Available Almost all living species regularly explore environments that they experience as pleasant, aversive, arousing or frightening. We postulate that such exploratory behavior and emotional experience both are regulated based on the interdependent perception of one’s body and stimuli that collectively define a spatial context such as a cliff. Here we examined this by testing if the interaction of the sensory input on one’s gait and the sensory input on the spatial context is modulating both the emotional experience of the environment and its exploration through head motion. To this end, we asked healthy humans to explore a life-sized Virtual Reality simulation of a forest glade by physically walking around in this environment on two narrow rectangular platforms connected by a plank. The platforms and the plank were presented such that they were either placed on ground or on the top of two high bridge piers. Hence, the forest glade was presented either as a “ground” or as a “height” context. Within these two spatial contexts the virtual plank was projected either on the rigid physical floor or onto a bouncy physical plank. Accordingly, the gait of our participants while they crossed the virtual plank was either “smooth” or “bouncy.” We found that in the height context bouncy gait compared to smooth gait increased the orientation of the head below the horizon and intensified the experience of the environment as negative. Whereas, within the ground context bouncy gait increased the orientation of the head towards and above the horizon and made that the environment was experienced as positive. Our findings suggest that the brain of healthy humans is using the interaction of the sensory input on their gait and the sensory input on the spatial context to regulate both the emotional experience of the environment and its exploration through head motion. Keywords: Neuroscience, Psychology

  17. Cognitive-Behavioral Therapy for Body Dysmorphic Disorder by Proxy.

    Science.gov (United States)

    Greenberg, Jennifer L; Mothi, Suraj Sarvode; Wilhelm, Sabine

    2016-07-01

    Body dysmorphic disorder (BDD) is a distressing or impairing preoccupation with a perceived defect in physical appearance. BDD by proxy (BDDBP) is a significant but understudied variant of BDD in which the primary preoccupation involves perceived imperfections of another person. Like BDD, individuals with BDDBP engage in time-consuming rituals to "fix" the other person's appearance or alleviate distress. Avoidance is common and the impact of BDDBP on social functioning is profound. Cognitive-behavioral therapy (CBT) is the best-studied and most promising psychological treatment for BDD, but no studies have examined its generalizability to the BDDBP variant. We tested feasibility, acceptability, and treatment outcome of CBT modified for BDDBP in a sample of 6 adults with primary BDDBP. Treatment was delivered in weekly individual sessions over 12-20weeks. Mean symptom severity (BDDBP-YBOCS) dropped from the moderately severe range at pretreatment to the subclinical range at posttreatment, t(6)=10.7, p<.001, d=3.3. One hundred percent of treatment completers were responders (≥30% reduction in BDDBP-YBOCS). Insight also improved. Treatment gains were maintained at 3-month follow-up. To our knowledge, this represents the first treatment study for BDDBP. Copyright © 2016. Published by Elsevier Ltd.

  18. Body adiposity, behavior pattern and stress in adolescents

    Directory of Open Access Journals (Sweden)

    Mário Cesar Pires

    2002-12-01

    Full Text Available The objective of this study was to analyze the relationship between the body adiposity index (BAI, behavior pattern and stress of adolescents starting their courses at the Federal Technical School in Santa Catarina, Brazil. 170 subjects participated in the study, comprising 94 male subjects (mean age =14.9±1.0 and 76 female subjects (mean age =14.7±0.7. In addition to measuring body mass (BM and stature (ST in order to characterize the sample, adiposity index was calculated from triciptal and subscapular skinfolds and their sums. The data related to behavior patterns and stress were obtained using a Behavior Inventory and a Stress Symptom Inventory. It was observed, from analysis of the results, that BM and ST were within the percentage range of normality, according to the standard of Santo André, SP. When BAI for male and female subjects was compared, it was higher for female subjects. The sum of skinfolds for both male and female subjects was within the ideal range. BAI was also observed above the ideal level in 24.5% of the male subjects and in 44.7% of the female subjects. In relation to behavior pattern, most of the subjects (59.1% of males and 64.1% of females exhibited Type “A”. Female subjects exhibited more vulnerability to stress (55.2% when compared to male subjects (29.8%. The stress stage with the highest number of subjects was the resistance stage, with 53.9% and 29.8% for female and male subjects, respectively. The results failed to demonstrate an association between BAI and behavior pattern, between BAI and stress or between behavior pattern and stress. It can be concluded that behavior pattern and stress do not infl uence BAI in adolescents. RESUMO O objetivo deste estudo foi analisar a relação entre índice de adiposidade corporal (IAC, padrão de comportamento e estresse em adolescentes ingressantes na Escola Técnica Federal de Santa Catarina. Participaram da amostra 170 adolescentes, 94 do gênero masculino (m

  19. Tattoos and body piercings as indicators of adolescent risk-taking behaviors.

    Science.gov (United States)

    Carroll, Sean T; Riffenburgh, Robert H; Roberts, Timothy A; Myhre, Elizabeth B

    2002-06-01

    This study assessed tattoos and body piercings as markers of risk-taking behaviors in adolescents. A 58-question survey, based on the 1997 Centers for Disease Control and Prevention Youth Risk Behavior Survey, was offered to all adolescent beneficiaries that came to the Adolescent Clinic. The survey contained standard Youth Risk Behavior Survey questions that inquire about eating behavior, violence, drug abuse, sexual behavior, and suicide. Questions about tattoos and body piercings were added for the purposes of this study. Participants with tattoos and/or body piercings were more likely to have engaged in risk-taking behaviors and at greater degrees of involvement than those without either. These included disordered eating behavior, gateway drug use, hard drug use, sexual activity, and suicide. Violence was associated with males having tattoos and with females having body piercings. Gateway drug use was associated with younger age of both tattooing and body piercing. Hard drug use was associated with number of body piercings. Suicide was associated with females having tattoos and younger age of both tattooing and body piercing. Tattoos and body piercings were found to be more common in females than males. Tattoos and/or body piercings can alert practitioners to the possibility of other risk-taking behaviors in adolescents, leading to preventive measures, including counseling. Tattoo and body piercing discovery should be an important part of a health maintenance visit to best direct adolescent medical care.

  20. Rigid-body motion correction of the liver in image reconstruction for golden-angle stack-of-stars DCE MRI.

    Science.gov (United States)

    Johansson, Adam; Balter, James; Cao, Yue

    2018-03-01

    Respiratory motion can affect pharmacokinetic perfusion parameters quantified from liver dynamic contrast-enhanced MRI. Image registration can be used to align dynamic images after reconstruction. However, intra-image motion blur remains after alignment and can alter the shape of contrast-agent uptake curves. We introduce a method to correct for inter- and intra-image motion during image reconstruction. Sixteen liver dynamic contrast-enhanced MRI examinations of nine subjects were performed using a golden-angle stack-of-stars sequence. For each examination, an image time series with high temporal resolution but severe streak artifacts was reconstructed. Images were aligned using region-limited rigid image registration within a region of interest covering the liver. The transformations resulting from alignment were used to correct raw data for motion by modulating and rotating acquired lines in k-space. The corrected data were then reconstructed using view sharing. Portal-venous input functions extracted from motion-corrected images had significantly greater peak signal enhancements (mean increase: 16%, t-test, P <  0.001) than those from images aligned using image registration after reconstruction. In addition, portal-venous perfusion maps estimated from motion-corrected images showed fewer artifacts close to the edge of the liver. Motion-corrected image reconstruction restores uptake curves distorted by motion. Motion correction also reduces motion artifacts in estimated perfusion parameter maps. Magn Reson Med 79:1345-1353, 2018. © 2017 International Society for Magnetic Resonance in Medicine. © 2017 International Society for Magnetic Resonance in Medicine.

  1. Is drive for muscularity related to body checking behaviors in men athletes?

    Directory of Open Access Journals (Sweden)

    Leonardo de Sousa Fortes

    Full Text Available Abstract The aim of this study was to analyze the relationship between drive for muscularity and body checking behaviors in men athletes. Two hundred and twelve Brazilian athletes over 15 years of age participated. We used the Drive for Muscularity Scale (DMS to evaluate the drive for muscularity. The Male Body Checking Questionnaire was used to assess body checking behaviors. The findings demonstrated a relationship between the "body image-oriented muscularity" subscale of the DMS and body checking behaviors (p = 0.001. The results indicated differences in body checking among athletes with high and low levels of drive for muscularity. We concluded that drive for muscularity was related to body checking behaviors in men athletes.

  2. Soft soils reinforced by rigid vertical inclusions

    Directory of Open Access Journals (Sweden)

    Iulia-Victoria NEAGOE

    2013-12-01

    Full Text Available Reinforcement of soft soils by rigid vertical inclusions is an increasingly used technique over the last few years. The system consists of rigid or semi-rigid vertical inclusions and a granular platform for the loads transfer from the structure to the inclusions. This technique aims to reduce the differential settlements both at ground level as below the structure. Reinforcement by rigid inclusions is mainly used for foundation works for large commercial and industrial platforms, storage tanks, wastewater treatment plants, wind farms, bridges, roads, railway embankments. The subject is one of interest as it proves the recently concerns at international level in research and design; however, most studies deal more with the static behavior and less with the dynamic one.

  3. Animal behavior frozen in time: gregarious behavior of Early Jurassic lobsters within an ammonoid body chamber.

    Directory of Open Access Journals (Sweden)

    Adiël A Klompmaker

    Full Text Available Direct animal behavior can be inferred from the fossil record only in exceptional circumstances. The exceptional mode of preservation of ammonoid shells in the Posidonia Shale (Lower Jurassic, lower Toarcian of Dotternhausen in southern Germany, with only the organic periostracum preserved, provides an excellent opportunity to observe the contents of the ammonoid body chamber because this periostracum is translucent. Here, we report upon three delicate lobsters preserved within a compressed ammonoid specimen of Harpoceras falciferum. We attempt to explain this gregarious behavior. The three lobsters were studied using standard microscopy under low angle light. The lobsters belong to the extinct family of the Eryonidae; further identification was not possible. The organic material of the three small lobsters is preserved more than halfway into the ammonoid body chamber. The lobsters are closely spaced and are positioned with their tails oriented toward each other. The specimens are interpreted to represent corpses rather than molts. The lobsters probably sought shelter in preparation for molting or against predators such as fish that were present in Dotternhausen. Alternatively, the soft tissue of the ammonoid may have been a source of food that attracted the lobsters, or it may have served as a long-term residency for the lobsters (inquilinism. The lobsters represent the oldest known example of gregariousness amongst lobsters and decapods in the fossil record. Gregarious behavior in lobsters, also known for extant lobsters, thus developed earlier in earth's history than previously known. Moreover, this is one of the oldest known examples of decapod crustaceans preserved within cephalopod shells.

  4. Cognitive Behavior Therapy with Body Image Exposure for Bulimia Nervosa: A Case Example

    Science.gov (United States)

    Delinsky, Sherrie S.; Wilson, G. Terence

    2010-01-01

    Cognitive behavior therapy (CBT) is an effective treatment for bulimia nervosa (BN). However, among patients with BN, symptom improvement is more pronounced for behavioral eating symptoms (i.e., bingeing and purging) than for body image disturbance, and the persistence of body image disturbance is associated with relapse. The need for more…

  5. Body appreciation, sexual relationship status, and protective sexual behaviors in women.

    Science.gov (United States)

    Winter, Virginia Ramseyer; Satinsky, Sonya

    2014-01-01

    The relationship between body appreciation and sexual risk reduction behavior in women is under-explored. This cross-sectional study examined the relationships between body appreciation, male condom use, and sexually transmitted infection (STI) testing among a community-based sample of women (n=285). Logistic regression results revealed that after controlling for age, BMI, and sexual orientation, having more than one sexual partner moderated body appreciation and current male condom use (OR=4.21, p<.01, CI=1.510-11.726). Body appreciation was not a significant predictor of STI testing in the previous 12 months. This suggests that women with higher body appreciation may be more likely to engage in some protective sexual health behaviors. Interventions that seek to improve body appreciation instead of body size change such as weight loss or gain may encourage certain protective sexual behaviors in women. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Rigidity and symmetry

    CERN Document Server

    Weiss, Asia; Whiteley, Walter

    2014-01-01

    This book contains recent contributions to the fields of rigidity and symmetry with two primary focuses: to present the mathematically rigorous treatment of rigidity of structures, and to explore the interaction of geometry, algebra, and combinatorics. Overall, the book shows how researchers from diverse backgrounds explore connections among the various discrete structures with symmetry as the unifying theme.  Contributions present recent trends and advances in discrete geometry, particularly in the theory of polytopes. The rapid development of abstract polytope theory has resulted in a rich theory featuring an attractive interplay of methods and tools from discrete geometry, group theory, classical geometry, hyperbolic geometry and topology.  The volume will also be a valuable source as an introduction to the ideas of both combinatorial and geometric rigidity theory and its applications, incorporating the surprising impact of symmetry. It will appeal to students at both the advanced undergraduate and gradu...

  7. Birationally rigid varieties

    CERN Document Server

    Pukhlikov, Aleksandr

    2013-01-01

    Birational rigidity is a striking and mysterious phenomenon in higher-dimensional algebraic geometry. It turns out that certain natural families of algebraic varieties (for example, three-dimensional quartics) belong to the same classification type as the projective space but have radically different birational geometric properties. In particular, they admit no non-trivial birational self-maps and cannot be fibred into rational varieties by a rational map. The origins of the theory of birational rigidity are in the work of Max Noether and Fano; however, it was only in 1970 that Iskovskikh and Manin proved birational superrigidity of quartic three-folds. This book gives a systematic exposition of, and a comprehensive introduction to, the theory of birational rigidity, presenting in a uniform way, ideas, techniques, and results that so far could only be found in journal papers. The recent rapid progress in birational geometry and the widening interaction with the neighboring areas generate the growing interest ...

  8. The impact of gender on the assessment of body checking behavior.

    Science.gov (United States)

    Alfano, Lauren; Hildebrandt, Tom; Bannon, Katie; Walker, Catherine; Walton, Kate E

    2011-01-01

    Body checking includes any behavior aimed at global or specific evaluations of appearance characteristics. Men and women are believed to express these behaviors differently, possibly reflecting different socialization. However, there has been no empirical test of the impact of gender on body checking. A total of 1024 male and female college students completed two measures of body checking, the Body Checking Questionnaire and the Male Body Checking Questionnaire. Using multiple group confirmatory factor analysis, differential item functioning (DIF) was explored in a composite of these measures. Two global latent factors were identified (female and male body checking severity), and there were expected gender differences in these factors even after controlling for DIF. Ten items were found to be unbiased by gender and provide a suitable brief measure of body checking for mixed gender research. Practical applications for body checking assessment and theoretical implications are discussed. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Healthy food consumption in young women: The influence of others’ eating behavior and body weight appearance

    NARCIS (Netherlands)

    Stel, M.; van Koningsbruggen, G.M.

    2015-01-01

    People's eating behaviors tend to be influenced by the behaviors of others. In the present studies, we investigated the effect of another person's eating behavior and body weight appearance on healthy food consumption of young women. In Study 1, participants watched a short film fragment together

  10. Healthy food consumption in young women : The influence of others' eating behavior and body weight appearance

    NARCIS (Netherlands)

    Stel, M.; van Koningsbruggen, G.M.

    2015-01-01

    People's eating behaviors tend to be influenced by the behaviors of others. In the present studies, we investigated the effect of another person's eating behavior and body weight appearance on healthy food consumption of young women. In Study 1, participants watched a short film fragment together

  11. Stress Symptoms: Effects on Your Body and Behavior

    Science.gov (United States)

    ... heart disease, obesity and diabetes. Common effects of stress on your body Headache Muscle tension or pain ... drive Stomach upset Sleep problems Common effects of stress on your mood Anxiety Restlessness Lack of motivation ...

  12. Control of body weight by eating behavior in children

    Directory of Open Access Journals (Sweden)

    Modjtaba eZandian

    2015-10-01

    Full Text Available Diet, exercise, and pharmacological interventions have limited effects in counteracting the worldwide increase in pediatric body weight. Moreover, the promise that individualized drug design will work to induce weight loss appears to be exaggerated. We suggest that the reason for this limited success is that the cause of obesity has been misunderstood. Body weight is mainly under external control; our brain permits us to eat under most circumstances, and unless the financial or physical cost of food is high, eating and body weight increase by default. When energy-rich, inexpensive foods are continually available, people need external support to maintain a healthy body weight. Weight loss can thereby be achieved by continuous feedback on how much and how fast to eat on a computer screen.

  13. BEHAVIORAL PECULIARITIES IN PATIENTS WITH SURPLUS BODY MASS AND OBESITY

    Directory of Open Access Journals (Sweden)

    A. E. Bobrov

    2014-01-01

    Full Text Available Background: Eating in obesity represents behavioral systems more powerful than conscious self-control. Aim: To study the obese patients’ behavior with the help of clinical-psychopathological and personal style criteria. Materials and methods: A total of 149 patients (aged 19-69 years, who sought medical help due to obesity or overweight were examined. Their physical condition was satisfactory and concomitant somatic diseases were compensated. Patients’ behavior was assessed by diagnostic criteria ICD-10 as well as with a Minnesota Multiphasic Personality Inventory (psychological testing. Results: It was established that psychical impairments existed in 98 (65.8% patients. The anxiety disorders (in 65 patients, 43.6% and affective ones (in 41 patients, 31.5% were noted most frequently. Factor analysis of the psychological test data revealed 5 main styles of behavior in patients with overweight and obesity: borderline, hyperthymic, dysthymic, sensitive, and undifferentiated. Neither these behavioral styles nor the frequency of disorders corresponded to the degree of obesity. Conclusion: Disturbances of eating self-regulation in obesity are associated with different behavioral styles, which are not specific for mental disorders only. These behavioral styles are described in the study as well as corresponding psychological mechanisms of overeating.

  14. Self-compassionate actions and disordered eating behavior in women: The mediator effect of body appreciation

    Directory of Open Access Journals (Sweden)

    Andreia Máximo

    2017-09-01

    Conclusions: Present results suggest that self-compassionate actions hold a protective effect on eating behavior through higher levels of respect and appreciation toward body image, despite body weight, shape, and imperfections. The ability to act following self-compassionate motivations seems to contribute to higher levels of body image appreciation, which reflects in a lower susceptibility to adopt disordered eating attitudes and behaviors. The present study seems to represent an important contribution to research and clinical practice and underlines the importance of including strategies to develop self-compassionate and body appreciation competencies in programs to prevent and intervene in the area of eating psychopathology.

  15. Experimental study on the cracking behavior of reinforced concrete hollow cylinders subjected to temperature gradient and the assessment of decrease in flexural rigidity due to cracking

    International Nuclear Information System (INIS)

    Aoyagi, Yukio; Onuma, Hiroshi; Okazawa, Takao

    1976-01-01

    Altough the consideration of thermal stress constitutes one of the primary factors governing the design of the hollow cylindrical structures made of reinforced concrete and subjected to temperature gradient, such as radiation-shielding walls and reactor containment vessels, the method of rationally evaluating the safety to such stress has not been established so far. The purposes of this study are to investigate the conditions under which cracks initiate in reinforced concrete structures due to temperature gradient, and to evaluate the decreases in the flexural rigidity after cracking, mainly on the basis of experiment. Three hollow cylinders with top and bottom slabs, 120 cm height and 100 cm outside diameter, were tested. The cylinders were externally cooled by being immersed in water, and internally heated by circulating hot water through the cavities. The maximum temperature difference of 65 deg C was attained. The strain was measured, and the crack patterns were observed. A reinforced concrete beam of 3.8 m length was subjected to temperature difference of 65 deg C. Horizontal cracks appeared first at 27 deg C, and vertical cracks followed at 31 deg C difference at the middle of cylindrical walls. It was assumed that the first cracks appear at the tensile strain of 100 x 10 -6 , and the calculated result was agreed fairly well with the observed temperature difference. The rational method for evaluating the decrease in flexural rigidity due to cracking was proposed by the authors. (Kako, I.)

  16. Interrelationships among Nutrition Knowledge, Attitudes, Behaviors and Body Satisfaction

    Science.gov (United States)

    Dissen, Anthony R.; Policastro, Peggy; Quick, Virginia; Byrd-Bredbenner, Carol

    2011-01-01

    Purpose: Little is known about interrelationships among nutrition knowledge, attitude, dietary intake, and body satisfaction, which are important variables that play a role in nutrition education interventions. This paper aims to focus on these interrelationships. Design/methodology/approach: Students (n = 279; 20.12 plus or minus 1.75SD years)…

  17. High frequency body mass measurement, feedback, and health behaviors

    NARCIS (Netherlands)

    Kooreman, P.; Scherpenzeel, A.

    We analyze weight and fat percentage measurements of respondents in an online general population panel in the Netherlands, collected using wireless scales, with an average frequency of 1.6 measurements per week. First, we document the existence of a weekly cycle; body mass is lowest on Fridays and

  18. Association Among Internet Usage, Body Image and Eating Behaviors of Secondary School Students.

    Science.gov (United States)

    Kaewpradub, Natthakarn; Kiatrungrit, Komsan; Hongsanguansri, Sirichai; Pavasuthipaisit, Chosita

    2017-08-25

    Presently, the internet plays a big role in daily life, especially for adolescents. In this age group, they are more concerned about their face and body shape. Despite the numerous studies on the effect traditional media has on body image, very few have focused on the effect of newer forms of media (e.g. online media). And almost none have looked at the relationship between time spent online and body image. To study the associations between time spent on the internet, body image satisfaction and eating behaviors of students grades 7 to 12 in the Thai educational system. The sample group included 620 students, who were selected using simple random sampling from 6 secondary schools in Bangkok. Data were collected using the Media and Internet use behavior questionnaires, The Body-Esteem Scale for Adolescents and Adults: Thai version (BESAA), Drive for Muscularity Scale (DMS: males only), The Rosenberg Self-Esteem Scale: Thai version, Eating Attitude Test-26: Thai version (EAT-26) and the eating behaviors at risk of obesity questionnaire. Mean (sd) age of the sample was 15.7 (1.9) years, 246 participants (39.7%) were male and 374 (60.3%) were female. Using the internet and social networks for content related to body image and eating behaviors, was negatively associated with body image satisfaction but positively associated with inappropriate eating attitudes/behaviors, binging, purging, use of laxatives/diuretics and drive for muscularity with respect to behaviors and attitudes, and was associated with eating behaviors that carried a risk for obesity. Time spent on internet, especially engaged in activities related to self-image, and eating attitudes and behaviors, were associated with a decrease in body image satisfaction and problematic eating behaviors.

  19. The Effects of Pubertal Timing on Body Image, School Behavior, and Deviance.

    Science.gov (United States)

    Duncan, Paula Duke; And Others

    1985-01-01

    Data from the National Health Examination Survey, a national probability sample of children and youth aged 12-17, was used to investigate the relationships between maturational timing and body image, school behavior, and deviance. (Author/LMO)

  20. Body shape, burst speed and escape behavior of larval anurans

    Science.gov (United States)

    Gage H. Dayton; Daniel Saenz; Kristen A. Baum; R. Brian Langerhans; Thomas J. DeWitt

    2005-01-01

    Variation in behavior, morphology and life history traits of larval anurans across predator gradients, and consequences of that variation, have been abundantly studied. Yet the functional link between morphology and burst-swimming speed is largely unknown. We conducted experiments with two divergent species of anurans, Scaphiopus holbrookii and

  1. Rigid supersymmetry with boundaries

    Energy Technology Data Exchange (ETDEWEB)

    Belyaev, D.V. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Van Nieuwenhuizen, P. [State Univ. of New York, Stony Brook, NY (United States). C.N. Yang Inst. for Theoretical Physics

    2008-01-15

    We construct rigidly supersymmetric bulk-plus-boundary actions, both in x-space and in superspace. For each standard supersymmetric bulk action a minimal supersymmetric bulk-plus-boundary action follows from an extended F- or D-term formula. Additional separately supersymmetric boundary actions can be systematically constructed using co-dimension one multiplets (boundary superfields). We also discuss the orbit of boundary conditions which follow from the Euler-Lagrange variational principle. (orig.)

  2. Left ventricular rigid body rotation in a diffuse large B-cell lymphoma patient with cardiac involvement: A case from the three-dimensional speckle-tracking echocardiographic MAGYAR-Path Study.

    Science.gov (United States)

    Földeák, Dóra; Kalapos, Anita; Domsik, Péter; Sinkó, Mária; Szeleczki, Nóra; Bagdi, Enikő; Krenács, László; Forster, Tamás; Borbényi, Zita; Nemes, Attila

    2017-02-01

    Secondary myocardial involvement by diffuse large B-cell lymphoma is a rare occurrence. Left ventricular (LV) twist is considered an essential part of LV function. In normal circumstances LV twist results from the movement of two orthogonally oriented muscular bands of a helical myocardial structure with consequent clockwise rotation of the base and counterclockwise rotation of the apex. Three-dimensional (3D) speckle-tracking echocardiography (3DSTE) has been found to be feasible for non-invasive 3D quantification of LV wall motion and rotational mechanics. The present report aimed to assess LV twisting motion in a patient with diffuse large B-cell lymphoma with positron emission tomography/computer tomography-proven cardiac involvement by 3DSTE. During 3DSTE, reduction in some segmental radial, longitudinal, circumferential, area and 3D LV strains were found. Apical and basal LV rotations were found to be in the same counterclockwise direction, confirming near absence of LV twist - so-called rigid body rotation. Copyright © 2016 Sociedade Portuguesa de Cardiologia. Publicado por Elsevier España, S.L.U. All rights reserved.

  3. Enstatite, Mg/sub 2/Si/sub 2/O/sub 6/: A neutron diffraction refinement of the crystal structure and a rigid-body analysis of the thermal vibration

    Energy Technology Data Exchange (ETDEWEB)

    Ghose, S.; Schomaker, V.; McMullan, R.K.

    1986-01-01

    Synthetic enstatite, Mg/sub 2/Si/sub 2/O/sub 6/, is orthorhombic, space group Pbca, with eight formula units per cell and lattice parameters a = 18.235(3), b = 8.818(1), c = 5.179(1) A at 23/sup 0/C. A least-squares structure refinement based on 1790 neutron intensity data converged with an agreement factor R(F/sup 2/) = 0.032, yielding Mg-O and Si-O bond lengths with standard deviations of 0.0007 and 0.0008 A, respectively. The variations observed in the Si-O bond lengths within the silicate tetrahedra A and B are caused by the differences in primary coordination of the oxygen atoms and the proximity of the magnesium ions to the silicon atoms. The latter effect is most pronounced for the bridging bonds of tetrahedron. A. The smallest O-Si-O angle is the result of edge-sharing by the Mg(2) octahedron and the A tetrahedron. An analysis of rigid-body thermal vibrations of the two crystallographically independent (SiO/sub 4/) tetrahedra indicates considerable librational motion, leading to a thermal correction of apparent Si-O bond lengths as large as +0.002 A at room temperature.

  4. Crystallization behavior of nanocomposites based on poly(L-lactide) and layered double hydroxides - Unbiased determination of the rigid amorphous phases due to the crystals and the nanofiller

    Science.gov (United States)

    Schoenhals, Andreas; Leng, Jing; Wurm, Andreas; Schick, Christoph

    Semicrystalline polymers have to be described by a three phase model consisting of a mobile amorphous (MAF), a crystalline (CF), and a rigid amorphous fraction (RAF). For nanocomposites based on a semicrystalline polymer the RAF is due to both the crystallites (RAFcrystal) and the filler (RAFfiller) . In most cases a separation of both contributions is not possible without further assumptions. Here polymer nanocomposite based on poly(L-lactide) and layered double hydroxide nanofiller were prepared. Due to the low crystallization rate of PLA its crystallization can be suppressed by a high enough cooling rate, and the RAF is due only to the nanofiller. The MAF, CF, and RAF were estimated by Temperature Modulated DSC. For the first time CF, MAF, RAFcrystal, and RAFfiller could be estimated without any assumption. Two different systems with a different degree of exfoliation were prepared and discussed in detail.

  5. The influence of social anxiety on the body checking behaviors of female college students.

    Science.gov (United States)

    White, Emily K; Warren, Cortney S

    2014-09-01

    Social anxiety and eating pathology frequently co-occur. However, there is limited research examining the relationship between anxiety and body checking, aside from one study in which social physique anxiety partially mediated the relationship between body checking cognitions and body checking behavior (Haase, Mountford, & Waller, 2007). In an independent sample of 567 college women, we tested the fit of Haase and colleagues' foundational model but did not find evidence of mediation. Thus we tested the fit of an expanded path model that included eating pathology and clinical impairment. In the best-fitting path model (CFI=.991; RMSEA=.083) eating pathology and social physique anxiety positively predicted body checking, and body checking positively predicted clinical impairment. Therefore, women who endorse social physique anxiety may be more likely to engage in body checking behaviors and experience impaired psychosocial functioning. Published by Elsevier Ltd.

  6. Short-term changes in affective, behavioral, and cognitive components of body image after bariatric surgery.

    Science.gov (United States)

    Williams, Gail A; Hudson, Danae L; Whisenhunt, Brooke L; Stone, Megan; Heinberg, Leslie J; Crowther, Janis H

    2018-04-01

    Many bariatric surgery candidates report body image concerns before surgery. Research has reported post-surgical improvements in body satisfaction, which may be associated with weight loss. However, research has failed to comprehensively examine changes in affective, behavioral, and cognitive body image. This research examined (1) short-term changes in affective, behavioral, and cognitive components of body image from pre-surgery to 1- and 6-months after bariatric surgery, and (2) the association between percent weight loss and these changes. Participants were recruited from a private hospital in the midwestern United States. Eighty-eight females (original N = 123; lost to follow-up: n = 15 at 1-month and n = 20 at 6-months post-surgery) completed a questionnaire battery, including the Body Attitudes Questionnaire, Body Checking Questionnaire, Body Image Avoidance Questionnaire, and Body Shape Questionnaire, and weights were obtained from patients' medical records before and at 1- and 6-months post-surgery. Results indicated significant decreases in body dissatisfaction, feelings of fatness, and body image avoidance at 1- and 6-months after bariatric surgery, with the greatest magnitude of change occurring for body image avoidance. Change in feelings of fatness was significantly correlated with percent weight loss at 6-months, but not 1-month, post-surgery. These findings highlight the importance of examining short-term changes in body image from a multidimensional perspective in the effort to improve postsurgical outcomes. Unique contributions include the findings regarding the behavioral component of body image, as body image avoidance emerges as a particularly salient concern that changes over time among bariatric surgery candidates. Copyright © 2018 American Society for Bariatric Surgery. Published by Elsevier Inc. All rights reserved.

  7. Body Weight Perception, Unhealthy Weight Control Behaviors, and Suicidal Ideation among Korean Adolescents

    Science.gov (United States)

    Kim, Dong-Sik; Cho, Youngtae; Cho, Sung-Il; Lim, In-Sook

    2009-01-01

    Background: This study examined the mediating function of body weight perception (BWP) in the relation between body mass index (BMI) and unhealthy weight control behaviors (UWCBs; eg, fasting, using diet pills, or laxatives), and between BMI and suicidal ideation. It also explored the correlation between exposure to multiple UWCBs and suicidal…

  8. The link between women's body image disturbances and body-focused cancer screening behaviors: a critical review of the literature and a new integrated model for women.

    Science.gov (United States)

    Ridolfi, Danielle R; Crowther, Janis H

    2013-03-01

    A large body of literature demonstrates the association between body image disturbances and health compromising behaviors among women (e.g., pathological eating, substance use, inappropriate exercise). However, given that disturbed body image is a pervasive problem, it is likely inversely related to health maintenance behaviors. Cancer screenings for breast, skin, and cervical cancer represent an important type of health maintenance behavior, yet adherence rates are low. Given the body-focused nature of these screenings, body image may be a salient predictor. This paper reviews the literature on the relationship between body image disturbances and cancer screening behaviors among women culminating in the proposal of a theoretical model. This model posits that body shame and body avoidance predict performance of cancer screenings and that variables drawn from the cancer literature, including risk perception, health anxiety, subjective norms, and self-efficacy, may moderate this relationship. Clinical implications and suggestions for research are discussed. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Sedentary behaviors, physical activity behaviors, and body fat in 6-year-old children: the generation R study.

    Science.gov (United States)

    Wijtzes, Anne I; Bouthoorn, Selma H; Jansen, Wilma; Franco, Oscar H; Hofman, Albert; Jaddoe, Vincent Wv; Raat, Hein

    2014-08-15

    Childhood overweight and obesity is a major public health concern. Knowledge on modifiable risk factors is needed to design effective intervention programs. This study aimed to assess associations of children's sedentary behaviors (television viewing and computer game use) and physical activity behaviors (sports participation, outdoor play, and active transport to/from school) with three indicators of body fat, i.e., percent fat mass, body mass index (BMI) standard deviation scores, and weight status (normal weight, overweight). Cross-sectional data from 5913 6-year-old ethnically diverse children were analyzed. Children's weight and height were objectively measured and converted to BMI. Weight status was defined according to age- and sex-specific cut-off points of the International Obesity Task Force. BMI standard deviation scores were created, based on Dutch reference growth curves. Fat mass was measured my dual-energy X-ray absorptiometry (DXA). Sedentary and physical activity behaviors were assessed by parent-reported questionnaires. Series of logistic and linear regression analyses were performed, controlling for confounders (i.e., socio-demographic factors, family lifestyle factors, and other sedentary behaviors and physical activity behaviors). Sports participation was inversely associated with fat mass (p sedentary behaviors and physical activity behaviors. No other independent associations were observed. The results of this study indicate that sports participation is inversely associated with percent body fat among ethnically diverse 6-year-old children. More research in varied populations including objective measurements and longitudinal designs are needed to confirm these current results.

  10. [Relationship between eating behavior and distribution of body fat].

    Science.gov (United States)

    Guagnano, M T; Blasioli, A; Del Ponte, A; Sensi, S

    1990-01-01

    In these recent few years the study of the pathogenesis of obesity include the observation of the difference in eating behaviour between obese and non obese subjects. Therefore, current therapies now take into account, among others, also a program of behavioural therapy. On the other hand, recent studies have revealed the role of different body fat distribution on the obesity prognosis, especially considering cardiovascular risk factors. To this purpose much attention has been focused on the measurement of waist and hips circumferences and their ratio (WHR) considered important predictors of risk associated with obesity. Aim of this study was the observation of some differences in eating habits and psychological status during a 24-hr period in relationship with the android or gynecoid type of obesity. 102 outpatients were divided in two groups: 1) with WHR less than 0.85; 2) with WHR greater than or equal to 0.85. All subjects were given a questionnaire in which by a scale from 0 to 3 they expressed their appetite sensation during different hours of the day. In addition, they indicated their motivation to loose body weight. Our results demonstrated that subjects with WHR greater than or equal to 0.85 showed higher appetite sensation, during the whole day, with a peak at lunch, in comparison with subjects with WHR less than 0.85. Subjects with gynecoid type of obesity seemed to pay much attention to their body image than subjects with android type of obesity and complained less physical disorders than subjects of the second group. These preliminary data seem to suggest a non-secondary role of behavioural pattern in obesity also by affecting the different regional fat distribution.

  11. Body image and eating disordered behavior in a community sample of Black and Hispanic women.

    Science.gov (United States)

    Hrabosky, Joshua I; Grilo, Carlos M

    2007-01-01

    The current study examined body image concerns and eating disordered behaviors in a community sample of Black and Hispanic women. In addition, this study explored whether there are ethnic differences in the correlates or in the prediction of body image concerns. Participants were 120 (67 Black and 53 Hispanic) women who responded to advertisements to participate in a study of women and health. Participants completed a battery of established self-report measures to assess body image, eating disordered behaviors, and associated psychological domains. Black and Hispanic women did not differ significantly in their self-reports of body image, eating disordered behaviors, or associated psychological measures. Comparisons performed separately within both ethnic groups revealed significant differences by weight status, with a general graded patterning of greater concerns in obese than overweight than average weight groups. In terms of predicting body image, multiple regression analyses testing a number of variables, including BMI, performed separately for Black and Hispanic women revealed that eating concern and depressive affect were significant predictors of body image concern for both groups. Overall, Black and Hispanic women differed little in their self-reports of body image, eating-disordered features, and depressive affect. Higher weight was associated with a general pattern of increased body image concerns and features of eating disorders in both groups and with binge eating in Black women. Eating concerns and depressive affect emerged as significant independent predictors of body image for both ethnic groups.

  12. Perceived Body Image, Eating Behavior, and Sedentary Activities and Body Mass Index Categories in Kuwaiti Female Adolescents

    Directory of Open Access Journals (Sweden)

    Lemia H. Shaban

    2016-01-01

    Full Text Available Background. The State of Kuwait has a growing obesity epidemic in both genders and all age groups; however, obesity rates in the young seem to be rising. Methods. We conducted a cross-sectional survey in 169 Kuwaiti female adolescents attending both private and public schools spanning the six governorates in the State of Kuwait in order to explore female adolescents’ self-image, body dissatisfaction, type of school (private versus public, TV viewing, and computer games and their relationship to body mass index. Results. Approximately half the students classified as obese perceived their body image to lie in the normal range. Females in the obese category were the most dissatisfied with their body image, followed by those in the overweight category. Eating behavior, level of physical activity, school type, television viewing, computer/video usage, and desired BMI were not significantly associated with level of obesity. Conclusion. This study was one of the few studies to assess adolescent females’ body image dissatisfaction in relation to obesity in the State of Kuwait. The results suggest that including body image dissatisfaction awareness into obesity prevention programs would be of value.

  13. Rigid body essential X-ray crystallography

    DEFF Research Database (Denmark)

    Bjerrum, Esben Jannik; Biggin, Philip C

    2008-01-01

    The ligand-binding domain (LBD) from the ionotropic glutamate receptor subtype 2 (GluR2) has been shown to adopt a range of ligand-dependent conformational states. These states have been described in terms of the rotation required to fit subdomain (lobe) 2 following superposition of subdomain (lo...

  14. Thinking meta-theoretically about the role of internalization in the development of body dissatisfaction and body change behaviors.

    Science.gov (United States)

    Karazsia, Bryan T; van Dulmen, Manfred H M; Wong, Kendal; Crowther, Janis H

    2013-09-01

    Internalization of societal standards of physical attractiveness (i.e., internalization of the thin ideal for women and internalization of the mesomorphic ideal for men) is a widely studied and robust risk factor for body dissatisfaction and maladaptive body change behaviors. Substantial empirical research supports internalization as both a mediator and a moderator of the relation between societal influences and body dissatisfaction. In this paper, a primer on mediation and moderation is followed by a review of literature and discussion of the extent to which internalization can theoretically fulfill the roles of both mediation and moderation. The literature review revealed a stark contrast in research design (experimental versus non-experimental design) when alternate conceptualizations of internalization are adopted. A meta-theoretical, moderated mediation model is presented. This model integrates previous research and can inform future empirical and clinical endeavors. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Modeling the behavior of human body tissues on penetration

    Science.gov (United States)

    Conci, A.; Brazil, A. L.; Popovici, D.; Jiga, G.; Lebon, F.

    2018-02-01

    Several procedures in medicine (such as anesthesia, injections, biopsies and percutaneous treatments) involve a needle insertion. Such procedures operate without vision of the internal involved areas. Physicians and anesthetists rely on manual (force and tactile) feedback to guide their movements, so a number of medical practice is strongly based on manual skill. In order to be expert in the execution of such procedures the medical students must practice a number of times, but before practice in a real patient they must be trained in some place and a virtual environment, using Virtual Reality (VR) or Augmented Reality (AR) is the best possible solution for such training. In a virtual environment the success of user practices is improved by the addition of force output using haptic device to improve the manual sensations in the interactions between user and computer. Haptic devices enable simulate the physical restriction of the diverse tissues and force reactions to movements of operator hands. The trainees can effectively "feel" the reactions to theirs movements and receive immediate feedback from the actions executed by them in the implemented environment. However, in order to implement such systems, the tissue reaction to penetration and cutting must be modeled. A proper model must emulate the physical sensations of the needle action in the skin, fat, muscle, and so one, as if it really done in a patient that is as they are holding a real needle and feeling each tissue resistance when inserting it through the body. For example an average force value for human skin puncture is 6.0 N, it is 2.0 N for subcutaneous fat tissue and 4.4 N for muscles: this difference of sensations to penetration of each layers trespassed by the needle makes possible to suppose the correct position inside the body. This work presents a model for tissues before and after the cutting that with proper assumptions of proprieties can model any part of human body. It was based on experiments

  16. Body perceptions and health behaviors in an online bodybuilding community.

    Science.gov (United States)

    Smith, Aaron C T; Stewart, Bob

    2012-07-01

    In this article we explore the social constructions, body perceptions, and health experiences of a serious recreational and competitive bodybuilder and powerlifter community. Data were obtained from a discussion forum appearing within an online community dedicated to muscular development. Forum postings for a period of 36 months were transposed to QSR NVivo, in which a narrative-based analytical method employing Gee's coding approach was employed. We used a priori codes based on Bourdieu's multipronged conceptual categories of social field, habitus, and capital accumulation as a theoretical frame. Our results expose an extreme social reality held by a devoted muscle-building community with a fanatical obsession with muscular hypertrophy and any accouterment helpful in its acquisition, from nutrition and supplements to training regimes and anabolic androgenic substances. Few health costs were considered too severe in this muscular meritocracy, where the strong commanded deference and the massive dominated the social field.

  17. Association between perception of body image and stages of behavioral changes among physical education university students

    Directory of Open Access Journals (Sweden)

    Elisa Pinheiro Ferrari

    2012-08-01

    The objective of this study was to evaluate the association between the percep­tion of body image and the stages of behavioral changes related to physical activity among Physical Education Students. Two hundred thirty six students were included. We measured the perception of body image (silhouettes scale, the stages of changes in behavior related to physical activity using a questionnaire developed by Marcus et al., and socio-demographic variables (gender, age, parental education, marital status, course, employment situation, housing, period of study and income. We used descriptive analysis, chi-square test, Fischer’s exact test, crude and adjusted multinomial regression to estimate the odds ratio (OR and 95% confidence intervals (95% CI. The prevalence of physically inactive behavior was 18.2% for males and 23.9% for females. Dissatisfaction with body image was associated with the stages of behavioral changes in females, with women with physically inactive behavior having greater odds of experiencing dissatisfaction with their body image, both for underweight (OR: 9.69; 95% CI: 1.05-89.30 and overweight (OR: 5.49; 95% CI: 1.07-28.11 when compared with women who were satisfied with their body image. We suggest the development of in­terventions aimed at the adoption of regular physical activity in order to promote greater satisfaction with body image.

  18. Associations of body weight perception and weight control behaviors with problematic internet use among Korean adolescents.

    Science.gov (United States)

    Park, Subin; Lee, Yeeun

    2017-05-01

    We examined the association of body mass index (BMI), body weight perception, and weight control behaviors with problematic Internet use in a nationwide sample of Korean adolescents. Cross-sectional data from the 2010 Korean Youth Risk Behavior Web-based Survey collected from 37,041 boys and 33,655 girls in middle- and high- schools (grades 7-12) were analyzed. Participants were classified into groups based on BMI (underweight, normal weight, overweight, and obese), body weight perception (underweight, normal weight, and overweight), and weight control behavior (no weight control behavior, appropriate weight control behavior, inappropriate weight control behavior). The risk of problematic Internet use was assessed with the Korean Internet Addiction Proneness Scale for Youth-Short Form. Both boys and girls with inappropriate weight control behavior were more likely to have problematic Internet use. Underweight, overweight, and obese boys and girls were more likely to have problematic Internet use. For both boys and girls, subjective perception of underweight and overweight were positively associated with problematic Internet use. Given the negative effect of inappropriate weight control behavior, special attention needs to be given to adolescents' inappropriate weight control behavior, and an educational intervention for adolescents to control their weight in healthy ways is needed. Copyright © 2017. Published by Elsevier B.V.

  19. APPLICATION OF RIGID LINKS IN STRUCTURAL DESIGN MODELS

    Directory of Open Access Journals (Sweden)

    Sergey Yu. Fialko

    2017-09-01

    Full Text Available A special finite element modelling rigid links is proposed for the linear static and buckling analysis. Unlike the classical approach based on the theorems of rigid body kinematics, the proposed approach preserves the similarity between the adjacency graph for a sparse matrix and the adjacency graph for nodes of the finite element model, which allows applying sparse direct solvers more effectively. Besides, the proposed approach allows significantly reducing the number of nonzero entries in the factored stiffness matrix in comparison with the classical one, which greatly reduces the duration of the solution. For buckling problems of structures containing rigid bodies, this approach gives correct results. Several examples demonstrate its efficiency.

  20. The role of body awareness and mindfulness in the relationship between exercise and eating behavior.

    Science.gov (United States)

    Martin, Rachel; Prichard, Ivanka; Hutchinson, Amanda D; Wilson, Carlene

    2013-12-01

    This study examined the potential mediating roles of mindfulness and body awareness in the relationship between exercise and eating behavior. Female exercisers (N = 159) recruited from fitness centers, yoga centers, and the community completed a questionnaire incorporating measures of exercise behavior, body awareness, trait mindfulness, mindful eating, dietary intake, and disordered eating symptoms. Participation in yoga was associated with significantly lower disordered eating (mediated by body awareness), whereas the amount of time spent participating in cardio-based exercise was associated with greater eating disturbance. The relationships between amount of exercise and actual food intake were not mediated by trait mindfulness or body awareness. The differential findings for dietary intake and disordered eating indicate that the body awareness cultivated in different forms of exercise may be more beneficial for clinical populations or those at risk for eating disorders than for modifying actual dietary intake in the general population.

  1. Body-related self-conscious emotions relate to physical activity motivation and behavior in men.

    Science.gov (United States)

    Castonguay, Andree L; Pila, Eva; Wrosch, Carsten; Sabiston, Catherine M

    2015-05-01

    The aim of this study was to examine the associations between the body-related self-conscious emotions of shame, guilt, and pride and physical activity motivation and behavior among adult males. Specifically, motivation regulations (external, introjected, indentified, intrinsic) were examined as possible mediators between each of the body-related self-conscious emotions and physical activity behavior. A cross-sectional study was conducted with adult men (N = 152; Mage = 23.72, SD = 10.92 years). Participants completed a questionnaire assessing body-related shame, guilt, authentic pride, hubristic pride, motivational regulations, and leisure-time physical activity. In separate multiple mediation models, body-related shame was positively associated with external and introjected regulations and negatively correlated with intrinsic regulation. Guilt was positively linked to external, introjected, and identified regulations. Authentic pride was negatively related to external regulation and positively correlated with both identified and intrinsic regulations and directly associated with physical activity behavior. Hubristic pride was positively associated with intrinsic regulation. Overall, there were both direct and indirect effects via motivation regulations between body-related self-conscious emotions and physical activity (R(2) shame = .15, guilt = .16, authentic pride = .18, hubristic pride = .16). These findings highlight the importance of targeting and understanding self-conscious emotions contextualized to the body and links to motivation and positive health behavior among men. © The Author(s) 2014.

  2. Tile-based rigidization surface parametric design study

    Science.gov (United States)

    Giner Munoz, Laura; Luntz, Jonathan; Brei, Diann; Kim, Wonhee

    2018-03-01

    Inflatable technologies have proven useful in consumer goods as well as in more recent applications including civil structures, aerospace, medical, and robotics. However, inflatable technologies are typically lacking in their ability to provide rigid structural support. Particle jamming improves upon this by providing structures which are normally flexible and moldable but become rigid when air is removed. Because these are based on an airtight bladder filled with loose particles, they always occupy the full volume of its rigid state, even when not rigidized. More recent developments in layer jamming have created thin, compact rigidizing surfaces replacing the loose volume of particles with thinly layered surface materials. Work in this area has been applied to several specific applications with positive results but have not generally provided the broader understanding of the rigidization performance as a function of design parameters required for directly adapting layer rigidization technology to other applications. This paper presents a parametric design study of a new layer jamming vacuum rigidization architecture: tile-based vacuum rigidization. This form of rigidization is based on layers of tiles contained within a thin vacuum bladder which can be bent, rolled, or otherwise compactly stowed, but when deployed flat, can be vacuumed and form a large, flat, rigid plate capable of supporting large forces both localized and distributed over the surface. The general architecture and operation detailing rigidization and compliance mechanisms is introduced. To quantitatively characterize the rigidization behavior, prototypes rigidization surfaces are fabricated and an experimental technique is developed based on a 3-point bending test. Performance evaluation metrics are developed to describe the stiffness, load-bearing capacity, and internal slippage of tested prototypes. A set of experimental parametric studies are performed to better understand the impact of

  3. Cognitive-behavioral therapy for body dysmorphic disorder: a review of its efficacy

    Directory of Open Access Journals (Sweden)

    Prazeres AM

    2013-02-01

    Full Text Available Angélica M Prazeres,1 Antônio L Nascimento,1 Leonardo F Fontenelle1,21Anxiety and Depression Research Program, Institute of Psychiatry, Universidade Federal do Rio de Janeiro, Rio de Janeiro, 2Department of Psychiatry and Mental Health, Universidade Federal Fluminense, Hospital Universitário Antonio Pedro, Niterói, BrazilAbstract: The aim of this study was to review the efficacy of different methods of cognitive and/or behavioral therapies used to treat body dysmorphic disorder. We evaluated all case series, open studies, controlled trials, and meta-analyses of cognitive and/or behavioral treatment approaches to body dysmorphic disorder published up to July 2012, identified through a search in the PubMed/Medline, PsycINFO, ISI Web of Knowledge, and Scopus databases. Our findings indicate that individual and group cognitive behavioral therapies are superior to waiting list for the treatment of body dysmorphic disorder. While the efficacy of cognitive therapy is supported by one controlled trial, utility of behavioral therapy is suggested by one open study and one controlled relapse prevention follow-up study. There is a pressing need to conduct head-to-head studies, with appropriate, active, control treatment groups, in order to examine further the efficacy of cognitive and/or behavioral therapies for body dysmorphic disorder.Keywords: dysmorphophobia, behavioral therapy, cognitive therapy, literature review

  4. Sex-related online behaviors and adolescents' body and sexual self-perceptions.

    Science.gov (United States)

    Doornwaard, Suzan M; Bickham, David S; Rich, Michael; Vanwesenbeeck, Ine; van den Eijnden, Regina J J M; ter Bogt, Tom F M

    2014-12-01

    This study investigated: (1) the prevalence and development of 2 receptive (sexually explicit Internet material [SEIM] use and sexual information seeking) and 2 interactive (cybersex and general social networking site [SNS] use) online behaviors in adolescence; (2) whether development of these behaviors predict adolescents' body and sexual self-perceptions; and (3) whether parental strategies regarding adolescents' Internet use reduce engagement in sex-related online behaviors. Four-wave longitudinal data among 1132 seventh- to 10th-grade Dutch adolescents (mean age at wave 1: 13.95 years; 52.7% boys) were collected. Developmental trajectories of sex-related online behaviors were estimated by using latent growth curve modeling. Self-perception outcomes at wave 4 and parental strategies predicting online behaviors were investigated by adding regression paths to growth models. Boys occasionally and increasingly used SEIM. Patterns for girls' SEIM use and boys' and girls' sexual information seeking and cybersex were consistently low. SNS use, however, was a common, daily activity for both. Higher initial levels and/or faster increases in sex-related online behaviors generally predicted less physical self-esteem (girls' SNS use only), more body surveillance, and less satisfaction with sexual experience. Private Internet access and less parental rule setting regarding Internet use predicted greater engagement in sex-related online behaviors. Although most sex-related online behaviors are not widespread among youth, adolescents who engage in such behaviors are at increased risk for developing negative body and sexual self-perceptions. Particular attention should be paid to adolescents' SNS use because this behavior is most popular and may, through its interactive characteristics, elicit more critical self-evaluations. Prevention efforts should focus on parents' role in reducing risky sex-related online behaviors. Copyright © 2014 by the American Academy of Pediatrics.

  5. Treatment-Associated Changes in Body Composition, Health Behaviors, and Mood as Predictors of Change in Body Satisfaction in Obese Women: Effects of Age and Race/Ethnicity

    Science.gov (United States)

    Annesi, James J.; Tennant, Gisèle A.; Mareno, Nicole

    2014-01-01

    A lack of satisfaction with one's body is common among women with obesity, often prompting unhealthy "dieting." Beyond typically slow improvements in weight and body composition, behavioral factors might also affect change in body satisfaction. Age and race/ethnicity (African American vs. White) might moderate such change. Obese women (N…

  6. The effect of media analysis on attitudes and behaviors regarding body image among college students.

    Science.gov (United States)

    Rabak-Wagener, J; Eickhoff-Shemek, J; Kelly-Vance, L

    1998-07-01

    Particular strategies of media advocacy can help people contest the dominant body images of fashion advertisements and reframe them to include a broader array of "normal" images. A study with an intervention group (n = 60) and a comparison group (n = 45) of undergraduate college students was conducted to investigate whether analyzing and reframing fashion advertisements changed the students' attitudes and behaviors regarding their own body images. Results from the posttest showed a significant change in beliefs among those in the intervention group but no significant change in behaviors. The comparison group showed no significant change in beliefs or behaviors. Posttest results from the women in the intervention group (n = 44) indicated a significant change in the study participants' beliefs that adult models in advertisements have an ideal body size and shape and that the participants' decisions about dieting or exercising should be based more on looks rather than on health status.

  7. Relationship between chewing behavior and body weight status in fully dentate healthy adults.

    Science.gov (United States)

    Zhu, Yong; Hollis, James H

    2015-03-01

    Recent research indicates that chewing behavior may influence energy intake and energy expenditure. However, little is known about the relationship between chewing behavior and body weight status. In the present study, 64 fully dentate normal-weight or overweight/obese adults were asked to consume five portions of a test food and the number of chewing cycles, chewing duration before swallowing and chewing rate were measured. Adjusting for age and gender, normal-weight participants used a higher number of chewing cycles (p = 0.003) and a longer chewing duration (p chewing rate (p = 0.597). A statistically significant negative correlation between body mass index and the number of chewing cycles (r = -0.296, p = 0.020) and chewing duration (r = -0.354, p = 0.005) was observed. In conclusion, these results suggest that chewing behavior is associated with body weight status in fully dentate healthy adults.

  8. Clinical Hypnosis, an Effective Mind–Body Modality for Adolescents with Behavioral and Physical Complaints

    OpenAIRE

    Anju Sawni; Cora Collette Breuner

    2017-01-01

    Mind?body medicine is a system of health practices that includes meditation/relaxation training, guided imagery, hypnosis, biofeedback, yoga, art/music therapy, prayer, t?ai chi, and psychological therapies such as cognitive behavioral therapy. Clinical hypnosis is an important mind?body tool that serves as an adjunct to conventional medical care for the adolescent patient. Clinical hypnosis specifically uses self-directed therapeutic suggestions to cultivate the imagination and facilitate th...

  9. Cognitive-behavioral therapy for body dysmorphic disorder: a review of its efficacy

    Science.gov (United States)

    Prazeres, Angélica M; Nascimento, Antônio L; Fontenelle, Leonardo F

    2013-01-01

    The aim of this study was to review the efficacy of different methods of cognitive and/or behavioral therapies used to treat body dysmorphic disorder. We evaluated all case series, open studies, controlled trials, and meta-analyses of cognitive and/or behavioral treatment approaches to body dysmorphic disorder published up to July 2012, identified through a search in the PubMed/Medline, PsycINFO, ISI Web of Knowledge, and Scopus databases. Our findings indicate that individual and group cognitive behavioral therapies are superior to waiting list for the treatment of body dysmorphic disorder. While the efficacy of cognitive therapy is supported by one controlled trial, utility of behavioral therapy is suggested by one open study and one controlled relapse prevention follow-up study. There is a pressing need to conduct head-to-head studies, with appropriate, active, control treatment groups, in order to examine further the efficacy of cognitive and/or behavioral therapies for body dysmorphic disorder. PMID:23467711

  10. Changes in health-related behaviors and their effect on dissatisfaction with body weight in youths

    Directory of Open Access Journals (Sweden)

    Diego Augusto Santos Silva

    2014-05-01

    Full Text Available DOI: http://dx.doi.org/10.5007/1980-0037.2014v16s1p79 The aim of the present study was to establish whether changes in health related behaviors are associated with changes in the satisfaction/dissatisfaction with body weight in youths. It was a prospective study that performed a secondary analysis of data from Project “Saúde na Boa”, which included youths attending night classes in secondary public schools in Recife in the state of Pernambuco and Florianópolis in the state of Santa Catarina. Data on the youths’ body type (thinness or excess weight and degree of satisfaction/dissatisfaction with body weight and lifestyle (level of physical activity, participation in physical education classes, sedentary behavior and snacks, soda and alcohol intake were collected at 10 schools from each town (five in the intervention group and five in the control group. The percentages of youths dissatisfied with their body weight were 50.5% and 48.6% at baseline and after intervention, respectively. The percentage of youths with body dissatisfaction due to thinness decreased (21.4% vs. 16.5%, while the percentage of youths with body dissatisfaction due to excess weight increased (29.1% vs. 32.1%. Approximately 41.2% of the youths with body dissatisfaction due to thinness and 18.3% of those dissatisfied due to excess weight became satisfied with their body weight after intervention. The intervention targeting health-related behaviors induced changes in the youths’ degree of satisfaction with their body weight.

  11. Local laser-strengthening: Customizing the forming behavior of car body steel sheets

    Science.gov (United States)

    Wagner, M.; Jahn, A.; Beyer, E.; Balzani, D.

    2018-05-01

    Future trends in designing lightweight components especially for automotive applications increasingly require complex and delicate structures with highest possible level of capacity [1]. The manufacturing of metallic car body components is primarily realized by deep or stretch drawing. The forming process of especially cold rolled and large-sized components is typically characterized by inhomogeneous stress and strain distributions. As a result, the avoidance of undesirable deep drawing effects like earing and local necking is among the greatest challenges in forming complex car body structures [2]. Hence, a novel local laser-treatment approach with the objective of customizing the forming behavior of car body steel sheets is currently explored.

  12. Body weight status, eating behavior, sensitivity to reward/punishment, and gender: relationships and interdependencies

    Directory of Open Access Journals (Sweden)

    Anja eDietrich

    2014-10-01

    Full Text Available Behavioral and personality characteristics are factors that may jointly regulate body weight. This study explored the relationship between body mass index (BMI and self-reported behavioral and personality measures. These measures included eating behavior (based on the Three-Factor Eating Questionnaire- TFEQ (Stunkard and Messick, 1985, sensitivity to reward and punishment (based on the BIS/BAS Scales (Carver and White, 1994 and self-reported impulsivity (based on the Barratt Impulsiveness Scale-11 (Patton et al., 1995. We found an inverted U-shaped relationship between restrained eating and BMI. This relationship was moderated by the level of disinhibited eating. Independent of eating behavior, BIS and BAS responsiveness were associated with BMI in a gender-specific manner with negative relationships for men and positive relationships for women. Together, eating behavior and BIS/BAS responsiveness accounted for a substantial proportion of BMI variance (men: ~25%, women: ~32%. A direct relationship between self-reported impulsivity and BMI was not observed. In summary, our results demonstrate a system of linear and non-linear relationships between the investigated factors and BMI. Moreover, body weight status was not only associated with eating behavior (cognitive restraint and disinhibition, but also with personality factors not inherently related to an eating context (BIS/BAS. Importantly, these relationships differ between men and women.

  13. Associations of Anthropometric, Behavioral, and Social Factors on Level of Body Esteem in Peripubertal Girls.

    Science.gov (United States)

    Szamreta, Elizabeth A; Qin, Bo; Ohman-Strickland, Pamela A; Devine, Katie A; Stapleton, Jerod L; Ferrante, Jeanne M; Bandera, Elisa V

    2017-01-01

    Lower body esteem may decrease self-esteem and lead to adverse health effects in children. This study explored the role of anthropometric, behavioral, and social factors on body esteem in peripubertal girls. We evaluated associations of body esteem (measured by the Revised Body Esteem Scale) with body mass index (BMI), mother's BMI, puberty, physical activity, role models for appearance, and screen time among girls (ages 9 and 10) participating in the Jersey Girl Study (n = 120). Linear models were used to evaluate differences in body esteem scores. Overweight/obese girls had a significantly lower mean body esteem score compared with underweight/healthy weight girls {14.09 (95% confidence interval [CI]: 12.53-15.27) vs. 17.17 (95% CI: 16.87-17.43)}. Girls who were physically active for at least 7 hours per week had a significantly higher body esteem score than those who were less active, after adjusting for BMI (17.00 [95% CI: 16.62-17.32] vs. 16.39 [95% CI: 15.82-16.86]). Girls whose mothers were overweight/obese, who had entered puberty, and who cited girls at school or females in the media as role models had lower body esteem scores, but differences disappeared after adjusting for girl's BMI. A trend of higher body esteem scores was found for girls whose mothers were role models. Lower BMI and higher levels of physical activity are independently associated with higher body esteem score. Having classmates or girls/women in the media as role models may detrimentally affect girls' body esteem, but having mothers as role models may have a positive effect.

  14. Torsional Rigidity of Minimal Submanifolds

    DEFF Research Database (Denmark)

    Markvorsen, Steen; Palmer, Vicente

    2006-01-01

    We prove explicit upper bounds for the torsional rigidity of extrinsic domains of minimal submanifolds $P^m$ in ambient Riemannian manifolds $N^n$ with a pole $p$. The upper bounds are given in terms of the torsional rigidities of corresponding Schwarz symmetrizations of the domains in warped...

  15. Clinical Application of a Behavioral Model for the Treatment of Body Dysmorphic Disorder

    Science.gov (United States)

    Rabinowitz, Dena; Neziroglu, Fugen; Roberts, Marty

    2007-01-01

    Body dysmorphic disorder (BDD) is characterized by an obsessive concern over a perceived flaw in bodily appearance. If a minor flaw does exist, the patient displays unwarranted distress. This preoccupation typically leads to compulsive behaviors, such as mirror checking or mirror avoiding, camouflaging, and seeking reassurance from others…

  16. The Relationship between Body Dysmorphic Disorder Behaviors and the Acquired Capability for Suicide

    Science.gov (United States)

    Witte, Tracy K.; Didie, Elizabeth R.; Menard, William; Phillips, Katharine A.

    2012-01-01

    In a sample of 200 individuals diagnosed with body dysmorphic disorder (BDD), we utilized the interpersonal-psychological theory for suicide as a framework to examine BDD behaviors that might be associated with suicide risk, insofar as they might increase the acquired capability for suicide. We predicted that physically painful BDD behaviors…

  17. Body Mass Index Self-Perception and Weight Management Behaviors during Late Adolescence

    Science.gov (United States)

    Yang, Kyeongra; Turk, Melanie T.; Allison, Virginia L.; James, Khara A.; Chasens, Eileen

    2014-01-01

    Background: This study examined the relationship between actual body weight and self-perceived weight, and how perception of one's weight affects weight management behaviors among US adolescents. Methods: Adolescents ages 16-19 years with objectively-measured weight and height and self-reported perception of weight, weight-loss efforts, and…

  18. Gender differences in disordered eating behaviors and body dissatisfaction among adolescents with type 1 diabetes

    DEFF Research Database (Denmark)

    Araia, E; Hendrieckx, Christel; Skinner, Timothy

    2017-01-01

    OBJECTIVE: To examine gender differences in disordered eating behaviors (DEB) and body dissatisfaction in adolescents with type 1 diabetes. While evidence shows that female youth with type 1 diabetes are more prone to DEB compared to their peers without diabetes, little is known about male adoles...

  19. Child and Adolescent Affective and Behavioral Distress and Elevated Adult Body Mass Index

    Science.gov (United States)

    McClure, Heather H.; Eddy, J. Mark; Kjellstrand, Jean M.; Snodgrass, J. Josh; Martinez, Charles R., Jr.

    2012-01-01

    Obesity rates throughout the world have risen rapidly in recent decades, and are now a leading cause of morbidity and mortality. Several studies indicate that behavioral and affective distress in childhood may be linked to elevated adult body mass index (BMI). The present study utilizes data from a 20-year longitudinal study to examine the…

  20. High Blood Pressure in Adults with Disabilities: Influence of Gender, Body Weight and Health Behaviors

    Science.gov (United States)

    Lin, Lan-Ping; Liu, Chien-Ting; Liou, Shih-Wen; Hsu, Shang-Wei; Lin, Jin-Ding

    2012-01-01

    The aims of this study were to explore the mean and distribution of systolic and diastolic blood pressure, and to examine the influence of gender, body weight and health behaviors on hypertension in adults with disabilities. We analyzed the 2010 annual community health examination chart of adults with disabilities in east Taiwan. The study samples…

  1. Reversible Rigidity Control Using Low Melting Temperature Alloys

    Science.gov (United States)

    Shan, Wanliang; Lu, Tong; Majidi, Carmel

    2013-03-01

    Inspired by nature, materials able to achieve rapid rigidity changes have important applications for human body protection in military and many other areas. This talk presents the fabrication and design of soft-matter technologies that exhibit rapid reversible rigidity control. Fabricated with a masked deposition technique, the soft-matter composite contains liquid-phase and phase-changing metal alloys embedded in a soft and highly stretchable elastomer. The composite material can reversibly change its rigidity by three orders of magnitude and sustain large deformation.

  2. Quantum charged rigid membrane

    Energy Technology Data Exchange (ETDEWEB)

    Cordero, Ruben [Departamento de Fisica, Escuela Superior de Fisica y Matematicas del I.P.N., Unidad Adolfo Lopez Mateos, Edificio 9, 07738 Mexico, D.F. (Mexico); Molgado, Alberto [Unidad Academica de Fisica, Universidad Autonoma de Zacatecas, Zacatecas Zac. (Mexico); Rojas, Efrain, E-mail: cordero@esfm.ipn.mx, E-mail: amolgado@fisica.uaz.edu.mx, E-mail: efrojas@uv.mx [Departamento de Fisica, Facultad de Fisica e Inteligencia Artificial, Universidad Veracruzana, 91000 Xalapa, Veracruz (Mexico)

    2011-03-21

    The early Dirac proposal to model the electron as a charged membrane is reviewed. A rigidity term, instead of the natural membrane tension, involving linearly the extrinsic curvature of the worldvolume swept out by the membrane is considered in the action modeling the bubble in the presence of an electromagnetic field. We set up this model as a genuine second-order derivative theory by considering a non-trivial boundary term which plays a relevant part in our formulation. The Lagrangian in question is linear in the bubble acceleration and by means of the Ostrogradski-Hamiltonian approach, we observed that the theory comprises the management of both first- and second-class constraints. We thus show that our second-order approach is robust allowing for a proper quantization. We found an effective quantum potential which permits us to compute bounded states for the system. We comment on the possibility of describing brane world universes by invoking this kind of second-order correction terms.

  3. Quantum charged rigid membrane

    International Nuclear Information System (INIS)

    Cordero, Ruben; Molgado, Alberto; Rojas, Efrain

    2011-01-01

    The early Dirac proposal to model the electron as a charged membrane is reviewed. A rigidity term, instead of the natural membrane tension, involving linearly the extrinsic curvature of the worldvolume swept out by the membrane is considered in the action modeling the bubble in the presence of an electromagnetic field. We set up this model as a genuine second-order derivative theory by considering a non-trivial boundary term which plays a relevant part in our formulation. The Lagrangian in question is linear in the bubble acceleration and by means of the Ostrogradski-Hamiltonian approach, we observed that the theory comprises the management of both first- and second-class constraints. We thus show that our second-order approach is robust allowing for a proper quantization. We found an effective quantum potential which permits us to compute bounded states for the system. We comment on the possibility of describing brane world universes by invoking this kind of second-order correction terms.

  4. Eating behavior dimensions. Associations with energy intake and body weight. A review.

    Science.gov (United States)

    French, Simone A; Epstein, Leonard H; Jeffery, Robert W; Blundell, John E; Wardle, Jane

    2012-10-01

    The purpose of this review is to spark integrative thinking in the area of eating behaviors by critically examining research on exemplary constructs in this area. The eating behaviors food responsiveness, enjoyment of eating, satiety responsiveness, eating in the absence of hunger, reinforcing value of food, eating disinhibition and impulsivity/self-control are reviewed in relation to energy intake, body mass index and weight gain over time. Each of these constructs has been developed independently, and little research has explored the extent to which they overlap or whether they differentially predict food choices, energy intake and weight gain in the naturalistic environment. Most available data show positive cross-sectional associations with body mass index, but fewer studies report associations with energy intake or food choices. Little prospective data are available to link measures of eating behaviors with weight gain. Disinhibition has the largest and most consistent body of empirical data that link it prospectively with weight gain. An overarching conceptual model to integrate the conceptual and empirical research base for the role of eating behavior dimensions in the field of obesity research would highlight potential patterns of interaction between individual differences in eating behaviors, specific aspects of the individual's food environment and individual variation in state levels of hunger and satiety. Copyright © 2012 Elsevier Ltd. All rights reserved.

  5. Eating Behavior Dimensions: Associations With Energy Intake And Body Weight: A Review

    Science.gov (United States)

    French, Simone A.; Epstein, Leonard H; Jeffery, Robert W.; Blundell, John E.; Wardle, Jane

    2012-01-01

    The purpose of this review is to spark integrative thinking in the area of eating behaviors by critically examining research on exemplary constructs in this area. The eating behaviors food responsiveness, enjoyment of eating, satiety responsiveness, eating in the absence of hunger, reinforcing value of food, eating disinhibition and impulsivity/self-control are reviewed in relation to energy intake, body mass index and weight gain over time. Each of these constructs has been developed independently, and little research has explored the extent to which they overlap or whether they differentially predict food choices, energy intake and weight gain in the naturalistic environment. Most available data show positive cross-sectional associations with body mass index, but fewer studies report associations with energy intake or food choices. Little prospective data are available to link measures of eating behaviors with weight gain. Disinhibition has the largest and most consistent body of empirical data that link it prospectively with weight gain. An overarching conceptual model to integrate the conceptual and empirical research base for the role of eating behavior dimensions in the field of obesity research would highlight potential patterns of interaction between individual differences in eating behaviors, specific aspects of the individual’s food environment and individual variation in state levels of hunger and satiety. PMID:22796186

  6. Standard Male Body Image and its Influence on Food Values, Attitudes and Behavior in Food University

    Directory of Open Access Journals (Sweden)

    Pâmela de Souza Dias

    2016-03-01

    Full Text Available Body image corresponds to the way the individual sees his body. The beauty standards body are established from references in which illusory short fall. The great changes in recent years in markets as food and fitness show mainly focused on developing new habits for health concerns and aesthetics. This study aimed to evaluate the correlation between body image values, attitudes and dietary behavior in college men. We used a range of silhouettes adapted model Stunkard, Sorenson e Schlusinger (1983 as cited in Kety, Rowland, Sidman & Matthysse, 1983 and Lima, Orlando, Teixeira, Castro e Damasceno (2008,

  7. Rigidity of the magic pentagram game

    Science.gov (United States)

    Kalev, Amir; Miller, Carl A.

    2018-01-01

    A game is rigid if a near-optimal score guarantees, under the sole assumption of the validity of quantum mechanics, that the players are using an approximately unique quantum strategy. Rigidity has a vital role in quantum cryptography as it permits a strictly classical user to trust behavior in the quantum realm. This property can be traced back as far as 1998 (Mayers and Yao) and has been proved for multiple classes of games. In this paper we prove ridigity for the magic pentagram game, a simple binary constraint satisfaction game involving two players, five clauses and ten variables. We show that all near-optimal strategies for the pentagram game are approximately equivalent to a unique strategy involving real Pauli measurements on three maximally-entangled qubit pairs.

  8. Rigidity of the magic pentagram game.

    Science.gov (United States)

    Kalev, Amir; Miller, Carl A

    2018-01-01

    A game is rigid if a near-optimal score guarantees, under the sole assumption of the validity of quantum mechanics, that the players are using an approximately unique quantum strategy. Rigidity has a vital role in quantum cryptography as it permits a strictly classical user to trust behavior in the quantum realm. This property can be traced back as far as 1998 (Mayers and Yao) and has been proved for multiple classes of games. In this paper we prove ridigity for the magic pentagram game, a simple binary constraint satisfaction game involving two players, five clauses and ten variables. We show that all near-optimal strategies for the pentagram game are approximately equivalent to a unique strategy involving real Pauli measurements on three maximally-entangled qubit pairs.

  9. Behavioral and body size correlates of energy intake underreporting by obese and normal-weight women.

    Science.gov (United States)

    Kretsch, M J; Fong, A K; Green, M W

    1999-03-01

    To examine behavioral and body size influences on the underreporting of energy intake by obese and normal-weight women. Seven-day estimated food records were kept by subjects before they participated in a 49-day residential study. Self-reported energy intake was compared with energy intake required to maintain a stable body weight during the residential study (reference standard). Energy intake bias and its relationship to various body size and behavioral measures were examined. Twenty-two, healthy, normal-weight (mean body mass index [BMI] = 21.3) and obese (mean BMI = 34.2) women aged 22 to 42 years were studied. Analysis of variance, paired t test, simple linear regression, and Pearson correlation analyses were conducted. Mean energy intake from self-reported food records was underreported by normal-weight (-9.7%) and obese (-19.4%) women. BMI correlated inversely with the energy intake difference for normal-weight women (r = -.67, P = .02), whereas the Beck Depression Inventory correlated positively with the energy intake difference for obese women (r = .73, P behavioral traits play a role in the ability of women to accurately self-report energy intake. BMI appears to be predictive of underreporting of energy intake by normal-weight women, whereas emotional factors related to depression appear to be more determinant of underreporting for obese women. Understanding causative factors of the underreporting phenomenon will help practicing dietitians to devise appropriate and realistic diet intervention plans that clients can follow to achieve meaningful change.

  10. Eating behaviors, body image, perfectionism, and self-esteem in a sample of Portuguese girls

    Directory of Open Access Journals (Sweden)

    Maria D. Teixeira

    2016-01-01

    Full Text Available Objective: Eating disorders are an increasingly prevalent health problem among adolescent girls. It is well known that biological, psychosocial, and family-related factors interact in the development of this group of disorders. However, the mechanisms underlying the interaction between these variables are still poorly understood, especially in Portuguese adolescents. The aim of this study was to investigate the relationship between eating behaviors, body dissatisfaction, self-esteem, and perfectionism in a sample of Portuguese girls. Method: A community sample of 575 Portuguese girls attending secondary school, answered self-report questionnaires including data on weight, height, and the Portuguese versions of the Contour Figures Rating Scale, the Child and Adolescent Perfectionism Scale, the Children Eating Attitudes Test, and the Rosenberg Self-Esteem Scale. SPSS version 20.0 for Windows was used for statistical analyses. Results: High scores in the Children Eating Attitudes Test were associated with significantly higher levels of body dissatisfaction (r = 0.339, socially prescribed perfectionism (r = 0.175, self-oriented perfectionism (r = 0.211, and low self-esteem (r = -0.292 (all p < 0.001. Self-oriented perfectionism partially mediated the relation between body dissatisfaction and disordered eating behaviors. Conclusion: In this sample, dysfunctional eating behaviors appeared to correlate strongly with body dissatisfaction, low self-esteem, and perfectionism in girls. These themes should be addressed among female adolescents in the community.

  11. A role for the adult fat body in Drosophila male courtship behavior.

    Directory of Open Access Journals (Sweden)

    Anna A Lazareva

    2007-01-01

    Full Text Available Mating behavior in Drosophila depends critically on the sexual identity of specific regions in the brain, but several studies have identified courtship genes that express products only outside the nervous system. Although these genes are each active in a variety of non-neuronal cell types, they are all prominently expressed in the adult fat body, suggesting an important role for this tissue in behavior. To test its role in male courtship, fat body was feminized using the highly specific Larval serum protein promoter. We report here that the specific feminization of this tissue strongly reduces the competence of males to perform courtship. This effect is limited to the fat body of sexually mature adults as the feminization of larval fat body that normally persists in young adults does not affect mating. We propose that feminization of fat body affects the synthesis of male-specific secreted circulating proteins that influence the central nervous system. In support of this idea, we demonstrate that Takeout, a protein known to influence mating, is present in the hemolymph of adult males but not females and acts as a secreted protein.

  12. Associations Among Work and Family Health Climate, Health Behaviors, Work Schedule, and Body Weight.

    Science.gov (United States)

    Buden, Jennifer C; Dugan, Alicia G; Faghri, Pouran D; Huedo-Medina, Tania B; Namazi, Sara; Cherniack, Martin G

    2017-06-01

    Correctional employees exhibit elevated obesity rates. This study examines interrelations among health behaviors, health climate, body mass index (BMI), and work schedule. Using survey results from correctional supervisors (n = 157), mediation and moderated-mediation analyses were performed to examine how health behaviors explain relationships between obesity, work health climate (WHC) and family health climate (FHC), and work schedule. Over 85% of the sample was overweight/obese (mean BMI = 30.20). Higher WHC and FHC were associated with lower BMI, mediated by nutrition, and physical activity. The interaction effect between health behavior and work schedule revealed a protective effect on BMI. Overtime shift work may share a relationship with BMI. Findings may have implications for reexamining organizational policies on maximum weekly overtime in corrections. They provide direction for targeted obesity interventions that encourage a supportive FHC and promote healthy behaviors among supervisors working overtime.

  13. Influences of immunocontraception on time budgets, social behavior, and body condition in feral horses

    Science.gov (United States)

    Ransom, J.I.; Cade, B.S.; Hobbs, N.T.

    2010-01-01

    Managers concerned with shrinking habitats and limited resources for wildlife seek effective tools for limiting population growth in some species. Fertility control is one such tool, yet little is known about its impacts on the behavioral ecology of wild, free-roaming animals. We investigated influences of the immunocontraceptive porcine zona pellucida (PZP) on individual and social behavior in bands of feral horses (Equus caballus) in three discrete populations and used 14 hierarchical mixed effect models to gain insight into the influences of PZP treatment on feral horse behavior. A model of body condition was the strongest predictor of feeding, resting, maintenance, and social behaviors, with treated females allocating their time similarly to control females. Time spent feeding declined 11.4% from low condition to high condition females (F1,154 = 26.427, P modifications in feral horses.

  14. Quetiapine effective in treatment of inappropriate sexual behavior of lewy body disease with predominant frontal lobe signs.

    Science.gov (United States)

    Prakash, Ravi; Pathak, Amit; Munda, Sanjay; Bagati, Dhruv

    2009-01-01

    Dementia of Lewy body disease is the second most common degenerative cause of dementia after Alzheimer's disease, among all the dementias. The core features are a progressive dementia, fluctuations in cognitive functions, visual hallucinations, and spontaneous parkinsonism. Rapid eye movement sleep behavior disorder, severe neuroleptic sensitivity, and low dopamine transporter uptake in basal ganglia are other suggestive features. Behavioral abnormalities are commonly present in the form of aggressive behavior, irritability, and uninhibited behaviors. These are mostly seen in the advanced stages of dementia. However, inappropriate sexual behavior is uncommonly seen in such cases. Three types of inappropriate sexual behaviors commonly found in cases of dementia are sex talks, sexual acts, and implied sexual acts. Such inappropriate sexual behaviors have not been described adequately in dementia of Lewy body disease. We report inappropriate sexual behaviors in a case of dementia of Lewy body disease, which improved rapidly after treatment with quetiapine.

  15. On flexible and rigid nouns

    DEFF Research Database (Denmark)

    Rijkhoff, Jan

    2010-01-01

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

  16. Body image disturbance in binge eating disorder: a comparison of obese patients with and without binge eating disorder regarding the cognitive, behavioral and perceptual component of body image.

    Science.gov (United States)

    Lewer, Merle; Nasrawi, Nadia; Schroeder, Dorothea; Vocks, Silja

    2016-03-01

    Whereas the manifestation of body image disturbance in binge eating disorder (BED) has been intensively investigated concerning the cognitive-affective component, with regard to the behavioral and the perceptual components of body image disturbance in BED, research is limited and results are inconsistent. Therefore, the present study assessed body image disturbance in BED with respect to the different components of body image in a sample of obese females (n = 31) with BED compared to obese females without an eating disorder (n = 28). The Eating Disorder Inventory-2, the Eating Disorder Examination-Questionnaire, the Body Image Avoidance Questionnaire and the Body Checking Questionnaire as well as a Digital Photo Distortion Technique based on a picture of each participant taken under standardized conditions were employed. Using two-sample t tests, we found that the participants with BED displayed significantly greater impairments concerning the cognitive-affective component of body image than the control group. Concerning the behavioral component, participants with BED reported more body checking and avoidance behavior than the controls, but group differences failed to reach significance after the Bonferroni corrections. Regarding the perceptual component, a significant group difference was found for the perceived "ideal" figure, with the individuals suffering from BED displaying a greater wish for a slimmer ideal figure than the control group. These results support the assumption that body image disturbance is a relevant factor in BED, similar to other eating disorders.

  17. The Effects of Gender and Family, Friend, and Media Influences on Eating Behaviors and Body Image during Adolescence

    Science.gov (United States)

    Ata, Rheanna N.; Ludden, Alison Bryant; Lally, Megan M.

    2007-01-01

    The current study expands upon body image research to examine how gender, self-esteem, social support, teasing, and family, friend, and media pressures relate to body image and eating-related attitudes and behaviors among male and female adolescents (N = 177). Results indicated that adolescents were dissatisfied with their current bodies: males…

  18. Body Satisfaction and Eating Disorder Behaviors among Immigrant Adolescents in North America

    Science.gov (United States)

    Magtoto, Joanne; Cox, David; Saewyc, Elizabeth

    2013-01-01

    Using a province-wide school-based health survey, this article investigated body satisfaction as a mediator of the association between eating disorder behaviors and immigrant status. Participants were a sample of adolescent girls (n = 15,066) and boys (n = 14,200) who completed the 2008 McCreary Centre Society Adolescent Health Survey IV.…

  19. Agreement Between Actual and Perceived Body Weight in Adolescents and Their Weight Control Behaviors

    Directory of Open Access Journals (Sweden)

    Sun Mi Shin

    2017-06-01

    Full Text Available Background : To investigate the agreements between actual and perceived body weight status among adolescents and to identify the associations of disagreements with their weight control behaviors. Methods : This study used the secondary data of a sample survey (n=13,871 of the Seoul Student Health Examination among middle and high schools in 2010. Agreements between actual (underweight, normal, overweight, and obese, according to 2007 Korean National Growth Charts and perceived body weight status (underweight, normal, overweight, and obese were examined using Chi-square and Cohen’s kappa agreement, and then multinomial logistic regression including gender, grade, and attempt of weight control or method of weight control was done. Results : Agreements between actual and perceived body weight status were only 45.2%, and disagreements were up to 54.8%, including mild over- (20.4%, severe over- (1.8%, mild under- (29.5%, and severe under-estimation (3.1%. The kappa coefficient of agreement was only 0.19. The odds ratios on severe over-estimated perception were 1.59 (95% CI, 1.22-2.07 in female subjects, 1.78 (95% CI, 1.36-2.34 in diet control behaviors, and 1.53 (95% CI, 1.18-2.00 in exercise. The odds ratios on severe under-estimated perception were only 0.40 (95% CI, 0.32–0.50 in female subjects but 5.77 (95% CI, 3.68-9.06 in taking medication. Conclusion : There were associations of body weight control behaviors with disagreements of actual and perceived weight status. Therefore, further study is needed to identify the weight disagreement-related factors and to promote the desired weight control behaviors for adolescents.

  20. Effect of three-body forces on the phase behavior of charged colloids

    International Nuclear Information System (INIS)

    Wu, J. Z.; Bratko, D.; Blanch, H. W.; Prausnitz, J. M.

    2000-01-01

    Statistical-thermodynamic theory for predicting the phase behavior of a colloidal solution requires the pair interaction potential between colloidal particles in solution. In practice, it is necessary to assume pairwise additivity for the potential of mean force between colloidal particles, but little is known concerning the validity of this assumption. This paper concerns interaction between small charged colloids, such as surfactant micelles or globular proteins, in electrolyte solutions and the multibody effect on phase behavior. Monte Carlo simulations for isolated colloidal triplets in equilateral configurations show that, while the three-body force is repulsive when the three particles are near contact, it becomes short-ranged attractive at further separations, contrary to a previous study where the triplet force is attractive at all separations. The three-body force arises mainly from hard-sphere collisions between colloids and small ions; it is most significant in solutions of monovalent salt at low concentration where charged colloids experience strong electrostatic interactions. To illustrate the effect of three-body forces on the phase behavior of charged colloids, we calculated the densities of coexisting phases using van der Waals-type theories for colloidal solutions and for crystals. For the conditions investigated in this work, even though the magnitude of the three-body force may be as large as 10% of the total force at small separations, three-body forces do not have a major effect on the densities of binary coexisting phases. However, coexisting densities calculated using Derjaguin-Landau-Verwey-Overbeek theory are much different from those calculated using our simulated potential of mean force. (c) 2000 American Institute of Physics

  1. Attitudes to body weight, weight gain and eating behavior in pregnancy.

    Science.gov (United States)

    Abraham, S; King, W; Llewellyn-Jones, D

    1994-12-01

    The eating behavior and attitudes to body weight of 100 healthy women were studied 3 days after the birth of their first child. During pregnancy women 'watch their weight' and use a range of methods of weight control which include cigarette smoking and inducing vomiting. During pregnancy 41 women reported weight control problems and 20 women considered their weight and eating problems to be greater than at any previous time. Picking was the most common unwanted behavior. Binge eating was experienced by 44 women, nine of whom reported it to be a 'severe' problem. Although women were ambivalent about being weighed at each antenatal visit, 81 recommended weighing once each month. The women held differing opinions on the effects of breastfeeding on body weight and on the need for nutritional supplements during pregnancy. Women reporting 'disordered eating' were more likely to have antenatal complications and give birth to low birthweight babies. The results suggest good obstetric care should include a history of the woman's eating behavior and body weight.

  2. Dopamine and Mushroom Bodies in Drosophila: Experience-Dependent and -Independent Aspects of Sexual Behavior

    Science.gov (United States)

    Neckameyer, Wendi S.

    1998-01-01

    Depletion of dopamine in Drosophila melanogaster adult males, accomplished through systemic introduction of the tyrosine hydroxylase inhibitor 3-iodo-tyrosine, severely impaired the ability of these flies to modify their courtship responses to immature males. Mature males, when first exposed to immature males, will perform courtship rituals; the intensity and duration of this behavior rapidly diminshes with time. Dopamine is also required for normal female sexual receptivity; dopamine-depleted females show increased latency to copulation. One kilobase of 5′ upstream information from the Drosophila tyrosine hydroxylase (DTH) gene, when fused to the Escherichia coli β-galactosidase reporter and transduced into the genome of Drosophila melanogaster, is capable of directing expression of the reporter gene in the mushroom bodies, which are believed to mediate learning acquisition and memory retention in flies. Ablation of mushroom bodies by treatment of newly hatched larva with hydroxyurea resulted in the inability of treated mature adult males to cease courtship when placed with untreated immature males. However, functional mushroom bodies were not required for the dopaminergic modulation of an innate behavior, female sexual receptivity. These data suggest that dopamine acts as a signaling molecule within the mushroom bodies to mediate a simple form of learning. PMID:10454380

  3. Geographical variation in sexual behavior and body traits in a sex role reversed wolf spider

    Science.gov (United States)

    Bollatti, Fedra; Diaz, Virginia Garcia; Peretti, Alfredo V.; Aisenberg, Anita

    2017-06-01

    Mating partners need to recognize, assess each other, and exchange information through behavioral events that occur before, during, and after mating. Sexual signals, as well as life history traits, are influenced by selective pressures and environmental factors that can vary across distant geographical areas. Allocosa senex is a sand-dwelling wolf spider which constructs burrows along the sandy coasts of Argentina, Brazil, and Uruguay. Females are the mobile sex that searches for males and initiates courtship. They prefer males which construct longer burrows, and males prefer virgin females in good body condition. The objective of this study was to compare sexual behavior patterns, as well as body characteristics and burrow dimensions, between two geographically distant locations of A. senex, one in Uruguay (Uruguayan location) and the other from central Argentina (Argentinean location). We found differences in the number of male abdominal vibrations, male and female touches during mating, and number of erections of male leg spines, which all were higher in matings of Argentinean pairs. On the other hand, male body mass and female body condition were higher in Uruguayan individuals. The wide distribution of A. senex could be determining variations in the biotic and abiotic features that affect the species, generating differences in the strength of selective forces acting on individuals from the two studied locations.

  4. Eating behavior and body image perception of pregnant women attending a high-risk outpatient center

    Directory of Open Access Journals (Sweden)

    Raquel Guimarães Nobre

    2014-06-01

    Full Text Available Objective: To investigate the eating behavior and body image perception in pregnant women attending a high-risk outpatient center. Methods: A quantitative, cross-sectional, observational study conducted with 28 overweight pregnant women attending the first consultation in the nutrition outpatient center of a maternity hospital in Fortaleza-CE, from December 2010 to February 2011. It has been used a pre-established form containing data on the characterization of the sample (socioeconomic, obstetric, and nutritional, the BES (Binge Eating Scale to assess binge eating and BSQ (Body Shape Questionnaire to assess the severity or absence of body image disorder. The variables were presented as mean ± standard deviation and simple frequency and percentage. The Pearson’s correlation was used to verify the relation between body image and binge eating, considering p <0.05. Results: The pregnant women studied had a mean age of 29.4 ± 6.3 years and mean gestational age of 24.6 ± 8.2 weeks. It was found a prevalence of 71.5% (n=20 of body image disorder and 17.8% (n=5 of binge eating. It was also observed a direct and significant correlation between the body image perception and the degree of binge eating (r=0.4358, p=0.020. Conclusion: The high rate of body image disorder positively related to a significant binge eating indicates an unfavorable adjustment of this group of pregnant women to alterations in weight and body shape and size, which are inherent to pregnancy, standing out as group that needs special attention by the professional team. doi:10.5020/18061230.2014.p256

  5. [The relationship between adolescent body size and health promoting behavior and biochemical indicator factors].

    Science.gov (United States)

    Chen, Hsiu-Chih; Chen, Hsing-Mei; Chen, Min-Li; Chiang, Chih-Ming; Chen, Mei-Yen

    2012-06-01

    Tainan City has the third highest prevalence of junior high school student obesity of all administrative districts in Taiwan. School nurses play an important role in promoting student health. Understanding the factors that significantly impact student weight is critical to designing effective student health promotion programs. This study explored the relationships between health promotion behavior and serum biomarker variables and body size. Researchers used a cross-sectional descriptive study design and stratified cluster random sampling. Subjects were 7th graders who received an in-school health checkup with blood test at 41 public junior high schools in Tainan City between July 2010 and May 2011. Research instruments included the adolescent health promotion (AHP) scale, serum biochemical profile and BMI (body mass index). Obtained data were analyzed using descriptive and inferential statistics. Of the 726 students who participated in this study, 22.2% were underweight and 23.8% were overweight or obese. Higher AHP scores correlated with better biomarkers and body size. Multivariate analysis found factors that increased the risk of being overweight included: being male, having a father with a relatively low level of education, playing video games frequently, and doing little or no exercise (odds ratio = 1.93, 1.75, 1.07, 1.04, respectively). Participants with relatively healthy behaviors had better biomarkers and a lower risk of being overweight. Findings can support the development of evidence-based school programs to promote student health.

  6. [Muscle dysmorphia, body image and eating behaviors in two male populations].

    Science.gov (United States)

    Behar, Rosa; Molinari, Daniela

    2010-11-01

    Muscle dysmorphia or vigorexia is a disorder in which a person becomes obsessed with the idea that he or she is not muscular enough. To assess physical exercise, eating behaviors and the presence of muscle dysmorphia among weightlifters and medical students. Cross sectional evaluation of 88 male weightlifters aged 27 ± 7 years and 84 male medical students aged 22 ± 1 year was made. Eating behaviors were evaluated using the Eating Attitudes Test (EAT-40) and the Eating Disorders Inventory (EDI). The perception of body image was assessed using the Graduate Hannover Scale (GHS). Prevalence of muscle dysmorphia among weightlifters was 13.6%. Both groups did not differ in body dissatisfaction. Interest in appearance among weightlifters was significantly higher than in students and ranged significantly higher in EAT-40 and EDI (p < 0.001). Other sports were practiced with the same frequency by weightlifters and students. Weightlifters expended more time than students exercising to improve their appearance (p < 0.005). Forty two percent of weightlifters with muscle dysmorphia displayed abuse of anabolics and 67% used other substances to improve their performance (p < 0.005). The presence of muscle dysmorphia among weightlifters was confirmed. They were dissatisfied with their body image and more concerned with their physical appearance than those without muscle dysmorphia and/or students. Their anabolic abuse rate was high. Our findings were similar to those reported in the international literature.

  7. Healthy food consumption in young women. The influence of others' eating behavior and body weight appearance.

    Science.gov (United States)

    Stel, Mariëlle; van Koningsbruggen, Guido M

    2015-07-01

    People's eating behaviors tend to be influenced by the behaviors of others. In the present studies, we investigated the effect of another person's eating behavior and body weight appearance on healthy food consumption of young women. In Study 1, participants watched a short film fragment together with a confederate who appeared normal weight or overweight and consumed either 3 or 10 cucumber slices. In Study 2, a confederate who appeared underweight, normal weight, or overweight consumed no or 4 cucumber slices. The number of cucumber slices eaten by participants was registered. Results showed that participants' healthy eating behavior was influenced by the confederate's eating behavior when the confederate was underweight, normal weight, and overweight. Participants ate more cucumber slices when the confederate ate a higher amount of cucumber slices compared with a lower (or no) amount of cucumber slices (Studies 1 and 2). The food intake effect was stronger for the underweight compared with the overweight model (Study 2). Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Dieting behaviors, body shape perceptions, and body satisfaction: cross-cultural differences in Argentinean and Swedish 13-year-olds.

    Science.gov (United States)

    Holmqvist, Kristina; Lunde, Carolina; Frisén, Ann

    2007-06-01

    This exploratory study represents a cross-cultural effort to examine differences in dieting practices and weight loss attempts, perceived body shape, and body satisfaction between young Argentinean and Swedish adolescents. The study group consisted of 358 Argentinean (193 girls, 165 boys) and 874 Swedish (474 girls, 400 boys) 13-year-olds. A main finding was that Argentinean and Swedish adolescents did not differ on body satisfaction, although girls in both countries displayed greater body dissatisfaction than did boys. Dieting and weight loss attempts were more prevalent among the Argentinean adolescents, especially among girls, and did not appear to depend on overweight or perception of body shape. The samples also differed in their perceptions of body shape and the effect those perceptions had on their body satisfaction, with Swedish adolescents suffering more from negative body shape perceptions.

  9. Insulin-like peptide genes in honey bee fat body respond differently to manipulation of social behavioral physiology.

    Science.gov (United States)

    Nilsen, Kari-Anne; Ihle, Kate E; Frederick, Katy; Fondrk, M Kim; Smedal, Bente; Hartfelder, Klaus; Amdam, Gro V

    2011-05-01

    Nutrient sensitive insulin-like peptides (ILPs) have profound effects on invertebrate metabolism, nutrient storage, fertility and aging. Many insects transcribe ILPs in specialized neurosecretory cells at changing levels correlated with life history. However, the major site of insect metabolism and nutrient storage is not the brain, but rather the fat body, where functions of ILP expression are rarely studied and poorly understood. Fat body is analogous to mammalian liver and adipose tissue, with nutrient stores that often correlate with behavior. We used the honey bee (Apis mellifera), an insect with complex behavior, to test whether ILP genes in fat body respond to experimentally induced changes of behavioral physiology. Honey bee fat body influences endocrine state and behavior by secreting the yolk protein precursor vitellogenin (Vg), which suppresses lipophilic juvenile hormone and social foraging behavior. In a two-factorial experiment, we used RNA interference (RNAi)-mediated vg gene knockdown and amino acid nutrient enrichment of hemolymph (blood) to perturb this regulatory module. We document factor-specific changes in fat body ilp1 and ilp2 mRNA, the bee's ILP-encoding genes, and confirm that our protocol affects social behavior. We show that ilp1 and ilp2 are regulated independently and differently and diverge in their specific expression-localization between fat body oenocyte and trophocyte cells. Insect ilp functions may be better understood by broadening research to account for expression in fat body and not only brain.

  10. Rigidly foldable origami gadgets and tessellations

    Science.gov (United States)

    Evans, Thomas A.; Lang, Robert J.; Magleby, Spencer P.; Howell, Larry L.

    2015-01-01

    Rigidly foldable origami allows for motion where all deflection occurs at the crease lines and facilitates the application of origami in materials other than paper. In this paper, we use a recently discovered method for determining rigid foldability to identify existing flat-foldable rigidly foldable tessellations, which are also categorized. We introduce rigidly foldable origami gadgets which may be used to modify existing tessellations or to create new tessellations. Several modified and new rigidly foldable tessellations are presented. PMID:26473037

  11. The influence of materialism and ideal body internalization on body-dissatisfaction and body-shaping behaviors of young men and women: support for the Consumer Culture Impact Model.

    Science.gov (United States)

    Guðnadóttir, Unnur; Garðarsdóttir, Ragna B

    2014-04-01

    Exposure to media images of the 'body-perfect' ideal has been partly blamed for the pursuit of thinness among women and muscularity among men. Research has largely overlooked the materialistic messages frequently associated with these images. We present findings from two studies with Icelandic students aged 18-21, one focusing on young women (n = 303) and one on young men (n = 226), which test associations of materialistic and body-perfect ideals with body dissatisfaction and excessive body shaping behaviors. In both studies, the internalization of materialistic values is strongly linked to the internalization of body-perfect ideals: the thin-ideal for young women, and the muscular-ideal for young men. A materialist value orientation also predicted body dissatisfaction in both studies, and was linked to body shaping behaviors, albeit differently for young women and men. Thus, the research identifies materialism as a further correlate of both body dissatisfaction and excessive body-shaping behaviors. The findings support Dittmar's (2008) Consumer Culture Impact Model, which proposes that the body-perfect and 'material good life' ideals jointly impact well-being. © 2014 Scandinavian Psychological Associations and John Wiley & Sons Ltd.

  12. Body imaging and sexual behavior in lean women with polycystic ovary syndrome.

    Science.gov (United States)

    Morotti, Elena; Persico, Nicola; Battaglia, Bruno; Fabbri, Raffaella; Meriggiola, Maria Cristina; Venturoli, Stefano; Battaglia, Cesare

    2013-11-01

    In women with polycystic ovary syndrome (PCOS), changes in body appearance may influence the feminine identity of the patients with possible consequent depression and sexual dysfunction. The study aims to examine the differences in mood, perceived body image, sexual behavior, and clitoral vascularization between lean PCOS patients and healthy eumenorrheic controls. Thirty-three lean PCOS women (Group I) and 22 healthy nonhirsute volunteers (Group II) were submitted, on day 3-5 of the cycle, to ultrasonographic (US) and Doppler analyses, to clinical, hormonal, and biochemical evaluations, and to psychometric tests. Main outcome measures are Ferriman-Gallwey score (FG), clitoral volume, clitoral artery Pulsatility Index, the two-factor Italian McCoy female questionnaire (MFSQ), the Stunkard Figure Rating Scale (FRS), and the Beck Depression Inventory (BDI) questionnaire. The FG score and the androgens resulted, as expected, more elevated in PCOS patients than in controls. However, the US assessment of the clitoral body volume and the resistances registered at the level of the dorsal clitoral artery did not show any difference between Group I and Group II patients. Moreover, the two-factor Italian MFSQ, the FRS, and the BDI were similar in both groups. It seems that in lean PCOS women, the moderate hirsutism and hyperandrogenism do not have any important influence on body image and self-esteem and, as a consequence, on sexual function. © 2013 International Society for Sexual Medicine.

  13. SPH for impact force and ricochet behavior of water-entry bodies

    Science.gov (United States)

    Omidvar, Pourya; Farghadani, Omid; Nikeghbali, Pooyan

    The numerical modeling of fluid interaction with a bouncing body has many applications in scientific and engineering application. In this paper, the problem of water impact of a body on free-surface is investigated, where the fixed ghost boundary condition is added to the open source code SPHysics2D1 to rectify the oscillations in pressure distributions with the repulsive boundary condition. First, after introducing the methodology of SPH and the option of boundary conditions, the still water problem is simulated using two types of boundary conditions. It is shown that the fixed ghost boundary condition gives a better result for a hydrostatics pressure. Then, the dam-break problem, which is a bench mark test case in SPH, is simulated and compared with available data. In order to show the behavior of the hydrostatics forces on bodies, a fix/floating cylinder is placed on free surface looking carefully at the force and heaving profile. Finally, the impact of a body on free-surface is successfully simulated for different impact angles and velocities.

  14. Subcutaneous body lipids affect cyclicity and estrus behavior in primiparous Charolais cows.

    Science.gov (United States)

    Recoules, E; De La Torre, A; Agabriel, J; Egal, D; Blanc, F

    2013-08-01

    Conception rate and the calving interval of beef cows are known to be influenced by body reserves at calving and subsequent postpartum changes. However, few studies have focused on the effect of body reserve dynamics on both postpartum cyclicity and estrus expression. Two successive similar experiments (Year 1: n=14; Year 2: n=16) were carried out on primiparous Charolais cows reared indoors during winter to quantify the effects of adipose cell diameter at calving (ACDca) and their postpartum changes (ACDch) on cyclicity and estrus behavior. Cows were managed to calve with a body condition score (BCS, scale 0-5) of 2.5 (Year 1) and 1.5 (Year 2). After calving cows were assigned to a Low vs. a High energy level diet until turn out to pasture in May. Within years ACDca was similar between Low and High groups whereas calving to turnout changes of body weight (BW), BCS and adipose cell diameter differed (Pbody lipids to predict relationships between nutrition and reproduction in cows. Copyright © 2013 Elsevier B.V. All rights reserved.

  15. Clinical Hypnosis, an Effective Mind-Body Modality for Adolescents with Behavioral and Physical Complaints.

    Science.gov (United States)

    Sawni, Anju; Breuner, Cora Collette

    2017-03-24

    Mind-body medicine is a system of health practices that includes meditation/relaxation training, guided imagery, hypnosis, biofeedback, yoga, art/music therapy, prayer, t'ai chi, and psychological therapies such as cognitive behavioral therapy. Clinical hypnosis is an important mind-body tool that serves as an adjunct to conventional medical care for the adolescent patient. Clinical hypnosis specifically uses self-directed therapeutic suggestions to cultivate the imagination and facilitate the mind-body connection, leading to positive emotional and physical well-being. There are many similarities between clinical hypnosis and other mind-body/self-regulatory modalities such as visual imagery, mindfulness meditation, yoga, and biofeedback that incorporate experiential learning and mechanisms for change. They may be viewed as subtypes of the hypnotic experience and share the common experience of trance as the entrée into self-empowered change in physiologic and psychological states. Clinical hypnosis can be used by health care providers to teach adolescents coping skills to deal with a wide variety of conditions such as chronic headaches, recurrent abdominal pain, anxiety, depression, grief and bereavement, phobias, anger, family stressors, sleep disorders, or enuresis. Clinical vignettes are given to help illustrate the effectiveness of hypnosis in adolescents.

  16. Clinical Hypnosis, an Effective Mind–Body Modality for Adolescents with Behavioral and Physical Complaints

    Science.gov (United States)

    Sawni, Anju; Breuner, Cora Collette

    2017-01-01

    Mind–body medicine is a system of health practices that includes meditation/relaxation training, guided imagery, hypnosis, biofeedback, yoga, art/music therapy, prayer, t’ai chi, and psychological therapies such as cognitive behavioral therapy. Clinical hypnosis is an important mind–body tool that serves as an adjunct to conventional medical care for the adolescent patient. Clinical hypnosis specifically uses self-directed therapeutic suggestions to cultivate the imagination and facilitate the mind–body connection, leading to positive emotional and physical well-being. There are many similarities between clinical hypnosis and other mind–body/self-regulatory modalities such as visual imagery, mindfulness meditation, yoga, and biofeedback that incorporate experiential learning and mechanisms for change. They may be viewed as subtypes of the hypnotic experience and share the common experience of trance as the entrée into self-empowered change in physiologic and psychological states. Clinical hypnosis can be used by health care providers to teach adolescents coping skills to deal with a wide variety of conditions such as chronic headaches, recurrent abdominal pain, anxiety, depression, grief and bereavement, phobias, anger, family stressors, sleep disorders, or enuresis. Clinical vignettes are given to help illustrate the effectiveness of hypnosis in adolescents. PMID:28338644

  17. Clinical Hypnosis, an Effective Mind–Body Modality for Adolescents with Behavioral and Physical Complaints

    Directory of Open Access Journals (Sweden)

    Anju Sawni

    2017-03-01

    Full Text Available Mind–body medicine is a system of health practices that includes meditation/relaxation training, guided imagery, hypnosis, biofeedback, yoga, art/music therapy, prayer, t’ai chi, and psychological therapies such as cognitive behavioral therapy. Clinical hypnosis is an important mind–body tool that serves as an adjunct to conventional medical care for the adolescent patient. Clinical hypnosis specifically uses self-directed therapeutic suggestions to cultivate the imagination and facilitate the mind–body connection, leading to positive emotional and physical well-being. There are many similarities between clinical hypnosis and other mind–body/self-regulatory modalities such as visual imagery, mindfulness meditation, yoga, and biofeedback that incorporate experiential learning and mechanisms for change. They may be viewed as subtypes of the hypnotic experience and share the common experience of trance as the entrée into self-empowered change in physiologic and psychological states. Clinical hypnosis can be used by health care providers to teach adolescents coping skills to deal with a wide variety of conditions such as chronic headaches, recurrent abdominal pain, anxiety, depression, grief and bereavement, phobias, anger, family stressors, sleep disorders, or enuresis. Clinical vignettes are given to help illustrate the effectiveness of hypnosis in adolescents.

  18. Not only body weight perception but also body mass index is relevant to suicidal ideation and self-harming behavior in Japanese adolescents.

    Science.gov (United States)

    Kinoshita, Kuni; Kinoshita, Yoshihiro; Shimodera, Shinji; Nishida, Atsushi; Inoue, Ken; Watanabe, Norio; Oshima, Norihito; Akechi, Tatsuo; Sasaki, Tsukasa; Inoue, Shimpei; Furukawa, Toshiaki A; Okazaki, Yuji

    2012-04-01

    Whether a low body mass index (BMI) is directly associated with a high risk of suicidal ideation or self-harming behavior in adolescents is still inconclusive. This study has, therefore, evaluated the relevance of BMI to suicidal ideation and self-harming behavior after controlling for body weight perception (BWP) and other potential confounding factors. BMI, BWP, suicidal ideation, and self-harming behavior were all assessed using a self-report questionnaire administered to 18,104 Japanese adolescents. Potential confounding factors were also evaluated. The data were then analyzed using bivariate and multivariate logistic regression. Low BMI was associated with suicidal ideation and deliberate self-harm when controlling for sex, age, drug use, emotional distress, and BWP. Low BMI may be an independent risk factor for suicidal ideation and deliberate self-harming behavior in Japanese adolescents.

  19. Did Immanuel Kant have dementia with Lewy bodies and REM behavior disorder?

    Science.gov (United States)

    Miranda, Marcelo; Slachevsky, Andrea; Garcia-Borreguero, Diego

    2010-06-01

    Immanuel Kant, one of the most brilliant minds of the XVIII century and of western philosophy, suffered from dementia in his late years. Based on the analysis of testimonies of his close friends, in this report we describe his neurological disorder which, after 8years of evolution, led to his death. His cognitive decline was strongly associated with a parasomnia compatible with a severe rapid eye movement (REM) behavior disorder (RBD) and dementia with Lewy bodies. Copyright 2010 Elsevier B.V. All rights reserved.

  20. The Feeding Behavior and Dissatisfaction With Body Image of Female Basketball Athletes' A City Central São Paulo

    Directory of Open Access Journals (Sweden)

    Micheli Bordonal Gazolla

    2015-12-01

    Full Text Available The most important eating disorders are anorexia and bulimia nervosa. This study intended to appraise athletes' behavior related to food , weight control and body image. The obtained results were: 25% present light distortions of their body image and 16,66% show moderate distortions. Based on the silhouettes of Stunkard et al., 66,66% overestimate their weight, 16,66% show dissatisfaction in relation to their thinness, 16,67% are pleased with their body weight. The majority of the athletes presents proper body composition, but presents a distortion of their body image.

  1. Gender differences in body composition, physical activity, eating behavior and body image among normal weight adolescents--an evolutionary approach.

    Science.gov (United States)

    Kirchengast, Sylvia; Marosi, Andrea

    2008-12-01

    Body composition but also physical activity patterns underlie gender typical differences throughout human life. In the present study the body composition of 354 girls and 280 boys ageing between 11 and 18 years originating from Eastern Austria were analyzed using bioelectrical impedance method. Normal weight according to body mass index categories was a strict inclusion criterion. Information regarding physical activity during school and leisure time, daily nutritional habits, subjective body satisfaction and weight control practices were collected by means of a structured and standardized questionnaire. Results of the analyses reveal that--as to be expected--adolescent boys and girls differed significantly in body composition, but also in physical activity patterns. Even normal weight girls exhibited a significantly higher amount of absolute and relative fat mass, whereas normal weight boys showed a significantly higher amount of fat free body mass. Furthermore male adolescents were significantly more physically active than their female counterparts. According to the results of multiple regression analyses physical activity patterns had beside sex an independent influence on body composition parameters during adolescence. In contrast, girls and boys showed only minor differences in nutritional habits and weight control practices. Nutritional habits, body satisfaction and weight control practices were not significantly related to body composition parameters. The observed gender differences in body composition as well as in physical activity patterns are interpreted in an evolutionary sense.

  2. Drosophila mushroom bodies integrate hunger and satiety signals to control innate food-seeking behavior.

    Science.gov (United States)

    Tsao, Chang-Hui; Chen, Chien-Chun; Lin, Chen-Han; Yang, Hao-Yu; Lin, Suewei

    2018-03-16

    The fruit fly can evaluate its energy state and decide whether to pursue food-related cues. Here, we reveal that the mushroom body (MB) integrates hunger and satiety signals to control food-seeking behavior. We have discovered five pathways in the MB essential for hungry flies to locate and approach food. Blocking the MB-intrinsic Kenyon cells (KCs) and the MB output neurons (MBONs) in these pathways impairs food-seeking behavior. Starvation bi-directionally modulates MBON responses to a food odor, suggesting that hunger and satiety controls occur at the KC-to-MBON synapses. These controls are mediated by six types of dopaminergic neurons (DANs). By manipulating these DANs, we could inhibit food-seeking behavior in hungry flies or promote food seeking in fed flies. Finally, we show that the DANs potentially receive multiple inputs of hunger and satiety signals. This work demonstrates an information-rich central circuit in the fly brain that controls hunger-driven food-seeking behavior. © 2018, Tsao et al.

  3. Rigidity-tuning conductive elastomer

    Science.gov (United States)

    Shan, Wanliang; Diller, Stuart; Tutcuoglu, Abbas; Majidi, Carmel

    2015-06-01

    We introduce a conductive propylene-based elastomer (cPBE) that rapidly and reversibly changes its mechanical rigidity when powered with electrical current. The elastomer is rigid in its natural state, with an elastic (Young’s) modulus of 175.5 MPa, and softens when electrically activated. By embedding the cPBE in an electrically insulating sheet of polydimethylsiloxane (PDMS), we create a cPBE-PDMS composite that can reversibly change its tensile modulus between 37 and 1.5 MPa. The rigidity change takes ˜6 s and is initiated when a 100 V voltage drop is applied across the two ends of the cPBE film. This magnitude of change in elastic rigidity is similar to that observed in natural skeletal muscle and catch connective tissue. We characterize the tunable load-bearing capability of the cPBE-PDMS composite with a motorized tensile test and deadweight experiment. Lastly, we demonstrate the ability to control the routing of internal forces by embedding several cPBE-PDMS ‘active tendons’ into a soft robotic pneumatic bending actuator. Selectively activating the artificial tendons controls the neutral axis and direction of bending during inflation.

  4. Rigidity-tuning conductive elastomer

    International Nuclear Information System (INIS)

    Shan, Wanliang; Diller, Stuart; Tutcuoglu, Abbas; Majidi, Carmel

    2015-01-01

    We introduce a conductive propylene-based elastomer (cPBE) that rapidly and reversibly changes its mechanical rigidity when powered with electrical current. The elastomer is rigid in its natural state, with an elastic (Young’s) modulus of 175.5 MPa, and softens when electrically activated. By embedding the cPBE in an electrically insulating sheet of polydimethylsiloxane (PDMS), we create a cPBE–PDMS composite that can reversibly change its tensile modulus between 37 and 1.5 MPa. The rigidity change takes ∼6 s and is initiated when a 100 V voltage drop is applied across the two ends of the cPBE film. This magnitude of change in elastic rigidity is similar to that observed in natural skeletal muscle and catch connective tissue. We characterize the tunable load-bearing capability of the cPBE–PDMS composite with a motorized tensile test and deadweight experiment. Lastly, we demonstrate the ability to control the routing of internal forces by embedding several cPBE–PDMS ‘active tendons’ into a soft robotic pneumatic bending actuator. Selectively activating the artificial tendons controls the neutral axis and direction of bending during inflation. (paper)

  5. Body Image, Self-Esteem, and Health-Related Behaviors among Male and Female First Year College Students

    Science.gov (United States)

    Lowery, Sarah E.; Kurpius, Sharon E. Robinson; Befort, Christie; Blanks, Elva Hull; Sollenberger, Sonja; Nicpon, Megan Foley; Huser, Laura

    2005-01-01

    This study examined the relationships among self-esteem, body image, and health-related behaviors of 267 female and 156 male first-year college students. Data were collected in 23 classrooms. Instruments included a demographic sheet, the Objectified Body Consciousness Scale, the Weight and Appearance Visual Analogue Scales, the Contour Drawing…

  6. Cohort Removal Induces Changes in Body Temperature, Pain Sensitivity, and Anxiety-Like Behavior

    Science.gov (United States)

    Takao, Keizo; Shoji, Hirotaka; Hattori, Satoko; Miyakawa, Tsuyoshi

    2016-01-01

    Mouse behavior is analyzed to elucidate the effects of various experimental manipulations, including gene mutation and drug administration. When the effect of a factor of interest is assessed, other factors, such as age, sex, temperature, apparatus, and housing, are controlled in experiments by matching, counterbalancing, and/or randomizing. One such factor that has not attracted much attention is the effect of sequential removal of animals from a common cage (cohort removal). Here we evaluated the effects of cohort removal on rectal temperature, pain sensitivity, and anxiety-like behavior by analyzing the combined data of a large number of C57BL/6J mice that we collected using a comprehensive behavioral test battery. Rectal temperature increased in a stepwise manner according to the position of sequential removal from the cage, consistent with previous reports. In the hot plate test, the mice that were removed first from the cage had a significantly longer latency to show the first paw response than the mice removed later. In the elevated plus maze, the mice removed first spent significantly less time on the open arms compared to the mice removed later. The results of the present study demonstrated that cohort removal induces changes in body temperature, pain sensitivity, and anxiety-like behavior in mice. Cohort removal also increased the plasma corticosterone concentration in mice. Thus, the ordinal position in the sequence of removal from the cage should be carefully counterbalanced between groups when the effect of experimental manipulations, including gene manipulation and drug administration, are examined using behavioral tests. PMID:27375443

  7. Cohort removal induces changes in body temperature, pain sensitivity, and anxiety-like behavior

    Directory of Open Access Journals (Sweden)

    Keizo eTakao

    2016-06-01

    Full Text Available Mouse behavior is analyzed to elucidate the effects of various experimental manipulations, including gene mutation and drug administration. When the effect of a factor of interest is assessed, other factors, such as age, sex, temperature, apparatus, and housing, are controlled in experiments by matching, counterbalancing, and/or randomizing. One such factor that has not attracted much attention is the effect of sequential removal of animals from a common cage (cohort removal. Here we evaluated the effects of cohort removal on rectal temperature, pain sensitivity, and anxiety-like behavior by analyzing the combined data of a large number of C57BL/6J mice that we collected using a comprehensive behavioral test battery. Rectal temperature increased in a stepwise manner according to the position of sequential removal from the cage, consistent with previous reports. In the hot plate test, the mice that were removed first from the cage had a significantly longer latency to show the first paw response than the mice removed later. In the elevated plus maze, the mice removed first spent significantly less time on the open arms compared to the mice removed later. The results of the present study demonstrated that cohort removal induces changes in body temperature, pain sensitivity, and anxiety-like behavior in mice. Cohort removal also increased the plasma corticosterone concentration in mice. Thus, the ordinal position in the sequence of removal from the cage should be carefully counterbalanced between groups when the effect of experimental manipulations, including gene manipulation and drug administration, are examined using behavioral tests.

  8. Mid-Lift-to-Drag Ratio Rigid Vehicle Control System Design and Simulation for Human Mars Entry

    Science.gov (United States)

    Johnson, Breanna J.; Cerimele, Christopher J.; Stachowiak, Susan J.; Sostaric, Ronald R.; Matz, Daniel A.; Lu, Ping

    2018-01-01

    The Mid-Lift-to-Drag Ratio Rigid Vehicle (MRV) is a proposed candidate in the NASA Evolvable Mars Campaign's (EMC) Pathfinder Entry, Descent, and Landing (EDL) architecture study. The purpose of the study is to design a mission and vehicle capable of transporting a 20mt payload to the surface of Mars. The MRV is unique in its rigid, asymmetrical lifting-body shape which enables a higher lift-to-drag ratio (L/D) than the typical robotic Mars entry capsule vehicles that carry much less mass. This paper presents the formulation and six-degree-of-freedom (6DOF) performance of the MRV's control system, which uses both aerosurfaces and a propulsive reaction control system (RCS) to affect longitudinal and lateral directional behavior.

  9. Mind magic: a pilot study of preventive mind-body-based stress reduction in behaviorally inhibited and activated children

    NARCIS (Netherlands)

    Jellesma, F.C.; Cornelis, J.

    2012-01-01

    Purpose of study: The aim of this pilot study was to examine a mind-body-based preventive intervention program and to determine relationships between children's behavioral inhibition system (BIS) and behavioral activation system, stress, and stress reduction after the program. Design of study:

  10. The body composition, nutritional knowledge, attitudes, behaviors, and future education needs of senior schoolboy rugby players in Ireland.

    Science.gov (United States)

    Walsh, Michelle; Cartwright, Laura; Corish, Clare; Sugrue, Sheila; Wood-Martin, Ruth

    2011-10-01

    This study examined the body composition, nutritional knowledge, behaviors, attitudes, and educational needs of senior schoolboy rugby players in Ireland. Participants included 203 male rugby players age 15-18 yr competing at Senior School's Cup level in Leinster, Ireland. Estimation of body composition included measurement of height, weight, and percentage body fat (PBF; using bioelectrical impedance analysis, Tanita BC-418). Nutritional knowledge, behaviors, attitudes, and education needs were assessed by questionnaire. The range of PBF was 5.1-25.3%. Sixty-eight percent of the players in this study had a healthy PBF (10-20%), 32 (22%) were classified as underweight (benefit from appropriate nutritional education.

  11. Behavioral and environmental modification of the genetic influence on body mass index: A twin study

    Science.gov (United States)

    Horn, Erin E.; Turkheimer, Eric; Strachan, Eric; Duncan, Glen E.

    2015-01-01

    Body mass index (BMI) has a strong genetic basis, with a heritability around 0.75, but is also influenced by numerous behavioral and environmental factors. Aspects of the built environment (e.g., environmental walkability) are hypothesized to influence obesity by directly affecting BMI, by facilitating or inhibiting behaviors such as physical activity that are related to BMI, or by suppressing genetic tendencies toward higher BMI. The present study investigated relative influences of physical activity and walkability on variance in BMI using 5,079 same-sex adult twin pairs (70% monozygotic, 65% female). High activity and walkability levels independently suppressed genetic variance in BMI. Estimating their effects simultaneously, however, suggested that the walkability effect was mediated by activity. The suppressive effect of activity on variance in BMI was present even with a tendency for low-BMI individuals to select into environments that require higher activity levels. Overall, our results point to community- or macro-level interventions that facilitate individual-level behaviors as a plausible approach to addressing the obesity epidemic among U.S. adults. PMID:25894925

  12. Mineralization behavior and interface properties of BG-PVA/bone composite implants in simulated body fluid.

    Science.gov (United States)

    Ma, Yanxuan; Zheng, Yudong; Huang, Xiaoshan; Xi, Tingfei; Lin, Xiaodan; Han, Dongfei; Song, Wenhui

    2010-04-01

    Due to the non-bioactivity and poor conjunction performance of present cartilage prostheses, the main work here is to develop the bioactive glass-polyvinyl alcohol hydrogel articular cartilage/bone (BG-PVA/bone) composite implants. The essential criterion for a biomaterial to bond with living bone is well-matched mechanical properties as well as biocompatibility and bioactivity. In vitro studies on the formation of a surface layer of carbonate hydroxyl apatite (HCA) and the corresponding variation of the properties of biomaterials are imperative for their clinical application. In this paper, the mineralization behavior and variation of the interface properties of BG-PVA/bone composites were studied in vitro by using simulated body fluid (SBF). The mineralization and HCA layer formed on the interface between the BG-PVA hydrogel and bone in SBF could provide the composites with bioactivity and firmer combination. The compression property, shear strength and interface morphology of BG-PVA/bone composite implants varying with the immersion time in SBF were characterized. Also, the influence laws of the immersion time, content of BG in the composites and aperture of bones to the mineralization behavior and interface properties were investigated. The good mineralization behavior and enhanced conjunction performance of BG-PVA/bone composites demonstrated that this kind of composite implant might be more appropriate cartilage replacements.

  13. Mineralization behavior and interface properties of BG-PVA/bone composite implants in simulated body fluid

    Energy Technology Data Exchange (ETDEWEB)

    Ma Yanxuan; Zheng Yudong; Huang Xiaoshan; Xi Tingfei; Han Dongfei [School of Materials Science and Engineering, Beijing University of Science and Technology, Beijing 100083 (China); Lin Xiaodan [College of Materials Science and Engineering, South China University of Technology, Guangzhou 510640 (China); Song Wenhui, E-mail: zhengyudong@mater.ustb.edu.c, E-mail: wenhui.song@brunel.ac.u [Wolfson Center for Materials Processing, School of Engineering and Design, Brunel University, West London, UB8 3PH (United Kingdom)

    2010-04-15

    Due to the non-bioactivity and poor conjunction performance of present cartilage prostheses, the main work here is to develop the bioactive glass-polyvinyl alcohol hydrogel articular cartilage/bone (BG-PVA/bone) composite implants. The essential criterion for a biomaterial to bond with living bone is well-matched mechanical properties as well as biocompatibility and bioactivity. In vitro studies on the formation of a surface layer of carbonate hydroxyl apatite (HCA) and the corresponding variation of the properties of biomaterials are imperative for their clinical application. In this paper, the mineralization behavior and variation of the interface properties of BG-PVA/bone composites were studied in vitro by using simulated body fluid (SBF). The mineralization and HCA layer formed on the interface between the BG-PVA hydrogel and bone in SBF could provide the composites with bioactivity and firmer combination. The compression property, shear strength and interface morphology of BG-PVA/bone composite implants varying with the immersion time in SBF were characterized. Also, the influence laws of the immersion time, content of BG in the composites and aperture of bones to the mineralization behavior and interface properties were investigated. The good mineralization behavior and enhanced conjunction performance of BG-PVA/bone composites demonstrated that this kind of composite implant might be more appropriate cartilage replacements.

  14. Gender differences in physical activity, sedentary behavior, and their relation to body composition in active Brazilian adolescents.

    Science.gov (United States)

    Nogueira, Julia Aparecida Devide; Macedo da Costa, Teresa Helena

    2009-01-01

    Body weight and composition are determined by genotype, environment, and energy balance. Physical activity or sedentary behavior have different associations with body weight, fat mass, and fat-free mass, a relationship that is not clear in adolescents. The aim of this study was to test the associations between gender, physical activity, sedentary behavior, and body composition in physically active adolescents. Weight, height, and skinfold thickness were measured in 326 physically active boys and girls age 11 to 15 years. All subjects answered a questionnaire assessing their usual daily activities for the last month. Time spent on each activity was used to estimate the physical activity level (PAL). PAL was associated with body composition after adjustment for age and maturation, with differences between genders. For boys, PAL was positively and significantly associated with body mass index (BMI) and fat-free mass index (beta=0.14 and 0.15, respectively). For girls, PAL was negatively and significantly associated with BMI and fat mass index (beta=-0.11 and -0.75, respectively). Sedentary behavior, expressed by hours of TV, videogame, and computer use, was not associated with any body-composition outcome for either gender. The accumulated amount of physical activity, but not of sedentary behavior, was related to body composition in active adolescents.

  15. On flexible and rigid nouns

    DEFF Research Database (Denmark)

    Rijkhoff, Jan

    2008-01-01

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

  16. Functionally rigid bistable [2]rotaxanes

    DEFF Research Database (Denmark)

    Nygaard, Sune; Leung, Ken C-F; Aprahamian, Ivan

    2007-01-01

    defines an unambiguous distance of 1.5 nm over which the ring moves between the MPTTF and NP units. The degenerate NP/NP [2]rotaxane was used to investigate the shuttling barrier by dynamic 1H NMR spectroscopy for the movement of the CBPQT4+ ring across the new rigid spacer. It is evident from...... better control over the position of the ring component in the ground state but also for control over the location of the CBPQT4+ ring during solution-state switching experiments, triggered either chemically (1H NMR) or electrochemically (cyclic voltammetry). In this instance, the use of the rigid spacer......Two-station [2]rotaxanes in the shape of a degenerate naphthalene (NP) shuttle and a nondegenerate monopyrrolotetrathiafulvalene (MPTTF)/NP redox-controllable switch have been synthesized and characterized in solution. Their dumbbell-shaped components are composed of polyether chains interrupted...

  17. Rigidity spectrum of Forbush decrease

    International Nuclear Information System (INIS)

    Sakakibara, S.; Munakata, K.; Nagashima, K.

    1985-01-01

    Using data from neutron monitors and muon telescopes at surface and underground stations, the average rigidity spectrum of Forbush decreases (Fds) during the period of 1978-1982 were obtained. Thirty eight Ed-events are classified into two groups, Hard Fd and Soft FD according to size of Fd at the Sakashita station. It is found that a spectral form of a fractional-power type (P to the-gamma sub 1 (P+P sub c) to the -gamma sub2) is more suitable than that of a power-exponential type or of a power type with an upper limiting rigidity. The best fitted spectrum of the fractional-power type is expressed by gamma sub1 = 0.37, gamma sub2 = 0.89 and P subc = 10 GV for Hard Fd and gamma sub1 = 0.77, gamma sub2 = 1.02 and P sub c - 14GV for Soft Fd

  18. Signature of Thermal Rigidity Percolation

    International Nuclear Information System (INIS)

    Huerta, Adrián

    2013-01-01

    To explore the role that temperature and percolation of rigidity play in determining the macroscopic properties, we propose a model that adds translational degrees of freedom to the spins of the well known Ising hamiltonian. In particular, the Ising model illustrate the longstanding idea that the growth of correlations on approach to a critical point could be describable in terms of the percolation of some sort of p hysical cluster . For certain parameters of this model we observe two well defined peaks of C V , that suggest the existence of two kinds of p hysical percolation , namely connectivity and rigidity percolation. Thermal fluctuations give rise to two different kinds of elementary excitations, i.e. droplets and configuron, as suggested by Angell in the framework of a bond lattice model approach. The later is reflected in the fluctuations of redundant constraints that gives stability to the structure and correlate with the order parameter

  19. Torsional rigidity, isospectrality and quantum graphs

    International Nuclear Information System (INIS)

    Colladay, Don; McDonald, Patrick; Kaganovskiy, Leon

    2017-01-01

    We study torsional rigidity for graph and quantum graph analogs of well-known pairs of isospectral non-isometric planar domains. We prove that such isospectral pairs are distinguished by torsional rigidity. (paper)

  20. Dietary behaviors and body image recognition of college students according to the self-rated health condition.

    Science.gov (United States)

    Kim, Mi Joung; Lim, Ye Rom; Kwak, Ho Kyung

    2008-01-01

    This study was done to investigate the relationship between the perception of body image, body weight satisfaction or dietary behavior and self-rated health status in Korean college students. Subjects, 285 college students, were divided into three groups (healthy, normal, and unhealthy) according to the answer for the self-rated health question. Information about demographic status, self-rated health condition, height and weight, perception of body image, satisfaction of body weight, concern for body weight control, dietary behavior, nutritional knowledge, and health-related characteristics collected by a self-reported questionnaire. The proportion of men and women in each group was not significantly different. The academic year, major, experience of nutritional education, and type of residence were not significantly related with self-rated health but the pocket money range was significantly associated (ppocket money range and was increased in less than 210 thousand won or over 300 thousand won pocket money ranges. There were no significant differences for age, height, weight and BMI between the groups. The body image perception and body weight satisfaction levels of healthy group was significantly higher than those of unhealthy group (p<0.01 and p<0.001, respectively), but the level of concern for body weight control in healthy subjects was significantly lower than that in unhealthy subjects (p<0.05). The proportion of subjects reported as healthy was significantly increased with increased frequencies of following food behaviors; weekly use of protein foods (p<0.01), vegetables (p<0.05) and dairy products (p<0.01), and food habits such as "regularity of meal time" (p<0.01), "eating in moderation" (p<0.05), and "eating breakfast" (p<0.001). Overall results suggested that the college students have tended to have a better perception of health when they have better body image perception, body weight satisfaction and dietary behaviors.

  1. Management of rigid post-traumatic kyphosis.

    Science.gov (United States)

    Wu, S S; Hwa, S Y; Lin, L C; Pai, W M; Chen, P Q; Au, M K

    1996-10-01

    Rigid post-traumatic kyphosis after fracture of the thoracolumbar and lumbar spine represents a failure of initial management of the injury. Kyphosis moves the center of gravity anterior. The kyphosis and instability may result in pain, deformity, and increased neurologic deficits. Management for symptomatic post-traumatic kyphosis always has presented a challenge to orthopedic surgeons. To evaluate the surgical results of one stage posterior correction for rigid symptomatic post-traumatic kyphosis of the thoracolumbar and lumbar spine. The management for post-traumatic kyphosis remains controversial. Anterior, posterior, or combined anterior and posterior procedures have been advocated by different authors and show various degrees of success. One vertebra immediately above and below the level of the deformity was instrumented posteriorly by a transpedicular system (internal fixator AO). Posterior decompression was performed by excision of the spinal process and bilateral laminectomy. With the deformed vertebra through the pedicle, the vertebral body carefully is removed around the pedicle level, approximating a wedge shape. The extent to which the deformed vertebral body should be removed is determined by the attempted correction. Correction of the deformity is achieved by manipulation of the operating table and compression of the adjacent Schanz screws above and below the lesion. Thirteen patients with post-traumatic kyphosis with symptoms of fatigue and pain caused by slow progression of kyphotic deformities received posterior decompression, correction, and stabilization as a definitive treatment. The precorrection kyphosis ranged from 30-60 degrees, with a mean of 40 degrees +/- 10.8 degrees. After correction, kyphosis was reduced to an average of 1.5 degrees +/- 3.8 degrees, with a range from -5 degrees to 5 degrees. The average angle of correction was 38.8 degrees +/- 10.4 degrees, with a range from 25 degrees to 60 degrees. Significant difference was found

  2. Biodegradable behaviors of AZ31 magnesium alloy in simulated body fluid

    International Nuclear Information System (INIS)

    Song Yingwei; Shan Dayong; Chen Rongshi; Zhang Fan; Han Enhou

    2009-01-01

    Magnesium alloys have unique advantages to act as biodegradable implants for clinical application. The biodegradable behaviors of AZ31 in simulated body fluid (SBF) for various immersion time intervals were investigated by electrochemical impedance spectroscopy (EIS) tests and scanning electron microscope (SEM) observation, and then the biodegradable mechanisms were discussed. It was found that a protective film layer was formed on the surface of AZ31 in SBF. With increasing of immersion time, the film layer became more compact. If the immersion time was more than 24 h, the film layer began to degenerate and emerge corrosion pits. In the meantime, there was hydroxyapatite particles deposited on the film layer. The hydroxyapatite is the essential component of human bone, which indicates the perfect biocompatibility of AZ31 magnesium alloy.

  3. Rigidity of monodromies for Appell's hypergeometric functions

    Directory of Open Access Journals (Sweden)

    Yoshishige Haraoka

    2015-01-01

    Full Text Available For monodromy representations of holonomic systems, the rigidity can be defined. We examine the rigidity of the monodromy representations for Appell's hypergeometric functions, and get the representations explicitly. The results show how the topology of the singular locus and the spectral types of the local monodromies work for the study of the rigidity.

  4. Body image and self-esteem among adolescents undergoing an intervention targeting dietary and physical activity behaviors.

    Science.gov (United States)

    Huang, Jeannie S; Norman, Gregory J; Zabinski, Marion F; Calfas, Karen; Patrick, Kevin

    2007-03-01

    To determine the effect of a one-year intervention targeting physical activity, sedentary, and diet behaviors among adolescents on self-reported body image and self-esteem. Health promotion interventions can lead to awareness of health risk and subsequent adoption of beneficial changes in behavior. However, it is possible that interventions targeting behaviors associated with childhood obesity may also increase the likelihood of unhealthy eating and physical activity obsessions and behaviors. Body image and self-esteem were assessed for adolescents participating in the PACE+ study, a randomized controlled trial of a 1-year behavioral intervention targeting physical activity, sedentary, and dietary behaviors. The Body Dissatisfaction subscale of the Eating Disorder Inventory and Rosenberg Self-Esteem scale were used to assess body image and self-esteem, respectively, and measurements were performed at baseline, and at 6 and 12 months. Demographic characteristics and weight status of participants were also ascertained. Analysis of responses was performed via both between-group and within-group repeated measure analyses. There were 657 adolescents who completed all measurements. Body image differences were found for age, gender, and weight status at baseline, whereas self-esteem differences were demonstrated for gender, ethnicity, and weight status. There were no intervention effects on body image or self-esteem for either girls or boys. Self-esteem and body satisfaction did not worsen as a result of participating in the PACE+ intervention for either boys or girls whether or not they lost or maintained their weight or gained weight. Girls assigned to the PACE intervention who experienced weight reduction or weight maintenance at either 6 or 12 months reported improvements in body image satisfaction (p = .02) over time compared with subjects who had experienced weight gain during the 12-month study period. Adverse effects on body satisfaction and self-esteem were not

  5. Objectively-determined intensity- and domain-specific physical activity and sedentary behavior in relation to percent body fat.

    Science.gov (United States)

    Scheers, Tineke; Philippaerts, Renaat; Lefevre, Johan

    2013-12-01

    This study examined the independent and joint associations of overall, intensity-specific and domain-specific physical activity and sedentary behavior with bioelectrical impedance-determined percent body fat. Physical activity was measured in 442 Flemish adults (41.4 ± 9.8 years) using the SenseWear Armband and an electronic diary. Two-way analyses of covariance investigated the interaction of physical activity and sedentary behavior with percent body fat. Multiple linear regression analyses, adjusted for potential confounders, examined the associations of intensity-specific and domain-specific physical activity and sedentary behavior with percent body fat. Results showed a significant main effect for physical activity in both genders and for sedentary behavior in women, but no interaction effects. Light activity was positively (β = 0.41 for men and 0.43 for women) and moderate (β = -0.64 and -0.41), vigorous (β = -0.21 and -0.24) and moderate-to-vigorous physical activity (MVPA) inversely associated with percent body fat, independent of sedentary time. Regarding domain-specific physical activity, significant associations were present for occupation, leisure time and household chores, irrespective of sedentary time. The positive associations between body fat and total and domain-specific sedentary behavior diminished after MVPA was controlled for. MVPA during leisure time, occupation and household chores may be essential to prevent fat gain. Copyright © 2013 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

  6. The effect of active video gaming on children's physical activity, behavior preferences and body composition.

    Science.gov (United States)

    Graves, Lee E F; Ridgers, Nicola D; Atkinson, Greg; Stratton, Gareth

    2010-11-01

    Active video game interventions typically provide children a single game that may become unappealing. A peripheral device (jOG) encourages step-powered gaming on multiple games. This trial evaluated the effect of jOG on children's objectively measured PA, body fat and self-reported behaviors. 42 of 58 eligible children (8-10 y) randomly assigned to an intervention (jOG) or control (CON) completed the trial. Intervention children received two jOG devices for home use. Analyses of covariance compared the intervention effect at 6 and 12 weeks from baseline. No differences were found between groups for counts per minute (CPM; primary outcome) at 6 and 12 weeks (p > .05). Active video gaming increased (adjusted change 0.95 (95% CI 0.25, 1.65) h·d⁻¹, p video gaming decreased (-0.34 (-1.24, 0.56) h·d⁻¹, p > .05) at 6 weeks relative to CON. No body fat changes were observed between groups. Targeted changes in video game use did not positively affect PA. Larger trials are needed to verify the impact of active video games on children's PA and health.

  7. Eating behaviors, body image, perfectionism, and self-esteem in a sample of Portuguese girls.

    Science.gov (United States)

    Teixeira, Maria D; Pereira, Ana T; Marques, Mariana V; Saraiva, Jorge M; Macedo, António F de

    2016-02-05

    Eating disorders are an increasingly prevalent health problem among adolescent girls. It is well known that biological, psychosocial, and family-related factors interact in the development of this group of disorders. However, the mechanisms underlying the interaction between these variables are still poorly understood, especially in Portuguese adolescents. The aim of this study was to investigate the relationship between eating behaviors, body dissatisfaction, self-esteem, and perfectionism in a sample of Portuguese girls. A community sample of 575 Portuguese girls attending secondary school, answered self-report questionnaires including data on weight, height, and the Portuguese versions of the Contour Figures Rating Scale, the Child and Adolescent Perfectionism Scale, the Children Eating Attitudes Test, and the Rosenberg Self-Esteem Scale. SPSS version 20.0 for Windows was used for statistical analyses. High scores in the Children Eating Attitudes Test were associated with significantly higher levels of body dissatisfaction (r = 0.339), socially prescribed perfectionism (r = 0.175), self-oriented perfectionism (r = 0.211), and low self-esteem (r = -0.292) (all p self-esteem, and perfectionism in girls. These themes should be addressed among female adolescents in the community.

  8. Static friction between rigid fractal surfaces.

    Science.gov (United States)

    Alonso-Marroquin, Fernando; Huang, Pengyu; Hanaor, Dorian A H; Flores-Johnson, E A; Proust, Gwénaëlle; Gan, Yixiang; Shen, Luming

    2015-09-01

    Using spheropolygon-based simulations and contact slope analysis, we investigate the effects of surface topography and atomic scale friction on the macroscopically observed friction between rigid blocks with fractal surface structures. From our mathematical derivation, the angle of macroscopic friction is the result of the sum of the angle of atomic friction and the slope angle between the contact surfaces. The latter is obtained from the determination of all possible contact slopes between the two surface profiles through an alternative signature function. Our theory is validated through numerical simulations of spheropolygons with fractal Koch surfaces and is applied to the description of frictional properties of Weierstrass-Mandelbrot surfaces. The agreement between simulations and theory suggests that for interpreting macroscopic frictional behavior, the descriptors of surface morphology should be defined from the signature function rather than from the slopes of the contacting surfaces.

  9. Unified Creep Plasticity Damage (UCPD) Model for Rigid Polyurethane Foams.

    Energy Technology Data Exchange (ETDEWEB)

    Neilsen, Michael K. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lu, Wei-Yang [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Scherzinger, William M. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hinnerichs, Terry D. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Lo, Chi S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-06-01

    Numerous experiments were performed to characterize the mechanical response of several different rigid polyurethane foams (FR3712, PMDI10, PMDI20, and TufFoam35) to large deformation. In these experiments, the effects of load path, loading rate, and temperature were investigated. Results from these experiments indicated that rigid polyurethane foams exhibit significant volumetric and deviatoric plasticity when they are compressed. Rigid polyurethane foams were also found to be very strain-rate and temperature dependent. These foams are also rather brittle and crack when loaded to small strains in tension or to larger strains in compression. Thus, a new Unified Creep Plasticity Damage (UCPD) model was developed and implemented into SIERRA with the name Foam Damage to describe the mechanical response of these foams to large deformation at a variety of temperatures and strain rates. This report includes a description of recent experiments and experimental findings. Next, development of a UCPD model for rigid, polyurethane foams is described. Selection of material parameters for a variety of rigid polyurethane foams is then discussed and finite element simulations with the new UCPD model are compared with experimental results to show behavior that can be captured with this model.

  10. Associations among health behaviors, body mass index, hypertension, and diabetes mellitus: A path analysis.

    Science.gov (United States)

    Min, Deulle; Cho, Eunhee

    2018-06-01

    Hypertension (HTN) and type 2 diabetes are common diseases; however, the effects of health behavior and body mass index (BMI) on their incidence and relationship are unclear. The purpose of this study was to investigate the associations among health behaviors, BMI, HTN, and type 2 diabetes.This study was a secondary data analysis using Korean Longitudinal Study of Aging data between 2010 and 2014 (third and fifth). The sample consisted of 3481 people aged 45 years or older. Path analysis was conducted using the generalized structural equation modeling of STATA 13.1 that enabled analyzing the types of binary variables and logit links.There were 129 underweight, 1714 normal, and 1638 overweight and obese individuals. In underweight and normal groups who had regular meals (B = 0.670, P diabetes increased with age (B = 0.051, P = .005) and smoking (B = 1.539, P = .001). However, the incidence of type 2 diabetes was lower (B = -1.077, P = .036) for those who had regular meals. In the normal and overweight groups, BMI decreased with age (B = -0.033, P diabetes increased with age (B = 0.046, P diabetes. Smoking has a direct effect on the incidence of type 2 diabetes. Thus, the importance of maintaining an ideal BMI and smoking cessation are highlighted.

  11. The influence of a behavior modification interventional program on body mass index in obese adolescents.

    Science.gov (United States)

    Toulabi, Tahereh; Khosh Niyat Nikoo, Mohsen; Amini, Fariba; Nazari, Hedayat; Mardani, Mahnaz

    2012-03-01

    The prevalence of obesity and overweight among children and adolescents is increasing rapidly. The present research was performed to determine the influence of a ''behavior modification'' program on body mass index (BMI) in obese public high school students in Iran. In this study, 152 adolescence and their parents were selected from 12 high schools of Khorram Abad from 2004 to 2006, and they were randomly assigned to either the intervention or the control groups. The "behavior modification" interventional program consisted of nutritional education, modifying dietary habits, teaching exercise programs, teaching nutritional facts to the parents, and performing exercises 3 days a week. The height and weight as well as waist, hip, and wrist circumferences of the participants were measured before and after implementing the interventional program. BMI and waist to hip ratio (WHR) were calculated. The adolescents and parents completed a nutrition knowledge questionnaire. Adolescents also completed the Beck's Depression Questionnaire. Adolescent's mean weight, BMI, and waist and hip circumferences decreased significantly after implementing the interventional program, in the intervention group (p≤0.001). In addition, the students' and parents' nutrition knowledge increased in the intervention group after implementing the interventional program (pbehavior modification'' interventional program is effective in reducing BMI in obese students, and therefore, school principals and planners can play an important role in controlling obesity by implementing this program via the students, their parents, and the school staff. Copyright © 2012. Published by Elsevier B.V.

  12. Degradation behavior of hydroxyapatite/poly(lactic-co-glycolic) acid nanocomposite in simulated body fluid

    International Nuclear Information System (INIS)

    Liuyun, Jiang; Chengdong, Xiong; Lixin, Jiang; Lijuan, Xu

    2013-01-01

    Graphical abstract: In this manuscript, we initiated a systematic study to investigate the effect of HA on thermal properties, inner structure, reduction of mechanical strength, surface morphology and the surface deposit of n-HA/PLGA composite with respect to the soaking time. The results showed that n-HA played an important role in improving the degradation behavior of n-HA/PLGA composite, which can accelerate the degradation of n-HA/PLGA composite and endow it with bioactivity, after n-HA was detached from PLGA during the degradation, so that n-HA/PLGA composite may have a more promising prospect of the clinical application than pure PLGA as bone fracture internal fixation materials, and the results would be of reference significance to predict the in vivo degradation and biological properties. - Highlights: • Effect of n-HA on degradation behavior of n-HA/PLGA composite was investigated. • Degradation behaviors of n-HA/PLGA and PLGA were carried out in SBF for 6 months. • Viscosity, thermal properties, inner structure and bending strength were tested. • n-HA can accelerate the degradation and endows it with bioactivity. - Abstract: To investigate the effect of hydroxyapatite(HA) on the degradation behavior of hydroxyapatite/poly(lactic-co-glycolic) acid (HA/PLGA) nanocomposite, the degradation experiment of n-HA/PLGA composite and pure PLGA were carried out by soaking in simulated body fluid(SBF) at 37 °C for 1, 2, 4 and 6 months. The change of intrinsic viscosity, thermal properties, inner structure, bending strength reduction, surface morphology and the surface deposit of n-HA/PLGA composite and pure PLGA with respect to the soaking time were investigated by means of UbbeloHde Viscometer, differential scanning calorimeter (DSC), scanning electron microscope(SEM), electromechanical universal tester, a conventional camera and X-ray diffraction (XRD). The results showed that n-HA played an important role in improving the degradation behavior of n

  13. Targeting impulsive processes of eating behavior via the internet. Effects on body weight.

    Science.gov (United States)

    Veling, Harm; van Koningsbruggen, Guido M; Aarts, Henk; Stroebe, Wolfgang

    2014-07-01

    Because eating behavior can take on an impulsive nature many people experience difficulty with dieting to lose weight. Therefore, an experiment was conducted to test the effectiveness of two interventions targeting impulsive processes of eating behavior to facilitate weight loss: Implementation intentions to remind people about dieting versus a go/no-go task to change impulses toward palatable foods. Dieters performed an online training program (four times in 4 weeks) in which they were randomly assigned to a 2 (implementation intention condition: dieting versus control) × 2 (go/no-go task condition: food versus control) design. They formed either dieting implementation intentions (e.g., If I open the fridge I will think of dieting!) or control implementation intentions. Furthermore, they received either a go/no-go task in which behavioral stop signals were presented upon presentation of palatable foods (food go/no-go task), or upon control stimuli. Participants' weight was measured in the laboratory before and after the intervention. Strength of participants' dieting goal and their Body Mass Index (BMI; as a proxy for impulsiveness toward food) were examined as moderators. Results showed that both dieting implementation intentions and the food go/no-go task facilitated weight loss. Moreover, dieting implementation intentions facilitated weight loss particularly among people with a strong current dieting goal, whereas the food go/no-go task facilitated weight loss independent of this factor. Instead, the food go/no-go task, but not formation of dieting implementation intentions, was primarily effective among dieters with a relatively high BMI. These results provide the first preliminary evidence that interventions aimed at targeting impulsive eating-related processes via the internet can facilitate weight loss. Copyright © 2014 Elsevier Ltd. All rights reserved.

  14. Calculating ensemble averaged descriptions of protein rigidity without sampling.

    Directory of Open Access Journals (Sweden)

    Luis C González

    Full Text Available Previous works have demonstrated that protein rigidity is related to thermodynamic stability, especially under conditions that favor formation of native structure. Mechanical network rigidity properties of a single conformation are efficiently calculated using the integer body-bar Pebble Game (PG algorithm. However, thermodynamic properties require averaging over many samples from the ensemble of accessible conformations to accurately account for fluctuations in network topology. We have developed a mean field Virtual Pebble Game (VPG that represents the ensemble of networks by a single effective network. That is, all possible number of distance constraints (or bars that can form between a pair of rigid bodies is replaced by the average number. The resulting effective network is viewed as having weighted edges, where the weight of an edge quantifies its capacity to absorb degrees of freedom. The VPG is interpreted as a flow problem on this effective network, which eliminates the need to sample. Across a nonredundant dataset of 272 protein structures, we apply the VPG to proteins for the first time. Our results show numerically and visually that the rigidity characterizations of the VPG accurately reflect the ensemble averaged [Formula: see text] properties. This result positions the VPG as an efficient alternative to understand the mechanical role that chemical interactions play in maintaining protein stability.

  15. Calculating ensemble averaged descriptions of protein rigidity without sampling.

    Science.gov (United States)

    González, Luis C; Wang, Hui; Livesay, Dennis R; Jacobs, Donald J

    2012-01-01

    Previous works have demonstrated that protein rigidity is related to thermodynamic stability, especially under conditions that favor formation of native structure. Mechanical network rigidity properties of a single conformation are efficiently calculated using the integer body-bar Pebble Game (PG) algorithm. However, thermodynamic properties require averaging over many samples from the ensemble of accessible conformations to accurately account for fluctuations in network topology. We have developed a mean field Virtual Pebble Game (VPG) that represents the ensemble of networks by a single effective network. That is, all possible number of distance constraints (or bars) that can form between a pair of rigid bodies is replaced by the average number. The resulting effective network is viewed as having weighted edges, where the weight of an edge quantifies its capacity to absorb degrees of freedom. The VPG is interpreted as a flow problem on this effective network, which eliminates the need to sample. Across a nonredundant dataset of 272 protein structures, we apply the VPG to proteins for the first time. Our results show numerically and visually that the rigidity characterizations of the VPG accurately reflect the ensemble averaged [Formula: see text] properties. This result positions the VPG as an efficient alternative to understand the mechanical role that chemical interactions play in maintaining protein stability.

  16. Association of Trans-theoretical Model (TTM based Exercise Behavior Change with Body Image Evaluation among Female Iranian Students

    Directory of Open Access Journals (Sweden)

    Sahar Rostami

    2017-03-01

    Full Text Available BackgroundBody image is a determinant of individual attractiveness and physical activity among the young people. This study was aimed to assess the association of Trans-theoretical model based exercise behavior change with body image evaluation among the female Iranian students.Materials and MethodsThis cross-sectional study was conducted in Sanandaj city, Iran in 2016. Using multistage sampling method, a total of 816 high school female students were included in the study. They completed a three-section questionnaire, including demographic information, Trans-theoretical model constructs and body image evaluation. The obtained data were fed into SPSS version 21.0.  ResultsThe results showed more than 60% of participants were in the pre-contemplation and contemplation stages of exercise behavior. The means of perceived self-efficacy, barriers and benefits were found to have a statistically significant difference during the stages of exercise behavior change (P

  17. A daily diary study of self-compassion, body image, and eating behavior in female college students.

    Science.gov (United States)

    Kelly, Allison C; Stephen, Elizabeth

    2016-06-01

    Although self-compassion is associated with healthier body image and eating behavior, these findings have generally emerged at the between-persons level only. The present study investigated the unique contributions of within-person variability in self-compassion, and between-persons differences in self-compassion, to body image and eating behavior. Over seven days, 92 female college students completed nightly measures of self-compassion, self-esteem, dietary restraint, intuitive eating, body appreciation, body satisfaction, and state body image. Multilevel modeling revealed that within-persons, day-to-day fluctuations in self-compassion contributed to day-to-day fluctuations in body image and eating. Between-persons, participants' average levels of self-compassion across days contributed to their average levels of body image and eating over the week. Results generally held when controlling for within- and between-persons self-esteem. Evidently, the eating and body image benefits of self-compassion may come not only from being a generally self-compassionate person, but also from treating oneself more self-compassionately than usual on a given day. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Geometry, rigidity, and group actions

    CERN Document Server

    Farb, Benson; Zimmer, Robert J

    2011-01-01

    The study of group actions is more than a hundred years old but remains to this day a vibrant and widely studied topic in a variety of mathematic fields. A central development in the last fifty years is the phenomenon of rigidity, whereby one can classify actions of certain groups, such as lattices in semi-simple Lie groups. This provides a way to classify all possible symmetries of important spaces and all spaces admitting given symmetries. Paradigmatic results can be found in the seminal work of George Mostow, Gergory Margulis, and Robert J. Zimmer, among others.The p

  19. Transitions in body and behavior: a meta-analytic study on the relationship between pubertal development and adolescent sexual behavior.

    Science.gov (United States)

    Baams, Laura; Dubas, Judith Semon; Overbeek, Geertjan; van Aken, Marcel A G

    2015-06-01

    The present meta-analysis studies the relations of pubertal timing and status with sexual behavior and sexual risk behavior among youth aged 10.5-22.4 years. We included biological sex, age, and ethnicity as potential moderators. Four databases were searched for studies (published between 1980 and 2012) on the relation between pubertal timing or status and sexual behavior. The outcomes were (1) sexual intercourse; (2) combined sexual behavior; and (3) risky sexual behavior. Earlier pubertal timing or more advanced pubertal status was related to earlier and more sexual behavior, and earlier pubertal timing was related to more risky sexual behavior. Further, the links between (1) pubertal status and combined sexual behavior and (2) pubertal timing and sexual intercourse status, combined sexual behavior, and risky sexual behavior were stronger for girls than boys. Most links between pubertal status, timing, and sexual behavior and sexual risk behavior were stronger for younger adolescents. Moderation by ethnicity did not yield consistent results. There was significant variation in results among studies that was not fully explained by differences in biological sex, age, and ethnicity. Future research is needed to identify moderators that explain the variation in effects and to design sexual health interventions for young adolescents. Copyright © 2015 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  20. Gas-induced friction and diffusion of rigid rotors

    Science.gov (United States)

    Martinetz, Lukas; Hornberger, Klaus; Stickler, Benjamin A.

    2018-05-01

    We derive the Boltzmann equation for the rotranslational dynamics of an arbitrary convex rigid body in a rarefied gas. It yields as a limiting case the Fokker-Planck equation accounting for friction, diffusion, and nonconservative drift forces and torques. We provide the rotranslational friction and diffusion tensors for specular and diffuse reflection off particles with spherical, cylindrical, and cuboidal shape, and show that the theory describes thermalization, photophoresis, and the inverse Magnus effect in the free molecular regime.

  1. Cognitive-Behavioral Therapy for Youth with Body Dysmorphic Disorder: Current Status and Future Directions

    Science.gov (United States)

    Phillips, Katharine A.; Rogers, Jamison

    2011-01-01

    SYNOPSIS Body dysmorphic disorder (BDD), a distressing or impairing preoccupation with nonexistent or slight defect(s) in appearance, usually begins during early adolescence and appears to be common in youth. BDD is characterized by substantial impairment in psychosocial functioning and markedly high rates of suicidality. Cognitive-behavioral therapy (CBT) tailored to BDD’s unique features is the best tested and most promising psychosocial treatment for adults with BDD. CBT has been used for youth with BDD, but it has not been systematically developed for or tested in this age group, and there is a pressing need for this work to be done. This article focuses on CBT for BDD in adults and youth, possible adaptations for youth, and the need for treatment research in youth. We also discuss BDD’s prevalence, clinical features, how to diagnose BDD in youth, recommended pharmacotherapy for BDD (serotonin-reuptake inhibitors), and treatments that are not recommended (surgery and other cosmetic treatments). PMID:21440856

  2. Cognitive-Behavioral Therapy for Adolescent Body Dysmorphic Disorder: A Pilot Study.

    Science.gov (United States)

    Greenberg, Jennifer L; Mothi, Suraj Sarvode; Wilhelm, Sabine

    2016-03-01

    Body dysmorphic disorder (BDD) is a relatively common and severe disorder that typically onsets in adolescence, but often goes unrecognized. Despite BDD's severity and early onset, treatment outcome research on adolescent BDD is scarce. Cognitive-behavioral therapy is the gold-standard psychosocial treatment for BDD in adults and has shown promise in adolescents. The current study examined the development and testing of a new CBT for adolescents with BDD. We tested feasibility, acceptability, and treatment outcome in a sample of 13 adolescents (mean age 15.23years, range: 13-17) with primary BDD. Treatment was delivered in 12-22 weekly individual sessions. Standardized clinician ratings and self-report measures were used to assess BDD and related symptoms pre- and posttreatment and at 3- and 6-months follow-up. At posttreatment, BDD and related symptoms (e.g., insight, mood) were significantly improved. Scores on the Yale-Brown Obsessive Compulsive Scale for BDD indicated a 50% (intent-to-treat) and 68% (completer) improvement in BDD symptoms. Seventy-five percent of adolescents who started treatment and 100% of completers were considered treatment responders. Treatment gains were maintained at follow-up. High patient satisfaction ratings and patient feedback indicated that treatment was acceptable. This represents the largest study of a psychosocial treatment for adolescent BDD. Copyright © 2015. Published by Elsevier Ltd.

  3. Pareidolias in REM Sleep Behavior Disorder: A Possible Predictive Marker of Lewy Body Diseases?

    Science.gov (United States)

    Sasai-Sakuma, Taeko; Nishio, Yoshiyuki; Yokoi, Kayoko; Mori, Etsuro; Inoue, Yuichi

    2017-02-01

    To investigate conditions and clinical significance of pareidolias in patients with idiopathic rapid eyemovent (REM) sleep behavior disorder (iRBD). This cross-sectional study examined 202 patients with iRBD (66.8 ± 8.0 yr, 58 female) and 46 healthy control subjects (64.7 ± 5.8 years, 14 females). They underwent the Pareidolia test, a newly developed instrument for evoking pareidolias, video polysomnography, olfactory tests, and Addenbrooke's cognitive examination-revised. Results show that 53.5% of iRBD patients exhibited one or more pareidolic responses: The rate was higher than control subjects showed (21.7%). The pictures evoking pareidolic responses were more numerous for iRBD patients than for control subjects (1.2 ± 1.8 vs. 0.4 ± 0.8, p Pareidolias in iRBD are useful as a predictive marker of future development of Lewy body diseases. © Sleep Research Society 2017. Published by Oxford University Press on behalf of the Sleep Research Society. All rights reserved. For permissions, please e-mail journals.permissions@oup.com.

  4. Parenting styles, feeding styles, and their influence on child obesogenic behaviors and body weight. A review.

    Science.gov (United States)

    Vollmer, Rachel L; Mobley, Amy R

    2013-12-01

    With recommendations to include parents as targets for childhood obesity interventions, there is a need to review the relationship of general parenting influences on childhood obesity. Therefore, the aim of this review is to examine the existing literature regarding the influence of parenting style and/or feeding styles on childhood obesogenic behaviors and body weight. Research articles related to parenting style (n=40) and parental feeding style (n=11) were identified and reviewed. An authoritative style appears to be the most protective parenting and feeding style while the indulgent feeding style is consistently associated with negative health outcomes. Overall, results for parenting style studies are inconsistent due to differences in conceptualization and measurement, while the results for feeding styles are much more cohesive. The literature is lacking in the ability to describe the interplay between parenting and feeding styles and child obesity risk. Recommendations for future research and interventions are discussed in regards to feeding style and influences on childhood obesity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  5. Patterns of Body Image Concerns and Disordered Weight- and Shape-Related Behaviors in Heterosexual and Sexual Minority Adolescent Males

    Science.gov (United States)

    Calzo, Jerel P.; Masyn, Katherine E.; Corliss, Heather L.; Scherer, Emily A.; Field, Alison E.; Austin, S. Bryn

    2015-01-01

    This study investigates body image concerns and disordered weight- and shape-related behaviors across adolescence and young adulthood in males and how patterns vary by sexual orientation. Participants were 5,388 males from the U.S. national Growing Up Today Study. In 2001, 2003, and 2005 (spanning ages 15-20 years), participants reported sexual…

  6. Taking Care of You: Body, Mind, Spirit--A Unique Stress Management Program That Improves Lifestyle Behaviors

    Science.gov (United States)

    Vetter-Smith, Molly; Massey, Vera; Rellergert, Linda; Wissmann, Mary

    2014-01-01

    Taking Care of You: Body, Mind, Spirit is a multi-session group program developed by University of Missouri Extension that provides a unique and practical approach to helping adults better managing their stress and bounce back from life's challenges while improving lifestyle behaviors. The program combines mindfulness and a variety of other…

  7. Hispanic maternal influences on daughters' unhealthy weight control behaviors: The role of maternal acculturation, adiposity, and body image disturbances.

    Science.gov (United States)

    Olvera, Norma; Matthews-Ewald, Molly R; McCarley, Kendall; Scherer, Rhonda; Posada, Alexandria

    2016-12-01

    This study examined whether maternal adiposity, acculturation, and perceived-ideal body size discrepancy for daughters were associated with daughters' engagement in unhealthy weight control behaviors. A total of 97 Hispanic mother-daughter dyads completed surveys, rated a figure scale, and had their height, weight, and adiposity assessed. Mothers (M age =39.00, SD=6.20 years) selected larger ideal body sizes for their daughters (M age =11.12, SD=1.53 years) than their daughters selected for themselves. Mothers had a smaller difference between their perception of their daughters' body size and ideal body size compared to the difference between their daughters' selection of their perceived and ideal body size. More acculturated mothers and those mothers with larger waist-to-hip ratios were more likely to have daughters who engaged in unhealthy weight control behaviors. These findings highlight the relevant role that maternal acculturation and adiposity may have in influencing daughters' unhealthy weight control behaviors. Published by Elsevier Ltd.

  8. Associations between body mass index, weight control concerns and behaviors, and eating disorder symptoms among non-clinical Chinese adolescents

    Science.gov (United States)

    2010-01-01

    Background Previous research with adolescents has shown associations of body weight, weight control concerns and behaviors with eating disorder symptoms, but it is unclear whether these associations are direct or whether a mediating effect exists. This study was conducted to investigate the prevalence of overweight and obesity, weight control concerns and behaviors, and eating disorder symptoms and to examine the mediating function of weight control concerns and behaviors on the relationship between body mass index (BMI) and eating disorder symptoms among non-clinical adolescents in China. Methods A cross-sectional survey among 2019 adolescent girls and 1525 adolescent boys in the 7th, 8th, 10th and 11th grades from seven cities in China was conducted. Information on weight control concerns and behaviors, and eating disorder symptoms (Eating Disorder Inventory-3) were collected from the adolescents using a self-administrated questionnaire. Results Weight control concerns and behaviors, and eating disorder symptoms were prevalent among the study population. A high proportion of adolescents scored at or above the threshold on the eating disorder inventory (EDI) subscale such as bulimia, interoceptive deficits, perfectionism, and maturity fears, which indicated eating disorder symptoms. High BMI was significantly associated with high score of drive for thinness, body dissatisfaction, bulimia, low self-esteem, interceptive deficits and maturity fears, so do perceived body weight status. Almost all weight control concerns and behaviors we investigated were significantly associated with high EDI subscale scores. When weight control concerns were added to the model, as shown in the model, the association between BMI and tendency of drive to thinness and bulimia was attenuated but still kept significant. The association between BMI and body dissatisfaction were no further significant. The association of BMI and drive for thinness, body dissatisfaction and bulimia was

  9. Associations between body mass index, weight control concerns and behaviors, and eating disorder symptoms among non-clinical Chinese adolescents

    Directory of Open Access Journals (Sweden)

    Hu Xiaoqi

    2010-06-01

    Full Text Available Abstract Background Previous research with adolescents has shown associations of body weight, weight control concerns and behaviors with eating disorder symptoms, but it is unclear whether these associations are direct or whether a mediating effect exists. This study was conducted to investigate the prevalence of overweight and obesity, weight control concerns and behaviors, and eating disorder symptoms and to examine the mediating function of weight control concerns and behaviors on the relationship between body mass index (BMI and eating disorder symptoms among non-clinical adolescents in China. Methods A cross-sectional survey among 2019 adolescent girls and 1525 adolescent boys in the 7th, 8th, 10th and 11th grades from seven cities in China was conducted. Information on weight control concerns and behaviors, and eating disorder symptoms (Eating Disorder Inventory-3 were collected from the adolescents using a self-administrated questionnaire. Results Weight control concerns and behaviors, and eating disorder symptoms were prevalent among the study population. A high proportion of adolescents scored at or above the threshold on the eating disorder inventory (EDI subscale such as bulimia, interoceptive deficits, perfectionism, and maturity fears, which indicated eating disorder symptoms. High BMI was significantly associated with high score of drive for thinness, body dissatisfaction, bulimia, low self-esteem, interceptive deficits and maturity fears, so do perceived body weight status. Almost all weight control concerns and behaviors we investigated were significantly associated with high EDI subscale scores. When weight control concerns were added to the model, as shown in the model, the association between BMI and tendency of drive to thinness and bulimia was attenuated but still kept significant. The association between BMI and body dissatisfaction were no further significant. The association of BMI and drive for thinness, body

  10. Reciprocal effects among changes in weight, body image, and other psychological factors during behavioral obesity treatment: a mediation analysis

    Directory of Open Access Journals (Sweden)

    Barata José T

    2009-02-01

    Full Text Available Abstract Background Changes in body image and subjective well-being variables (e.g. self-esteem are often reported as outcomes of obesity treatment. However, they may, in turn, also influence behavioral adherence and success in weight loss. The present study examined associations among obesity treatment-related variables, i.e., change in weight, quality of life, body image, and subjective well-being, exploring their role as both mediators and outcomes, during a behavioral obesity treatment. Methods Participants (BMI = 31.1 ± 4.1 kg/m2; age = 38.4 ± 6.7 y were 144 women who attended a 12-month obesity treatment program and a comparison group (n = 49, who received a general health education program. The intervention included regular group meetings promoting lasting behavior changes in physical activity and dietary intake. Body image, quality of life, subjective well-being, and body weight were measured at baseline and treatment's end. Mediation was tested by multiple regression and a resampling approach to measure indirect effects. Treatment group assignment was the independent variable while changes in weight and in psychosocial variables were analyzed alternatively as mediators and as dependent variables. Results At 12 months, the intervention group had greater weight loss (-5.6 ± 6.8% vs. -1.2 ± 4.6%, p Conclusion Changes in weight and body image may reciprocally affect each other during the course of behavioral obesity treatment. No evidence of reciprocal relationships was found for the other models under analysis; however, weight changes partially explained the effects of treatment on quality of life and self-esteem. Weight and psychosocial changes co-occur during treatment and will probably influence each other dynamically, in ways not yet adequately understood. Results from this study support the inclusion of intervention contents aimed at improving body image in weight management programs.

  11. Strategic rigidity and foresight for technology adoption among electric utilities

    International Nuclear Information System (INIS)

    Shah, Arsalan Nisar; Palacios, Miguel; Ruiz, Felipe

    2013-01-01

    The variation in the adoption of a technology as a major source of competitive advantage has been attributed to the wide-ranging strategic foresight and the integrative capability of a firm. These possible areas of competitive advantage can exist in the periphery of the firm's strategic vision and can get easily blurred as a result of rigidness and can permeate in the decision-making process of the firm. This article explores how electric utility firms with a renewable energy portfolio can become strategically rigid in terms of adoption of newer technologies. The reluctance or delay in the adoption of new technology can be characterized as strategic rigidness, brought upon as a result of a firm's core competence or core capability in the other, more conventional technology arrangement. This paper explores the implications of such rigidness on the performance of a firm and consequently on the energy eco-system. The paper substantiates the results by emphasizing the case of Iberdrola S.A., an incumbent firm as a wind energy developer and its adoption decision behavior. We illustrate that the very routines that create competitive advantage for firms in the electric utility industry are vulnerable as they might also develop as sources of competitive disadvantage, when firms confront environmental change and uncertainty. - Highlights: • Present a firm-level perspective on technology adoption behavior among electric utilities. • Firms with mature technology can become rigid towards newer technologies. • Case study analysis of a major electric utility firm. • Implications of ‘technology rigidness’ on the energy eco-system

  12. Two sides of the same coin? A new instrument to assess body checking and avoidance behaviors in eating disorders.

    Science.gov (United States)

    Legenbauer, Tanja; Martin, Franziska; Blaschke, Ariane; Schwenzfeier, Anne; Blechert, Jens; Schnicker, Katja

    2017-06-01

    Body checking (BC) and avoidance behaviors (BA) are the dominant behavioral features of body image disturbances (BID) that characterize most individuals with eating disorders (EDs). Whereas BC can be reliably assessed, a valid assessment tool for BA is lacking, preventing an adequate assessment of BID differences across different EDs (anorexia nervosa, AN; bulimia nervosa, BN; binge eating disorder, BED). A total of 310 women with EDs and 112 nonclinical controls completed measures of BC-, BA- and ED-related symptoms. BA did not differentiate between EDs, whereas BC did: it was highest in AN and BN, and lowest in BED. Multivariate analyses also discriminated AN from BN based on BC. Given that results are of preliminary nature, evidence is promising that EDs can be discriminated from healthy controls and that differential BID profiles for the behavioral component among ED subgroups exist. However, replication of the factor structure remains open within ED subsamples. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Mind magic: a pilot study of preventive mind-body-based stress reduction in behaviorally inhibited and activated children.

    Science.gov (United States)

    Jellesma, Francine C; Cornelis, Janine

    2012-03-01

    The aim of this pilot study was to examine a mind-body-based preventive intervention program and to determine relationships between children's behavioral inhibition system (BIS) and behavioral activation system, stress, and stress reduction after the program. Children participated in the program (n=30) or in a control condition (n=24). They filled out questionnaires before and after the program and reported their levels of stress before and after each of the five sessions. The program consisted of weekly sessions. Each session incorporated yoga postures, visualization, and social exercises. Breathing techniques were integrated. Stress reductions were only seen in the intervention group and mainly in children with high BIS--irrespective of their behavioral activation system. The results demonstrate that children with high BIS may benefit from a mind-body-based stress reduction program.

  14. Obesity, body image, and its impact on children's eating and exercise behaviors in China: A nationwide longitudinal study.

    Science.gov (United States)

    Min, Jungwon; Yan, Alice Fang; Wang, Vivian H C; Wang, Youfa

    2018-01-01

    Body image seems to mediate the association between obesity and health behaviors as well as weight control attempts. We examined the distribution of children's body image by demographic characteristics and their subsequent associations with eating, exercise, and weight change. Child body image and health behaviors from the China Health National Survey 2000-2011 were assessed at baseline and in follow-up for 6- to 17-year-old children during 2000-2011 using mixed models. There was a large discrepancy between children's actual weight status (overweight: 16.9%) vs. self-rated body image (fat: 2.4% in 2011). Less than 1% of children desired a fat body; girls were more likely to want to be thin (52.5% vs. 40.9%) than boys. About 11% of children needed to lose weight in order to be at their desired baseline. During follow-up, those needing weight loss to be as desired were more likely to attempt dieting to change their weight (OR, 95% CI=1.9, 1.1-3.5 in boys; 1.7, 1.1-2.5 in girls) and less likely to feel they had enough physical activity (OR, 95% CI=0.5, 0.4-0.7 in boys; 0.6, 0.5-0.9 in girls), although their weight gain had been significantly higher than those having consistent self and desired body images (β [SE]=0.4 [0.1] in boys; 0.2 [0.1] in girls, all pbody image discrepancy. The discrepancy in self vs. desired body image motivated children to change their obesity-related health behaviors among non-overweight children in China. Copyright © 2017 Elsevier Inc. All rights reserved.

  15. A Pilot Randomized Controlled Trial of Cognitive-Behavioral Therapy for Adolescents With Body Dysmorphic Disorder.

    Science.gov (United States)

    Mataix-Cols, David; Fernández de la Cruz, Lorena; Isomura, Kayoko; Anson, Martin; Turner, Cynthia; Monzani, Benedetta; Cadman, Jacinda; Bowyer, Laura; Heyman, Isobel; Veale, David; Krebs, Georgina

    2015-11-01

    Body dysmorphic disorder (BDD) typically starts in adolescence, but evidence-based treatments are yet to be developed and formally evaluated in this age group. We designed an age-appropriate cognitive-behavioral therapy (CBT) protocol for adolescents with BDD and evaluated its acceptability and efficacy in a pilot randomized controlled trial. Thirty adolescents aged 12 to 18 years (mean = 16.0, SD = 1.7) with a primary diagnosis of BDD, together with their families, were randomly assigned to 14 sessions of CBT delivered over 4 months or a control condition of equivalent duration, consisting of written psycho-education materials and weekly telephone monitoring. Blinded evaluators assessed participants at baseline, midtreatment, posttreatment, and at 2-month follow-up. The primary outcome measure was the Yale-Brown Obsessive-Compulsive Scale Modified for BDD, Adolescent Version (mean baseline score = 37.13, SD = 4.98, range = 24-43). The CBT group showed a significantly greater improvement than the control group, both at posttreatment (time × group interaction coefficient [95% CI] = -11.26 [-17.22 to -5.31]; p = .000) and at 2-month follow-up (time × group interaction coefficient [95% CI] = -9.62 [-15.74 to -3.51]; p = .002). Six participants (40%) in the CBT group and 1 participant (6.7%) in the control condition were classified as responders at both time points (χ(2) = 4.658, p = .031). Improvements were also seen on secondary measures, including insight, depression, and quality of life at posttreatment. Both patients and their families deemed the treatment as highly acceptable. Developmentally tailored CBT is a promising intervention for young people with BDD, although there is significant room for improvement. Further clinical trials incorporating lessons learned in this pilot study and comparing CBT and pharmacological therapies, as well as their combination, are warranted. Cognitive-Behaviour Therapy for Adolescents With Body Dysmorphic Disorder; http

  16. Connections rigidity effect on probability of fracture in steel moment frames

    Directory of Open Access Journals (Sweden)

    Gholamreza Abdollahzadeh

    2017-08-01

    Full Text Available Connections in steel moment frames are idealized in full pinned and full rigid conditions. Because with this assumption, in spite of real behavior of connection, real story drifts are less anticipated and maybe frame is designed without performance of bracing. There are several methods for modeling actual behavior of semi rigid connections. In this method a connection with certain rigidity is modeled by a rotational spring with corresponding stiffness. This stiffness is achieved by certain formula. In other words, each percent of rigidity corresponds to one rotational spring stiffness. In this research in order to evaluate the real behavior of connection in analysis and designing process and fracture probability one frame including four stories and one bay with three types of connection has been modeled and designed in ETABS. Each model has an individual rigidity which is equal to 10, 75 and 90 percent. With respect to maximum drift and different PGA in roof, probabilities of low, medium, high and complete fracture were calculated. For this purpose, with applying different PGA to modeled frames, amounts of drift in the roof are achieved. Then these values are compared with given values in American code. Finally, investigation showed that when rigidity in frame connections increases, the probability of frame fracture decreases. In other words, fully rigid assumption of connection in analysis process leads to decreasing in real probability of fracture in frames which is a noticeable risk in building designing processes.

  17. [Weight control behaviors in dieting adolescent girls and their relation to body dissatisfaction and obsession with thinness].

    Science.gov (United States)

    Contreras, M Liliana A; Morán, Javier K; Frez, Scarlett H; Lagos, Carola O; Marín, María Paz F; de los Ángeles Pinto B, María; Suzarte, Érika A

    2015-01-01

    Obsession with thinness and body dissatisfaction can lead adolescents to follow unsupervised diets, which could result in risky weight control behaviors such as fasting, vomiting, use of diuretics and laxatives. The aim of the current study is to examine weight control behaviors in dieting adolescents and relate them to body dissatisfaction (BD) and obsession with thinness (OT). A cross-sectional study was conducted on 439 adolescents from Valparaiso public schools to investigate risky weight control behaviors due to BD and OT scales from the Eating Disorders Inventory-2 (EDI-2), comparing restrained eaters and non-restrained eaters. A total of 43% adolescents had followed a weight loss diet without medical supervision. The dieters had higher BD and OT values. Moderate to severe food restriction, based on expert judgment, was observed in 29.6%, and differences in the presence and severity of purging behaviors were found between the 2 groups. One third of the adolescents studied followed diets without professional supervision and had higher BD and OT values, as well as risky weight control behaviors. Overweight and obese adolescents followed more restrictive diets and developed riskier weight control behaviors. Copyright © 2015. Publicado por Elsevier España, S.L.U.

  18. Long-Term Outcomes of Cognitive-Behavioral Therapy for Adolescent Body Dysmorphic Disorder.

    Science.gov (United States)

    Krebs, Georgina; de la Cruz, Lorena Fernández; Monzani, Benedetta; Bowyer, Laura; Anson, Martin; Cadman, Jacinda; Heyman, Isobel; Turner, Cynthia; Veale, David; Mataix-Cols, David

    2017-07-01

    Emerging evidence suggests that cognitive-behavioral therapy (CBT) is an efficacious treatment for adolescent body dysmorphic disorder (BDD) in the short term, but longer-term outcomes remain unknown. The current study aimed to follow up a group of adolescents who had originally participated in a randomized controlled trial of CBT for BDD to determine whether treatment gains were maintained. Twenty-six adolescents (mean age = 16.2, SD = 1.6) with a primary diagnosis of BDD received a course of developmentally tailored CBT and were followed up over 12 months. Participants were assessed at baseline, midtreatment, posttreatment, 2-, 6-, and 12-month follow-up. The primary outcome measure was the clinician-rated Yale-Brown Obsessive-Compulsive Scale Modified for BDD. Secondary outcomes included measures of insight, depression, quality of life, and global functioning. BDD symptoms decreased significantly from pre- to posttreatment and remained stable over the 12-month follow-up. At this time point, 50% of participants were classified as responders and 23% as remitters. Participants remained significantly improved on all secondary outcomes at 12-month follow-up. Neither baseline insight nor baseline depression predicted long-term outcomes. The positive effects of CBT appear to be durable up to 12-month follow-up. However, the majority of patients remained symptomatic and vulnerable to a range of risks at 12-month follow-up, indicating that longer-term monitoring is advisable in this population. Future research should focus on enhancing the efficacy of CBT in order to improve long-term outcomes. Copyright © 2017. Published by Elsevier Ltd.

  19. Modular cognitive-behavioral therapy for body dysmorphic disorder: a randomized controlled trial.

    Science.gov (United States)

    Wilhelm, Sabine; Phillips, Katharine A; Didie, Elizabeth; Buhlmann, Ulrike; Greenberg, Jennifer L; Fama, Jeanne M; Keshaviah, Aparna; Steketee, Gail

    2014-05-01

    There are few effective treatments for body dysmorphic disorder (BDD) and a pressing need to develop such treatments. We examined the feasibility, acceptability, and efficacy of a manualized modular cognitive-behavioral therapy for BDD (CBT-BDD). CBT-BDD utilizes core elements relevant to all BDD patients (e.g., exposure, response prevention, perceptual retraining) and optional modules to address specific symptoms (e.g., surgery seeking). Thirty-six adults with BDD were randomized to 22 sessions of immediate individual CBT-BDD over 24 weeks (n=17) or to a 12-week waitlist (n=19). The Yale-Brown Obsessive-Compulsive Scale Modified for BDD (BDD-YBOCS), Brown Assessment of Beliefs Scale, and Beck Depression Inventory-II were completed pretreatment, monthly, posttreatment, and at 3- and 6-month follow-up. The Sheehan Disability Scale and Client Satisfaction Inventory (CSI) were also administered. Response to treatment was defined as ≥30% reduction in BDD-YBOCS total from baseline. By week 12, 50% of participants receiving immediate CBT-BDD achieved response versus 12% of waitlisted participants (p=0.026). By posttreatment, 81% of all participants (immediate CBT-BDD plus waitlisted patients subsequently treated with CBT-BDD) met responder criteria. While no significant group differences in BDD symptom reduction emerged by Week 12, by posttreatment CBT-BDD resulted in significant decreases in BDD-YBOCS total over time (d=2.1, p<0.0001), with gains maintained during follow-up. Depression, insight, and disability also significantly improved. Patient satisfaction was high, with a mean CSI score of 87.3% (SD=12.8%) at posttreatment. CBT-BDD appears to be a feasible, acceptable, and efficacious treatment that warrants more rigorous investigation. Copyright © 2014. Published by Elsevier Ltd.

  20. Eating Habits and Body Weight Control Behaviors of High School Students

    Directory of Open Access Journals (Sweden)

    Aynur CETINKAYA

    2007-04-01

    Full Text Available The nutritional needs increase in puberty due to rapid growth and changes in body composition. Because of that healthy eating is vital for teen’s health. The aim of this study was to determine eating habits and weight control behaviors of high school students. A cross-sectional study was performed involving all (6 public and 3 private tenth-grade high schools in Manisa city. Two thousand one hundred forty six students completed a questionnaire which consists of 26 items and was designed by researchers. Among all students surveyed, 34.0% reported that they don’t have a habit to eat breakfast regularly, 38.3% reported that they don’t have a habit to eat lunch regularly, 6.5% reported that they don’t have a habit to eat dinner regularly, 36.7% reported that they were afraid getting fat, 6.5% reported that they were dieting, 39.4% reported that they don’t make sport regularly and 59.1% reported that they were snacking frequently. In this study it has seen that skipping meals is a common eating habit in high school students and many of them fail to eat three regular meals per day. On the other hand it has seen that students don’t have regular exercise habits. The results of this study have suggested that there is a need to encourage teens a healthy lifestyle that incorporates eating habits and regular exercise. [TAF Prev Med Bull. 2007; 6(2: 98-105

  1. Eating Habits and Body Weight Control Behaviors of High School Students

    Directory of Open Access Journals (Sweden)

    Dilek OZMEN

    2007-04-01

    Full Text Available The nutritional needs increase in puberty due to rapid growth and changes in body composition. Because of that healthy eating is vital for teen’s health. The aim of this study was to determine eating habits and weight control behaviors of high school students. A cross-sectional study was performed involving all (6 public and 3 private tenth-grade high schools in Manisa city. Two thousand one hundred forty six students completed a questionnaire which consists of 26 items and was designed by researchers. Among all students surveyed, 34.0% reported that they don’t have a habit to eat breakfast regularly, 38.3% reported that they don’t have a habit to eat lunch regularly, 6.5% reported that they don’t have a habit to eat dinner regularly, 36.7% reported that they were afraid getting fat, 6.5% reported that they were dieting, 39.4% reported that they don’t make sport regularly and 59.1% reported that they were snacking frequently. In this study it has seen that skipping meals is a common eating habit in high school students and many of them fail to eat three regular meals per day. On the other hand it has seen that students don’t have regular exercise habits. The results of this study have suggested that there is a need to encourage teens a healthy lifestyle that incorporates eating habits and regular exercise. [TAF Prev Med Bull 2007; 6(2.000: 98-105

  2. Body mass index, nutritional knowledge, and eating behaviors in elite student and professional ballet dancers.

    Science.gov (United States)

    Wyon, Matthew A; Hutchings, Kate M; Wells, Abigail; Nevill, Alan M

    2014-09-01

    It is recognized that there is a high esthetic demand in ballet, and this has implications on dancers' body mass index (BMI) and eating behaviors. The objective of this study was to examine the association between BMI, eating attitudes, and nutritional knowledge of elite student and professional ballet dancers. Observational design. Institutional. One hundred eighty-nine participants from an elite full-time dance school (M = 53, F = 86) and from an elite ballet company (M = 16, F = 25) volunteered for the study. There were no exclusion criteria. Anthropometric data (height and mass), General Nutrition Knowledge Questionnaire (GNKQ), and the Eating Attitude Test-26 (EAT-26) were collected from each participant. Univariate analysis of variance was used to examine differences in gender and group for BMI, GNKQ, and EAT-26. Regression analyses were applied to examine interactions between BMI, GNKQ, and EAT-26. Professional dancers had significantly greater BMI than student dancers (P < 0.001), and males had significantly higher BMI scores than females (P < 0.05). Food knowledge increased with age (P < 0.001) with no gender difference. Student dancers had a significant interaction between year group and gender because of significantly higher EAT-26 scores for females in years 10 and 12. Regression analysis of the subcategories (gender and group) reported a number of significant relationships between BMI, GNKQ, and EAT-26. The findings suggest that dancers with disordered eating also display lower levels of nutritional knowledge, and this may have an impact on BMI. Female students' eating attitudes and BMI should especially be monitored during periods of adolescent development.

  3. "The mind is willing, but the flesh is weak": the effects of mind-body dualism on health behavior.

    Science.gov (United States)

    Forstmann, Matthias; Burgmer, Pascal; Mussweiler, Thomas

    2012-10-01

    Beliefs in mind-body dualism--that is, perceiving one's mind and body as two distinct entities--are evident in virtually all human cultures. Despite their prevalence, surprisingly little is known about the psychological implications of holding such beliefs. In the research reported here, we investigated the relationship between dualistic beliefs and health behaviors. We theorized that holding dualistic beliefs leads people to perceive their body as a mere "shell" and, thus, to neglect it. Supporting this hypothesis, our results showed that participants who were primed with dualism reported less engagement in healthy behaviors and less positive attitudes toward such behaviors than did participants primed with physicalism. Additionally, we investigated the bidirectionality of this link. Activating health-related concepts affected participants' subsequently reported metaphysical beliefs in mind-body dualism. A final set of studies demonstrated that participants primed with dualism make real-life decisions that may ultimately compromise their physical health (e.g., consuming unhealthy food). These findings have potential implications for health interventions.

  4. Genetic variability of environmental sensitivity revealed by phenotypic variation in body weight and (its correlations to physiological and behavioral traits.

    Directory of Open Access Journals (Sweden)

    Delphine Lallias

    Full Text Available Adaptive phenotypic plasticity is a key component of the ability of organisms to cope with changing environmental conditions. Fish have been shown to exhibit a substantial level of phenotypic plasticity in response to abiotic and biotic factors. In the present study, we investigate the link between environmental sensitivity assessed globally (revealed by phenotypic variation in body weight and more targeted physiological and behavioral indicators that are generally used to assess the sensitivity of a fish to environmental stressors. We took advantage of original biological material, the rainbow trout isogenic lines, which allowed the disentangling of the genetic and environmental parts of the phenotypic variance. Ten lines were characterized for the changes of body weight variability (weight measurements taken every month during 18 months, the plasma cortisol response to confinement stress (3 challenges and a set of selected behavioral indicators. This study unambiguously demonstrated the existence of genetic determinism of environmental sensitivity, with some lines being particularly sensitive to environmental fluctuations and others rather insensitive. Correlations between coefficient of variation (CV for body weight and behavioral and physiological traits were observed. This confirmed that CV for body weight could be used as an indicator of environmental sensitivity. As the relationship between indicators (CV weight, risk-taking, exploration and cortisol was shown to be likely depending on the nature and intensity of the stressor, the joint use of several indicators should help to investigate the biological complexity of environmental sensitivity.

  5. Lateral hypothalamic GLP-1 receptors are critical for the control of food reinforcement, ingestive behavior and body weight.

    Science.gov (United States)

    López-Ferreras, L; Richard, J E; Noble, E E; Eerola, K; Anderberg, R H; Olandersson, K; Taing, L; Kanoski, S E; Hayes, M R; Skibicka, K P

    2017-09-12

    Increased motivation for highly rewarding food is a major contributing factor to obesity. Most of the literature focuses on the mesolimbic nuclei as the core of reward behavior regulation. However, the lateral hypothalamus (LH) is also a key reward-control locus in the brain. Here we hypothesize that manipulating glucagon-like peptide-1 receptor (GLP-1R) activity selectively in the LH can profoundly affect food reward behavior, ultimately leading to obesity. Progressive ratio operant responding for sucrose was examined in male and female rats, following GLP-1R activation and pharmacological or genetic GLP-1R blockade in the LH. Ingestive behavior and metabolic parameters, as well as molecular and efferent targets, of the LH GLP-1R activation were also evaluated. Food motivation was reduced by activation of LH GLP-1R. Conversely, acute pharmacological blockade of LH GLP-1R increased food motivation but only in male rats. GLP-1R activation also induced a robust reduction in food intake and body weight. Chronic knockdown of LH GLP-1R induced by intraparenchymal delivery of an adeno-associated virus-short hairpin RNA construct was sufficient to markedly and persistently elevate ingestive behavior and body weight and ultimately resulted in a doubling of fat mass in males and females. Interestingly, increased food reinforcement was again found only in males. Our data identify the LH GLP-1R as an indispensable element of normal food reinforcement, food intake and body weight regulation. These findings also show, for we believe the first time, that brain GLP-1R manipulation can result in a robust and chronic body weight gain. The broader implications of these findings are that the LH differs between females and males in its ability to control motivated and ingestive behaviors.Molecular Psychiatry advance online publication, 12 September 2017; doi:10.1038/mp.2017.187.

  6. Topological orders in rigid states

    International Nuclear Information System (INIS)

    Wen, X.G.

    1990-01-01

    The authors study a new kind of ordering topological order in rigid states (the states with no local gapless excitations). This paper concentrates on characterization of the different topological orders. As an example the authors discuss in detail chiral spin states of 2+1 dimensional spin systems. Chiral spin states are described by the topological Chern-Simons theories in the continuum limit. The authors show that the topological orders can be characterized by a non-Abelian gauge structure over the moduli space which parametrizes a family of the model Hamiltonians supporting topologically ordered ground states. In 2 + 1 dimensions, the non-Abelian gauge structure determines possible fractional statistics of the quasi-particle excitations over the topologically ordered ground states. The dynamics of the low lying global excitations is shown to be independent of random spatial dependent perturbations. The ground state degeneracy and the non-Abelian gauge structures discussed in this paper are very robust, even against those perturbations that break translation symmetry. The authors also discuss the symmetry properties of the degenerate ground states of chiral spin states. The authors find that some degenerate ground states of chiral spin states on torus carry non-trivial quantum numbers of the 90 degrees rotation

  7. Pretty as a Princess: Longitudinal Effects of Engagement with Disney Princesses on Gender Stereotypes, Body Esteem, and Prosocial Behavior in Children

    Science.gov (United States)

    Coyne, Sarah M.; Linder, Jennifer Ruh; Rasmussen, Eric E.; Nelson, David A.; Birkbeck, Victoria

    2016-01-01

    This study examined level of engagement with Disney Princess media/products as it relates to gender-stereotypical behavior, body esteem (i.e. body image), and prosocial behavior during early childhood. Participants consisted of 198 children (M[subscript age] = 58 months), who were tested at two time points (approximately 1 year apart). Data…

  8. Weight Gain in Breast Cancer Patients on Chemotheraphy: Exploring Hormonal Body Composition and Behavioral Mechanisms

    National Research Council Canada - National Science Library

    Kumar, Nagi

    1999-01-01

    Purpose: The purpose of this study is to prospectively and systematically observe the relative contribution of each viable mechanism such as nutritional intake, activity levels, body composition, hormonal...

  9. Association Among Internet Usage, Body Image and Eating Behaviors of Secondary School Students

    OpenAIRE

    KAEWPRADUB, Natthakarn; KIATRUNGRIT, Komsan; HONGSANGUANSRI, Sirichai; PAVASUTHIPAISIT, Chosita

    2017-01-01

    Background Presently, the internet plays a big role in daily life, especially for adolescents. In this age group, they are more concerned about their face and body shape. Despite the numerous studies on the effect traditional media has on body image, very few have focused on the effect of newer forms of media (e.g. online media). And almost none have looked at the relationship between time spent online and body image. Aim To study the associations between time spent on the internet, body imag...

  10. ANALYTIC EVALUATION OF RECTILINEARITY OF LOW RIGIDITY SHAFT DURING HARDENING PROCESS

    Directory of Open Access Journals (Sweden)

    Antoni Świć

    2013-03-01

    Full Text Available The essential influence of the unevenness of temperature distribution while heating in the technological process on dimensions stability of low rigidity elements was shown. The new approach was applied to formulate mathematical models, which describe the elastic and inelastic behaviour of piece using transfer functions and block diagrams, allowing to use frequency method for evaluation of the behaviour of dynamic semi-finished element as the rigid body.

  11. Corrosion behavior of coated and uncoated bio implants in SBF(simulated body fluid)

    International Nuclear Information System (INIS)

    Iqbal, W.; Zahra, N.; Alam, S.; Habib, F.; Irfan, M.

    2013-01-01

    Surgical implants used in medical applications are basically the specific type of stainless steel materials. Stainless steel has been used widely and successfully for various types of trauma and orthopedic reconstructions. If an uncoated (bare) stainless steel metal piece is implanted in any part of the body, it will get corrode in Simulated Body Fluid (SBF) present inside the human body (a mixture of different salts). To overcome this problem a coating of Titanium Nitride (TiN) was developed on stainless steel bio-implants using physical vapor deposition (PVD) method. Both coated and uncoated implants were kept dipped in Simulated Body Fluid for five months. The samples were removed and tested for corrosion life assessment after every fifteen days using weight loss method. (author)

  12. Numerical simulation of thermal behaviors of a clothed human body with evaluation of indoor solar radiation

    International Nuclear Information System (INIS)

    Mao, Aihua; Luo, Jie; Li, Yi

    2017-01-01

    Highlights: • Solar radiation evaluation is integrated with the thermal transfer in clothed humans. • Thermal models are developed for clothed humans exposed in indoor solar radiation. • The effect of indoor solar radiation on humans can be predicted in different situations in living. • The green solar energy can be efficiently utilized in the building development. - Abstract: Solar radiation is a valuable green energy, which is important in achieving a successful building design for thermal comfort in indoor environment. This paper considers solar radiation indoors into the transient thermal transfer models of a clothed human body and offers a new numerical method to analyze the dynamic thermal status of a clothed human body under different solar radiation incidences. The evaluation model of solar radiation indoors and a group of coupled thermal models of the clothed human body are developed and integrated. The simulation capacities of these integrated models are validated through a comparison between the predicted results and the experimental data in reference. After that, simulation cases are also conducted to show the influence of solar radiation on the thermal status of individual clothed body segments when the human body is staying indoors in different seasons. This numerical simulation method provides a useful tool to analyze the thermal status of clothed human body under different solar radiation incidences indoors and thus enables the architect to efficiently utilize the green solar energy in building development.

  13. GPU-based discrete element rigid body transport

    CSIR Research Space (South Africa)

    Govender, Nicolin

    2013-08-01

    Full Text Available . For applications in coastal engineering and also in pavement engineering, the capture of particle shapes as polyhedra rather than clumped spheres is particularly important. The development of a Discrete Element Model applicable to both fields, and to industrial...

  14. Unsteady Transonic Flow Past Airfoils in Rigid Body Motion.

    Science.gov (United States)

    1981-03-01

    number of lower surface coordinates. For ISYM = 1, NL = NU even thouqh no lower surface coordinates are given. NX The number of mesh cells in the...direction of the chord used at the start of the calculation. NX = 0 causes termination of the program. Ny The number of mesh cells in the direction normal...3) 4 LL SY’ieLL L.,C., .C7, li.,-l) CALL SYM L L (-.2 ,C., .14, £PILp., 2) CALL PLCT( C.,...,?) .ALL PLUT C , (I), 1CPCAL"IC (1, ),2) C L j NT1 NUE

  15. Reorientation of Asymmetric Rigid Body Using Two Controls

    Directory of Open Access Journals (Sweden)

    Donghoon Kim

    2013-01-01

    Full Text Available Most spacecrafts are designed to be maneuvered to achieve pointing goals. This is accomplished usually by designing a three-axis control system, which can achieve arbitrary maneuvers, where the goal is to repoint the spacecraft and match a desired angular velocity at the end of the maneuver. New control laws are required, however, if one of the three-axis control actuators fails. This paper explores suboptimal maneuver strategies when only two control torque inputs are available. To handle this underactuated system control problem, the three-axis maneuver strategy is transformed to two successive independent submaneuver strategies. The first maneuver is conducted on one of the available torque axes. Next, the second maneuver is conducted on the torque available plane using two available control torques. However, the resulting control law is more complicated than the general three-axis control law. This is because an optimal switch time needs to be found for determining the end time for the single-axis maneuver or the start time for the second maneuver. Numerical simulation results are presented that compare optimal maneuver strategies for both nominal and failed actuator cases.

  16. Efficiency of wave-driven rigid body rotation toroidal confinement

    Science.gov (United States)

    Rax, J. M.; Gueroult, R.; Fisch, N. J.

    2017-03-01

    The compensation of vertical drifts in toroidal magnetic fields through a wave-driven poloidal rotation is compared with compensation through the wave driven toroidal current generation to support the classical magnetic rotational transform. The advantages and drawbacks associated with the sustainment of a radial electric field are compared with those associated with the sustainment of a poloidal magnetic field both in terms of energy content and power dissipation. The energy content of a radial electric field is found to be smaller than the energy content of a poloidal magnetic field for a similar set of orbits. The wave driven radial electric field generation efficiency is similarly shown, at least in the limit of large aspect ratio, to be larger than the efficiency of wave-driven toroidal current generation.

  17. Hamiltonian Dynamics of Spider-Type Multirotor Rigid Bodies Systems

    International Nuclear Information System (INIS)

    Doroshin, Anton V.

    2010-01-01

    This paper sets out to develop a spider-type multiple-rotor system which can be used for attitude control of spacecraft. The multirotor system contains a large number of rotor-equipped rays, so it was called a 'Spider-type System', also it can be called 'Rotary Hedgehog'. These systems allow using spinups and captures of conjugate rotors to perform compound attitude motion of spacecraft. The paper describes a new method of spacecraft attitude reorientation and new mathematical model of motion in Hamilton form. Hamiltonian dynamics of the system is investigated with the help of Andoyer-Deprit canonical variables. These variables allow obtaining exact solution for hetero- and homoclinic orbits in phase space of the system motion, which are very important for qualitative analysis.

  18. Quaternion Feedback Control for Rigid-body Spacecraft

    DEFF Research Database (Denmark)

    Jensen, Hans-Christian Becker; Wisniewski, Rafal

    2001-01-01

    This paper addresses three-axis attitude control for a Danish spacecraft, Roemer. The algorithm proposed is based on an approximation of the exact feedback linearisation for quaternionic attitude representation. The proposed attitude controller is tested in a simulation study. The environmental...

  19. Analysis of Switched-Rigid Floating Oscillator

    Directory of Open Access Journals (Sweden)

    Prabhakar R. Marur

    2009-01-01

    Full Text Available In explicit finite element simulations, a technique called deformable-to-rigid (D2R switching is used routinely to reduce the computation time. Using the D2R option, the deformable parts in the model can be switched to rigid and reverted back to deformable when needed during the analysis. The time of activation of D2R however influences the overall dynamics of the system being analyzed. In this paper, a theoretical basis for the selection of time of rigid switching based on system energy is established. A floating oscillator problem is investigated for this purpose and closed-form analytical expressions are derived for different phases in rigid switching. The analytical expressions are validated by comparing the theoretical results with numerical computations.

  20. Rigid pricing and rationally inattentive consumer

    Czech Academy of Sciences Publication Activity Database

    Matějka, Filip

    158 B, July (2015), s. 656-678 ISSN 0022-0531 Institutional support: PRVOUK-P23 Keywords : rational inattention * imperfect information * nominal rigidity Subject RIV: AH - Economics Impact factor: 1.097, year: 2015

  1. Rigid pricing and rationally inattentive consumer

    Czech Academy of Sciences Publication Activity Database

    Matějka, Filip

    158 B, July (2015), s. 656-678 ISSN 0022-0531 Institutional support: RVO:67985998 Keywords : rational inattention * imperfect information * nominal rigidity Subject RIV: AH - Economics Impact factor: 1.097, year: 2015

  2. Dieting and unhealthy weight control behaviors during adolescence: associations with 10-year changes in body mass index.

    Science.gov (United States)

    Neumark-Sztainer, Dianne; Wall, Melanie; Story, Mary; Standish, Amber R

    2012-01-01

    Dieting and unhealthy weight control behaviors are common among adolescents and questions exist regarding their long-term effect on weight status. To examine 10-year longitudinal associations between dieting and unhealthy weight control behaviors and changes in body mass index (BMI) from adolescence to young adulthood. A diverse population-based sample of middle school and high school adolescents participating in Project EAT (Eating and Activity in Teens and Young Adults) was followed up for 10 years. Participants (N = 1,902) completed surveys in 1998-1999 (Project EAT-I), 2003-2004 (Project EAT-II), and 2008-2009 (Project EAT-III). Dieting and unhealthy weight control behaviors at Time 1 and Time 2 were used to predict 10-year changes in BMI at Time 3, adjusting for sociodemographic characteristics and Time 1 BMI. Dieting and unhealthy weight control behaviors at both Time 1 and Time 2 predicted greater BMI increases at Time 3 in males and females, as compared with no use of these behaviors. For example, females using unhealthy weight control behaviors at both Time 1 and Time 2 increased their BMI by 4.63 units as compared with 2.29 units in females not using these behaviors (p meals and reporting eating very little (females and males), use of food substitutes (males), and use of diet pills (females). Findings clearly indicate that dieting and unhealthy weight control behaviors, as reported by adolescents, predict significant weight gain over time. Copyright © 2012 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  3. Cyberbullying Victimization as a Predictor of Cyberbullying Perpetration, Body Image Dissatisfaction, Healthy Eating and Dieting Behaviors, and Life Satisfaction.

    Science.gov (United States)

    Ramos Salazar, Leslie

    2017-08-01

    Cyberbullying victimization and perpetration continues to be a serious public health, criminal justice, victimology, and educational problem in middle schools in the United States. Adolescents are at a higher risk of experiencing cyberbullying as a victim and/or as a bully given the frequency of their use of the Internet via social networking sites such as Facebook and mobile devices such as cell phones and tablets. To address this important problem, the purpose of this investigation was to examine cyberbullying victimization through communication technology as a predictor of cyberbullying perpetration, body image, healthy eating and dieting behaviors, and life satisfaction of sixth-, seventh-, and eighth-grade-level middle school students. The World Health Organization recruited participants by using a Health Behavior in School-Aged Children (HBSC) survey. In this in-class questionnaire, 6,944 middle school students were asked about their cyberbullying experiences as a victim and as a bully via Internet, email, and mobile communication technologies to obtain their evaluations of their body image, eating and dieting habits, and perceptions of life satisfaction. After controlling for demographic factors such as sex, age, and class level, this study found that cyberbullying victimization was a predictor of cyberbullying perpetration, body image dissatisfaction, dieting behaviors, and life satisfaction. However, this study did not find a correlation between cyberbullying victimization and students' healthy eating behaviors. This study also discussed each of the findings in the context of previous research findings. In addition, the study provides the strengths, limitations, and future directions for the future examination of cyberbullying victimization in middle schools.

  4. Weight self-regulation process in adolescence: the relationship between control weight attitudes, behaviors and body weight status

    Directory of Open Access Journals (Sweden)

    Jordi ePich

    2015-05-01

    Full Text Available Adolescents’ self-control weight behaviors were assessed (n= 1961; 12-17 years old; 2007-2008 in the Balearic Islands, Spain. The study analyzed the relationships between body weight status, body image and self-weight concern, and actual attempts to lose weight by restrained eating and/or increased exercising. In terms of regulatory focus theory (RFT, we considered that efforts to lose or to maintain weight (successful or failed would be motivated either by a promotion focus (to show an attractive body, a prevention focus (to avoid social rejection of fatness, or both. Results showed that 41% of overweight boys and 25% of obese boys stated that they had never made any attempt to lose weight, and 13% and 4% in females. Around half of overweight boys and around a quarter of obese boys stated that they were Not at all concerned about weight gain, and girls’ percentages decreased to 13% and 11% respectively. By contrast 57% of normal weight girls monitored their weight and stated that they had tried to slim at least once. Weight self-regulation in females attempted to combine diet and exercise, while boys relied almost exclusively on exercise. Apparent lack of consciousness of body weight status among overweight boys, and more important, subsequent absence of behaviors to reduce their weight clearly challenges efforts to prevent obesity. We argue that several causes may be involved in this outcome, including unconscious emotional (self-defense and cognitive (dissonance mechanisms driven by perceived social stigmatization of obesity. The active participation of social values of male and female body image (strong vs. pretty and the existence of social habituation to overweight are suggested. A better knowledge of psychosocial mechanisms underlying adolescent weight self-control may improve obesity epidemics.

  5. Two Back Stress Hardening Models in Rate Independent Rigid Plastic Deformation

    Science.gov (United States)

    Yun, Su-Jin

    In the present work, the constitutive relations based on the combination of two back stresses are developed using the Armstrong-Frederick, Phillips and Ziegler’s type hardening rules. Various evolutions of the kinematic hardening parameter can be obtained by means of a simple combination of back stress rate using the rule of mixtures. Thus, a wide range of plastic deformation behavior can be depicted depending on the dominant back stress evolution. The ultimate back stress is also determined for the present combined kinematic hardening models. Since a kinematic hardening rule is assumed in the finite deformation regime, the stress rate is co-rotated with respect to the spin of substructure obtained by incorporating the plastic spin concept. A comparison of the various co-rotational rates is also included. Assuming rigid plasticity, the continuum body consists of the elastic deformation zone and the plastic deformation zone to form a hybrid finite element formulation. Then, the plastic deformation behavior is investigated under various loading conditions with an assumption of the J2 deformation theory. The plastic deformation localization turns out to be strongly dependent on the description of back stress evolution and its associated hardening parameters. The analysis for the shear deformation with fixed boundaries is carried out to examine the deformation localization behavior and the evolution of state variables.

  6. Crack identification for rigid pavements using unmanned aerial vehicles

    Science.gov (United States)

    Bahaddin Ersoz, Ahmet; Pekcan, Onur; Teke, Turker

    2017-09-01

    Pavement condition assessment is an essential piece of modern pavement management systems as rehabilitation strategies are planned based upon its outcomes. For proper evaluation of existing pavements, they must be continuously and effectively monitored using practical means. Conventionally, truck-based pavement monitoring systems have been in-use in assessing the remaining life of in-service pavements. Although such systems produce accurate results, their use can be expensive and data processing can be time consuming, which make them infeasible considering the demand for quick pavement evaluation. To overcome such problems, Unmanned Aerial Vehicles (UAVs) can be used as an alternative as they are relatively cheaper and easier-to-use. In this study, we propose a UAV based pavement crack identification system for monitoring rigid pavements’ existing conditions. The system consists of recently introduced image processing algorithms used together with conventional machine learning techniques, both of which are used to perform detection of cracks on rigid pavements’ surface and their classification. Through image processing, the distinct features of labelled crack bodies are first obtained from the UAV based images and then used for training of a Support Vector Machine (SVM) model. The performance of the developed SVM model was assessed with a field study performed along a rigid pavement exposed to low traffic and serious temperature changes. Available cracks were classified using the UAV based system and obtained results indicate it ensures a good alternative solution for pavement monitoring applications.

  7. Associations among Work and Family Health Climate, Health Behaviors, Work Schedule and Body Weight

    Science.gov (United States)

    Buden, Jennifer C.; Dugan, Alicia G.; Faghri, Pouran D.; Huedo-Medina, Tania B.; Namazi, Sara; Cherniack, Martin G.

    2017-01-01

    Objectives Correctional employees exhibit elevated obesity rates. This study examines interrelations among health behaviors, health climate, BMI, and work schedule. Methods Using survey results from correctional supervisors (n=157), mediation and moderated-mediation analyses were performed to examine how health behaviors explain relationships between obesity, work health climate (WHC) and family health climate (FHC), and work schedule. Results Over 85% of the sample was overweight/obese (mean BMI=30.20). Higher WHC and FHC were associated with lower BMI, mediated by nutrition and physical activity. The interaction effect between health behavior and work schedule revealed a protective effect on BMI. Overtime shiftwork may share a relationship with BMI. Conclusions Findings may have implications for reexamining organizational policies on maximum weekly overtime in corrections. They provide direction for targeted obesity interventions that encourage a supportive FHC and promote healthy behaviors among supervisors working overtime. PMID:28471768

  8. Flexible and rigid cystoscopy in women.

    Science.gov (United States)

    Gee, Jason R; Waterman, Bradley J; Jarrard, David F; Hedican, Sean P; Bruskewitz, Reginald C; Nakada, Stephen Y

    2009-01-01

    Previous studies have evaluated the tolerability of rigid versus flexible cystoscopy in men. Similar studies, however, have not been performed in women. We sought to determine whether office-based flexible cystoscopy was better tolerated than rigid cystoscopy in women. Following full IRB approval, women were prospectively randomized in a single-blind manner. Patients were randomized to flexible or rigid cystoscopy and draped in the lithotomy position to maintain blinding of the study. Questionnaires evaluated discomfort before, during, and after cystoscopy. Thirty-six women were randomized to flexible (18) or rigid (18) cystoscopy. Indications were surveillance (16), hematuria (15), recurrent UTIs (2), voiding dysfunction (1), and other (2). All questionnaires were returned by 31/36 women. Using a 10-point visual analog scale (VAS), median discomfort during the procedure for flexible and rigid cystoscopy were 1.4 and 1.8, respectively, in patients perceiving pain. Median recalled pain 1 week later was similar at 0.8 and 1.15, respectively. None of these differences were statistically significant. Flexible and rigid cystoscopy are well tolerated in women. Discomfort during and after the procedure is minimal in both groups. Urologists should perform either procedure in women based on their preference and skill level.

  9. Growth curve and diet density affect eating motivation, behavior, and body composition of broiler breeders during rearing.

    Science.gov (United States)

    de Los Mozos, J; García-Ruiz, A I; den Hartog, L A; Villamide, M J

    2017-08-01

    The aim of this work has been to assess the effect of diet density [control (CON) or 15% diluted (DIL)] and growth curve [recommended by the genetic line (RBW) or 15% heavier (HBW)] and their interaction on BW uniformity, feeding motivation, behavior, and body composition of broiler breeder pullets. A total of 3,000 one-day-old female breeders Ross 308, distributed in 20 pens, was randomly assigned to each treatment. Feed allowance was weekly adjusted to reach the desired BW. Feed was provided as pelleted (zero to 3 wk) and crumble (4 to 19 wk). Time eating was measured at 7, 11, and 19 weeks. A feeding rate test was performed after 11 weeks. Behavior was observed at 9 and 15 wk, by visual scan. At 6, 13, and 19 wk of age, one bird/pen was slaughtered for weighing different organs and analyzing the composition of empty whole bodies. Treatments did not affect BW uniformity; relative weights of the ovary, oviduct, or gizzard; or protein content of empty BW. Time eating varied with the growth curve at 19 wk (P motivation. Behavior was affected by the age and by the time of the d measured, but it did not change with the treatments. Birds spent most time pecking objects (50%), feeding (28%), and drinking (17%). Pullets fed DIL had 8% lower breast yield at different ages and higher empty digestive tracts at 6 weeks. Body composition varied with age; fat content increased from 12.7 to 15.9 to 19.8% for 6, 13, and 19 wk, respectively. The lowest body fat was observed for RBW pullets fed DIL (P = 0.003) at 19 weeks. Feeding DIL diets to HBW pullets could be done to increase the time spent eating and reduce their feeling of hunger without negative effects on body composition. However, its influence on behavior and BW uniformity was not proved. © The Author 2017. Published by Oxford University Press on behalf of Poultry Science Association.

  10. Nutrition quality, body size and two components of mating behavior in Drosophila melanogaster.

    Science.gov (United States)

    Pavković-Lucić, Sofija; Kekić, Vladimir

    2010-01-01

    Two components of mating behavior, mating latency and duration of copulation, were investigated in Drosophila melanogaster males from three different "nutritional" strains, reared for more than 35 generations on banana, tomato and cornmeal-agar-yeast substrates. Males from different strains did not differ according to mating latency and duration of copulation. Also, the sizes of males from different strains did not contribute to these behavioral traits.

  11. Parental Misperception of Their Child's Body Weight Status Impedes the Assessment of the Child's Lifestyle Behaviors

    Directory of Open Access Journals (Sweden)

    Marie-Eve Mathieu

    2010-01-01

    Full Text Available Objectives. To examine if distinct characteristics are associated with parental misclassification of underweight (UW, normal weight (NW, and overweight or obese (OWOB children and the implications of misclassification on the parental evaluation of the child's lifestyle habits. Methods. Cross-sectional analysis (2004 sample of the Quebec Longitudinal Study of Child Development (1998–2010 (n=1,125. Results. 16%, 55%, and 77% of NW, UW and OWOB children were perceived inaccurately, respectively. Misperception was significantly higher in nonimmigrant parents of UW children, in highly educated parents of NW children and in NW and OWOB children with lower BMI percentiles. Erroneous body weight status identification impedes the evaluation of eating habits of all children as well as physical activity and fitness levels of UW and OWOB children. Conclusion. Parental misclassification of the child's body weight status and lifestyle habits constitutes an unfavorable context for healthy body weight management.

  12. Ontogenetic behavior and dispersal of Sacramento River white sturgeon, Acipenser transmontanus, with a note on body color

    Science.gov (United States)

    Kynard, B.; Parker, E.

    2005-01-01

    We studied Sacramento River white sturgeon, Acipenser transmontanus, in the laboratory to develop a conceptual model of ontogenetic behavior and provide insight into probable behavior of wild sturgeon. After hatching, free embryos initiated a low intensity, brief downstream dispersal during which fish swam near the bottom and were photonegative. The weak, short dispersal style and behavior of white sturgeon free embryos contrasts greatly with the intense, long dispersal style and behavior (photopositive and swimming far above the bottom) of dispersing free embryos of other sturgeon species. If spawned eggs are concentrated within a few kilometers downstream of a spawning site, the adaptive significance of the free embryo dispersal is likely to move fish away from the egg deposition site to avoid predation and reduce fish density prior to feeding. Larvae foraged on the open bottom, swam innate fish dispersal and post-dispersal rearing habitat, which is now highly altered by damming and reservoirs. Sacramento River white sturgeon has a two-step downstream dispersal by the free embryo and juvenile life intervals. Diel activity of all life intervals peaked at night, whether fish were dispersing or foraging. Nocturnal behavior is likely a response to predation, which occurs during both activities. An intense black-tail body color was present on foraging larvae, but was weak or absent on the two life intervals that disperse. Black-tail color may be an adaptation for avoiding predation, signaling among aggregated larvae, or both, but not for dispersal. ?? Springer 2005.

  13. Pretty as a Princess: Longitudinal Effects of Engagement With Disney Princesses on Gender Stereotypes, Body Esteem, and Prosocial Behavior in Children.

    Science.gov (United States)

    Coyne, Sarah M; Linder, Jennifer Ruh; Rasmussen, Eric E; Nelson, David A; Birkbeck, Victoria

    2016-11-01

    This study examined level of engagement with Disney Princess media/products as it relates to gender-stereotypical behavior, body esteem (i.e. body image), and prosocial behavior during early childhood. Participants consisted of 198 children (M age  = 58 months), who were tested at two time points (approximately 1 year apart). Data consisted of parent and teacher reports, and child observations in a toy preference task. Longitudinal results revealed that Disney Princess engagement was associated with more female gender-stereotypical behavior 1 year later, even after controlling for initial levels of gender-stereotypical behavior. Parental mediation strengthened associations between princess engagement and adherence to female gender-stereotypical behavior for both girls and boys, and for body esteem and prosocial behavior for boys only. © 2016 The Authors. Child Development © 2016 Society for Research in Child Development, Inc.

  14. Association of fathers' feeding practices and feeding style on preschool age children's diet quality, eating behavior and body mass index.

    Science.gov (United States)

    Vollmer, Rachel L; Adamsons, Kari; Foster, Jaime S; Mobley, Amy R

    2015-06-01

    The associations of parental feeding practices and feeding style with childhood obesity have gained more attention in the literature recently; however, fathers are rarely included within these studies. The aim of this research was to determine the relationship of paternal feeding practices on child diet quality, weight status, and eating behavior, and the moderating effect of paternal feeding style on these relationships in preschool age children. This study included a one-time, one-on-one interview with biological fathers of preschoolers (n = 150) to assess feeding practices (Child Feeding Questionnaire), feeding style (Caregiver Feeding Style Questionnaire), child eating behaviors (Child Eating Behavior Questionnaire), and diet quality (24 hour recall, Healthy Eating Index). Height and weight for each father and child were also measured and Body Mass Index (BMI) or BMI z-score calculated. Linear regression was used to test the relationship between paternal feeding practices, style and child diet quality and/or body weight. Overall, the findings revealed that a father's feeding practices and feeding style are not associated with children's diet quality or weight status. However, child eating behaviors are associated with child BMI z-score and these relationships are moderated by paternal feeding practices. For example, child satiety responsiveness is inversely (β = -.421, p = 0.031) associated with child BMI z-score only if paternal restriction scores are high. This relationship is not significant when paternal restriction scores are low (β = -.200, p = 0.448). These results suggest that some child appetitive traits may be related to child weight status when exposed to certain paternal feeding practices. Future studies should consider the inclusion of fathers as their feeding practices and feeding style may be related to a child's eating behavior. Copyright © 2015 Elsevier Ltd. All rights reserved.

  15. Variation in foraging behavior and body mass in broods of Emperor Geese (Chen canagica): Evidence for interspecific density dependence

    Science.gov (United States)

    Schmutz, J.A.; Laing, K.K.

    2002-01-01

    Broods of geese spend time feeding according to availability and quality of food plants, subject to inherent foraging and digestive constraints. We studied behavioral patterns of broods of Emperor Geese (Chen canagica) on the Yukon–Kuskokwim Delta, Alaska, and examined how feeding and alert behavior varied in relation to habitat and goose density. During 1994–1996, time spent feeding by Emperor Goose goslings and adult females was positively related to multispecies goose densities near observation blinds, and not to just Emperor Goose density. Similarly, body mass of Emperor Goose goslings was more strongly related (negatively) to multispecies goose densities than intraspecific densities. A grazing experiment in 1995 indicated that most above ground primary production by Carex subspathacea, a preferred food plant, was consumed by grazing geese. Those results demonstrate that interspecific competition for food occurred, with greatest support for goslings whose behavioral repertoire is limited primarily to feeding, digesting, and resting. Although the more abundant Cackling Canada Geese (Branta canadensis minima) differed from Emperor Geese in their preferred use of habitats during brooding rearing (Schmutz 2001), the two species occurred in equal abundance in habitats preferred by Emperor Goose broods. Thus, Cackling Canada Geese were a numerically significant competitor with Emperor Geese. Comparing these results to an earlier study, time spent feeding by goslings, adult females, and adult males were greater during 1993–1996 than during 1985–1986. During the interval between those studies, densities of Cackling Canada Geese increased two to three times whereas Emperor Goose numbers remained approximately stable, which implies that interspecific competition affected foraging behavior over a long time period. These density-dependent changes in foraging behavior and body mass indicate that interspecific competition affects nutrient acquisition and gosling

  16. Which Type of Sedentary Behavior Intervention is More Effective at Reducing Body Mass Index in Children? A Meta-Analytic Review

    OpenAIRE

    Liao, Yue; Liao, Jingjing; Durand, Casey P.; Dunton, Genevieve F

    2013-01-01

    Sedentary behavior is emerging as an independent risk factor for pediatric obesity. Some evidence suggests that limiting sedentary behavior alone could be effective in reducing body mass index (BMI) in children. However, whether adding physical activity and diet-focused components to sedentary behavior reduction interventions could lead to an additive effect is unclear. This meta-analysis aims to assess the overall effect size of sedentary behavior interventions on BMI reduction, and to compa...

  17. Bidirectional associations between activity-related parenting practices, and child physical activity, sedentary screen-based behavior and body mass index: a longitudinal analysis

    OpenAIRE

    Sleddens, Ester F. C.; Gubbels, Jessica S.; Kremers, Stef P. J.; van der Plas, Eline; Thijs, Carel

    2017-01-01

    Background It has been generally assumed that activity-related parenting practices influence children?s activity behavior and weight status. However, vice versa parents may also change their parenting behaviors in response to their perceptions of their child?s activity behavior and weight status. This study examined the bidirectional relationships between activity-related parenting practices, and physical activity, sedentary screen-based behavior, and body mass index (BMI) between children?s ...

  18. Ontogenetic behavior, migration, and social behavior of pallid sturgeon, Scaphirhynchus albus, and shovelnose sturgeon, S. platorynchus, with notes on the adaptive significance of body color

    Science.gov (United States)

    Kynard, B.; Henyey, E.; Horgan, M.

    2002-01-01

    We conducted laboratory studies on the ontogenetic behavior of free embryos (first life interval after hatching) and larvae (first feeding interval) of pallid and shovelnose sturgeon. Migration styles of both species were similar for timing of migration (initiation by embryos on day 0 after hatching and cessation by larvae on days 12-13 at 236-243 cumulative temperature degree units), migration distance (about 13 km), life interval when most distance was moved (embryo), and diel behavior of embryos (diurnal). However, the species differed for two behaviors: movement characteristics of embryos (peak movement rate of pallid sturgeon was only one-half the peak rate of shovelnose sturgeon, but pallid sturgeon continued the lower rate for twice as long) and diel behavior of larvae (pallid sturgeon were diurnal and shovelnose sturgeon were nocturnal). Thus, the species used different methods to move the same distance. Migrating as poorly developed embryos suggests a migration style to avoid predation at the spawning site, but moving from spawning habitat to rearing habitat before first feeding could also be important. Migrants of both species preferred bright habitat (high illumination intensity and white substrate), a behavioral preference that may characterize the migrants of many species of sturgeon. Both species were remarkably similar for swimming height above the bottom by age, and day 7 and older migrants may swim far above the bottom and move far downstream. A migration of 12 or 13 days will probably not distribute larvae throughout the population's range, so an older life interval likely initiates a second longer downstream migration (2-step migration). By day 2, individuals of both species were a black-tail phenotype (light grey body with a black-tail that moved conspicuously during swimming). Aggregation behavior suggests that black-tail is a visual signal used for group cohesion.

  19. Experimental consequences of predicted charge rigidity of superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Hirsch, J.E., E-mail: jhirsch@ucsd.edu [Department of Physics, University of California, San Diego, La Jolla, CA 92093-0319 (United States)

    2012-08-15

    The theory of hole superconductivity predicts that in superconductors the charged superfluid is about a million times more rigid than the normal electron fluid. We point out that this physics should give rise to large changes in the bulk and surface plasmon dispersion relations of metals entering the superconducting state, that have not yet been experimentally detected and would be in stark contradiction with the expected behavior within conventional BCS-London theory. We also propose that this explains the puzzling experimental observations of Avramenko et al. on electron sound propagation in superconductors and the puzzling experiments of de Heer et al. detecting large electric dipole moments in small metal clusters, as well as the Tao effect on aggregation of superconducting microparticles in an electric field. Associated with the enhanced charge rigidity is a large increase in the electric screening length of superconductors at low temperatures that has not yet been experimentally detected. The physical origin of the enhanced charge rigidity and its relation to other aspects of the theory of hole superconductivity is discussed.

  20. Body weight manipulation, reinforcement value and choice between sucrose and wheel running: a behavioral economic analysis.

    Science.gov (United States)

    Belke, Terry W; Pierce, W David

    2009-02-01

    Twelve female Long-Evans rats were exposed to concurrent variable (VR) ratio schedules of sucrose and wheel-running reinforcement (Sucrose VR 10 Wheel VR 10; Sucrose VR 5 Wheel VR 20; Sucrose VR 20 Wheel VR 5) with predetermined budgets (number of responses). The allocation of lever pressing to the sucrose and wheel-running alternatives was assessed at high and low body weights. Results showed that wheel-running rate and lever-pressing rates for sucrose and wheel running increased, but the choice of wheel running decreased at the low body weight. A regression analysis of relative consumption as a function of relative price showed that consumption shifted toward sucrose and interacted with price differences in a manner consistent with increased substitutability. Demand curves showed that demand for sucrose became less elastic while demand for wheel running became more elastic at the low body weight. These findings reflect an increase in the difference in relative value of sucrose and wheel running as body weight decreased. Discussion focuses on the limitations of response rates as measures of reinforcement value. In addition, we address the commonalities between matching and demand curve equations for the analysis of changes in relative reinforcement value.

  1. Maternal behaviors and restrained eating and body dissatisfaction in young children

    NARCIS (Netherlands)

    Anschutz, Doeschka J; Kanters, Linda J A; van Strien, Tatjana; Vermulst, Ad A; Engels, Rutger C M E

    OBJECTIVE: The present study aimed at testing the relations between maternal weight concern and maternal encouragement to be thin as perceived by the child, and restraint and body dissatisfaction in young children. METHOD: Cross-sectional data were collected among 501 children (aged 7-10), using

  2. Body Talk: A School-based Group Intervention for Working with Disordered Eating Behaviors.

    Science.gov (United States)

    Daigneault, Susan Dahlgren

    2000-01-01

    Describes a school-based group intervention designed to address issues of body image, self-esteem, weight, and eating disturbances. This 10-session group provides female high school students with opportunities to explore their concerns about relationships, appearance, and what it means to be female. Provides descriptions of narrative techniques…

  3. Developmental Emergence of Self-Referential and Inhibition Mechanisms of Body Movements Underling Felicitous Behaviors

    Science.gov (United States)

    Watanabe, Hama; Homae, Fumitaka; Taga, Gentaro

    2011-01-01

    In young infants, activation or inhibition of body movements on perception of environmental events is important to enable them to act on the world or understand the world. To reveal the development of this ability, we observed movement patterns in all four limbs under the two experimental conditions. Infants assigned to the interaction condition…

  4. Habitat deterioration affects antipredatory behavior, body condition, and parasite load of female Psammodromus algirus lizards

    NARCIS (Netherlands)

    Amo de Paz, L.; López, P.; Martín, J.

    2007-01-01

    Deforestation may increase predation risk for prey because it may make prey more conspicuous and limit the number of refuges suitable to avoid predators. Therefore, prey may need to increase the magnitude of escape responses. However, excessive antipredatory effort might lead to a loss of body mass

  5. Primary School Children's Health Behaviors, Attitudes, and Body Mass Index After a 10-Week Lifestyle Intervention With Follow-Up.

    Science.gov (United States)

    Brown, Elise C; Buchan, Duncan S; Drignei, Dorin; Wyatt, Frank B; Kilgore, Lon; Cavana, Jonathan; Baker, Julien S

    2018-01-01

    Background: Given the current global child obesity epidemic, testing the effectiveness of interventions in reducing obesity and its influencers is paramount. The purpose of this study was to determine immediate and long-term changes in body mass index and psychosocial variables following a 10-week lifestyle intervention. Methods: Seven hundred and seventy participants (8.75 ± 0.98 years of age, 379 boys and 391 girls) took part in the study. Participants had height, weight, and psychosocial questionnaires assessed at pre- and post-control, pre- and post-intervention, and 6-months post-intervention. Participants completed a weekly 10-week intervention consisting of healthy eating and physical activity education, physical activity, parental involvement, and behavior change techniques. Regression models were fit with correlated errors where the correlation occurred only between time points, not between subjects, and the nesting effects of school and area deprivation were controlled. Results: Regression models revealed a significant decrease in body mass index from pre- to post-intervention of 0.8512 kg/m 2 ( P = 0.0182). No Changes in body mass index occurred from post-intervention to 6-month follow-up ( P = 0.5446). The psychosocial variables did not significantly change. Conclusions: This lifestyle intervention may be an effective means for improving body mass index in primary school children in the short-term if the duration of the intervention is increased, but these changes may not be sustained without on-going support.

  6. Therapeutic rigid bronchoscopy at a tertiary care center in North India: Initial experience and systematic review of Indian literature

    Directory of Open Access Journals (Sweden)

    Karan Madan

    2014-01-01

    Full Text Available Background and Aim: Rigid bronchoscopy is often an indispensable procedure in the therapeutic management of a wide variety of tracheobronchial disorders. However, it is performed at only a few centers in adult patients in India. Herein, we report our initial 1-year experience with this procedure. Materials and Methods: A prospective observational study on the indications, outcomes, and safety of various rigid bronchoscopy procedures performed between November 2009 and October 2010. Improvement in dyspnea, cough, and the overall quality of life was recorded on a visual analog scale from 0 to 100 mm. A systematic review of PubMed was performed to identify studies reporting the use of rigid bronchoscopy from India. Results: Thirty-eight rigid bronchoscopies (50 procedures were performed in 19 patients during the study period. The commonest indication was benign tracheal stenosis followed by central airway tumor, and the procedures performed were rigid bronchoplasty, tumor debulking, and stent placement. The median procedure duration was 45 (range, 30-65 min. There was significant improvement in quality of life associated with therapeutic rigid bronchoscopy. Minor procedural complications were encountered in 18 bronchoscopies, and there was no procedural mortality. The systematic review identified 15 studies, all on the role of rigid bronchoscopy in foreign body removal. Conclusions: Rigid bronchoscopy is a safe and effective modality for treatment of a variety of tracheobronchial disorders. There is a dire need of rigid bronchoscopy training at teaching hospitals in India.

  7. Overestimation of own body weights in female university students: associations with lifestyles, weight control behaviors and depression

    OpenAIRE

    Kim, Miso; Lee, Hongmie

    2010-01-01

    The study aimed to analyze the lifestyles, weight control behavior, dietary habits, and depression of female university students. The subjects were 532 students from 8 universities located in 4 provinces in Korea. According to percent ideal body weight, 33 (6.4%), 181 (34.0%), 283 (53.2%), 22 (4.1%) and 13 (2.5%) were severely underweight, underweight, normal, overweight and obese, respectively, based on self-reported height and weight. As much as 64.1% and only 2.4%, respectively, overestima...

  8. Nonlinear complex dynamics and Keynesian rigidity: A short introduction

    Science.gov (United States)

    Jovero, Edgardo

    2005-09-01

    The topic of this paper is to show that the greater acceptance and intense use of complex nonlinear dynamics in macroeconomics makes sense only within the neoKeynesian tradition. An example is presented regarding the behavior of an open-economy two-sector growth model endowed with Keynesian rigidity. The Keynesian view that structural instability globally exists in the aggregate economy is put forward, and therefore the need arises for policy to alleviate this instability in the form of dampened fluctuations is presented as an alternative view for macroeconomic theorizing.

  9. Sex-Related Online Behaviors and Adolescents’ Body and Sexual Self-Perceptions

    NARCIS (Netherlands)

    Doornwaard, Suzan; Bickham, D.S.; Rich, Michael; Vanwesenbeeck, W.M.A.; van den Eijnden, Regina; ter Bogt, Tom

    2014-01-01

    BACKGROUND AND OBJECTIVE: This study investigated: (1) the prevalence and development of 2 receptive (sexually explicit Internet material [SEIM] use and sexual information seeking) and 2 interactive (cybersex and general social networking site [SNS] use) online behaviors in adolescence; (2) whether

  10. Influence of step-height and body mass on gastrocnemius muscle fascicle behavior during stair ascent.

    NARCIS (Netherlands)

    Spanjaard, M.; Reeves, N.D.; van Dieen, J.H.; Baltzopoulos, V.; Maganaris, C.N.

    2008-01-01

    To better understand the role of the ankle plantar flexor muscles in stair negotiation, we examined the effects of manipulation of kinematic and kinetic constraints on the behavior of the gastrocnemius medialis (GM) muscle during stair ascent. Ten subjects ascended a four-step staircase at four

  11. From the body punishment to the good setting of behaviors in education

    Directory of Open Access Journals (Sweden)

    Juan Illicachi Guzñay

    2017-01-01

    Full Text Available Whereas Education is a prime area to study the exercise of power, the article analyzes the way power operates discipline which is exercised over the bodies of individuals and intended to watch them, control them and train them in order to make them docile and useful- and biopower which is exercised in the collective body of the people and feeds on the knowledge that are generated from the population itself. And the way how are you forms of power in the monocultural educational field was challenged and sismada for bilingual intercultural education: first, because the intercultural institutions emerges in opposition to the hegemonic education and as a banner of political struggle, epistemic Ecuadorian indigenous movement. Second, because it is in the insurrection and return knowing subject. Although intercultural bilingual education, sometimes also continues to play the same forms of constitution of subjects through a number of practices of knowledge-power.

  12. Sports and health : the influence of motivational orientation on body image and doping behaviors

    OpenAIRE

    Lugo, Ric

    2009-01-01

    Health is much talked about topic in today’s society, likewise with sports. Sports and exercise have been introduced has an entranceway to healthier living styles. But increasing reports about how athletes and exercisers use doping agents that are contrary to health beliefs and recommendations from the World Anti-Doping Agency are found in the media. Body Image and eating disorders has also seen a rise in media reports, especially in the sporting world. Athletes are now models and are visible...

  13. Path Analysis of Campus Walkability/Bikeability and College Students' Physical Activity Attitudes, Behaviors, and Body Mass Index.

    Science.gov (United States)

    Horacek, Tanya M; Dede Yildirim, E; Kattelmann, K; Brown, O; Byrd-Bredbenner, C; Colby, S; Greene, G; Hoerr, S; Kidd, T; Koenings, M M; Morrell, J; Olfert, M D; Phillips, B; Shelnutt, K; White, A

    2018-03-01

    The purpose of this study was to assess the relationship between the walkability/bikeability of college campuses and students' body mass index (BMI) with student physical activity (PA) attitudes and behaviors as potential mediators. Cross-sectional. Thirteen university campuses. A total of 1384 student participants. Walkability/bikeability environmental score (ES): 12-item audit assessed an average of 44 path segments per campus. Students were measured for height and weight and completed online surveys. Physical activity stage of change/behavior intentions were assessed using the transtheoretical model. The Cognitive Behavioral Physical Activity Questionnaire assessed outcome expectations, self-regulation, and personal barriers. International Physical Activity Questionnaire assessed walking-, moderate-, and vigorous-intensity PA. Descriptive statistics, zero-order correlations, and path analysis with maximum likelihood estimation. The overall model fit was good with χ 2 of 171.388 ( df = 18), P walkability/bikeability ES and BMI (β = -.085) and positive association between personal barriers and BMI (β = .134). Walkability/bikeability ES was positively associated with walking-intensity PA (β = .010). Self-regulation was positively associated with moderate-intensity PA (β = .213), which, in turn, was negatively associated with BMI (β = -.057). The ease of walking and biking on a campus was related to college students' walking behavior and their BMI. Students' PA behavioral intentions were associated with moderate PA and lower BMI. These results provide evidence to focus on policies and structural supports for walkable/bikeable environments to supplement and enhance interventions encouraging individual behavior change for PA and weight management.

  14. Cyclic delamination behavior of plasma-sprayed hydroxyapatite coating on Ti-6Al-4V substrates in simulated body fluid.

    Science.gov (United States)

    Otsuka, Yuichi; Kawaguchi, Hayato; Mutoh, Yoshiharu

    2016-10-01

    This study aimed to clarify the effect of a simulated body fluid (SBF) on the cyclic delamination behavior of a plasma-sprayed hydroxapatite (HAp) coating. A HAp coating is deposited on the surfaces of surgical metallic materials in order to enhance the bond between human bone and such surfaces. However, the HAp coating is susceptible to delamination by cyclic loading from the patient's gait. Although hip joints are subjected to both positive and negative moments, only the effects of tensile bending stresses on vertical crack propagation behavior have been investigated. Thus, the cyclic delamination behavior of a HAp coating was observed at the stress ratio R=-1 in order to determine the effects of tensile/compressive loading on the delamination behavior. The delamination growth rate increased with SBF immersion, which decreased the delamination life. Raman spectroscopy analysis revealed that the selective phase dissolution in the HAp coating was promoted at interfaces. Finite element analysis revealed that the energy release rate Gmax showed a positive value even in cases with compressive loading, which is a driving force for the delamination of a HAp coating. A prediction model for the delamination growth life was developed that combines a fracture mechanics parameter with the assumed stress-dependent dissolution rate. The predicted delamination life matched the experimental data well in cases of lower stress amplitudes with SBF. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. Changes in physiological and behavioral parameters of preterm infants undergoing body hygiene: a systematic review

    Directory of Open Access Journals (Sweden)

    Patrícia de Freitas

    2014-08-01

    Full Text Available Objective To verify the effect of bathing on the body temperature of preterm infants (PTI. Method Systematic review conducted in the following bibliographic electronic sources: Biblioteca Virtual em Saúde/Lilacs (BVS, Cumulated Index of Nursing and Allied Health Literature (CINAHL, Cochrane Library, Google Scholar, PubMed, SCOPUS and Web of Science, using a combination of search terms, keywords and free terms. The review question was adjusted to the PICO acronym (Patient/population, Intervention, Control/comparative intervention, Outcome. The selected publications were evaluated according to levels of evidence and grades of recommendation for efficacy/effectiveness studies, as established by the Joanna Briggs Institute. Results Eight hundred and twenty four (824 publications were identified and four studies met the inclusion criteria, of which three analyzed the effect of sponge baths and the effect of immersion baths. Conclusion Sponge baths showed a statistically significant drop in body temperature, while in immersion baths the body temperature remained stable, although they studied late preterm infants.

  16. Changes in physiological and behavioral parameters of preterm infants undergoing body hygiene: a systematic review.

    Science.gov (United States)

    Freitas, Patrícia de; Marques, Silvia Rezende; Alves, Taisy Bezerra; Takahashi, Juliana; Kimura, Amélia Fumiko

    2014-08-01

    Objective To verify the effect of bathing on the body temperature of preterm infants (PTI). Method Systematic review conducted in the following bibliographic electronic sources: Biblioteca Virtual em Saúde/Lilacs (BVS), Cumulated Index of Nursing and Allied Health Literature (CINAHL), Cochrane Library, Google Scholar, PubMed, SCOPUS and Web of Science, using a combination of search terms, keywords and free terms. The review question was adjusted to the PICO acronym (Patient/population, Intervention, Control/comparative intervention, Outcome). The selected publications were evaluated according to levels of evidence and grades of recommendation for efficacy/effectiveness studies, as established by the Joanna Briggs Institute. Results Eight hundred and twenty four (824) publications were identified and four studies met the inclusion criteria, of which three analyzed the effect of sponge baths and the effect of immersion baths. Conclusion Sponge baths showed a statistically significant drop in body temperature, while in immersion baths the body temperature remained stable, although they studied late preterm infants.

  17. Simulated body temperature rhythms reveal the phase-shifting behavior and plasticity of mammalian circadian oscillators

    Science.gov (United States)

    Saini, Camille; Morf, Jörg; Stratmann, Markus; Gos, Pascal; Schibler, Ueli

    2012-01-01

    The circadian pacemaker in the suprachiasmatic nuclei (SCN) of the hypothalamus maintains phase coherence in peripheral cells through metabolic, neuronal, and humoral signaling pathways. Here, we investigated the role of daily body temperature fluctuations as possible systemic cues in the resetting of peripheral oscillators. Using precise temperature devices in conjunction with real-time monitoring of the bioluminescence produced by circadian luciferase reporter genes, we showed that simulated body temperature cycles of mice and even humans, with daily temperature differences of only 3°C and 1°C, respectively, could gradually synchronize circadian gene expression in cultured fibroblasts. The time required for establishing the new steady-state phase depended on the reporter gene, but after a few days, the expression of each gene oscillated with a precise phase relative to that of the temperature cycles. Smooth temperature oscillations with a very small amplitude could synchronize fibroblast clocks over a wide temperature range, and such temperature rhythms were also capable of entraining gene expression cycles to periods significantly longer or shorter than 24 h. As revealed by genetic loss-of-function experiments, heat-shock factor 1 (HSF1), but not HSF2, was required for the efficient synchronization of fibroblast oscillators to simulated body temperature cycles. PMID:22379191

  18. Simulated body temperature rhythms reveal the phase-shifting behavior and plasticity of mammalian circadian oscillators.

    Science.gov (United States)

    Saini, Camille; Morf, Jörg; Stratmann, Markus; Gos, Pascal; Schibler, Ueli

    2012-03-15

    The circadian pacemaker in the suprachiasmatic nuclei (SCN) of the hypothalamus maintains phase coherence in peripheral cells through metabolic, neuronal, and humoral signaling pathways. Here, we investigated the role of daily body temperature fluctuations as possible systemic cues in the resetting of peripheral oscillators. Using precise temperature devices in conjunction with real-time monitoring of the bioluminescence produced by circadian luciferase reporter genes, we showed that simulated body temperature cycles of mice and even humans, with daily temperature differences of only 3°C and 1°C, respectively, could gradually synchronize circadian gene expression in cultured fibroblasts. The time required for establishing the new steady-state phase depended on the reporter gene, but after a few days, the expression of each gene oscillated with a precise phase relative to that of the temperature cycles. Smooth temperature oscillations with a very small amplitude could synchronize fibroblast clocks over a wide temperature range, and such temperature rhythms were also capable of entraining gene expression cycles to periods significantly longer or shorter than 24 h. As revealed by genetic loss-of-function experiments, heat-shock factor 1 (HSF1), but not HSF2, was required for the efficient synchronization of fibroblast oscillators to simulated body temperature cycles.

  19. Identifying Floppy and Rigid Regions in Proteins

    Science.gov (United States)

    Jacobs, D. J.; Thorpe, M. F.; Kuhn, L. A.

    1998-03-01

    In proteins it is possible to separate hard covalent forces involving bond lengths and bond angles from other weak forces. We model the microstructure of the protein as a generic bar-joint truss framework, where the hard covalent forces and strong hydrogen bonds are regarded as rigid bar constraints. We study the mechanical stability of proteins using FIRST (Floppy Inclusions and Rigid Substructure Topography) based on a recently developed combinatorial constraint counting algorithm (the 3D Pebble Game), which is a generalization of the 2D pebble game (D. J. Jacobs and M. F. Thorpe, ``Generic Rigidity: The Pebble Game'', Phys. Rev. Lett.) 75, 4051-4054 (1995) for the special class of bond-bending networks (D. J. Jacobs, "Generic Rigidity in Three Dimensional Bond-bending Networks", Preprint Aug (1997)). This approach is useful in identifying rigid motifs and flexible linkages in proteins, and thereby determines the essential degrees of freedom. We will show some preliminary results from the FIRST analysis on the myohemerythrin and lyozyme proteins.

  20. Sociocultural influences on eating attitudes and behaviors, body image, and psychological functioning: a comparison of African-American, Asian-American, and Caucasian college women.

    Science.gov (United States)

    Akan, G E; Grilo, C M

    1995-09-01

    Eating attitudes and behaviors, body image, and psychological functioning were evaluated in 98 female college students: 36 African-Americans, 34 Asian-Americans, and 28 Caucasians. African-Americans had significantly higher body mass index than either Asian-American or Caucasians. In contrast, Caucasians reported greater levels of disordered eating and dieting behaviors and attitudes and greater body dissatisfaction than did Asian-Americans and African-Americans who differed little on these measures. The nature of variability in these eating behaviors and attitudes and body image was also examined within each of the three groups. A generally consistent pattern emerged within each racial group: low self-esteem and high public self-consciousness were associated with greater levels of problematic eating behaviors and attitudes and body dissatisfaction. A history of being teased about weight and size was associated with problematic eating behaviors and attitudes and body dissatisfaction in African-Americans and Caucasians but not in Asian-Americans. The findings suggest that there exist important racial differences on various aspects of eating, dieting, and body image in college women. Contrary to hypothesis, the degree of acculturation and assimilation within the African-American and Asian-American groups was unrelated to variability in these domains.

  1. Psychological aspects of the cancer patients' education: thoughts, feelings, behavior and body reactions of patients faced with diagnosis of cancer.

    Science.gov (United States)

    Klikovac, T; Djurdjevic, A

    2010-01-01

    In order to assess the impact of cancer diagnosis on several psychological dimensions, this study was undertaken with the aim to understand, identify and document the psychological responses of cancer patients - their common thoughts, feelings, body sensations and behavior when they faced the cancer diagnosis. The sample consisted of 80 patients who attended psychological lectures during the implementation of the European Educational Programme (EEP) "Learning to live with cancer". At the beginning of the lectures, the patients were asked to fulfill the self-describing questionnaire with 4 open questions: "Describe your common thoughts, feelings, behavior, and body reactions in the first 6 weeks when you learned that you were affected by cancer". A significant proportion of patients reported disease denial (65%) and reexamination in relation to past life experiences, stressful events and bad habits (60%). Depressive feelings and disappointment were reported by 90% of the patients, while 85% of them reported fear, hopelessness and emptiness. They also reported sadness (70%), anger and anxiety (65%), nervousness and irritability (90%). Positive thoughts and attitude in the sense of optimism concerning a successful treatment outcome were reported by 20% and 15% of patients, respectively. The diagnosis of cancer and cancer treatment can cause distress, emotional turmoil and different psychosocial disorders. Taking into consideration different psychological reactions of cancer patients can be helpful for organizing adequate psycho-educational and psychosocial support, and psychotherapy for cancer patients and their families.

  2. Durable bistable auxetics made of rigid solids

    Science.gov (United States)

    Shang, Xiao; Liu, Lu; Rafsanjani, Ahmad; Pasini, Damiano

    2018-02-01

    Bistable Auxetic Metamaterials (BAMs) are a class of monolithic perforated periodic structures with negative Poisson's ratio. Under tension, a BAM can expand and reach a second state of equilibrium through a globally large shape transformation that is ensured by the flexibility of its elastomeric base material. However, if made from a rigid polymer, or metal, BAM ceases to function due to the inevitable rupture of its ligaments. The goal of this work is to extend the unique functionality of the original kirigami architecture of BAM to a rigid solid base material. We use experiments and numerical simulations to assess performance, bistability and durability of rigid BAMs at 10,000 cycles. Geometric maps are presented to elucidate the role of the main descriptors of BAM architecture. The proposed design enables the realization of BAM from a large palette of materials, including elastic-perfectly plastic materials and potentially brittle materials.

  3. Body-image and obesity in adolescence: a comparative study of social-demographic, psychological, and behavioral aspects.

    Science.gov (United States)

    de Sousa, Pedro Miguel Lopes

    2008-11-01

    In current society, body and beauty's cult emerge as one of the main factors of adolescence. That leads adolescents to be dissatisfied with their own appearance, to psychological maladjustment, and nutritional disorders. This quantitative, exploratory, and cross-sectional research evaluates how adolescents perceive their weight and the prevalence of obesity in a sample of adolescents from the district of Viseu (Portugal). It also attempted to compare the relation of body-image and obesity with sociodemographic (school, sex, age, socioeconomic status, family functioning), psychological (self-concept, depression, school success) and behavioral aspects (physical inactivity). After data analyses, it was verified that the prevalence of obesity was 8.8% but 12.7% considered themselves obese. These adolescents had higher physical inactivity, poorer family functioning, a lower self-concept, and a higher depression index. The really obese adolescents were older and had poorer academic results. Obesity was higher in boys, but girls perceived themselves more as being obese. In conclusion, it is essential to evaluate weight perception in addition to body mass index (BMI), because the main problem could be related not only to being obese, but also to the perception of having a higher than ideal weight.

  4. Sintering behavior of porous wall tile bodies during fast single-firing process

    Directory of Open Access Journals (Sweden)

    Sidnei José Gomes Sousa

    2005-06-01

    Full Text Available In ceramic wall tile processing, fast single-firing cycles have been widely used. In this investigation a fast single-firing porous wall tile mixture was prepared using raw materials from the North Fluminense region.Specimens were obtained by uniaxial pressing and sintered in air at various temperatures (1080 - 1200 °C using a fast-firing cycle (60 minutes. Evolution of the microstructure was followed by XRD and SEM. The results revealed that the main phases formed during the sintering step are anorthite, gehlenite and hematite. It appears that the sintering process is characterized by the presence of a small amount of a liquid phase below 1140 °C. As a result, the microstructure of the ceramic bodies showed a network of small dense zones interconnected with a porous phase. In addition, the strength of the material below 1140 °C appeared to be related to the type and quantity of crystalline phases in the sintered bodies.

  5. Increased variability of bone tissue mineral density resulting from estrogen deficiency influences creep behavior in a rat vertebral body.

    Science.gov (United States)

    Kim, Do-Gyoon; Navalgund, Anand R; Tee, Boon Ching; Noble, Garrett J; Hart, Richard T; Lee, Hye Ri

    2012-11-01

    Progressive vertebral deformation increases the fracture risk of a vertebral body in the postmenopausal patient. Many studies have observed that bone can demonstrate creep behavior, defined as continued time-dependent deformation even when mechanical loading is held constant. Creep is a characteristic of viscoelastic behavior, which is common in biological materials. We hypothesized that estrogen deficiency-dependent alteration of the mineral distribution of bone at the tissue level could influence the progressive postmenopausal vertebral deformity that is observed as the creep response at the organ level. The objective of this study was thus to examine whether the creep behavior of vertebral bone is changed by estrogen deficiency, and to determine which bone property parameters are responsible for the creep response of vertebral bone at physiological loading levels using an ovariectomized (OVX) rat model. Correlations of creep parameters with bone mineral density (BMD), tissue mineral density (TMD) and architectural parameters of both OVX and sham surgery vertebral bone were tested. As the vertebral creep was not fully recovered during the post-creep unloading period, there was substantial residual displacement for both the sham and OVX groups. A strong positive correlation between loading creep and residual displacement was found (r=0.868, pcreep behavior of the OVX group (pcreep caused progressive, permanent reduction in vertebral height for both the sham and OVX groups. In addition, estrogen deficiency-induced active bone remodeling increased variability of trabecular TMD in the OVX group. Taken together, these results suggest that increased variability of trabecular TMD resulting from high bone turnover influences creep behavior of the OVX vertebrae. Copyright © 2012 Elsevier Inc. All rights reserved.

  6. Effect of rigid inclusions on sintering

    International Nuclear Information System (INIS)

    Rahaman, M.N.; De Jonghe, L.C.

    1988-01-01

    The predictions of recent theoretical studies on the effect of inert, rigid inclusions on the sintering of ceramic powder matrices are examined and compared with experimental data. The densification of glass matrix composites with inclusion volume fractions of ≤0.15 can be adequately explained by Scherer's theory for viscous sintering with rigid inclusions. Inclusions cause a vast reduction in the densification rates of polycrystalline matrix composites even at low inclusion volume fractions. Models put forward to explain the sintering of polycrystalline matrix composites are discussed

  7. Type number and rigidity of fibred surfaces

    International Nuclear Information System (INIS)

    Markov, P E

    2001-01-01

    Infinitesimal l-th order bendings, 1≤l≤∞, of higher-dimensional surfaces are considered in higher-dimensional flat spaces (for l=∞ an infinitesimal bending is assumed to be an analytic bending). In terms of the Allendoerfer type number, criteria are established for the (r,l)-rigidity (in the terminology of Sabitov) of such surfaces. In particular, an (r,l)-infinitesimal analogue is proved of the classical theorem of Allendoerfer on the unbendability of surfaces with type number ≥3 and the class of (r,l)-rigid fibred surfaces is distinguished

  8. Rigid origami vertices: conditions and forcing sets

    Directory of Open Access Journals (Sweden)

    Zachary Abel

    2016-04-01

    Full Text Available We develop an intrinsic necessary and sufficient condition for single-vertex origami crease patterns to be able to fold rigidly.  We classify such patterns in the case where the creases are pre-assigned to be mountains and valleys as well as in the unassigned case.  We also illustrate the utility of this result by applying it to the new concept of minimal forcing sets for rigid origami models, which are the smallest collection of creases that, when folded, will force all the other creases to fold in a prescribed way.

  9. Evaluating a method for automated rigid registration

    DEFF Research Database (Denmark)

    Darkner, Sune; Vester-Christensen, Martin; Larsen, Rasmus

    2007-01-01

    to point distance. T-test for common mean are used to determine the performance of the two methods (supported by a Wilcoxon signed rank test). The performance influence of sampling density, sampling quantity, and norms is analyzed using a similar method.......We evaluate a novel method for fully automated rigid registration of 2D manifolds in 3D space based on distance maps, the Gibbs sampler and Iterated Conditional Modes (ICM). The method is tested against the ICP considered as the gold standard for automated rigid registration. Furthermore...

  10. Studying the effects of dietary body weight-adjusted acute tryptophan depletion on punishment-related behavioral inhibition.

    Science.gov (United States)

    Gaber, Tilman J; Dingerkus, Vita L S; Crockett, Molly J; Bubenzer-Busch, Sarah; Helmbold, Katrin; Sánchez, Cristina L; Dahmen, Brigitte; Herpertz-Dahlmann, Beate; Zepf, Florian D

    2015-01-01

    Alterations in serotonergic (5-HT) neurotransmission are thought to play a decisive role in affective disorders and impulse control. This study aims to reproduce and extend previous findings on the effects of acute tryptophan depletion (ATD) and subsequently diminished central 5-HT synthesis in a reinforced categorization task using a refined body weight-adjusted depletion protocol. Twenty-four young healthy adults (12 females, mean age [SD]=25.3 [2.1] years) were subjected to a double-blind within-subject crossover design. Each subject was administered both an ATD challenge and a balanced amino acid load (BAL) in two separate sessions in randomized order. Punishment-related behavioral inhibition was assessed using a forced choice go/no-go task that incorporated a variable payoff schedule. Administration of ATD resulted in significant reductions in TRP measured in peripheral blood samples, indicating reductions of TRP influx across the blood-brain barrier and related brain 5-HT synthesis. Overall accuracy and response time performance were improved after ATD administration. The ability to adjust behavioral responses to aversive outcome magnitudes and behavioral adjustments following error contingent punishment remained intact after decreased brain 5-HT synthesis. A previously observed dissociation effect of ATD on punishment-induced inhibition was not observed. Our results suggest that neurodietary challenges with ATD Moja-De have no detrimental effects on task performance and punishment-related inhibition in healthy adults.

  11. Acculturation and environmental factors influencing dietary behaviors and body mass index of Chinese students in the United States.

    Science.gov (United States)

    Wu, Beiwen; Smith, Chery

    2016-08-01

    Focus groups (n = 7) were conducted with Chinese students (n = 43) studying in the USA to determine how acculturation and environmental factors influence dietary behavior and body mass index (BMI). This study used mixed methodology, collecting both qualitative (focus groups) and quantitative (24-h dietary recalls, food adoption scores, degree of acculturation, and height and weight measures) data. Themes emerging from focus group discussions were: a) dietary and social acculturation, b) factors influencing food intake, c) cultural importance of food, and d) changes in weight and BMI status. Environmental, behavioral, and cultural factors appear to have impacted the eating behaviors of the students. Because of the nature of the study, self-reported heights and weights were used to calculate BMI while living in China and actual heights and weights were taken for each student at the focus group to calculate current BMI after living in the USA. The majority of Chinese students (69% males; 85% females) experienced weight gain, resulting in an increased BMI based on weight/height data and as reported in focus group discussions. As a result, if students continue to gain weight, they may be at higher risk of developing chronic diseases in the future. Further, implemented dietary change may be transferred to other family members if students return to China. Results suggest that nutrition education should be provided to incoming foreign students during their orientation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Studying the effects of dietary body weight-adjusted acute tryptophan depletion on punishment-related behavioral inhibition

    Directory of Open Access Journals (Sweden)

    Tilman J. Gaber

    2015-08-01

    Full Text Available Background: Alterations in serotonergic (5-HT neurotransmission are thought to play a decisive role in affective disorders and impulse control. Objective: This study aims to reproduce and extend previous findings on the effects of acute tryptophan depletion (ATD and subsequently diminished central 5-HT synthesis in a reinforced categorization task using a refined body weight–adjusted depletion protocol. Design: Twenty-four young healthy adults (12 females, mean age [SD]=25.3 [2.1] years were subjected to a double-blind within-subject crossover design. Each subject was administered both an ATD challenge and a balanced amino acid load (BAL in two separate sessions in randomized order. Punishment-related behavioral inhibition was assessed using a forced choice go/no-go task that incorporated a variable payoff schedule. Results: Administration of ATD resulted in significant reductions in TRP measured in peripheral blood samples, indicating reductions of TRP influx across the blood–brain barrier and related brain 5-HT synthesis. Overall accuracy and response time performance were improved after ATD administration. The ability to adjust behavioral responses to aversive outcome magnitudes and behavioral adjustments following error contingent punishment remained intact after decreased brain 5-HT synthesis. A previously observed dissociation effect of ATD on punishment-induced inhibition was not observed. Conclusions: Our results suggest that neurodietary challenges with ATD Moja–De have no detrimental effects on task performance and punishment-related inhibition in healthy adults.

  13. Modifying Eating Behavior: Novel Approaches for Reducing Body Weight, Preventing Weight Regain, and Reducing Chronic Disease Risk123

    Science.gov (United States)

    Gletsu-Miller, Nana; McCrory, Megan A

    2014-01-01

    This article is a summary of the symposium “Modifying Eating Behavior: Novel Approaches for Reducing Body Weight, Preventing Weight Regain, and Reducing Chronic Disease Risk” held 29 April 2014 at the ASN Scientific Sessions and Annual Meeting at Experimental Biology 2014 in San Diego, CA. In this symposium, novel approaches to modifying eating behavior were highlighted, including 1) alteration of meal timing and macronutrient composition and 2) retraining and provision of feedback about eating behavior. Dr. Ciampolini discussed a method for teaching individuals to recognize a decrease in blood glucose concentration, and therefore the need for energy, by learning the associated physical sensations (signifying hunger). Dr. Madar and Sigal Sofer presented their work on reducing hunger during energy reduction by feeding carbohydrate only in the evening. Dr. Hamilton-Shield reviewed studies on the Mandometer (Mikrodidakt), a device for training individuals to slow eating rate. Finally, Dr. Sazonov presented information on a wearable device, the Automatic Ingestion Monitor, which senses jaw motion and/or hand-to-mouth gestures to detect and characterize food intake. His goal is to use the instrument to prevent overeating by providing feedback to the user to stop ingestion at a predetermined limit. PMID:25398742

  14. How Segregation Makes Us Fat: Food Behaviors and Food Environment as Mediators of the Relationship Between Residential Segregation and Individual Body Mass Index

    OpenAIRE

    Melody Goodman; Sarah Lyons; Lorraine T. Dean; Cassandra Arroyo; James Aaron Hipp

    2018-01-01

    ObjectivesRacial residential segregation affects food landscapes that dictate residents’ food environments and is associated with obesity risk factors, including individual dietary patterns and behaviors. We examine if food behaviors and environments mediate the association between segregation and body mass index (BMI).MethodsNon-Hispanic Whites and Blacks living in the St. Louis and Kansas City metro regions from 2012 to 2013 were surveyed on dietary behaviors, food environment, and BMI (n =...

  15. Incremental impact of body mass status with modifiable unhealthy lifestyle behaviors on pharmaceutical expenditure.

    Science.gov (United States)

    Kim, Tae Hyun; Lee, Eui-Kyung; Han, Euna

    Overweight/obesity is a growing health risk in Korea. The impact of overweight/obesity on pharmaceutical expenditure can be larger if individuals have multiple risk factors and multiple comorbidities. The current study estimated the combined effects of overweight/obesity and other unhealthy behaviors on pharmaceutical expenditure. An instrumental variable quantile regression model was estimated using Korea Health Panel Study data. The current study extracted data from 3 waves (2009, 2010, and 2011). The final sample included 7148 person-year observations for adults aged 20 years or older. Overweight/obese individuals had higher pharmaceutical expenditure than their non-obese counterparts only at the upper quantiles of the conditional distribution of pharmaceutical expenditure (by 119% at the 90th quantile and 115% at the 95th). The current study found a stronger association at the upper quantiles among men (152%, 144%, and 150% at the 75th, 90th, and 95th quantiles, respectively) than among women (152%, 150%, and 148% at the 75th, 90th, and 95th quantiles, respectively). The association at the upper quantiles was stronger when combined with moderate to heavy drinking and no regular physical check-up, particularly among males. The current study confirms that the association of overweight/obesity with modifiable unhealthy behaviors on pharmaceutical expenditure is larger than with overweight/obesity alone. Assessing the effect of overweight/obesity with lifestyle risk factors can help target groups for public health intervention programs. Copyright © 2015 Elsevier Inc. All rights reserved.

  16. Bending behaviors of fully covered biodegradable polydioxanone biliary stent for human body by finite element method.

    Science.gov (United States)

    Liu, Yanhui; Zhu, Guoqing; Yang, Huazhe; Wang, Conger; Zhang, Peihua; Han, Guangting

    2018-01-01

    This paper presents a study of the bending flexibility of fully covered biodegradable polydioxanone biliary stents (FCBPBs) developed for human body. To investigate the relationship between the bending load and structure parameter (monofilament diameter and braid-pin number), biodegradable polydioxanone biliary stents derived from braiding method were covered with membrane prepared via electrospinning method, and nine FCBPBSs were then obtained for bending test to evaluate the bending flexibility. In addition, by the finite element method, nine numerical models based on actual biliary stent were established and the bending load was calculated through the finite element method. Results demonstrate that the simulation and experimental results are in good agreement with each other, indicating that the simulation results can be provided a useful reference to the investigation of biliary stents. Furthermore, the stress distribution on FCBPBSs was studied, and the plastic dissipation analysis and plastic strain of FCBPBSs were obtained via the bending simulation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Primary School Children's Health Behaviors, Attitudes, and Body Mass Index After a 10-Week Lifestyle Intervention With Follow-Up

    Directory of Open Access Journals (Sweden)

    Elise C. Brown

    2018-05-01

    Full Text Available Background: Given the current global child obesity epidemic, testing the effectiveness of interventions in reducing obesity and its influencers is paramount. The purpose of this study was to determine immediate and long-term changes in body mass index and psychosocial variables following a 10-week lifestyle intervention.Methods: Seven hundred and seventy participants (8.75 ± 0.98 years of age, 379 boys and 391 girls took part in the study. Participants had height, weight, and psychosocial questionnaires assessed at pre- and post-control, pre- and post-intervention, and 6-months post-intervention. Participants completed a weekly 10-week intervention consisting of healthy eating and physical activity education, physical activity, parental involvement, and behavior change techniques. Regression models were fit with correlated errors where the correlation occurred only between time points, not between subjects, and the nesting effects of school and area deprivation were controlled.Results: Regression models revealed a significant decrease in body mass index from pre- to post-intervention of 0.8512 kg/m2 (P = 0.0182. No Changes in body mass index occurred from post-intervention to 6-month follow-up (P = 0.5446. The psychosocial variables did not significantly change.Conclusions: This lifestyle intervention may be an effective means for improving body mass index in primary school children in the short-term if the duration of the intervention is increased, but these changes may not be sustained without on-going support.

  18. Motivation and body-related factors as discriminators of change in adolescents' exercise behavior profiles.

    Science.gov (United States)

    Gillison, Fiona B; Standage, Martyn; Skevington, Suzanne M

    2011-01-01

    A prospective study was conducted to explore the relative contributions of weight-related self-perceptions and exercise-related motivation variables in predicting change in leisure-time exercise within a sample of adolescents in the United Kingdom. A cohort of 310 adolescents (51% male, Mean age = 14.08 ± .32 years at baseline) was classified into four groups on the basis of reported change in leisure-time exercise over 10-months: those who maintain, drop out from exercise, take up exercise, and those who were continually inactive. Discriminant function analyses were conducted to predict group membership from adolescents' profiles of motivational and weight-related perceptions at baseline. For boys, the first discriminant function (DF1) revealed that exercise maintainers reported higher identified regulation, introjected regulation, competence, relatedness, and body satisfaction than all other groups (between-group R(2) = .45). DF2 was more indicative of current exercise levels than change, indicating higher intrinsic motivation and lower amotivation for both active groups at baseline (between-group R(2) = .40). In girls, DF1 showed that exercise maintainers reported higher intrinsic motivation, identified regulation, autonomy, competence, relatedness, and lower external regulation than all other groups (between-group R(2) = .58). DF2 indicated that higher body mass index, and perceiving greater pressure to lose weight positively predicted drop out, and negatively predicted exercise uptake (between-group R(2) = .26). Fostering autonomous (self-determined) motivation seems a key determinant to maintaining leisure-time exercise for both boys and girls. Additionally, reducing perceptions of pressure to lose weight and promoting positive interactions with others during exercise may be particularly useful to prevent dropout in girls. Copyright © 2011 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

  19. CNS β3-adrenergic receptor activation regulates feeding behavior, white fat browning, and body weight.

    Science.gov (United States)

    Richard, Jennifer E; López-Ferreras, Lorena; Chanclón, Belén; Eerola, Kim; Micallef, Peter; Skibicka, Karolina P; Wernstedt Asterholm, Ingrid

    2017-09-01

    Pharmacological β 3 -adrenergic receptor (β 3 AR) activation leads to increased mitochondrial biogenesis and activity in white adipose tissue (WAT), a process commonly referred to as "browning", and transiently increased insulin release. These effects are associated with improved metabolic function and weight loss. It is assumed that this impact of β 3 AR agonists is mediated solely through activation of β 3 ARs in adipose tissue. However, β 3 ARs are also found in the brain, in areas such as the brain stem and the hypothalamus, which provide multisynaptic innervation to brown and white adipose depots. Thus, contrary to the current adipocentric view, the central nervous system (CNS) may also have the ability to regulate energy balance and metabolism through actions on central β 3 ARs. Therefore, this study aimed to elucidate whether CNS β 3 ARs can regulate browning of WAT and other aspects of metabolic regulation, such as food intake control and insulin release. We found that acute central injection of β 3 AR agonist potently reduced food intake, body weight, and increased hypothalamic neuronal activity in rats. Acute central β 3 AR stimulation was also accompanied by a transient increase in circulating insulin levels. Moreover, subchronic central β 3 AR agonist treatment led to a browning response in both inguinal (IWAT) and gonadal WAT (GWAT), along with reduced GWAT and increased BAT mass. In high-fat, high-sugar-fed rats, subchronic central β 3 AR stimulation reduced body weight, chow, lard, and sucrose water intake, in addition to increasing browning of IWAT and GWAT. Collectively, our results identify the brain as a new site of action for the anorexic and browning impact of β 3 AR activation. Copyright © 2017 the American Physiological Society.

  20. Combinatorial and Algorithmic Rigidity: Beyond Two Dimensions

    Science.gov (United States)

    2012-12-01

    44]. Theorems of Maxwell- Laman type were ob- tained in [9, 15, 43]. 2 3. Counting and Enumeration. As anticipated in the project, we relied on methods...decompositions. Graphs and Combinatorics, 25:219–238, 2009. [43] I. Streinu and L. Theran. Slider-pinning rigidity: a Maxwell- Laman -type theorem. Discrete and

  1. Birationally rigid varieties. I. Fano varieties

    International Nuclear Information System (INIS)

    Pukhlikov, A V

    2007-01-01

    The theory of birational rigidity of rationally connected varieties generalises the classical rationality problem. This paper gives a survey of the current state of this theory and traces its history from Noether's theorem and the Lueroth problem to the latest results on the birational superrigidity of higher-dimensional Fano varieties. The main components of the method of maximal singularities are considered.

  2. Rigid polyurethane and kenaf core composite foams

    Science.gov (United States)

    Rigid polyurethane foams are valuable in many construction applications. Kenaf is a bast fiber plant where the surface stem skin provides bast fibers whose strength-to-weight ratio competes with glass fiber. The higher volume product of the kenaf core is an under-investigated area in composite appli...

  3. Rigidity Sensing Explained by Active Matter Theory

    OpenAIRE

    Marcq, Philippe; Yoshinaga, Natsuhiko; Prost, Jacques

    2011-01-01

    The magnitude of traction forces exerted by living animal cells on their environment is a monotonically increasing and approximately sigmoidal function of the stiffness of the external medium. We rationalize this observation using active matter theory, and propose that adaptation to substrate rigidity results from an interplay between passive elasticity and active contractility.

  4. About deformation and rigidity in relativity

    International Nuclear Information System (INIS)

    Coll, Bartolome

    2007-01-01

    The notion of deformation involves that of rigidity. In relativity, starting from Born's early definition of rigidity, some other ones have been proposed, offering more or less interesting aspects but also accompanied of undesired or even pathological properties. In order to clarify the origin of these difficulties presented by the notion of rigidity in relativity, we analyze with some detail significant aspects of the unambiguous classical, Newtonian, notion. In particular, the relative character of its kinetic definition is pointed out, allowing to predict and to understand the limitations imposed by Herglotz-Noether theorem. Also, its equivalent dynamic definition is obtained and, in contrast, its absolute character is shown. But in spite of this absolute character, the dynamic definition is shown to be not extensible to relativity. The metric deformation of Minkowski space by the presence of a gravitational field is interpreted as a universal deformation, and it is shown that, under natural conditions, only a simple deformation law is possible, relating locally, but in an one-to-one way, gravitational fields and gauge classes of two-forms. We argue that fields of unit vectors associated to the internal gauge class of two-forms of every space-time (and, in particular, of Minkowski space-time) are the relativistic analogues of the classical accelerated observers, i.e. of the classical rigid motions. Some other consequences of the universal law of gravitational deformation are commented

  5. Rigid pricing and rationally inattentive consumer

    Czech Academy of Sciences Publication Activity Database

    Matějka, Filip

    2010-01-01

    Roč. 20, č. 2 (2010), s. 1-40 ISSN 1211-3298 R&D Projects: GA MŠk LC542 Institutional research plan: CEZ:AV0Z70850503 Keywords : rational inattention * nominal rigidity Subject RIV: AH - Economics http://www.cerge-ei.cz/pdf/wp/Wp409.pdf

  6. Cracking of open traffic rigid pavement

    Directory of Open Access Journals (Sweden)

    Niken Chatarina

    2017-01-01

    Full Text Available The research is done by observing the growth of real structure cracking in Natar, Lampung, Indonesia compared to C. Niken’s et al research and literature study. The rigid pavement was done with open traffic system. There are two main crack types on Natar rigid pavement: cracks cross the road, and cracks spreads on rigid pavement surface. The observation of cracks was analyzed by analyzing material, casting, curing, loading and shrinkage mechanism. The relationship between these analysis and shrinkage mechanism was studied in concrete micro structure. Open traffic make hydration process occur under vibration; therefore, fresh concrete was compressed and tensioned alternately since beginning. High temperature together with compression, cement dissociation, the growth of Ca2+ at very early age leads abnormal swelling. No prevention from outside water movement leads hydration process occur with limited water which caused spreads fine cracks. Limited water improves shrinkage and plastic phase becomes shorter; therefore, rigid pavement can’t accommodate the abnormal swelling and shrinking alternately and creates the spread of cracks. Discontinuing casting the concrete makes both mix under different condition, the first is shrink and the second is swell and creates weak line on the border; so, the cracks appear as cracks across the road.

  7. Overestimation of own body weights in female university students: associations with lifestyles, weight control behaviors and depression.

    Science.gov (United States)

    Kim, Miso; Lee, Hongmie

    2010-12-01

    The study aimed to analyze the lifestyles, weight control behavior, dietary habits, and depression of female university students. The subjects were 532 students from 8 universities located in 4 provinces in Korea. According to percent ideal body weight, 33 (6.4%), 181 (34.0%), 283 (53.2%), 22 (4.1%) and 13 (2.5%) were severely underweight, underweight, normal, overweight and obese, respectively, based on self-reported height and weight. As much as 64.1% and only 2.4%, respectively, overestimated and underestimated their body weight status. Six overweight subjects were excluded from overestimation group for the purpose of this study, resulting in overestimation group consisting of only underweight and normal weight subjects. Compared to those from the normal perception group, significantly more subjects from the overestimation group were currently smoking (P = 0.017) and drank more often than once a week (P = 0.015), without any significant differences in dietary habits. Despite similar BMIs, subjects who overestimated their own weight statuses had significantly higher weight dissatisfaction (P = 0.000), obesity stress (P = 0.000), obsession to lose weight (P = 0.007) and depression (P = 0.018). Also, more of them wanted to lose weight (P = 0.000), checked their body weights more often than once a week (P = 0.025) and had dieting experiences using 'reducing meal size' (P = 0.012), 'reducing snacks' (P = 0.042) and 'taking prescribed pills' (P = 0.032), and presented 'for a wider range of clothes selection' as the reason for weight loss (P = 0.039), although none was actually overweight or obese. Unlike the case with overestimating one's own weight, being overweight was associated with less drinking (P = 0.035) and exercising more often (P = 0.001) and for longer (P = 0.001) and healthier reasons for weight control (P = 0.002), despite no differences in frequency of weighing and depression. The results showed that weight overestimation, independent of weight status

  8. Rigid Spine Syndrome among Children in Oman

    Directory of Open Access Journals (Sweden)

    Roshan Koul

    2015-08-01

    Full Text Available Objectives: Rigidity of the spine is common in adults but is rarely observed in children. The aim of this study was to report on rigid spine syndrome (RSS among children in Oman. Methods: Data on children diagnosed with RSS were collected consecutively at presentation between 1996 and 2014 at the Sultan Qaboos University Hospital (SQUH in Muscat, Oman. A diagnosis of RSS was based on the patient’s history, clinical examination, biochemical investigations, electrophysiological findings, neuro-imaging and muscle biopsy. Atrophy of the paraspinal muscles, particularly the erector spinae, was the diagnostic feature; this was noted using magnetic resonance imaging of the spine. Children with disease onset in the paraspinal muscles were labelled as having primary RSS or rigid spinal muscular dystrophy. Secondary RSS was classified as RSS due to the late involvement of other muscle diseases. Results: Over the 18-year period, 12 children were included in the study, with a maleto- female ratio of 9:3. A total of 10 children were found to have primary RSS or rigid spinal muscular dystrophy syndrome while two had secondary RSS. Onset of the disease ranged from birth to 18 months of age. A family history was noted, with two siblings from one family and three siblings from another (n = 5. On examination, children with primary RSS had typical features of severe spine rigidity at onset, with the rest of the neurological examination being normal. Conclusion: RSS is a rare disease with only 12 reported cases found at SQUH during the study period. Cases of primary RSS should be differentiated from the secondary type.

  9. Survival and behavior of Chinese mystery snails (Bellamya chinensis) in response to simulated water body drawdowns and extended air exposure

    Science.gov (United States)

    Unstad, Kody M.; Uden, Daniel R.; Allen, Craig R.; Chaine, Noelle M.; Haak, Danielle M.; Kill, Robert A.; Pope, Kevin L.; Stephen, Bruce J.; Wong, Alec

    2013-01-01

    Nonnative invasive mollusks degrade aquatic ecosystems and induce economic losses worldwide. Extended air exposure through water body drawdown is one management action used for control. In North America, the Chinese mystery snail (Bellamya chinensis) is an invasive aquatic snail with an expanding range, but eradication methods for this species are not well documented. We assessed the ability of B. chinensis to survive different durations of air exposure, and observed behavioral responses prior to, during, and following desiccation events. Individual B. chinensis specimens survived air exposure in a laboratory setting for > 9 weeks, and survivorship was greater among adults than juveniles. Several B. chinensis specimens responded to desiccation by sealing their opercula and/or burrowing in mud substrate. Our results indicate that drawdowns alone may not be an effective means of eliminating B. chinensis. This study lays the groundwork for future management research that may determine the effectiveness of drawdowns when combined with factors such as extreme temperatures, predation, or molluscicides.

  10. Effects of bark flour of Passiflora edulis on food intake, body weight and behavioral response of rats

    Directory of Open Access Journals (Sweden)

    Dandara A.F. Figueiredo

    Full Text Available ABSTRACT Effects of treatment with the bark flour of Passiflora edulis Sims, Passifloraceae, were evaluated. Adult male Wistar rats were treated for 30 days (130 mg/kg, p.o. with the albedo flour, flavedo and full bark of P. edulis, corresponding to albedo associated with flavedo. Behavioral response observed after treatment with bark flour P. edulis showed sedative effects by the reduction of exploratory activity and increased duration of immobility in the open field test for the group of animals that received the albedo flour associated with the flavedo. Sedative effects were observed in the absence of motor incoordination or muscle relaxation. Food intake of experimental animals was not changed, but the weight gain was decreased both in animals that received only albedo flour, and in those who received the full bark flour. The full bark flour of Passiflora showed sedative effects, without anxiolytic effect detectable and muscle relaxation or motor incoordination, and reduces body weight gain.

  11. LSVT LOUD and LSVT BIG: Behavioral Treatment Programs for Speech and Body Movement in Parkinson Disease

    Directory of Open Access Journals (Sweden)

    Cynthia Fox

    2012-01-01

    Full Text Available Recent advances in neuroscience have suggested that exercise-based behavioral treatments may improve function and possibly slow progression of motor symptoms in individuals with Parkinson disease (PD. The LSVT (Lee Silverman Voice Treatment Programs for individuals with PD have been developed and researched over the past 20 years beginning with a focus on the speech motor system (LSVT LOUD and more recently have been extended to address limb motor systems (LSVT BIG. The unique aspects of the LSVT Programs include the combination of (a an exclusive target on increasing amplitude (loudness in the speech motor system; bigger movements in the limb motor system, (b a focus on sensory recalibration to help patients recognize that movements with increased amplitude are within normal limits, even if they feel “too loud” or “too big,” and (c training self-cueing and attention to action to facilitate long-term maintenance of treatment outcomes. In addition, the intensive mode of delivery is consistent with principles that drive activity-dependent neuroplasticity and motor learning. The purpose of this paper is to provide an integrative discussion of the LSVT Programs including the rationale for their fundamentals, a summary of efficacy data, and a discussion of limitations and future directions for research.

  12. Physical activity, sedentary behavior, and body mass index in the Czech Republic: a nationally representative survey.

    Science.gov (United States)

    Mitáš, Josef; Ding, Ding; Frömel, Karel; Kerr, Jacqueline

    2014-07-01

    Post-communist countries have experienced rapid economic development and social changes, which have been accompanied by changes in health-related lifestyle behaviors, such as physical activity. The purpose of this study was to examine the associations of domain-specific physical activity and total sedentary time with BMI among adults in the Czech Republic. We surveyed a nationally representative sample (n = 4097) of the Czech Republic in fall 2007 using the International Physical Activity Questionnaire (long form). Multiple linear regression analyses were used to examine associations of physical activity, sedentary time and sociodemographic characteristics with BMI. Older age, lower educational attainment, and lower levels of leisure-time physical activity were associated with higher BMI. Compared with those living in large cities, men living in small towns and women living in small villages had higher BMI. This study has identified correlates of BMI in the Czech Republic. Although more evidence from longitudinal studies is needed, findings from the current study can inform interventions to prevent the rising obesity epidemic.

  13. Plasticity of Cerebellar Purkinje Cells in Behavioral Training of Body Balance Control

    Directory of Open Access Journals (Sweden)

    Ray X. Lee

    2015-08-01

    Full Text Available Neural responses to sensory inputs caused by self-generated movements (reafference and external passive stimulation (exafference differ in various brain regions. The ability to differentiate such sensory information can lead to movement execution with better accuracy. However, how sensory responses are adjusted in regard to this distinguishability during motor learning is still poorly understood. The cerebellum has been hypothesized to analyze the functional significance of sensory information during motor learning, and is thought to be a key region of reafference computation in the vestibular system. In this study, we investigated Purkinje cell (PC spike trains as cerebellar cortical output when rats learned to balance on a suspended dowel. Rats progressively reduced the amplitude of body swing and made fewer foot slips during a 5-min balancing task. Both PC simple (SSs; 17 of 26 and complex spikes (CSs; 7 of 12 were found to code initially on the angle of the heads with respect to a fixed reference. Using periods with comparable degrees of movement, we found that such SS coding of information in most PCs (10 of 17 decreased rapidly during balance learning. In response to unexpected perturbations and under anesthesia, SS coding capability of these PCs recovered. By plotting SS and CS firing frequencies over 15-s time windows in double-logarithmic plots, a negative correlation between SS and CS was found in awake, but not anesthetized, rats. PCs with prominent SS coding attenuation during motor learning showed weaker SS-CS correlation. Hence, we demonstrate that neural plasticity for filtering out sensory reafference from active motion occurs in the cerebellar cortex in rats during balance learning. SS-CS interaction may contribute to this rapid plasticity as a form of receptive field plasticity in the cerebellar cortex between two receptive maps of sensory inputs from the external world and of efference copies from the will center for

  14. Imidacloprid-induced impairment of mushroom bodies and behavior of the native stingless bee Melipona quadrifasciata anthidioides.

    Science.gov (United States)

    Tomé, Hudson Vaner V; Martins, Gustavo F; Lima, Maria Augusta P; Campos, Lúcio Antonio O; Guedes, Raul Narciso C

    2012-01-01

    Declines in pollinator colonies represent a worldwide concern. The widespread use of agricultural pesticides is recognized as a potential cause of these declines. Previous studies have examined the effects of neonicotinoid insecticides such as imidacloprid on pollinator colonies, but these investigations have mainly focused on adult honey bees. Native stingless bees (Hymenoptera: Apidae: Meliponinae) are key pollinators in neotropical areas and are threatened with extinction due to deforestation and pesticide use. Few studies have directly investigated the effects of pesticides on these pollinators. Furthermore, the existing impact studies did not address the issue of larval ingestion of contaminated pollen and nectar, which could potentially have dire consequences for the colony. Here, we assessed the effects of imidacloprid ingestion by stingless bee larvae on their survival, development, neuromorphology and adult walking behavior. Increasing doses of imidacloprid were added to the diet provided to individual worker larvae of the stingless bee Melipona quadrifasciata anthidioides throughout their development. Survival rates above 50% were only observed at insecticide doses lower than 0.0056 µg active ingredient (a.i.)/bee. No sublethal effect on body mass or developmental time was observed in the surviving insects, but the pesticide treatment negatively affected the development of mushroom bodies in the brain and impaired the walking behavior of newly emerged adult workers. Therefore, stingless bee larvae are particularly susceptible to imidacloprid, as it caused both high mortality and sublethal effects that impaired brain development and compromised mobility at the young adult stage. These findings demonstrate the lethal effects of imidacloprid on native stingless bees and provide evidence of novel serious sublethal effects that may compromise colony survival. The ecological and economic importance of neotropical stingless bees as pollinators, their

  15. Imidacloprid-induced impairment of mushroom bodies and behavior of the native stingless bee Melipona quadrifasciata anthidioides.

    Directory of Open Access Journals (Sweden)

    Hudson Vaner V Tomé

    Full Text Available Declines in pollinator colonies represent a worldwide concern. The widespread use of agricultural pesticides is recognized as a potential cause of these declines. Previous studies have examined the effects of neonicotinoid insecticides such as imidacloprid on pollinator colonies, but these investigations have mainly focused on adult honey bees. Native stingless bees (Hymenoptera: Apidae: Meliponinae are key pollinators in neotropical areas and are threatened with extinction due to deforestation and pesticide use. Few studies have directly investigated the effects of pesticides on these pollinators. Furthermore, the existing impact studies did not address the issue of larval ingestion of contaminated pollen and nectar, which could potentially have dire consequences for the colony. Here, we assessed the effects of imidacloprid ingestion by stingless bee larvae on their survival, development, neuromorphology and adult walking behavior. Increasing doses of imidacloprid were added to the diet provided to individual worker larvae of the stingless bee Melipona quadrifasciata anthidioides throughout their development. Survival rates above 50% were only observed at insecticide doses lower than 0.0056 µg active ingredient (a.i./bee. No sublethal effect on body mass or developmental time was observed in the surviving insects, but the pesticide treatment negatively affected the development of mushroom bodies in the brain and impaired the walking behavior of newly emerged adult workers. Therefore, stingless bee larvae are particularly susceptible to imidacloprid, as it caused both high mortality and sublethal effects that impaired brain development and compromised mobility at the young adult stage. These findings demonstrate the lethal effects of imidacloprid on native stingless bees and provide evidence of novel serious sublethal effects that may compromise colony survival. The ecological and economic importance of neotropical stingless bees as pollinators

  16. Imidacloprid-Induced Impairment of Mushroom Bodies and Behavior of the Native Stingless Bee Melipona quadrifasciata anthidioides

    Science.gov (United States)

    Tomé, Hudson Vaner V.; Martins, Gustavo F.; Lima, Maria Augusta P.; Campos, Lúcio Antonio O.; Guedes, Raul Narciso C.

    2012-01-01

    Declines in pollinator colonies represent a worldwide concern. The widespread use of agricultural pesticides is recognized as a potential cause of these declines. Previous studies have examined the effects of neonicotinoid insecticides such as imidacloprid on pollinator colonies, but these investigations have mainly focused on adult honey bees. Native stingless bees (Hymenoptera: Apidae: Meliponinae) are key pollinators in neotropical areas and are threatened with extinction due to deforestation and pesticide use. Few studies have directly investigated the effects of pesticides on these pollinators. Furthermore, the existing impact studies did not address the issue of larval ingestion of contaminated pollen and nectar, which could potentially have dire consequences for the colony. Here, we assessed the effects of imidacloprid ingestion by stingless bee larvae on their survival, development, neuromorphology and adult walking behavior. Increasing doses of imidacloprid were added to the diet provided to individual worker larvae of the stingless bee Melipona quadrifasciata anthidioides throughout their development. Survival rates above 50% were only observed at insecticide doses lower than 0.0056 µg active ingredient (a.i.)/bee. No sublethal effect on body mass or developmental time was observed in the surviving insects, but the pesticide treatment negatively affected the development of mushroom bodies in the brain and impaired the walking behavior of newly emerged adult workers. Therefore, stingless bee larvae are particularly susceptible to imidacloprid, as it caused both high mortality and sublethal effects that impaired brain development and compromised mobility at the young adult stage. These findings demonstrate the lethal effects of imidacloprid on native stingless bees and provide evidence of novel serious sublethal effects that may compromise colony survival. The ecological and economic importance of neotropical stingless bees as pollinators, their

  17. Simulating bi-directional pedestrian flow in a cellular automaton model considering the body-turning behavior

    Science.gov (United States)

    Jin, Cheng-Jie; Jiang, Rui; Yin, Jun-Lin; Dong, Li-Yun; Li, Dawei

    2017-09-01

    In the experiments of bi-directional pedestrian flow, it is often observed that pedestrians turn their bodies and change from walking straight to walking sideways, in order to mitigate or avoid the conflicts with opposite walking ones. When these conflicts disappear, pedestrians restore and walk straight again. In the turning states, the forward velocities of pedestrians are not affected. In order to simulate this body-turning behavior, we use a cellular automaton (CA) model named ITP model, which has been proposed before. But the occupied area of one pedestrian is set as 0.4 m∗0.2 m. After the introduction of new rules of turnings and restorations, the pedestrians become more intelligent and flexible during the lane formation process, and some improvements of the fundamental diagram of pedestrian flow can be found. The simulation results of two different scenarios under open boundary conditions are also presented, and compared with the experimental data. It is shown that the new model performs much better than the original model in various tests, which further confirms the validity of the new rules. We think this approach is one useful contribution to the pedestrian flow modeling.

  18. Body language: The interplay between positional behavior and gestural signaling in the genus Pan and its implications for language evolution.

    Science.gov (United States)

    Smith, Lindsey W; Delgado, Roberto A

    2015-08-01

    The gestural repertoires of bonobos and chimpanzees are well documented, but the relationship between gestural signaling and positional behavior (i.e., body postures and locomotion) has yet to be explored. Given that one theory for language evolution attributes the emergence of increased gestural communication to habitual bipedality, this relationship is important to investigate. In this study, we examined the interplay between gestures, body postures, and locomotion in four captive groups of bonobos and chimpanzees using ad libitum and focal video data. We recorded 43 distinct manual (involving upper limbs and/or hands) and bodily (involving postures, locomotion, head, lower limbs, or feet) gestures. In both species, actors used manual and bodily gestures significantly more when recipients were attentive to them, suggesting these movements are intentionally communicative. Adults of both species spent less than 1.0% of their observation time in bipedal postures or locomotion, yet 14.0% of all bonobo gestures and 14.7% of all chimpanzee gestures were produced when subjects were engaged in bipedal postures or locomotion. Among both bonobo groups and one chimpanzee group, these were mainly manual gestures produced by infants and juvenile females. Among the other chimpanzee group, however, these were mainly bodily gestures produced by adult males in which bipedal posture and locomotion were incorporated into communicative displays. Overall, our findings reveal that bipedality did not prompt an increase in manual gesturing in these study groups. Rather, body postures and locomotion are intimately tied to many gestures and certain modes of locomotion can be used as gestures themselves. © 2015 Wiley Periodicals, Inc.

  19. The impact of bodyweight and body condition on behavioral testing for painful diabetic neuropathy in the streptozotocin rat model.

    Science.gov (United States)

    Hoybergs, Yves M J J; Biermans, Ria L V; Meert, Theo F

    2008-05-02

    The streptozotocin (STZ)-induced diabetes model is widely used for the induction of neuropathy in the rat. In this model, diabetic animals often display chronic illness, which raises objections not only on ethical but also on scientific grounds. In this study, the investigators set out to determine the impact of bodyweight and body condition (BC) on behavioral testing in the rat. Animals were allocated to four different groups as a function of their bodyweight, in particular one control group and three experimental groups with different starting weights (low bodyweight [LBW], medium bodyweight [MBW] and high bodyweight [HBW]), the groups having been rendered diabetic with an intraperitoneal injection of STZ (65mg/kg). Bodyweight, blood glucose, body condition and thresholds for mechanical hyperalgesia and tactile allodynia were measured or evaluated over a 68-day period. Animals with a LBW at the start of the experiment showed a gradual increase in BW with a decrease in mechanical nociceptive thresholds, while MBW and HBW animals presented a decrease in both thresholds and BW. The body condition score (BCS) decreased in all STZ-treated groups over time. Since correlations between mechanical thresholds and BW were similar between the control group and the HBW and MBW groups, the loss in BW clearly contributed to the decrease in thresholds. In the LBW group, thresholds and BW correlated negatively, so that the decrease in thresholds was mainly caused by the development of a painful neuropathy. From an ethical and a scientific point of view, in the STZ-induced diabetic neuropathy model, animals should be chosen on the basis of bodyweight and it must also be ensured that STZ is correctly dosed.

  20. From Wage Rigidities to Labour Market Rigidities: A Turning-Point in Explaining Equilibrium Unemployment?

    OpenAIRE

    Marco Guerrazzi; Nicola Meccheri

    2009-01-01

    This paper offers a critical discussion of the concept of labour market rigidity relevant to explaining unemployment. Starting from Keynes’s own view, we discuss how the concept of labour market flexibility has changed over time, involving nominal or real wage flexibility, contract flexibility or labour market institution flexibility. We also provide a critical assessment of the factors that lead the search framework highlighting labour market rigidities (frictions) to challenge the more wide...

  1. Non-rigid registration of tomographic images with Fourier transforms

    International Nuclear Information System (INIS)

    Osorio, Ar; Isoardi, Ra; Mato, G

    2007-01-01

    Spatial image registration of deformable body parts such as thorax and abdomen has important medical applications, but at the same time, it represents an important computational challenge. In this work we propose an automatic algorithm to perform non-rigid registration of tomographic images using a non-rigid model based on Fourier transforms. As a measure of similarity, we use the correlation coefficient, finding that the optimal order of the transformation is n = 3 (36 parameters). We apply this method to a digital phantom and to 7 pairs of patient images corresponding to clinical CT scans. The preliminary results indicate a fairly good agreement according to medical experts, with an average registration error of 2 mm for the case of clinical images. For 2D images (dimensions 512x512), the average running time for the algorithm is 15 seconds using a standard personal computer. Summarizing, we find that intra-modality registration of the abdomen can be achieved with acceptable accuracy for slight deformations and can be extended to 3D with a reasonable execution time

  2. Finite-difference analysis of shells impacting rigid barriers

    International Nuclear Information System (INIS)

    Pirotin, S.D.; Witmer, E.A.

    1977-01-01

    Nuclear power plants must be protected from the adverse effects of missile impacts. A significant category of missile impact involves deformable structures (pressure vessel components, whipping pipes) striking relatively rigid targets (concrete walls, bumpers) which act as protective devices. The response and interaction of these structures is needed to assess the adequacy of these barriers for protecting vital safety related equipment. The present investigation represents an initial attempt to develop an efficient numerical procedure for predicting the deformations and impact force time-histories of shells which impact upon a rigid target. The general large-deflection equations of motion of the shell are expressed in finite-difference form in space and integrated in time through application of the central-difference temporal operator. The effect of material nonlinearities is treated by a mechanical sublayer material model which handles the strain-hardening, Bauschinger, and strain-rate effects. The general adequacy of this shell treatment has been validated by comparing predictions with the results of various experiments in which structures have been subjected to well-defined transient forcing functions (typically high-explosive impulse loading). The 'new' ingredient addressed in the present study involves an accounting for impact interaction and response of both the target structure and the attacking body. (Auth.)

  3. Bimanual coupling paradigm as an effective tool to investigate productive behaviors in motor and body awareness impairments.

    Science.gov (United States)

    Garbarini, Francesca; Pia, Lorenzo

    2013-11-05

    When humans move simultaneously both hands strong coupling effects arise and neither of the two hands is able to perform independent actions. It has been suggested that such motor constraints are tightly linked to action representation rather than to movement execution. Hence, bimanual tasks can represent an ideal experimental tool to investigate internal motor representations in those neurological conditions in which the movement of one hand is impaired. Indeed, any effect on the "moving" (healthy) hand would be caused by the constraints imposed by the ongoing motor program of the 'impaired' hand. Here, we review recent studies that successfully utilized the above-mentioned paradigms to investigate some types of productive motor behaviors in stroke patients. Specifically, bimanual tasks have been employed in left hemiplegic patients who report illusory movements of their contralesional limbs (anosognosia for hemiplegia). They have also been administered to patients affected by a specific monothematic delusion of body ownership, namely the belief that another person's arm and his/her voluntary action belong to them. In summary, the reviewed studies show that bimanual tasks are a simple and valuable experimental method apt to reveal information about the motor programs of a paralyzed limb. Therefore, it can be used to objectively examine the cognitive processes underpinning motor programming in patients with different delusions of motor behavior. Additionally, it also sheds light on the mechanisms subserving bimanual coordination in the intact brain suggesting that action representation might be sufficient to produce these effects.

  4. Bimanual coupling paradigm as an effective tool to investigate productive behaviors in motor and body awareness impairments

    Directory of Open Access Journals (Sweden)

    Francesca eGarbarini

    2013-11-01

    Full Text Available When humans move simultaneously both hands strong coupling effects arise and neither of the two hands is able to perform independent actions. It has been suggested that such motor constraints are tightly linked to action representation rather than to movement execution. Hence, bimanual tasks can represent an ideal experimental tool to investigate internal motor representations in those neurological conditions in which the movement of one hand is impaired. Indeed, any effect on the ‘moving’ (healthy hand would be caused by the constraints imposed by the ongoing motor program of the ‘impaired’ hand. Here, we review recent studies that successfully utilized the above-mentioned paradigms to investigate some types of productive motor behaviors in stroke patients. Specifically, bimanual tasks have been employed in left hemiplegic patients who report illusory movements of their contralesional limbs (anosognosia for hemiplegia. They have also been administered to patients affected by a specific monothematic delusion of body ownership, namely the belief that another person’s arm and his/her voluntary action belong to them. In summary, the reviewed studies show that bimanual tasks are a simple and valuable experimental method apt to reveal information about the motor programs of a paralyzed limb. Therefore, it can be used to objectively examine the cognitive processes underpinning motor programming in patients with different delusions of motor behavior. Additionally, it also sheds light on the mechanisms subserving bimanual coordination in the intact brain suggesting that action representation might be sufficient to produce these effects.

  5. Price Rigidity and Industrial Concentration: Evidence from the Indonesian Food and Beverages Industry

    NARCIS (Netherlands)

    Setiawan, M.; Emvalomatis, G.; Oude Lansink, A.G.J.M.

    2015-01-01

    This paper investigates the relationship between industrial concentration and price rigidity in the Indonesian food and beverages industry. A Cournot model of firm behavior is used in which prices adjust according to a partial adjustment mechanism. The model is applied to panel data of the

  6. Evolution of flexibility and rigidity in retaliatory punishment.

    Science.gov (United States)

    Morris, Adam; MacGlashan, James; Littman, Michael L; Cushman, Fiery

    2017-09-26

    Natural selection designs some social behaviors to depend on flexible learning processes, whereas others are relatively rigid or reflexive. What determines the balance between these two approaches? We offer a detailed case study in the context of a two-player game with antisocial behavior and retaliatory punishment. We show that each player in this game-a "thief" and a "victim"-must balance two competing strategic interests. Flexibility is valuable because it allows adaptive differentiation in the face of diverse opponents. However, it is also risky because, in competitive games, it can produce systematically suboptimal behaviors. Using a combination of evolutionary analysis, reinforcement learning simulations, and behavioral experimentation, we show that the resolution to this tension-and the adaptation of social behavior in this game-hinges on the game's learning dynamics. Our findings clarify punishment's adaptive basis, offer a case study of the evolution of social preferences, and highlight an important connection between natural selection and learning in the resolution of social conflicts.

  7. [Study on the relations among the screen-based sedentary behaviors, family factors and body mass index of children].

    Science.gov (United States)

    Wei, Dong-mei; Wu, Li-jing; Gao, Ai-yu; Li, Qin; Cheng, Lan; Wang, Hai-jun

    2015-06-18

    To explore the relations among screen-based sedentary behaviors (SSB), family factors and body mass index (BMI) of children, and to study how family factors have effect on BMI through influencing SSB. A total of 1,846 students aged 7-11 years from 12 primary schools in one district of Beijing were included. Their body weight and height were measured to calculate the BMI. The time of SSB and family factors were investigated by using questionnaires. The time of SSB was the total time of watching TV and videos, playing computer games and iPad each day during the past 7 days recalled by children. The family factors included the parents' education, occupation, the parents'time of SSB, whether the parents told their child the harm of SSB, the parents'time limit for the children's SSB. The parents'education and occupation were used for calculating the family socioeconomic score. The median time of SSB for children was 1 hour/day, and the interquartile range was 1 hour/day. The BMI of the children with the parents' time limit for the children's SSB less than 120 min/day were smaller than the children with the parents'time limit not less than 120 min/day, in both the boys (1.63 kg/m2, Peffects of SSB time for children on the association between the parents'time limit for the children's SSB and BMI were -0.222 kg/m2 (95%CI:-0.432, -0.095) for boys and -0.187 kg/m2 (95%CI: -0.507, -0.049) for girls, which accounted for 13.67% of the total effects for boys and 22.11% for girls. The parents' time limit for the children's SSB has effect on their BMI through influencing their SSB time. Parents' supervision on the behaviors of children produces larger benefit for BMI than health education conveyed by parents. Therefore, parents' participation in supervising the behaviors of children are indispensable for preventing and controlling childhood obesity.

  8. Financial Constraints and Nominal Price Rigidities

    DEFF Research Database (Denmark)

    Menno, Dominik Francesco; Balleer, Almut; Hristov, Nikolay

    This paper investigates how financial market imperfections and the frequency of price adjustment interact. Based on new firm-level evidence for Germany, we document that financially constrained firms adjust prices more often than their unconstrained counterparts, both upwards and downwards. We show...... that these empirical patterns are consistent with a partial equilibrium menu-cost model with a working capital constraint. We then use the model to show how the presence of financial frictions changes profits and the price distribution of firms compared to a model without financial frictions. Our results suggest...... that tighter financial constraints are associated with higher nominal rigidities, higher prices and lower output. Moreover, in response to aggregate shocks, aggregate price rigidity moves substantially, the response of inflation is dampened, while output reacts more in the presence of financial frictions...

  9. Rigid cohomology over Laurent series fields

    CERN Document Server

    Lazda, Christopher

    2016-01-01

    In this monograph, the authors develop a new theory of p-adic cohomology for varieties over Laurent series fields in positive characteristic, based on Berthelot's theory of rigid cohomology. Many major fundamental properties of these cohomology groups are proven, such as finite dimensionality and cohomological descent, as well as interpretations in terms of Monsky-Washnitzer cohomology and Le Stum's overconvergent site. Applications of this new theory to arithmetic questions, such as l-independence and the weight monodromy conjecture, are also discussed. The construction of these cohomology groups, analogous to the Galois representations associated to varieties over local fields in mixed characteristic, fills a major gap in the study of arithmetic cohomology theories over function fields. By extending the scope of existing methods, the results presented here also serve as a first step towards a more general theory of p-adic cohomology over non-perfect ground fields. Rigid Cohomology over Laurent Series Fields...

  10. Foreign Body Retrieval

    Medline Plus

    Full Text Available ... provides real-time imaging, making it a good tool for guiding removal procedures. In some cases, it is potentially more harmful to remove the ... provides real-time imaging, making it a good tool for guiding foreign body removal ... rare cases, the general anesthesia used during rigid esophagoscopy can ...

  11. Modeling the Flexural Rigidity of Rod Photoreceptors

    Science.gov (United States)

    Haeri, Mohammad; Knox, Barry E.; Ahmadi, Aphrodite

    2013-01-01

    In vertebrate eyes, the rod photoreceptor has a modified cilium with an extended cylindrical structure specialized for phototransduction called the outer segment (OS). The OS has numerous stacked membrane disks and can bend or break when subjected to mechanical forces. The OS exhibits axial structural variation, with extended bands composed of a few hundred membrane disks whose thickness is diurnally modulated. Using high-resolution confocal microscopy, we have observed OS flexing and disruption in live transgenic Xenopus rods. Based on the experimental observations, we introduce a coarse-grained model of OS mechanical rigidity using elasticity theory, representing the axial OS banding explicitly via a spring-bead model. We calculate a bending stiffness of ∼105 nN⋅μm2, which is seven orders-of-magnitude larger than that of typical cilia and flagella. This bending stiffness has a quadratic relation to OS radius, so that thinner OS have lower fragility. Furthermore, we find that increasing the spatial frequency of axial OS banding decreases OS rigidity, reducing its fragility. Moreover, the model predicts a tendency for OS to break in bands with higher spring number density, analogous to the experimental observation that transgenic rods tended to break preferentially in bands of high fluorescence. We discuss how pathological alterations of disk membrane properties by mutant proteins may lead to increased OS rigidity and thus increased breakage, ultimately contributing to retinal degeneration. PMID:23442852

  12. Blast wave interaction with a rigid surface

    International Nuclear Information System (INIS)

    Josey, T.; Whitehouse, D.R.; Ripley, R.C.; Dionne, J.P.

    2004-01-01

    A simple model used to investigate blast wave interactions with a rigid surface is presented. The model uses a constant volume energy source analogue to predict pressure histories at gauges located directly above the charge. A series of two-dimensional axi-symmetric CFD calculations were performed, varying the height of the charge relative to the ground. Pressure histories, along with isopycnic plots are presented to evaluate the effects of placing a charge in close proximity to a rigid surface. When a charge is placed near a solid surface the pressure histories experienced at gauges above the charge indicate the presence of two distinct pressure peaks. The first peak is caused by the primary shock and the second peak is a result of the wave reflections from the rigid surface. As the distance from the charge to the wall is increased the magnitude of the second pressure peak is reduced, provided that the distance between the charge and the gauge is maintained constant. The simple model presented is able to capture significant, predictable flow features. (author)

  13. Lateral rigidity of cracked concrete structures

    International Nuclear Information System (INIS)

    Castellani, A.; Chesi, C.

    1979-01-01

    Numerical results are discussed on the lateral rigidity of reinforced concrete structures with a given crack distribution. They have been favourably checked with experimental results for cylindrical shells under the effect of a thermal gradient producing vertical cracking or vertical plus horizontal cracking. The main effects characterizing the concrete behaviour are: (1) The shear transfer across a crack; (2) The shear transfer degradation after cyclic loading; (3) The tension stiffening provided by the concrete between crack and crack, in the normal stress transfer; (4) The temperature effect on the elastic moduli of concrete, when cracks are of thermal origin. Only the 1st effect is discussed on an experimental basis. Two broad cathegories of reinforced concrete structures have been investigated in this respect: shear walls of buildings and cylindrical containment structures. The main conclusions so far reached are: (1) Vertical cracks are unlikely to decrease the lateral rigidity to less than 80% of the original one, and to less than 90% when they do not involve the entire thickness of the wall; (2) The appearence of horizontal cracks can reduce the lateral rigidity by some 30% or more; (3) A noticeable but not yet evaluated influence is shown by cyclic loading. (orig.)

  14. Stresses in Circular Plates with Rigid Elements

    Science.gov (United States)

    Velikanov, N. L.; Koryagin, S. I.; Sharkov, O. V.

    2018-05-01

    Calculations of residual stress fields are carried out by numerical and static methods, using the flat cross-section hypothesis. The failure of metal when exposed to residual stresses is, in most cases, brittle. The presence in the engineering structures of rigid elements often leads to the crack initiation and structure failure. This is due to the fact that rigid elements under the influence of external stresses are stress concentrators. In addition, if these elements are fixed by welding, the residual welding stresses can lead to an increase in stress concentration and, ultimately, to failure. The development of design schemes for such structures is a very urgent task for complex technical systems. To determine the stresses in a circular plate with a welded circular rigid insert under the influence of an external load, one can use the solution of the plane stress problem for annular plates in polar coordinates. The polar coordinates of the points are the polar radius and the polar angle, and the stress state is determined by normal radial stresses, tangential and shearing stresses. The use of the above mentioned design schemes, formulas, will allow more accurate determination of residual stresses in annular welded structures. This will help to establish the most likely directions of failure and take measures at the stages of designing, manufacturing and repairing engineering structures to prevent these failures. However, it must be taken into account that the external load, the presence of insulation can lead to a change in the residual stress field.

  15. One- or Two-Legged Standing: What Is the More Suitable Protocol to Assess the Postural Effects of the Rigid Ankle Orthosis?

    Science.gov (United States)

    Rougier, Patrice; Genthon, Nicolas; Gallois-Montbrun, Thibault; Brugiere, Steve; Bouvat, Eric

    2009-01-01

    To highlight the capacity of one- and two-legged standing protocols when assessing postural behavior induced by a rigid ankle orthosis, 14 healthy individuals stood upright barefoot and wore either an elastic stocking on the preferred leg or a rigid orthosis with or without additional taping in one- or two-legged (TL) conditions. Traditional…

  16. A virtual pebble game to ensemble average graph rigidity.

    Science.gov (United States)

    González, Luis C; Wang, Hui; Livesay, Dennis R; Jacobs, Donald J

    2015-01-01

    The body-bar Pebble Game (PG) algorithm is commonly used to calculate network rigidity properties in proteins and polymeric materials. To account for fluctuating interactions such as hydrogen bonds, an ensemble of constraint topologies are sampled, and average network properties are obtained by averaging PG characterizations. At a simpler level of sophistication, Maxwell constraint counting (MCC) provides a rigorous lower bound for the number of internal degrees of freedom (DOF) within a body-bar network, and it is commonly employed to test if a molecular structure is globally under-constrained or over-constrained. MCC is a mean field approximation (MFA) that ignores spatial fluctuations of distance constraints by replacing the actual molecular structure by an effective medium that has distance constraints globally distributed with perfect uniform density. The Virtual Pebble Game (VPG) algorithm is a MFA that retains spatial inhomogeneity in the density of constraints on all length scales. Network fluctuations due to distance constraints that may be present or absent based on binary random dynamic variables are suppressed by replacing all possible constraint topology realizations with the probabilities that distance constraints are present. The VPG algorithm is isomorphic to the PG algorithm, where integers for counting "pebbles" placed on vertices or edges in the PG map to real numbers representing the probability to find a pebble. In the VPG, edges are assigned pebble capacities, and pebble movements become a continuous flow of probability within the network. Comparisons between the VPG and average PG results over a test set of proteins and disordered lattices demonstrate the VPG quantitatively estimates the ensemble average PG results well. The VPG performs about 20% faster than one PG, and it provides a pragmatic alternative to averaging PG rigidity characteristics over an ensemble of constraint topologies. The utility of the VPG falls in between the most

  17. 49 CFR 587.18 - Dimensions of fixed rigid barrier.

    Science.gov (United States)

    2010-10-01

    ... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) DEFORMABLE BARRIERS Offset Deformable Barrier § 587.18 Dimensions of fixed rigid barrier. (a) The fixed rigid barrier has a mass of not... 49 Transportation 7 2010-10-01 2010-10-01 false Dimensions of fixed rigid barrier. 587.18 Section...

  18. Animal-Borne Imaging Reveals Novel Insights into the Foraging Behaviors and Diel Activity of a Large-Bodied Apex Predator, the American Alligator (Alligator mississippiensis)

    OpenAIRE

    Nifong, James C.; Nifong, Rachel L.; Silliman, Brian R.; Lowers, Russell H.; Guillette, Louis J.; Ferguson, Jake M.; Welsh, Matthew; Abernathy, Kyler; Marshall, Greg

    2014-01-01

    Large-bodied, top- and apex predators (e.g., crocodilians, sharks, wolves, killer whales) can exert strong top-down effects within ecological communities through their interactions with prey. Due to inherent difficulties while studying the behavior of these often dangerous predatory species, relatively little is known regarding their feeding behaviors and activity patterns, information that is essential to understanding their role in regulating food web dynamics and ecological processes. Here...

  19. Association between parenting practices and children's dietary intake, activity behavior and development of body mass index: the KOALA Birth Cohort Study

    OpenAIRE

    Gubbels, Jessica S; Kremers, Stef PJ; Stafleu, Annette; de Vries, Sanne I; Goldbohm, R Alexandra; Dagnelie, Pieter C; de Vries, Nanne K; van Buuren, Stef; Thijs, Carel

    2011-01-01

    Abstract Background Insights into the effects of energy balance-related parenting practices on children's diet and activity behavior at an early age is warranted to determine which practices should be recommended and to whom. The purpose of this study was to examine child and parent background correlates of energy balance-related parenting practices at age 5, as well as the associations of these practices with children's diet, activity behavior, and body mass index (BMI) development. Methods ...

  20. Can deformation of a polymer film with a rigid coating model geophysical processes?

    Science.gov (United States)

    Volynskii, A. L.; Bazhenov, S. L.

    2007-12-01

    The structural and mechanical behavior of polymer films with a thin rigid coating is analyzed. The behavior of such systems under applied stress is accompanied by the formation of a regular wavy surface relief and by regular fragmentation of the coating. The above phenomena are shown to be universal. Both phenomena (stress-induced development of a regular wavy surface relief and regular fragmentation of the coating) are provided by the specific features of mechanical stress transfer from a compliant soft support to a rigid thin coating. The above phenomena are associated with a specific structure of the system, which is referred to as “a rigid coating on a soft substratum” system (RCSS). Surface microrelief in RCSS systems is similar to the ocean floor relief in the vicinity of mid-oceanic ridges. Thus, the complex system composed of a young oceanic crust and upper Earth's mantle may be considered as typically “a solid coating on a soft substratum” system. Specific features of the ocean floor relief are analyzed in terms of the approach advanced for the description of the structural mechanical behavior of polymer films with a rigid coating. This analysis allowed to estimate the strength of an ocean floor.

  1. Behavioral Own-Body-Transformations in Children and Adolescents With Typical Development, Autism Spectrum Disorder, and Developmental Coordination Disorder

    Directory of Open Access Journals (Sweden)

    Soizic Gauthier

    2018-05-01

    Full Text Available Background: In motor imitation, taking a partner's perspective often involves a mental body transformation from an embodied, ego-centered viewpoint to a disembodied, hetero-centered viewpoint. Impairments of both own-body-transformation (OBT and abnormalities in visual-spatial processing have been reported in patients with neurodevelopmental disorders including autism spectrum disorder (ASD. In the context of a visual-motor interactive task, studying OBT impairments while disentangling the contribution of visual-spatial impairments associated with motor coordination problems has not been investigated.Methods: 85 children and adolescents (39 controls with typical development, TD; 29 patients with ASD; 17 patients with developmental coordination disorder, DCD, aged 6–19 years, participated in a behavioral paradigm in which participants interacted with a virtual tightrope walker (TW standing and moving with him. The protocol enables to distinguish ego-centered and hetero-centered perspectives.Results: We show that (1 OBT was possible but difficult for children with neurodevelopmental disorders, as well as for TD children, when the task required the participant to perform a mental rotation in order to adopt a hetero-centered perspective. (2 Using multivariate models, hetero-centered perspective score was significantly associated with age, TW orientation, latency, and diagnosis. ASD and TD groups' performances were close and significantly correlated with age. However, it was not the case for DCD, since this group was specifically handicapped by visual-spatial impairments. (3 ASD and DCD did not perform similarly: motor performance as shown by movement amplitude was better in DCD than ASD. ASD motor response was more ambiguous and hardly readable.Conclusion: Changing perspective in a spatial environment is possible for patients with ASD although delayed compared with TD children. In patients with DCD, their visual-spatial impairments negatively

  2. Behavior of ionic species in biomolecular reactions

    International Nuclear Information System (INIS)

    Seki, Hiroyuki

    1974-01-01

    Studies were made on short-lived intermediates such as neutral radicals, activated molecules, and radical ions, which appear and disappear accompanying various reactions in living organisms, especially on the behavior of the ionic species of chlorophyl a (Chl. a) and on the reductive cutting of the cobalt-carbon linkage in Vitamin B 12 and coenzyme-type B 12 . A rigid body of MTHF at 77 0 K, containing 3 mM Chl. a, was irradiated with γ ray, and captured electrons which did not react were bleached with near-infrared light. Thus a spectrum of Chl. a - was obtained. The ESR spectrum of Chl. a - was also obtained. Examination of these spectra indicated that not only Chl. a + but also Chl. a - were formed in the course of photochemical synthesis. A methanol rigid body at 77 0 K containing 10 mM VB 12 was irradiated with γ ray, then captured electrons which did not react were bleached. Thus an electron spectrum and an ESR spectrum were obtained. Examination of these spectra indicated that the Co-C linkage was cut off even in a rigid body at 77 0 K when B 12 coenzyme was reduced by electron capture and Bsub(12s) and 5'-deoxyadenosyl radical were formed. (Fukutomi, T.)

  3. CT-3DRA registration for radiosurgery treatments: a comparison among rigid, affine and non rigid approaches

    International Nuclear Information System (INIS)

    Stancanello, J.; Loeckx, D.; Francescon, P.; Calvedon, C.; Avanzo, M.; Cora, S.; Scalchi, P.; Cerveri, P.; Ferrigno, G.

    2004-01-01

    This work aims at comparing rigid, affine and Local Non Rigid (LNR) CT-3D Rotational Angiography (CT-3DRA) registrations based on mutual information. 10 cranial and 1 spinal cases have been registered by rigid and affine transformations; while LNR has been applied to the cases where residual deformation must be corrected. An example of CT-3DRA registration without regularization term and an example of LNR using the similarity criterion and the regularization term as well as 3D superposition of the 3DRA before and after the registration without the regularization term are presented. All the registrations performed by rigid transformation converged to an acceptable solution. The results about the robustness test in axial direction are reported. Conclusions: For cranial cases, affine transformation endowed with threshold-segmentation pre-processing can be considered the most favourable solution for almost all registrations; for some cases, LNR provides more accurate results. For the spinal case rigid transformation is the most suitable when immobilizing patient during examinations; in this case the increase of accuracy by using LNR registrations seems to be not significant

  4. Mealtime behavior among siblings and body mass index of 4-8 year olds: a videotaped observational study.

    Science.gov (United States)

    Mosli, Rana H; Miller, Alison L; Kaciroti, Niko; Peterson, Karen E; Rosenblum, Katherine; Baylin, Ana; Lumeng, Julie C

    2015-07-15

    Being a last-born child and having a sister have been associated with higher body mass index (BMI). Encouragement to eat that overrides children's self-regulation has been reported to increase the risk of obesogenic eating behaviors. This study sought to test the hypothesis that encouragement to eat during mealtime from older siblings and sisters mediates associations of being last-born or having a sister with higher BMI. Children aged 4-8 years (n = 75) were videotaped while eating a routine evening meal at home with one sibling present. Encouragement to eat (defined as direct prompts to eat or general positive statements about food) delivered to the index child (IC) from the sibling was coded from the videotape. Path analysis was used to examine associations between IC's birth order, sibling's sex, encouragement counts, and IC's measured BMI z-score (BMIz). Being the younger sibling in the sibling dyad was associated with the IC receiving more encouragements to eat from the sibling (β: 0.93, 95 % confidence interval (CI): 0.59, 1.26, p eat from the sibling (β: 0.18, 95 % CI: -0.09, 0.47, p = 0.20). The IC receiving more encouragements to eat from the sibling was associated with lower IC BMIz (β: -0.06, 95 % CI: -0.12, 0.00, p = 0.05). Children were more likely to receive encouragements to eat from older siblings than younger siblings. Being the recipient of encouragements to eat from a sibling was associated with lower, not higher, child BMIz, which may reflect sibling modeling of maternal behavior. Future longitudinal studies are needed to examine whether encouragements to eat from siblings lead to increase in BMI over time. Encouragements from siblings may be a novel intervention target for obesity prevention.

  5. Slip Morphology of Elastic Strips on Frictional Rigid Substrates.

    Science.gov (United States)

    Sano, Tomohiko G; Yamaguchi, Tetsuo; Wada, Hirofumi

    2017-04-28

    The morphology of an elastic strip subject to vertical compressive stress on a frictional rigid substrate is investigated by a combination of theory and experiment. We find a rich variety of morphologies, which-when the bending elasticity dominates over the effect of gravity-are classified into three distinct types of states: pinned, partially slipped, and completely slipped, depending on the magnitude of the vertical strain and the coefficient of static friction. We develop a theory of elastica under mixed clamped-hinged boundary conditions combined with the Coulomb-Amontons friction law and find excellent quantitative agreement with simulations and controlled physical experiments. We also discuss the effect of gravity in order to bridge the difference in the qualitative behaviors of stiff strips and flexible strings or ropes. Our study thus complements recent work on elastic rope coiling and takes a significant step towards establishing a unified understanding of how a thin elastic object interacts vertically with a solid surface.

  6. JOINT RIGIDITY ASSESSMENT WITH PIEZOELECTRIC WAFERS AND ACOUSTIC WAVES

    International Nuclear Information System (INIS)

    Montoya, Angela C.; Maji, Arup K.

    2010-01-01

    There has been an interest in the development of rapid deployment satellites. In a modular satellite design, different panels of specific functions can be pre-manufactured. The satellite can then be assembled and tested just prior to deployment. Traditional vibration testing is time-consuming and expensive. An alternative test method to evaluate the connection between two plates will be proposed. The method investigated and described employs piezoelectric wafers to induce and sense lamb waves in two aluminum plates, which were joined by steel brackets to form an 'L-Style' joint. Lamb wave behavior and piezoelectric material properties will be discussed; the experimental setup and results will be presented. A set of 4 piezoelectric ceramic wafers were used alternately as source and sensor. The energy transmitted was shown to correlate with a mechanical assessment of the joint, demonstrating that this method of testing is a feasible and reliable way to inspect the rigidity of joints.

  7. Capital-Skill Complementarity and Rigid Relative Wages

    DEFF Research Database (Denmark)

    Rose Skaksen, Jan; Sørensen, Anders

    2004-01-01

    be countercyclical. The labor market is competitivein the United States and therefore relative wages of skilled labor are expected to becountercyclical. We find that the business cycle development of the two economiesis consistent with capital-skill complementarity.Keywords: capital-skill complementarity, relative......The relative demand for skills has increased considerably in many OECD countriesduring recent decades. This development is potentially explained by capital-skillcomplementarity and high growth rates of capital equipment. When productionfunctions are characterized by capital-skill complementarity......, relative wages and employmentof skilled labor are countercyclical because capital equipment is a quasi-fixed factor in the short run. The exact behavior of the two variables depends onrelative wage flexibility. Relative wages are rigid in Denmark, implying that the employmentshare of skills should...

  8. Effect of body mass distribution on the ontogeny of positional behaviors in non-human primates: Longitudinal follow-up of infant captive olive baboons (Papio anubis).

    Science.gov (United States)

    Druelle, François; Aerts, Peter; Berillon, Gilles

    2016-11-01

    The diversity of primates' positional capabilities is unique among mammals. Indeed, they exhibit a daily repertoire composed of various locomotor and postural modes that may be linked to their particular morphological pattern. Because ontogeny undergoes parallel behavioral and morphological modifications, it may be useful to investigate the biomechanical consequences of the changing body shape. We, therefore, collected accurate quantitative and longitudinal data on positional behaviors, body mass distribution patterns, activities, and environment on a sample of six infant olive baboons, Papio anubis. These baboons are kept at the Primatology Station of the CNRS, France, where they live within the same social group. Individual behaviors were quantified using the focal sampling method. The body mass distribution was estimated according to a geometric model based on direct external measurements. Multivariate analysis enabled us to analyze the interactions between the data. Our results show that body mass distribution changes together with the ontogenetic changes in positional behaviors. At an early age, individuals have distally heavy segment masses in the limbs and an important fraction of the behavioral repertoire involves efficient grasping abilities. At the end of infancy, the same individuals have relatively more mass in proximal segments of the limbs and the proportion of quadrupedal walking is significantly higher while other climbing and suspensory behaviors decreased substantially. The present study experimentally confirms the association between body mass distribution and the positional repertoire of primates. These relationships, when interpreted in the context of basic biomechanical concepts, may improve our understanding of primate locomotion. We discuss further the implications of these functional relationships when modeling the evolutionary pathway of primates. Am. J. Primatol. 78:1201-1221, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley

  9. A geometrically controlled rigidity transition in a model for confluent 3D tissues

    Science.gov (United States)

    Merkel, Matthias; Manning, M. Lisa

    2018-02-01

    The origin of rigidity in disordered materials is an outstanding open problem in statistical physics. Previously, a class of 2D cellular models has been shown to undergo a rigidity transition controlled by a mechanical parameter that specifies cell shapes. Here, we generalize this model to 3D and find a rigidity transition that is similarly controlled by the preferred surface area S 0: the model is solid-like below a dimensionless surface area of {s}0\\equiv {S}0/{\\bar{V}}2/3≈ 5.413 with \\bar{V} being the average cell volume, and fluid-like above this value. We demonstrate that, unlike jamming in soft spheres, residual stresses are necessary to create rigidity. These stresses occur precisely when cells are unable to obtain their desired geometry, and we conjecture that there is a well-defined minimal surface area possible for disordered cellular structures. We show that the behavior of this minimal surface induces a linear scaling of the shear modulus with the control parameter at the transition point, which is different from the scaling observed in particulate matter. The existence of such a minimal surface may be relevant for biological tissues and foams, and helps explain why cell shapes are a good structural order parameter for rigidity transitions in biological tissues.

  10. Uncommon, undeclared oesophageal foreign bodies

    African Journals Online (AJOL)

    2011-05-11

    May 11, 2011 ... presented with a sudden onset of total dysphagia and history of ingestion of foreign bodies was not volunteered by any despite direct questioning. Plain radiograph of the neck and chest in either case did not reveal presence of foreign body. Both were successfully removed through rigid oesophagoscopy.

  11. Influence of flock coating on bending rigidity of woven fabrics

    Science.gov (United States)

    Ozdemir, O.; Kesimci, M. O.

    2017-10-01

    This work presents the preliminary results of our efforts that focused on the effect of the flock coating on the bending rigidity of woven fabrics. For this objective, a laboratory scale flocking unit is designed and flocked samples of controlled flock density are produced. Bending rigidity of the samples with different flock densities are measured on both flocked and unflocked sides. It is shown that the bending rigidity depends on both flock density and whether the side to be measured is flocked or not. Adhesive layer thickness on the bending rigidity is shown to be dramatic. And at higher basis weights, flock density gets less effective on bending rigidity.

  12. Understanding geological processes: Visualization of rigid and non-rigid transformations

    Science.gov (United States)

    Shipley, T. F.; Atit, K.; Manduca, C. A.; Ormand, C. J.; Resnick, I.; Tikoff, B.

    2012-12-01

    Visualizations are used in the geological sciences to support reasoning about structures and events. Research in cognitive sciences offers insights into the range of skills of different users, and ultimately how visualizations might support different users. To understand the range of skills needed to reason about earth processes we have developed a program of research that is grounded in the geosciences' careful description of the spatial and spatiotemporal patterns associated with earth processes. In particular, we are pursuing a research program that identifies specific spatial skills and investigates whether and how they are related to each other. For this study, we focus on a specific question: Is there an important distinction in the geosciences between rigid and non-rigid deformation? To study a general spatial thinking skill we employed displays with non-geological objects that had been altered by rigid change (rotation), and two types of non-rigid change ("brittle" (or discontinuous) and "ductile" (or continuous) deformation). Disciplinary scientists (geosciences and chemistry faculty), and novices (non-science faculty and undergraduate psychology students) answered questions that required them to visualize the appearance of the object before the change. In one study, geologists and chemists were found to be superior to non-science faculty in reasoning about rigid rotations (e.g., what an object would look like from a different perspective). Geologists were superior to chemists in reasoning about brittle deformations (e.g., what an object looked like before it was broken - here the object was a word cut into many fragments displaced in different directions). This finding is consistent with two hypotheses: 1) Experts are good at visualizing the types of changes required for their domain; and 2) Visualization of rigid and non-rigid changes are not the same skill. An additional important finding is that there was a broad range of skill in both rigid and non-rigid

  13. Passive immunization reduces behavioral and neuropathological deficits in an alpha-synuclein transgenic model of Lewy body disease.

    Science.gov (United States)

    Masliah, Eliezer; Rockenstein, Edward; Mante, Michael; Crews, Leslie; Spencer, Brian; Adame, Anthony; Patrick, Christina; Trejo, Margarita; Ubhi, Kiren; Rohn, Troy T; Mueller-Steiner, Sarah; Seubert, Peter; Barbour, Robin; McConlogue, Lisa; Buttini, Manuel; Games, Dora; Schenk, Dale

    2011-04-29

    Dementia with Lewy bodies (DLB) and Parkinson's Disease (PD) are common causes of motor and cognitive deficits and are associated with the abnormal accumulation of alpha-synuclein (α-syn). This study investigated whether passive immunization with a novel monoclonal α-syn antibody (9E4) against the C-terminus (CT) of α-syn was able to cross into the CNS and ameliorate the deficits associated with α-syn accumulation. In this study we demonstrate that 9E4 was effective at reducing behavioral deficits in the water maze, moreover, immunization with 9E4 reduced the accumulation of calpain-cleaved α-syn in axons and synapses and the associated neurodegenerative deficits. In vivo studies demonstrated that 9E4 traffics into the CNS, binds to cells that display α-syn accumulation and promotes α-syn clearance via the lysosomal pathway. These results suggest that passive immunization with monoclonal antibodies against the CT of α-syn may be of therapeutic relevance in patients with PD and DLB.

  14. Effect of Ultrasonic Surface Impact on the Fatigue Behavior of Ti-6Al-4V Subject to Simulated Body Fluid

    Directory of Open Access Journals (Sweden)

    Xiaojian Cao

    2017-10-01

    Full Text Available The effect of ultrasonic nanocrystal surface modification (UNSM on the fatigue behavior of Ti6Al4V (TC4 in simulated body fluid (SBF was investigated. UNSM with the condition of a static load of 25 N, vibration amplitude of 30 μm and 36,000 strikes per unit produced about 35 μm surface severe plastic deformation (SPD layers on the TC4 specimens. One group was treated with a hybrid surface treatment (UNSM + TiN film. UNSM technique improves the micro hardness and the compressive residual stress. The surface roughness is increased slightly, but it can be remarkably improved by the TiN film. The fatigue strength of TC4 is improved by about 7.9% after UNSM. Though the current density of corrosion is increased and the pitting corrosion is accelerated, UNSM still improved the fatigue strength of TC4 after pre-soaking in SBF by 10.8%. Interior cracks initiate at the deformed carbide and oxide inclusions due to the ultrasonic impacts of UNSM. Corrosion products are always observed at the edge of fracture surface to both interior cracks and surface cracks. Coating a TiN film on the UNSMed surface helps to improve the whole properties of TC4 further.

  15. Corrosion fatigue behaviors of two biomedical Mg alloys - AZ91D and WE43 - In simulated body fluid.

    Science.gov (United States)

    Gu, X N; Zhou, W R; Zheng, Y F; Cheng, Y; Wei, S C; Zhong, S P; Xi, T F; Chen, L J

    2010-12-01

    Magnesium alloys have been recently developed as biodegradable implant materials, yet there has been no study concerning their corrosion fatigue properties under cyclic loading. In this study the die-cast AZ91D (A for aluminum 9%, Z for zinc 1% and D for a fourth phase) and extruded WE43 (W for yttrium 4%, E for rare earth mischmetal 3%) alloys were chosen to evaluate their fatigue and corrosion fatigue behaviors in simulated body fluid (SBF). The die-cast AZ91D alloy indicated a fatigue limit of 50MPa at 10⁷ cycles in air compared to 20MPa at 10⁶ cycles tested in SBF at 37°C. A fatigue limit of 110MPa at 10⁷ cycles in air was observed for extruded WE43 alloy compared to 40MPa at 10⁷ cycles tested in SBF at 37°C. The fatigue cracks initiated from the micropores when tested in air and from corrosion pits when tested in SBF, respectively. The overload zone of the extruded WE43 alloy exhibited a ductile fracture mode with deep dimples, in comparison to a brittle fracture mode for the die-cast AZ91D. The corrosion rate of the two experimental alloys increased under cyclic loading compared to that in the static immersion test. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  16. Diet- and Body Size-related Attitudes and Behaviors Associated with Vitamin Supplement Use in a Representative Sample of Fourth-grade Students in Texas

    Science.gov (United States)

    The objective of this research was to examine diet- and body size-related attitudes and behaviors associated with supplement use in a representative sample of fourth-grade students in Texas. The research design consisted of cross-sectional data from the School Physical Activity and Nutrition study, ...

  17. Healthy Life Style Behaviors of University Students of School of Physical Education and Sports in Terms of Body Mass Index and Other Variables

    Science.gov (United States)

    Bozlar, Volkan; Arslanoglu, Cansel

    2016-01-01

    The aim of this study is to determine Healthy Lifestyle Behaviors of students in the Schools of Physical Education and Sport (SPES) utilizing Body Mass Index (BMI) and other various variables. The study is composed of 1,695 students studying in SPES, in 14 different universities across Turkey. It is made up of 1,067 male and 624 female students.…

  18. Identifying developmental trajectories of body mass index in childhood using latent class growth (mixture) modelling : associations with dietary, sedentary and physical activity behaviors: a longitudinal study

    NARCIS (Netherlands)

    Koning, Maaike; Hoekstra, Trynke; de Jong, Elske; Visscher, Tommy L.S.; Seidell, Jacob C.; Renders, Carry M.

    2016-01-01

    BACKGROUND: To date, many epidemiologic studies examining associations between obesity and dietary and sedentary/physical activity behaviors have focused on assessing Body Mass Index (BMI) at one point in time. Recent developments in statistical techniques make it possible to study the potential

  19. Can Ethnic Background Differences in Children's Body Composition Be Explained by Differences in Energy Balance-Related Behaviors? A Mediation Analysis within the Energy-Project

    NARCIS (Netherlands)

    Fernandez Alvira, J.M.; te Velde, S.J.; Jimenez-Pavon, D.; Manios, Y.; Singh, A.S.; Moreno, L.A.; Brug, J.

    2013-01-01

    Background:In affluent countries, children from non-native ethnicity have in general less favourable body composition indicators and energy balance-related behaviors (EBRBs) than children from native ethnicity. However, differences between countries have been reported.Methodology/Principal

  20. The Social Environment of Schools and Adolescent Nutrition: Associations between the School Nutrition Climate and Adolescents' Eating Behaviors and Body Mass Index

    Science.gov (United States)

    Cvjetan, Branko; Utter, Jennifer; Robinson, Elizabeth; Denny, Simon

    2014-01-01

    Background: The aim of this study was to determine the association between the school nutrition climate and students' eating behaviors and body mass index (BMI). Methods: Data were collected as part of Youth'07, a nationally representative health survey of high school students in New Zealand. Overall, 9107 randomly selected students from 96…